28 * Packet type contexts, so that ssh2_pkt_type can correctly decode
29 * the ambiguous type numbers back into the correct type strings.
40 SSH2_PKTCTX_PUBLICKEY,
46 static const char *const ssh2_disconnect_reasons[] = {
48 "host not allowed to connect",
50 "key exchange failed",
51 "host authentication failed",
54 "service not available",
55 "protocol version not supported",
56 "host key not verifiable",
59 "too many connections",
60 "auth cancelled by user",
61 "no more auth methods available",
66 * Various remote-bug flags.
68 #define BUG_CHOKES_ON_SSH1_IGNORE 1
69 #define BUG_SSH2_HMAC 2
70 #define BUG_NEEDS_SSH1_PLAIN_PASSWORD 4
71 #define BUG_CHOKES_ON_RSA 8
72 #define BUG_SSH2_RSA_PADDING 16
73 #define BUG_SSH2_DERIVEKEY 32
74 #define BUG_SSH2_REKEY 64
75 #define BUG_SSH2_PK_SESSIONID 128
76 #define BUG_SSH2_MAXPKT 256
77 #define BUG_CHOKES_ON_SSH2_IGNORE 512
78 #define BUG_CHOKES_ON_WINADJ 1024
79 #define BUG_SENDS_LATE_REQUEST_REPLY 2048
80 #define BUG_SSH2_OLDGEX 4096
82 #define DH_MIN_SIZE 1024
83 #define DH_MAX_SIZE 8192
86 * Codes for terminal modes.
87 * Most of these are the same in SSH-1 and SSH-2.
88 * This list is derived from RFC 4254 and
92 const char* const mode;
94 enum { TTY_OP_CHAR, TTY_OP_BOOL } type;
96 /* "V" prefix discarded for special characters relative to SSH specs */
97 { "INTR", 1, TTY_OP_CHAR },
98 { "QUIT", 2, TTY_OP_CHAR },
99 { "ERASE", 3, TTY_OP_CHAR },
100 { "KILL", 4, TTY_OP_CHAR },
101 { "EOF", 5, TTY_OP_CHAR },
102 { "EOL", 6, TTY_OP_CHAR },
103 { "EOL2", 7, TTY_OP_CHAR },
104 { "START", 8, TTY_OP_CHAR },
105 { "STOP", 9, TTY_OP_CHAR },
106 { "SUSP", 10, TTY_OP_CHAR },
107 { "DSUSP", 11, TTY_OP_CHAR },
108 { "REPRINT", 12, TTY_OP_CHAR },
109 { "WERASE", 13, TTY_OP_CHAR },
110 { "LNEXT", 14, TTY_OP_CHAR },
111 { "FLUSH", 15, TTY_OP_CHAR },
112 { "SWTCH", 16, TTY_OP_CHAR },
113 { "STATUS", 17, TTY_OP_CHAR },
114 { "DISCARD", 18, TTY_OP_CHAR },
115 { "IGNPAR", 30, TTY_OP_BOOL },
116 { "PARMRK", 31, TTY_OP_BOOL },
117 { "INPCK", 32, TTY_OP_BOOL },
118 { "ISTRIP", 33, TTY_OP_BOOL },
119 { "INLCR", 34, TTY_OP_BOOL },
120 { "IGNCR", 35, TTY_OP_BOOL },
121 { "ICRNL", 36, TTY_OP_BOOL },
122 { "IUCLC", 37, TTY_OP_BOOL },
123 { "IXON", 38, TTY_OP_BOOL },
124 { "IXANY", 39, TTY_OP_BOOL },
125 { "IXOFF", 40, TTY_OP_BOOL },
126 { "IMAXBEL", 41, TTY_OP_BOOL },
127 { "ISIG", 50, TTY_OP_BOOL },
128 { "ICANON", 51, TTY_OP_BOOL },
129 { "XCASE", 52, TTY_OP_BOOL },
130 { "ECHO", 53, TTY_OP_BOOL },
131 { "ECHOE", 54, TTY_OP_BOOL },
132 { "ECHOK", 55, TTY_OP_BOOL },
133 { "ECHONL", 56, TTY_OP_BOOL },
134 { "NOFLSH", 57, TTY_OP_BOOL },
135 { "TOSTOP", 58, TTY_OP_BOOL },
136 { "IEXTEN", 59, TTY_OP_BOOL },
137 { "ECHOCTL", 60, TTY_OP_BOOL },
138 { "ECHOKE", 61, TTY_OP_BOOL },
139 { "PENDIN", 62, TTY_OP_BOOL }, /* XXX is this a real mode? */
140 { "OPOST", 70, TTY_OP_BOOL },
141 { "OLCUC", 71, TTY_OP_BOOL },
142 { "ONLCR", 72, TTY_OP_BOOL },
143 { "OCRNL", 73, TTY_OP_BOOL },
144 { "ONOCR", 74, TTY_OP_BOOL },
145 { "ONLRET", 75, TTY_OP_BOOL },
146 { "CS7", 90, TTY_OP_BOOL },
147 { "CS8", 91, TTY_OP_BOOL },
148 { "PARENB", 92, TTY_OP_BOOL },
149 { "PARODD", 93, TTY_OP_BOOL }
152 /* Miscellaneous other tty-related constants. */
153 #define SSH_TTY_OP_END 0
154 /* The opcodes for ISPEED/OSPEED differ between SSH-1 and SSH-2. */
155 #define SSH1_TTY_OP_ISPEED 192
156 #define SSH1_TTY_OP_OSPEED 193
157 #define SSH2_TTY_OP_ISPEED 128
158 #define SSH2_TTY_OP_OSPEED 129
160 /* Helper functions for parsing tty-related config. */
161 static unsigned int ssh_tty_parse_specchar(char *s)
166 ret = ctrlparse(s, &next);
167 if (!next) ret = s[0];
169 ret = 255; /* special value meaning "don't set" */
173 static unsigned int ssh_tty_parse_boolean(char *s)
175 if (stricmp(s, "yes") == 0 ||
176 stricmp(s, "on") == 0 ||
177 stricmp(s, "true") == 0 ||
178 stricmp(s, "+") == 0)
180 else if (stricmp(s, "no") == 0 ||
181 stricmp(s, "off") == 0 ||
182 stricmp(s, "false") == 0 ||
183 stricmp(s, "-") == 0)
184 return 0; /* false */
186 return (atoi(s) != 0);
189 #define translate(x) if (type == x) return #x
190 #define translatek(x,ctx) if (type == x && (pkt_kctx == ctx)) return #x
191 #define translatea(x,ctx) if (type == x && (pkt_actx == ctx)) return #x
192 static const char *ssh1_pkt_type(int type)
194 translate(SSH1_MSG_DISCONNECT);
195 translate(SSH1_SMSG_PUBLIC_KEY);
196 translate(SSH1_CMSG_SESSION_KEY);
197 translate(SSH1_CMSG_USER);
198 translate(SSH1_CMSG_AUTH_RSA);
199 translate(SSH1_SMSG_AUTH_RSA_CHALLENGE);
200 translate(SSH1_CMSG_AUTH_RSA_RESPONSE);
201 translate(SSH1_CMSG_AUTH_PASSWORD);
202 translate(SSH1_CMSG_REQUEST_PTY);
203 translate(SSH1_CMSG_WINDOW_SIZE);
204 translate(SSH1_CMSG_EXEC_SHELL);
205 translate(SSH1_CMSG_EXEC_CMD);
206 translate(SSH1_SMSG_SUCCESS);
207 translate(SSH1_SMSG_FAILURE);
208 translate(SSH1_CMSG_STDIN_DATA);
209 translate(SSH1_SMSG_STDOUT_DATA);
210 translate(SSH1_SMSG_STDERR_DATA);
211 translate(SSH1_CMSG_EOF);
212 translate(SSH1_SMSG_EXIT_STATUS);
213 translate(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION);
214 translate(SSH1_MSG_CHANNEL_OPEN_FAILURE);
215 translate(SSH1_MSG_CHANNEL_DATA);
216 translate(SSH1_MSG_CHANNEL_CLOSE);
217 translate(SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION);
218 translate(SSH1_SMSG_X11_OPEN);
219 translate(SSH1_CMSG_PORT_FORWARD_REQUEST);
220 translate(SSH1_MSG_PORT_OPEN);
221 translate(SSH1_CMSG_AGENT_REQUEST_FORWARDING);
222 translate(SSH1_SMSG_AGENT_OPEN);
223 translate(SSH1_MSG_IGNORE);
224 translate(SSH1_CMSG_EXIT_CONFIRMATION);
225 translate(SSH1_CMSG_X11_REQUEST_FORWARDING);
226 translate(SSH1_CMSG_AUTH_RHOSTS_RSA);
227 translate(SSH1_MSG_DEBUG);
228 translate(SSH1_CMSG_REQUEST_COMPRESSION);
229 translate(SSH1_CMSG_AUTH_TIS);
230 translate(SSH1_SMSG_AUTH_TIS_CHALLENGE);
231 translate(SSH1_CMSG_AUTH_TIS_RESPONSE);
232 translate(SSH1_CMSG_AUTH_CCARD);
233 translate(SSH1_SMSG_AUTH_CCARD_CHALLENGE);
234 translate(SSH1_CMSG_AUTH_CCARD_RESPONSE);
237 static const char *ssh2_pkt_type(Pkt_KCtx pkt_kctx, Pkt_ACtx pkt_actx,
240 translatea(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE,SSH2_PKTCTX_GSSAPI);
241 translatea(SSH2_MSG_USERAUTH_GSSAPI_TOKEN,SSH2_PKTCTX_GSSAPI);
242 translatea(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE,SSH2_PKTCTX_GSSAPI);
243 translatea(SSH2_MSG_USERAUTH_GSSAPI_ERROR,SSH2_PKTCTX_GSSAPI);
244 translatea(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK,SSH2_PKTCTX_GSSAPI);
245 translatea(SSH2_MSG_USERAUTH_GSSAPI_MIC, SSH2_PKTCTX_GSSAPI);
246 translate(SSH2_MSG_DISCONNECT);
247 translate(SSH2_MSG_IGNORE);
248 translate(SSH2_MSG_UNIMPLEMENTED);
249 translate(SSH2_MSG_DEBUG);
250 translate(SSH2_MSG_SERVICE_REQUEST);
251 translate(SSH2_MSG_SERVICE_ACCEPT);
252 translate(SSH2_MSG_KEXINIT);
253 translate(SSH2_MSG_NEWKEYS);
254 translatek(SSH2_MSG_KEXDH_INIT, SSH2_PKTCTX_DHGROUP);
255 translatek(SSH2_MSG_KEXDH_REPLY, SSH2_PKTCTX_DHGROUP);
256 translatek(SSH2_MSG_KEX_DH_GEX_REQUEST_OLD, SSH2_PKTCTX_DHGEX);
257 translatek(SSH2_MSG_KEX_DH_GEX_REQUEST, SSH2_PKTCTX_DHGEX);
258 translatek(SSH2_MSG_KEX_DH_GEX_GROUP, SSH2_PKTCTX_DHGEX);
259 translatek(SSH2_MSG_KEX_DH_GEX_INIT, SSH2_PKTCTX_DHGEX);
260 translatek(SSH2_MSG_KEX_DH_GEX_REPLY, SSH2_PKTCTX_DHGEX);
261 translatek(SSH2_MSG_KEXRSA_PUBKEY, SSH2_PKTCTX_RSAKEX);
262 translatek(SSH2_MSG_KEXRSA_SECRET, SSH2_PKTCTX_RSAKEX);
263 translatek(SSH2_MSG_KEXRSA_DONE, SSH2_PKTCTX_RSAKEX);
264 translatek(SSH2_MSG_KEX_ECDH_INIT, SSH2_PKTCTX_ECDHKEX);
265 translatek(SSH2_MSG_KEX_ECDH_REPLY, SSH2_PKTCTX_ECDHKEX);
266 translate(SSH2_MSG_USERAUTH_REQUEST);
267 translate(SSH2_MSG_USERAUTH_FAILURE);
268 translate(SSH2_MSG_USERAUTH_SUCCESS);
269 translate(SSH2_MSG_USERAUTH_BANNER);
270 translatea(SSH2_MSG_USERAUTH_PK_OK, SSH2_PKTCTX_PUBLICKEY);
271 translatea(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, SSH2_PKTCTX_PASSWORD);
272 translatea(SSH2_MSG_USERAUTH_INFO_REQUEST, SSH2_PKTCTX_KBDINTER);
273 translatea(SSH2_MSG_USERAUTH_INFO_RESPONSE, SSH2_PKTCTX_KBDINTER);
274 translate(SSH2_MSG_GLOBAL_REQUEST);
275 translate(SSH2_MSG_REQUEST_SUCCESS);
276 translate(SSH2_MSG_REQUEST_FAILURE);
277 translate(SSH2_MSG_CHANNEL_OPEN);
278 translate(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
279 translate(SSH2_MSG_CHANNEL_OPEN_FAILURE);
280 translate(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
281 translate(SSH2_MSG_CHANNEL_DATA);
282 translate(SSH2_MSG_CHANNEL_EXTENDED_DATA);
283 translate(SSH2_MSG_CHANNEL_EOF);
284 translate(SSH2_MSG_CHANNEL_CLOSE);
285 translate(SSH2_MSG_CHANNEL_REQUEST);
286 translate(SSH2_MSG_CHANNEL_SUCCESS);
287 translate(SSH2_MSG_CHANNEL_FAILURE);
293 /* Enumeration values for fields in SSH-1 packets */
295 PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR, PKT_BIGNUM,
299 * Coroutine mechanics for the sillier bits of the code. If these
300 * macros look impenetrable to you, you might find it helpful to
303 * http://www.chiark.greenend.org.uk/~sgtatham/coroutines.html
305 * which explains the theory behind these macros.
307 * In particular, if you are getting `case expression not constant'
308 * errors when building with MS Visual Studio, this is because MS's
309 * Edit and Continue debugging feature causes their compiler to
310 * violate ANSI C. To disable Edit and Continue debugging:
312 * - right-click ssh.c in the FileView
314 * - select the C/C++ tab and the General category
315 * - under `Debug info:', select anything _other_ than `Program
316 * Database for Edit and Continue'.
318 #define crBegin(v) { int *crLine = &v; switch(v) { case 0:;
319 #define crBeginState crBegin(s->crLine)
320 #define crStateP(t, v) \
322 if (!(v)) { s = (v) = snew(struct t); s->crLine = 0; } \
324 #define crState(t) crStateP(t, ssh->t)
325 #define crFinish(z) } *crLine = 0; return (z); }
326 #define crFinishV } *crLine = 0; return; }
327 #define crFinishFree(z) } sfree(s); return (z); }
328 #define crFinishFreeV } sfree(s); return; }
329 #define crReturn(z) \
331 *crLine =__LINE__; return (z); case __LINE__:;\
335 *crLine=__LINE__; return; case __LINE__:;\
337 #define crStop(z) do{ *crLine = 0; return (z); }while(0)
338 #define crStopV do{ *crLine = 0; return; }while(0)
339 #define crWaitUntil(c) do { crReturn(0); } while (!(c))
340 #define crWaitUntilV(c) do { crReturnV; } while (!(c))
344 static struct Packet *ssh1_pkt_init(int pkt_type);
345 static struct Packet *ssh2_pkt_init(int pkt_type);
346 static void ssh_pkt_ensure(struct Packet *, int length);
347 static void ssh_pkt_adddata(struct Packet *, const void *data, int len);
348 static void ssh_pkt_addbyte(struct Packet *, unsigned char value);
349 static void ssh2_pkt_addbool(struct Packet *, unsigned char value);
350 static void ssh_pkt_adduint32(struct Packet *, unsigned long value);
351 static void ssh_pkt_addstring_start(struct Packet *);
352 static void ssh_pkt_addstring_str(struct Packet *, const char *data);
353 static void ssh_pkt_addstring_data(struct Packet *, const char *data, int len);
354 static void ssh_pkt_addstring(struct Packet *, const char *data);
355 static unsigned char *ssh2_mpint_fmt(Bignum b, int *len);
356 static void ssh1_pkt_addmp(struct Packet *, Bignum b);
357 static void ssh2_pkt_addmp(struct Packet *, Bignum b);
358 static int ssh2_pkt_construct(Ssh, struct Packet *);
359 static void ssh2_pkt_send(Ssh, struct Packet *);
360 static void ssh2_pkt_send_noqueue(Ssh, struct Packet *);
361 static int do_ssh1_login(Ssh ssh, const unsigned char *in, int inlen,
362 struct Packet *pktin);
363 static void do_ssh2_authconn(Ssh ssh, const unsigned char *in, int inlen,
364 struct Packet *pktin);
365 static void ssh2_channel_check_close(struct ssh_channel *c);
366 static void ssh_channel_destroy(struct ssh_channel *c);
367 static void ssh2_msg_something_unimplemented(Ssh ssh, struct Packet *pktin);
370 * Buffer management constants. There are several of these for
371 * various different purposes:
373 * - SSH1_BUFFER_LIMIT is the amount of backlog that must build up
374 * on a local data stream before we throttle the whole SSH
375 * connection (in SSH-1 only). Throttling the whole connection is
376 * pretty drastic so we set this high in the hope it won't
379 * - SSH_MAX_BACKLOG is the amount of backlog that must build up
380 * on the SSH connection itself before we defensively throttle
381 * _all_ local data streams. This is pretty drastic too (though
382 * thankfully unlikely in SSH-2 since the window mechanism should
383 * ensure that the server never has any need to throttle its end
384 * of the connection), so we set this high as well.
386 * - OUR_V2_WINSIZE is the maximum window size we present on SSH-2
389 * - OUR_V2_BIGWIN is the window size we advertise for the only
390 * channel in a simple connection. It must be <= INT_MAX.
392 * - OUR_V2_MAXPKT is the official "maximum packet size" we send
393 * to the remote side. This actually has nothing to do with the
394 * size of the _packet_, but is instead a limit on the amount
395 * of data we're willing to receive in a single SSH2 channel
398 * - OUR_V2_PACKETLIMIT is actually the maximum size of SSH
399 * _packet_ we're prepared to cope with. It must be a multiple
400 * of the cipher block size, and must be at least 35000.
403 #define SSH1_BUFFER_LIMIT 32768
404 #define SSH_MAX_BACKLOG 32768
405 #define OUR_V2_WINSIZE 16384
406 #define OUR_V2_BIGWIN 0x7fffffff
407 #define OUR_V2_MAXPKT 0x4000UL
408 #define OUR_V2_PACKETLIMIT 0x9000UL
410 const static struct ssh_signkey *hostkey_algs[] = {
412 &ssh_ecdsa_nistp256, &ssh_ecdsa_nistp384, &ssh_ecdsa_nistp521,
416 const static struct ssh_mac *macs[] = {
417 &ssh_hmac_sha256, &ssh_hmac_sha1, &ssh_hmac_sha1_96, &ssh_hmac_md5
419 const static struct ssh_mac *buggymacs[] = {
420 &ssh_hmac_sha1_buggy, &ssh_hmac_sha1_96_buggy, &ssh_hmac_md5
423 static void *ssh_comp_none_init(void)
427 static void ssh_comp_none_cleanup(void *handle)
430 static int ssh_comp_none_block(void *handle, unsigned char *block, int len,
431 unsigned char **outblock, int *outlen)
435 static int ssh_comp_none_disable(void *handle)
439 const static struct ssh_compress ssh_comp_none = {
441 ssh_comp_none_init, ssh_comp_none_cleanup, ssh_comp_none_block,
442 ssh_comp_none_init, ssh_comp_none_cleanup, ssh_comp_none_block,
443 ssh_comp_none_disable, NULL
445 extern const struct ssh_compress ssh_zlib;
446 const static struct ssh_compress *compressions[] = {
447 &ssh_zlib, &ssh_comp_none
450 enum { /* channel types */
455 CHAN_SOCKDATA_DORMANT, /* one the remote hasn't confirmed */
457 * CHAN_SHARING indicates a channel which is tracked here on
458 * behalf of a connection-sharing downstream. We do almost nothing
459 * with these channels ourselves: all messages relating to them
460 * get thrown straight to sshshare.c and passed on almost
461 * unmodified to downstream.
465 * CHAN_ZOMBIE is used to indicate a channel for which we've
466 * already destroyed the local data source: for instance, if a
467 * forwarded port experiences a socket error on the local side, we
468 * immediately destroy its local socket and turn the SSH channel
474 typedef void (*handler_fn_t)(Ssh ssh, struct Packet *pktin);
475 typedef void (*chandler_fn_t)(Ssh ssh, struct Packet *pktin, void *ctx);
476 typedef void (*cchandler_fn_t)(struct ssh_channel *, struct Packet *, void *);
479 * Each channel has a queue of outstanding CHANNEL_REQUESTS and their
482 struct outstanding_channel_request {
483 cchandler_fn_t handler;
485 struct outstanding_channel_request *next;
489 * 2-3-4 tree storing channels.
492 Ssh ssh; /* pointer back to main context */
493 unsigned remoteid, localid;
495 /* True if we opened this channel but server hasn't confirmed. */
498 * In SSH-1, this value contains four bits:
500 * 1 We have sent SSH1_MSG_CHANNEL_CLOSE.
501 * 2 We have sent SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION.
502 * 4 We have received SSH1_MSG_CHANNEL_CLOSE.
503 * 8 We have received SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION.
505 * A channel is completely finished with when all four bits are set.
507 * In SSH-2, the four bits mean:
509 * 1 We have sent SSH2_MSG_CHANNEL_EOF.
510 * 2 We have sent SSH2_MSG_CHANNEL_CLOSE.
511 * 4 We have received SSH2_MSG_CHANNEL_EOF.
512 * 8 We have received SSH2_MSG_CHANNEL_CLOSE.
514 * A channel is completely finished with when we have both sent
515 * and received CLOSE.
517 * The symbolic constants below use the SSH-2 terminology, which
518 * is a bit confusing in SSH-1, but we have to use _something_.
520 #define CLOSES_SENT_EOF 1
521 #define CLOSES_SENT_CLOSE 2
522 #define CLOSES_RCVD_EOF 4
523 #define CLOSES_RCVD_CLOSE 8
527 * This flag indicates that an EOF is pending on the outgoing side
528 * of the channel: that is, wherever we're getting the data for
529 * this channel has sent us some data followed by EOF. We can't
530 * actually send the EOF until we've finished sending the data, so
531 * we set this flag instead to remind us to do so once our buffer
537 * True if this channel is causing the underlying connection to be
542 struct ssh2_data_channel {
544 unsigned remwindow, remmaxpkt;
545 /* locwindow is signed so we can cope with excess data. */
546 int locwindow, locmaxwin;
548 * remlocwin is the amount of local window that we think
549 * the remote end had available to it after it sent the
550 * last data packet or window adjust ack.
554 * These store the list of channel requests that haven't
557 struct outstanding_channel_request *chanreq_head, *chanreq_tail;
558 enum { THROTTLED, UNTHROTTLING, UNTHROTTLED } throttle_state;
562 struct ssh_agent_channel {
563 unsigned char *message;
564 unsigned char msglen[4];
565 unsigned lensofar, totallen;
566 int outstanding_requests;
568 struct ssh_x11_channel {
569 struct X11Connection *xconn;
572 struct ssh_pfd_channel {
573 struct PortForwarding *pf;
575 struct ssh_sharing_channel {
582 * 2-3-4 tree storing remote->local port forwardings. SSH-1 and SSH-2
583 * use this structure in different ways, reflecting SSH-2's
584 * altogether saner approach to port forwarding.
586 * In SSH-1, you arrange a remote forwarding by sending the server
587 * the remote port number, and the local destination host:port.
588 * When a connection comes in, the server sends you back that
589 * host:port pair, and you connect to it. This is a ready-made
590 * security hole if you're not on the ball: a malicious server
591 * could send you back _any_ host:port pair, so if you trustingly
592 * connect to the address it gives you then you've just opened the
593 * entire inside of your corporate network just by connecting
594 * through it to a dodgy SSH server. Hence, we must store a list of
595 * host:port pairs we _are_ trying to forward to, and reject a
596 * connection request from the server if it's not in the list.
598 * In SSH-2, each side of the connection minds its own business and
599 * doesn't send unnecessary information to the other. You arrange a
600 * remote forwarding by sending the server just the remote port
601 * number. When a connection comes in, the server tells you which
602 * of its ports was connected to; and _you_ have to remember what
603 * local host:port pair went with that port number.
605 * Hence, in SSH-1 this structure is indexed by destination
606 * host:port pair, whereas in SSH-2 it is indexed by source port.
608 struct ssh_portfwd; /* forward declaration */
610 struct ssh_rportfwd {
611 unsigned sport, dport;
615 struct ssh_portfwd *pfrec;
618 static void free_rportfwd(struct ssh_rportfwd *pf)
621 sfree(pf->sportdesc);
629 * Separately to the rportfwd tree (which is for looking up port
630 * open requests from the server), a tree of _these_ structures is
631 * used to keep track of all the currently open port forwardings,
632 * so that we can reconfigure in mid-session if the user requests
636 enum { DESTROY, KEEP, CREATE } status;
638 unsigned sport, dport;
641 struct ssh_rportfwd *remote;
643 struct PortListener *local;
645 #define free_portfwd(pf) ( \
646 ((pf) ? (sfree((pf)->saddr), sfree((pf)->daddr), \
647 sfree((pf)->sserv), sfree((pf)->dserv)) : (void)0 ), sfree(pf) )
650 long length; /* length of packet: see below */
651 long forcepad; /* SSH-2: force padding to at least this length */
652 int type; /* only used for incoming packets */
653 unsigned long sequence; /* SSH-2 incoming sequence number */
654 unsigned char *data; /* allocated storage */
655 unsigned char *body; /* offset of payload within `data' */
656 long savedpos; /* dual-purpose saved packet position: see below */
657 long maxlen; /* amount of storage allocated for `data' */
658 long encrypted_len; /* for SSH-2 total-size counting */
661 * A note on the 'length' and 'savedpos' fields above.
663 * Incoming packets are set up so that pkt->length is measured
664 * relative to pkt->body, which itself points to a few bytes after
665 * pkt->data (skipping some uninteresting header fields including
666 * the packet type code). The ssh_pkt_get* functions all expect
667 * this setup, and they also use pkt->savedpos to indicate how far
668 * through the packet being decoded they've got - and that, too,
669 * is an offset from pkt->body rather than pkt->data.
671 * During construction of an outgoing packet, however, pkt->length
672 * is measured relative to the base pointer pkt->data, and
673 * pkt->body is not really used for anything until the packet is
674 * ready for sending. In this mode, pkt->savedpos is reused as a
675 * temporary variable by the addstring functions, which write out
676 * a string length field and then keep going back and updating it
677 * as more data is appended to the subsequent string data field;
678 * pkt->savedpos stores the offset (again relative to pkt->data)
679 * of the start of the string data field.
682 /* Extra metadata used in SSH packet logging mode, allowing us to
683 * log in the packet header line that the packet came from a
684 * connection-sharing downstream and what if anything unusual was
685 * done to it. The additional_log_text field is expected to be a
686 * static string - it will not be freed. */
687 unsigned downstream_id;
688 const char *additional_log_text;
691 static void ssh1_protocol(Ssh ssh, const void *vin, int inlen,
692 struct Packet *pktin);
693 static void ssh2_protocol(Ssh ssh, const void *vin, int inlen,
694 struct Packet *pktin);
695 static void ssh2_bare_connection_protocol(Ssh ssh, const void *vin, int inlen,
696 struct Packet *pktin);
697 static void ssh1_protocol_setup(Ssh ssh);
698 static void ssh2_protocol_setup(Ssh ssh);
699 static void ssh2_bare_connection_protocol_setup(Ssh ssh);
700 static void ssh_size(void *handle, int width, int height);
701 static void ssh_special(void *handle, Telnet_Special);
702 static int ssh2_try_send(struct ssh_channel *c);
703 static void ssh2_add_channel_data(struct ssh_channel *c,
704 const char *buf, int len);
705 static void ssh_throttle_all(Ssh ssh, int enable, int bufsize);
706 static void ssh2_set_window(struct ssh_channel *c, int newwin);
707 static int ssh_sendbuffer(void *handle);
708 static int ssh_do_close(Ssh ssh, int notify_exit);
709 static unsigned long ssh_pkt_getuint32(struct Packet *pkt);
710 static int ssh2_pkt_getbool(struct Packet *pkt);
711 static void ssh_pkt_getstring(struct Packet *pkt, char **p, int *length);
712 static void ssh2_timer(void *ctx, unsigned long now);
713 static void do_ssh2_transport(Ssh ssh, const void *vin, int inlen,
714 struct Packet *pktin);
715 static void ssh2_msg_unexpected(Ssh ssh, struct Packet *pktin);
717 struct rdpkt1_state_tag {
718 long len, pad, biglen, to_read;
719 unsigned long realcrc, gotcrc;
723 struct Packet *pktin;
726 struct rdpkt2_state_tag {
727 long len, pad, payload, packetlen, maclen;
730 unsigned long incoming_sequence;
731 struct Packet *pktin;
734 struct rdpkt2_bare_state_tag {
738 unsigned long incoming_sequence;
739 struct Packet *pktin;
742 struct queued_handler;
743 struct queued_handler {
745 chandler_fn_t handler;
747 struct queued_handler *next;
751 const struct plug_function_table *fn;
752 /* the above field _must_ be first in the structure */
762 unsigned char session_key[32];
764 int v1_remote_protoflags;
765 int v1_local_protoflags;
766 int agentfwd_enabled;
769 const struct ssh_cipher *cipher;
772 const struct ssh2_cipher *cscipher, *sccipher;
773 void *cs_cipher_ctx, *sc_cipher_ctx;
774 const struct ssh_mac *csmac, *scmac;
775 int csmac_etm, scmac_etm;
776 void *cs_mac_ctx, *sc_mac_ctx;
777 const struct ssh_compress *cscomp, *sccomp;
778 void *cs_comp_ctx, *sc_comp_ctx;
779 const struct ssh_kex *kex;
780 const struct ssh_signkey *hostkey;
781 char *hostkey_str; /* string representation, for easy checking in rekeys */
782 unsigned char v2_session_id[SSH2_KEX_MAX_HASH_LEN];
783 int v2_session_id_len;
787 int attempting_connshare;
793 int echoing, editing;
798 int ospeed, ispeed; /* temporaries */
799 int term_width, term_height;
801 tree234 *channels; /* indexed by local id */
802 struct ssh_channel *mainchan; /* primary session channel */
803 int ncmode; /* is primary channel direct-tcpip? */
808 tree234 *rportfwds, *portfwds;
812 SSH_STATE_BEFORE_SIZE,
818 int size_needed, eof_needed;
819 int sent_console_eof;
820 int got_pty; /* affects EOF behaviour on main channel */
822 struct Packet **queue;
823 int queuelen, queuesize;
825 unsigned char *deferred_send_data;
826 int deferred_len, deferred_size;
829 * Gross hack: pscp will try to start SFTP but fall back to
830 * scp1 if that fails. This variable is the means by which
831 * scp.c can reach into the SSH code and find out which one it
836 bufchain banner; /* accumulates banners during do_ssh2_authconn */
841 struct X11Display *x11disp;
842 struct X11FakeAuth *x11auth;
843 tree234 *x11authtree;
846 int conn_throttle_count;
849 int v1_stdout_throttling;
850 unsigned long v2_outgoing_sequence;
852 int ssh1_rdpkt_crstate;
853 int ssh2_rdpkt_crstate;
854 int ssh2_bare_rdpkt_crstate;
855 int ssh_gotdata_crstate;
856 int do_ssh1_connection_crstate;
858 void *do_ssh_init_state;
859 void *do_ssh1_login_state;
860 void *do_ssh2_transport_state;
861 void *do_ssh2_authconn_state;
862 void *do_ssh_connection_init_state;
864 struct rdpkt1_state_tag rdpkt1_state;
865 struct rdpkt2_state_tag rdpkt2_state;
866 struct rdpkt2_bare_state_tag rdpkt2_bare_state;
868 /* SSH-1 and SSH-2 use this for different things, but both use it */
869 int protocol_initial_phase_done;
871 void (*protocol) (Ssh ssh, const void *vin, int inlen,
873 struct Packet *(*s_rdpkt) (Ssh ssh, const unsigned char **data,
875 int (*do_ssh_init)(Ssh ssh, unsigned char c);
878 * We maintain our own copy of a Conf structure here. That way,
879 * when we're passed a new one for reconfiguration, we can check
880 * the differences and potentially reconfigure port forwardings
881 * etc in mid-session.
886 * Values cached out of conf so as to avoid the tree234 lookup
887 * cost every time they're used.
892 * Dynamically allocated username string created during SSH
893 * login. Stored in here rather than in the coroutine state so
894 * that it'll be reliably freed if we shut down the SSH session
895 * at some unexpected moment.
900 * Used to transfer data back from async callbacks.
902 void *agent_response;
903 int agent_response_len;
907 * The SSH connection can be set as `frozen', meaning we are
908 * not currently accepting incoming data from the network. This
909 * is slightly more serious than setting the _socket_ as
910 * frozen, because we may already have had data passed to us
911 * from the network which we need to delay processing until
912 * after the freeze is lifted, so we also need a bufchain to
916 bufchain queued_incoming_data;
919 * Dispatch table for packet types that we may have to deal
922 handler_fn_t packet_dispatch[256];
925 * Queues of one-off handler functions for success/failure
926 * indications from a request.
928 struct queued_handler *qhead, *qtail;
929 handler_fn_t q_saved_handler1, q_saved_handler2;
932 * This module deals with sending keepalives.
937 * Track incoming and outgoing data sizes and time, for
940 unsigned long incoming_data_size, outgoing_data_size, deferred_data_size;
941 unsigned long max_data_size;
943 unsigned long next_rekey, last_rekey;
944 const char *deferred_rekey_reason;
947 * Fully qualified host name, which we need if doing GSSAPI.
953 * GSSAPI libraries for this session.
955 struct ssh_gss_liblist *gsslibs;
959 * The last list returned from get_specials.
961 struct telnet_special *specials;
964 #define logevent(s) logevent(ssh->frontend, s)
966 /* logevent, only printf-formatted. */
967 static void logeventf(Ssh ssh, const char *fmt, ...)
973 buf = dupvprintf(fmt, ap);
979 static void bomb_out(Ssh ssh, char *text)
981 ssh_do_close(ssh, FALSE);
983 connection_fatal(ssh->frontend, "%s", text);
987 #define bombout(msg) bomb_out(ssh, dupprintf msg)
989 /* Helper function for common bits of parsing ttymodes. */
990 static void parse_ttymodes(Ssh ssh,
991 void (*do_mode)(void *data, char *mode, char *val),
996 for (val = conf_get_str_strs(ssh->conf, CONF_ttymodes, NULL, &key);
998 val = conf_get_str_strs(ssh->conf, CONF_ttymodes, key, &key)) {
1000 * val[0] is either 'V', indicating that an explicit value
1001 * follows it, or 'A' indicating that we should pass the
1002 * value through from the local environment via get_ttymode.
1004 if (val[0] == 'A') {
1005 val = get_ttymode(ssh->frontend, key);
1007 do_mode(data, key, val);
1011 do_mode(data, key, val + 1); /* skip the 'V' */
1015 static int ssh_channelcmp(void *av, void *bv)
1017 struct ssh_channel *a = (struct ssh_channel *) av;
1018 struct ssh_channel *b = (struct ssh_channel *) bv;
1019 if (a->localid < b->localid)
1021 if (a->localid > b->localid)
1025 static int ssh_channelfind(void *av, void *bv)
1027 unsigned *a = (unsigned *) av;
1028 struct ssh_channel *b = (struct ssh_channel *) bv;
1029 if (*a < b->localid)
1031 if (*a > b->localid)
1036 static int ssh_rportcmp_ssh1(void *av, void *bv)
1038 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
1039 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
1041 if ( (i = strcmp(a->dhost, b->dhost)) != 0)
1042 return i < 0 ? -1 : +1;
1043 if (a->dport > b->dport)
1045 if (a->dport < b->dport)
1050 static int ssh_rportcmp_ssh2(void *av, void *bv)
1052 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
1053 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
1055 if ( (i = strcmp(a->shost, b->shost)) != 0)
1056 return i < 0 ? -1 : +1;
1057 if (a->sport > b->sport)
1059 if (a->sport < b->sport)
1065 * Special form of strcmp which can cope with NULL inputs. NULL is
1066 * defined to sort before even the empty string.
1068 static int nullstrcmp(const char *a, const char *b)
1070 if (a == NULL && b == NULL)
1076 return strcmp(a, b);
1079 static int ssh_portcmp(void *av, void *bv)
1081 struct ssh_portfwd *a = (struct ssh_portfwd *) av;
1082 struct ssh_portfwd *b = (struct ssh_portfwd *) bv;
1084 if (a->type > b->type)
1086 if (a->type < b->type)
1088 if (a->addressfamily > b->addressfamily)
1090 if (a->addressfamily < b->addressfamily)
1092 if ( (i = nullstrcmp(a->saddr, b->saddr)) != 0)
1093 return i < 0 ? -1 : +1;
1094 if (a->sport > b->sport)
1096 if (a->sport < b->sport)
1098 if (a->type != 'D') {
1099 if ( (i = nullstrcmp(a->daddr, b->daddr)) != 0)
1100 return i < 0 ? -1 : +1;
1101 if (a->dport > b->dport)
1103 if (a->dport < b->dport)
1109 static int alloc_channel_id(Ssh ssh)
1111 const unsigned CHANNEL_NUMBER_OFFSET = 256;
1112 unsigned low, high, mid;
1114 struct ssh_channel *c;
1117 * First-fit allocation of channel numbers: always pick the
1118 * lowest unused one. To do this, binary-search using the
1119 * counted B-tree to find the largest channel ID which is in a
1120 * contiguous sequence from the beginning. (Precisely
1121 * everything in that sequence must have ID equal to its tree
1122 * index plus CHANNEL_NUMBER_OFFSET.)
1124 tsize = count234(ssh->channels);
1128 while (high - low > 1) {
1129 mid = (high + low) / 2;
1130 c = index234(ssh->channels, mid);
1131 if (c->localid == mid + CHANNEL_NUMBER_OFFSET)
1132 low = mid; /* this one is fine */
1134 high = mid; /* this one is past it */
1137 * Now low points to either -1, or the tree index of the
1138 * largest ID in the initial sequence.
1141 unsigned i = low + 1 + CHANNEL_NUMBER_OFFSET;
1142 assert(NULL == find234(ssh->channels, &i, ssh_channelfind));
1144 return low + 1 + CHANNEL_NUMBER_OFFSET;
1147 static void c_write_stderr(int trusted, const char *buf, int len)
1150 for (i = 0; i < len; i++)
1151 if (buf[i] != '\r' && (trusted || buf[i] == '\n' || (buf[i] & 0x60)))
1152 fputc(buf[i], stderr);
1155 static void c_write(Ssh ssh, const char *buf, int len)
1157 if (flags & FLAG_STDERR)
1158 c_write_stderr(1, buf, len);
1160 from_backend(ssh->frontend, 1, buf, len);
1163 static void c_write_untrusted(Ssh ssh, const char *buf, int len)
1165 if (flags & FLAG_STDERR)
1166 c_write_stderr(0, buf, len);
1168 from_backend_untrusted(ssh->frontend, buf, len);
1171 static void c_write_str(Ssh ssh, const char *buf)
1173 c_write(ssh, buf, strlen(buf));
1176 static void ssh_free_packet(struct Packet *pkt)
1181 static struct Packet *ssh_new_packet(void)
1183 struct Packet *pkt = snew(struct Packet);
1185 pkt->body = pkt->data = NULL;
1191 static void ssh1_log_incoming_packet(Ssh ssh, struct Packet *pkt)
1194 struct logblank_t blanks[4];
1200 if (ssh->logomitdata &&
1201 (pkt->type == SSH1_SMSG_STDOUT_DATA ||
1202 pkt->type == SSH1_SMSG_STDERR_DATA ||
1203 pkt->type == SSH1_MSG_CHANNEL_DATA)) {
1204 /* "Session data" packets - omit the data string. */
1205 if (pkt->type == SSH1_MSG_CHANNEL_DATA)
1206 ssh_pkt_getuint32(pkt); /* skip channel id */
1207 blanks[nblanks].offset = pkt->savedpos + 4;
1208 blanks[nblanks].type = PKTLOG_OMIT;
1209 ssh_pkt_getstring(pkt, &str, &slen);
1211 blanks[nblanks].len = slen;
1215 log_packet(ssh->logctx, PKT_INCOMING, pkt->type,
1216 ssh1_pkt_type(pkt->type),
1217 pkt->body, pkt->length, nblanks, blanks, NULL,
1221 static void ssh1_log_outgoing_packet(Ssh ssh, struct Packet *pkt)
1224 struct logblank_t blanks[4];
1229 * For outgoing packets, pkt->length represents the length of the
1230 * whole packet starting at pkt->data (including some header), and
1231 * pkt->body refers to the point within that where the log-worthy
1232 * payload begins. However, incoming packets expect pkt->length to
1233 * represent only the payload length (that is, it's measured from
1234 * pkt->body not from pkt->data). Temporarily adjust our outgoing
1235 * packet to conform to the incoming-packet semantics, so that we
1236 * can analyse it with the ssh_pkt_get functions.
1238 pkt->length -= (pkt->body - pkt->data);
1241 if (ssh->logomitdata &&
1242 (pkt->type == SSH1_CMSG_STDIN_DATA ||
1243 pkt->type == SSH1_MSG_CHANNEL_DATA)) {
1244 /* "Session data" packets - omit the data string. */
1245 if (pkt->type == SSH1_MSG_CHANNEL_DATA)
1246 ssh_pkt_getuint32(pkt); /* skip channel id */
1247 blanks[nblanks].offset = pkt->savedpos + 4;
1248 blanks[nblanks].type = PKTLOG_OMIT;
1249 ssh_pkt_getstring(pkt, &str, &slen);
1251 blanks[nblanks].len = slen;
1256 if ((pkt->type == SSH1_CMSG_AUTH_PASSWORD ||
1257 pkt->type == SSH1_CMSG_AUTH_TIS_RESPONSE ||
1258 pkt->type == SSH1_CMSG_AUTH_CCARD_RESPONSE) &&
1259 conf_get_int(ssh->conf, CONF_logomitpass)) {
1260 /* If this is a password or similar packet, blank the password(s). */
1261 blanks[nblanks].offset = 0;
1262 blanks[nblanks].len = pkt->length;
1263 blanks[nblanks].type = PKTLOG_BLANK;
1265 } else if (pkt->type == SSH1_CMSG_X11_REQUEST_FORWARDING &&
1266 conf_get_int(ssh->conf, CONF_logomitpass)) {
1268 * If this is an X forwarding request packet, blank the fake
1271 * Note that while we blank the X authentication data here, we
1272 * don't take any special action to blank the start of an X11
1273 * channel, so using MIT-MAGIC-COOKIE-1 and actually opening
1274 * an X connection without having session blanking enabled is
1275 * likely to leak your cookie into the log.
1278 ssh_pkt_getstring(pkt, &str, &slen);
1279 blanks[nblanks].offset = pkt->savedpos;
1280 blanks[nblanks].type = PKTLOG_BLANK;
1281 ssh_pkt_getstring(pkt, &str, &slen);
1283 blanks[nblanks].len = pkt->savedpos - blanks[nblanks].offset;
1288 log_packet(ssh->logctx, PKT_OUTGOING, pkt->data[12],
1289 ssh1_pkt_type(pkt->data[12]),
1290 pkt->body, pkt->length,
1291 nblanks, blanks, NULL, 0, NULL);
1294 * Undo the above adjustment of pkt->length, to put the packet
1295 * back in the state we found it.
1297 pkt->length += (pkt->body - pkt->data);
1301 * Collect incoming data in the incoming packet buffer.
1302 * Decipher and verify the packet when it is completely read.
1303 * Drop SSH1_MSG_DEBUG and SSH1_MSG_IGNORE packets.
1304 * Update the *data and *datalen variables.
1305 * Return a Packet structure when a packet is completed.
1307 static struct Packet *ssh1_rdpkt(Ssh ssh, const unsigned char **data,
1310 struct rdpkt1_state_tag *st = &ssh->rdpkt1_state;
1312 crBegin(ssh->ssh1_rdpkt_crstate);
1314 st->pktin = ssh_new_packet();
1316 st->pktin->type = 0;
1317 st->pktin->length = 0;
1319 for (st->i = st->len = 0; st->i < 4; st->i++) {
1320 while ((*datalen) == 0)
1322 st->len = (st->len << 8) + **data;
1323 (*data)++, (*datalen)--;
1326 st->pad = 8 - (st->len % 8);
1327 st->biglen = st->len + st->pad;
1328 st->pktin->length = st->len - 5;
1330 if (st->biglen < 0) {
1331 bombout(("Extremely large packet length from server suggests"
1332 " data stream corruption"));
1333 ssh_free_packet(st->pktin);
1337 st->pktin->maxlen = st->biglen;
1338 st->pktin->data = snewn(st->biglen + APIEXTRA, unsigned char);
1340 st->to_read = st->biglen;
1341 st->p = st->pktin->data;
1342 while (st->to_read > 0) {
1343 st->chunk = st->to_read;
1344 while ((*datalen) == 0)
1346 if (st->chunk > (*datalen))
1347 st->chunk = (*datalen);
1348 memcpy(st->p, *data, st->chunk);
1350 *datalen -= st->chunk;
1352 st->to_read -= st->chunk;
1355 if (ssh->cipher && detect_attack(ssh->crcda_ctx, st->pktin->data,
1356 st->biglen, NULL)) {
1357 bombout(("Network attack (CRC compensation) detected!"));
1358 ssh_free_packet(st->pktin);
1363 ssh->cipher->decrypt(ssh->v1_cipher_ctx, st->pktin->data, st->biglen);
1365 st->realcrc = crc32_compute(st->pktin->data, st->biglen - 4);
1366 st->gotcrc = GET_32BIT(st->pktin->data + st->biglen - 4);
1367 if (st->gotcrc != st->realcrc) {
1368 bombout(("Incorrect CRC received on packet"));
1369 ssh_free_packet(st->pktin);
1373 st->pktin->body = st->pktin->data + st->pad + 1;
1375 if (ssh->v1_compressing) {
1376 unsigned char *decompblk;
1378 if (!zlib_decompress_block(ssh->sc_comp_ctx,
1379 st->pktin->body - 1, st->pktin->length + 1,
1380 &decompblk, &decomplen)) {
1381 bombout(("Zlib decompression encountered invalid data"));
1382 ssh_free_packet(st->pktin);
1386 if (st->pktin->maxlen < st->pad + decomplen) {
1387 st->pktin->maxlen = st->pad + decomplen;
1388 st->pktin->data = sresize(st->pktin->data,
1389 st->pktin->maxlen + APIEXTRA,
1391 st->pktin->body = st->pktin->data + st->pad + 1;
1394 memcpy(st->pktin->body - 1, decompblk, decomplen);
1396 st->pktin->length = decomplen - 1;
1399 st->pktin->type = st->pktin->body[-1];
1402 * Now pktin->body and pktin->length identify the semantic content
1403 * of the packet, excluding the initial type byte.
1407 ssh1_log_incoming_packet(ssh, st->pktin);
1409 st->pktin->savedpos = 0;
1411 crFinish(st->pktin);
1414 static void ssh2_log_incoming_packet(Ssh ssh, struct Packet *pkt)
1417 struct logblank_t blanks[4];
1423 if (ssh->logomitdata &&
1424 (pkt->type == SSH2_MSG_CHANNEL_DATA ||
1425 pkt->type == SSH2_MSG_CHANNEL_EXTENDED_DATA)) {
1426 /* "Session data" packets - omit the data string. */
1427 ssh_pkt_getuint32(pkt); /* skip channel id */
1428 if (pkt->type == SSH2_MSG_CHANNEL_EXTENDED_DATA)
1429 ssh_pkt_getuint32(pkt); /* skip extended data type */
1430 blanks[nblanks].offset = pkt->savedpos + 4;
1431 blanks[nblanks].type = PKTLOG_OMIT;
1432 ssh_pkt_getstring(pkt, &str, &slen);
1434 blanks[nblanks].len = slen;
1439 log_packet(ssh->logctx, PKT_INCOMING, pkt->type,
1440 ssh2_pkt_type(ssh->pkt_kctx, ssh->pkt_actx, pkt->type),
1441 pkt->body, pkt->length, nblanks, blanks, &pkt->sequence,
1445 static void ssh2_log_outgoing_packet(Ssh ssh, struct Packet *pkt)
1448 struct logblank_t blanks[4];
1453 * For outgoing packets, pkt->length represents the length of the
1454 * whole packet starting at pkt->data (including some header), and
1455 * pkt->body refers to the point within that where the log-worthy
1456 * payload begins. However, incoming packets expect pkt->length to
1457 * represent only the payload length (that is, it's measured from
1458 * pkt->body not from pkt->data). Temporarily adjust our outgoing
1459 * packet to conform to the incoming-packet semantics, so that we
1460 * can analyse it with the ssh_pkt_get functions.
1462 pkt->length -= (pkt->body - pkt->data);
1465 if (ssh->logomitdata &&
1466 (pkt->type == SSH2_MSG_CHANNEL_DATA ||
1467 pkt->type == SSH2_MSG_CHANNEL_EXTENDED_DATA)) {
1468 /* "Session data" packets - omit the data string. */
1469 ssh_pkt_getuint32(pkt); /* skip channel id */
1470 if (pkt->type == SSH2_MSG_CHANNEL_EXTENDED_DATA)
1471 ssh_pkt_getuint32(pkt); /* skip extended data type */
1472 blanks[nblanks].offset = pkt->savedpos + 4;
1473 blanks[nblanks].type = PKTLOG_OMIT;
1474 ssh_pkt_getstring(pkt, &str, &slen);
1476 blanks[nblanks].len = slen;
1481 if (pkt->type == SSH2_MSG_USERAUTH_REQUEST &&
1482 conf_get_int(ssh->conf, CONF_logomitpass)) {
1483 /* If this is a password packet, blank the password(s). */
1485 ssh_pkt_getstring(pkt, &str, &slen);
1486 ssh_pkt_getstring(pkt, &str, &slen);
1487 ssh_pkt_getstring(pkt, &str, &slen);
1488 if (slen == 8 && !memcmp(str, "password", 8)) {
1489 ssh2_pkt_getbool(pkt);
1490 /* Blank the password field. */
1491 blanks[nblanks].offset = pkt->savedpos;
1492 blanks[nblanks].type = PKTLOG_BLANK;
1493 ssh_pkt_getstring(pkt, &str, &slen);
1495 blanks[nblanks].len = pkt->savedpos - blanks[nblanks].offset;
1497 /* If there's another password field beyond it (change of
1498 * password), blank that too. */
1499 ssh_pkt_getstring(pkt, &str, &slen);
1501 blanks[nblanks-1].len =
1502 pkt->savedpos - blanks[nblanks].offset;
1505 } else if (ssh->pkt_actx == SSH2_PKTCTX_KBDINTER &&
1506 pkt->type == SSH2_MSG_USERAUTH_INFO_RESPONSE &&
1507 conf_get_int(ssh->conf, CONF_logomitpass)) {
1508 /* If this is a keyboard-interactive response packet, blank
1511 ssh_pkt_getuint32(pkt);
1512 blanks[nblanks].offset = pkt->savedpos;
1513 blanks[nblanks].type = PKTLOG_BLANK;
1515 ssh_pkt_getstring(pkt, &str, &slen);
1519 blanks[nblanks].len = pkt->savedpos - blanks[nblanks].offset;
1521 } else if (pkt->type == SSH2_MSG_CHANNEL_REQUEST &&
1522 conf_get_int(ssh->conf, CONF_logomitpass)) {
1524 * If this is an X forwarding request packet, blank the fake
1527 * Note that while we blank the X authentication data here, we
1528 * don't take any special action to blank the start of an X11
1529 * channel, so using MIT-MAGIC-COOKIE-1 and actually opening
1530 * an X connection without having session blanking enabled is
1531 * likely to leak your cookie into the log.
1534 ssh_pkt_getuint32(pkt);
1535 ssh_pkt_getstring(pkt, &str, &slen);
1536 if (slen == 7 && !memcmp(str, "x11-req", 0)) {
1537 ssh2_pkt_getbool(pkt);
1538 ssh2_pkt_getbool(pkt);
1539 ssh_pkt_getstring(pkt, &str, &slen);
1540 blanks[nblanks].offset = pkt->savedpos;
1541 blanks[nblanks].type = PKTLOG_BLANK;
1542 ssh_pkt_getstring(pkt, &str, &slen);
1544 blanks[nblanks].len = pkt->savedpos - blanks[nblanks].offset;
1550 log_packet(ssh->logctx, PKT_OUTGOING, pkt->data[5],
1551 ssh2_pkt_type(ssh->pkt_kctx, ssh->pkt_actx, pkt->data[5]),
1552 pkt->body, pkt->length, nblanks, blanks,
1553 &ssh->v2_outgoing_sequence,
1554 pkt->downstream_id, pkt->additional_log_text);
1557 * Undo the above adjustment of pkt->length, to put the packet
1558 * back in the state we found it.
1560 pkt->length += (pkt->body - pkt->data);
1563 static struct Packet *ssh2_rdpkt(Ssh ssh, const unsigned char **data,
1566 struct rdpkt2_state_tag *st = &ssh->rdpkt2_state;
1568 crBegin(ssh->ssh2_rdpkt_crstate);
1570 st->pktin = ssh_new_packet();
1572 st->pktin->type = 0;
1573 st->pktin->length = 0;
1575 st->cipherblk = ssh->sccipher->blksize;
1578 if (st->cipherblk < 8)
1580 st->maclen = ssh->scmac ? ssh->scmac->len : 0;
1582 if (ssh->sccipher && (ssh->sccipher->flags & SSH_CIPHER_IS_CBC) &&
1583 ssh->scmac && !ssh->scmac_etm) {
1585 * When dealing with a CBC-mode cipher, we want to avoid the
1586 * possibility of an attacker's tweaking the ciphertext stream
1587 * so as to cause us to feed the same block to the block
1588 * cipher more than once and thus leak information
1589 * (VU#958563). The way we do this is not to take any
1590 * decisions on the basis of anything we've decrypted until
1591 * we've verified it with a MAC. That includes the packet
1592 * length, so we just read data and check the MAC repeatedly,
1593 * and when the MAC passes, see if the length we've got is
1596 * This defence is unnecessary in OpenSSH ETM mode, because
1597 * the whole point of ETM mode is that the attacker can't
1598 * tweak the ciphertext stream at all without the MAC
1599 * detecting it before we decrypt anything.
1602 /* May as well allocate the whole lot now. */
1603 st->pktin->data = snewn(OUR_V2_PACKETLIMIT + st->maclen + APIEXTRA,
1606 /* Read an amount corresponding to the MAC. */
1607 for (st->i = 0; st->i < st->maclen; st->i++) {
1608 while ((*datalen) == 0)
1610 st->pktin->data[st->i] = *(*data)++;
1616 unsigned char seq[4];
1617 ssh->scmac->start(ssh->sc_mac_ctx);
1618 PUT_32BIT(seq, st->incoming_sequence);
1619 ssh->scmac->bytes(ssh->sc_mac_ctx, seq, 4);
1622 for (;;) { /* Once around this loop per cipher block. */
1623 /* Read another cipher-block's worth, and tack it onto the end. */
1624 for (st->i = 0; st->i < st->cipherblk; st->i++) {
1625 while ((*datalen) == 0)
1627 st->pktin->data[st->packetlen+st->maclen+st->i] = *(*data)++;
1630 /* Decrypt one more block (a little further back in the stream). */
1631 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
1632 st->pktin->data + st->packetlen,
1634 /* Feed that block to the MAC. */
1635 ssh->scmac->bytes(ssh->sc_mac_ctx,
1636 st->pktin->data + st->packetlen, st->cipherblk);
1637 st->packetlen += st->cipherblk;
1638 /* See if that gives us a valid packet. */
1639 if (ssh->scmac->verresult(ssh->sc_mac_ctx,
1640 st->pktin->data + st->packetlen) &&
1641 ((st->len = toint(GET_32BIT(st->pktin->data))) ==
1644 if (st->packetlen >= OUR_V2_PACKETLIMIT) {
1645 bombout(("No valid incoming packet found"));
1646 ssh_free_packet(st->pktin);
1650 st->pktin->maxlen = st->packetlen + st->maclen;
1651 st->pktin->data = sresize(st->pktin->data,
1652 st->pktin->maxlen + APIEXTRA,
1654 } else if (ssh->scmac && ssh->scmac_etm) {
1655 st->pktin->data = snewn(4 + APIEXTRA, unsigned char);
1658 * OpenSSH encrypt-then-MAC mode: the packet length is
1659 * unencrypted, unless the cipher supports length encryption.
1661 for (st->i = st->len = 0; st->i < 4; st->i++) {
1662 while ((*datalen) == 0)
1664 st->pktin->data[st->i] = *(*data)++;
1667 /* Cipher supports length decryption, so do it */
1668 if (ssh->sccipher && (ssh->sccipher->flags & SSH_CIPHER_SEPARATE_LENGTH)) {
1669 /* Keep the packet the same though, so the MAC passes */
1670 unsigned char len[4];
1671 memcpy(len, st->pktin->data, 4);
1672 ssh->sccipher->decrypt_length(ssh->sc_cipher_ctx, len, 4, st->incoming_sequence);
1673 st->len = toint(GET_32BIT(len));
1675 st->len = toint(GET_32BIT(st->pktin->data));
1679 * _Completely_ silly lengths should be stomped on before they
1680 * do us any more damage.
1682 if (st->len < 0 || st->len > OUR_V2_PACKETLIMIT ||
1683 st->len % st->cipherblk != 0) {
1684 bombout(("Incoming packet length field was garbled"));
1685 ssh_free_packet(st->pktin);
1690 * So now we can work out the total packet length.
1692 st->packetlen = st->len + 4;
1695 * Allocate memory for the rest of the packet.
1697 st->pktin->maxlen = st->packetlen + st->maclen;
1698 st->pktin->data = sresize(st->pktin->data,
1699 st->pktin->maxlen + APIEXTRA,
1703 * Read the remainder of the packet.
1705 for (st->i = 4; st->i < st->packetlen + st->maclen; st->i++) {
1706 while ((*datalen) == 0)
1708 st->pktin->data[st->i] = *(*data)++;
1716 && !ssh->scmac->verify(ssh->sc_mac_ctx, st->pktin->data,
1717 st->len + 4, st->incoming_sequence)) {
1718 bombout(("Incorrect MAC received on packet"));
1719 ssh_free_packet(st->pktin);
1723 /* Decrypt everything between the length field and the MAC. */
1725 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
1726 st->pktin->data + 4,
1729 st->pktin->data = snewn(st->cipherblk + APIEXTRA, unsigned char);
1732 * Acquire and decrypt the first block of the packet. This will
1733 * contain the length and padding details.
1735 for (st->i = st->len = 0; st->i < st->cipherblk; st->i++) {
1736 while ((*datalen) == 0)
1738 st->pktin->data[st->i] = *(*data)++;
1743 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
1744 st->pktin->data, st->cipherblk);
1747 * Now get the length figure.
1749 st->len = toint(GET_32BIT(st->pktin->data));
1752 * _Completely_ silly lengths should be stomped on before they
1753 * do us any more damage.
1755 if (st->len < 0 || st->len > OUR_V2_PACKETLIMIT ||
1756 (st->len + 4) % st->cipherblk != 0) {
1757 bombout(("Incoming packet was garbled on decryption"));
1758 ssh_free_packet(st->pktin);
1763 * So now we can work out the total packet length.
1765 st->packetlen = st->len + 4;
1768 * Allocate memory for the rest of the packet.
1770 st->pktin->maxlen = st->packetlen + st->maclen;
1771 st->pktin->data = sresize(st->pktin->data,
1772 st->pktin->maxlen + APIEXTRA,
1776 * Read and decrypt the remainder of the packet.
1778 for (st->i = st->cipherblk; st->i < st->packetlen + st->maclen;
1780 while ((*datalen) == 0)
1782 st->pktin->data[st->i] = *(*data)++;
1785 /* Decrypt everything _except_ the MAC. */
1787 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
1788 st->pktin->data + st->cipherblk,
1789 st->packetlen - st->cipherblk);
1795 && !ssh->scmac->verify(ssh->sc_mac_ctx, st->pktin->data,
1796 st->len + 4, st->incoming_sequence)) {
1797 bombout(("Incorrect MAC received on packet"));
1798 ssh_free_packet(st->pktin);
1802 /* Get and sanity-check the amount of random padding. */
1803 st->pad = st->pktin->data[4];
1804 if (st->pad < 4 || st->len - st->pad < 1) {
1805 bombout(("Invalid padding length on received packet"));
1806 ssh_free_packet(st->pktin);
1810 * This enables us to deduce the payload length.
1812 st->payload = st->len - st->pad - 1;
1814 st->pktin->length = st->payload + 5;
1815 st->pktin->encrypted_len = st->packetlen;
1817 st->pktin->sequence = st->incoming_sequence++;
1819 st->pktin->length = st->packetlen - st->pad;
1820 assert(st->pktin->length >= 0);
1823 * Decompress packet payload.
1826 unsigned char *newpayload;
1829 ssh->sccomp->decompress(ssh->sc_comp_ctx,
1830 st->pktin->data + 5, st->pktin->length - 5,
1831 &newpayload, &newlen)) {
1832 if (st->pktin->maxlen < newlen + 5) {
1833 st->pktin->maxlen = newlen + 5;
1834 st->pktin->data = sresize(st->pktin->data,
1835 st->pktin->maxlen + APIEXTRA,
1838 st->pktin->length = 5 + newlen;
1839 memcpy(st->pktin->data + 5, newpayload, newlen);
1845 * RFC 4253 doesn't explicitly say that completely empty packets
1846 * with no type byte are forbidden, so treat them as deserving
1847 * an SSH_MSG_UNIMPLEMENTED.
1849 if (st->pktin->length <= 5) { /* == 5 we hope, but robustness */
1850 ssh2_msg_something_unimplemented(ssh, st->pktin);
1854 * pktin->body and pktin->length should identify the semantic
1855 * content of the packet, excluding the initial type byte.
1857 st->pktin->type = st->pktin->data[5];
1858 st->pktin->body = st->pktin->data + 6;
1859 st->pktin->length -= 6;
1860 assert(st->pktin->length >= 0); /* one last double-check */
1863 ssh2_log_incoming_packet(ssh, st->pktin);
1865 st->pktin->savedpos = 0;
1867 crFinish(st->pktin);
1870 static struct Packet *ssh2_bare_connection_rdpkt(Ssh ssh,
1871 const unsigned char **data,
1874 struct rdpkt2_bare_state_tag *st = &ssh->rdpkt2_bare_state;
1876 crBegin(ssh->ssh2_bare_rdpkt_crstate);
1879 * Read the packet length field.
1881 for (st->i = 0; st->i < 4; st->i++) {
1882 while ((*datalen) == 0)
1884 st->length[st->i] = *(*data)++;
1888 st->packetlen = toint(GET_32BIT_MSB_FIRST(st->length));
1889 if (st->packetlen <= 0 || st->packetlen >= OUR_V2_PACKETLIMIT) {
1890 bombout(("Invalid packet length received"));
1894 st->pktin = ssh_new_packet();
1895 st->pktin->data = snewn(st->packetlen, unsigned char);
1897 st->pktin->encrypted_len = st->packetlen;
1899 st->pktin->sequence = st->incoming_sequence++;
1902 * Read the remainder of the packet.
1904 for (st->i = 0; st->i < st->packetlen; st->i++) {
1905 while ((*datalen) == 0)
1907 st->pktin->data[st->i] = *(*data)++;
1912 * pktin->body and pktin->length should identify the semantic
1913 * content of the packet, excluding the initial type byte.
1915 st->pktin->type = st->pktin->data[0];
1916 st->pktin->body = st->pktin->data + 1;
1917 st->pktin->length = st->packetlen - 1;
1920 * Log incoming packet, possibly omitting sensitive fields.
1923 ssh2_log_incoming_packet(ssh, st->pktin);
1925 st->pktin->savedpos = 0;
1927 crFinish(st->pktin);
1930 static int s_wrpkt_prepare(Ssh ssh, struct Packet *pkt, int *offset_p)
1932 int pad, biglen, i, pktoffs;
1936 * XXX various versions of SC (including 8.8.4) screw up the
1937 * register allocation in this function and use the same register
1938 * (D6) for len and as a temporary, with predictable results. The
1939 * following sledgehammer prevents this.
1946 ssh1_log_outgoing_packet(ssh, pkt);
1948 if (ssh->v1_compressing) {
1949 unsigned char *compblk;
1951 zlib_compress_block(ssh->cs_comp_ctx,
1952 pkt->data + 12, pkt->length - 12,
1953 &compblk, &complen);
1954 ssh_pkt_ensure(pkt, complen + 2); /* just in case it's got bigger */
1955 memcpy(pkt->data + 12, compblk, complen);
1957 pkt->length = complen + 12;
1960 ssh_pkt_ensure(pkt, pkt->length + 4); /* space for CRC */
1962 len = pkt->length - 4 - 8; /* len(type+data+CRC) */
1963 pad = 8 - (len % 8);
1965 biglen = len + pad; /* len(padding+type+data+CRC) */
1967 for (i = pktoffs; i < 4+8; i++)
1968 pkt->data[i] = random_byte();
1969 crc = crc32_compute(pkt->data + pktoffs + 4, biglen - 4); /* all ex len */
1970 PUT_32BIT(pkt->data + pktoffs + 4 + biglen - 4, crc);
1971 PUT_32BIT(pkt->data + pktoffs, len);
1974 ssh->cipher->encrypt(ssh->v1_cipher_ctx,
1975 pkt->data + pktoffs + 4, biglen);
1977 if (offset_p) *offset_p = pktoffs;
1978 return biglen + 4; /* len(length+padding+type+data+CRC) */
1981 static int s_write(Ssh ssh, void *data, int len)
1984 log_packet(ssh->logctx, PKT_OUTGOING, -1, NULL, data, len,
1985 0, NULL, NULL, 0, NULL);
1988 return sk_write(ssh->s, (char *)data, len);
1991 static void s_wrpkt(Ssh ssh, struct Packet *pkt)
1993 int len, backlog, offset;
1994 len = s_wrpkt_prepare(ssh, pkt, &offset);
1995 backlog = s_write(ssh, pkt->data + offset, len);
1996 if (backlog > SSH_MAX_BACKLOG)
1997 ssh_throttle_all(ssh, 1, backlog);
1998 ssh_free_packet(pkt);
2001 static void s_wrpkt_defer(Ssh ssh, struct Packet *pkt)
2004 len = s_wrpkt_prepare(ssh, pkt, &offset);
2005 if (ssh->deferred_len + len > ssh->deferred_size) {
2006 ssh->deferred_size = ssh->deferred_len + len + 128;
2007 ssh->deferred_send_data = sresize(ssh->deferred_send_data,
2011 memcpy(ssh->deferred_send_data + ssh->deferred_len,
2012 pkt->data + offset, len);
2013 ssh->deferred_len += len;
2014 ssh_free_packet(pkt);
2018 * Construct a SSH-1 packet with the specified contents.
2019 * (This all-at-once interface used to be the only one, but now SSH-1
2020 * packets can also be constructed incrementally.)
2022 static struct Packet *construct_packet(Ssh ssh, int pkttype, va_list ap)
2028 pkt = ssh1_pkt_init(pkttype);
2030 while ((argtype = va_arg(ap, int)) != PKT_END) {
2031 unsigned char *argp, argchar;
2033 unsigned long argint;
2036 /* Actual fields in the packet */
2038 argint = va_arg(ap, int);
2039 ssh_pkt_adduint32(pkt, argint);
2042 argchar = (unsigned char) va_arg(ap, int);
2043 ssh_pkt_addbyte(pkt, argchar);
2046 argp = va_arg(ap, unsigned char *);
2047 arglen = va_arg(ap, int);
2048 ssh_pkt_adddata(pkt, argp, arglen);
2051 sargp = va_arg(ap, char *);
2052 ssh_pkt_addstring(pkt, sargp);
2055 bn = va_arg(ap, Bignum);
2056 ssh1_pkt_addmp(pkt, bn);
2064 static void send_packet(Ssh ssh, int pkttype, ...)
2068 va_start(ap, pkttype);
2069 pkt = construct_packet(ssh, pkttype, ap);
2074 static void defer_packet(Ssh ssh, int pkttype, ...)
2078 va_start(ap, pkttype);
2079 pkt = construct_packet(ssh, pkttype, ap);
2081 s_wrpkt_defer(ssh, pkt);
2084 static int ssh_versioncmp(const char *a, const char *b)
2087 unsigned long av, bv;
2089 av = strtoul(a, &ae, 10);
2090 bv = strtoul(b, &be, 10);
2092 return (av < bv ? -1 : +1);
2097 av = strtoul(ae, &ae, 10);
2098 bv = strtoul(be, &be, 10);
2100 return (av < bv ? -1 : +1);
2105 * Utility routines for putting an SSH-protocol `string' and
2106 * `uint32' into a hash state.
2108 static void hash_string(const struct ssh_hash *h, void *s, void *str, int len)
2110 unsigned char lenblk[4];
2111 PUT_32BIT(lenblk, len);
2112 h->bytes(s, lenblk, 4);
2113 h->bytes(s, str, len);
2116 static void hash_uint32(const struct ssh_hash *h, void *s, unsigned i)
2118 unsigned char intblk[4];
2119 PUT_32BIT(intblk, i);
2120 h->bytes(s, intblk, 4);
2124 * Packet construction functions. Mostly shared between SSH-1 and SSH-2.
2126 static void ssh_pkt_ensure(struct Packet *pkt, int length)
2128 if (pkt->maxlen < length) {
2129 unsigned char *body = pkt->body;
2130 int offset = body ? body - pkt->data : 0;
2131 pkt->maxlen = length + 256;
2132 pkt->data = sresize(pkt->data, pkt->maxlen + APIEXTRA, unsigned char);
2133 if (body) pkt->body = pkt->data + offset;
2136 static void ssh_pkt_adddata(struct Packet *pkt, const void *data, int len)
2139 ssh_pkt_ensure(pkt, pkt->length);
2140 memcpy(pkt->data + pkt->length - len, data, len);
2142 static void ssh_pkt_addbyte(struct Packet *pkt, unsigned char byte)
2144 ssh_pkt_adddata(pkt, &byte, 1);
2146 static void ssh2_pkt_addbool(struct Packet *pkt, unsigned char value)
2148 ssh_pkt_adddata(pkt, &value, 1);
2150 static void ssh_pkt_adduint32(struct Packet *pkt, unsigned long value)
2153 PUT_32BIT(x, value);
2154 ssh_pkt_adddata(pkt, x, 4);
2156 static void ssh_pkt_addstring_start(struct Packet *pkt)
2158 ssh_pkt_adduint32(pkt, 0);
2159 pkt->savedpos = pkt->length;
2161 static void ssh_pkt_addstring_data(struct Packet *pkt, const char *data,
2164 ssh_pkt_adddata(pkt, data, len);
2165 PUT_32BIT(pkt->data + pkt->savedpos - 4, pkt->length - pkt->savedpos);
2167 static void ssh_pkt_addstring_str(struct Packet *pkt, const char *data)
2169 ssh_pkt_addstring_data(pkt, data, strlen(data));
2171 static void ssh_pkt_addstring(struct Packet *pkt, const char *data)
2173 ssh_pkt_addstring_start(pkt);
2174 ssh_pkt_addstring_str(pkt, data);
2176 static void ssh1_pkt_addmp(struct Packet *pkt, Bignum b)
2178 int len = ssh1_bignum_length(b);
2179 unsigned char *data = snewn(len, unsigned char);
2180 (void) ssh1_write_bignum(data, b);
2181 ssh_pkt_adddata(pkt, data, len);
2184 static unsigned char *ssh2_mpint_fmt(Bignum b, int *len)
2187 int i, n = (bignum_bitcount(b) + 7) / 8;
2188 p = snewn(n + 1, unsigned char);
2190 for (i = 1; i <= n; i++)
2191 p[i] = bignum_byte(b, n - i);
2193 while (i <= n && p[i] == 0 && (p[i + 1] & 0x80) == 0)
2195 memmove(p, p + i, n + 1 - i);
2199 static void ssh2_pkt_addmp(struct Packet *pkt, Bignum b)
2203 p = ssh2_mpint_fmt(b, &len);
2204 ssh_pkt_addstring_start(pkt);
2205 ssh_pkt_addstring_data(pkt, (char *)p, len);
2209 static struct Packet *ssh1_pkt_init(int pkt_type)
2211 struct Packet *pkt = ssh_new_packet();
2212 pkt->length = 4 + 8; /* space for length + max padding */
2213 ssh_pkt_addbyte(pkt, pkt_type);
2214 pkt->body = pkt->data + pkt->length;
2215 pkt->type = pkt_type;
2216 pkt->downstream_id = 0;
2217 pkt->additional_log_text = NULL;
2221 /* For legacy code (SSH-1 and -2 packet construction used to be separate) */
2222 #define ssh2_pkt_ensure(pkt, length) ssh_pkt_ensure(pkt, length)
2223 #define ssh2_pkt_adddata(pkt, data, len) ssh_pkt_adddata(pkt, data, len)
2224 #define ssh2_pkt_addbyte(pkt, byte) ssh_pkt_addbyte(pkt, byte)
2225 #define ssh2_pkt_adduint32(pkt, value) ssh_pkt_adduint32(pkt, value)
2226 #define ssh2_pkt_addstring_start(pkt) ssh_pkt_addstring_start(pkt)
2227 #define ssh2_pkt_addstring_str(pkt, data) ssh_pkt_addstring_str(pkt, data)
2228 #define ssh2_pkt_addstring_data(pkt, data, len) ssh_pkt_addstring_data(pkt, data, len)
2229 #define ssh2_pkt_addstring(pkt, data) ssh_pkt_addstring(pkt, data)
2231 static struct Packet *ssh2_pkt_init(int pkt_type)
2233 struct Packet *pkt = ssh_new_packet();
2234 pkt->length = 5; /* space for packet length + padding length */
2236 pkt->type = pkt_type;
2237 ssh_pkt_addbyte(pkt, (unsigned char) pkt_type);
2238 pkt->body = pkt->data + pkt->length; /* after packet type */
2239 pkt->downstream_id = 0;
2240 pkt->additional_log_text = NULL;
2245 * Construct an SSH-2 final-form packet: compress it, encrypt it,
2246 * put the MAC on it. Final packet, ready to be sent, is stored in
2247 * pkt->data. Total length is returned.
2249 static int ssh2_pkt_construct(Ssh ssh, struct Packet *pkt)
2251 int cipherblk, maclen, padding, unencrypted_prefix, i;
2254 ssh2_log_outgoing_packet(ssh, pkt);
2256 if (ssh->bare_connection) {
2258 * Trivial packet construction for the bare connection
2261 PUT_32BIT(pkt->data + 1, pkt->length - 5);
2262 pkt->body = pkt->data + 1;
2263 ssh->v2_outgoing_sequence++; /* only for diagnostics, really */
2264 return pkt->length - 1;
2268 * Compress packet payload.
2271 unsigned char *newpayload;
2274 ssh->cscomp->compress(ssh->cs_comp_ctx, pkt->data + 5,
2276 &newpayload, &newlen)) {
2278 ssh2_pkt_adddata(pkt, newpayload, newlen);
2284 * Add padding. At least four bytes, and must also bring total
2285 * length (minus MAC) up to a multiple of the block size.
2286 * If pkt->forcepad is set, make sure the packet is at least that size
2289 cipherblk = ssh->cscipher ? ssh->cscipher->blksize : 8; /* block size */
2290 cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */
2292 unencrypted_prefix = (ssh->csmac && ssh->csmac_etm) ? 4 : 0;
2293 if (pkt->length + padding < pkt->forcepad)
2294 padding = pkt->forcepad - pkt->length;
2296 (cipherblk - (pkt->length - unencrypted_prefix + padding) % cipherblk)
2298 assert(padding <= 255);
2299 maclen = ssh->csmac ? ssh->csmac->len : 0;
2300 ssh2_pkt_ensure(pkt, pkt->length + padding + maclen);
2301 pkt->data[4] = padding;
2302 for (i = 0; i < padding; i++)
2303 pkt->data[pkt->length + i] = random_byte();
2304 PUT_32BIT(pkt->data, pkt->length + padding - 4);
2306 /* Encrypt length if the scheme requires it */
2307 if (ssh->cscipher && (ssh->cscipher->flags & SSH_CIPHER_SEPARATE_LENGTH)) {
2308 ssh->cscipher->encrypt_length(ssh->cs_cipher_ctx, pkt->data, 4,
2309 ssh->v2_outgoing_sequence);
2312 if (ssh->csmac && ssh->csmac_etm) {
2314 * OpenSSH-defined encrypt-then-MAC protocol.
2317 ssh->cscipher->encrypt(ssh->cs_cipher_ctx,
2318 pkt->data + 4, pkt->length + padding - 4);
2319 ssh->csmac->generate(ssh->cs_mac_ctx, pkt->data,
2320 pkt->length + padding,
2321 ssh->v2_outgoing_sequence);
2324 * SSH-2 standard protocol.
2327 ssh->csmac->generate(ssh->cs_mac_ctx, pkt->data,
2328 pkt->length + padding,
2329 ssh->v2_outgoing_sequence);
2331 ssh->cscipher->encrypt(ssh->cs_cipher_ctx,
2332 pkt->data, pkt->length + padding);
2335 ssh->v2_outgoing_sequence++; /* whether or not we MACed */
2336 pkt->encrypted_len = pkt->length + padding;
2338 /* Ready-to-send packet starts at pkt->data. We return length. */
2339 pkt->body = pkt->data;
2340 return pkt->length + padding + maclen;
2344 * Routines called from the main SSH code to send packets. There
2345 * are quite a few of these, because we have two separate
2346 * mechanisms for delaying the sending of packets:
2348 * - In order to send an IGNORE message and a password message in
2349 * a single fixed-length blob, we require the ability to
2350 * concatenate the encrypted forms of those two packets _into_ a
2351 * single blob and then pass it to our <network.h> transport
2352 * layer in one go. Hence, there's a deferment mechanism which
2353 * works after packet encryption.
2355 * - In order to avoid sending any connection-layer messages
2356 * during repeat key exchange, we have to queue up any such
2357 * outgoing messages _before_ they are encrypted (and in
2358 * particular before they're allocated sequence numbers), and
2359 * then send them once we've finished.
2361 * I call these mechanisms `defer' and `queue' respectively, so as
2362 * to distinguish them reasonably easily.
2364 * The functions send_noqueue() and defer_noqueue() free the packet
2365 * structure they are passed. Every outgoing packet goes through
2366 * precisely one of these functions in its life; packets passed to
2367 * ssh2_pkt_send() or ssh2_pkt_defer() either go straight to one of
2368 * these or get queued, and then when the queue is later emptied
2369 * the packets are all passed to defer_noqueue().
2371 * When using a CBC-mode cipher, it's necessary to ensure that an
2372 * attacker can't provide data to be encrypted using an IV that they
2373 * know. We ensure this by prefixing each packet that might contain
2374 * user data with an SSH_MSG_IGNORE. This is done using the deferral
2375 * mechanism, so in this case send_noqueue() ends up redirecting to
2376 * defer_noqueue(). If you don't like this inefficiency, don't use
2380 static void ssh2_pkt_defer_noqueue(Ssh, struct Packet *, int);
2381 static void ssh_pkt_defersend(Ssh);
2384 * Send an SSH-2 packet immediately, without queuing or deferring.
2386 static void ssh2_pkt_send_noqueue(Ssh ssh, struct Packet *pkt)
2390 if (ssh->cscipher != NULL && (ssh->cscipher->flags & SSH_CIPHER_IS_CBC)) {
2391 /* We need to send two packets, so use the deferral mechanism. */
2392 ssh2_pkt_defer_noqueue(ssh, pkt, FALSE);
2393 ssh_pkt_defersend(ssh);
2396 len = ssh2_pkt_construct(ssh, pkt);
2397 backlog = s_write(ssh, pkt->body, len);
2398 if (backlog > SSH_MAX_BACKLOG)
2399 ssh_throttle_all(ssh, 1, backlog);
2401 ssh->outgoing_data_size += pkt->encrypted_len;
2402 if (!ssh->kex_in_progress &&
2403 !ssh->bare_connection &&
2404 ssh->max_data_size != 0 &&
2405 ssh->outgoing_data_size > ssh->max_data_size)
2406 do_ssh2_transport(ssh, "too much data sent", -1, NULL);
2408 ssh_free_packet(pkt);
2412 * Defer an SSH-2 packet.
2414 static void ssh2_pkt_defer_noqueue(Ssh ssh, struct Packet *pkt, int noignore)
2417 if (ssh->cscipher != NULL && (ssh->cscipher->flags & SSH_CIPHER_IS_CBC) &&
2418 ssh->deferred_len == 0 && !noignore &&
2419 !(ssh->remote_bugs & BUG_CHOKES_ON_SSH2_IGNORE)) {
2421 * Interpose an SSH_MSG_IGNORE to ensure that user data don't
2422 * get encrypted with a known IV.
2424 struct Packet *ipkt = ssh2_pkt_init(SSH2_MSG_IGNORE);
2425 ssh2_pkt_addstring_start(ipkt);
2426 ssh2_pkt_defer_noqueue(ssh, ipkt, TRUE);
2428 len = ssh2_pkt_construct(ssh, pkt);
2429 if (ssh->deferred_len + len > ssh->deferred_size) {
2430 ssh->deferred_size = ssh->deferred_len + len + 128;
2431 ssh->deferred_send_data = sresize(ssh->deferred_send_data,
2435 memcpy(ssh->deferred_send_data + ssh->deferred_len, pkt->body, len);
2436 ssh->deferred_len += len;
2437 ssh->deferred_data_size += pkt->encrypted_len;
2438 ssh_free_packet(pkt);
2442 * Queue an SSH-2 packet.
2444 static void ssh2_pkt_queue(Ssh ssh, struct Packet *pkt)
2446 assert(ssh->queueing);
2448 if (ssh->queuelen >= ssh->queuesize) {
2449 ssh->queuesize = ssh->queuelen + 32;
2450 ssh->queue = sresize(ssh->queue, ssh->queuesize, struct Packet *);
2453 ssh->queue[ssh->queuelen++] = pkt;
2457 * Either queue or send a packet, depending on whether queueing is
2460 static void ssh2_pkt_send(Ssh ssh, struct Packet *pkt)
2463 ssh2_pkt_queue(ssh, pkt);
2465 ssh2_pkt_send_noqueue(ssh, pkt);
2469 * Either queue or defer a packet, depending on whether queueing is
2472 static void ssh2_pkt_defer(Ssh ssh, struct Packet *pkt)
2475 ssh2_pkt_queue(ssh, pkt);
2477 ssh2_pkt_defer_noqueue(ssh, pkt, FALSE);
2481 * Send the whole deferred data block constructed by
2482 * ssh2_pkt_defer() or SSH-1's defer_packet().
2484 * The expected use of the defer mechanism is that you call
2485 * ssh2_pkt_defer() a few times, then call ssh_pkt_defersend(). If
2486 * not currently queueing, this simply sets up deferred_send_data
2487 * and then sends it. If we _are_ currently queueing, the calls to
2488 * ssh2_pkt_defer() put the deferred packets on to the queue
2489 * instead, and therefore ssh_pkt_defersend() has no deferred data
2490 * to send. Hence, there's no need to make it conditional on
2493 static void ssh_pkt_defersend(Ssh ssh)
2496 backlog = s_write(ssh, ssh->deferred_send_data, ssh->deferred_len);
2497 ssh->deferred_len = ssh->deferred_size = 0;
2498 sfree(ssh->deferred_send_data);
2499 ssh->deferred_send_data = NULL;
2500 if (backlog > SSH_MAX_BACKLOG)
2501 ssh_throttle_all(ssh, 1, backlog);
2503 ssh->outgoing_data_size += ssh->deferred_data_size;
2504 if (!ssh->kex_in_progress &&
2505 !ssh->bare_connection &&
2506 ssh->max_data_size != 0 &&
2507 ssh->outgoing_data_size > ssh->max_data_size)
2508 do_ssh2_transport(ssh, "too much data sent", -1, NULL);
2509 ssh->deferred_data_size = 0;
2513 * Send a packet whose length needs to be disguised (typically
2514 * passwords or keyboard-interactive responses).
2516 static void ssh2_pkt_send_with_padding(Ssh ssh, struct Packet *pkt,
2522 * The simplest way to do this is to adjust the
2523 * variable-length padding field in the outgoing packet.
2525 * Currently compiled out, because some Cisco SSH servers
2526 * don't like excessively padded packets (bah, why's it
2529 pkt->forcepad = padsize;
2530 ssh2_pkt_send(ssh, pkt);
2535 * If we can't do that, however, an alternative approach is
2536 * to use the pkt_defer mechanism to bundle the packet
2537 * tightly together with an SSH_MSG_IGNORE such that their
2538 * combined length is a constant. So first we construct the
2539 * final form of this packet and defer its sending.
2541 ssh2_pkt_defer(ssh, pkt);
2544 * Now construct an SSH_MSG_IGNORE which includes a string
2545 * that's an exact multiple of the cipher block size. (If
2546 * the cipher is NULL so that the block size is
2547 * unavailable, we don't do this trick at all, because we
2548 * gain nothing by it.)
2550 if (ssh->cscipher &&
2551 !(ssh->remote_bugs & BUG_CHOKES_ON_SSH2_IGNORE)) {
2554 stringlen = (256 - ssh->deferred_len);
2555 stringlen += ssh->cscipher->blksize - 1;
2556 stringlen -= (stringlen % ssh->cscipher->blksize);
2559 * Temporarily disable actual compression, so we
2560 * can guarantee to get this string exactly the
2561 * length we want it. The compression-disabling
2562 * routine should return an integer indicating how
2563 * many bytes we should adjust our string length
2567 ssh->cscomp->disable_compression(ssh->cs_comp_ctx);
2569 pkt = ssh2_pkt_init(SSH2_MSG_IGNORE);
2570 ssh2_pkt_addstring_start(pkt);
2571 for (i = 0; i < stringlen; i++) {
2572 char c = (char) random_byte();
2573 ssh2_pkt_addstring_data(pkt, &c, 1);
2575 ssh2_pkt_defer(ssh, pkt);
2577 ssh_pkt_defersend(ssh);
2582 * Send all queued SSH-2 packets. We send them by means of
2583 * ssh2_pkt_defer_noqueue(), in case they included a pair of
2584 * packets that needed to be lumped together.
2586 static void ssh2_pkt_queuesend(Ssh ssh)
2590 assert(!ssh->queueing);
2592 for (i = 0; i < ssh->queuelen; i++)
2593 ssh2_pkt_defer_noqueue(ssh, ssh->queue[i], FALSE);
2596 ssh_pkt_defersend(ssh);
2600 void bndebug(char *string, Bignum b)
2604 p = ssh2_mpint_fmt(b, &len);
2605 debug(("%s", string));
2606 for (i = 0; i < len; i++)
2607 debug((" %02x", p[i]));
2613 static void hash_mpint(const struct ssh_hash *h, void *s, Bignum b)
2617 p = ssh2_mpint_fmt(b, &len);
2618 hash_string(h, s, p, len);
2623 * Packet decode functions for both SSH-1 and SSH-2.
2625 static unsigned long ssh_pkt_getuint32(struct Packet *pkt)
2627 unsigned long value;
2628 if (pkt->length - pkt->savedpos < 4)
2629 return 0; /* arrgh, no way to decline (FIXME?) */
2630 value = GET_32BIT(pkt->body + pkt->savedpos);
2634 static int ssh2_pkt_getbool(struct Packet *pkt)
2636 unsigned long value;
2637 if (pkt->length - pkt->savedpos < 1)
2638 return 0; /* arrgh, no way to decline (FIXME?) */
2639 value = pkt->body[pkt->savedpos] != 0;
2643 static void ssh_pkt_getstring(struct Packet *pkt, char **p, int *length)
2648 if (pkt->length - pkt->savedpos < 4)
2650 len = toint(GET_32BIT(pkt->body + pkt->savedpos));
2655 if (pkt->length - pkt->savedpos < *length)
2657 *p = (char *)(pkt->body + pkt->savedpos);
2658 pkt->savedpos += *length;
2660 static void *ssh_pkt_getdata(struct Packet *pkt, int length)
2662 if (pkt->length - pkt->savedpos < length)
2664 pkt->savedpos += length;
2665 return pkt->body + (pkt->savedpos - length);
2667 static int ssh1_pkt_getrsakey(struct Packet *pkt, struct RSAKey *key,
2668 const unsigned char **keystr)
2672 j = makekey(pkt->body + pkt->savedpos,
2673 pkt->length - pkt->savedpos,
2680 assert(pkt->savedpos < pkt->length);
2684 static Bignum ssh1_pkt_getmp(struct Packet *pkt)
2689 j = ssh1_read_bignum(pkt->body + pkt->savedpos,
2690 pkt->length - pkt->savedpos, &b);
2698 static Bignum ssh2_pkt_getmp(struct Packet *pkt)
2704 ssh_pkt_getstring(pkt, &p, &length);
2709 b = bignum_from_bytes((unsigned char *)p, length);
2714 * Helper function to add an SSH-2 signature blob to a packet.
2715 * Expects to be shown the public key blob as well as the signature
2716 * blob. Normally works just like ssh2_pkt_addstring, but will
2717 * fiddle with the signature packet if necessary for
2718 * BUG_SSH2_RSA_PADDING.
2720 static void ssh2_add_sigblob(Ssh ssh, struct Packet *pkt,
2721 void *pkblob_v, int pkblob_len,
2722 void *sigblob_v, int sigblob_len)
2724 unsigned char *pkblob = (unsigned char *)pkblob_v;
2725 unsigned char *sigblob = (unsigned char *)sigblob_v;
2727 /* dmemdump(pkblob, pkblob_len); */
2728 /* dmemdump(sigblob, sigblob_len); */
2731 * See if this is in fact an ssh-rsa signature and a buggy
2732 * server; otherwise we can just do this the easy way.
2734 if ((ssh->remote_bugs & BUG_SSH2_RSA_PADDING) && pkblob_len > 4+7+4 &&
2735 (GET_32BIT(pkblob) == 7 && !memcmp(pkblob+4, "ssh-rsa", 7))) {
2736 int pos, len, siglen;
2739 * Find the byte length of the modulus.
2742 pos = 4+7; /* skip over "ssh-rsa" */
2743 len = toint(GET_32BIT(pkblob+pos)); /* get length of exponent */
2744 if (len < 0 || len > pkblob_len - pos - 4)
2746 pos += 4 + len; /* skip over exponent */
2747 if (pkblob_len - pos < 4)
2749 len = toint(GET_32BIT(pkblob+pos)); /* find length of modulus */
2750 if (len < 0 || len > pkblob_len - pos - 4)
2752 pos += 4; /* find modulus itself */
2753 while (len > 0 && pkblob[pos] == 0)
2755 /* debug(("modulus length is %d\n", len)); */
2758 * Now find the signature integer.
2760 pos = 4+7; /* skip over "ssh-rsa" */
2761 if (sigblob_len < pos+4)
2763 siglen = toint(GET_32BIT(sigblob+pos));
2764 if (siglen != sigblob_len - pos - 4)
2766 /* debug(("signature length is %d\n", siglen)); */
2768 if (len != siglen) {
2769 unsigned char newlen[4];
2770 ssh2_pkt_addstring_start(pkt);
2771 ssh2_pkt_addstring_data(pkt, (char *)sigblob, pos);
2772 /* dmemdump(sigblob, pos); */
2773 pos += 4; /* point to start of actual sig */
2774 PUT_32BIT(newlen, len);
2775 ssh2_pkt_addstring_data(pkt, (char *)newlen, 4);
2776 /* dmemdump(newlen, 4); */
2778 while (len-- > siglen) {
2779 ssh2_pkt_addstring_data(pkt, (char *)newlen, 1);
2780 /* dmemdump(newlen, 1); */
2782 ssh2_pkt_addstring_data(pkt, (char *)(sigblob+pos), siglen);
2783 /* dmemdump(sigblob+pos, siglen); */
2787 /* Otherwise fall through and do it the easy way. We also come
2788 * here as a fallback if we discover above that the key blob
2789 * is misformatted in some way. */
2793 ssh2_pkt_addstring_start(pkt);
2794 ssh2_pkt_addstring_data(pkt, (char *)sigblob, sigblob_len);
2798 * Examine the remote side's version string and compare it against
2799 * a list of known buggy implementations.
2801 static void ssh_detect_bugs(Ssh ssh, char *vstring)
2803 char *imp; /* pointer to implementation part */
2805 imp += strcspn(imp, "-");
2807 imp += strcspn(imp, "-");
2810 ssh->remote_bugs = 0;
2813 * General notes on server version strings:
2814 * - Not all servers reporting "Cisco-1.25" have all the bugs listed
2815 * here -- in particular, we've heard of one that's perfectly happy
2816 * with SSH1_MSG_IGNOREs -- but this string never seems to change,
2817 * so we can't distinguish them.
2819 if (conf_get_int(ssh->conf, CONF_sshbug_ignore1) == FORCE_ON ||
2820 (conf_get_int(ssh->conf, CONF_sshbug_ignore1) == AUTO &&
2821 (!strcmp(imp, "1.2.18") || !strcmp(imp, "1.2.19") ||
2822 !strcmp(imp, "1.2.20") || !strcmp(imp, "1.2.21") ||
2823 !strcmp(imp, "1.2.22") || !strcmp(imp, "Cisco-1.25") ||
2824 !strcmp(imp, "OSU_1.4alpha3") || !strcmp(imp, "OSU_1.5alpha4")))) {
2826 * These versions don't support SSH1_MSG_IGNORE, so we have
2827 * to use a different defence against password length
2830 ssh->remote_bugs |= BUG_CHOKES_ON_SSH1_IGNORE;
2831 logevent("We believe remote version has SSH-1 ignore bug");
2834 if (conf_get_int(ssh->conf, CONF_sshbug_plainpw1) == FORCE_ON ||
2835 (conf_get_int(ssh->conf, CONF_sshbug_plainpw1) == AUTO &&
2836 (!strcmp(imp, "Cisco-1.25") || !strcmp(imp, "OSU_1.4alpha3")))) {
2838 * These versions need a plain password sent; they can't
2839 * handle having a null and a random length of data after
2842 ssh->remote_bugs |= BUG_NEEDS_SSH1_PLAIN_PASSWORD;
2843 logevent("We believe remote version needs a plain SSH-1 password");
2846 if (conf_get_int(ssh->conf, CONF_sshbug_rsa1) == FORCE_ON ||
2847 (conf_get_int(ssh->conf, CONF_sshbug_rsa1) == AUTO &&
2848 (!strcmp(imp, "Cisco-1.25")))) {
2850 * These versions apparently have no clue whatever about
2851 * RSA authentication and will panic and die if they see
2852 * an AUTH_RSA message.
2854 ssh->remote_bugs |= BUG_CHOKES_ON_RSA;
2855 logevent("We believe remote version can't handle SSH-1 RSA authentication");
2858 if (conf_get_int(ssh->conf, CONF_sshbug_hmac2) == FORCE_ON ||
2859 (conf_get_int(ssh->conf, CONF_sshbug_hmac2) == AUTO &&
2860 !wc_match("* VShell", imp) &&
2861 (wc_match("2.1.0*", imp) || wc_match("2.0.*", imp) ||
2862 wc_match("2.2.0*", imp) || wc_match("2.3.0*", imp) ||
2863 wc_match("2.1 *", imp)))) {
2865 * These versions have the HMAC bug.
2867 ssh->remote_bugs |= BUG_SSH2_HMAC;
2868 logevent("We believe remote version has SSH-2 HMAC bug");
2871 if (conf_get_int(ssh->conf, CONF_sshbug_derivekey2) == FORCE_ON ||
2872 (conf_get_int(ssh->conf, CONF_sshbug_derivekey2) == AUTO &&
2873 !wc_match("* VShell", imp) &&
2874 (wc_match("2.0.0*", imp) || wc_match("2.0.10*", imp) ))) {
2876 * These versions have the key-derivation bug (failing to
2877 * include the literal shared secret in the hashes that
2878 * generate the keys).
2880 ssh->remote_bugs |= BUG_SSH2_DERIVEKEY;
2881 logevent("We believe remote version has SSH-2 key-derivation bug");
2884 if (conf_get_int(ssh->conf, CONF_sshbug_rsapad2) == FORCE_ON ||
2885 (conf_get_int(ssh->conf, CONF_sshbug_rsapad2) == AUTO &&
2886 (wc_match("OpenSSH_2.[5-9]*", imp) ||
2887 wc_match("OpenSSH_3.[0-2]*", imp) ||
2888 wc_match("mod_sftp/0.[0-8]*", imp) ||
2889 wc_match("mod_sftp/0.9.[0-8]", imp)))) {
2891 * These versions have the SSH-2 RSA padding bug.
2893 ssh->remote_bugs |= BUG_SSH2_RSA_PADDING;
2894 logevent("We believe remote version has SSH-2 RSA padding bug");
2897 if (conf_get_int(ssh->conf, CONF_sshbug_pksessid2) == FORCE_ON ||
2898 (conf_get_int(ssh->conf, CONF_sshbug_pksessid2) == AUTO &&
2899 wc_match("OpenSSH_2.[0-2]*", imp))) {
2901 * These versions have the SSH-2 session-ID bug in
2902 * public-key authentication.
2904 ssh->remote_bugs |= BUG_SSH2_PK_SESSIONID;
2905 logevent("We believe remote version has SSH-2 public-key-session-ID bug");
2908 if (conf_get_int(ssh->conf, CONF_sshbug_rekey2) == FORCE_ON ||
2909 (conf_get_int(ssh->conf, CONF_sshbug_rekey2) == AUTO &&
2910 (wc_match("DigiSSH_2.0", imp) ||
2911 wc_match("OpenSSH_2.[0-4]*", imp) ||
2912 wc_match("OpenSSH_2.5.[0-3]*", imp) ||
2913 wc_match("Sun_SSH_1.0", imp) ||
2914 wc_match("Sun_SSH_1.0.1", imp) ||
2915 /* All versions <= 1.2.6 (they changed their format in 1.2.7) */
2916 wc_match("WeOnlyDo-*", imp)))) {
2918 * These versions have the SSH-2 rekey bug.
2920 ssh->remote_bugs |= BUG_SSH2_REKEY;
2921 logevent("We believe remote version has SSH-2 rekey bug");
2924 if (conf_get_int(ssh->conf, CONF_sshbug_maxpkt2) == FORCE_ON ||
2925 (conf_get_int(ssh->conf, CONF_sshbug_maxpkt2) == AUTO &&
2926 (wc_match("1.36_sshlib GlobalSCAPE", imp) ||
2927 wc_match("1.36 sshlib: GlobalScape", imp)))) {
2929 * This version ignores our makpkt and needs to be throttled.
2931 ssh->remote_bugs |= BUG_SSH2_MAXPKT;
2932 logevent("We believe remote version ignores SSH-2 maximum packet size");
2935 if (conf_get_int(ssh->conf, CONF_sshbug_ignore2) == FORCE_ON) {
2937 * Servers that don't support SSH2_MSG_IGNORE. Currently,
2938 * none detected automatically.
2940 ssh->remote_bugs |= BUG_CHOKES_ON_SSH2_IGNORE;
2941 logevent("We believe remote version has SSH-2 ignore bug");
2944 if (conf_get_int(ssh->conf, CONF_sshbug_oldgex2) == FORCE_ON ||
2945 (conf_get_int(ssh->conf, CONF_sshbug_oldgex2) == AUTO &&
2946 (wc_match("OpenSSH_2.[235]*", imp)))) {
2948 * These versions only support the original (pre-RFC4419)
2949 * SSH-2 GEX request, and disconnect with a protocol error if
2950 * we use the newer version.
2952 ssh->remote_bugs |= BUG_SSH2_OLDGEX;
2953 logevent("We believe remote version has outdated SSH-2 GEX");
2956 if (conf_get_int(ssh->conf, CONF_sshbug_winadj) == FORCE_ON) {
2958 * Servers that don't support our winadj request for one
2959 * reason or another. Currently, none detected automatically.
2961 ssh->remote_bugs |= BUG_CHOKES_ON_WINADJ;
2962 logevent("We believe remote version has winadj bug");
2965 if (conf_get_int(ssh->conf, CONF_sshbug_chanreq) == FORCE_ON ||
2966 (conf_get_int(ssh->conf, CONF_sshbug_chanreq) == AUTO &&
2967 (wc_match("OpenSSH_[2-5].*", imp) ||
2968 wc_match("OpenSSH_6.[0-6]*", imp) ||
2969 wc_match("dropbear_0.[2-4][0-9]*", imp) ||
2970 wc_match("dropbear_0.5[01]*", imp)))) {
2972 * These versions have the SSH-2 channel request bug.
2973 * OpenSSH 6.7 and above do not:
2974 * https://bugzilla.mindrot.org/show_bug.cgi?id=1818
2975 * dropbear_0.52 and above do not:
2976 * https://secure.ucc.asn.au/hg/dropbear/rev/cd02449b709c
2978 ssh->remote_bugs |= BUG_SENDS_LATE_REQUEST_REPLY;
2979 logevent("We believe remote version has SSH-2 channel request bug");
2984 * The `software version' part of an SSH version string is required
2985 * to contain no spaces or minus signs.
2987 static void ssh_fix_verstring(char *str)
2989 /* Eat "<protoversion>-". */
2990 while (*str && *str != '-') str++;
2991 assert(*str == '-'); str++;
2993 /* Convert minus signs and spaces in the remaining string into
2996 if (*str == '-' || *str == ' ')
3003 * Send an appropriate SSH version string.
3005 static void ssh_send_verstring(Ssh ssh, const char *protoname, char *svers)
3009 if (ssh->version == 2) {
3011 * Construct a v2 version string.
3013 verstring = dupprintf("%s2.0-%s\015\012", protoname, sshver);
3016 * Construct a v1 version string.
3018 assert(!strcmp(protoname, "SSH-")); /* no v1 bare connection protocol */
3019 verstring = dupprintf("SSH-%s-%s\012",
3020 (ssh_versioncmp(svers, "1.5") <= 0 ?
3025 ssh_fix_verstring(verstring + strlen(protoname));
3027 /* FUZZING make PuTTY insecure, so make live use difficult. */
3031 if (ssh->version == 2) {
3034 * Record our version string.
3036 len = strcspn(verstring, "\015\012");
3037 ssh->v_c = snewn(len + 1, char);
3038 memcpy(ssh->v_c, verstring, len);
3042 logeventf(ssh, "We claim version: %.*s",
3043 strcspn(verstring, "\015\012"), verstring);
3044 s_write(ssh, verstring, strlen(verstring));
3048 static int do_ssh_init(Ssh ssh, unsigned char c)
3050 static const char protoname[] = "SSH-";
3052 struct do_ssh_init_state {
3061 crState(do_ssh_init_state);
3065 /* Search for a line beginning with the protocol name prefix in
3068 for (s->i = 0; protoname[s->i]; s->i++) {
3069 if ((char)c != protoname[s->i]) goto no;
3079 ssh->session_started = TRUE;
3081 s->vstrsize = sizeof(protoname) + 16;
3082 s->vstring = snewn(s->vstrsize, char);
3083 strcpy(s->vstring, protoname);
3084 s->vslen = strlen(protoname);
3087 if (s->vslen >= s->vstrsize - 1) {
3089 s->vstring = sresize(s->vstring, s->vstrsize, char);
3091 s->vstring[s->vslen++] = c;
3094 s->version[s->i] = '\0';
3096 } else if (s->i < sizeof(s->version) - 1)
3097 s->version[s->i++] = c;
3098 } else if (c == '\012')
3100 crReturn(1); /* get another char */
3103 ssh->agentfwd_enabled = FALSE;
3104 ssh->rdpkt2_state.incoming_sequence = 0;
3106 s->vstring[s->vslen] = 0;
3107 s->vstring[strcspn(s->vstring, "\015\012")] = '\0';/* remove EOL chars */
3108 logeventf(ssh, "Server version: %s", s->vstring);
3109 ssh_detect_bugs(ssh, s->vstring);
3112 * Decide which SSH protocol version to support.
3115 /* Anything strictly below "2.0" means protocol 1 is supported. */
3116 s->proto1 = ssh_versioncmp(s->version, "2.0") < 0;
3117 /* Anything greater or equal to "1.99" means protocol 2 is supported. */
3118 s->proto2 = ssh_versioncmp(s->version, "1.99") >= 0;
3120 if (conf_get_int(ssh->conf, CONF_sshprot) == 0 && !s->proto1) {
3121 bombout(("SSH protocol version 1 required by configuration but "
3122 "not provided by server"));
3125 if (conf_get_int(ssh->conf, CONF_sshprot) == 3 && !s->proto2) {
3126 bombout(("SSH protocol version 2 required by configuration but "
3127 "not provided by server"));
3131 if (s->proto2 && (conf_get_int(ssh->conf, CONF_sshprot) >= 2 || !s->proto1))
3136 logeventf(ssh, "Using SSH protocol version %d", ssh->version);
3138 /* Send the version string, if we haven't already */
3139 if (conf_get_int(ssh->conf, CONF_sshprot) != 3)
3140 ssh_send_verstring(ssh, protoname, s->version);
3142 if (ssh->version == 2) {
3145 * Record their version string.
3147 len = strcspn(s->vstring, "\015\012");
3148 ssh->v_s = snewn(len + 1, char);
3149 memcpy(ssh->v_s, s->vstring, len);
3153 * Initialise SSH-2 protocol.
3155 ssh->protocol = ssh2_protocol;
3156 ssh2_protocol_setup(ssh);
3157 ssh->s_rdpkt = ssh2_rdpkt;
3160 * Initialise SSH-1 protocol.
3162 ssh->protocol = ssh1_protocol;
3163 ssh1_protocol_setup(ssh);
3164 ssh->s_rdpkt = ssh1_rdpkt;
3166 if (ssh->version == 2)
3167 do_ssh2_transport(ssh, NULL, -1, NULL);
3169 update_specials_menu(ssh->frontend);
3170 ssh->state = SSH_STATE_BEFORE_SIZE;
3171 ssh->pinger = pinger_new(ssh->conf, &ssh_backend, ssh);
3178 static int do_ssh_connection_init(Ssh ssh, unsigned char c)
3181 * Ordinary SSH begins with the banner "SSH-x.y-...". This is just
3182 * the ssh-connection part, extracted and given a trivial binary
3183 * packet protocol, so we replace 'SSH-' at the start with a new
3184 * name. In proper SSH style (though of course this part of the
3185 * proper SSH protocol _isn't_ subject to this kind of
3186 * DNS-domain-based extension), we define the new name in our
3189 static const char protoname[] =
3190 "SSHCONNECTION@putty.projects.tartarus.org-";
3192 struct do_ssh_connection_init_state {
3200 crState(do_ssh_connection_init_state);
3204 /* Search for a line beginning with the protocol name prefix in
3207 for (s->i = 0; protoname[s->i]; s->i++) {
3208 if ((char)c != protoname[s->i]) goto no;
3218 s->vstrsize = sizeof(protoname) + 16;
3219 s->vstring = snewn(s->vstrsize, char);
3220 strcpy(s->vstring, protoname);
3221 s->vslen = strlen(protoname);
3224 if (s->vslen >= s->vstrsize - 1) {
3226 s->vstring = sresize(s->vstring, s->vstrsize, char);
3228 s->vstring[s->vslen++] = c;
3231 s->version[s->i] = '\0';
3233 } else if (s->i < sizeof(s->version) - 1)
3234 s->version[s->i++] = c;
3235 } else if (c == '\012')
3237 crReturn(1); /* get another char */
3240 ssh->agentfwd_enabled = FALSE;
3241 ssh->rdpkt2_bare_state.incoming_sequence = 0;
3243 s->vstring[s->vslen] = 0;
3244 s->vstring[strcspn(s->vstring, "\015\012")] = '\0';/* remove EOL chars */
3245 logeventf(ssh, "Server version: %s", s->vstring);
3246 ssh_detect_bugs(ssh, s->vstring);
3249 * Decide which SSH protocol version to support. This is easy in
3250 * bare ssh-connection mode: only 2.0 is legal.
3252 if (ssh_versioncmp(s->version, "2.0") < 0) {
3253 bombout(("Server announces compatibility with SSH-1 in bare ssh-connection protocol"));
3256 if (conf_get_int(ssh->conf, CONF_sshprot) == 0) {
3257 bombout(("Bare ssh-connection protocol cannot be run in SSH-1-only mode"));
3263 logeventf(ssh, "Using bare ssh-connection protocol");
3265 /* Send the version string, if we haven't already */
3266 ssh_send_verstring(ssh, protoname, s->version);
3269 * Initialise bare connection protocol.
3271 ssh->protocol = ssh2_bare_connection_protocol;
3272 ssh2_bare_connection_protocol_setup(ssh);
3273 ssh->s_rdpkt = ssh2_bare_connection_rdpkt;
3275 update_specials_menu(ssh->frontend);
3276 ssh->state = SSH_STATE_BEFORE_SIZE;
3277 ssh->pinger = pinger_new(ssh->conf, &ssh_backend, ssh);
3280 * Get authconn (really just conn) under way.
3282 do_ssh2_authconn(ssh, NULL, 0, NULL);
3289 static void ssh_process_incoming_data(Ssh ssh,
3290 const unsigned char **data, int *datalen)
3292 struct Packet *pktin;
3294 pktin = ssh->s_rdpkt(ssh, data, datalen);
3296 ssh->protocol(ssh, NULL, 0, pktin);
3297 ssh_free_packet(pktin);
3301 static void ssh_queue_incoming_data(Ssh ssh,
3302 const unsigned char **data, int *datalen)
3304 bufchain_add(&ssh->queued_incoming_data, *data, *datalen);
3309 static void ssh_process_queued_incoming_data(Ssh ssh)
3312 const unsigned char *data;
3315 while (!ssh->frozen && bufchain_size(&ssh->queued_incoming_data)) {
3316 bufchain_prefix(&ssh->queued_incoming_data, &vdata, &len);
3320 while (!ssh->frozen && len > 0)
3321 ssh_process_incoming_data(ssh, &data, &len);
3324 bufchain_consume(&ssh->queued_incoming_data, origlen - len);
3328 static void ssh_set_frozen(Ssh ssh, int frozen)
3331 sk_set_frozen(ssh->s, frozen);
3332 ssh->frozen = frozen;
3335 static void ssh_gotdata(Ssh ssh, const unsigned char *data, int datalen)
3337 /* Log raw data, if we're in that mode. */
3339 log_packet(ssh->logctx, PKT_INCOMING, -1, NULL, data, datalen,
3340 0, NULL, NULL, 0, NULL);
3342 crBegin(ssh->ssh_gotdata_crstate);
3345 * To begin with, feed the characters one by one to the
3346 * protocol initialisation / selection function do_ssh_init().
3347 * When that returns 0, we're done with the initial greeting
3348 * exchange and can move on to packet discipline.
3351 int ret; /* need not be kept across crReturn */
3353 crReturnV; /* more data please */
3354 ret = ssh->do_ssh_init(ssh, *data);
3362 * We emerge from that loop when the initial negotiation is
3363 * over and we have selected an s_rdpkt function. Now pass
3364 * everything to s_rdpkt, and then pass the resulting packets
3365 * to the proper protocol handler.
3369 while (bufchain_size(&ssh->queued_incoming_data) > 0 || datalen > 0) {
3371 ssh_queue_incoming_data(ssh, &data, &datalen);
3372 /* This uses up all data and cannot cause anything interesting
3373 * to happen; indeed, for anything to happen at all, we must
3374 * return, so break out. */
3376 } else if (bufchain_size(&ssh->queued_incoming_data) > 0) {
3377 /* This uses up some or all data, and may freeze the
3379 ssh_process_queued_incoming_data(ssh);
3381 /* This uses up some or all data, and may freeze the
3383 ssh_process_incoming_data(ssh, &data, &datalen);
3385 /* FIXME this is probably EBW. */
3386 if (ssh->state == SSH_STATE_CLOSED)
3389 /* We're out of data. Go and get some more. */
3395 static int ssh_do_close(Ssh ssh, int notify_exit)
3398 struct ssh_channel *c;
3400 ssh->state = SSH_STATE_CLOSED;
3401 expire_timer_context(ssh);
3406 notify_remote_exit(ssh->frontend);
3411 * Now we must shut down any port- and X-forwarded channels going
3412 * through this connection.
3414 if (ssh->channels) {
3415 while (NULL != (c = index234(ssh->channels, 0))) {
3418 x11_close(c->u.x11.xconn);
3421 case CHAN_SOCKDATA_DORMANT:
3422 pfd_close(c->u.pfd.pf);
3425 del234(ssh->channels, c); /* moving next one to index 0 */
3426 if (ssh->version == 2)
3427 bufchain_clear(&c->v.v2.outbuffer);
3432 * Go through port-forwardings, and close any associated
3433 * listening sockets.
3435 if (ssh->portfwds) {
3436 struct ssh_portfwd *pf;
3437 while (NULL != (pf = index234(ssh->portfwds, 0))) {
3438 /* Dispose of any listening socket. */
3440 pfl_terminate(pf->local);
3441 del234(ssh->portfwds, pf); /* moving next one to index 0 */
3444 freetree234(ssh->portfwds);
3445 ssh->portfwds = NULL;
3449 * Also stop attempting to connection-share.
3451 if (ssh->connshare) {
3452 sharestate_free(ssh->connshare);
3453 ssh->connshare = NULL;
3459 static void ssh_socket_log(Plug plug, int type, SockAddr addr, int port,
3460 const char *error_msg, int error_code)
3462 Ssh ssh = (Ssh) plug;
3465 * While we're attempting connection sharing, don't loudly log
3466 * everything that happens. Real TCP connections need to be logged
3467 * when we _start_ trying to connect, because it might be ages
3468 * before they respond if something goes wrong; but connection
3469 * sharing is local and quick to respond, and it's sufficient to
3470 * simply wait and see whether it worked afterwards.
3473 if (!ssh->attempting_connshare)
3474 backend_socket_log(ssh->frontend, type, addr, port,
3475 error_msg, error_code, ssh->conf,
3476 ssh->session_started);
3479 void ssh_connshare_log(Ssh ssh, int event, const char *logtext,
3480 const char *ds_err, const char *us_err)
3482 if (event == SHARE_NONE) {
3483 /* In this case, 'logtext' is an error message indicating a
3484 * reason why connection sharing couldn't be set up _at all_.
3485 * Failing that, ds_err and us_err indicate why we couldn't be
3486 * a downstream and an upstream respectively. */
3488 logeventf(ssh, "Could not set up connection sharing: %s", logtext);
3491 logeventf(ssh, "Could not set up connection sharing"
3492 " as downstream: %s", ds_err);
3494 logeventf(ssh, "Could not set up connection sharing"
3495 " as upstream: %s", us_err);
3497 } else if (event == SHARE_DOWNSTREAM) {
3498 /* In this case, 'logtext' is a local endpoint address */
3499 logeventf(ssh, "Using existing shared connection at %s", logtext);
3500 /* Also we should mention this in the console window to avoid
3501 * confusing users as to why this window doesn't behave the
3503 if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
3504 c_write_str(ssh,"Reusing a shared connection to this server.\r\n");
3506 } else if (event == SHARE_UPSTREAM) {
3507 /* In this case, 'logtext' is a local endpoint address too */
3508 logeventf(ssh, "Sharing this connection at %s", logtext);
3512 static int ssh_closing(Plug plug, const char *error_msg, int error_code,
3515 Ssh ssh = (Ssh) plug;
3516 int need_notify = ssh_do_close(ssh, FALSE);
3519 if (!ssh->close_expected)
3520 error_msg = "Server unexpectedly closed network connection";
3522 error_msg = "Server closed network connection";
3525 if (ssh->close_expected && ssh->clean_exit && ssh->exitcode < 0)
3529 notify_remote_exit(ssh->frontend);
3532 logevent(error_msg);
3533 if (!ssh->close_expected || !ssh->clean_exit)
3534 connection_fatal(ssh->frontend, "%s", error_msg);
3538 static int ssh_receive(Plug plug, int urgent, char *data, int len)
3540 Ssh ssh = (Ssh) plug;
3541 ssh_gotdata(ssh, (unsigned char *)data, len);
3542 if (ssh->state == SSH_STATE_CLOSED) {
3543 ssh_do_close(ssh, TRUE);
3549 static void ssh_sent(Plug plug, int bufsize)
3551 Ssh ssh = (Ssh) plug;
3553 * If the send backlog on the SSH socket itself clears, we
3554 * should unthrottle the whole world if it was throttled.
3556 if (bufsize < SSH_MAX_BACKLOG)
3557 ssh_throttle_all(ssh, 0, bufsize);
3560 static void ssh_hostport_setup(const char *host, int port, Conf *conf,
3561 char **savedhost, int *savedport,
3564 char *loghost = conf_get_str(conf, CONF_loghost);
3566 *loghost_ret = loghost;
3572 tmphost = dupstr(loghost);
3573 *savedport = 22; /* default ssh port */
3576 * A colon suffix on the hostname string also lets us affect
3577 * savedport. (Unless there are multiple colons, in which case
3578 * we assume this is an unbracketed IPv6 literal.)
3580 colon = host_strrchr(tmphost, ':');
3581 if (colon && colon == host_strchr(tmphost, ':')) {
3584 *savedport = atoi(colon);
3587 *savedhost = host_strduptrim(tmphost);
3590 *savedhost = host_strduptrim(host);
3592 port = 22; /* default ssh port */
3597 static int ssh_test_for_upstream(const char *host, int port, Conf *conf)
3603 random_ref(); /* platform may need this to determine share socket name */
3604 ssh_hostport_setup(host, port, conf, &savedhost, &savedport, NULL);
3605 ret = ssh_share_test_for_upstream(savedhost, savedport, conf);
3613 * Connect to specified host and port.
3614 * Returns an error message, or NULL on success.
3615 * Also places the canonical host name into `realhost'. It must be
3616 * freed by the caller.
3618 static const char *connect_to_host(Ssh ssh, const char *host, int port,
3619 char **realhost, int nodelay, int keepalive)
3621 static const struct plug_function_table fn_table = {
3632 int addressfamily, sshprot;
3634 ssh_hostport_setup(host, port, ssh->conf,
3635 &ssh->savedhost, &ssh->savedport, &loghost);
3637 ssh->fn = &fn_table; /* make 'ssh' usable as a Plug */
3640 * Try connection-sharing, in case that means we don't open a
3641 * socket after all. ssh_connection_sharing_init will connect to a
3642 * previously established upstream if it can, and failing that,
3643 * establish a listening socket for _us_ to be the upstream. In
3644 * the latter case it will return NULL just as if it had done
3645 * nothing, because here we only need to care if we're a
3646 * downstream and need to do our connection setup differently.
3648 ssh->connshare = NULL;
3649 ssh->attempting_connshare = TRUE; /* affects socket logging behaviour */
3650 ssh->s = ssh_connection_sharing_init(ssh->savedhost, ssh->savedport,
3651 ssh->conf, ssh, &ssh->connshare);
3652 ssh->attempting_connshare = FALSE;
3653 if (ssh->s != NULL) {
3655 * We are a downstream.
3657 ssh->bare_connection = TRUE;
3658 ssh->do_ssh_init = do_ssh_connection_init;
3659 ssh->fullhostname = NULL;
3660 *realhost = dupstr(host); /* best we can do */
3663 * We're not a downstream, so open a normal socket.
3665 ssh->do_ssh_init = do_ssh_init;
3670 addressfamily = conf_get_int(ssh->conf, CONF_addressfamily);
3671 addr = name_lookup(host, port, realhost, ssh->conf, addressfamily,
3672 ssh->frontend, "SSH connection");
3673 if ((err = sk_addr_error(addr)) != NULL) {
3677 ssh->fullhostname = dupstr(*realhost); /* save in case of GSSAPI */
3679 ssh->s = new_connection(addr, *realhost, port,
3680 0, 1, nodelay, keepalive,
3681 (Plug) ssh, ssh->conf);
3682 if ((err = sk_socket_error(ssh->s)) != NULL) {
3684 notify_remote_exit(ssh->frontend);
3690 * If the SSH version number's fixed, set it now, and if it's SSH-2,
3691 * send the version string too.
3693 sshprot = conf_get_int(ssh->conf, CONF_sshprot);
3696 if (sshprot == 3 && !ssh->bare_connection) {
3698 ssh_send_verstring(ssh, "SSH-", NULL);
3702 * loghost, if configured, overrides realhost.
3706 *realhost = dupstr(loghost);
3713 * Throttle or unthrottle the SSH connection.
3715 static void ssh_throttle_conn(Ssh ssh, int adjust)
3717 int old_count = ssh->conn_throttle_count;
3718 ssh->conn_throttle_count += adjust;
3719 assert(ssh->conn_throttle_count >= 0);
3720 if (ssh->conn_throttle_count && !old_count) {
3721 ssh_set_frozen(ssh, 1);
3722 } else if (!ssh->conn_throttle_count && old_count) {
3723 ssh_set_frozen(ssh, 0);
3728 * Throttle or unthrottle _all_ local data streams (for when sends
3729 * on the SSH connection itself back up).
3731 static void ssh_throttle_all(Ssh ssh, int enable, int bufsize)
3734 struct ssh_channel *c;
3736 if (enable == ssh->throttled_all)
3738 ssh->throttled_all = enable;
3739 ssh->overall_bufsize = bufsize;
3742 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
3744 case CHAN_MAINSESSION:
3746 * This is treated separately, outside the switch.
3750 x11_override_throttle(c->u.x11.xconn, enable);
3753 /* Agent channels require no buffer management. */
3756 pfd_override_throttle(c->u.pfd.pf, enable);
3762 static void ssh_agent_callback(void *sshv, void *reply, int replylen)
3764 Ssh ssh = (Ssh) sshv;
3766 ssh->agent_response = reply;
3767 ssh->agent_response_len = replylen;
3769 if (ssh->version == 1)
3770 do_ssh1_login(ssh, NULL, -1, NULL);
3772 do_ssh2_authconn(ssh, NULL, -1, NULL);
3775 static void ssh_dialog_callback(void *sshv, int ret)
3777 Ssh ssh = (Ssh) sshv;
3779 ssh->user_response = ret;
3781 if (ssh->version == 1)
3782 do_ssh1_login(ssh, NULL, -1, NULL);
3784 do_ssh2_transport(ssh, NULL, -1, NULL);
3787 * This may have unfrozen the SSH connection, so do a
3790 ssh_process_queued_incoming_data(ssh);
3793 static void ssh_agentf_callback(void *cv, void *reply, int replylen)
3795 struct ssh_channel *c = (struct ssh_channel *)cv;
3797 const void *sentreply = reply;
3799 c->u.a.outstanding_requests--;
3801 /* Fake SSH_AGENT_FAILURE. */
3802 sentreply = "\0\0\0\1\5";
3805 if (ssh->version == 2) {
3806 ssh2_add_channel_data(c, sentreply, replylen);
3809 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
3810 PKT_INT, c->remoteid,
3812 PKT_DATA, sentreply, replylen,
3818 * If we've already seen an incoming EOF but haven't sent an
3819 * outgoing one, this may be the moment to send it.
3821 if (c->u.a.outstanding_requests == 0 && (c->closes & CLOSES_RCVD_EOF))
3822 sshfwd_write_eof(c);
3826 * Client-initiated disconnection. Send a DISCONNECT if `wire_reason'
3827 * non-NULL, otherwise just close the connection. `client_reason' == NULL
3828 * => log `wire_reason'.
3830 static void ssh_disconnect(Ssh ssh, const char *client_reason,
3831 const char *wire_reason,
3832 int code, int clean_exit)
3836 client_reason = wire_reason;
3838 error = dupprintf("Disconnected: %s", client_reason);
3840 error = dupstr("Disconnected");
3842 if (ssh->version == 1) {
3843 send_packet(ssh, SSH1_MSG_DISCONNECT, PKT_STR, wire_reason,
3845 } else if (ssh->version == 2) {
3846 struct Packet *pktout = ssh2_pkt_init(SSH2_MSG_DISCONNECT);
3847 ssh2_pkt_adduint32(pktout, code);
3848 ssh2_pkt_addstring(pktout, wire_reason);
3849 ssh2_pkt_addstring(pktout, "en"); /* language tag */
3850 ssh2_pkt_send_noqueue(ssh, pktout);
3853 ssh->close_expected = TRUE;
3854 ssh->clean_exit = clean_exit;
3855 ssh_closing((Plug)ssh, error, 0, 0);
3859 int verify_ssh_manual_host_key(Ssh ssh, const char *fingerprint,
3860 const struct ssh_signkey *ssh2keytype,
3863 if (!conf_get_str_nthstrkey(ssh->conf, CONF_ssh_manual_hostkeys, 0)) {
3864 return -1; /* no manual keys configured */
3869 * The fingerprint string we've been given will have things
3870 * like 'ssh-rsa 2048' at the front of it. Strip those off and
3871 * narrow down to just the colon-separated hex block at the
3872 * end of the string.
3874 const char *p = strrchr(fingerprint, ' ');
3875 fingerprint = p ? p+1 : fingerprint;
3876 /* Quick sanity checks, including making sure it's in lowercase */
3877 assert(strlen(fingerprint) == 16*3 - 1);
3878 assert(fingerprint[2] == ':');
3879 assert(fingerprint[strspn(fingerprint, "0123456789abcdef:")] == 0);
3881 if (conf_get_str_str_opt(ssh->conf, CONF_ssh_manual_hostkeys,
3883 return 1; /* success */
3888 * Construct the base64-encoded public key blob and see if
3891 unsigned char *binblob;
3893 int binlen, atoms, i;
3894 binblob = ssh2keytype->public_blob(ssh2keydata, &binlen);
3895 atoms = (binlen + 2) / 3;
3896 base64blob = snewn(atoms * 4 + 1, char);
3897 for (i = 0; i < atoms; i++)
3898 base64_encode_atom(binblob + 3*i, binlen - 3*i, base64blob + 4*i);
3899 base64blob[atoms * 4] = '\0';
3901 if (conf_get_str_str_opt(ssh->conf, CONF_ssh_manual_hostkeys,
3904 return 1; /* success */
3913 * Handle the key exchange and user authentication phases.
3915 static int do_ssh1_login(Ssh ssh, const unsigned char *in, int inlen,
3916 struct Packet *pktin)
3919 unsigned char cookie[8], *ptr;
3920 struct MD5Context md5c;
3921 struct do_ssh1_login_state {
3924 unsigned char *rsabuf;
3925 const unsigned char *keystr1, *keystr2;
3926 unsigned long supported_ciphers_mask, supported_auths_mask;
3927 int tried_publickey, tried_agent;
3928 int tis_auth_refused, ccard_auth_refused;
3929 unsigned char session_id[16];
3931 void *publickey_blob;
3932 int publickey_bloblen;
3933 char *publickey_comment;
3934 int privatekey_available, privatekey_encrypted;
3935 prompts_t *cur_prompt;
3938 unsigned char request[5], *response, *p;
3948 struct RSAKey servkey, hostkey;
3950 crState(do_ssh1_login_state);
3957 if (pktin->type != SSH1_SMSG_PUBLIC_KEY) {
3958 bombout(("Public key packet not received"));
3962 logevent("Received public keys");
3964 ptr = ssh_pkt_getdata(pktin, 8);
3966 bombout(("SSH-1 public key packet stopped before random cookie"));
3969 memcpy(cookie, ptr, 8);
3971 if (!ssh1_pkt_getrsakey(pktin, &s->servkey, &s->keystr1) ||
3972 !ssh1_pkt_getrsakey(pktin, &s->hostkey, &s->keystr2)) {
3973 bombout(("Failed to read SSH-1 public keys from public key packet"));
3978 * Log the host key fingerprint.
3982 logevent("Host key fingerprint is:");
3983 strcpy(logmsg, " ");
3984 s->hostkey.comment = NULL;
3985 rsa_fingerprint(logmsg + strlen(logmsg),
3986 sizeof(logmsg) - strlen(logmsg), &s->hostkey);
3990 ssh->v1_remote_protoflags = ssh_pkt_getuint32(pktin);
3991 s->supported_ciphers_mask = ssh_pkt_getuint32(pktin);
3992 s->supported_auths_mask = ssh_pkt_getuint32(pktin);
3993 if ((ssh->remote_bugs & BUG_CHOKES_ON_RSA))
3994 s->supported_auths_mask &= ~(1 << SSH1_AUTH_RSA);
3996 ssh->v1_local_protoflags =
3997 ssh->v1_remote_protoflags & SSH1_PROTOFLAGS_SUPPORTED;
3998 ssh->v1_local_protoflags |= SSH1_PROTOFLAG_SCREEN_NUMBER;
4001 MD5Update(&md5c, s->keystr2, s->hostkey.bytes);
4002 MD5Update(&md5c, s->keystr1, s->servkey.bytes);
4003 MD5Update(&md5c, cookie, 8);
4004 MD5Final(s->session_id, &md5c);
4006 for (i = 0; i < 32; i++)
4007 ssh->session_key[i] = random_byte();
4010 * Verify that the `bits' and `bytes' parameters match.
4012 if (s->hostkey.bits > s->hostkey.bytes * 8 ||
4013 s->servkey.bits > s->servkey.bytes * 8) {
4014 bombout(("SSH-1 public keys were badly formatted"));
4018 s->len = (s->hostkey.bytes > s->servkey.bytes ?
4019 s->hostkey.bytes : s->servkey.bytes);
4021 s->rsabuf = snewn(s->len, unsigned char);
4024 * Verify the host key.
4028 * First format the key into a string.
4030 int len = rsastr_len(&s->hostkey);
4031 char fingerprint[100];
4032 char *keystr = snewn(len, char);
4033 rsastr_fmt(keystr, &s->hostkey);
4034 rsa_fingerprint(fingerprint, sizeof(fingerprint), &s->hostkey);
4036 /* First check against manually configured host keys. */
4037 s->dlgret = verify_ssh_manual_host_key(ssh, fingerprint, NULL, NULL);
4038 if (s->dlgret == 0) { /* did not match */
4039 bombout(("Host key did not appear in manually configured list"));
4042 } else if (s->dlgret < 0) { /* none configured; use standard handling */
4043 ssh_set_frozen(ssh, 1);
4044 s->dlgret = verify_ssh_host_key(ssh->frontend,
4045 ssh->savedhost, ssh->savedport,
4046 "rsa", keystr, fingerprint,
4047 ssh_dialog_callback, ssh);
4052 if (s->dlgret < 0) {
4056 bombout(("Unexpected data from server while waiting"
4057 " for user host key response"));
4060 } while (pktin || inlen > 0);
4061 s->dlgret = ssh->user_response;
4063 ssh_set_frozen(ssh, 0);
4065 if (s->dlgret == 0) {
4066 ssh_disconnect(ssh, "User aborted at host key verification",
4075 for (i = 0; i < 32; i++) {
4076 s->rsabuf[i] = ssh->session_key[i];
4078 s->rsabuf[i] ^= s->session_id[i];
4081 if (s->hostkey.bytes > s->servkey.bytes) {
4082 ret = rsaencrypt(s->rsabuf, 32, &s->servkey);
4084 ret = rsaencrypt(s->rsabuf, s->servkey.bytes, &s->hostkey);
4086 ret = rsaencrypt(s->rsabuf, 32, &s->hostkey);
4088 ret = rsaencrypt(s->rsabuf, s->hostkey.bytes, &s->servkey);
4091 bombout(("SSH-1 public key encryptions failed due to bad formatting"));
4095 logevent("Encrypted session key");
4098 int cipher_chosen = 0, warn = 0;
4099 const char *cipher_string = NULL;
4101 for (i = 0; !cipher_chosen && i < CIPHER_MAX; i++) {
4102 int next_cipher = conf_get_int_int(ssh->conf,
4103 CONF_ssh_cipherlist, i);
4104 if (next_cipher == CIPHER_WARN) {
4105 /* If/when we choose a cipher, warn about it */
4107 } else if (next_cipher == CIPHER_AES) {
4108 /* XXX Probably don't need to mention this. */
4109 logevent("AES not supported in SSH-1, skipping");
4111 switch (next_cipher) {
4112 case CIPHER_3DES: s->cipher_type = SSH_CIPHER_3DES;
4113 cipher_string = "3DES"; break;
4114 case CIPHER_BLOWFISH: s->cipher_type = SSH_CIPHER_BLOWFISH;
4115 cipher_string = "Blowfish"; break;
4116 case CIPHER_DES: s->cipher_type = SSH_CIPHER_DES;
4117 cipher_string = "single-DES"; break;
4119 if (s->supported_ciphers_mask & (1 << s->cipher_type))
4123 if (!cipher_chosen) {
4124 if ((s->supported_ciphers_mask & (1 << SSH_CIPHER_3DES)) == 0)
4125 bombout(("Server violates SSH-1 protocol by not "
4126 "supporting 3DES encryption"));
4128 /* shouldn't happen */
4129 bombout(("No supported ciphers found"));
4133 /* Warn about chosen cipher if necessary. */
4135 ssh_set_frozen(ssh, 1);
4136 s->dlgret = askalg(ssh->frontend, "cipher", cipher_string,
4137 ssh_dialog_callback, ssh);
4138 if (s->dlgret < 0) {
4142 bombout(("Unexpected data from server while waiting"
4143 " for user response"));
4146 } while (pktin || inlen > 0);
4147 s->dlgret = ssh->user_response;
4149 ssh_set_frozen(ssh, 0);
4150 if (s->dlgret == 0) {
4151 ssh_disconnect(ssh, "User aborted at cipher warning", NULL,
4158 switch (s->cipher_type) {
4159 case SSH_CIPHER_3DES:
4160 logevent("Using 3DES encryption");
4162 case SSH_CIPHER_DES:
4163 logevent("Using single-DES encryption");
4165 case SSH_CIPHER_BLOWFISH:
4166 logevent("Using Blowfish encryption");
4170 send_packet(ssh, SSH1_CMSG_SESSION_KEY,
4171 PKT_CHAR, s->cipher_type,
4172 PKT_DATA, cookie, 8,
4173 PKT_CHAR, (s->len * 8) >> 8, PKT_CHAR, (s->len * 8) & 0xFF,
4174 PKT_DATA, s->rsabuf, s->len,
4175 PKT_INT, ssh->v1_local_protoflags, PKT_END);
4177 logevent("Trying to enable encryption...");
4181 ssh->cipher = (s->cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 :
4182 s->cipher_type == SSH_CIPHER_DES ? &ssh_des :
4184 ssh->v1_cipher_ctx = ssh->cipher->make_context();
4185 ssh->cipher->sesskey(ssh->v1_cipher_ctx, ssh->session_key);
4186 logeventf(ssh, "Initialised %s encryption", ssh->cipher->text_name);
4188 ssh->crcda_ctx = crcda_make_context();
4189 logevent("Installing CRC compensation attack detector");
4191 if (s->servkey.modulus) {
4192 sfree(s->servkey.modulus);
4193 s->servkey.modulus = NULL;
4195 if (s->servkey.exponent) {
4196 sfree(s->servkey.exponent);
4197 s->servkey.exponent = NULL;
4199 if (s->hostkey.modulus) {
4200 sfree(s->hostkey.modulus);
4201 s->hostkey.modulus = NULL;
4203 if (s->hostkey.exponent) {
4204 sfree(s->hostkey.exponent);
4205 s->hostkey.exponent = NULL;
4209 if (pktin->type != SSH1_SMSG_SUCCESS) {
4210 bombout(("Encryption not successfully enabled"));
4214 logevent("Successfully started encryption");
4216 fflush(stdout); /* FIXME eh? */
4218 if ((ssh->username = get_remote_username(ssh->conf)) == NULL) {
4219 int ret; /* need not be kept over crReturn */
4220 s->cur_prompt = new_prompts(ssh->frontend);
4221 s->cur_prompt->to_server = TRUE;
4222 s->cur_prompt->name = dupstr("SSH login name");
4223 add_prompt(s->cur_prompt, dupstr("login as: "), TRUE);
4224 ret = get_userpass_input(s->cur_prompt, NULL, 0);
4227 crWaitUntil(!pktin);
4228 ret = get_userpass_input(s->cur_prompt, in, inlen);
4233 * Failed to get a username. Terminate.
4235 free_prompts(s->cur_prompt);
4236 ssh_disconnect(ssh, "No username provided", NULL, 0, TRUE);
4239 ssh->username = dupstr(s->cur_prompt->prompts[0]->result);
4240 free_prompts(s->cur_prompt);
4243 send_packet(ssh, SSH1_CMSG_USER, PKT_STR, ssh->username, PKT_END);
4245 char *userlog = dupprintf("Sent username \"%s\"", ssh->username);
4247 if (flags & FLAG_INTERACTIVE &&
4248 (!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) {
4249 c_write_str(ssh, userlog);
4250 c_write_str(ssh, "\r\n");
4258 if ((s->supported_auths_mask & (1 << SSH1_AUTH_RSA)) == 0) {
4259 /* We must not attempt PK auth. Pretend we've already tried it. */
4260 s->tried_publickey = s->tried_agent = 1;
4262 s->tried_publickey = s->tried_agent = 0;
4264 s->tis_auth_refused = s->ccard_auth_refused = 0;
4266 * Load the public half of any configured keyfile for later use.
4268 s->keyfile = conf_get_filename(ssh->conf, CONF_keyfile);
4269 if (!filename_is_null(s->keyfile)) {
4271 logeventf(ssh, "Reading key file \"%.150s\"",
4272 filename_to_str(s->keyfile));
4273 keytype = key_type(s->keyfile);
4274 if (keytype == SSH_KEYTYPE_SSH1 ||
4275 keytype == SSH_KEYTYPE_SSH1_PUBLIC) {
4277 if (rsakey_pubblob(s->keyfile,
4278 &s->publickey_blob, &s->publickey_bloblen,
4279 &s->publickey_comment, &error)) {
4280 s->privatekey_available = (keytype == SSH_KEYTYPE_SSH1);
4281 if (!s->privatekey_available)
4282 logeventf(ssh, "Key file contains public key only");
4283 s->privatekey_encrypted = rsakey_encrypted(s->keyfile,
4287 logeventf(ssh, "Unable to load key (%s)", error);
4288 msgbuf = dupprintf("Unable to load key file "
4289 "\"%.150s\" (%s)\r\n",
4290 filename_to_str(s->keyfile),
4292 c_write_str(ssh, msgbuf);
4294 s->publickey_blob = NULL;
4298 logeventf(ssh, "Unable to use this key file (%s)",
4299 key_type_to_str(keytype));
4300 msgbuf = dupprintf("Unable to use key file \"%.150s\""
4302 filename_to_str(s->keyfile),
4303 key_type_to_str(keytype));
4304 c_write_str(ssh, msgbuf);
4306 s->publickey_blob = NULL;
4309 s->publickey_blob = NULL;
4311 while (pktin->type == SSH1_SMSG_FAILURE) {
4312 s->pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
4314 if (conf_get_int(ssh->conf, CONF_tryagent) && agent_exists() && !s->tried_agent) {
4316 * Attempt RSA authentication using Pageant.
4322 logevent("Pageant is running. Requesting keys.");
4324 /* Request the keys held by the agent. */
4325 PUT_32BIT(s->request, 1);
4326 s->request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES;
4327 if (!agent_query(s->request, 5, &r, &s->responselen,
4328 ssh_agent_callback, ssh)) {
4332 bombout(("Unexpected data from server while waiting"
4333 " for agent response"));
4336 } while (pktin || inlen > 0);
4337 r = ssh->agent_response;
4338 s->responselen = ssh->agent_response_len;
4340 s->response = (unsigned char *) r;
4341 if (s->response && s->responselen >= 5 &&
4342 s->response[4] == SSH1_AGENT_RSA_IDENTITIES_ANSWER) {
4343 s->p = s->response + 5;
4344 s->nkeys = toint(GET_32BIT(s->p));
4346 logeventf(ssh, "Pageant reported negative key count %d",
4351 logeventf(ssh, "Pageant has %d SSH-1 keys", s->nkeys);
4352 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
4353 unsigned char *pkblob = s->p;
4357 do { /* do while (0) to make breaking easy */
4358 n = ssh1_read_bignum
4359 (s->p, toint(s->responselen-(s->p-s->response)),
4364 n = ssh1_read_bignum
4365 (s->p, toint(s->responselen-(s->p-s->response)),
4370 if (s->responselen - (s->p-s->response) < 4)
4372 s->commentlen = toint(GET_32BIT(s->p));
4374 if (s->commentlen < 0 ||
4375 toint(s->responselen - (s->p-s->response)) <
4378 s->commentp = (char *)s->p;
4379 s->p += s->commentlen;
4383 logevent("Pageant key list packet was truncated");
4387 if (s->publickey_blob) {
4388 if (!memcmp(pkblob, s->publickey_blob,
4389 s->publickey_bloblen)) {
4390 logeventf(ssh, "Pageant key #%d matches "
4391 "configured key file", s->keyi);
4392 s->tried_publickey = 1;
4394 /* Skip non-configured key */
4397 logeventf(ssh, "Trying Pageant key #%d", s->keyi);
4398 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
4399 PKT_BIGNUM, s->key.modulus, PKT_END);
4401 if (pktin->type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
4402 logevent("Key refused");
4405 logevent("Received RSA challenge");
4406 if ((s->challenge = ssh1_pkt_getmp(pktin)) == NULL) {
4407 bombout(("Server's RSA challenge was badly formatted"));
4412 char *agentreq, *q, *ret;
4415 len = 1 + 4; /* message type, bit count */
4416 len += ssh1_bignum_length(s->key.exponent);
4417 len += ssh1_bignum_length(s->key.modulus);
4418 len += ssh1_bignum_length(s->challenge);
4419 len += 16; /* session id */
4420 len += 4; /* response format */
4421 agentreq = snewn(4 + len, char);
4422 PUT_32BIT(agentreq, len);
4424 *q++ = SSH1_AGENTC_RSA_CHALLENGE;
4425 PUT_32BIT(q, bignum_bitcount(s->key.modulus));
4427 q += ssh1_write_bignum(q, s->key.exponent);
4428 q += ssh1_write_bignum(q, s->key.modulus);
4429 q += ssh1_write_bignum(q, s->challenge);
4430 memcpy(q, s->session_id, 16);
4432 PUT_32BIT(q, 1); /* response format */
4433 if (!agent_query(agentreq, len + 4, &vret, &retlen,
4434 ssh_agent_callback, ssh)) {
4439 bombout(("Unexpected data from server"
4440 " while waiting for agent"
4444 } while (pktin || inlen > 0);
4445 vret = ssh->agent_response;
4446 retlen = ssh->agent_response_len;
4451 if (ret[4] == SSH1_AGENT_RSA_RESPONSE) {
4452 logevent("Sending Pageant's response");
4453 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
4454 PKT_DATA, ret + 5, 16,
4458 if (pktin->type == SSH1_SMSG_SUCCESS) {
4460 ("Pageant's response accepted");
4461 if (flags & FLAG_VERBOSE) {
4462 c_write_str(ssh, "Authenticated using"
4464 c_write(ssh, s->commentp,
4466 c_write_str(ssh, "\" from agent\r\n");
4471 ("Pageant's response not accepted");
4474 ("Pageant failed to answer challenge");
4478 logevent("No reply received from Pageant");
4481 freebn(s->key.exponent);
4482 freebn(s->key.modulus);
4483 freebn(s->challenge);
4488 if (s->publickey_blob && !s->tried_publickey)
4489 logevent("Configured key file not in Pageant");
4491 logevent("Failed to get reply from Pageant");
4496 if (s->publickey_blob && s->privatekey_available &&
4497 !s->tried_publickey) {
4499 * Try public key authentication with the specified
4502 int got_passphrase; /* need not be kept over crReturn */
4503 if (flags & FLAG_VERBOSE)
4504 c_write_str(ssh, "Trying public key authentication.\r\n");
4505 s->keyfile = conf_get_filename(ssh->conf, CONF_keyfile);
4506 logeventf(ssh, "Trying public key \"%s\"",
4507 filename_to_str(s->keyfile));
4508 s->tried_publickey = 1;
4509 got_passphrase = FALSE;
4510 while (!got_passphrase) {
4512 * Get a passphrase, if necessary.
4514 char *passphrase = NULL; /* only written after crReturn */
4516 if (!s->privatekey_encrypted) {
4517 if (flags & FLAG_VERBOSE)
4518 c_write_str(ssh, "No passphrase required.\r\n");
4521 int ret; /* need not be kept over crReturn */
4522 s->cur_prompt = new_prompts(ssh->frontend);
4523 s->cur_prompt->to_server = FALSE;
4524 s->cur_prompt->name = dupstr("SSH key passphrase");
4525 add_prompt(s->cur_prompt,
4526 dupprintf("Passphrase for key \"%.100s\": ",
4527 s->publickey_comment), FALSE);
4528 ret = get_userpass_input(s->cur_prompt, NULL, 0);
4531 crWaitUntil(!pktin);
4532 ret = get_userpass_input(s->cur_prompt, in, inlen);
4536 /* Failed to get a passphrase. Terminate. */
4537 free_prompts(s->cur_prompt);
4538 ssh_disconnect(ssh, NULL, "Unable to authenticate",
4542 passphrase = dupstr(s->cur_prompt->prompts[0]->result);
4543 free_prompts(s->cur_prompt);
4546 * Try decrypting key with passphrase.
4548 s->keyfile = conf_get_filename(ssh->conf, CONF_keyfile);
4549 ret = loadrsakey(s->keyfile, &s->key, passphrase,
4552 smemclr(passphrase, strlen(passphrase));
4556 /* Correct passphrase. */
4557 got_passphrase = TRUE;
4558 } else if (ret == 0) {
4559 c_write_str(ssh, "Couldn't load private key from ");
4560 c_write_str(ssh, filename_to_str(s->keyfile));
4561 c_write_str(ssh, " (");
4562 c_write_str(ssh, error);
4563 c_write_str(ssh, ").\r\n");
4564 got_passphrase = FALSE;
4565 break; /* go and try something else */
4566 } else if (ret == -1) {
4567 c_write_str(ssh, "Wrong passphrase.\r\n"); /* FIXME */
4568 got_passphrase = FALSE;
4571 assert(0 && "unexpected return from loadrsakey()");
4572 got_passphrase = FALSE; /* placate optimisers */
4576 if (got_passphrase) {
4579 * Send a public key attempt.
4581 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
4582 PKT_BIGNUM, s->key.modulus, PKT_END);
4585 if (pktin->type == SSH1_SMSG_FAILURE) {
4586 c_write_str(ssh, "Server refused our public key.\r\n");
4587 continue; /* go and try something else */
4589 if (pktin->type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
4590 bombout(("Bizarre response to offer of public key"));
4596 unsigned char buffer[32];
4597 Bignum challenge, response;
4599 if ((challenge = ssh1_pkt_getmp(pktin)) == NULL) {
4600 bombout(("Server's RSA challenge was badly formatted"));
4603 response = rsadecrypt(challenge, &s->key);
4604 freebn(s->key.private_exponent);/* burn the evidence */
4606 for (i = 0; i < 32; i++) {
4607 buffer[i] = bignum_byte(response, 31 - i);
4611 MD5Update(&md5c, buffer, 32);
4612 MD5Update(&md5c, s->session_id, 16);
4613 MD5Final(buffer, &md5c);
4615 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
4616 PKT_DATA, buffer, 16, PKT_END);
4623 if (pktin->type == SSH1_SMSG_FAILURE) {
4624 if (flags & FLAG_VERBOSE)
4625 c_write_str(ssh, "Failed to authenticate with"
4626 " our public key.\r\n");
4627 continue; /* go and try something else */
4628 } else if (pktin->type != SSH1_SMSG_SUCCESS) {
4629 bombout(("Bizarre response to RSA authentication response"));
4633 break; /* we're through! */
4639 * Otherwise, try various forms of password-like authentication.
4641 s->cur_prompt = new_prompts(ssh->frontend);
4643 if (conf_get_int(ssh->conf, CONF_try_tis_auth) &&
4644 (s->supported_auths_mask & (1 << SSH1_AUTH_TIS)) &&
4645 !s->tis_auth_refused) {
4646 s->pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
4647 logevent("Requested TIS authentication");
4648 send_packet(ssh, SSH1_CMSG_AUTH_TIS, PKT_END);
4650 if (pktin->type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
4651 logevent("TIS authentication declined");
4652 if (flags & FLAG_INTERACTIVE)
4653 c_write_str(ssh, "TIS authentication refused.\r\n");
4654 s->tis_auth_refused = 1;
4659 char *instr_suf, *prompt;
4661 ssh_pkt_getstring(pktin, &challenge, &challengelen);
4663 bombout(("TIS challenge packet was badly formed"));
4666 logevent("Received TIS challenge");
4667 s->cur_prompt->to_server = TRUE;
4668 s->cur_prompt->name = dupstr("SSH TIS authentication");
4669 /* Prompt heuristic comes from OpenSSH */
4670 if (memchr(challenge, '\n', challengelen)) {
4671 instr_suf = dupstr("");
4672 prompt = dupprintf("%.*s", challengelen, challenge);
4674 instr_suf = dupprintf("%.*s", challengelen, challenge);
4675 prompt = dupstr("Response: ");
4677 s->cur_prompt->instruction =
4678 dupprintf("Using TIS authentication.%s%s",
4679 (*instr_suf) ? "\n" : "",
4681 s->cur_prompt->instr_reqd = TRUE;
4682 add_prompt(s->cur_prompt, prompt, FALSE);
4686 if (conf_get_int(ssh->conf, CONF_try_tis_auth) &&
4687 (s->supported_auths_mask & (1 << SSH1_AUTH_CCARD)) &&
4688 !s->ccard_auth_refused) {
4689 s->pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE;
4690 logevent("Requested CryptoCard authentication");
4691 send_packet(ssh, SSH1_CMSG_AUTH_CCARD, PKT_END);
4693 if (pktin->type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
4694 logevent("CryptoCard authentication declined");
4695 c_write_str(ssh, "CryptoCard authentication refused.\r\n");
4696 s->ccard_auth_refused = 1;
4701 char *instr_suf, *prompt;
4703 ssh_pkt_getstring(pktin, &challenge, &challengelen);
4705 bombout(("CryptoCard challenge packet was badly formed"));
4708 logevent("Received CryptoCard challenge");
4709 s->cur_prompt->to_server = TRUE;
4710 s->cur_prompt->name = dupstr("SSH CryptoCard authentication");
4711 s->cur_prompt->name_reqd = FALSE;
4712 /* Prompt heuristic comes from OpenSSH */
4713 if (memchr(challenge, '\n', challengelen)) {
4714 instr_suf = dupstr("");
4715 prompt = dupprintf("%.*s", challengelen, challenge);
4717 instr_suf = dupprintf("%.*s", challengelen, challenge);
4718 prompt = dupstr("Response: ");
4720 s->cur_prompt->instruction =
4721 dupprintf("Using CryptoCard authentication.%s%s",
4722 (*instr_suf) ? "\n" : "",
4724 s->cur_prompt->instr_reqd = TRUE;
4725 add_prompt(s->cur_prompt, prompt, FALSE);
4729 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
4730 if ((s->supported_auths_mask & (1 << SSH1_AUTH_PASSWORD)) == 0) {
4731 bombout(("No supported authentication methods available"));
4734 s->cur_prompt->to_server = TRUE;
4735 s->cur_prompt->name = dupstr("SSH password");
4736 add_prompt(s->cur_prompt, dupprintf("%s@%s's password: ",
4737 ssh->username, ssh->savedhost),
4742 * Show password prompt, having first obtained it via a TIS
4743 * or CryptoCard exchange if we're doing TIS or CryptoCard
4747 int ret; /* need not be kept over crReturn */
4748 ret = get_userpass_input(s->cur_prompt, NULL, 0);
4751 crWaitUntil(!pktin);
4752 ret = get_userpass_input(s->cur_prompt, in, inlen);
4757 * Failed to get a password (for example
4758 * because one was supplied on the command line
4759 * which has already failed to work). Terminate.
4761 free_prompts(s->cur_prompt);
4762 ssh_disconnect(ssh, NULL, "Unable to authenticate", 0, TRUE);
4767 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
4769 * Defence against traffic analysis: we send a
4770 * whole bunch of packets containing strings of
4771 * different lengths. One of these strings is the
4772 * password, in a SSH1_CMSG_AUTH_PASSWORD packet.
4773 * The others are all random data in
4774 * SSH1_MSG_IGNORE packets. This way a passive
4775 * listener can't tell which is the password, and
4776 * hence can't deduce the password length.
4778 * Anybody with a password length greater than 16
4779 * bytes is going to have enough entropy in their
4780 * password that a listener won't find it _that_
4781 * much help to know how long it is. So what we'll
4784 * - if password length < 16, we send 15 packets
4785 * containing string lengths 1 through 15
4787 * - otherwise, we let N be the nearest multiple
4788 * of 8 below the password length, and send 8
4789 * packets containing string lengths N through
4790 * N+7. This won't obscure the order of
4791 * magnitude of the password length, but it will
4792 * introduce a bit of extra uncertainty.
4794 * A few servers can't deal with SSH1_MSG_IGNORE, at
4795 * least in this context. For these servers, we need
4796 * an alternative defence. We make use of the fact
4797 * that the password is interpreted as a C string:
4798 * so we can append a NUL, then some random data.
4800 * A few servers can deal with neither SSH1_MSG_IGNORE
4801 * here _nor_ a padded password string.
4802 * For these servers we are left with no defences
4803 * against password length sniffing.
4805 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE) &&
4806 !(ssh->remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) {
4808 * The server can deal with SSH1_MSG_IGNORE, so
4809 * we can use the primary defence.
4811 int bottom, top, pwlen, i;
4814 pwlen = strlen(s->cur_prompt->prompts[0]->result);
4816 bottom = 0; /* zero length passwords are OK! :-) */
4819 bottom = pwlen & ~7;
4823 assert(pwlen >= bottom && pwlen <= top);
4825 randomstr = snewn(top + 1, char);
4827 for (i = bottom; i <= top; i++) {
4829 defer_packet(ssh, s->pwpkt_type,
4830 PKT_STR,s->cur_prompt->prompts[0]->result,
4833 for (j = 0; j < i; j++) {
4835 randomstr[j] = random_byte();
4836 } while (randomstr[j] == '\0');
4838 randomstr[i] = '\0';
4839 defer_packet(ssh, SSH1_MSG_IGNORE,
4840 PKT_STR, randomstr, PKT_END);
4843 logevent("Sending password with camouflage packets");
4844 ssh_pkt_defersend(ssh);
4847 else if (!(ssh->remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) {
4849 * The server can't deal with SSH1_MSG_IGNORE
4850 * but can deal with padded passwords, so we
4851 * can use the secondary defence.
4857 len = strlen(s->cur_prompt->prompts[0]->result);
4858 if (len < sizeof(string)) {
4860 strcpy(string, s->cur_prompt->prompts[0]->result);
4861 len++; /* cover the zero byte */
4862 while (len < sizeof(string)) {
4863 string[len++] = (char) random_byte();
4866 ss = s->cur_prompt->prompts[0]->result;
4868 logevent("Sending length-padded password");
4869 send_packet(ssh, s->pwpkt_type,
4870 PKT_INT, len, PKT_DATA, ss, len,
4874 * The server is believed unable to cope with
4875 * any of our password camouflage methods.
4878 len = strlen(s->cur_prompt->prompts[0]->result);
4879 logevent("Sending unpadded password");
4880 send_packet(ssh, s->pwpkt_type,
4882 PKT_DATA, s->cur_prompt->prompts[0]->result, len,
4886 send_packet(ssh, s->pwpkt_type,
4887 PKT_STR, s->cur_prompt->prompts[0]->result,
4890 logevent("Sent password");
4891 free_prompts(s->cur_prompt);
4893 if (pktin->type == SSH1_SMSG_FAILURE) {
4894 if (flags & FLAG_VERBOSE)
4895 c_write_str(ssh, "Access denied\r\n");
4896 logevent("Authentication refused");
4897 } else if (pktin->type != SSH1_SMSG_SUCCESS) {
4898 bombout(("Strange packet received, type %d", pktin->type));
4904 if (s->publickey_blob) {
4905 sfree(s->publickey_blob);
4906 sfree(s->publickey_comment);
4909 logevent("Authentication successful");
4914 static void ssh_channel_try_eof(struct ssh_channel *c)
4917 assert(c->pending_eof); /* precondition for calling us */
4919 return; /* can't close: not even opened yet */
4920 if (ssh->version == 2 && bufchain_size(&c->v.v2.outbuffer) > 0)
4921 return; /* can't send EOF: pending outgoing data */
4923 c->pending_eof = FALSE; /* we're about to send it */
4924 if (ssh->version == 1) {
4925 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid,
4927 c->closes |= CLOSES_SENT_EOF;
4929 struct Packet *pktout;
4930 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_EOF);
4931 ssh2_pkt_adduint32(pktout, c->remoteid);
4932 ssh2_pkt_send(ssh, pktout);
4933 c->closes |= CLOSES_SENT_EOF;
4934 ssh2_channel_check_close(c);
4938 Conf *sshfwd_get_conf(struct ssh_channel *c)
4944 void sshfwd_write_eof(struct ssh_channel *c)
4948 if (ssh->state == SSH_STATE_CLOSED)
4951 if (c->closes & CLOSES_SENT_EOF)
4954 c->pending_eof = TRUE;
4955 ssh_channel_try_eof(c);
4958 void sshfwd_unclean_close(struct ssh_channel *c, const char *err)
4962 if (ssh->state == SSH_STATE_CLOSED)
4967 x11_close(c->u.x11.xconn);
4968 logeventf(ssh, "Forwarded X11 connection terminated due to local "
4972 case CHAN_SOCKDATA_DORMANT:
4973 pfd_close(c->u.pfd.pf);
4974 logeventf(ssh, "Forwarded port closed due to local error: %s", err);
4977 c->type = CHAN_ZOMBIE;
4978 c->pending_eof = FALSE; /* this will confuse a zombie channel */
4980 ssh2_channel_check_close(c);
4983 int sshfwd_write(struct ssh_channel *c, char *buf, int len)
4987 if (ssh->state == SSH_STATE_CLOSED)
4990 if (ssh->version == 1) {
4991 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
4992 PKT_INT, c->remoteid,
4993 PKT_INT, len, PKT_DATA, buf, len,
4996 * In SSH-1 we can return 0 here - implying that forwarded
4997 * connections are never individually throttled - because
4998 * the only circumstance that can cause throttling will be
4999 * the whole SSH connection backing up, in which case
5000 * _everything_ will be throttled as a whole.
5004 ssh2_add_channel_data(c, buf, len);
5005 return ssh2_try_send(c);
5009 void sshfwd_unthrottle(struct ssh_channel *c, int bufsize)
5014 if (ssh->state == SSH_STATE_CLOSED)
5017 if (ssh->version == 1) {
5018 buflimit = SSH1_BUFFER_LIMIT;
5020 buflimit = c->v.v2.locmaxwin;
5021 ssh2_set_window(c, bufsize < buflimit ? buflimit - bufsize : 0);
5023 if (c->throttling_conn && bufsize <= buflimit) {
5024 c->throttling_conn = 0;
5025 ssh_throttle_conn(ssh, -1);
5029 static void ssh_queueing_handler(Ssh ssh, struct Packet *pktin)
5031 struct queued_handler *qh = ssh->qhead;
5035 assert(pktin->type == qh->msg1 || pktin->type == qh->msg2);
5038 assert(ssh->packet_dispatch[qh->msg1] == ssh_queueing_handler);
5039 ssh->packet_dispatch[qh->msg1] = ssh->q_saved_handler1;
5042 assert(ssh->packet_dispatch[qh->msg2] == ssh_queueing_handler);
5043 ssh->packet_dispatch[qh->msg2] = ssh->q_saved_handler2;
5047 ssh->qhead = qh->next;
5049 if (ssh->qhead->msg1 > 0) {
5050 ssh->q_saved_handler1 = ssh->packet_dispatch[ssh->qhead->msg1];
5051 ssh->packet_dispatch[ssh->qhead->msg1] = ssh_queueing_handler;
5053 if (ssh->qhead->msg2 > 0) {
5054 ssh->q_saved_handler2 = ssh->packet_dispatch[ssh->qhead->msg2];
5055 ssh->packet_dispatch[ssh->qhead->msg2] = ssh_queueing_handler;
5058 ssh->qhead = ssh->qtail = NULL;
5061 qh->handler(ssh, pktin, qh->ctx);
5066 static void ssh_queue_handler(Ssh ssh, int msg1, int msg2,
5067 chandler_fn_t handler, void *ctx)
5069 struct queued_handler *qh;
5071 qh = snew(struct queued_handler);
5074 qh->handler = handler;
5078 if (ssh->qtail == NULL) {
5082 ssh->q_saved_handler1 = ssh->packet_dispatch[ssh->qhead->msg1];
5083 ssh->packet_dispatch[qh->msg1] = ssh_queueing_handler;
5086 ssh->q_saved_handler2 = ssh->packet_dispatch[ssh->qhead->msg2];
5087 ssh->packet_dispatch[qh->msg2] = ssh_queueing_handler;
5090 ssh->qtail->next = qh;
5095 static void ssh_rportfwd_succfail(Ssh ssh, struct Packet *pktin, void *ctx)
5097 struct ssh_rportfwd *rpf, *pf = (struct ssh_rportfwd *)ctx;
5099 if (pktin->type == (ssh->version == 1 ? SSH1_SMSG_SUCCESS :
5100 SSH2_MSG_REQUEST_SUCCESS)) {
5101 logeventf(ssh, "Remote port forwarding from %s enabled",
5104 logeventf(ssh, "Remote port forwarding from %s refused",
5107 rpf = del234(ssh->rportfwds, pf);
5109 pf->pfrec->remote = NULL;
5114 int ssh_alloc_sharing_rportfwd(Ssh ssh, const char *shost, int sport,
5117 struct ssh_rportfwd *pf = snew(struct ssh_rportfwd);
5120 pf->share_ctx = share_ctx;
5121 pf->shost = dupstr(shost);
5123 pf->sportdesc = NULL;
5124 if (!ssh->rportfwds) {
5125 assert(ssh->version == 2);
5126 ssh->rportfwds = newtree234(ssh_rportcmp_ssh2);
5128 if (add234(ssh->rportfwds, pf) != pf) {
5136 static void ssh_sharing_global_request_response(Ssh ssh, struct Packet *pktin,
5139 share_got_pkt_from_server(ctx, pktin->type,
5140 pktin->body, pktin->length);
5143 void ssh_sharing_queue_global_request(Ssh ssh, void *share_ctx)
5145 ssh_queue_handler(ssh, SSH2_MSG_REQUEST_SUCCESS, SSH2_MSG_REQUEST_FAILURE,
5146 ssh_sharing_global_request_response, share_ctx);
5149 static void ssh_setup_portfwd(Ssh ssh, Conf *conf)
5151 struct ssh_portfwd *epf;
5155 if (!ssh->portfwds) {
5156 ssh->portfwds = newtree234(ssh_portcmp);
5159 * Go through the existing port forwardings and tag them
5160 * with status==DESTROY. Any that we want to keep will be
5161 * re-enabled (status==KEEP) as we go through the
5162 * configuration and find out which bits are the same as
5165 struct ssh_portfwd *epf;
5167 for (i = 0; (epf = index234(ssh->portfwds, i)) != NULL; i++)
5168 epf->status = DESTROY;
5171 for (val = conf_get_str_strs(conf, CONF_portfwd, NULL, &key);
5173 val = conf_get_str_strs(conf, CONF_portfwd, key, &key)) {
5174 char *kp, *kp2, *vp, *vp2;
5175 char address_family, type;
5176 int sport,dport,sserv,dserv;
5177 char *sports, *dports, *saddr, *host;
5181 address_family = 'A';
5183 if (*kp == 'A' || *kp == '4' || *kp == '6')
5184 address_family = *kp++;
5185 if (*kp == 'L' || *kp == 'R')
5188 if ((kp2 = host_strchr(kp, ':')) != NULL) {
5190 * There's a colon in the middle of the source port
5191 * string, which means that the part before it is
5192 * actually a source address.
5194 char *saddr_tmp = dupprintf("%.*s", (int)(kp2 - kp), kp);
5195 saddr = host_strduptrim(saddr_tmp);
5202 sport = atoi(sports);
5206 sport = net_service_lookup(sports);
5208 logeventf(ssh, "Service lookup failed for source"
5209 " port \"%s\"", sports);
5213 if (type == 'L' && !strcmp(val, "D")) {
5214 /* dynamic forwarding */
5221 /* ordinary forwarding */
5223 vp2 = vp + host_strcspn(vp, ":");
5224 host = dupprintf("%.*s", (int)(vp2 - vp), vp);
5228 dport = atoi(dports);
5232 dport = net_service_lookup(dports);
5234 logeventf(ssh, "Service lookup failed for destination"
5235 " port \"%s\"", dports);
5240 if (sport && dport) {
5241 /* Set up a description of the source port. */
5242 struct ssh_portfwd *pfrec, *epfrec;
5244 pfrec = snew(struct ssh_portfwd);
5246 pfrec->saddr = saddr;
5247 pfrec->sserv = sserv ? dupstr(sports) : NULL;
5248 pfrec->sport = sport;
5249 pfrec->daddr = host;
5250 pfrec->dserv = dserv ? dupstr(dports) : NULL;
5251 pfrec->dport = dport;
5252 pfrec->local = NULL;
5253 pfrec->remote = NULL;
5254 pfrec->addressfamily = (address_family == '4' ? ADDRTYPE_IPV4 :
5255 address_family == '6' ? ADDRTYPE_IPV6 :
5258 epfrec = add234(ssh->portfwds, pfrec);
5259 if (epfrec != pfrec) {
5260 if (epfrec->status == DESTROY) {
5262 * We already have a port forwarding up and running
5263 * with precisely these parameters. Hence, no need
5264 * to do anything; simply re-tag the existing one
5267 epfrec->status = KEEP;
5270 * Anything else indicates that there was a duplicate
5271 * in our input, which we'll silently ignore.
5273 free_portfwd(pfrec);
5275 pfrec->status = CREATE;
5284 * Now go through and destroy any port forwardings which were
5287 for (i = 0; (epf = index234(ssh->portfwds, i)) != NULL; i++)
5288 if (epf->status == DESTROY) {
5291 message = dupprintf("%s port forwarding from %s%s%d",
5292 epf->type == 'L' ? "local" :
5293 epf->type == 'R' ? "remote" : "dynamic",
5294 epf->saddr ? epf->saddr : "",
5295 epf->saddr ? ":" : "",
5298 if (epf->type != 'D') {
5299 char *msg2 = dupprintf("%s to %s:%d", message,
5300 epf->daddr, epf->dport);
5305 logeventf(ssh, "Cancelling %s", message);
5308 /* epf->remote or epf->local may be NULL if setting up a
5309 * forwarding failed. */
5311 struct ssh_rportfwd *rpf = epf->remote;
5312 struct Packet *pktout;
5315 * Cancel the port forwarding at the server
5318 if (ssh->version == 1) {
5320 * We cannot cancel listening ports on the
5321 * server side in SSH-1! There's no message
5322 * to support it. Instead, we simply remove
5323 * the rportfwd record from the local end
5324 * so that any connections the server tries
5325 * to make on it are rejected.
5328 pktout = ssh2_pkt_init(SSH2_MSG_GLOBAL_REQUEST);
5329 ssh2_pkt_addstring(pktout, "cancel-tcpip-forward");
5330 ssh2_pkt_addbool(pktout, 0);/* _don't_ want reply */
5332 ssh2_pkt_addstring(pktout, epf->saddr);
5333 } else if (conf_get_int(conf, CONF_rport_acceptall)) {
5334 /* XXX: rport_acceptall may not represent
5335 * what was used to open the original connection,
5336 * since it's reconfigurable. */
5337 ssh2_pkt_addstring(pktout, "");
5339 ssh2_pkt_addstring(pktout, "localhost");
5341 ssh2_pkt_adduint32(pktout, epf->sport);
5342 ssh2_pkt_send(ssh, pktout);
5345 del234(ssh->rportfwds, rpf);
5347 } else if (epf->local) {
5348 pfl_terminate(epf->local);
5351 delpos234(ssh->portfwds, i);
5353 i--; /* so we don't skip one in the list */
5357 * And finally, set up any new port forwardings (status==CREATE).
5359 for (i = 0; (epf = index234(ssh->portfwds, i)) != NULL; i++)
5360 if (epf->status == CREATE) {
5361 char *sportdesc, *dportdesc;
5362 sportdesc = dupprintf("%s%s%s%s%d%s",
5363 epf->saddr ? epf->saddr : "",
5364 epf->saddr ? ":" : "",
5365 epf->sserv ? epf->sserv : "",
5366 epf->sserv ? "(" : "",
5368 epf->sserv ? ")" : "");
5369 if (epf->type == 'D') {
5372 dportdesc = dupprintf("%s:%s%s%d%s",
5374 epf->dserv ? epf->dserv : "",
5375 epf->dserv ? "(" : "",
5377 epf->dserv ? ")" : "");
5380 if (epf->type == 'L') {
5381 char *err = pfl_listen(epf->daddr, epf->dport,
5382 epf->saddr, epf->sport,
5383 ssh, conf, &epf->local,
5384 epf->addressfamily);
5386 logeventf(ssh, "Local %sport %s forwarding to %s%s%s",
5387 epf->addressfamily == ADDRTYPE_IPV4 ? "IPv4 " :
5388 epf->addressfamily == ADDRTYPE_IPV6 ? "IPv6 " : "",
5389 sportdesc, dportdesc,
5390 err ? " failed: " : "", err ? err : "");
5393 } else if (epf->type == 'D') {
5394 char *err = pfl_listen(NULL, -1, epf->saddr, epf->sport,
5395 ssh, conf, &epf->local,
5396 epf->addressfamily);
5398 logeventf(ssh, "Local %sport %s SOCKS dynamic forwarding%s%s",
5399 epf->addressfamily == ADDRTYPE_IPV4 ? "IPv4 " :
5400 epf->addressfamily == ADDRTYPE_IPV6 ? "IPv6 " : "",
5402 err ? " failed: " : "", err ? err : "");
5407 struct ssh_rportfwd *pf;
5410 * Ensure the remote port forwardings tree exists.
5412 if (!ssh->rportfwds) {
5413 if (ssh->version == 1)
5414 ssh->rportfwds = newtree234(ssh_rportcmp_ssh1);
5416 ssh->rportfwds = newtree234(ssh_rportcmp_ssh2);
5419 pf = snew(struct ssh_rportfwd);
5420 pf->share_ctx = NULL;
5421 pf->dhost = dupstr(epf->daddr);
5422 pf->dport = epf->dport;
5424 pf->shost = dupstr(epf->saddr);
5425 } else if (conf_get_int(conf, CONF_rport_acceptall)) {
5426 pf->shost = dupstr("");
5428 pf->shost = dupstr("localhost");
5430 pf->sport = epf->sport;
5431 if (add234(ssh->rportfwds, pf) != pf) {
5432 logeventf(ssh, "Duplicate remote port forwarding to %s:%d",
5433 epf->daddr, epf->dport);
5436 logeventf(ssh, "Requesting remote port %s"
5437 " forward to %s", sportdesc, dportdesc);
5439 pf->sportdesc = sportdesc;
5444 if (ssh->version == 1) {
5445 send_packet(ssh, SSH1_CMSG_PORT_FORWARD_REQUEST,
5446 PKT_INT, epf->sport,
5447 PKT_STR, epf->daddr,
5448 PKT_INT, epf->dport,
5450 ssh_queue_handler(ssh, SSH1_SMSG_SUCCESS,
5452 ssh_rportfwd_succfail, pf);
5454 struct Packet *pktout;
5455 pktout = ssh2_pkt_init(SSH2_MSG_GLOBAL_REQUEST);
5456 ssh2_pkt_addstring(pktout, "tcpip-forward");
5457 ssh2_pkt_addbool(pktout, 1);/* want reply */
5458 ssh2_pkt_addstring(pktout, pf->shost);
5459 ssh2_pkt_adduint32(pktout, pf->sport);
5460 ssh2_pkt_send(ssh, pktout);
5462 ssh_queue_handler(ssh, SSH2_MSG_REQUEST_SUCCESS,
5463 SSH2_MSG_REQUEST_FAILURE,
5464 ssh_rportfwd_succfail, pf);
5473 static void ssh1_smsg_stdout_stderr_data(Ssh ssh, struct Packet *pktin)
5476 int stringlen, bufsize;
5478 ssh_pkt_getstring(pktin, &string, &stringlen);
5479 if (string == NULL) {
5480 bombout(("Incoming terminal data packet was badly formed"));
5484 bufsize = from_backend(ssh->frontend, pktin->type == SSH1_SMSG_STDERR_DATA,
5486 if (!ssh->v1_stdout_throttling && bufsize > SSH1_BUFFER_LIMIT) {
5487 ssh->v1_stdout_throttling = 1;
5488 ssh_throttle_conn(ssh, +1);
5492 static void ssh1_smsg_x11_open(Ssh ssh, struct Packet *pktin)
5494 /* Remote side is trying to open a channel to talk to our
5495 * X-Server. Give them back a local channel number. */
5496 struct ssh_channel *c;
5497 int remoteid = ssh_pkt_getuint32(pktin);
5499 logevent("Received X11 connect request");
5500 /* Refuse if X11 forwarding is disabled. */
5501 if (!ssh->X11_fwd_enabled) {
5502 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
5503 PKT_INT, remoteid, PKT_END);
5504 logevent("Rejected X11 connect request");
5506 c = snew(struct ssh_channel);
5509 c->u.x11.xconn = x11_init(ssh->x11authtree, c, NULL, -1);
5510 c->remoteid = remoteid;
5511 c->halfopen = FALSE;
5512 c->localid = alloc_channel_id(ssh);
5514 c->pending_eof = FALSE;
5515 c->throttling_conn = 0;
5516 c->type = CHAN_X11; /* identify channel type */
5517 add234(ssh->channels, c);
5518 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
5519 PKT_INT, c->remoteid, PKT_INT,
5520 c->localid, PKT_END);
5521 logevent("Opened X11 forward channel");
5525 static void ssh1_smsg_agent_open(Ssh ssh, struct Packet *pktin)
5527 /* Remote side is trying to open a channel to talk to our
5528 * agent. Give them back a local channel number. */
5529 struct ssh_channel *c;
5530 int remoteid = ssh_pkt_getuint32(pktin);
5532 /* Refuse if agent forwarding is disabled. */
5533 if (!ssh->agentfwd_enabled) {
5534 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
5535 PKT_INT, remoteid, PKT_END);
5537 c = snew(struct ssh_channel);
5539 c->remoteid = remoteid;
5540 c->halfopen = FALSE;
5541 c->localid = alloc_channel_id(ssh);
5543 c->pending_eof = FALSE;
5544 c->throttling_conn = 0;
5545 c->type = CHAN_AGENT; /* identify channel type */
5546 c->u.a.lensofar = 0;
5547 c->u.a.message = NULL;
5548 c->u.a.outstanding_requests = 0;
5549 add234(ssh->channels, c);
5550 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
5551 PKT_INT, c->remoteid, PKT_INT, c->localid,
5556 static void ssh1_msg_port_open(Ssh ssh, struct Packet *pktin)
5558 /* Remote side is trying to open a channel to talk to a
5559 * forwarded port. Give them back a local channel number. */
5560 struct ssh_rportfwd pf, *pfp;
5566 remoteid = ssh_pkt_getuint32(pktin);
5567 ssh_pkt_getstring(pktin, &host, &hostsize);
5568 port = ssh_pkt_getuint32(pktin);
5570 pf.dhost = dupprintf("%.*s", hostsize, NULLTOEMPTY(host));
5572 pfp = find234(ssh->rportfwds, &pf, NULL);
5575 logeventf(ssh, "Rejected remote port open request for %s:%d",
5577 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
5578 PKT_INT, remoteid, PKT_END);
5580 struct ssh_channel *c = snew(struct ssh_channel);
5583 logeventf(ssh, "Received remote port open request for %s:%d",
5585 err = pfd_connect(&c->u.pfd.pf, pf.dhost, port,
5586 c, ssh->conf, pfp->pfrec->addressfamily);
5588 logeventf(ssh, "Port open failed: %s", err);
5591 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
5592 PKT_INT, remoteid, PKT_END);
5594 c->remoteid = remoteid;
5595 c->halfopen = FALSE;
5596 c->localid = alloc_channel_id(ssh);
5598 c->pending_eof = FALSE;
5599 c->throttling_conn = 0;
5600 c->type = CHAN_SOCKDATA; /* identify channel type */
5601 add234(ssh->channels, c);
5602 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
5603 PKT_INT, c->remoteid, PKT_INT,
5604 c->localid, PKT_END);
5605 logevent("Forwarded port opened successfully");
5612 static void ssh1_msg_channel_open_confirmation(Ssh ssh, struct Packet *pktin)
5614 unsigned int remoteid = ssh_pkt_getuint32(pktin);
5615 unsigned int localid = ssh_pkt_getuint32(pktin);
5616 struct ssh_channel *c;
5618 c = find234(ssh->channels, &remoteid, ssh_channelfind);
5619 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
5620 c->remoteid = localid;
5621 c->halfopen = FALSE;
5622 c->type = CHAN_SOCKDATA;
5623 c->throttling_conn = 0;
5624 pfd_confirm(c->u.pfd.pf);
5627 if (c && c->pending_eof) {
5629 * We have a pending close on this channel,
5630 * which we decided on before the server acked
5631 * the channel open. So now we know the
5632 * remoteid, we can close it again.
5634 ssh_channel_try_eof(c);
5638 static void ssh1_msg_channel_open_failure(Ssh ssh, struct Packet *pktin)
5640 unsigned int remoteid = ssh_pkt_getuint32(pktin);
5641 struct ssh_channel *c;
5643 c = find234(ssh->channels, &remoteid, ssh_channelfind);
5644 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
5645 logevent("Forwarded connection refused by server");
5646 pfd_close(c->u.pfd.pf);
5647 del234(ssh->channels, c);
5652 static void ssh1_msg_channel_close(Ssh ssh, struct Packet *pktin)
5654 /* Remote side closes a channel. */
5655 unsigned i = ssh_pkt_getuint32(pktin);
5656 struct ssh_channel *c;
5657 c = find234(ssh->channels, &i, ssh_channelfind);
5658 if (c && !c->halfopen) {
5660 if (pktin->type == SSH1_MSG_CHANNEL_CLOSE &&
5661 !(c->closes & CLOSES_RCVD_EOF)) {
5663 * Received CHANNEL_CLOSE, which we translate into
5666 int send_close = FALSE;
5668 c->closes |= CLOSES_RCVD_EOF;
5673 x11_send_eof(c->u.x11.xconn);
5679 pfd_send_eof(c->u.pfd.pf);
5688 if (send_close && !(c->closes & CLOSES_SENT_EOF)) {
5689 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid,
5691 c->closes |= CLOSES_SENT_EOF;
5695 if (pktin->type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION &&
5696 !(c->closes & CLOSES_RCVD_CLOSE)) {
5698 if (!(c->closes & CLOSES_SENT_EOF)) {
5699 bombout(("Received CHANNEL_CLOSE_CONFIRMATION for channel %d"
5700 " for which we never sent CHANNEL_CLOSE\n", i));
5703 c->closes |= CLOSES_RCVD_CLOSE;
5706 if (!((CLOSES_SENT_EOF | CLOSES_RCVD_EOF) & ~c->closes) &&
5707 !(c->closes & CLOSES_SENT_CLOSE)) {
5708 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION,
5709 PKT_INT, c->remoteid, PKT_END);
5710 c->closes |= CLOSES_SENT_CLOSE;
5713 if (!((CLOSES_SENT_CLOSE | CLOSES_RCVD_CLOSE) & ~c->closes))
5714 ssh_channel_destroy(c);
5716 bombout(("Received CHANNEL_CLOSE%s for %s channel %d\n",
5717 pktin->type == SSH1_MSG_CHANNEL_CLOSE ? "" :
5718 "_CONFIRMATION", c ? "half-open" : "nonexistent",
5723 static void ssh1_msg_channel_data(Ssh ssh, struct Packet *pktin)
5725 /* Data sent down one of our channels. */
5726 int i = ssh_pkt_getuint32(pktin);
5729 struct ssh_channel *c;
5731 ssh_pkt_getstring(pktin, &p, &len);
5733 c = find234(ssh->channels, &i, ssh_channelfind);
5738 bufsize = x11_send(c->u.x11.xconn, p, len);
5741 bufsize = pfd_send(c->u.pfd.pf, p, len);
5744 /* Data for an agent message. Buffer it. */
5746 if (c->u.a.lensofar < 4) {
5747 unsigned int l = min(4 - c->u.a.lensofar, (unsigned)len);
5748 memcpy(c->u.a.msglen + c->u.a.lensofar, p,
5752 c->u.a.lensofar += l;
5754 if (c->u.a.lensofar == 4) {
5756 4 + GET_32BIT(c->u.a.msglen);
5757 c->u.a.message = snewn(c->u.a.totallen,
5759 memcpy(c->u.a.message, c->u.a.msglen, 4);
5761 if (c->u.a.lensofar >= 4 && len > 0) {
5763 min(c->u.a.totallen - c->u.a.lensofar,
5765 memcpy(c->u.a.message + c->u.a.lensofar, p,
5769 c->u.a.lensofar += l;
5771 if (c->u.a.lensofar == c->u.a.totallen) {
5774 c->u.a.outstanding_requests++;
5775 if (agent_query(c->u.a.message,
5778 ssh_agentf_callback, c))
5779 ssh_agentf_callback(c, reply, replylen);
5780 sfree(c->u.a.message);
5781 c->u.a.lensofar = 0;
5784 bufsize = 0; /* agent channels never back up */
5787 if (!c->throttling_conn && bufsize > SSH1_BUFFER_LIMIT) {
5788 c->throttling_conn = 1;
5789 ssh_throttle_conn(ssh, +1);
5794 static void ssh1_smsg_exit_status(Ssh ssh, struct Packet *pktin)
5796 ssh->exitcode = ssh_pkt_getuint32(pktin);
5797 logeventf(ssh, "Server sent command exit status %d", ssh->exitcode);
5798 send_packet(ssh, SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
5800 * In case `helpful' firewalls or proxies tack
5801 * extra human-readable text on the end of the
5802 * session which we might mistake for another
5803 * encrypted packet, we close the session once
5804 * we've sent EXIT_CONFIRMATION.
5806 ssh_disconnect(ssh, NULL, NULL, 0, TRUE);
5809 /* Helper function to deal with sending tty modes for REQUEST_PTY */
5810 static void ssh1_send_ttymode(void *data, char *mode, char *val)
5812 struct Packet *pktout = (struct Packet *)data;
5814 unsigned int arg = 0;
5815 while (strcmp(mode, ssh_ttymodes[i].mode) != 0) i++;
5816 if (i == lenof(ssh_ttymodes)) return;
5817 switch (ssh_ttymodes[i].type) {
5819 arg = ssh_tty_parse_specchar(val);
5822 arg = ssh_tty_parse_boolean(val);
5825 ssh2_pkt_addbyte(pktout, ssh_ttymodes[i].opcode);
5826 ssh2_pkt_addbyte(pktout, arg);
5829 int ssh_agent_forwarding_permitted(Ssh ssh)
5831 return conf_get_int(ssh->conf, CONF_agentfwd) && agent_exists();
5834 static void do_ssh1_connection(Ssh ssh, const unsigned char *in, int inlen,
5835 struct Packet *pktin)
5837 crBegin(ssh->do_ssh1_connection_crstate);
5839 ssh->packet_dispatch[SSH1_SMSG_STDOUT_DATA] =
5840 ssh->packet_dispatch[SSH1_SMSG_STDERR_DATA] =
5841 ssh1_smsg_stdout_stderr_data;
5843 ssh->packet_dispatch[SSH1_MSG_CHANNEL_OPEN_CONFIRMATION] =
5844 ssh1_msg_channel_open_confirmation;
5845 ssh->packet_dispatch[SSH1_MSG_CHANNEL_OPEN_FAILURE] =
5846 ssh1_msg_channel_open_failure;
5847 ssh->packet_dispatch[SSH1_MSG_CHANNEL_CLOSE] =
5848 ssh->packet_dispatch[SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION] =
5849 ssh1_msg_channel_close;
5850 ssh->packet_dispatch[SSH1_MSG_CHANNEL_DATA] = ssh1_msg_channel_data;
5851 ssh->packet_dispatch[SSH1_SMSG_EXIT_STATUS] = ssh1_smsg_exit_status;
5853 if (ssh_agent_forwarding_permitted(ssh)) {
5854 logevent("Requesting agent forwarding");
5855 send_packet(ssh, SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END);
5859 if (pktin->type != SSH1_SMSG_SUCCESS
5860 && pktin->type != SSH1_SMSG_FAILURE) {
5861 bombout(("Protocol confusion"));
5863 } else if (pktin->type == SSH1_SMSG_FAILURE) {
5864 logevent("Agent forwarding refused");
5866 logevent("Agent forwarding enabled");
5867 ssh->agentfwd_enabled = TRUE;
5868 ssh->packet_dispatch[SSH1_SMSG_AGENT_OPEN] = ssh1_smsg_agent_open;
5872 if (conf_get_int(ssh->conf, CONF_x11_forward)) {
5874 x11_setup_display(conf_get_str(ssh->conf, CONF_x11_display),
5876 if (!ssh->x11disp) {
5877 /* FIXME: return an error message from x11_setup_display */
5878 logevent("X11 forwarding not enabled: unable to"
5879 " initialise X display");
5881 ssh->x11auth = x11_invent_fake_auth
5882 (ssh->x11authtree, conf_get_int(ssh->conf, CONF_x11_auth));
5883 ssh->x11auth->disp = ssh->x11disp;
5885 logevent("Requesting X11 forwarding");
5886 if (ssh->v1_local_protoflags & SSH1_PROTOFLAG_SCREEN_NUMBER) {
5887 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
5888 PKT_STR, ssh->x11auth->protoname,
5889 PKT_STR, ssh->x11auth->datastring,
5890 PKT_INT, ssh->x11disp->screennum,
5893 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
5894 PKT_STR, ssh->x11auth->protoname,
5895 PKT_STR, ssh->x11auth->datastring,
5901 if (pktin->type != SSH1_SMSG_SUCCESS
5902 && pktin->type != SSH1_SMSG_FAILURE) {
5903 bombout(("Protocol confusion"));
5905 } else if (pktin->type == SSH1_SMSG_FAILURE) {
5906 logevent("X11 forwarding refused");
5908 logevent("X11 forwarding enabled");
5909 ssh->X11_fwd_enabled = TRUE;
5910 ssh->packet_dispatch[SSH1_SMSG_X11_OPEN] = ssh1_smsg_x11_open;
5915 ssh_setup_portfwd(ssh, ssh->conf);
5916 ssh->packet_dispatch[SSH1_MSG_PORT_OPEN] = ssh1_msg_port_open;
5918 if (!conf_get_int(ssh->conf, CONF_nopty)) {
5920 /* Unpick the terminal-speed string. */
5921 /* XXX perhaps we should allow no speeds to be sent. */
5922 ssh->ospeed = 38400; ssh->ispeed = 38400; /* last-resort defaults */
5923 sscanf(conf_get_str(ssh->conf, CONF_termspeed), "%d,%d", &ssh->ospeed, &ssh->ispeed);
5924 /* Send the pty request. */
5925 pkt = ssh1_pkt_init(SSH1_CMSG_REQUEST_PTY);
5926 ssh_pkt_addstring(pkt, conf_get_str(ssh->conf, CONF_termtype));
5927 ssh_pkt_adduint32(pkt, ssh->term_height);
5928 ssh_pkt_adduint32(pkt, ssh->term_width);
5929 ssh_pkt_adduint32(pkt, 0); /* width in pixels */
5930 ssh_pkt_adduint32(pkt, 0); /* height in pixels */
5931 parse_ttymodes(ssh, ssh1_send_ttymode, (void *)pkt);
5932 ssh_pkt_addbyte(pkt, SSH1_TTY_OP_ISPEED);
5933 ssh_pkt_adduint32(pkt, ssh->ispeed);
5934 ssh_pkt_addbyte(pkt, SSH1_TTY_OP_OSPEED);
5935 ssh_pkt_adduint32(pkt, ssh->ospeed);
5936 ssh_pkt_addbyte(pkt, SSH_TTY_OP_END);
5938 ssh->state = SSH_STATE_INTERMED;
5942 if (pktin->type != SSH1_SMSG_SUCCESS
5943 && pktin->type != SSH1_SMSG_FAILURE) {
5944 bombout(("Protocol confusion"));
5946 } else if (pktin->type == SSH1_SMSG_FAILURE) {
5947 c_write_str(ssh, "Server refused to allocate pty\r\n");
5948 ssh->editing = ssh->echoing = 1;
5950 logeventf(ssh, "Allocated pty (ospeed %dbps, ispeed %dbps)",
5951 ssh->ospeed, ssh->ispeed);
5952 ssh->got_pty = TRUE;
5955 ssh->editing = ssh->echoing = 1;
5958 if (conf_get_int(ssh->conf, CONF_compression)) {
5959 send_packet(ssh, SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END);
5963 if (pktin->type != SSH1_SMSG_SUCCESS
5964 && pktin->type != SSH1_SMSG_FAILURE) {
5965 bombout(("Protocol confusion"));
5967 } else if (pktin->type == SSH1_SMSG_FAILURE) {
5968 c_write_str(ssh, "Server refused to compress\r\n");
5970 logevent("Started compression");
5971 ssh->v1_compressing = TRUE;
5972 ssh->cs_comp_ctx = zlib_compress_init();
5973 logevent("Initialised zlib (RFC1950) compression");
5974 ssh->sc_comp_ctx = zlib_decompress_init();
5975 logevent("Initialised zlib (RFC1950) decompression");
5979 * Start the shell or command.
5981 * Special case: if the first-choice command is an SSH-2
5982 * subsystem (hence not usable here) and the second choice
5983 * exists, we fall straight back to that.
5986 char *cmd = conf_get_str(ssh->conf, CONF_remote_cmd);
5988 if (conf_get_int(ssh->conf, CONF_ssh_subsys) &&
5989 conf_get_str(ssh->conf, CONF_remote_cmd2)) {
5990 cmd = conf_get_str(ssh->conf, CONF_remote_cmd2);
5991 ssh->fallback_cmd = TRUE;
5994 send_packet(ssh, SSH1_CMSG_EXEC_CMD, PKT_STR, cmd, PKT_END);
5996 send_packet(ssh, SSH1_CMSG_EXEC_SHELL, PKT_END);
5997 logevent("Started session");
6000 ssh->state = SSH_STATE_SESSION;
6001 if (ssh->size_needed)
6002 ssh_size(ssh, ssh->term_width, ssh->term_height);
6003 if (ssh->eof_needed)
6004 ssh_special(ssh, TS_EOF);
6007 ldisc_echoedit_update(ssh->ldisc); /* cause ldisc to notice changes */
6009 ssh->channels = newtree234(ssh_channelcmp);
6013 * By this point, most incoming packets are already being
6014 * handled by the dispatch table, and we need only pay
6015 * attention to the unusual ones.
6020 if (pktin->type == SSH1_SMSG_SUCCESS) {
6021 /* may be from EXEC_SHELL on some servers */
6022 } else if (pktin->type == SSH1_SMSG_FAILURE) {
6023 /* may be from EXEC_SHELL on some servers
6024 * if no pty is available or in other odd cases. Ignore */
6026 bombout(("Strange packet received: type %d", pktin->type));
6031 int len = min(inlen, 512);
6032 send_packet(ssh, SSH1_CMSG_STDIN_DATA,
6033 PKT_INT, len, PKT_DATA, in, len,
6045 * Handle the top-level SSH-2 protocol.
6047 static void ssh1_msg_debug(Ssh ssh, struct Packet *pktin)
6052 ssh_pkt_getstring(pktin, &msg, &msglen);
6053 logeventf(ssh, "Remote debug message: %.*s", msglen, NULLTOEMPTY(msg));
6056 static void ssh1_msg_disconnect(Ssh ssh, struct Packet *pktin)
6058 /* log reason code in disconnect message */
6062 ssh_pkt_getstring(pktin, &msg, &msglen);
6063 bombout(("Server sent disconnect message:\n\"%.*s\"",
6064 msglen, NULLTOEMPTY(msg)));
6067 static void ssh_msg_ignore(Ssh ssh, struct Packet *pktin)
6069 /* Do nothing, because we're ignoring it! Duhh. */
6072 static void ssh1_protocol_setup(Ssh ssh)
6077 * Most messages are handled by the coroutines.
6079 for (i = 0; i < 256; i++)
6080 ssh->packet_dispatch[i] = NULL;
6083 * These special message types we install handlers for.
6085 ssh->packet_dispatch[SSH1_MSG_DISCONNECT] = ssh1_msg_disconnect;
6086 ssh->packet_dispatch[SSH1_MSG_IGNORE] = ssh_msg_ignore;
6087 ssh->packet_dispatch[SSH1_MSG_DEBUG] = ssh1_msg_debug;
6090 static void ssh1_protocol(Ssh ssh, const void *vin, int inlen,
6091 struct Packet *pktin)
6093 const unsigned char *in = (const unsigned char *)vin;
6094 if (ssh->state == SSH_STATE_CLOSED)
6097 if (pktin && ssh->packet_dispatch[pktin->type]) {
6098 ssh->packet_dispatch[pktin->type](ssh, pktin);
6102 if (!ssh->protocol_initial_phase_done) {
6103 if (do_ssh1_login(ssh, in, inlen, pktin))
6104 ssh->protocol_initial_phase_done = TRUE;
6109 do_ssh1_connection(ssh, in, inlen, pktin);
6113 * Utility routines for decoding comma-separated strings in KEXINIT.
6115 static int first_in_commasep_string(char const *needle, char const *haystack,
6119 if (!needle || !haystack) /* protect against null pointers */
6121 needlen = strlen(needle);
6123 if (haylen >= needlen && /* haystack is long enough */
6124 !memcmp(needle, haystack, needlen) && /* initial match */
6125 (haylen == needlen || haystack[needlen] == ',')
6126 /* either , or EOS follows */
6132 static int in_commasep_string(char const *needle, char const *haystack,
6137 if (!needle || !haystack) /* protect against null pointers */
6140 * Is it at the start of the string?
6142 if (first_in_commasep_string(needle, haystack, haylen))
6145 * If not, search for the next comma and resume after that.
6146 * If no comma found, terminate.
6148 p = memchr(haystack, ',', haylen);
6150 /* + 1 to skip over comma */
6151 return in_commasep_string(needle, p + 1, haylen - (p + 1 - haystack));
6155 * Add a value to the comma-separated string at the end of the packet.
6157 static void ssh2_pkt_addstring_commasep(struct Packet *pkt, const char *data)
6159 if (pkt->length - pkt->savedpos > 0)
6160 ssh_pkt_addstring_str(pkt, ",");
6161 ssh_pkt_addstring_str(pkt, data);
6166 * SSH-2 key derivation (RFC 4253 section 7.2).
6168 static unsigned char *ssh2_mkkey(Ssh ssh, Bignum K, unsigned char *H,
6169 char chr, int keylen)
6171 const struct ssh_hash *h = ssh->kex->hash;
6179 /* Round up to the next multiple of hash length. */
6180 keylen_padded = ((keylen + h->hlen - 1) / h->hlen) * h->hlen;
6182 key = snewn(keylen_padded, unsigned char);
6184 /* First hlen bytes. */
6186 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
6187 hash_mpint(h, s, K);
6188 h->bytes(s, H, h->hlen);
6189 h->bytes(s, &chr, 1);
6190 h->bytes(s, ssh->v2_session_id, ssh->v2_session_id_len);
6193 /* Subsequent blocks of hlen bytes. */
6194 if (keylen_padded > h->hlen) {
6198 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
6199 hash_mpint(h, s, K);
6200 h->bytes(s, H, h->hlen);
6202 for (offset = h->hlen; offset < keylen_padded; offset += h->hlen) {
6203 h->bytes(s, key + offset - h->hlen, h->hlen);
6205 h->final(s2, key + offset);
6211 /* Now clear any extra bytes of key material beyond the length
6212 * we're officially returning, because the caller won't know to
6214 if (keylen_padded > keylen)
6215 smemclr(key + keylen, keylen_padded - keylen);
6221 * Structure for constructing KEXINIT algorithm lists.
6223 #define MAXKEXLIST 16
6224 struct kexinit_algorithm {
6228 const struct ssh_kex *kex;
6231 const struct ssh_signkey *hostkey;
6233 const struct ssh2_cipher *cipher;
6237 const struct ssh_mac *mac;
6240 const struct ssh_compress *comp;
6245 * Find a slot in a KEXINIT algorithm list to use for a new algorithm.
6246 * If the algorithm is already in the list, return a pointer to its
6247 * entry, otherwise return an entry from the end of the list.
6248 * This assumes that every time a particular name is passed in, it
6249 * comes from the same string constant. If this isn't true, this
6250 * function may need to be rewritten to use strcmp() instead.
6252 static struct kexinit_algorithm *ssh2_kexinit_addalg(struct kexinit_algorithm
6253 *list, const char *name)
6257 for (i = 0; i < MAXKEXLIST; i++)
6258 if (list[i].name == NULL || list[i].name == name) {
6259 list[i].name = name;
6262 assert(!"No space in KEXINIT list");
6267 * Handle the SSH-2 transport layer.
6269 static void do_ssh2_transport(Ssh ssh, const void *vin, int inlen,
6270 struct Packet *pktin)
6272 const unsigned char *in = (const unsigned char *)vin;
6274 KEXLIST_KEX, KEXLIST_HOSTKEY, KEXLIST_CSCIPHER, KEXLIST_SCCIPHER,
6275 KEXLIST_CSMAC, KEXLIST_SCMAC, KEXLIST_CSCOMP, KEXLIST_SCCOMP,
6278 const char * kexlist_descr[NKEXLIST] = {
6279 "key exchange algorithm", "host key algorithm",
6280 "client-to-server cipher", "server-to-client cipher",
6281 "client-to-server MAC", "server-to-client MAC",
6282 "client-to-server compression method",
6283 "server-to-client compression method" };
6284 struct do_ssh2_transport_state {
6286 int nbits, pbits, warn_kex, warn_cscipher, warn_sccipher;
6287 Bignum p, g, e, f, K;
6290 int kex_init_value, kex_reply_value;
6291 const struct ssh_mac **maclist;
6293 const struct ssh2_cipher *cscipher_tobe;
6294 const struct ssh2_cipher *sccipher_tobe;
6295 const struct ssh_mac *csmac_tobe;
6296 const struct ssh_mac *scmac_tobe;
6297 int csmac_etm_tobe, scmac_etm_tobe;
6298 const struct ssh_compress *cscomp_tobe;
6299 const struct ssh_compress *sccomp_tobe;
6300 char *hostkeydata, *sigdata, *rsakeydata, *keystr, *fingerprint;
6301 int hostkeylen, siglen, rsakeylen;
6302 void *hkey; /* actual host key */
6303 void *rsakey; /* for RSA kex */
6304 void *eckey; /* for ECDH kex */
6305 unsigned char exchange_hash[SSH2_KEX_MAX_HASH_LEN];
6306 int n_preferred_kex;
6307 const struct ssh_kexes *preferred_kex[KEX_MAX];
6308 int n_preferred_ciphers;
6309 const struct ssh2_ciphers *preferred_ciphers[CIPHER_MAX];
6310 const struct ssh_compress *preferred_comp;
6311 int userauth_succeeded; /* for delayed compression */
6312 int pending_compression;
6313 int got_session_id, activated_authconn;
6314 struct Packet *pktout;
6318 struct kexinit_algorithm kexlists[NKEXLIST][MAXKEXLIST];
6320 crState(do_ssh2_transport_state);
6322 assert(!ssh->bare_connection);
6326 s->cscipher_tobe = s->sccipher_tobe = NULL;
6327 s->csmac_tobe = s->scmac_tobe = NULL;
6328 s->cscomp_tobe = s->sccomp_tobe = NULL;
6330 s->got_session_id = s->activated_authconn = FALSE;
6331 s->userauth_succeeded = FALSE;
6332 s->pending_compression = FALSE;
6335 * Be prepared to work around the buggy MAC problem.
6337 if (ssh->remote_bugs & BUG_SSH2_HMAC)
6338 s->maclist = buggymacs, s->nmacs = lenof(buggymacs);
6340 s->maclist = macs, s->nmacs = lenof(macs);
6343 ssh->pkt_kctx = SSH2_PKTCTX_NOKEX;
6346 struct kexinit_algorithm *alg;
6349 * Set up the preferred key exchange. (NULL => warn below here)
6351 s->n_preferred_kex = 0;
6352 for (i = 0; i < KEX_MAX; i++) {
6353 switch (conf_get_int_int(ssh->conf, CONF_ssh_kexlist, i)) {
6355 s->preferred_kex[s->n_preferred_kex++] =
6356 &ssh_diffiehellman_gex;
6359 s->preferred_kex[s->n_preferred_kex++] =
6360 &ssh_diffiehellman_group14;
6363 s->preferred_kex[s->n_preferred_kex++] =
6364 &ssh_diffiehellman_group1;
6367 s->preferred_kex[s->n_preferred_kex++] =
6371 s->preferred_kex[s->n_preferred_kex++] =
6375 /* Flag for later. Don't bother if it's the last in
6377 if (i < KEX_MAX - 1) {
6378 s->preferred_kex[s->n_preferred_kex++] = NULL;
6385 * Set up the preferred ciphers. (NULL => warn below here)
6387 s->n_preferred_ciphers = 0;
6388 for (i = 0; i < CIPHER_MAX; i++) {
6389 switch (conf_get_int_int(ssh->conf, CONF_ssh_cipherlist, i)) {
6390 case CIPHER_BLOWFISH:
6391 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_blowfish;
6394 if (conf_get_int(ssh->conf, CONF_ssh2_des_cbc)) {
6395 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_des;
6399 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_3des;
6402 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_aes;
6404 case CIPHER_ARCFOUR:
6405 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_arcfour;
6407 case CIPHER_CHACHA20:
6408 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_ccp;
6411 /* Flag for later. Don't bother if it's the last in
6413 if (i < CIPHER_MAX - 1) {
6414 s->preferred_ciphers[s->n_preferred_ciphers++] = NULL;
6421 * Set up preferred compression.
6423 if (conf_get_int(ssh->conf, CONF_compression))
6424 s->preferred_comp = &ssh_zlib;
6426 s->preferred_comp = &ssh_comp_none;
6429 * Enable queueing of outgoing auth- or connection-layer
6430 * packets while we are in the middle of a key exchange.
6432 ssh->queueing = TRUE;
6435 * Flag that KEX is in progress.
6437 ssh->kex_in_progress = TRUE;
6439 for (i = 0; i < NKEXLIST; i++)
6440 for (j = 0; j < MAXKEXLIST; j++)
6441 s->kexlists[i][j].name = NULL;
6442 /* List key exchange algorithms. */
6444 for (i = 0; i < s->n_preferred_kex; i++) {
6445 const struct ssh_kexes *k = s->preferred_kex[i];
6446 if (!k) warn = TRUE;
6447 else for (j = 0; j < k->nkexes; j++) {
6448 alg = ssh2_kexinit_addalg(s->kexlists[KEXLIST_KEX],
6450 alg->u.kex.kex = k->list[j];
6451 alg->u.kex.warn = warn;
6454 /* List server host key algorithms. */
6455 if (!s->got_session_id) {
6457 * In the first key exchange, we list all the algorithms
6458 * we're prepared to cope with, but prefer those algorithms
6459 * for which we have a host key for this host.
6461 for (i = 0; i < lenof(hostkey_algs); i++) {
6462 if (have_ssh_host_key(ssh->savedhost, ssh->savedport,
6463 hostkey_algs[i]->keytype)) {
6464 alg = ssh2_kexinit_addalg(s->kexlists[KEXLIST_HOSTKEY],
6465 hostkey_algs[i]->name);
6466 alg->u.hostkey = hostkey_algs[i];
6469 for (i = 0; i < lenof(hostkey_algs); i++) {
6470 alg = ssh2_kexinit_addalg(s->kexlists[KEXLIST_HOSTKEY],
6471 hostkey_algs[i]->name);
6472 alg->u.hostkey = hostkey_algs[i];
6476 * In subsequent key exchanges, we list only the kex
6477 * algorithm that was selected in the first key exchange,
6478 * so that we keep getting the same host key and hence
6479 * don't have to interrupt the user's session to ask for
6483 alg = ssh2_kexinit_addalg(s->kexlists[KEXLIST_HOSTKEY],
6484 ssh->hostkey->name);
6485 alg->u.hostkey = ssh->hostkey;
6487 /* List encryption algorithms (client->server then server->client). */
6488 for (k = KEXLIST_CSCIPHER; k <= KEXLIST_SCCIPHER; k++) {
6491 alg = ssh2_kexinit_addalg(s->kexlists[k], "none");
6492 alg->u.cipher.cipher = NULL;
6493 alg->u.cipher.warn = warn;
6494 #endif /* FUZZING */
6495 for (i = 0; i < s->n_preferred_ciphers; i++) {
6496 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
6497 if (!c) warn = TRUE;
6498 else for (j = 0; j < c->nciphers; j++) {
6499 alg = ssh2_kexinit_addalg(s->kexlists[k],
6501 alg->u.cipher.cipher = c->list[j];
6502 alg->u.cipher.warn = warn;
6506 /* List MAC algorithms (client->server then server->client). */
6507 for (j = KEXLIST_CSMAC; j <= KEXLIST_SCMAC; j++) {
6509 alg = ssh2_kexinit_addalg(s->kexlists[j], "none");
6510 alg->u.mac.mac = NULL;
6511 alg->u.mac.etm = FALSE;
6512 #endif /* FUZZING */
6513 for (i = 0; i < s->nmacs; i++) {
6514 alg = ssh2_kexinit_addalg(s->kexlists[j], s->maclist[i]->name);
6515 alg->u.mac.mac = s->maclist[i];
6516 alg->u.mac.etm = FALSE;
6518 for (i = 0; i < s->nmacs; i++)
6519 /* For each MAC, there may also be an ETM version,
6520 * which we list second. */
6521 if (s->maclist[i]->etm_name) {
6522 alg = ssh2_kexinit_addalg(s->kexlists[j],
6523 s->maclist[i]->etm_name);
6524 alg->u.mac.mac = s->maclist[i];
6525 alg->u.mac.etm = TRUE;
6528 /* List client->server compression algorithms,
6529 * then server->client compression algorithms. (We use the
6530 * same set twice.) */
6531 for (j = KEXLIST_CSCOMP; j <= KEXLIST_SCCOMP; j++) {
6532 assert(lenof(compressions) > 1);
6533 /* Prefer non-delayed versions */
6534 alg = ssh2_kexinit_addalg(s->kexlists[j], s->preferred_comp->name);
6535 alg->u.comp = s->preferred_comp;
6536 /* We don't even list delayed versions of algorithms until
6537 * they're allowed to be used, to avoid a race. See the end of
6539 if (s->userauth_succeeded && s->preferred_comp->delayed_name) {
6540 alg = ssh2_kexinit_addalg(s->kexlists[j],
6541 s->preferred_comp->delayed_name);
6542 alg->u.comp = s->preferred_comp;
6544 for (i = 0; i < lenof(compressions); i++) {
6545 const struct ssh_compress *c = compressions[i];
6546 alg = ssh2_kexinit_addalg(s->kexlists[j], c->name);
6548 if (s->userauth_succeeded && c->delayed_name) {
6549 alg = ssh2_kexinit_addalg(s->kexlists[j], c->delayed_name);
6555 * Construct and send our key exchange packet.
6557 s->pktout = ssh2_pkt_init(SSH2_MSG_KEXINIT);
6558 for (i = 0; i < 16; i++)
6559 ssh2_pkt_addbyte(s->pktout, (unsigned char) random_byte());
6560 for (i = 0; i < NKEXLIST; i++) {
6561 ssh2_pkt_addstring_start(s->pktout);
6562 for (j = 0; j < MAXKEXLIST; j++) {
6563 if (s->kexlists[i][j].name == NULL) break;
6564 ssh2_pkt_addstring_commasep(s->pktout, s->kexlists[i][j].name);
6567 /* List client->server languages. Empty list. */
6568 ssh2_pkt_addstring_start(s->pktout);
6569 /* List server->client languages. Empty list. */
6570 ssh2_pkt_addstring_start(s->pktout);
6571 /* First KEX packet does _not_ follow, because we're not that brave. */
6572 ssh2_pkt_addbool(s->pktout, FALSE);
6574 ssh2_pkt_adduint32(s->pktout, 0);
6577 s->our_kexinitlen = s->pktout->length - 5;
6578 s->our_kexinit = snewn(s->our_kexinitlen, unsigned char);
6579 memcpy(s->our_kexinit, s->pktout->data + 5, s->our_kexinitlen);
6581 ssh2_pkt_send_noqueue(ssh, s->pktout);
6584 crWaitUntilV(pktin);
6587 * Now examine the other side's KEXINIT to see what we're up
6594 if (pktin->type != SSH2_MSG_KEXINIT) {
6595 bombout(("expected key exchange packet from server"));
6599 ssh->hostkey = NULL;
6600 s->cscipher_tobe = NULL;
6601 s->sccipher_tobe = NULL;
6602 s->csmac_tobe = NULL;
6603 s->scmac_tobe = NULL;
6604 s->cscomp_tobe = NULL;
6605 s->sccomp_tobe = NULL;
6606 s->warn_kex = s->warn_cscipher = s->warn_sccipher = FALSE;
6608 pktin->savedpos += 16; /* skip garbage cookie */
6611 for (i = 0; i < NKEXLIST; i++) {
6612 ssh_pkt_getstring(pktin, &str, &len);
6614 bombout(("KEXINIT packet was incomplete"));
6618 /* If we've already selected a cipher which requires a
6619 * particular MAC, then just select that, and don't even
6620 * bother looking through the server's KEXINIT string for
6622 if (i == KEXLIST_CSMAC && s->cscipher_tobe &&
6623 s->cscipher_tobe->required_mac) {
6624 s->csmac_tobe = s->cscipher_tobe->required_mac;
6625 s->csmac_etm_tobe = !!(s->csmac_tobe->etm_name);
6628 if (i == KEXLIST_SCMAC && s->sccipher_tobe &&
6629 s->sccipher_tobe->required_mac) {
6630 s->scmac_tobe = s->sccipher_tobe->required_mac;
6631 s->scmac_etm_tobe = !!(s->scmac_tobe->etm_name);
6635 for (j = 0; j < MAXKEXLIST; j++) {
6636 struct kexinit_algorithm *alg = &s->kexlists[i][j];
6637 if (alg->name == NULL) break;
6638 if (in_commasep_string(alg->name, str, len)) {
6639 /* We've found a matching algorithm. */
6640 if (i == KEXLIST_KEX || i == KEXLIST_HOSTKEY) {
6641 /* Check if we might need to ignore first kex pkt */
6643 !first_in_commasep_string(alg->name, str, len))
6646 if (i == KEXLIST_KEX) {
6647 ssh->kex = alg->u.kex.kex;
6648 s->warn_kex = alg->u.kex.warn;
6649 } else if (i == KEXLIST_HOSTKEY) {
6650 ssh->hostkey = alg->u.hostkey;
6651 } else if (i == KEXLIST_CSCIPHER) {
6652 s->cscipher_tobe = alg->u.cipher.cipher;
6653 s->warn_cscipher = alg->u.cipher.warn;
6654 } else if (i == KEXLIST_SCCIPHER) {
6655 s->sccipher_tobe = alg->u.cipher.cipher;
6656 s->warn_sccipher = alg->u.cipher.warn;
6657 } else if (i == KEXLIST_CSMAC) {
6658 s->csmac_tobe = alg->u.mac.mac;
6659 s->csmac_etm_tobe = alg->u.mac.etm;
6660 } else if (i == KEXLIST_SCMAC) {
6661 s->scmac_tobe = alg->u.mac.mac;
6662 s->scmac_etm_tobe = alg->u.mac.etm;
6663 } else if (i == KEXLIST_CSCOMP) {
6664 s->cscomp_tobe = alg->u.comp;
6665 } else if (i == KEXLIST_SCCOMP) {
6666 s->sccomp_tobe = alg->u.comp;
6670 if ((i == KEXLIST_CSCOMP || i == KEXLIST_SCCOMP) &&
6671 in_commasep_string(alg->u.comp->delayed_name, str, len))
6672 s->pending_compression = TRUE; /* try this later */
6674 bombout(("Couldn't agree a %s ((available: %.*s)",
6675 kexlist_descr[i], len, str));
6680 if (s->pending_compression) {
6681 logevent("Server supports delayed compression; "
6682 "will try this later");
6684 ssh_pkt_getstring(pktin, &str, &len); /* client->server language */
6685 ssh_pkt_getstring(pktin, &str, &len); /* server->client language */
6686 s->ignorepkt = ssh2_pkt_getbool(pktin) && !s->guessok;
6688 ssh->exhash = ssh->kex->hash->init();
6689 hash_string(ssh->kex->hash, ssh->exhash, ssh->v_c, strlen(ssh->v_c));
6690 hash_string(ssh->kex->hash, ssh->exhash, ssh->v_s, strlen(ssh->v_s));
6691 hash_string(ssh->kex->hash, ssh->exhash,
6692 s->our_kexinit, s->our_kexinitlen);
6693 sfree(s->our_kexinit);
6694 /* Include the type byte in the hash of server's KEXINIT */
6695 hash_string(ssh->kex->hash, ssh->exhash,
6696 pktin->body - 1, pktin->length + 1);
6699 ssh_set_frozen(ssh, 1);
6700 s->dlgret = askalg(ssh->frontend, "key-exchange algorithm",
6702 ssh_dialog_callback, ssh);
6703 if (s->dlgret < 0) {
6707 bombout(("Unexpected data from server while"
6708 " waiting for user response"));
6711 } while (pktin || inlen > 0);
6712 s->dlgret = ssh->user_response;
6714 ssh_set_frozen(ssh, 0);
6715 if (s->dlgret == 0) {
6716 ssh_disconnect(ssh, "User aborted at kex warning", NULL,
6722 if (s->warn_cscipher) {
6723 ssh_set_frozen(ssh, 1);
6724 s->dlgret = askalg(ssh->frontend,
6725 "client-to-server cipher",
6726 s->cscipher_tobe->name,
6727 ssh_dialog_callback, ssh);
6728 if (s->dlgret < 0) {
6732 bombout(("Unexpected data from server while"
6733 " waiting for user response"));
6736 } while (pktin || inlen > 0);
6737 s->dlgret = ssh->user_response;
6739 ssh_set_frozen(ssh, 0);
6740 if (s->dlgret == 0) {
6741 ssh_disconnect(ssh, "User aborted at cipher warning", NULL,
6747 if (s->warn_sccipher) {
6748 ssh_set_frozen(ssh, 1);
6749 s->dlgret = askalg(ssh->frontend,
6750 "server-to-client cipher",
6751 s->sccipher_tobe->name,
6752 ssh_dialog_callback, ssh);
6753 if (s->dlgret < 0) {
6757 bombout(("Unexpected data from server while"
6758 " waiting for user response"));
6761 } while (pktin || inlen > 0);
6762 s->dlgret = ssh->user_response;
6764 ssh_set_frozen(ssh, 0);
6765 if (s->dlgret == 0) {
6766 ssh_disconnect(ssh, "User aborted at cipher warning", NULL,
6772 if (s->ignorepkt) /* first_kex_packet_follows */
6773 crWaitUntilV(pktin); /* Ignore packet */
6776 if (ssh->kex->main_type == KEXTYPE_DH) {
6778 * Work out the number of bits of key we will need from the
6779 * key exchange. We start with the maximum key length of
6785 csbits = s->cscipher_tobe ? s->cscipher_tobe->real_keybits : 0;
6786 scbits = s->sccipher_tobe ? s->sccipher_tobe->real_keybits : 0;
6787 s->nbits = (csbits > scbits ? csbits : scbits);
6789 /* The keys only have hlen-bit entropy, since they're based on
6790 * a hash. So cap the key size at hlen bits. */
6791 if (s->nbits > ssh->kex->hash->hlen * 8)
6792 s->nbits = ssh->kex->hash->hlen * 8;
6795 * If we're doing Diffie-Hellman group exchange, start by
6796 * requesting a group.
6798 if (dh_is_gex(ssh->kex)) {
6799 logevent("Doing Diffie-Hellman group exchange");
6800 ssh->pkt_kctx = SSH2_PKTCTX_DHGEX;
6802 * Work out how big a DH group we will need to allow that
6805 s->pbits = 512 << ((s->nbits - 1) / 64);
6806 if (s->pbits < DH_MIN_SIZE)
6807 s->pbits = DH_MIN_SIZE;
6808 if (s->pbits > DH_MAX_SIZE)
6809 s->pbits = DH_MAX_SIZE;
6810 if ((ssh->remote_bugs & BUG_SSH2_OLDGEX)) {
6811 s->pktout = ssh2_pkt_init(SSH2_MSG_KEX_DH_GEX_REQUEST_OLD);
6812 ssh2_pkt_adduint32(s->pktout, s->pbits);
6814 s->pktout = ssh2_pkt_init(SSH2_MSG_KEX_DH_GEX_REQUEST);
6815 ssh2_pkt_adduint32(s->pktout, DH_MIN_SIZE);
6816 ssh2_pkt_adduint32(s->pktout, s->pbits);
6817 ssh2_pkt_adduint32(s->pktout, DH_MAX_SIZE);
6819 ssh2_pkt_send_noqueue(ssh, s->pktout);
6821 crWaitUntilV(pktin);
6822 if (pktin->type != SSH2_MSG_KEX_DH_GEX_GROUP) {
6823 bombout(("expected key exchange group packet from server"));
6826 s->p = ssh2_pkt_getmp(pktin);
6827 s->g = ssh2_pkt_getmp(pktin);
6828 if (!s->p || !s->g) {
6829 bombout(("unable to read mp-ints from incoming group packet"));
6832 ssh->kex_ctx = dh_setup_gex(s->p, s->g);
6833 s->kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT;
6834 s->kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY;
6836 ssh->pkt_kctx = SSH2_PKTCTX_DHGROUP;
6837 ssh->kex_ctx = dh_setup_group(ssh->kex);
6838 s->kex_init_value = SSH2_MSG_KEXDH_INIT;
6839 s->kex_reply_value = SSH2_MSG_KEXDH_REPLY;
6840 logeventf(ssh, "Using Diffie-Hellman with standard group \"%s\"",
6841 ssh->kex->groupname);
6844 logeventf(ssh, "Doing Diffie-Hellman key exchange with hash %s",
6845 ssh->kex->hash->text_name);
6847 * Now generate and send e for Diffie-Hellman.
6849 set_busy_status(ssh->frontend, BUSY_CPU); /* this can take a while */
6850 s->e = dh_create_e(ssh->kex_ctx, s->nbits * 2);
6851 s->pktout = ssh2_pkt_init(s->kex_init_value);
6852 ssh2_pkt_addmp(s->pktout, s->e);
6853 ssh2_pkt_send_noqueue(ssh, s->pktout);
6855 set_busy_status(ssh->frontend, BUSY_WAITING); /* wait for server */
6856 crWaitUntilV(pktin);
6857 if (pktin->type != s->kex_reply_value) {
6858 bombout(("expected key exchange reply packet from server"));
6861 set_busy_status(ssh->frontend, BUSY_CPU); /* cogitate */
6862 ssh_pkt_getstring(pktin, &s->hostkeydata, &s->hostkeylen);
6863 if (!s->hostkeydata) {
6864 bombout(("unable to parse key exchange reply packet"));
6867 s->hkey = ssh->hostkey->newkey(ssh->hostkey,
6868 s->hostkeydata, s->hostkeylen);
6869 s->f = ssh2_pkt_getmp(pktin);
6871 bombout(("unable to parse key exchange reply packet"));
6874 ssh_pkt_getstring(pktin, &s->sigdata, &s->siglen);
6876 bombout(("unable to parse key exchange reply packet"));
6881 const char *err = dh_validate_f(ssh->kex_ctx, s->f);
6883 bombout(("key exchange reply failed validation: %s", err));
6887 s->K = dh_find_K(ssh->kex_ctx, s->f);
6889 /* We assume everything from now on will be quick, and it might
6890 * involve user interaction. */
6891 set_busy_status(ssh->frontend, BUSY_NOT);
6893 hash_string(ssh->kex->hash, ssh->exhash, s->hostkeydata, s->hostkeylen);
6894 if (dh_is_gex(ssh->kex)) {
6895 if (!(ssh->remote_bugs & BUG_SSH2_OLDGEX))
6896 hash_uint32(ssh->kex->hash, ssh->exhash, DH_MIN_SIZE);
6897 hash_uint32(ssh->kex->hash, ssh->exhash, s->pbits);
6898 if (!(ssh->remote_bugs & BUG_SSH2_OLDGEX))
6899 hash_uint32(ssh->kex->hash, ssh->exhash, DH_MAX_SIZE);
6900 hash_mpint(ssh->kex->hash, ssh->exhash, s->p);
6901 hash_mpint(ssh->kex->hash, ssh->exhash, s->g);
6903 hash_mpint(ssh->kex->hash, ssh->exhash, s->e);
6904 hash_mpint(ssh->kex->hash, ssh->exhash, s->f);
6906 dh_cleanup(ssh->kex_ctx);
6908 if (dh_is_gex(ssh->kex)) {
6912 } else if (ssh->kex->main_type == KEXTYPE_ECDH) {
6914 logeventf(ssh, "Doing ECDH key exchange with curve %s and hash %s",
6915 ssh_ecdhkex_curve_textname(ssh->kex),
6916 ssh->kex->hash->text_name);
6917 ssh->pkt_kctx = SSH2_PKTCTX_ECDHKEX;
6919 s->eckey = ssh_ecdhkex_newkey(ssh->kex);
6921 bombout(("Unable to generate key for ECDH"));
6927 int publicPointLength;
6928 publicPoint = ssh_ecdhkex_getpublic(s->eckey, &publicPointLength);
6930 ssh_ecdhkex_freekey(s->eckey);
6931 bombout(("Unable to encode public key for ECDH"));
6934 s->pktout = ssh2_pkt_init(SSH2_MSG_KEX_ECDH_INIT);
6935 ssh2_pkt_addstring_start(s->pktout);
6936 ssh2_pkt_addstring_data(s->pktout, publicPoint, publicPointLength);
6940 ssh2_pkt_send_noqueue(ssh, s->pktout);
6942 crWaitUntilV(pktin);
6943 if (pktin->type != SSH2_MSG_KEX_ECDH_REPLY) {
6944 ssh_ecdhkex_freekey(s->eckey);
6945 bombout(("expected ECDH reply packet from server"));
6949 ssh_pkt_getstring(pktin, &s->hostkeydata, &s->hostkeylen);
6950 if (!s->hostkeydata) {
6951 bombout(("unable to parse ECDH reply packet"));
6954 hash_string(ssh->kex->hash, ssh->exhash, s->hostkeydata, s->hostkeylen);
6955 s->hkey = ssh->hostkey->newkey(ssh->hostkey,
6956 s->hostkeydata, s->hostkeylen);
6960 int publicPointLength;
6961 publicPoint = ssh_ecdhkex_getpublic(s->eckey, &publicPointLength);
6963 ssh_ecdhkex_freekey(s->eckey);
6964 bombout(("Unable to encode public key for ECDH hash"));
6967 hash_string(ssh->kex->hash, ssh->exhash,
6968 publicPoint, publicPointLength);
6975 ssh_pkt_getstring(pktin, &keydata, &keylen);
6977 bombout(("unable to parse ECDH reply packet"));
6980 hash_string(ssh->kex->hash, ssh->exhash, keydata, keylen);
6981 s->K = ssh_ecdhkex_getkey(s->eckey, keydata, keylen);
6983 ssh_ecdhkex_freekey(s->eckey);
6984 bombout(("point received in ECDH was not valid"));
6989 ssh_pkt_getstring(pktin, &s->sigdata, &s->siglen);
6991 bombout(("unable to parse key exchange reply packet"));
6995 ssh_ecdhkex_freekey(s->eckey);
6997 logeventf(ssh, "Doing RSA key exchange with hash %s",
6998 ssh->kex->hash->text_name);
6999 ssh->pkt_kctx = SSH2_PKTCTX_RSAKEX;
7001 * RSA key exchange. First expect a KEXRSA_PUBKEY packet
7004 crWaitUntilV(pktin);
7005 if (pktin->type != SSH2_MSG_KEXRSA_PUBKEY) {
7006 bombout(("expected RSA public key packet from server"));
7010 ssh_pkt_getstring(pktin, &s->hostkeydata, &s->hostkeylen);
7011 if (!s->hostkeydata) {
7012 bombout(("unable to parse RSA public key packet"));
7015 hash_string(ssh->kex->hash, ssh->exhash,
7016 s->hostkeydata, s->hostkeylen);
7017 s->hkey = ssh->hostkey->newkey(ssh->hostkey,
7018 s->hostkeydata, s->hostkeylen);
7022 ssh_pkt_getstring(pktin, &keydata, &s->rsakeylen);
7024 bombout(("unable to parse RSA public key packet"));
7027 s->rsakeydata = snewn(s->rsakeylen, char);
7028 memcpy(s->rsakeydata, keydata, s->rsakeylen);
7031 s->rsakey = ssh_rsakex_newkey(s->rsakeydata, s->rsakeylen);
7033 sfree(s->rsakeydata);
7034 bombout(("unable to parse RSA public key from server"));
7038 hash_string(ssh->kex->hash, ssh->exhash, s->rsakeydata, s->rsakeylen);
7041 * Next, set up a shared secret K, of precisely KLEN -
7042 * 2*HLEN - 49 bits, where KLEN is the bit length of the
7043 * RSA key modulus and HLEN is the bit length of the hash
7047 int klen = ssh_rsakex_klen(s->rsakey);
7048 int nbits = klen - (2*ssh->kex->hash->hlen*8 + 49);
7050 unsigned char *kstr1, *kstr2, *outstr;
7051 int kstr1len, kstr2len, outstrlen;
7053 s->K = bn_power_2(nbits - 1);
7055 for (i = 0; i < nbits; i++) {
7057 byte = random_byte();
7059 bignum_set_bit(s->K, i, (byte >> (i & 7)) & 1);
7063 * Encode this as an mpint.
7065 kstr1 = ssh2_mpint_fmt(s->K, &kstr1len);
7066 kstr2 = snewn(kstr2len = 4 + kstr1len, unsigned char);
7067 PUT_32BIT(kstr2, kstr1len);
7068 memcpy(kstr2 + 4, kstr1, kstr1len);
7071 * Encrypt it with the given RSA key.
7073 outstrlen = (klen + 7) / 8;
7074 outstr = snewn(outstrlen, unsigned char);
7075 ssh_rsakex_encrypt(ssh->kex->hash, kstr2, kstr2len,
7076 outstr, outstrlen, s->rsakey);
7079 * And send it off in a return packet.
7081 s->pktout = ssh2_pkt_init(SSH2_MSG_KEXRSA_SECRET);
7082 ssh2_pkt_addstring_start(s->pktout);
7083 ssh2_pkt_addstring_data(s->pktout, (char *)outstr, outstrlen);
7084 ssh2_pkt_send_noqueue(ssh, s->pktout);
7086 hash_string(ssh->kex->hash, ssh->exhash, outstr, outstrlen);
7093 ssh_rsakex_freekey(s->rsakey);
7095 crWaitUntilV(pktin);
7096 if (pktin->type != SSH2_MSG_KEXRSA_DONE) {
7097 sfree(s->rsakeydata);
7098 bombout(("expected signature packet from server"));
7102 ssh_pkt_getstring(pktin, &s->sigdata, &s->siglen);
7104 bombout(("unable to parse signature packet"));
7108 sfree(s->rsakeydata);
7111 hash_mpint(ssh->kex->hash, ssh->exhash, s->K);
7112 assert(ssh->kex->hash->hlen <= sizeof(s->exchange_hash));
7113 ssh->kex->hash->final(ssh->exhash, s->exchange_hash);
7115 ssh->kex_ctx = NULL;
7118 debug(("Exchange hash is:\n"));
7119 dmemdump(s->exchange_hash, ssh->kex->hash->hlen);
7123 bombout(("Server's host key is invalid"));
7127 if (!ssh->hostkey->verifysig(s->hkey, s->sigdata, s->siglen,
7128 (char *)s->exchange_hash,
7129 ssh->kex->hash->hlen)) {
7131 bombout(("Server's host key did not match the signature supplied"));
7136 s->keystr = ssh->hostkey->fmtkey(s->hkey);
7137 if (!s->got_session_id) {
7139 * Authenticate remote host: verify host key. (We've already
7140 * checked the signature of the exchange hash.)
7142 s->fingerprint = ssh2_fingerprint(ssh->hostkey, s->hkey);
7143 logevent("Host key fingerprint is:");
7144 logevent(s->fingerprint);
7145 /* First check against manually configured host keys. */
7146 s->dlgret = verify_ssh_manual_host_key(ssh, s->fingerprint,
7147 ssh->hostkey, s->hkey);
7148 if (s->dlgret == 0) { /* did not match */
7149 bombout(("Host key did not appear in manually configured list"));
7151 } else if (s->dlgret < 0) { /* none configured; use standard handling */
7152 ssh_set_frozen(ssh, 1);
7153 s->dlgret = verify_ssh_host_key(ssh->frontend,
7154 ssh->savedhost, ssh->savedport,
7155 ssh->hostkey->keytype, s->keystr,
7157 ssh_dialog_callback, ssh);
7161 if (s->dlgret < 0) {
7165 bombout(("Unexpected data from server while waiting"
7166 " for user host key response"));
7169 } while (pktin || inlen > 0);
7170 s->dlgret = ssh->user_response;
7172 ssh_set_frozen(ssh, 0);
7173 if (s->dlgret == 0) {
7174 ssh_disconnect(ssh, "Aborted at host key verification", NULL,
7179 sfree(s->fingerprint);
7181 * Save this host key, to check against the one presented in
7182 * subsequent rekeys.
7184 ssh->hostkey_str = s->keystr;
7187 * In a rekey, we never present an interactive host key
7188 * verification request to the user. Instead, we simply
7189 * enforce that the key we're seeing this time is identical to
7190 * the one we saw before.
7192 if (strcmp(ssh->hostkey_str, s->keystr)) {
7194 bombout(("Host key was different in repeat key exchange"));
7200 ssh->hostkey->freekey(s->hkey);
7203 * The exchange hash from the very first key exchange is also
7204 * the session id, used in session key construction and
7207 if (!s->got_session_id) {
7208 assert(sizeof(s->exchange_hash) <= sizeof(ssh->v2_session_id));
7209 memcpy(ssh->v2_session_id, s->exchange_hash,
7210 sizeof(s->exchange_hash));
7211 ssh->v2_session_id_len = ssh->kex->hash->hlen;
7212 assert(ssh->v2_session_id_len <= sizeof(ssh->v2_session_id));
7213 s->got_session_id = TRUE;
7217 * Send SSH2_MSG_NEWKEYS.
7219 s->pktout = ssh2_pkt_init(SSH2_MSG_NEWKEYS);
7220 ssh2_pkt_send_noqueue(ssh, s->pktout);
7221 ssh->outgoing_data_size = 0; /* start counting from here */
7224 * We've sent client NEWKEYS, so create and initialise
7225 * client-to-server session keys.
7227 if (ssh->cs_cipher_ctx)
7228 ssh->cscipher->free_context(ssh->cs_cipher_ctx);
7229 ssh->cscipher = s->cscipher_tobe;
7230 if (ssh->cscipher) ssh->cs_cipher_ctx = ssh->cscipher->make_context();
7232 if (ssh->cs_mac_ctx)
7233 ssh->csmac->free_context(ssh->cs_mac_ctx);
7234 ssh->csmac = s->csmac_tobe;
7235 ssh->csmac_etm = s->csmac_etm_tobe;
7237 ssh->cs_mac_ctx = ssh->csmac->make_context(ssh->cs_cipher_ctx);
7239 if (ssh->cs_comp_ctx)
7240 ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
7241 ssh->cscomp = s->cscomp_tobe;
7242 ssh->cs_comp_ctx = ssh->cscomp->compress_init();
7245 * Set IVs on client-to-server keys. Here we use the exchange
7246 * hash from the _first_ key exchange.
7248 if (ssh->cscipher) {
7251 key = ssh2_mkkey(ssh, s->K, s->exchange_hash, 'C',
7252 ssh->cscipher->padded_keybytes);
7253 ssh->cscipher->setkey(ssh->cs_cipher_ctx, key);
7254 smemclr(key, ssh->cscipher->padded_keybytes);
7257 key = ssh2_mkkey(ssh, s->K, s->exchange_hash, 'A',
7258 ssh->cscipher->blksize);
7259 ssh->cscipher->setiv(ssh->cs_cipher_ctx, key);
7260 smemclr(key, ssh->cscipher->blksize);
7266 key = ssh2_mkkey(ssh, s->K, s->exchange_hash, 'E',
7267 ssh->csmac->keylen);
7268 ssh->csmac->setkey(ssh->cs_mac_ctx, key);
7269 smemclr(key, ssh->csmac->keylen);
7274 logeventf(ssh, "Initialised %.200s client->server encryption",
7275 ssh->cscipher->text_name);
7277 logeventf(ssh, "Initialised %.200s client->server MAC algorithm%s%s",
7278 ssh->csmac->text_name,
7279 ssh->csmac_etm ? " (in ETM mode)" : "",
7280 ssh->cscipher->required_mac ? " (required by cipher)" : "");
7281 if (ssh->cscomp->text_name)
7282 logeventf(ssh, "Initialised %s compression",
7283 ssh->cscomp->text_name);
7286 * Now our end of the key exchange is complete, we can send all
7287 * our queued higher-layer packets.
7289 ssh->queueing = FALSE;
7290 ssh2_pkt_queuesend(ssh);
7293 * Expect SSH2_MSG_NEWKEYS from server.
7295 crWaitUntilV(pktin);
7296 if (pktin->type != SSH2_MSG_NEWKEYS) {
7297 bombout(("expected new-keys packet from server"));
7300 ssh->incoming_data_size = 0; /* start counting from here */
7303 * We've seen server NEWKEYS, so create and initialise
7304 * server-to-client session keys.
7306 if (ssh->sc_cipher_ctx)
7307 ssh->sccipher->free_context(ssh->sc_cipher_ctx);
7308 if (s->sccipher_tobe) {
7309 ssh->sccipher = s->sccipher_tobe;
7310 ssh->sc_cipher_ctx = ssh->sccipher->make_context();
7313 if (ssh->sc_mac_ctx)
7314 ssh->scmac->free_context(ssh->sc_mac_ctx);
7315 if (s->scmac_tobe) {
7316 ssh->scmac = s->scmac_tobe;
7317 ssh->scmac_etm = s->scmac_etm_tobe;
7318 ssh->sc_mac_ctx = ssh->scmac->make_context(ssh->sc_cipher_ctx);
7321 if (ssh->sc_comp_ctx)
7322 ssh->sccomp->decompress_cleanup(ssh->sc_comp_ctx);
7323 ssh->sccomp = s->sccomp_tobe;
7324 ssh->sc_comp_ctx = ssh->sccomp->decompress_init();
7327 * Set IVs on server-to-client keys. Here we use the exchange
7328 * hash from the _first_ key exchange.
7330 if (ssh->sccipher) {
7333 key = ssh2_mkkey(ssh, s->K, s->exchange_hash, 'D',
7334 ssh->sccipher->padded_keybytes);
7335 ssh->sccipher->setkey(ssh->sc_cipher_ctx, key);
7336 smemclr(key, ssh->sccipher->padded_keybytes);
7339 key = ssh2_mkkey(ssh, s->K, s->exchange_hash, 'B',
7340 ssh->sccipher->blksize);
7341 ssh->sccipher->setiv(ssh->sc_cipher_ctx, key);
7342 smemclr(key, ssh->sccipher->blksize);
7348 key = ssh2_mkkey(ssh, s->K, s->exchange_hash, 'F',
7349 ssh->scmac->keylen);
7350 ssh->scmac->setkey(ssh->sc_mac_ctx, key);
7351 smemclr(key, ssh->scmac->keylen);
7355 logeventf(ssh, "Initialised %.200s server->client encryption",
7356 ssh->sccipher->text_name);
7358 logeventf(ssh, "Initialised %.200s server->client MAC algorithm%s%s",
7359 ssh->scmac->text_name,
7360 ssh->scmac_etm ? " (in ETM mode)" : "",
7361 ssh->sccipher->required_mac ? " (required by cipher)" : "");
7362 if (ssh->sccomp->text_name)
7363 logeventf(ssh, "Initialised %s decompression",
7364 ssh->sccomp->text_name);
7367 * Free shared secret.
7372 * Key exchange is over. Loop straight back round if we have a
7373 * deferred rekey reason.
7375 if (ssh->deferred_rekey_reason) {
7376 logevent(ssh->deferred_rekey_reason);
7378 ssh->deferred_rekey_reason = NULL;
7379 goto begin_key_exchange;
7383 * Otherwise, schedule a timer for our next rekey.
7385 ssh->kex_in_progress = FALSE;
7386 ssh->last_rekey = GETTICKCOUNT();
7387 if (conf_get_int(ssh->conf, CONF_ssh_rekey_time) != 0)
7388 ssh->next_rekey = schedule_timer(conf_get_int(ssh->conf, CONF_ssh_rekey_time)*60*TICKSPERSEC,
7392 * Now we're encrypting. Begin returning 1 to the protocol main
7393 * function so that other things can run on top of the
7394 * transport. If we ever see a KEXINIT, we must go back to the
7397 * We _also_ go back to the start if we see pktin==NULL and
7398 * inlen negative, because this is a special signal meaning
7399 * `initiate client-driven rekey', and `in' contains a message
7400 * giving the reason for the rekey.
7402 * inlen==-1 means always initiate a rekey;
7403 * inlen==-2 means that userauth has completed successfully and
7404 * we should consider rekeying (for delayed compression).
7406 while (!((pktin && pktin->type == SSH2_MSG_KEXINIT) ||
7407 (!pktin && inlen < 0))) {
7409 if (!ssh->protocol_initial_phase_done) {
7410 ssh->protocol_initial_phase_done = TRUE;
7412 * Allow authconn to initialise itself.
7414 do_ssh2_authconn(ssh, NULL, 0, NULL);
7419 logevent("Server initiated key re-exchange");
7423 * authconn has seen a USERAUTH_SUCCEEDED. Time to enable
7424 * delayed compression, if it's available.
7426 * draft-miller-secsh-compression-delayed-00 says that you
7427 * negotiate delayed compression in the first key exchange, and
7428 * both sides start compressing when the server has sent
7429 * USERAUTH_SUCCESS. This has a race condition -- the server
7430 * can't know when the client has seen it, and thus which incoming
7431 * packets it should treat as compressed.
7433 * Instead, we do the initial key exchange without offering the
7434 * delayed methods, but note if the server offers them; when we
7435 * get here, if a delayed method was available that was higher
7436 * on our list than what we got, we initiate a rekey in which we
7437 * _do_ list the delayed methods (and hopefully get it as a
7438 * result). Subsequent rekeys will do the same.
7440 assert(!s->userauth_succeeded); /* should only happen once */
7441 s->userauth_succeeded = TRUE;
7442 if (!s->pending_compression)
7443 /* Can't see any point rekeying. */
7444 goto wait_for_rekey; /* this is utterly horrid */
7445 /* else fall through to rekey... */
7446 s->pending_compression = FALSE;
7449 * Now we've decided to rekey.
7451 * Special case: if the server bug is set that doesn't
7452 * allow rekeying, we give a different log message and
7453 * continue waiting. (If such a server _initiates_ a rekey,
7454 * we process it anyway!)
7456 if ((ssh->remote_bugs & BUG_SSH2_REKEY)) {
7457 logeventf(ssh, "Server bug prevents key re-exchange (%s)",
7459 /* Reset the counters, so that at least this message doesn't
7460 * hit the event log _too_ often. */
7461 ssh->outgoing_data_size = 0;
7462 ssh->incoming_data_size = 0;
7463 if (conf_get_int(ssh->conf, CONF_ssh_rekey_time) != 0) {
7465 schedule_timer(conf_get_int(ssh->conf, CONF_ssh_rekey_time)*60*TICKSPERSEC,
7468 goto wait_for_rekey; /* this is still utterly horrid */
7470 logeventf(ssh, "Initiating key re-exchange (%s)", (char *)in);
7473 goto begin_key_exchange;
7479 * Add data to an SSH-2 channel output buffer.
7481 static void ssh2_add_channel_data(struct ssh_channel *c, const char *buf,
7484 bufchain_add(&c->v.v2.outbuffer, buf, len);
7488 * Attempt to send data on an SSH-2 channel.
7490 static int ssh2_try_send(struct ssh_channel *c)
7493 struct Packet *pktout;
7496 while (c->v.v2.remwindow > 0 && bufchain_size(&c->v.v2.outbuffer) > 0) {
7499 bufchain_prefix(&c->v.v2.outbuffer, &data, &len);
7500 if ((unsigned)len > c->v.v2.remwindow)
7501 len = c->v.v2.remwindow;
7502 if ((unsigned)len > c->v.v2.remmaxpkt)
7503 len = c->v.v2.remmaxpkt;
7504 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_DATA);
7505 ssh2_pkt_adduint32(pktout, c->remoteid);
7506 ssh2_pkt_addstring_start(pktout);
7507 ssh2_pkt_addstring_data(pktout, data, len);
7508 ssh2_pkt_send(ssh, pktout);
7509 bufchain_consume(&c->v.v2.outbuffer, len);
7510 c->v.v2.remwindow -= len;
7514 * After having sent as much data as we can, return the amount
7517 ret = bufchain_size(&c->v.v2.outbuffer);
7520 * And if there's no data pending but we need to send an EOF, send
7523 if (!ret && c->pending_eof)
7524 ssh_channel_try_eof(c);
7529 static void ssh2_try_send_and_unthrottle(Ssh ssh, struct ssh_channel *c)
7532 if (c->closes & CLOSES_SENT_EOF)
7533 return; /* don't send on channels we've EOFed */
7534 bufsize = ssh2_try_send(c);
7537 case CHAN_MAINSESSION:
7538 /* stdin need not receive an unthrottle
7539 * notification since it will be polled */
7542 x11_unthrottle(c->u.x11.xconn);
7545 /* agent sockets are request/response and need no
7546 * buffer management */
7549 pfd_unthrottle(c->u.pfd.pf);
7555 static int ssh_is_simple(Ssh ssh)
7558 * We use the 'simple' variant of the SSH protocol if we're asked
7559 * to, except not if we're also doing connection-sharing (either
7560 * tunnelling our packets over an upstream or expecting to be
7561 * tunnelled over ourselves), since then the assumption that we
7562 * have only one channel to worry about is not true after all.
7564 return (conf_get_int(ssh->conf, CONF_ssh_simple) &&
7565 !ssh->bare_connection && !ssh->connshare);
7569 * Set up most of a new ssh_channel for SSH-2.
7571 static void ssh2_channel_init(struct ssh_channel *c)
7574 c->localid = alloc_channel_id(ssh);
7576 c->pending_eof = FALSE;
7577 c->throttling_conn = FALSE;
7578 c->v.v2.locwindow = c->v.v2.locmaxwin = c->v.v2.remlocwin =
7579 ssh_is_simple(ssh) ? OUR_V2_BIGWIN : OUR_V2_WINSIZE;
7580 c->v.v2.chanreq_head = NULL;
7581 c->v.v2.throttle_state = UNTHROTTLED;
7582 bufchain_init(&c->v.v2.outbuffer);
7586 * Construct the common parts of a CHANNEL_OPEN.
7588 static struct Packet *ssh2_chanopen_init(struct ssh_channel *c,
7591 struct Packet *pktout;
7593 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN);
7594 ssh2_pkt_addstring(pktout, type);
7595 ssh2_pkt_adduint32(pktout, c->localid);
7596 ssh2_pkt_adduint32(pktout, c->v.v2.locwindow);/* our window size */
7597 ssh2_pkt_adduint32(pktout, OUR_V2_MAXPKT); /* our max pkt size */
7602 * CHANNEL_FAILURE doesn't come with any indication of what message
7603 * caused it, so we have to keep track of the outstanding
7604 * CHANNEL_REQUESTs ourselves.
7606 static void ssh2_queue_chanreq_handler(struct ssh_channel *c,
7607 cchandler_fn_t handler, void *ctx)
7609 struct outstanding_channel_request *ocr =
7610 snew(struct outstanding_channel_request);
7612 assert(!(c->closes & (CLOSES_SENT_CLOSE | CLOSES_RCVD_CLOSE)));
7613 ocr->handler = handler;
7616 if (!c->v.v2.chanreq_head)
7617 c->v.v2.chanreq_head = ocr;
7619 c->v.v2.chanreq_tail->next = ocr;
7620 c->v.v2.chanreq_tail = ocr;
7624 * Construct the common parts of a CHANNEL_REQUEST. If handler is not
7625 * NULL then a reply will be requested and the handler will be called
7626 * when it arrives. The returned packet is ready to have any
7627 * request-specific data added and be sent. Note that if a handler is
7628 * provided, it's essential that the request actually be sent.
7630 * The handler will usually be passed the response packet in pktin. If
7631 * pktin is NULL, this means that no reply will ever be forthcoming
7632 * (e.g. because the entire connection is being destroyed, or because
7633 * the server initiated channel closure before we saw the response)
7634 * and the handler should free any storage it's holding.
7636 static struct Packet *ssh2_chanreq_init(struct ssh_channel *c,
7638 cchandler_fn_t handler, void *ctx)
7640 struct Packet *pktout;
7642 assert(!(c->closes & (CLOSES_SENT_CLOSE | CLOSES_RCVD_CLOSE)));
7643 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
7644 ssh2_pkt_adduint32(pktout, c->remoteid);
7645 ssh2_pkt_addstring(pktout, type);
7646 ssh2_pkt_addbool(pktout, handler != NULL);
7647 if (handler != NULL)
7648 ssh2_queue_chanreq_handler(c, handler, ctx);
7653 * Potentially enlarge the window on an SSH-2 channel.
7655 static void ssh2_handle_winadj_response(struct ssh_channel *, struct Packet *,
7657 static void ssh2_set_window(struct ssh_channel *c, int newwin)
7662 * Never send WINDOW_ADJUST for a channel that the remote side has
7663 * already sent EOF on; there's no point, since it won't be
7664 * sending any more data anyway. Ditto if _we've_ already sent
7667 if (c->closes & (CLOSES_RCVD_EOF | CLOSES_SENT_CLOSE))
7671 * Also, never widen the window for an X11 channel when we're
7672 * still waiting to see its initial auth and may yet hand it off
7675 if (c->type == CHAN_X11 && c->u.x11.initial)
7679 * If the remote end has a habit of ignoring maxpkt, limit the
7680 * window so that it has no choice (assuming it doesn't ignore the
7683 if ((ssh->remote_bugs & BUG_SSH2_MAXPKT) && newwin > OUR_V2_MAXPKT)
7684 newwin = OUR_V2_MAXPKT;
7687 * Only send a WINDOW_ADJUST if there's significantly more window
7688 * available than the other end thinks there is. This saves us
7689 * sending a WINDOW_ADJUST for every character in a shell session.
7691 * "Significant" is arbitrarily defined as half the window size.
7693 if (newwin / 2 >= c->v.v2.locwindow) {
7694 struct Packet *pktout;
7698 * In order to keep track of how much window the client
7699 * actually has available, we'd like it to acknowledge each
7700 * WINDOW_ADJUST. We can't do that directly, so we accompany
7701 * it with a CHANNEL_REQUEST that has to be acknowledged.
7703 * This is only necessary if we're opening the window wide.
7704 * If we're not, then throughput is being constrained by
7705 * something other than the maximum window size anyway.
7707 if (newwin == c->v.v2.locmaxwin &&
7708 !(ssh->remote_bugs & BUG_CHOKES_ON_WINADJ)) {
7709 up = snew(unsigned);
7710 *up = newwin - c->v.v2.locwindow;
7711 pktout = ssh2_chanreq_init(c, "winadj@putty.projects.tartarus.org",
7712 ssh2_handle_winadj_response, up);
7713 ssh2_pkt_send(ssh, pktout);
7715 if (c->v.v2.throttle_state != UNTHROTTLED)
7716 c->v.v2.throttle_state = UNTHROTTLING;
7718 /* Pretend the WINDOW_ADJUST was acked immediately. */
7719 c->v.v2.remlocwin = newwin;
7720 c->v.v2.throttle_state = THROTTLED;
7722 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
7723 ssh2_pkt_adduint32(pktout, c->remoteid);
7724 ssh2_pkt_adduint32(pktout, newwin - c->v.v2.locwindow);
7725 ssh2_pkt_send(ssh, pktout);
7726 c->v.v2.locwindow = newwin;
7731 * Find the channel associated with a message. If there's no channel,
7732 * or it's not properly open, make a noise about it and return NULL.
7734 static struct ssh_channel *ssh2_channel_msg(Ssh ssh, struct Packet *pktin)
7736 unsigned localid = ssh_pkt_getuint32(pktin);
7737 struct ssh_channel *c;
7739 c = find234(ssh->channels, &localid, ssh_channelfind);
7741 (c->type != CHAN_SHARING && c->halfopen &&
7742 pktin->type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION &&
7743 pktin->type != SSH2_MSG_CHANNEL_OPEN_FAILURE)) {
7744 char *buf = dupprintf("Received %s for %s channel %u",
7745 ssh2_pkt_type(ssh->pkt_kctx, ssh->pkt_actx,
7747 c ? "half-open" : "nonexistent", localid);
7748 ssh_disconnect(ssh, NULL, buf, SSH2_DISCONNECT_PROTOCOL_ERROR, FALSE);
7755 static void ssh2_handle_winadj_response(struct ssh_channel *c,
7756 struct Packet *pktin, void *ctx)
7758 unsigned *sizep = ctx;
7761 * Winadj responses should always be failures. However, at least
7762 * one server ("boks_sshd") is known to return SUCCESS for channel
7763 * requests it's never heard of, such as "winadj@putty". Raised
7764 * with foxt.com as bug 090916-090424, but for the sake of a quiet
7765 * life, we don't worry about what kind of response we got.
7768 c->v.v2.remlocwin += *sizep;
7771 * winadj messages are only sent when the window is fully open, so
7772 * if we get an ack of one, we know any pending unthrottle is
7775 if (c->v.v2.throttle_state == UNTHROTTLING)
7776 c->v.v2.throttle_state = UNTHROTTLED;
7779 static void ssh2_msg_channel_response(Ssh ssh, struct Packet *pktin)
7781 struct ssh_channel *c = ssh2_channel_msg(ssh, pktin);
7782 struct outstanding_channel_request *ocr;
7785 if (c->type == CHAN_SHARING) {
7786 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
7787 pktin->body, pktin->length);
7790 ocr = c->v.v2.chanreq_head;
7792 ssh2_msg_unexpected(ssh, pktin);
7795 ocr->handler(c, pktin, ocr->ctx);
7796 c->v.v2.chanreq_head = ocr->next;
7799 * We may now initiate channel-closing procedures, if that
7800 * CHANNEL_REQUEST was the last thing outstanding before we send
7803 ssh2_channel_check_close(c);
7806 static void ssh2_msg_channel_window_adjust(Ssh ssh, struct Packet *pktin)
7808 struct ssh_channel *c;
7809 c = ssh2_channel_msg(ssh, pktin);
7812 if (c->type == CHAN_SHARING) {
7813 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
7814 pktin->body, pktin->length);
7817 if (!(c->closes & CLOSES_SENT_EOF)) {
7818 c->v.v2.remwindow += ssh_pkt_getuint32(pktin);
7819 ssh2_try_send_and_unthrottle(ssh, c);
7823 static void ssh2_msg_channel_data(Ssh ssh, struct Packet *pktin)
7827 struct ssh_channel *c;
7828 c = ssh2_channel_msg(ssh, pktin);
7831 if (c->type == CHAN_SHARING) {
7832 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
7833 pktin->body, pktin->length);
7836 if (pktin->type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
7837 ssh_pkt_getuint32(pktin) != SSH2_EXTENDED_DATA_STDERR)
7838 return; /* extended but not stderr */
7839 ssh_pkt_getstring(pktin, &data, &length);
7842 c->v.v2.locwindow -= length;
7843 c->v.v2.remlocwin -= length;
7845 case CHAN_MAINSESSION:
7847 from_backend(ssh->frontend, pktin->type ==
7848 SSH2_MSG_CHANNEL_EXTENDED_DATA,
7852 bufsize = x11_send(c->u.x11.xconn, data, length);
7855 bufsize = pfd_send(c->u.pfd.pf, data, length);
7858 while (length > 0) {
7859 if (c->u.a.lensofar < 4) {
7860 unsigned int l = min(4 - c->u.a.lensofar,
7862 memcpy(c->u.a.msglen + c->u.a.lensofar,
7866 c->u.a.lensofar += l;
7868 if (c->u.a.lensofar == 4) {
7870 4 + GET_32BIT(c->u.a.msglen);
7871 c->u.a.message = snewn(c->u.a.totallen,
7873 memcpy(c->u.a.message, c->u.a.msglen, 4);
7875 if (c->u.a.lensofar >= 4 && length > 0) {
7877 min(c->u.a.totallen - c->u.a.lensofar,
7879 memcpy(c->u.a.message + c->u.a.lensofar,
7883 c->u.a.lensofar += l;
7885 if (c->u.a.lensofar == c->u.a.totallen) {
7888 c->u.a.outstanding_requests++;
7889 if (agent_query(c->u.a.message,
7892 ssh_agentf_callback, c))
7893 ssh_agentf_callback(c, reply, replylen);
7894 sfree(c->u.a.message);
7895 c->u.a.message = NULL;
7896 c->u.a.lensofar = 0;
7903 * If it looks like the remote end hit the end of its window,
7904 * and we didn't want it to do that, think about using a
7907 if (c->v.v2.remlocwin <= 0 && c->v.v2.throttle_state == UNTHROTTLED &&
7908 c->v.v2.locmaxwin < 0x40000000)
7909 c->v.v2.locmaxwin += OUR_V2_WINSIZE;
7911 * If we are not buffering too much data,
7912 * enlarge the window again at the remote side.
7913 * If we are buffering too much, we may still
7914 * need to adjust the window if the server's
7917 ssh2_set_window(c, bufsize < c->v.v2.locmaxwin ?
7918 c->v.v2.locmaxwin - bufsize : 0);
7920 * If we're either buffering way too much data, or if we're
7921 * buffering anything at all and we're in "simple" mode,
7922 * throttle the whole channel.
7924 if ((bufsize > c->v.v2.locmaxwin || (ssh_is_simple(ssh) && bufsize>0))
7925 && !c->throttling_conn) {
7926 c->throttling_conn = 1;
7927 ssh_throttle_conn(ssh, +1);
7932 static void ssh_check_termination(Ssh ssh)
7934 if (ssh->version == 2 &&
7935 !conf_get_int(ssh->conf, CONF_ssh_no_shell) &&
7936 (ssh->channels && count234(ssh->channels) == 0) &&
7937 !(ssh->connshare && share_ndownstreams(ssh->connshare) > 0)) {
7939 * We used to send SSH_MSG_DISCONNECT here, because I'd
7940 * believed that _every_ conforming SSH-2 connection had to
7941 * end with a disconnect being sent by at least one side;
7942 * apparently I was wrong and it's perfectly OK to
7943 * unceremoniously slam the connection shut when you're done,
7944 * and indeed OpenSSH feels this is more polite than sending a
7945 * DISCONNECT. So now we don't.
7947 ssh_disconnect(ssh, "All channels closed", NULL, 0, TRUE);
7951 void ssh_sharing_downstream_connected(Ssh ssh, unsigned id,
7952 const char *peerinfo)
7955 logeventf(ssh, "Connection sharing downstream #%u connected from %s",
7958 logeventf(ssh, "Connection sharing downstream #%u connected", id);
7961 void ssh_sharing_downstream_disconnected(Ssh ssh, unsigned id)
7963 logeventf(ssh, "Connection sharing downstream #%u disconnected", id);
7964 ssh_check_termination(ssh);
7967 void ssh_sharing_logf(Ssh ssh, unsigned id, const char *logfmt, ...)
7972 va_start(ap, logfmt);
7973 buf = dupvprintf(logfmt, ap);
7976 logeventf(ssh, "Connection sharing downstream #%u: %s", id, buf);
7978 logeventf(ssh, "Connection sharing: %s", buf);
7982 static void ssh_channel_destroy(struct ssh_channel *c)
7987 case CHAN_MAINSESSION:
7988 ssh->mainchan = NULL;
7989 update_specials_menu(ssh->frontend);
7992 if (c->u.x11.xconn != NULL)
7993 x11_close(c->u.x11.xconn);
7994 logevent("Forwarded X11 connection terminated");
7997 sfree(c->u.a.message);
8000 if (c->u.pfd.pf != NULL)
8001 pfd_close(c->u.pfd.pf);
8002 logevent("Forwarded port closed");
8006 del234(ssh->channels, c);
8007 if (ssh->version == 2) {
8008 bufchain_clear(&c->v.v2.outbuffer);
8009 assert(c->v.v2.chanreq_head == NULL);
8014 * If that was the last channel left open, we might need to
8017 ssh_check_termination(ssh);
8020 static void ssh2_channel_check_close(struct ssh_channel *c)
8023 struct Packet *pktout;
8027 * If we've sent out our own CHANNEL_OPEN but not yet seen
8028 * either OPEN_CONFIRMATION or OPEN_FAILURE in response, then
8029 * it's too early to be sending close messages of any kind.
8034 if ((!((CLOSES_SENT_EOF | CLOSES_RCVD_EOF) & ~c->closes) ||
8035 c->type == CHAN_ZOMBIE) &&
8036 !c->v.v2.chanreq_head &&
8037 !(c->closes & CLOSES_SENT_CLOSE)) {
8039 * We have both sent and received EOF (or the channel is a
8040 * zombie), and we have no outstanding channel requests, which
8041 * means the channel is in final wind-up. But we haven't sent
8042 * CLOSE, so let's do so now.
8044 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE);
8045 ssh2_pkt_adduint32(pktout, c->remoteid);
8046 ssh2_pkt_send(ssh, pktout);
8047 c->closes |= CLOSES_SENT_EOF | CLOSES_SENT_CLOSE;
8050 if (!((CLOSES_SENT_CLOSE | CLOSES_RCVD_CLOSE) & ~c->closes)) {
8051 assert(c->v.v2.chanreq_head == NULL);
8053 * We have both sent and received CLOSE, which means we're
8054 * completely done with the channel.
8056 ssh_channel_destroy(c);
8060 static void ssh2_channel_got_eof(struct ssh_channel *c)
8062 if (c->closes & CLOSES_RCVD_EOF)
8063 return; /* already seen EOF */
8064 c->closes |= CLOSES_RCVD_EOF;
8066 if (c->type == CHAN_X11) {
8067 x11_send_eof(c->u.x11.xconn);
8068 } else if (c->type == CHAN_AGENT) {
8069 if (c->u.a.outstanding_requests == 0) {
8070 /* Manufacture an outgoing EOF in response to the incoming one. */
8071 sshfwd_write_eof(c);
8073 } else if (c->type == CHAN_SOCKDATA) {
8074 pfd_send_eof(c->u.pfd.pf);
8075 } else if (c->type == CHAN_MAINSESSION) {
8078 if (!ssh->sent_console_eof &&
8079 (from_backend_eof(ssh->frontend) || ssh->got_pty)) {
8081 * Either from_backend_eof told us that the front end
8082 * wants us to close the outgoing side of the connection
8083 * as soon as we see EOF from the far end, or else we've
8084 * unilaterally decided to do that because we've allocated
8085 * a remote pty and hence EOF isn't a particularly
8086 * meaningful concept.
8088 sshfwd_write_eof(c);
8090 ssh->sent_console_eof = TRUE;
8093 ssh2_channel_check_close(c);
8096 static void ssh2_msg_channel_eof(Ssh ssh, struct Packet *pktin)
8098 struct ssh_channel *c;
8100 c = ssh2_channel_msg(ssh, pktin);
8103 if (c->type == CHAN_SHARING) {
8104 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
8105 pktin->body, pktin->length);
8108 ssh2_channel_got_eof(c);
8111 static void ssh2_msg_channel_close(Ssh ssh, struct Packet *pktin)
8113 struct ssh_channel *c;
8115 c = ssh2_channel_msg(ssh, pktin);
8118 if (c->type == CHAN_SHARING) {
8119 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
8120 pktin->body, pktin->length);
8125 * When we receive CLOSE on a channel, we assume it comes with an
8126 * implied EOF if we haven't seen EOF yet.
8128 ssh2_channel_got_eof(c);
8130 if (!(ssh->remote_bugs & BUG_SENDS_LATE_REQUEST_REPLY)) {
8132 * It also means we stop expecting to see replies to any
8133 * outstanding channel requests, so clean those up too.
8134 * (ssh_chanreq_init will enforce by assertion that we don't
8135 * subsequently put anything back on this list.)
8137 while (c->v.v2.chanreq_head) {
8138 struct outstanding_channel_request *ocr = c->v.v2.chanreq_head;
8139 ocr->handler(c, NULL, ocr->ctx);
8140 c->v.v2.chanreq_head = ocr->next;
8146 * And we also send an outgoing EOF, if we haven't already, on the
8147 * assumption that CLOSE is a pretty forceful announcement that
8148 * the remote side is doing away with the entire channel. (If it
8149 * had wanted to send us EOF and continue receiving data from us,
8150 * it would have just sent CHANNEL_EOF.)
8152 if (!(c->closes & CLOSES_SENT_EOF)) {
8154 * Make sure we don't read any more from whatever our local
8155 * data source is for this channel.
8158 case CHAN_MAINSESSION:
8159 ssh->send_ok = 0; /* stop trying to read from stdin */
8162 x11_override_throttle(c->u.x11.xconn, 1);
8165 pfd_override_throttle(c->u.pfd.pf, 1);
8170 * Abandon any buffered data we still wanted to send to this
8171 * channel. Receiving a CHANNEL_CLOSE is an indication that
8172 * the server really wants to get on and _destroy_ this
8173 * channel, and it isn't going to send us any further
8174 * WINDOW_ADJUSTs to permit us to send pending stuff.
8176 bufchain_clear(&c->v.v2.outbuffer);
8179 * Send outgoing EOF.
8181 sshfwd_write_eof(c);
8185 * Now process the actual close.
8187 if (!(c->closes & CLOSES_RCVD_CLOSE)) {
8188 c->closes |= CLOSES_RCVD_CLOSE;
8189 ssh2_channel_check_close(c);
8193 static void ssh2_msg_channel_open_confirmation(Ssh ssh, struct Packet *pktin)
8195 struct ssh_channel *c;
8197 c = ssh2_channel_msg(ssh, pktin);
8200 if (c->type == CHAN_SHARING) {
8201 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
8202 pktin->body, pktin->length);
8205 assert(c->halfopen); /* ssh2_channel_msg will have enforced this */
8206 c->remoteid = ssh_pkt_getuint32(pktin);
8207 c->halfopen = FALSE;
8208 c->v.v2.remwindow = ssh_pkt_getuint32(pktin);
8209 c->v.v2.remmaxpkt = ssh_pkt_getuint32(pktin);
8211 if (c->type == CHAN_SOCKDATA_DORMANT) {
8212 c->type = CHAN_SOCKDATA;
8214 pfd_confirm(c->u.pfd.pf);
8215 } else if (c->type == CHAN_ZOMBIE) {
8217 * This case can occur if a local socket error occurred
8218 * between us sending out CHANNEL_OPEN and receiving
8219 * OPEN_CONFIRMATION. In this case, all we can do is
8220 * immediately initiate close proceedings now that we know the
8221 * server's id to put in the close message.
8223 ssh2_channel_check_close(c);
8226 * We never expect to receive OPEN_CONFIRMATION for any
8227 * *other* channel type (since only local-to-remote port
8228 * forwardings cause us to send CHANNEL_OPEN after the main
8229 * channel is live - all other auxiliary channel types are
8230 * initiated from the server end). It's safe to enforce this
8231 * by assertion rather than by ssh_disconnect, because the
8232 * real point is that we never constructed a half-open channel
8233 * structure in the first place with any type other than the
8236 assert(!"Funny channel type in ssh2_msg_channel_open_confirmation");
8240 ssh_channel_try_eof(c); /* in case we had a pending EOF */
8243 static void ssh2_msg_channel_open_failure(Ssh ssh, struct Packet *pktin)
8245 static const char *const reasons[] = {
8246 "<unknown reason code>",
8247 "Administratively prohibited",
8249 "Unknown channel type",
8250 "Resource shortage",
8252 unsigned reason_code;
8253 char *reason_string;
8255 struct ssh_channel *c;
8257 c = ssh2_channel_msg(ssh, pktin);
8260 if (c->type == CHAN_SHARING) {
8261 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
8262 pktin->body, pktin->length);
8265 assert(c->halfopen); /* ssh2_channel_msg will have enforced this */
8267 if (c->type == CHAN_SOCKDATA_DORMANT) {
8268 reason_code = ssh_pkt_getuint32(pktin);
8269 if (reason_code >= lenof(reasons))
8270 reason_code = 0; /* ensure reasons[reason_code] in range */
8271 ssh_pkt_getstring(pktin, &reason_string, &reason_length);
8272 logeventf(ssh, "Forwarded connection refused by server: %s [%.*s]",
8273 reasons[reason_code], reason_length,
8274 NULLTOEMPTY(reason_string));
8276 pfd_close(c->u.pfd.pf);
8277 } else if (c->type == CHAN_ZOMBIE) {
8279 * This case can occur if a local socket error occurred
8280 * between us sending out CHANNEL_OPEN and receiving
8281 * OPEN_FAILURE. In this case, we need do nothing except allow
8282 * the code below to throw the half-open channel away.
8286 * We never expect to receive OPEN_FAILURE for any *other*
8287 * channel type (since only local-to-remote port forwardings
8288 * cause us to send CHANNEL_OPEN after the main channel is
8289 * live - all other auxiliary channel types are initiated from
8290 * the server end). It's safe to enforce this by assertion
8291 * rather than by ssh_disconnect, because the real point is
8292 * that we never constructed a half-open channel structure in
8293 * the first place with any type other than the above.
8295 assert(!"Funny channel type in ssh2_msg_channel_open_failure");
8298 del234(ssh->channels, c);
8302 static void ssh2_msg_channel_request(Ssh ssh, struct Packet *pktin)
8305 int typelen, want_reply;
8306 int reply = SSH2_MSG_CHANNEL_FAILURE; /* default */
8307 struct ssh_channel *c;
8308 struct Packet *pktout;
8310 c = ssh2_channel_msg(ssh, pktin);
8313 if (c->type == CHAN_SHARING) {
8314 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
8315 pktin->body, pktin->length);
8318 ssh_pkt_getstring(pktin, &type, &typelen);
8319 want_reply = ssh2_pkt_getbool(pktin);
8321 if (c->closes & CLOSES_SENT_CLOSE) {
8323 * We don't reply to channel requests after we've sent
8324 * CHANNEL_CLOSE for the channel, because our reply might
8325 * cross in the network with the other side's CHANNEL_CLOSE
8326 * and arrive after they have wound the channel up completely.
8332 * Having got the channel number, we now look at
8333 * the request type string to see if it's something
8336 if (c == ssh->mainchan) {
8338 * We recognise "exit-status" and "exit-signal" on
8339 * the primary channel.
8341 if (typelen == 11 &&
8342 !memcmp(type, "exit-status", 11)) {
8344 ssh->exitcode = ssh_pkt_getuint32(pktin);
8345 logeventf(ssh, "Server sent command exit status %d",
8347 reply = SSH2_MSG_CHANNEL_SUCCESS;
8349 } else if (typelen == 11 &&
8350 !memcmp(type, "exit-signal", 11)) {
8352 int is_plausible = TRUE, is_int = FALSE;
8353 char *fmt_sig = NULL, *fmt_msg = NULL;
8355 int msglen = 0, core = FALSE;
8356 /* ICK: older versions of OpenSSH (e.g. 3.4p1)
8357 * provide an `int' for the signal, despite its
8358 * having been a `string' in the drafts of RFC 4254 since at
8359 * least 2001. (Fixed in session.c 1.147.) Try to
8360 * infer which we can safely parse it as. */
8362 unsigned char *p = pktin->body +
8364 long len = pktin->length - pktin->savedpos;
8365 unsigned long num = GET_32BIT(p); /* what is it? */
8366 /* If it's 0, it hardly matters; assume string */
8370 int maybe_int = FALSE, maybe_str = FALSE;
8371 #define CHECK_HYPOTHESIS(offset, result) \
8374 int q = toint(offset); \
8375 if (q >= 0 && q+4 <= len) { \
8376 q = toint(q + 4 + GET_32BIT(p+q)); \
8377 if (q >= 0 && q+4 <= len && \
8378 ((q = toint(q + 4 + GET_32BIT(p+q))) != 0) && \
8383 CHECK_HYPOTHESIS(4+1, maybe_int);
8384 CHECK_HYPOTHESIS(4+num+1, maybe_str);
8385 #undef CHECK_HYPOTHESIS
8386 if (maybe_int && !maybe_str)
8388 else if (!maybe_int && maybe_str)
8391 /* Crikey. Either or neither. Panic. */
8392 is_plausible = FALSE;
8395 ssh->exitcode = 128; /* means `unknown signal' */
8398 /* Old non-standard OpenSSH. */
8399 int signum = ssh_pkt_getuint32(pktin);
8400 fmt_sig = dupprintf(" %d", signum);
8401 ssh->exitcode = 128 + signum;
8403 /* As per RFC 4254. */
8406 ssh_pkt_getstring(pktin, &sig, &siglen);
8407 /* Signal name isn't supposed to be blank, but
8408 * let's cope gracefully if it is. */
8410 fmt_sig = dupprintf(" \"%.*s\"",
8415 * Really hideous method of translating the
8416 * signal description back into a locally
8417 * meaningful number.
8422 #define TRANSLATE_SIGNAL(s) \
8423 else if (siglen == lenof(#s)-1 && !memcmp(sig, #s, siglen)) \
8424 ssh->exitcode = 128 + SIG ## s
8426 TRANSLATE_SIGNAL(ABRT);
8429 TRANSLATE_SIGNAL(ALRM);
8432 TRANSLATE_SIGNAL(FPE);
8435 TRANSLATE_SIGNAL(HUP);
8438 TRANSLATE_SIGNAL(ILL);
8441 TRANSLATE_SIGNAL(INT);
8444 TRANSLATE_SIGNAL(KILL);
8447 TRANSLATE_SIGNAL(PIPE);
8450 TRANSLATE_SIGNAL(QUIT);
8453 TRANSLATE_SIGNAL(SEGV);
8456 TRANSLATE_SIGNAL(TERM);
8459 TRANSLATE_SIGNAL(USR1);
8462 TRANSLATE_SIGNAL(USR2);
8464 #undef TRANSLATE_SIGNAL
8466 ssh->exitcode = 128;
8468 core = ssh2_pkt_getbool(pktin);
8469 ssh_pkt_getstring(pktin, &msg, &msglen);
8471 fmt_msg = dupprintf(" (\"%.*s\")", msglen, msg);
8473 /* ignore lang tag */
8474 } /* else don't attempt to parse */
8475 logeventf(ssh, "Server exited on signal%s%s%s",
8476 fmt_sig ? fmt_sig : "",
8477 core ? " (core dumped)" : "",
8478 fmt_msg ? fmt_msg : "");
8481 reply = SSH2_MSG_CHANNEL_SUCCESS;
8486 * This is a channel request we don't know
8487 * about, so we now either ignore the request
8488 * or respond with CHANNEL_FAILURE, depending
8491 reply = SSH2_MSG_CHANNEL_FAILURE;
8494 pktout = ssh2_pkt_init(reply);
8495 ssh2_pkt_adduint32(pktout, c->remoteid);
8496 ssh2_pkt_send(ssh, pktout);
8500 static void ssh2_msg_global_request(Ssh ssh, struct Packet *pktin)
8503 int typelen, want_reply;
8504 struct Packet *pktout;
8506 ssh_pkt_getstring(pktin, &type, &typelen);
8507 want_reply = ssh2_pkt_getbool(pktin);
8510 * We currently don't support any global requests
8511 * at all, so we either ignore the request or
8512 * respond with REQUEST_FAILURE, depending on
8516 pktout = ssh2_pkt_init(SSH2_MSG_REQUEST_FAILURE);
8517 ssh2_pkt_send(ssh, pktout);
8521 struct X11FakeAuth *ssh_sharing_add_x11_display(Ssh ssh, int authtype,
8525 struct X11FakeAuth *auth;
8528 * Make up a new set of fake X11 auth data, and add it to the tree
8529 * of currently valid ones with an indication of the sharing
8530 * context that it's relevant to.
8532 auth = x11_invent_fake_auth(ssh->x11authtree, authtype);
8533 auth->share_cs = share_cs;
8534 auth->share_chan = share_chan;
8539 void ssh_sharing_remove_x11_display(Ssh ssh, struct X11FakeAuth *auth)
8541 del234(ssh->x11authtree, auth);
8542 x11_free_fake_auth(auth);
8545 static void ssh2_msg_channel_open(Ssh ssh, struct Packet *pktin)
8552 const char *error = NULL;
8553 struct ssh_channel *c;
8554 unsigned remid, winsize, pktsize;
8555 unsigned our_winsize_override = 0;
8556 struct Packet *pktout;
8558 ssh_pkt_getstring(pktin, &type, &typelen);
8559 c = snew(struct ssh_channel);
8562 remid = ssh_pkt_getuint32(pktin);
8563 winsize = ssh_pkt_getuint32(pktin);
8564 pktsize = ssh_pkt_getuint32(pktin);
8566 if (typelen == 3 && !memcmp(type, "x11", 3)) {
8569 ssh_pkt_getstring(pktin, &peeraddr, &peeraddrlen);
8570 addrstr = dupprintf("%.*s", peeraddrlen, NULLTOEMPTY(peeraddr));
8571 peerport = ssh_pkt_getuint32(pktin);
8573 logeventf(ssh, "Received X11 connect request from %s:%d",
8576 if (!ssh->X11_fwd_enabled && !ssh->connshare)
8577 error = "X11 forwarding is not enabled";
8579 c->u.x11.xconn = x11_init(ssh->x11authtree, c,
8582 c->u.x11.initial = TRUE;
8585 * If we are a connection-sharing upstream, then we should
8586 * initially present a very small window, adequate to take
8587 * the X11 initial authorisation packet but not much more.
8588 * Downstream will then present us a larger window (by
8589 * fiat of the connection-sharing protocol) and we can
8590 * guarantee to send a positive-valued WINDOW_ADJUST.
8593 our_winsize_override = 128;
8595 logevent("Opened X11 forward channel");
8599 } else if (typelen == 15 &&
8600 !memcmp(type, "forwarded-tcpip", 15)) {
8601 struct ssh_rportfwd pf, *realpf;
8604 ssh_pkt_getstring(pktin, &shost, &shostlen);/* skip address */
8605 pf.shost = dupprintf("%.*s", shostlen, NULLTOEMPTY(shost));
8606 pf.sport = ssh_pkt_getuint32(pktin);
8607 ssh_pkt_getstring(pktin, &peeraddr, &peeraddrlen);
8608 peerport = ssh_pkt_getuint32(pktin);
8609 realpf = find234(ssh->rportfwds, &pf, NULL);
8610 logeventf(ssh, "Received remote port %s:%d open request "
8611 "from %.*s:%d", pf.shost, pf.sport,
8612 peeraddrlen, NULLTOEMPTY(peeraddr), peerport);
8615 if (realpf == NULL) {
8616 error = "Remote port is not recognised";
8620 if (realpf->share_ctx) {
8622 * This port forwarding is on behalf of a
8623 * connection-sharing downstream, so abandon our own
8624 * channel-open procedure and just pass the message on
8627 share_got_pkt_from_server(realpf->share_ctx, pktin->type,
8628 pktin->body, pktin->length);
8633 err = pfd_connect(&c->u.pfd.pf, realpf->dhost, realpf->dport,
8634 c, ssh->conf, realpf->pfrec->addressfamily);
8635 logeventf(ssh, "Attempting to forward remote port to "
8636 "%s:%d", realpf->dhost, realpf->dport);
8638 logeventf(ssh, "Port open failed: %s", err);
8640 error = "Port open failed";
8642 logevent("Forwarded port opened successfully");
8643 c->type = CHAN_SOCKDATA;
8646 } else if (typelen == 22 &&
8647 !memcmp(type, "auth-agent@openssh.com", 22)) {
8648 if (!ssh->agentfwd_enabled)
8649 error = "Agent forwarding is not enabled";
8651 c->type = CHAN_AGENT; /* identify channel type */
8652 c->u.a.lensofar = 0;
8653 c->u.a.message = NULL;
8654 c->u.a.outstanding_requests = 0;
8657 error = "Unsupported channel type requested";
8660 c->remoteid = remid;
8661 c->halfopen = FALSE;
8663 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_FAILURE);
8664 ssh2_pkt_adduint32(pktout, c->remoteid);
8665 ssh2_pkt_adduint32(pktout, SSH2_OPEN_CONNECT_FAILED);
8666 ssh2_pkt_addstring(pktout, error);
8667 ssh2_pkt_addstring(pktout, "en"); /* language tag */
8668 ssh2_pkt_send(ssh, pktout);
8669 logeventf(ssh, "Rejected channel open: %s", error);
8672 ssh2_channel_init(c);
8673 c->v.v2.remwindow = winsize;
8674 c->v.v2.remmaxpkt = pktsize;
8675 if (our_winsize_override) {
8676 c->v.v2.locwindow = c->v.v2.locmaxwin = c->v.v2.remlocwin =
8677 our_winsize_override;
8679 add234(ssh->channels, c);
8680 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
8681 ssh2_pkt_adduint32(pktout, c->remoteid);
8682 ssh2_pkt_adduint32(pktout, c->localid);
8683 ssh2_pkt_adduint32(pktout, c->v.v2.locwindow);
8684 ssh2_pkt_adduint32(pktout, OUR_V2_MAXPKT); /* our max pkt size */
8685 ssh2_pkt_send(ssh, pktout);
8689 void sshfwd_x11_sharing_handover(struct ssh_channel *c,
8690 void *share_cs, void *share_chan,
8691 const char *peer_addr, int peer_port,
8692 int endian, int protomajor, int protominor,
8693 const void *initial_data, int initial_len)
8696 * This function is called when we've just discovered that an X
8697 * forwarding channel on which we'd been handling the initial auth
8698 * ourselves turns out to be destined for a connection-sharing
8699 * downstream. So we turn the channel into a CHAN_SHARING, meaning
8700 * that we completely stop tracking windows and buffering data and
8701 * just pass more or less unmodified SSH messages back and forth.
8703 c->type = CHAN_SHARING;
8704 c->u.sharing.ctx = share_cs;
8705 share_setup_x11_channel(share_cs, share_chan,
8706 c->localid, c->remoteid, c->v.v2.remwindow,
8707 c->v.v2.remmaxpkt, c->v.v2.locwindow,
8708 peer_addr, peer_port, endian,
8709 protomajor, protominor,
8710 initial_data, initial_len);
8713 void sshfwd_x11_is_local(struct ssh_channel *c)
8716 * This function is called when we've just discovered that an X
8717 * forwarding channel is _not_ destined for a connection-sharing
8718 * downstream but we're going to handle it ourselves. We stop
8719 * presenting a cautiously small window and go into ordinary data
8722 c->u.x11.initial = FALSE;
8723 ssh2_set_window(c, ssh_is_simple(c->ssh) ? OUR_V2_BIGWIN : OUR_V2_WINSIZE);
8727 * Buffer banner messages for later display at some convenient point,
8728 * if we're going to display them.
8730 static void ssh2_msg_userauth_banner(Ssh ssh, struct Packet *pktin)
8732 /* Arbitrary limit to prevent unbounded inflation of buffer */
8733 if (conf_get_int(ssh->conf, CONF_ssh_show_banner) &&
8734 bufchain_size(&ssh->banner) <= 131072) {
8735 char *banner = NULL;
8737 ssh_pkt_getstring(pktin, &banner, &size);
8739 bufchain_add(&ssh->banner, banner, size);
8743 /* Helper function to deal with sending tty modes for "pty-req" */
8744 static void ssh2_send_ttymode(void *data, char *mode, char *val)
8746 struct Packet *pktout = (struct Packet *)data;
8748 unsigned int arg = 0;
8749 while (strcmp(mode, ssh_ttymodes[i].mode) != 0) i++;
8750 if (i == lenof(ssh_ttymodes)) return;
8751 switch (ssh_ttymodes[i].type) {
8753 arg = ssh_tty_parse_specchar(val);
8756 arg = ssh_tty_parse_boolean(val);
8759 ssh2_pkt_addbyte(pktout, ssh_ttymodes[i].opcode);
8760 ssh2_pkt_adduint32(pktout, arg);
8763 static void ssh2_setup_x11(struct ssh_channel *c, struct Packet *pktin,
8766 struct ssh2_setup_x11_state {
8770 struct Packet *pktout;
8771 crStateP(ssh2_setup_x11_state, ctx);
8775 logevent("Requesting X11 forwarding");
8776 pktout = ssh2_chanreq_init(ssh->mainchan, "x11-req",
8778 ssh2_pkt_addbool(pktout, 0); /* many connections */
8779 ssh2_pkt_addstring(pktout, ssh->x11auth->protoname);
8780 ssh2_pkt_addstring(pktout, ssh->x11auth->datastring);
8781 ssh2_pkt_adduint32(pktout, ssh->x11disp->screennum);
8782 ssh2_pkt_send(ssh, pktout);
8784 /* Wait to be called back with either a response packet, or NULL
8785 * meaning clean up and free our data */
8789 if (pktin->type == SSH2_MSG_CHANNEL_SUCCESS) {
8790 logevent("X11 forwarding enabled");
8791 ssh->X11_fwd_enabled = TRUE;
8793 logevent("X11 forwarding refused");
8799 static void ssh2_setup_agent(struct ssh_channel *c, struct Packet *pktin,
8802 struct ssh2_setup_agent_state {
8806 struct Packet *pktout;
8807 crStateP(ssh2_setup_agent_state, ctx);
8811 logevent("Requesting OpenSSH-style agent forwarding");
8812 pktout = ssh2_chanreq_init(ssh->mainchan, "auth-agent-req@openssh.com",
8813 ssh2_setup_agent, s);
8814 ssh2_pkt_send(ssh, pktout);
8816 /* Wait to be called back with either a response packet, or NULL
8817 * meaning clean up and free our data */
8821 if (pktin->type == SSH2_MSG_CHANNEL_SUCCESS) {
8822 logevent("Agent forwarding enabled");
8823 ssh->agentfwd_enabled = TRUE;
8825 logevent("Agent forwarding refused");
8831 static void ssh2_setup_pty(struct ssh_channel *c, struct Packet *pktin,
8834 struct ssh2_setup_pty_state {
8838 struct Packet *pktout;
8839 crStateP(ssh2_setup_pty_state, ctx);
8843 /* Unpick the terminal-speed string. */
8844 /* XXX perhaps we should allow no speeds to be sent. */
8845 ssh->ospeed = 38400; ssh->ispeed = 38400; /* last-resort defaults */
8846 sscanf(conf_get_str(ssh->conf, CONF_termspeed), "%d,%d", &ssh->ospeed, &ssh->ispeed);
8847 /* Build the pty request. */
8848 pktout = ssh2_chanreq_init(ssh->mainchan, "pty-req",
8850 ssh2_pkt_addstring(pktout, conf_get_str(ssh->conf, CONF_termtype));
8851 ssh2_pkt_adduint32(pktout, ssh->term_width);
8852 ssh2_pkt_adduint32(pktout, ssh->term_height);
8853 ssh2_pkt_adduint32(pktout, 0); /* pixel width */
8854 ssh2_pkt_adduint32(pktout, 0); /* pixel height */
8855 ssh2_pkt_addstring_start(pktout);
8856 parse_ttymodes(ssh, ssh2_send_ttymode, (void *)pktout);
8857 ssh2_pkt_addbyte(pktout, SSH2_TTY_OP_ISPEED);
8858 ssh2_pkt_adduint32(pktout, ssh->ispeed);
8859 ssh2_pkt_addbyte(pktout, SSH2_TTY_OP_OSPEED);
8860 ssh2_pkt_adduint32(pktout, ssh->ospeed);
8861 ssh2_pkt_addstring_data(pktout, "\0", 1); /* TTY_OP_END */
8862 ssh2_pkt_send(ssh, pktout);
8863 ssh->state = SSH_STATE_INTERMED;
8865 /* Wait to be called back with either a response packet, or NULL
8866 * meaning clean up and free our data */
8870 if (pktin->type == SSH2_MSG_CHANNEL_SUCCESS) {
8871 logeventf(ssh, "Allocated pty (ospeed %dbps, ispeed %dbps)",
8872 ssh->ospeed, ssh->ispeed);
8873 ssh->got_pty = TRUE;
8875 c_write_str(ssh, "Server refused to allocate pty\r\n");
8876 ssh->editing = ssh->echoing = 1;
8883 static void ssh2_setup_env(struct ssh_channel *c, struct Packet *pktin,
8886 struct ssh2_setup_env_state {
8888 int num_env, env_left, env_ok;
8891 struct Packet *pktout;
8892 crStateP(ssh2_setup_env_state, ctx);
8897 * Send environment variables.
8899 * Simplest thing here is to send all the requests at once, and
8900 * then wait for a whole bunch of successes or failures.
8906 for (val = conf_get_str_strs(ssh->conf, CONF_environmt, NULL, &key);
8908 val = conf_get_str_strs(ssh->conf, CONF_environmt, key, &key)) {
8909 pktout = ssh2_chanreq_init(ssh->mainchan, "env", ssh2_setup_env, s);
8910 ssh2_pkt_addstring(pktout, key);
8911 ssh2_pkt_addstring(pktout, val);
8912 ssh2_pkt_send(ssh, pktout);
8917 logeventf(ssh, "Sent %d environment variables", s->num_env);
8922 s->env_left = s->num_env;
8924 while (s->env_left > 0) {
8925 /* Wait to be called back with either a response packet,
8926 * or NULL meaning clean up and free our data */
8928 if (!pktin) goto out;
8929 if (pktin->type == SSH2_MSG_CHANNEL_SUCCESS)
8934 if (s->env_ok == s->num_env) {
8935 logevent("All environment variables successfully set");
8936 } else if (s->env_ok == 0) {
8937 logevent("All environment variables refused");
8938 c_write_str(ssh, "Server refused to set environment variables\r\n");
8940 logeventf(ssh, "%d environment variables refused",
8941 s->num_env - s->env_ok);
8942 c_write_str(ssh, "Server refused to set all environment variables\r\n");
8950 * Handle the SSH-2 userauth and connection layers.
8952 static void ssh2_msg_authconn(Ssh ssh, struct Packet *pktin)
8954 do_ssh2_authconn(ssh, NULL, 0, pktin);
8957 static void ssh2_response_authconn(struct ssh_channel *c, struct Packet *pktin,
8961 do_ssh2_authconn(c->ssh, NULL, 0, pktin);
8964 static void do_ssh2_authconn(Ssh ssh, const unsigned char *in, int inlen,
8965 struct Packet *pktin)
8967 struct do_ssh2_authconn_state {
8971 AUTH_TYPE_PUBLICKEY,
8972 AUTH_TYPE_PUBLICKEY_OFFER_LOUD,
8973 AUTH_TYPE_PUBLICKEY_OFFER_QUIET,
8975 AUTH_TYPE_GSSAPI, /* always QUIET */
8976 AUTH_TYPE_KEYBOARD_INTERACTIVE,
8977 AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET
8979 int done_service_req;
8980 int gotit, need_pw, can_pubkey, can_passwd, can_keyb_inter;
8981 int tried_pubkey_config, done_agent;
8986 int kbd_inter_refused;
8987 int we_are_in, userauth_success;
8988 prompts_t *cur_prompt;
8993 void *publickey_blob;
8994 int publickey_bloblen;
8995 int privatekey_available, privatekey_encrypted;
8996 char *publickey_algorithm;
8997 char *publickey_comment;
8998 unsigned char agent_request[5], *agent_response, *agentp;
8999 int agent_responselen;
9000 unsigned char *pkblob_in_agent;
9002 char *pkblob, *alg, *commentp;
9003 int pklen, alglen, commentlen;
9004 int siglen, retlen, len;
9005 char *q, *agentreq, *ret;
9007 struct Packet *pktout;
9010 struct ssh_gss_library *gsslib;
9011 Ssh_gss_ctx gss_ctx;
9012 Ssh_gss_buf gss_buf;
9013 Ssh_gss_buf gss_rcvtok, gss_sndtok;
9014 Ssh_gss_name gss_srv_name;
9015 Ssh_gss_stat gss_stat;
9018 crState(do_ssh2_authconn_state);
9022 /* Register as a handler for all the messages this coroutine handles. */
9023 ssh->packet_dispatch[SSH2_MSG_SERVICE_ACCEPT] = ssh2_msg_authconn;
9024 ssh->packet_dispatch[SSH2_MSG_USERAUTH_REQUEST] = ssh2_msg_authconn;
9025 ssh->packet_dispatch[SSH2_MSG_USERAUTH_FAILURE] = ssh2_msg_authconn;
9026 ssh->packet_dispatch[SSH2_MSG_USERAUTH_SUCCESS] = ssh2_msg_authconn;
9027 ssh->packet_dispatch[SSH2_MSG_USERAUTH_BANNER] = ssh2_msg_authconn;
9028 ssh->packet_dispatch[SSH2_MSG_USERAUTH_PK_OK] = ssh2_msg_authconn;
9029 /* ssh->packet_dispatch[SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ] = ssh2_msg_authconn; duplicate case value */
9030 /* ssh->packet_dispatch[SSH2_MSG_USERAUTH_INFO_REQUEST] = ssh2_msg_authconn; duplicate case value */
9031 ssh->packet_dispatch[SSH2_MSG_USERAUTH_INFO_RESPONSE] = ssh2_msg_authconn;
9032 ssh->packet_dispatch[SSH2_MSG_GLOBAL_REQUEST] = ssh2_msg_authconn;
9033 ssh->packet_dispatch[SSH2_MSG_REQUEST_SUCCESS] = ssh2_msg_authconn;
9034 ssh->packet_dispatch[SSH2_MSG_REQUEST_FAILURE] = ssh2_msg_authconn;
9035 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN] = ssh2_msg_authconn;
9036 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_CONFIRMATION] = ssh2_msg_authconn;
9037 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_FAILURE] = ssh2_msg_authconn;
9038 ssh->packet_dispatch[SSH2_MSG_CHANNEL_WINDOW_ADJUST] = ssh2_msg_authconn;
9039 ssh->packet_dispatch[SSH2_MSG_CHANNEL_DATA] = ssh2_msg_authconn;
9040 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EXTENDED_DATA] = ssh2_msg_authconn;
9041 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EOF] = ssh2_msg_authconn;
9042 ssh->packet_dispatch[SSH2_MSG_CHANNEL_CLOSE] = ssh2_msg_authconn;
9044 s->done_service_req = FALSE;
9045 s->we_are_in = s->userauth_success = FALSE;
9046 s->agent_response = NULL;
9048 s->tried_gssapi = FALSE;
9051 if (!ssh->bare_connection) {
9052 if (!conf_get_int(ssh->conf, CONF_ssh_no_userauth)) {
9054 * Request userauth protocol, and await a response to it.
9056 s->pktout = ssh2_pkt_init(SSH2_MSG_SERVICE_REQUEST);
9057 ssh2_pkt_addstring(s->pktout, "ssh-userauth");
9058 ssh2_pkt_send(ssh, s->pktout);
9059 crWaitUntilV(pktin);
9060 if (pktin->type == SSH2_MSG_SERVICE_ACCEPT)
9061 s->done_service_req = TRUE;
9063 if (!s->done_service_req) {
9065 * Request connection protocol directly, without authentication.
9067 s->pktout = ssh2_pkt_init(SSH2_MSG_SERVICE_REQUEST);
9068 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9069 ssh2_pkt_send(ssh, s->pktout);
9070 crWaitUntilV(pktin);
9071 if (pktin->type == SSH2_MSG_SERVICE_ACCEPT) {
9072 s->we_are_in = TRUE; /* no auth required */
9074 bombout(("Server refused service request"));
9079 s->we_are_in = TRUE;
9082 /* Arrange to be able to deal with any BANNERs that come in.
9083 * (We do this now as packets may come in during the next bit.) */
9084 bufchain_init(&ssh->banner);
9085 ssh->packet_dispatch[SSH2_MSG_USERAUTH_BANNER] =
9086 ssh2_msg_userauth_banner;
9089 * Misc one-time setup for authentication.
9091 s->publickey_blob = NULL;
9092 if (!s->we_are_in) {
9095 * Load the public half of any configured public key file
9098 s->keyfile = conf_get_filename(ssh->conf, CONF_keyfile);
9099 if (!filename_is_null(s->keyfile)) {
9101 logeventf(ssh, "Reading key file \"%.150s\"",
9102 filename_to_str(s->keyfile));
9103 keytype = key_type(s->keyfile);
9104 if (keytype == SSH_KEYTYPE_SSH2 ||
9105 keytype == SSH_KEYTYPE_SSH2_PUBLIC_RFC4716 ||
9106 keytype == SSH_KEYTYPE_SSH2_PUBLIC_OPENSSH) {
9109 ssh2_userkey_loadpub(s->keyfile,
9110 &s->publickey_algorithm,
9111 &s->publickey_bloblen,
9112 &s->publickey_comment, &error);
9113 if (s->publickey_blob) {
9114 s->privatekey_available = (keytype == SSH_KEYTYPE_SSH2);
9115 if (!s->privatekey_available)
9116 logeventf(ssh, "Key file contains public key only");
9117 s->privatekey_encrypted =
9118 ssh2_userkey_encrypted(s->keyfile, NULL);
9121 logeventf(ssh, "Unable to load key (%s)",
9123 msgbuf = dupprintf("Unable to load key file "
9124 "\"%.150s\" (%s)\r\n",
9125 filename_to_str(s->keyfile),
9127 c_write_str(ssh, msgbuf);
9132 logeventf(ssh, "Unable to use this key file (%s)",
9133 key_type_to_str(keytype));
9134 msgbuf = dupprintf("Unable to use key file \"%.150s\""
9136 filename_to_str(s->keyfile),
9137 key_type_to_str(keytype));
9138 c_write_str(ssh, msgbuf);
9140 s->publickey_blob = NULL;
9145 * Find out about any keys Pageant has (but if there's a
9146 * public key configured, filter out all others).
9149 s->agent_response = NULL;
9150 s->pkblob_in_agent = NULL;
9151 if (conf_get_int(ssh->conf, CONF_tryagent) && agent_exists()) {
9155 logevent("Pageant is running. Requesting keys.");
9157 /* Request the keys held by the agent. */
9158 PUT_32BIT(s->agent_request, 1);
9159 s->agent_request[4] = SSH2_AGENTC_REQUEST_IDENTITIES;
9160 if (!agent_query(s->agent_request, 5, &r, &s->agent_responselen,
9161 ssh_agent_callback, ssh)) {
9165 bombout(("Unexpected data from server while"
9166 " waiting for agent response"));
9169 } while (pktin || inlen > 0);
9170 r = ssh->agent_response;
9171 s->agent_responselen = ssh->agent_response_len;
9173 s->agent_response = (unsigned char *) r;
9174 if (s->agent_response && s->agent_responselen >= 5 &&
9175 s->agent_response[4] == SSH2_AGENT_IDENTITIES_ANSWER) {
9178 p = s->agent_response + 5;
9179 s->nkeys = toint(GET_32BIT(p));
9182 * Vet the Pageant response to ensure that the key
9183 * count and blob lengths make sense.
9186 logeventf(ssh, "Pageant response contained a negative"
9187 " key count %d", s->nkeys);
9189 goto done_agent_query;
9191 unsigned char *q = p + 4;
9192 int lenleft = s->agent_responselen - 5 - 4;
9194 for (keyi = 0; keyi < s->nkeys; keyi++) {
9195 int bloblen, commentlen;
9197 logeventf(ssh, "Pageant response was truncated");
9199 goto done_agent_query;
9201 bloblen = toint(GET_32BIT(q));
9202 if (bloblen < 0 || bloblen > lenleft) {
9203 logeventf(ssh, "Pageant response was truncated");
9205 goto done_agent_query;
9207 lenleft -= 4 + bloblen;
9209 commentlen = toint(GET_32BIT(q));
9210 if (commentlen < 0 || commentlen > lenleft) {
9211 logeventf(ssh, "Pageant response was truncated");
9213 goto done_agent_query;
9215 lenleft -= 4 + commentlen;
9216 q += 4 + commentlen;
9221 logeventf(ssh, "Pageant has %d SSH-2 keys", s->nkeys);
9222 if (s->publickey_blob) {
9223 /* See if configured key is in agent. */
9224 for (keyi = 0; keyi < s->nkeys; keyi++) {
9225 s->pklen = toint(GET_32BIT(p));
9226 if (s->pklen == s->publickey_bloblen &&
9227 !memcmp(p+4, s->publickey_blob,
9228 s->publickey_bloblen)) {
9229 logeventf(ssh, "Pageant key #%d matches "
9230 "configured key file", keyi);
9232 s->pkblob_in_agent = p;
9236 p += toint(GET_32BIT(p)) + 4; /* comment */
9238 if (!s->pkblob_in_agent) {
9239 logevent("Configured key file not in Pageant");
9244 logevent("Failed to get reply from Pageant");
9252 * We repeat this whole loop, including the username prompt,
9253 * until we manage a successful authentication. If the user
9254 * types the wrong _password_, they can be sent back to the
9255 * beginning to try another username, if this is configured on.
9256 * (If they specify a username in the config, they are never
9257 * asked, even if they do give a wrong password.)
9259 * I think this best serves the needs of
9261 * - the people who have no configuration, no keys, and just
9262 * want to try repeated (username,password) pairs until they
9263 * type both correctly
9265 * - people who have keys and configuration but occasionally
9266 * need to fall back to passwords
9268 * - people with a key held in Pageant, who might not have
9269 * logged in to a particular machine before; so they want to
9270 * type a username, and then _either_ their key will be
9271 * accepted, _or_ they will type a password. If they mistype
9272 * the username they will want to be able to get back and
9275 s->got_username = FALSE;
9276 while (!s->we_are_in) {
9280 if (s->got_username && !conf_get_int(ssh->conf, CONF_change_username)) {
9282 * We got a username last time round this loop, and
9283 * with change_username turned off we don't try to get
9286 } else if ((ssh->username = get_remote_username(ssh->conf)) == NULL) {
9287 int ret; /* need not be kept over crReturn */
9288 s->cur_prompt = new_prompts(ssh->frontend);
9289 s->cur_prompt->to_server = TRUE;
9290 s->cur_prompt->name = dupstr("SSH login name");
9291 add_prompt(s->cur_prompt, dupstr("login as: "), TRUE);
9292 ret = get_userpass_input(s->cur_prompt, NULL, 0);
9295 crWaitUntilV(!pktin);
9296 ret = get_userpass_input(s->cur_prompt, in, inlen);
9301 * get_userpass_input() failed to get a username.
9304 free_prompts(s->cur_prompt);
9305 ssh_disconnect(ssh, "No username provided", NULL, 0, TRUE);
9308 ssh->username = dupstr(s->cur_prompt->prompts[0]->result);
9309 free_prompts(s->cur_prompt);
9312 if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
9313 stuff = dupprintf("Using username \"%s\".\r\n", ssh->username);
9314 c_write_str(ssh, stuff);
9318 s->got_username = TRUE;
9321 * Send an authentication request using method "none": (a)
9322 * just in case it succeeds, and (b) so that we know what
9323 * authentication methods we can usefully try next.
9325 ssh->pkt_actx = SSH2_PKTCTX_NOAUTH;
9327 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9328 ssh2_pkt_addstring(s->pktout, ssh->username);
9329 ssh2_pkt_addstring(s->pktout, "ssh-connection");/* service requested */
9330 ssh2_pkt_addstring(s->pktout, "none"); /* method */
9331 ssh2_pkt_send(ssh, s->pktout);
9332 s->type = AUTH_TYPE_NONE;
9334 s->we_are_in = FALSE;
9336 s->tried_pubkey_config = FALSE;
9337 s->kbd_inter_refused = FALSE;
9339 /* Reset agent request state. */
9340 s->done_agent = FALSE;
9341 if (s->agent_response) {
9342 if (s->pkblob_in_agent) {
9343 s->agentp = s->pkblob_in_agent;
9345 s->agentp = s->agent_response + 5 + 4;
9351 char *methods = NULL;
9355 * Wait for the result of the last authentication request.
9358 crWaitUntilV(pktin);
9360 * Now is a convenient point to spew any banner material
9361 * that we've accumulated. (This should ensure that when
9362 * we exit the auth loop, we haven't any left to deal
9366 int size = bufchain_size(&ssh->banner);
9368 * Don't show the banner if we're operating in
9369 * non-verbose non-interactive mode. (It's probably
9370 * a script, which means nobody will read the
9371 * banner _anyway_, and moreover the printing of
9372 * the banner will screw up processing on the
9373 * output of (say) plink.)
9375 if (size && (flags & (FLAG_VERBOSE | FLAG_INTERACTIVE))) {
9376 char *banner = snewn(size, char);
9377 bufchain_fetch(&ssh->banner, banner, size);
9378 c_write_untrusted(ssh, banner, size);
9381 bufchain_clear(&ssh->banner);
9383 if (pktin->type == SSH2_MSG_USERAUTH_SUCCESS) {
9384 logevent("Access granted");
9385 s->we_are_in = s->userauth_success = TRUE;
9389 if (pktin->type != SSH2_MSG_USERAUTH_FAILURE && s->type != AUTH_TYPE_GSSAPI) {
9390 bombout(("Strange packet received during authentication: "
9391 "type %d", pktin->type));
9398 * OK, we're now sitting on a USERAUTH_FAILURE message, so
9399 * we can look at the string in it and know what we can
9400 * helpfully try next.
9402 if (pktin->type == SSH2_MSG_USERAUTH_FAILURE) {
9403 ssh_pkt_getstring(pktin, &methods, &methlen);
9404 if (!ssh2_pkt_getbool(pktin)) {
9406 * We have received an unequivocal Access
9407 * Denied. This can translate to a variety of
9408 * messages, or no message at all.
9410 * For forms of authentication which are attempted
9411 * implicitly, by which I mean without printing
9412 * anything in the window indicating that we're
9413 * trying them, we should never print 'Access
9416 * If we do print a message saying that we're
9417 * attempting some kind of authentication, it's OK
9418 * to print a followup message saying it failed -
9419 * but the message may sometimes be more specific
9420 * than simply 'Access denied'.
9422 * Additionally, if we'd just tried password
9423 * authentication, we should break out of this
9424 * whole loop so as to go back to the username
9425 * prompt (iff we're configured to allow
9426 * username change attempts).
9428 if (s->type == AUTH_TYPE_NONE) {
9430 } else if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD ||
9431 s->type == AUTH_TYPE_PUBLICKEY_OFFER_QUIET) {
9432 if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD)
9433 c_write_str(ssh, "Server refused our key\r\n");
9434 logevent("Server refused our key");
9435 } else if (s->type == AUTH_TYPE_PUBLICKEY) {
9436 /* This _shouldn't_ happen except by a
9437 * protocol bug causing client and server to
9438 * disagree on what is a correct signature. */
9439 c_write_str(ssh, "Server refused public-key signature"
9440 " despite accepting key!\r\n");
9441 logevent("Server refused public-key signature"
9442 " despite accepting key!");
9443 } else if (s->type==AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET) {
9444 /* quiet, so no c_write */
9445 logevent("Server refused keyboard-interactive authentication");
9446 } else if (s->type==AUTH_TYPE_GSSAPI) {
9447 /* always quiet, so no c_write */
9448 /* also, the code down in the GSSAPI block has
9449 * already logged this in the Event Log */
9450 } else if (s->type == AUTH_TYPE_KEYBOARD_INTERACTIVE) {
9451 logevent("Keyboard-interactive authentication failed");
9452 c_write_str(ssh, "Access denied\r\n");
9454 assert(s->type == AUTH_TYPE_PASSWORD);
9455 logevent("Password authentication failed");
9456 c_write_str(ssh, "Access denied\r\n");
9458 if (conf_get_int(ssh->conf, CONF_change_username)) {
9459 /* XXX perhaps we should allow
9460 * keyboard-interactive to do this too? */
9461 s->we_are_in = FALSE;
9466 c_write_str(ssh, "Further authentication required\r\n");
9467 logevent("Further authentication required");
9471 in_commasep_string("publickey", methods, methlen);
9473 in_commasep_string("password", methods, methlen);
9474 s->can_keyb_inter = conf_get_int(ssh->conf, CONF_try_ki_auth) &&
9475 in_commasep_string("keyboard-interactive", methods, methlen);
9477 if (conf_get_int(ssh->conf, CONF_try_gssapi_auth) &&
9478 in_commasep_string("gssapi-with-mic", methods, methlen)) {
9479 /* Try loading the GSS libraries and see if we
9482 ssh->gsslibs = ssh_gss_setup(ssh->conf);
9483 s->can_gssapi = (ssh->gsslibs->nlibraries > 0);
9485 /* No point in even bothering to try to load the
9486 * GSS libraries, if the user configuration and
9487 * server aren't both prepared to attempt GSSAPI
9488 * auth in the first place. */
9489 s->can_gssapi = FALSE;
9494 ssh->pkt_actx = SSH2_PKTCTX_NOAUTH;
9496 if (s->can_pubkey && !s->done_agent && s->nkeys) {
9499 * Attempt public-key authentication using a key from Pageant.
9502 ssh->pkt_actx = SSH2_PKTCTX_PUBLICKEY;
9504 logeventf(ssh, "Trying Pageant key #%d", s->keyi);
9506 /* Unpack key from agent response */
9507 s->pklen = toint(GET_32BIT(s->agentp));
9509 s->pkblob = (char *)s->agentp;
9510 s->agentp += s->pklen;
9511 s->alglen = toint(GET_32BIT(s->pkblob));
9512 s->alg = s->pkblob + 4;
9513 s->commentlen = toint(GET_32BIT(s->agentp));
9515 s->commentp = (char *)s->agentp;
9516 s->agentp += s->commentlen;
9517 /* s->agentp now points at next key, if any */
9519 /* See if server will accept it */
9520 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9521 ssh2_pkt_addstring(s->pktout, ssh->username);
9522 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9523 /* service requested */
9524 ssh2_pkt_addstring(s->pktout, "publickey");
9526 ssh2_pkt_addbool(s->pktout, FALSE); /* no signature included */
9527 ssh2_pkt_addstring_start(s->pktout);
9528 ssh2_pkt_addstring_data(s->pktout, s->alg, s->alglen);
9529 ssh2_pkt_addstring_start(s->pktout);
9530 ssh2_pkt_addstring_data(s->pktout, s->pkblob, s->pklen);
9531 ssh2_pkt_send(ssh, s->pktout);
9532 s->type = AUTH_TYPE_PUBLICKEY_OFFER_QUIET;
9534 crWaitUntilV(pktin);
9535 if (pktin->type != SSH2_MSG_USERAUTH_PK_OK) {
9537 /* Offer of key refused. */
9544 if (flags & FLAG_VERBOSE) {
9545 c_write_str(ssh, "Authenticating with "
9547 c_write(ssh, s->commentp, s->commentlen);
9548 c_write_str(ssh, "\" from agent\r\n");
9552 * Server is willing to accept the key.
9553 * Construct a SIGN_REQUEST.
9555 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9556 ssh2_pkt_addstring(s->pktout, ssh->username);
9557 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9558 /* service requested */
9559 ssh2_pkt_addstring(s->pktout, "publickey");
9561 ssh2_pkt_addbool(s->pktout, TRUE); /* signature included */
9562 ssh2_pkt_addstring_start(s->pktout);
9563 ssh2_pkt_addstring_data(s->pktout, s->alg, s->alglen);
9564 ssh2_pkt_addstring_start(s->pktout);
9565 ssh2_pkt_addstring_data(s->pktout, s->pkblob, s->pklen);
9567 /* Ask agent for signature. */
9568 s->siglen = s->pktout->length - 5 + 4 +
9569 ssh->v2_session_id_len;
9570 if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
9572 s->len = 1; /* message type */
9573 s->len += 4 + s->pklen; /* key blob */
9574 s->len += 4 + s->siglen; /* data to sign */
9575 s->len += 4; /* flags */
9576 s->agentreq = snewn(4 + s->len, char);
9577 PUT_32BIT(s->agentreq, s->len);
9578 s->q = s->agentreq + 4;
9579 *s->q++ = SSH2_AGENTC_SIGN_REQUEST;
9580 PUT_32BIT(s->q, s->pklen);
9582 memcpy(s->q, s->pkblob, s->pklen);
9584 PUT_32BIT(s->q, s->siglen);
9586 /* Now the data to be signed... */
9587 if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
9588 PUT_32BIT(s->q, ssh->v2_session_id_len);
9591 memcpy(s->q, ssh->v2_session_id,
9592 ssh->v2_session_id_len);
9593 s->q += ssh->v2_session_id_len;
9594 memcpy(s->q, s->pktout->data + 5,
9595 s->pktout->length - 5);
9596 s->q += s->pktout->length - 5;
9597 /* And finally the (zero) flags word. */
9599 if (!agent_query(s->agentreq, s->len + 4,
9601 ssh_agent_callback, ssh)) {
9605 bombout(("Unexpected data from server"
9606 " while waiting for agent"
9610 } while (pktin || inlen > 0);
9611 vret = ssh->agent_response;
9612 s->retlen = ssh->agent_response_len;
9617 if (s->retlen >= 9 &&
9618 s->ret[4] == SSH2_AGENT_SIGN_RESPONSE &&
9619 GET_32BIT(s->ret + 5) <= (unsigned)(s->retlen-9)) {
9620 logevent("Sending Pageant's response");
9621 ssh2_add_sigblob(ssh, s->pktout,
9622 s->pkblob, s->pklen,
9624 GET_32BIT(s->ret + 5));
9625 ssh2_pkt_send(ssh, s->pktout);
9626 s->type = AUTH_TYPE_PUBLICKEY;
9628 /* FIXME: less drastic response */
9629 bombout(("Pageant failed to answer challenge"));
9635 /* Do we have any keys left to try? */
9636 if (s->pkblob_in_agent) {
9637 s->done_agent = TRUE;
9638 s->tried_pubkey_config = TRUE;
9641 if (s->keyi >= s->nkeys)
9642 s->done_agent = TRUE;
9645 } else if (s->can_pubkey && s->publickey_blob &&
9646 s->privatekey_available && !s->tried_pubkey_config) {
9648 struct ssh2_userkey *key; /* not live over crReturn */
9649 char *passphrase; /* not live over crReturn */
9651 ssh->pkt_actx = SSH2_PKTCTX_PUBLICKEY;
9653 s->tried_pubkey_config = TRUE;
9656 * Try the public key supplied in the configuration.
9658 * First, offer the public blob to see if the server is
9659 * willing to accept it.
9661 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9662 ssh2_pkt_addstring(s->pktout, ssh->username);
9663 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9664 /* service requested */
9665 ssh2_pkt_addstring(s->pktout, "publickey"); /* method */
9666 ssh2_pkt_addbool(s->pktout, FALSE);
9667 /* no signature included */
9668 ssh2_pkt_addstring(s->pktout, s->publickey_algorithm);
9669 ssh2_pkt_addstring_start(s->pktout);
9670 ssh2_pkt_addstring_data(s->pktout,
9671 (char *)s->publickey_blob,
9672 s->publickey_bloblen);
9673 ssh2_pkt_send(ssh, s->pktout);
9674 logevent("Offered public key");
9676 crWaitUntilV(pktin);
9677 if (pktin->type != SSH2_MSG_USERAUTH_PK_OK) {
9678 /* Key refused. Give up. */
9679 s->gotit = TRUE; /* reconsider message next loop */
9680 s->type = AUTH_TYPE_PUBLICKEY_OFFER_LOUD;
9681 continue; /* process this new message */
9683 logevent("Offer of public key accepted");
9686 * Actually attempt a serious authentication using
9689 if (flags & FLAG_VERBOSE) {
9690 c_write_str(ssh, "Authenticating with public key \"");
9691 c_write_str(ssh, s->publickey_comment);
9692 c_write_str(ssh, "\"\r\n");
9696 const char *error; /* not live over crReturn */
9697 if (s->privatekey_encrypted) {
9699 * Get a passphrase from the user.
9701 int ret; /* need not be kept over crReturn */
9702 s->cur_prompt = new_prompts(ssh->frontend);
9703 s->cur_prompt->to_server = FALSE;
9704 s->cur_prompt->name = dupstr("SSH key passphrase");
9705 add_prompt(s->cur_prompt,
9706 dupprintf("Passphrase for key \"%.100s\": ",
9707 s->publickey_comment),
9709 ret = get_userpass_input(s->cur_prompt, NULL, 0);
9712 crWaitUntilV(!pktin);
9713 ret = get_userpass_input(s->cur_prompt,
9718 /* Failed to get a passphrase. Terminate. */
9719 free_prompts(s->cur_prompt);
9720 ssh_disconnect(ssh, NULL,
9721 "Unable to authenticate",
9722 SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER,
9727 dupstr(s->cur_prompt->prompts[0]->result);
9728 free_prompts(s->cur_prompt);
9730 passphrase = NULL; /* no passphrase needed */
9734 * Try decrypting the key.
9736 s->keyfile = conf_get_filename(ssh->conf, CONF_keyfile);
9737 key = ssh2_load_userkey(s->keyfile, passphrase, &error);
9739 /* burn the evidence */
9740 smemclr(passphrase, strlen(passphrase));
9743 if (key == SSH2_WRONG_PASSPHRASE || key == NULL) {
9745 (key == SSH2_WRONG_PASSPHRASE)) {
9746 c_write_str(ssh, "Wrong passphrase\r\n");
9748 /* and loop again */
9750 c_write_str(ssh, "Unable to load private key (");
9751 c_write_str(ssh, error);
9752 c_write_str(ssh, ")\r\n");
9754 break; /* try something else */
9760 unsigned char *pkblob, *sigblob, *sigdata;
9761 int pkblob_len, sigblob_len, sigdata_len;
9765 * We have loaded the private key and the server
9766 * has announced that it's willing to accept it.
9767 * Hallelujah. Generate a signature and send it.
9769 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9770 ssh2_pkt_addstring(s->pktout, ssh->username);
9771 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9772 /* service requested */
9773 ssh2_pkt_addstring(s->pktout, "publickey");
9775 ssh2_pkt_addbool(s->pktout, TRUE);
9776 /* signature follows */
9777 ssh2_pkt_addstring(s->pktout, key->alg->name);
9778 pkblob = key->alg->public_blob(key->data,
9780 ssh2_pkt_addstring_start(s->pktout);
9781 ssh2_pkt_addstring_data(s->pktout, (char *)pkblob,
9785 * The data to be signed is:
9789 * followed by everything so far placed in the
9792 sigdata_len = s->pktout->length - 5 + 4 +
9793 ssh->v2_session_id_len;
9794 if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
9796 sigdata = snewn(sigdata_len, unsigned char);
9798 if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
9799 PUT_32BIT(sigdata+p, ssh->v2_session_id_len);
9802 memcpy(sigdata+p, ssh->v2_session_id,
9803 ssh->v2_session_id_len);
9804 p += ssh->v2_session_id_len;
9805 memcpy(sigdata+p, s->pktout->data + 5,
9806 s->pktout->length - 5);
9807 p += s->pktout->length - 5;
9808 assert(p == sigdata_len);
9809 sigblob = key->alg->sign(key->data, (char *)sigdata,
9810 sigdata_len, &sigblob_len);
9811 ssh2_add_sigblob(ssh, s->pktout, pkblob, pkblob_len,
9812 sigblob, sigblob_len);
9817 ssh2_pkt_send(ssh, s->pktout);
9818 logevent("Sent public key signature");
9819 s->type = AUTH_TYPE_PUBLICKEY;
9820 key->alg->freekey(key->data);
9821 sfree(key->comment);
9826 } else if (s->can_gssapi && !s->tried_gssapi) {
9828 /* GSSAPI Authentication */
9833 s->type = AUTH_TYPE_GSSAPI;
9834 s->tried_gssapi = TRUE;
9836 ssh->pkt_actx = SSH2_PKTCTX_GSSAPI;
9839 * Pick the highest GSS library on the preference
9845 for (i = 0; i < ngsslibs; i++) {
9846 int want_id = conf_get_int_int(ssh->conf,
9847 CONF_ssh_gsslist, i);
9848 for (j = 0; j < ssh->gsslibs->nlibraries; j++)
9849 if (ssh->gsslibs->libraries[j].id == want_id) {
9850 s->gsslib = &ssh->gsslibs->libraries[j];
9851 goto got_gsslib; /* double break */
9856 * We always expect to have found something in
9857 * the above loop: we only came here if there
9858 * was at least one viable GSS library, and the
9859 * preference list should always mention
9860 * everything and only change the order.
9865 if (s->gsslib->gsslogmsg)
9866 logevent(s->gsslib->gsslogmsg);
9868 /* Sending USERAUTH_REQUEST with "gssapi-with-mic" method */
9869 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9870 ssh2_pkt_addstring(s->pktout, ssh->username);
9871 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9872 ssh2_pkt_addstring(s->pktout, "gssapi-with-mic");
9873 logevent("Attempting GSSAPI authentication");
9875 /* add mechanism info */
9876 s->gsslib->indicate_mech(s->gsslib, &s->gss_buf);
9878 /* number of GSSAPI mechanisms */
9879 ssh2_pkt_adduint32(s->pktout,1);
9881 /* length of OID + 2 */
9882 ssh2_pkt_adduint32(s->pktout, s->gss_buf.length + 2);
9883 ssh2_pkt_addbyte(s->pktout, SSH2_GSS_OIDTYPE);
9886 ssh2_pkt_addbyte(s->pktout, (unsigned char) s->gss_buf.length);
9888 ssh_pkt_adddata(s->pktout, s->gss_buf.value,
9890 ssh2_pkt_send(ssh, s->pktout);
9891 crWaitUntilV(pktin);
9892 if (pktin->type != SSH2_MSG_USERAUTH_GSSAPI_RESPONSE) {
9893 logevent("GSSAPI authentication request refused");
9897 /* check returned packet ... */
9899 ssh_pkt_getstring(pktin, &data, &len);
9900 s->gss_rcvtok.value = data;
9901 s->gss_rcvtok.length = len;
9902 if (s->gss_rcvtok.length != s->gss_buf.length + 2 ||
9903 ((char *)s->gss_rcvtok.value)[0] != SSH2_GSS_OIDTYPE ||
9904 ((char *)s->gss_rcvtok.value)[1] != s->gss_buf.length ||
9905 memcmp((char *)s->gss_rcvtok.value + 2,
9906 s->gss_buf.value,s->gss_buf.length) ) {
9907 logevent("GSSAPI authentication - wrong response from server");
9911 /* now start running */
9912 s->gss_stat = s->gsslib->import_name(s->gsslib,
9915 if (s->gss_stat != SSH_GSS_OK) {
9916 if (s->gss_stat == SSH_GSS_BAD_HOST_NAME)
9917 logevent("GSSAPI import name failed - Bad service name");
9919 logevent("GSSAPI import name failed");
9923 /* fetch TGT into GSS engine */
9924 s->gss_stat = s->gsslib->acquire_cred(s->gsslib, &s->gss_ctx);
9926 if (s->gss_stat != SSH_GSS_OK) {
9927 logevent("GSSAPI authentication failed to get credentials");
9928 s->gsslib->release_name(s->gsslib, &s->gss_srv_name);
9932 /* initial tokens are empty */
9933 SSH_GSS_CLEAR_BUF(&s->gss_rcvtok);
9934 SSH_GSS_CLEAR_BUF(&s->gss_sndtok);
9936 /* now enter the loop */
9938 s->gss_stat = s->gsslib->init_sec_context
9942 conf_get_int(ssh->conf, CONF_gssapifwd),
9946 if (s->gss_stat!=SSH_GSS_S_COMPLETE &&
9947 s->gss_stat!=SSH_GSS_S_CONTINUE_NEEDED) {
9948 logevent("GSSAPI authentication initialisation failed");
9950 if (s->gsslib->display_status(s->gsslib, s->gss_ctx,
9951 &s->gss_buf) == SSH_GSS_OK) {
9952 logevent(s->gss_buf.value);
9953 sfree(s->gss_buf.value);
9958 logevent("GSSAPI authentication initialised");
9960 /* Client and server now exchange tokens until GSSAPI
9961 * no longer says CONTINUE_NEEDED */
9963 if (s->gss_sndtok.length != 0) {
9964 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
9965 ssh_pkt_addstring_start(s->pktout);
9966 ssh_pkt_addstring_data(s->pktout,s->gss_sndtok.value,s->gss_sndtok.length);
9967 ssh2_pkt_send(ssh, s->pktout);
9968 s->gsslib->free_tok(s->gsslib, &s->gss_sndtok);
9971 if (s->gss_stat == SSH_GSS_S_CONTINUE_NEEDED) {
9972 crWaitUntilV(pktin);
9973 if (pktin->type != SSH2_MSG_USERAUTH_GSSAPI_TOKEN) {
9974 logevent("GSSAPI authentication - bad server response");
9975 s->gss_stat = SSH_GSS_FAILURE;
9978 ssh_pkt_getstring(pktin, &data, &len);
9979 s->gss_rcvtok.value = data;
9980 s->gss_rcvtok.length = len;
9982 } while (s-> gss_stat == SSH_GSS_S_CONTINUE_NEEDED);
9984 if (s->gss_stat != SSH_GSS_OK) {
9985 s->gsslib->release_name(s->gsslib, &s->gss_srv_name);
9986 s->gsslib->release_cred(s->gsslib, &s->gss_ctx);
9989 logevent("GSSAPI authentication loop finished OK");
9991 /* Now send the MIC */
9993 s->pktout = ssh2_pkt_init(0);
9994 micoffset = s->pktout->length;
9995 ssh_pkt_addstring_start(s->pktout);
9996 ssh_pkt_addstring_data(s->pktout, (char *)ssh->v2_session_id, ssh->v2_session_id_len);
9997 ssh_pkt_addbyte(s->pktout, SSH2_MSG_USERAUTH_REQUEST);
9998 ssh_pkt_addstring(s->pktout, ssh->username);
9999 ssh_pkt_addstring(s->pktout, "ssh-connection");
10000 ssh_pkt_addstring(s->pktout, "gssapi-with-mic");
10002 s->gss_buf.value = (char *)s->pktout->data + micoffset;
10003 s->gss_buf.length = s->pktout->length - micoffset;
10005 s->gsslib->get_mic(s->gsslib, s->gss_ctx, &s->gss_buf, &mic);
10006 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_GSSAPI_MIC);
10007 ssh_pkt_addstring_start(s->pktout);
10008 ssh_pkt_addstring_data(s->pktout, mic.value, mic.length);
10009 ssh2_pkt_send(ssh, s->pktout);
10010 s->gsslib->free_mic(s->gsslib, &mic);
10014 s->gsslib->release_name(s->gsslib, &s->gss_srv_name);
10015 s->gsslib->release_cred(s->gsslib, &s->gss_ctx);
10018 } else if (s->can_keyb_inter && !s->kbd_inter_refused) {
10021 * Keyboard-interactive authentication.
10024 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
10026 ssh->pkt_actx = SSH2_PKTCTX_KBDINTER;
10028 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
10029 ssh2_pkt_addstring(s->pktout, ssh->username);
10030 ssh2_pkt_addstring(s->pktout, "ssh-connection");
10031 /* service requested */
10032 ssh2_pkt_addstring(s->pktout, "keyboard-interactive");
10034 ssh2_pkt_addstring(s->pktout, ""); /* lang */
10035 ssh2_pkt_addstring(s->pktout, ""); /* submethods */
10036 ssh2_pkt_send(ssh, s->pktout);
10038 logevent("Attempting keyboard-interactive authentication");
10040 crWaitUntilV(pktin);
10041 if (pktin->type != SSH2_MSG_USERAUTH_INFO_REQUEST) {
10042 /* Server is not willing to do keyboard-interactive
10043 * at all (or, bizarrely but legally, accepts the
10044 * user without actually issuing any prompts).
10045 * Give up on it entirely. */
10047 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET;
10048 s->kbd_inter_refused = TRUE; /* don't try it again */
10053 * Loop while the server continues to send INFO_REQUESTs.
10055 while (pktin->type == SSH2_MSG_USERAUTH_INFO_REQUEST) {
10057 char *name, *inst, *lang;
10058 int name_len, inst_len, lang_len;
10062 * We've got a fresh USERAUTH_INFO_REQUEST.
10063 * Get the preamble and start building a prompt.
10065 ssh_pkt_getstring(pktin, &name, &name_len);
10066 ssh_pkt_getstring(pktin, &inst, &inst_len);
10067 ssh_pkt_getstring(pktin, &lang, &lang_len);
10068 s->cur_prompt = new_prompts(ssh->frontend);
10069 s->cur_prompt->to_server = TRUE;
10072 * Get any prompt(s) from the packet.
10074 s->num_prompts = ssh_pkt_getuint32(pktin);
10075 for (i = 0; i < s->num_prompts; i++) {
10079 static char noprompt[] =
10080 "<server failed to send prompt>: ";
10082 ssh_pkt_getstring(pktin, &prompt, &prompt_len);
10083 echo = ssh2_pkt_getbool(pktin);
10086 prompt_len = lenof(noprompt)-1;
10088 add_prompt(s->cur_prompt,
10089 dupprintf("%.*s", prompt_len, prompt),
10094 /* FIXME: better prefix to distinguish from
10095 * local prompts? */
10096 s->cur_prompt->name =
10097 dupprintf("SSH server: %.*s", name_len, name);
10098 s->cur_prompt->name_reqd = TRUE;
10100 s->cur_prompt->name =
10101 dupstr("SSH server authentication");
10102 s->cur_prompt->name_reqd = FALSE;
10104 /* We add a prefix to try to make it clear that a prompt
10105 * has come from the server.
10106 * FIXME: ugly to print "Using..." in prompt _every_
10107 * time round. Can this be done more subtly? */
10108 /* Special case: for reasons best known to themselves,
10109 * some servers send k-i requests with no prompts and
10110 * nothing to display. Keep quiet in this case. */
10111 if (s->num_prompts || name_len || inst_len) {
10112 s->cur_prompt->instruction =
10113 dupprintf("Using keyboard-interactive authentication.%s%.*s",
10114 inst_len ? "\n" : "", inst_len, inst);
10115 s->cur_prompt->instr_reqd = TRUE;
10117 s->cur_prompt->instr_reqd = FALSE;
10121 * Display any instructions, and get the user's
10125 int ret; /* not live over crReturn */
10126 ret = get_userpass_input(s->cur_prompt, NULL, 0);
10129 crWaitUntilV(!pktin);
10130 ret = get_userpass_input(s->cur_prompt, in, inlen);
10135 * Failed to get responses. Terminate.
10137 free_prompts(s->cur_prompt);
10138 ssh_disconnect(ssh, NULL, "Unable to authenticate",
10139 SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER,
10146 * Send the response(s) to the server.
10148 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_INFO_RESPONSE);
10149 ssh2_pkt_adduint32(s->pktout, s->num_prompts);
10150 for (i=0; i < s->num_prompts; i++) {
10151 ssh2_pkt_addstring(s->pktout,
10152 s->cur_prompt->prompts[i]->result);
10154 ssh2_pkt_send_with_padding(ssh, s->pktout, 256);
10157 * Free the prompts structure from this iteration.
10158 * If there's another, a new one will be allocated
10159 * when we return to the top of this while loop.
10161 free_prompts(s->cur_prompt);
10164 * Get the next packet in case it's another
10167 crWaitUntilV(pktin);
10172 * We should have SUCCESS or FAILURE now.
10176 } else if (s->can_passwd) {
10179 * Plain old password authentication.
10181 int ret; /* not live over crReturn */
10182 int changereq_first_time; /* not live over crReturn */
10184 ssh->pkt_actx = SSH2_PKTCTX_PASSWORD;
10186 s->cur_prompt = new_prompts(ssh->frontend);
10187 s->cur_prompt->to_server = TRUE;
10188 s->cur_prompt->name = dupstr("SSH password");
10189 add_prompt(s->cur_prompt, dupprintf("%s@%s's password: ",
10194 ret = get_userpass_input(s->cur_prompt, NULL, 0);
10197 crWaitUntilV(!pktin);
10198 ret = get_userpass_input(s->cur_prompt, in, inlen);
10203 * Failed to get responses. Terminate.
10205 free_prompts(s->cur_prompt);
10206 ssh_disconnect(ssh, NULL, "Unable to authenticate",
10207 SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER,
10212 * Squirrel away the password. (We may need it later if
10213 * asked to change it.)
10215 s->password = dupstr(s->cur_prompt->prompts[0]->result);
10216 free_prompts(s->cur_prompt);
10219 * Send the password packet.
10221 * We pad out the password packet to 256 bytes to make
10222 * it harder for an attacker to find the length of the
10225 * Anyone using a password longer than 256 bytes
10226 * probably doesn't have much to worry about from
10227 * people who find out how long their password is!
10229 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
10230 ssh2_pkt_addstring(s->pktout, ssh->username);
10231 ssh2_pkt_addstring(s->pktout, "ssh-connection");
10232 /* service requested */
10233 ssh2_pkt_addstring(s->pktout, "password");
10234 ssh2_pkt_addbool(s->pktout, FALSE);
10235 ssh2_pkt_addstring(s->pktout, s->password);
10236 ssh2_pkt_send_with_padding(ssh, s->pktout, 256);
10237 logevent("Sent password");
10238 s->type = AUTH_TYPE_PASSWORD;
10241 * Wait for next packet, in case it's a password change
10244 crWaitUntilV(pktin);
10245 changereq_first_time = TRUE;
10247 while (pktin->type == SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ) {
10250 * We're being asked for a new password
10251 * (perhaps not for the first time).
10252 * Loop until the server accepts it.
10255 int got_new = FALSE; /* not live over crReturn */
10256 char *prompt; /* not live over crReturn */
10257 int prompt_len; /* not live over crReturn */
10261 if (changereq_first_time)
10262 msg = "Server requested password change";
10264 msg = "Server rejected new password";
10266 c_write_str(ssh, msg);
10267 c_write_str(ssh, "\r\n");
10270 ssh_pkt_getstring(pktin, &prompt, &prompt_len);
10272 s->cur_prompt = new_prompts(ssh->frontend);
10273 s->cur_prompt->to_server = TRUE;
10274 s->cur_prompt->name = dupstr("New SSH password");
10275 s->cur_prompt->instruction =
10276 dupprintf("%.*s", prompt_len, NULLTOEMPTY(prompt));
10277 s->cur_prompt->instr_reqd = TRUE;
10279 * There's no explicit requirement in the protocol
10280 * for the "old" passwords in the original and
10281 * password-change messages to be the same, and
10282 * apparently some Cisco kit supports password change
10283 * by the user entering a blank password originally
10284 * and the real password subsequently, so,
10285 * reluctantly, we prompt for the old password again.
10287 * (On the other hand, some servers don't even bother
10288 * to check this field.)
10290 add_prompt(s->cur_prompt,
10291 dupstr("Current password (blank for previously entered password): "),
10293 add_prompt(s->cur_prompt, dupstr("Enter new password: "),
10295 add_prompt(s->cur_prompt, dupstr("Confirm new password: "),
10299 * Loop until the user manages to enter the same
10304 ret = get_userpass_input(s->cur_prompt, NULL, 0);
10307 crWaitUntilV(!pktin);
10308 ret = get_userpass_input(s->cur_prompt, in, inlen);
10313 * Failed to get responses. Terminate.
10315 /* burn the evidence */
10316 free_prompts(s->cur_prompt);
10317 smemclr(s->password, strlen(s->password));
10318 sfree(s->password);
10319 ssh_disconnect(ssh, NULL, "Unable to authenticate",
10320 SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER,
10326 * If the user specified a new original password
10327 * (IYSWIM), overwrite any previously specified
10329 * (A side effect is that the user doesn't have to
10330 * re-enter it if they louse up the new password.)
10332 if (s->cur_prompt->prompts[0]->result[0]) {
10333 smemclr(s->password, strlen(s->password));
10334 /* burn the evidence */
10335 sfree(s->password);
10337 dupstr(s->cur_prompt->prompts[0]->result);
10341 * Check the two new passwords match.
10343 got_new = (strcmp(s->cur_prompt->prompts[1]->result,
10344 s->cur_prompt->prompts[2]->result)
10347 /* They don't. Silly user. */
10348 c_write_str(ssh, "Passwords do not match\r\n");
10353 * Send the new password (along with the old one).
10354 * (see above for padding rationale)
10356 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
10357 ssh2_pkt_addstring(s->pktout, ssh->username);
10358 ssh2_pkt_addstring(s->pktout, "ssh-connection");
10359 /* service requested */
10360 ssh2_pkt_addstring(s->pktout, "password");
10361 ssh2_pkt_addbool(s->pktout, TRUE);
10362 ssh2_pkt_addstring(s->pktout, s->password);
10363 ssh2_pkt_addstring(s->pktout,
10364 s->cur_prompt->prompts[1]->result);
10365 free_prompts(s->cur_prompt);
10366 ssh2_pkt_send_with_padding(ssh, s->pktout, 256);
10367 logevent("Sent new password");
10370 * Now see what the server has to say about it.
10371 * (If it's CHANGEREQ again, it's not happy with the
10374 crWaitUntilV(pktin);
10375 changereq_first_time = FALSE;
10380 * We need to reexamine the current pktin at the top
10381 * of the loop. Either:
10382 * - we weren't asked to change password at all, in
10383 * which case it's a SUCCESS or FAILURE with the
10385 * - we sent a new password, and the server was
10386 * either OK with it (SUCCESS or FAILURE w/partial
10387 * success) or unhappy with the _old_ password
10388 * (FAILURE w/o partial success)
10389 * In any of these cases, we go back to the top of
10390 * the loop and start again.
10395 * We don't need the old password any more, in any
10396 * case. Burn the evidence.
10398 smemclr(s->password, strlen(s->password));
10399 sfree(s->password);
10402 char *str = dupprintf("No supported authentication methods available"
10403 " (server sent: %.*s)",
10406 ssh_disconnect(ssh, str,
10407 "No supported authentication methods available",
10408 SSH2_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE,
10418 ssh->packet_dispatch[SSH2_MSG_USERAUTH_BANNER] = NULL;
10420 /* Clear up various bits and pieces from authentication. */
10421 if (s->publickey_blob) {
10422 sfree(s->publickey_algorithm);
10423 sfree(s->publickey_blob);
10424 sfree(s->publickey_comment);
10426 if (s->agent_response)
10427 sfree(s->agent_response);
10429 if (s->userauth_success && !ssh->bare_connection) {
10431 * We've just received USERAUTH_SUCCESS, and we haven't sent any
10432 * packets since. Signal the transport layer to consider enacting
10433 * delayed compression.
10435 * (Relying on we_are_in is not sufficient, as
10436 * draft-miller-secsh-compression-delayed is quite clear that it
10437 * triggers on USERAUTH_SUCCESS specifically, and we_are_in can
10438 * become set for other reasons.)
10440 do_ssh2_transport(ssh, "enabling delayed compression", -2, NULL);
10443 ssh->channels = newtree234(ssh_channelcmp);
10446 * Set up handlers for some connection protocol messages, so we
10447 * don't have to handle them repeatedly in this coroutine.
10449 ssh->packet_dispatch[SSH2_MSG_CHANNEL_WINDOW_ADJUST] =
10450 ssh2_msg_channel_window_adjust;
10451 ssh->packet_dispatch[SSH2_MSG_GLOBAL_REQUEST] =
10452 ssh2_msg_global_request;
10455 * Create the main session channel.
10457 if (conf_get_int(ssh->conf, CONF_ssh_no_shell)) {
10458 ssh->mainchan = NULL;
10460 ssh->mainchan = snew(struct ssh_channel);
10461 ssh->mainchan->ssh = ssh;
10462 ssh2_channel_init(ssh->mainchan);
10464 if (*conf_get_str(ssh->conf, CONF_ssh_nc_host)) {
10466 * Just start a direct-tcpip channel and use it as the main
10469 ssh_send_port_open(ssh->mainchan,
10470 conf_get_str(ssh->conf, CONF_ssh_nc_host),
10471 conf_get_int(ssh->conf, CONF_ssh_nc_port),
10473 ssh->ncmode = TRUE;
10475 s->pktout = ssh2_chanopen_init(ssh->mainchan, "session");
10476 logevent("Opening session as main channel");
10477 ssh2_pkt_send(ssh, s->pktout);
10478 ssh->ncmode = FALSE;
10480 crWaitUntilV(pktin);
10481 if (pktin->type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
10482 bombout(("Server refused to open channel"));
10484 /* FIXME: error data comes back in FAILURE packet */
10486 if (ssh_pkt_getuint32(pktin) != ssh->mainchan->localid) {
10487 bombout(("Server's channel confirmation cited wrong channel"));
10490 ssh->mainchan->remoteid = ssh_pkt_getuint32(pktin);
10491 ssh->mainchan->halfopen = FALSE;
10492 ssh->mainchan->type = CHAN_MAINSESSION;
10493 ssh->mainchan->v.v2.remwindow = ssh_pkt_getuint32(pktin);
10494 ssh->mainchan->v.v2.remmaxpkt = ssh_pkt_getuint32(pktin);
10495 add234(ssh->channels, ssh->mainchan);
10496 update_specials_menu(ssh->frontend);
10497 logevent("Opened main channel");
10501 * Now we have a channel, make dispatch table entries for
10502 * general channel-based messages.
10504 ssh->packet_dispatch[SSH2_MSG_CHANNEL_DATA] =
10505 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EXTENDED_DATA] =
10506 ssh2_msg_channel_data;
10507 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EOF] = ssh2_msg_channel_eof;
10508 ssh->packet_dispatch[SSH2_MSG_CHANNEL_CLOSE] = ssh2_msg_channel_close;
10509 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_CONFIRMATION] =
10510 ssh2_msg_channel_open_confirmation;
10511 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_FAILURE] =
10512 ssh2_msg_channel_open_failure;
10513 ssh->packet_dispatch[SSH2_MSG_CHANNEL_REQUEST] =
10514 ssh2_msg_channel_request;
10515 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN] =
10516 ssh2_msg_channel_open;
10517 ssh->packet_dispatch[SSH2_MSG_CHANNEL_SUCCESS] = ssh2_msg_channel_response;
10518 ssh->packet_dispatch[SSH2_MSG_CHANNEL_FAILURE] = ssh2_msg_channel_response;
10521 * Now the connection protocol is properly up and running, with
10522 * all those dispatch table entries, so it's safe to let
10523 * downstreams start trying to open extra channels through us.
10525 if (ssh->connshare)
10526 share_activate(ssh->connshare, ssh->v_s);
10528 if (ssh->mainchan && ssh_is_simple(ssh)) {
10530 * This message indicates to the server that we promise
10531 * not to try to run any other channel in parallel with
10532 * this one, so it's safe for it to advertise a very large
10533 * window and leave the flow control to TCP.
10535 s->pktout = ssh2_chanreq_init(ssh->mainchan,
10536 "simple@putty.projects.tartarus.org",
10538 ssh2_pkt_send(ssh, s->pktout);
10542 * Enable port forwardings.
10544 ssh_setup_portfwd(ssh, ssh->conf);
10546 if (ssh->mainchan && !ssh->ncmode) {
10548 * Send the CHANNEL_REQUESTS for the main session channel.
10549 * Each one is handled by its own little asynchronous
10553 /* Potentially enable X11 forwarding. */
10554 if (conf_get_int(ssh->conf, CONF_x11_forward)) {
10556 x11_setup_display(conf_get_str(ssh->conf, CONF_x11_display),
10558 if (!ssh->x11disp) {
10559 /* FIXME: return an error message from x11_setup_display */
10560 logevent("X11 forwarding not enabled: unable to"
10561 " initialise X display");
10563 ssh->x11auth = x11_invent_fake_auth
10564 (ssh->x11authtree, conf_get_int(ssh->conf, CONF_x11_auth));
10565 ssh->x11auth->disp = ssh->x11disp;
10567 ssh2_setup_x11(ssh->mainchan, NULL, NULL);
10571 /* Potentially enable agent forwarding. */
10572 if (ssh_agent_forwarding_permitted(ssh))
10573 ssh2_setup_agent(ssh->mainchan, NULL, NULL);
10575 /* Now allocate a pty for the session. */
10576 if (!conf_get_int(ssh->conf, CONF_nopty))
10577 ssh2_setup_pty(ssh->mainchan, NULL, NULL);
10579 /* Send environment variables. */
10580 ssh2_setup_env(ssh->mainchan, NULL, NULL);
10583 * Start a shell or a remote command. We may have to attempt
10584 * this twice if the config data has provided a second choice
10591 if (ssh->fallback_cmd) {
10592 subsys = conf_get_int(ssh->conf, CONF_ssh_subsys2);
10593 cmd = conf_get_str(ssh->conf, CONF_remote_cmd2);
10595 subsys = conf_get_int(ssh->conf, CONF_ssh_subsys);
10596 cmd = conf_get_str(ssh->conf, CONF_remote_cmd);
10600 s->pktout = ssh2_chanreq_init(ssh->mainchan, "subsystem",
10601 ssh2_response_authconn, NULL);
10602 ssh2_pkt_addstring(s->pktout, cmd);
10604 s->pktout = ssh2_chanreq_init(ssh->mainchan, "exec",
10605 ssh2_response_authconn, NULL);
10606 ssh2_pkt_addstring(s->pktout, cmd);
10608 s->pktout = ssh2_chanreq_init(ssh->mainchan, "shell",
10609 ssh2_response_authconn, NULL);
10611 ssh2_pkt_send(ssh, s->pktout);
10613 crWaitUntilV(pktin);
10615 if (pktin->type != SSH2_MSG_CHANNEL_SUCCESS) {
10616 if (pktin->type != SSH2_MSG_CHANNEL_FAILURE) {
10617 bombout(("Unexpected response to shell/command request:"
10618 " packet type %d", pktin->type));
10622 * We failed to start the command. If this is the
10623 * fallback command, we really are finished; if it's
10624 * not, and if the fallback command exists, try falling
10625 * back to it before complaining.
10627 if (!ssh->fallback_cmd &&
10628 *conf_get_str(ssh->conf, CONF_remote_cmd2)) {
10629 logevent("Primary command failed; attempting fallback");
10630 ssh->fallback_cmd = TRUE;
10633 bombout(("Server refused to start a shell/command"));
10636 logevent("Started a shell/command");
10641 ssh->editing = ssh->echoing = TRUE;
10644 ssh->state = SSH_STATE_SESSION;
10645 if (ssh->size_needed)
10646 ssh_size(ssh, ssh->term_width, ssh->term_height);
10647 if (ssh->eof_needed)
10648 ssh_special(ssh, TS_EOF);
10654 ldisc_echoedit_update(ssh->ldisc); /* cause ldisc to notice changes */
10659 s->try_send = FALSE;
10663 * _All_ the connection-layer packets we expect to
10664 * receive are now handled by the dispatch table.
10665 * Anything that reaches here must be bogus.
10668 bombout(("Strange packet received: type %d", pktin->type));
10670 } else if (ssh->mainchan) {
10672 * We have spare data. Add it to the channel buffer.
10674 ssh2_add_channel_data(ssh->mainchan, (char *)in, inlen);
10675 s->try_send = TRUE;
10679 struct ssh_channel *c;
10681 * Try to send data on all channels if we can.
10683 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++)
10684 if (c->type != CHAN_SHARING)
10685 ssh2_try_send_and_unthrottle(ssh, c);
10693 * Handlers for SSH-2 messages that might arrive at any moment.
10695 static void ssh2_msg_disconnect(Ssh ssh, struct Packet *pktin)
10697 /* log reason code in disconnect message */
10699 int reason, msglen;
10701 reason = ssh_pkt_getuint32(pktin);
10702 ssh_pkt_getstring(pktin, &msg, &msglen);
10704 if (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) {
10705 buf = dupprintf("Received disconnect message (%s)",
10706 ssh2_disconnect_reasons[reason]);
10708 buf = dupprintf("Received disconnect message (unknown"
10709 " type %d)", reason);
10713 buf = dupprintf("Disconnection message text: %.*s",
10714 msglen, NULLTOEMPTY(msg));
10716 bombout(("Server sent disconnect message\ntype %d (%s):\n\"%.*s\"",
10718 (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) ?
10719 ssh2_disconnect_reasons[reason] : "unknown",
10720 msglen, NULLTOEMPTY(msg)));
10724 static void ssh2_msg_debug(Ssh ssh, struct Packet *pktin)
10726 /* log the debug message */
10730 /* XXX maybe we should actually take notice of the return value */
10731 ssh2_pkt_getbool(pktin);
10732 ssh_pkt_getstring(pktin, &msg, &msglen);
10734 logeventf(ssh, "Remote debug message: %.*s", msglen, NULLTOEMPTY(msg));
10737 static void ssh2_msg_transport(Ssh ssh, struct Packet *pktin)
10739 do_ssh2_transport(ssh, NULL, 0, pktin);
10743 * Called if we receive a packet that isn't allowed by the protocol.
10744 * This only applies to packets whose meaning PuTTY understands.
10745 * Entirely unknown packets are handled below.
10747 static void ssh2_msg_unexpected(Ssh ssh, struct Packet *pktin)
10749 char *buf = dupprintf("Server protocol violation: unexpected %s packet",
10750 ssh2_pkt_type(ssh->pkt_kctx, ssh->pkt_actx,
10752 ssh_disconnect(ssh, NULL, buf, SSH2_DISCONNECT_PROTOCOL_ERROR, FALSE);
10756 static void ssh2_msg_something_unimplemented(Ssh ssh, struct Packet *pktin)
10758 struct Packet *pktout;
10759 pktout = ssh2_pkt_init(SSH2_MSG_UNIMPLEMENTED);
10760 ssh2_pkt_adduint32(pktout, pktin->sequence);
10762 * UNIMPLEMENTED messages MUST appear in the same order as the
10763 * messages they respond to. Hence, never queue them.
10765 ssh2_pkt_send_noqueue(ssh, pktout);
10769 * Handle the top-level SSH-2 protocol.
10771 static void ssh2_protocol_setup(Ssh ssh)
10776 * Most messages cause SSH2_MSG_UNIMPLEMENTED.
10778 for (i = 0; i < 256; i++)
10779 ssh->packet_dispatch[i] = ssh2_msg_something_unimplemented;
10782 * Initially, we only accept transport messages (and a few generic
10783 * ones). do_ssh2_authconn will add more when it starts.
10784 * Messages that are understood but not currently acceptable go to
10785 * ssh2_msg_unexpected.
10787 ssh->packet_dispatch[SSH2_MSG_UNIMPLEMENTED] = ssh2_msg_unexpected;
10788 ssh->packet_dispatch[SSH2_MSG_SERVICE_REQUEST] = ssh2_msg_unexpected;
10789 ssh->packet_dispatch[SSH2_MSG_SERVICE_ACCEPT] = ssh2_msg_unexpected;
10790 ssh->packet_dispatch[SSH2_MSG_KEXINIT] = ssh2_msg_transport;
10791 ssh->packet_dispatch[SSH2_MSG_NEWKEYS] = ssh2_msg_transport;
10792 ssh->packet_dispatch[SSH2_MSG_KEXDH_INIT] = ssh2_msg_transport;
10793 ssh->packet_dispatch[SSH2_MSG_KEXDH_REPLY] = ssh2_msg_transport;
10794 /* ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_REQUEST] = ssh2_msg_transport; duplicate case value */
10795 /* ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_GROUP] = ssh2_msg_transport; duplicate case value */
10796 ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_INIT] = ssh2_msg_transport;
10797 ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_REPLY] = ssh2_msg_transport;
10798 ssh->packet_dispatch[SSH2_MSG_USERAUTH_REQUEST] = ssh2_msg_unexpected;
10799 ssh->packet_dispatch[SSH2_MSG_USERAUTH_FAILURE] = ssh2_msg_unexpected;
10800 ssh->packet_dispatch[SSH2_MSG_USERAUTH_SUCCESS] = ssh2_msg_unexpected;
10801 ssh->packet_dispatch[SSH2_MSG_USERAUTH_BANNER] = ssh2_msg_unexpected;
10802 ssh->packet_dispatch[SSH2_MSG_USERAUTH_PK_OK] = ssh2_msg_unexpected;
10803 /* ssh->packet_dispatch[SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ] = ssh2_msg_unexpected; duplicate case value */
10804 /* ssh->packet_dispatch[SSH2_MSG_USERAUTH_INFO_REQUEST] = ssh2_msg_unexpected; duplicate case value */
10805 ssh->packet_dispatch[SSH2_MSG_USERAUTH_INFO_RESPONSE] = ssh2_msg_unexpected;
10806 ssh->packet_dispatch[SSH2_MSG_GLOBAL_REQUEST] = ssh2_msg_unexpected;
10807 ssh->packet_dispatch[SSH2_MSG_REQUEST_SUCCESS] = ssh2_msg_unexpected;
10808 ssh->packet_dispatch[SSH2_MSG_REQUEST_FAILURE] = ssh2_msg_unexpected;
10809 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN] = ssh2_msg_unexpected;
10810 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_CONFIRMATION] = ssh2_msg_unexpected;
10811 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_FAILURE] = ssh2_msg_unexpected;
10812 ssh->packet_dispatch[SSH2_MSG_CHANNEL_WINDOW_ADJUST] = ssh2_msg_unexpected;
10813 ssh->packet_dispatch[SSH2_MSG_CHANNEL_DATA] = ssh2_msg_unexpected;
10814 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EXTENDED_DATA] = ssh2_msg_unexpected;
10815 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EOF] = ssh2_msg_unexpected;
10816 ssh->packet_dispatch[SSH2_MSG_CHANNEL_CLOSE] = ssh2_msg_unexpected;
10817 ssh->packet_dispatch[SSH2_MSG_CHANNEL_REQUEST] = ssh2_msg_unexpected;
10818 ssh->packet_dispatch[SSH2_MSG_CHANNEL_SUCCESS] = ssh2_msg_unexpected;
10819 ssh->packet_dispatch[SSH2_MSG_CHANNEL_FAILURE] = ssh2_msg_unexpected;
10822 * These messages have a special handler from the start.
10824 ssh->packet_dispatch[SSH2_MSG_DISCONNECT] = ssh2_msg_disconnect;
10825 ssh->packet_dispatch[SSH2_MSG_IGNORE] = ssh_msg_ignore; /* shared with SSH-1 */
10826 ssh->packet_dispatch[SSH2_MSG_DEBUG] = ssh2_msg_debug;
10829 static void ssh2_bare_connection_protocol_setup(Ssh ssh)
10834 * Most messages cause SSH2_MSG_UNIMPLEMENTED.
10836 for (i = 0; i < 256; i++)
10837 ssh->packet_dispatch[i] = ssh2_msg_something_unimplemented;
10840 * Initially, we set all ssh-connection messages to 'unexpected';
10841 * do_ssh2_authconn will fill things in properly. We also handle a
10842 * couple of messages from the transport protocol which aren't
10843 * related to key exchange (UNIMPLEMENTED, IGNORE, DEBUG,
10846 ssh->packet_dispatch[SSH2_MSG_GLOBAL_REQUEST] = ssh2_msg_unexpected;
10847 ssh->packet_dispatch[SSH2_MSG_REQUEST_SUCCESS] = ssh2_msg_unexpected;
10848 ssh->packet_dispatch[SSH2_MSG_REQUEST_FAILURE] = ssh2_msg_unexpected;
10849 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN] = ssh2_msg_unexpected;
10850 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_CONFIRMATION] = ssh2_msg_unexpected;
10851 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_FAILURE] = ssh2_msg_unexpected;
10852 ssh->packet_dispatch[SSH2_MSG_CHANNEL_WINDOW_ADJUST] = ssh2_msg_unexpected;
10853 ssh->packet_dispatch[SSH2_MSG_CHANNEL_DATA] = ssh2_msg_unexpected;
10854 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EXTENDED_DATA] = ssh2_msg_unexpected;
10855 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EOF] = ssh2_msg_unexpected;
10856 ssh->packet_dispatch[SSH2_MSG_CHANNEL_CLOSE] = ssh2_msg_unexpected;
10857 ssh->packet_dispatch[SSH2_MSG_CHANNEL_REQUEST] = ssh2_msg_unexpected;
10858 ssh->packet_dispatch[SSH2_MSG_CHANNEL_SUCCESS] = ssh2_msg_unexpected;
10859 ssh->packet_dispatch[SSH2_MSG_CHANNEL_FAILURE] = ssh2_msg_unexpected;
10861 ssh->packet_dispatch[SSH2_MSG_UNIMPLEMENTED] = ssh2_msg_unexpected;
10864 * These messages have a special handler from the start.
10866 ssh->packet_dispatch[SSH2_MSG_DISCONNECT] = ssh2_msg_disconnect;
10867 ssh->packet_dispatch[SSH2_MSG_IGNORE] = ssh_msg_ignore;
10868 ssh->packet_dispatch[SSH2_MSG_DEBUG] = ssh2_msg_debug;
10871 static void ssh2_timer(void *ctx, unsigned long now)
10873 Ssh ssh = (Ssh)ctx;
10875 if (ssh->state == SSH_STATE_CLOSED)
10878 if (!ssh->kex_in_progress && !ssh->bare_connection &&
10879 conf_get_int(ssh->conf, CONF_ssh_rekey_time) != 0 &&
10880 now == ssh->next_rekey) {
10881 do_ssh2_transport(ssh, "timeout", -1, NULL);
10885 static void ssh2_protocol(Ssh ssh, const void *vin, int inlen,
10886 struct Packet *pktin)
10888 const unsigned char *in = (const unsigned char *)vin;
10889 if (ssh->state == SSH_STATE_CLOSED)
10893 ssh->incoming_data_size += pktin->encrypted_len;
10894 if (!ssh->kex_in_progress &&
10895 ssh->max_data_size != 0 &&
10896 ssh->incoming_data_size > ssh->max_data_size)
10897 do_ssh2_transport(ssh, "too much data received", -1, NULL);
10901 ssh->packet_dispatch[pktin->type](ssh, pktin);
10902 else if (!ssh->protocol_initial_phase_done)
10903 do_ssh2_transport(ssh, in, inlen, pktin);
10905 do_ssh2_authconn(ssh, in, inlen, pktin);
10908 static void ssh2_bare_connection_protocol(Ssh ssh, const void *vin, int inlen,
10909 struct Packet *pktin)
10911 const unsigned char *in = (const unsigned char *)vin;
10912 if (ssh->state == SSH_STATE_CLOSED)
10916 ssh->packet_dispatch[pktin->type](ssh, pktin);
10918 do_ssh2_authconn(ssh, in, inlen, pktin);
10921 static void ssh_cache_conf_values(Ssh ssh)
10923 ssh->logomitdata = conf_get_int(ssh->conf, CONF_logomitdata);
10927 * Called to set up the connection.
10929 * Returns an error message, or NULL on success.
10931 static const char *ssh_init(void *frontend_handle, void **backend_handle,
10933 const char *host, int port, char **realhost,
10934 int nodelay, int keepalive)
10939 ssh = snew(struct ssh_tag);
10940 ssh->conf = conf_copy(conf);
10941 ssh_cache_conf_values(ssh);
10942 ssh->version = 0; /* when not ready yet */
10944 ssh->cipher = NULL;
10945 ssh->v1_cipher_ctx = NULL;
10946 ssh->crcda_ctx = NULL;
10947 ssh->cscipher = NULL;
10948 ssh->cs_cipher_ctx = NULL;
10949 ssh->sccipher = NULL;
10950 ssh->sc_cipher_ctx = NULL;
10952 ssh->cs_mac_ctx = NULL;
10954 ssh->sc_mac_ctx = NULL;
10955 ssh->cscomp = NULL;
10956 ssh->cs_comp_ctx = NULL;
10957 ssh->sccomp = NULL;
10958 ssh->sc_comp_ctx = NULL;
10960 ssh->kex_ctx = NULL;
10961 ssh->hostkey = NULL;
10962 ssh->hostkey_str = NULL;
10963 ssh->exitcode = -1;
10964 ssh->close_expected = FALSE;
10965 ssh->clean_exit = FALSE;
10966 ssh->state = SSH_STATE_PREPACKET;
10967 ssh->size_needed = FALSE;
10968 ssh->eof_needed = FALSE;
10970 ssh->logctx = NULL;
10971 ssh->deferred_send_data = NULL;
10972 ssh->deferred_len = 0;
10973 ssh->deferred_size = 0;
10974 ssh->fallback_cmd = 0;
10975 ssh->pkt_kctx = SSH2_PKTCTX_NOKEX;
10976 ssh->pkt_actx = SSH2_PKTCTX_NOAUTH;
10977 ssh->x11disp = NULL;
10978 ssh->x11auth = NULL;
10979 ssh->x11authtree = newtree234(x11_authcmp);
10980 ssh->v1_compressing = FALSE;
10981 ssh->v2_outgoing_sequence = 0;
10982 ssh->ssh1_rdpkt_crstate = 0;
10983 ssh->ssh2_rdpkt_crstate = 0;
10984 ssh->ssh2_bare_rdpkt_crstate = 0;
10985 ssh->ssh_gotdata_crstate = 0;
10986 ssh->do_ssh1_connection_crstate = 0;
10987 ssh->do_ssh_init_state = NULL;
10988 ssh->do_ssh_connection_init_state = NULL;
10989 ssh->do_ssh1_login_state = NULL;
10990 ssh->do_ssh2_transport_state = NULL;
10991 ssh->do_ssh2_authconn_state = NULL;
10994 ssh->mainchan = NULL;
10995 ssh->throttled_all = 0;
10996 ssh->v1_stdout_throttling = 0;
10998 ssh->queuelen = ssh->queuesize = 0;
10999 ssh->queueing = FALSE;
11000 ssh->qhead = ssh->qtail = NULL;
11001 ssh->deferred_rekey_reason = NULL;
11002 bufchain_init(&ssh->queued_incoming_data);
11003 ssh->frozen = FALSE;
11004 ssh->username = NULL;
11005 ssh->sent_console_eof = FALSE;
11006 ssh->got_pty = FALSE;
11007 ssh->bare_connection = FALSE;
11008 ssh->X11_fwd_enabled = FALSE;
11009 ssh->connshare = NULL;
11010 ssh->attempting_connshare = FALSE;
11011 ssh->session_started = FALSE;
11012 ssh->specials = NULL;
11014 *backend_handle = ssh;
11017 if (crypto_startup() == 0)
11018 return "Microsoft high encryption pack not installed!";
11021 ssh->frontend = frontend_handle;
11022 ssh->term_width = conf_get_int(ssh->conf, CONF_width);
11023 ssh->term_height = conf_get_int(ssh->conf, CONF_height);
11025 ssh->channels = NULL;
11026 ssh->rportfwds = NULL;
11027 ssh->portfwds = NULL;
11032 ssh->conn_throttle_count = 0;
11033 ssh->overall_bufsize = 0;
11034 ssh->fallback_cmd = 0;
11036 ssh->protocol = NULL;
11038 ssh->protocol_initial_phase_done = FALSE;
11040 ssh->pinger = NULL;
11042 ssh->incoming_data_size = ssh->outgoing_data_size =
11043 ssh->deferred_data_size = 0L;
11044 ssh->max_data_size = parse_blocksize(conf_get_str(ssh->conf,
11045 CONF_ssh_rekey_data));
11046 ssh->kex_in_progress = FALSE;
11049 ssh->gsslibs = NULL;
11052 random_ref(); /* do this now - may be needed by sharing setup code */
11054 p = connect_to_host(ssh, host, port, realhost, nodelay, keepalive);
11063 static void ssh_free(void *handle)
11065 Ssh ssh = (Ssh) handle;
11066 struct ssh_channel *c;
11067 struct ssh_rportfwd *pf;
11068 struct X11FakeAuth *auth;
11070 if (ssh->v1_cipher_ctx)
11071 ssh->cipher->free_context(ssh->v1_cipher_ctx);
11072 if (ssh->cs_cipher_ctx)
11073 ssh->cscipher->free_context(ssh->cs_cipher_ctx);
11074 if (ssh->sc_cipher_ctx)
11075 ssh->sccipher->free_context(ssh->sc_cipher_ctx);
11076 if (ssh->cs_mac_ctx)
11077 ssh->csmac->free_context(ssh->cs_mac_ctx);
11078 if (ssh->sc_mac_ctx)
11079 ssh->scmac->free_context(ssh->sc_mac_ctx);
11080 if (ssh->cs_comp_ctx) {
11082 ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
11084 zlib_compress_cleanup(ssh->cs_comp_ctx);
11086 if (ssh->sc_comp_ctx) {
11088 ssh->sccomp->decompress_cleanup(ssh->sc_comp_ctx);
11090 zlib_decompress_cleanup(ssh->sc_comp_ctx);
11093 dh_cleanup(ssh->kex_ctx);
11094 sfree(ssh->savedhost);
11096 while (ssh->queuelen-- > 0)
11097 ssh_free_packet(ssh->queue[ssh->queuelen]);
11100 while (ssh->qhead) {
11101 struct queued_handler *qh = ssh->qhead;
11102 ssh->qhead = qh->next;
11105 ssh->qhead = ssh->qtail = NULL;
11107 if (ssh->channels) {
11108 while ((c = delpos234(ssh->channels, 0)) != NULL) {
11111 if (c->u.x11.xconn != NULL)
11112 x11_close(c->u.x11.xconn);
11114 case CHAN_SOCKDATA:
11115 case CHAN_SOCKDATA_DORMANT:
11116 if (c->u.pfd.pf != NULL)
11117 pfd_close(c->u.pfd.pf);
11120 if (ssh->version == 2) {
11121 struct outstanding_channel_request *ocr, *nocr;
11122 ocr = c->v.v2.chanreq_head;
11124 ocr->handler(c, NULL, ocr->ctx);
11129 bufchain_clear(&c->v.v2.outbuffer);
11133 freetree234(ssh->channels);
11134 ssh->channels = NULL;
11137 if (ssh->connshare)
11138 sharestate_free(ssh->connshare);
11140 if (ssh->rportfwds) {
11141 while ((pf = delpos234(ssh->rportfwds, 0)) != NULL)
11143 freetree234(ssh->rportfwds);
11144 ssh->rportfwds = NULL;
11146 sfree(ssh->deferred_send_data);
11148 x11_free_display(ssh->x11disp);
11149 while ((auth = delpos234(ssh->x11authtree, 0)) != NULL)
11150 x11_free_fake_auth(auth);
11151 freetree234(ssh->x11authtree);
11152 sfree(ssh->do_ssh_init_state);
11153 sfree(ssh->do_ssh1_login_state);
11154 sfree(ssh->do_ssh2_transport_state);
11155 sfree(ssh->do_ssh2_authconn_state);
11158 sfree(ssh->fullhostname);
11159 sfree(ssh->hostkey_str);
11160 sfree(ssh->specials);
11161 if (ssh->crcda_ctx) {
11162 crcda_free_context(ssh->crcda_ctx);
11163 ssh->crcda_ctx = NULL;
11166 ssh_do_close(ssh, TRUE);
11167 expire_timer_context(ssh);
11169 pinger_free(ssh->pinger);
11170 bufchain_clear(&ssh->queued_incoming_data);
11171 sfree(ssh->username);
11172 conf_free(ssh->conf);
11175 ssh_gss_cleanup(ssh->gsslibs);
11183 * Reconfigure the SSH backend.
11185 static void ssh_reconfig(void *handle, Conf *conf)
11187 Ssh ssh = (Ssh) handle;
11188 const char *rekeying = NULL;
11189 int rekey_mandatory = FALSE;
11190 unsigned long old_max_data_size;
11193 pinger_reconfig(ssh->pinger, ssh->conf, conf);
11195 ssh_setup_portfwd(ssh, conf);
11197 rekey_time = conf_get_int(conf, CONF_ssh_rekey_time);
11198 if (conf_get_int(ssh->conf, CONF_ssh_rekey_time) != rekey_time &&
11200 unsigned long new_next = ssh->last_rekey + rekey_time*60*TICKSPERSEC;
11201 unsigned long now = GETTICKCOUNT();
11203 if (now - ssh->last_rekey > rekey_time*60*TICKSPERSEC) {
11204 rekeying = "timeout shortened";
11206 ssh->next_rekey = schedule_timer(new_next - now, ssh2_timer, ssh);
11210 old_max_data_size = ssh->max_data_size;
11211 ssh->max_data_size = parse_blocksize(conf_get_str(ssh->conf,
11212 CONF_ssh_rekey_data));
11213 if (old_max_data_size != ssh->max_data_size &&
11214 ssh->max_data_size != 0) {
11215 if (ssh->outgoing_data_size > ssh->max_data_size ||
11216 ssh->incoming_data_size > ssh->max_data_size)
11217 rekeying = "data limit lowered";
11220 if (conf_get_int(ssh->conf, CONF_compression) !=
11221 conf_get_int(conf, CONF_compression)) {
11222 rekeying = "compression setting changed";
11223 rekey_mandatory = TRUE;
11226 for (i = 0; i < CIPHER_MAX; i++)
11227 if (conf_get_int_int(ssh->conf, CONF_ssh_cipherlist, i) !=
11228 conf_get_int_int(conf, CONF_ssh_cipherlist, i)) {
11229 rekeying = "cipher settings changed";
11230 rekey_mandatory = TRUE;
11232 if (conf_get_int(ssh->conf, CONF_ssh2_des_cbc) !=
11233 conf_get_int(conf, CONF_ssh2_des_cbc)) {
11234 rekeying = "cipher settings changed";
11235 rekey_mandatory = TRUE;
11238 conf_free(ssh->conf);
11239 ssh->conf = conf_copy(conf);
11240 ssh_cache_conf_values(ssh);
11242 if (!ssh->bare_connection && rekeying) {
11243 if (!ssh->kex_in_progress) {
11244 do_ssh2_transport(ssh, rekeying, -1, NULL);
11245 } else if (rekey_mandatory) {
11246 ssh->deferred_rekey_reason = rekeying;
11252 * Called to send data down the SSH connection.
11254 static int ssh_send(void *handle, const char *buf, int len)
11256 Ssh ssh = (Ssh) handle;
11258 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
11261 ssh->protocol(ssh, (const unsigned char *)buf, len, 0);
11263 return ssh_sendbuffer(ssh);
11267 * Called to query the current amount of buffered stdin data.
11269 static int ssh_sendbuffer(void *handle)
11271 Ssh ssh = (Ssh) handle;
11272 int override_value;
11274 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
11278 * If the SSH socket itself has backed up, add the total backup
11279 * size on that to any individual buffer on the stdin channel.
11281 override_value = 0;
11282 if (ssh->throttled_all)
11283 override_value = ssh->overall_bufsize;
11285 if (ssh->version == 1) {
11286 return override_value;
11287 } else if (ssh->version == 2) {
11288 if (!ssh->mainchan)
11289 return override_value;
11291 return (override_value +
11292 bufchain_size(&ssh->mainchan->v.v2.outbuffer));
11299 * Called to set the size of the window from SSH's POV.
11301 static void ssh_size(void *handle, int width, int height)
11303 Ssh ssh = (Ssh) handle;
11304 struct Packet *pktout;
11306 ssh->term_width = width;
11307 ssh->term_height = height;
11309 switch (ssh->state) {
11310 case SSH_STATE_BEFORE_SIZE:
11311 case SSH_STATE_PREPACKET:
11312 case SSH_STATE_CLOSED:
11313 break; /* do nothing */
11314 case SSH_STATE_INTERMED:
11315 ssh->size_needed = TRUE; /* buffer for later */
11317 case SSH_STATE_SESSION:
11318 if (!conf_get_int(ssh->conf, CONF_nopty)) {
11319 if (ssh->version == 1) {
11320 send_packet(ssh, SSH1_CMSG_WINDOW_SIZE,
11321 PKT_INT, ssh->term_height,
11322 PKT_INT, ssh->term_width,
11323 PKT_INT, 0, PKT_INT, 0, PKT_END);
11324 } else if (ssh->mainchan) {
11325 pktout = ssh2_chanreq_init(ssh->mainchan, "window-change",
11327 ssh2_pkt_adduint32(pktout, ssh->term_width);
11328 ssh2_pkt_adduint32(pktout, ssh->term_height);
11329 ssh2_pkt_adduint32(pktout, 0);
11330 ssh2_pkt_adduint32(pktout, 0);
11331 ssh2_pkt_send(ssh, pktout);
11339 * Return a list of the special codes that make sense in this
11342 static const struct telnet_special *ssh_get_specials(void *handle)
11344 static const struct telnet_special ssh1_ignore_special[] = {
11345 {"IGNORE message", TS_NOP}
11347 static const struct telnet_special ssh2_ignore_special[] = {
11348 {"IGNORE message", TS_NOP},
11350 static const struct telnet_special ssh2_rekey_special[] = {
11351 {"Repeat key exchange", TS_REKEY},
11353 static const struct telnet_special ssh2_session_specials[] = {
11356 /* These are the signal names defined by RFC 4254.
11357 * They include all the ISO C signals, but are a subset of the POSIX
11358 * required signals. */
11359 {"SIGINT (Interrupt)", TS_SIGINT},
11360 {"SIGTERM (Terminate)", TS_SIGTERM},
11361 {"SIGKILL (Kill)", TS_SIGKILL},
11362 {"SIGQUIT (Quit)", TS_SIGQUIT},
11363 {"SIGHUP (Hangup)", TS_SIGHUP},
11364 {"More signals", TS_SUBMENU},
11365 {"SIGABRT", TS_SIGABRT}, {"SIGALRM", TS_SIGALRM},
11366 {"SIGFPE", TS_SIGFPE}, {"SIGILL", TS_SIGILL},
11367 {"SIGPIPE", TS_SIGPIPE}, {"SIGSEGV", TS_SIGSEGV},
11368 {"SIGUSR1", TS_SIGUSR1}, {"SIGUSR2", TS_SIGUSR2},
11369 {NULL, TS_EXITMENU}
11371 static const struct telnet_special specials_end[] = {
11372 {NULL, TS_EXITMENU}
11375 struct telnet_special *specials = NULL;
11376 int nspecials = 0, specialsize = 0;
11378 Ssh ssh = (Ssh) handle;
11380 sfree(ssh->specials);
11382 #define ADD_SPECIALS(name) do \
11384 int len = lenof(name); \
11385 if (nspecials + len > specialsize) { \
11386 specialsize = (nspecials + len) * 5 / 4 + 32; \
11387 specials = sresize(specials, specialsize, struct telnet_special); \
11389 memcpy(specials+nspecials, name, len*sizeof(struct telnet_special)); \
11390 nspecials += len; \
11393 if (ssh->version == 1) {
11394 /* Don't bother offering IGNORE if we've decided the remote
11395 * won't cope with it, since we wouldn't bother sending it if
11397 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE))
11398 ADD_SPECIALS(ssh1_ignore_special);
11399 } else if (ssh->version == 2) {
11400 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH2_IGNORE))
11401 ADD_SPECIALS(ssh2_ignore_special);
11402 if (!(ssh->remote_bugs & BUG_SSH2_REKEY) && !ssh->bare_connection)
11403 ADD_SPECIALS(ssh2_rekey_special);
11405 ADD_SPECIALS(ssh2_session_specials);
11406 } /* else we're not ready yet */
11409 ADD_SPECIALS(specials_end);
11411 ssh->specials = specials;
11418 #undef ADD_SPECIALS
11422 * Send special codes. TS_EOF is useful for `plink', so you
11423 * can send an EOF and collect resulting output (e.g. `plink
11426 static void ssh_special(void *handle, Telnet_Special code)
11428 Ssh ssh = (Ssh) handle;
11429 struct Packet *pktout;
11431 if (code == TS_EOF) {
11432 if (ssh->state != SSH_STATE_SESSION) {
11434 * Buffer the EOF in case we are pre-SESSION, so we can
11435 * send it as soon as we reach SESSION.
11437 if (code == TS_EOF)
11438 ssh->eof_needed = TRUE;
11441 if (ssh->version == 1) {
11442 send_packet(ssh, SSH1_CMSG_EOF, PKT_END);
11443 } else if (ssh->mainchan) {
11444 sshfwd_write_eof(ssh->mainchan);
11445 ssh->send_ok = 0; /* now stop trying to read from stdin */
11447 logevent("Sent EOF message");
11448 } else if (code == TS_PING || code == TS_NOP) {
11449 if (ssh->state == SSH_STATE_CLOSED
11450 || ssh->state == SSH_STATE_PREPACKET) return;
11451 if (ssh->version == 1) {
11452 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE))
11453 send_packet(ssh, SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
11455 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH2_IGNORE)) {
11456 pktout = ssh2_pkt_init(SSH2_MSG_IGNORE);
11457 ssh2_pkt_addstring_start(pktout);
11458 ssh2_pkt_send_noqueue(ssh, pktout);
11461 } else if (code == TS_REKEY) {
11462 if (!ssh->kex_in_progress && !ssh->bare_connection &&
11463 ssh->version == 2) {
11464 do_ssh2_transport(ssh, "at user request", -1, NULL);
11466 } else if (code == TS_BRK) {
11467 if (ssh->state == SSH_STATE_CLOSED
11468 || ssh->state == SSH_STATE_PREPACKET) return;
11469 if (ssh->version == 1) {
11470 logevent("Unable to send BREAK signal in SSH-1");
11471 } else if (ssh->mainchan) {
11472 pktout = ssh2_chanreq_init(ssh->mainchan, "break", NULL, NULL);
11473 ssh2_pkt_adduint32(pktout, 0); /* default break length */
11474 ssh2_pkt_send(ssh, pktout);
11477 /* Is is a POSIX signal? */
11478 const char *signame = NULL;
11479 if (code == TS_SIGABRT) signame = "ABRT";
11480 if (code == TS_SIGALRM) signame = "ALRM";
11481 if (code == TS_SIGFPE) signame = "FPE";
11482 if (code == TS_SIGHUP) signame = "HUP";
11483 if (code == TS_SIGILL) signame = "ILL";
11484 if (code == TS_SIGINT) signame = "INT";
11485 if (code == TS_SIGKILL) signame = "KILL";
11486 if (code == TS_SIGPIPE) signame = "PIPE";
11487 if (code == TS_SIGQUIT) signame = "QUIT";
11488 if (code == TS_SIGSEGV) signame = "SEGV";
11489 if (code == TS_SIGTERM) signame = "TERM";
11490 if (code == TS_SIGUSR1) signame = "USR1";
11491 if (code == TS_SIGUSR2) signame = "USR2";
11492 /* The SSH-2 protocol does in principle support arbitrary named
11493 * signals, including signame@domain, but we don't support those. */
11495 /* It's a signal. */
11496 if (ssh->version == 2 && ssh->mainchan) {
11497 pktout = ssh2_chanreq_init(ssh->mainchan, "signal", NULL, NULL);
11498 ssh2_pkt_addstring(pktout, signame);
11499 ssh2_pkt_send(ssh, pktout);
11500 logeventf(ssh, "Sent signal SIG%s", signame);
11503 /* Never heard of it. Do nothing */
11508 void *new_sock_channel(void *handle, struct PortForwarding *pf)
11510 Ssh ssh = (Ssh) handle;
11511 struct ssh_channel *c;
11512 c = snew(struct ssh_channel);
11515 ssh2_channel_init(c);
11516 c->halfopen = TRUE;
11517 c->type = CHAN_SOCKDATA_DORMANT;/* identify channel type */
11519 add234(ssh->channels, c);
11523 unsigned ssh_alloc_sharing_channel(Ssh ssh, void *sharing_ctx)
11525 struct ssh_channel *c;
11526 c = snew(struct ssh_channel);
11529 ssh2_channel_init(c);
11530 c->type = CHAN_SHARING;
11531 c->u.sharing.ctx = sharing_ctx;
11532 add234(ssh->channels, c);
11536 void ssh_delete_sharing_channel(Ssh ssh, unsigned localid)
11538 struct ssh_channel *c;
11540 c = find234(ssh->channels, &localid, ssh_channelfind);
11542 ssh_channel_destroy(c);
11545 void ssh_send_packet_from_downstream(Ssh ssh, unsigned id, int type,
11546 const void *data, int datalen,
11547 const char *additional_log_text)
11549 struct Packet *pkt;
11551 pkt = ssh2_pkt_init(type);
11552 pkt->downstream_id = id;
11553 pkt->additional_log_text = additional_log_text;
11554 ssh2_pkt_adddata(pkt, data, datalen);
11555 ssh2_pkt_send(ssh, pkt);
11559 * This is called when stdout/stderr (the entity to which
11560 * from_backend sends data) manages to clear some backlog.
11562 static void ssh_unthrottle(void *handle, int bufsize)
11564 Ssh ssh = (Ssh) handle;
11567 if (ssh->version == 1) {
11568 if (ssh->v1_stdout_throttling && bufsize < SSH1_BUFFER_LIMIT) {
11569 ssh->v1_stdout_throttling = 0;
11570 ssh_throttle_conn(ssh, -1);
11573 if (ssh->mainchan) {
11574 ssh2_set_window(ssh->mainchan,
11575 bufsize < ssh->mainchan->v.v2.locmaxwin ?
11576 ssh->mainchan->v.v2.locmaxwin - bufsize : 0);
11577 if (ssh_is_simple(ssh))
11580 buflimit = ssh->mainchan->v.v2.locmaxwin;
11581 if (ssh->mainchan->throttling_conn && bufsize <= buflimit) {
11582 ssh->mainchan->throttling_conn = 0;
11583 ssh_throttle_conn(ssh, -1);
11589 * Now process any SSH connection data that was stashed in our
11590 * queue while we were frozen.
11592 ssh_process_queued_incoming_data(ssh);
11595 void ssh_send_port_open(void *channel, const char *hostname, int port,
11598 struct ssh_channel *c = (struct ssh_channel *)channel;
11600 struct Packet *pktout;
11602 logeventf(ssh, "Opening connection to %s:%d for %s", hostname, port, org);
11604 if (ssh->version == 1) {
11605 send_packet(ssh, SSH1_MSG_PORT_OPEN,
11606 PKT_INT, c->localid,
11609 /* PKT_STR, <org:orgport>, */
11612 pktout = ssh2_chanopen_init(c, "direct-tcpip");
11614 char *trimmed_host = host_strduptrim(hostname);
11615 ssh2_pkt_addstring(pktout, trimmed_host);
11616 sfree(trimmed_host);
11618 ssh2_pkt_adduint32(pktout, port);
11620 * We make up values for the originator data; partly it's
11621 * too much hassle to keep track, and partly I'm not
11622 * convinced the server should be told details like that
11623 * about my local network configuration.
11624 * The "originator IP address" is syntactically a numeric
11625 * IP address, and some servers (e.g., Tectia) get upset
11626 * if it doesn't match this syntax.
11628 ssh2_pkt_addstring(pktout, "0.0.0.0");
11629 ssh2_pkt_adduint32(pktout, 0);
11630 ssh2_pkt_send(ssh, pktout);
11634 static int ssh_connected(void *handle)
11636 Ssh ssh = (Ssh) handle;
11637 return ssh->s != NULL;
11640 static int ssh_sendok(void *handle)
11642 Ssh ssh = (Ssh) handle;
11643 return ssh->send_ok;
11646 static int ssh_ldisc(void *handle, int option)
11648 Ssh ssh = (Ssh) handle;
11649 if (option == LD_ECHO)
11650 return ssh->echoing;
11651 if (option == LD_EDIT)
11652 return ssh->editing;
11656 static void ssh_provide_ldisc(void *handle, void *ldisc)
11658 Ssh ssh = (Ssh) handle;
11659 ssh->ldisc = ldisc;
11662 static void ssh_provide_logctx(void *handle, void *logctx)
11664 Ssh ssh = (Ssh) handle;
11665 ssh->logctx = logctx;
11668 static int ssh_return_exitcode(void *handle)
11670 Ssh ssh = (Ssh) handle;
11671 if (ssh->s != NULL)
11674 return (ssh->exitcode >= 0 ? ssh->exitcode : INT_MAX);
11678 * cfg_info for SSH is the protocol running in this session.
11679 * (1 or 2 for the full SSH-1 or SSH-2 protocol; -1 for the bare
11680 * SSH-2 connection protocol, i.e. a downstream; 0 for not-decided-yet.)
11682 static int ssh_cfg_info(void *handle)
11684 Ssh ssh = (Ssh) handle;
11685 if (ssh->version == 0)
11686 return 0; /* don't know yet */
11687 else if (ssh->bare_connection)
11690 return ssh->version;
11694 * Gross hack: pscp will try to start SFTP but fall back to scp1 if
11695 * that fails. This variable is the means by which scp.c can reach
11696 * into the SSH code and find out which one it got.
11698 extern int ssh_fallback_cmd(void *handle)
11700 Ssh ssh = (Ssh) handle;
11701 return ssh->fallback_cmd;
11704 Backend ssh_backend = {
11714 ssh_return_exitcode,
11718 ssh_provide_logctx,
11721 ssh_test_for_upstream,