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 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 char *ssh2_pkt_type(Pkt_KCtx pkt_kctx, Pkt_ACtx pkt_actx, int type)
239 translatea(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE,SSH2_PKTCTX_GSSAPI);
240 translatea(SSH2_MSG_USERAUTH_GSSAPI_TOKEN,SSH2_PKTCTX_GSSAPI);
241 translatea(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE,SSH2_PKTCTX_GSSAPI);
242 translatea(SSH2_MSG_USERAUTH_GSSAPI_ERROR,SSH2_PKTCTX_GSSAPI);
243 translatea(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK,SSH2_PKTCTX_GSSAPI);
244 translatea(SSH2_MSG_USERAUTH_GSSAPI_MIC, SSH2_PKTCTX_GSSAPI);
245 translate(SSH2_MSG_DISCONNECT);
246 translate(SSH2_MSG_IGNORE);
247 translate(SSH2_MSG_UNIMPLEMENTED);
248 translate(SSH2_MSG_DEBUG);
249 translate(SSH2_MSG_SERVICE_REQUEST);
250 translate(SSH2_MSG_SERVICE_ACCEPT);
251 translate(SSH2_MSG_KEXINIT);
252 translate(SSH2_MSG_NEWKEYS);
253 translatek(SSH2_MSG_KEXDH_INIT, SSH2_PKTCTX_DHGROUP);
254 translatek(SSH2_MSG_KEXDH_REPLY, SSH2_PKTCTX_DHGROUP);
255 translatek(SSH2_MSG_KEX_DH_GEX_REQUEST_OLD, SSH2_PKTCTX_DHGEX);
256 translatek(SSH2_MSG_KEX_DH_GEX_REQUEST, SSH2_PKTCTX_DHGEX);
257 translatek(SSH2_MSG_KEX_DH_GEX_GROUP, SSH2_PKTCTX_DHGEX);
258 translatek(SSH2_MSG_KEX_DH_GEX_INIT, SSH2_PKTCTX_DHGEX);
259 translatek(SSH2_MSG_KEX_DH_GEX_REPLY, SSH2_PKTCTX_DHGEX);
260 translatek(SSH2_MSG_KEXRSA_PUBKEY, SSH2_PKTCTX_RSAKEX);
261 translatek(SSH2_MSG_KEXRSA_SECRET, SSH2_PKTCTX_RSAKEX);
262 translatek(SSH2_MSG_KEXRSA_DONE, SSH2_PKTCTX_RSAKEX);
263 translatek(SSH2_MSG_KEX_ECDH_INIT, SSH2_PKTCTX_ECDHKEX);
264 translatek(SSH2_MSG_KEX_ECDH_REPLY, SSH2_PKTCTX_ECDHKEX);
265 translate(SSH2_MSG_USERAUTH_REQUEST);
266 translate(SSH2_MSG_USERAUTH_FAILURE);
267 translate(SSH2_MSG_USERAUTH_SUCCESS);
268 translate(SSH2_MSG_USERAUTH_BANNER);
269 translatea(SSH2_MSG_USERAUTH_PK_OK, SSH2_PKTCTX_PUBLICKEY);
270 translatea(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, SSH2_PKTCTX_PASSWORD);
271 translatea(SSH2_MSG_USERAUTH_INFO_REQUEST, SSH2_PKTCTX_KBDINTER);
272 translatea(SSH2_MSG_USERAUTH_INFO_RESPONSE, SSH2_PKTCTX_KBDINTER);
273 translate(SSH2_MSG_GLOBAL_REQUEST);
274 translate(SSH2_MSG_REQUEST_SUCCESS);
275 translate(SSH2_MSG_REQUEST_FAILURE);
276 translate(SSH2_MSG_CHANNEL_OPEN);
277 translate(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
278 translate(SSH2_MSG_CHANNEL_OPEN_FAILURE);
279 translate(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
280 translate(SSH2_MSG_CHANNEL_DATA);
281 translate(SSH2_MSG_CHANNEL_EXTENDED_DATA);
282 translate(SSH2_MSG_CHANNEL_EOF);
283 translate(SSH2_MSG_CHANNEL_CLOSE);
284 translate(SSH2_MSG_CHANNEL_REQUEST);
285 translate(SSH2_MSG_CHANNEL_SUCCESS);
286 translate(SSH2_MSG_CHANNEL_FAILURE);
292 /* Enumeration values for fields in SSH-1 packets */
294 PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR, PKT_BIGNUM,
298 * Coroutine mechanics for the sillier bits of the code. If these
299 * macros look impenetrable to you, you might find it helpful to
302 * http://www.chiark.greenend.org.uk/~sgtatham/coroutines.html
304 * which explains the theory behind these macros.
306 * In particular, if you are getting `case expression not constant'
307 * errors when building with MS Visual Studio, this is because MS's
308 * Edit and Continue debugging feature causes their compiler to
309 * violate ANSI C. To disable Edit and Continue debugging:
311 * - right-click ssh.c in the FileView
313 * - select the C/C++ tab and the General category
314 * - under `Debug info:', select anything _other_ than `Program
315 * Database for Edit and Continue'.
317 #define crBegin(v) { int *crLine = &v; switch(v) { case 0:;
318 #define crBeginState crBegin(s->crLine)
319 #define crStateP(t, v) \
321 if (!(v)) { s = (v) = snew(struct t); s->crLine = 0; } \
323 #define crState(t) crStateP(t, ssh->t)
324 #define crFinish(z) } *crLine = 0; return (z); }
325 #define crFinishV } *crLine = 0; return; }
326 #define crFinishFree(z) } sfree(s); return (z); }
327 #define crFinishFreeV } sfree(s); return; }
328 #define crReturn(z) \
330 *crLine =__LINE__; return (z); case __LINE__:;\
334 *crLine=__LINE__; return; case __LINE__:;\
336 #define crStop(z) do{ *crLine = 0; return (z); }while(0)
337 #define crStopV do{ *crLine = 0; return; }while(0)
338 #define crWaitUntil(c) do { crReturn(0); } while (!(c))
339 #define crWaitUntilV(c) do { crReturnV; } while (!(c))
343 static struct Packet *ssh1_pkt_init(int pkt_type);
344 static struct Packet *ssh2_pkt_init(int pkt_type);
345 static void ssh_pkt_ensure(struct Packet *, int length);
346 static void ssh_pkt_adddata(struct Packet *, const void *data, int len);
347 static void ssh_pkt_addbyte(struct Packet *, unsigned char value);
348 static void ssh2_pkt_addbool(struct Packet *, unsigned char value);
349 static void ssh_pkt_adduint32(struct Packet *, unsigned long value);
350 static void ssh_pkt_addstring_start(struct Packet *);
351 static void ssh_pkt_addstring_str(struct Packet *, const char *data);
352 static void ssh_pkt_addstring_data(struct Packet *, const char *data, int len);
353 static void ssh_pkt_addstring(struct Packet *, const char *data);
354 static unsigned char *ssh2_mpint_fmt(Bignum b, int *len);
355 static void ssh1_pkt_addmp(struct Packet *, Bignum b);
356 static void ssh2_pkt_addmp(struct Packet *, Bignum b);
357 static int ssh2_pkt_construct(Ssh, struct Packet *);
358 static void ssh2_pkt_send(Ssh, struct Packet *);
359 static void ssh2_pkt_send_noqueue(Ssh, struct Packet *);
360 static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen,
361 struct Packet *pktin);
362 static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
363 struct Packet *pktin);
364 static void ssh2_channel_check_close(struct ssh_channel *c);
365 static void ssh_channel_destroy(struct ssh_channel *c);
368 * Buffer management constants. There are several of these for
369 * various different purposes:
371 * - SSH1_BUFFER_LIMIT is the amount of backlog that must build up
372 * on a local data stream before we throttle the whole SSH
373 * connection (in SSH-1 only). Throttling the whole connection is
374 * pretty drastic so we set this high in the hope it won't
377 * - SSH_MAX_BACKLOG is the amount of backlog that must build up
378 * on the SSH connection itself before we defensively throttle
379 * _all_ local data streams. This is pretty drastic too (though
380 * thankfully unlikely in SSH-2 since the window mechanism should
381 * ensure that the server never has any need to throttle its end
382 * of the connection), so we set this high as well.
384 * - OUR_V2_WINSIZE is the maximum window size we present on SSH-2
387 * - OUR_V2_BIGWIN is the window size we advertise for the only
388 * channel in a simple connection. It must be <= INT_MAX.
390 * - OUR_V2_MAXPKT is the official "maximum packet size" we send
391 * to the remote side. This actually has nothing to do with the
392 * size of the _packet_, but is instead a limit on the amount
393 * of data we're willing to receive in a single SSH2 channel
396 * - OUR_V2_PACKETLIMIT is actually the maximum size of SSH
397 * _packet_ we're prepared to cope with. It must be a multiple
398 * of the cipher block size, and must be at least 35000.
401 #define SSH1_BUFFER_LIMIT 32768
402 #define SSH_MAX_BACKLOG 32768
403 #define OUR_V2_WINSIZE 16384
404 #define OUR_V2_BIGWIN 0x7fffffff
405 #define OUR_V2_MAXPKT 0x4000UL
406 #define OUR_V2_PACKETLIMIT 0x9000UL
408 const static struct ssh_signkey *hostkey_algs[] = {
409 &ssh_ecdsa_nistp256, &ssh_ecdsa_nistp384, &ssh_ecdsa_nistp521,
413 const static struct ssh_mac *macs[] = {
414 &ssh_hmac_sha256, &ssh_hmac_sha1, &ssh_hmac_sha1_96, &ssh_hmac_md5
416 const static struct ssh_mac *buggymacs[] = {
417 &ssh_hmac_sha1_buggy, &ssh_hmac_sha1_96_buggy, &ssh_hmac_md5
420 static void *ssh_comp_none_init(void)
424 static void ssh_comp_none_cleanup(void *handle)
427 static int ssh_comp_none_block(void *handle, unsigned char *block, int len,
428 unsigned char **outblock, int *outlen)
432 static int ssh_comp_none_disable(void *handle)
436 const static struct ssh_compress ssh_comp_none = {
438 ssh_comp_none_init, ssh_comp_none_cleanup, ssh_comp_none_block,
439 ssh_comp_none_init, ssh_comp_none_cleanup, ssh_comp_none_block,
440 ssh_comp_none_disable, NULL
442 extern const struct ssh_compress ssh_zlib;
443 const static struct ssh_compress *compressions[] = {
444 &ssh_zlib, &ssh_comp_none
447 enum { /* channel types */
452 CHAN_SOCKDATA_DORMANT, /* one the remote hasn't confirmed */
454 * CHAN_SHARING indicates a channel which is tracked here on
455 * behalf of a connection-sharing downstream. We do almost nothing
456 * with these channels ourselves: all messages relating to them
457 * get thrown straight to sshshare.c and passed on almost
458 * unmodified to downstream.
462 * CHAN_ZOMBIE is used to indicate a channel for which we've
463 * already destroyed the local data source: for instance, if a
464 * forwarded port experiences a socket error on the local side, we
465 * immediately destroy its local socket and turn the SSH channel
471 typedef void (*handler_fn_t)(Ssh ssh, struct Packet *pktin);
472 typedef void (*chandler_fn_t)(Ssh ssh, struct Packet *pktin, void *ctx);
473 typedef void (*cchandler_fn_t)(struct ssh_channel *, struct Packet *, void *);
476 * Each channel has a queue of outstanding CHANNEL_REQUESTS and their
479 struct outstanding_channel_request {
480 cchandler_fn_t handler;
482 struct outstanding_channel_request *next;
486 * 2-3-4 tree storing channels.
489 Ssh ssh; /* pointer back to main context */
490 unsigned remoteid, localid;
492 /* True if we opened this channel but server hasn't confirmed. */
495 * In SSH-1, this value contains four bits:
497 * 1 We have sent SSH1_MSG_CHANNEL_CLOSE.
498 * 2 We have sent SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION.
499 * 4 We have received SSH1_MSG_CHANNEL_CLOSE.
500 * 8 We have received SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION.
502 * A channel is completely finished with when all four bits are set.
504 * In SSH-2, the four bits mean:
506 * 1 We have sent SSH2_MSG_CHANNEL_EOF.
507 * 2 We have sent SSH2_MSG_CHANNEL_CLOSE.
508 * 4 We have received SSH2_MSG_CHANNEL_EOF.
509 * 8 We have received SSH2_MSG_CHANNEL_CLOSE.
511 * A channel is completely finished with when we have both sent
512 * and received CLOSE.
514 * The symbolic constants below use the SSH-2 terminology, which
515 * is a bit confusing in SSH-1, but we have to use _something_.
517 #define CLOSES_SENT_EOF 1
518 #define CLOSES_SENT_CLOSE 2
519 #define CLOSES_RCVD_EOF 4
520 #define CLOSES_RCVD_CLOSE 8
524 * This flag indicates that an EOF is pending on the outgoing side
525 * of the channel: that is, wherever we're getting the data for
526 * this channel has sent us some data followed by EOF. We can't
527 * actually send the EOF until we've finished sending the data, so
528 * we set this flag instead to remind us to do so once our buffer
534 * True if this channel is causing the underlying connection to be
539 struct ssh2_data_channel {
541 unsigned remwindow, remmaxpkt;
542 /* locwindow is signed so we can cope with excess data. */
543 int locwindow, locmaxwin;
545 * remlocwin is the amount of local window that we think
546 * the remote end had available to it after it sent the
547 * last data packet or window adjust ack.
551 * These store the list of channel requests that haven't
554 struct outstanding_channel_request *chanreq_head, *chanreq_tail;
555 enum { THROTTLED, UNTHROTTLING, UNTHROTTLED } throttle_state;
559 struct ssh_agent_channel {
560 unsigned char *message;
561 unsigned char msglen[4];
562 unsigned lensofar, totallen;
563 int outstanding_requests;
565 struct ssh_x11_channel {
566 struct X11Connection *xconn;
569 struct ssh_pfd_channel {
570 struct PortForwarding *pf;
572 struct ssh_sharing_channel {
579 * 2-3-4 tree storing remote->local port forwardings. SSH-1 and SSH-2
580 * use this structure in different ways, reflecting SSH-2's
581 * altogether saner approach to port forwarding.
583 * In SSH-1, you arrange a remote forwarding by sending the server
584 * the remote port number, and the local destination host:port.
585 * When a connection comes in, the server sends you back that
586 * host:port pair, and you connect to it. This is a ready-made
587 * security hole if you're not on the ball: a malicious server
588 * could send you back _any_ host:port pair, so if you trustingly
589 * connect to the address it gives you then you've just opened the
590 * entire inside of your corporate network just by connecting
591 * through it to a dodgy SSH server. Hence, we must store a list of
592 * host:port pairs we _are_ trying to forward to, and reject a
593 * connection request from the server if it's not in the list.
595 * In SSH-2, each side of the connection minds its own business and
596 * doesn't send unnecessary information to the other. You arrange a
597 * remote forwarding by sending the server just the remote port
598 * number. When a connection comes in, the server tells you which
599 * of its ports was connected to; and _you_ have to remember what
600 * local host:port pair went with that port number.
602 * Hence, in SSH-1 this structure is indexed by destination
603 * host:port pair, whereas in SSH-2 it is indexed by source port.
605 struct ssh_portfwd; /* forward declaration */
607 struct ssh_rportfwd {
608 unsigned sport, dport;
612 struct ssh_portfwd *pfrec;
615 static void free_rportfwd(struct ssh_rportfwd *pf)
618 sfree(pf->sportdesc);
626 * Separately to the rportfwd tree (which is for looking up port
627 * open requests from the server), a tree of _these_ structures is
628 * used to keep track of all the currently open port forwardings,
629 * so that we can reconfigure in mid-session if the user requests
633 enum { DESTROY, KEEP, CREATE } status;
635 unsigned sport, dport;
638 struct ssh_rportfwd *remote;
640 struct PortListener *local;
642 #define free_portfwd(pf) ( \
643 ((pf) ? (sfree((pf)->saddr), sfree((pf)->daddr), \
644 sfree((pf)->sserv), sfree((pf)->dserv)) : (void)0 ), sfree(pf) )
647 long length; /* length of packet: see below */
648 long forcepad; /* SSH-2: force padding to at least this length */
649 int type; /* only used for incoming packets */
650 unsigned long sequence; /* SSH-2 incoming sequence number */
651 unsigned char *data; /* allocated storage */
652 unsigned char *body; /* offset of payload within `data' */
653 long savedpos; /* dual-purpose saved packet position: see below */
654 long maxlen; /* amount of storage allocated for `data' */
655 long encrypted_len; /* for SSH-2 total-size counting */
658 * A note on the 'length' and 'savedpos' fields above.
660 * Incoming packets are set up so that pkt->length is measured
661 * relative to pkt->body, which itself points to a few bytes after
662 * pkt->data (skipping some uninteresting header fields including
663 * the packet type code). The ssh_pkt_get* functions all expect
664 * this setup, and they also use pkt->savedpos to indicate how far
665 * through the packet being decoded they've got - and that, too,
666 * is an offset from pkt->body rather than pkt->data.
668 * During construction of an outgoing packet, however, pkt->length
669 * is measured relative to the base pointer pkt->data, and
670 * pkt->body is not really used for anything until the packet is
671 * ready for sending. In this mode, pkt->savedpos is reused as a
672 * temporary variable by the addstring functions, which write out
673 * a string length field and then keep going back and updating it
674 * as more data is appended to the subsequent string data field;
675 * pkt->savedpos stores the offset (again relative to pkt->data)
676 * of the start of the string data field.
679 /* Extra metadata used in SSH packet logging mode, allowing us to
680 * log in the packet header line that the packet came from a
681 * connection-sharing downstream and what if anything unusual was
682 * done to it. The additional_log_text field is expected to be a
683 * static string - it will not be freed. */
684 unsigned downstream_id;
685 const char *additional_log_text;
688 static void ssh1_protocol(Ssh ssh, void *vin, int inlen,
689 struct Packet *pktin);
690 static void ssh2_protocol(Ssh ssh, void *vin, int inlen,
691 struct Packet *pktin);
692 static void ssh2_bare_connection_protocol(Ssh ssh, void *vin, int inlen,
693 struct Packet *pktin);
694 static void ssh1_protocol_setup(Ssh ssh);
695 static void ssh2_protocol_setup(Ssh ssh);
696 static void ssh2_bare_connection_protocol_setup(Ssh ssh);
697 static void ssh_size(void *handle, int width, int height);
698 static void ssh_special(void *handle, Telnet_Special);
699 static int ssh2_try_send(struct ssh_channel *c);
700 static void ssh2_add_channel_data(struct ssh_channel *c, char *buf, int len);
701 static void ssh_throttle_all(Ssh ssh, int enable, int bufsize);
702 static void ssh2_set_window(struct ssh_channel *c, int newwin);
703 static int ssh_sendbuffer(void *handle);
704 static int ssh_do_close(Ssh ssh, int notify_exit);
705 static unsigned long ssh_pkt_getuint32(struct Packet *pkt);
706 static int ssh2_pkt_getbool(struct Packet *pkt);
707 static void ssh_pkt_getstring(struct Packet *pkt, char **p, int *length);
708 static void ssh2_timer(void *ctx, unsigned long now);
709 static void do_ssh2_transport(Ssh ssh, void *vin, int inlen,
710 struct Packet *pktin);
711 static void ssh2_msg_unexpected(Ssh ssh, struct Packet *pktin);
713 struct rdpkt1_state_tag {
714 long len, pad, biglen, to_read;
715 unsigned long realcrc, gotcrc;
719 struct Packet *pktin;
722 struct rdpkt2_state_tag {
723 long len, pad, payload, packetlen, maclen;
726 unsigned long incoming_sequence;
727 struct Packet *pktin;
730 struct rdpkt2_bare_state_tag {
734 unsigned long incoming_sequence;
735 struct Packet *pktin;
738 struct queued_handler;
739 struct queued_handler {
741 chandler_fn_t handler;
743 struct queued_handler *next;
747 const struct plug_function_table *fn;
748 /* the above field _must_ be first in the structure */
758 unsigned char session_key[32];
760 int v1_remote_protoflags;
761 int v1_local_protoflags;
762 int agentfwd_enabled;
765 const struct ssh_cipher *cipher;
768 const struct ssh2_cipher *cscipher, *sccipher;
769 void *cs_cipher_ctx, *sc_cipher_ctx;
770 const struct ssh_mac *csmac, *scmac;
771 int csmac_etm, scmac_etm;
772 void *cs_mac_ctx, *sc_mac_ctx;
773 const struct ssh_compress *cscomp, *sccomp;
774 void *cs_comp_ctx, *sc_comp_ctx;
775 const struct ssh_kex *kex;
776 const struct ssh_signkey *hostkey;
777 char *hostkey_str; /* string representation, for easy checking in rekeys */
778 unsigned char v2_session_id[SSH2_KEX_MAX_HASH_LEN];
779 int v2_session_id_len;
783 int attempting_connshare;
789 int echoing, editing;
793 int ospeed, ispeed; /* temporaries */
794 int term_width, term_height;
796 tree234 *channels; /* indexed by local id */
797 struct ssh_channel *mainchan; /* primary session channel */
798 int ncmode; /* is primary channel direct-tcpip? */
803 tree234 *rportfwds, *portfwds;
807 SSH_STATE_BEFORE_SIZE,
813 int size_needed, eof_needed;
814 int sent_console_eof;
815 int got_pty; /* affects EOF behaviour on main channel */
817 struct Packet **queue;
818 int queuelen, queuesize;
820 unsigned char *deferred_send_data;
821 int deferred_len, deferred_size;
824 * Gross hack: pscp will try to start SFTP but fall back to
825 * scp1 if that fails. This variable is the means by which
826 * scp.c can reach into the SSH code and find out which one it
831 bufchain banner; /* accumulates banners during do_ssh2_authconn */
836 struct X11Display *x11disp;
837 struct X11FakeAuth *x11auth;
838 tree234 *x11authtree;
841 int conn_throttle_count;
844 int v1_stdout_throttling;
845 unsigned long v2_outgoing_sequence;
847 int ssh1_rdpkt_crstate;
848 int ssh2_rdpkt_crstate;
849 int ssh2_bare_rdpkt_crstate;
850 int ssh_gotdata_crstate;
851 int do_ssh1_connection_crstate;
853 void *do_ssh_init_state;
854 void *do_ssh1_login_state;
855 void *do_ssh2_transport_state;
856 void *do_ssh2_authconn_state;
857 void *do_ssh_connection_init_state;
859 struct rdpkt1_state_tag rdpkt1_state;
860 struct rdpkt2_state_tag rdpkt2_state;
861 struct rdpkt2_bare_state_tag rdpkt2_bare_state;
863 /* SSH-1 and SSH-2 use this for different things, but both use it */
864 int protocol_initial_phase_done;
866 void (*protocol) (Ssh ssh, void *vin, int inlen,
868 struct Packet *(*s_rdpkt) (Ssh ssh, unsigned char **data, int *datalen);
869 int (*do_ssh_init)(Ssh ssh, unsigned char c);
872 * We maintain our own copy of a Conf structure here. That way,
873 * when we're passed a new one for reconfiguration, we can check
874 * the differences and potentially reconfigure port forwardings
875 * etc in mid-session.
880 * Values cached out of conf so as to avoid the tree234 lookup
881 * cost every time they're used.
886 * Dynamically allocated username string created during SSH
887 * login. Stored in here rather than in the coroutine state so
888 * that it'll be reliably freed if we shut down the SSH session
889 * at some unexpected moment.
894 * Used to transfer data back from async callbacks.
896 void *agent_response;
897 int agent_response_len;
901 * The SSH connection can be set as `frozen', meaning we are
902 * not currently accepting incoming data from the network. This
903 * is slightly more serious than setting the _socket_ as
904 * frozen, because we may already have had data passed to us
905 * from the network which we need to delay processing until
906 * after the freeze is lifted, so we also need a bufchain to
910 bufchain queued_incoming_data;
913 * Dispatch table for packet types that we may have to deal
916 handler_fn_t packet_dispatch[256];
919 * Queues of one-off handler functions for success/failure
920 * indications from a request.
922 struct queued_handler *qhead, *qtail;
923 handler_fn_t q_saved_handler1, q_saved_handler2;
926 * This module deals with sending keepalives.
931 * Track incoming and outgoing data sizes and time, for
934 unsigned long incoming_data_size, outgoing_data_size, deferred_data_size;
935 unsigned long max_data_size;
937 unsigned long next_rekey, last_rekey;
938 char *deferred_rekey_reason; /* points to STATIC string; don't free */
941 * Fully qualified host name, which we need if doing GSSAPI.
947 * GSSAPI libraries for this session.
949 struct ssh_gss_liblist *gsslibs;
953 #define logevent(s) logevent(ssh->frontend, s)
955 /* logevent, only printf-formatted. */
956 static void logeventf(Ssh ssh, const char *fmt, ...)
962 buf = dupvprintf(fmt, ap);
968 static void bomb_out(Ssh ssh, char *text)
970 ssh_do_close(ssh, FALSE);
972 connection_fatal(ssh->frontend, "%s", text);
976 #define bombout(msg) bomb_out(ssh, dupprintf msg)
978 /* Helper function for common bits of parsing ttymodes. */
979 static void parse_ttymodes(Ssh ssh,
980 void (*do_mode)(void *data, char *mode, char *val),
985 for (val = conf_get_str_strs(ssh->conf, CONF_ttymodes, NULL, &key);
987 val = conf_get_str_strs(ssh->conf, CONF_ttymodes, key, &key)) {
989 * val[0] is either 'V', indicating that an explicit value
990 * follows it, or 'A' indicating that we should pass the
991 * value through from the local environment via get_ttymode.
994 val = get_ttymode(ssh->frontend, key);
996 do_mode(data, key, val);
1000 do_mode(data, key, val + 1); /* skip the 'V' */
1004 static int ssh_channelcmp(void *av, void *bv)
1006 struct ssh_channel *a = (struct ssh_channel *) av;
1007 struct ssh_channel *b = (struct ssh_channel *) bv;
1008 if (a->localid < b->localid)
1010 if (a->localid > b->localid)
1014 static int ssh_channelfind(void *av, void *bv)
1016 unsigned *a = (unsigned *) av;
1017 struct ssh_channel *b = (struct ssh_channel *) bv;
1018 if (*a < b->localid)
1020 if (*a > b->localid)
1025 static int ssh_rportcmp_ssh1(void *av, void *bv)
1027 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
1028 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
1030 if ( (i = strcmp(a->dhost, b->dhost)) != 0)
1031 return i < 0 ? -1 : +1;
1032 if (a->dport > b->dport)
1034 if (a->dport < b->dport)
1039 static int ssh_rportcmp_ssh2(void *av, void *bv)
1041 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
1042 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
1044 if ( (i = strcmp(a->shost, b->shost)) != 0)
1045 return i < 0 ? -1 : +1;
1046 if (a->sport > b->sport)
1048 if (a->sport < b->sport)
1054 * Special form of strcmp which can cope with NULL inputs. NULL is
1055 * defined to sort before even the empty string.
1057 static int nullstrcmp(const char *a, const char *b)
1059 if (a == NULL && b == NULL)
1065 return strcmp(a, b);
1068 static int ssh_portcmp(void *av, void *bv)
1070 struct ssh_portfwd *a = (struct ssh_portfwd *) av;
1071 struct ssh_portfwd *b = (struct ssh_portfwd *) bv;
1073 if (a->type > b->type)
1075 if (a->type < b->type)
1077 if (a->addressfamily > b->addressfamily)
1079 if (a->addressfamily < b->addressfamily)
1081 if ( (i = nullstrcmp(a->saddr, b->saddr)) != 0)
1082 return i < 0 ? -1 : +1;
1083 if (a->sport > b->sport)
1085 if (a->sport < b->sport)
1087 if (a->type != 'D') {
1088 if ( (i = nullstrcmp(a->daddr, b->daddr)) != 0)
1089 return i < 0 ? -1 : +1;
1090 if (a->dport > b->dport)
1092 if (a->dport < b->dport)
1098 static int alloc_channel_id(Ssh ssh)
1100 const unsigned CHANNEL_NUMBER_OFFSET = 256;
1101 unsigned low, high, mid;
1103 struct ssh_channel *c;
1106 * First-fit allocation of channel numbers: always pick the
1107 * lowest unused one. To do this, binary-search using the
1108 * counted B-tree to find the largest channel ID which is in a
1109 * contiguous sequence from the beginning. (Precisely
1110 * everything in that sequence must have ID equal to its tree
1111 * index plus CHANNEL_NUMBER_OFFSET.)
1113 tsize = count234(ssh->channels);
1117 while (high - low > 1) {
1118 mid = (high + low) / 2;
1119 c = index234(ssh->channels, mid);
1120 if (c->localid == mid + CHANNEL_NUMBER_OFFSET)
1121 low = mid; /* this one is fine */
1123 high = mid; /* this one is past it */
1126 * Now low points to either -1, or the tree index of the
1127 * largest ID in the initial sequence.
1130 unsigned i = low + 1 + CHANNEL_NUMBER_OFFSET;
1131 assert(NULL == find234(ssh->channels, &i, ssh_channelfind));
1133 return low + 1 + CHANNEL_NUMBER_OFFSET;
1136 static void c_write_stderr(int trusted, const char *buf, int len)
1139 for (i = 0; i < len; i++)
1140 if (buf[i] != '\r' && (trusted || buf[i] == '\n' || (buf[i] & 0x60)))
1141 fputc(buf[i], stderr);
1144 static void c_write(Ssh ssh, const char *buf, int len)
1146 if (flags & FLAG_STDERR)
1147 c_write_stderr(1, buf, len);
1149 from_backend(ssh->frontend, 1, buf, len);
1152 static void c_write_untrusted(Ssh ssh, const char *buf, int len)
1154 if (flags & FLAG_STDERR)
1155 c_write_stderr(0, buf, len);
1157 from_backend_untrusted(ssh->frontend, buf, len);
1160 static void c_write_str(Ssh ssh, const char *buf)
1162 c_write(ssh, buf, strlen(buf));
1165 static void ssh_free_packet(struct Packet *pkt)
1170 static struct Packet *ssh_new_packet(void)
1172 struct Packet *pkt = snew(struct Packet);
1174 pkt->body = pkt->data = NULL;
1180 static void ssh1_log_incoming_packet(Ssh ssh, struct Packet *pkt)
1183 struct logblank_t blanks[4];
1189 if (ssh->logomitdata &&
1190 (pkt->type == SSH1_SMSG_STDOUT_DATA ||
1191 pkt->type == SSH1_SMSG_STDERR_DATA ||
1192 pkt->type == SSH1_MSG_CHANNEL_DATA)) {
1193 /* "Session data" packets - omit the data string. */
1194 if (pkt->type == SSH1_MSG_CHANNEL_DATA)
1195 ssh_pkt_getuint32(pkt); /* skip channel id */
1196 blanks[nblanks].offset = pkt->savedpos + 4;
1197 blanks[nblanks].type = PKTLOG_OMIT;
1198 ssh_pkt_getstring(pkt, &str, &slen);
1200 blanks[nblanks].len = slen;
1204 log_packet(ssh->logctx, PKT_INCOMING, pkt->type,
1205 ssh1_pkt_type(pkt->type),
1206 pkt->body, pkt->length, nblanks, blanks, NULL,
1210 static void ssh1_log_outgoing_packet(Ssh ssh, struct Packet *pkt)
1213 struct logblank_t blanks[4];
1218 * For outgoing packets, pkt->length represents the length of the
1219 * whole packet starting at pkt->data (including some header), and
1220 * pkt->body refers to the point within that where the log-worthy
1221 * payload begins. However, incoming packets expect pkt->length to
1222 * represent only the payload length (that is, it's measured from
1223 * pkt->body not from pkt->data). Temporarily adjust our outgoing
1224 * packet to conform to the incoming-packet semantics, so that we
1225 * can analyse it with the ssh_pkt_get functions.
1227 pkt->length -= (pkt->body - pkt->data);
1230 if (ssh->logomitdata &&
1231 (pkt->type == SSH1_CMSG_STDIN_DATA ||
1232 pkt->type == SSH1_MSG_CHANNEL_DATA)) {
1233 /* "Session data" packets - omit the data string. */
1234 if (pkt->type == SSH1_MSG_CHANNEL_DATA)
1235 ssh_pkt_getuint32(pkt); /* skip channel id */
1236 blanks[nblanks].offset = pkt->savedpos + 4;
1237 blanks[nblanks].type = PKTLOG_OMIT;
1238 ssh_pkt_getstring(pkt, &str, &slen);
1240 blanks[nblanks].len = slen;
1245 if ((pkt->type == SSH1_CMSG_AUTH_PASSWORD ||
1246 pkt->type == SSH1_CMSG_AUTH_TIS_RESPONSE ||
1247 pkt->type == SSH1_CMSG_AUTH_CCARD_RESPONSE) &&
1248 conf_get_int(ssh->conf, CONF_logomitpass)) {
1249 /* If this is a password or similar packet, blank the password(s). */
1250 blanks[nblanks].offset = 0;
1251 blanks[nblanks].len = pkt->length;
1252 blanks[nblanks].type = PKTLOG_BLANK;
1254 } else if (pkt->type == SSH1_CMSG_X11_REQUEST_FORWARDING &&
1255 conf_get_int(ssh->conf, CONF_logomitpass)) {
1257 * If this is an X forwarding request packet, blank the fake
1260 * Note that while we blank the X authentication data here, we
1261 * don't take any special action to blank the start of an X11
1262 * channel, so using MIT-MAGIC-COOKIE-1 and actually opening
1263 * an X connection without having session blanking enabled is
1264 * likely to leak your cookie into the log.
1267 ssh_pkt_getstring(pkt, &str, &slen);
1268 blanks[nblanks].offset = pkt->savedpos;
1269 blanks[nblanks].type = PKTLOG_BLANK;
1270 ssh_pkt_getstring(pkt, &str, &slen);
1272 blanks[nblanks].len = pkt->savedpos - blanks[nblanks].offset;
1277 log_packet(ssh->logctx, PKT_OUTGOING, pkt->data[12],
1278 ssh1_pkt_type(pkt->data[12]),
1279 pkt->body, pkt->length,
1280 nblanks, blanks, NULL, 0, NULL);
1283 * Undo the above adjustment of pkt->length, to put the packet
1284 * back in the state we found it.
1286 pkt->length += (pkt->body - pkt->data);
1290 * Collect incoming data in the incoming packet buffer.
1291 * Decipher and verify the packet when it is completely read.
1292 * Drop SSH1_MSG_DEBUG and SSH1_MSG_IGNORE packets.
1293 * Update the *data and *datalen variables.
1294 * Return a Packet structure when a packet is completed.
1296 static struct Packet *ssh1_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
1298 struct rdpkt1_state_tag *st = &ssh->rdpkt1_state;
1300 crBegin(ssh->ssh1_rdpkt_crstate);
1302 st->pktin = ssh_new_packet();
1304 st->pktin->type = 0;
1305 st->pktin->length = 0;
1307 for (st->i = st->len = 0; st->i < 4; st->i++) {
1308 while ((*datalen) == 0)
1310 st->len = (st->len << 8) + **data;
1311 (*data)++, (*datalen)--;
1314 st->pad = 8 - (st->len % 8);
1315 st->biglen = st->len + st->pad;
1316 st->pktin->length = st->len - 5;
1318 if (st->biglen < 0) {
1319 bombout(("Extremely large packet length from server suggests"
1320 " data stream corruption"));
1321 ssh_free_packet(st->pktin);
1325 st->pktin->maxlen = st->biglen;
1326 st->pktin->data = snewn(st->biglen + APIEXTRA, unsigned char);
1328 st->to_read = st->biglen;
1329 st->p = st->pktin->data;
1330 while (st->to_read > 0) {
1331 st->chunk = st->to_read;
1332 while ((*datalen) == 0)
1334 if (st->chunk > (*datalen))
1335 st->chunk = (*datalen);
1336 memcpy(st->p, *data, st->chunk);
1338 *datalen -= st->chunk;
1340 st->to_read -= st->chunk;
1343 if (ssh->cipher && detect_attack(ssh->crcda_ctx, st->pktin->data,
1344 st->biglen, NULL)) {
1345 bombout(("Network attack (CRC compensation) detected!"));
1346 ssh_free_packet(st->pktin);
1351 ssh->cipher->decrypt(ssh->v1_cipher_ctx, st->pktin->data, st->biglen);
1353 st->realcrc = crc32_compute(st->pktin->data, st->biglen - 4);
1354 st->gotcrc = GET_32BIT(st->pktin->data + st->biglen - 4);
1355 if (st->gotcrc != st->realcrc) {
1356 bombout(("Incorrect CRC received on packet"));
1357 ssh_free_packet(st->pktin);
1361 st->pktin->body = st->pktin->data + st->pad + 1;
1363 if (ssh->v1_compressing) {
1364 unsigned char *decompblk;
1366 if (!zlib_decompress_block(ssh->sc_comp_ctx,
1367 st->pktin->body - 1, st->pktin->length + 1,
1368 &decompblk, &decomplen)) {
1369 bombout(("Zlib decompression encountered invalid data"));
1370 ssh_free_packet(st->pktin);
1374 if (st->pktin->maxlen < st->pad + decomplen) {
1375 st->pktin->maxlen = st->pad + decomplen;
1376 st->pktin->data = sresize(st->pktin->data,
1377 st->pktin->maxlen + APIEXTRA,
1379 st->pktin->body = st->pktin->data + st->pad + 1;
1382 memcpy(st->pktin->body - 1, decompblk, decomplen);
1384 st->pktin->length = decomplen - 1;
1387 st->pktin->type = st->pktin->body[-1];
1390 * Now pktin->body and pktin->length identify the semantic content
1391 * of the packet, excluding the initial type byte.
1395 ssh1_log_incoming_packet(ssh, st->pktin);
1397 st->pktin->savedpos = 0;
1399 crFinish(st->pktin);
1402 static void ssh2_log_incoming_packet(Ssh ssh, struct Packet *pkt)
1405 struct logblank_t blanks[4];
1411 if (ssh->logomitdata &&
1412 (pkt->type == SSH2_MSG_CHANNEL_DATA ||
1413 pkt->type == SSH2_MSG_CHANNEL_EXTENDED_DATA)) {
1414 /* "Session data" packets - omit the data string. */
1415 ssh_pkt_getuint32(pkt); /* skip channel id */
1416 if (pkt->type == SSH2_MSG_CHANNEL_EXTENDED_DATA)
1417 ssh_pkt_getuint32(pkt); /* skip extended data type */
1418 blanks[nblanks].offset = pkt->savedpos + 4;
1419 blanks[nblanks].type = PKTLOG_OMIT;
1420 ssh_pkt_getstring(pkt, &str, &slen);
1422 blanks[nblanks].len = slen;
1427 log_packet(ssh->logctx, PKT_INCOMING, pkt->type,
1428 ssh2_pkt_type(ssh->pkt_kctx, ssh->pkt_actx, pkt->type),
1429 pkt->body, pkt->length, nblanks, blanks, &pkt->sequence,
1433 static void ssh2_log_outgoing_packet(Ssh ssh, struct Packet *pkt)
1436 struct logblank_t blanks[4];
1441 * For outgoing packets, pkt->length represents the length of the
1442 * whole packet starting at pkt->data (including some header), and
1443 * pkt->body refers to the point within that where the log-worthy
1444 * payload begins. However, incoming packets expect pkt->length to
1445 * represent only the payload length (that is, it's measured from
1446 * pkt->body not from pkt->data). Temporarily adjust our outgoing
1447 * packet to conform to the incoming-packet semantics, so that we
1448 * can analyse it with the ssh_pkt_get functions.
1450 pkt->length -= (pkt->body - pkt->data);
1453 if (ssh->logomitdata &&
1454 (pkt->type == SSH2_MSG_CHANNEL_DATA ||
1455 pkt->type == SSH2_MSG_CHANNEL_EXTENDED_DATA)) {
1456 /* "Session data" packets - omit the data string. */
1457 ssh_pkt_getuint32(pkt); /* skip channel id */
1458 if (pkt->type == SSH2_MSG_CHANNEL_EXTENDED_DATA)
1459 ssh_pkt_getuint32(pkt); /* skip extended data type */
1460 blanks[nblanks].offset = pkt->savedpos + 4;
1461 blanks[nblanks].type = PKTLOG_OMIT;
1462 ssh_pkt_getstring(pkt, &str, &slen);
1464 blanks[nblanks].len = slen;
1469 if (pkt->type == SSH2_MSG_USERAUTH_REQUEST &&
1470 conf_get_int(ssh->conf, CONF_logomitpass)) {
1471 /* If this is a password packet, blank the password(s). */
1473 ssh_pkt_getstring(pkt, &str, &slen);
1474 ssh_pkt_getstring(pkt, &str, &slen);
1475 ssh_pkt_getstring(pkt, &str, &slen);
1476 if (slen == 8 && !memcmp(str, "password", 8)) {
1477 ssh2_pkt_getbool(pkt);
1478 /* Blank the password field. */
1479 blanks[nblanks].offset = pkt->savedpos;
1480 blanks[nblanks].type = PKTLOG_BLANK;
1481 ssh_pkt_getstring(pkt, &str, &slen);
1483 blanks[nblanks].len = pkt->savedpos - blanks[nblanks].offset;
1485 /* If there's another password field beyond it (change of
1486 * password), blank that too. */
1487 ssh_pkt_getstring(pkt, &str, &slen);
1489 blanks[nblanks-1].len =
1490 pkt->savedpos - blanks[nblanks].offset;
1493 } else if (ssh->pkt_actx == SSH2_PKTCTX_KBDINTER &&
1494 pkt->type == SSH2_MSG_USERAUTH_INFO_RESPONSE &&
1495 conf_get_int(ssh->conf, CONF_logomitpass)) {
1496 /* If this is a keyboard-interactive response packet, blank
1499 ssh_pkt_getuint32(pkt);
1500 blanks[nblanks].offset = pkt->savedpos;
1501 blanks[nblanks].type = PKTLOG_BLANK;
1503 ssh_pkt_getstring(pkt, &str, &slen);
1507 blanks[nblanks].len = pkt->savedpos - blanks[nblanks].offset;
1509 } else if (pkt->type == SSH2_MSG_CHANNEL_REQUEST &&
1510 conf_get_int(ssh->conf, CONF_logomitpass)) {
1512 * If this is an X forwarding request packet, blank the fake
1515 * Note that while we blank the X authentication data here, we
1516 * don't take any special action to blank the start of an X11
1517 * channel, so using MIT-MAGIC-COOKIE-1 and actually opening
1518 * an X connection without having session blanking enabled is
1519 * likely to leak your cookie into the log.
1522 ssh_pkt_getuint32(pkt);
1523 ssh_pkt_getstring(pkt, &str, &slen);
1524 if (slen == 7 && !memcmp(str, "x11-req", 0)) {
1525 ssh2_pkt_getbool(pkt);
1526 ssh2_pkt_getbool(pkt);
1527 ssh_pkt_getstring(pkt, &str, &slen);
1528 blanks[nblanks].offset = pkt->savedpos;
1529 blanks[nblanks].type = PKTLOG_BLANK;
1530 ssh_pkt_getstring(pkt, &str, &slen);
1532 blanks[nblanks].len = pkt->savedpos - blanks[nblanks].offset;
1538 log_packet(ssh->logctx, PKT_OUTGOING, pkt->data[5],
1539 ssh2_pkt_type(ssh->pkt_kctx, ssh->pkt_actx, pkt->data[5]),
1540 pkt->body, pkt->length, nblanks, blanks,
1541 &ssh->v2_outgoing_sequence,
1542 pkt->downstream_id, pkt->additional_log_text);
1545 * Undo the above adjustment of pkt->length, to put the packet
1546 * back in the state we found it.
1548 pkt->length += (pkt->body - pkt->data);
1551 static struct Packet *ssh2_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
1553 struct rdpkt2_state_tag *st = &ssh->rdpkt2_state;
1555 crBegin(ssh->ssh2_rdpkt_crstate);
1557 st->pktin = ssh_new_packet();
1559 st->pktin->type = 0;
1560 st->pktin->length = 0;
1562 st->cipherblk = ssh->sccipher->blksize;
1565 if (st->cipherblk < 8)
1567 st->maclen = ssh->scmac ? ssh->scmac->len : 0;
1569 if (ssh->sccipher && (ssh->sccipher->flags & SSH_CIPHER_IS_CBC) &&
1570 ssh->scmac && !ssh->scmac_etm) {
1572 * When dealing with a CBC-mode cipher, we want to avoid the
1573 * possibility of an attacker's tweaking the ciphertext stream
1574 * so as to cause us to feed the same block to the block
1575 * cipher more than once and thus leak information
1576 * (VU#958563). The way we do this is not to take any
1577 * decisions on the basis of anything we've decrypted until
1578 * we've verified it with a MAC. That includes the packet
1579 * length, so we just read data and check the MAC repeatedly,
1580 * and when the MAC passes, see if the length we've got is
1583 * This defence is unnecessary in OpenSSH ETM mode, because
1584 * the whole point of ETM mode is that the attacker can't
1585 * tweak the ciphertext stream at all without the MAC
1586 * detecting it before we decrypt anything.
1589 /* May as well allocate the whole lot now. */
1590 st->pktin->data = snewn(OUR_V2_PACKETLIMIT + st->maclen + APIEXTRA,
1593 /* Read an amount corresponding to the MAC. */
1594 for (st->i = 0; st->i < st->maclen; st->i++) {
1595 while ((*datalen) == 0)
1597 st->pktin->data[st->i] = *(*data)++;
1603 unsigned char seq[4];
1604 ssh->scmac->start(ssh->sc_mac_ctx);
1605 PUT_32BIT(seq, st->incoming_sequence);
1606 ssh->scmac->bytes(ssh->sc_mac_ctx, seq, 4);
1609 for (;;) { /* Once around this loop per cipher block. */
1610 /* Read another cipher-block's worth, and tack it onto the end. */
1611 for (st->i = 0; st->i < st->cipherblk; st->i++) {
1612 while ((*datalen) == 0)
1614 st->pktin->data[st->packetlen+st->maclen+st->i] = *(*data)++;
1617 /* Decrypt one more block (a little further back in the stream). */
1618 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
1619 st->pktin->data + st->packetlen,
1621 /* Feed that block to the MAC. */
1622 ssh->scmac->bytes(ssh->sc_mac_ctx,
1623 st->pktin->data + st->packetlen, st->cipherblk);
1624 st->packetlen += st->cipherblk;
1625 /* See if that gives us a valid packet. */
1626 if (ssh->scmac->verresult(ssh->sc_mac_ctx,
1627 st->pktin->data + st->packetlen) &&
1628 ((st->len = toint(GET_32BIT(st->pktin->data))) ==
1631 if (st->packetlen >= OUR_V2_PACKETLIMIT) {
1632 bombout(("No valid incoming packet found"));
1633 ssh_free_packet(st->pktin);
1637 st->pktin->maxlen = st->packetlen + st->maclen;
1638 st->pktin->data = sresize(st->pktin->data,
1639 st->pktin->maxlen + APIEXTRA,
1641 } else if (ssh->scmac && ssh->scmac_etm) {
1642 st->pktin->data = snewn(4 + APIEXTRA, unsigned char);
1645 * OpenSSH encrypt-then-MAC mode: the packet length is
1648 for (st->i = st->len = 0; st->i < 4; st->i++) {
1649 while ((*datalen) == 0)
1651 st->pktin->data[st->i] = *(*data)++;
1654 st->len = toint(GET_32BIT(st->pktin->data));
1657 * _Completely_ silly lengths should be stomped on before they
1658 * do us any more damage.
1660 if (st->len < 0 || st->len > OUR_V2_PACKETLIMIT ||
1661 st->len % st->cipherblk != 0) {
1662 bombout(("Incoming packet length field was garbled"));
1663 ssh_free_packet(st->pktin);
1668 * So now we can work out the total packet length.
1670 st->packetlen = st->len + 4;
1673 * Allocate memory for the rest of the packet.
1675 st->pktin->maxlen = st->packetlen + st->maclen;
1676 st->pktin->data = sresize(st->pktin->data,
1677 st->pktin->maxlen + APIEXTRA,
1681 * Read the remainder of the packet.
1683 for (st->i = 4; st->i < st->packetlen + st->maclen; st->i++) {
1684 while ((*datalen) == 0)
1686 st->pktin->data[st->i] = *(*data)++;
1694 && !ssh->scmac->verify(ssh->sc_mac_ctx, st->pktin->data,
1695 st->len + 4, st->incoming_sequence)) {
1696 bombout(("Incorrect MAC received on packet"));
1697 ssh_free_packet(st->pktin);
1701 /* Decrypt everything between the length field and the MAC. */
1703 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
1704 st->pktin->data + 4,
1707 st->pktin->data = snewn(st->cipherblk + APIEXTRA, unsigned char);
1710 * Acquire and decrypt the first block of the packet. This will
1711 * contain the length and padding details.
1713 for (st->i = st->len = 0; st->i < st->cipherblk; st->i++) {
1714 while ((*datalen) == 0)
1716 st->pktin->data[st->i] = *(*data)++;
1721 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
1722 st->pktin->data, st->cipherblk);
1725 * Now get the length figure.
1727 st->len = toint(GET_32BIT(st->pktin->data));
1730 * _Completely_ silly lengths should be stomped on before they
1731 * do us any more damage.
1733 if (st->len < 0 || st->len > OUR_V2_PACKETLIMIT ||
1734 (st->len + 4) % st->cipherblk != 0) {
1735 bombout(("Incoming packet was garbled on decryption"));
1736 ssh_free_packet(st->pktin);
1741 * So now we can work out the total packet length.
1743 st->packetlen = st->len + 4;
1746 * Allocate memory for the rest of the packet.
1748 st->pktin->maxlen = st->packetlen + st->maclen;
1749 st->pktin->data = sresize(st->pktin->data,
1750 st->pktin->maxlen + APIEXTRA,
1754 * Read and decrypt the remainder of the packet.
1756 for (st->i = st->cipherblk; st->i < st->packetlen + st->maclen;
1758 while ((*datalen) == 0)
1760 st->pktin->data[st->i] = *(*data)++;
1763 /* Decrypt everything _except_ the MAC. */
1765 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
1766 st->pktin->data + st->cipherblk,
1767 st->packetlen - st->cipherblk);
1773 && !ssh->scmac->verify(ssh->sc_mac_ctx, st->pktin->data,
1774 st->len + 4, st->incoming_sequence)) {
1775 bombout(("Incorrect MAC received on packet"));
1776 ssh_free_packet(st->pktin);
1780 /* Get and sanity-check the amount of random padding. */
1781 st->pad = st->pktin->data[4];
1782 if (st->pad < 4 || st->len - st->pad < 1) {
1783 bombout(("Invalid padding length on received packet"));
1784 ssh_free_packet(st->pktin);
1788 * This enables us to deduce the payload length.
1790 st->payload = st->len - st->pad - 1;
1792 st->pktin->length = st->payload + 5;
1793 st->pktin->encrypted_len = st->packetlen;
1795 st->pktin->sequence = st->incoming_sequence++;
1797 st->pktin->length = st->packetlen - st->pad;
1798 assert(st->pktin->length >= 0);
1801 * Decompress packet payload.
1804 unsigned char *newpayload;
1807 ssh->sccomp->decompress(ssh->sc_comp_ctx,
1808 st->pktin->data + 5, st->pktin->length - 5,
1809 &newpayload, &newlen)) {
1810 if (st->pktin->maxlen < newlen + 5) {
1811 st->pktin->maxlen = newlen + 5;
1812 st->pktin->data = sresize(st->pktin->data,
1813 st->pktin->maxlen + APIEXTRA,
1816 st->pktin->length = 5 + newlen;
1817 memcpy(st->pktin->data + 5, newpayload, newlen);
1823 * pktin->body and pktin->length should identify the semantic
1824 * content of the packet, excluding the initial type byte.
1826 st->pktin->type = st->pktin->data[5];
1827 st->pktin->body = st->pktin->data + 6;
1828 st->pktin->length -= 6;
1829 assert(st->pktin->length >= 0); /* one last double-check */
1832 ssh2_log_incoming_packet(ssh, st->pktin);
1834 st->pktin->savedpos = 0;
1836 crFinish(st->pktin);
1839 static struct Packet *ssh2_bare_connection_rdpkt(Ssh ssh, unsigned char **data,
1842 struct rdpkt2_bare_state_tag *st = &ssh->rdpkt2_bare_state;
1844 crBegin(ssh->ssh2_bare_rdpkt_crstate);
1847 * Read the packet length field.
1849 for (st->i = 0; st->i < 4; st->i++) {
1850 while ((*datalen) == 0)
1852 st->length[st->i] = *(*data)++;
1856 st->packetlen = toint(GET_32BIT_MSB_FIRST(st->length));
1857 if (st->packetlen <= 0 || st->packetlen >= OUR_V2_PACKETLIMIT) {
1858 bombout(("Invalid packet length received"));
1862 st->pktin = ssh_new_packet();
1863 st->pktin->data = snewn(st->packetlen, unsigned char);
1865 st->pktin->encrypted_len = st->packetlen;
1867 st->pktin->sequence = st->incoming_sequence++;
1870 * Read the remainder of the packet.
1872 for (st->i = 0; st->i < st->packetlen; st->i++) {
1873 while ((*datalen) == 0)
1875 st->pktin->data[st->i] = *(*data)++;
1880 * pktin->body and pktin->length should identify the semantic
1881 * content of the packet, excluding the initial type byte.
1883 st->pktin->type = st->pktin->data[0];
1884 st->pktin->body = st->pktin->data + 1;
1885 st->pktin->length = st->packetlen - 1;
1888 * Log incoming packet, possibly omitting sensitive fields.
1891 ssh2_log_incoming_packet(ssh, st->pktin);
1893 st->pktin->savedpos = 0;
1895 crFinish(st->pktin);
1898 static int s_wrpkt_prepare(Ssh ssh, struct Packet *pkt, int *offset_p)
1900 int pad, biglen, i, pktoffs;
1904 * XXX various versions of SC (including 8.8.4) screw up the
1905 * register allocation in this function and use the same register
1906 * (D6) for len and as a temporary, with predictable results. The
1907 * following sledgehammer prevents this.
1914 ssh1_log_outgoing_packet(ssh, pkt);
1916 if (ssh->v1_compressing) {
1917 unsigned char *compblk;
1919 zlib_compress_block(ssh->cs_comp_ctx,
1920 pkt->data + 12, pkt->length - 12,
1921 &compblk, &complen);
1922 ssh_pkt_ensure(pkt, complen + 2); /* just in case it's got bigger */
1923 memcpy(pkt->data + 12, compblk, complen);
1925 pkt->length = complen + 12;
1928 ssh_pkt_ensure(pkt, pkt->length + 4); /* space for CRC */
1930 len = pkt->length - 4 - 8; /* len(type+data+CRC) */
1931 pad = 8 - (len % 8);
1933 biglen = len + pad; /* len(padding+type+data+CRC) */
1935 for (i = pktoffs; i < 4+8; i++)
1936 pkt->data[i] = random_byte();
1937 crc = crc32_compute(pkt->data + pktoffs + 4, biglen - 4); /* all ex len */
1938 PUT_32BIT(pkt->data + pktoffs + 4 + biglen - 4, crc);
1939 PUT_32BIT(pkt->data + pktoffs, len);
1942 ssh->cipher->encrypt(ssh->v1_cipher_ctx,
1943 pkt->data + pktoffs + 4, biglen);
1945 if (offset_p) *offset_p = pktoffs;
1946 return biglen + 4; /* len(length+padding+type+data+CRC) */
1949 static int s_write(Ssh ssh, void *data, int len)
1952 log_packet(ssh->logctx, PKT_OUTGOING, -1, NULL, data, len,
1953 0, NULL, NULL, 0, NULL);
1956 return sk_write(ssh->s, (char *)data, len);
1959 static void s_wrpkt(Ssh ssh, struct Packet *pkt)
1961 int len, backlog, offset;
1962 len = s_wrpkt_prepare(ssh, pkt, &offset);
1963 backlog = s_write(ssh, pkt->data + offset, len);
1964 if (backlog > SSH_MAX_BACKLOG)
1965 ssh_throttle_all(ssh, 1, backlog);
1966 ssh_free_packet(pkt);
1969 static void s_wrpkt_defer(Ssh ssh, struct Packet *pkt)
1972 len = s_wrpkt_prepare(ssh, pkt, &offset);
1973 if (ssh->deferred_len + len > ssh->deferred_size) {
1974 ssh->deferred_size = ssh->deferred_len + len + 128;
1975 ssh->deferred_send_data = sresize(ssh->deferred_send_data,
1979 memcpy(ssh->deferred_send_data + ssh->deferred_len,
1980 pkt->data + offset, len);
1981 ssh->deferred_len += len;
1982 ssh_free_packet(pkt);
1986 * Construct a SSH-1 packet with the specified contents.
1987 * (This all-at-once interface used to be the only one, but now SSH-1
1988 * packets can also be constructed incrementally.)
1990 static struct Packet *construct_packet(Ssh ssh, int pkttype, va_list ap)
1996 pkt = ssh1_pkt_init(pkttype);
1998 while ((argtype = va_arg(ap, int)) != PKT_END) {
1999 unsigned char *argp, argchar;
2001 unsigned long argint;
2004 /* Actual fields in the packet */
2006 argint = va_arg(ap, int);
2007 ssh_pkt_adduint32(pkt, argint);
2010 argchar = (unsigned char) va_arg(ap, int);
2011 ssh_pkt_addbyte(pkt, argchar);
2014 argp = va_arg(ap, unsigned char *);
2015 arglen = va_arg(ap, int);
2016 ssh_pkt_adddata(pkt, argp, arglen);
2019 sargp = va_arg(ap, char *);
2020 ssh_pkt_addstring(pkt, sargp);
2023 bn = va_arg(ap, Bignum);
2024 ssh1_pkt_addmp(pkt, bn);
2032 static void send_packet(Ssh ssh, int pkttype, ...)
2036 va_start(ap, pkttype);
2037 pkt = construct_packet(ssh, pkttype, ap);
2042 static void defer_packet(Ssh ssh, int pkttype, ...)
2046 va_start(ap, pkttype);
2047 pkt = construct_packet(ssh, pkttype, ap);
2049 s_wrpkt_defer(ssh, pkt);
2052 static int ssh_versioncmp(char *a, char *b)
2055 unsigned long av, bv;
2057 av = strtoul(a, &ae, 10);
2058 bv = strtoul(b, &be, 10);
2060 return (av < bv ? -1 : +1);
2065 av = strtoul(ae, &ae, 10);
2066 bv = strtoul(be, &be, 10);
2068 return (av < bv ? -1 : +1);
2073 * Utility routines for putting an SSH-protocol `string' and
2074 * `uint32' into a hash state.
2076 static void hash_string(const struct ssh_hash *h, void *s, void *str, int len)
2078 unsigned char lenblk[4];
2079 PUT_32BIT(lenblk, len);
2080 h->bytes(s, lenblk, 4);
2081 h->bytes(s, str, len);
2084 static void hash_uint32(const struct ssh_hash *h, void *s, unsigned i)
2086 unsigned char intblk[4];
2087 PUT_32BIT(intblk, i);
2088 h->bytes(s, intblk, 4);
2092 * Packet construction functions. Mostly shared between SSH-1 and SSH-2.
2094 static void ssh_pkt_ensure(struct Packet *pkt, int length)
2096 if (pkt->maxlen < length) {
2097 unsigned char *body = pkt->body;
2098 int offset = body ? body - pkt->data : 0;
2099 pkt->maxlen = length + 256;
2100 pkt->data = sresize(pkt->data, pkt->maxlen + APIEXTRA, unsigned char);
2101 if (body) pkt->body = pkt->data + offset;
2104 static void ssh_pkt_adddata(struct Packet *pkt, const void *data, int len)
2107 ssh_pkt_ensure(pkt, pkt->length);
2108 memcpy(pkt->data + pkt->length - len, data, len);
2110 static void ssh_pkt_addbyte(struct Packet *pkt, unsigned char byte)
2112 ssh_pkt_adddata(pkt, &byte, 1);
2114 static void ssh2_pkt_addbool(struct Packet *pkt, unsigned char value)
2116 ssh_pkt_adddata(pkt, &value, 1);
2118 static void ssh_pkt_adduint32(struct Packet *pkt, unsigned long value)
2121 PUT_32BIT(x, value);
2122 ssh_pkt_adddata(pkt, x, 4);
2124 static void ssh_pkt_addstring_start(struct Packet *pkt)
2126 ssh_pkt_adduint32(pkt, 0);
2127 pkt->savedpos = pkt->length;
2129 static void ssh_pkt_addstring_str(struct Packet *pkt, const char *data)
2131 ssh_pkt_adddata(pkt, data, strlen(data));
2132 PUT_32BIT(pkt->data + pkt->savedpos - 4, pkt->length - pkt->savedpos);
2134 static void ssh_pkt_addstring_data(struct Packet *pkt, const char *data,
2137 ssh_pkt_adddata(pkt, data, len);
2138 PUT_32BIT(pkt->data + pkt->savedpos - 4, pkt->length - pkt->savedpos);
2140 static void ssh_pkt_addstring(struct Packet *pkt, const char *data)
2142 ssh_pkt_addstring_start(pkt);
2143 ssh_pkt_addstring_str(pkt, data);
2145 static void ssh1_pkt_addmp(struct Packet *pkt, Bignum b)
2147 int len = ssh1_bignum_length(b);
2148 unsigned char *data = snewn(len, unsigned char);
2149 (void) ssh1_write_bignum(data, b);
2150 ssh_pkt_adddata(pkt, data, len);
2153 static unsigned char *ssh2_mpint_fmt(Bignum b, int *len)
2156 int i, n = (bignum_bitcount(b) + 7) / 8;
2157 p = snewn(n + 1, unsigned char);
2159 for (i = 1; i <= n; i++)
2160 p[i] = bignum_byte(b, n - i);
2162 while (i <= n && p[i] == 0 && (p[i + 1] & 0x80) == 0)
2164 memmove(p, p + i, n + 1 - i);
2168 static void ssh2_pkt_addmp(struct Packet *pkt, Bignum b)
2172 p = ssh2_mpint_fmt(b, &len);
2173 ssh_pkt_addstring_start(pkt);
2174 ssh_pkt_addstring_data(pkt, (char *)p, len);
2178 static struct Packet *ssh1_pkt_init(int pkt_type)
2180 struct Packet *pkt = ssh_new_packet();
2181 pkt->length = 4 + 8; /* space for length + max padding */
2182 ssh_pkt_addbyte(pkt, pkt_type);
2183 pkt->body = pkt->data + pkt->length;
2184 pkt->type = pkt_type;
2185 pkt->downstream_id = 0;
2186 pkt->additional_log_text = NULL;
2190 /* For legacy code (SSH-1 and -2 packet construction used to be separate) */
2191 #define ssh2_pkt_ensure(pkt, length) ssh_pkt_ensure(pkt, length)
2192 #define ssh2_pkt_adddata(pkt, data, len) ssh_pkt_adddata(pkt, data, len)
2193 #define ssh2_pkt_addbyte(pkt, byte) ssh_pkt_addbyte(pkt, byte)
2194 #define ssh2_pkt_adduint32(pkt, value) ssh_pkt_adduint32(pkt, value)
2195 #define ssh2_pkt_addstring_start(pkt) ssh_pkt_addstring_start(pkt)
2196 #define ssh2_pkt_addstring_str(pkt, data) ssh_pkt_addstring_str(pkt, data)
2197 #define ssh2_pkt_addstring_data(pkt, data, len) ssh_pkt_addstring_data(pkt, data, len)
2198 #define ssh2_pkt_addstring(pkt, data) ssh_pkt_addstring(pkt, data)
2200 static struct Packet *ssh2_pkt_init(int pkt_type)
2202 struct Packet *pkt = ssh_new_packet();
2203 pkt->length = 5; /* space for packet length + padding length */
2205 pkt->type = pkt_type;
2206 ssh_pkt_addbyte(pkt, (unsigned char) pkt_type);
2207 pkt->body = pkt->data + pkt->length; /* after packet type */
2208 pkt->downstream_id = 0;
2209 pkt->additional_log_text = NULL;
2214 * Construct an SSH-2 final-form packet: compress it, encrypt it,
2215 * put the MAC on it. Final packet, ready to be sent, is stored in
2216 * pkt->data. Total length is returned.
2218 static int ssh2_pkt_construct(Ssh ssh, struct Packet *pkt)
2220 int cipherblk, maclen, padding, unencrypted_prefix, i;
2223 ssh2_log_outgoing_packet(ssh, pkt);
2225 if (ssh->bare_connection) {
2227 * Trivial packet construction for the bare connection
2230 PUT_32BIT(pkt->data + 1, pkt->length - 5);
2231 pkt->body = pkt->data + 1;
2232 ssh->v2_outgoing_sequence++; /* only for diagnostics, really */
2233 return pkt->length - 1;
2237 * Compress packet payload.
2240 unsigned char *newpayload;
2243 ssh->cscomp->compress(ssh->cs_comp_ctx, pkt->data + 5,
2245 &newpayload, &newlen)) {
2247 ssh2_pkt_adddata(pkt, newpayload, newlen);
2253 * Add padding. At least four bytes, and must also bring total
2254 * length (minus MAC) up to a multiple of the block size.
2255 * If pkt->forcepad is set, make sure the packet is at least that size
2258 cipherblk = ssh->cscipher ? ssh->cscipher->blksize : 8; /* block size */
2259 cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */
2261 unencrypted_prefix = (ssh->csmac && ssh->csmac_etm) ? 4 : 0;
2262 if (pkt->length + padding < pkt->forcepad)
2263 padding = pkt->forcepad - pkt->length;
2265 (cipherblk - (pkt->length - unencrypted_prefix + padding) % cipherblk)
2267 assert(padding <= 255);
2268 maclen = ssh->csmac ? ssh->csmac->len : 0;
2269 ssh2_pkt_ensure(pkt, pkt->length + padding + maclen);
2270 pkt->data[4] = padding;
2271 for (i = 0; i < padding; i++)
2272 pkt->data[pkt->length + i] = random_byte();
2273 PUT_32BIT(pkt->data, pkt->length + padding - 4);
2274 if (ssh->csmac && ssh->csmac_etm) {
2276 * OpenSSH-defined encrypt-then-MAC protocol.
2279 ssh->cscipher->encrypt(ssh->cs_cipher_ctx,
2280 pkt->data + 4, pkt->length + padding - 4);
2281 ssh->csmac->generate(ssh->cs_mac_ctx, pkt->data,
2282 pkt->length + padding,
2283 ssh->v2_outgoing_sequence);
2286 * SSH-2 standard protocol.
2289 ssh->csmac->generate(ssh->cs_mac_ctx, pkt->data,
2290 pkt->length + padding,
2291 ssh->v2_outgoing_sequence);
2293 ssh->cscipher->encrypt(ssh->cs_cipher_ctx,
2294 pkt->data, pkt->length + padding);
2297 ssh->v2_outgoing_sequence++; /* whether or not we MACed */
2298 pkt->encrypted_len = pkt->length + padding;
2300 /* Ready-to-send packet starts at pkt->data. We return length. */
2301 pkt->body = pkt->data;
2302 return pkt->length + padding + maclen;
2306 * Routines called from the main SSH code to send packets. There
2307 * are quite a few of these, because we have two separate
2308 * mechanisms for delaying the sending of packets:
2310 * - In order to send an IGNORE message and a password message in
2311 * a single fixed-length blob, we require the ability to
2312 * concatenate the encrypted forms of those two packets _into_ a
2313 * single blob and then pass it to our <network.h> transport
2314 * layer in one go. Hence, there's a deferment mechanism which
2315 * works after packet encryption.
2317 * - In order to avoid sending any connection-layer messages
2318 * during repeat key exchange, we have to queue up any such
2319 * outgoing messages _before_ they are encrypted (and in
2320 * particular before they're allocated sequence numbers), and
2321 * then send them once we've finished.
2323 * I call these mechanisms `defer' and `queue' respectively, so as
2324 * to distinguish them reasonably easily.
2326 * The functions send_noqueue() and defer_noqueue() free the packet
2327 * structure they are passed. Every outgoing packet goes through
2328 * precisely one of these functions in its life; packets passed to
2329 * ssh2_pkt_send() or ssh2_pkt_defer() either go straight to one of
2330 * these or get queued, and then when the queue is later emptied
2331 * the packets are all passed to defer_noqueue().
2333 * When using a CBC-mode cipher, it's necessary to ensure that an
2334 * attacker can't provide data to be encrypted using an IV that they
2335 * know. We ensure this by prefixing each packet that might contain
2336 * user data with an SSH_MSG_IGNORE. This is done using the deferral
2337 * mechanism, so in this case send_noqueue() ends up redirecting to
2338 * defer_noqueue(). If you don't like this inefficiency, don't use
2342 static void ssh2_pkt_defer_noqueue(Ssh, struct Packet *, int);
2343 static void ssh_pkt_defersend(Ssh);
2346 * Send an SSH-2 packet immediately, without queuing or deferring.
2348 static void ssh2_pkt_send_noqueue(Ssh ssh, struct Packet *pkt)
2352 if (ssh->cscipher != NULL && (ssh->cscipher->flags & SSH_CIPHER_IS_CBC)) {
2353 /* We need to send two packets, so use the deferral mechanism. */
2354 ssh2_pkt_defer_noqueue(ssh, pkt, FALSE);
2355 ssh_pkt_defersend(ssh);
2358 len = ssh2_pkt_construct(ssh, pkt);
2359 backlog = s_write(ssh, pkt->body, len);
2360 if (backlog > SSH_MAX_BACKLOG)
2361 ssh_throttle_all(ssh, 1, backlog);
2363 ssh->outgoing_data_size += pkt->encrypted_len;
2364 if (!ssh->kex_in_progress &&
2365 !ssh->bare_connection &&
2366 ssh->max_data_size != 0 &&
2367 ssh->outgoing_data_size > ssh->max_data_size)
2368 do_ssh2_transport(ssh, "too much data sent", -1, NULL);
2370 ssh_free_packet(pkt);
2374 * Defer an SSH-2 packet.
2376 static void ssh2_pkt_defer_noqueue(Ssh ssh, struct Packet *pkt, int noignore)
2379 if (ssh->cscipher != NULL && (ssh->cscipher->flags & SSH_CIPHER_IS_CBC) &&
2380 ssh->deferred_len == 0 && !noignore &&
2381 !(ssh->remote_bugs & BUG_CHOKES_ON_SSH2_IGNORE)) {
2383 * Interpose an SSH_MSG_IGNORE to ensure that user data don't
2384 * get encrypted with a known IV.
2386 struct Packet *ipkt = ssh2_pkt_init(SSH2_MSG_IGNORE);
2387 ssh2_pkt_addstring_start(ipkt);
2388 ssh2_pkt_defer_noqueue(ssh, ipkt, TRUE);
2390 len = ssh2_pkt_construct(ssh, pkt);
2391 if (ssh->deferred_len + len > ssh->deferred_size) {
2392 ssh->deferred_size = ssh->deferred_len + len + 128;
2393 ssh->deferred_send_data = sresize(ssh->deferred_send_data,
2397 memcpy(ssh->deferred_send_data + ssh->deferred_len, pkt->body, len);
2398 ssh->deferred_len += len;
2399 ssh->deferred_data_size += pkt->encrypted_len;
2400 ssh_free_packet(pkt);
2404 * Queue an SSH-2 packet.
2406 static void ssh2_pkt_queue(Ssh ssh, struct Packet *pkt)
2408 assert(ssh->queueing);
2410 if (ssh->queuelen >= ssh->queuesize) {
2411 ssh->queuesize = ssh->queuelen + 32;
2412 ssh->queue = sresize(ssh->queue, ssh->queuesize, struct Packet *);
2415 ssh->queue[ssh->queuelen++] = pkt;
2419 * Either queue or send a packet, depending on whether queueing is
2422 static void ssh2_pkt_send(Ssh ssh, struct Packet *pkt)
2425 ssh2_pkt_queue(ssh, pkt);
2427 ssh2_pkt_send_noqueue(ssh, pkt);
2431 * Either queue or defer a packet, depending on whether queueing is
2434 static void ssh2_pkt_defer(Ssh ssh, struct Packet *pkt)
2437 ssh2_pkt_queue(ssh, pkt);
2439 ssh2_pkt_defer_noqueue(ssh, pkt, FALSE);
2443 * Send the whole deferred data block constructed by
2444 * ssh2_pkt_defer() or SSH-1's defer_packet().
2446 * The expected use of the defer mechanism is that you call
2447 * ssh2_pkt_defer() a few times, then call ssh_pkt_defersend(). If
2448 * not currently queueing, this simply sets up deferred_send_data
2449 * and then sends it. If we _are_ currently queueing, the calls to
2450 * ssh2_pkt_defer() put the deferred packets on to the queue
2451 * instead, and therefore ssh_pkt_defersend() has no deferred data
2452 * to send. Hence, there's no need to make it conditional on
2455 static void ssh_pkt_defersend(Ssh ssh)
2458 backlog = s_write(ssh, ssh->deferred_send_data, ssh->deferred_len);
2459 ssh->deferred_len = ssh->deferred_size = 0;
2460 sfree(ssh->deferred_send_data);
2461 ssh->deferred_send_data = NULL;
2462 if (backlog > SSH_MAX_BACKLOG)
2463 ssh_throttle_all(ssh, 1, backlog);
2465 ssh->outgoing_data_size += ssh->deferred_data_size;
2466 if (!ssh->kex_in_progress &&
2467 !ssh->bare_connection &&
2468 ssh->max_data_size != 0 &&
2469 ssh->outgoing_data_size > ssh->max_data_size)
2470 do_ssh2_transport(ssh, "too much data sent", -1, NULL);
2471 ssh->deferred_data_size = 0;
2475 * Send a packet whose length needs to be disguised (typically
2476 * passwords or keyboard-interactive responses).
2478 static void ssh2_pkt_send_with_padding(Ssh ssh, struct Packet *pkt,
2484 * The simplest way to do this is to adjust the
2485 * variable-length padding field in the outgoing packet.
2487 * Currently compiled out, because some Cisco SSH servers
2488 * don't like excessively padded packets (bah, why's it
2491 pkt->forcepad = padsize;
2492 ssh2_pkt_send(ssh, pkt);
2497 * If we can't do that, however, an alternative approach is
2498 * to use the pkt_defer mechanism to bundle the packet
2499 * tightly together with an SSH_MSG_IGNORE such that their
2500 * combined length is a constant. So first we construct the
2501 * final form of this packet and defer its sending.
2503 ssh2_pkt_defer(ssh, pkt);
2506 * Now construct an SSH_MSG_IGNORE which includes a string
2507 * that's an exact multiple of the cipher block size. (If
2508 * the cipher is NULL so that the block size is
2509 * unavailable, we don't do this trick at all, because we
2510 * gain nothing by it.)
2512 if (ssh->cscipher &&
2513 !(ssh->remote_bugs & BUG_CHOKES_ON_SSH2_IGNORE)) {
2516 stringlen = (256 - ssh->deferred_len);
2517 stringlen += ssh->cscipher->blksize - 1;
2518 stringlen -= (stringlen % ssh->cscipher->blksize);
2521 * Temporarily disable actual compression, so we
2522 * can guarantee to get this string exactly the
2523 * length we want it. The compression-disabling
2524 * routine should return an integer indicating how
2525 * many bytes we should adjust our string length
2529 ssh->cscomp->disable_compression(ssh->cs_comp_ctx);
2531 pkt = ssh2_pkt_init(SSH2_MSG_IGNORE);
2532 ssh2_pkt_addstring_start(pkt);
2533 for (i = 0; i < stringlen; i++) {
2534 char c = (char) random_byte();
2535 ssh2_pkt_addstring_data(pkt, &c, 1);
2537 ssh2_pkt_defer(ssh, pkt);
2539 ssh_pkt_defersend(ssh);
2544 * Send all queued SSH-2 packets. We send them by means of
2545 * ssh2_pkt_defer_noqueue(), in case they included a pair of
2546 * packets that needed to be lumped together.
2548 static void ssh2_pkt_queuesend(Ssh ssh)
2552 assert(!ssh->queueing);
2554 for (i = 0; i < ssh->queuelen; i++)
2555 ssh2_pkt_defer_noqueue(ssh, ssh->queue[i], FALSE);
2558 ssh_pkt_defersend(ssh);
2562 void bndebug(char *string, Bignum b)
2566 p = ssh2_mpint_fmt(b, &len);
2567 debug(("%s", string));
2568 for (i = 0; i < len; i++)
2569 debug((" %02x", p[i]));
2575 static void hash_mpint(const struct ssh_hash *h, void *s, Bignum b)
2579 p = ssh2_mpint_fmt(b, &len);
2580 hash_string(h, s, p, len);
2585 * Packet decode functions for both SSH-1 and SSH-2.
2587 static unsigned long ssh_pkt_getuint32(struct Packet *pkt)
2589 unsigned long value;
2590 if (pkt->length - pkt->savedpos < 4)
2591 return 0; /* arrgh, no way to decline (FIXME?) */
2592 value = GET_32BIT(pkt->body + pkt->savedpos);
2596 static int ssh2_pkt_getbool(struct Packet *pkt)
2598 unsigned long value;
2599 if (pkt->length - pkt->savedpos < 1)
2600 return 0; /* arrgh, no way to decline (FIXME?) */
2601 value = pkt->body[pkt->savedpos] != 0;
2605 static void ssh_pkt_getstring(struct Packet *pkt, char **p, int *length)
2610 if (pkt->length - pkt->savedpos < 4)
2612 len = toint(GET_32BIT(pkt->body + pkt->savedpos));
2617 if (pkt->length - pkt->savedpos < *length)
2619 *p = (char *)(pkt->body + pkt->savedpos);
2620 pkt->savedpos += *length;
2622 static void *ssh_pkt_getdata(struct Packet *pkt, int length)
2624 if (pkt->length - pkt->savedpos < length)
2626 pkt->savedpos += length;
2627 return pkt->body + (pkt->savedpos - length);
2629 static int ssh1_pkt_getrsakey(struct Packet *pkt, struct RSAKey *key,
2630 const unsigned char **keystr)
2634 j = makekey(pkt->body + pkt->savedpos,
2635 pkt->length - pkt->savedpos,
2642 assert(pkt->savedpos < pkt->length);
2646 static Bignum ssh1_pkt_getmp(struct Packet *pkt)
2651 j = ssh1_read_bignum(pkt->body + pkt->savedpos,
2652 pkt->length - pkt->savedpos, &b);
2660 static Bignum ssh2_pkt_getmp(struct Packet *pkt)
2666 ssh_pkt_getstring(pkt, &p, &length);
2671 b = bignum_from_bytes((unsigned char *)p, length);
2676 * Helper function to add an SSH-2 signature blob to a packet.
2677 * Expects to be shown the public key blob as well as the signature
2678 * blob. Normally works just like ssh2_pkt_addstring, but will
2679 * fiddle with the signature packet if necessary for
2680 * BUG_SSH2_RSA_PADDING.
2682 static void ssh2_add_sigblob(Ssh ssh, struct Packet *pkt,
2683 void *pkblob_v, int pkblob_len,
2684 void *sigblob_v, int sigblob_len)
2686 unsigned char *pkblob = (unsigned char *)pkblob_v;
2687 unsigned char *sigblob = (unsigned char *)sigblob_v;
2689 /* dmemdump(pkblob, pkblob_len); */
2690 /* dmemdump(sigblob, sigblob_len); */
2693 * See if this is in fact an ssh-rsa signature and a buggy
2694 * server; otherwise we can just do this the easy way.
2696 if ((ssh->remote_bugs & BUG_SSH2_RSA_PADDING) && pkblob_len > 4+7+4 &&
2697 (GET_32BIT(pkblob) == 7 && !memcmp(pkblob+4, "ssh-rsa", 7))) {
2698 int pos, len, siglen;
2701 * Find the byte length of the modulus.
2704 pos = 4+7; /* skip over "ssh-rsa" */
2705 len = toint(GET_32BIT(pkblob+pos)); /* get length of exponent */
2706 if (len < 0 || len > pkblob_len - pos - 4)
2708 pos += 4 + len; /* skip over exponent */
2709 if (pkblob_len - pos < 4)
2711 len = toint(GET_32BIT(pkblob+pos)); /* find length of modulus */
2712 if (len < 0 || len > pkblob_len - pos - 4)
2714 pos += 4; /* find modulus itself */
2715 while (len > 0 && pkblob[pos] == 0)
2717 /* debug(("modulus length is %d\n", len)); */
2720 * Now find the signature integer.
2722 pos = 4+7; /* skip over "ssh-rsa" */
2723 if (sigblob_len < pos+4)
2725 siglen = toint(GET_32BIT(sigblob+pos));
2726 if (siglen != sigblob_len - pos - 4)
2728 /* debug(("signature length is %d\n", siglen)); */
2730 if (len != siglen) {
2731 unsigned char newlen[4];
2732 ssh2_pkt_addstring_start(pkt);
2733 ssh2_pkt_addstring_data(pkt, (char *)sigblob, pos);
2734 /* dmemdump(sigblob, pos); */
2735 pos += 4; /* point to start of actual sig */
2736 PUT_32BIT(newlen, len);
2737 ssh2_pkt_addstring_data(pkt, (char *)newlen, 4);
2738 /* dmemdump(newlen, 4); */
2740 while (len-- > siglen) {
2741 ssh2_pkt_addstring_data(pkt, (char *)newlen, 1);
2742 /* dmemdump(newlen, 1); */
2744 ssh2_pkt_addstring_data(pkt, (char *)(sigblob+pos), siglen);
2745 /* dmemdump(sigblob+pos, siglen); */
2749 /* Otherwise fall through and do it the easy way. We also come
2750 * here as a fallback if we discover above that the key blob
2751 * is misformatted in some way. */
2755 ssh2_pkt_addstring_start(pkt);
2756 ssh2_pkt_addstring_data(pkt, (char *)sigblob, sigblob_len);
2760 * Examine the remote side's version string and compare it against
2761 * a list of known buggy implementations.
2763 static void ssh_detect_bugs(Ssh ssh, char *vstring)
2765 char *imp; /* pointer to implementation part */
2767 imp += strcspn(imp, "-");
2769 imp += strcspn(imp, "-");
2772 ssh->remote_bugs = 0;
2775 * General notes on server version strings:
2776 * - Not all servers reporting "Cisco-1.25" have all the bugs listed
2777 * here -- in particular, we've heard of one that's perfectly happy
2778 * with SSH1_MSG_IGNOREs -- but this string never seems to change,
2779 * so we can't distinguish them.
2781 if (conf_get_int(ssh->conf, CONF_sshbug_ignore1) == FORCE_ON ||
2782 (conf_get_int(ssh->conf, CONF_sshbug_ignore1) == AUTO &&
2783 (!strcmp(imp, "1.2.18") || !strcmp(imp, "1.2.19") ||
2784 !strcmp(imp, "1.2.20") || !strcmp(imp, "1.2.21") ||
2785 !strcmp(imp, "1.2.22") || !strcmp(imp, "Cisco-1.25") ||
2786 !strcmp(imp, "OSU_1.4alpha3") || !strcmp(imp, "OSU_1.5alpha4")))) {
2788 * These versions don't support SSH1_MSG_IGNORE, so we have
2789 * to use a different defence against password length
2792 ssh->remote_bugs |= BUG_CHOKES_ON_SSH1_IGNORE;
2793 logevent("We believe remote version has SSH-1 ignore bug");
2796 if (conf_get_int(ssh->conf, CONF_sshbug_plainpw1) == FORCE_ON ||
2797 (conf_get_int(ssh->conf, CONF_sshbug_plainpw1) == AUTO &&
2798 (!strcmp(imp, "Cisco-1.25") || !strcmp(imp, "OSU_1.4alpha3")))) {
2800 * These versions need a plain password sent; they can't
2801 * handle having a null and a random length of data after
2804 ssh->remote_bugs |= BUG_NEEDS_SSH1_PLAIN_PASSWORD;
2805 logevent("We believe remote version needs a plain SSH-1 password");
2808 if (conf_get_int(ssh->conf, CONF_sshbug_rsa1) == FORCE_ON ||
2809 (conf_get_int(ssh->conf, CONF_sshbug_rsa1) == AUTO &&
2810 (!strcmp(imp, "Cisco-1.25")))) {
2812 * These versions apparently have no clue whatever about
2813 * RSA authentication and will panic and die if they see
2814 * an AUTH_RSA message.
2816 ssh->remote_bugs |= BUG_CHOKES_ON_RSA;
2817 logevent("We believe remote version can't handle SSH-1 RSA authentication");
2820 if (conf_get_int(ssh->conf, CONF_sshbug_hmac2) == FORCE_ON ||
2821 (conf_get_int(ssh->conf, CONF_sshbug_hmac2) == AUTO &&
2822 !wc_match("* VShell", imp) &&
2823 (wc_match("2.1.0*", imp) || wc_match("2.0.*", imp) ||
2824 wc_match("2.2.0*", imp) || wc_match("2.3.0*", imp) ||
2825 wc_match("2.1 *", imp)))) {
2827 * These versions have the HMAC bug.
2829 ssh->remote_bugs |= BUG_SSH2_HMAC;
2830 logevent("We believe remote version has SSH-2 HMAC bug");
2833 if (conf_get_int(ssh->conf, CONF_sshbug_derivekey2) == FORCE_ON ||
2834 (conf_get_int(ssh->conf, CONF_sshbug_derivekey2) == AUTO &&
2835 !wc_match("* VShell", imp) &&
2836 (wc_match("2.0.0*", imp) || wc_match("2.0.10*", imp) ))) {
2838 * These versions have the key-derivation bug (failing to
2839 * include the literal shared secret in the hashes that
2840 * generate the keys).
2842 ssh->remote_bugs |= BUG_SSH2_DERIVEKEY;
2843 logevent("We believe remote version has SSH-2 key-derivation bug");
2846 if (conf_get_int(ssh->conf, CONF_sshbug_rsapad2) == FORCE_ON ||
2847 (conf_get_int(ssh->conf, CONF_sshbug_rsapad2) == AUTO &&
2848 (wc_match("OpenSSH_2.[5-9]*", imp) ||
2849 wc_match("OpenSSH_3.[0-2]*", imp) ||
2850 wc_match("mod_sftp/0.[0-8]*", imp) ||
2851 wc_match("mod_sftp/0.9.[0-8]", imp)))) {
2853 * These versions have the SSH-2 RSA padding bug.
2855 ssh->remote_bugs |= BUG_SSH2_RSA_PADDING;
2856 logevent("We believe remote version has SSH-2 RSA padding bug");
2859 if (conf_get_int(ssh->conf, CONF_sshbug_pksessid2) == FORCE_ON ||
2860 (conf_get_int(ssh->conf, CONF_sshbug_pksessid2) == AUTO &&
2861 wc_match("OpenSSH_2.[0-2]*", imp))) {
2863 * These versions have the SSH-2 session-ID bug in
2864 * public-key authentication.
2866 ssh->remote_bugs |= BUG_SSH2_PK_SESSIONID;
2867 logevent("We believe remote version has SSH-2 public-key-session-ID bug");
2870 if (conf_get_int(ssh->conf, CONF_sshbug_rekey2) == FORCE_ON ||
2871 (conf_get_int(ssh->conf, CONF_sshbug_rekey2) == AUTO &&
2872 (wc_match("DigiSSH_2.0", imp) ||
2873 wc_match("OpenSSH_2.[0-4]*", imp) ||
2874 wc_match("OpenSSH_2.5.[0-3]*", imp) ||
2875 wc_match("Sun_SSH_1.0", imp) ||
2876 wc_match("Sun_SSH_1.0.1", imp) ||
2877 /* All versions <= 1.2.6 (they changed their format in 1.2.7) */
2878 wc_match("WeOnlyDo-*", imp)))) {
2880 * These versions have the SSH-2 rekey bug.
2882 ssh->remote_bugs |= BUG_SSH2_REKEY;
2883 logevent("We believe remote version has SSH-2 rekey bug");
2886 if (conf_get_int(ssh->conf, CONF_sshbug_maxpkt2) == FORCE_ON ||
2887 (conf_get_int(ssh->conf, CONF_sshbug_maxpkt2) == AUTO &&
2888 (wc_match("1.36_sshlib GlobalSCAPE", imp) ||
2889 wc_match("1.36 sshlib: GlobalScape", imp)))) {
2891 * This version ignores our makpkt and needs to be throttled.
2893 ssh->remote_bugs |= BUG_SSH2_MAXPKT;
2894 logevent("We believe remote version ignores SSH-2 maximum packet size");
2897 if (conf_get_int(ssh->conf, CONF_sshbug_ignore2) == FORCE_ON) {
2899 * Servers that don't support SSH2_MSG_IGNORE. Currently,
2900 * none detected automatically.
2902 ssh->remote_bugs |= BUG_CHOKES_ON_SSH2_IGNORE;
2903 logevent("We believe remote version has SSH-2 ignore bug");
2906 if (conf_get_int(ssh->conf, CONF_sshbug_oldgex2) == FORCE_ON ||
2907 (conf_get_int(ssh->conf, CONF_sshbug_oldgex2) == AUTO &&
2908 (wc_match("OpenSSH_2.[235]*", imp)))) {
2910 * These versions only support the original (pre-RFC4419)
2911 * SSH-2 GEX request.
2913 ssh->remote_bugs |= BUG_SSH2_OLDGEX;
2914 logevent("We believe remote version has outdated SSH-2 GEX");
2917 if (conf_get_int(ssh->conf, CONF_sshbug_winadj) == FORCE_ON) {
2919 * Servers that don't support our winadj request for one
2920 * reason or another. Currently, none detected automatically.
2922 ssh->remote_bugs |= BUG_CHOKES_ON_WINADJ;
2923 logevent("We believe remote version has winadj bug");
2926 if (conf_get_int(ssh->conf, CONF_sshbug_chanreq) == FORCE_ON ||
2927 (conf_get_int(ssh->conf, CONF_sshbug_chanreq) == AUTO &&
2928 (wc_match("OpenSSH_[2-5].*", imp) ||
2929 wc_match("OpenSSH_6.[0-6]*", imp) ||
2930 wc_match("dropbear_0.[2-4][0-9]*", imp) ||
2931 wc_match("dropbear_0.5[01]*", imp)))) {
2933 * These versions have the SSH-2 channel request bug.
2934 * OpenSSH 6.7 and above do not:
2935 * https://bugzilla.mindrot.org/show_bug.cgi?id=1818
2936 * dropbear_0.52 and above do not:
2937 * https://secure.ucc.asn.au/hg/dropbear/rev/cd02449b709c
2939 ssh->remote_bugs |= BUG_SENDS_LATE_REQUEST_REPLY;
2940 logevent("We believe remote version has SSH-2 channel request bug");
2945 * The `software version' part of an SSH version string is required
2946 * to contain no spaces or minus signs.
2948 static void ssh_fix_verstring(char *str)
2950 /* Eat "<protoversion>-". */
2951 while (*str && *str != '-') str++;
2952 assert(*str == '-'); str++;
2954 /* Convert minus signs and spaces in the remaining string into
2957 if (*str == '-' || *str == ' ')
2964 * Send an appropriate SSH version string.
2966 static void ssh_send_verstring(Ssh ssh, const char *protoname, char *svers)
2970 if (ssh->version == 2) {
2972 * Construct a v2 version string.
2974 verstring = dupprintf("%s2.0-%s\015\012", protoname, sshver);
2977 * Construct a v1 version string.
2979 assert(!strcmp(protoname, "SSH-")); /* no v1 bare connection protocol */
2980 verstring = dupprintf("SSH-%s-%s\012",
2981 (ssh_versioncmp(svers, "1.5") <= 0 ?
2986 ssh_fix_verstring(verstring + strlen(protoname));
2988 if (ssh->version == 2) {
2991 * Record our version string.
2993 len = strcspn(verstring, "\015\012");
2994 ssh->v_c = snewn(len + 1, char);
2995 memcpy(ssh->v_c, verstring, len);
2999 logeventf(ssh, "We claim version: %.*s",
3000 strcspn(verstring, "\015\012"), verstring);
3001 s_write(ssh, verstring, strlen(verstring));
3005 static int do_ssh_init(Ssh ssh, unsigned char c)
3007 static const char protoname[] = "SSH-";
3009 struct do_ssh_init_state {
3018 crState(do_ssh_init_state);
3022 /* Search for a line beginning with the protocol name prefix in
3025 for (s->i = 0; protoname[s->i]; s->i++) {
3026 if ((char)c != protoname[s->i]) goto no;
3036 s->vstrsize = sizeof(protoname) + 16;
3037 s->vstring = snewn(s->vstrsize, char);
3038 strcpy(s->vstring, protoname);
3039 s->vslen = strlen(protoname);
3042 if (s->vslen >= s->vstrsize - 1) {
3044 s->vstring = sresize(s->vstring, s->vstrsize, char);
3046 s->vstring[s->vslen++] = c;
3049 s->version[s->i] = '\0';
3051 } else if (s->i < sizeof(s->version) - 1)
3052 s->version[s->i++] = c;
3053 } else if (c == '\012')
3055 crReturn(1); /* get another char */
3058 ssh->agentfwd_enabled = FALSE;
3059 ssh->rdpkt2_state.incoming_sequence = 0;
3061 s->vstring[s->vslen] = 0;
3062 s->vstring[strcspn(s->vstring, "\015\012")] = '\0';/* remove EOL chars */
3063 logeventf(ssh, "Server version: %s", s->vstring);
3064 ssh_detect_bugs(ssh, s->vstring);
3067 * Decide which SSH protocol version to support.
3070 /* Anything strictly below "2.0" means protocol 1 is supported. */
3071 s->proto1 = ssh_versioncmp(s->version, "2.0") < 0;
3072 /* Anything greater or equal to "1.99" means protocol 2 is supported. */
3073 s->proto2 = ssh_versioncmp(s->version, "1.99") >= 0;
3075 if (conf_get_int(ssh->conf, CONF_sshprot) == 0 && !s->proto1) {
3076 bombout(("SSH protocol version 1 required by configuration but "
3077 "not provided by server"));
3080 if (conf_get_int(ssh->conf, CONF_sshprot) == 3 && !s->proto2) {
3081 bombout(("SSH protocol version 2 required by configuration but "
3082 "not provided by server"));
3086 if (s->proto2 && (conf_get_int(ssh->conf, CONF_sshprot) >= 2 || !s->proto1))
3091 logeventf(ssh, "Using SSH protocol version %d", ssh->version);
3093 /* Send the version string, if we haven't already */
3094 if (conf_get_int(ssh->conf, CONF_sshprot) != 3)
3095 ssh_send_verstring(ssh, protoname, s->version);
3097 if (ssh->version == 2) {
3100 * Record their version string.
3102 len = strcspn(s->vstring, "\015\012");
3103 ssh->v_s = snewn(len + 1, char);
3104 memcpy(ssh->v_s, s->vstring, len);
3108 * Initialise SSH-2 protocol.
3110 ssh->protocol = ssh2_protocol;
3111 ssh2_protocol_setup(ssh);
3112 ssh->s_rdpkt = ssh2_rdpkt;
3115 * Initialise SSH-1 protocol.
3117 ssh->protocol = ssh1_protocol;
3118 ssh1_protocol_setup(ssh);
3119 ssh->s_rdpkt = ssh1_rdpkt;
3121 if (ssh->version == 2)
3122 do_ssh2_transport(ssh, NULL, -1, NULL);
3124 update_specials_menu(ssh->frontend);
3125 ssh->state = SSH_STATE_BEFORE_SIZE;
3126 ssh->pinger = pinger_new(ssh->conf, &ssh_backend, ssh);
3133 static int do_ssh_connection_init(Ssh ssh, unsigned char c)
3136 * Ordinary SSH begins with the banner "SSH-x.y-...". This is just
3137 * the ssh-connection part, extracted and given a trivial binary
3138 * packet protocol, so we replace 'SSH-' at the start with a new
3139 * name. In proper SSH style (though of course this part of the
3140 * proper SSH protocol _isn't_ subject to this kind of
3141 * DNS-domain-based extension), we define the new name in our
3144 static const char protoname[] =
3145 "SSHCONNECTION@putty.projects.tartarus.org-";
3147 struct do_ssh_connection_init_state {
3155 crState(do_ssh_connection_init_state);
3159 /* Search for a line beginning with the protocol name prefix in
3162 for (s->i = 0; protoname[s->i]; s->i++) {
3163 if ((char)c != protoname[s->i]) goto no;
3173 s->vstrsize = sizeof(protoname) + 16;
3174 s->vstring = snewn(s->vstrsize, char);
3175 strcpy(s->vstring, protoname);
3176 s->vslen = strlen(protoname);
3179 if (s->vslen >= s->vstrsize - 1) {
3181 s->vstring = sresize(s->vstring, s->vstrsize, char);
3183 s->vstring[s->vslen++] = c;
3186 s->version[s->i] = '\0';
3188 } else if (s->i < sizeof(s->version) - 1)
3189 s->version[s->i++] = c;
3190 } else if (c == '\012')
3192 crReturn(1); /* get another char */
3195 ssh->agentfwd_enabled = FALSE;
3196 ssh->rdpkt2_bare_state.incoming_sequence = 0;
3198 s->vstring[s->vslen] = 0;
3199 s->vstring[strcspn(s->vstring, "\015\012")] = '\0';/* remove EOL chars */
3200 logeventf(ssh, "Server version: %s", s->vstring);
3201 ssh_detect_bugs(ssh, s->vstring);
3204 * Decide which SSH protocol version to support. This is easy in
3205 * bare ssh-connection mode: only 2.0 is legal.
3207 if (ssh_versioncmp(s->version, "2.0") < 0) {
3208 bombout(("Server announces compatibility with SSH-1 in bare ssh-connection protocol"));
3211 if (conf_get_int(ssh->conf, CONF_sshprot) == 0) {
3212 bombout(("Bare ssh-connection protocol cannot be run in SSH-1-only mode"));
3218 logeventf(ssh, "Using bare ssh-connection protocol");
3220 /* Send the version string, if we haven't already */
3221 ssh_send_verstring(ssh, protoname, s->version);
3224 * Initialise bare connection protocol.
3226 ssh->protocol = ssh2_bare_connection_protocol;
3227 ssh2_bare_connection_protocol_setup(ssh);
3228 ssh->s_rdpkt = ssh2_bare_connection_rdpkt;
3230 update_specials_menu(ssh->frontend);
3231 ssh->state = SSH_STATE_BEFORE_SIZE;
3232 ssh->pinger = pinger_new(ssh->conf, &ssh_backend, ssh);
3235 * Get authconn (really just conn) under way.
3237 do_ssh2_authconn(ssh, NULL, 0, NULL);
3244 static void ssh_process_incoming_data(Ssh ssh,
3245 unsigned char **data, int *datalen)
3247 struct Packet *pktin;
3249 pktin = ssh->s_rdpkt(ssh, data, datalen);
3251 ssh->protocol(ssh, NULL, 0, pktin);
3252 ssh_free_packet(pktin);
3256 static void ssh_queue_incoming_data(Ssh ssh,
3257 unsigned char **data, int *datalen)
3259 bufchain_add(&ssh->queued_incoming_data, *data, *datalen);
3264 static void ssh_process_queued_incoming_data(Ssh ssh)
3267 unsigned char *data;
3270 while (!ssh->frozen && bufchain_size(&ssh->queued_incoming_data)) {
3271 bufchain_prefix(&ssh->queued_incoming_data, &vdata, &len);
3275 while (!ssh->frozen && len > 0)
3276 ssh_process_incoming_data(ssh, &data, &len);
3279 bufchain_consume(&ssh->queued_incoming_data, origlen - len);
3283 static void ssh_set_frozen(Ssh ssh, int frozen)
3286 sk_set_frozen(ssh->s, frozen);
3287 ssh->frozen = frozen;
3290 static void ssh_gotdata(Ssh ssh, unsigned char *data, int datalen)
3292 /* Log raw data, if we're in that mode. */
3294 log_packet(ssh->logctx, PKT_INCOMING, -1, NULL, data, datalen,
3295 0, NULL, NULL, 0, NULL);
3297 crBegin(ssh->ssh_gotdata_crstate);
3300 * To begin with, feed the characters one by one to the
3301 * protocol initialisation / selection function do_ssh_init().
3302 * When that returns 0, we're done with the initial greeting
3303 * exchange and can move on to packet discipline.
3306 int ret; /* need not be kept across crReturn */
3308 crReturnV; /* more data please */
3309 ret = ssh->do_ssh_init(ssh, *data);
3317 * We emerge from that loop when the initial negotiation is
3318 * over and we have selected an s_rdpkt function. Now pass
3319 * everything to s_rdpkt, and then pass the resulting packets
3320 * to the proper protocol handler.
3324 while (bufchain_size(&ssh->queued_incoming_data) > 0 || datalen > 0) {
3326 ssh_queue_incoming_data(ssh, &data, &datalen);
3327 /* This uses up all data and cannot cause anything interesting
3328 * to happen; indeed, for anything to happen at all, we must
3329 * return, so break out. */
3331 } else if (bufchain_size(&ssh->queued_incoming_data) > 0) {
3332 /* This uses up some or all data, and may freeze the
3334 ssh_process_queued_incoming_data(ssh);
3336 /* This uses up some or all data, and may freeze the
3338 ssh_process_incoming_data(ssh, &data, &datalen);
3340 /* FIXME this is probably EBW. */
3341 if (ssh->state == SSH_STATE_CLOSED)
3344 /* We're out of data. Go and get some more. */
3350 static int ssh_do_close(Ssh ssh, int notify_exit)
3353 struct ssh_channel *c;
3355 ssh->state = SSH_STATE_CLOSED;
3356 expire_timer_context(ssh);
3361 notify_remote_exit(ssh->frontend);
3366 * Now we must shut down any port- and X-forwarded channels going
3367 * through this connection.
3369 if (ssh->channels) {
3370 while (NULL != (c = index234(ssh->channels, 0))) {
3373 x11_close(c->u.x11.xconn);
3376 case CHAN_SOCKDATA_DORMANT:
3377 pfd_close(c->u.pfd.pf);
3380 del234(ssh->channels, c); /* moving next one to index 0 */
3381 if (ssh->version == 2)
3382 bufchain_clear(&c->v.v2.outbuffer);
3387 * Go through port-forwardings, and close any associated
3388 * listening sockets.
3390 if (ssh->portfwds) {
3391 struct ssh_portfwd *pf;
3392 while (NULL != (pf = index234(ssh->portfwds, 0))) {
3393 /* Dispose of any listening socket. */
3395 pfl_terminate(pf->local);
3396 del234(ssh->portfwds, pf); /* moving next one to index 0 */
3399 freetree234(ssh->portfwds);
3400 ssh->portfwds = NULL;
3404 * Also stop attempting to connection-share.
3406 if (ssh->connshare) {
3407 sharestate_free(ssh->connshare);
3408 ssh->connshare = NULL;
3414 static void ssh_socket_log(Plug plug, int type, SockAddr addr, int port,
3415 const char *error_msg, int error_code)
3417 Ssh ssh = (Ssh) plug;
3418 char addrbuf[256], *msg;
3420 if (ssh->attempting_connshare) {
3422 * While we're attempting connection sharing, don't loudly log
3423 * everything that happens. Real TCP connections need to be
3424 * logged when we _start_ trying to connect, because it might
3425 * be ages before they respond if something goes wrong; but
3426 * connection sharing is local and quick to respond, and it's
3427 * sufficient to simply wait and see whether it worked
3431 sk_getaddr(addr, addrbuf, lenof(addrbuf));
3434 if (sk_addr_needs_port(addr)) {
3435 msg = dupprintf("Connecting to %s port %d", addrbuf, port);
3437 msg = dupprintf("Connecting to %s", addrbuf);
3440 msg = dupprintf("Failed to connect to %s: %s", addrbuf, error_msg);
3448 void ssh_connshare_log(Ssh ssh, int event, const char *logtext,
3449 const char *ds_err, const char *us_err)
3451 if (event == SHARE_NONE) {
3452 /* In this case, 'logtext' is an error message indicating a
3453 * reason why connection sharing couldn't be set up _at all_.
3454 * Failing that, ds_err and us_err indicate why we couldn't be
3455 * a downstream and an upstream respectively. */
3457 logeventf(ssh, "Could not set up connection sharing: %s", logtext);
3460 logeventf(ssh, "Could not set up connection sharing"
3461 " as downstream: %s", ds_err);
3463 logeventf(ssh, "Could not set up connection sharing"
3464 " as upstream: %s", us_err);
3466 } else if (event == SHARE_DOWNSTREAM) {
3467 /* In this case, 'logtext' is a local endpoint address */
3468 logeventf(ssh, "Using existing shared connection at %s", logtext);
3469 /* Also we should mention this in the console window to avoid
3470 * confusing users as to why this window doesn't behave the
3472 if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
3473 c_write_str(ssh,"Reusing a shared connection to this server.\r\n");
3475 } else if (event == SHARE_UPSTREAM) {
3476 /* In this case, 'logtext' is a local endpoint address too */
3477 logeventf(ssh, "Sharing this connection at %s", logtext);
3481 static int ssh_closing(Plug plug, const char *error_msg, int error_code,
3484 Ssh ssh = (Ssh) plug;
3485 int need_notify = ssh_do_close(ssh, FALSE);
3488 if (!ssh->close_expected)
3489 error_msg = "Server unexpectedly closed network connection";
3491 error_msg = "Server closed network connection";
3494 if (ssh->close_expected && ssh->clean_exit && ssh->exitcode < 0)
3498 notify_remote_exit(ssh->frontend);
3501 logevent(error_msg);
3502 if (!ssh->close_expected || !ssh->clean_exit)
3503 connection_fatal(ssh->frontend, "%s", error_msg);
3507 static int ssh_receive(Plug plug, int urgent, char *data, int len)
3509 Ssh ssh = (Ssh) plug;
3510 ssh_gotdata(ssh, (unsigned char *)data, len);
3511 if (ssh->state == SSH_STATE_CLOSED) {
3512 ssh_do_close(ssh, TRUE);
3518 static void ssh_sent(Plug plug, int bufsize)
3520 Ssh ssh = (Ssh) plug;
3522 * If the send backlog on the SSH socket itself clears, we
3523 * should unthrottle the whole world if it was throttled.
3525 if (bufsize < SSH_MAX_BACKLOG)
3526 ssh_throttle_all(ssh, 0, bufsize);
3530 * Connect to specified host and port.
3531 * Returns an error message, or NULL on success.
3532 * Also places the canonical host name into `realhost'. It must be
3533 * freed by the caller.
3535 static const char *connect_to_host(Ssh ssh, char *host, int port,
3536 char **realhost, int nodelay, int keepalive)
3538 static const struct plug_function_table fn_table = {
3549 int addressfamily, sshprot;
3551 loghost = conf_get_str(ssh->conf, CONF_loghost);
3556 tmphost = dupstr(loghost);
3557 ssh->savedport = 22; /* default ssh port */
3560 * A colon suffix on the hostname string also lets us affect
3561 * savedport. (Unless there are multiple colons, in which case
3562 * we assume this is an unbracketed IPv6 literal.)
3564 colon = host_strrchr(tmphost, ':');
3565 if (colon && colon == host_strchr(tmphost, ':')) {
3568 ssh->savedport = atoi(colon);
3571 ssh->savedhost = host_strduptrim(tmphost);
3574 ssh->savedhost = host_strduptrim(host);
3576 port = 22; /* default ssh port */
3577 ssh->savedport = port;
3580 ssh->fn = &fn_table; /* make 'ssh' usable as a Plug */
3583 * Try connection-sharing, in case that means we don't open a
3584 * socket after all. ssh_connection_sharing_init will connect to a
3585 * previously established upstream if it can, and failing that,
3586 * establish a listening socket for _us_ to be the upstream. In
3587 * the latter case it will return NULL just as if it had done
3588 * nothing, because here we only need to care if we're a
3589 * downstream and need to do our connection setup differently.
3591 ssh->connshare = NULL;
3592 ssh->attempting_connshare = TRUE; /* affects socket logging behaviour */
3593 ssh->s = ssh_connection_sharing_init(ssh->savedhost, ssh->savedport,
3594 ssh->conf, ssh, &ssh->connshare);
3595 ssh->attempting_connshare = FALSE;
3596 if (ssh->s != NULL) {
3598 * We are a downstream.
3600 ssh->bare_connection = TRUE;
3601 ssh->do_ssh_init = do_ssh_connection_init;
3602 ssh->fullhostname = NULL;
3603 *realhost = dupstr(host); /* best we can do */
3606 * We're not a downstream, so open a normal socket.
3608 ssh->do_ssh_init = do_ssh_init;
3613 addressfamily = conf_get_int(ssh->conf, CONF_addressfamily);
3614 logeventf(ssh, "Looking up host \"%s\"%s", host,
3615 (addressfamily == ADDRTYPE_IPV4 ? " (IPv4)" :
3616 (addressfamily == ADDRTYPE_IPV6 ? " (IPv6)" : "")));
3617 addr = name_lookup(host, port, realhost, ssh->conf, addressfamily);
3618 if ((err = sk_addr_error(addr)) != NULL) {
3622 ssh->fullhostname = dupstr(*realhost); /* save in case of GSSAPI */
3624 ssh->s = new_connection(addr, *realhost, port,
3625 0, 1, nodelay, keepalive,
3626 (Plug) ssh, ssh->conf);
3627 if ((err = sk_socket_error(ssh->s)) != NULL) {
3629 notify_remote_exit(ssh->frontend);
3635 * If the SSH version number's fixed, set it now, and if it's SSH-2,
3636 * send the version string too.
3638 sshprot = conf_get_int(ssh->conf, CONF_sshprot);
3641 if (sshprot == 3 && !ssh->bare_connection) {
3643 ssh_send_verstring(ssh, "SSH-", NULL);
3647 * loghost, if configured, overrides realhost.
3651 *realhost = dupstr(loghost);
3658 * Throttle or unthrottle the SSH connection.
3660 static void ssh_throttle_conn(Ssh ssh, int adjust)
3662 int old_count = ssh->conn_throttle_count;
3663 ssh->conn_throttle_count += adjust;
3664 assert(ssh->conn_throttle_count >= 0);
3665 if (ssh->conn_throttle_count && !old_count) {
3666 ssh_set_frozen(ssh, 1);
3667 } else if (!ssh->conn_throttle_count && old_count) {
3668 ssh_set_frozen(ssh, 0);
3673 * Throttle or unthrottle _all_ local data streams (for when sends
3674 * on the SSH connection itself back up).
3676 static void ssh_throttle_all(Ssh ssh, int enable, int bufsize)
3679 struct ssh_channel *c;
3681 if (enable == ssh->throttled_all)
3683 ssh->throttled_all = enable;
3684 ssh->overall_bufsize = bufsize;
3687 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
3689 case CHAN_MAINSESSION:
3691 * This is treated separately, outside the switch.
3695 x11_override_throttle(c->u.x11.xconn, enable);
3698 /* Agent channels require no buffer management. */
3701 pfd_override_throttle(c->u.pfd.pf, enable);
3707 static void ssh_agent_callback(void *sshv, void *reply, int replylen)
3709 Ssh ssh = (Ssh) sshv;
3711 ssh->agent_response = reply;
3712 ssh->agent_response_len = replylen;
3714 if (ssh->version == 1)
3715 do_ssh1_login(ssh, NULL, -1, NULL);
3717 do_ssh2_authconn(ssh, NULL, -1, NULL);
3720 static void ssh_dialog_callback(void *sshv, int ret)
3722 Ssh ssh = (Ssh) sshv;
3724 ssh->user_response = ret;
3726 if (ssh->version == 1)
3727 do_ssh1_login(ssh, NULL, -1, NULL);
3729 do_ssh2_transport(ssh, NULL, -1, NULL);
3732 * This may have unfrozen the SSH connection, so do a
3735 ssh_process_queued_incoming_data(ssh);
3738 static void ssh_agentf_callback(void *cv, void *reply, int replylen)
3740 struct ssh_channel *c = (struct ssh_channel *)cv;
3742 void *sentreply = reply;
3744 c->u.a.outstanding_requests--;
3746 /* Fake SSH_AGENT_FAILURE. */
3747 sentreply = "\0\0\0\1\5";
3750 if (ssh->version == 2) {
3751 ssh2_add_channel_data(c, sentreply, replylen);
3754 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
3755 PKT_INT, c->remoteid,
3757 PKT_DATA, sentreply, replylen,
3763 * If we've already seen an incoming EOF but haven't sent an
3764 * outgoing one, this may be the moment to send it.
3766 if (c->u.a.outstanding_requests == 0 && (c->closes & CLOSES_RCVD_EOF))
3767 sshfwd_write_eof(c);
3771 * Client-initiated disconnection. Send a DISCONNECT if `wire_reason'
3772 * non-NULL, otherwise just close the connection. `client_reason' == NULL
3773 * => log `wire_reason'.
3775 static void ssh_disconnect(Ssh ssh, char *client_reason, char *wire_reason,
3776 int code, int clean_exit)
3780 client_reason = wire_reason;
3782 error = dupprintf("Disconnected: %s", client_reason);
3784 error = dupstr("Disconnected");
3786 if (ssh->version == 1) {
3787 send_packet(ssh, SSH1_MSG_DISCONNECT, PKT_STR, wire_reason,
3789 } else if (ssh->version == 2) {
3790 struct Packet *pktout = ssh2_pkt_init(SSH2_MSG_DISCONNECT);
3791 ssh2_pkt_adduint32(pktout, code);
3792 ssh2_pkt_addstring(pktout, wire_reason);
3793 ssh2_pkt_addstring(pktout, "en"); /* language tag */
3794 ssh2_pkt_send_noqueue(ssh, pktout);
3797 ssh->close_expected = TRUE;
3798 ssh->clean_exit = clean_exit;
3799 ssh_closing((Plug)ssh, error, 0, 0);
3803 int verify_ssh_manual_host_key(Ssh ssh, const char *fingerprint,
3804 const struct ssh_signkey *ssh2keytype,
3807 if (!conf_get_str_nthstrkey(ssh->conf, CONF_ssh_manual_hostkeys, 0)) {
3808 return -1; /* no manual keys configured */
3813 * The fingerprint string we've been given will have things
3814 * like 'ssh-rsa 2048' at the front of it. Strip those off and
3815 * narrow down to just the colon-separated hex block at the
3816 * end of the string.
3818 const char *p = strrchr(fingerprint, ' ');
3819 fingerprint = p ? p+1 : fingerprint;
3820 /* Quick sanity checks, including making sure it's in lowercase */
3821 assert(strlen(fingerprint) == 16*3 - 1);
3822 assert(fingerprint[2] == ':');
3823 assert(fingerprint[strspn(fingerprint, "0123456789abcdef:")] == 0);
3825 if (conf_get_str_str_opt(ssh->conf, CONF_ssh_manual_hostkeys,
3827 return 1; /* success */
3832 * Construct the base64-encoded public key blob and see if
3835 unsigned char *binblob;
3837 int binlen, atoms, i;
3838 binblob = ssh2keytype->public_blob(ssh2keydata, &binlen);
3839 atoms = (binlen + 2) / 3;
3840 base64blob = snewn(atoms * 4 + 1, char);
3841 for (i = 0; i < atoms; i++)
3842 base64_encode_atom(binblob + 3*i, binlen - 3*i, base64blob + 4*i);
3843 base64blob[atoms * 4] = '\0';
3845 if (conf_get_str_str_opt(ssh->conf, CONF_ssh_manual_hostkeys,
3848 return 1; /* success */
3857 * Handle the key exchange and user authentication phases.
3859 static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen,
3860 struct Packet *pktin)
3863 unsigned char cookie[8], *ptr;
3864 struct MD5Context md5c;
3865 struct do_ssh1_login_state {
3868 unsigned char *rsabuf;
3869 const unsigned char *keystr1, *keystr2;
3870 unsigned long supported_ciphers_mask, supported_auths_mask;
3871 int tried_publickey, tried_agent;
3872 int tis_auth_refused, ccard_auth_refused;
3873 unsigned char session_id[16];
3875 void *publickey_blob;
3876 int publickey_bloblen;
3877 char *publickey_comment;
3878 int publickey_encrypted;
3879 prompts_t *cur_prompt;
3882 unsigned char request[5], *response, *p;
3892 struct RSAKey servkey, hostkey;
3894 crState(do_ssh1_login_state);
3901 if (pktin->type != SSH1_SMSG_PUBLIC_KEY) {
3902 bombout(("Public key packet not received"));
3906 logevent("Received public keys");
3908 ptr = ssh_pkt_getdata(pktin, 8);
3910 bombout(("SSH-1 public key packet stopped before random cookie"));
3913 memcpy(cookie, ptr, 8);
3915 if (!ssh1_pkt_getrsakey(pktin, &s->servkey, &s->keystr1) ||
3916 !ssh1_pkt_getrsakey(pktin, &s->hostkey, &s->keystr2)) {
3917 bombout(("Failed to read SSH-1 public keys from public key packet"));
3922 * Log the host key fingerprint.
3926 logevent("Host key fingerprint is:");
3927 strcpy(logmsg, " ");
3928 s->hostkey.comment = NULL;
3929 rsa_fingerprint(logmsg + strlen(logmsg),
3930 sizeof(logmsg) - strlen(logmsg), &s->hostkey);
3934 ssh->v1_remote_protoflags = ssh_pkt_getuint32(pktin);
3935 s->supported_ciphers_mask = ssh_pkt_getuint32(pktin);
3936 s->supported_auths_mask = ssh_pkt_getuint32(pktin);
3937 if ((ssh->remote_bugs & BUG_CHOKES_ON_RSA))
3938 s->supported_auths_mask &= ~(1 << SSH1_AUTH_RSA);
3940 ssh->v1_local_protoflags =
3941 ssh->v1_remote_protoflags & SSH1_PROTOFLAGS_SUPPORTED;
3942 ssh->v1_local_protoflags |= SSH1_PROTOFLAG_SCREEN_NUMBER;
3945 MD5Update(&md5c, s->keystr2, s->hostkey.bytes);
3946 MD5Update(&md5c, s->keystr1, s->servkey.bytes);
3947 MD5Update(&md5c, cookie, 8);
3948 MD5Final(s->session_id, &md5c);
3950 for (i = 0; i < 32; i++)
3951 ssh->session_key[i] = random_byte();
3954 * Verify that the `bits' and `bytes' parameters match.
3956 if (s->hostkey.bits > s->hostkey.bytes * 8 ||
3957 s->servkey.bits > s->servkey.bytes * 8) {
3958 bombout(("SSH-1 public keys were badly formatted"));
3962 s->len = (s->hostkey.bytes > s->servkey.bytes ?
3963 s->hostkey.bytes : s->servkey.bytes);
3965 s->rsabuf = snewn(s->len, unsigned char);
3968 * Verify the host key.
3972 * First format the key into a string.
3974 int len = rsastr_len(&s->hostkey);
3975 char fingerprint[100];
3976 char *keystr = snewn(len, char);
3977 rsastr_fmt(keystr, &s->hostkey);
3978 rsa_fingerprint(fingerprint, sizeof(fingerprint), &s->hostkey);
3980 /* First check against manually configured host keys. */
3981 s->dlgret = verify_ssh_manual_host_key(ssh, fingerprint, NULL, NULL);
3982 if (s->dlgret == 0) { /* did not match */
3983 bombout(("Host key did not appear in manually configured list"));
3986 } else if (s->dlgret < 0) { /* none configured; use standard handling */
3987 ssh_set_frozen(ssh, 1);
3988 s->dlgret = verify_ssh_host_key(ssh->frontend,
3989 ssh->savedhost, ssh->savedport,
3990 "rsa", keystr, fingerprint,
3991 ssh_dialog_callback, ssh);
3993 if (s->dlgret < 0) {
3997 bombout(("Unexpected data from server while waiting"
3998 " for user host key response"));
4001 } while (pktin || inlen > 0);
4002 s->dlgret = ssh->user_response;
4004 ssh_set_frozen(ssh, 0);
4006 if (s->dlgret == 0) {
4007 ssh_disconnect(ssh, "User aborted at host key verification",
4016 for (i = 0; i < 32; i++) {
4017 s->rsabuf[i] = ssh->session_key[i];
4019 s->rsabuf[i] ^= s->session_id[i];
4022 if (s->hostkey.bytes > s->servkey.bytes) {
4023 ret = rsaencrypt(s->rsabuf, 32, &s->servkey);
4025 ret = rsaencrypt(s->rsabuf, s->servkey.bytes, &s->hostkey);
4027 ret = rsaencrypt(s->rsabuf, 32, &s->hostkey);
4029 ret = rsaencrypt(s->rsabuf, s->hostkey.bytes, &s->servkey);
4032 bombout(("SSH-1 public key encryptions failed due to bad formatting"));
4036 logevent("Encrypted session key");
4039 int cipher_chosen = 0, warn = 0;
4040 char *cipher_string = NULL;
4042 for (i = 0; !cipher_chosen && i < CIPHER_MAX; i++) {
4043 int next_cipher = conf_get_int_int(ssh->conf,
4044 CONF_ssh_cipherlist, i);
4045 if (next_cipher == CIPHER_WARN) {
4046 /* If/when we choose a cipher, warn about it */
4048 } else if (next_cipher == CIPHER_AES) {
4049 /* XXX Probably don't need to mention this. */
4050 logevent("AES not supported in SSH-1, skipping");
4052 switch (next_cipher) {
4053 case CIPHER_3DES: s->cipher_type = SSH_CIPHER_3DES;
4054 cipher_string = "3DES"; break;
4055 case CIPHER_BLOWFISH: s->cipher_type = SSH_CIPHER_BLOWFISH;
4056 cipher_string = "Blowfish"; break;
4057 case CIPHER_DES: s->cipher_type = SSH_CIPHER_DES;
4058 cipher_string = "single-DES"; break;
4060 if (s->supported_ciphers_mask & (1 << s->cipher_type))
4064 if (!cipher_chosen) {
4065 if ((s->supported_ciphers_mask & (1 << SSH_CIPHER_3DES)) == 0)
4066 bombout(("Server violates SSH-1 protocol by not "
4067 "supporting 3DES encryption"));
4069 /* shouldn't happen */
4070 bombout(("No supported ciphers found"));
4074 /* Warn about chosen cipher if necessary. */
4076 ssh_set_frozen(ssh, 1);
4077 s->dlgret = askalg(ssh->frontend, "cipher", cipher_string,
4078 ssh_dialog_callback, ssh);
4079 if (s->dlgret < 0) {
4083 bombout(("Unexpected data from server while waiting"
4084 " for user response"));
4087 } while (pktin || inlen > 0);
4088 s->dlgret = ssh->user_response;
4090 ssh_set_frozen(ssh, 0);
4091 if (s->dlgret == 0) {
4092 ssh_disconnect(ssh, "User aborted at cipher warning", NULL,
4099 switch (s->cipher_type) {
4100 case SSH_CIPHER_3DES:
4101 logevent("Using 3DES encryption");
4103 case SSH_CIPHER_DES:
4104 logevent("Using single-DES encryption");
4106 case SSH_CIPHER_BLOWFISH:
4107 logevent("Using Blowfish encryption");
4111 send_packet(ssh, SSH1_CMSG_SESSION_KEY,
4112 PKT_CHAR, s->cipher_type,
4113 PKT_DATA, cookie, 8,
4114 PKT_CHAR, (s->len * 8) >> 8, PKT_CHAR, (s->len * 8) & 0xFF,
4115 PKT_DATA, s->rsabuf, s->len,
4116 PKT_INT, ssh->v1_local_protoflags, PKT_END);
4118 logevent("Trying to enable encryption...");
4122 ssh->cipher = (s->cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 :
4123 s->cipher_type == SSH_CIPHER_DES ? &ssh_des :
4125 ssh->v1_cipher_ctx = ssh->cipher->make_context();
4126 ssh->cipher->sesskey(ssh->v1_cipher_ctx, ssh->session_key);
4127 logeventf(ssh, "Initialised %s encryption", ssh->cipher->text_name);
4129 ssh->crcda_ctx = crcda_make_context();
4130 logevent("Installing CRC compensation attack detector");
4132 if (s->servkey.modulus) {
4133 sfree(s->servkey.modulus);
4134 s->servkey.modulus = NULL;
4136 if (s->servkey.exponent) {
4137 sfree(s->servkey.exponent);
4138 s->servkey.exponent = NULL;
4140 if (s->hostkey.modulus) {
4141 sfree(s->hostkey.modulus);
4142 s->hostkey.modulus = NULL;
4144 if (s->hostkey.exponent) {
4145 sfree(s->hostkey.exponent);
4146 s->hostkey.exponent = NULL;
4150 if (pktin->type != SSH1_SMSG_SUCCESS) {
4151 bombout(("Encryption not successfully enabled"));
4155 logevent("Successfully started encryption");
4157 fflush(stdout); /* FIXME eh? */
4159 if ((ssh->username = get_remote_username(ssh->conf)) == NULL) {
4160 int ret; /* need not be kept over crReturn */
4161 s->cur_prompt = new_prompts(ssh->frontend);
4162 s->cur_prompt->to_server = TRUE;
4163 s->cur_prompt->name = dupstr("SSH login name");
4164 add_prompt(s->cur_prompt, dupstr("login as: "), TRUE);
4165 ret = get_userpass_input(s->cur_prompt, NULL, 0);
4168 crWaitUntil(!pktin);
4169 ret = get_userpass_input(s->cur_prompt, in, inlen);
4174 * Failed to get a username. Terminate.
4176 free_prompts(s->cur_prompt);
4177 ssh_disconnect(ssh, "No username provided", NULL, 0, TRUE);
4180 ssh->username = dupstr(s->cur_prompt->prompts[0]->result);
4181 free_prompts(s->cur_prompt);
4184 send_packet(ssh, SSH1_CMSG_USER, PKT_STR, ssh->username, PKT_END);
4186 char *userlog = dupprintf("Sent username \"%s\"", ssh->username);
4188 if (flags & FLAG_INTERACTIVE &&
4189 (!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) {
4190 c_write_str(ssh, userlog);
4191 c_write_str(ssh, "\r\n");
4199 if ((s->supported_auths_mask & (1 << SSH1_AUTH_RSA)) == 0) {
4200 /* We must not attempt PK auth. Pretend we've already tried it. */
4201 s->tried_publickey = s->tried_agent = 1;
4203 s->tried_publickey = s->tried_agent = 0;
4205 s->tis_auth_refused = s->ccard_auth_refused = 0;
4207 * Load the public half of any configured keyfile for later use.
4209 s->keyfile = conf_get_filename(ssh->conf, CONF_keyfile);
4210 if (!filename_is_null(s->keyfile)) {
4212 logeventf(ssh, "Reading private key file \"%.150s\"",
4213 filename_to_str(s->keyfile));
4214 keytype = key_type(s->keyfile);
4215 if (keytype == SSH_KEYTYPE_SSH1) {
4217 if (rsakey_pubblob(s->keyfile,
4218 &s->publickey_blob, &s->publickey_bloblen,
4219 &s->publickey_comment, &error)) {
4220 s->publickey_encrypted = rsakey_encrypted(s->keyfile,
4224 logeventf(ssh, "Unable to load private key (%s)", error);
4225 msgbuf = dupprintf("Unable to load private key file "
4226 "\"%.150s\" (%s)\r\n",
4227 filename_to_str(s->keyfile),
4229 c_write_str(ssh, msgbuf);
4231 s->publickey_blob = NULL;
4235 logeventf(ssh, "Unable to use this key file (%s)",
4236 key_type_to_str(keytype));
4237 msgbuf = dupprintf("Unable to use key file \"%.150s\""
4239 filename_to_str(s->keyfile),
4240 key_type_to_str(keytype));
4241 c_write_str(ssh, msgbuf);
4243 s->publickey_blob = NULL;
4246 s->publickey_blob = NULL;
4248 while (pktin->type == SSH1_SMSG_FAILURE) {
4249 s->pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
4251 if (conf_get_int(ssh->conf, CONF_tryagent) && agent_exists() && !s->tried_agent) {
4253 * Attempt RSA authentication using Pageant.
4259 logevent("Pageant is running. Requesting keys.");
4261 /* Request the keys held by the agent. */
4262 PUT_32BIT(s->request, 1);
4263 s->request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES;
4264 if (!agent_query(s->request, 5, &r, &s->responselen,
4265 ssh_agent_callback, ssh)) {
4269 bombout(("Unexpected data from server while waiting"
4270 " for agent response"));
4273 } while (pktin || inlen > 0);
4274 r = ssh->agent_response;
4275 s->responselen = ssh->agent_response_len;
4277 s->response = (unsigned char *) r;
4278 if (s->response && s->responselen >= 5 &&
4279 s->response[4] == SSH1_AGENT_RSA_IDENTITIES_ANSWER) {
4280 s->p = s->response + 5;
4281 s->nkeys = toint(GET_32BIT(s->p));
4283 logeventf(ssh, "Pageant reported negative key count %d",
4288 logeventf(ssh, "Pageant has %d SSH-1 keys", s->nkeys);
4289 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
4290 unsigned char *pkblob = s->p;
4294 do { /* do while (0) to make breaking easy */
4295 n = ssh1_read_bignum
4296 (s->p, toint(s->responselen-(s->p-s->response)),
4301 n = ssh1_read_bignum
4302 (s->p, toint(s->responselen-(s->p-s->response)),
4307 if (s->responselen - (s->p-s->response) < 4)
4309 s->commentlen = toint(GET_32BIT(s->p));
4311 if (s->commentlen < 0 ||
4312 toint(s->responselen - (s->p-s->response)) <
4315 s->commentp = (char *)s->p;
4316 s->p += s->commentlen;
4320 logevent("Pageant key list packet was truncated");
4324 if (s->publickey_blob) {
4325 if (!memcmp(pkblob, s->publickey_blob,
4326 s->publickey_bloblen)) {
4327 logeventf(ssh, "Pageant key #%d matches "
4328 "configured key file", s->keyi);
4329 s->tried_publickey = 1;
4331 /* Skip non-configured key */
4334 logeventf(ssh, "Trying Pageant key #%d", s->keyi);
4335 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
4336 PKT_BIGNUM, s->key.modulus, PKT_END);
4338 if (pktin->type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
4339 logevent("Key refused");
4342 logevent("Received RSA challenge");
4343 if ((s->challenge = ssh1_pkt_getmp(pktin)) == NULL) {
4344 bombout(("Server's RSA challenge was badly formatted"));
4349 char *agentreq, *q, *ret;
4352 len = 1 + 4; /* message type, bit count */
4353 len += ssh1_bignum_length(s->key.exponent);
4354 len += ssh1_bignum_length(s->key.modulus);
4355 len += ssh1_bignum_length(s->challenge);
4356 len += 16; /* session id */
4357 len += 4; /* response format */
4358 agentreq = snewn(4 + len, char);
4359 PUT_32BIT(agentreq, len);
4361 *q++ = SSH1_AGENTC_RSA_CHALLENGE;
4362 PUT_32BIT(q, bignum_bitcount(s->key.modulus));
4364 q += ssh1_write_bignum(q, s->key.exponent);
4365 q += ssh1_write_bignum(q, s->key.modulus);
4366 q += ssh1_write_bignum(q, s->challenge);
4367 memcpy(q, s->session_id, 16);
4369 PUT_32BIT(q, 1); /* response format */
4370 if (!agent_query(agentreq, len + 4, &vret, &retlen,
4371 ssh_agent_callback, ssh)) {
4376 bombout(("Unexpected data from server"
4377 " while waiting for agent"
4381 } while (pktin || inlen > 0);
4382 vret = ssh->agent_response;
4383 retlen = ssh->agent_response_len;
4388 if (ret[4] == SSH1_AGENT_RSA_RESPONSE) {
4389 logevent("Sending Pageant's response");
4390 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
4391 PKT_DATA, ret + 5, 16,
4395 if (pktin->type == SSH1_SMSG_SUCCESS) {
4397 ("Pageant's response accepted");
4398 if (flags & FLAG_VERBOSE) {
4399 c_write_str(ssh, "Authenticated using"
4401 c_write(ssh, s->commentp,
4403 c_write_str(ssh, "\" from agent\r\n");
4408 ("Pageant's response not accepted");
4411 ("Pageant failed to answer challenge");
4415 logevent("No reply received from Pageant");
4418 freebn(s->key.exponent);
4419 freebn(s->key.modulus);
4420 freebn(s->challenge);
4425 if (s->publickey_blob && !s->tried_publickey)
4426 logevent("Configured key file not in Pageant");
4428 logevent("Failed to get reply from Pageant");
4433 if (s->publickey_blob && !s->tried_publickey) {
4435 * Try public key authentication with the specified
4438 int got_passphrase; /* need not be kept over crReturn */
4439 if (flags & FLAG_VERBOSE)
4440 c_write_str(ssh, "Trying public key authentication.\r\n");
4441 s->keyfile = conf_get_filename(ssh->conf, CONF_keyfile);
4442 logeventf(ssh, "Trying public key \"%s\"",
4443 filename_to_str(s->keyfile));
4444 s->tried_publickey = 1;
4445 got_passphrase = FALSE;
4446 while (!got_passphrase) {
4448 * Get a passphrase, if necessary.
4450 char *passphrase = NULL; /* only written after crReturn */
4452 if (!s->publickey_encrypted) {
4453 if (flags & FLAG_VERBOSE)
4454 c_write_str(ssh, "No passphrase required.\r\n");
4457 int ret; /* need not be kept over crReturn */
4458 s->cur_prompt = new_prompts(ssh->frontend);
4459 s->cur_prompt->to_server = FALSE;
4460 s->cur_prompt->name = dupstr("SSH key passphrase");
4461 add_prompt(s->cur_prompt,
4462 dupprintf("Passphrase for key \"%.100s\": ",
4463 s->publickey_comment), FALSE);
4464 ret = get_userpass_input(s->cur_prompt, NULL, 0);
4467 crWaitUntil(!pktin);
4468 ret = get_userpass_input(s->cur_prompt, in, inlen);
4472 /* Failed to get a passphrase. Terminate. */
4473 free_prompts(s->cur_prompt);
4474 ssh_disconnect(ssh, NULL, "Unable to authenticate",
4478 passphrase = dupstr(s->cur_prompt->prompts[0]->result);
4479 free_prompts(s->cur_prompt);
4482 * Try decrypting key with passphrase.
4484 s->keyfile = conf_get_filename(ssh->conf, CONF_keyfile);
4485 ret = loadrsakey(s->keyfile, &s->key, passphrase,
4488 smemclr(passphrase, strlen(passphrase));
4492 /* Correct passphrase. */
4493 got_passphrase = TRUE;
4494 } else if (ret == 0) {
4495 c_write_str(ssh, "Couldn't load private key from ");
4496 c_write_str(ssh, filename_to_str(s->keyfile));
4497 c_write_str(ssh, " (");
4498 c_write_str(ssh, error);
4499 c_write_str(ssh, ").\r\n");
4500 got_passphrase = FALSE;
4501 break; /* go and try something else */
4502 } else if (ret == -1) {
4503 c_write_str(ssh, "Wrong passphrase.\r\n"); /* FIXME */
4504 got_passphrase = FALSE;
4507 assert(0 && "unexpected return from loadrsakey()");
4508 got_passphrase = FALSE; /* placate optimisers */
4512 if (got_passphrase) {
4515 * Send a public key attempt.
4517 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
4518 PKT_BIGNUM, s->key.modulus, PKT_END);
4521 if (pktin->type == SSH1_SMSG_FAILURE) {
4522 c_write_str(ssh, "Server refused our public key.\r\n");
4523 continue; /* go and try something else */
4525 if (pktin->type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
4526 bombout(("Bizarre response to offer of public key"));
4532 unsigned char buffer[32];
4533 Bignum challenge, response;
4535 if ((challenge = ssh1_pkt_getmp(pktin)) == NULL) {
4536 bombout(("Server's RSA challenge was badly formatted"));
4539 response = rsadecrypt(challenge, &s->key);
4540 freebn(s->key.private_exponent);/* burn the evidence */
4542 for (i = 0; i < 32; i++) {
4543 buffer[i] = bignum_byte(response, 31 - i);
4547 MD5Update(&md5c, buffer, 32);
4548 MD5Update(&md5c, s->session_id, 16);
4549 MD5Final(buffer, &md5c);
4551 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
4552 PKT_DATA, buffer, 16, PKT_END);
4559 if (pktin->type == SSH1_SMSG_FAILURE) {
4560 if (flags & FLAG_VERBOSE)
4561 c_write_str(ssh, "Failed to authenticate with"
4562 " our public key.\r\n");
4563 continue; /* go and try something else */
4564 } else if (pktin->type != SSH1_SMSG_SUCCESS) {
4565 bombout(("Bizarre response to RSA authentication response"));
4569 break; /* we're through! */
4575 * Otherwise, try various forms of password-like authentication.
4577 s->cur_prompt = new_prompts(ssh->frontend);
4579 if (conf_get_int(ssh->conf, CONF_try_tis_auth) &&
4580 (s->supported_auths_mask & (1 << SSH1_AUTH_TIS)) &&
4581 !s->tis_auth_refused) {
4582 s->pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
4583 logevent("Requested TIS authentication");
4584 send_packet(ssh, SSH1_CMSG_AUTH_TIS, PKT_END);
4586 if (pktin->type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
4587 logevent("TIS authentication declined");
4588 if (flags & FLAG_INTERACTIVE)
4589 c_write_str(ssh, "TIS authentication refused.\r\n");
4590 s->tis_auth_refused = 1;
4595 char *instr_suf, *prompt;
4597 ssh_pkt_getstring(pktin, &challenge, &challengelen);
4599 bombout(("TIS challenge packet was badly formed"));
4602 logevent("Received TIS challenge");
4603 s->cur_prompt->to_server = TRUE;
4604 s->cur_prompt->name = dupstr("SSH TIS authentication");
4605 /* Prompt heuristic comes from OpenSSH */
4606 if (memchr(challenge, '\n', challengelen)) {
4607 instr_suf = dupstr("");
4608 prompt = dupprintf("%.*s", challengelen, challenge);
4610 instr_suf = dupprintf("%.*s", challengelen, challenge);
4611 prompt = dupstr("Response: ");
4613 s->cur_prompt->instruction =
4614 dupprintf("Using TIS authentication.%s%s",
4615 (*instr_suf) ? "\n" : "",
4617 s->cur_prompt->instr_reqd = TRUE;
4618 add_prompt(s->cur_prompt, prompt, FALSE);
4622 if (conf_get_int(ssh->conf, CONF_try_tis_auth) &&
4623 (s->supported_auths_mask & (1 << SSH1_AUTH_CCARD)) &&
4624 !s->ccard_auth_refused) {
4625 s->pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE;
4626 logevent("Requested CryptoCard authentication");
4627 send_packet(ssh, SSH1_CMSG_AUTH_CCARD, PKT_END);
4629 if (pktin->type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
4630 logevent("CryptoCard authentication declined");
4631 c_write_str(ssh, "CryptoCard authentication refused.\r\n");
4632 s->ccard_auth_refused = 1;
4637 char *instr_suf, *prompt;
4639 ssh_pkt_getstring(pktin, &challenge, &challengelen);
4641 bombout(("CryptoCard challenge packet was badly formed"));
4644 logevent("Received CryptoCard challenge");
4645 s->cur_prompt->to_server = TRUE;
4646 s->cur_prompt->name = dupstr("SSH CryptoCard authentication");
4647 s->cur_prompt->name_reqd = FALSE;
4648 /* Prompt heuristic comes from OpenSSH */
4649 if (memchr(challenge, '\n', challengelen)) {
4650 instr_suf = dupstr("");
4651 prompt = dupprintf("%.*s", challengelen, challenge);
4653 instr_suf = dupprintf("%.*s", challengelen, challenge);
4654 prompt = dupstr("Response: ");
4656 s->cur_prompt->instruction =
4657 dupprintf("Using CryptoCard authentication.%s%s",
4658 (*instr_suf) ? "\n" : "",
4660 s->cur_prompt->instr_reqd = TRUE;
4661 add_prompt(s->cur_prompt, prompt, FALSE);
4665 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
4666 if ((s->supported_auths_mask & (1 << SSH1_AUTH_PASSWORD)) == 0) {
4667 bombout(("No supported authentication methods available"));
4670 s->cur_prompt->to_server = TRUE;
4671 s->cur_prompt->name = dupstr("SSH password");
4672 add_prompt(s->cur_prompt, dupprintf("%s@%s's password: ",
4673 ssh->username, ssh->savedhost),
4678 * Show password prompt, having first obtained it via a TIS
4679 * or CryptoCard exchange if we're doing TIS or CryptoCard
4683 int ret; /* need not be kept over crReturn */
4684 ret = get_userpass_input(s->cur_prompt, NULL, 0);
4687 crWaitUntil(!pktin);
4688 ret = get_userpass_input(s->cur_prompt, in, inlen);
4693 * Failed to get a password (for example
4694 * because one was supplied on the command line
4695 * which has already failed to work). Terminate.
4697 free_prompts(s->cur_prompt);
4698 ssh_disconnect(ssh, NULL, "Unable to authenticate", 0, TRUE);
4703 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
4705 * Defence against traffic analysis: we send a
4706 * whole bunch of packets containing strings of
4707 * different lengths. One of these strings is the
4708 * password, in a SSH1_CMSG_AUTH_PASSWORD packet.
4709 * The others are all random data in
4710 * SSH1_MSG_IGNORE packets. This way a passive
4711 * listener can't tell which is the password, and
4712 * hence can't deduce the password length.
4714 * Anybody with a password length greater than 16
4715 * bytes is going to have enough entropy in their
4716 * password that a listener won't find it _that_
4717 * much help to know how long it is. So what we'll
4720 * - if password length < 16, we send 15 packets
4721 * containing string lengths 1 through 15
4723 * - otherwise, we let N be the nearest multiple
4724 * of 8 below the password length, and send 8
4725 * packets containing string lengths N through
4726 * N+7. This won't obscure the order of
4727 * magnitude of the password length, but it will
4728 * introduce a bit of extra uncertainty.
4730 * A few servers can't deal with SSH1_MSG_IGNORE, at
4731 * least in this context. For these servers, we need
4732 * an alternative defence. We make use of the fact
4733 * that the password is interpreted as a C string:
4734 * so we can append a NUL, then some random data.
4736 * A few servers can deal with neither SSH1_MSG_IGNORE
4737 * here _nor_ a padded password string.
4738 * For these servers we are left with no defences
4739 * against password length sniffing.
4741 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE) &&
4742 !(ssh->remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) {
4744 * The server can deal with SSH1_MSG_IGNORE, so
4745 * we can use the primary defence.
4747 int bottom, top, pwlen, i;
4750 pwlen = strlen(s->cur_prompt->prompts[0]->result);
4752 bottom = 0; /* zero length passwords are OK! :-) */
4755 bottom = pwlen & ~7;
4759 assert(pwlen >= bottom && pwlen <= top);
4761 randomstr = snewn(top + 1, char);
4763 for (i = bottom; i <= top; i++) {
4765 defer_packet(ssh, s->pwpkt_type,
4766 PKT_STR,s->cur_prompt->prompts[0]->result,
4769 for (j = 0; j < i; j++) {
4771 randomstr[j] = random_byte();
4772 } while (randomstr[j] == '\0');
4774 randomstr[i] = '\0';
4775 defer_packet(ssh, SSH1_MSG_IGNORE,
4776 PKT_STR, randomstr, PKT_END);
4779 logevent("Sending password with camouflage packets");
4780 ssh_pkt_defersend(ssh);
4783 else if (!(ssh->remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) {
4785 * The server can't deal with SSH1_MSG_IGNORE
4786 * but can deal with padded passwords, so we
4787 * can use the secondary defence.
4793 len = strlen(s->cur_prompt->prompts[0]->result);
4794 if (len < sizeof(string)) {
4796 strcpy(string, s->cur_prompt->prompts[0]->result);
4797 len++; /* cover the zero byte */
4798 while (len < sizeof(string)) {
4799 string[len++] = (char) random_byte();
4802 ss = s->cur_prompt->prompts[0]->result;
4804 logevent("Sending length-padded password");
4805 send_packet(ssh, s->pwpkt_type,
4806 PKT_INT, len, PKT_DATA, ss, len,
4810 * The server is believed unable to cope with
4811 * any of our password camouflage methods.
4814 len = strlen(s->cur_prompt->prompts[0]->result);
4815 logevent("Sending unpadded password");
4816 send_packet(ssh, s->pwpkt_type,
4818 PKT_DATA, s->cur_prompt->prompts[0]->result, len,
4822 send_packet(ssh, s->pwpkt_type,
4823 PKT_STR, s->cur_prompt->prompts[0]->result,
4826 logevent("Sent password");
4827 free_prompts(s->cur_prompt);
4829 if (pktin->type == SSH1_SMSG_FAILURE) {
4830 if (flags & FLAG_VERBOSE)
4831 c_write_str(ssh, "Access denied\r\n");
4832 logevent("Authentication refused");
4833 } else if (pktin->type != SSH1_SMSG_SUCCESS) {
4834 bombout(("Strange packet received, type %d", pktin->type));
4840 if (s->publickey_blob) {
4841 sfree(s->publickey_blob);
4842 sfree(s->publickey_comment);
4845 logevent("Authentication successful");
4850 static void ssh_channel_try_eof(struct ssh_channel *c)
4853 assert(c->pending_eof); /* precondition for calling us */
4855 return; /* can't close: not even opened yet */
4856 if (ssh->version == 2 && bufchain_size(&c->v.v2.outbuffer) > 0)
4857 return; /* can't send EOF: pending outgoing data */
4859 c->pending_eof = FALSE; /* we're about to send it */
4860 if (ssh->version == 1) {
4861 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid,
4863 c->closes |= CLOSES_SENT_EOF;
4865 struct Packet *pktout;
4866 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_EOF);
4867 ssh2_pkt_adduint32(pktout, c->remoteid);
4868 ssh2_pkt_send(ssh, pktout);
4869 c->closes |= CLOSES_SENT_EOF;
4870 ssh2_channel_check_close(c);
4874 Conf *sshfwd_get_conf(struct ssh_channel *c)
4880 void sshfwd_write_eof(struct ssh_channel *c)
4884 if (ssh->state == SSH_STATE_CLOSED)
4887 if (c->closes & CLOSES_SENT_EOF)
4890 c->pending_eof = TRUE;
4891 ssh_channel_try_eof(c);
4894 void sshfwd_unclean_close(struct ssh_channel *c, const char *err)
4898 if (ssh->state == SSH_STATE_CLOSED)
4903 x11_close(c->u.x11.xconn);
4904 logeventf(ssh, "Forwarded X11 connection terminated due to local "
4908 case CHAN_SOCKDATA_DORMANT:
4909 pfd_close(c->u.pfd.pf);
4910 logeventf(ssh, "Forwarded port closed due to local error: %s", err);
4913 c->type = CHAN_ZOMBIE;
4914 c->pending_eof = FALSE; /* this will confuse a zombie channel */
4916 ssh2_channel_check_close(c);
4919 int sshfwd_write(struct ssh_channel *c, char *buf, int len)
4923 if (ssh->state == SSH_STATE_CLOSED)
4926 if (ssh->version == 1) {
4927 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
4928 PKT_INT, c->remoteid,
4929 PKT_INT, len, PKT_DATA, buf, len,
4932 * In SSH-1 we can return 0 here - implying that forwarded
4933 * connections are never individually throttled - because
4934 * the only circumstance that can cause throttling will be
4935 * the whole SSH connection backing up, in which case
4936 * _everything_ will be throttled as a whole.
4940 ssh2_add_channel_data(c, buf, len);
4941 return ssh2_try_send(c);
4945 void sshfwd_unthrottle(struct ssh_channel *c, int bufsize)
4950 if (ssh->state == SSH_STATE_CLOSED)
4953 if (ssh->version == 1) {
4954 buflimit = SSH1_BUFFER_LIMIT;
4956 buflimit = c->v.v2.locmaxwin;
4957 ssh2_set_window(c, bufsize < buflimit ? buflimit - bufsize : 0);
4959 if (c->throttling_conn && bufsize <= buflimit) {
4960 c->throttling_conn = 0;
4961 ssh_throttle_conn(ssh, -1);
4965 static void ssh_queueing_handler(Ssh ssh, struct Packet *pktin)
4967 struct queued_handler *qh = ssh->qhead;
4971 assert(pktin->type == qh->msg1 || pktin->type == qh->msg2);
4974 assert(ssh->packet_dispatch[qh->msg1] == ssh_queueing_handler);
4975 ssh->packet_dispatch[qh->msg1] = ssh->q_saved_handler1;
4978 assert(ssh->packet_dispatch[qh->msg2] == ssh_queueing_handler);
4979 ssh->packet_dispatch[qh->msg2] = ssh->q_saved_handler2;
4983 ssh->qhead = qh->next;
4985 if (ssh->qhead->msg1 > 0) {
4986 ssh->q_saved_handler1 = ssh->packet_dispatch[ssh->qhead->msg1];
4987 ssh->packet_dispatch[ssh->qhead->msg1] = ssh_queueing_handler;
4989 if (ssh->qhead->msg2 > 0) {
4990 ssh->q_saved_handler2 = ssh->packet_dispatch[ssh->qhead->msg2];
4991 ssh->packet_dispatch[ssh->qhead->msg2] = ssh_queueing_handler;
4994 ssh->qhead = ssh->qtail = NULL;
4997 qh->handler(ssh, pktin, qh->ctx);
5002 static void ssh_queue_handler(Ssh ssh, int msg1, int msg2,
5003 chandler_fn_t handler, void *ctx)
5005 struct queued_handler *qh;
5007 qh = snew(struct queued_handler);
5010 qh->handler = handler;
5014 if (ssh->qtail == NULL) {
5018 ssh->q_saved_handler1 = ssh->packet_dispatch[ssh->qhead->msg1];
5019 ssh->packet_dispatch[qh->msg1] = ssh_queueing_handler;
5022 ssh->q_saved_handler2 = ssh->packet_dispatch[ssh->qhead->msg2];
5023 ssh->packet_dispatch[qh->msg2] = ssh_queueing_handler;
5026 ssh->qtail->next = qh;
5031 static void ssh_rportfwd_succfail(Ssh ssh, struct Packet *pktin, void *ctx)
5033 struct ssh_rportfwd *rpf, *pf = (struct ssh_rportfwd *)ctx;
5035 if (pktin->type == (ssh->version == 1 ? SSH1_SMSG_SUCCESS :
5036 SSH2_MSG_REQUEST_SUCCESS)) {
5037 logeventf(ssh, "Remote port forwarding from %s enabled",
5040 logeventf(ssh, "Remote port forwarding from %s refused",
5043 rpf = del234(ssh->rportfwds, pf);
5045 pf->pfrec->remote = NULL;
5050 int ssh_alloc_sharing_rportfwd(Ssh ssh, const char *shost, int sport,
5053 struct ssh_rportfwd *pf = snew(struct ssh_rportfwd);
5056 pf->share_ctx = share_ctx;
5057 pf->shost = dupstr(shost);
5059 pf->sportdesc = NULL;
5060 if (!ssh->rportfwds) {
5061 assert(ssh->version == 2);
5062 ssh->rportfwds = newtree234(ssh_rportcmp_ssh2);
5064 if (add234(ssh->rportfwds, pf) != pf) {
5072 static void ssh_sharing_global_request_response(Ssh ssh, struct Packet *pktin,
5075 share_got_pkt_from_server(ctx, pktin->type,
5076 pktin->body, pktin->length);
5079 void ssh_sharing_queue_global_request(Ssh ssh, void *share_ctx)
5081 ssh_queue_handler(ssh, SSH2_MSG_REQUEST_SUCCESS, SSH2_MSG_REQUEST_FAILURE,
5082 ssh_sharing_global_request_response, share_ctx);
5085 static void ssh_setup_portfwd(Ssh ssh, Conf *conf)
5087 struct ssh_portfwd *epf;
5091 if (!ssh->portfwds) {
5092 ssh->portfwds = newtree234(ssh_portcmp);
5095 * Go through the existing port forwardings and tag them
5096 * with status==DESTROY. Any that we want to keep will be
5097 * re-enabled (status==KEEP) as we go through the
5098 * configuration and find out which bits are the same as
5101 struct ssh_portfwd *epf;
5103 for (i = 0; (epf = index234(ssh->portfwds, i)) != NULL; i++)
5104 epf->status = DESTROY;
5107 for (val = conf_get_str_strs(conf, CONF_portfwd, NULL, &key);
5109 val = conf_get_str_strs(conf, CONF_portfwd, key, &key)) {
5110 char *kp, *kp2, *vp, *vp2;
5111 char address_family, type;
5112 int sport,dport,sserv,dserv;
5113 char *sports, *dports, *saddr, *host;
5117 address_family = 'A';
5119 if (*kp == 'A' || *kp == '4' || *kp == '6')
5120 address_family = *kp++;
5121 if (*kp == 'L' || *kp == 'R')
5124 if ((kp2 = host_strchr(kp, ':')) != NULL) {
5126 * There's a colon in the middle of the source port
5127 * string, which means that the part before it is
5128 * actually a source address.
5130 char *saddr_tmp = dupprintf("%.*s", (int)(kp2 - kp), kp);
5131 saddr = host_strduptrim(saddr_tmp);
5138 sport = atoi(sports);
5142 sport = net_service_lookup(sports);
5144 logeventf(ssh, "Service lookup failed for source"
5145 " port \"%s\"", sports);
5149 if (type == 'L' && !strcmp(val, "D")) {
5150 /* dynamic forwarding */
5157 /* ordinary forwarding */
5159 vp2 = vp + host_strcspn(vp, ":");
5160 host = dupprintf("%.*s", (int)(vp2 - vp), vp);
5164 dport = atoi(dports);
5168 dport = net_service_lookup(dports);
5170 logeventf(ssh, "Service lookup failed for destination"
5171 " port \"%s\"", dports);
5176 if (sport && dport) {
5177 /* Set up a description of the source port. */
5178 struct ssh_portfwd *pfrec, *epfrec;
5180 pfrec = snew(struct ssh_portfwd);
5182 pfrec->saddr = saddr;
5183 pfrec->sserv = sserv ? dupstr(sports) : NULL;
5184 pfrec->sport = sport;
5185 pfrec->daddr = host;
5186 pfrec->dserv = dserv ? dupstr(dports) : NULL;
5187 pfrec->dport = dport;
5188 pfrec->local = NULL;
5189 pfrec->remote = NULL;
5190 pfrec->addressfamily = (address_family == '4' ? ADDRTYPE_IPV4 :
5191 address_family == '6' ? ADDRTYPE_IPV6 :
5194 epfrec = add234(ssh->portfwds, pfrec);
5195 if (epfrec != pfrec) {
5196 if (epfrec->status == DESTROY) {
5198 * We already have a port forwarding up and running
5199 * with precisely these parameters. Hence, no need
5200 * to do anything; simply re-tag the existing one
5203 epfrec->status = KEEP;
5206 * Anything else indicates that there was a duplicate
5207 * in our input, which we'll silently ignore.
5209 free_portfwd(pfrec);
5211 pfrec->status = CREATE;
5220 * Now go through and destroy any port forwardings which were
5223 for (i = 0; (epf = index234(ssh->portfwds, i)) != NULL; i++)
5224 if (epf->status == DESTROY) {
5227 message = dupprintf("%s port forwarding from %s%s%d",
5228 epf->type == 'L' ? "local" :
5229 epf->type == 'R' ? "remote" : "dynamic",
5230 epf->saddr ? epf->saddr : "",
5231 epf->saddr ? ":" : "",
5234 if (epf->type != 'D') {
5235 char *msg2 = dupprintf("%s to %s:%d", message,
5236 epf->daddr, epf->dport);
5241 logeventf(ssh, "Cancelling %s", message);
5244 /* epf->remote or epf->local may be NULL if setting up a
5245 * forwarding failed. */
5247 struct ssh_rportfwd *rpf = epf->remote;
5248 struct Packet *pktout;
5251 * Cancel the port forwarding at the server
5254 if (ssh->version == 1) {
5256 * We cannot cancel listening ports on the
5257 * server side in SSH-1! There's no message
5258 * to support it. Instead, we simply remove
5259 * the rportfwd record from the local end
5260 * so that any connections the server tries
5261 * to make on it are rejected.
5264 pktout = ssh2_pkt_init(SSH2_MSG_GLOBAL_REQUEST);
5265 ssh2_pkt_addstring(pktout, "cancel-tcpip-forward");
5266 ssh2_pkt_addbool(pktout, 0);/* _don't_ want reply */
5268 ssh2_pkt_addstring(pktout, epf->saddr);
5269 } else if (conf_get_int(conf, CONF_rport_acceptall)) {
5270 /* XXX: rport_acceptall may not represent
5271 * what was used to open the original connection,
5272 * since it's reconfigurable. */
5273 ssh2_pkt_addstring(pktout, "");
5275 ssh2_pkt_addstring(pktout, "localhost");
5277 ssh2_pkt_adduint32(pktout, epf->sport);
5278 ssh2_pkt_send(ssh, pktout);
5281 del234(ssh->rportfwds, rpf);
5283 } else if (epf->local) {
5284 pfl_terminate(epf->local);
5287 delpos234(ssh->portfwds, i);
5289 i--; /* so we don't skip one in the list */
5293 * And finally, set up any new port forwardings (status==CREATE).
5295 for (i = 0; (epf = index234(ssh->portfwds, i)) != NULL; i++)
5296 if (epf->status == CREATE) {
5297 char *sportdesc, *dportdesc;
5298 sportdesc = dupprintf("%s%s%s%s%d%s",
5299 epf->saddr ? epf->saddr : "",
5300 epf->saddr ? ":" : "",
5301 epf->sserv ? epf->sserv : "",
5302 epf->sserv ? "(" : "",
5304 epf->sserv ? ")" : "");
5305 if (epf->type == 'D') {
5308 dportdesc = dupprintf("%s:%s%s%d%s",
5310 epf->dserv ? epf->dserv : "",
5311 epf->dserv ? "(" : "",
5313 epf->dserv ? ")" : "");
5316 if (epf->type == 'L') {
5317 char *err = pfl_listen(epf->daddr, epf->dport,
5318 epf->saddr, epf->sport,
5319 ssh, conf, &epf->local,
5320 epf->addressfamily);
5322 logeventf(ssh, "Local %sport %s forwarding to %s%s%s",
5323 epf->addressfamily == ADDRTYPE_IPV4 ? "IPv4 " :
5324 epf->addressfamily == ADDRTYPE_IPV6 ? "IPv6 " : "",
5325 sportdesc, dportdesc,
5326 err ? " failed: " : "", err ? err : "");
5329 } else if (epf->type == 'D') {
5330 char *err = pfl_listen(NULL, -1, epf->saddr, epf->sport,
5331 ssh, conf, &epf->local,
5332 epf->addressfamily);
5334 logeventf(ssh, "Local %sport %s SOCKS dynamic forwarding%s%s",
5335 epf->addressfamily == ADDRTYPE_IPV4 ? "IPv4 " :
5336 epf->addressfamily == ADDRTYPE_IPV6 ? "IPv6 " : "",
5338 err ? " failed: " : "", err ? err : "");
5343 struct ssh_rportfwd *pf;
5346 * Ensure the remote port forwardings tree exists.
5348 if (!ssh->rportfwds) {
5349 if (ssh->version == 1)
5350 ssh->rportfwds = newtree234(ssh_rportcmp_ssh1);
5352 ssh->rportfwds = newtree234(ssh_rportcmp_ssh2);
5355 pf = snew(struct ssh_rportfwd);
5356 pf->share_ctx = NULL;
5357 pf->dhost = dupstr(epf->daddr);
5358 pf->dport = epf->dport;
5360 pf->shost = dupstr(epf->saddr);
5361 } else if (conf_get_int(conf, CONF_rport_acceptall)) {
5362 pf->shost = dupstr("");
5364 pf->shost = dupstr("localhost");
5366 pf->sport = epf->sport;
5367 if (add234(ssh->rportfwds, pf) != pf) {
5368 logeventf(ssh, "Duplicate remote port forwarding to %s:%d",
5369 epf->daddr, epf->dport);
5372 logeventf(ssh, "Requesting remote port %s"
5373 " forward to %s", sportdesc, dportdesc);
5375 pf->sportdesc = sportdesc;
5380 if (ssh->version == 1) {
5381 send_packet(ssh, SSH1_CMSG_PORT_FORWARD_REQUEST,
5382 PKT_INT, epf->sport,
5383 PKT_STR, epf->daddr,
5384 PKT_INT, epf->dport,
5386 ssh_queue_handler(ssh, SSH1_SMSG_SUCCESS,
5388 ssh_rportfwd_succfail, pf);
5390 struct Packet *pktout;
5391 pktout = ssh2_pkt_init(SSH2_MSG_GLOBAL_REQUEST);
5392 ssh2_pkt_addstring(pktout, "tcpip-forward");
5393 ssh2_pkt_addbool(pktout, 1);/* want reply */
5394 ssh2_pkt_addstring(pktout, pf->shost);
5395 ssh2_pkt_adduint32(pktout, pf->sport);
5396 ssh2_pkt_send(ssh, pktout);
5398 ssh_queue_handler(ssh, SSH2_MSG_REQUEST_SUCCESS,
5399 SSH2_MSG_REQUEST_FAILURE,
5400 ssh_rportfwd_succfail, pf);
5409 static void ssh1_smsg_stdout_stderr_data(Ssh ssh, struct Packet *pktin)
5412 int stringlen, bufsize;
5414 ssh_pkt_getstring(pktin, &string, &stringlen);
5415 if (string == NULL) {
5416 bombout(("Incoming terminal data packet was badly formed"));
5420 bufsize = from_backend(ssh->frontend, pktin->type == SSH1_SMSG_STDERR_DATA,
5422 if (!ssh->v1_stdout_throttling && bufsize > SSH1_BUFFER_LIMIT) {
5423 ssh->v1_stdout_throttling = 1;
5424 ssh_throttle_conn(ssh, +1);
5428 static void ssh1_smsg_x11_open(Ssh ssh, struct Packet *pktin)
5430 /* Remote side is trying to open a channel to talk to our
5431 * X-Server. Give them back a local channel number. */
5432 struct ssh_channel *c;
5433 int remoteid = ssh_pkt_getuint32(pktin);
5435 logevent("Received X11 connect request");
5436 /* Refuse if X11 forwarding is disabled. */
5437 if (!ssh->X11_fwd_enabled) {
5438 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
5439 PKT_INT, remoteid, PKT_END);
5440 logevent("Rejected X11 connect request");
5442 c = snew(struct ssh_channel);
5445 c->u.x11.xconn = x11_init(ssh->x11authtree, c, NULL, -1);
5446 c->remoteid = remoteid;
5447 c->halfopen = FALSE;
5448 c->localid = alloc_channel_id(ssh);
5450 c->pending_eof = FALSE;
5451 c->throttling_conn = 0;
5452 c->type = CHAN_X11; /* identify channel type */
5453 add234(ssh->channels, c);
5454 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
5455 PKT_INT, c->remoteid, PKT_INT,
5456 c->localid, PKT_END);
5457 logevent("Opened X11 forward channel");
5461 static void ssh1_smsg_agent_open(Ssh ssh, struct Packet *pktin)
5463 /* Remote side is trying to open a channel to talk to our
5464 * agent. Give them back a local channel number. */
5465 struct ssh_channel *c;
5466 int remoteid = ssh_pkt_getuint32(pktin);
5468 /* Refuse if agent forwarding is disabled. */
5469 if (!ssh->agentfwd_enabled) {
5470 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
5471 PKT_INT, remoteid, PKT_END);
5473 c = snew(struct ssh_channel);
5475 c->remoteid = remoteid;
5476 c->halfopen = FALSE;
5477 c->localid = alloc_channel_id(ssh);
5479 c->pending_eof = FALSE;
5480 c->throttling_conn = 0;
5481 c->type = CHAN_AGENT; /* identify channel type */
5482 c->u.a.lensofar = 0;
5483 c->u.a.message = NULL;
5484 c->u.a.outstanding_requests = 0;
5485 add234(ssh->channels, c);
5486 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
5487 PKT_INT, c->remoteid, PKT_INT, c->localid,
5492 static void ssh1_msg_port_open(Ssh ssh, struct Packet *pktin)
5494 /* Remote side is trying to open a channel to talk to a
5495 * forwarded port. Give them back a local channel number. */
5496 struct ssh_rportfwd pf, *pfp;
5502 remoteid = ssh_pkt_getuint32(pktin);
5503 ssh_pkt_getstring(pktin, &host, &hostsize);
5504 port = ssh_pkt_getuint32(pktin);
5506 pf.dhost = dupprintf("%.*s", hostsize, host);
5508 pfp = find234(ssh->rportfwds, &pf, NULL);
5511 logeventf(ssh, "Rejected remote port open request for %s:%d",
5513 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
5514 PKT_INT, remoteid, PKT_END);
5516 struct ssh_channel *c = snew(struct ssh_channel);
5519 logeventf(ssh, "Received remote port open request for %s:%d",
5521 err = pfd_connect(&c->u.pfd.pf, pf.dhost, port,
5522 c, ssh->conf, pfp->pfrec->addressfamily);
5524 logeventf(ssh, "Port open failed: %s", err);
5527 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
5528 PKT_INT, remoteid, PKT_END);
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_SOCKDATA; /* identify channel type */
5537 add234(ssh->channels, c);
5538 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
5539 PKT_INT, c->remoteid, PKT_INT,
5540 c->localid, PKT_END);
5541 logevent("Forwarded port opened successfully");
5548 static void ssh1_msg_channel_open_confirmation(Ssh ssh, struct Packet *pktin)
5550 unsigned int remoteid = ssh_pkt_getuint32(pktin);
5551 unsigned int localid = ssh_pkt_getuint32(pktin);
5552 struct ssh_channel *c;
5554 c = find234(ssh->channels, &remoteid, ssh_channelfind);
5555 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
5556 c->remoteid = localid;
5557 c->halfopen = FALSE;
5558 c->type = CHAN_SOCKDATA;
5559 c->throttling_conn = 0;
5560 pfd_confirm(c->u.pfd.pf);
5563 if (c && c->pending_eof) {
5565 * We have a pending close on this channel,
5566 * which we decided on before the server acked
5567 * the channel open. So now we know the
5568 * remoteid, we can close it again.
5570 ssh_channel_try_eof(c);
5574 static void ssh1_msg_channel_open_failure(Ssh ssh, struct Packet *pktin)
5576 unsigned int remoteid = ssh_pkt_getuint32(pktin);
5577 struct ssh_channel *c;
5579 c = find234(ssh->channels, &remoteid, ssh_channelfind);
5580 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
5581 logevent("Forwarded connection refused by server");
5582 pfd_close(c->u.pfd.pf);
5583 del234(ssh->channels, c);
5588 static void ssh1_msg_channel_close(Ssh ssh, struct Packet *pktin)
5590 /* Remote side closes a channel. */
5591 unsigned i = ssh_pkt_getuint32(pktin);
5592 struct ssh_channel *c;
5593 c = find234(ssh->channels, &i, ssh_channelfind);
5594 if (c && !c->halfopen) {
5596 if (pktin->type == SSH1_MSG_CHANNEL_CLOSE &&
5597 !(c->closes & CLOSES_RCVD_EOF)) {
5599 * Received CHANNEL_CLOSE, which we translate into
5602 int send_close = FALSE;
5604 c->closes |= CLOSES_RCVD_EOF;
5609 x11_send_eof(c->u.x11.xconn);
5615 pfd_send_eof(c->u.pfd.pf);
5624 if (send_close && !(c->closes & CLOSES_SENT_EOF)) {
5625 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid,
5627 c->closes |= CLOSES_SENT_EOF;
5631 if (pktin->type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION &&
5632 !(c->closes & CLOSES_RCVD_CLOSE)) {
5634 if (!(c->closes & CLOSES_SENT_EOF)) {
5635 bombout(("Received CHANNEL_CLOSE_CONFIRMATION for channel %d"
5636 " for which we never sent CHANNEL_CLOSE\n", i));
5639 c->closes |= CLOSES_RCVD_CLOSE;
5642 if (!((CLOSES_SENT_EOF | CLOSES_RCVD_EOF) & ~c->closes) &&
5643 !(c->closes & CLOSES_SENT_CLOSE)) {
5644 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION,
5645 PKT_INT, c->remoteid, PKT_END);
5646 c->closes |= CLOSES_SENT_CLOSE;
5649 if (!((CLOSES_SENT_CLOSE | CLOSES_RCVD_CLOSE) & ~c->closes))
5650 ssh_channel_destroy(c);
5652 bombout(("Received CHANNEL_CLOSE%s for %s channel %d\n",
5653 pktin->type == SSH1_MSG_CHANNEL_CLOSE ? "" :
5654 "_CONFIRMATION", c ? "half-open" : "nonexistent",
5659 static void ssh1_msg_channel_data(Ssh ssh, struct Packet *pktin)
5661 /* Data sent down one of our channels. */
5662 int i = ssh_pkt_getuint32(pktin);
5665 struct ssh_channel *c;
5667 ssh_pkt_getstring(pktin, &p, &len);
5669 c = find234(ssh->channels, &i, ssh_channelfind);
5674 bufsize = x11_send(c->u.x11.xconn, p, len);
5677 bufsize = pfd_send(c->u.pfd.pf, p, len);
5680 /* Data for an agent message. Buffer it. */
5682 if (c->u.a.lensofar < 4) {
5683 unsigned int l = min(4 - c->u.a.lensofar, (unsigned)len);
5684 memcpy(c->u.a.msglen + c->u.a.lensofar, p,
5688 c->u.a.lensofar += l;
5690 if (c->u.a.lensofar == 4) {
5692 4 + GET_32BIT(c->u.a.msglen);
5693 c->u.a.message = snewn(c->u.a.totallen,
5695 memcpy(c->u.a.message, c->u.a.msglen, 4);
5697 if (c->u.a.lensofar >= 4 && len > 0) {
5699 min(c->u.a.totallen - c->u.a.lensofar,
5701 memcpy(c->u.a.message + c->u.a.lensofar, p,
5705 c->u.a.lensofar += l;
5707 if (c->u.a.lensofar == c->u.a.totallen) {
5710 c->u.a.outstanding_requests++;
5711 if (agent_query(c->u.a.message,
5714 ssh_agentf_callback, c))
5715 ssh_agentf_callback(c, reply, replylen);
5716 sfree(c->u.a.message);
5717 c->u.a.lensofar = 0;
5720 bufsize = 0; /* agent channels never back up */
5723 if (!c->throttling_conn && bufsize > SSH1_BUFFER_LIMIT) {
5724 c->throttling_conn = 1;
5725 ssh_throttle_conn(ssh, +1);
5730 static void ssh1_smsg_exit_status(Ssh ssh, struct Packet *pktin)
5732 ssh->exitcode = ssh_pkt_getuint32(pktin);
5733 logeventf(ssh, "Server sent command exit status %d", ssh->exitcode);
5734 send_packet(ssh, SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
5736 * In case `helpful' firewalls or proxies tack
5737 * extra human-readable text on the end of the
5738 * session which we might mistake for another
5739 * encrypted packet, we close the session once
5740 * we've sent EXIT_CONFIRMATION.
5742 ssh_disconnect(ssh, NULL, NULL, 0, TRUE);
5745 /* Helper function to deal with sending tty modes for REQUEST_PTY */
5746 static void ssh1_send_ttymode(void *data, char *mode, char *val)
5748 struct Packet *pktout = (struct Packet *)data;
5750 unsigned int arg = 0;
5751 while (strcmp(mode, ssh_ttymodes[i].mode) != 0) i++;
5752 if (i == lenof(ssh_ttymodes)) return;
5753 switch (ssh_ttymodes[i].type) {
5755 arg = ssh_tty_parse_specchar(val);
5758 arg = ssh_tty_parse_boolean(val);
5761 ssh2_pkt_addbyte(pktout, ssh_ttymodes[i].opcode);
5762 ssh2_pkt_addbyte(pktout, arg);
5765 int ssh_agent_forwarding_permitted(Ssh ssh)
5767 return conf_get_int(ssh->conf, CONF_agentfwd) && agent_exists();
5770 static void do_ssh1_connection(Ssh ssh, unsigned char *in, int inlen,
5771 struct Packet *pktin)
5773 crBegin(ssh->do_ssh1_connection_crstate);
5775 ssh->packet_dispatch[SSH1_SMSG_STDOUT_DATA] =
5776 ssh->packet_dispatch[SSH1_SMSG_STDERR_DATA] =
5777 ssh1_smsg_stdout_stderr_data;
5779 ssh->packet_dispatch[SSH1_MSG_CHANNEL_OPEN_CONFIRMATION] =
5780 ssh1_msg_channel_open_confirmation;
5781 ssh->packet_dispatch[SSH1_MSG_CHANNEL_OPEN_FAILURE] =
5782 ssh1_msg_channel_open_failure;
5783 ssh->packet_dispatch[SSH1_MSG_CHANNEL_CLOSE] =
5784 ssh->packet_dispatch[SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION] =
5785 ssh1_msg_channel_close;
5786 ssh->packet_dispatch[SSH1_MSG_CHANNEL_DATA] = ssh1_msg_channel_data;
5787 ssh->packet_dispatch[SSH1_SMSG_EXIT_STATUS] = ssh1_smsg_exit_status;
5789 if (ssh_agent_forwarding_permitted(ssh)) {
5790 logevent("Requesting agent forwarding");
5791 send_packet(ssh, SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END);
5795 if (pktin->type != SSH1_SMSG_SUCCESS
5796 && pktin->type != SSH1_SMSG_FAILURE) {
5797 bombout(("Protocol confusion"));
5799 } else if (pktin->type == SSH1_SMSG_FAILURE) {
5800 logevent("Agent forwarding refused");
5802 logevent("Agent forwarding enabled");
5803 ssh->agentfwd_enabled = TRUE;
5804 ssh->packet_dispatch[SSH1_SMSG_AGENT_OPEN] = ssh1_smsg_agent_open;
5808 if (conf_get_int(ssh->conf, CONF_x11_forward)) {
5810 x11_setup_display(conf_get_str(ssh->conf, CONF_x11_display),
5812 if (!ssh->x11disp) {
5813 /* FIXME: return an error message from x11_setup_display */
5814 logevent("X11 forwarding not enabled: unable to"
5815 " initialise X display");
5817 ssh->x11auth = x11_invent_fake_auth
5818 (ssh->x11authtree, conf_get_int(ssh->conf, CONF_x11_auth));
5819 ssh->x11auth->disp = ssh->x11disp;
5821 logevent("Requesting X11 forwarding");
5822 if (ssh->v1_local_protoflags & SSH1_PROTOFLAG_SCREEN_NUMBER) {
5823 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
5824 PKT_STR, ssh->x11auth->protoname,
5825 PKT_STR, ssh->x11auth->datastring,
5826 PKT_INT, ssh->x11disp->screennum,
5829 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
5830 PKT_STR, ssh->x11auth->protoname,
5831 PKT_STR, ssh->x11auth->datastring,
5837 if (pktin->type != SSH1_SMSG_SUCCESS
5838 && pktin->type != SSH1_SMSG_FAILURE) {
5839 bombout(("Protocol confusion"));
5841 } else if (pktin->type == SSH1_SMSG_FAILURE) {
5842 logevent("X11 forwarding refused");
5844 logevent("X11 forwarding enabled");
5845 ssh->X11_fwd_enabled = TRUE;
5846 ssh->packet_dispatch[SSH1_SMSG_X11_OPEN] = ssh1_smsg_x11_open;
5851 ssh_setup_portfwd(ssh, ssh->conf);
5852 ssh->packet_dispatch[SSH1_MSG_PORT_OPEN] = ssh1_msg_port_open;
5854 if (!conf_get_int(ssh->conf, CONF_nopty)) {
5856 /* Unpick the terminal-speed string. */
5857 /* XXX perhaps we should allow no speeds to be sent. */
5858 ssh->ospeed = 38400; ssh->ispeed = 38400; /* last-resort defaults */
5859 sscanf(conf_get_str(ssh->conf, CONF_termspeed), "%d,%d", &ssh->ospeed, &ssh->ispeed);
5860 /* Send the pty request. */
5861 pkt = ssh1_pkt_init(SSH1_CMSG_REQUEST_PTY);
5862 ssh_pkt_addstring(pkt, conf_get_str(ssh->conf, CONF_termtype));
5863 ssh_pkt_adduint32(pkt, ssh->term_height);
5864 ssh_pkt_adduint32(pkt, ssh->term_width);
5865 ssh_pkt_adduint32(pkt, 0); /* width in pixels */
5866 ssh_pkt_adduint32(pkt, 0); /* height in pixels */
5867 parse_ttymodes(ssh, ssh1_send_ttymode, (void *)pkt);
5868 ssh_pkt_addbyte(pkt, SSH1_TTY_OP_ISPEED);
5869 ssh_pkt_adduint32(pkt, ssh->ispeed);
5870 ssh_pkt_addbyte(pkt, SSH1_TTY_OP_OSPEED);
5871 ssh_pkt_adduint32(pkt, ssh->ospeed);
5872 ssh_pkt_addbyte(pkt, SSH_TTY_OP_END);
5874 ssh->state = SSH_STATE_INTERMED;
5878 if (pktin->type != SSH1_SMSG_SUCCESS
5879 && pktin->type != SSH1_SMSG_FAILURE) {
5880 bombout(("Protocol confusion"));
5882 } else if (pktin->type == SSH1_SMSG_FAILURE) {
5883 c_write_str(ssh, "Server refused to allocate pty\r\n");
5884 ssh->editing = ssh->echoing = 1;
5886 logeventf(ssh, "Allocated pty (ospeed %dbps, ispeed %dbps)",
5887 ssh->ospeed, ssh->ispeed);
5888 ssh->got_pty = TRUE;
5891 ssh->editing = ssh->echoing = 1;
5894 if (conf_get_int(ssh->conf, CONF_compression)) {
5895 send_packet(ssh, SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END);
5899 if (pktin->type != SSH1_SMSG_SUCCESS
5900 && pktin->type != SSH1_SMSG_FAILURE) {
5901 bombout(("Protocol confusion"));
5903 } else if (pktin->type == SSH1_SMSG_FAILURE) {
5904 c_write_str(ssh, "Server refused to compress\r\n");
5906 logevent("Started compression");
5907 ssh->v1_compressing = TRUE;
5908 ssh->cs_comp_ctx = zlib_compress_init();
5909 logevent("Initialised zlib (RFC1950) compression");
5910 ssh->sc_comp_ctx = zlib_decompress_init();
5911 logevent("Initialised zlib (RFC1950) decompression");
5915 * Start the shell or command.
5917 * Special case: if the first-choice command is an SSH-2
5918 * subsystem (hence not usable here) and the second choice
5919 * exists, we fall straight back to that.
5922 char *cmd = conf_get_str(ssh->conf, CONF_remote_cmd);
5924 if (conf_get_int(ssh->conf, CONF_ssh_subsys) &&
5925 conf_get_str(ssh->conf, CONF_remote_cmd2)) {
5926 cmd = conf_get_str(ssh->conf, CONF_remote_cmd2);
5927 ssh->fallback_cmd = TRUE;
5930 send_packet(ssh, SSH1_CMSG_EXEC_CMD, PKT_STR, cmd, PKT_END);
5932 send_packet(ssh, SSH1_CMSG_EXEC_SHELL, PKT_END);
5933 logevent("Started session");
5936 ssh->state = SSH_STATE_SESSION;
5937 if (ssh->size_needed)
5938 ssh_size(ssh, ssh->term_width, ssh->term_height);
5939 if (ssh->eof_needed)
5940 ssh_special(ssh, TS_EOF);
5943 ldisc_echoedit_update(ssh->ldisc); /* cause ldisc to notice changes */
5945 ssh->channels = newtree234(ssh_channelcmp);
5949 * By this point, most incoming packets are already being
5950 * handled by the dispatch table, and we need only pay
5951 * attention to the unusual ones.
5956 if (pktin->type == SSH1_SMSG_SUCCESS) {
5957 /* may be from EXEC_SHELL on some servers */
5958 } else if (pktin->type == SSH1_SMSG_FAILURE) {
5959 /* may be from EXEC_SHELL on some servers
5960 * if no pty is available or in other odd cases. Ignore */
5962 bombout(("Strange packet received: type %d", pktin->type));
5967 int len = min(inlen, 512);
5968 send_packet(ssh, SSH1_CMSG_STDIN_DATA,
5969 PKT_INT, len, PKT_DATA, in, len,
5981 * Handle the top-level SSH-2 protocol.
5983 static void ssh1_msg_debug(Ssh ssh, struct Packet *pktin)
5988 ssh_pkt_getstring(pktin, &msg, &msglen);
5989 logeventf(ssh, "Remote debug message: %.*s", msglen, msg);
5992 static void ssh1_msg_disconnect(Ssh ssh, struct Packet *pktin)
5994 /* log reason code in disconnect message */
5998 ssh_pkt_getstring(pktin, &msg, &msglen);
5999 bombout(("Server sent disconnect message:\n\"%.*s\"", msglen, msg));
6002 static void ssh_msg_ignore(Ssh ssh, struct Packet *pktin)
6004 /* Do nothing, because we're ignoring it! Duhh. */
6007 static void ssh1_protocol_setup(Ssh ssh)
6012 * Most messages are handled by the coroutines.
6014 for (i = 0; i < 256; i++)
6015 ssh->packet_dispatch[i] = NULL;
6018 * These special message types we install handlers for.
6020 ssh->packet_dispatch[SSH1_MSG_DISCONNECT] = ssh1_msg_disconnect;
6021 ssh->packet_dispatch[SSH1_MSG_IGNORE] = ssh_msg_ignore;
6022 ssh->packet_dispatch[SSH1_MSG_DEBUG] = ssh1_msg_debug;
6025 static void ssh1_protocol(Ssh ssh, void *vin, int inlen,
6026 struct Packet *pktin)
6028 unsigned char *in=(unsigned char*)vin;
6029 if (ssh->state == SSH_STATE_CLOSED)
6032 if (pktin && ssh->packet_dispatch[pktin->type]) {
6033 ssh->packet_dispatch[pktin->type](ssh, pktin);
6037 if (!ssh->protocol_initial_phase_done) {
6038 if (do_ssh1_login(ssh, in, inlen, pktin))
6039 ssh->protocol_initial_phase_done = TRUE;
6044 do_ssh1_connection(ssh, in, inlen, pktin);
6048 * Utility routine for decoding comma-separated strings in KEXINIT.
6050 static int in_commasep_string(char const *needle, char const *haystack,
6054 if (!needle || !haystack) /* protect against null pointers */
6056 needlen = strlen(needle);
6059 * Is it at the start of the string?
6061 if (haylen >= needlen && /* haystack is long enough */
6062 !memcmp(needle, haystack, needlen) && /* initial match */
6063 (haylen == needlen || haystack[needlen] == ',')
6064 /* either , or EOS follows */
6068 * If not, search for the next comma and resume after that.
6069 * If no comma found, terminate.
6071 while (haylen > 0 && *haystack != ',')
6072 haylen--, haystack++;
6075 haylen--, haystack++; /* skip over comma itself */
6080 * Similar routine for checking whether we have the first string in a list.
6082 static int first_in_commasep_string(char const *needle, char const *haystack,
6086 if (!needle || !haystack) /* protect against null pointers */
6088 needlen = strlen(needle);
6090 * Is it at the start of the string?
6092 if (haylen >= needlen && /* haystack is long enough */
6093 !memcmp(needle, haystack, needlen) && /* initial match */
6094 (haylen == needlen || haystack[needlen] == ',')
6095 /* either , or EOS follows */
6102 * Add a value to the comma-separated string at the end of the packet.
6103 * If the value is already in the string, don't bother adding it again.
6105 static void ssh2_pkt_addstring_commasep(struct Packet *pkt, const char *data)
6107 if (in_commasep_string(data, (char *)pkt->data + pkt->savedpos,
6108 pkt->length - pkt->savedpos)) return;
6109 if (pkt->length - pkt->savedpos > 0)
6110 ssh_pkt_addstring_str(pkt, ",");
6111 ssh_pkt_addstring_str(pkt, data);
6116 * SSH-2 key creation method.
6117 * (Currently assumes 2 lots of any hash are sufficient to generate
6118 * keys/IVs for any cipher/MAC. SSH2_MKKEY_ITERS documents this assumption.)
6120 #define SSH2_MKKEY_ITERS (2)
6121 static void ssh2_mkkey(Ssh ssh, Bignum K, unsigned char *H, char chr,
6122 unsigned char *keyspace)
6124 const struct ssh_hash *h = ssh->kex->hash;
6126 /* First hlen bytes. */
6128 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
6129 hash_mpint(h, s, K);
6130 h->bytes(s, H, h->hlen);
6131 h->bytes(s, &chr, 1);
6132 h->bytes(s, ssh->v2_session_id, ssh->v2_session_id_len);
6133 h->final(s, keyspace);
6134 /* Next hlen bytes. */
6136 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
6137 hash_mpint(h, s, K);
6138 h->bytes(s, H, h->hlen);
6139 h->bytes(s, keyspace, h->hlen);
6140 h->final(s, keyspace + h->hlen);
6144 * Handle the SSH-2 transport layer.
6146 static void do_ssh2_transport(Ssh ssh, void *vin, int inlen,
6147 struct Packet *pktin)
6149 unsigned char *in = (unsigned char *)vin;
6150 struct do_ssh2_transport_state {
6152 int nbits, pbits, warn_kex, warn_cscipher, warn_sccipher;
6153 Bignum p, g, e, f, K;
6156 int kex_init_value, kex_reply_value;
6157 const struct ssh_mac **maclist;
6159 const struct ssh2_cipher *cscipher_tobe;
6160 const struct ssh2_cipher *sccipher_tobe;
6161 const struct ssh_mac *csmac_tobe;
6162 const struct ssh_mac *scmac_tobe;
6163 int csmac_etm_tobe, scmac_etm_tobe;
6164 const struct ssh_compress *cscomp_tobe;
6165 const struct ssh_compress *sccomp_tobe;
6166 char *hostkeydata, *sigdata, *rsakeydata, *keystr, *fingerprint;
6167 int hostkeylen, siglen, rsakeylen;
6168 void *hkey; /* actual host key */
6169 void *rsakey; /* for RSA kex */
6170 void *eckey; /* for ECDH kex */
6171 unsigned char exchange_hash[SSH2_KEX_MAX_HASH_LEN];
6172 int n_preferred_kex;
6173 const struct ssh_kexes *preferred_kex[KEX_MAX];
6174 int n_preferred_ciphers;
6175 const struct ssh2_ciphers *preferred_ciphers[CIPHER_MAX];
6176 const struct ssh_compress *preferred_comp;
6177 int userauth_succeeded; /* for delayed compression */
6178 int pending_compression;
6179 int got_session_id, activated_authconn;
6180 struct Packet *pktout;
6185 crState(do_ssh2_transport_state);
6187 assert(!ssh->bare_connection);
6191 s->cscipher_tobe = s->sccipher_tobe = NULL;
6192 s->csmac_tobe = s->scmac_tobe = NULL;
6193 s->cscomp_tobe = s->sccomp_tobe = NULL;
6195 s->got_session_id = s->activated_authconn = FALSE;
6196 s->userauth_succeeded = FALSE;
6197 s->pending_compression = FALSE;
6200 * Be prepared to work around the buggy MAC problem.
6202 if (ssh->remote_bugs & BUG_SSH2_HMAC)
6203 s->maclist = buggymacs, s->nmacs = lenof(buggymacs);
6205 s->maclist = macs, s->nmacs = lenof(macs);
6208 ssh->pkt_kctx = SSH2_PKTCTX_NOKEX;
6213 * Set up the preferred key exchange. (NULL => warn below here)
6215 s->n_preferred_kex = 0;
6216 for (i = 0; i < KEX_MAX; i++) {
6217 switch (conf_get_int_int(ssh->conf, CONF_ssh_kexlist, i)) {
6219 s->preferred_kex[s->n_preferred_kex++] =
6220 &ssh_diffiehellman_gex;
6223 s->preferred_kex[s->n_preferred_kex++] =
6224 &ssh_diffiehellman_group14;
6227 s->preferred_kex[s->n_preferred_kex++] =
6228 &ssh_diffiehellman_group1;
6231 s->preferred_kex[s->n_preferred_kex++] =
6235 s->preferred_kex[s->n_preferred_kex++] =
6239 /* Flag for later. Don't bother if it's the last in
6241 if (i < KEX_MAX - 1) {
6242 s->preferred_kex[s->n_preferred_kex++] = NULL;
6249 * Set up the preferred ciphers. (NULL => warn below here)
6251 s->n_preferred_ciphers = 0;
6252 for (i = 0; i < CIPHER_MAX; i++) {
6253 switch (conf_get_int_int(ssh->conf, CONF_ssh_cipherlist, i)) {
6254 case CIPHER_BLOWFISH:
6255 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_blowfish;
6258 if (conf_get_int(ssh->conf, CONF_ssh2_des_cbc)) {
6259 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_des;
6263 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_3des;
6266 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_aes;
6268 case CIPHER_ARCFOUR:
6269 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_arcfour;
6272 /* Flag for later. Don't bother if it's the last in
6274 if (i < CIPHER_MAX - 1) {
6275 s->preferred_ciphers[s->n_preferred_ciphers++] = NULL;
6282 * Set up preferred compression.
6284 if (conf_get_int(ssh->conf, CONF_compression))
6285 s->preferred_comp = &ssh_zlib;
6287 s->preferred_comp = &ssh_comp_none;
6290 * Enable queueing of outgoing auth- or connection-layer
6291 * packets while we are in the middle of a key exchange.
6293 ssh->queueing = TRUE;
6296 * Flag that KEX is in progress.
6298 ssh->kex_in_progress = TRUE;
6301 * Construct and send our key exchange packet.
6303 s->pktout = ssh2_pkt_init(SSH2_MSG_KEXINIT);
6304 for (i = 0; i < 16; i++)
6305 ssh2_pkt_addbyte(s->pktout, (unsigned char) random_byte());
6306 /* List key exchange algorithms. */
6307 ssh2_pkt_addstring_start(s->pktout);
6308 for (i = 0; i < s->n_preferred_kex; i++) {
6309 const struct ssh_kexes *k = s->preferred_kex[i];
6310 if (!k) continue; /* warning flag */
6311 for (j = 0; j < k->nkexes; j++)
6312 ssh2_pkt_addstring_commasep(s->pktout, k->list[j]->name);
6314 /* List server host key algorithms. */
6315 if (!s->got_session_id) {
6317 * In the first key exchange, we list all the algorithms
6318 * we're prepared to cope with.
6320 ssh2_pkt_addstring_start(s->pktout);
6321 for (i = 0; i < lenof(hostkey_algs); i++)
6322 ssh2_pkt_addstring_commasep(s->pktout, hostkey_algs[i]->name);
6325 * In subsequent key exchanges, we list only the kex
6326 * algorithm that was selected in the first key exchange,
6327 * so that we keep getting the same host key and hence
6328 * don't have to interrupt the user's session to ask for
6332 ssh2_pkt_addstring(s->pktout, ssh->hostkey->name);
6334 /* List encryption algorithms (client->server then server->client). */
6335 for (k = 0; k < 2; k++) {
6336 ssh2_pkt_addstring_start(s->pktout);
6337 for (i = 0; i < s->n_preferred_ciphers; i++) {
6338 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
6339 if (!c) continue; /* warning flag */
6340 for (j = 0; j < c->nciphers; j++)
6341 ssh2_pkt_addstring_commasep(s->pktout, c->list[j]->name);
6344 /* List MAC algorithms (client->server then server->client). */
6345 for (j = 0; j < 2; j++) {
6346 ssh2_pkt_addstring_start(s->pktout);
6347 for (i = 0; i < s->nmacs; i++) {
6348 ssh2_pkt_addstring_commasep(s->pktout, s->maclist[i]->name);
6350 for (i = 0; i < s->nmacs; i++) {
6351 /* For each MAC, there may also be an ETM version,
6352 * which we list second. */
6353 if (s->maclist[i]->etm_name)
6354 ssh2_pkt_addstring_commasep(s->pktout, s->maclist[i]->etm_name);
6357 /* List client->server compression algorithms,
6358 * then server->client compression algorithms. (We use the
6359 * same set twice.) */
6360 for (j = 0; j < 2; j++) {
6361 ssh2_pkt_addstring_start(s->pktout);
6362 assert(lenof(compressions) > 1);
6363 /* Prefer non-delayed versions */
6364 ssh2_pkt_addstring_commasep(s->pktout, s->preferred_comp->name);
6365 /* We don't even list delayed versions of algorithms until
6366 * they're allowed to be used, to avoid a race. See the end of
6368 if (s->userauth_succeeded && s->preferred_comp->delayed_name)
6369 ssh2_pkt_addstring_commasep(s->pktout,
6370 s->preferred_comp->delayed_name);
6371 for (i = 0; i < lenof(compressions); i++) {
6372 const struct ssh_compress *c = compressions[i];
6373 ssh2_pkt_addstring_commasep(s->pktout, c->name);
6374 if (s->userauth_succeeded && c->delayed_name)
6375 ssh2_pkt_addstring_commasep(s->pktout, c->delayed_name);
6378 /* List client->server languages. Empty list. */
6379 ssh2_pkt_addstring_start(s->pktout);
6380 /* List server->client languages. Empty list. */
6381 ssh2_pkt_addstring_start(s->pktout);
6382 /* First KEX packet does _not_ follow, because we're not that brave. */
6383 ssh2_pkt_addbool(s->pktout, FALSE);
6385 ssh2_pkt_adduint32(s->pktout, 0);
6388 s->our_kexinitlen = s->pktout->length - 5;
6389 s->our_kexinit = snewn(s->our_kexinitlen, unsigned char);
6390 memcpy(s->our_kexinit, s->pktout->data + 5, s->our_kexinitlen);
6392 ssh2_pkt_send_noqueue(ssh, s->pktout);
6395 crWaitUntilV(pktin);
6398 * Now examine the other side's KEXINIT to see what we're up
6402 char *str, *preferred;
6405 if (pktin->type != SSH2_MSG_KEXINIT) {
6406 bombout(("expected key exchange packet from server"));
6410 ssh->hostkey = NULL;
6411 s->cscipher_tobe = NULL;
6412 s->sccipher_tobe = NULL;
6413 s->csmac_tobe = NULL;
6414 s->scmac_tobe = NULL;
6415 s->cscomp_tobe = NULL;
6416 s->sccomp_tobe = NULL;
6417 s->warn_kex = s->warn_cscipher = s->warn_sccipher = FALSE;
6419 pktin->savedpos += 16; /* skip garbage cookie */
6420 ssh_pkt_getstring(pktin, &str, &len); /* key exchange algorithms */
6422 bombout(("KEXINIT packet was incomplete"));
6427 for (i = 0; i < s->n_preferred_kex; i++) {
6428 const struct ssh_kexes *k = s->preferred_kex[i];
6432 for (j = 0; j < k->nkexes; j++) {
6433 if (!preferred) preferred = k->list[j]->name;
6434 if (in_commasep_string(k->list[j]->name, str, len)) {
6435 ssh->kex = k->list[j];
6444 bombout(("Couldn't agree a key exchange algorithm"
6445 " (available: %.*s)", len, str));
6449 * Note that the server's guess is considered wrong if it doesn't match
6450 * the first algorithm in our list, even if it's still the algorithm
6453 s->guessok = first_in_commasep_string(preferred, str, len);
6454 ssh_pkt_getstring(pktin, &str, &len); /* host key algorithms */
6456 bombout(("KEXINIT packet was incomplete"));
6459 for (i = 0; i < lenof(hostkey_algs); i++) {
6460 if (in_commasep_string(hostkey_algs[i]->name, str, len)) {
6461 ssh->hostkey = hostkey_algs[i];
6465 if (!ssh->hostkey) {
6466 bombout(("Couldn't agree a host key algorithm"
6467 " (available: %.*s)", len, str));
6471 s->guessok = s->guessok &&
6472 first_in_commasep_string(hostkey_algs[0]->name, str, len);
6473 ssh_pkt_getstring(pktin, &str, &len); /* client->server cipher */
6475 bombout(("KEXINIT packet was incomplete"));
6478 for (i = 0; i < s->n_preferred_ciphers; i++) {
6479 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
6481 s->warn_cscipher = TRUE;
6483 for (j = 0; j < c->nciphers; j++) {
6484 if (in_commasep_string(c->list[j]->name, str, len)) {
6485 s->cscipher_tobe = c->list[j];
6490 if (s->cscipher_tobe)
6493 if (!s->cscipher_tobe) {
6494 bombout(("Couldn't agree a client-to-server cipher"
6495 " (available: %.*s)", len, str));
6499 ssh_pkt_getstring(pktin, &str, &len); /* server->client cipher */
6501 bombout(("KEXINIT packet was incomplete"));
6504 for (i = 0; i < s->n_preferred_ciphers; i++) {
6505 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
6507 s->warn_sccipher = TRUE;
6509 for (j = 0; j < c->nciphers; j++) {
6510 if (in_commasep_string(c->list[j]->name, str, len)) {
6511 s->sccipher_tobe = c->list[j];
6516 if (s->sccipher_tobe)
6519 if (!s->sccipher_tobe) {
6520 bombout(("Couldn't agree a server-to-client cipher"
6521 " (available: %.*s)", len, str));
6525 ssh_pkt_getstring(pktin, &str, &len); /* client->server mac */
6527 bombout(("KEXINIT packet was incomplete"));
6530 for (i = 0; i < s->nmacs; i++) {
6531 if (in_commasep_string(s->maclist[i]->name, str, len)) {
6532 s->csmac_tobe = s->maclist[i];
6533 s->csmac_etm_tobe = FALSE;
6537 if (!s->csmac_tobe) {
6538 for (i = 0; i < s->nmacs; i++) {
6539 if (s->maclist[i]->etm_name &&
6540 in_commasep_string(s->maclist[i]->etm_name, str, len)) {
6541 s->csmac_tobe = s->maclist[i];
6542 s->csmac_etm_tobe = TRUE;
6547 if (!s->csmac_tobe) {
6548 bombout(("Couldn't agree a client-to-server MAC"
6549 " (available: %.*s)", len, str));
6552 ssh_pkt_getstring(pktin, &str, &len); /* server->client mac */
6554 bombout(("KEXINIT packet was incomplete"));
6557 for (i = 0; i < s->nmacs; i++) {
6558 if (in_commasep_string(s->maclist[i]->name, str, len)) {
6559 s->scmac_tobe = s->maclist[i];
6560 s->scmac_etm_tobe = FALSE;
6564 if (!s->scmac_tobe) {
6565 for (i = 0; i < s->nmacs; i++) {
6566 if (s->maclist[i]->etm_name &&
6567 in_commasep_string(s->maclist[i]->etm_name, str, len)) {
6568 s->scmac_tobe = s->maclist[i];
6569 s->scmac_etm_tobe = TRUE;
6574 if (!s->scmac_tobe) {
6575 bombout(("Couldn't agree a server-to-client MAC"
6576 " (available: %.*s)", len, str));
6579 ssh_pkt_getstring(pktin, &str, &len); /* client->server compression */
6581 bombout(("KEXINIT packet was incomplete"));
6584 for (i = 0; i < lenof(compressions) + 1; i++) {
6585 const struct ssh_compress *c =
6586 i == 0 ? s->preferred_comp : compressions[i - 1];
6587 if (in_commasep_string(c->name, str, len)) {
6590 } else if (in_commasep_string(c->delayed_name, str, len)) {
6591 if (s->userauth_succeeded) {
6595 s->pending_compression = TRUE; /* try this later */
6599 ssh_pkt_getstring(pktin, &str, &len); /* server->client compression */
6601 bombout(("KEXINIT packet was incomplete"));
6604 for (i = 0; i < lenof(compressions) + 1; i++) {
6605 const struct ssh_compress *c =
6606 i == 0 ? s->preferred_comp : compressions[i - 1];
6607 if (in_commasep_string(c->name, str, len)) {
6610 } else if (in_commasep_string(c->delayed_name, str, len)) {
6611 if (s->userauth_succeeded) {
6615 s->pending_compression = TRUE; /* try this later */
6619 if (s->pending_compression) {
6620 logevent("Server supports delayed compression; "
6621 "will try this later");
6623 ssh_pkt_getstring(pktin, &str, &len); /* client->server language */
6624 ssh_pkt_getstring(pktin, &str, &len); /* server->client language */
6625 s->ignorepkt = ssh2_pkt_getbool(pktin) && !s->guessok;
6627 ssh->exhash = ssh->kex->hash->init();
6628 hash_string(ssh->kex->hash, ssh->exhash, ssh->v_c, strlen(ssh->v_c));
6629 hash_string(ssh->kex->hash, ssh->exhash, ssh->v_s, strlen(ssh->v_s));
6630 hash_string(ssh->kex->hash, ssh->exhash,
6631 s->our_kexinit, s->our_kexinitlen);
6632 sfree(s->our_kexinit);
6633 /* Include the type byte in the hash of server's KEXINIT */
6634 hash_string(ssh->kex->hash, ssh->exhash,
6635 pktin->body - 1, pktin->length + 1);
6638 ssh_set_frozen(ssh, 1);
6639 s->dlgret = askalg(ssh->frontend, "key-exchange algorithm",
6641 ssh_dialog_callback, ssh);
6642 if (s->dlgret < 0) {
6646 bombout(("Unexpected data from server while"
6647 " waiting for user response"));
6650 } while (pktin || inlen > 0);
6651 s->dlgret = ssh->user_response;
6653 ssh_set_frozen(ssh, 0);
6654 if (s->dlgret == 0) {
6655 ssh_disconnect(ssh, "User aborted at kex warning", NULL,
6661 if (s->warn_cscipher) {
6662 ssh_set_frozen(ssh, 1);
6663 s->dlgret = askalg(ssh->frontend,
6664 "client-to-server cipher",
6665 s->cscipher_tobe->name,
6666 ssh_dialog_callback, ssh);
6667 if (s->dlgret < 0) {
6671 bombout(("Unexpected data from server while"
6672 " waiting for user response"));
6675 } while (pktin || inlen > 0);
6676 s->dlgret = ssh->user_response;
6678 ssh_set_frozen(ssh, 0);
6679 if (s->dlgret == 0) {
6680 ssh_disconnect(ssh, "User aborted at cipher warning", NULL,
6686 if (s->warn_sccipher) {
6687 ssh_set_frozen(ssh, 1);
6688 s->dlgret = askalg(ssh->frontend,
6689 "server-to-client cipher",
6690 s->sccipher_tobe->name,
6691 ssh_dialog_callback, ssh);
6692 if (s->dlgret < 0) {
6696 bombout(("Unexpected data from server while"
6697 " waiting for user response"));
6700 } while (pktin || inlen > 0);
6701 s->dlgret = ssh->user_response;
6703 ssh_set_frozen(ssh, 0);
6704 if (s->dlgret == 0) {
6705 ssh_disconnect(ssh, "User aborted at cipher warning", NULL,
6711 if (s->ignorepkt) /* first_kex_packet_follows */
6712 crWaitUntilV(pktin); /* Ignore packet */
6715 if (ssh->kex->main_type == KEXTYPE_DH) {
6717 * Work out the number of bits of key we will need from the
6718 * key exchange. We start with the maximum key length of
6724 csbits = s->cscipher_tobe->keylen;
6725 scbits = s->sccipher_tobe->keylen;
6726 s->nbits = (csbits > scbits ? csbits : scbits);
6728 /* The keys only have hlen-bit entropy, since they're based on
6729 * a hash. So cap the key size at hlen bits. */
6730 if (s->nbits > ssh->kex->hash->hlen * 8)
6731 s->nbits = ssh->kex->hash->hlen * 8;
6734 * If we're doing Diffie-Hellman group exchange, start by
6735 * requesting a group.
6737 if (!ssh->kex->pdata) {
6738 logevent("Doing Diffie-Hellman group exchange");
6739 ssh->pkt_kctx = SSH2_PKTCTX_DHGEX;
6741 * Work out how big a DH group we will need to allow that
6744 s->pbits = 512 << ((s->nbits - 1) / 64);
6745 if (s->pbits < DH_MIN_SIZE)
6746 s->pbits = DH_MIN_SIZE;
6747 if (s->pbits > DH_MAX_SIZE)
6748 s->pbits = DH_MAX_SIZE;
6749 if ((ssh->remote_bugs & BUG_SSH2_OLDGEX)) {
6750 s->pktout = ssh2_pkt_init(SSH2_MSG_KEX_DH_GEX_REQUEST_OLD);
6751 ssh2_pkt_adduint32(s->pktout, s->pbits);
6753 s->pktout = ssh2_pkt_init(SSH2_MSG_KEX_DH_GEX_REQUEST);
6754 ssh2_pkt_adduint32(s->pktout, DH_MIN_SIZE);
6755 ssh2_pkt_adduint32(s->pktout, s->pbits);
6756 ssh2_pkt_adduint32(s->pktout, DH_MAX_SIZE);
6758 ssh2_pkt_send_noqueue(ssh, s->pktout);
6760 crWaitUntilV(pktin);
6761 if (pktin->type != SSH2_MSG_KEX_DH_GEX_GROUP) {
6762 bombout(("expected key exchange group packet from server"));
6765 s->p = ssh2_pkt_getmp(pktin);
6766 s->g = ssh2_pkt_getmp(pktin);
6767 if (!s->p || !s->g) {
6768 bombout(("unable to read mp-ints from incoming group packet"));
6771 ssh->kex_ctx = dh_setup_gex(s->p, s->g);
6772 s->kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT;
6773 s->kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY;
6775 ssh->pkt_kctx = SSH2_PKTCTX_DHGROUP;
6776 ssh->kex_ctx = dh_setup_group(ssh->kex);
6777 s->kex_init_value = SSH2_MSG_KEXDH_INIT;
6778 s->kex_reply_value = SSH2_MSG_KEXDH_REPLY;
6779 logeventf(ssh, "Using Diffie-Hellman with standard group \"%s\"",
6780 ssh->kex->groupname);
6783 logeventf(ssh, "Doing Diffie-Hellman key exchange with hash %s",
6784 ssh->kex->hash->text_name);
6786 * Now generate and send e for Diffie-Hellman.
6788 set_busy_status(ssh->frontend, BUSY_CPU); /* this can take a while */
6789 s->e = dh_create_e(ssh->kex_ctx, s->nbits * 2);
6790 s->pktout = ssh2_pkt_init(s->kex_init_value);
6791 ssh2_pkt_addmp(s->pktout, s->e);
6792 ssh2_pkt_send_noqueue(ssh, s->pktout);
6794 set_busy_status(ssh->frontend, BUSY_WAITING); /* wait for server */
6795 crWaitUntilV(pktin);
6796 if (pktin->type != s->kex_reply_value) {
6797 bombout(("expected key exchange reply packet from server"));
6800 set_busy_status(ssh->frontend, BUSY_CPU); /* cogitate */
6801 ssh_pkt_getstring(pktin, &s->hostkeydata, &s->hostkeylen);
6802 s->hkey = ssh->hostkey->newkey(s->hostkeydata, s->hostkeylen);
6803 s->f = ssh2_pkt_getmp(pktin);
6805 bombout(("unable to parse key exchange reply packet"));
6808 ssh_pkt_getstring(pktin, &s->sigdata, &s->siglen);
6811 const char *err = dh_validate_f(ssh->kex_ctx, s->f);
6813 bombout(("key exchange reply failed validation: %s", err));
6817 s->K = dh_find_K(ssh->kex_ctx, s->f);
6819 /* We assume everything from now on will be quick, and it might
6820 * involve user interaction. */
6821 set_busy_status(ssh->frontend, BUSY_NOT);
6823 hash_string(ssh->kex->hash, ssh->exhash, s->hostkeydata, s->hostkeylen);
6824 if (!ssh->kex->pdata) {
6825 if (!(ssh->remote_bugs & BUG_SSH2_OLDGEX))
6826 hash_uint32(ssh->kex->hash, ssh->exhash, DH_MIN_SIZE);
6827 hash_uint32(ssh->kex->hash, ssh->exhash, s->pbits);
6828 if (!(ssh->remote_bugs & BUG_SSH2_OLDGEX))
6829 hash_uint32(ssh->kex->hash, ssh->exhash, DH_MAX_SIZE);
6830 hash_mpint(ssh->kex->hash, ssh->exhash, s->p);
6831 hash_mpint(ssh->kex->hash, ssh->exhash, s->g);
6833 hash_mpint(ssh->kex->hash, ssh->exhash, s->e);
6834 hash_mpint(ssh->kex->hash, ssh->exhash, s->f);
6836 dh_cleanup(ssh->kex_ctx);
6838 if (!ssh->kex->pdata) {
6842 } else if (ssh->kex->main_type == KEXTYPE_ECDH) {
6844 logeventf(ssh, "Doing ECDH key exchange with hash %s",
6845 ssh->kex->hash->text_name);
6846 ssh->pkt_kctx = SSH2_PKTCTX_ECDHKEX;
6848 s->eckey = ssh_ecdhkex_newkey(ssh->kex->name);
6850 bombout(("Unable to generate key for ECDH"));
6856 int publicPointLength;
6857 publicPoint = ssh_ecdhkex_getpublic(s->eckey, &publicPointLength);
6859 ssh_ecdhkex_freekey(s->eckey);
6860 bombout(("Unable to encode public key for ECDH"));
6863 s->pktout = ssh2_pkt_init(SSH2_MSG_KEX_ECDH_INIT);
6864 ssh2_pkt_addstring_start(s->pktout);
6865 ssh2_pkt_addstring_data(s->pktout, publicPoint, publicPointLength);
6869 ssh2_pkt_send_noqueue(ssh, s->pktout);
6871 crWaitUntilV(pktin);
6872 if (pktin->type != SSH2_MSG_KEX_ECDH_REPLY) {
6873 ssh_ecdhkex_freekey(s->eckey);
6874 bombout(("expected ECDH reply packet from server"));
6878 ssh_pkt_getstring(pktin, &s->hostkeydata, &s->hostkeylen);
6879 hash_string(ssh->kex->hash, ssh->exhash, s->hostkeydata, s->hostkeylen);
6880 s->hkey = ssh->hostkey->newkey(s->hostkeydata, s->hostkeylen);
6884 int publicPointLength;
6885 publicPoint = ssh_ecdhkex_getpublic(s->eckey, &publicPointLength);
6887 ssh_ecdhkex_freekey(s->eckey);
6888 bombout(("Unable to encode public key for ECDH hash"));
6891 hash_string(ssh->kex->hash, ssh->exhash,
6892 publicPoint, publicPointLength);
6899 ssh_pkt_getstring(pktin, &keydata, &keylen);
6900 hash_string(ssh->kex->hash, ssh->exhash, keydata, keylen);
6901 s->K = ssh_ecdhkex_getkey(s->eckey, keydata, keylen);
6903 ssh_ecdhkex_freekey(s->eckey);
6904 bombout(("point received in ECDH was not valid"));
6909 ssh_pkt_getstring(pktin, &s->sigdata, &s->siglen);
6911 ssh_ecdhkex_freekey(s->eckey);
6913 logeventf(ssh, "Doing RSA key exchange with hash %s",
6914 ssh->kex->hash->text_name);
6915 ssh->pkt_kctx = SSH2_PKTCTX_RSAKEX;
6917 * RSA key exchange. First expect a KEXRSA_PUBKEY packet
6920 crWaitUntilV(pktin);
6921 if (pktin->type != SSH2_MSG_KEXRSA_PUBKEY) {
6922 bombout(("expected RSA public key packet from server"));
6926 ssh_pkt_getstring(pktin, &s->hostkeydata, &s->hostkeylen);
6927 hash_string(ssh->kex->hash, ssh->exhash,
6928 s->hostkeydata, s->hostkeylen);
6929 s->hkey = ssh->hostkey->newkey(s->hostkeydata, s->hostkeylen);
6933 ssh_pkt_getstring(pktin, &keydata, &s->rsakeylen);
6934 s->rsakeydata = snewn(s->rsakeylen, char);
6935 memcpy(s->rsakeydata, keydata, s->rsakeylen);
6938 s->rsakey = ssh_rsakex_newkey(s->rsakeydata, s->rsakeylen);
6940 sfree(s->rsakeydata);
6941 bombout(("unable to parse RSA public key from server"));
6945 hash_string(ssh->kex->hash, ssh->exhash, s->rsakeydata, s->rsakeylen);
6948 * Next, set up a shared secret K, of precisely KLEN -
6949 * 2*HLEN - 49 bits, where KLEN is the bit length of the
6950 * RSA key modulus and HLEN is the bit length of the hash
6954 int klen = ssh_rsakex_klen(s->rsakey);
6955 int nbits = klen - (2*ssh->kex->hash->hlen*8 + 49);
6957 unsigned char *kstr1, *kstr2, *outstr;
6958 int kstr1len, kstr2len, outstrlen;
6960 s->K = bn_power_2(nbits - 1);
6962 for (i = 0; i < nbits; i++) {
6964 byte = random_byte();
6966 bignum_set_bit(s->K, i, (byte >> (i & 7)) & 1);
6970 * Encode this as an mpint.
6972 kstr1 = ssh2_mpint_fmt(s->K, &kstr1len);
6973 kstr2 = snewn(kstr2len = 4 + kstr1len, unsigned char);
6974 PUT_32BIT(kstr2, kstr1len);
6975 memcpy(kstr2 + 4, kstr1, kstr1len);
6978 * Encrypt it with the given RSA key.
6980 outstrlen = (klen + 7) / 8;
6981 outstr = snewn(outstrlen, unsigned char);
6982 ssh_rsakex_encrypt(ssh->kex->hash, kstr2, kstr2len,
6983 outstr, outstrlen, s->rsakey);
6986 * And send it off in a return packet.
6988 s->pktout = ssh2_pkt_init(SSH2_MSG_KEXRSA_SECRET);
6989 ssh2_pkt_addstring_start(s->pktout);
6990 ssh2_pkt_addstring_data(s->pktout, (char *)outstr, outstrlen);
6991 ssh2_pkt_send_noqueue(ssh, s->pktout);
6993 hash_string(ssh->kex->hash, ssh->exhash, outstr, outstrlen);
7000 ssh_rsakex_freekey(s->rsakey);
7002 crWaitUntilV(pktin);
7003 if (pktin->type != SSH2_MSG_KEXRSA_DONE) {
7004 sfree(s->rsakeydata);
7005 bombout(("expected signature packet from server"));
7009 ssh_pkt_getstring(pktin, &s->sigdata, &s->siglen);
7011 sfree(s->rsakeydata);
7014 hash_mpint(ssh->kex->hash, ssh->exhash, s->K);
7015 assert(ssh->kex->hash->hlen <= sizeof(s->exchange_hash));
7016 ssh->kex->hash->final(ssh->exhash, s->exchange_hash);
7018 ssh->kex_ctx = NULL;
7021 debug(("Exchange hash is:\n"));
7022 dmemdump(s->exchange_hash, ssh->kex->hash->hlen);
7026 !ssh->hostkey->verifysig(s->hkey, s->sigdata, s->siglen,
7027 (char *)s->exchange_hash,
7028 ssh->kex->hash->hlen)) {
7029 bombout(("Server's host key did not match the signature supplied"));
7033 s->keystr = ssh->hostkey->fmtkey(s->hkey);
7034 if (!s->got_session_id) {
7036 * Authenticate remote host: verify host key. (We've already
7037 * checked the signature of the exchange hash.)
7039 s->fingerprint = ssh->hostkey->fingerprint(s->hkey);
7040 logevent("Host key fingerprint is:");
7041 logevent(s->fingerprint);
7042 /* First check against manually configured host keys. */
7043 s->dlgret = verify_ssh_manual_host_key(ssh, s->fingerprint,
7044 ssh->hostkey, s->hkey);
7045 if (s->dlgret == 0) { /* did not match */
7046 bombout(("Host key did not appear in manually configured list"));
7048 } else if (s->dlgret < 0) { /* none configured; use standard handling */
7049 ssh_set_frozen(ssh, 1);
7050 s->dlgret = verify_ssh_host_key(ssh->frontend,
7051 ssh->savedhost, ssh->savedport,
7052 ssh->hostkey->keytype, s->keystr,
7054 ssh_dialog_callback, ssh);
7055 if (s->dlgret < 0) {
7059 bombout(("Unexpected data from server while waiting"
7060 " for user host key response"));
7063 } while (pktin || inlen > 0);
7064 s->dlgret = ssh->user_response;
7066 ssh_set_frozen(ssh, 0);
7067 if (s->dlgret == 0) {
7068 ssh_disconnect(ssh, "Aborted at host key verification", NULL,
7073 sfree(s->fingerprint);
7075 * Save this host key, to check against the one presented in
7076 * subsequent rekeys.
7078 ssh->hostkey_str = s->keystr;
7081 * In a rekey, we never present an interactive host key
7082 * verification request to the user. Instead, we simply
7083 * enforce that the key we're seeing this time is identical to
7084 * the one we saw before.
7086 if (strcmp(ssh->hostkey_str, s->keystr)) {
7087 bombout(("Host key was different in repeat key exchange"));
7092 ssh->hostkey->freekey(s->hkey);
7095 * The exchange hash from the very first key exchange is also
7096 * the session id, used in session key construction and
7099 if (!s->got_session_id) {
7100 assert(sizeof(s->exchange_hash) <= sizeof(ssh->v2_session_id));
7101 memcpy(ssh->v2_session_id, s->exchange_hash,
7102 sizeof(s->exchange_hash));
7103 ssh->v2_session_id_len = ssh->kex->hash->hlen;
7104 assert(ssh->v2_session_id_len <= sizeof(ssh->v2_session_id));
7105 s->got_session_id = TRUE;
7109 * Send SSH2_MSG_NEWKEYS.
7111 s->pktout = ssh2_pkt_init(SSH2_MSG_NEWKEYS);
7112 ssh2_pkt_send_noqueue(ssh, s->pktout);
7113 ssh->outgoing_data_size = 0; /* start counting from here */
7116 * We've sent client NEWKEYS, so create and initialise
7117 * client-to-server session keys.
7119 if (ssh->cs_cipher_ctx)
7120 ssh->cscipher->free_context(ssh->cs_cipher_ctx);
7121 ssh->cscipher = s->cscipher_tobe;
7122 ssh->cs_cipher_ctx = ssh->cscipher->make_context();
7124 if (ssh->cs_mac_ctx)
7125 ssh->csmac->free_context(ssh->cs_mac_ctx);
7126 ssh->csmac = s->csmac_tobe;
7127 ssh->csmac_etm = s->csmac_etm_tobe;
7128 ssh->cs_mac_ctx = ssh->csmac->make_context();
7130 if (ssh->cs_comp_ctx)
7131 ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
7132 ssh->cscomp = s->cscomp_tobe;
7133 ssh->cs_comp_ctx = ssh->cscomp->compress_init();
7136 * Set IVs on client-to-server keys. Here we use the exchange
7137 * hash from the _first_ key exchange.
7140 unsigned char keyspace[SSH2_KEX_MAX_HASH_LEN * SSH2_MKKEY_ITERS];
7141 assert(sizeof(keyspace) >= ssh->kex->hash->hlen * SSH2_MKKEY_ITERS);
7142 ssh2_mkkey(ssh,s->K,s->exchange_hash,'C',keyspace);
7143 assert((ssh->cscipher->keylen+7) / 8 <=
7144 ssh->kex->hash->hlen * SSH2_MKKEY_ITERS);
7145 ssh->cscipher->setkey(ssh->cs_cipher_ctx, keyspace);
7146 ssh2_mkkey(ssh,s->K,s->exchange_hash,'A',keyspace);
7147 assert(ssh->cscipher->blksize <=
7148 ssh->kex->hash->hlen * SSH2_MKKEY_ITERS);
7149 ssh->cscipher->setiv(ssh->cs_cipher_ctx, keyspace);
7150 ssh2_mkkey(ssh,s->K,s->exchange_hash,'E',keyspace);
7151 assert(ssh->csmac->len <=
7152 ssh->kex->hash->hlen * SSH2_MKKEY_ITERS);
7153 ssh->csmac->setkey(ssh->cs_mac_ctx, keyspace);
7154 smemclr(keyspace, sizeof(keyspace));
7157 logeventf(ssh, "Initialised %.200s client->server encryption",
7158 ssh->cscipher->text_name);
7159 logeventf(ssh, "Initialised %.200s client->server MAC algorithm%s",
7160 ssh->csmac->text_name,
7161 ssh->csmac_etm ? " (in ETM mode)" : "");
7162 if (ssh->cscomp->text_name)
7163 logeventf(ssh, "Initialised %s compression",
7164 ssh->cscomp->text_name);
7167 * Now our end of the key exchange is complete, we can send all
7168 * our queued higher-layer packets.
7170 ssh->queueing = FALSE;
7171 ssh2_pkt_queuesend(ssh);
7174 * Expect SSH2_MSG_NEWKEYS from server.
7176 crWaitUntilV(pktin);
7177 if (pktin->type != SSH2_MSG_NEWKEYS) {
7178 bombout(("expected new-keys packet from server"));
7181 ssh->incoming_data_size = 0; /* start counting from here */
7184 * We've seen server NEWKEYS, so create and initialise
7185 * server-to-client session keys.
7187 if (ssh->sc_cipher_ctx)
7188 ssh->sccipher->free_context(ssh->sc_cipher_ctx);
7189 ssh->sccipher = s->sccipher_tobe;
7190 ssh->sc_cipher_ctx = ssh->sccipher->make_context();
7192 if (ssh->sc_mac_ctx)
7193 ssh->scmac->free_context(ssh->sc_mac_ctx);
7194 ssh->scmac = s->scmac_tobe;
7195 ssh->scmac_etm = s->scmac_etm_tobe;
7196 ssh->sc_mac_ctx = ssh->scmac->make_context();
7198 if (ssh->sc_comp_ctx)
7199 ssh->sccomp->decompress_cleanup(ssh->sc_comp_ctx);
7200 ssh->sccomp = s->sccomp_tobe;
7201 ssh->sc_comp_ctx = ssh->sccomp->decompress_init();
7204 * Set IVs on server-to-client keys. Here we use the exchange
7205 * hash from the _first_ key exchange.
7208 unsigned char keyspace[SSH2_KEX_MAX_HASH_LEN * SSH2_MKKEY_ITERS];
7209 assert(sizeof(keyspace) >= ssh->kex->hash->hlen * SSH2_MKKEY_ITERS);
7210 ssh2_mkkey(ssh,s->K,s->exchange_hash,'D',keyspace);
7211 assert((ssh->sccipher->keylen+7) / 8 <=
7212 ssh->kex->hash->hlen * SSH2_MKKEY_ITERS);
7213 ssh->sccipher->setkey(ssh->sc_cipher_ctx, keyspace);
7214 ssh2_mkkey(ssh,s->K,s->exchange_hash,'B',keyspace);
7215 assert(ssh->sccipher->blksize <=
7216 ssh->kex->hash->hlen * SSH2_MKKEY_ITERS);
7217 ssh->sccipher->setiv(ssh->sc_cipher_ctx, keyspace);
7218 ssh2_mkkey(ssh,s->K,s->exchange_hash,'F',keyspace);
7219 assert(ssh->scmac->len <=
7220 ssh->kex->hash->hlen * SSH2_MKKEY_ITERS);
7221 ssh->scmac->setkey(ssh->sc_mac_ctx, keyspace);
7222 smemclr(keyspace, sizeof(keyspace));
7224 logeventf(ssh, "Initialised %.200s server->client encryption",
7225 ssh->sccipher->text_name);
7226 logeventf(ssh, "Initialised %.200s server->client MAC algorithm%s",
7227 ssh->scmac->text_name,
7228 ssh->scmac_etm ? " (in ETM mode)" : "");
7229 if (ssh->sccomp->text_name)
7230 logeventf(ssh, "Initialised %s decompression",
7231 ssh->sccomp->text_name);
7234 * Free shared secret.
7239 * Key exchange is over. Loop straight back round if we have a
7240 * deferred rekey reason.
7242 if (ssh->deferred_rekey_reason) {
7243 logevent(ssh->deferred_rekey_reason);
7245 ssh->deferred_rekey_reason = NULL;
7246 goto begin_key_exchange;
7250 * Otherwise, schedule a timer for our next rekey.
7252 ssh->kex_in_progress = FALSE;
7253 ssh->last_rekey = GETTICKCOUNT();
7254 if (conf_get_int(ssh->conf, CONF_ssh_rekey_time) != 0)
7255 ssh->next_rekey = schedule_timer(conf_get_int(ssh->conf, CONF_ssh_rekey_time)*60*TICKSPERSEC,
7259 * Now we're encrypting. Begin returning 1 to the protocol main
7260 * function so that other things can run on top of the
7261 * transport. If we ever see a KEXINIT, we must go back to the
7264 * We _also_ go back to the start if we see pktin==NULL and
7265 * inlen negative, because this is a special signal meaning
7266 * `initiate client-driven rekey', and `in' contains a message
7267 * giving the reason for the rekey.
7269 * inlen==-1 means always initiate a rekey;
7270 * inlen==-2 means that userauth has completed successfully and
7271 * we should consider rekeying (for delayed compression).
7273 while (!((pktin && pktin->type == SSH2_MSG_KEXINIT) ||
7274 (!pktin && inlen < 0))) {
7276 if (!ssh->protocol_initial_phase_done) {
7277 ssh->protocol_initial_phase_done = TRUE;
7279 * Allow authconn to initialise itself.
7281 do_ssh2_authconn(ssh, NULL, 0, NULL);
7286 logevent("Server initiated key re-exchange");
7290 * authconn has seen a USERAUTH_SUCCEEDED. Time to enable
7291 * delayed compression, if it's available.
7293 * draft-miller-secsh-compression-delayed-00 says that you
7294 * negotiate delayed compression in the first key exchange, and
7295 * both sides start compressing when the server has sent
7296 * USERAUTH_SUCCESS. This has a race condition -- the server
7297 * can't know when the client has seen it, and thus which incoming
7298 * packets it should treat as compressed.
7300 * Instead, we do the initial key exchange without offering the
7301 * delayed methods, but note if the server offers them; when we
7302 * get here, if a delayed method was available that was higher
7303 * on our list than what we got, we initiate a rekey in which we
7304 * _do_ list the delayed methods (and hopefully get it as a
7305 * result). Subsequent rekeys will do the same.
7307 assert(!s->userauth_succeeded); /* should only happen once */
7308 s->userauth_succeeded = TRUE;
7309 if (!s->pending_compression)
7310 /* Can't see any point rekeying. */
7311 goto wait_for_rekey; /* this is utterly horrid */
7312 /* else fall through to rekey... */
7313 s->pending_compression = FALSE;
7316 * Now we've decided to rekey.
7318 * Special case: if the server bug is set that doesn't
7319 * allow rekeying, we give a different log message and
7320 * continue waiting. (If such a server _initiates_ a rekey,
7321 * we process it anyway!)
7323 if ((ssh->remote_bugs & BUG_SSH2_REKEY)) {
7324 logeventf(ssh, "Server bug prevents key re-exchange (%s)",
7326 /* Reset the counters, so that at least this message doesn't
7327 * hit the event log _too_ often. */
7328 ssh->outgoing_data_size = 0;
7329 ssh->incoming_data_size = 0;
7330 if (conf_get_int(ssh->conf, CONF_ssh_rekey_time) != 0) {
7332 schedule_timer(conf_get_int(ssh->conf, CONF_ssh_rekey_time)*60*TICKSPERSEC,
7335 goto wait_for_rekey; /* this is still utterly horrid */
7337 logeventf(ssh, "Initiating key re-exchange (%s)", (char *)in);
7340 goto begin_key_exchange;
7346 * Add data to an SSH-2 channel output buffer.
7348 static void ssh2_add_channel_data(struct ssh_channel *c, char *buf,
7351 bufchain_add(&c->v.v2.outbuffer, buf, len);
7355 * Attempt to send data on an SSH-2 channel.
7357 static int ssh2_try_send(struct ssh_channel *c)
7360 struct Packet *pktout;
7363 while (c->v.v2.remwindow > 0 && bufchain_size(&c->v.v2.outbuffer) > 0) {
7366 bufchain_prefix(&c->v.v2.outbuffer, &data, &len);
7367 if ((unsigned)len > c->v.v2.remwindow)
7368 len = c->v.v2.remwindow;
7369 if ((unsigned)len > c->v.v2.remmaxpkt)
7370 len = c->v.v2.remmaxpkt;
7371 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_DATA);
7372 ssh2_pkt_adduint32(pktout, c->remoteid);
7373 ssh2_pkt_addstring_start(pktout);
7374 ssh2_pkt_addstring_data(pktout, data, len);
7375 ssh2_pkt_send(ssh, pktout);
7376 bufchain_consume(&c->v.v2.outbuffer, len);
7377 c->v.v2.remwindow -= len;
7381 * After having sent as much data as we can, return the amount
7384 ret = bufchain_size(&c->v.v2.outbuffer);
7387 * And if there's no data pending but we need to send an EOF, send
7390 if (!ret && c->pending_eof)
7391 ssh_channel_try_eof(c);
7396 static void ssh2_try_send_and_unthrottle(Ssh ssh, struct ssh_channel *c)
7399 if (c->closes & CLOSES_SENT_EOF)
7400 return; /* don't send on channels we've EOFed */
7401 bufsize = ssh2_try_send(c);
7404 case CHAN_MAINSESSION:
7405 /* stdin need not receive an unthrottle
7406 * notification since it will be polled */
7409 x11_unthrottle(c->u.x11.xconn);
7412 /* agent sockets are request/response and need no
7413 * buffer management */
7416 pfd_unthrottle(c->u.pfd.pf);
7422 static int ssh_is_simple(Ssh ssh)
7425 * We use the 'simple' variant of the SSH protocol if we're asked
7426 * to, except not if we're also doing connection-sharing (either
7427 * tunnelling our packets over an upstream or expecting to be
7428 * tunnelled over ourselves), since then the assumption that we
7429 * have only one channel to worry about is not true after all.
7431 return (conf_get_int(ssh->conf, CONF_ssh_simple) &&
7432 !ssh->bare_connection && !ssh->connshare);
7436 * Set up most of a new ssh_channel for SSH-2.
7438 static void ssh2_channel_init(struct ssh_channel *c)
7441 c->localid = alloc_channel_id(ssh);
7443 c->pending_eof = FALSE;
7444 c->throttling_conn = FALSE;
7445 c->v.v2.locwindow = c->v.v2.locmaxwin = c->v.v2.remlocwin =
7446 ssh_is_simple(ssh) ? OUR_V2_BIGWIN : OUR_V2_WINSIZE;
7447 c->v.v2.chanreq_head = NULL;
7448 c->v.v2.throttle_state = UNTHROTTLED;
7449 bufchain_init(&c->v.v2.outbuffer);
7453 * Construct the common parts of a CHANNEL_OPEN.
7455 static struct Packet *ssh2_chanopen_init(struct ssh_channel *c, char *type)
7457 struct Packet *pktout;
7459 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN);
7460 ssh2_pkt_addstring(pktout, type);
7461 ssh2_pkt_adduint32(pktout, c->localid);
7462 ssh2_pkt_adduint32(pktout, c->v.v2.locwindow);/* our window size */
7463 ssh2_pkt_adduint32(pktout, OUR_V2_MAXPKT); /* our max pkt size */
7468 * CHANNEL_FAILURE doesn't come with any indication of what message
7469 * caused it, so we have to keep track of the outstanding
7470 * CHANNEL_REQUESTs ourselves.
7472 static void ssh2_queue_chanreq_handler(struct ssh_channel *c,
7473 cchandler_fn_t handler, void *ctx)
7475 struct outstanding_channel_request *ocr =
7476 snew(struct outstanding_channel_request);
7478 assert(!(c->closes & (CLOSES_SENT_CLOSE | CLOSES_RCVD_CLOSE)));
7479 ocr->handler = handler;
7482 if (!c->v.v2.chanreq_head)
7483 c->v.v2.chanreq_head = ocr;
7485 c->v.v2.chanreq_tail->next = ocr;
7486 c->v.v2.chanreq_tail = ocr;
7490 * Construct the common parts of a CHANNEL_REQUEST. If handler is not
7491 * NULL then a reply will be requested and the handler will be called
7492 * when it arrives. The returned packet is ready to have any
7493 * request-specific data added and be sent. Note that if a handler is
7494 * provided, it's essential that the request actually be sent.
7496 * The handler will usually be passed the response packet in pktin. If
7497 * pktin is NULL, this means that no reply will ever be forthcoming
7498 * (e.g. because the entire connection is being destroyed, or because
7499 * the server initiated channel closure before we saw the response)
7500 * and the handler should free any storage it's holding.
7502 static struct Packet *ssh2_chanreq_init(struct ssh_channel *c, char *type,
7503 cchandler_fn_t handler, void *ctx)
7505 struct Packet *pktout;
7507 assert(!(c->closes & (CLOSES_SENT_CLOSE | CLOSES_RCVD_CLOSE)));
7508 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
7509 ssh2_pkt_adduint32(pktout, c->remoteid);
7510 ssh2_pkt_addstring(pktout, type);
7511 ssh2_pkt_addbool(pktout, handler != NULL);
7512 if (handler != NULL)
7513 ssh2_queue_chanreq_handler(c, handler, ctx);
7518 * Potentially enlarge the window on an SSH-2 channel.
7520 static void ssh2_handle_winadj_response(struct ssh_channel *, struct Packet *,
7522 static void ssh2_set_window(struct ssh_channel *c, int newwin)
7527 * Never send WINDOW_ADJUST for a channel that the remote side has
7528 * already sent EOF on; there's no point, since it won't be
7529 * sending any more data anyway. Ditto if _we've_ already sent
7532 if (c->closes & (CLOSES_RCVD_EOF | CLOSES_SENT_CLOSE))
7536 * Also, never widen the window for an X11 channel when we're
7537 * still waiting to see its initial auth and may yet hand it off
7540 if (c->type == CHAN_X11 && c->u.x11.initial)
7544 * If the remote end has a habit of ignoring maxpkt, limit the
7545 * window so that it has no choice (assuming it doesn't ignore the
7548 if ((ssh->remote_bugs & BUG_SSH2_MAXPKT) && newwin > OUR_V2_MAXPKT)
7549 newwin = OUR_V2_MAXPKT;
7552 * Only send a WINDOW_ADJUST if there's significantly more window
7553 * available than the other end thinks there is. This saves us
7554 * sending a WINDOW_ADJUST for every character in a shell session.
7556 * "Significant" is arbitrarily defined as half the window size.
7558 if (newwin / 2 >= c->v.v2.locwindow) {
7559 struct Packet *pktout;
7563 * In order to keep track of how much window the client
7564 * actually has available, we'd like it to acknowledge each
7565 * WINDOW_ADJUST. We can't do that directly, so we accompany
7566 * it with a CHANNEL_REQUEST that has to be acknowledged.
7568 * This is only necessary if we're opening the window wide.
7569 * If we're not, then throughput is being constrained by
7570 * something other than the maximum window size anyway.
7572 if (newwin == c->v.v2.locmaxwin &&
7573 !(ssh->remote_bugs & BUG_CHOKES_ON_WINADJ)) {
7574 up = snew(unsigned);
7575 *up = newwin - c->v.v2.locwindow;
7576 pktout = ssh2_chanreq_init(c, "winadj@putty.projects.tartarus.org",
7577 ssh2_handle_winadj_response, up);
7578 ssh2_pkt_send(ssh, pktout);
7580 if (c->v.v2.throttle_state != UNTHROTTLED)
7581 c->v.v2.throttle_state = UNTHROTTLING;
7583 /* Pretend the WINDOW_ADJUST was acked immediately. */
7584 c->v.v2.remlocwin = newwin;
7585 c->v.v2.throttle_state = THROTTLED;
7587 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
7588 ssh2_pkt_adduint32(pktout, c->remoteid);
7589 ssh2_pkt_adduint32(pktout, newwin - c->v.v2.locwindow);
7590 ssh2_pkt_send(ssh, pktout);
7591 c->v.v2.locwindow = newwin;
7596 * Find the channel associated with a message. If there's no channel,
7597 * or it's not properly open, make a noise about it and return NULL.
7599 static struct ssh_channel *ssh2_channel_msg(Ssh ssh, struct Packet *pktin)
7601 unsigned localid = ssh_pkt_getuint32(pktin);
7602 struct ssh_channel *c;
7604 c = find234(ssh->channels, &localid, ssh_channelfind);
7606 (c->type != CHAN_SHARING && c->halfopen &&
7607 pktin->type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION &&
7608 pktin->type != SSH2_MSG_CHANNEL_OPEN_FAILURE)) {
7609 char *buf = dupprintf("Received %s for %s channel %u",
7610 ssh2_pkt_type(ssh->pkt_kctx, ssh->pkt_actx,
7612 c ? "half-open" : "nonexistent", localid);
7613 ssh_disconnect(ssh, NULL, buf, SSH2_DISCONNECT_PROTOCOL_ERROR, FALSE);
7620 static void ssh2_handle_winadj_response(struct ssh_channel *c,
7621 struct Packet *pktin, void *ctx)
7623 unsigned *sizep = ctx;
7626 * Winadj responses should always be failures. However, at least
7627 * one server ("boks_sshd") is known to return SUCCESS for channel
7628 * requests it's never heard of, such as "winadj@putty". Raised
7629 * with foxt.com as bug 090916-090424, but for the sake of a quiet
7630 * life, we don't worry about what kind of response we got.
7633 c->v.v2.remlocwin += *sizep;
7636 * winadj messages are only sent when the window is fully open, so
7637 * if we get an ack of one, we know any pending unthrottle is
7640 if (c->v.v2.throttle_state == UNTHROTTLING)
7641 c->v.v2.throttle_state = UNTHROTTLED;
7644 static void ssh2_msg_channel_response(Ssh ssh, struct Packet *pktin)
7646 struct ssh_channel *c = ssh2_channel_msg(ssh, pktin);
7647 struct outstanding_channel_request *ocr;
7650 if (c->type == CHAN_SHARING) {
7651 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
7652 pktin->body, pktin->length);
7655 ocr = c->v.v2.chanreq_head;
7657 ssh2_msg_unexpected(ssh, pktin);
7660 ocr->handler(c, pktin, ocr->ctx);
7661 c->v.v2.chanreq_head = ocr->next;
7664 * We may now initiate channel-closing procedures, if that
7665 * CHANNEL_REQUEST was the last thing outstanding before we send
7668 ssh2_channel_check_close(c);
7671 static void ssh2_msg_channel_window_adjust(Ssh ssh, struct Packet *pktin)
7673 struct ssh_channel *c;
7674 c = ssh2_channel_msg(ssh, pktin);
7677 if (c->type == CHAN_SHARING) {
7678 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
7679 pktin->body, pktin->length);
7682 if (!(c->closes & CLOSES_SENT_EOF)) {
7683 c->v.v2.remwindow += ssh_pkt_getuint32(pktin);
7684 ssh2_try_send_and_unthrottle(ssh, c);
7688 static void ssh2_msg_channel_data(Ssh ssh, struct Packet *pktin)
7692 struct ssh_channel *c;
7693 c = ssh2_channel_msg(ssh, pktin);
7696 if (c->type == CHAN_SHARING) {
7697 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
7698 pktin->body, pktin->length);
7701 if (pktin->type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
7702 ssh_pkt_getuint32(pktin) != SSH2_EXTENDED_DATA_STDERR)
7703 return; /* extended but not stderr */
7704 ssh_pkt_getstring(pktin, &data, &length);
7707 c->v.v2.locwindow -= length;
7708 c->v.v2.remlocwin -= length;
7710 case CHAN_MAINSESSION:
7712 from_backend(ssh->frontend, pktin->type ==
7713 SSH2_MSG_CHANNEL_EXTENDED_DATA,
7717 bufsize = x11_send(c->u.x11.xconn, data, length);
7720 bufsize = pfd_send(c->u.pfd.pf, data, length);
7723 while (length > 0) {
7724 if (c->u.a.lensofar < 4) {
7725 unsigned int l = min(4 - c->u.a.lensofar,
7727 memcpy(c->u.a.msglen + c->u.a.lensofar,
7731 c->u.a.lensofar += l;
7733 if (c->u.a.lensofar == 4) {
7735 4 + GET_32BIT(c->u.a.msglen);
7736 c->u.a.message = snewn(c->u.a.totallen,
7738 memcpy(c->u.a.message, c->u.a.msglen, 4);
7740 if (c->u.a.lensofar >= 4 && length > 0) {
7742 min(c->u.a.totallen - c->u.a.lensofar,
7744 memcpy(c->u.a.message + c->u.a.lensofar,
7748 c->u.a.lensofar += l;
7750 if (c->u.a.lensofar == c->u.a.totallen) {
7753 c->u.a.outstanding_requests++;
7754 if (agent_query(c->u.a.message,
7757 ssh_agentf_callback, c))
7758 ssh_agentf_callback(c, reply, replylen);
7759 sfree(c->u.a.message);
7760 c->u.a.message = NULL;
7761 c->u.a.lensofar = 0;
7768 * If it looks like the remote end hit the end of its window,
7769 * and we didn't want it to do that, think about using a
7772 if (c->v.v2.remlocwin <= 0 && c->v.v2.throttle_state == UNTHROTTLED &&
7773 c->v.v2.locmaxwin < 0x40000000)
7774 c->v.v2.locmaxwin += OUR_V2_WINSIZE;
7776 * If we are not buffering too much data,
7777 * enlarge the window again at the remote side.
7778 * If we are buffering too much, we may still
7779 * need to adjust the window if the server's
7782 ssh2_set_window(c, bufsize < c->v.v2.locmaxwin ?
7783 c->v.v2.locmaxwin - bufsize : 0);
7785 * If we're either buffering way too much data, or if we're
7786 * buffering anything at all and we're in "simple" mode,
7787 * throttle the whole channel.
7789 if ((bufsize > c->v.v2.locmaxwin || (ssh_is_simple(ssh) && bufsize>0))
7790 && !c->throttling_conn) {
7791 c->throttling_conn = 1;
7792 ssh_throttle_conn(ssh, +1);
7797 static void ssh_check_termination(Ssh ssh)
7799 if (ssh->version == 2 &&
7800 !conf_get_int(ssh->conf, CONF_ssh_no_shell) &&
7801 count234(ssh->channels) == 0 &&
7802 !(ssh->connshare && share_ndownstreams(ssh->connshare) > 0)) {
7804 * We used to send SSH_MSG_DISCONNECT here, because I'd
7805 * believed that _every_ conforming SSH-2 connection had to
7806 * end with a disconnect being sent by at least one side;
7807 * apparently I was wrong and it's perfectly OK to
7808 * unceremoniously slam the connection shut when you're done,
7809 * and indeed OpenSSH feels this is more polite than sending a
7810 * DISCONNECT. So now we don't.
7812 ssh_disconnect(ssh, "All channels closed", NULL, 0, TRUE);
7816 void ssh_sharing_downstream_connected(Ssh ssh, unsigned id)
7818 logeventf(ssh, "Connection sharing downstream #%u connected", id);
7821 void ssh_sharing_downstream_disconnected(Ssh ssh, unsigned id)
7823 logeventf(ssh, "Connection sharing downstream #%u disconnected", id);
7824 ssh_check_termination(ssh);
7827 void ssh_sharing_logf(Ssh ssh, unsigned id, const char *logfmt, ...)
7832 va_start(ap, logfmt);
7833 buf = dupvprintf(logfmt, ap);
7836 logeventf(ssh, "Connection sharing downstream #%u: %s", id, buf);
7838 logeventf(ssh, "Connection sharing: %s", buf);
7842 static void ssh_channel_destroy(struct ssh_channel *c)
7847 case CHAN_MAINSESSION:
7848 ssh->mainchan = NULL;
7849 update_specials_menu(ssh->frontend);
7852 if (c->u.x11.xconn != NULL)
7853 x11_close(c->u.x11.xconn);
7854 logevent("Forwarded X11 connection terminated");
7857 sfree(c->u.a.message);
7860 if (c->u.pfd.pf != NULL)
7861 pfd_close(c->u.pfd.pf);
7862 logevent("Forwarded port closed");
7866 del234(ssh->channels, c);
7867 if (ssh->version == 2) {
7868 bufchain_clear(&c->v.v2.outbuffer);
7869 assert(c->v.v2.chanreq_head == NULL);
7874 * If that was the last channel left open, we might need to
7877 ssh_check_termination(ssh);
7880 static void ssh2_channel_check_close(struct ssh_channel *c)
7883 struct Packet *pktout;
7887 * If we've sent out our own CHANNEL_OPEN but not yet seen
7888 * either OPEN_CONFIRMATION or OPEN_FAILURE in response, then
7889 * it's too early to be sending close messages of any kind.
7894 if ((!((CLOSES_SENT_EOF | CLOSES_RCVD_EOF) & ~c->closes) ||
7895 c->type == CHAN_ZOMBIE) &&
7896 !c->v.v2.chanreq_head &&
7897 !(c->closes & CLOSES_SENT_CLOSE)) {
7899 * We have both sent and received EOF (or the channel is a
7900 * zombie), and we have no outstanding channel requests, which
7901 * means the channel is in final wind-up. But we haven't sent
7902 * CLOSE, so let's do so now.
7904 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE);
7905 ssh2_pkt_adduint32(pktout, c->remoteid);
7906 ssh2_pkt_send(ssh, pktout);
7907 c->closes |= CLOSES_SENT_EOF | CLOSES_SENT_CLOSE;
7910 if (!((CLOSES_SENT_CLOSE | CLOSES_RCVD_CLOSE) & ~c->closes)) {
7911 assert(c->v.v2.chanreq_head == NULL);
7913 * We have both sent and received CLOSE, which means we're
7914 * completely done with the channel.
7916 ssh_channel_destroy(c);
7920 static void ssh2_channel_got_eof(struct ssh_channel *c)
7922 if (c->closes & CLOSES_RCVD_EOF)
7923 return; /* already seen EOF */
7924 c->closes |= CLOSES_RCVD_EOF;
7926 if (c->type == CHAN_X11) {
7927 x11_send_eof(c->u.x11.xconn);
7928 } else if (c->type == CHAN_AGENT) {
7929 if (c->u.a.outstanding_requests == 0) {
7930 /* Manufacture an outgoing EOF in response to the incoming one. */
7931 sshfwd_write_eof(c);
7933 } else if (c->type == CHAN_SOCKDATA) {
7934 pfd_send_eof(c->u.pfd.pf);
7935 } else if (c->type == CHAN_MAINSESSION) {
7938 if (!ssh->sent_console_eof &&
7939 (from_backend_eof(ssh->frontend) || ssh->got_pty)) {
7941 * Either from_backend_eof told us that the front end
7942 * wants us to close the outgoing side of the connection
7943 * as soon as we see EOF from the far end, or else we've
7944 * unilaterally decided to do that because we've allocated
7945 * a remote pty and hence EOF isn't a particularly
7946 * meaningful concept.
7948 sshfwd_write_eof(c);
7950 ssh->sent_console_eof = TRUE;
7953 ssh2_channel_check_close(c);
7956 static void ssh2_msg_channel_eof(Ssh ssh, struct Packet *pktin)
7958 struct ssh_channel *c;
7960 c = ssh2_channel_msg(ssh, pktin);
7963 if (c->type == CHAN_SHARING) {
7964 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
7965 pktin->body, pktin->length);
7968 ssh2_channel_got_eof(c);
7971 static void ssh2_msg_channel_close(Ssh ssh, struct Packet *pktin)
7973 struct ssh_channel *c;
7975 c = ssh2_channel_msg(ssh, pktin);
7978 if (c->type == CHAN_SHARING) {
7979 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
7980 pktin->body, pktin->length);
7985 * When we receive CLOSE on a channel, we assume it comes with an
7986 * implied EOF if we haven't seen EOF yet.
7988 ssh2_channel_got_eof(c);
7990 if (!(ssh->remote_bugs & BUG_SENDS_LATE_REQUEST_REPLY)) {
7992 * It also means we stop expecting to see replies to any
7993 * outstanding channel requests, so clean those up too.
7994 * (ssh_chanreq_init will enforce by assertion that we don't
7995 * subsequently put anything back on this list.)
7997 while (c->v.v2.chanreq_head) {
7998 struct outstanding_channel_request *ocr = c->v.v2.chanreq_head;
7999 ocr->handler(c, NULL, ocr->ctx);
8000 c->v.v2.chanreq_head = ocr->next;
8006 * And we also send an outgoing EOF, if we haven't already, on the
8007 * assumption that CLOSE is a pretty forceful announcement that
8008 * the remote side is doing away with the entire channel. (If it
8009 * had wanted to send us EOF and continue receiving data from us,
8010 * it would have just sent CHANNEL_EOF.)
8012 if (!(c->closes & CLOSES_SENT_EOF)) {
8014 * Make sure we don't read any more from whatever our local
8015 * data source is for this channel.
8018 case CHAN_MAINSESSION:
8019 ssh->send_ok = 0; /* stop trying to read from stdin */
8022 x11_override_throttle(c->u.x11.xconn, 1);
8025 pfd_override_throttle(c->u.pfd.pf, 1);
8030 * Abandon any buffered data we still wanted to send to this
8031 * channel. Receiving a CHANNEL_CLOSE is an indication that
8032 * the server really wants to get on and _destroy_ this
8033 * channel, and it isn't going to send us any further
8034 * WINDOW_ADJUSTs to permit us to send pending stuff.
8036 bufchain_clear(&c->v.v2.outbuffer);
8039 * Send outgoing EOF.
8041 sshfwd_write_eof(c);
8045 * Now process the actual close.
8047 if (!(c->closes & CLOSES_RCVD_CLOSE)) {
8048 c->closes |= CLOSES_RCVD_CLOSE;
8049 ssh2_channel_check_close(c);
8053 static void ssh2_msg_channel_open_confirmation(Ssh ssh, struct Packet *pktin)
8055 struct ssh_channel *c;
8057 c = ssh2_channel_msg(ssh, pktin);
8060 if (c->type == CHAN_SHARING) {
8061 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
8062 pktin->body, pktin->length);
8065 assert(c->halfopen); /* ssh2_channel_msg will have enforced this */
8066 c->remoteid = ssh_pkt_getuint32(pktin);
8067 c->halfopen = FALSE;
8068 c->v.v2.remwindow = ssh_pkt_getuint32(pktin);
8069 c->v.v2.remmaxpkt = ssh_pkt_getuint32(pktin);
8071 if (c->type == CHAN_SOCKDATA_DORMANT) {
8072 c->type = CHAN_SOCKDATA;
8074 pfd_confirm(c->u.pfd.pf);
8075 } else if (c->type == CHAN_ZOMBIE) {
8077 * This case can occur if a local socket error occurred
8078 * between us sending out CHANNEL_OPEN and receiving
8079 * OPEN_CONFIRMATION. In this case, all we can do is
8080 * immediately initiate close proceedings now that we know the
8081 * server's id to put in the close message.
8083 ssh2_channel_check_close(c);
8086 * We never expect to receive OPEN_CONFIRMATION for any
8087 * *other* channel type (since only local-to-remote port
8088 * forwardings cause us to send CHANNEL_OPEN after the main
8089 * channel is live - all other auxiliary channel types are
8090 * initiated from the server end). It's safe to enforce this
8091 * by assertion rather than by ssh_disconnect, because the
8092 * real point is that we never constructed a half-open channel
8093 * structure in the first place with any type other than the
8096 assert(!"Funny channel type in ssh2_msg_channel_open_confirmation");
8100 ssh_channel_try_eof(c); /* in case we had a pending EOF */
8103 static void ssh2_msg_channel_open_failure(Ssh ssh, struct Packet *pktin)
8105 static const char *const reasons[] = {
8106 "<unknown reason code>",
8107 "Administratively prohibited",
8109 "Unknown channel type",
8110 "Resource shortage",
8112 unsigned reason_code;
8113 char *reason_string;
8115 struct ssh_channel *c;
8117 c = ssh2_channel_msg(ssh, pktin);
8120 if (c->type == CHAN_SHARING) {
8121 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
8122 pktin->body, pktin->length);
8125 assert(c->halfopen); /* ssh2_channel_msg will have enforced this */
8127 if (c->type == CHAN_SOCKDATA_DORMANT) {
8128 reason_code = ssh_pkt_getuint32(pktin);
8129 if (reason_code >= lenof(reasons))
8130 reason_code = 0; /* ensure reasons[reason_code] in range */
8131 ssh_pkt_getstring(pktin, &reason_string, &reason_length);
8132 logeventf(ssh, "Forwarded connection refused by server: %s [%.*s]",
8133 reasons[reason_code], reason_length, reason_string);
8135 pfd_close(c->u.pfd.pf);
8136 } else if (c->type == CHAN_ZOMBIE) {
8138 * This case can occur if a local socket error occurred
8139 * between us sending out CHANNEL_OPEN and receiving
8140 * OPEN_FAILURE. In this case, we need do nothing except allow
8141 * the code below to throw the half-open channel away.
8145 * We never expect to receive OPEN_FAILURE for any *other*
8146 * channel type (since only local-to-remote port forwardings
8147 * cause us to send CHANNEL_OPEN after the main channel is
8148 * live - all other auxiliary channel types are initiated from
8149 * the server end). It's safe to enforce this by assertion
8150 * rather than by ssh_disconnect, because the real point is
8151 * that we never constructed a half-open channel structure in
8152 * the first place with any type other than the above.
8154 assert(!"Funny channel type in ssh2_msg_channel_open_failure");
8157 del234(ssh->channels, c);
8161 static void ssh2_msg_channel_request(Ssh ssh, struct Packet *pktin)
8164 int typelen, want_reply;
8165 int reply = SSH2_MSG_CHANNEL_FAILURE; /* default */
8166 struct ssh_channel *c;
8167 struct Packet *pktout;
8169 c = ssh2_channel_msg(ssh, pktin);
8172 if (c->type == CHAN_SHARING) {
8173 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
8174 pktin->body, pktin->length);
8177 ssh_pkt_getstring(pktin, &type, &typelen);
8178 want_reply = ssh2_pkt_getbool(pktin);
8180 if (c->closes & CLOSES_SENT_CLOSE) {
8182 * We don't reply to channel requests after we've sent
8183 * CHANNEL_CLOSE for the channel, because our reply might
8184 * cross in the network with the other side's CHANNEL_CLOSE
8185 * and arrive after they have wound the channel up completely.
8191 * Having got the channel number, we now look at
8192 * the request type string to see if it's something
8195 if (c == ssh->mainchan) {
8197 * We recognise "exit-status" and "exit-signal" on
8198 * the primary channel.
8200 if (typelen == 11 &&
8201 !memcmp(type, "exit-status", 11)) {
8203 ssh->exitcode = ssh_pkt_getuint32(pktin);
8204 logeventf(ssh, "Server sent command exit status %d",
8206 reply = SSH2_MSG_CHANNEL_SUCCESS;
8208 } else if (typelen == 11 &&
8209 !memcmp(type, "exit-signal", 11)) {
8211 int is_plausible = TRUE, is_int = FALSE;
8212 char *fmt_sig = "", *fmt_msg = "";
8214 int msglen = 0, core = FALSE;
8215 /* ICK: older versions of OpenSSH (e.g. 3.4p1)
8216 * provide an `int' for the signal, despite its
8217 * having been a `string' in the drafts of RFC 4254 since at
8218 * least 2001. (Fixed in session.c 1.147.) Try to
8219 * infer which we can safely parse it as. */
8221 unsigned char *p = pktin->body +
8223 long len = pktin->length - pktin->savedpos;
8224 unsigned long num = GET_32BIT(p); /* what is it? */
8225 /* If it's 0, it hardly matters; assume string */
8229 int maybe_int = FALSE, maybe_str = FALSE;
8230 #define CHECK_HYPOTHESIS(offset, result) \
8233 int q = toint(offset); \
8234 if (q >= 0 && q+4 <= len) { \
8235 q = toint(q + 4 + GET_32BIT(p+q)); \
8236 if (q >= 0 && q+4 <= len && \
8237 ((q = toint(q + 4 + GET_32BIT(p+q))) != 0) && \
8242 CHECK_HYPOTHESIS(4+1, maybe_int);
8243 CHECK_HYPOTHESIS(4+num+1, maybe_str);
8244 #undef CHECK_HYPOTHESIS
8245 if (maybe_int && !maybe_str)
8247 else if (!maybe_int && maybe_str)
8250 /* Crikey. Either or neither. Panic. */
8251 is_plausible = FALSE;
8254 ssh->exitcode = 128; /* means `unknown signal' */
8257 /* Old non-standard OpenSSH. */
8258 int signum = ssh_pkt_getuint32(pktin);
8259 fmt_sig = dupprintf(" %d", signum);
8260 ssh->exitcode = 128 + signum;
8262 /* As per RFC 4254. */
8265 ssh_pkt_getstring(pktin, &sig, &siglen);
8266 /* Signal name isn't supposed to be blank, but
8267 * let's cope gracefully if it is. */
8269 fmt_sig = dupprintf(" \"%.*s\"",
8274 * Really hideous method of translating the
8275 * signal description back into a locally
8276 * meaningful number.
8281 #define TRANSLATE_SIGNAL(s) \
8282 else if (siglen == lenof(#s)-1 && !memcmp(sig, #s, siglen)) \
8283 ssh->exitcode = 128 + SIG ## s
8285 TRANSLATE_SIGNAL(ABRT);
8288 TRANSLATE_SIGNAL(ALRM);
8291 TRANSLATE_SIGNAL(FPE);
8294 TRANSLATE_SIGNAL(HUP);
8297 TRANSLATE_SIGNAL(ILL);
8300 TRANSLATE_SIGNAL(INT);
8303 TRANSLATE_SIGNAL(KILL);
8306 TRANSLATE_SIGNAL(PIPE);
8309 TRANSLATE_SIGNAL(QUIT);
8312 TRANSLATE_SIGNAL(SEGV);
8315 TRANSLATE_SIGNAL(TERM);
8318 TRANSLATE_SIGNAL(USR1);
8321 TRANSLATE_SIGNAL(USR2);
8323 #undef TRANSLATE_SIGNAL
8325 ssh->exitcode = 128;
8327 core = ssh2_pkt_getbool(pktin);
8328 ssh_pkt_getstring(pktin, &msg, &msglen);
8330 fmt_msg = dupprintf(" (\"%.*s\")", msglen, msg);
8332 /* ignore lang tag */
8333 } /* else don't attempt to parse */
8334 logeventf(ssh, "Server exited on signal%s%s%s",
8335 fmt_sig, core ? " (core dumped)" : "",
8337 if (*fmt_sig) sfree(fmt_sig);
8338 if (*fmt_msg) sfree(fmt_msg);
8339 reply = SSH2_MSG_CHANNEL_SUCCESS;
8344 * This is a channel request we don't know
8345 * about, so we now either ignore the request
8346 * or respond with CHANNEL_FAILURE, depending
8349 reply = SSH2_MSG_CHANNEL_FAILURE;
8352 pktout = ssh2_pkt_init(reply);
8353 ssh2_pkt_adduint32(pktout, c->remoteid);
8354 ssh2_pkt_send(ssh, pktout);
8358 static void ssh2_msg_global_request(Ssh ssh, struct Packet *pktin)
8361 int typelen, want_reply;
8362 struct Packet *pktout;
8364 ssh_pkt_getstring(pktin, &type, &typelen);
8365 want_reply = ssh2_pkt_getbool(pktin);
8368 * We currently don't support any global requests
8369 * at all, so we either ignore the request or
8370 * respond with REQUEST_FAILURE, depending on
8374 pktout = ssh2_pkt_init(SSH2_MSG_REQUEST_FAILURE);
8375 ssh2_pkt_send(ssh, pktout);
8379 struct X11FakeAuth *ssh_sharing_add_x11_display(Ssh ssh, int authtype,
8383 struct X11FakeAuth *auth;
8386 * Make up a new set of fake X11 auth data, and add it to the tree
8387 * of currently valid ones with an indication of the sharing
8388 * context that it's relevant to.
8390 auth = x11_invent_fake_auth(ssh->x11authtree, authtype);
8391 auth->share_cs = share_cs;
8392 auth->share_chan = share_chan;
8397 void ssh_sharing_remove_x11_display(Ssh ssh, struct X11FakeAuth *auth)
8399 del234(ssh->x11authtree, auth);
8400 x11_free_fake_auth(auth);
8403 static void ssh2_msg_channel_open(Ssh ssh, struct Packet *pktin)
8411 struct ssh_channel *c;
8412 unsigned remid, winsize, pktsize;
8413 unsigned our_winsize_override = 0;
8414 struct Packet *pktout;
8416 ssh_pkt_getstring(pktin, &type, &typelen);
8417 c = snew(struct ssh_channel);
8420 remid = ssh_pkt_getuint32(pktin);
8421 winsize = ssh_pkt_getuint32(pktin);
8422 pktsize = ssh_pkt_getuint32(pktin);
8424 if (typelen == 3 && !memcmp(type, "x11", 3)) {
8427 ssh_pkt_getstring(pktin, &peeraddr, &peeraddrlen);
8428 addrstr = snewn(peeraddrlen+1, char);
8429 memcpy(addrstr, peeraddr, peeraddrlen);
8430 addrstr[peeraddrlen] = '\0';
8431 peerport = ssh_pkt_getuint32(pktin);
8433 logeventf(ssh, "Received X11 connect request from %s:%d",
8436 if (!ssh->X11_fwd_enabled && !ssh->connshare)
8437 error = "X11 forwarding is not enabled";
8439 c->u.x11.xconn = x11_init(ssh->x11authtree, c,
8442 c->u.x11.initial = TRUE;
8445 * If we are a connection-sharing upstream, then we should
8446 * initially present a very small window, adequate to take
8447 * the X11 initial authorisation packet but not much more.
8448 * Downstream will then present us a larger window (by
8449 * fiat of the connection-sharing protocol) and we can
8450 * guarantee to send a positive-valued WINDOW_ADJUST.
8453 our_winsize_override = 128;
8455 logevent("Opened X11 forward channel");
8459 } else if (typelen == 15 &&
8460 !memcmp(type, "forwarded-tcpip", 15)) {
8461 struct ssh_rportfwd pf, *realpf;
8464 ssh_pkt_getstring(pktin, &shost, &shostlen);/* skip address */
8465 pf.shost = dupprintf("%.*s", shostlen, shost);
8466 pf.sport = ssh_pkt_getuint32(pktin);
8467 ssh_pkt_getstring(pktin, &peeraddr, &peeraddrlen);
8468 peerport = ssh_pkt_getuint32(pktin);
8469 realpf = find234(ssh->rportfwds, &pf, NULL);
8470 logeventf(ssh, "Received remote port %s:%d open request "
8471 "from %s:%d", pf.shost, pf.sport, peeraddr, peerport);
8474 if (realpf == NULL) {
8475 error = "Remote port is not recognised";
8479 if (realpf->share_ctx) {
8481 * This port forwarding is on behalf of a
8482 * connection-sharing downstream, so abandon our own
8483 * channel-open procedure and just pass the message on
8486 share_got_pkt_from_server(realpf->share_ctx, pktin->type,
8487 pktin->body, pktin->length);
8492 err = pfd_connect(&c->u.pfd.pf, realpf->dhost, realpf->dport,
8493 c, ssh->conf, realpf->pfrec->addressfamily);
8494 logeventf(ssh, "Attempting to forward remote port to "
8495 "%s:%d", realpf->dhost, realpf->dport);
8497 logeventf(ssh, "Port open failed: %s", err);
8499 error = "Port open failed";
8501 logevent("Forwarded port opened successfully");
8502 c->type = CHAN_SOCKDATA;
8505 } else if (typelen == 22 &&
8506 !memcmp(type, "auth-agent@openssh.com", 22)) {
8507 if (!ssh->agentfwd_enabled)
8508 error = "Agent forwarding is not enabled";
8510 c->type = CHAN_AGENT; /* identify channel type */
8511 c->u.a.lensofar = 0;
8512 c->u.a.message = NULL;
8513 c->u.a.outstanding_requests = 0;
8516 error = "Unsupported channel type requested";
8519 c->remoteid = remid;
8520 c->halfopen = FALSE;
8522 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_FAILURE);
8523 ssh2_pkt_adduint32(pktout, c->remoteid);
8524 ssh2_pkt_adduint32(pktout, SSH2_OPEN_CONNECT_FAILED);
8525 ssh2_pkt_addstring(pktout, error);
8526 ssh2_pkt_addstring(pktout, "en"); /* language tag */
8527 ssh2_pkt_send(ssh, pktout);
8528 logeventf(ssh, "Rejected channel open: %s", error);
8531 ssh2_channel_init(c);
8532 c->v.v2.remwindow = winsize;
8533 c->v.v2.remmaxpkt = pktsize;
8534 if (our_winsize_override) {
8535 c->v.v2.locwindow = c->v.v2.locmaxwin = c->v.v2.remlocwin =
8536 our_winsize_override;
8538 add234(ssh->channels, c);
8539 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
8540 ssh2_pkt_adduint32(pktout, c->remoteid);
8541 ssh2_pkt_adduint32(pktout, c->localid);
8542 ssh2_pkt_adduint32(pktout, c->v.v2.locwindow);
8543 ssh2_pkt_adduint32(pktout, OUR_V2_MAXPKT); /* our max pkt size */
8544 ssh2_pkt_send(ssh, pktout);
8548 void sshfwd_x11_sharing_handover(struct ssh_channel *c,
8549 void *share_cs, void *share_chan,
8550 const char *peer_addr, int peer_port,
8551 int endian, int protomajor, int protominor,
8552 const void *initial_data, int initial_len)
8555 * This function is called when we've just discovered that an X
8556 * forwarding channel on which we'd been handling the initial auth
8557 * ourselves turns out to be destined for a connection-sharing
8558 * downstream. So we turn the channel into a CHAN_SHARING, meaning
8559 * that we completely stop tracking windows and buffering data and
8560 * just pass more or less unmodified SSH messages back and forth.
8562 c->type = CHAN_SHARING;
8563 c->u.sharing.ctx = share_cs;
8564 share_setup_x11_channel(share_cs, share_chan,
8565 c->localid, c->remoteid, c->v.v2.remwindow,
8566 c->v.v2.remmaxpkt, c->v.v2.locwindow,
8567 peer_addr, peer_port, endian,
8568 protomajor, protominor,
8569 initial_data, initial_len);
8572 void sshfwd_x11_is_local(struct ssh_channel *c)
8575 * This function is called when we've just discovered that an X
8576 * forwarding channel is _not_ destined for a connection-sharing
8577 * downstream but we're going to handle it ourselves. We stop
8578 * presenting a cautiously small window and go into ordinary data
8581 c->u.x11.initial = FALSE;
8582 ssh2_set_window(c, ssh_is_simple(c->ssh) ? OUR_V2_BIGWIN : OUR_V2_WINSIZE);
8586 * Buffer banner messages for later display at some convenient point,
8587 * if we're going to display them.
8589 static void ssh2_msg_userauth_banner(Ssh ssh, struct Packet *pktin)
8591 /* Arbitrary limit to prevent unbounded inflation of buffer */
8592 if (conf_get_int(ssh->conf, CONF_ssh_show_banner) &&
8593 bufchain_size(&ssh->banner) <= 131072) {
8594 char *banner = NULL;
8596 ssh_pkt_getstring(pktin, &banner, &size);
8598 bufchain_add(&ssh->banner, banner, size);
8602 /* Helper function to deal with sending tty modes for "pty-req" */
8603 static void ssh2_send_ttymode(void *data, char *mode, char *val)
8605 struct Packet *pktout = (struct Packet *)data;
8607 unsigned int arg = 0;
8608 while (strcmp(mode, ssh_ttymodes[i].mode) != 0) i++;
8609 if (i == lenof(ssh_ttymodes)) return;
8610 switch (ssh_ttymodes[i].type) {
8612 arg = ssh_tty_parse_specchar(val);
8615 arg = ssh_tty_parse_boolean(val);
8618 ssh2_pkt_addbyte(pktout, ssh_ttymodes[i].opcode);
8619 ssh2_pkt_adduint32(pktout, arg);
8622 static void ssh2_setup_x11(struct ssh_channel *c, struct Packet *pktin,
8625 struct ssh2_setup_x11_state {
8629 struct Packet *pktout;
8630 crStateP(ssh2_setup_x11_state, ctx);
8634 logevent("Requesting X11 forwarding");
8635 pktout = ssh2_chanreq_init(ssh->mainchan, "x11-req",
8637 ssh2_pkt_addbool(pktout, 0); /* many connections */
8638 ssh2_pkt_addstring(pktout, ssh->x11auth->protoname);
8639 ssh2_pkt_addstring(pktout, ssh->x11auth->datastring);
8640 ssh2_pkt_adduint32(pktout, ssh->x11disp->screennum);
8641 ssh2_pkt_send(ssh, pktout);
8643 /* Wait to be called back with either a response packet, or NULL
8644 * meaning clean up and free our data */
8648 if (pktin->type == SSH2_MSG_CHANNEL_SUCCESS) {
8649 logevent("X11 forwarding enabled");
8650 ssh->X11_fwd_enabled = TRUE;
8652 logevent("X11 forwarding refused");
8658 static void ssh2_setup_agent(struct ssh_channel *c, struct Packet *pktin,
8661 struct ssh2_setup_agent_state {
8665 struct Packet *pktout;
8666 crStateP(ssh2_setup_agent_state, ctx);
8670 logevent("Requesting OpenSSH-style agent forwarding");
8671 pktout = ssh2_chanreq_init(ssh->mainchan, "auth-agent-req@openssh.com",
8672 ssh2_setup_agent, s);
8673 ssh2_pkt_send(ssh, pktout);
8675 /* Wait to be called back with either a response packet, or NULL
8676 * meaning clean up and free our data */
8680 if (pktin->type == SSH2_MSG_CHANNEL_SUCCESS) {
8681 logevent("Agent forwarding enabled");
8682 ssh->agentfwd_enabled = TRUE;
8684 logevent("Agent forwarding refused");
8690 static void ssh2_setup_pty(struct ssh_channel *c, struct Packet *pktin,
8693 struct ssh2_setup_pty_state {
8697 struct Packet *pktout;
8698 crStateP(ssh2_setup_pty_state, ctx);
8702 /* Unpick the terminal-speed string. */
8703 /* XXX perhaps we should allow no speeds to be sent. */
8704 ssh->ospeed = 38400; ssh->ispeed = 38400; /* last-resort defaults */
8705 sscanf(conf_get_str(ssh->conf, CONF_termspeed), "%d,%d", &ssh->ospeed, &ssh->ispeed);
8706 /* Build the pty request. */
8707 pktout = ssh2_chanreq_init(ssh->mainchan, "pty-req",
8709 ssh2_pkt_addstring(pktout, conf_get_str(ssh->conf, CONF_termtype));
8710 ssh2_pkt_adduint32(pktout, ssh->term_width);
8711 ssh2_pkt_adduint32(pktout, ssh->term_height);
8712 ssh2_pkt_adduint32(pktout, 0); /* pixel width */
8713 ssh2_pkt_adduint32(pktout, 0); /* pixel height */
8714 ssh2_pkt_addstring_start(pktout);
8715 parse_ttymodes(ssh, ssh2_send_ttymode, (void *)pktout);
8716 ssh2_pkt_addbyte(pktout, SSH2_TTY_OP_ISPEED);
8717 ssh2_pkt_adduint32(pktout, ssh->ispeed);
8718 ssh2_pkt_addbyte(pktout, SSH2_TTY_OP_OSPEED);
8719 ssh2_pkt_adduint32(pktout, ssh->ospeed);
8720 ssh2_pkt_addstring_data(pktout, "\0", 1); /* TTY_OP_END */
8721 ssh2_pkt_send(ssh, pktout);
8722 ssh->state = SSH_STATE_INTERMED;
8724 /* Wait to be called back with either a response packet, or NULL
8725 * meaning clean up and free our data */
8729 if (pktin->type == SSH2_MSG_CHANNEL_SUCCESS) {
8730 logeventf(ssh, "Allocated pty (ospeed %dbps, ispeed %dbps)",
8731 ssh->ospeed, ssh->ispeed);
8732 ssh->got_pty = TRUE;
8734 c_write_str(ssh, "Server refused to allocate pty\r\n");
8735 ssh->editing = ssh->echoing = 1;
8742 static void ssh2_setup_env(struct ssh_channel *c, struct Packet *pktin,
8745 struct ssh2_setup_env_state {
8747 int num_env, env_left, env_ok;
8750 struct Packet *pktout;
8751 crStateP(ssh2_setup_env_state, ctx);
8756 * Send environment variables.
8758 * Simplest thing here is to send all the requests at once, and
8759 * then wait for a whole bunch of successes or failures.
8765 for (val = conf_get_str_strs(ssh->conf, CONF_environmt, NULL, &key);
8767 val = conf_get_str_strs(ssh->conf, CONF_environmt, key, &key)) {
8768 pktout = ssh2_chanreq_init(ssh->mainchan, "env", ssh2_setup_env, s);
8769 ssh2_pkt_addstring(pktout, key);
8770 ssh2_pkt_addstring(pktout, val);
8771 ssh2_pkt_send(ssh, pktout);
8776 logeventf(ssh, "Sent %d environment variables", s->num_env);
8781 s->env_left = s->num_env;
8783 while (s->env_left > 0) {
8784 /* Wait to be called back with either a response packet,
8785 * or NULL meaning clean up and free our data */
8787 if (!pktin) goto out;
8788 if (pktin->type == SSH2_MSG_CHANNEL_SUCCESS)
8793 if (s->env_ok == s->num_env) {
8794 logevent("All environment variables successfully set");
8795 } else if (s->env_ok == 0) {
8796 logevent("All environment variables refused");
8797 c_write_str(ssh, "Server refused to set environment variables\r\n");
8799 logeventf(ssh, "%d environment variables refused",
8800 s->num_env - s->env_ok);
8801 c_write_str(ssh, "Server refused to set all environment variables\r\n");
8809 * Handle the SSH-2 userauth and connection layers.
8811 static void ssh2_msg_authconn(Ssh ssh, struct Packet *pktin)
8813 do_ssh2_authconn(ssh, NULL, 0, pktin);
8816 static void ssh2_response_authconn(struct ssh_channel *c, struct Packet *pktin,
8820 do_ssh2_authconn(c->ssh, NULL, 0, pktin);
8823 static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
8824 struct Packet *pktin)
8826 struct do_ssh2_authconn_state {
8830 AUTH_TYPE_PUBLICKEY,
8831 AUTH_TYPE_PUBLICKEY_OFFER_LOUD,
8832 AUTH_TYPE_PUBLICKEY_OFFER_QUIET,
8834 AUTH_TYPE_GSSAPI, /* always QUIET */
8835 AUTH_TYPE_KEYBOARD_INTERACTIVE,
8836 AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET
8838 int done_service_req;
8839 int gotit, need_pw, can_pubkey, can_passwd, can_keyb_inter;
8840 int tried_pubkey_config, done_agent;
8845 int kbd_inter_refused;
8846 int we_are_in, userauth_success;
8847 prompts_t *cur_prompt;
8852 void *publickey_blob;
8853 int publickey_bloblen;
8854 int publickey_encrypted;
8855 char *publickey_algorithm;
8856 char *publickey_comment;
8857 unsigned char agent_request[5], *agent_response, *agentp;
8858 int agent_responselen;
8859 unsigned char *pkblob_in_agent;
8861 char *pkblob, *alg, *commentp;
8862 int pklen, alglen, commentlen;
8863 int siglen, retlen, len;
8864 char *q, *agentreq, *ret;
8866 struct Packet *pktout;
8869 struct ssh_gss_library *gsslib;
8870 Ssh_gss_ctx gss_ctx;
8871 Ssh_gss_buf gss_buf;
8872 Ssh_gss_buf gss_rcvtok, gss_sndtok;
8873 Ssh_gss_name gss_srv_name;
8874 Ssh_gss_stat gss_stat;
8877 crState(do_ssh2_authconn_state);
8881 /* Register as a handler for all the messages this coroutine handles. */
8882 ssh->packet_dispatch[SSH2_MSG_SERVICE_ACCEPT] = ssh2_msg_authconn;
8883 ssh->packet_dispatch[SSH2_MSG_USERAUTH_REQUEST] = ssh2_msg_authconn;
8884 ssh->packet_dispatch[SSH2_MSG_USERAUTH_FAILURE] = ssh2_msg_authconn;
8885 ssh->packet_dispatch[SSH2_MSG_USERAUTH_SUCCESS] = ssh2_msg_authconn;
8886 ssh->packet_dispatch[SSH2_MSG_USERAUTH_BANNER] = ssh2_msg_authconn;
8887 ssh->packet_dispatch[SSH2_MSG_USERAUTH_PK_OK] = ssh2_msg_authconn;
8888 /* ssh->packet_dispatch[SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ] = ssh2_msg_authconn; duplicate case value */
8889 /* ssh->packet_dispatch[SSH2_MSG_USERAUTH_INFO_REQUEST] = ssh2_msg_authconn; duplicate case value */
8890 ssh->packet_dispatch[SSH2_MSG_USERAUTH_INFO_RESPONSE] = ssh2_msg_authconn;
8891 ssh->packet_dispatch[SSH2_MSG_GLOBAL_REQUEST] = ssh2_msg_authconn;
8892 ssh->packet_dispatch[SSH2_MSG_REQUEST_SUCCESS] = ssh2_msg_authconn;
8893 ssh->packet_dispatch[SSH2_MSG_REQUEST_FAILURE] = ssh2_msg_authconn;
8894 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN] = ssh2_msg_authconn;
8895 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_CONFIRMATION] = ssh2_msg_authconn;
8896 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_FAILURE] = ssh2_msg_authconn;
8897 ssh->packet_dispatch[SSH2_MSG_CHANNEL_WINDOW_ADJUST] = ssh2_msg_authconn;
8898 ssh->packet_dispatch[SSH2_MSG_CHANNEL_DATA] = ssh2_msg_authconn;
8899 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EXTENDED_DATA] = ssh2_msg_authconn;
8900 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EOF] = ssh2_msg_authconn;
8901 ssh->packet_dispatch[SSH2_MSG_CHANNEL_CLOSE] = ssh2_msg_authconn;
8903 s->done_service_req = FALSE;
8904 s->we_are_in = s->userauth_success = FALSE;
8905 s->agent_response = NULL;
8907 s->tried_gssapi = FALSE;
8910 if (!ssh->bare_connection) {
8911 if (!conf_get_int(ssh->conf, CONF_ssh_no_userauth)) {
8913 * Request userauth protocol, and await a response to it.
8915 s->pktout = ssh2_pkt_init(SSH2_MSG_SERVICE_REQUEST);
8916 ssh2_pkt_addstring(s->pktout, "ssh-userauth");
8917 ssh2_pkt_send(ssh, s->pktout);
8918 crWaitUntilV(pktin);
8919 if (pktin->type == SSH2_MSG_SERVICE_ACCEPT)
8920 s->done_service_req = TRUE;
8922 if (!s->done_service_req) {
8924 * Request connection protocol directly, without authentication.
8926 s->pktout = ssh2_pkt_init(SSH2_MSG_SERVICE_REQUEST);
8927 ssh2_pkt_addstring(s->pktout, "ssh-connection");
8928 ssh2_pkt_send(ssh, s->pktout);
8929 crWaitUntilV(pktin);
8930 if (pktin->type == SSH2_MSG_SERVICE_ACCEPT) {
8931 s->we_are_in = TRUE; /* no auth required */
8933 bombout(("Server refused service request"));
8938 s->we_are_in = TRUE;
8941 /* Arrange to be able to deal with any BANNERs that come in.
8942 * (We do this now as packets may come in during the next bit.) */
8943 bufchain_init(&ssh->banner);
8944 ssh->packet_dispatch[SSH2_MSG_USERAUTH_BANNER] =
8945 ssh2_msg_userauth_banner;
8948 * Misc one-time setup for authentication.
8950 s->publickey_blob = NULL;
8951 if (!s->we_are_in) {
8954 * Load the public half of any configured public key file
8957 s->keyfile = conf_get_filename(ssh->conf, CONF_keyfile);
8958 if (!filename_is_null(s->keyfile)) {
8960 logeventf(ssh, "Reading private key file \"%.150s\"",
8961 filename_to_str(s->keyfile));
8962 keytype = key_type(s->keyfile);
8963 if (keytype == SSH_KEYTYPE_SSH2) {
8966 ssh2_userkey_loadpub(s->keyfile,
8967 &s->publickey_algorithm,
8968 &s->publickey_bloblen,
8969 &s->publickey_comment, &error);
8970 if (s->publickey_blob) {
8971 s->publickey_encrypted =
8972 ssh2_userkey_encrypted(s->keyfile, NULL);
8975 logeventf(ssh, "Unable to load private key (%s)",
8977 msgbuf = dupprintf("Unable to load private key file "
8978 "\"%.150s\" (%s)\r\n",
8979 filename_to_str(s->keyfile),
8981 c_write_str(ssh, msgbuf);
8986 logeventf(ssh, "Unable to use this key file (%s)",
8987 key_type_to_str(keytype));
8988 msgbuf = dupprintf("Unable to use key file \"%.150s\""
8990 filename_to_str(s->keyfile),
8991 key_type_to_str(keytype));
8992 c_write_str(ssh, msgbuf);
8994 s->publickey_blob = NULL;
8999 * Find out about any keys Pageant has (but if there's a
9000 * public key configured, filter out all others).
9003 s->agent_response = NULL;
9004 s->pkblob_in_agent = NULL;
9005 if (conf_get_int(ssh->conf, CONF_tryagent) && agent_exists()) {
9009 logevent("Pageant is running. Requesting keys.");
9011 /* Request the keys held by the agent. */
9012 PUT_32BIT(s->agent_request, 1);
9013 s->agent_request[4] = SSH2_AGENTC_REQUEST_IDENTITIES;
9014 if (!agent_query(s->agent_request, 5, &r, &s->agent_responselen,
9015 ssh_agent_callback, ssh)) {
9019 bombout(("Unexpected data from server while"
9020 " waiting for agent response"));
9023 } while (pktin || inlen > 0);
9024 r = ssh->agent_response;
9025 s->agent_responselen = ssh->agent_response_len;
9027 s->agent_response = (unsigned char *) r;
9028 if (s->agent_response && s->agent_responselen >= 5 &&
9029 s->agent_response[4] == SSH2_AGENT_IDENTITIES_ANSWER) {
9032 p = s->agent_response + 5;
9033 s->nkeys = toint(GET_32BIT(p));
9036 * Vet the Pageant response to ensure that the key
9037 * count and blob lengths make sense.
9040 logeventf(ssh, "Pageant response contained a negative"
9041 " key count %d", s->nkeys);
9043 goto done_agent_query;
9045 unsigned char *q = p + 4;
9046 int lenleft = s->agent_responselen - 5 - 4;
9048 for (keyi = 0; keyi < s->nkeys; keyi++) {
9049 int bloblen, commentlen;
9051 logeventf(ssh, "Pageant response was truncated");
9053 goto done_agent_query;
9055 bloblen = toint(GET_32BIT(q));
9056 if (bloblen < 0 || bloblen > lenleft) {
9057 logeventf(ssh, "Pageant response was truncated");
9059 goto done_agent_query;
9061 lenleft -= 4 + bloblen;
9063 commentlen = toint(GET_32BIT(q));
9064 if (commentlen < 0 || commentlen > lenleft) {
9065 logeventf(ssh, "Pageant response was truncated");
9067 goto done_agent_query;
9069 lenleft -= 4 + commentlen;
9070 q += 4 + commentlen;
9075 logeventf(ssh, "Pageant has %d SSH-2 keys", s->nkeys);
9076 if (s->publickey_blob) {
9077 /* See if configured key is in agent. */
9078 for (keyi = 0; keyi < s->nkeys; keyi++) {
9079 s->pklen = toint(GET_32BIT(p));
9080 if (s->pklen == s->publickey_bloblen &&
9081 !memcmp(p+4, s->publickey_blob,
9082 s->publickey_bloblen)) {
9083 logeventf(ssh, "Pageant key #%d matches "
9084 "configured key file", keyi);
9086 s->pkblob_in_agent = p;
9090 p += toint(GET_32BIT(p)) + 4; /* comment */
9092 if (!s->pkblob_in_agent) {
9093 logevent("Configured key file not in Pageant");
9098 logevent("Failed to get reply from Pageant");
9106 * We repeat this whole loop, including the username prompt,
9107 * until we manage a successful authentication. If the user
9108 * types the wrong _password_, they can be sent back to the
9109 * beginning to try another username, if this is configured on.
9110 * (If they specify a username in the config, they are never
9111 * asked, even if they do give a wrong password.)
9113 * I think this best serves the needs of
9115 * - the people who have no configuration, no keys, and just
9116 * want to try repeated (username,password) pairs until they
9117 * type both correctly
9119 * - people who have keys and configuration but occasionally
9120 * need to fall back to passwords
9122 * - people with a key held in Pageant, who might not have
9123 * logged in to a particular machine before; so they want to
9124 * type a username, and then _either_ their key will be
9125 * accepted, _or_ they will type a password. If they mistype
9126 * the username they will want to be able to get back and
9129 s->got_username = FALSE;
9130 while (!s->we_are_in) {
9134 if (s->got_username && !conf_get_int(ssh->conf, CONF_change_username)) {
9136 * We got a username last time round this loop, and
9137 * with change_username turned off we don't try to get
9140 } else if ((ssh->username = get_remote_username(ssh->conf)) == NULL) {
9141 int ret; /* need not be kept over crReturn */
9142 s->cur_prompt = new_prompts(ssh->frontend);
9143 s->cur_prompt->to_server = TRUE;
9144 s->cur_prompt->name = dupstr("SSH login name");
9145 add_prompt(s->cur_prompt, dupstr("login as: "), TRUE);
9146 ret = get_userpass_input(s->cur_prompt, NULL, 0);
9149 crWaitUntilV(!pktin);
9150 ret = get_userpass_input(s->cur_prompt, in, inlen);
9155 * get_userpass_input() failed to get a username.
9158 free_prompts(s->cur_prompt);
9159 ssh_disconnect(ssh, "No username provided", NULL, 0, TRUE);
9162 ssh->username = dupstr(s->cur_prompt->prompts[0]->result);
9163 free_prompts(s->cur_prompt);
9166 if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
9167 stuff = dupprintf("Using username \"%s\".\r\n", ssh->username);
9168 c_write_str(ssh, stuff);
9172 s->got_username = TRUE;
9175 * Send an authentication request using method "none": (a)
9176 * just in case it succeeds, and (b) so that we know what
9177 * authentication methods we can usefully try next.
9179 ssh->pkt_actx = SSH2_PKTCTX_NOAUTH;
9181 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9182 ssh2_pkt_addstring(s->pktout, ssh->username);
9183 ssh2_pkt_addstring(s->pktout, "ssh-connection");/* service requested */
9184 ssh2_pkt_addstring(s->pktout, "none"); /* method */
9185 ssh2_pkt_send(ssh, s->pktout);
9186 s->type = AUTH_TYPE_NONE;
9188 s->we_are_in = FALSE;
9190 s->tried_pubkey_config = FALSE;
9191 s->kbd_inter_refused = FALSE;
9193 /* Reset agent request state. */
9194 s->done_agent = FALSE;
9195 if (s->agent_response) {
9196 if (s->pkblob_in_agent) {
9197 s->agentp = s->pkblob_in_agent;
9199 s->agentp = s->agent_response + 5 + 4;
9205 char *methods = NULL;
9209 * Wait for the result of the last authentication request.
9212 crWaitUntilV(pktin);
9214 * Now is a convenient point to spew any banner material
9215 * that we've accumulated. (This should ensure that when
9216 * we exit the auth loop, we haven't any left to deal
9220 int size = bufchain_size(&ssh->banner);
9222 * Don't show the banner if we're operating in
9223 * non-verbose non-interactive mode. (It's probably
9224 * a script, which means nobody will read the
9225 * banner _anyway_, and moreover the printing of
9226 * the banner will screw up processing on the
9227 * output of (say) plink.)
9229 if (size && (flags & (FLAG_VERBOSE | FLAG_INTERACTIVE))) {
9230 char *banner = snewn(size, char);
9231 bufchain_fetch(&ssh->banner, banner, size);
9232 c_write_untrusted(ssh, banner, size);
9235 bufchain_clear(&ssh->banner);
9237 if (pktin->type == SSH2_MSG_USERAUTH_SUCCESS) {
9238 logevent("Access granted");
9239 s->we_are_in = s->userauth_success = TRUE;
9243 if (pktin->type != SSH2_MSG_USERAUTH_FAILURE && s->type != AUTH_TYPE_GSSAPI) {
9244 bombout(("Strange packet received during authentication: "
9245 "type %d", pktin->type));
9252 * OK, we're now sitting on a USERAUTH_FAILURE message, so
9253 * we can look at the string in it and know what we can
9254 * helpfully try next.
9256 if (pktin->type == SSH2_MSG_USERAUTH_FAILURE) {
9257 ssh_pkt_getstring(pktin, &methods, &methlen);
9258 if (!ssh2_pkt_getbool(pktin)) {
9260 * We have received an unequivocal Access
9261 * Denied. This can translate to a variety of
9262 * messages, or no message at all.
9264 * For forms of authentication which are attempted
9265 * implicitly, by which I mean without printing
9266 * anything in the window indicating that we're
9267 * trying them, we should never print 'Access
9270 * If we do print a message saying that we're
9271 * attempting some kind of authentication, it's OK
9272 * to print a followup message saying it failed -
9273 * but the message may sometimes be more specific
9274 * than simply 'Access denied'.
9276 * Additionally, if we'd just tried password
9277 * authentication, we should break out of this
9278 * whole loop so as to go back to the username
9279 * prompt (iff we're configured to allow
9280 * username change attempts).
9282 if (s->type == AUTH_TYPE_NONE) {
9284 } else if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD ||
9285 s->type == AUTH_TYPE_PUBLICKEY_OFFER_QUIET) {
9286 if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD)
9287 c_write_str(ssh, "Server refused our key\r\n");
9288 logevent("Server refused our key");
9289 } else if (s->type == AUTH_TYPE_PUBLICKEY) {
9290 /* This _shouldn't_ happen except by a
9291 * protocol bug causing client and server to
9292 * disagree on what is a correct signature. */
9293 c_write_str(ssh, "Server refused public-key signature"
9294 " despite accepting key!\r\n");
9295 logevent("Server refused public-key signature"
9296 " despite accepting key!");
9297 } else if (s->type==AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET) {
9298 /* quiet, so no c_write */
9299 logevent("Server refused keyboard-interactive authentication");
9300 } else if (s->type==AUTH_TYPE_GSSAPI) {
9301 /* always quiet, so no c_write */
9302 /* also, the code down in the GSSAPI block has
9303 * already logged this in the Event Log */
9304 } else if (s->type == AUTH_TYPE_KEYBOARD_INTERACTIVE) {
9305 logevent("Keyboard-interactive authentication failed");
9306 c_write_str(ssh, "Access denied\r\n");
9308 assert(s->type == AUTH_TYPE_PASSWORD);
9309 logevent("Password authentication failed");
9310 c_write_str(ssh, "Access denied\r\n");
9312 if (conf_get_int(ssh->conf, CONF_change_username)) {
9313 /* XXX perhaps we should allow
9314 * keyboard-interactive to do this too? */
9315 s->we_are_in = FALSE;
9320 c_write_str(ssh, "Further authentication required\r\n");
9321 logevent("Further authentication required");
9325 in_commasep_string("publickey", methods, methlen);
9327 in_commasep_string("password", methods, methlen);
9328 s->can_keyb_inter = conf_get_int(ssh->conf, CONF_try_ki_auth) &&
9329 in_commasep_string("keyboard-interactive", methods, methlen);
9332 ssh->gsslibs = ssh_gss_setup(ssh->conf);
9333 s->can_gssapi = conf_get_int(ssh->conf, CONF_try_gssapi_auth) &&
9334 in_commasep_string("gssapi-with-mic", methods, methlen) &&
9335 ssh->gsslibs->nlibraries > 0;
9339 ssh->pkt_actx = SSH2_PKTCTX_NOAUTH;
9341 if (s->can_pubkey && !s->done_agent && s->nkeys) {
9344 * Attempt public-key authentication using a key from Pageant.
9347 ssh->pkt_actx = SSH2_PKTCTX_PUBLICKEY;
9349 logeventf(ssh, "Trying Pageant key #%d", s->keyi);
9351 /* Unpack key from agent response */
9352 s->pklen = toint(GET_32BIT(s->agentp));
9354 s->pkblob = (char *)s->agentp;
9355 s->agentp += s->pklen;
9356 s->alglen = toint(GET_32BIT(s->pkblob));
9357 s->alg = s->pkblob + 4;
9358 s->commentlen = toint(GET_32BIT(s->agentp));
9360 s->commentp = (char *)s->agentp;
9361 s->agentp += s->commentlen;
9362 /* s->agentp now points at next key, if any */
9364 /* See if server will accept it */
9365 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9366 ssh2_pkt_addstring(s->pktout, ssh->username);
9367 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9368 /* service requested */
9369 ssh2_pkt_addstring(s->pktout, "publickey");
9371 ssh2_pkt_addbool(s->pktout, FALSE); /* no signature included */
9372 ssh2_pkt_addstring_start(s->pktout);
9373 ssh2_pkt_addstring_data(s->pktout, s->alg, s->alglen);
9374 ssh2_pkt_addstring_start(s->pktout);
9375 ssh2_pkt_addstring_data(s->pktout, s->pkblob, s->pklen);
9376 ssh2_pkt_send(ssh, s->pktout);
9377 s->type = AUTH_TYPE_PUBLICKEY_OFFER_QUIET;
9379 crWaitUntilV(pktin);
9380 if (pktin->type != SSH2_MSG_USERAUTH_PK_OK) {
9382 /* Offer of key refused. */
9389 if (flags & FLAG_VERBOSE) {
9390 c_write_str(ssh, "Authenticating with "
9392 c_write(ssh, s->commentp, s->commentlen);
9393 c_write_str(ssh, "\" from agent\r\n");
9397 * Server is willing to accept the key.
9398 * Construct a SIGN_REQUEST.
9400 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9401 ssh2_pkt_addstring(s->pktout, ssh->username);
9402 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9403 /* service requested */
9404 ssh2_pkt_addstring(s->pktout, "publickey");
9406 ssh2_pkt_addbool(s->pktout, TRUE); /* signature included */
9407 ssh2_pkt_addstring_start(s->pktout);
9408 ssh2_pkt_addstring_data(s->pktout, s->alg, s->alglen);
9409 ssh2_pkt_addstring_start(s->pktout);
9410 ssh2_pkt_addstring_data(s->pktout, s->pkblob, s->pklen);
9412 /* Ask agent for signature. */
9413 s->siglen = s->pktout->length - 5 + 4 +
9414 ssh->v2_session_id_len;
9415 if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
9417 s->len = 1; /* message type */
9418 s->len += 4 + s->pklen; /* key blob */
9419 s->len += 4 + s->siglen; /* data to sign */
9420 s->len += 4; /* flags */
9421 s->agentreq = snewn(4 + s->len, char);
9422 PUT_32BIT(s->agentreq, s->len);
9423 s->q = s->agentreq + 4;
9424 *s->q++ = SSH2_AGENTC_SIGN_REQUEST;
9425 PUT_32BIT(s->q, s->pklen);
9427 memcpy(s->q, s->pkblob, s->pklen);
9429 PUT_32BIT(s->q, s->siglen);
9431 /* Now the data to be signed... */
9432 if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
9433 PUT_32BIT(s->q, ssh->v2_session_id_len);
9436 memcpy(s->q, ssh->v2_session_id,
9437 ssh->v2_session_id_len);
9438 s->q += ssh->v2_session_id_len;
9439 memcpy(s->q, s->pktout->data + 5,
9440 s->pktout->length - 5);
9441 s->q += s->pktout->length - 5;
9442 /* And finally the (zero) flags word. */
9444 if (!agent_query(s->agentreq, s->len + 4,
9446 ssh_agent_callback, ssh)) {
9450 bombout(("Unexpected data from server"
9451 " while waiting for agent"
9455 } while (pktin || inlen > 0);
9456 vret = ssh->agent_response;
9457 s->retlen = ssh->agent_response_len;
9462 if (s->retlen >= 9 &&
9463 s->ret[4] == SSH2_AGENT_SIGN_RESPONSE &&
9464 GET_32BIT(s->ret + 5) <= (unsigned)(s->retlen-9)) {
9465 logevent("Sending Pageant's response");
9466 ssh2_add_sigblob(ssh, s->pktout,
9467 s->pkblob, s->pklen,
9469 GET_32BIT(s->ret + 5));
9470 ssh2_pkt_send(ssh, s->pktout);
9471 s->type = AUTH_TYPE_PUBLICKEY;
9473 /* FIXME: less drastic response */
9474 bombout(("Pageant failed to answer challenge"));
9480 /* Do we have any keys left to try? */
9481 if (s->pkblob_in_agent) {
9482 s->done_agent = TRUE;
9483 s->tried_pubkey_config = TRUE;
9486 if (s->keyi >= s->nkeys)
9487 s->done_agent = TRUE;
9490 } else if (s->can_pubkey && s->publickey_blob &&
9491 !s->tried_pubkey_config) {
9493 struct ssh2_userkey *key; /* not live over crReturn */
9494 char *passphrase; /* not live over crReturn */
9496 ssh->pkt_actx = SSH2_PKTCTX_PUBLICKEY;
9498 s->tried_pubkey_config = TRUE;
9501 * Try the public key supplied in the configuration.
9503 * First, offer the public blob to see if the server is
9504 * willing to accept it.
9506 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9507 ssh2_pkt_addstring(s->pktout, ssh->username);
9508 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9509 /* service requested */
9510 ssh2_pkt_addstring(s->pktout, "publickey"); /* method */
9511 ssh2_pkt_addbool(s->pktout, FALSE);
9512 /* no signature included */
9513 ssh2_pkt_addstring(s->pktout, s->publickey_algorithm);
9514 ssh2_pkt_addstring_start(s->pktout);
9515 ssh2_pkt_addstring_data(s->pktout,
9516 (char *)s->publickey_blob,
9517 s->publickey_bloblen);
9518 ssh2_pkt_send(ssh, s->pktout);
9519 logevent("Offered public key");
9521 crWaitUntilV(pktin);
9522 if (pktin->type != SSH2_MSG_USERAUTH_PK_OK) {
9523 /* Key refused. Give up. */
9524 s->gotit = TRUE; /* reconsider message next loop */
9525 s->type = AUTH_TYPE_PUBLICKEY_OFFER_LOUD;
9526 continue; /* process this new message */
9528 logevent("Offer of public key accepted");
9531 * Actually attempt a serious authentication using
9534 if (flags & FLAG_VERBOSE) {
9535 c_write_str(ssh, "Authenticating with public key \"");
9536 c_write_str(ssh, s->publickey_comment);
9537 c_write_str(ssh, "\"\r\n");
9541 const char *error; /* not live over crReturn */
9542 if (s->publickey_encrypted) {
9544 * Get a passphrase from the user.
9546 int ret; /* need not be kept over crReturn */
9547 s->cur_prompt = new_prompts(ssh->frontend);
9548 s->cur_prompt->to_server = FALSE;
9549 s->cur_prompt->name = dupstr("SSH key passphrase");
9550 add_prompt(s->cur_prompt,
9551 dupprintf("Passphrase for key \"%.100s\": ",
9552 s->publickey_comment),
9554 ret = get_userpass_input(s->cur_prompt, NULL, 0);
9557 crWaitUntilV(!pktin);
9558 ret = get_userpass_input(s->cur_prompt,
9563 /* Failed to get a passphrase. Terminate. */
9564 free_prompts(s->cur_prompt);
9565 ssh_disconnect(ssh, NULL,
9566 "Unable to authenticate",
9567 SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER,
9572 dupstr(s->cur_prompt->prompts[0]->result);
9573 free_prompts(s->cur_prompt);
9575 passphrase = NULL; /* no passphrase needed */
9579 * Try decrypting the key.
9581 s->keyfile = conf_get_filename(ssh->conf, CONF_keyfile);
9582 key = ssh2_load_userkey(s->keyfile, passphrase, &error);
9584 /* burn the evidence */
9585 smemclr(passphrase, strlen(passphrase));
9588 if (key == SSH2_WRONG_PASSPHRASE || key == NULL) {
9590 (key == SSH2_WRONG_PASSPHRASE)) {
9591 c_write_str(ssh, "Wrong passphrase\r\n");
9593 /* and loop again */
9595 c_write_str(ssh, "Unable to load private key (");
9596 c_write_str(ssh, error);
9597 c_write_str(ssh, ")\r\n");
9599 break; /* try something else */
9605 unsigned char *pkblob, *sigblob, *sigdata;
9606 int pkblob_len, sigblob_len, sigdata_len;
9610 * We have loaded the private key and the server
9611 * has announced that it's willing to accept it.
9612 * Hallelujah. Generate a signature and send it.
9614 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9615 ssh2_pkt_addstring(s->pktout, ssh->username);
9616 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9617 /* service requested */
9618 ssh2_pkt_addstring(s->pktout, "publickey");
9620 ssh2_pkt_addbool(s->pktout, TRUE);
9621 /* signature follows */
9622 ssh2_pkt_addstring(s->pktout, key->alg->name);
9623 pkblob = key->alg->public_blob(key->data,
9625 ssh2_pkt_addstring_start(s->pktout);
9626 ssh2_pkt_addstring_data(s->pktout, (char *)pkblob,
9630 * The data to be signed is:
9634 * followed by everything so far placed in the
9637 sigdata_len = s->pktout->length - 5 + 4 +
9638 ssh->v2_session_id_len;
9639 if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
9641 sigdata = snewn(sigdata_len, unsigned char);
9643 if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
9644 PUT_32BIT(sigdata+p, ssh->v2_session_id_len);
9647 memcpy(sigdata+p, ssh->v2_session_id,
9648 ssh->v2_session_id_len);
9649 p += ssh->v2_session_id_len;
9650 memcpy(sigdata+p, s->pktout->data + 5,
9651 s->pktout->length - 5);
9652 p += s->pktout->length - 5;
9653 assert(p == sigdata_len);
9654 sigblob = key->alg->sign(key->data, (char *)sigdata,
9655 sigdata_len, &sigblob_len);
9656 ssh2_add_sigblob(ssh, s->pktout, pkblob, pkblob_len,
9657 sigblob, sigblob_len);
9662 ssh2_pkt_send(ssh, s->pktout);
9663 logevent("Sent public key signature");
9664 s->type = AUTH_TYPE_PUBLICKEY;
9665 key->alg->freekey(key->data);
9666 sfree(key->comment);
9671 } else if (s->can_gssapi && !s->tried_gssapi) {
9673 /* GSSAPI Authentication */
9678 s->type = AUTH_TYPE_GSSAPI;
9679 s->tried_gssapi = TRUE;
9681 ssh->pkt_actx = SSH2_PKTCTX_GSSAPI;
9684 * Pick the highest GSS library on the preference
9690 for (i = 0; i < ngsslibs; i++) {
9691 int want_id = conf_get_int_int(ssh->conf,
9692 CONF_ssh_gsslist, i);
9693 for (j = 0; j < ssh->gsslibs->nlibraries; j++)
9694 if (ssh->gsslibs->libraries[j].id == want_id) {
9695 s->gsslib = &ssh->gsslibs->libraries[j];
9696 goto got_gsslib; /* double break */
9701 * We always expect to have found something in
9702 * the above loop: we only came here if there
9703 * was at least one viable GSS library, and the
9704 * preference list should always mention
9705 * everything and only change the order.
9710 if (s->gsslib->gsslogmsg)
9711 logevent(s->gsslib->gsslogmsg);
9713 /* Sending USERAUTH_REQUEST with "gssapi-with-mic" method */
9714 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9715 ssh2_pkt_addstring(s->pktout, ssh->username);
9716 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9717 ssh2_pkt_addstring(s->pktout, "gssapi-with-mic");
9718 logevent("Attempting GSSAPI authentication");
9720 /* add mechanism info */
9721 s->gsslib->indicate_mech(s->gsslib, &s->gss_buf);
9723 /* number of GSSAPI mechanisms */
9724 ssh2_pkt_adduint32(s->pktout,1);
9726 /* length of OID + 2 */
9727 ssh2_pkt_adduint32(s->pktout, s->gss_buf.length + 2);
9728 ssh2_pkt_addbyte(s->pktout, SSH2_GSS_OIDTYPE);
9731 ssh2_pkt_addbyte(s->pktout, (unsigned char) s->gss_buf.length);
9733 ssh_pkt_adddata(s->pktout, s->gss_buf.value,
9735 ssh2_pkt_send(ssh, s->pktout);
9736 crWaitUntilV(pktin);
9737 if (pktin->type != SSH2_MSG_USERAUTH_GSSAPI_RESPONSE) {
9738 logevent("GSSAPI authentication request refused");
9742 /* check returned packet ... */
9744 ssh_pkt_getstring(pktin, &data, &len);
9745 s->gss_rcvtok.value = data;
9746 s->gss_rcvtok.length = len;
9747 if (s->gss_rcvtok.length != s->gss_buf.length + 2 ||
9748 ((char *)s->gss_rcvtok.value)[0] != SSH2_GSS_OIDTYPE ||
9749 ((char *)s->gss_rcvtok.value)[1] != s->gss_buf.length ||
9750 memcmp((char *)s->gss_rcvtok.value + 2,
9751 s->gss_buf.value,s->gss_buf.length) ) {
9752 logevent("GSSAPI authentication - wrong response from server");
9756 /* now start running */
9757 s->gss_stat = s->gsslib->import_name(s->gsslib,
9760 if (s->gss_stat != SSH_GSS_OK) {
9761 if (s->gss_stat == SSH_GSS_BAD_HOST_NAME)
9762 logevent("GSSAPI import name failed - Bad service name");
9764 logevent("GSSAPI import name failed");
9768 /* fetch TGT into GSS engine */
9769 s->gss_stat = s->gsslib->acquire_cred(s->gsslib, &s->gss_ctx);
9771 if (s->gss_stat != SSH_GSS_OK) {
9772 logevent("GSSAPI authentication failed to get credentials");
9773 s->gsslib->release_name(s->gsslib, &s->gss_srv_name);
9777 /* initial tokens are empty */
9778 SSH_GSS_CLEAR_BUF(&s->gss_rcvtok);
9779 SSH_GSS_CLEAR_BUF(&s->gss_sndtok);
9781 /* now enter the loop */
9783 s->gss_stat = s->gsslib->init_sec_context
9787 conf_get_int(ssh->conf, CONF_gssapifwd),
9791 if (s->gss_stat!=SSH_GSS_S_COMPLETE &&
9792 s->gss_stat!=SSH_GSS_S_CONTINUE_NEEDED) {
9793 logevent("GSSAPI authentication initialisation failed");
9795 if (s->gsslib->display_status(s->gsslib, s->gss_ctx,
9796 &s->gss_buf) == SSH_GSS_OK) {
9797 logevent(s->gss_buf.value);
9798 sfree(s->gss_buf.value);
9803 logevent("GSSAPI authentication initialised");
9805 /* Client and server now exchange tokens until GSSAPI
9806 * no longer says CONTINUE_NEEDED */
9808 if (s->gss_sndtok.length != 0) {
9809 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
9810 ssh_pkt_addstring_start(s->pktout);
9811 ssh_pkt_addstring_data(s->pktout,s->gss_sndtok.value,s->gss_sndtok.length);
9812 ssh2_pkt_send(ssh, s->pktout);
9813 s->gsslib->free_tok(s->gsslib, &s->gss_sndtok);
9816 if (s->gss_stat == SSH_GSS_S_CONTINUE_NEEDED) {
9817 crWaitUntilV(pktin);
9818 if (pktin->type != SSH2_MSG_USERAUTH_GSSAPI_TOKEN) {
9819 logevent("GSSAPI authentication - bad server response");
9820 s->gss_stat = SSH_GSS_FAILURE;
9823 ssh_pkt_getstring(pktin, &data, &len);
9824 s->gss_rcvtok.value = data;
9825 s->gss_rcvtok.length = len;
9827 } while (s-> gss_stat == SSH_GSS_S_CONTINUE_NEEDED);
9829 if (s->gss_stat != SSH_GSS_OK) {
9830 s->gsslib->release_name(s->gsslib, &s->gss_srv_name);
9831 s->gsslib->release_cred(s->gsslib, &s->gss_ctx);
9834 logevent("GSSAPI authentication loop finished OK");
9836 /* Now send the MIC */
9838 s->pktout = ssh2_pkt_init(0);
9839 micoffset = s->pktout->length;
9840 ssh_pkt_addstring_start(s->pktout);
9841 ssh_pkt_addstring_data(s->pktout, (char *)ssh->v2_session_id, ssh->v2_session_id_len);
9842 ssh_pkt_addbyte(s->pktout, SSH2_MSG_USERAUTH_REQUEST);
9843 ssh_pkt_addstring(s->pktout, ssh->username);
9844 ssh_pkt_addstring(s->pktout, "ssh-connection");
9845 ssh_pkt_addstring(s->pktout, "gssapi-with-mic");
9847 s->gss_buf.value = (char *)s->pktout->data + micoffset;
9848 s->gss_buf.length = s->pktout->length - micoffset;
9850 s->gsslib->get_mic(s->gsslib, s->gss_ctx, &s->gss_buf, &mic);
9851 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_GSSAPI_MIC);
9852 ssh_pkt_addstring_start(s->pktout);
9853 ssh_pkt_addstring_data(s->pktout, mic.value, mic.length);
9854 ssh2_pkt_send(ssh, s->pktout);
9855 s->gsslib->free_mic(s->gsslib, &mic);
9859 s->gsslib->release_name(s->gsslib, &s->gss_srv_name);
9860 s->gsslib->release_cred(s->gsslib, &s->gss_ctx);
9863 } else if (s->can_keyb_inter && !s->kbd_inter_refused) {
9866 * Keyboard-interactive authentication.
9869 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
9871 ssh->pkt_actx = SSH2_PKTCTX_KBDINTER;
9873 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9874 ssh2_pkt_addstring(s->pktout, ssh->username);
9875 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9876 /* service requested */
9877 ssh2_pkt_addstring(s->pktout, "keyboard-interactive");
9879 ssh2_pkt_addstring(s->pktout, ""); /* lang */
9880 ssh2_pkt_addstring(s->pktout, ""); /* submethods */
9881 ssh2_pkt_send(ssh, s->pktout);
9883 logevent("Attempting keyboard-interactive authentication");
9885 crWaitUntilV(pktin);
9886 if (pktin->type != SSH2_MSG_USERAUTH_INFO_REQUEST) {
9887 /* Server is not willing to do keyboard-interactive
9888 * at all (or, bizarrely but legally, accepts the
9889 * user without actually issuing any prompts).
9890 * Give up on it entirely. */
9892 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET;
9893 s->kbd_inter_refused = TRUE; /* don't try it again */
9898 * Loop while the server continues to send INFO_REQUESTs.
9900 while (pktin->type == SSH2_MSG_USERAUTH_INFO_REQUEST) {
9902 char *name, *inst, *lang;
9903 int name_len, inst_len, lang_len;
9907 * We've got a fresh USERAUTH_INFO_REQUEST.
9908 * Get the preamble and start building a prompt.
9910 ssh_pkt_getstring(pktin, &name, &name_len);
9911 ssh_pkt_getstring(pktin, &inst, &inst_len);
9912 ssh_pkt_getstring(pktin, &lang, &lang_len);
9913 s->cur_prompt = new_prompts(ssh->frontend);
9914 s->cur_prompt->to_server = TRUE;
9917 * Get any prompt(s) from the packet.
9919 s->num_prompts = ssh_pkt_getuint32(pktin);
9920 for (i = 0; i < s->num_prompts; i++) {
9924 static char noprompt[] =
9925 "<server failed to send prompt>: ";
9927 ssh_pkt_getstring(pktin, &prompt, &prompt_len);
9928 echo = ssh2_pkt_getbool(pktin);
9931 prompt_len = lenof(noprompt)-1;
9933 add_prompt(s->cur_prompt,
9934 dupprintf("%.*s", prompt_len, prompt),
9939 /* FIXME: better prefix to distinguish from
9941 s->cur_prompt->name =
9942 dupprintf("SSH server: %.*s", name_len, name);
9943 s->cur_prompt->name_reqd = TRUE;
9945 s->cur_prompt->name =
9946 dupstr("SSH server authentication");
9947 s->cur_prompt->name_reqd = FALSE;
9949 /* We add a prefix to try to make it clear that a prompt
9950 * has come from the server.
9951 * FIXME: ugly to print "Using..." in prompt _every_
9952 * time round. Can this be done more subtly? */
9953 /* Special case: for reasons best known to themselves,
9954 * some servers send k-i requests with no prompts and
9955 * nothing to display. Keep quiet in this case. */
9956 if (s->num_prompts || name_len || inst_len) {
9957 s->cur_prompt->instruction =
9958 dupprintf("Using keyboard-interactive authentication.%s%.*s",
9959 inst_len ? "\n" : "", inst_len, inst);
9960 s->cur_prompt->instr_reqd = TRUE;
9962 s->cur_prompt->instr_reqd = FALSE;
9966 * Display any instructions, and get the user's
9970 int ret; /* not live over crReturn */
9971 ret = get_userpass_input(s->cur_prompt, NULL, 0);
9974 crWaitUntilV(!pktin);
9975 ret = get_userpass_input(s->cur_prompt, in, inlen);
9980 * Failed to get responses. Terminate.
9982 free_prompts(s->cur_prompt);
9983 ssh_disconnect(ssh, NULL, "Unable to authenticate",
9984 SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER,
9991 * Send the response(s) to the server.
9993 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_INFO_RESPONSE);
9994 ssh2_pkt_adduint32(s->pktout, s->num_prompts);
9995 for (i=0; i < s->num_prompts; i++) {
9996 ssh2_pkt_addstring(s->pktout,
9997 s->cur_prompt->prompts[i]->result);
9999 ssh2_pkt_send_with_padding(ssh, s->pktout, 256);
10002 * Free the prompts structure from this iteration.
10003 * If there's another, a new one will be allocated
10004 * when we return to the top of this while loop.
10006 free_prompts(s->cur_prompt);
10009 * Get the next packet in case it's another
10012 crWaitUntilV(pktin);
10017 * We should have SUCCESS or FAILURE now.
10021 } else if (s->can_passwd) {
10024 * Plain old password authentication.
10026 int ret; /* not live over crReturn */
10027 int changereq_first_time; /* not live over crReturn */
10029 ssh->pkt_actx = SSH2_PKTCTX_PASSWORD;
10031 s->cur_prompt = new_prompts(ssh->frontend);
10032 s->cur_prompt->to_server = TRUE;
10033 s->cur_prompt->name = dupstr("SSH password");
10034 add_prompt(s->cur_prompt, dupprintf("%s@%s's password: ",
10039 ret = get_userpass_input(s->cur_prompt, NULL, 0);
10042 crWaitUntilV(!pktin);
10043 ret = get_userpass_input(s->cur_prompt, in, inlen);
10048 * Failed to get responses. Terminate.
10050 free_prompts(s->cur_prompt);
10051 ssh_disconnect(ssh, NULL, "Unable to authenticate",
10052 SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER,
10057 * Squirrel away the password. (We may need it later if
10058 * asked to change it.)
10060 s->password = dupstr(s->cur_prompt->prompts[0]->result);
10061 free_prompts(s->cur_prompt);
10064 * Send the password packet.
10066 * We pad out the password packet to 256 bytes to make
10067 * it harder for an attacker to find the length of the
10070 * Anyone using a password longer than 256 bytes
10071 * probably doesn't have much to worry about from
10072 * people who find out how long their password is!
10074 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
10075 ssh2_pkt_addstring(s->pktout, ssh->username);
10076 ssh2_pkt_addstring(s->pktout, "ssh-connection");
10077 /* service requested */
10078 ssh2_pkt_addstring(s->pktout, "password");
10079 ssh2_pkt_addbool(s->pktout, FALSE);
10080 ssh2_pkt_addstring(s->pktout, s->password);
10081 ssh2_pkt_send_with_padding(ssh, s->pktout, 256);
10082 logevent("Sent password");
10083 s->type = AUTH_TYPE_PASSWORD;
10086 * Wait for next packet, in case it's a password change
10089 crWaitUntilV(pktin);
10090 changereq_first_time = TRUE;
10092 while (pktin->type == SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ) {
10095 * We're being asked for a new password
10096 * (perhaps not for the first time).
10097 * Loop until the server accepts it.
10100 int got_new = FALSE; /* not live over crReturn */
10101 char *prompt; /* not live over crReturn */
10102 int prompt_len; /* not live over crReturn */
10106 if (changereq_first_time)
10107 msg = "Server requested password change";
10109 msg = "Server rejected new password";
10111 c_write_str(ssh, msg);
10112 c_write_str(ssh, "\r\n");
10115 ssh_pkt_getstring(pktin, &prompt, &prompt_len);
10117 s->cur_prompt = new_prompts(ssh->frontend);
10118 s->cur_prompt->to_server = TRUE;
10119 s->cur_prompt->name = dupstr("New SSH password");
10120 s->cur_prompt->instruction =
10121 dupprintf("%.*s", prompt_len, prompt);
10122 s->cur_prompt->instr_reqd = TRUE;
10124 * There's no explicit requirement in the protocol
10125 * for the "old" passwords in the original and
10126 * password-change messages to be the same, and
10127 * apparently some Cisco kit supports password change
10128 * by the user entering a blank password originally
10129 * and the real password subsequently, so,
10130 * reluctantly, we prompt for the old password again.
10132 * (On the other hand, some servers don't even bother
10133 * to check this field.)
10135 add_prompt(s->cur_prompt,
10136 dupstr("Current password (blank for previously entered password): "),
10138 add_prompt(s->cur_prompt, dupstr("Enter new password: "),
10140 add_prompt(s->cur_prompt, dupstr("Confirm new password: "),
10144 * Loop until the user manages to enter the same
10149 ret = get_userpass_input(s->cur_prompt, NULL, 0);
10152 crWaitUntilV(!pktin);
10153 ret = get_userpass_input(s->cur_prompt, in, inlen);
10158 * Failed to get responses. Terminate.
10160 /* burn the evidence */
10161 free_prompts(s->cur_prompt);
10162 smemclr(s->password, strlen(s->password));
10163 sfree(s->password);
10164 ssh_disconnect(ssh, NULL, "Unable to authenticate",
10165 SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER,
10171 * If the user specified a new original password
10172 * (IYSWIM), overwrite any previously specified
10174 * (A side effect is that the user doesn't have to
10175 * re-enter it if they louse up the new password.)
10177 if (s->cur_prompt->prompts[0]->result[0]) {
10178 smemclr(s->password, strlen(s->password));
10179 /* burn the evidence */
10180 sfree(s->password);
10182 dupstr(s->cur_prompt->prompts[0]->result);
10186 * Check the two new passwords match.
10188 got_new = (strcmp(s->cur_prompt->prompts[1]->result,
10189 s->cur_prompt->prompts[2]->result)
10192 /* They don't. Silly user. */
10193 c_write_str(ssh, "Passwords do not match\r\n");
10198 * Send the new password (along with the old one).
10199 * (see above for padding rationale)
10201 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
10202 ssh2_pkt_addstring(s->pktout, ssh->username);
10203 ssh2_pkt_addstring(s->pktout, "ssh-connection");
10204 /* service requested */
10205 ssh2_pkt_addstring(s->pktout, "password");
10206 ssh2_pkt_addbool(s->pktout, TRUE);
10207 ssh2_pkt_addstring(s->pktout, s->password);
10208 ssh2_pkt_addstring(s->pktout,
10209 s->cur_prompt->prompts[1]->result);
10210 free_prompts(s->cur_prompt);
10211 ssh2_pkt_send_with_padding(ssh, s->pktout, 256);
10212 logevent("Sent new password");
10215 * Now see what the server has to say about it.
10216 * (If it's CHANGEREQ again, it's not happy with the
10219 crWaitUntilV(pktin);
10220 changereq_first_time = FALSE;
10225 * We need to reexamine the current pktin at the top
10226 * of the loop. Either:
10227 * - we weren't asked to change password at all, in
10228 * which case it's a SUCCESS or FAILURE with the
10230 * - we sent a new password, and the server was
10231 * either OK with it (SUCCESS or FAILURE w/partial
10232 * success) or unhappy with the _old_ password
10233 * (FAILURE w/o partial success)
10234 * In any of these cases, we go back to the top of
10235 * the loop and start again.
10240 * We don't need the old password any more, in any
10241 * case. Burn the evidence.
10243 smemclr(s->password, strlen(s->password));
10244 sfree(s->password);
10247 char *str = dupprintf("No supported authentication methods available"
10248 " (server sent: %.*s)",
10251 ssh_disconnect(ssh, str,
10252 "No supported authentication methods available",
10253 SSH2_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE,
10263 ssh->packet_dispatch[SSH2_MSG_USERAUTH_BANNER] = NULL;
10265 /* Clear up various bits and pieces from authentication. */
10266 if (s->publickey_blob) {
10267 sfree(s->publickey_blob);
10268 sfree(s->publickey_comment);
10270 if (s->agent_response)
10271 sfree(s->agent_response);
10273 if (s->userauth_success && !ssh->bare_connection) {
10275 * We've just received USERAUTH_SUCCESS, and we haven't sent any
10276 * packets since. Signal the transport layer to consider enacting
10277 * delayed compression.
10279 * (Relying on we_are_in is not sufficient, as
10280 * draft-miller-secsh-compression-delayed is quite clear that it
10281 * triggers on USERAUTH_SUCCESS specifically, and we_are_in can
10282 * become set for other reasons.)
10284 do_ssh2_transport(ssh, "enabling delayed compression", -2, NULL);
10287 ssh->channels = newtree234(ssh_channelcmp);
10290 * Set up handlers for some connection protocol messages, so we
10291 * don't have to handle them repeatedly in this coroutine.
10293 ssh->packet_dispatch[SSH2_MSG_CHANNEL_WINDOW_ADJUST] =
10294 ssh2_msg_channel_window_adjust;
10295 ssh->packet_dispatch[SSH2_MSG_GLOBAL_REQUEST] =
10296 ssh2_msg_global_request;
10299 * Create the main session channel.
10301 if (conf_get_int(ssh->conf, CONF_ssh_no_shell)) {
10302 ssh->mainchan = NULL;
10304 ssh->mainchan = snew(struct ssh_channel);
10305 ssh->mainchan->ssh = ssh;
10306 ssh2_channel_init(ssh->mainchan);
10308 if (*conf_get_str(ssh->conf, CONF_ssh_nc_host)) {
10310 * Just start a direct-tcpip channel and use it as the main
10313 ssh_send_port_open(ssh->mainchan,
10314 conf_get_str(ssh->conf, CONF_ssh_nc_host),
10315 conf_get_int(ssh->conf, CONF_ssh_nc_port),
10317 ssh->ncmode = TRUE;
10319 s->pktout = ssh2_chanopen_init(ssh->mainchan, "session");
10320 logevent("Opening session as main channel");
10321 ssh2_pkt_send(ssh, s->pktout);
10322 ssh->ncmode = FALSE;
10324 crWaitUntilV(pktin);
10325 if (pktin->type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
10326 bombout(("Server refused to open channel"));
10328 /* FIXME: error data comes back in FAILURE packet */
10330 if (ssh_pkt_getuint32(pktin) != ssh->mainchan->localid) {
10331 bombout(("Server's channel confirmation cited wrong channel"));
10334 ssh->mainchan->remoteid = ssh_pkt_getuint32(pktin);
10335 ssh->mainchan->halfopen = FALSE;
10336 ssh->mainchan->type = CHAN_MAINSESSION;
10337 ssh->mainchan->v.v2.remwindow = ssh_pkt_getuint32(pktin);
10338 ssh->mainchan->v.v2.remmaxpkt = ssh_pkt_getuint32(pktin);
10339 add234(ssh->channels, ssh->mainchan);
10340 update_specials_menu(ssh->frontend);
10341 logevent("Opened main channel");
10345 * Now we have a channel, make dispatch table entries for
10346 * general channel-based messages.
10348 ssh->packet_dispatch[SSH2_MSG_CHANNEL_DATA] =
10349 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EXTENDED_DATA] =
10350 ssh2_msg_channel_data;
10351 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EOF] = ssh2_msg_channel_eof;
10352 ssh->packet_dispatch[SSH2_MSG_CHANNEL_CLOSE] = ssh2_msg_channel_close;
10353 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_CONFIRMATION] =
10354 ssh2_msg_channel_open_confirmation;
10355 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_FAILURE] =
10356 ssh2_msg_channel_open_failure;
10357 ssh->packet_dispatch[SSH2_MSG_CHANNEL_REQUEST] =
10358 ssh2_msg_channel_request;
10359 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN] =
10360 ssh2_msg_channel_open;
10361 ssh->packet_dispatch[SSH2_MSG_CHANNEL_SUCCESS] = ssh2_msg_channel_response;
10362 ssh->packet_dispatch[SSH2_MSG_CHANNEL_FAILURE] = ssh2_msg_channel_response;
10365 * Now the connection protocol is properly up and running, with
10366 * all those dispatch table entries, so it's safe to let
10367 * downstreams start trying to open extra channels through us.
10369 if (ssh->connshare)
10370 share_activate(ssh->connshare, ssh->v_s);
10372 if (ssh->mainchan && ssh_is_simple(ssh)) {
10374 * This message indicates to the server that we promise
10375 * not to try to run any other channel in parallel with
10376 * this one, so it's safe for it to advertise a very large
10377 * window and leave the flow control to TCP.
10379 s->pktout = ssh2_chanreq_init(ssh->mainchan,
10380 "simple@putty.projects.tartarus.org",
10382 ssh2_pkt_send(ssh, s->pktout);
10386 * Enable port forwardings.
10388 ssh_setup_portfwd(ssh, ssh->conf);
10390 if (ssh->mainchan && !ssh->ncmode) {
10392 * Send the CHANNEL_REQUESTS for the main session channel.
10393 * Each one is handled by its own little asynchronous
10397 /* Potentially enable X11 forwarding. */
10398 if (conf_get_int(ssh->conf, CONF_x11_forward)) {
10400 x11_setup_display(conf_get_str(ssh->conf, CONF_x11_display),
10402 if (!ssh->x11disp) {
10403 /* FIXME: return an error message from x11_setup_display */
10404 logevent("X11 forwarding not enabled: unable to"
10405 " initialise X display");
10407 ssh->x11auth = x11_invent_fake_auth
10408 (ssh->x11authtree, conf_get_int(ssh->conf, CONF_x11_auth));
10409 ssh->x11auth->disp = ssh->x11disp;
10411 ssh2_setup_x11(ssh->mainchan, NULL, NULL);
10415 /* Potentially enable agent forwarding. */
10416 if (ssh_agent_forwarding_permitted(ssh))
10417 ssh2_setup_agent(ssh->mainchan, NULL, NULL);
10419 /* Now allocate a pty for the session. */
10420 if (!conf_get_int(ssh->conf, CONF_nopty))
10421 ssh2_setup_pty(ssh->mainchan, NULL, NULL);
10423 /* Send environment variables. */
10424 ssh2_setup_env(ssh->mainchan, NULL, NULL);
10427 * Start a shell or a remote command. We may have to attempt
10428 * this twice if the config data has provided a second choice
10435 if (ssh->fallback_cmd) {
10436 subsys = conf_get_int(ssh->conf, CONF_ssh_subsys2);
10437 cmd = conf_get_str(ssh->conf, CONF_remote_cmd2);
10439 subsys = conf_get_int(ssh->conf, CONF_ssh_subsys);
10440 cmd = conf_get_str(ssh->conf, CONF_remote_cmd);
10444 s->pktout = ssh2_chanreq_init(ssh->mainchan, "subsystem",
10445 ssh2_response_authconn, NULL);
10446 ssh2_pkt_addstring(s->pktout, cmd);
10448 s->pktout = ssh2_chanreq_init(ssh->mainchan, "exec",
10449 ssh2_response_authconn, NULL);
10450 ssh2_pkt_addstring(s->pktout, cmd);
10452 s->pktout = ssh2_chanreq_init(ssh->mainchan, "shell",
10453 ssh2_response_authconn, NULL);
10455 ssh2_pkt_send(ssh, s->pktout);
10457 crWaitUntilV(pktin);
10459 if (pktin->type != SSH2_MSG_CHANNEL_SUCCESS) {
10460 if (pktin->type != SSH2_MSG_CHANNEL_FAILURE) {
10461 bombout(("Unexpected response to shell/command request:"
10462 " packet type %d", pktin->type));
10466 * We failed to start the command. If this is the
10467 * fallback command, we really are finished; if it's
10468 * not, and if the fallback command exists, try falling
10469 * back to it before complaining.
10471 if (!ssh->fallback_cmd &&
10472 *conf_get_str(ssh->conf, CONF_remote_cmd2)) {
10473 logevent("Primary command failed; attempting fallback");
10474 ssh->fallback_cmd = TRUE;
10477 bombout(("Server refused to start a shell/command"));
10480 logevent("Started a shell/command");
10485 ssh->editing = ssh->echoing = TRUE;
10488 ssh->state = SSH_STATE_SESSION;
10489 if (ssh->size_needed)
10490 ssh_size(ssh, ssh->term_width, ssh->term_height);
10491 if (ssh->eof_needed)
10492 ssh_special(ssh, TS_EOF);
10498 ldisc_echoedit_update(ssh->ldisc); /* cause ldisc to notice changes */
10503 s->try_send = FALSE;
10507 * _All_ the connection-layer packets we expect to
10508 * receive are now handled by the dispatch table.
10509 * Anything that reaches here must be bogus.
10512 bombout(("Strange packet received: type %d", pktin->type));
10514 } else if (ssh->mainchan) {
10516 * We have spare data. Add it to the channel buffer.
10518 ssh2_add_channel_data(ssh->mainchan, (char *)in, inlen);
10519 s->try_send = TRUE;
10523 struct ssh_channel *c;
10525 * Try to send data on all channels if we can.
10527 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++)
10528 ssh2_try_send_and_unthrottle(ssh, c);
10536 * Handlers for SSH-2 messages that might arrive at any moment.
10538 static void ssh2_msg_disconnect(Ssh ssh, struct Packet *pktin)
10540 /* log reason code in disconnect message */
10542 int reason, msglen;
10544 reason = ssh_pkt_getuint32(pktin);
10545 ssh_pkt_getstring(pktin, &msg, &msglen);
10547 if (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) {
10548 buf = dupprintf("Received disconnect message (%s)",
10549 ssh2_disconnect_reasons[reason]);
10551 buf = dupprintf("Received disconnect message (unknown"
10552 " type %d)", reason);
10556 buf = dupprintf("Disconnection message text: %.*s",
10559 bombout(("Server sent disconnect message\ntype %d (%s):\n\"%.*s\"",
10561 (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) ?
10562 ssh2_disconnect_reasons[reason] : "unknown",
10567 static void ssh2_msg_debug(Ssh ssh, struct Packet *pktin)
10569 /* log the debug message */
10573 /* XXX maybe we should actually take notice of the return value */
10574 ssh2_pkt_getbool(pktin);
10575 ssh_pkt_getstring(pktin, &msg, &msglen);
10577 logeventf(ssh, "Remote debug message: %.*s", msglen, msg);
10580 static void ssh2_msg_transport(Ssh ssh, struct Packet *pktin)
10582 do_ssh2_transport(ssh, NULL, 0, pktin);
10586 * Called if we receive a packet that isn't allowed by the protocol.
10587 * This only applies to packets whose meaning PuTTY understands.
10588 * Entirely unknown packets are handled below.
10590 static void ssh2_msg_unexpected(Ssh ssh, struct Packet *pktin)
10592 char *buf = dupprintf("Server protocol violation: unexpected %s packet",
10593 ssh2_pkt_type(ssh->pkt_kctx, ssh->pkt_actx,
10595 ssh_disconnect(ssh, NULL, buf, SSH2_DISCONNECT_PROTOCOL_ERROR, FALSE);
10599 static void ssh2_msg_something_unimplemented(Ssh ssh, struct Packet *pktin)
10601 struct Packet *pktout;
10602 pktout = ssh2_pkt_init(SSH2_MSG_UNIMPLEMENTED);
10603 ssh2_pkt_adduint32(pktout, pktin->sequence);
10605 * UNIMPLEMENTED messages MUST appear in the same order as the
10606 * messages they respond to. Hence, never queue them.
10608 ssh2_pkt_send_noqueue(ssh, pktout);
10612 * Handle the top-level SSH-2 protocol.
10614 static void ssh2_protocol_setup(Ssh ssh)
10619 * Most messages cause SSH2_MSG_UNIMPLEMENTED.
10621 for (i = 0; i < 256; i++)
10622 ssh->packet_dispatch[i] = ssh2_msg_something_unimplemented;
10625 * Initially, we only accept transport messages (and a few generic
10626 * ones). do_ssh2_authconn will add more when it starts.
10627 * Messages that are understood but not currently acceptable go to
10628 * ssh2_msg_unexpected.
10630 ssh->packet_dispatch[SSH2_MSG_UNIMPLEMENTED] = ssh2_msg_unexpected;
10631 ssh->packet_dispatch[SSH2_MSG_SERVICE_REQUEST] = ssh2_msg_unexpected;
10632 ssh->packet_dispatch[SSH2_MSG_SERVICE_ACCEPT] = ssh2_msg_unexpected;
10633 ssh->packet_dispatch[SSH2_MSG_KEXINIT] = ssh2_msg_transport;
10634 ssh->packet_dispatch[SSH2_MSG_NEWKEYS] = ssh2_msg_transport;
10635 ssh->packet_dispatch[SSH2_MSG_KEXDH_INIT] = ssh2_msg_transport;
10636 ssh->packet_dispatch[SSH2_MSG_KEXDH_REPLY] = ssh2_msg_transport;
10637 /* ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_REQUEST] = ssh2_msg_transport; duplicate case value */
10638 /* ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_GROUP] = ssh2_msg_transport; duplicate case value */
10639 ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_INIT] = ssh2_msg_transport;
10640 ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_REPLY] = ssh2_msg_transport;
10641 ssh->packet_dispatch[SSH2_MSG_USERAUTH_REQUEST] = ssh2_msg_unexpected;
10642 ssh->packet_dispatch[SSH2_MSG_USERAUTH_FAILURE] = ssh2_msg_unexpected;
10643 ssh->packet_dispatch[SSH2_MSG_USERAUTH_SUCCESS] = ssh2_msg_unexpected;
10644 ssh->packet_dispatch[SSH2_MSG_USERAUTH_BANNER] = ssh2_msg_unexpected;
10645 ssh->packet_dispatch[SSH2_MSG_USERAUTH_PK_OK] = ssh2_msg_unexpected;
10646 /* ssh->packet_dispatch[SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ] = ssh2_msg_unexpected; duplicate case value */
10647 /* ssh->packet_dispatch[SSH2_MSG_USERAUTH_INFO_REQUEST] = ssh2_msg_unexpected; duplicate case value */
10648 ssh->packet_dispatch[SSH2_MSG_USERAUTH_INFO_RESPONSE] = ssh2_msg_unexpected;
10649 ssh->packet_dispatch[SSH2_MSG_GLOBAL_REQUEST] = ssh2_msg_unexpected;
10650 ssh->packet_dispatch[SSH2_MSG_REQUEST_SUCCESS] = ssh2_msg_unexpected;
10651 ssh->packet_dispatch[SSH2_MSG_REQUEST_FAILURE] = ssh2_msg_unexpected;
10652 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN] = ssh2_msg_unexpected;
10653 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_CONFIRMATION] = ssh2_msg_unexpected;
10654 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_FAILURE] = ssh2_msg_unexpected;
10655 ssh->packet_dispatch[SSH2_MSG_CHANNEL_WINDOW_ADJUST] = ssh2_msg_unexpected;
10656 ssh->packet_dispatch[SSH2_MSG_CHANNEL_DATA] = ssh2_msg_unexpected;
10657 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EXTENDED_DATA] = ssh2_msg_unexpected;
10658 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EOF] = ssh2_msg_unexpected;
10659 ssh->packet_dispatch[SSH2_MSG_CHANNEL_CLOSE] = ssh2_msg_unexpected;
10660 ssh->packet_dispatch[SSH2_MSG_CHANNEL_REQUEST] = ssh2_msg_unexpected;
10661 ssh->packet_dispatch[SSH2_MSG_CHANNEL_SUCCESS] = ssh2_msg_unexpected;
10662 ssh->packet_dispatch[SSH2_MSG_CHANNEL_FAILURE] = ssh2_msg_unexpected;
10665 * These messages have a special handler from the start.
10667 ssh->packet_dispatch[SSH2_MSG_DISCONNECT] = ssh2_msg_disconnect;
10668 ssh->packet_dispatch[SSH2_MSG_IGNORE] = ssh_msg_ignore; /* shared with SSH-1 */
10669 ssh->packet_dispatch[SSH2_MSG_DEBUG] = ssh2_msg_debug;
10672 static void ssh2_bare_connection_protocol_setup(Ssh ssh)
10677 * Most messages cause SSH2_MSG_UNIMPLEMENTED.
10679 for (i = 0; i < 256; i++)
10680 ssh->packet_dispatch[i] = ssh2_msg_something_unimplemented;
10683 * Initially, we set all ssh-connection messages to 'unexpected';
10684 * do_ssh2_authconn will fill things in properly. We also handle a
10685 * couple of messages from the transport protocol which aren't
10686 * related to key exchange (UNIMPLEMENTED, IGNORE, DEBUG,
10689 ssh->packet_dispatch[SSH2_MSG_GLOBAL_REQUEST] = ssh2_msg_unexpected;
10690 ssh->packet_dispatch[SSH2_MSG_REQUEST_SUCCESS] = ssh2_msg_unexpected;
10691 ssh->packet_dispatch[SSH2_MSG_REQUEST_FAILURE] = ssh2_msg_unexpected;
10692 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN] = ssh2_msg_unexpected;
10693 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_CONFIRMATION] = ssh2_msg_unexpected;
10694 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_FAILURE] = ssh2_msg_unexpected;
10695 ssh->packet_dispatch[SSH2_MSG_CHANNEL_WINDOW_ADJUST] = ssh2_msg_unexpected;
10696 ssh->packet_dispatch[SSH2_MSG_CHANNEL_DATA] = ssh2_msg_unexpected;
10697 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EXTENDED_DATA] = ssh2_msg_unexpected;
10698 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EOF] = ssh2_msg_unexpected;
10699 ssh->packet_dispatch[SSH2_MSG_CHANNEL_CLOSE] = ssh2_msg_unexpected;
10700 ssh->packet_dispatch[SSH2_MSG_CHANNEL_REQUEST] = ssh2_msg_unexpected;
10701 ssh->packet_dispatch[SSH2_MSG_CHANNEL_SUCCESS] = ssh2_msg_unexpected;
10702 ssh->packet_dispatch[SSH2_MSG_CHANNEL_FAILURE] = ssh2_msg_unexpected;
10704 ssh->packet_dispatch[SSH2_MSG_UNIMPLEMENTED] = ssh2_msg_unexpected;
10707 * These messages have a special handler from the start.
10709 ssh->packet_dispatch[SSH2_MSG_DISCONNECT] = ssh2_msg_disconnect;
10710 ssh->packet_dispatch[SSH2_MSG_IGNORE] = ssh_msg_ignore;
10711 ssh->packet_dispatch[SSH2_MSG_DEBUG] = ssh2_msg_debug;
10714 static void ssh2_timer(void *ctx, unsigned long now)
10716 Ssh ssh = (Ssh)ctx;
10718 if (ssh->state == SSH_STATE_CLOSED)
10721 if (!ssh->kex_in_progress && !ssh->bare_connection &&
10722 conf_get_int(ssh->conf, CONF_ssh_rekey_time) != 0 &&
10723 now == ssh->next_rekey) {
10724 do_ssh2_transport(ssh, "timeout", -1, NULL);
10728 static void ssh2_protocol(Ssh ssh, void *vin, int inlen,
10729 struct Packet *pktin)
10731 unsigned char *in = (unsigned char *)vin;
10732 if (ssh->state == SSH_STATE_CLOSED)
10736 ssh->incoming_data_size += pktin->encrypted_len;
10737 if (!ssh->kex_in_progress &&
10738 ssh->max_data_size != 0 &&
10739 ssh->incoming_data_size > ssh->max_data_size)
10740 do_ssh2_transport(ssh, "too much data received", -1, NULL);
10744 ssh->packet_dispatch[pktin->type](ssh, pktin);
10745 else if (!ssh->protocol_initial_phase_done)
10746 do_ssh2_transport(ssh, in, inlen, pktin);
10748 do_ssh2_authconn(ssh, in, inlen, pktin);
10751 static void ssh2_bare_connection_protocol(Ssh ssh, void *vin, int inlen,
10752 struct Packet *pktin)
10754 unsigned char *in = (unsigned char *)vin;
10755 if (ssh->state == SSH_STATE_CLOSED)
10759 ssh->packet_dispatch[pktin->type](ssh, pktin);
10761 do_ssh2_authconn(ssh, in, inlen, pktin);
10764 static void ssh_cache_conf_values(Ssh ssh)
10766 ssh->logomitdata = conf_get_int(ssh->conf, CONF_logomitdata);
10770 * Called to set up the connection.
10772 * Returns an error message, or NULL on success.
10774 static const char *ssh_init(void *frontend_handle, void **backend_handle,
10775 Conf *conf, char *host, int port, char **realhost,
10776 int nodelay, int keepalive)
10781 ssh = snew(struct ssh_tag);
10782 ssh->conf = conf_copy(conf);
10783 ssh_cache_conf_values(ssh);
10784 ssh->version = 0; /* when not ready yet */
10786 ssh->cipher = NULL;
10787 ssh->v1_cipher_ctx = NULL;
10788 ssh->crcda_ctx = NULL;
10789 ssh->cscipher = NULL;
10790 ssh->cs_cipher_ctx = NULL;
10791 ssh->sccipher = NULL;
10792 ssh->sc_cipher_ctx = NULL;
10794 ssh->cs_mac_ctx = NULL;
10796 ssh->sc_mac_ctx = NULL;
10797 ssh->cscomp = NULL;
10798 ssh->cs_comp_ctx = NULL;
10799 ssh->sccomp = NULL;
10800 ssh->sc_comp_ctx = NULL;
10802 ssh->kex_ctx = NULL;
10803 ssh->hostkey = NULL;
10804 ssh->hostkey_str = NULL;
10805 ssh->exitcode = -1;
10806 ssh->close_expected = FALSE;
10807 ssh->clean_exit = FALSE;
10808 ssh->state = SSH_STATE_PREPACKET;
10809 ssh->size_needed = FALSE;
10810 ssh->eof_needed = FALSE;
10812 ssh->logctx = NULL;
10813 ssh->deferred_send_data = NULL;
10814 ssh->deferred_len = 0;
10815 ssh->deferred_size = 0;
10816 ssh->fallback_cmd = 0;
10817 ssh->pkt_kctx = SSH2_PKTCTX_NOKEX;
10818 ssh->pkt_actx = SSH2_PKTCTX_NOAUTH;
10819 ssh->x11disp = NULL;
10820 ssh->x11auth = NULL;
10821 ssh->x11authtree = newtree234(x11_authcmp);
10822 ssh->v1_compressing = FALSE;
10823 ssh->v2_outgoing_sequence = 0;
10824 ssh->ssh1_rdpkt_crstate = 0;
10825 ssh->ssh2_rdpkt_crstate = 0;
10826 ssh->ssh2_bare_rdpkt_crstate = 0;
10827 ssh->ssh_gotdata_crstate = 0;
10828 ssh->do_ssh1_connection_crstate = 0;
10829 ssh->do_ssh_init_state = NULL;
10830 ssh->do_ssh_connection_init_state = NULL;
10831 ssh->do_ssh1_login_state = NULL;
10832 ssh->do_ssh2_transport_state = NULL;
10833 ssh->do_ssh2_authconn_state = NULL;
10836 ssh->mainchan = NULL;
10837 ssh->throttled_all = 0;
10838 ssh->v1_stdout_throttling = 0;
10840 ssh->queuelen = ssh->queuesize = 0;
10841 ssh->queueing = FALSE;
10842 ssh->qhead = ssh->qtail = NULL;
10843 ssh->deferred_rekey_reason = NULL;
10844 bufchain_init(&ssh->queued_incoming_data);
10845 ssh->frozen = FALSE;
10846 ssh->username = NULL;
10847 ssh->sent_console_eof = FALSE;
10848 ssh->got_pty = FALSE;
10849 ssh->bare_connection = FALSE;
10850 ssh->X11_fwd_enabled = FALSE;
10851 ssh->connshare = NULL;
10852 ssh->attempting_connshare = FALSE;
10854 *backend_handle = ssh;
10857 if (crypto_startup() == 0)
10858 return "Microsoft high encryption pack not installed!";
10861 ssh->frontend = frontend_handle;
10862 ssh->term_width = conf_get_int(ssh->conf, CONF_width);
10863 ssh->term_height = conf_get_int(ssh->conf, CONF_height);
10865 ssh->channels = NULL;
10866 ssh->rportfwds = NULL;
10867 ssh->portfwds = NULL;
10872 ssh->conn_throttle_count = 0;
10873 ssh->overall_bufsize = 0;
10874 ssh->fallback_cmd = 0;
10876 ssh->protocol = NULL;
10878 ssh->protocol_initial_phase_done = FALSE;
10880 ssh->pinger = NULL;
10882 ssh->incoming_data_size = ssh->outgoing_data_size =
10883 ssh->deferred_data_size = 0L;
10884 ssh->max_data_size = parse_blocksize(conf_get_str(ssh->conf,
10885 CONF_ssh_rekey_data));
10886 ssh->kex_in_progress = FALSE;
10889 ssh->gsslibs = NULL;
10892 random_ref(); /* do this now - may be needed by sharing setup code */
10894 p = connect_to_host(ssh, host, port, realhost, nodelay, keepalive);
10903 static void ssh_free(void *handle)
10905 Ssh ssh = (Ssh) handle;
10906 struct ssh_channel *c;
10907 struct ssh_rportfwd *pf;
10908 struct X11FakeAuth *auth;
10910 if (ssh->v1_cipher_ctx)
10911 ssh->cipher->free_context(ssh->v1_cipher_ctx);
10912 if (ssh->cs_cipher_ctx)
10913 ssh->cscipher->free_context(ssh->cs_cipher_ctx);
10914 if (ssh->sc_cipher_ctx)
10915 ssh->sccipher->free_context(ssh->sc_cipher_ctx);
10916 if (ssh->cs_mac_ctx)
10917 ssh->csmac->free_context(ssh->cs_mac_ctx);
10918 if (ssh->sc_mac_ctx)
10919 ssh->scmac->free_context(ssh->sc_mac_ctx);
10920 if (ssh->cs_comp_ctx) {
10922 ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
10924 zlib_compress_cleanup(ssh->cs_comp_ctx);
10926 if (ssh->sc_comp_ctx) {
10928 ssh->sccomp->decompress_cleanup(ssh->sc_comp_ctx);
10930 zlib_decompress_cleanup(ssh->sc_comp_ctx);
10933 dh_cleanup(ssh->kex_ctx);
10934 sfree(ssh->savedhost);
10936 while (ssh->queuelen-- > 0)
10937 ssh_free_packet(ssh->queue[ssh->queuelen]);
10940 while (ssh->qhead) {
10941 struct queued_handler *qh = ssh->qhead;
10942 ssh->qhead = qh->next;
10945 ssh->qhead = ssh->qtail = NULL;
10947 if (ssh->channels) {
10948 while ((c = delpos234(ssh->channels, 0)) != NULL) {
10951 if (c->u.x11.xconn != NULL)
10952 x11_close(c->u.x11.xconn);
10954 case CHAN_SOCKDATA:
10955 case CHAN_SOCKDATA_DORMANT:
10956 if (c->u.pfd.pf != NULL)
10957 pfd_close(c->u.pfd.pf);
10960 if (ssh->version == 2) {
10961 struct outstanding_channel_request *ocr, *nocr;
10962 ocr = c->v.v2.chanreq_head;
10964 ocr->handler(c, NULL, ocr->ctx);
10969 bufchain_clear(&c->v.v2.outbuffer);
10973 freetree234(ssh->channels);
10974 ssh->channels = NULL;
10977 if (ssh->connshare)
10978 sharestate_free(ssh->connshare);
10980 if (ssh->rportfwds) {
10981 while ((pf = delpos234(ssh->rportfwds, 0)) != NULL)
10983 freetree234(ssh->rportfwds);
10984 ssh->rportfwds = NULL;
10986 sfree(ssh->deferred_send_data);
10988 x11_free_display(ssh->x11disp);
10989 while ((auth = delpos234(ssh->x11authtree, 0)) != NULL)
10990 x11_free_fake_auth(auth);
10991 freetree234(ssh->x11authtree);
10992 sfree(ssh->do_ssh_init_state);
10993 sfree(ssh->do_ssh1_login_state);
10994 sfree(ssh->do_ssh2_transport_state);
10995 sfree(ssh->do_ssh2_authconn_state);
10998 sfree(ssh->fullhostname);
10999 sfree(ssh->hostkey_str);
11000 if (ssh->crcda_ctx) {
11001 crcda_free_context(ssh->crcda_ctx);
11002 ssh->crcda_ctx = NULL;
11005 ssh_do_close(ssh, TRUE);
11006 expire_timer_context(ssh);
11008 pinger_free(ssh->pinger);
11009 bufchain_clear(&ssh->queued_incoming_data);
11010 sfree(ssh->username);
11011 conf_free(ssh->conf);
11014 ssh_gss_cleanup(ssh->gsslibs);
11022 * Reconfigure the SSH backend.
11024 static void ssh_reconfig(void *handle, Conf *conf)
11026 Ssh ssh = (Ssh) handle;
11027 char *rekeying = NULL, rekey_mandatory = FALSE;
11028 unsigned long old_max_data_size;
11031 pinger_reconfig(ssh->pinger, ssh->conf, conf);
11033 ssh_setup_portfwd(ssh, conf);
11035 rekey_time = conf_get_int(conf, CONF_ssh_rekey_time);
11036 if (conf_get_int(ssh->conf, CONF_ssh_rekey_time) != rekey_time &&
11038 unsigned long new_next = ssh->last_rekey + rekey_time*60*TICKSPERSEC;
11039 unsigned long now = GETTICKCOUNT();
11041 if (now - ssh->last_rekey > rekey_time*60*TICKSPERSEC) {
11042 rekeying = "timeout shortened";
11044 ssh->next_rekey = schedule_timer(new_next - now, ssh2_timer, ssh);
11048 old_max_data_size = ssh->max_data_size;
11049 ssh->max_data_size = parse_blocksize(conf_get_str(ssh->conf,
11050 CONF_ssh_rekey_data));
11051 if (old_max_data_size != ssh->max_data_size &&
11052 ssh->max_data_size != 0) {
11053 if (ssh->outgoing_data_size > ssh->max_data_size ||
11054 ssh->incoming_data_size > ssh->max_data_size)
11055 rekeying = "data limit lowered";
11058 if (conf_get_int(ssh->conf, CONF_compression) !=
11059 conf_get_int(conf, CONF_compression)) {
11060 rekeying = "compression setting changed";
11061 rekey_mandatory = TRUE;
11064 for (i = 0; i < CIPHER_MAX; i++)
11065 if (conf_get_int_int(ssh->conf, CONF_ssh_cipherlist, i) !=
11066 conf_get_int_int(conf, CONF_ssh_cipherlist, i)) {
11067 rekeying = "cipher settings changed";
11068 rekey_mandatory = TRUE;
11070 if (conf_get_int(ssh->conf, CONF_ssh2_des_cbc) !=
11071 conf_get_int(conf, CONF_ssh2_des_cbc)) {
11072 rekeying = "cipher settings changed";
11073 rekey_mandatory = TRUE;
11076 conf_free(ssh->conf);
11077 ssh->conf = conf_copy(conf);
11078 ssh_cache_conf_values(ssh);
11080 if (!ssh->bare_connection && rekeying) {
11081 if (!ssh->kex_in_progress) {
11082 do_ssh2_transport(ssh, rekeying, -1, NULL);
11083 } else if (rekey_mandatory) {
11084 ssh->deferred_rekey_reason = rekeying;
11090 * Called to send data down the SSH connection.
11092 static int ssh_send(void *handle, char *buf, int len)
11094 Ssh ssh = (Ssh) handle;
11096 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
11099 ssh->protocol(ssh, (unsigned char *)buf, len, 0);
11101 return ssh_sendbuffer(ssh);
11105 * Called to query the current amount of buffered stdin data.
11107 static int ssh_sendbuffer(void *handle)
11109 Ssh ssh = (Ssh) handle;
11110 int override_value;
11112 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
11116 * If the SSH socket itself has backed up, add the total backup
11117 * size on that to any individual buffer on the stdin channel.
11119 override_value = 0;
11120 if (ssh->throttled_all)
11121 override_value = ssh->overall_bufsize;
11123 if (ssh->version == 1) {
11124 return override_value;
11125 } else if (ssh->version == 2) {
11126 if (!ssh->mainchan)
11127 return override_value;
11129 return (override_value +
11130 bufchain_size(&ssh->mainchan->v.v2.outbuffer));
11137 * Called to set the size of the window from SSH's POV.
11139 static void ssh_size(void *handle, int width, int height)
11141 Ssh ssh = (Ssh) handle;
11142 struct Packet *pktout;
11144 ssh->term_width = width;
11145 ssh->term_height = height;
11147 switch (ssh->state) {
11148 case SSH_STATE_BEFORE_SIZE:
11149 case SSH_STATE_PREPACKET:
11150 case SSH_STATE_CLOSED:
11151 break; /* do nothing */
11152 case SSH_STATE_INTERMED:
11153 ssh->size_needed = TRUE; /* buffer for later */
11155 case SSH_STATE_SESSION:
11156 if (!conf_get_int(ssh->conf, CONF_nopty)) {
11157 if (ssh->version == 1) {
11158 send_packet(ssh, SSH1_CMSG_WINDOW_SIZE,
11159 PKT_INT, ssh->term_height,
11160 PKT_INT, ssh->term_width,
11161 PKT_INT, 0, PKT_INT, 0, PKT_END);
11162 } else if (ssh->mainchan) {
11163 pktout = ssh2_chanreq_init(ssh->mainchan, "window-change",
11165 ssh2_pkt_adduint32(pktout, ssh->term_width);
11166 ssh2_pkt_adduint32(pktout, ssh->term_height);
11167 ssh2_pkt_adduint32(pktout, 0);
11168 ssh2_pkt_adduint32(pktout, 0);
11169 ssh2_pkt_send(ssh, pktout);
11177 * Return a list of the special codes that make sense in this
11180 static const struct telnet_special *ssh_get_specials(void *handle)
11182 static const struct telnet_special ssh1_ignore_special[] = {
11183 {"IGNORE message", TS_NOP}
11185 static const struct telnet_special ssh2_ignore_special[] = {
11186 {"IGNORE message", TS_NOP},
11188 static const struct telnet_special ssh2_rekey_special[] = {
11189 {"Repeat key exchange", TS_REKEY},
11191 static const struct telnet_special ssh2_session_specials[] = {
11194 /* These are the signal names defined by RFC 4254.
11195 * They include all the ISO C signals, but are a subset of the POSIX
11196 * required signals. */
11197 {"SIGINT (Interrupt)", TS_SIGINT},
11198 {"SIGTERM (Terminate)", TS_SIGTERM},
11199 {"SIGKILL (Kill)", TS_SIGKILL},
11200 {"SIGQUIT (Quit)", TS_SIGQUIT},
11201 {"SIGHUP (Hangup)", TS_SIGHUP},
11202 {"More signals", TS_SUBMENU},
11203 {"SIGABRT", TS_SIGABRT}, {"SIGALRM", TS_SIGALRM},
11204 {"SIGFPE", TS_SIGFPE}, {"SIGILL", TS_SIGILL},
11205 {"SIGPIPE", TS_SIGPIPE}, {"SIGSEGV", TS_SIGSEGV},
11206 {"SIGUSR1", TS_SIGUSR1}, {"SIGUSR2", TS_SIGUSR2},
11207 {NULL, TS_EXITMENU}
11209 static const struct telnet_special specials_end[] = {
11210 {NULL, TS_EXITMENU}
11212 /* XXX review this length for any changes: */
11213 static struct telnet_special ssh_specials[lenof(ssh2_ignore_special) +
11214 lenof(ssh2_rekey_special) +
11215 lenof(ssh2_session_specials) +
11216 lenof(specials_end)];
11217 Ssh ssh = (Ssh) handle;
11219 #define ADD_SPECIALS(name) \
11221 assert((i + lenof(name)) <= lenof(ssh_specials)); \
11222 memcpy(&ssh_specials[i], name, sizeof name); \
11223 i += lenof(name); \
11226 if (ssh->version == 1) {
11227 /* Don't bother offering IGNORE if we've decided the remote
11228 * won't cope with it, since we wouldn't bother sending it if
11230 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE))
11231 ADD_SPECIALS(ssh1_ignore_special);
11232 } else if (ssh->version == 2) {
11233 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH2_IGNORE))
11234 ADD_SPECIALS(ssh2_ignore_special);
11235 if (!(ssh->remote_bugs & BUG_SSH2_REKEY) && !ssh->bare_connection)
11236 ADD_SPECIALS(ssh2_rekey_special);
11238 ADD_SPECIALS(ssh2_session_specials);
11239 } /* else we're not ready yet */
11242 ADD_SPECIALS(specials_end);
11243 return ssh_specials;
11247 #undef ADD_SPECIALS
11251 * Send special codes. TS_EOF is useful for `plink', so you
11252 * can send an EOF and collect resulting output (e.g. `plink
11255 static void ssh_special(void *handle, Telnet_Special code)
11257 Ssh ssh = (Ssh) handle;
11258 struct Packet *pktout;
11260 if (code == TS_EOF) {
11261 if (ssh->state != SSH_STATE_SESSION) {
11263 * Buffer the EOF in case we are pre-SESSION, so we can
11264 * send it as soon as we reach SESSION.
11266 if (code == TS_EOF)
11267 ssh->eof_needed = TRUE;
11270 if (ssh->version == 1) {
11271 send_packet(ssh, SSH1_CMSG_EOF, PKT_END);
11272 } else if (ssh->mainchan) {
11273 sshfwd_write_eof(ssh->mainchan);
11274 ssh->send_ok = 0; /* now stop trying to read from stdin */
11276 logevent("Sent EOF message");
11277 } else if (code == TS_PING || code == TS_NOP) {
11278 if (ssh->state == SSH_STATE_CLOSED
11279 || ssh->state == SSH_STATE_PREPACKET) return;
11280 if (ssh->version == 1) {
11281 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE))
11282 send_packet(ssh, SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
11284 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH2_IGNORE)) {
11285 pktout = ssh2_pkt_init(SSH2_MSG_IGNORE);
11286 ssh2_pkt_addstring_start(pktout);
11287 ssh2_pkt_send_noqueue(ssh, pktout);
11290 } else if (code == TS_REKEY) {
11291 if (!ssh->kex_in_progress && !ssh->bare_connection &&
11292 ssh->version == 2) {
11293 do_ssh2_transport(ssh, "at user request", -1, NULL);
11295 } else if (code == TS_BRK) {
11296 if (ssh->state == SSH_STATE_CLOSED
11297 || ssh->state == SSH_STATE_PREPACKET) return;
11298 if (ssh->version == 1) {
11299 logevent("Unable to send BREAK signal in SSH-1");
11300 } else if (ssh->mainchan) {
11301 pktout = ssh2_chanreq_init(ssh->mainchan, "break", NULL, NULL);
11302 ssh2_pkt_adduint32(pktout, 0); /* default break length */
11303 ssh2_pkt_send(ssh, pktout);
11306 /* Is is a POSIX signal? */
11307 char *signame = NULL;
11308 if (code == TS_SIGABRT) signame = "ABRT";
11309 if (code == TS_SIGALRM) signame = "ALRM";
11310 if (code == TS_SIGFPE) signame = "FPE";
11311 if (code == TS_SIGHUP) signame = "HUP";
11312 if (code == TS_SIGILL) signame = "ILL";
11313 if (code == TS_SIGINT) signame = "INT";
11314 if (code == TS_SIGKILL) signame = "KILL";
11315 if (code == TS_SIGPIPE) signame = "PIPE";
11316 if (code == TS_SIGQUIT) signame = "QUIT";
11317 if (code == TS_SIGSEGV) signame = "SEGV";
11318 if (code == TS_SIGTERM) signame = "TERM";
11319 if (code == TS_SIGUSR1) signame = "USR1";
11320 if (code == TS_SIGUSR2) signame = "USR2";
11321 /* The SSH-2 protocol does in principle support arbitrary named
11322 * signals, including signame@domain, but we don't support those. */
11324 /* It's a signal. */
11325 if (ssh->version == 2 && ssh->mainchan) {
11326 pktout = ssh2_chanreq_init(ssh->mainchan, "signal", NULL, NULL);
11327 ssh2_pkt_addstring(pktout, signame);
11328 ssh2_pkt_send(ssh, pktout);
11329 logeventf(ssh, "Sent signal SIG%s", signame);
11332 /* Never heard of it. Do nothing */
11337 void *new_sock_channel(void *handle, struct PortForwarding *pf)
11339 Ssh ssh = (Ssh) handle;
11340 struct ssh_channel *c;
11341 c = snew(struct ssh_channel);
11344 ssh2_channel_init(c);
11345 c->halfopen = TRUE;
11346 c->type = CHAN_SOCKDATA_DORMANT;/* identify channel type */
11348 add234(ssh->channels, c);
11352 unsigned ssh_alloc_sharing_channel(Ssh ssh, void *sharing_ctx)
11354 struct ssh_channel *c;
11355 c = snew(struct ssh_channel);
11358 ssh2_channel_init(c);
11359 c->type = CHAN_SHARING;
11360 c->u.sharing.ctx = sharing_ctx;
11361 add234(ssh->channels, c);
11365 void ssh_delete_sharing_channel(Ssh ssh, unsigned localid)
11367 struct ssh_channel *c;
11369 c = find234(ssh->channels, &localid, ssh_channelfind);
11371 ssh_channel_destroy(c);
11374 void ssh_send_packet_from_downstream(Ssh ssh, unsigned id, int type,
11375 const void *data, int datalen,
11376 const char *additional_log_text)
11378 struct Packet *pkt;
11380 pkt = ssh2_pkt_init(type);
11381 pkt->downstream_id = id;
11382 pkt->additional_log_text = additional_log_text;
11383 ssh2_pkt_adddata(pkt, data, datalen);
11384 ssh2_pkt_send(ssh, pkt);
11388 * This is called when stdout/stderr (the entity to which
11389 * from_backend sends data) manages to clear some backlog.
11391 static void ssh_unthrottle(void *handle, int bufsize)
11393 Ssh ssh = (Ssh) handle;
11396 if (ssh->version == 1) {
11397 if (ssh->v1_stdout_throttling && bufsize < SSH1_BUFFER_LIMIT) {
11398 ssh->v1_stdout_throttling = 0;
11399 ssh_throttle_conn(ssh, -1);
11402 if (ssh->mainchan) {
11403 ssh2_set_window(ssh->mainchan,
11404 bufsize < ssh->mainchan->v.v2.locmaxwin ?
11405 ssh->mainchan->v.v2.locmaxwin - bufsize : 0);
11406 if (ssh_is_simple(ssh))
11409 buflimit = ssh->mainchan->v.v2.locmaxwin;
11410 if (ssh->mainchan->throttling_conn && bufsize <= buflimit) {
11411 ssh->mainchan->throttling_conn = 0;
11412 ssh_throttle_conn(ssh, -1);
11418 * Now process any SSH connection data that was stashed in our
11419 * queue while we were frozen.
11421 ssh_process_queued_incoming_data(ssh);
11424 void ssh_send_port_open(void *channel, char *hostname, int port, char *org)
11426 struct ssh_channel *c = (struct ssh_channel *)channel;
11428 struct Packet *pktout;
11430 logeventf(ssh, "Opening connection to %s:%d for %s", hostname, port, org);
11432 if (ssh->version == 1) {
11433 send_packet(ssh, SSH1_MSG_PORT_OPEN,
11434 PKT_INT, c->localid,
11437 /* PKT_STR, <org:orgport>, */
11440 pktout = ssh2_chanopen_init(c, "direct-tcpip");
11442 char *trimmed_host = host_strduptrim(hostname);
11443 ssh2_pkt_addstring(pktout, trimmed_host);
11444 sfree(trimmed_host);
11446 ssh2_pkt_adduint32(pktout, port);
11448 * We make up values for the originator data; partly it's
11449 * too much hassle to keep track, and partly I'm not
11450 * convinced the server should be told details like that
11451 * about my local network configuration.
11452 * The "originator IP address" is syntactically a numeric
11453 * IP address, and some servers (e.g., Tectia) get upset
11454 * if it doesn't match this syntax.
11456 ssh2_pkt_addstring(pktout, "0.0.0.0");
11457 ssh2_pkt_adduint32(pktout, 0);
11458 ssh2_pkt_send(ssh, pktout);
11462 static int ssh_connected(void *handle)
11464 Ssh ssh = (Ssh) handle;
11465 return ssh->s != NULL;
11468 static int ssh_sendok(void *handle)
11470 Ssh ssh = (Ssh) handle;
11471 return ssh->send_ok;
11474 static int ssh_ldisc(void *handle, int option)
11476 Ssh ssh = (Ssh) handle;
11477 if (option == LD_ECHO)
11478 return ssh->echoing;
11479 if (option == LD_EDIT)
11480 return ssh->editing;
11484 static void ssh_provide_ldisc(void *handle, void *ldisc)
11486 Ssh ssh = (Ssh) handle;
11487 ssh->ldisc = ldisc;
11490 static void ssh_provide_logctx(void *handle, void *logctx)
11492 Ssh ssh = (Ssh) handle;
11493 ssh->logctx = logctx;
11496 static int ssh_return_exitcode(void *handle)
11498 Ssh ssh = (Ssh) handle;
11499 if (ssh->s != NULL)
11502 return (ssh->exitcode >= 0 ? ssh->exitcode : INT_MAX);
11506 * cfg_info for SSH is the protocol running in this session.
11507 * (1 or 2 for the full SSH-1 or SSH-2 protocol; -1 for the bare
11508 * SSH-2 connection protocol, i.e. a downstream; 0 for not-decided-yet.)
11510 static int ssh_cfg_info(void *handle)
11512 Ssh ssh = (Ssh) handle;
11513 if (ssh->version == 0)
11514 return 0; /* don't know yet */
11515 else if (ssh->bare_connection)
11518 return ssh->version;
11522 * Gross hack: pscp will try to start SFTP but fall back to scp1 if
11523 * that fails. This variable is the means by which scp.c can reach
11524 * into the SSH code and find out which one it got.
11526 extern int ssh_fallback_cmd(void *handle)
11528 Ssh ssh = (Ssh) handle;
11529 return ssh->fallback_cmd;
11532 Backend ssh_backend = {
11542 ssh_return_exitcode,
11546 ssh_provide_logctx,