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;
797 int ospeed, ispeed; /* temporaries */
798 int term_width, term_height;
800 tree234 *channels; /* indexed by local id */
801 struct ssh_channel *mainchan; /* primary session channel */
802 int ncmode; /* is primary channel direct-tcpip? */
807 tree234 *rportfwds, *portfwds;
811 SSH_STATE_BEFORE_SIZE,
817 int size_needed, eof_needed;
818 int sent_console_eof;
819 int got_pty; /* affects EOF behaviour on main channel */
821 struct Packet **queue;
822 int queuelen, queuesize;
824 unsigned char *deferred_send_data;
825 int deferred_len, deferred_size;
828 * Gross hack: pscp will try to start SFTP but fall back to
829 * scp1 if that fails. This variable is the means by which
830 * scp.c can reach into the SSH code and find out which one it
835 bufchain banner; /* accumulates banners during do_ssh2_authconn */
840 struct X11Display *x11disp;
841 struct X11FakeAuth *x11auth;
842 tree234 *x11authtree;
845 int conn_throttle_count;
848 int v1_stdout_throttling;
849 unsigned long v2_outgoing_sequence;
851 int ssh1_rdpkt_crstate;
852 int ssh2_rdpkt_crstate;
853 int ssh2_bare_rdpkt_crstate;
854 int ssh_gotdata_crstate;
855 int do_ssh1_connection_crstate;
857 void *do_ssh_init_state;
858 void *do_ssh1_login_state;
859 void *do_ssh2_transport_state;
860 void *do_ssh2_authconn_state;
861 void *do_ssh_connection_init_state;
863 struct rdpkt1_state_tag rdpkt1_state;
864 struct rdpkt2_state_tag rdpkt2_state;
865 struct rdpkt2_bare_state_tag rdpkt2_bare_state;
867 /* SSH-1 and SSH-2 use this for different things, but both use it */
868 int protocol_initial_phase_done;
870 void (*protocol) (Ssh ssh, const void *vin, int inlen,
872 struct Packet *(*s_rdpkt) (Ssh ssh, const unsigned char **data,
874 int (*do_ssh_init)(Ssh ssh, unsigned char c);
877 * We maintain our own copy of a Conf structure here. That way,
878 * when we're passed a new one for reconfiguration, we can check
879 * the differences and potentially reconfigure port forwardings
880 * etc in mid-session.
885 * Values cached out of conf so as to avoid the tree234 lookup
886 * cost every time they're used.
891 * Dynamically allocated username string created during SSH
892 * login. Stored in here rather than in the coroutine state so
893 * that it'll be reliably freed if we shut down the SSH session
894 * at some unexpected moment.
899 * Used to transfer data back from async callbacks.
901 void *agent_response;
902 int agent_response_len;
906 * The SSH connection can be set as `frozen', meaning we are
907 * not currently accepting incoming data from the network. This
908 * is slightly more serious than setting the _socket_ as
909 * frozen, because we may already have had data passed to us
910 * from the network which we need to delay processing until
911 * after the freeze is lifted, so we also need a bufchain to
915 bufchain queued_incoming_data;
918 * Dispatch table for packet types that we may have to deal
921 handler_fn_t packet_dispatch[256];
924 * Queues of one-off handler functions for success/failure
925 * indications from a request.
927 struct queued_handler *qhead, *qtail;
928 handler_fn_t q_saved_handler1, q_saved_handler2;
931 * This module deals with sending keepalives.
936 * Track incoming and outgoing data sizes and time, for
939 unsigned long incoming_data_size, outgoing_data_size, deferred_data_size;
940 unsigned long max_data_size;
942 unsigned long next_rekey, last_rekey;
943 const char *deferred_rekey_reason;
946 * Fully qualified host name, which we need if doing GSSAPI.
952 * GSSAPI libraries for this session.
954 struct ssh_gss_liblist *gsslibs;
958 #define logevent(s) logevent(ssh->frontend, s)
960 /* logevent, only printf-formatted. */
961 static void logeventf(Ssh ssh, const char *fmt, ...)
967 buf = dupvprintf(fmt, ap);
973 static void bomb_out(Ssh ssh, char *text)
975 ssh_do_close(ssh, FALSE);
977 connection_fatal(ssh->frontend, "%s", text);
981 #define bombout(msg) bomb_out(ssh, dupprintf msg)
983 /* Helper function for common bits of parsing ttymodes. */
984 static void parse_ttymodes(Ssh ssh,
985 void (*do_mode)(void *data, char *mode, char *val),
990 for (val = conf_get_str_strs(ssh->conf, CONF_ttymodes, NULL, &key);
992 val = conf_get_str_strs(ssh->conf, CONF_ttymodes, key, &key)) {
994 * val[0] is either 'V', indicating that an explicit value
995 * follows it, or 'A' indicating that we should pass the
996 * value through from the local environment via get_ttymode.
999 val = get_ttymode(ssh->frontend, key);
1001 do_mode(data, key, val);
1005 do_mode(data, key, val + 1); /* skip the 'V' */
1009 static int ssh_channelcmp(void *av, void *bv)
1011 struct ssh_channel *a = (struct ssh_channel *) av;
1012 struct ssh_channel *b = (struct ssh_channel *) bv;
1013 if (a->localid < b->localid)
1015 if (a->localid > b->localid)
1019 static int ssh_channelfind(void *av, void *bv)
1021 unsigned *a = (unsigned *) av;
1022 struct ssh_channel *b = (struct ssh_channel *) bv;
1023 if (*a < b->localid)
1025 if (*a > b->localid)
1030 static int ssh_rportcmp_ssh1(void *av, void *bv)
1032 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
1033 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
1035 if ( (i = strcmp(a->dhost, b->dhost)) != 0)
1036 return i < 0 ? -1 : +1;
1037 if (a->dport > b->dport)
1039 if (a->dport < b->dport)
1044 static int ssh_rportcmp_ssh2(void *av, void *bv)
1046 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
1047 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
1049 if ( (i = strcmp(a->shost, b->shost)) != 0)
1050 return i < 0 ? -1 : +1;
1051 if (a->sport > b->sport)
1053 if (a->sport < b->sport)
1059 * Special form of strcmp which can cope with NULL inputs. NULL is
1060 * defined to sort before even the empty string.
1062 static int nullstrcmp(const char *a, const char *b)
1064 if (a == NULL && b == NULL)
1070 return strcmp(a, b);
1073 static int ssh_portcmp(void *av, void *bv)
1075 struct ssh_portfwd *a = (struct ssh_portfwd *) av;
1076 struct ssh_portfwd *b = (struct ssh_portfwd *) bv;
1078 if (a->type > b->type)
1080 if (a->type < b->type)
1082 if (a->addressfamily > b->addressfamily)
1084 if (a->addressfamily < b->addressfamily)
1086 if ( (i = nullstrcmp(a->saddr, b->saddr)) != 0)
1087 return i < 0 ? -1 : +1;
1088 if (a->sport > b->sport)
1090 if (a->sport < b->sport)
1092 if (a->type != 'D') {
1093 if ( (i = nullstrcmp(a->daddr, b->daddr)) != 0)
1094 return i < 0 ? -1 : +1;
1095 if (a->dport > b->dport)
1097 if (a->dport < b->dport)
1103 static int alloc_channel_id(Ssh ssh)
1105 const unsigned CHANNEL_NUMBER_OFFSET = 256;
1106 unsigned low, high, mid;
1108 struct ssh_channel *c;
1111 * First-fit allocation of channel numbers: always pick the
1112 * lowest unused one. To do this, binary-search using the
1113 * counted B-tree to find the largest channel ID which is in a
1114 * contiguous sequence from the beginning. (Precisely
1115 * everything in that sequence must have ID equal to its tree
1116 * index plus CHANNEL_NUMBER_OFFSET.)
1118 tsize = count234(ssh->channels);
1122 while (high - low > 1) {
1123 mid = (high + low) / 2;
1124 c = index234(ssh->channels, mid);
1125 if (c->localid == mid + CHANNEL_NUMBER_OFFSET)
1126 low = mid; /* this one is fine */
1128 high = mid; /* this one is past it */
1131 * Now low points to either -1, or the tree index of the
1132 * largest ID in the initial sequence.
1135 unsigned i = low + 1 + CHANNEL_NUMBER_OFFSET;
1136 assert(NULL == find234(ssh->channels, &i, ssh_channelfind));
1138 return low + 1 + CHANNEL_NUMBER_OFFSET;
1141 static void c_write_stderr(int trusted, const char *buf, int len)
1144 for (i = 0; i < len; i++)
1145 if (buf[i] != '\r' && (trusted || buf[i] == '\n' || (buf[i] & 0x60)))
1146 fputc(buf[i], stderr);
1149 static void c_write(Ssh ssh, const char *buf, int len)
1151 if (flags & FLAG_STDERR)
1152 c_write_stderr(1, buf, len);
1154 from_backend(ssh->frontend, 1, buf, len);
1157 static void c_write_untrusted(Ssh ssh, const char *buf, int len)
1159 if (flags & FLAG_STDERR)
1160 c_write_stderr(0, buf, len);
1162 from_backend_untrusted(ssh->frontend, buf, len);
1165 static void c_write_str(Ssh ssh, const char *buf)
1167 c_write(ssh, buf, strlen(buf));
1170 static void ssh_free_packet(struct Packet *pkt)
1175 static struct Packet *ssh_new_packet(void)
1177 struct Packet *pkt = snew(struct Packet);
1179 pkt->body = pkt->data = NULL;
1185 static void ssh1_log_incoming_packet(Ssh ssh, struct Packet *pkt)
1188 struct logblank_t blanks[4];
1194 if (ssh->logomitdata &&
1195 (pkt->type == SSH1_SMSG_STDOUT_DATA ||
1196 pkt->type == SSH1_SMSG_STDERR_DATA ||
1197 pkt->type == SSH1_MSG_CHANNEL_DATA)) {
1198 /* "Session data" packets - omit the data string. */
1199 if (pkt->type == SSH1_MSG_CHANNEL_DATA)
1200 ssh_pkt_getuint32(pkt); /* skip channel id */
1201 blanks[nblanks].offset = pkt->savedpos + 4;
1202 blanks[nblanks].type = PKTLOG_OMIT;
1203 ssh_pkt_getstring(pkt, &str, &slen);
1205 blanks[nblanks].len = slen;
1209 log_packet(ssh->logctx, PKT_INCOMING, pkt->type,
1210 ssh1_pkt_type(pkt->type),
1211 pkt->body, pkt->length, nblanks, blanks, NULL,
1215 static void ssh1_log_outgoing_packet(Ssh ssh, struct Packet *pkt)
1218 struct logblank_t blanks[4];
1223 * For outgoing packets, pkt->length represents the length of the
1224 * whole packet starting at pkt->data (including some header), and
1225 * pkt->body refers to the point within that where the log-worthy
1226 * payload begins. However, incoming packets expect pkt->length to
1227 * represent only the payload length (that is, it's measured from
1228 * pkt->body not from pkt->data). Temporarily adjust our outgoing
1229 * packet to conform to the incoming-packet semantics, so that we
1230 * can analyse it with the ssh_pkt_get functions.
1232 pkt->length -= (pkt->body - pkt->data);
1235 if (ssh->logomitdata &&
1236 (pkt->type == SSH1_CMSG_STDIN_DATA ||
1237 pkt->type == SSH1_MSG_CHANNEL_DATA)) {
1238 /* "Session data" packets - omit the data string. */
1239 if (pkt->type == SSH1_MSG_CHANNEL_DATA)
1240 ssh_pkt_getuint32(pkt); /* skip channel id */
1241 blanks[nblanks].offset = pkt->savedpos + 4;
1242 blanks[nblanks].type = PKTLOG_OMIT;
1243 ssh_pkt_getstring(pkt, &str, &slen);
1245 blanks[nblanks].len = slen;
1250 if ((pkt->type == SSH1_CMSG_AUTH_PASSWORD ||
1251 pkt->type == SSH1_CMSG_AUTH_TIS_RESPONSE ||
1252 pkt->type == SSH1_CMSG_AUTH_CCARD_RESPONSE) &&
1253 conf_get_int(ssh->conf, CONF_logomitpass)) {
1254 /* If this is a password or similar packet, blank the password(s). */
1255 blanks[nblanks].offset = 0;
1256 blanks[nblanks].len = pkt->length;
1257 blanks[nblanks].type = PKTLOG_BLANK;
1259 } else if (pkt->type == SSH1_CMSG_X11_REQUEST_FORWARDING &&
1260 conf_get_int(ssh->conf, CONF_logomitpass)) {
1262 * If this is an X forwarding request packet, blank the fake
1265 * Note that while we blank the X authentication data here, we
1266 * don't take any special action to blank the start of an X11
1267 * channel, so using MIT-MAGIC-COOKIE-1 and actually opening
1268 * an X connection without having session blanking enabled is
1269 * likely to leak your cookie into the log.
1272 ssh_pkt_getstring(pkt, &str, &slen);
1273 blanks[nblanks].offset = pkt->savedpos;
1274 blanks[nblanks].type = PKTLOG_BLANK;
1275 ssh_pkt_getstring(pkt, &str, &slen);
1277 blanks[nblanks].len = pkt->savedpos - blanks[nblanks].offset;
1282 log_packet(ssh->logctx, PKT_OUTGOING, pkt->data[12],
1283 ssh1_pkt_type(pkt->data[12]),
1284 pkt->body, pkt->length,
1285 nblanks, blanks, NULL, 0, NULL);
1288 * Undo the above adjustment of pkt->length, to put the packet
1289 * back in the state we found it.
1291 pkt->length += (pkt->body - pkt->data);
1295 * Collect incoming data in the incoming packet buffer.
1296 * Decipher and verify the packet when it is completely read.
1297 * Drop SSH1_MSG_DEBUG and SSH1_MSG_IGNORE packets.
1298 * Update the *data and *datalen variables.
1299 * Return a Packet structure when a packet is completed.
1301 static struct Packet *ssh1_rdpkt(Ssh ssh, const unsigned char **data,
1304 struct rdpkt1_state_tag *st = &ssh->rdpkt1_state;
1306 crBegin(ssh->ssh1_rdpkt_crstate);
1308 st->pktin = ssh_new_packet();
1310 st->pktin->type = 0;
1311 st->pktin->length = 0;
1313 for (st->i = st->len = 0; st->i < 4; st->i++) {
1314 while ((*datalen) == 0)
1316 st->len = (st->len << 8) + **data;
1317 (*data)++, (*datalen)--;
1320 st->pad = 8 - (st->len % 8);
1321 st->biglen = st->len + st->pad;
1322 st->pktin->length = st->len - 5;
1324 if (st->biglen < 0) {
1325 bombout(("Extremely large packet length from server suggests"
1326 " data stream corruption"));
1327 ssh_free_packet(st->pktin);
1331 st->pktin->maxlen = st->biglen;
1332 st->pktin->data = snewn(st->biglen + APIEXTRA, unsigned char);
1334 st->to_read = st->biglen;
1335 st->p = st->pktin->data;
1336 while (st->to_read > 0) {
1337 st->chunk = st->to_read;
1338 while ((*datalen) == 0)
1340 if (st->chunk > (*datalen))
1341 st->chunk = (*datalen);
1342 memcpy(st->p, *data, st->chunk);
1344 *datalen -= st->chunk;
1346 st->to_read -= st->chunk;
1349 if (ssh->cipher && detect_attack(ssh->crcda_ctx, st->pktin->data,
1350 st->biglen, NULL)) {
1351 bombout(("Network attack (CRC compensation) detected!"));
1352 ssh_free_packet(st->pktin);
1357 ssh->cipher->decrypt(ssh->v1_cipher_ctx, st->pktin->data, st->biglen);
1359 st->realcrc = crc32_compute(st->pktin->data, st->biglen - 4);
1360 st->gotcrc = GET_32BIT(st->pktin->data + st->biglen - 4);
1361 if (st->gotcrc != st->realcrc) {
1362 bombout(("Incorrect CRC received on packet"));
1363 ssh_free_packet(st->pktin);
1367 st->pktin->body = st->pktin->data + st->pad + 1;
1369 if (ssh->v1_compressing) {
1370 unsigned char *decompblk;
1372 if (!zlib_decompress_block(ssh->sc_comp_ctx,
1373 st->pktin->body - 1, st->pktin->length + 1,
1374 &decompblk, &decomplen)) {
1375 bombout(("Zlib decompression encountered invalid data"));
1376 ssh_free_packet(st->pktin);
1380 if (st->pktin->maxlen < st->pad + decomplen) {
1381 st->pktin->maxlen = st->pad + decomplen;
1382 st->pktin->data = sresize(st->pktin->data,
1383 st->pktin->maxlen + APIEXTRA,
1385 st->pktin->body = st->pktin->data + st->pad + 1;
1388 memcpy(st->pktin->body - 1, decompblk, decomplen);
1390 st->pktin->length = decomplen - 1;
1393 st->pktin->type = st->pktin->body[-1];
1396 * Now pktin->body and pktin->length identify the semantic content
1397 * of the packet, excluding the initial type byte.
1401 ssh1_log_incoming_packet(ssh, st->pktin);
1403 st->pktin->savedpos = 0;
1405 crFinish(st->pktin);
1408 static void ssh2_log_incoming_packet(Ssh ssh, struct Packet *pkt)
1411 struct logblank_t blanks[4];
1417 if (ssh->logomitdata &&
1418 (pkt->type == SSH2_MSG_CHANNEL_DATA ||
1419 pkt->type == SSH2_MSG_CHANNEL_EXTENDED_DATA)) {
1420 /* "Session data" packets - omit the data string. */
1421 ssh_pkt_getuint32(pkt); /* skip channel id */
1422 if (pkt->type == SSH2_MSG_CHANNEL_EXTENDED_DATA)
1423 ssh_pkt_getuint32(pkt); /* skip extended data type */
1424 blanks[nblanks].offset = pkt->savedpos + 4;
1425 blanks[nblanks].type = PKTLOG_OMIT;
1426 ssh_pkt_getstring(pkt, &str, &slen);
1428 blanks[nblanks].len = slen;
1433 log_packet(ssh->logctx, PKT_INCOMING, pkt->type,
1434 ssh2_pkt_type(ssh->pkt_kctx, ssh->pkt_actx, pkt->type),
1435 pkt->body, pkt->length, nblanks, blanks, &pkt->sequence,
1439 static void ssh2_log_outgoing_packet(Ssh ssh, struct Packet *pkt)
1442 struct logblank_t blanks[4];
1447 * For outgoing packets, pkt->length represents the length of the
1448 * whole packet starting at pkt->data (including some header), and
1449 * pkt->body refers to the point within that where the log-worthy
1450 * payload begins. However, incoming packets expect pkt->length to
1451 * represent only the payload length (that is, it's measured from
1452 * pkt->body not from pkt->data). Temporarily adjust our outgoing
1453 * packet to conform to the incoming-packet semantics, so that we
1454 * can analyse it with the ssh_pkt_get functions.
1456 pkt->length -= (pkt->body - pkt->data);
1459 if (ssh->logomitdata &&
1460 (pkt->type == SSH2_MSG_CHANNEL_DATA ||
1461 pkt->type == SSH2_MSG_CHANNEL_EXTENDED_DATA)) {
1462 /* "Session data" packets - omit the data string. */
1463 ssh_pkt_getuint32(pkt); /* skip channel id */
1464 if (pkt->type == SSH2_MSG_CHANNEL_EXTENDED_DATA)
1465 ssh_pkt_getuint32(pkt); /* skip extended data type */
1466 blanks[nblanks].offset = pkt->savedpos + 4;
1467 blanks[nblanks].type = PKTLOG_OMIT;
1468 ssh_pkt_getstring(pkt, &str, &slen);
1470 blanks[nblanks].len = slen;
1475 if (pkt->type == SSH2_MSG_USERAUTH_REQUEST &&
1476 conf_get_int(ssh->conf, CONF_logomitpass)) {
1477 /* If this is a password packet, blank the password(s). */
1479 ssh_pkt_getstring(pkt, &str, &slen);
1480 ssh_pkt_getstring(pkt, &str, &slen);
1481 ssh_pkt_getstring(pkt, &str, &slen);
1482 if (slen == 8 && !memcmp(str, "password", 8)) {
1483 ssh2_pkt_getbool(pkt);
1484 /* Blank the password field. */
1485 blanks[nblanks].offset = pkt->savedpos;
1486 blanks[nblanks].type = PKTLOG_BLANK;
1487 ssh_pkt_getstring(pkt, &str, &slen);
1489 blanks[nblanks].len = pkt->savedpos - blanks[nblanks].offset;
1491 /* If there's another password field beyond it (change of
1492 * password), blank that too. */
1493 ssh_pkt_getstring(pkt, &str, &slen);
1495 blanks[nblanks-1].len =
1496 pkt->savedpos - blanks[nblanks].offset;
1499 } else if (ssh->pkt_actx == SSH2_PKTCTX_KBDINTER &&
1500 pkt->type == SSH2_MSG_USERAUTH_INFO_RESPONSE &&
1501 conf_get_int(ssh->conf, CONF_logomitpass)) {
1502 /* If this is a keyboard-interactive response packet, blank
1505 ssh_pkt_getuint32(pkt);
1506 blanks[nblanks].offset = pkt->savedpos;
1507 blanks[nblanks].type = PKTLOG_BLANK;
1509 ssh_pkt_getstring(pkt, &str, &slen);
1513 blanks[nblanks].len = pkt->savedpos - blanks[nblanks].offset;
1515 } else if (pkt->type == SSH2_MSG_CHANNEL_REQUEST &&
1516 conf_get_int(ssh->conf, CONF_logomitpass)) {
1518 * If this is an X forwarding request packet, blank the fake
1521 * Note that while we blank the X authentication data here, we
1522 * don't take any special action to blank the start of an X11
1523 * channel, so using MIT-MAGIC-COOKIE-1 and actually opening
1524 * an X connection without having session blanking enabled is
1525 * likely to leak your cookie into the log.
1528 ssh_pkt_getuint32(pkt);
1529 ssh_pkt_getstring(pkt, &str, &slen);
1530 if (slen == 7 && !memcmp(str, "x11-req", 0)) {
1531 ssh2_pkt_getbool(pkt);
1532 ssh2_pkt_getbool(pkt);
1533 ssh_pkt_getstring(pkt, &str, &slen);
1534 blanks[nblanks].offset = pkt->savedpos;
1535 blanks[nblanks].type = PKTLOG_BLANK;
1536 ssh_pkt_getstring(pkt, &str, &slen);
1538 blanks[nblanks].len = pkt->savedpos - blanks[nblanks].offset;
1544 log_packet(ssh->logctx, PKT_OUTGOING, pkt->data[5],
1545 ssh2_pkt_type(ssh->pkt_kctx, ssh->pkt_actx, pkt->data[5]),
1546 pkt->body, pkt->length, nblanks, blanks,
1547 &ssh->v2_outgoing_sequence,
1548 pkt->downstream_id, pkt->additional_log_text);
1551 * Undo the above adjustment of pkt->length, to put the packet
1552 * back in the state we found it.
1554 pkt->length += (pkt->body - pkt->data);
1557 static struct Packet *ssh2_rdpkt(Ssh ssh, const unsigned char **data,
1560 struct rdpkt2_state_tag *st = &ssh->rdpkt2_state;
1562 crBegin(ssh->ssh2_rdpkt_crstate);
1564 st->pktin = ssh_new_packet();
1566 st->pktin->type = 0;
1567 st->pktin->length = 0;
1569 st->cipherblk = ssh->sccipher->blksize;
1572 if (st->cipherblk < 8)
1574 st->maclen = ssh->scmac ? ssh->scmac->len : 0;
1576 if (ssh->sccipher && (ssh->sccipher->flags & SSH_CIPHER_IS_CBC) &&
1577 ssh->scmac && !ssh->scmac_etm) {
1579 * When dealing with a CBC-mode cipher, we want to avoid the
1580 * possibility of an attacker's tweaking the ciphertext stream
1581 * so as to cause us to feed the same block to the block
1582 * cipher more than once and thus leak information
1583 * (VU#958563). The way we do this is not to take any
1584 * decisions on the basis of anything we've decrypted until
1585 * we've verified it with a MAC. That includes the packet
1586 * length, so we just read data and check the MAC repeatedly,
1587 * and when the MAC passes, see if the length we've got is
1590 * This defence is unnecessary in OpenSSH ETM mode, because
1591 * the whole point of ETM mode is that the attacker can't
1592 * tweak the ciphertext stream at all without the MAC
1593 * detecting it before we decrypt anything.
1596 /* May as well allocate the whole lot now. */
1597 st->pktin->data = snewn(OUR_V2_PACKETLIMIT + st->maclen + APIEXTRA,
1600 /* Read an amount corresponding to the MAC. */
1601 for (st->i = 0; st->i < st->maclen; st->i++) {
1602 while ((*datalen) == 0)
1604 st->pktin->data[st->i] = *(*data)++;
1610 unsigned char seq[4];
1611 ssh->scmac->start(ssh->sc_mac_ctx);
1612 PUT_32BIT(seq, st->incoming_sequence);
1613 ssh->scmac->bytes(ssh->sc_mac_ctx, seq, 4);
1616 for (;;) { /* Once around this loop per cipher block. */
1617 /* Read another cipher-block's worth, and tack it onto the end. */
1618 for (st->i = 0; st->i < st->cipherblk; st->i++) {
1619 while ((*datalen) == 0)
1621 st->pktin->data[st->packetlen+st->maclen+st->i] = *(*data)++;
1624 /* Decrypt one more block (a little further back in the stream). */
1625 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
1626 st->pktin->data + st->packetlen,
1628 /* Feed that block to the MAC. */
1629 ssh->scmac->bytes(ssh->sc_mac_ctx,
1630 st->pktin->data + st->packetlen, st->cipherblk);
1631 st->packetlen += st->cipherblk;
1632 /* See if that gives us a valid packet. */
1633 if (ssh->scmac->verresult(ssh->sc_mac_ctx,
1634 st->pktin->data + st->packetlen) &&
1635 ((st->len = toint(GET_32BIT(st->pktin->data))) ==
1638 if (st->packetlen >= OUR_V2_PACKETLIMIT) {
1639 bombout(("No valid incoming packet found"));
1640 ssh_free_packet(st->pktin);
1644 st->pktin->maxlen = st->packetlen + st->maclen;
1645 st->pktin->data = sresize(st->pktin->data,
1646 st->pktin->maxlen + APIEXTRA,
1648 } else if (ssh->scmac && ssh->scmac_etm) {
1649 st->pktin->data = snewn(4 + APIEXTRA, unsigned char);
1652 * OpenSSH encrypt-then-MAC mode: the packet length is
1653 * unencrypted, unless the cipher supports length encryption.
1655 for (st->i = st->len = 0; st->i < 4; st->i++) {
1656 while ((*datalen) == 0)
1658 st->pktin->data[st->i] = *(*data)++;
1661 /* Cipher supports length decryption, so do it */
1662 if (ssh->sccipher && (ssh->sccipher->flags & SSH_CIPHER_SEPARATE_LENGTH)) {
1663 /* Keep the packet the same though, so the MAC passes */
1664 unsigned char len[4];
1665 memcpy(len, st->pktin->data, 4);
1666 ssh->sccipher->decrypt_length(ssh->sc_cipher_ctx, len, 4, st->incoming_sequence);
1667 st->len = toint(GET_32BIT(len));
1669 st->len = toint(GET_32BIT(st->pktin->data));
1673 * _Completely_ silly lengths should be stomped on before they
1674 * do us any more damage.
1676 if (st->len < 0 || st->len > OUR_V2_PACKETLIMIT ||
1677 st->len % st->cipherblk != 0) {
1678 bombout(("Incoming packet length field was garbled"));
1679 ssh_free_packet(st->pktin);
1684 * So now we can work out the total packet length.
1686 st->packetlen = st->len + 4;
1689 * Allocate memory for the rest of the packet.
1691 st->pktin->maxlen = st->packetlen + st->maclen;
1692 st->pktin->data = sresize(st->pktin->data,
1693 st->pktin->maxlen + APIEXTRA,
1697 * Read the remainder of the packet.
1699 for (st->i = 4; st->i < st->packetlen + st->maclen; st->i++) {
1700 while ((*datalen) == 0)
1702 st->pktin->data[st->i] = *(*data)++;
1710 && !ssh->scmac->verify(ssh->sc_mac_ctx, st->pktin->data,
1711 st->len + 4, st->incoming_sequence)) {
1712 bombout(("Incorrect MAC received on packet"));
1713 ssh_free_packet(st->pktin);
1717 /* Decrypt everything between the length field and the MAC. */
1719 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
1720 st->pktin->data + 4,
1723 st->pktin->data = snewn(st->cipherblk + APIEXTRA, unsigned char);
1726 * Acquire and decrypt the first block of the packet. This will
1727 * contain the length and padding details.
1729 for (st->i = st->len = 0; st->i < st->cipherblk; st->i++) {
1730 while ((*datalen) == 0)
1732 st->pktin->data[st->i] = *(*data)++;
1737 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
1738 st->pktin->data, st->cipherblk);
1741 * Now get the length figure.
1743 st->len = toint(GET_32BIT(st->pktin->data));
1746 * _Completely_ silly lengths should be stomped on before they
1747 * do us any more damage.
1749 if (st->len < 0 || st->len > OUR_V2_PACKETLIMIT ||
1750 (st->len + 4) % st->cipherblk != 0) {
1751 bombout(("Incoming packet was garbled on decryption"));
1752 ssh_free_packet(st->pktin);
1757 * So now we can work out the total packet length.
1759 st->packetlen = st->len + 4;
1762 * Allocate memory for the rest of the packet.
1764 st->pktin->maxlen = st->packetlen + st->maclen;
1765 st->pktin->data = sresize(st->pktin->data,
1766 st->pktin->maxlen + APIEXTRA,
1770 * Read and decrypt the remainder of the packet.
1772 for (st->i = st->cipherblk; st->i < st->packetlen + st->maclen;
1774 while ((*datalen) == 0)
1776 st->pktin->data[st->i] = *(*data)++;
1779 /* Decrypt everything _except_ the MAC. */
1781 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
1782 st->pktin->data + st->cipherblk,
1783 st->packetlen - st->cipherblk);
1789 && !ssh->scmac->verify(ssh->sc_mac_ctx, st->pktin->data,
1790 st->len + 4, st->incoming_sequence)) {
1791 bombout(("Incorrect MAC received on packet"));
1792 ssh_free_packet(st->pktin);
1796 /* Get and sanity-check the amount of random padding. */
1797 st->pad = st->pktin->data[4];
1798 if (st->pad < 4 || st->len - st->pad < 1) {
1799 bombout(("Invalid padding length on received packet"));
1800 ssh_free_packet(st->pktin);
1804 * This enables us to deduce the payload length.
1806 st->payload = st->len - st->pad - 1;
1808 st->pktin->length = st->payload + 5;
1809 st->pktin->encrypted_len = st->packetlen;
1811 st->pktin->sequence = st->incoming_sequence++;
1813 st->pktin->length = st->packetlen - st->pad;
1814 assert(st->pktin->length >= 0);
1817 * Decompress packet payload.
1820 unsigned char *newpayload;
1823 ssh->sccomp->decompress(ssh->sc_comp_ctx,
1824 st->pktin->data + 5, st->pktin->length - 5,
1825 &newpayload, &newlen)) {
1826 if (st->pktin->maxlen < newlen + 5) {
1827 st->pktin->maxlen = newlen + 5;
1828 st->pktin->data = sresize(st->pktin->data,
1829 st->pktin->maxlen + APIEXTRA,
1832 st->pktin->length = 5 + newlen;
1833 memcpy(st->pktin->data + 5, newpayload, newlen);
1839 * RFC 4253 doesn't explicitly say that completely empty packets
1840 * with no type byte are forbidden, so treat them as deserving
1841 * an SSH_MSG_UNIMPLEMENTED.
1843 if (st->pktin->length <= 5) { /* == 5 we hope, but robustness */
1844 ssh2_msg_something_unimplemented(ssh, st->pktin);
1848 * pktin->body and pktin->length should identify the semantic
1849 * content of the packet, excluding the initial type byte.
1851 st->pktin->type = st->pktin->data[5];
1852 st->pktin->body = st->pktin->data + 6;
1853 st->pktin->length -= 6;
1854 assert(st->pktin->length >= 0); /* one last double-check */
1857 ssh2_log_incoming_packet(ssh, st->pktin);
1859 st->pktin->savedpos = 0;
1861 crFinish(st->pktin);
1864 static struct Packet *ssh2_bare_connection_rdpkt(Ssh ssh,
1865 const unsigned char **data,
1868 struct rdpkt2_bare_state_tag *st = &ssh->rdpkt2_bare_state;
1870 crBegin(ssh->ssh2_bare_rdpkt_crstate);
1873 * Read the packet length field.
1875 for (st->i = 0; st->i < 4; st->i++) {
1876 while ((*datalen) == 0)
1878 st->length[st->i] = *(*data)++;
1882 st->packetlen = toint(GET_32BIT_MSB_FIRST(st->length));
1883 if (st->packetlen <= 0 || st->packetlen >= OUR_V2_PACKETLIMIT) {
1884 bombout(("Invalid packet length received"));
1888 st->pktin = ssh_new_packet();
1889 st->pktin->data = snewn(st->packetlen, unsigned char);
1891 st->pktin->encrypted_len = st->packetlen;
1893 st->pktin->sequence = st->incoming_sequence++;
1896 * Read the remainder of the packet.
1898 for (st->i = 0; st->i < st->packetlen; st->i++) {
1899 while ((*datalen) == 0)
1901 st->pktin->data[st->i] = *(*data)++;
1906 * pktin->body and pktin->length should identify the semantic
1907 * content of the packet, excluding the initial type byte.
1909 st->pktin->type = st->pktin->data[0];
1910 st->pktin->body = st->pktin->data + 1;
1911 st->pktin->length = st->packetlen - 1;
1914 * Log incoming packet, possibly omitting sensitive fields.
1917 ssh2_log_incoming_packet(ssh, st->pktin);
1919 st->pktin->savedpos = 0;
1921 crFinish(st->pktin);
1924 static int s_wrpkt_prepare(Ssh ssh, struct Packet *pkt, int *offset_p)
1926 int pad, biglen, i, pktoffs;
1930 * XXX various versions of SC (including 8.8.4) screw up the
1931 * register allocation in this function and use the same register
1932 * (D6) for len and as a temporary, with predictable results. The
1933 * following sledgehammer prevents this.
1940 ssh1_log_outgoing_packet(ssh, pkt);
1942 if (ssh->v1_compressing) {
1943 unsigned char *compblk;
1945 zlib_compress_block(ssh->cs_comp_ctx,
1946 pkt->data + 12, pkt->length - 12,
1947 &compblk, &complen);
1948 ssh_pkt_ensure(pkt, complen + 2); /* just in case it's got bigger */
1949 memcpy(pkt->data + 12, compblk, complen);
1951 pkt->length = complen + 12;
1954 ssh_pkt_ensure(pkt, pkt->length + 4); /* space for CRC */
1956 len = pkt->length - 4 - 8; /* len(type+data+CRC) */
1957 pad = 8 - (len % 8);
1959 biglen = len + pad; /* len(padding+type+data+CRC) */
1961 for (i = pktoffs; i < 4+8; i++)
1962 pkt->data[i] = random_byte();
1963 crc = crc32_compute(pkt->data + pktoffs + 4, biglen - 4); /* all ex len */
1964 PUT_32BIT(pkt->data + pktoffs + 4 + biglen - 4, crc);
1965 PUT_32BIT(pkt->data + pktoffs, len);
1968 ssh->cipher->encrypt(ssh->v1_cipher_ctx,
1969 pkt->data + pktoffs + 4, biglen);
1971 if (offset_p) *offset_p = pktoffs;
1972 return biglen + 4; /* len(length+padding+type+data+CRC) */
1975 static int s_write(Ssh ssh, void *data, int len)
1978 log_packet(ssh->logctx, PKT_OUTGOING, -1, NULL, data, len,
1979 0, NULL, NULL, 0, NULL);
1982 return sk_write(ssh->s, (char *)data, len);
1985 static void s_wrpkt(Ssh ssh, struct Packet *pkt)
1987 int len, backlog, offset;
1988 len = s_wrpkt_prepare(ssh, pkt, &offset);
1989 backlog = s_write(ssh, pkt->data + offset, len);
1990 if (backlog > SSH_MAX_BACKLOG)
1991 ssh_throttle_all(ssh, 1, backlog);
1992 ssh_free_packet(pkt);
1995 static void s_wrpkt_defer(Ssh ssh, struct Packet *pkt)
1998 len = s_wrpkt_prepare(ssh, pkt, &offset);
1999 if (ssh->deferred_len + len > ssh->deferred_size) {
2000 ssh->deferred_size = ssh->deferred_len + len + 128;
2001 ssh->deferred_send_data = sresize(ssh->deferred_send_data,
2005 memcpy(ssh->deferred_send_data + ssh->deferred_len,
2006 pkt->data + offset, len);
2007 ssh->deferred_len += len;
2008 ssh_free_packet(pkt);
2012 * Construct a SSH-1 packet with the specified contents.
2013 * (This all-at-once interface used to be the only one, but now SSH-1
2014 * packets can also be constructed incrementally.)
2016 static struct Packet *construct_packet(Ssh ssh, int pkttype, va_list ap)
2022 pkt = ssh1_pkt_init(pkttype);
2024 while ((argtype = va_arg(ap, int)) != PKT_END) {
2025 unsigned char *argp, argchar;
2027 unsigned long argint;
2030 /* Actual fields in the packet */
2032 argint = va_arg(ap, int);
2033 ssh_pkt_adduint32(pkt, argint);
2036 argchar = (unsigned char) va_arg(ap, int);
2037 ssh_pkt_addbyte(pkt, argchar);
2040 argp = va_arg(ap, unsigned char *);
2041 arglen = va_arg(ap, int);
2042 ssh_pkt_adddata(pkt, argp, arglen);
2045 sargp = va_arg(ap, char *);
2046 ssh_pkt_addstring(pkt, sargp);
2049 bn = va_arg(ap, Bignum);
2050 ssh1_pkt_addmp(pkt, bn);
2058 static void send_packet(Ssh ssh, int pkttype, ...)
2062 va_start(ap, pkttype);
2063 pkt = construct_packet(ssh, pkttype, ap);
2068 static void defer_packet(Ssh ssh, int pkttype, ...)
2072 va_start(ap, pkttype);
2073 pkt = construct_packet(ssh, pkttype, ap);
2075 s_wrpkt_defer(ssh, pkt);
2078 static int ssh_versioncmp(const char *a, const char *b)
2081 unsigned long av, bv;
2083 av = strtoul(a, &ae, 10);
2084 bv = strtoul(b, &be, 10);
2086 return (av < bv ? -1 : +1);
2091 av = strtoul(ae, &ae, 10);
2092 bv = strtoul(be, &be, 10);
2094 return (av < bv ? -1 : +1);
2099 * Utility routines for putting an SSH-protocol `string' and
2100 * `uint32' into a hash state.
2102 static void hash_string(const struct ssh_hash *h, void *s, void *str, int len)
2104 unsigned char lenblk[4];
2105 PUT_32BIT(lenblk, len);
2106 h->bytes(s, lenblk, 4);
2107 h->bytes(s, str, len);
2110 static void hash_uint32(const struct ssh_hash *h, void *s, unsigned i)
2112 unsigned char intblk[4];
2113 PUT_32BIT(intblk, i);
2114 h->bytes(s, intblk, 4);
2118 * Packet construction functions. Mostly shared between SSH-1 and SSH-2.
2120 static void ssh_pkt_ensure(struct Packet *pkt, int length)
2122 if (pkt->maxlen < length) {
2123 unsigned char *body = pkt->body;
2124 int offset = body ? body - pkt->data : 0;
2125 pkt->maxlen = length + 256;
2126 pkt->data = sresize(pkt->data, pkt->maxlen + APIEXTRA, unsigned char);
2127 if (body) pkt->body = pkt->data + offset;
2130 static void ssh_pkt_adddata(struct Packet *pkt, const void *data, int len)
2133 ssh_pkt_ensure(pkt, pkt->length);
2134 memcpy(pkt->data + pkt->length - len, data, len);
2136 static void ssh_pkt_addbyte(struct Packet *pkt, unsigned char byte)
2138 ssh_pkt_adddata(pkt, &byte, 1);
2140 static void ssh2_pkt_addbool(struct Packet *pkt, unsigned char value)
2142 ssh_pkt_adddata(pkt, &value, 1);
2144 static void ssh_pkt_adduint32(struct Packet *pkt, unsigned long value)
2147 PUT_32BIT(x, value);
2148 ssh_pkt_adddata(pkt, x, 4);
2150 static void ssh_pkt_addstring_start(struct Packet *pkt)
2152 ssh_pkt_adduint32(pkt, 0);
2153 pkt->savedpos = pkt->length;
2155 static void ssh_pkt_addstring_data(struct Packet *pkt, const char *data,
2158 ssh_pkt_adddata(pkt, data, len);
2159 PUT_32BIT(pkt->data + pkt->savedpos - 4, pkt->length - pkt->savedpos);
2161 static void ssh_pkt_addstring_str(struct Packet *pkt, const char *data)
2163 ssh_pkt_addstring_data(pkt, data, strlen(data));
2165 static void ssh_pkt_addstring(struct Packet *pkt, const char *data)
2167 ssh_pkt_addstring_start(pkt);
2168 ssh_pkt_addstring_str(pkt, data);
2170 static void ssh1_pkt_addmp(struct Packet *pkt, Bignum b)
2172 int len = ssh1_bignum_length(b);
2173 unsigned char *data = snewn(len, unsigned char);
2174 (void) ssh1_write_bignum(data, b);
2175 ssh_pkt_adddata(pkt, data, len);
2178 static unsigned char *ssh2_mpint_fmt(Bignum b, int *len)
2181 int i, n = (bignum_bitcount(b) + 7) / 8;
2182 p = snewn(n + 1, unsigned char);
2184 for (i = 1; i <= n; i++)
2185 p[i] = bignum_byte(b, n - i);
2187 while (i <= n && p[i] == 0 && (p[i + 1] & 0x80) == 0)
2189 memmove(p, p + i, n + 1 - i);
2193 static void ssh2_pkt_addmp(struct Packet *pkt, Bignum b)
2197 p = ssh2_mpint_fmt(b, &len);
2198 ssh_pkt_addstring_start(pkt);
2199 ssh_pkt_addstring_data(pkt, (char *)p, len);
2203 static struct Packet *ssh1_pkt_init(int pkt_type)
2205 struct Packet *pkt = ssh_new_packet();
2206 pkt->length = 4 + 8; /* space for length + max padding */
2207 ssh_pkt_addbyte(pkt, pkt_type);
2208 pkt->body = pkt->data + pkt->length;
2209 pkt->type = pkt_type;
2210 pkt->downstream_id = 0;
2211 pkt->additional_log_text = NULL;
2215 /* For legacy code (SSH-1 and -2 packet construction used to be separate) */
2216 #define ssh2_pkt_ensure(pkt, length) ssh_pkt_ensure(pkt, length)
2217 #define ssh2_pkt_adddata(pkt, data, len) ssh_pkt_adddata(pkt, data, len)
2218 #define ssh2_pkt_addbyte(pkt, byte) ssh_pkt_addbyte(pkt, byte)
2219 #define ssh2_pkt_adduint32(pkt, value) ssh_pkt_adduint32(pkt, value)
2220 #define ssh2_pkt_addstring_start(pkt) ssh_pkt_addstring_start(pkt)
2221 #define ssh2_pkt_addstring_str(pkt, data) ssh_pkt_addstring_str(pkt, data)
2222 #define ssh2_pkt_addstring_data(pkt, data, len) ssh_pkt_addstring_data(pkt, data, len)
2223 #define ssh2_pkt_addstring(pkt, data) ssh_pkt_addstring(pkt, data)
2225 static struct Packet *ssh2_pkt_init(int pkt_type)
2227 struct Packet *pkt = ssh_new_packet();
2228 pkt->length = 5; /* space for packet length + padding length */
2230 pkt->type = pkt_type;
2231 ssh_pkt_addbyte(pkt, (unsigned char) pkt_type);
2232 pkt->body = pkt->data + pkt->length; /* after packet type */
2233 pkt->downstream_id = 0;
2234 pkt->additional_log_text = NULL;
2239 * Construct an SSH-2 final-form packet: compress it, encrypt it,
2240 * put the MAC on it. Final packet, ready to be sent, is stored in
2241 * pkt->data. Total length is returned.
2243 static int ssh2_pkt_construct(Ssh ssh, struct Packet *pkt)
2245 int cipherblk, maclen, padding, unencrypted_prefix, i;
2248 ssh2_log_outgoing_packet(ssh, pkt);
2250 if (ssh->bare_connection) {
2252 * Trivial packet construction for the bare connection
2255 PUT_32BIT(pkt->data + 1, pkt->length - 5);
2256 pkt->body = pkt->data + 1;
2257 ssh->v2_outgoing_sequence++; /* only for diagnostics, really */
2258 return pkt->length - 1;
2262 * Compress packet payload.
2265 unsigned char *newpayload;
2268 ssh->cscomp->compress(ssh->cs_comp_ctx, pkt->data + 5,
2270 &newpayload, &newlen)) {
2272 ssh2_pkt_adddata(pkt, newpayload, newlen);
2278 * Add padding. At least four bytes, and must also bring total
2279 * length (minus MAC) up to a multiple of the block size.
2280 * If pkt->forcepad is set, make sure the packet is at least that size
2283 cipherblk = ssh->cscipher ? ssh->cscipher->blksize : 8; /* block size */
2284 cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */
2286 unencrypted_prefix = (ssh->csmac && ssh->csmac_etm) ? 4 : 0;
2287 if (pkt->length + padding < pkt->forcepad)
2288 padding = pkt->forcepad - pkt->length;
2290 (cipherblk - (pkt->length - unencrypted_prefix + padding) % cipherblk)
2292 assert(padding <= 255);
2293 maclen = ssh->csmac ? ssh->csmac->len : 0;
2294 ssh2_pkt_ensure(pkt, pkt->length + padding + maclen);
2295 pkt->data[4] = padding;
2296 for (i = 0; i < padding; i++)
2297 pkt->data[pkt->length + i] = random_byte();
2298 PUT_32BIT(pkt->data, pkt->length + padding - 4);
2300 /* Encrypt length if the scheme requires it */
2301 if (ssh->cscipher && (ssh->cscipher->flags & SSH_CIPHER_SEPARATE_LENGTH)) {
2302 ssh->cscipher->encrypt_length(ssh->cs_cipher_ctx, pkt->data, 4,
2303 ssh->v2_outgoing_sequence);
2306 if (ssh->csmac && ssh->csmac_etm) {
2308 * OpenSSH-defined encrypt-then-MAC protocol.
2311 ssh->cscipher->encrypt(ssh->cs_cipher_ctx,
2312 pkt->data + 4, pkt->length + padding - 4);
2313 ssh->csmac->generate(ssh->cs_mac_ctx, pkt->data,
2314 pkt->length + padding,
2315 ssh->v2_outgoing_sequence);
2318 * SSH-2 standard protocol.
2321 ssh->csmac->generate(ssh->cs_mac_ctx, pkt->data,
2322 pkt->length + padding,
2323 ssh->v2_outgoing_sequence);
2325 ssh->cscipher->encrypt(ssh->cs_cipher_ctx,
2326 pkt->data, pkt->length + padding);
2329 ssh->v2_outgoing_sequence++; /* whether or not we MACed */
2330 pkt->encrypted_len = pkt->length + padding;
2332 /* Ready-to-send packet starts at pkt->data. We return length. */
2333 pkt->body = pkt->data;
2334 return pkt->length + padding + maclen;
2338 * Routines called from the main SSH code to send packets. There
2339 * are quite a few of these, because we have two separate
2340 * mechanisms for delaying the sending of packets:
2342 * - In order to send an IGNORE message and a password message in
2343 * a single fixed-length blob, we require the ability to
2344 * concatenate the encrypted forms of those two packets _into_ a
2345 * single blob and then pass it to our <network.h> transport
2346 * layer in one go. Hence, there's a deferment mechanism which
2347 * works after packet encryption.
2349 * - In order to avoid sending any connection-layer messages
2350 * during repeat key exchange, we have to queue up any such
2351 * outgoing messages _before_ they are encrypted (and in
2352 * particular before they're allocated sequence numbers), and
2353 * then send them once we've finished.
2355 * I call these mechanisms `defer' and `queue' respectively, so as
2356 * to distinguish them reasonably easily.
2358 * The functions send_noqueue() and defer_noqueue() free the packet
2359 * structure they are passed. Every outgoing packet goes through
2360 * precisely one of these functions in its life; packets passed to
2361 * ssh2_pkt_send() or ssh2_pkt_defer() either go straight to one of
2362 * these or get queued, and then when the queue is later emptied
2363 * the packets are all passed to defer_noqueue().
2365 * When using a CBC-mode cipher, it's necessary to ensure that an
2366 * attacker can't provide data to be encrypted using an IV that they
2367 * know. We ensure this by prefixing each packet that might contain
2368 * user data with an SSH_MSG_IGNORE. This is done using the deferral
2369 * mechanism, so in this case send_noqueue() ends up redirecting to
2370 * defer_noqueue(). If you don't like this inefficiency, don't use
2374 static void ssh2_pkt_defer_noqueue(Ssh, struct Packet *, int);
2375 static void ssh_pkt_defersend(Ssh);
2378 * Send an SSH-2 packet immediately, without queuing or deferring.
2380 static void ssh2_pkt_send_noqueue(Ssh ssh, struct Packet *pkt)
2384 if (ssh->cscipher != NULL && (ssh->cscipher->flags & SSH_CIPHER_IS_CBC)) {
2385 /* We need to send two packets, so use the deferral mechanism. */
2386 ssh2_pkt_defer_noqueue(ssh, pkt, FALSE);
2387 ssh_pkt_defersend(ssh);
2390 len = ssh2_pkt_construct(ssh, pkt);
2391 backlog = s_write(ssh, pkt->body, len);
2392 if (backlog > SSH_MAX_BACKLOG)
2393 ssh_throttle_all(ssh, 1, backlog);
2395 ssh->outgoing_data_size += pkt->encrypted_len;
2396 if (!ssh->kex_in_progress &&
2397 !ssh->bare_connection &&
2398 ssh->max_data_size != 0 &&
2399 ssh->outgoing_data_size > ssh->max_data_size)
2400 do_ssh2_transport(ssh, "too much data sent", -1, NULL);
2402 ssh_free_packet(pkt);
2406 * Defer an SSH-2 packet.
2408 static void ssh2_pkt_defer_noqueue(Ssh ssh, struct Packet *pkt, int noignore)
2411 if (ssh->cscipher != NULL && (ssh->cscipher->flags & SSH_CIPHER_IS_CBC) &&
2412 ssh->deferred_len == 0 && !noignore &&
2413 !(ssh->remote_bugs & BUG_CHOKES_ON_SSH2_IGNORE)) {
2415 * Interpose an SSH_MSG_IGNORE to ensure that user data don't
2416 * get encrypted with a known IV.
2418 struct Packet *ipkt = ssh2_pkt_init(SSH2_MSG_IGNORE);
2419 ssh2_pkt_addstring_start(ipkt);
2420 ssh2_pkt_defer_noqueue(ssh, ipkt, TRUE);
2422 len = ssh2_pkt_construct(ssh, pkt);
2423 if (ssh->deferred_len + len > ssh->deferred_size) {
2424 ssh->deferred_size = ssh->deferred_len + len + 128;
2425 ssh->deferred_send_data = sresize(ssh->deferred_send_data,
2429 memcpy(ssh->deferred_send_data + ssh->deferred_len, pkt->body, len);
2430 ssh->deferred_len += len;
2431 ssh->deferred_data_size += pkt->encrypted_len;
2432 ssh_free_packet(pkt);
2436 * Queue an SSH-2 packet.
2438 static void ssh2_pkt_queue(Ssh ssh, struct Packet *pkt)
2440 assert(ssh->queueing);
2442 if (ssh->queuelen >= ssh->queuesize) {
2443 ssh->queuesize = ssh->queuelen + 32;
2444 ssh->queue = sresize(ssh->queue, ssh->queuesize, struct Packet *);
2447 ssh->queue[ssh->queuelen++] = pkt;
2451 * Either queue or send a packet, depending on whether queueing is
2454 static void ssh2_pkt_send(Ssh ssh, struct Packet *pkt)
2457 ssh2_pkt_queue(ssh, pkt);
2459 ssh2_pkt_send_noqueue(ssh, pkt);
2463 * Either queue or defer a packet, depending on whether queueing is
2466 static void ssh2_pkt_defer(Ssh ssh, struct Packet *pkt)
2469 ssh2_pkt_queue(ssh, pkt);
2471 ssh2_pkt_defer_noqueue(ssh, pkt, FALSE);
2475 * Send the whole deferred data block constructed by
2476 * ssh2_pkt_defer() or SSH-1's defer_packet().
2478 * The expected use of the defer mechanism is that you call
2479 * ssh2_pkt_defer() a few times, then call ssh_pkt_defersend(). If
2480 * not currently queueing, this simply sets up deferred_send_data
2481 * and then sends it. If we _are_ currently queueing, the calls to
2482 * ssh2_pkt_defer() put the deferred packets on to the queue
2483 * instead, and therefore ssh_pkt_defersend() has no deferred data
2484 * to send. Hence, there's no need to make it conditional on
2487 static void ssh_pkt_defersend(Ssh ssh)
2490 backlog = s_write(ssh, ssh->deferred_send_data, ssh->deferred_len);
2491 ssh->deferred_len = ssh->deferred_size = 0;
2492 sfree(ssh->deferred_send_data);
2493 ssh->deferred_send_data = NULL;
2494 if (backlog > SSH_MAX_BACKLOG)
2495 ssh_throttle_all(ssh, 1, backlog);
2497 ssh->outgoing_data_size += ssh->deferred_data_size;
2498 if (!ssh->kex_in_progress &&
2499 !ssh->bare_connection &&
2500 ssh->max_data_size != 0 &&
2501 ssh->outgoing_data_size > ssh->max_data_size)
2502 do_ssh2_transport(ssh, "too much data sent", -1, NULL);
2503 ssh->deferred_data_size = 0;
2507 * Send a packet whose length needs to be disguised (typically
2508 * passwords or keyboard-interactive responses).
2510 static void ssh2_pkt_send_with_padding(Ssh ssh, struct Packet *pkt,
2516 * The simplest way to do this is to adjust the
2517 * variable-length padding field in the outgoing packet.
2519 * Currently compiled out, because some Cisco SSH servers
2520 * don't like excessively padded packets (bah, why's it
2523 pkt->forcepad = padsize;
2524 ssh2_pkt_send(ssh, pkt);
2529 * If we can't do that, however, an alternative approach is
2530 * to use the pkt_defer mechanism to bundle the packet
2531 * tightly together with an SSH_MSG_IGNORE such that their
2532 * combined length is a constant. So first we construct the
2533 * final form of this packet and defer its sending.
2535 ssh2_pkt_defer(ssh, pkt);
2538 * Now construct an SSH_MSG_IGNORE which includes a string
2539 * that's an exact multiple of the cipher block size. (If
2540 * the cipher is NULL so that the block size is
2541 * unavailable, we don't do this trick at all, because we
2542 * gain nothing by it.)
2544 if (ssh->cscipher &&
2545 !(ssh->remote_bugs & BUG_CHOKES_ON_SSH2_IGNORE)) {
2548 stringlen = (256 - ssh->deferred_len);
2549 stringlen += ssh->cscipher->blksize - 1;
2550 stringlen -= (stringlen % ssh->cscipher->blksize);
2553 * Temporarily disable actual compression, so we
2554 * can guarantee to get this string exactly the
2555 * length we want it. The compression-disabling
2556 * routine should return an integer indicating how
2557 * many bytes we should adjust our string length
2561 ssh->cscomp->disable_compression(ssh->cs_comp_ctx);
2563 pkt = ssh2_pkt_init(SSH2_MSG_IGNORE);
2564 ssh2_pkt_addstring_start(pkt);
2565 for (i = 0; i < stringlen; i++) {
2566 char c = (char) random_byte();
2567 ssh2_pkt_addstring_data(pkt, &c, 1);
2569 ssh2_pkt_defer(ssh, pkt);
2571 ssh_pkt_defersend(ssh);
2576 * Send all queued SSH-2 packets. We send them by means of
2577 * ssh2_pkt_defer_noqueue(), in case they included a pair of
2578 * packets that needed to be lumped together.
2580 static void ssh2_pkt_queuesend(Ssh ssh)
2584 assert(!ssh->queueing);
2586 for (i = 0; i < ssh->queuelen; i++)
2587 ssh2_pkt_defer_noqueue(ssh, ssh->queue[i], FALSE);
2590 ssh_pkt_defersend(ssh);
2594 void bndebug(char *string, Bignum b)
2598 p = ssh2_mpint_fmt(b, &len);
2599 debug(("%s", string));
2600 for (i = 0; i < len; i++)
2601 debug((" %02x", p[i]));
2607 static void hash_mpint(const struct ssh_hash *h, void *s, Bignum b)
2611 p = ssh2_mpint_fmt(b, &len);
2612 hash_string(h, s, p, len);
2617 * Packet decode functions for both SSH-1 and SSH-2.
2619 static unsigned long ssh_pkt_getuint32(struct Packet *pkt)
2621 unsigned long value;
2622 if (pkt->length - pkt->savedpos < 4)
2623 return 0; /* arrgh, no way to decline (FIXME?) */
2624 value = GET_32BIT(pkt->body + pkt->savedpos);
2628 static int ssh2_pkt_getbool(struct Packet *pkt)
2630 unsigned long value;
2631 if (pkt->length - pkt->savedpos < 1)
2632 return 0; /* arrgh, no way to decline (FIXME?) */
2633 value = pkt->body[pkt->savedpos] != 0;
2637 static void ssh_pkt_getstring(struct Packet *pkt, char **p, int *length)
2642 if (pkt->length - pkt->savedpos < 4)
2644 len = toint(GET_32BIT(pkt->body + pkt->savedpos));
2649 if (pkt->length - pkt->savedpos < *length)
2651 *p = (char *)(pkt->body + pkt->savedpos);
2652 pkt->savedpos += *length;
2654 static void *ssh_pkt_getdata(struct Packet *pkt, int length)
2656 if (pkt->length - pkt->savedpos < length)
2658 pkt->savedpos += length;
2659 return pkt->body + (pkt->savedpos - length);
2661 static int ssh1_pkt_getrsakey(struct Packet *pkt, struct RSAKey *key,
2662 const unsigned char **keystr)
2666 j = makekey(pkt->body + pkt->savedpos,
2667 pkt->length - pkt->savedpos,
2674 assert(pkt->savedpos < pkt->length);
2678 static Bignum ssh1_pkt_getmp(struct Packet *pkt)
2683 j = ssh1_read_bignum(pkt->body + pkt->savedpos,
2684 pkt->length - pkt->savedpos, &b);
2692 static Bignum ssh2_pkt_getmp(struct Packet *pkt)
2698 ssh_pkt_getstring(pkt, &p, &length);
2703 b = bignum_from_bytes((unsigned char *)p, length);
2708 * Helper function to add an SSH-2 signature blob to a packet.
2709 * Expects to be shown the public key blob as well as the signature
2710 * blob. Normally works just like ssh2_pkt_addstring, but will
2711 * fiddle with the signature packet if necessary for
2712 * BUG_SSH2_RSA_PADDING.
2714 static void ssh2_add_sigblob(Ssh ssh, struct Packet *pkt,
2715 void *pkblob_v, int pkblob_len,
2716 void *sigblob_v, int sigblob_len)
2718 unsigned char *pkblob = (unsigned char *)pkblob_v;
2719 unsigned char *sigblob = (unsigned char *)sigblob_v;
2721 /* dmemdump(pkblob, pkblob_len); */
2722 /* dmemdump(sigblob, sigblob_len); */
2725 * See if this is in fact an ssh-rsa signature and a buggy
2726 * server; otherwise we can just do this the easy way.
2728 if ((ssh->remote_bugs & BUG_SSH2_RSA_PADDING) && pkblob_len > 4+7+4 &&
2729 (GET_32BIT(pkblob) == 7 && !memcmp(pkblob+4, "ssh-rsa", 7))) {
2730 int pos, len, siglen;
2733 * Find the byte length of the modulus.
2736 pos = 4+7; /* skip over "ssh-rsa" */
2737 len = toint(GET_32BIT(pkblob+pos)); /* get length of exponent */
2738 if (len < 0 || len > pkblob_len - pos - 4)
2740 pos += 4 + len; /* skip over exponent */
2741 if (pkblob_len - pos < 4)
2743 len = toint(GET_32BIT(pkblob+pos)); /* find length of modulus */
2744 if (len < 0 || len > pkblob_len - pos - 4)
2746 pos += 4; /* find modulus itself */
2747 while (len > 0 && pkblob[pos] == 0)
2749 /* debug(("modulus length is %d\n", len)); */
2752 * Now find the signature integer.
2754 pos = 4+7; /* skip over "ssh-rsa" */
2755 if (sigblob_len < pos+4)
2757 siglen = toint(GET_32BIT(sigblob+pos));
2758 if (siglen != sigblob_len - pos - 4)
2760 /* debug(("signature length is %d\n", siglen)); */
2762 if (len != siglen) {
2763 unsigned char newlen[4];
2764 ssh2_pkt_addstring_start(pkt);
2765 ssh2_pkt_addstring_data(pkt, (char *)sigblob, pos);
2766 /* dmemdump(sigblob, pos); */
2767 pos += 4; /* point to start of actual sig */
2768 PUT_32BIT(newlen, len);
2769 ssh2_pkt_addstring_data(pkt, (char *)newlen, 4);
2770 /* dmemdump(newlen, 4); */
2772 while (len-- > siglen) {
2773 ssh2_pkt_addstring_data(pkt, (char *)newlen, 1);
2774 /* dmemdump(newlen, 1); */
2776 ssh2_pkt_addstring_data(pkt, (char *)(sigblob+pos), siglen);
2777 /* dmemdump(sigblob+pos, siglen); */
2781 /* Otherwise fall through and do it the easy way. We also come
2782 * here as a fallback if we discover above that the key blob
2783 * is misformatted in some way. */
2787 ssh2_pkt_addstring_start(pkt);
2788 ssh2_pkt_addstring_data(pkt, (char *)sigblob, sigblob_len);
2792 * Examine the remote side's version string and compare it against
2793 * a list of known buggy implementations.
2795 static void ssh_detect_bugs(Ssh ssh, char *vstring)
2797 char *imp; /* pointer to implementation part */
2799 imp += strcspn(imp, "-");
2801 imp += strcspn(imp, "-");
2804 ssh->remote_bugs = 0;
2807 * General notes on server version strings:
2808 * - Not all servers reporting "Cisco-1.25" have all the bugs listed
2809 * here -- in particular, we've heard of one that's perfectly happy
2810 * with SSH1_MSG_IGNOREs -- but this string never seems to change,
2811 * so we can't distinguish them.
2813 if (conf_get_int(ssh->conf, CONF_sshbug_ignore1) == FORCE_ON ||
2814 (conf_get_int(ssh->conf, CONF_sshbug_ignore1) == AUTO &&
2815 (!strcmp(imp, "1.2.18") || !strcmp(imp, "1.2.19") ||
2816 !strcmp(imp, "1.2.20") || !strcmp(imp, "1.2.21") ||
2817 !strcmp(imp, "1.2.22") || !strcmp(imp, "Cisco-1.25") ||
2818 !strcmp(imp, "OSU_1.4alpha3") || !strcmp(imp, "OSU_1.5alpha4")))) {
2820 * These versions don't support SSH1_MSG_IGNORE, so we have
2821 * to use a different defence against password length
2824 ssh->remote_bugs |= BUG_CHOKES_ON_SSH1_IGNORE;
2825 logevent("We believe remote version has SSH-1 ignore bug");
2828 if (conf_get_int(ssh->conf, CONF_sshbug_plainpw1) == FORCE_ON ||
2829 (conf_get_int(ssh->conf, CONF_sshbug_plainpw1) == AUTO &&
2830 (!strcmp(imp, "Cisco-1.25") || !strcmp(imp, "OSU_1.4alpha3")))) {
2832 * These versions need a plain password sent; they can't
2833 * handle having a null and a random length of data after
2836 ssh->remote_bugs |= BUG_NEEDS_SSH1_PLAIN_PASSWORD;
2837 logevent("We believe remote version needs a plain SSH-1 password");
2840 if (conf_get_int(ssh->conf, CONF_sshbug_rsa1) == FORCE_ON ||
2841 (conf_get_int(ssh->conf, CONF_sshbug_rsa1) == AUTO &&
2842 (!strcmp(imp, "Cisco-1.25")))) {
2844 * These versions apparently have no clue whatever about
2845 * RSA authentication and will panic and die if they see
2846 * an AUTH_RSA message.
2848 ssh->remote_bugs |= BUG_CHOKES_ON_RSA;
2849 logevent("We believe remote version can't handle SSH-1 RSA authentication");
2852 if (conf_get_int(ssh->conf, CONF_sshbug_hmac2) == FORCE_ON ||
2853 (conf_get_int(ssh->conf, CONF_sshbug_hmac2) == AUTO &&
2854 !wc_match("* VShell", imp) &&
2855 (wc_match("2.1.0*", imp) || wc_match("2.0.*", imp) ||
2856 wc_match("2.2.0*", imp) || wc_match("2.3.0*", imp) ||
2857 wc_match("2.1 *", imp)))) {
2859 * These versions have the HMAC bug.
2861 ssh->remote_bugs |= BUG_SSH2_HMAC;
2862 logevent("We believe remote version has SSH-2 HMAC bug");
2865 if (conf_get_int(ssh->conf, CONF_sshbug_derivekey2) == FORCE_ON ||
2866 (conf_get_int(ssh->conf, CONF_sshbug_derivekey2) == AUTO &&
2867 !wc_match("* VShell", imp) &&
2868 (wc_match("2.0.0*", imp) || wc_match("2.0.10*", imp) ))) {
2870 * These versions have the key-derivation bug (failing to
2871 * include the literal shared secret in the hashes that
2872 * generate the keys).
2874 ssh->remote_bugs |= BUG_SSH2_DERIVEKEY;
2875 logevent("We believe remote version has SSH-2 key-derivation bug");
2878 if (conf_get_int(ssh->conf, CONF_sshbug_rsapad2) == FORCE_ON ||
2879 (conf_get_int(ssh->conf, CONF_sshbug_rsapad2) == AUTO &&
2880 (wc_match("OpenSSH_2.[5-9]*", imp) ||
2881 wc_match("OpenSSH_3.[0-2]*", imp) ||
2882 wc_match("mod_sftp/0.[0-8]*", imp) ||
2883 wc_match("mod_sftp/0.9.[0-8]", imp)))) {
2885 * These versions have the SSH-2 RSA padding bug.
2887 ssh->remote_bugs |= BUG_SSH2_RSA_PADDING;
2888 logevent("We believe remote version has SSH-2 RSA padding bug");
2891 if (conf_get_int(ssh->conf, CONF_sshbug_pksessid2) == FORCE_ON ||
2892 (conf_get_int(ssh->conf, CONF_sshbug_pksessid2) == AUTO &&
2893 wc_match("OpenSSH_2.[0-2]*", imp))) {
2895 * These versions have the SSH-2 session-ID bug in
2896 * public-key authentication.
2898 ssh->remote_bugs |= BUG_SSH2_PK_SESSIONID;
2899 logevent("We believe remote version has SSH-2 public-key-session-ID bug");
2902 if (conf_get_int(ssh->conf, CONF_sshbug_rekey2) == FORCE_ON ||
2903 (conf_get_int(ssh->conf, CONF_sshbug_rekey2) == AUTO &&
2904 (wc_match("DigiSSH_2.0", imp) ||
2905 wc_match("OpenSSH_2.[0-4]*", imp) ||
2906 wc_match("OpenSSH_2.5.[0-3]*", imp) ||
2907 wc_match("Sun_SSH_1.0", imp) ||
2908 wc_match("Sun_SSH_1.0.1", imp) ||
2909 /* All versions <= 1.2.6 (they changed their format in 1.2.7) */
2910 wc_match("WeOnlyDo-*", imp)))) {
2912 * These versions have the SSH-2 rekey bug.
2914 ssh->remote_bugs |= BUG_SSH2_REKEY;
2915 logevent("We believe remote version has SSH-2 rekey bug");
2918 if (conf_get_int(ssh->conf, CONF_sshbug_maxpkt2) == FORCE_ON ||
2919 (conf_get_int(ssh->conf, CONF_sshbug_maxpkt2) == AUTO &&
2920 (wc_match("1.36_sshlib GlobalSCAPE", imp) ||
2921 wc_match("1.36 sshlib: GlobalScape", imp)))) {
2923 * This version ignores our makpkt and needs to be throttled.
2925 ssh->remote_bugs |= BUG_SSH2_MAXPKT;
2926 logevent("We believe remote version ignores SSH-2 maximum packet size");
2929 if (conf_get_int(ssh->conf, CONF_sshbug_ignore2) == FORCE_ON) {
2931 * Servers that don't support SSH2_MSG_IGNORE. Currently,
2932 * none detected automatically.
2934 ssh->remote_bugs |= BUG_CHOKES_ON_SSH2_IGNORE;
2935 logevent("We believe remote version has SSH-2 ignore bug");
2938 if (conf_get_int(ssh->conf, CONF_sshbug_oldgex2) == FORCE_ON ||
2939 (conf_get_int(ssh->conf, CONF_sshbug_oldgex2) == AUTO &&
2940 (wc_match("OpenSSH_2.[235]*", imp)))) {
2942 * These versions only support the original (pre-RFC4419)
2943 * SSH-2 GEX request, and disconnect with a protocol error if
2944 * we use the newer version.
2946 ssh->remote_bugs |= BUG_SSH2_OLDGEX;
2947 logevent("We believe remote version has outdated SSH-2 GEX");
2950 if (conf_get_int(ssh->conf, CONF_sshbug_winadj) == FORCE_ON) {
2952 * Servers that don't support our winadj request for one
2953 * reason or another. Currently, none detected automatically.
2955 ssh->remote_bugs |= BUG_CHOKES_ON_WINADJ;
2956 logevent("We believe remote version has winadj bug");
2959 if (conf_get_int(ssh->conf, CONF_sshbug_chanreq) == FORCE_ON ||
2960 (conf_get_int(ssh->conf, CONF_sshbug_chanreq) == AUTO &&
2961 (wc_match("OpenSSH_[2-5].*", imp) ||
2962 wc_match("OpenSSH_6.[0-6]*", imp) ||
2963 wc_match("dropbear_0.[2-4][0-9]*", imp) ||
2964 wc_match("dropbear_0.5[01]*", imp)))) {
2966 * These versions have the SSH-2 channel request bug.
2967 * OpenSSH 6.7 and above do not:
2968 * https://bugzilla.mindrot.org/show_bug.cgi?id=1818
2969 * dropbear_0.52 and above do not:
2970 * https://secure.ucc.asn.au/hg/dropbear/rev/cd02449b709c
2972 ssh->remote_bugs |= BUG_SENDS_LATE_REQUEST_REPLY;
2973 logevent("We believe remote version has SSH-2 channel request bug");
2978 * The `software version' part of an SSH version string is required
2979 * to contain no spaces or minus signs.
2981 static void ssh_fix_verstring(char *str)
2983 /* Eat "<protoversion>-". */
2984 while (*str && *str != '-') str++;
2985 assert(*str == '-'); str++;
2987 /* Convert minus signs and spaces in the remaining string into
2990 if (*str == '-' || *str == ' ')
2997 * Send an appropriate SSH version string.
2999 static void ssh_send_verstring(Ssh ssh, const char *protoname, char *svers)
3003 if (ssh->version == 2) {
3005 * Construct a v2 version string.
3007 verstring = dupprintf("%s2.0-%s\015\012", protoname, sshver);
3010 * Construct a v1 version string.
3012 assert(!strcmp(protoname, "SSH-")); /* no v1 bare connection protocol */
3013 verstring = dupprintf("SSH-%s-%s\012",
3014 (ssh_versioncmp(svers, "1.5") <= 0 ?
3019 ssh_fix_verstring(verstring + strlen(protoname));
3021 /* FUZZING make PuTTY insecure, so make live use difficult. */
3025 if (ssh->version == 2) {
3028 * Record our version string.
3030 len = strcspn(verstring, "\015\012");
3031 ssh->v_c = snewn(len + 1, char);
3032 memcpy(ssh->v_c, verstring, len);
3036 logeventf(ssh, "We claim version: %.*s",
3037 strcspn(verstring, "\015\012"), verstring);
3038 s_write(ssh, verstring, strlen(verstring));
3042 static int do_ssh_init(Ssh ssh, unsigned char c)
3044 static const char protoname[] = "SSH-";
3046 struct do_ssh_init_state {
3055 crState(do_ssh_init_state);
3059 /* Search for a line beginning with the protocol name prefix in
3062 for (s->i = 0; protoname[s->i]; s->i++) {
3063 if ((char)c != protoname[s->i]) goto no;
3073 s->vstrsize = sizeof(protoname) + 16;
3074 s->vstring = snewn(s->vstrsize, char);
3075 strcpy(s->vstring, protoname);
3076 s->vslen = strlen(protoname);
3079 if (s->vslen >= s->vstrsize - 1) {
3081 s->vstring = sresize(s->vstring, s->vstrsize, char);
3083 s->vstring[s->vslen++] = c;
3086 s->version[s->i] = '\0';
3088 } else if (s->i < sizeof(s->version) - 1)
3089 s->version[s->i++] = c;
3090 } else if (c == '\012')
3092 crReturn(1); /* get another char */
3095 ssh->agentfwd_enabled = FALSE;
3096 ssh->rdpkt2_state.incoming_sequence = 0;
3098 s->vstring[s->vslen] = 0;
3099 s->vstring[strcspn(s->vstring, "\015\012")] = '\0';/* remove EOL chars */
3100 logeventf(ssh, "Server version: %s", s->vstring);
3101 ssh_detect_bugs(ssh, s->vstring);
3104 * Decide which SSH protocol version to support.
3107 /* Anything strictly below "2.0" means protocol 1 is supported. */
3108 s->proto1 = ssh_versioncmp(s->version, "2.0") < 0;
3109 /* Anything greater or equal to "1.99" means protocol 2 is supported. */
3110 s->proto2 = ssh_versioncmp(s->version, "1.99") >= 0;
3112 if (conf_get_int(ssh->conf, CONF_sshprot) == 0 && !s->proto1) {
3113 bombout(("SSH protocol version 1 required by configuration but "
3114 "not provided by server"));
3117 if (conf_get_int(ssh->conf, CONF_sshprot) == 3 && !s->proto2) {
3118 bombout(("SSH protocol version 2 required by configuration but "
3119 "not provided by server"));
3123 if (s->proto2 && (conf_get_int(ssh->conf, CONF_sshprot) >= 2 || !s->proto1))
3128 logeventf(ssh, "Using SSH protocol version %d", ssh->version);
3130 /* Send the version string, if we haven't already */
3131 if (conf_get_int(ssh->conf, CONF_sshprot) != 3)
3132 ssh_send_verstring(ssh, protoname, s->version);
3134 if (ssh->version == 2) {
3137 * Record their version string.
3139 len = strcspn(s->vstring, "\015\012");
3140 ssh->v_s = snewn(len + 1, char);
3141 memcpy(ssh->v_s, s->vstring, len);
3145 * Initialise SSH-2 protocol.
3147 ssh->protocol = ssh2_protocol;
3148 ssh2_protocol_setup(ssh);
3149 ssh->s_rdpkt = ssh2_rdpkt;
3152 * Initialise SSH-1 protocol.
3154 ssh->protocol = ssh1_protocol;
3155 ssh1_protocol_setup(ssh);
3156 ssh->s_rdpkt = ssh1_rdpkt;
3158 if (ssh->version == 2)
3159 do_ssh2_transport(ssh, NULL, -1, NULL);
3161 update_specials_menu(ssh->frontend);
3162 ssh->state = SSH_STATE_BEFORE_SIZE;
3163 ssh->pinger = pinger_new(ssh->conf, &ssh_backend, ssh);
3170 static int do_ssh_connection_init(Ssh ssh, unsigned char c)
3173 * Ordinary SSH begins with the banner "SSH-x.y-...". This is just
3174 * the ssh-connection part, extracted and given a trivial binary
3175 * packet protocol, so we replace 'SSH-' at the start with a new
3176 * name. In proper SSH style (though of course this part of the
3177 * proper SSH protocol _isn't_ subject to this kind of
3178 * DNS-domain-based extension), we define the new name in our
3181 static const char protoname[] =
3182 "SSHCONNECTION@putty.projects.tartarus.org-";
3184 struct do_ssh_connection_init_state {
3192 crState(do_ssh_connection_init_state);
3196 /* Search for a line beginning with the protocol name prefix in
3199 for (s->i = 0; protoname[s->i]; s->i++) {
3200 if ((char)c != protoname[s->i]) goto no;
3210 s->vstrsize = sizeof(protoname) + 16;
3211 s->vstring = snewn(s->vstrsize, char);
3212 strcpy(s->vstring, protoname);
3213 s->vslen = strlen(protoname);
3216 if (s->vslen >= s->vstrsize - 1) {
3218 s->vstring = sresize(s->vstring, s->vstrsize, char);
3220 s->vstring[s->vslen++] = c;
3223 s->version[s->i] = '\0';
3225 } else if (s->i < sizeof(s->version) - 1)
3226 s->version[s->i++] = c;
3227 } else if (c == '\012')
3229 crReturn(1); /* get another char */
3232 ssh->agentfwd_enabled = FALSE;
3233 ssh->rdpkt2_bare_state.incoming_sequence = 0;
3235 s->vstring[s->vslen] = 0;
3236 s->vstring[strcspn(s->vstring, "\015\012")] = '\0';/* remove EOL chars */
3237 logeventf(ssh, "Server version: %s", s->vstring);
3238 ssh_detect_bugs(ssh, s->vstring);
3241 * Decide which SSH protocol version to support. This is easy in
3242 * bare ssh-connection mode: only 2.0 is legal.
3244 if (ssh_versioncmp(s->version, "2.0") < 0) {
3245 bombout(("Server announces compatibility with SSH-1 in bare ssh-connection protocol"));
3248 if (conf_get_int(ssh->conf, CONF_sshprot) == 0) {
3249 bombout(("Bare ssh-connection protocol cannot be run in SSH-1-only mode"));
3255 logeventf(ssh, "Using bare ssh-connection protocol");
3257 /* Send the version string, if we haven't already */
3258 ssh_send_verstring(ssh, protoname, s->version);
3261 * Initialise bare connection protocol.
3263 ssh->protocol = ssh2_bare_connection_protocol;
3264 ssh2_bare_connection_protocol_setup(ssh);
3265 ssh->s_rdpkt = ssh2_bare_connection_rdpkt;
3267 update_specials_menu(ssh->frontend);
3268 ssh->state = SSH_STATE_BEFORE_SIZE;
3269 ssh->pinger = pinger_new(ssh->conf, &ssh_backend, ssh);
3272 * Get authconn (really just conn) under way.
3274 do_ssh2_authconn(ssh, NULL, 0, NULL);
3281 static void ssh_process_incoming_data(Ssh ssh,
3282 const unsigned char **data, int *datalen)
3284 struct Packet *pktin;
3286 pktin = ssh->s_rdpkt(ssh, data, datalen);
3288 ssh->protocol(ssh, NULL, 0, pktin);
3289 ssh_free_packet(pktin);
3293 static void ssh_queue_incoming_data(Ssh ssh,
3294 const unsigned char **data, int *datalen)
3296 bufchain_add(&ssh->queued_incoming_data, *data, *datalen);
3301 static void ssh_process_queued_incoming_data(Ssh ssh)
3304 const unsigned char *data;
3307 while (!ssh->frozen && bufchain_size(&ssh->queued_incoming_data)) {
3308 bufchain_prefix(&ssh->queued_incoming_data, &vdata, &len);
3312 while (!ssh->frozen && len > 0)
3313 ssh_process_incoming_data(ssh, &data, &len);
3316 bufchain_consume(&ssh->queued_incoming_data, origlen - len);
3320 static void ssh_set_frozen(Ssh ssh, int frozen)
3323 sk_set_frozen(ssh->s, frozen);
3324 ssh->frozen = frozen;
3327 static void ssh_gotdata(Ssh ssh, const unsigned char *data, int datalen)
3329 /* Log raw data, if we're in that mode. */
3331 log_packet(ssh->logctx, PKT_INCOMING, -1, NULL, data, datalen,
3332 0, NULL, NULL, 0, NULL);
3334 crBegin(ssh->ssh_gotdata_crstate);
3337 * To begin with, feed the characters one by one to the
3338 * protocol initialisation / selection function do_ssh_init().
3339 * When that returns 0, we're done with the initial greeting
3340 * exchange and can move on to packet discipline.
3343 int ret; /* need not be kept across crReturn */
3345 crReturnV; /* more data please */
3346 ret = ssh->do_ssh_init(ssh, *data);
3354 * We emerge from that loop when the initial negotiation is
3355 * over and we have selected an s_rdpkt function. Now pass
3356 * everything to s_rdpkt, and then pass the resulting packets
3357 * to the proper protocol handler.
3361 while (bufchain_size(&ssh->queued_incoming_data) > 0 || datalen > 0) {
3363 ssh_queue_incoming_data(ssh, &data, &datalen);
3364 /* This uses up all data and cannot cause anything interesting
3365 * to happen; indeed, for anything to happen at all, we must
3366 * return, so break out. */
3368 } else if (bufchain_size(&ssh->queued_incoming_data) > 0) {
3369 /* This uses up some or all data, and may freeze the
3371 ssh_process_queued_incoming_data(ssh);
3373 /* This uses up some or all data, and may freeze the
3375 ssh_process_incoming_data(ssh, &data, &datalen);
3377 /* FIXME this is probably EBW. */
3378 if (ssh->state == SSH_STATE_CLOSED)
3381 /* We're out of data. Go and get some more. */
3387 static int ssh_do_close(Ssh ssh, int notify_exit)
3390 struct ssh_channel *c;
3392 ssh->state = SSH_STATE_CLOSED;
3393 expire_timer_context(ssh);
3398 notify_remote_exit(ssh->frontend);
3403 * Now we must shut down any port- and X-forwarded channels going
3404 * through this connection.
3406 if (ssh->channels) {
3407 while (NULL != (c = index234(ssh->channels, 0))) {
3410 x11_close(c->u.x11.xconn);
3413 case CHAN_SOCKDATA_DORMANT:
3414 pfd_close(c->u.pfd.pf);
3417 del234(ssh->channels, c); /* moving next one to index 0 */
3418 if (ssh->version == 2)
3419 bufchain_clear(&c->v.v2.outbuffer);
3424 * Go through port-forwardings, and close any associated
3425 * listening sockets.
3427 if (ssh->portfwds) {
3428 struct ssh_portfwd *pf;
3429 while (NULL != (pf = index234(ssh->portfwds, 0))) {
3430 /* Dispose of any listening socket. */
3432 pfl_terminate(pf->local);
3433 del234(ssh->portfwds, pf); /* moving next one to index 0 */
3436 freetree234(ssh->portfwds);
3437 ssh->portfwds = NULL;
3441 * Also stop attempting to connection-share.
3443 if (ssh->connshare) {
3444 sharestate_free(ssh->connshare);
3445 ssh->connshare = NULL;
3451 static void ssh_socket_log(Plug plug, int type, SockAddr addr, int port,
3452 const char *error_msg, int error_code)
3454 Ssh ssh = (Ssh) plug;
3457 * While we're attempting connection sharing, don't loudly log
3458 * everything that happens. Real TCP connections need to be logged
3459 * when we _start_ trying to connect, because it might be ages
3460 * before they respond if something goes wrong; but connection
3461 * sharing is local and quick to respond, and it's sufficient to
3462 * simply wait and see whether it worked afterwards.
3465 if (!ssh->attempting_connshare)
3466 backend_socket_log(ssh->frontend, type, addr, port,
3467 error_msg, error_code);
3470 void ssh_connshare_log(Ssh ssh, int event, const char *logtext,
3471 const char *ds_err, const char *us_err)
3473 if (event == SHARE_NONE) {
3474 /* In this case, 'logtext' is an error message indicating a
3475 * reason why connection sharing couldn't be set up _at all_.
3476 * Failing that, ds_err and us_err indicate why we couldn't be
3477 * a downstream and an upstream respectively. */
3479 logeventf(ssh, "Could not set up connection sharing: %s", logtext);
3482 logeventf(ssh, "Could not set up connection sharing"
3483 " as downstream: %s", ds_err);
3485 logeventf(ssh, "Could not set up connection sharing"
3486 " as upstream: %s", us_err);
3488 } else if (event == SHARE_DOWNSTREAM) {
3489 /* In this case, 'logtext' is a local endpoint address */
3490 logeventf(ssh, "Using existing shared connection at %s", logtext);
3491 /* Also we should mention this in the console window to avoid
3492 * confusing users as to why this window doesn't behave the
3494 if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
3495 c_write_str(ssh,"Reusing a shared connection to this server.\r\n");
3497 } else if (event == SHARE_UPSTREAM) {
3498 /* In this case, 'logtext' is a local endpoint address too */
3499 logeventf(ssh, "Sharing this connection at %s", logtext);
3503 static int ssh_closing(Plug plug, const char *error_msg, int error_code,
3506 Ssh ssh = (Ssh) plug;
3507 int need_notify = ssh_do_close(ssh, FALSE);
3510 if (!ssh->close_expected)
3511 error_msg = "Server unexpectedly closed network connection";
3513 error_msg = "Server closed network connection";
3516 if (ssh->close_expected && ssh->clean_exit && ssh->exitcode < 0)
3520 notify_remote_exit(ssh->frontend);
3523 logevent(error_msg);
3524 if (!ssh->close_expected || !ssh->clean_exit)
3525 connection_fatal(ssh->frontend, "%s", error_msg);
3529 static int ssh_receive(Plug plug, int urgent, char *data, int len)
3531 Ssh ssh = (Ssh) plug;
3532 ssh_gotdata(ssh, (unsigned char *)data, len);
3533 if (ssh->state == SSH_STATE_CLOSED) {
3534 ssh_do_close(ssh, TRUE);
3540 static void ssh_sent(Plug plug, int bufsize)
3542 Ssh ssh = (Ssh) plug;
3544 * If the send backlog on the SSH socket itself clears, we
3545 * should unthrottle the whole world if it was throttled.
3547 if (bufsize < SSH_MAX_BACKLOG)
3548 ssh_throttle_all(ssh, 0, bufsize);
3551 static void ssh_hostport_setup(const char *host, int port, Conf *conf,
3552 char **savedhost, int *savedport,
3555 char *loghost = conf_get_str(conf, CONF_loghost);
3557 *loghost_ret = loghost;
3563 tmphost = dupstr(loghost);
3564 *savedport = 22; /* default ssh port */
3567 * A colon suffix on the hostname string also lets us affect
3568 * savedport. (Unless there are multiple colons, in which case
3569 * we assume this is an unbracketed IPv6 literal.)
3571 colon = host_strrchr(tmphost, ':');
3572 if (colon && colon == host_strchr(tmphost, ':')) {
3575 *savedport = atoi(colon);
3578 *savedhost = host_strduptrim(tmphost);
3581 *savedhost = host_strduptrim(host);
3583 port = 22; /* default ssh port */
3588 static int ssh_test_for_upstream(const char *host, int port, Conf *conf)
3594 random_ref(); /* platform may need this to determine share socket name */
3595 ssh_hostport_setup(host, port, conf, &savedhost, &savedport, NULL);
3596 ret = ssh_share_test_for_upstream(savedhost, savedport, conf);
3604 * Connect to specified host and port.
3605 * Returns an error message, or NULL on success.
3606 * Also places the canonical host name into `realhost'. It must be
3607 * freed by the caller.
3609 static const char *connect_to_host(Ssh ssh, const char *host, int port,
3610 char **realhost, int nodelay, int keepalive)
3612 static const struct plug_function_table fn_table = {
3623 int addressfamily, sshprot;
3625 ssh_hostport_setup(host, port, ssh->conf,
3626 &ssh->savedhost, &ssh->savedport, &loghost);
3628 ssh->fn = &fn_table; /* make 'ssh' usable as a Plug */
3631 * Try connection-sharing, in case that means we don't open a
3632 * socket after all. ssh_connection_sharing_init will connect to a
3633 * previously established upstream if it can, and failing that,
3634 * establish a listening socket for _us_ to be the upstream. In
3635 * the latter case it will return NULL just as if it had done
3636 * nothing, because here we only need to care if we're a
3637 * downstream and need to do our connection setup differently.
3639 ssh->connshare = NULL;
3640 ssh->attempting_connshare = TRUE; /* affects socket logging behaviour */
3641 ssh->s = ssh_connection_sharing_init(ssh->savedhost, ssh->savedport,
3642 ssh->conf, ssh, &ssh->connshare);
3643 ssh->attempting_connshare = FALSE;
3644 if (ssh->s != NULL) {
3646 * We are a downstream.
3648 ssh->bare_connection = TRUE;
3649 ssh->do_ssh_init = do_ssh_connection_init;
3650 ssh->fullhostname = NULL;
3651 *realhost = dupstr(host); /* best we can do */
3654 * We're not a downstream, so open a normal socket.
3656 ssh->do_ssh_init = do_ssh_init;
3661 addressfamily = conf_get_int(ssh->conf, CONF_addressfamily);
3662 addr = name_lookup(host, port, realhost, ssh->conf, addressfamily,
3663 ssh->frontend, "SSH connection");
3664 if ((err = sk_addr_error(addr)) != NULL) {
3668 ssh->fullhostname = dupstr(*realhost); /* save in case of GSSAPI */
3670 ssh->s = new_connection(addr, *realhost, port,
3671 0, 1, nodelay, keepalive,
3672 (Plug) ssh, ssh->conf);
3673 if ((err = sk_socket_error(ssh->s)) != NULL) {
3675 notify_remote_exit(ssh->frontend);
3681 * If the SSH version number's fixed, set it now, and if it's SSH-2,
3682 * send the version string too.
3684 sshprot = conf_get_int(ssh->conf, CONF_sshprot);
3687 if (sshprot == 3 && !ssh->bare_connection) {
3689 ssh_send_verstring(ssh, "SSH-", NULL);
3693 * loghost, if configured, overrides realhost.
3697 *realhost = dupstr(loghost);
3704 * Throttle or unthrottle the SSH connection.
3706 static void ssh_throttle_conn(Ssh ssh, int adjust)
3708 int old_count = ssh->conn_throttle_count;
3709 ssh->conn_throttle_count += adjust;
3710 assert(ssh->conn_throttle_count >= 0);
3711 if (ssh->conn_throttle_count && !old_count) {
3712 ssh_set_frozen(ssh, 1);
3713 } else if (!ssh->conn_throttle_count && old_count) {
3714 ssh_set_frozen(ssh, 0);
3719 * Throttle or unthrottle _all_ local data streams (for when sends
3720 * on the SSH connection itself back up).
3722 static void ssh_throttle_all(Ssh ssh, int enable, int bufsize)
3725 struct ssh_channel *c;
3727 if (enable == ssh->throttled_all)
3729 ssh->throttled_all = enable;
3730 ssh->overall_bufsize = bufsize;
3733 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
3735 case CHAN_MAINSESSION:
3737 * This is treated separately, outside the switch.
3741 x11_override_throttle(c->u.x11.xconn, enable);
3744 /* Agent channels require no buffer management. */
3747 pfd_override_throttle(c->u.pfd.pf, enable);
3753 static void ssh_agent_callback(void *sshv, void *reply, int replylen)
3755 Ssh ssh = (Ssh) sshv;
3757 ssh->agent_response = reply;
3758 ssh->agent_response_len = replylen;
3760 if (ssh->version == 1)
3761 do_ssh1_login(ssh, NULL, -1, NULL);
3763 do_ssh2_authconn(ssh, NULL, -1, NULL);
3766 static void ssh_dialog_callback(void *sshv, int ret)
3768 Ssh ssh = (Ssh) sshv;
3770 ssh->user_response = ret;
3772 if (ssh->version == 1)
3773 do_ssh1_login(ssh, NULL, -1, NULL);
3775 do_ssh2_transport(ssh, NULL, -1, NULL);
3778 * This may have unfrozen the SSH connection, so do a
3781 ssh_process_queued_incoming_data(ssh);
3784 static void ssh_agentf_callback(void *cv, void *reply, int replylen)
3786 struct ssh_channel *c = (struct ssh_channel *)cv;
3788 const void *sentreply = reply;
3790 c->u.a.outstanding_requests--;
3792 /* Fake SSH_AGENT_FAILURE. */
3793 sentreply = "\0\0\0\1\5";
3796 if (ssh->version == 2) {
3797 ssh2_add_channel_data(c, sentreply, replylen);
3800 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
3801 PKT_INT, c->remoteid,
3803 PKT_DATA, sentreply, replylen,
3809 * If we've already seen an incoming EOF but haven't sent an
3810 * outgoing one, this may be the moment to send it.
3812 if (c->u.a.outstanding_requests == 0 && (c->closes & CLOSES_RCVD_EOF))
3813 sshfwd_write_eof(c);
3817 * Client-initiated disconnection. Send a DISCONNECT if `wire_reason'
3818 * non-NULL, otherwise just close the connection. `client_reason' == NULL
3819 * => log `wire_reason'.
3821 static void ssh_disconnect(Ssh ssh, const char *client_reason,
3822 const char *wire_reason,
3823 int code, int clean_exit)
3827 client_reason = wire_reason;
3829 error = dupprintf("Disconnected: %s", client_reason);
3831 error = dupstr("Disconnected");
3833 if (ssh->version == 1) {
3834 send_packet(ssh, SSH1_MSG_DISCONNECT, PKT_STR, wire_reason,
3836 } else if (ssh->version == 2) {
3837 struct Packet *pktout = ssh2_pkt_init(SSH2_MSG_DISCONNECT);
3838 ssh2_pkt_adduint32(pktout, code);
3839 ssh2_pkt_addstring(pktout, wire_reason);
3840 ssh2_pkt_addstring(pktout, "en"); /* language tag */
3841 ssh2_pkt_send_noqueue(ssh, pktout);
3844 ssh->close_expected = TRUE;
3845 ssh->clean_exit = clean_exit;
3846 ssh_closing((Plug)ssh, error, 0, 0);
3850 int verify_ssh_manual_host_key(Ssh ssh, const char *fingerprint,
3851 const struct ssh_signkey *ssh2keytype,
3854 if (!conf_get_str_nthstrkey(ssh->conf, CONF_ssh_manual_hostkeys, 0)) {
3855 return -1; /* no manual keys configured */
3860 * The fingerprint string we've been given will have things
3861 * like 'ssh-rsa 2048' at the front of it. Strip those off and
3862 * narrow down to just the colon-separated hex block at the
3863 * end of the string.
3865 const char *p = strrchr(fingerprint, ' ');
3866 fingerprint = p ? p+1 : fingerprint;
3867 /* Quick sanity checks, including making sure it's in lowercase */
3868 assert(strlen(fingerprint) == 16*3 - 1);
3869 assert(fingerprint[2] == ':');
3870 assert(fingerprint[strspn(fingerprint, "0123456789abcdef:")] == 0);
3872 if (conf_get_str_str_opt(ssh->conf, CONF_ssh_manual_hostkeys,
3874 return 1; /* success */
3879 * Construct the base64-encoded public key blob and see if
3882 unsigned char *binblob;
3884 int binlen, atoms, i;
3885 binblob = ssh2keytype->public_blob(ssh2keydata, &binlen);
3886 atoms = (binlen + 2) / 3;
3887 base64blob = snewn(atoms * 4 + 1, char);
3888 for (i = 0; i < atoms; i++)
3889 base64_encode_atom(binblob + 3*i, binlen - 3*i, base64blob + 4*i);
3890 base64blob[atoms * 4] = '\0';
3892 if (conf_get_str_str_opt(ssh->conf, CONF_ssh_manual_hostkeys,
3895 return 1; /* success */
3904 * Handle the key exchange and user authentication phases.
3906 static int do_ssh1_login(Ssh ssh, const unsigned char *in, int inlen,
3907 struct Packet *pktin)
3910 unsigned char cookie[8], *ptr;
3911 struct MD5Context md5c;
3912 struct do_ssh1_login_state {
3915 unsigned char *rsabuf;
3916 const unsigned char *keystr1, *keystr2;
3917 unsigned long supported_ciphers_mask, supported_auths_mask;
3918 int tried_publickey, tried_agent;
3919 int tis_auth_refused, ccard_auth_refused;
3920 unsigned char session_id[16];
3922 void *publickey_blob;
3923 int publickey_bloblen;
3924 char *publickey_comment;
3925 int privatekey_available, privatekey_encrypted;
3926 prompts_t *cur_prompt;
3929 unsigned char request[5], *response, *p;
3939 struct RSAKey servkey, hostkey;
3941 crState(do_ssh1_login_state);
3948 if (pktin->type != SSH1_SMSG_PUBLIC_KEY) {
3949 bombout(("Public key packet not received"));
3953 logevent("Received public keys");
3955 ptr = ssh_pkt_getdata(pktin, 8);
3957 bombout(("SSH-1 public key packet stopped before random cookie"));
3960 memcpy(cookie, ptr, 8);
3962 if (!ssh1_pkt_getrsakey(pktin, &s->servkey, &s->keystr1) ||
3963 !ssh1_pkt_getrsakey(pktin, &s->hostkey, &s->keystr2)) {
3964 bombout(("Failed to read SSH-1 public keys from public key packet"));
3969 * Log the host key fingerprint.
3973 logevent("Host key fingerprint is:");
3974 strcpy(logmsg, " ");
3975 s->hostkey.comment = NULL;
3976 rsa_fingerprint(logmsg + strlen(logmsg),
3977 sizeof(logmsg) - strlen(logmsg), &s->hostkey);
3981 ssh->v1_remote_protoflags = ssh_pkt_getuint32(pktin);
3982 s->supported_ciphers_mask = ssh_pkt_getuint32(pktin);
3983 s->supported_auths_mask = ssh_pkt_getuint32(pktin);
3984 if ((ssh->remote_bugs & BUG_CHOKES_ON_RSA))
3985 s->supported_auths_mask &= ~(1 << SSH1_AUTH_RSA);
3987 ssh->v1_local_protoflags =
3988 ssh->v1_remote_protoflags & SSH1_PROTOFLAGS_SUPPORTED;
3989 ssh->v1_local_protoflags |= SSH1_PROTOFLAG_SCREEN_NUMBER;
3992 MD5Update(&md5c, s->keystr2, s->hostkey.bytes);
3993 MD5Update(&md5c, s->keystr1, s->servkey.bytes);
3994 MD5Update(&md5c, cookie, 8);
3995 MD5Final(s->session_id, &md5c);
3997 for (i = 0; i < 32; i++)
3998 ssh->session_key[i] = random_byte();
4001 * Verify that the `bits' and `bytes' parameters match.
4003 if (s->hostkey.bits > s->hostkey.bytes * 8 ||
4004 s->servkey.bits > s->servkey.bytes * 8) {
4005 bombout(("SSH-1 public keys were badly formatted"));
4009 s->len = (s->hostkey.bytes > s->servkey.bytes ?
4010 s->hostkey.bytes : s->servkey.bytes);
4012 s->rsabuf = snewn(s->len, unsigned char);
4015 * Verify the host key.
4019 * First format the key into a string.
4021 int len = rsastr_len(&s->hostkey);
4022 char fingerprint[100];
4023 char *keystr = snewn(len, char);
4024 rsastr_fmt(keystr, &s->hostkey);
4025 rsa_fingerprint(fingerprint, sizeof(fingerprint), &s->hostkey);
4027 /* First check against manually configured host keys. */
4028 s->dlgret = verify_ssh_manual_host_key(ssh, fingerprint, NULL, NULL);
4029 if (s->dlgret == 0) { /* did not match */
4030 bombout(("Host key did not appear in manually configured list"));
4033 } else if (s->dlgret < 0) { /* none configured; use standard handling */
4034 ssh_set_frozen(ssh, 1);
4035 s->dlgret = verify_ssh_host_key(ssh->frontend,
4036 ssh->savedhost, ssh->savedport,
4037 "rsa", keystr, fingerprint,
4038 ssh_dialog_callback, ssh);
4043 if (s->dlgret < 0) {
4047 bombout(("Unexpected data from server while waiting"
4048 " for user host key response"));
4051 } while (pktin || inlen > 0);
4052 s->dlgret = ssh->user_response;
4054 ssh_set_frozen(ssh, 0);
4056 if (s->dlgret == 0) {
4057 ssh_disconnect(ssh, "User aborted at host key verification",
4066 for (i = 0; i < 32; i++) {
4067 s->rsabuf[i] = ssh->session_key[i];
4069 s->rsabuf[i] ^= s->session_id[i];
4072 if (s->hostkey.bytes > s->servkey.bytes) {
4073 ret = rsaencrypt(s->rsabuf, 32, &s->servkey);
4075 ret = rsaencrypt(s->rsabuf, s->servkey.bytes, &s->hostkey);
4077 ret = rsaencrypt(s->rsabuf, 32, &s->hostkey);
4079 ret = rsaencrypt(s->rsabuf, s->hostkey.bytes, &s->servkey);
4082 bombout(("SSH-1 public key encryptions failed due to bad formatting"));
4086 logevent("Encrypted session key");
4089 int cipher_chosen = 0, warn = 0;
4090 const char *cipher_string = NULL;
4092 for (i = 0; !cipher_chosen && i < CIPHER_MAX; i++) {
4093 int next_cipher = conf_get_int_int(ssh->conf,
4094 CONF_ssh_cipherlist, i);
4095 if (next_cipher == CIPHER_WARN) {
4096 /* If/when we choose a cipher, warn about it */
4098 } else if (next_cipher == CIPHER_AES) {
4099 /* XXX Probably don't need to mention this. */
4100 logevent("AES not supported in SSH-1, skipping");
4102 switch (next_cipher) {
4103 case CIPHER_3DES: s->cipher_type = SSH_CIPHER_3DES;
4104 cipher_string = "3DES"; break;
4105 case CIPHER_BLOWFISH: s->cipher_type = SSH_CIPHER_BLOWFISH;
4106 cipher_string = "Blowfish"; break;
4107 case CIPHER_DES: s->cipher_type = SSH_CIPHER_DES;
4108 cipher_string = "single-DES"; break;
4110 if (s->supported_ciphers_mask & (1 << s->cipher_type))
4114 if (!cipher_chosen) {
4115 if ((s->supported_ciphers_mask & (1 << SSH_CIPHER_3DES)) == 0)
4116 bombout(("Server violates SSH-1 protocol by not "
4117 "supporting 3DES encryption"));
4119 /* shouldn't happen */
4120 bombout(("No supported ciphers found"));
4124 /* Warn about chosen cipher if necessary. */
4126 ssh_set_frozen(ssh, 1);
4127 s->dlgret = askalg(ssh->frontend, "cipher", cipher_string,
4128 ssh_dialog_callback, ssh);
4129 if (s->dlgret < 0) {
4133 bombout(("Unexpected data from server while waiting"
4134 " for user response"));
4137 } while (pktin || inlen > 0);
4138 s->dlgret = ssh->user_response;
4140 ssh_set_frozen(ssh, 0);
4141 if (s->dlgret == 0) {
4142 ssh_disconnect(ssh, "User aborted at cipher warning", NULL,
4149 switch (s->cipher_type) {
4150 case SSH_CIPHER_3DES:
4151 logevent("Using 3DES encryption");
4153 case SSH_CIPHER_DES:
4154 logevent("Using single-DES encryption");
4156 case SSH_CIPHER_BLOWFISH:
4157 logevent("Using Blowfish encryption");
4161 send_packet(ssh, SSH1_CMSG_SESSION_KEY,
4162 PKT_CHAR, s->cipher_type,
4163 PKT_DATA, cookie, 8,
4164 PKT_CHAR, (s->len * 8) >> 8, PKT_CHAR, (s->len * 8) & 0xFF,
4165 PKT_DATA, s->rsabuf, s->len,
4166 PKT_INT, ssh->v1_local_protoflags, PKT_END);
4168 logevent("Trying to enable encryption...");
4172 ssh->cipher = (s->cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 :
4173 s->cipher_type == SSH_CIPHER_DES ? &ssh_des :
4175 ssh->v1_cipher_ctx = ssh->cipher->make_context();
4176 ssh->cipher->sesskey(ssh->v1_cipher_ctx, ssh->session_key);
4177 logeventf(ssh, "Initialised %s encryption", ssh->cipher->text_name);
4179 ssh->crcda_ctx = crcda_make_context();
4180 logevent("Installing CRC compensation attack detector");
4182 if (s->servkey.modulus) {
4183 sfree(s->servkey.modulus);
4184 s->servkey.modulus = NULL;
4186 if (s->servkey.exponent) {
4187 sfree(s->servkey.exponent);
4188 s->servkey.exponent = NULL;
4190 if (s->hostkey.modulus) {
4191 sfree(s->hostkey.modulus);
4192 s->hostkey.modulus = NULL;
4194 if (s->hostkey.exponent) {
4195 sfree(s->hostkey.exponent);
4196 s->hostkey.exponent = NULL;
4200 if (pktin->type != SSH1_SMSG_SUCCESS) {
4201 bombout(("Encryption not successfully enabled"));
4205 logevent("Successfully started encryption");
4207 fflush(stdout); /* FIXME eh? */
4209 if ((ssh->username = get_remote_username(ssh->conf)) == NULL) {
4210 int ret; /* need not be kept over crReturn */
4211 s->cur_prompt = new_prompts(ssh->frontend);
4212 s->cur_prompt->to_server = TRUE;
4213 s->cur_prompt->name = dupstr("SSH login name");
4214 add_prompt(s->cur_prompt, dupstr("login as: "), TRUE);
4215 ret = get_userpass_input(s->cur_prompt, NULL, 0);
4218 crWaitUntil(!pktin);
4219 ret = get_userpass_input(s->cur_prompt, in, inlen);
4224 * Failed to get a username. Terminate.
4226 free_prompts(s->cur_prompt);
4227 ssh_disconnect(ssh, "No username provided", NULL, 0, TRUE);
4230 ssh->username = dupstr(s->cur_prompt->prompts[0]->result);
4231 free_prompts(s->cur_prompt);
4234 send_packet(ssh, SSH1_CMSG_USER, PKT_STR, ssh->username, PKT_END);
4236 char *userlog = dupprintf("Sent username \"%s\"", ssh->username);
4238 if (flags & FLAG_INTERACTIVE &&
4239 (!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) {
4240 c_write_str(ssh, userlog);
4241 c_write_str(ssh, "\r\n");
4249 if ((s->supported_auths_mask & (1 << SSH1_AUTH_RSA)) == 0) {
4250 /* We must not attempt PK auth. Pretend we've already tried it. */
4251 s->tried_publickey = s->tried_agent = 1;
4253 s->tried_publickey = s->tried_agent = 0;
4255 s->tis_auth_refused = s->ccard_auth_refused = 0;
4257 * Load the public half of any configured keyfile for later use.
4259 s->keyfile = conf_get_filename(ssh->conf, CONF_keyfile);
4260 if (!filename_is_null(s->keyfile)) {
4262 logeventf(ssh, "Reading key file \"%.150s\"",
4263 filename_to_str(s->keyfile));
4264 keytype = key_type(s->keyfile);
4265 if (keytype == SSH_KEYTYPE_SSH1 ||
4266 keytype == SSH_KEYTYPE_SSH1_PUBLIC) {
4268 if (rsakey_pubblob(s->keyfile,
4269 &s->publickey_blob, &s->publickey_bloblen,
4270 &s->publickey_comment, &error)) {
4271 s->privatekey_available = (keytype == SSH_KEYTYPE_SSH1);
4272 if (!s->privatekey_available)
4273 logeventf(ssh, "Key file contains public key only");
4274 s->privatekey_encrypted = rsakey_encrypted(s->keyfile,
4278 logeventf(ssh, "Unable to load key (%s)", error);
4279 msgbuf = dupprintf("Unable to load key file "
4280 "\"%.150s\" (%s)\r\n",
4281 filename_to_str(s->keyfile),
4283 c_write_str(ssh, msgbuf);
4285 s->publickey_blob = NULL;
4289 logeventf(ssh, "Unable to use this key file (%s)",
4290 key_type_to_str(keytype));
4291 msgbuf = dupprintf("Unable to use key file \"%.150s\""
4293 filename_to_str(s->keyfile),
4294 key_type_to_str(keytype));
4295 c_write_str(ssh, msgbuf);
4297 s->publickey_blob = NULL;
4300 s->publickey_blob = NULL;
4302 while (pktin->type == SSH1_SMSG_FAILURE) {
4303 s->pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
4305 if (conf_get_int(ssh->conf, CONF_tryagent) && agent_exists() && !s->tried_agent) {
4307 * Attempt RSA authentication using Pageant.
4313 logevent("Pageant is running. Requesting keys.");
4315 /* Request the keys held by the agent. */
4316 PUT_32BIT(s->request, 1);
4317 s->request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES;
4318 if (!agent_query(s->request, 5, &r, &s->responselen,
4319 ssh_agent_callback, ssh)) {
4323 bombout(("Unexpected data from server while waiting"
4324 " for agent response"));
4327 } while (pktin || inlen > 0);
4328 r = ssh->agent_response;
4329 s->responselen = ssh->agent_response_len;
4331 s->response = (unsigned char *) r;
4332 if (s->response && s->responselen >= 5 &&
4333 s->response[4] == SSH1_AGENT_RSA_IDENTITIES_ANSWER) {
4334 s->p = s->response + 5;
4335 s->nkeys = toint(GET_32BIT(s->p));
4337 logeventf(ssh, "Pageant reported negative key count %d",
4342 logeventf(ssh, "Pageant has %d SSH-1 keys", s->nkeys);
4343 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
4344 unsigned char *pkblob = s->p;
4348 do { /* do while (0) to make breaking easy */
4349 n = ssh1_read_bignum
4350 (s->p, toint(s->responselen-(s->p-s->response)),
4355 n = ssh1_read_bignum
4356 (s->p, toint(s->responselen-(s->p-s->response)),
4361 if (s->responselen - (s->p-s->response) < 4)
4363 s->commentlen = toint(GET_32BIT(s->p));
4365 if (s->commentlen < 0 ||
4366 toint(s->responselen - (s->p-s->response)) <
4369 s->commentp = (char *)s->p;
4370 s->p += s->commentlen;
4374 logevent("Pageant key list packet was truncated");
4378 if (s->publickey_blob) {
4379 if (!memcmp(pkblob, s->publickey_blob,
4380 s->publickey_bloblen)) {
4381 logeventf(ssh, "Pageant key #%d matches "
4382 "configured key file", s->keyi);
4383 s->tried_publickey = 1;
4385 /* Skip non-configured key */
4388 logeventf(ssh, "Trying Pageant key #%d", s->keyi);
4389 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
4390 PKT_BIGNUM, s->key.modulus, PKT_END);
4392 if (pktin->type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
4393 logevent("Key refused");
4396 logevent("Received RSA challenge");
4397 if ((s->challenge = ssh1_pkt_getmp(pktin)) == NULL) {
4398 bombout(("Server's RSA challenge was badly formatted"));
4403 char *agentreq, *q, *ret;
4406 len = 1 + 4; /* message type, bit count */
4407 len += ssh1_bignum_length(s->key.exponent);
4408 len += ssh1_bignum_length(s->key.modulus);
4409 len += ssh1_bignum_length(s->challenge);
4410 len += 16; /* session id */
4411 len += 4; /* response format */
4412 agentreq = snewn(4 + len, char);
4413 PUT_32BIT(agentreq, len);
4415 *q++ = SSH1_AGENTC_RSA_CHALLENGE;
4416 PUT_32BIT(q, bignum_bitcount(s->key.modulus));
4418 q += ssh1_write_bignum(q, s->key.exponent);
4419 q += ssh1_write_bignum(q, s->key.modulus);
4420 q += ssh1_write_bignum(q, s->challenge);
4421 memcpy(q, s->session_id, 16);
4423 PUT_32BIT(q, 1); /* response format */
4424 if (!agent_query(agentreq, len + 4, &vret, &retlen,
4425 ssh_agent_callback, ssh)) {
4430 bombout(("Unexpected data from server"
4431 " while waiting for agent"
4435 } while (pktin || inlen > 0);
4436 vret = ssh->agent_response;
4437 retlen = ssh->agent_response_len;
4442 if (ret[4] == SSH1_AGENT_RSA_RESPONSE) {
4443 logevent("Sending Pageant's response");
4444 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
4445 PKT_DATA, ret + 5, 16,
4449 if (pktin->type == SSH1_SMSG_SUCCESS) {
4451 ("Pageant's response accepted");
4452 if (flags & FLAG_VERBOSE) {
4453 c_write_str(ssh, "Authenticated using"
4455 c_write(ssh, s->commentp,
4457 c_write_str(ssh, "\" from agent\r\n");
4462 ("Pageant's response not accepted");
4465 ("Pageant failed to answer challenge");
4469 logevent("No reply received from Pageant");
4472 freebn(s->key.exponent);
4473 freebn(s->key.modulus);
4474 freebn(s->challenge);
4479 if (s->publickey_blob && !s->tried_publickey)
4480 logevent("Configured key file not in Pageant");
4482 logevent("Failed to get reply from Pageant");
4487 if (s->publickey_blob && s->privatekey_available &&
4488 !s->tried_publickey) {
4490 * Try public key authentication with the specified
4493 int got_passphrase; /* need not be kept over crReturn */
4494 if (flags & FLAG_VERBOSE)
4495 c_write_str(ssh, "Trying public key authentication.\r\n");
4496 s->keyfile = conf_get_filename(ssh->conf, CONF_keyfile);
4497 logeventf(ssh, "Trying public key \"%s\"",
4498 filename_to_str(s->keyfile));
4499 s->tried_publickey = 1;
4500 got_passphrase = FALSE;
4501 while (!got_passphrase) {
4503 * Get a passphrase, if necessary.
4505 char *passphrase = NULL; /* only written after crReturn */
4507 if (!s->privatekey_encrypted) {
4508 if (flags & FLAG_VERBOSE)
4509 c_write_str(ssh, "No passphrase required.\r\n");
4512 int ret; /* need not be kept over crReturn */
4513 s->cur_prompt = new_prompts(ssh->frontend);
4514 s->cur_prompt->to_server = FALSE;
4515 s->cur_prompt->name = dupstr("SSH key passphrase");
4516 add_prompt(s->cur_prompt,
4517 dupprintf("Passphrase for key \"%.100s\": ",
4518 s->publickey_comment), FALSE);
4519 ret = get_userpass_input(s->cur_prompt, NULL, 0);
4522 crWaitUntil(!pktin);
4523 ret = get_userpass_input(s->cur_prompt, in, inlen);
4527 /* Failed to get a passphrase. Terminate. */
4528 free_prompts(s->cur_prompt);
4529 ssh_disconnect(ssh, NULL, "Unable to authenticate",
4533 passphrase = dupstr(s->cur_prompt->prompts[0]->result);
4534 free_prompts(s->cur_prompt);
4537 * Try decrypting key with passphrase.
4539 s->keyfile = conf_get_filename(ssh->conf, CONF_keyfile);
4540 ret = loadrsakey(s->keyfile, &s->key, passphrase,
4543 smemclr(passphrase, strlen(passphrase));
4547 /* Correct passphrase. */
4548 got_passphrase = TRUE;
4549 } else if (ret == 0) {
4550 c_write_str(ssh, "Couldn't load private key from ");
4551 c_write_str(ssh, filename_to_str(s->keyfile));
4552 c_write_str(ssh, " (");
4553 c_write_str(ssh, error);
4554 c_write_str(ssh, ").\r\n");
4555 got_passphrase = FALSE;
4556 break; /* go and try something else */
4557 } else if (ret == -1) {
4558 c_write_str(ssh, "Wrong passphrase.\r\n"); /* FIXME */
4559 got_passphrase = FALSE;
4562 assert(0 && "unexpected return from loadrsakey()");
4563 got_passphrase = FALSE; /* placate optimisers */
4567 if (got_passphrase) {
4570 * Send a public key attempt.
4572 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
4573 PKT_BIGNUM, s->key.modulus, PKT_END);
4576 if (pktin->type == SSH1_SMSG_FAILURE) {
4577 c_write_str(ssh, "Server refused our public key.\r\n");
4578 continue; /* go and try something else */
4580 if (pktin->type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
4581 bombout(("Bizarre response to offer of public key"));
4587 unsigned char buffer[32];
4588 Bignum challenge, response;
4590 if ((challenge = ssh1_pkt_getmp(pktin)) == NULL) {
4591 bombout(("Server's RSA challenge was badly formatted"));
4594 response = rsadecrypt(challenge, &s->key);
4595 freebn(s->key.private_exponent);/* burn the evidence */
4597 for (i = 0; i < 32; i++) {
4598 buffer[i] = bignum_byte(response, 31 - i);
4602 MD5Update(&md5c, buffer, 32);
4603 MD5Update(&md5c, s->session_id, 16);
4604 MD5Final(buffer, &md5c);
4606 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
4607 PKT_DATA, buffer, 16, PKT_END);
4614 if (pktin->type == SSH1_SMSG_FAILURE) {
4615 if (flags & FLAG_VERBOSE)
4616 c_write_str(ssh, "Failed to authenticate with"
4617 " our public key.\r\n");
4618 continue; /* go and try something else */
4619 } else if (pktin->type != SSH1_SMSG_SUCCESS) {
4620 bombout(("Bizarre response to RSA authentication response"));
4624 break; /* we're through! */
4630 * Otherwise, try various forms of password-like authentication.
4632 s->cur_prompt = new_prompts(ssh->frontend);
4634 if (conf_get_int(ssh->conf, CONF_try_tis_auth) &&
4635 (s->supported_auths_mask & (1 << SSH1_AUTH_TIS)) &&
4636 !s->tis_auth_refused) {
4637 s->pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
4638 logevent("Requested TIS authentication");
4639 send_packet(ssh, SSH1_CMSG_AUTH_TIS, PKT_END);
4641 if (pktin->type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
4642 logevent("TIS authentication declined");
4643 if (flags & FLAG_INTERACTIVE)
4644 c_write_str(ssh, "TIS authentication refused.\r\n");
4645 s->tis_auth_refused = 1;
4650 char *instr_suf, *prompt;
4652 ssh_pkt_getstring(pktin, &challenge, &challengelen);
4654 bombout(("TIS challenge packet was badly formed"));
4657 logevent("Received TIS challenge");
4658 s->cur_prompt->to_server = TRUE;
4659 s->cur_prompt->name = dupstr("SSH TIS authentication");
4660 /* Prompt heuristic comes from OpenSSH */
4661 if (memchr(challenge, '\n', challengelen)) {
4662 instr_suf = dupstr("");
4663 prompt = dupprintf("%.*s", challengelen, challenge);
4665 instr_suf = dupprintf("%.*s", challengelen, challenge);
4666 prompt = dupstr("Response: ");
4668 s->cur_prompt->instruction =
4669 dupprintf("Using TIS authentication.%s%s",
4670 (*instr_suf) ? "\n" : "",
4672 s->cur_prompt->instr_reqd = TRUE;
4673 add_prompt(s->cur_prompt, prompt, FALSE);
4677 if (conf_get_int(ssh->conf, CONF_try_tis_auth) &&
4678 (s->supported_auths_mask & (1 << SSH1_AUTH_CCARD)) &&
4679 !s->ccard_auth_refused) {
4680 s->pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE;
4681 logevent("Requested CryptoCard authentication");
4682 send_packet(ssh, SSH1_CMSG_AUTH_CCARD, PKT_END);
4684 if (pktin->type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
4685 logevent("CryptoCard authentication declined");
4686 c_write_str(ssh, "CryptoCard authentication refused.\r\n");
4687 s->ccard_auth_refused = 1;
4692 char *instr_suf, *prompt;
4694 ssh_pkt_getstring(pktin, &challenge, &challengelen);
4696 bombout(("CryptoCard challenge packet was badly formed"));
4699 logevent("Received CryptoCard challenge");
4700 s->cur_prompt->to_server = TRUE;
4701 s->cur_prompt->name = dupstr("SSH CryptoCard authentication");
4702 s->cur_prompt->name_reqd = FALSE;
4703 /* Prompt heuristic comes from OpenSSH */
4704 if (memchr(challenge, '\n', challengelen)) {
4705 instr_suf = dupstr("");
4706 prompt = dupprintf("%.*s", challengelen, challenge);
4708 instr_suf = dupprintf("%.*s", challengelen, challenge);
4709 prompt = dupstr("Response: ");
4711 s->cur_prompt->instruction =
4712 dupprintf("Using CryptoCard authentication.%s%s",
4713 (*instr_suf) ? "\n" : "",
4715 s->cur_prompt->instr_reqd = TRUE;
4716 add_prompt(s->cur_prompt, prompt, FALSE);
4720 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
4721 if ((s->supported_auths_mask & (1 << SSH1_AUTH_PASSWORD)) == 0) {
4722 bombout(("No supported authentication methods available"));
4725 s->cur_prompt->to_server = TRUE;
4726 s->cur_prompt->name = dupstr("SSH password");
4727 add_prompt(s->cur_prompt, dupprintf("%s@%s's password: ",
4728 ssh->username, ssh->savedhost),
4733 * Show password prompt, having first obtained it via a TIS
4734 * or CryptoCard exchange if we're doing TIS or CryptoCard
4738 int ret; /* need not be kept over crReturn */
4739 ret = get_userpass_input(s->cur_prompt, NULL, 0);
4742 crWaitUntil(!pktin);
4743 ret = get_userpass_input(s->cur_prompt, in, inlen);
4748 * Failed to get a password (for example
4749 * because one was supplied on the command line
4750 * which has already failed to work). Terminate.
4752 free_prompts(s->cur_prompt);
4753 ssh_disconnect(ssh, NULL, "Unable to authenticate", 0, TRUE);
4758 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
4760 * Defence against traffic analysis: we send a
4761 * whole bunch of packets containing strings of
4762 * different lengths. One of these strings is the
4763 * password, in a SSH1_CMSG_AUTH_PASSWORD packet.
4764 * The others are all random data in
4765 * SSH1_MSG_IGNORE packets. This way a passive
4766 * listener can't tell which is the password, and
4767 * hence can't deduce the password length.
4769 * Anybody with a password length greater than 16
4770 * bytes is going to have enough entropy in their
4771 * password that a listener won't find it _that_
4772 * much help to know how long it is. So what we'll
4775 * - if password length < 16, we send 15 packets
4776 * containing string lengths 1 through 15
4778 * - otherwise, we let N be the nearest multiple
4779 * of 8 below the password length, and send 8
4780 * packets containing string lengths N through
4781 * N+7. This won't obscure the order of
4782 * magnitude of the password length, but it will
4783 * introduce a bit of extra uncertainty.
4785 * A few servers can't deal with SSH1_MSG_IGNORE, at
4786 * least in this context. For these servers, we need
4787 * an alternative defence. We make use of the fact
4788 * that the password is interpreted as a C string:
4789 * so we can append a NUL, then some random data.
4791 * A few servers can deal with neither SSH1_MSG_IGNORE
4792 * here _nor_ a padded password string.
4793 * For these servers we are left with no defences
4794 * against password length sniffing.
4796 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE) &&
4797 !(ssh->remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) {
4799 * The server can deal with SSH1_MSG_IGNORE, so
4800 * we can use the primary defence.
4802 int bottom, top, pwlen, i;
4805 pwlen = strlen(s->cur_prompt->prompts[0]->result);
4807 bottom = 0; /* zero length passwords are OK! :-) */
4810 bottom = pwlen & ~7;
4814 assert(pwlen >= bottom && pwlen <= top);
4816 randomstr = snewn(top + 1, char);
4818 for (i = bottom; i <= top; i++) {
4820 defer_packet(ssh, s->pwpkt_type,
4821 PKT_STR,s->cur_prompt->prompts[0]->result,
4824 for (j = 0; j < i; j++) {
4826 randomstr[j] = random_byte();
4827 } while (randomstr[j] == '\0');
4829 randomstr[i] = '\0';
4830 defer_packet(ssh, SSH1_MSG_IGNORE,
4831 PKT_STR, randomstr, PKT_END);
4834 logevent("Sending password with camouflage packets");
4835 ssh_pkt_defersend(ssh);
4838 else if (!(ssh->remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) {
4840 * The server can't deal with SSH1_MSG_IGNORE
4841 * but can deal with padded passwords, so we
4842 * can use the secondary defence.
4848 len = strlen(s->cur_prompt->prompts[0]->result);
4849 if (len < sizeof(string)) {
4851 strcpy(string, s->cur_prompt->prompts[0]->result);
4852 len++; /* cover the zero byte */
4853 while (len < sizeof(string)) {
4854 string[len++] = (char) random_byte();
4857 ss = s->cur_prompt->prompts[0]->result;
4859 logevent("Sending length-padded password");
4860 send_packet(ssh, s->pwpkt_type,
4861 PKT_INT, len, PKT_DATA, ss, len,
4865 * The server is believed unable to cope with
4866 * any of our password camouflage methods.
4869 len = strlen(s->cur_prompt->prompts[0]->result);
4870 logevent("Sending unpadded password");
4871 send_packet(ssh, s->pwpkt_type,
4873 PKT_DATA, s->cur_prompt->prompts[0]->result, len,
4877 send_packet(ssh, s->pwpkt_type,
4878 PKT_STR, s->cur_prompt->prompts[0]->result,
4881 logevent("Sent password");
4882 free_prompts(s->cur_prompt);
4884 if (pktin->type == SSH1_SMSG_FAILURE) {
4885 if (flags & FLAG_VERBOSE)
4886 c_write_str(ssh, "Access denied\r\n");
4887 logevent("Authentication refused");
4888 } else if (pktin->type != SSH1_SMSG_SUCCESS) {
4889 bombout(("Strange packet received, type %d", pktin->type));
4895 if (s->publickey_blob) {
4896 sfree(s->publickey_blob);
4897 sfree(s->publickey_comment);
4900 logevent("Authentication successful");
4905 static void ssh_channel_try_eof(struct ssh_channel *c)
4908 assert(c->pending_eof); /* precondition for calling us */
4910 return; /* can't close: not even opened yet */
4911 if (ssh->version == 2 && bufchain_size(&c->v.v2.outbuffer) > 0)
4912 return; /* can't send EOF: pending outgoing data */
4914 c->pending_eof = FALSE; /* we're about to send it */
4915 if (ssh->version == 1) {
4916 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid,
4918 c->closes |= CLOSES_SENT_EOF;
4920 struct Packet *pktout;
4921 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_EOF);
4922 ssh2_pkt_adduint32(pktout, c->remoteid);
4923 ssh2_pkt_send(ssh, pktout);
4924 c->closes |= CLOSES_SENT_EOF;
4925 ssh2_channel_check_close(c);
4929 Conf *sshfwd_get_conf(struct ssh_channel *c)
4935 void sshfwd_write_eof(struct ssh_channel *c)
4939 if (ssh->state == SSH_STATE_CLOSED)
4942 if (c->closes & CLOSES_SENT_EOF)
4945 c->pending_eof = TRUE;
4946 ssh_channel_try_eof(c);
4949 void sshfwd_unclean_close(struct ssh_channel *c, const char *err)
4953 if (ssh->state == SSH_STATE_CLOSED)
4958 x11_close(c->u.x11.xconn);
4959 logeventf(ssh, "Forwarded X11 connection terminated due to local "
4963 case CHAN_SOCKDATA_DORMANT:
4964 pfd_close(c->u.pfd.pf);
4965 logeventf(ssh, "Forwarded port closed due to local error: %s", err);
4968 c->type = CHAN_ZOMBIE;
4969 c->pending_eof = FALSE; /* this will confuse a zombie channel */
4971 ssh2_channel_check_close(c);
4974 int sshfwd_write(struct ssh_channel *c, char *buf, int len)
4978 if (ssh->state == SSH_STATE_CLOSED)
4981 if (ssh->version == 1) {
4982 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
4983 PKT_INT, c->remoteid,
4984 PKT_INT, len, PKT_DATA, buf, len,
4987 * In SSH-1 we can return 0 here - implying that forwarded
4988 * connections are never individually throttled - because
4989 * the only circumstance that can cause throttling will be
4990 * the whole SSH connection backing up, in which case
4991 * _everything_ will be throttled as a whole.
4995 ssh2_add_channel_data(c, buf, len);
4996 return ssh2_try_send(c);
5000 void sshfwd_unthrottle(struct ssh_channel *c, int bufsize)
5005 if (ssh->state == SSH_STATE_CLOSED)
5008 if (ssh->version == 1) {
5009 buflimit = SSH1_BUFFER_LIMIT;
5011 buflimit = c->v.v2.locmaxwin;
5012 ssh2_set_window(c, bufsize < buflimit ? buflimit - bufsize : 0);
5014 if (c->throttling_conn && bufsize <= buflimit) {
5015 c->throttling_conn = 0;
5016 ssh_throttle_conn(ssh, -1);
5020 static void ssh_queueing_handler(Ssh ssh, struct Packet *pktin)
5022 struct queued_handler *qh = ssh->qhead;
5026 assert(pktin->type == qh->msg1 || pktin->type == qh->msg2);
5029 assert(ssh->packet_dispatch[qh->msg1] == ssh_queueing_handler);
5030 ssh->packet_dispatch[qh->msg1] = ssh->q_saved_handler1;
5033 assert(ssh->packet_dispatch[qh->msg2] == ssh_queueing_handler);
5034 ssh->packet_dispatch[qh->msg2] = ssh->q_saved_handler2;
5038 ssh->qhead = qh->next;
5040 if (ssh->qhead->msg1 > 0) {
5041 ssh->q_saved_handler1 = ssh->packet_dispatch[ssh->qhead->msg1];
5042 ssh->packet_dispatch[ssh->qhead->msg1] = ssh_queueing_handler;
5044 if (ssh->qhead->msg2 > 0) {
5045 ssh->q_saved_handler2 = ssh->packet_dispatch[ssh->qhead->msg2];
5046 ssh->packet_dispatch[ssh->qhead->msg2] = ssh_queueing_handler;
5049 ssh->qhead = ssh->qtail = NULL;
5052 qh->handler(ssh, pktin, qh->ctx);
5057 static void ssh_queue_handler(Ssh ssh, int msg1, int msg2,
5058 chandler_fn_t handler, void *ctx)
5060 struct queued_handler *qh;
5062 qh = snew(struct queued_handler);
5065 qh->handler = handler;
5069 if (ssh->qtail == NULL) {
5073 ssh->q_saved_handler1 = ssh->packet_dispatch[ssh->qhead->msg1];
5074 ssh->packet_dispatch[qh->msg1] = ssh_queueing_handler;
5077 ssh->q_saved_handler2 = ssh->packet_dispatch[ssh->qhead->msg2];
5078 ssh->packet_dispatch[qh->msg2] = ssh_queueing_handler;
5081 ssh->qtail->next = qh;
5086 static void ssh_rportfwd_succfail(Ssh ssh, struct Packet *pktin, void *ctx)
5088 struct ssh_rportfwd *rpf, *pf = (struct ssh_rportfwd *)ctx;
5090 if (pktin->type == (ssh->version == 1 ? SSH1_SMSG_SUCCESS :
5091 SSH2_MSG_REQUEST_SUCCESS)) {
5092 logeventf(ssh, "Remote port forwarding from %s enabled",
5095 logeventf(ssh, "Remote port forwarding from %s refused",
5098 rpf = del234(ssh->rportfwds, pf);
5100 pf->pfrec->remote = NULL;
5105 int ssh_alloc_sharing_rportfwd(Ssh ssh, const char *shost, int sport,
5108 struct ssh_rportfwd *pf = snew(struct ssh_rportfwd);
5111 pf->share_ctx = share_ctx;
5112 pf->shost = dupstr(shost);
5114 pf->sportdesc = NULL;
5115 if (!ssh->rportfwds) {
5116 assert(ssh->version == 2);
5117 ssh->rportfwds = newtree234(ssh_rportcmp_ssh2);
5119 if (add234(ssh->rportfwds, pf) != pf) {
5127 static void ssh_sharing_global_request_response(Ssh ssh, struct Packet *pktin,
5130 share_got_pkt_from_server(ctx, pktin->type,
5131 pktin->body, pktin->length);
5134 void ssh_sharing_queue_global_request(Ssh ssh, void *share_ctx)
5136 ssh_queue_handler(ssh, SSH2_MSG_REQUEST_SUCCESS, SSH2_MSG_REQUEST_FAILURE,
5137 ssh_sharing_global_request_response, share_ctx);
5140 static void ssh_setup_portfwd(Ssh ssh, Conf *conf)
5142 struct ssh_portfwd *epf;
5146 if (!ssh->portfwds) {
5147 ssh->portfwds = newtree234(ssh_portcmp);
5150 * Go through the existing port forwardings and tag them
5151 * with status==DESTROY. Any that we want to keep will be
5152 * re-enabled (status==KEEP) as we go through the
5153 * configuration and find out which bits are the same as
5156 struct ssh_portfwd *epf;
5158 for (i = 0; (epf = index234(ssh->portfwds, i)) != NULL; i++)
5159 epf->status = DESTROY;
5162 for (val = conf_get_str_strs(conf, CONF_portfwd, NULL, &key);
5164 val = conf_get_str_strs(conf, CONF_portfwd, key, &key)) {
5165 char *kp, *kp2, *vp, *vp2;
5166 char address_family, type;
5167 int sport,dport,sserv,dserv;
5168 char *sports, *dports, *saddr, *host;
5172 address_family = 'A';
5174 if (*kp == 'A' || *kp == '4' || *kp == '6')
5175 address_family = *kp++;
5176 if (*kp == 'L' || *kp == 'R')
5179 if ((kp2 = host_strchr(kp, ':')) != NULL) {
5181 * There's a colon in the middle of the source port
5182 * string, which means that the part before it is
5183 * actually a source address.
5185 char *saddr_tmp = dupprintf("%.*s", (int)(kp2 - kp), kp);
5186 saddr = host_strduptrim(saddr_tmp);
5193 sport = atoi(sports);
5197 sport = net_service_lookup(sports);
5199 logeventf(ssh, "Service lookup failed for source"
5200 " port \"%s\"", sports);
5204 if (type == 'L' && !strcmp(val, "D")) {
5205 /* dynamic forwarding */
5212 /* ordinary forwarding */
5214 vp2 = vp + host_strcspn(vp, ":");
5215 host = dupprintf("%.*s", (int)(vp2 - vp), vp);
5219 dport = atoi(dports);
5223 dport = net_service_lookup(dports);
5225 logeventf(ssh, "Service lookup failed for destination"
5226 " port \"%s\"", dports);
5231 if (sport && dport) {
5232 /* Set up a description of the source port. */
5233 struct ssh_portfwd *pfrec, *epfrec;
5235 pfrec = snew(struct ssh_portfwd);
5237 pfrec->saddr = saddr;
5238 pfrec->sserv = sserv ? dupstr(sports) : NULL;
5239 pfrec->sport = sport;
5240 pfrec->daddr = host;
5241 pfrec->dserv = dserv ? dupstr(dports) : NULL;
5242 pfrec->dport = dport;
5243 pfrec->local = NULL;
5244 pfrec->remote = NULL;
5245 pfrec->addressfamily = (address_family == '4' ? ADDRTYPE_IPV4 :
5246 address_family == '6' ? ADDRTYPE_IPV6 :
5249 epfrec = add234(ssh->portfwds, pfrec);
5250 if (epfrec != pfrec) {
5251 if (epfrec->status == DESTROY) {
5253 * We already have a port forwarding up and running
5254 * with precisely these parameters. Hence, no need
5255 * to do anything; simply re-tag the existing one
5258 epfrec->status = KEEP;
5261 * Anything else indicates that there was a duplicate
5262 * in our input, which we'll silently ignore.
5264 free_portfwd(pfrec);
5266 pfrec->status = CREATE;
5275 * Now go through and destroy any port forwardings which were
5278 for (i = 0; (epf = index234(ssh->portfwds, i)) != NULL; i++)
5279 if (epf->status == DESTROY) {
5282 message = dupprintf("%s port forwarding from %s%s%d",
5283 epf->type == 'L' ? "local" :
5284 epf->type == 'R' ? "remote" : "dynamic",
5285 epf->saddr ? epf->saddr : "",
5286 epf->saddr ? ":" : "",
5289 if (epf->type != 'D') {
5290 char *msg2 = dupprintf("%s to %s:%d", message,
5291 epf->daddr, epf->dport);
5296 logeventf(ssh, "Cancelling %s", message);
5299 /* epf->remote or epf->local may be NULL if setting up a
5300 * forwarding failed. */
5302 struct ssh_rportfwd *rpf = epf->remote;
5303 struct Packet *pktout;
5306 * Cancel the port forwarding at the server
5309 if (ssh->version == 1) {
5311 * We cannot cancel listening ports on the
5312 * server side in SSH-1! There's no message
5313 * to support it. Instead, we simply remove
5314 * the rportfwd record from the local end
5315 * so that any connections the server tries
5316 * to make on it are rejected.
5319 pktout = ssh2_pkt_init(SSH2_MSG_GLOBAL_REQUEST);
5320 ssh2_pkt_addstring(pktout, "cancel-tcpip-forward");
5321 ssh2_pkt_addbool(pktout, 0);/* _don't_ want reply */
5323 ssh2_pkt_addstring(pktout, epf->saddr);
5324 } else if (conf_get_int(conf, CONF_rport_acceptall)) {
5325 /* XXX: rport_acceptall may not represent
5326 * what was used to open the original connection,
5327 * since it's reconfigurable. */
5328 ssh2_pkt_addstring(pktout, "");
5330 ssh2_pkt_addstring(pktout, "localhost");
5332 ssh2_pkt_adduint32(pktout, epf->sport);
5333 ssh2_pkt_send(ssh, pktout);
5336 del234(ssh->rportfwds, rpf);
5338 } else if (epf->local) {
5339 pfl_terminate(epf->local);
5342 delpos234(ssh->portfwds, i);
5344 i--; /* so we don't skip one in the list */
5348 * And finally, set up any new port forwardings (status==CREATE).
5350 for (i = 0; (epf = index234(ssh->portfwds, i)) != NULL; i++)
5351 if (epf->status == CREATE) {
5352 char *sportdesc, *dportdesc;
5353 sportdesc = dupprintf("%s%s%s%s%d%s",
5354 epf->saddr ? epf->saddr : "",
5355 epf->saddr ? ":" : "",
5356 epf->sserv ? epf->sserv : "",
5357 epf->sserv ? "(" : "",
5359 epf->sserv ? ")" : "");
5360 if (epf->type == 'D') {
5363 dportdesc = dupprintf("%s:%s%s%d%s",
5365 epf->dserv ? epf->dserv : "",
5366 epf->dserv ? "(" : "",
5368 epf->dserv ? ")" : "");
5371 if (epf->type == 'L') {
5372 char *err = pfl_listen(epf->daddr, epf->dport,
5373 epf->saddr, epf->sport,
5374 ssh, conf, &epf->local,
5375 epf->addressfamily);
5377 logeventf(ssh, "Local %sport %s forwarding to %s%s%s",
5378 epf->addressfamily == ADDRTYPE_IPV4 ? "IPv4 " :
5379 epf->addressfamily == ADDRTYPE_IPV6 ? "IPv6 " : "",
5380 sportdesc, dportdesc,
5381 err ? " failed: " : "", err ? err : "");
5384 } else if (epf->type == 'D') {
5385 char *err = pfl_listen(NULL, -1, epf->saddr, epf->sport,
5386 ssh, conf, &epf->local,
5387 epf->addressfamily);
5389 logeventf(ssh, "Local %sport %s SOCKS dynamic forwarding%s%s",
5390 epf->addressfamily == ADDRTYPE_IPV4 ? "IPv4 " :
5391 epf->addressfamily == ADDRTYPE_IPV6 ? "IPv6 " : "",
5393 err ? " failed: " : "", err ? err : "");
5398 struct ssh_rportfwd *pf;
5401 * Ensure the remote port forwardings tree exists.
5403 if (!ssh->rportfwds) {
5404 if (ssh->version == 1)
5405 ssh->rportfwds = newtree234(ssh_rportcmp_ssh1);
5407 ssh->rportfwds = newtree234(ssh_rportcmp_ssh2);
5410 pf = snew(struct ssh_rportfwd);
5411 pf->share_ctx = NULL;
5412 pf->dhost = dupstr(epf->daddr);
5413 pf->dport = epf->dport;
5415 pf->shost = dupstr(epf->saddr);
5416 } else if (conf_get_int(conf, CONF_rport_acceptall)) {
5417 pf->shost = dupstr("");
5419 pf->shost = dupstr("localhost");
5421 pf->sport = epf->sport;
5422 if (add234(ssh->rportfwds, pf) != pf) {
5423 logeventf(ssh, "Duplicate remote port forwarding to %s:%d",
5424 epf->daddr, epf->dport);
5427 logeventf(ssh, "Requesting remote port %s"
5428 " forward to %s", sportdesc, dportdesc);
5430 pf->sportdesc = sportdesc;
5435 if (ssh->version == 1) {
5436 send_packet(ssh, SSH1_CMSG_PORT_FORWARD_REQUEST,
5437 PKT_INT, epf->sport,
5438 PKT_STR, epf->daddr,
5439 PKT_INT, epf->dport,
5441 ssh_queue_handler(ssh, SSH1_SMSG_SUCCESS,
5443 ssh_rportfwd_succfail, pf);
5445 struct Packet *pktout;
5446 pktout = ssh2_pkt_init(SSH2_MSG_GLOBAL_REQUEST);
5447 ssh2_pkt_addstring(pktout, "tcpip-forward");
5448 ssh2_pkt_addbool(pktout, 1);/* want reply */
5449 ssh2_pkt_addstring(pktout, pf->shost);
5450 ssh2_pkt_adduint32(pktout, pf->sport);
5451 ssh2_pkt_send(ssh, pktout);
5453 ssh_queue_handler(ssh, SSH2_MSG_REQUEST_SUCCESS,
5454 SSH2_MSG_REQUEST_FAILURE,
5455 ssh_rportfwd_succfail, pf);
5464 static void ssh1_smsg_stdout_stderr_data(Ssh ssh, struct Packet *pktin)
5467 int stringlen, bufsize;
5469 ssh_pkt_getstring(pktin, &string, &stringlen);
5470 if (string == NULL) {
5471 bombout(("Incoming terminal data packet was badly formed"));
5475 bufsize = from_backend(ssh->frontend, pktin->type == SSH1_SMSG_STDERR_DATA,
5477 if (!ssh->v1_stdout_throttling && bufsize > SSH1_BUFFER_LIMIT) {
5478 ssh->v1_stdout_throttling = 1;
5479 ssh_throttle_conn(ssh, +1);
5483 static void ssh1_smsg_x11_open(Ssh ssh, struct Packet *pktin)
5485 /* Remote side is trying to open a channel to talk to our
5486 * X-Server. Give them back a local channel number. */
5487 struct ssh_channel *c;
5488 int remoteid = ssh_pkt_getuint32(pktin);
5490 logevent("Received X11 connect request");
5491 /* Refuse if X11 forwarding is disabled. */
5492 if (!ssh->X11_fwd_enabled) {
5493 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
5494 PKT_INT, remoteid, PKT_END);
5495 logevent("Rejected X11 connect request");
5497 c = snew(struct ssh_channel);
5500 c->u.x11.xconn = x11_init(ssh->x11authtree, c, NULL, -1);
5501 c->remoteid = remoteid;
5502 c->halfopen = FALSE;
5503 c->localid = alloc_channel_id(ssh);
5505 c->pending_eof = FALSE;
5506 c->throttling_conn = 0;
5507 c->type = CHAN_X11; /* identify channel type */
5508 add234(ssh->channels, c);
5509 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
5510 PKT_INT, c->remoteid, PKT_INT,
5511 c->localid, PKT_END);
5512 logevent("Opened X11 forward channel");
5516 static void ssh1_smsg_agent_open(Ssh ssh, struct Packet *pktin)
5518 /* Remote side is trying to open a channel to talk to our
5519 * agent. Give them back a local channel number. */
5520 struct ssh_channel *c;
5521 int remoteid = ssh_pkt_getuint32(pktin);
5523 /* Refuse if agent forwarding is disabled. */
5524 if (!ssh->agentfwd_enabled) {
5525 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
5526 PKT_INT, remoteid, PKT_END);
5528 c = snew(struct ssh_channel);
5530 c->remoteid = remoteid;
5531 c->halfopen = FALSE;
5532 c->localid = alloc_channel_id(ssh);
5534 c->pending_eof = FALSE;
5535 c->throttling_conn = 0;
5536 c->type = CHAN_AGENT; /* identify channel type */
5537 c->u.a.lensofar = 0;
5538 c->u.a.message = NULL;
5539 c->u.a.outstanding_requests = 0;
5540 add234(ssh->channels, c);
5541 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
5542 PKT_INT, c->remoteid, PKT_INT, c->localid,
5547 static void ssh1_msg_port_open(Ssh ssh, struct Packet *pktin)
5549 /* Remote side is trying to open a channel to talk to a
5550 * forwarded port. Give them back a local channel number. */
5551 struct ssh_rportfwd pf, *pfp;
5557 remoteid = ssh_pkt_getuint32(pktin);
5558 ssh_pkt_getstring(pktin, &host, &hostsize);
5559 port = ssh_pkt_getuint32(pktin);
5561 pf.dhost = dupprintf("%.*s", hostsize, host);
5563 pfp = find234(ssh->rportfwds, &pf, NULL);
5566 logeventf(ssh, "Rejected remote port open request for %s:%d",
5568 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
5569 PKT_INT, remoteid, PKT_END);
5571 struct ssh_channel *c = snew(struct ssh_channel);
5574 logeventf(ssh, "Received remote port open request for %s:%d",
5576 err = pfd_connect(&c->u.pfd.pf, pf.dhost, port,
5577 c, ssh->conf, pfp->pfrec->addressfamily);
5579 logeventf(ssh, "Port open failed: %s", err);
5582 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
5583 PKT_INT, remoteid, PKT_END);
5585 c->remoteid = remoteid;
5586 c->halfopen = FALSE;
5587 c->localid = alloc_channel_id(ssh);
5589 c->pending_eof = FALSE;
5590 c->throttling_conn = 0;
5591 c->type = CHAN_SOCKDATA; /* identify channel type */
5592 add234(ssh->channels, c);
5593 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
5594 PKT_INT, c->remoteid, PKT_INT,
5595 c->localid, PKT_END);
5596 logevent("Forwarded port opened successfully");
5603 static void ssh1_msg_channel_open_confirmation(Ssh ssh, struct Packet *pktin)
5605 unsigned int remoteid = ssh_pkt_getuint32(pktin);
5606 unsigned int localid = ssh_pkt_getuint32(pktin);
5607 struct ssh_channel *c;
5609 c = find234(ssh->channels, &remoteid, ssh_channelfind);
5610 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
5611 c->remoteid = localid;
5612 c->halfopen = FALSE;
5613 c->type = CHAN_SOCKDATA;
5614 c->throttling_conn = 0;
5615 pfd_confirm(c->u.pfd.pf);
5618 if (c && c->pending_eof) {
5620 * We have a pending close on this channel,
5621 * which we decided on before the server acked
5622 * the channel open. So now we know the
5623 * remoteid, we can close it again.
5625 ssh_channel_try_eof(c);
5629 static void ssh1_msg_channel_open_failure(Ssh ssh, struct Packet *pktin)
5631 unsigned int remoteid = ssh_pkt_getuint32(pktin);
5632 struct ssh_channel *c;
5634 c = find234(ssh->channels, &remoteid, ssh_channelfind);
5635 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
5636 logevent("Forwarded connection refused by server");
5637 pfd_close(c->u.pfd.pf);
5638 del234(ssh->channels, c);
5643 static void ssh1_msg_channel_close(Ssh ssh, struct Packet *pktin)
5645 /* Remote side closes a channel. */
5646 unsigned i = ssh_pkt_getuint32(pktin);
5647 struct ssh_channel *c;
5648 c = find234(ssh->channels, &i, ssh_channelfind);
5649 if (c && !c->halfopen) {
5651 if (pktin->type == SSH1_MSG_CHANNEL_CLOSE &&
5652 !(c->closes & CLOSES_RCVD_EOF)) {
5654 * Received CHANNEL_CLOSE, which we translate into
5657 int send_close = FALSE;
5659 c->closes |= CLOSES_RCVD_EOF;
5664 x11_send_eof(c->u.x11.xconn);
5670 pfd_send_eof(c->u.pfd.pf);
5679 if (send_close && !(c->closes & CLOSES_SENT_EOF)) {
5680 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid,
5682 c->closes |= CLOSES_SENT_EOF;
5686 if (pktin->type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION &&
5687 !(c->closes & CLOSES_RCVD_CLOSE)) {
5689 if (!(c->closes & CLOSES_SENT_EOF)) {
5690 bombout(("Received CHANNEL_CLOSE_CONFIRMATION for channel %d"
5691 " for which we never sent CHANNEL_CLOSE\n", i));
5694 c->closes |= CLOSES_RCVD_CLOSE;
5697 if (!((CLOSES_SENT_EOF | CLOSES_RCVD_EOF) & ~c->closes) &&
5698 !(c->closes & CLOSES_SENT_CLOSE)) {
5699 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION,
5700 PKT_INT, c->remoteid, PKT_END);
5701 c->closes |= CLOSES_SENT_CLOSE;
5704 if (!((CLOSES_SENT_CLOSE | CLOSES_RCVD_CLOSE) & ~c->closes))
5705 ssh_channel_destroy(c);
5707 bombout(("Received CHANNEL_CLOSE%s for %s channel %d\n",
5708 pktin->type == SSH1_MSG_CHANNEL_CLOSE ? "" :
5709 "_CONFIRMATION", c ? "half-open" : "nonexistent",
5714 static void ssh1_msg_channel_data(Ssh ssh, struct Packet *pktin)
5716 /* Data sent down one of our channels. */
5717 int i = ssh_pkt_getuint32(pktin);
5720 struct ssh_channel *c;
5722 ssh_pkt_getstring(pktin, &p, &len);
5724 c = find234(ssh->channels, &i, ssh_channelfind);
5729 bufsize = x11_send(c->u.x11.xconn, p, len);
5732 bufsize = pfd_send(c->u.pfd.pf, p, len);
5735 /* Data for an agent message. Buffer it. */
5737 if (c->u.a.lensofar < 4) {
5738 unsigned int l = min(4 - c->u.a.lensofar, (unsigned)len);
5739 memcpy(c->u.a.msglen + c->u.a.lensofar, p,
5743 c->u.a.lensofar += l;
5745 if (c->u.a.lensofar == 4) {
5747 4 + GET_32BIT(c->u.a.msglen);
5748 c->u.a.message = snewn(c->u.a.totallen,
5750 memcpy(c->u.a.message, c->u.a.msglen, 4);
5752 if (c->u.a.lensofar >= 4 && len > 0) {
5754 min(c->u.a.totallen - c->u.a.lensofar,
5756 memcpy(c->u.a.message + c->u.a.lensofar, p,
5760 c->u.a.lensofar += l;
5762 if (c->u.a.lensofar == c->u.a.totallen) {
5765 c->u.a.outstanding_requests++;
5766 if (agent_query(c->u.a.message,
5769 ssh_agentf_callback, c))
5770 ssh_agentf_callback(c, reply, replylen);
5771 sfree(c->u.a.message);
5772 c->u.a.lensofar = 0;
5775 bufsize = 0; /* agent channels never back up */
5778 if (!c->throttling_conn && bufsize > SSH1_BUFFER_LIMIT) {
5779 c->throttling_conn = 1;
5780 ssh_throttle_conn(ssh, +1);
5785 static void ssh1_smsg_exit_status(Ssh ssh, struct Packet *pktin)
5787 ssh->exitcode = ssh_pkt_getuint32(pktin);
5788 logeventf(ssh, "Server sent command exit status %d", ssh->exitcode);
5789 send_packet(ssh, SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
5791 * In case `helpful' firewalls or proxies tack
5792 * extra human-readable text on the end of the
5793 * session which we might mistake for another
5794 * encrypted packet, we close the session once
5795 * we've sent EXIT_CONFIRMATION.
5797 ssh_disconnect(ssh, NULL, NULL, 0, TRUE);
5800 /* Helper function to deal with sending tty modes for REQUEST_PTY */
5801 static void ssh1_send_ttymode(void *data, char *mode, char *val)
5803 struct Packet *pktout = (struct Packet *)data;
5805 unsigned int arg = 0;
5806 while (strcmp(mode, ssh_ttymodes[i].mode) != 0) i++;
5807 if (i == lenof(ssh_ttymodes)) return;
5808 switch (ssh_ttymodes[i].type) {
5810 arg = ssh_tty_parse_specchar(val);
5813 arg = ssh_tty_parse_boolean(val);
5816 ssh2_pkt_addbyte(pktout, ssh_ttymodes[i].opcode);
5817 ssh2_pkt_addbyte(pktout, arg);
5820 int ssh_agent_forwarding_permitted(Ssh ssh)
5822 return conf_get_int(ssh->conf, CONF_agentfwd) && agent_exists();
5825 static void do_ssh1_connection(Ssh ssh, const unsigned char *in, int inlen,
5826 struct Packet *pktin)
5828 crBegin(ssh->do_ssh1_connection_crstate);
5830 ssh->packet_dispatch[SSH1_SMSG_STDOUT_DATA] =
5831 ssh->packet_dispatch[SSH1_SMSG_STDERR_DATA] =
5832 ssh1_smsg_stdout_stderr_data;
5834 ssh->packet_dispatch[SSH1_MSG_CHANNEL_OPEN_CONFIRMATION] =
5835 ssh1_msg_channel_open_confirmation;
5836 ssh->packet_dispatch[SSH1_MSG_CHANNEL_OPEN_FAILURE] =
5837 ssh1_msg_channel_open_failure;
5838 ssh->packet_dispatch[SSH1_MSG_CHANNEL_CLOSE] =
5839 ssh->packet_dispatch[SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION] =
5840 ssh1_msg_channel_close;
5841 ssh->packet_dispatch[SSH1_MSG_CHANNEL_DATA] = ssh1_msg_channel_data;
5842 ssh->packet_dispatch[SSH1_SMSG_EXIT_STATUS] = ssh1_smsg_exit_status;
5844 if (ssh_agent_forwarding_permitted(ssh)) {
5845 logevent("Requesting agent forwarding");
5846 send_packet(ssh, SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END);
5850 if (pktin->type != SSH1_SMSG_SUCCESS
5851 && pktin->type != SSH1_SMSG_FAILURE) {
5852 bombout(("Protocol confusion"));
5854 } else if (pktin->type == SSH1_SMSG_FAILURE) {
5855 logevent("Agent forwarding refused");
5857 logevent("Agent forwarding enabled");
5858 ssh->agentfwd_enabled = TRUE;
5859 ssh->packet_dispatch[SSH1_SMSG_AGENT_OPEN] = ssh1_smsg_agent_open;
5863 if (conf_get_int(ssh->conf, CONF_x11_forward)) {
5865 x11_setup_display(conf_get_str(ssh->conf, CONF_x11_display),
5867 if (!ssh->x11disp) {
5868 /* FIXME: return an error message from x11_setup_display */
5869 logevent("X11 forwarding not enabled: unable to"
5870 " initialise X display");
5872 ssh->x11auth = x11_invent_fake_auth
5873 (ssh->x11authtree, conf_get_int(ssh->conf, CONF_x11_auth));
5874 ssh->x11auth->disp = ssh->x11disp;
5876 logevent("Requesting X11 forwarding");
5877 if (ssh->v1_local_protoflags & SSH1_PROTOFLAG_SCREEN_NUMBER) {
5878 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
5879 PKT_STR, ssh->x11auth->protoname,
5880 PKT_STR, ssh->x11auth->datastring,
5881 PKT_INT, ssh->x11disp->screennum,
5884 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
5885 PKT_STR, ssh->x11auth->protoname,
5886 PKT_STR, ssh->x11auth->datastring,
5892 if (pktin->type != SSH1_SMSG_SUCCESS
5893 && pktin->type != SSH1_SMSG_FAILURE) {
5894 bombout(("Protocol confusion"));
5896 } else if (pktin->type == SSH1_SMSG_FAILURE) {
5897 logevent("X11 forwarding refused");
5899 logevent("X11 forwarding enabled");
5900 ssh->X11_fwd_enabled = TRUE;
5901 ssh->packet_dispatch[SSH1_SMSG_X11_OPEN] = ssh1_smsg_x11_open;
5906 ssh_setup_portfwd(ssh, ssh->conf);
5907 ssh->packet_dispatch[SSH1_MSG_PORT_OPEN] = ssh1_msg_port_open;
5909 if (!conf_get_int(ssh->conf, CONF_nopty)) {
5911 /* Unpick the terminal-speed string. */
5912 /* XXX perhaps we should allow no speeds to be sent. */
5913 ssh->ospeed = 38400; ssh->ispeed = 38400; /* last-resort defaults */
5914 sscanf(conf_get_str(ssh->conf, CONF_termspeed), "%d,%d", &ssh->ospeed, &ssh->ispeed);
5915 /* Send the pty request. */
5916 pkt = ssh1_pkt_init(SSH1_CMSG_REQUEST_PTY);
5917 ssh_pkt_addstring(pkt, conf_get_str(ssh->conf, CONF_termtype));
5918 ssh_pkt_adduint32(pkt, ssh->term_height);
5919 ssh_pkt_adduint32(pkt, ssh->term_width);
5920 ssh_pkt_adduint32(pkt, 0); /* width in pixels */
5921 ssh_pkt_adduint32(pkt, 0); /* height in pixels */
5922 parse_ttymodes(ssh, ssh1_send_ttymode, (void *)pkt);
5923 ssh_pkt_addbyte(pkt, SSH1_TTY_OP_ISPEED);
5924 ssh_pkt_adduint32(pkt, ssh->ispeed);
5925 ssh_pkt_addbyte(pkt, SSH1_TTY_OP_OSPEED);
5926 ssh_pkt_adduint32(pkt, ssh->ospeed);
5927 ssh_pkt_addbyte(pkt, SSH_TTY_OP_END);
5929 ssh->state = SSH_STATE_INTERMED;
5933 if (pktin->type != SSH1_SMSG_SUCCESS
5934 && pktin->type != SSH1_SMSG_FAILURE) {
5935 bombout(("Protocol confusion"));
5937 } else if (pktin->type == SSH1_SMSG_FAILURE) {
5938 c_write_str(ssh, "Server refused to allocate pty\r\n");
5939 ssh->editing = ssh->echoing = 1;
5941 logeventf(ssh, "Allocated pty (ospeed %dbps, ispeed %dbps)",
5942 ssh->ospeed, ssh->ispeed);
5943 ssh->got_pty = TRUE;
5946 ssh->editing = ssh->echoing = 1;
5949 if (conf_get_int(ssh->conf, CONF_compression)) {
5950 send_packet(ssh, SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END);
5954 if (pktin->type != SSH1_SMSG_SUCCESS
5955 && pktin->type != SSH1_SMSG_FAILURE) {
5956 bombout(("Protocol confusion"));
5958 } else if (pktin->type == SSH1_SMSG_FAILURE) {
5959 c_write_str(ssh, "Server refused to compress\r\n");
5961 logevent("Started compression");
5962 ssh->v1_compressing = TRUE;
5963 ssh->cs_comp_ctx = zlib_compress_init();
5964 logevent("Initialised zlib (RFC1950) compression");
5965 ssh->sc_comp_ctx = zlib_decompress_init();
5966 logevent("Initialised zlib (RFC1950) decompression");
5970 * Start the shell or command.
5972 * Special case: if the first-choice command is an SSH-2
5973 * subsystem (hence not usable here) and the second choice
5974 * exists, we fall straight back to that.
5977 char *cmd = conf_get_str(ssh->conf, CONF_remote_cmd);
5979 if (conf_get_int(ssh->conf, CONF_ssh_subsys) &&
5980 conf_get_str(ssh->conf, CONF_remote_cmd2)) {
5981 cmd = conf_get_str(ssh->conf, CONF_remote_cmd2);
5982 ssh->fallback_cmd = TRUE;
5985 send_packet(ssh, SSH1_CMSG_EXEC_CMD, PKT_STR, cmd, PKT_END);
5987 send_packet(ssh, SSH1_CMSG_EXEC_SHELL, PKT_END);
5988 logevent("Started session");
5991 ssh->state = SSH_STATE_SESSION;
5992 if (ssh->size_needed)
5993 ssh_size(ssh, ssh->term_width, ssh->term_height);
5994 if (ssh->eof_needed)
5995 ssh_special(ssh, TS_EOF);
5998 ldisc_echoedit_update(ssh->ldisc); /* cause ldisc to notice changes */
6000 ssh->channels = newtree234(ssh_channelcmp);
6004 * By this point, most incoming packets are already being
6005 * handled by the dispatch table, and we need only pay
6006 * attention to the unusual ones.
6011 if (pktin->type == SSH1_SMSG_SUCCESS) {
6012 /* may be from EXEC_SHELL on some servers */
6013 } else if (pktin->type == SSH1_SMSG_FAILURE) {
6014 /* may be from EXEC_SHELL on some servers
6015 * if no pty is available or in other odd cases. Ignore */
6017 bombout(("Strange packet received: type %d", pktin->type));
6022 int len = min(inlen, 512);
6023 send_packet(ssh, SSH1_CMSG_STDIN_DATA,
6024 PKT_INT, len, PKT_DATA, in, len,
6036 * Handle the top-level SSH-2 protocol.
6038 static void ssh1_msg_debug(Ssh ssh, struct Packet *pktin)
6043 ssh_pkt_getstring(pktin, &msg, &msglen);
6044 logeventf(ssh, "Remote debug message: %.*s", msglen, msg);
6047 static void ssh1_msg_disconnect(Ssh ssh, struct Packet *pktin)
6049 /* log reason code in disconnect message */
6053 ssh_pkt_getstring(pktin, &msg, &msglen);
6054 bombout(("Server sent disconnect message:\n\"%.*s\"", msglen, msg));
6057 static void ssh_msg_ignore(Ssh ssh, struct Packet *pktin)
6059 /* Do nothing, because we're ignoring it! Duhh. */
6062 static void ssh1_protocol_setup(Ssh ssh)
6067 * Most messages are handled by the coroutines.
6069 for (i = 0; i < 256; i++)
6070 ssh->packet_dispatch[i] = NULL;
6073 * These special message types we install handlers for.
6075 ssh->packet_dispatch[SSH1_MSG_DISCONNECT] = ssh1_msg_disconnect;
6076 ssh->packet_dispatch[SSH1_MSG_IGNORE] = ssh_msg_ignore;
6077 ssh->packet_dispatch[SSH1_MSG_DEBUG] = ssh1_msg_debug;
6080 static void ssh1_protocol(Ssh ssh, const void *vin, int inlen,
6081 struct Packet *pktin)
6083 const unsigned char *in = (const unsigned char *)vin;
6084 if (ssh->state == SSH_STATE_CLOSED)
6087 if (pktin && ssh->packet_dispatch[pktin->type]) {
6088 ssh->packet_dispatch[pktin->type](ssh, pktin);
6092 if (!ssh->protocol_initial_phase_done) {
6093 if (do_ssh1_login(ssh, in, inlen, pktin))
6094 ssh->protocol_initial_phase_done = TRUE;
6099 do_ssh1_connection(ssh, in, inlen, pktin);
6103 * Utility routines for decoding comma-separated strings in KEXINIT.
6105 static int first_in_commasep_string(char const *needle, char const *haystack,
6109 if (!needle || !haystack) /* protect against null pointers */
6111 needlen = strlen(needle);
6113 if (haylen >= needlen && /* haystack is long enough */
6114 !memcmp(needle, haystack, needlen) && /* initial match */
6115 (haylen == needlen || haystack[needlen] == ',')
6116 /* either , or EOS follows */
6122 static int in_commasep_string(char const *needle, char const *haystack,
6127 if (!needle || !haystack) /* protect against null pointers */
6130 * Is it at the start of the string?
6132 if (first_in_commasep_string(needle, haystack, haylen))
6135 * If not, search for the next comma and resume after that.
6136 * If no comma found, terminate.
6138 p = memchr(haystack, ',', haylen);
6140 /* + 1 to skip over comma */
6141 return in_commasep_string(needle, p + 1, haylen - (p + 1 - haystack));
6145 * Add a value to the comma-separated string at the end of the packet.
6147 static void ssh2_pkt_addstring_commasep(struct Packet *pkt, const char *data)
6149 if (pkt->length - pkt->savedpos > 0)
6150 ssh_pkt_addstring_str(pkt, ",");
6151 ssh_pkt_addstring_str(pkt, data);
6156 * SSH-2 key derivation (RFC 4253 section 7.2).
6158 static unsigned char *ssh2_mkkey(Ssh ssh, Bignum K, unsigned char *H,
6159 char chr, int keylen)
6161 const struct ssh_hash *h = ssh->kex->hash;
6169 /* Round up to the next multiple of hash length. */
6170 keylen_padded = ((keylen + h->hlen - 1) / h->hlen) * h->hlen;
6172 key = snewn(keylen_padded, unsigned char);
6174 /* First hlen bytes. */
6176 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
6177 hash_mpint(h, s, K);
6178 h->bytes(s, H, h->hlen);
6179 h->bytes(s, &chr, 1);
6180 h->bytes(s, ssh->v2_session_id, ssh->v2_session_id_len);
6183 /* Subsequent blocks of hlen bytes. */
6184 if (keylen_padded > h->hlen) {
6188 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
6189 hash_mpint(h, s, K);
6190 h->bytes(s, H, h->hlen);
6192 for (offset = h->hlen; offset < keylen_padded; offset += h->hlen) {
6193 h->bytes(s, key + offset - h->hlen, h->hlen);
6195 h->final(s2, key + offset);
6201 /* Now clear any extra bytes of key material beyond the length
6202 * we're officially returning, because the caller won't know to
6204 if (keylen_padded > keylen)
6205 smemclr(key + keylen, keylen_padded - keylen);
6211 * Structure for constructing KEXINIT algorithm lists.
6213 #define MAXKEXLIST 16
6214 struct kexinit_algorithm {
6218 const struct ssh_kex *kex;
6221 const struct ssh_signkey *hostkey;
6223 const struct ssh2_cipher *cipher;
6227 const struct ssh_mac *mac;
6230 const struct ssh_compress *comp;
6235 * Find a slot in a KEXINIT algorithm list to use for a new algorithm.
6236 * If the algorithm is already in the list, return a pointer to its
6237 * entry, otherwise return an entry from the end of the list.
6238 * This assumes that every time a particular name is passed in, it
6239 * comes from the same string constant. If this isn't true, this
6240 * function may need to be rewritten to use strcmp() instead.
6242 static struct kexinit_algorithm *ssh2_kexinit_addalg(struct kexinit_algorithm
6243 *list, const char *name)
6247 for (i = 0; i < MAXKEXLIST; i++)
6248 if (list[i].name == NULL || list[i].name == name) {
6249 list[i].name = name;
6252 assert(!"No space in KEXINIT list");
6257 * Handle the SSH-2 transport layer.
6259 static void do_ssh2_transport(Ssh ssh, const void *vin, int inlen,
6260 struct Packet *pktin)
6262 const unsigned char *in = (const unsigned char *)vin;
6264 KEXLIST_KEX, KEXLIST_HOSTKEY, KEXLIST_CSCIPHER, KEXLIST_SCCIPHER,
6265 KEXLIST_CSMAC, KEXLIST_SCMAC, KEXLIST_CSCOMP, KEXLIST_SCCOMP,
6268 const char * kexlist_descr[NKEXLIST] = {
6269 "key exchange algorithm", "host key algorithm",
6270 "client-to-server cipher", "server-to-client cipher",
6271 "client-to-server MAC", "server-to-client MAC",
6272 "client-to-server compression method",
6273 "server-to-client compression method" };
6274 struct do_ssh2_transport_state {
6276 int nbits, pbits, warn_kex, warn_cscipher, warn_sccipher;
6277 Bignum p, g, e, f, K;
6280 int kex_init_value, kex_reply_value;
6281 const struct ssh_mac **maclist;
6283 const struct ssh2_cipher *cscipher_tobe;
6284 const struct ssh2_cipher *sccipher_tobe;
6285 const struct ssh_mac *csmac_tobe;
6286 const struct ssh_mac *scmac_tobe;
6287 int csmac_etm_tobe, scmac_etm_tobe;
6288 const struct ssh_compress *cscomp_tobe;
6289 const struct ssh_compress *sccomp_tobe;
6290 char *hostkeydata, *sigdata, *rsakeydata, *keystr, *fingerprint;
6291 int hostkeylen, siglen, rsakeylen;
6292 void *hkey; /* actual host key */
6293 void *rsakey; /* for RSA kex */
6294 void *eckey; /* for ECDH kex */
6295 unsigned char exchange_hash[SSH2_KEX_MAX_HASH_LEN];
6296 int n_preferred_kex;
6297 const struct ssh_kexes *preferred_kex[KEX_MAX];
6298 int n_preferred_ciphers;
6299 const struct ssh2_ciphers *preferred_ciphers[CIPHER_MAX];
6300 const struct ssh_compress *preferred_comp;
6301 int userauth_succeeded; /* for delayed compression */
6302 int pending_compression;
6303 int got_session_id, activated_authconn;
6304 struct Packet *pktout;
6308 struct kexinit_algorithm kexlists[NKEXLIST][MAXKEXLIST];
6310 crState(do_ssh2_transport_state);
6312 assert(!ssh->bare_connection);
6316 s->cscipher_tobe = s->sccipher_tobe = NULL;
6317 s->csmac_tobe = s->scmac_tobe = NULL;
6318 s->cscomp_tobe = s->sccomp_tobe = NULL;
6320 s->got_session_id = s->activated_authconn = FALSE;
6321 s->userauth_succeeded = FALSE;
6322 s->pending_compression = FALSE;
6325 * Be prepared to work around the buggy MAC problem.
6327 if (ssh->remote_bugs & BUG_SSH2_HMAC)
6328 s->maclist = buggymacs, s->nmacs = lenof(buggymacs);
6330 s->maclist = macs, s->nmacs = lenof(macs);
6333 ssh->pkt_kctx = SSH2_PKTCTX_NOKEX;
6336 struct kexinit_algorithm *alg;
6339 * Set up the preferred key exchange. (NULL => warn below here)
6341 s->n_preferred_kex = 0;
6342 for (i = 0; i < KEX_MAX; i++) {
6343 switch (conf_get_int_int(ssh->conf, CONF_ssh_kexlist, i)) {
6345 s->preferred_kex[s->n_preferred_kex++] =
6346 &ssh_diffiehellman_gex;
6349 s->preferred_kex[s->n_preferred_kex++] =
6350 &ssh_diffiehellman_group14;
6353 s->preferred_kex[s->n_preferred_kex++] =
6354 &ssh_diffiehellman_group1;
6357 s->preferred_kex[s->n_preferred_kex++] =
6361 s->preferred_kex[s->n_preferred_kex++] =
6365 /* Flag for later. Don't bother if it's the last in
6367 if (i < KEX_MAX - 1) {
6368 s->preferred_kex[s->n_preferred_kex++] = NULL;
6375 * Set up the preferred ciphers. (NULL => warn below here)
6377 s->n_preferred_ciphers = 0;
6378 for (i = 0; i < CIPHER_MAX; i++) {
6379 switch (conf_get_int_int(ssh->conf, CONF_ssh_cipherlist, i)) {
6380 case CIPHER_BLOWFISH:
6381 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_blowfish;
6384 if (conf_get_int(ssh->conf, CONF_ssh2_des_cbc)) {
6385 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_des;
6389 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_3des;
6392 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_aes;
6394 case CIPHER_ARCFOUR:
6395 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_arcfour;
6397 case CIPHER_CHACHA20:
6398 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_ccp;
6401 /* Flag for later. Don't bother if it's the last in
6403 if (i < CIPHER_MAX - 1) {
6404 s->preferred_ciphers[s->n_preferred_ciphers++] = NULL;
6411 * Set up preferred compression.
6413 if (conf_get_int(ssh->conf, CONF_compression))
6414 s->preferred_comp = &ssh_zlib;
6416 s->preferred_comp = &ssh_comp_none;
6419 * Enable queueing of outgoing auth- or connection-layer
6420 * packets while we are in the middle of a key exchange.
6422 ssh->queueing = TRUE;
6425 * Flag that KEX is in progress.
6427 ssh->kex_in_progress = TRUE;
6429 for (i = 0; i < NKEXLIST; i++)
6430 for (j = 0; j < MAXKEXLIST; j++)
6431 s->kexlists[i][j].name = NULL;
6432 /* List key exchange algorithms. */
6434 for (i = 0; i < s->n_preferred_kex; i++) {
6435 const struct ssh_kexes *k = s->preferred_kex[i];
6436 if (!k) warn = TRUE;
6437 else for (j = 0; j < k->nkexes; j++) {
6438 alg = ssh2_kexinit_addalg(s->kexlists[KEXLIST_KEX],
6440 alg->u.kex.kex = k->list[j];
6441 alg->u.kex.warn = warn;
6444 /* List server host key algorithms. */
6445 if (!s->got_session_id) {
6447 * In the first key exchange, we list all the algorithms
6448 * we're prepared to cope with, but prefer those algorithms
6449 * for which we have a host key for this host.
6451 for (i = 0; i < lenof(hostkey_algs); i++) {
6452 if (have_ssh_host_key(ssh->savedhost, ssh->savedport,
6453 hostkey_algs[i]->keytype)) {
6454 alg = ssh2_kexinit_addalg(s->kexlists[KEXLIST_HOSTKEY],
6455 hostkey_algs[i]->name);
6456 alg->u.hostkey = hostkey_algs[i];
6459 for (i = 0; i < lenof(hostkey_algs); i++) {
6460 alg = ssh2_kexinit_addalg(s->kexlists[KEXLIST_HOSTKEY],
6461 hostkey_algs[i]->name);
6462 alg->u.hostkey = hostkey_algs[i];
6466 * In subsequent key exchanges, we list only the kex
6467 * algorithm that was selected in the first key exchange,
6468 * so that we keep getting the same host key and hence
6469 * don't have to interrupt the user's session to ask for
6473 alg = ssh2_kexinit_addalg(s->kexlists[KEXLIST_HOSTKEY],
6474 ssh->hostkey->name);
6475 alg->u.hostkey = ssh->hostkey;
6477 /* List encryption algorithms (client->server then server->client). */
6478 for (k = KEXLIST_CSCIPHER; k <= KEXLIST_SCCIPHER; k++) {
6481 alg = ssh2_kexinit_addalg(s->kexlists[k], "none");
6482 alg->u.cipher.cipher = NULL;
6483 alg->u.cipher.warn = warn;
6484 #endif /* FUZZING */
6485 for (i = 0; i < s->n_preferred_ciphers; i++) {
6486 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
6487 if (!c) warn = TRUE;
6488 else for (j = 0; j < c->nciphers; j++) {
6489 alg = ssh2_kexinit_addalg(s->kexlists[k],
6491 alg->u.cipher.cipher = c->list[j];
6492 alg->u.cipher.warn = warn;
6496 /* List MAC algorithms (client->server then server->client). */
6497 for (j = KEXLIST_CSMAC; j <= KEXLIST_SCMAC; j++) {
6499 alg = ssh2_kexinit_addalg(s->kexlists[j], "none");
6500 alg->u.mac.mac = NULL;
6501 alg->u.mac.etm = FALSE;
6502 #endif /* FUZZING */
6503 for (i = 0; i < s->nmacs; i++) {
6504 alg = ssh2_kexinit_addalg(s->kexlists[j], s->maclist[i]->name);
6505 alg->u.mac.mac = s->maclist[i];
6506 alg->u.mac.etm = FALSE;
6508 for (i = 0; i < s->nmacs; i++)
6509 /* For each MAC, there may also be an ETM version,
6510 * which we list second. */
6511 if (s->maclist[i]->etm_name) {
6512 alg = ssh2_kexinit_addalg(s->kexlists[j],
6513 s->maclist[i]->etm_name);
6514 alg->u.mac.mac = s->maclist[i];
6515 alg->u.mac.etm = TRUE;
6518 /* List client->server compression algorithms,
6519 * then server->client compression algorithms. (We use the
6520 * same set twice.) */
6521 for (j = KEXLIST_CSCOMP; j <= KEXLIST_SCCOMP; j++) {
6522 assert(lenof(compressions) > 1);
6523 /* Prefer non-delayed versions */
6524 alg = ssh2_kexinit_addalg(s->kexlists[j], s->preferred_comp->name);
6525 alg->u.comp = s->preferred_comp;
6526 /* We don't even list delayed versions of algorithms until
6527 * they're allowed to be used, to avoid a race. See the end of
6529 if (s->userauth_succeeded && s->preferred_comp->delayed_name) {
6530 alg = ssh2_kexinit_addalg(s->kexlists[j],
6531 s->preferred_comp->delayed_name);
6532 alg->u.comp = s->preferred_comp;
6534 for (i = 0; i < lenof(compressions); i++) {
6535 const struct ssh_compress *c = compressions[i];
6536 alg = ssh2_kexinit_addalg(s->kexlists[j], c->name);
6538 if (s->userauth_succeeded && c->delayed_name) {
6539 alg = ssh2_kexinit_addalg(s->kexlists[j], c->delayed_name);
6545 * Construct and send our key exchange packet.
6547 s->pktout = ssh2_pkt_init(SSH2_MSG_KEXINIT);
6548 for (i = 0; i < 16; i++)
6549 ssh2_pkt_addbyte(s->pktout, (unsigned char) random_byte());
6550 for (i = 0; i < NKEXLIST; i++) {
6551 ssh2_pkt_addstring_start(s->pktout);
6552 for (j = 0; j < MAXKEXLIST; j++) {
6553 if (s->kexlists[i][j].name == NULL) break;
6554 ssh2_pkt_addstring_commasep(s->pktout, s->kexlists[i][j].name);
6557 /* List client->server languages. Empty list. */
6558 ssh2_pkt_addstring_start(s->pktout);
6559 /* List server->client languages. Empty list. */
6560 ssh2_pkt_addstring_start(s->pktout);
6561 /* First KEX packet does _not_ follow, because we're not that brave. */
6562 ssh2_pkt_addbool(s->pktout, FALSE);
6564 ssh2_pkt_adduint32(s->pktout, 0);
6567 s->our_kexinitlen = s->pktout->length - 5;
6568 s->our_kexinit = snewn(s->our_kexinitlen, unsigned char);
6569 memcpy(s->our_kexinit, s->pktout->data + 5, s->our_kexinitlen);
6571 ssh2_pkt_send_noqueue(ssh, s->pktout);
6574 crWaitUntilV(pktin);
6577 * Now examine the other side's KEXINIT to see what we're up
6584 if (pktin->type != SSH2_MSG_KEXINIT) {
6585 bombout(("expected key exchange packet from server"));
6589 ssh->hostkey = NULL;
6590 s->cscipher_tobe = NULL;
6591 s->sccipher_tobe = NULL;
6592 s->csmac_tobe = NULL;
6593 s->scmac_tobe = NULL;
6594 s->cscomp_tobe = NULL;
6595 s->sccomp_tobe = NULL;
6596 s->warn_kex = s->warn_cscipher = s->warn_sccipher = FALSE;
6598 pktin->savedpos += 16; /* skip garbage cookie */
6601 for (i = 0; i < NKEXLIST; i++) {
6602 ssh_pkt_getstring(pktin, &str, &len);
6604 bombout(("KEXINIT packet was incomplete"));
6608 /* If we've already selected a cipher which requires a
6609 * particular MAC, then just select that, and don't even
6610 * bother looking through the server's KEXINIT string for
6612 if (i == KEXLIST_CSMAC && s->cscipher_tobe &&
6613 s->cscipher_tobe->required_mac) {
6614 s->csmac_tobe = s->cscipher_tobe->required_mac;
6615 s->csmac_etm_tobe = !!(s->csmac_tobe->etm_name);
6618 if (i == KEXLIST_SCMAC && s->sccipher_tobe &&
6619 s->sccipher_tobe->required_mac) {
6620 s->scmac_tobe = s->sccipher_tobe->required_mac;
6621 s->scmac_etm_tobe = !!(s->scmac_tobe->etm_name);
6625 for (j = 0; j < MAXKEXLIST; j++) {
6626 struct kexinit_algorithm *alg = &s->kexlists[i][j];
6627 if (alg->name == NULL) break;
6628 if (in_commasep_string(alg->name, str, len)) {
6629 /* We've found a matching algorithm. */
6630 if (i == KEXLIST_KEX || i == KEXLIST_HOSTKEY) {
6631 /* Check if we might need to ignore first kex pkt */
6633 !first_in_commasep_string(alg->name, str, len))
6636 if (i == KEXLIST_KEX) {
6637 ssh->kex = alg->u.kex.kex;
6638 s->warn_kex = alg->u.kex.warn;
6639 } else if (i == KEXLIST_HOSTKEY) {
6640 ssh->hostkey = alg->u.hostkey;
6641 } else if (i == KEXLIST_CSCIPHER) {
6642 s->cscipher_tobe = alg->u.cipher.cipher;
6643 s->warn_cscipher = alg->u.cipher.warn;
6644 } else if (i == KEXLIST_SCCIPHER) {
6645 s->sccipher_tobe = alg->u.cipher.cipher;
6646 s->warn_sccipher = alg->u.cipher.warn;
6647 } else if (i == KEXLIST_CSMAC) {
6648 s->csmac_tobe = alg->u.mac.mac;
6649 s->csmac_etm_tobe = alg->u.mac.etm;
6650 } else if (i == KEXLIST_SCMAC) {
6651 s->scmac_tobe = alg->u.mac.mac;
6652 s->scmac_etm_tobe = alg->u.mac.etm;
6653 } else if (i == KEXLIST_CSCOMP) {
6654 s->cscomp_tobe = alg->u.comp;
6655 } else if (i == KEXLIST_SCCOMP) {
6656 s->sccomp_tobe = alg->u.comp;
6660 if ((i == KEXLIST_CSCOMP || i == KEXLIST_SCCOMP) &&
6661 in_commasep_string(alg->u.comp->delayed_name, str, len))
6662 s->pending_compression = TRUE; /* try this later */
6664 bombout(("Couldn't agree a %s ((available: %.*s)",
6665 kexlist_descr[i], len, str));
6670 if (s->pending_compression) {
6671 logevent("Server supports delayed compression; "
6672 "will try this later");
6674 ssh_pkt_getstring(pktin, &str, &len); /* client->server language */
6675 ssh_pkt_getstring(pktin, &str, &len); /* server->client language */
6676 s->ignorepkt = ssh2_pkt_getbool(pktin) && !s->guessok;
6678 ssh->exhash = ssh->kex->hash->init();
6679 hash_string(ssh->kex->hash, ssh->exhash, ssh->v_c, strlen(ssh->v_c));
6680 hash_string(ssh->kex->hash, ssh->exhash, ssh->v_s, strlen(ssh->v_s));
6681 hash_string(ssh->kex->hash, ssh->exhash,
6682 s->our_kexinit, s->our_kexinitlen);
6683 sfree(s->our_kexinit);
6684 /* Include the type byte in the hash of server's KEXINIT */
6685 hash_string(ssh->kex->hash, ssh->exhash,
6686 pktin->body - 1, pktin->length + 1);
6689 ssh_set_frozen(ssh, 1);
6690 s->dlgret = askalg(ssh->frontend, "key-exchange algorithm",
6692 ssh_dialog_callback, ssh);
6693 if (s->dlgret < 0) {
6697 bombout(("Unexpected data from server while"
6698 " waiting for user response"));
6701 } while (pktin || inlen > 0);
6702 s->dlgret = ssh->user_response;
6704 ssh_set_frozen(ssh, 0);
6705 if (s->dlgret == 0) {
6706 ssh_disconnect(ssh, "User aborted at kex warning", NULL,
6712 if (s->warn_cscipher) {
6713 ssh_set_frozen(ssh, 1);
6714 s->dlgret = askalg(ssh->frontend,
6715 "client-to-server cipher",
6716 s->cscipher_tobe->name,
6717 ssh_dialog_callback, ssh);
6718 if (s->dlgret < 0) {
6722 bombout(("Unexpected data from server while"
6723 " waiting for user response"));
6726 } while (pktin || inlen > 0);
6727 s->dlgret = ssh->user_response;
6729 ssh_set_frozen(ssh, 0);
6730 if (s->dlgret == 0) {
6731 ssh_disconnect(ssh, "User aborted at cipher warning", NULL,
6737 if (s->warn_sccipher) {
6738 ssh_set_frozen(ssh, 1);
6739 s->dlgret = askalg(ssh->frontend,
6740 "server-to-client cipher",
6741 s->sccipher_tobe->name,
6742 ssh_dialog_callback, ssh);
6743 if (s->dlgret < 0) {
6747 bombout(("Unexpected data from server while"
6748 " waiting for user response"));
6751 } while (pktin || inlen > 0);
6752 s->dlgret = ssh->user_response;
6754 ssh_set_frozen(ssh, 0);
6755 if (s->dlgret == 0) {
6756 ssh_disconnect(ssh, "User aborted at cipher warning", NULL,
6762 if (s->ignorepkt) /* first_kex_packet_follows */
6763 crWaitUntilV(pktin); /* Ignore packet */
6766 if (ssh->kex->main_type == KEXTYPE_DH) {
6768 * Work out the number of bits of key we will need from the
6769 * key exchange. We start with the maximum key length of
6775 csbits = s->cscipher_tobe ? s->cscipher_tobe->real_keybits : 0;
6776 scbits = s->sccipher_tobe ? s->sccipher_tobe->real_keybits : 0;
6777 s->nbits = (csbits > scbits ? csbits : scbits);
6779 /* The keys only have hlen-bit entropy, since they're based on
6780 * a hash. So cap the key size at hlen bits. */
6781 if (s->nbits > ssh->kex->hash->hlen * 8)
6782 s->nbits = ssh->kex->hash->hlen * 8;
6785 * If we're doing Diffie-Hellman group exchange, start by
6786 * requesting a group.
6788 if (dh_is_gex(ssh->kex)) {
6789 logevent("Doing Diffie-Hellman group exchange");
6790 ssh->pkt_kctx = SSH2_PKTCTX_DHGEX;
6792 * Work out how big a DH group we will need to allow that
6795 s->pbits = 512 << ((s->nbits - 1) / 64);
6796 if (s->pbits < DH_MIN_SIZE)
6797 s->pbits = DH_MIN_SIZE;
6798 if (s->pbits > DH_MAX_SIZE)
6799 s->pbits = DH_MAX_SIZE;
6800 if ((ssh->remote_bugs & BUG_SSH2_OLDGEX)) {
6801 s->pktout = ssh2_pkt_init(SSH2_MSG_KEX_DH_GEX_REQUEST_OLD);
6802 ssh2_pkt_adduint32(s->pktout, s->pbits);
6804 s->pktout = ssh2_pkt_init(SSH2_MSG_KEX_DH_GEX_REQUEST);
6805 ssh2_pkt_adduint32(s->pktout, DH_MIN_SIZE);
6806 ssh2_pkt_adduint32(s->pktout, s->pbits);
6807 ssh2_pkt_adduint32(s->pktout, DH_MAX_SIZE);
6809 ssh2_pkt_send_noqueue(ssh, s->pktout);
6811 crWaitUntilV(pktin);
6812 if (pktin->type != SSH2_MSG_KEX_DH_GEX_GROUP) {
6813 bombout(("expected key exchange group packet from server"));
6816 s->p = ssh2_pkt_getmp(pktin);
6817 s->g = ssh2_pkt_getmp(pktin);
6818 if (!s->p || !s->g) {
6819 bombout(("unable to read mp-ints from incoming group packet"));
6822 ssh->kex_ctx = dh_setup_gex(s->p, s->g);
6823 s->kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT;
6824 s->kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY;
6826 ssh->pkt_kctx = SSH2_PKTCTX_DHGROUP;
6827 ssh->kex_ctx = dh_setup_group(ssh->kex);
6828 s->kex_init_value = SSH2_MSG_KEXDH_INIT;
6829 s->kex_reply_value = SSH2_MSG_KEXDH_REPLY;
6830 logeventf(ssh, "Using Diffie-Hellman with standard group \"%s\"",
6831 ssh->kex->groupname);
6834 logeventf(ssh, "Doing Diffie-Hellman key exchange with hash %s",
6835 ssh->kex->hash->text_name);
6837 * Now generate and send e for Diffie-Hellman.
6839 set_busy_status(ssh->frontend, BUSY_CPU); /* this can take a while */
6840 s->e = dh_create_e(ssh->kex_ctx, s->nbits * 2);
6841 s->pktout = ssh2_pkt_init(s->kex_init_value);
6842 ssh2_pkt_addmp(s->pktout, s->e);
6843 ssh2_pkt_send_noqueue(ssh, s->pktout);
6845 set_busy_status(ssh->frontend, BUSY_WAITING); /* wait for server */
6846 crWaitUntilV(pktin);
6847 if (pktin->type != s->kex_reply_value) {
6848 bombout(("expected key exchange reply packet from server"));
6851 set_busy_status(ssh->frontend, BUSY_CPU); /* cogitate */
6852 ssh_pkt_getstring(pktin, &s->hostkeydata, &s->hostkeylen);
6853 if (!s->hostkeydata) {
6854 bombout(("unable to parse key exchange reply packet"));
6857 s->hkey = ssh->hostkey->newkey(ssh->hostkey,
6858 s->hostkeydata, s->hostkeylen);
6859 s->f = ssh2_pkt_getmp(pktin);
6861 bombout(("unable to parse key exchange reply packet"));
6864 ssh_pkt_getstring(pktin, &s->sigdata, &s->siglen);
6866 bombout(("unable to parse key exchange reply packet"));
6871 const char *err = dh_validate_f(ssh->kex_ctx, s->f);
6873 bombout(("key exchange reply failed validation: %s", err));
6877 s->K = dh_find_K(ssh->kex_ctx, s->f);
6879 /* We assume everything from now on will be quick, and it might
6880 * involve user interaction. */
6881 set_busy_status(ssh->frontend, BUSY_NOT);
6883 hash_string(ssh->kex->hash, ssh->exhash, s->hostkeydata, s->hostkeylen);
6884 if (dh_is_gex(ssh->kex)) {
6885 if (!(ssh->remote_bugs & BUG_SSH2_OLDGEX))
6886 hash_uint32(ssh->kex->hash, ssh->exhash, DH_MIN_SIZE);
6887 hash_uint32(ssh->kex->hash, ssh->exhash, s->pbits);
6888 if (!(ssh->remote_bugs & BUG_SSH2_OLDGEX))
6889 hash_uint32(ssh->kex->hash, ssh->exhash, DH_MAX_SIZE);
6890 hash_mpint(ssh->kex->hash, ssh->exhash, s->p);
6891 hash_mpint(ssh->kex->hash, ssh->exhash, s->g);
6893 hash_mpint(ssh->kex->hash, ssh->exhash, s->e);
6894 hash_mpint(ssh->kex->hash, ssh->exhash, s->f);
6896 dh_cleanup(ssh->kex_ctx);
6898 if (dh_is_gex(ssh->kex)) {
6902 } else if (ssh->kex->main_type == KEXTYPE_ECDH) {
6904 logeventf(ssh, "Doing ECDH key exchange with curve %s and hash %s",
6905 ssh_ecdhkex_curve_textname(ssh->kex),
6906 ssh->kex->hash->text_name);
6907 ssh->pkt_kctx = SSH2_PKTCTX_ECDHKEX;
6909 s->eckey = ssh_ecdhkex_newkey(ssh->kex);
6911 bombout(("Unable to generate key for ECDH"));
6917 int publicPointLength;
6918 publicPoint = ssh_ecdhkex_getpublic(s->eckey, &publicPointLength);
6920 ssh_ecdhkex_freekey(s->eckey);
6921 bombout(("Unable to encode public key for ECDH"));
6924 s->pktout = ssh2_pkt_init(SSH2_MSG_KEX_ECDH_INIT);
6925 ssh2_pkt_addstring_start(s->pktout);
6926 ssh2_pkt_addstring_data(s->pktout, publicPoint, publicPointLength);
6930 ssh2_pkt_send_noqueue(ssh, s->pktout);
6932 crWaitUntilV(pktin);
6933 if (pktin->type != SSH2_MSG_KEX_ECDH_REPLY) {
6934 ssh_ecdhkex_freekey(s->eckey);
6935 bombout(("expected ECDH reply packet from server"));
6939 ssh_pkt_getstring(pktin, &s->hostkeydata, &s->hostkeylen);
6940 if (!s->hostkeydata) {
6941 bombout(("unable to parse ECDH reply packet"));
6944 hash_string(ssh->kex->hash, ssh->exhash, s->hostkeydata, s->hostkeylen);
6945 s->hkey = ssh->hostkey->newkey(ssh->hostkey,
6946 s->hostkeydata, s->hostkeylen);
6950 int publicPointLength;
6951 publicPoint = ssh_ecdhkex_getpublic(s->eckey, &publicPointLength);
6953 ssh_ecdhkex_freekey(s->eckey);
6954 bombout(("Unable to encode public key for ECDH hash"));
6957 hash_string(ssh->kex->hash, ssh->exhash,
6958 publicPoint, publicPointLength);
6965 ssh_pkt_getstring(pktin, &keydata, &keylen);
6967 bombout(("unable to parse ECDH reply packet"));
6970 hash_string(ssh->kex->hash, ssh->exhash, keydata, keylen);
6971 s->K = ssh_ecdhkex_getkey(s->eckey, keydata, keylen);
6973 ssh_ecdhkex_freekey(s->eckey);
6974 bombout(("point received in ECDH was not valid"));
6979 ssh_pkt_getstring(pktin, &s->sigdata, &s->siglen);
6981 bombout(("unable to parse key exchange reply packet"));
6985 ssh_ecdhkex_freekey(s->eckey);
6987 logeventf(ssh, "Doing RSA key exchange with hash %s",
6988 ssh->kex->hash->text_name);
6989 ssh->pkt_kctx = SSH2_PKTCTX_RSAKEX;
6991 * RSA key exchange. First expect a KEXRSA_PUBKEY packet
6994 crWaitUntilV(pktin);
6995 if (pktin->type != SSH2_MSG_KEXRSA_PUBKEY) {
6996 bombout(("expected RSA public key packet from server"));
7000 ssh_pkt_getstring(pktin, &s->hostkeydata, &s->hostkeylen);
7001 if (!s->hostkeydata) {
7002 bombout(("unable to parse RSA public key packet"));
7005 hash_string(ssh->kex->hash, ssh->exhash,
7006 s->hostkeydata, s->hostkeylen);
7007 s->hkey = ssh->hostkey->newkey(ssh->hostkey,
7008 s->hostkeydata, s->hostkeylen);
7012 ssh_pkt_getstring(pktin, &keydata, &s->rsakeylen);
7014 bombout(("unable to parse RSA public key packet"));
7017 s->rsakeydata = snewn(s->rsakeylen, char);
7018 memcpy(s->rsakeydata, keydata, s->rsakeylen);
7021 s->rsakey = ssh_rsakex_newkey(s->rsakeydata, s->rsakeylen);
7023 sfree(s->rsakeydata);
7024 bombout(("unable to parse RSA public key from server"));
7028 hash_string(ssh->kex->hash, ssh->exhash, s->rsakeydata, s->rsakeylen);
7031 * Next, set up a shared secret K, of precisely KLEN -
7032 * 2*HLEN - 49 bits, where KLEN is the bit length of the
7033 * RSA key modulus and HLEN is the bit length of the hash
7037 int klen = ssh_rsakex_klen(s->rsakey);
7038 int nbits = klen - (2*ssh->kex->hash->hlen*8 + 49);
7040 unsigned char *kstr1, *kstr2, *outstr;
7041 int kstr1len, kstr2len, outstrlen;
7043 s->K = bn_power_2(nbits - 1);
7045 for (i = 0; i < nbits; i++) {
7047 byte = random_byte();
7049 bignum_set_bit(s->K, i, (byte >> (i & 7)) & 1);
7053 * Encode this as an mpint.
7055 kstr1 = ssh2_mpint_fmt(s->K, &kstr1len);
7056 kstr2 = snewn(kstr2len = 4 + kstr1len, unsigned char);
7057 PUT_32BIT(kstr2, kstr1len);
7058 memcpy(kstr2 + 4, kstr1, kstr1len);
7061 * Encrypt it with the given RSA key.
7063 outstrlen = (klen + 7) / 8;
7064 outstr = snewn(outstrlen, unsigned char);
7065 ssh_rsakex_encrypt(ssh->kex->hash, kstr2, kstr2len,
7066 outstr, outstrlen, s->rsakey);
7069 * And send it off in a return packet.
7071 s->pktout = ssh2_pkt_init(SSH2_MSG_KEXRSA_SECRET);
7072 ssh2_pkt_addstring_start(s->pktout);
7073 ssh2_pkt_addstring_data(s->pktout, (char *)outstr, outstrlen);
7074 ssh2_pkt_send_noqueue(ssh, s->pktout);
7076 hash_string(ssh->kex->hash, ssh->exhash, outstr, outstrlen);
7083 ssh_rsakex_freekey(s->rsakey);
7085 crWaitUntilV(pktin);
7086 if (pktin->type != SSH2_MSG_KEXRSA_DONE) {
7087 sfree(s->rsakeydata);
7088 bombout(("expected signature packet from server"));
7092 ssh_pkt_getstring(pktin, &s->sigdata, &s->siglen);
7094 bombout(("unable to parse signature packet"));
7098 sfree(s->rsakeydata);
7101 hash_mpint(ssh->kex->hash, ssh->exhash, s->K);
7102 assert(ssh->kex->hash->hlen <= sizeof(s->exchange_hash));
7103 ssh->kex->hash->final(ssh->exhash, s->exchange_hash);
7105 ssh->kex_ctx = NULL;
7108 debug(("Exchange hash is:\n"));
7109 dmemdump(s->exchange_hash, ssh->kex->hash->hlen);
7113 bombout(("Server's host key is invalid"));
7117 if (!ssh->hostkey->verifysig(s->hkey, s->sigdata, s->siglen,
7118 (char *)s->exchange_hash,
7119 ssh->kex->hash->hlen)) {
7121 bombout(("Server's host key did not match the signature supplied"));
7126 s->keystr = ssh->hostkey->fmtkey(s->hkey);
7127 if (!s->got_session_id) {
7129 * Authenticate remote host: verify host key. (We've already
7130 * checked the signature of the exchange hash.)
7132 s->fingerprint = ssh2_fingerprint(ssh->hostkey, s->hkey);
7133 logevent("Host key fingerprint is:");
7134 logevent(s->fingerprint);
7135 /* First check against manually configured host keys. */
7136 s->dlgret = verify_ssh_manual_host_key(ssh, s->fingerprint,
7137 ssh->hostkey, s->hkey);
7138 if (s->dlgret == 0) { /* did not match */
7139 bombout(("Host key did not appear in manually configured list"));
7141 } else if (s->dlgret < 0) { /* none configured; use standard handling */
7142 ssh_set_frozen(ssh, 1);
7143 s->dlgret = verify_ssh_host_key(ssh->frontend,
7144 ssh->savedhost, ssh->savedport,
7145 ssh->hostkey->keytype, s->keystr,
7147 ssh_dialog_callback, ssh);
7151 if (s->dlgret < 0) {
7155 bombout(("Unexpected data from server while waiting"
7156 " for user host key response"));
7159 } while (pktin || inlen > 0);
7160 s->dlgret = ssh->user_response;
7162 ssh_set_frozen(ssh, 0);
7163 if (s->dlgret == 0) {
7164 ssh_disconnect(ssh, "Aborted at host key verification", NULL,
7169 sfree(s->fingerprint);
7171 * Save this host key, to check against the one presented in
7172 * subsequent rekeys.
7174 ssh->hostkey_str = s->keystr;
7177 * In a rekey, we never present an interactive host key
7178 * verification request to the user. Instead, we simply
7179 * enforce that the key we're seeing this time is identical to
7180 * the one we saw before.
7182 if (strcmp(ssh->hostkey_str, s->keystr)) {
7184 bombout(("Host key was different in repeat key exchange"));
7190 ssh->hostkey->freekey(s->hkey);
7193 * The exchange hash from the very first key exchange is also
7194 * the session id, used in session key construction and
7197 if (!s->got_session_id) {
7198 assert(sizeof(s->exchange_hash) <= sizeof(ssh->v2_session_id));
7199 memcpy(ssh->v2_session_id, s->exchange_hash,
7200 sizeof(s->exchange_hash));
7201 ssh->v2_session_id_len = ssh->kex->hash->hlen;
7202 assert(ssh->v2_session_id_len <= sizeof(ssh->v2_session_id));
7203 s->got_session_id = TRUE;
7207 * Send SSH2_MSG_NEWKEYS.
7209 s->pktout = ssh2_pkt_init(SSH2_MSG_NEWKEYS);
7210 ssh2_pkt_send_noqueue(ssh, s->pktout);
7211 ssh->outgoing_data_size = 0; /* start counting from here */
7214 * We've sent client NEWKEYS, so create and initialise
7215 * client-to-server session keys.
7217 if (ssh->cs_cipher_ctx)
7218 ssh->cscipher->free_context(ssh->cs_cipher_ctx);
7219 ssh->cscipher = s->cscipher_tobe;
7220 if (ssh->cscipher) ssh->cs_cipher_ctx = ssh->cscipher->make_context();
7222 if (ssh->cs_mac_ctx)
7223 ssh->csmac->free_context(ssh->cs_mac_ctx);
7224 ssh->csmac = s->csmac_tobe;
7225 ssh->csmac_etm = s->csmac_etm_tobe;
7227 ssh->cs_mac_ctx = ssh->csmac->make_context(ssh->cs_cipher_ctx);
7229 if (ssh->cs_comp_ctx)
7230 ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
7231 ssh->cscomp = s->cscomp_tobe;
7232 ssh->cs_comp_ctx = ssh->cscomp->compress_init();
7235 * Set IVs on client-to-server keys. Here we use the exchange
7236 * hash from the _first_ key exchange.
7238 if (ssh->cscipher) {
7241 key = ssh2_mkkey(ssh, s->K, s->exchange_hash, 'C',
7242 ssh->cscipher->padded_keybytes);
7243 ssh->cscipher->setkey(ssh->cs_cipher_ctx, key);
7244 smemclr(key, ssh->cscipher->padded_keybytes);
7247 key = ssh2_mkkey(ssh, s->K, s->exchange_hash, 'A',
7248 ssh->cscipher->blksize);
7249 ssh->cscipher->setiv(ssh->cs_cipher_ctx, key);
7250 smemclr(key, ssh->cscipher->blksize);
7256 key = ssh2_mkkey(ssh, s->K, s->exchange_hash, 'E',
7257 ssh->csmac->keylen);
7258 ssh->csmac->setkey(ssh->cs_mac_ctx, key);
7259 smemclr(key, ssh->csmac->keylen);
7264 logeventf(ssh, "Initialised %.200s client->server encryption",
7265 ssh->cscipher->text_name);
7267 logeventf(ssh, "Initialised %.200s client->server MAC algorithm%s%s",
7268 ssh->csmac->text_name,
7269 ssh->csmac_etm ? " (in ETM mode)" : "",
7270 ssh->cscipher->required_mac ? " (required by cipher)" : "");
7271 if (ssh->cscomp->text_name)
7272 logeventf(ssh, "Initialised %s compression",
7273 ssh->cscomp->text_name);
7276 * Now our end of the key exchange is complete, we can send all
7277 * our queued higher-layer packets.
7279 ssh->queueing = FALSE;
7280 ssh2_pkt_queuesend(ssh);
7283 * Expect SSH2_MSG_NEWKEYS from server.
7285 crWaitUntilV(pktin);
7286 if (pktin->type != SSH2_MSG_NEWKEYS) {
7287 bombout(("expected new-keys packet from server"));
7290 ssh->incoming_data_size = 0; /* start counting from here */
7293 * We've seen server NEWKEYS, so create and initialise
7294 * server-to-client session keys.
7296 if (ssh->sc_cipher_ctx)
7297 ssh->sccipher->free_context(ssh->sc_cipher_ctx);
7298 if (s->sccipher_tobe) {
7299 ssh->sccipher = s->sccipher_tobe;
7300 ssh->sc_cipher_ctx = ssh->sccipher->make_context();
7303 if (ssh->sc_mac_ctx)
7304 ssh->scmac->free_context(ssh->sc_mac_ctx);
7305 if (s->scmac_tobe) {
7306 ssh->scmac = s->scmac_tobe;
7307 ssh->scmac_etm = s->scmac_etm_tobe;
7308 ssh->sc_mac_ctx = ssh->scmac->make_context(ssh->sc_cipher_ctx);
7311 if (ssh->sc_comp_ctx)
7312 ssh->sccomp->decompress_cleanup(ssh->sc_comp_ctx);
7313 ssh->sccomp = s->sccomp_tobe;
7314 ssh->sc_comp_ctx = ssh->sccomp->decompress_init();
7317 * Set IVs on server-to-client keys. Here we use the exchange
7318 * hash from the _first_ key exchange.
7320 if (ssh->sccipher) {
7323 key = ssh2_mkkey(ssh, s->K, s->exchange_hash, 'D',
7324 ssh->sccipher->padded_keybytes);
7325 ssh->sccipher->setkey(ssh->sc_cipher_ctx, key);
7326 smemclr(key, ssh->sccipher->padded_keybytes);
7329 key = ssh2_mkkey(ssh, s->K, s->exchange_hash, 'B',
7330 ssh->sccipher->blksize);
7331 ssh->sccipher->setiv(ssh->sc_cipher_ctx, key);
7332 smemclr(key, ssh->sccipher->blksize);
7338 key = ssh2_mkkey(ssh, s->K, s->exchange_hash, 'F',
7339 ssh->scmac->keylen);
7340 ssh->scmac->setkey(ssh->sc_mac_ctx, key);
7341 smemclr(key, ssh->scmac->keylen);
7345 logeventf(ssh, "Initialised %.200s server->client encryption",
7346 ssh->sccipher->text_name);
7348 logeventf(ssh, "Initialised %.200s server->client MAC algorithm%s%s",
7349 ssh->scmac->text_name,
7350 ssh->scmac_etm ? " (in ETM mode)" : "",
7351 ssh->sccipher->required_mac ? " (required by cipher)" : "");
7352 if (ssh->sccomp->text_name)
7353 logeventf(ssh, "Initialised %s decompression",
7354 ssh->sccomp->text_name);
7357 * Free shared secret.
7362 * Key exchange is over. Loop straight back round if we have a
7363 * deferred rekey reason.
7365 if (ssh->deferred_rekey_reason) {
7366 logevent(ssh->deferred_rekey_reason);
7368 ssh->deferred_rekey_reason = NULL;
7369 goto begin_key_exchange;
7373 * Otherwise, schedule a timer for our next rekey.
7375 ssh->kex_in_progress = FALSE;
7376 ssh->last_rekey = GETTICKCOUNT();
7377 if (conf_get_int(ssh->conf, CONF_ssh_rekey_time) != 0)
7378 ssh->next_rekey = schedule_timer(conf_get_int(ssh->conf, CONF_ssh_rekey_time)*60*TICKSPERSEC,
7382 * Now we're encrypting. Begin returning 1 to the protocol main
7383 * function so that other things can run on top of the
7384 * transport. If we ever see a KEXINIT, we must go back to the
7387 * We _also_ go back to the start if we see pktin==NULL and
7388 * inlen negative, because this is a special signal meaning
7389 * `initiate client-driven rekey', and `in' contains a message
7390 * giving the reason for the rekey.
7392 * inlen==-1 means always initiate a rekey;
7393 * inlen==-2 means that userauth has completed successfully and
7394 * we should consider rekeying (for delayed compression).
7396 while (!((pktin && pktin->type == SSH2_MSG_KEXINIT) ||
7397 (!pktin && inlen < 0))) {
7399 if (!ssh->protocol_initial_phase_done) {
7400 ssh->protocol_initial_phase_done = TRUE;
7402 * Allow authconn to initialise itself.
7404 do_ssh2_authconn(ssh, NULL, 0, NULL);
7409 logevent("Server initiated key re-exchange");
7413 * authconn has seen a USERAUTH_SUCCEEDED. Time to enable
7414 * delayed compression, if it's available.
7416 * draft-miller-secsh-compression-delayed-00 says that you
7417 * negotiate delayed compression in the first key exchange, and
7418 * both sides start compressing when the server has sent
7419 * USERAUTH_SUCCESS. This has a race condition -- the server
7420 * can't know when the client has seen it, and thus which incoming
7421 * packets it should treat as compressed.
7423 * Instead, we do the initial key exchange without offering the
7424 * delayed methods, but note if the server offers them; when we
7425 * get here, if a delayed method was available that was higher
7426 * on our list than what we got, we initiate a rekey in which we
7427 * _do_ list the delayed methods (and hopefully get it as a
7428 * result). Subsequent rekeys will do the same.
7430 assert(!s->userauth_succeeded); /* should only happen once */
7431 s->userauth_succeeded = TRUE;
7432 if (!s->pending_compression)
7433 /* Can't see any point rekeying. */
7434 goto wait_for_rekey; /* this is utterly horrid */
7435 /* else fall through to rekey... */
7436 s->pending_compression = FALSE;
7439 * Now we've decided to rekey.
7441 * Special case: if the server bug is set that doesn't
7442 * allow rekeying, we give a different log message and
7443 * continue waiting. (If such a server _initiates_ a rekey,
7444 * we process it anyway!)
7446 if ((ssh->remote_bugs & BUG_SSH2_REKEY)) {
7447 logeventf(ssh, "Server bug prevents key re-exchange (%s)",
7449 /* Reset the counters, so that at least this message doesn't
7450 * hit the event log _too_ often. */
7451 ssh->outgoing_data_size = 0;
7452 ssh->incoming_data_size = 0;
7453 if (conf_get_int(ssh->conf, CONF_ssh_rekey_time) != 0) {
7455 schedule_timer(conf_get_int(ssh->conf, CONF_ssh_rekey_time)*60*TICKSPERSEC,
7458 goto wait_for_rekey; /* this is still utterly horrid */
7460 logeventf(ssh, "Initiating key re-exchange (%s)", (char *)in);
7463 goto begin_key_exchange;
7469 * Add data to an SSH-2 channel output buffer.
7471 static void ssh2_add_channel_data(struct ssh_channel *c, const char *buf,
7474 bufchain_add(&c->v.v2.outbuffer, buf, len);
7478 * Attempt to send data on an SSH-2 channel.
7480 static int ssh2_try_send(struct ssh_channel *c)
7483 struct Packet *pktout;
7486 while (c->v.v2.remwindow > 0 && bufchain_size(&c->v.v2.outbuffer) > 0) {
7489 bufchain_prefix(&c->v.v2.outbuffer, &data, &len);
7490 if ((unsigned)len > c->v.v2.remwindow)
7491 len = c->v.v2.remwindow;
7492 if ((unsigned)len > c->v.v2.remmaxpkt)
7493 len = c->v.v2.remmaxpkt;
7494 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_DATA);
7495 ssh2_pkt_adduint32(pktout, c->remoteid);
7496 ssh2_pkt_addstring_start(pktout);
7497 ssh2_pkt_addstring_data(pktout, data, len);
7498 ssh2_pkt_send(ssh, pktout);
7499 bufchain_consume(&c->v.v2.outbuffer, len);
7500 c->v.v2.remwindow -= len;
7504 * After having sent as much data as we can, return the amount
7507 ret = bufchain_size(&c->v.v2.outbuffer);
7510 * And if there's no data pending but we need to send an EOF, send
7513 if (!ret && c->pending_eof)
7514 ssh_channel_try_eof(c);
7519 static void ssh2_try_send_and_unthrottle(Ssh ssh, struct ssh_channel *c)
7522 if (c->closes & CLOSES_SENT_EOF)
7523 return; /* don't send on channels we've EOFed */
7524 bufsize = ssh2_try_send(c);
7527 case CHAN_MAINSESSION:
7528 /* stdin need not receive an unthrottle
7529 * notification since it will be polled */
7532 x11_unthrottle(c->u.x11.xconn);
7535 /* agent sockets are request/response and need no
7536 * buffer management */
7539 pfd_unthrottle(c->u.pfd.pf);
7545 static int ssh_is_simple(Ssh ssh)
7548 * We use the 'simple' variant of the SSH protocol if we're asked
7549 * to, except not if we're also doing connection-sharing (either
7550 * tunnelling our packets over an upstream or expecting to be
7551 * tunnelled over ourselves), since then the assumption that we
7552 * have only one channel to worry about is not true after all.
7554 return (conf_get_int(ssh->conf, CONF_ssh_simple) &&
7555 !ssh->bare_connection && !ssh->connshare);
7559 * Set up most of a new ssh_channel for SSH-2.
7561 static void ssh2_channel_init(struct ssh_channel *c)
7564 c->localid = alloc_channel_id(ssh);
7566 c->pending_eof = FALSE;
7567 c->throttling_conn = FALSE;
7568 c->v.v2.locwindow = c->v.v2.locmaxwin = c->v.v2.remlocwin =
7569 ssh_is_simple(ssh) ? OUR_V2_BIGWIN : OUR_V2_WINSIZE;
7570 c->v.v2.chanreq_head = NULL;
7571 c->v.v2.throttle_state = UNTHROTTLED;
7572 bufchain_init(&c->v.v2.outbuffer);
7576 * Construct the common parts of a CHANNEL_OPEN.
7578 static struct Packet *ssh2_chanopen_init(struct ssh_channel *c,
7581 struct Packet *pktout;
7583 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN);
7584 ssh2_pkt_addstring(pktout, type);
7585 ssh2_pkt_adduint32(pktout, c->localid);
7586 ssh2_pkt_adduint32(pktout, c->v.v2.locwindow);/* our window size */
7587 ssh2_pkt_adduint32(pktout, OUR_V2_MAXPKT); /* our max pkt size */
7592 * CHANNEL_FAILURE doesn't come with any indication of what message
7593 * caused it, so we have to keep track of the outstanding
7594 * CHANNEL_REQUESTs ourselves.
7596 static void ssh2_queue_chanreq_handler(struct ssh_channel *c,
7597 cchandler_fn_t handler, void *ctx)
7599 struct outstanding_channel_request *ocr =
7600 snew(struct outstanding_channel_request);
7602 assert(!(c->closes & (CLOSES_SENT_CLOSE | CLOSES_RCVD_CLOSE)));
7603 ocr->handler = handler;
7606 if (!c->v.v2.chanreq_head)
7607 c->v.v2.chanreq_head = ocr;
7609 c->v.v2.chanreq_tail->next = ocr;
7610 c->v.v2.chanreq_tail = ocr;
7614 * Construct the common parts of a CHANNEL_REQUEST. If handler is not
7615 * NULL then a reply will be requested and the handler will be called
7616 * when it arrives. The returned packet is ready to have any
7617 * request-specific data added and be sent. Note that if a handler is
7618 * provided, it's essential that the request actually be sent.
7620 * The handler will usually be passed the response packet in pktin. If
7621 * pktin is NULL, this means that no reply will ever be forthcoming
7622 * (e.g. because the entire connection is being destroyed, or because
7623 * the server initiated channel closure before we saw the response)
7624 * and the handler should free any storage it's holding.
7626 static struct Packet *ssh2_chanreq_init(struct ssh_channel *c,
7628 cchandler_fn_t handler, void *ctx)
7630 struct Packet *pktout;
7632 assert(!(c->closes & (CLOSES_SENT_CLOSE | CLOSES_RCVD_CLOSE)));
7633 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
7634 ssh2_pkt_adduint32(pktout, c->remoteid);
7635 ssh2_pkt_addstring(pktout, type);
7636 ssh2_pkt_addbool(pktout, handler != NULL);
7637 if (handler != NULL)
7638 ssh2_queue_chanreq_handler(c, handler, ctx);
7643 * Potentially enlarge the window on an SSH-2 channel.
7645 static void ssh2_handle_winadj_response(struct ssh_channel *, struct Packet *,
7647 static void ssh2_set_window(struct ssh_channel *c, int newwin)
7652 * Never send WINDOW_ADJUST for a channel that the remote side has
7653 * already sent EOF on; there's no point, since it won't be
7654 * sending any more data anyway. Ditto if _we've_ already sent
7657 if (c->closes & (CLOSES_RCVD_EOF | CLOSES_SENT_CLOSE))
7661 * Also, never widen the window for an X11 channel when we're
7662 * still waiting to see its initial auth and may yet hand it off
7665 if (c->type == CHAN_X11 && c->u.x11.initial)
7669 * If the remote end has a habit of ignoring maxpkt, limit the
7670 * window so that it has no choice (assuming it doesn't ignore the
7673 if ((ssh->remote_bugs & BUG_SSH2_MAXPKT) && newwin > OUR_V2_MAXPKT)
7674 newwin = OUR_V2_MAXPKT;
7677 * Only send a WINDOW_ADJUST if there's significantly more window
7678 * available than the other end thinks there is. This saves us
7679 * sending a WINDOW_ADJUST for every character in a shell session.
7681 * "Significant" is arbitrarily defined as half the window size.
7683 if (newwin / 2 >= c->v.v2.locwindow) {
7684 struct Packet *pktout;
7688 * In order to keep track of how much window the client
7689 * actually has available, we'd like it to acknowledge each
7690 * WINDOW_ADJUST. We can't do that directly, so we accompany
7691 * it with a CHANNEL_REQUEST that has to be acknowledged.
7693 * This is only necessary if we're opening the window wide.
7694 * If we're not, then throughput is being constrained by
7695 * something other than the maximum window size anyway.
7697 if (newwin == c->v.v2.locmaxwin &&
7698 !(ssh->remote_bugs & BUG_CHOKES_ON_WINADJ)) {
7699 up = snew(unsigned);
7700 *up = newwin - c->v.v2.locwindow;
7701 pktout = ssh2_chanreq_init(c, "winadj@putty.projects.tartarus.org",
7702 ssh2_handle_winadj_response, up);
7703 ssh2_pkt_send(ssh, pktout);
7705 if (c->v.v2.throttle_state != UNTHROTTLED)
7706 c->v.v2.throttle_state = UNTHROTTLING;
7708 /* Pretend the WINDOW_ADJUST was acked immediately. */
7709 c->v.v2.remlocwin = newwin;
7710 c->v.v2.throttle_state = THROTTLED;
7712 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
7713 ssh2_pkt_adduint32(pktout, c->remoteid);
7714 ssh2_pkt_adduint32(pktout, newwin - c->v.v2.locwindow);
7715 ssh2_pkt_send(ssh, pktout);
7716 c->v.v2.locwindow = newwin;
7721 * Find the channel associated with a message. If there's no channel,
7722 * or it's not properly open, make a noise about it and return NULL.
7724 static struct ssh_channel *ssh2_channel_msg(Ssh ssh, struct Packet *pktin)
7726 unsigned localid = ssh_pkt_getuint32(pktin);
7727 struct ssh_channel *c;
7729 c = find234(ssh->channels, &localid, ssh_channelfind);
7731 (c->type != CHAN_SHARING && c->halfopen &&
7732 pktin->type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION &&
7733 pktin->type != SSH2_MSG_CHANNEL_OPEN_FAILURE)) {
7734 char *buf = dupprintf("Received %s for %s channel %u",
7735 ssh2_pkt_type(ssh->pkt_kctx, ssh->pkt_actx,
7737 c ? "half-open" : "nonexistent", localid);
7738 ssh_disconnect(ssh, NULL, buf, SSH2_DISCONNECT_PROTOCOL_ERROR, FALSE);
7745 static void ssh2_handle_winadj_response(struct ssh_channel *c,
7746 struct Packet *pktin, void *ctx)
7748 unsigned *sizep = ctx;
7751 * Winadj responses should always be failures. However, at least
7752 * one server ("boks_sshd") is known to return SUCCESS for channel
7753 * requests it's never heard of, such as "winadj@putty". Raised
7754 * with foxt.com as bug 090916-090424, but for the sake of a quiet
7755 * life, we don't worry about what kind of response we got.
7758 c->v.v2.remlocwin += *sizep;
7761 * winadj messages are only sent when the window is fully open, so
7762 * if we get an ack of one, we know any pending unthrottle is
7765 if (c->v.v2.throttle_state == UNTHROTTLING)
7766 c->v.v2.throttle_state = UNTHROTTLED;
7769 static void ssh2_msg_channel_response(Ssh ssh, struct Packet *pktin)
7771 struct ssh_channel *c = ssh2_channel_msg(ssh, pktin);
7772 struct outstanding_channel_request *ocr;
7775 if (c->type == CHAN_SHARING) {
7776 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
7777 pktin->body, pktin->length);
7780 ocr = c->v.v2.chanreq_head;
7782 ssh2_msg_unexpected(ssh, pktin);
7785 ocr->handler(c, pktin, ocr->ctx);
7786 c->v.v2.chanreq_head = ocr->next;
7789 * We may now initiate channel-closing procedures, if that
7790 * CHANNEL_REQUEST was the last thing outstanding before we send
7793 ssh2_channel_check_close(c);
7796 static void ssh2_msg_channel_window_adjust(Ssh ssh, struct Packet *pktin)
7798 struct ssh_channel *c;
7799 c = ssh2_channel_msg(ssh, pktin);
7802 if (c->type == CHAN_SHARING) {
7803 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
7804 pktin->body, pktin->length);
7807 if (!(c->closes & CLOSES_SENT_EOF)) {
7808 c->v.v2.remwindow += ssh_pkt_getuint32(pktin);
7809 ssh2_try_send_and_unthrottle(ssh, c);
7813 static void ssh2_msg_channel_data(Ssh ssh, struct Packet *pktin)
7817 struct ssh_channel *c;
7818 c = ssh2_channel_msg(ssh, pktin);
7821 if (c->type == CHAN_SHARING) {
7822 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
7823 pktin->body, pktin->length);
7826 if (pktin->type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
7827 ssh_pkt_getuint32(pktin) != SSH2_EXTENDED_DATA_STDERR)
7828 return; /* extended but not stderr */
7829 ssh_pkt_getstring(pktin, &data, &length);
7832 c->v.v2.locwindow -= length;
7833 c->v.v2.remlocwin -= length;
7835 case CHAN_MAINSESSION:
7837 from_backend(ssh->frontend, pktin->type ==
7838 SSH2_MSG_CHANNEL_EXTENDED_DATA,
7842 bufsize = x11_send(c->u.x11.xconn, data, length);
7845 bufsize = pfd_send(c->u.pfd.pf, data, length);
7848 while (length > 0) {
7849 if (c->u.a.lensofar < 4) {
7850 unsigned int l = min(4 - c->u.a.lensofar,
7852 memcpy(c->u.a.msglen + c->u.a.lensofar,
7856 c->u.a.lensofar += l;
7858 if (c->u.a.lensofar == 4) {
7860 4 + GET_32BIT(c->u.a.msglen);
7861 c->u.a.message = snewn(c->u.a.totallen,
7863 memcpy(c->u.a.message, c->u.a.msglen, 4);
7865 if (c->u.a.lensofar >= 4 && length > 0) {
7867 min(c->u.a.totallen - c->u.a.lensofar,
7869 memcpy(c->u.a.message + c->u.a.lensofar,
7873 c->u.a.lensofar += l;
7875 if (c->u.a.lensofar == c->u.a.totallen) {
7878 c->u.a.outstanding_requests++;
7879 if (agent_query(c->u.a.message,
7882 ssh_agentf_callback, c))
7883 ssh_agentf_callback(c, reply, replylen);
7884 sfree(c->u.a.message);
7885 c->u.a.message = NULL;
7886 c->u.a.lensofar = 0;
7893 * If it looks like the remote end hit the end of its window,
7894 * and we didn't want it to do that, think about using a
7897 if (c->v.v2.remlocwin <= 0 && c->v.v2.throttle_state == UNTHROTTLED &&
7898 c->v.v2.locmaxwin < 0x40000000)
7899 c->v.v2.locmaxwin += OUR_V2_WINSIZE;
7901 * If we are not buffering too much data,
7902 * enlarge the window again at the remote side.
7903 * If we are buffering too much, we may still
7904 * need to adjust the window if the server's
7907 ssh2_set_window(c, bufsize < c->v.v2.locmaxwin ?
7908 c->v.v2.locmaxwin - bufsize : 0);
7910 * If we're either buffering way too much data, or if we're
7911 * buffering anything at all and we're in "simple" mode,
7912 * throttle the whole channel.
7914 if ((bufsize > c->v.v2.locmaxwin || (ssh_is_simple(ssh) && bufsize>0))
7915 && !c->throttling_conn) {
7916 c->throttling_conn = 1;
7917 ssh_throttle_conn(ssh, +1);
7922 static void ssh_check_termination(Ssh ssh)
7924 if (ssh->version == 2 &&
7925 !conf_get_int(ssh->conf, CONF_ssh_no_shell) &&
7926 (ssh->channels && count234(ssh->channels) == 0) &&
7927 !(ssh->connshare && share_ndownstreams(ssh->connshare) > 0)) {
7929 * We used to send SSH_MSG_DISCONNECT here, because I'd
7930 * believed that _every_ conforming SSH-2 connection had to
7931 * end with a disconnect being sent by at least one side;
7932 * apparently I was wrong and it's perfectly OK to
7933 * unceremoniously slam the connection shut when you're done,
7934 * and indeed OpenSSH feels this is more polite than sending a
7935 * DISCONNECT. So now we don't.
7937 ssh_disconnect(ssh, "All channels closed", NULL, 0, TRUE);
7941 void ssh_sharing_downstream_connected(Ssh ssh, unsigned id,
7942 const char *peerinfo)
7945 logeventf(ssh, "Connection sharing downstream #%u connected from %s",
7948 logeventf(ssh, "Connection sharing downstream #%u connected", id);
7951 void ssh_sharing_downstream_disconnected(Ssh ssh, unsigned id)
7953 logeventf(ssh, "Connection sharing downstream #%u disconnected", id);
7954 ssh_check_termination(ssh);
7957 void ssh_sharing_logf(Ssh ssh, unsigned id, const char *logfmt, ...)
7962 va_start(ap, logfmt);
7963 buf = dupvprintf(logfmt, ap);
7966 logeventf(ssh, "Connection sharing downstream #%u: %s", id, buf);
7968 logeventf(ssh, "Connection sharing: %s", buf);
7972 static void ssh_channel_destroy(struct ssh_channel *c)
7977 case CHAN_MAINSESSION:
7978 ssh->mainchan = NULL;
7979 update_specials_menu(ssh->frontend);
7982 if (c->u.x11.xconn != NULL)
7983 x11_close(c->u.x11.xconn);
7984 logevent("Forwarded X11 connection terminated");
7987 sfree(c->u.a.message);
7990 if (c->u.pfd.pf != NULL)
7991 pfd_close(c->u.pfd.pf);
7992 logevent("Forwarded port closed");
7996 del234(ssh->channels, c);
7997 if (ssh->version == 2) {
7998 bufchain_clear(&c->v.v2.outbuffer);
7999 assert(c->v.v2.chanreq_head == NULL);
8004 * If that was the last channel left open, we might need to
8007 ssh_check_termination(ssh);
8010 static void ssh2_channel_check_close(struct ssh_channel *c)
8013 struct Packet *pktout;
8017 * If we've sent out our own CHANNEL_OPEN but not yet seen
8018 * either OPEN_CONFIRMATION or OPEN_FAILURE in response, then
8019 * it's too early to be sending close messages of any kind.
8024 if ((!((CLOSES_SENT_EOF | CLOSES_RCVD_EOF) & ~c->closes) ||
8025 c->type == CHAN_ZOMBIE) &&
8026 !c->v.v2.chanreq_head &&
8027 !(c->closes & CLOSES_SENT_CLOSE)) {
8029 * We have both sent and received EOF (or the channel is a
8030 * zombie), and we have no outstanding channel requests, which
8031 * means the channel is in final wind-up. But we haven't sent
8032 * CLOSE, so let's do so now.
8034 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE);
8035 ssh2_pkt_adduint32(pktout, c->remoteid);
8036 ssh2_pkt_send(ssh, pktout);
8037 c->closes |= CLOSES_SENT_EOF | CLOSES_SENT_CLOSE;
8040 if (!((CLOSES_SENT_CLOSE | CLOSES_RCVD_CLOSE) & ~c->closes)) {
8041 assert(c->v.v2.chanreq_head == NULL);
8043 * We have both sent and received CLOSE, which means we're
8044 * completely done with the channel.
8046 ssh_channel_destroy(c);
8050 static void ssh2_channel_got_eof(struct ssh_channel *c)
8052 if (c->closes & CLOSES_RCVD_EOF)
8053 return; /* already seen EOF */
8054 c->closes |= CLOSES_RCVD_EOF;
8056 if (c->type == CHAN_X11) {
8057 x11_send_eof(c->u.x11.xconn);
8058 } else if (c->type == CHAN_AGENT) {
8059 if (c->u.a.outstanding_requests == 0) {
8060 /* Manufacture an outgoing EOF in response to the incoming one. */
8061 sshfwd_write_eof(c);
8063 } else if (c->type == CHAN_SOCKDATA) {
8064 pfd_send_eof(c->u.pfd.pf);
8065 } else if (c->type == CHAN_MAINSESSION) {
8068 if (!ssh->sent_console_eof &&
8069 (from_backend_eof(ssh->frontend) || ssh->got_pty)) {
8071 * Either from_backend_eof told us that the front end
8072 * wants us to close the outgoing side of the connection
8073 * as soon as we see EOF from the far end, or else we've
8074 * unilaterally decided to do that because we've allocated
8075 * a remote pty and hence EOF isn't a particularly
8076 * meaningful concept.
8078 sshfwd_write_eof(c);
8080 ssh->sent_console_eof = TRUE;
8083 ssh2_channel_check_close(c);
8086 static void ssh2_msg_channel_eof(Ssh ssh, struct Packet *pktin)
8088 struct ssh_channel *c;
8090 c = ssh2_channel_msg(ssh, pktin);
8093 if (c->type == CHAN_SHARING) {
8094 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
8095 pktin->body, pktin->length);
8098 ssh2_channel_got_eof(c);
8101 static void ssh2_msg_channel_close(Ssh ssh, struct Packet *pktin)
8103 struct ssh_channel *c;
8105 c = ssh2_channel_msg(ssh, pktin);
8108 if (c->type == CHAN_SHARING) {
8109 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
8110 pktin->body, pktin->length);
8115 * When we receive CLOSE on a channel, we assume it comes with an
8116 * implied EOF if we haven't seen EOF yet.
8118 ssh2_channel_got_eof(c);
8120 if (!(ssh->remote_bugs & BUG_SENDS_LATE_REQUEST_REPLY)) {
8122 * It also means we stop expecting to see replies to any
8123 * outstanding channel requests, so clean those up too.
8124 * (ssh_chanreq_init will enforce by assertion that we don't
8125 * subsequently put anything back on this list.)
8127 while (c->v.v2.chanreq_head) {
8128 struct outstanding_channel_request *ocr = c->v.v2.chanreq_head;
8129 ocr->handler(c, NULL, ocr->ctx);
8130 c->v.v2.chanreq_head = ocr->next;
8136 * And we also send an outgoing EOF, if we haven't already, on the
8137 * assumption that CLOSE is a pretty forceful announcement that
8138 * the remote side is doing away with the entire channel. (If it
8139 * had wanted to send us EOF and continue receiving data from us,
8140 * it would have just sent CHANNEL_EOF.)
8142 if (!(c->closes & CLOSES_SENT_EOF)) {
8144 * Make sure we don't read any more from whatever our local
8145 * data source is for this channel.
8148 case CHAN_MAINSESSION:
8149 ssh->send_ok = 0; /* stop trying to read from stdin */
8152 x11_override_throttle(c->u.x11.xconn, 1);
8155 pfd_override_throttle(c->u.pfd.pf, 1);
8160 * Abandon any buffered data we still wanted to send to this
8161 * channel. Receiving a CHANNEL_CLOSE is an indication that
8162 * the server really wants to get on and _destroy_ this
8163 * channel, and it isn't going to send us any further
8164 * WINDOW_ADJUSTs to permit us to send pending stuff.
8166 bufchain_clear(&c->v.v2.outbuffer);
8169 * Send outgoing EOF.
8171 sshfwd_write_eof(c);
8175 * Now process the actual close.
8177 if (!(c->closes & CLOSES_RCVD_CLOSE)) {
8178 c->closes |= CLOSES_RCVD_CLOSE;
8179 ssh2_channel_check_close(c);
8183 static void ssh2_msg_channel_open_confirmation(Ssh ssh, struct Packet *pktin)
8185 struct ssh_channel *c;
8187 c = ssh2_channel_msg(ssh, pktin);
8190 if (c->type == CHAN_SHARING) {
8191 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
8192 pktin->body, pktin->length);
8195 assert(c->halfopen); /* ssh2_channel_msg will have enforced this */
8196 c->remoteid = ssh_pkt_getuint32(pktin);
8197 c->halfopen = FALSE;
8198 c->v.v2.remwindow = ssh_pkt_getuint32(pktin);
8199 c->v.v2.remmaxpkt = ssh_pkt_getuint32(pktin);
8201 if (c->type == CHAN_SOCKDATA_DORMANT) {
8202 c->type = CHAN_SOCKDATA;
8204 pfd_confirm(c->u.pfd.pf);
8205 } else if (c->type == CHAN_ZOMBIE) {
8207 * This case can occur if a local socket error occurred
8208 * between us sending out CHANNEL_OPEN and receiving
8209 * OPEN_CONFIRMATION. In this case, all we can do is
8210 * immediately initiate close proceedings now that we know the
8211 * server's id to put in the close message.
8213 ssh2_channel_check_close(c);
8216 * We never expect to receive OPEN_CONFIRMATION for any
8217 * *other* channel type (since only local-to-remote port
8218 * forwardings cause us to send CHANNEL_OPEN after the main
8219 * channel is live - all other auxiliary channel types are
8220 * initiated from the server end). It's safe to enforce this
8221 * by assertion rather than by ssh_disconnect, because the
8222 * real point is that we never constructed a half-open channel
8223 * structure in the first place with any type other than the
8226 assert(!"Funny channel type in ssh2_msg_channel_open_confirmation");
8230 ssh_channel_try_eof(c); /* in case we had a pending EOF */
8233 static void ssh2_msg_channel_open_failure(Ssh ssh, struct Packet *pktin)
8235 static const char *const reasons[] = {
8236 "<unknown reason code>",
8237 "Administratively prohibited",
8239 "Unknown channel type",
8240 "Resource shortage",
8242 unsigned reason_code;
8243 char *reason_string;
8245 struct ssh_channel *c;
8247 c = ssh2_channel_msg(ssh, pktin);
8250 if (c->type == CHAN_SHARING) {
8251 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
8252 pktin->body, pktin->length);
8255 assert(c->halfopen); /* ssh2_channel_msg will have enforced this */
8257 if (c->type == CHAN_SOCKDATA_DORMANT) {
8258 reason_code = ssh_pkt_getuint32(pktin);
8259 if (reason_code >= lenof(reasons))
8260 reason_code = 0; /* ensure reasons[reason_code] in range */
8261 ssh_pkt_getstring(pktin, &reason_string, &reason_length);
8262 logeventf(ssh, "Forwarded connection refused by server: %s [%.*s]",
8263 reasons[reason_code], reason_length, reason_string);
8265 pfd_close(c->u.pfd.pf);
8266 } else if (c->type == CHAN_ZOMBIE) {
8268 * This case can occur if a local socket error occurred
8269 * between us sending out CHANNEL_OPEN and receiving
8270 * OPEN_FAILURE. In this case, we need do nothing except allow
8271 * the code below to throw the half-open channel away.
8275 * We never expect to receive OPEN_FAILURE for any *other*
8276 * channel type (since only local-to-remote port forwardings
8277 * cause us to send CHANNEL_OPEN after the main channel is
8278 * live - all other auxiliary channel types are initiated from
8279 * the server end). It's safe to enforce this by assertion
8280 * rather than by ssh_disconnect, because the real point is
8281 * that we never constructed a half-open channel structure in
8282 * the first place with any type other than the above.
8284 assert(!"Funny channel type in ssh2_msg_channel_open_failure");
8287 del234(ssh->channels, c);
8291 static void ssh2_msg_channel_request(Ssh ssh, struct Packet *pktin)
8294 int typelen, want_reply;
8295 int reply = SSH2_MSG_CHANNEL_FAILURE; /* default */
8296 struct ssh_channel *c;
8297 struct Packet *pktout;
8299 c = ssh2_channel_msg(ssh, pktin);
8302 if (c->type == CHAN_SHARING) {
8303 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
8304 pktin->body, pktin->length);
8307 ssh_pkt_getstring(pktin, &type, &typelen);
8308 want_reply = ssh2_pkt_getbool(pktin);
8310 if (c->closes & CLOSES_SENT_CLOSE) {
8312 * We don't reply to channel requests after we've sent
8313 * CHANNEL_CLOSE for the channel, because our reply might
8314 * cross in the network with the other side's CHANNEL_CLOSE
8315 * and arrive after they have wound the channel up completely.
8321 * Having got the channel number, we now look at
8322 * the request type string to see if it's something
8325 if (c == ssh->mainchan) {
8327 * We recognise "exit-status" and "exit-signal" on
8328 * the primary channel.
8330 if (typelen == 11 &&
8331 !memcmp(type, "exit-status", 11)) {
8333 ssh->exitcode = ssh_pkt_getuint32(pktin);
8334 logeventf(ssh, "Server sent command exit status %d",
8336 reply = SSH2_MSG_CHANNEL_SUCCESS;
8338 } else if (typelen == 11 &&
8339 !memcmp(type, "exit-signal", 11)) {
8341 int is_plausible = TRUE, is_int = FALSE;
8342 char *fmt_sig = NULL, *fmt_msg = NULL;
8344 int msglen = 0, core = FALSE;
8345 /* ICK: older versions of OpenSSH (e.g. 3.4p1)
8346 * provide an `int' for the signal, despite its
8347 * having been a `string' in the drafts of RFC 4254 since at
8348 * least 2001. (Fixed in session.c 1.147.) Try to
8349 * infer which we can safely parse it as. */
8351 unsigned char *p = pktin->body +
8353 long len = pktin->length - pktin->savedpos;
8354 unsigned long num = GET_32BIT(p); /* what is it? */
8355 /* If it's 0, it hardly matters; assume string */
8359 int maybe_int = FALSE, maybe_str = FALSE;
8360 #define CHECK_HYPOTHESIS(offset, result) \
8363 int q = toint(offset); \
8364 if (q >= 0 && q+4 <= len) { \
8365 q = toint(q + 4 + GET_32BIT(p+q)); \
8366 if (q >= 0 && q+4 <= len && \
8367 ((q = toint(q + 4 + GET_32BIT(p+q))) != 0) && \
8372 CHECK_HYPOTHESIS(4+1, maybe_int);
8373 CHECK_HYPOTHESIS(4+num+1, maybe_str);
8374 #undef CHECK_HYPOTHESIS
8375 if (maybe_int && !maybe_str)
8377 else if (!maybe_int && maybe_str)
8380 /* Crikey. Either or neither. Panic. */
8381 is_plausible = FALSE;
8384 ssh->exitcode = 128; /* means `unknown signal' */
8387 /* Old non-standard OpenSSH. */
8388 int signum = ssh_pkt_getuint32(pktin);
8389 fmt_sig = dupprintf(" %d", signum);
8390 ssh->exitcode = 128 + signum;
8392 /* As per RFC 4254. */
8395 ssh_pkt_getstring(pktin, &sig, &siglen);
8396 /* Signal name isn't supposed to be blank, but
8397 * let's cope gracefully if it is. */
8399 fmt_sig = dupprintf(" \"%.*s\"",
8404 * Really hideous method of translating the
8405 * signal description back into a locally
8406 * meaningful number.
8411 #define TRANSLATE_SIGNAL(s) \
8412 else if (siglen == lenof(#s)-1 && !memcmp(sig, #s, siglen)) \
8413 ssh->exitcode = 128 + SIG ## s
8415 TRANSLATE_SIGNAL(ABRT);
8418 TRANSLATE_SIGNAL(ALRM);
8421 TRANSLATE_SIGNAL(FPE);
8424 TRANSLATE_SIGNAL(HUP);
8427 TRANSLATE_SIGNAL(ILL);
8430 TRANSLATE_SIGNAL(INT);
8433 TRANSLATE_SIGNAL(KILL);
8436 TRANSLATE_SIGNAL(PIPE);
8439 TRANSLATE_SIGNAL(QUIT);
8442 TRANSLATE_SIGNAL(SEGV);
8445 TRANSLATE_SIGNAL(TERM);
8448 TRANSLATE_SIGNAL(USR1);
8451 TRANSLATE_SIGNAL(USR2);
8453 #undef TRANSLATE_SIGNAL
8455 ssh->exitcode = 128;
8457 core = ssh2_pkt_getbool(pktin);
8458 ssh_pkt_getstring(pktin, &msg, &msglen);
8460 fmt_msg = dupprintf(" (\"%.*s\")", msglen, msg);
8462 /* ignore lang tag */
8463 } /* else don't attempt to parse */
8464 logeventf(ssh, "Server exited on signal%s%s%s",
8465 fmt_sig ? fmt_sig : "",
8466 core ? " (core dumped)" : "",
8467 fmt_msg ? fmt_msg : "");
8470 reply = SSH2_MSG_CHANNEL_SUCCESS;
8475 * This is a channel request we don't know
8476 * about, so we now either ignore the request
8477 * or respond with CHANNEL_FAILURE, depending
8480 reply = SSH2_MSG_CHANNEL_FAILURE;
8483 pktout = ssh2_pkt_init(reply);
8484 ssh2_pkt_adduint32(pktout, c->remoteid);
8485 ssh2_pkt_send(ssh, pktout);
8489 static void ssh2_msg_global_request(Ssh ssh, struct Packet *pktin)
8492 int typelen, want_reply;
8493 struct Packet *pktout;
8495 ssh_pkt_getstring(pktin, &type, &typelen);
8496 want_reply = ssh2_pkt_getbool(pktin);
8499 * We currently don't support any global requests
8500 * at all, so we either ignore the request or
8501 * respond with REQUEST_FAILURE, depending on
8505 pktout = ssh2_pkt_init(SSH2_MSG_REQUEST_FAILURE);
8506 ssh2_pkt_send(ssh, pktout);
8510 struct X11FakeAuth *ssh_sharing_add_x11_display(Ssh ssh, int authtype,
8514 struct X11FakeAuth *auth;
8517 * Make up a new set of fake X11 auth data, and add it to the tree
8518 * of currently valid ones with an indication of the sharing
8519 * context that it's relevant to.
8521 auth = x11_invent_fake_auth(ssh->x11authtree, authtype);
8522 auth->share_cs = share_cs;
8523 auth->share_chan = share_chan;
8528 void ssh_sharing_remove_x11_display(Ssh ssh, struct X11FakeAuth *auth)
8530 del234(ssh->x11authtree, auth);
8531 x11_free_fake_auth(auth);
8534 static void ssh2_msg_channel_open(Ssh ssh, struct Packet *pktin)
8541 const char *error = NULL;
8542 struct ssh_channel *c;
8543 unsigned remid, winsize, pktsize;
8544 unsigned our_winsize_override = 0;
8545 struct Packet *pktout;
8547 ssh_pkt_getstring(pktin, &type, &typelen);
8548 c = snew(struct ssh_channel);
8551 remid = ssh_pkt_getuint32(pktin);
8552 winsize = ssh_pkt_getuint32(pktin);
8553 pktsize = ssh_pkt_getuint32(pktin);
8555 if (typelen == 3 && !memcmp(type, "x11", 3)) {
8558 ssh_pkt_getstring(pktin, &peeraddr, &peeraddrlen);
8559 addrstr = snewn(peeraddrlen+1, char);
8560 memcpy(addrstr, peeraddr, peeraddrlen);
8561 addrstr[peeraddrlen] = '\0';
8562 peerport = ssh_pkt_getuint32(pktin);
8564 logeventf(ssh, "Received X11 connect request from %s:%d",
8567 if (!ssh->X11_fwd_enabled && !ssh->connshare)
8568 error = "X11 forwarding is not enabled";
8570 c->u.x11.xconn = x11_init(ssh->x11authtree, c,
8573 c->u.x11.initial = TRUE;
8576 * If we are a connection-sharing upstream, then we should
8577 * initially present a very small window, adequate to take
8578 * the X11 initial authorisation packet but not much more.
8579 * Downstream will then present us a larger window (by
8580 * fiat of the connection-sharing protocol) and we can
8581 * guarantee to send a positive-valued WINDOW_ADJUST.
8584 our_winsize_override = 128;
8586 logevent("Opened X11 forward channel");
8590 } else if (typelen == 15 &&
8591 !memcmp(type, "forwarded-tcpip", 15)) {
8592 struct ssh_rportfwd pf, *realpf;
8595 ssh_pkt_getstring(pktin, &shost, &shostlen);/* skip address */
8596 pf.shost = dupprintf("%.*s", shostlen, shost);
8597 pf.sport = ssh_pkt_getuint32(pktin);
8598 ssh_pkt_getstring(pktin, &peeraddr, &peeraddrlen);
8599 peerport = ssh_pkt_getuint32(pktin);
8600 realpf = find234(ssh->rportfwds, &pf, NULL);
8601 logeventf(ssh, "Received remote port %s:%d open request "
8602 "from %s:%d", pf.shost, pf.sport, peeraddr, peerport);
8605 if (realpf == NULL) {
8606 error = "Remote port is not recognised";
8610 if (realpf->share_ctx) {
8612 * This port forwarding is on behalf of a
8613 * connection-sharing downstream, so abandon our own
8614 * channel-open procedure and just pass the message on
8617 share_got_pkt_from_server(realpf->share_ctx, pktin->type,
8618 pktin->body, pktin->length);
8623 err = pfd_connect(&c->u.pfd.pf, realpf->dhost, realpf->dport,
8624 c, ssh->conf, realpf->pfrec->addressfamily);
8625 logeventf(ssh, "Attempting to forward remote port to "
8626 "%s:%d", realpf->dhost, realpf->dport);
8628 logeventf(ssh, "Port open failed: %s", err);
8630 error = "Port open failed";
8632 logevent("Forwarded port opened successfully");
8633 c->type = CHAN_SOCKDATA;
8636 } else if (typelen == 22 &&
8637 !memcmp(type, "auth-agent@openssh.com", 22)) {
8638 if (!ssh->agentfwd_enabled)
8639 error = "Agent forwarding is not enabled";
8641 c->type = CHAN_AGENT; /* identify channel type */
8642 c->u.a.lensofar = 0;
8643 c->u.a.message = NULL;
8644 c->u.a.outstanding_requests = 0;
8647 error = "Unsupported channel type requested";
8650 c->remoteid = remid;
8651 c->halfopen = FALSE;
8653 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_FAILURE);
8654 ssh2_pkt_adduint32(pktout, c->remoteid);
8655 ssh2_pkt_adduint32(pktout, SSH2_OPEN_CONNECT_FAILED);
8656 ssh2_pkt_addstring(pktout, error);
8657 ssh2_pkt_addstring(pktout, "en"); /* language tag */
8658 ssh2_pkt_send(ssh, pktout);
8659 logeventf(ssh, "Rejected channel open: %s", error);
8662 ssh2_channel_init(c);
8663 c->v.v2.remwindow = winsize;
8664 c->v.v2.remmaxpkt = pktsize;
8665 if (our_winsize_override) {
8666 c->v.v2.locwindow = c->v.v2.locmaxwin = c->v.v2.remlocwin =
8667 our_winsize_override;
8669 add234(ssh->channels, c);
8670 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
8671 ssh2_pkt_adduint32(pktout, c->remoteid);
8672 ssh2_pkt_adduint32(pktout, c->localid);
8673 ssh2_pkt_adduint32(pktout, c->v.v2.locwindow);
8674 ssh2_pkt_adduint32(pktout, OUR_V2_MAXPKT); /* our max pkt size */
8675 ssh2_pkt_send(ssh, pktout);
8679 void sshfwd_x11_sharing_handover(struct ssh_channel *c,
8680 void *share_cs, void *share_chan,
8681 const char *peer_addr, int peer_port,
8682 int endian, int protomajor, int protominor,
8683 const void *initial_data, int initial_len)
8686 * This function is called when we've just discovered that an X
8687 * forwarding channel on which we'd been handling the initial auth
8688 * ourselves turns out to be destined for a connection-sharing
8689 * downstream. So we turn the channel into a CHAN_SHARING, meaning
8690 * that we completely stop tracking windows and buffering data and
8691 * just pass more or less unmodified SSH messages back and forth.
8693 c->type = CHAN_SHARING;
8694 c->u.sharing.ctx = share_cs;
8695 share_setup_x11_channel(share_cs, share_chan,
8696 c->localid, c->remoteid, c->v.v2.remwindow,
8697 c->v.v2.remmaxpkt, c->v.v2.locwindow,
8698 peer_addr, peer_port, endian,
8699 protomajor, protominor,
8700 initial_data, initial_len);
8703 void sshfwd_x11_is_local(struct ssh_channel *c)
8706 * This function is called when we've just discovered that an X
8707 * forwarding channel is _not_ destined for a connection-sharing
8708 * downstream but we're going to handle it ourselves. We stop
8709 * presenting a cautiously small window and go into ordinary data
8712 c->u.x11.initial = FALSE;
8713 ssh2_set_window(c, ssh_is_simple(c->ssh) ? OUR_V2_BIGWIN : OUR_V2_WINSIZE);
8717 * Buffer banner messages for later display at some convenient point,
8718 * if we're going to display them.
8720 static void ssh2_msg_userauth_banner(Ssh ssh, struct Packet *pktin)
8722 /* Arbitrary limit to prevent unbounded inflation of buffer */
8723 if (conf_get_int(ssh->conf, CONF_ssh_show_banner) &&
8724 bufchain_size(&ssh->banner) <= 131072) {
8725 char *banner = NULL;
8727 ssh_pkt_getstring(pktin, &banner, &size);
8729 bufchain_add(&ssh->banner, banner, size);
8733 /* Helper function to deal with sending tty modes for "pty-req" */
8734 static void ssh2_send_ttymode(void *data, char *mode, char *val)
8736 struct Packet *pktout = (struct Packet *)data;
8738 unsigned int arg = 0;
8739 while (strcmp(mode, ssh_ttymodes[i].mode) != 0) i++;
8740 if (i == lenof(ssh_ttymodes)) return;
8741 switch (ssh_ttymodes[i].type) {
8743 arg = ssh_tty_parse_specchar(val);
8746 arg = ssh_tty_parse_boolean(val);
8749 ssh2_pkt_addbyte(pktout, ssh_ttymodes[i].opcode);
8750 ssh2_pkt_adduint32(pktout, arg);
8753 static void ssh2_setup_x11(struct ssh_channel *c, struct Packet *pktin,
8756 struct ssh2_setup_x11_state {
8760 struct Packet *pktout;
8761 crStateP(ssh2_setup_x11_state, ctx);
8765 logevent("Requesting X11 forwarding");
8766 pktout = ssh2_chanreq_init(ssh->mainchan, "x11-req",
8768 ssh2_pkt_addbool(pktout, 0); /* many connections */
8769 ssh2_pkt_addstring(pktout, ssh->x11auth->protoname);
8770 ssh2_pkt_addstring(pktout, ssh->x11auth->datastring);
8771 ssh2_pkt_adduint32(pktout, ssh->x11disp->screennum);
8772 ssh2_pkt_send(ssh, pktout);
8774 /* Wait to be called back with either a response packet, or NULL
8775 * meaning clean up and free our data */
8779 if (pktin->type == SSH2_MSG_CHANNEL_SUCCESS) {
8780 logevent("X11 forwarding enabled");
8781 ssh->X11_fwd_enabled = TRUE;
8783 logevent("X11 forwarding refused");
8789 static void ssh2_setup_agent(struct ssh_channel *c, struct Packet *pktin,
8792 struct ssh2_setup_agent_state {
8796 struct Packet *pktout;
8797 crStateP(ssh2_setup_agent_state, ctx);
8801 logevent("Requesting OpenSSH-style agent forwarding");
8802 pktout = ssh2_chanreq_init(ssh->mainchan, "auth-agent-req@openssh.com",
8803 ssh2_setup_agent, s);
8804 ssh2_pkt_send(ssh, pktout);
8806 /* Wait to be called back with either a response packet, or NULL
8807 * meaning clean up and free our data */
8811 if (pktin->type == SSH2_MSG_CHANNEL_SUCCESS) {
8812 logevent("Agent forwarding enabled");
8813 ssh->agentfwd_enabled = TRUE;
8815 logevent("Agent forwarding refused");
8821 static void ssh2_setup_pty(struct ssh_channel *c, struct Packet *pktin,
8824 struct ssh2_setup_pty_state {
8828 struct Packet *pktout;
8829 crStateP(ssh2_setup_pty_state, ctx);
8833 /* Unpick the terminal-speed string. */
8834 /* XXX perhaps we should allow no speeds to be sent. */
8835 ssh->ospeed = 38400; ssh->ispeed = 38400; /* last-resort defaults */
8836 sscanf(conf_get_str(ssh->conf, CONF_termspeed), "%d,%d", &ssh->ospeed, &ssh->ispeed);
8837 /* Build the pty request. */
8838 pktout = ssh2_chanreq_init(ssh->mainchan, "pty-req",
8840 ssh2_pkt_addstring(pktout, conf_get_str(ssh->conf, CONF_termtype));
8841 ssh2_pkt_adduint32(pktout, ssh->term_width);
8842 ssh2_pkt_adduint32(pktout, ssh->term_height);
8843 ssh2_pkt_adduint32(pktout, 0); /* pixel width */
8844 ssh2_pkt_adduint32(pktout, 0); /* pixel height */
8845 ssh2_pkt_addstring_start(pktout);
8846 parse_ttymodes(ssh, ssh2_send_ttymode, (void *)pktout);
8847 ssh2_pkt_addbyte(pktout, SSH2_TTY_OP_ISPEED);
8848 ssh2_pkt_adduint32(pktout, ssh->ispeed);
8849 ssh2_pkt_addbyte(pktout, SSH2_TTY_OP_OSPEED);
8850 ssh2_pkt_adduint32(pktout, ssh->ospeed);
8851 ssh2_pkt_addstring_data(pktout, "\0", 1); /* TTY_OP_END */
8852 ssh2_pkt_send(ssh, pktout);
8853 ssh->state = SSH_STATE_INTERMED;
8855 /* Wait to be called back with either a response packet, or NULL
8856 * meaning clean up and free our data */
8860 if (pktin->type == SSH2_MSG_CHANNEL_SUCCESS) {
8861 logeventf(ssh, "Allocated pty (ospeed %dbps, ispeed %dbps)",
8862 ssh->ospeed, ssh->ispeed);
8863 ssh->got_pty = TRUE;
8865 c_write_str(ssh, "Server refused to allocate pty\r\n");
8866 ssh->editing = ssh->echoing = 1;
8873 static void ssh2_setup_env(struct ssh_channel *c, struct Packet *pktin,
8876 struct ssh2_setup_env_state {
8878 int num_env, env_left, env_ok;
8881 struct Packet *pktout;
8882 crStateP(ssh2_setup_env_state, ctx);
8887 * Send environment variables.
8889 * Simplest thing here is to send all the requests at once, and
8890 * then wait for a whole bunch of successes or failures.
8896 for (val = conf_get_str_strs(ssh->conf, CONF_environmt, NULL, &key);
8898 val = conf_get_str_strs(ssh->conf, CONF_environmt, key, &key)) {
8899 pktout = ssh2_chanreq_init(ssh->mainchan, "env", ssh2_setup_env, s);
8900 ssh2_pkt_addstring(pktout, key);
8901 ssh2_pkt_addstring(pktout, val);
8902 ssh2_pkt_send(ssh, pktout);
8907 logeventf(ssh, "Sent %d environment variables", s->num_env);
8912 s->env_left = s->num_env;
8914 while (s->env_left > 0) {
8915 /* Wait to be called back with either a response packet,
8916 * or NULL meaning clean up and free our data */
8918 if (!pktin) goto out;
8919 if (pktin->type == SSH2_MSG_CHANNEL_SUCCESS)
8924 if (s->env_ok == s->num_env) {
8925 logevent("All environment variables successfully set");
8926 } else if (s->env_ok == 0) {
8927 logevent("All environment variables refused");
8928 c_write_str(ssh, "Server refused to set environment variables\r\n");
8930 logeventf(ssh, "%d environment variables refused",
8931 s->num_env - s->env_ok);
8932 c_write_str(ssh, "Server refused to set all environment variables\r\n");
8940 * Handle the SSH-2 userauth and connection layers.
8942 static void ssh2_msg_authconn(Ssh ssh, struct Packet *pktin)
8944 do_ssh2_authconn(ssh, NULL, 0, pktin);
8947 static void ssh2_response_authconn(struct ssh_channel *c, struct Packet *pktin,
8951 do_ssh2_authconn(c->ssh, NULL, 0, pktin);
8954 static void do_ssh2_authconn(Ssh ssh, const unsigned char *in, int inlen,
8955 struct Packet *pktin)
8957 struct do_ssh2_authconn_state {
8961 AUTH_TYPE_PUBLICKEY,
8962 AUTH_TYPE_PUBLICKEY_OFFER_LOUD,
8963 AUTH_TYPE_PUBLICKEY_OFFER_QUIET,
8965 AUTH_TYPE_GSSAPI, /* always QUIET */
8966 AUTH_TYPE_KEYBOARD_INTERACTIVE,
8967 AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET
8969 int done_service_req;
8970 int gotit, need_pw, can_pubkey, can_passwd, can_keyb_inter;
8971 int tried_pubkey_config, done_agent;
8976 int kbd_inter_refused;
8977 int we_are_in, userauth_success;
8978 prompts_t *cur_prompt;
8983 void *publickey_blob;
8984 int publickey_bloblen;
8985 int privatekey_available, privatekey_encrypted;
8986 char *publickey_algorithm;
8987 char *publickey_comment;
8988 unsigned char agent_request[5], *agent_response, *agentp;
8989 int agent_responselen;
8990 unsigned char *pkblob_in_agent;
8992 char *pkblob, *alg, *commentp;
8993 int pklen, alglen, commentlen;
8994 int siglen, retlen, len;
8995 char *q, *agentreq, *ret;
8997 struct Packet *pktout;
9000 struct ssh_gss_library *gsslib;
9001 Ssh_gss_ctx gss_ctx;
9002 Ssh_gss_buf gss_buf;
9003 Ssh_gss_buf gss_rcvtok, gss_sndtok;
9004 Ssh_gss_name gss_srv_name;
9005 Ssh_gss_stat gss_stat;
9008 crState(do_ssh2_authconn_state);
9012 /* Register as a handler for all the messages this coroutine handles. */
9013 ssh->packet_dispatch[SSH2_MSG_SERVICE_ACCEPT] = ssh2_msg_authconn;
9014 ssh->packet_dispatch[SSH2_MSG_USERAUTH_REQUEST] = ssh2_msg_authconn;
9015 ssh->packet_dispatch[SSH2_MSG_USERAUTH_FAILURE] = ssh2_msg_authconn;
9016 ssh->packet_dispatch[SSH2_MSG_USERAUTH_SUCCESS] = ssh2_msg_authconn;
9017 ssh->packet_dispatch[SSH2_MSG_USERAUTH_BANNER] = ssh2_msg_authconn;
9018 ssh->packet_dispatch[SSH2_MSG_USERAUTH_PK_OK] = ssh2_msg_authconn;
9019 /* ssh->packet_dispatch[SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ] = ssh2_msg_authconn; duplicate case value */
9020 /* ssh->packet_dispatch[SSH2_MSG_USERAUTH_INFO_REQUEST] = ssh2_msg_authconn; duplicate case value */
9021 ssh->packet_dispatch[SSH2_MSG_USERAUTH_INFO_RESPONSE] = ssh2_msg_authconn;
9022 ssh->packet_dispatch[SSH2_MSG_GLOBAL_REQUEST] = ssh2_msg_authconn;
9023 ssh->packet_dispatch[SSH2_MSG_REQUEST_SUCCESS] = ssh2_msg_authconn;
9024 ssh->packet_dispatch[SSH2_MSG_REQUEST_FAILURE] = ssh2_msg_authconn;
9025 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN] = ssh2_msg_authconn;
9026 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_CONFIRMATION] = ssh2_msg_authconn;
9027 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_FAILURE] = ssh2_msg_authconn;
9028 ssh->packet_dispatch[SSH2_MSG_CHANNEL_WINDOW_ADJUST] = ssh2_msg_authconn;
9029 ssh->packet_dispatch[SSH2_MSG_CHANNEL_DATA] = ssh2_msg_authconn;
9030 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EXTENDED_DATA] = ssh2_msg_authconn;
9031 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EOF] = ssh2_msg_authconn;
9032 ssh->packet_dispatch[SSH2_MSG_CHANNEL_CLOSE] = ssh2_msg_authconn;
9034 s->done_service_req = FALSE;
9035 s->we_are_in = s->userauth_success = FALSE;
9036 s->agent_response = NULL;
9038 s->tried_gssapi = FALSE;
9041 if (!ssh->bare_connection) {
9042 if (!conf_get_int(ssh->conf, CONF_ssh_no_userauth)) {
9044 * Request userauth protocol, and await a response to it.
9046 s->pktout = ssh2_pkt_init(SSH2_MSG_SERVICE_REQUEST);
9047 ssh2_pkt_addstring(s->pktout, "ssh-userauth");
9048 ssh2_pkt_send(ssh, s->pktout);
9049 crWaitUntilV(pktin);
9050 if (pktin->type == SSH2_MSG_SERVICE_ACCEPT)
9051 s->done_service_req = TRUE;
9053 if (!s->done_service_req) {
9055 * Request connection protocol directly, without authentication.
9057 s->pktout = ssh2_pkt_init(SSH2_MSG_SERVICE_REQUEST);
9058 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9059 ssh2_pkt_send(ssh, s->pktout);
9060 crWaitUntilV(pktin);
9061 if (pktin->type == SSH2_MSG_SERVICE_ACCEPT) {
9062 s->we_are_in = TRUE; /* no auth required */
9064 bombout(("Server refused service request"));
9069 s->we_are_in = TRUE;
9072 /* Arrange to be able to deal with any BANNERs that come in.
9073 * (We do this now as packets may come in during the next bit.) */
9074 bufchain_init(&ssh->banner);
9075 ssh->packet_dispatch[SSH2_MSG_USERAUTH_BANNER] =
9076 ssh2_msg_userauth_banner;
9079 * Misc one-time setup for authentication.
9081 s->publickey_blob = NULL;
9082 if (!s->we_are_in) {
9085 * Load the public half of any configured public key file
9088 s->keyfile = conf_get_filename(ssh->conf, CONF_keyfile);
9089 if (!filename_is_null(s->keyfile)) {
9091 logeventf(ssh, "Reading key file \"%.150s\"",
9092 filename_to_str(s->keyfile));
9093 keytype = key_type(s->keyfile);
9094 if (keytype == SSH_KEYTYPE_SSH2 ||
9095 keytype == SSH_KEYTYPE_SSH2_PUBLIC_RFC4716 ||
9096 keytype == SSH_KEYTYPE_SSH2_PUBLIC_OPENSSH) {
9099 ssh2_userkey_loadpub(s->keyfile,
9100 &s->publickey_algorithm,
9101 &s->publickey_bloblen,
9102 &s->publickey_comment, &error);
9103 if (s->publickey_blob) {
9104 s->privatekey_available = (keytype == SSH_KEYTYPE_SSH2);
9105 if (!s->privatekey_available)
9106 logeventf(ssh, "Key file contains public key only");
9107 s->privatekey_encrypted =
9108 ssh2_userkey_encrypted(s->keyfile, NULL);
9111 logeventf(ssh, "Unable to load key (%s)",
9113 msgbuf = dupprintf("Unable to load key file "
9114 "\"%.150s\" (%s)\r\n",
9115 filename_to_str(s->keyfile),
9117 c_write_str(ssh, msgbuf);
9122 logeventf(ssh, "Unable to use this key file (%s)",
9123 key_type_to_str(keytype));
9124 msgbuf = dupprintf("Unable to use key file \"%.150s\""
9126 filename_to_str(s->keyfile),
9127 key_type_to_str(keytype));
9128 c_write_str(ssh, msgbuf);
9130 s->publickey_blob = NULL;
9135 * Find out about any keys Pageant has (but if there's a
9136 * public key configured, filter out all others).
9139 s->agent_response = NULL;
9140 s->pkblob_in_agent = NULL;
9141 if (conf_get_int(ssh->conf, CONF_tryagent) && agent_exists()) {
9145 logevent("Pageant is running. Requesting keys.");
9147 /* Request the keys held by the agent. */
9148 PUT_32BIT(s->agent_request, 1);
9149 s->agent_request[4] = SSH2_AGENTC_REQUEST_IDENTITIES;
9150 if (!agent_query(s->agent_request, 5, &r, &s->agent_responselen,
9151 ssh_agent_callback, ssh)) {
9155 bombout(("Unexpected data from server while"
9156 " waiting for agent response"));
9159 } while (pktin || inlen > 0);
9160 r = ssh->agent_response;
9161 s->agent_responselen = ssh->agent_response_len;
9163 s->agent_response = (unsigned char *) r;
9164 if (s->agent_response && s->agent_responselen >= 5 &&
9165 s->agent_response[4] == SSH2_AGENT_IDENTITIES_ANSWER) {
9168 p = s->agent_response + 5;
9169 s->nkeys = toint(GET_32BIT(p));
9172 * Vet the Pageant response to ensure that the key
9173 * count and blob lengths make sense.
9176 logeventf(ssh, "Pageant response contained a negative"
9177 " key count %d", s->nkeys);
9179 goto done_agent_query;
9181 unsigned char *q = p + 4;
9182 int lenleft = s->agent_responselen - 5 - 4;
9184 for (keyi = 0; keyi < s->nkeys; keyi++) {
9185 int bloblen, commentlen;
9187 logeventf(ssh, "Pageant response was truncated");
9189 goto done_agent_query;
9191 bloblen = toint(GET_32BIT(q));
9192 if (bloblen < 0 || bloblen > lenleft) {
9193 logeventf(ssh, "Pageant response was truncated");
9195 goto done_agent_query;
9197 lenleft -= 4 + bloblen;
9199 commentlen = toint(GET_32BIT(q));
9200 if (commentlen < 0 || commentlen > lenleft) {
9201 logeventf(ssh, "Pageant response was truncated");
9203 goto done_agent_query;
9205 lenleft -= 4 + commentlen;
9206 q += 4 + commentlen;
9211 logeventf(ssh, "Pageant has %d SSH-2 keys", s->nkeys);
9212 if (s->publickey_blob) {
9213 /* See if configured key is in agent. */
9214 for (keyi = 0; keyi < s->nkeys; keyi++) {
9215 s->pklen = toint(GET_32BIT(p));
9216 if (s->pklen == s->publickey_bloblen &&
9217 !memcmp(p+4, s->publickey_blob,
9218 s->publickey_bloblen)) {
9219 logeventf(ssh, "Pageant key #%d matches "
9220 "configured key file", keyi);
9222 s->pkblob_in_agent = p;
9226 p += toint(GET_32BIT(p)) + 4; /* comment */
9228 if (!s->pkblob_in_agent) {
9229 logevent("Configured key file not in Pageant");
9234 logevent("Failed to get reply from Pageant");
9242 * We repeat this whole loop, including the username prompt,
9243 * until we manage a successful authentication. If the user
9244 * types the wrong _password_, they can be sent back to the
9245 * beginning to try another username, if this is configured on.
9246 * (If they specify a username in the config, they are never
9247 * asked, even if they do give a wrong password.)
9249 * I think this best serves the needs of
9251 * - the people who have no configuration, no keys, and just
9252 * want to try repeated (username,password) pairs until they
9253 * type both correctly
9255 * - people who have keys and configuration but occasionally
9256 * need to fall back to passwords
9258 * - people with a key held in Pageant, who might not have
9259 * logged in to a particular machine before; so they want to
9260 * type a username, and then _either_ their key will be
9261 * accepted, _or_ they will type a password. If they mistype
9262 * the username they will want to be able to get back and
9265 s->got_username = FALSE;
9266 while (!s->we_are_in) {
9270 if (s->got_username && !conf_get_int(ssh->conf, CONF_change_username)) {
9272 * We got a username last time round this loop, and
9273 * with change_username turned off we don't try to get
9276 } else if ((ssh->username = get_remote_username(ssh->conf)) == NULL) {
9277 int ret; /* need not be kept over crReturn */
9278 s->cur_prompt = new_prompts(ssh->frontend);
9279 s->cur_prompt->to_server = TRUE;
9280 s->cur_prompt->name = dupstr("SSH login name");
9281 add_prompt(s->cur_prompt, dupstr("login as: "), TRUE);
9282 ret = get_userpass_input(s->cur_prompt, NULL, 0);
9285 crWaitUntilV(!pktin);
9286 ret = get_userpass_input(s->cur_prompt, in, inlen);
9291 * get_userpass_input() failed to get a username.
9294 free_prompts(s->cur_prompt);
9295 ssh_disconnect(ssh, "No username provided", NULL, 0, TRUE);
9298 ssh->username = dupstr(s->cur_prompt->prompts[0]->result);
9299 free_prompts(s->cur_prompt);
9302 if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
9303 stuff = dupprintf("Using username \"%s\".\r\n", ssh->username);
9304 c_write_str(ssh, stuff);
9308 s->got_username = TRUE;
9311 * Send an authentication request using method "none": (a)
9312 * just in case it succeeds, and (b) so that we know what
9313 * authentication methods we can usefully try next.
9315 ssh->pkt_actx = SSH2_PKTCTX_NOAUTH;
9317 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9318 ssh2_pkt_addstring(s->pktout, ssh->username);
9319 ssh2_pkt_addstring(s->pktout, "ssh-connection");/* service requested */
9320 ssh2_pkt_addstring(s->pktout, "none"); /* method */
9321 ssh2_pkt_send(ssh, s->pktout);
9322 s->type = AUTH_TYPE_NONE;
9324 s->we_are_in = FALSE;
9326 s->tried_pubkey_config = FALSE;
9327 s->kbd_inter_refused = FALSE;
9329 /* Reset agent request state. */
9330 s->done_agent = FALSE;
9331 if (s->agent_response) {
9332 if (s->pkblob_in_agent) {
9333 s->agentp = s->pkblob_in_agent;
9335 s->agentp = s->agent_response + 5 + 4;
9341 char *methods = NULL;
9345 * Wait for the result of the last authentication request.
9348 crWaitUntilV(pktin);
9350 * Now is a convenient point to spew any banner material
9351 * that we've accumulated. (This should ensure that when
9352 * we exit the auth loop, we haven't any left to deal
9356 int size = bufchain_size(&ssh->banner);
9358 * Don't show the banner if we're operating in
9359 * non-verbose non-interactive mode. (It's probably
9360 * a script, which means nobody will read the
9361 * banner _anyway_, and moreover the printing of
9362 * the banner will screw up processing on the
9363 * output of (say) plink.)
9365 if (size && (flags & (FLAG_VERBOSE | FLAG_INTERACTIVE))) {
9366 char *banner = snewn(size, char);
9367 bufchain_fetch(&ssh->banner, banner, size);
9368 c_write_untrusted(ssh, banner, size);
9371 bufchain_clear(&ssh->banner);
9373 if (pktin->type == SSH2_MSG_USERAUTH_SUCCESS) {
9374 logevent("Access granted");
9375 s->we_are_in = s->userauth_success = TRUE;
9379 if (pktin->type != SSH2_MSG_USERAUTH_FAILURE && s->type != AUTH_TYPE_GSSAPI) {
9380 bombout(("Strange packet received during authentication: "
9381 "type %d", pktin->type));
9388 * OK, we're now sitting on a USERAUTH_FAILURE message, so
9389 * we can look at the string in it and know what we can
9390 * helpfully try next.
9392 if (pktin->type == SSH2_MSG_USERAUTH_FAILURE) {
9393 ssh_pkt_getstring(pktin, &methods, &methlen);
9394 if (!ssh2_pkt_getbool(pktin)) {
9396 * We have received an unequivocal Access
9397 * Denied. This can translate to a variety of
9398 * messages, or no message at all.
9400 * For forms of authentication which are attempted
9401 * implicitly, by which I mean without printing
9402 * anything in the window indicating that we're
9403 * trying them, we should never print 'Access
9406 * If we do print a message saying that we're
9407 * attempting some kind of authentication, it's OK
9408 * to print a followup message saying it failed -
9409 * but the message may sometimes be more specific
9410 * than simply 'Access denied'.
9412 * Additionally, if we'd just tried password
9413 * authentication, we should break out of this
9414 * whole loop so as to go back to the username
9415 * prompt (iff we're configured to allow
9416 * username change attempts).
9418 if (s->type == AUTH_TYPE_NONE) {
9420 } else if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD ||
9421 s->type == AUTH_TYPE_PUBLICKEY_OFFER_QUIET) {
9422 if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD)
9423 c_write_str(ssh, "Server refused our key\r\n");
9424 logevent("Server refused our key");
9425 } else if (s->type == AUTH_TYPE_PUBLICKEY) {
9426 /* This _shouldn't_ happen except by a
9427 * protocol bug causing client and server to
9428 * disagree on what is a correct signature. */
9429 c_write_str(ssh, "Server refused public-key signature"
9430 " despite accepting key!\r\n");
9431 logevent("Server refused public-key signature"
9432 " despite accepting key!");
9433 } else if (s->type==AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET) {
9434 /* quiet, so no c_write */
9435 logevent("Server refused keyboard-interactive authentication");
9436 } else if (s->type==AUTH_TYPE_GSSAPI) {
9437 /* always quiet, so no c_write */
9438 /* also, the code down in the GSSAPI block has
9439 * already logged this in the Event Log */
9440 } else if (s->type == AUTH_TYPE_KEYBOARD_INTERACTIVE) {
9441 logevent("Keyboard-interactive authentication failed");
9442 c_write_str(ssh, "Access denied\r\n");
9444 assert(s->type == AUTH_TYPE_PASSWORD);
9445 logevent("Password authentication failed");
9446 c_write_str(ssh, "Access denied\r\n");
9448 if (conf_get_int(ssh->conf, CONF_change_username)) {
9449 /* XXX perhaps we should allow
9450 * keyboard-interactive to do this too? */
9451 s->we_are_in = FALSE;
9456 c_write_str(ssh, "Further authentication required\r\n");
9457 logevent("Further authentication required");
9461 in_commasep_string("publickey", methods, methlen);
9463 in_commasep_string("password", methods, methlen);
9464 s->can_keyb_inter = conf_get_int(ssh->conf, CONF_try_ki_auth) &&
9465 in_commasep_string("keyboard-interactive", methods, methlen);
9467 if (conf_get_int(ssh->conf, CONF_try_gssapi_auth) &&
9468 in_commasep_string("gssapi-with-mic", methods, methlen)) {
9469 /* Try loading the GSS libraries and see if we
9472 ssh->gsslibs = ssh_gss_setup(ssh->conf);
9473 s->can_gssapi = (ssh->gsslibs->nlibraries > 0);
9475 /* No point in even bothering to try to load the
9476 * GSS libraries, if the user configuration and
9477 * server aren't both prepared to attempt GSSAPI
9478 * auth in the first place. */
9479 s->can_gssapi = FALSE;
9484 ssh->pkt_actx = SSH2_PKTCTX_NOAUTH;
9486 if (s->can_pubkey && !s->done_agent && s->nkeys) {
9489 * Attempt public-key authentication using a key from Pageant.
9492 ssh->pkt_actx = SSH2_PKTCTX_PUBLICKEY;
9494 logeventf(ssh, "Trying Pageant key #%d", s->keyi);
9496 /* Unpack key from agent response */
9497 s->pklen = toint(GET_32BIT(s->agentp));
9499 s->pkblob = (char *)s->agentp;
9500 s->agentp += s->pklen;
9501 s->alglen = toint(GET_32BIT(s->pkblob));
9502 s->alg = s->pkblob + 4;
9503 s->commentlen = toint(GET_32BIT(s->agentp));
9505 s->commentp = (char *)s->agentp;
9506 s->agentp += s->commentlen;
9507 /* s->agentp now points at next key, if any */
9509 /* See if server will accept it */
9510 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9511 ssh2_pkt_addstring(s->pktout, ssh->username);
9512 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9513 /* service requested */
9514 ssh2_pkt_addstring(s->pktout, "publickey");
9516 ssh2_pkt_addbool(s->pktout, FALSE); /* no signature included */
9517 ssh2_pkt_addstring_start(s->pktout);
9518 ssh2_pkt_addstring_data(s->pktout, s->alg, s->alglen);
9519 ssh2_pkt_addstring_start(s->pktout);
9520 ssh2_pkt_addstring_data(s->pktout, s->pkblob, s->pklen);
9521 ssh2_pkt_send(ssh, s->pktout);
9522 s->type = AUTH_TYPE_PUBLICKEY_OFFER_QUIET;
9524 crWaitUntilV(pktin);
9525 if (pktin->type != SSH2_MSG_USERAUTH_PK_OK) {
9527 /* Offer of key refused. */
9534 if (flags & FLAG_VERBOSE) {
9535 c_write_str(ssh, "Authenticating with "
9537 c_write(ssh, s->commentp, s->commentlen);
9538 c_write_str(ssh, "\" from agent\r\n");
9542 * Server is willing to accept the key.
9543 * Construct a SIGN_REQUEST.
9545 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9546 ssh2_pkt_addstring(s->pktout, ssh->username);
9547 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9548 /* service requested */
9549 ssh2_pkt_addstring(s->pktout, "publickey");
9551 ssh2_pkt_addbool(s->pktout, TRUE); /* signature included */
9552 ssh2_pkt_addstring_start(s->pktout);
9553 ssh2_pkt_addstring_data(s->pktout, s->alg, s->alglen);
9554 ssh2_pkt_addstring_start(s->pktout);
9555 ssh2_pkt_addstring_data(s->pktout, s->pkblob, s->pklen);
9557 /* Ask agent for signature. */
9558 s->siglen = s->pktout->length - 5 + 4 +
9559 ssh->v2_session_id_len;
9560 if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
9562 s->len = 1; /* message type */
9563 s->len += 4 + s->pklen; /* key blob */
9564 s->len += 4 + s->siglen; /* data to sign */
9565 s->len += 4; /* flags */
9566 s->agentreq = snewn(4 + s->len, char);
9567 PUT_32BIT(s->agentreq, s->len);
9568 s->q = s->agentreq + 4;
9569 *s->q++ = SSH2_AGENTC_SIGN_REQUEST;
9570 PUT_32BIT(s->q, s->pklen);
9572 memcpy(s->q, s->pkblob, s->pklen);
9574 PUT_32BIT(s->q, s->siglen);
9576 /* Now the data to be signed... */
9577 if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
9578 PUT_32BIT(s->q, ssh->v2_session_id_len);
9581 memcpy(s->q, ssh->v2_session_id,
9582 ssh->v2_session_id_len);
9583 s->q += ssh->v2_session_id_len;
9584 memcpy(s->q, s->pktout->data + 5,
9585 s->pktout->length - 5);
9586 s->q += s->pktout->length - 5;
9587 /* And finally the (zero) flags word. */
9589 if (!agent_query(s->agentreq, s->len + 4,
9591 ssh_agent_callback, ssh)) {
9595 bombout(("Unexpected data from server"
9596 " while waiting for agent"
9600 } while (pktin || inlen > 0);
9601 vret = ssh->agent_response;
9602 s->retlen = ssh->agent_response_len;
9607 if (s->retlen >= 9 &&
9608 s->ret[4] == SSH2_AGENT_SIGN_RESPONSE &&
9609 GET_32BIT(s->ret + 5) <= (unsigned)(s->retlen-9)) {
9610 logevent("Sending Pageant's response");
9611 ssh2_add_sigblob(ssh, s->pktout,
9612 s->pkblob, s->pklen,
9614 GET_32BIT(s->ret + 5));
9615 ssh2_pkt_send(ssh, s->pktout);
9616 s->type = AUTH_TYPE_PUBLICKEY;
9618 /* FIXME: less drastic response */
9619 bombout(("Pageant failed to answer challenge"));
9625 /* Do we have any keys left to try? */
9626 if (s->pkblob_in_agent) {
9627 s->done_agent = TRUE;
9628 s->tried_pubkey_config = TRUE;
9631 if (s->keyi >= s->nkeys)
9632 s->done_agent = TRUE;
9635 } else if (s->can_pubkey && s->publickey_blob &&
9636 s->privatekey_available && !s->tried_pubkey_config) {
9638 struct ssh2_userkey *key; /* not live over crReturn */
9639 char *passphrase; /* not live over crReturn */
9641 ssh->pkt_actx = SSH2_PKTCTX_PUBLICKEY;
9643 s->tried_pubkey_config = TRUE;
9646 * Try the public key supplied in the configuration.
9648 * First, offer the public blob to see if the server is
9649 * willing to accept it.
9651 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9652 ssh2_pkt_addstring(s->pktout, ssh->username);
9653 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9654 /* service requested */
9655 ssh2_pkt_addstring(s->pktout, "publickey"); /* method */
9656 ssh2_pkt_addbool(s->pktout, FALSE);
9657 /* no signature included */
9658 ssh2_pkt_addstring(s->pktout, s->publickey_algorithm);
9659 ssh2_pkt_addstring_start(s->pktout);
9660 ssh2_pkt_addstring_data(s->pktout,
9661 (char *)s->publickey_blob,
9662 s->publickey_bloblen);
9663 ssh2_pkt_send(ssh, s->pktout);
9664 logevent("Offered public key");
9666 crWaitUntilV(pktin);
9667 if (pktin->type != SSH2_MSG_USERAUTH_PK_OK) {
9668 /* Key refused. Give up. */
9669 s->gotit = TRUE; /* reconsider message next loop */
9670 s->type = AUTH_TYPE_PUBLICKEY_OFFER_LOUD;
9671 continue; /* process this new message */
9673 logevent("Offer of public key accepted");
9676 * Actually attempt a serious authentication using
9679 if (flags & FLAG_VERBOSE) {
9680 c_write_str(ssh, "Authenticating with public key \"");
9681 c_write_str(ssh, s->publickey_comment);
9682 c_write_str(ssh, "\"\r\n");
9686 const char *error; /* not live over crReturn */
9687 if (s->privatekey_encrypted) {
9689 * Get a passphrase from the user.
9691 int ret; /* need not be kept over crReturn */
9692 s->cur_prompt = new_prompts(ssh->frontend);
9693 s->cur_prompt->to_server = FALSE;
9694 s->cur_prompt->name = dupstr("SSH key passphrase");
9695 add_prompt(s->cur_prompt,
9696 dupprintf("Passphrase for key \"%.100s\": ",
9697 s->publickey_comment),
9699 ret = get_userpass_input(s->cur_prompt, NULL, 0);
9702 crWaitUntilV(!pktin);
9703 ret = get_userpass_input(s->cur_prompt,
9708 /* Failed to get a passphrase. Terminate. */
9709 free_prompts(s->cur_prompt);
9710 ssh_disconnect(ssh, NULL,
9711 "Unable to authenticate",
9712 SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER,
9717 dupstr(s->cur_prompt->prompts[0]->result);
9718 free_prompts(s->cur_prompt);
9720 passphrase = NULL; /* no passphrase needed */
9724 * Try decrypting the key.
9726 s->keyfile = conf_get_filename(ssh->conf, CONF_keyfile);
9727 key = ssh2_load_userkey(s->keyfile, passphrase, &error);
9729 /* burn the evidence */
9730 smemclr(passphrase, strlen(passphrase));
9733 if (key == SSH2_WRONG_PASSPHRASE || key == NULL) {
9735 (key == SSH2_WRONG_PASSPHRASE)) {
9736 c_write_str(ssh, "Wrong passphrase\r\n");
9738 /* and loop again */
9740 c_write_str(ssh, "Unable to load private key (");
9741 c_write_str(ssh, error);
9742 c_write_str(ssh, ")\r\n");
9744 break; /* try something else */
9750 unsigned char *pkblob, *sigblob, *sigdata;
9751 int pkblob_len, sigblob_len, sigdata_len;
9755 * We have loaded the private key and the server
9756 * has announced that it's willing to accept it.
9757 * Hallelujah. Generate a signature and send it.
9759 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9760 ssh2_pkt_addstring(s->pktout, ssh->username);
9761 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9762 /* service requested */
9763 ssh2_pkt_addstring(s->pktout, "publickey");
9765 ssh2_pkt_addbool(s->pktout, TRUE);
9766 /* signature follows */
9767 ssh2_pkt_addstring(s->pktout, key->alg->name);
9768 pkblob = key->alg->public_blob(key->data,
9770 ssh2_pkt_addstring_start(s->pktout);
9771 ssh2_pkt_addstring_data(s->pktout, (char *)pkblob,
9775 * The data to be signed is:
9779 * followed by everything so far placed in the
9782 sigdata_len = s->pktout->length - 5 + 4 +
9783 ssh->v2_session_id_len;
9784 if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
9786 sigdata = snewn(sigdata_len, unsigned char);
9788 if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
9789 PUT_32BIT(sigdata+p, ssh->v2_session_id_len);
9792 memcpy(sigdata+p, ssh->v2_session_id,
9793 ssh->v2_session_id_len);
9794 p += ssh->v2_session_id_len;
9795 memcpy(sigdata+p, s->pktout->data + 5,
9796 s->pktout->length - 5);
9797 p += s->pktout->length - 5;
9798 assert(p == sigdata_len);
9799 sigblob = key->alg->sign(key->data, (char *)sigdata,
9800 sigdata_len, &sigblob_len);
9801 ssh2_add_sigblob(ssh, s->pktout, pkblob, pkblob_len,
9802 sigblob, sigblob_len);
9807 ssh2_pkt_send(ssh, s->pktout);
9808 logevent("Sent public key signature");
9809 s->type = AUTH_TYPE_PUBLICKEY;
9810 key->alg->freekey(key->data);
9811 sfree(key->comment);
9816 } else if (s->can_gssapi && !s->tried_gssapi) {
9818 /* GSSAPI Authentication */
9823 s->type = AUTH_TYPE_GSSAPI;
9824 s->tried_gssapi = TRUE;
9826 ssh->pkt_actx = SSH2_PKTCTX_GSSAPI;
9829 * Pick the highest GSS library on the preference
9835 for (i = 0; i < ngsslibs; i++) {
9836 int want_id = conf_get_int_int(ssh->conf,
9837 CONF_ssh_gsslist, i);
9838 for (j = 0; j < ssh->gsslibs->nlibraries; j++)
9839 if (ssh->gsslibs->libraries[j].id == want_id) {
9840 s->gsslib = &ssh->gsslibs->libraries[j];
9841 goto got_gsslib; /* double break */
9846 * We always expect to have found something in
9847 * the above loop: we only came here if there
9848 * was at least one viable GSS library, and the
9849 * preference list should always mention
9850 * everything and only change the order.
9855 if (s->gsslib->gsslogmsg)
9856 logevent(s->gsslib->gsslogmsg);
9858 /* Sending USERAUTH_REQUEST with "gssapi-with-mic" method */
9859 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9860 ssh2_pkt_addstring(s->pktout, ssh->username);
9861 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9862 ssh2_pkt_addstring(s->pktout, "gssapi-with-mic");
9863 logevent("Attempting GSSAPI authentication");
9865 /* add mechanism info */
9866 s->gsslib->indicate_mech(s->gsslib, &s->gss_buf);
9868 /* number of GSSAPI mechanisms */
9869 ssh2_pkt_adduint32(s->pktout,1);
9871 /* length of OID + 2 */
9872 ssh2_pkt_adduint32(s->pktout, s->gss_buf.length + 2);
9873 ssh2_pkt_addbyte(s->pktout, SSH2_GSS_OIDTYPE);
9876 ssh2_pkt_addbyte(s->pktout, (unsigned char) s->gss_buf.length);
9878 ssh_pkt_adddata(s->pktout, s->gss_buf.value,
9880 ssh2_pkt_send(ssh, s->pktout);
9881 crWaitUntilV(pktin);
9882 if (pktin->type != SSH2_MSG_USERAUTH_GSSAPI_RESPONSE) {
9883 logevent("GSSAPI authentication request refused");
9887 /* check returned packet ... */
9889 ssh_pkt_getstring(pktin, &data, &len);
9890 s->gss_rcvtok.value = data;
9891 s->gss_rcvtok.length = len;
9892 if (s->gss_rcvtok.length != s->gss_buf.length + 2 ||
9893 ((char *)s->gss_rcvtok.value)[0] != SSH2_GSS_OIDTYPE ||
9894 ((char *)s->gss_rcvtok.value)[1] != s->gss_buf.length ||
9895 memcmp((char *)s->gss_rcvtok.value + 2,
9896 s->gss_buf.value,s->gss_buf.length) ) {
9897 logevent("GSSAPI authentication - wrong response from server");
9901 /* now start running */
9902 s->gss_stat = s->gsslib->import_name(s->gsslib,
9905 if (s->gss_stat != SSH_GSS_OK) {
9906 if (s->gss_stat == SSH_GSS_BAD_HOST_NAME)
9907 logevent("GSSAPI import name failed - Bad service name");
9909 logevent("GSSAPI import name failed");
9913 /* fetch TGT into GSS engine */
9914 s->gss_stat = s->gsslib->acquire_cred(s->gsslib, &s->gss_ctx);
9916 if (s->gss_stat != SSH_GSS_OK) {
9917 logevent("GSSAPI authentication failed to get credentials");
9918 s->gsslib->release_name(s->gsslib, &s->gss_srv_name);
9922 /* initial tokens are empty */
9923 SSH_GSS_CLEAR_BUF(&s->gss_rcvtok);
9924 SSH_GSS_CLEAR_BUF(&s->gss_sndtok);
9926 /* now enter the loop */
9928 s->gss_stat = s->gsslib->init_sec_context
9932 conf_get_int(ssh->conf, CONF_gssapifwd),
9936 if (s->gss_stat!=SSH_GSS_S_COMPLETE &&
9937 s->gss_stat!=SSH_GSS_S_CONTINUE_NEEDED) {
9938 logevent("GSSAPI authentication initialisation failed");
9940 if (s->gsslib->display_status(s->gsslib, s->gss_ctx,
9941 &s->gss_buf) == SSH_GSS_OK) {
9942 logevent(s->gss_buf.value);
9943 sfree(s->gss_buf.value);
9948 logevent("GSSAPI authentication initialised");
9950 /* Client and server now exchange tokens until GSSAPI
9951 * no longer says CONTINUE_NEEDED */
9953 if (s->gss_sndtok.length != 0) {
9954 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
9955 ssh_pkt_addstring_start(s->pktout);
9956 ssh_pkt_addstring_data(s->pktout,s->gss_sndtok.value,s->gss_sndtok.length);
9957 ssh2_pkt_send(ssh, s->pktout);
9958 s->gsslib->free_tok(s->gsslib, &s->gss_sndtok);
9961 if (s->gss_stat == SSH_GSS_S_CONTINUE_NEEDED) {
9962 crWaitUntilV(pktin);
9963 if (pktin->type != SSH2_MSG_USERAUTH_GSSAPI_TOKEN) {
9964 logevent("GSSAPI authentication - bad server response");
9965 s->gss_stat = SSH_GSS_FAILURE;
9968 ssh_pkt_getstring(pktin, &data, &len);
9969 s->gss_rcvtok.value = data;
9970 s->gss_rcvtok.length = len;
9972 } while (s-> gss_stat == SSH_GSS_S_CONTINUE_NEEDED);
9974 if (s->gss_stat != SSH_GSS_OK) {
9975 s->gsslib->release_name(s->gsslib, &s->gss_srv_name);
9976 s->gsslib->release_cred(s->gsslib, &s->gss_ctx);
9979 logevent("GSSAPI authentication loop finished OK");
9981 /* Now send the MIC */
9983 s->pktout = ssh2_pkt_init(0);
9984 micoffset = s->pktout->length;
9985 ssh_pkt_addstring_start(s->pktout);
9986 ssh_pkt_addstring_data(s->pktout, (char *)ssh->v2_session_id, ssh->v2_session_id_len);
9987 ssh_pkt_addbyte(s->pktout, SSH2_MSG_USERAUTH_REQUEST);
9988 ssh_pkt_addstring(s->pktout, ssh->username);
9989 ssh_pkt_addstring(s->pktout, "ssh-connection");
9990 ssh_pkt_addstring(s->pktout, "gssapi-with-mic");
9992 s->gss_buf.value = (char *)s->pktout->data + micoffset;
9993 s->gss_buf.length = s->pktout->length - micoffset;
9995 s->gsslib->get_mic(s->gsslib, s->gss_ctx, &s->gss_buf, &mic);
9996 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_GSSAPI_MIC);
9997 ssh_pkt_addstring_start(s->pktout);
9998 ssh_pkt_addstring_data(s->pktout, mic.value, mic.length);
9999 ssh2_pkt_send(ssh, s->pktout);
10000 s->gsslib->free_mic(s->gsslib, &mic);
10004 s->gsslib->release_name(s->gsslib, &s->gss_srv_name);
10005 s->gsslib->release_cred(s->gsslib, &s->gss_ctx);
10008 } else if (s->can_keyb_inter && !s->kbd_inter_refused) {
10011 * Keyboard-interactive authentication.
10014 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
10016 ssh->pkt_actx = SSH2_PKTCTX_KBDINTER;
10018 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
10019 ssh2_pkt_addstring(s->pktout, ssh->username);
10020 ssh2_pkt_addstring(s->pktout, "ssh-connection");
10021 /* service requested */
10022 ssh2_pkt_addstring(s->pktout, "keyboard-interactive");
10024 ssh2_pkt_addstring(s->pktout, ""); /* lang */
10025 ssh2_pkt_addstring(s->pktout, ""); /* submethods */
10026 ssh2_pkt_send(ssh, s->pktout);
10028 logevent("Attempting keyboard-interactive authentication");
10030 crWaitUntilV(pktin);
10031 if (pktin->type != SSH2_MSG_USERAUTH_INFO_REQUEST) {
10032 /* Server is not willing to do keyboard-interactive
10033 * at all (or, bizarrely but legally, accepts the
10034 * user without actually issuing any prompts).
10035 * Give up on it entirely. */
10037 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET;
10038 s->kbd_inter_refused = TRUE; /* don't try it again */
10043 * Loop while the server continues to send INFO_REQUESTs.
10045 while (pktin->type == SSH2_MSG_USERAUTH_INFO_REQUEST) {
10047 char *name, *inst, *lang;
10048 int name_len, inst_len, lang_len;
10052 * We've got a fresh USERAUTH_INFO_REQUEST.
10053 * Get the preamble and start building a prompt.
10055 ssh_pkt_getstring(pktin, &name, &name_len);
10056 ssh_pkt_getstring(pktin, &inst, &inst_len);
10057 ssh_pkt_getstring(pktin, &lang, &lang_len);
10058 s->cur_prompt = new_prompts(ssh->frontend);
10059 s->cur_prompt->to_server = TRUE;
10062 * Get any prompt(s) from the packet.
10064 s->num_prompts = ssh_pkt_getuint32(pktin);
10065 for (i = 0; i < s->num_prompts; i++) {
10069 static char noprompt[] =
10070 "<server failed to send prompt>: ";
10072 ssh_pkt_getstring(pktin, &prompt, &prompt_len);
10073 echo = ssh2_pkt_getbool(pktin);
10076 prompt_len = lenof(noprompt)-1;
10078 add_prompt(s->cur_prompt,
10079 dupprintf("%.*s", prompt_len, prompt),
10084 /* FIXME: better prefix to distinguish from
10085 * local prompts? */
10086 s->cur_prompt->name =
10087 dupprintf("SSH server: %.*s", name_len, name);
10088 s->cur_prompt->name_reqd = TRUE;
10090 s->cur_prompt->name =
10091 dupstr("SSH server authentication");
10092 s->cur_prompt->name_reqd = FALSE;
10094 /* We add a prefix to try to make it clear that a prompt
10095 * has come from the server.
10096 * FIXME: ugly to print "Using..." in prompt _every_
10097 * time round. Can this be done more subtly? */
10098 /* Special case: for reasons best known to themselves,
10099 * some servers send k-i requests with no prompts and
10100 * nothing to display. Keep quiet in this case. */
10101 if (s->num_prompts || name_len || inst_len) {
10102 s->cur_prompt->instruction =
10103 dupprintf("Using keyboard-interactive authentication.%s%.*s",
10104 inst_len ? "\n" : "", inst_len, inst);
10105 s->cur_prompt->instr_reqd = TRUE;
10107 s->cur_prompt->instr_reqd = FALSE;
10111 * Display any instructions, and get the user's
10115 int ret; /* not live over crReturn */
10116 ret = get_userpass_input(s->cur_prompt, NULL, 0);
10119 crWaitUntilV(!pktin);
10120 ret = get_userpass_input(s->cur_prompt, in, inlen);
10125 * Failed to get responses. Terminate.
10127 free_prompts(s->cur_prompt);
10128 ssh_disconnect(ssh, NULL, "Unable to authenticate",
10129 SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER,
10136 * Send the response(s) to the server.
10138 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_INFO_RESPONSE);
10139 ssh2_pkt_adduint32(s->pktout, s->num_prompts);
10140 for (i=0; i < s->num_prompts; i++) {
10141 ssh2_pkt_addstring(s->pktout,
10142 s->cur_prompt->prompts[i]->result);
10144 ssh2_pkt_send_with_padding(ssh, s->pktout, 256);
10147 * Free the prompts structure from this iteration.
10148 * If there's another, a new one will be allocated
10149 * when we return to the top of this while loop.
10151 free_prompts(s->cur_prompt);
10154 * Get the next packet in case it's another
10157 crWaitUntilV(pktin);
10162 * We should have SUCCESS or FAILURE now.
10166 } else if (s->can_passwd) {
10169 * Plain old password authentication.
10171 int ret; /* not live over crReturn */
10172 int changereq_first_time; /* not live over crReturn */
10174 ssh->pkt_actx = SSH2_PKTCTX_PASSWORD;
10176 s->cur_prompt = new_prompts(ssh->frontend);
10177 s->cur_prompt->to_server = TRUE;
10178 s->cur_prompt->name = dupstr("SSH password");
10179 add_prompt(s->cur_prompt, dupprintf("%s@%s's password: ",
10184 ret = get_userpass_input(s->cur_prompt, NULL, 0);
10187 crWaitUntilV(!pktin);
10188 ret = get_userpass_input(s->cur_prompt, in, inlen);
10193 * Failed to get responses. Terminate.
10195 free_prompts(s->cur_prompt);
10196 ssh_disconnect(ssh, NULL, "Unable to authenticate",
10197 SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER,
10202 * Squirrel away the password. (We may need it later if
10203 * asked to change it.)
10205 s->password = dupstr(s->cur_prompt->prompts[0]->result);
10206 free_prompts(s->cur_prompt);
10209 * Send the password packet.
10211 * We pad out the password packet to 256 bytes to make
10212 * it harder for an attacker to find the length of the
10215 * Anyone using a password longer than 256 bytes
10216 * probably doesn't have much to worry about from
10217 * people who find out how long their password is!
10219 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
10220 ssh2_pkt_addstring(s->pktout, ssh->username);
10221 ssh2_pkt_addstring(s->pktout, "ssh-connection");
10222 /* service requested */
10223 ssh2_pkt_addstring(s->pktout, "password");
10224 ssh2_pkt_addbool(s->pktout, FALSE);
10225 ssh2_pkt_addstring(s->pktout, s->password);
10226 ssh2_pkt_send_with_padding(ssh, s->pktout, 256);
10227 logevent("Sent password");
10228 s->type = AUTH_TYPE_PASSWORD;
10231 * Wait for next packet, in case it's a password change
10234 crWaitUntilV(pktin);
10235 changereq_first_time = TRUE;
10237 while (pktin->type == SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ) {
10240 * We're being asked for a new password
10241 * (perhaps not for the first time).
10242 * Loop until the server accepts it.
10245 int got_new = FALSE; /* not live over crReturn */
10246 char *prompt; /* not live over crReturn */
10247 int prompt_len; /* not live over crReturn */
10251 if (changereq_first_time)
10252 msg = "Server requested password change";
10254 msg = "Server rejected new password";
10256 c_write_str(ssh, msg);
10257 c_write_str(ssh, "\r\n");
10260 ssh_pkt_getstring(pktin, &prompt, &prompt_len);
10262 s->cur_prompt = new_prompts(ssh->frontend);
10263 s->cur_prompt->to_server = TRUE;
10264 s->cur_prompt->name = dupstr("New SSH password");
10265 s->cur_prompt->instruction =
10266 dupprintf("%.*s", prompt_len, prompt);
10267 s->cur_prompt->instr_reqd = TRUE;
10269 * There's no explicit requirement in the protocol
10270 * for the "old" passwords in the original and
10271 * password-change messages to be the same, and
10272 * apparently some Cisco kit supports password change
10273 * by the user entering a blank password originally
10274 * and the real password subsequently, so,
10275 * reluctantly, we prompt for the old password again.
10277 * (On the other hand, some servers don't even bother
10278 * to check this field.)
10280 add_prompt(s->cur_prompt,
10281 dupstr("Current password (blank for previously entered password): "),
10283 add_prompt(s->cur_prompt, dupstr("Enter new password: "),
10285 add_prompt(s->cur_prompt, dupstr("Confirm new password: "),
10289 * Loop until the user manages to enter the same
10294 ret = get_userpass_input(s->cur_prompt, NULL, 0);
10297 crWaitUntilV(!pktin);
10298 ret = get_userpass_input(s->cur_prompt, in, inlen);
10303 * Failed to get responses. Terminate.
10305 /* burn the evidence */
10306 free_prompts(s->cur_prompt);
10307 smemclr(s->password, strlen(s->password));
10308 sfree(s->password);
10309 ssh_disconnect(ssh, NULL, "Unable to authenticate",
10310 SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER,
10316 * If the user specified a new original password
10317 * (IYSWIM), overwrite any previously specified
10319 * (A side effect is that the user doesn't have to
10320 * re-enter it if they louse up the new password.)
10322 if (s->cur_prompt->prompts[0]->result[0]) {
10323 smemclr(s->password, strlen(s->password));
10324 /* burn the evidence */
10325 sfree(s->password);
10327 dupstr(s->cur_prompt->prompts[0]->result);
10331 * Check the two new passwords match.
10333 got_new = (strcmp(s->cur_prompt->prompts[1]->result,
10334 s->cur_prompt->prompts[2]->result)
10337 /* They don't. Silly user. */
10338 c_write_str(ssh, "Passwords do not match\r\n");
10343 * Send the new password (along with the old one).
10344 * (see above for padding rationale)
10346 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
10347 ssh2_pkt_addstring(s->pktout, ssh->username);
10348 ssh2_pkt_addstring(s->pktout, "ssh-connection");
10349 /* service requested */
10350 ssh2_pkt_addstring(s->pktout, "password");
10351 ssh2_pkt_addbool(s->pktout, TRUE);
10352 ssh2_pkt_addstring(s->pktout, s->password);
10353 ssh2_pkt_addstring(s->pktout,
10354 s->cur_prompt->prompts[1]->result);
10355 free_prompts(s->cur_prompt);
10356 ssh2_pkt_send_with_padding(ssh, s->pktout, 256);
10357 logevent("Sent new password");
10360 * Now see what the server has to say about it.
10361 * (If it's CHANGEREQ again, it's not happy with the
10364 crWaitUntilV(pktin);
10365 changereq_first_time = FALSE;
10370 * We need to reexamine the current pktin at the top
10371 * of the loop. Either:
10372 * - we weren't asked to change password at all, in
10373 * which case it's a SUCCESS or FAILURE with the
10375 * - we sent a new password, and the server was
10376 * either OK with it (SUCCESS or FAILURE w/partial
10377 * success) or unhappy with the _old_ password
10378 * (FAILURE w/o partial success)
10379 * In any of these cases, we go back to the top of
10380 * the loop and start again.
10385 * We don't need the old password any more, in any
10386 * case. Burn the evidence.
10388 smemclr(s->password, strlen(s->password));
10389 sfree(s->password);
10392 char *str = dupprintf("No supported authentication methods available"
10393 " (server sent: %.*s)",
10396 ssh_disconnect(ssh, str,
10397 "No supported authentication methods available",
10398 SSH2_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE,
10408 ssh->packet_dispatch[SSH2_MSG_USERAUTH_BANNER] = NULL;
10410 /* Clear up various bits and pieces from authentication. */
10411 if (s->publickey_blob) {
10412 sfree(s->publickey_algorithm);
10413 sfree(s->publickey_blob);
10414 sfree(s->publickey_comment);
10416 if (s->agent_response)
10417 sfree(s->agent_response);
10419 if (s->userauth_success && !ssh->bare_connection) {
10421 * We've just received USERAUTH_SUCCESS, and we haven't sent any
10422 * packets since. Signal the transport layer to consider enacting
10423 * delayed compression.
10425 * (Relying on we_are_in is not sufficient, as
10426 * draft-miller-secsh-compression-delayed is quite clear that it
10427 * triggers on USERAUTH_SUCCESS specifically, and we_are_in can
10428 * become set for other reasons.)
10430 do_ssh2_transport(ssh, "enabling delayed compression", -2, NULL);
10433 ssh->channels = newtree234(ssh_channelcmp);
10436 * Set up handlers for some connection protocol messages, so we
10437 * don't have to handle them repeatedly in this coroutine.
10439 ssh->packet_dispatch[SSH2_MSG_CHANNEL_WINDOW_ADJUST] =
10440 ssh2_msg_channel_window_adjust;
10441 ssh->packet_dispatch[SSH2_MSG_GLOBAL_REQUEST] =
10442 ssh2_msg_global_request;
10445 * Create the main session channel.
10447 if (conf_get_int(ssh->conf, CONF_ssh_no_shell)) {
10448 ssh->mainchan = NULL;
10450 ssh->mainchan = snew(struct ssh_channel);
10451 ssh->mainchan->ssh = ssh;
10452 ssh2_channel_init(ssh->mainchan);
10454 if (*conf_get_str(ssh->conf, CONF_ssh_nc_host)) {
10456 * Just start a direct-tcpip channel and use it as the main
10459 ssh_send_port_open(ssh->mainchan,
10460 conf_get_str(ssh->conf, CONF_ssh_nc_host),
10461 conf_get_int(ssh->conf, CONF_ssh_nc_port),
10463 ssh->ncmode = TRUE;
10465 s->pktout = ssh2_chanopen_init(ssh->mainchan, "session");
10466 logevent("Opening session as main channel");
10467 ssh2_pkt_send(ssh, s->pktout);
10468 ssh->ncmode = FALSE;
10470 crWaitUntilV(pktin);
10471 if (pktin->type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
10472 bombout(("Server refused to open channel"));
10474 /* FIXME: error data comes back in FAILURE packet */
10476 if (ssh_pkt_getuint32(pktin) != ssh->mainchan->localid) {
10477 bombout(("Server's channel confirmation cited wrong channel"));
10480 ssh->mainchan->remoteid = ssh_pkt_getuint32(pktin);
10481 ssh->mainchan->halfopen = FALSE;
10482 ssh->mainchan->type = CHAN_MAINSESSION;
10483 ssh->mainchan->v.v2.remwindow = ssh_pkt_getuint32(pktin);
10484 ssh->mainchan->v.v2.remmaxpkt = ssh_pkt_getuint32(pktin);
10485 add234(ssh->channels, ssh->mainchan);
10486 update_specials_menu(ssh->frontend);
10487 logevent("Opened main channel");
10491 * Now we have a channel, make dispatch table entries for
10492 * general channel-based messages.
10494 ssh->packet_dispatch[SSH2_MSG_CHANNEL_DATA] =
10495 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EXTENDED_DATA] =
10496 ssh2_msg_channel_data;
10497 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EOF] = ssh2_msg_channel_eof;
10498 ssh->packet_dispatch[SSH2_MSG_CHANNEL_CLOSE] = ssh2_msg_channel_close;
10499 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_CONFIRMATION] =
10500 ssh2_msg_channel_open_confirmation;
10501 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_FAILURE] =
10502 ssh2_msg_channel_open_failure;
10503 ssh->packet_dispatch[SSH2_MSG_CHANNEL_REQUEST] =
10504 ssh2_msg_channel_request;
10505 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN] =
10506 ssh2_msg_channel_open;
10507 ssh->packet_dispatch[SSH2_MSG_CHANNEL_SUCCESS] = ssh2_msg_channel_response;
10508 ssh->packet_dispatch[SSH2_MSG_CHANNEL_FAILURE] = ssh2_msg_channel_response;
10511 * Now the connection protocol is properly up and running, with
10512 * all those dispatch table entries, so it's safe to let
10513 * downstreams start trying to open extra channels through us.
10515 if (ssh->connshare)
10516 share_activate(ssh->connshare, ssh->v_s);
10518 if (ssh->mainchan && ssh_is_simple(ssh)) {
10520 * This message indicates to the server that we promise
10521 * not to try to run any other channel in parallel with
10522 * this one, so it's safe for it to advertise a very large
10523 * window and leave the flow control to TCP.
10525 s->pktout = ssh2_chanreq_init(ssh->mainchan,
10526 "simple@putty.projects.tartarus.org",
10528 ssh2_pkt_send(ssh, s->pktout);
10532 * Enable port forwardings.
10534 ssh_setup_portfwd(ssh, ssh->conf);
10536 if (ssh->mainchan && !ssh->ncmode) {
10538 * Send the CHANNEL_REQUESTS for the main session channel.
10539 * Each one is handled by its own little asynchronous
10543 /* Potentially enable X11 forwarding. */
10544 if (conf_get_int(ssh->conf, CONF_x11_forward)) {
10546 x11_setup_display(conf_get_str(ssh->conf, CONF_x11_display),
10548 if (!ssh->x11disp) {
10549 /* FIXME: return an error message from x11_setup_display */
10550 logevent("X11 forwarding not enabled: unable to"
10551 " initialise X display");
10553 ssh->x11auth = x11_invent_fake_auth
10554 (ssh->x11authtree, conf_get_int(ssh->conf, CONF_x11_auth));
10555 ssh->x11auth->disp = ssh->x11disp;
10557 ssh2_setup_x11(ssh->mainchan, NULL, NULL);
10561 /* Potentially enable agent forwarding. */
10562 if (ssh_agent_forwarding_permitted(ssh))
10563 ssh2_setup_agent(ssh->mainchan, NULL, NULL);
10565 /* Now allocate a pty for the session. */
10566 if (!conf_get_int(ssh->conf, CONF_nopty))
10567 ssh2_setup_pty(ssh->mainchan, NULL, NULL);
10569 /* Send environment variables. */
10570 ssh2_setup_env(ssh->mainchan, NULL, NULL);
10573 * Start a shell or a remote command. We may have to attempt
10574 * this twice if the config data has provided a second choice
10581 if (ssh->fallback_cmd) {
10582 subsys = conf_get_int(ssh->conf, CONF_ssh_subsys2);
10583 cmd = conf_get_str(ssh->conf, CONF_remote_cmd2);
10585 subsys = conf_get_int(ssh->conf, CONF_ssh_subsys);
10586 cmd = conf_get_str(ssh->conf, CONF_remote_cmd);
10590 s->pktout = ssh2_chanreq_init(ssh->mainchan, "subsystem",
10591 ssh2_response_authconn, NULL);
10592 ssh2_pkt_addstring(s->pktout, cmd);
10594 s->pktout = ssh2_chanreq_init(ssh->mainchan, "exec",
10595 ssh2_response_authconn, NULL);
10596 ssh2_pkt_addstring(s->pktout, cmd);
10598 s->pktout = ssh2_chanreq_init(ssh->mainchan, "shell",
10599 ssh2_response_authconn, NULL);
10601 ssh2_pkt_send(ssh, s->pktout);
10603 crWaitUntilV(pktin);
10605 if (pktin->type != SSH2_MSG_CHANNEL_SUCCESS) {
10606 if (pktin->type != SSH2_MSG_CHANNEL_FAILURE) {
10607 bombout(("Unexpected response to shell/command request:"
10608 " packet type %d", pktin->type));
10612 * We failed to start the command. If this is the
10613 * fallback command, we really are finished; if it's
10614 * not, and if the fallback command exists, try falling
10615 * back to it before complaining.
10617 if (!ssh->fallback_cmd &&
10618 *conf_get_str(ssh->conf, CONF_remote_cmd2)) {
10619 logevent("Primary command failed; attempting fallback");
10620 ssh->fallback_cmd = TRUE;
10623 bombout(("Server refused to start a shell/command"));
10626 logevent("Started a shell/command");
10631 ssh->editing = ssh->echoing = TRUE;
10634 ssh->state = SSH_STATE_SESSION;
10635 if (ssh->size_needed)
10636 ssh_size(ssh, ssh->term_width, ssh->term_height);
10637 if (ssh->eof_needed)
10638 ssh_special(ssh, TS_EOF);
10644 ldisc_echoedit_update(ssh->ldisc); /* cause ldisc to notice changes */
10649 s->try_send = FALSE;
10653 * _All_ the connection-layer packets we expect to
10654 * receive are now handled by the dispatch table.
10655 * Anything that reaches here must be bogus.
10658 bombout(("Strange packet received: type %d", pktin->type));
10660 } else if (ssh->mainchan) {
10662 * We have spare data. Add it to the channel buffer.
10664 ssh2_add_channel_data(ssh->mainchan, (char *)in, inlen);
10665 s->try_send = TRUE;
10669 struct ssh_channel *c;
10671 * Try to send data on all channels if we can.
10673 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++)
10674 if (c->type != CHAN_SHARING)
10675 ssh2_try_send_and_unthrottle(ssh, c);
10683 * Handlers for SSH-2 messages that might arrive at any moment.
10685 static void ssh2_msg_disconnect(Ssh ssh, struct Packet *pktin)
10687 /* log reason code in disconnect message */
10689 int reason, msglen;
10691 reason = ssh_pkt_getuint32(pktin);
10692 ssh_pkt_getstring(pktin, &msg, &msglen);
10694 if (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) {
10695 buf = dupprintf("Received disconnect message (%s)",
10696 ssh2_disconnect_reasons[reason]);
10698 buf = dupprintf("Received disconnect message (unknown"
10699 " type %d)", reason);
10703 buf = dupprintf("Disconnection message text: %.*s",
10706 bombout(("Server sent disconnect message\ntype %d (%s):\n\"%.*s\"",
10708 (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) ?
10709 ssh2_disconnect_reasons[reason] : "unknown",
10714 static void ssh2_msg_debug(Ssh ssh, struct Packet *pktin)
10716 /* log the debug message */
10720 /* XXX maybe we should actually take notice of the return value */
10721 ssh2_pkt_getbool(pktin);
10722 ssh_pkt_getstring(pktin, &msg, &msglen);
10724 logeventf(ssh, "Remote debug message: %.*s", msglen, msg);
10727 static void ssh2_msg_transport(Ssh ssh, struct Packet *pktin)
10729 do_ssh2_transport(ssh, NULL, 0, pktin);
10733 * Called if we receive a packet that isn't allowed by the protocol.
10734 * This only applies to packets whose meaning PuTTY understands.
10735 * Entirely unknown packets are handled below.
10737 static void ssh2_msg_unexpected(Ssh ssh, struct Packet *pktin)
10739 char *buf = dupprintf("Server protocol violation: unexpected %s packet",
10740 ssh2_pkt_type(ssh->pkt_kctx, ssh->pkt_actx,
10742 ssh_disconnect(ssh, NULL, buf, SSH2_DISCONNECT_PROTOCOL_ERROR, FALSE);
10746 static void ssh2_msg_something_unimplemented(Ssh ssh, struct Packet *pktin)
10748 struct Packet *pktout;
10749 pktout = ssh2_pkt_init(SSH2_MSG_UNIMPLEMENTED);
10750 ssh2_pkt_adduint32(pktout, pktin->sequence);
10752 * UNIMPLEMENTED messages MUST appear in the same order as the
10753 * messages they respond to. Hence, never queue them.
10755 ssh2_pkt_send_noqueue(ssh, pktout);
10759 * Handle the top-level SSH-2 protocol.
10761 static void ssh2_protocol_setup(Ssh ssh)
10766 * Most messages cause SSH2_MSG_UNIMPLEMENTED.
10768 for (i = 0; i < 256; i++)
10769 ssh->packet_dispatch[i] = ssh2_msg_something_unimplemented;
10772 * Initially, we only accept transport messages (and a few generic
10773 * ones). do_ssh2_authconn will add more when it starts.
10774 * Messages that are understood but not currently acceptable go to
10775 * ssh2_msg_unexpected.
10777 ssh->packet_dispatch[SSH2_MSG_UNIMPLEMENTED] = ssh2_msg_unexpected;
10778 ssh->packet_dispatch[SSH2_MSG_SERVICE_REQUEST] = ssh2_msg_unexpected;
10779 ssh->packet_dispatch[SSH2_MSG_SERVICE_ACCEPT] = ssh2_msg_unexpected;
10780 ssh->packet_dispatch[SSH2_MSG_KEXINIT] = ssh2_msg_transport;
10781 ssh->packet_dispatch[SSH2_MSG_NEWKEYS] = ssh2_msg_transport;
10782 ssh->packet_dispatch[SSH2_MSG_KEXDH_INIT] = ssh2_msg_transport;
10783 ssh->packet_dispatch[SSH2_MSG_KEXDH_REPLY] = ssh2_msg_transport;
10784 /* ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_REQUEST] = ssh2_msg_transport; duplicate case value */
10785 /* ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_GROUP] = ssh2_msg_transport; duplicate case value */
10786 ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_INIT] = ssh2_msg_transport;
10787 ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_REPLY] = ssh2_msg_transport;
10788 ssh->packet_dispatch[SSH2_MSG_USERAUTH_REQUEST] = ssh2_msg_unexpected;
10789 ssh->packet_dispatch[SSH2_MSG_USERAUTH_FAILURE] = ssh2_msg_unexpected;
10790 ssh->packet_dispatch[SSH2_MSG_USERAUTH_SUCCESS] = ssh2_msg_unexpected;
10791 ssh->packet_dispatch[SSH2_MSG_USERAUTH_BANNER] = ssh2_msg_unexpected;
10792 ssh->packet_dispatch[SSH2_MSG_USERAUTH_PK_OK] = ssh2_msg_unexpected;
10793 /* ssh->packet_dispatch[SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ] = ssh2_msg_unexpected; duplicate case value */
10794 /* ssh->packet_dispatch[SSH2_MSG_USERAUTH_INFO_REQUEST] = ssh2_msg_unexpected; duplicate case value */
10795 ssh->packet_dispatch[SSH2_MSG_USERAUTH_INFO_RESPONSE] = ssh2_msg_unexpected;
10796 ssh->packet_dispatch[SSH2_MSG_GLOBAL_REQUEST] = ssh2_msg_unexpected;
10797 ssh->packet_dispatch[SSH2_MSG_REQUEST_SUCCESS] = ssh2_msg_unexpected;
10798 ssh->packet_dispatch[SSH2_MSG_REQUEST_FAILURE] = ssh2_msg_unexpected;
10799 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN] = ssh2_msg_unexpected;
10800 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_CONFIRMATION] = ssh2_msg_unexpected;
10801 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_FAILURE] = ssh2_msg_unexpected;
10802 ssh->packet_dispatch[SSH2_MSG_CHANNEL_WINDOW_ADJUST] = ssh2_msg_unexpected;
10803 ssh->packet_dispatch[SSH2_MSG_CHANNEL_DATA] = ssh2_msg_unexpected;
10804 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EXTENDED_DATA] = ssh2_msg_unexpected;
10805 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EOF] = ssh2_msg_unexpected;
10806 ssh->packet_dispatch[SSH2_MSG_CHANNEL_CLOSE] = ssh2_msg_unexpected;
10807 ssh->packet_dispatch[SSH2_MSG_CHANNEL_REQUEST] = ssh2_msg_unexpected;
10808 ssh->packet_dispatch[SSH2_MSG_CHANNEL_SUCCESS] = ssh2_msg_unexpected;
10809 ssh->packet_dispatch[SSH2_MSG_CHANNEL_FAILURE] = ssh2_msg_unexpected;
10812 * These messages have a special handler from the start.
10814 ssh->packet_dispatch[SSH2_MSG_DISCONNECT] = ssh2_msg_disconnect;
10815 ssh->packet_dispatch[SSH2_MSG_IGNORE] = ssh_msg_ignore; /* shared with SSH-1 */
10816 ssh->packet_dispatch[SSH2_MSG_DEBUG] = ssh2_msg_debug;
10819 static void ssh2_bare_connection_protocol_setup(Ssh ssh)
10824 * Most messages cause SSH2_MSG_UNIMPLEMENTED.
10826 for (i = 0; i < 256; i++)
10827 ssh->packet_dispatch[i] = ssh2_msg_something_unimplemented;
10830 * Initially, we set all ssh-connection messages to 'unexpected';
10831 * do_ssh2_authconn will fill things in properly. We also handle a
10832 * couple of messages from the transport protocol which aren't
10833 * related to key exchange (UNIMPLEMENTED, IGNORE, DEBUG,
10836 ssh->packet_dispatch[SSH2_MSG_GLOBAL_REQUEST] = ssh2_msg_unexpected;
10837 ssh->packet_dispatch[SSH2_MSG_REQUEST_SUCCESS] = ssh2_msg_unexpected;
10838 ssh->packet_dispatch[SSH2_MSG_REQUEST_FAILURE] = ssh2_msg_unexpected;
10839 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN] = ssh2_msg_unexpected;
10840 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_CONFIRMATION] = ssh2_msg_unexpected;
10841 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_FAILURE] = ssh2_msg_unexpected;
10842 ssh->packet_dispatch[SSH2_MSG_CHANNEL_WINDOW_ADJUST] = ssh2_msg_unexpected;
10843 ssh->packet_dispatch[SSH2_MSG_CHANNEL_DATA] = ssh2_msg_unexpected;
10844 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EXTENDED_DATA] = ssh2_msg_unexpected;
10845 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EOF] = ssh2_msg_unexpected;
10846 ssh->packet_dispatch[SSH2_MSG_CHANNEL_CLOSE] = ssh2_msg_unexpected;
10847 ssh->packet_dispatch[SSH2_MSG_CHANNEL_REQUEST] = ssh2_msg_unexpected;
10848 ssh->packet_dispatch[SSH2_MSG_CHANNEL_SUCCESS] = ssh2_msg_unexpected;
10849 ssh->packet_dispatch[SSH2_MSG_CHANNEL_FAILURE] = ssh2_msg_unexpected;
10851 ssh->packet_dispatch[SSH2_MSG_UNIMPLEMENTED] = ssh2_msg_unexpected;
10854 * These messages have a special handler from the start.
10856 ssh->packet_dispatch[SSH2_MSG_DISCONNECT] = ssh2_msg_disconnect;
10857 ssh->packet_dispatch[SSH2_MSG_IGNORE] = ssh_msg_ignore;
10858 ssh->packet_dispatch[SSH2_MSG_DEBUG] = ssh2_msg_debug;
10861 static void ssh2_timer(void *ctx, unsigned long now)
10863 Ssh ssh = (Ssh)ctx;
10865 if (ssh->state == SSH_STATE_CLOSED)
10868 if (!ssh->kex_in_progress && !ssh->bare_connection &&
10869 conf_get_int(ssh->conf, CONF_ssh_rekey_time) != 0 &&
10870 now == ssh->next_rekey) {
10871 do_ssh2_transport(ssh, "timeout", -1, NULL);
10875 static void ssh2_protocol(Ssh ssh, const void *vin, int inlen,
10876 struct Packet *pktin)
10878 const unsigned char *in = (const unsigned char *)vin;
10879 if (ssh->state == SSH_STATE_CLOSED)
10883 ssh->incoming_data_size += pktin->encrypted_len;
10884 if (!ssh->kex_in_progress &&
10885 ssh->max_data_size != 0 &&
10886 ssh->incoming_data_size > ssh->max_data_size)
10887 do_ssh2_transport(ssh, "too much data received", -1, NULL);
10891 ssh->packet_dispatch[pktin->type](ssh, pktin);
10892 else if (!ssh->protocol_initial_phase_done)
10893 do_ssh2_transport(ssh, in, inlen, pktin);
10895 do_ssh2_authconn(ssh, in, inlen, pktin);
10898 static void ssh2_bare_connection_protocol(Ssh ssh, const void *vin, int inlen,
10899 struct Packet *pktin)
10901 const unsigned char *in = (const unsigned char *)vin;
10902 if (ssh->state == SSH_STATE_CLOSED)
10906 ssh->packet_dispatch[pktin->type](ssh, pktin);
10908 do_ssh2_authconn(ssh, in, inlen, pktin);
10911 static void ssh_cache_conf_values(Ssh ssh)
10913 ssh->logomitdata = conf_get_int(ssh->conf, CONF_logomitdata);
10917 * Called to set up the connection.
10919 * Returns an error message, or NULL on success.
10921 static const char *ssh_init(void *frontend_handle, void **backend_handle,
10923 const char *host, int port, char **realhost,
10924 int nodelay, int keepalive)
10929 ssh = snew(struct ssh_tag);
10930 ssh->conf = conf_copy(conf);
10931 ssh_cache_conf_values(ssh);
10932 ssh->version = 0; /* when not ready yet */
10934 ssh->cipher = NULL;
10935 ssh->v1_cipher_ctx = NULL;
10936 ssh->crcda_ctx = NULL;
10937 ssh->cscipher = NULL;
10938 ssh->cs_cipher_ctx = NULL;
10939 ssh->sccipher = NULL;
10940 ssh->sc_cipher_ctx = NULL;
10942 ssh->cs_mac_ctx = NULL;
10944 ssh->sc_mac_ctx = NULL;
10945 ssh->cscomp = NULL;
10946 ssh->cs_comp_ctx = NULL;
10947 ssh->sccomp = NULL;
10948 ssh->sc_comp_ctx = NULL;
10950 ssh->kex_ctx = NULL;
10951 ssh->hostkey = NULL;
10952 ssh->hostkey_str = NULL;
10953 ssh->exitcode = -1;
10954 ssh->close_expected = FALSE;
10955 ssh->clean_exit = FALSE;
10956 ssh->state = SSH_STATE_PREPACKET;
10957 ssh->size_needed = FALSE;
10958 ssh->eof_needed = FALSE;
10960 ssh->logctx = NULL;
10961 ssh->deferred_send_data = NULL;
10962 ssh->deferred_len = 0;
10963 ssh->deferred_size = 0;
10964 ssh->fallback_cmd = 0;
10965 ssh->pkt_kctx = SSH2_PKTCTX_NOKEX;
10966 ssh->pkt_actx = SSH2_PKTCTX_NOAUTH;
10967 ssh->x11disp = NULL;
10968 ssh->x11auth = NULL;
10969 ssh->x11authtree = newtree234(x11_authcmp);
10970 ssh->v1_compressing = FALSE;
10971 ssh->v2_outgoing_sequence = 0;
10972 ssh->ssh1_rdpkt_crstate = 0;
10973 ssh->ssh2_rdpkt_crstate = 0;
10974 ssh->ssh2_bare_rdpkt_crstate = 0;
10975 ssh->ssh_gotdata_crstate = 0;
10976 ssh->do_ssh1_connection_crstate = 0;
10977 ssh->do_ssh_init_state = NULL;
10978 ssh->do_ssh_connection_init_state = NULL;
10979 ssh->do_ssh1_login_state = NULL;
10980 ssh->do_ssh2_transport_state = NULL;
10981 ssh->do_ssh2_authconn_state = NULL;
10984 ssh->mainchan = NULL;
10985 ssh->throttled_all = 0;
10986 ssh->v1_stdout_throttling = 0;
10988 ssh->queuelen = ssh->queuesize = 0;
10989 ssh->queueing = FALSE;
10990 ssh->qhead = ssh->qtail = NULL;
10991 ssh->deferred_rekey_reason = NULL;
10992 bufchain_init(&ssh->queued_incoming_data);
10993 ssh->frozen = FALSE;
10994 ssh->username = NULL;
10995 ssh->sent_console_eof = FALSE;
10996 ssh->got_pty = FALSE;
10997 ssh->bare_connection = FALSE;
10998 ssh->X11_fwd_enabled = FALSE;
10999 ssh->connshare = NULL;
11000 ssh->attempting_connshare = FALSE;
11002 *backend_handle = ssh;
11005 if (crypto_startup() == 0)
11006 return "Microsoft high encryption pack not installed!";
11009 ssh->frontend = frontend_handle;
11010 ssh->term_width = conf_get_int(ssh->conf, CONF_width);
11011 ssh->term_height = conf_get_int(ssh->conf, CONF_height);
11013 ssh->channels = NULL;
11014 ssh->rportfwds = NULL;
11015 ssh->portfwds = NULL;
11020 ssh->conn_throttle_count = 0;
11021 ssh->overall_bufsize = 0;
11022 ssh->fallback_cmd = 0;
11024 ssh->protocol = NULL;
11026 ssh->protocol_initial_phase_done = FALSE;
11028 ssh->pinger = NULL;
11030 ssh->incoming_data_size = ssh->outgoing_data_size =
11031 ssh->deferred_data_size = 0L;
11032 ssh->max_data_size = parse_blocksize(conf_get_str(ssh->conf,
11033 CONF_ssh_rekey_data));
11034 ssh->kex_in_progress = FALSE;
11037 ssh->gsslibs = NULL;
11040 random_ref(); /* do this now - may be needed by sharing setup code */
11042 p = connect_to_host(ssh, host, port, realhost, nodelay, keepalive);
11051 static void ssh_free(void *handle)
11053 Ssh ssh = (Ssh) handle;
11054 struct ssh_channel *c;
11055 struct ssh_rportfwd *pf;
11056 struct X11FakeAuth *auth;
11058 if (ssh->v1_cipher_ctx)
11059 ssh->cipher->free_context(ssh->v1_cipher_ctx);
11060 if (ssh->cs_cipher_ctx)
11061 ssh->cscipher->free_context(ssh->cs_cipher_ctx);
11062 if (ssh->sc_cipher_ctx)
11063 ssh->sccipher->free_context(ssh->sc_cipher_ctx);
11064 if (ssh->cs_mac_ctx)
11065 ssh->csmac->free_context(ssh->cs_mac_ctx);
11066 if (ssh->sc_mac_ctx)
11067 ssh->scmac->free_context(ssh->sc_mac_ctx);
11068 if (ssh->cs_comp_ctx) {
11070 ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
11072 zlib_compress_cleanup(ssh->cs_comp_ctx);
11074 if (ssh->sc_comp_ctx) {
11076 ssh->sccomp->decompress_cleanup(ssh->sc_comp_ctx);
11078 zlib_decompress_cleanup(ssh->sc_comp_ctx);
11081 dh_cleanup(ssh->kex_ctx);
11082 sfree(ssh->savedhost);
11084 while (ssh->queuelen-- > 0)
11085 ssh_free_packet(ssh->queue[ssh->queuelen]);
11088 while (ssh->qhead) {
11089 struct queued_handler *qh = ssh->qhead;
11090 ssh->qhead = qh->next;
11093 ssh->qhead = ssh->qtail = NULL;
11095 if (ssh->channels) {
11096 while ((c = delpos234(ssh->channels, 0)) != NULL) {
11099 if (c->u.x11.xconn != NULL)
11100 x11_close(c->u.x11.xconn);
11102 case CHAN_SOCKDATA:
11103 case CHAN_SOCKDATA_DORMANT:
11104 if (c->u.pfd.pf != NULL)
11105 pfd_close(c->u.pfd.pf);
11108 if (ssh->version == 2) {
11109 struct outstanding_channel_request *ocr, *nocr;
11110 ocr = c->v.v2.chanreq_head;
11112 ocr->handler(c, NULL, ocr->ctx);
11117 bufchain_clear(&c->v.v2.outbuffer);
11121 freetree234(ssh->channels);
11122 ssh->channels = NULL;
11125 if (ssh->connshare)
11126 sharestate_free(ssh->connshare);
11128 if (ssh->rportfwds) {
11129 while ((pf = delpos234(ssh->rportfwds, 0)) != NULL)
11131 freetree234(ssh->rportfwds);
11132 ssh->rportfwds = NULL;
11134 sfree(ssh->deferred_send_data);
11136 x11_free_display(ssh->x11disp);
11137 while ((auth = delpos234(ssh->x11authtree, 0)) != NULL)
11138 x11_free_fake_auth(auth);
11139 freetree234(ssh->x11authtree);
11140 sfree(ssh->do_ssh_init_state);
11141 sfree(ssh->do_ssh1_login_state);
11142 sfree(ssh->do_ssh2_transport_state);
11143 sfree(ssh->do_ssh2_authconn_state);
11146 sfree(ssh->fullhostname);
11147 sfree(ssh->hostkey_str);
11148 if (ssh->crcda_ctx) {
11149 crcda_free_context(ssh->crcda_ctx);
11150 ssh->crcda_ctx = NULL;
11153 ssh_do_close(ssh, TRUE);
11154 expire_timer_context(ssh);
11156 pinger_free(ssh->pinger);
11157 bufchain_clear(&ssh->queued_incoming_data);
11158 sfree(ssh->username);
11159 conf_free(ssh->conf);
11162 ssh_gss_cleanup(ssh->gsslibs);
11170 * Reconfigure the SSH backend.
11172 static void ssh_reconfig(void *handle, Conf *conf)
11174 Ssh ssh = (Ssh) handle;
11175 const char *rekeying = NULL;
11176 int rekey_mandatory = FALSE;
11177 unsigned long old_max_data_size;
11180 pinger_reconfig(ssh->pinger, ssh->conf, conf);
11182 ssh_setup_portfwd(ssh, conf);
11184 rekey_time = conf_get_int(conf, CONF_ssh_rekey_time);
11185 if (conf_get_int(ssh->conf, CONF_ssh_rekey_time) != rekey_time &&
11187 unsigned long new_next = ssh->last_rekey + rekey_time*60*TICKSPERSEC;
11188 unsigned long now = GETTICKCOUNT();
11190 if (now - ssh->last_rekey > rekey_time*60*TICKSPERSEC) {
11191 rekeying = "timeout shortened";
11193 ssh->next_rekey = schedule_timer(new_next - now, ssh2_timer, ssh);
11197 old_max_data_size = ssh->max_data_size;
11198 ssh->max_data_size = parse_blocksize(conf_get_str(ssh->conf,
11199 CONF_ssh_rekey_data));
11200 if (old_max_data_size != ssh->max_data_size &&
11201 ssh->max_data_size != 0) {
11202 if (ssh->outgoing_data_size > ssh->max_data_size ||
11203 ssh->incoming_data_size > ssh->max_data_size)
11204 rekeying = "data limit lowered";
11207 if (conf_get_int(ssh->conf, CONF_compression) !=
11208 conf_get_int(conf, CONF_compression)) {
11209 rekeying = "compression setting changed";
11210 rekey_mandatory = TRUE;
11213 for (i = 0; i < CIPHER_MAX; i++)
11214 if (conf_get_int_int(ssh->conf, CONF_ssh_cipherlist, i) !=
11215 conf_get_int_int(conf, CONF_ssh_cipherlist, i)) {
11216 rekeying = "cipher settings changed";
11217 rekey_mandatory = TRUE;
11219 if (conf_get_int(ssh->conf, CONF_ssh2_des_cbc) !=
11220 conf_get_int(conf, CONF_ssh2_des_cbc)) {
11221 rekeying = "cipher settings changed";
11222 rekey_mandatory = TRUE;
11225 conf_free(ssh->conf);
11226 ssh->conf = conf_copy(conf);
11227 ssh_cache_conf_values(ssh);
11229 if (!ssh->bare_connection && rekeying) {
11230 if (!ssh->kex_in_progress) {
11231 do_ssh2_transport(ssh, rekeying, -1, NULL);
11232 } else if (rekey_mandatory) {
11233 ssh->deferred_rekey_reason = rekeying;
11239 * Called to send data down the SSH connection.
11241 static int ssh_send(void *handle, const char *buf, int len)
11243 Ssh ssh = (Ssh) handle;
11245 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
11248 ssh->protocol(ssh, (const unsigned char *)buf, len, 0);
11250 return ssh_sendbuffer(ssh);
11254 * Called to query the current amount of buffered stdin data.
11256 static int ssh_sendbuffer(void *handle)
11258 Ssh ssh = (Ssh) handle;
11259 int override_value;
11261 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
11265 * If the SSH socket itself has backed up, add the total backup
11266 * size on that to any individual buffer on the stdin channel.
11268 override_value = 0;
11269 if (ssh->throttled_all)
11270 override_value = ssh->overall_bufsize;
11272 if (ssh->version == 1) {
11273 return override_value;
11274 } else if (ssh->version == 2) {
11275 if (!ssh->mainchan)
11276 return override_value;
11278 return (override_value +
11279 bufchain_size(&ssh->mainchan->v.v2.outbuffer));
11286 * Called to set the size of the window from SSH's POV.
11288 static void ssh_size(void *handle, int width, int height)
11290 Ssh ssh = (Ssh) handle;
11291 struct Packet *pktout;
11293 ssh->term_width = width;
11294 ssh->term_height = height;
11296 switch (ssh->state) {
11297 case SSH_STATE_BEFORE_SIZE:
11298 case SSH_STATE_PREPACKET:
11299 case SSH_STATE_CLOSED:
11300 break; /* do nothing */
11301 case SSH_STATE_INTERMED:
11302 ssh->size_needed = TRUE; /* buffer for later */
11304 case SSH_STATE_SESSION:
11305 if (!conf_get_int(ssh->conf, CONF_nopty)) {
11306 if (ssh->version == 1) {
11307 send_packet(ssh, SSH1_CMSG_WINDOW_SIZE,
11308 PKT_INT, ssh->term_height,
11309 PKT_INT, ssh->term_width,
11310 PKT_INT, 0, PKT_INT, 0, PKT_END);
11311 } else if (ssh->mainchan) {
11312 pktout = ssh2_chanreq_init(ssh->mainchan, "window-change",
11314 ssh2_pkt_adduint32(pktout, ssh->term_width);
11315 ssh2_pkt_adduint32(pktout, ssh->term_height);
11316 ssh2_pkt_adduint32(pktout, 0);
11317 ssh2_pkt_adduint32(pktout, 0);
11318 ssh2_pkt_send(ssh, pktout);
11326 * Return a list of the special codes that make sense in this
11329 static const struct telnet_special *ssh_get_specials(void *handle)
11331 static const struct telnet_special ssh1_ignore_special[] = {
11332 {"IGNORE message", TS_NOP}
11334 static const struct telnet_special ssh2_ignore_special[] = {
11335 {"IGNORE message", TS_NOP},
11337 static const struct telnet_special ssh2_rekey_special[] = {
11338 {"Repeat key exchange", TS_REKEY},
11340 static const struct telnet_special ssh2_session_specials[] = {
11343 /* These are the signal names defined by RFC 4254.
11344 * They include all the ISO C signals, but are a subset of the POSIX
11345 * required signals. */
11346 {"SIGINT (Interrupt)", TS_SIGINT},
11347 {"SIGTERM (Terminate)", TS_SIGTERM},
11348 {"SIGKILL (Kill)", TS_SIGKILL},
11349 {"SIGQUIT (Quit)", TS_SIGQUIT},
11350 {"SIGHUP (Hangup)", TS_SIGHUP},
11351 {"More signals", TS_SUBMENU},
11352 {"SIGABRT", TS_SIGABRT}, {"SIGALRM", TS_SIGALRM},
11353 {"SIGFPE", TS_SIGFPE}, {"SIGILL", TS_SIGILL},
11354 {"SIGPIPE", TS_SIGPIPE}, {"SIGSEGV", TS_SIGSEGV},
11355 {"SIGUSR1", TS_SIGUSR1}, {"SIGUSR2", TS_SIGUSR2},
11356 {NULL, TS_EXITMENU}
11358 static const struct telnet_special specials_end[] = {
11359 {NULL, TS_EXITMENU}
11361 /* XXX review this length for any changes: */
11362 static struct telnet_special ssh_specials[lenof(ssh2_ignore_special) +
11363 lenof(ssh2_rekey_special) +
11364 lenof(ssh2_session_specials) +
11365 lenof(specials_end)];
11366 Ssh ssh = (Ssh) handle;
11368 #define ADD_SPECIALS(name) \
11370 assert((i + lenof(name)) <= lenof(ssh_specials)); \
11371 memcpy(&ssh_specials[i], name, sizeof name); \
11372 i += lenof(name); \
11375 if (ssh->version == 1) {
11376 /* Don't bother offering IGNORE if we've decided the remote
11377 * won't cope with it, since we wouldn't bother sending it if
11379 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE))
11380 ADD_SPECIALS(ssh1_ignore_special);
11381 } else if (ssh->version == 2) {
11382 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH2_IGNORE))
11383 ADD_SPECIALS(ssh2_ignore_special);
11384 if (!(ssh->remote_bugs & BUG_SSH2_REKEY) && !ssh->bare_connection)
11385 ADD_SPECIALS(ssh2_rekey_special);
11387 ADD_SPECIALS(ssh2_session_specials);
11388 } /* else we're not ready yet */
11391 ADD_SPECIALS(specials_end);
11392 return ssh_specials;
11396 #undef ADD_SPECIALS
11400 * Send special codes. TS_EOF is useful for `plink', so you
11401 * can send an EOF and collect resulting output (e.g. `plink
11404 static void ssh_special(void *handle, Telnet_Special code)
11406 Ssh ssh = (Ssh) handle;
11407 struct Packet *pktout;
11409 if (code == TS_EOF) {
11410 if (ssh->state != SSH_STATE_SESSION) {
11412 * Buffer the EOF in case we are pre-SESSION, so we can
11413 * send it as soon as we reach SESSION.
11415 if (code == TS_EOF)
11416 ssh->eof_needed = TRUE;
11419 if (ssh->version == 1) {
11420 send_packet(ssh, SSH1_CMSG_EOF, PKT_END);
11421 } else if (ssh->mainchan) {
11422 sshfwd_write_eof(ssh->mainchan);
11423 ssh->send_ok = 0; /* now stop trying to read from stdin */
11425 logevent("Sent EOF message");
11426 } else if (code == TS_PING || code == TS_NOP) {
11427 if (ssh->state == SSH_STATE_CLOSED
11428 || ssh->state == SSH_STATE_PREPACKET) return;
11429 if (ssh->version == 1) {
11430 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE))
11431 send_packet(ssh, SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
11433 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH2_IGNORE)) {
11434 pktout = ssh2_pkt_init(SSH2_MSG_IGNORE);
11435 ssh2_pkt_addstring_start(pktout);
11436 ssh2_pkt_send_noqueue(ssh, pktout);
11439 } else if (code == TS_REKEY) {
11440 if (!ssh->kex_in_progress && !ssh->bare_connection &&
11441 ssh->version == 2) {
11442 do_ssh2_transport(ssh, "at user request", -1, NULL);
11444 } else if (code == TS_BRK) {
11445 if (ssh->state == SSH_STATE_CLOSED
11446 || ssh->state == SSH_STATE_PREPACKET) return;
11447 if (ssh->version == 1) {
11448 logevent("Unable to send BREAK signal in SSH-1");
11449 } else if (ssh->mainchan) {
11450 pktout = ssh2_chanreq_init(ssh->mainchan, "break", NULL, NULL);
11451 ssh2_pkt_adduint32(pktout, 0); /* default break length */
11452 ssh2_pkt_send(ssh, pktout);
11455 /* Is is a POSIX signal? */
11456 const char *signame = NULL;
11457 if (code == TS_SIGABRT) signame = "ABRT";
11458 if (code == TS_SIGALRM) signame = "ALRM";
11459 if (code == TS_SIGFPE) signame = "FPE";
11460 if (code == TS_SIGHUP) signame = "HUP";
11461 if (code == TS_SIGILL) signame = "ILL";
11462 if (code == TS_SIGINT) signame = "INT";
11463 if (code == TS_SIGKILL) signame = "KILL";
11464 if (code == TS_SIGPIPE) signame = "PIPE";
11465 if (code == TS_SIGQUIT) signame = "QUIT";
11466 if (code == TS_SIGSEGV) signame = "SEGV";
11467 if (code == TS_SIGTERM) signame = "TERM";
11468 if (code == TS_SIGUSR1) signame = "USR1";
11469 if (code == TS_SIGUSR2) signame = "USR2";
11470 /* The SSH-2 protocol does in principle support arbitrary named
11471 * signals, including signame@domain, but we don't support those. */
11473 /* It's a signal. */
11474 if (ssh->version == 2 && ssh->mainchan) {
11475 pktout = ssh2_chanreq_init(ssh->mainchan, "signal", NULL, NULL);
11476 ssh2_pkt_addstring(pktout, signame);
11477 ssh2_pkt_send(ssh, pktout);
11478 logeventf(ssh, "Sent signal SIG%s", signame);
11481 /* Never heard of it. Do nothing */
11486 void *new_sock_channel(void *handle, struct PortForwarding *pf)
11488 Ssh ssh = (Ssh) handle;
11489 struct ssh_channel *c;
11490 c = snew(struct ssh_channel);
11493 ssh2_channel_init(c);
11494 c->halfopen = TRUE;
11495 c->type = CHAN_SOCKDATA_DORMANT;/* identify channel type */
11497 add234(ssh->channels, c);
11501 unsigned ssh_alloc_sharing_channel(Ssh ssh, void *sharing_ctx)
11503 struct ssh_channel *c;
11504 c = snew(struct ssh_channel);
11507 ssh2_channel_init(c);
11508 c->type = CHAN_SHARING;
11509 c->u.sharing.ctx = sharing_ctx;
11510 add234(ssh->channels, c);
11514 void ssh_delete_sharing_channel(Ssh ssh, unsigned localid)
11516 struct ssh_channel *c;
11518 c = find234(ssh->channels, &localid, ssh_channelfind);
11520 ssh_channel_destroy(c);
11523 void ssh_send_packet_from_downstream(Ssh ssh, unsigned id, int type,
11524 const void *data, int datalen,
11525 const char *additional_log_text)
11527 struct Packet *pkt;
11529 pkt = ssh2_pkt_init(type);
11530 pkt->downstream_id = id;
11531 pkt->additional_log_text = additional_log_text;
11532 ssh2_pkt_adddata(pkt, data, datalen);
11533 ssh2_pkt_send(ssh, pkt);
11537 * This is called when stdout/stderr (the entity to which
11538 * from_backend sends data) manages to clear some backlog.
11540 static void ssh_unthrottle(void *handle, int bufsize)
11542 Ssh ssh = (Ssh) handle;
11545 if (ssh->version == 1) {
11546 if (ssh->v1_stdout_throttling && bufsize < SSH1_BUFFER_LIMIT) {
11547 ssh->v1_stdout_throttling = 0;
11548 ssh_throttle_conn(ssh, -1);
11551 if (ssh->mainchan) {
11552 ssh2_set_window(ssh->mainchan,
11553 bufsize < ssh->mainchan->v.v2.locmaxwin ?
11554 ssh->mainchan->v.v2.locmaxwin - bufsize : 0);
11555 if (ssh_is_simple(ssh))
11558 buflimit = ssh->mainchan->v.v2.locmaxwin;
11559 if (ssh->mainchan->throttling_conn && bufsize <= buflimit) {
11560 ssh->mainchan->throttling_conn = 0;
11561 ssh_throttle_conn(ssh, -1);
11567 * Now process any SSH connection data that was stashed in our
11568 * queue while we were frozen.
11570 ssh_process_queued_incoming_data(ssh);
11573 void ssh_send_port_open(void *channel, const char *hostname, int port,
11576 struct ssh_channel *c = (struct ssh_channel *)channel;
11578 struct Packet *pktout;
11580 logeventf(ssh, "Opening connection to %s:%d for %s", hostname, port, org);
11582 if (ssh->version == 1) {
11583 send_packet(ssh, SSH1_MSG_PORT_OPEN,
11584 PKT_INT, c->localid,
11587 /* PKT_STR, <org:orgport>, */
11590 pktout = ssh2_chanopen_init(c, "direct-tcpip");
11592 char *trimmed_host = host_strduptrim(hostname);
11593 ssh2_pkt_addstring(pktout, trimmed_host);
11594 sfree(trimmed_host);
11596 ssh2_pkt_adduint32(pktout, port);
11598 * We make up values for the originator data; partly it's
11599 * too much hassle to keep track, and partly I'm not
11600 * convinced the server should be told details like that
11601 * about my local network configuration.
11602 * The "originator IP address" is syntactically a numeric
11603 * IP address, and some servers (e.g., Tectia) get upset
11604 * if it doesn't match this syntax.
11606 ssh2_pkt_addstring(pktout, "0.0.0.0");
11607 ssh2_pkt_adduint32(pktout, 0);
11608 ssh2_pkt_send(ssh, pktout);
11612 static int ssh_connected(void *handle)
11614 Ssh ssh = (Ssh) handle;
11615 return ssh->s != NULL;
11618 static int ssh_sendok(void *handle)
11620 Ssh ssh = (Ssh) handle;
11621 return ssh->send_ok;
11624 static int ssh_ldisc(void *handle, int option)
11626 Ssh ssh = (Ssh) handle;
11627 if (option == LD_ECHO)
11628 return ssh->echoing;
11629 if (option == LD_EDIT)
11630 return ssh->editing;
11634 static void ssh_provide_ldisc(void *handle, void *ldisc)
11636 Ssh ssh = (Ssh) handle;
11637 ssh->ldisc = ldisc;
11640 static void ssh_provide_logctx(void *handle, void *logctx)
11642 Ssh ssh = (Ssh) handle;
11643 ssh->logctx = logctx;
11646 static int ssh_return_exitcode(void *handle)
11648 Ssh ssh = (Ssh) handle;
11649 if (ssh->s != NULL)
11652 return (ssh->exitcode >= 0 ? ssh->exitcode : INT_MAX);
11656 * cfg_info for SSH is the protocol running in this session.
11657 * (1 or 2 for the full SSH-1 or SSH-2 protocol; -1 for the bare
11658 * SSH-2 connection protocol, i.e. a downstream; 0 for not-decided-yet.)
11660 static int ssh_cfg_info(void *handle)
11662 Ssh ssh = (Ssh) handle;
11663 if (ssh->version == 0)
11664 return 0; /* don't know yet */
11665 else if (ssh->bare_connection)
11668 return ssh->version;
11672 * Gross hack: pscp will try to start SFTP but fall back to scp1 if
11673 * that fails. This variable is the means by which scp.c can reach
11674 * into the SSH code and find out which one it got.
11676 extern int ssh_fallback_cmd(void *handle)
11678 Ssh ssh = (Ssh) handle;
11679 return ssh->fallback_cmd;
11682 Backend ssh_backend = {
11692 ssh_return_exitcode,
11696 ssh_provide_logctx,
11699 ssh_test_for_upstream,