28 * Packet type contexts, so that ssh2_pkt_type can correctly decode
29 * the ambiguous type numbers back into the correct type strings.
40 SSH2_PKTCTX_PUBLICKEY,
46 static const char *const ssh2_disconnect_reasons[] = {
48 "host not allowed to connect",
50 "key exchange failed",
51 "host authentication failed",
54 "service not available",
55 "protocol version not supported",
56 "host key not verifiable",
59 "too many connections",
60 "auth cancelled by user",
61 "no more auth methods available",
66 * Various remote-bug flags.
68 #define BUG_CHOKES_ON_SSH1_IGNORE 1
69 #define BUG_SSH2_HMAC 2
70 #define BUG_NEEDS_SSH1_PLAIN_PASSWORD 4
71 #define BUG_CHOKES_ON_RSA 8
72 #define BUG_SSH2_RSA_PADDING 16
73 #define BUG_SSH2_DERIVEKEY 32
74 #define BUG_SSH2_REKEY 64
75 #define BUG_SSH2_PK_SESSIONID 128
76 #define BUG_SSH2_MAXPKT 256
77 #define BUG_CHOKES_ON_SSH2_IGNORE 512
78 #define BUG_CHOKES_ON_WINADJ 1024
79 #define BUG_SENDS_LATE_REQUEST_REPLY 2048
80 #define BUG_SSH2_OLDGEX 4096
82 #define DH_MIN_SIZE 1024
83 #define DH_MAX_SIZE 8192
86 * Codes for terminal modes.
87 * Most of these are the same in SSH-1 and SSH-2.
88 * This list is derived from RFC 4254 and
92 const char* const mode;
94 enum { TTY_OP_CHAR, TTY_OP_BOOL } type;
96 /* "V" prefix discarded for special characters relative to SSH specs */
97 { "INTR", 1, TTY_OP_CHAR },
98 { "QUIT", 2, TTY_OP_CHAR },
99 { "ERASE", 3, TTY_OP_CHAR },
100 { "KILL", 4, TTY_OP_CHAR },
101 { "EOF", 5, TTY_OP_CHAR },
102 { "EOL", 6, TTY_OP_CHAR },
103 { "EOL2", 7, TTY_OP_CHAR },
104 { "START", 8, TTY_OP_CHAR },
105 { "STOP", 9, TTY_OP_CHAR },
106 { "SUSP", 10, TTY_OP_CHAR },
107 { "DSUSP", 11, TTY_OP_CHAR },
108 { "REPRINT", 12, TTY_OP_CHAR },
109 { "WERASE", 13, TTY_OP_CHAR },
110 { "LNEXT", 14, TTY_OP_CHAR },
111 { "FLUSH", 15, TTY_OP_CHAR },
112 { "SWTCH", 16, TTY_OP_CHAR },
113 { "STATUS", 17, TTY_OP_CHAR },
114 { "DISCARD", 18, TTY_OP_CHAR },
115 { "IGNPAR", 30, TTY_OP_BOOL },
116 { "PARMRK", 31, TTY_OP_BOOL },
117 { "INPCK", 32, TTY_OP_BOOL },
118 { "ISTRIP", 33, TTY_OP_BOOL },
119 { "INLCR", 34, TTY_OP_BOOL },
120 { "IGNCR", 35, TTY_OP_BOOL },
121 { "ICRNL", 36, TTY_OP_BOOL },
122 { "IUCLC", 37, TTY_OP_BOOL },
123 { "IXON", 38, TTY_OP_BOOL },
124 { "IXANY", 39, TTY_OP_BOOL },
125 { "IXOFF", 40, TTY_OP_BOOL },
126 { "IMAXBEL", 41, TTY_OP_BOOL },
127 { "ISIG", 50, TTY_OP_BOOL },
128 { "ICANON", 51, TTY_OP_BOOL },
129 { "XCASE", 52, TTY_OP_BOOL },
130 { "ECHO", 53, TTY_OP_BOOL },
131 { "ECHOE", 54, TTY_OP_BOOL },
132 { "ECHOK", 55, TTY_OP_BOOL },
133 { "ECHONL", 56, TTY_OP_BOOL },
134 { "NOFLSH", 57, TTY_OP_BOOL },
135 { "TOSTOP", 58, TTY_OP_BOOL },
136 { "IEXTEN", 59, TTY_OP_BOOL },
137 { "ECHOCTL", 60, TTY_OP_BOOL },
138 { "ECHOKE", 61, TTY_OP_BOOL },
139 { "PENDIN", 62, TTY_OP_BOOL }, /* XXX is this a real mode? */
140 { "OPOST", 70, TTY_OP_BOOL },
141 { "OLCUC", 71, TTY_OP_BOOL },
142 { "ONLCR", 72, TTY_OP_BOOL },
143 { "OCRNL", 73, TTY_OP_BOOL },
144 { "ONOCR", 74, TTY_OP_BOOL },
145 { "ONLRET", 75, TTY_OP_BOOL },
146 { "CS7", 90, TTY_OP_BOOL },
147 { "CS8", 91, TTY_OP_BOOL },
148 { "PARENB", 92, TTY_OP_BOOL },
149 { "PARODD", 93, TTY_OP_BOOL }
152 /* Miscellaneous other tty-related constants. */
153 #define SSH_TTY_OP_END 0
154 /* The opcodes for ISPEED/OSPEED differ between SSH-1 and SSH-2. */
155 #define SSH1_TTY_OP_ISPEED 192
156 #define SSH1_TTY_OP_OSPEED 193
157 #define SSH2_TTY_OP_ISPEED 128
158 #define SSH2_TTY_OP_OSPEED 129
160 /* Helper functions for parsing tty-related config. */
161 static unsigned int ssh_tty_parse_specchar(char *s)
166 ret = ctrlparse(s, &next);
167 if (!next) ret = s[0];
169 ret = 255; /* special value meaning "don't set" */
173 static unsigned int ssh_tty_parse_boolean(char *s)
175 if (stricmp(s, "yes") == 0 ||
176 stricmp(s, "on") == 0 ||
177 stricmp(s, "true") == 0 ||
178 stricmp(s, "+") == 0)
180 else if (stricmp(s, "no") == 0 ||
181 stricmp(s, "off") == 0 ||
182 stricmp(s, "false") == 0 ||
183 stricmp(s, "-") == 0)
184 return 0; /* false */
186 return (atoi(s) != 0);
189 #define translate(x) if (type == x) return #x
190 #define translatek(x,ctx) if (type == x && (pkt_kctx == ctx)) return #x
191 #define translatea(x,ctx) if (type == x && (pkt_actx == ctx)) return #x
192 static const char *ssh1_pkt_type(int type)
194 translate(SSH1_MSG_DISCONNECT);
195 translate(SSH1_SMSG_PUBLIC_KEY);
196 translate(SSH1_CMSG_SESSION_KEY);
197 translate(SSH1_CMSG_USER);
198 translate(SSH1_CMSG_AUTH_RSA);
199 translate(SSH1_SMSG_AUTH_RSA_CHALLENGE);
200 translate(SSH1_CMSG_AUTH_RSA_RESPONSE);
201 translate(SSH1_CMSG_AUTH_PASSWORD);
202 translate(SSH1_CMSG_REQUEST_PTY);
203 translate(SSH1_CMSG_WINDOW_SIZE);
204 translate(SSH1_CMSG_EXEC_SHELL);
205 translate(SSH1_CMSG_EXEC_CMD);
206 translate(SSH1_SMSG_SUCCESS);
207 translate(SSH1_SMSG_FAILURE);
208 translate(SSH1_CMSG_STDIN_DATA);
209 translate(SSH1_SMSG_STDOUT_DATA);
210 translate(SSH1_SMSG_STDERR_DATA);
211 translate(SSH1_CMSG_EOF);
212 translate(SSH1_SMSG_EXIT_STATUS);
213 translate(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION);
214 translate(SSH1_MSG_CHANNEL_OPEN_FAILURE);
215 translate(SSH1_MSG_CHANNEL_DATA);
216 translate(SSH1_MSG_CHANNEL_CLOSE);
217 translate(SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION);
218 translate(SSH1_SMSG_X11_OPEN);
219 translate(SSH1_CMSG_PORT_FORWARD_REQUEST);
220 translate(SSH1_MSG_PORT_OPEN);
221 translate(SSH1_CMSG_AGENT_REQUEST_FORWARDING);
222 translate(SSH1_SMSG_AGENT_OPEN);
223 translate(SSH1_MSG_IGNORE);
224 translate(SSH1_CMSG_EXIT_CONFIRMATION);
225 translate(SSH1_CMSG_X11_REQUEST_FORWARDING);
226 translate(SSH1_CMSG_AUTH_RHOSTS_RSA);
227 translate(SSH1_MSG_DEBUG);
228 translate(SSH1_CMSG_REQUEST_COMPRESSION);
229 translate(SSH1_CMSG_AUTH_TIS);
230 translate(SSH1_SMSG_AUTH_TIS_CHALLENGE);
231 translate(SSH1_CMSG_AUTH_TIS_RESPONSE);
232 translate(SSH1_CMSG_AUTH_CCARD);
233 translate(SSH1_SMSG_AUTH_CCARD_CHALLENGE);
234 translate(SSH1_CMSG_AUTH_CCARD_RESPONSE);
237 static const char *ssh2_pkt_type(Pkt_KCtx pkt_kctx, Pkt_ACtx pkt_actx,
240 translatea(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE,SSH2_PKTCTX_GSSAPI);
241 translatea(SSH2_MSG_USERAUTH_GSSAPI_TOKEN,SSH2_PKTCTX_GSSAPI);
242 translatea(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE,SSH2_PKTCTX_GSSAPI);
243 translatea(SSH2_MSG_USERAUTH_GSSAPI_ERROR,SSH2_PKTCTX_GSSAPI);
244 translatea(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK,SSH2_PKTCTX_GSSAPI);
245 translatea(SSH2_MSG_USERAUTH_GSSAPI_MIC, SSH2_PKTCTX_GSSAPI);
246 translate(SSH2_MSG_DISCONNECT);
247 translate(SSH2_MSG_IGNORE);
248 translate(SSH2_MSG_UNIMPLEMENTED);
249 translate(SSH2_MSG_DEBUG);
250 translate(SSH2_MSG_SERVICE_REQUEST);
251 translate(SSH2_MSG_SERVICE_ACCEPT);
252 translate(SSH2_MSG_KEXINIT);
253 translate(SSH2_MSG_NEWKEYS);
254 translatek(SSH2_MSG_KEXDH_INIT, SSH2_PKTCTX_DHGROUP);
255 translatek(SSH2_MSG_KEXDH_REPLY, SSH2_PKTCTX_DHGROUP);
256 translatek(SSH2_MSG_KEX_DH_GEX_REQUEST_OLD, SSH2_PKTCTX_DHGEX);
257 translatek(SSH2_MSG_KEX_DH_GEX_REQUEST, SSH2_PKTCTX_DHGEX);
258 translatek(SSH2_MSG_KEX_DH_GEX_GROUP, SSH2_PKTCTX_DHGEX);
259 translatek(SSH2_MSG_KEX_DH_GEX_INIT, SSH2_PKTCTX_DHGEX);
260 translatek(SSH2_MSG_KEX_DH_GEX_REPLY, SSH2_PKTCTX_DHGEX);
261 translatek(SSH2_MSG_KEXRSA_PUBKEY, SSH2_PKTCTX_RSAKEX);
262 translatek(SSH2_MSG_KEXRSA_SECRET, SSH2_PKTCTX_RSAKEX);
263 translatek(SSH2_MSG_KEXRSA_DONE, SSH2_PKTCTX_RSAKEX);
264 translatek(SSH2_MSG_KEX_ECDH_INIT, SSH2_PKTCTX_ECDHKEX);
265 translatek(SSH2_MSG_KEX_ECDH_REPLY, SSH2_PKTCTX_ECDHKEX);
266 translate(SSH2_MSG_USERAUTH_REQUEST);
267 translate(SSH2_MSG_USERAUTH_FAILURE);
268 translate(SSH2_MSG_USERAUTH_SUCCESS);
269 translate(SSH2_MSG_USERAUTH_BANNER);
270 translatea(SSH2_MSG_USERAUTH_PK_OK, SSH2_PKTCTX_PUBLICKEY);
271 translatea(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, SSH2_PKTCTX_PASSWORD);
272 translatea(SSH2_MSG_USERAUTH_INFO_REQUEST, SSH2_PKTCTX_KBDINTER);
273 translatea(SSH2_MSG_USERAUTH_INFO_RESPONSE, SSH2_PKTCTX_KBDINTER);
274 translate(SSH2_MSG_GLOBAL_REQUEST);
275 translate(SSH2_MSG_REQUEST_SUCCESS);
276 translate(SSH2_MSG_REQUEST_FAILURE);
277 translate(SSH2_MSG_CHANNEL_OPEN);
278 translate(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
279 translate(SSH2_MSG_CHANNEL_OPEN_FAILURE);
280 translate(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
281 translate(SSH2_MSG_CHANNEL_DATA);
282 translate(SSH2_MSG_CHANNEL_EXTENDED_DATA);
283 translate(SSH2_MSG_CHANNEL_EOF);
284 translate(SSH2_MSG_CHANNEL_CLOSE);
285 translate(SSH2_MSG_CHANNEL_REQUEST);
286 translate(SSH2_MSG_CHANNEL_SUCCESS);
287 translate(SSH2_MSG_CHANNEL_FAILURE);
293 /* Enumeration values for fields in SSH-1 packets */
295 PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR, PKT_BIGNUM,
299 * Coroutine mechanics for the sillier bits of the code. If these
300 * macros look impenetrable to you, you might find it helpful to
303 * http://www.chiark.greenend.org.uk/~sgtatham/coroutines.html
305 * which explains the theory behind these macros.
307 * In particular, if you are getting `case expression not constant'
308 * errors when building with MS Visual Studio, this is because MS's
309 * Edit and Continue debugging feature causes their compiler to
310 * violate ANSI C. To disable Edit and Continue debugging:
312 * - right-click ssh.c in the FileView
314 * - select the C/C++ tab and the General category
315 * - under `Debug info:', select anything _other_ than `Program
316 * Database for Edit and Continue'.
318 #define crBegin(v) { int *crLine = &v; switch(v) { case 0:;
319 #define crBeginState crBegin(s->crLine)
320 #define crStateP(t, v) \
322 if (!(v)) { s = (v) = snew(struct t); s->crLine = 0; } \
324 #define crState(t) crStateP(t, ssh->t)
325 #define crFinish(z) } *crLine = 0; return (z); }
326 #define crFinishV } *crLine = 0; return; }
327 #define crFinishFree(z) } sfree(s); return (z); }
328 #define crFinishFreeV } sfree(s); return; }
329 #define crReturn(z) \
331 *crLine =__LINE__; return (z); case __LINE__:;\
335 *crLine=__LINE__; return; case __LINE__:;\
337 #define crStop(z) do{ *crLine = 0; return (z); }while(0)
338 #define crStopV do{ *crLine = 0; return; }while(0)
339 #define crWaitUntil(c) do { crReturn(0); } while (!(c))
340 #define crWaitUntilV(c) do { crReturnV; } while (!(c))
344 static struct Packet *ssh1_pkt_init(int pkt_type);
345 static struct Packet *ssh2_pkt_init(int pkt_type);
346 static void ssh_pkt_ensure(struct Packet *, int length);
347 static void ssh_pkt_adddata(struct Packet *, const void *data, int len);
348 static void ssh_pkt_addbyte(struct Packet *, unsigned char value);
349 static void ssh2_pkt_addbool(struct Packet *, unsigned char value);
350 static void ssh_pkt_adduint32(struct Packet *, unsigned long value);
351 static void ssh_pkt_addstring_start(struct Packet *);
352 static void ssh_pkt_addstring_str(struct Packet *, const char *data);
353 static void ssh_pkt_addstring_data(struct Packet *, const char *data, int len);
354 static void ssh_pkt_addstring(struct Packet *, const char *data);
355 static unsigned char *ssh2_mpint_fmt(Bignum b, int *len);
356 static void ssh1_pkt_addmp(struct Packet *, Bignum b);
357 static void ssh2_pkt_addmp(struct Packet *, Bignum b);
358 static int ssh2_pkt_construct(Ssh, struct Packet *);
359 static void ssh2_pkt_send(Ssh, struct Packet *);
360 static void ssh2_pkt_send_noqueue(Ssh, struct Packet *);
361 static int do_ssh1_login(Ssh ssh, const unsigned char *in, int inlen,
362 struct Packet *pktin);
363 static void do_ssh2_authconn(Ssh ssh, const unsigned char *in, int inlen,
364 struct Packet *pktin);
365 static void ssh2_channel_check_close(struct ssh_channel *c);
366 static void ssh_channel_destroy(struct ssh_channel *c);
367 static void ssh2_msg_something_unimplemented(Ssh ssh, struct Packet *pktin);
370 * Buffer management constants. There are several of these for
371 * various different purposes:
373 * - SSH1_BUFFER_LIMIT is the amount of backlog that must build up
374 * on a local data stream before we throttle the whole SSH
375 * connection (in SSH-1 only). Throttling the whole connection is
376 * pretty drastic so we set this high in the hope it won't
379 * - SSH_MAX_BACKLOG is the amount of backlog that must build up
380 * on the SSH connection itself before we defensively throttle
381 * _all_ local data streams. This is pretty drastic too (though
382 * thankfully unlikely in SSH-2 since the window mechanism should
383 * ensure that the server never has any need to throttle its end
384 * of the connection), so we set this high as well.
386 * - OUR_V2_WINSIZE is the maximum window size we present on SSH-2
389 * - OUR_V2_BIGWIN is the window size we advertise for the only
390 * channel in a simple connection. It must be <= INT_MAX.
392 * - OUR_V2_MAXPKT is the official "maximum packet size" we send
393 * to the remote side. This actually has nothing to do with the
394 * size of the _packet_, but is instead a limit on the amount
395 * of data we're willing to receive in a single SSH2 channel
398 * - OUR_V2_PACKETLIMIT is actually the maximum size of SSH
399 * _packet_ we're prepared to cope with. It must be a multiple
400 * of the cipher block size, and must be at least 35000.
403 #define SSH1_BUFFER_LIMIT 32768
404 #define SSH_MAX_BACKLOG 32768
405 #define OUR_V2_WINSIZE 16384
406 #define OUR_V2_BIGWIN 0x7fffffff
407 #define OUR_V2_MAXPKT 0x4000UL
408 #define OUR_V2_PACKETLIMIT 0x9000UL
410 const static struct ssh_signkey *hostkey_algs[] = {
412 &ssh_ecdsa_nistp256, &ssh_ecdsa_nistp384, &ssh_ecdsa_nistp521,
416 const static struct ssh_mac *macs[] = {
417 &ssh_hmac_sha256, &ssh_hmac_sha1, &ssh_hmac_sha1_96, &ssh_hmac_md5
419 const static struct ssh_mac *buggymacs[] = {
420 &ssh_hmac_sha1_buggy, &ssh_hmac_sha1_96_buggy, &ssh_hmac_md5
423 static void *ssh_comp_none_init(void)
427 static void ssh_comp_none_cleanup(void *handle)
430 static int ssh_comp_none_block(void *handle, unsigned char *block, int len,
431 unsigned char **outblock, int *outlen)
435 static int ssh_comp_none_disable(void *handle)
439 const static struct ssh_compress ssh_comp_none = {
441 ssh_comp_none_init, ssh_comp_none_cleanup, ssh_comp_none_block,
442 ssh_comp_none_init, ssh_comp_none_cleanup, ssh_comp_none_block,
443 ssh_comp_none_disable, NULL
445 extern const struct ssh_compress ssh_zlib;
446 const static struct ssh_compress *compressions[] = {
447 &ssh_zlib, &ssh_comp_none
450 enum { /* channel types */
455 CHAN_SOCKDATA_DORMANT, /* one the remote hasn't confirmed */
457 * CHAN_SHARING indicates a channel which is tracked here on
458 * behalf of a connection-sharing downstream. We do almost nothing
459 * with these channels ourselves: all messages relating to them
460 * get thrown straight to sshshare.c and passed on almost
461 * unmodified to downstream.
465 * CHAN_ZOMBIE is used to indicate a channel for which we've
466 * already destroyed the local data source: for instance, if a
467 * forwarded port experiences a socket error on the local side, we
468 * immediately destroy its local socket and turn the SSH channel
474 typedef void (*handler_fn_t)(Ssh ssh, struct Packet *pktin);
475 typedef void (*chandler_fn_t)(Ssh ssh, struct Packet *pktin, void *ctx);
476 typedef void (*cchandler_fn_t)(struct ssh_channel *, struct Packet *, void *);
479 * Each channel has a queue of outstanding CHANNEL_REQUESTS and their
482 struct outstanding_channel_request {
483 cchandler_fn_t handler;
485 struct outstanding_channel_request *next;
489 * 2-3-4 tree storing channels.
492 Ssh ssh; /* pointer back to main context */
493 unsigned remoteid, localid;
495 /* True if we opened this channel but server hasn't confirmed. */
498 * In SSH-1, this value contains four bits:
500 * 1 We have sent SSH1_MSG_CHANNEL_CLOSE.
501 * 2 We have sent SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION.
502 * 4 We have received SSH1_MSG_CHANNEL_CLOSE.
503 * 8 We have received SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION.
505 * A channel is completely finished with when all four bits are set.
507 * In SSH-2, the four bits mean:
509 * 1 We have sent SSH2_MSG_CHANNEL_EOF.
510 * 2 We have sent SSH2_MSG_CHANNEL_CLOSE.
511 * 4 We have received SSH2_MSG_CHANNEL_EOF.
512 * 8 We have received SSH2_MSG_CHANNEL_CLOSE.
514 * A channel is completely finished with when we have both sent
515 * and received CLOSE.
517 * The symbolic constants below use the SSH-2 terminology, which
518 * is a bit confusing in SSH-1, but we have to use _something_.
520 #define CLOSES_SENT_EOF 1
521 #define CLOSES_SENT_CLOSE 2
522 #define CLOSES_RCVD_EOF 4
523 #define CLOSES_RCVD_CLOSE 8
527 * This flag indicates that an EOF is pending on the outgoing side
528 * of the channel: that is, wherever we're getting the data for
529 * this channel has sent us some data followed by EOF. We can't
530 * actually send the EOF until we've finished sending the data, so
531 * we set this flag instead to remind us to do so once our buffer
537 * True if this channel is causing the underlying connection to be
542 struct ssh2_data_channel {
544 unsigned remwindow, remmaxpkt;
545 /* locwindow is signed so we can cope with excess data. */
546 int locwindow, locmaxwin;
548 * remlocwin is the amount of local window that we think
549 * the remote end had available to it after it sent the
550 * last data packet or window adjust ack.
554 * These store the list of channel requests that haven't
557 struct outstanding_channel_request *chanreq_head, *chanreq_tail;
558 enum { THROTTLED, UNTHROTTLING, UNTHROTTLED } throttle_state;
562 struct ssh_agent_channel {
563 unsigned char *message;
564 unsigned char msglen[4];
565 unsigned lensofar, totallen;
566 int outstanding_requests;
568 struct ssh_x11_channel {
569 struct X11Connection *xconn;
572 struct ssh_pfd_channel {
573 struct PortForwarding *pf;
575 struct ssh_sharing_channel {
582 * 2-3-4 tree storing remote->local port forwardings. SSH-1 and SSH-2
583 * use this structure in different ways, reflecting SSH-2's
584 * altogether saner approach to port forwarding.
586 * In SSH-1, you arrange a remote forwarding by sending the server
587 * the remote port number, and the local destination host:port.
588 * When a connection comes in, the server sends you back that
589 * host:port pair, and you connect to it. This is a ready-made
590 * security hole if you're not on the ball: a malicious server
591 * could send you back _any_ host:port pair, so if you trustingly
592 * connect to the address it gives you then you've just opened the
593 * entire inside of your corporate network just by connecting
594 * through it to a dodgy SSH server. Hence, we must store a list of
595 * host:port pairs we _are_ trying to forward to, and reject a
596 * connection request from the server if it's not in the list.
598 * In SSH-2, each side of the connection minds its own business and
599 * doesn't send unnecessary information to the other. You arrange a
600 * remote forwarding by sending the server just the remote port
601 * number. When a connection comes in, the server tells you which
602 * of its ports was connected to; and _you_ have to remember what
603 * local host:port pair went with that port number.
605 * Hence, in SSH-1 this structure is indexed by destination
606 * host:port pair, whereas in SSH-2 it is indexed by source port.
608 struct ssh_portfwd; /* forward declaration */
610 struct ssh_rportfwd {
611 unsigned sport, dport;
615 struct ssh_portfwd *pfrec;
618 static void free_rportfwd(struct ssh_rportfwd *pf)
621 sfree(pf->sportdesc);
629 * Separately to the rportfwd tree (which is for looking up port
630 * open requests from the server), a tree of _these_ structures is
631 * used to keep track of all the currently open port forwardings,
632 * so that we can reconfigure in mid-session if the user requests
636 enum { DESTROY, KEEP, CREATE } status;
638 unsigned sport, dport;
641 struct ssh_rportfwd *remote;
643 struct PortListener *local;
645 #define free_portfwd(pf) ( \
646 ((pf) ? (sfree((pf)->saddr), sfree((pf)->daddr), \
647 sfree((pf)->sserv), sfree((pf)->dserv)) : (void)0 ), sfree(pf) )
650 long length; /* length of packet: see below */
651 long forcepad; /* SSH-2: force padding to at least this length */
652 int type; /* only used for incoming packets */
653 unsigned long sequence; /* SSH-2 incoming sequence number */
654 unsigned char *data; /* allocated storage */
655 unsigned char *body; /* offset of payload within `data' */
656 long savedpos; /* dual-purpose saved packet position: see below */
657 long maxlen; /* amount of storage allocated for `data' */
658 long encrypted_len; /* for SSH-2 total-size counting */
661 * A note on the 'length' and 'savedpos' fields above.
663 * Incoming packets are set up so that pkt->length is measured
664 * relative to pkt->body, which itself points to a few bytes after
665 * pkt->data (skipping some uninteresting header fields including
666 * the packet type code). The ssh_pkt_get* functions all expect
667 * this setup, and they also use pkt->savedpos to indicate how far
668 * through the packet being decoded they've got - and that, too,
669 * is an offset from pkt->body rather than pkt->data.
671 * During construction of an outgoing packet, however, pkt->length
672 * is measured relative to the base pointer pkt->data, and
673 * pkt->body is not really used for anything until the packet is
674 * ready for sending. In this mode, pkt->savedpos is reused as a
675 * temporary variable by the addstring functions, which write out
676 * a string length field and then keep going back and updating it
677 * as more data is appended to the subsequent string data field;
678 * pkt->savedpos stores the offset (again relative to pkt->data)
679 * of the start of the string data field.
682 /* Extra metadata used in SSH packet logging mode, allowing us to
683 * log in the packet header line that the packet came from a
684 * connection-sharing downstream and what if anything unusual was
685 * done to it. The additional_log_text field is expected to be a
686 * static string - it will not be freed. */
687 unsigned downstream_id;
688 const char *additional_log_text;
691 static void ssh1_protocol(Ssh ssh, const void *vin, int inlen,
692 struct Packet *pktin);
693 static void ssh2_protocol(Ssh ssh, const void *vin, int inlen,
694 struct Packet *pktin);
695 static void ssh2_bare_connection_protocol(Ssh ssh, const void *vin, int inlen,
696 struct Packet *pktin);
697 static void ssh1_protocol_setup(Ssh ssh);
698 static void ssh2_protocol_setup(Ssh ssh);
699 static void ssh2_bare_connection_protocol_setup(Ssh ssh);
700 static void ssh_size(void *handle, int width, int height);
701 static void ssh_special(void *handle, Telnet_Special);
702 static int ssh2_try_send(struct ssh_channel *c);
703 static void ssh2_add_channel_data(struct ssh_channel *c,
704 const char *buf, int len);
705 static void ssh_throttle_all(Ssh ssh, int enable, int bufsize);
706 static void ssh2_set_window(struct ssh_channel *c, int newwin);
707 static int ssh_sendbuffer(void *handle);
708 static int ssh_do_close(Ssh ssh, int notify_exit);
709 static unsigned long ssh_pkt_getuint32(struct Packet *pkt);
710 static int ssh2_pkt_getbool(struct Packet *pkt);
711 static void ssh_pkt_getstring(struct Packet *pkt, char **p, int *length);
712 static void ssh2_timer(void *ctx, unsigned long now);
713 static void do_ssh2_transport(Ssh ssh, const void *vin, int inlen,
714 struct Packet *pktin);
715 static void ssh2_msg_unexpected(Ssh ssh, struct Packet *pktin);
717 struct rdpkt1_state_tag {
718 long len, pad, biglen, to_read;
719 unsigned long realcrc, gotcrc;
723 struct Packet *pktin;
726 struct rdpkt2_state_tag {
727 long len, pad, payload, packetlen, maclen;
730 unsigned long incoming_sequence;
731 struct Packet *pktin;
734 struct rdpkt2_bare_state_tag {
738 unsigned long incoming_sequence;
739 struct Packet *pktin;
742 struct queued_handler;
743 struct queued_handler {
745 chandler_fn_t handler;
747 struct queued_handler *next;
751 const struct plug_function_table *fn;
752 /* the above field _must_ be first in the structure */
762 unsigned char session_key[32];
764 int v1_remote_protoflags;
765 int v1_local_protoflags;
766 int agentfwd_enabled;
769 const struct ssh_cipher *cipher;
772 const struct ssh2_cipher *cscipher, *sccipher;
773 void *cs_cipher_ctx, *sc_cipher_ctx;
774 const struct ssh_mac *csmac, *scmac;
775 int csmac_etm, scmac_etm;
776 void *cs_mac_ctx, *sc_mac_ctx;
777 const struct ssh_compress *cscomp, *sccomp;
778 void *cs_comp_ctx, *sc_comp_ctx;
779 const struct ssh_kex *kex;
780 const struct ssh_signkey *hostkey;
781 char *hostkey_str; /* string representation, for easy checking in rekeys */
782 unsigned char v2_session_id[SSH2_KEX_MAX_HASH_LEN];
783 int v2_session_id_len;
787 int attempting_connshare;
793 int echoing, editing;
797 int ospeed, ispeed; /* temporaries */
798 int term_width, term_height;
800 tree234 *channels; /* indexed by local id */
801 struct ssh_channel *mainchan; /* primary session channel */
802 int ncmode; /* is primary channel direct-tcpip? */
807 tree234 *rportfwds, *portfwds;
811 SSH_STATE_BEFORE_SIZE,
817 int size_needed, eof_needed;
818 int sent_console_eof;
819 int got_pty; /* affects EOF behaviour on main channel */
821 struct Packet **queue;
822 int queuelen, queuesize;
824 unsigned char *deferred_send_data;
825 int deferred_len, deferred_size;
828 * Gross hack: pscp will try to start SFTP but fall back to
829 * scp1 if that fails. This variable is the means by which
830 * scp.c can reach into the SSH code and find out which one it
835 bufchain banner; /* accumulates banners during do_ssh2_authconn */
840 struct X11Display *x11disp;
841 struct X11FakeAuth *x11auth;
842 tree234 *x11authtree;
845 int conn_throttle_count;
848 int v1_stdout_throttling;
849 unsigned long v2_outgoing_sequence;
851 int ssh1_rdpkt_crstate;
852 int ssh2_rdpkt_crstate;
853 int ssh2_bare_rdpkt_crstate;
854 int ssh_gotdata_crstate;
855 int do_ssh1_connection_crstate;
857 void *do_ssh_init_state;
858 void *do_ssh1_login_state;
859 void *do_ssh2_transport_state;
860 void *do_ssh2_authconn_state;
861 void *do_ssh_connection_init_state;
863 struct rdpkt1_state_tag rdpkt1_state;
864 struct rdpkt2_state_tag rdpkt2_state;
865 struct rdpkt2_bare_state_tag rdpkt2_bare_state;
867 /* SSH-1 and SSH-2 use this for different things, but both use it */
868 int protocol_initial_phase_done;
870 void (*protocol) (Ssh ssh, const void *vin, int inlen,
872 struct Packet *(*s_rdpkt) (Ssh ssh, const unsigned char **data,
874 int (*do_ssh_init)(Ssh ssh, unsigned char c);
877 * We maintain our own copy of a Conf structure here. That way,
878 * when we're passed a new one for reconfiguration, we can check
879 * the differences and potentially reconfigure port forwardings
880 * etc in mid-session.
885 * Values cached out of conf so as to avoid the tree234 lookup
886 * cost every time they're used.
891 * Dynamically allocated username string created during SSH
892 * login. Stored in here rather than in the coroutine state so
893 * that it'll be reliably freed if we shut down the SSH session
894 * at some unexpected moment.
899 * Used to transfer data back from async callbacks.
901 void *agent_response;
902 int agent_response_len;
906 * The SSH connection can be set as `frozen', meaning we are
907 * not currently accepting incoming data from the network. This
908 * is slightly more serious than setting the _socket_ as
909 * frozen, because we may already have had data passed to us
910 * from the network which we need to delay processing until
911 * after the freeze is lifted, so we also need a bufchain to
915 bufchain queued_incoming_data;
918 * Dispatch table for packet types that we may have to deal
921 handler_fn_t packet_dispatch[256];
924 * Queues of one-off handler functions for success/failure
925 * indications from a request.
927 struct queued_handler *qhead, *qtail;
928 handler_fn_t q_saved_handler1, q_saved_handler2;
931 * This module deals with sending keepalives.
936 * Track incoming and outgoing data sizes and time, for
939 unsigned long incoming_data_size, outgoing_data_size, deferred_data_size;
940 unsigned long max_data_size;
942 unsigned long next_rekey, last_rekey;
943 const char *deferred_rekey_reason;
946 * Fully qualified host name, which we need if doing GSSAPI.
952 * GSSAPI libraries for this session.
954 struct ssh_gss_liblist *gsslibs;
958 #define logevent(s) logevent(ssh->frontend, s)
960 /* logevent, only printf-formatted. */
961 static void logeventf(Ssh ssh, const char *fmt, ...)
967 buf = dupvprintf(fmt, ap);
973 static void bomb_out(Ssh ssh, char *text)
975 ssh_do_close(ssh, FALSE);
977 connection_fatal(ssh->frontend, "%s", text);
981 #define bombout(msg) bomb_out(ssh, dupprintf msg)
983 /* Helper function for common bits of parsing ttymodes. */
984 static void parse_ttymodes(Ssh ssh,
985 void (*do_mode)(void *data, char *mode, char *val),
990 for (val = conf_get_str_strs(ssh->conf, CONF_ttymodes, NULL, &key);
992 val = conf_get_str_strs(ssh->conf, CONF_ttymodes, key, &key)) {
994 * val[0] is either 'V', indicating that an explicit value
995 * follows it, or 'A' indicating that we should pass the
996 * value through from the local environment via get_ttymode.
999 val = get_ttymode(ssh->frontend, key);
1001 do_mode(data, key, val);
1005 do_mode(data, key, val + 1); /* skip the 'V' */
1009 static int ssh_channelcmp(void *av, void *bv)
1011 struct ssh_channel *a = (struct ssh_channel *) av;
1012 struct ssh_channel *b = (struct ssh_channel *) bv;
1013 if (a->localid < b->localid)
1015 if (a->localid > b->localid)
1019 static int ssh_channelfind(void *av, void *bv)
1021 unsigned *a = (unsigned *) av;
1022 struct ssh_channel *b = (struct ssh_channel *) bv;
1023 if (*a < b->localid)
1025 if (*a > b->localid)
1030 static int ssh_rportcmp_ssh1(void *av, void *bv)
1032 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
1033 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
1035 if ( (i = strcmp(a->dhost, b->dhost)) != 0)
1036 return i < 0 ? -1 : +1;
1037 if (a->dport > b->dport)
1039 if (a->dport < b->dport)
1044 static int ssh_rportcmp_ssh2(void *av, void *bv)
1046 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
1047 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
1049 if ( (i = strcmp(a->shost, b->shost)) != 0)
1050 return i < 0 ? -1 : +1;
1051 if (a->sport > b->sport)
1053 if (a->sport < b->sport)
1059 * Special form of strcmp which can cope with NULL inputs. NULL is
1060 * defined to sort before even the empty string.
1062 static int nullstrcmp(const char *a, const char *b)
1064 if (a == NULL && b == NULL)
1070 return strcmp(a, b);
1073 static int ssh_portcmp(void *av, void *bv)
1075 struct ssh_portfwd *a = (struct ssh_portfwd *) av;
1076 struct ssh_portfwd *b = (struct ssh_portfwd *) bv;
1078 if (a->type > b->type)
1080 if (a->type < b->type)
1082 if (a->addressfamily > b->addressfamily)
1084 if (a->addressfamily < b->addressfamily)
1086 if ( (i = nullstrcmp(a->saddr, b->saddr)) != 0)
1087 return i < 0 ? -1 : +1;
1088 if (a->sport > b->sport)
1090 if (a->sport < b->sport)
1092 if (a->type != 'D') {
1093 if ( (i = nullstrcmp(a->daddr, b->daddr)) != 0)
1094 return i < 0 ? -1 : +1;
1095 if (a->dport > b->dport)
1097 if (a->dport < b->dport)
1103 static int alloc_channel_id(Ssh ssh)
1105 const unsigned CHANNEL_NUMBER_OFFSET = 256;
1106 unsigned low, high, mid;
1108 struct ssh_channel *c;
1111 * First-fit allocation of channel numbers: always pick the
1112 * lowest unused one. To do this, binary-search using the
1113 * counted B-tree to find the largest channel ID which is in a
1114 * contiguous sequence from the beginning. (Precisely
1115 * everything in that sequence must have ID equal to its tree
1116 * index plus CHANNEL_NUMBER_OFFSET.)
1118 tsize = count234(ssh->channels);
1122 while (high - low > 1) {
1123 mid = (high + low) / 2;
1124 c = index234(ssh->channels, mid);
1125 if (c->localid == mid + CHANNEL_NUMBER_OFFSET)
1126 low = mid; /* this one is fine */
1128 high = mid; /* this one is past it */
1131 * Now low points to either -1, or the tree index of the
1132 * largest ID in the initial sequence.
1135 unsigned i = low + 1 + CHANNEL_NUMBER_OFFSET;
1136 assert(NULL == find234(ssh->channels, &i, ssh_channelfind));
1138 return low + 1 + CHANNEL_NUMBER_OFFSET;
1141 static void c_write_stderr(int trusted, const char *buf, int len)
1144 for (i = 0; i < len; i++)
1145 if (buf[i] != '\r' && (trusted || buf[i] == '\n' || (buf[i] & 0x60)))
1146 fputc(buf[i], stderr);
1149 static void c_write(Ssh ssh, const char *buf, int len)
1151 if (flags & FLAG_STDERR)
1152 c_write_stderr(1, buf, len);
1154 from_backend(ssh->frontend, 1, buf, len);
1157 static void c_write_untrusted(Ssh ssh, const char *buf, int len)
1159 if (flags & FLAG_STDERR)
1160 c_write_stderr(0, buf, len);
1162 from_backend_untrusted(ssh->frontend, buf, len);
1165 static void c_write_str(Ssh ssh, const char *buf)
1167 c_write(ssh, buf, strlen(buf));
1170 static void ssh_free_packet(struct Packet *pkt)
1175 static struct Packet *ssh_new_packet(void)
1177 struct Packet *pkt = snew(struct Packet);
1179 pkt->body = pkt->data = NULL;
1185 static void ssh1_log_incoming_packet(Ssh ssh, struct Packet *pkt)
1188 struct logblank_t blanks[4];
1194 if (ssh->logomitdata &&
1195 (pkt->type == SSH1_SMSG_STDOUT_DATA ||
1196 pkt->type == SSH1_SMSG_STDERR_DATA ||
1197 pkt->type == SSH1_MSG_CHANNEL_DATA)) {
1198 /* "Session data" packets - omit the data string. */
1199 if (pkt->type == SSH1_MSG_CHANNEL_DATA)
1200 ssh_pkt_getuint32(pkt); /* skip channel id */
1201 blanks[nblanks].offset = pkt->savedpos + 4;
1202 blanks[nblanks].type = PKTLOG_OMIT;
1203 ssh_pkt_getstring(pkt, &str, &slen);
1205 blanks[nblanks].len = slen;
1209 log_packet(ssh->logctx, PKT_INCOMING, pkt->type,
1210 ssh1_pkt_type(pkt->type),
1211 pkt->body, pkt->length, nblanks, blanks, NULL,
1215 static void ssh1_log_outgoing_packet(Ssh ssh, struct Packet *pkt)
1218 struct logblank_t blanks[4];
1223 * For outgoing packets, pkt->length represents the length of the
1224 * whole packet starting at pkt->data (including some header), and
1225 * pkt->body refers to the point within that where the log-worthy
1226 * payload begins. However, incoming packets expect pkt->length to
1227 * represent only the payload length (that is, it's measured from
1228 * pkt->body not from pkt->data). Temporarily adjust our outgoing
1229 * packet to conform to the incoming-packet semantics, so that we
1230 * can analyse it with the ssh_pkt_get functions.
1232 pkt->length -= (pkt->body - pkt->data);
1235 if (ssh->logomitdata &&
1236 (pkt->type == SSH1_CMSG_STDIN_DATA ||
1237 pkt->type == SSH1_MSG_CHANNEL_DATA)) {
1238 /* "Session data" packets - omit the data string. */
1239 if (pkt->type == SSH1_MSG_CHANNEL_DATA)
1240 ssh_pkt_getuint32(pkt); /* skip channel id */
1241 blanks[nblanks].offset = pkt->savedpos + 4;
1242 blanks[nblanks].type = PKTLOG_OMIT;
1243 ssh_pkt_getstring(pkt, &str, &slen);
1245 blanks[nblanks].len = slen;
1250 if ((pkt->type == SSH1_CMSG_AUTH_PASSWORD ||
1251 pkt->type == SSH1_CMSG_AUTH_TIS_RESPONSE ||
1252 pkt->type == SSH1_CMSG_AUTH_CCARD_RESPONSE) &&
1253 conf_get_int(ssh->conf, CONF_logomitpass)) {
1254 /* If this is a password or similar packet, blank the password(s). */
1255 blanks[nblanks].offset = 0;
1256 blanks[nblanks].len = pkt->length;
1257 blanks[nblanks].type = PKTLOG_BLANK;
1259 } else if (pkt->type == SSH1_CMSG_X11_REQUEST_FORWARDING &&
1260 conf_get_int(ssh->conf, CONF_logomitpass)) {
1262 * If this is an X forwarding request packet, blank the fake
1265 * Note that while we blank the X authentication data here, we
1266 * don't take any special action to blank the start of an X11
1267 * channel, so using MIT-MAGIC-COOKIE-1 and actually opening
1268 * an X connection without having session blanking enabled is
1269 * likely to leak your cookie into the log.
1272 ssh_pkt_getstring(pkt, &str, &slen);
1273 blanks[nblanks].offset = pkt->savedpos;
1274 blanks[nblanks].type = PKTLOG_BLANK;
1275 ssh_pkt_getstring(pkt, &str, &slen);
1277 blanks[nblanks].len = pkt->savedpos - blanks[nblanks].offset;
1282 log_packet(ssh->logctx, PKT_OUTGOING, pkt->data[12],
1283 ssh1_pkt_type(pkt->data[12]),
1284 pkt->body, pkt->length,
1285 nblanks, blanks, NULL, 0, NULL);
1288 * Undo the above adjustment of pkt->length, to put the packet
1289 * back in the state we found it.
1291 pkt->length += (pkt->body - pkt->data);
1295 * Collect incoming data in the incoming packet buffer.
1296 * Decipher and verify the packet when it is completely read.
1297 * Drop SSH1_MSG_DEBUG and SSH1_MSG_IGNORE packets.
1298 * Update the *data and *datalen variables.
1299 * Return a Packet structure when a packet is completed.
1301 static struct Packet *ssh1_rdpkt(Ssh ssh, const unsigned char **data,
1304 struct rdpkt1_state_tag *st = &ssh->rdpkt1_state;
1306 crBegin(ssh->ssh1_rdpkt_crstate);
1308 st->pktin = ssh_new_packet();
1310 st->pktin->type = 0;
1311 st->pktin->length = 0;
1313 for (st->i = st->len = 0; st->i < 4; st->i++) {
1314 while ((*datalen) == 0)
1316 st->len = (st->len << 8) + **data;
1317 (*data)++, (*datalen)--;
1320 st->pad = 8 - (st->len % 8);
1321 st->biglen = st->len + st->pad;
1322 st->pktin->length = st->len - 5;
1324 if (st->biglen < 0) {
1325 bombout(("Extremely large packet length from server suggests"
1326 " data stream corruption"));
1327 ssh_free_packet(st->pktin);
1331 st->pktin->maxlen = st->biglen;
1332 st->pktin->data = snewn(st->biglen + APIEXTRA, unsigned char);
1334 st->to_read = st->biglen;
1335 st->p = st->pktin->data;
1336 while (st->to_read > 0) {
1337 st->chunk = st->to_read;
1338 while ((*datalen) == 0)
1340 if (st->chunk > (*datalen))
1341 st->chunk = (*datalen);
1342 memcpy(st->p, *data, st->chunk);
1344 *datalen -= st->chunk;
1346 st->to_read -= st->chunk;
1349 if (ssh->cipher && detect_attack(ssh->crcda_ctx, st->pktin->data,
1350 st->biglen, NULL)) {
1351 bombout(("Network attack (CRC compensation) detected!"));
1352 ssh_free_packet(st->pktin);
1357 ssh->cipher->decrypt(ssh->v1_cipher_ctx, st->pktin->data, st->biglen);
1359 st->realcrc = crc32_compute(st->pktin->data, st->biglen - 4);
1360 st->gotcrc = GET_32BIT(st->pktin->data + st->biglen - 4);
1361 if (st->gotcrc != st->realcrc) {
1362 bombout(("Incorrect CRC received on packet"));
1363 ssh_free_packet(st->pktin);
1367 st->pktin->body = st->pktin->data + st->pad + 1;
1369 if (ssh->v1_compressing) {
1370 unsigned char *decompblk;
1372 if (!zlib_decompress_block(ssh->sc_comp_ctx,
1373 st->pktin->body - 1, st->pktin->length + 1,
1374 &decompblk, &decomplen)) {
1375 bombout(("Zlib decompression encountered invalid data"));
1376 ssh_free_packet(st->pktin);
1380 if (st->pktin->maxlen < st->pad + decomplen) {
1381 st->pktin->maxlen = st->pad + decomplen;
1382 st->pktin->data = sresize(st->pktin->data,
1383 st->pktin->maxlen + APIEXTRA,
1385 st->pktin->body = st->pktin->data + st->pad + 1;
1388 memcpy(st->pktin->body - 1, decompblk, decomplen);
1390 st->pktin->length = decomplen - 1;
1393 st->pktin->type = st->pktin->body[-1];
1396 * Now pktin->body and pktin->length identify the semantic content
1397 * of the packet, excluding the initial type byte.
1401 ssh1_log_incoming_packet(ssh, st->pktin);
1403 st->pktin->savedpos = 0;
1405 crFinish(st->pktin);
1408 static void ssh2_log_incoming_packet(Ssh ssh, struct Packet *pkt)
1411 struct logblank_t blanks[4];
1417 if (ssh->logomitdata &&
1418 (pkt->type == SSH2_MSG_CHANNEL_DATA ||
1419 pkt->type == SSH2_MSG_CHANNEL_EXTENDED_DATA)) {
1420 /* "Session data" packets - omit the data string. */
1421 ssh_pkt_getuint32(pkt); /* skip channel id */
1422 if (pkt->type == SSH2_MSG_CHANNEL_EXTENDED_DATA)
1423 ssh_pkt_getuint32(pkt); /* skip extended data type */
1424 blanks[nblanks].offset = pkt->savedpos + 4;
1425 blanks[nblanks].type = PKTLOG_OMIT;
1426 ssh_pkt_getstring(pkt, &str, &slen);
1428 blanks[nblanks].len = slen;
1433 log_packet(ssh->logctx, PKT_INCOMING, pkt->type,
1434 ssh2_pkt_type(ssh->pkt_kctx, ssh->pkt_actx, pkt->type),
1435 pkt->body, pkt->length, nblanks, blanks, &pkt->sequence,
1439 static void ssh2_log_outgoing_packet(Ssh ssh, struct Packet *pkt)
1442 struct logblank_t blanks[4];
1447 * For outgoing packets, pkt->length represents the length of the
1448 * whole packet starting at pkt->data (including some header), and
1449 * pkt->body refers to the point within that where the log-worthy
1450 * payload begins. However, incoming packets expect pkt->length to
1451 * represent only the payload length (that is, it's measured from
1452 * pkt->body not from pkt->data). Temporarily adjust our outgoing
1453 * packet to conform to the incoming-packet semantics, so that we
1454 * can analyse it with the ssh_pkt_get functions.
1456 pkt->length -= (pkt->body - pkt->data);
1459 if (ssh->logomitdata &&
1460 (pkt->type == SSH2_MSG_CHANNEL_DATA ||
1461 pkt->type == SSH2_MSG_CHANNEL_EXTENDED_DATA)) {
1462 /* "Session data" packets - omit the data string. */
1463 ssh_pkt_getuint32(pkt); /* skip channel id */
1464 if (pkt->type == SSH2_MSG_CHANNEL_EXTENDED_DATA)
1465 ssh_pkt_getuint32(pkt); /* skip extended data type */
1466 blanks[nblanks].offset = pkt->savedpos + 4;
1467 blanks[nblanks].type = PKTLOG_OMIT;
1468 ssh_pkt_getstring(pkt, &str, &slen);
1470 blanks[nblanks].len = slen;
1475 if (pkt->type == SSH2_MSG_USERAUTH_REQUEST &&
1476 conf_get_int(ssh->conf, CONF_logomitpass)) {
1477 /* If this is a password packet, blank the password(s). */
1479 ssh_pkt_getstring(pkt, &str, &slen);
1480 ssh_pkt_getstring(pkt, &str, &slen);
1481 ssh_pkt_getstring(pkt, &str, &slen);
1482 if (slen == 8 && !memcmp(str, "password", 8)) {
1483 ssh2_pkt_getbool(pkt);
1484 /* Blank the password field. */
1485 blanks[nblanks].offset = pkt->savedpos;
1486 blanks[nblanks].type = PKTLOG_BLANK;
1487 ssh_pkt_getstring(pkt, &str, &slen);
1489 blanks[nblanks].len = pkt->savedpos - blanks[nblanks].offset;
1491 /* If there's another password field beyond it (change of
1492 * password), blank that too. */
1493 ssh_pkt_getstring(pkt, &str, &slen);
1495 blanks[nblanks-1].len =
1496 pkt->savedpos - blanks[nblanks].offset;
1499 } else if (ssh->pkt_actx == SSH2_PKTCTX_KBDINTER &&
1500 pkt->type == SSH2_MSG_USERAUTH_INFO_RESPONSE &&
1501 conf_get_int(ssh->conf, CONF_logomitpass)) {
1502 /* If this is a keyboard-interactive response packet, blank
1505 ssh_pkt_getuint32(pkt);
1506 blanks[nblanks].offset = pkt->savedpos;
1507 blanks[nblanks].type = PKTLOG_BLANK;
1509 ssh_pkt_getstring(pkt, &str, &slen);
1513 blanks[nblanks].len = pkt->savedpos - blanks[nblanks].offset;
1515 } else if (pkt->type == SSH2_MSG_CHANNEL_REQUEST &&
1516 conf_get_int(ssh->conf, CONF_logomitpass)) {
1518 * If this is an X forwarding request packet, blank the fake
1521 * Note that while we blank the X authentication data here, we
1522 * don't take any special action to blank the start of an X11
1523 * channel, so using MIT-MAGIC-COOKIE-1 and actually opening
1524 * an X connection without having session blanking enabled is
1525 * likely to leak your cookie into the log.
1528 ssh_pkt_getuint32(pkt);
1529 ssh_pkt_getstring(pkt, &str, &slen);
1530 if (slen == 7 && !memcmp(str, "x11-req", 0)) {
1531 ssh2_pkt_getbool(pkt);
1532 ssh2_pkt_getbool(pkt);
1533 ssh_pkt_getstring(pkt, &str, &slen);
1534 blanks[nblanks].offset = pkt->savedpos;
1535 blanks[nblanks].type = PKTLOG_BLANK;
1536 ssh_pkt_getstring(pkt, &str, &slen);
1538 blanks[nblanks].len = pkt->savedpos - blanks[nblanks].offset;
1544 log_packet(ssh->logctx, PKT_OUTGOING, pkt->data[5],
1545 ssh2_pkt_type(ssh->pkt_kctx, ssh->pkt_actx, pkt->data[5]),
1546 pkt->body, pkt->length, nblanks, blanks,
1547 &ssh->v2_outgoing_sequence,
1548 pkt->downstream_id, pkt->additional_log_text);
1551 * Undo the above adjustment of pkt->length, to put the packet
1552 * back in the state we found it.
1554 pkt->length += (pkt->body - pkt->data);
1557 static struct Packet *ssh2_rdpkt(Ssh ssh, const unsigned char **data,
1560 struct rdpkt2_state_tag *st = &ssh->rdpkt2_state;
1562 crBegin(ssh->ssh2_rdpkt_crstate);
1564 st->pktin = ssh_new_packet();
1566 st->pktin->type = 0;
1567 st->pktin->length = 0;
1569 st->cipherblk = ssh->sccipher->blksize;
1572 if (st->cipherblk < 8)
1574 st->maclen = ssh->scmac ? ssh->scmac->len : 0;
1576 if (ssh->sccipher && (ssh->sccipher->flags & SSH_CIPHER_IS_CBC) &&
1577 ssh->scmac && !ssh->scmac_etm) {
1579 * When dealing with a CBC-mode cipher, we want to avoid the
1580 * possibility of an attacker's tweaking the ciphertext stream
1581 * so as to cause us to feed the same block to the block
1582 * cipher more than once and thus leak information
1583 * (VU#958563). The way we do this is not to take any
1584 * decisions on the basis of anything we've decrypted until
1585 * we've verified it with a MAC. That includes the packet
1586 * length, so we just read data and check the MAC repeatedly,
1587 * and when the MAC passes, see if the length we've got is
1590 * This defence is unnecessary in OpenSSH ETM mode, because
1591 * the whole point of ETM mode is that the attacker can't
1592 * tweak the ciphertext stream at all without the MAC
1593 * detecting it before we decrypt anything.
1596 /* May as well allocate the whole lot now. */
1597 st->pktin->data = snewn(OUR_V2_PACKETLIMIT + st->maclen + APIEXTRA,
1600 /* Read an amount corresponding to the MAC. */
1601 for (st->i = 0; st->i < st->maclen; st->i++) {
1602 while ((*datalen) == 0)
1604 st->pktin->data[st->i] = *(*data)++;
1610 unsigned char seq[4];
1611 ssh->scmac->start(ssh->sc_mac_ctx);
1612 PUT_32BIT(seq, st->incoming_sequence);
1613 ssh->scmac->bytes(ssh->sc_mac_ctx, seq, 4);
1616 for (;;) { /* Once around this loop per cipher block. */
1617 /* Read another cipher-block's worth, and tack it onto the end. */
1618 for (st->i = 0; st->i < st->cipherblk; st->i++) {
1619 while ((*datalen) == 0)
1621 st->pktin->data[st->packetlen+st->maclen+st->i] = *(*data)++;
1624 /* Decrypt one more block (a little further back in the stream). */
1625 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
1626 st->pktin->data + st->packetlen,
1628 /* Feed that block to the MAC. */
1629 ssh->scmac->bytes(ssh->sc_mac_ctx,
1630 st->pktin->data + st->packetlen, st->cipherblk);
1631 st->packetlen += st->cipherblk;
1632 /* See if that gives us a valid packet. */
1633 if (ssh->scmac->verresult(ssh->sc_mac_ctx,
1634 st->pktin->data + st->packetlen) &&
1635 ((st->len = toint(GET_32BIT(st->pktin->data))) ==
1638 if (st->packetlen >= OUR_V2_PACKETLIMIT) {
1639 bombout(("No valid incoming packet found"));
1640 ssh_free_packet(st->pktin);
1644 st->pktin->maxlen = st->packetlen + st->maclen;
1645 st->pktin->data = sresize(st->pktin->data,
1646 st->pktin->maxlen + APIEXTRA,
1648 } else if (ssh->scmac && ssh->scmac_etm) {
1649 st->pktin->data = snewn(4 + APIEXTRA, unsigned char);
1652 * OpenSSH encrypt-then-MAC mode: the packet length is
1653 * unencrypted, unless the cipher supports length encryption.
1655 for (st->i = st->len = 0; st->i < 4; st->i++) {
1656 while ((*datalen) == 0)
1658 st->pktin->data[st->i] = *(*data)++;
1661 /* Cipher supports length decryption, so do it */
1662 if (ssh->sccipher && (ssh->sccipher->flags & SSH_CIPHER_SEPARATE_LENGTH)) {
1663 /* Keep the packet the same though, so the MAC passes */
1664 unsigned char len[4];
1665 memcpy(len, st->pktin->data, 4);
1666 ssh->sccipher->decrypt_length(ssh->sc_cipher_ctx, len, 4, st->incoming_sequence);
1667 st->len = toint(GET_32BIT(len));
1669 st->len = toint(GET_32BIT(st->pktin->data));
1673 * _Completely_ silly lengths should be stomped on before they
1674 * do us any more damage.
1676 if (st->len < 0 || st->len > OUR_V2_PACKETLIMIT ||
1677 st->len % st->cipherblk != 0) {
1678 bombout(("Incoming packet length field was garbled"));
1679 ssh_free_packet(st->pktin);
1684 * So now we can work out the total packet length.
1686 st->packetlen = st->len + 4;
1689 * Allocate memory for the rest of the packet.
1691 st->pktin->maxlen = st->packetlen + st->maclen;
1692 st->pktin->data = sresize(st->pktin->data,
1693 st->pktin->maxlen + APIEXTRA,
1697 * Read the remainder of the packet.
1699 for (st->i = 4; st->i < st->packetlen + st->maclen; st->i++) {
1700 while ((*datalen) == 0)
1702 st->pktin->data[st->i] = *(*data)++;
1710 && !ssh->scmac->verify(ssh->sc_mac_ctx, st->pktin->data,
1711 st->len + 4, st->incoming_sequence)) {
1712 bombout(("Incorrect MAC received on packet"));
1713 ssh_free_packet(st->pktin);
1717 /* Decrypt everything between the length field and the MAC. */
1719 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
1720 st->pktin->data + 4,
1723 st->pktin->data = snewn(st->cipherblk + APIEXTRA, unsigned char);
1726 * Acquire and decrypt the first block of the packet. This will
1727 * contain the length and padding details.
1729 for (st->i = st->len = 0; st->i < st->cipherblk; st->i++) {
1730 while ((*datalen) == 0)
1732 st->pktin->data[st->i] = *(*data)++;
1737 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
1738 st->pktin->data, st->cipherblk);
1741 * Now get the length figure.
1743 st->len = toint(GET_32BIT(st->pktin->data));
1746 * _Completely_ silly lengths should be stomped on before they
1747 * do us any more damage.
1749 if (st->len < 0 || st->len > OUR_V2_PACKETLIMIT ||
1750 (st->len + 4) % st->cipherblk != 0) {
1751 bombout(("Incoming packet was garbled on decryption"));
1752 ssh_free_packet(st->pktin);
1757 * So now we can work out the total packet length.
1759 st->packetlen = st->len + 4;
1762 * Allocate memory for the rest of the packet.
1764 st->pktin->maxlen = st->packetlen + st->maclen;
1765 st->pktin->data = sresize(st->pktin->data,
1766 st->pktin->maxlen + APIEXTRA,
1770 * Read and decrypt the remainder of the packet.
1772 for (st->i = st->cipherblk; st->i < st->packetlen + st->maclen;
1774 while ((*datalen) == 0)
1776 st->pktin->data[st->i] = *(*data)++;
1779 /* Decrypt everything _except_ the MAC. */
1781 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
1782 st->pktin->data + st->cipherblk,
1783 st->packetlen - st->cipherblk);
1789 && !ssh->scmac->verify(ssh->sc_mac_ctx, st->pktin->data,
1790 st->len + 4, st->incoming_sequence)) {
1791 bombout(("Incorrect MAC received on packet"));
1792 ssh_free_packet(st->pktin);
1796 /* Get and sanity-check the amount of random padding. */
1797 st->pad = st->pktin->data[4];
1798 if (st->pad < 4 || st->len - st->pad < 1) {
1799 bombout(("Invalid padding length on received packet"));
1800 ssh_free_packet(st->pktin);
1804 * This enables us to deduce the payload length.
1806 st->payload = st->len - st->pad - 1;
1808 st->pktin->length = st->payload + 5;
1809 st->pktin->encrypted_len = st->packetlen;
1811 st->pktin->sequence = st->incoming_sequence++;
1813 st->pktin->length = st->packetlen - st->pad;
1814 assert(st->pktin->length >= 0);
1817 * Decompress packet payload.
1820 unsigned char *newpayload;
1823 ssh->sccomp->decompress(ssh->sc_comp_ctx,
1824 st->pktin->data + 5, st->pktin->length - 5,
1825 &newpayload, &newlen)) {
1826 if (st->pktin->maxlen < newlen + 5) {
1827 st->pktin->maxlen = newlen + 5;
1828 st->pktin->data = sresize(st->pktin->data,
1829 st->pktin->maxlen + APIEXTRA,
1832 st->pktin->length = 5 + newlen;
1833 memcpy(st->pktin->data + 5, newpayload, newlen);
1839 * RFC 4253 doesn't explicitly say that completely empty packets
1840 * with no type byte are forbidden, so treat them as deserving
1841 * an SSH_MSG_UNIMPLEMENTED.
1843 if (st->pktin->length <= 5) { /* == 5 we hope, but robustness */
1844 ssh2_msg_something_unimplemented(ssh, st->pktin);
1848 * pktin->body and pktin->length should identify the semantic
1849 * content of the packet, excluding the initial type byte.
1851 st->pktin->type = st->pktin->data[5];
1852 st->pktin->body = st->pktin->data + 6;
1853 st->pktin->length -= 6;
1854 assert(st->pktin->length >= 0); /* one last double-check */
1857 ssh2_log_incoming_packet(ssh, st->pktin);
1859 st->pktin->savedpos = 0;
1861 crFinish(st->pktin);
1864 static struct Packet *ssh2_bare_connection_rdpkt(Ssh ssh,
1865 const unsigned char **data,
1868 struct rdpkt2_bare_state_tag *st = &ssh->rdpkt2_bare_state;
1870 crBegin(ssh->ssh2_bare_rdpkt_crstate);
1873 * Read the packet length field.
1875 for (st->i = 0; st->i < 4; st->i++) {
1876 while ((*datalen) == 0)
1878 st->length[st->i] = *(*data)++;
1882 st->packetlen = toint(GET_32BIT_MSB_FIRST(st->length));
1883 if (st->packetlen <= 0 || st->packetlen >= OUR_V2_PACKETLIMIT) {
1884 bombout(("Invalid packet length received"));
1888 st->pktin = ssh_new_packet();
1889 st->pktin->data = snewn(st->packetlen, unsigned char);
1891 st->pktin->encrypted_len = st->packetlen;
1893 st->pktin->sequence = st->incoming_sequence++;
1896 * Read the remainder of the packet.
1898 for (st->i = 0; st->i < st->packetlen; st->i++) {
1899 while ((*datalen) == 0)
1901 st->pktin->data[st->i] = *(*data)++;
1906 * pktin->body and pktin->length should identify the semantic
1907 * content of the packet, excluding the initial type byte.
1909 st->pktin->type = st->pktin->data[0];
1910 st->pktin->body = st->pktin->data + 1;
1911 st->pktin->length = st->packetlen - 1;
1914 * Log incoming packet, possibly omitting sensitive fields.
1917 ssh2_log_incoming_packet(ssh, st->pktin);
1919 st->pktin->savedpos = 0;
1921 crFinish(st->pktin);
1924 static int s_wrpkt_prepare(Ssh ssh, struct Packet *pkt, int *offset_p)
1926 int pad, biglen, i, pktoffs;
1930 * XXX various versions of SC (including 8.8.4) screw up the
1931 * register allocation in this function and use the same register
1932 * (D6) for len and as a temporary, with predictable results. The
1933 * following sledgehammer prevents this.
1940 ssh1_log_outgoing_packet(ssh, pkt);
1942 if (ssh->v1_compressing) {
1943 unsigned char *compblk;
1945 zlib_compress_block(ssh->cs_comp_ctx,
1946 pkt->data + 12, pkt->length - 12,
1947 &compblk, &complen);
1948 ssh_pkt_ensure(pkt, complen + 2); /* just in case it's got bigger */
1949 memcpy(pkt->data + 12, compblk, complen);
1951 pkt->length = complen + 12;
1954 ssh_pkt_ensure(pkt, pkt->length + 4); /* space for CRC */
1956 len = pkt->length - 4 - 8; /* len(type+data+CRC) */
1957 pad = 8 - (len % 8);
1959 biglen = len + pad; /* len(padding+type+data+CRC) */
1961 for (i = pktoffs; i < 4+8; i++)
1962 pkt->data[i] = random_byte();
1963 crc = crc32_compute(pkt->data + pktoffs + 4, biglen - 4); /* all ex len */
1964 PUT_32BIT(pkt->data + pktoffs + 4 + biglen - 4, crc);
1965 PUT_32BIT(pkt->data + pktoffs, len);
1968 ssh->cipher->encrypt(ssh->v1_cipher_ctx,
1969 pkt->data + pktoffs + 4, biglen);
1971 if (offset_p) *offset_p = pktoffs;
1972 return biglen + 4; /* len(length+padding+type+data+CRC) */
1975 static int s_write(Ssh ssh, void *data, int len)
1978 log_packet(ssh->logctx, PKT_OUTGOING, -1, NULL, data, len,
1979 0, NULL, NULL, 0, NULL);
1982 return sk_write(ssh->s, (char *)data, len);
1985 static void s_wrpkt(Ssh ssh, struct Packet *pkt)
1987 int len, backlog, offset;
1988 len = s_wrpkt_prepare(ssh, pkt, &offset);
1989 backlog = s_write(ssh, pkt->data + offset, len);
1990 if (backlog > SSH_MAX_BACKLOG)
1991 ssh_throttle_all(ssh, 1, backlog);
1992 ssh_free_packet(pkt);
1995 static void s_wrpkt_defer(Ssh ssh, struct Packet *pkt)
1998 len = s_wrpkt_prepare(ssh, pkt, &offset);
1999 if (ssh->deferred_len + len > ssh->deferred_size) {
2000 ssh->deferred_size = ssh->deferred_len + len + 128;
2001 ssh->deferred_send_data = sresize(ssh->deferred_send_data,
2005 memcpy(ssh->deferred_send_data + ssh->deferred_len,
2006 pkt->data + offset, len);
2007 ssh->deferred_len += len;
2008 ssh_free_packet(pkt);
2012 * Construct a SSH-1 packet with the specified contents.
2013 * (This all-at-once interface used to be the only one, but now SSH-1
2014 * packets can also be constructed incrementally.)
2016 static struct Packet *construct_packet(Ssh ssh, int pkttype, va_list ap)
2022 pkt = ssh1_pkt_init(pkttype);
2024 while ((argtype = va_arg(ap, int)) != PKT_END) {
2025 unsigned char *argp, argchar;
2027 unsigned long argint;
2030 /* Actual fields in the packet */
2032 argint = va_arg(ap, int);
2033 ssh_pkt_adduint32(pkt, argint);
2036 argchar = (unsigned char) va_arg(ap, int);
2037 ssh_pkt_addbyte(pkt, argchar);
2040 argp = va_arg(ap, unsigned char *);
2041 arglen = va_arg(ap, int);
2042 ssh_pkt_adddata(pkt, argp, arglen);
2045 sargp = va_arg(ap, char *);
2046 ssh_pkt_addstring(pkt, sargp);
2049 bn = va_arg(ap, Bignum);
2050 ssh1_pkt_addmp(pkt, bn);
2058 static void send_packet(Ssh ssh, int pkttype, ...)
2062 va_start(ap, pkttype);
2063 pkt = construct_packet(ssh, pkttype, ap);
2068 static void defer_packet(Ssh ssh, int pkttype, ...)
2072 va_start(ap, pkttype);
2073 pkt = construct_packet(ssh, pkttype, ap);
2075 s_wrpkt_defer(ssh, pkt);
2078 static int ssh_versioncmp(const char *a, const char *b)
2081 unsigned long av, bv;
2083 av = strtoul(a, &ae, 10);
2084 bv = strtoul(b, &be, 10);
2086 return (av < bv ? -1 : +1);
2091 av = strtoul(ae, &ae, 10);
2092 bv = strtoul(be, &be, 10);
2094 return (av < bv ? -1 : +1);
2099 * Utility routines for putting an SSH-protocol `string' and
2100 * `uint32' into a hash state.
2102 static void hash_string(const struct ssh_hash *h, void *s, void *str, int len)
2104 unsigned char lenblk[4];
2105 PUT_32BIT(lenblk, len);
2106 h->bytes(s, lenblk, 4);
2107 h->bytes(s, str, len);
2110 static void hash_uint32(const struct ssh_hash *h, void *s, unsigned i)
2112 unsigned char intblk[4];
2113 PUT_32BIT(intblk, i);
2114 h->bytes(s, intblk, 4);
2118 * Packet construction functions. Mostly shared between SSH-1 and SSH-2.
2120 static void ssh_pkt_ensure(struct Packet *pkt, int length)
2122 if (pkt->maxlen < length) {
2123 unsigned char *body = pkt->body;
2124 int offset = body ? body - pkt->data : 0;
2125 pkt->maxlen = length + 256;
2126 pkt->data = sresize(pkt->data, pkt->maxlen + APIEXTRA, unsigned char);
2127 if (body) pkt->body = pkt->data + offset;
2130 static void ssh_pkt_adddata(struct Packet *pkt, const void *data, int len)
2133 ssh_pkt_ensure(pkt, pkt->length);
2134 memcpy(pkt->data + pkt->length - len, data, len);
2136 static void ssh_pkt_addbyte(struct Packet *pkt, unsigned char byte)
2138 ssh_pkt_adddata(pkt, &byte, 1);
2140 static void ssh2_pkt_addbool(struct Packet *pkt, unsigned char value)
2142 ssh_pkt_adddata(pkt, &value, 1);
2144 static void ssh_pkt_adduint32(struct Packet *pkt, unsigned long value)
2147 PUT_32BIT(x, value);
2148 ssh_pkt_adddata(pkt, x, 4);
2150 static void ssh_pkt_addstring_start(struct Packet *pkt)
2152 ssh_pkt_adduint32(pkt, 0);
2153 pkt->savedpos = pkt->length;
2155 static void ssh_pkt_addstring_data(struct Packet *pkt, const char *data,
2158 ssh_pkt_adddata(pkt, data, len);
2159 PUT_32BIT(pkt->data + pkt->savedpos - 4, pkt->length - pkt->savedpos);
2161 static void ssh_pkt_addstring_str(struct Packet *pkt, const char *data)
2163 ssh_pkt_addstring_data(pkt, data, strlen(data));
2165 static void ssh_pkt_addstring(struct Packet *pkt, const char *data)
2167 ssh_pkt_addstring_start(pkt);
2168 ssh_pkt_addstring_str(pkt, data);
2170 static void ssh1_pkt_addmp(struct Packet *pkt, Bignum b)
2172 int len = ssh1_bignum_length(b);
2173 unsigned char *data = snewn(len, unsigned char);
2174 (void) ssh1_write_bignum(data, b);
2175 ssh_pkt_adddata(pkt, data, len);
2178 static unsigned char *ssh2_mpint_fmt(Bignum b, int *len)
2181 int i, n = (bignum_bitcount(b) + 7) / 8;
2182 p = snewn(n + 1, unsigned char);
2184 for (i = 1; i <= n; i++)
2185 p[i] = bignum_byte(b, n - i);
2187 while (i <= n && p[i] == 0 && (p[i + 1] & 0x80) == 0)
2189 memmove(p, p + i, n + 1 - i);
2193 static void ssh2_pkt_addmp(struct Packet *pkt, Bignum b)
2197 p = ssh2_mpint_fmt(b, &len);
2198 ssh_pkt_addstring_start(pkt);
2199 ssh_pkt_addstring_data(pkt, (char *)p, len);
2203 static struct Packet *ssh1_pkt_init(int pkt_type)
2205 struct Packet *pkt = ssh_new_packet();
2206 pkt->length = 4 + 8; /* space for length + max padding */
2207 ssh_pkt_addbyte(pkt, pkt_type);
2208 pkt->body = pkt->data + pkt->length;
2209 pkt->type = pkt_type;
2210 pkt->downstream_id = 0;
2211 pkt->additional_log_text = NULL;
2215 /* For legacy code (SSH-1 and -2 packet construction used to be separate) */
2216 #define ssh2_pkt_ensure(pkt, length) ssh_pkt_ensure(pkt, length)
2217 #define ssh2_pkt_adddata(pkt, data, len) ssh_pkt_adddata(pkt, data, len)
2218 #define ssh2_pkt_addbyte(pkt, byte) ssh_pkt_addbyte(pkt, byte)
2219 #define ssh2_pkt_adduint32(pkt, value) ssh_pkt_adduint32(pkt, value)
2220 #define ssh2_pkt_addstring_start(pkt) ssh_pkt_addstring_start(pkt)
2221 #define ssh2_pkt_addstring_str(pkt, data) ssh_pkt_addstring_str(pkt, data)
2222 #define ssh2_pkt_addstring_data(pkt, data, len) ssh_pkt_addstring_data(pkt, data, len)
2223 #define ssh2_pkt_addstring(pkt, data) ssh_pkt_addstring(pkt, data)
2225 static struct Packet *ssh2_pkt_init(int pkt_type)
2227 struct Packet *pkt = ssh_new_packet();
2228 pkt->length = 5; /* space for packet length + padding length */
2230 pkt->type = pkt_type;
2231 ssh_pkt_addbyte(pkt, (unsigned char) pkt_type);
2232 pkt->body = pkt->data + pkt->length; /* after packet type */
2233 pkt->downstream_id = 0;
2234 pkt->additional_log_text = NULL;
2239 * Construct an SSH-2 final-form packet: compress it, encrypt it,
2240 * put the MAC on it. Final packet, ready to be sent, is stored in
2241 * pkt->data. Total length is returned.
2243 static int ssh2_pkt_construct(Ssh ssh, struct Packet *pkt)
2245 int cipherblk, maclen, padding, unencrypted_prefix, i;
2248 ssh2_log_outgoing_packet(ssh, pkt);
2250 if (ssh->bare_connection) {
2252 * Trivial packet construction for the bare connection
2255 PUT_32BIT(pkt->data + 1, pkt->length - 5);
2256 pkt->body = pkt->data + 1;
2257 ssh->v2_outgoing_sequence++; /* only for diagnostics, really */
2258 return pkt->length - 1;
2262 * Compress packet payload.
2265 unsigned char *newpayload;
2268 ssh->cscomp->compress(ssh->cs_comp_ctx, pkt->data + 5,
2270 &newpayload, &newlen)) {
2272 ssh2_pkt_adddata(pkt, newpayload, newlen);
2278 * Add padding. At least four bytes, and must also bring total
2279 * length (minus MAC) up to a multiple of the block size.
2280 * If pkt->forcepad is set, make sure the packet is at least that size
2283 cipherblk = ssh->cscipher ? ssh->cscipher->blksize : 8; /* block size */
2284 cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */
2286 unencrypted_prefix = (ssh->csmac && ssh->csmac_etm) ? 4 : 0;
2287 if (pkt->length + padding < pkt->forcepad)
2288 padding = pkt->forcepad - pkt->length;
2290 (cipherblk - (pkt->length - unencrypted_prefix + padding) % cipherblk)
2292 assert(padding <= 255);
2293 maclen = ssh->csmac ? ssh->csmac->len : 0;
2294 ssh2_pkt_ensure(pkt, pkt->length + padding + maclen);
2295 pkt->data[4] = padding;
2296 for (i = 0; i < padding; i++)
2297 pkt->data[pkt->length + i] = random_byte();
2298 PUT_32BIT(pkt->data, pkt->length + padding - 4);
2300 /* Encrypt length if the scheme requires it */
2301 if (ssh->cscipher && (ssh->cscipher->flags & SSH_CIPHER_SEPARATE_LENGTH)) {
2302 ssh->cscipher->encrypt_length(ssh->cs_cipher_ctx, pkt->data, 4,
2303 ssh->v2_outgoing_sequence);
2306 if (ssh->csmac && ssh->csmac_etm) {
2308 * OpenSSH-defined encrypt-then-MAC protocol.
2311 ssh->cscipher->encrypt(ssh->cs_cipher_ctx,
2312 pkt->data + 4, pkt->length + padding - 4);
2313 ssh->csmac->generate(ssh->cs_mac_ctx, pkt->data,
2314 pkt->length + padding,
2315 ssh->v2_outgoing_sequence);
2318 * SSH-2 standard protocol.
2321 ssh->csmac->generate(ssh->cs_mac_ctx, pkt->data,
2322 pkt->length + padding,
2323 ssh->v2_outgoing_sequence);
2325 ssh->cscipher->encrypt(ssh->cs_cipher_ctx,
2326 pkt->data, pkt->length + padding);
2329 ssh->v2_outgoing_sequence++; /* whether or not we MACed */
2330 pkt->encrypted_len = pkt->length + padding;
2332 /* Ready-to-send packet starts at pkt->data. We return length. */
2333 pkt->body = pkt->data;
2334 return pkt->length + padding + maclen;
2338 * Routines called from the main SSH code to send packets. There
2339 * are quite a few of these, because we have two separate
2340 * mechanisms for delaying the sending of packets:
2342 * - In order to send an IGNORE message and a password message in
2343 * a single fixed-length blob, we require the ability to
2344 * concatenate the encrypted forms of those two packets _into_ a
2345 * single blob and then pass it to our <network.h> transport
2346 * layer in one go. Hence, there's a deferment mechanism which
2347 * works after packet encryption.
2349 * - In order to avoid sending any connection-layer messages
2350 * during repeat key exchange, we have to queue up any such
2351 * outgoing messages _before_ they are encrypted (and in
2352 * particular before they're allocated sequence numbers), and
2353 * then send them once we've finished.
2355 * I call these mechanisms `defer' and `queue' respectively, so as
2356 * to distinguish them reasonably easily.
2358 * The functions send_noqueue() and defer_noqueue() free the packet
2359 * structure they are passed. Every outgoing packet goes through
2360 * precisely one of these functions in its life; packets passed to
2361 * ssh2_pkt_send() or ssh2_pkt_defer() either go straight to one of
2362 * these or get queued, and then when the queue is later emptied
2363 * the packets are all passed to defer_noqueue().
2365 * When using a CBC-mode cipher, it's necessary to ensure that an
2366 * attacker can't provide data to be encrypted using an IV that they
2367 * know. We ensure this by prefixing each packet that might contain
2368 * user data with an SSH_MSG_IGNORE. This is done using the deferral
2369 * mechanism, so in this case send_noqueue() ends up redirecting to
2370 * defer_noqueue(). If you don't like this inefficiency, don't use
2374 static void ssh2_pkt_defer_noqueue(Ssh, struct Packet *, int);
2375 static void ssh_pkt_defersend(Ssh);
2378 * Send an SSH-2 packet immediately, without queuing or deferring.
2380 static void ssh2_pkt_send_noqueue(Ssh ssh, struct Packet *pkt)
2384 if (ssh->cscipher != NULL && (ssh->cscipher->flags & SSH_CIPHER_IS_CBC)) {
2385 /* We need to send two packets, so use the deferral mechanism. */
2386 ssh2_pkt_defer_noqueue(ssh, pkt, FALSE);
2387 ssh_pkt_defersend(ssh);
2390 len = ssh2_pkt_construct(ssh, pkt);
2391 backlog = s_write(ssh, pkt->body, len);
2392 if (backlog > SSH_MAX_BACKLOG)
2393 ssh_throttle_all(ssh, 1, backlog);
2395 ssh->outgoing_data_size += pkt->encrypted_len;
2396 if (!ssh->kex_in_progress &&
2397 !ssh->bare_connection &&
2398 ssh->max_data_size != 0 &&
2399 ssh->outgoing_data_size > ssh->max_data_size)
2400 do_ssh2_transport(ssh, "too much data sent", -1, NULL);
2402 ssh_free_packet(pkt);
2406 * Defer an SSH-2 packet.
2408 static void ssh2_pkt_defer_noqueue(Ssh ssh, struct Packet *pkt, int noignore)
2411 if (ssh->cscipher != NULL && (ssh->cscipher->flags & SSH_CIPHER_IS_CBC) &&
2412 ssh->deferred_len == 0 && !noignore &&
2413 !(ssh->remote_bugs & BUG_CHOKES_ON_SSH2_IGNORE)) {
2415 * Interpose an SSH_MSG_IGNORE to ensure that user data don't
2416 * get encrypted with a known IV.
2418 struct Packet *ipkt = ssh2_pkt_init(SSH2_MSG_IGNORE);
2419 ssh2_pkt_addstring_start(ipkt);
2420 ssh2_pkt_defer_noqueue(ssh, ipkt, TRUE);
2422 len = ssh2_pkt_construct(ssh, pkt);
2423 if (ssh->deferred_len + len > ssh->deferred_size) {
2424 ssh->deferred_size = ssh->deferred_len + len + 128;
2425 ssh->deferred_send_data = sresize(ssh->deferred_send_data,
2429 memcpy(ssh->deferred_send_data + ssh->deferred_len, pkt->body, len);
2430 ssh->deferred_len += len;
2431 ssh->deferred_data_size += pkt->encrypted_len;
2432 ssh_free_packet(pkt);
2436 * Queue an SSH-2 packet.
2438 static void ssh2_pkt_queue(Ssh ssh, struct Packet *pkt)
2440 assert(ssh->queueing);
2442 if (ssh->queuelen >= ssh->queuesize) {
2443 ssh->queuesize = ssh->queuelen + 32;
2444 ssh->queue = sresize(ssh->queue, ssh->queuesize, struct Packet *);
2447 ssh->queue[ssh->queuelen++] = pkt;
2451 * Either queue or send a packet, depending on whether queueing is
2454 static void ssh2_pkt_send(Ssh ssh, struct Packet *pkt)
2457 ssh2_pkt_queue(ssh, pkt);
2459 ssh2_pkt_send_noqueue(ssh, pkt);
2463 * Either queue or defer a packet, depending on whether queueing is
2466 static void ssh2_pkt_defer(Ssh ssh, struct Packet *pkt)
2469 ssh2_pkt_queue(ssh, pkt);
2471 ssh2_pkt_defer_noqueue(ssh, pkt, FALSE);
2475 * Send the whole deferred data block constructed by
2476 * ssh2_pkt_defer() or SSH-1's defer_packet().
2478 * The expected use of the defer mechanism is that you call
2479 * ssh2_pkt_defer() a few times, then call ssh_pkt_defersend(). If
2480 * not currently queueing, this simply sets up deferred_send_data
2481 * and then sends it. If we _are_ currently queueing, the calls to
2482 * ssh2_pkt_defer() put the deferred packets on to the queue
2483 * instead, and therefore ssh_pkt_defersend() has no deferred data
2484 * to send. Hence, there's no need to make it conditional on
2487 static void ssh_pkt_defersend(Ssh ssh)
2490 backlog = s_write(ssh, ssh->deferred_send_data, ssh->deferred_len);
2491 ssh->deferred_len = ssh->deferred_size = 0;
2492 sfree(ssh->deferred_send_data);
2493 ssh->deferred_send_data = NULL;
2494 if (backlog > SSH_MAX_BACKLOG)
2495 ssh_throttle_all(ssh, 1, backlog);
2497 ssh->outgoing_data_size += ssh->deferred_data_size;
2498 if (!ssh->kex_in_progress &&
2499 !ssh->bare_connection &&
2500 ssh->max_data_size != 0 &&
2501 ssh->outgoing_data_size > ssh->max_data_size)
2502 do_ssh2_transport(ssh, "too much data sent", -1, NULL);
2503 ssh->deferred_data_size = 0;
2507 * Send a packet whose length needs to be disguised (typically
2508 * passwords or keyboard-interactive responses).
2510 static void ssh2_pkt_send_with_padding(Ssh ssh, struct Packet *pkt,
2516 * The simplest way to do this is to adjust the
2517 * variable-length padding field in the outgoing packet.
2519 * Currently compiled out, because some Cisco SSH servers
2520 * don't like excessively padded packets (bah, why's it
2523 pkt->forcepad = padsize;
2524 ssh2_pkt_send(ssh, pkt);
2529 * If we can't do that, however, an alternative approach is
2530 * to use the pkt_defer mechanism to bundle the packet
2531 * tightly together with an SSH_MSG_IGNORE such that their
2532 * combined length is a constant. So first we construct the
2533 * final form of this packet and defer its sending.
2535 ssh2_pkt_defer(ssh, pkt);
2538 * Now construct an SSH_MSG_IGNORE which includes a string
2539 * that's an exact multiple of the cipher block size. (If
2540 * the cipher is NULL so that the block size is
2541 * unavailable, we don't do this trick at all, because we
2542 * gain nothing by it.)
2544 if (ssh->cscipher &&
2545 !(ssh->remote_bugs & BUG_CHOKES_ON_SSH2_IGNORE)) {
2548 stringlen = (256 - ssh->deferred_len);
2549 stringlen += ssh->cscipher->blksize - 1;
2550 stringlen -= (stringlen % ssh->cscipher->blksize);
2553 * Temporarily disable actual compression, so we
2554 * can guarantee to get this string exactly the
2555 * length we want it. The compression-disabling
2556 * routine should return an integer indicating how
2557 * many bytes we should adjust our string length
2561 ssh->cscomp->disable_compression(ssh->cs_comp_ctx);
2563 pkt = ssh2_pkt_init(SSH2_MSG_IGNORE);
2564 ssh2_pkt_addstring_start(pkt);
2565 for (i = 0; i < stringlen; i++) {
2566 char c = (char) random_byte();
2567 ssh2_pkt_addstring_data(pkt, &c, 1);
2569 ssh2_pkt_defer(ssh, pkt);
2571 ssh_pkt_defersend(ssh);
2576 * Send all queued SSH-2 packets. We send them by means of
2577 * ssh2_pkt_defer_noqueue(), in case they included a pair of
2578 * packets that needed to be lumped together.
2580 static void ssh2_pkt_queuesend(Ssh ssh)
2584 assert(!ssh->queueing);
2586 for (i = 0; i < ssh->queuelen; i++)
2587 ssh2_pkt_defer_noqueue(ssh, ssh->queue[i], FALSE);
2590 ssh_pkt_defersend(ssh);
2594 void bndebug(char *string, Bignum b)
2598 p = ssh2_mpint_fmt(b, &len);
2599 debug(("%s", string));
2600 for (i = 0; i < len; i++)
2601 debug((" %02x", p[i]));
2607 static void hash_mpint(const struct ssh_hash *h, void *s, Bignum b)
2611 p = ssh2_mpint_fmt(b, &len);
2612 hash_string(h, s, p, len);
2617 * Packet decode functions for both SSH-1 and SSH-2.
2619 static unsigned long ssh_pkt_getuint32(struct Packet *pkt)
2621 unsigned long value;
2622 if (pkt->length - pkt->savedpos < 4)
2623 return 0; /* arrgh, no way to decline (FIXME?) */
2624 value = GET_32BIT(pkt->body + pkt->savedpos);
2628 static int ssh2_pkt_getbool(struct Packet *pkt)
2630 unsigned long value;
2631 if (pkt->length - pkt->savedpos < 1)
2632 return 0; /* arrgh, no way to decline (FIXME?) */
2633 value = pkt->body[pkt->savedpos] != 0;
2637 static void ssh_pkt_getstring(struct Packet *pkt, char **p, int *length)
2642 if (pkt->length - pkt->savedpos < 4)
2644 len = toint(GET_32BIT(pkt->body + pkt->savedpos));
2649 if (pkt->length - pkt->savedpos < *length)
2651 *p = (char *)(pkt->body + pkt->savedpos);
2652 pkt->savedpos += *length;
2654 static void *ssh_pkt_getdata(struct Packet *pkt, int length)
2656 if (pkt->length - pkt->savedpos < length)
2658 pkt->savedpos += length;
2659 return pkt->body + (pkt->savedpos - length);
2661 static int ssh1_pkt_getrsakey(struct Packet *pkt, struct RSAKey *key,
2662 const unsigned char **keystr)
2666 j = makekey(pkt->body + pkt->savedpos,
2667 pkt->length - pkt->savedpos,
2674 assert(pkt->savedpos < pkt->length);
2678 static Bignum ssh1_pkt_getmp(struct Packet *pkt)
2683 j = ssh1_read_bignum(pkt->body + pkt->savedpos,
2684 pkt->length - pkt->savedpos, &b);
2692 static Bignum ssh2_pkt_getmp(struct Packet *pkt)
2698 ssh_pkt_getstring(pkt, &p, &length);
2703 b = bignum_from_bytes((unsigned char *)p, length);
2708 * Helper function to add an SSH-2 signature blob to a packet.
2709 * Expects to be shown the public key blob as well as the signature
2710 * blob. Normally works just like ssh2_pkt_addstring, but will
2711 * fiddle with the signature packet if necessary for
2712 * BUG_SSH2_RSA_PADDING.
2714 static void ssh2_add_sigblob(Ssh ssh, struct Packet *pkt,
2715 void *pkblob_v, int pkblob_len,
2716 void *sigblob_v, int sigblob_len)
2718 unsigned char *pkblob = (unsigned char *)pkblob_v;
2719 unsigned char *sigblob = (unsigned char *)sigblob_v;
2721 /* dmemdump(pkblob, pkblob_len); */
2722 /* dmemdump(sigblob, sigblob_len); */
2725 * See if this is in fact an ssh-rsa signature and a buggy
2726 * server; otherwise we can just do this the easy way.
2728 if ((ssh->remote_bugs & BUG_SSH2_RSA_PADDING) && pkblob_len > 4+7+4 &&
2729 (GET_32BIT(pkblob) == 7 && !memcmp(pkblob+4, "ssh-rsa", 7))) {
2730 int pos, len, siglen;
2733 * Find the byte length of the modulus.
2736 pos = 4+7; /* skip over "ssh-rsa" */
2737 len = toint(GET_32BIT(pkblob+pos)); /* get length of exponent */
2738 if (len < 0 || len > pkblob_len - pos - 4)
2740 pos += 4 + len; /* skip over exponent */
2741 if (pkblob_len - pos < 4)
2743 len = toint(GET_32BIT(pkblob+pos)); /* find length of modulus */
2744 if (len < 0 || len > pkblob_len - pos - 4)
2746 pos += 4; /* find modulus itself */
2747 while (len > 0 && pkblob[pos] == 0)
2749 /* debug(("modulus length is %d\n", len)); */
2752 * Now find the signature integer.
2754 pos = 4+7; /* skip over "ssh-rsa" */
2755 if (sigblob_len < pos+4)
2757 siglen = toint(GET_32BIT(sigblob+pos));
2758 if (siglen != sigblob_len - pos - 4)
2760 /* debug(("signature length is %d\n", siglen)); */
2762 if (len != siglen) {
2763 unsigned char newlen[4];
2764 ssh2_pkt_addstring_start(pkt);
2765 ssh2_pkt_addstring_data(pkt, (char *)sigblob, pos);
2766 /* dmemdump(sigblob, pos); */
2767 pos += 4; /* point to start of actual sig */
2768 PUT_32BIT(newlen, len);
2769 ssh2_pkt_addstring_data(pkt, (char *)newlen, 4);
2770 /* dmemdump(newlen, 4); */
2772 while (len-- > siglen) {
2773 ssh2_pkt_addstring_data(pkt, (char *)newlen, 1);
2774 /* dmemdump(newlen, 1); */
2776 ssh2_pkt_addstring_data(pkt, (char *)(sigblob+pos), siglen);
2777 /* dmemdump(sigblob+pos, siglen); */
2781 /* Otherwise fall through and do it the easy way. We also come
2782 * here as a fallback if we discover above that the key blob
2783 * is misformatted in some way. */
2787 ssh2_pkt_addstring_start(pkt);
2788 ssh2_pkt_addstring_data(pkt, (char *)sigblob, sigblob_len);
2792 * Examine the remote side's version string and compare it against
2793 * a list of known buggy implementations.
2795 static void ssh_detect_bugs(Ssh ssh, char *vstring)
2797 char *imp; /* pointer to implementation part */
2799 imp += strcspn(imp, "-");
2801 imp += strcspn(imp, "-");
2804 ssh->remote_bugs = 0;
2807 * General notes on server version strings:
2808 * - Not all servers reporting "Cisco-1.25" have all the bugs listed
2809 * here -- in particular, we've heard of one that's perfectly happy
2810 * with SSH1_MSG_IGNOREs -- but this string never seems to change,
2811 * so we can't distinguish them.
2813 if (conf_get_int(ssh->conf, CONF_sshbug_ignore1) == FORCE_ON ||
2814 (conf_get_int(ssh->conf, CONF_sshbug_ignore1) == AUTO &&
2815 (!strcmp(imp, "1.2.18") || !strcmp(imp, "1.2.19") ||
2816 !strcmp(imp, "1.2.20") || !strcmp(imp, "1.2.21") ||
2817 !strcmp(imp, "1.2.22") || !strcmp(imp, "Cisco-1.25") ||
2818 !strcmp(imp, "OSU_1.4alpha3") || !strcmp(imp, "OSU_1.5alpha4")))) {
2820 * These versions don't support SSH1_MSG_IGNORE, so we have
2821 * to use a different defence against password length
2824 ssh->remote_bugs |= BUG_CHOKES_ON_SSH1_IGNORE;
2825 logevent("We believe remote version has SSH-1 ignore bug");
2828 if (conf_get_int(ssh->conf, CONF_sshbug_plainpw1) == FORCE_ON ||
2829 (conf_get_int(ssh->conf, CONF_sshbug_plainpw1) == AUTO &&
2830 (!strcmp(imp, "Cisco-1.25") || !strcmp(imp, "OSU_1.4alpha3")))) {
2832 * These versions need a plain password sent; they can't
2833 * handle having a null and a random length of data after
2836 ssh->remote_bugs |= BUG_NEEDS_SSH1_PLAIN_PASSWORD;
2837 logevent("We believe remote version needs a plain SSH-1 password");
2840 if (conf_get_int(ssh->conf, CONF_sshbug_rsa1) == FORCE_ON ||
2841 (conf_get_int(ssh->conf, CONF_sshbug_rsa1) == AUTO &&
2842 (!strcmp(imp, "Cisco-1.25")))) {
2844 * These versions apparently have no clue whatever about
2845 * RSA authentication and will panic and die if they see
2846 * an AUTH_RSA message.
2848 ssh->remote_bugs |= BUG_CHOKES_ON_RSA;
2849 logevent("We believe remote version can't handle SSH-1 RSA authentication");
2852 if (conf_get_int(ssh->conf, CONF_sshbug_hmac2) == FORCE_ON ||
2853 (conf_get_int(ssh->conf, CONF_sshbug_hmac2) == AUTO &&
2854 !wc_match("* VShell", imp) &&
2855 (wc_match("2.1.0*", imp) || wc_match("2.0.*", imp) ||
2856 wc_match("2.2.0*", imp) || wc_match("2.3.0*", imp) ||
2857 wc_match("2.1 *", imp)))) {
2859 * These versions have the HMAC bug.
2861 ssh->remote_bugs |= BUG_SSH2_HMAC;
2862 logevent("We believe remote version has SSH-2 HMAC bug");
2865 if (conf_get_int(ssh->conf, CONF_sshbug_derivekey2) == FORCE_ON ||
2866 (conf_get_int(ssh->conf, CONF_sshbug_derivekey2) == AUTO &&
2867 !wc_match("* VShell", imp) &&
2868 (wc_match("2.0.0*", imp) || wc_match("2.0.10*", imp) ))) {
2870 * These versions have the key-derivation bug (failing to
2871 * include the literal shared secret in the hashes that
2872 * generate the keys).
2874 ssh->remote_bugs |= BUG_SSH2_DERIVEKEY;
2875 logevent("We believe remote version has SSH-2 key-derivation bug");
2878 if (conf_get_int(ssh->conf, CONF_sshbug_rsapad2) == FORCE_ON ||
2879 (conf_get_int(ssh->conf, CONF_sshbug_rsapad2) == AUTO &&
2880 (wc_match("OpenSSH_2.[5-9]*", imp) ||
2881 wc_match("OpenSSH_3.[0-2]*", imp) ||
2882 wc_match("mod_sftp/0.[0-8]*", imp) ||
2883 wc_match("mod_sftp/0.9.[0-8]", imp)))) {
2885 * These versions have the SSH-2 RSA padding bug.
2887 ssh->remote_bugs |= BUG_SSH2_RSA_PADDING;
2888 logevent("We believe remote version has SSH-2 RSA padding bug");
2891 if (conf_get_int(ssh->conf, CONF_sshbug_pksessid2) == FORCE_ON ||
2892 (conf_get_int(ssh->conf, CONF_sshbug_pksessid2) == AUTO &&
2893 wc_match("OpenSSH_2.[0-2]*", imp))) {
2895 * These versions have the SSH-2 session-ID bug in
2896 * public-key authentication.
2898 ssh->remote_bugs |= BUG_SSH2_PK_SESSIONID;
2899 logevent("We believe remote version has SSH-2 public-key-session-ID bug");
2902 if (conf_get_int(ssh->conf, CONF_sshbug_rekey2) == FORCE_ON ||
2903 (conf_get_int(ssh->conf, CONF_sshbug_rekey2) == AUTO &&
2904 (wc_match("DigiSSH_2.0", imp) ||
2905 wc_match("OpenSSH_2.[0-4]*", imp) ||
2906 wc_match("OpenSSH_2.5.[0-3]*", imp) ||
2907 wc_match("Sun_SSH_1.0", imp) ||
2908 wc_match("Sun_SSH_1.0.1", imp) ||
2909 /* All versions <= 1.2.6 (they changed their format in 1.2.7) */
2910 wc_match("WeOnlyDo-*", imp)))) {
2912 * These versions have the SSH-2 rekey bug.
2914 ssh->remote_bugs |= BUG_SSH2_REKEY;
2915 logevent("We believe remote version has SSH-2 rekey bug");
2918 if (conf_get_int(ssh->conf, CONF_sshbug_maxpkt2) == FORCE_ON ||
2919 (conf_get_int(ssh->conf, CONF_sshbug_maxpkt2) == AUTO &&
2920 (wc_match("1.36_sshlib GlobalSCAPE", imp) ||
2921 wc_match("1.36 sshlib: GlobalScape", imp)))) {
2923 * This version ignores our makpkt and needs to be throttled.
2925 ssh->remote_bugs |= BUG_SSH2_MAXPKT;
2926 logevent("We believe remote version ignores SSH-2 maximum packet size");
2929 if (conf_get_int(ssh->conf, CONF_sshbug_ignore2) == FORCE_ON) {
2931 * Servers that don't support SSH2_MSG_IGNORE. Currently,
2932 * none detected automatically.
2934 ssh->remote_bugs |= BUG_CHOKES_ON_SSH2_IGNORE;
2935 logevent("We believe remote version has SSH-2 ignore bug");
2938 if (conf_get_int(ssh->conf, CONF_sshbug_oldgex2) == FORCE_ON ||
2939 (conf_get_int(ssh->conf, CONF_sshbug_oldgex2) == AUTO &&
2940 (wc_match("OpenSSH_2.[235]*", imp)))) {
2942 * These versions only support the original (pre-RFC4419)
2943 * SSH-2 GEX request, and disconnect with a protocol error if
2944 * we use the newer version.
2946 ssh->remote_bugs |= BUG_SSH2_OLDGEX;
2947 logevent("We believe remote version has outdated SSH-2 GEX");
2950 if (conf_get_int(ssh->conf, CONF_sshbug_winadj) == FORCE_ON) {
2952 * Servers that don't support our winadj request for one
2953 * reason or another. Currently, none detected automatically.
2955 ssh->remote_bugs |= BUG_CHOKES_ON_WINADJ;
2956 logevent("We believe remote version has winadj bug");
2959 if (conf_get_int(ssh->conf, CONF_sshbug_chanreq) == FORCE_ON ||
2960 (conf_get_int(ssh->conf, CONF_sshbug_chanreq) == AUTO &&
2961 (wc_match("OpenSSH_[2-5].*", imp) ||
2962 wc_match("OpenSSH_6.[0-6]*", imp) ||
2963 wc_match("dropbear_0.[2-4][0-9]*", imp) ||
2964 wc_match("dropbear_0.5[01]*", imp)))) {
2966 * These versions have the SSH-2 channel request bug.
2967 * OpenSSH 6.7 and above do not:
2968 * https://bugzilla.mindrot.org/show_bug.cgi?id=1818
2969 * dropbear_0.52 and above do not:
2970 * https://secure.ucc.asn.au/hg/dropbear/rev/cd02449b709c
2972 ssh->remote_bugs |= BUG_SENDS_LATE_REQUEST_REPLY;
2973 logevent("We believe remote version has SSH-2 channel request bug");
2978 * The `software version' part of an SSH version string is required
2979 * to contain no spaces or minus signs.
2981 static void ssh_fix_verstring(char *str)
2983 /* Eat "<protoversion>-". */
2984 while (*str && *str != '-') str++;
2985 assert(*str == '-'); str++;
2987 /* Convert minus signs and spaces in the remaining string into
2990 if (*str == '-' || *str == ' ')
2997 * Send an appropriate SSH version string.
2999 static void ssh_send_verstring(Ssh ssh, const char *protoname, char *svers)
3003 if (ssh->version == 2) {
3005 * Construct a v2 version string.
3007 verstring = dupprintf("%s2.0-%s\015\012", protoname, sshver);
3010 * Construct a v1 version string.
3012 assert(!strcmp(protoname, "SSH-")); /* no v1 bare connection protocol */
3013 verstring = dupprintf("SSH-%s-%s\012",
3014 (ssh_versioncmp(svers, "1.5") <= 0 ?
3019 ssh_fix_verstring(verstring + strlen(protoname));
3021 if (ssh->version == 2) {
3024 * Record our version string.
3026 len = strcspn(verstring, "\015\012");
3027 ssh->v_c = snewn(len + 1, char);
3028 memcpy(ssh->v_c, verstring, len);
3032 logeventf(ssh, "We claim version: %.*s",
3033 strcspn(verstring, "\015\012"), verstring);
3034 s_write(ssh, verstring, strlen(verstring));
3038 static int do_ssh_init(Ssh ssh, unsigned char c)
3040 static const char protoname[] = "SSH-";
3042 struct do_ssh_init_state {
3051 crState(do_ssh_init_state);
3055 /* Search for a line beginning with the protocol name prefix in
3058 for (s->i = 0; protoname[s->i]; s->i++) {
3059 if ((char)c != protoname[s->i]) goto no;
3069 s->vstrsize = sizeof(protoname) + 16;
3070 s->vstring = snewn(s->vstrsize, char);
3071 strcpy(s->vstring, protoname);
3072 s->vslen = strlen(protoname);
3075 if (s->vslen >= s->vstrsize - 1) {
3077 s->vstring = sresize(s->vstring, s->vstrsize, char);
3079 s->vstring[s->vslen++] = c;
3082 s->version[s->i] = '\0';
3084 } else if (s->i < sizeof(s->version) - 1)
3085 s->version[s->i++] = c;
3086 } else if (c == '\012')
3088 crReturn(1); /* get another char */
3091 ssh->agentfwd_enabled = FALSE;
3092 ssh->rdpkt2_state.incoming_sequence = 0;
3094 s->vstring[s->vslen] = 0;
3095 s->vstring[strcspn(s->vstring, "\015\012")] = '\0';/* remove EOL chars */
3096 logeventf(ssh, "Server version: %s", s->vstring);
3097 ssh_detect_bugs(ssh, s->vstring);
3100 * Decide which SSH protocol version to support.
3103 /* Anything strictly below "2.0" means protocol 1 is supported. */
3104 s->proto1 = ssh_versioncmp(s->version, "2.0") < 0;
3105 /* Anything greater or equal to "1.99" means protocol 2 is supported. */
3106 s->proto2 = ssh_versioncmp(s->version, "1.99") >= 0;
3108 if (conf_get_int(ssh->conf, CONF_sshprot) == 0 && !s->proto1) {
3109 bombout(("SSH protocol version 1 required by configuration but "
3110 "not provided by server"));
3113 if (conf_get_int(ssh->conf, CONF_sshprot) == 3 && !s->proto2) {
3114 bombout(("SSH protocol version 2 required by configuration but "
3115 "not provided by server"));
3119 if (s->proto2 && (conf_get_int(ssh->conf, CONF_sshprot) >= 2 || !s->proto1))
3124 logeventf(ssh, "Using SSH protocol version %d", ssh->version);
3126 /* Send the version string, if we haven't already */
3127 if (conf_get_int(ssh->conf, CONF_sshprot) != 3)
3128 ssh_send_verstring(ssh, protoname, s->version);
3130 if (ssh->version == 2) {
3133 * Record their version string.
3135 len = strcspn(s->vstring, "\015\012");
3136 ssh->v_s = snewn(len + 1, char);
3137 memcpy(ssh->v_s, s->vstring, len);
3141 * Initialise SSH-2 protocol.
3143 ssh->protocol = ssh2_protocol;
3144 ssh2_protocol_setup(ssh);
3145 ssh->s_rdpkt = ssh2_rdpkt;
3148 * Initialise SSH-1 protocol.
3150 ssh->protocol = ssh1_protocol;
3151 ssh1_protocol_setup(ssh);
3152 ssh->s_rdpkt = ssh1_rdpkt;
3154 if (ssh->version == 2)
3155 do_ssh2_transport(ssh, NULL, -1, NULL);
3157 update_specials_menu(ssh->frontend);
3158 ssh->state = SSH_STATE_BEFORE_SIZE;
3159 ssh->pinger = pinger_new(ssh->conf, &ssh_backend, ssh);
3166 static int do_ssh_connection_init(Ssh ssh, unsigned char c)
3169 * Ordinary SSH begins with the banner "SSH-x.y-...". This is just
3170 * the ssh-connection part, extracted and given a trivial binary
3171 * packet protocol, so we replace 'SSH-' at the start with a new
3172 * name. In proper SSH style (though of course this part of the
3173 * proper SSH protocol _isn't_ subject to this kind of
3174 * DNS-domain-based extension), we define the new name in our
3177 static const char protoname[] =
3178 "SSHCONNECTION@putty.projects.tartarus.org-";
3180 struct do_ssh_connection_init_state {
3188 crState(do_ssh_connection_init_state);
3192 /* Search for a line beginning with the protocol name prefix in
3195 for (s->i = 0; protoname[s->i]; s->i++) {
3196 if ((char)c != protoname[s->i]) goto no;
3206 s->vstrsize = sizeof(protoname) + 16;
3207 s->vstring = snewn(s->vstrsize, char);
3208 strcpy(s->vstring, protoname);
3209 s->vslen = strlen(protoname);
3212 if (s->vslen >= s->vstrsize - 1) {
3214 s->vstring = sresize(s->vstring, s->vstrsize, char);
3216 s->vstring[s->vslen++] = c;
3219 s->version[s->i] = '\0';
3221 } else if (s->i < sizeof(s->version) - 1)
3222 s->version[s->i++] = c;
3223 } else if (c == '\012')
3225 crReturn(1); /* get another char */
3228 ssh->agentfwd_enabled = FALSE;
3229 ssh->rdpkt2_bare_state.incoming_sequence = 0;
3231 s->vstring[s->vslen] = 0;
3232 s->vstring[strcspn(s->vstring, "\015\012")] = '\0';/* remove EOL chars */
3233 logeventf(ssh, "Server version: %s", s->vstring);
3234 ssh_detect_bugs(ssh, s->vstring);
3237 * Decide which SSH protocol version to support. This is easy in
3238 * bare ssh-connection mode: only 2.0 is legal.
3240 if (ssh_versioncmp(s->version, "2.0") < 0) {
3241 bombout(("Server announces compatibility with SSH-1 in bare ssh-connection protocol"));
3244 if (conf_get_int(ssh->conf, CONF_sshprot) == 0) {
3245 bombout(("Bare ssh-connection protocol cannot be run in SSH-1-only mode"));
3251 logeventf(ssh, "Using bare ssh-connection protocol");
3253 /* Send the version string, if we haven't already */
3254 ssh_send_verstring(ssh, protoname, s->version);
3257 * Initialise bare connection protocol.
3259 ssh->protocol = ssh2_bare_connection_protocol;
3260 ssh2_bare_connection_protocol_setup(ssh);
3261 ssh->s_rdpkt = ssh2_bare_connection_rdpkt;
3263 update_specials_menu(ssh->frontend);
3264 ssh->state = SSH_STATE_BEFORE_SIZE;
3265 ssh->pinger = pinger_new(ssh->conf, &ssh_backend, ssh);
3268 * Get authconn (really just conn) under way.
3270 do_ssh2_authconn(ssh, NULL, 0, NULL);
3277 static void ssh_process_incoming_data(Ssh ssh,
3278 const unsigned char **data, int *datalen)
3280 struct Packet *pktin;
3282 pktin = ssh->s_rdpkt(ssh, data, datalen);
3284 ssh->protocol(ssh, NULL, 0, pktin);
3285 ssh_free_packet(pktin);
3289 static void ssh_queue_incoming_data(Ssh ssh,
3290 const unsigned char **data, int *datalen)
3292 bufchain_add(&ssh->queued_incoming_data, *data, *datalen);
3297 static void ssh_process_queued_incoming_data(Ssh ssh)
3300 const unsigned char *data;
3303 while (!ssh->frozen && bufchain_size(&ssh->queued_incoming_data)) {
3304 bufchain_prefix(&ssh->queued_incoming_data, &vdata, &len);
3308 while (!ssh->frozen && len > 0)
3309 ssh_process_incoming_data(ssh, &data, &len);
3312 bufchain_consume(&ssh->queued_incoming_data, origlen - len);
3316 static void ssh_set_frozen(Ssh ssh, int frozen)
3319 sk_set_frozen(ssh->s, frozen);
3320 ssh->frozen = frozen;
3323 static void ssh_gotdata(Ssh ssh, const unsigned char *data, int datalen)
3325 /* Log raw data, if we're in that mode. */
3327 log_packet(ssh->logctx, PKT_INCOMING, -1, NULL, data, datalen,
3328 0, NULL, NULL, 0, NULL);
3330 crBegin(ssh->ssh_gotdata_crstate);
3333 * To begin with, feed the characters one by one to the
3334 * protocol initialisation / selection function do_ssh_init().
3335 * When that returns 0, we're done with the initial greeting
3336 * exchange and can move on to packet discipline.
3339 int ret; /* need not be kept across crReturn */
3341 crReturnV; /* more data please */
3342 ret = ssh->do_ssh_init(ssh, *data);
3350 * We emerge from that loop when the initial negotiation is
3351 * over and we have selected an s_rdpkt function. Now pass
3352 * everything to s_rdpkt, and then pass the resulting packets
3353 * to the proper protocol handler.
3357 while (bufchain_size(&ssh->queued_incoming_data) > 0 || datalen > 0) {
3359 ssh_queue_incoming_data(ssh, &data, &datalen);
3360 /* This uses up all data and cannot cause anything interesting
3361 * to happen; indeed, for anything to happen at all, we must
3362 * return, so break out. */
3364 } else if (bufchain_size(&ssh->queued_incoming_data) > 0) {
3365 /* This uses up some or all data, and may freeze the
3367 ssh_process_queued_incoming_data(ssh);
3369 /* This uses up some or all data, and may freeze the
3371 ssh_process_incoming_data(ssh, &data, &datalen);
3373 /* FIXME this is probably EBW. */
3374 if (ssh->state == SSH_STATE_CLOSED)
3377 /* We're out of data. Go and get some more. */
3383 static int ssh_do_close(Ssh ssh, int notify_exit)
3386 struct ssh_channel *c;
3388 ssh->state = SSH_STATE_CLOSED;
3389 expire_timer_context(ssh);
3394 notify_remote_exit(ssh->frontend);
3399 * Now we must shut down any port- and X-forwarded channels going
3400 * through this connection.
3402 if (ssh->channels) {
3403 while (NULL != (c = index234(ssh->channels, 0))) {
3406 x11_close(c->u.x11.xconn);
3409 case CHAN_SOCKDATA_DORMANT:
3410 pfd_close(c->u.pfd.pf);
3413 del234(ssh->channels, c); /* moving next one to index 0 */
3414 if (ssh->version == 2)
3415 bufchain_clear(&c->v.v2.outbuffer);
3420 * Go through port-forwardings, and close any associated
3421 * listening sockets.
3423 if (ssh->portfwds) {
3424 struct ssh_portfwd *pf;
3425 while (NULL != (pf = index234(ssh->portfwds, 0))) {
3426 /* Dispose of any listening socket. */
3428 pfl_terminate(pf->local);
3429 del234(ssh->portfwds, pf); /* moving next one to index 0 */
3432 freetree234(ssh->portfwds);
3433 ssh->portfwds = NULL;
3437 * Also stop attempting to connection-share.
3439 if (ssh->connshare) {
3440 sharestate_free(ssh->connshare);
3441 ssh->connshare = NULL;
3447 static void ssh_socket_log(Plug plug, int type, SockAddr addr, int port,
3448 const char *error_msg, int error_code)
3450 Ssh ssh = (Ssh) plug;
3451 char addrbuf[256], *msg;
3453 if (ssh->attempting_connshare) {
3455 * While we're attempting connection sharing, don't loudly log
3456 * everything that happens. Real TCP connections need to be
3457 * logged when we _start_ trying to connect, because it might
3458 * be ages before they respond if something goes wrong; but
3459 * connection sharing is local and quick to respond, and it's
3460 * sufficient to simply wait and see whether it worked
3464 sk_getaddr(addr, addrbuf, lenof(addrbuf));
3467 if (sk_addr_needs_port(addr)) {
3468 msg = dupprintf("Connecting to %s port %d", addrbuf, port);
3470 msg = dupprintf("Connecting to %s", addrbuf);
3473 msg = dupprintf("Failed to connect to %s: %s", addrbuf, error_msg);
3481 void ssh_connshare_log(Ssh ssh, int event, const char *logtext,
3482 const char *ds_err, const char *us_err)
3484 if (event == SHARE_NONE) {
3485 /* In this case, 'logtext' is an error message indicating a
3486 * reason why connection sharing couldn't be set up _at all_.
3487 * Failing that, ds_err and us_err indicate why we couldn't be
3488 * a downstream and an upstream respectively. */
3490 logeventf(ssh, "Could not set up connection sharing: %s", logtext);
3493 logeventf(ssh, "Could not set up connection sharing"
3494 " as downstream: %s", ds_err);
3496 logeventf(ssh, "Could not set up connection sharing"
3497 " as upstream: %s", us_err);
3499 } else if (event == SHARE_DOWNSTREAM) {
3500 /* In this case, 'logtext' is a local endpoint address */
3501 logeventf(ssh, "Using existing shared connection at %s", logtext);
3502 /* Also we should mention this in the console window to avoid
3503 * confusing users as to why this window doesn't behave the
3505 if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
3506 c_write_str(ssh,"Reusing a shared connection to this server.\r\n");
3508 } else if (event == SHARE_UPSTREAM) {
3509 /* In this case, 'logtext' is a local endpoint address too */
3510 logeventf(ssh, "Sharing this connection at %s", logtext);
3514 static int ssh_closing(Plug plug, const char *error_msg, int error_code,
3517 Ssh ssh = (Ssh) plug;
3518 int need_notify = ssh_do_close(ssh, FALSE);
3521 if (!ssh->close_expected)
3522 error_msg = "Server unexpectedly closed network connection";
3524 error_msg = "Server closed network connection";
3527 if (ssh->close_expected && ssh->clean_exit && ssh->exitcode < 0)
3531 notify_remote_exit(ssh->frontend);
3534 logevent(error_msg);
3535 if (!ssh->close_expected || !ssh->clean_exit)
3536 connection_fatal(ssh->frontend, "%s", error_msg);
3540 static int ssh_receive(Plug plug, int urgent, char *data, int len)
3542 Ssh ssh = (Ssh) plug;
3543 ssh_gotdata(ssh, (unsigned char *)data, len);
3544 if (ssh->state == SSH_STATE_CLOSED) {
3545 ssh_do_close(ssh, TRUE);
3551 static void ssh_sent(Plug plug, int bufsize)
3553 Ssh ssh = (Ssh) plug;
3555 * If the send backlog on the SSH socket itself clears, we
3556 * should unthrottle the whole world if it was throttled.
3558 if (bufsize < SSH_MAX_BACKLOG)
3559 ssh_throttle_all(ssh, 0, bufsize);
3562 static void ssh_hostport_setup(const char *host, int port, Conf *conf,
3563 char **savedhost, int *savedport,
3566 char *loghost = conf_get_str(conf, CONF_loghost);
3568 *loghost_ret = loghost;
3574 tmphost = dupstr(loghost);
3575 *savedport = 22; /* default ssh port */
3578 * A colon suffix on the hostname string also lets us affect
3579 * savedport. (Unless there are multiple colons, in which case
3580 * we assume this is an unbracketed IPv6 literal.)
3582 colon = host_strrchr(tmphost, ':');
3583 if (colon && colon == host_strchr(tmphost, ':')) {
3586 *savedport = atoi(colon);
3589 *savedhost = host_strduptrim(tmphost);
3592 *savedhost = host_strduptrim(host);
3594 port = 22; /* default ssh port */
3599 static int ssh_test_for_upstream(const char *host, int port, Conf *conf)
3605 random_ref(); /* platform may need this to determine share socket name */
3606 ssh_hostport_setup(host, port, conf, &savedhost, &savedport, NULL);
3607 ret = ssh_share_test_for_upstream(savedhost, savedport, conf);
3615 * Connect to specified host and port.
3616 * Returns an error message, or NULL on success.
3617 * Also places the canonical host name into `realhost'. It must be
3618 * freed by the caller.
3620 static const char *connect_to_host(Ssh ssh, const char *host, int port,
3621 char **realhost, int nodelay, int keepalive)
3623 static const struct plug_function_table fn_table = {
3634 int addressfamily, sshprot;
3636 ssh_hostport_setup(host, port, ssh->conf,
3637 &ssh->savedhost, &ssh->savedport, &loghost);
3639 ssh->fn = &fn_table; /* make 'ssh' usable as a Plug */
3642 * Try connection-sharing, in case that means we don't open a
3643 * socket after all. ssh_connection_sharing_init will connect to a
3644 * previously established upstream if it can, and failing that,
3645 * establish a listening socket for _us_ to be the upstream. In
3646 * the latter case it will return NULL just as if it had done
3647 * nothing, because here we only need to care if we're a
3648 * downstream and need to do our connection setup differently.
3650 ssh->connshare = NULL;
3651 ssh->attempting_connshare = TRUE; /* affects socket logging behaviour */
3652 ssh->s = ssh_connection_sharing_init(ssh->savedhost, ssh->savedport,
3653 ssh->conf, ssh, &ssh->connshare);
3654 ssh->attempting_connshare = FALSE;
3655 if (ssh->s != NULL) {
3657 * We are a downstream.
3659 ssh->bare_connection = TRUE;
3660 ssh->do_ssh_init = do_ssh_connection_init;
3661 ssh->fullhostname = NULL;
3662 *realhost = dupstr(host); /* best we can do */
3665 * We're not a downstream, so open a normal socket.
3667 ssh->do_ssh_init = do_ssh_init;
3672 addressfamily = conf_get_int(ssh->conf, CONF_addressfamily);
3673 logeventf(ssh, "Looking up host \"%s\"%s", host,
3674 (addressfamily == ADDRTYPE_IPV4 ? " (IPv4)" :
3675 (addressfamily == ADDRTYPE_IPV6 ? " (IPv6)" : "")));
3676 addr = name_lookup(host, port, realhost, ssh->conf, addressfamily);
3677 if ((err = sk_addr_error(addr)) != NULL) {
3681 ssh->fullhostname = dupstr(*realhost); /* save in case of GSSAPI */
3683 ssh->s = new_connection(addr, *realhost, port,
3684 0, 1, nodelay, keepalive,
3685 (Plug) ssh, ssh->conf);
3686 if ((err = sk_socket_error(ssh->s)) != NULL) {
3688 notify_remote_exit(ssh->frontend);
3694 * If the SSH version number's fixed, set it now, and if it's SSH-2,
3695 * send the version string too.
3697 sshprot = conf_get_int(ssh->conf, CONF_sshprot);
3700 if (sshprot == 3 && !ssh->bare_connection) {
3702 ssh_send_verstring(ssh, "SSH-", NULL);
3706 * loghost, if configured, overrides realhost.
3710 *realhost = dupstr(loghost);
3717 * Throttle or unthrottle the SSH connection.
3719 static void ssh_throttle_conn(Ssh ssh, int adjust)
3721 int old_count = ssh->conn_throttle_count;
3722 ssh->conn_throttle_count += adjust;
3723 assert(ssh->conn_throttle_count >= 0);
3724 if (ssh->conn_throttle_count && !old_count) {
3725 ssh_set_frozen(ssh, 1);
3726 } else if (!ssh->conn_throttle_count && old_count) {
3727 ssh_set_frozen(ssh, 0);
3732 * Throttle or unthrottle _all_ local data streams (for when sends
3733 * on the SSH connection itself back up).
3735 static void ssh_throttle_all(Ssh ssh, int enable, int bufsize)
3738 struct ssh_channel *c;
3740 if (enable == ssh->throttled_all)
3742 ssh->throttled_all = enable;
3743 ssh->overall_bufsize = bufsize;
3746 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
3748 case CHAN_MAINSESSION:
3750 * This is treated separately, outside the switch.
3754 x11_override_throttle(c->u.x11.xconn, enable);
3757 /* Agent channels require no buffer management. */
3760 pfd_override_throttle(c->u.pfd.pf, enable);
3766 static void ssh_agent_callback(void *sshv, void *reply, int replylen)
3768 Ssh ssh = (Ssh) sshv;
3770 ssh->agent_response = reply;
3771 ssh->agent_response_len = replylen;
3773 if (ssh->version == 1)
3774 do_ssh1_login(ssh, NULL, -1, NULL);
3776 do_ssh2_authconn(ssh, NULL, -1, NULL);
3779 static void ssh_dialog_callback(void *sshv, int ret)
3781 Ssh ssh = (Ssh) sshv;
3783 ssh->user_response = ret;
3785 if (ssh->version == 1)
3786 do_ssh1_login(ssh, NULL, -1, NULL);
3788 do_ssh2_transport(ssh, NULL, -1, NULL);
3791 * This may have unfrozen the SSH connection, so do a
3794 ssh_process_queued_incoming_data(ssh);
3797 static void ssh_agentf_callback(void *cv, void *reply, int replylen)
3799 struct ssh_channel *c = (struct ssh_channel *)cv;
3801 const void *sentreply = reply;
3803 c->u.a.outstanding_requests--;
3805 /* Fake SSH_AGENT_FAILURE. */
3806 sentreply = "\0\0\0\1\5";
3809 if (ssh->version == 2) {
3810 ssh2_add_channel_data(c, sentreply, replylen);
3813 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
3814 PKT_INT, c->remoteid,
3816 PKT_DATA, sentreply, replylen,
3822 * If we've already seen an incoming EOF but haven't sent an
3823 * outgoing one, this may be the moment to send it.
3825 if (c->u.a.outstanding_requests == 0 && (c->closes & CLOSES_RCVD_EOF))
3826 sshfwd_write_eof(c);
3830 * Client-initiated disconnection. Send a DISCONNECT if `wire_reason'
3831 * non-NULL, otherwise just close the connection. `client_reason' == NULL
3832 * => log `wire_reason'.
3834 static void ssh_disconnect(Ssh ssh, const char *client_reason,
3835 const char *wire_reason,
3836 int code, int clean_exit)
3840 client_reason = wire_reason;
3842 error = dupprintf("Disconnected: %s", client_reason);
3844 error = dupstr("Disconnected");
3846 if (ssh->version == 1) {
3847 send_packet(ssh, SSH1_MSG_DISCONNECT, PKT_STR, wire_reason,
3849 } else if (ssh->version == 2) {
3850 struct Packet *pktout = ssh2_pkt_init(SSH2_MSG_DISCONNECT);
3851 ssh2_pkt_adduint32(pktout, code);
3852 ssh2_pkt_addstring(pktout, wire_reason);
3853 ssh2_pkt_addstring(pktout, "en"); /* language tag */
3854 ssh2_pkt_send_noqueue(ssh, pktout);
3857 ssh->close_expected = TRUE;
3858 ssh->clean_exit = clean_exit;
3859 ssh_closing((Plug)ssh, error, 0, 0);
3863 int verify_ssh_manual_host_key(Ssh ssh, const char *fingerprint,
3864 const struct ssh_signkey *ssh2keytype,
3867 if (!conf_get_str_nthstrkey(ssh->conf, CONF_ssh_manual_hostkeys, 0)) {
3868 return -1; /* no manual keys configured */
3873 * The fingerprint string we've been given will have things
3874 * like 'ssh-rsa 2048' at the front of it. Strip those off and
3875 * narrow down to just the colon-separated hex block at the
3876 * end of the string.
3878 const char *p = strrchr(fingerprint, ' ');
3879 fingerprint = p ? p+1 : fingerprint;
3880 /* Quick sanity checks, including making sure it's in lowercase */
3881 assert(strlen(fingerprint) == 16*3 - 1);
3882 assert(fingerprint[2] == ':');
3883 assert(fingerprint[strspn(fingerprint, "0123456789abcdef:")] == 0);
3885 if (conf_get_str_str_opt(ssh->conf, CONF_ssh_manual_hostkeys,
3887 return 1; /* success */
3892 * Construct the base64-encoded public key blob and see if
3895 unsigned char *binblob;
3897 int binlen, atoms, i;
3898 binblob = ssh2keytype->public_blob(ssh2keydata, &binlen);
3899 atoms = (binlen + 2) / 3;
3900 base64blob = snewn(atoms * 4 + 1, char);
3901 for (i = 0; i < atoms; i++)
3902 base64_encode_atom(binblob + 3*i, binlen - 3*i, base64blob + 4*i);
3903 base64blob[atoms * 4] = '\0';
3905 if (conf_get_str_str_opt(ssh->conf, CONF_ssh_manual_hostkeys,
3908 return 1; /* success */
3917 * Handle the key exchange and user authentication phases.
3919 static int do_ssh1_login(Ssh ssh, const unsigned char *in, int inlen,
3920 struct Packet *pktin)
3923 unsigned char cookie[8], *ptr;
3924 struct MD5Context md5c;
3925 struct do_ssh1_login_state {
3928 unsigned char *rsabuf;
3929 const unsigned char *keystr1, *keystr2;
3930 unsigned long supported_ciphers_mask, supported_auths_mask;
3931 int tried_publickey, tried_agent;
3932 int tis_auth_refused, ccard_auth_refused;
3933 unsigned char session_id[16];
3935 void *publickey_blob;
3936 int publickey_bloblen;
3937 char *publickey_comment;
3938 int privatekey_available, privatekey_encrypted;
3939 prompts_t *cur_prompt;
3942 unsigned char request[5], *response, *p;
3952 struct RSAKey servkey, hostkey;
3954 crState(do_ssh1_login_state);
3961 if (pktin->type != SSH1_SMSG_PUBLIC_KEY) {
3962 bombout(("Public key packet not received"));
3966 logevent("Received public keys");
3968 ptr = ssh_pkt_getdata(pktin, 8);
3970 bombout(("SSH-1 public key packet stopped before random cookie"));
3973 memcpy(cookie, ptr, 8);
3975 if (!ssh1_pkt_getrsakey(pktin, &s->servkey, &s->keystr1) ||
3976 !ssh1_pkt_getrsakey(pktin, &s->hostkey, &s->keystr2)) {
3977 bombout(("Failed to read SSH-1 public keys from public key packet"));
3982 * Log the host key fingerprint.
3986 logevent("Host key fingerprint is:");
3987 strcpy(logmsg, " ");
3988 s->hostkey.comment = NULL;
3989 rsa_fingerprint(logmsg + strlen(logmsg),
3990 sizeof(logmsg) - strlen(logmsg), &s->hostkey);
3994 ssh->v1_remote_protoflags = ssh_pkt_getuint32(pktin);
3995 s->supported_ciphers_mask = ssh_pkt_getuint32(pktin);
3996 s->supported_auths_mask = ssh_pkt_getuint32(pktin);
3997 if ((ssh->remote_bugs & BUG_CHOKES_ON_RSA))
3998 s->supported_auths_mask &= ~(1 << SSH1_AUTH_RSA);
4000 ssh->v1_local_protoflags =
4001 ssh->v1_remote_protoflags & SSH1_PROTOFLAGS_SUPPORTED;
4002 ssh->v1_local_protoflags |= SSH1_PROTOFLAG_SCREEN_NUMBER;
4005 MD5Update(&md5c, s->keystr2, s->hostkey.bytes);
4006 MD5Update(&md5c, s->keystr1, s->servkey.bytes);
4007 MD5Update(&md5c, cookie, 8);
4008 MD5Final(s->session_id, &md5c);
4010 for (i = 0; i < 32; i++)
4011 ssh->session_key[i] = random_byte();
4014 * Verify that the `bits' and `bytes' parameters match.
4016 if (s->hostkey.bits > s->hostkey.bytes * 8 ||
4017 s->servkey.bits > s->servkey.bytes * 8) {
4018 bombout(("SSH-1 public keys were badly formatted"));
4022 s->len = (s->hostkey.bytes > s->servkey.bytes ?
4023 s->hostkey.bytes : s->servkey.bytes);
4025 s->rsabuf = snewn(s->len, unsigned char);
4028 * Verify the host key.
4032 * First format the key into a string.
4034 int len = rsastr_len(&s->hostkey);
4035 char fingerprint[100];
4036 char *keystr = snewn(len, char);
4037 rsastr_fmt(keystr, &s->hostkey);
4038 rsa_fingerprint(fingerprint, sizeof(fingerprint), &s->hostkey);
4040 /* First check against manually configured host keys. */
4041 s->dlgret = verify_ssh_manual_host_key(ssh, fingerprint, NULL, NULL);
4042 if (s->dlgret == 0) { /* did not match */
4043 bombout(("Host key did not appear in manually configured list"));
4046 } else if (s->dlgret < 0) { /* none configured; use standard handling */
4047 ssh_set_frozen(ssh, 1);
4048 s->dlgret = verify_ssh_host_key(ssh->frontend,
4049 ssh->savedhost, ssh->savedport,
4050 "rsa", keystr, fingerprint,
4051 ssh_dialog_callback, ssh);
4053 if (s->dlgret < 0) {
4057 bombout(("Unexpected data from server while waiting"
4058 " for user host key response"));
4061 } while (pktin || inlen > 0);
4062 s->dlgret = ssh->user_response;
4064 ssh_set_frozen(ssh, 0);
4066 if (s->dlgret == 0) {
4067 ssh_disconnect(ssh, "User aborted at host key verification",
4076 for (i = 0; i < 32; i++) {
4077 s->rsabuf[i] = ssh->session_key[i];
4079 s->rsabuf[i] ^= s->session_id[i];
4082 if (s->hostkey.bytes > s->servkey.bytes) {
4083 ret = rsaencrypt(s->rsabuf, 32, &s->servkey);
4085 ret = rsaencrypt(s->rsabuf, s->servkey.bytes, &s->hostkey);
4087 ret = rsaencrypt(s->rsabuf, 32, &s->hostkey);
4089 ret = rsaencrypt(s->rsabuf, s->hostkey.bytes, &s->servkey);
4092 bombout(("SSH-1 public key encryptions failed due to bad formatting"));
4096 logevent("Encrypted session key");
4099 int cipher_chosen = 0, warn = 0;
4100 const char *cipher_string = NULL;
4102 for (i = 0; !cipher_chosen && i < CIPHER_MAX; i++) {
4103 int next_cipher = conf_get_int_int(ssh->conf,
4104 CONF_ssh_cipherlist, i);
4105 if (next_cipher == CIPHER_WARN) {
4106 /* If/when we choose a cipher, warn about it */
4108 } else if (next_cipher == CIPHER_AES) {
4109 /* XXX Probably don't need to mention this. */
4110 logevent("AES not supported in SSH-1, skipping");
4112 switch (next_cipher) {
4113 case CIPHER_3DES: s->cipher_type = SSH_CIPHER_3DES;
4114 cipher_string = "3DES"; break;
4115 case CIPHER_BLOWFISH: s->cipher_type = SSH_CIPHER_BLOWFISH;
4116 cipher_string = "Blowfish"; break;
4117 case CIPHER_DES: s->cipher_type = SSH_CIPHER_DES;
4118 cipher_string = "single-DES"; break;
4120 if (s->supported_ciphers_mask & (1 << s->cipher_type))
4124 if (!cipher_chosen) {
4125 if ((s->supported_ciphers_mask & (1 << SSH_CIPHER_3DES)) == 0)
4126 bombout(("Server violates SSH-1 protocol by not "
4127 "supporting 3DES encryption"));
4129 /* shouldn't happen */
4130 bombout(("No supported ciphers found"));
4134 /* Warn about chosen cipher if necessary. */
4136 ssh_set_frozen(ssh, 1);
4137 s->dlgret = askalg(ssh->frontend, "cipher", cipher_string,
4138 ssh_dialog_callback, ssh);
4139 if (s->dlgret < 0) {
4143 bombout(("Unexpected data from server while waiting"
4144 " for user response"));
4147 } while (pktin || inlen > 0);
4148 s->dlgret = ssh->user_response;
4150 ssh_set_frozen(ssh, 0);
4151 if (s->dlgret == 0) {
4152 ssh_disconnect(ssh, "User aborted at cipher warning", NULL,
4159 switch (s->cipher_type) {
4160 case SSH_CIPHER_3DES:
4161 logevent("Using 3DES encryption");
4163 case SSH_CIPHER_DES:
4164 logevent("Using single-DES encryption");
4166 case SSH_CIPHER_BLOWFISH:
4167 logevent("Using Blowfish encryption");
4171 send_packet(ssh, SSH1_CMSG_SESSION_KEY,
4172 PKT_CHAR, s->cipher_type,
4173 PKT_DATA, cookie, 8,
4174 PKT_CHAR, (s->len * 8) >> 8, PKT_CHAR, (s->len * 8) & 0xFF,
4175 PKT_DATA, s->rsabuf, s->len,
4176 PKT_INT, ssh->v1_local_protoflags, PKT_END);
4178 logevent("Trying to enable encryption...");
4182 ssh->cipher = (s->cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 :
4183 s->cipher_type == SSH_CIPHER_DES ? &ssh_des :
4185 ssh->v1_cipher_ctx = ssh->cipher->make_context();
4186 ssh->cipher->sesskey(ssh->v1_cipher_ctx, ssh->session_key);
4187 logeventf(ssh, "Initialised %s encryption", ssh->cipher->text_name);
4189 ssh->crcda_ctx = crcda_make_context();
4190 logevent("Installing CRC compensation attack detector");
4192 if (s->servkey.modulus) {
4193 sfree(s->servkey.modulus);
4194 s->servkey.modulus = NULL;
4196 if (s->servkey.exponent) {
4197 sfree(s->servkey.exponent);
4198 s->servkey.exponent = NULL;
4200 if (s->hostkey.modulus) {
4201 sfree(s->hostkey.modulus);
4202 s->hostkey.modulus = NULL;
4204 if (s->hostkey.exponent) {
4205 sfree(s->hostkey.exponent);
4206 s->hostkey.exponent = NULL;
4210 if (pktin->type != SSH1_SMSG_SUCCESS) {
4211 bombout(("Encryption not successfully enabled"));
4215 logevent("Successfully started encryption");
4217 fflush(stdout); /* FIXME eh? */
4219 if ((ssh->username = get_remote_username(ssh->conf)) == NULL) {
4220 int ret; /* need not be kept over crReturn */
4221 s->cur_prompt = new_prompts(ssh->frontend);
4222 s->cur_prompt->to_server = TRUE;
4223 s->cur_prompt->name = dupstr("SSH login name");
4224 add_prompt(s->cur_prompt, dupstr("login as: "), TRUE);
4225 ret = get_userpass_input(s->cur_prompt, NULL, 0);
4228 crWaitUntil(!pktin);
4229 ret = get_userpass_input(s->cur_prompt, in, inlen);
4234 * Failed to get a username. Terminate.
4236 free_prompts(s->cur_prompt);
4237 ssh_disconnect(ssh, "No username provided", NULL, 0, TRUE);
4240 ssh->username = dupstr(s->cur_prompt->prompts[0]->result);
4241 free_prompts(s->cur_prompt);
4244 send_packet(ssh, SSH1_CMSG_USER, PKT_STR, ssh->username, PKT_END);
4246 char *userlog = dupprintf("Sent username \"%s\"", ssh->username);
4248 if (flags & FLAG_INTERACTIVE &&
4249 (!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) {
4250 c_write_str(ssh, userlog);
4251 c_write_str(ssh, "\r\n");
4259 if ((s->supported_auths_mask & (1 << SSH1_AUTH_RSA)) == 0) {
4260 /* We must not attempt PK auth. Pretend we've already tried it. */
4261 s->tried_publickey = s->tried_agent = 1;
4263 s->tried_publickey = s->tried_agent = 0;
4265 s->tis_auth_refused = s->ccard_auth_refused = 0;
4267 * Load the public half of any configured keyfile for later use.
4269 s->keyfile = conf_get_filename(ssh->conf, CONF_keyfile);
4270 if (!filename_is_null(s->keyfile)) {
4272 logeventf(ssh, "Reading key file \"%.150s\"",
4273 filename_to_str(s->keyfile));
4274 keytype = key_type(s->keyfile);
4275 if (keytype == SSH_KEYTYPE_SSH1 ||
4276 keytype == SSH_KEYTYPE_SSH1_PUBLIC) {
4278 if (rsakey_pubblob(s->keyfile,
4279 &s->publickey_blob, &s->publickey_bloblen,
4280 &s->publickey_comment, &error)) {
4281 s->privatekey_available = (keytype == SSH_KEYTYPE_SSH1);
4282 if (!s->privatekey_available)
4283 logeventf(ssh, "Key file contains public key only");
4284 s->privatekey_encrypted = rsakey_encrypted(s->keyfile,
4288 logeventf(ssh, "Unable to load key (%s)", error);
4289 msgbuf = dupprintf("Unable to load key file "
4290 "\"%.150s\" (%s)\r\n",
4291 filename_to_str(s->keyfile),
4293 c_write_str(ssh, msgbuf);
4295 s->publickey_blob = NULL;
4299 logeventf(ssh, "Unable to use this key file (%s)",
4300 key_type_to_str(keytype));
4301 msgbuf = dupprintf("Unable to use key file \"%.150s\""
4303 filename_to_str(s->keyfile),
4304 key_type_to_str(keytype));
4305 c_write_str(ssh, msgbuf);
4307 s->publickey_blob = NULL;
4310 s->publickey_blob = NULL;
4312 while (pktin->type == SSH1_SMSG_FAILURE) {
4313 s->pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
4315 if (conf_get_int(ssh->conf, CONF_tryagent) && agent_exists() && !s->tried_agent) {
4317 * Attempt RSA authentication using Pageant.
4323 logevent("Pageant is running. Requesting keys.");
4325 /* Request the keys held by the agent. */
4326 PUT_32BIT(s->request, 1);
4327 s->request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES;
4328 if (!agent_query(s->request, 5, &r, &s->responselen,
4329 ssh_agent_callback, ssh)) {
4333 bombout(("Unexpected data from server while waiting"
4334 " for agent response"));
4337 } while (pktin || inlen > 0);
4338 r = ssh->agent_response;
4339 s->responselen = ssh->agent_response_len;
4341 s->response = (unsigned char *) r;
4342 if (s->response && s->responselen >= 5 &&
4343 s->response[4] == SSH1_AGENT_RSA_IDENTITIES_ANSWER) {
4344 s->p = s->response + 5;
4345 s->nkeys = toint(GET_32BIT(s->p));
4347 logeventf(ssh, "Pageant reported negative key count %d",
4352 logeventf(ssh, "Pageant has %d SSH-1 keys", s->nkeys);
4353 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
4354 unsigned char *pkblob = s->p;
4358 do { /* do while (0) to make breaking easy */
4359 n = ssh1_read_bignum
4360 (s->p, toint(s->responselen-(s->p-s->response)),
4365 n = ssh1_read_bignum
4366 (s->p, toint(s->responselen-(s->p-s->response)),
4371 if (s->responselen - (s->p-s->response) < 4)
4373 s->commentlen = toint(GET_32BIT(s->p));
4375 if (s->commentlen < 0 ||
4376 toint(s->responselen - (s->p-s->response)) <
4379 s->commentp = (char *)s->p;
4380 s->p += s->commentlen;
4384 logevent("Pageant key list packet was truncated");
4388 if (s->publickey_blob) {
4389 if (!memcmp(pkblob, s->publickey_blob,
4390 s->publickey_bloblen)) {
4391 logeventf(ssh, "Pageant key #%d matches "
4392 "configured key file", s->keyi);
4393 s->tried_publickey = 1;
4395 /* Skip non-configured key */
4398 logeventf(ssh, "Trying Pageant key #%d", s->keyi);
4399 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
4400 PKT_BIGNUM, s->key.modulus, PKT_END);
4402 if (pktin->type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
4403 logevent("Key refused");
4406 logevent("Received RSA challenge");
4407 if ((s->challenge = ssh1_pkt_getmp(pktin)) == NULL) {
4408 bombout(("Server's RSA challenge was badly formatted"));
4413 char *agentreq, *q, *ret;
4416 len = 1 + 4; /* message type, bit count */
4417 len += ssh1_bignum_length(s->key.exponent);
4418 len += ssh1_bignum_length(s->key.modulus);
4419 len += ssh1_bignum_length(s->challenge);
4420 len += 16; /* session id */
4421 len += 4; /* response format */
4422 agentreq = snewn(4 + len, char);
4423 PUT_32BIT(agentreq, len);
4425 *q++ = SSH1_AGENTC_RSA_CHALLENGE;
4426 PUT_32BIT(q, bignum_bitcount(s->key.modulus));
4428 q += ssh1_write_bignum(q, s->key.exponent);
4429 q += ssh1_write_bignum(q, s->key.modulus);
4430 q += ssh1_write_bignum(q, s->challenge);
4431 memcpy(q, s->session_id, 16);
4433 PUT_32BIT(q, 1); /* response format */
4434 if (!agent_query(agentreq, len + 4, &vret, &retlen,
4435 ssh_agent_callback, ssh)) {
4440 bombout(("Unexpected data from server"
4441 " while waiting for agent"
4445 } while (pktin || inlen > 0);
4446 vret = ssh->agent_response;
4447 retlen = ssh->agent_response_len;
4452 if (ret[4] == SSH1_AGENT_RSA_RESPONSE) {
4453 logevent("Sending Pageant's response");
4454 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
4455 PKT_DATA, ret + 5, 16,
4459 if (pktin->type == SSH1_SMSG_SUCCESS) {
4461 ("Pageant's response accepted");
4462 if (flags & FLAG_VERBOSE) {
4463 c_write_str(ssh, "Authenticated using"
4465 c_write(ssh, s->commentp,
4467 c_write_str(ssh, "\" from agent\r\n");
4472 ("Pageant's response not accepted");
4475 ("Pageant failed to answer challenge");
4479 logevent("No reply received from Pageant");
4482 freebn(s->key.exponent);
4483 freebn(s->key.modulus);
4484 freebn(s->challenge);
4489 if (s->publickey_blob && !s->tried_publickey)
4490 logevent("Configured key file not in Pageant");
4492 logevent("Failed to get reply from Pageant");
4497 if (s->publickey_blob && s->privatekey_available &&
4498 !s->tried_publickey) {
4500 * Try public key authentication with the specified
4503 int got_passphrase; /* need not be kept over crReturn */
4504 if (flags & FLAG_VERBOSE)
4505 c_write_str(ssh, "Trying public key authentication.\r\n");
4506 s->keyfile = conf_get_filename(ssh->conf, CONF_keyfile);
4507 logeventf(ssh, "Trying public key \"%s\"",
4508 filename_to_str(s->keyfile));
4509 s->tried_publickey = 1;
4510 got_passphrase = FALSE;
4511 while (!got_passphrase) {
4513 * Get a passphrase, if necessary.
4515 char *passphrase = NULL; /* only written after crReturn */
4517 if (!s->privatekey_encrypted) {
4518 if (flags & FLAG_VERBOSE)
4519 c_write_str(ssh, "No passphrase required.\r\n");
4522 int ret; /* need not be kept over crReturn */
4523 s->cur_prompt = new_prompts(ssh->frontend);
4524 s->cur_prompt->to_server = FALSE;
4525 s->cur_prompt->name = dupstr("SSH key passphrase");
4526 add_prompt(s->cur_prompt,
4527 dupprintf("Passphrase for key \"%.100s\": ",
4528 s->publickey_comment), FALSE);
4529 ret = get_userpass_input(s->cur_prompt, NULL, 0);
4532 crWaitUntil(!pktin);
4533 ret = get_userpass_input(s->cur_prompt, in, inlen);
4537 /* Failed to get a passphrase. Terminate. */
4538 free_prompts(s->cur_prompt);
4539 ssh_disconnect(ssh, NULL, "Unable to authenticate",
4543 passphrase = dupstr(s->cur_prompt->prompts[0]->result);
4544 free_prompts(s->cur_prompt);
4547 * Try decrypting key with passphrase.
4549 s->keyfile = conf_get_filename(ssh->conf, CONF_keyfile);
4550 ret = loadrsakey(s->keyfile, &s->key, passphrase,
4553 smemclr(passphrase, strlen(passphrase));
4557 /* Correct passphrase. */
4558 got_passphrase = TRUE;
4559 } else if (ret == 0) {
4560 c_write_str(ssh, "Couldn't load private key from ");
4561 c_write_str(ssh, filename_to_str(s->keyfile));
4562 c_write_str(ssh, " (");
4563 c_write_str(ssh, error);
4564 c_write_str(ssh, ").\r\n");
4565 got_passphrase = FALSE;
4566 break; /* go and try something else */
4567 } else if (ret == -1) {
4568 c_write_str(ssh, "Wrong passphrase.\r\n"); /* FIXME */
4569 got_passphrase = FALSE;
4572 assert(0 && "unexpected return from loadrsakey()");
4573 got_passphrase = FALSE; /* placate optimisers */
4577 if (got_passphrase) {
4580 * Send a public key attempt.
4582 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
4583 PKT_BIGNUM, s->key.modulus, PKT_END);
4586 if (pktin->type == SSH1_SMSG_FAILURE) {
4587 c_write_str(ssh, "Server refused our public key.\r\n");
4588 continue; /* go and try something else */
4590 if (pktin->type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
4591 bombout(("Bizarre response to offer of public key"));
4597 unsigned char buffer[32];
4598 Bignum challenge, response;
4600 if ((challenge = ssh1_pkt_getmp(pktin)) == NULL) {
4601 bombout(("Server's RSA challenge was badly formatted"));
4604 response = rsadecrypt(challenge, &s->key);
4605 freebn(s->key.private_exponent);/* burn the evidence */
4607 for (i = 0; i < 32; i++) {
4608 buffer[i] = bignum_byte(response, 31 - i);
4612 MD5Update(&md5c, buffer, 32);
4613 MD5Update(&md5c, s->session_id, 16);
4614 MD5Final(buffer, &md5c);
4616 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
4617 PKT_DATA, buffer, 16, PKT_END);
4624 if (pktin->type == SSH1_SMSG_FAILURE) {
4625 if (flags & FLAG_VERBOSE)
4626 c_write_str(ssh, "Failed to authenticate with"
4627 " our public key.\r\n");
4628 continue; /* go and try something else */
4629 } else if (pktin->type != SSH1_SMSG_SUCCESS) {
4630 bombout(("Bizarre response to RSA authentication response"));
4634 break; /* we're through! */
4640 * Otherwise, try various forms of password-like authentication.
4642 s->cur_prompt = new_prompts(ssh->frontend);
4644 if (conf_get_int(ssh->conf, CONF_try_tis_auth) &&
4645 (s->supported_auths_mask & (1 << SSH1_AUTH_TIS)) &&
4646 !s->tis_auth_refused) {
4647 s->pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
4648 logevent("Requested TIS authentication");
4649 send_packet(ssh, SSH1_CMSG_AUTH_TIS, PKT_END);
4651 if (pktin->type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
4652 logevent("TIS authentication declined");
4653 if (flags & FLAG_INTERACTIVE)
4654 c_write_str(ssh, "TIS authentication refused.\r\n");
4655 s->tis_auth_refused = 1;
4660 char *instr_suf, *prompt;
4662 ssh_pkt_getstring(pktin, &challenge, &challengelen);
4664 bombout(("TIS challenge packet was badly formed"));
4667 logevent("Received TIS challenge");
4668 s->cur_prompt->to_server = TRUE;
4669 s->cur_prompt->name = dupstr("SSH TIS authentication");
4670 /* Prompt heuristic comes from OpenSSH */
4671 if (memchr(challenge, '\n', challengelen)) {
4672 instr_suf = dupstr("");
4673 prompt = dupprintf("%.*s", challengelen, challenge);
4675 instr_suf = dupprintf("%.*s", challengelen, challenge);
4676 prompt = dupstr("Response: ");
4678 s->cur_prompt->instruction =
4679 dupprintf("Using TIS authentication.%s%s",
4680 (*instr_suf) ? "\n" : "",
4682 s->cur_prompt->instr_reqd = TRUE;
4683 add_prompt(s->cur_prompt, prompt, FALSE);
4687 if (conf_get_int(ssh->conf, CONF_try_tis_auth) &&
4688 (s->supported_auths_mask & (1 << SSH1_AUTH_CCARD)) &&
4689 !s->ccard_auth_refused) {
4690 s->pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE;
4691 logevent("Requested CryptoCard authentication");
4692 send_packet(ssh, SSH1_CMSG_AUTH_CCARD, PKT_END);
4694 if (pktin->type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
4695 logevent("CryptoCard authentication declined");
4696 c_write_str(ssh, "CryptoCard authentication refused.\r\n");
4697 s->ccard_auth_refused = 1;
4702 char *instr_suf, *prompt;
4704 ssh_pkt_getstring(pktin, &challenge, &challengelen);
4706 bombout(("CryptoCard challenge packet was badly formed"));
4709 logevent("Received CryptoCard challenge");
4710 s->cur_prompt->to_server = TRUE;
4711 s->cur_prompt->name = dupstr("SSH CryptoCard authentication");
4712 s->cur_prompt->name_reqd = FALSE;
4713 /* Prompt heuristic comes from OpenSSH */
4714 if (memchr(challenge, '\n', challengelen)) {
4715 instr_suf = dupstr("");
4716 prompt = dupprintf("%.*s", challengelen, challenge);
4718 instr_suf = dupprintf("%.*s", challengelen, challenge);
4719 prompt = dupstr("Response: ");
4721 s->cur_prompt->instruction =
4722 dupprintf("Using CryptoCard authentication.%s%s",
4723 (*instr_suf) ? "\n" : "",
4725 s->cur_prompt->instr_reqd = TRUE;
4726 add_prompt(s->cur_prompt, prompt, FALSE);
4730 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
4731 if ((s->supported_auths_mask & (1 << SSH1_AUTH_PASSWORD)) == 0) {
4732 bombout(("No supported authentication methods available"));
4735 s->cur_prompt->to_server = TRUE;
4736 s->cur_prompt->name = dupstr("SSH password");
4737 add_prompt(s->cur_prompt, dupprintf("%s@%s's password: ",
4738 ssh->username, ssh->savedhost),
4743 * Show password prompt, having first obtained it via a TIS
4744 * or CryptoCard exchange if we're doing TIS or CryptoCard
4748 int ret; /* need not be kept over crReturn */
4749 ret = get_userpass_input(s->cur_prompt, NULL, 0);
4752 crWaitUntil(!pktin);
4753 ret = get_userpass_input(s->cur_prompt, in, inlen);
4758 * Failed to get a password (for example
4759 * because one was supplied on the command line
4760 * which has already failed to work). Terminate.
4762 free_prompts(s->cur_prompt);
4763 ssh_disconnect(ssh, NULL, "Unable to authenticate", 0, TRUE);
4768 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
4770 * Defence against traffic analysis: we send a
4771 * whole bunch of packets containing strings of
4772 * different lengths. One of these strings is the
4773 * password, in a SSH1_CMSG_AUTH_PASSWORD packet.
4774 * The others are all random data in
4775 * SSH1_MSG_IGNORE packets. This way a passive
4776 * listener can't tell which is the password, and
4777 * hence can't deduce the password length.
4779 * Anybody with a password length greater than 16
4780 * bytes is going to have enough entropy in their
4781 * password that a listener won't find it _that_
4782 * much help to know how long it is. So what we'll
4785 * - if password length < 16, we send 15 packets
4786 * containing string lengths 1 through 15
4788 * - otherwise, we let N be the nearest multiple
4789 * of 8 below the password length, and send 8
4790 * packets containing string lengths N through
4791 * N+7. This won't obscure the order of
4792 * magnitude of the password length, but it will
4793 * introduce a bit of extra uncertainty.
4795 * A few servers can't deal with SSH1_MSG_IGNORE, at
4796 * least in this context. For these servers, we need
4797 * an alternative defence. We make use of the fact
4798 * that the password is interpreted as a C string:
4799 * so we can append a NUL, then some random data.
4801 * A few servers can deal with neither SSH1_MSG_IGNORE
4802 * here _nor_ a padded password string.
4803 * For these servers we are left with no defences
4804 * against password length sniffing.
4806 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE) &&
4807 !(ssh->remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) {
4809 * The server can deal with SSH1_MSG_IGNORE, so
4810 * we can use the primary defence.
4812 int bottom, top, pwlen, i;
4815 pwlen = strlen(s->cur_prompt->prompts[0]->result);
4817 bottom = 0; /* zero length passwords are OK! :-) */
4820 bottom = pwlen & ~7;
4824 assert(pwlen >= bottom && pwlen <= top);
4826 randomstr = snewn(top + 1, char);
4828 for (i = bottom; i <= top; i++) {
4830 defer_packet(ssh, s->pwpkt_type,
4831 PKT_STR,s->cur_prompt->prompts[0]->result,
4834 for (j = 0; j < i; j++) {
4836 randomstr[j] = random_byte();
4837 } while (randomstr[j] == '\0');
4839 randomstr[i] = '\0';
4840 defer_packet(ssh, SSH1_MSG_IGNORE,
4841 PKT_STR, randomstr, PKT_END);
4844 logevent("Sending password with camouflage packets");
4845 ssh_pkt_defersend(ssh);
4848 else if (!(ssh->remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) {
4850 * The server can't deal with SSH1_MSG_IGNORE
4851 * but can deal with padded passwords, so we
4852 * can use the secondary defence.
4858 len = strlen(s->cur_prompt->prompts[0]->result);
4859 if (len < sizeof(string)) {
4861 strcpy(string, s->cur_prompt->prompts[0]->result);
4862 len++; /* cover the zero byte */
4863 while (len < sizeof(string)) {
4864 string[len++] = (char) random_byte();
4867 ss = s->cur_prompt->prompts[0]->result;
4869 logevent("Sending length-padded password");
4870 send_packet(ssh, s->pwpkt_type,
4871 PKT_INT, len, PKT_DATA, ss, len,
4875 * The server is believed unable to cope with
4876 * any of our password camouflage methods.
4879 len = strlen(s->cur_prompt->prompts[0]->result);
4880 logevent("Sending unpadded password");
4881 send_packet(ssh, s->pwpkt_type,
4883 PKT_DATA, s->cur_prompt->prompts[0]->result, len,
4887 send_packet(ssh, s->pwpkt_type,
4888 PKT_STR, s->cur_prompt->prompts[0]->result,
4891 logevent("Sent password");
4892 free_prompts(s->cur_prompt);
4894 if (pktin->type == SSH1_SMSG_FAILURE) {
4895 if (flags & FLAG_VERBOSE)
4896 c_write_str(ssh, "Access denied\r\n");
4897 logevent("Authentication refused");
4898 } else if (pktin->type != SSH1_SMSG_SUCCESS) {
4899 bombout(("Strange packet received, type %d", pktin->type));
4905 if (s->publickey_blob) {
4906 sfree(s->publickey_blob);
4907 sfree(s->publickey_comment);
4910 logevent("Authentication successful");
4915 static void ssh_channel_try_eof(struct ssh_channel *c)
4918 assert(c->pending_eof); /* precondition for calling us */
4920 return; /* can't close: not even opened yet */
4921 if (ssh->version == 2 && bufchain_size(&c->v.v2.outbuffer) > 0)
4922 return; /* can't send EOF: pending outgoing data */
4924 c->pending_eof = FALSE; /* we're about to send it */
4925 if (ssh->version == 1) {
4926 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid,
4928 c->closes |= CLOSES_SENT_EOF;
4930 struct Packet *pktout;
4931 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_EOF);
4932 ssh2_pkt_adduint32(pktout, c->remoteid);
4933 ssh2_pkt_send(ssh, pktout);
4934 c->closes |= CLOSES_SENT_EOF;
4935 ssh2_channel_check_close(c);
4939 Conf *sshfwd_get_conf(struct ssh_channel *c)
4945 void sshfwd_write_eof(struct ssh_channel *c)
4949 if (ssh->state == SSH_STATE_CLOSED)
4952 if (c->closes & CLOSES_SENT_EOF)
4955 c->pending_eof = TRUE;
4956 ssh_channel_try_eof(c);
4959 void sshfwd_unclean_close(struct ssh_channel *c, const char *err)
4963 if (ssh->state == SSH_STATE_CLOSED)
4968 x11_close(c->u.x11.xconn);
4969 logeventf(ssh, "Forwarded X11 connection terminated due to local "
4973 case CHAN_SOCKDATA_DORMANT:
4974 pfd_close(c->u.pfd.pf);
4975 logeventf(ssh, "Forwarded port closed due to local error: %s", err);
4978 c->type = CHAN_ZOMBIE;
4979 c->pending_eof = FALSE; /* this will confuse a zombie channel */
4981 ssh2_channel_check_close(c);
4984 int sshfwd_write(struct ssh_channel *c, char *buf, int len)
4988 if (ssh->state == SSH_STATE_CLOSED)
4991 if (ssh->version == 1) {
4992 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
4993 PKT_INT, c->remoteid,
4994 PKT_INT, len, PKT_DATA, buf, len,
4997 * In SSH-1 we can return 0 here - implying that forwarded
4998 * connections are never individually throttled - because
4999 * the only circumstance that can cause throttling will be
5000 * the whole SSH connection backing up, in which case
5001 * _everything_ will be throttled as a whole.
5005 ssh2_add_channel_data(c, buf, len);
5006 return ssh2_try_send(c);
5010 void sshfwd_unthrottle(struct ssh_channel *c, int bufsize)
5015 if (ssh->state == SSH_STATE_CLOSED)
5018 if (ssh->version == 1) {
5019 buflimit = SSH1_BUFFER_LIMIT;
5021 buflimit = c->v.v2.locmaxwin;
5022 ssh2_set_window(c, bufsize < buflimit ? buflimit - bufsize : 0);
5024 if (c->throttling_conn && bufsize <= buflimit) {
5025 c->throttling_conn = 0;
5026 ssh_throttle_conn(ssh, -1);
5030 static void ssh_queueing_handler(Ssh ssh, struct Packet *pktin)
5032 struct queued_handler *qh = ssh->qhead;
5036 assert(pktin->type == qh->msg1 || pktin->type == qh->msg2);
5039 assert(ssh->packet_dispatch[qh->msg1] == ssh_queueing_handler);
5040 ssh->packet_dispatch[qh->msg1] = ssh->q_saved_handler1;
5043 assert(ssh->packet_dispatch[qh->msg2] == ssh_queueing_handler);
5044 ssh->packet_dispatch[qh->msg2] = ssh->q_saved_handler2;
5048 ssh->qhead = qh->next;
5050 if (ssh->qhead->msg1 > 0) {
5051 ssh->q_saved_handler1 = ssh->packet_dispatch[ssh->qhead->msg1];
5052 ssh->packet_dispatch[ssh->qhead->msg1] = ssh_queueing_handler;
5054 if (ssh->qhead->msg2 > 0) {
5055 ssh->q_saved_handler2 = ssh->packet_dispatch[ssh->qhead->msg2];
5056 ssh->packet_dispatch[ssh->qhead->msg2] = ssh_queueing_handler;
5059 ssh->qhead = ssh->qtail = NULL;
5062 qh->handler(ssh, pktin, qh->ctx);
5067 static void ssh_queue_handler(Ssh ssh, int msg1, int msg2,
5068 chandler_fn_t handler, void *ctx)
5070 struct queued_handler *qh;
5072 qh = snew(struct queued_handler);
5075 qh->handler = handler;
5079 if (ssh->qtail == NULL) {
5083 ssh->q_saved_handler1 = ssh->packet_dispatch[ssh->qhead->msg1];
5084 ssh->packet_dispatch[qh->msg1] = ssh_queueing_handler;
5087 ssh->q_saved_handler2 = ssh->packet_dispatch[ssh->qhead->msg2];
5088 ssh->packet_dispatch[qh->msg2] = ssh_queueing_handler;
5091 ssh->qtail->next = qh;
5096 static void ssh_rportfwd_succfail(Ssh ssh, struct Packet *pktin, void *ctx)
5098 struct ssh_rportfwd *rpf, *pf = (struct ssh_rportfwd *)ctx;
5100 if (pktin->type == (ssh->version == 1 ? SSH1_SMSG_SUCCESS :
5101 SSH2_MSG_REQUEST_SUCCESS)) {
5102 logeventf(ssh, "Remote port forwarding from %s enabled",
5105 logeventf(ssh, "Remote port forwarding from %s refused",
5108 rpf = del234(ssh->rportfwds, pf);
5110 pf->pfrec->remote = NULL;
5115 int ssh_alloc_sharing_rportfwd(Ssh ssh, const char *shost, int sport,
5118 struct ssh_rportfwd *pf = snew(struct ssh_rportfwd);
5121 pf->share_ctx = share_ctx;
5122 pf->shost = dupstr(shost);
5124 pf->sportdesc = NULL;
5125 if (!ssh->rportfwds) {
5126 assert(ssh->version == 2);
5127 ssh->rportfwds = newtree234(ssh_rportcmp_ssh2);
5129 if (add234(ssh->rportfwds, pf) != pf) {
5137 static void ssh_sharing_global_request_response(Ssh ssh, struct Packet *pktin,
5140 share_got_pkt_from_server(ctx, pktin->type,
5141 pktin->body, pktin->length);
5144 void ssh_sharing_queue_global_request(Ssh ssh, void *share_ctx)
5146 ssh_queue_handler(ssh, SSH2_MSG_REQUEST_SUCCESS, SSH2_MSG_REQUEST_FAILURE,
5147 ssh_sharing_global_request_response, share_ctx);
5150 static void ssh_setup_portfwd(Ssh ssh, Conf *conf)
5152 struct ssh_portfwd *epf;
5156 if (!ssh->portfwds) {
5157 ssh->portfwds = newtree234(ssh_portcmp);
5160 * Go through the existing port forwardings and tag them
5161 * with status==DESTROY. Any that we want to keep will be
5162 * re-enabled (status==KEEP) as we go through the
5163 * configuration and find out which bits are the same as
5166 struct ssh_portfwd *epf;
5168 for (i = 0; (epf = index234(ssh->portfwds, i)) != NULL; i++)
5169 epf->status = DESTROY;
5172 for (val = conf_get_str_strs(conf, CONF_portfwd, NULL, &key);
5174 val = conf_get_str_strs(conf, CONF_portfwd, key, &key)) {
5175 char *kp, *kp2, *vp, *vp2;
5176 char address_family, type;
5177 int sport,dport,sserv,dserv;
5178 char *sports, *dports, *saddr, *host;
5182 address_family = 'A';
5184 if (*kp == 'A' || *kp == '4' || *kp == '6')
5185 address_family = *kp++;
5186 if (*kp == 'L' || *kp == 'R')
5189 if ((kp2 = host_strchr(kp, ':')) != NULL) {
5191 * There's a colon in the middle of the source port
5192 * string, which means that the part before it is
5193 * actually a source address.
5195 char *saddr_tmp = dupprintf("%.*s", (int)(kp2 - kp), kp);
5196 saddr = host_strduptrim(saddr_tmp);
5203 sport = atoi(sports);
5207 sport = net_service_lookup(sports);
5209 logeventf(ssh, "Service lookup failed for source"
5210 " port \"%s\"", sports);
5214 if (type == 'L' && !strcmp(val, "D")) {
5215 /* dynamic forwarding */
5222 /* ordinary forwarding */
5224 vp2 = vp + host_strcspn(vp, ":");
5225 host = dupprintf("%.*s", (int)(vp2 - vp), vp);
5229 dport = atoi(dports);
5233 dport = net_service_lookup(dports);
5235 logeventf(ssh, "Service lookup failed for destination"
5236 " port \"%s\"", dports);
5241 if (sport && dport) {
5242 /* Set up a description of the source port. */
5243 struct ssh_portfwd *pfrec, *epfrec;
5245 pfrec = snew(struct ssh_portfwd);
5247 pfrec->saddr = saddr;
5248 pfrec->sserv = sserv ? dupstr(sports) : NULL;
5249 pfrec->sport = sport;
5250 pfrec->daddr = host;
5251 pfrec->dserv = dserv ? dupstr(dports) : NULL;
5252 pfrec->dport = dport;
5253 pfrec->local = NULL;
5254 pfrec->remote = NULL;
5255 pfrec->addressfamily = (address_family == '4' ? ADDRTYPE_IPV4 :
5256 address_family == '6' ? ADDRTYPE_IPV6 :
5259 epfrec = add234(ssh->portfwds, pfrec);
5260 if (epfrec != pfrec) {
5261 if (epfrec->status == DESTROY) {
5263 * We already have a port forwarding up and running
5264 * with precisely these parameters. Hence, no need
5265 * to do anything; simply re-tag the existing one
5268 epfrec->status = KEEP;
5271 * Anything else indicates that there was a duplicate
5272 * in our input, which we'll silently ignore.
5274 free_portfwd(pfrec);
5276 pfrec->status = CREATE;
5285 * Now go through and destroy any port forwardings which were
5288 for (i = 0; (epf = index234(ssh->portfwds, i)) != NULL; i++)
5289 if (epf->status == DESTROY) {
5292 message = dupprintf("%s port forwarding from %s%s%d",
5293 epf->type == 'L' ? "local" :
5294 epf->type == 'R' ? "remote" : "dynamic",
5295 epf->saddr ? epf->saddr : "",
5296 epf->saddr ? ":" : "",
5299 if (epf->type != 'D') {
5300 char *msg2 = dupprintf("%s to %s:%d", message,
5301 epf->daddr, epf->dport);
5306 logeventf(ssh, "Cancelling %s", message);
5309 /* epf->remote or epf->local may be NULL if setting up a
5310 * forwarding failed. */
5312 struct ssh_rportfwd *rpf = epf->remote;
5313 struct Packet *pktout;
5316 * Cancel the port forwarding at the server
5319 if (ssh->version == 1) {
5321 * We cannot cancel listening ports on the
5322 * server side in SSH-1! There's no message
5323 * to support it. Instead, we simply remove
5324 * the rportfwd record from the local end
5325 * so that any connections the server tries
5326 * to make on it are rejected.
5329 pktout = ssh2_pkt_init(SSH2_MSG_GLOBAL_REQUEST);
5330 ssh2_pkt_addstring(pktout, "cancel-tcpip-forward");
5331 ssh2_pkt_addbool(pktout, 0);/* _don't_ want reply */
5333 ssh2_pkt_addstring(pktout, epf->saddr);
5334 } else if (conf_get_int(conf, CONF_rport_acceptall)) {
5335 /* XXX: rport_acceptall may not represent
5336 * what was used to open the original connection,
5337 * since it's reconfigurable. */
5338 ssh2_pkt_addstring(pktout, "");
5340 ssh2_pkt_addstring(pktout, "localhost");
5342 ssh2_pkt_adduint32(pktout, epf->sport);
5343 ssh2_pkt_send(ssh, pktout);
5346 del234(ssh->rportfwds, rpf);
5348 } else if (epf->local) {
5349 pfl_terminate(epf->local);
5352 delpos234(ssh->portfwds, i);
5354 i--; /* so we don't skip one in the list */
5358 * And finally, set up any new port forwardings (status==CREATE).
5360 for (i = 0; (epf = index234(ssh->portfwds, i)) != NULL; i++)
5361 if (epf->status == CREATE) {
5362 char *sportdesc, *dportdesc;
5363 sportdesc = dupprintf("%s%s%s%s%d%s",
5364 epf->saddr ? epf->saddr : "",
5365 epf->saddr ? ":" : "",
5366 epf->sserv ? epf->sserv : "",
5367 epf->sserv ? "(" : "",
5369 epf->sserv ? ")" : "");
5370 if (epf->type == 'D') {
5373 dportdesc = dupprintf("%s:%s%s%d%s",
5375 epf->dserv ? epf->dserv : "",
5376 epf->dserv ? "(" : "",
5378 epf->dserv ? ")" : "");
5381 if (epf->type == 'L') {
5382 char *err = pfl_listen(epf->daddr, epf->dport,
5383 epf->saddr, epf->sport,
5384 ssh, conf, &epf->local,
5385 epf->addressfamily);
5387 logeventf(ssh, "Local %sport %s forwarding to %s%s%s",
5388 epf->addressfamily == ADDRTYPE_IPV4 ? "IPv4 " :
5389 epf->addressfamily == ADDRTYPE_IPV6 ? "IPv6 " : "",
5390 sportdesc, dportdesc,
5391 err ? " failed: " : "", err ? err : "");
5394 } else if (epf->type == 'D') {
5395 char *err = pfl_listen(NULL, -1, epf->saddr, epf->sport,
5396 ssh, conf, &epf->local,
5397 epf->addressfamily);
5399 logeventf(ssh, "Local %sport %s SOCKS dynamic forwarding%s%s",
5400 epf->addressfamily == ADDRTYPE_IPV4 ? "IPv4 " :
5401 epf->addressfamily == ADDRTYPE_IPV6 ? "IPv6 " : "",
5403 err ? " failed: " : "", err ? err : "");
5408 struct ssh_rportfwd *pf;
5411 * Ensure the remote port forwardings tree exists.
5413 if (!ssh->rportfwds) {
5414 if (ssh->version == 1)
5415 ssh->rportfwds = newtree234(ssh_rportcmp_ssh1);
5417 ssh->rportfwds = newtree234(ssh_rportcmp_ssh2);
5420 pf = snew(struct ssh_rportfwd);
5421 pf->share_ctx = NULL;
5422 pf->dhost = dupstr(epf->daddr);
5423 pf->dport = epf->dport;
5425 pf->shost = dupstr(epf->saddr);
5426 } else if (conf_get_int(conf, CONF_rport_acceptall)) {
5427 pf->shost = dupstr("");
5429 pf->shost = dupstr("localhost");
5431 pf->sport = epf->sport;
5432 if (add234(ssh->rportfwds, pf) != pf) {
5433 logeventf(ssh, "Duplicate remote port forwarding to %s:%d",
5434 epf->daddr, epf->dport);
5437 logeventf(ssh, "Requesting remote port %s"
5438 " forward to %s", sportdesc, dportdesc);
5440 pf->sportdesc = sportdesc;
5445 if (ssh->version == 1) {
5446 send_packet(ssh, SSH1_CMSG_PORT_FORWARD_REQUEST,
5447 PKT_INT, epf->sport,
5448 PKT_STR, epf->daddr,
5449 PKT_INT, epf->dport,
5451 ssh_queue_handler(ssh, SSH1_SMSG_SUCCESS,
5453 ssh_rportfwd_succfail, pf);
5455 struct Packet *pktout;
5456 pktout = ssh2_pkt_init(SSH2_MSG_GLOBAL_REQUEST);
5457 ssh2_pkt_addstring(pktout, "tcpip-forward");
5458 ssh2_pkt_addbool(pktout, 1);/* want reply */
5459 ssh2_pkt_addstring(pktout, pf->shost);
5460 ssh2_pkt_adduint32(pktout, pf->sport);
5461 ssh2_pkt_send(ssh, pktout);
5463 ssh_queue_handler(ssh, SSH2_MSG_REQUEST_SUCCESS,
5464 SSH2_MSG_REQUEST_FAILURE,
5465 ssh_rportfwd_succfail, pf);
5474 static void ssh1_smsg_stdout_stderr_data(Ssh ssh, struct Packet *pktin)
5477 int stringlen, bufsize;
5479 ssh_pkt_getstring(pktin, &string, &stringlen);
5480 if (string == NULL) {
5481 bombout(("Incoming terminal data packet was badly formed"));
5485 bufsize = from_backend(ssh->frontend, pktin->type == SSH1_SMSG_STDERR_DATA,
5487 if (!ssh->v1_stdout_throttling && bufsize > SSH1_BUFFER_LIMIT) {
5488 ssh->v1_stdout_throttling = 1;
5489 ssh_throttle_conn(ssh, +1);
5493 static void ssh1_smsg_x11_open(Ssh ssh, struct Packet *pktin)
5495 /* Remote side is trying to open a channel to talk to our
5496 * X-Server. Give them back a local channel number. */
5497 struct ssh_channel *c;
5498 int remoteid = ssh_pkt_getuint32(pktin);
5500 logevent("Received X11 connect request");
5501 /* Refuse if X11 forwarding is disabled. */
5502 if (!ssh->X11_fwd_enabled) {
5503 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
5504 PKT_INT, remoteid, PKT_END);
5505 logevent("Rejected X11 connect request");
5507 c = snew(struct ssh_channel);
5510 c->u.x11.xconn = x11_init(ssh->x11authtree, c, NULL, -1);
5511 c->remoteid = remoteid;
5512 c->halfopen = FALSE;
5513 c->localid = alloc_channel_id(ssh);
5515 c->pending_eof = FALSE;
5516 c->throttling_conn = 0;
5517 c->type = CHAN_X11; /* identify channel type */
5518 add234(ssh->channels, c);
5519 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
5520 PKT_INT, c->remoteid, PKT_INT,
5521 c->localid, PKT_END);
5522 logevent("Opened X11 forward channel");
5526 static void ssh1_smsg_agent_open(Ssh ssh, struct Packet *pktin)
5528 /* Remote side is trying to open a channel to talk to our
5529 * agent. Give them back a local channel number. */
5530 struct ssh_channel *c;
5531 int remoteid = ssh_pkt_getuint32(pktin);
5533 /* Refuse if agent forwarding is disabled. */
5534 if (!ssh->agentfwd_enabled) {
5535 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
5536 PKT_INT, remoteid, PKT_END);
5538 c = snew(struct ssh_channel);
5540 c->remoteid = remoteid;
5541 c->halfopen = FALSE;
5542 c->localid = alloc_channel_id(ssh);
5544 c->pending_eof = FALSE;
5545 c->throttling_conn = 0;
5546 c->type = CHAN_AGENT; /* identify channel type */
5547 c->u.a.lensofar = 0;
5548 c->u.a.message = NULL;
5549 c->u.a.outstanding_requests = 0;
5550 add234(ssh->channels, c);
5551 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
5552 PKT_INT, c->remoteid, PKT_INT, c->localid,
5557 static void ssh1_msg_port_open(Ssh ssh, struct Packet *pktin)
5559 /* Remote side is trying to open a channel to talk to a
5560 * forwarded port. Give them back a local channel number. */
5561 struct ssh_rportfwd pf, *pfp;
5567 remoteid = ssh_pkt_getuint32(pktin);
5568 ssh_pkt_getstring(pktin, &host, &hostsize);
5569 port = ssh_pkt_getuint32(pktin);
5571 pf.dhost = dupprintf("%.*s", hostsize, host);
5573 pfp = find234(ssh->rportfwds, &pf, NULL);
5576 logeventf(ssh, "Rejected remote port open request for %s:%d",
5578 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
5579 PKT_INT, remoteid, PKT_END);
5581 struct ssh_channel *c = snew(struct ssh_channel);
5584 logeventf(ssh, "Received remote port open request for %s:%d",
5586 err = pfd_connect(&c->u.pfd.pf, pf.dhost, port,
5587 c, ssh->conf, pfp->pfrec->addressfamily);
5589 logeventf(ssh, "Port open failed: %s", err);
5592 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
5593 PKT_INT, remoteid, PKT_END);
5595 c->remoteid = remoteid;
5596 c->halfopen = FALSE;
5597 c->localid = alloc_channel_id(ssh);
5599 c->pending_eof = FALSE;
5600 c->throttling_conn = 0;
5601 c->type = CHAN_SOCKDATA; /* identify channel type */
5602 add234(ssh->channels, c);
5603 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
5604 PKT_INT, c->remoteid, PKT_INT,
5605 c->localid, PKT_END);
5606 logevent("Forwarded port opened successfully");
5613 static void ssh1_msg_channel_open_confirmation(Ssh ssh, struct Packet *pktin)
5615 unsigned int remoteid = ssh_pkt_getuint32(pktin);
5616 unsigned int localid = ssh_pkt_getuint32(pktin);
5617 struct ssh_channel *c;
5619 c = find234(ssh->channels, &remoteid, ssh_channelfind);
5620 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
5621 c->remoteid = localid;
5622 c->halfopen = FALSE;
5623 c->type = CHAN_SOCKDATA;
5624 c->throttling_conn = 0;
5625 pfd_confirm(c->u.pfd.pf);
5628 if (c && c->pending_eof) {
5630 * We have a pending close on this channel,
5631 * which we decided on before the server acked
5632 * the channel open. So now we know the
5633 * remoteid, we can close it again.
5635 ssh_channel_try_eof(c);
5639 static void ssh1_msg_channel_open_failure(Ssh ssh, struct Packet *pktin)
5641 unsigned int remoteid = ssh_pkt_getuint32(pktin);
5642 struct ssh_channel *c;
5644 c = find234(ssh->channels, &remoteid, ssh_channelfind);
5645 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
5646 logevent("Forwarded connection refused by server");
5647 pfd_close(c->u.pfd.pf);
5648 del234(ssh->channels, c);
5653 static void ssh1_msg_channel_close(Ssh ssh, struct Packet *pktin)
5655 /* Remote side closes a channel. */
5656 unsigned i = ssh_pkt_getuint32(pktin);
5657 struct ssh_channel *c;
5658 c = find234(ssh->channels, &i, ssh_channelfind);
5659 if (c && !c->halfopen) {
5661 if (pktin->type == SSH1_MSG_CHANNEL_CLOSE &&
5662 !(c->closes & CLOSES_RCVD_EOF)) {
5664 * Received CHANNEL_CLOSE, which we translate into
5667 int send_close = FALSE;
5669 c->closes |= CLOSES_RCVD_EOF;
5674 x11_send_eof(c->u.x11.xconn);
5680 pfd_send_eof(c->u.pfd.pf);
5689 if (send_close && !(c->closes & CLOSES_SENT_EOF)) {
5690 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid,
5692 c->closes |= CLOSES_SENT_EOF;
5696 if (pktin->type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION &&
5697 !(c->closes & CLOSES_RCVD_CLOSE)) {
5699 if (!(c->closes & CLOSES_SENT_EOF)) {
5700 bombout(("Received CHANNEL_CLOSE_CONFIRMATION for channel %d"
5701 " for which we never sent CHANNEL_CLOSE\n", i));
5704 c->closes |= CLOSES_RCVD_CLOSE;
5707 if (!((CLOSES_SENT_EOF | CLOSES_RCVD_EOF) & ~c->closes) &&
5708 !(c->closes & CLOSES_SENT_CLOSE)) {
5709 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION,
5710 PKT_INT, c->remoteid, PKT_END);
5711 c->closes |= CLOSES_SENT_CLOSE;
5714 if (!((CLOSES_SENT_CLOSE | CLOSES_RCVD_CLOSE) & ~c->closes))
5715 ssh_channel_destroy(c);
5717 bombout(("Received CHANNEL_CLOSE%s for %s channel %d\n",
5718 pktin->type == SSH1_MSG_CHANNEL_CLOSE ? "" :
5719 "_CONFIRMATION", c ? "half-open" : "nonexistent",
5724 static void ssh1_msg_channel_data(Ssh ssh, struct Packet *pktin)
5726 /* Data sent down one of our channels. */
5727 int i = ssh_pkt_getuint32(pktin);
5730 struct ssh_channel *c;
5732 ssh_pkt_getstring(pktin, &p, &len);
5734 c = find234(ssh->channels, &i, ssh_channelfind);
5739 bufsize = x11_send(c->u.x11.xconn, p, len);
5742 bufsize = pfd_send(c->u.pfd.pf, p, len);
5745 /* Data for an agent message. Buffer it. */
5747 if (c->u.a.lensofar < 4) {
5748 unsigned int l = min(4 - c->u.a.lensofar, (unsigned)len);
5749 memcpy(c->u.a.msglen + c->u.a.lensofar, p,
5753 c->u.a.lensofar += l;
5755 if (c->u.a.lensofar == 4) {
5757 4 + GET_32BIT(c->u.a.msglen);
5758 c->u.a.message = snewn(c->u.a.totallen,
5760 memcpy(c->u.a.message, c->u.a.msglen, 4);
5762 if (c->u.a.lensofar >= 4 && len > 0) {
5764 min(c->u.a.totallen - c->u.a.lensofar,
5766 memcpy(c->u.a.message + c->u.a.lensofar, p,
5770 c->u.a.lensofar += l;
5772 if (c->u.a.lensofar == c->u.a.totallen) {
5775 c->u.a.outstanding_requests++;
5776 if (agent_query(c->u.a.message,
5779 ssh_agentf_callback, c))
5780 ssh_agentf_callback(c, reply, replylen);
5781 sfree(c->u.a.message);
5782 c->u.a.lensofar = 0;
5785 bufsize = 0; /* agent channels never back up */
5788 if (!c->throttling_conn && bufsize > SSH1_BUFFER_LIMIT) {
5789 c->throttling_conn = 1;
5790 ssh_throttle_conn(ssh, +1);
5795 static void ssh1_smsg_exit_status(Ssh ssh, struct Packet *pktin)
5797 ssh->exitcode = ssh_pkt_getuint32(pktin);
5798 logeventf(ssh, "Server sent command exit status %d", ssh->exitcode);
5799 send_packet(ssh, SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
5801 * In case `helpful' firewalls or proxies tack
5802 * extra human-readable text on the end of the
5803 * session which we might mistake for another
5804 * encrypted packet, we close the session once
5805 * we've sent EXIT_CONFIRMATION.
5807 ssh_disconnect(ssh, NULL, NULL, 0, TRUE);
5810 /* Helper function to deal with sending tty modes for REQUEST_PTY */
5811 static void ssh1_send_ttymode(void *data, char *mode, char *val)
5813 struct Packet *pktout = (struct Packet *)data;
5815 unsigned int arg = 0;
5816 while (strcmp(mode, ssh_ttymodes[i].mode) != 0) i++;
5817 if (i == lenof(ssh_ttymodes)) return;
5818 switch (ssh_ttymodes[i].type) {
5820 arg = ssh_tty_parse_specchar(val);
5823 arg = ssh_tty_parse_boolean(val);
5826 ssh2_pkt_addbyte(pktout, ssh_ttymodes[i].opcode);
5827 ssh2_pkt_addbyte(pktout, arg);
5830 int ssh_agent_forwarding_permitted(Ssh ssh)
5832 return conf_get_int(ssh->conf, CONF_agentfwd) && agent_exists();
5835 static void do_ssh1_connection(Ssh ssh, const unsigned char *in, int inlen,
5836 struct Packet *pktin)
5838 crBegin(ssh->do_ssh1_connection_crstate);
5840 ssh->packet_dispatch[SSH1_SMSG_STDOUT_DATA] =
5841 ssh->packet_dispatch[SSH1_SMSG_STDERR_DATA] =
5842 ssh1_smsg_stdout_stderr_data;
5844 ssh->packet_dispatch[SSH1_MSG_CHANNEL_OPEN_CONFIRMATION] =
5845 ssh1_msg_channel_open_confirmation;
5846 ssh->packet_dispatch[SSH1_MSG_CHANNEL_OPEN_FAILURE] =
5847 ssh1_msg_channel_open_failure;
5848 ssh->packet_dispatch[SSH1_MSG_CHANNEL_CLOSE] =
5849 ssh->packet_dispatch[SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION] =
5850 ssh1_msg_channel_close;
5851 ssh->packet_dispatch[SSH1_MSG_CHANNEL_DATA] = ssh1_msg_channel_data;
5852 ssh->packet_dispatch[SSH1_SMSG_EXIT_STATUS] = ssh1_smsg_exit_status;
5854 if (ssh_agent_forwarding_permitted(ssh)) {
5855 logevent("Requesting agent forwarding");
5856 send_packet(ssh, SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END);
5860 if (pktin->type != SSH1_SMSG_SUCCESS
5861 && pktin->type != SSH1_SMSG_FAILURE) {
5862 bombout(("Protocol confusion"));
5864 } else if (pktin->type == SSH1_SMSG_FAILURE) {
5865 logevent("Agent forwarding refused");
5867 logevent("Agent forwarding enabled");
5868 ssh->agentfwd_enabled = TRUE;
5869 ssh->packet_dispatch[SSH1_SMSG_AGENT_OPEN] = ssh1_smsg_agent_open;
5873 if (conf_get_int(ssh->conf, CONF_x11_forward)) {
5875 x11_setup_display(conf_get_str(ssh->conf, CONF_x11_display),
5877 if (!ssh->x11disp) {
5878 /* FIXME: return an error message from x11_setup_display */
5879 logevent("X11 forwarding not enabled: unable to"
5880 " initialise X display");
5882 ssh->x11auth = x11_invent_fake_auth
5883 (ssh->x11authtree, conf_get_int(ssh->conf, CONF_x11_auth));
5884 ssh->x11auth->disp = ssh->x11disp;
5886 logevent("Requesting X11 forwarding");
5887 if (ssh->v1_local_protoflags & SSH1_PROTOFLAG_SCREEN_NUMBER) {
5888 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
5889 PKT_STR, ssh->x11auth->protoname,
5890 PKT_STR, ssh->x11auth->datastring,
5891 PKT_INT, ssh->x11disp->screennum,
5894 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
5895 PKT_STR, ssh->x11auth->protoname,
5896 PKT_STR, ssh->x11auth->datastring,
5902 if (pktin->type != SSH1_SMSG_SUCCESS
5903 && pktin->type != SSH1_SMSG_FAILURE) {
5904 bombout(("Protocol confusion"));
5906 } else if (pktin->type == SSH1_SMSG_FAILURE) {
5907 logevent("X11 forwarding refused");
5909 logevent("X11 forwarding enabled");
5910 ssh->X11_fwd_enabled = TRUE;
5911 ssh->packet_dispatch[SSH1_SMSG_X11_OPEN] = ssh1_smsg_x11_open;
5916 ssh_setup_portfwd(ssh, ssh->conf);
5917 ssh->packet_dispatch[SSH1_MSG_PORT_OPEN] = ssh1_msg_port_open;
5919 if (!conf_get_int(ssh->conf, CONF_nopty)) {
5921 /* Unpick the terminal-speed string. */
5922 /* XXX perhaps we should allow no speeds to be sent. */
5923 ssh->ospeed = 38400; ssh->ispeed = 38400; /* last-resort defaults */
5924 sscanf(conf_get_str(ssh->conf, CONF_termspeed), "%d,%d", &ssh->ospeed, &ssh->ispeed);
5925 /* Send the pty request. */
5926 pkt = ssh1_pkt_init(SSH1_CMSG_REQUEST_PTY);
5927 ssh_pkt_addstring(pkt, conf_get_str(ssh->conf, CONF_termtype));
5928 ssh_pkt_adduint32(pkt, ssh->term_height);
5929 ssh_pkt_adduint32(pkt, ssh->term_width);
5930 ssh_pkt_adduint32(pkt, 0); /* width in pixels */
5931 ssh_pkt_adduint32(pkt, 0); /* height in pixels */
5932 parse_ttymodes(ssh, ssh1_send_ttymode, (void *)pkt);
5933 ssh_pkt_addbyte(pkt, SSH1_TTY_OP_ISPEED);
5934 ssh_pkt_adduint32(pkt, ssh->ispeed);
5935 ssh_pkt_addbyte(pkt, SSH1_TTY_OP_OSPEED);
5936 ssh_pkt_adduint32(pkt, ssh->ospeed);
5937 ssh_pkt_addbyte(pkt, SSH_TTY_OP_END);
5939 ssh->state = SSH_STATE_INTERMED;
5943 if (pktin->type != SSH1_SMSG_SUCCESS
5944 && pktin->type != SSH1_SMSG_FAILURE) {
5945 bombout(("Protocol confusion"));
5947 } else if (pktin->type == SSH1_SMSG_FAILURE) {
5948 c_write_str(ssh, "Server refused to allocate pty\r\n");
5949 ssh->editing = ssh->echoing = 1;
5951 logeventf(ssh, "Allocated pty (ospeed %dbps, ispeed %dbps)",
5952 ssh->ospeed, ssh->ispeed);
5953 ssh->got_pty = TRUE;
5956 ssh->editing = ssh->echoing = 1;
5959 if (conf_get_int(ssh->conf, CONF_compression)) {
5960 send_packet(ssh, SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END);
5964 if (pktin->type != SSH1_SMSG_SUCCESS
5965 && pktin->type != SSH1_SMSG_FAILURE) {
5966 bombout(("Protocol confusion"));
5968 } else if (pktin->type == SSH1_SMSG_FAILURE) {
5969 c_write_str(ssh, "Server refused to compress\r\n");
5971 logevent("Started compression");
5972 ssh->v1_compressing = TRUE;
5973 ssh->cs_comp_ctx = zlib_compress_init();
5974 logevent("Initialised zlib (RFC1950) compression");
5975 ssh->sc_comp_ctx = zlib_decompress_init();
5976 logevent("Initialised zlib (RFC1950) decompression");
5980 * Start the shell or command.
5982 * Special case: if the first-choice command is an SSH-2
5983 * subsystem (hence not usable here) and the second choice
5984 * exists, we fall straight back to that.
5987 char *cmd = conf_get_str(ssh->conf, CONF_remote_cmd);
5989 if (conf_get_int(ssh->conf, CONF_ssh_subsys) &&
5990 conf_get_str(ssh->conf, CONF_remote_cmd2)) {
5991 cmd = conf_get_str(ssh->conf, CONF_remote_cmd2);
5992 ssh->fallback_cmd = TRUE;
5995 send_packet(ssh, SSH1_CMSG_EXEC_CMD, PKT_STR, cmd, PKT_END);
5997 send_packet(ssh, SSH1_CMSG_EXEC_SHELL, PKT_END);
5998 logevent("Started session");
6001 ssh->state = SSH_STATE_SESSION;
6002 if (ssh->size_needed)
6003 ssh_size(ssh, ssh->term_width, ssh->term_height);
6004 if (ssh->eof_needed)
6005 ssh_special(ssh, TS_EOF);
6008 ldisc_echoedit_update(ssh->ldisc); /* cause ldisc to notice changes */
6010 ssh->channels = newtree234(ssh_channelcmp);
6014 * By this point, most incoming packets are already being
6015 * handled by the dispatch table, and we need only pay
6016 * attention to the unusual ones.
6021 if (pktin->type == SSH1_SMSG_SUCCESS) {
6022 /* may be from EXEC_SHELL on some servers */
6023 } else if (pktin->type == SSH1_SMSG_FAILURE) {
6024 /* may be from EXEC_SHELL on some servers
6025 * if no pty is available or in other odd cases. Ignore */
6027 bombout(("Strange packet received: type %d", pktin->type));
6032 int len = min(inlen, 512);
6033 send_packet(ssh, SSH1_CMSG_STDIN_DATA,
6034 PKT_INT, len, PKT_DATA, in, len,
6046 * Handle the top-level SSH-2 protocol.
6048 static void ssh1_msg_debug(Ssh ssh, struct Packet *pktin)
6053 ssh_pkt_getstring(pktin, &msg, &msglen);
6054 logeventf(ssh, "Remote debug message: %.*s", msglen, msg);
6057 static void ssh1_msg_disconnect(Ssh ssh, struct Packet *pktin)
6059 /* log reason code in disconnect message */
6063 ssh_pkt_getstring(pktin, &msg, &msglen);
6064 bombout(("Server sent disconnect message:\n\"%.*s\"", msglen, msg));
6067 static void ssh_msg_ignore(Ssh ssh, struct Packet *pktin)
6069 /* Do nothing, because we're ignoring it! Duhh. */
6072 static void ssh1_protocol_setup(Ssh ssh)
6077 * Most messages are handled by the coroutines.
6079 for (i = 0; i < 256; i++)
6080 ssh->packet_dispatch[i] = NULL;
6083 * These special message types we install handlers for.
6085 ssh->packet_dispatch[SSH1_MSG_DISCONNECT] = ssh1_msg_disconnect;
6086 ssh->packet_dispatch[SSH1_MSG_IGNORE] = ssh_msg_ignore;
6087 ssh->packet_dispatch[SSH1_MSG_DEBUG] = ssh1_msg_debug;
6090 static void ssh1_protocol(Ssh ssh, const void *vin, int inlen,
6091 struct Packet *pktin)
6093 const unsigned char *in = (const unsigned char *)vin;
6094 if (ssh->state == SSH_STATE_CLOSED)
6097 if (pktin && ssh->packet_dispatch[pktin->type]) {
6098 ssh->packet_dispatch[pktin->type](ssh, pktin);
6102 if (!ssh->protocol_initial_phase_done) {
6103 if (do_ssh1_login(ssh, in, inlen, pktin))
6104 ssh->protocol_initial_phase_done = TRUE;
6109 do_ssh1_connection(ssh, in, inlen, pktin);
6113 * Utility routines for decoding comma-separated strings in KEXINIT.
6115 static int first_in_commasep_string(char const *needle, char const *haystack,
6119 if (!needle || !haystack) /* protect against null pointers */
6121 needlen = strlen(needle);
6123 if (haylen >= needlen && /* haystack is long enough */
6124 !memcmp(needle, haystack, needlen) && /* initial match */
6125 (haylen == needlen || haystack[needlen] == ',')
6126 /* either , or EOS follows */
6132 static int in_commasep_string(char const *needle, char const *haystack,
6137 if (!needle || !haystack) /* protect against null pointers */
6140 * Is it at the start of the string?
6142 if (first_in_commasep_string(needle, haystack, haylen))
6145 * If not, search for the next comma and resume after that.
6146 * If no comma found, terminate.
6148 p = memchr(haystack, ',', haylen);
6150 /* + 1 to skip over comma */
6151 return in_commasep_string(needle, p + 1, haylen - (p + 1 - haystack));
6155 * Add a value to the comma-separated string at the end of the packet.
6157 static void ssh2_pkt_addstring_commasep(struct Packet *pkt, const char *data)
6159 if (pkt->length - pkt->savedpos > 0)
6160 ssh_pkt_addstring_str(pkt, ",");
6161 ssh_pkt_addstring_str(pkt, data);
6166 * SSH-2 key derivation (RFC 4253 section 7.2).
6168 static unsigned char *ssh2_mkkey(Ssh ssh, Bignum K, unsigned char *H,
6169 char chr, int keylen)
6171 const struct ssh_hash *h = ssh->kex->hash;
6179 /* Round up to the next multiple of hash length. */
6180 keylen_padded = ((keylen + h->hlen - 1) / h->hlen) * h->hlen;
6182 key = snewn(keylen_padded, unsigned char);
6184 /* First hlen bytes. */
6186 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
6187 hash_mpint(h, s, K);
6188 h->bytes(s, H, h->hlen);
6189 h->bytes(s, &chr, 1);
6190 h->bytes(s, ssh->v2_session_id, ssh->v2_session_id_len);
6193 /* Subsequent blocks of hlen bytes. */
6194 if (keylen_padded > h->hlen) {
6198 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
6199 hash_mpint(h, s, K);
6200 h->bytes(s, H, h->hlen);
6202 for (offset = h->hlen; offset < keylen_padded; offset += h->hlen) {
6203 h->bytes(s, key + offset - h->hlen, h->hlen);
6205 h->final(s2, key + offset);
6211 /* Now clear any extra bytes of key material beyond the length
6212 * we're officially returning, because the caller won't know to
6214 if (keylen_padded > keylen)
6215 smemclr(key + keylen, keylen_padded - keylen);
6221 * Structure for constructing KEXINIT algorithm lists.
6223 #define MAXKEXLIST 16
6224 struct kexinit_algorithm {
6228 const struct ssh_kex *kex;
6231 const struct ssh_signkey *hostkey;
6233 const struct ssh2_cipher *cipher;
6237 const struct ssh_mac *mac;
6240 const struct ssh_compress *comp;
6245 * Find a slot in a KEXINIT algorithm list to use for a new algorithm.
6246 * If the algorithm is already in the list, return a pointer to its
6247 * entry, otherwise return an entry from the end of the list.
6248 * This assumes that every time a particular name is passed in, it
6249 * comes from the same string constant. If this isn't true, this
6250 * function may need to be rewritten to use strcmp() instead.
6252 static struct kexinit_algorithm *ssh2_kexinit_addalg(struct kexinit_algorithm
6253 *list, const char *name)
6257 for (i = 0; i < MAXKEXLIST; i++)
6258 if (list[i].name == NULL || list[i].name == name) {
6259 list[i].name = name;
6262 assert(!"No space in KEXINIT list");
6267 * Handle the SSH-2 transport layer.
6269 static void do_ssh2_transport(Ssh ssh, const void *vin, int inlen,
6270 struct Packet *pktin)
6272 const unsigned char *in = (const unsigned char *)vin;
6274 KEXLIST_KEX, KEXLIST_HOSTKEY, KEXLIST_CSCIPHER, KEXLIST_SCCIPHER,
6275 KEXLIST_CSMAC, KEXLIST_SCMAC, KEXLIST_CSCOMP, KEXLIST_SCCOMP,
6278 const char * kexlist_descr[NKEXLIST] = {
6279 "key exchange algorithm", "host key algorithm",
6280 "client-to-server cipher", "server-to-client cipher",
6281 "client-to-server MAC", "server-to-client MAC",
6282 "client-to-server compression method",
6283 "server-to-client compression method" };
6284 struct do_ssh2_transport_state {
6286 int nbits, pbits, warn_kex, warn_cscipher, warn_sccipher;
6287 Bignum p, g, e, f, K;
6290 int kex_init_value, kex_reply_value;
6291 const struct ssh_mac **maclist;
6293 const struct ssh2_cipher *cscipher_tobe;
6294 const struct ssh2_cipher *sccipher_tobe;
6295 const struct ssh_mac *csmac_tobe;
6296 const struct ssh_mac *scmac_tobe;
6297 int csmac_etm_tobe, scmac_etm_tobe;
6298 const struct ssh_compress *cscomp_tobe;
6299 const struct ssh_compress *sccomp_tobe;
6300 char *hostkeydata, *sigdata, *rsakeydata, *keystr, *fingerprint;
6301 int hostkeylen, siglen, rsakeylen;
6302 void *hkey; /* actual host key */
6303 void *rsakey; /* for RSA kex */
6304 void *eckey; /* for ECDH kex */
6305 unsigned char exchange_hash[SSH2_KEX_MAX_HASH_LEN];
6306 int n_preferred_kex;
6307 const struct ssh_kexes *preferred_kex[KEX_MAX];
6308 int n_preferred_ciphers;
6309 const struct ssh2_ciphers *preferred_ciphers[CIPHER_MAX];
6310 const struct ssh_compress *preferred_comp;
6311 int userauth_succeeded; /* for delayed compression */
6312 int pending_compression;
6313 int got_session_id, activated_authconn;
6314 struct Packet *pktout;
6318 struct kexinit_algorithm kexlists[NKEXLIST][MAXKEXLIST];
6320 crState(do_ssh2_transport_state);
6322 assert(!ssh->bare_connection);
6326 s->cscipher_tobe = s->sccipher_tobe = NULL;
6327 s->csmac_tobe = s->scmac_tobe = NULL;
6328 s->cscomp_tobe = s->sccomp_tobe = NULL;
6330 s->got_session_id = s->activated_authconn = FALSE;
6331 s->userauth_succeeded = FALSE;
6332 s->pending_compression = FALSE;
6335 * Be prepared to work around the buggy MAC problem.
6337 if (ssh->remote_bugs & BUG_SSH2_HMAC)
6338 s->maclist = buggymacs, s->nmacs = lenof(buggymacs);
6340 s->maclist = macs, s->nmacs = lenof(macs);
6343 ssh->pkt_kctx = SSH2_PKTCTX_NOKEX;
6346 struct kexinit_algorithm *alg;
6349 * Set up the preferred key exchange. (NULL => warn below here)
6351 s->n_preferred_kex = 0;
6352 for (i = 0; i < KEX_MAX; i++) {
6353 switch (conf_get_int_int(ssh->conf, CONF_ssh_kexlist, i)) {
6355 s->preferred_kex[s->n_preferred_kex++] =
6356 &ssh_diffiehellman_gex;
6359 s->preferred_kex[s->n_preferred_kex++] =
6360 &ssh_diffiehellman_group14;
6363 s->preferred_kex[s->n_preferred_kex++] =
6364 &ssh_diffiehellman_group1;
6367 s->preferred_kex[s->n_preferred_kex++] =
6371 s->preferred_kex[s->n_preferred_kex++] =
6375 /* Flag for later. Don't bother if it's the last in
6377 if (i < KEX_MAX - 1) {
6378 s->preferred_kex[s->n_preferred_kex++] = NULL;
6385 * Set up the preferred ciphers. (NULL => warn below here)
6387 s->n_preferred_ciphers = 0;
6388 for (i = 0; i < CIPHER_MAX; i++) {
6389 switch (conf_get_int_int(ssh->conf, CONF_ssh_cipherlist, i)) {
6390 case CIPHER_BLOWFISH:
6391 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_blowfish;
6394 if (conf_get_int(ssh->conf, CONF_ssh2_des_cbc)) {
6395 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_des;
6399 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_3des;
6402 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_aes;
6404 case CIPHER_ARCFOUR:
6405 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_arcfour;
6407 case CIPHER_CHACHA20:
6408 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_ccp;
6411 /* Flag for later. Don't bother if it's the last in
6413 if (i < CIPHER_MAX - 1) {
6414 s->preferred_ciphers[s->n_preferred_ciphers++] = NULL;
6421 * Set up preferred compression.
6423 if (conf_get_int(ssh->conf, CONF_compression))
6424 s->preferred_comp = &ssh_zlib;
6426 s->preferred_comp = &ssh_comp_none;
6429 * Enable queueing of outgoing auth- or connection-layer
6430 * packets while we are in the middle of a key exchange.
6432 ssh->queueing = TRUE;
6435 * Flag that KEX is in progress.
6437 ssh->kex_in_progress = TRUE;
6439 for (i = 0; i < NKEXLIST; i++)
6440 for (j = 0; j < MAXKEXLIST; j++)
6441 s->kexlists[i][j].name = NULL;
6442 /* List key exchange algorithms. */
6444 for (i = 0; i < s->n_preferred_kex; i++) {
6445 const struct ssh_kexes *k = s->preferred_kex[i];
6446 if (!k) warn = TRUE;
6447 else for (j = 0; j < k->nkexes; j++) {
6448 alg = ssh2_kexinit_addalg(s->kexlists[KEXLIST_KEX],
6450 alg->u.kex.kex = k->list[j];
6451 alg->u.kex.warn = warn;
6454 /* List server host key algorithms. */
6455 if (!s->got_session_id) {
6457 * In the first key exchange, we list all the algorithms
6458 * we're prepared to cope with, but prefer those algorithms
6459 * for which we have a host key for this host.
6461 for (i = 0; i < lenof(hostkey_algs); i++) {
6462 if (have_ssh_host_key(ssh->savedhost, ssh->savedport,
6463 hostkey_algs[i]->keytype)) {
6464 alg = ssh2_kexinit_addalg(s->kexlists[KEXLIST_HOSTKEY],
6465 hostkey_algs[i]->name);
6466 alg->u.hostkey = hostkey_algs[i];
6469 for (i = 0; i < lenof(hostkey_algs); i++) {
6470 alg = ssh2_kexinit_addalg(s->kexlists[KEXLIST_HOSTKEY],
6471 hostkey_algs[i]->name);
6472 alg->u.hostkey = hostkey_algs[i];
6476 * In subsequent key exchanges, we list only the kex
6477 * algorithm that was selected in the first key exchange,
6478 * so that we keep getting the same host key and hence
6479 * don't have to interrupt the user's session to ask for
6483 alg = ssh2_kexinit_addalg(s->kexlists[KEXLIST_HOSTKEY],
6484 ssh->hostkey->name);
6485 alg->u.hostkey = ssh->hostkey;
6487 /* List encryption algorithms (client->server then server->client). */
6488 for (k = KEXLIST_CSCIPHER; k <= KEXLIST_SCCIPHER; k++) {
6490 for (i = 0; i < s->n_preferred_ciphers; i++) {
6491 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
6492 if (!c) warn = TRUE;
6493 else for (j = 0; j < c->nciphers; j++) {
6494 alg = ssh2_kexinit_addalg(s->kexlists[k],
6496 alg->u.cipher.cipher = c->list[j];
6497 alg->u.cipher.warn = warn;
6501 /* List MAC algorithms (client->server then server->client). */
6502 for (j = KEXLIST_CSMAC; j <= KEXLIST_SCMAC; j++) {
6503 for (i = 0; i < s->nmacs; i++) {
6504 alg = ssh2_kexinit_addalg(s->kexlists[j], s->maclist[i]->name);
6505 alg->u.mac.mac = s->maclist[i];
6506 alg->u.mac.etm = FALSE;
6508 for (i = 0; i < s->nmacs; i++)
6509 /* For each MAC, there may also be an ETM version,
6510 * which we list second. */
6511 if (s->maclist[i]->etm_name) {
6512 alg = ssh2_kexinit_addalg(s->kexlists[j],
6513 s->maclist[i]->etm_name);
6514 alg->u.mac.mac = s->maclist[i];
6515 alg->u.mac.etm = TRUE;
6518 /* List client->server compression algorithms,
6519 * then server->client compression algorithms. (We use the
6520 * same set twice.) */
6521 for (j = KEXLIST_CSCOMP; j <= KEXLIST_SCCOMP; j++) {
6522 assert(lenof(compressions) > 1);
6523 /* Prefer non-delayed versions */
6524 alg = ssh2_kexinit_addalg(s->kexlists[j], s->preferred_comp->name);
6525 alg->u.comp = s->preferred_comp;
6526 /* We don't even list delayed versions of algorithms until
6527 * they're allowed to be used, to avoid a race. See the end of
6529 if (s->userauth_succeeded && s->preferred_comp->delayed_name) {
6530 alg = ssh2_kexinit_addalg(s->kexlists[j],
6531 s->preferred_comp->delayed_name);
6532 alg->u.comp = s->preferred_comp;
6534 for (i = 0; i < lenof(compressions); i++) {
6535 const struct ssh_compress *c = compressions[i];
6536 alg = ssh2_kexinit_addalg(s->kexlists[j], c->name);
6538 if (s->userauth_succeeded && c->delayed_name) {
6539 alg = ssh2_kexinit_addalg(s->kexlists[j], c->delayed_name);
6545 * Construct and send our key exchange packet.
6547 s->pktout = ssh2_pkt_init(SSH2_MSG_KEXINIT);
6548 for (i = 0; i < 16; i++)
6549 ssh2_pkt_addbyte(s->pktout, (unsigned char) random_byte());
6550 for (i = 0; i < NKEXLIST; i++) {
6551 ssh2_pkt_addstring_start(s->pktout);
6552 for (j = 0; j < MAXKEXLIST; j++) {
6553 if (s->kexlists[i][j].name == NULL) break;
6554 ssh2_pkt_addstring_commasep(s->pktout, s->kexlists[i][j].name);
6557 /* List client->server languages. Empty list. */
6558 ssh2_pkt_addstring_start(s->pktout);
6559 /* List server->client languages. Empty list. */
6560 ssh2_pkt_addstring_start(s->pktout);
6561 /* First KEX packet does _not_ follow, because we're not that brave. */
6562 ssh2_pkt_addbool(s->pktout, FALSE);
6564 ssh2_pkt_adduint32(s->pktout, 0);
6567 s->our_kexinitlen = s->pktout->length - 5;
6568 s->our_kexinit = snewn(s->our_kexinitlen, unsigned char);
6569 memcpy(s->our_kexinit, s->pktout->data + 5, s->our_kexinitlen);
6571 ssh2_pkt_send_noqueue(ssh, s->pktout);
6574 crWaitUntilV(pktin);
6577 * Now examine the other side's KEXINIT to see what we're up
6584 if (pktin->type != SSH2_MSG_KEXINIT) {
6585 bombout(("expected key exchange packet from server"));
6589 ssh->hostkey = NULL;
6590 s->cscipher_tobe = NULL;
6591 s->sccipher_tobe = NULL;
6592 s->csmac_tobe = NULL;
6593 s->scmac_tobe = NULL;
6594 s->cscomp_tobe = NULL;
6595 s->sccomp_tobe = NULL;
6596 s->warn_kex = s->warn_cscipher = s->warn_sccipher = FALSE;
6598 pktin->savedpos += 16; /* skip garbage cookie */
6601 for (i = 0; i < NKEXLIST; i++) {
6602 ssh_pkt_getstring(pktin, &str, &len);
6604 bombout(("KEXINIT packet was incomplete"));
6608 /* If we've already selected a cipher which requires a
6609 * particular MAC, then just select that, and don't even
6610 * bother looking through the server's KEXINIT string for
6612 if (i == KEXLIST_CSMAC && s->cscipher_tobe &&
6613 s->cscipher_tobe->required_mac) {
6614 s->csmac_tobe = s->cscipher_tobe->required_mac;
6615 s->csmac_etm_tobe = !!(s->csmac_tobe->etm_name);
6618 if (i == KEXLIST_SCMAC && s->sccipher_tobe &&
6619 s->sccipher_tobe->required_mac) {
6620 s->scmac_tobe = s->sccipher_tobe->required_mac;
6621 s->scmac_etm_tobe = !!(s->scmac_tobe->etm_name);
6625 for (j = 0; j < MAXKEXLIST; j++) {
6626 struct kexinit_algorithm *alg = &s->kexlists[i][j];
6627 if (alg->name == NULL) break;
6628 if (in_commasep_string(alg->name, str, len)) {
6629 /* We've found a matching algorithm. */
6630 if (i == KEXLIST_KEX || i == KEXLIST_HOSTKEY) {
6631 /* Check if we might need to ignore first kex pkt */
6633 !first_in_commasep_string(alg->name, str, len))
6636 if (i == KEXLIST_KEX) {
6637 ssh->kex = alg->u.kex.kex;
6638 s->warn_kex = alg->u.kex.warn;
6639 } else if (i == KEXLIST_HOSTKEY) {
6640 ssh->hostkey = alg->u.hostkey;
6641 } else if (i == KEXLIST_CSCIPHER) {
6642 s->cscipher_tobe = alg->u.cipher.cipher;
6643 s->warn_cscipher = alg->u.cipher.warn;
6644 } else if (i == KEXLIST_SCCIPHER) {
6645 s->sccipher_tobe = alg->u.cipher.cipher;
6646 s->warn_sccipher = alg->u.cipher.warn;
6647 } else if (i == KEXLIST_CSMAC) {
6648 s->csmac_tobe = alg->u.mac.mac;
6649 s->csmac_etm_tobe = alg->u.mac.etm;
6650 } else if (i == KEXLIST_SCMAC) {
6651 s->scmac_tobe = alg->u.mac.mac;
6652 s->scmac_etm_tobe = alg->u.mac.etm;
6653 } else if (i == KEXLIST_CSCOMP) {
6654 s->cscomp_tobe = alg->u.comp;
6655 } else if (i == KEXLIST_SCCOMP) {
6656 s->sccomp_tobe = alg->u.comp;
6660 if ((i == KEXLIST_CSCOMP || i == KEXLIST_SCCOMP) &&
6661 in_commasep_string(alg->u.comp->delayed_name, str, len))
6662 s->pending_compression = TRUE; /* try this later */
6664 bombout(("Couldn't agree a %s ((available: %.*s)",
6665 kexlist_descr[i], len, str));
6670 if (s->pending_compression) {
6671 logevent("Server supports delayed compression; "
6672 "will try this later");
6674 ssh_pkt_getstring(pktin, &str, &len); /* client->server language */
6675 ssh_pkt_getstring(pktin, &str, &len); /* server->client language */
6676 s->ignorepkt = ssh2_pkt_getbool(pktin) && !s->guessok;
6678 ssh->exhash = ssh->kex->hash->init();
6679 hash_string(ssh->kex->hash, ssh->exhash, ssh->v_c, strlen(ssh->v_c));
6680 hash_string(ssh->kex->hash, ssh->exhash, ssh->v_s, strlen(ssh->v_s));
6681 hash_string(ssh->kex->hash, ssh->exhash,
6682 s->our_kexinit, s->our_kexinitlen);
6683 sfree(s->our_kexinit);
6684 /* Include the type byte in the hash of server's KEXINIT */
6685 hash_string(ssh->kex->hash, ssh->exhash,
6686 pktin->body - 1, pktin->length + 1);
6689 ssh_set_frozen(ssh, 1);
6690 s->dlgret = askalg(ssh->frontend, "key-exchange algorithm",
6692 ssh_dialog_callback, ssh);
6693 if (s->dlgret < 0) {
6697 bombout(("Unexpected data from server while"
6698 " waiting for user response"));
6701 } while (pktin || inlen > 0);
6702 s->dlgret = ssh->user_response;
6704 ssh_set_frozen(ssh, 0);
6705 if (s->dlgret == 0) {
6706 ssh_disconnect(ssh, "User aborted at kex warning", NULL,
6712 if (s->warn_cscipher) {
6713 ssh_set_frozen(ssh, 1);
6714 s->dlgret = askalg(ssh->frontend,
6715 "client-to-server cipher",
6716 s->cscipher_tobe->name,
6717 ssh_dialog_callback, ssh);
6718 if (s->dlgret < 0) {
6722 bombout(("Unexpected data from server while"
6723 " waiting for user response"));
6726 } while (pktin || inlen > 0);
6727 s->dlgret = ssh->user_response;
6729 ssh_set_frozen(ssh, 0);
6730 if (s->dlgret == 0) {
6731 ssh_disconnect(ssh, "User aborted at cipher warning", NULL,
6737 if (s->warn_sccipher) {
6738 ssh_set_frozen(ssh, 1);
6739 s->dlgret = askalg(ssh->frontend,
6740 "server-to-client cipher",
6741 s->sccipher_tobe->name,
6742 ssh_dialog_callback, ssh);
6743 if (s->dlgret < 0) {
6747 bombout(("Unexpected data from server while"
6748 " waiting for user response"));
6751 } while (pktin || inlen > 0);
6752 s->dlgret = ssh->user_response;
6754 ssh_set_frozen(ssh, 0);
6755 if (s->dlgret == 0) {
6756 ssh_disconnect(ssh, "User aborted at cipher warning", NULL,
6762 if (s->ignorepkt) /* first_kex_packet_follows */
6763 crWaitUntilV(pktin); /* Ignore packet */
6766 if (ssh->kex->main_type == KEXTYPE_DH) {
6768 * Work out the number of bits of key we will need from the
6769 * key exchange. We start with the maximum key length of
6775 csbits = s->cscipher_tobe->real_keybits;
6776 scbits = s->sccipher_tobe->real_keybits;
6777 s->nbits = (csbits > scbits ? csbits : scbits);
6779 /* The keys only have hlen-bit entropy, since they're based on
6780 * a hash. So cap the key size at hlen bits. */
6781 if (s->nbits > ssh->kex->hash->hlen * 8)
6782 s->nbits = ssh->kex->hash->hlen * 8;
6785 * If we're doing Diffie-Hellman group exchange, start by
6786 * requesting a group.
6788 if (dh_is_gex(ssh->kex)) {
6789 logevent("Doing Diffie-Hellman group exchange");
6790 ssh->pkt_kctx = SSH2_PKTCTX_DHGEX;
6792 * Work out how big a DH group we will need to allow that
6795 s->pbits = 512 << ((s->nbits - 1) / 64);
6796 if (s->pbits < DH_MIN_SIZE)
6797 s->pbits = DH_MIN_SIZE;
6798 if (s->pbits > DH_MAX_SIZE)
6799 s->pbits = DH_MAX_SIZE;
6800 if ((ssh->remote_bugs & BUG_SSH2_OLDGEX)) {
6801 s->pktout = ssh2_pkt_init(SSH2_MSG_KEX_DH_GEX_REQUEST_OLD);
6802 ssh2_pkt_adduint32(s->pktout, s->pbits);
6804 s->pktout = ssh2_pkt_init(SSH2_MSG_KEX_DH_GEX_REQUEST);
6805 ssh2_pkt_adduint32(s->pktout, DH_MIN_SIZE);
6806 ssh2_pkt_adduint32(s->pktout, s->pbits);
6807 ssh2_pkt_adduint32(s->pktout, DH_MAX_SIZE);
6809 ssh2_pkt_send_noqueue(ssh, s->pktout);
6811 crWaitUntilV(pktin);
6812 if (pktin->type != SSH2_MSG_KEX_DH_GEX_GROUP) {
6813 bombout(("expected key exchange group packet from server"));
6816 s->p = ssh2_pkt_getmp(pktin);
6817 s->g = ssh2_pkt_getmp(pktin);
6818 if (!s->p || !s->g) {
6819 bombout(("unable to read mp-ints from incoming group packet"));
6822 ssh->kex_ctx = dh_setup_gex(s->p, s->g);
6823 s->kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT;
6824 s->kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY;
6826 ssh->pkt_kctx = SSH2_PKTCTX_DHGROUP;
6827 ssh->kex_ctx = dh_setup_group(ssh->kex);
6828 s->kex_init_value = SSH2_MSG_KEXDH_INIT;
6829 s->kex_reply_value = SSH2_MSG_KEXDH_REPLY;
6830 logeventf(ssh, "Using Diffie-Hellman with standard group \"%s\"",
6831 ssh->kex->groupname);
6834 logeventf(ssh, "Doing Diffie-Hellman key exchange with hash %s",
6835 ssh->kex->hash->text_name);
6837 * Now generate and send e for Diffie-Hellman.
6839 set_busy_status(ssh->frontend, BUSY_CPU); /* this can take a while */
6840 s->e = dh_create_e(ssh->kex_ctx, s->nbits * 2);
6841 s->pktout = ssh2_pkt_init(s->kex_init_value);
6842 ssh2_pkt_addmp(s->pktout, s->e);
6843 ssh2_pkt_send_noqueue(ssh, s->pktout);
6845 set_busy_status(ssh->frontend, BUSY_WAITING); /* wait for server */
6846 crWaitUntilV(pktin);
6847 if (pktin->type != s->kex_reply_value) {
6848 bombout(("expected key exchange reply packet from server"));
6851 set_busy_status(ssh->frontend, BUSY_CPU); /* cogitate */
6852 ssh_pkt_getstring(pktin, &s->hostkeydata, &s->hostkeylen);
6853 if (!s->hostkeydata) {
6854 bombout(("unable to parse key exchange reply packet"));
6857 s->hkey = ssh->hostkey->newkey(ssh->hostkey,
6858 s->hostkeydata, s->hostkeylen);
6859 s->f = ssh2_pkt_getmp(pktin);
6861 bombout(("unable to parse key exchange reply packet"));
6864 ssh_pkt_getstring(pktin, &s->sigdata, &s->siglen);
6866 bombout(("unable to parse key exchange reply packet"));
6871 const char *err = dh_validate_f(ssh->kex_ctx, s->f);
6873 bombout(("key exchange reply failed validation: %s", err));
6877 s->K = dh_find_K(ssh->kex_ctx, s->f);
6879 /* We assume everything from now on will be quick, and it might
6880 * involve user interaction. */
6881 set_busy_status(ssh->frontend, BUSY_NOT);
6883 hash_string(ssh->kex->hash, ssh->exhash, s->hostkeydata, s->hostkeylen);
6884 if (dh_is_gex(ssh->kex)) {
6885 if (!(ssh->remote_bugs & BUG_SSH2_OLDGEX))
6886 hash_uint32(ssh->kex->hash, ssh->exhash, DH_MIN_SIZE);
6887 hash_uint32(ssh->kex->hash, ssh->exhash, s->pbits);
6888 if (!(ssh->remote_bugs & BUG_SSH2_OLDGEX))
6889 hash_uint32(ssh->kex->hash, ssh->exhash, DH_MAX_SIZE);
6890 hash_mpint(ssh->kex->hash, ssh->exhash, s->p);
6891 hash_mpint(ssh->kex->hash, ssh->exhash, s->g);
6893 hash_mpint(ssh->kex->hash, ssh->exhash, s->e);
6894 hash_mpint(ssh->kex->hash, ssh->exhash, s->f);
6896 dh_cleanup(ssh->kex_ctx);
6898 if (dh_is_gex(ssh->kex)) {
6902 } else if (ssh->kex->main_type == KEXTYPE_ECDH) {
6904 logeventf(ssh, "Doing ECDH key exchange with curve %s and hash %s",
6905 ssh_ecdhkex_curve_textname(ssh->kex),
6906 ssh->kex->hash->text_name);
6907 ssh->pkt_kctx = SSH2_PKTCTX_ECDHKEX;
6909 s->eckey = ssh_ecdhkex_newkey(ssh->kex);
6911 bombout(("Unable to generate key for ECDH"));
6917 int publicPointLength;
6918 publicPoint = ssh_ecdhkex_getpublic(s->eckey, &publicPointLength);
6920 ssh_ecdhkex_freekey(s->eckey);
6921 bombout(("Unable to encode public key for ECDH"));
6924 s->pktout = ssh2_pkt_init(SSH2_MSG_KEX_ECDH_INIT);
6925 ssh2_pkt_addstring_start(s->pktout);
6926 ssh2_pkt_addstring_data(s->pktout, publicPoint, publicPointLength);
6930 ssh2_pkt_send_noqueue(ssh, s->pktout);
6932 crWaitUntilV(pktin);
6933 if (pktin->type != SSH2_MSG_KEX_ECDH_REPLY) {
6934 ssh_ecdhkex_freekey(s->eckey);
6935 bombout(("expected ECDH reply packet from server"));
6939 ssh_pkt_getstring(pktin, &s->hostkeydata, &s->hostkeylen);
6940 if (!s->hostkeydata) {
6941 bombout(("unable to parse ECDH reply packet"));
6944 hash_string(ssh->kex->hash, ssh->exhash, s->hostkeydata, s->hostkeylen);
6945 s->hkey = ssh->hostkey->newkey(ssh->hostkey,
6946 s->hostkeydata, s->hostkeylen);
6950 int publicPointLength;
6951 publicPoint = ssh_ecdhkex_getpublic(s->eckey, &publicPointLength);
6953 ssh_ecdhkex_freekey(s->eckey);
6954 bombout(("Unable to encode public key for ECDH hash"));
6957 hash_string(ssh->kex->hash, ssh->exhash,
6958 publicPoint, publicPointLength);
6965 ssh_pkt_getstring(pktin, &keydata, &keylen);
6967 bombout(("unable to parse ECDH reply packet"));
6970 hash_string(ssh->kex->hash, ssh->exhash, keydata, keylen);
6971 s->K = ssh_ecdhkex_getkey(s->eckey, keydata, keylen);
6973 ssh_ecdhkex_freekey(s->eckey);
6974 bombout(("point received in ECDH was not valid"));
6979 ssh_pkt_getstring(pktin, &s->sigdata, &s->siglen);
6981 bombout(("unable to parse key exchange reply packet"));
6985 ssh_ecdhkex_freekey(s->eckey);
6987 logeventf(ssh, "Doing RSA key exchange with hash %s",
6988 ssh->kex->hash->text_name);
6989 ssh->pkt_kctx = SSH2_PKTCTX_RSAKEX;
6991 * RSA key exchange. First expect a KEXRSA_PUBKEY packet
6994 crWaitUntilV(pktin);
6995 if (pktin->type != SSH2_MSG_KEXRSA_PUBKEY) {
6996 bombout(("expected RSA public key packet from server"));
7000 ssh_pkt_getstring(pktin, &s->hostkeydata, &s->hostkeylen);
7001 if (!s->hostkeydata) {
7002 bombout(("unable to parse RSA public key packet"));
7005 hash_string(ssh->kex->hash, ssh->exhash,
7006 s->hostkeydata, s->hostkeylen);
7007 s->hkey = ssh->hostkey->newkey(ssh->hostkey,
7008 s->hostkeydata, s->hostkeylen);
7012 ssh_pkt_getstring(pktin, &keydata, &s->rsakeylen);
7014 bombout(("unable to parse RSA public key packet"));
7017 s->rsakeydata = snewn(s->rsakeylen, char);
7018 memcpy(s->rsakeydata, keydata, s->rsakeylen);
7021 s->rsakey = ssh_rsakex_newkey(s->rsakeydata, s->rsakeylen);
7023 sfree(s->rsakeydata);
7024 bombout(("unable to parse RSA public key from server"));
7028 hash_string(ssh->kex->hash, ssh->exhash, s->rsakeydata, s->rsakeylen);
7031 * Next, set up a shared secret K, of precisely KLEN -
7032 * 2*HLEN - 49 bits, where KLEN is the bit length of the
7033 * RSA key modulus and HLEN is the bit length of the hash
7037 int klen = ssh_rsakex_klen(s->rsakey);
7038 int nbits = klen - (2*ssh->kex->hash->hlen*8 + 49);
7040 unsigned char *kstr1, *kstr2, *outstr;
7041 int kstr1len, kstr2len, outstrlen;
7043 s->K = bn_power_2(nbits - 1);
7045 for (i = 0; i < nbits; i++) {
7047 byte = random_byte();
7049 bignum_set_bit(s->K, i, (byte >> (i & 7)) & 1);
7053 * Encode this as an mpint.
7055 kstr1 = ssh2_mpint_fmt(s->K, &kstr1len);
7056 kstr2 = snewn(kstr2len = 4 + kstr1len, unsigned char);
7057 PUT_32BIT(kstr2, kstr1len);
7058 memcpy(kstr2 + 4, kstr1, kstr1len);
7061 * Encrypt it with the given RSA key.
7063 outstrlen = (klen + 7) / 8;
7064 outstr = snewn(outstrlen, unsigned char);
7065 ssh_rsakex_encrypt(ssh->kex->hash, kstr2, kstr2len,
7066 outstr, outstrlen, s->rsakey);
7069 * And send it off in a return packet.
7071 s->pktout = ssh2_pkt_init(SSH2_MSG_KEXRSA_SECRET);
7072 ssh2_pkt_addstring_start(s->pktout);
7073 ssh2_pkt_addstring_data(s->pktout, (char *)outstr, outstrlen);
7074 ssh2_pkt_send_noqueue(ssh, s->pktout);
7076 hash_string(ssh->kex->hash, ssh->exhash, outstr, outstrlen);
7083 ssh_rsakex_freekey(s->rsakey);
7085 crWaitUntilV(pktin);
7086 if (pktin->type != SSH2_MSG_KEXRSA_DONE) {
7087 sfree(s->rsakeydata);
7088 bombout(("expected signature packet from server"));
7092 ssh_pkt_getstring(pktin, &s->sigdata, &s->siglen);
7094 bombout(("unable to parse signature packet"));
7098 sfree(s->rsakeydata);
7101 hash_mpint(ssh->kex->hash, ssh->exhash, s->K);
7102 assert(ssh->kex->hash->hlen <= sizeof(s->exchange_hash));
7103 ssh->kex->hash->final(ssh->exhash, s->exchange_hash);
7105 ssh->kex_ctx = NULL;
7108 debug(("Exchange hash is:\n"));
7109 dmemdump(s->exchange_hash, ssh->kex->hash->hlen);
7113 !ssh->hostkey->verifysig(s->hkey, s->sigdata, s->siglen,
7114 (char *)s->exchange_hash,
7115 ssh->kex->hash->hlen)) {
7116 bombout(("Server's host key did not match the signature supplied"));
7120 s->keystr = ssh->hostkey->fmtkey(s->hkey);
7121 if (!s->got_session_id) {
7123 * Authenticate remote host: verify host key. (We've already
7124 * checked the signature of the exchange hash.)
7126 s->fingerprint = ssh2_fingerprint(ssh->hostkey, s->hkey);
7127 logevent("Host key fingerprint is:");
7128 logevent(s->fingerprint);
7129 /* First check against manually configured host keys. */
7130 s->dlgret = verify_ssh_manual_host_key(ssh, s->fingerprint,
7131 ssh->hostkey, s->hkey);
7132 if (s->dlgret == 0) { /* did not match */
7133 bombout(("Host key did not appear in manually configured list"));
7135 } else if (s->dlgret < 0) { /* none configured; use standard handling */
7136 ssh_set_frozen(ssh, 1);
7137 s->dlgret = verify_ssh_host_key(ssh->frontend,
7138 ssh->savedhost, ssh->savedport,
7139 ssh->hostkey->keytype, s->keystr,
7141 ssh_dialog_callback, ssh);
7142 if (s->dlgret < 0) {
7146 bombout(("Unexpected data from server while waiting"
7147 " for user host key response"));
7150 } while (pktin || inlen > 0);
7151 s->dlgret = ssh->user_response;
7153 ssh_set_frozen(ssh, 0);
7154 if (s->dlgret == 0) {
7155 ssh_disconnect(ssh, "Aborted at host key verification", NULL,
7160 sfree(s->fingerprint);
7162 * Save this host key, to check against the one presented in
7163 * subsequent rekeys.
7165 ssh->hostkey_str = s->keystr;
7168 * In a rekey, we never present an interactive host key
7169 * verification request to the user. Instead, we simply
7170 * enforce that the key we're seeing this time is identical to
7171 * the one we saw before.
7173 if (strcmp(ssh->hostkey_str, s->keystr)) {
7174 bombout(("Host key was different in repeat key exchange"));
7179 ssh->hostkey->freekey(s->hkey);
7182 * The exchange hash from the very first key exchange is also
7183 * the session id, used in session key construction and
7186 if (!s->got_session_id) {
7187 assert(sizeof(s->exchange_hash) <= sizeof(ssh->v2_session_id));
7188 memcpy(ssh->v2_session_id, s->exchange_hash,
7189 sizeof(s->exchange_hash));
7190 ssh->v2_session_id_len = ssh->kex->hash->hlen;
7191 assert(ssh->v2_session_id_len <= sizeof(ssh->v2_session_id));
7192 s->got_session_id = TRUE;
7196 * Send SSH2_MSG_NEWKEYS.
7198 s->pktout = ssh2_pkt_init(SSH2_MSG_NEWKEYS);
7199 ssh2_pkt_send_noqueue(ssh, s->pktout);
7200 ssh->outgoing_data_size = 0; /* start counting from here */
7203 * We've sent client NEWKEYS, so create and initialise
7204 * client-to-server session keys.
7206 if (ssh->cs_cipher_ctx)
7207 ssh->cscipher->free_context(ssh->cs_cipher_ctx);
7208 ssh->cscipher = s->cscipher_tobe;
7209 ssh->cs_cipher_ctx = ssh->cscipher->make_context();
7211 if (ssh->cs_mac_ctx)
7212 ssh->csmac->free_context(ssh->cs_mac_ctx);
7213 ssh->csmac = s->csmac_tobe;
7214 ssh->csmac_etm = s->csmac_etm_tobe;
7215 ssh->cs_mac_ctx = ssh->csmac->make_context(ssh->cs_cipher_ctx);
7217 if (ssh->cs_comp_ctx)
7218 ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
7219 ssh->cscomp = s->cscomp_tobe;
7220 ssh->cs_comp_ctx = ssh->cscomp->compress_init();
7223 * Set IVs on client-to-server keys. Here we use the exchange
7224 * hash from the _first_ key exchange.
7229 key = ssh2_mkkey(ssh, s->K, s->exchange_hash, 'C',
7230 ssh->cscipher->padded_keybytes);
7231 ssh->cscipher->setkey(ssh->cs_cipher_ctx, key);
7232 smemclr(key, ssh->cscipher->padded_keybytes);
7235 key = ssh2_mkkey(ssh, s->K, s->exchange_hash, 'A',
7236 ssh->cscipher->blksize);
7237 ssh->cscipher->setiv(ssh->cs_cipher_ctx, key);
7238 smemclr(key, ssh->cscipher->blksize);
7241 key = ssh2_mkkey(ssh, s->K, s->exchange_hash, 'E',
7242 ssh->csmac->keylen);
7243 ssh->csmac->setkey(ssh->cs_mac_ctx, key);
7244 smemclr(key, ssh->csmac->keylen);
7248 logeventf(ssh, "Initialised %.200s client->server encryption",
7249 ssh->cscipher->text_name);
7250 logeventf(ssh, "Initialised %.200s client->server MAC algorithm%s%s",
7251 ssh->csmac->text_name,
7252 ssh->csmac_etm ? " (in ETM mode)" : "",
7253 ssh->cscipher->required_mac ? " (required by cipher)" : "");
7254 if (ssh->cscomp->text_name)
7255 logeventf(ssh, "Initialised %s compression",
7256 ssh->cscomp->text_name);
7259 * Now our end of the key exchange is complete, we can send all
7260 * our queued higher-layer packets.
7262 ssh->queueing = FALSE;
7263 ssh2_pkt_queuesend(ssh);
7266 * Expect SSH2_MSG_NEWKEYS from server.
7268 crWaitUntilV(pktin);
7269 if (pktin->type != SSH2_MSG_NEWKEYS) {
7270 bombout(("expected new-keys packet from server"));
7273 ssh->incoming_data_size = 0; /* start counting from here */
7276 * We've seen server NEWKEYS, so create and initialise
7277 * server-to-client session keys.
7279 if (ssh->sc_cipher_ctx)
7280 ssh->sccipher->free_context(ssh->sc_cipher_ctx);
7281 ssh->sccipher = s->sccipher_tobe;
7282 ssh->sc_cipher_ctx = ssh->sccipher->make_context();
7284 if (ssh->sc_mac_ctx)
7285 ssh->scmac->free_context(ssh->sc_mac_ctx);
7286 ssh->scmac = s->scmac_tobe;
7287 ssh->scmac_etm = s->scmac_etm_tobe;
7288 ssh->sc_mac_ctx = ssh->scmac->make_context(ssh->sc_cipher_ctx);
7290 if (ssh->sc_comp_ctx)
7291 ssh->sccomp->decompress_cleanup(ssh->sc_comp_ctx);
7292 ssh->sccomp = s->sccomp_tobe;
7293 ssh->sc_comp_ctx = ssh->sccomp->decompress_init();
7296 * Set IVs on server-to-client keys. Here we use the exchange
7297 * hash from the _first_ key exchange.
7302 key = ssh2_mkkey(ssh, s->K, s->exchange_hash, 'D',
7303 ssh->sccipher->padded_keybytes);
7304 ssh->sccipher->setkey(ssh->sc_cipher_ctx, key);
7305 smemclr(key, ssh->sccipher->padded_keybytes);
7308 key = ssh2_mkkey(ssh, s->K, s->exchange_hash, 'B',
7309 ssh->sccipher->blksize);
7310 ssh->sccipher->setiv(ssh->sc_cipher_ctx, key);
7311 smemclr(key, ssh->sccipher->blksize);
7314 key = ssh2_mkkey(ssh, s->K, s->exchange_hash, 'F',
7315 ssh->scmac->keylen);
7316 ssh->scmac->setkey(ssh->sc_mac_ctx, key);
7317 smemclr(key, ssh->scmac->keylen);
7320 logeventf(ssh, "Initialised %.200s server->client encryption",
7321 ssh->sccipher->text_name);
7322 logeventf(ssh, "Initialised %.200s server->client MAC algorithm%s%s",
7323 ssh->scmac->text_name,
7324 ssh->scmac_etm ? " (in ETM mode)" : "",
7325 ssh->sccipher->required_mac ? " (required by cipher)" : "");
7326 if (ssh->sccomp->text_name)
7327 logeventf(ssh, "Initialised %s decompression",
7328 ssh->sccomp->text_name);
7331 * Free shared secret.
7336 * Key exchange is over. Loop straight back round if we have a
7337 * deferred rekey reason.
7339 if (ssh->deferred_rekey_reason) {
7340 logevent(ssh->deferred_rekey_reason);
7342 ssh->deferred_rekey_reason = NULL;
7343 goto begin_key_exchange;
7347 * Otherwise, schedule a timer for our next rekey.
7349 ssh->kex_in_progress = FALSE;
7350 ssh->last_rekey = GETTICKCOUNT();
7351 if (conf_get_int(ssh->conf, CONF_ssh_rekey_time) != 0)
7352 ssh->next_rekey = schedule_timer(conf_get_int(ssh->conf, CONF_ssh_rekey_time)*60*TICKSPERSEC,
7356 * Now we're encrypting. Begin returning 1 to the protocol main
7357 * function so that other things can run on top of the
7358 * transport. If we ever see a KEXINIT, we must go back to the
7361 * We _also_ go back to the start if we see pktin==NULL and
7362 * inlen negative, because this is a special signal meaning
7363 * `initiate client-driven rekey', and `in' contains a message
7364 * giving the reason for the rekey.
7366 * inlen==-1 means always initiate a rekey;
7367 * inlen==-2 means that userauth has completed successfully and
7368 * we should consider rekeying (for delayed compression).
7370 while (!((pktin && pktin->type == SSH2_MSG_KEXINIT) ||
7371 (!pktin && inlen < 0))) {
7373 if (!ssh->protocol_initial_phase_done) {
7374 ssh->protocol_initial_phase_done = TRUE;
7376 * Allow authconn to initialise itself.
7378 do_ssh2_authconn(ssh, NULL, 0, NULL);
7383 logevent("Server initiated key re-exchange");
7387 * authconn has seen a USERAUTH_SUCCEEDED. Time to enable
7388 * delayed compression, if it's available.
7390 * draft-miller-secsh-compression-delayed-00 says that you
7391 * negotiate delayed compression in the first key exchange, and
7392 * both sides start compressing when the server has sent
7393 * USERAUTH_SUCCESS. This has a race condition -- the server
7394 * can't know when the client has seen it, and thus which incoming
7395 * packets it should treat as compressed.
7397 * Instead, we do the initial key exchange without offering the
7398 * delayed methods, but note if the server offers them; when we
7399 * get here, if a delayed method was available that was higher
7400 * on our list than what we got, we initiate a rekey in which we
7401 * _do_ list the delayed methods (and hopefully get it as a
7402 * result). Subsequent rekeys will do the same.
7404 assert(!s->userauth_succeeded); /* should only happen once */
7405 s->userauth_succeeded = TRUE;
7406 if (!s->pending_compression)
7407 /* Can't see any point rekeying. */
7408 goto wait_for_rekey; /* this is utterly horrid */
7409 /* else fall through to rekey... */
7410 s->pending_compression = FALSE;
7413 * Now we've decided to rekey.
7415 * Special case: if the server bug is set that doesn't
7416 * allow rekeying, we give a different log message and
7417 * continue waiting. (If such a server _initiates_ a rekey,
7418 * we process it anyway!)
7420 if ((ssh->remote_bugs & BUG_SSH2_REKEY)) {
7421 logeventf(ssh, "Server bug prevents key re-exchange (%s)",
7423 /* Reset the counters, so that at least this message doesn't
7424 * hit the event log _too_ often. */
7425 ssh->outgoing_data_size = 0;
7426 ssh->incoming_data_size = 0;
7427 if (conf_get_int(ssh->conf, CONF_ssh_rekey_time) != 0) {
7429 schedule_timer(conf_get_int(ssh->conf, CONF_ssh_rekey_time)*60*TICKSPERSEC,
7432 goto wait_for_rekey; /* this is still utterly horrid */
7434 logeventf(ssh, "Initiating key re-exchange (%s)", (char *)in);
7437 goto begin_key_exchange;
7443 * Add data to an SSH-2 channel output buffer.
7445 static void ssh2_add_channel_data(struct ssh_channel *c, const char *buf,
7448 bufchain_add(&c->v.v2.outbuffer, buf, len);
7452 * Attempt to send data on an SSH-2 channel.
7454 static int ssh2_try_send(struct ssh_channel *c)
7457 struct Packet *pktout;
7460 while (c->v.v2.remwindow > 0 && bufchain_size(&c->v.v2.outbuffer) > 0) {
7463 bufchain_prefix(&c->v.v2.outbuffer, &data, &len);
7464 if ((unsigned)len > c->v.v2.remwindow)
7465 len = c->v.v2.remwindow;
7466 if ((unsigned)len > c->v.v2.remmaxpkt)
7467 len = c->v.v2.remmaxpkt;
7468 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_DATA);
7469 ssh2_pkt_adduint32(pktout, c->remoteid);
7470 ssh2_pkt_addstring_start(pktout);
7471 ssh2_pkt_addstring_data(pktout, data, len);
7472 ssh2_pkt_send(ssh, pktout);
7473 bufchain_consume(&c->v.v2.outbuffer, len);
7474 c->v.v2.remwindow -= len;
7478 * After having sent as much data as we can, return the amount
7481 ret = bufchain_size(&c->v.v2.outbuffer);
7484 * And if there's no data pending but we need to send an EOF, send
7487 if (!ret && c->pending_eof)
7488 ssh_channel_try_eof(c);
7493 static void ssh2_try_send_and_unthrottle(Ssh ssh, struct ssh_channel *c)
7496 if (c->closes & CLOSES_SENT_EOF)
7497 return; /* don't send on channels we've EOFed */
7498 bufsize = ssh2_try_send(c);
7501 case CHAN_MAINSESSION:
7502 /* stdin need not receive an unthrottle
7503 * notification since it will be polled */
7506 x11_unthrottle(c->u.x11.xconn);
7509 /* agent sockets are request/response and need no
7510 * buffer management */
7513 pfd_unthrottle(c->u.pfd.pf);
7519 static int ssh_is_simple(Ssh ssh)
7522 * We use the 'simple' variant of the SSH protocol if we're asked
7523 * to, except not if we're also doing connection-sharing (either
7524 * tunnelling our packets over an upstream or expecting to be
7525 * tunnelled over ourselves), since then the assumption that we
7526 * have only one channel to worry about is not true after all.
7528 return (conf_get_int(ssh->conf, CONF_ssh_simple) &&
7529 !ssh->bare_connection && !ssh->connshare);
7533 * Set up most of a new ssh_channel for SSH-2.
7535 static void ssh2_channel_init(struct ssh_channel *c)
7538 c->localid = alloc_channel_id(ssh);
7540 c->pending_eof = FALSE;
7541 c->throttling_conn = FALSE;
7542 c->v.v2.locwindow = c->v.v2.locmaxwin = c->v.v2.remlocwin =
7543 ssh_is_simple(ssh) ? OUR_V2_BIGWIN : OUR_V2_WINSIZE;
7544 c->v.v2.chanreq_head = NULL;
7545 c->v.v2.throttle_state = UNTHROTTLED;
7546 bufchain_init(&c->v.v2.outbuffer);
7550 * Construct the common parts of a CHANNEL_OPEN.
7552 static struct Packet *ssh2_chanopen_init(struct ssh_channel *c,
7555 struct Packet *pktout;
7557 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN);
7558 ssh2_pkt_addstring(pktout, type);
7559 ssh2_pkt_adduint32(pktout, c->localid);
7560 ssh2_pkt_adduint32(pktout, c->v.v2.locwindow);/* our window size */
7561 ssh2_pkt_adduint32(pktout, OUR_V2_MAXPKT); /* our max pkt size */
7566 * CHANNEL_FAILURE doesn't come with any indication of what message
7567 * caused it, so we have to keep track of the outstanding
7568 * CHANNEL_REQUESTs ourselves.
7570 static void ssh2_queue_chanreq_handler(struct ssh_channel *c,
7571 cchandler_fn_t handler, void *ctx)
7573 struct outstanding_channel_request *ocr =
7574 snew(struct outstanding_channel_request);
7576 assert(!(c->closes & (CLOSES_SENT_CLOSE | CLOSES_RCVD_CLOSE)));
7577 ocr->handler = handler;
7580 if (!c->v.v2.chanreq_head)
7581 c->v.v2.chanreq_head = ocr;
7583 c->v.v2.chanreq_tail->next = ocr;
7584 c->v.v2.chanreq_tail = ocr;
7588 * Construct the common parts of a CHANNEL_REQUEST. If handler is not
7589 * NULL then a reply will be requested and the handler will be called
7590 * when it arrives. The returned packet is ready to have any
7591 * request-specific data added and be sent. Note that if a handler is
7592 * provided, it's essential that the request actually be sent.
7594 * The handler will usually be passed the response packet in pktin. If
7595 * pktin is NULL, this means that no reply will ever be forthcoming
7596 * (e.g. because the entire connection is being destroyed, or because
7597 * the server initiated channel closure before we saw the response)
7598 * and the handler should free any storage it's holding.
7600 static struct Packet *ssh2_chanreq_init(struct ssh_channel *c,
7602 cchandler_fn_t handler, void *ctx)
7604 struct Packet *pktout;
7606 assert(!(c->closes & (CLOSES_SENT_CLOSE | CLOSES_RCVD_CLOSE)));
7607 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
7608 ssh2_pkt_adduint32(pktout, c->remoteid);
7609 ssh2_pkt_addstring(pktout, type);
7610 ssh2_pkt_addbool(pktout, handler != NULL);
7611 if (handler != NULL)
7612 ssh2_queue_chanreq_handler(c, handler, ctx);
7617 * Potentially enlarge the window on an SSH-2 channel.
7619 static void ssh2_handle_winadj_response(struct ssh_channel *, struct Packet *,
7621 static void ssh2_set_window(struct ssh_channel *c, int newwin)
7626 * Never send WINDOW_ADJUST for a channel that the remote side has
7627 * already sent EOF on; there's no point, since it won't be
7628 * sending any more data anyway. Ditto if _we've_ already sent
7631 if (c->closes & (CLOSES_RCVD_EOF | CLOSES_SENT_CLOSE))
7635 * Also, never widen the window for an X11 channel when we're
7636 * still waiting to see its initial auth and may yet hand it off
7639 if (c->type == CHAN_X11 && c->u.x11.initial)
7643 * If the remote end has a habit of ignoring maxpkt, limit the
7644 * window so that it has no choice (assuming it doesn't ignore the
7647 if ((ssh->remote_bugs & BUG_SSH2_MAXPKT) && newwin > OUR_V2_MAXPKT)
7648 newwin = OUR_V2_MAXPKT;
7651 * Only send a WINDOW_ADJUST if there's significantly more window
7652 * available than the other end thinks there is. This saves us
7653 * sending a WINDOW_ADJUST for every character in a shell session.
7655 * "Significant" is arbitrarily defined as half the window size.
7657 if (newwin / 2 >= c->v.v2.locwindow) {
7658 struct Packet *pktout;
7662 * In order to keep track of how much window the client
7663 * actually has available, we'd like it to acknowledge each
7664 * WINDOW_ADJUST. We can't do that directly, so we accompany
7665 * it with a CHANNEL_REQUEST that has to be acknowledged.
7667 * This is only necessary if we're opening the window wide.
7668 * If we're not, then throughput is being constrained by
7669 * something other than the maximum window size anyway.
7671 if (newwin == c->v.v2.locmaxwin &&
7672 !(ssh->remote_bugs & BUG_CHOKES_ON_WINADJ)) {
7673 up = snew(unsigned);
7674 *up = newwin - c->v.v2.locwindow;
7675 pktout = ssh2_chanreq_init(c, "winadj@putty.projects.tartarus.org",
7676 ssh2_handle_winadj_response, up);
7677 ssh2_pkt_send(ssh, pktout);
7679 if (c->v.v2.throttle_state != UNTHROTTLED)
7680 c->v.v2.throttle_state = UNTHROTTLING;
7682 /* Pretend the WINDOW_ADJUST was acked immediately. */
7683 c->v.v2.remlocwin = newwin;
7684 c->v.v2.throttle_state = THROTTLED;
7686 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
7687 ssh2_pkt_adduint32(pktout, c->remoteid);
7688 ssh2_pkt_adduint32(pktout, newwin - c->v.v2.locwindow);
7689 ssh2_pkt_send(ssh, pktout);
7690 c->v.v2.locwindow = newwin;
7695 * Find the channel associated with a message. If there's no channel,
7696 * or it's not properly open, make a noise about it and return NULL.
7698 static struct ssh_channel *ssh2_channel_msg(Ssh ssh, struct Packet *pktin)
7700 unsigned localid = ssh_pkt_getuint32(pktin);
7701 struct ssh_channel *c;
7703 c = find234(ssh->channels, &localid, ssh_channelfind);
7705 (c->type != CHAN_SHARING && c->halfopen &&
7706 pktin->type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION &&
7707 pktin->type != SSH2_MSG_CHANNEL_OPEN_FAILURE)) {
7708 char *buf = dupprintf("Received %s for %s channel %u",
7709 ssh2_pkt_type(ssh->pkt_kctx, ssh->pkt_actx,
7711 c ? "half-open" : "nonexistent", localid);
7712 ssh_disconnect(ssh, NULL, buf, SSH2_DISCONNECT_PROTOCOL_ERROR, FALSE);
7719 static void ssh2_handle_winadj_response(struct ssh_channel *c,
7720 struct Packet *pktin, void *ctx)
7722 unsigned *sizep = ctx;
7725 * Winadj responses should always be failures. However, at least
7726 * one server ("boks_sshd") is known to return SUCCESS for channel
7727 * requests it's never heard of, such as "winadj@putty". Raised
7728 * with foxt.com as bug 090916-090424, but for the sake of a quiet
7729 * life, we don't worry about what kind of response we got.
7732 c->v.v2.remlocwin += *sizep;
7735 * winadj messages are only sent when the window is fully open, so
7736 * if we get an ack of one, we know any pending unthrottle is
7739 if (c->v.v2.throttle_state == UNTHROTTLING)
7740 c->v.v2.throttle_state = UNTHROTTLED;
7743 static void ssh2_msg_channel_response(Ssh ssh, struct Packet *pktin)
7745 struct ssh_channel *c = ssh2_channel_msg(ssh, pktin);
7746 struct outstanding_channel_request *ocr;
7749 if (c->type == CHAN_SHARING) {
7750 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
7751 pktin->body, pktin->length);
7754 ocr = c->v.v2.chanreq_head;
7756 ssh2_msg_unexpected(ssh, pktin);
7759 ocr->handler(c, pktin, ocr->ctx);
7760 c->v.v2.chanreq_head = ocr->next;
7763 * We may now initiate channel-closing procedures, if that
7764 * CHANNEL_REQUEST was the last thing outstanding before we send
7767 ssh2_channel_check_close(c);
7770 static void ssh2_msg_channel_window_adjust(Ssh ssh, struct Packet *pktin)
7772 struct ssh_channel *c;
7773 c = ssh2_channel_msg(ssh, pktin);
7776 if (c->type == CHAN_SHARING) {
7777 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
7778 pktin->body, pktin->length);
7781 if (!(c->closes & CLOSES_SENT_EOF)) {
7782 c->v.v2.remwindow += ssh_pkt_getuint32(pktin);
7783 ssh2_try_send_and_unthrottle(ssh, c);
7787 static void ssh2_msg_channel_data(Ssh ssh, struct Packet *pktin)
7791 struct ssh_channel *c;
7792 c = ssh2_channel_msg(ssh, pktin);
7795 if (c->type == CHAN_SHARING) {
7796 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
7797 pktin->body, pktin->length);
7800 if (pktin->type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
7801 ssh_pkt_getuint32(pktin) != SSH2_EXTENDED_DATA_STDERR)
7802 return; /* extended but not stderr */
7803 ssh_pkt_getstring(pktin, &data, &length);
7806 c->v.v2.locwindow -= length;
7807 c->v.v2.remlocwin -= length;
7809 case CHAN_MAINSESSION:
7811 from_backend(ssh->frontend, pktin->type ==
7812 SSH2_MSG_CHANNEL_EXTENDED_DATA,
7816 bufsize = x11_send(c->u.x11.xconn, data, length);
7819 bufsize = pfd_send(c->u.pfd.pf, data, length);
7822 while (length > 0) {
7823 if (c->u.a.lensofar < 4) {
7824 unsigned int l = min(4 - c->u.a.lensofar,
7826 memcpy(c->u.a.msglen + c->u.a.lensofar,
7830 c->u.a.lensofar += l;
7832 if (c->u.a.lensofar == 4) {
7834 4 + GET_32BIT(c->u.a.msglen);
7835 c->u.a.message = snewn(c->u.a.totallen,
7837 memcpy(c->u.a.message, c->u.a.msglen, 4);
7839 if (c->u.a.lensofar >= 4 && length > 0) {
7841 min(c->u.a.totallen - c->u.a.lensofar,
7843 memcpy(c->u.a.message + c->u.a.lensofar,
7847 c->u.a.lensofar += l;
7849 if (c->u.a.lensofar == c->u.a.totallen) {
7852 c->u.a.outstanding_requests++;
7853 if (agent_query(c->u.a.message,
7856 ssh_agentf_callback, c))
7857 ssh_agentf_callback(c, reply, replylen);
7858 sfree(c->u.a.message);
7859 c->u.a.message = NULL;
7860 c->u.a.lensofar = 0;
7867 * If it looks like the remote end hit the end of its window,
7868 * and we didn't want it to do that, think about using a
7871 if (c->v.v2.remlocwin <= 0 && c->v.v2.throttle_state == UNTHROTTLED &&
7872 c->v.v2.locmaxwin < 0x40000000)
7873 c->v.v2.locmaxwin += OUR_V2_WINSIZE;
7875 * If we are not buffering too much data,
7876 * enlarge the window again at the remote side.
7877 * If we are buffering too much, we may still
7878 * need to adjust the window if the server's
7881 ssh2_set_window(c, bufsize < c->v.v2.locmaxwin ?
7882 c->v.v2.locmaxwin - bufsize : 0);
7884 * If we're either buffering way too much data, or if we're
7885 * buffering anything at all and we're in "simple" mode,
7886 * throttle the whole channel.
7888 if ((bufsize > c->v.v2.locmaxwin || (ssh_is_simple(ssh) && bufsize>0))
7889 && !c->throttling_conn) {
7890 c->throttling_conn = 1;
7891 ssh_throttle_conn(ssh, +1);
7896 static void ssh_check_termination(Ssh ssh)
7898 if (ssh->version == 2 &&
7899 !conf_get_int(ssh->conf, CONF_ssh_no_shell) &&
7900 (ssh->channels && count234(ssh->channels) == 0) &&
7901 !(ssh->connshare && share_ndownstreams(ssh->connshare) > 0)) {
7903 * We used to send SSH_MSG_DISCONNECT here, because I'd
7904 * believed that _every_ conforming SSH-2 connection had to
7905 * end with a disconnect being sent by at least one side;
7906 * apparently I was wrong and it's perfectly OK to
7907 * unceremoniously slam the connection shut when you're done,
7908 * and indeed OpenSSH feels this is more polite than sending a
7909 * DISCONNECT. So now we don't.
7911 ssh_disconnect(ssh, "All channels closed", NULL, 0, TRUE);
7915 void ssh_sharing_downstream_connected(Ssh ssh, unsigned id,
7916 const char *peerinfo)
7919 logeventf(ssh, "Connection sharing downstream #%u connected from %s",
7922 logeventf(ssh, "Connection sharing downstream #%u connected", id);
7925 void ssh_sharing_downstream_disconnected(Ssh ssh, unsigned id)
7927 logeventf(ssh, "Connection sharing downstream #%u disconnected", id);
7928 ssh_check_termination(ssh);
7931 void ssh_sharing_logf(Ssh ssh, unsigned id, const char *logfmt, ...)
7936 va_start(ap, logfmt);
7937 buf = dupvprintf(logfmt, ap);
7940 logeventf(ssh, "Connection sharing downstream #%u: %s", id, buf);
7942 logeventf(ssh, "Connection sharing: %s", buf);
7946 static void ssh_channel_destroy(struct ssh_channel *c)
7951 case CHAN_MAINSESSION:
7952 ssh->mainchan = NULL;
7953 update_specials_menu(ssh->frontend);
7956 if (c->u.x11.xconn != NULL)
7957 x11_close(c->u.x11.xconn);
7958 logevent("Forwarded X11 connection terminated");
7961 sfree(c->u.a.message);
7964 if (c->u.pfd.pf != NULL)
7965 pfd_close(c->u.pfd.pf);
7966 logevent("Forwarded port closed");
7970 del234(ssh->channels, c);
7971 if (ssh->version == 2) {
7972 bufchain_clear(&c->v.v2.outbuffer);
7973 assert(c->v.v2.chanreq_head == NULL);
7978 * If that was the last channel left open, we might need to
7981 ssh_check_termination(ssh);
7984 static void ssh2_channel_check_close(struct ssh_channel *c)
7987 struct Packet *pktout;
7991 * If we've sent out our own CHANNEL_OPEN but not yet seen
7992 * either OPEN_CONFIRMATION or OPEN_FAILURE in response, then
7993 * it's too early to be sending close messages of any kind.
7998 if ((!((CLOSES_SENT_EOF | CLOSES_RCVD_EOF) & ~c->closes) ||
7999 c->type == CHAN_ZOMBIE) &&
8000 !c->v.v2.chanreq_head &&
8001 !(c->closes & CLOSES_SENT_CLOSE)) {
8003 * We have both sent and received EOF (or the channel is a
8004 * zombie), and we have no outstanding channel requests, which
8005 * means the channel is in final wind-up. But we haven't sent
8006 * CLOSE, so let's do so now.
8008 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE);
8009 ssh2_pkt_adduint32(pktout, c->remoteid);
8010 ssh2_pkt_send(ssh, pktout);
8011 c->closes |= CLOSES_SENT_EOF | CLOSES_SENT_CLOSE;
8014 if (!((CLOSES_SENT_CLOSE | CLOSES_RCVD_CLOSE) & ~c->closes)) {
8015 assert(c->v.v2.chanreq_head == NULL);
8017 * We have both sent and received CLOSE, which means we're
8018 * completely done with the channel.
8020 ssh_channel_destroy(c);
8024 static void ssh2_channel_got_eof(struct ssh_channel *c)
8026 if (c->closes & CLOSES_RCVD_EOF)
8027 return; /* already seen EOF */
8028 c->closes |= CLOSES_RCVD_EOF;
8030 if (c->type == CHAN_X11) {
8031 x11_send_eof(c->u.x11.xconn);
8032 } else if (c->type == CHAN_AGENT) {
8033 if (c->u.a.outstanding_requests == 0) {
8034 /* Manufacture an outgoing EOF in response to the incoming one. */
8035 sshfwd_write_eof(c);
8037 } else if (c->type == CHAN_SOCKDATA) {
8038 pfd_send_eof(c->u.pfd.pf);
8039 } else if (c->type == CHAN_MAINSESSION) {
8042 if (!ssh->sent_console_eof &&
8043 (from_backend_eof(ssh->frontend) || ssh->got_pty)) {
8045 * Either from_backend_eof told us that the front end
8046 * wants us to close the outgoing side of the connection
8047 * as soon as we see EOF from the far end, or else we've
8048 * unilaterally decided to do that because we've allocated
8049 * a remote pty and hence EOF isn't a particularly
8050 * meaningful concept.
8052 sshfwd_write_eof(c);
8054 ssh->sent_console_eof = TRUE;
8057 ssh2_channel_check_close(c);
8060 static void ssh2_msg_channel_eof(Ssh ssh, struct Packet *pktin)
8062 struct ssh_channel *c;
8064 c = ssh2_channel_msg(ssh, pktin);
8067 if (c->type == CHAN_SHARING) {
8068 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
8069 pktin->body, pktin->length);
8072 ssh2_channel_got_eof(c);
8075 static void ssh2_msg_channel_close(Ssh ssh, struct Packet *pktin)
8077 struct ssh_channel *c;
8079 c = ssh2_channel_msg(ssh, pktin);
8082 if (c->type == CHAN_SHARING) {
8083 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
8084 pktin->body, pktin->length);
8089 * When we receive CLOSE on a channel, we assume it comes with an
8090 * implied EOF if we haven't seen EOF yet.
8092 ssh2_channel_got_eof(c);
8094 if (!(ssh->remote_bugs & BUG_SENDS_LATE_REQUEST_REPLY)) {
8096 * It also means we stop expecting to see replies to any
8097 * outstanding channel requests, so clean those up too.
8098 * (ssh_chanreq_init will enforce by assertion that we don't
8099 * subsequently put anything back on this list.)
8101 while (c->v.v2.chanreq_head) {
8102 struct outstanding_channel_request *ocr = c->v.v2.chanreq_head;
8103 ocr->handler(c, NULL, ocr->ctx);
8104 c->v.v2.chanreq_head = ocr->next;
8110 * And we also send an outgoing EOF, if we haven't already, on the
8111 * assumption that CLOSE is a pretty forceful announcement that
8112 * the remote side is doing away with the entire channel. (If it
8113 * had wanted to send us EOF and continue receiving data from us,
8114 * it would have just sent CHANNEL_EOF.)
8116 if (!(c->closes & CLOSES_SENT_EOF)) {
8118 * Make sure we don't read any more from whatever our local
8119 * data source is for this channel.
8122 case CHAN_MAINSESSION:
8123 ssh->send_ok = 0; /* stop trying to read from stdin */
8126 x11_override_throttle(c->u.x11.xconn, 1);
8129 pfd_override_throttle(c->u.pfd.pf, 1);
8134 * Abandon any buffered data we still wanted to send to this
8135 * channel. Receiving a CHANNEL_CLOSE is an indication that
8136 * the server really wants to get on and _destroy_ this
8137 * channel, and it isn't going to send us any further
8138 * WINDOW_ADJUSTs to permit us to send pending stuff.
8140 bufchain_clear(&c->v.v2.outbuffer);
8143 * Send outgoing EOF.
8145 sshfwd_write_eof(c);
8149 * Now process the actual close.
8151 if (!(c->closes & CLOSES_RCVD_CLOSE)) {
8152 c->closes |= CLOSES_RCVD_CLOSE;
8153 ssh2_channel_check_close(c);
8157 static void ssh2_msg_channel_open_confirmation(Ssh ssh, struct Packet *pktin)
8159 struct ssh_channel *c;
8161 c = ssh2_channel_msg(ssh, pktin);
8164 if (c->type == CHAN_SHARING) {
8165 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
8166 pktin->body, pktin->length);
8169 assert(c->halfopen); /* ssh2_channel_msg will have enforced this */
8170 c->remoteid = ssh_pkt_getuint32(pktin);
8171 c->halfopen = FALSE;
8172 c->v.v2.remwindow = ssh_pkt_getuint32(pktin);
8173 c->v.v2.remmaxpkt = ssh_pkt_getuint32(pktin);
8175 if (c->type == CHAN_SOCKDATA_DORMANT) {
8176 c->type = CHAN_SOCKDATA;
8178 pfd_confirm(c->u.pfd.pf);
8179 } else if (c->type == CHAN_ZOMBIE) {
8181 * This case can occur if a local socket error occurred
8182 * between us sending out CHANNEL_OPEN and receiving
8183 * OPEN_CONFIRMATION. In this case, all we can do is
8184 * immediately initiate close proceedings now that we know the
8185 * server's id to put in the close message.
8187 ssh2_channel_check_close(c);
8190 * We never expect to receive OPEN_CONFIRMATION for any
8191 * *other* channel type (since only local-to-remote port
8192 * forwardings cause us to send CHANNEL_OPEN after the main
8193 * channel is live - all other auxiliary channel types are
8194 * initiated from the server end). It's safe to enforce this
8195 * by assertion rather than by ssh_disconnect, because the
8196 * real point is that we never constructed a half-open channel
8197 * structure in the first place with any type other than the
8200 assert(!"Funny channel type in ssh2_msg_channel_open_confirmation");
8204 ssh_channel_try_eof(c); /* in case we had a pending EOF */
8207 static void ssh2_msg_channel_open_failure(Ssh ssh, struct Packet *pktin)
8209 static const char *const reasons[] = {
8210 "<unknown reason code>",
8211 "Administratively prohibited",
8213 "Unknown channel type",
8214 "Resource shortage",
8216 unsigned reason_code;
8217 char *reason_string;
8219 struct ssh_channel *c;
8221 c = ssh2_channel_msg(ssh, pktin);
8224 if (c->type == CHAN_SHARING) {
8225 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
8226 pktin->body, pktin->length);
8229 assert(c->halfopen); /* ssh2_channel_msg will have enforced this */
8231 if (c->type == CHAN_SOCKDATA_DORMANT) {
8232 reason_code = ssh_pkt_getuint32(pktin);
8233 if (reason_code >= lenof(reasons))
8234 reason_code = 0; /* ensure reasons[reason_code] in range */
8235 ssh_pkt_getstring(pktin, &reason_string, &reason_length);
8236 logeventf(ssh, "Forwarded connection refused by server: %s [%.*s]",
8237 reasons[reason_code], reason_length, reason_string);
8239 pfd_close(c->u.pfd.pf);
8240 } else if (c->type == CHAN_ZOMBIE) {
8242 * This case can occur if a local socket error occurred
8243 * between us sending out CHANNEL_OPEN and receiving
8244 * OPEN_FAILURE. In this case, we need do nothing except allow
8245 * the code below to throw the half-open channel away.
8249 * We never expect to receive OPEN_FAILURE for any *other*
8250 * channel type (since only local-to-remote port forwardings
8251 * cause us to send CHANNEL_OPEN after the main channel is
8252 * live - all other auxiliary channel types are initiated from
8253 * the server end). It's safe to enforce this by assertion
8254 * rather than by ssh_disconnect, because the real point is
8255 * that we never constructed a half-open channel structure in
8256 * the first place with any type other than the above.
8258 assert(!"Funny channel type in ssh2_msg_channel_open_failure");
8261 del234(ssh->channels, c);
8265 static void ssh2_msg_channel_request(Ssh ssh, struct Packet *pktin)
8268 int typelen, want_reply;
8269 int reply = SSH2_MSG_CHANNEL_FAILURE; /* default */
8270 struct ssh_channel *c;
8271 struct Packet *pktout;
8273 c = ssh2_channel_msg(ssh, pktin);
8276 if (c->type == CHAN_SHARING) {
8277 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
8278 pktin->body, pktin->length);
8281 ssh_pkt_getstring(pktin, &type, &typelen);
8282 want_reply = ssh2_pkt_getbool(pktin);
8284 if (c->closes & CLOSES_SENT_CLOSE) {
8286 * We don't reply to channel requests after we've sent
8287 * CHANNEL_CLOSE for the channel, because our reply might
8288 * cross in the network with the other side's CHANNEL_CLOSE
8289 * and arrive after they have wound the channel up completely.
8295 * Having got the channel number, we now look at
8296 * the request type string to see if it's something
8299 if (c == ssh->mainchan) {
8301 * We recognise "exit-status" and "exit-signal" on
8302 * the primary channel.
8304 if (typelen == 11 &&
8305 !memcmp(type, "exit-status", 11)) {
8307 ssh->exitcode = ssh_pkt_getuint32(pktin);
8308 logeventf(ssh, "Server sent command exit status %d",
8310 reply = SSH2_MSG_CHANNEL_SUCCESS;
8312 } else if (typelen == 11 &&
8313 !memcmp(type, "exit-signal", 11)) {
8315 int is_plausible = TRUE, is_int = FALSE;
8316 char *fmt_sig = NULL, *fmt_msg = NULL;
8318 int msglen = 0, core = FALSE;
8319 /* ICK: older versions of OpenSSH (e.g. 3.4p1)
8320 * provide an `int' for the signal, despite its
8321 * having been a `string' in the drafts of RFC 4254 since at
8322 * least 2001. (Fixed in session.c 1.147.) Try to
8323 * infer which we can safely parse it as. */
8325 unsigned char *p = pktin->body +
8327 long len = pktin->length - pktin->savedpos;
8328 unsigned long num = GET_32BIT(p); /* what is it? */
8329 /* If it's 0, it hardly matters; assume string */
8333 int maybe_int = FALSE, maybe_str = FALSE;
8334 #define CHECK_HYPOTHESIS(offset, result) \
8337 int q = toint(offset); \
8338 if (q >= 0 && q+4 <= len) { \
8339 q = toint(q + 4 + GET_32BIT(p+q)); \
8340 if (q >= 0 && q+4 <= len && \
8341 ((q = toint(q + 4 + GET_32BIT(p+q))) != 0) && \
8346 CHECK_HYPOTHESIS(4+1, maybe_int);
8347 CHECK_HYPOTHESIS(4+num+1, maybe_str);
8348 #undef CHECK_HYPOTHESIS
8349 if (maybe_int && !maybe_str)
8351 else if (!maybe_int && maybe_str)
8354 /* Crikey. Either or neither. Panic. */
8355 is_plausible = FALSE;
8358 ssh->exitcode = 128; /* means `unknown signal' */
8361 /* Old non-standard OpenSSH. */
8362 int signum = ssh_pkt_getuint32(pktin);
8363 fmt_sig = dupprintf(" %d", signum);
8364 ssh->exitcode = 128 + signum;
8366 /* As per RFC 4254. */
8369 ssh_pkt_getstring(pktin, &sig, &siglen);
8370 /* Signal name isn't supposed to be blank, but
8371 * let's cope gracefully if it is. */
8373 fmt_sig = dupprintf(" \"%.*s\"",
8378 * Really hideous method of translating the
8379 * signal description back into a locally
8380 * meaningful number.
8385 #define TRANSLATE_SIGNAL(s) \
8386 else if (siglen == lenof(#s)-1 && !memcmp(sig, #s, siglen)) \
8387 ssh->exitcode = 128 + SIG ## s
8389 TRANSLATE_SIGNAL(ABRT);
8392 TRANSLATE_SIGNAL(ALRM);
8395 TRANSLATE_SIGNAL(FPE);
8398 TRANSLATE_SIGNAL(HUP);
8401 TRANSLATE_SIGNAL(ILL);
8404 TRANSLATE_SIGNAL(INT);
8407 TRANSLATE_SIGNAL(KILL);
8410 TRANSLATE_SIGNAL(PIPE);
8413 TRANSLATE_SIGNAL(QUIT);
8416 TRANSLATE_SIGNAL(SEGV);
8419 TRANSLATE_SIGNAL(TERM);
8422 TRANSLATE_SIGNAL(USR1);
8425 TRANSLATE_SIGNAL(USR2);
8427 #undef TRANSLATE_SIGNAL
8429 ssh->exitcode = 128;
8431 core = ssh2_pkt_getbool(pktin);
8432 ssh_pkt_getstring(pktin, &msg, &msglen);
8434 fmt_msg = dupprintf(" (\"%.*s\")", msglen, msg);
8436 /* ignore lang tag */
8437 } /* else don't attempt to parse */
8438 logeventf(ssh, "Server exited on signal%s%s%s",
8439 fmt_sig ? fmt_sig : "",
8440 core ? " (core dumped)" : "",
8441 fmt_msg ? fmt_msg : "");
8444 reply = SSH2_MSG_CHANNEL_SUCCESS;
8449 * This is a channel request we don't know
8450 * about, so we now either ignore the request
8451 * or respond with CHANNEL_FAILURE, depending
8454 reply = SSH2_MSG_CHANNEL_FAILURE;
8457 pktout = ssh2_pkt_init(reply);
8458 ssh2_pkt_adduint32(pktout, c->remoteid);
8459 ssh2_pkt_send(ssh, pktout);
8463 static void ssh2_msg_global_request(Ssh ssh, struct Packet *pktin)
8466 int typelen, want_reply;
8467 struct Packet *pktout;
8469 ssh_pkt_getstring(pktin, &type, &typelen);
8470 want_reply = ssh2_pkt_getbool(pktin);
8473 * We currently don't support any global requests
8474 * at all, so we either ignore the request or
8475 * respond with REQUEST_FAILURE, depending on
8479 pktout = ssh2_pkt_init(SSH2_MSG_REQUEST_FAILURE);
8480 ssh2_pkt_send(ssh, pktout);
8484 struct X11FakeAuth *ssh_sharing_add_x11_display(Ssh ssh, int authtype,
8488 struct X11FakeAuth *auth;
8491 * Make up a new set of fake X11 auth data, and add it to the tree
8492 * of currently valid ones with an indication of the sharing
8493 * context that it's relevant to.
8495 auth = x11_invent_fake_auth(ssh->x11authtree, authtype);
8496 auth->share_cs = share_cs;
8497 auth->share_chan = share_chan;
8502 void ssh_sharing_remove_x11_display(Ssh ssh, struct X11FakeAuth *auth)
8504 del234(ssh->x11authtree, auth);
8505 x11_free_fake_auth(auth);
8508 static void ssh2_msg_channel_open(Ssh ssh, struct Packet *pktin)
8515 const char *error = NULL;
8516 struct ssh_channel *c;
8517 unsigned remid, winsize, pktsize;
8518 unsigned our_winsize_override = 0;
8519 struct Packet *pktout;
8521 ssh_pkt_getstring(pktin, &type, &typelen);
8522 c = snew(struct ssh_channel);
8525 remid = ssh_pkt_getuint32(pktin);
8526 winsize = ssh_pkt_getuint32(pktin);
8527 pktsize = ssh_pkt_getuint32(pktin);
8529 if (typelen == 3 && !memcmp(type, "x11", 3)) {
8532 ssh_pkt_getstring(pktin, &peeraddr, &peeraddrlen);
8533 addrstr = snewn(peeraddrlen+1, char);
8534 memcpy(addrstr, peeraddr, peeraddrlen);
8535 addrstr[peeraddrlen] = '\0';
8536 peerport = ssh_pkt_getuint32(pktin);
8538 logeventf(ssh, "Received X11 connect request from %s:%d",
8541 if (!ssh->X11_fwd_enabled && !ssh->connshare)
8542 error = "X11 forwarding is not enabled";
8544 c->u.x11.xconn = x11_init(ssh->x11authtree, c,
8547 c->u.x11.initial = TRUE;
8550 * If we are a connection-sharing upstream, then we should
8551 * initially present a very small window, adequate to take
8552 * the X11 initial authorisation packet but not much more.
8553 * Downstream will then present us a larger window (by
8554 * fiat of the connection-sharing protocol) and we can
8555 * guarantee to send a positive-valued WINDOW_ADJUST.
8558 our_winsize_override = 128;
8560 logevent("Opened X11 forward channel");
8564 } else if (typelen == 15 &&
8565 !memcmp(type, "forwarded-tcpip", 15)) {
8566 struct ssh_rportfwd pf, *realpf;
8569 ssh_pkt_getstring(pktin, &shost, &shostlen);/* skip address */
8570 pf.shost = dupprintf("%.*s", shostlen, shost);
8571 pf.sport = ssh_pkt_getuint32(pktin);
8572 ssh_pkt_getstring(pktin, &peeraddr, &peeraddrlen);
8573 peerport = ssh_pkt_getuint32(pktin);
8574 realpf = find234(ssh->rportfwds, &pf, NULL);
8575 logeventf(ssh, "Received remote port %s:%d open request "
8576 "from %s:%d", pf.shost, pf.sport, peeraddr, peerport);
8579 if (realpf == NULL) {
8580 error = "Remote port is not recognised";
8584 if (realpf->share_ctx) {
8586 * This port forwarding is on behalf of a
8587 * connection-sharing downstream, so abandon our own
8588 * channel-open procedure and just pass the message on
8591 share_got_pkt_from_server(realpf->share_ctx, pktin->type,
8592 pktin->body, pktin->length);
8597 err = pfd_connect(&c->u.pfd.pf, realpf->dhost, realpf->dport,
8598 c, ssh->conf, realpf->pfrec->addressfamily);
8599 logeventf(ssh, "Attempting to forward remote port to "
8600 "%s:%d", realpf->dhost, realpf->dport);
8602 logeventf(ssh, "Port open failed: %s", err);
8604 error = "Port open failed";
8606 logevent("Forwarded port opened successfully");
8607 c->type = CHAN_SOCKDATA;
8610 } else if (typelen == 22 &&
8611 !memcmp(type, "auth-agent@openssh.com", 22)) {
8612 if (!ssh->agentfwd_enabled)
8613 error = "Agent forwarding is not enabled";
8615 c->type = CHAN_AGENT; /* identify channel type */
8616 c->u.a.lensofar = 0;
8617 c->u.a.message = NULL;
8618 c->u.a.outstanding_requests = 0;
8621 error = "Unsupported channel type requested";
8624 c->remoteid = remid;
8625 c->halfopen = FALSE;
8627 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_FAILURE);
8628 ssh2_pkt_adduint32(pktout, c->remoteid);
8629 ssh2_pkt_adduint32(pktout, SSH2_OPEN_CONNECT_FAILED);
8630 ssh2_pkt_addstring(pktout, error);
8631 ssh2_pkt_addstring(pktout, "en"); /* language tag */
8632 ssh2_pkt_send(ssh, pktout);
8633 logeventf(ssh, "Rejected channel open: %s", error);
8636 ssh2_channel_init(c);
8637 c->v.v2.remwindow = winsize;
8638 c->v.v2.remmaxpkt = pktsize;
8639 if (our_winsize_override) {
8640 c->v.v2.locwindow = c->v.v2.locmaxwin = c->v.v2.remlocwin =
8641 our_winsize_override;
8643 add234(ssh->channels, c);
8644 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
8645 ssh2_pkt_adduint32(pktout, c->remoteid);
8646 ssh2_pkt_adduint32(pktout, c->localid);
8647 ssh2_pkt_adduint32(pktout, c->v.v2.locwindow);
8648 ssh2_pkt_adduint32(pktout, OUR_V2_MAXPKT); /* our max pkt size */
8649 ssh2_pkt_send(ssh, pktout);
8653 void sshfwd_x11_sharing_handover(struct ssh_channel *c,
8654 void *share_cs, void *share_chan,
8655 const char *peer_addr, int peer_port,
8656 int endian, int protomajor, int protominor,
8657 const void *initial_data, int initial_len)
8660 * This function is called when we've just discovered that an X
8661 * forwarding channel on which we'd been handling the initial auth
8662 * ourselves turns out to be destined for a connection-sharing
8663 * downstream. So we turn the channel into a CHAN_SHARING, meaning
8664 * that we completely stop tracking windows and buffering data and
8665 * just pass more or less unmodified SSH messages back and forth.
8667 c->type = CHAN_SHARING;
8668 c->u.sharing.ctx = share_cs;
8669 share_setup_x11_channel(share_cs, share_chan,
8670 c->localid, c->remoteid, c->v.v2.remwindow,
8671 c->v.v2.remmaxpkt, c->v.v2.locwindow,
8672 peer_addr, peer_port, endian,
8673 protomajor, protominor,
8674 initial_data, initial_len);
8677 void sshfwd_x11_is_local(struct ssh_channel *c)
8680 * This function is called when we've just discovered that an X
8681 * forwarding channel is _not_ destined for a connection-sharing
8682 * downstream but we're going to handle it ourselves. We stop
8683 * presenting a cautiously small window and go into ordinary data
8686 c->u.x11.initial = FALSE;
8687 ssh2_set_window(c, ssh_is_simple(c->ssh) ? OUR_V2_BIGWIN : OUR_V2_WINSIZE);
8691 * Buffer banner messages for later display at some convenient point,
8692 * if we're going to display them.
8694 static void ssh2_msg_userauth_banner(Ssh ssh, struct Packet *pktin)
8696 /* Arbitrary limit to prevent unbounded inflation of buffer */
8697 if (conf_get_int(ssh->conf, CONF_ssh_show_banner) &&
8698 bufchain_size(&ssh->banner) <= 131072) {
8699 char *banner = NULL;
8701 ssh_pkt_getstring(pktin, &banner, &size);
8703 bufchain_add(&ssh->banner, banner, size);
8707 /* Helper function to deal with sending tty modes for "pty-req" */
8708 static void ssh2_send_ttymode(void *data, char *mode, char *val)
8710 struct Packet *pktout = (struct Packet *)data;
8712 unsigned int arg = 0;
8713 while (strcmp(mode, ssh_ttymodes[i].mode) != 0) i++;
8714 if (i == lenof(ssh_ttymodes)) return;
8715 switch (ssh_ttymodes[i].type) {
8717 arg = ssh_tty_parse_specchar(val);
8720 arg = ssh_tty_parse_boolean(val);
8723 ssh2_pkt_addbyte(pktout, ssh_ttymodes[i].opcode);
8724 ssh2_pkt_adduint32(pktout, arg);
8727 static void ssh2_setup_x11(struct ssh_channel *c, struct Packet *pktin,
8730 struct ssh2_setup_x11_state {
8734 struct Packet *pktout;
8735 crStateP(ssh2_setup_x11_state, ctx);
8739 logevent("Requesting X11 forwarding");
8740 pktout = ssh2_chanreq_init(ssh->mainchan, "x11-req",
8742 ssh2_pkt_addbool(pktout, 0); /* many connections */
8743 ssh2_pkt_addstring(pktout, ssh->x11auth->protoname);
8744 ssh2_pkt_addstring(pktout, ssh->x11auth->datastring);
8745 ssh2_pkt_adduint32(pktout, ssh->x11disp->screennum);
8746 ssh2_pkt_send(ssh, pktout);
8748 /* Wait to be called back with either a response packet, or NULL
8749 * meaning clean up and free our data */
8753 if (pktin->type == SSH2_MSG_CHANNEL_SUCCESS) {
8754 logevent("X11 forwarding enabled");
8755 ssh->X11_fwd_enabled = TRUE;
8757 logevent("X11 forwarding refused");
8763 static void ssh2_setup_agent(struct ssh_channel *c, struct Packet *pktin,
8766 struct ssh2_setup_agent_state {
8770 struct Packet *pktout;
8771 crStateP(ssh2_setup_agent_state, ctx);
8775 logevent("Requesting OpenSSH-style agent forwarding");
8776 pktout = ssh2_chanreq_init(ssh->mainchan, "auth-agent-req@openssh.com",
8777 ssh2_setup_agent, s);
8778 ssh2_pkt_send(ssh, pktout);
8780 /* Wait to be called back with either a response packet, or NULL
8781 * meaning clean up and free our data */
8785 if (pktin->type == SSH2_MSG_CHANNEL_SUCCESS) {
8786 logevent("Agent forwarding enabled");
8787 ssh->agentfwd_enabled = TRUE;
8789 logevent("Agent forwarding refused");
8795 static void ssh2_setup_pty(struct ssh_channel *c, struct Packet *pktin,
8798 struct ssh2_setup_pty_state {
8802 struct Packet *pktout;
8803 crStateP(ssh2_setup_pty_state, ctx);
8807 /* Unpick the terminal-speed string. */
8808 /* XXX perhaps we should allow no speeds to be sent. */
8809 ssh->ospeed = 38400; ssh->ispeed = 38400; /* last-resort defaults */
8810 sscanf(conf_get_str(ssh->conf, CONF_termspeed), "%d,%d", &ssh->ospeed, &ssh->ispeed);
8811 /* Build the pty request. */
8812 pktout = ssh2_chanreq_init(ssh->mainchan, "pty-req",
8814 ssh2_pkt_addstring(pktout, conf_get_str(ssh->conf, CONF_termtype));
8815 ssh2_pkt_adduint32(pktout, ssh->term_width);
8816 ssh2_pkt_adduint32(pktout, ssh->term_height);
8817 ssh2_pkt_adduint32(pktout, 0); /* pixel width */
8818 ssh2_pkt_adduint32(pktout, 0); /* pixel height */
8819 ssh2_pkt_addstring_start(pktout);
8820 parse_ttymodes(ssh, ssh2_send_ttymode, (void *)pktout);
8821 ssh2_pkt_addbyte(pktout, SSH2_TTY_OP_ISPEED);
8822 ssh2_pkt_adduint32(pktout, ssh->ispeed);
8823 ssh2_pkt_addbyte(pktout, SSH2_TTY_OP_OSPEED);
8824 ssh2_pkt_adduint32(pktout, ssh->ospeed);
8825 ssh2_pkt_addstring_data(pktout, "\0", 1); /* TTY_OP_END */
8826 ssh2_pkt_send(ssh, pktout);
8827 ssh->state = SSH_STATE_INTERMED;
8829 /* Wait to be called back with either a response packet, or NULL
8830 * meaning clean up and free our data */
8834 if (pktin->type == SSH2_MSG_CHANNEL_SUCCESS) {
8835 logeventf(ssh, "Allocated pty (ospeed %dbps, ispeed %dbps)",
8836 ssh->ospeed, ssh->ispeed);
8837 ssh->got_pty = TRUE;
8839 c_write_str(ssh, "Server refused to allocate pty\r\n");
8840 ssh->editing = ssh->echoing = 1;
8847 static void ssh2_setup_env(struct ssh_channel *c, struct Packet *pktin,
8850 struct ssh2_setup_env_state {
8852 int num_env, env_left, env_ok;
8855 struct Packet *pktout;
8856 crStateP(ssh2_setup_env_state, ctx);
8861 * Send environment variables.
8863 * Simplest thing here is to send all the requests at once, and
8864 * then wait for a whole bunch of successes or failures.
8870 for (val = conf_get_str_strs(ssh->conf, CONF_environmt, NULL, &key);
8872 val = conf_get_str_strs(ssh->conf, CONF_environmt, key, &key)) {
8873 pktout = ssh2_chanreq_init(ssh->mainchan, "env", ssh2_setup_env, s);
8874 ssh2_pkt_addstring(pktout, key);
8875 ssh2_pkt_addstring(pktout, val);
8876 ssh2_pkt_send(ssh, pktout);
8881 logeventf(ssh, "Sent %d environment variables", s->num_env);
8886 s->env_left = s->num_env;
8888 while (s->env_left > 0) {
8889 /* Wait to be called back with either a response packet,
8890 * or NULL meaning clean up and free our data */
8892 if (!pktin) goto out;
8893 if (pktin->type == SSH2_MSG_CHANNEL_SUCCESS)
8898 if (s->env_ok == s->num_env) {
8899 logevent("All environment variables successfully set");
8900 } else if (s->env_ok == 0) {
8901 logevent("All environment variables refused");
8902 c_write_str(ssh, "Server refused to set environment variables\r\n");
8904 logeventf(ssh, "%d environment variables refused",
8905 s->num_env - s->env_ok);
8906 c_write_str(ssh, "Server refused to set all environment variables\r\n");
8914 * Handle the SSH-2 userauth and connection layers.
8916 static void ssh2_msg_authconn(Ssh ssh, struct Packet *pktin)
8918 do_ssh2_authconn(ssh, NULL, 0, pktin);
8921 static void ssh2_response_authconn(struct ssh_channel *c, struct Packet *pktin,
8925 do_ssh2_authconn(c->ssh, NULL, 0, pktin);
8928 static void do_ssh2_authconn(Ssh ssh, const unsigned char *in, int inlen,
8929 struct Packet *pktin)
8931 struct do_ssh2_authconn_state {
8935 AUTH_TYPE_PUBLICKEY,
8936 AUTH_TYPE_PUBLICKEY_OFFER_LOUD,
8937 AUTH_TYPE_PUBLICKEY_OFFER_QUIET,
8939 AUTH_TYPE_GSSAPI, /* always QUIET */
8940 AUTH_TYPE_KEYBOARD_INTERACTIVE,
8941 AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET
8943 int done_service_req;
8944 int gotit, need_pw, can_pubkey, can_passwd, can_keyb_inter;
8945 int tried_pubkey_config, done_agent;
8950 int kbd_inter_refused;
8951 int we_are_in, userauth_success;
8952 prompts_t *cur_prompt;
8957 void *publickey_blob;
8958 int publickey_bloblen;
8959 int privatekey_available, privatekey_encrypted;
8960 char *publickey_algorithm;
8961 char *publickey_comment;
8962 unsigned char agent_request[5], *agent_response, *agentp;
8963 int agent_responselen;
8964 unsigned char *pkblob_in_agent;
8966 char *pkblob, *alg, *commentp;
8967 int pklen, alglen, commentlen;
8968 int siglen, retlen, len;
8969 char *q, *agentreq, *ret;
8971 struct Packet *pktout;
8974 struct ssh_gss_library *gsslib;
8975 Ssh_gss_ctx gss_ctx;
8976 Ssh_gss_buf gss_buf;
8977 Ssh_gss_buf gss_rcvtok, gss_sndtok;
8978 Ssh_gss_name gss_srv_name;
8979 Ssh_gss_stat gss_stat;
8982 crState(do_ssh2_authconn_state);
8986 /* Register as a handler for all the messages this coroutine handles. */
8987 ssh->packet_dispatch[SSH2_MSG_SERVICE_ACCEPT] = ssh2_msg_authconn;
8988 ssh->packet_dispatch[SSH2_MSG_USERAUTH_REQUEST] = ssh2_msg_authconn;
8989 ssh->packet_dispatch[SSH2_MSG_USERAUTH_FAILURE] = ssh2_msg_authconn;
8990 ssh->packet_dispatch[SSH2_MSG_USERAUTH_SUCCESS] = ssh2_msg_authconn;
8991 ssh->packet_dispatch[SSH2_MSG_USERAUTH_BANNER] = ssh2_msg_authconn;
8992 ssh->packet_dispatch[SSH2_MSG_USERAUTH_PK_OK] = ssh2_msg_authconn;
8993 /* ssh->packet_dispatch[SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ] = ssh2_msg_authconn; duplicate case value */
8994 /* ssh->packet_dispatch[SSH2_MSG_USERAUTH_INFO_REQUEST] = ssh2_msg_authconn; duplicate case value */
8995 ssh->packet_dispatch[SSH2_MSG_USERAUTH_INFO_RESPONSE] = ssh2_msg_authconn;
8996 ssh->packet_dispatch[SSH2_MSG_GLOBAL_REQUEST] = ssh2_msg_authconn;
8997 ssh->packet_dispatch[SSH2_MSG_REQUEST_SUCCESS] = ssh2_msg_authconn;
8998 ssh->packet_dispatch[SSH2_MSG_REQUEST_FAILURE] = ssh2_msg_authconn;
8999 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN] = ssh2_msg_authconn;
9000 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_CONFIRMATION] = ssh2_msg_authconn;
9001 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_FAILURE] = ssh2_msg_authconn;
9002 ssh->packet_dispatch[SSH2_MSG_CHANNEL_WINDOW_ADJUST] = ssh2_msg_authconn;
9003 ssh->packet_dispatch[SSH2_MSG_CHANNEL_DATA] = ssh2_msg_authconn;
9004 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EXTENDED_DATA] = ssh2_msg_authconn;
9005 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EOF] = ssh2_msg_authconn;
9006 ssh->packet_dispatch[SSH2_MSG_CHANNEL_CLOSE] = ssh2_msg_authconn;
9008 s->done_service_req = FALSE;
9009 s->we_are_in = s->userauth_success = FALSE;
9010 s->agent_response = NULL;
9012 s->tried_gssapi = FALSE;
9015 if (!ssh->bare_connection) {
9016 if (!conf_get_int(ssh->conf, CONF_ssh_no_userauth)) {
9018 * Request userauth protocol, and await a response to it.
9020 s->pktout = ssh2_pkt_init(SSH2_MSG_SERVICE_REQUEST);
9021 ssh2_pkt_addstring(s->pktout, "ssh-userauth");
9022 ssh2_pkt_send(ssh, s->pktout);
9023 crWaitUntilV(pktin);
9024 if (pktin->type == SSH2_MSG_SERVICE_ACCEPT)
9025 s->done_service_req = TRUE;
9027 if (!s->done_service_req) {
9029 * Request connection protocol directly, without authentication.
9031 s->pktout = ssh2_pkt_init(SSH2_MSG_SERVICE_REQUEST);
9032 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9033 ssh2_pkt_send(ssh, s->pktout);
9034 crWaitUntilV(pktin);
9035 if (pktin->type == SSH2_MSG_SERVICE_ACCEPT) {
9036 s->we_are_in = TRUE; /* no auth required */
9038 bombout(("Server refused service request"));
9043 s->we_are_in = TRUE;
9046 /* Arrange to be able to deal with any BANNERs that come in.
9047 * (We do this now as packets may come in during the next bit.) */
9048 bufchain_init(&ssh->banner);
9049 ssh->packet_dispatch[SSH2_MSG_USERAUTH_BANNER] =
9050 ssh2_msg_userauth_banner;
9053 * Misc one-time setup for authentication.
9055 s->publickey_blob = NULL;
9056 if (!s->we_are_in) {
9059 * Load the public half of any configured public key file
9062 s->keyfile = conf_get_filename(ssh->conf, CONF_keyfile);
9063 if (!filename_is_null(s->keyfile)) {
9065 logeventf(ssh, "Reading key file \"%.150s\"",
9066 filename_to_str(s->keyfile));
9067 keytype = key_type(s->keyfile);
9068 if (keytype == SSH_KEYTYPE_SSH2 ||
9069 keytype == SSH_KEYTYPE_SSH2_PUBLIC_RFC4716 ||
9070 keytype == SSH_KEYTYPE_SSH2_PUBLIC_OPENSSH) {
9073 ssh2_userkey_loadpub(s->keyfile,
9074 &s->publickey_algorithm,
9075 &s->publickey_bloblen,
9076 &s->publickey_comment, &error);
9077 if (s->publickey_blob) {
9078 s->privatekey_available = (keytype == SSH_KEYTYPE_SSH2);
9079 if (!s->privatekey_available)
9080 logeventf(ssh, "Key file contains public key only");
9081 s->privatekey_encrypted =
9082 ssh2_userkey_encrypted(s->keyfile, NULL);
9085 logeventf(ssh, "Unable to load key (%s)",
9087 msgbuf = dupprintf("Unable to load key file "
9088 "\"%.150s\" (%s)\r\n",
9089 filename_to_str(s->keyfile),
9091 c_write_str(ssh, msgbuf);
9096 logeventf(ssh, "Unable to use this key file (%s)",
9097 key_type_to_str(keytype));
9098 msgbuf = dupprintf("Unable to use key file \"%.150s\""
9100 filename_to_str(s->keyfile),
9101 key_type_to_str(keytype));
9102 c_write_str(ssh, msgbuf);
9104 s->publickey_blob = NULL;
9109 * Find out about any keys Pageant has (but if there's a
9110 * public key configured, filter out all others).
9113 s->agent_response = NULL;
9114 s->pkblob_in_agent = NULL;
9115 if (conf_get_int(ssh->conf, CONF_tryagent) && agent_exists()) {
9119 logevent("Pageant is running. Requesting keys.");
9121 /* Request the keys held by the agent. */
9122 PUT_32BIT(s->agent_request, 1);
9123 s->agent_request[4] = SSH2_AGENTC_REQUEST_IDENTITIES;
9124 if (!agent_query(s->agent_request, 5, &r, &s->agent_responselen,
9125 ssh_agent_callback, ssh)) {
9129 bombout(("Unexpected data from server while"
9130 " waiting for agent response"));
9133 } while (pktin || inlen > 0);
9134 r = ssh->agent_response;
9135 s->agent_responselen = ssh->agent_response_len;
9137 s->agent_response = (unsigned char *) r;
9138 if (s->agent_response && s->agent_responselen >= 5 &&
9139 s->agent_response[4] == SSH2_AGENT_IDENTITIES_ANSWER) {
9142 p = s->agent_response + 5;
9143 s->nkeys = toint(GET_32BIT(p));
9146 * Vet the Pageant response to ensure that the key
9147 * count and blob lengths make sense.
9150 logeventf(ssh, "Pageant response contained a negative"
9151 " key count %d", s->nkeys);
9153 goto done_agent_query;
9155 unsigned char *q = p + 4;
9156 int lenleft = s->agent_responselen - 5 - 4;
9158 for (keyi = 0; keyi < s->nkeys; keyi++) {
9159 int bloblen, commentlen;
9161 logeventf(ssh, "Pageant response was truncated");
9163 goto done_agent_query;
9165 bloblen = toint(GET_32BIT(q));
9166 if (bloblen < 0 || bloblen > lenleft) {
9167 logeventf(ssh, "Pageant response was truncated");
9169 goto done_agent_query;
9171 lenleft -= 4 + bloblen;
9173 commentlen = toint(GET_32BIT(q));
9174 if (commentlen < 0 || commentlen > lenleft) {
9175 logeventf(ssh, "Pageant response was truncated");
9177 goto done_agent_query;
9179 lenleft -= 4 + commentlen;
9180 q += 4 + commentlen;
9185 logeventf(ssh, "Pageant has %d SSH-2 keys", s->nkeys);
9186 if (s->publickey_blob) {
9187 /* See if configured key is in agent. */
9188 for (keyi = 0; keyi < s->nkeys; keyi++) {
9189 s->pklen = toint(GET_32BIT(p));
9190 if (s->pklen == s->publickey_bloblen &&
9191 !memcmp(p+4, s->publickey_blob,
9192 s->publickey_bloblen)) {
9193 logeventf(ssh, "Pageant key #%d matches "
9194 "configured key file", keyi);
9196 s->pkblob_in_agent = p;
9200 p += toint(GET_32BIT(p)) + 4; /* comment */
9202 if (!s->pkblob_in_agent) {
9203 logevent("Configured key file not in Pageant");
9208 logevent("Failed to get reply from Pageant");
9216 * We repeat this whole loop, including the username prompt,
9217 * until we manage a successful authentication. If the user
9218 * types the wrong _password_, they can be sent back to the
9219 * beginning to try another username, if this is configured on.
9220 * (If they specify a username in the config, they are never
9221 * asked, even if they do give a wrong password.)
9223 * I think this best serves the needs of
9225 * - the people who have no configuration, no keys, and just
9226 * want to try repeated (username,password) pairs until they
9227 * type both correctly
9229 * - people who have keys and configuration but occasionally
9230 * need to fall back to passwords
9232 * - people with a key held in Pageant, who might not have
9233 * logged in to a particular machine before; so they want to
9234 * type a username, and then _either_ their key will be
9235 * accepted, _or_ they will type a password. If they mistype
9236 * the username they will want to be able to get back and
9239 s->got_username = FALSE;
9240 while (!s->we_are_in) {
9244 if (s->got_username && !conf_get_int(ssh->conf, CONF_change_username)) {
9246 * We got a username last time round this loop, and
9247 * with change_username turned off we don't try to get
9250 } else if ((ssh->username = get_remote_username(ssh->conf)) == NULL) {
9251 int ret; /* need not be kept over crReturn */
9252 s->cur_prompt = new_prompts(ssh->frontend);
9253 s->cur_prompt->to_server = TRUE;
9254 s->cur_prompt->name = dupstr("SSH login name");
9255 add_prompt(s->cur_prompt, dupstr("login as: "), TRUE);
9256 ret = get_userpass_input(s->cur_prompt, NULL, 0);
9259 crWaitUntilV(!pktin);
9260 ret = get_userpass_input(s->cur_prompt, in, inlen);
9265 * get_userpass_input() failed to get a username.
9268 free_prompts(s->cur_prompt);
9269 ssh_disconnect(ssh, "No username provided", NULL, 0, TRUE);
9272 ssh->username = dupstr(s->cur_prompt->prompts[0]->result);
9273 free_prompts(s->cur_prompt);
9276 if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
9277 stuff = dupprintf("Using username \"%s\".\r\n", ssh->username);
9278 c_write_str(ssh, stuff);
9282 s->got_username = TRUE;
9285 * Send an authentication request using method "none": (a)
9286 * just in case it succeeds, and (b) so that we know what
9287 * authentication methods we can usefully try next.
9289 ssh->pkt_actx = SSH2_PKTCTX_NOAUTH;
9291 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9292 ssh2_pkt_addstring(s->pktout, ssh->username);
9293 ssh2_pkt_addstring(s->pktout, "ssh-connection");/* service requested */
9294 ssh2_pkt_addstring(s->pktout, "none"); /* method */
9295 ssh2_pkt_send(ssh, s->pktout);
9296 s->type = AUTH_TYPE_NONE;
9298 s->we_are_in = FALSE;
9300 s->tried_pubkey_config = FALSE;
9301 s->kbd_inter_refused = FALSE;
9303 /* Reset agent request state. */
9304 s->done_agent = FALSE;
9305 if (s->agent_response) {
9306 if (s->pkblob_in_agent) {
9307 s->agentp = s->pkblob_in_agent;
9309 s->agentp = s->agent_response + 5 + 4;
9315 char *methods = NULL;
9319 * Wait for the result of the last authentication request.
9322 crWaitUntilV(pktin);
9324 * Now is a convenient point to spew any banner material
9325 * that we've accumulated. (This should ensure that when
9326 * we exit the auth loop, we haven't any left to deal
9330 int size = bufchain_size(&ssh->banner);
9332 * Don't show the banner if we're operating in
9333 * non-verbose non-interactive mode. (It's probably
9334 * a script, which means nobody will read the
9335 * banner _anyway_, and moreover the printing of
9336 * the banner will screw up processing on the
9337 * output of (say) plink.)
9339 if (size && (flags & (FLAG_VERBOSE | FLAG_INTERACTIVE))) {
9340 char *banner = snewn(size, char);
9341 bufchain_fetch(&ssh->banner, banner, size);
9342 c_write_untrusted(ssh, banner, size);
9345 bufchain_clear(&ssh->banner);
9347 if (pktin->type == SSH2_MSG_USERAUTH_SUCCESS) {
9348 logevent("Access granted");
9349 s->we_are_in = s->userauth_success = TRUE;
9353 if (pktin->type != SSH2_MSG_USERAUTH_FAILURE && s->type != AUTH_TYPE_GSSAPI) {
9354 bombout(("Strange packet received during authentication: "
9355 "type %d", pktin->type));
9362 * OK, we're now sitting on a USERAUTH_FAILURE message, so
9363 * we can look at the string in it and know what we can
9364 * helpfully try next.
9366 if (pktin->type == SSH2_MSG_USERAUTH_FAILURE) {
9367 ssh_pkt_getstring(pktin, &methods, &methlen);
9368 if (!ssh2_pkt_getbool(pktin)) {
9370 * We have received an unequivocal Access
9371 * Denied. This can translate to a variety of
9372 * messages, or no message at all.
9374 * For forms of authentication which are attempted
9375 * implicitly, by which I mean without printing
9376 * anything in the window indicating that we're
9377 * trying them, we should never print 'Access
9380 * If we do print a message saying that we're
9381 * attempting some kind of authentication, it's OK
9382 * to print a followup message saying it failed -
9383 * but the message may sometimes be more specific
9384 * than simply 'Access denied'.
9386 * Additionally, if we'd just tried password
9387 * authentication, we should break out of this
9388 * whole loop so as to go back to the username
9389 * prompt (iff we're configured to allow
9390 * username change attempts).
9392 if (s->type == AUTH_TYPE_NONE) {
9394 } else if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD ||
9395 s->type == AUTH_TYPE_PUBLICKEY_OFFER_QUIET) {
9396 if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD)
9397 c_write_str(ssh, "Server refused our key\r\n");
9398 logevent("Server refused our key");
9399 } else if (s->type == AUTH_TYPE_PUBLICKEY) {
9400 /* This _shouldn't_ happen except by a
9401 * protocol bug causing client and server to
9402 * disagree on what is a correct signature. */
9403 c_write_str(ssh, "Server refused public-key signature"
9404 " despite accepting key!\r\n");
9405 logevent("Server refused public-key signature"
9406 " despite accepting key!");
9407 } else if (s->type==AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET) {
9408 /* quiet, so no c_write */
9409 logevent("Server refused keyboard-interactive authentication");
9410 } else if (s->type==AUTH_TYPE_GSSAPI) {
9411 /* always quiet, so no c_write */
9412 /* also, the code down in the GSSAPI block has
9413 * already logged this in the Event Log */
9414 } else if (s->type == AUTH_TYPE_KEYBOARD_INTERACTIVE) {
9415 logevent("Keyboard-interactive authentication failed");
9416 c_write_str(ssh, "Access denied\r\n");
9418 assert(s->type == AUTH_TYPE_PASSWORD);
9419 logevent("Password authentication failed");
9420 c_write_str(ssh, "Access denied\r\n");
9422 if (conf_get_int(ssh->conf, CONF_change_username)) {
9423 /* XXX perhaps we should allow
9424 * keyboard-interactive to do this too? */
9425 s->we_are_in = FALSE;
9430 c_write_str(ssh, "Further authentication required\r\n");
9431 logevent("Further authentication required");
9435 in_commasep_string("publickey", methods, methlen);
9437 in_commasep_string("password", methods, methlen);
9438 s->can_keyb_inter = conf_get_int(ssh->conf, CONF_try_ki_auth) &&
9439 in_commasep_string("keyboard-interactive", methods, methlen);
9441 if (conf_get_int(ssh->conf, CONF_try_gssapi_auth) &&
9442 in_commasep_string("gssapi-with-mic", methods, methlen)) {
9443 /* Try loading the GSS libraries and see if we
9446 ssh->gsslibs = ssh_gss_setup(ssh->conf);
9447 s->can_gssapi = (ssh->gsslibs->nlibraries > 0);
9449 /* No point in even bothering to try to load the
9450 * GSS libraries, if the user configuration and
9451 * server aren't both prepared to attempt GSSAPI
9452 * auth in the first place. */
9453 s->can_gssapi = FALSE;
9458 ssh->pkt_actx = SSH2_PKTCTX_NOAUTH;
9460 if (s->can_pubkey && !s->done_agent && s->nkeys) {
9463 * Attempt public-key authentication using a key from Pageant.
9466 ssh->pkt_actx = SSH2_PKTCTX_PUBLICKEY;
9468 logeventf(ssh, "Trying Pageant key #%d", s->keyi);
9470 /* Unpack key from agent response */
9471 s->pklen = toint(GET_32BIT(s->agentp));
9473 s->pkblob = (char *)s->agentp;
9474 s->agentp += s->pklen;
9475 s->alglen = toint(GET_32BIT(s->pkblob));
9476 s->alg = s->pkblob + 4;
9477 s->commentlen = toint(GET_32BIT(s->agentp));
9479 s->commentp = (char *)s->agentp;
9480 s->agentp += s->commentlen;
9481 /* s->agentp now points at next key, if any */
9483 /* See if server will accept it */
9484 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9485 ssh2_pkt_addstring(s->pktout, ssh->username);
9486 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9487 /* service requested */
9488 ssh2_pkt_addstring(s->pktout, "publickey");
9490 ssh2_pkt_addbool(s->pktout, FALSE); /* no signature included */
9491 ssh2_pkt_addstring_start(s->pktout);
9492 ssh2_pkt_addstring_data(s->pktout, s->alg, s->alglen);
9493 ssh2_pkt_addstring_start(s->pktout);
9494 ssh2_pkt_addstring_data(s->pktout, s->pkblob, s->pklen);
9495 ssh2_pkt_send(ssh, s->pktout);
9496 s->type = AUTH_TYPE_PUBLICKEY_OFFER_QUIET;
9498 crWaitUntilV(pktin);
9499 if (pktin->type != SSH2_MSG_USERAUTH_PK_OK) {
9501 /* Offer of key refused. */
9508 if (flags & FLAG_VERBOSE) {
9509 c_write_str(ssh, "Authenticating with "
9511 c_write(ssh, s->commentp, s->commentlen);
9512 c_write_str(ssh, "\" from agent\r\n");
9516 * Server is willing to accept the key.
9517 * Construct a SIGN_REQUEST.
9519 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9520 ssh2_pkt_addstring(s->pktout, ssh->username);
9521 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9522 /* service requested */
9523 ssh2_pkt_addstring(s->pktout, "publickey");
9525 ssh2_pkt_addbool(s->pktout, TRUE); /* signature included */
9526 ssh2_pkt_addstring_start(s->pktout);
9527 ssh2_pkt_addstring_data(s->pktout, s->alg, s->alglen);
9528 ssh2_pkt_addstring_start(s->pktout);
9529 ssh2_pkt_addstring_data(s->pktout, s->pkblob, s->pklen);
9531 /* Ask agent for signature. */
9532 s->siglen = s->pktout->length - 5 + 4 +
9533 ssh->v2_session_id_len;
9534 if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
9536 s->len = 1; /* message type */
9537 s->len += 4 + s->pklen; /* key blob */
9538 s->len += 4 + s->siglen; /* data to sign */
9539 s->len += 4; /* flags */
9540 s->agentreq = snewn(4 + s->len, char);
9541 PUT_32BIT(s->agentreq, s->len);
9542 s->q = s->agentreq + 4;
9543 *s->q++ = SSH2_AGENTC_SIGN_REQUEST;
9544 PUT_32BIT(s->q, s->pklen);
9546 memcpy(s->q, s->pkblob, s->pklen);
9548 PUT_32BIT(s->q, s->siglen);
9550 /* Now the data to be signed... */
9551 if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
9552 PUT_32BIT(s->q, ssh->v2_session_id_len);
9555 memcpy(s->q, ssh->v2_session_id,
9556 ssh->v2_session_id_len);
9557 s->q += ssh->v2_session_id_len;
9558 memcpy(s->q, s->pktout->data + 5,
9559 s->pktout->length - 5);
9560 s->q += s->pktout->length - 5;
9561 /* And finally the (zero) flags word. */
9563 if (!agent_query(s->agentreq, s->len + 4,
9565 ssh_agent_callback, ssh)) {
9569 bombout(("Unexpected data from server"
9570 " while waiting for agent"
9574 } while (pktin || inlen > 0);
9575 vret = ssh->agent_response;
9576 s->retlen = ssh->agent_response_len;
9581 if (s->retlen >= 9 &&
9582 s->ret[4] == SSH2_AGENT_SIGN_RESPONSE &&
9583 GET_32BIT(s->ret + 5) <= (unsigned)(s->retlen-9)) {
9584 logevent("Sending Pageant's response");
9585 ssh2_add_sigblob(ssh, s->pktout,
9586 s->pkblob, s->pklen,
9588 GET_32BIT(s->ret + 5));
9589 ssh2_pkt_send(ssh, s->pktout);
9590 s->type = AUTH_TYPE_PUBLICKEY;
9592 /* FIXME: less drastic response */
9593 bombout(("Pageant failed to answer challenge"));
9599 /* Do we have any keys left to try? */
9600 if (s->pkblob_in_agent) {
9601 s->done_agent = TRUE;
9602 s->tried_pubkey_config = TRUE;
9605 if (s->keyi >= s->nkeys)
9606 s->done_agent = TRUE;
9609 } else if (s->can_pubkey && s->publickey_blob &&
9610 s->privatekey_available && !s->tried_pubkey_config) {
9612 struct ssh2_userkey *key; /* not live over crReturn */
9613 char *passphrase; /* not live over crReturn */
9615 ssh->pkt_actx = SSH2_PKTCTX_PUBLICKEY;
9617 s->tried_pubkey_config = TRUE;
9620 * Try the public key supplied in the configuration.
9622 * First, offer the public blob to see if the server is
9623 * willing to accept it.
9625 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9626 ssh2_pkt_addstring(s->pktout, ssh->username);
9627 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9628 /* service requested */
9629 ssh2_pkt_addstring(s->pktout, "publickey"); /* method */
9630 ssh2_pkt_addbool(s->pktout, FALSE);
9631 /* no signature included */
9632 ssh2_pkt_addstring(s->pktout, s->publickey_algorithm);
9633 ssh2_pkt_addstring_start(s->pktout);
9634 ssh2_pkt_addstring_data(s->pktout,
9635 (char *)s->publickey_blob,
9636 s->publickey_bloblen);
9637 ssh2_pkt_send(ssh, s->pktout);
9638 logevent("Offered public key");
9640 crWaitUntilV(pktin);
9641 if (pktin->type != SSH2_MSG_USERAUTH_PK_OK) {
9642 /* Key refused. Give up. */
9643 s->gotit = TRUE; /* reconsider message next loop */
9644 s->type = AUTH_TYPE_PUBLICKEY_OFFER_LOUD;
9645 continue; /* process this new message */
9647 logevent("Offer of public key accepted");
9650 * Actually attempt a serious authentication using
9653 if (flags & FLAG_VERBOSE) {
9654 c_write_str(ssh, "Authenticating with public key \"");
9655 c_write_str(ssh, s->publickey_comment);
9656 c_write_str(ssh, "\"\r\n");
9660 const char *error; /* not live over crReturn */
9661 if (s->privatekey_encrypted) {
9663 * Get a passphrase from the user.
9665 int ret; /* need not be kept over crReturn */
9666 s->cur_prompt = new_prompts(ssh->frontend);
9667 s->cur_prompt->to_server = FALSE;
9668 s->cur_prompt->name = dupstr("SSH key passphrase");
9669 add_prompt(s->cur_prompt,
9670 dupprintf("Passphrase for key \"%.100s\": ",
9671 s->publickey_comment),
9673 ret = get_userpass_input(s->cur_prompt, NULL, 0);
9676 crWaitUntilV(!pktin);
9677 ret = get_userpass_input(s->cur_prompt,
9682 /* Failed to get a passphrase. Terminate. */
9683 free_prompts(s->cur_prompt);
9684 ssh_disconnect(ssh, NULL,
9685 "Unable to authenticate",
9686 SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER,
9691 dupstr(s->cur_prompt->prompts[0]->result);
9692 free_prompts(s->cur_prompt);
9694 passphrase = NULL; /* no passphrase needed */
9698 * Try decrypting the key.
9700 s->keyfile = conf_get_filename(ssh->conf, CONF_keyfile);
9701 key = ssh2_load_userkey(s->keyfile, passphrase, &error);
9703 /* burn the evidence */
9704 smemclr(passphrase, strlen(passphrase));
9707 if (key == SSH2_WRONG_PASSPHRASE || key == NULL) {
9709 (key == SSH2_WRONG_PASSPHRASE)) {
9710 c_write_str(ssh, "Wrong passphrase\r\n");
9712 /* and loop again */
9714 c_write_str(ssh, "Unable to load private key (");
9715 c_write_str(ssh, error);
9716 c_write_str(ssh, ")\r\n");
9718 break; /* try something else */
9724 unsigned char *pkblob, *sigblob, *sigdata;
9725 int pkblob_len, sigblob_len, sigdata_len;
9729 * We have loaded the private key and the server
9730 * has announced that it's willing to accept it.
9731 * Hallelujah. Generate a signature and send it.
9733 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9734 ssh2_pkt_addstring(s->pktout, ssh->username);
9735 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9736 /* service requested */
9737 ssh2_pkt_addstring(s->pktout, "publickey");
9739 ssh2_pkt_addbool(s->pktout, TRUE);
9740 /* signature follows */
9741 ssh2_pkt_addstring(s->pktout, key->alg->name);
9742 pkblob = key->alg->public_blob(key->data,
9744 ssh2_pkt_addstring_start(s->pktout);
9745 ssh2_pkt_addstring_data(s->pktout, (char *)pkblob,
9749 * The data to be signed is:
9753 * followed by everything so far placed in the
9756 sigdata_len = s->pktout->length - 5 + 4 +
9757 ssh->v2_session_id_len;
9758 if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
9760 sigdata = snewn(sigdata_len, unsigned char);
9762 if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
9763 PUT_32BIT(sigdata+p, ssh->v2_session_id_len);
9766 memcpy(sigdata+p, ssh->v2_session_id,
9767 ssh->v2_session_id_len);
9768 p += ssh->v2_session_id_len;
9769 memcpy(sigdata+p, s->pktout->data + 5,
9770 s->pktout->length - 5);
9771 p += s->pktout->length - 5;
9772 assert(p == sigdata_len);
9773 sigblob = key->alg->sign(key->data, (char *)sigdata,
9774 sigdata_len, &sigblob_len);
9775 ssh2_add_sigblob(ssh, s->pktout, pkblob, pkblob_len,
9776 sigblob, sigblob_len);
9781 ssh2_pkt_send(ssh, s->pktout);
9782 logevent("Sent public key signature");
9783 s->type = AUTH_TYPE_PUBLICKEY;
9784 key->alg->freekey(key->data);
9785 sfree(key->comment);
9790 } else if (s->can_gssapi && !s->tried_gssapi) {
9792 /* GSSAPI Authentication */
9797 s->type = AUTH_TYPE_GSSAPI;
9798 s->tried_gssapi = TRUE;
9800 ssh->pkt_actx = SSH2_PKTCTX_GSSAPI;
9803 * Pick the highest GSS library on the preference
9809 for (i = 0; i < ngsslibs; i++) {
9810 int want_id = conf_get_int_int(ssh->conf,
9811 CONF_ssh_gsslist, i);
9812 for (j = 0; j < ssh->gsslibs->nlibraries; j++)
9813 if (ssh->gsslibs->libraries[j].id == want_id) {
9814 s->gsslib = &ssh->gsslibs->libraries[j];
9815 goto got_gsslib; /* double break */
9820 * We always expect to have found something in
9821 * the above loop: we only came here if there
9822 * was at least one viable GSS library, and the
9823 * preference list should always mention
9824 * everything and only change the order.
9829 if (s->gsslib->gsslogmsg)
9830 logevent(s->gsslib->gsslogmsg);
9832 /* Sending USERAUTH_REQUEST with "gssapi-with-mic" method */
9833 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9834 ssh2_pkt_addstring(s->pktout, ssh->username);
9835 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9836 ssh2_pkt_addstring(s->pktout, "gssapi-with-mic");
9837 logevent("Attempting GSSAPI authentication");
9839 /* add mechanism info */
9840 s->gsslib->indicate_mech(s->gsslib, &s->gss_buf);
9842 /* number of GSSAPI mechanisms */
9843 ssh2_pkt_adduint32(s->pktout,1);
9845 /* length of OID + 2 */
9846 ssh2_pkt_adduint32(s->pktout, s->gss_buf.length + 2);
9847 ssh2_pkt_addbyte(s->pktout, SSH2_GSS_OIDTYPE);
9850 ssh2_pkt_addbyte(s->pktout, (unsigned char) s->gss_buf.length);
9852 ssh_pkt_adddata(s->pktout, s->gss_buf.value,
9854 ssh2_pkt_send(ssh, s->pktout);
9855 crWaitUntilV(pktin);
9856 if (pktin->type != SSH2_MSG_USERAUTH_GSSAPI_RESPONSE) {
9857 logevent("GSSAPI authentication request refused");
9861 /* check returned packet ... */
9863 ssh_pkt_getstring(pktin, &data, &len);
9864 s->gss_rcvtok.value = data;
9865 s->gss_rcvtok.length = len;
9866 if (s->gss_rcvtok.length != s->gss_buf.length + 2 ||
9867 ((char *)s->gss_rcvtok.value)[0] != SSH2_GSS_OIDTYPE ||
9868 ((char *)s->gss_rcvtok.value)[1] != s->gss_buf.length ||
9869 memcmp((char *)s->gss_rcvtok.value + 2,
9870 s->gss_buf.value,s->gss_buf.length) ) {
9871 logevent("GSSAPI authentication - wrong response from server");
9875 /* now start running */
9876 s->gss_stat = s->gsslib->import_name(s->gsslib,
9879 if (s->gss_stat != SSH_GSS_OK) {
9880 if (s->gss_stat == SSH_GSS_BAD_HOST_NAME)
9881 logevent("GSSAPI import name failed - Bad service name");
9883 logevent("GSSAPI import name failed");
9887 /* fetch TGT into GSS engine */
9888 s->gss_stat = s->gsslib->acquire_cred(s->gsslib, &s->gss_ctx);
9890 if (s->gss_stat != SSH_GSS_OK) {
9891 logevent("GSSAPI authentication failed to get credentials");
9892 s->gsslib->release_name(s->gsslib, &s->gss_srv_name);
9896 /* initial tokens are empty */
9897 SSH_GSS_CLEAR_BUF(&s->gss_rcvtok);
9898 SSH_GSS_CLEAR_BUF(&s->gss_sndtok);
9900 /* now enter the loop */
9902 s->gss_stat = s->gsslib->init_sec_context
9906 conf_get_int(ssh->conf, CONF_gssapifwd),
9910 if (s->gss_stat!=SSH_GSS_S_COMPLETE &&
9911 s->gss_stat!=SSH_GSS_S_CONTINUE_NEEDED) {
9912 logevent("GSSAPI authentication initialisation failed");
9914 if (s->gsslib->display_status(s->gsslib, s->gss_ctx,
9915 &s->gss_buf) == SSH_GSS_OK) {
9916 logevent(s->gss_buf.value);
9917 sfree(s->gss_buf.value);
9922 logevent("GSSAPI authentication initialised");
9924 /* Client and server now exchange tokens until GSSAPI
9925 * no longer says CONTINUE_NEEDED */
9927 if (s->gss_sndtok.length != 0) {
9928 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
9929 ssh_pkt_addstring_start(s->pktout);
9930 ssh_pkt_addstring_data(s->pktout,s->gss_sndtok.value,s->gss_sndtok.length);
9931 ssh2_pkt_send(ssh, s->pktout);
9932 s->gsslib->free_tok(s->gsslib, &s->gss_sndtok);
9935 if (s->gss_stat == SSH_GSS_S_CONTINUE_NEEDED) {
9936 crWaitUntilV(pktin);
9937 if (pktin->type != SSH2_MSG_USERAUTH_GSSAPI_TOKEN) {
9938 logevent("GSSAPI authentication - bad server response");
9939 s->gss_stat = SSH_GSS_FAILURE;
9942 ssh_pkt_getstring(pktin, &data, &len);
9943 s->gss_rcvtok.value = data;
9944 s->gss_rcvtok.length = len;
9946 } while (s-> gss_stat == SSH_GSS_S_CONTINUE_NEEDED);
9948 if (s->gss_stat != SSH_GSS_OK) {
9949 s->gsslib->release_name(s->gsslib, &s->gss_srv_name);
9950 s->gsslib->release_cred(s->gsslib, &s->gss_ctx);
9953 logevent("GSSAPI authentication loop finished OK");
9955 /* Now send the MIC */
9957 s->pktout = ssh2_pkt_init(0);
9958 micoffset = s->pktout->length;
9959 ssh_pkt_addstring_start(s->pktout);
9960 ssh_pkt_addstring_data(s->pktout, (char *)ssh->v2_session_id, ssh->v2_session_id_len);
9961 ssh_pkt_addbyte(s->pktout, SSH2_MSG_USERAUTH_REQUEST);
9962 ssh_pkt_addstring(s->pktout, ssh->username);
9963 ssh_pkt_addstring(s->pktout, "ssh-connection");
9964 ssh_pkt_addstring(s->pktout, "gssapi-with-mic");
9966 s->gss_buf.value = (char *)s->pktout->data + micoffset;
9967 s->gss_buf.length = s->pktout->length - micoffset;
9969 s->gsslib->get_mic(s->gsslib, s->gss_ctx, &s->gss_buf, &mic);
9970 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_GSSAPI_MIC);
9971 ssh_pkt_addstring_start(s->pktout);
9972 ssh_pkt_addstring_data(s->pktout, mic.value, mic.length);
9973 ssh2_pkt_send(ssh, s->pktout);
9974 s->gsslib->free_mic(s->gsslib, &mic);
9978 s->gsslib->release_name(s->gsslib, &s->gss_srv_name);
9979 s->gsslib->release_cred(s->gsslib, &s->gss_ctx);
9982 } else if (s->can_keyb_inter && !s->kbd_inter_refused) {
9985 * Keyboard-interactive authentication.
9988 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
9990 ssh->pkt_actx = SSH2_PKTCTX_KBDINTER;
9992 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9993 ssh2_pkt_addstring(s->pktout, ssh->username);
9994 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9995 /* service requested */
9996 ssh2_pkt_addstring(s->pktout, "keyboard-interactive");
9998 ssh2_pkt_addstring(s->pktout, ""); /* lang */
9999 ssh2_pkt_addstring(s->pktout, ""); /* submethods */
10000 ssh2_pkt_send(ssh, s->pktout);
10002 logevent("Attempting keyboard-interactive authentication");
10004 crWaitUntilV(pktin);
10005 if (pktin->type != SSH2_MSG_USERAUTH_INFO_REQUEST) {
10006 /* Server is not willing to do keyboard-interactive
10007 * at all (or, bizarrely but legally, accepts the
10008 * user without actually issuing any prompts).
10009 * Give up on it entirely. */
10011 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET;
10012 s->kbd_inter_refused = TRUE; /* don't try it again */
10017 * Loop while the server continues to send INFO_REQUESTs.
10019 while (pktin->type == SSH2_MSG_USERAUTH_INFO_REQUEST) {
10021 char *name, *inst, *lang;
10022 int name_len, inst_len, lang_len;
10026 * We've got a fresh USERAUTH_INFO_REQUEST.
10027 * Get the preamble and start building a prompt.
10029 ssh_pkt_getstring(pktin, &name, &name_len);
10030 ssh_pkt_getstring(pktin, &inst, &inst_len);
10031 ssh_pkt_getstring(pktin, &lang, &lang_len);
10032 s->cur_prompt = new_prompts(ssh->frontend);
10033 s->cur_prompt->to_server = TRUE;
10036 * Get any prompt(s) from the packet.
10038 s->num_prompts = ssh_pkt_getuint32(pktin);
10039 for (i = 0; i < s->num_prompts; i++) {
10043 static char noprompt[] =
10044 "<server failed to send prompt>: ";
10046 ssh_pkt_getstring(pktin, &prompt, &prompt_len);
10047 echo = ssh2_pkt_getbool(pktin);
10050 prompt_len = lenof(noprompt)-1;
10052 add_prompt(s->cur_prompt,
10053 dupprintf("%.*s", prompt_len, prompt),
10058 /* FIXME: better prefix to distinguish from
10059 * local prompts? */
10060 s->cur_prompt->name =
10061 dupprintf("SSH server: %.*s", name_len, name);
10062 s->cur_prompt->name_reqd = TRUE;
10064 s->cur_prompt->name =
10065 dupstr("SSH server authentication");
10066 s->cur_prompt->name_reqd = FALSE;
10068 /* We add a prefix to try to make it clear that a prompt
10069 * has come from the server.
10070 * FIXME: ugly to print "Using..." in prompt _every_
10071 * time round. Can this be done more subtly? */
10072 /* Special case: for reasons best known to themselves,
10073 * some servers send k-i requests with no prompts and
10074 * nothing to display. Keep quiet in this case. */
10075 if (s->num_prompts || name_len || inst_len) {
10076 s->cur_prompt->instruction =
10077 dupprintf("Using keyboard-interactive authentication.%s%.*s",
10078 inst_len ? "\n" : "", inst_len, inst);
10079 s->cur_prompt->instr_reqd = TRUE;
10081 s->cur_prompt->instr_reqd = FALSE;
10085 * Display any instructions, and get the user's
10089 int ret; /* not live over crReturn */
10090 ret = get_userpass_input(s->cur_prompt, NULL, 0);
10093 crWaitUntilV(!pktin);
10094 ret = get_userpass_input(s->cur_prompt, in, inlen);
10099 * Failed to get responses. Terminate.
10101 free_prompts(s->cur_prompt);
10102 ssh_disconnect(ssh, NULL, "Unable to authenticate",
10103 SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER,
10110 * Send the response(s) to the server.
10112 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_INFO_RESPONSE);
10113 ssh2_pkt_adduint32(s->pktout, s->num_prompts);
10114 for (i=0; i < s->num_prompts; i++) {
10115 ssh2_pkt_addstring(s->pktout,
10116 s->cur_prompt->prompts[i]->result);
10118 ssh2_pkt_send_with_padding(ssh, s->pktout, 256);
10121 * Free the prompts structure from this iteration.
10122 * If there's another, a new one will be allocated
10123 * when we return to the top of this while loop.
10125 free_prompts(s->cur_prompt);
10128 * Get the next packet in case it's another
10131 crWaitUntilV(pktin);
10136 * We should have SUCCESS or FAILURE now.
10140 } else if (s->can_passwd) {
10143 * Plain old password authentication.
10145 int ret; /* not live over crReturn */
10146 int changereq_first_time; /* not live over crReturn */
10148 ssh->pkt_actx = SSH2_PKTCTX_PASSWORD;
10150 s->cur_prompt = new_prompts(ssh->frontend);
10151 s->cur_prompt->to_server = TRUE;
10152 s->cur_prompt->name = dupstr("SSH password");
10153 add_prompt(s->cur_prompt, dupprintf("%s@%s's password: ",
10158 ret = get_userpass_input(s->cur_prompt, NULL, 0);
10161 crWaitUntilV(!pktin);
10162 ret = get_userpass_input(s->cur_prompt, in, inlen);
10167 * Failed to get responses. Terminate.
10169 free_prompts(s->cur_prompt);
10170 ssh_disconnect(ssh, NULL, "Unable to authenticate",
10171 SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER,
10176 * Squirrel away the password. (We may need it later if
10177 * asked to change it.)
10179 s->password = dupstr(s->cur_prompt->prompts[0]->result);
10180 free_prompts(s->cur_prompt);
10183 * Send the password packet.
10185 * We pad out the password packet to 256 bytes to make
10186 * it harder for an attacker to find the length of the
10189 * Anyone using a password longer than 256 bytes
10190 * probably doesn't have much to worry about from
10191 * people who find out how long their password is!
10193 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
10194 ssh2_pkt_addstring(s->pktout, ssh->username);
10195 ssh2_pkt_addstring(s->pktout, "ssh-connection");
10196 /* service requested */
10197 ssh2_pkt_addstring(s->pktout, "password");
10198 ssh2_pkt_addbool(s->pktout, FALSE);
10199 ssh2_pkt_addstring(s->pktout, s->password);
10200 ssh2_pkt_send_with_padding(ssh, s->pktout, 256);
10201 logevent("Sent password");
10202 s->type = AUTH_TYPE_PASSWORD;
10205 * Wait for next packet, in case it's a password change
10208 crWaitUntilV(pktin);
10209 changereq_first_time = TRUE;
10211 while (pktin->type == SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ) {
10214 * We're being asked for a new password
10215 * (perhaps not for the first time).
10216 * Loop until the server accepts it.
10219 int got_new = FALSE; /* not live over crReturn */
10220 char *prompt; /* not live over crReturn */
10221 int prompt_len; /* not live over crReturn */
10225 if (changereq_first_time)
10226 msg = "Server requested password change";
10228 msg = "Server rejected new password";
10230 c_write_str(ssh, msg);
10231 c_write_str(ssh, "\r\n");
10234 ssh_pkt_getstring(pktin, &prompt, &prompt_len);
10236 s->cur_prompt = new_prompts(ssh->frontend);
10237 s->cur_prompt->to_server = TRUE;
10238 s->cur_prompt->name = dupstr("New SSH password");
10239 s->cur_prompt->instruction =
10240 dupprintf("%.*s", prompt_len, prompt);
10241 s->cur_prompt->instr_reqd = TRUE;
10243 * There's no explicit requirement in the protocol
10244 * for the "old" passwords in the original and
10245 * password-change messages to be the same, and
10246 * apparently some Cisco kit supports password change
10247 * by the user entering a blank password originally
10248 * and the real password subsequently, so,
10249 * reluctantly, we prompt for the old password again.
10251 * (On the other hand, some servers don't even bother
10252 * to check this field.)
10254 add_prompt(s->cur_prompt,
10255 dupstr("Current password (blank for previously entered password): "),
10257 add_prompt(s->cur_prompt, dupstr("Enter new password: "),
10259 add_prompt(s->cur_prompt, dupstr("Confirm new password: "),
10263 * Loop until the user manages to enter the same
10268 ret = get_userpass_input(s->cur_prompt, NULL, 0);
10271 crWaitUntilV(!pktin);
10272 ret = get_userpass_input(s->cur_prompt, in, inlen);
10277 * Failed to get responses. Terminate.
10279 /* burn the evidence */
10280 free_prompts(s->cur_prompt);
10281 smemclr(s->password, strlen(s->password));
10282 sfree(s->password);
10283 ssh_disconnect(ssh, NULL, "Unable to authenticate",
10284 SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER,
10290 * If the user specified a new original password
10291 * (IYSWIM), overwrite any previously specified
10293 * (A side effect is that the user doesn't have to
10294 * re-enter it if they louse up the new password.)
10296 if (s->cur_prompt->prompts[0]->result[0]) {
10297 smemclr(s->password, strlen(s->password));
10298 /* burn the evidence */
10299 sfree(s->password);
10301 dupstr(s->cur_prompt->prompts[0]->result);
10305 * Check the two new passwords match.
10307 got_new = (strcmp(s->cur_prompt->prompts[1]->result,
10308 s->cur_prompt->prompts[2]->result)
10311 /* They don't. Silly user. */
10312 c_write_str(ssh, "Passwords do not match\r\n");
10317 * Send the new password (along with the old one).
10318 * (see above for padding rationale)
10320 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
10321 ssh2_pkt_addstring(s->pktout, ssh->username);
10322 ssh2_pkt_addstring(s->pktout, "ssh-connection");
10323 /* service requested */
10324 ssh2_pkt_addstring(s->pktout, "password");
10325 ssh2_pkt_addbool(s->pktout, TRUE);
10326 ssh2_pkt_addstring(s->pktout, s->password);
10327 ssh2_pkt_addstring(s->pktout,
10328 s->cur_prompt->prompts[1]->result);
10329 free_prompts(s->cur_prompt);
10330 ssh2_pkt_send_with_padding(ssh, s->pktout, 256);
10331 logevent("Sent new password");
10334 * Now see what the server has to say about it.
10335 * (If it's CHANGEREQ again, it's not happy with the
10338 crWaitUntilV(pktin);
10339 changereq_first_time = FALSE;
10344 * We need to reexamine the current pktin at the top
10345 * of the loop. Either:
10346 * - we weren't asked to change password at all, in
10347 * which case it's a SUCCESS or FAILURE with the
10349 * - we sent a new password, and the server was
10350 * either OK with it (SUCCESS or FAILURE w/partial
10351 * success) or unhappy with the _old_ password
10352 * (FAILURE w/o partial success)
10353 * In any of these cases, we go back to the top of
10354 * the loop and start again.
10359 * We don't need the old password any more, in any
10360 * case. Burn the evidence.
10362 smemclr(s->password, strlen(s->password));
10363 sfree(s->password);
10366 char *str = dupprintf("No supported authentication methods available"
10367 " (server sent: %.*s)",
10370 ssh_disconnect(ssh, str,
10371 "No supported authentication methods available",
10372 SSH2_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE,
10382 ssh->packet_dispatch[SSH2_MSG_USERAUTH_BANNER] = NULL;
10384 /* Clear up various bits and pieces from authentication. */
10385 if (s->publickey_blob) {
10386 sfree(s->publickey_algorithm);
10387 sfree(s->publickey_blob);
10388 sfree(s->publickey_comment);
10390 if (s->agent_response)
10391 sfree(s->agent_response);
10393 if (s->userauth_success && !ssh->bare_connection) {
10395 * We've just received USERAUTH_SUCCESS, and we haven't sent any
10396 * packets since. Signal the transport layer to consider enacting
10397 * delayed compression.
10399 * (Relying on we_are_in is not sufficient, as
10400 * draft-miller-secsh-compression-delayed is quite clear that it
10401 * triggers on USERAUTH_SUCCESS specifically, and we_are_in can
10402 * become set for other reasons.)
10404 do_ssh2_transport(ssh, "enabling delayed compression", -2, NULL);
10407 ssh->channels = newtree234(ssh_channelcmp);
10410 * Set up handlers for some connection protocol messages, so we
10411 * don't have to handle them repeatedly in this coroutine.
10413 ssh->packet_dispatch[SSH2_MSG_CHANNEL_WINDOW_ADJUST] =
10414 ssh2_msg_channel_window_adjust;
10415 ssh->packet_dispatch[SSH2_MSG_GLOBAL_REQUEST] =
10416 ssh2_msg_global_request;
10419 * Create the main session channel.
10421 if (conf_get_int(ssh->conf, CONF_ssh_no_shell)) {
10422 ssh->mainchan = NULL;
10424 ssh->mainchan = snew(struct ssh_channel);
10425 ssh->mainchan->ssh = ssh;
10426 ssh2_channel_init(ssh->mainchan);
10428 if (*conf_get_str(ssh->conf, CONF_ssh_nc_host)) {
10430 * Just start a direct-tcpip channel and use it as the main
10433 ssh_send_port_open(ssh->mainchan,
10434 conf_get_str(ssh->conf, CONF_ssh_nc_host),
10435 conf_get_int(ssh->conf, CONF_ssh_nc_port),
10437 ssh->ncmode = TRUE;
10439 s->pktout = ssh2_chanopen_init(ssh->mainchan, "session");
10440 logevent("Opening session as main channel");
10441 ssh2_pkt_send(ssh, s->pktout);
10442 ssh->ncmode = FALSE;
10444 crWaitUntilV(pktin);
10445 if (pktin->type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
10446 bombout(("Server refused to open channel"));
10448 /* FIXME: error data comes back in FAILURE packet */
10450 if (ssh_pkt_getuint32(pktin) != ssh->mainchan->localid) {
10451 bombout(("Server's channel confirmation cited wrong channel"));
10454 ssh->mainchan->remoteid = ssh_pkt_getuint32(pktin);
10455 ssh->mainchan->halfopen = FALSE;
10456 ssh->mainchan->type = CHAN_MAINSESSION;
10457 ssh->mainchan->v.v2.remwindow = ssh_pkt_getuint32(pktin);
10458 ssh->mainchan->v.v2.remmaxpkt = ssh_pkt_getuint32(pktin);
10459 add234(ssh->channels, ssh->mainchan);
10460 update_specials_menu(ssh->frontend);
10461 logevent("Opened main channel");
10465 * Now we have a channel, make dispatch table entries for
10466 * general channel-based messages.
10468 ssh->packet_dispatch[SSH2_MSG_CHANNEL_DATA] =
10469 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EXTENDED_DATA] =
10470 ssh2_msg_channel_data;
10471 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EOF] = ssh2_msg_channel_eof;
10472 ssh->packet_dispatch[SSH2_MSG_CHANNEL_CLOSE] = ssh2_msg_channel_close;
10473 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_CONFIRMATION] =
10474 ssh2_msg_channel_open_confirmation;
10475 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_FAILURE] =
10476 ssh2_msg_channel_open_failure;
10477 ssh->packet_dispatch[SSH2_MSG_CHANNEL_REQUEST] =
10478 ssh2_msg_channel_request;
10479 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN] =
10480 ssh2_msg_channel_open;
10481 ssh->packet_dispatch[SSH2_MSG_CHANNEL_SUCCESS] = ssh2_msg_channel_response;
10482 ssh->packet_dispatch[SSH2_MSG_CHANNEL_FAILURE] = ssh2_msg_channel_response;
10485 * Now the connection protocol is properly up and running, with
10486 * all those dispatch table entries, so it's safe to let
10487 * downstreams start trying to open extra channels through us.
10489 if (ssh->connshare)
10490 share_activate(ssh->connshare, ssh->v_s);
10492 if (ssh->mainchan && ssh_is_simple(ssh)) {
10494 * This message indicates to the server that we promise
10495 * not to try to run any other channel in parallel with
10496 * this one, so it's safe for it to advertise a very large
10497 * window and leave the flow control to TCP.
10499 s->pktout = ssh2_chanreq_init(ssh->mainchan,
10500 "simple@putty.projects.tartarus.org",
10502 ssh2_pkt_send(ssh, s->pktout);
10506 * Enable port forwardings.
10508 ssh_setup_portfwd(ssh, ssh->conf);
10510 if (ssh->mainchan && !ssh->ncmode) {
10512 * Send the CHANNEL_REQUESTS for the main session channel.
10513 * Each one is handled by its own little asynchronous
10517 /* Potentially enable X11 forwarding. */
10518 if (conf_get_int(ssh->conf, CONF_x11_forward)) {
10520 x11_setup_display(conf_get_str(ssh->conf, CONF_x11_display),
10522 if (!ssh->x11disp) {
10523 /* FIXME: return an error message from x11_setup_display */
10524 logevent("X11 forwarding not enabled: unable to"
10525 " initialise X display");
10527 ssh->x11auth = x11_invent_fake_auth
10528 (ssh->x11authtree, conf_get_int(ssh->conf, CONF_x11_auth));
10529 ssh->x11auth->disp = ssh->x11disp;
10531 ssh2_setup_x11(ssh->mainchan, NULL, NULL);
10535 /* Potentially enable agent forwarding. */
10536 if (ssh_agent_forwarding_permitted(ssh))
10537 ssh2_setup_agent(ssh->mainchan, NULL, NULL);
10539 /* Now allocate a pty for the session. */
10540 if (!conf_get_int(ssh->conf, CONF_nopty))
10541 ssh2_setup_pty(ssh->mainchan, NULL, NULL);
10543 /* Send environment variables. */
10544 ssh2_setup_env(ssh->mainchan, NULL, NULL);
10547 * Start a shell or a remote command. We may have to attempt
10548 * this twice if the config data has provided a second choice
10555 if (ssh->fallback_cmd) {
10556 subsys = conf_get_int(ssh->conf, CONF_ssh_subsys2);
10557 cmd = conf_get_str(ssh->conf, CONF_remote_cmd2);
10559 subsys = conf_get_int(ssh->conf, CONF_ssh_subsys);
10560 cmd = conf_get_str(ssh->conf, CONF_remote_cmd);
10564 s->pktout = ssh2_chanreq_init(ssh->mainchan, "subsystem",
10565 ssh2_response_authconn, NULL);
10566 ssh2_pkt_addstring(s->pktout, cmd);
10568 s->pktout = ssh2_chanreq_init(ssh->mainchan, "exec",
10569 ssh2_response_authconn, NULL);
10570 ssh2_pkt_addstring(s->pktout, cmd);
10572 s->pktout = ssh2_chanreq_init(ssh->mainchan, "shell",
10573 ssh2_response_authconn, NULL);
10575 ssh2_pkt_send(ssh, s->pktout);
10577 crWaitUntilV(pktin);
10579 if (pktin->type != SSH2_MSG_CHANNEL_SUCCESS) {
10580 if (pktin->type != SSH2_MSG_CHANNEL_FAILURE) {
10581 bombout(("Unexpected response to shell/command request:"
10582 " packet type %d", pktin->type));
10586 * We failed to start the command. If this is the
10587 * fallback command, we really are finished; if it's
10588 * not, and if the fallback command exists, try falling
10589 * back to it before complaining.
10591 if (!ssh->fallback_cmd &&
10592 *conf_get_str(ssh->conf, CONF_remote_cmd2)) {
10593 logevent("Primary command failed; attempting fallback");
10594 ssh->fallback_cmd = TRUE;
10597 bombout(("Server refused to start a shell/command"));
10600 logevent("Started a shell/command");
10605 ssh->editing = ssh->echoing = TRUE;
10608 ssh->state = SSH_STATE_SESSION;
10609 if (ssh->size_needed)
10610 ssh_size(ssh, ssh->term_width, ssh->term_height);
10611 if (ssh->eof_needed)
10612 ssh_special(ssh, TS_EOF);
10618 ldisc_echoedit_update(ssh->ldisc); /* cause ldisc to notice changes */
10623 s->try_send = FALSE;
10627 * _All_ the connection-layer packets we expect to
10628 * receive are now handled by the dispatch table.
10629 * Anything that reaches here must be bogus.
10632 bombout(("Strange packet received: type %d", pktin->type));
10634 } else if (ssh->mainchan) {
10636 * We have spare data. Add it to the channel buffer.
10638 ssh2_add_channel_data(ssh->mainchan, (char *)in, inlen);
10639 s->try_send = TRUE;
10643 struct ssh_channel *c;
10645 * Try to send data on all channels if we can.
10647 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++)
10648 if (c->type != CHAN_SHARING)
10649 ssh2_try_send_and_unthrottle(ssh, c);
10657 * Handlers for SSH-2 messages that might arrive at any moment.
10659 static void ssh2_msg_disconnect(Ssh ssh, struct Packet *pktin)
10661 /* log reason code in disconnect message */
10663 int reason, msglen;
10665 reason = ssh_pkt_getuint32(pktin);
10666 ssh_pkt_getstring(pktin, &msg, &msglen);
10668 if (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) {
10669 buf = dupprintf("Received disconnect message (%s)",
10670 ssh2_disconnect_reasons[reason]);
10672 buf = dupprintf("Received disconnect message (unknown"
10673 " type %d)", reason);
10677 buf = dupprintf("Disconnection message text: %.*s",
10680 bombout(("Server sent disconnect message\ntype %d (%s):\n\"%.*s\"",
10682 (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) ?
10683 ssh2_disconnect_reasons[reason] : "unknown",
10688 static void ssh2_msg_debug(Ssh ssh, struct Packet *pktin)
10690 /* log the debug message */
10694 /* XXX maybe we should actually take notice of the return value */
10695 ssh2_pkt_getbool(pktin);
10696 ssh_pkt_getstring(pktin, &msg, &msglen);
10698 logeventf(ssh, "Remote debug message: %.*s", msglen, msg);
10701 static void ssh2_msg_transport(Ssh ssh, struct Packet *pktin)
10703 do_ssh2_transport(ssh, NULL, 0, pktin);
10707 * Called if we receive a packet that isn't allowed by the protocol.
10708 * This only applies to packets whose meaning PuTTY understands.
10709 * Entirely unknown packets are handled below.
10711 static void ssh2_msg_unexpected(Ssh ssh, struct Packet *pktin)
10713 char *buf = dupprintf("Server protocol violation: unexpected %s packet",
10714 ssh2_pkt_type(ssh->pkt_kctx, ssh->pkt_actx,
10716 ssh_disconnect(ssh, NULL, buf, SSH2_DISCONNECT_PROTOCOL_ERROR, FALSE);
10720 static void ssh2_msg_something_unimplemented(Ssh ssh, struct Packet *pktin)
10722 struct Packet *pktout;
10723 pktout = ssh2_pkt_init(SSH2_MSG_UNIMPLEMENTED);
10724 ssh2_pkt_adduint32(pktout, pktin->sequence);
10726 * UNIMPLEMENTED messages MUST appear in the same order as the
10727 * messages they respond to. Hence, never queue them.
10729 ssh2_pkt_send_noqueue(ssh, pktout);
10733 * Handle the top-level SSH-2 protocol.
10735 static void ssh2_protocol_setup(Ssh ssh)
10740 * Most messages cause SSH2_MSG_UNIMPLEMENTED.
10742 for (i = 0; i < 256; i++)
10743 ssh->packet_dispatch[i] = ssh2_msg_something_unimplemented;
10746 * Initially, we only accept transport messages (and a few generic
10747 * ones). do_ssh2_authconn will add more when it starts.
10748 * Messages that are understood but not currently acceptable go to
10749 * ssh2_msg_unexpected.
10751 ssh->packet_dispatch[SSH2_MSG_UNIMPLEMENTED] = ssh2_msg_unexpected;
10752 ssh->packet_dispatch[SSH2_MSG_SERVICE_REQUEST] = ssh2_msg_unexpected;
10753 ssh->packet_dispatch[SSH2_MSG_SERVICE_ACCEPT] = ssh2_msg_unexpected;
10754 ssh->packet_dispatch[SSH2_MSG_KEXINIT] = ssh2_msg_transport;
10755 ssh->packet_dispatch[SSH2_MSG_NEWKEYS] = ssh2_msg_transport;
10756 ssh->packet_dispatch[SSH2_MSG_KEXDH_INIT] = ssh2_msg_transport;
10757 ssh->packet_dispatch[SSH2_MSG_KEXDH_REPLY] = ssh2_msg_transport;
10758 /* ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_REQUEST] = ssh2_msg_transport; duplicate case value */
10759 /* ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_GROUP] = ssh2_msg_transport; duplicate case value */
10760 ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_INIT] = ssh2_msg_transport;
10761 ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_REPLY] = ssh2_msg_transport;
10762 ssh->packet_dispatch[SSH2_MSG_USERAUTH_REQUEST] = ssh2_msg_unexpected;
10763 ssh->packet_dispatch[SSH2_MSG_USERAUTH_FAILURE] = ssh2_msg_unexpected;
10764 ssh->packet_dispatch[SSH2_MSG_USERAUTH_SUCCESS] = ssh2_msg_unexpected;
10765 ssh->packet_dispatch[SSH2_MSG_USERAUTH_BANNER] = ssh2_msg_unexpected;
10766 ssh->packet_dispatch[SSH2_MSG_USERAUTH_PK_OK] = ssh2_msg_unexpected;
10767 /* ssh->packet_dispatch[SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ] = ssh2_msg_unexpected; duplicate case value */
10768 /* ssh->packet_dispatch[SSH2_MSG_USERAUTH_INFO_REQUEST] = ssh2_msg_unexpected; duplicate case value */
10769 ssh->packet_dispatch[SSH2_MSG_USERAUTH_INFO_RESPONSE] = ssh2_msg_unexpected;
10770 ssh->packet_dispatch[SSH2_MSG_GLOBAL_REQUEST] = ssh2_msg_unexpected;
10771 ssh->packet_dispatch[SSH2_MSG_REQUEST_SUCCESS] = ssh2_msg_unexpected;
10772 ssh->packet_dispatch[SSH2_MSG_REQUEST_FAILURE] = ssh2_msg_unexpected;
10773 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN] = ssh2_msg_unexpected;
10774 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_CONFIRMATION] = ssh2_msg_unexpected;
10775 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_FAILURE] = ssh2_msg_unexpected;
10776 ssh->packet_dispatch[SSH2_MSG_CHANNEL_WINDOW_ADJUST] = ssh2_msg_unexpected;
10777 ssh->packet_dispatch[SSH2_MSG_CHANNEL_DATA] = ssh2_msg_unexpected;
10778 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EXTENDED_DATA] = ssh2_msg_unexpected;
10779 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EOF] = ssh2_msg_unexpected;
10780 ssh->packet_dispatch[SSH2_MSG_CHANNEL_CLOSE] = ssh2_msg_unexpected;
10781 ssh->packet_dispatch[SSH2_MSG_CHANNEL_REQUEST] = ssh2_msg_unexpected;
10782 ssh->packet_dispatch[SSH2_MSG_CHANNEL_SUCCESS] = ssh2_msg_unexpected;
10783 ssh->packet_dispatch[SSH2_MSG_CHANNEL_FAILURE] = ssh2_msg_unexpected;
10786 * These messages have a special handler from the start.
10788 ssh->packet_dispatch[SSH2_MSG_DISCONNECT] = ssh2_msg_disconnect;
10789 ssh->packet_dispatch[SSH2_MSG_IGNORE] = ssh_msg_ignore; /* shared with SSH-1 */
10790 ssh->packet_dispatch[SSH2_MSG_DEBUG] = ssh2_msg_debug;
10793 static void ssh2_bare_connection_protocol_setup(Ssh ssh)
10798 * Most messages cause SSH2_MSG_UNIMPLEMENTED.
10800 for (i = 0; i < 256; i++)
10801 ssh->packet_dispatch[i] = ssh2_msg_something_unimplemented;
10804 * Initially, we set all ssh-connection messages to 'unexpected';
10805 * do_ssh2_authconn will fill things in properly. We also handle a
10806 * couple of messages from the transport protocol which aren't
10807 * related to key exchange (UNIMPLEMENTED, IGNORE, DEBUG,
10810 ssh->packet_dispatch[SSH2_MSG_GLOBAL_REQUEST] = ssh2_msg_unexpected;
10811 ssh->packet_dispatch[SSH2_MSG_REQUEST_SUCCESS] = ssh2_msg_unexpected;
10812 ssh->packet_dispatch[SSH2_MSG_REQUEST_FAILURE] = ssh2_msg_unexpected;
10813 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN] = ssh2_msg_unexpected;
10814 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_CONFIRMATION] = ssh2_msg_unexpected;
10815 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_FAILURE] = ssh2_msg_unexpected;
10816 ssh->packet_dispatch[SSH2_MSG_CHANNEL_WINDOW_ADJUST] = ssh2_msg_unexpected;
10817 ssh->packet_dispatch[SSH2_MSG_CHANNEL_DATA] = ssh2_msg_unexpected;
10818 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EXTENDED_DATA] = ssh2_msg_unexpected;
10819 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EOF] = ssh2_msg_unexpected;
10820 ssh->packet_dispatch[SSH2_MSG_CHANNEL_CLOSE] = ssh2_msg_unexpected;
10821 ssh->packet_dispatch[SSH2_MSG_CHANNEL_REQUEST] = ssh2_msg_unexpected;
10822 ssh->packet_dispatch[SSH2_MSG_CHANNEL_SUCCESS] = ssh2_msg_unexpected;
10823 ssh->packet_dispatch[SSH2_MSG_CHANNEL_FAILURE] = ssh2_msg_unexpected;
10825 ssh->packet_dispatch[SSH2_MSG_UNIMPLEMENTED] = ssh2_msg_unexpected;
10828 * These messages have a special handler from the start.
10830 ssh->packet_dispatch[SSH2_MSG_DISCONNECT] = ssh2_msg_disconnect;
10831 ssh->packet_dispatch[SSH2_MSG_IGNORE] = ssh_msg_ignore;
10832 ssh->packet_dispatch[SSH2_MSG_DEBUG] = ssh2_msg_debug;
10835 static void ssh2_timer(void *ctx, unsigned long now)
10837 Ssh ssh = (Ssh)ctx;
10839 if (ssh->state == SSH_STATE_CLOSED)
10842 if (!ssh->kex_in_progress && !ssh->bare_connection &&
10843 conf_get_int(ssh->conf, CONF_ssh_rekey_time) != 0 &&
10844 now == ssh->next_rekey) {
10845 do_ssh2_transport(ssh, "timeout", -1, NULL);
10849 static void ssh2_protocol(Ssh ssh, const void *vin, int inlen,
10850 struct Packet *pktin)
10852 const unsigned char *in = (const unsigned char *)vin;
10853 if (ssh->state == SSH_STATE_CLOSED)
10857 ssh->incoming_data_size += pktin->encrypted_len;
10858 if (!ssh->kex_in_progress &&
10859 ssh->max_data_size != 0 &&
10860 ssh->incoming_data_size > ssh->max_data_size)
10861 do_ssh2_transport(ssh, "too much data received", -1, NULL);
10865 ssh->packet_dispatch[pktin->type](ssh, pktin);
10866 else if (!ssh->protocol_initial_phase_done)
10867 do_ssh2_transport(ssh, in, inlen, pktin);
10869 do_ssh2_authconn(ssh, in, inlen, pktin);
10872 static void ssh2_bare_connection_protocol(Ssh ssh, const void *vin, int inlen,
10873 struct Packet *pktin)
10875 const unsigned char *in = (const unsigned char *)vin;
10876 if (ssh->state == SSH_STATE_CLOSED)
10880 ssh->packet_dispatch[pktin->type](ssh, pktin);
10882 do_ssh2_authconn(ssh, in, inlen, pktin);
10885 static void ssh_cache_conf_values(Ssh ssh)
10887 ssh->logomitdata = conf_get_int(ssh->conf, CONF_logomitdata);
10891 * Called to set up the connection.
10893 * Returns an error message, or NULL on success.
10895 static const char *ssh_init(void *frontend_handle, void **backend_handle,
10897 const char *host, int port, char **realhost,
10898 int nodelay, int keepalive)
10903 ssh = snew(struct ssh_tag);
10904 ssh->conf = conf_copy(conf);
10905 ssh_cache_conf_values(ssh);
10906 ssh->version = 0; /* when not ready yet */
10908 ssh->cipher = NULL;
10909 ssh->v1_cipher_ctx = NULL;
10910 ssh->crcda_ctx = NULL;
10911 ssh->cscipher = NULL;
10912 ssh->cs_cipher_ctx = NULL;
10913 ssh->sccipher = NULL;
10914 ssh->sc_cipher_ctx = NULL;
10916 ssh->cs_mac_ctx = NULL;
10918 ssh->sc_mac_ctx = NULL;
10919 ssh->cscomp = NULL;
10920 ssh->cs_comp_ctx = NULL;
10921 ssh->sccomp = NULL;
10922 ssh->sc_comp_ctx = NULL;
10924 ssh->kex_ctx = NULL;
10925 ssh->hostkey = NULL;
10926 ssh->hostkey_str = NULL;
10927 ssh->exitcode = -1;
10928 ssh->close_expected = FALSE;
10929 ssh->clean_exit = FALSE;
10930 ssh->state = SSH_STATE_PREPACKET;
10931 ssh->size_needed = FALSE;
10932 ssh->eof_needed = FALSE;
10934 ssh->logctx = NULL;
10935 ssh->deferred_send_data = NULL;
10936 ssh->deferred_len = 0;
10937 ssh->deferred_size = 0;
10938 ssh->fallback_cmd = 0;
10939 ssh->pkt_kctx = SSH2_PKTCTX_NOKEX;
10940 ssh->pkt_actx = SSH2_PKTCTX_NOAUTH;
10941 ssh->x11disp = NULL;
10942 ssh->x11auth = NULL;
10943 ssh->x11authtree = newtree234(x11_authcmp);
10944 ssh->v1_compressing = FALSE;
10945 ssh->v2_outgoing_sequence = 0;
10946 ssh->ssh1_rdpkt_crstate = 0;
10947 ssh->ssh2_rdpkt_crstate = 0;
10948 ssh->ssh2_bare_rdpkt_crstate = 0;
10949 ssh->ssh_gotdata_crstate = 0;
10950 ssh->do_ssh1_connection_crstate = 0;
10951 ssh->do_ssh_init_state = NULL;
10952 ssh->do_ssh_connection_init_state = NULL;
10953 ssh->do_ssh1_login_state = NULL;
10954 ssh->do_ssh2_transport_state = NULL;
10955 ssh->do_ssh2_authconn_state = NULL;
10958 ssh->mainchan = NULL;
10959 ssh->throttled_all = 0;
10960 ssh->v1_stdout_throttling = 0;
10962 ssh->queuelen = ssh->queuesize = 0;
10963 ssh->queueing = FALSE;
10964 ssh->qhead = ssh->qtail = NULL;
10965 ssh->deferred_rekey_reason = NULL;
10966 bufchain_init(&ssh->queued_incoming_data);
10967 ssh->frozen = FALSE;
10968 ssh->username = NULL;
10969 ssh->sent_console_eof = FALSE;
10970 ssh->got_pty = FALSE;
10971 ssh->bare_connection = FALSE;
10972 ssh->X11_fwd_enabled = FALSE;
10973 ssh->connshare = NULL;
10974 ssh->attempting_connshare = FALSE;
10976 *backend_handle = ssh;
10979 if (crypto_startup() == 0)
10980 return "Microsoft high encryption pack not installed!";
10983 ssh->frontend = frontend_handle;
10984 ssh->term_width = conf_get_int(ssh->conf, CONF_width);
10985 ssh->term_height = conf_get_int(ssh->conf, CONF_height);
10987 ssh->channels = NULL;
10988 ssh->rportfwds = NULL;
10989 ssh->portfwds = NULL;
10994 ssh->conn_throttle_count = 0;
10995 ssh->overall_bufsize = 0;
10996 ssh->fallback_cmd = 0;
10998 ssh->protocol = NULL;
11000 ssh->protocol_initial_phase_done = FALSE;
11002 ssh->pinger = NULL;
11004 ssh->incoming_data_size = ssh->outgoing_data_size =
11005 ssh->deferred_data_size = 0L;
11006 ssh->max_data_size = parse_blocksize(conf_get_str(ssh->conf,
11007 CONF_ssh_rekey_data));
11008 ssh->kex_in_progress = FALSE;
11011 ssh->gsslibs = NULL;
11014 random_ref(); /* do this now - may be needed by sharing setup code */
11016 p = connect_to_host(ssh, host, port, realhost, nodelay, keepalive);
11025 static void ssh_free(void *handle)
11027 Ssh ssh = (Ssh) handle;
11028 struct ssh_channel *c;
11029 struct ssh_rportfwd *pf;
11030 struct X11FakeAuth *auth;
11032 if (ssh->v1_cipher_ctx)
11033 ssh->cipher->free_context(ssh->v1_cipher_ctx);
11034 if (ssh->cs_cipher_ctx)
11035 ssh->cscipher->free_context(ssh->cs_cipher_ctx);
11036 if (ssh->sc_cipher_ctx)
11037 ssh->sccipher->free_context(ssh->sc_cipher_ctx);
11038 if (ssh->cs_mac_ctx)
11039 ssh->csmac->free_context(ssh->cs_mac_ctx);
11040 if (ssh->sc_mac_ctx)
11041 ssh->scmac->free_context(ssh->sc_mac_ctx);
11042 if (ssh->cs_comp_ctx) {
11044 ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
11046 zlib_compress_cleanup(ssh->cs_comp_ctx);
11048 if (ssh->sc_comp_ctx) {
11050 ssh->sccomp->decompress_cleanup(ssh->sc_comp_ctx);
11052 zlib_decompress_cleanup(ssh->sc_comp_ctx);
11055 dh_cleanup(ssh->kex_ctx);
11056 sfree(ssh->savedhost);
11058 while (ssh->queuelen-- > 0)
11059 ssh_free_packet(ssh->queue[ssh->queuelen]);
11062 while (ssh->qhead) {
11063 struct queued_handler *qh = ssh->qhead;
11064 ssh->qhead = qh->next;
11067 ssh->qhead = ssh->qtail = NULL;
11069 if (ssh->channels) {
11070 while ((c = delpos234(ssh->channels, 0)) != NULL) {
11073 if (c->u.x11.xconn != NULL)
11074 x11_close(c->u.x11.xconn);
11076 case CHAN_SOCKDATA:
11077 case CHAN_SOCKDATA_DORMANT:
11078 if (c->u.pfd.pf != NULL)
11079 pfd_close(c->u.pfd.pf);
11082 if (ssh->version == 2) {
11083 struct outstanding_channel_request *ocr, *nocr;
11084 ocr = c->v.v2.chanreq_head;
11086 ocr->handler(c, NULL, ocr->ctx);
11091 bufchain_clear(&c->v.v2.outbuffer);
11095 freetree234(ssh->channels);
11096 ssh->channels = NULL;
11099 if (ssh->connshare)
11100 sharestate_free(ssh->connshare);
11102 if (ssh->rportfwds) {
11103 while ((pf = delpos234(ssh->rportfwds, 0)) != NULL)
11105 freetree234(ssh->rportfwds);
11106 ssh->rportfwds = NULL;
11108 sfree(ssh->deferred_send_data);
11110 x11_free_display(ssh->x11disp);
11111 while ((auth = delpos234(ssh->x11authtree, 0)) != NULL)
11112 x11_free_fake_auth(auth);
11113 freetree234(ssh->x11authtree);
11114 sfree(ssh->do_ssh_init_state);
11115 sfree(ssh->do_ssh1_login_state);
11116 sfree(ssh->do_ssh2_transport_state);
11117 sfree(ssh->do_ssh2_authconn_state);
11120 sfree(ssh->fullhostname);
11121 sfree(ssh->hostkey_str);
11122 if (ssh->crcda_ctx) {
11123 crcda_free_context(ssh->crcda_ctx);
11124 ssh->crcda_ctx = NULL;
11127 ssh_do_close(ssh, TRUE);
11128 expire_timer_context(ssh);
11130 pinger_free(ssh->pinger);
11131 bufchain_clear(&ssh->queued_incoming_data);
11132 sfree(ssh->username);
11133 conf_free(ssh->conf);
11136 ssh_gss_cleanup(ssh->gsslibs);
11144 * Reconfigure the SSH backend.
11146 static void ssh_reconfig(void *handle, Conf *conf)
11148 Ssh ssh = (Ssh) handle;
11149 const char *rekeying = NULL;
11150 int rekey_mandatory = FALSE;
11151 unsigned long old_max_data_size;
11154 pinger_reconfig(ssh->pinger, ssh->conf, conf);
11156 ssh_setup_portfwd(ssh, conf);
11158 rekey_time = conf_get_int(conf, CONF_ssh_rekey_time);
11159 if (conf_get_int(ssh->conf, CONF_ssh_rekey_time) != rekey_time &&
11161 unsigned long new_next = ssh->last_rekey + rekey_time*60*TICKSPERSEC;
11162 unsigned long now = GETTICKCOUNT();
11164 if (now - ssh->last_rekey > rekey_time*60*TICKSPERSEC) {
11165 rekeying = "timeout shortened";
11167 ssh->next_rekey = schedule_timer(new_next - now, ssh2_timer, ssh);
11171 old_max_data_size = ssh->max_data_size;
11172 ssh->max_data_size = parse_blocksize(conf_get_str(ssh->conf,
11173 CONF_ssh_rekey_data));
11174 if (old_max_data_size != ssh->max_data_size &&
11175 ssh->max_data_size != 0) {
11176 if (ssh->outgoing_data_size > ssh->max_data_size ||
11177 ssh->incoming_data_size > ssh->max_data_size)
11178 rekeying = "data limit lowered";
11181 if (conf_get_int(ssh->conf, CONF_compression) !=
11182 conf_get_int(conf, CONF_compression)) {
11183 rekeying = "compression setting changed";
11184 rekey_mandatory = TRUE;
11187 for (i = 0; i < CIPHER_MAX; i++)
11188 if (conf_get_int_int(ssh->conf, CONF_ssh_cipherlist, i) !=
11189 conf_get_int_int(conf, CONF_ssh_cipherlist, i)) {
11190 rekeying = "cipher settings changed";
11191 rekey_mandatory = TRUE;
11193 if (conf_get_int(ssh->conf, CONF_ssh2_des_cbc) !=
11194 conf_get_int(conf, CONF_ssh2_des_cbc)) {
11195 rekeying = "cipher settings changed";
11196 rekey_mandatory = TRUE;
11199 conf_free(ssh->conf);
11200 ssh->conf = conf_copy(conf);
11201 ssh_cache_conf_values(ssh);
11203 if (!ssh->bare_connection && rekeying) {
11204 if (!ssh->kex_in_progress) {
11205 do_ssh2_transport(ssh, rekeying, -1, NULL);
11206 } else if (rekey_mandatory) {
11207 ssh->deferred_rekey_reason = rekeying;
11213 * Called to send data down the SSH connection.
11215 static int ssh_send(void *handle, const char *buf, int len)
11217 Ssh ssh = (Ssh) handle;
11219 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
11222 ssh->protocol(ssh, (const unsigned char *)buf, len, 0);
11224 return ssh_sendbuffer(ssh);
11228 * Called to query the current amount of buffered stdin data.
11230 static int ssh_sendbuffer(void *handle)
11232 Ssh ssh = (Ssh) handle;
11233 int override_value;
11235 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
11239 * If the SSH socket itself has backed up, add the total backup
11240 * size on that to any individual buffer on the stdin channel.
11242 override_value = 0;
11243 if (ssh->throttled_all)
11244 override_value = ssh->overall_bufsize;
11246 if (ssh->version == 1) {
11247 return override_value;
11248 } else if (ssh->version == 2) {
11249 if (!ssh->mainchan)
11250 return override_value;
11252 return (override_value +
11253 bufchain_size(&ssh->mainchan->v.v2.outbuffer));
11260 * Called to set the size of the window from SSH's POV.
11262 static void ssh_size(void *handle, int width, int height)
11264 Ssh ssh = (Ssh) handle;
11265 struct Packet *pktout;
11267 ssh->term_width = width;
11268 ssh->term_height = height;
11270 switch (ssh->state) {
11271 case SSH_STATE_BEFORE_SIZE:
11272 case SSH_STATE_PREPACKET:
11273 case SSH_STATE_CLOSED:
11274 break; /* do nothing */
11275 case SSH_STATE_INTERMED:
11276 ssh->size_needed = TRUE; /* buffer for later */
11278 case SSH_STATE_SESSION:
11279 if (!conf_get_int(ssh->conf, CONF_nopty)) {
11280 if (ssh->version == 1) {
11281 send_packet(ssh, SSH1_CMSG_WINDOW_SIZE,
11282 PKT_INT, ssh->term_height,
11283 PKT_INT, ssh->term_width,
11284 PKT_INT, 0, PKT_INT, 0, PKT_END);
11285 } else if (ssh->mainchan) {
11286 pktout = ssh2_chanreq_init(ssh->mainchan, "window-change",
11288 ssh2_pkt_adduint32(pktout, ssh->term_width);
11289 ssh2_pkt_adduint32(pktout, ssh->term_height);
11290 ssh2_pkt_adduint32(pktout, 0);
11291 ssh2_pkt_adduint32(pktout, 0);
11292 ssh2_pkt_send(ssh, pktout);
11300 * Return a list of the special codes that make sense in this
11303 static const struct telnet_special *ssh_get_specials(void *handle)
11305 static const struct telnet_special ssh1_ignore_special[] = {
11306 {"IGNORE message", TS_NOP}
11308 static const struct telnet_special ssh2_ignore_special[] = {
11309 {"IGNORE message", TS_NOP},
11311 static const struct telnet_special ssh2_rekey_special[] = {
11312 {"Repeat key exchange", TS_REKEY},
11314 static const struct telnet_special ssh2_session_specials[] = {
11317 /* These are the signal names defined by RFC 4254.
11318 * They include all the ISO C signals, but are a subset of the POSIX
11319 * required signals. */
11320 {"SIGINT (Interrupt)", TS_SIGINT},
11321 {"SIGTERM (Terminate)", TS_SIGTERM},
11322 {"SIGKILL (Kill)", TS_SIGKILL},
11323 {"SIGQUIT (Quit)", TS_SIGQUIT},
11324 {"SIGHUP (Hangup)", TS_SIGHUP},
11325 {"More signals", TS_SUBMENU},
11326 {"SIGABRT", TS_SIGABRT}, {"SIGALRM", TS_SIGALRM},
11327 {"SIGFPE", TS_SIGFPE}, {"SIGILL", TS_SIGILL},
11328 {"SIGPIPE", TS_SIGPIPE}, {"SIGSEGV", TS_SIGSEGV},
11329 {"SIGUSR1", TS_SIGUSR1}, {"SIGUSR2", TS_SIGUSR2},
11330 {NULL, TS_EXITMENU}
11332 static const struct telnet_special specials_end[] = {
11333 {NULL, TS_EXITMENU}
11335 /* XXX review this length for any changes: */
11336 static struct telnet_special ssh_specials[lenof(ssh2_ignore_special) +
11337 lenof(ssh2_rekey_special) +
11338 lenof(ssh2_session_specials) +
11339 lenof(specials_end)];
11340 Ssh ssh = (Ssh) handle;
11342 #define ADD_SPECIALS(name) \
11344 assert((i + lenof(name)) <= lenof(ssh_specials)); \
11345 memcpy(&ssh_specials[i], name, sizeof name); \
11346 i += lenof(name); \
11349 if (ssh->version == 1) {
11350 /* Don't bother offering IGNORE if we've decided the remote
11351 * won't cope with it, since we wouldn't bother sending it if
11353 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE))
11354 ADD_SPECIALS(ssh1_ignore_special);
11355 } else if (ssh->version == 2) {
11356 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH2_IGNORE))
11357 ADD_SPECIALS(ssh2_ignore_special);
11358 if (!(ssh->remote_bugs & BUG_SSH2_REKEY) && !ssh->bare_connection)
11359 ADD_SPECIALS(ssh2_rekey_special);
11361 ADD_SPECIALS(ssh2_session_specials);
11362 } /* else we're not ready yet */
11365 ADD_SPECIALS(specials_end);
11366 return ssh_specials;
11370 #undef ADD_SPECIALS
11374 * Send special codes. TS_EOF is useful for `plink', so you
11375 * can send an EOF and collect resulting output (e.g. `plink
11378 static void ssh_special(void *handle, Telnet_Special code)
11380 Ssh ssh = (Ssh) handle;
11381 struct Packet *pktout;
11383 if (code == TS_EOF) {
11384 if (ssh->state != SSH_STATE_SESSION) {
11386 * Buffer the EOF in case we are pre-SESSION, so we can
11387 * send it as soon as we reach SESSION.
11389 if (code == TS_EOF)
11390 ssh->eof_needed = TRUE;
11393 if (ssh->version == 1) {
11394 send_packet(ssh, SSH1_CMSG_EOF, PKT_END);
11395 } else if (ssh->mainchan) {
11396 sshfwd_write_eof(ssh->mainchan);
11397 ssh->send_ok = 0; /* now stop trying to read from stdin */
11399 logevent("Sent EOF message");
11400 } else if (code == TS_PING || code == TS_NOP) {
11401 if (ssh->state == SSH_STATE_CLOSED
11402 || ssh->state == SSH_STATE_PREPACKET) return;
11403 if (ssh->version == 1) {
11404 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE))
11405 send_packet(ssh, SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
11407 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH2_IGNORE)) {
11408 pktout = ssh2_pkt_init(SSH2_MSG_IGNORE);
11409 ssh2_pkt_addstring_start(pktout);
11410 ssh2_pkt_send_noqueue(ssh, pktout);
11413 } else if (code == TS_REKEY) {
11414 if (!ssh->kex_in_progress && !ssh->bare_connection &&
11415 ssh->version == 2) {
11416 do_ssh2_transport(ssh, "at user request", -1, NULL);
11418 } else if (code == TS_BRK) {
11419 if (ssh->state == SSH_STATE_CLOSED
11420 || ssh->state == SSH_STATE_PREPACKET) return;
11421 if (ssh->version == 1) {
11422 logevent("Unable to send BREAK signal in SSH-1");
11423 } else if (ssh->mainchan) {
11424 pktout = ssh2_chanreq_init(ssh->mainchan, "break", NULL, NULL);
11425 ssh2_pkt_adduint32(pktout, 0); /* default break length */
11426 ssh2_pkt_send(ssh, pktout);
11429 /* Is is a POSIX signal? */
11430 const char *signame = NULL;
11431 if (code == TS_SIGABRT) signame = "ABRT";
11432 if (code == TS_SIGALRM) signame = "ALRM";
11433 if (code == TS_SIGFPE) signame = "FPE";
11434 if (code == TS_SIGHUP) signame = "HUP";
11435 if (code == TS_SIGILL) signame = "ILL";
11436 if (code == TS_SIGINT) signame = "INT";
11437 if (code == TS_SIGKILL) signame = "KILL";
11438 if (code == TS_SIGPIPE) signame = "PIPE";
11439 if (code == TS_SIGQUIT) signame = "QUIT";
11440 if (code == TS_SIGSEGV) signame = "SEGV";
11441 if (code == TS_SIGTERM) signame = "TERM";
11442 if (code == TS_SIGUSR1) signame = "USR1";
11443 if (code == TS_SIGUSR2) signame = "USR2";
11444 /* The SSH-2 protocol does in principle support arbitrary named
11445 * signals, including signame@domain, but we don't support those. */
11447 /* It's a signal. */
11448 if (ssh->version == 2 && ssh->mainchan) {
11449 pktout = ssh2_chanreq_init(ssh->mainchan, "signal", NULL, NULL);
11450 ssh2_pkt_addstring(pktout, signame);
11451 ssh2_pkt_send(ssh, pktout);
11452 logeventf(ssh, "Sent signal SIG%s", signame);
11455 /* Never heard of it. Do nothing */
11460 void *new_sock_channel(void *handle, struct PortForwarding *pf)
11462 Ssh ssh = (Ssh) handle;
11463 struct ssh_channel *c;
11464 c = snew(struct ssh_channel);
11467 ssh2_channel_init(c);
11468 c->halfopen = TRUE;
11469 c->type = CHAN_SOCKDATA_DORMANT;/* identify channel type */
11471 add234(ssh->channels, c);
11475 unsigned ssh_alloc_sharing_channel(Ssh ssh, void *sharing_ctx)
11477 struct ssh_channel *c;
11478 c = snew(struct ssh_channel);
11481 ssh2_channel_init(c);
11482 c->type = CHAN_SHARING;
11483 c->u.sharing.ctx = sharing_ctx;
11484 add234(ssh->channels, c);
11488 void ssh_delete_sharing_channel(Ssh ssh, unsigned localid)
11490 struct ssh_channel *c;
11492 c = find234(ssh->channels, &localid, ssh_channelfind);
11494 ssh_channel_destroy(c);
11497 void ssh_send_packet_from_downstream(Ssh ssh, unsigned id, int type,
11498 const void *data, int datalen,
11499 const char *additional_log_text)
11501 struct Packet *pkt;
11503 pkt = ssh2_pkt_init(type);
11504 pkt->downstream_id = id;
11505 pkt->additional_log_text = additional_log_text;
11506 ssh2_pkt_adddata(pkt, data, datalen);
11507 ssh2_pkt_send(ssh, pkt);
11511 * This is called when stdout/stderr (the entity to which
11512 * from_backend sends data) manages to clear some backlog.
11514 static void ssh_unthrottle(void *handle, int bufsize)
11516 Ssh ssh = (Ssh) handle;
11519 if (ssh->version == 1) {
11520 if (ssh->v1_stdout_throttling && bufsize < SSH1_BUFFER_LIMIT) {
11521 ssh->v1_stdout_throttling = 0;
11522 ssh_throttle_conn(ssh, -1);
11525 if (ssh->mainchan) {
11526 ssh2_set_window(ssh->mainchan,
11527 bufsize < ssh->mainchan->v.v2.locmaxwin ?
11528 ssh->mainchan->v.v2.locmaxwin - bufsize : 0);
11529 if (ssh_is_simple(ssh))
11532 buflimit = ssh->mainchan->v.v2.locmaxwin;
11533 if (ssh->mainchan->throttling_conn && bufsize <= buflimit) {
11534 ssh->mainchan->throttling_conn = 0;
11535 ssh_throttle_conn(ssh, -1);
11541 * Now process any SSH connection data that was stashed in our
11542 * queue while we were frozen.
11544 ssh_process_queued_incoming_data(ssh);
11547 void ssh_send_port_open(void *channel, const char *hostname, int port,
11550 struct ssh_channel *c = (struct ssh_channel *)channel;
11552 struct Packet *pktout;
11554 logeventf(ssh, "Opening connection to %s:%d for %s", hostname, port, org);
11556 if (ssh->version == 1) {
11557 send_packet(ssh, SSH1_MSG_PORT_OPEN,
11558 PKT_INT, c->localid,
11561 /* PKT_STR, <org:orgport>, */
11564 pktout = ssh2_chanopen_init(c, "direct-tcpip");
11566 char *trimmed_host = host_strduptrim(hostname);
11567 ssh2_pkt_addstring(pktout, trimmed_host);
11568 sfree(trimmed_host);
11570 ssh2_pkt_adduint32(pktout, port);
11572 * We make up values for the originator data; partly it's
11573 * too much hassle to keep track, and partly I'm not
11574 * convinced the server should be told details like that
11575 * about my local network configuration.
11576 * The "originator IP address" is syntactically a numeric
11577 * IP address, and some servers (e.g., Tectia) get upset
11578 * if it doesn't match this syntax.
11580 ssh2_pkt_addstring(pktout, "0.0.0.0");
11581 ssh2_pkt_adduint32(pktout, 0);
11582 ssh2_pkt_send(ssh, pktout);
11586 static int ssh_connected(void *handle)
11588 Ssh ssh = (Ssh) handle;
11589 return ssh->s != NULL;
11592 static int ssh_sendok(void *handle)
11594 Ssh ssh = (Ssh) handle;
11595 return ssh->send_ok;
11598 static int ssh_ldisc(void *handle, int option)
11600 Ssh ssh = (Ssh) handle;
11601 if (option == LD_ECHO)
11602 return ssh->echoing;
11603 if (option == LD_EDIT)
11604 return ssh->editing;
11608 static void ssh_provide_ldisc(void *handle, void *ldisc)
11610 Ssh ssh = (Ssh) handle;
11611 ssh->ldisc = ldisc;
11614 static void ssh_provide_logctx(void *handle, void *logctx)
11616 Ssh ssh = (Ssh) handle;
11617 ssh->logctx = logctx;
11620 static int ssh_return_exitcode(void *handle)
11622 Ssh ssh = (Ssh) handle;
11623 if (ssh->s != NULL)
11626 return (ssh->exitcode >= 0 ? ssh->exitcode : INT_MAX);
11630 * cfg_info for SSH is the protocol running in this session.
11631 * (1 or 2 for the full SSH-1 or SSH-2 protocol; -1 for the bare
11632 * SSH-2 connection protocol, i.e. a downstream; 0 for not-decided-yet.)
11634 static int ssh_cfg_info(void *handle)
11636 Ssh ssh = (Ssh) handle;
11637 if (ssh->version == 0)
11638 return 0; /* don't know yet */
11639 else if (ssh->bare_connection)
11642 return ssh->version;
11646 * Gross hack: pscp will try to start SFTP but fall back to scp1 if
11647 * that fails. This variable is the means by which scp.c can reach
11648 * into the SSH code and find out which one it got.
11650 extern int ssh_fallback_cmd(void *handle)
11652 Ssh ssh = (Ssh) handle;
11653 return ssh->fallback_cmd;
11656 Backend ssh_backend = {
11666 ssh_return_exitcode,
11670 ssh_provide_logctx,
11673 ssh_test_for_upstream,