28 * Packet type contexts, so that ssh2_pkt_type can correctly decode
29 * the ambiguous type numbers back into the correct type strings.
40 SSH2_PKTCTX_PUBLICKEY,
46 static const char *const ssh2_disconnect_reasons[] = {
48 "host not allowed to connect",
50 "key exchange failed",
51 "host authentication failed",
54 "service not available",
55 "protocol version not supported",
56 "host key not verifiable",
59 "too many connections",
60 "auth cancelled by user",
61 "no more auth methods available",
66 * Various remote-bug flags.
68 #define BUG_CHOKES_ON_SSH1_IGNORE 1
69 #define BUG_SSH2_HMAC 2
70 #define BUG_NEEDS_SSH1_PLAIN_PASSWORD 4
71 #define BUG_CHOKES_ON_RSA 8
72 #define BUG_SSH2_RSA_PADDING 16
73 #define BUG_SSH2_DERIVEKEY 32
74 #define BUG_SSH2_REKEY 64
75 #define BUG_SSH2_PK_SESSIONID 128
76 #define BUG_SSH2_MAXPKT 256
77 #define BUG_CHOKES_ON_SSH2_IGNORE 512
78 #define BUG_CHOKES_ON_WINADJ 1024
79 #define BUG_SENDS_LATE_REQUEST_REPLY 2048
80 #define BUG_SSH2_OLDGEX 4096
82 #define DH_MIN_SIZE 1024
83 #define DH_MAX_SIZE 8192
86 * Codes for terminal modes.
87 * Most of these are the same in SSH-1 and SSH-2.
88 * This list is derived from RFC 4254 and
92 const char* const mode;
94 enum { TTY_OP_CHAR, TTY_OP_BOOL } type;
96 /* "V" prefix discarded for special characters relative to SSH specs */
97 { "INTR", 1, TTY_OP_CHAR },
98 { "QUIT", 2, TTY_OP_CHAR },
99 { "ERASE", 3, TTY_OP_CHAR },
100 { "KILL", 4, TTY_OP_CHAR },
101 { "EOF", 5, TTY_OP_CHAR },
102 { "EOL", 6, TTY_OP_CHAR },
103 { "EOL2", 7, TTY_OP_CHAR },
104 { "START", 8, TTY_OP_CHAR },
105 { "STOP", 9, TTY_OP_CHAR },
106 { "SUSP", 10, TTY_OP_CHAR },
107 { "DSUSP", 11, TTY_OP_CHAR },
108 { "REPRINT", 12, TTY_OP_CHAR },
109 { "WERASE", 13, TTY_OP_CHAR },
110 { "LNEXT", 14, TTY_OP_CHAR },
111 { "FLUSH", 15, TTY_OP_CHAR },
112 { "SWTCH", 16, TTY_OP_CHAR },
113 { "STATUS", 17, TTY_OP_CHAR },
114 { "DISCARD", 18, TTY_OP_CHAR },
115 { "IGNPAR", 30, TTY_OP_BOOL },
116 { "PARMRK", 31, TTY_OP_BOOL },
117 { "INPCK", 32, TTY_OP_BOOL },
118 { "ISTRIP", 33, TTY_OP_BOOL },
119 { "INLCR", 34, TTY_OP_BOOL },
120 { "IGNCR", 35, TTY_OP_BOOL },
121 { "ICRNL", 36, TTY_OP_BOOL },
122 { "IUCLC", 37, TTY_OP_BOOL },
123 { "IXON", 38, TTY_OP_BOOL },
124 { "IXANY", 39, TTY_OP_BOOL },
125 { "IXOFF", 40, TTY_OP_BOOL },
126 { "IMAXBEL", 41, TTY_OP_BOOL },
127 { "ISIG", 50, TTY_OP_BOOL },
128 { "ICANON", 51, TTY_OP_BOOL },
129 { "XCASE", 52, TTY_OP_BOOL },
130 { "ECHO", 53, TTY_OP_BOOL },
131 { "ECHOE", 54, TTY_OP_BOOL },
132 { "ECHOK", 55, TTY_OP_BOOL },
133 { "ECHONL", 56, TTY_OP_BOOL },
134 { "NOFLSH", 57, TTY_OP_BOOL },
135 { "TOSTOP", 58, TTY_OP_BOOL },
136 { "IEXTEN", 59, TTY_OP_BOOL },
137 { "ECHOCTL", 60, TTY_OP_BOOL },
138 { "ECHOKE", 61, TTY_OP_BOOL },
139 { "PENDIN", 62, TTY_OP_BOOL }, /* XXX is this a real mode? */
140 { "OPOST", 70, TTY_OP_BOOL },
141 { "OLCUC", 71, TTY_OP_BOOL },
142 { "ONLCR", 72, TTY_OP_BOOL },
143 { "OCRNL", 73, TTY_OP_BOOL },
144 { "ONOCR", 74, TTY_OP_BOOL },
145 { "ONLRET", 75, TTY_OP_BOOL },
146 { "CS7", 90, TTY_OP_BOOL },
147 { "CS8", 91, TTY_OP_BOOL },
148 { "PARENB", 92, TTY_OP_BOOL },
149 { "PARODD", 93, TTY_OP_BOOL }
152 /* Miscellaneous other tty-related constants. */
153 #define SSH_TTY_OP_END 0
154 /* The opcodes for ISPEED/OSPEED differ between SSH-1 and SSH-2. */
155 #define SSH1_TTY_OP_ISPEED 192
156 #define SSH1_TTY_OP_OSPEED 193
157 #define SSH2_TTY_OP_ISPEED 128
158 #define SSH2_TTY_OP_OSPEED 129
160 /* Helper functions for parsing tty-related config. */
161 static unsigned int ssh_tty_parse_specchar(char *s)
166 ret = ctrlparse(s, &next);
167 if (!next) ret = s[0];
169 ret = 255; /* special value meaning "don't set" */
173 static unsigned int ssh_tty_parse_boolean(char *s)
175 if (stricmp(s, "yes") == 0 ||
176 stricmp(s, "on") == 0 ||
177 stricmp(s, "true") == 0 ||
178 stricmp(s, "+") == 0)
180 else if (stricmp(s, "no") == 0 ||
181 stricmp(s, "off") == 0 ||
182 stricmp(s, "false") == 0 ||
183 stricmp(s, "-") == 0)
184 return 0; /* false */
186 return (atoi(s) != 0);
189 #define translate(x) if (type == x) return #x
190 #define translatek(x,ctx) if (type == x && (pkt_kctx == ctx)) return #x
191 #define translatea(x,ctx) if (type == x && (pkt_actx == ctx)) return #x
192 static const char *ssh1_pkt_type(int type)
194 translate(SSH1_MSG_DISCONNECT);
195 translate(SSH1_SMSG_PUBLIC_KEY);
196 translate(SSH1_CMSG_SESSION_KEY);
197 translate(SSH1_CMSG_USER);
198 translate(SSH1_CMSG_AUTH_RSA);
199 translate(SSH1_SMSG_AUTH_RSA_CHALLENGE);
200 translate(SSH1_CMSG_AUTH_RSA_RESPONSE);
201 translate(SSH1_CMSG_AUTH_PASSWORD);
202 translate(SSH1_CMSG_REQUEST_PTY);
203 translate(SSH1_CMSG_WINDOW_SIZE);
204 translate(SSH1_CMSG_EXEC_SHELL);
205 translate(SSH1_CMSG_EXEC_CMD);
206 translate(SSH1_SMSG_SUCCESS);
207 translate(SSH1_SMSG_FAILURE);
208 translate(SSH1_CMSG_STDIN_DATA);
209 translate(SSH1_SMSG_STDOUT_DATA);
210 translate(SSH1_SMSG_STDERR_DATA);
211 translate(SSH1_CMSG_EOF);
212 translate(SSH1_SMSG_EXIT_STATUS);
213 translate(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION);
214 translate(SSH1_MSG_CHANNEL_OPEN_FAILURE);
215 translate(SSH1_MSG_CHANNEL_DATA);
216 translate(SSH1_MSG_CHANNEL_CLOSE);
217 translate(SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION);
218 translate(SSH1_SMSG_X11_OPEN);
219 translate(SSH1_CMSG_PORT_FORWARD_REQUEST);
220 translate(SSH1_MSG_PORT_OPEN);
221 translate(SSH1_CMSG_AGENT_REQUEST_FORWARDING);
222 translate(SSH1_SMSG_AGENT_OPEN);
223 translate(SSH1_MSG_IGNORE);
224 translate(SSH1_CMSG_EXIT_CONFIRMATION);
225 translate(SSH1_CMSG_X11_REQUEST_FORWARDING);
226 translate(SSH1_CMSG_AUTH_RHOSTS_RSA);
227 translate(SSH1_MSG_DEBUG);
228 translate(SSH1_CMSG_REQUEST_COMPRESSION);
229 translate(SSH1_CMSG_AUTH_TIS);
230 translate(SSH1_SMSG_AUTH_TIS_CHALLENGE);
231 translate(SSH1_CMSG_AUTH_TIS_RESPONSE);
232 translate(SSH1_CMSG_AUTH_CCARD);
233 translate(SSH1_SMSG_AUTH_CCARD_CHALLENGE);
234 translate(SSH1_CMSG_AUTH_CCARD_RESPONSE);
237 static const char *ssh2_pkt_type(Pkt_KCtx pkt_kctx, Pkt_ACtx pkt_actx,
240 translatea(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE,SSH2_PKTCTX_GSSAPI);
241 translatea(SSH2_MSG_USERAUTH_GSSAPI_TOKEN,SSH2_PKTCTX_GSSAPI);
242 translatea(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE,SSH2_PKTCTX_GSSAPI);
243 translatea(SSH2_MSG_USERAUTH_GSSAPI_ERROR,SSH2_PKTCTX_GSSAPI);
244 translatea(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK,SSH2_PKTCTX_GSSAPI);
245 translatea(SSH2_MSG_USERAUTH_GSSAPI_MIC, SSH2_PKTCTX_GSSAPI);
246 translate(SSH2_MSG_DISCONNECT);
247 translate(SSH2_MSG_IGNORE);
248 translate(SSH2_MSG_UNIMPLEMENTED);
249 translate(SSH2_MSG_DEBUG);
250 translate(SSH2_MSG_SERVICE_REQUEST);
251 translate(SSH2_MSG_SERVICE_ACCEPT);
252 translate(SSH2_MSG_KEXINIT);
253 translate(SSH2_MSG_NEWKEYS);
254 translatek(SSH2_MSG_KEXDH_INIT, SSH2_PKTCTX_DHGROUP);
255 translatek(SSH2_MSG_KEXDH_REPLY, SSH2_PKTCTX_DHGROUP);
256 translatek(SSH2_MSG_KEX_DH_GEX_REQUEST_OLD, SSH2_PKTCTX_DHGEX);
257 translatek(SSH2_MSG_KEX_DH_GEX_REQUEST, SSH2_PKTCTX_DHGEX);
258 translatek(SSH2_MSG_KEX_DH_GEX_GROUP, SSH2_PKTCTX_DHGEX);
259 translatek(SSH2_MSG_KEX_DH_GEX_INIT, SSH2_PKTCTX_DHGEX);
260 translatek(SSH2_MSG_KEX_DH_GEX_REPLY, SSH2_PKTCTX_DHGEX);
261 translatek(SSH2_MSG_KEXRSA_PUBKEY, SSH2_PKTCTX_RSAKEX);
262 translatek(SSH2_MSG_KEXRSA_SECRET, SSH2_PKTCTX_RSAKEX);
263 translatek(SSH2_MSG_KEXRSA_DONE, SSH2_PKTCTX_RSAKEX);
264 translatek(SSH2_MSG_KEX_ECDH_INIT, SSH2_PKTCTX_ECDHKEX);
265 translatek(SSH2_MSG_KEX_ECDH_REPLY, SSH2_PKTCTX_ECDHKEX);
266 translate(SSH2_MSG_USERAUTH_REQUEST);
267 translate(SSH2_MSG_USERAUTH_FAILURE);
268 translate(SSH2_MSG_USERAUTH_SUCCESS);
269 translate(SSH2_MSG_USERAUTH_BANNER);
270 translatea(SSH2_MSG_USERAUTH_PK_OK, SSH2_PKTCTX_PUBLICKEY);
271 translatea(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, SSH2_PKTCTX_PASSWORD);
272 translatea(SSH2_MSG_USERAUTH_INFO_REQUEST, SSH2_PKTCTX_KBDINTER);
273 translatea(SSH2_MSG_USERAUTH_INFO_RESPONSE, SSH2_PKTCTX_KBDINTER);
274 translate(SSH2_MSG_GLOBAL_REQUEST);
275 translate(SSH2_MSG_REQUEST_SUCCESS);
276 translate(SSH2_MSG_REQUEST_FAILURE);
277 translate(SSH2_MSG_CHANNEL_OPEN);
278 translate(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
279 translate(SSH2_MSG_CHANNEL_OPEN_FAILURE);
280 translate(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
281 translate(SSH2_MSG_CHANNEL_DATA);
282 translate(SSH2_MSG_CHANNEL_EXTENDED_DATA);
283 translate(SSH2_MSG_CHANNEL_EOF);
284 translate(SSH2_MSG_CHANNEL_CLOSE);
285 translate(SSH2_MSG_CHANNEL_REQUEST);
286 translate(SSH2_MSG_CHANNEL_SUCCESS);
287 translate(SSH2_MSG_CHANNEL_FAILURE);
293 /* Enumeration values for fields in SSH-1 packets */
295 PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR, PKT_BIGNUM,
299 * Coroutine mechanics for the sillier bits of the code. If these
300 * macros look impenetrable to you, you might find it helpful to
303 * http://www.chiark.greenend.org.uk/~sgtatham/coroutines.html
305 * which explains the theory behind these macros.
307 * In particular, if you are getting `case expression not constant'
308 * errors when building with MS Visual Studio, this is because MS's
309 * Edit and Continue debugging feature causes their compiler to
310 * violate ANSI C. To disable Edit and Continue debugging:
312 * - right-click ssh.c in the FileView
314 * - select the C/C++ tab and the General category
315 * - under `Debug info:', select anything _other_ than `Program
316 * Database for Edit and Continue'.
318 #define crBegin(v) { int *crLine = &v; switch(v) { case 0:;
319 #define crBeginState crBegin(s->crLine)
320 #define crStateP(t, v) \
322 if (!(v)) { s = (v) = snew(struct t); s->crLine = 0; } \
324 #define crState(t) crStateP(t, ssh->t)
325 #define crFinish(z) } *crLine = 0; return (z); }
326 #define crFinishV } *crLine = 0; return; }
327 #define crFinishFree(z) } sfree(s); return (z); }
328 #define crFinishFreeV } sfree(s); return; }
329 #define crReturn(z) \
331 *crLine =__LINE__; return (z); case __LINE__:;\
335 *crLine=__LINE__; return; case __LINE__:;\
337 #define crStop(z) do{ *crLine = 0; return (z); }while(0)
338 #define crStopV do{ *crLine = 0; return; }while(0)
339 #define crWaitUntil(c) do { crReturn(0); } while (!(c))
340 #define crWaitUntilV(c) do { crReturnV; } while (!(c))
344 static struct Packet *ssh1_pkt_init(int pkt_type);
345 static struct Packet *ssh2_pkt_init(int pkt_type);
346 static void ssh_pkt_ensure(struct Packet *, int length);
347 static void ssh_pkt_adddata(struct Packet *, const void *data, int len);
348 static void ssh_pkt_addbyte(struct Packet *, unsigned char value);
349 static void ssh2_pkt_addbool(struct Packet *, unsigned char value);
350 static void ssh_pkt_adduint32(struct Packet *, unsigned long value);
351 static void ssh_pkt_addstring_start(struct Packet *);
352 static void ssh_pkt_addstring_str(struct Packet *, const char *data);
353 static void ssh_pkt_addstring_data(struct Packet *, const char *data, int len);
354 static void ssh_pkt_addstring(struct Packet *, const char *data);
355 static unsigned char *ssh2_mpint_fmt(Bignum b, int *len);
356 static void ssh1_pkt_addmp(struct Packet *, Bignum b);
357 static void ssh2_pkt_addmp(struct Packet *, Bignum b);
358 static int ssh2_pkt_construct(Ssh, struct Packet *);
359 static void ssh2_pkt_send(Ssh, struct Packet *);
360 static void ssh2_pkt_send_noqueue(Ssh, struct Packet *);
361 static int do_ssh1_login(Ssh ssh, const unsigned char *in, int inlen,
362 struct Packet *pktin);
363 static void do_ssh2_authconn(Ssh ssh, const unsigned char *in, int inlen,
364 struct Packet *pktin);
365 static void ssh2_channel_check_close(struct ssh_channel *c);
366 static void ssh_channel_destroy(struct ssh_channel *c);
369 * Buffer management constants. There are several of these for
370 * various different purposes:
372 * - SSH1_BUFFER_LIMIT is the amount of backlog that must build up
373 * on a local data stream before we throttle the whole SSH
374 * connection (in SSH-1 only). Throttling the whole connection is
375 * pretty drastic so we set this high in the hope it won't
378 * - SSH_MAX_BACKLOG is the amount of backlog that must build up
379 * on the SSH connection itself before we defensively throttle
380 * _all_ local data streams. This is pretty drastic too (though
381 * thankfully unlikely in SSH-2 since the window mechanism should
382 * ensure that the server never has any need to throttle its end
383 * of the connection), so we set this high as well.
385 * - OUR_V2_WINSIZE is the maximum window size we present on SSH-2
388 * - OUR_V2_BIGWIN is the window size we advertise for the only
389 * channel in a simple connection. It must be <= INT_MAX.
391 * - OUR_V2_MAXPKT is the official "maximum packet size" we send
392 * to the remote side. This actually has nothing to do with the
393 * size of the _packet_, but is instead a limit on the amount
394 * of data we're willing to receive in a single SSH2 channel
397 * - OUR_V2_PACKETLIMIT is actually the maximum size of SSH
398 * _packet_ we're prepared to cope with. It must be a multiple
399 * of the cipher block size, and must be at least 35000.
402 #define SSH1_BUFFER_LIMIT 32768
403 #define SSH_MAX_BACKLOG 32768
404 #define OUR_V2_WINSIZE 16384
405 #define OUR_V2_BIGWIN 0x7fffffff
406 #define OUR_V2_MAXPKT 0x4000UL
407 #define OUR_V2_PACKETLIMIT 0x9000UL
409 const static struct ssh_signkey *hostkey_algs[] = {
411 &ssh_ecdsa_nistp256, &ssh_ecdsa_nistp384, &ssh_ecdsa_nistp521,
415 const static struct ssh_mac *macs[] = {
416 &ssh_hmac_sha256, &ssh_hmac_sha1, &ssh_hmac_sha1_96, &ssh_hmac_md5
418 const static struct ssh_mac *buggymacs[] = {
419 &ssh_hmac_sha1_buggy, &ssh_hmac_sha1_96_buggy, &ssh_hmac_md5
422 static void *ssh_comp_none_init(void)
426 static void ssh_comp_none_cleanup(void *handle)
429 static int ssh_comp_none_block(void *handle, unsigned char *block, int len,
430 unsigned char **outblock, int *outlen)
434 static int ssh_comp_none_disable(void *handle)
438 const static struct ssh_compress ssh_comp_none = {
440 ssh_comp_none_init, ssh_comp_none_cleanup, ssh_comp_none_block,
441 ssh_comp_none_init, ssh_comp_none_cleanup, ssh_comp_none_block,
442 ssh_comp_none_disable, NULL
444 extern const struct ssh_compress ssh_zlib;
445 const static struct ssh_compress *compressions[] = {
446 &ssh_zlib, &ssh_comp_none
449 enum { /* channel types */
454 CHAN_SOCKDATA_DORMANT, /* one the remote hasn't confirmed */
456 * CHAN_SHARING indicates a channel which is tracked here on
457 * behalf of a connection-sharing downstream. We do almost nothing
458 * with these channels ourselves: all messages relating to them
459 * get thrown straight to sshshare.c and passed on almost
460 * unmodified to downstream.
464 * CHAN_ZOMBIE is used to indicate a channel for which we've
465 * already destroyed the local data source: for instance, if a
466 * forwarded port experiences a socket error on the local side, we
467 * immediately destroy its local socket and turn the SSH channel
473 typedef void (*handler_fn_t)(Ssh ssh, struct Packet *pktin);
474 typedef void (*chandler_fn_t)(Ssh ssh, struct Packet *pktin, void *ctx);
475 typedef void (*cchandler_fn_t)(struct ssh_channel *, struct Packet *, void *);
478 * Each channel has a queue of outstanding CHANNEL_REQUESTS and their
481 struct outstanding_channel_request {
482 cchandler_fn_t handler;
484 struct outstanding_channel_request *next;
488 * 2-3-4 tree storing channels.
491 Ssh ssh; /* pointer back to main context */
492 unsigned remoteid, localid;
494 /* True if we opened this channel but server hasn't confirmed. */
497 * In SSH-1, this value contains four bits:
499 * 1 We have sent SSH1_MSG_CHANNEL_CLOSE.
500 * 2 We have sent SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION.
501 * 4 We have received SSH1_MSG_CHANNEL_CLOSE.
502 * 8 We have received SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION.
504 * A channel is completely finished with when all four bits are set.
506 * In SSH-2, the four bits mean:
508 * 1 We have sent SSH2_MSG_CHANNEL_EOF.
509 * 2 We have sent SSH2_MSG_CHANNEL_CLOSE.
510 * 4 We have received SSH2_MSG_CHANNEL_EOF.
511 * 8 We have received SSH2_MSG_CHANNEL_CLOSE.
513 * A channel is completely finished with when we have both sent
514 * and received CLOSE.
516 * The symbolic constants below use the SSH-2 terminology, which
517 * is a bit confusing in SSH-1, but we have to use _something_.
519 #define CLOSES_SENT_EOF 1
520 #define CLOSES_SENT_CLOSE 2
521 #define CLOSES_RCVD_EOF 4
522 #define CLOSES_RCVD_CLOSE 8
526 * This flag indicates that an EOF is pending on the outgoing side
527 * of the channel: that is, wherever we're getting the data for
528 * this channel has sent us some data followed by EOF. We can't
529 * actually send the EOF until we've finished sending the data, so
530 * we set this flag instead to remind us to do so once our buffer
536 * True if this channel is causing the underlying connection to be
541 struct ssh2_data_channel {
543 unsigned remwindow, remmaxpkt;
544 /* locwindow is signed so we can cope with excess data. */
545 int locwindow, locmaxwin;
547 * remlocwin is the amount of local window that we think
548 * the remote end had available to it after it sent the
549 * last data packet or window adjust ack.
553 * These store the list of channel requests that haven't
556 struct outstanding_channel_request *chanreq_head, *chanreq_tail;
557 enum { THROTTLED, UNTHROTTLING, UNTHROTTLED } throttle_state;
561 struct ssh_agent_channel {
562 unsigned char *message;
563 unsigned char msglen[4];
564 unsigned lensofar, totallen;
565 int outstanding_requests;
567 struct ssh_x11_channel {
568 struct X11Connection *xconn;
571 struct ssh_pfd_channel {
572 struct PortForwarding *pf;
574 struct ssh_sharing_channel {
581 * 2-3-4 tree storing remote->local port forwardings. SSH-1 and SSH-2
582 * use this structure in different ways, reflecting SSH-2's
583 * altogether saner approach to port forwarding.
585 * In SSH-1, you arrange a remote forwarding by sending the server
586 * the remote port number, and the local destination host:port.
587 * When a connection comes in, the server sends you back that
588 * host:port pair, and you connect to it. This is a ready-made
589 * security hole if you're not on the ball: a malicious server
590 * could send you back _any_ host:port pair, so if you trustingly
591 * connect to the address it gives you then you've just opened the
592 * entire inside of your corporate network just by connecting
593 * through it to a dodgy SSH server. Hence, we must store a list of
594 * host:port pairs we _are_ trying to forward to, and reject a
595 * connection request from the server if it's not in the list.
597 * In SSH-2, each side of the connection minds its own business and
598 * doesn't send unnecessary information to the other. You arrange a
599 * remote forwarding by sending the server just the remote port
600 * number. When a connection comes in, the server tells you which
601 * of its ports was connected to; and _you_ have to remember what
602 * local host:port pair went with that port number.
604 * Hence, in SSH-1 this structure is indexed by destination
605 * host:port pair, whereas in SSH-2 it is indexed by source port.
607 struct ssh_portfwd; /* forward declaration */
609 struct ssh_rportfwd {
610 unsigned sport, dport;
614 struct ssh_portfwd *pfrec;
617 static void free_rportfwd(struct ssh_rportfwd *pf)
620 sfree(pf->sportdesc);
628 * Separately to the rportfwd tree (which is for looking up port
629 * open requests from the server), a tree of _these_ structures is
630 * used to keep track of all the currently open port forwardings,
631 * so that we can reconfigure in mid-session if the user requests
635 enum { DESTROY, KEEP, CREATE } status;
637 unsigned sport, dport;
640 struct ssh_rportfwd *remote;
642 struct PortListener *local;
644 #define free_portfwd(pf) ( \
645 ((pf) ? (sfree((pf)->saddr), sfree((pf)->daddr), \
646 sfree((pf)->sserv), sfree((pf)->dserv)) : (void)0 ), sfree(pf) )
649 long length; /* length of packet: see below */
650 long forcepad; /* SSH-2: force padding to at least this length */
651 int type; /* only used for incoming packets */
652 unsigned long sequence; /* SSH-2 incoming sequence number */
653 unsigned char *data; /* allocated storage */
654 unsigned char *body; /* offset of payload within `data' */
655 long savedpos; /* dual-purpose saved packet position: see below */
656 long maxlen; /* amount of storage allocated for `data' */
657 long encrypted_len; /* for SSH-2 total-size counting */
660 * A note on the 'length' and 'savedpos' fields above.
662 * Incoming packets are set up so that pkt->length is measured
663 * relative to pkt->body, which itself points to a few bytes after
664 * pkt->data (skipping some uninteresting header fields including
665 * the packet type code). The ssh_pkt_get* functions all expect
666 * this setup, and they also use pkt->savedpos to indicate how far
667 * through the packet being decoded they've got - and that, too,
668 * is an offset from pkt->body rather than pkt->data.
670 * During construction of an outgoing packet, however, pkt->length
671 * is measured relative to the base pointer pkt->data, and
672 * pkt->body is not really used for anything until the packet is
673 * ready for sending. In this mode, pkt->savedpos is reused as a
674 * temporary variable by the addstring functions, which write out
675 * a string length field and then keep going back and updating it
676 * as more data is appended to the subsequent string data field;
677 * pkt->savedpos stores the offset (again relative to pkt->data)
678 * of the start of the string data field.
681 /* Extra metadata used in SSH packet logging mode, allowing us to
682 * log in the packet header line that the packet came from a
683 * connection-sharing downstream and what if anything unusual was
684 * done to it. The additional_log_text field is expected to be a
685 * static string - it will not be freed. */
686 unsigned downstream_id;
687 const char *additional_log_text;
690 static void ssh1_protocol(Ssh ssh, const void *vin, int inlen,
691 struct Packet *pktin);
692 static void ssh2_protocol(Ssh ssh, const void *vin, int inlen,
693 struct Packet *pktin);
694 static void ssh2_bare_connection_protocol(Ssh ssh, const void *vin, int inlen,
695 struct Packet *pktin);
696 static void ssh1_protocol_setup(Ssh ssh);
697 static void ssh2_protocol_setup(Ssh ssh);
698 static void ssh2_bare_connection_protocol_setup(Ssh ssh);
699 static void ssh_size(void *handle, int width, int height);
700 static void ssh_special(void *handle, Telnet_Special);
701 static int ssh2_try_send(struct ssh_channel *c);
702 static void ssh2_add_channel_data(struct ssh_channel *c,
703 const char *buf, int len);
704 static void ssh_throttle_all(Ssh ssh, int enable, int bufsize);
705 static void ssh2_set_window(struct ssh_channel *c, int newwin);
706 static int ssh_sendbuffer(void *handle);
707 static int ssh_do_close(Ssh ssh, int notify_exit);
708 static unsigned long ssh_pkt_getuint32(struct Packet *pkt);
709 static int ssh2_pkt_getbool(struct Packet *pkt);
710 static void ssh_pkt_getstring(struct Packet *pkt, char **p, int *length);
711 static void ssh2_timer(void *ctx, unsigned long now);
712 static void do_ssh2_transport(Ssh ssh, const void *vin, int inlen,
713 struct Packet *pktin);
714 static void ssh2_msg_unexpected(Ssh ssh, struct Packet *pktin);
716 struct rdpkt1_state_tag {
717 long len, pad, biglen, to_read;
718 unsigned long realcrc, gotcrc;
722 struct Packet *pktin;
725 struct rdpkt2_state_tag {
726 long len, pad, payload, packetlen, maclen;
729 unsigned long incoming_sequence;
730 struct Packet *pktin;
733 struct rdpkt2_bare_state_tag {
737 unsigned long incoming_sequence;
738 struct Packet *pktin;
741 struct queued_handler;
742 struct queued_handler {
744 chandler_fn_t handler;
746 struct queued_handler *next;
750 const struct plug_function_table *fn;
751 /* the above field _must_ be first in the structure */
761 unsigned char session_key[32];
763 int v1_remote_protoflags;
764 int v1_local_protoflags;
765 int agentfwd_enabled;
768 const struct ssh_cipher *cipher;
771 const struct ssh2_cipher *cscipher, *sccipher;
772 void *cs_cipher_ctx, *sc_cipher_ctx;
773 const struct ssh_mac *csmac, *scmac;
774 int csmac_etm, scmac_etm;
775 void *cs_mac_ctx, *sc_mac_ctx;
776 const struct ssh_compress *cscomp, *sccomp;
777 void *cs_comp_ctx, *sc_comp_ctx;
778 const struct ssh_kex *kex;
779 const struct ssh_signkey *hostkey;
780 char *hostkey_str; /* string representation, for easy checking in rekeys */
781 unsigned char v2_session_id[SSH2_KEX_MAX_HASH_LEN];
782 int v2_session_id_len;
786 int attempting_connshare;
792 int echoing, editing;
796 int ospeed, ispeed; /* temporaries */
797 int term_width, term_height;
799 tree234 *channels; /* indexed by local id */
800 struct ssh_channel *mainchan; /* primary session channel */
801 int ncmode; /* is primary channel direct-tcpip? */
806 tree234 *rportfwds, *portfwds;
810 SSH_STATE_BEFORE_SIZE,
816 int size_needed, eof_needed;
817 int sent_console_eof;
818 int got_pty; /* affects EOF behaviour on main channel */
820 struct Packet **queue;
821 int queuelen, queuesize;
823 unsigned char *deferred_send_data;
824 int deferred_len, deferred_size;
827 * Gross hack: pscp will try to start SFTP but fall back to
828 * scp1 if that fails. This variable is the means by which
829 * scp.c can reach into the SSH code and find out which one it
834 bufchain banner; /* accumulates banners during do_ssh2_authconn */
839 struct X11Display *x11disp;
840 struct X11FakeAuth *x11auth;
841 tree234 *x11authtree;
844 int conn_throttle_count;
847 int v1_stdout_throttling;
848 unsigned long v2_outgoing_sequence;
850 int ssh1_rdpkt_crstate;
851 int ssh2_rdpkt_crstate;
852 int ssh2_bare_rdpkt_crstate;
853 int ssh_gotdata_crstate;
854 int do_ssh1_connection_crstate;
856 void *do_ssh_init_state;
857 void *do_ssh1_login_state;
858 void *do_ssh2_transport_state;
859 void *do_ssh2_authconn_state;
860 void *do_ssh_connection_init_state;
862 struct rdpkt1_state_tag rdpkt1_state;
863 struct rdpkt2_state_tag rdpkt2_state;
864 struct rdpkt2_bare_state_tag rdpkt2_bare_state;
866 /* SSH-1 and SSH-2 use this for different things, but both use it */
867 int protocol_initial_phase_done;
869 void (*protocol) (Ssh ssh, const void *vin, int inlen,
871 struct Packet *(*s_rdpkt) (Ssh ssh, const unsigned char **data,
873 int (*do_ssh_init)(Ssh ssh, unsigned char c);
876 * We maintain our own copy of a Conf structure here. That way,
877 * when we're passed a new one for reconfiguration, we can check
878 * the differences and potentially reconfigure port forwardings
879 * etc in mid-session.
884 * Values cached out of conf so as to avoid the tree234 lookup
885 * cost every time they're used.
890 * Dynamically allocated username string created during SSH
891 * login. Stored in here rather than in the coroutine state so
892 * that it'll be reliably freed if we shut down the SSH session
893 * at some unexpected moment.
898 * Used to transfer data back from async callbacks.
900 void *agent_response;
901 int agent_response_len;
905 * The SSH connection can be set as `frozen', meaning we are
906 * not currently accepting incoming data from the network. This
907 * is slightly more serious than setting the _socket_ as
908 * frozen, because we may already have had data passed to us
909 * from the network which we need to delay processing until
910 * after the freeze is lifted, so we also need a bufchain to
914 bufchain queued_incoming_data;
917 * Dispatch table for packet types that we may have to deal
920 handler_fn_t packet_dispatch[256];
923 * Queues of one-off handler functions for success/failure
924 * indications from a request.
926 struct queued_handler *qhead, *qtail;
927 handler_fn_t q_saved_handler1, q_saved_handler2;
930 * This module deals with sending keepalives.
935 * Track incoming and outgoing data sizes and time, for
938 unsigned long incoming_data_size, outgoing_data_size, deferred_data_size;
939 unsigned long max_data_size;
941 unsigned long next_rekey, last_rekey;
942 const char *deferred_rekey_reason;
945 * Fully qualified host name, which we need if doing GSSAPI.
951 * GSSAPI libraries for this session.
953 struct ssh_gss_liblist *gsslibs;
957 #define logevent(s) logevent(ssh->frontend, s)
959 /* logevent, only printf-formatted. */
960 static void logeventf(Ssh ssh, const char *fmt, ...)
966 buf = dupvprintf(fmt, ap);
972 static void bomb_out(Ssh ssh, char *text)
974 ssh_do_close(ssh, FALSE);
976 connection_fatal(ssh->frontend, "%s", text);
980 #define bombout(msg) bomb_out(ssh, dupprintf msg)
982 /* Helper function for common bits of parsing ttymodes. */
983 static void parse_ttymodes(Ssh ssh,
984 void (*do_mode)(void *data, char *mode, char *val),
989 for (val = conf_get_str_strs(ssh->conf, CONF_ttymodes, NULL, &key);
991 val = conf_get_str_strs(ssh->conf, CONF_ttymodes, key, &key)) {
993 * val[0] is either 'V', indicating that an explicit value
994 * follows it, or 'A' indicating that we should pass the
995 * value through from the local environment via get_ttymode.
998 val = get_ttymode(ssh->frontend, key);
1000 do_mode(data, key, val);
1004 do_mode(data, key, val + 1); /* skip the 'V' */
1008 static int ssh_channelcmp(void *av, void *bv)
1010 struct ssh_channel *a = (struct ssh_channel *) av;
1011 struct ssh_channel *b = (struct ssh_channel *) bv;
1012 if (a->localid < b->localid)
1014 if (a->localid > b->localid)
1018 static int ssh_channelfind(void *av, void *bv)
1020 unsigned *a = (unsigned *) av;
1021 struct ssh_channel *b = (struct ssh_channel *) bv;
1022 if (*a < b->localid)
1024 if (*a > b->localid)
1029 static int ssh_rportcmp_ssh1(void *av, void *bv)
1031 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
1032 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
1034 if ( (i = strcmp(a->dhost, b->dhost)) != 0)
1035 return i < 0 ? -1 : +1;
1036 if (a->dport > b->dport)
1038 if (a->dport < b->dport)
1043 static int ssh_rportcmp_ssh2(void *av, void *bv)
1045 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
1046 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
1048 if ( (i = strcmp(a->shost, b->shost)) != 0)
1049 return i < 0 ? -1 : +1;
1050 if (a->sport > b->sport)
1052 if (a->sport < b->sport)
1058 * Special form of strcmp which can cope with NULL inputs. NULL is
1059 * defined to sort before even the empty string.
1061 static int nullstrcmp(const char *a, const char *b)
1063 if (a == NULL && b == NULL)
1069 return strcmp(a, b);
1072 static int ssh_portcmp(void *av, void *bv)
1074 struct ssh_portfwd *a = (struct ssh_portfwd *) av;
1075 struct ssh_portfwd *b = (struct ssh_portfwd *) bv;
1077 if (a->type > b->type)
1079 if (a->type < b->type)
1081 if (a->addressfamily > b->addressfamily)
1083 if (a->addressfamily < b->addressfamily)
1085 if ( (i = nullstrcmp(a->saddr, b->saddr)) != 0)
1086 return i < 0 ? -1 : +1;
1087 if (a->sport > b->sport)
1089 if (a->sport < b->sport)
1091 if (a->type != 'D') {
1092 if ( (i = nullstrcmp(a->daddr, b->daddr)) != 0)
1093 return i < 0 ? -1 : +1;
1094 if (a->dport > b->dport)
1096 if (a->dport < b->dport)
1102 static int alloc_channel_id(Ssh ssh)
1104 const unsigned CHANNEL_NUMBER_OFFSET = 256;
1105 unsigned low, high, mid;
1107 struct ssh_channel *c;
1110 * First-fit allocation of channel numbers: always pick the
1111 * lowest unused one. To do this, binary-search using the
1112 * counted B-tree to find the largest channel ID which is in a
1113 * contiguous sequence from the beginning. (Precisely
1114 * everything in that sequence must have ID equal to its tree
1115 * index plus CHANNEL_NUMBER_OFFSET.)
1117 tsize = count234(ssh->channels);
1121 while (high - low > 1) {
1122 mid = (high + low) / 2;
1123 c = index234(ssh->channels, mid);
1124 if (c->localid == mid + CHANNEL_NUMBER_OFFSET)
1125 low = mid; /* this one is fine */
1127 high = mid; /* this one is past it */
1130 * Now low points to either -1, or the tree index of the
1131 * largest ID in the initial sequence.
1134 unsigned i = low + 1 + CHANNEL_NUMBER_OFFSET;
1135 assert(NULL == find234(ssh->channels, &i, ssh_channelfind));
1137 return low + 1 + CHANNEL_NUMBER_OFFSET;
1140 static void c_write_stderr(int trusted, const char *buf, int len)
1143 for (i = 0; i < len; i++)
1144 if (buf[i] != '\r' && (trusted || buf[i] == '\n' || (buf[i] & 0x60)))
1145 fputc(buf[i], stderr);
1148 static void c_write(Ssh ssh, const char *buf, int len)
1150 if (flags & FLAG_STDERR)
1151 c_write_stderr(1, buf, len);
1153 from_backend(ssh->frontend, 1, buf, len);
1156 static void c_write_untrusted(Ssh ssh, const char *buf, int len)
1158 if (flags & FLAG_STDERR)
1159 c_write_stderr(0, buf, len);
1161 from_backend_untrusted(ssh->frontend, buf, len);
1164 static void c_write_str(Ssh ssh, const char *buf)
1166 c_write(ssh, buf, strlen(buf));
1169 static void ssh_free_packet(struct Packet *pkt)
1174 static struct Packet *ssh_new_packet(void)
1176 struct Packet *pkt = snew(struct Packet);
1178 pkt->body = pkt->data = NULL;
1184 static void ssh1_log_incoming_packet(Ssh ssh, struct Packet *pkt)
1187 struct logblank_t blanks[4];
1193 if (ssh->logomitdata &&
1194 (pkt->type == SSH1_SMSG_STDOUT_DATA ||
1195 pkt->type == SSH1_SMSG_STDERR_DATA ||
1196 pkt->type == SSH1_MSG_CHANNEL_DATA)) {
1197 /* "Session data" packets - omit the data string. */
1198 if (pkt->type == SSH1_MSG_CHANNEL_DATA)
1199 ssh_pkt_getuint32(pkt); /* skip channel id */
1200 blanks[nblanks].offset = pkt->savedpos + 4;
1201 blanks[nblanks].type = PKTLOG_OMIT;
1202 ssh_pkt_getstring(pkt, &str, &slen);
1204 blanks[nblanks].len = slen;
1208 log_packet(ssh->logctx, PKT_INCOMING, pkt->type,
1209 ssh1_pkt_type(pkt->type),
1210 pkt->body, pkt->length, nblanks, blanks, NULL,
1214 static void ssh1_log_outgoing_packet(Ssh ssh, struct Packet *pkt)
1217 struct logblank_t blanks[4];
1222 * For outgoing packets, pkt->length represents the length of the
1223 * whole packet starting at pkt->data (including some header), and
1224 * pkt->body refers to the point within that where the log-worthy
1225 * payload begins. However, incoming packets expect pkt->length to
1226 * represent only the payload length (that is, it's measured from
1227 * pkt->body not from pkt->data). Temporarily adjust our outgoing
1228 * packet to conform to the incoming-packet semantics, so that we
1229 * can analyse it with the ssh_pkt_get functions.
1231 pkt->length -= (pkt->body - pkt->data);
1234 if (ssh->logomitdata &&
1235 (pkt->type == SSH1_CMSG_STDIN_DATA ||
1236 pkt->type == SSH1_MSG_CHANNEL_DATA)) {
1237 /* "Session data" packets - omit the data string. */
1238 if (pkt->type == SSH1_MSG_CHANNEL_DATA)
1239 ssh_pkt_getuint32(pkt); /* skip channel id */
1240 blanks[nblanks].offset = pkt->savedpos + 4;
1241 blanks[nblanks].type = PKTLOG_OMIT;
1242 ssh_pkt_getstring(pkt, &str, &slen);
1244 blanks[nblanks].len = slen;
1249 if ((pkt->type == SSH1_CMSG_AUTH_PASSWORD ||
1250 pkt->type == SSH1_CMSG_AUTH_TIS_RESPONSE ||
1251 pkt->type == SSH1_CMSG_AUTH_CCARD_RESPONSE) &&
1252 conf_get_int(ssh->conf, CONF_logomitpass)) {
1253 /* If this is a password or similar packet, blank the password(s). */
1254 blanks[nblanks].offset = 0;
1255 blanks[nblanks].len = pkt->length;
1256 blanks[nblanks].type = PKTLOG_BLANK;
1258 } else if (pkt->type == SSH1_CMSG_X11_REQUEST_FORWARDING &&
1259 conf_get_int(ssh->conf, CONF_logomitpass)) {
1261 * If this is an X forwarding request packet, blank the fake
1264 * Note that while we blank the X authentication data here, we
1265 * don't take any special action to blank the start of an X11
1266 * channel, so using MIT-MAGIC-COOKIE-1 and actually opening
1267 * an X connection without having session blanking enabled is
1268 * likely to leak your cookie into the log.
1271 ssh_pkt_getstring(pkt, &str, &slen);
1272 blanks[nblanks].offset = pkt->savedpos;
1273 blanks[nblanks].type = PKTLOG_BLANK;
1274 ssh_pkt_getstring(pkt, &str, &slen);
1276 blanks[nblanks].len = pkt->savedpos - blanks[nblanks].offset;
1281 log_packet(ssh->logctx, PKT_OUTGOING, pkt->data[12],
1282 ssh1_pkt_type(pkt->data[12]),
1283 pkt->body, pkt->length,
1284 nblanks, blanks, NULL, 0, NULL);
1287 * Undo the above adjustment of pkt->length, to put the packet
1288 * back in the state we found it.
1290 pkt->length += (pkt->body - pkt->data);
1294 * Collect incoming data in the incoming packet buffer.
1295 * Decipher and verify the packet when it is completely read.
1296 * Drop SSH1_MSG_DEBUG and SSH1_MSG_IGNORE packets.
1297 * Update the *data and *datalen variables.
1298 * Return a Packet structure when a packet is completed.
1300 static struct Packet *ssh1_rdpkt(Ssh ssh, const unsigned char **data,
1303 struct rdpkt1_state_tag *st = &ssh->rdpkt1_state;
1305 crBegin(ssh->ssh1_rdpkt_crstate);
1307 st->pktin = ssh_new_packet();
1309 st->pktin->type = 0;
1310 st->pktin->length = 0;
1312 for (st->i = st->len = 0; st->i < 4; st->i++) {
1313 while ((*datalen) == 0)
1315 st->len = (st->len << 8) + **data;
1316 (*data)++, (*datalen)--;
1319 st->pad = 8 - (st->len % 8);
1320 st->biglen = st->len + st->pad;
1321 st->pktin->length = st->len - 5;
1323 if (st->biglen < 0) {
1324 bombout(("Extremely large packet length from server suggests"
1325 " data stream corruption"));
1326 ssh_free_packet(st->pktin);
1330 st->pktin->maxlen = st->biglen;
1331 st->pktin->data = snewn(st->biglen + APIEXTRA, unsigned char);
1333 st->to_read = st->biglen;
1334 st->p = st->pktin->data;
1335 while (st->to_read > 0) {
1336 st->chunk = st->to_read;
1337 while ((*datalen) == 0)
1339 if (st->chunk > (*datalen))
1340 st->chunk = (*datalen);
1341 memcpy(st->p, *data, st->chunk);
1343 *datalen -= st->chunk;
1345 st->to_read -= st->chunk;
1348 if (ssh->cipher && detect_attack(ssh->crcda_ctx, st->pktin->data,
1349 st->biglen, NULL)) {
1350 bombout(("Network attack (CRC compensation) detected!"));
1351 ssh_free_packet(st->pktin);
1356 ssh->cipher->decrypt(ssh->v1_cipher_ctx, st->pktin->data, st->biglen);
1358 st->realcrc = crc32_compute(st->pktin->data, st->biglen - 4);
1359 st->gotcrc = GET_32BIT(st->pktin->data + st->biglen - 4);
1360 if (st->gotcrc != st->realcrc) {
1361 bombout(("Incorrect CRC received on packet"));
1362 ssh_free_packet(st->pktin);
1366 st->pktin->body = st->pktin->data + st->pad + 1;
1368 if (ssh->v1_compressing) {
1369 unsigned char *decompblk;
1371 if (!zlib_decompress_block(ssh->sc_comp_ctx,
1372 st->pktin->body - 1, st->pktin->length + 1,
1373 &decompblk, &decomplen)) {
1374 bombout(("Zlib decompression encountered invalid data"));
1375 ssh_free_packet(st->pktin);
1379 if (st->pktin->maxlen < st->pad + decomplen) {
1380 st->pktin->maxlen = st->pad + decomplen;
1381 st->pktin->data = sresize(st->pktin->data,
1382 st->pktin->maxlen + APIEXTRA,
1384 st->pktin->body = st->pktin->data + st->pad + 1;
1387 memcpy(st->pktin->body - 1, decompblk, decomplen);
1389 st->pktin->length = decomplen - 1;
1392 st->pktin->type = st->pktin->body[-1];
1395 * Now pktin->body and pktin->length identify the semantic content
1396 * of the packet, excluding the initial type byte.
1400 ssh1_log_incoming_packet(ssh, st->pktin);
1402 st->pktin->savedpos = 0;
1404 crFinish(st->pktin);
1407 static void ssh2_log_incoming_packet(Ssh ssh, struct Packet *pkt)
1410 struct logblank_t blanks[4];
1416 if (ssh->logomitdata &&
1417 (pkt->type == SSH2_MSG_CHANNEL_DATA ||
1418 pkt->type == SSH2_MSG_CHANNEL_EXTENDED_DATA)) {
1419 /* "Session data" packets - omit the data string. */
1420 ssh_pkt_getuint32(pkt); /* skip channel id */
1421 if (pkt->type == SSH2_MSG_CHANNEL_EXTENDED_DATA)
1422 ssh_pkt_getuint32(pkt); /* skip extended data type */
1423 blanks[nblanks].offset = pkt->savedpos + 4;
1424 blanks[nblanks].type = PKTLOG_OMIT;
1425 ssh_pkt_getstring(pkt, &str, &slen);
1427 blanks[nblanks].len = slen;
1432 log_packet(ssh->logctx, PKT_INCOMING, pkt->type,
1433 ssh2_pkt_type(ssh->pkt_kctx, ssh->pkt_actx, pkt->type),
1434 pkt->body, pkt->length, nblanks, blanks, &pkt->sequence,
1438 static void ssh2_log_outgoing_packet(Ssh ssh, struct Packet *pkt)
1441 struct logblank_t blanks[4];
1446 * For outgoing packets, pkt->length represents the length of the
1447 * whole packet starting at pkt->data (including some header), and
1448 * pkt->body refers to the point within that where the log-worthy
1449 * payload begins. However, incoming packets expect pkt->length to
1450 * represent only the payload length (that is, it's measured from
1451 * pkt->body not from pkt->data). Temporarily adjust our outgoing
1452 * packet to conform to the incoming-packet semantics, so that we
1453 * can analyse it with the ssh_pkt_get functions.
1455 pkt->length -= (pkt->body - pkt->data);
1458 if (ssh->logomitdata &&
1459 (pkt->type == SSH2_MSG_CHANNEL_DATA ||
1460 pkt->type == SSH2_MSG_CHANNEL_EXTENDED_DATA)) {
1461 /* "Session data" packets - omit the data string. */
1462 ssh_pkt_getuint32(pkt); /* skip channel id */
1463 if (pkt->type == SSH2_MSG_CHANNEL_EXTENDED_DATA)
1464 ssh_pkt_getuint32(pkt); /* skip extended data type */
1465 blanks[nblanks].offset = pkt->savedpos + 4;
1466 blanks[nblanks].type = PKTLOG_OMIT;
1467 ssh_pkt_getstring(pkt, &str, &slen);
1469 blanks[nblanks].len = slen;
1474 if (pkt->type == SSH2_MSG_USERAUTH_REQUEST &&
1475 conf_get_int(ssh->conf, CONF_logomitpass)) {
1476 /* If this is a password packet, blank the password(s). */
1478 ssh_pkt_getstring(pkt, &str, &slen);
1479 ssh_pkt_getstring(pkt, &str, &slen);
1480 ssh_pkt_getstring(pkt, &str, &slen);
1481 if (slen == 8 && !memcmp(str, "password", 8)) {
1482 ssh2_pkt_getbool(pkt);
1483 /* Blank the password field. */
1484 blanks[nblanks].offset = pkt->savedpos;
1485 blanks[nblanks].type = PKTLOG_BLANK;
1486 ssh_pkt_getstring(pkt, &str, &slen);
1488 blanks[nblanks].len = pkt->savedpos - blanks[nblanks].offset;
1490 /* If there's another password field beyond it (change of
1491 * password), blank that too. */
1492 ssh_pkt_getstring(pkt, &str, &slen);
1494 blanks[nblanks-1].len =
1495 pkt->savedpos - blanks[nblanks].offset;
1498 } else if (ssh->pkt_actx == SSH2_PKTCTX_KBDINTER &&
1499 pkt->type == SSH2_MSG_USERAUTH_INFO_RESPONSE &&
1500 conf_get_int(ssh->conf, CONF_logomitpass)) {
1501 /* If this is a keyboard-interactive response packet, blank
1504 ssh_pkt_getuint32(pkt);
1505 blanks[nblanks].offset = pkt->savedpos;
1506 blanks[nblanks].type = PKTLOG_BLANK;
1508 ssh_pkt_getstring(pkt, &str, &slen);
1512 blanks[nblanks].len = pkt->savedpos - blanks[nblanks].offset;
1514 } else if (pkt->type == SSH2_MSG_CHANNEL_REQUEST &&
1515 conf_get_int(ssh->conf, CONF_logomitpass)) {
1517 * If this is an X forwarding request packet, blank the fake
1520 * Note that while we blank the X authentication data here, we
1521 * don't take any special action to blank the start of an X11
1522 * channel, so using MIT-MAGIC-COOKIE-1 and actually opening
1523 * an X connection without having session blanking enabled is
1524 * likely to leak your cookie into the log.
1527 ssh_pkt_getuint32(pkt);
1528 ssh_pkt_getstring(pkt, &str, &slen);
1529 if (slen == 7 && !memcmp(str, "x11-req", 0)) {
1530 ssh2_pkt_getbool(pkt);
1531 ssh2_pkt_getbool(pkt);
1532 ssh_pkt_getstring(pkt, &str, &slen);
1533 blanks[nblanks].offset = pkt->savedpos;
1534 blanks[nblanks].type = PKTLOG_BLANK;
1535 ssh_pkt_getstring(pkt, &str, &slen);
1537 blanks[nblanks].len = pkt->savedpos - blanks[nblanks].offset;
1543 log_packet(ssh->logctx, PKT_OUTGOING, pkt->data[5],
1544 ssh2_pkt_type(ssh->pkt_kctx, ssh->pkt_actx, pkt->data[5]),
1545 pkt->body, pkt->length, nblanks, blanks,
1546 &ssh->v2_outgoing_sequence,
1547 pkt->downstream_id, pkt->additional_log_text);
1550 * Undo the above adjustment of pkt->length, to put the packet
1551 * back in the state we found it.
1553 pkt->length += (pkt->body - pkt->data);
1556 static struct Packet *ssh2_rdpkt(Ssh ssh, const unsigned char **data,
1559 struct rdpkt2_state_tag *st = &ssh->rdpkt2_state;
1561 crBegin(ssh->ssh2_rdpkt_crstate);
1563 st->pktin = ssh_new_packet();
1565 st->pktin->type = 0;
1566 st->pktin->length = 0;
1568 st->cipherblk = ssh->sccipher->blksize;
1571 if (st->cipherblk < 8)
1573 st->maclen = ssh->scmac ? ssh->scmac->len : 0;
1575 if (ssh->sccipher && (ssh->sccipher->flags & SSH_CIPHER_IS_CBC) &&
1576 ssh->scmac && !ssh->scmac_etm) {
1578 * When dealing with a CBC-mode cipher, we want to avoid the
1579 * possibility of an attacker's tweaking the ciphertext stream
1580 * so as to cause us to feed the same block to the block
1581 * cipher more than once and thus leak information
1582 * (VU#958563). The way we do this is not to take any
1583 * decisions on the basis of anything we've decrypted until
1584 * we've verified it with a MAC. That includes the packet
1585 * length, so we just read data and check the MAC repeatedly,
1586 * and when the MAC passes, see if the length we've got is
1589 * This defence is unnecessary in OpenSSH ETM mode, because
1590 * the whole point of ETM mode is that the attacker can't
1591 * tweak the ciphertext stream at all without the MAC
1592 * detecting it before we decrypt anything.
1595 /* May as well allocate the whole lot now. */
1596 st->pktin->data = snewn(OUR_V2_PACKETLIMIT + st->maclen + APIEXTRA,
1599 /* Read an amount corresponding to the MAC. */
1600 for (st->i = 0; st->i < st->maclen; st->i++) {
1601 while ((*datalen) == 0)
1603 st->pktin->data[st->i] = *(*data)++;
1609 unsigned char seq[4];
1610 ssh->scmac->start(ssh->sc_mac_ctx);
1611 PUT_32BIT(seq, st->incoming_sequence);
1612 ssh->scmac->bytes(ssh->sc_mac_ctx, seq, 4);
1615 for (;;) { /* Once around this loop per cipher block. */
1616 /* Read another cipher-block's worth, and tack it onto the end. */
1617 for (st->i = 0; st->i < st->cipherblk; st->i++) {
1618 while ((*datalen) == 0)
1620 st->pktin->data[st->packetlen+st->maclen+st->i] = *(*data)++;
1623 /* Decrypt one more block (a little further back in the stream). */
1624 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
1625 st->pktin->data + st->packetlen,
1627 /* Feed that block to the MAC. */
1628 ssh->scmac->bytes(ssh->sc_mac_ctx,
1629 st->pktin->data + st->packetlen, st->cipherblk);
1630 st->packetlen += st->cipherblk;
1631 /* See if that gives us a valid packet. */
1632 if (ssh->scmac->verresult(ssh->sc_mac_ctx,
1633 st->pktin->data + st->packetlen) &&
1634 ((st->len = toint(GET_32BIT(st->pktin->data))) ==
1637 if (st->packetlen >= OUR_V2_PACKETLIMIT) {
1638 bombout(("No valid incoming packet found"));
1639 ssh_free_packet(st->pktin);
1643 st->pktin->maxlen = st->packetlen + st->maclen;
1644 st->pktin->data = sresize(st->pktin->data,
1645 st->pktin->maxlen + APIEXTRA,
1647 } else if (ssh->scmac && ssh->scmac_etm) {
1648 st->pktin->data = snewn(4 + APIEXTRA, unsigned char);
1651 * OpenSSH encrypt-then-MAC mode: the packet length is
1652 * unencrypted, unless the cipher supports length encryption.
1654 for (st->i = st->len = 0; st->i < 4; st->i++) {
1655 while ((*datalen) == 0)
1657 st->pktin->data[st->i] = *(*data)++;
1660 /* Cipher supports length decryption, so do it */
1661 if (ssh->sccipher && (ssh->sccipher->flags & SSH_CIPHER_SEPARATE_LENGTH)) {
1662 /* Keep the packet the same though, so the MAC passes */
1663 unsigned char len[4];
1664 memcpy(len, st->pktin->data, 4);
1665 ssh->sccipher->decrypt_length(ssh->sc_cipher_ctx, len, 4, st->incoming_sequence);
1666 st->len = toint(GET_32BIT(len));
1668 st->len = toint(GET_32BIT(st->pktin->data));
1672 * _Completely_ silly lengths should be stomped on before they
1673 * do us any more damage.
1675 if (st->len < 0 || st->len > OUR_V2_PACKETLIMIT ||
1676 st->len % st->cipherblk != 0) {
1677 bombout(("Incoming packet length field was garbled"));
1678 ssh_free_packet(st->pktin);
1683 * So now we can work out the total packet length.
1685 st->packetlen = st->len + 4;
1688 * Allocate memory for the rest of the packet.
1690 st->pktin->maxlen = st->packetlen + st->maclen;
1691 st->pktin->data = sresize(st->pktin->data,
1692 st->pktin->maxlen + APIEXTRA,
1696 * Read the remainder of the packet.
1698 for (st->i = 4; st->i < st->packetlen + st->maclen; st->i++) {
1699 while ((*datalen) == 0)
1701 st->pktin->data[st->i] = *(*data)++;
1709 && !ssh->scmac->verify(ssh->sc_mac_ctx, st->pktin->data,
1710 st->len + 4, st->incoming_sequence)) {
1711 bombout(("Incorrect MAC received on packet"));
1712 ssh_free_packet(st->pktin);
1716 /* Decrypt everything between the length field and the MAC. */
1718 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
1719 st->pktin->data + 4,
1722 st->pktin->data = snewn(st->cipherblk + APIEXTRA, unsigned char);
1725 * Acquire and decrypt the first block of the packet. This will
1726 * contain the length and padding details.
1728 for (st->i = st->len = 0; st->i < st->cipherblk; st->i++) {
1729 while ((*datalen) == 0)
1731 st->pktin->data[st->i] = *(*data)++;
1736 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
1737 st->pktin->data, st->cipherblk);
1740 * Now get the length figure.
1742 st->len = toint(GET_32BIT(st->pktin->data));
1745 * _Completely_ silly lengths should be stomped on before they
1746 * do us any more damage.
1748 if (st->len < 0 || st->len > OUR_V2_PACKETLIMIT ||
1749 (st->len + 4) % st->cipherblk != 0) {
1750 bombout(("Incoming packet was garbled on decryption"));
1751 ssh_free_packet(st->pktin);
1756 * So now we can work out the total packet length.
1758 st->packetlen = st->len + 4;
1761 * Allocate memory for the rest of the packet.
1763 st->pktin->maxlen = st->packetlen + st->maclen;
1764 st->pktin->data = sresize(st->pktin->data,
1765 st->pktin->maxlen + APIEXTRA,
1769 * Read and decrypt the remainder of the packet.
1771 for (st->i = st->cipherblk; st->i < st->packetlen + st->maclen;
1773 while ((*datalen) == 0)
1775 st->pktin->data[st->i] = *(*data)++;
1778 /* Decrypt everything _except_ the MAC. */
1780 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
1781 st->pktin->data + st->cipherblk,
1782 st->packetlen - st->cipherblk);
1788 && !ssh->scmac->verify(ssh->sc_mac_ctx, st->pktin->data,
1789 st->len + 4, st->incoming_sequence)) {
1790 bombout(("Incorrect MAC received on packet"));
1791 ssh_free_packet(st->pktin);
1795 /* Get and sanity-check the amount of random padding. */
1796 st->pad = st->pktin->data[4];
1797 if (st->pad < 4 || st->len - st->pad < 1) {
1798 bombout(("Invalid padding length on received packet"));
1799 ssh_free_packet(st->pktin);
1803 * This enables us to deduce the payload length.
1805 st->payload = st->len - st->pad - 1;
1807 st->pktin->length = st->payload + 5;
1808 st->pktin->encrypted_len = st->packetlen;
1810 st->pktin->sequence = st->incoming_sequence++;
1812 st->pktin->length = st->packetlen - st->pad;
1813 assert(st->pktin->length >= 0);
1816 * Decompress packet payload.
1819 unsigned char *newpayload;
1822 ssh->sccomp->decompress(ssh->sc_comp_ctx,
1823 st->pktin->data + 5, st->pktin->length - 5,
1824 &newpayload, &newlen)) {
1825 if (st->pktin->maxlen < newlen + 5) {
1826 st->pktin->maxlen = newlen + 5;
1827 st->pktin->data = sresize(st->pktin->data,
1828 st->pktin->maxlen + APIEXTRA,
1831 st->pktin->length = 5 + newlen;
1832 memcpy(st->pktin->data + 5, newpayload, newlen);
1838 * pktin->body and pktin->length should identify the semantic
1839 * content of the packet, excluding the initial type byte.
1841 st->pktin->type = st->pktin->data[5];
1842 st->pktin->body = st->pktin->data + 6;
1843 st->pktin->length -= 6;
1844 assert(st->pktin->length >= 0); /* one last double-check */
1847 ssh2_log_incoming_packet(ssh, st->pktin);
1849 st->pktin->savedpos = 0;
1851 crFinish(st->pktin);
1854 static struct Packet *ssh2_bare_connection_rdpkt(Ssh ssh,
1855 const unsigned char **data,
1858 struct rdpkt2_bare_state_tag *st = &ssh->rdpkt2_bare_state;
1860 crBegin(ssh->ssh2_bare_rdpkt_crstate);
1863 * Read the packet length field.
1865 for (st->i = 0; st->i < 4; st->i++) {
1866 while ((*datalen) == 0)
1868 st->length[st->i] = *(*data)++;
1872 st->packetlen = toint(GET_32BIT_MSB_FIRST(st->length));
1873 if (st->packetlen <= 0 || st->packetlen >= OUR_V2_PACKETLIMIT) {
1874 bombout(("Invalid packet length received"));
1878 st->pktin = ssh_new_packet();
1879 st->pktin->data = snewn(st->packetlen, unsigned char);
1881 st->pktin->encrypted_len = st->packetlen;
1883 st->pktin->sequence = st->incoming_sequence++;
1886 * Read the remainder of the packet.
1888 for (st->i = 0; st->i < st->packetlen; st->i++) {
1889 while ((*datalen) == 0)
1891 st->pktin->data[st->i] = *(*data)++;
1896 * pktin->body and pktin->length should identify the semantic
1897 * content of the packet, excluding the initial type byte.
1899 st->pktin->type = st->pktin->data[0];
1900 st->pktin->body = st->pktin->data + 1;
1901 st->pktin->length = st->packetlen - 1;
1904 * Log incoming packet, possibly omitting sensitive fields.
1907 ssh2_log_incoming_packet(ssh, st->pktin);
1909 st->pktin->savedpos = 0;
1911 crFinish(st->pktin);
1914 static int s_wrpkt_prepare(Ssh ssh, struct Packet *pkt, int *offset_p)
1916 int pad, biglen, i, pktoffs;
1920 * XXX various versions of SC (including 8.8.4) screw up the
1921 * register allocation in this function and use the same register
1922 * (D6) for len and as a temporary, with predictable results. The
1923 * following sledgehammer prevents this.
1930 ssh1_log_outgoing_packet(ssh, pkt);
1932 if (ssh->v1_compressing) {
1933 unsigned char *compblk;
1935 zlib_compress_block(ssh->cs_comp_ctx,
1936 pkt->data + 12, pkt->length - 12,
1937 &compblk, &complen);
1938 ssh_pkt_ensure(pkt, complen + 2); /* just in case it's got bigger */
1939 memcpy(pkt->data + 12, compblk, complen);
1941 pkt->length = complen + 12;
1944 ssh_pkt_ensure(pkt, pkt->length + 4); /* space for CRC */
1946 len = pkt->length - 4 - 8; /* len(type+data+CRC) */
1947 pad = 8 - (len % 8);
1949 biglen = len + pad; /* len(padding+type+data+CRC) */
1951 for (i = pktoffs; i < 4+8; i++)
1952 pkt->data[i] = random_byte();
1953 crc = crc32_compute(pkt->data + pktoffs + 4, biglen - 4); /* all ex len */
1954 PUT_32BIT(pkt->data + pktoffs + 4 + biglen - 4, crc);
1955 PUT_32BIT(pkt->data + pktoffs, len);
1958 ssh->cipher->encrypt(ssh->v1_cipher_ctx,
1959 pkt->data + pktoffs + 4, biglen);
1961 if (offset_p) *offset_p = pktoffs;
1962 return biglen + 4; /* len(length+padding+type+data+CRC) */
1965 static int s_write(Ssh ssh, void *data, int len)
1968 log_packet(ssh->logctx, PKT_OUTGOING, -1, NULL, data, len,
1969 0, NULL, NULL, 0, NULL);
1972 return sk_write(ssh->s, (char *)data, len);
1975 static void s_wrpkt(Ssh ssh, struct Packet *pkt)
1977 int len, backlog, offset;
1978 len = s_wrpkt_prepare(ssh, pkt, &offset);
1979 backlog = s_write(ssh, pkt->data + offset, len);
1980 if (backlog > SSH_MAX_BACKLOG)
1981 ssh_throttle_all(ssh, 1, backlog);
1982 ssh_free_packet(pkt);
1985 static void s_wrpkt_defer(Ssh ssh, struct Packet *pkt)
1988 len = s_wrpkt_prepare(ssh, pkt, &offset);
1989 if (ssh->deferred_len + len > ssh->deferred_size) {
1990 ssh->deferred_size = ssh->deferred_len + len + 128;
1991 ssh->deferred_send_data = sresize(ssh->deferred_send_data,
1995 memcpy(ssh->deferred_send_data + ssh->deferred_len,
1996 pkt->data + offset, len);
1997 ssh->deferred_len += len;
1998 ssh_free_packet(pkt);
2002 * Construct a SSH-1 packet with the specified contents.
2003 * (This all-at-once interface used to be the only one, but now SSH-1
2004 * packets can also be constructed incrementally.)
2006 static struct Packet *construct_packet(Ssh ssh, int pkttype, va_list ap)
2012 pkt = ssh1_pkt_init(pkttype);
2014 while ((argtype = va_arg(ap, int)) != PKT_END) {
2015 unsigned char *argp, argchar;
2017 unsigned long argint;
2020 /* Actual fields in the packet */
2022 argint = va_arg(ap, int);
2023 ssh_pkt_adduint32(pkt, argint);
2026 argchar = (unsigned char) va_arg(ap, int);
2027 ssh_pkt_addbyte(pkt, argchar);
2030 argp = va_arg(ap, unsigned char *);
2031 arglen = va_arg(ap, int);
2032 ssh_pkt_adddata(pkt, argp, arglen);
2035 sargp = va_arg(ap, char *);
2036 ssh_pkt_addstring(pkt, sargp);
2039 bn = va_arg(ap, Bignum);
2040 ssh1_pkt_addmp(pkt, bn);
2048 static void send_packet(Ssh ssh, int pkttype, ...)
2052 va_start(ap, pkttype);
2053 pkt = construct_packet(ssh, pkttype, ap);
2058 static void defer_packet(Ssh ssh, int pkttype, ...)
2062 va_start(ap, pkttype);
2063 pkt = construct_packet(ssh, pkttype, ap);
2065 s_wrpkt_defer(ssh, pkt);
2068 static int ssh_versioncmp(const char *a, const char *b)
2071 unsigned long av, bv;
2073 av = strtoul(a, &ae, 10);
2074 bv = strtoul(b, &be, 10);
2076 return (av < bv ? -1 : +1);
2081 av = strtoul(ae, &ae, 10);
2082 bv = strtoul(be, &be, 10);
2084 return (av < bv ? -1 : +1);
2089 * Utility routines for putting an SSH-protocol `string' and
2090 * `uint32' into a hash state.
2092 static void hash_string(const struct ssh_hash *h, void *s, void *str, int len)
2094 unsigned char lenblk[4];
2095 PUT_32BIT(lenblk, len);
2096 h->bytes(s, lenblk, 4);
2097 h->bytes(s, str, len);
2100 static void hash_uint32(const struct ssh_hash *h, void *s, unsigned i)
2102 unsigned char intblk[4];
2103 PUT_32BIT(intblk, i);
2104 h->bytes(s, intblk, 4);
2108 * Packet construction functions. Mostly shared between SSH-1 and SSH-2.
2110 static void ssh_pkt_ensure(struct Packet *pkt, int length)
2112 if (pkt->maxlen < length) {
2113 unsigned char *body = pkt->body;
2114 int offset = body ? body - pkt->data : 0;
2115 pkt->maxlen = length + 256;
2116 pkt->data = sresize(pkt->data, pkt->maxlen + APIEXTRA, unsigned char);
2117 if (body) pkt->body = pkt->data + offset;
2120 static void ssh_pkt_adddata(struct Packet *pkt, const void *data, int len)
2123 ssh_pkt_ensure(pkt, pkt->length);
2124 memcpy(pkt->data + pkt->length - len, data, len);
2126 static void ssh_pkt_addbyte(struct Packet *pkt, unsigned char byte)
2128 ssh_pkt_adddata(pkt, &byte, 1);
2130 static void ssh2_pkt_addbool(struct Packet *pkt, unsigned char value)
2132 ssh_pkt_adddata(pkt, &value, 1);
2134 static void ssh_pkt_adduint32(struct Packet *pkt, unsigned long value)
2137 PUT_32BIT(x, value);
2138 ssh_pkt_adddata(pkt, x, 4);
2140 static void ssh_pkt_addstring_start(struct Packet *pkt)
2142 ssh_pkt_adduint32(pkt, 0);
2143 pkt->savedpos = pkt->length;
2145 static void ssh_pkt_addstring_data(struct Packet *pkt, const char *data,
2148 ssh_pkt_adddata(pkt, data, len);
2149 PUT_32BIT(pkt->data + pkt->savedpos - 4, pkt->length - pkt->savedpos);
2151 static void ssh_pkt_addstring_str(struct Packet *pkt, const char *data)
2153 ssh_pkt_addstring_data(pkt, data, strlen(data));
2155 static void ssh_pkt_addstring(struct Packet *pkt, const char *data)
2157 ssh_pkt_addstring_start(pkt);
2158 ssh_pkt_addstring_str(pkt, data);
2160 static void ssh1_pkt_addmp(struct Packet *pkt, Bignum b)
2162 int len = ssh1_bignum_length(b);
2163 unsigned char *data = snewn(len, unsigned char);
2164 (void) ssh1_write_bignum(data, b);
2165 ssh_pkt_adddata(pkt, data, len);
2168 static unsigned char *ssh2_mpint_fmt(Bignum b, int *len)
2171 int i, n = (bignum_bitcount(b) + 7) / 8;
2172 p = snewn(n + 1, unsigned char);
2174 for (i = 1; i <= n; i++)
2175 p[i] = bignum_byte(b, n - i);
2177 while (i <= n && p[i] == 0 && (p[i + 1] & 0x80) == 0)
2179 memmove(p, p + i, n + 1 - i);
2183 static void ssh2_pkt_addmp(struct Packet *pkt, Bignum b)
2187 p = ssh2_mpint_fmt(b, &len);
2188 ssh_pkt_addstring_start(pkt);
2189 ssh_pkt_addstring_data(pkt, (char *)p, len);
2193 static struct Packet *ssh1_pkt_init(int pkt_type)
2195 struct Packet *pkt = ssh_new_packet();
2196 pkt->length = 4 + 8; /* space for length + max padding */
2197 ssh_pkt_addbyte(pkt, pkt_type);
2198 pkt->body = pkt->data + pkt->length;
2199 pkt->type = pkt_type;
2200 pkt->downstream_id = 0;
2201 pkt->additional_log_text = NULL;
2205 /* For legacy code (SSH-1 and -2 packet construction used to be separate) */
2206 #define ssh2_pkt_ensure(pkt, length) ssh_pkt_ensure(pkt, length)
2207 #define ssh2_pkt_adddata(pkt, data, len) ssh_pkt_adddata(pkt, data, len)
2208 #define ssh2_pkt_addbyte(pkt, byte) ssh_pkt_addbyte(pkt, byte)
2209 #define ssh2_pkt_adduint32(pkt, value) ssh_pkt_adduint32(pkt, value)
2210 #define ssh2_pkt_addstring_start(pkt) ssh_pkt_addstring_start(pkt)
2211 #define ssh2_pkt_addstring_str(pkt, data) ssh_pkt_addstring_str(pkt, data)
2212 #define ssh2_pkt_addstring_data(pkt, data, len) ssh_pkt_addstring_data(pkt, data, len)
2213 #define ssh2_pkt_addstring(pkt, data) ssh_pkt_addstring(pkt, data)
2215 static struct Packet *ssh2_pkt_init(int pkt_type)
2217 struct Packet *pkt = ssh_new_packet();
2218 pkt->length = 5; /* space for packet length + padding length */
2220 pkt->type = pkt_type;
2221 ssh_pkt_addbyte(pkt, (unsigned char) pkt_type);
2222 pkt->body = pkt->data + pkt->length; /* after packet type */
2223 pkt->downstream_id = 0;
2224 pkt->additional_log_text = NULL;
2229 * Construct an SSH-2 final-form packet: compress it, encrypt it,
2230 * put the MAC on it. Final packet, ready to be sent, is stored in
2231 * pkt->data. Total length is returned.
2233 static int ssh2_pkt_construct(Ssh ssh, struct Packet *pkt)
2235 int cipherblk, maclen, padding, unencrypted_prefix, i;
2238 ssh2_log_outgoing_packet(ssh, pkt);
2240 if (ssh->bare_connection) {
2242 * Trivial packet construction for the bare connection
2245 PUT_32BIT(pkt->data + 1, pkt->length - 5);
2246 pkt->body = pkt->data + 1;
2247 ssh->v2_outgoing_sequence++; /* only for diagnostics, really */
2248 return pkt->length - 1;
2252 * Compress packet payload.
2255 unsigned char *newpayload;
2258 ssh->cscomp->compress(ssh->cs_comp_ctx, pkt->data + 5,
2260 &newpayload, &newlen)) {
2262 ssh2_pkt_adddata(pkt, newpayload, newlen);
2268 * Add padding. At least four bytes, and must also bring total
2269 * length (minus MAC) up to a multiple of the block size.
2270 * If pkt->forcepad is set, make sure the packet is at least that size
2273 cipherblk = ssh->cscipher ? ssh->cscipher->blksize : 8; /* block size */
2274 cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */
2276 unencrypted_prefix = (ssh->csmac && ssh->csmac_etm) ? 4 : 0;
2277 if (pkt->length + padding < pkt->forcepad)
2278 padding = pkt->forcepad - pkt->length;
2280 (cipherblk - (pkt->length - unencrypted_prefix + padding) % cipherblk)
2282 assert(padding <= 255);
2283 maclen = ssh->csmac ? ssh->csmac->len : 0;
2284 ssh2_pkt_ensure(pkt, pkt->length + padding + maclen);
2285 pkt->data[4] = padding;
2286 for (i = 0; i < padding; i++)
2287 pkt->data[pkt->length + i] = random_byte();
2288 PUT_32BIT(pkt->data, pkt->length + padding - 4);
2290 /* Encrypt length if the scheme requires it */
2291 if (ssh->cscipher && (ssh->cscipher->flags & SSH_CIPHER_SEPARATE_LENGTH)) {
2292 ssh->cscipher->encrypt_length(ssh->cs_cipher_ctx, pkt->data, 4,
2293 ssh->v2_outgoing_sequence);
2296 if (ssh->csmac && ssh->csmac_etm) {
2298 * OpenSSH-defined encrypt-then-MAC protocol.
2301 ssh->cscipher->encrypt(ssh->cs_cipher_ctx,
2302 pkt->data + 4, pkt->length + padding - 4);
2303 ssh->csmac->generate(ssh->cs_mac_ctx, pkt->data,
2304 pkt->length + padding,
2305 ssh->v2_outgoing_sequence);
2308 * SSH-2 standard protocol.
2311 ssh->csmac->generate(ssh->cs_mac_ctx, pkt->data,
2312 pkt->length + padding,
2313 ssh->v2_outgoing_sequence);
2315 ssh->cscipher->encrypt(ssh->cs_cipher_ctx,
2316 pkt->data, pkt->length + padding);
2319 ssh->v2_outgoing_sequence++; /* whether or not we MACed */
2320 pkt->encrypted_len = pkt->length + padding;
2322 /* Ready-to-send packet starts at pkt->data. We return length. */
2323 pkt->body = pkt->data;
2324 return pkt->length + padding + maclen;
2328 * Routines called from the main SSH code to send packets. There
2329 * are quite a few of these, because we have two separate
2330 * mechanisms for delaying the sending of packets:
2332 * - In order to send an IGNORE message and a password message in
2333 * a single fixed-length blob, we require the ability to
2334 * concatenate the encrypted forms of those two packets _into_ a
2335 * single blob and then pass it to our <network.h> transport
2336 * layer in one go. Hence, there's a deferment mechanism which
2337 * works after packet encryption.
2339 * - In order to avoid sending any connection-layer messages
2340 * during repeat key exchange, we have to queue up any such
2341 * outgoing messages _before_ they are encrypted (and in
2342 * particular before they're allocated sequence numbers), and
2343 * then send them once we've finished.
2345 * I call these mechanisms `defer' and `queue' respectively, so as
2346 * to distinguish them reasonably easily.
2348 * The functions send_noqueue() and defer_noqueue() free the packet
2349 * structure they are passed. Every outgoing packet goes through
2350 * precisely one of these functions in its life; packets passed to
2351 * ssh2_pkt_send() or ssh2_pkt_defer() either go straight to one of
2352 * these or get queued, and then when the queue is later emptied
2353 * the packets are all passed to defer_noqueue().
2355 * When using a CBC-mode cipher, it's necessary to ensure that an
2356 * attacker can't provide data to be encrypted using an IV that they
2357 * know. We ensure this by prefixing each packet that might contain
2358 * user data with an SSH_MSG_IGNORE. This is done using the deferral
2359 * mechanism, so in this case send_noqueue() ends up redirecting to
2360 * defer_noqueue(). If you don't like this inefficiency, don't use
2364 static void ssh2_pkt_defer_noqueue(Ssh, struct Packet *, int);
2365 static void ssh_pkt_defersend(Ssh);
2368 * Send an SSH-2 packet immediately, without queuing or deferring.
2370 static void ssh2_pkt_send_noqueue(Ssh ssh, struct Packet *pkt)
2374 if (ssh->cscipher != NULL && (ssh->cscipher->flags & SSH_CIPHER_IS_CBC)) {
2375 /* We need to send two packets, so use the deferral mechanism. */
2376 ssh2_pkt_defer_noqueue(ssh, pkt, FALSE);
2377 ssh_pkt_defersend(ssh);
2380 len = ssh2_pkt_construct(ssh, pkt);
2381 backlog = s_write(ssh, pkt->body, len);
2382 if (backlog > SSH_MAX_BACKLOG)
2383 ssh_throttle_all(ssh, 1, backlog);
2385 ssh->outgoing_data_size += pkt->encrypted_len;
2386 if (!ssh->kex_in_progress &&
2387 !ssh->bare_connection &&
2388 ssh->max_data_size != 0 &&
2389 ssh->outgoing_data_size > ssh->max_data_size)
2390 do_ssh2_transport(ssh, "too much data sent", -1, NULL);
2392 ssh_free_packet(pkt);
2396 * Defer an SSH-2 packet.
2398 static void ssh2_pkt_defer_noqueue(Ssh ssh, struct Packet *pkt, int noignore)
2401 if (ssh->cscipher != NULL && (ssh->cscipher->flags & SSH_CIPHER_IS_CBC) &&
2402 ssh->deferred_len == 0 && !noignore &&
2403 !(ssh->remote_bugs & BUG_CHOKES_ON_SSH2_IGNORE)) {
2405 * Interpose an SSH_MSG_IGNORE to ensure that user data don't
2406 * get encrypted with a known IV.
2408 struct Packet *ipkt = ssh2_pkt_init(SSH2_MSG_IGNORE);
2409 ssh2_pkt_addstring_start(ipkt);
2410 ssh2_pkt_defer_noqueue(ssh, ipkt, TRUE);
2412 len = ssh2_pkt_construct(ssh, pkt);
2413 if (ssh->deferred_len + len > ssh->deferred_size) {
2414 ssh->deferred_size = ssh->deferred_len + len + 128;
2415 ssh->deferred_send_data = sresize(ssh->deferred_send_data,
2419 memcpy(ssh->deferred_send_data + ssh->deferred_len, pkt->body, len);
2420 ssh->deferred_len += len;
2421 ssh->deferred_data_size += pkt->encrypted_len;
2422 ssh_free_packet(pkt);
2426 * Queue an SSH-2 packet.
2428 static void ssh2_pkt_queue(Ssh ssh, struct Packet *pkt)
2430 assert(ssh->queueing);
2432 if (ssh->queuelen >= ssh->queuesize) {
2433 ssh->queuesize = ssh->queuelen + 32;
2434 ssh->queue = sresize(ssh->queue, ssh->queuesize, struct Packet *);
2437 ssh->queue[ssh->queuelen++] = pkt;
2441 * Either queue or send a packet, depending on whether queueing is
2444 static void ssh2_pkt_send(Ssh ssh, struct Packet *pkt)
2447 ssh2_pkt_queue(ssh, pkt);
2449 ssh2_pkt_send_noqueue(ssh, pkt);
2453 * Either queue or defer a packet, depending on whether queueing is
2456 static void ssh2_pkt_defer(Ssh ssh, struct Packet *pkt)
2459 ssh2_pkt_queue(ssh, pkt);
2461 ssh2_pkt_defer_noqueue(ssh, pkt, FALSE);
2465 * Send the whole deferred data block constructed by
2466 * ssh2_pkt_defer() or SSH-1's defer_packet().
2468 * The expected use of the defer mechanism is that you call
2469 * ssh2_pkt_defer() a few times, then call ssh_pkt_defersend(). If
2470 * not currently queueing, this simply sets up deferred_send_data
2471 * and then sends it. If we _are_ currently queueing, the calls to
2472 * ssh2_pkt_defer() put the deferred packets on to the queue
2473 * instead, and therefore ssh_pkt_defersend() has no deferred data
2474 * to send. Hence, there's no need to make it conditional on
2477 static void ssh_pkt_defersend(Ssh ssh)
2480 backlog = s_write(ssh, ssh->deferred_send_data, ssh->deferred_len);
2481 ssh->deferred_len = ssh->deferred_size = 0;
2482 sfree(ssh->deferred_send_data);
2483 ssh->deferred_send_data = NULL;
2484 if (backlog > SSH_MAX_BACKLOG)
2485 ssh_throttle_all(ssh, 1, backlog);
2487 ssh->outgoing_data_size += ssh->deferred_data_size;
2488 if (!ssh->kex_in_progress &&
2489 !ssh->bare_connection &&
2490 ssh->max_data_size != 0 &&
2491 ssh->outgoing_data_size > ssh->max_data_size)
2492 do_ssh2_transport(ssh, "too much data sent", -1, NULL);
2493 ssh->deferred_data_size = 0;
2497 * Send a packet whose length needs to be disguised (typically
2498 * passwords or keyboard-interactive responses).
2500 static void ssh2_pkt_send_with_padding(Ssh ssh, struct Packet *pkt,
2506 * The simplest way to do this is to adjust the
2507 * variable-length padding field in the outgoing packet.
2509 * Currently compiled out, because some Cisco SSH servers
2510 * don't like excessively padded packets (bah, why's it
2513 pkt->forcepad = padsize;
2514 ssh2_pkt_send(ssh, pkt);
2519 * If we can't do that, however, an alternative approach is
2520 * to use the pkt_defer mechanism to bundle the packet
2521 * tightly together with an SSH_MSG_IGNORE such that their
2522 * combined length is a constant. So first we construct the
2523 * final form of this packet and defer its sending.
2525 ssh2_pkt_defer(ssh, pkt);
2528 * Now construct an SSH_MSG_IGNORE which includes a string
2529 * that's an exact multiple of the cipher block size. (If
2530 * the cipher is NULL so that the block size is
2531 * unavailable, we don't do this trick at all, because we
2532 * gain nothing by it.)
2534 if (ssh->cscipher &&
2535 !(ssh->remote_bugs & BUG_CHOKES_ON_SSH2_IGNORE)) {
2538 stringlen = (256 - ssh->deferred_len);
2539 stringlen += ssh->cscipher->blksize - 1;
2540 stringlen -= (stringlen % ssh->cscipher->blksize);
2543 * Temporarily disable actual compression, so we
2544 * can guarantee to get this string exactly the
2545 * length we want it. The compression-disabling
2546 * routine should return an integer indicating how
2547 * many bytes we should adjust our string length
2551 ssh->cscomp->disable_compression(ssh->cs_comp_ctx);
2553 pkt = ssh2_pkt_init(SSH2_MSG_IGNORE);
2554 ssh2_pkt_addstring_start(pkt);
2555 for (i = 0; i < stringlen; i++) {
2556 char c = (char) random_byte();
2557 ssh2_pkt_addstring_data(pkt, &c, 1);
2559 ssh2_pkt_defer(ssh, pkt);
2561 ssh_pkt_defersend(ssh);
2566 * Send all queued SSH-2 packets. We send them by means of
2567 * ssh2_pkt_defer_noqueue(), in case they included a pair of
2568 * packets that needed to be lumped together.
2570 static void ssh2_pkt_queuesend(Ssh ssh)
2574 assert(!ssh->queueing);
2576 for (i = 0; i < ssh->queuelen; i++)
2577 ssh2_pkt_defer_noqueue(ssh, ssh->queue[i], FALSE);
2580 ssh_pkt_defersend(ssh);
2584 void bndebug(char *string, Bignum b)
2588 p = ssh2_mpint_fmt(b, &len);
2589 debug(("%s", string));
2590 for (i = 0; i < len; i++)
2591 debug((" %02x", p[i]));
2597 static void hash_mpint(const struct ssh_hash *h, void *s, Bignum b)
2601 p = ssh2_mpint_fmt(b, &len);
2602 hash_string(h, s, p, len);
2607 * Packet decode functions for both SSH-1 and SSH-2.
2609 static unsigned long ssh_pkt_getuint32(struct Packet *pkt)
2611 unsigned long value;
2612 if (pkt->length - pkt->savedpos < 4)
2613 return 0; /* arrgh, no way to decline (FIXME?) */
2614 value = GET_32BIT(pkt->body + pkt->savedpos);
2618 static int ssh2_pkt_getbool(struct Packet *pkt)
2620 unsigned long value;
2621 if (pkt->length - pkt->savedpos < 1)
2622 return 0; /* arrgh, no way to decline (FIXME?) */
2623 value = pkt->body[pkt->savedpos] != 0;
2627 static void ssh_pkt_getstring(struct Packet *pkt, char **p, int *length)
2632 if (pkt->length - pkt->savedpos < 4)
2634 len = toint(GET_32BIT(pkt->body + pkt->savedpos));
2639 if (pkt->length - pkt->savedpos < *length)
2641 *p = (char *)(pkt->body + pkt->savedpos);
2642 pkt->savedpos += *length;
2644 static void *ssh_pkt_getdata(struct Packet *pkt, int length)
2646 if (pkt->length - pkt->savedpos < length)
2648 pkt->savedpos += length;
2649 return pkt->body + (pkt->savedpos - length);
2651 static int ssh1_pkt_getrsakey(struct Packet *pkt, struct RSAKey *key,
2652 const unsigned char **keystr)
2656 j = makekey(pkt->body + pkt->savedpos,
2657 pkt->length - pkt->savedpos,
2664 assert(pkt->savedpos < pkt->length);
2668 static Bignum ssh1_pkt_getmp(struct Packet *pkt)
2673 j = ssh1_read_bignum(pkt->body + pkt->savedpos,
2674 pkt->length - pkt->savedpos, &b);
2682 static Bignum ssh2_pkt_getmp(struct Packet *pkt)
2688 ssh_pkt_getstring(pkt, &p, &length);
2693 b = bignum_from_bytes((unsigned char *)p, length);
2698 * Helper function to add an SSH-2 signature blob to a packet.
2699 * Expects to be shown the public key blob as well as the signature
2700 * blob. Normally works just like ssh2_pkt_addstring, but will
2701 * fiddle with the signature packet if necessary for
2702 * BUG_SSH2_RSA_PADDING.
2704 static void ssh2_add_sigblob(Ssh ssh, struct Packet *pkt,
2705 void *pkblob_v, int pkblob_len,
2706 void *sigblob_v, int sigblob_len)
2708 unsigned char *pkblob = (unsigned char *)pkblob_v;
2709 unsigned char *sigblob = (unsigned char *)sigblob_v;
2711 /* dmemdump(pkblob, pkblob_len); */
2712 /* dmemdump(sigblob, sigblob_len); */
2715 * See if this is in fact an ssh-rsa signature and a buggy
2716 * server; otherwise we can just do this the easy way.
2718 if ((ssh->remote_bugs & BUG_SSH2_RSA_PADDING) && pkblob_len > 4+7+4 &&
2719 (GET_32BIT(pkblob) == 7 && !memcmp(pkblob+4, "ssh-rsa", 7))) {
2720 int pos, len, siglen;
2723 * Find the byte length of the modulus.
2726 pos = 4+7; /* skip over "ssh-rsa" */
2727 len = toint(GET_32BIT(pkblob+pos)); /* get length of exponent */
2728 if (len < 0 || len > pkblob_len - pos - 4)
2730 pos += 4 + len; /* skip over exponent */
2731 if (pkblob_len - pos < 4)
2733 len = toint(GET_32BIT(pkblob+pos)); /* find length of modulus */
2734 if (len < 0 || len > pkblob_len - pos - 4)
2736 pos += 4; /* find modulus itself */
2737 while (len > 0 && pkblob[pos] == 0)
2739 /* debug(("modulus length is %d\n", len)); */
2742 * Now find the signature integer.
2744 pos = 4+7; /* skip over "ssh-rsa" */
2745 if (sigblob_len < pos+4)
2747 siglen = toint(GET_32BIT(sigblob+pos));
2748 if (siglen != sigblob_len - pos - 4)
2750 /* debug(("signature length is %d\n", siglen)); */
2752 if (len != siglen) {
2753 unsigned char newlen[4];
2754 ssh2_pkt_addstring_start(pkt);
2755 ssh2_pkt_addstring_data(pkt, (char *)sigblob, pos);
2756 /* dmemdump(sigblob, pos); */
2757 pos += 4; /* point to start of actual sig */
2758 PUT_32BIT(newlen, len);
2759 ssh2_pkt_addstring_data(pkt, (char *)newlen, 4);
2760 /* dmemdump(newlen, 4); */
2762 while (len-- > siglen) {
2763 ssh2_pkt_addstring_data(pkt, (char *)newlen, 1);
2764 /* dmemdump(newlen, 1); */
2766 ssh2_pkt_addstring_data(pkt, (char *)(sigblob+pos), siglen);
2767 /* dmemdump(sigblob+pos, siglen); */
2771 /* Otherwise fall through and do it the easy way. We also come
2772 * here as a fallback if we discover above that the key blob
2773 * is misformatted in some way. */
2777 ssh2_pkt_addstring_start(pkt);
2778 ssh2_pkt_addstring_data(pkt, (char *)sigblob, sigblob_len);
2782 * Examine the remote side's version string and compare it against
2783 * a list of known buggy implementations.
2785 static void ssh_detect_bugs(Ssh ssh, char *vstring)
2787 char *imp; /* pointer to implementation part */
2789 imp += strcspn(imp, "-");
2791 imp += strcspn(imp, "-");
2794 ssh->remote_bugs = 0;
2797 * General notes on server version strings:
2798 * - Not all servers reporting "Cisco-1.25" have all the bugs listed
2799 * here -- in particular, we've heard of one that's perfectly happy
2800 * with SSH1_MSG_IGNOREs -- but this string never seems to change,
2801 * so we can't distinguish them.
2803 if (conf_get_int(ssh->conf, CONF_sshbug_ignore1) == FORCE_ON ||
2804 (conf_get_int(ssh->conf, CONF_sshbug_ignore1) == AUTO &&
2805 (!strcmp(imp, "1.2.18") || !strcmp(imp, "1.2.19") ||
2806 !strcmp(imp, "1.2.20") || !strcmp(imp, "1.2.21") ||
2807 !strcmp(imp, "1.2.22") || !strcmp(imp, "Cisco-1.25") ||
2808 !strcmp(imp, "OSU_1.4alpha3") || !strcmp(imp, "OSU_1.5alpha4")))) {
2810 * These versions don't support SSH1_MSG_IGNORE, so we have
2811 * to use a different defence against password length
2814 ssh->remote_bugs |= BUG_CHOKES_ON_SSH1_IGNORE;
2815 logevent("We believe remote version has SSH-1 ignore bug");
2818 if (conf_get_int(ssh->conf, CONF_sshbug_plainpw1) == FORCE_ON ||
2819 (conf_get_int(ssh->conf, CONF_sshbug_plainpw1) == AUTO &&
2820 (!strcmp(imp, "Cisco-1.25") || !strcmp(imp, "OSU_1.4alpha3")))) {
2822 * These versions need a plain password sent; they can't
2823 * handle having a null and a random length of data after
2826 ssh->remote_bugs |= BUG_NEEDS_SSH1_PLAIN_PASSWORD;
2827 logevent("We believe remote version needs a plain SSH-1 password");
2830 if (conf_get_int(ssh->conf, CONF_sshbug_rsa1) == FORCE_ON ||
2831 (conf_get_int(ssh->conf, CONF_sshbug_rsa1) == AUTO &&
2832 (!strcmp(imp, "Cisco-1.25")))) {
2834 * These versions apparently have no clue whatever about
2835 * RSA authentication and will panic and die if they see
2836 * an AUTH_RSA message.
2838 ssh->remote_bugs |= BUG_CHOKES_ON_RSA;
2839 logevent("We believe remote version can't handle SSH-1 RSA authentication");
2842 if (conf_get_int(ssh->conf, CONF_sshbug_hmac2) == FORCE_ON ||
2843 (conf_get_int(ssh->conf, CONF_sshbug_hmac2) == AUTO &&
2844 !wc_match("* VShell", imp) &&
2845 (wc_match("2.1.0*", imp) || wc_match("2.0.*", imp) ||
2846 wc_match("2.2.0*", imp) || wc_match("2.3.0*", imp) ||
2847 wc_match("2.1 *", imp)))) {
2849 * These versions have the HMAC bug.
2851 ssh->remote_bugs |= BUG_SSH2_HMAC;
2852 logevent("We believe remote version has SSH-2 HMAC bug");
2855 if (conf_get_int(ssh->conf, CONF_sshbug_derivekey2) == FORCE_ON ||
2856 (conf_get_int(ssh->conf, CONF_sshbug_derivekey2) == AUTO &&
2857 !wc_match("* VShell", imp) &&
2858 (wc_match("2.0.0*", imp) || wc_match("2.0.10*", imp) ))) {
2860 * These versions have the key-derivation bug (failing to
2861 * include the literal shared secret in the hashes that
2862 * generate the keys).
2864 ssh->remote_bugs |= BUG_SSH2_DERIVEKEY;
2865 logevent("We believe remote version has SSH-2 key-derivation bug");
2868 if (conf_get_int(ssh->conf, CONF_sshbug_rsapad2) == FORCE_ON ||
2869 (conf_get_int(ssh->conf, CONF_sshbug_rsapad2) == AUTO &&
2870 (wc_match("OpenSSH_2.[5-9]*", imp) ||
2871 wc_match("OpenSSH_3.[0-2]*", imp) ||
2872 wc_match("mod_sftp/0.[0-8]*", imp) ||
2873 wc_match("mod_sftp/0.9.[0-8]", imp)))) {
2875 * These versions have the SSH-2 RSA padding bug.
2877 ssh->remote_bugs |= BUG_SSH2_RSA_PADDING;
2878 logevent("We believe remote version has SSH-2 RSA padding bug");
2881 if (conf_get_int(ssh->conf, CONF_sshbug_pksessid2) == FORCE_ON ||
2882 (conf_get_int(ssh->conf, CONF_sshbug_pksessid2) == AUTO &&
2883 wc_match("OpenSSH_2.[0-2]*", imp))) {
2885 * These versions have the SSH-2 session-ID bug in
2886 * public-key authentication.
2888 ssh->remote_bugs |= BUG_SSH2_PK_SESSIONID;
2889 logevent("We believe remote version has SSH-2 public-key-session-ID bug");
2892 if (conf_get_int(ssh->conf, CONF_sshbug_rekey2) == FORCE_ON ||
2893 (conf_get_int(ssh->conf, CONF_sshbug_rekey2) == AUTO &&
2894 (wc_match("DigiSSH_2.0", imp) ||
2895 wc_match("OpenSSH_2.[0-4]*", imp) ||
2896 wc_match("OpenSSH_2.5.[0-3]*", imp) ||
2897 wc_match("Sun_SSH_1.0", imp) ||
2898 wc_match("Sun_SSH_1.0.1", imp) ||
2899 /* All versions <= 1.2.6 (they changed their format in 1.2.7) */
2900 wc_match("WeOnlyDo-*", imp)))) {
2902 * These versions have the SSH-2 rekey bug.
2904 ssh->remote_bugs |= BUG_SSH2_REKEY;
2905 logevent("We believe remote version has SSH-2 rekey bug");
2908 if (conf_get_int(ssh->conf, CONF_sshbug_maxpkt2) == FORCE_ON ||
2909 (conf_get_int(ssh->conf, CONF_sshbug_maxpkt2) == AUTO &&
2910 (wc_match("1.36_sshlib GlobalSCAPE", imp) ||
2911 wc_match("1.36 sshlib: GlobalScape", imp)))) {
2913 * This version ignores our makpkt and needs to be throttled.
2915 ssh->remote_bugs |= BUG_SSH2_MAXPKT;
2916 logevent("We believe remote version ignores SSH-2 maximum packet size");
2919 if (conf_get_int(ssh->conf, CONF_sshbug_ignore2) == FORCE_ON) {
2921 * Servers that don't support SSH2_MSG_IGNORE. Currently,
2922 * none detected automatically.
2924 ssh->remote_bugs |= BUG_CHOKES_ON_SSH2_IGNORE;
2925 logevent("We believe remote version has SSH-2 ignore bug");
2928 if (conf_get_int(ssh->conf, CONF_sshbug_oldgex2) == FORCE_ON ||
2929 (conf_get_int(ssh->conf, CONF_sshbug_oldgex2) == AUTO &&
2930 (wc_match("OpenSSH_2.[235]*", imp)))) {
2932 * These versions only support the original (pre-RFC4419)
2933 * SSH-2 GEX request, and disconnect with a protocol error if
2934 * we use the newer version.
2936 ssh->remote_bugs |= BUG_SSH2_OLDGEX;
2937 logevent("We believe remote version has outdated SSH-2 GEX");
2940 if (conf_get_int(ssh->conf, CONF_sshbug_winadj) == FORCE_ON) {
2942 * Servers that don't support our winadj request for one
2943 * reason or another. Currently, none detected automatically.
2945 ssh->remote_bugs |= BUG_CHOKES_ON_WINADJ;
2946 logevent("We believe remote version has winadj bug");
2949 if (conf_get_int(ssh->conf, CONF_sshbug_chanreq) == FORCE_ON ||
2950 (conf_get_int(ssh->conf, CONF_sshbug_chanreq) == AUTO &&
2951 (wc_match("OpenSSH_[2-5].*", imp) ||
2952 wc_match("OpenSSH_6.[0-6]*", imp) ||
2953 wc_match("dropbear_0.[2-4][0-9]*", imp) ||
2954 wc_match("dropbear_0.5[01]*", imp)))) {
2956 * These versions have the SSH-2 channel request bug.
2957 * OpenSSH 6.7 and above do not:
2958 * https://bugzilla.mindrot.org/show_bug.cgi?id=1818
2959 * dropbear_0.52 and above do not:
2960 * https://secure.ucc.asn.au/hg/dropbear/rev/cd02449b709c
2962 ssh->remote_bugs |= BUG_SENDS_LATE_REQUEST_REPLY;
2963 logevent("We believe remote version has SSH-2 channel request bug");
2968 * The `software version' part of an SSH version string is required
2969 * to contain no spaces or minus signs.
2971 static void ssh_fix_verstring(char *str)
2973 /* Eat "<protoversion>-". */
2974 while (*str && *str != '-') str++;
2975 assert(*str == '-'); str++;
2977 /* Convert minus signs and spaces in the remaining string into
2980 if (*str == '-' || *str == ' ')
2987 * Send an appropriate SSH version string.
2989 static void ssh_send_verstring(Ssh ssh, const char *protoname, char *svers)
2993 if (ssh->version == 2) {
2995 * Construct a v2 version string.
2997 verstring = dupprintf("%s2.0-%s\015\012", protoname, sshver);
3000 * Construct a v1 version string.
3002 assert(!strcmp(protoname, "SSH-")); /* no v1 bare connection protocol */
3003 verstring = dupprintf("SSH-%s-%s\012",
3004 (ssh_versioncmp(svers, "1.5") <= 0 ?
3009 ssh_fix_verstring(verstring + strlen(protoname));
3011 if (ssh->version == 2) {
3014 * Record our version string.
3016 len = strcspn(verstring, "\015\012");
3017 ssh->v_c = snewn(len + 1, char);
3018 memcpy(ssh->v_c, verstring, len);
3022 logeventf(ssh, "We claim version: %.*s",
3023 strcspn(verstring, "\015\012"), verstring);
3024 s_write(ssh, verstring, strlen(verstring));
3028 static int do_ssh_init(Ssh ssh, unsigned char c)
3030 static const char protoname[] = "SSH-";
3032 struct do_ssh_init_state {
3041 crState(do_ssh_init_state);
3045 /* Search for a line beginning with the protocol name prefix in
3048 for (s->i = 0; protoname[s->i]; s->i++) {
3049 if ((char)c != protoname[s->i]) goto no;
3059 s->vstrsize = sizeof(protoname) + 16;
3060 s->vstring = snewn(s->vstrsize, char);
3061 strcpy(s->vstring, protoname);
3062 s->vslen = strlen(protoname);
3065 if (s->vslen >= s->vstrsize - 1) {
3067 s->vstring = sresize(s->vstring, s->vstrsize, char);
3069 s->vstring[s->vslen++] = c;
3072 s->version[s->i] = '\0';
3074 } else if (s->i < sizeof(s->version) - 1)
3075 s->version[s->i++] = c;
3076 } else if (c == '\012')
3078 crReturn(1); /* get another char */
3081 ssh->agentfwd_enabled = FALSE;
3082 ssh->rdpkt2_state.incoming_sequence = 0;
3084 s->vstring[s->vslen] = 0;
3085 s->vstring[strcspn(s->vstring, "\015\012")] = '\0';/* remove EOL chars */
3086 logeventf(ssh, "Server version: %s", s->vstring);
3087 ssh_detect_bugs(ssh, s->vstring);
3090 * Decide which SSH protocol version to support.
3093 /* Anything strictly below "2.0" means protocol 1 is supported. */
3094 s->proto1 = ssh_versioncmp(s->version, "2.0") < 0;
3095 /* Anything greater or equal to "1.99" means protocol 2 is supported. */
3096 s->proto2 = ssh_versioncmp(s->version, "1.99") >= 0;
3098 if (conf_get_int(ssh->conf, CONF_sshprot) == 0 && !s->proto1) {
3099 bombout(("SSH protocol version 1 required by configuration but "
3100 "not provided by server"));
3103 if (conf_get_int(ssh->conf, CONF_sshprot) == 3 && !s->proto2) {
3104 bombout(("SSH protocol version 2 required by configuration but "
3105 "not provided by server"));
3109 if (s->proto2 && (conf_get_int(ssh->conf, CONF_sshprot) >= 2 || !s->proto1))
3114 logeventf(ssh, "Using SSH protocol version %d", ssh->version);
3116 /* Send the version string, if we haven't already */
3117 if (conf_get_int(ssh->conf, CONF_sshprot) != 3)
3118 ssh_send_verstring(ssh, protoname, s->version);
3120 if (ssh->version == 2) {
3123 * Record their version string.
3125 len = strcspn(s->vstring, "\015\012");
3126 ssh->v_s = snewn(len + 1, char);
3127 memcpy(ssh->v_s, s->vstring, len);
3131 * Initialise SSH-2 protocol.
3133 ssh->protocol = ssh2_protocol;
3134 ssh2_protocol_setup(ssh);
3135 ssh->s_rdpkt = ssh2_rdpkt;
3138 * Initialise SSH-1 protocol.
3140 ssh->protocol = ssh1_protocol;
3141 ssh1_protocol_setup(ssh);
3142 ssh->s_rdpkt = ssh1_rdpkt;
3144 if (ssh->version == 2)
3145 do_ssh2_transport(ssh, NULL, -1, NULL);
3147 update_specials_menu(ssh->frontend);
3148 ssh->state = SSH_STATE_BEFORE_SIZE;
3149 ssh->pinger = pinger_new(ssh->conf, &ssh_backend, ssh);
3156 static int do_ssh_connection_init(Ssh ssh, unsigned char c)
3159 * Ordinary SSH begins with the banner "SSH-x.y-...". This is just
3160 * the ssh-connection part, extracted and given a trivial binary
3161 * packet protocol, so we replace 'SSH-' at the start with a new
3162 * name. In proper SSH style (though of course this part of the
3163 * proper SSH protocol _isn't_ subject to this kind of
3164 * DNS-domain-based extension), we define the new name in our
3167 static const char protoname[] =
3168 "SSHCONNECTION@putty.projects.tartarus.org-";
3170 struct do_ssh_connection_init_state {
3178 crState(do_ssh_connection_init_state);
3182 /* Search for a line beginning with the protocol name prefix in
3185 for (s->i = 0; protoname[s->i]; s->i++) {
3186 if ((char)c != protoname[s->i]) goto no;
3196 s->vstrsize = sizeof(protoname) + 16;
3197 s->vstring = snewn(s->vstrsize, char);
3198 strcpy(s->vstring, protoname);
3199 s->vslen = strlen(protoname);
3202 if (s->vslen >= s->vstrsize - 1) {
3204 s->vstring = sresize(s->vstring, s->vstrsize, char);
3206 s->vstring[s->vslen++] = c;
3209 s->version[s->i] = '\0';
3211 } else if (s->i < sizeof(s->version) - 1)
3212 s->version[s->i++] = c;
3213 } else if (c == '\012')
3215 crReturn(1); /* get another char */
3218 ssh->agentfwd_enabled = FALSE;
3219 ssh->rdpkt2_bare_state.incoming_sequence = 0;
3221 s->vstring[s->vslen] = 0;
3222 s->vstring[strcspn(s->vstring, "\015\012")] = '\0';/* remove EOL chars */
3223 logeventf(ssh, "Server version: %s", s->vstring);
3224 ssh_detect_bugs(ssh, s->vstring);
3227 * Decide which SSH protocol version to support. This is easy in
3228 * bare ssh-connection mode: only 2.0 is legal.
3230 if (ssh_versioncmp(s->version, "2.0") < 0) {
3231 bombout(("Server announces compatibility with SSH-1 in bare ssh-connection protocol"));
3234 if (conf_get_int(ssh->conf, CONF_sshprot) == 0) {
3235 bombout(("Bare ssh-connection protocol cannot be run in SSH-1-only mode"));
3241 logeventf(ssh, "Using bare ssh-connection protocol");
3243 /* Send the version string, if we haven't already */
3244 ssh_send_verstring(ssh, protoname, s->version);
3247 * Initialise bare connection protocol.
3249 ssh->protocol = ssh2_bare_connection_protocol;
3250 ssh2_bare_connection_protocol_setup(ssh);
3251 ssh->s_rdpkt = ssh2_bare_connection_rdpkt;
3253 update_specials_menu(ssh->frontend);
3254 ssh->state = SSH_STATE_BEFORE_SIZE;
3255 ssh->pinger = pinger_new(ssh->conf, &ssh_backend, ssh);
3258 * Get authconn (really just conn) under way.
3260 do_ssh2_authconn(ssh, NULL, 0, NULL);
3267 static void ssh_process_incoming_data(Ssh ssh,
3268 const unsigned char **data, int *datalen)
3270 struct Packet *pktin;
3272 pktin = ssh->s_rdpkt(ssh, data, datalen);
3274 ssh->protocol(ssh, NULL, 0, pktin);
3275 ssh_free_packet(pktin);
3279 static void ssh_queue_incoming_data(Ssh ssh,
3280 const unsigned char **data, int *datalen)
3282 bufchain_add(&ssh->queued_incoming_data, *data, *datalen);
3287 static void ssh_process_queued_incoming_data(Ssh ssh)
3290 const unsigned char *data;
3293 while (!ssh->frozen && bufchain_size(&ssh->queued_incoming_data)) {
3294 bufchain_prefix(&ssh->queued_incoming_data, &vdata, &len);
3298 while (!ssh->frozen && len > 0)
3299 ssh_process_incoming_data(ssh, &data, &len);
3302 bufchain_consume(&ssh->queued_incoming_data, origlen - len);
3306 static void ssh_set_frozen(Ssh ssh, int frozen)
3309 sk_set_frozen(ssh->s, frozen);
3310 ssh->frozen = frozen;
3313 static void ssh_gotdata(Ssh ssh, const unsigned char *data, int datalen)
3315 /* Log raw data, if we're in that mode. */
3317 log_packet(ssh->logctx, PKT_INCOMING, -1, NULL, data, datalen,
3318 0, NULL, NULL, 0, NULL);
3320 crBegin(ssh->ssh_gotdata_crstate);
3323 * To begin with, feed the characters one by one to the
3324 * protocol initialisation / selection function do_ssh_init().
3325 * When that returns 0, we're done with the initial greeting
3326 * exchange and can move on to packet discipline.
3329 int ret; /* need not be kept across crReturn */
3331 crReturnV; /* more data please */
3332 ret = ssh->do_ssh_init(ssh, *data);
3340 * We emerge from that loop when the initial negotiation is
3341 * over and we have selected an s_rdpkt function. Now pass
3342 * everything to s_rdpkt, and then pass the resulting packets
3343 * to the proper protocol handler.
3347 while (bufchain_size(&ssh->queued_incoming_data) > 0 || datalen > 0) {
3349 ssh_queue_incoming_data(ssh, &data, &datalen);
3350 /* This uses up all data and cannot cause anything interesting
3351 * to happen; indeed, for anything to happen at all, we must
3352 * return, so break out. */
3354 } else if (bufchain_size(&ssh->queued_incoming_data) > 0) {
3355 /* This uses up some or all data, and may freeze the
3357 ssh_process_queued_incoming_data(ssh);
3359 /* This uses up some or all data, and may freeze the
3361 ssh_process_incoming_data(ssh, &data, &datalen);
3363 /* FIXME this is probably EBW. */
3364 if (ssh->state == SSH_STATE_CLOSED)
3367 /* We're out of data. Go and get some more. */
3373 static int ssh_do_close(Ssh ssh, int notify_exit)
3376 struct ssh_channel *c;
3378 ssh->state = SSH_STATE_CLOSED;
3379 expire_timer_context(ssh);
3384 notify_remote_exit(ssh->frontend);
3389 * Now we must shut down any port- and X-forwarded channels going
3390 * through this connection.
3392 if (ssh->channels) {
3393 while (NULL != (c = index234(ssh->channels, 0))) {
3396 x11_close(c->u.x11.xconn);
3399 case CHAN_SOCKDATA_DORMANT:
3400 pfd_close(c->u.pfd.pf);
3403 del234(ssh->channels, c); /* moving next one to index 0 */
3404 if (ssh->version == 2)
3405 bufchain_clear(&c->v.v2.outbuffer);
3410 * Go through port-forwardings, and close any associated
3411 * listening sockets.
3413 if (ssh->portfwds) {
3414 struct ssh_portfwd *pf;
3415 while (NULL != (pf = index234(ssh->portfwds, 0))) {
3416 /* Dispose of any listening socket. */
3418 pfl_terminate(pf->local);
3419 del234(ssh->portfwds, pf); /* moving next one to index 0 */
3422 freetree234(ssh->portfwds);
3423 ssh->portfwds = NULL;
3427 * Also stop attempting to connection-share.
3429 if (ssh->connshare) {
3430 sharestate_free(ssh->connshare);
3431 ssh->connshare = NULL;
3437 static void ssh_socket_log(Plug plug, int type, SockAddr addr, int port,
3438 const char *error_msg, int error_code)
3440 Ssh ssh = (Ssh) plug;
3441 char addrbuf[256], *msg;
3443 if (ssh->attempting_connshare) {
3445 * While we're attempting connection sharing, don't loudly log
3446 * everything that happens. Real TCP connections need to be
3447 * logged when we _start_ trying to connect, because it might
3448 * be ages before they respond if something goes wrong; but
3449 * connection sharing is local and quick to respond, and it's
3450 * sufficient to simply wait and see whether it worked
3454 sk_getaddr(addr, addrbuf, lenof(addrbuf));
3457 if (sk_addr_needs_port(addr)) {
3458 msg = dupprintf("Connecting to %s port %d", addrbuf, port);
3460 msg = dupprintf("Connecting to %s", addrbuf);
3463 msg = dupprintf("Failed to connect to %s: %s", addrbuf, error_msg);
3471 void ssh_connshare_log(Ssh ssh, int event, const char *logtext,
3472 const char *ds_err, const char *us_err)
3474 if (event == SHARE_NONE) {
3475 /* In this case, 'logtext' is an error message indicating a
3476 * reason why connection sharing couldn't be set up _at all_.
3477 * Failing that, ds_err and us_err indicate why we couldn't be
3478 * a downstream and an upstream respectively. */
3480 logeventf(ssh, "Could not set up connection sharing: %s", logtext);
3483 logeventf(ssh, "Could not set up connection sharing"
3484 " as downstream: %s", ds_err);
3486 logeventf(ssh, "Could not set up connection sharing"
3487 " as upstream: %s", us_err);
3489 } else if (event == SHARE_DOWNSTREAM) {
3490 /* In this case, 'logtext' is a local endpoint address */
3491 logeventf(ssh, "Using existing shared connection at %s", logtext);
3492 /* Also we should mention this in the console window to avoid
3493 * confusing users as to why this window doesn't behave the
3495 if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
3496 c_write_str(ssh,"Reusing a shared connection to this server.\r\n");
3498 } else if (event == SHARE_UPSTREAM) {
3499 /* In this case, 'logtext' is a local endpoint address too */
3500 logeventf(ssh, "Sharing this connection at %s", logtext);
3504 static int ssh_closing(Plug plug, const char *error_msg, int error_code,
3507 Ssh ssh = (Ssh) plug;
3508 int need_notify = ssh_do_close(ssh, FALSE);
3511 if (!ssh->close_expected)
3512 error_msg = "Server unexpectedly closed network connection";
3514 error_msg = "Server closed network connection";
3517 if (ssh->close_expected && ssh->clean_exit && ssh->exitcode < 0)
3521 notify_remote_exit(ssh->frontend);
3524 logevent(error_msg);
3525 if (!ssh->close_expected || !ssh->clean_exit)
3526 connection_fatal(ssh->frontend, "%s", error_msg);
3530 static int ssh_receive(Plug plug, int urgent, char *data, int len)
3532 Ssh ssh = (Ssh) plug;
3533 ssh_gotdata(ssh, (unsigned char *)data, len);
3534 if (ssh->state == SSH_STATE_CLOSED) {
3535 ssh_do_close(ssh, TRUE);
3541 static void ssh_sent(Plug plug, int bufsize)
3543 Ssh ssh = (Ssh) plug;
3545 * If the send backlog on the SSH socket itself clears, we
3546 * should unthrottle the whole world if it was throttled.
3548 if (bufsize < SSH_MAX_BACKLOG)
3549 ssh_throttle_all(ssh, 0, bufsize);
3553 * Connect to specified host and port.
3554 * Returns an error message, or NULL on success.
3555 * Also places the canonical host name into `realhost'. It must be
3556 * freed by the caller.
3558 static const char *connect_to_host(Ssh ssh, const char *host, int port,
3559 char **realhost, int nodelay, int keepalive)
3561 static const struct plug_function_table fn_table = {
3572 int addressfamily, sshprot;
3574 loghost = conf_get_str(ssh->conf, CONF_loghost);
3579 tmphost = dupstr(loghost);
3580 ssh->savedport = 22; /* default ssh port */
3583 * A colon suffix on the hostname string also lets us affect
3584 * savedport. (Unless there are multiple colons, in which case
3585 * we assume this is an unbracketed IPv6 literal.)
3587 colon = host_strrchr(tmphost, ':');
3588 if (colon && colon == host_strchr(tmphost, ':')) {
3591 ssh->savedport = atoi(colon);
3594 ssh->savedhost = host_strduptrim(tmphost);
3597 ssh->savedhost = host_strduptrim(host);
3599 port = 22; /* default ssh port */
3600 ssh->savedport = port;
3603 ssh->fn = &fn_table; /* make 'ssh' usable as a Plug */
3606 * Try connection-sharing, in case that means we don't open a
3607 * socket after all. ssh_connection_sharing_init will connect to a
3608 * previously established upstream if it can, and failing that,
3609 * establish a listening socket for _us_ to be the upstream. In
3610 * the latter case it will return NULL just as if it had done
3611 * nothing, because here we only need to care if we're a
3612 * downstream and need to do our connection setup differently.
3614 ssh->connshare = NULL;
3615 ssh->attempting_connshare = TRUE; /* affects socket logging behaviour */
3616 ssh->s = ssh_connection_sharing_init(ssh->savedhost, ssh->savedport,
3617 ssh->conf, ssh, &ssh->connshare);
3618 ssh->attempting_connshare = FALSE;
3619 if (ssh->s != NULL) {
3621 * We are a downstream.
3623 ssh->bare_connection = TRUE;
3624 ssh->do_ssh_init = do_ssh_connection_init;
3625 ssh->fullhostname = NULL;
3626 *realhost = dupstr(host); /* best we can do */
3629 * We're not a downstream, so open a normal socket.
3631 ssh->do_ssh_init = do_ssh_init;
3636 addressfamily = conf_get_int(ssh->conf, CONF_addressfamily);
3637 logeventf(ssh, "Looking up host \"%s\"%s", host,
3638 (addressfamily == ADDRTYPE_IPV4 ? " (IPv4)" :
3639 (addressfamily == ADDRTYPE_IPV6 ? " (IPv6)" : "")));
3640 addr = name_lookup(host, port, realhost, ssh->conf, addressfamily);
3641 if ((err = sk_addr_error(addr)) != NULL) {
3645 ssh->fullhostname = dupstr(*realhost); /* save in case of GSSAPI */
3647 ssh->s = new_connection(addr, *realhost, port,
3648 0, 1, nodelay, keepalive,
3649 (Plug) ssh, ssh->conf);
3650 if ((err = sk_socket_error(ssh->s)) != NULL) {
3652 notify_remote_exit(ssh->frontend);
3658 * If the SSH version number's fixed, set it now, and if it's SSH-2,
3659 * send the version string too.
3661 sshprot = conf_get_int(ssh->conf, CONF_sshprot);
3664 if (sshprot == 3 && !ssh->bare_connection) {
3666 ssh_send_verstring(ssh, "SSH-", NULL);
3670 * loghost, if configured, overrides realhost.
3674 *realhost = dupstr(loghost);
3681 * Throttle or unthrottle the SSH connection.
3683 static void ssh_throttle_conn(Ssh ssh, int adjust)
3685 int old_count = ssh->conn_throttle_count;
3686 ssh->conn_throttle_count += adjust;
3687 assert(ssh->conn_throttle_count >= 0);
3688 if (ssh->conn_throttle_count && !old_count) {
3689 ssh_set_frozen(ssh, 1);
3690 } else if (!ssh->conn_throttle_count && old_count) {
3691 ssh_set_frozen(ssh, 0);
3696 * Throttle or unthrottle _all_ local data streams (for when sends
3697 * on the SSH connection itself back up).
3699 static void ssh_throttle_all(Ssh ssh, int enable, int bufsize)
3702 struct ssh_channel *c;
3704 if (enable == ssh->throttled_all)
3706 ssh->throttled_all = enable;
3707 ssh->overall_bufsize = bufsize;
3710 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
3712 case CHAN_MAINSESSION:
3714 * This is treated separately, outside the switch.
3718 x11_override_throttle(c->u.x11.xconn, enable);
3721 /* Agent channels require no buffer management. */
3724 pfd_override_throttle(c->u.pfd.pf, enable);
3730 static void ssh_agent_callback(void *sshv, void *reply, int replylen)
3732 Ssh ssh = (Ssh) sshv;
3734 ssh->agent_response = reply;
3735 ssh->agent_response_len = replylen;
3737 if (ssh->version == 1)
3738 do_ssh1_login(ssh, NULL, -1, NULL);
3740 do_ssh2_authconn(ssh, NULL, -1, NULL);
3743 static void ssh_dialog_callback(void *sshv, int ret)
3745 Ssh ssh = (Ssh) sshv;
3747 ssh->user_response = ret;
3749 if (ssh->version == 1)
3750 do_ssh1_login(ssh, NULL, -1, NULL);
3752 do_ssh2_transport(ssh, NULL, -1, NULL);
3755 * This may have unfrozen the SSH connection, so do a
3758 ssh_process_queued_incoming_data(ssh);
3761 static void ssh_agentf_callback(void *cv, void *reply, int replylen)
3763 struct ssh_channel *c = (struct ssh_channel *)cv;
3765 const void *sentreply = reply;
3767 c->u.a.outstanding_requests--;
3769 /* Fake SSH_AGENT_FAILURE. */
3770 sentreply = "\0\0\0\1\5";
3773 if (ssh->version == 2) {
3774 ssh2_add_channel_data(c, sentreply, replylen);
3777 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
3778 PKT_INT, c->remoteid,
3780 PKT_DATA, sentreply, replylen,
3786 * If we've already seen an incoming EOF but haven't sent an
3787 * outgoing one, this may be the moment to send it.
3789 if (c->u.a.outstanding_requests == 0 && (c->closes & CLOSES_RCVD_EOF))
3790 sshfwd_write_eof(c);
3794 * Client-initiated disconnection. Send a DISCONNECT if `wire_reason'
3795 * non-NULL, otherwise just close the connection. `client_reason' == NULL
3796 * => log `wire_reason'.
3798 static void ssh_disconnect(Ssh ssh, const char *client_reason,
3799 const char *wire_reason,
3800 int code, int clean_exit)
3804 client_reason = wire_reason;
3806 error = dupprintf("Disconnected: %s", client_reason);
3808 error = dupstr("Disconnected");
3810 if (ssh->version == 1) {
3811 send_packet(ssh, SSH1_MSG_DISCONNECT, PKT_STR, wire_reason,
3813 } else if (ssh->version == 2) {
3814 struct Packet *pktout = ssh2_pkt_init(SSH2_MSG_DISCONNECT);
3815 ssh2_pkt_adduint32(pktout, code);
3816 ssh2_pkt_addstring(pktout, wire_reason);
3817 ssh2_pkt_addstring(pktout, "en"); /* language tag */
3818 ssh2_pkt_send_noqueue(ssh, pktout);
3821 ssh->close_expected = TRUE;
3822 ssh->clean_exit = clean_exit;
3823 ssh_closing((Plug)ssh, error, 0, 0);
3827 int verify_ssh_manual_host_key(Ssh ssh, const char *fingerprint,
3828 const struct ssh_signkey *ssh2keytype,
3831 if (!conf_get_str_nthstrkey(ssh->conf, CONF_ssh_manual_hostkeys, 0)) {
3832 return -1; /* no manual keys configured */
3837 * The fingerprint string we've been given will have things
3838 * like 'ssh-rsa 2048' at the front of it. Strip those off and
3839 * narrow down to just the colon-separated hex block at the
3840 * end of the string.
3842 const char *p = strrchr(fingerprint, ' ');
3843 fingerprint = p ? p+1 : fingerprint;
3844 /* Quick sanity checks, including making sure it's in lowercase */
3845 assert(strlen(fingerprint) == 16*3 - 1);
3846 assert(fingerprint[2] == ':');
3847 assert(fingerprint[strspn(fingerprint, "0123456789abcdef:")] == 0);
3849 if (conf_get_str_str_opt(ssh->conf, CONF_ssh_manual_hostkeys,
3851 return 1; /* success */
3856 * Construct the base64-encoded public key blob and see if
3859 unsigned char *binblob;
3861 int binlen, atoms, i;
3862 binblob = ssh2keytype->public_blob(ssh2keydata, &binlen);
3863 atoms = (binlen + 2) / 3;
3864 base64blob = snewn(atoms * 4 + 1, char);
3865 for (i = 0; i < atoms; i++)
3866 base64_encode_atom(binblob + 3*i, binlen - 3*i, base64blob + 4*i);
3867 base64blob[atoms * 4] = '\0';
3869 if (conf_get_str_str_opt(ssh->conf, CONF_ssh_manual_hostkeys,
3872 return 1; /* success */
3881 * Handle the key exchange and user authentication phases.
3883 static int do_ssh1_login(Ssh ssh, const unsigned char *in, int inlen,
3884 struct Packet *pktin)
3887 unsigned char cookie[8], *ptr;
3888 struct MD5Context md5c;
3889 struct do_ssh1_login_state {
3892 unsigned char *rsabuf;
3893 const unsigned char *keystr1, *keystr2;
3894 unsigned long supported_ciphers_mask, supported_auths_mask;
3895 int tried_publickey, tried_agent;
3896 int tis_auth_refused, ccard_auth_refused;
3897 unsigned char session_id[16];
3899 void *publickey_blob;
3900 int publickey_bloblen;
3901 char *publickey_comment;
3902 int privatekey_available, privatekey_encrypted;
3903 prompts_t *cur_prompt;
3906 unsigned char request[5], *response, *p;
3916 struct RSAKey servkey, hostkey;
3918 crState(do_ssh1_login_state);
3925 if (pktin->type != SSH1_SMSG_PUBLIC_KEY) {
3926 bombout(("Public key packet not received"));
3930 logevent("Received public keys");
3932 ptr = ssh_pkt_getdata(pktin, 8);
3934 bombout(("SSH-1 public key packet stopped before random cookie"));
3937 memcpy(cookie, ptr, 8);
3939 if (!ssh1_pkt_getrsakey(pktin, &s->servkey, &s->keystr1) ||
3940 !ssh1_pkt_getrsakey(pktin, &s->hostkey, &s->keystr2)) {
3941 bombout(("Failed to read SSH-1 public keys from public key packet"));
3946 * Log the host key fingerprint.
3950 logevent("Host key fingerprint is:");
3951 strcpy(logmsg, " ");
3952 s->hostkey.comment = NULL;
3953 rsa_fingerprint(logmsg + strlen(logmsg),
3954 sizeof(logmsg) - strlen(logmsg), &s->hostkey);
3958 ssh->v1_remote_protoflags = ssh_pkt_getuint32(pktin);
3959 s->supported_ciphers_mask = ssh_pkt_getuint32(pktin);
3960 s->supported_auths_mask = ssh_pkt_getuint32(pktin);
3961 if ((ssh->remote_bugs & BUG_CHOKES_ON_RSA))
3962 s->supported_auths_mask &= ~(1 << SSH1_AUTH_RSA);
3964 ssh->v1_local_protoflags =
3965 ssh->v1_remote_protoflags & SSH1_PROTOFLAGS_SUPPORTED;
3966 ssh->v1_local_protoflags |= SSH1_PROTOFLAG_SCREEN_NUMBER;
3969 MD5Update(&md5c, s->keystr2, s->hostkey.bytes);
3970 MD5Update(&md5c, s->keystr1, s->servkey.bytes);
3971 MD5Update(&md5c, cookie, 8);
3972 MD5Final(s->session_id, &md5c);
3974 for (i = 0; i < 32; i++)
3975 ssh->session_key[i] = random_byte();
3978 * Verify that the `bits' and `bytes' parameters match.
3980 if (s->hostkey.bits > s->hostkey.bytes * 8 ||
3981 s->servkey.bits > s->servkey.bytes * 8) {
3982 bombout(("SSH-1 public keys were badly formatted"));
3986 s->len = (s->hostkey.bytes > s->servkey.bytes ?
3987 s->hostkey.bytes : s->servkey.bytes);
3989 s->rsabuf = snewn(s->len, unsigned char);
3992 * Verify the host key.
3996 * First format the key into a string.
3998 int len = rsastr_len(&s->hostkey);
3999 char fingerprint[100];
4000 char *keystr = snewn(len, char);
4001 rsastr_fmt(keystr, &s->hostkey);
4002 rsa_fingerprint(fingerprint, sizeof(fingerprint), &s->hostkey);
4004 /* First check against manually configured host keys. */
4005 s->dlgret = verify_ssh_manual_host_key(ssh, fingerprint, NULL, NULL);
4006 if (s->dlgret == 0) { /* did not match */
4007 bombout(("Host key did not appear in manually configured list"));
4010 } else if (s->dlgret < 0) { /* none configured; use standard handling */
4011 ssh_set_frozen(ssh, 1);
4012 s->dlgret = verify_ssh_host_key(ssh->frontend,
4013 ssh->savedhost, ssh->savedport,
4014 "rsa", keystr, fingerprint,
4015 ssh_dialog_callback, ssh);
4017 if (s->dlgret < 0) {
4021 bombout(("Unexpected data from server while waiting"
4022 " for user host key response"));
4025 } while (pktin || inlen > 0);
4026 s->dlgret = ssh->user_response;
4028 ssh_set_frozen(ssh, 0);
4030 if (s->dlgret == 0) {
4031 ssh_disconnect(ssh, "User aborted at host key verification",
4040 for (i = 0; i < 32; i++) {
4041 s->rsabuf[i] = ssh->session_key[i];
4043 s->rsabuf[i] ^= s->session_id[i];
4046 if (s->hostkey.bytes > s->servkey.bytes) {
4047 ret = rsaencrypt(s->rsabuf, 32, &s->servkey);
4049 ret = rsaencrypt(s->rsabuf, s->servkey.bytes, &s->hostkey);
4051 ret = rsaencrypt(s->rsabuf, 32, &s->hostkey);
4053 ret = rsaencrypt(s->rsabuf, s->hostkey.bytes, &s->servkey);
4056 bombout(("SSH-1 public key encryptions failed due to bad formatting"));
4060 logevent("Encrypted session key");
4063 int cipher_chosen = 0, warn = 0;
4064 const char *cipher_string = NULL;
4066 for (i = 0; !cipher_chosen && i < CIPHER_MAX; i++) {
4067 int next_cipher = conf_get_int_int(ssh->conf,
4068 CONF_ssh_cipherlist, i);
4069 if (next_cipher == CIPHER_WARN) {
4070 /* If/when we choose a cipher, warn about it */
4072 } else if (next_cipher == CIPHER_AES) {
4073 /* XXX Probably don't need to mention this. */
4074 logevent("AES not supported in SSH-1, skipping");
4076 switch (next_cipher) {
4077 case CIPHER_3DES: s->cipher_type = SSH_CIPHER_3DES;
4078 cipher_string = "3DES"; break;
4079 case CIPHER_BLOWFISH: s->cipher_type = SSH_CIPHER_BLOWFISH;
4080 cipher_string = "Blowfish"; break;
4081 case CIPHER_DES: s->cipher_type = SSH_CIPHER_DES;
4082 cipher_string = "single-DES"; break;
4084 if (s->supported_ciphers_mask & (1 << s->cipher_type))
4088 if (!cipher_chosen) {
4089 if ((s->supported_ciphers_mask & (1 << SSH_CIPHER_3DES)) == 0)
4090 bombout(("Server violates SSH-1 protocol by not "
4091 "supporting 3DES encryption"));
4093 /* shouldn't happen */
4094 bombout(("No supported ciphers found"));
4098 /* Warn about chosen cipher if necessary. */
4100 ssh_set_frozen(ssh, 1);
4101 s->dlgret = askalg(ssh->frontend, "cipher", cipher_string,
4102 ssh_dialog_callback, ssh);
4103 if (s->dlgret < 0) {
4107 bombout(("Unexpected data from server while waiting"
4108 " for user response"));
4111 } while (pktin || inlen > 0);
4112 s->dlgret = ssh->user_response;
4114 ssh_set_frozen(ssh, 0);
4115 if (s->dlgret == 0) {
4116 ssh_disconnect(ssh, "User aborted at cipher warning", NULL,
4123 switch (s->cipher_type) {
4124 case SSH_CIPHER_3DES:
4125 logevent("Using 3DES encryption");
4127 case SSH_CIPHER_DES:
4128 logevent("Using single-DES encryption");
4130 case SSH_CIPHER_BLOWFISH:
4131 logevent("Using Blowfish encryption");
4135 send_packet(ssh, SSH1_CMSG_SESSION_KEY,
4136 PKT_CHAR, s->cipher_type,
4137 PKT_DATA, cookie, 8,
4138 PKT_CHAR, (s->len * 8) >> 8, PKT_CHAR, (s->len * 8) & 0xFF,
4139 PKT_DATA, s->rsabuf, s->len,
4140 PKT_INT, ssh->v1_local_protoflags, PKT_END);
4142 logevent("Trying to enable encryption...");
4146 ssh->cipher = (s->cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 :
4147 s->cipher_type == SSH_CIPHER_DES ? &ssh_des :
4149 ssh->v1_cipher_ctx = ssh->cipher->make_context();
4150 ssh->cipher->sesskey(ssh->v1_cipher_ctx, ssh->session_key);
4151 logeventf(ssh, "Initialised %s encryption", ssh->cipher->text_name);
4153 ssh->crcda_ctx = crcda_make_context();
4154 logevent("Installing CRC compensation attack detector");
4156 if (s->servkey.modulus) {
4157 sfree(s->servkey.modulus);
4158 s->servkey.modulus = NULL;
4160 if (s->servkey.exponent) {
4161 sfree(s->servkey.exponent);
4162 s->servkey.exponent = NULL;
4164 if (s->hostkey.modulus) {
4165 sfree(s->hostkey.modulus);
4166 s->hostkey.modulus = NULL;
4168 if (s->hostkey.exponent) {
4169 sfree(s->hostkey.exponent);
4170 s->hostkey.exponent = NULL;
4174 if (pktin->type != SSH1_SMSG_SUCCESS) {
4175 bombout(("Encryption not successfully enabled"));
4179 logevent("Successfully started encryption");
4181 fflush(stdout); /* FIXME eh? */
4183 if ((ssh->username = get_remote_username(ssh->conf)) == NULL) {
4184 int ret; /* need not be kept over crReturn */
4185 s->cur_prompt = new_prompts(ssh->frontend);
4186 s->cur_prompt->to_server = TRUE;
4187 s->cur_prompt->name = dupstr("SSH login name");
4188 add_prompt(s->cur_prompt, dupstr("login as: "), TRUE);
4189 ret = get_userpass_input(s->cur_prompt, NULL, 0);
4192 crWaitUntil(!pktin);
4193 ret = get_userpass_input(s->cur_prompt, in, inlen);
4198 * Failed to get a username. Terminate.
4200 free_prompts(s->cur_prompt);
4201 ssh_disconnect(ssh, "No username provided", NULL, 0, TRUE);
4204 ssh->username = dupstr(s->cur_prompt->prompts[0]->result);
4205 free_prompts(s->cur_prompt);
4208 send_packet(ssh, SSH1_CMSG_USER, PKT_STR, ssh->username, PKT_END);
4210 char *userlog = dupprintf("Sent username \"%s\"", ssh->username);
4212 if (flags & FLAG_INTERACTIVE &&
4213 (!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) {
4214 c_write_str(ssh, userlog);
4215 c_write_str(ssh, "\r\n");
4223 if ((s->supported_auths_mask & (1 << SSH1_AUTH_RSA)) == 0) {
4224 /* We must not attempt PK auth. Pretend we've already tried it. */
4225 s->tried_publickey = s->tried_agent = 1;
4227 s->tried_publickey = s->tried_agent = 0;
4229 s->tis_auth_refused = s->ccard_auth_refused = 0;
4231 * Load the public half of any configured keyfile for later use.
4233 s->keyfile = conf_get_filename(ssh->conf, CONF_keyfile);
4234 if (!filename_is_null(s->keyfile)) {
4236 logeventf(ssh, "Reading key file \"%.150s\"",
4237 filename_to_str(s->keyfile));
4238 keytype = key_type(s->keyfile);
4239 if (keytype == SSH_KEYTYPE_SSH1 ||
4240 keytype == SSH_KEYTYPE_SSH1_PUBLIC) {
4242 if (rsakey_pubblob(s->keyfile,
4243 &s->publickey_blob, &s->publickey_bloblen,
4244 &s->publickey_comment, &error)) {
4245 s->privatekey_available = (keytype == SSH_KEYTYPE_SSH1);
4246 if (!s->privatekey_available)
4247 logeventf(ssh, "Key file contains public key only");
4248 s->privatekey_encrypted = rsakey_encrypted(s->keyfile,
4252 logeventf(ssh, "Unable to load key (%s)", error);
4253 msgbuf = dupprintf("Unable to load key file "
4254 "\"%.150s\" (%s)\r\n",
4255 filename_to_str(s->keyfile),
4257 c_write_str(ssh, msgbuf);
4259 s->publickey_blob = NULL;
4263 logeventf(ssh, "Unable to use this key file (%s)",
4264 key_type_to_str(keytype));
4265 msgbuf = dupprintf("Unable to use key file \"%.150s\""
4267 filename_to_str(s->keyfile),
4268 key_type_to_str(keytype));
4269 c_write_str(ssh, msgbuf);
4271 s->publickey_blob = NULL;
4274 s->publickey_blob = NULL;
4276 while (pktin->type == SSH1_SMSG_FAILURE) {
4277 s->pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
4279 if (conf_get_int(ssh->conf, CONF_tryagent) && agent_exists() && !s->tried_agent) {
4281 * Attempt RSA authentication using Pageant.
4287 logevent("Pageant is running. Requesting keys.");
4289 /* Request the keys held by the agent. */
4290 PUT_32BIT(s->request, 1);
4291 s->request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES;
4292 if (!agent_query(s->request, 5, &r, &s->responselen,
4293 ssh_agent_callback, ssh)) {
4297 bombout(("Unexpected data from server while waiting"
4298 " for agent response"));
4301 } while (pktin || inlen > 0);
4302 r = ssh->agent_response;
4303 s->responselen = ssh->agent_response_len;
4305 s->response = (unsigned char *) r;
4306 if (s->response && s->responselen >= 5 &&
4307 s->response[4] == SSH1_AGENT_RSA_IDENTITIES_ANSWER) {
4308 s->p = s->response + 5;
4309 s->nkeys = toint(GET_32BIT(s->p));
4311 logeventf(ssh, "Pageant reported negative key count %d",
4316 logeventf(ssh, "Pageant has %d SSH-1 keys", s->nkeys);
4317 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
4318 unsigned char *pkblob = s->p;
4322 do { /* do while (0) to make breaking easy */
4323 n = ssh1_read_bignum
4324 (s->p, toint(s->responselen-(s->p-s->response)),
4329 n = ssh1_read_bignum
4330 (s->p, toint(s->responselen-(s->p-s->response)),
4335 if (s->responselen - (s->p-s->response) < 4)
4337 s->commentlen = toint(GET_32BIT(s->p));
4339 if (s->commentlen < 0 ||
4340 toint(s->responselen - (s->p-s->response)) <
4343 s->commentp = (char *)s->p;
4344 s->p += s->commentlen;
4348 logevent("Pageant key list packet was truncated");
4352 if (s->publickey_blob) {
4353 if (!memcmp(pkblob, s->publickey_blob,
4354 s->publickey_bloblen)) {
4355 logeventf(ssh, "Pageant key #%d matches "
4356 "configured key file", s->keyi);
4357 s->tried_publickey = 1;
4359 /* Skip non-configured key */
4362 logeventf(ssh, "Trying Pageant key #%d", s->keyi);
4363 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
4364 PKT_BIGNUM, s->key.modulus, PKT_END);
4366 if (pktin->type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
4367 logevent("Key refused");
4370 logevent("Received RSA challenge");
4371 if ((s->challenge = ssh1_pkt_getmp(pktin)) == NULL) {
4372 bombout(("Server's RSA challenge was badly formatted"));
4377 char *agentreq, *q, *ret;
4380 len = 1 + 4; /* message type, bit count */
4381 len += ssh1_bignum_length(s->key.exponent);
4382 len += ssh1_bignum_length(s->key.modulus);
4383 len += ssh1_bignum_length(s->challenge);
4384 len += 16; /* session id */
4385 len += 4; /* response format */
4386 agentreq = snewn(4 + len, char);
4387 PUT_32BIT(agentreq, len);
4389 *q++ = SSH1_AGENTC_RSA_CHALLENGE;
4390 PUT_32BIT(q, bignum_bitcount(s->key.modulus));
4392 q += ssh1_write_bignum(q, s->key.exponent);
4393 q += ssh1_write_bignum(q, s->key.modulus);
4394 q += ssh1_write_bignum(q, s->challenge);
4395 memcpy(q, s->session_id, 16);
4397 PUT_32BIT(q, 1); /* response format */
4398 if (!agent_query(agentreq, len + 4, &vret, &retlen,
4399 ssh_agent_callback, ssh)) {
4404 bombout(("Unexpected data from server"
4405 " while waiting for agent"
4409 } while (pktin || inlen > 0);
4410 vret = ssh->agent_response;
4411 retlen = ssh->agent_response_len;
4416 if (ret[4] == SSH1_AGENT_RSA_RESPONSE) {
4417 logevent("Sending Pageant's response");
4418 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
4419 PKT_DATA, ret + 5, 16,
4423 if (pktin->type == SSH1_SMSG_SUCCESS) {
4425 ("Pageant's response accepted");
4426 if (flags & FLAG_VERBOSE) {
4427 c_write_str(ssh, "Authenticated using"
4429 c_write(ssh, s->commentp,
4431 c_write_str(ssh, "\" from agent\r\n");
4436 ("Pageant's response not accepted");
4439 ("Pageant failed to answer challenge");
4443 logevent("No reply received from Pageant");
4446 freebn(s->key.exponent);
4447 freebn(s->key.modulus);
4448 freebn(s->challenge);
4453 if (s->publickey_blob && !s->tried_publickey)
4454 logevent("Configured key file not in Pageant");
4456 logevent("Failed to get reply from Pageant");
4461 if (s->publickey_blob && s->privatekey_available &&
4462 !s->tried_publickey) {
4464 * Try public key authentication with the specified
4467 int got_passphrase; /* need not be kept over crReturn */
4468 if (flags & FLAG_VERBOSE)
4469 c_write_str(ssh, "Trying public key authentication.\r\n");
4470 s->keyfile = conf_get_filename(ssh->conf, CONF_keyfile);
4471 logeventf(ssh, "Trying public key \"%s\"",
4472 filename_to_str(s->keyfile));
4473 s->tried_publickey = 1;
4474 got_passphrase = FALSE;
4475 while (!got_passphrase) {
4477 * Get a passphrase, if necessary.
4479 char *passphrase = NULL; /* only written after crReturn */
4481 if (!s->privatekey_encrypted) {
4482 if (flags & FLAG_VERBOSE)
4483 c_write_str(ssh, "No passphrase required.\r\n");
4486 int ret; /* need not be kept over crReturn */
4487 s->cur_prompt = new_prompts(ssh->frontend);
4488 s->cur_prompt->to_server = FALSE;
4489 s->cur_prompt->name = dupstr("SSH key passphrase");
4490 add_prompt(s->cur_prompt,
4491 dupprintf("Passphrase for key \"%.100s\": ",
4492 s->publickey_comment), FALSE);
4493 ret = get_userpass_input(s->cur_prompt, NULL, 0);
4496 crWaitUntil(!pktin);
4497 ret = get_userpass_input(s->cur_prompt, in, inlen);
4501 /* Failed to get a passphrase. Terminate. */
4502 free_prompts(s->cur_prompt);
4503 ssh_disconnect(ssh, NULL, "Unable to authenticate",
4507 passphrase = dupstr(s->cur_prompt->prompts[0]->result);
4508 free_prompts(s->cur_prompt);
4511 * Try decrypting key with passphrase.
4513 s->keyfile = conf_get_filename(ssh->conf, CONF_keyfile);
4514 ret = loadrsakey(s->keyfile, &s->key, passphrase,
4517 smemclr(passphrase, strlen(passphrase));
4521 /* Correct passphrase. */
4522 got_passphrase = TRUE;
4523 } else if (ret == 0) {
4524 c_write_str(ssh, "Couldn't load private key from ");
4525 c_write_str(ssh, filename_to_str(s->keyfile));
4526 c_write_str(ssh, " (");
4527 c_write_str(ssh, error);
4528 c_write_str(ssh, ").\r\n");
4529 got_passphrase = FALSE;
4530 break; /* go and try something else */
4531 } else if (ret == -1) {
4532 c_write_str(ssh, "Wrong passphrase.\r\n"); /* FIXME */
4533 got_passphrase = FALSE;
4536 assert(0 && "unexpected return from loadrsakey()");
4537 got_passphrase = FALSE; /* placate optimisers */
4541 if (got_passphrase) {
4544 * Send a public key attempt.
4546 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
4547 PKT_BIGNUM, s->key.modulus, PKT_END);
4550 if (pktin->type == SSH1_SMSG_FAILURE) {
4551 c_write_str(ssh, "Server refused our public key.\r\n");
4552 continue; /* go and try something else */
4554 if (pktin->type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
4555 bombout(("Bizarre response to offer of public key"));
4561 unsigned char buffer[32];
4562 Bignum challenge, response;
4564 if ((challenge = ssh1_pkt_getmp(pktin)) == NULL) {
4565 bombout(("Server's RSA challenge was badly formatted"));
4568 response = rsadecrypt(challenge, &s->key);
4569 freebn(s->key.private_exponent);/* burn the evidence */
4571 for (i = 0; i < 32; i++) {
4572 buffer[i] = bignum_byte(response, 31 - i);
4576 MD5Update(&md5c, buffer, 32);
4577 MD5Update(&md5c, s->session_id, 16);
4578 MD5Final(buffer, &md5c);
4580 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
4581 PKT_DATA, buffer, 16, PKT_END);
4588 if (pktin->type == SSH1_SMSG_FAILURE) {
4589 if (flags & FLAG_VERBOSE)
4590 c_write_str(ssh, "Failed to authenticate with"
4591 " our public key.\r\n");
4592 continue; /* go and try something else */
4593 } else if (pktin->type != SSH1_SMSG_SUCCESS) {
4594 bombout(("Bizarre response to RSA authentication response"));
4598 break; /* we're through! */
4604 * Otherwise, try various forms of password-like authentication.
4606 s->cur_prompt = new_prompts(ssh->frontend);
4608 if (conf_get_int(ssh->conf, CONF_try_tis_auth) &&
4609 (s->supported_auths_mask & (1 << SSH1_AUTH_TIS)) &&
4610 !s->tis_auth_refused) {
4611 s->pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
4612 logevent("Requested TIS authentication");
4613 send_packet(ssh, SSH1_CMSG_AUTH_TIS, PKT_END);
4615 if (pktin->type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
4616 logevent("TIS authentication declined");
4617 if (flags & FLAG_INTERACTIVE)
4618 c_write_str(ssh, "TIS authentication refused.\r\n");
4619 s->tis_auth_refused = 1;
4624 char *instr_suf, *prompt;
4626 ssh_pkt_getstring(pktin, &challenge, &challengelen);
4628 bombout(("TIS challenge packet was badly formed"));
4631 logevent("Received TIS challenge");
4632 s->cur_prompt->to_server = TRUE;
4633 s->cur_prompt->name = dupstr("SSH TIS authentication");
4634 /* Prompt heuristic comes from OpenSSH */
4635 if (memchr(challenge, '\n', challengelen)) {
4636 instr_suf = dupstr("");
4637 prompt = dupprintf("%.*s", challengelen, challenge);
4639 instr_suf = dupprintf("%.*s", challengelen, challenge);
4640 prompt = dupstr("Response: ");
4642 s->cur_prompt->instruction =
4643 dupprintf("Using TIS authentication.%s%s",
4644 (*instr_suf) ? "\n" : "",
4646 s->cur_prompt->instr_reqd = TRUE;
4647 add_prompt(s->cur_prompt, prompt, FALSE);
4651 if (conf_get_int(ssh->conf, CONF_try_tis_auth) &&
4652 (s->supported_auths_mask & (1 << SSH1_AUTH_CCARD)) &&
4653 !s->ccard_auth_refused) {
4654 s->pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE;
4655 logevent("Requested CryptoCard authentication");
4656 send_packet(ssh, SSH1_CMSG_AUTH_CCARD, PKT_END);
4658 if (pktin->type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
4659 logevent("CryptoCard authentication declined");
4660 c_write_str(ssh, "CryptoCard authentication refused.\r\n");
4661 s->ccard_auth_refused = 1;
4666 char *instr_suf, *prompt;
4668 ssh_pkt_getstring(pktin, &challenge, &challengelen);
4670 bombout(("CryptoCard challenge packet was badly formed"));
4673 logevent("Received CryptoCard challenge");
4674 s->cur_prompt->to_server = TRUE;
4675 s->cur_prompt->name = dupstr("SSH CryptoCard authentication");
4676 s->cur_prompt->name_reqd = FALSE;
4677 /* Prompt heuristic comes from OpenSSH */
4678 if (memchr(challenge, '\n', challengelen)) {
4679 instr_suf = dupstr("");
4680 prompt = dupprintf("%.*s", challengelen, challenge);
4682 instr_suf = dupprintf("%.*s", challengelen, challenge);
4683 prompt = dupstr("Response: ");
4685 s->cur_prompt->instruction =
4686 dupprintf("Using CryptoCard authentication.%s%s",
4687 (*instr_suf) ? "\n" : "",
4689 s->cur_prompt->instr_reqd = TRUE;
4690 add_prompt(s->cur_prompt, prompt, FALSE);
4694 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
4695 if ((s->supported_auths_mask & (1 << SSH1_AUTH_PASSWORD)) == 0) {
4696 bombout(("No supported authentication methods available"));
4699 s->cur_prompt->to_server = TRUE;
4700 s->cur_prompt->name = dupstr("SSH password");
4701 add_prompt(s->cur_prompt, dupprintf("%s@%s's password: ",
4702 ssh->username, ssh->savedhost),
4707 * Show password prompt, having first obtained it via a TIS
4708 * or CryptoCard exchange if we're doing TIS or CryptoCard
4712 int ret; /* need not be kept over crReturn */
4713 ret = get_userpass_input(s->cur_prompt, NULL, 0);
4716 crWaitUntil(!pktin);
4717 ret = get_userpass_input(s->cur_prompt, in, inlen);
4722 * Failed to get a password (for example
4723 * because one was supplied on the command line
4724 * which has already failed to work). Terminate.
4726 free_prompts(s->cur_prompt);
4727 ssh_disconnect(ssh, NULL, "Unable to authenticate", 0, TRUE);
4732 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
4734 * Defence against traffic analysis: we send a
4735 * whole bunch of packets containing strings of
4736 * different lengths. One of these strings is the
4737 * password, in a SSH1_CMSG_AUTH_PASSWORD packet.
4738 * The others are all random data in
4739 * SSH1_MSG_IGNORE packets. This way a passive
4740 * listener can't tell which is the password, and
4741 * hence can't deduce the password length.
4743 * Anybody with a password length greater than 16
4744 * bytes is going to have enough entropy in their
4745 * password that a listener won't find it _that_
4746 * much help to know how long it is. So what we'll
4749 * - if password length < 16, we send 15 packets
4750 * containing string lengths 1 through 15
4752 * - otherwise, we let N be the nearest multiple
4753 * of 8 below the password length, and send 8
4754 * packets containing string lengths N through
4755 * N+7. This won't obscure the order of
4756 * magnitude of the password length, but it will
4757 * introduce a bit of extra uncertainty.
4759 * A few servers can't deal with SSH1_MSG_IGNORE, at
4760 * least in this context. For these servers, we need
4761 * an alternative defence. We make use of the fact
4762 * that the password is interpreted as a C string:
4763 * so we can append a NUL, then some random data.
4765 * A few servers can deal with neither SSH1_MSG_IGNORE
4766 * here _nor_ a padded password string.
4767 * For these servers we are left with no defences
4768 * against password length sniffing.
4770 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE) &&
4771 !(ssh->remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) {
4773 * The server can deal with SSH1_MSG_IGNORE, so
4774 * we can use the primary defence.
4776 int bottom, top, pwlen, i;
4779 pwlen = strlen(s->cur_prompt->prompts[0]->result);
4781 bottom = 0; /* zero length passwords are OK! :-) */
4784 bottom = pwlen & ~7;
4788 assert(pwlen >= bottom && pwlen <= top);
4790 randomstr = snewn(top + 1, char);
4792 for (i = bottom; i <= top; i++) {
4794 defer_packet(ssh, s->pwpkt_type,
4795 PKT_STR,s->cur_prompt->prompts[0]->result,
4798 for (j = 0; j < i; j++) {
4800 randomstr[j] = random_byte();
4801 } while (randomstr[j] == '\0');
4803 randomstr[i] = '\0';
4804 defer_packet(ssh, SSH1_MSG_IGNORE,
4805 PKT_STR, randomstr, PKT_END);
4808 logevent("Sending password with camouflage packets");
4809 ssh_pkt_defersend(ssh);
4812 else if (!(ssh->remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) {
4814 * The server can't deal with SSH1_MSG_IGNORE
4815 * but can deal with padded passwords, so we
4816 * can use the secondary defence.
4822 len = strlen(s->cur_prompt->prompts[0]->result);
4823 if (len < sizeof(string)) {
4825 strcpy(string, s->cur_prompt->prompts[0]->result);
4826 len++; /* cover the zero byte */
4827 while (len < sizeof(string)) {
4828 string[len++] = (char) random_byte();
4831 ss = s->cur_prompt->prompts[0]->result;
4833 logevent("Sending length-padded password");
4834 send_packet(ssh, s->pwpkt_type,
4835 PKT_INT, len, PKT_DATA, ss, len,
4839 * The server is believed unable to cope with
4840 * any of our password camouflage methods.
4843 len = strlen(s->cur_prompt->prompts[0]->result);
4844 logevent("Sending unpadded password");
4845 send_packet(ssh, s->pwpkt_type,
4847 PKT_DATA, s->cur_prompt->prompts[0]->result, len,
4851 send_packet(ssh, s->pwpkt_type,
4852 PKT_STR, s->cur_prompt->prompts[0]->result,
4855 logevent("Sent password");
4856 free_prompts(s->cur_prompt);
4858 if (pktin->type == SSH1_SMSG_FAILURE) {
4859 if (flags & FLAG_VERBOSE)
4860 c_write_str(ssh, "Access denied\r\n");
4861 logevent("Authentication refused");
4862 } else if (pktin->type != SSH1_SMSG_SUCCESS) {
4863 bombout(("Strange packet received, type %d", pktin->type));
4869 if (s->publickey_blob) {
4870 sfree(s->publickey_blob);
4871 sfree(s->publickey_comment);
4874 logevent("Authentication successful");
4879 static void ssh_channel_try_eof(struct ssh_channel *c)
4882 assert(c->pending_eof); /* precondition for calling us */
4884 return; /* can't close: not even opened yet */
4885 if (ssh->version == 2 && bufchain_size(&c->v.v2.outbuffer) > 0)
4886 return; /* can't send EOF: pending outgoing data */
4888 c->pending_eof = FALSE; /* we're about to send it */
4889 if (ssh->version == 1) {
4890 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid,
4892 c->closes |= CLOSES_SENT_EOF;
4894 struct Packet *pktout;
4895 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_EOF);
4896 ssh2_pkt_adduint32(pktout, c->remoteid);
4897 ssh2_pkt_send(ssh, pktout);
4898 c->closes |= CLOSES_SENT_EOF;
4899 ssh2_channel_check_close(c);
4903 Conf *sshfwd_get_conf(struct ssh_channel *c)
4909 void sshfwd_write_eof(struct ssh_channel *c)
4913 if (ssh->state == SSH_STATE_CLOSED)
4916 if (c->closes & CLOSES_SENT_EOF)
4919 c->pending_eof = TRUE;
4920 ssh_channel_try_eof(c);
4923 void sshfwd_unclean_close(struct ssh_channel *c, const char *err)
4927 if (ssh->state == SSH_STATE_CLOSED)
4932 x11_close(c->u.x11.xconn);
4933 logeventf(ssh, "Forwarded X11 connection terminated due to local "
4937 case CHAN_SOCKDATA_DORMANT:
4938 pfd_close(c->u.pfd.pf);
4939 logeventf(ssh, "Forwarded port closed due to local error: %s", err);
4942 c->type = CHAN_ZOMBIE;
4943 c->pending_eof = FALSE; /* this will confuse a zombie channel */
4945 ssh2_channel_check_close(c);
4948 int sshfwd_write(struct ssh_channel *c, char *buf, int len)
4952 if (ssh->state == SSH_STATE_CLOSED)
4955 if (ssh->version == 1) {
4956 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
4957 PKT_INT, c->remoteid,
4958 PKT_INT, len, PKT_DATA, buf, len,
4961 * In SSH-1 we can return 0 here - implying that forwarded
4962 * connections are never individually throttled - because
4963 * the only circumstance that can cause throttling will be
4964 * the whole SSH connection backing up, in which case
4965 * _everything_ will be throttled as a whole.
4969 ssh2_add_channel_data(c, buf, len);
4970 return ssh2_try_send(c);
4974 void sshfwd_unthrottle(struct ssh_channel *c, int bufsize)
4979 if (ssh->state == SSH_STATE_CLOSED)
4982 if (ssh->version == 1) {
4983 buflimit = SSH1_BUFFER_LIMIT;
4985 buflimit = c->v.v2.locmaxwin;
4986 ssh2_set_window(c, bufsize < buflimit ? buflimit - bufsize : 0);
4988 if (c->throttling_conn && bufsize <= buflimit) {
4989 c->throttling_conn = 0;
4990 ssh_throttle_conn(ssh, -1);
4994 static void ssh_queueing_handler(Ssh ssh, struct Packet *pktin)
4996 struct queued_handler *qh = ssh->qhead;
5000 assert(pktin->type == qh->msg1 || pktin->type == qh->msg2);
5003 assert(ssh->packet_dispatch[qh->msg1] == ssh_queueing_handler);
5004 ssh->packet_dispatch[qh->msg1] = ssh->q_saved_handler1;
5007 assert(ssh->packet_dispatch[qh->msg2] == ssh_queueing_handler);
5008 ssh->packet_dispatch[qh->msg2] = ssh->q_saved_handler2;
5012 ssh->qhead = qh->next;
5014 if (ssh->qhead->msg1 > 0) {
5015 ssh->q_saved_handler1 = ssh->packet_dispatch[ssh->qhead->msg1];
5016 ssh->packet_dispatch[ssh->qhead->msg1] = ssh_queueing_handler;
5018 if (ssh->qhead->msg2 > 0) {
5019 ssh->q_saved_handler2 = ssh->packet_dispatch[ssh->qhead->msg2];
5020 ssh->packet_dispatch[ssh->qhead->msg2] = ssh_queueing_handler;
5023 ssh->qhead = ssh->qtail = NULL;
5026 qh->handler(ssh, pktin, qh->ctx);
5031 static void ssh_queue_handler(Ssh ssh, int msg1, int msg2,
5032 chandler_fn_t handler, void *ctx)
5034 struct queued_handler *qh;
5036 qh = snew(struct queued_handler);
5039 qh->handler = handler;
5043 if (ssh->qtail == NULL) {
5047 ssh->q_saved_handler1 = ssh->packet_dispatch[ssh->qhead->msg1];
5048 ssh->packet_dispatch[qh->msg1] = ssh_queueing_handler;
5051 ssh->q_saved_handler2 = ssh->packet_dispatch[ssh->qhead->msg2];
5052 ssh->packet_dispatch[qh->msg2] = ssh_queueing_handler;
5055 ssh->qtail->next = qh;
5060 static void ssh_rportfwd_succfail(Ssh ssh, struct Packet *pktin, void *ctx)
5062 struct ssh_rportfwd *rpf, *pf = (struct ssh_rportfwd *)ctx;
5064 if (pktin->type == (ssh->version == 1 ? SSH1_SMSG_SUCCESS :
5065 SSH2_MSG_REQUEST_SUCCESS)) {
5066 logeventf(ssh, "Remote port forwarding from %s enabled",
5069 logeventf(ssh, "Remote port forwarding from %s refused",
5072 rpf = del234(ssh->rportfwds, pf);
5074 pf->pfrec->remote = NULL;
5079 int ssh_alloc_sharing_rportfwd(Ssh ssh, const char *shost, int sport,
5082 struct ssh_rportfwd *pf = snew(struct ssh_rportfwd);
5085 pf->share_ctx = share_ctx;
5086 pf->shost = dupstr(shost);
5088 pf->sportdesc = NULL;
5089 if (!ssh->rportfwds) {
5090 assert(ssh->version == 2);
5091 ssh->rportfwds = newtree234(ssh_rportcmp_ssh2);
5093 if (add234(ssh->rportfwds, pf) != pf) {
5101 static void ssh_sharing_global_request_response(Ssh ssh, struct Packet *pktin,
5104 share_got_pkt_from_server(ctx, pktin->type,
5105 pktin->body, pktin->length);
5108 void ssh_sharing_queue_global_request(Ssh ssh, void *share_ctx)
5110 ssh_queue_handler(ssh, SSH2_MSG_REQUEST_SUCCESS, SSH2_MSG_REQUEST_FAILURE,
5111 ssh_sharing_global_request_response, share_ctx);
5114 static void ssh_setup_portfwd(Ssh ssh, Conf *conf)
5116 struct ssh_portfwd *epf;
5120 if (!ssh->portfwds) {
5121 ssh->portfwds = newtree234(ssh_portcmp);
5124 * Go through the existing port forwardings and tag them
5125 * with status==DESTROY. Any that we want to keep will be
5126 * re-enabled (status==KEEP) as we go through the
5127 * configuration and find out which bits are the same as
5130 struct ssh_portfwd *epf;
5132 for (i = 0; (epf = index234(ssh->portfwds, i)) != NULL; i++)
5133 epf->status = DESTROY;
5136 for (val = conf_get_str_strs(conf, CONF_portfwd, NULL, &key);
5138 val = conf_get_str_strs(conf, CONF_portfwd, key, &key)) {
5139 char *kp, *kp2, *vp, *vp2;
5140 char address_family, type;
5141 int sport,dport,sserv,dserv;
5142 char *sports, *dports, *saddr, *host;
5146 address_family = 'A';
5148 if (*kp == 'A' || *kp == '4' || *kp == '6')
5149 address_family = *kp++;
5150 if (*kp == 'L' || *kp == 'R')
5153 if ((kp2 = host_strchr(kp, ':')) != NULL) {
5155 * There's a colon in the middle of the source port
5156 * string, which means that the part before it is
5157 * actually a source address.
5159 char *saddr_tmp = dupprintf("%.*s", (int)(kp2 - kp), kp);
5160 saddr = host_strduptrim(saddr_tmp);
5167 sport = atoi(sports);
5171 sport = net_service_lookup(sports);
5173 logeventf(ssh, "Service lookup failed for source"
5174 " port \"%s\"", sports);
5178 if (type == 'L' && !strcmp(val, "D")) {
5179 /* dynamic forwarding */
5186 /* ordinary forwarding */
5188 vp2 = vp + host_strcspn(vp, ":");
5189 host = dupprintf("%.*s", (int)(vp2 - vp), vp);
5193 dport = atoi(dports);
5197 dport = net_service_lookup(dports);
5199 logeventf(ssh, "Service lookup failed for destination"
5200 " port \"%s\"", dports);
5205 if (sport && dport) {
5206 /* Set up a description of the source port. */
5207 struct ssh_portfwd *pfrec, *epfrec;
5209 pfrec = snew(struct ssh_portfwd);
5211 pfrec->saddr = saddr;
5212 pfrec->sserv = sserv ? dupstr(sports) : NULL;
5213 pfrec->sport = sport;
5214 pfrec->daddr = host;
5215 pfrec->dserv = dserv ? dupstr(dports) : NULL;
5216 pfrec->dport = dport;
5217 pfrec->local = NULL;
5218 pfrec->remote = NULL;
5219 pfrec->addressfamily = (address_family == '4' ? ADDRTYPE_IPV4 :
5220 address_family == '6' ? ADDRTYPE_IPV6 :
5223 epfrec = add234(ssh->portfwds, pfrec);
5224 if (epfrec != pfrec) {
5225 if (epfrec->status == DESTROY) {
5227 * We already have a port forwarding up and running
5228 * with precisely these parameters. Hence, no need
5229 * to do anything; simply re-tag the existing one
5232 epfrec->status = KEEP;
5235 * Anything else indicates that there was a duplicate
5236 * in our input, which we'll silently ignore.
5238 free_portfwd(pfrec);
5240 pfrec->status = CREATE;
5249 * Now go through and destroy any port forwardings which were
5252 for (i = 0; (epf = index234(ssh->portfwds, i)) != NULL; i++)
5253 if (epf->status == DESTROY) {
5256 message = dupprintf("%s port forwarding from %s%s%d",
5257 epf->type == 'L' ? "local" :
5258 epf->type == 'R' ? "remote" : "dynamic",
5259 epf->saddr ? epf->saddr : "",
5260 epf->saddr ? ":" : "",
5263 if (epf->type != 'D') {
5264 char *msg2 = dupprintf("%s to %s:%d", message,
5265 epf->daddr, epf->dport);
5270 logeventf(ssh, "Cancelling %s", message);
5273 /* epf->remote or epf->local may be NULL if setting up a
5274 * forwarding failed. */
5276 struct ssh_rportfwd *rpf = epf->remote;
5277 struct Packet *pktout;
5280 * Cancel the port forwarding at the server
5283 if (ssh->version == 1) {
5285 * We cannot cancel listening ports on the
5286 * server side in SSH-1! There's no message
5287 * to support it. Instead, we simply remove
5288 * the rportfwd record from the local end
5289 * so that any connections the server tries
5290 * to make on it are rejected.
5293 pktout = ssh2_pkt_init(SSH2_MSG_GLOBAL_REQUEST);
5294 ssh2_pkt_addstring(pktout, "cancel-tcpip-forward");
5295 ssh2_pkt_addbool(pktout, 0);/* _don't_ want reply */
5297 ssh2_pkt_addstring(pktout, epf->saddr);
5298 } else if (conf_get_int(conf, CONF_rport_acceptall)) {
5299 /* XXX: rport_acceptall may not represent
5300 * what was used to open the original connection,
5301 * since it's reconfigurable. */
5302 ssh2_pkt_addstring(pktout, "");
5304 ssh2_pkt_addstring(pktout, "localhost");
5306 ssh2_pkt_adduint32(pktout, epf->sport);
5307 ssh2_pkt_send(ssh, pktout);
5310 del234(ssh->rportfwds, rpf);
5312 } else if (epf->local) {
5313 pfl_terminate(epf->local);
5316 delpos234(ssh->portfwds, i);
5318 i--; /* so we don't skip one in the list */
5322 * And finally, set up any new port forwardings (status==CREATE).
5324 for (i = 0; (epf = index234(ssh->portfwds, i)) != NULL; i++)
5325 if (epf->status == CREATE) {
5326 char *sportdesc, *dportdesc;
5327 sportdesc = dupprintf("%s%s%s%s%d%s",
5328 epf->saddr ? epf->saddr : "",
5329 epf->saddr ? ":" : "",
5330 epf->sserv ? epf->sserv : "",
5331 epf->sserv ? "(" : "",
5333 epf->sserv ? ")" : "");
5334 if (epf->type == 'D') {
5337 dportdesc = dupprintf("%s:%s%s%d%s",
5339 epf->dserv ? epf->dserv : "",
5340 epf->dserv ? "(" : "",
5342 epf->dserv ? ")" : "");
5345 if (epf->type == 'L') {
5346 char *err = pfl_listen(epf->daddr, epf->dport,
5347 epf->saddr, epf->sport,
5348 ssh, conf, &epf->local,
5349 epf->addressfamily);
5351 logeventf(ssh, "Local %sport %s forwarding to %s%s%s",
5352 epf->addressfamily == ADDRTYPE_IPV4 ? "IPv4 " :
5353 epf->addressfamily == ADDRTYPE_IPV6 ? "IPv6 " : "",
5354 sportdesc, dportdesc,
5355 err ? " failed: " : "", err ? err : "");
5358 } else if (epf->type == 'D') {
5359 char *err = pfl_listen(NULL, -1, epf->saddr, epf->sport,
5360 ssh, conf, &epf->local,
5361 epf->addressfamily);
5363 logeventf(ssh, "Local %sport %s SOCKS dynamic forwarding%s%s",
5364 epf->addressfamily == ADDRTYPE_IPV4 ? "IPv4 " :
5365 epf->addressfamily == ADDRTYPE_IPV6 ? "IPv6 " : "",
5367 err ? " failed: " : "", err ? err : "");
5372 struct ssh_rportfwd *pf;
5375 * Ensure the remote port forwardings tree exists.
5377 if (!ssh->rportfwds) {
5378 if (ssh->version == 1)
5379 ssh->rportfwds = newtree234(ssh_rportcmp_ssh1);
5381 ssh->rportfwds = newtree234(ssh_rportcmp_ssh2);
5384 pf = snew(struct ssh_rportfwd);
5385 pf->share_ctx = NULL;
5386 pf->dhost = dupstr(epf->daddr);
5387 pf->dport = epf->dport;
5389 pf->shost = dupstr(epf->saddr);
5390 } else if (conf_get_int(conf, CONF_rport_acceptall)) {
5391 pf->shost = dupstr("");
5393 pf->shost = dupstr("localhost");
5395 pf->sport = epf->sport;
5396 if (add234(ssh->rportfwds, pf) != pf) {
5397 logeventf(ssh, "Duplicate remote port forwarding to %s:%d",
5398 epf->daddr, epf->dport);
5401 logeventf(ssh, "Requesting remote port %s"
5402 " forward to %s", sportdesc, dportdesc);
5404 pf->sportdesc = sportdesc;
5409 if (ssh->version == 1) {
5410 send_packet(ssh, SSH1_CMSG_PORT_FORWARD_REQUEST,
5411 PKT_INT, epf->sport,
5412 PKT_STR, epf->daddr,
5413 PKT_INT, epf->dport,
5415 ssh_queue_handler(ssh, SSH1_SMSG_SUCCESS,
5417 ssh_rportfwd_succfail, pf);
5419 struct Packet *pktout;
5420 pktout = ssh2_pkt_init(SSH2_MSG_GLOBAL_REQUEST);
5421 ssh2_pkt_addstring(pktout, "tcpip-forward");
5422 ssh2_pkt_addbool(pktout, 1);/* want reply */
5423 ssh2_pkt_addstring(pktout, pf->shost);
5424 ssh2_pkt_adduint32(pktout, pf->sport);
5425 ssh2_pkt_send(ssh, pktout);
5427 ssh_queue_handler(ssh, SSH2_MSG_REQUEST_SUCCESS,
5428 SSH2_MSG_REQUEST_FAILURE,
5429 ssh_rportfwd_succfail, pf);
5438 static void ssh1_smsg_stdout_stderr_data(Ssh ssh, struct Packet *pktin)
5441 int stringlen, bufsize;
5443 ssh_pkt_getstring(pktin, &string, &stringlen);
5444 if (string == NULL) {
5445 bombout(("Incoming terminal data packet was badly formed"));
5449 bufsize = from_backend(ssh->frontend, pktin->type == SSH1_SMSG_STDERR_DATA,
5451 if (!ssh->v1_stdout_throttling && bufsize > SSH1_BUFFER_LIMIT) {
5452 ssh->v1_stdout_throttling = 1;
5453 ssh_throttle_conn(ssh, +1);
5457 static void ssh1_smsg_x11_open(Ssh ssh, struct Packet *pktin)
5459 /* Remote side is trying to open a channel to talk to our
5460 * X-Server. Give them back a local channel number. */
5461 struct ssh_channel *c;
5462 int remoteid = ssh_pkt_getuint32(pktin);
5464 logevent("Received X11 connect request");
5465 /* Refuse if X11 forwarding is disabled. */
5466 if (!ssh->X11_fwd_enabled) {
5467 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
5468 PKT_INT, remoteid, PKT_END);
5469 logevent("Rejected X11 connect request");
5471 c = snew(struct ssh_channel);
5474 c->u.x11.xconn = x11_init(ssh->x11authtree, c, NULL, -1);
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_X11; /* identify channel type */
5482 add234(ssh->channels, c);
5483 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
5484 PKT_INT, c->remoteid, PKT_INT,
5485 c->localid, PKT_END);
5486 logevent("Opened X11 forward channel");
5490 static void ssh1_smsg_agent_open(Ssh ssh, struct Packet *pktin)
5492 /* Remote side is trying to open a channel to talk to our
5493 * agent. Give them back a local channel number. */
5494 struct ssh_channel *c;
5495 int remoteid = ssh_pkt_getuint32(pktin);
5497 /* Refuse if agent forwarding is disabled. */
5498 if (!ssh->agentfwd_enabled) {
5499 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
5500 PKT_INT, remoteid, PKT_END);
5502 c = snew(struct ssh_channel);
5504 c->remoteid = remoteid;
5505 c->halfopen = FALSE;
5506 c->localid = alloc_channel_id(ssh);
5508 c->pending_eof = FALSE;
5509 c->throttling_conn = 0;
5510 c->type = CHAN_AGENT; /* identify channel type */
5511 c->u.a.lensofar = 0;
5512 c->u.a.message = NULL;
5513 c->u.a.outstanding_requests = 0;
5514 add234(ssh->channels, c);
5515 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
5516 PKT_INT, c->remoteid, PKT_INT, c->localid,
5521 static void ssh1_msg_port_open(Ssh ssh, struct Packet *pktin)
5523 /* Remote side is trying to open a channel to talk to a
5524 * forwarded port. Give them back a local channel number. */
5525 struct ssh_rportfwd pf, *pfp;
5531 remoteid = ssh_pkt_getuint32(pktin);
5532 ssh_pkt_getstring(pktin, &host, &hostsize);
5533 port = ssh_pkt_getuint32(pktin);
5535 pf.dhost = dupprintf("%.*s", hostsize, host);
5537 pfp = find234(ssh->rportfwds, &pf, NULL);
5540 logeventf(ssh, "Rejected remote port open request for %s:%d",
5542 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
5543 PKT_INT, remoteid, PKT_END);
5545 struct ssh_channel *c = snew(struct ssh_channel);
5548 logeventf(ssh, "Received remote port open request for %s:%d",
5550 err = pfd_connect(&c->u.pfd.pf, pf.dhost, port,
5551 c, ssh->conf, pfp->pfrec->addressfamily);
5553 logeventf(ssh, "Port open failed: %s", err);
5556 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
5557 PKT_INT, remoteid, PKT_END);
5559 c->remoteid = remoteid;
5560 c->halfopen = FALSE;
5561 c->localid = alloc_channel_id(ssh);
5563 c->pending_eof = FALSE;
5564 c->throttling_conn = 0;
5565 c->type = CHAN_SOCKDATA; /* identify channel type */
5566 add234(ssh->channels, c);
5567 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
5568 PKT_INT, c->remoteid, PKT_INT,
5569 c->localid, PKT_END);
5570 logevent("Forwarded port opened successfully");
5577 static void ssh1_msg_channel_open_confirmation(Ssh ssh, struct Packet *pktin)
5579 unsigned int remoteid = ssh_pkt_getuint32(pktin);
5580 unsigned int localid = ssh_pkt_getuint32(pktin);
5581 struct ssh_channel *c;
5583 c = find234(ssh->channels, &remoteid, ssh_channelfind);
5584 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
5585 c->remoteid = localid;
5586 c->halfopen = FALSE;
5587 c->type = CHAN_SOCKDATA;
5588 c->throttling_conn = 0;
5589 pfd_confirm(c->u.pfd.pf);
5592 if (c && c->pending_eof) {
5594 * We have a pending close on this channel,
5595 * which we decided on before the server acked
5596 * the channel open. So now we know the
5597 * remoteid, we can close it again.
5599 ssh_channel_try_eof(c);
5603 static void ssh1_msg_channel_open_failure(Ssh ssh, struct Packet *pktin)
5605 unsigned int remoteid = ssh_pkt_getuint32(pktin);
5606 struct ssh_channel *c;
5608 c = find234(ssh->channels, &remoteid, ssh_channelfind);
5609 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
5610 logevent("Forwarded connection refused by server");
5611 pfd_close(c->u.pfd.pf);
5612 del234(ssh->channels, c);
5617 static void ssh1_msg_channel_close(Ssh ssh, struct Packet *pktin)
5619 /* Remote side closes a channel. */
5620 unsigned i = ssh_pkt_getuint32(pktin);
5621 struct ssh_channel *c;
5622 c = find234(ssh->channels, &i, ssh_channelfind);
5623 if (c && !c->halfopen) {
5625 if (pktin->type == SSH1_MSG_CHANNEL_CLOSE &&
5626 !(c->closes & CLOSES_RCVD_EOF)) {
5628 * Received CHANNEL_CLOSE, which we translate into
5631 int send_close = FALSE;
5633 c->closes |= CLOSES_RCVD_EOF;
5638 x11_send_eof(c->u.x11.xconn);
5644 pfd_send_eof(c->u.pfd.pf);
5653 if (send_close && !(c->closes & CLOSES_SENT_EOF)) {
5654 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid,
5656 c->closes |= CLOSES_SENT_EOF;
5660 if (pktin->type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION &&
5661 !(c->closes & CLOSES_RCVD_CLOSE)) {
5663 if (!(c->closes & CLOSES_SENT_EOF)) {
5664 bombout(("Received CHANNEL_CLOSE_CONFIRMATION for channel %d"
5665 " for which we never sent CHANNEL_CLOSE\n", i));
5668 c->closes |= CLOSES_RCVD_CLOSE;
5671 if (!((CLOSES_SENT_EOF | CLOSES_RCVD_EOF) & ~c->closes) &&
5672 !(c->closes & CLOSES_SENT_CLOSE)) {
5673 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION,
5674 PKT_INT, c->remoteid, PKT_END);
5675 c->closes |= CLOSES_SENT_CLOSE;
5678 if (!((CLOSES_SENT_CLOSE | CLOSES_RCVD_CLOSE) & ~c->closes))
5679 ssh_channel_destroy(c);
5681 bombout(("Received CHANNEL_CLOSE%s for %s channel %d\n",
5682 pktin->type == SSH1_MSG_CHANNEL_CLOSE ? "" :
5683 "_CONFIRMATION", c ? "half-open" : "nonexistent",
5688 static void ssh1_msg_channel_data(Ssh ssh, struct Packet *pktin)
5690 /* Data sent down one of our channels. */
5691 int i = ssh_pkt_getuint32(pktin);
5694 struct ssh_channel *c;
5696 ssh_pkt_getstring(pktin, &p, &len);
5698 c = find234(ssh->channels, &i, ssh_channelfind);
5703 bufsize = x11_send(c->u.x11.xconn, p, len);
5706 bufsize = pfd_send(c->u.pfd.pf, p, len);
5709 /* Data for an agent message. Buffer it. */
5711 if (c->u.a.lensofar < 4) {
5712 unsigned int l = min(4 - c->u.a.lensofar, (unsigned)len);
5713 memcpy(c->u.a.msglen + c->u.a.lensofar, p,
5717 c->u.a.lensofar += l;
5719 if (c->u.a.lensofar == 4) {
5721 4 + GET_32BIT(c->u.a.msglen);
5722 c->u.a.message = snewn(c->u.a.totallen,
5724 memcpy(c->u.a.message, c->u.a.msglen, 4);
5726 if (c->u.a.lensofar >= 4 && len > 0) {
5728 min(c->u.a.totallen - c->u.a.lensofar,
5730 memcpy(c->u.a.message + c->u.a.lensofar, p,
5734 c->u.a.lensofar += l;
5736 if (c->u.a.lensofar == c->u.a.totallen) {
5739 c->u.a.outstanding_requests++;
5740 if (agent_query(c->u.a.message,
5743 ssh_agentf_callback, c))
5744 ssh_agentf_callback(c, reply, replylen);
5745 sfree(c->u.a.message);
5746 c->u.a.lensofar = 0;
5749 bufsize = 0; /* agent channels never back up */
5752 if (!c->throttling_conn && bufsize > SSH1_BUFFER_LIMIT) {
5753 c->throttling_conn = 1;
5754 ssh_throttle_conn(ssh, +1);
5759 static void ssh1_smsg_exit_status(Ssh ssh, struct Packet *pktin)
5761 ssh->exitcode = ssh_pkt_getuint32(pktin);
5762 logeventf(ssh, "Server sent command exit status %d", ssh->exitcode);
5763 send_packet(ssh, SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
5765 * In case `helpful' firewalls or proxies tack
5766 * extra human-readable text on the end of the
5767 * session which we might mistake for another
5768 * encrypted packet, we close the session once
5769 * we've sent EXIT_CONFIRMATION.
5771 ssh_disconnect(ssh, NULL, NULL, 0, TRUE);
5774 /* Helper function to deal with sending tty modes for REQUEST_PTY */
5775 static void ssh1_send_ttymode(void *data, char *mode, char *val)
5777 struct Packet *pktout = (struct Packet *)data;
5779 unsigned int arg = 0;
5780 while (strcmp(mode, ssh_ttymodes[i].mode) != 0) i++;
5781 if (i == lenof(ssh_ttymodes)) return;
5782 switch (ssh_ttymodes[i].type) {
5784 arg = ssh_tty_parse_specchar(val);
5787 arg = ssh_tty_parse_boolean(val);
5790 ssh2_pkt_addbyte(pktout, ssh_ttymodes[i].opcode);
5791 ssh2_pkt_addbyte(pktout, arg);
5794 int ssh_agent_forwarding_permitted(Ssh ssh)
5796 return conf_get_int(ssh->conf, CONF_agentfwd) && agent_exists();
5799 static void do_ssh1_connection(Ssh ssh, const unsigned char *in, int inlen,
5800 struct Packet *pktin)
5802 crBegin(ssh->do_ssh1_connection_crstate);
5804 ssh->packet_dispatch[SSH1_SMSG_STDOUT_DATA] =
5805 ssh->packet_dispatch[SSH1_SMSG_STDERR_DATA] =
5806 ssh1_smsg_stdout_stderr_data;
5808 ssh->packet_dispatch[SSH1_MSG_CHANNEL_OPEN_CONFIRMATION] =
5809 ssh1_msg_channel_open_confirmation;
5810 ssh->packet_dispatch[SSH1_MSG_CHANNEL_OPEN_FAILURE] =
5811 ssh1_msg_channel_open_failure;
5812 ssh->packet_dispatch[SSH1_MSG_CHANNEL_CLOSE] =
5813 ssh->packet_dispatch[SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION] =
5814 ssh1_msg_channel_close;
5815 ssh->packet_dispatch[SSH1_MSG_CHANNEL_DATA] = ssh1_msg_channel_data;
5816 ssh->packet_dispatch[SSH1_SMSG_EXIT_STATUS] = ssh1_smsg_exit_status;
5818 if (ssh_agent_forwarding_permitted(ssh)) {
5819 logevent("Requesting agent forwarding");
5820 send_packet(ssh, SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END);
5824 if (pktin->type != SSH1_SMSG_SUCCESS
5825 && pktin->type != SSH1_SMSG_FAILURE) {
5826 bombout(("Protocol confusion"));
5828 } else if (pktin->type == SSH1_SMSG_FAILURE) {
5829 logevent("Agent forwarding refused");
5831 logevent("Agent forwarding enabled");
5832 ssh->agentfwd_enabled = TRUE;
5833 ssh->packet_dispatch[SSH1_SMSG_AGENT_OPEN] = ssh1_smsg_agent_open;
5837 if (conf_get_int(ssh->conf, CONF_x11_forward)) {
5839 x11_setup_display(conf_get_str(ssh->conf, CONF_x11_display),
5841 if (!ssh->x11disp) {
5842 /* FIXME: return an error message from x11_setup_display */
5843 logevent("X11 forwarding not enabled: unable to"
5844 " initialise X display");
5846 ssh->x11auth = x11_invent_fake_auth
5847 (ssh->x11authtree, conf_get_int(ssh->conf, CONF_x11_auth));
5848 ssh->x11auth->disp = ssh->x11disp;
5850 logevent("Requesting X11 forwarding");
5851 if (ssh->v1_local_protoflags & SSH1_PROTOFLAG_SCREEN_NUMBER) {
5852 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
5853 PKT_STR, ssh->x11auth->protoname,
5854 PKT_STR, ssh->x11auth->datastring,
5855 PKT_INT, ssh->x11disp->screennum,
5858 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
5859 PKT_STR, ssh->x11auth->protoname,
5860 PKT_STR, ssh->x11auth->datastring,
5866 if (pktin->type != SSH1_SMSG_SUCCESS
5867 && pktin->type != SSH1_SMSG_FAILURE) {
5868 bombout(("Protocol confusion"));
5870 } else if (pktin->type == SSH1_SMSG_FAILURE) {
5871 logevent("X11 forwarding refused");
5873 logevent("X11 forwarding enabled");
5874 ssh->X11_fwd_enabled = TRUE;
5875 ssh->packet_dispatch[SSH1_SMSG_X11_OPEN] = ssh1_smsg_x11_open;
5880 ssh_setup_portfwd(ssh, ssh->conf);
5881 ssh->packet_dispatch[SSH1_MSG_PORT_OPEN] = ssh1_msg_port_open;
5883 if (!conf_get_int(ssh->conf, CONF_nopty)) {
5885 /* Unpick the terminal-speed string. */
5886 /* XXX perhaps we should allow no speeds to be sent. */
5887 ssh->ospeed = 38400; ssh->ispeed = 38400; /* last-resort defaults */
5888 sscanf(conf_get_str(ssh->conf, CONF_termspeed), "%d,%d", &ssh->ospeed, &ssh->ispeed);
5889 /* Send the pty request. */
5890 pkt = ssh1_pkt_init(SSH1_CMSG_REQUEST_PTY);
5891 ssh_pkt_addstring(pkt, conf_get_str(ssh->conf, CONF_termtype));
5892 ssh_pkt_adduint32(pkt, ssh->term_height);
5893 ssh_pkt_adduint32(pkt, ssh->term_width);
5894 ssh_pkt_adduint32(pkt, 0); /* width in pixels */
5895 ssh_pkt_adduint32(pkt, 0); /* height in pixels */
5896 parse_ttymodes(ssh, ssh1_send_ttymode, (void *)pkt);
5897 ssh_pkt_addbyte(pkt, SSH1_TTY_OP_ISPEED);
5898 ssh_pkt_adduint32(pkt, ssh->ispeed);
5899 ssh_pkt_addbyte(pkt, SSH1_TTY_OP_OSPEED);
5900 ssh_pkt_adduint32(pkt, ssh->ospeed);
5901 ssh_pkt_addbyte(pkt, SSH_TTY_OP_END);
5903 ssh->state = SSH_STATE_INTERMED;
5907 if (pktin->type != SSH1_SMSG_SUCCESS
5908 && pktin->type != SSH1_SMSG_FAILURE) {
5909 bombout(("Protocol confusion"));
5911 } else if (pktin->type == SSH1_SMSG_FAILURE) {
5912 c_write_str(ssh, "Server refused to allocate pty\r\n");
5913 ssh->editing = ssh->echoing = 1;
5915 logeventf(ssh, "Allocated pty (ospeed %dbps, ispeed %dbps)",
5916 ssh->ospeed, ssh->ispeed);
5917 ssh->got_pty = TRUE;
5920 ssh->editing = ssh->echoing = 1;
5923 if (conf_get_int(ssh->conf, CONF_compression)) {
5924 send_packet(ssh, SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END);
5928 if (pktin->type != SSH1_SMSG_SUCCESS
5929 && pktin->type != SSH1_SMSG_FAILURE) {
5930 bombout(("Protocol confusion"));
5932 } else if (pktin->type == SSH1_SMSG_FAILURE) {
5933 c_write_str(ssh, "Server refused to compress\r\n");
5935 logevent("Started compression");
5936 ssh->v1_compressing = TRUE;
5937 ssh->cs_comp_ctx = zlib_compress_init();
5938 logevent("Initialised zlib (RFC1950) compression");
5939 ssh->sc_comp_ctx = zlib_decompress_init();
5940 logevent("Initialised zlib (RFC1950) decompression");
5944 * Start the shell or command.
5946 * Special case: if the first-choice command is an SSH-2
5947 * subsystem (hence not usable here) and the second choice
5948 * exists, we fall straight back to that.
5951 char *cmd = conf_get_str(ssh->conf, CONF_remote_cmd);
5953 if (conf_get_int(ssh->conf, CONF_ssh_subsys) &&
5954 conf_get_str(ssh->conf, CONF_remote_cmd2)) {
5955 cmd = conf_get_str(ssh->conf, CONF_remote_cmd2);
5956 ssh->fallback_cmd = TRUE;
5959 send_packet(ssh, SSH1_CMSG_EXEC_CMD, PKT_STR, cmd, PKT_END);
5961 send_packet(ssh, SSH1_CMSG_EXEC_SHELL, PKT_END);
5962 logevent("Started session");
5965 ssh->state = SSH_STATE_SESSION;
5966 if (ssh->size_needed)
5967 ssh_size(ssh, ssh->term_width, ssh->term_height);
5968 if (ssh->eof_needed)
5969 ssh_special(ssh, TS_EOF);
5972 ldisc_echoedit_update(ssh->ldisc); /* cause ldisc to notice changes */
5974 ssh->channels = newtree234(ssh_channelcmp);
5978 * By this point, most incoming packets are already being
5979 * handled by the dispatch table, and we need only pay
5980 * attention to the unusual ones.
5985 if (pktin->type == SSH1_SMSG_SUCCESS) {
5986 /* may be from EXEC_SHELL on some servers */
5987 } else if (pktin->type == SSH1_SMSG_FAILURE) {
5988 /* may be from EXEC_SHELL on some servers
5989 * if no pty is available or in other odd cases. Ignore */
5991 bombout(("Strange packet received: type %d", pktin->type));
5996 int len = min(inlen, 512);
5997 send_packet(ssh, SSH1_CMSG_STDIN_DATA,
5998 PKT_INT, len, PKT_DATA, in, len,
6010 * Handle the top-level SSH-2 protocol.
6012 static void ssh1_msg_debug(Ssh ssh, struct Packet *pktin)
6017 ssh_pkt_getstring(pktin, &msg, &msglen);
6018 logeventf(ssh, "Remote debug message: %.*s", msglen, msg);
6021 static void ssh1_msg_disconnect(Ssh ssh, struct Packet *pktin)
6023 /* log reason code in disconnect message */
6027 ssh_pkt_getstring(pktin, &msg, &msglen);
6028 bombout(("Server sent disconnect message:\n\"%.*s\"", msglen, msg));
6031 static void ssh_msg_ignore(Ssh ssh, struct Packet *pktin)
6033 /* Do nothing, because we're ignoring it! Duhh. */
6036 static void ssh1_protocol_setup(Ssh ssh)
6041 * Most messages are handled by the coroutines.
6043 for (i = 0; i < 256; i++)
6044 ssh->packet_dispatch[i] = NULL;
6047 * These special message types we install handlers for.
6049 ssh->packet_dispatch[SSH1_MSG_DISCONNECT] = ssh1_msg_disconnect;
6050 ssh->packet_dispatch[SSH1_MSG_IGNORE] = ssh_msg_ignore;
6051 ssh->packet_dispatch[SSH1_MSG_DEBUG] = ssh1_msg_debug;
6054 static void ssh1_protocol(Ssh ssh, const void *vin, int inlen,
6055 struct Packet *pktin)
6057 const unsigned char *in = (const unsigned char *)vin;
6058 if (ssh->state == SSH_STATE_CLOSED)
6061 if (pktin && ssh->packet_dispatch[pktin->type]) {
6062 ssh->packet_dispatch[pktin->type](ssh, pktin);
6066 if (!ssh->protocol_initial_phase_done) {
6067 if (do_ssh1_login(ssh, in, inlen, pktin))
6068 ssh->protocol_initial_phase_done = TRUE;
6073 do_ssh1_connection(ssh, in, inlen, pktin);
6077 * Utility routines for decoding comma-separated strings in KEXINIT.
6079 static int first_in_commasep_string(char const *needle, char const *haystack,
6083 if (!needle || !haystack) /* protect against null pointers */
6085 needlen = strlen(needle);
6087 if (haylen >= needlen && /* haystack is long enough */
6088 !memcmp(needle, haystack, needlen) && /* initial match */
6089 (haylen == needlen || haystack[needlen] == ',')
6090 /* either , or EOS follows */
6096 static int in_commasep_string(char const *needle, char const *haystack,
6101 if (!needle || !haystack) /* protect against null pointers */
6104 * Is it at the start of the string?
6106 if (first_in_commasep_string(needle, haystack, haylen))
6109 * If not, search for the next comma and resume after that.
6110 * If no comma found, terminate.
6112 p = memchr(haystack, ',', haylen);
6114 /* + 1 to skip over comma */
6115 return in_commasep_string(needle, p + 1, haylen - (p + 1 - haystack));
6119 * Add a value to the comma-separated string at the end of the packet.
6121 static void ssh2_pkt_addstring_commasep(struct Packet *pkt, const char *data)
6123 if (pkt->length - pkt->savedpos > 0)
6124 ssh_pkt_addstring_str(pkt, ",");
6125 ssh_pkt_addstring_str(pkt, data);
6130 * SSH-2 key creation method.
6131 * (Currently assumes 2 lots of any hash are sufficient to generate
6132 * keys/IVs for any cipher/MAC. SSH2_MKKEY_ITERS documents this assumption.)
6134 #define SSH2_MKKEY_ITERS (2)
6135 static void ssh2_mkkey(Ssh ssh, Bignum K, unsigned char *H, char chr,
6136 unsigned char *keyspace)
6138 const struct ssh_hash *h = ssh->kex->hash;
6140 /* First hlen bytes. */
6142 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
6143 hash_mpint(h, s, K);
6144 h->bytes(s, H, h->hlen);
6145 h->bytes(s, &chr, 1);
6146 h->bytes(s, ssh->v2_session_id, ssh->v2_session_id_len);
6147 h->final(s, keyspace);
6148 /* Next hlen bytes. */
6150 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
6151 hash_mpint(h, s, K);
6152 h->bytes(s, H, h->hlen);
6153 h->bytes(s, keyspace, h->hlen);
6154 h->final(s, keyspace + h->hlen);
6158 * Structure for constructing KEXINIT algorithm lists.
6160 #define MAXKEXLIST 16
6161 struct kexinit_algorithm {
6165 const struct ssh_kex *kex;
6168 const struct ssh_signkey *hostkey;
6170 const struct ssh2_cipher *cipher;
6174 const struct ssh_mac *mac;
6177 const struct ssh_compress *comp;
6182 * Find a slot in a KEXINIT algorithm list to use for a new algorithm.
6183 * If the algorithm is already in the list, return a pointer to its
6184 * entry, otherwise return an entry from the end of the list.
6185 * This assumes that every time a particular name is passed in, it
6186 * comes from the same string constant. If this isn't true, this
6187 * function may need to be rewritten to use strcmp() instead.
6189 static struct kexinit_algorithm *ssh2_kexinit_addalg(struct kexinit_algorithm
6190 *list, const char *name)
6194 for (i = 0; i < MAXKEXLIST; i++)
6195 if (list[i].name == NULL || list[i].name == name) {
6196 list[i].name = name;
6199 assert(!"No space in KEXINIT list");
6203 * Handle the SSH-2 transport layer.
6205 static void do_ssh2_transport(Ssh ssh, const void *vin, int inlen,
6206 struct Packet *pktin)
6208 const unsigned char *in = (const unsigned char *)vin;
6210 KEXLIST_KEX, KEXLIST_HOSTKEY, KEXLIST_CSCIPHER, KEXLIST_SCCIPHER,
6211 KEXLIST_CSMAC, KEXLIST_SCMAC, KEXLIST_CSCOMP, KEXLIST_SCCOMP,
6214 const char * kexlist_descr[NKEXLIST] = {
6215 "key exchange algorithm", "host key algorithm",
6216 "client-to-server cipher", "server-to-client cipher",
6217 "client-to-server MAC", "server-to-client MAC",
6218 "client-to-server compression method",
6219 "server-to-client compression method" };
6220 struct do_ssh2_transport_state {
6222 int nbits, pbits, warn_kex, warn_cscipher, warn_sccipher;
6223 Bignum p, g, e, f, K;
6226 int kex_init_value, kex_reply_value;
6227 const struct ssh_mac **maclist;
6229 const struct ssh2_cipher *cscipher_tobe;
6230 const struct ssh2_cipher *sccipher_tobe;
6231 const struct ssh_mac *csmac_tobe;
6232 const struct ssh_mac *scmac_tobe;
6233 int csmac_etm_tobe, scmac_etm_tobe;
6234 const struct ssh_compress *cscomp_tobe;
6235 const struct ssh_compress *sccomp_tobe;
6236 char *hostkeydata, *sigdata, *rsakeydata, *keystr, *fingerprint;
6237 int hostkeylen, siglen, rsakeylen;
6238 void *hkey; /* actual host key */
6239 void *rsakey; /* for RSA kex */
6240 void *eckey; /* for ECDH kex */
6241 unsigned char exchange_hash[SSH2_KEX_MAX_HASH_LEN];
6242 int n_preferred_kex;
6243 const struct ssh_kexes *preferred_kex[KEX_MAX];
6244 int n_preferred_ciphers;
6245 const struct ssh2_ciphers *preferred_ciphers[CIPHER_MAX];
6246 const struct ssh_compress *preferred_comp;
6247 int userauth_succeeded; /* for delayed compression */
6248 int pending_compression;
6249 int got_session_id, activated_authconn;
6250 struct Packet *pktout;
6254 struct kexinit_algorithm kexlists[NKEXLIST][MAXKEXLIST];
6256 crState(do_ssh2_transport_state);
6258 assert(!ssh->bare_connection);
6262 s->cscipher_tobe = s->sccipher_tobe = NULL;
6263 s->csmac_tobe = s->scmac_tobe = NULL;
6264 s->cscomp_tobe = s->sccomp_tobe = NULL;
6266 s->got_session_id = s->activated_authconn = FALSE;
6267 s->userauth_succeeded = FALSE;
6268 s->pending_compression = FALSE;
6271 * Be prepared to work around the buggy MAC problem.
6273 if (ssh->remote_bugs & BUG_SSH2_HMAC)
6274 s->maclist = buggymacs, s->nmacs = lenof(buggymacs);
6276 s->maclist = macs, s->nmacs = lenof(macs);
6279 ssh->pkt_kctx = SSH2_PKTCTX_NOKEX;
6282 struct kexinit_algorithm *alg;
6285 * Set up the preferred key exchange. (NULL => warn below here)
6287 s->n_preferred_kex = 0;
6288 for (i = 0; i < KEX_MAX; i++) {
6289 switch (conf_get_int_int(ssh->conf, CONF_ssh_kexlist, i)) {
6291 s->preferred_kex[s->n_preferred_kex++] =
6292 &ssh_diffiehellman_gex;
6295 s->preferred_kex[s->n_preferred_kex++] =
6296 &ssh_diffiehellman_group14;
6299 s->preferred_kex[s->n_preferred_kex++] =
6300 &ssh_diffiehellman_group1;
6303 s->preferred_kex[s->n_preferred_kex++] =
6307 s->preferred_kex[s->n_preferred_kex++] =
6311 /* Flag for later. Don't bother if it's the last in
6313 if (i < KEX_MAX - 1) {
6314 s->preferred_kex[s->n_preferred_kex++] = NULL;
6321 * Set up the preferred ciphers. (NULL => warn below here)
6323 s->n_preferred_ciphers = 0;
6324 for (i = 0; i < CIPHER_MAX; i++) {
6325 switch (conf_get_int_int(ssh->conf, CONF_ssh_cipherlist, i)) {
6326 case CIPHER_BLOWFISH:
6327 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_blowfish;
6330 if (conf_get_int(ssh->conf, CONF_ssh2_des_cbc)) {
6331 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_des;
6335 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_3des;
6338 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_aes;
6340 case CIPHER_ARCFOUR:
6341 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_arcfour;
6343 case CIPHER_CHACHA20:
6344 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_ccp;
6347 /* Flag for later. Don't bother if it's the last in
6349 if (i < CIPHER_MAX - 1) {
6350 s->preferred_ciphers[s->n_preferred_ciphers++] = NULL;
6357 * Set up preferred compression.
6359 if (conf_get_int(ssh->conf, CONF_compression))
6360 s->preferred_comp = &ssh_zlib;
6362 s->preferred_comp = &ssh_comp_none;
6365 * Enable queueing of outgoing auth- or connection-layer
6366 * packets while we are in the middle of a key exchange.
6368 ssh->queueing = TRUE;
6371 * Flag that KEX is in progress.
6373 ssh->kex_in_progress = TRUE;
6375 for (i = 0; i < NKEXLIST; i++)
6376 for (j = 0; j < MAXKEXLIST; j++)
6377 s->kexlists[i][j].name = NULL;
6378 /* List key exchange algorithms. */
6380 for (i = 0; i < s->n_preferred_kex; i++) {
6381 const struct ssh_kexes *k = s->preferred_kex[i];
6382 if (!k) warn = TRUE;
6383 else for (j = 0; j < k->nkexes; j++) {
6384 alg = ssh2_kexinit_addalg(s->kexlists[KEXLIST_KEX],
6386 alg->u.kex.kex = k->list[j];
6387 alg->u.kex.warn = warn;
6390 /* List server host key algorithms. */
6391 if (!s->got_session_id) {
6393 * In the first key exchange, we list all the algorithms
6394 * we're prepared to cope with, but prefer those algorithms
6395 * for which we have a host key for this host.
6397 for (i = 0; i < lenof(hostkey_algs); i++) {
6398 if (have_ssh_host_key(ssh->savedhost, ssh->savedport,
6399 hostkey_algs[i]->keytype)) {
6400 alg = ssh2_kexinit_addalg(s->kexlists[KEXLIST_HOSTKEY],
6401 hostkey_algs[i]->name);
6402 alg->u.hostkey = hostkey_algs[i];
6405 for (i = 0; i < lenof(hostkey_algs); i++) {
6406 alg = ssh2_kexinit_addalg(s->kexlists[KEXLIST_HOSTKEY],
6407 hostkey_algs[i]->name);
6408 alg->u.hostkey = hostkey_algs[i];
6412 * In subsequent key exchanges, we list only the kex
6413 * algorithm that was selected in the first key exchange,
6414 * so that we keep getting the same host key and hence
6415 * don't have to interrupt the user's session to ask for
6419 alg = ssh2_kexinit_addalg(s->kexlists[KEXLIST_HOSTKEY],
6420 ssh->hostkey->name);
6421 alg->u.hostkey = ssh->hostkey;
6423 /* List encryption algorithms (client->server then server->client). */
6424 for (k = KEXLIST_CSCIPHER; k <= KEXLIST_SCCIPHER; k++) {
6426 for (i = 0; i < s->n_preferred_ciphers; i++) {
6427 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
6428 if (!c) warn = TRUE;
6429 else for (j = 0; j < c->nciphers; j++) {
6430 alg = ssh2_kexinit_addalg(s->kexlists[k],
6432 alg->u.cipher.cipher = c->list[j];
6433 alg->u.cipher.warn = warn;
6437 /* List MAC algorithms (client->server then server->client). */
6438 for (j = KEXLIST_CSMAC; j <= KEXLIST_SCMAC; j++) {
6439 for (i = 0; i < s->nmacs; i++) {
6440 alg = ssh2_kexinit_addalg(s->kexlists[j], s->maclist[i]->name);
6441 alg->u.mac.mac = s->maclist[i];
6442 alg->u.mac.etm = FALSE;
6444 for (i = 0; i < s->nmacs; i++)
6445 /* For each MAC, there may also be an ETM version,
6446 * which we list second. */
6447 if (s->maclist[i]->etm_name) {
6448 alg = ssh2_kexinit_addalg(s->kexlists[j],
6449 s->maclist[i]->etm_name);
6450 alg->u.mac.mac = s->maclist[i];
6451 alg->u.mac.etm = TRUE;
6454 /* List client->server compression algorithms,
6455 * then server->client compression algorithms. (We use the
6456 * same set twice.) */
6457 for (j = KEXLIST_CSCOMP; j <= KEXLIST_SCCOMP; j++) {
6458 assert(lenof(compressions) > 1);
6459 /* Prefer non-delayed versions */
6460 alg = ssh2_kexinit_addalg(s->kexlists[j], s->preferred_comp->name);
6461 alg->u.comp = s->preferred_comp;
6462 /* We don't even list delayed versions of algorithms until
6463 * they're allowed to be used, to avoid a race. See the end of
6465 if (s->userauth_succeeded && s->preferred_comp->delayed_name) {
6466 alg = ssh2_kexinit_addalg(s->kexlists[j],
6467 s->preferred_comp->delayed_name);
6468 alg->u.comp = s->preferred_comp;
6470 for (i = 0; i < lenof(compressions); i++) {
6471 const struct ssh_compress *c = compressions[i];
6472 alg = ssh2_kexinit_addalg(s->kexlists[j], c->name);
6474 if (s->userauth_succeeded && c->delayed_name) {
6475 alg = ssh2_kexinit_addalg(s->kexlists[j], c->delayed_name);
6481 * Construct and send our key exchange packet.
6483 s->pktout = ssh2_pkt_init(SSH2_MSG_KEXINIT);
6484 for (i = 0; i < 16; i++)
6485 ssh2_pkt_addbyte(s->pktout, (unsigned char) random_byte());
6486 for (i = 0; i < NKEXLIST; i++) {
6487 ssh2_pkt_addstring_start(s->pktout);
6488 for (j = 0; j < MAXKEXLIST; j++) {
6489 if (s->kexlists[i][j].name == NULL) break;
6490 ssh2_pkt_addstring_commasep(s->pktout, s->kexlists[i][j].name);
6493 /* List client->server languages. Empty list. */
6494 ssh2_pkt_addstring_start(s->pktout);
6495 /* List server->client languages. Empty list. */
6496 ssh2_pkt_addstring_start(s->pktout);
6497 /* First KEX packet does _not_ follow, because we're not that brave. */
6498 ssh2_pkt_addbool(s->pktout, FALSE);
6500 ssh2_pkt_adduint32(s->pktout, 0);
6503 s->our_kexinitlen = s->pktout->length - 5;
6504 s->our_kexinit = snewn(s->our_kexinitlen, unsigned char);
6505 memcpy(s->our_kexinit, s->pktout->data + 5, s->our_kexinitlen);
6507 ssh2_pkt_send_noqueue(ssh, s->pktout);
6510 crWaitUntilV(pktin);
6513 * Now examine the other side's KEXINIT to see what we're up
6520 if (pktin->type != SSH2_MSG_KEXINIT) {
6521 bombout(("expected key exchange packet from server"));
6525 ssh->hostkey = NULL;
6526 s->cscipher_tobe = NULL;
6527 s->sccipher_tobe = NULL;
6528 s->csmac_tobe = NULL;
6529 s->scmac_tobe = NULL;
6530 s->cscomp_tobe = NULL;
6531 s->sccomp_tobe = NULL;
6532 s->warn_kex = s->warn_cscipher = s->warn_sccipher = FALSE;
6534 pktin->savedpos += 16; /* skip garbage cookie */
6537 for (i = 0; i < NKEXLIST; i++) {
6538 ssh_pkt_getstring(pktin, &str, &len);
6540 bombout(("KEXINIT packet was incomplete"));
6543 for (j = 0; j < MAXKEXLIST; j++) {
6544 struct kexinit_algorithm *alg = &s->kexlists[i][j];
6545 if (alg->name == NULL) break;
6546 if (in_commasep_string(alg->name, str, len)) {
6547 /* We've found a matching algorithm. */
6548 if (i == KEXLIST_KEX || i == KEXLIST_HOSTKEY) {
6549 /* Check if we might need to ignore first kex pkt */
6551 !first_in_commasep_string(alg->name, str, len))
6554 if (i == KEXLIST_KEX) {
6555 ssh->kex = alg->u.kex.kex;
6556 s->warn_kex = alg->u.kex.warn;
6557 } else if (i == KEXLIST_HOSTKEY) {
6558 ssh->hostkey = alg->u.hostkey;
6559 } else if (i == KEXLIST_CSCIPHER) {
6560 s->cscipher_tobe = alg->u.cipher.cipher;
6561 s->warn_cscipher = alg->u.cipher.warn;
6562 } else if (i == KEXLIST_SCCIPHER) {
6563 s->sccipher_tobe = alg->u.cipher.cipher;
6564 s->warn_sccipher = alg->u.cipher.warn;
6565 } else if (i == KEXLIST_CSMAC) {
6566 s->csmac_tobe = alg->u.mac.mac;
6567 s->csmac_etm_tobe = alg->u.mac.etm;
6568 } else if (i == KEXLIST_SCMAC) {
6569 s->scmac_tobe = alg->u.mac.mac;
6570 s->scmac_etm_tobe = alg->u.mac.etm;
6571 } else if (i == KEXLIST_CSCOMP) {
6572 s->cscomp_tobe = alg->u.comp;
6573 } else if (i == KEXLIST_SCCOMP) {
6574 s->sccomp_tobe = alg->u.comp;
6578 if ((i == KEXLIST_CSCOMP || i == KEXLIST_SCCOMP) &&
6579 in_commasep_string(alg->u.comp->delayed_name, str, len))
6580 s->pending_compression = TRUE; /* try this later */
6582 bombout(("Couldn't agree a %s ((available: %.*s)",
6583 kexlist_descr[i], len, str));
6588 /* If the cipher over-rides the mac, then pick it */
6589 if (s->cscipher_tobe && s->cscipher_tobe->required_mac) {
6590 s->csmac_tobe = s->cscipher_tobe->required_mac;
6591 s->csmac_etm_tobe = !!(s->csmac_tobe->etm_name);
6593 if (s->sccipher_tobe && s->sccipher_tobe->required_mac) {
6594 s->scmac_tobe = s->sccipher_tobe->required_mac;
6595 s->scmac_etm_tobe = !!(s->scmac_tobe->etm_name);
6598 if (s->pending_compression) {
6599 logevent("Server supports delayed compression; "
6600 "will try this later");
6602 ssh_pkt_getstring(pktin, &str, &len); /* client->server language */
6603 ssh_pkt_getstring(pktin, &str, &len); /* server->client language */
6604 s->ignorepkt = ssh2_pkt_getbool(pktin) && !s->guessok;
6606 ssh->exhash = ssh->kex->hash->init();
6607 hash_string(ssh->kex->hash, ssh->exhash, ssh->v_c, strlen(ssh->v_c));
6608 hash_string(ssh->kex->hash, ssh->exhash, ssh->v_s, strlen(ssh->v_s));
6609 hash_string(ssh->kex->hash, ssh->exhash,
6610 s->our_kexinit, s->our_kexinitlen);
6611 sfree(s->our_kexinit);
6612 /* Include the type byte in the hash of server's KEXINIT */
6613 hash_string(ssh->kex->hash, ssh->exhash,
6614 pktin->body - 1, pktin->length + 1);
6617 ssh_set_frozen(ssh, 1);
6618 s->dlgret = askalg(ssh->frontend, "key-exchange algorithm",
6620 ssh_dialog_callback, ssh);
6621 if (s->dlgret < 0) {
6625 bombout(("Unexpected data from server while"
6626 " waiting for user response"));
6629 } while (pktin || inlen > 0);
6630 s->dlgret = ssh->user_response;
6632 ssh_set_frozen(ssh, 0);
6633 if (s->dlgret == 0) {
6634 ssh_disconnect(ssh, "User aborted at kex warning", NULL,
6640 if (s->warn_cscipher) {
6641 ssh_set_frozen(ssh, 1);
6642 s->dlgret = askalg(ssh->frontend,
6643 "client-to-server cipher",
6644 s->cscipher_tobe->name,
6645 ssh_dialog_callback, ssh);
6646 if (s->dlgret < 0) {
6650 bombout(("Unexpected data from server while"
6651 " waiting for user response"));
6654 } while (pktin || inlen > 0);
6655 s->dlgret = ssh->user_response;
6657 ssh_set_frozen(ssh, 0);
6658 if (s->dlgret == 0) {
6659 ssh_disconnect(ssh, "User aborted at cipher warning", NULL,
6665 if (s->warn_sccipher) {
6666 ssh_set_frozen(ssh, 1);
6667 s->dlgret = askalg(ssh->frontend,
6668 "server-to-client cipher",
6669 s->sccipher_tobe->name,
6670 ssh_dialog_callback, ssh);
6671 if (s->dlgret < 0) {
6675 bombout(("Unexpected data from server while"
6676 " waiting for user response"));
6679 } while (pktin || inlen > 0);
6680 s->dlgret = ssh->user_response;
6682 ssh_set_frozen(ssh, 0);
6683 if (s->dlgret == 0) {
6684 ssh_disconnect(ssh, "User aborted at cipher warning", NULL,
6690 if (s->ignorepkt) /* first_kex_packet_follows */
6691 crWaitUntilV(pktin); /* Ignore packet */
6694 if (ssh->kex->main_type == KEXTYPE_DH) {
6696 * Work out the number of bits of key we will need from the
6697 * key exchange. We start with the maximum key length of
6703 csbits = s->cscipher_tobe->keylen;
6704 scbits = s->sccipher_tobe->keylen;
6705 s->nbits = (csbits > scbits ? csbits : scbits);
6707 /* The keys only have hlen-bit entropy, since they're based on
6708 * a hash. So cap the key size at hlen bits. */
6709 if (s->nbits > ssh->kex->hash->hlen * 8)
6710 s->nbits = ssh->kex->hash->hlen * 8;
6713 * If we're doing Diffie-Hellman group exchange, start by
6714 * requesting a group.
6716 if (dh_is_gex(ssh->kex)) {
6717 logevent("Doing Diffie-Hellman group exchange");
6718 ssh->pkt_kctx = SSH2_PKTCTX_DHGEX;
6720 * Work out how big a DH group we will need to allow that
6723 s->pbits = 512 << ((s->nbits - 1) / 64);
6724 if (s->pbits < DH_MIN_SIZE)
6725 s->pbits = DH_MIN_SIZE;
6726 if (s->pbits > DH_MAX_SIZE)
6727 s->pbits = DH_MAX_SIZE;
6728 if ((ssh->remote_bugs & BUG_SSH2_OLDGEX)) {
6729 s->pktout = ssh2_pkt_init(SSH2_MSG_KEX_DH_GEX_REQUEST_OLD);
6730 ssh2_pkt_adduint32(s->pktout, s->pbits);
6732 s->pktout = ssh2_pkt_init(SSH2_MSG_KEX_DH_GEX_REQUEST);
6733 ssh2_pkt_adduint32(s->pktout, DH_MIN_SIZE);
6734 ssh2_pkt_adduint32(s->pktout, s->pbits);
6735 ssh2_pkt_adduint32(s->pktout, DH_MAX_SIZE);
6737 ssh2_pkt_send_noqueue(ssh, s->pktout);
6739 crWaitUntilV(pktin);
6740 if (pktin->type != SSH2_MSG_KEX_DH_GEX_GROUP) {
6741 bombout(("expected key exchange group packet from server"));
6744 s->p = ssh2_pkt_getmp(pktin);
6745 s->g = ssh2_pkt_getmp(pktin);
6746 if (!s->p || !s->g) {
6747 bombout(("unable to read mp-ints from incoming group packet"));
6750 ssh->kex_ctx = dh_setup_gex(s->p, s->g);
6751 s->kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT;
6752 s->kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY;
6754 ssh->pkt_kctx = SSH2_PKTCTX_DHGROUP;
6755 ssh->kex_ctx = dh_setup_group(ssh->kex);
6756 s->kex_init_value = SSH2_MSG_KEXDH_INIT;
6757 s->kex_reply_value = SSH2_MSG_KEXDH_REPLY;
6758 logeventf(ssh, "Using Diffie-Hellman with standard group \"%s\"",
6759 ssh->kex->groupname);
6762 logeventf(ssh, "Doing Diffie-Hellman key exchange with hash %s",
6763 ssh->kex->hash->text_name);
6765 * Now generate and send e for Diffie-Hellman.
6767 set_busy_status(ssh->frontend, BUSY_CPU); /* this can take a while */
6768 s->e = dh_create_e(ssh->kex_ctx, s->nbits * 2);
6769 s->pktout = ssh2_pkt_init(s->kex_init_value);
6770 ssh2_pkt_addmp(s->pktout, s->e);
6771 ssh2_pkt_send_noqueue(ssh, s->pktout);
6773 set_busy_status(ssh->frontend, BUSY_WAITING); /* wait for server */
6774 crWaitUntilV(pktin);
6775 if (pktin->type != s->kex_reply_value) {
6776 bombout(("expected key exchange reply packet from server"));
6779 set_busy_status(ssh->frontend, BUSY_CPU); /* cogitate */
6780 ssh_pkt_getstring(pktin, &s->hostkeydata, &s->hostkeylen);
6781 if (!s->hostkeydata) {
6782 bombout(("unable to parse key exchange reply packet"));
6785 s->hkey = ssh->hostkey->newkey(ssh->hostkey,
6786 s->hostkeydata, s->hostkeylen);
6787 s->f = ssh2_pkt_getmp(pktin);
6789 bombout(("unable to parse key exchange reply packet"));
6792 ssh_pkt_getstring(pktin, &s->sigdata, &s->siglen);
6794 bombout(("unable to parse key exchange reply packet"));
6799 const char *err = dh_validate_f(ssh->kex_ctx, s->f);
6801 bombout(("key exchange reply failed validation: %s", err));
6805 s->K = dh_find_K(ssh->kex_ctx, s->f);
6807 /* We assume everything from now on will be quick, and it might
6808 * involve user interaction. */
6809 set_busy_status(ssh->frontend, BUSY_NOT);
6811 hash_string(ssh->kex->hash, ssh->exhash, s->hostkeydata, s->hostkeylen);
6812 if (dh_is_gex(ssh->kex)) {
6813 if (!(ssh->remote_bugs & BUG_SSH2_OLDGEX))
6814 hash_uint32(ssh->kex->hash, ssh->exhash, DH_MIN_SIZE);
6815 hash_uint32(ssh->kex->hash, ssh->exhash, s->pbits);
6816 if (!(ssh->remote_bugs & BUG_SSH2_OLDGEX))
6817 hash_uint32(ssh->kex->hash, ssh->exhash, DH_MAX_SIZE);
6818 hash_mpint(ssh->kex->hash, ssh->exhash, s->p);
6819 hash_mpint(ssh->kex->hash, ssh->exhash, s->g);
6821 hash_mpint(ssh->kex->hash, ssh->exhash, s->e);
6822 hash_mpint(ssh->kex->hash, ssh->exhash, s->f);
6824 dh_cleanup(ssh->kex_ctx);
6826 if (dh_is_gex(ssh->kex)) {
6830 } else if (ssh->kex->main_type == KEXTYPE_ECDH) {
6832 logeventf(ssh, "Doing ECDH key exchange with curve %s and hash %s",
6833 ssh_ecdhkex_curve_textname(ssh->kex),
6834 ssh->kex->hash->text_name);
6835 ssh->pkt_kctx = SSH2_PKTCTX_ECDHKEX;
6837 s->eckey = ssh_ecdhkex_newkey(ssh->kex);
6839 bombout(("Unable to generate key for ECDH"));
6845 int publicPointLength;
6846 publicPoint = ssh_ecdhkex_getpublic(s->eckey, &publicPointLength);
6848 ssh_ecdhkex_freekey(s->eckey);
6849 bombout(("Unable to encode public key for ECDH"));
6852 s->pktout = ssh2_pkt_init(SSH2_MSG_KEX_ECDH_INIT);
6853 ssh2_pkt_addstring_start(s->pktout);
6854 ssh2_pkt_addstring_data(s->pktout, publicPoint, publicPointLength);
6858 ssh2_pkt_send_noqueue(ssh, s->pktout);
6860 crWaitUntilV(pktin);
6861 if (pktin->type != SSH2_MSG_KEX_ECDH_REPLY) {
6862 ssh_ecdhkex_freekey(s->eckey);
6863 bombout(("expected ECDH reply packet from server"));
6867 ssh_pkt_getstring(pktin, &s->hostkeydata, &s->hostkeylen);
6868 if (!s->hostkeydata) {
6869 bombout(("unable to parse ECDH reply packet"));
6872 hash_string(ssh->kex->hash, ssh->exhash, s->hostkeydata, s->hostkeylen);
6873 s->hkey = ssh->hostkey->newkey(ssh->hostkey,
6874 s->hostkeydata, s->hostkeylen);
6878 int publicPointLength;
6879 publicPoint = ssh_ecdhkex_getpublic(s->eckey, &publicPointLength);
6881 ssh_ecdhkex_freekey(s->eckey);
6882 bombout(("Unable to encode public key for ECDH hash"));
6885 hash_string(ssh->kex->hash, ssh->exhash,
6886 publicPoint, publicPointLength);
6893 ssh_pkt_getstring(pktin, &keydata, &keylen);
6895 bombout(("unable to parse ECDH reply packet"));
6898 hash_string(ssh->kex->hash, ssh->exhash, keydata, keylen);
6899 s->K = ssh_ecdhkex_getkey(s->eckey, keydata, keylen);
6901 ssh_ecdhkex_freekey(s->eckey);
6902 bombout(("point received in ECDH was not valid"));
6907 ssh_pkt_getstring(pktin, &s->sigdata, &s->siglen);
6909 bombout(("unable to parse key exchange reply packet"));
6913 ssh_ecdhkex_freekey(s->eckey);
6915 logeventf(ssh, "Doing RSA key exchange with hash %s",
6916 ssh->kex->hash->text_name);
6917 ssh->pkt_kctx = SSH2_PKTCTX_RSAKEX;
6919 * RSA key exchange. First expect a KEXRSA_PUBKEY packet
6922 crWaitUntilV(pktin);
6923 if (pktin->type != SSH2_MSG_KEXRSA_PUBKEY) {
6924 bombout(("expected RSA public key packet from server"));
6928 ssh_pkt_getstring(pktin, &s->hostkeydata, &s->hostkeylen);
6929 if (!s->hostkeydata) {
6930 bombout(("unable to parse RSA public key packet"));
6933 hash_string(ssh->kex->hash, ssh->exhash,
6934 s->hostkeydata, s->hostkeylen);
6935 s->hkey = ssh->hostkey->newkey(ssh->hostkey,
6936 s->hostkeydata, s->hostkeylen);
6940 ssh_pkt_getstring(pktin, &keydata, &s->rsakeylen);
6942 bombout(("unable to parse RSA public key packet"));
6945 s->rsakeydata = snewn(s->rsakeylen, char);
6946 memcpy(s->rsakeydata, keydata, s->rsakeylen);
6949 s->rsakey = ssh_rsakex_newkey(s->rsakeydata, s->rsakeylen);
6951 sfree(s->rsakeydata);
6952 bombout(("unable to parse RSA public key from server"));
6956 hash_string(ssh->kex->hash, ssh->exhash, s->rsakeydata, s->rsakeylen);
6959 * Next, set up a shared secret K, of precisely KLEN -
6960 * 2*HLEN - 49 bits, where KLEN is the bit length of the
6961 * RSA key modulus and HLEN is the bit length of the hash
6965 int klen = ssh_rsakex_klen(s->rsakey);
6966 int nbits = klen - (2*ssh->kex->hash->hlen*8 + 49);
6968 unsigned char *kstr1, *kstr2, *outstr;
6969 int kstr1len, kstr2len, outstrlen;
6971 s->K = bn_power_2(nbits - 1);
6973 for (i = 0; i < nbits; i++) {
6975 byte = random_byte();
6977 bignum_set_bit(s->K, i, (byte >> (i & 7)) & 1);
6981 * Encode this as an mpint.
6983 kstr1 = ssh2_mpint_fmt(s->K, &kstr1len);
6984 kstr2 = snewn(kstr2len = 4 + kstr1len, unsigned char);
6985 PUT_32BIT(kstr2, kstr1len);
6986 memcpy(kstr2 + 4, kstr1, kstr1len);
6989 * Encrypt it with the given RSA key.
6991 outstrlen = (klen + 7) / 8;
6992 outstr = snewn(outstrlen, unsigned char);
6993 ssh_rsakex_encrypt(ssh->kex->hash, kstr2, kstr2len,
6994 outstr, outstrlen, s->rsakey);
6997 * And send it off in a return packet.
6999 s->pktout = ssh2_pkt_init(SSH2_MSG_KEXRSA_SECRET);
7000 ssh2_pkt_addstring_start(s->pktout);
7001 ssh2_pkt_addstring_data(s->pktout, (char *)outstr, outstrlen);
7002 ssh2_pkt_send_noqueue(ssh, s->pktout);
7004 hash_string(ssh->kex->hash, ssh->exhash, outstr, outstrlen);
7011 ssh_rsakex_freekey(s->rsakey);
7013 crWaitUntilV(pktin);
7014 if (pktin->type != SSH2_MSG_KEXRSA_DONE) {
7015 sfree(s->rsakeydata);
7016 bombout(("expected signature packet from server"));
7020 ssh_pkt_getstring(pktin, &s->sigdata, &s->siglen);
7022 bombout(("unable to parse signature packet"));
7026 sfree(s->rsakeydata);
7029 hash_mpint(ssh->kex->hash, ssh->exhash, s->K);
7030 assert(ssh->kex->hash->hlen <= sizeof(s->exchange_hash));
7031 ssh->kex->hash->final(ssh->exhash, s->exchange_hash);
7033 ssh->kex_ctx = NULL;
7036 debug(("Exchange hash is:\n"));
7037 dmemdump(s->exchange_hash, ssh->kex->hash->hlen);
7041 !ssh->hostkey->verifysig(s->hkey, s->sigdata, s->siglen,
7042 (char *)s->exchange_hash,
7043 ssh->kex->hash->hlen)) {
7044 bombout(("Server's host key did not match the signature supplied"));
7048 s->keystr = ssh->hostkey->fmtkey(s->hkey);
7049 if (!s->got_session_id) {
7051 * Authenticate remote host: verify host key. (We've already
7052 * checked the signature of the exchange hash.)
7054 s->fingerprint = ssh2_fingerprint(ssh->hostkey, s->hkey);
7055 logevent("Host key fingerprint is:");
7056 logevent(s->fingerprint);
7057 /* First check against manually configured host keys. */
7058 s->dlgret = verify_ssh_manual_host_key(ssh, s->fingerprint,
7059 ssh->hostkey, s->hkey);
7060 if (s->dlgret == 0) { /* did not match */
7061 bombout(("Host key did not appear in manually configured list"));
7063 } else if (s->dlgret < 0) { /* none configured; use standard handling */
7064 ssh_set_frozen(ssh, 1);
7065 s->dlgret = verify_ssh_host_key(ssh->frontend,
7066 ssh->savedhost, ssh->savedport,
7067 ssh->hostkey->keytype, s->keystr,
7069 ssh_dialog_callback, ssh);
7070 if (s->dlgret < 0) {
7074 bombout(("Unexpected data from server while waiting"
7075 " for user host key response"));
7078 } while (pktin || inlen > 0);
7079 s->dlgret = ssh->user_response;
7081 ssh_set_frozen(ssh, 0);
7082 if (s->dlgret == 0) {
7083 ssh_disconnect(ssh, "Aborted at host key verification", NULL,
7088 sfree(s->fingerprint);
7090 * Save this host key, to check against the one presented in
7091 * subsequent rekeys.
7093 ssh->hostkey_str = s->keystr;
7096 * In a rekey, we never present an interactive host key
7097 * verification request to the user. Instead, we simply
7098 * enforce that the key we're seeing this time is identical to
7099 * the one we saw before.
7101 if (strcmp(ssh->hostkey_str, s->keystr)) {
7102 bombout(("Host key was different in repeat key exchange"));
7107 ssh->hostkey->freekey(s->hkey);
7110 * The exchange hash from the very first key exchange is also
7111 * the session id, used in session key construction and
7114 if (!s->got_session_id) {
7115 assert(sizeof(s->exchange_hash) <= sizeof(ssh->v2_session_id));
7116 memcpy(ssh->v2_session_id, s->exchange_hash,
7117 sizeof(s->exchange_hash));
7118 ssh->v2_session_id_len = ssh->kex->hash->hlen;
7119 assert(ssh->v2_session_id_len <= sizeof(ssh->v2_session_id));
7120 s->got_session_id = TRUE;
7124 * Send SSH2_MSG_NEWKEYS.
7126 s->pktout = ssh2_pkt_init(SSH2_MSG_NEWKEYS);
7127 ssh2_pkt_send_noqueue(ssh, s->pktout);
7128 ssh->outgoing_data_size = 0; /* start counting from here */
7131 * We've sent client NEWKEYS, so create and initialise
7132 * client-to-server session keys.
7134 if (ssh->cs_cipher_ctx)
7135 ssh->cscipher->free_context(ssh->cs_cipher_ctx);
7136 ssh->cscipher = s->cscipher_tobe;
7137 ssh->cs_cipher_ctx = ssh->cscipher->make_context();
7139 if (ssh->cs_mac_ctx)
7140 ssh->csmac->free_context(ssh->cs_mac_ctx);
7141 ssh->csmac = s->csmac_tobe;
7142 ssh->csmac_etm = s->csmac_etm_tobe;
7143 ssh->cs_mac_ctx = ssh->csmac->make_context(ssh->cs_cipher_ctx);
7145 if (ssh->cs_comp_ctx)
7146 ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
7147 ssh->cscomp = s->cscomp_tobe;
7148 ssh->cs_comp_ctx = ssh->cscomp->compress_init();
7151 * Set IVs on client-to-server keys. Here we use the exchange
7152 * hash from the _first_ key exchange.
7155 unsigned char keyspace[SSH2_KEX_MAX_HASH_LEN * SSH2_MKKEY_ITERS];
7156 assert(sizeof(keyspace) >= ssh->kex->hash->hlen * SSH2_MKKEY_ITERS);
7157 ssh2_mkkey(ssh,s->K,s->exchange_hash,'C',keyspace);
7158 assert((ssh->cscipher->keylen+7) / 8 <=
7159 ssh->kex->hash->hlen * SSH2_MKKEY_ITERS);
7160 ssh->cscipher->setkey(ssh->cs_cipher_ctx, keyspace);
7161 ssh2_mkkey(ssh,s->K,s->exchange_hash,'A',keyspace);
7162 assert(ssh->cscipher->blksize <=
7163 ssh->kex->hash->hlen * SSH2_MKKEY_ITERS);
7164 ssh->cscipher->setiv(ssh->cs_cipher_ctx, keyspace);
7165 ssh2_mkkey(ssh,s->K,s->exchange_hash,'E',keyspace);
7166 assert(ssh->csmac->len <=
7167 ssh->kex->hash->hlen * SSH2_MKKEY_ITERS);
7168 ssh->csmac->setkey(ssh->cs_mac_ctx, keyspace);
7169 smemclr(keyspace, sizeof(keyspace));
7172 logeventf(ssh, "Initialised %.200s client->server encryption",
7173 ssh->cscipher->text_name);
7174 logeventf(ssh, "Initialised %.200s client->server MAC algorithm%s%s",
7175 ssh->csmac->text_name,
7176 ssh->csmac_etm ? " (in ETM mode)" : "",
7177 ssh->cscipher->required_mac ? " (required by cipher)" : "");
7178 if (ssh->cscomp->text_name)
7179 logeventf(ssh, "Initialised %s compression",
7180 ssh->cscomp->text_name);
7183 * Now our end of the key exchange is complete, we can send all
7184 * our queued higher-layer packets.
7186 ssh->queueing = FALSE;
7187 ssh2_pkt_queuesend(ssh);
7190 * Expect SSH2_MSG_NEWKEYS from server.
7192 crWaitUntilV(pktin);
7193 if (pktin->type != SSH2_MSG_NEWKEYS) {
7194 bombout(("expected new-keys packet from server"));
7197 ssh->incoming_data_size = 0; /* start counting from here */
7200 * We've seen server NEWKEYS, so create and initialise
7201 * server-to-client session keys.
7203 if (ssh->sc_cipher_ctx)
7204 ssh->sccipher->free_context(ssh->sc_cipher_ctx);
7205 ssh->sccipher = s->sccipher_tobe;
7206 ssh->sc_cipher_ctx = ssh->sccipher->make_context();
7208 if (ssh->sc_mac_ctx)
7209 ssh->scmac->free_context(ssh->sc_mac_ctx);
7210 ssh->scmac = s->scmac_tobe;
7211 ssh->scmac_etm = s->scmac_etm_tobe;
7212 ssh->sc_mac_ctx = ssh->scmac->make_context(ssh->sc_cipher_ctx);
7214 if (ssh->sc_comp_ctx)
7215 ssh->sccomp->decompress_cleanup(ssh->sc_comp_ctx);
7216 ssh->sccomp = s->sccomp_tobe;
7217 ssh->sc_comp_ctx = ssh->sccomp->decompress_init();
7220 * Set IVs on server-to-client keys. Here we use the exchange
7221 * hash from the _first_ key exchange.
7224 unsigned char keyspace[SSH2_KEX_MAX_HASH_LEN * SSH2_MKKEY_ITERS];
7225 assert(sizeof(keyspace) >= ssh->kex->hash->hlen * SSH2_MKKEY_ITERS);
7226 ssh2_mkkey(ssh,s->K,s->exchange_hash,'D',keyspace);
7227 assert((ssh->sccipher->keylen+7) / 8 <=
7228 ssh->kex->hash->hlen * SSH2_MKKEY_ITERS);
7229 ssh->sccipher->setkey(ssh->sc_cipher_ctx, keyspace);
7230 ssh2_mkkey(ssh,s->K,s->exchange_hash,'B',keyspace);
7231 assert(ssh->sccipher->blksize <=
7232 ssh->kex->hash->hlen * SSH2_MKKEY_ITERS);
7233 ssh->sccipher->setiv(ssh->sc_cipher_ctx, keyspace);
7234 ssh2_mkkey(ssh,s->K,s->exchange_hash,'F',keyspace);
7235 assert(ssh->scmac->len <=
7236 ssh->kex->hash->hlen * SSH2_MKKEY_ITERS);
7237 ssh->scmac->setkey(ssh->sc_mac_ctx, keyspace);
7238 smemclr(keyspace, sizeof(keyspace));
7240 logeventf(ssh, "Initialised %.200s server->client encryption",
7241 ssh->sccipher->text_name);
7242 logeventf(ssh, "Initialised %.200s server->client MAC algorithm%s%s",
7243 ssh->scmac->text_name,
7244 ssh->scmac_etm ? " (in ETM mode)" : "",
7245 ssh->sccipher->required_mac ? " (required by cipher)" : "");
7246 if (ssh->sccomp->text_name)
7247 logeventf(ssh, "Initialised %s decompression",
7248 ssh->sccomp->text_name);
7251 * Free shared secret.
7256 * Key exchange is over. Loop straight back round if we have a
7257 * deferred rekey reason.
7259 if (ssh->deferred_rekey_reason) {
7260 logevent(ssh->deferred_rekey_reason);
7262 ssh->deferred_rekey_reason = NULL;
7263 goto begin_key_exchange;
7267 * Otherwise, schedule a timer for our next rekey.
7269 ssh->kex_in_progress = FALSE;
7270 ssh->last_rekey = GETTICKCOUNT();
7271 if (conf_get_int(ssh->conf, CONF_ssh_rekey_time) != 0)
7272 ssh->next_rekey = schedule_timer(conf_get_int(ssh->conf, CONF_ssh_rekey_time)*60*TICKSPERSEC,
7276 * Now we're encrypting. Begin returning 1 to the protocol main
7277 * function so that other things can run on top of the
7278 * transport. If we ever see a KEXINIT, we must go back to the
7281 * We _also_ go back to the start if we see pktin==NULL and
7282 * inlen negative, because this is a special signal meaning
7283 * `initiate client-driven rekey', and `in' contains a message
7284 * giving the reason for the rekey.
7286 * inlen==-1 means always initiate a rekey;
7287 * inlen==-2 means that userauth has completed successfully and
7288 * we should consider rekeying (for delayed compression).
7290 while (!((pktin && pktin->type == SSH2_MSG_KEXINIT) ||
7291 (!pktin && inlen < 0))) {
7293 if (!ssh->protocol_initial_phase_done) {
7294 ssh->protocol_initial_phase_done = TRUE;
7296 * Allow authconn to initialise itself.
7298 do_ssh2_authconn(ssh, NULL, 0, NULL);
7303 logevent("Server initiated key re-exchange");
7307 * authconn has seen a USERAUTH_SUCCEEDED. Time to enable
7308 * delayed compression, if it's available.
7310 * draft-miller-secsh-compression-delayed-00 says that you
7311 * negotiate delayed compression in the first key exchange, and
7312 * both sides start compressing when the server has sent
7313 * USERAUTH_SUCCESS. This has a race condition -- the server
7314 * can't know when the client has seen it, and thus which incoming
7315 * packets it should treat as compressed.
7317 * Instead, we do the initial key exchange without offering the
7318 * delayed methods, but note if the server offers them; when we
7319 * get here, if a delayed method was available that was higher
7320 * on our list than what we got, we initiate a rekey in which we
7321 * _do_ list the delayed methods (and hopefully get it as a
7322 * result). Subsequent rekeys will do the same.
7324 assert(!s->userauth_succeeded); /* should only happen once */
7325 s->userauth_succeeded = TRUE;
7326 if (!s->pending_compression)
7327 /* Can't see any point rekeying. */
7328 goto wait_for_rekey; /* this is utterly horrid */
7329 /* else fall through to rekey... */
7330 s->pending_compression = FALSE;
7333 * Now we've decided to rekey.
7335 * Special case: if the server bug is set that doesn't
7336 * allow rekeying, we give a different log message and
7337 * continue waiting. (If such a server _initiates_ a rekey,
7338 * we process it anyway!)
7340 if ((ssh->remote_bugs & BUG_SSH2_REKEY)) {
7341 logeventf(ssh, "Server bug prevents key re-exchange (%s)",
7343 /* Reset the counters, so that at least this message doesn't
7344 * hit the event log _too_ often. */
7345 ssh->outgoing_data_size = 0;
7346 ssh->incoming_data_size = 0;
7347 if (conf_get_int(ssh->conf, CONF_ssh_rekey_time) != 0) {
7349 schedule_timer(conf_get_int(ssh->conf, CONF_ssh_rekey_time)*60*TICKSPERSEC,
7352 goto wait_for_rekey; /* this is still utterly horrid */
7354 logeventf(ssh, "Initiating key re-exchange (%s)", (char *)in);
7357 goto begin_key_exchange;
7363 * Add data to an SSH-2 channel output buffer.
7365 static void ssh2_add_channel_data(struct ssh_channel *c, const char *buf,
7368 bufchain_add(&c->v.v2.outbuffer, buf, len);
7372 * Attempt to send data on an SSH-2 channel.
7374 static int ssh2_try_send(struct ssh_channel *c)
7377 struct Packet *pktout;
7380 while (c->v.v2.remwindow > 0 && bufchain_size(&c->v.v2.outbuffer) > 0) {
7383 bufchain_prefix(&c->v.v2.outbuffer, &data, &len);
7384 if ((unsigned)len > c->v.v2.remwindow)
7385 len = c->v.v2.remwindow;
7386 if ((unsigned)len > c->v.v2.remmaxpkt)
7387 len = c->v.v2.remmaxpkt;
7388 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_DATA);
7389 ssh2_pkt_adduint32(pktout, c->remoteid);
7390 ssh2_pkt_addstring_start(pktout);
7391 ssh2_pkt_addstring_data(pktout, data, len);
7392 ssh2_pkt_send(ssh, pktout);
7393 bufchain_consume(&c->v.v2.outbuffer, len);
7394 c->v.v2.remwindow -= len;
7398 * After having sent as much data as we can, return the amount
7401 ret = bufchain_size(&c->v.v2.outbuffer);
7404 * And if there's no data pending but we need to send an EOF, send
7407 if (!ret && c->pending_eof)
7408 ssh_channel_try_eof(c);
7413 static void ssh2_try_send_and_unthrottle(Ssh ssh, struct ssh_channel *c)
7416 if (c->closes & CLOSES_SENT_EOF)
7417 return; /* don't send on channels we've EOFed */
7418 bufsize = ssh2_try_send(c);
7421 case CHAN_MAINSESSION:
7422 /* stdin need not receive an unthrottle
7423 * notification since it will be polled */
7426 x11_unthrottle(c->u.x11.xconn);
7429 /* agent sockets are request/response and need no
7430 * buffer management */
7433 pfd_unthrottle(c->u.pfd.pf);
7439 static int ssh_is_simple(Ssh ssh)
7442 * We use the 'simple' variant of the SSH protocol if we're asked
7443 * to, except not if we're also doing connection-sharing (either
7444 * tunnelling our packets over an upstream or expecting to be
7445 * tunnelled over ourselves), since then the assumption that we
7446 * have only one channel to worry about is not true after all.
7448 return (conf_get_int(ssh->conf, CONF_ssh_simple) &&
7449 !ssh->bare_connection && !ssh->connshare);
7453 * Set up most of a new ssh_channel for SSH-2.
7455 static void ssh2_channel_init(struct ssh_channel *c)
7458 c->localid = alloc_channel_id(ssh);
7460 c->pending_eof = FALSE;
7461 c->throttling_conn = FALSE;
7462 c->v.v2.locwindow = c->v.v2.locmaxwin = c->v.v2.remlocwin =
7463 ssh_is_simple(ssh) ? OUR_V2_BIGWIN : OUR_V2_WINSIZE;
7464 c->v.v2.chanreq_head = NULL;
7465 c->v.v2.throttle_state = UNTHROTTLED;
7466 bufchain_init(&c->v.v2.outbuffer);
7470 * Construct the common parts of a CHANNEL_OPEN.
7472 static struct Packet *ssh2_chanopen_init(struct ssh_channel *c,
7475 struct Packet *pktout;
7477 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN);
7478 ssh2_pkt_addstring(pktout, type);
7479 ssh2_pkt_adduint32(pktout, c->localid);
7480 ssh2_pkt_adduint32(pktout, c->v.v2.locwindow);/* our window size */
7481 ssh2_pkt_adduint32(pktout, OUR_V2_MAXPKT); /* our max pkt size */
7486 * CHANNEL_FAILURE doesn't come with any indication of what message
7487 * caused it, so we have to keep track of the outstanding
7488 * CHANNEL_REQUESTs ourselves.
7490 static void ssh2_queue_chanreq_handler(struct ssh_channel *c,
7491 cchandler_fn_t handler, void *ctx)
7493 struct outstanding_channel_request *ocr =
7494 snew(struct outstanding_channel_request);
7496 assert(!(c->closes & (CLOSES_SENT_CLOSE | CLOSES_RCVD_CLOSE)));
7497 ocr->handler = handler;
7500 if (!c->v.v2.chanreq_head)
7501 c->v.v2.chanreq_head = ocr;
7503 c->v.v2.chanreq_tail->next = ocr;
7504 c->v.v2.chanreq_tail = ocr;
7508 * Construct the common parts of a CHANNEL_REQUEST. If handler is not
7509 * NULL then a reply will be requested and the handler will be called
7510 * when it arrives. The returned packet is ready to have any
7511 * request-specific data added and be sent. Note that if a handler is
7512 * provided, it's essential that the request actually be sent.
7514 * The handler will usually be passed the response packet in pktin. If
7515 * pktin is NULL, this means that no reply will ever be forthcoming
7516 * (e.g. because the entire connection is being destroyed, or because
7517 * the server initiated channel closure before we saw the response)
7518 * and the handler should free any storage it's holding.
7520 static struct Packet *ssh2_chanreq_init(struct ssh_channel *c,
7522 cchandler_fn_t handler, void *ctx)
7524 struct Packet *pktout;
7526 assert(!(c->closes & (CLOSES_SENT_CLOSE | CLOSES_RCVD_CLOSE)));
7527 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
7528 ssh2_pkt_adduint32(pktout, c->remoteid);
7529 ssh2_pkt_addstring(pktout, type);
7530 ssh2_pkt_addbool(pktout, handler != NULL);
7531 if (handler != NULL)
7532 ssh2_queue_chanreq_handler(c, handler, ctx);
7537 * Potentially enlarge the window on an SSH-2 channel.
7539 static void ssh2_handle_winadj_response(struct ssh_channel *, struct Packet *,
7541 static void ssh2_set_window(struct ssh_channel *c, int newwin)
7546 * Never send WINDOW_ADJUST for a channel that the remote side has
7547 * already sent EOF on; there's no point, since it won't be
7548 * sending any more data anyway. Ditto if _we've_ already sent
7551 if (c->closes & (CLOSES_RCVD_EOF | CLOSES_SENT_CLOSE))
7555 * Also, never widen the window for an X11 channel when we're
7556 * still waiting to see its initial auth and may yet hand it off
7559 if (c->type == CHAN_X11 && c->u.x11.initial)
7563 * If the remote end has a habit of ignoring maxpkt, limit the
7564 * window so that it has no choice (assuming it doesn't ignore the
7567 if ((ssh->remote_bugs & BUG_SSH2_MAXPKT) && newwin > OUR_V2_MAXPKT)
7568 newwin = OUR_V2_MAXPKT;
7571 * Only send a WINDOW_ADJUST if there's significantly more window
7572 * available than the other end thinks there is. This saves us
7573 * sending a WINDOW_ADJUST for every character in a shell session.
7575 * "Significant" is arbitrarily defined as half the window size.
7577 if (newwin / 2 >= c->v.v2.locwindow) {
7578 struct Packet *pktout;
7582 * In order to keep track of how much window the client
7583 * actually has available, we'd like it to acknowledge each
7584 * WINDOW_ADJUST. We can't do that directly, so we accompany
7585 * it with a CHANNEL_REQUEST that has to be acknowledged.
7587 * This is only necessary if we're opening the window wide.
7588 * If we're not, then throughput is being constrained by
7589 * something other than the maximum window size anyway.
7591 if (newwin == c->v.v2.locmaxwin &&
7592 !(ssh->remote_bugs & BUG_CHOKES_ON_WINADJ)) {
7593 up = snew(unsigned);
7594 *up = newwin - c->v.v2.locwindow;
7595 pktout = ssh2_chanreq_init(c, "winadj@putty.projects.tartarus.org",
7596 ssh2_handle_winadj_response, up);
7597 ssh2_pkt_send(ssh, pktout);
7599 if (c->v.v2.throttle_state != UNTHROTTLED)
7600 c->v.v2.throttle_state = UNTHROTTLING;
7602 /* Pretend the WINDOW_ADJUST was acked immediately. */
7603 c->v.v2.remlocwin = newwin;
7604 c->v.v2.throttle_state = THROTTLED;
7606 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
7607 ssh2_pkt_adduint32(pktout, c->remoteid);
7608 ssh2_pkt_adduint32(pktout, newwin - c->v.v2.locwindow);
7609 ssh2_pkt_send(ssh, pktout);
7610 c->v.v2.locwindow = newwin;
7615 * Find the channel associated with a message. If there's no channel,
7616 * or it's not properly open, make a noise about it and return NULL.
7618 static struct ssh_channel *ssh2_channel_msg(Ssh ssh, struct Packet *pktin)
7620 unsigned localid = ssh_pkt_getuint32(pktin);
7621 struct ssh_channel *c;
7623 c = find234(ssh->channels, &localid, ssh_channelfind);
7625 (c->type != CHAN_SHARING && c->halfopen &&
7626 pktin->type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION &&
7627 pktin->type != SSH2_MSG_CHANNEL_OPEN_FAILURE)) {
7628 char *buf = dupprintf("Received %s for %s channel %u",
7629 ssh2_pkt_type(ssh->pkt_kctx, ssh->pkt_actx,
7631 c ? "half-open" : "nonexistent", localid);
7632 ssh_disconnect(ssh, NULL, buf, SSH2_DISCONNECT_PROTOCOL_ERROR, FALSE);
7639 static void ssh2_handle_winadj_response(struct ssh_channel *c,
7640 struct Packet *pktin, void *ctx)
7642 unsigned *sizep = ctx;
7645 * Winadj responses should always be failures. However, at least
7646 * one server ("boks_sshd") is known to return SUCCESS for channel
7647 * requests it's never heard of, such as "winadj@putty". Raised
7648 * with foxt.com as bug 090916-090424, but for the sake of a quiet
7649 * life, we don't worry about what kind of response we got.
7652 c->v.v2.remlocwin += *sizep;
7655 * winadj messages are only sent when the window is fully open, so
7656 * if we get an ack of one, we know any pending unthrottle is
7659 if (c->v.v2.throttle_state == UNTHROTTLING)
7660 c->v.v2.throttle_state = UNTHROTTLED;
7663 static void ssh2_msg_channel_response(Ssh ssh, struct Packet *pktin)
7665 struct ssh_channel *c = ssh2_channel_msg(ssh, pktin);
7666 struct outstanding_channel_request *ocr;
7669 if (c->type == CHAN_SHARING) {
7670 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
7671 pktin->body, pktin->length);
7674 ocr = c->v.v2.chanreq_head;
7676 ssh2_msg_unexpected(ssh, pktin);
7679 ocr->handler(c, pktin, ocr->ctx);
7680 c->v.v2.chanreq_head = ocr->next;
7683 * We may now initiate channel-closing procedures, if that
7684 * CHANNEL_REQUEST was the last thing outstanding before we send
7687 ssh2_channel_check_close(c);
7690 static void ssh2_msg_channel_window_adjust(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 (!(c->closes & CLOSES_SENT_EOF)) {
7702 c->v.v2.remwindow += ssh_pkt_getuint32(pktin);
7703 ssh2_try_send_and_unthrottle(ssh, c);
7707 static void ssh2_msg_channel_data(Ssh ssh, struct Packet *pktin)
7711 struct ssh_channel *c;
7712 c = ssh2_channel_msg(ssh, pktin);
7715 if (c->type == CHAN_SHARING) {
7716 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
7717 pktin->body, pktin->length);
7720 if (pktin->type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
7721 ssh_pkt_getuint32(pktin) != SSH2_EXTENDED_DATA_STDERR)
7722 return; /* extended but not stderr */
7723 ssh_pkt_getstring(pktin, &data, &length);
7726 c->v.v2.locwindow -= length;
7727 c->v.v2.remlocwin -= length;
7729 case CHAN_MAINSESSION:
7731 from_backend(ssh->frontend, pktin->type ==
7732 SSH2_MSG_CHANNEL_EXTENDED_DATA,
7736 bufsize = x11_send(c->u.x11.xconn, data, length);
7739 bufsize = pfd_send(c->u.pfd.pf, data, length);
7742 while (length > 0) {
7743 if (c->u.a.lensofar < 4) {
7744 unsigned int l = min(4 - c->u.a.lensofar,
7746 memcpy(c->u.a.msglen + c->u.a.lensofar,
7750 c->u.a.lensofar += l;
7752 if (c->u.a.lensofar == 4) {
7754 4 + GET_32BIT(c->u.a.msglen);
7755 c->u.a.message = snewn(c->u.a.totallen,
7757 memcpy(c->u.a.message, c->u.a.msglen, 4);
7759 if (c->u.a.lensofar >= 4 && length > 0) {
7761 min(c->u.a.totallen - c->u.a.lensofar,
7763 memcpy(c->u.a.message + c->u.a.lensofar,
7767 c->u.a.lensofar += l;
7769 if (c->u.a.lensofar == c->u.a.totallen) {
7772 c->u.a.outstanding_requests++;
7773 if (agent_query(c->u.a.message,
7776 ssh_agentf_callback, c))
7777 ssh_agentf_callback(c, reply, replylen);
7778 sfree(c->u.a.message);
7779 c->u.a.message = NULL;
7780 c->u.a.lensofar = 0;
7787 * If it looks like the remote end hit the end of its window,
7788 * and we didn't want it to do that, think about using a
7791 if (c->v.v2.remlocwin <= 0 && c->v.v2.throttle_state == UNTHROTTLED &&
7792 c->v.v2.locmaxwin < 0x40000000)
7793 c->v.v2.locmaxwin += OUR_V2_WINSIZE;
7795 * If we are not buffering too much data,
7796 * enlarge the window again at the remote side.
7797 * If we are buffering too much, we may still
7798 * need to adjust the window if the server's
7801 ssh2_set_window(c, bufsize < c->v.v2.locmaxwin ?
7802 c->v.v2.locmaxwin - bufsize : 0);
7804 * If we're either buffering way too much data, or if we're
7805 * buffering anything at all and we're in "simple" mode,
7806 * throttle the whole channel.
7808 if ((bufsize > c->v.v2.locmaxwin || (ssh_is_simple(ssh) && bufsize>0))
7809 && !c->throttling_conn) {
7810 c->throttling_conn = 1;
7811 ssh_throttle_conn(ssh, +1);
7816 static void ssh_check_termination(Ssh ssh)
7818 if (ssh->version == 2 &&
7819 !conf_get_int(ssh->conf, CONF_ssh_no_shell) &&
7820 (ssh->channels && count234(ssh->channels) == 0) &&
7821 !(ssh->connshare && share_ndownstreams(ssh->connshare) > 0)) {
7823 * We used to send SSH_MSG_DISCONNECT here, because I'd
7824 * believed that _every_ conforming SSH-2 connection had to
7825 * end with a disconnect being sent by at least one side;
7826 * apparently I was wrong and it's perfectly OK to
7827 * unceremoniously slam the connection shut when you're done,
7828 * and indeed OpenSSH feels this is more polite than sending a
7829 * DISCONNECT. So now we don't.
7831 ssh_disconnect(ssh, "All channels closed", NULL, 0, TRUE);
7835 void ssh_sharing_downstream_connected(Ssh ssh, unsigned id,
7836 const char *peerinfo)
7839 logeventf(ssh, "Connection sharing downstream #%u connected from %s",
7842 logeventf(ssh, "Connection sharing downstream #%u connected", id);
7845 void ssh_sharing_downstream_disconnected(Ssh ssh, unsigned id)
7847 logeventf(ssh, "Connection sharing downstream #%u disconnected", id);
7848 ssh_check_termination(ssh);
7851 void ssh_sharing_logf(Ssh ssh, unsigned id, const char *logfmt, ...)
7856 va_start(ap, logfmt);
7857 buf = dupvprintf(logfmt, ap);
7860 logeventf(ssh, "Connection sharing downstream #%u: %s", id, buf);
7862 logeventf(ssh, "Connection sharing: %s", buf);
7866 static void ssh_channel_destroy(struct ssh_channel *c)
7871 case CHAN_MAINSESSION:
7872 ssh->mainchan = NULL;
7873 update_specials_menu(ssh->frontend);
7876 if (c->u.x11.xconn != NULL)
7877 x11_close(c->u.x11.xconn);
7878 logevent("Forwarded X11 connection terminated");
7881 sfree(c->u.a.message);
7884 if (c->u.pfd.pf != NULL)
7885 pfd_close(c->u.pfd.pf);
7886 logevent("Forwarded port closed");
7890 del234(ssh->channels, c);
7891 if (ssh->version == 2) {
7892 bufchain_clear(&c->v.v2.outbuffer);
7893 assert(c->v.v2.chanreq_head == NULL);
7898 * If that was the last channel left open, we might need to
7901 ssh_check_termination(ssh);
7904 static void ssh2_channel_check_close(struct ssh_channel *c)
7907 struct Packet *pktout;
7911 * If we've sent out our own CHANNEL_OPEN but not yet seen
7912 * either OPEN_CONFIRMATION or OPEN_FAILURE in response, then
7913 * it's too early to be sending close messages of any kind.
7918 if ((!((CLOSES_SENT_EOF | CLOSES_RCVD_EOF) & ~c->closes) ||
7919 c->type == CHAN_ZOMBIE) &&
7920 !c->v.v2.chanreq_head &&
7921 !(c->closes & CLOSES_SENT_CLOSE)) {
7923 * We have both sent and received EOF (or the channel is a
7924 * zombie), and we have no outstanding channel requests, which
7925 * means the channel is in final wind-up. But we haven't sent
7926 * CLOSE, so let's do so now.
7928 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE);
7929 ssh2_pkt_adduint32(pktout, c->remoteid);
7930 ssh2_pkt_send(ssh, pktout);
7931 c->closes |= CLOSES_SENT_EOF | CLOSES_SENT_CLOSE;
7934 if (!((CLOSES_SENT_CLOSE | CLOSES_RCVD_CLOSE) & ~c->closes)) {
7935 assert(c->v.v2.chanreq_head == NULL);
7937 * We have both sent and received CLOSE, which means we're
7938 * completely done with the channel.
7940 ssh_channel_destroy(c);
7944 static void ssh2_channel_got_eof(struct ssh_channel *c)
7946 if (c->closes & CLOSES_RCVD_EOF)
7947 return; /* already seen EOF */
7948 c->closes |= CLOSES_RCVD_EOF;
7950 if (c->type == CHAN_X11) {
7951 x11_send_eof(c->u.x11.xconn);
7952 } else if (c->type == CHAN_AGENT) {
7953 if (c->u.a.outstanding_requests == 0) {
7954 /* Manufacture an outgoing EOF in response to the incoming one. */
7955 sshfwd_write_eof(c);
7957 } else if (c->type == CHAN_SOCKDATA) {
7958 pfd_send_eof(c->u.pfd.pf);
7959 } else if (c->type == CHAN_MAINSESSION) {
7962 if (!ssh->sent_console_eof &&
7963 (from_backend_eof(ssh->frontend) || ssh->got_pty)) {
7965 * Either from_backend_eof told us that the front end
7966 * wants us to close the outgoing side of the connection
7967 * as soon as we see EOF from the far end, or else we've
7968 * unilaterally decided to do that because we've allocated
7969 * a remote pty and hence EOF isn't a particularly
7970 * meaningful concept.
7972 sshfwd_write_eof(c);
7974 ssh->sent_console_eof = TRUE;
7977 ssh2_channel_check_close(c);
7980 static void ssh2_msg_channel_eof(Ssh ssh, struct Packet *pktin)
7982 struct ssh_channel *c;
7984 c = ssh2_channel_msg(ssh, pktin);
7987 if (c->type == CHAN_SHARING) {
7988 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
7989 pktin->body, pktin->length);
7992 ssh2_channel_got_eof(c);
7995 static void ssh2_msg_channel_close(Ssh ssh, struct Packet *pktin)
7997 struct ssh_channel *c;
7999 c = ssh2_channel_msg(ssh, pktin);
8002 if (c->type == CHAN_SHARING) {
8003 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
8004 pktin->body, pktin->length);
8009 * When we receive CLOSE on a channel, we assume it comes with an
8010 * implied EOF if we haven't seen EOF yet.
8012 ssh2_channel_got_eof(c);
8014 if (!(ssh->remote_bugs & BUG_SENDS_LATE_REQUEST_REPLY)) {
8016 * It also means we stop expecting to see replies to any
8017 * outstanding channel requests, so clean those up too.
8018 * (ssh_chanreq_init will enforce by assertion that we don't
8019 * subsequently put anything back on this list.)
8021 while (c->v.v2.chanreq_head) {
8022 struct outstanding_channel_request *ocr = c->v.v2.chanreq_head;
8023 ocr->handler(c, NULL, ocr->ctx);
8024 c->v.v2.chanreq_head = ocr->next;
8030 * And we also send an outgoing EOF, if we haven't already, on the
8031 * assumption that CLOSE is a pretty forceful announcement that
8032 * the remote side is doing away with the entire channel. (If it
8033 * had wanted to send us EOF and continue receiving data from us,
8034 * it would have just sent CHANNEL_EOF.)
8036 if (!(c->closes & CLOSES_SENT_EOF)) {
8038 * Make sure we don't read any more from whatever our local
8039 * data source is for this channel.
8042 case CHAN_MAINSESSION:
8043 ssh->send_ok = 0; /* stop trying to read from stdin */
8046 x11_override_throttle(c->u.x11.xconn, 1);
8049 pfd_override_throttle(c->u.pfd.pf, 1);
8054 * Abandon any buffered data we still wanted to send to this
8055 * channel. Receiving a CHANNEL_CLOSE is an indication that
8056 * the server really wants to get on and _destroy_ this
8057 * channel, and it isn't going to send us any further
8058 * WINDOW_ADJUSTs to permit us to send pending stuff.
8060 bufchain_clear(&c->v.v2.outbuffer);
8063 * Send outgoing EOF.
8065 sshfwd_write_eof(c);
8069 * Now process the actual close.
8071 if (!(c->closes & CLOSES_RCVD_CLOSE)) {
8072 c->closes |= CLOSES_RCVD_CLOSE;
8073 ssh2_channel_check_close(c);
8077 static void ssh2_msg_channel_open_confirmation(Ssh ssh, struct Packet *pktin)
8079 struct ssh_channel *c;
8081 c = ssh2_channel_msg(ssh, pktin);
8084 if (c->type == CHAN_SHARING) {
8085 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
8086 pktin->body, pktin->length);
8089 assert(c->halfopen); /* ssh2_channel_msg will have enforced this */
8090 c->remoteid = ssh_pkt_getuint32(pktin);
8091 c->halfopen = FALSE;
8092 c->v.v2.remwindow = ssh_pkt_getuint32(pktin);
8093 c->v.v2.remmaxpkt = ssh_pkt_getuint32(pktin);
8095 if (c->type == CHAN_SOCKDATA_DORMANT) {
8096 c->type = CHAN_SOCKDATA;
8098 pfd_confirm(c->u.pfd.pf);
8099 } else if (c->type == CHAN_ZOMBIE) {
8101 * This case can occur if a local socket error occurred
8102 * between us sending out CHANNEL_OPEN and receiving
8103 * OPEN_CONFIRMATION. In this case, all we can do is
8104 * immediately initiate close proceedings now that we know the
8105 * server's id to put in the close message.
8107 ssh2_channel_check_close(c);
8110 * We never expect to receive OPEN_CONFIRMATION for any
8111 * *other* channel type (since only local-to-remote port
8112 * forwardings cause us to send CHANNEL_OPEN after the main
8113 * channel is live - all other auxiliary channel types are
8114 * initiated from the server end). It's safe to enforce this
8115 * by assertion rather than by ssh_disconnect, because the
8116 * real point is that we never constructed a half-open channel
8117 * structure in the first place with any type other than the
8120 assert(!"Funny channel type in ssh2_msg_channel_open_confirmation");
8124 ssh_channel_try_eof(c); /* in case we had a pending EOF */
8127 static void ssh2_msg_channel_open_failure(Ssh ssh, struct Packet *pktin)
8129 static const char *const reasons[] = {
8130 "<unknown reason code>",
8131 "Administratively prohibited",
8133 "Unknown channel type",
8134 "Resource shortage",
8136 unsigned reason_code;
8137 char *reason_string;
8139 struct ssh_channel *c;
8141 c = ssh2_channel_msg(ssh, pktin);
8144 if (c->type == CHAN_SHARING) {
8145 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
8146 pktin->body, pktin->length);
8149 assert(c->halfopen); /* ssh2_channel_msg will have enforced this */
8151 if (c->type == CHAN_SOCKDATA_DORMANT) {
8152 reason_code = ssh_pkt_getuint32(pktin);
8153 if (reason_code >= lenof(reasons))
8154 reason_code = 0; /* ensure reasons[reason_code] in range */
8155 ssh_pkt_getstring(pktin, &reason_string, &reason_length);
8156 logeventf(ssh, "Forwarded connection refused by server: %s [%.*s]",
8157 reasons[reason_code], reason_length, reason_string);
8159 pfd_close(c->u.pfd.pf);
8160 } else if (c->type == CHAN_ZOMBIE) {
8162 * This case can occur if a local socket error occurred
8163 * between us sending out CHANNEL_OPEN and receiving
8164 * OPEN_FAILURE. In this case, we need do nothing except allow
8165 * the code below to throw the half-open channel away.
8169 * We never expect to receive OPEN_FAILURE for any *other*
8170 * channel type (since only local-to-remote port forwardings
8171 * cause us to send CHANNEL_OPEN after the main channel is
8172 * live - all other auxiliary channel types are initiated from
8173 * the server end). It's safe to enforce this by assertion
8174 * rather than by ssh_disconnect, because the real point is
8175 * that we never constructed a half-open channel structure in
8176 * the first place with any type other than the above.
8178 assert(!"Funny channel type in ssh2_msg_channel_open_failure");
8181 del234(ssh->channels, c);
8185 static void ssh2_msg_channel_request(Ssh ssh, struct Packet *pktin)
8188 int typelen, want_reply;
8189 int reply = SSH2_MSG_CHANNEL_FAILURE; /* default */
8190 struct ssh_channel *c;
8191 struct Packet *pktout;
8193 c = ssh2_channel_msg(ssh, pktin);
8196 if (c->type == CHAN_SHARING) {
8197 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
8198 pktin->body, pktin->length);
8201 ssh_pkt_getstring(pktin, &type, &typelen);
8202 want_reply = ssh2_pkt_getbool(pktin);
8204 if (c->closes & CLOSES_SENT_CLOSE) {
8206 * We don't reply to channel requests after we've sent
8207 * CHANNEL_CLOSE for the channel, because our reply might
8208 * cross in the network with the other side's CHANNEL_CLOSE
8209 * and arrive after they have wound the channel up completely.
8215 * Having got the channel number, we now look at
8216 * the request type string to see if it's something
8219 if (c == ssh->mainchan) {
8221 * We recognise "exit-status" and "exit-signal" on
8222 * the primary channel.
8224 if (typelen == 11 &&
8225 !memcmp(type, "exit-status", 11)) {
8227 ssh->exitcode = ssh_pkt_getuint32(pktin);
8228 logeventf(ssh, "Server sent command exit status %d",
8230 reply = SSH2_MSG_CHANNEL_SUCCESS;
8232 } else if (typelen == 11 &&
8233 !memcmp(type, "exit-signal", 11)) {
8235 int is_plausible = TRUE, is_int = FALSE;
8236 char *fmt_sig = NULL, *fmt_msg = NULL;
8238 int msglen = 0, core = FALSE;
8239 /* ICK: older versions of OpenSSH (e.g. 3.4p1)
8240 * provide an `int' for the signal, despite its
8241 * having been a `string' in the drafts of RFC 4254 since at
8242 * least 2001. (Fixed in session.c 1.147.) Try to
8243 * infer which we can safely parse it as. */
8245 unsigned char *p = pktin->body +
8247 long len = pktin->length - pktin->savedpos;
8248 unsigned long num = GET_32BIT(p); /* what is it? */
8249 /* If it's 0, it hardly matters; assume string */
8253 int maybe_int = FALSE, maybe_str = FALSE;
8254 #define CHECK_HYPOTHESIS(offset, result) \
8257 int q = toint(offset); \
8258 if (q >= 0 && q+4 <= len) { \
8259 q = toint(q + 4 + GET_32BIT(p+q)); \
8260 if (q >= 0 && q+4 <= len && \
8261 ((q = toint(q + 4 + GET_32BIT(p+q))) != 0) && \
8266 CHECK_HYPOTHESIS(4+1, maybe_int);
8267 CHECK_HYPOTHESIS(4+num+1, maybe_str);
8268 #undef CHECK_HYPOTHESIS
8269 if (maybe_int && !maybe_str)
8271 else if (!maybe_int && maybe_str)
8274 /* Crikey. Either or neither. Panic. */
8275 is_plausible = FALSE;
8278 ssh->exitcode = 128; /* means `unknown signal' */
8281 /* Old non-standard OpenSSH. */
8282 int signum = ssh_pkt_getuint32(pktin);
8283 fmt_sig = dupprintf(" %d", signum);
8284 ssh->exitcode = 128 + signum;
8286 /* As per RFC 4254. */
8289 ssh_pkt_getstring(pktin, &sig, &siglen);
8290 /* Signal name isn't supposed to be blank, but
8291 * let's cope gracefully if it is. */
8293 fmt_sig = dupprintf(" \"%.*s\"",
8298 * Really hideous method of translating the
8299 * signal description back into a locally
8300 * meaningful number.
8305 #define TRANSLATE_SIGNAL(s) \
8306 else if (siglen == lenof(#s)-1 && !memcmp(sig, #s, siglen)) \
8307 ssh->exitcode = 128 + SIG ## s
8309 TRANSLATE_SIGNAL(ABRT);
8312 TRANSLATE_SIGNAL(ALRM);
8315 TRANSLATE_SIGNAL(FPE);
8318 TRANSLATE_SIGNAL(HUP);
8321 TRANSLATE_SIGNAL(ILL);
8324 TRANSLATE_SIGNAL(INT);
8327 TRANSLATE_SIGNAL(KILL);
8330 TRANSLATE_SIGNAL(PIPE);
8333 TRANSLATE_SIGNAL(QUIT);
8336 TRANSLATE_SIGNAL(SEGV);
8339 TRANSLATE_SIGNAL(TERM);
8342 TRANSLATE_SIGNAL(USR1);
8345 TRANSLATE_SIGNAL(USR2);
8347 #undef TRANSLATE_SIGNAL
8349 ssh->exitcode = 128;
8351 core = ssh2_pkt_getbool(pktin);
8352 ssh_pkt_getstring(pktin, &msg, &msglen);
8354 fmt_msg = dupprintf(" (\"%.*s\")", msglen, msg);
8356 /* ignore lang tag */
8357 } /* else don't attempt to parse */
8358 logeventf(ssh, "Server exited on signal%s%s%s",
8359 fmt_sig ? fmt_sig : "",
8360 core ? " (core dumped)" : "",
8361 fmt_msg ? fmt_msg : "");
8364 reply = SSH2_MSG_CHANNEL_SUCCESS;
8369 * This is a channel request we don't know
8370 * about, so we now either ignore the request
8371 * or respond with CHANNEL_FAILURE, depending
8374 reply = SSH2_MSG_CHANNEL_FAILURE;
8377 pktout = ssh2_pkt_init(reply);
8378 ssh2_pkt_adduint32(pktout, c->remoteid);
8379 ssh2_pkt_send(ssh, pktout);
8383 static void ssh2_msg_global_request(Ssh ssh, struct Packet *pktin)
8386 int typelen, want_reply;
8387 struct Packet *pktout;
8389 ssh_pkt_getstring(pktin, &type, &typelen);
8390 want_reply = ssh2_pkt_getbool(pktin);
8393 * We currently don't support any global requests
8394 * at all, so we either ignore the request or
8395 * respond with REQUEST_FAILURE, depending on
8399 pktout = ssh2_pkt_init(SSH2_MSG_REQUEST_FAILURE);
8400 ssh2_pkt_send(ssh, pktout);
8404 struct X11FakeAuth *ssh_sharing_add_x11_display(Ssh ssh, int authtype,
8408 struct X11FakeAuth *auth;
8411 * Make up a new set of fake X11 auth data, and add it to the tree
8412 * of currently valid ones with an indication of the sharing
8413 * context that it's relevant to.
8415 auth = x11_invent_fake_auth(ssh->x11authtree, authtype);
8416 auth->share_cs = share_cs;
8417 auth->share_chan = share_chan;
8422 void ssh_sharing_remove_x11_display(Ssh ssh, struct X11FakeAuth *auth)
8424 del234(ssh->x11authtree, auth);
8425 x11_free_fake_auth(auth);
8428 static void ssh2_msg_channel_open(Ssh ssh, struct Packet *pktin)
8435 const char *error = NULL;
8436 struct ssh_channel *c;
8437 unsigned remid, winsize, pktsize;
8438 unsigned our_winsize_override = 0;
8439 struct Packet *pktout;
8441 ssh_pkt_getstring(pktin, &type, &typelen);
8442 c = snew(struct ssh_channel);
8445 remid = ssh_pkt_getuint32(pktin);
8446 winsize = ssh_pkt_getuint32(pktin);
8447 pktsize = ssh_pkt_getuint32(pktin);
8449 if (typelen == 3 && !memcmp(type, "x11", 3)) {
8452 ssh_pkt_getstring(pktin, &peeraddr, &peeraddrlen);
8453 addrstr = snewn(peeraddrlen+1, char);
8454 memcpy(addrstr, peeraddr, peeraddrlen);
8455 addrstr[peeraddrlen] = '\0';
8456 peerport = ssh_pkt_getuint32(pktin);
8458 logeventf(ssh, "Received X11 connect request from %s:%d",
8461 if (!ssh->X11_fwd_enabled && !ssh->connshare)
8462 error = "X11 forwarding is not enabled";
8464 c->u.x11.xconn = x11_init(ssh->x11authtree, c,
8467 c->u.x11.initial = TRUE;
8470 * If we are a connection-sharing upstream, then we should
8471 * initially present a very small window, adequate to take
8472 * the X11 initial authorisation packet but not much more.
8473 * Downstream will then present us a larger window (by
8474 * fiat of the connection-sharing protocol) and we can
8475 * guarantee to send a positive-valued WINDOW_ADJUST.
8478 our_winsize_override = 128;
8480 logevent("Opened X11 forward channel");
8484 } else if (typelen == 15 &&
8485 !memcmp(type, "forwarded-tcpip", 15)) {
8486 struct ssh_rportfwd pf, *realpf;
8489 ssh_pkt_getstring(pktin, &shost, &shostlen);/* skip address */
8490 pf.shost = dupprintf("%.*s", shostlen, shost);
8491 pf.sport = ssh_pkt_getuint32(pktin);
8492 ssh_pkt_getstring(pktin, &peeraddr, &peeraddrlen);
8493 peerport = ssh_pkt_getuint32(pktin);
8494 realpf = find234(ssh->rportfwds, &pf, NULL);
8495 logeventf(ssh, "Received remote port %s:%d open request "
8496 "from %s:%d", pf.shost, pf.sport, peeraddr, peerport);
8499 if (realpf == NULL) {
8500 error = "Remote port is not recognised";
8504 if (realpf->share_ctx) {
8506 * This port forwarding is on behalf of a
8507 * connection-sharing downstream, so abandon our own
8508 * channel-open procedure and just pass the message on
8511 share_got_pkt_from_server(realpf->share_ctx, pktin->type,
8512 pktin->body, pktin->length);
8517 err = pfd_connect(&c->u.pfd.pf, realpf->dhost, realpf->dport,
8518 c, ssh->conf, realpf->pfrec->addressfamily);
8519 logeventf(ssh, "Attempting to forward remote port to "
8520 "%s:%d", realpf->dhost, realpf->dport);
8522 logeventf(ssh, "Port open failed: %s", err);
8524 error = "Port open failed";
8526 logevent("Forwarded port opened successfully");
8527 c->type = CHAN_SOCKDATA;
8530 } else if (typelen == 22 &&
8531 !memcmp(type, "auth-agent@openssh.com", 22)) {
8532 if (!ssh->agentfwd_enabled)
8533 error = "Agent forwarding is not enabled";
8535 c->type = CHAN_AGENT; /* identify channel type */
8536 c->u.a.lensofar = 0;
8537 c->u.a.message = NULL;
8538 c->u.a.outstanding_requests = 0;
8541 error = "Unsupported channel type requested";
8544 c->remoteid = remid;
8545 c->halfopen = FALSE;
8547 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_FAILURE);
8548 ssh2_pkt_adduint32(pktout, c->remoteid);
8549 ssh2_pkt_adduint32(pktout, SSH2_OPEN_CONNECT_FAILED);
8550 ssh2_pkt_addstring(pktout, error);
8551 ssh2_pkt_addstring(pktout, "en"); /* language tag */
8552 ssh2_pkt_send(ssh, pktout);
8553 logeventf(ssh, "Rejected channel open: %s", error);
8556 ssh2_channel_init(c);
8557 c->v.v2.remwindow = winsize;
8558 c->v.v2.remmaxpkt = pktsize;
8559 if (our_winsize_override) {
8560 c->v.v2.locwindow = c->v.v2.locmaxwin = c->v.v2.remlocwin =
8561 our_winsize_override;
8563 add234(ssh->channels, c);
8564 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
8565 ssh2_pkt_adduint32(pktout, c->remoteid);
8566 ssh2_pkt_adduint32(pktout, c->localid);
8567 ssh2_pkt_adduint32(pktout, c->v.v2.locwindow);
8568 ssh2_pkt_adduint32(pktout, OUR_V2_MAXPKT); /* our max pkt size */
8569 ssh2_pkt_send(ssh, pktout);
8573 void sshfwd_x11_sharing_handover(struct ssh_channel *c,
8574 void *share_cs, void *share_chan,
8575 const char *peer_addr, int peer_port,
8576 int endian, int protomajor, int protominor,
8577 const void *initial_data, int initial_len)
8580 * This function is called when we've just discovered that an X
8581 * forwarding channel on which we'd been handling the initial auth
8582 * ourselves turns out to be destined for a connection-sharing
8583 * downstream. So we turn the channel into a CHAN_SHARING, meaning
8584 * that we completely stop tracking windows and buffering data and
8585 * just pass more or less unmodified SSH messages back and forth.
8587 c->type = CHAN_SHARING;
8588 c->u.sharing.ctx = share_cs;
8589 share_setup_x11_channel(share_cs, share_chan,
8590 c->localid, c->remoteid, c->v.v2.remwindow,
8591 c->v.v2.remmaxpkt, c->v.v2.locwindow,
8592 peer_addr, peer_port, endian,
8593 protomajor, protominor,
8594 initial_data, initial_len);
8597 void sshfwd_x11_is_local(struct ssh_channel *c)
8600 * This function is called when we've just discovered that an X
8601 * forwarding channel is _not_ destined for a connection-sharing
8602 * downstream but we're going to handle it ourselves. We stop
8603 * presenting a cautiously small window and go into ordinary data
8606 c->u.x11.initial = FALSE;
8607 ssh2_set_window(c, ssh_is_simple(c->ssh) ? OUR_V2_BIGWIN : OUR_V2_WINSIZE);
8611 * Buffer banner messages for later display at some convenient point,
8612 * if we're going to display them.
8614 static void ssh2_msg_userauth_banner(Ssh ssh, struct Packet *pktin)
8616 /* Arbitrary limit to prevent unbounded inflation of buffer */
8617 if (conf_get_int(ssh->conf, CONF_ssh_show_banner) &&
8618 bufchain_size(&ssh->banner) <= 131072) {
8619 char *banner = NULL;
8621 ssh_pkt_getstring(pktin, &banner, &size);
8623 bufchain_add(&ssh->banner, banner, size);
8627 /* Helper function to deal with sending tty modes for "pty-req" */
8628 static void ssh2_send_ttymode(void *data, char *mode, char *val)
8630 struct Packet *pktout = (struct Packet *)data;
8632 unsigned int arg = 0;
8633 while (strcmp(mode, ssh_ttymodes[i].mode) != 0) i++;
8634 if (i == lenof(ssh_ttymodes)) return;
8635 switch (ssh_ttymodes[i].type) {
8637 arg = ssh_tty_parse_specchar(val);
8640 arg = ssh_tty_parse_boolean(val);
8643 ssh2_pkt_addbyte(pktout, ssh_ttymodes[i].opcode);
8644 ssh2_pkt_adduint32(pktout, arg);
8647 static void ssh2_setup_x11(struct ssh_channel *c, struct Packet *pktin,
8650 struct ssh2_setup_x11_state {
8654 struct Packet *pktout;
8655 crStateP(ssh2_setup_x11_state, ctx);
8659 logevent("Requesting X11 forwarding");
8660 pktout = ssh2_chanreq_init(ssh->mainchan, "x11-req",
8662 ssh2_pkt_addbool(pktout, 0); /* many connections */
8663 ssh2_pkt_addstring(pktout, ssh->x11auth->protoname);
8664 ssh2_pkt_addstring(pktout, ssh->x11auth->datastring);
8665 ssh2_pkt_adduint32(pktout, ssh->x11disp->screennum);
8666 ssh2_pkt_send(ssh, pktout);
8668 /* Wait to be called back with either a response packet, or NULL
8669 * meaning clean up and free our data */
8673 if (pktin->type == SSH2_MSG_CHANNEL_SUCCESS) {
8674 logevent("X11 forwarding enabled");
8675 ssh->X11_fwd_enabled = TRUE;
8677 logevent("X11 forwarding refused");
8683 static void ssh2_setup_agent(struct ssh_channel *c, struct Packet *pktin,
8686 struct ssh2_setup_agent_state {
8690 struct Packet *pktout;
8691 crStateP(ssh2_setup_agent_state, ctx);
8695 logevent("Requesting OpenSSH-style agent forwarding");
8696 pktout = ssh2_chanreq_init(ssh->mainchan, "auth-agent-req@openssh.com",
8697 ssh2_setup_agent, s);
8698 ssh2_pkt_send(ssh, pktout);
8700 /* Wait to be called back with either a response packet, or NULL
8701 * meaning clean up and free our data */
8705 if (pktin->type == SSH2_MSG_CHANNEL_SUCCESS) {
8706 logevent("Agent forwarding enabled");
8707 ssh->agentfwd_enabled = TRUE;
8709 logevent("Agent forwarding refused");
8715 static void ssh2_setup_pty(struct ssh_channel *c, struct Packet *pktin,
8718 struct ssh2_setup_pty_state {
8722 struct Packet *pktout;
8723 crStateP(ssh2_setup_pty_state, ctx);
8727 /* Unpick the terminal-speed string. */
8728 /* XXX perhaps we should allow no speeds to be sent. */
8729 ssh->ospeed = 38400; ssh->ispeed = 38400; /* last-resort defaults */
8730 sscanf(conf_get_str(ssh->conf, CONF_termspeed), "%d,%d", &ssh->ospeed, &ssh->ispeed);
8731 /* Build the pty request. */
8732 pktout = ssh2_chanreq_init(ssh->mainchan, "pty-req",
8734 ssh2_pkt_addstring(pktout, conf_get_str(ssh->conf, CONF_termtype));
8735 ssh2_pkt_adduint32(pktout, ssh->term_width);
8736 ssh2_pkt_adduint32(pktout, ssh->term_height);
8737 ssh2_pkt_adduint32(pktout, 0); /* pixel width */
8738 ssh2_pkt_adduint32(pktout, 0); /* pixel height */
8739 ssh2_pkt_addstring_start(pktout);
8740 parse_ttymodes(ssh, ssh2_send_ttymode, (void *)pktout);
8741 ssh2_pkt_addbyte(pktout, SSH2_TTY_OP_ISPEED);
8742 ssh2_pkt_adduint32(pktout, ssh->ispeed);
8743 ssh2_pkt_addbyte(pktout, SSH2_TTY_OP_OSPEED);
8744 ssh2_pkt_adduint32(pktout, ssh->ospeed);
8745 ssh2_pkt_addstring_data(pktout, "\0", 1); /* TTY_OP_END */
8746 ssh2_pkt_send(ssh, pktout);
8747 ssh->state = SSH_STATE_INTERMED;
8749 /* Wait to be called back with either a response packet, or NULL
8750 * meaning clean up and free our data */
8754 if (pktin->type == SSH2_MSG_CHANNEL_SUCCESS) {
8755 logeventf(ssh, "Allocated pty (ospeed %dbps, ispeed %dbps)",
8756 ssh->ospeed, ssh->ispeed);
8757 ssh->got_pty = TRUE;
8759 c_write_str(ssh, "Server refused to allocate pty\r\n");
8760 ssh->editing = ssh->echoing = 1;
8767 static void ssh2_setup_env(struct ssh_channel *c, struct Packet *pktin,
8770 struct ssh2_setup_env_state {
8772 int num_env, env_left, env_ok;
8775 struct Packet *pktout;
8776 crStateP(ssh2_setup_env_state, ctx);
8781 * Send environment variables.
8783 * Simplest thing here is to send all the requests at once, and
8784 * then wait for a whole bunch of successes or failures.
8790 for (val = conf_get_str_strs(ssh->conf, CONF_environmt, NULL, &key);
8792 val = conf_get_str_strs(ssh->conf, CONF_environmt, key, &key)) {
8793 pktout = ssh2_chanreq_init(ssh->mainchan, "env", ssh2_setup_env, s);
8794 ssh2_pkt_addstring(pktout, key);
8795 ssh2_pkt_addstring(pktout, val);
8796 ssh2_pkt_send(ssh, pktout);
8801 logeventf(ssh, "Sent %d environment variables", s->num_env);
8806 s->env_left = s->num_env;
8808 while (s->env_left > 0) {
8809 /* Wait to be called back with either a response packet,
8810 * or NULL meaning clean up and free our data */
8812 if (!pktin) goto out;
8813 if (pktin->type == SSH2_MSG_CHANNEL_SUCCESS)
8818 if (s->env_ok == s->num_env) {
8819 logevent("All environment variables successfully set");
8820 } else if (s->env_ok == 0) {
8821 logevent("All environment variables refused");
8822 c_write_str(ssh, "Server refused to set environment variables\r\n");
8824 logeventf(ssh, "%d environment variables refused",
8825 s->num_env - s->env_ok);
8826 c_write_str(ssh, "Server refused to set all environment variables\r\n");
8834 * Handle the SSH-2 userauth and connection layers.
8836 static void ssh2_msg_authconn(Ssh ssh, struct Packet *pktin)
8838 do_ssh2_authconn(ssh, NULL, 0, pktin);
8841 static void ssh2_response_authconn(struct ssh_channel *c, struct Packet *pktin,
8845 do_ssh2_authconn(c->ssh, NULL, 0, pktin);
8848 static void do_ssh2_authconn(Ssh ssh, const unsigned char *in, int inlen,
8849 struct Packet *pktin)
8851 struct do_ssh2_authconn_state {
8855 AUTH_TYPE_PUBLICKEY,
8856 AUTH_TYPE_PUBLICKEY_OFFER_LOUD,
8857 AUTH_TYPE_PUBLICKEY_OFFER_QUIET,
8859 AUTH_TYPE_GSSAPI, /* always QUIET */
8860 AUTH_TYPE_KEYBOARD_INTERACTIVE,
8861 AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET
8863 int done_service_req;
8864 int gotit, need_pw, can_pubkey, can_passwd, can_keyb_inter;
8865 int tried_pubkey_config, done_agent;
8870 int kbd_inter_refused;
8871 int we_are_in, userauth_success;
8872 prompts_t *cur_prompt;
8877 void *publickey_blob;
8878 int publickey_bloblen;
8879 int privatekey_available, privatekey_encrypted;
8880 char *publickey_algorithm;
8881 char *publickey_comment;
8882 unsigned char agent_request[5], *agent_response, *agentp;
8883 int agent_responselen;
8884 unsigned char *pkblob_in_agent;
8886 char *pkblob, *alg, *commentp;
8887 int pklen, alglen, commentlen;
8888 int siglen, retlen, len;
8889 char *q, *agentreq, *ret;
8891 struct Packet *pktout;
8894 struct ssh_gss_library *gsslib;
8895 Ssh_gss_ctx gss_ctx;
8896 Ssh_gss_buf gss_buf;
8897 Ssh_gss_buf gss_rcvtok, gss_sndtok;
8898 Ssh_gss_name gss_srv_name;
8899 Ssh_gss_stat gss_stat;
8902 crState(do_ssh2_authconn_state);
8906 /* Register as a handler for all the messages this coroutine handles. */
8907 ssh->packet_dispatch[SSH2_MSG_SERVICE_ACCEPT] = ssh2_msg_authconn;
8908 ssh->packet_dispatch[SSH2_MSG_USERAUTH_REQUEST] = ssh2_msg_authconn;
8909 ssh->packet_dispatch[SSH2_MSG_USERAUTH_FAILURE] = ssh2_msg_authconn;
8910 ssh->packet_dispatch[SSH2_MSG_USERAUTH_SUCCESS] = ssh2_msg_authconn;
8911 ssh->packet_dispatch[SSH2_MSG_USERAUTH_BANNER] = ssh2_msg_authconn;
8912 ssh->packet_dispatch[SSH2_MSG_USERAUTH_PK_OK] = ssh2_msg_authconn;
8913 /* ssh->packet_dispatch[SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ] = ssh2_msg_authconn; duplicate case value */
8914 /* ssh->packet_dispatch[SSH2_MSG_USERAUTH_INFO_REQUEST] = ssh2_msg_authconn; duplicate case value */
8915 ssh->packet_dispatch[SSH2_MSG_USERAUTH_INFO_RESPONSE] = ssh2_msg_authconn;
8916 ssh->packet_dispatch[SSH2_MSG_GLOBAL_REQUEST] = ssh2_msg_authconn;
8917 ssh->packet_dispatch[SSH2_MSG_REQUEST_SUCCESS] = ssh2_msg_authconn;
8918 ssh->packet_dispatch[SSH2_MSG_REQUEST_FAILURE] = ssh2_msg_authconn;
8919 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN] = ssh2_msg_authconn;
8920 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_CONFIRMATION] = ssh2_msg_authconn;
8921 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_FAILURE] = ssh2_msg_authconn;
8922 ssh->packet_dispatch[SSH2_MSG_CHANNEL_WINDOW_ADJUST] = ssh2_msg_authconn;
8923 ssh->packet_dispatch[SSH2_MSG_CHANNEL_DATA] = ssh2_msg_authconn;
8924 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EXTENDED_DATA] = ssh2_msg_authconn;
8925 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EOF] = ssh2_msg_authconn;
8926 ssh->packet_dispatch[SSH2_MSG_CHANNEL_CLOSE] = ssh2_msg_authconn;
8928 s->done_service_req = FALSE;
8929 s->we_are_in = s->userauth_success = FALSE;
8930 s->agent_response = NULL;
8932 s->tried_gssapi = FALSE;
8935 if (!ssh->bare_connection) {
8936 if (!conf_get_int(ssh->conf, CONF_ssh_no_userauth)) {
8938 * Request userauth protocol, and await a response to it.
8940 s->pktout = ssh2_pkt_init(SSH2_MSG_SERVICE_REQUEST);
8941 ssh2_pkt_addstring(s->pktout, "ssh-userauth");
8942 ssh2_pkt_send(ssh, s->pktout);
8943 crWaitUntilV(pktin);
8944 if (pktin->type == SSH2_MSG_SERVICE_ACCEPT)
8945 s->done_service_req = TRUE;
8947 if (!s->done_service_req) {
8949 * Request connection protocol directly, without authentication.
8951 s->pktout = ssh2_pkt_init(SSH2_MSG_SERVICE_REQUEST);
8952 ssh2_pkt_addstring(s->pktout, "ssh-connection");
8953 ssh2_pkt_send(ssh, s->pktout);
8954 crWaitUntilV(pktin);
8955 if (pktin->type == SSH2_MSG_SERVICE_ACCEPT) {
8956 s->we_are_in = TRUE; /* no auth required */
8958 bombout(("Server refused service request"));
8963 s->we_are_in = TRUE;
8966 /* Arrange to be able to deal with any BANNERs that come in.
8967 * (We do this now as packets may come in during the next bit.) */
8968 bufchain_init(&ssh->banner);
8969 ssh->packet_dispatch[SSH2_MSG_USERAUTH_BANNER] =
8970 ssh2_msg_userauth_banner;
8973 * Misc one-time setup for authentication.
8975 s->publickey_blob = NULL;
8976 if (!s->we_are_in) {
8979 * Load the public half of any configured public key file
8982 s->keyfile = conf_get_filename(ssh->conf, CONF_keyfile);
8983 if (!filename_is_null(s->keyfile)) {
8985 logeventf(ssh, "Reading key file \"%.150s\"",
8986 filename_to_str(s->keyfile));
8987 keytype = key_type(s->keyfile);
8988 if (keytype == SSH_KEYTYPE_SSH2 ||
8989 keytype == SSH_KEYTYPE_SSH2_PUBLIC_RFC4716 ||
8990 keytype == SSH_KEYTYPE_SSH2_PUBLIC_OPENSSH) {
8993 ssh2_userkey_loadpub(s->keyfile,
8994 &s->publickey_algorithm,
8995 &s->publickey_bloblen,
8996 &s->publickey_comment, &error);
8997 if (s->publickey_blob) {
8998 s->privatekey_available = (keytype == SSH_KEYTYPE_SSH2);
8999 if (!s->privatekey_available)
9000 logeventf(ssh, "Key file contains public key only");
9001 s->privatekey_encrypted =
9002 ssh2_userkey_encrypted(s->keyfile, NULL);
9005 logeventf(ssh, "Unable to load key (%s)",
9007 msgbuf = dupprintf("Unable to load key file "
9008 "\"%.150s\" (%s)\r\n",
9009 filename_to_str(s->keyfile),
9011 c_write_str(ssh, msgbuf);
9016 logeventf(ssh, "Unable to use this key file (%s)",
9017 key_type_to_str(keytype));
9018 msgbuf = dupprintf("Unable to use key file \"%.150s\""
9020 filename_to_str(s->keyfile),
9021 key_type_to_str(keytype));
9022 c_write_str(ssh, msgbuf);
9024 s->publickey_blob = NULL;
9029 * Find out about any keys Pageant has (but if there's a
9030 * public key configured, filter out all others).
9033 s->agent_response = NULL;
9034 s->pkblob_in_agent = NULL;
9035 if (conf_get_int(ssh->conf, CONF_tryagent) && agent_exists()) {
9039 logevent("Pageant is running. Requesting keys.");
9041 /* Request the keys held by the agent. */
9042 PUT_32BIT(s->agent_request, 1);
9043 s->agent_request[4] = SSH2_AGENTC_REQUEST_IDENTITIES;
9044 if (!agent_query(s->agent_request, 5, &r, &s->agent_responselen,
9045 ssh_agent_callback, ssh)) {
9049 bombout(("Unexpected data from server while"
9050 " waiting for agent response"));
9053 } while (pktin || inlen > 0);
9054 r = ssh->agent_response;
9055 s->agent_responselen = ssh->agent_response_len;
9057 s->agent_response = (unsigned char *) r;
9058 if (s->agent_response && s->agent_responselen >= 5 &&
9059 s->agent_response[4] == SSH2_AGENT_IDENTITIES_ANSWER) {
9062 p = s->agent_response + 5;
9063 s->nkeys = toint(GET_32BIT(p));
9066 * Vet the Pageant response to ensure that the key
9067 * count and blob lengths make sense.
9070 logeventf(ssh, "Pageant response contained a negative"
9071 " key count %d", s->nkeys);
9073 goto done_agent_query;
9075 unsigned char *q = p + 4;
9076 int lenleft = s->agent_responselen - 5 - 4;
9078 for (keyi = 0; keyi < s->nkeys; keyi++) {
9079 int bloblen, commentlen;
9081 logeventf(ssh, "Pageant response was truncated");
9083 goto done_agent_query;
9085 bloblen = toint(GET_32BIT(q));
9086 if (bloblen < 0 || bloblen > lenleft) {
9087 logeventf(ssh, "Pageant response was truncated");
9089 goto done_agent_query;
9091 lenleft -= 4 + bloblen;
9093 commentlen = toint(GET_32BIT(q));
9094 if (commentlen < 0 || commentlen > lenleft) {
9095 logeventf(ssh, "Pageant response was truncated");
9097 goto done_agent_query;
9099 lenleft -= 4 + commentlen;
9100 q += 4 + commentlen;
9105 logeventf(ssh, "Pageant has %d SSH-2 keys", s->nkeys);
9106 if (s->publickey_blob) {
9107 /* See if configured key is in agent. */
9108 for (keyi = 0; keyi < s->nkeys; keyi++) {
9109 s->pklen = toint(GET_32BIT(p));
9110 if (s->pklen == s->publickey_bloblen &&
9111 !memcmp(p+4, s->publickey_blob,
9112 s->publickey_bloblen)) {
9113 logeventf(ssh, "Pageant key #%d matches "
9114 "configured key file", keyi);
9116 s->pkblob_in_agent = p;
9120 p += toint(GET_32BIT(p)) + 4; /* comment */
9122 if (!s->pkblob_in_agent) {
9123 logevent("Configured key file not in Pageant");
9128 logevent("Failed to get reply from Pageant");
9136 * We repeat this whole loop, including the username prompt,
9137 * until we manage a successful authentication. If the user
9138 * types the wrong _password_, they can be sent back to the
9139 * beginning to try another username, if this is configured on.
9140 * (If they specify a username in the config, they are never
9141 * asked, even if they do give a wrong password.)
9143 * I think this best serves the needs of
9145 * - the people who have no configuration, no keys, and just
9146 * want to try repeated (username,password) pairs until they
9147 * type both correctly
9149 * - people who have keys and configuration but occasionally
9150 * need to fall back to passwords
9152 * - people with a key held in Pageant, who might not have
9153 * logged in to a particular machine before; so they want to
9154 * type a username, and then _either_ their key will be
9155 * accepted, _or_ they will type a password. If they mistype
9156 * the username they will want to be able to get back and
9159 s->got_username = FALSE;
9160 while (!s->we_are_in) {
9164 if (s->got_username && !conf_get_int(ssh->conf, CONF_change_username)) {
9166 * We got a username last time round this loop, and
9167 * with change_username turned off we don't try to get
9170 } else if ((ssh->username = get_remote_username(ssh->conf)) == NULL) {
9171 int ret; /* need not be kept over crReturn */
9172 s->cur_prompt = new_prompts(ssh->frontend);
9173 s->cur_prompt->to_server = TRUE;
9174 s->cur_prompt->name = dupstr("SSH login name");
9175 add_prompt(s->cur_prompt, dupstr("login as: "), TRUE);
9176 ret = get_userpass_input(s->cur_prompt, NULL, 0);
9179 crWaitUntilV(!pktin);
9180 ret = get_userpass_input(s->cur_prompt, in, inlen);
9185 * get_userpass_input() failed to get a username.
9188 free_prompts(s->cur_prompt);
9189 ssh_disconnect(ssh, "No username provided", NULL, 0, TRUE);
9192 ssh->username = dupstr(s->cur_prompt->prompts[0]->result);
9193 free_prompts(s->cur_prompt);
9196 if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
9197 stuff = dupprintf("Using username \"%s\".\r\n", ssh->username);
9198 c_write_str(ssh, stuff);
9202 s->got_username = TRUE;
9205 * Send an authentication request using method "none": (a)
9206 * just in case it succeeds, and (b) so that we know what
9207 * authentication methods we can usefully try next.
9209 ssh->pkt_actx = SSH2_PKTCTX_NOAUTH;
9211 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9212 ssh2_pkt_addstring(s->pktout, ssh->username);
9213 ssh2_pkt_addstring(s->pktout, "ssh-connection");/* service requested */
9214 ssh2_pkt_addstring(s->pktout, "none"); /* method */
9215 ssh2_pkt_send(ssh, s->pktout);
9216 s->type = AUTH_TYPE_NONE;
9218 s->we_are_in = FALSE;
9220 s->tried_pubkey_config = FALSE;
9221 s->kbd_inter_refused = FALSE;
9223 /* Reset agent request state. */
9224 s->done_agent = FALSE;
9225 if (s->agent_response) {
9226 if (s->pkblob_in_agent) {
9227 s->agentp = s->pkblob_in_agent;
9229 s->agentp = s->agent_response + 5 + 4;
9235 char *methods = NULL;
9239 * Wait for the result of the last authentication request.
9242 crWaitUntilV(pktin);
9244 * Now is a convenient point to spew any banner material
9245 * that we've accumulated. (This should ensure that when
9246 * we exit the auth loop, we haven't any left to deal
9250 int size = bufchain_size(&ssh->banner);
9252 * Don't show the banner if we're operating in
9253 * non-verbose non-interactive mode. (It's probably
9254 * a script, which means nobody will read the
9255 * banner _anyway_, and moreover the printing of
9256 * the banner will screw up processing on the
9257 * output of (say) plink.)
9259 if (size && (flags & (FLAG_VERBOSE | FLAG_INTERACTIVE))) {
9260 char *banner = snewn(size, char);
9261 bufchain_fetch(&ssh->banner, banner, size);
9262 c_write_untrusted(ssh, banner, size);
9265 bufchain_clear(&ssh->banner);
9267 if (pktin->type == SSH2_MSG_USERAUTH_SUCCESS) {
9268 logevent("Access granted");
9269 s->we_are_in = s->userauth_success = TRUE;
9273 if (pktin->type != SSH2_MSG_USERAUTH_FAILURE && s->type != AUTH_TYPE_GSSAPI) {
9274 bombout(("Strange packet received during authentication: "
9275 "type %d", pktin->type));
9282 * OK, we're now sitting on a USERAUTH_FAILURE message, so
9283 * we can look at the string in it and know what we can
9284 * helpfully try next.
9286 if (pktin->type == SSH2_MSG_USERAUTH_FAILURE) {
9287 ssh_pkt_getstring(pktin, &methods, &methlen);
9288 if (!ssh2_pkt_getbool(pktin)) {
9290 * We have received an unequivocal Access
9291 * Denied. This can translate to a variety of
9292 * messages, or no message at all.
9294 * For forms of authentication which are attempted
9295 * implicitly, by which I mean without printing
9296 * anything in the window indicating that we're
9297 * trying them, we should never print 'Access
9300 * If we do print a message saying that we're
9301 * attempting some kind of authentication, it's OK
9302 * to print a followup message saying it failed -
9303 * but the message may sometimes be more specific
9304 * than simply 'Access denied'.
9306 * Additionally, if we'd just tried password
9307 * authentication, we should break out of this
9308 * whole loop so as to go back to the username
9309 * prompt (iff we're configured to allow
9310 * username change attempts).
9312 if (s->type == AUTH_TYPE_NONE) {
9314 } else if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD ||
9315 s->type == AUTH_TYPE_PUBLICKEY_OFFER_QUIET) {
9316 if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD)
9317 c_write_str(ssh, "Server refused our key\r\n");
9318 logevent("Server refused our key");
9319 } else if (s->type == AUTH_TYPE_PUBLICKEY) {
9320 /* This _shouldn't_ happen except by a
9321 * protocol bug causing client and server to
9322 * disagree on what is a correct signature. */
9323 c_write_str(ssh, "Server refused public-key signature"
9324 " despite accepting key!\r\n");
9325 logevent("Server refused public-key signature"
9326 " despite accepting key!");
9327 } else if (s->type==AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET) {
9328 /* quiet, so no c_write */
9329 logevent("Server refused keyboard-interactive authentication");
9330 } else if (s->type==AUTH_TYPE_GSSAPI) {
9331 /* always quiet, so no c_write */
9332 /* also, the code down in the GSSAPI block has
9333 * already logged this in the Event Log */
9334 } else if (s->type == AUTH_TYPE_KEYBOARD_INTERACTIVE) {
9335 logevent("Keyboard-interactive authentication failed");
9336 c_write_str(ssh, "Access denied\r\n");
9338 assert(s->type == AUTH_TYPE_PASSWORD);
9339 logevent("Password authentication failed");
9340 c_write_str(ssh, "Access denied\r\n");
9342 if (conf_get_int(ssh->conf, CONF_change_username)) {
9343 /* XXX perhaps we should allow
9344 * keyboard-interactive to do this too? */
9345 s->we_are_in = FALSE;
9350 c_write_str(ssh, "Further authentication required\r\n");
9351 logevent("Further authentication required");
9355 in_commasep_string("publickey", methods, methlen);
9357 in_commasep_string("password", methods, methlen);
9358 s->can_keyb_inter = conf_get_int(ssh->conf, CONF_try_ki_auth) &&
9359 in_commasep_string("keyboard-interactive", methods, methlen);
9361 if (conf_get_int(ssh->conf, CONF_try_gssapi_auth) &&
9362 in_commasep_string("gssapi-with-mic", methods, methlen)) {
9363 /* Try loading the GSS libraries and see if we
9366 ssh->gsslibs = ssh_gss_setup(ssh->conf);
9367 s->can_gssapi = (ssh->gsslibs->nlibraries > 0);
9369 /* No point in even bothering to try to load the
9370 * GSS libraries, if the user configuration and
9371 * server aren't both prepared to attempt GSSAPI
9372 * auth in the first place. */
9373 s->can_gssapi = FALSE;
9378 ssh->pkt_actx = SSH2_PKTCTX_NOAUTH;
9380 if (s->can_pubkey && !s->done_agent && s->nkeys) {
9383 * Attempt public-key authentication using a key from Pageant.
9386 ssh->pkt_actx = SSH2_PKTCTX_PUBLICKEY;
9388 logeventf(ssh, "Trying Pageant key #%d", s->keyi);
9390 /* Unpack key from agent response */
9391 s->pklen = toint(GET_32BIT(s->agentp));
9393 s->pkblob = (char *)s->agentp;
9394 s->agentp += s->pklen;
9395 s->alglen = toint(GET_32BIT(s->pkblob));
9396 s->alg = s->pkblob + 4;
9397 s->commentlen = toint(GET_32BIT(s->agentp));
9399 s->commentp = (char *)s->agentp;
9400 s->agentp += s->commentlen;
9401 /* s->agentp now points at next key, if any */
9403 /* See if server will accept it */
9404 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9405 ssh2_pkt_addstring(s->pktout, ssh->username);
9406 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9407 /* service requested */
9408 ssh2_pkt_addstring(s->pktout, "publickey");
9410 ssh2_pkt_addbool(s->pktout, FALSE); /* no signature included */
9411 ssh2_pkt_addstring_start(s->pktout);
9412 ssh2_pkt_addstring_data(s->pktout, s->alg, s->alglen);
9413 ssh2_pkt_addstring_start(s->pktout);
9414 ssh2_pkt_addstring_data(s->pktout, s->pkblob, s->pklen);
9415 ssh2_pkt_send(ssh, s->pktout);
9416 s->type = AUTH_TYPE_PUBLICKEY_OFFER_QUIET;
9418 crWaitUntilV(pktin);
9419 if (pktin->type != SSH2_MSG_USERAUTH_PK_OK) {
9421 /* Offer of key refused. */
9428 if (flags & FLAG_VERBOSE) {
9429 c_write_str(ssh, "Authenticating with "
9431 c_write(ssh, s->commentp, s->commentlen);
9432 c_write_str(ssh, "\" from agent\r\n");
9436 * Server is willing to accept the key.
9437 * Construct a SIGN_REQUEST.
9439 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9440 ssh2_pkt_addstring(s->pktout, ssh->username);
9441 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9442 /* service requested */
9443 ssh2_pkt_addstring(s->pktout, "publickey");
9445 ssh2_pkt_addbool(s->pktout, TRUE); /* signature included */
9446 ssh2_pkt_addstring_start(s->pktout);
9447 ssh2_pkt_addstring_data(s->pktout, s->alg, s->alglen);
9448 ssh2_pkt_addstring_start(s->pktout);
9449 ssh2_pkt_addstring_data(s->pktout, s->pkblob, s->pklen);
9451 /* Ask agent for signature. */
9452 s->siglen = s->pktout->length - 5 + 4 +
9453 ssh->v2_session_id_len;
9454 if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
9456 s->len = 1; /* message type */
9457 s->len += 4 + s->pklen; /* key blob */
9458 s->len += 4 + s->siglen; /* data to sign */
9459 s->len += 4; /* flags */
9460 s->agentreq = snewn(4 + s->len, char);
9461 PUT_32BIT(s->agentreq, s->len);
9462 s->q = s->agentreq + 4;
9463 *s->q++ = SSH2_AGENTC_SIGN_REQUEST;
9464 PUT_32BIT(s->q, s->pklen);
9466 memcpy(s->q, s->pkblob, s->pklen);
9468 PUT_32BIT(s->q, s->siglen);
9470 /* Now the data to be signed... */
9471 if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
9472 PUT_32BIT(s->q, ssh->v2_session_id_len);
9475 memcpy(s->q, ssh->v2_session_id,
9476 ssh->v2_session_id_len);
9477 s->q += ssh->v2_session_id_len;
9478 memcpy(s->q, s->pktout->data + 5,
9479 s->pktout->length - 5);
9480 s->q += s->pktout->length - 5;
9481 /* And finally the (zero) flags word. */
9483 if (!agent_query(s->agentreq, s->len + 4,
9485 ssh_agent_callback, ssh)) {
9489 bombout(("Unexpected data from server"
9490 " while waiting for agent"
9494 } while (pktin || inlen > 0);
9495 vret = ssh->agent_response;
9496 s->retlen = ssh->agent_response_len;
9501 if (s->retlen >= 9 &&
9502 s->ret[4] == SSH2_AGENT_SIGN_RESPONSE &&
9503 GET_32BIT(s->ret + 5) <= (unsigned)(s->retlen-9)) {
9504 logevent("Sending Pageant's response");
9505 ssh2_add_sigblob(ssh, s->pktout,
9506 s->pkblob, s->pklen,
9508 GET_32BIT(s->ret + 5));
9509 ssh2_pkt_send(ssh, s->pktout);
9510 s->type = AUTH_TYPE_PUBLICKEY;
9512 /* FIXME: less drastic response */
9513 bombout(("Pageant failed to answer challenge"));
9519 /* Do we have any keys left to try? */
9520 if (s->pkblob_in_agent) {
9521 s->done_agent = TRUE;
9522 s->tried_pubkey_config = TRUE;
9525 if (s->keyi >= s->nkeys)
9526 s->done_agent = TRUE;
9529 } else if (s->can_pubkey && s->publickey_blob &&
9530 s->privatekey_available && !s->tried_pubkey_config) {
9532 struct ssh2_userkey *key; /* not live over crReturn */
9533 char *passphrase; /* not live over crReturn */
9535 ssh->pkt_actx = SSH2_PKTCTX_PUBLICKEY;
9537 s->tried_pubkey_config = TRUE;
9540 * Try the public key supplied in the configuration.
9542 * First, offer the public blob to see if the server is
9543 * willing to accept it.
9545 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9546 ssh2_pkt_addstring(s->pktout, ssh->username);
9547 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9548 /* service requested */
9549 ssh2_pkt_addstring(s->pktout, "publickey"); /* method */
9550 ssh2_pkt_addbool(s->pktout, FALSE);
9551 /* no signature included */
9552 ssh2_pkt_addstring(s->pktout, s->publickey_algorithm);
9553 ssh2_pkt_addstring_start(s->pktout);
9554 ssh2_pkt_addstring_data(s->pktout,
9555 (char *)s->publickey_blob,
9556 s->publickey_bloblen);
9557 ssh2_pkt_send(ssh, s->pktout);
9558 logevent("Offered public key");
9560 crWaitUntilV(pktin);
9561 if (pktin->type != SSH2_MSG_USERAUTH_PK_OK) {
9562 /* Key refused. Give up. */
9563 s->gotit = TRUE; /* reconsider message next loop */
9564 s->type = AUTH_TYPE_PUBLICKEY_OFFER_LOUD;
9565 continue; /* process this new message */
9567 logevent("Offer of public key accepted");
9570 * Actually attempt a serious authentication using
9573 if (flags & FLAG_VERBOSE) {
9574 c_write_str(ssh, "Authenticating with public key \"");
9575 c_write_str(ssh, s->publickey_comment);
9576 c_write_str(ssh, "\"\r\n");
9580 const char *error; /* not live over crReturn */
9581 if (s->privatekey_encrypted) {
9583 * Get a passphrase from the user.
9585 int ret; /* need not be kept over crReturn */
9586 s->cur_prompt = new_prompts(ssh->frontend);
9587 s->cur_prompt->to_server = FALSE;
9588 s->cur_prompt->name = dupstr("SSH key passphrase");
9589 add_prompt(s->cur_prompt,
9590 dupprintf("Passphrase for key \"%.100s\": ",
9591 s->publickey_comment),
9593 ret = get_userpass_input(s->cur_prompt, NULL, 0);
9596 crWaitUntilV(!pktin);
9597 ret = get_userpass_input(s->cur_prompt,
9602 /* Failed to get a passphrase. Terminate. */
9603 free_prompts(s->cur_prompt);
9604 ssh_disconnect(ssh, NULL,
9605 "Unable to authenticate",
9606 SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER,
9611 dupstr(s->cur_prompt->prompts[0]->result);
9612 free_prompts(s->cur_prompt);
9614 passphrase = NULL; /* no passphrase needed */
9618 * Try decrypting the key.
9620 s->keyfile = conf_get_filename(ssh->conf, CONF_keyfile);
9621 key = ssh2_load_userkey(s->keyfile, passphrase, &error);
9623 /* burn the evidence */
9624 smemclr(passphrase, strlen(passphrase));
9627 if (key == SSH2_WRONG_PASSPHRASE || key == NULL) {
9629 (key == SSH2_WRONG_PASSPHRASE)) {
9630 c_write_str(ssh, "Wrong passphrase\r\n");
9632 /* and loop again */
9634 c_write_str(ssh, "Unable to load private key (");
9635 c_write_str(ssh, error);
9636 c_write_str(ssh, ")\r\n");
9638 break; /* try something else */
9644 unsigned char *pkblob, *sigblob, *sigdata;
9645 int pkblob_len, sigblob_len, sigdata_len;
9649 * We have loaded the private key and the server
9650 * has announced that it's willing to accept it.
9651 * Hallelujah. Generate a signature and send it.
9653 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9654 ssh2_pkt_addstring(s->pktout, ssh->username);
9655 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9656 /* service requested */
9657 ssh2_pkt_addstring(s->pktout, "publickey");
9659 ssh2_pkt_addbool(s->pktout, TRUE);
9660 /* signature follows */
9661 ssh2_pkt_addstring(s->pktout, key->alg->name);
9662 pkblob = key->alg->public_blob(key->data,
9664 ssh2_pkt_addstring_start(s->pktout);
9665 ssh2_pkt_addstring_data(s->pktout, (char *)pkblob,
9669 * The data to be signed is:
9673 * followed by everything so far placed in the
9676 sigdata_len = s->pktout->length - 5 + 4 +
9677 ssh->v2_session_id_len;
9678 if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
9680 sigdata = snewn(sigdata_len, unsigned char);
9682 if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
9683 PUT_32BIT(sigdata+p, ssh->v2_session_id_len);
9686 memcpy(sigdata+p, ssh->v2_session_id,
9687 ssh->v2_session_id_len);
9688 p += ssh->v2_session_id_len;
9689 memcpy(sigdata+p, s->pktout->data + 5,
9690 s->pktout->length - 5);
9691 p += s->pktout->length - 5;
9692 assert(p == sigdata_len);
9693 sigblob = key->alg->sign(key->data, (char *)sigdata,
9694 sigdata_len, &sigblob_len);
9695 ssh2_add_sigblob(ssh, s->pktout, pkblob, pkblob_len,
9696 sigblob, sigblob_len);
9701 ssh2_pkt_send(ssh, s->pktout);
9702 logevent("Sent public key signature");
9703 s->type = AUTH_TYPE_PUBLICKEY;
9704 key->alg->freekey(key->data);
9705 sfree(key->comment);
9710 } else if (s->can_gssapi && !s->tried_gssapi) {
9712 /* GSSAPI Authentication */
9717 s->type = AUTH_TYPE_GSSAPI;
9718 s->tried_gssapi = TRUE;
9720 ssh->pkt_actx = SSH2_PKTCTX_GSSAPI;
9723 * Pick the highest GSS library on the preference
9729 for (i = 0; i < ngsslibs; i++) {
9730 int want_id = conf_get_int_int(ssh->conf,
9731 CONF_ssh_gsslist, i);
9732 for (j = 0; j < ssh->gsslibs->nlibraries; j++)
9733 if (ssh->gsslibs->libraries[j].id == want_id) {
9734 s->gsslib = &ssh->gsslibs->libraries[j];
9735 goto got_gsslib; /* double break */
9740 * We always expect to have found something in
9741 * the above loop: we only came here if there
9742 * was at least one viable GSS library, and the
9743 * preference list should always mention
9744 * everything and only change the order.
9749 if (s->gsslib->gsslogmsg)
9750 logevent(s->gsslib->gsslogmsg);
9752 /* Sending USERAUTH_REQUEST with "gssapi-with-mic" method */
9753 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9754 ssh2_pkt_addstring(s->pktout, ssh->username);
9755 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9756 ssh2_pkt_addstring(s->pktout, "gssapi-with-mic");
9757 logevent("Attempting GSSAPI authentication");
9759 /* add mechanism info */
9760 s->gsslib->indicate_mech(s->gsslib, &s->gss_buf);
9762 /* number of GSSAPI mechanisms */
9763 ssh2_pkt_adduint32(s->pktout,1);
9765 /* length of OID + 2 */
9766 ssh2_pkt_adduint32(s->pktout, s->gss_buf.length + 2);
9767 ssh2_pkt_addbyte(s->pktout, SSH2_GSS_OIDTYPE);
9770 ssh2_pkt_addbyte(s->pktout, (unsigned char) s->gss_buf.length);
9772 ssh_pkt_adddata(s->pktout, s->gss_buf.value,
9774 ssh2_pkt_send(ssh, s->pktout);
9775 crWaitUntilV(pktin);
9776 if (pktin->type != SSH2_MSG_USERAUTH_GSSAPI_RESPONSE) {
9777 logevent("GSSAPI authentication request refused");
9781 /* check returned packet ... */
9783 ssh_pkt_getstring(pktin, &data, &len);
9784 s->gss_rcvtok.value = data;
9785 s->gss_rcvtok.length = len;
9786 if (s->gss_rcvtok.length != s->gss_buf.length + 2 ||
9787 ((char *)s->gss_rcvtok.value)[0] != SSH2_GSS_OIDTYPE ||
9788 ((char *)s->gss_rcvtok.value)[1] != s->gss_buf.length ||
9789 memcmp((char *)s->gss_rcvtok.value + 2,
9790 s->gss_buf.value,s->gss_buf.length) ) {
9791 logevent("GSSAPI authentication - wrong response from server");
9795 /* now start running */
9796 s->gss_stat = s->gsslib->import_name(s->gsslib,
9799 if (s->gss_stat != SSH_GSS_OK) {
9800 if (s->gss_stat == SSH_GSS_BAD_HOST_NAME)
9801 logevent("GSSAPI import name failed - Bad service name");
9803 logevent("GSSAPI import name failed");
9807 /* fetch TGT into GSS engine */
9808 s->gss_stat = s->gsslib->acquire_cred(s->gsslib, &s->gss_ctx);
9810 if (s->gss_stat != SSH_GSS_OK) {
9811 logevent("GSSAPI authentication failed to get credentials");
9812 s->gsslib->release_name(s->gsslib, &s->gss_srv_name);
9816 /* initial tokens are empty */
9817 SSH_GSS_CLEAR_BUF(&s->gss_rcvtok);
9818 SSH_GSS_CLEAR_BUF(&s->gss_sndtok);
9820 /* now enter the loop */
9822 s->gss_stat = s->gsslib->init_sec_context
9826 conf_get_int(ssh->conf, CONF_gssapifwd),
9830 if (s->gss_stat!=SSH_GSS_S_COMPLETE &&
9831 s->gss_stat!=SSH_GSS_S_CONTINUE_NEEDED) {
9832 logevent("GSSAPI authentication initialisation failed");
9834 if (s->gsslib->display_status(s->gsslib, s->gss_ctx,
9835 &s->gss_buf) == SSH_GSS_OK) {
9836 logevent(s->gss_buf.value);
9837 sfree(s->gss_buf.value);
9842 logevent("GSSAPI authentication initialised");
9844 /* Client and server now exchange tokens until GSSAPI
9845 * no longer says CONTINUE_NEEDED */
9847 if (s->gss_sndtok.length != 0) {
9848 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
9849 ssh_pkt_addstring_start(s->pktout);
9850 ssh_pkt_addstring_data(s->pktout,s->gss_sndtok.value,s->gss_sndtok.length);
9851 ssh2_pkt_send(ssh, s->pktout);
9852 s->gsslib->free_tok(s->gsslib, &s->gss_sndtok);
9855 if (s->gss_stat == SSH_GSS_S_CONTINUE_NEEDED) {
9856 crWaitUntilV(pktin);
9857 if (pktin->type != SSH2_MSG_USERAUTH_GSSAPI_TOKEN) {
9858 logevent("GSSAPI authentication - bad server response");
9859 s->gss_stat = SSH_GSS_FAILURE;
9862 ssh_pkt_getstring(pktin, &data, &len);
9863 s->gss_rcvtok.value = data;
9864 s->gss_rcvtok.length = len;
9866 } while (s-> gss_stat == SSH_GSS_S_CONTINUE_NEEDED);
9868 if (s->gss_stat != SSH_GSS_OK) {
9869 s->gsslib->release_name(s->gsslib, &s->gss_srv_name);
9870 s->gsslib->release_cred(s->gsslib, &s->gss_ctx);
9873 logevent("GSSAPI authentication loop finished OK");
9875 /* Now send the MIC */
9877 s->pktout = ssh2_pkt_init(0);
9878 micoffset = s->pktout->length;
9879 ssh_pkt_addstring_start(s->pktout);
9880 ssh_pkt_addstring_data(s->pktout, (char *)ssh->v2_session_id, ssh->v2_session_id_len);
9881 ssh_pkt_addbyte(s->pktout, SSH2_MSG_USERAUTH_REQUEST);
9882 ssh_pkt_addstring(s->pktout, ssh->username);
9883 ssh_pkt_addstring(s->pktout, "ssh-connection");
9884 ssh_pkt_addstring(s->pktout, "gssapi-with-mic");
9886 s->gss_buf.value = (char *)s->pktout->data + micoffset;
9887 s->gss_buf.length = s->pktout->length - micoffset;
9889 s->gsslib->get_mic(s->gsslib, s->gss_ctx, &s->gss_buf, &mic);
9890 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_GSSAPI_MIC);
9891 ssh_pkt_addstring_start(s->pktout);
9892 ssh_pkt_addstring_data(s->pktout, mic.value, mic.length);
9893 ssh2_pkt_send(ssh, s->pktout);
9894 s->gsslib->free_mic(s->gsslib, &mic);
9898 s->gsslib->release_name(s->gsslib, &s->gss_srv_name);
9899 s->gsslib->release_cred(s->gsslib, &s->gss_ctx);
9902 } else if (s->can_keyb_inter && !s->kbd_inter_refused) {
9905 * Keyboard-interactive authentication.
9908 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
9910 ssh->pkt_actx = SSH2_PKTCTX_KBDINTER;
9912 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9913 ssh2_pkt_addstring(s->pktout, ssh->username);
9914 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9915 /* service requested */
9916 ssh2_pkt_addstring(s->pktout, "keyboard-interactive");
9918 ssh2_pkt_addstring(s->pktout, ""); /* lang */
9919 ssh2_pkt_addstring(s->pktout, ""); /* submethods */
9920 ssh2_pkt_send(ssh, s->pktout);
9922 logevent("Attempting keyboard-interactive authentication");
9924 crWaitUntilV(pktin);
9925 if (pktin->type != SSH2_MSG_USERAUTH_INFO_REQUEST) {
9926 /* Server is not willing to do keyboard-interactive
9927 * at all (or, bizarrely but legally, accepts the
9928 * user without actually issuing any prompts).
9929 * Give up on it entirely. */
9931 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET;
9932 s->kbd_inter_refused = TRUE; /* don't try it again */
9937 * Loop while the server continues to send INFO_REQUESTs.
9939 while (pktin->type == SSH2_MSG_USERAUTH_INFO_REQUEST) {
9941 char *name, *inst, *lang;
9942 int name_len, inst_len, lang_len;
9946 * We've got a fresh USERAUTH_INFO_REQUEST.
9947 * Get the preamble and start building a prompt.
9949 ssh_pkt_getstring(pktin, &name, &name_len);
9950 ssh_pkt_getstring(pktin, &inst, &inst_len);
9951 ssh_pkt_getstring(pktin, &lang, &lang_len);
9952 s->cur_prompt = new_prompts(ssh->frontend);
9953 s->cur_prompt->to_server = TRUE;
9956 * Get any prompt(s) from the packet.
9958 s->num_prompts = ssh_pkt_getuint32(pktin);
9959 for (i = 0; i < s->num_prompts; i++) {
9963 static char noprompt[] =
9964 "<server failed to send prompt>: ";
9966 ssh_pkt_getstring(pktin, &prompt, &prompt_len);
9967 echo = ssh2_pkt_getbool(pktin);
9970 prompt_len = lenof(noprompt)-1;
9972 add_prompt(s->cur_prompt,
9973 dupprintf("%.*s", prompt_len, prompt),
9978 /* FIXME: better prefix to distinguish from
9980 s->cur_prompt->name =
9981 dupprintf("SSH server: %.*s", name_len, name);
9982 s->cur_prompt->name_reqd = TRUE;
9984 s->cur_prompt->name =
9985 dupstr("SSH server authentication");
9986 s->cur_prompt->name_reqd = FALSE;
9988 /* We add a prefix to try to make it clear that a prompt
9989 * has come from the server.
9990 * FIXME: ugly to print "Using..." in prompt _every_
9991 * time round. Can this be done more subtly? */
9992 /* Special case: for reasons best known to themselves,
9993 * some servers send k-i requests with no prompts and
9994 * nothing to display. Keep quiet in this case. */
9995 if (s->num_prompts || name_len || inst_len) {
9996 s->cur_prompt->instruction =
9997 dupprintf("Using keyboard-interactive authentication.%s%.*s",
9998 inst_len ? "\n" : "", inst_len, inst);
9999 s->cur_prompt->instr_reqd = TRUE;
10001 s->cur_prompt->instr_reqd = FALSE;
10005 * Display any instructions, and get the user's
10009 int ret; /* not live over crReturn */
10010 ret = get_userpass_input(s->cur_prompt, NULL, 0);
10013 crWaitUntilV(!pktin);
10014 ret = get_userpass_input(s->cur_prompt, in, inlen);
10019 * Failed to get responses. Terminate.
10021 free_prompts(s->cur_prompt);
10022 ssh_disconnect(ssh, NULL, "Unable to authenticate",
10023 SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER,
10030 * Send the response(s) to the server.
10032 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_INFO_RESPONSE);
10033 ssh2_pkt_adduint32(s->pktout, s->num_prompts);
10034 for (i=0; i < s->num_prompts; i++) {
10035 ssh2_pkt_addstring(s->pktout,
10036 s->cur_prompt->prompts[i]->result);
10038 ssh2_pkt_send_with_padding(ssh, s->pktout, 256);
10041 * Free the prompts structure from this iteration.
10042 * If there's another, a new one will be allocated
10043 * when we return to the top of this while loop.
10045 free_prompts(s->cur_prompt);
10048 * Get the next packet in case it's another
10051 crWaitUntilV(pktin);
10056 * We should have SUCCESS or FAILURE now.
10060 } else if (s->can_passwd) {
10063 * Plain old password authentication.
10065 int ret; /* not live over crReturn */
10066 int changereq_first_time; /* not live over crReturn */
10068 ssh->pkt_actx = SSH2_PKTCTX_PASSWORD;
10070 s->cur_prompt = new_prompts(ssh->frontend);
10071 s->cur_prompt->to_server = TRUE;
10072 s->cur_prompt->name = dupstr("SSH password");
10073 add_prompt(s->cur_prompt, dupprintf("%s@%s's password: ",
10078 ret = get_userpass_input(s->cur_prompt, NULL, 0);
10081 crWaitUntilV(!pktin);
10082 ret = get_userpass_input(s->cur_prompt, in, inlen);
10087 * Failed to get responses. Terminate.
10089 free_prompts(s->cur_prompt);
10090 ssh_disconnect(ssh, NULL, "Unable to authenticate",
10091 SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER,
10096 * Squirrel away the password. (We may need it later if
10097 * asked to change it.)
10099 s->password = dupstr(s->cur_prompt->prompts[0]->result);
10100 free_prompts(s->cur_prompt);
10103 * Send the password packet.
10105 * We pad out the password packet to 256 bytes to make
10106 * it harder for an attacker to find the length of the
10109 * Anyone using a password longer than 256 bytes
10110 * probably doesn't have much to worry about from
10111 * people who find out how long their password is!
10113 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
10114 ssh2_pkt_addstring(s->pktout, ssh->username);
10115 ssh2_pkt_addstring(s->pktout, "ssh-connection");
10116 /* service requested */
10117 ssh2_pkt_addstring(s->pktout, "password");
10118 ssh2_pkt_addbool(s->pktout, FALSE);
10119 ssh2_pkt_addstring(s->pktout, s->password);
10120 ssh2_pkt_send_with_padding(ssh, s->pktout, 256);
10121 logevent("Sent password");
10122 s->type = AUTH_TYPE_PASSWORD;
10125 * Wait for next packet, in case it's a password change
10128 crWaitUntilV(pktin);
10129 changereq_first_time = TRUE;
10131 while (pktin->type == SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ) {
10134 * We're being asked for a new password
10135 * (perhaps not for the first time).
10136 * Loop until the server accepts it.
10139 int got_new = FALSE; /* not live over crReturn */
10140 char *prompt; /* not live over crReturn */
10141 int prompt_len; /* not live over crReturn */
10145 if (changereq_first_time)
10146 msg = "Server requested password change";
10148 msg = "Server rejected new password";
10150 c_write_str(ssh, msg);
10151 c_write_str(ssh, "\r\n");
10154 ssh_pkt_getstring(pktin, &prompt, &prompt_len);
10156 s->cur_prompt = new_prompts(ssh->frontend);
10157 s->cur_prompt->to_server = TRUE;
10158 s->cur_prompt->name = dupstr("New SSH password");
10159 s->cur_prompt->instruction =
10160 dupprintf("%.*s", prompt_len, prompt);
10161 s->cur_prompt->instr_reqd = TRUE;
10163 * There's no explicit requirement in the protocol
10164 * for the "old" passwords in the original and
10165 * password-change messages to be the same, and
10166 * apparently some Cisco kit supports password change
10167 * by the user entering a blank password originally
10168 * and the real password subsequently, so,
10169 * reluctantly, we prompt for the old password again.
10171 * (On the other hand, some servers don't even bother
10172 * to check this field.)
10174 add_prompt(s->cur_prompt,
10175 dupstr("Current password (blank for previously entered password): "),
10177 add_prompt(s->cur_prompt, dupstr("Enter new password: "),
10179 add_prompt(s->cur_prompt, dupstr("Confirm new password: "),
10183 * Loop until the user manages to enter the same
10188 ret = get_userpass_input(s->cur_prompt, NULL, 0);
10191 crWaitUntilV(!pktin);
10192 ret = get_userpass_input(s->cur_prompt, in, inlen);
10197 * Failed to get responses. Terminate.
10199 /* burn the evidence */
10200 free_prompts(s->cur_prompt);
10201 smemclr(s->password, strlen(s->password));
10202 sfree(s->password);
10203 ssh_disconnect(ssh, NULL, "Unable to authenticate",
10204 SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER,
10210 * If the user specified a new original password
10211 * (IYSWIM), overwrite any previously specified
10213 * (A side effect is that the user doesn't have to
10214 * re-enter it if they louse up the new password.)
10216 if (s->cur_prompt->prompts[0]->result[0]) {
10217 smemclr(s->password, strlen(s->password));
10218 /* burn the evidence */
10219 sfree(s->password);
10221 dupstr(s->cur_prompt->prompts[0]->result);
10225 * Check the two new passwords match.
10227 got_new = (strcmp(s->cur_prompt->prompts[1]->result,
10228 s->cur_prompt->prompts[2]->result)
10231 /* They don't. Silly user. */
10232 c_write_str(ssh, "Passwords do not match\r\n");
10237 * Send the new password (along with the old one).
10238 * (see above for padding rationale)
10240 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
10241 ssh2_pkt_addstring(s->pktout, ssh->username);
10242 ssh2_pkt_addstring(s->pktout, "ssh-connection");
10243 /* service requested */
10244 ssh2_pkt_addstring(s->pktout, "password");
10245 ssh2_pkt_addbool(s->pktout, TRUE);
10246 ssh2_pkt_addstring(s->pktout, s->password);
10247 ssh2_pkt_addstring(s->pktout,
10248 s->cur_prompt->prompts[1]->result);
10249 free_prompts(s->cur_prompt);
10250 ssh2_pkt_send_with_padding(ssh, s->pktout, 256);
10251 logevent("Sent new password");
10254 * Now see what the server has to say about it.
10255 * (If it's CHANGEREQ again, it's not happy with the
10258 crWaitUntilV(pktin);
10259 changereq_first_time = FALSE;
10264 * We need to reexamine the current pktin at the top
10265 * of the loop. Either:
10266 * - we weren't asked to change password at all, in
10267 * which case it's a SUCCESS or FAILURE with the
10269 * - we sent a new password, and the server was
10270 * either OK with it (SUCCESS or FAILURE w/partial
10271 * success) or unhappy with the _old_ password
10272 * (FAILURE w/o partial success)
10273 * In any of these cases, we go back to the top of
10274 * the loop and start again.
10279 * We don't need the old password any more, in any
10280 * case. Burn the evidence.
10282 smemclr(s->password, strlen(s->password));
10283 sfree(s->password);
10286 char *str = dupprintf("No supported authentication methods available"
10287 " (server sent: %.*s)",
10290 ssh_disconnect(ssh, str,
10291 "No supported authentication methods available",
10292 SSH2_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE,
10302 ssh->packet_dispatch[SSH2_MSG_USERAUTH_BANNER] = NULL;
10304 /* Clear up various bits and pieces from authentication. */
10305 if (s->publickey_blob) {
10306 sfree(s->publickey_algorithm);
10307 sfree(s->publickey_blob);
10308 sfree(s->publickey_comment);
10310 if (s->agent_response)
10311 sfree(s->agent_response);
10313 if (s->userauth_success && !ssh->bare_connection) {
10315 * We've just received USERAUTH_SUCCESS, and we haven't sent any
10316 * packets since. Signal the transport layer to consider enacting
10317 * delayed compression.
10319 * (Relying on we_are_in is not sufficient, as
10320 * draft-miller-secsh-compression-delayed is quite clear that it
10321 * triggers on USERAUTH_SUCCESS specifically, and we_are_in can
10322 * become set for other reasons.)
10324 do_ssh2_transport(ssh, "enabling delayed compression", -2, NULL);
10327 ssh->channels = newtree234(ssh_channelcmp);
10330 * Set up handlers for some connection protocol messages, so we
10331 * don't have to handle them repeatedly in this coroutine.
10333 ssh->packet_dispatch[SSH2_MSG_CHANNEL_WINDOW_ADJUST] =
10334 ssh2_msg_channel_window_adjust;
10335 ssh->packet_dispatch[SSH2_MSG_GLOBAL_REQUEST] =
10336 ssh2_msg_global_request;
10339 * Create the main session channel.
10341 if (conf_get_int(ssh->conf, CONF_ssh_no_shell)) {
10342 ssh->mainchan = NULL;
10344 ssh->mainchan = snew(struct ssh_channel);
10345 ssh->mainchan->ssh = ssh;
10346 ssh2_channel_init(ssh->mainchan);
10348 if (*conf_get_str(ssh->conf, CONF_ssh_nc_host)) {
10350 * Just start a direct-tcpip channel and use it as the main
10353 ssh_send_port_open(ssh->mainchan,
10354 conf_get_str(ssh->conf, CONF_ssh_nc_host),
10355 conf_get_int(ssh->conf, CONF_ssh_nc_port),
10357 ssh->ncmode = TRUE;
10359 s->pktout = ssh2_chanopen_init(ssh->mainchan, "session");
10360 logevent("Opening session as main channel");
10361 ssh2_pkt_send(ssh, s->pktout);
10362 ssh->ncmode = FALSE;
10364 crWaitUntilV(pktin);
10365 if (pktin->type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
10366 bombout(("Server refused to open channel"));
10368 /* FIXME: error data comes back in FAILURE packet */
10370 if (ssh_pkt_getuint32(pktin) != ssh->mainchan->localid) {
10371 bombout(("Server's channel confirmation cited wrong channel"));
10374 ssh->mainchan->remoteid = ssh_pkt_getuint32(pktin);
10375 ssh->mainchan->halfopen = FALSE;
10376 ssh->mainchan->type = CHAN_MAINSESSION;
10377 ssh->mainchan->v.v2.remwindow = ssh_pkt_getuint32(pktin);
10378 ssh->mainchan->v.v2.remmaxpkt = ssh_pkt_getuint32(pktin);
10379 add234(ssh->channels, ssh->mainchan);
10380 update_specials_menu(ssh->frontend);
10381 logevent("Opened main channel");
10385 * Now we have a channel, make dispatch table entries for
10386 * general channel-based messages.
10388 ssh->packet_dispatch[SSH2_MSG_CHANNEL_DATA] =
10389 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EXTENDED_DATA] =
10390 ssh2_msg_channel_data;
10391 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EOF] = ssh2_msg_channel_eof;
10392 ssh->packet_dispatch[SSH2_MSG_CHANNEL_CLOSE] = ssh2_msg_channel_close;
10393 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_CONFIRMATION] =
10394 ssh2_msg_channel_open_confirmation;
10395 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_FAILURE] =
10396 ssh2_msg_channel_open_failure;
10397 ssh->packet_dispatch[SSH2_MSG_CHANNEL_REQUEST] =
10398 ssh2_msg_channel_request;
10399 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN] =
10400 ssh2_msg_channel_open;
10401 ssh->packet_dispatch[SSH2_MSG_CHANNEL_SUCCESS] = ssh2_msg_channel_response;
10402 ssh->packet_dispatch[SSH2_MSG_CHANNEL_FAILURE] = ssh2_msg_channel_response;
10405 * Now the connection protocol is properly up and running, with
10406 * all those dispatch table entries, so it's safe to let
10407 * downstreams start trying to open extra channels through us.
10409 if (ssh->connshare)
10410 share_activate(ssh->connshare, ssh->v_s);
10412 if (ssh->mainchan && ssh_is_simple(ssh)) {
10414 * This message indicates to the server that we promise
10415 * not to try to run any other channel in parallel with
10416 * this one, so it's safe for it to advertise a very large
10417 * window and leave the flow control to TCP.
10419 s->pktout = ssh2_chanreq_init(ssh->mainchan,
10420 "simple@putty.projects.tartarus.org",
10422 ssh2_pkt_send(ssh, s->pktout);
10426 * Enable port forwardings.
10428 ssh_setup_portfwd(ssh, ssh->conf);
10430 if (ssh->mainchan && !ssh->ncmode) {
10432 * Send the CHANNEL_REQUESTS for the main session channel.
10433 * Each one is handled by its own little asynchronous
10437 /* Potentially enable X11 forwarding. */
10438 if (conf_get_int(ssh->conf, CONF_x11_forward)) {
10440 x11_setup_display(conf_get_str(ssh->conf, CONF_x11_display),
10442 if (!ssh->x11disp) {
10443 /* FIXME: return an error message from x11_setup_display */
10444 logevent("X11 forwarding not enabled: unable to"
10445 " initialise X display");
10447 ssh->x11auth = x11_invent_fake_auth
10448 (ssh->x11authtree, conf_get_int(ssh->conf, CONF_x11_auth));
10449 ssh->x11auth->disp = ssh->x11disp;
10451 ssh2_setup_x11(ssh->mainchan, NULL, NULL);
10455 /* Potentially enable agent forwarding. */
10456 if (ssh_agent_forwarding_permitted(ssh))
10457 ssh2_setup_agent(ssh->mainchan, NULL, NULL);
10459 /* Now allocate a pty for the session. */
10460 if (!conf_get_int(ssh->conf, CONF_nopty))
10461 ssh2_setup_pty(ssh->mainchan, NULL, NULL);
10463 /* Send environment variables. */
10464 ssh2_setup_env(ssh->mainchan, NULL, NULL);
10467 * Start a shell or a remote command. We may have to attempt
10468 * this twice if the config data has provided a second choice
10475 if (ssh->fallback_cmd) {
10476 subsys = conf_get_int(ssh->conf, CONF_ssh_subsys2);
10477 cmd = conf_get_str(ssh->conf, CONF_remote_cmd2);
10479 subsys = conf_get_int(ssh->conf, CONF_ssh_subsys);
10480 cmd = conf_get_str(ssh->conf, CONF_remote_cmd);
10484 s->pktout = ssh2_chanreq_init(ssh->mainchan, "subsystem",
10485 ssh2_response_authconn, NULL);
10486 ssh2_pkt_addstring(s->pktout, cmd);
10488 s->pktout = ssh2_chanreq_init(ssh->mainchan, "exec",
10489 ssh2_response_authconn, NULL);
10490 ssh2_pkt_addstring(s->pktout, cmd);
10492 s->pktout = ssh2_chanreq_init(ssh->mainchan, "shell",
10493 ssh2_response_authconn, NULL);
10495 ssh2_pkt_send(ssh, s->pktout);
10497 crWaitUntilV(pktin);
10499 if (pktin->type != SSH2_MSG_CHANNEL_SUCCESS) {
10500 if (pktin->type != SSH2_MSG_CHANNEL_FAILURE) {
10501 bombout(("Unexpected response to shell/command request:"
10502 " packet type %d", pktin->type));
10506 * We failed to start the command. If this is the
10507 * fallback command, we really are finished; if it's
10508 * not, and if the fallback command exists, try falling
10509 * back to it before complaining.
10511 if (!ssh->fallback_cmd &&
10512 *conf_get_str(ssh->conf, CONF_remote_cmd2)) {
10513 logevent("Primary command failed; attempting fallback");
10514 ssh->fallback_cmd = TRUE;
10517 bombout(("Server refused to start a shell/command"));
10520 logevent("Started a shell/command");
10525 ssh->editing = ssh->echoing = TRUE;
10528 ssh->state = SSH_STATE_SESSION;
10529 if (ssh->size_needed)
10530 ssh_size(ssh, ssh->term_width, ssh->term_height);
10531 if (ssh->eof_needed)
10532 ssh_special(ssh, TS_EOF);
10538 ldisc_echoedit_update(ssh->ldisc); /* cause ldisc to notice changes */
10543 s->try_send = FALSE;
10547 * _All_ the connection-layer packets we expect to
10548 * receive are now handled by the dispatch table.
10549 * Anything that reaches here must be bogus.
10552 bombout(("Strange packet received: type %d", pktin->type));
10554 } else if (ssh->mainchan) {
10556 * We have spare data. Add it to the channel buffer.
10558 ssh2_add_channel_data(ssh->mainchan, (char *)in, inlen);
10559 s->try_send = TRUE;
10563 struct ssh_channel *c;
10565 * Try to send data on all channels if we can.
10567 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++)
10568 if (c->type != CHAN_SHARING)
10569 ssh2_try_send_and_unthrottle(ssh, c);
10577 * Handlers for SSH-2 messages that might arrive at any moment.
10579 static void ssh2_msg_disconnect(Ssh ssh, struct Packet *pktin)
10581 /* log reason code in disconnect message */
10583 int reason, msglen;
10585 reason = ssh_pkt_getuint32(pktin);
10586 ssh_pkt_getstring(pktin, &msg, &msglen);
10588 if (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) {
10589 buf = dupprintf("Received disconnect message (%s)",
10590 ssh2_disconnect_reasons[reason]);
10592 buf = dupprintf("Received disconnect message (unknown"
10593 " type %d)", reason);
10597 buf = dupprintf("Disconnection message text: %.*s",
10600 bombout(("Server sent disconnect message\ntype %d (%s):\n\"%.*s\"",
10602 (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) ?
10603 ssh2_disconnect_reasons[reason] : "unknown",
10608 static void ssh2_msg_debug(Ssh ssh, struct Packet *pktin)
10610 /* log the debug message */
10614 /* XXX maybe we should actually take notice of the return value */
10615 ssh2_pkt_getbool(pktin);
10616 ssh_pkt_getstring(pktin, &msg, &msglen);
10618 logeventf(ssh, "Remote debug message: %.*s", msglen, msg);
10621 static void ssh2_msg_transport(Ssh ssh, struct Packet *pktin)
10623 do_ssh2_transport(ssh, NULL, 0, pktin);
10627 * Called if we receive a packet that isn't allowed by the protocol.
10628 * This only applies to packets whose meaning PuTTY understands.
10629 * Entirely unknown packets are handled below.
10631 static void ssh2_msg_unexpected(Ssh ssh, struct Packet *pktin)
10633 char *buf = dupprintf("Server protocol violation: unexpected %s packet",
10634 ssh2_pkt_type(ssh->pkt_kctx, ssh->pkt_actx,
10636 ssh_disconnect(ssh, NULL, buf, SSH2_DISCONNECT_PROTOCOL_ERROR, FALSE);
10640 static void ssh2_msg_something_unimplemented(Ssh ssh, struct Packet *pktin)
10642 struct Packet *pktout;
10643 pktout = ssh2_pkt_init(SSH2_MSG_UNIMPLEMENTED);
10644 ssh2_pkt_adduint32(pktout, pktin->sequence);
10646 * UNIMPLEMENTED messages MUST appear in the same order as the
10647 * messages they respond to. Hence, never queue them.
10649 ssh2_pkt_send_noqueue(ssh, pktout);
10653 * Handle the top-level SSH-2 protocol.
10655 static void ssh2_protocol_setup(Ssh ssh)
10660 * Most messages cause SSH2_MSG_UNIMPLEMENTED.
10662 for (i = 0; i < 256; i++)
10663 ssh->packet_dispatch[i] = ssh2_msg_something_unimplemented;
10666 * Initially, we only accept transport messages (and a few generic
10667 * ones). do_ssh2_authconn will add more when it starts.
10668 * Messages that are understood but not currently acceptable go to
10669 * ssh2_msg_unexpected.
10671 ssh->packet_dispatch[SSH2_MSG_UNIMPLEMENTED] = ssh2_msg_unexpected;
10672 ssh->packet_dispatch[SSH2_MSG_SERVICE_REQUEST] = ssh2_msg_unexpected;
10673 ssh->packet_dispatch[SSH2_MSG_SERVICE_ACCEPT] = ssh2_msg_unexpected;
10674 ssh->packet_dispatch[SSH2_MSG_KEXINIT] = ssh2_msg_transport;
10675 ssh->packet_dispatch[SSH2_MSG_NEWKEYS] = ssh2_msg_transport;
10676 ssh->packet_dispatch[SSH2_MSG_KEXDH_INIT] = ssh2_msg_transport;
10677 ssh->packet_dispatch[SSH2_MSG_KEXDH_REPLY] = ssh2_msg_transport;
10678 /* ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_REQUEST] = ssh2_msg_transport; duplicate case value */
10679 /* ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_GROUP] = ssh2_msg_transport; duplicate case value */
10680 ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_INIT] = ssh2_msg_transport;
10681 ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_REPLY] = ssh2_msg_transport;
10682 ssh->packet_dispatch[SSH2_MSG_USERAUTH_REQUEST] = ssh2_msg_unexpected;
10683 ssh->packet_dispatch[SSH2_MSG_USERAUTH_FAILURE] = ssh2_msg_unexpected;
10684 ssh->packet_dispatch[SSH2_MSG_USERAUTH_SUCCESS] = ssh2_msg_unexpected;
10685 ssh->packet_dispatch[SSH2_MSG_USERAUTH_BANNER] = ssh2_msg_unexpected;
10686 ssh->packet_dispatch[SSH2_MSG_USERAUTH_PK_OK] = ssh2_msg_unexpected;
10687 /* ssh->packet_dispatch[SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ] = ssh2_msg_unexpected; duplicate case value */
10688 /* ssh->packet_dispatch[SSH2_MSG_USERAUTH_INFO_REQUEST] = ssh2_msg_unexpected; duplicate case value */
10689 ssh->packet_dispatch[SSH2_MSG_USERAUTH_INFO_RESPONSE] = ssh2_msg_unexpected;
10690 ssh->packet_dispatch[SSH2_MSG_GLOBAL_REQUEST] = ssh2_msg_unexpected;
10691 ssh->packet_dispatch[SSH2_MSG_REQUEST_SUCCESS] = ssh2_msg_unexpected;
10692 ssh->packet_dispatch[SSH2_MSG_REQUEST_FAILURE] = ssh2_msg_unexpected;
10693 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN] = ssh2_msg_unexpected;
10694 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_CONFIRMATION] = ssh2_msg_unexpected;
10695 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_FAILURE] = ssh2_msg_unexpected;
10696 ssh->packet_dispatch[SSH2_MSG_CHANNEL_WINDOW_ADJUST] = ssh2_msg_unexpected;
10697 ssh->packet_dispatch[SSH2_MSG_CHANNEL_DATA] = ssh2_msg_unexpected;
10698 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EXTENDED_DATA] = ssh2_msg_unexpected;
10699 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EOF] = ssh2_msg_unexpected;
10700 ssh->packet_dispatch[SSH2_MSG_CHANNEL_CLOSE] = ssh2_msg_unexpected;
10701 ssh->packet_dispatch[SSH2_MSG_CHANNEL_REQUEST] = ssh2_msg_unexpected;
10702 ssh->packet_dispatch[SSH2_MSG_CHANNEL_SUCCESS] = ssh2_msg_unexpected;
10703 ssh->packet_dispatch[SSH2_MSG_CHANNEL_FAILURE] = ssh2_msg_unexpected;
10706 * These messages have a special handler from the start.
10708 ssh->packet_dispatch[SSH2_MSG_DISCONNECT] = ssh2_msg_disconnect;
10709 ssh->packet_dispatch[SSH2_MSG_IGNORE] = ssh_msg_ignore; /* shared with SSH-1 */
10710 ssh->packet_dispatch[SSH2_MSG_DEBUG] = ssh2_msg_debug;
10713 static void ssh2_bare_connection_protocol_setup(Ssh ssh)
10718 * Most messages cause SSH2_MSG_UNIMPLEMENTED.
10720 for (i = 0; i < 256; i++)
10721 ssh->packet_dispatch[i] = ssh2_msg_something_unimplemented;
10724 * Initially, we set all ssh-connection messages to 'unexpected';
10725 * do_ssh2_authconn will fill things in properly. We also handle a
10726 * couple of messages from the transport protocol which aren't
10727 * related to key exchange (UNIMPLEMENTED, IGNORE, DEBUG,
10730 ssh->packet_dispatch[SSH2_MSG_GLOBAL_REQUEST] = ssh2_msg_unexpected;
10731 ssh->packet_dispatch[SSH2_MSG_REQUEST_SUCCESS] = ssh2_msg_unexpected;
10732 ssh->packet_dispatch[SSH2_MSG_REQUEST_FAILURE] = ssh2_msg_unexpected;
10733 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN] = ssh2_msg_unexpected;
10734 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_CONFIRMATION] = ssh2_msg_unexpected;
10735 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_FAILURE] = ssh2_msg_unexpected;
10736 ssh->packet_dispatch[SSH2_MSG_CHANNEL_WINDOW_ADJUST] = ssh2_msg_unexpected;
10737 ssh->packet_dispatch[SSH2_MSG_CHANNEL_DATA] = ssh2_msg_unexpected;
10738 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EXTENDED_DATA] = ssh2_msg_unexpected;
10739 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EOF] = ssh2_msg_unexpected;
10740 ssh->packet_dispatch[SSH2_MSG_CHANNEL_CLOSE] = ssh2_msg_unexpected;
10741 ssh->packet_dispatch[SSH2_MSG_CHANNEL_REQUEST] = ssh2_msg_unexpected;
10742 ssh->packet_dispatch[SSH2_MSG_CHANNEL_SUCCESS] = ssh2_msg_unexpected;
10743 ssh->packet_dispatch[SSH2_MSG_CHANNEL_FAILURE] = ssh2_msg_unexpected;
10745 ssh->packet_dispatch[SSH2_MSG_UNIMPLEMENTED] = ssh2_msg_unexpected;
10748 * These messages have a special handler from the start.
10750 ssh->packet_dispatch[SSH2_MSG_DISCONNECT] = ssh2_msg_disconnect;
10751 ssh->packet_dispatch[SSH2_MSG_IGNORE] = ssh_msg_ignore;
10752 ssh->packet_dispatch[SSH2_MSG_DEBUG] = ssh2_msg_debug;
10755 static void ssh2_timer(void *ctx, unsigned long now)
10757 Ssh ssh = (Ssh)ctx;
10759 if (ssh->state == SSH_STATE_CLOSED)
10762 if (!ssh->kex_in_progress && !ssh->bare_connection &&
10763 conf_get_int(ssh->conf, CONF_ssh_rekey_time) != 0 &&
10764 now == ssh->next_rekey) {
10765 do_ssh2_transport(ssh, "timeout", -1, NULL);
10769 static void ssh2_protocol(Ssh ssh, const void *vin, int inlen,
10770 struct Packet *pktin)
10772 const unsigned char *in = (const unsigned char *)vin;
10773 if (ssh->state == SSH_STATE_CLOSED)
10777 ssh->incoming_data_size += pktin->encrypted_len;
10778 if (!ssh->kex_in_progress &&
10779 ssh->max_data_size != 0 &&
10780 ssh->incoming_data_size > ssh->max_data_size)
10781 do_ssh2_transport(ssh, "too much data received", -1, NULL);
10785 ssh->packet_dispatch[pktin->type](ssh, pktin);
10786 else if (!ssh->protocol_initial_phase_done)
10787 do_ssh2_transport(ssh, in, inlen, pktin);
10789 do_ssh2_authconn(ssh, in, inlen, pktin);
10792 static void ssh2_bare_connection_protocol(Ssh ssh, const void *vin, int inlen,
10793 struct Packet *pktin)
10795 const unsigned char *in = (const unsigned char *)vin;
10796 if (ssh->state == SSH_STATE_CLOSED)
10800 ssh->packet_dispatch[pktin->type](ssh, pktin);
10802 do_ssh2_authconn(ssh, in, inlen, pktin);
10805 static void ssh_cache_conf_values(Ssh ssh)
10807 ssh->logomitdata = conf_get_int(ssh->conf, CONF_logomitdata);
10811 * Called to set up the connection.
10813 * Returns an error message, or NULL on success.
10815 static const char *ssh_init(void *frontend_handle, void **backend_handle,
10817 const char *host, int port, char **realhost,
10818 int nodelay, int keepalive)
10823 ssh = snew(struct ssh_tag);
10824 ssh->conf = conf_copy(conf);
10825 ssh_cache_conf_values(ssh);
10826 ssh->version = 0; /* when not ready yet */
10828 ssh->cipher = NULL;
10829 ssh->v1_cipher_ctx = NULL;
10830 ssh->crcda_ctx = NULL;
10831 ssh->cscipher = NULL;
10832 ssh->cs_cipher_ctx = NULL;
10833 ssh->sccipher = NULL;
10834 ssh->sc_cipher_ctx = NULL;
10836 ssh->cs_mac_ctx = NULL;
10838 ssh->sc_mac_ctx = NULL;
10839 ssh->cscomp = NULL;
10840 ssh->cs_comp_ctx = NULL;
10841 ssh->sccomp = NULL;
10842 ssh->sc_comp_ctx = NULL;
10844 ssh->kex_ctx = NULL;
10845 ssh->hostkey = NULL;
10846 ssh->hostkey_str = NULL;
10847 ssh->exitcode = -1;
10848 ssh->close_expected = FALSE;
10849 ssh->clean_exit = FALSE;
10850 ssh->state = SSH_STATE_PREPACKET;
10851 ssh->size_needed = FALSE;
10852 ssh->eof_needed = FALSE;
10854 ssh->logctx = NULL;
10855 ssh->deferred_send_data = NULL;
10856 ssh->deferred_len = 0;
10857 ssh->deferred_size = 0;
10858 ssh->fallback_cmd = 0;
10859 ssh->pkt_kctx = SSH2_PKTCTX_NOKEX;
10860 ssh->pkt_actx = SSH2_PKTCTX_NOAUTH;
10861 ssh->x11disp = NULL;
10862 ssh->x11auth = NULL;
10863 ssh->x11authtree = newtree234(x11_authcmp);
10864 ssh->v1_compressing = FALSE;
10865 ssh->v2_outgoing_sequence = 0;
10866 ssh->ssh1_rdpkt_crstate = 0;
10867 ssh->ssh2_rdpkt_crstate = 0;
10868 ssh->ssh2_bare_rdpkt_crstate = 0;
10869 ssh->ssh_gotdata_crstate = 0;
10870 ssh->do_ssh1_connection_crstate = 0;
10871 ssh->do_ssh_init_state = NULL;
10872 ssh->do_ssh_connection_init_state = NULL;
10873 ssh->do_ssh1_login_state = NULL;
10874 ssh->do_ssh2_transport_state = NULL;
10875 ssh->do_ssh2_authconn_state = NULL;
10878 ssh->mainchan = NULL;
10879 ssh->throttled_all = 0;
10880 ssh->v1_stdout_throttling = 0;
10882 ssh->queuelen = ssh->queuesize = 0;
10883 ssh->queueing = FALSE;
10884 ssh->qhead = ssh->qtail = NULL;
10885 ssh->deferred_rekey_reason = NULL;
10886 bufchain_init(&ssh->queued_incoming_data);
10887 ssh->frozen = FALSE;
10888 ssh->username = NULL;
10889 ssh->sent_console_eof = FALSE;
10890 ssh->got_pty = FALSE;
10891 ssh->bare_connection = FALSE;
10892 ssh->X11_fwd_enabled = FALSE;
10893 ssh->connshare = NULL;
10894 ssh->attempting_connshare = FALSE;
10896 *backend_handle = ssh;
10899 if (crypto_startup() == 0)
10900 return "Microsoft high encryption pack not installed!";
10903 ssh->frontend = frontend_handle;
10904 ssh->term_width = conf_get_int(ssh->conf, CONF_width);
10905 ssh->term_height = conf_get_int(ssh->conf, CONF_height);
10907 ssh->channels = NULL;
10908 ssh->rportfwds = NULL;
10909 ssh->portfwds = NULL;
10914 ssh->conn_throttle_count = 0;
10915 ssh->overall_bufsize = 0;
10916 ssh->fallback_cmd = 0;
10918 ssh->protocol = NULL;
10920 ssh->protocol_initial_phase_done = FALSE;
10922 ssh->pinger = NULL;
10924 ssh->incoming_data_size = ssh->outgoing_data_size =
10925 ssh->deferred_data_size = 0L;
10926 ssh->max_data_size = parse_blocksize(conf_get_str(ssh->conf,
10927 CONF_ssh_rekey_data));
10928 ssh->kex_in_progress = FALSE;
10931 ssh->gsslibs = NULL;
10934 random_ref(); /* do this now - may be needed by sharing setup code */
10936 p = connect_to_host(ssh, host, port, realhost, nodelay, keepalive);
10945 static void ssh_free(void *handle)
10947 Ssh ssh = (Ssh) handle;
10948 struct ssh_channel *c;
10949 struct ssh_rportfwd *pf;
10950 struct X11FakeAuth *auth;
10952 if (ssh->v1_cipher_ctx)
10953 ssh->cipher->free_context(ssh->v1_cipher_ctx);
10954 if (ssh->cs_cipher_ctx)
10955 ssh->cscipher->free_context(ssh->cs_cipher_ctx);
10956 if (ssh->sc_cipher_ctx)
10957 ssh->sccipher->free_context(ssh->sc_cipher_ctx);
10958 if (ssh->cs_mac_ctx)
10959 ssh->csmac->free_context(ssh->cs_mac_ctx);
10960 if (ssh->sc_mac_ctx)
10961 ssh->scmac->free_context(ssh->sc_mac_ctx);
10962 if (ssh->cs_comp_ctx) {
10964 ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
10966 zlib_compress_cleanup(ssh->cs_comp_ctx);
10968 if (ssh->sc_comp_ctx) {
10970 ssh->sccomp->decompress_cleanup(ssh->sc_comp_ctx);
10972 zlib_decompress_cleanup(ssh->sc_comp_ctx);
10975 dh_cleanup(ssh->kex_ctx);
10976 sfree(ssh->savedhost);
10978 while (ssh->queuelen-- > 0)
10979 ssh_free_packet(ssh->queue[ssh->queuelen]);
10982 while (ssh->qhead) {
10983 struct queued_handler *qh = ssh->qhead;
10984 ssh->qhead = qh->next;
10987 ssh->qhead = ssh->qtail = NULL;
10989 if (ssh->channels) {
10990 while ((c = delpos234(ssh->channels, 0)) != NULL) {
10993 if (c->u.x11.xconn != NULL)
10994 x11_close(c->u.x11.xconn);
10996 case CHAN_SOCKDATA:
10997 case CHAN_SOCKDATA_DORMANT:
10998 if (c->u.pfd.pf != NULL)
10999 pfd_close(c->u.pfd.pf);
11002 if (ssh->version == 2) {
11003 struct outstanding_channel_request *ocr, *nocr;
11004 ocr = c->v.v2.chanreq_head;
11006 ocr->handler(c, NULL, ocr->ctx);
11011 bufchain_clear(&c->v.v2.outbuffer);
11015 freetree234(ssh->channels);
11016 ssh->channels = NULL;
11019 if (ssh->connshare)
11020 sharestate_free(ssh->connshare);
11022 if (ssh->rportfwds) {
11023 while ((pf = delpos234(ssh->rportfwds, 0)) != NULL)
11025 freetree234(ssh->rportfwds);
11026 ssh->rportfwds = NULL;
11028 sfree(ssh->deferred_send_data);
11030 x11_free_display(ssh->x11disp);
11031 while ((auth = delpos234(ssh->x11authtree, 0)) != NULL)
11032 x11_free_fake_auth(auth);
11033 freetree234(ssh->x11authtree);
11034 sfree(ssh->do_ssh_init_state);
11035 sfree(ssh->do_ssh1_login_state);
11036 sfree(ssh->do_ssh2_transport_state);
11037 sfree(ssh->do_ssh2_authconn_state);
11040 sfree(ssh->fullhostname);
11041 sfree(ssh->hostkey_str);
11042 if (ssh->crcda_ctx) {
11043 crcda_free_context(ssh->crcda_ctx);
11044 ssh->crcda_ctx = NULL;
11047 ssh_do_close(ssh, TRUE);
11048 expire_timer_context(ssh);
11050 pinger_free(ssh->pinger);
11051 bufchain_clear(&ssh->queued_incoming_data);
11052 sfree(ssh->username);
11053 conf_free(ssh->conf);
11056 ssh_gss_cleanup(ssh->gsslibs);
11064 * Reconfigure the SSH backend.
11066 static void ssh_reconfig(void *handle, Conf *conf)
11068 Ssh ssh = (Ssh) handle;
11069 const char *rekeying = NULL;
11070 int rekey_mandatory = FALSE;
11071 unsigned long old_max_data_size;
11074 pinger_reconfig(ssh->pinger, ssh->conf, conf);
11076 ssh_setup_portfwd(ssh, conf);
11078 rekey_time = conf_get_int(conf, CONF_ssh_rekey_time);
11079 if (conf_get_int(ssh->conf, CONF_ssh_rekey_time) != rekey_time &&
11081 unsigned long new_next = ssh->last_rekey + rekey_time*60*TICKSPERSEC;
11082 unsigned long now = GETTICKCOUNT();
11084 if (now - ssh->last_rekey > rekey_time*60*TICKSPERSEC) {
11085 rekeying = "timeout shortened";
11087 ssh->next_rekey = schedule_timer(new_next - now, ssh2_timer, ssh);
11091 old_max_data_size = ssh->max_data_size;
11092 ssh->max_data_size = parse_blocksize(conf_get_str(ssh->conf,
11093 CONF_ssh_rekey_data));
11094 if (old_max_data_size != ssh->max_data_size &&
11095 ssh->max_data_size != 0) {
11096 if (ssh->outgoing_data_size > ssh->max_data_size ||
11097 ssh->incoming_data_size > ssh->max_data_size)
11098 rekeying = "data limit lowered";
11101 if (conf_get_int(ssh->conf, CONF_compression) !=
11102 conf_get_int(conf, CONF_compression)) {
11103 rekeying = "compression setting changed";
11104 rekey_mandatory = TRUE;
11107 for (i = 0; i < CIPHER_MAX; i++)
11108 if (conf_get_int_int(ssh->conf, CONF_ssh_cipherlist, i) !=
11109 conf_get_int_int(conf, CONF_ssh_cipherlist, i)) {
11110 rekeying = "cipher settings changed";
11111 rekey_mandatory = TRUE;
11113 if (conf_get_int(ssh->conf, CONF_ssh2_des_cbc) !=
11114 conf_get_int(conf, CONF_ssh2_des_cbc)) {
11115 rekeying = "cipher settings changed";
11116 rekey_mandatory = TRUE;
11119 conf_free(ssh->conf);
11120 ssh->conf = conf_copy(conf);
11121 ssh_cache_conf_values(ssh);
11123 if (!ssh->bare_connection && rekeying) {
11124 if (!ssh->kex_in_progress) {
11125 do_ssh2_transport(ssh, rekeying, -1, NULL);
11126 } else if (rekey_mandatory) {
11127 ssh->deferred_rekey_reason = rekeying;
11133 * Called to send data down the SSH connection.
11135 static int ssh_send(void *handle, const char *buf, int len)
11137 Ssh ssh = (Ssh) handle;
11139 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
11142 ssh->protocol(ssh, (const unsigned char *)buf, len, 0);
11144 return ssh_sendbuffer(ssh);
11148 * Called to query the current amount of buffered stdin data.
11150 static int ssh_sendbuffer(void *handle)
11152 Ssh ssh = (Ssh) handle;
11153 int override_value;
11155 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
11159 * If the SSH socket itself has backed up, add the total backup
11160 * size on that to any individual buffer on the stdin channel.
11162 override_value = 0;
11163 if (ssh->throttled_all)
11164 override_value = ssh->overall_bufsize;
11166 if (ssh->version == 1) {
11167 return override_value;
11168 } else if (ssh->version == 2) {
11169 if (!ssh->mainchan)
11170 return override_value;
11172 return (override_value +
11173 bufchain_size(&ssh->mainchan->v.v2.outbuffer));
11180 * Called to set the size of the window from SSH's POV.
11182 static void ssh_size(void *handle, int width, int height)
11184 Ssh ssh = (Ssh) handle;
11185 struct Packet *pktout;
11187 ssh->term_width = width;
11188 ssh->term_height = height;
11190 switch (ssh->state) {
11191 case SSH_STATE_BEFORE_SIZE:
11192 case SSH_STATE_PREPACKET:
11193 case SSH_STATE_CLOSED:
11194 break; /* do nothing */
11195 case SSH_STATE_INTERMED:
11196 ssh->size_needed = TRUE; /* buffer for later */
11198 case SSH_STATE_SESSION:
11199 if (!conf_get_int(ssh->conf, CONF_nopty)) {
11200 if (ssh->version == 1) {
11201 send_packet(ssh, SSH1_CMSG_WINDOW_SIZE,
11202 PKT_INT, ssh->term_height,
11203 PKT_INT, ssh->term_width,
11204 PKT_INT, 0, PKT_INT, 0, PKT_END);
11205 } else if (ssh->mainchan) {
11206 pktout = ssh2_chanreq_init(ssh->mainchan, "window-change",
11208 ssh2_pkt_adduint32(pktout, ssh->term_width);
11209 ssh2_pkt_adduint32(pktout, ssh->term_height);
11210 ssh2_pkt_adduint32(pktout, 0);
11211 ssh2_pkt_adduint32(pktout, 0);
11212 ssh2_pkt_send(ssh, pktout);
11220 * Return a list of the special codes that make sense in this
11223 static const struct telnet_special *ssh_get_specials(void *handle)
11225 static const struct telnet_special ssh1_ignore_special[] = {
11226 {"IGNORE message", TS_NOP}
11228 static const struct telnet_special ssh2_ignore_special[] = {
11229 {"IGNORE message", TS_NOP},
11231 static const struct telnet_special ssh2_rekey_special[] = {
11232 {"Repeat key exchange", TS_REKEY},
11234 static const struct telnet_special ssh2_session_specials[] = {
11237 /* These are the signal names defined by RFC 4254.
11238 * They include all the ISO C signals, but are a subset of the POSIX
11239 * required signals. */
11240 {"SIGINT (Interrupt)", TS_SIGINT},
11241 {"SIGTERM (Terminate)", TS_SIGTERM},
11242 {"SIGKILL (Kill)", TS_SIGKILL},
11243 {"SIGQUIT (Quit)", TS_SIGQUIT},
11244 {"SIGHUP (Hangup)", TS_SIGHUP},
11245 {"More signals", TS_SUBMENU},
11246 {"SIGABRT", TS_SIGABRT}, {"SIGALRM", TS_SIGALRM},
11247 {"SIGFPE", TS_SIGFPE}, {"SIGILL", TS_SIGILL},
11248 {"SIGPIPE", TS_SIGPIPE}, {"SIGSEGV", TS_SIGSEGV},
11249 {"SIGUSR1", TS_SIGUSR1}, {"SIGUSR2", TS_SIGUSR2},
11250 {NULL, TS_EXITMENU}
11252 static const struct telnet_special specials_end[] = {
11253 {NULL, TS_EXITMENU}
11255 /* XXX review this length for any changes: */
11256 static struct telnet_special ssh_specials[lenof(ssh2_ignore_special) +
11257 lenof(ssh2_rekey_special) +
11258 lenof(ssh2_session_specials) +
11259 lenof(specials_end)];
11260 Ssh ssh = (Ssh) handle;
11262 #define ADD_SPECIALS(name) \
11264 assert((i + lenof(name)) <= lenof(ssh_specials)); \
11265 memcpy(&ssh_specials[i], name, sizeof name); \
11266 i += lenof(name); \
11269 if (ssh->version == 1) {
11270 /* Don't bother offering IGNORE if we've decided the remote
11271 * won't cope with it, since we wouldn't bother sending it if
11273 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE))
11274 ADD_SPECIALS(ssh1_ignore_special);
11275 } else if (ssh->version == 2) {
11276 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH2_IGNORE))
11277 ADD_SPECIALS(ssh2_ignore_special);
11278 if (!(ssh->remote_bugs & BUG_SSH2_REKEY) && !ssh->bare_connection)
11279 ADD_SPECIALS(ssh2_rekey_special);
11281 ADD_SPECIALS(ssh2_session_specials);
11282 } /* else we're not ready yet */
11285 ADD_SPECIALS(specials_end);
11286 return ssh_specials;
11290 #undef ADD_SPECIALS
11294 * Send special codes. TS_EOF is useful for `plink', so you
11295 * can send an EOF and collect resulting output (e.g. `plink
11298 static void ssh_special(void *handle, Telnet_Special code)
11300 Ssh ssh = (Ssh) handle;
11301 struct Packet *pktout;
11303 if (code == TS_EOF) {
11304 if (ssh->state != SSH_STATE_SESSION) {
11306 * Buffer the EOF in case we are pre-SESSION, so we can
11307 * send it as soon as we reach SESSION.
11309 if (code == TS_EOF)
11310 ssh->eof_needed = TRUE;
11313 if (ssh->version == 1) {
11314 send_packet(ssh, SSH1_CMSG_EOF, PKT_END);
11315 } else if (ssh->mainchan) {
11316 sshfwd_write_eof(ssh->mainchan);
11317 ssh->send_ok = 0; /* now stop trying to read from stdin */
11319 logevent("Sent EOF message");
11320 } else if (code == TS_PING || code == TS_NOP) {
11321 if (ssh->state == SSH_STATE_CLOSED
11322 || ssh->state == SSH_STATE_PREPACKET) return;
11323 if (ssh->version == 1) {
11324 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE))
11325 send_packet(ssh, SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
11327 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH2_IGNORE)) {
11328 pktout = ssh2_pkt_init(SSH2_MSG_IGNORE);
11329 ssh2_pkt_addstring_start(pktout);
11330 ssh2_pkt_send_noqueue(ssh, pktout);
11333 } else if (code == TS_REKEY) {
11334 if (!ssh->kex_in_progress && !ssh->bare_connection &&
11335 ssh->version == 2) {
11336 do_ssh2_transport(ssh, "at user request", -1, NULL);
11338 } else if (code == TS_BRK) {
11339 if (ssh->state == SSH_STATE_CLOSED
11340 || ssh->state == SSH_STATE_PREPACKET) return;
11341 if (ssh->version == 1) {
11342 logevent("Unable to send BREAK signal in SSH-1");
11343 } else if (ssh->mainchan) {
11344 pktout = ssh2_chanreq_init(ssh->mainchan, "break", NULL, NULL);
11345 ssh2_pkt_adduint32(pktout, 0); /* default break length */
11346 ssh2_pkt_send(ssh, pktout);
11349 /* Is is a POSIX signal? */
11350 const char *signame = NULL;
11351 if (code == TS_SIGABRT) signame = "ABRT";
11352 if (code == TS_SIGALRM) signame = "ALRM";
11353 if (code == TS_SIGFPE) signame = "FPE";
11354 if (code == TS_SIGHUP) signame = "HUP";
11355 if (code == TS_SIGILL) signame = "ILL";
11356 if (code == TS_SIGINT) signame = "INT";
11357 if (code == TS_SIGKILL) signame = "KILL";
11358 if (code == TS_SIGPIPE) signame = "PIPE";
11359 if (code == TS_SIGQUIT) signame = "QUIT";
11360 if (code == TS_SIGSEGV) signame = "SEGV";
11361 if (code == TS_SIGTERM) signame = "TERM";
11362 if (code == TS_SIGUSR1) signame = "USR1";
11363 if (code == TS_SIGUSR2) signame = "USR2";
11364 /* The SSH-2 protocol does in principle support arbitrary named
11365 * signals, including signame@domain, but we don't support those. */
11367 /* It's a signal. */
11368 if (ssh->version == 2 && ssh->mainchan) {
11369 pktout = ssh2_chanreq_init(ssh->mainchan, "signal", NULL, NULL);
11370 ssh2_pkt_addstring(pktout, signame);
11371 ssh2_pkt_send(ssh, pktout);
11372 logeventf(ssh, "Sent signal SIG%s", signame);
11375 /* Never heard of it. Do nothing */
11380 void *new_sock_channel(void *handle, struct PortForwarding *pf)
11382 Ssh ssh = (Ssh) handle;
11383 struct ssh_channel *c;
11384 c = snew(struct ssh_channel);
11387 ssh2_channel_init(c);
11388 c->halfopen = TRUE;
11389 c->type = CHAN_SOCKDATA_DORMANT;/* identify channel type */
11391 add234(ssh->channels, c);
11395 unsigned ssh_alloc_sharing_channel(Ssh ssh, void *sharing_ctx)
11397 struct ssh_channel *c;
11398 c = snew(struct ssh_channel);
11401 ssh2_channel_init(c);
11402 c->type = CHAN_SHARING;
11403 c->u.sharing.ctx = sharing_ctx;
11404 add234(ssh->channels, c);
11408 void ssh_delete_sharing_channel(Ssh ssh, unsigned localid)
11410 struct ssh_channel *c;
11412 c = find234(ssh->channels, &localid, ssh_channelfind);
11414 ssh_channel_destroy(c);
11417 void ssh_send_packet_from_downstream(Ssh ssh, unsigned id, int type,
11418 const void *data, int datalen,
11419 const char *additional_log_text)
11421 struct Packet *pkt;
11423 pkt = ssh2_pkt_init(type);
11424 pkt->downstream_id = id;
11425 pkt->additional_log_text = additional_log_text;
11426 ssh2_pkt_adddata(pkt, data, datalen);
11427 ssh2_pkt_send(ssh, pkt);
11431 * This is called when stdout/stderr (the entity to which
11432 * from_backend sends data) manages to clear some backlog.
11434 static void ssh_unthrottle(void *handle, int bufsize)
11436 Ssh ssh = (Ssh) handle;
11439 if (ssh->version == 1) {
11440 if (ssh->v1_stdout_throttling && bufsize < SSH1_BUFFER_LIMIT) {
11441 ssh->v1_stdout_throttling = 0;
11442 ssh_throttle_conn(ssh, -1);
11445 if (ssh->mainchan) {
11446 ssh2_set_window(ssh->mainchan,
11447 bufsize < ssh->mainchan->v.v2.locmaxwin ?
11448 ssh->mainchan->v.v2.locmaxwin - bufsize : 0);
11449 if (ssh_is_simple(ssh))
11452 buflimit = ssh->mainchan->v.v2.locmaxwin;
11453 if (ssh->mainchan->throttling_conn && bufsize <= buflimit) {
11454 ssh->mainchan->throttling_conn = 0;
11455 ssh_throttle_conn(ssh, -1);
11461 * Now process any SSH connection data that was stashed in our
11462 * queue while we were frozen.
11464 ssh_process_queued_incoming_data(ssh);
11467 void ssh_send_port_open(void *channel, const char *hostname, int port,
11470 struct ssh_channel *c = (struct ssh_channel *)channel;
11472 struct Packet *pktout;
11474 logeventf(ssh, "Opening connection to %s:%d for %s", hostname, port, org);
11476 if (ssh->version == 1) {
11477 send_packet(ssh, SSH1_MSG_PORT_OPEN,
11478 PKT_INT, c->localid,
11481 /* PKT_STR, <org:orgport>, */
11484 pktout = ssh2_chanopen_init(c, "direct-tcpip");
11486 char *trimmed_host = host_strduptrim(hostname);
11487 ssh2_pkt_addstring(pktout, trimmed_host);
11488 sfree(trimmed_host);
11490 ssh2_pkt_adduint32(pktout, port);
11492 * We make up values for the originator data; partly it's
11493 * too much hassle to keep track, and partly I'm not
11494 * convinced the server should be told details like that
11495 * about my local network configuration.
11496 * The "originator IP address" is syntactically a numeric
11497 * IP address, and some servers (e.g., Tectia) get upset
11498 * if it doesn't match this syntax.
11500 ssh2_pkt_addstring(pktout, "0.0.0.0");
11501 ssh2_pkt_adduint32(pktout, 0);
11502 ssh2_pkt_send(ssh, pktout);
11506 static int ssh_connected(void *handle)
11508 Ssh ssh = (Ssh) handle;
11509 return ssh->s != NULL;
11512 static int ssh_sendok(void *handle)
11514 Ssh ssh = (Ssh) handle;
11515 return ssh->send_ok;
11518 static int ssh_ldisc(void *handle, int option)
11520 Ssh ssh = (Ssh) handle;
11521 if (option == LD_ECHO)
11522 return ssh->echoing;
11523 if (option == LD_EDIT)
11524 return ssh->editing;
11528 static void ssh_provide_ldisc(void *handle, void *ldisc)
11530 Ssh ssh = (Ssh) handle;
11531 ssh->ldisc = ldisc;
11534 static void ssh_provide_logctx(void *handle, void *logctx)
11536 Ssh ssh = (Ssh) handle;
11537 ssh->logctx = logctx;
11540 static int ssh_return_exitcode(void *handle)
11542 Ssh ssh = (Ssh) handle;
11543 if (ssh->s != NULL)
11546 return (ssh->exitcode >= 0 ? ssh->exitcode : INT_MAX);
11550 * cfg_info for SSH is the protocol running in this session.
11551 * (1 or 2 for the full SSH-1 or SSH-2 protocol; -1 for the bare
11552 * SSH-2 connection protocol, i.e. a downstream; 0 for not-decided-yet.)
11554 static int ssh_cfg_info(void *handle)
11556 Ssh ssh = (Ssh) handle;
11557 if (ssh->version == 0)
11558 return 0; /* don't know yet */
11559 else if (ssh->bare_connection)
11562 return ssh->version;
11566 * Gross hack: pscp will try to start SFTP but fall back to scp1 if
11567 * that fails. This variable is the means by which scp.c can reach
11568 * into the SSH code and find out which one it got.
11570 extern int ssh_fallback_cmd(void *handle)
11572 Ssh ssh = (Ssh) handle;
11573 return ssh->fallback_cmd;
11576 Backend ssh_backend = {
11586 ssh_return_exitcode,
11590 ssh_provide_logctx,