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 #define logevent(s) logevent(ssh->frontend, s)
961 /* logevent, only printf-formatted. */
962 static void logeventf(Ssh ssh, const char *fmt, ...)
968 buf = dupvprintf(fmt, ap);
974 static void bomb_out(Ssh ssh, char *text)
976 ssh_do_close(ssh, FALSE);
978 connection_fatal(ssh->frontend, "%s", text);
982 #define bombout(msg) bomb_out(ssh, dupprintf msg)
984 /* Helper function for common bits of parsing ttymodes. */
985 static void parse_ttymodes(Ssh ssh,
986 void (*do_mode)(void *data, char *mode, char *val),
991 for (val = conf_get_str_strs(ssh->conf, CONF_ttymodes, NULL, &key);
993 val = conf_get_str_strs(ssh->conf, CONF_ttymodes, key, &key)) {
995 * val[0] is either 'V', indicating that an explicit value
996 * follows it, or 'A' indicating that we should pass the
997 * value through from the local environment via get_ttymode.
1000 val = get_ttymode(ssh->frontend, key);
1002 do_mode(data, key, val);
1006 do_mode(data, key, val + 1); /* skip the 'V' */
1010 static int ssh_channelcmp(void *av, void *bv)
1012 struct ssh_channel *a = (struct ssh_channel *) av;
1013 struct ssh_channel *b = (struct ssh_channel *) bv;
1014 if (a->localid < b->localid)
1016 if (a->localid > b->localid)
1020 static int ssh_channelfind(void *av, void *bv)
1022 unsigned *a = (unsigned *) av;
1023 struct ssh_channel *b = (struct ssh_channel *) bv;
1024 if (*a < b->localid)
1026 if (*a > b->localid)
1031 static int ssh_rportcmp_ssh1(void *av, void *bv)
1033 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
1034 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
1036 if ( (i = strcmp(a->dhost, b->dhost)) != 0)
1037 return i < 0 ? -1 : +1;
1038 if (a->dport > b->dport)
1040 if (a->dport < b->dport)
1045 static int ssh_rportcmp_ssh2(void *av, void *bv)
1047 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
1048 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
1050 if ( (i = strcmp(a->shost, b->shost)) != 0)
1051 return i < 0 ? -1 : +1;
1052 if (a->sport > b->sport)
1054 if (a->sport < b->sport)
1060 * Special form of strcmp which can cope with NULL inputs. NULL is
1061 * defined to sort before even the empty string.
1063 static int nullstrcmp(const char *a, const char *b)
1065 if (a == NULL && b == NULL)
1071 return strcmp(a, b);
1074 static int ssh_portcmp(void *av, void *bv)
1076 struct ssh_portfwd *a = (struct ssh_portfwd *) av;
1077 struct ssh_portfwd *b = (struct ssh_portfwd *) bv;
1079 if (a->type > b->type)
1081 if (a->type < b->type)
1083 if (a->addressfamily > b->addressfamily)
1085 if (a->addressfamily < b->addressfamily)
1087 if ( (i = nullstrcmp(a->saddr, b->saddr)) != 0)
1088 return i < 0 ? -1 : +1;
1089 if (a->sport > b->sport)
1091 if (a->sport < b->sport)
1093 if (a->type != 'D') {
1094 if ( (i = nullstrcmp(a->daddr, b->daddr)) != 0)
1095 return i < 0 ? -1 : +1;
1096 if (a->dport > b->dport)
1098 if (a->dport < b->dport)
1104 static int alloc_channel_id(Ssh ssh)
1106 const unsigned CHANNEL_NUMBER_OFFSET = 256;
1107 unsigned low, high, mid;
1109 struct ssh_channel *c;
1112 * First-fit allocation of channel numbers: always pick the
1113 * lowest unused one. To do this, binary-search using the
1114 * counted B-tree to find the largest channel ID which is in a
1115 * contiguous sequence from the beginning. (Precisely
1116 * everything in that sequence must have ID equal to its tree
1117 * index plus CHANNEL_NUMBER_OFFSET.)
1119 tsize = count234(ssh->channels);
1123 while (high - low > 1) {
1124 mid = (high + low) / 2;
1125 c = index234(ssh->channels, mid);
1126 if (c->localid == mid + CHANNEL_NUMBER_OFFSET)
1127 low = mid; /* this one is fine */
1129 high = mid; /* this one is past it */
1132 * Now low points to either -1, or the tree index of the
1133 * largest ID in the initial sequence.
1136 unsigned i = low + 1 + CHANNEL_NUMBER_OFFSET;
1137 assert(NULL == find234(ssh->channels, &i, ssh_channelfind));
1139 return low + 1 + CHANNEL_NUMBER_OFFSET;
1142 static void c_write_stderr(int trusted, const char *buf, int len)
1145 for (i = 0; i < len; i++)
1146 if (buf[i] != '\r' && (trusted || buf[i] == '\n' || (buf[i] & 0x60)))
1147 fputc(buf[i], stderr);
1150 static void c_write(Ssh ssh, const char *buf, int len)
1152 if (flags & FLAG_STDERR)
1153 c_write_stderr(1, buf, len);
1155 from_backend(ssh->frontend, 1, buf, len);
1158 static void c_write_untrusted(Ssh ssh, const char *buf, int len)
1160 if (flags & FLAG_STDERR)
1161 c_write_stderr(0, buf, len);
1163 from_backend_untrusted(ssh->frontend, buf, len);
1166 static void c_write_str(Ssh ssh, const char *buf)
1168 c_write(ssh, buf, strlen(buf));
1171 static void ssh_free_packet(struct Packet *pkt)
1176 static struct Packet *ssh_new_packet(void)
1178 struct Packet *pkt = snew(struct Packet);
1180 pkt->body = pkt->data = NULL;
1186 static void ssh1_log_incoming_packet(Ssh ssh, struct Packet *pkt)
1189 struct logblank_t blanks[4];
1195 if (ssh->logomitdata &&
1196 (pkt->type == SSH1_SMSG_STDOUT_DATA ||
1197 pkt->type == SSH1_SMSG_STDERR_DATA ||
1198 pkt->type == SSH1_MSG_CHANNEL_DATA)) {
1199 /* "Session data" packets - omit the data string. */
1200 if (pkt->type == SSH1_MSG_CHANNEL_DATA)
1201 ssh_pkt_getuint32(pkt); /* skip channel id */
1202 blanks[nblanks].offset = pkt->savedpos + 4;
1203 blanks[nblanks].type = PKTLOG_OMIT;
1204 ssh_pkt_getstring(pkt, &str, &slen);
1206 blanks[nblanks].len = slen;
1210 log_packet(ssh->logctx, PKT_INCOMING, pkt->type,
1211 ssh1_pkt_type(pkt->type),
1212 pkt->body, pkt->length, nblanks, blanks, NULL,
1216 static void ssh1_log_outgoing_packet(Ssh ssh, struct Packet *pkt)
1219 struct logblank_t blanks[4];
1224 * For outgoing packets, pkt->length represents the length of the
1225 * whole packet starting at pkt->data (including some header), and
1226 * pkt->body refers to the point within that where the log-worthy
1227 * payload begins. However, incoming packets expect pkt->length to
1228 * represent only the payload length (that is, it's measured from
1229 * pkt->body not from pkt->data). Temporarily adjust our outgoing
1230 * packet to conform to the incoming-packet semantics, so that we
1231 * can analyse it with the ssh_pkt_get functions.
1233 pkt->length -= (pkt->body - pkt->data);
1236 if (ssh->logomitdata &&
1237 (pkt->type == SSH1_CMSG_STDIN_DATA ||
1238 pkt->type == SSH1_MSG_CHANNEL_DATA)) {
1239 /* "Session data" packets - omit the data string. */
1240 if (pkt->type == SSH1_MSG_CHANNEL_DATA)
1241 ssh_pkt_getuint32(pkt); /* skip channel id */
1242 blanks[nblanks].offset = pkt->savedpos + 4;
1243 blanks[nblanks].type = PKTLOG_OMIT;
1244 ssh_pkt_getstring(pkt, &str, &slen);
1246 blanks[nblanks].len = slen;
1251 if ((pkt->type == SSH1_CMSG_AUTH_PASSWORD ||
1252 pkt->type == SSH1_CMSG_AUTH_TIS_RESPONSE ||
1253 pkt->type == SSH1_CMSG_AUTH_CCARD_RESPONSE) &&
1254 conf_get_int(ssh->conf, CONF_logomitpass)) {
1255 /* If this is a password or similar packet, blank the password(s). */
1256 blanks[nblanks].offset = 0;
1257 blanks[nblanks].len = pkt->length;
1258 blanks[nblanks].type = PKTLOG_BLANK;
1260 } else if (pkt->type == SSH1_CMSG_X11_REQUEST_FORWARDING &&
1261 conf_get_int(ssh->conf, CONF_logomitpass)) {
1263 * If this is an X forwarding request packet, blank the fake
1266 * Note that while we blank the X authentication data here, we
1267 * don't take any special action to blank the start of an X11
1268 * channel, so using MIT-MAGIC-COOKIE-1 and actually opening
1269 * an X connection without having session blanking enabled is
1270 * likely to leak your cookie into the log.
1273 ssh_pkt_getstring(pkt, &str, &slen);
1274 blanks[nblanks].offset = pkt->savedpos;
1275 blanks[nblanks].type = PKTLOG_BLANK;
1276 ssh_pkt_getstring(pkt, &str, &slen);
1278 blanks[nblanks].len = pkt->savedpos - blanks[nblanks].offset;
1283 log_packet(ssh->logctx, PKT_OUTGOING, pkt->data[12],
1284 ssh1_pkt_type(pkt->data[12]),
1285 pkt->body, pkt->length,
1286 nblanks, blanks, NULL, 0, NULL);
1289 * Undo the above adjustment of pkt->length, to put the packet
1290 * back in the state we found it.
1292 pkt->length += (pkt->body - pkt->data);
1296 * Collect incoming data in the incoming packet buffer.
1297 * Decipher and verify the packet when it is completely read.
1298 * Drop SSH1_MSG_DEBUG and SSH1_MSG_IGNORE packets.
1299 * Update the *data and *datalen variables.
1300 * Return a Packet structure when a packet is completed.
1302 static struct Packet *ssh1_rdpkt(Ssh ssh, const unsigned char **data,
1305 struct rdpkt1_state_tag *st = &ssh->rdpkt1_state;
1307 crBegin(ssh->ssh1_rdpkt_crstate);
1309 st->pktin = ssh_new_packet();
1311 st->pktin->type = 0;
1312 st->pktin->length = 0;
1314 for (st->i = st->len = 0; st->i < 4; st->i++) {
1315 while ((*datalen) == 0)
1317 st->len = (st->len << 8) + **data;
1318 (*data)++, (*datalen)--;
1321 st->pad = 8 - (st->len % 8);
1322 st->biglen = st->len + st->pad;
1323 st->pktin->length = st->len - 5;
1325 if (st->biglen < 0) {
1326 bombout(("Extremely large packet length from server suggests"
1327 " data stream corruption"));
1328 ssh_free_packet(st->pktin);
1332 st->pktin->maxlen = st->biglen;
1333 st->pktin->data = snewn(st->biglen + APIEXTRA, unsigned char);
1335 st->to_read = st->biglen;
1336 st->p = st->pktin->data;
1337 while (st->to_read > 0) {
1338 st->chunk = st->to_read;
1339 while ((*datalen) == 0)
1341 if (st->chunk > (*datalen))
1342 st->chunk = (*datalen);
1343 memcpy(st->p, *data, st->chunk);
1345 *datalen -= st->chunk;
1347 st->to_read -= st->chunk;
1350 if (ssh->cipher && detect_attack(ssh->crcda_ctx, st->pktin->data,
1351 st->biglen, NULL)) {
1352 bombout(("Network attack (CRC compensation) detected!"));
1353 ssh_free_packet(st->pktin);
1358 ssh->cipher->decrypt(ssh->v1_cipher_ctx, st->pktin->data, st->biglen);
1360 st->realcrc = crc32_compute(st->pktin->data, st->biglen - 4);
1361 st->gotcrc = GET_32BIT(st->pktin->data + st->biglen - 4);
1362 if (st->gotcrc != st->realcrc) {
1363 bombout(("Incorrect CRC received on packet"));
1364 ssh_free_packet(st->pktin);
1368 st->pktin->body = st->pktin->data + st->pad + 1;
1370 if (ssh->v1_compressing) {
1371 unsigned char *decompblk;
1373 if (!zlib_decompress_block(ssh->sc_comp_ctx,
1374 st->pktin->body - 1, st->pktin->length + 1,
1375 &decompblk, &decomplen)) {
1376 bombout(("Zlib decompression encountered invalid data"));
1377 ssh_free_packet(st->pktin);
1381 if (st->pktin->maxlen < st->pad + decomplen) {
1382 st->pktin->maxlen = st->pad + decomplen;
1383 st->pktin->data = sresize(st->pktin->data,
1384 st->pktin->maxlen + APIEXTRA,
1386 st->pktin->body = st->pktin->data + st->pad + 1;
1389 memcpy(st->pktin->body - 1, decompblk, decomplen);
1391 st->pktin->length = decomplen - 1;
1394 st->pktin->type = st->pktin->body[-1];
1397 * Now pktin->body and pktin->length identify the semantic content
1398 * of the packet, excluding the initial type byte.
1402 ssh1_log_incoming_packet(ssh, st->pktin);
1404 st->pktin->savedpos = 0;
1406 crFinish(st->pktin);
1409 static void ssh2_log_incoming_packet(Ssh ssh, struct Packet *pkt)
1412 struct logblank_t blanks[4];
1418 if (ssh->logomitdata &&
1419 (pkt->type == SSH2_MSG_CHANNEL_DATA ||
1420 pkt->type == SSH2_MSG_CHANNEL_EXTENDED_DATA)) {
1421 /* "Session data" packets - omit the data string. */
1422 ssh_pkt_getuint32(pkt); /* skip channel id */
1423 if (pkt->type == SSH2_MSG_CHANNEL_EXTENDED_DATA)
1424 ssh_pkt_getuint32(pkt); /* skip extended data type */
1425 blanks[nblanks].offset = pkt->savedpos + 4;
1426 blanks[nblanks].type = PKTLOG_OMIT;
1427 ssh_pkt_getstring(pkt, &str, &slen);
1429 blanks[nblanks].len = slen;
1434 log_packet(ssh->logctx, PKT_INCOMING, pkt->type,
1435 ssh2_pkt_type(ssh->pkt_kctx, ssh->pkt_actx, pkt->type),
1436 pkt->body, pkt->length, nblanks, blanks, &pkt->sequence,
1440 static void ssh2_log_outgoing_packet(Ssh ssh, struct Packet *pkt)
1443 struct logblank_t blanks[4];
1448 * For outgoing packets, pkt->length represents the length of the
1449 * whole packet starting at pkt->data (including some header), and
1450 * pkt->body refers to the point within that where the log-worthy
1451 * payload begins. However, incoming packets expect pkt->length to
1452 * represent only the payload length (that is, it's measured from
1453 * pkt->body not from pkt->data). Temporarily adjust our outgoing
1454 * packet to conform to the incoming-packet semantics, so that we
1455 * can analyse it with the ssh_pkt_get functions.
1457 pkt->length -= (pkt->body - pkt->data);
1460 if (ssh->logomitdata &&
1461 (pkt->type == SSH2_MSG_CHANNEL_DATA ||
1462 pkt->type == SSH2_MSG_CHANNEL_EXTENDED_DATA)) {
1463 /* "Session data" packets - omit the data string. */
1464 ssh_pkt_getuint32(pkt); /* skip channel id */
1465 if (pkt->type == SSH2_MSG_CHANNEL_EXTENDED_DATA)
1466 ssh_pkt_getuint32(pkt); /* skip extended data type */
1467 blanks[nblanks].offset = pkt->savedpos + 4;
1468 blanks[nblanks].type = PKTLOG_OMIT;
1469 ssh_pkt_getstring(pkt, &str, &slen);
1471 blanks[nblanks].len = slen;
1476 if (pkt->type == SSH2_MSG_USERAUTH_REQUEST &&
1477 conf_get_int(ssh->conf, CONF_logomitpass)) {
1478 /* If this is a password packet, blank the password(s). */
1480 ssh_pkt_getstring(pkt, &str, &slen);
1481 ssh_pkt_getstring(pkt, &str, &slen);
1482 ssh_pkt_getstring(pkt, &str, &slen);
1483 if (slen == 8 && !memcmp(str, "password", 8)) {
1484 ssh2_pkt_getbool(pkt);
1485 /* Blank the password field. */
1486 blanks[nblanks].offset = pkt->savedpos;
1487 blanks[nblanks].type = PKTLOG_BLANK;
1488 ssh_pkt_getstring(pkt, &str, &slen);
1490 blanks[nblanks].len = pkt->savedpos - blanks[nblanks].offset;
1492 /* If there's another password field beyond it (change of
1493 * password), blank that too. */
1494 ssh_pkt_getstring(pkt, &str, &slen);
1496 blanks[nblanks-1].len =
1497 pkt->savedpos - blanks[nblanks].offset;
1500 } else if (ssh->pkt_actx == SSH2_PKTCTX_KBDINTER &&
1501 pkt->type == SSH2_MSG_USERAUTH_INFO_RESPONSE &&
1502 conf_get_int(ssh->conf, CONF_logomitpass)) {
1503 /* If this is a keyboard-interactive response packet, blank
1506 ssh_pkt_getuint32(pkt);
1507 blanks[nblanks].offset = pkt->savedpos;
1508 blanks[nblanks].type = PKTLOG_BLANK;
1510 ssh_pkt_getstring(pkt, &str, &slen);
1514 blanks[nblanks].len = pkt->savedpos - blanks[nblanks].offset;
1516 } else if (pkt->type == SSH2_MSG_CHANNEL_REQUEST &&
1517 conf_get_int(ssh->conf, CONF_logomitpass)) {
1519 * If this is an X forwarding request packet, blank the fake
1522 * Note that while we blank the X authentication data here, we
1523 * don't take any special action to blank the start of an X11
1524 * channel, so using MIT-MAGIC-COOKIE-1 and actually opening
1525 * an X connection without having session blanking enabled is
1526 * likely to leak your cookie into the log.
1529 ssh_pkt_getuint32(pkt);
1530 ssh_pkt_getstring(pkt, &str, &slen);
1531 if (slen == 7 && !memcmp(str, "x11-req", 0)) {
1532 ssh2_pkt_getbool(pkt);
1533 ssh2_pkt_getbool(pkt);
1534 ssh_pkt_getstring(pkt, &str, &slen);
1535 blanks[nblanks].offset = pkt->savedpos;
1536 blanks[nblanks].type = PKTLOG_BLANK;
1537 ssh_pkt_getstring(pkt, &str, &slen);
1539 blanks[nblanks].len = pkt->savedpos - blanks[nblanks].offset;
1545 log_packet(ssh->logctx, PKT_OUTGOING, pkt->data[5],
1546 ssh2_pkt_type(ssh->pkt_kctx, ssh->pkt_actx, pkt->data[5]),
1547 pkt->body, pkt->length, nblanks, blanks,
1548 &ssh->v2_outgoing_sequence,
1549 pkt->downstream_id, pkt->additional_log_text);
1552 * Undo the above adjustment of pkt->length, to put the packet
1553 * back in the state we found it.
1555 pkt->length += (pkt->body - pkt->data);
1558 static struct Packet *ssh2_rdpkt(Ssh ssh, const unsigned char **data,
1561 struct rdpkt2_state_tag *st = &ssh->rdpkt2_state;
1563 crBegin(ssh->ssh2_rdpkt_crstate);
1565 st->pktin = ssh_new_packet();
1567 st->pktin->type = 0;
1568 st->pktin->length = 0;
1570 st->cipherblk = ssh->sccipher->blksize;
1573 if (st->cipherblk < 8)
1575 st->maclen = ssh->scmac ? ssh->scmac->len : 0;
1577 if (ssh->sccipher && (ssh->sccipher->flags & SSH_CIPHER_IS_CBC) &&
1578 ssh->scmac && !ssh->scmac_etm) {
1580 * When dealing with a CBC-mode cipher, we want to avoid the
1581 * possibility of an attacker's tweaking the ciphertext stream
1582 * so as to cause us to feed the same block to the block
1583 * cipher more than once and thus leak information
1584 * (VU#958563). The way we do this is not to take any
1585 * decisions on the basis of anything we've decrypted until
1586 * we've verified it with a MAC. That includes the packet
1587 * length, so we just read data and check the MAC repeatedly,
1588 * and when the MAC passes, see if the length we've got is
1591 * This defence is unnecessary in OpenSSH ETM mode, because
1592 * the whole point of ETM mode is that the attacker can't
1593 * tweak the ciphertext stream at all without the MAC
1594 * detecting it before we decrypt anything.
1597 /* May as well allocate the whole lot now. */
1598 st->pktin->data = snewn(OUR_V2_PACKETLIMIT + st->maclen + APIEXTRA,
1601 /* Read an amount corresponding to the MAC. */
1602 for (st->i = 0; st->i < st->maclen; st->i++) {
1603 while ((*datalen) == 0)
1605 st->pktin->data[st->i] = *(*data)++;
1611 unsigned char seq[4];
1612 ssh->scmac->start(ssh->sc_mac_ctx);
1613 PUT_32BIT(seq, st->incoming_sequence);
1614 ssh->scmac->bytes(ssh->sc_mac_ctx, seq, 4);
1617 for (;;) { /* Once around this loop per cipher block. */
1618 /* Read another cipher-block's worth, and tack it onto the end. */
1619 for (st->i = 0; st->i < st->cipherblk; st->i++) {
1620 while ((*datalen) == 0)
1622 st->pktin->data[st->packetlen+st->maclen+st->i] = *(*data)++;
1625 /* Decrypt one more block (a little further back in the stream). */
1626 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
1627 st->pktin->data + st->packetlen,
1629 /* Feed that block to the MAC. */
1630 ssh->scmac->bytes(ssh->sc_mac_ctx,
1631 st->pktin->data + st->packetlen, st->cipherblk);
1632 st->packetlen += st->cipherblk;
1633 /* See if that gives us a valid packet. */
1634 if (ssh->scmac->verresult(ssh->sc_mac_ctx,
1635 st->pktin->data + st->packetlen) &&
1636 ((st->len = toint(GET_32BIT(st->pktin->data))) ==
1639 if (st->packetlen >= OUR_V2_PACKETLIMIT) {
1640 bombout(("No valid incoming packet found"));
1641 ssh_free_packet(st->pktin);
1645 st->pktin->maxlen = st->packetlen + st->maclen;
1646 st->pktin->data = sresize(st->pktin->data,
1647 st->pktin->maxlen + APIEXTRA,
1649 } else if (ssh->scmac && ssh->scmac_etm) {
1650 st->pktin->data = snewn(4 + APIEXTRA, unsigned char);
1653 * OpenSSH encrypt-then-MAC mode: the packet length is
1654 * unencrypted, unless the cipher supports length encryption.
1656 for (st->i = st->len = 0; st->i < 4; st->i++) {
1657 while ((*datalen) == 0)
1659 st->pktin->data[st->i] = *(*data)++;
1662 /* Cipher supports length decryption, so do it */
1663 if (ssh->sccipher && (ssh->sccipher->flags & SSH_CIPHER_SEPARATE_LENGTH)) {
1664 /* Keep the packet the same though, so the MAC passes */
1665 unsigned char len[4];
1666 memcpy(len, st->pktin->data, 4);
1667 ssh->sccipher->decrypt_length(ssh->sc_cipher_ctx, len, 4, st->incoming_sequence);
1668 st->len = toint(GET_32BIT(len));
1670 st->len = toint(GET_32BIT(st->pktin->data));
1674 * _Completely_ silly lengths should be stomped on before they
1675 * do us any more damage.
1677 if (st->len < 0 || st->len > OUR_V2_PACKETLIMIT ||
1678 st->len % st->cipherblk != 0) {
1679 bombout(("Incoming packet length field was garbled"));
1680 ssh_free_packet(st->pktin);
1685 * So now we can work out the total packet length.
1687 st->packetlen = st->len + 4;
1690 * Allocate memory for the rest of the packet.
1692 st->pktin->maxlen = st->packetlen + st->maclen;
1693 st->pktin->data = sresize(st->pktin->data,
1694 st->pktin->maxlen + APIEXTRA,
1698 * Read the remainder of the packet.
1700 for (st->i = 4; st->i < st->packetlen + st->maclen; st->i++) {
1701 while ((*datalen) == 0)
1703 st->pktin->data[st->i] = *(*data)++;
1711 && !ssh->scmac->verify(ssh->sc_mac_ctx, st->pktin->data,
1712 st->len + 4, st->incoming_sequence)) {
1713 bombout(("Incorrect MAC received on packet"));
1714 ssh_free_packet(st->pktin);
1718 /* Decrypt everything between the length field and the MAC. */
1720 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
1721 st->pktin->data + 4,
1724 st->pktin->data = snewn(st->cipherblk + APIEXTRA, unsigned char);
1727 * Acquire and decrypt the first block of the packet. This will
1728 * contain the length and padding details.
1730 for (st->i = st->len = 0; st->i < st->cipherblk; st->i++) {
1731 while ((*datalen) == 0)
1733 st->pktin->data[st->i] = *(*data)++;
1738 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
1739 st->pktin->data, st->cipherblk);
1742 * Now get the length figure.
1744 st->len = toint(GET_32BIT(st->pktin->data));
1747 * _Completely_ silly lengths should be stomped on before they
1748 * do us any more damage.
1750 if (st->len < 0 || st->len > OUR_V2_PACKETLIMIT ||
1751 (st->len + 4) % st->cipherblk != 0) {
1752 bombout(("Incoming packet was garbled on decryption"));
1753 ssh_free_packet(st->pktin);
1758 * So now we can work out the total packet length.
1760 st->packetlen = st->len + 4;
1763 * Allocate memory for the rest of the packet.
1765 st->pktin->maxlen = st->packetlen + st->maclen;
1766 st->pktin->data = sresize(st->pktin->data,
1767 st->pktin->maxlen + APIEXTRA,
1771 * Read and decrypt the remainder of the packet.
1773 for (st->i = st->cipherblk; st->i < st->packetlen + st->maclen;
1775 while ((*datalen) == 0)
1777 st->pktin->data[st->i] = *(*data)++;
1780 /* Decrypt everything _except_ the MAC. */
1782 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
1783 st->pktin->data + st->cipherblk,
1784 st->packetlen - st->cipherblk);
1790 && !ssh->scmac->verify(ssh->sc_mac_ctx, st->pktin->data,
1791 st->len + 4, st->incoming_sequence)) {
1792 bombout(("Incorrect MAC received on packet"));
1793 ssh_free_packet(st->pktin);
1797 /* Get and sanity-check the amount of random padding. */
1798 st->pad = st->pktin->data[4];
1799 if (st->pad < 4 || st->len - st->pad < 1) {
1800 bombout(("Invalid padding length on received packet"));
1801 ssh_free_packet(st->pktin);
1805 * This enables us to deduce the payload length.
1807 st->payload = st->len - st->pad - 1;
1809 st->pktin->length = st->payload + 5;
1810 st->pktin->encrypted_len = st->packetlen;
1812 st->pktin->sequence = st->incoming_sequence++;
1814 st->pktin->length = st->packetlen - st->pad;
1815 assert(st->pktin->length >= 0);
1818 * Decompress packet payload.
1821 unsigned char *newpayload;
1824 ssh->sccomp->decompress(ssh->sc_comp_ctx,
1825 st->pktin->data + 5, st->pktin->length - 5,
1826 &newpayload, &newlen)) {
1827 if (st->pktin->maxlen < newlen + 5) {
1828 st->pktin->maxlen = newlen + 5;
1829 st->pktin->data = sresize(st->pktin->data,
1830 st->pktin->maxlen + APIEXTRA,
1833 st->pktin->length = 5 + newlen;
1834 memcpy(st->pktin->data + 5, newpayload, newlen);
1840 * RFC 4253 doesn't explicitly say that completely empty packets
1841 * with no type byte are forbidden, so treat them as deserving
1842 * an SSH_MSG_UNIMPLEMENTED.
1844 if (st->pktin->length <= 5) { /* == 5 we hope, but robustness */
1845 ssh2_msg_something_unimplemented(ssh, st->pktin);
1849 * pktin->body and pktin->length should identify the semantic
1850 * content of the packet, excluding the initial type byte.
1852 st->pktin->type = st->pktin->data[5];
1853 st->pktin->body = st->pktin->data + 6;
1854 st->pktin->length -= 6;
1855 assert(st->pktin->length >= 0); /* one last double-check */
1858 ssh2_log_incoming_packet(ssh, st->pktin);
1860 st->pktin->savedpos = 0;
1862 crFinish(st->pktin);
1865 static struct Packet *ssh2_bare_connection_rdpkt(Ssh ssh,
1866 const unsigned char **data,
1869 struct rdpkt2_bare_state_tag *st = &ssh->rdpkt2_bare_state;
1871 crBegin(ssh->ssh2_bare_rdpkt_crstate);
1874 * Read the packet length field.
1876 for (st->i = 0; st->i < 4; st->i++) {
1877 while ((*datalen) == 0)
1879 st->length[st->i] = *(*data)++;
1883 st->packetlen = toint(GET_32BIT_MSB_FIRST(st->length));
1884 if (st->packetlen <= 0 || st->packetlen >= OUR_V2_PACKETLIMIT) {
1885 bombout(("Invalid packet length received"));
1889 st->pktin = ssh_new_packet();
1890 st->pktin->data = snewn(st->packetlen, unsigned char);
1892 st->pktin->encrypted_len = st->packetlen;
1894 st->pktin->sequence = st->incoming_sequence++;
1897 * Read the remainder of the packet.
1899 for (st->i = 0; st->i < st->packetlen; st->i++) {
1900 while ((*datalen) == 0)
1902 st->pktin->data[st->i] = *(*data)++;
1907 * pktin->body and pktin->length should identify the semantic
1908 * content of the packet, excluding the initial type byte.
1910 st->pktin->type = st->pktin->data[0];
1911 st->pktin->body = st->pktin->data + 1;
1912 st->pktin->length = st->packetlen - 1;
1915 * Log incoming packet, possibly omitting sensitive fields.
1918 ssh2_log_incoming_packet(ssh, st->pktin);
1920 st->pktin->savedpos = 0;
1922 crFinish(st->pktin);
1925 static int s_wrpkt_prepare(Ssh ssh, struct Packet *pkt, int *offset_p)
1927 int pad, biglen, i, pktoffs;
1931 * XXX various versions of SC (including 8.8.4) screw up the
1932 * register allocation in this function and use the same register
1933 * (D6) for len and as a temporary, with predictable results. The
1934 * following sledgehammer prevents this.
1941 ssh1_log_outgoing_packet(ssh, pkt);
1943 if (ssh->v1_compressing) {
1944 unsigned char *compblk;
1946 zlib_compress_block(ssh->cs_comp_ctx,
1947 pkt->data + 12, pkt->length - 12,
1948 &compblk, &complen);
1949 ssh_pkt_ensure(pkt, complen + 2); /* just in case it's got bigger */
1950 memcpy(pkt->data + 12, compblk, complen);
1952 pkt->length = complen + 12;
1955 ssh_pkt_ensure(pkt, pkt->length + 4); /* space for CRC */
1957 len = pkt->length - 4 - 8; /* len(type+data+CRC) */
1958 pad = 8 - (len % 8);
1960 biglen = len + pad; /* len(padding+type+data+CRC) */
1962 for (i = pktoffs; i < 4+8; i++)
1963 pkt->data[i] = random_byte();
1964 crc = crc32_compute(pkt->data + pktoffs + 4, biglen - 4); /* all ex len */
1965 PUT_32BIT(pkt->data + pktoffs + 4 + biglen - 4, crc);
1966 PUT_32BIT(pkt->data + pktoffs, len);
1969 ssh->cipher->encrypt(ssh->v1_cipher_ctx,
1970 pkt->data + pktoffs + 4, biglen);
1972 if (offset_p) *offset_p = pktoffs;
1973 return biglen + 4; /* len(length+padding+type+data+CRC) */
1976 static int s_write(Ssh ssh, void *data, int len)
1979 log_packet(ssh->logctx, PKT_OUTGOING, -1, NULL, data, len,
1980 0, NULL, NULL, 0, NULL);
1983 return sk_write(ssh->s, (char *)data, len);
1986 static void s_wrpkt(Ssh ssh, struct Packet *pkt)
1988 int len, backlog, offset;
1989 len = s_wrpkt_prepare(ssh, pkt, &offset);
1990 backlog = s_write(ssh, pkt->data + offset, len);
1991 if (backlog > SSH_MAX_BACKLOG)
1992 ssh_throttle_all(ssh, 1, backlog);
1993 ssh_free_packet(pkt);
1996 static void s_wrpkt_defer(Ssh ssh, struct Packet *pkt)
1999 len = s_wrpkt_prepare(ssh, pkt, &offset);
2000 if (ssh->deferred_len + len > ssh->deferred_size) {
2001 ssh->deferred_size = ssh->deferred_len + len + 128;
2002 ssh->deferred_send_data = sresize(ssh->deferred_send_data,
2006 memcpy(ssh->deferred_send_data + ssh->deferred_len,
2007 pkt->data + offset, len);
2008 ssh->deferred_len += len;
2009 ssh_free_packet(pkt);
2013 * Construct a SSH-1 packet with the specified contents.
2014 * (This all-at-once interface used to be the only one, but now SSH-1
2015 * packets can also be constructed incrementally.)
2017 static struct Packet *construct_packet(Ssh ssh, int pkttype, va_list ap)
2023 pkt = ssh1_pkt_init(pkttype);
2025 while ((argtype = va_arg(ap, int)) != PKT_END) {
2026 unsigned char *argp, argchar;
2028 unsigned long argint;
2031 /* Actual fields in the packet */
2033 argint = va_arg(ap, int);
2034 ssh_pkt_adduint32(pkt, argint);
2037 argchar = (unsigned char) va_arg(ap, int);
2038 ssh_pkt_addbyte(pkt, argchar);
2041 argp = va_arg(ap, unsigned char *);
2042 arglen = va_arg(ap, int);
2043 ssh_pkt_adddata(pkt, argp, arglen);
2046 sargp = va_arg(ap, char *);
2047 ssh_pkt_addstring(pkt, sargp);
2050 bn = va_arg(ap, Bignum);
2051 ssh1_pkt_addmp(pkt, bn);
2059 static void send_packet(Ssh ssh, int pkttype, ...)
2063 va_start(ap, pkttype);
2064 pkt = construct_packet(ssh, pkttype, ap);
2069 static void defer_packet(Ssh ssh, int pkttype, ...)
2073 va_start(ap, pkttype);
2074 pkt = construct_packet(ssh, pkttype, ap);
2076 s_wrpkt_defer(ssh, pkt);
2079 static int ssh_versioncmp(const char *a, const char *b)
2082 unsigned long av, bv;
2084 av = strtoul(a, &ae, 10);
2085 bv = strtoul(b, &be, 10);
2087 return (av < bv ? -1 : +1);
2092 av = strtoul(ae, &ae, 10);
2093 bv = strtoul(be, &be, 10);
2095 return (av < bv ? -1 : +1);
2100 * Utility routines for putting an SSH-protocol `string' and
2101 * `uint32' into a hash state.
2103 static void hash_string(const struct ssh_hash *h, void *s, void *str, int len)
2105 unsigned char lenblk[4];
2106 PUT_32BIT(lenblk, len);
2107 h->bytes(s, lenblk, 4);
2108 h->bytes(s, str, len);
2111 static void hash_uint32(const struct ssh_hash *h, void *s, unsigned i)
2113 unsigned char intblk[4];
2114 PUT_32BIT(intblk, i);
2115 h->bytes(s, intblk, 4);
2119 * Packet construction functions. Mostly shared between SSH-1 and SSH-2.
2121 static void ssh_pkt_ensure(struct Packet *pkt, int length)
2123 if (pkt->maxlen < length) {
2124 unsigned char *body = pkt->body;
2125 int offset = body ? body - pkt->data : 0;
2126 pkt->maxlen = length + 256;
2127 pkt->data = sresize(pkt->data, pkt->maxlen + APIEXTRA, unsigned char);
2128 if (body) pkt->body = pkt->data + offset;
2131 static void ssh_pkt_adddata(struct Packet *pkt, const void *data, int len)
2134 ssh_pkt_ensure(pkt, pkt->length);
2135 memcpy(pkt->data + pkt->length - len, data, len);
2137 static void ssh_pkt_addbyte(struct Packet *pkt, unsigned char byte)
2139 ssh_pkt_adddata(pkt, &byte, 1);
2141 static void ssh2_pkt_addbool(struct Packet *pkt, unsigned char value)
2143 ssh_pkt_adddata(pkt, &value, 1);
2145 static void ssh_pkt_adduint32(struct Packet *pkt, unsigned long value)
2148 PUT_32BIT(x, value);
2149 ssh_pkt_adddata(pkt, x, 4);
2151 static void ssh_pkt_addstring_start(struct Packet *pkt)
2153 ssh_pkt_adduint32(pkt, 0);
2154 pkt->savedpos = pkt->length;
2156 static void ssh_pkt_addstring_data(struct Packet *pkt, const char *data,
2159 ssh_pkt_adddata(pkt, data, len);
2160 PUT_32BIT(pkt->data + pkt->savedpos - 4, pkt->length - pkt->savedpos);
2162 static void ssh_pkt_addstring_str(struct Packet *pkt, const char *data)
2164 ssh_pkt_addstring_data(pkt, data, strlen(data));
2166 static void ssh_pkt_addstring(struct Packet *pkt, const char *data)
2168 ssh_pkt_addstring_start(pkt);
2169 ssh_pkt_addstring_str(pkt, data);
2171 static void ssh1_pkt_addmp(struct Packet *pkt, Bignum b)
2173 int len = ssh1_bignum_length(b);
2174 unsigned char *data = snewn(len, unsigned char);
2175 (void) ssh1_write_bignum(data, b);
2176 ssh_pkt_adddata(pkt, data, len);
2179 static unsigned char *ssh2_mpint_fmt(Bignum b, int *len)
2182 int i, n = (bignum_bitcount(b) + 7) / 8;
2183 p = snewn(n + 1, unsigned char);
2185 for (i = 1; i <= n; i++)
2186 p[i] = bignum_byte(b, n - i);
2188 while (i <= n && p[i] == 0 && (p[i + 1] & 0x80) == 0)
2190 memmove(p, p + i, n + 1 - i);
2194 static void ssh2_pkt_addmp(struct Packet *pkt, Bignum b)
2198 p = ssh2_mpint_fmt(b, &len);
2199 ssh_pkt_addstring_start(pkt);
2200 ssh_pkt_addstring_data(pkt, (char *)p, len);
2204 static struct Packet *ssh1_pkt_init(int pkt_type)
2206 struct Packet *pkt = ssh_new_packet();
2207 pkt->length = 4 + 8; /* space for length + max padding */
2208 ssh_pkt_addbyte(pkt, pkt_type);
2209 pkt->body = pkt->data + pkt->length;
2210 pkt->type = pkt_type;
2211 pkt->downstream_id = 0;
2212 pkt->additional_log_text = NULL;
2216 /* For legacy code (SSH-1 and -2 packet construction used to be separate) */
2217 #define ssh2_pkt_ensure(pkt, length) ssh_pkt_ensure(pkt, length)
2218 #define ssh2_pkt_adddata(pkt, data, len) ssh_pkt_adddata(pkt, data, len)
2219 #define ssh2_pkt_addbyte(pkt, byte) ssh_pkt_addbyte(pkt, byte)
2220 #define ssh2_pkt_adduint32(pkt, value) ssh_pkt_adduint32(pkt, value)
2221 #define ssh2_pkt_addstring_start(pkt) ssh_pkt_addstring_start(pkt)
2222 #define ssh2_pkt_addstring_str(pkt, data) ssh_pkt_addstring_str(pkt, data)
2223 #define ssh2_pkt_addstring_data(pkt, data, len) ssh_pkt_addstring_data(pkt, data, len)
2224 #define ssh2_pkt_addstring(pkt, data) ssh_pkt_addstring(pkt, data)
2226 static struct Packet *ssh2_pkt_init(int pkt_type)
2228 struct Packet *pkt = ssh_new_packet();
2229 pkt->length = 5; /* space for packet length + padding length */
2231 pkt->type = pkt_type;
2232 ssh_pkt_addbyte(pkt, (unsigned char) pkt_type);
2233 pkt->body = pkt->data + pkt->length; /* after packet type */
2234 pkt->downstream_id = 0;
2235 pkt->additional_log_text = NULL;
2240 * Construct an SSH-2 final-form packet: compress it, encrypt it,
2241 * put the MAC on it. Final packet, ready to be sent, is stored in
2242 * pkt->data. Total length is returned.
2244 static int ssh2_pkt_construct(Ssh ssh, struct Packet *pkt)
2246 int cipherblk, maclen, padding, unencrypted_prefix, i;
2249 ssh2_log_outgoing_packet(ssh, pkt);
2251 if (ssh->bare_connection) {
2253 * Trivial packet construction for the bare connection
2256 PUT_32BIT(pkt->data + 1, pkt->length - 5);
2257 pkt->body = pkt->data + 1;
2258 ssh->v2_outgoing_sequence++; /* only for diagnostics, really */
2259 return pkt->length - 1;
2263 * Compress packet payload.
2266 unsigned char *newpayload;
2269 ssh->cscomp->compress(ssh->cs_comp_ctx, pkt->data + 5,
2271 &newpayload, &newlen)) {
2273 ssh2_pkt_adddata(pkt, newpayload, newlen);
2279 * Add padding. At least four bytes, and must also bring total
2280 * length (minus MAC) up to a multiple of the block size.
2281 * If pkt->forcepad is set, make sure the packet is at least that size
2284 cipherblk = ssh->cscipher ? ssh->cscipher->blksize : 8; /* block size */
2285 cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */
2287 unencrypted_prefix = (ssh->csmac && ssh->csmac_etm) ? 4 : 0;
2288 if (pkt->length + padding < pkt->forcepad)
2289 padding = pkt->forcepad - pkt->length;
2291 (cipherblk - (pkt->length - unencrypted_prefix + padding) % cipherblk)
2293 assert(padding <= 255);
2294 maclen = ssh->csmac ? ssh->csmac->len : 0;
2295 ssh2_pkt_ensure(pkt, pkt->length + padding + maclen);
2296 pkt->data[4] = padding;
2297 for (i = 0; i < padding; i++)
2298 pkt->data[pkt->length + i] = random_byte();
2299 PUT_32BIT(pkt->data, pkt->length + padding - 4);
2301 /* Encrypt length if the scheme requires it */
2302 if (ssh->cscipher && (ssh->cscipher->flags & SSH_CIPHER_SEPARATE_LENGTH)) {
2303 ssh->cscipher->encrypt_length(ssh->cs_cipher_ctx, pkt->data, 4,
2304 ssh->v2_outgoing_sequence);
2307 if (ssh->csmac && ssh->csmac_etm) {
2309 * OpenSSH-defined encrypt-then-MAC protocol.
2312 ssh->cscipher->encrypt(ssh->cs_cipher_ctx,
2313 pkt->data + 4, pkt->length + padding - 4);
2314 ssh->csmac->generate(ssh->cs_mac_ctx, pkt->data,
2315 pkt->length + padding,
2316 ssh->v2_outgoing_sequence);
2319 * SSH-2 standard protocol.
2322 ssh->csmac->generate(ssh->cs_mac_ctx, pkt->data,
2323 pkt->length + padding,
2324 ssh->v2_outgoing_sequence);
2326 ssh->cscipher->encrypt(ssh->cs_cipher_ctx,
2327 pkt->data, pkt->length + padding);
2330 ssh->v2_outgoing_sequence++; /* whether or not we MACed */
2331 pkt->encrypted_len = pkt->length + padding;
2333 /* Ready-to-send packet starts at pkt->data. We return length. */
2334 pkt->body = pkt->data;
2335 return pkt->length + padding + maclen;
2339 * Routines called from the main SSH code to send packets. There
2340 * are quite a few of these, because we have two separate
2341 * mechanisms for delaying the sending of packets:
2343 * - In order to send an IGNORE message and a password message in
2344 * a single fixed-length blob, we require the ability to
2345 * concatenate the encrypted forms of those two packets _into_ a
2346 * single blob and then pass it to our <network.h> transport
2347 * layer in one go. Hence, there's a deferment mechanism which
2348 * works after packet encryption.
2350 * - In order to avoid sending any connection-layer messages
2351 * during repeat key exchange, we have to queue up any such
2352 * outgoing messages _before_ they are encrypted (and in
2353 * particular before they're allocated sequence numbers), and
2354 * then send them once we've finished.
2356 * I call these mechanisms `defer' and `queue' respectively, so as
2357 * to distinguish them reasonably easily.
2359 * The functions send_noqueue() and defer_noqueue() free the packet
2360 * structure they are passed. Every outgoing packet goes through
2361 * precisely one of these functions in its life; packets passed to
2362 * ssh2_pkt_send() or ssh2_pkt_defer() either go straight to one of
2363 * these or get queued, and then when the queue is later emptied
2364 * the packets are all passed to defer_noqueue().
2366 * When using a CBC-mode cipher, it's necessary to ensure that an
2367 * attacker can't provide data to be encrypted using an IV that they
2368 * know. We ensure this by prefixing each packet that might contain
2369 * user data with an SSH_MSG_IGNORE. This is done using the deferral
2370 * mechanism, so in this case send_noqueue() ends up redirecting to
2371 * defer_noqueue(). If you don't like this inefficiency, don't use
2375 static void ssh2_pkt_defer_noqueue(Ssh, struct Packet *, int);
2376 static void ssh_pkt_defersend(Ssh);
2379 * Send an SSH-2 packet immediately, without queuing or deferring.
2381 static void ssh2_pkt_send_noqueue(Ssh ssh, struct Packet *pkt)
2385 if (ssh->cscipher != NULL && (ssh->cscipher->flags & SSH_CIPHER_IS_CBC)) {
2386 /* We need to send two packets, so use the deferral mechanism. */
2387 ssh2_pkt_defer_noqueue(ssh, pkt, FALSE);
2388 ssh_pkt_defersend(ssh);
2391 len = ssh2_pkt_construct(ssh, pkt);
2392 backlog = s_write(ssh, pkt->body, len);
2393 if (backlog > SSH_MAX_BACKLOG)
2394 ssh_throttle_all(ssh, 1, backlog);
2396 ssh->outgoing_data_size += pkt->encrypted_len;
2397 if (!ssh->kex_in_progress &&
2398 !ssh->bare_connection &&
2399 ssh->max_data_size != 0 &&
2400 ssh->outgoing_data_size > ssh->max_data_size)
2401 do_ssh2_transport(ssh, "too much data sent", -1, NULL);
2403 ssh_free_packet(pkt);
2407 * Defer an SSH-2 packet.
2409 static void ssh2_pkt_defer_noqueue(Ssh ssh, struct Packet *pkt, int noignore)
2412 if (ssh->cscipher != NULL && (ssh->cscipher->flags & SSH_CIPHER_IS_CBC) &&
2413 ssh->deferred_len == 0 && !noignore &&
2414 !(ssh->remote_bugs & BUG_CHOKES_ON_SSH2_IGNORE)) {
2416 * Interpose an SSH_MSG_IGNORE to ensure that user data don't
2417 * get encrypted with a known IV.
2419 struct Packet *ipkt = ssh2_pkt_init(SSH2_MSG_IGNORE);
2420 ssh2_pkt_addstring_start(ipkt);
2421 ssh2_pkt_defer_noqueue(ssh, ipkt, TRUE);
2423 len = ssh2_pkt_construct(ssh, pkt);
2424 if (ssh->deferred_len + len > ssh->deferred_size) {
2425 ssh->deferred_size = ssh->deferred_len + len + 128;
2426 ssh->deferred_send_data = sresize(ssh->deferred_send_data,
2430 memcpy(ssh->deferred_send_data + ssh->deferred_len, pkt->body, len);
2431 ssh->deferred_len += len;
2432 ssh->deferred_data_size += pkt->encrypted_len;
2433 ssh_free_packet(pkt);
2437 * Queue an SSH-2 packet.
2439 static void ssh2_pkt_queue(Ssh ssh, struct Packet *pkt)
2441 assert(ssh->queueing);
2443 if (ssh->queuelen >= ssh->queuesize) {
2444 ssh->queuesize = ssh->queuelen + 32;
2445 ssh->queue = sresize(ssh->queue, ssh->queuesize, struct Packet *);
2448 ssh->queue[ssh->queuelen++] = pkt;
2452 * Either queue or send a packet, depending on whether queueing is
2455 static void ssh2_pkt_send(Ssh ssh, struct Packet *pkt)
2458 ssh2_pkt_queue(ssh, pkt);
2460 ssh2_pkt_send_noqueue(ssh, pkt);
2464 * Either queue or defer a packet, depending on whether queueing is
2467 static void ssh2_pkt_defer(Ssh ssh, struct Packet *pkt)
2470 ssh2_pkt_queue(ssh, pkt);
2472 ssh2_pkt_defer_noqueue(ssh, pkt, FALSE);
2476 * Send the whole deferred data block constructed by
2477 * ssh2_pkt_defer() or SSH-1's defer_packet().
2479 * The expected use of the defer mechanism is that you call
2480 * ssh2_pkt_defer() a few times, then call ssh_pkt_defersend(). If
2481 * not currently queueing, this simply sets up deferred_send_data
2482 * and then sends it. If we _are_ currently queueing, the calls to
2483 * ssh2_pkt_defer() put the deferred packets on to the queue
2484 * instead, and therefore ssh_pkt_defersend() has no deferred data
2485 * to send. Hence, there's no need to make it conditional on
2488 static void ssh_pkt_defersend(Ssh ssh)
2491 backlog = s_write(ssh, ssh->deferred_send_data, ssh->deferred_len);
2492 ssh->deferred_len = ssh->deferred_size = 0;
2493 sfree(ssh->deferred_send_data);
2494 ssh->deferred_send_data = NULL;
2495 if (backlog > SSH_MAX_BACKLOG)
2496 ssh_throttle_all(ssh, 1, backlog);
2498 ssh->outgoing_data_size += ssh->deferred_data_size;
2499 if (!ssh->kex_in_progress &&
2500 !ssh->bare_connection &&
2501 ssh->max_data_size != 0 &&
2502 ssh->outgoing_data_size > ssh->max_data_size)
2503 do_ssh2_transport(ssh, "too much data sent", -1, NULL);
2504 ssh->deferred_data_size = 0;
2508 * Send a packet whose length needs to be disguised (typically
2509 * passwords or keyboard-interactive responses).
2511 static void ssh2_pkt_send_with_padding(Ssh ssh, struct Packet *pkt,
2517 * The simplest way to do this is to adjust the
2518 * variable-length padding field in the outgoing packet.
2520 * Currently compiled out, because some Cisco SSH servers
2521 * don't like excessively padded packets (bah, why's it
2524 pkt->forcepad = padsize;
2525 ssh2_pkt_send(ssh, pkt);
2530 * If we can't do that, however, an alternative approach is
2531 * to use the pkt_defer mechanism to bundle the packet
2532 * tightly together with an SSH_MSG_IGNORE such that their
2533 * combined length is a constant. So first we construct the
2534 * final form of this packet and defer its sending.
2536 ssh2_pkt_defer(ssh, pkt);
2539 * Now construct an SSH_MSG_IGNORE which includes a string
2540 * that's an exact multiple of the cipher block size. (If
2541 * the cipher is NULL so that the block size is
2542 * unavailable, we don't do this trick at all, because we
2543 * gain nothing by it.)
2545 if (ssh->cscipher &&
2546 !(ssh->remote_bugs & BUG_CHOKES_ON_SSH2_IGNORE)) {
2549 stringlen = (256 - ssh->deferred_len);
2550 stringlen += ssh->cscipher->blksize - 1;
2551 stringlen -= (stringlen % ssh->cscipher->blksize);
2554 * Temporarily disable actual compression, so we
2555 * can guarantee to get this string exactly the
2556 * length we want it. The compression-disabling
2557 * routine should return an integer indicating how
2558 * many bytes we should adjust our string length
2562 ssh->cscomp->disable_compression(ssh->cs_comp_ctx);
2564 pkt = ssh2_pkt_init(SSH2_MSG_IGNORE);
2565 ssh2_pkt_addstring_start(pkt);
2566 for (i = 0; i < stringlen; i++) {
2567 char c = (char) random_byte();
2568 ssh2_pkt_addstring_data(pkt, &c, 1);
2570 ssh2_pkt_defer(ssh, pkt);
2572 ssh_pkt_defersend(ssh);
2577 * Send all queued SSH-2 packets. We send them by means of
2578 * ssh2_pkt_defer_noqueue(), in case they included a pair of
2579 * packets that needed to be lumped together.
2581 static void ssh2_pkt_queuesend(Ssh ssh)
2585 assert(!ssh->queueing);
2587 for (i = 0; i < ssh->queuelen; i++)
2588 ssh2_pkt_defer_noqueue(ssh, ssh->queue[i], FALSE);
2591 ssh_pkt_defersend(ssh);
2595 void bndebug(char *string, Bignum b)
2599 p = ssh2_mpint_fmt(b, &len);
2600 debug(("%s", string));
2601 for (i = 0; i < len; i++)
2602 debug((" %02x", p[i]));
2608 static void hash_mpint(const struct ssh_hash *h, void *s, Bignum b)
2612 p = ssh2_mpint_fmt(b, &len);
2613 hash_string(h, s, p, len);
2618 * Packet decode functions for both SSH-1 and SSH-2.
2620 static unsigned long ssh_pkt_getuint32(struct Packet *pkt)
2622 unsigned long value;
2623 if (pkt->length - pkt->savedpos < 4)
2624 return 0; /* arrgh, no way to decline (FIXME?) */
2625 value = GET_32BIT(pkt->body + pkt->savedpos);
2629 static int ssh2_pkt_getbool(struct Packet *pkt)
2631 unsigned long value;
2632 if (pkt->length - pkt->savedpos < 1)
2633 return 0; /* arrgh, no way to decline (FIXME?) */
2634 value = pkt->body[pkt->savedpos] != 0;
2638 static void ssh_pkt_getstring(struct Packet *pkt, char **p, int *length)
2643 if (pkt->length - pkt->savedpos < 4)
2645 len = toint(GET_32BIT(pkt->body + pkt->savedpos));
2650 if (pkt->length - pkt->savedpos < *length)
2652 *p = (char *)(pkt->body + pkt->savedpos);
2653 pkt->savedpos += *length;
2655 static void *ssh_pkt_getdata(struct Packet *pkt, int length)
2657 if (pkt->length - pkt->savedpos < length)
2659 pkt->savedpos += length;
2660 return pkt->body + (pkt->savedpos - length);
2662 static int ssh1_pkt_getrsakey(struct Packet *pkt, struct RSAKey *key,
2663 const unsigned char **keystr)
2667 j = makekey(pkt->body + pkt->savedpos,
2668 pkt->length - pkt->savedpos,
2675 assert(pkt->savedpos < pkt->length);
2679 static Bignum ssh1_pkt_getmp(struct Packet *pkt)
2684 j = ssh1_read_bignum(pkt->body + pkt->savedpos,
2685 pkt->length - pkt->savedpos, &b);
2693 static Bignum ssh2_pkt_getmp(struct Packet *pkt)
2699 ssh_pkt_getstring(pkt, &p, &length);
2704 b = bignum_from_bytes((unsigned char *)p, length);
2709 * Helper function to add an SSH-2 signature blob to a packet.
2710 * Expects to be shown the public key blob as well as the signature
2711 * blob. Normally works just like ssh2_pkt_addstring, but will
2712 * fiddle with the signature packet if necessary for
2713 * BUG_SSH2_RSA_PADDING.
2715 static void ssh2_add_sigblob(Ssh ssh, struct Packet *pkt,
2716 void *pkblob_v, int pkblob_len,
2717 void *sigblob_v, int sigblob_len)
2719 unsigned char *pkblob = (unsigned char *)pkblob_v;
2720 unsigned char *sigblob = (unsigned char *)sigblob_v;
2722 /* dmemdump(pkblob, pkblob_len); */
2723 /* dmemdump(sigblob, sigblob_len); */
2726 * See if this is in fact an ssh-rsa signature and a buggy
2727 * server; otherwise we can just do this the easy way.
2729 if ((ssh->remote_bugs & BUG_SSH2_RSA_PADDING) && pkblob_len > 4+7+4 &&
2730 (GET_32BIT(pkblob) == 7 && !memcmp(pkblob+4, "ssh-rsa", 7))) {
2731 int pos, len, siglen;
2734 * Find the byte length of the modulus.
2737 pos = 4+7; /* skip over "ssh-rsa" */
2738 len = toint(GET_32BIT(pkblob+pos)); /* get length of exponent */
2739 if (len < 0 || len > pkblob_len - pos - 4)
2741 pos += 4 + len; /* skip over exponent */
2742 if (pkblob_len - pos < 4)
2744 len = toint(GET_32BIT(pkblob+pos)); /* find length of modulus */
2745 if (len < 0 || len > pkblob_len - pos - 4)
2747 pos += 4; /* find modulus itself */
2748 while (len > 0 && pkblob[pos] == 0)
2750 /* debug(("modulus length is %d\n", len)); */
2753 * Now find the signature integer.
2755 pos = 4+7; /* skip over "ssh-rsa" */
2756 if (sigblob_len < pos+4)
2758 siglen = toint(GET_32BIT(sigblob+pos));
2759 if (siglen != sigblob_len - pos - 4)
2761 /* debug(("signature length is %d\n", siglen)); */
2763 if (len != siglen) {
2764 unsigned char newlen[4];
2765 ssh2_pkt_addstring_start(pkt);
2766 ssh2_pkt_addstring_data(pkt, (char *)sigblob, pos);
2767 /* dmemdump(sigblob, pos); */
2768 pos += 4; /* point to start of actual sig */
2769 PUT_32BIT(newlen, len);
2770 ssh2_pkt_addstring_data(pkt, (char *)newlen, 4);
2771 /* dmemdump(newlen, 4); */
2773 while (len-- > siglen) {
2774 ssh2_pkt_addstring_data(pkt, (char *)newlen, 1);
2775 /* dmemdump(newlen, 1); */
2777 ssh2_pkt_addstring_data(pkt, (char *)(sigblob+pos), siglen);
2778 /* dmemdump(sigblob+pos, siglen); */
2782 /* Otherwise fall through and do it the easy way. We also come
2783 * here as a fallback if we discover above that the key blob
2784 * is misformatted in some way. */
2788 ssh2_pkt_addstring_start(pkt);
2789 ssh2_pkt_addstring_data(pkt, (char *)sigblob, sigblob_len);
2793 * Examine the remote side's version string and compare it against
2794 * a list of known buggy implementations.
2796 static void ssh_detect_bugs(Ssh ssh, char *vstring)
2798 char *imp; /* pointer to implementation part */
2800 imp += strcspn(imp, "-");
2802 imp += strcspn(imp, "-");
2805 ssh->remote_bugs = 0;
2808 * General notes on server version strings:
2809 * - Not all servers reporting "Cisco-1.25" have all the bugs listed
2810 * here -- in particular, we've heard of one that's perfectly happy
2811 * with SSH1_MSG_IGNOREs -- but this string never seems to change,
2812 * so we can't distinguish them.
2814 if (conf_get_int(ssh->conf, CONF_sshbug_ignore1) == FORCE_ON ||
2815 (conf_get_int(ssh->conf, CONF_sshbug_ignore1) == AUTO &&
2816 (!strcmp(imp, "1.2.18") || !strcmp(imp, "1.2.19") ||
2817 !strcmp(imp, "1.2.20") || !strcmp(imp, "1.2.21") ||
2818 !strcmp(imp, "1.2.22") || !strcmp(imp, "Cisco-1.25") ||
2819 !strcmp(imp, "OSU_1.4alpha3") || !strcmp(imp, "OSU_1.5alpha4")))) {
2821 * These versions don't support SSH1_MSG_IGNORE, so we have
2822 * to use a different defence against password length
2825 ssh->remote_bugs |= BUG_CHOKES_ON_SSH1_IGNORE;
2826 logevent("We believe remote version has SSH-1 ignore bug");
2829 if (conf_get_int(ssh->conf, CONF_sshbug_plainpw1) == FORCE_ON ||
2830 (conf_get_int(ssh->conf, CONF_sshbug_plainpw1) == AUTO &&
2831 (!strcmp(imp, "Cisco-1.25") || !strcmp(imp, "OSU_1.4alpha3")))) {
2833 * These versions need a plain password sent; they can't
2834 * handle having a null and a random length of data after
2837 ssh->remote_bugs |= BUG_NEEDS_SSH1_PLAIN_PASSWORD;
2838 logevent("We believe remote version needs a plain SSH-1 password");
2841 if (conf_get_int(ssh->conf, CONF_sshbug_rsa1) == FORCE_ON ||
2842 (conf_get_int(ssh->conf, CONF_sshbug_rsa1) == AUTO &&
2843 (!strcmp(imp, "Cisco-1.25")))) {
2845 * These versions apparently have no clue whatever about
2846 * RSA authentication and will panic and die if they see
2847 * an AUTH_RSA message.
2849 ssh->remote_bugs |= BUG_CHOKES_ON_RSA;
2850 logevent("We believe remote version can't handle SSH-1 RSA authentication");
2853 if (conf_get_int(ssh->conf, CONF_sshbug_hmac2) == FORCE_ON ||
2854 (conf_get_int(ssh->conf, CONF_sshbug_hmac2) == AUTO &&
2855 !wc_match("* VShell", imp) &&
2856 (wc_match("2.1.0*", imp) || wc_match("2.0.*", imp) ||
2857 wc_match("2.2.0*", imp) || wc_match("2.3.0*", imp) ||
2858 wc_match("2.1 *", imp)))) {
2860 * These versions have the HMAC bug.
2862 ssh->remote_bugs |= BUG_SSH2_HMAC;
2863 logevent("We believe remote version has SSH-2 HMAC bug");
2866 if (conf_get_int(ssh->conf, CONF_sshbug_derivekey2) == FORCE_ON ||
2867 (conf_get_int(ssh->conf, CONF_sshbug_derivekey2) == AUTO &&
2868 !wc_match("* VShell", imp) &&
2869 (wc_match("2.0.0*", imp) || wc_match("2.0.10*", imp) ))) {
2871 * These versions have the key-derivation bug (failing to
2872 * include the literal shared secret in the hashes that
2873 * generate the keys).
2875 ssh->remote_bugs |= BUG_SSH2_DERIVEKEY;
2876 logevent("We believe remote version has SSH-2 key-derivation bug");
2879 if (conf_get_int(ssh->conf, CONF_sshbug_rsapad2) == FORCE_ON ||
2880 (conf_get_int(ssh->conf, CONF_sshbug_rsapad2) == AUTO &&
2881 (wc_match("OpenSSH_2.[5-9]*", imp) ||
2882 wc_match("OpenSSH_3.[0-2]*", imp) ||
2883 wc_match("mod_sftp/0.[0-8]*", imp) ||
2884 wc_match("mod_sftp/0.9.[0-8]", imp)))) {
2886 * These versions have the SSH-2 RSA padding bug.
2888 ssh->remote_bugs |= BUG_SSH2_RSA_PADDING;
2889 logevent("We believe remote version has SSH-2 RSA padding bug");
2892 if (conf_get_int(ssh->conf, CONF_sshbug_pksessid2) == FORCE_ON ||
2893 (conf_get_int(ssh->conf, CONF_sshbug_pksessid2) == AUTO &&
2894 wc_match("OpenSSH_2.[0-2]*", imp))) {
2896 * These versions have the SSH-2 session-ID bug in
2897 * public-key authentication.
2899 ssh->remote_bugs |= BUG_SSH2_PK_SESSIONID;
2900 logevent("We believe remote version has SSH-2 public-key-session-ID bug");
2903 if (conf_get_int(ssh->conf, CONF_sshbug_rekey2) == FORCE_ON ||
2904 (conf_get_int(ssh->conf, CONF_sshbug_rekey2) == AUTO &&
2905 (wc_match("DigiSSH_2.0", imp) ||
2906 wc_match("OpenSSH_2.[0-4]*", imp) ||
2907 wc_match("OpenSSH_2.5.[0-3]*", imp) ||
2908 wc_match("Sun_SSH_1.0", imp) ||
2909 wc_match("Sun_SSH_1.0.1", imp) ||
2910 /* All versions <= 1.2.6 (they changed their format in 1.2.7) */
2911 wc_match("WeOnlyDo-*", imp)))) {
2913 * These versions have the SSH-2 rekey bug.
2915 ssh->remote_bugs |= BUG_SSH2_REKEY;
2916 logevent("We believe remote version has SSH-2 rekey bug");
2919 if (conf_get_int(ssh->conf, CONF_sshbug_maxpkt2) == FORCE_ON ||
2920 (conf_get_int(ssh->conf, CONF_sshbug_maxpkt2) == AUTO &&
2921 (wc_match("1.36_sshlib GlobalSCAPE", imp) ||
2922 wc_match("1.36 sshlib: GlobalScape", imp)))) {
2924 * This version ignores our makpkt and needs to be throttled.
2926 ssh->remote_bugs |= BUG_SSH2_MAXPKT;
2927 logevent("We believe remote version ignores SSH-2 maximum packet size");
2930 if (conf_get_int(ssh->conf, CONF_sshbug_ignore2) == FORCE_ON) {
2932 * Servers that don't support SSH2_MSG_IGNORE. Currently,
2933 * none detected automatically.
2935 ssh->remote_bugs |= BUG_CHOKES_ON_SSH2_IGNORE;
2936 logevent("We believe remote version has SSH-2 ignore bug");
2939 if (conf_get_int(ssh->conf, CONF_sshbug_oldgex2) == FORCE_ON ||
2940 (conf_get_int(ssh->conf, CONF_sshbug_oldgex2) == AUTO &&
2941 (wc_match("OpenSSH_2.[235]*", imp)))) {
2943 * These versions only support the original (pre-RFC4419)
2944 * SSH-2 GEX request, and disconnect with a protocol error if
2945 * we use the newer version.
2947 ssh->remote_bugs |= BUG_SSH2_OLDGEX;
2948 logevent("We believe remote version has outdated SSH-2 GEX");
2951 if (conf_get_int(ssh->conf, CONF_sshbug_winadj) == FORCE_ON) {
2953 * Servers that don't support our winadj request for one
2954 * reason or another. Currently, none detected automatically.
2956 ssh->remote_bugs |= BUG_CHOKES_ON_WINADJ;
2957 logevent("We believe remote version has winadj bug");
2960 if (conf_get_int(ssh->conf, CONF_sshbug_chanreq) == FORCE_ON ||
2961 (conf_get_int(ssh->conf, CONF_sshbug_chanreq) == AUTO &&
2962 (wc_match("OpenSSH_[2-5].*", imp) ||
2963 wc_match("OpenSSH_6.[0-6]*", imp) ||
2964 wc_match("dropbear_0.[2-4][0-9]*", imp) ||
2965 wc_match("dropbear_0.5[01]*", imp)))) {
2967 * These versions have the SSH-2 channel request bug.
2968 * OpenSSH 6.7 and above do not:
2969 * https://bugzilla.mindrot.org/show_bug.cgi?id=1818
2970 * dropbear_0.52 and above do not:
2971 * https://secure.ucc.asn.au/hg/dropbear/rev/cd02449b709c
2973 ssh->remote_bugs |= BUG_SENDS_LATE_REQUEST_REPLY;
2974 logevent("We believe remote version has SSH-2 channel request bug");
2979 * The `software version' part of an SSH version string is required
2980 * to contain no spaces or minus signs.
2982 static void ssh_fix_verstring(char *str)
2984 /* Eat "<protoversion>-". */
2985 while (*str && *str != '-') str++;
2986 assert(*str == '-'); str++;
2988 /* Convert minus signs and spaces in the remaining string into
2991 if (*str == '-' || *str == ' ')
2998 * Send an appropriate SSH version string.
3000 static void ssh_send_verstring(Ssh ssh, const char *protoname, char *svers)
3004 if (ssh->version == 2) {
3006 * Construct a v2 version string.
3008 verstring = dupprintf("%s2.0-%s\015\012", protoname, sshver);
3011 * Construct a v1 version string.
3013 assert(!strcmp(protoname, "SSH-")); /* no v1 bare connection protocol */
3014 verstring = dupprintf("SSH-%s-%s\012",
3015 (ssh_versioncmp(svers, "1.5") <= 0 ?
3020 ssh_fix_verstring(verstring + strlen(protoname));
3022 /* FUZZING make PuTTY insecure, so make live use difficult. */
3026 if (ssh->version == 2) {
3029 * Record our version string.
3031 len = strcspn(verstring, "\015\012");
3032 ssh->v_c = snewn(len + 1, char);
3033 memcpy(ssh->v_c, verstring, len);
3037 logeventf(ssh, "We claim version: %.*s",
3038 strcspn(verstring, "\015\012"), verstring);
3039 s_write(ssh, verstring, strlen(verstring));
3043 static int do_ssh_init(Ssh ssh, unsigned char c)
3045 static const char protoname[] = "SSH-";
3047 struct do_ssh_init_state {
3056 crState(do_ssh_init_state);
3060 /* Search for a line beginning with the protocol name prefix in
3063 for (s->i = 0; protoname[s->i]; s->i++) {
3064 if ((char)c != protoname[s->i]) goto no;
3074 ssh->session_started = TRUE;
3076 s->vstrsize = sizeof(protoname) + 16;
3077 s->vstring = snewn(s->vstrsize, char);
3078 strcpy(s->vstring, protoname);
3079 s->vslen = strlen(protoname);
3082 if (s->vslen >= s->vstrsize - 1) {
3084 s->vstring = sresize(s->vstring, s->vstrsize, char);
3086 s->vstring[s->vslen++] = c;
3089 s->version[s->i] = '\0';
3091 } else if (s->i < sizeof(s->version) - 1)
3092 s->version[s->i++] = c;
3093 } else if (c == '\012')
3095 crReturn(1); /* get another char */
3098 ssh->agentfwd_enabled = FALSE;
3099 ssh->rdpkt2_state.incoming_sequence = 0;
3101 s->vstring[s->vslen] = 0;
3102 s->vstring[strcspn(s->vstring, "\015\012")] = '\0';/* remove EOL chars */
3103 logeventf(ssh, "Server version: %s", s->vstring);
3104 ssh_detect_bugs(ssh, s->vstring);
3107 * Decide which SSH protocol version to support.
3110 /* Anything strictly below "2.0" means protocol 1 is supported. */
3111 s->proto1 = ssh_versioncmp(s->version, "2.0") < 0;
3112 /* Anything greater or equal to "1.99" means protocol 2 is supported. */
3113 s->proto2 = ssh_versioncmp(s->version, "1.99") >= 0;
3115 if (conf_get_int(ssh->conf, CONF_sshprot) == 0 && !s->proto1) {
3116 bombout(("SSH protocol version 1 required by configuration but "
3117 "not provided by server"));
3120 if (conf_get_int(ssh->conf, CONF_sshprot) == 3 && !s->proto2) {
3121 bombout(("SSH protocol version 2 required by configuration but "
3122 "not provided by server"));
3126 if (s->proto2 && (conf_get_int(ssh->conf, CONF_sshprot) >= 2 || !s->proto1))
3131 logeventf(ssh, "Using SSH protocol version %d", ssh->version);
3133 /* Send the version string, if we haven't already */
3134 if (conf_get_int(ssh->conf, CONF_sshprot) != 3)
3135 ssh_send_verstring(ssh, protoname, s->version);
3137 if (ssh->version == 2) {
3140 * Record their version string.
3142 len = strcspn(s->vstring, "\015\012");
3143 ssh->v_s = snewn(len + 1, char);
3144 memcpy(ssh->v_s, s->vstring, len);
3148 * Initialise SSH-2 protocol.
3150 ssh->protocol = ssh2_protocol;
3151 ssh2_protocol_setup(ssh);
3152 ssh->s_rdpkt = ssh2_rdpkt;
3155 * Initialise SSH-1 protocol.
3157 ssh->protocol = ssh1_protocol;
3158 ssh1_protocol_setup(ssh);
3159 ssh->s_rdpkt = ssh1_rdpkt;
3161 if (ssh->version == 2)
3162 do_ssh2_transport(ssh, NULL, -1, NULL);
3164 update_specials_menu(ssh->frontend);
3165 ssh->state = SSH_STATE_BEFORE_SIZE;
3166 ssh->pinger = pinger_new(ssh->conf, &ssh_backend, ssh);
3173 static int do_ssh_connection_init(Ssh ssh, unsigned char c)
3176 * Ordinary SSH begins with the banner "SSH-x.y-...". This is just
3177 * the ssh-connection part, extracted and given a trivial binary
3178 * packet protocol, so we replace 'SSH-' at the start with a new
3179 * name. In proper SSH style (though of course this part of the
3180 * proper SSH protocol _isn't_ subject to this kind of
3181 * DNS-domain-based extension), we define the new name in our
3184 static const char protoname[] =
3185 "SSHCONNECTION@putty.projects.tartarus.org-";
3187 struct do_ssh_connection_init_state {
3195 crState(do_ssh_connection_init_state);
3199 /* Search for a line beginning with the protocol name prefix in
3202 for (s->i = 0; protoname[s->i]; s->i++) {
3203 if ((char)c != protoname[s->i]) goto no;
3213 s->vstrsize = sizeof(protoname) + 16;
3214 s->vstring = snewn(s->vstrsize, char);
3215 strcpy(s->vstring, protoname);
3216 s->vslen = strlen(protoname);
3219 if (s->vslen >= s->vstrsize - 1) {
3221 s->vstring = sresize(s->vstring, s->vstrsize, char);
3223 s->vstring[s->vslen++] = c;
3226 s->version[s->i] = '\0';
3228 } else if (s->i < sizeof(s->version) - 1)
3229 s->version[s->i++] = c;
3230 } else if (c == '\012')
3232 crReturn(1); /* get another char */
3235 ssh->agentfwd_enabled = FALSE;
3236 ssh->rdpkt2_bare_state.incoming_sequence = 0;
3238 s->vstring[s->vslen] = 0;
3239 s->vstring[strcspn(s->vstring, "\015\012")] = '\0';/* remove EOL chars */
3240 logeventf(ssh, "Server version: %s", s->vstring);
3241 ssh_detect_bugs(ssh, s->vstring);
3244 * Decide which SSH protocol version to support. This is easy in
3245 * bare ssh-connection mode: only 2.0 is legal.
3247 if (ssh_versioncmp(s->version, "2.0") < 0) {
3248 bombout(("Server announces compatibility with SSH-1 in bare ssh-connection protocol"));
3251 if (conf_get_int(ssh->conf, CONF_sshprot) == 0) {
3252 bombout(("Bare ssh-connection protocol cannot be run in SSH-1-only mode"));
3258 logeventf(ssh, "Using bare ssh-connection protocol");
3260 /* Send the version string, if we haven't already */
3261 ssh_send_verstring(ssh, protoname, s->version);
3264 * Initialise bare connection protocol.
3266 ssh->protocol = ssh2_bare_connection_protocol;
3267 ssh2_bare_connection_protocol_setup(ssh);
3268 ssh->s_rdpkt = ssh2_bare_connection_rdpkt;
3270 update_specials_menu(ssh->frontend);
3271 ssh->state = SSH_STATE_BEFORE_SIZE;
3272 ssh->pinger = pinger_new(ssh->conf, &ssh_backend, ssh);
3275 * Get authconn (really just conn) under way.
3277 do_ssh2_authconn(ssh, NULL, 0, NULL);
3284 static void ssh_process_incoming_data(Ssh ssh,
3285 const unsigned char **data, int *datalen)
3287 struct Packet *pktin;
3289 pktin = ssh->s_rdpkt(ssh, data, datalen);
3291 ssh->protocol(ssh, NULL, 0, pktin);
3292 ssh_free_packet(pktin);
3296 static void ssh_queue_incoming_data(Ssh ssh,
3297 const unsigned char **data, int *datalen)
3299 bufchain_add(&ssh->queued_incoming_data, *data, *datalen);
3304 static void ssh_process_queued_incoming_data(Ssh ssh)
3307 const unsigned char *data;
3310 while (!ssh->frozen && bufchain_size(&ssh->queued_incoming_data)) {
3311 bufchain_prefix(&ssh->queued_incoming_data, &vdata, &len);
3315 while (!ssh->frozen && len > 0)
3316 ssh_process_incoming_data(ssh, &data, &len);
3319 bufchain_consume(&ssh->queued_incoming_data, origlen - len);
3323 static void ssh_set_frozen(Ssh ssh, int frozen)
3326 sk_set_frozen(ssh->s, frozen);
3327 ssh->frozen = frozen;
3330 static void ssh_gotdata(Ssh ssh, const unsigned char *data, int datalen)
3332 /* Log raw data, if we're in that mode. */
3334 log_packet(ssh->logctx, PKT_INCOMING, -1, NULL, data, datalen,
3335 0, NULL, NULL, 0, NULL);
3337 crBegin(ssh->ssh_gotdata_crstate);
3340 * To begin with, feed the characters one by one to the
3341 * protocol initialisation / selection function do_ssh_init().
3342 * When that returns 0, we're done with the initial greeting
3343 * exchange and can move on to packet discipline.
3346 int ret; /* need not be kept across crReturn */
3348 crReturnV; /* more data please */
3349 ret = ssh->do_ssh_init(ssh, *data);
3357 * We emerge from that loop when the initial negotiation is
3358 * over and we have selected an s_rdpkt function. Now pass
3359 * everything to s_rdpkt, and then pass the resulting packets
3360 * to the proper protocol handler.
3364 while (bufchain_size(&ssh->queued_incoming_data) > 0 || datalen > 0) {
3366 ssh_queue_incoming_data(ssh, &data, &datalen);
3367 /* This uses up all data and cannot cause anything interesting
3368 * to happen; indeed, for anything to happen at all, we must
3369 * return, so break out. */
3371 } else if (bufchain_size(&ssh->queued_incoming_data) > 0) {
3372 /* This uses up some or all data, and may freeze the
3374 ssh_process_queued_incoming_data(ssh);
3376 /* This uses up some or all data, and may freeze the
3378 ssh_process_incoming_data(ssh, &data, &datalen);
3380 /* FIXME this is probably EBW. */
3381 if (ssh->state == SSH_STATE_CLOSED)
3384 /* We're out of data. Go and get some more. */
3390 static int ssh_do_close(Ssh ssh, int notify_exit)
3393 struct ssh_channel *c;
3395 ssh->state = SSH_STATE_CLOSED;
3396 expire_timer_context(ssh);
3401 notify_remote_exit(ssh->frontend);
3406 * Now we must shut down any port- and X-forwarded channels going
3407 * through this connection.
3409 if (ssh->channels) {
3410 while (NULL != (c = index234(ssh->channels, 0))) {
3413 x11_close(c->u.x11.xconn);
3416 case CHAN_SOCKDATA_DORMANT:
3417 pfd_close(c->u.pfd.pf);
3420 del234(ssh->channels, c); /* moving next one to index 0 */
3421 if (ssh->version == 2)
3422 bufchain_clear(&c->v.v2.outbuffer);
3427 * Go through port-forwardings, and close any associated
3428 * listening sockets.
3430 if (ssh->portfwds) {
3431 struct ssh_portfwd *pf;
3432 while (NULL != (pf = index234(ssh->portfwds, 0))) {
3433 /* Dispose of any listening socket. */
3435 pfl_terminate(pf->local);
3436 del234(ssh->portfwds, pf); /* moving next one to index 0 */
3439 freetree234(ssh->portfwds);
3440 ssh->portfwds = NULL;
3444 * Also stop attempting to connection-share.
3446 if (ssh->connshare) {
3447 sharestate_free(ssh->connshare);
3448 ssh->connshare = NULL;
3454 static void ssh_socket_log(Plug plug, int type, SockAddr addr, int port,
3455 const char *error_msg, int error_code)
3457 Ssh ssh = (Ssh) plug;
3460 * While we're attempting connection sharing, don't loudly log
3461 * everything that happens. Real TCP connections need to be logged
3462 * when we _start_ trying to connect, because it might be ages
3463 * before they respond if something goes wrong; but connection
3464 * sharing is local and quick to respond, and it's sufficient to
3465 * simply wait and see whether it worked afterwards.
3468 if (!ssh->attempting_connshare)
3469 backend_socket_log(ssh->frontend, type, addr, port,
3470 error_msg, error_code, ssh->conf,
3471 ssh->session_started);
3474 void ssh_connshare_log(Ssh ssh, int event, const char *logtext,
3475 const char *ds_err, const char *us_err)
3477 if (event == SHARE_NONE) {
3478 /* In this case, 'logtext' is an error message indicating a
3479 * reason why connection sharing couldn't be set up _at all_.
3480 * Failing that, ds_err and us_err indicate why we couldn't be
3481 * a downstream and an upstream respectively. */
3483 logeventf(ssh, "Could not set up connection sharing: %s", logtext);
3486 logeventf(ssh, "Could not set up connection sharing"
3487 " as downstream: %s", ds_err);
3489 logeventf(ssh, "Could not set up connection sharing"
3490 " as upstream: %s", us_err);
3492 } else if (event == SHARE_DOWNSTREAM) {
3493 /* In this case, 'logtext' is a local endpoint address */
3494 logeventf(ssh, "Using existing shared connection at %s", logtext);
3495 /* Also we should mention this in the console window to avoid
3496 * confusing users as to why this window doesn't behave the
3498 if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
3499 c_write_str(ssh,"Reusing a shared connection to this server.\r\n");
3501 } else if (event == SHARE_UPSTREAM) {
3502 /* In this case, 'logtext' is a local endpoint address too */
3503 logeventf(ssh, "Sharing this connection at %s", logtext);
3507 static int ssh_closing(Plug plug, const char *error_msg, int error_code,
3510 Ssh ssh = (Ssh) plug;
3511 int need_notify = ssh_do_close(ssh, FALSE);
3514 if (!ssh->close_expected)
3515 error_msg = "Server unexpectedly closed network connection";
3517 error_msg = "Server closed network connection";
3520 if (ssh->close_expected && ssh->clean_exit && ssh->exitcode < 0)
3524 notify_remote_exit(ssh->frontend);
3527 logevent(error_msg);
3528 if (!ssh->close_expected || !ssh->clean_exit)
3529 connection_fatal(ssh->frontend, "%s", error_msg);
3533 static int ssh_receive(Plug plug, int urgent, char *data, int len)
3535 Ssh ssh = (Ssh) plug;
3536 ssh_gotdata(ssh, (unsigned char *)data, len);
3537 if (ssh->state == SSH_STATE_CLOSED) {
3538 ssh_do_close(ssh, TRUE);
3544 static void ssh_sent(Plug plug, int bufsize)
3546 Ssh ssh = (Ssh) plug;
3548 * If the send backlog on the SSH socket itself clears, we
3549 * should unthrottle the whole world if it was throttled.
3551 if (bufsize < SSH_MAX_BACKLOG)
3552 ssh_throttle_all(ssh, 0, bufsize);
3555 static void ssh_hostport_setup(const char *host, int port, Conf *conf,
3556 char **savedhost, int *savedport,
3559 char *loghost = conf_get_str(conf, CONF_loghost);
3561 *loghost_ret = loghost;
3567 tmphost = dupstr(loghost);
3568 *savedport = 22; /* default ssh port */
3571 * A colon suffix on the hostname string also lets us affect
3572 * savedport. (Unless there are multiple colons, in which case
3573 * we assume this is an unbracketed IPv6 literal.)
3575 colon = host_strrchr(tmphost, ':');
3576 if (colon && colon == host_strchr(tmphost, ':')) {
3579 *savedport = atoi(colon);
3582 *savedhost = host_strduptrim(tmphost);
3585 *savedhost = host_strduptrim(host);
3587 port = 22; /* default ssh port */
3592 static int ssh_test_for_upstream(const char *host, int port, Conf *conf)
3598 random_ref(); /* platform may need this to determine share socket name */
3599 ssh_hostport_setup(host, port, conf, &savedhost, &savedport, NULL);
3600 ret = ssh_share_test_for_upstream(savedhost, savedport, conf);
3608 * Connect to specified host and port.
3609 * Returns an error message, or NULL on success.
3610 * Also places the canonical host name into `realhost'. It must be
3611 * freed by the caller.
3613 static const char *connect_to_host(Ssh ssh, const char *host, int port,
3614 char **realhost, int nodelay, int keepalive)
3616 static const struct plug_function_table fn_table = {
3627 int addressfamily, sshprot;
3629 ssh_hostport_setup(host, port, ssh->conf,
3630 &ssh->savedhost, &ssh->savedport, &loghost);
3632 ssh->fn = &fn_table; /* make 'ssh' usable as a Plug */
3635 * Try connection-sharing, in case that means we don't open a
3636 * socket after all. ssh_connection_sharing_init will connect to a
3637 * previously established upstream if it can, and failing that,
3638 * establish a listening socket for _us_ to be the upstream. In
3639 * the latter case it will return NULL just as if it had done
3640 * nothing, because here we only need to care if we're a
3641 * downstream and need to do our connection setup differently.
3643 ssh->connshare = NULL;
3644 ssh->attempting_connshare = TRUE; /* affects socket logging behaviour */
3645 ssh->s = ssh_connection_sharing_init(ssh->savedhost, ssh->savedport,
3646 ssh->conf, ssh, &ssh->connshare);
3647 ssh->attempting_connshare = FALSE;
3648 if (ssh->s != NULL) {
3650 * We are a downstream.
3652 ssh->bare_connection = TRUE;
3653 ssh->do_ssh_init = do_ssh_connection_init;
3654 ssh->fullhostname = NULL;
3655 *realhost = dupstr(host); /* best we can do */
3658 * We're not a downstream, so open a normal socket.
3660 ssh->do_ssh_init = do_ssh_init;
3665 addressfamily = conf_get_int(ssh->conf, CONF_addressfamily);
3666 addr = name_lookup(host, port, realhost, ssh->conf, addressfamily,
3667 ssh->frontend, "SSH connection");
3668 if ((err = sk_addr_error(addr)) != NULL) {
3672 ssh->fullhostname = dupstr(*realhost); /* save in case of GSSAPI */
3674 ssh->s = new_connection(addr, *realhost, port,
3675 0, 1, nodelay, keepalive,
3676 (Plug) ssh, ssh->conf);
3677 if ((err = sk_socket_error(ssh->s)) != NULL) {
3679 notify_remote_exit(ssh->frontend);
3685 * If the SSH version number's fixed, set it now, and if it's SSH-2,
3686 * send the version string too.
3688 sshprot = conf_get_int(ssh->conf, CONF_sshprot);
3691 if (sshprot == 3 && !ssh->bare_connection) {
3693 ssh_send_verstring(ssh, "SSH-", NULL);
3697 * loghost, if configured, overrides realhost.
3701 *realhost = dupstr(loghost);
3708 * Throttle or unthrottle the SSH connection.
3710 static void ssh_throttle_conn(Ssh ssh, int adjust)
3712 int old_count = ssh->conn_throttle_count;
3713 ssh->conn_throttle_count += adjust;
3714 assert(ssh->conn_throttle_count >= 0);
3715 if (ssh->conn_throttle_count && !old_count) {
3716 ssh_set_frozen(ssh, 1);
3717 } else if (!ssh->conn_throttle_count && old_count) {
3718 ssh_set_frozen(ssh, 0);
3723 * Throttle or unthrottle _all_ local data streams (for when sends
3724 * on the SSH connection itself back up).
3726 static void ssh_throttle_all(Ssh ssh, int enable, int bufsize)
3729 struct ssh_channel *c;
3731 if (enable == ssh->throttled_all)
3733 ssh->throttled_all = enable;
3734 ssh->overall_bufsize = bufsize;
3737 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
3739 case CHAN_MAINSESSION:
3741 * This is treated separately, outside the switch.
3745 x11_override_throttle(c->u.x11.xconn, enable);
3748 /* Agent channels require no buffer management. */
3751 pfd_override_throttle(c->u.pfd.pf, enable);
3757 static void ssh_agent_callback(void *sshv, void *reply, int replylen)
3759 Ssh ssh = (Ssh) sshv;
3761 ssh->agent_response = reply;
3762 ssh->agent_response_len = replylen;
3764 if (ssh->version == 1)
3765 do_ssh1_login(ssh, NULL, -1, NULL);
3767 do_ssh2_authconn(ssh, NULL, -1, NULL);
3770 static void ssh_dialog_callback(void *sshv, int ret)
3772 Ssh ssh = (Ssh) sshv;
3774 ssh->user_response = ret;
3776 if (ssh->version == 1)
3777 do_ssh1_login(ssh, NULL, -1, NULL);
3779 do_ssh2_transport(ssh, NULL, -1, NULL);
3782 * This may have unfrozen the SSH connection, so do a
3785 ssh_process_queued_incoming_data(ssh);
3788 static void ssh_agentf_callback(void *cv, void *reply, int replylen)
3790 struct ssh_channel *c = (struct ssh_channel *)cv;
3792 const void *sentreply = reply;
3794 c->u.a.outstanding_requests--;
3796 /* Fake SSH_AGENT_FAILURE. */
3797 sentreply = "\0\0\0\1\5";
3800 if (ssh->version == 2) {
3801 ssh2_add_channel_data(c, sentreply, replylen);
3804 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
3805 PKT_INT, c->remoteid,
3807 PKT_DATA, sentreply, replylen,
3813 * If we've already seen an incoming EOF but haven't sent an
3814 * outgoing one, this may be the moment to send it.
3816 if (c->u.a.outstanding_requests == 0 && (c->closes & CLOSES_RCVD_EOF))
3817 sshfwd_write_eof(c);
3821 * Client-initiated disconnection. Send a DISCONNECT if `wire_reason'
3822 * non-NULL, otherwise just close the connection. `client_reason' == NULL
3823 * => log `wire_reason'.
3825 static void ssh_disconnect(Ssh ssh, const char *client_reason,
3826 const char *wire_reason,
3827 int code, int clean_exit)
3831 client_reason = wire_reason;
3833 error = dupprintf("Disconnected: %s", client_reason);
3835 error = dupstr("Disconnected");
3837 if (ssh->version == 1) {
3838 send_packet(ssh, SSH1_MSG_DISCONNECT, PKT_STR, wire_reason,
3840 } else if (ssh->version == 2) {
3841 struct Packet *pktout = ssh2_pkt_init(SSH2_MSG_DISCONNECT);
3842 ssh2_pkt_adduint32(pktout, code);
3843 ssh2_pkt_addstring(pktout, wire_reason);
3844 ssh2_pkt_addstring(pktout, "en"); /* language tag */
3845 ssh2_pkt_send_noqueue(ssh, pktout);
3848 ssh->close_expected = TRUE;
3849 ssh->clean_exit = clean_exit;
3850 ssh_closing((Plug)ssh, error, 0, 0);
3854 int verify_ssh_manual_host_key(Ssh ssh, const char *fingerprint,
3855 const struct ssh_signkey *ssh2keytype,
3858 if (!conf_get_str_nthstrkey(ssh->conf, CONF_ssh_manual_hostkeys, 0)) {
3859 return -1; /* no manual keys configured */
3864 * The fingerprint string we've been given will have things
3865 * like 'ssh-rsa 2048' at the front of it. Strip those off and
3866 * narrow down to just the colon-separated hex block at the
3867 * end of the string.
3869 const char *p = strrchr(fingerprint, ' ');
3870 fingerprint = p ? p+1 : fingerprint;
3871 /* Quick sanity checks, including making sure it's in lowercase */
3872 assert(strlen(fingerprint) == 16*3 - 1);
3873 assert(fingerprint[2] == ':');
3874 assert(fingerprint[strspn(fingerprint, "0123456789abcdef:")] == 0);
3876 if (conf_get_str_str_opt(ssh->conf, CONF_ssh_manual_hostkeys,
3878 return 1; /* success */
3883 * Construct the base64-encoded public key blob and see if
3886 unsigned char *binblob;
3888 int binlen, atoms, i;
3889 binblob = ssh2keytype->public_blob(ssh2keydata, &binlen);
3890 atoms = (binlen + 2) / 3;
3891 base64blob = snewn(atoms * 4 + 1, char);
3892 for (i = 0; i < atoms; i++)
3893 base64_encode_atom(binblob + 3*i, binlen - 3*i, base64blob + 4*i);
3894 base64blob[atoms * 4] = '\0';
3896 if (conf_get_str_str_opt(ssh->conf, CONF_ssh_manual_hostkeys,
3899 return 1; /* success */
3908 * Handle the key exchange and user authentication phases.
3910 static int do_ssh1_login(Ssh ssh, const unsigned char *in, int inlen,
3911 struct Packet *pktin)
3914 unsigned char cookie[8], *ptr;
3915 struct MD5Context md5c;
3916 struct do_ssh1_login_state {
3919 unsigned char *rsabuf;
3920 const unsigned char *keystr1, *keystr2;
3921 unsigned long supported_ciphers_mask, supported_auths_mask;
3922 int tried_publickey, tried_agent;
3923 int tis_auth_refused, ccard_auth_refused;
3924 unsigned char session_id[16];
3926 void *publickey_blob;
3927 int publickey_bloblen;
3928 char *publickey_comment;
3929 int privatekey_available, privatekey_encrypted;
3930 prompts_t *cur_prompt;
3933 unsigned char request[5], *response, *p;
3943 struct RSAKey servkey, hostkey;
3945 crState(do_ssh1_login_state);
3952 if (pktin->type != SSH1_SMSG_PUBLIC_KEY) {
3953 bombout(("Public key packet not received"));
3957 logevent("Received public keys");
3959 ptr = ssh_pkt_getdata(pktin, 8);
3961 bombout(("SSH-1 public key packet stopped before random cookie"));
3964 memcpy(cookie, ptr, 8);
3966 if (!ssh1_pkt_getrsakey(pktin, &s->servkey, &s->keystr1) ||
3967 !ssh1_pkt_getrsakey(pktin, &s->hostkey, &s->keystr2)) {
3968 bombout(("Failed to read SSH-1 public keys from public key packet"));
3973 * Log the host key fingerprint.
3977 logevent("Host key fingerprint is:");
3978 strcpy(logmsg, " ");
3979 s->hostkey.comment = NULL;
3980 rsa_fingerprint(logmsg + strlen(logmsg),
3981 sizeof(logmsg) - strlen(logmsg), &s->hostkey);
3985 ssh->v1_remote_protoflags = ssh_pkt_getuint32(pktin);
3986 s->supported_ciphers_mask = ssh_pkt_getuint32(pktin);
3987 s->supported_auths_mask = ssh_pkt_getuint32(pktin);
3988 if ((ssh->remote_bugs & BUG_CHOKES_ON_RSA))
3989 s->supported_auths_mask &= ~(1 << SSH1_AUTH_RSA);
3991 ssh->v1_local_protoflags =
3992 ssh->v1_remote_protoflags & SSH1_PROTOFLAGS_SUPPORTED;
3993 ssh->v1_local_protoflags |= SSH1_PROTOFLAG_SCREEN_NUMBER;
3996 MD5Update(&md5c, s->keystr2, s->hostkey.bytes);
3997 MD5Update(&md5c, s->keystr1, s->servkey.bytes);
3998 MD5Update(&md5c, cookie, 8);
3999 MD5Final(s->session_id, &md5c);
4001 for (i = 0; i < 32; i++)
4002 ssh->session_key[i] = random_byte();
4005 * Verify that the `bits' and `bytes' parameters match.
4007 if (s->hostkey.bits > s->hostkey.bytes * 8 ||
4008 s->servkey.bits > s->servkey.bytes * 8) {
4009 bombout(("SSH-1 public keys were badly formatted"));
4013 s->len = (s->hostkey.bytes > s->servkey.bytes ?
4014 s->hostkey.bytes : s->servkey.bytes);
4016 s->rsabuf = snewn(s->len, unsigned char);
4019 * Verify the host key.
4023 * First format the key into a string.
4025 int len = rsastr_len(&s->hostkey);
4026 char fingerprint[100];
4027 char *keystr = snewn(len, char);
4028 rsastr_fmt(keystr, &s->hostkey);
4029 rsa_fingerprint(fingerprint, sizeof(fingerprint), &s->hostkey);
4031 /* First check against manually configured host keys. */
4032 s->dlgret = verify_ssh_manual_host_key(ssh, fingerprint, NULL, NULL);
4033 if (s->dlgret == 0) { /* did not match */
4034 bombout(("Host key did not appear in manually configured list"));
4037 } else if (s->dlgret < 0) { /* none configured; use standard handling */
4038 ssh_set_frozen(ssh, 1);
4039 s->dlgret = verify_ssh_host_key(ssh->frontend,
4040 ssh->savedhost, ssh->savedport,
4041 "rsa", keystr, fingerprint,
4042 ssh_dialog_callback, ssh);
4047 if (s->dlgret < 0) {
4051 bombout(("Unexpected data from server while waiting"
4052 " for user host key response"));
4055 } while (pktin || inlen > 0);
4056 s->dlgret = ssh->user_response;
4058 ssh_set_frozen(ssh, 0);
4060 if (s->dlgret == 0) {
4061 ssh_disconnect(ssh, "User aborted at host key verification",
4070 for (i = 0; i < 32; i++) {
4071 s->rsabuf[i] = ssh->session_key[i];
4073 s->rsabuf[i] ^= s->session_id[i];
4076 if (s->hostkey.bytes > s->servkey.bytes) {
4077 ret = rsaencrypt(s->rsabuf, 32, &s->servkey);
4079 ret = rsaencrypt(s->rsabuf, s->servkey.bytes, &s->hostkey);
4081 ret = rsaencrypt(s->rsabuf, 32, &s->hostkey);
4083 ret = rsaencrypt(s->rsabuf, s->hostkey.bytes, &s->servkey);
4086 bombout(("SSH-1 public key encryptions failed due to bad formatting"));
4090 logevent("Encrypted session key");
4093 int cipher_chosen = 0, warn = 0;
4094 const char *cipher_string = NULL;
4096 for (i = 0; !cipher_chosen && i < CIPHER_MAX; i++) {
4097 int next_cipher = conf_get_int_int(ssh->conf,
4098 CONF_ssh_cipherlist, i);
4099 if (next_cipher == CIPHER_WARN) {
4100 /* If/when we choose a cipher, warn about it */
4102 } else if (next_cipher == CIPHER_AES) {
4103 /* XXX Probably don't need to mention this. */
4104 logevent("AES not supported in SSH-1, skipping");
4106 switch (next_cipher) {
4107 case CIPHER_3DES: s->cipher_type = SSH_CIPHER_3DES;
4108 cipher_string = "3DES"; break;
4109 case CIPHER_BLOWFISH: s->cipher_type = SSH_CIPHER_BLOWFISH;
4110 cipher_string = "Blowfish"; break;
4111 case CIPHER_DES: s->cipher_type = SSH_CIPHER_DES;
4112 cipher_string = "single-DES"; break;
4114 if (s->supported_ciphers_mask & (1 << s->cipher_type))
4118 if (!cipher_chosen) {
4119 if ((s->supported_ciphers_mask & (1 << SSH_CIPHER_3DES)) == 0)
4120 bombout(("Server violates SSH-1 protocol by not "
4121 "supporting 3DES encryption"));
4123 /* shouldn't happen */
4124 bombout(("No supported ciphers found"));
4128 /* Warn about chosen cipher if necessary. */
4130 ssh_set_frozen(ssh, 1);
4131 s->dlgret = askalg(ssh->frontend, "cipher", cipher_string,
4132 ssh_dialog_callback, ssh);
4133 if (s->dlgret < 0) {
4137 bombout(("Unexpected data from server while waiting"
4138 " for user response"));
4141 } while (pktin || inlen > 0);
4142 s->dlgret = ssh->user_response;
4144 ssh_set_frozen(ssh, 0);
4145 if (s->dlgret == 0) {
4146 ssh_disconnect(ssh, "User aborted at cipher warning", NULL,
4153 switch (s->cipher_type) {
4154 case SSH_CIPHER_3DES:
4155 logevent("Using 3DES encryption");
4157 case SSH_CIPHER_DES:
4158 logevent("Using single-DES encryption");
4160 case SSH_CIPHER_BLOWFISH:
4161 logevent("Using Blowfish encryption");
4165 send_packet(ssh, SSH1_CMSG_SESSION_KEY,
4166 PKT_CHAR, s->cipher_type,
4167 PKT_DATA, cookie, 8,
4168 PKT_CHAR, (s->len * 8) >> 8, PKT_CHAR, (s->len * 8) & 0xFF,
4169 PKT_DATA, s->rsabuf, s->len,
4170 PKT_INT, ssh->v1_local_protoflags, PKT_END);
4172 logevent("Trying to enable encryption...");
4176 ssh->cipher = (s->cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 :
4177 s->cipher_type == SSH_CIPHER_DES ? &ssh_des :
4179 ssh->v1_cipher_ctx = ssh->cipher->make_context();
4180 ssh->cipher->sesskey(ssh->v1_cipher_ctx, ssh->session_key);
4181 logeventf(ssh, "Initialised %s encryption", ssh->cipher->text_name);
4183 ssh->crcda_ctx = crcda_make_context();
4184 logevent("Installing CRC compensation attack detector");
4186 if (s->servkey.modulus) {
4187 sfree(s->servkey.modulus);
4188 s->servkey.modulus = NULL;
4190 if (s->servkey.exponent) {
4191 sfree(s->servkey.exponent);
4192 s->servkey.exponent = NULL;
4194 if (s->hostkey.modulus) {
4195 sfree(s->hostkey.modulus);
4196 s->hostkey.modulus = NULL;
4198 if (s->hostkey.exponent) {
4199 sfree(s->hostkey.exponent);
4200 s->hostkey.exponent = NULL;
4204 if (pktin->type != SSH1_SMSG_SUCCESS) {
4205 bombout(("Encryption not successfully enabled"));
4209 logevent("Successfully started encryption");
4211 fflush(stdout); /* FIXME eh? */
4213 if ((ssh->username = get_remote_username(ssh->conf)) == NULL) {
4214 int ret; /* need not be kept over crReturn */
4215 s->cur_prompt = new_prompts(ssh->frontend);
4216 s->cur_prompt->to_server = TRUE;
4217 s->cur_prompt->name = dupstr("SSH login name");
4218 add_prompt(s->cur_prompt, dupstr("login as: "), TRUE);
4219 ret = get_userpass_input(s->cur_prompt, NULL, 0);
4222 crWaitUntil(!pktin);
4223 ret = get_userpass_input(s->cur_prompt, in, inlen);
4228 * Failed to get a username. Terminate.
4230 free_prompts(s->cur_prompt);
4231 ssh_disconnect(ssh, "No username provided", NULL, 0, TRUE);
4234 ssh->username = dupstr(s->cur_prompt->prompts[0]->result);
4235 free_prompts(s->cur_prompt);
4238 send_packet(ssh, SSH1_CMSG_USER, PKT_STR, ssh->username, PKT_END);
4240 char *userlog = dupprintf("Sent username \"%s\"", ssh->username);
4242 if (flags & FLAG_INTERACTIVE &&
4243 (!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) {
4244 c_write_str(ssh, userlog);
4245 c_write_str(ssh, "\r\n");
4253 if ((s->supported_auths_mask & (1 << SSH1_AUTH_RSA)) == 0) {
4254 /* We must not attempt PK auth. Pretend we've already tried it. */
4255 s->tried_publickey = s->tried_agent = 1;
4257 s->tried_publickey = s->tried_agent = 0;
4259 s->tis_auth_refused = s->ccard_auth_refused = 0;
4261 * Load the public half of any configured keyfile for later use.
4263 s->keyfile = conf_get_filename(ssh->conf, CONF_keyfile);
4264 if (!filename_is_null(s->keyfile)) {
4266 logeventf(ssh, "Reading key file \"%.150s\"",
4267 filename_to_str(s->keyfile));
4268 keytype = key_type(s->keyfile);
4269 if (keytype == SSH_KEYTYPE_SSH1 ||
4270 keytype == SSH_KEYTYPE_SSH1_PUBLIC) {
4272 if (rsakey_pubblob(s->keyfile,
4273 &s->publickey_blob, &s->publickey_bloblen,
4274 &s->publickey_comment, &error)) {
4275 s->privatekey_available = (keytype == SSH_KEYTYPE_SSH1);
4276 if (!s->privatekey_available)
4277 logeventf(ssh, "Key file contains public key only");
4278 s->privatekey_encrypted = rsakey_encrypted(s->keyfile,
4282 logeventf(ssh, "Unable to load key (%s)", error);
4283 msgbuf = dupprintf("Unable to load key file "
4284 "\"%.150s\" (%s)\r\n",
4285 filename_to_str(s->keyfile),
4287 c_write_str(ssh, msgbuf);
4289 s->publickey_blob = NULL;
4293 logeventf(ssh, "Unable to use this key file (%s)",
4294 key_type_to_str(keytype));
4295 msgbuf = dupprintf("Unable to use key file \"%.150s\""
4297 filename_to_str(s->keyfile),
4298 key_type_to_str(keytype));
4299 c_write_str(ssh, msgbuf);
4301 s->publickey_blob = NULL;
4304 s->publickey_blob = NULL;
4306 while (pktin->type == SSH1_SMSG_FAILURE) {
4307 s->pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
4309 if (conf_get_int(ssh->conf, CONF_tryagent) && agent_exists() && !s->tried_agent) {
4311 * Attempt RSA authentication using Pageant.
4317 logevent("Pageant is running. Requesting keys.");
4319 /* Request the keys held by the agent. */
4320 PUT_32BIT(s->request, 1);
4321 s->request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES;
4322 if (!agent_query(s->request, 5, &r, &s->responselen,
4323 ssh_agent_callback, ssh)) {
4327 bombout(("Unexpected data from server while waiting"
4328 " for agent response"));
4331 } while (pktin || inlen > 0);
4332 r = ssh->agent_response;
4333 s->responselen = ssh->agent_response_len;
4335 s->response = (unsigned char *) r;
4336 if (s->response && s->responselen >= 5 &&
4337 s->response[4] == SSH1_AGENT_RSA_IDENTITIES_ANSWER) {
4338 s->p = s->response + 5;
4339 s->nkeys = toint(GET_32BIT(s->p));
4341 logeventf(ssh, "Pageant reported negative key count %d",
4346 logeventf(ssh, "Pageant has %d SSH-1 keys", s->nkeys);
4347 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
4348 unsigned char *pkblob = s->p;
4352 do { /* do while (0) to make breaking easy */
4353 n = ssh1_read_bignum
4354 (s->p, toint(s->responselen-(s->p-s->response)),
4359 n = ssh1_read_bignum
4360 (s->p, toint(s->responselen-(s->p-s->response)),
4365 if (s->responselen - (s->p-s->response) < 4)
4367 s->commentlen = toint(GET_32BIT(s->p));
4369 if (s->commentlen < 0 ||
4370 toint(s->responselen - (s->p-s->response)) <
4373 s->commentp = (char *)s->p;
4374 s->p += s->commentlen;
4378 logevent("Pageant key list packet was truncated");
4382 if (s->publickey_blob) {
4383 if (!memcmp(pkblob, s->publickey_blob,
4384 s->publickey_bloblen)) {
4385 logeventf(ssh, "Pageant key #%d matches "
4386 "configured key file", s->keyi);
4387 s->tried_publickey = 1;
4389 /* Skip non-configured key */
4392 logeventf(ssh, "Trying Pageant key #%d", s->keyi);
4393 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
4394 PKT_BIGNUM, s->key.modulus, PKT_END);
4396 if (pktin->type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
4397 logevent("Key refused");
4400 logevent("Received RSA challenge");
4401 if ((s->challenge = ssh1_pkt_getmp(pktin)) == NULL) {
4402 bombout(("Server's RSA challenge was badly formatted"));
4407 char *agentreq, *q, *ret;
4410 len = 1 + 4; /* message type, bit count */
4411 len += ssh1_bignum_length(s->key.exponent);
4412 len += ssh1_bignum_length(s->key.modulus);
4413 len += ssh1_bignum_length(s->challenge);
4414 len += 16; /* session id */
4415 len += 4; /* response format */
4416 agentreq = snewn(4 + len, char);
4417 PUT_32BIT(agentreq, len);
4419 *q++ = SSH1_AGENTC_RSA_CHALLENGE;
4420 PUT_32BIT(q, bignum_bitcount(s->key.modulus));
4422 q += ssh1_write_bignum(q, s->key.exponent);
4423 q += ssh1_write_bignum(q, s->key.modulus);
4424 q += ssh1_write_bignum(q, s->challenge);
4425 memcpy(q, s->session_id, 16);
4427 PUT_32BIT(q, 1); /* response format */
4428 if (!agent_query(agentreq, len + 4, &vret, &retlen,
4429 ssh_agent_callback, ssh)) {
4434 bombout(("Unexpected data from server"
4435 " while waiting for agent"
4439 } while (pktin || inlen > 0);
4440 vret = ssh->agent_response;
4441 retlen = ssh->agent_response_len;
4446 if (ret[4] == SSH1_AGENT_RSA_RESPONSE) {
4447 logevent("Sending Pageant's response");
4448 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
4449 PKT_DATA, ret + 5, 16,
4453 if (pktin->type == SSH1_SMSG_SUCCESS) {
4455 ("Pageant's response accepted");
4456 if (flags & FLAG_VERBOSE) {
4457 c_write_str(ssh, "Authenticated using"
4459 c_write(ssh, s->commentp,
4461 c_write_str(ssh, "\" from agent\r\n");
4466 ("Pageant's response not accepted");
4469 ("Pageant failed to answer challenge");
4473 logevent("No reply received from Pageant");
4476 freebn(s->key.exponent);
4477 freebn(s->key.modulus);
4478 freebn(s->challenge);
4483 if (s->publickey_blob && !s->tried_publickey)
4484 logevent("Configured key file not in Pageant");
4486 logevent("Failed to get reply from Pageant");
4491 if (s->publickey_blob && s->privatekey_available &&
4492 !s->tried_publickey) {
4494 * Try public key authentication with the specified
4497 int got_passphrase; /* need not be kept over crReturn */
4498 if (flags & FLAG_VERBOSE)
4499 c_write_str(ssh, "Trying public key authentication.\r\n");
4500 s->keyfile = conf_get_filename(ssh->conf, CONF_keyfile);
4501 logeventf(ssh, "Trying public key \"%s\"",
4502 filename_to_str(s->keyfile));
4503 s->tried_publickey = 1;
4504 got_passphrase = FALSE;
4505 while (!got_passphrase) {
4507 * Get a passphrase, if necessary.
4509 char *passphrase = NULL; /* only written after crReturn */
4511 if (!s->privatekey_encrypted) {
4512 if (flags & FLAG_VERBOSE)
4513 c_write_str(ssh, "No passphrase required.\r\n");
4516 int ret; /* need not be kept over crReturn */
4517 s->cur_prompt = new_prompts(ssh->frontend);
4518 s->cur_prompt->to_server = FALSE;
4519 s->cur_prompt->name = dupstr("SSH key passphrase");
4520 add_prompt(s->cur_prompt,
4521 dupprintf("Passphrase for key \"%.100s\": ",
4522 s->publickey_comment), FALSE);
4523 ret = get_userpass_input(s->cur_prompt, NULL, 0);
4526 crWaitUntil(!pktin);
4527 ret = get_userpass_input(s->cur_prompt, in, inlen);
4531 /* Failed to get a passphrase. Terminate. */
4532 free_prompts(s->cur_prompt);
4533 ssh_disconnect(ssh, NULL, "Unable to authenticate",
4537 passphrase = dupstr(s->cur_prompt->prompts[0]->result);
4538 free_prompts(s->cur_prompt);
4541 * Try decrypting key with passphrase.
4543 s->keyfile = conf_get_filename(ssh->conf, CONF_keyfile);
4544 ret = loadrsakey(s->keyfile, &s->key, passphrase,
4547 smemclr(passphrase, strlen(passphrase));
4551 /* Correct passphrase. */
4552 got_passphrase = TRUE;
4553 } else if (ret == 0) {
4554 c_write_str(ssh, "Couldn't load private key from ");
4555 c_write_str(ssh, filename_to_str(s->keyfile));
4556 c_write_str(ssh, " (");
4557 c_write_str(ssh, error);
4558 c_write_str(ssh, ").\r\n");
4559 got_passphrase = FALSE;
4560 break; /* go and try something else */
4561 } else if (ret == -1) {
4562 c_write_str(ssh, "Wrong passphrase.\r\n"); /* FIXME */
4563 got_passphrase = FALSE;
4566 assert(0 && "unexpected return from loadrsakey()");
4567 got_passphrase = FALSE; /* placate optimisers */
4571 if (got_passphrase) {
4574 * Send a public key attempt.
4576 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
4577 PKT_BIGNUM, s->key.modulus, PKT_END);
4580 if (pktin->type == SSH1_SMSG_FAILURE) {
4581 c_write_str(ssh, "Server refused our public key.\r\n");
4582 continue; /* go and try something else */
4584 if (pktin->type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
4585 bombout(("Bizarre response to offer of public key"));
4591 unsigned char buffer[32];
4592 Bignum challenge, response;
4594 if ((challenge = ssh1_pkt_getmp(pktin)) == NULL) {
4595 bombout(("Server's RSA challenge was badly formatted"));
4598 response = rsadecrypt(challenge, &s->key);
4599 freebn(s->key.private_exponent);/* burn the evidence */
4601 for (i = 0; i < 32; i++) {
4602 buffer[i] = bignum_byte(response, 31 - i);
4606 MD5Update(&md5c, buffer, 32);
4607 MD5Update(&md5c, s->session_id, 16);
4608 MD5Final(buffer, &md5c);
4610 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
4611 PKT_DATA, buffer, 16, PKT_END);
4618 if (pktin->type == SSH1_SMSG_FAILURE) {
4619 if (flags & FLAG_VERBOSE)
4620 c_write_str(ssh, "Failed to authenticate with"
4621 " our public key.\r\n");
4622 continue; /* go and try something else */
4623 } else if (pktin->type != SSH1_SMSG_SUCCESS) {
4624 bombout(("Bizarre response to RSA authentication response"));
4628 break; /* we're through! */
4634 * Otherwise, try various forms of password-like authentication.
4636 s->cur_prompt = new_prompts(ssh->frontend);
4638 if (conf_get_int(ssh->conf, CONF_try_tis_auth) &&
4639 (s->supported_auths_mask & (1 << SSH1_AUTH_TIS)) &&
4640 !s->tis_auth_refused) {
4641 s->pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
4642 logevent("Requested TIS authentication");
4643 send_packet(ssh, SSH1_CMSG_AUTH_TIS, PKT_END);
4645 if (pktin->type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
4646 logevent("TIS authentication declined");
4647 if (flags & FLAG_INTERACTIVE)
4648 c_write_str(ssh, "TIS authentication refused.\r\n");
4649 s->tis_auth_refused = 1;
4654 char *instr_suf, *prompt;
4656 ssh_pkt_getstring(pktin, &challenge, &challengelen);
4658 bombout(("TIS challenge packet was badly formed"));
4661 logevent("Received TIS challenge");
4662 s->cur_prompt->to_server = TRUE;
4663 s->cur_prompt->name = dupstr("SSH TIS authentication");
4664 /* Prompt heuristic comes from OpenSSH */
4665 if (memchr(challenge, '\n', challengelen)) {
4666 instr_suf = dupstr("");
4667 prompt = dupprintf("%.*s", challengelen, challenge);
4669 instr_suf = dupprintf("%.*s", challengelen, challenge);
4670 prompt = dupstr("Response: ");
4672 s->cur_prompt->instruction =
4673 dupprintf("Using TIS authentication.%s%s",
4674 (*instr_suf) ? "\n" : "",
4676 s->cur_prompt->instr_reqd = TRUE;
4677 add_prompt(s->cur_prompt, prompt, FALSE);
4681 if (conf_get_int(ssh->conf, CONF_try_tis_auth) &&
4682 (s->supported_auths_mask & (1 << SSH1_AUTH_CCARD)) &&
4683 !s->ccard_auth_refused) {
4684 s->pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE;
4685 logevent("Requested CryptoCard authentication");
4686 send_packet(ssh, SSH1_CMSG_AUTH_CCARD, PKT_END);
4688 if (pktin->type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
4689 logevent("CryptoCard authentication declined");
4690 c_write_str(ssh, "CryptoCard authentication refused.\r\n");
4691 s->ccard_auth_refused = 1;
4696 char *instr_suf, *prompt;
4698 ssh_pkt_getstring(pktin, &challenge, &challengelen);
4700 bombout(("CryptoCard challenge packet was badly formed"));
4703 logevent("Received CryptoCard challenge");
4704 s->cur_prompt->to_server = TRUE;
4705 s->cur_prompt->name = dupstr("SSH CryptoCard authentication");
4706 s->cur_prompt->name_reqd = FALSE;
4707 /* Prompt heuristic comes from OpenSSH */
4708 if (memchr(challenge, '\n', challengelen)) {
4709 instr_suf = dupstr("");
4710 prompt = dupprintf("%.*s", challengelen, challenge);
4712 instr_suf = dupprintf("%.*s", challengelen, challenge);
4713 prompt = dupstr("Response: ");
4715 s->cur_prompt->instruction =
4716 dupprintf("Using CryptoCard authentication.%s%s",
4717 (*instr_suf) ? "\n" : "",
4719 s->cur_prompt->instr_reqd = TRUE;
4720 add_prompt(s->cur_prompt, prompt, FALSE);
4724 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
4725 if ((s->supported_auths_mask & (1 << SSH1_AUTH_PASSWORD)) == 0) {
4726 bombout(("No supported authentication methods available"));
4729 s->cur_prompt->to_server = TRUE;
4730 s->cur_prompt->name = dupstr("SSH password");
4731 add_prompt(s->cur_prompt, dupprintf("%s@%s's password: ",
4732 ssh->username, ssh->savedhost),
4737 * Show password prompt, having first obtained it via a TIS
4738 * or CryptoCard exchange if we're doing TIS or CryptoCard
4742 int ret; /* need not be kept over crReturn */
4743 ret = get_userpass_input(s->cur_prompt, NULL, 0);
4746 crWaitUntil(!pktin);
4747 ret = get_userpass_input(s->cur_prompt, in, inlen);
4752 * Failed to get a password (for example
4753 * because one was supplied on the command line
4754 * which has already failed to work). Terminate.
4756 free_prompts(s->cur_prompt);
4757 ssh_disconnect(ssh, NULL, "Unable to authenticate", 0, TRUE);
4762 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
4764 * Defence against traffic analysis: we send a
4765 * whole bunch of packets containing strings of
4766 * different lengths. One of these strings is the
4767 * password, in a SSH1_CMSG_AUTH_PASSWORD packet.
4768 * The others are all random data in
4769 * SSH1_MSG_IGNORE packets. This way a passive
4770 * listener can't tell which is the password, and
4771 * hence can't deduce the password length.
4773 * Anybody with a password length greater than 16
4774 * bytes is going to have enough entropy in their
4775 * password that a listener won't find it _that_
4776 * much help to know how long it is. So what we'll
4779 * - if password length < 16, we send 15 packets
4780 * containing string lengths 1 through 15
4782 * - otherwise, we let N be the nearest multiple
4783 * of 8 below the password length, and send 8
4784 * packets containing string lengths N through
4785 * N+7. This won't obscure the order of
4786 * magnitude of the password length, but it will
4787 * introduce a bit of extra uncertainty.
4789 * A few servers can't deal with SSH1_MSG_IGNORE, at
4790 * least in this context. For these servers, we need
4791 * an alternative defence. We make use of the fact
4792 * that the password is interpreted as a C string:
4793 * so we can append a NUL, then some random data.
4795 * A few servers can deal with neither SSH1_MSG_IGNORE
4796 * here _nor_ a padded password string.
4797 * For these servers we are left with no defences
4798 * against password length sniffing.
4800 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE) &&
4801 !(ssh->remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) {
4803 * The server can deal with SSH1_MSG_IGNORE, so
4804 * we can use the primary defence.
4806 int bottom, top, pwlen, i;
4809 pwlen = strlen(s->cur_prompt->prompts[0]->result);
4811 bottom = 0; /* zero length passwords are OK! :-) */
4814 bottom = pwlen & ~7;
4818 assert(pwlen >= bottom && pwlen <= top);
4820 randomstr = snewn(top + 1, char);
4822 for (i = bottom; i <= top; i++) {
4824 defer_packet(ssh, s->pwpkt_type,
4825 PKT_STR,s->cur_prompt->prompts[0]->result,
4828 for (j = 0; j < i; j++) {
4830 randomstr[j] = random_byte();
4831 } while (randomstr[j] == '\0');
4833 randomstr[i] = '\0';
4834 defer_packet(ssh, SSH1_MSG_IGNORE,
4835 PKT_STR, randomstr, PKT_END);
4838 logevent("Sending password with camouflage packets");
4839 ssh_pkt_defersend(ssh);
4842 else if (!(ssh->remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) {
4844 * The server can't deal with SSH1_MSG_IGNORE
4845 * but can deal with padded passwords, so we
4846 * can use the secondary defence.
4852 len = strlen(s->cur_prompt->prompts[0]->result);
4853 if (len < sizeof(string)) {
4855 strcpy(string, s->cur_prompt->prompts[0]->result);
4856 len++; /* cover the zero byte */
4857 while (len < sizeof(string)) {
4858 string[len++] = (char) random_byte();
4861 ss = s->cur_prompt->prompts[0]->result;
4863 logevent("Sending length-padded password");
4864 send_packet(ssh, s->pwpkt_type,
4865 PKT_INT, len, PKT_DATA, ss, len,
4869 * The server is believed unable to cope with
4870 * any of our password camouflage methods.
4873 len = strlen(s->cur_prompt->prompts[0]->result);
4874 logevent("Sending unpadded password");
4875 send_packet(ssh, s->pwpkt_type,
4877 PKT_DATA, s->cur_prompt->prompts[0]->result, len,
4881 send_packet(ssh, s->pwpkt_type,
4882 PKT_STR, s->cur_prompt->prompts[0]->result,
4885 logevent("Sent password");
4886 free_prompts(s->cur_prompt);
4888 if (pktin->type == SSH1_SMSG_FAILURE) {
4889 if (flags & FLAG_VERBOSE)
4890 c_write_str(ssh, "Access denied\r\n");
4891 logevent("Authentication refused");
4892 } else if (pktin->type != SSH1_SMSG_SUCCESS) {
4893 bombout(("Strange packet received, type %d", pktin->type));
4899 if (s->publickey_blob) {
4900 sfree(s->publickey_blob);
4901 sfree(s->publickey_comment);
4904 logevent("Authentication successful");
4909 static void ssh_channel_try_eof(struct ssh_channel *c)
4912 assert(c->pending_eof); /* precondition for calling us */
4914 return; /* can't close: not even opened yet */
4915 if (ssh->version == 2 && bufchain_size(&c->v.v2.outbuffer) > 0)
4916 return; /* can't send EOF: pending outgoing data */
4918 c->pending_eof = FALSE; /* we're about to send it */
4919 if (ssh->version == 1) {
4920 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid,
4922 c->closes |= CLOSES_SENT_EOF;
4924 struct Packet *pktout;
4925 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_EOF);
4926 ssh2_pkt_adduint32(pktout, c->remoteid);
4927 ssh2_pkt_send(ssh, pktout);
4928 c->closes |= CLOSES_SENT_EOF;
4929 ssh2_channel_check_close(c);
4933 Conf *sshfwd_get_conf(struct ssh_channel *c)
4939 void sshfwd_write_eof(struct ssh_channel *c)
4943 if (ssh->state == SSH_STATE_CLOSED)
4946 if (c->closes & CLOSES_SENT_EOF)
4949 c->pending_eof = TRUE;
4950 ssh_channel_try_eof(c);
4953 void sshfwd_unclean_close(struct ssh_channel *c, const char *err)
4957 if (ssh->state == SSH_STATE_CLOSED)
4962 x11_close(c->u.x11.xconn);
4963 logeventf(ssh, "Forwarded X11 connection terminated due to local "
4967 case CHAN_SOCKDATA_DORMANT:
4968 pfd_close(c->u.pfd.pf);
4969 logeventf(ssh, "Forwarded port closed due to local error: %s", err);
4972 c->type = CHAN_ZOMBIE;
4973 c->pending_eof = FALSE; /* this will confuse a zombie channel */
4975 ssh2_channel_check_close(c);
4978 int sshfwd_write(struct ssh_channel *c, char *buf, int len)
4982 if (ssh->state == SSH_STATE_CLOSED)
4985 if (ssh->version == 1) {
4986 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
4987 PKT_INT, c->remoteid,
4988 PKT_INT, len, PKT_DATA, buf, len,
4991 * In SSH-1 we can return 0 here - implying that forwarded
4992 * connections are never individually throttled - because
4993 * the only circumstance that can cause throttling will be
4994 * the whole SSH connection backing up, in which case
4995 * _everything_ will be throttled as a whole.
4999 ssh2_add_channel_data(c, buf, len);
5000 return ssh2_try_send(c);
5004 void sshfwd_unthrottle(struct ssh_channel *c, int bufsize)
5009 if (ssh->state == SSH_STATE_CLOSED)
5012 if (ssh->version == 1) {
5013 buflimit = SSH1_BUFFER_LIMIT;
5015 buflimit = c->v.v2.locmaxwin;
5016 ssh2_set_window(c, bufsize < buflimit ? buflimit - bufsize : 0);
5018 if (c->throttling_conn && bufsize <= buflimit) {
5019 c->throttling_conn = 0;
5020 ssh_throttle_conn(ssh, -1);
5024 static void ssh_queueing_handler(Ssh ssh, struct Packet *pktin)
5026 struct queued_handler *qh = ssh->qhead;
5030 assert(pktin->type == qh->msg1 || pktin->type == qh->msg2);
5033 assert(ssh->packet_dispatch[qh->msg1] == ssh_queueing_handler);
5034 ssh->packet_dispatch[qh->msg1] = ssh->q_saved_handler1;
5037 assert(ssh->packet_dispatch[qh->msg2] == ssh_queueing_handler);
5038 ssh->packet_dispatch[qh->msg2] = ssh->q_saved_handler2;
5042 ssh->qhead = qh->next;
5044 if (ssh->qhead->msg1 > 0) {
5045 ssh->q_saved_handler1 = ssh->packet_dispatch[ssh->qhead->msg1];
5046 ssh->packet_dispatch[ssh->qhead->msg1] = ssh_queueing_handler;
5048 if (ssh->qhead->msg2 > 0) {
5049 ssh->q_saved_handler2 = ssh->packet_dispatch[ssh->qhead->msg2];
5050 ssh->packet_dispatch[ssh->qhead->msg2] = ssh_queueing_handler;
5053 ssh->qhead = ssh->qtail = NULL;
5056 qh->handler(ssh, pktin, qh->ctx);
5061 static void ssh_queue_handler(Ssh ssh, int msg1, int msg2,
5062 chandler_fn_t handler, void *ctx)
5064 struct queued_handler *qh;
5066 qh = snew(struct queued_handler);
5069 qh->handler = handler;
5073 if (ssh->qtail == NULL) {
5077 ssh->q_saved_handler1 = ssh->packet_dispatch[ssh->qhead->msg1];
5078 ssh->packet_dispatch[qh->msg1] = ssh_queueing_handler;
5081 ssh->q_saved_handler2 = ssh->packet_dispatch[ssh->qhead->msg2];
5082 ssh->packet_dispatch[qh->msg2] = ssh_queueing_handler;
5085 ssh->qtail->next = qh;
5090 static void ssh_rportfwd_succfail(Ssh ssh, struct Packet *pktin, void *ctx)
5092 struct ssh_rportfwd *rpf, *pf = (struct ssh_rportfwd *)ctx;
5094 if (pktin->type == (ssh->version == 1 ? SSH1_SMSG_SUCCESS :
5095 SSH2_MSG_REQUEST_SUCCESS)) {
5096 logeventf(ssh, "Remote port forwarding from %s enabled",
5099 logeventf(ssh, "Remote port forwarding from %s refused",
5102 rpf = del234(ssh->rportfwds, pf);
5104 pf->pfrec->remote = NULL;
5109 int ssh_alloc_sharing_rportfwd(Ssh ssh, const char *shost, int sport,
5112 struct ssh_rportfwd *pf = snew(struct ssh_rportfwd);
5115 pf->share_ctx = share_ctx;
5116 pf->shost = dupstr(shost);
5118 pf->sportdesc = NULL;
5119 if (!ssh->rportfwds) {
5120 assert(ssh->version == 2);
5121 ssh->rportfwds = newtree234(ssh_rportcmp_ssh2);
5123 if (add234(ssh->rportfwds, pf) != pf) {
5131 static void ssh_sharing_global_request_response(Ssh ssh, struct Packet *pktin,
5134 share_got_pkt_from_server(ctx, pktin->type,
5135 pktin->body, pktin->length);
5138 void ssh_sharing_queue_global_request(Ssh ssh, void *share_ctx)
5140 ssh_queue_handler(ssh, SSH2_MSG_REQUEST_SUCCESS, SSH2_MSG_REQUEST_FAILURE,
5141 ssh_sharing_global_request_response, share_ctx);
5144 static void ssh_setup_portfwd(Ssh ssh, Conf *conf)
5146 struct ssh_portfwd *epf;
5150 if (!ssh->portfwds) {
5151 ssh->portfwds = newtree234(ssh_portcmp);
5154 * Go through the existing port forwardings and tag them
5155 * with status==DESTROY. Any that we want to keep will be
5156 * re-enabled (status==KEEP) as we go through the
5157 * configuration and find out which bits are the same as
5160 struct ssh_portfwd *epf;
5162 for (i = 0; (epf = index234(ssh->portfwds, i)) != NULL; i++)
5163 epf->status = DESTROY;
5166 for (val = conf_get_str_strs(conf, CONF_portfwd, NULL, &key);
5168 val = conf_get_str_strs(conf, CONF_portfwd, key, &key)) {
5169 char *kp, *kp2, *vp, *vp2;
5170 char address_family, type;
5171 int sport,dport,sserv,dserv;
5172 char *sports, *dports, *saddr, *host;
5176 address_family = 'A';
5178 if (*kp == 'A' || *kp == '4' || *kp == '6')
5179 address_family = *kp++;
5180 if (*kp == 'L' || *kp == 'R')
5183 if ((kp2 = host_strchr(kp, ':')) != NULL) {
5185 * There's a colon in the middle of the source port
5186 * string, which means that the part before it is
5187 * actually a source address.
5189 char *saddr_tmp = dupprintf("%.*s", (int)(kp2 - kp), kp);
5190 saddr = host_strduptrim(saddr_tmp);
5197 sport = atoi(sports);
5201 sport = net_service_lookup(sports);
5203 logeventf(ssh, "Service lookup failed for source"
5204 " port \"%s\"", sports);
5208 if (type == 'L' && !strcmp(val, "D")) {
5209 /* dynamic forwarding */
5216 /* ordinary forwarding */
5218 vp2 = vp + host_strcspn(vp, ":");
5219 host = dupprintf("%.*s", (int)(vp2 - vp), vp);
5223 dport = atoi(dports);
5227 dport = net_service_lookup(dports);
5229 logeventf(ssh, "Service lookup failed for destination"
5230 " port \"%s\"", dports);
5235 if (sport && dport) {
5236 /* Set up a description of the source port. */
5237 struct ssh_portfwd *pfrec, *epfrec;
5239 pfrec = snew(struct ssh_portfwd);
5241 pfrec->saddr = saddr;
5242 pfrec->sserv = sserv ? dupstr(sports) : NULL;
5243 pfrec->sport = sport;
5244 pfrec->daddr = host;
5245 pfrec->dserv = dserv ? dupstr(dports) : NULL;
5246 pfrec->dport = dport;
5247 pfrec->local = NULL;
5248 pfrec->remote = NULL;
5249 pfrec->addressfamily = (address_family == '4' ? ADDRTYPE_IPV4 :
5250 address_family == '6' ? ADDRTYPE_IPV6 :
5253 epfrec = add234(ssh->portfwds, pfrec);
5254 if (epfrec != pfrec) {
5255 if (epfrec->status == DESTROY) {
5257 * We already have a port forwarding up and running
5258 * with precisely these parameters. Hence, no need
5259 * to do anything; simply re-tag the existing one
5262 epfrec->status = KEEP;
5265 * Anything else indicates that there was a duplicate
5266 * in our input, which we'll silently ignore.
5268 free_portfwd(pfrec);
5270 pfrec->status = CREATE;
5279 * Now go through and destroy any port forwardings which were
5282 for (i = 0; (epf = index234(ssh->portfwds, i)) != NULL; i++)
5283 if (epf->status == DESTROY) {
5286 message = dupprintf("%s port forwarding from %s%s%d",
5287 epf->type == 'L' ? "local" :
5288 epf->type == 'R' ? "remote" : "dynamic",
5289 epf->saddr ? epf->saddr : "",
5290 epf->saddr ? ":" : "",
5293 if (epf->type != 'D') {
5294 char *msg2 = dupprintf("%s to %s:%d", message,
5295 epf->daddr, epf->dport);
5300 logeventf(ssh, "Cancelling %s", message);
5303 /* epf->remote or epf->local may be NULL if setting up a
5304 * forwarding failed. */
5306 struct ssh_rportfwd *rpf = epf->remote;
5307 struct Packet *pktout;
5310 * Cancel the port forwarding at the server
5313 if (ssh->version == 1) {
5315 * We cannot cancel listening ports on the
5316 * server side in SSH-1! There's no message
5317 * to support it. Instead, we simply remove
5318 * the rportfwd record from the local end
5319 * so that any connections the server tries
5320 * to make on it are rejected.
5323 pktout = ssh2_pkt_init(SSH2_MSG_GLOBAL_REQUEST);
5324 ssh2_pkt_addstring(pktout, "cancel-tcpip-forward");
5325 ssh2_pkt_addbool(pktout, 0);/* _don't_ want reply */
5327 ssh2_pkt_addstring(pktout, epf->saddr);
5328 } else if (conf_get_int(conf, CONF_rport_acceptall)) {
5329 /* XXX: rport_acceptall may not represent
5330 * what was used to open the original connection,
5331 * since it's reconfigurable. */
5332 ssh2_pkt_addstring(pktout, "");
5334 ssh2_pkt_addstring(pktout, "localhost");
5336 ssh2_pkt_adduint32(pktout, epf->sport);
5337 ssh2_pkt_send(ssh, pktout);
5340 del234(ssh->rportfwds, rpf);
5342 } else if (epf->local) {
5343 pfl_terminate(epf->local);
5346 delpos234(ssh->portfwds, i);
5348 i--; /* so we don't skip one in the list */
5352 * And finally, set up any new port forwardings (status==CREATE).
5354 for (i = 0; (epf = index234(ssh->portfwds, i)) != NULL; i++)
5355 if (epf->status == CREATE) {
5356 char *sportdesc, *dportdesc;
5357 sportdesc = dupprintf("%s%s%s%s%d%s",
5358 epf->saddr ? epf->saddr : "",
5359 epf->saddr ? ":" : "",
5360 epf->sserv ? epf->sserv : "",
5361 epf->sserv ? "(" : "",
5363 epf->sserv ? ")" : "");
5364 if (epf->type == 'D') {
5367 dportdesc = dupprintf("%s:%s%s%d%s",
5369 epf->dserv ? epf->dserv : "",
5370 epf->dserv ? "(" : "",
5372 epf->dserv ? ")" : "");
5375 if (epf->type == 'L') {
5376 char *err = pfl_listen(epf->daddr, epf->dport,
5377 epf->saddr, epf->sport,
5378 ssh, conf, &epf->local,
5379 epf->addressfamily);
5381 logeventf(ssh, "Local %sport %s forwarding to %s%s%s",
5382 epf->addressfamily == ADDRTYPE_IPV4 ? "IPv4 " :
5383 epf->addressfamily == ADDRTYPE_IPV6 ? "IPv6 " : "",
5384 sportdesc, dportdesc,
5385 err ? " failed: " : "", err ? err : "");
5388 } else if (epf->type == 'D') {
5389 char *err = pfl_listen(NULL, -1, epf->saddr, epf->sport,
5390 ssh, conf, &epf->local,
5391 epf->addressfamily);
5393 logeventf(ssh, "Local %sport %s SOCKS dynamic forwarding%s%s",
5394 epf->addressfamily == ADDRTYPE_IPV4 ? "IPv4 " :
5395 epf->addressfamily == ADDRTYPE_IPV6 ? "IPv6 " : "",
5397 err ? " failed: " : "", err ? err : "");
5402 struct ssh_rportfwd *pf;
5405 * Ensure the remote port forwardings tree exists.
5407 if (!ssh->rportfwds) {
5408 if (ssh->version == 1)
5409 ssh->rportfwds = newtree234(ssh_rportcmp_ssh1);
5411 ssh->rportfwds = newtree234(ssh_rportcmp_ssh2);
5414 pf = snew(struct ssh_rportfwd);
5415 pf->share_ctx = NULL;
5416 pf->dhost = dupstr(epf->daddr);
5417 pf->dport = epf->dport;
5419 pf->shost = dupstr(epf->saddr);
5420 } else if (conf_get_int(conf, CONF_rport_acceptall)) {
5421 pf->shost = dupstr("");
5423 pf->shost = dupstr("localhost");
5425 pf->sport = epf->sport;
5426 if (add234(ssh->rportfwds, pf) != pf) {
5427 logeventf(ssh, "Duplicate remote port forwarding to %s:%d",
5428 epf->daddr, epf->dport);
5431 logeventf(ssh, "Requesting remote port %s"
5432 " forward to %s", sportdesc, dportdesc);
5434 pf->sportdesc = sportdesc;
5439 if (ssh->version == 1) {
5440 send_packet(ssh, SSH1_CMSG_PORT_FORWARD_REQUEST,
5441 PKT_INT, epf->sport,
5442 PKT_STR, epf->daddr,
5443 PKT_INT, epf->dport,
5445 ssh_queue_handler(ssh, SSH1_SMSG_SUCCESS,
5447 ssh_rportfwd_succfail, pf);
5449 struct Packet *pktout;
5450 pktout = ssh2_pkt_init(SSH2_MSG_GLOBAL_REQUEST);
5451 ssh2_pkt_addstring(pktout, "tcpip-forward");
5452 ssh2_pkt_addbool(pktout, 1);/* want reply */
5453 ssh2_pkt_addstring(pktout, pf->shost);
5454 ssh2_pkt_adduint32(pktout, pf->sport);
5455 ssh2_pkt_send(ssh, pktout);
5457 ssh_queue_handler(ssh, SSH2_MSG_REQUEST_SUCCESS,
5458 SSH2_MSG_REQUEST_FAILURE,
5459 ssh_rportfwd_succfail, pf);
5468 static void ssh1_smsg_stdout_stderr_data(Ssh ssh, struct Packet *pktin)
5471 int stringlen, bufsize;
5473 ssh_pkt_getstring(pktin, &string, &stringlen);
5474 if (string == NULL) {
5475 bombout(("Incoming terminal data packet was badly formed"));
5479 bufsize = from_backend(ssh->frontend, pktin->type == SSH1_SMSG_STDERR_DATA,
5481 if (!ssh->v1_stdout_throttling && bufsize > SSH1_BUFFER_LIMIT) {
5482 ssh->v1_stdout_throttling = 1;
5483 ssh_throttle_conn(ssh, +1);
5487 static void ssh1_smsg_x11_open(Ssh ssh, struct Packet *pktin)
5489 /* Remote side is trying to open a channel to talk to our
5490 * X-Server. Give them back a local channel number. */
5491 struct ssh_channel *c;
5492 int remoteid = ssh_pkt_getuint32(pktin);
5494 logevent("Received X11 connect request");
5495 /* Refuse if X11 forwarding is disabled. */
5496 if (!ssh->X11_fwd_enabled) {
5497 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
5498 PKT_INT, remoteid, PKT_END);
5499 logevent("Rejected X11 connect request");
5501 c = snew(struct ssh_channel);
5504 c->u.x11.xconn = x11_init(ssh->x11authtree, c, NULL, -1);
5505 c->remoteid = remoteid;
5506 c->halfopen = FALSE;
5507 c->localid = alloc_channel_id(ssh);
5509 c->pending_eof = FALSE;
5510 c->throttling_conn = 0;
5511 c->type = CHAN_X11; /* identify channel type */
5512 add234(ssh->channels, c);
5513 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
5514 PKT_INT, c->remoteid, PKT_INT,
5515 c->localid, PKT_END);
5516 logevent("Opened X11 forward channel");
5520 static void ssh1_smsg_agent_open(Ssh ssh, struct Packet *pktin)
5522 /* Remote side is trying to open a channel to talk to our
5523 * agent. Give them back a local channel number. */
5524 struct ssh_channel *c;
5525 int remoteid = ssh_pkt_getuint32(pktin);
5527 /* Refuse if agent forwarding is disabled. */
5528 if (!ssh->agentfwd_enabled) {
5529 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
5530 PKT_INT, remoteid, PKT_END);
5532 c = snew(struct ssh_channel);
5534 c->remoteid = remoteid;
5535 c->halfopen = FALSE;
5536 c->localid = alloc_channel_id(ssh);
5538 c->pending_eof = FALSE;
5539 c->throttling_conn = 0;
5540 c->type = CHAN_AGENT; /* identify channel type */
5541 c->u.a.lensofar = 0;
5542 c->u.a.message = NULL;
5543 c->u.a.outstanding_requests = 0;
5544 add234(ssh->channels, c);
5545 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
5546 PKT_INT, c->remoteid, PKT_INT, c->localid,
5551 static void ssh1_msg_port_open(Ssh ssh, struct Packet *pktin)
5553 /* Remote side is trying to open a channel to talk to a
5554 * forwarded port. Give them back a local channel number. */
5555 struct ssh_rportfwd pf, *pfp;
5561 remoteid = ssh_pkt_getuint32(pktin);
5562 ssh_pkt_getstring(pktin, &host, &hostsize);
5563 port = ssh_pkt_getuint32(pktin);
5565 pf.dhost = dupprintf("%.*s", hostsize, host);
5567 pfp = find234(ssh->rportfwds, &pf, NULL);
5570 logeventf(ssh, "Rejected remote port open request for %s:%d",
5572 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
5573 PKT_INT, remoteid, PKT_END);
5575 struct ssh_channel *c = snew(struct ssh_channel);
5578 logeventf(ssh, "Received remote port open request for %s:%d",
5580 err = pfd_connect(&c->u.pfd.pf, pf.dhost, port,
5581 c, ssh->conf, pfp->pfrec->addressfamily);
5583 logeventf(ssh, "Port open failed: %s", err);
5586 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
5587 PKT_INT, remoteid, PKT_END);
5589 c->remoteid = remoteid;
5590 c->halfopen = FALSE;
5591 c->localid = alloc_channel_id(ssh);
5593 c->pending_eof = FALSE;
5594 c->throttling_conn = 0;
5595 c->type = CHAN_SOCKDATA; /* identify channel type */
5596 add234(ssh->channels, c);
5597 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
5598 PKT_INT, c->remoteid, PKT_INT,
5599 c->localid, PKT_END);
5600 logevent("Forwarded port opened successfully");
5607 static void ssh1_msg_channel_open_confirmation(Ssh ssh, struct Packet *pktin)
5609 unsigned int remoteid = ssh_pkt_getuint32(pktin);
5610 unsigned int localid = ssh_pkt_getuint32(pktin);
5611 struct ssh_channel *c;
5613 c = find234(ssh->channels, &remoteid, ssh_channelfind);
5614 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
5615 c->remoteid = localid;
5616 c->halfopen = FALSE;
5617 c->type = CHAN_SOCKDATA;
5618 c->throttling_conn = 0;
5619 pfd_confirm(c->u.pfd.pf);
5622 if (c && c->pending_eof) {
5624 * We have a pending close on this channel,
5625 * which we decided on before the server acked
5626 * the channel open. So now we know the
5627 * remoteid, we can close it again.
5629 ssh_channel_try_eof(c);
5633 static void ssh1_msg_channel_open_failure(Ssh ssh, struct Packet *pktin)
5635 unsigned int remoteid = ssh_pkt_getuint32(pktin);
5636 struct ssh_channel *c;
5638 c = find234(ssh->channels, &remoteid, ssh_channelfind);
5639 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
5640 logevent("Forwarded connection refused by server");
5641 pfd_close(c->u.pfd.pf);
5642 del234(ssh->channels, c);
5647 static void ssh1_msg_channel_close(Ssh ssh, struct Packet *pktin)
5649 /* Remote side closes a channel. */
5650 unsigned i = ssh_pkt_getuint32(pktin);
5651 struct ssh_channel *c;
5652 c = find234(ssh->channels, &i, ssh_channelfind);
5653 if (c && !c->halfopen) {
5655 if (pktin->type == SSH1_MSG_CHANNEL_CLOSE &&
5656 !(c->closes & CLOSES_RCVD_EOF)) {
5658 * Received CHANNEL_CLOSE, which we translate into
5661 int send_close = FALSE;
5663 c->closes |= CLOSES_RCVD_EOF;
5668 x11_send_eof(c->u.x11.xconn);
5674 pfd_send_eof(c->u.pfd.pf);
5683 if (send_close && !(c->closes & CLOSES_SENT_EOF)) {
5684 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid,
5686 c->closes |= CLOSES_SENT_EOF;
5690 if (pktin->type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION &&
5691 !(c->closes & CLOSES_RCVD_CLOSE)) {
5693 if (!(c->closes & CLOSES_SENT_EOF)) {
5694 bombout(("Received CHANNEL_CLOSE_CONFIRMATION for channel %d"
5695 " for which we never sent CHANNEL_CLOSE\n", i));
5698 c->closes |= CLOSES_RCVD_CLOSE;
5701 if (!((CLOSES_SENT_EOF | CLOSES_RCVD_EOF) & ~c->closes) &&
5702 !(c->closes & CLOSES_SENT_CLOSE)) {
5703 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION,
5704 PKT_INT, c->remoteid, PKT_END);
5705 c->closes |= CLOSES_SENT_CLOSE;
5708 if (!((CLOSES_SENT_CLOSE | CLOSES_RCVD_CLOSE) & ~c->closes))
5709 ssh_channel_destroy(c);
5711 bombout(("Received CHANNEL_CLOSE%s for %s channel %d\n",
5712 pktin->type == SSH1_MSG_CHANNEL_CLOSE ? "" :
5713 "_CONFIRMATION", c ? "half-open" : "nonexistent",
5718 static void ssh1_msg_channel_data(Ssh ssh, struct Packet *pktin)
5720 /* Data sent down one of our channels. */
5721 int i = ssh_pkt_getuint32(pktin);
5724 struct ssh_channel *c;
5726 ssh_pkt_getstring(pktin, &p, &len);
5728 c = find234(ssh->channels, &i, ssh_channelfind);
5733 bufsize = x11_send(c->u.x11.xconn, p, len);
5736 bufsize = pfd_send(c->u.pfd.pf, p, len);
5739 /* Data for an agent message. Buffer it. */
5741 if (c->u.a.lensofar < 4) {
5742 unsigned int l = min(4 - c->u.a.lensofar, (unsigned)len);
5743 memcpy(c->u.a.msglen + c->u.a.lensofar, p,
5747 c->u.a.lensofar += l;
5749 if (c->u.a.lensofar == 4) {
5751 4 + GET_32BIT(c->u.a.msglen);
5752 c->u.a.message = snewn(c->u.a.totallen,
5754 memcpy(c->u.a.message, c->u.a.msglen, 4);
5756 if (c->u.a.lensofar >= 4 && len > 0) {
5758 min(c->u.a.totallen - c->u.a.lensofar,
5760 memcpy(c->u.a.message + c->u.a.lensofar, p,
5764 c->u.a.lensofar += l;
5766 if (c->u.a.lensofar == c->u.a.totallen) {
5769 c->u.a.outstanding_requests++;
5770 if (agent_query(c->u.a.message,
5773 ssh_agentf_callback, c))
5774 ssh_agentf_callback(c, reply, replylen);
5775 sfree(c->u.a.message);
5776 c->u.a.lensofar = 0;
5779 bufsize = 0; /* agent channels never back up */
5782 if (!c->throttling_conn && bufsize > SSH1_BUFFER_LIMIT) {
5783 c->throttling_conn = 1;
5784 ssh_throttle_conn(ssh, +1);
5789 static void ssh1_smsg_exit_status(Ssh ssh, struct Packet *pktin)
5791 ssh->exitcode = ssh_pkt_getuint32(pktin);
5792 logeventf(ssh, "Server sent command exit status %d", ssh->exitcode);
5793 send_packet(ssh, SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
5795 * In case `helpful' firewalls or proxies tack
5796 * extra human-readable text on the end of the
5797 * session which we might mistake for another
5798 * encrypted packet, we close the session once
5799 * we've sent EXIT_CONFIRMATION.
5801 ssh_disconnect(ssh, NULL, NULL, 0, TRUE);
5804 /* Helper function to deal with sending tty modes for REQUEST_PTY */
5805 static void ssh1_send_ttymode(void *data, char *mode, char *val)
5807 struct Packet *pktout = (struct Packet *)data;
5809 unsigned int arg = 0;
5810 while (strcmp(mode, ssh_ttymodes[i].mode) != 0) i++;
5811 if (i == lenof(ssh_ttymodes)) return;
5812 switch (ssh_ttymodes[i].type) {
5814 arg = ssh_tty_parse_specchar(val);
5817 arg = ssh_tty_parse_boolean(val);
5820 ssh2_pkt_addbyte(pktout, ssh_ttymodes[i].opcode);
5821 ssh2_pkt_addbyte(pktout, arg);
5824 int ssh_agent_forwarding_permitted(Ssh ssh)
5826 return conf_get_int(ssh->conf, CONF_agentfwd) && agent_exists();
5829 static void do_ssh1_connection(Ssh ssh, const unsigned char *in, int inlen,
5830 struct Packet *pktin)
5832 crBegin(ssh->do_ssh1_connection_crstate);
5834 ssh->packet_dispatch[SSH1_SMSG_STDOUT_DATA] =
5835 ssh->packet_dispatch[SSH1_SMSG_STDERR_DATA] =
5836 ssh1_smsg_stdout_stderr_data;
5838 ssh->packet_dispatch[SSH1_MSG_CHANNEL_OPEN_CONFIRMATION] =
5839 ssh1_msg_channel_open_confirmation;
5840 ssh->packet_dispatch[SSH1_MSG_CHANNEL_OPEN_FAILURE] =
5841 ssh1_msg_channel_open_failure;
5842 ssh->packet_dispatch[SSH1_MSG_CHANNEL_CLOSE] =
5843 ssh->packet_dispatch[SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION] =
5844 ssh1_msg_channel_close;
5845 ssh->packet_dispatch[SSH1_MSG_CHANNEL_DATA] = ssh1_msg_channel_data;
5846 ssh->packet_dispatch[SSH1_SMSG_EXIT_STATUS] = ssh1_smsg_exit_status;
5848 if (ssh_agent_forwarding_permitted(ssh)) {
5849 logevent("Requesting agent forwarding");
5850 send_packet(ssh, SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END);
5854 if (pktin->type != SSH1_SMSG_SUCCESS
5855 && pktin->type != SSH1_SMSG_FAILURE) {
5856 bombout(("Protocol confusion"));
5858 } else if (pktin->type == SSH1_SMSG_FAILURE) {
5859 logevent("Agent forwarding refused");
5861 logevent("Agent forwarding enabled");
5862 ssh->agentfwd_enabled = TRUE;
5863 ssh->packet_dispatch[SSH1_SMSG_AGENT_OPEN] = ssh1_smsg_agent_open;
5867 if (conf_get_int(ssh->conf, CONF_x11_forward)) {
5869 x11_setup_display(conf_get_str(ssh->conf, CONF_x11_display),
5871 if (!ssh->x11disp) {
5872 /* FIXME: return an error message from x11_setup_display */
5873 logevent("X11 forwarding not enabled: unable to"
5874 " initialise X display");
5876 ssh->x11auth = x11_invent_fake_auth
5877 (ssh->x11authtree, conf_get_int(ssh->conf, CONF_x11_auth));
5878 ssh->x11auth->disp = ssh->x11disp;
5880 logevent("Requesting X11 forwarding");
5881 if (ssh->v1_local_protoflags & SSH1_PROTOFLAG_SCREEN_NUMBER) {
5882 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
5883 PKT_STR, ssh->x11auth->protoname,
5884 PKT_STR, ssh->x11auth->datastring,
5885 PKT_INT, ssh->x11disp->screennum,
5888 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
5889 PKT_STR, ssh->x11auth->protoname,
5890 PKT_STR, ssh->x11auth->datastring,
5896 if (pktin->type != SSH1_SMSG_SUCCESS
5897 && pktin->type != SSH1_SMSG_FAILURE) {
5898 bombout(("Protocol confusion"));
5900 } else if (pktin->type == SSH1_SMSG_FAILURE) {
5901 logevent("X11 forwarding refused");
5903 logevent("X11 forwarding enabled");
5904 ssh->X11_fwd_enabled = TRUE;
5905 ssh->packet_dispatch[SSH1_SMSG_X11_OPEN] = ssh1_smsg_x11_open;
5910 ssh_setup_portfwd(ssh, ssh->conf);
5911 ssh->packet_dispatch[SSH1_MSG_PORT_OPEN] = ssh1_msg_port_open;
5913 if (!conf_get_int(ssh->conf, CONF_nopty)) {
5915 /* Unpick the terminal-speed string. */
5916 /* XXX perhaps we should allow no speeds to be sent. */
5917 ssh->ospeed = 38400; ssh->ispeed = 38400; /* last-resort defaults */
5918 sscanf(conf_get_str(ssh->conf, CONF_termspeed), "%d,%d", &ssh->ospeed, &ssh->ispeed);
5919 /* Send the pty request. */
5920 pkt = ssh1_pkt_init(SSH1_CMSG_REQUEST_PTY);
5921 ssh_pkt_addstring(pkt, conf_get_str(ssh->conf, CONF_termtype));
5922 ssh_pkt_adduint32(pkt, ssh->term_height);
5923 ssh_pkt_adduint32(pkt, ssh->term_width);
5924 ssh_pkt_adduint32(pkt, 0); /* width in pixels */
5925 ssh_pkt_adduint32(pkt, 0); /* height in pixels */
5926 parse_ttymodes(ssh, ssh1_send_ttymode, (void *)pkt);
5927 ssh_pkt_addbyte(pkt, SSH1_TTY_OP_ISPEED);
5928 ssh_pkt_adduint32(pkt, ssh->ispeed);
5929 ssh_pkt_addbyte(pkt, SSH1_TTY_OP_OSPEED);
5930 ssh_pkt_adduint32(pkt, ssh->ospeed);
5931 ssh_pkt_addbyte(pkt, SSH_TTY_OP_END);
5933 ssh->state = SSH_STATE_INTERMED;
5937 if (pktin->type != SSH1_SMSG_SUCCESS
5938 && pktin->type != SSH1_SMSG_FAILURE) {
5939 bombout(("Protocol confusion"));
5941 } else if (pktin->type == SSH1_SMSG_FAILURE) {
5942 c_write_str(ssh, "Server refused to allocate pty\r\n");
5943 ssh->editing = ssh->echoing = 1;
5945 logeventf(ssh, "Allocated pty (ospeed %dbps, ispeed %dbps)",
5946 ssh->ospeed, ssh->ispeed);
5947 ssh->got_pty = TRUE;
5950 ssh->editing = ssh->echoing = 1;
5953 if (conf_get_int(ssh->conf, CONF_compression)) {
5954 send_packet(ssh, SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END);
5958 if (pktin->type != SSH1_SMSG_SUCCESS
5959 && pktin->type != SSH1_SMSG_FAILURE) {
5960 bombout(("Protocol confusion"));
5962 } else if (pktin->type == SSH1_SMSG_FAILURE) {
5963 c_write_str(ssh, "Server refused to compress\r\n");
5965 logevent("Started compression");
5966 ssh->v1_compressing = TRUE;
5967 ssh->cs_comp_ctx = zlib_compress_init();
5968 logevent("Initialised zlib (RFC1950) compression");
5969 ssh->sc_comp_ctx = zlib_decompress_init();
5970 logevent("Initialised zlib (RFC1950) decompression");
5974 * Start the shell or command.
5976 * Special case: if the first-choice command is an SSH-2
5977 * subsystem (hence not usable here) and the second choice
5978 * exists, we fall straight back to that.
5981 char *cmd = conf_get_str(ssh->conf, CONF_remote_cmd);
5983 if (conf_get_int(ssh->conf, CONF_ssh_subsys) &&
5984 conf_get_str(ssh->conf, CONF_remote_cmd2)) {
5985 cmd = conf_get_str(ssh->conf, CONF_remote_cmd2);
5986 ssh->fallback_cmd = TRUE;
5989 send_packet(ssh, SSH1_CMSG_EXEC_CMD, PKT_STR, cmd, PKT_END);
5991 send_packet(ssh, SSH1_CMSG_EXEC_SHELL, PKT_END);
5992 logevent("Started session");
5995 ssh->state = SSH_STATE_SESSION;
5996 if (ssh->size_needed)
5997 ssh_size(ssh, ssh->term_width, ssh->term_height);
5998 if (ssh->eof_needed)
5999 ssh_special(ssh, TS_EOF);
6002 ldisc_echoedit_update(ssh->ldisc); /* cause ldisc to notice changes */
6004 ssh->channels = newtree234(ssh_channelcmp);
6008 * By this point, most incoming packets are already being
6009 * handled by the dispatch table, and we need only pay
6010 * attention to the unusual ones.
6015 if (pktin->type == SSH1_SMSG_SUCCESS) {
6016 /* may be from EXEC_SHELL on some servers */
6017 } else if (pktin->type == SSH1_SMSG_FAILURE) {
6018 /* may be from EXEC_SHELL on some servers
6019 * if no pty is available or in other odd cases. Ignore */
6021 bombout(("Strange packet received: type %d", pktin->type));
6026 int len = min(inlen, 512);
6027 send_packet(ssh, SSH1_CMSG_STDIN_DATA,
6028 PKT_INT, len, PKT_DATA, in, len,
6040 * Handle the top-level SSH-2 protocol.
6042 static void ssh1_msg_debug(Ssh ssh, struct Packet *pktin)
6047 ssh_pkt_getstring(pktin, &msg, &msglen);
6048 logeventf(ssh, "Remote debug message: %.*s", msglen, msg);
6051 static void ssh1_msg_disconnect(Ssh ssh, struct Packet *pktin)
6053 /* log reason code in disconnect message */
6057 ssh_pkt_getstring(pktin, &msg, &msglen);
6058 bombout(("Server sent disconnect message:\n\"%.*s\"", msglen, msg));
6061 static void ssh_msg_ignore(Ssh ssh, struct Packet *pktin)
6063 /* Do nothing, because we're ignoring it! Duhh. */
6066 static void ssh1_protocol_setup(Ssh ssh)
6071 * Most messages are handled by the coroutines.
6073 for (i = 0; i < 256; i++)
6074 ssh->packet_dispatch[i] = NULL;
6077 * These special message types we install handlers for.
6079 ssh->packet_dispatch[SSH1_MSG_DISCONNECT] = ssh1_msg_disconnect;
6080 ssh->packet_dispatch[SSH1_MSG_IGNORE] = ssh_msg_ignore;
6081 ssh->packet_dispatch[SSH1_MSG_DEBUG] = ssh1_msg_debug;
6084 static void ssh1_protocol(Ssh ssh, const void *vin, int inlen,
6085 struct Packet *pktin)
6087 const unsigned char *in = (const unsigned char *)vin;
6088 if (ssh->state == SSH_STATE_CLOSED)
6091 if (pktin && ssh->packet_dispatch[pktin->type]) {
6092 ssh->packet_dispatch[pktin->type](ssh, pktin);
6096 if (!ssh->protocol_initial_phase_done) {
6097 if (do_ssh1_login(ssh, in, inlen, pktin))
6098 ssh->protocol_initial_phase_done = TRUE;
6103 do_ssh1_connection(ssh, in, inlen, pktin);
6107 * Utility routines for decoding comma-separated strings in KEXINIT.
6109 static int first_in_commasep_string(char const *needle, char const *haystack,
6113 if (!needle || !haystack) /* protect against null pointers */
6115 needlen = strlen(needle);
6117 if (haylen >= needlen && /* haystack is long enough */
6118 !memcmp(needle, haystack, needlen) && /* initial match */
6119 (haylen == needlen || haystack[needlen] == ',')
6120 /* either , or EOS follows */
6126 static int in_commasep_string(char const *needle, char const *haystack,
6131 if (!needle || !haystack) /* protect against null pointers */
6134 * Is it at the start of the string?
6136 if (first_in_commasep_string(needle, haystack, haylen))
6139 * If not, search for the next comma and resume after that.
6140 * If no comma found, terminate.
6142 p = memchr(haystack, ',', haylen);
6144 /* + 1 to skip over comma */
6145 return in_commasep_string(needle, p + 1, haylen - (p + 1 - haystack));
6149 * Add a value to the comma-separated string at the end of the packet.
6151 static void ssh2_pkt_addstring_commasep(struct Packet *pkt, const char *data)
6153 if (pkt->length - pkt->savedpos > 0)
6154 ssh_pkt_addstring_str(pkt, ",");
6155 ssh_pkt_addstring_str(pkt, data);
6160 * SSH-2 key derivation (RFC 4253 section 7.2).
6162 static unsigned char *ssh2_mkkey(Ssh ssh, Bignum K, unsigned char *H,
6163 char chr, int keylen)
6165 const struct ssh_hash *h = ssh->kex->hash;
6173 /* Round up to the next multiple of hash length. */
6174 keylen_padded = ((keylen + h->hlen - 1) / h->hlen) * h->hlen;
6176 key = snewn(keylen_padded, unsigned char);
6178 /* First hlen bytes. */
6180 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
6181 hash_mpint(h, s, K);
6182 h->bytes(s, H, h->hlen);
6183 h->bytes(s, &chr, 1);
6184 h->bytes(s, ssh->v2_session_id, ssh->v2_session_id_len);
6187 /* Subsequent blocks of hlen bytes. */
6188 if (keylen_padded > h->hlen) {
6192 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
6193 hash_mpint(h, s, K);
6194 h->bytes(s, H, h->hlen);
6196 for (offset = h->hlen; offset < keylen_padded; offset += h->hlen) {
6197 h->bytes(s, key + offset - h->hlen, h->hlen);
6199 h->final(s2, key + offset);
6205 /* Now clear any extra bytes of key material beyond the length
6206 * we're officially returning, because the caller won't know to
6208 if (keylen_padded > keylen)
6209 smemclr(key + keylen, keylen_padded - keylen);
6215 * Structure for constructing KEXINIT algorithm lists.
6217 #define MAXKEXLIST 16
6218 struct kexinit_algorithm {
6222 const struct ssh_kex *kex;
6225 const struct ssh_signkey *hostkey;
6227 const struct ssh2_cipher *cipher;
6231 const struct ssh_mac *mac;
6234 const struct ssh_compress *comp;
6239 * Find a slot in a KEXINIT algorithm list to use for a new algorithm.
6240 * If the algorithm is already in the list, return a pointer to its
6241 * entry, otherwise return an entry from the end of the list.
6242 * This assumes that every time a particular name is passed in, it
6243 * comes from the same string constant. If this isn't true, this
6244 * function may need to be rewritten to use strcmp() instead.
6246 static struct kexinit_algorithm *ssh2_kexinit_addalg(struct kexinit_algorithm
6247 *list, const char *name)
6251 for (i = 0; i < MAXKEXLIST; i++)
6252 if (list[i].name == NULL || list[i].name == name) {
6253 list[i].name = name;
6256 assert(!"No space in KEXINIT list");
6261 * Handle the SSH-2 transport layer.
6263 static void do_ssh2_transport(Ssh ssh, const void *vin, int inlen,
6264 struct Packet *pktin)
6266 const unsigned char *in = (const unsigned char *)vin;
6268 KEXLIST_KEX, KEXLIST_HOSTKEY, KEXLIST_CSCIPHER, KEXLIST_SCCIPHER,
6269 KEXLIST_CSMAC, KEXLIST_SCMAC, KEXLIST_CSCOMP, KEXLIST_SCCOMP,
6272 const char * kexlist_descr[NKEXLIST] = {
6273 "key exchange algorithm", "host key algorithm",
6274 "client-to-server cipher", "server-to-client cipher",
6275 "client-to-server MAC", "server-to-client MAC",
6276 "client-to-server compression method",
6277 "server-to-client compression method" };
6278 struct do_ssh2_transport_state {
6280 int nbits, pbits, warn_kex, warn_cscipher, warn_sccipher;
6281 Bignum p, g, e, f, K;
6284 int kex_init_value, kex_reply_value;
6285 const struct ssh_mac **maclist;
6287 const struct ssh2_cipher *cscipher_tobe;
6288 const struct ssh2_cipher *sccipher_tobe;
6289 const struct ssh_mac *csmac_tobe;
6290 const struct ssh_mac *scmac_tobe;
6291 int csmac_etm_tobe, scmac_etm_tobe;
6292 const struct ssh_compress *cscomp_tobe;
6293 const struct ssh_compress *sccomp_tobe;
6294 char *hostkeydata, *sigdata, *rsakeydata, *keystr, *fingerprint;
6295 int hostkeylen, siglen, rsakeylen;
6296 void *hkey; /* actual host key */
6297 void *rsakey; /* for RSA kex */
6298 void *eckey; /* for ECDH kex */
6299 unsigned char exchange_hash[SSH2_KEX_MAX_HASH_LEN];
6300 int n_preferred_kex;
6301 const struct ssh_kexes *preferred_kex[KEX_MAX];
6302 int n_preferred_ciphers;
6303 const struct ssh2_ciphers *preferred_ciphers[CIPHER_MAX];
6304 const struct ssh_compress *preferred_comp;
6305 int userauth_succeeded; /* for delayed compression */
6306 int pending_compression;
6307 int got_session_id, activated_authconn;
6308 struct Packet *pktout;
6312 struct kexinit_algorithm kexlists[NKEXLIST][MAXKEXLIST];
6314 crState(do_ssh2_transport_state);
6316 assert(!ssh->bare_connection);
6320 s->cscipher_tobe = s->sccipher_tobe = NULL;
6321 s->csmac_tobe = s->scmac_tobe = NULL;
6322 s->cscomp_tobe = s->sccomp_tobe = NULL;
6324 s->got_session_id = s->activated_authconn = FALSE;
6325 s->userauth_succeeded = FALSE;
6326 s->pending_compression = FALSE;
6329 * Be prepared to work around the buggy MAC problem.
6331 if (ssh->remote_bugs & BUG_SSH2_HMAC)
6332 s->maclist = buggymacs, s->nmacs = lenof(buggymacs);
6334 s->maclist = macs, s->nmacs = lenof(macs);
6337 ssh->pkt_kctx = SSH2_PKTCTX_NOKEX;
6340 struct kexinit_algorithm *alg;
6343 * Set up the preferred key exchange. (NULL => warn below here)
6345 s->n_preferred_kex = 0;
6346 for (i = 0; i < KEX_MAX; i++) {
6347 switch (conf_get_int_int(ssh->conf, CONF_ssh_kexlist, i)) {
6349 s->preferred_kex[s->n_preferred_kex++] =
6350 &ssh_diffiehellman_gex;
6353 s->preferred_kex[s->n_preferred_kex++] =
6354 &ssh_diffiehellman_group14;
6357 s->preferred_kex[s->n_preferred_kex++] =
6358 &ssh_diffiehellman_group1;
6361 s->preferred_kex[s->n_preferred_kex++] =
6365 s->preferred_kex[s->n_preferred_kex++] =
6369 /* Flag for later. Don't bother if it's the last in
6371 if (i < KEX_MAX - 1) {
6372 s->preferred_kex[s->n_preferred_kex++] = NULL;
6379 * Set up the preferred ciphers. (NULL => warn below here)
6381 s->n_preferred_ciphers = 0;
6382 for (i = 0; i < CIPHER_MAX; i++) {
6383 switch (conf_get_int_int(ssh->conf, CONF_ssh_cipherlist, i)) {
6384 case CIPHER_BLOWFISH:
6385 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_blowfish;
6388 if (conf_get_int(ssh->conf, CONF_ssh2_des_cbc)) {
6389 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_des;
6393 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_3des;
6396 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_aes;
6398 case CIPHER_ARCFOUR:
6399 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_arcfour;
6401 case CIPHER_CHACHA20:
6402 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_ccp;
6405 /* Flag for later. Don't bother if it's the last in
6407 if (i < CIPHER_MAX - 1) {
6408 s->preferred_ciphers[s->n_preferred_ciphers++] = NULL;
6415 * Set up preferred compression.
6417 if (conf_get_int(ssh->conf, CONF_compression))
6418 s->preferred_comp = &ssh_zlib;
6420 s->preferred_comp = &ssh_comp_none;
6423 * Enable queueing of outgoing auth- or connection-layer
6424 * packets while we are in the middle of a key exchange.
6426 ssh->queueing = TRUE;
6429 * Flag that KEX is in progress.
6431 ssh->kex_in_progress = TRUE;
6433 for (i = 0; i < NKEXLIST; i++)
6434 for (j = 0; j < MAXKEXLIST; j++)
6435 s->kexlists[i][j].name = NULL;
6436 /* List key exchange algorithms. */
6438 for (i = 0; i < s->n_preferred_kex; i++) {
6439 const struct ssh_kexes *k = s->preferred_kex[i];
6440 if (!k) warn = TRUE;
6441 else for (j = 0; j < k->nkexes; j++) {
6442 alg = ssh2_kexinit_addalg(s->kexlists[KEXLIST_KEX],
6444 alg->u.kex.kex = k->list[j];
6445 alg->u.kex.warn = warn;
6448 /* List server host key algorithms. */
6449 if (!s->got_session_id) {
6451 * In the first key exchange, we list all the algorithms
6452 * we're prepared to cope with, but prefer those algorithms
6453 * for which we have a host key for this host.
6455 for (i = 0; i < lenof(hostkey_algs); i++) {
6456 if (have_ssh_host_key(ssh->savedhost, ssh->savedport,
6457 hostkey_algs[i]->keytype)) {
6458 alg = ssh2_kexinit_addalg(s->kexlists[KEXLIST_HOSTKEY],
6459 hostkey_algs[i]->name);
6460 alg->u.hostkey = hostkey_algs[i];
6463 for (i = 0; i < lenof(hostkey_algs); i++) {
6464 alg = ssh2_kexinit_addalg(s->kexlists[KEXLIST_HOSTKEY],
6465 hostkey_algs[i]->name);
6466 alg->u.hostkey = hostkey_algs[i];
6470 * In subsequent key exchanges, we list only the kex
6471 * algorithm that was selected in the first key exchange,
6472 * so that we keep getting the same host key and hence
6473 * don't have to interrupt the user's session to ask for
6477 alg = ssh2_kexinit_addalg(s->kexlists[KEXLIST_HOSTKEY],
6478 ssh->hostkey->name);
6479 alg->u.hostkey = ssh->hostkey;
6481 /* List encryption algorithms (client->server then server->client). */
6482 for (k = KEXLIST_CSCIPHER; k <= KEXLIST_SCCIPHER; k++) {
6485 alg = ssh2_kexinit_addalg(s->kexlists[k], "none");
6486 alg->u.cipher.cipher = NULL;
6487 alg->u.cipher.warn = warn;
6488 #endif /* FUZZING */
6489 for (i = 0; i < s->n_preferred_ciphers; i++) {
6490 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
6491 if (!c) warn = TRUE;
6492 else for (j = 0; j < c->nciphers; j++) {
6493 alg = ssh2_kexinit_addalg(s->kexlists[k],
6495 alg->u.cipher.cipher = c->list[j];
6496 alg->u.cipher.warn = warn;
6500 /* List MAC algorithms (client->server then server->client). */
6501 for (j = KEXLIST_CSMAC; j <= KEXLIST_SCMAC; j++) {
6503 alg = ssh2_kexinit_addalg(s->kexlists[j], "none");
6504 alg->u.mac.mac = NULL;
6505 alg->u.mac.etm = FALSE;
6506 #endif /* FUZZING */
6507 for (i = 0; i < s->nmacs; i++) {
6508 alg = ssh2_kexinit_addalg(s->kexlists[j], s->maclist[i]->name);
6509 alg->u.mac.mac = s->maclist[i];
6510 alg->u.mac.etm = FALSE;
6512 for (i = 0; i < s->nmacs; i++)
6513 /* For each MAC, there may also be an ETM version,
6514 * which we list second. */
6515 if (s->maclist[i]->etm_name) {
6516 alg = ssh2_kexinit_addalg(s->kexlists[j],
6517 s->maclist[i]->etm_name);
6518 alg->u.mac.mac = s->maclist[i];
6519 alg->u.mac.etm = TRUE;
6522 /* List client->server compression algorithms,
6523 * then server->client compression algorithms. (We use the
6524 * same set twice.) */
6525 for (j = KEXLIST_CSCOMP; j <= KEXLIST_SCCOMP; j++) {
6526 assert(lenof(compressions) > 1);
6527 /* Prefer non-delayed versions */
6528 alg = ssh2_kexinit_addalg(s->kexlists[j], s->preferred_comp->name);
6529 alg->u.comp = s->preferred_comp;
6530 /* We don't even list delayed versions of algorithms until
6531 * they're allowed to be used, to avoid a race. See the end of
6533 if (s->userauth_succeeded && s->preferred_comp->delayed_name) {
6534 alg = ssh2_kexinit_addalg(s->kexlists[j],
6535 s->preferred_comp->delayed_name);
6536 alg->u.comp = s->preferred_comp;
6538 for (i = 0; i < lenof(compressions); i++) {
6539 const struct ssh_compress *c = compressions[i];
6540 alg = ssh2_kexinit_addalg(s->kexlists[j], c->name);
6542 if (s->userauth_succeeded && c->delayed_name) {
6543 alg = ssh2_kexinit_addalg(s->kexlists[j], c->delayed_name);
6549 * Construct and send our key exchange packet.
6551 s->pktout = ssh2_pkt_init(SSH2_MSG_KEXINIT);
6552 for (i = 0; i < 16; i++)
6553 ssh2_pkt_addbyte(s->pktout, (unsigned char) random_byte());
6554 for (i = 0; i < NKEXLIST; i++) {
6555 ssh2_pkt_addstring_start(s->pktout);
6556 for (j = 0; j < MAXKEXLIST; j++) {
6557 if (s->kexlists[i][j].name == NULL) break;
6558 ssh2_pkt_addstring_commasep(s->pktout, s->kexlists[i][j].name);
6561 /* List client->server languages. Empty list. */
6562 ssh2_pkt_addstring_start(s->pktout);
6563 /* List server->client languages. Empty list. */
6564 ssh2_pkt_addstring_start(s->pktout);
6565 /* First KEX packet does _not_ follow, because we're not that brave. */
6566 ssh2_pkt_addbool(s->pktout, FALSE);
6568 ssh2_pkt_adduint32(s->pktout, 0);
6571 s->our_kexinitlen = s->pktout->length - 5;
6572 s->our_kexinit = snewn(s->our_kexinitlen, unsigned char);
6573 memcpy(s->our_kexinit, s->pktout->data + 5, s->our_kexinitlen);
6575 ssh2_pkt_send_noqueue(ssh, s->pktout);
6578 crWaitUntilV(pktin);
6581 * Now examine the other side's KEXINIT to see what we're up
6588 if (pktin->type != SSH2_MSG_KEXINIT) {
6589 bombout(("expected key exchange packet from server"));
6593 ssh->hostkey = NULL;
6594 s->cscipher_tobe = NULL;
6595 s->sccipher_tobe = NULL;
6596 s->csmac_tobe = NULL;
6597 s->scmac_tobe = NULL;
6598 s->cscomp_tobe = NULL;
6599 s->sccomp_tobe = NULL;
6600 s->warn_kex = s->warn_cscipher = s->warn_sccipher = FALSE;
6602 pktin->savedpos += 16; /* skip garbage cookie */
6605 for (i = 0; i < NKEXLIST; i++) {
6606 ssh_pkt_getstring(pktin, &str, &len);
6608 bombout(("KEXINIT packet was incomplete"));
6612 /* If we've already selected a cipher which requires a
6613 * particular MAC, then just select that, and don't even
6614 * bother looking through the server's KEXINIT string for
6616 if (i == KEXLIST_CSMAC && s->cscipher_tobe &&
6617 s->cscipher_tobe->required_mac) {
6618 s->csmac_tobe = s->cscipher_tobe->required_mac;
6619 s->csmac_etm_tobe = !!(s->csmac_tobe->etm_name);
6622 if (i == KEXLIST_SCMAC && s->sccipher_tobe &&
6623 s->sccipher_tobe->required_mac) {
6624 s->scmac_tobe = s->sccipher_tobe->required_mac;
6625 s->scmac_etm_tobe = !!(s->scmac_tobe->etm_name);
6629 for (j = 0; j < MAXKEXLIST; j++) {
6630 struct kexinit_algorithm *alg = &s->kexlists[i][j];
6631 if (alg->name == NULL) break;
6632 if (in_commasep_string(alg->name, str, len)) {
6633 /* We've found a matching algorithm. */
6634 if (i == KEXLIST_KEX || i == KEXLIST_HOSTKEY) {
6635 /* Check if we might need to ignore first kex pkt */
6637 !first_in_commasep_string(alg->name, str, len))
6640 if (i == KEXLIST_KEX) {
6641 ssh->kex = alg->u.kex.kex;
6642 s->warn_kex = alg->u.kex.warn;
6643 } else if (i == KEXLIST_HOSTKEY) {
6644 ssh->hostkey = alg->u.hostkey;
6645 } else if (i == KEXLIST_CSCIPHER) {
6646 s->cscipher_tobe = alg->u.cipher.cipher;
6647 s->warn_cscipher = alg->u.cipher.warn;
6648 } else if (i == KEXLIST_SCCIPHER) {
6649 s->sccipher_tobe = alg->u.cipher.cipher;
6650 s->warn_sccipher = alg->u.cipher.warn;
6651 } else if (i == KEXLIST_CSMAC) {
6652 s->csmac_tobe = alg->u.mac.mac;
6653 s->csmac_etm_tobe = alg->u.mac.etm;
6654 } else if (i == KEXLIST_SCMAC) {
6655 s->scmac_tobe = alg->u.mac.mac;
6656 s->scmac_etm_tobe = alg->u.mac.etm;
6657 } else if (i == KEXLIST_CSCOMP) {
6658 s->cscomp_tobe = alg->u.comp;
6659 } else if (i == KEXLIST_SCCOMP) {
6660 s->sccomp_tobe = alg->u.comp;
6664 if ((i == KEXLIST_CSCOMP || i == KEXLIST_SCCOMP) &&
6665 in_commasep_string(alg->u.comp->delayed_name, str, len))
6666 s->pending_compression = TRUE; /* try this later */
6668 bombout(("Couldn't agree a %s ((available: %.*s)",
6669 kexlist_descr[i], len, str));
6674 if (s->pending_compression) {
6675 logevent("Server supports delayed compression; "
6676 "will try this later");
6678 ssh_pkt_getstring(pktin, &str, &len); /* client->server language */
6679 ssh_pkt_getstring(pktin, &str, &len); /* server->client language */
6680 s->ignorepkt = ssh2_pkt_getbool(pktin) && !s->guessok;
6682 ssh->exhash = ssh->kex->hash->init();
6683 hash_string(ssh->kex->hash, ssh->exhash, ssh->v_c, strlen(ssh->v_c));
6684 hash_string(ssh->kex->hash, ssh->exhash, ssh->v_s, strlen(ssh->v_s));
6685 hash_string(ssh->kex->hash, ssh->exhash,
6686 s->our_kexinit, s->our_kexinitlen);
6687 sfree(s->our_kexinit);
6688 /* Include the type byte in the hash of server's KEXINIT */
6689 hash_string(ssh->kex->hash, ssh->exhash,
6690 pktin->body - 1, pktin->length + 1);
6693 ssh_set_frozen(ssh, 1);
6694 s->dlgret = askalg(ssh->frontend, "key-exchange algorithm",
6696 ssh_dialog_callback, ssh);
6697 if (s->dlgret < 0) {
6701 bombout(("Unexpected data from server while"
6702 " waiting for user response"));
6705 } while (pktin || inlen > 0);
6706 s->dlgret = ssh->user_response;
6708 ssh_set_frozen(ssh, 0);
6709 if (s->dlgret == 0) {
6710 ssh_disconnect(ssh, "User aborted at kex warning", NULL,
6716 if (s->warn_cscipher) {
6717 ssh_set_frozen(ssh, 1);
6718 s->dlgret = askalg(ssh->frontend,
6719 "client-to-server cipher",
6720 s->cscipher_tobe->name,
6721 ssh_dialog_callback, ssh);
6722 if (s->dlgret < 0) {
6726 bombout(("Unexpected data from server while"
6727 " waiting for user response"));
6730 } while (pktin || inlen > 0);
6731 s->dlgret = ssh->user_response;
6733 ssh_set_frozen(ssh, 0);
6734 if (s->dlgret == 0) {
6735 ssh_disconnect(ssh, "User aborted at cipher warning", NULL,
6741 if (s->warn_sccipher) {
6742 ssh_set_frozen(ssh, 1);
6743 s->dlgret = askalg(ssh->frontend,
6744 "server-to-client cipher",
6745 s->sccipher_tobe->name,
6746 ssh_dialog_callback, ssh);
6747 if (s->dlgret < 0) {
6751 bombout(("Unexpected data from server while"
6752 " waiting for user response"));
6755 } while (pktin || inlen > 0);
6756 s->dlgret = ssh->user_response;
6758 ssh_set_frozen(ssh, 0);
6759 if (s->dlgret == 0) {
6760 ssh_disconnect(ssh, "User aborted at cipher warning", NULL,
6766 if (s->ignorepkt) /* first_kex_packet_follows */
6767 crWaitUntilV(pktin); /* Ignore packet */
6770 if (ssh->kex->main_type == KEXTYPE_DH) {
6772 * Work out the number of bits of key we will need from the
6773 * key exchange. We start with the maximum key length of
6779 csbits = s->cscipher_tobe ? s->cscipher_tobe->real_keybits : 0;
6780 scbits = s->sccipher_tobe ? s->sccipher_tobe->real_keybits : 0;
6781 s->nbits = (csbits > scbits ? csbits : scbits);
6783 /* The keys only have hlen-bit entropy, since they're based on
6784 * a hash. So cap the key size at hlen bits. */
6785 if (s->nbits > ssh->kex->hash->hlen * 8)
6786 s->nbits = ssh->kex->hash->hlen * 8;
6789 * If we're doing Diffie-Hellman group exchange, start by
6790 * requesting a group.
6792 if (dh_is_gex(ssh->kex)) {
6793 logevent("Doing Diffie-Hellman group exchange");
6794 ssh->pkt_kctx = SSH2_PKTCTX_DHGEX;
6796 * Work out how big a DH group we will need to allow that
6799 s->pbits = 512 << ((s->nbits - 1) / 64);
6800 if (s->pbits < DH_MIN_SIZE)
6801 s->pbits = DH_MIN_SIZE;
6802 if (s->pbits > DH_MAX_SIZE)
6803 s->pbits = DH_MAX_SIZE;
6804 if ((ssh->remote_bugs & BUG_SSH2_OLDGEX)) {
6805 s->pktout = ssh2_pkt_init(SSH2_MSG_KEX_DH_GEX_REQUEST_OLD);
6806 ssh2_pkt_adduint32(s->pktout, s->pbits);
6808 s->pktout = ssh2_pkt_init(SSH2_MSG_KEX_DH_GEX_REQUEST);
6809 ssh2_pkt_adduint32(s->pktout, DH_MIN_SIZE);
6810 ssh2_pkt_adduint32(s->pktout, s->pbits);
6811 ssh2_pkt_adduint32(s->pktout, DH_MAX_SIZE);
6813 ssh2_pkt_send_noqueue(ssh, s->pktout);
6815 crWaitUntilV(pktin);
6816 if (pktin->type != SSH2_MSG_KEX_DH_GEX_GROUP) {
6817 bombout(("expected key exchange group packet from server"));
6820 s->p = ssh2_pkt_getmp(pktin);
6821 s->g = ssh2_pkt_getmp(pktin);
6822 if (!s->p || !s->g) {
6823 bombout(("unable to read mp-ints from incoming group packet"));
6826 ssh->kex_ctx = dh_setup_gex(s->p, s->g);
6827 s->kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT;
6828 s->kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY;
6830 ssh->pkt_kctx = SSH2_PKTCTX_DHGROUP;
6831 ssh->kex_ctx = dh_setup_group(ssh->kex);
6832 s->kex_init_value = SSH2_MSG_KEXDH_INIT;
6833 s->kex_reply_value = SSH2_MSG_KEXDH_REPLY;
6834 logeventf(ssh, "Using Diffie-Hellman with standard group \"%s\"",
6835 ssh->kex->groupname);
6838 logeventf(ssh, "Doing Diffie-Hellman key exchange with hash %s",
6839 ssh->kex->hash->text_name);
6841 * Now generate and send e for Diffie-Hellman.
6843 set_busy_status(ssh->frontend, BUSY_CPU); /* this can take a while */
6844 s->e = dh_create_e(ssh->kex_ctx, s->nbits * 2);
6845 s->pktout = ssh2_pkt_init(s->kex_init_value);
6846 ssh2_pkt_addmp(s->pktout, s->e);
6847 ssh2_pkt_send_noqueue(ssh, s->pktout);
6849 set_busy_status(ssh->frontend, BUSY_WAITING); /* wait for server */
6850 crWaitUntilV(pktin);
6851 if (pktin->type != s->kex_reply_value) {
6852 bombout(("expected key exchange reply packet from server"));
6855 set_busy_status(ssh->frontend, BUSY_CPU); /* cogitate */
6856 ssh_pkt_getstring(pktin, &s->hostkeydata, &s->hostkeylen);
6857 if (!s->hostkeydata) {
6858 bombout(("unable to parse key exchange reply packet"));
6861 s->hkey = ssh->hostkey->newkey(ssh->hostkey,
6862 s->hostkeydata, s->hostkeylen);
6863 s->f = ssh2_pkt_getmp(pktin);
6865 bombout(("unable to parse key exchange reply packet"));
6868 ssh_pkt_getstring(pktin, &s->sigdata, &s->siglen);
6870 bombout(("unable to parse key exchange reply packet"));
6875 const char *err = dh_validate_f(ssh->kex_ctx, s->f);
6877 bombout(("key exchange reply failed validation: %s", err));
6881 s->K = dh_find_K(ssh->kex_ctx, s->f);
6883 /* We assume everything from now on will be quick, and it might
6884 * involve user interaction. */
6885 set_busy_status(ssh->frontend, BUSY_NOT);
6887 hash_string(ssh->kex->hash, ssh->exhash, s->hostkeydata, s->hostkeylen);
6888 if (dh_is_gex(ssh->kex)) {
6889 if (!(ssh->remote_bugs & BUG_SSH2_OLDGEX))
6890 hash_uint32(ssh->kex->hash, ssh->exhash, DH_MIN_SIZE);
6891 hash_uint32(ssh->kex->hash, ssh->exhash, s->pbits);
6892 if (!(ssh->remote_bugs & BUG_SSH2_OLDGEX))
6893 hash_uint32(ssh->kex->hash, ssh->exhash, DH_MAX_SIZE);
6894 hash_mpint(ssh->kex->hash, ssh->exhash, s->p);
6895 hash_mpint(ssh->kex->hash, ssh->exhash, s->g);
6897 hash_mpint(ssh->kex->hash, ssh->exhash, s->e);
6898 hash_mpint(ssh->kex->hash, ssh->exhash, s->f);
6900 dh_cleanup(ssh->kex_ctx);
6902 if (dh_is_gex(ssh->kex)) {
6906 } else if (ssh->kex->main_type == KEXTYPE_ECDH) {
6908 logeventf(ssh, "Doing ECDH key exchange with curve %s and hash %s",
6909 ssh_ecdhkex_curve_textname(ssh->kex),
6910 ssh->kex->hash->text_name);
6911 ssh->pkt_kctx = SSH2_PKTCTX_ECDHKEX;
6913 s->eckey = ssh_ecdhkex_newkey(ssh->kex);
6915 bombout(("Unable to generate key for ECDH"));
6921 int publicPointLength;
6922 publicPoint = ssh_ecdhkex_getpublic(s->eckey, &publicPointLength);
6924 ssh_ecdhkex_freekey(s->eckey);
6925 bombout(("Unable to encode public key for ECDH"));
6928 s->pktout = ssh2_pkt_init(SSH2_MSG_KEX_ECDH_INIT);
6929 ssh2_pkt_addstring_start(s->pktout);
6930 ssh2_pkt_addstring_data(s->pktout, publicPoint, publicPointLength);
6934 ssh2_pkt_send_noqueue(ssh, s->pktout);
6936 crWaitUntilV(pktin);
6937 if (pktin->type != SSH2_MSG_KEX_ECDH_REPLY) {
6938 ssh_ecdhkex_freekey(s->eckey);
6939 bombout(("expected ECDH reply packet from server"));
6943 ssh_pkt_getstring(pktin, &s->hostkeydata, &s->hostkeylen);
6944 if (!s->hostkeydata) {
6945 bombout(("unable to parse ECDH reply packet"));
6948 hash_string(ssh->kex->hash, ssh->exhash, s->hostkeydata, s->hostkeylen);
6949 s->hkey = ssh->hostkey->newkey(ssh->hostkey,
6950 s->hostkeydata, s->hostkeylen);
6954 int publicPointLength;
6955 publicPoint = ssh_ecdhkex_getpublic(s->eckey, &publicPointLength);
6957 ssh_ecdhkex_freekey(s->eckey);
6958 bombout(("Unable to encode public key for ECDH hash"));
6961 hash_string(ssh->kex->hash, ssh->exhash,
6962 publicPoint, publicPointLength);
6969 ssh_pkt_getstring(pktin, &keydata, &keylen);
6971 bombout(("unable to parse ECDH reply packet"));
6974 hash_string(ssh->kex->hash, ssh->exhash, keydata, keylen);
6975 s->K = ssh_ecdhkex_getkey(s->eckey, keydata, keylen);
6977 ssh_ecdhkex_freekey(s->eckey);
6978 bombout(("point received in ECDH was not valid"));
6983 ssh_pkt_getstring(pktin, &s->sigdata, &s->siglen);
6985 bombout(("unable to parse key exchange reply packet"));
6989 ssh_ecdhkex_freekey(s->eckey);
6991 logeventf(ssh, "Doing RSA key exchange with hash %s",
6992 ssh->kex->hash->text_name);
6993 ssh->pkt_kctx = SSH2_PKTCTX_RSAKEX;
6995 * RSA key exchange. First expect a KEXRSA_PUBKEY packet
6998 crWaitUntilV(pktin);
6999 if (pktin->type != SSH2_MSG_KEXRSA_PUBKEY) {
7000 bombout(("expected RSA public key packet from server"));
7004 ssh_pkt_getstring(pktin, &s->hostkeydata, &s->hostkeylen);
7005 if (!s->hostkeydata) {
7006 bombout(("unable to parse RSA public key packet"));
7009 hash_string(ssh->kex->hash, ssh->exhash,
7010 s->hostkeydata, s->hostkeylen);
7011 s->hkey = ssh->hostkey->newkey(ssh->hostkey,
7012 s->hostkeydata, s->hostkeylen);
7016 ssh_pkt_getstring(pktin, &keydata, &s->rsakeylen);
7018 bombout(("unable to parse RSA public key packet"));
7021 s->rsakeydata = snewn(s->rsakeylen, char);
7022 memcpy(s->rsakeydata, keydata, s->rsakeylen);
7025 s->rsakey = ssh_rsakex_newkey(s->rsakeydata, s->rsakeylen);
7027 sfree(s->rsakeydata);
7028 bombout(("unable to parse RSA public key from server"));
7032 hash_string(ssh->kex->hash, ssh->exhash, s->rsakeydata, s->rsakeylen);
7035 * Next, set up a shared secret K, of precisely KLEN -
7036 * 2*HLEN - 49 bits, where KLEN is the bit length of the
7037 * RSA key modulus and HLEN is the bit length of the hash
7041 int klen = ssh_rsakex_klen(s->rsakey);
7042 int nbits = klen - (2*ssh->kex->hash->hlen*8 + 49);
7044 unsigned char *kstr1, *kstr2, *outstr;
7045 int kstr1len, kstr2len, outstrlen;
7047 s->K = bn_power_2(nbits - 1);
7049 for (i = 0; i < nbits; i++) {
7051 byte = random_byte();
7053 bignum_set_bit(s->K, i, (byte >> (i & 7)) & 1);
7057 * Encode this as an mpint.
7059 kstr1 = ssh2_mpint_fmt(s->K, &kstr1len);
7060 kstr2 = snewn(kstr2len = 4 + kstr1len, unsigned char);
7061 PUT_32BIT(kstr2, kstr1len);
7062 memcpy(kstr2 + 4, kstr1, kstr1len);
7065 * Encrypt it with the given RSA key.
7067 outstrlen = (klen + 7) / 8;
7068 outstr = snewn(outstrlen, unsigned char);
7069 ssh_rsakex_encrypt(ssh->kex->hash, kstr2, kstr2len,
7070 outstr, outstrlen, s->rsakey);
7073 * And send it off in a return packet.
7075 s->pktout = ssh2_pkt_init(SSH2_MSG_KEXRSA_SECRET);
7076 ssh2_pkt_addstring_start(s->pktout);
7077 ssh2_pkt_addstring_data(s->pktout, (char *)outstr, outstrlen);
7078 ssh2_pkt_send_noqueue(ssh, s->pktout);
7080 hash_string(ssh->kex->hash, ssh->exhash, outstr, outstrlen);
7087 ssh_rsakex_freekey(s->rsakey);
7089 crWaitUntilV(pktin);
7090 if (pktin->type != SSH2_MSG_KEXRSA_DONE) {
7091 sfree(s->rsakeydata);
7092 bombout(("expected signature packet from server"));
7096 ssh_pkt_getstring(pktin, &s->sigdata, &s->siglen);
7098 bombout(("unable to parse signature packet"));
7102 sfree(s->rsakeydata);
7105 hash_mpint(ssh->kex->hash, ssh->exhash, s->K);
7106 assert(ssh->kex->hash->hlen <= sizeof(s->exchange_hash));
7107 ssh->kex->hash->final(ssh->exhash, s->exchange_hash);
7109 ssh->kex_ctx = NULL;
7112 debug(("Exchange hash is:\n"));
7113 dmemdump(s->exchange_hash, ssh->kex->hash->hlen);
7117 bombout(("Server's host key is invalid"));
7121 if (!ssh->hostkey->verifysig(s->hkey, s->sigdata, s->siglen,
7122 (char *)s->exchange_hash,
7123 ssh->kex->hash->hlen)) {
7125 bombout(("Server's host key did not match the signature supplied"));
7130 s->keystr = ssh->hostkey->fmtkey(s->hkey);
7131 if (!s->got_session_id) {
7133 * Authenticate remote host: verify host key. (We've already
7134 * checked the signature of the exchange hash.)
7136 s->fingerprint = ssh2_fingerprint(ssh->hostkey, s->hkey);
7137 logevent("Host key fingerprint is:");
7138 logevent(s->fingerprint);
7139 /* First check against manually configured host keys. */
7140 s->dlgret = verify_ssh_manual_host_key(ssh, s->fingerprint,
7141 ssh->hostkey, s->hkey);
7142 if (s->dlgret == 0) { /* did not match */
7143 bombout(("Host key did not appear in manually configured list"));
7145 } else if (s->dlgret < 0) { /* none configured; use standard handling */
7146 ssh_set_frozen(ssh, 1);
7147 s->dlgret = verify_ssh_host_key(ssh->frontend,
7148 ssh->savedhost, ssh->savedport,
7149 ssh->hostkey->keytype, s->keystr,
7151 ssh_dialog_callback, ssh);
7155 if (s->dlgret < 0) {
7159 bombout(("Unexpected data from server while waiting"
7160 " for user host key response"));
7163 } while (pktin || inlen > 0);
7164 s->dlgret = ssh->user_response;
7166 ssh_set_frozen(ssh, 0);
7167 if (s->dlgret == 0) {
7168 ssh_disconnect(ssh, "Aborted at host key verification", NULL,
7173 sfree(s->fingerprint);
7175 * Save this host key, to check against the one presented in
7176 * subsequent rekeys.
7178 ssh->hostkey_str = s->keystr;
7181 * In a rekey, we never present an interactive host key
7182 * verification request to the user. Instead, we simply
7183 * enforce that the key we're seeing this time is identical to
7184 * the one we saw before.
7186 if (strcmp(ssh->hostkey_str, s->keystr)) {
7188 bombout(("Host key was different in repeat key exchange"));
7194 ssh->hostkey->freekey(s->hkey);
7197 * The exchange hash from the very first key exchange is also
7198 * the session id, used in session key construction and
7201 if (!s->got_session_id) {
7202 assert(sizeof(s->exchange_hash) <= sizeof(ssh->v2_session_id));
7203 memcpy(ssh->v2_session_id, s->exchange_hash,
7204 sizeof(s->exchange_hash));
7205 ssh->v2_session_id_len = ssh->kex->hash->hlen;
7206 assert(ssh->v2_session_id_len <= sizeof(ssh->v2_session_id));
7207 s->got_session_id = TRUE;
7211 * Send SSH2_MSG_NEWKEYS.
7213 s->pktout = ssh2_pkt_init(SSH2_MSG_NEWKEYS);
7214 ssh2_pkt_send_noqueue(ssh, s->pktout);
7215 ssh->outgoing_data_size = 0; /* start counting from here */
7218 * We've sent client NEWKEYS, so create and initialise
7219 * client-to-server session keys.
7221 if (ssh->cs_cipher_ctx)
7222 ssh->cscipher->free_context(ssh->cs_cipher_ctx);
7223 ssh->cscipher = s->cscipher_tobe;
7224 if (ssh->cscipher) ssh->cs_cipher_ctx = ssh->cscipher->make_context();
7226 if (ssh->cs_mac_ctx)
7227 ssh->csmac->free_context(ssh->cs_mac_ctx);
7228 ssh->csmac = s->csmac_tobe;
7229 ssh->csmac_etm = s->csmac_etm_tobe;
7231 ssh->cs_mac_ctx = ssh->csmac->make_context(ssh->cs_cipher_ctx);
7233 if (ssh->cs_comp_ctx)
7234 ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
7235 ssh->cscomp = s->cscomp_tobe;
7236 ssh->cs_comp_ctx = ssh->cscomp->compress_init();
7239 * Set IVs on client-to-server keys. Here we use the exchange
7240 * hash from the _first_ key exchange.
7242 if (ssh->cscipher) {
7245 key = ssh2_mkkey(ssh, s->K, s->exchange_hash, 'C',
7246 ssh->cscipher->padded_keybytes);
7247 ssh->cscipher->setkey(ssh->cs_cipher_ctx, key);
7248 smemclr(key, ssh->cscipher->padded_keybytes);
7251 key = ssh2_mkkey(ssh, s->K, s->exchange_hash, 'A',
7252 ssh->cscipher->blksize);
7253 ssh->cscipher->setiv(ssh->cs_cipher_ctx, key);
7254 smemclr(key, ssh->cscipher->blksize);
7260 key = ssh2_mkkey(ssh, s->K, s->exchange_hash, 'E',
7261 ssh->csmac->keylen);
7262 ssh->csmac->setkey(ssh->cs_mac_ctx, key);
7263 smemclr(key, ssh->csmac->keylen);
7268 logeventf(ssh, "Initialised %.200s client->server encryption",
7269 ssh->cscipher->text_name);
7271 logeventf(ssh, "Initialised %.200s client->server MAC algorithm%s%s",
7272 ssh->csmac->text_name,
7273 ssh->csmac_etm ? " (in ETM mode)" : "",
7274 ssh->cscipher->required_mac ? " (required by cipher)" : "");
7275 if (ssh->cscomp->text_name)
7276 logeventf(ssh, "Initialised %s compression",
7277 ssh->cscomp->text_name);
7280 * Now our end of the key exchange is complete, we can send all
7281 * our queued higher-layer packets.
7283 ssh->queueing = FALSE;
7284 ssh2_pkt_queuesend(ssh);
7287 * Expect SSH2_MSG_NEWKEYS from server.
7289 crWaitUntilV(pktin);
7290 if (pktin->type != SSH2_MSG_NEWKEYS) {
7291 bombout(("expected new-keys packet from server"));
7294 ssh->incoming_data_size = 0; /* start counting from here */
7297 * We've seen server NEWKEYS, so create and initialise
7298 * server-to-client session keys.
7300 if (ssh->sc_cipher_ctx)
7301 ssh->sccipher->free_context(ssh->sc_cipher_ctx);
7302 if (s->sccipher_tobe) {
7303 ssh->sccipher = s->sccipher_tobe;
7304 ssh->sc_cipher_ctx = ssh->sccipher->make_context();
7307 if (ssh->sc_mac_ctx)
7308 ssh->scmac->free_context(ssh->sc_mac_ctx);
7309 if (s->scmac_tobe) {
7310 ssh->scmac = s->scmac_tobe;
7311 ssh->scmac_etm = s->scmac_etm_tobe;
7312 ssh->sc_mac_ctx = ssh->scmac->make_context(ssh->sc_cipher_ctx);
7315 if (ssh->sc_comp_ctx)
7316 ssh->sccomp->decompress_cleanup(ssh->sc_comp_ctx);
7317 ssh->sccomp = s->sccomp_tobe;
7318 ssh->sc_comp_ctx = ssh->sccomp->decompress_init();
7321 * Set IVs on server-to-client keys. Here we use the exchange
7322 * hash from the _first_ key exchange.
7324 if (ssh->sccipher) {
7327 key = ssh2_mkkey(ssh, s->K, s->exchange_hash, 'D',
7328 ssh->sccipher->padded_keybytes);
7329 ssh->sccipher->setkey(ssh->sc_cipher_ctx, key);
7330 smemclr(key, ssh->sccipher->padded_keybytes);
7333 key = ssh2_mkkey(ssh, s->K, s->exchange_hash, 'B',
7334 ssh->sccipher->blksize);
7335 ssh->sccipher->setiv(ssh->sc_cipher_ctx, key);
7336 smemclr(key, ssh->sccipher->blksize);
7342 key = ssh2_mkkey(ssh, s->K, s->exchange_hash, 'F',
7343 ssh->scmac->keylen);
7344 ssh->scmac->setkey(ssh->sc_mac_ctx, key);
7345 smemclr(key, ssh->scmac->keylen);
7349 logeventf(ssh, "Initialised %.200s server->client encryption",
7350 ssh->sccipher->text_name);
7352 logeventf(ssh, "Initialised %.200s server->client MAC algorithm%s%s",
7353 ssh->scmac->text_name,
7354 ssh->scmac_etm ? " (in ETM mode)" : "",
7355 ssh->sccipher->required_mac ? " (required by cipher)" : "");
7356 if (ssh->sccomp->text_name)
7357 logeventf(ssh, "Initialised %s decompression",
7358 ssh->sccomp->text_name);
7361 * Free shared secret.
7366 * Key exchange is over. Loop straight back round if we have a
7367 * deferred rekey reason.
7369 if (ssh->deferred_rekey_reason) {
7370 logevent(ssh->deferred_rekey_reason);
7372 ssh->deferred_rekey_reason = NULL;
7373 goto begin_key_exchange;
7377 * Otherwise, schedule a timer for our next rekey.
7379 ssh->kex_in_progress = FALSE;
7380 ssh->last_rekey = GETTICKCOUNT();
7381 if (conf_get_int(ssh->conf, CONF_ssh_rekey_time) != 0)
7382 ssh->next_rekey = schedule_timer(conf_get_int(ssh->conf, CONF_ssh_rekey_time)*60*TICKSPERSEC,
7386 * Now we're encrypting. Begin returning 1 to the protocol main
7387 * function so that other things can run on top of the
7388 * transport. If we ever see a KEXINIT, we must go back to the
7391 * We _also_ go back to the start if we see pktin==NULL and
7392 * inlen negative, because this is a special signal meaning
7393 * `initiate client-driven rekey', and `in' contains a message
7394 * giving the reason for the rekey.
7396 * inlen==-1 means always initiate a rekey;
7397 * inlen==-2 means that userauth has completed successfully and
7398 * we should consider rekeying (for delayed compression).
7400 while (!((pktin && pktin->type == SSH2_MSG_KEXINIT) ||
7401 (!pktin && inlen < 0))) {
7403 if (!ssh->protocol_initial_phase_done) {
7404 ssh->protocol_initial_phase_done = TRUE;
7406 * Allow authconn to initialise itself.
7408 do_ssh2_authconn(ssh, NULL, 0, NULL);
7413 logevent("Server initiated key re-exchange");
7417 * authconn has seen a USERAUTH_SUCCEEDED. Time to enable
7418 * delayed compression, if it's available.
7420 * draft-miller-secsh-compression-delayed-00 says that you
7421 * negotiate delayed compression in the first key exchange, and
7422 * both sides start compressing when the server has sent
7423 * USERAUTH_SUCCESS. This has a race condition -- the server
7424 * can't know when the client has seen it, and thus which incoming
7425 * packets it should treat as compressed.
7427 * Instead, we do the initial key exchange without offering the
7428 * delayed methods, but note if the server offers them; when we
7429 * get here, if a delayed method was available that was higher
7430 * on our list than what we got, we initiate a rekey in which we
7431 * _do_ list the delayed methods (and hopefully get it as a
7432 * result). Subsequent rekeys will do the same.
7434 assert(!s->userauth_succeeded); /* should only happen once */
7435 s->userauth_succeeded = TRUE;
7436 if (!s->pending_compression)
7437 /* Can't see any point rekeying. */
7438 goto wait_for_rekey; /* this is utterly horrid */
7439 /* else fall through to rekey... */
7440 s->pending_compression = FALSE;
7443 * Now we've decided to rekey.
7445 * Special case: if the server bug is set that doesn't
7446 * allow rekeying, we give a different log message and
7447 * continue waiting. (If such a server _initiates_ a rekey,
7448 * we process it anyway!)
7450 if ((ssh->remote_bugs & BUG_SSH2_REKEY)) {
7451 logeventf(ssh, "Server bug prevents key re-exchange (%s)",
7453 /* Reset the counters, so that at least this message doesn't
7454 * hit the event log _too_ often. */
7455 ssh->outgoing_data_size = 0;
7456 ssh->incoming_data_size = 0;
7457 if (conf_get_int(ssh->conf, CONF_ssh_rekey_time) != 0) {
7459 schedule_timer(conf_get_int(ssh->conf, CONF_ssh_rekey_time)*60*TICKSPERSEC,
7462 goto wait_for_rekey; /* this is still utterly horrid */
7464 logeventf(ssh, "Initiating key re-exchange (%s)", (char *)in);
7467 goto begin_key_exchange;
7473 * Add data to an SSH-2 channel output buffer.
7475 static void ssh2_add_channel_data(struct ssh_channel *c, const char *buf,
7478 bufchain_add(&c->v.v2.outbuffer, buf, len);
7482 * Attempt to send data on an SSH-2 channel.
7484 static int ssh2_try_send(struct ssh_channel *c)
7487 struct Packet *pktout;
7490 while (c->v.v2.remwindow > 0 && bufchain_size(&c->v.v2.outbuffer) > 0) {
7493 bufchain_prefix(&c->v.v2.outbuffer, &data, &len);
7494 if ((unsigned)len > c->v.v2.remwindow)
7495 len = c->v.v2.remwindow;
7496 if ((unsigned)len > c->v.v2.remmaxpkt)
7497 len = c->v.v2.remmaxpkt;
7498 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_DATA);
7499 ssh2_pkt_adduint32(pktout, c->remoteid);
7500 ssh2_pkt_addstring_start(pktout);
7501 ssh2_pkt_addstring_data(pktout, data, len);
7502 ssh2_pkt_send(ssh, pktout);
7503 bufchain_consume(&c->v.v2.outbuffer, len);
7504 c->v.v2.remwindow -= len;
7508 * After having sent as much data as we can, return the amount
7511 ret = bufchain_size(&c->v.v2.outbuffer);
7514 * And if there's no data pending but we need to send an EOF, send
7517 if (!ret && c->pending_eof)
7518 ssh_channel_try_eof(c);
7523 static void ssh2_try_send_and_unthrottle(Ssh ssh, struct ssh_channel *c)
7526 if (c->closes & CLOSES_SENT_EOF)
7527 return; /* don't send on channels we've EOFed */
7528 bufsize = ssh2_try_send(c);
7531 case CHAN_MAINSESSION:
7532 /* stdin need not receive an unthrottle
7533 * notification since it will be polled */
7536 x11_unthrottle(c->u.x11.xconn);
7539 /* agent sockets are request/response and need no
7540 * buffer management */
7543 pfd_unthrottle(c->u.pfd.pf);
7549 static int ssh_is_simple(Ssh ssh)
7552 * We use the 'simple' variant of the SSH protocol if we're asked
7553 * to, except not if we're also doing connection-sharing (either
7554 * tunnelling our packets over an upstream or expecting to be
7555 * tunnelled over ourselves), since then the assumption that we
7556 * have only one channel to worry about is not true after all.
7558 return (conf_get_int(ssh->conf, CONF_ssh_simple) &&
7559 !ssh->bare_connection && !ssh->connshare);
7563 * Set up most of a new ssh_channel for SSH-2.
7565 static void ssh2_channel_init(struct ssh_channel *c)
7568 c->localid = alloc_channel_id(ssh);
7570 c->pending_eof = FALSE;
7571 c->throttling_conn = FALSE;
7572 c->v.v2.locwindow = c->v.v2.locmaxwin = c->v.v2.remlocwin =
7573 ssh_is_simple(ssh) ? OUR_V2_BIGWIN : OUR_V2_WINSIZE;
7574 c->v.v2.chanreq_head = NULL;
7575 c->v.v2.throttle_state = UNTHROTTLED;
7576 bufchain_init(&c->v.v2.outbuffer);
7580 * Construct the common parts of a CHANNEL_OPEN.
7582 static struct Packet *ssh2_chanopen_init(struct ssh_channel *c,
7585 struct Packet *pktout;
7587 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN);
7588 ssh2_pkt_addstring(pktout, type);
7589 ssh2_pkt_adduint32(pktout, c->localid);
7590 ssh2_pkt_adduint32(pktout, c->v.v2.locwindow);/* our window size */
7591 ssh2_pkt_adduint32(pktout, OUR_V2_MAXPKT); /* our max pkt size */
7596 * CHANNEL_FAILURE doesn't come with any indication of what message
7597 * caused it, so we have to keep track of the outstanding
7598 * CHANNEL_REQUESTs ourselves.
7600 static void ssh2_queue_chanreq_handler(struct ssh_channel *c,
7601 cchandler_fn_t handler, void *ctx)
7603 struct outstanding_channel_request *ocr =
7604 snew(struct outstanding_channel_request);
7606 assert(!(c->closes & (CLOSES_SENT_CLOSE | CLOSES_RCVD_CLOSE)));
7607 ocr->handler = handler;
7610 if (!c->v.v2.chanreq_head)
7611 c->v.v2.chanreq_head = ocr;
7613 c->v.v2.chanreq_tail->next = ocr;
7614 c->v.v2.chanreq_tail = ocr;
7618 * Construct the common parts of a CHANNEL_REQUEST. If handler is not
7619 * NULL then a reply will be requested and the handler will be called
7620 * when it arrives. The returned packet is ready to have any
7621 * request-specific data added and be sent. Note that if a handler is
7622 * provided, it's essential that the request actually be sent.
7624 * The handler will usually be passed the response packet in pktin. If
7625 * pktin is NULL, this means that no reply will ever be forthcoming
7626 * (e.g. because the entire connection is being destroyed, or because
7627 * the server initiated channel closure before we saw the response)
7628 * and the handler should free any storage it's holding.
7630 static struct Packet *ssh2_chanreq_init(struct ssh_channel *c,
7632 cchandler_fn_t handler, void *ctx)
7634 struct Packet *pktout;
7636 assert(!(c->closes & (CLOSES_SENT_CLOSE | CLOSES_RCVD_CLOSE)));
7637 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
7638 ssh2_pkt_adduint32(pktout, c->remoteid);
7639 ssh2_pkt_addstring(pktout, type);
7640 ssh2_pkt_addbool(pktout, handler != NULL);
7641 if (handler != NULL)
7642 ssh2_queue_chanreq_handler(c, handler, ctx);
7647 * Potentially enlarge the window on an SSH-2 channel.
7649 static void ssh2_handle_winadj_response(struct ssh_channel *, struct Packet *,
7651 static void ssh2_set_window(struct ssh_channel *c, int newwin)
7656 * Never send WINDOW_ADJUST for a channel that the remote side has
7657 * already sent EOF on; there's no point, since it won't be
7658 * sending any more data anyway. Ditto if _we've_ already sent
7661 if (c->closes & (CLOSES_RCVD_EOF | CLOSES_SENT_CLOSE))
7665 * Also, never widen the window for an X11 channel when we're
7666 * still waiting to see its initial auth and may yet hand it off
7669 if (c->type == CHAN_X11 && c->u.x11.initial)
7673 * If the remote end has a habit of ignoring maxpkt, limit the
7674 * window so that it has no choice (assuming it doesn't ignore the
7677 if ((ssh->remote_bugs & BUG_SSH2_MAXPKT) && newwin > OUR_V2_MAXPKT)
7678 newwin = OUR_V2_MAXPKT;
7681 * Only send a WINDOW_ADJUST if there's significantly more window
7682 * available than the other end thinks there is. This saves us
7683 * sending a WINDOW_ADJUST for every character in a shell session.
7685 * "Significant" is arbitrarily defined as half the window size.
7687 if (newwin / 2 >= c->v.v2.locwindow) {
7688 struct Packet *pktout;
7692 * In order to keep track of how much window the client
7693 * actually has available, we'd like it to acknowledge each
7694 * WINDOW_ADJUST. We can't do that directly, so we accompany
7695 * it with a CHANNEL_REQUEST that has to be acknowledged.
7697 * This is only necessary if we're opening the window wide.
7698 * If we're not, then throughput is being constrained by
7699 * something other than the maximum window size anyway.
7701 if (newwin == c->v.v2.locmaxwin &&
7702 !(ssh->remote_bugs & BUG_CHOKES_ON_WINADJ)) {
7703 up = snew(unsigned);
7704 *up = newwin - c->v.v2.locwindow;
7705 pktout = ssh2_chanreq_init(c, "winadj@putty.projects.tartarus.org",
7706 ssh2_handle_winadj_response, up);
7707 ssh2_pkt_send(ssh, pktout);
7709 if (c->v.v2.throttle_state != UNTHROTTLED)
7710 c->v.v2.throttle_state = UNTHROTTLING;
7712 /* Pretend the WINDOW_ADJUST was acked immediately. */
7713 c->v.v2.remlocwin = newwin;
7714 c->v.v2.throttle_state = THROTTLED;
7716 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
7717 ssh2_pkt_adduint32(pktout, c->remoteid);
7718 ssh2_pkt_adduint32(pktout, newwin - c->v.v2.locwindow);
7719 ssh2_pkt_send(ssh, pktout);
7720 c->v.v2.locwindow = newwin;
7725 * Find the channel associated with a message. If there's no channel,
7726 * or it's not properly open, make a noise about it and return NULL.
7728 static struct ssh_channel *ssh2_channel_msg(Ssh ssh, struct Packet *pktin)
7730 unsigned localid = ssh_pkt_getuint32(pktin);
7731 struct ssh_channel *c;
7733 c = find234(ssh->channels, &localid, ssh_channelfind);
7735 (c->type != CHAN_SHARING && c->halfopen &&
7736 pktin->type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION &&
7737 pktin->type != SSH2_MSG_CHANNEL_OPEN_FAILURE)) {
7738 char *buf = dupprintf("Received %s for %s channel %u",
7739 ssh2_pkt_type(ssh->pkt_kctx, ssh->pkt_actx,
7741 c ? "half-open" : "nonexistent", localid);
7742 ssh_disconnect(ssh, NULL, buf, SSH2_DISCONNECT_PROTOCOL_ERROR, FALSE);
7749 static void ssh2_handle_winadj_response(struct ssh_channel *c,
7750 struct Packet *pktin, void *ctx)
7752 unsigned *sizep = ctx;
7755 * Winadj responses should always be failures. However, at least
7756 * one server ("boks_sshd") is known to return SUCCESS for channel
7757 * requests it's never heard of, such as "winadj@putty". Raised
7758 * with foxt.com as bug 090916-090424, but for the sake of a quiet
7759 * life, we don't worry about what kind of response we got.
7762 c->v.v2.remlocwin += *sizep;
7765 * winadj messages are only sent when the window is fully open, so
7766 * if we get an ack of one, we know any pending unthrottle is
7769 if (c->v.v2.throttle_state == UNTHROTTLING)
7770 c->v.v2.throttle_state = UNTHROTTLED;
7773 static void ssh2_msg_channel_response(Ssh ssh, struct Packet *pktin)
7775 struct ssh_channel *c = ssh2_channel_msg(ssh, pktin);
7776 struct outstanding_channel_request *ocr;
7779 if (c->type == CHAN_SHARING) {
7780 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
7781 pktin->body, pktin->length);
7784 ocr = c->v.v2.chanreq_head;
7786 ssh2_msg_unexpected(ssh, pktin);
7789 ocr->handler(c, pktin, ocr->ctx);
7790 c->v.v2.chanreq_head = ocr->next;
7793 * We may now initiate channel-closing procedures, if that
7794 * CHANNEL_REQUEST was the last thing outstanding before we send
7797 ssh2_channel_check_close(c);
7800 static void ssh2_msg_channel_window_adjust(Ssh ssh, struct Packet *pktin)
7802 struct ssh_channel *c;
7803 c = ssh2_channel_msg(ssh, pktin);
7806 if (c->type == CHAN_SHARING) {
7807 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
7808 pktin->body, pktin->length);
7811 if (!(c->closes & CLOSES_SENT_EOF)) {
7812 c->v.v2.remwindow += ssh_pkt_getuint32(pktin);
7813 ssh2_try_send_and_unthrottle(ssh, c);
7817 static void ssh2_msg_channel_data(Ssh ssh, struct Packet *pktin)
7821 struct ssh_channel *c;
7822 c = ssh2_channel_msg(ssh, pktin);
7825 if (c->type == CHAN_SHARING) {
7826 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
7827 pktin->body, pktin->length);
7830 if (pktin->type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
7831 ssh_pkt_getuint32(pktin) != SSH2_EXTENDED_DATA_STDERR)
7832 return; /* extended but not stderr */
7833 ssh_pkt_getstring(pktin, &data, &length);
7836 c->v.v2.locwindow -= length;
7837 c->v.v2.remlocwin -= length;
7839 case CHAN_MAINSESSION:
7841 from_backend(ssh->frontend, pktin->type ==
7842 SSH2_MSG_CHANNEL_EXTENDED_DATA,
7846 bufsize = x11_send(c->u.x11.xconn, data, length);
7849 bufsize = pfd_send(c->u.pfd.pf, data, length);
7852 while (length > 0) {
7853 if (c->u.a.lensofar < 4) {
7854 unsigned int l = min(4 - c->u.a.lensofar,
7856 memcpy(c->u.a.msglen + c->u.a.lensofar,
7860 c->u.a.lensofar += l;
7862 if (c->u.a.lensofar == 4) {
7864 4 + GET_32BIT(c->u.a.msglen);
7865 c->u.a.message = snewn(c->u.a.totallen,
7867 memcpy(c->u.a.message, c->u.a.msglen, 4);
7869 if (c->u.a.lensofar >= 4 && length > 0) {
7871 min(c->u.a.totallen - c->u.a.lensofar,
7873 memcpy(c->u.a.message + c->u.a.lensofar,
7877 c->u.a.lensofar += l;
7879 if (c->u.a.lensofar == c->u.a.totallen) {
7882 c->u.a.outstanding_requests++;
7883 if (agent_query(c->u.a.message,
7886 ssh_agentf_callback, c))
7887 ssh_agentf_callback(c, reply, replylen);
7888 sfree(c->u.a.message);
7889 c->u.a.message = NULL;
7890 c->u.a.lensofar = 0;
7897 * If it looks like the remote end hit the end of its window,
7898 * and we didn't want it to do that, think about using a
7901 if (c->v.v2.remlocwin <= 0 && c->v.v2.throttle_state == UNTHROTTLED &&
7902 c->v.v2.locmaxwin < 0x40000000)
7903 c->v.v2.locmaxwin += OUR_V2_WINSIZE;
7905 * If we are not buffering too much data,
7906 * enlarge the window again at the remote side.
7907 * If we are buffering too much, we may still
7908 * need to adjust the window if the server's
7911 ssh2_set_window(c, bufsize < c->v.v2.locmaxwin ?
7912 c->v.v2.locmaxwin - bufsize : 0);
7914 * If we're either buffering way too much data, or if we're
7915 * buffering anything at all and we're in "simple" mode,
7916 * throttle the whole channel.
7918 if ((bufsize > c->v.v2.locmaxwin || (ssh_is_simple(ssh) && bufsize>0))
7919 && !c->throttling_conn) {
7920 c->throttling_conn = 1;
7921 ssh_throttle_conn(ssh, +1);
7926 static void ssh_check_termination(Ssh ssh)
7928 if (ssh->version == 2 &&
7929 !conf_get_int(ssh->conf, CONF_ssh_no_shell) &&
7930 (ssh->channels && count234(ssh->channels) == 0) &&
7931 !(ssh->connshare && share_ndownstreams(ssh->connshare) > 0)) {
7933 * We used to send SSH_MSG_DISCONNECT here, because I'd
7934 * believed that _every_ conforming SSH-2 connection had to
7935 * end with a disconnect being sent by at least one side;
7936 * apparently I was wrong and it's perfectly OK to
7937 * unceremoniously slam the connection shut when you're done,
7938 * and indeed OpenSSH feels this is more polite than sending a
7939 * DISCONNECT. So now we don't.
7941 ssh_disconnect(ssh, "All channels closed", NULL, 0, TRUE);
7945 void ssh_sharing_downstream_connected(Ssh ssh, unsigned id,
7946 const char *peerinfo)
7949 logeventf(ssh, "Connection sharing downstream #%u connected from %s",
7952 logeventf(ssh, "Connection sharing downstream #%u connected", id);
7955 void ssh_sharing_downstream_disconnected(Ssh ssh, unsigned id)
7957 logeventf(ssh, "Connection sharing downstream #%u disconnected", id);
7958 ssh_check_termination(ssh);
7961 void ssh_sharing_logf(Ssh ssh, unsigned id, const char *logfmt, ...)
7966 va_start(ap, logfmt);
7967 buf = dupvprintf(logfmt, ap);
7970 logeventf(ssh, "Connection sharing downstream #%u: %s", id, buf);
7972 logeventf(ssh, "Connection sharing: %s", buf);
7976 static void ssh_channel_destroy(struct ssh_channel *c)
7981 case CHAN_MAINSESSION:
7982 ssh->mainchan = NULL;
7983 update_specials_menu(ssh->frontend);
7986 if (c->u.x11.xconn != NULL)
7987 x11_close(c->u.x11.xconn);
7988 logevent("Forwarded X11 connection terminated");
7991 sfree(c->u.a.message);
7994 if (c->u.pfd.pf != NULL)
7995 pfd_close(c->u.pfd.pf);
7996 logevent("Forwarded port closed");
8000 del234(ssh->channels, c);
8001 if (ssh->version == 2) {
8002 bufchain_clear(&c->v.v2.outbuffer);
8003 assert(c->v.v2.chanreq_head == NULL);
8008 * If that was the last channel left open, we might need to
8011 ssh_check_termination(ssh);
8014 static void ssh2_channel_check_close(struct ssh_channel *c)
8017 struct Packet *pktout;
8021 * If we've sent out our own CHANNEL_OPEN but not yet seen
8022 * either OPEN_CONFIRMATION or OPEN_FAILURE in response, then
8023 * it's too early to be sending close messages of any kind.
8028 if ((!((CLOSES_SENT_EOF | CLOSES_RCVD_EOF) & ~c->closes) ||
8029 c->type == CHAN_ZOMBIE) &&
8030 !c->v.v2.chanreq_head &&
8031 !(c->closes & CLOSES_SENT_CLOSE)) {
8033 * We have both sent and received EOF (or the channel is a
8034 * zombie), and we have no outstanding channel requests, which
8035 * means the channel is in final wind-up. But we haven't sent
8036 * CLOSE, so let's do so now.
8038 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE);
8039 ssh2_pkt_adduint32(pktout, c->remoteid);
8040 ssh2_pkt_send(ssh, pktout);
8041 c->closes |= CLOSES_SENT_EOF | CLOSES_SENT_CLOSE;
8044 if (!((CLOSES_SENT_CLOSE | CLOSES_RCVD_CLOSE) & ~c->closes)) {
8045 assert(c->v.v2.chanreq_head == NULL);
8047 * We have both sent and received CLOSE, which means we're
8048 * completely done with the channel.
8050 ssh_channel_destroy(c);
8054 static void ssh2_channel_got_eof(struct ssh_channel *c)
8056 if (c->closes & CLOSES_RCVD_EOF)
8057 return; /* already seen EOF */
8058 c->closes |= CLOSES_RCVD_EOF;
8060 if (c->type == CHAN_X11) {
8061 x11_send_eof(c->u.x11.xconn);
8062 } else if (c->type == CHAN_AGENT) {
8063 if (c->u.a.outstanding_requests == 0) {
8064 /* Manufacture an outgoing EOF in response to the incoming one. */
8065 sshfwd_write_eof(c);
8067 } else if (c->type == CHAN_SOCKDATA) {
8068 pfd_send_eof(c->u.pfd.pf);
8069 } else if (c->type == CHAN_MAINSESSION) {
8072 if (!ssh->sent_console_eof &&
8073 (from_backend_eof(ssh->frontend) || ssh->got_pty)) {
8075 * Either from_backend_eof told us that the front end
8076 * wants us to close the outgoing side of the connection
8077 * as soon as we see EOF from the far end, or else we've
8078 * unilaterally decided to do that because we've allocated
8079 * a remote pty and hence EOF isn't a particularly
8080 * meaningful concept.
8082 sshfwd_write_eof(c);
8084 ssh->sent_console_eof = TRUE;
8087 ssh2_channel_check_close(c);
8090 static void ssh2_msg_channel_eof(Ssh ssh, struct Packet *pktin)
8092 struct ssh_channel *c;
8094 c = ssh2_channel_msg(ssh, pktin);
8097 if (c->type == CHAN_SHARING) {
8098 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
8099 pktin->body, pktin->length);
8102 ssh2_channel_got_eof(c);
8105 static void ssh2_msg_channel_close(Ssh ssh, struct Packet *pktin)
8107 struct ssh_channel *c;
8109 c = ssh2_channel_msg(ssh, pktin);
8112 if (c->type == CHAN_SHARING) {
8113 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
8114 pktin->body, pktin->length);
8119 * When we receive CLOSE on a channel, we assume it comes with an
8120 * implied EOF if we haven't seen EOF yet.
8122 ssh2_channel_got_eof(c);
8124 if (!(ssh->remote_bugs & BUG_SENDS_LATE_REQUEST_REPLY)) {
8126 * It also means we stop expecting to see replies to any
8127 * outstanding channel requests, so clean those up too.
8128 * (ssh_chanreq_init will enforce by assertion that we don't
8129 * subsequently put anything back on this list.)
8131 while (c->v.v2.chanreq_head) {
8132 struct outstanding_channel_request *ocr = c->v.v2.chanreq_head;
8133 ocr->handler(c, NULL, ocr->ctx);
8134 c->v.v2.chanreq_head = ocr->next;
8140 * And we also send an outgoing EOF, if we haven't already, on the
8141 * assumption that CLOSE is a pretty forceful announcement that
8142 * the remote side is doing away with the entire channel. (If it
8143 * had wanted to send us EOF and continue receiving data from us,
8144 * it would have just sent CHANNEL_EOF.)
8146 if (!(c->closes & CLOSES_SENT_EOF)) {
8148 * Make sure we don't read any more from whatever our local
8149 * data source is for this channel.
8152 case CHAN_MAINSESSION:
8153 ssh->send_ok = 0; /* stop trying to read from stdin */
8156 x11_override_throttle(c->u.x11.xconn, 1);
8159 pfd_override_throttle(c->u.pfd.pf, 1);
8164 * Abandon any buffered data we still wanted to send to this
8165 * channel. Receiving a CHANNEL_CLOSE is an indication that
8166 * the server really wants to get on and _destroy_ this
8167 * channel, and it isn't going to send us any further
8168 * WINDOW_ADJUSTs to permit us to send pending stuff.
8170 bufchain_clear(&c->v.v2.outbuffer);
8173 * Send outgoing EOF.
8175 sshfwd_write_eof(c);
8179 * Now process the actual close.
8181 if (!(c->closes & CLOSES_RCVD_CLOSE)) {
8182 c->closes |= CLOSES_RCVD_CLOSE;
8183 ssh2_channel_check_close(c);
8187 static void ssh2_msg_channel_open_confirmation(Ssh ssh, struct Packet *pktin)
8189 struct ssh_channel *c;
8191 c = ssh2_channel_msg(ssh, pktin);
8194 if (c->type == CHAN_SHARING) {
8195 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
8196 pktin->body, pktin->length);
8199 assert(c->halfopen); /* ssh2_channel_msg will have enforced this */
8200 c->remoteid = ssh_pkt_getuint32(pktin);
8201 c->halfopen = FALSE;
8202 c->v.v2.remwindow = ssh_pkt_getuint32(pktin);
8203 c->v.v2.remmaxpkt = ssh_pkt_getuint32(pktin);
8205 if (c->type == CHAN_SOCKDATA_DORMANT) {
8206 c->type = CHAN_SOCKDATA;
8208 pfd_confirm(c->u.pfd.pf);
8209 } else if (c->type == CHAN_ZOMBIE) {
8211 * This case can occur if a local socket error occurred
8212 * between us sending out CHANNEL_OPEN and receiving
8213 * OPEN_CONFIRMATION. In this case, all we can do is
8214 * immediately initiate close proceedings now that we know the
8215 * server's id to put in the close message.
8217 ssh2_channel_check_close(c);
8220 * We never expect to receive OPEN_CONFIRMATION for any
8221 * *other* channel type (since only local-to-remote port
8222 * forwardings cause us to send CHANNEL_OPEN after the main
8223 * channel is live - all other auxiliary channel types are
8224 * initiated from the server end). It's safe to enforce this
8225 * by assertion rather than by ssh_disconnect, because the
8226 * real point is that we never constructed a half-open channel
8227 * structure in the first place with any type other than the
8230 assert(!"Funny channel type in ssh2_msg_channel_open_confirmation");
8234 ssh_channel_try_eof(c); /* in case we had a pending EOF */
8237 static void ssh2_msg_channel_open_failure(Ssh ssh, struct Packet *pktin)
8239 static const char *const reasons[] = {
8240 "<unknown reason code>",
8241 "Administratively prohibited",
8243 "Unknown channel type",
8244 "Resource shortage",
8246 unsigned reason_code;
8247 char *reason_string;
8249 struct ssh_channel *c;
8251 c = ssh2_channel_msg(ssh, pktin);
8254 if (c->type == CHAN_SHARING) {
8255 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
8256 pktin->body, pktin->length);
8259 assert(c->halfopen); /* ssh2_channel_msg will have enforced this */
8261 if (c->type == CHAN_SOCKDATA_DORMANT) {
8262 reason_code = ssh_pkt_getuint32(pktin);
8263 if (reason_code >= lenof(reasons))
8264 reason_code = 0; /* ensure reasons[reason_code] in range */
8265 ssh_pkt_getstring(pktin, &reason_string, &reason_length);
8266 logeventf(ssh, "Forwarded connection refused by server: %s [%.*s]",
8267 reasons[reason_code], reason_length, reason_string);
8269 pfd_close(c->u.pfd.pf);
8270 } else if (c->type == CHAN_ZOMBIE) {
8272 * This case can occur if a local socket error occurred
8273 * between us sending out CHANNEL_OPEN and receiving
8274 * OPEN_FAILURE. In this case, we need do nothing except allow
8275 * the code below to throw the half-open channel away.
8279 * We never expect to receive OPEN_FAILURE for any *other*
8280 * channel type (since only local-to-remote port forwardings
8281 * cause us to send CHANNEL_OPEN after the main channel is
8282 * live - all other auxiliary channel types are initiated from
8283 * the server end). It's safe to enforce this by assertion
8284 * rather than by ssh_disconnect, because the real point is
8285 * that we never constructed a half-open channel structure in
8286 * the first place with any type other than the above.
8288 assert(!"Funny channel type in ssh2_msg_channel_open_failure");
8291 del234(ssh->channels, c);
8295 static void ssh2_msg_channel_request(Ssh ssh, struct Packet *pktin)
8298 int typelen, want_reply;
8299 int reply = SSH2_MSG_CHANNEL_FAILURE; /* default */
8300 struct ssh_channel *c;
8301 struct Packet *pktout;
8303 c = ssh2_channel_msg(ssh, pktin);
8306 if (c->type == CHAN_SHARING) {
8307 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
8308 pktin->body, pktin->length);
8311 ssh_pkt_getstring(pktin, &type, &typelen);
8312 want_reply = ssh2_pkt_getbool(pktin);
8314 if (c->closes & CLOSES_SENT_CLOSE) {
8316 * We don't reply to channel requests after we've sent
8317 * CHANNEL_CLOSE for the channel, because our reply might
8318 * cross in the network with the other side's CHANNEL_CLOSE
8319 * and arrive after they have wound the channel up completely.
8325 * Having got the channel number, we now look at
8326 * the request type string to see if it's something
8329 if (c == ssh->mainchan) {
8331 * We recognise "exit-status" and "exit-signal" on
8332 * the primary channel.
8334 if (typelen == 11 &&
8335 !memcmp(type, "exit-status", 11)) {
8337 ssh->exitcode = ssh_pkt_getuint32(pktin);
8338 logeventf(ssh, "Server sent command exit status %d",
8340 reply = SSH2_MSG_CHANNEL_SUCCESS;
8342 } else if (typelen == 11 &&
8343 !memcmp(type, "exit-signal", 11)) {
8345 int is_plausible = TRUE, is_int = FALSE;
8346 char *fmt_sig = NULL, *fmt_msg = NULL;
8348 int msglen = 0, core = FALSE;
8349 /* ICK: older versions of OpenSSH (e.g. 3.4p1)
8350 * provide an `int' for the signal, despite its
8351 * having been a `string' in the drafts of RFC 4254 since at
8352 * least 2001. (Fixed in session.c 1.147.) Try to
8353 * infer which we can safely parse it as. */
8355 unsigned char *p = pktin->body +
8357 long len = pktin->length - pktin->savedpos;
8358 unsigned long num = GET_32BIT(p); /* what is it? */
8359 /* If it's 0, it hardly matters; assume string */
8363 int maybe_int = FALSE, maybe_str = FALSE;
8364 #define CHECK_HYPOTHESIS(offset, result) \
8367 int q = toint(offset); \
8368 if (q >= 0 && q+4 <= len) { \
8369 q = toint(q + 4 + GET_32BIT(p+q)); \
8370 if (q >= 0 && q+4 <= len && \
8371 ((q = toint(q + 4 + GET_32BIT(p+q))) != 0) && \
8376 CHECK_HYPOTHESIS(4+1, maybe_int);
8377 CHECK_HYPOTHESIS(4+num+1, maybe_str);
8378 #undef CHECK_HYPOTHESIS
8379 if (maybe_int && !maybe_str)
8381 else if (!maybe_int && maybe_str)
8384 /* Crikey. Either or neither. Panic. */
8385 is_plausible = FALSE;
8388 ssh->exitcode = 128; /* means `unknown signal' */
8391 /* Old non-standard OpenSSH. */
8392 int signum = ssh_pkt_getuint32(pktin);
8393 fmt_sig = dupprintf(" %d", signum);
8394 ssh->exitcode = 128 + signum;
8396 /* As per RFC 4254. */
8399 ssh_pkt_getstring(pktin, &sig, &siglen);
8400 /* Signal name isn't supposed to be blank, but
8401 * let's cope gracefully if it is. */
8403 fmt_sig = dupprintf(" \"%.*s\"",
8408 * Really hideous method of translating the
8409 * signal description back into a locally
8410 * meaningful number.
8415 #define TRANSLATE_SIGNAL(s) \
8416 else if (siglen == lenof(#s)-1 && !memcmp(sig, #s, siglen)) \
8417 ssh->exitcode = 128 + SIG ## s
8419 TRANSLATE_SIGNAL(ABRT);
8422 TRANSLATE_SIGNAL(ALRM);
8425 TRANSLATE_SIGNAL(FPE);
8428 TRANSLATE_SIGNAL(HUP);
8431 TRANSLATE_SIGNAL(ILL);
8434 TRANSLATE_SIGNAL(INT);
8437 TRANSLATE_SIGNAL(KILL);
8440 TRANSLATE_SIGNAL(PIPE);
8443 TRANSLATE_SIGNAL(QUIT);
8446 TRANSLATE_SIGNAL(SEGV);
8449 TRANSLATE_SIGNAL(TERM);
8452 TRANSLATE_SIGNAL(USR1);
8455 TRANSLATE_SIGNAL(USR2);
8457 #undef TRANSLATE_SIGNAL
8459 ssh->exitcode = 128;
8461 core = ssh2_pkt_getbool(pktin);
8462 ssh_pkt_getstring(pktin, &msg, &msglen);
8464 fmt_msg = dupprintf(" (\"%.*s\")", msglen, msg);
8466 /* ignore lang tag */
8467 } /* else don't attempt to parse */
8468 logeventf(ssh, "Server exited on signal%s%s%s",
8469 fmt_sig ? fmt_sig : "",
8470 core ? " (core dumped)" : "",
8471 fmt_msg ? fmt_msg : "");
8474 reply = SSH2_MSG_CHANNEL_SUCCESS;
8479 * This is a channel request we don't know
8480 * about, so we now either ignore the request
8481 * or respond with CHANNEL_FAILURE, depending
8484 reply = SSH2_MSG_CHANNEL_FAILURE;
8487 pktout = ssh2_pkt_init(reply);
8488 ssh2_pkt_adduint32(pktout, c->remoteid);
8489 ssh2_pkt_send(ssh, pktout);
8493 static void ssh2_msg_global_request(Ssh ssh, struct Packet *pktin)
8496 int typelen, want_reply;
8497 struct Packet *pktout;
8499 ssh_pkt_getstring(pktin, &type, &typelen);
8500 want_reply = ssh2_pkt_getbool(pktin);
8503 * We currently don't support any global requests
8504 * at all, so we either ignore the request or
8505 * respond with REQUEST_FAILURE, depending on
8509 pktout = ssh2_pkt_init(SSH2_MSG_REQUEST_FAILURE);
8510 ssh2_pkt_send(ssh, pktout);
8514 struct X11FakeAuth *ssh_sharing_add_x11_display(Ssh ssh, int authtype,
8518 struct X11FakeAuth *auth;
8521 * Make up a new set of fake X11 auth data, and add it to the tree
8522 * of currently valid ones with an indication of the sharing
8523 * context that it's relevant to.
8525 auth = x11_invent_fake_auth(ssh->x11authtree, authtype);
8526 auth->share_cs = share_cs;
8527 auth->share_chan = share_chan;
8532 void ssh_sharing_remove_x11_display(Ssh ssh, struct X11FakeAuth *auth)
8534 del234(ssh->x11authtree, auth);
8535 x11_free_fake_auth(auth);
8538 static void ssh2_msg_channel_open(Ssh ssh, struct Packet *pktin)
8545 const char *error = NULL;
8546 struct ssh_channel *c;
8547 unsigned remid, winsize, pktsize;
8548 unsigned our_winsize_override = 0;
8549 struct Packet *pktout;
8551 ssh_pkt_getstring(pktin, &type, &typelen);
8552 c = snew(struct ssh_channel);
8555 remid = ssh_pkt_getuint32(pktin);
8556 winsize = ssh_pkt_getuint32(pktin);
8557 pktsize = ssh_pkt_getuint32(pktin);
8559 if (typelen == 3 && !memcmp(type, "x11", 3)) {
8562 ssh_pkt_getstring(pktin, &peeraddr, &peeraddrlen);
8563 addrstr = snewn(peeraddrlen+1, char);
8564 memcpy(addrstr, peeraddr, peeraddrlen);
8565 addrstr[peeraddrlen] = '\0';
8566 peerport = ssh_pkt_getuint32(pktin);
8568 logeventf(ssh, "Received X11 connect request from %s:%d",
8571 if (!ssh->X11_fwd_enabled && !ssh->connshare)
8572 error = "X11 forwarding is not enabled";
8574 c->u.x11.xconn = x11_init(ssh->x11authtree, c,
8577 c->u.x11.initial = TRUE;
8580 * If we are a connection-sharing upstream, then we should
8581 * initially present a very small window, adequate to take
8582 * the X11 initial authorisation packet but not much more.
8583 * Downstream will then present us a larger window (by
8584 * fiat of the connection-sharing protocol) and we can
8585 * guarantee to send a positive-valued WINDOW_ADJUST.
8588 our_winsize_override = 128;
8590 logevent("Opened X11 forward channel");
8594 } else if (typelen == 15 &&
8595 !memcmp(type, "forwarded-tcpip", 15)) {
8596 struct ssh_rportfwd pf, *realpf;
8599 ssh_pkt_getstring(pktin, &shost, &shostlen);/* skip address */
8600 pf.shost = dupprintf("%.*s", shostlen, shost);
8601 pf.sport = ssh_pkt_getuint32(pktin);
8602 ssh_pkt_getstring(pktin, &peeraddr, &peeraddrlen);
8603 peerport = ssh_pkt_getuint32(pktin);
8604 realpf = find234(ssh->rportfwds, &pf, NULL);
8605 logeventf(ssh, "Received remote port %s:%d open request "
8606 "from %s:%d", pf.shost, pf.sport, peeraddr, peerport);
8609 if (realpf == NULL) {
8610 error = "Remote port is not recognised";
8614 if (realpf->share_ctx) {
8616 * This port forwarding is on behalf of a
8617 * connection-sharing downstream, so abandon our own
8618 * channel-open procedure and just pass the message on
8621 share_got_pkt_from_server(realpf->share_ctx, pktin->type,
8622 pktin->body, pktin->length);
8627 err = pfd_connect(&c->u.pfd.pf, realpf->dhost, realpf->dport,
8628 c, ssh->conf, realpf->pfrec->addressfamily);
8629 logeventf(ssh, "Attempting to forward remote port to "
8630 "%s:%d", realpf->dhost, realpf->dport);
8632 logeventf(ssh, "Port open failed: %s", err);
8634 error = "Port open failed";
8636 logevent("Forwarded port opened successfully");
8637 c->type = CHAN_SOCKDATA;
8640 } else if (typelen == 22 &&
8641 !memcmp(type, "auth-agent@openssh.com", 22)) {
8642 if (!ssh->agentfwd_enabled)
8643 error = "Agent forwarding is not enabled";
8645 c->type = CHAN_AGENT; /* identify channel type */
8646 c->u.a.lensofar = 0;
8647 c->u.a.message = NULL;
8648 c->u.a.outstanding_requests = 0;
8651 error = "Unsupported channel type requested";
8654 c->remoteid = remid;
8655 c->halfopen = FALSE;
8657 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_FAILURE);
8658 ssh2_pkt_adduint32(pktout, c->remoteid);
8659 ssh2_pkt_adduint32(pktout, SSH2_OPEN_CONNECT_FAILED);
8660 ssh2_pkt_addstring(pktout, error);
8661 ssh2_pkt_addstring(pktout, "en"); /* language tag */
8662 ssh2_pkt_send(ssh, pktout);
8663 logeventf(ssh, "Rejected channel open: %s", error);
8666 ssh2_channel_init(c);
8667 c->v.v2.remwindow = winsize;
8668 c->v.v2.remmaxpkt = pktsize;
8669 if (our_winsize_override) {
8670 c->v.v2.locwindow = c->v.v2.locmaxwin = c->v.v2.remlocwin =
8671 our_winsize_override;
8673 add234(ssh->channels, c);
8674 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
8675 ssh2_pkt_adduint32(pktout, c->remoteid);
8676 ssh2_pkt_adduint32(pktout, c->localid);
8677 ssh2_pkt_adduint32(pktout, c->v.v2.locwindow);
8678 ssh2_pkt_adduint32(pktout, OUR_V2_MAXPKT); /* our max pkt size */
8679 ssh2_pkt_send(ssh, pktout);
8683 void sshfwd_x11_sharing_handover(struct ssh_channel *c,
8684 void *share_cs, void *share_chan,
8685 const char *peer_addr, int peer_port,
8686 int endian, int protomajor, int protominor,
8687 const void *initial_data, int initial_len)
8690 * This function is called when we've just discovered that an X
8691 * forwarding channel on which we'd been handling the initial auth
8692 * ourselves turns out to be destined for a connection-sharing
8693 * downstream. So we turn the channel into a CHAN_SHARING, meaning
8694 * that we completely stop tracking windows and buffering data and
8695 * just pass more or less unmodified SSH messages back and forth.
8697 c->type = CHAN_SHARING;
8698 c->u.sharing.ctx = share_cs;
8699 share_setup_x11_channel(share_cs, share_chan,
8700 c->localid, c->remoteid, c->v.v2.remwindow,
8701 c->v.v2.remmaxpkt, c->v.v2.locwindow,
8702 peer_addr, peer_port, endian,
8703 protomajor, protominor,
8704 initial_data, initial_len);
8707 void sshfwd_x11_is_local(struct ssh_channel *c)
8710 * This function is called when we've just discovered that an X
8711 * forwarding channel is _not_ destined for a connection-sharing
8712 * downstream but we're going to handle it ourselves. We stop
8713 * presenting a cautiously small window and go into ordinary data
8716 c->u.x11.initial = FALSE;
8717 ssh2_set_window(c, ssh_is_simple(c->ssh) ? OUR_V2_BIGWIN : OUR_V2_WINSIZE);
8721 * Buffer banner messages for later display at some convenient point,
8722 * if we're going to display them.
8724 static void ssh2_msg_userauth_banner(Ssh ssh, struct Packet *pktin)
8726 /* Arbitrary limit to prevent unbounded inflation of buffer */
8727 if (conf_get_int(ssh->conf, CONF_ssh_show_banner) &&
8728 bufchain_size(&ssh->banner) <= 131072) {
8729 char *banner = NULL;
8731 ssh_pkt_getstring(pktin, &banner, &size);
8733 bufchain_add(&ssh->banner, banner, size);
8737 /* Helper function to deal with sending tty modes for "pty-req" */
8738 static void ssh2_send_ttymode(void *data, char *mode, char *val)
8740 struct Packet *pktout = (struct Packet *)data;
8742 unsigned int arg = 0;
8743 while (strcmp(mode, ssh_ttymodes[i].mode) != 0) i++;
8744 if (i == lenof(ssh_ttymodes)) return;
8745 switch (ssh_ttymodes[i].type) {
8747 arg = ssh_tty_parse_specchar(val);
8750 arg = ssh_tty_parse_boolean(val);
8753 ssh2_pkt_addbyte(pktout, ssh_ttymodes[i].opcode);
8754 ssh2_pkt_adduint32(pktout, arg);
8757 static void ssh2_setup_x11(struct ssh_channel *c, struct Packet *pktin,
8760 struct ssh2_setup_x11_state {
8764 struct Packet *pktout;
8765 crStateP(ssh2_setup_x11_state, ctx);
8769 logevent("Requesting X11 forwarding");
8770 pktout = ssh2_chanreq_init(ssh->mainchan, "x11-req",
8772 ssh2_pkt_addbool(pktout, 0); /* many connections */
8773 ssh2_pkt_addstring(pktout, ssh->x11auth->protoname);
8774 ssh2_pkt_addstring(pktout, ssh->x11auth->datastring);
8775 ssh2_pkt_adduint32(pktout, ssh->x11disp->screennum);
8776 ssh2_pkt_send(ssh, pktout);
8778 /* Wait to be called back with either a response packet, or NULL
8779 * meaning clean up and free our data */
8783 if (pktin->type == SSH2_MSG_CHANNEL_SUCCESS) {
8784 logevent("X11 forwarding enabled");
8785 ssh->X11_fwd_enabled = TRUE;
8787 logevent("X11 forwarding refused");
8793 static void ssh2_setup_agent(struct ssh_channel *c, struct Packet *pktin,
8796 struct ssh2_setup_agent_state {
8800 struct Packet *pktout;
8801 crStateP(ssh2_setup_agent_state, ctx);
8805 logevent("Requesting OpenSSH-style agent forwarding");
8806 pktout = ssh2_chanreq_init(ssh->mainchan, "auth-agent-req@openssh.com",
8807 ssh2_setup_agent, s);
8808 ssh2_pkt_send(ssh, pktout);
8810 /* Wait to be called back with either a response packet, or NULL
8811 * meaning clean up and free our data */
8815 if (pktin->type == SSH2_MSG_CHANNEL_SUCCESS) {
8816 logevent("Agent forwarding enabled");
8817 ssh->agentfwd_enabled = TRUE;
8819 logevent("Agent forwarding refused");
8825 static void ssh2_setup_pty(struct ssh_channel *c, struct Packet *pktin,
8828 struct ssh2_setup_pty_state {
8832 struct Packet *pktout;
8833 crStateP(ssh2_setup_pty_state, ctx);
8837 /* Unpick the terminal-speed string. */
8838 /* XXX perhaps we should allow no speeds to be sent. */
8839 ssh->ospeed = 38400; ssh->ispeed = 38400; /* last-resort defaults */
8840 sscanf(conf_get_str(ssh->conf, CONF_termspeed), "%d,%d", &ssh->ospeed, &ssh->ispeed);
8841 /* Build the pty request. */
8842 pktout = ssh2_chanreq_init(ssh->mainchan, "pty-req",
8844 ssh2_pkt_addstring(pktout, conf_get_str(ssh->conf, CONF_termtype));
8845 ssh2_pkt_adduint32(pktout, ssh->term_width);
8846 ssh2_pkt_adduint32(pktout, ssh->term_height);
8847 ssh2_pkt_adduint32(pktout, 0); /* pixel width */
8848 ssh2_pkt_adduint32(pktout, 0); /* pixel height */
8849 ssh2_pkt_addstring_start(pktout);
8850 parse_ttymodes(ssh, ssh2_send_ttymode, (void *)pktout);
8851 ssh2_pkt_addbyte(pktout, SSH2_TTY_OP_ISPEED);
8852 ssh2_pkt_adduint32(pktout, ssh->ispeed);
8853 ssh2_pkt_addbyte(pktout, SSH2_TTY_OP_OSPEED);
8854 ssh2_pkt_adduint32(pktout, ssh->ospeed);
8855 ssh2_pkt_addstring_data(pktout, "\0", 1); /* TTY_OP_END */
8856 ssh2_pkt_send(ssh, pktout);
8857 ssh->state = SSH_STATE_INTERMED;
8859 /* Wait to be called back with either a response packet, or NULL
8860 * meaning clean up and free our data */
8864 if (pktin->type == SSH2_MSG_CHANNEL_SUCCESS) {
8865 logeventf(ssh, "Allocated pty (ospeed %dbps, ispeed %dbps)",
8866 ssh->ospeed, ssh->ispeed);
8867 ssh->got_pty = TRUE;
8869 c_write_str(ssh, "Server refused to allocate pty\r\n");
8870 ssh->editing = ssh->echoing = 1;
8877 static void ssh2_setup_env(struct ssh_channel *c, struct Packet *pktin,
8880 struct ssh2_setup_env_state {
8882 int num_env, env_left, env_ok;
8885 struct Packet *pktout;
8886 crStateP(ssh2_setup_env_state, ctx);
8891 * Send environment variables.
8893 * Simplest thing here is to send all the requests at once, and
8894 * then wait for a whole bunch of successes or failures.
8900 for (val = conf_get_str_strs(ssh->conf, CONF_environmt, NULL, &key);
8902 val = conf_get_str_strs(ssh->conf, CONF_environmt, key, &key)) {
8903 pktout = ssh2_chanreq_init(ssh->mainchan, "env", ssh2_setup_env, s);
8904 ssh2_pkt_addstring(pktout, key);
8905 ssh2_pkt_addstring(pktout, val);
8906 ssh2_pkt_send(ssh, pktout);
8911 logeventf(ssh, "Sent %d environment variables", s->num_env);
8916 s->env_left = s->num_env;
8918 while (s->env_left > 0) {
8919 /* Wait to be called back with either a response packet,
8920 * or NULL meaning clean up and free our data */
8922 if (!pktin) goto out;
8923 if (pktin->type == SSH2_MSG_CHANNEL_SUCCESS)
8928 if (s->env_ok == s->num_env) {
8929 logevent("All environment variables successfully set");
8930 } else if (s->env_ok == 0) {
8931 logevent("All environment variables refused");
8932 c_write_str(ssh, "Server refused to set environment variables\r\n");
8934 logeventf(ssh, "%d environment variables refused",
8935 s->num_env - s->env_ok);
8936 c_write_str(ssh, "Server refused to set all environment variables\r\n");
8944 * Handle the SSH-2 userauth and connection layers.
8946 static void ssh2_msg_authconn(Ssh ssh, struct Packet *pktin)
8948 do_ssh2_authconn(ssh, NULL, 0, pktin);
8951 static void ssh2_response_authconn(struct ssh_channel *c, struct Packet *pktin,
8955 do_ssh2_authconn(c->ssh, NULL, 0, pktin);
8958 static void do_ssh2_authconn(Ssh ssh, const unsigned char *in, int inlen,
8959 struct Packet *pktin)
8961 struct do_ssh2_authconn_state {
8965 AUTH_TYPE_PUBLICKEY,
8966 AUTH_TYPE_PUBLICKEY_OFFER_LOUD,
8967 AUTH_TYPE_PUBLICKEY_OFFER_QUIET,
8969 AUTH_TYPE_GSSAPI, /* always QUIET */
8970 AUTH_TYPE_KEYBOARD_INTERACTIVE,
8971 AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET
8973 int done_service_req;
8974 int gotit, need_pw, can_pubkey, can_passwd, can_keyb_inter;
8975 int tried_pubkey_config, done_agent;
8980 int kbd_inter_refused;
8981 int we_are_in, userauth_success;
8982 prompts_t *cur_prompt;
8987 void *publickey_blob;
8988 int publickey_bloblen;
8989 int privatekey_available, privatekey_encrypted;
8990 char *publickey_algorithm;
8991 char *publickey_comment;
8992 unsigned char agent_request[5], *agent_response, *agentp;
8993 int agent_responselen;
8994 unsigned char *pkblob_in_agent;
8996 char *pkblob, *alg, *commentp;
8997 int pklen, alglen, commentlen;
8998 int siglen, retlen, len;
8999 char *q, *agentreq, *ret;
9001 struct Packet *pktout;
9004 struct ssh_gss_library *gsslib;
9005 Ssh_gss_ctx gss_ctx;
9006 Ssh_gss_buf gss_buf;
9007 Ssh_gss_buf gss_rcvtok, gss_sndtok;
9008 Ssh_gss_name gss_srv_name;
9009 Ssh_gss_stat gss_stat;
9012 crState(do_ssh2_authconn_state);
9016 /* Register as a handler for all the messages this coroutine handles. */
9017 ssh->packet_dispatch[SSH2_MSG_SERVICE_ACCEPT] = ssh2_msg_authconn;
9018 ssh->packet_dispatch[SSH2_MSG_USERAUTH_REQUEST] = ssh2_msg_authconn;
9019 ssh->packet_dispatch[SSH2_MSG_USERAUTH_FAILURE] = ssh2_msg_authconn;
9020 ssh->packet_dispatch[SSH2_MSG_USERAUTH_SUCCESS] = ssh2_msg_authconn;
9021 ssh->packet_dispatch[SSH2_MSG_USERAUTH_BANNER] = ssh2_msg_authconn;
9022 ssh->packet_dispatch[SSH2_MSG_USERAUTH_PK_OK] = ssh2_msg_authconn;
9023 /* ssh->packet_dispatch[SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ] = ssh2_msg_authconn; duplicate case value */
9024 /* ssh->packet_dispatch[SSH2_MSG_USERAUTH_INFO_REQUEST] = ssh2_msg_authconn; duplicate case value */
9025 ssh->packet_dispatch[SSH2_MSG_USERAUTH_INFO_RESPONSE] = ssh2_msg_authconn;
9026 ssh->packet_dispatch[SSH2_MSG_GLOBAL_REQUEST] = ssh2_msg_authconn;
9027 ssh->packet_dispatch[SSH2_MSG_REQUEST_SUCCESS] = ssh2_msg_authconn;
9028 ssh->packet_dispatch[SSH2_MSG_REQUEST_FAILURE] = ssh2_msg_authconn;
9029 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN] = ssh2_msg_authconn;
9030 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_CONFIRMATION] = ssh2_msg_authconn;
9031 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_FAILURE] = ssh2_msg_authconn;
9032 ssh->packet_dispatch[SSH2_MSG_CHANNEL_WINDOW_ADJUST] = ssh2_msg_authconn;
9033 ssh->packet_dispatch[SSH2_MSG_CHANNEL_DATA] = ssh2_msg_authconn;
9034 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EXTENDED_DATA] = ssh2_msg_authconn;
9035 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EOF] = ssh2_msg_authconn;
9036 ssh->packet_dispatch[SSH2_MSG_CHANNEL_CLOSE] = ssh2_msg_authconn;
9038 s->done_service_req = FALSE;
9039 s->we_are_in = s->userauth_success = FALSE;
9040 s->agent_response = NULL;
9042 s->tried_gssapi = FALSE;
9045 if (!ssh->bare_connection) {
9046 if (!conf_get_int(ssh->conf, CONF_ssh_no_userauth)) {
9048 * Request userauth protocol, and await a response to it.
9050 s->pktout = ssh2_pkt_init(SSH2_MSG_SERVICE_REQUEST);
9051 ssh2_pkt_addstring(s->pktout, "ssh-userauth");
9052 ssh2_pkt_send(ssh, s->pktout);
9053 crWaitUntilV(pktin);
9054 if (pktin->type == SSH2_MSG_SERVICE_ACCEPT)
9055 s->done_service_req = TRUE;
9057 if (!s->done_service_req) {
9059 * Request connection protocol directly, without authentication.
9061 s->pktout = ssh2_pkt_init(SSH2_MSG_SERVICE_REQUEST);
9062 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9063 ssh2_pkt_send(ssh, s->pktout);
9064 crWaitUntilV(pktin);
9065 if (pktin->type == SSH2_MSG_SERVICE_ACCEPT) {
9066 s->we_are_in = TRUE; /* no auth required */
9068 bombout(("Server refused service request"));
9073 s->we_are_in = TRUE;
9076 /* Arrange to be able to deal with any BANNERs that come in.
9077 * (We do this now as packets may come in during the next bit.) */
9078 bufchain_init(&ssh->banner);
9079 ssh->packet_dispatch[SSH2_MSG_USERAUTH_BANNER] =
9080 ssh2_msg_userauth_banner;
9083 * Misc one-time setup for authentication.
9085 s->publickey_blob = NULL;
9086 if (!s->we_are_in) {
9089 * Load the public half of any configured public key file
9092 s->keyfile = conf_get_filename(ssh->conf, CONF_keyfile);
9093 if (!filename_is_null(s->keyfile)) {
9095 logeventf(ssh, "Reading key file \"%.150s\"",
9096 filename_to_str(s->keyfile));
9097 keytype = key_type(s->keyfile);
9098 if (keytype == SSH_KEYTYPE_SSH2 ||
9099 keytype == SSH_KEYTYPE_SSH2_PUBLIC_RFC4716 ||
9100 keytype == SSH_KEYTYPE_SSH2_PUBLIC_OPENSSH) {
9103 ssh2_userkey_loadpub(s->keyfile,
9104 &s->publickey_algorithm,
9105 &s->publickey_bloblen,
9106 &s->publickey_comment, &error);
9107 if (s->publickey_blob) {
9108 s->privatekey_available = (keytype == SSH_KEYTYPE_SSH2);
9109 if (!s->privatekey_available)
9110 logeventf(ssh, "Key file contains public key only");
9111 s->privatekey_encrypted =
9112 ssh2_userkey_encrypted(s->keyfile, NULL);
9115 logeventf(ssh, "Unable to load key (%s)",
9117 msgbuf = dupprintf("Unable to load key file "
9118 "\"%.150s\" (%s)\r\n",
9119 filename_to_str(s->keyfile),
9121 c_write_str(ssh, msgbuf);
9126 logeventf(ssh, "Unable to use this key file (%s)",
9127 key_type_to_str(keytype));
9128 msgbuf = dupprintf("Unable to use key file \"%.150s\""
9130 filename_to_str(s->keyfile),
9131 key_type_to_str(keytype));
9132 c_write_str(ssh, msgbuf);
9134 s->publickey_blob = NULL;
9139 * Find out about any keys Pageant has (but if there's a
9140 * public key configured, filter out all others).
9143 s->agent_response = NULL;
9144 s->pkblob_in_agent = NULL;
9145 if (conf_get_int(ssh->conf, CONF_tryagent) && agent_exists()) {
9149 logevent("Pageant is running. Requesting keys.");
9151 /* Request the keys held by the agent. */
9152 PUT_32BIT(s->agent_request, 1);
9153 s->agent_request[4] = SSH2_AGENTC_REQUEST_IDENTITIES;
9154 if (!agent_query(s->agent_request, 5, &r, &s->agent_responselen,
9155 ssh_agent_callback, ssh)) {
9159 bombout(("Unexpected data from server while"
9160 " waiting for agent response"));
9163 } while (pktin || inlen > 0);
9164 r = ssh->agent_response;
9165 s->agent_responselen = ssh->agent_response_len;
9167 s->agent_response = (unsigned char *) r;
9168 if (s->agent_response && s->agent_responselen >= 5 &&
9169 s->agent_response[4] == SSH2_AGENT_IDENTITIES_ANSWER) {
9172 p = s->agent_response + 5;
9173 s->nkeys = toint(GET_32BIT(p));
9176 * Vet the Pageant response to ensure that the key
9177 * count and blob lengths make sense.
9180 logeventf(ssh, "Pageant response contained a negative"
9181 " key count %d", s->nkeys);
9183 goto done_agent_query;
9185 unsigned char *q = p + 4;
9186 int lenleft = s->agent_responselen - 5 - 4;
9188 for (keyi = 0; keyi < s->nkeys; keyi++) {
9189 int bloblen, commentlen;
9191 logeventf(ssh, "Pageant response was truncated");
9193 goto done_agent_query;
9195 bloblen = toint(GET_32BIT(q));
9196 if (bloblen < 0 || bloblen > lenleft) {
9197 logeventf(ssh, "Pageant response was truncated");
9199 goto done_agent_query;
9201 lenleft -= 4 + bloblen;
9203 commentlen = toint(GET_32BIT(q));
9204 if (commentlen < 0 || commentlen > lenleft) {
9205 logeventf(ssh, "Pageant response was truncated");
9207 goto done_agent_query;
9209 lenleft -= 4 + commentlen;
9210 q += 4 + commentlen;
9215 logeventf(ssh, "Pageant has %d SSH-2 keys", s->nkeys);
9216 if (s->publickey_blob) {
9217 /* See if configured key is in agent. */
9218 for (keyi = 0; keyi < s->nkeys; keyi++) {
9219 s->pklen = toint(GET_32BIT(p));
9220 if (s->pklen == s->publickey_bloblen &&
9221 !memcmp(p+4, s->publickey_blob,
9222 s->publickey_bloblen)) {
9223 logeventf(ssh, "Pageant key #%d matches "
9224 "configured key file", keyi);
9226 s->pkblob_in_agent = p;
9230 p += toint(GET_32BIT(p)) + 4; /* comment */
9232 if (!s->pkblob_in_agent) {
9233 logevent("Configured key file not in Pageant");
9238 logevent("Failed to get reply from Pageant");
9246 * We repeat this whole loop, including the username prompt,
9247 * until we manage a successful authentication. If the user
9248 * types the wrong _password_, they can be sent back to the
9249 * beginning to try another username, if this is configured on.
9250 * (If they specify a username in the config, they are never
9251 * asked, even if they do give a wrong password.)
9253 * I think this best serves the needs of
9255 * - the people who have no configuration, no keys, and just
9256 * want to try repeated (username,password) pairs until they
9257 * type both correctly
9259 * - people who have keys and configuration but occasionally
9260 * need to fall back to passwords
9262 * - people with a key held in Pageant, who might not have
9263 * logged in to a particular machine before; so they want to
9264 * type a username, and then _either_ their key will be
9265 * accepted, _or_ they will type a password. If they mistype
9266 * the username they will want to be able to get back and
9269 s->got_username = FALSE;
9270 while (!s->we_are_in) {
9274 if (s->got_username && !conf_get_int(ssh->conf, CONF_change_username)) {
9276 * We got a username last time round this loop, and
9277 * with change_username turned off we don't try to get
9280 } else if ((ssh->username = get_remote_username(ssh->conf)) == NULL) {
9281 int ret; /* need not be kept over crReturn */
9282 s->cur_prompt = new_prompts(ssh->frontend);
9283 s->cur_prompt->to_server = TRUE;
9284 s->cur_prompt->name = dupstr("SSH login name");
9285 add_prompt(s->cur_prompt, dupstr("login as: "), TRUE);
9286 ret = get_userpass_input(s->cur_prompt, NULL, 0);
9289 crWaitUntilV(!pktin);
9290 ret = get_userpass_input(s->cur_prompt, in, inlen);
9295 * get_userpass_input() failed to get a username.
9298 free_prompts(s->cur_prompt);
9299 ssh_disconnect(ssh, "No username provided", NULL, 0, TRUE);
9302 ssh->username = dupstr(s->cur_prompt->prompts[0]->result);
9303 free_prompts(s->cur_prompt);
9306 if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
9307 stuff = dupprintf("Using username \"%s\".\r\n", ssh->username);
9308 c_write_str(ssh, stuff);
9312 s->got_username = TRUE;
9315 * Send an authentication request using method "none": (a)
9316 * just in case it succeeds, and (b) so that we know what
9317 * authentication methods we can usefully try next.
9319 ssh->pkt_actx = SSH2_PKTCTX_NOAUTH;
9321 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9322 ssh2_pkt_addstring(s->pktout, ssh->username);
9323 ssh2_pkt_addstring(s->pktout, "ssh-connection");/* service requested */
9324 ssh2_pkt_addstring(s->pktout, "none"); /* method */
9325 ssh2_pkt_send(ssh, s->pktout);
9326 s->type = AUTH_TYPE_NONE;
9328 s->we_are_in = FALSE;
9330 s->tried_pubkey_config = FALSE;
9331 s->kbd_inter_refused = FALSE;
9333 /* Reset agent request state. */
9334 s->done_agent = FALSE;
9335 if (s->agent_response) {
9336 if (s->pkblob_in_agent) {
9337 s->agentp = s->pkblob_in_agent;
9339 s->agentp = s->agent_response + 5 + 4;
9345 char *methods = NULL;
9349 * Wait for the result of the last authentication request.
9352 crWaitUntilV(pktin);
9354 * Now is a convenient point to spew any banner material
9355 * that we've accumulated. (This should ensure that when
9356 * we exit the auth loop, we haven't any left to deal
9360 int size = bufchain_size(&ssh->banner);
9362 * Don't show the banner if we're operating in
9363 * non-verbose non-interactive mode. (It's probably
9364 * a script, which means nobody will read the
9365 * banner _anyway_, and moreover the printing of
9366 * the banner will screw up processing on the
9367 * output of (say) plink.)
9369 if (size && (flags & (FLAG_VERBOSE | FLAG_INTERACTIVE))) {
9370 char *banner = snewn(size, char);
9371 bufchain_fetch(&ssh->banner, banner, size);
9372 c_write_untrusted(ssh, banner, size);
9375 bufchain_clear(&ssh->banner);
9377 if (pktin->type == SSH2_MSG_USERAUTH_SUCCESS) {
9378 logevent("Access granted");
9379 s->we_are_in = s->userauth_success = TRUE;
9383 if (pktin->type != SSH2_MSG_USERAUTH_FAILURE && s->type != AUTH_TYPE_GSSAPI) {
9384 bombout(("Strange packet received during authentication: "
9385 "type %d", pktin->type));
9392 * OK, we're now sitting on a USERAUTH_FAILURE message, so
9393 * we can look at the string in it and know what we can
9394 * helpfully try next.
9396 if (pktin->type == SSH2_MSG_USERAUTH_FAILURE) {
9397 ssh_pkt_getstring(pktin, &methods, &methlen);
9398 if (!ssh2_pkt_getbool(pktin)) {
9400 * We have received an unequivocal Access
9401 * Denied. This can translate to a variety of
9402 * messages, or no message at all.
9404 * For forms of authentication which are attempted
9405 * implicitly, by which I mean without printing
9406 * anything in the window indicating that we're
9407 * trying them, we should never print 'Access
9410 * If we do print a message saying that we're
9411 * attempting some kind of authentication, it's OK
9412 * to print a followup message saying it failed -
9413 * but the message may sometimes be more specific
9414 * than simply 'Access denied'.
9416 * Additionally, if we'd just tried password
9417 * authentication, we should break out of this
9418 * whole loop so as to go back to the username
9419 * prompt (iff we're configured to allow
9420 * username change attempts).
9422 if (s->type == AUTH_TYPE_NONE) {
9424 } else if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD ||
9425 s->type == AUTH_TYPE_PUBLICKEY_OFFER_QUIET) {
9426 if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD)
9427 c_write_str(ssh, "Server refused our key\r\n");
9428 logevent("Server refused our key");
9429 } else if (s->type == AUTH_TYPE_PUBLICKEY) {
9430 /* This _shouldn't_ happen except by a
9431 * protocol bug causing client and server to
9432 * disagree on what is a correct signature. */
9433 c_write_str(ssh, "Server refused public-key signature"
9434 " despite accepting key!\r\n");
9435 logevent("Server refused public-key signature"
9436 " despite accepting key!");
9437 } else if (s->type==AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET) {
9438 /* quiet, so no c_write */
9439 logevent("Server refused keyboard-interactive authentication");
9440 } else if (s->type==AUTH_TYPE_GSSAPI) {
9441 /* always quiet, so no c_write */
9442 /* also, the code down in the GSSAPI block has
9443 * already logged this in the Event Log */
9444 } else if (s->type == AUTH_TYPE_KEYBOARD_INTERACTIVE) {
9445 logevent("Keyboard-interactive authentication failed");
9446 c_write_str(ssh, "Access denied\r\n");
9448 assert(s->type == AUTH_TYPE_PASSWORD);
9449 logevent("Password authentication failed");
9450 c_write_str(ssh, "Access denied\r\n");
9452 if (conf_get_int(ssh->conf, CONF_change_username)) {
9453 /* XXX perhaps we should allow
9454 * keyboard-interactive to do this too? */
9455 s->we_are_in = FALSE;
9460 c_write_str(ssh, "Further authentication required\r\n");
9461 logevent("Further authentication required");
9465 in_commasep_string("publickey", methods, methlen);
9467 in_commasep_string("password", methods, methlen);
9468 s->can_keyb_inter = conf_get_int(ssh->conf, CONF_try_ki_auth) &&
9469 in_commasep_string("keyboard-interactive", methods, methlen);
9471 if (conf_get_int(ssh->conf, CONF_try_gssapi_auth) &&
9472 in_commasep_string("gssapi-with-mic", methods, methlen)) {
9473 /* Try loading the GSS libraries and see if we
9476 ssh->gsslibs = ssh_gss_setup(ssh->conf);
9477 s->can_gssapi = (ssh->gsslibs->nlibraries > 0);
9479 /* No point in even bothering to try to load the
9480 * GSS libraries, if the user configuration and
9481 * server aren't both prepared to attempt GSSAPI
9482 * auth in the first place. */
9483 s->can_gssapi = FALSE;
9488 ssh->pkt_actx = SSH2_PKTCTX_NOAUTH;
9490 if (s->can_pubkey && !s->done_agent && s->nkeys) {
9493 * Attempt public-key authentication using a key from Pageant.
9496 ssh->pkt_actx = SSH2_PKTCTX_PUBLICKEY;
9498 logeventf(ssh, "Trying Pageant key #%d", s->keyi);
9500 /* Unpack key from agent response */
9501 s->pklen = toint(GET_32BIT(s->agentp));
9503 s->pkblob = (char *)s->agentp;
9504 s->agentp += s->pklen;
9505 s->alglen = toint(GET_32BIT(s->pkblob));
9506 s->alg = s->pkblob + 4;
9507 s->commentlen = toint(GET_32BIT(s->agentp));
9509 s->commentp = (char *)s->agentp;
9510 s->agentp += s->commentlen;
9511 /* s->agentp now points at next key, if any */
9513 /* See if server will accept it */
9514 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9515 ssh2_pkt_addstring(s->pktout, ssh->username);
9516 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9517 /* service requested */
9518 ssh2_pkt_addstring(s->pktout, "publickey");
9520 ssh2_pkt_addbool(s->pktout, FALSE); /* no signature included */
9521 ssh2_pkt_addstring_start(s->pktout);
9522 ssh2_pkt_addstring_data(s->pktout, s->alg, s->alglen);
9523 ssh2_pkt_addstring_start(s->pktout);
9524 ssh2_pkt_addstring_data(s->pktout, s->pkblob, s->pklen);
9525 ssh2_pkt_send(ssh, s->pktout);
9526 s->type = AUTH_TYPE_PUBLICKEY_OFFER_QUIET;
9528 crWaitUntilV(pktin);
9529 if (pktin->type != SSH2_MSG_USERAUTH_PK_OK) {
9531 /* Offer of key refused. */
9538 if (flags & FLAG_VERBOSE) {
9539 c_write_str(ssh, "Authenticating with "
9541 c_write(ssh, s->commentp, s->commentlen);
9542 c_write_str(ssh, "\" from agent\r\n");
9546 * Server is willing to accept the key.
9547 * Construct a SIGN_REQUEST.
9549 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9550 ssh2_pkt_addstring(s->pktout, ssh->username);
9551 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9552 /* service requested */
9553 ssh2_pkt_addstring(s->pktout, "publickey");
9555 ssh2_pkt_addbool(s->pktout, TRUE); /* signature included */
9556 ssh2_pkt_addstring_start(s->pktout);
9557 ssh2_pkt_addstring_data(s->pktout, s->alg, s->alglen);
9558 ssh2_pkt_addstring_start(s->pktout);
9559 ssh2_pkt_addstring_data(s->pktout, s->pkblob, s->pklen);
9561 /* Ask agent for signature. */
9562 s->siglen = s->pktout->length - 5 + 4 +
9563 ssh->v2_session_id_len;
9564 if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
9566 s->len = 1; /* message type */
9567 s->len += 4 + s->pklen; /* key blob */
9568 s->len += 4 + s->siglen; /* data to sign */
9569 s->len += 4; /* flags */
9570 s->agentreq = snewn(4 + s->len, char);
9571 PUT_32BIT(s->agentreq, s->len);
9572 s->q = s->agentreq + 4;
9573 *s->q++ = SSH2_AGENTC_SIGN_REQUEST;
9574 PUT_32BIT(s->q, s->pklen);
9576 memcpy(s->q, s->pkblob, s->pklen);
9578 PUT_32BIT(s->q, s->siglen);
9580 /* Now the data to be signed... */
9581 if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
9582 PUT_32BIT(s->q, ssh->v2_session_id_len);
9585 memcpy(s->q, ssh->v2_session_id,
9586 ssh->v2_session_id_len);
9587 s->q += ssh->v2_session_id_len;
9588 memcpy(s->q, s->pktout->data + 5,
9589 s->pktout->length - 5);
9590 s->q += s->pktout->length - 5;
9591 /* And finally the (zero) flags word. */
9593 if (!agent_query(s->agentreq, s->len + 4,
9595 ssh_agent_callback, ssh)) {
9599 bombout(("Unexpected data from server"
9600 " while waiting for agent"
9604 } while (pktin || inlen > 0);
9605 vret = ssh->agent_response;
9606 s->retlen = ssh->agent_response_len;
9611 if (s->retlen >= 9 &&
9612 s->ret[4] == SSH2_AGENT_SIGN_RESPONSE &&
9613 GET_32BIT(s->ret + 5) <= (unsigned)(s->retlen-9)) {
9614 logevent("Sending Pageant's response");
9615 ssh2_add_sigblob(ssh, s->pktout,
9616 s->pkblob, s->pklen,
9618 GET_32BIT(s->ret + 5));
9619 ssh2_pkt_send(ssh, s->pktout);
9620 s->type = AUTH_TYPE_PUBLICKEY;
9622 /* FIXME: less drastic response */
9623 bombout(("Pageant failed to answer challenge"));
9629 /* Do we have any keys left to try? */
9630 if (s->pkblob_in_agent) {
9631 s->done_agent = TRUE;
9632 s->tried_pubkey_config = TRUE;
9635 if (s->keyi >= s->nkeys)
9636 s->done_agent = TRUE;
9639 } else if (s->can_pubkey && s->publickey_blob &&
9640 s->privatekey_available && !s->tried_pubkey_config) {
9642 struct ssh2_userkey *key; /* not live over crReturn */
9643 char *passphrase; /* not live over crReturn */
9645 ssh->pkt_actx = SSH2_PKTCTX_PUBLICKEY;
9647 s->tried_pubkey_config = TRUE;
9650 * Try the public key supplied in the configuration.
9652 * First, offer the public blob to see if the server is
9653 * willing to accept it.
9655 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9656 ssh2_pkt_addstring(s->pktout, ssh->username);
9657 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9658 /* service requested */
9659 ssh2_pkt_addstring(s->pktout, "publickey"); /* method */
9660 ssh2_pkt_addbool(s->pktout, FALSE);
9661 /* no signature included */
9662 ssh2_pkt_addstring(s->pktout, s->publickey_algorithm);
9663 ssh2_pkt_addstring_start(s->pktout);
9664 ssh2_pkt_addstring_data(s->pktout,
9665 (char *)s->publickey_blob,
9666 s->publickey_bloblen);
9667 ssh2_pkt_send(ssh, s->pktout);
9668 logevent("Offered public key");
9670 crWaitUntilV(pktin);
9671 if (pktin->type != SSH2_MSG_USERAUTH_PK_OK) {
9672 /* Key refused. Give up. */
9673 s->gotit = TRUE; /* reconsider message next loop */
9674 s->type = AUTH_TYPE_PUBLICKEY_OFFER_LOUD;
9675 continue; /* process this new message */
9677 logevent("Offer of public key accepted");
9680 * Actually attempt a serious authentication using
9683 if (flags & FLAG_VERBOSE) {
9684 c_write_str(ssh, "Authenticating with public key \"");
9685 c_write_str(ssh, s->publickey_comment);
9686 c_write_str(ssh, "\"\r\n");
9690 const char *error; /* not live over crReturn */
9691 if (s->privatekey_encrypted) {
9693 * Get a passphrase from the user.
9695 int ret; /* need not be kept over crReturn */
9696 s->cur_prompt = new_prompts(ssh->frontend);
9697 s->cur_prompt->to_server = FALSE;
9698 s->cur_prompt->name = dupstr("SSH key passphrase");
9699 add_prompt(s->cur_prompt,
9700 dupprintf("Passphrase for key \"%.100s\": ",
9701 s->publickey_comment),
9703 ret = get_userpass_input(s->cur_prompt, NULL, 0);
9706 crWaitUntilV(!pktin);
9707 ret = get_userpass_input(s->cur_prompt,
9712 /* Failed to get a passphrase. Terminate. */
9713 free_prompts(s->cur_prompt);
9714 ssh_disconnect(ssh, NULL,
9715 "Unable to authenticate",
9716 SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER,
9721 dupstr(s->cur_prompt->prompts[0]->result);
9722 free_prompts(s->cur_prompt);
9724 passphrase = NULL; /* no passphrase needed */
9728 * Try decrypting the key.
9730 s->keyfile = conf_get_filename(ssh->conf, CONF_keyfile);
9731 key = ssh2_load_userkey(s->keyfile, passphrase, &error);
9733 /* burn the evidence */
9734 smemclr(passphrase, strlen(passphrase));
9737 if (key == SSH2_WRONG_PASSPHRASE || key == NULL) {
9739 (key == SSH2_WRONG_PASSPHRASE)) {
9740 c_write_str(ssh, "Wrong passphrase\r\n");
9742 /* and loop again */
9744 c_write_str(ssh, "Unable to load private key (");
9745 c_write_str(ssh, error);
9746 c_write_str(ssh, ")\r\n");
9748 break; /* try something else */
9754 unsigned char *pkblob, *sigblob, *sigdata;
9755 int pkblob_len, sigblob_len, sigdata_len;
9759 * We have loaded the private key and the server
9760 * has announced that it's willing to accept it.
9761 * Hallelujah. Generate a signature and send it.
9763 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9764 ssh2_pkt_addstring(s->pktout, ssh->username);
9765 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9766 /* service requested */
9767 ssh2_pkt_addstring(s->pktout, "publickey");
9769 ssh2_pkt_addbool(s->pktout, TRUE);
9770 /* signature follows */
9771 ssh2_pkt_addstring(s->pktout, key->alg->name);
9772 pkblob = key->alg->public_blob(key->data,
9774 ssh2_pkt_addstring_start(s->pktout);
9775 ssh2_pkt_addstring_data(s->pktout, (char *)pkblob,
9779 * The data to be signed is:
9783 * followed by everything so far placed in the
9786 sigdata_len = s->pktout->length - 5 + 4 +
9787 ssh->v2_session_id_len;
9788 if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
9790 sigdata = snewn(sigdata_len, unsigned char);
9792 if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
9793 PUT_32BIT(sigdata+p, ssh->v2_session_id_len);
9796 memcpy(sigdata+p, ssh->v2_session_id,
9797 ssh->v2_session_id_len);
9798 p += ssh->v2_session_id_len;
9799 memcpy(sigdata+p, s->pktout->data + 5,
9800 s->pktout->length - 5);
9801 p += s->pktout->length - 5;
9802 assert(p == sigdata_len);
9803 sigblob = key->alg->sign(key->data, (char *)sigdata,
9804 sigdata_len, &sigblob_len);
9805 ssh2_add_sigblob(ssh, s->pktout, pkblob, pkblob_len,
9806 sigblob, sigblob_len);
9811 ssh2_pkt_send(ssh, s->pktout);
9812 logevent("Sent public key signature");
9813 s->type = AUTH_TYPE_PUBLICKEY;
9814 key->alg->freekey(key->data);
9815 sfree(key->comment);
9820 } else if (s->can_gssapi && !s->tried_gssapi) {
9822 /* GSSAPI Authentication */
9827 s->type = AUTH_TYPE_GSSAPI;
9828 s->tried_gssapi = TRUE;
9830 ssh->pkt_actx = SSH2_PKTCTX_GSSAPI;
9833 * Pick the highest GSS library on the preference
9839 for (i = 0; i < ngsslibs; i++) {
9840 int want_id = conf_get_int_int(ssh->conf,
9841 CONF_ssh_gsslist, i);
9842 for (j = 0; j < ssh->gsslibs->nlibraries; j++)
9843 if (ssh->gsslibs->libraries[j].id == want_id) {
9844 s->gsslib = &ssh->gsslibs->libraries[j];
9845 goto got_gsslib; /* double break */
9850 * We always expect to have found something in
9851 * the above loop: we only came here if there
9852 * was at least one viable GSS library, and the
9853 * preference list should always mention
9854 * everything and only change the order.
9859 if (s->gsslib->gsslogmsg)
9860 logevent(s->gsslib->gsslogmsg);
9862 /* Sending USERAUTH_REQUEST with "gssapi-with-mic" method */
9863 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9864 ssh2_pkt_addstring(s->pktout, ssh->username);
9865 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9866 ssh2_pkt_addstring(s->pktout, "gssapi-with-mic");
9867 logevent("Attempting GSSAPI authentication");
9869 /* add mechanism info */
9870 s->gsslib->indicate_mech(s->gsslib, &s->gss_buf);
9872 /* number of GSSAPI mechanisms */
9873 ssh2_pkt_adduint32(s->pktout,1);
9875 /* length of OID + 2 */
9876 ssh2_pkt_adduint32(s->pktout, s->gss_buf.length + 2);
9877 ssh2_pkt_addbyte(s->pktout, SSH2_GSS_OIDTYPE);
9880 ssh2_pkt_addbyte(s->pktout, (unsigned char) s->gss_buf.length);
9882 ssh_pkt_adddata(s->pktout, s->gss_buf.value,
9884 ssh2_pkt_send(ssh, s->pktout);
9885 crWaitUntilV(pktin);
9886 if (pktin->type != SSH2_MSG_USERAUTH_GSSAPI_RESPONSE) {
9887 logevent("GSSAPI authentication request refused");
9891 /* check returned packet ... */
9893 ssh_pkt_getstring(pktin, &data, &len);
9894 s->gss_rcvtok.value = data;
9895 s->gss_rcvtok.length = len;
9896 if (s->gss_rcvtok.length != s->gss_buf.length + 2 ||
9897 ((char *)s->gss_rcvtok.value)[0] != SSH2_GSS_OIDTYPE ||
9898 ((char *)s->gss_rcvtok.value)[1] != s->gss_buf.length ||
9899 memcmp((char *)s->gss_rcvtok.value + 2,
9900 s->gss_buf.value,s->gss_buf.length) ) {
9901 logevent("GSSAPI authentication - wrong response from server");
9905 /* now start running */
9906 s->gss_stat = s->gsslib->import_name(s->gsslib,
9909 if (s->gss_stat != SSH_GSS_OK) {
9910 if (s->gss_stat == SSH_GSS_BAD_HOST_NAME)
9911 logevent("GSSAPI import name failed - Bad service name");
9913 logevent("GSSAPI import name failed");
9917 /* fetch TGT into GSS engine */
9918 s->gss_stat = s->gsslib->acquire_cred(s->gsslib, &s->gss_ctx);
9920 if (s->gss_stat != SSH_GSS_OK) {
9921 logevent("GSSAPI authentication failed to get credentials");
9922 s->gsslib->release_name(s->gsslib, &s->gss_srv_name);
9926 /* initial tokens are empty */
9927 SSH_GSS_CLEAR_BUF(&s->gss_rcvtok);
9928 SSH_GSS_CLEAR_BUF(&s->gss_sndtok);
9930 /* now enter the loop */
9932 s->gss_stat = s->gsslib->init_sec_context
9936 conf_get_int(ssh->conf, CONF_gssapifwd),
9940 if (s->gss_stat!=SSH_GSS_S_COMPLETE &&
9941 s->gss_stat!=SSH_GSS_S_CONTINUE_NEEDED) {
9942 logevent("GSSAPI authentication initialisation failed");
9944 if (s->gsslib->display_status(s->gsslib, s->gss_ctx,
9945 &s->gss_buf) == SSH_GSS_OK) {
9946 logevent(s->gss_buf.value);
9947 sfree(s->gss_buf.value);
9952 logevent("GSSAPI authentication initialised");
9954 /* Client and server now exchange tokens until GSSAPI
9955 * no longer says CONTINUE_NEEDED */
9957 if (s->gss_sndtok.length != 0) {
9958 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
9959 ssh_pkt_addstring_start(s->pktout);
9960 ssh_pkt_addstring_data(s->pktout,s->gss_sndtok.value,s->gss_sndtok.length);
9961 ssh2_pkt_send(ssh, s->pktout);
9962 s->gsslib->free_tok(s->gsslib, &s->gss_sndtok);
9965 if (s->gss_stat == SSH_GSS_S_CONTINUE_NEEDED) {
9966 crWaitUntilV(pktin);
9967 if (pktin->type != SSH2_MSG_USERAUTH_GSSAPI_TOKEN) {
9968 logevent("GSSAPI authentication - bad server response");
9969 s->gss_stat = SSH_GSS_FAILURE;
9972 ssh_pkt_getstring(pktin, &data, &len);
9973 s->gss_rcvtok.value = data;
9974 s->gss_rcvtok.length = len;
9976 } while (s-> gss_stat == SSH_GSS_S_CONTINUE_NEEDED);
9978 if (s->gss_stat != SSH_GSS_OK) {
9979 s->gsslib->release_name(s->gsslib, &s->gss_srv_name);
9980 s->gsslib->release_cred(s->gsslib, &s->gss_ctx);
9983 logevent("GSSAPI authentication loop finished OK");
9985 /* Now send the MIC */
9987 s->pktout = ssh2_pkt_init(0);
9988 micoffset = s->pktout->length;
9989 ssh_pkt_addstring_start(s->pktout);
9990 ssh_pkt_addstring_data(s->pktout, (char *)ssh->v2_session_id, ssh->v2_session_id_len);
9991 ssh_pkt_addbyte(s->pktout, SSH2_MSG_USERAUTH_REQUEST);
9992 ssh_pkt_addstring(s->pktout, ssh->username);
9993 ssh_pkt_addstring(s->pktout, "ssh-connection");
9994 ssh_pkt_addstring(s->pktout, "gssapi-with-mic");
9996 s->gss_buf.value = (char *)s->pktout->data + micoffset;
9997 s->gss_buf.length = s->pktout->length - micoffset;
9999 s->gsslib->get_mic(s->gsslib, s->gss_ctx, &s->gss_buf, &mic);
10000 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_GSSAPI_MIC);
10001 ssh_pkt_addstring_start(s->pktout);
10002 ssh_pkt_addstring_data(s->pktout, mic.value, mic.length);
10003 ssh2_pkt_send(ssh, s->pktout);
10004 s->gsslib->free_mic(s->gsslib, &mic);
10008 s->gsslib->release_name(s->gsslib, &s->gss_srv_name);
10009 s->gsslib->release_cred(s->gsslib, &s->gss_ctx);
10012 } else if (s->can_keyb_inter && !s->kbd_inter_refused) {
10015 * Keyboard-interactive authentication.
10018 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
10020 ssh->pkt_actx = SSH2_PKTCTX_KBDINTER;
10022 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
10023 ssh2_pkt_addstring(s->pktout, ssh->username);
10024 ssh2_pkt_addstring(s->pktout, "ssh-connection");
10025 /* service requested */
10026 ssh2_pkt_addstring(s->pktout, "keyboard-interactive");
10028 ssh2_pkt_addstring(s->pktout, ""); /* lang */
10029 ssh2_pkt_addstring(s->pktout, ""); /* submethods */
10030 ssh2_pkt_send(ssh, s->pktout);
10032 logevent("Attempting keyboard-interactive authentication");
10034 crWaitUntilV(pktin);
10035 if (pktin->type != SSH2_MSG_USERAUTH_INFO_REQUEST) {
10036 /* Server is not willing to do keyboard-interactive
10037 * at all (or, bizarrely but legally, accepts the
10038 * user without actually issuing any prompts).
10039 * Give up on it entirely. */
10041 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET;
10042 s->kbd_inter_refused = TRUE; /* don't try it again */
10047 * Loop while the server continues to send INFO_REQUESTs.
10049 while (pktin->type == SSH2_MSG_USERAUTH_INFO_REQUEST) {
10051 char *name, *inst, *lang;
10052 int name_len, inst_len, lang_len;
10056 * We've got a fresh USERAUTH_INFO_REQUEST.
10057 * Get the preamble and start building a prompt.
10059 ssh_pkt_getstring(pktin, &name, &name_len);
10060 ssh_pkt_getstring(pktin, &inst, &inst_len);
10061 ssh_pkt_getstring(pktin, &lang, &lang_len);
10062 s->cur_prompt = new_prompts(ssh->frontend);
10063 s->cur_prompt->to_server = TRUE;
10066 * Get any prompt(s) from the packet.
10068 s->num_prompts = ssh_pkt_getuint32(pktin);
10069 for (i = 0; i < s->num_prompts; i++) {
10073 static char noprompt[] =
10074 "<server failed to send prompt>: ";
10076 ssh_pkt_getstring(pktin, &prompt, &prompt_len);
10077 echo = ssh2_pkt_getbool(pktin);
10080 prompt_len = lenof(noprompt)-1;
10082 add_prompt(s->cur_prompt,
10083 dupprintf("%.*s", prompt_len, prompt),
10088 /* FIXME: better prefix to distinguish from
10089 * local prompts? */
10090 s->cur_prompt->name =
10091 dupprintf("SSH server: %.*s", name_len, name);
10092 s->cur_prompt->name_reqd = TRUE;
10094 s->cur_prompt->name =
10095 dupstr("SSH server authentication");
10096 s->cur_prompt->name_reqd = FALSE;
10098 /* We add a prefix to try to make it clear that a prompt
10099 * has come from the server.
10100 * FIXME: ugly to print "Using..." in prompt _every_
10101 * time round. Can this be done more subtly? */
10102 /* Special case: for reasons best known to themselves,
10103 * some servers send k-i requests with no prompts and
10104 * nothing to display. Keep quiet in this case. */
10105 if (s->num_prompts || name_len || inst_len) {
10106 s->cur_prompt->instruction =
10107 dupprintf("Using keyboard-interactive authentication.%s%.*s",
10108 inst_len ? "\n" : "", inst_len, inst);
10109 s->cur_prompt->instr_reqd = TRUE;
10111 s->cur_prompt->instr_reqd = FALSE;
10115 * Display any instructions, and get the user's
10119 int ret; /* not live over crReturn */
10120 ret = get_userpass_input(s->cur_prompt, NULL, 0);
10123 crWaitUntilV(!pktin);
10124 ret = get_userpass_input(s->cur_prompt, in, inlen);
10129 * Failed to get responses. Terminate.
10131 free_prompts(s->cur_prompt);
10132 ssh_disconnect(ssh, NULL, "Unable to authenticate",
10133 SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER,
10140 * Send the response(s) to the server.
10142 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_INFO_RESPONSE);
10143 ssh2_pkt_adduint32(s->pktout, s->num_prompts);
10144 for (i=0; i < s->num_prompts; i++) {
10145 ssh2_pkt_addstring(s->pktout,
10146 s->cur_prompt->prompts[i]->result);
10148 ssh2_pkt_send_with_padding(ssh, s->pktout, 256);
10151 * Free the prompts structure from this iteration.
10152 * If there's another, a new one will be allocated
10153 * when we return to the top of this while loop.
10155 free_prompts(s->cur_prompt);
10158 * Get the next packet in case it's another
10161 crWaitUntilV(pktin);
10166 * We should have SUCCESS or FAILURE now.
10170 } else if (s->can_passwd) {
10173 * Plain old password authentication.
10175 int ret; /* not live over crReturn */
10176 int changereq_first_time; /* not live over crReturn */
10178 ssh->pkt_actx = SSH2_PKTCTX_PASSWORD;
10180 s->cur_prompt = new_prompts(ssh->frontend);
10181 s->cur_prompt->to_server = TRUE;
10182 s->cur_prompt->name = dupstr("SSH password");
10183 add_prompt(s->cur_prompt, dupprintf("%s@%s's password: ",
10188 ret = get_userpass_input(s->cur_prompt, NULL, 0);
10191 crWaitUntilV(!pktin);
10192 ret = get_userpass_input(s->cur_prompt, in, inlen);
10197 * Failed to get responses. Terminate.
10199 free_prompts(s->cur_prompt);
10200 ssh_disconnect(ssh, NULL, "Unable to authenticate",
10201 SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER,
10206 * Squirrel away the password. (We may need it later if
10207 * asked to change it.)
10209 s->password = dupstr(s->cur_prompt->prompts[0]->result);
10210 free_prompts(s->cur_prompt);
10213 * Send the password packet.
10215 * We pad out the password packet to 256 bytes to make
10216 * it harder for an attacker to find the length of the
10219 * Anyone using a password longer than 256 bytes
10220 * probably doesn't have much to worry about from
10221 * people who find out how long their password is!
10223 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
10224 ssh2_pkt_addstring(s->pktout, ssh->username);
10225 ssh2_pkt_addstring(s->pktout, "ssh-connection");
10226 /* service requested */
10227 ssh2_pkt_addstring(s->pktout, "password");
10228 ssh2_pkt_addbool(s->pktout, FALSE);
10229 ssh2_pkt_addstring(s->pktout, s->password);
10230 ssh2_pkt_send_with_padding(ssh, s->pktout, 256);
10231 logevent("Sent password");
10232 s->type = AUTH_TYPE_PASSWORD;
10235 * Wait for next packet, in case it's a password change
10238 crWaitUntilV(pktin);
10239 changereq_first_time = TRUE;
10241 while (pktin->type == SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ) {
10244 * We're being asked for a new password
10245 * (perhaps not for the first time).
10246 * Loop until the server accepts it.
10249 int got_new = FALSE; /* not live over crReturn */
10250 char *prompt; /* not live over crReturn */
10251 int prompt_len; /* not live over crReturn */
10255 if (changereq_first_time)
10256 msg = "Server requested password change";
10258 msg = "Server rejected new password";
10260 c_write_str(ssh, msg);
10261 c_write_str(ssh, "\r\n");
10264 ssh_pkt_getstring(pktin, &prompt, &prompt_len);
10266 s->cur_prompt = new_prompts(ssh->frontend);
10267 s->cur_prompt->to_server = TRUE;
10268 s->cur_prompt->name = dupstr("New SSH password");
10269 s->cur_prompt->instruction =
10270 dupprintf("%.*s", prompt_len, prompt);
10271 s->cur_prompt->instr_reqd = TRUE;
10273 * There's no explicit requirement in the protocol
10274 * for the "old" passwords in the original and
10275 * password-change messages to be the same, and
10276 * apparently some Cisco kit supports password change
10277 * by the user entering a blank password originally
10278 * and the real password subsequently, so,
10279 * reluctantly, we prompt for the old password again.
10281 * (On the other hand, some servers don't even bother
10282 * to check this field.)
10284 add_prompt(s->cur_prompt,
10285 dupstr("Current password (blank for previously entered password): "),
10287 add_prompt(s->cur_prompt, dupstr("Enter new password: "),
10289 add_prompt(s->cur_prompt, dupstr("Confirm new password: "),
10293 * Loop until the user manages to enter the same
10298 ret = get_userpass_input(s->cur_prompt, NULL, 0);
10301 crWaitUntilV(!pktin);
10302 ret = get_userpass_input(s->cur_prompt, in, inlen);
10307 * Failed to get responses. Terminate.
10309 /* burn the evidence */
10310 free_prompts(s->cur_prompt);
10311 smemclr(s->password, strlen(s->password));
10312 sfree(s->password);
10313 ssh_disconnect(ssh, NULL, "Unable to authenticate",
10314 SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER,
10320 * If the user specified a new original password
10321 * (IYSWIM), overwrite any previously specified
10323 * (A side effect is that the user doesn't have to
10324 * re-enter it if they louse up the new password.)
10326 if (s->cur_prompt->prompts[0]->result[0]) {
10327 smemclr(s->password, strlen(s->password));
10328 /* burn the evidence */
10329 sfree(s->password);
10331 dupstr(s->cur_prompt->prompts[0]->result);
10335 * Check the two new passwords match.
10337 got_new = (strcmp(s->cur_prompt->prompts[1]->result,
10338 s->cur_prompt->prompts[2]->result)
10341 /* They don't. Silly user. */
10342 c_write_str(ssh, "Passwords do not match\r\n");
10347 * Send the new password (along with the old one).
10348 * (see above for padding rationale)
10350 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
10351 ssh2_pkt_addstring(s->pktout, ssh->username);
10352 ssh2_pkt_addstring(s->pktout, "ssh-connection");
10353 /* service requested */
10354 ssh2_pkt_addstring(s->pktout, "password");
10355 ssh2_pkt_addbool(s->pktout, TRUE);
10356 ssh2_pkt_addstring(s->pktout, s->password);
10357 ssh2_pkt_addstring(s->pktout,
10358 s->cur_prompt->prompts[1]->result);
10359 free_prompts(s->cur_prompt);
10360 ssh2_pkt_send_with_padding(ssh, s->pktout, 256);
10361 logevent("Sent new password");
10364 * Now see what the server has to say about it.
10365 * (If it's CHANGEREQ again, it's not happy with the
10368 crWaitUntilV(pktin);
10369 changereq_first_time = FALSE;
10374 * We need to reexamine the current pktin at the top
10375 * of the loop. Either:
10376 * - we weren't asked to change password at all, in
10377 * which case it's a SUCCESS or FAILURE with the
10379 * - we sent a new password, and the server was
10380 * either OK with it (SUCCESS or FAILURE w/partial
10381 * success) or unhappy with the _old_ password
10382 * (FAILURE w/o partial success)
10383 * In any of these cases, we go back to the top of
10384 * the loop and start again.
10389 * We don't need the old password any more, in any
10390 * case. Burn the evidence.
10392 smemclr(s->password, strlen(s->password));
10393 sfree(s->password);
10396 char *str = dupprintf("No supported authentication methods available"
10397 " (server sent: %.*s)",
10400 ssh_disconnect(ssh, str,
10401 "No supported authentication methods available",
10402 SSH2_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE,
10412 ssh->packet_dispatch[SSH2_MSG_USERAUTH_BANNER] = NULL;
10414 /* Clear up various bits and pieces from authentication. */
10415 if (s->publickey_blob) {
10416 sfree(s->publickey_algorithm);
10417 sfree(s->publickey_blob);
10418 sfree(s->publickey_comment);
10420 if (s->agent_response)
10421 sfree(s->agent_response);
10423 if (s->userauth_success && !ssh->bare_connection) {
10425 * We've just received USERAUTH_SUCCESS, and we haven't sent any
10426 * packets since. Signal the transport layer to consider enacting
10427 * delayed compression.
10429 * (Relying on we_are_in is not sufficient, as
10430 * draft-miller-secsh-compression-delayed is quite clear that it
10431 * triggers on USERAUTH_SUCCESS specifically, and we_are_in can
10432 * become set for other reasons.)
10434 do_ssh2_transport(ssh, "enabling delayed compression", -2, NULL);
10437 ssh->channels = newtree234(ssh_channelcmp);
10440 * Set up handlers for some connection protocol messages, so we
10441 * don't have to handle them repeatedly in this coroutine.
10443 ssh->packet_dispatch[SSH2_MSG_CHANNEL_WINDOW_ADJUST] =
10444 ssh2_msg_channel_window_adjust;
10445 ssh->packet_dispatch[SSH2_MSG_GLOBAL_REQUEST] =
10446 ssh2_msg_global_request;
10449 * Create the main session channel.
10451 if (conf_get_int(ssh->conf, CONF_ssh_no_shell)) {
10452 ssh->mainchan = NULL;
10454 ssh->mainchan = snew(struct ssh_channel);
10455 ssh->mainchan->ssh = ssh;
10456 ssh2_channel_init(ssh->mainchan);
10458 if (*conf_get_str(ssh->conf, CONF_ssh_nc_host)) {
10460 * Just start a direct-tcpip channel and use it as the main
10463 ssh_send_port_open(ssh->mainchan,
10464 conf_get_str(ssh->conf, CONF_ssh_nc_host),
10465 conf_get_int(ssh->conf, CONF_ssh_nc_port),
10467 ssh->ncmode = TRUE;
10469 s->pktout = ssh2_chanopen_init(ssh->mainchan, "session");
10470 logevent("Opening session as main channel");
10471 ssh2_pkt_send(ssh, s->pktout);
10472 ssh->ncmode = FALSE;
10474 crWaitUntilV(pktin);
10475 if (pktin->type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
10476 bombout(("Server refused to open channel"));
10478 /* FIXME: error data comes back in FAILURE packet */
10480 if (ssh_pkt_getuint32(pktin) != ssh->mainchan->localid) {
10481 bombout(("Server's channel confirmation cited wrong channel"));
10484 ssh->mainchan->remoteid = ssh_pkt_getuint32(pktin);
10485 ssh->mainchan->halfopen = FALSE;
10486 ssh->mainchan->type = CHAN_MAINSESSION;
10487 ssh->mainchan->v.v2.remwindow = ssh_pkt_getuint32(pktin);
10488 ssh->mainchan->v.v2.remmaxpkt = ssh_pkt_getuint32(pktin);
10489 add234(ssh->channels, ssh->mainchan);
10490 update_specials_menu(ssh->frontend);
10491 logevent("Opened main channel");
10495 * Now we have a channel, make dispatch table entries for
10496 * general channel-based messages.
10498 ssh->packet_dispatch[SSH2_MSG_CHANNEL_DATA] =
10499 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EXTENDED_DATA] =
10500 ssh2_msg_channel_data;
10501 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EOF] = ssh2_msg_channel_eof;
10502 ssh->packet_dispatch[SSH2_MSG_CHANNEL_CLOSE] = ssh2_msg_channel_close;
10503 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_CONFIRMATION] =
10504 ssh2_msg_channel_open_confirmation;
10505 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_FAILURE] =
10506 ssh2_msg_channel_open_failure;
10507 ssh->packet_dispatch[SSH2_MSG_CHANNEL_REQUEST] =
10508 ssh2_msg_channel_request;
10509 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN] =
10510 ssh2_msg_channel_open;
10511 ssh->packet_dispatch[SSH2_MSG_CHANNEL_SUCCESS] = ssh2_msg_channel_response;
10512 ssh->packet_dispatch[SSH2_MSG_CHANNEL_FAILURE] = ssh2_msg_channel_response;
10515 * Now the connection protocol is properly up and running, with
10516 * all those dispatch table entries, so it's safe to let
10517 * downstreams start trying to open extra channels through us.
10519 if (ssh->connshare)
10520 share_activate(ssh->connshare, ssh->v_s);
10522 if (ssh->mainchan && ssh_is_simple(ssh)) {
10524 * This message indicates to the server that we promise
10525 * not to try to run any other channel in parallel with
10526 * this one, so it's safe for it to advertise a very large
10527 * window and leave the flow control to TCP.
10529 s->pktout = ssh2_chanreq_init(ssh->mainchan,
10530 "simple@putty.projects.tartarus.org",
10532 ssh2_pkt_send(ssh, s->pktout);
10536 * Enable port forwardings.
10538 ssh_setup_portfwd(ssh, ssh->conf);
10540 if (ssh->mainchan && !ssh->ncmode) {
10542 * Send the CHANNEL_REQUESTS for the main session channel.
10543 * Each one is handled by its own little asynchronous
10547 /* Potentially enable X11 forwarding. */
10548 if (conf_get_int(ssh->conf, CONF_x11_forward)) {
10550 x11_setup_display(conf_get_str(ssh->conf, CONF_x11_display),
10552 if (!ssh->x11disp) {
10553 /* FIXME: return an error message from x11_setup_display */
10554 logevent("X11 forwarding not enabled: unable to"
10555 " initialise X display");
10557 ssh->x11auth = x11_invent_fake_auth
10558 (ssh->x11authtree, conf_get_int(ssh->conf, CONF_x11_auth));
10559 ssh->x11auth->disp = ssh->x11disp;
10561 ssh2_setup_x11(ssh->mainchan, NULL, NULL);
10565 /* Potentially enable agent forwarding. */
10566 if (ssh_agent_forwarding_permitted(ssh))
10567 ssh2_setup_agent(ssh->mainchan, NULL, NULL);
10569 /* Now allocate a pty for the session. */
10570 if (!conf_get_int(ssh->conf, CONF_nopty))
10571 ssh2_setup_pty(ssh->mainchan, NULL, NULL);
10573 /* Send environment variables. */
10574 ssh2_setup_env(ssh->mainchan, NULL, NULL);
10577 * Start a shell or a remote command. We may have to attempt
10578 * this twice if the config data has provided a second choice
10585 if (ssh->fallback_cmd) {
10586 subsys = conf_get_int(ssh->conf, CONF_ssh_subsys2);
10587 cmd = conf_get_str(ssh->conf, CONF_remote_cmd2);
10589 subsys = conf_get_int(ssh->conf, CONF_ssh_subsys);
10590 cmd = conf_get_str(ssh->conf, CONF_remote_cmd);
10594 s->pktout = ssh2_chanreq_init(ssh->mainchan, "subsystem",
10595 ssh2_response_authconn, NULL);
10596 ssh2_pkt_addstring(s->pktout, cmd);
10598 s->pktout = ssh2_chanreq_init(ssh->mainchan, "exec",
10599 ssh2_response_authconn, NULL);
10600 ssh2_pkt_addstring(s->pktout, cmd);
10602 s->pktout = ssh2_chanreq_init(ssh->mainchan, "shell",
10603 ssh2_response_authconn, NULL);
10605 ssh2_pkt_send(ssh, s->pktout);
10607 crWaitUntilV(pktin);
10609 if (pktin->type != SSH2_MSG_CHANNEL_SUCCESS) {
10610 if (pktin->type != SSH2_MSG_CHANNEL_FAILURE) {
10611 bombout(("Unexpected response to shell/command request:"
10612 " packet type %d", pktin->type));
10616 * We failed to start the command. If this is the
10617 * fallback command, we really are finished; if it's
10618 * not, and if the fallback command exists, try falling
10619 * back to it before complaining.
10621 if (!ssh->fallback_cmd &&
10622 *conf_get_str(ssh->conf, CONF_remote_cmd2)) {
10623 logevent("Primary command failed; attempting fallback");
10624 ssh->fallback_cmd = TRUE;
10627 bombout(("Server refused to start a shell/command"));
10630 logevent("Started a shell/command");
10635 ssh->editing = ssh->echoing = TRUE;
10638 ssh->state = SSH_STATE_SESSION;
10639 if (ssh->size_needed)
10640 ssh_size(ssh, ssh->term_width, ssh->term_height);
10641 if (ssh->eof_needed)
10642 ssh_special(ssh, TS_EOF);
10648 ldisc_echoedit_update(ssh->ldisc); /* cause ldisc to notice changes */
10653 s->try_send = FALSE;
10657 * _All_ the connection-layer packets we expect to
10658 * receive are now handled by the dispatch table.
10659 * Anything that reaches here must be bogus.
10662 bombout(("Strange packet received: type %d", pktin->type));
10664 } else if (ssh->mainchan) {
10666 * We have spare data. Add it to the channel buffer.
10668 ssh2_add_channel_data(ssh->mainchan, (char *)in, inlen);
10669 s->try_send = TRUE;
10673 struct ssh_channel *c;
10675 * Try to send data on all channels if we can.
10677 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++)
10678 if (c->type != CHAN_SHARING)
10679 ssh2_try_send_and_unthrottle(ssh, c);
10687 * Handlers for SSH-2 messages that might arrive at any moment.
10689 static void ssh2_msg_disconnect(Ssh ssh, struct Packet *pktin)
10691 /* log reason code in disconnect message */
10693 int reason, msglen;
10695 reason = ssh_pkt_getuint32(pktin);
10696 ssh_pkt_getstring(pktin, &msg, &msglen);
10698 if (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) {
10699 buf = dupprintf("Received disconnect message (%s)",
10700 ssh2_disconnect_reasons[reason]);
10702 buf = dupprintf("Received disconnect message (unknown"
10703 " type %d)", reason);
10707 buf = dupprintf("Disconnection message text: %.*s",
10710 bombout(("Server sent disconnect message\ntype %d (%s):\n\"%.*s\"",
10712 (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) ?
10713 ssh2_disconnect_reasons[reason] : "unknown",
10718 static void ssh2_msg_debug(Ssh ssh, struct Packet *pktin)
10720 /* log the debug message */
10724 /* XXX maybe we should actually take notice of the return value */
10725 ssh2_pkt_getbool(pktin);
10726 ssh_pkt_getstring(pktin, &msg, &msglen);
10728 logeventf(ssh, "Remote debug message: %.*s", msglen, msg);
10731 static void ssh2_msg_transport(Ssh ssh, struct Packet *pktin)
10733 do_ssh2_transport(ssh, NULL, 0, pktin);
10737 * Called if we receive a packet that isn't allowed by the protocol.
10738 * This only applies to packets whose meaning PuTTY understands.
10739 * Entirely unknown packets are handled below.
10741 static void ssh2_msg_unexpected(Ssh ssh, struct Packet *pktin)
10743 char *buf = dupprintf("Server protocol violation: unexpected %s packet",
10744 ssh2_pkt_type(ssh->pkt_kctx, ssh->pkt_actx,
10746 ssh_disconnect(ssh, NULL, buf, SSH2_DISCONNECT_PROTOCOL_ERROR, FALSE);
10750 static void ssh2_msg_something_unimplemented(Ssh ssh, struct Packet *pktin)
10752 struct Packet *pktout;
10753 pktout = ssh2_pkt_init(SSH2_MSG_UNIMPLEMENTED);
10754 ssh2_pkt_adduint32(pktout, pktin->sequence);
10756 * UNIMPLEMENTED messages MUST appear in the same order as the
10757 * messages they respond to. Hence, never queue them.
10759 ssh2_pkt_send_noqueue(ssh, pktout);
10763 * Handle the top-level SSH-2 protocol.
10765 static void ssh2_protocol_setup(Ssh ssh)
10770 * Most messages cause SSH2_MSG_UNIMPLEMENTED.
10772 for (i = 0; i < 256; i++)
10773 ssh->packet_dispatch[i] = ssh2_msg_something_unimplemented;
10776 * Initially, we only accept transport messages (and a few generic
10777 * ones). do_ssh2_authconn will add more when it starts.
10778 * Messages that are understood but not currently acceptable go to
10779 * ssh2_msg_unexpected.
10781 ssh->packet_dispatch[SSH2_MSG_UNIMPLEMENTED] = ssh2_msg_unexpected;
10782 ssh->packet_dispatch[SSH2_MSG_SERVICE_REQUEST] = ssh2_msg_unexpected;
10783 ssh->packet_dispatch[SSH2_MSG_SERVICE_ACCEPT] = ssh2_msg_unexpected;
10784 ssh->packet_dispatch[SSH2_MSG_KEXINIT] = ssh2_msg_transport;
10785 ssh->packet_dispatch[SSH2_MSG_NEWKEYS] = ssh2_msg_transport;
10786 ssh->packet_dispatch[SSH2_MSG_KEXDH_INIT] = ssh2_msg_transport;
10787 ssh->packet_dispatch[SSH2_MSG_KEXDH_REPLY] = ssh2_msg_transport;
10788 /* ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_REQUEST] = ssh2_msg_transport; duplicate case value */
10789 /* ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_GROUP] = ssh2_msg_transport; duplicate case value */
10790 ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_INIT] = ssh2_msg_transport;
10791 ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_REPLY] = ssh2_msg_transport;
10792 ssh->packet_dispatch[SSH2_MSG_USERAUTH_REQUEST] = ssh2_msg_unexpected;
10793 ssh->packet_dispatch[SSH2_MSG_USERAUTH_FAILURE] = ssh2_msg_unexpected;
10794 ssh->packet_dispatch[SSH2_MSG_USERAUTH_SUCCESS] = ssh2_msg_unexpected;
10795 ssh->packet_dispatch[SSH2_MSG_USERAUTH_BANNER] = ssh2_msg_unexpected;
10796 ssh->packet_dispatch[SSH2_MSG_USERAUTH_PK_OK] = ssh2_msg_unexpected;
10797 /* ssh->packet_dispatch[SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ] = ssh2_msg_unexpected; duplicate case value */
10798 /* ssh->packet_dispatch[SSH2_MSG_USERAUTH_INFO_REQUEST] = ssh2_msg_unexpected; duplicate case value */
10799 ssh->packet_dispatch[SSH2_MSG_USERAUTH_INFO_RESPONSE] = ssh2_msg_unexpected;
10800 ssh->packet_dispatch[SSH2_MSG_GLOBAL_REQUEST] = ssh2_msg_unexpected;
10801 ssh->packet_dispatch[SSH2_MSG_REQUEST_SUCCESS] = ssh2_msg_unexpected;
10802 ssh->packet_dispatch[SSH2_MSG_REQUEST_FAILURE] = ssh2_msg_unexpected;
10803 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN] = ssh2_msg_unexpected;
10804 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_CONFIRMATION] = ssh2_msg_unexpected;
10805 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_FAILURE] = ssh2_msg_unexpected;
10806 ssh->packet_dispatch[SSH2_MSG_CHANNEL_WINDOW_ADJUST] = ssh2_msg_unexpected;
10807 ssh->packet_dispatch[SSH2_MSG_CHANNEL_DATA] = ssh2_msg_unexpected;
10808 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EXTENDED_DATA] = ssh2_msg_unexpected;
10809 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EOF] = ssh2_msg_unexpected;
10810 ssh->packet_dispatch[SSH2_MSG_CHANNEL_CLOSE] = ssh2_msg_unexpected;
10811 ssh->packet_dispatch[SSH2_MSG_CHANNEL_REQUEST] = ssh2_msg_unexpected;
10812 ssh->packet_dispatch[SSH2_MSG_CHANNEL_SUCCESS] = ssh2_msg_unexpected;
10813 ssh->packet_dispatch[SSH2_MSG_CHANNEL_FAILURE] = ssh2_msg_unexpected;
10816 * These messages have a special handler from the start.
10818 ssh->packet_dispatch[SSH2_MSG_DISCONNECT] = ssh2_msg_disconnect;
10819 ssh->packet_dispatch[SSH2_MSG_IGNORE] = ssh_msg_ignore; /* shared with SSH-1 */
10820 ssh->packet_dispatch[SSH2_MSG_DEBUG] = ssh2_msg_debug;
10823 static void ssh2_bare_connection_protocol_setup(Ssh ssh)
10828 * Most messages cause SSH2_MSG_UNIMPLEMENTED.
10830 for (i = 0; i < 256; i++)
10831 ssh->packet_dispatch[i] = ssh2_msg_something_unimplemented;
10834 * Initially, we set all ssh-connection messages to 'unexpected';
10835 * do_ssh2_authconn will fill things in properly. We also handle a
10836 * couple of messages from the transport protocol which aren't
10837 * related to key exchange (UNIMPLEMENTED, IGNORE, DEBUG,
10840 ssh->packet_dispatch[SSH2_MSG_GLOBAL_REQUEST] = ssh2_msg_unexpected;
10841 ssh->packet_dispatch[SSH2_MSG_REQUEST_SUCCESS] = ssh2_msg_unexpected;
10842 ssh->packet_dispatch[SSH2_MSG_REQUEST_FAILURE] = ssh2_msg_unexpected;
10843 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN] = ssh2_msg_unexpected;
10844 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_CONFIRMATION] = ssh2_msg_unexpected;
10845 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_FAILURE] = ssh2_msg_unexpected;
10846 ssh->packet_dispatch[SSH2_MSG_CHANNEL_WINDOW_ADJUST] = ssh2_msg_unexpected;
10847 ssh->packet_dispatch[SSH2_MSG_CHANNEL_DATA] = ssh2_msg_unexpected;
10848 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EXTENDED_DATA] = ssh2_msg_unexpected;
10849 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EOF] = ssh2_msg_unexpected;
10850 ssh->packet_dispatch[SSH2_MSG_CHANNEL_CLOSE] = ssh2_msg_unexpected;
10851 ssh->packet_dispatch[SSH2_MSG_CHANNEL_REQUEST] = ssh2_msg_unexpected;
10852 ssh->packet_dispatch[SSH2_MSG_CHANNEL_SUCCESS] = ssh2_msg_unexpected;
10853 ssh->packet_dispatch[SSH2_MSG_CHANNEL_FAILURE] = ssh2_msg_unexpected;
10855 ssh->packet_dispatch[SSH2_MSG_UNIMPLEMENTED] = ssh2_msg_unexpected;
10858 * These messages have a special handler from the start.
10860 ssh->packet_dispatch[SSH2_MSG_DISCONNECT] = ssh2_msg_disconnect;
10861 ssh->packet_dispatch[SSH2_MSG_IGNORE] = ssh_msg_ignore;
10862 ssh->packet_dispatch[SSH2_MSG_DEBUG] = ssh2_msg_debug;
10865 static void ssh2_timer(void *ctx, unsigned long now)
10867 Ssh ssh = (Ssh)ctx;
10869 if (ssh->state == SSH_STATE_CLOSED)
10872 if (!ssh->kex_in_progress && !ssh->bare_connection &&
10873 conf_get_int(ssh->conf, CONF_ssh_rekey_time) != 0 &&
10874 now == ssh->next_rekey) {
10875 do_ssh2_transport(ssh, "timeout", -1, NULL);
10879 static void ssh2_protocol(Ssh ssh, const void *vin, int inlen,
10880 struct Packet *pktin)
10882 const unsigned char *in = (const unsigned char *)vin;
10883 if (ssh->state == SSH_STATE_CLOSED)
10887 ssh->incoming_data_size += pktin->encrypted_len;
10888 if (!ssh->kex_in_progress &&
10889 ssh->max_data_size != 0 &&
10890 ssh->incoming_data_size > ssh->max_data_size)
10891 do_ssh2_transport(ssh, "too much data received", -1, NULL);
10895 ssh->packet_dispatch[pktin->type](ssh, pktin);
10896 else if (!ssh->protocol_initial_phase_done)
10897 do_ssh2_transport(ssh, in, inlen, pktin);
10899 do_ssh2_authconn(ssh, in, inlen, pktin);
10902 static void ssh2_bare_connection_protocol(Ssh ssh, const void *vin, int inlen,
10903 struct Packet *pktin)
10905 const unsigned char *in = (const unsigned char *)vin;
10906 if (ssh->state == SSH_STATE_CLOSED)
10910 ssh->packet_dispatch[pktin->type](ssh, pktin);
10912 do_ssh2_authconn(ssh, in, inlen, pktin);
10915 static void ssh_cache_conf_values(Ssh ssh)
10917 ssh->logomitdata = conf_get_int(ssh->conf, CONF_logomitdata);
10921 * Called to set up the connection.
10923 * Returns an error message, or NULL on success.
10925 static const char *ssh_init(void *frontend_handle, void **backend_handle,
10927 const char *host, int port, char **realhost,
10928 int nodelay, int keepalive)
10933 ssh = snew(struct ssh_tag);
10934 ssh->conf = conf_copy(conf);
10935 ssh_cache_conf_values(ssh);
10936 ssh->version = 0; /* when not ready yet */
10938 ssh->cipher = NULL;
10939 ssh->v1_cipher_ctx = NULL;
10940 ssh->crcda_ctx = NULL;
10941 ssh->cscipher = NULL;
10942 ssh->cs_cipher_ctx = NULL;
10943 ssh->sccipher = NULL;
10944 ssh->sc_cipher_ctx = NULL;
10946 ssh->cs_mac_ctx = NULL;
10948 ssh->sc_mac_ctx = NULL;
10949 ssh->cscomp = NULL;
10950 ssh->cs_comp_ctx = NULL;
10951 ssh->sccomp = NULL;
10952 ssh->sc_comp_ctx = NULL;
10954 ssh->kex_ctx = NULL;
10955 ssh->hostkey = NULL;
10956 ssh->hostkey_str = NULL;
10957 ssh->exitcode = -1;
10958 ssh->close_expected = FALSE;
10959 ssh->clean_exit = FALSE;
10960 ssh->state = SSH_STATE_PREPACKET;
10961 ssh->size_needed = FALSE;
10962 ssh->eof_needed = FALSE;
10964 ssh->logctx = NULL;
10965 ssh->deferred_send_data = NULL;
10966 ssh->deferred_len = 0;
10967 ssh->deferred_size = 0;
10968 ssh->fallback_cmd = 0;
10969 ssh->pkt_kctx = SSH2_PKTCTX_NOKEX;
10970 ssh->pkt_actx = SSH2_PKTCTX_NOAUTH;
10971 ssh->x11disp = NULL;
10972 ssh->x11auth = NULL;
10973 ssh->x11authtree = newtree234(x11_authcmp);
10974 ssh->v1_compressing = FALSE;
10975 ssh->v2_outgoing_sequence = 0;
10976 ssh->ssh1_rdpkt_crstate = 0;
10977 ssh->ssh2_rdpkt_crstate = 0;
10978 ssh->ssh2_bare_rdpkt_crstate = 0;
10979 ssh->ssh_gotdata_crstate = 0;
10980 ssh->do_ssh1_connection_crstate = 0;
10981 ssh->do_ssh_init_state = NULL;
10982 ssh->do_ssh_connection_init_state = NULL;
10983 ssh->do_ssh1_login_state = NULL;
10984 ssh->do_ssh2_transport_state = NULL;
10985 ssh->do_ssh2_authconn_state = NULL;
10988 ssh->mainchan = NULL;
10989 ssh->throttled_all = 0;
10990 ssh->v1_stdout_throttling = 0;
10992 ssh->queuelen = ssh->queuesize = 0;
10993 ssh->queueing = FALSE;
10994 ssh->qhead = ssh->qtail = NULL;
10995 ssh->deferred_rekey_reason = NULL;
10996 bufchain_init(&ssh->queued_incoming_data);
10997 ssh->frozen = FALSE;
10998 ssh->username = NULL;
10999 ssh->sent_console_eof = FALSE;
11000 ssh->got_pty = FALSE;
11001 ssh->bare_connection = FALSE;
11002 ssh->X11_fwd_enabled = FALSE;
11003 ssh->connshare = NULL;
11004 ssh->attempting_connshare = FALSE;
11005 ssh->session_started = FALSE;
11007 *backend_handle = ssh;
11010 if (crypto_startup() == 0)
11011 return "Microsoft high encryption pack not installed!";
11014 ssh->frontend = frontend_handle;
11015 ssh->term_width = conf_get_int(ssh->conf, CONF_width);
11016 ssh->term_height = conf_get_int(ssh->conf, CONF_height);
11018 ssh->channels = NULL;
11019 ssh->rportfwds = NULL;
11020 ssh->portfwds = NULL;
11025 ssh->conn_throttle_count = 0;
11026 ssh->overall_bufsize = 0;
11027 ssh->fallback_cmd = 0;
11029 ssh->protocol = NULL;
11031 ssh->protocol_initial_phase_done = FALSE;
11033 ssh->pinger = NULL;
11035 ssh->incoming_data_size = ssh->outgoing_data_size =
11036 ssh->deferred_data_size = 0L;
11037 ssh->max_data_size = parse_blocksize(conf_get_str(ssh->conf,
11038 CONF_ssh_rekey_data));
11039 ssh->kex_in_progress = FALSE;
11042 ssh->gsslibs = NULL;
11045 random_ref(); /* do this now - may be needed by sharing setup code */
11047 p = connect_to_host(ssh, host, port, realhost, nodelay, keepalive);
11056 static void ssh_free(void *handle)
11058 Ssh ssh = (Ssh) handle;
11059 struct ssh_channel *c;
11060 struct ssh_rportfwd *pf;
11061 struct X11FakeAuth *auth;
11063 if (ssh->v1_cipher_ctx)
11064 ssh->cipher->free_context(ssh->v1_cipher_ctx);
11065 if (ssh->cs_cipher_ctx)
11066 ssh->cscipher->free_context(ssh->cs_cipher_ctx);
11067 if (ssh->sc_cipher_ctx)
11068 ssh->sccipher->free_context(ssh->sc_cipher_ctx);
11069 if (ssh->cs_mac_ctx)
11070 ssh->csmac->free_context(ssh->cs_mac_ctx);
11071 if (ssh->sc_mac_ctx)
11072 ssh->scmac->free_context(ssh->sc_mac_ctx);
11073 if (ssh->cs_comp_ctx) {
11075 ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
11077 zlib_compress_cleanup(ssh->cs_comp_ctx);
11079 if (ssh->sc_comp_ctx) {
11081 ssh->sccomp->decompress_cleanup(ssh->sc_comp_ctx);
11083 zlib_decompress_cleanup(ssh->sc_comp_ctx);
11086 dh_cleanup(ssh->kex_ctx);
11087 sfree(ssh->savedhost);
11089 while (ssh->queuelen-- > 0)
11090 ssh_free_packet(ssh->queue[ssh->queuelen]);
11093 while (ssh->qhead) {
11094 struct queued_handler *qh = ssh->qhead;
11095 ssh->qhead = qh->next;
11098 ssh->qhead = ssh->qtail = NULL;
11100 if (ssh->channels) {
11101 while ((c = delpos234(ssh->channels, 0)) != NULL) {
11104 if (c->u.x11.xconn != NULL)
11105 x11_close(c->u.x11.xconn);
11107 case CHAN_SOCKDATA:
11108 case CHAN_SOCKDATA_DORMANT:
11109 if (c->u.pfd.pf != NULL)
11110 pfd_close(c->u.pfd.pf);
11113 if (ssh->version == 2) {
11114 struct outstanding_channel_request *ocr, *nocr;
11115 ocr = c->v.v2.chanreq_head;
11117 ocr->handler(c, NULL, ocr->ctx);
11122 bufchain_clear(&c->v.v2.outbuffer);
11126 freetree234(ssh->channels);
11127 ssh->channels = NULL;
11130 if (ssh->connshare)
11131 sharestate_free(ssh->connshare);
11133 if (ssh->rportfwds) {
11134 while ((pf = delpos234(ssh->rportfwds, 0)) != NULL)
11136 freetree234(ssh->rportfwds);
11137 ssh->rportfwds = NULL;
11139 sfree(ssh->deferred_send_data);
11141 x11_free_display(ssh->x11disp);
11142 while ((auth = delpos234(ssh->x11authtree, 0)) != NULL)
11143 x11_free_fake_auth(auth);
11144 freetree234(ssh->x11authtree);
11145 sfree(ssh->do_ssh_init_state);
11146 sfree(ssh->do_ssh1_login_state);
11147 sfree(ssh->do_ssh2_transport_state);
11148 sfree(ssh->do_ssh2_authconn_state);
11151 sfree(ssh->fullhostname);
11152 sfree(ssh->hostkey_str);
11153 if (ssh->crcda_ctx) {
11154 crcda_free_context(ssh->crcda_ctx);
11155 ssh->crcda_ctx = NULL;
11158 ssh_do_close(ssh, TRUE);
11159 expire_timer_context(ssh);
11161 pinger_free(ssh->pinger);
11162 bufchain_clear(&ssh->queued_incoming_data);
11163 sfree(ssh->username);
11164 conf_free(ssh->conf);
11167 ssh_gss_cleanup(ssh->gsslibs);
11175 * Reconfigure the SSH backend.
11177 static void ssh_reconfig(void *handle, Conf *conf)
11179 Ssh ssh = (Ssh) handle;
11180 const char *rekeying = NULL;
11181 int rekey_mandatory = FALSE;
11182 unsigned long old_max_data_size;
11185 pinger_reconfig(ssh->pinger, ssh->conf, conf);
11187 ssh_setup_portfwd(ssh, conf);
11189 rekey_time = conf_get_int(conf, CONF_ssh_rekey_time);
11190 if (conf_get_int(ssh->conf, CONF_ssh_rekey_time) != rekey_time &&
11192 unsigned long new_next = ssh->last_rekey + rekey_time*60*TICKSPERSEC;
11193 unsigned long now = GETTICKCOUNT();
11195 if (now - ssh->last_rekey > rekey_time*60*TICKSPERSEC) {
11196 rekeying = "timeout shortened";
11198 ssh->next_rekey = schedule_timer(new_next - now, ssh2_timer, ssh);
11202 old_max_data_size = ssh->max_data_size;
11203 ssh->max_data_size = parse_blocksize(conf_get_str(ssh->conf,
11204 CONF_ssh_rekey_data));
11205 if (old_max_data_size != ssh->max_data_size &&
11206 ssh->max_data_size != 0) {
11207 if (ssh->outgoing_data_size > ssh->max_data_size ||
11208 ssh->incoming_data_size > ssh->max_data_size)
11209 rekeying = "data limit lowered";
11212 if (conf_get_int(ssh->conf, CONF_compression) !=
11213 conf_get_int(conf, CONF_compression)) {
11214 rekeying = "compression setting changed";
11215 rekey_mandatory = TRUE;
11218 for (i = 0; i < CIPHER_MAX; i++)
11219 if (conf_get_int_int(ssh->conf, CONF_ssh_cipherlist, i) !=
11220 conf_get_int_int(conf, CONF_ssh_cipherlist, i)) {
11221 rekeying = "cipher settings changed";
11222 rekey_mandatory = TRUE;
11224 if (conf_get_int(ssh->conf, CONF_ssh2_des_cbc) !=
11225 conf_get_int(conf, CONF_ssh2_des_cbc)) {
11226 rekeying = "cipher settings changed";
11227 rekey_mandatory = TRUE;
11230 conf_free(ssh->conf);
11231 ssh->conf = conf_copy(conf);
11232 ssh_cache_conf_values(ssh);
11234 if (!ssh->bare_connection && rekeying) {
11235 if (!ssh->kex_in_progress) {
11236 do_ssh2_transport(ssh, rekeying, -1, NULL);
11237 } else if (rekey_mandatory) {
11238 ssh->deferred_rekey_reason = rekeying;
11244 * Called to send data down the SSH connection.
11246 static int ssh_send(void *handle, const char *buf, int len)
11248 Ssh ssh = (Ssh) handle;
11250 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
11253 ssh->protocol(ssh, (const unsigned char *)buf, len, 0);
11255 return ssh_sendbuffer(ssh);
11259 * Called to query the current amount of buffered stdin data.
11261 static int ssh_sendbuffer(void *handle)
11263 Ssh ssh = (Ssh) handle;
11264 int override_value;
11266 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
11270 * If the SSH socket itself has backed up, add the total backup
11271 * size on that to any individual buffer on the stdin channel.
11273 override_value = 0;
11274 if (ssh->throttled_all)
11275 override_value = ssh->overall_bufsize;
11277 if (ssh->version == 1) {
11278 return override_value;
11279 } else if (ssh->version == 2) {
11280 if (!ssh->mainchan)
11281 return override_value;
11283 return (override_value +
11284 bufchain_size(&ssh->mainchan->v.v2.outbuffer));
11291 * Called to set the size of the window from SSH's POV.
11293 static void ssh_size(void *handle, int width, int height)
11295 Ssh ssh = (Ssh) handle;
11296 struct Packet *pktout;
11298 ssh->term_width = width;
11299 ssh->term_height = height;
11301 switch (ssh->state) {
11302 case SSH_STATE_BEFORE_SIZE:
11303 case SSH_STATE_PREPACKET:
11304 case SSH_STATE_CLOSED:
11305 break; /* do nothing */
11306 case SSH_STATE_INTERMED:
11307 ssh->size_needed = TRUE; /* buffer for later */
11309 case SSH_STATE_SESSION:
11310 if (!conf_get_int(ssh->conf, CONF_nopty)) {
11311 if (ssh->version == 1) {
11312 send_packet(ssh, SSH1_CMSG_WINDOW_SIZE,
11313 PKT_INT, ssh->term_height,
11314 PKT_INT, ssh->term_width,
11315 PKT_INT, 0, PKT_INT, 0, PKT_END);
11316 } else if (ssh->mainchan) {
11317 pktout = ssh2_chanreq_init(ssh->mainchan, "window-change",
11319 ssh2_pkt_adduint32(pktout, ssh->term_width);
11320 ssh2_pkt_adduint32(pktout, ssh->term_height);
11321 ssh2_pkt_adduint32(pktout, 0);
11322 ssh2_pkt_adduint32(pktout, 0);
11323 ssh2_pkt_send(ssh, pktout);
11331 * Return a list of the special codes that make sense in this
11334 static const struct telnet_special *ssh_get_specials(void *handle)
11336 static const struct telnet_special ssh1_ignore_special[] = {
11337 {"IGNORE message", TS_NOP}
11339 static const struct telnet_special ssh2_ignore_special[] = {
11340 {"IGNORE message", TS_NOP},
11342 static const struct telnet_special ssh2_rekey_special[] = {
11343 {"Repeat key exchange", TS_REKEY},
11345 static const struct telnet_special ssh2_session_specials[] = {
11348 /* These are the signal names defined by RFC 4254.
11349 * They include all the ISO C signals, but are a subset of the POSIX
11350 * required signals. */
11351 {"SIGINT (Interrupt)", TS_SIGINT},
11352 {"SIGTERM (Terminate)", TS_SIGTERM},
11353 {"SIGKILL (Kill)", TS_SIGKILL},
11354 {"SIGQUIT (Quit)", TS_SIGQUIT},
11355 {"SIGHUP (Hangup)", TS_SIGHUP},
11356 {"More signals", TS_SUBMENU},
11357 {"SIGABRT", TS_SIGABRT}, {"SIGALRM", TS_SIGALRM},
11358 {"SIGFPE", TS_SIGFPE}, {"SIGILL", TS_SIGILL},
11359 {"SIGPIPE", TS_SIGPIPE}, {"SIGSEGV", TS_SIGSEGV},
11360 {"SIGUSR1", TS_SIGUSR1}, {"SIGUSR2", TS_SIGUSR2},
11361 {NULL, TS_EXITMENU}
11363 static const struct telnet_special specials_end[] = {
11364 {NULL, TS_EXITMENU}
11366 /* XXX review this length for any changes: */
11367 static struct telnet_special ssh_specials[lenof(ssh2_ignore_special) +
11368 lenof(ssh2_rekey_special) +
11369 lenof(ssh2_session_specials) +
11370 lenof(specials_end)];
11371 Ssh ssh = (Ssh) handle;
11373 #define ADD_SPECIALS(name) \
11375 assert((i + lenof(name)) <= lenof(ssh_specials)); \
11376 memcpy(&ssh_specials[i], name, sizeof name); \
11377 i += lenof(name); \
11380 if (ssh->version == 1) {
11381 /* Don't bother offering IGNORE if we've decided the remote
11382 * won't cope with it, since we wouldn't bother sending it if
11384 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE))
11385 ADD_SPECIALS(ssh1_ignore_special);
11386 } else if (ssh->version == 2) {
11387 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH2_IGNORE))
11388 ADD_SPECIALS(ssh2_ignore_special);
11389 if (!(ssh->remote_bugs & BUG_SSH2_REKEY) && !ssh->bare_connection)
11390 ADD_SPECIALS(ssh2_rekey_special);
11392 ADD_SPECIALS(ssh2_session_specials);
11393 } /* else we're not ready yet */
11396 ADD_SPECIALS(specials_end);
11397 return ssh_specials;
11401 #undef ADD_SPECIALS
11405 * Send special codes. TS_EOF is useful for `plink', so you
11406 * can send an EOF and collect resulting output (e.g. `plink
11409 static void ssh_special(void *handle, Telnet_Special code)
11411 Ssh ssh = (Ssh) handle;
11412 struct Packet *pktout;
11414 if (code == TS_EOF) {
11415 if (ssh->state != SSH_STATE_SESSION) {
11417 * Buffer the EOF in case we are pre-SESSION, so we can
11418 * send it as soon as we reach SESSION.
11420 if (code == TS_EOF)
11421 ssh->eof_needed = TRUE;
11424 if (ssh->version == 1) {
11425 send_packet(ssh, SSH1_CMSG_EOF, PKT_END);
11426 } else if (ssh->mainchan) {
11427 sshfwd_write_eof(ssh->mainchan);
11428 ssh->send_ok = 0; /* now stop trying to read from stdin */
11430 logevent("Sent EOF message");
11431 } else if (code == TS_PING || code == TS_NOP) {
11432 if (ssh->state == SSH_STATE_CLOSED
11433 || ssh->state == SSH_STATE_PREPACKET) return;
11434 if (ssh->version == 1) {
11435 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE))
11436 send_packet(ssh, SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
11438 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH2_IGNORE)) {
11439 pktout = ssh2_pkt_init(SSH2_MSG_IGNORE);
11440 ssh2_pkt_addstring_start(pktout);
11441 ssh2_pkt_send_noqueue(ssh, pktout);
11444 } else if (code == TS_REKEY) {
11445 if (!ssh->kex_in_progress && !ssh->bare_connection &&
11446 ssh->version == 2) {
11447 do_ssh2_transport(ssh, "at user request", -1, NULL);
11449 } else if (code == TS_BRK) {
11450 if (ssh->state == SSH_STATE_CLOSED
11451 || ssh->state == SSH_STATE_PREPACKET) return;
11452 if (ssh->version == 1) {
11453 logevent("Unable to send BREAK signal in SSH-1");
11454 } else if (ssh->mainchan) {
11455 pktout = ssh2_chanreq_init(ssh->mainchan, "break", NULL, NULL);
11456 ssh2_pkt_adduint32(pktout, 0); /* default break length */
11457 ssh2_pkt_send(ssh, pktout);
11460 /* Is is a POSIX signal? */
11461 const char *signame = NULL;
11462 if (code == TS_SIGABRT) signame = "ABRT";
11463 if (code == TS_SIGALRM) signame = "ALRM";
11464 if (code == TS_SIGFPE) signame = "FPE";
11465 if (code == TS_SIGHUP) signame = "HUP";
11466 if (code == TS_SIGILL) signame = "ILL";
11467 if (code == TS_SIGINT) signame = "INT";
11468 if (code == TS_SIGKILL) signame = "KILL";
11469 if (code == TS_SIGPIPE) signame = "PIPE";
11470 if (code == TS_SIGQUIT) signame = "QUIT";
11471 if (code == TS_SIGSEGV) signame = "SEGV";
11472 if (code == TS_SIGTERM) signame = "TERM";
11473 if (code == TS_SIGUSR1) signame = "USR1";
11474 if (code == TS_SIGUSR2) signame = "USR2";
11475 /* The SSH-2 protocol does in principle support arbitrary named
11476 * signals, including signame@domain, but we don't support those. */
11478 /* It's a signal. */
11479 if (ssh->version == 2 && ssh->mainchan) {
11480 pktout = ssh2_chanreq_init(ssh->mainchan, "signal", NULL, NULL);
11481 ssh2_pkt_addstring(pktout, signame);
11482 ssh2_pkt_send(ssh, pktout);
11483 logeventf(ssh, "Sent signal SIG%s", signame);
11486 /* Never heard of it. Do nothing */
11491 void *new_sock_channel(void *handle, struct PortForwarding *pf)
11493 Ssh ssh = (Ssh) handle;
11494 struct ssh_channel *c;
11495 c = snew(struct ssh_channel);
11498 ssh2_channel_init(c);
11499 c->halfopen = TRUE;
11500 c->type = CHAN_SOCKDATA_DORMANT;/* identify channel type */
11502 add234(ssh->channels, c);
11506 unsigned ssh_alloc_sharing_channel(Ssh ssh, void *sharing_ctx)
11508 struct ssh_channel *c;
11509 c = snew(struct ssh_channel);
11512 ssh2_channel_init(c);
11513 c->type = CHAN_SHARING;
11514 c->u.sharing.ctx = sharing_ctx;
11515 add234(ssh->channels, c);
11519 void ssh_delete_sharing_channel(Ssh ssh, unsigned localid)
11521 struct ssh_channel *c;
11523 c = find234(ssh->channels, &localid, ssh_channelfind);
11525 ssh_channel_destroy(c);
11528 void ssh_send_packet_from_downstream(Ssh ssh, unsigned id, int type,
11529 const void *data, int datalen,
11530 const char *additional_log_text)
11532 struct Packet *pkt;
11534 pkt = ssh2_pkt_init(type);
11535 pkt->downstream_id = id;
11536 pkt->additional_log_text = additional_log_text;
11537 ssh2_pkt_adddata(pkt, data, datalen);
11538 ssh2_pkt_send(ssh, pkt);
11542 * This is called when stdout/stderr (the entity to which
11543 * from_backend sends data) manages to clear some backlog.
11545 static void ssh_unthrottle(void *handle, int bufsize)
11547 Ssh ssh = (Ssh) handle;
11550 if (ssh->version == 1) {
11551 if (ssh->v1_stdout_throttling && bufsize < SSH1_BUFFER_LIMIT) {
11552 ssh->v1_stdout_throttling = 0;
11553 ssh_throttle_conn(ssh, -1);
11556 if (ssh->mainchan) {
11557 ssh2_set_window(ssh->mainchan,
11558 bufsize < ssh->mainchan->v.v2.locmaxwin ?
11559 ssh->mainchan->v.v2.locmaxwin - bufsize : 0);
11560 if (ssh_is_simple(ssh))
11563 buflimit = ssh->mainchan->v.v2.locmaxwin;
11564 if (ssh->mainchan->throttling_conn && bufsize <= buflimit) {
11565 ssh->mainchan->throttling_conn = 0;
11566 ssh_throttle_conn(ssh, -1);
11572 * Now process any SSH connection data that was stashed in our
11573 * queue while we were frozen.
11575 ssh_process_queued_incoming_data(ssh);
11578 void ssh_send_port_open(void *channel, const char *hostname, int port,
11581 struct ssh_channel *c = (struct ssh_channel *)channel;
11583 struct Packet *pktout;
11585 logeventf(ssh, "Opening connection to %s:%d for %s", hostname, port, org);
11587 if (ssh->version == 1) {
11588 send_packet(ssh, SSH1_MSG_PORT_OPEN,
11589 PKT_INT, c->localid,
11592 /* PKT_STR, <org:orgport>, */
11595 pktout = ssh2_chanopen_init(c, "direct-tcpip");
11597 char *trimmed_host = host_strduptrim(hostname);
11598 ssh2_pkt_addstring(pktout, trimmed_host);
11599 sfree(trimmed_host);
11601 ssh2_pkt_adduint32(pktout, port);
11603 * We make up values for the originator data; partly it's
11604 * too much hassle to keep track, and partly I'm not
11605 * convinced the server should be told details like that
11606 * about my local network configuration.
11607 * The "originator IP address" is syntactically a numeric
11608 * IP address, and some servers (e.g., Tectia) get upset
11609 * if it doesn't match this syntax.
11611 ssh2_pkt_addstring(pktout, "0.0.0.0");
11612 ssh2_pkt_adduint32(pktout, 0);
11613 ssh2_pkt_send(ssh, pktout);
11617 static int ssh_connected(void *handle)
11619 Ssh ssh = (Ssh) handle;
11620 return ssh->s != NULL;
11623 static int ssh_sendok(void *handle)
11625 Ssh ssh = (Ssh) handle;
11626 return ssh->send_ok;
11629 static int ssh_ldisc(void *handle, int option)
11631 Ssh ssh = (Ssh) handle;
11632 if (option == LD_ECHO)
11633 return ssh->echoing;
11634 if (option == LD_EDIT)
11635 return ssh->editing;
11639 static void ssh_provide_ldisc(void *handle, void *ldisc)
11641 Ssh ssh = (Ssh) handle;
11642 ssh->ldisc = ldisc;
11645 static void ssh_provide_logctx(void *handle, void *logctx)
11647 Ssh ssh = (Ssh) handle;
11648 ssh->logctx = logctx;
11651 static int ssh_return_exitcode(void *handle)
11653 Ssh ssh = (Ssh) handle;
11654 if (ssh->s != NULL)
11657 return (ssh->exitcode >= 0 ? ssh->exitcode : INT_MAX);
11661 * cfg_info for SSH is the protocol running in this session.
11662 * (1 or 2 for the full SSH-1 or SSH-2 protocol; -1 for the bare
11663 * SSH-2 connection protocol, i.e. a downstream; 0 for not-decided-yet.)
11665 static int ssh_cfg_info(void *handle)
11667 Ssh ssh = (Ssh) handle;
11668 if (ssh->version == 0)
11669 return 0; /* don't know yet */
11670 else if (ssh->bare_connection)
11673 return ssh->version;
11677 * Gross hack: pscp will try to start SFTP but fall back to scp1 if
11678 * that fails. This variable is the means by which scp.c can reach
11679 * into the SSH code and find out which one it got.
11681 extern int ssh_fallback_cmd(void *handle)
11683 Ssh ssh = (Ssh) handle;
11684 return ssh->fallback_cmd;
11687 Backend ssh_backend = {
11697 ssh_return_exitcode,
11701 ssh_provide_logctx,
11704 ssh_test_for_upstream,