28 * Packet type contexts, so that ssh2_pkt_type can correctly decode
29 * the ambiguous type numbers back into the correct type strings.
40 SSH2_PKTCTX_PUBLICKEY,
46 static const char *const ssh2_disconnect_reasons[] = {
48 "host not allowed to connect",
50 "key exchange failed",
51 "host authentication failed",
54 "service not available",
55 "protocol version not supported",
56 "host key not verifiable",
59 "too many connections",
60 "auth cancelled by user",
61 "no more auth methods available",
66 * Various remote-bug flags.
68 #define BUG_CHOKES_ON_SSH1_IGNORE 1
69 #define BUG_SSH2_HMAC 2
70 #define BUG_NEEDS_SSH1_PLAIN_PASSWORD 4
71 #define BUG_CHOKES_ON_RSA 8
72 #define BUG_SSH2_RSA_PADDING 16
73 #define BUG_SSH2_DERIVEKEY 32
74 #define BUG_SSH2_REKEY 64
75 #define BUG_SSH2_PK_SESSIONID 128
76 #define BUG_SSH2_MAXPKT 256
77 #define BUG_CHOKES_ON_SSH2_IGNORE 512
78 #define BUG_CHOKES_ON_WINADJ 1024
79 #define BUG_SENDS_LATE_REQUEST_REPLY 2048
80 #define BUG_SSH2_OLDGEX 4096
82 #define DH_MIN_SIZE 1024
83 #define DH_MAX_SIZE 8192
86 * Codes for terminal modes.
87 * Most of these are the same in SSH-1 and SSH-2.
88 * This list is derived from RFC 4254 and
92 const char* const mode;
94 enum { TTY_OP_CHAR, TTY_OP_BOOL } type;
96 /* "V" prefix discarded for special characters relative to SSH specs */
97 { "INTR", 1, TTY_OP_CHAR },
98 { "QUIT", 2, TTY_OP_CHAR },
99 { "ERASE", 3, TTY_OP_CHAR },
100 { "KILL", 4, TTY_OP_CHAR },
101 { "EOF", 5, TTY_OP_CHAR },
102 { "EOL", 6, TTY_OP_CHAR },
103 { "EOL2", 7, TTY_OP_CHAR },
104 { "START", 8, TTY_OP_CHAR },
105 { "STOP", 9, TTY_OP_CHAR },
106 { "SUSP", 10, TTY_OP_CHAR },
107 { "DSUSP", 11, TTY_OP_CHAR },
108 { "REPRINT", 12, TTY_OP_CHAR },
109 { "WERASE", 13, TTY_OP_CHAR },
110 { "LNEXT", 14, TTY_OP_CHAR },
111 { "FLUSH", 15, TTY_OP_CHAR },
112 { "SWTCH", 16, TTY_OP_CHAR },
113 { "STATUS", 17, TTY_OP_CHAR },
114 { "DISCARD", 18, TTY_OP_CHAR },
115 { "IGNPAR", 30, TTY_OP_BOOL },
116 { "PARMRK", 31, TTY_OP_BOOL },
117 { "INPCK", 32, TTY_OP_BOOL },
118 { "ISTRIP", 33, TTY_OP_BOOL },
119 { "INLCR", 34, TTY_OP_BOOL },
120 { "IGNCR", 35, TTY_OP_BOOL },
121 { "ICRNL", 36, TTY_OP_BOOL },
122 { "IUCLC", 37, TTY_OP_BOOL },
123 { "IXON", 38, TTY_OP_BOOL },
124 { "IXANY", 39, TTY_OP_BOOL },
125 { "IXOFF", 40, TTY_OP_BOOL },
126 { "IMAXBEL", 41, TTY_OP_BOOL },
127 { "ISIG", 50, TTY_OP_BOOL },
128 { "ICANON", 51, TTY_OP_BOOL },
129 { "XCASE", 52, TTY_OP_BOOL },
130 { "ECHO", 53, TTY_OP_BOOL },
131 { "ECHOE", 54, TTY_OP_BOOL },
132 { "ECHOK", 55, TTY_OP_BOOL },
133 { "ECHONL", 56, TTY_OP_BOOL },
134 { "NOFLSH", 57, TTY_OP_BOOL },
135 { "TOSTOP", 58, TTY_OP_BOOL },
136 { "IEXTEN", 59, TTY_OP_BOOL },
137 { "ECHOCTL", 60, TTY_OP_BOOL },
138 { "ECHOKE", 61, TTY_OP_BOOL },
139 { "PENDIN", 62, TTY_OP_BOOL }, /* XXX is this a real mode? */
140 { "OPOST", 70, TTY_OP_BOOL },
141 { "OLCUC", 71, TTY_OP_BOOL },
142 { "ONLCR", 72, TTY_OP_BOOL },
143 { "OCRNL", 73, TTY_OP_BOOL },
144 { "ONOCR", 74, TTY_OP_BOOL },
145 { "ONLRET", 75, TTY_OP_BOOL },
146 { "CS7", 90, TTY_OP_BOOL },
147 { "CS8", 91, TTY_OP_BOOL },
148 { "PARENB", 92, TTY_OP_BOOL },
149 { "PARODD", 93, TTY_OP_BOOL }
152 /* Miscellaneous other tty-related constants. */
153 #define SSH_TTY_OP_END 0
154 /* The opcodes for ISPEED/OSPEED differ between SSH-1 and SSH-2. */
155 #define SSH1_TTY_OP_ISPEED 192
156 #define SSH1_TTY_OP_OSPEED 193
157 #define SSH2_TTY_OP_ISPEED 128
158 #define SSH2_TTY_OP_OSPEED 129
160 /* Helper functions for parsing tty-related config. */
161 static unsigned int ssh_tty_parse_specchar(char *s)
166 ret = ctrlparse(s, &next);
167 if (!next) ret = s[0];
169 ret = 255; /* special value meaning "don't set" */
173 static unsigned int ssh_tty_parse_boolean(char *s)
175 if (stricmp(s, "yes") == 0 ||
176 stricmp(s, "on") == 0 ||
177 stricmp(s, "true") == 0 ||
178 stricmp(s, "+") == 0)
180 else if (stricmp(s, "no") == 0 ||
181 stricmp(s, "off") == 0 ||
182 stricmp(s, "false") == 0 ||
183 stricmp(s, "-") == 0)
184 return 0; /* false */
186 return (atoi(s) != 0);
189 #define translate(x) if (type == x) return #x
190 #define translatek(x,ctx) if (type == x && (pkt_kctx == ctx)) return #x
191 #define translatea(x,ctx) if (type == x && (pkt_actx == ctx)) return #x
192 static const char *ssh1_pkt_type(int type)
194 translate(SSH1_MSG_DISCONNECT);
195 translate(SSH1_SMSG_PUBLIC_KEY);
196 translate(SSH1_CMSG_SESSION_KEY);
197 translate(SSH1_CMSG_USER);
198 translate(SSH1_CMSG_AUTH_RSA);
199 translate(SSH1_SMSG_AUTH_RSA_CHALLENGE);
200 translate(SSH1_CMSG_AUTH_RSA_RESPONSE);
201 translate(SSH1_CMSG_AUTH_PASSWORD);
202 translate(SSH1_CMSG_REQUEST_PTY);
203 translate(SSH1_CMSG_WINDOW_SIZE);
204 translate(SSH1_CMSG_EXEC_SHELL);
205 translate(SSH1_CMSG_EXEC_CMD);
206 translate(SSH1_SMSG_SUCCESS);
207 translate(SSH1_SMSG_FAILURE);
208 translate(SSH1_CMSG_STDIN_DATA);
209 translate(SSH1_SMSG_STDOUT_DATA);
210 translate(SSH1_SMSG_STDERR_DATA);
211 translate(SSH1_CMSG_EOF);
212 translate(SSH1_SMSG_EXIT_STATUS);
213 translate(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION);
214 translate(SSH1_MSG_CHANNEL_OPEN_FAILURE);
215 translate(SSH1_MSG_CHANNEL_DATA);
216 translate(SSH1_MSG_CHANNEL_CLOSE);
217 translate(SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION);
218 translate(SSH1_SMSG_X11_OPEN);
219 translate(SSH1_CMSG_PORT_FORWARD_REQUEST);
220 translate(SSH1_MSG_PORT_OPEN);
221 translate(SSH1_CMSG_AGENT_REQUEST_FORWARDING);
222 translate(SSH1_SMSG_AGENT_OPEN);
223 translate(SSH1_MSG_IGNORE);
224 translate(SSH1_CMSG_EXIT_CONFIRMATION);
225 translate(SSH1_CMSG_X11_REQUEST_FORWARDING);
226 translate(SSH1_CMSG_AUTH_RHOSTS_RSA);
227 translate(SSH1_MSG_DEBUG);
228 translate(SSH1_CMSG_REQUEST_COMPRESSION);
229 translate(SSH1_CMSG_AUTH_TIS);
230 translate(SSH1_SMSG_AUTH_TIS_CHALLENGE);
231 translate(SSH1_CMSG_AUTH_TIS_RESPONSE);
232 translate(SSH1_CMSG_AUTH_CCARD);
233 translate(SSH1_SMSG_AUTH_CCARD_CHALLENGE);
234 translate(SSH1_CMSG_AUTH_CCARD_RESPONSE);
237 static const char *ssh2_pkt_type(Pkt_KCtx pkt_kctx, Pkt_ACtx pkt_actx,
240 translatea(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE,SSH2_PKTCTX_GSSAPI);
241 translatea(SSH2_MSG_USERAUTH_GSSAPI_TOKEN,SSH2_PKTCTX_GSSAPI);
242 translatea(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE,SSH2_PKTCTX_GSSAPI);
243 translatea(SSH2_MSG_USERAUTH_GSSAPI_ERROR,SSH2_PKTCTX_GSSAPI);
244 translatea(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK,SSH2_PKTCTX_GSSAPI);
245 translatea(SSH2_MSG_USERAUTH_GSSAPI_MIC, SSH2_PKTCTX_GSSAPI);
246 translate(SSH2_MSG_DISCONNECT);
247 translate(SSH2_MSG_IGNORE);
248 translate(SSH2_MSG_UNIMPLEMENTED);
249 translate(SSH2_MSG_DEBUG);
250 translate(SSH2_MSG_SERVICE_REQUEST);
251 translate(SSH2_MSG_SERVICE_ACCEPT);
252 translate(SSH2_MSG_KEXINIT);
253 translate(SSH2_MSG_NEWKEYS);
254 translatek(SSH2_MSG_KEXDH_INIT, SSH2_PKTCTX_DHGROUP);
255 translatek(SSH2_MSG_KEXDH_REPLY, SSH2_PKTCTX_DHGROUP);
256 translatek(SSH2_MSG_KEX_DH_GEX_REQUEST_OLD, SSH2_PKTCTX_DHGEX);
257 translatek(SSH2_MSG_KEX_DH_GEX_REQUEST, SSH2_PKTCTX_DHGEX);
258 translatek(SSH2_MSG_KEX_DH_GEX_GROUP, SSH2_PKTCTX_DHGEX);
259 translatek(SSH2_MSG_KEX_DH_GEX_INIT, SSH2_PKTCTX_DHGEX);
260 translatek(SSH2_MSG_KEX_DH_GEX_REPLY, SSH2_PKTCTX_DHGEX);
261 translatek(SSH2_MSG_KEXRSA_PUBKEY, SSH2_PKTCTX_RSAKEX);
262 translatek(SSH2_MSG_KEXRSA_SECRET, SSH2_PKTCTX_RSAKEX);
263 translatek(SSH2_MSG_KEXRSA_DONE, SSH2_PKTCTX_RSAKEX);
264 translatek(SSH2_MSG_KEX_ECDH_INIT, SSH2_PKTCTX_ECDHKEX);
265 translatek(SSH2_MSG_KEX_ECDH_REPLY, SSH2_PKTCTX_ECDHKEX);
266 translate(SSH2_MSG_USERAUTH_REQUEST);
267 translate(SSH2_MSG_USERAUTH_FAILURE);
268 translate(SSH2_MSG_USERAUTH_SUCCESS);
269 translate(SSH2_MSG_USERAUTH_BANNER);
270 translatea(SSH2_MSG_USERAUTH_PK_OK, SSH2_PKTCTX_PUBLICKEY);
271 translatea(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, SSH2_PKTCTX_PASSWORD);
272 translatea(SSH2_MSG_USERAUTH_INFO_REQUEST, SSH2_PKTCTX_KBDINTER);
273 translatea(SSH2_MSG_USERAUTH_INFO_RESPONSE, SSH2_PKTCTX_KBDINTER);
274 translate(SSH2_MSG_GLOBAL_REQUEST);
275 translate(SSH2_MSG_REQUEST_SUCCESS);
276 translate(SSH2_MSG_REQUEST_FAILURE);
277 translate(SSH2_MSG_CHANNEL_OPEN);
278 translate(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
279 translate(SSH2_MSG_CHANNEL_OPEN_FAILURE);
280 translate(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
281 translate(SSH2_MSG_CHANNEL_DATA);
282 translate(SSH2_MSG_CHANNEL_EXTENDED_DATA);
283 translate(SSH2_MSG_CHANNEL_EOF);
284 translate(SSH2_MSG_CHANNEL_CLOSE);
285 translate(SSH2_MSG_CHANNEL_REQUEST);
286 translate(SSH2_MSG_CHANNEL_SUCCESS);
287 translate(SSH2_MSG_CHANNEL_FAILURE);
293 /* Enumeration values for fields in SSH-1 packets */
295 PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR, PKT_BIGNUM,
299 * Coroutine mechanics for the sillier bits of the code. If these
300 * macros look impenetrable to you, you might find it helpful to
303 * http://www.chiark.greenend.org.uk/~sgtatham/coroutines.html
305 * which explains the theory behind these macros.
307 * In particular, if you are getting `case expression not constant'
308 * errors when building with MS Visual Studio, this is because MS's
309 * Edit and Continue debugging feature causes their compiler to
310 * violate ANSI C. To disable Edit and Continue debugging:
312 * - right-click ssh.c in the FileView
314 * - select the C/C++ tab and the General category
315 * - under `Debug info:', select anything _other_ than `Program
316 * Database for Edit and Continue'.
318 #define crBegin(v) { int *crLine = &v; switch(v) { case 0:;
319 #define crBeginState crBegin(s->crLine)
320 #define crStateP(t, v) \
322 if (!(v)) { s = (v) = snew(struct t); s->crLine = 0; } \
324 #define crState(t) crStateP(t, ssh->t)
325 #define crFinish(z) } *crLine = 0; return (z); }
326 #define crFinishV } *crLine = 0; return; }
327 #define crFinishFree(z) } sfree(s); return (z); }
328 #define crFinishFreeV } sfree(s); return; }
329 #define crReturn(z) \
331 *crLine =__LINE__; return (z); case __LINE__:;\
335 *crLine=__LINE__; return; case __LINE__:;\
337 #define crStop(z) do{ *crLine = 0; return (z); }while(0)
338 #define crStopV do{ *crLine = 0; return; }while(0)
339 #define crWaitUntil(c) do { crReturn(0); } while (!(c))
340 #define crWaitUntilV(c) do { crReturnV; } while (!(c))
344 static struct Packet *ssh1_pkt_init(int pkt_type);
345 static struct Packet *ssh2_pkt_init(int pkt_type);
346 static void ssh_pkt_ensure(struct Packet *, int length);
347 static void ssh_pkt_adddata(struct Packet *, const void *data, int len);
348 static void ssh_pkt_addbyte(struct Packet *, unsigned char value);
349 static void ssh2_pkt_addbool(struct Packet *, unsigned char value);
350 static void ssh_pkt_adduint32(struct Packet *, unsigned long value);
351 static void ssh_pkt_addstring_start(struct Packet *);
352 static void ssh_pkt_addstring_str(struct Packet *, const char *data);
353 static void ssh_pkt_addstring_data(struct Packet *, const char *data, int len);
354 static void ssh_pkt_addstring(struct Packet *, const char *data);
355 static unsigned char *ssh2_mpint_fmt(Bignum b, int *len);
356 static void ssh1_pkt_addmp(struct Packet *, Bignum b);
357 static void ssh2_pkt_addmp(struct Packet *, Bignum b);
358 static int ssh2_pkt_construct(Ssh, struct Packet *);
359 static void ssh2_pkt_send(Ssh, struct Packet *);
360 static void ssh2_pkt_send_noqueue(Ssh, struct Packet *);
361 static int do_ssh1_login(Ssh ssh, const unsigned char *in, int inlen,
362 struct Packet *pktin);
363 static void do_ssh2_authconn(Ssh ssh, const unsigned char *in, int inlen,
364 struct Packet *pktin);
365 static void ssh2_channel_check_close(struct ssh_channel *c);
366 static void ssh_channel_destroy(struct ssh_channel *c);
367 static void ssh2_msg_something_unimplemented(Ssh ssh, struct Packet *pktin);
370 * Buffer management constants. There are several of these for
371 * various different purposes:
373 * - SSH1_BUFFER_LIMIT is the amount of backlog that must build up
374 * on a local data stream before we throttle the whole SSH
375 * connection (in SSH-1 only). Throttling the whole connection is
376 * pretty drastic so we set this high in the hope it won't
379 * - SSH_MAX_BACKLOG is the amount of backlog that must build up
380 * on the SSH connection itself before we defensively throttle
381 * _all_ local data streams. This is pretty drastic too (though
382 * thankfully unlikely in SSH-2 since the window mechanism should
383 * ensure that the server never has any need to throttle its end
384 * of the connection), so we set this high as well.
386 * - OUR_V2_WINSIZE is the maximum window size we present on SSH-2
389 * - OUR_V2_BIGWIN is the window size we advertise for the only
390 * channel in a simple connection. It must be <= INT_MAX.
392 * - OUR_V2_MAXPKT is the official "maximum packet size" we send
393 * to the remote side. This actually has nothing to do with the
394 * size of the _packet_, but is instead a limit on the amount
395 * of data we're willing to receive in a single SSH2 channel
398 * - OUR_V2_PACKETLIMIT is actually the maximum size of SSH
399 * _packet_ we're prepared to cope with. It must be a multiple
400 * of the cipher block size, and must be at least 35000.
403 #define SSH1_BUFFER_LIMIT 32768
404 #define SSH_MAX_BACKLOG 32768
405 #define OUR_V2_WINSIZE 16384
406 #define OUR_V2_BIGWIN 0x7fffffff
407 #define OUR_V2_MAXPKT 0x4000UL
408 #define OUR_V2_PACKETLIMIT 0x9000UL
410 const static struct ssh_signkey *hostkey_algs[] = {
412 &ssh_ecdsa_nistp256, &ssh_ecdsa_nistp384, &ssh_ecdsa_nistp521,
416 const static struct ssh_mac *macs[] = {
417 &ssh_hmac_sha256, &ssh_hmac_sha1, &ssh_hmac_sha1_96, &ssh_hmac_md5
419 const static struct ssh_mac *buggymacs[] = {
420 &ssh_hmac_sha1_buggy, &ssh_hmac_sha1_96_buggy, &ssh_hmac_md5
423 static void *ssh_comp_none_init(void)
427 static void ssh_comp_none_cleanup(void *handle)
430 static int ssh_comp_none_block(void *handle, unsigned char *block, int len,
431 unsigned char **outblock, int *outlen)
435 static int ssh_comp_none_disable(void *handle)
439 const static struct ssh_compress ssh_comp_none = {
441 ssh_comp_none_init, ssh_comp_none_cleanup, ssh_comp_none_block,
442 ssh_comp_none_init, ssh_comp_none_cleanup, ssh_comp_none_block,
443 ssh_comp_none_disable, NULL
445 extern const struct ssh_compress ssh_zlib;
446 const static struct ssh_compress *compressions[] = {
447 &ssh_zlib, &ssh_comp_none
450 enum { /* channel types */
455 CHAN_SOCKDATA_DORMANT, /* one the remote hasn't confirmed */
457 * CHAN_SHARING indicates a channel which is tracked here on
458 * behalf of a connection-sharing downstream. We do almost nothing
459 * with these channels ourselves: all messages relating to them
460 * get thrown straight to sshshare.c and passed on almost
461 * unmodified to downstream.
465 * CHAN_ZOMBIE is used to indicate a channel for which we've
466 * already destroyed the local data source: for instance, if a
467 * forwarded port experiences a socket error on the local side, we
468 * immediately destroy its local socket and turn the SSH channel
474 typedef void (*handler_fn_t)(Ssh ssh, struct Packet *pktin);
475 typedef void (*chandler_fn_t)(Ssh ssh, struct Packet *pktin, void *ctx);
476 typedef void (*cchandler_fn_t)(struct ssh_channel *, struct Packet *, void *);
479 * Each channel has a queue of outstanding CHANNEL_REQUESTS and their
482 struct outstanding_channel_request {
483 cchandler_fn_t handler;
485 struct outstanding_channel_request *next;
489 * 2-3-4 tree storing channels.
492 Ssh ssh; /* pointer back to main context */
493 unsigned remoteid, localid;
495 /* True if we opened this channel but server hasn't confirmed. */
498 * In SSH-1, this value contains four bits:
500 * 1 We have sent SSH1_MSG_CHANNEL_CLOSE.
501 * 2 We have sent SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION.
502 * 4 We have received SSH1_MSG_CHANNEL_CLOSE.
503 * 8 We have received SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION.
505 * A channel is completely finished with when all four bits are set.
507 * In SSH-2, the four bits mean:
509 * 1 We have sent SSH2_MSG_CHANNEL_EOF.
510 * 2 We have sent SSH2_MSG_CHANNEL_CLOSE.
511 * 4 We have received SSH2_MSG_CHANNEL_EOF.
512 * 8 We have received SSH2_MSG_CHANNEL_CLOSE.
514 * A channel is completely finished with when we have both sent
515 * and received CLOSE.
517 * The symbolic constants below use the SSH-2 terminology, which
518 * is a bit confusing in SSH-1, but we have to use _something_.
520 #define CLOSES_SENT_EOF 1
521 #define CLOSES_SENT_CLOSE 2
522 #define CLOSES_RCVD_EOF 4
523 #define CLOSES_RCVD_CLOSE 8
527 * This flag indicates that an EOF is pending on the outgoing side
528 * of the channel: that is, wherever we're getting the data for
529 * this channel has sent us some data followed by EOF. We can't
530 * actually send the EOF until we've finished sending the data, so
531 * we set this flag instead to remind us to do so once our buffer
537 * True if this channel is causing the underlying connection to be
542 struct ssh2_data_channel {
544 unsigned remwindow, remmaxpkt;
545 /* locwindow is signed so we can cope with excess data. */
546 int locwindow, locmaxwin;
548 * remlocwin is the amount of local window that we think
549 * the remote end had available to it after it sent the
550 * last data packet or window adjust ack.
554 * These store the list of channel requests that haven't
557 struct outstanding_channel_request *chanreq_head, *chanreq_tail;
558 enum { THROTTLED, UNTHROTTLING, UNTHROTTLED } throttle_state;
562 struct ssh_agent_channel {
563 unsigned char *message;
564 unsigned char msglen[4];
565 unsigned lensofar, totallen;
566 int outstanding_requests;
568 struct ssh_x11_channel {
569 struct X11Connection *xconn;
572 struct ssh_pfd_channel {
573 struct PortForwarding *pf;
575 struct ssh_sharing_channel {
582 * 2-3-4 tree storing remote->local port forwardings. SSH-1 and SSH-2
583 * use this structure in different ways, reflecting SSH-2's
584 * altogether saner approach to port forwarding.
586 * In SSH-1, you arrange a remote forwarding by sending the server
587 * the remote port number, and the local destination host:port.
588 * When a connection comes in, the server sends you back that
589 * host:port pair, and you connect to it. This is a ready-made
590 * security hole if you're not on the ball: a malicious server
591 * could send you back _any_ host:port pair, so if you trustingly
592 * connect to the address it gives you then you've just opened the
593 * entire inside of your corporate network just by connecting
594 * through it to a dodgy SSH server. Hence, we must store a list of
595 * host:port pairs we _are_ trying to forward to, and reject a
596 * connection request from the server if it's not in the list.
598 * In SSH-2, each side of the connection minds its own business and
599 * doesn't send unnecessary information to the other. You arrange a
600 * remote forwarding by sending the server just the remote port
601 * number. When a connection comes in, the server tells you which
602 * of its ports was connected to; and _you_ have to remember what
603 * local host:port pair went with that port number.
605 * Hence, in SSH-1 this structure is indexed by destination
606 * host:port pair, whereas in SSH-2 it is indexed by source port.
608 struct ssh_portfwd; /* forward declaration */
610 struct ssh_rportfwd {
611 unsigned sport, dport;
615 struct ssh_portfwd *pfrec;
618 static void free_rportfwd(struct ssh_rportfwd *pf)
621 sfree(pf->sportdesc);
629 * Separately to the rportfwd tree (which is for looking up port
630 * open requests from the server), a tree of _these_ structures is
631 * used to keep track of all the currently open port forwardings,
632 * so that we can reconfigure in mid-session if the user requests
636 enum { DESTROY, KEEP, CREATE } status;
638 unsigned sport, dport;
641 struct ssh_rportfwd *remote;
643 struct PortListener *local;
645 #define free_portfwd(pf) ( \
646 ((pf) ? (sfree((pf)->saddr), sfree((pf)->daddr), \
647 sfree((pf)->sserv), sfree((pf)->dserv)) : (void)0 ), sfree(pf) )
650 long length; /* length of packet: see below */
651 long forcepad; /* SSH-2: force padding to at least this length */
652 int type; /* only used for incoming packets */
653 unsigned long sequence; /* SSH-2 incoming sequence number */
654 unsigned char *data; /* allocated storage */
655 unsigned char *body; /* offset of payload within `data' */
656 long savedpos; /* dual-purpose saved packet position: see below */
657 long maxlen; /* amount of storage allocated for `data' */
658 long encrypted_len; /* for SSH-2 total-size counting */
661 * A note on the 'length' and 'savedpos' fields above.
663 * Incoming packets are set up so that pkt->length is measured
664 * relative to pkt->body, which itself points to a few bytes after
665 * pkt->data (skipping some uninteresting header fields including
666 * the packet type code). The ssh_pkt_get* functions all expect
667 * this setup, and they also use pkt->savedpos to indicate how far
668 * through the packet being decoded they've got - and that, too,
669 * is an offset from pkt->body rather than pkt->data.
671 * During construction of an outgoing packet, however, pkt->length
672 * is measured relative to the base pointer pkt->data, and
673 * pkt->body is not really used for anything until the packet is
674 * ready for sending. In this mode, pkt->savedpos is reused as a
675 * temporary variable by the addstring functions, which write out
676 * a string length field and then keep going back and updating it
677 * as more data is appended to the subsequent string data field;
678 * pkt->savedpos stores the offset (again relative to pkt->data)
679 * of the start of the string data field.
682 /* Extra metadata used in SSH packet logging mode, allowing us to
683 * log in the packet header line that the packet came from a
684 * connection-sharing downstream and what if anything unusual was
685 * done to it. The additional_log_text field is expected to be a
686 * static string - it will not be freed. */
687 unsigned downstream_id;
688 const char *additional_log_text;
691 static void ssh1_protocol(Ssh ssh, const void *vin, int inlen,
692 struct Packet *pktin);
693 static void ssh2_protocol(Ssh ssh, const void *vin, int inlen,
694 struct Packet *pktin);
695 static void ssh2_bare_connection_protocol(Ssh ssh, const void *vin, int inlen,
696 struct Packet *pktin);
697 static void ssh1_protocol_setup(Ssh ssh);
698 static void ssh2_protocol_setup(Ssh ssh);
699 static void ssh2_bare_connection_protocol_setup(Ssh ssh);
700 static void ssh_size(void *handle, int width, int height);
701 static void ssh_special(void *handle, Telnet_Special);
702 static int ssh2_try_send(struct ssh_channel *c);
703 static void ssh2_add_channel_data(struct ssh_channel *c,
704 const char *buf, int len);
705 static void ssh_throttle_all(Ssh ssh, int enable, int bufsize);
706 static void ssh2_set_window(struct ssh_channel *c, int newwin);
707 static int ssh_sendbuffer(void *handle);
708 static int ssh_do_close(Ssh ssh, int notify_exit);
709 static unsigned long ssh_pkt_getuint32(struct Packet *pkt);
710 static int ssh2_pkt_getbool(struct Packet *pkt);
711 static void ssh_pkt_getstring(struct Packet *pkt, char **p, int *length);
712 static void ssh2_timer(void *ctx, unsigned long now);
713 static void do_ssh2_transport(Ssh ssh, const void *vin, int inlen,
714 struct Packet *pktin);
715 static void ssh2_msg_unexpected(Ssh ssh, struct Packet *pktin);
717 struct rdpkt1_state_tag {
718 long len, pad, biglen, to_read;
719 unsigned long realcrc, gotcrc;
723 struct Packet *pktin;
726 struct rdpkt2_state_tag {
727 long len, pad, payload, packetlen, maclen;
730 unsigned long incoming_sequence;
731 struct Packet *pktin;
734 struct rdpkt2_bare_state_tag {
738 unsigned long incoming_sequence;
739 struct Packet *pktin;
742 struct queued_handler;
743 struct queued_handler {
745 chandler_fn_t handler;
747 struct queued_handler *next;
751 const struct plug_function_table *fn;
752 /* the above field _must_ be first in the structure */
762 unsigned char session_key[32];
764 int v1_remote_protoflags;
765 int v1_local_protoflags;
766 int agentfwd_enabled;
769 const struct ssh_cipher *cipher;
772 const struct ssh2_cipher *cscipher, *sccipher;
773 void *cs_cipher_ctx, *sc_cipher_ctx;
774 const struct ssh_mac *csmac, *scmac;
775 int csmac_etm, scmac_etm;
776 void *cs_mac_ctx, *sc_mac_ctx;
777 const struct ssh_compress *cscomp, *sccomp;
778 void *cs_comp_ctx, *sc_comp_ctx;
779 const struct ssh_kex *kex;
780 const struct ssh_signkey *hostkey;
781 char *hostkey_str; /* string representation, for easy checking in rekeys */
782 unsigned char v2_session_id[SSH2_KEX_MAX_HASH_LEN];
783 int v2_session_id_len;
787 int attempting_connshare;
793 int echoing, editing;
797 int ospeed, ispeed; /* temporaries */
798 int term_width, term_height;
800 tree234 *channels; /* indexed by local id */
801 struct ssh_channel *mainchan; /* primary session channel */
802 int ncmode; /* is primary channel direct-tcpip? */
807 tree234 *rportfwds, *portfwds;
811 SSH_STATE_BEFORE_SIZE,
817 int size_needed, eof_needed;
818 int sent_console_eof;
819 int got_pty; /* affects EOF behaviour on main channel */
821 struct Packet **queue;
822 int queuelen, queuesize;
824 unsigned char *deferred_send_data;
825 int deferred_len, deferred_size;
828 * Gross hack: pscp will try to start SFTP but fall back to
829 * scp1 if that fails. This variable is the means by which
830 * scp.c can reach into the SSH code and find out which one it
835 bufchain banner; /* accumulates banners during do_ssh2_authconn */
840 struct X11Display *x11disp;
841 struct X11FakeAuth *x11auth;
842 tree234 *x11authtree;
845 int conn_throttle_count;
848 int v1_stdout_throttling;
849 unsigned long v2_outgoing_sequence;
851 int ssh1_rdpkt_crstate;
852 int ssh2_rdpkt_crstate;
853 int ssh2_bare_rdpkt_crstate;
854 int ssh_gotdata_crstate;
855 int do_ssh1_connection_crstate;
857 void *do_ssh_init_state;
858 void *do_ssh1_login_state;
859 void *do_ssh2_transport_state;
860 void *do_ssh2_authconn_state;
861 void *do_ssh_connection_init_state;
863 struct rdpkt1_state_tag rdpkt1_state;
864 struct rdpkt2_state_tag rdpkt2_state;
865 struct rdpkt2_bare_state_tag rdpkt2_bare_state;
867 /* SSH-1 and SSH-2 use this for different things, but both use it */
868 int protocol_initial_phase_done;
870 void (*protocol) (Ssh ssh, const void *vin, int inlen,
872 struct Packet *(*s_rdpkt) (Ssh ssh, const unsigned char **data,
874 int (*do_ssh_init)(Ssh ssh, unsigned char c);
877 * We maintain our own copy of a Conf structure here. That way,
878 * when we're passed a new one for reconfiguration, we can check
879 * the differences and potentially reconfigure port forwardings
880 * etc in mid-session.
885 * Values cached out of conf so as to avoid the tree234 lookup
886 * cost every time they're used.
891 * Dynamically allocated username string created during SSH
892 * login. Stored in here rather than in the coroutine state so
893 * that it'll be reliably freed if we shut down the SSH session
894 * at some unexpected moment.
899 * Used to transfer data back from async callbacks.
901 void *agent_response;
902 int agent_response_len;
906 * The SSH connection can be set as `frozen', meaning we are
907 * not currently accepting incoming data from the network. This
908 * is slightly more serious than setting the _socket_ as
909 * frozen, because we may already have had data passed to us
910 * from the network which we need to delay processing until
911 * after the freeze is lifted, so we also need a bufchain to
915 bufchain queued_incoming_data;
918 * Dispatch table for packet types that we may have to deal
921 handler_fn_t packet_dispatch[256];
924 * Queues of one-off handler functions for success/failure
925 * indications from a request.
927 struct queued_handler *qhead, *qtail;
928 handler_fn_t q_saved_handler1, q_saved_handler2;
931 * This module deals with sending keepalives.
936 * Track incoming and outgoing data sizes and time, for
939 unsigned long incoming_data_size, outgoing_data_size, deferred_data_size;
940 unsigned long max_data_size;
942 unsigned long next_rekey, last_rekey;
943 const char *deferred_rekey_reason;
946 * Fully qualified host name, which we need if doing GSSAPI.
952 * GSSAPI libraries for this session.
954 struct ssh_gss_liblist *gsslibs;
958 #define logevent(s) logevent(ssh->frontend, s)
960 /* logevent, only printf-formatted. */
961 static void logeventf(Ssh ssh, const char *fmt, ...)
967 buf = dupvprintf(fmt, ap);
973 static void bomb_out(Ssh ssh, char *text)
975 ssh_do_close(ssh, FALSE);
977 connection_fatal(ssh->frontend, "%s", text);
981 #define bombout(msg) bomb_out(ssh, dupprintf msg)
983 /* Helper function for common bits of parsing ttymodes. */
984 static void parse_ttymodes(Ssh ssh,
985 void (*do_mode)(void *data, char *mode, char *val),
990 for (val = conf_get_str_strs(ssh->conf, CONF_ttymodes, NULL, &key);
992 val = conf_get_str_strs(ssh->conf, CONF_ttymodes, key, &key)) {
994 * val[0] is either 'V', indicating that an explicit value
995 * follows it, or 'A' indicating that we should pass the
996 * value through from the local environment via get_ttymode.
999 val = get_ttymode(ssh->frontend, key);
1001 do_mode(data, key, val);
1005 do_mode(data, key, val + 1); /* skip the 'V' */
1009 static int ssh_channelcmp(void *av, void *bv)
1011 struct ssh_channel *a = (struct ssh_channel *) av;
1012 struct ssh_channel *b = (struct ssh_channel *) bv;
1013 if (a->localid < b->localid)
1015 if (a->localid > b->localid)
1019 static int ssh_channelfind(void *av, void *bv)
1021 unsigned *a = (unsigned *) av;
1022 struct ssh_channel *b = (struct ssh_channel *) bv;
1023 if (*a < b->localid)
1025 if (*a > b->localid)
1030 static int ssh_rportcmp_ssh1(void *av, void *bv)
1032 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
1033 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
1035 if ( (i = strcmp(a->dhost, b->dhost)) != 0)
1036 return i < 0 ? -1 : +1;
1037 if (a->dport > b->dport)
1039 if (a->dport < b->dport)
1044 static int ssh_rportcmp_ssh2(void *av, void *bv)
1046 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
1047 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
1049 if ( (i = strcmp(a->shost, b->shost)) != 0)
1050 return i < 0 ? -1 : +1;
1051 if (a->sport > b->sport)
1053 if (a->sport < b->sport)
1059 * Special form of strcmp which can cope with NULL inputs. NULL is
1060 * defined to sort before even the empty string.
1062 static int nullstrcmp(const char *a, const char *b)
1064 if (a == NULL && b == NULL)
1070 return strcmp(a, b);
1073 static int ssh_portcmp(void *av, void *bv)
1075 struct ssh_portfwd *a = (struct ssh_portfwd *) av;
1076 struct ssh_portfwd *b = (struct ssh_portfwd *) bv;
1078 if (a->type > b->type)
1080 if (a->type < b->type)
1082 if (a->addressfamily > b->addressfamily)
1084 if (a->addressfamily < b->addressfamily)
1086 if ( (i = nullstrcmp(a->saddr, b->saddr)) != 0)
1087 return i < 0 ? -1 : +1;
1088 if (a->sport > b->sport)
1090 if (a->sport < b->sport)
1092 if (a->type != 'D') {
1093 if ( (i = nullstrcmp(a->daddr, b->daddr)) != 0)
1094 return i < 0 ? -1 : +1;
1095 if (a->dport > b->dport)
1097 if (a->dport < b->dport)
1103 static int alloc_channel_id(Ssh ssh)
1105 const unsigned CHANNEL_NUMBER_OFFSET = 256;
1106 unsigned low, high, mid;
1108 struct ssh_channel *c;
1111 * First-fit allocation of channel numbers: always pick the
1112 * lowest unused one. To do this, binary-search using the
1113 * counted B-tree to find the largest channel ID which is in a
1114 * contiguous sequence from the beginning. (Precisely
1115 * everything in that sequence must have ID equal to its tree
1116 * index plus CHANNEL_NUMBER_OFFSET.)
1118 tsize = count234(ssh->channels);
1122 while (high - low > 1) {
1123 mid = (high + low) / 2;
1124 c = index234(ssh->channels, mid);
1125 if (c->localid == mid + CHANNEL_NUMBER_OFFSET)
1126 low = mid; /* this one is fine */
1128 high = mid; /* this one is past it */
1131 * Now low points to either -1, or the tree index of the
1132 * largest ID in the initial sequence.
1135 unsigned i = low + 1 + CHANNEL_NUMBER_OFFSET;
1136 assert(NULL == find234(ssh->channels, &i, ssh_channelfind));
1138 return low + 1 + CHANNEL_NUMBER_OFFSET;
1141 static void c_write_stderr(int trusted, const char *buf, int len)
1144 for (i = 0; i < len; i++)
1145 if (buf[i] != '\r' && (trusted || buf[i] == '\n' || (buf[i] & 0x60)))
1146 fputc(buf[i], stderr);
1149 static void c_write(Ssh ssh, const char *buf, int len)
1151 if (flags & FLAG_STDERR)
1152 c_write_stderr(1, buf, len);
1154 from_backend(ssh->frontend, 1, buf, len);
1157 static void c_write_untrusted(Ssh ssh, const char *buf, int len)
1159 if (flags & FLAG_STDERR)
1160 c_write_stderr(0, buf, len);
1162 from_backend_untrusted(ssh->frontend, buf, len);
1165 static void c_write_str(Ssh ssh, const char *buf)
1167 c_write(ssh, buf, strlen(buf));
1170 static void ssh_free_packet(struct Packet *pkt)
1175 static struct Packet *ssh_new_packet(void)
1177 struct Packet *pkt = snew(struct Packet);
1179 pkt->body = pkt->data = NULL;
1185 static void ssh1_log_incoming_packet(Ssh ssh, struct Packet *pkt)
1188 struct logblank_t blanks[4];
1194 if (ssh->logomitdata &&
1195 (pkt->type == SSH1_SMSG_STDOUT_DATA ||
1196 pkt->type == SSH1_SMSG_STDERR_DATA ||
1197 pkt->type == SSH1_MSG_CHANNEL_DATA)) {
1198 /* "Session data" packets - omit the data string. */
1199 if (pkt->type == SSH1_MSG_CHANNEL_DATA)
1200 ssh_pkt_getuint32(pkt); /* skip channel id */
1201 blanks[nblanks].offset = pkt->savedpos + 4;
1202 blanks[nblanks].type = PKTLOG_OMIT;
1203 ssh_pkt_getstring(pkt, &str, &slen);
1205 blanks[nblanks].len = slen;
1209 log_packet(ssh->logctx, PKT_INCOMING, pkt->type,
1210 ssh1_pkt_type(pkt->type),
1211 pkt->body, pkt->length, nblanks, blanks, NULL,
1215 static void ssh1_log_outgoing_packet(Ssh ssh, struct Packet *pkt)
1218 struct logblank_t blanks[4];
1223 * For outgoing packets, pkt->length represents the length of the
1224 * whole packet starting at pkt->data (including some header), and
1225 * pkt->body refers to the point within that where the log-worthy
1226 * payload begins. However, incoming packets expect pkt->length to
1227 * represent only the payload length (that is, it's measured from
1228 * pkt->body not from pkt->data). Temporarily adjust our outgoing
1229 * packet to conform to the incoming-packet semantics, so that we
1230 * can analyse it with the ssh_pkt_get functions.
1232 pkt->length -= (pkt->body - pkt->data);
1235 if (ssh->logomitdata &&
1236 (pkt->type == SSH1_CMSG_STDIN_DATA ||
1237 pkt->type == SSH1_MSG_CHANNEL_DATA)) {
1238 /* "Session data" packets - omit the data string. */
1239 if (pkt->type == SSH1_MSG_CHANNEL_DATA)
1240 ssh_pkt_getuint32(pkt); /* skip channel id */
1241 blanks[nblanks].offset = pkt->savedpos + 4;
1242 blanks[nblanks].type = PKTLOG_OMIT;
1243 ssh_pkt_getstring(pkt, &str, &slen);
1245 blanks[nblanks].len = slen;
1250 if ((pkt->type == SSH1_CMSG_AUTH_PASSWORD ||
1251 pkt->type == SSH1_CMSG_AUTH_TIS_RESPONSE ||
1252 pkt->type == SSH1_CMSG_AUTH_CCARD_RESPONSE) &&
1253 conf_get_int(ssh->conf, CONF_logomitpass)) {
1254 /* If this is a password or similar packet, blank the password(s). */
1255 blanks[nblanks].offset = 0;
1256 blanks[nblanks].len = pkt->length;
1257 blanks[nblanks].type = PKTLOG_BLANK;
1259 } else if (pkt->type == SSH1_CMSG_X11_REQUEST_FORWARDING &&
1260 conf_get_int(ssh->conf, CONF_logomitpass)) {
1262 * If this is an X forwarding request packet, blank the fake
1265 * Note that while we blank the X authentication data here, we
1266 * don't take any special action to blank the start of an X11
1267 * channel, so using MIT-MAGIC-COOKIE-1 and actually opening
1268 * an X connection without having session blanking enabled is
1269 * likely to leak your cookie into the log.
1272 ssh_pkt_getstring(pkt, &str, &slen);
1273 blanks[nblanks].offset = pkt->savedpos;
1274 blanks[nblanks].type = PKTLOG_BLANK;
1275 ssh_pkt_getstring(pkt, &str, &slen);
1277 blanks[nblanks].len = pkt->savedpos - blanks[nblanks].offset;
1282 log_packet(ssh->logctx, PKT_OUTGOING, pkt->data[12],
1283 ssh1_pkt_type(pkt->data[12]),
1284 pkt->body, pkt->length,
1285 nblanks, blanks, NULL, 0, NULL);
1288 * Undo the above adjustment of pkt->length, to put the packet
1289 * back in the state we found it.
1291 pkt->length += (pkt->body - pkt->data);
1295 * Collect incoming data in the incoming packet buffer.
1296 * Decipher and verify the packet when it is completely read.
1297 * Drop SSH1_MSG_DEBUG and SSH1_MSG_IGNORE packets.
1298 * Update the *data and *datalen variables.
1299 * Return a Packet structure when a packet is completed.
1301 static struct Packet *ssh1_rdpkt(Ssh ssh, const unsigned char **data,
1304 struct rdpkt1_state_tag *st = &ssh->rdpkt1_state;
1306 crBegin(ssh->ssh1_rdpkt_crstate);
1308 st->pktin = ssh_new_packet();
1310 st->pktin->type = 0;
1311 st->pktin->length = 0;
1313 for (st->i = st->len = 0; st->i < 4; st->i++) {
1314 while ((*datalen) == 0)
1316 st->len = (st->len << 8) + **data;
1317 (*data)++, (*datalen)--;
1320 st->pad = 8 - (st->len % 8);
1321 st->biglen = st->len + st->pad;
1322 st->pktin->length = st->len - 5;
1324 if (st->biglen < 0) {
1325 bombout(("Extremely large packet length from server suggests"
1326 " data stream corruption"));
1327 ssh_free_packet(st->pktin);
1331 st->pktin->maxlen = st->biglen;
1332 st->pktin->data = snewn(st->biglen + APIEXTRA, unsigned char);
1334 st->to_read = st->biglen;
1335 st->p = st->pktin->data;
1336 while (st->to_read > 0) {
1337 st->chunk = st->to_read;
1338 while ((*datalen) == 0)
1340 if (st->chunk > (*datalen))
1341 st->chunk = (*datalen);
1342 memcpy(st->p, *data, st->chunk);
1344 *datalen -= st->chunk;
1346 st->to_read -= st->chunk;
1349 if (ssh->cipher && detect_attack(ssh->crcda_ctx, st->pktin->data,
1350 st->biglen, NULL)) {
1351 bombout(("Network attack (CRC compensation) detected!"));
1352 ssh_free_packet(st->pktin);
1357 ssh->cipher->decrypt(ssh->v1_cipher_ctx, st->pktin->data, st->biglen);
1359 st->realcrc = crc32_compute(st->pktin->data, st->biglen - 4);
1360 st->gotcrc = GET_32BIT(st->pktin->data + st->biglen - 4);
1361 if (st->gotcrc != st->realcrc) {
1362 bombout(("Incorrect CRC received on packet"));
1363 ssh_free_packet(st->pktin);
1367 st->pktin->body = st->pktin->data + st->pad + 1;
1369 if (ssh->v1_compressing) {
1370 unsigned char *decompblk;
1372 if (!zlib_decompress_block(ssh->sc_comp_ctx,
1373 st->pktin->body - 1, st->pktin->length + 1,
1374 &decompblk, &decomplen)) {
1375 bombout(("Zlib decompression encountered invalid data"));
1376 ssh_free_packet(st->pktin);
1380 if (st->pktin->maxlen < st->pad + decomplen) {
1381 st->pktin->maxlen = st->pad + decomplen;
1382 st->pktin->data = sresize(st->pktin->data,
1383 st->pktin->maxlen + APIEXTRA,
1385 st->pktin->body = st->pktin->data + st->pad + 1;
1388 memcpy(st->pktin->body - 1, decompblk, decomplen);
1390 st->pktin->length = decomplen - 1;
1393 st->pktin->type = st->pktin->body[-1];
1396 * Now pktin->body and pktin->length identify the semantic content
1397 * of the packet, excluding the initial type byte.
1401 ssh1_log_incoming_packet(ssh, st->pktin);
1403 st->pktin->savedpos = 0;
1405 crFinish(st->pktin);
1408 static void ssh2_log_incoming_packet(Ssh ssh, struct Packet *pkt)
1411 struct logblank_t blanks[4];
1417 if (ssh->logomitdata &&
1418 (pkt->type == SSH2_MSG_CHANNEL_DATA ||
1419 pkt->type == SSH2_MSG_CHANNEL_EXTENDED_DATA)) {
1420 /* "Session data" packets - omit the data string. */
1421 ssh_pkt_getuint32(pkt); /* skip channel id */
1422 if (pkt->type == SSH2_MSG_CHANNEL_EXTENDED_DATA)
1423 ssh_pkt_getuint32(pkt); /* skip extended data type */
1424 blanks[nblanks].offset = pkt->savedpos + 4;
1425 blanks[nblanks].type = PKTLOG_OMIT;
1426 ssh_pkt_getstring(pkt, &str, &slen);
1428 blanks[nblanks].len = slen;
1433 log_packet(ssh->logctx, PKT_INCOMING, pkt->type,
1434 ssh2_pkt_type(ssh->pkt_kctx, ssh->pkt_actx, pkt->type),
1435 pkt->body, pkt->length, nblanks, blanks, &pkt->sequence,
1439 static void ssh2_log_outgoing_packet(Ssh ssh, struct Packet *pkt)
1442 struct logblank_t blanks[4];
1447 * For outgoing packets, pkt->length represents the length of the
1448 * whole packet starting at pkt->data (including some header), and
1449 * pkt->body refers to the point within that where the log-worthy
1450 * payload begins. However, incoming packets expect pkt->length to
1451 * represent only the payload length (that is, it's measured from
1452 * pkt->body not from pkt->data). Temporarily adjust our outgoing
1453 * packet to conform to the incoming-packet semantics, so that we
1454 * can analyse it with the ssh_pkt_get functions.
1456 pkt->length -= (pkt->body - pkt->data);
1459 if (ssh->logomitdata &&
1460 (pkt->type == SSH2_MSG_CHANNEL_DATA ||
1461 pkt->type == SSH2_MSG_CHANNEL_EXTENDED_DATA)) {
1462 /* "Session data" packets - omit the data string. */
1463 ssh_pkt_getuint32(pkt); /* skip channel id */
1464 if (pkt->type == SSH2_MSG_CHANNEL_EXTENDED_DATA)
1465 ssh_pkt_getuint32(pkt); /* skip extended data type */
1466 blanks[nblanks].offset = pkt->savedpos + 4;
1467 blanks[nblanks].type = PKTLOG_OMIT;
1468 ssh_pkt_getstring(pkt, &str, &slen);
1470 blanks[nblanks].len = slen;
1475 if (pkt->type == SSH2_MSG_USERAUTH_REQUEST &&
1476 conf_get_int(ssh->conf, CONF_logomitpass)) {
1477 /* If this is a password packet, blank the password(s). */
1479 ssh_pkt_getstring(pkt, &str, &slen);
1480 ssh_pkt_getstring(pkt, &str, &slen);
1481 ssh_pkt_getstring(pkt, &str, &slen);
1482 if (slen == 8 && !memcmp(str, "password", 8)) {
1483 ssh2_pkt_getbool(pkt);
1484 /* Blank the password field. */
1485 blanks[nblanks].offset = pkt->savedpos;
1486 blanks[nblanks].type = PKTLOG_BLANK;
1487 ssh_pkt_getstring(pkt, &str, &slen);
1489 blanks[nblanks].len = pkt->savedpos - blanks[nblanks].offset;
1491 /* If there's another password field beyond it (change of
1492 * password), blank that too. */
1493 ssh_pkt_getstring(pkt, &str, &slen);
1495 blanks[nblanks-1].len =
1496 pkt->savedpos - blanks[nblanks].offset;
1499 } else if (ssh->pkt_actx == SSH2_PKTCTX_KBDINTER &&
1500 pkt->type == SSH2_MSG_USERAUTH_INFO_RESPONSE &&
1501 conf_get_int(ssh->conf, CONF_logomitpass)) {
1502 /* If this is a keyboard-interactive response packet, blank
1505 ssh_pkt_getuint32(pkt);
1506 blanks[nblanks].offset = pkt->savedpos;
1507 blanks[nblanks].type = PKTLOG_BLANK;
1509 ssh_pkt_getstring(pkt, &str, &slen);
1513 blanks[nblanks].len = pkt->savedpos - blanks[nblanks].offset;
1515 } else if (pkt->type == SSH2_MSG_CHANNEL_REQUEST &&
1516 conf_get_int(ssh->conf, CONF_logomitpass)) {
1518 * If this is an X forwarding request packet, blank the fake
1521 * Note that while we blank the X authentication data here, we
1522 * don't take any special action to blank the start of an X11
1523 * channel, so using MIT-MAGIC-COOKIE-1 and actually opening
1524 * an X connection without having session blanking enabled is
1525 * likely to leak your cookie into the log.
1528 ssh_pkt_getuint32(pkt);
1529 ssh_pkt_getstring(pkt, &str, &slen);
1530 if (slen == 7 && !memcmp(str, "x11-req", 0)) {
1531 ssh2_pkt_getbool(pkt);
1532 ssh2_pkt_getbool(pkt);
1533 ssh_pkt_getstring(pkt, &str, &slen);
1534 blanks[nblanks].offset = pkt->savedpos;
1535 blanks[nblanks].type = PKTLOG_BLANK;
1536 ssh_pkt_getstring(pkt, &str, &slen);
1538 blanks[nblanks].len = pkt->savedpos - blanks[nblanks].offset;
1544 log_packet(ssh->logctx, PKT_OUTGOING, pkt->data[5],
1545 ssh2_pkt_type(ssh->pkt_kctx, ssh->pkt_actx, pkt->data[5]),
1546 pkt->body, pkt->length, nblanks, blanks,
1547 &ssh->v2_outgoing_sequence,
1548 pkt->downstream_id, pkt->additional_log_text);
1551 * Undo the above adjustment of pkt->length, to put the packet
1552 * back in the state we found it.
1554 pkt->length += (pkt->body - pkt->data);
1557 static struct Packet *ssh2_rdpkt(Ssh ssh, const unsigned char **data,
1560 struct rdpkt2_state_tag *st = &ssh->rdpkt2_state;
1562 crBegin(ssh->ssh2_rdpkt_crstate);
1564 st->pktin = ssh_new_packet();
1566 st->pktin->type = 0;
1567 st->pktin->length = 0;
1569 st->cipherblk = ssh->sccipher->blksize;
1572 if (st->cipherblk < 8)
1574 st->maclen = ssh->scmac ? ssh->scmac->len : 0;
1576 if (ssh->sccipher && (ssh->sccipher->flags & SSH_CIPHER_IS_CBC) &&
1577 ssh->scmac && !ssh->scmac_etm) {
1579 * When dealing with a CBC-mode cipher, we want to avoid the
1580 * possibility of an attacker's tweaking the ciphertext stream
1581 * so as to cause us to feed the same block to the block
1582 * cipher more than once and thus leak information
1583 * (VU#958563). The way we do this is not to take any
1584 * decisions on the basis of anything we've decrypted until
1585 * we've verified it with a MAC. That includes the packet
1586 * length, so we just read data and check the MAC repeatedly,
1587 * and when the MAC passes, see if the length we've got is
1590 * This defence is unnecessary in OpenSSH ETM mode, because
1591 * the whole point of ETM mode is that the attacker can't
1592 * tweak the ciphertext stream at all without the MAC
1593 * detecting it before we decrypt anything.
1596 /* May as well allocate the whole lot now. */
1597 st->pktin->data = snewn(OUR_V2_PACKETLIMIT + st->maclen + APIEXTRA,
1600 /* Read an amount corresponding to the MAC. */
1601 for (st->i = 0; st->i < st->maclen; st->i++) {
1602 while ((*datalen) == 0)
1604 st->pktin->data[st->i] = *(*data)++;
1610 unsigned char seq[4];
1611 ssh->scmac->start(ssh->sc_mac_ctx);
1612 PUT_32BIT(seq, st->incoming_sequence);
1613 ssh->scmac->bytes(ssh->sc_mac_ctx, seq, 4);
1616 for (;;) { /* Once around this loop per cipher block. */
1617 /* Read another cipher-block's worth, and tack it onto the end. */
1618 for (st->i = 0; st->i < st->cipherblk; st->i++) {
1619 while ((*datalen) == 0)
1621 st->pktin->data[st->packetlen+st->maclen+st->i] = *(*data)++;
1624 /* Decrypt one more block (a little further back in the stream). */
1625 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
1626 st->pktin->data + st->packetlen,
1628 /* Feed that block to the MAC. */
1629 ssh->scmac->bytes(ssh->sc_mac_ctx,
1630 st->pktin->data + st->packetlen, st->cipherblk);
1631 st->packetlen += st->cipherblk;
1632 /* See if that gives us a valid packet. */
1633 if (ssh->scmac->verresult(ssh->sc_mac_ctx,
1634 st->pktin->data + st->packetlen) &&
1635 ((st->len = toint(GET_32BIT(st->pktin->data))) ==
1638 if (st->packetlen >= OUR_V2_PACKETLIMIT) {
1639 bombout(("No valid incoming packet found"));
1640 ssh_free_packet(st->pktin);
1644 st->pktin->maxlen = st->packetlen + st->maclen;
1645 st->pktin->data = sresize(st->pktin->data,
1646 st->pktin->maxlen + APIEXTRA,
1648 } else if (ssh->scmac && ssh->scmac_etm) {
1649 st->pktin->data = snewn(4 + APIEXTRA, unsigned char);
1652 * OpenSSH encrypt-then-MAC mode: the packet length is
1653 * unencrypted, unless the cipher supports length encryption.
1655 for (st->i = st->len = 0; st->i < 4; st->i++) {
1656 while ((*datalen) == 0)
1658 st->pktin->data[st->i] = *(*data)++;
1661 /* Cipher supports length decryption, so do it */
1662 if (ssh->sccipher && (ssh->sccipher->flags & SSH_CIPHER_SEPARATE_LENGTH)) {
1663 /* Keep the packet the same though, so the MAC passes */
1664 unsigned char len[4];
1665 memcpy(len, st->pktin->data, 4);
1666 ssh->sccipher->decrypt_length(ssh->sc_cipher_ctx, len, 4, st->incoming_sequence);
1667 st->len = toint(GET_32BIT(len));
1669 st->len = toint(GET_32BIT(st->pktin->data));
1673 * _Completely_ silly lengths should be stomped on before they
1674 * do us any more damage.
1676 if (st->len < 0 || st->len > OUR_V2_PACKETLIMIT ||
1677 st->len % st->cipherblk != 0) {
1678 bombout(("Incoming packet length field was garbled"));
1679 ssh_free_packet(st->pktin);
1684 * So now we can work out the total packet length.
1686 st->packetlen = st->len + 4;
1689 * Allocate memory for the rest of the packet.
1691 st->pktin->maxlen = st->packetlen + st->maclen;
1692 st->pktin->data = sresize(st->pktin->data,
1693 st->pktin->maxlen + APIEXTRA,
1697 * Read the remainder of the packet.
1699 for (st->i = 4; st->i < st->packetlen + st->maclen; st->i++) {
1700 while ((*datalen) == 0)
1702 st->pktin->data[st->i] = *(*data)++;
1710 && !ssh->scmac->verify(ssh->sc_mac_ctx, st->pktin->data,
1711 st->len + 4, st->incoming_sequence)) {
1712 bombout(("Incorrect MAC received on packet"));
1713 ssh_free_packet(st->pktin);
1717 /* Decrypt everything between the length field and the MAC. */
1719 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
1720 st->pktin->data + 4,
1723 st->pktin->data = snewn(st->cipherblk + APIEXTRA, unsigned char);
1726 * Acquire and decrypt the first block of the packet. This will
1727 * contain the length and padding details.
1729 for (st->i = st->len = 0; st->i < st->cipherblk; st->i++) {
1730 while ((*datalen) == 0)
1732 st->pktin->data[st->i] = *(*data)++;
1737 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
1738 st->pktin->data, st->cipherblk);
1741 * Now get the length figure.
1743 st->len = toint(GET_32BIT(st->pktin->data));
1746 * _Completely_ silly lengths should be stomped on before they
1747 * do us any more damage.
1749 if (st->len < 0 || st->len > OUR_V2_PACKETLIMIT ||
1750 (st->len + 4) % st->cipherblk != 0) {
1751 bombout(("Incoming packet was garbled on decryption"));
1752 ssh_free_packet(st->pktin);
1757 * So now we can work out the total packet length.
1759 st->packetlen = st->len + 4;
1762 * Allocate memory for the rest of the packet.
1764 st->pktin->maxlen = st->packetlen + st->maclen;
1765 st->pktin->data = sresize(st->pktin->data,
1766 st->pktin->maxlen + APIEXTRA,
1770 * Read and decrypt the remainder of the packet.
1772 for (st->i = st->cipherblk; st->i < st->packetlen + st->maclen;
1774 while ((*datalen) == 0)
1776 st->pktin->data[st->i] = *(*data)++;
1779 /* Decrypt everything _except_ the MAC. */
1781 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
1782 st->pktin->data + st->cipherblk,
1783 st->packetlen - st->cipherblk);
1789 && !ssh->scmac->verify(ssh->sc_mac_ctx, st->pktin->data,
1790 st->len + 4, st->incoming_sequence)) {
1791 bombout(("Incorrect MAC received on packet"));
1792 ssh_free_packet(st->pktin);
1796 /* Get and sanity-check the amount of random padding. */
1797 st->pad = st->pktin->data[4];
1798 if (st->pad < 4 || st->len - st->pad < 1) {
1799 bombout(("Invalid padding length on received packet"));
1800 ssh_free_packet(st->pktin);
1804 * This enables us to deduce the payload length.
1806 st->payload = st->len - st->pad - 1;
1808 st->pktin->length = st->payload + 5;
1809 st->pktin->encrypted_len = st->packetlen;
1811 st->pktin->sequence = st->incoming_sequence++;
1813 st->pktin->length = st->packetlen - st->pad;
1814 assert(st->pktin->length >= 0);
1817 * Decompress packet payload.
1820 unsigned char *newpayload;
1823 ssh->sccomp->decompress(ssh->sc_comp_ctx,
1824 st->pktin->data + 5, st->pktin->length - 5,
1825 &newpayload, &newlen)) {
1826 if (st->pktin->maxlen < newlen + 5) {
1827 st->pktin->maxlen = newlen + 5;
1828 st->pktin->data = sresize(st->pktin->data,
1829 st->pktin->maxlen + APIEXTRA,
1832 st->pktin->length = 5 + newlen;
1833 memcpy(st->pktin->data + 5, newpayload, newlen);
1839 * RFC 4253 doesn't explicitly say that completely empty packets
1840 * with no type byte are forbidden, so treat them as deserving
1841 * an SSH_MSG_UNIMPLEMENTED.
1843 if (st->pktin->length <= 5) { /* == 5 we hope, but robustness */
1844 ssh2_msg_something_unimplemented(ssh, st->pktin);
1848 * pktin->body and pktin->length should identify the semantic
1849 * content of the packet, excluding the initial type byte.
1851 st->pktin->type = st->pktin->data[5];
1852 st->pktin->body = st->pktin->data + 6;
1853 st->pktin->length -= 6;
1854 assert(st->pktin->length >= 0); /* one last double-check */
1857 ssh2_log_incoming_packet(ssh, st->pktin);
1859 st->pktin->savedpos = 0;
1861 crFinish(st->pktin);
1864 static struct Packet *ssh2_bare_connection_rdpkt(Ssh ssh,
1865 const unsigned char **data,
1868 struct rdpkt2_bare_state_tag *st = &ssh->rdpkt2_bare_state;
1870 crBegin(ssh->ssh2_bare_rdpkt_crstate);
1873 * Read the packet length field.
1875 for (st->i = 0; st->i < 4; st->i++) {
1876 while ((*datalen) == 0)
1878 st->length[st->i] = *(*data)++;
1882 st->packetlen = toint(GET_32BIT_MSB_FIRST(st->length));
1883 if (st->packetlen <= 0 || st->packetlen >= OUR_V2_PACKETLIMIT) {
1884 bombout(("Invalid packet length received"));
1888 st->pktin = ssh_new_packet();
1889 st->pktin->data = snewn(st->packetlen, unsigned char);
1891 st->pktin->encrypted_len = st->packetlen;
1893 st->pktin->sequence = st->incoming_sequence++;
1896 * Read the remainder of the packet.
1898 for (st->i = 0; st->i < st->packetlen; st->i++) {
1899 while ((*datalen) == 0)
1901 st->pktin->data[st->i] = *(*data)++;
1906 * pktin->body and pktin->length should identify the semantic
1907 * content of the packet, excluding the initial type byte.
1909 st->pktin->type = st->pktin->data[0];
1910 st->pktin->body = st->pktin->data + 1;
1911 st->pktin->length = st->packetlen - 1;
1914 * Log incoming packet, possibly omitting sensitive fields.
1917 ssh2_log_incoming_packet(ssh, st->pktin);
1919 st->pktin->savedpos = 0;
1921 crFinish(st->pktin);
1924 static int s_wrpkt_prepare(Ssh ssh, struct Packet *pkt, int *offset_p)
1926 int pad, biglen, i, pktoffs;
1930 * XXX various versions of SC (including 8.8.4) screw up the
1931 * register allocation in this function and use the same register
1932 * (D6) for len and as a temporary, with predictable results. The
1933 * following sledgehammer prevents this.
1940 ssh1_log_outgoing_packet(ssh, pkt);
1942 if (ssh->v1_compressing) {
1943 unsigned char *compblk;
1945 zlib_compress_block(ssh->cs_comp_ctx,
1946 pkt->data + 12, pkt->length - 12,
1947 &compblk, &complen);
1948 ssh_pkt_ensure(pkt, complen + 2); /* just in case it's got bigger */
1949 memcpy(pkt->data + 12, compblk, complen);
1951 pkt->length = complen + 12;
1954 ssh_pkt_ensure(pkt, pkt->length + 4); /* space for CRC */
1956 len = pkt->length - 4 - 8; /* len(type+data+CRC) */
1957 pad = 8 - (len % 8);
1959 biglen = len + pad; /* len(padding+type+data+CRC) */
1961 for (i = pktoffs; i < 4+8; i++)
1962 pkt->data[i] = random_byte();
1963 crc = crc32_compute(pkt->data + pktoffs + 4, biglen - 4); /* all ex len */
1964 PUT_32BIT(pkt->data + pktoffs + 4 + biglen - 4, crc);
1965 PUT_32BIT(pkt->data + pktoffs, len);
1968 ssh->cipher->encrypt(ssh->v1_cipher_ctx,
1969 pkt->data + pktoffs + 4, biglen);
1971 if (offset_p) *offset_p = pktoffs;
1972 return biglen + 4; /* len(length+padding+type+data+CRC) */
1975 static int s_write(Ssh ssh, void *data, int len)
1978 log_packet(ssh->logctx, PKT_OUTGOING, -1, NULL, data, len,
1979 0, NULL, NULL, 0, NULL);
1982 return sk_write(ssh->s, (char *)data, len);
1985 static void s_wrpkt(Ssh ssh, struct Packet *pkt)
1987 int len, backlog, offset;
1988 len = s_wrpkt_prepare(ssh, pkt, &offset);
1989 backlog = s_write(ssh, pkt->data + offset, len);
1990 if (backlog > SSH_MAX_BACKLOG)
1991 ssh_throttle_all(ssh, 1, backlog);
1992 ssh_free_packet(pkt);
1995 static void s_wrpkt_defer(Ssh ssh, struct Packet *pkt)
1998 len = s_wrpkt_prepare(ssh, pkt, &offset);
1999 if (ssh->deferred_len + len > ssh->deferred_size) {
2000 ssh->deferred_size = ssh->deferred_len + len + 128;
2001 ssh->deferred_send_data = sresize(ssh->deferred_send_data,
2005 memcpy(ssh->deferred_send_data + ssh->deferred_len,
2006 pkt->data + offset, len);
2007 ssh->deferred_len += len;
2008 ssh_free_packet(pkt);
2012 * Construct a SSH-1 packet with the specified contents.
2013 * (This all-at-once interface used to be the only one, but now SSH-1
2014 * packets can also be constructed incrementally.)
2016 static struct Packet *construct_packet(Ssh ssh, int pkttype, va_list ap)
2022 pkt = ssh1_pkt_init(pkttype);
2024 while ((argtype = va_arg(ap, int)) != PKT_END) {
2025 unsigned char *argp, argchar;
2027 unsigned long argint;
2030 /* Actual fields in the packet */
2032 argint = va_arg(ap, int);
2033 ssh_pkt_adduint32(pkt, argint);
2036 argchar = (unsigned char) va_arg(ap, int);
2037 ssh_pkt_addbyte(pkt, argchar);
2040 argp = va_arg(ap, unsigned char *);
2041 arglen = va_arg(ap, int);
2042 ssh_pkt_adddata(pkt, argp, arglen);
2045 sargp = va_arg(ap, char *);
2046 ssh_pkt_addstring(pkt, sargp);
2049 bn = va_arg(ap, Bignum);
2050 ssh1_pkt_addmp(pkt, bn);
2058 static void send_packet(Ssh ssh, int pkttype, ...)
2062 va_start(ap, pkttype);
2063 pkt = construct_packet(ssh, pkttype, ap);
2068 static void defer_packet(Ssh ssh, int pkttype, ...)
2072 va_start(ap, pkttype);
2073 pkt = construct_packet(ssh, pkttype, ap);
2075 s_wrpkt_defer(ssh, pkt);
2078 static int ssh_versioncmp(const char *a, const char *b)
2081 unsigned long av, bv;
2083 av = strtoul(a, &ae, 10);
2084 bv = strtoul(b, &be, 10);
2086 return (av < bv ? -1 : +1);
2091 av = strtoul(ae, &ae, 10);
2092 bv = strtoul(be, &be, 10);
2094 return (av < bv ? -1 : +1);
2099 * Utility routines for putting an SSH-protocol `string' and
2100 * `uint32' into a hash state.
2102 static void hash_string(const struct ssh_hash *h, void *s, void *str, int len)
2104 unsigned char lenblk[4];
2105 PUT_32BIT(lenblk, len);
2106 h->bytes(s, lenblk, 4);
2107 h->bytes(s, str, len);
2110 static void hash_uint32(const struct ssh_hash *h, void *s, unsigned i)
2112 unsigned char intblk[4];
2113 PUT_32BIT(intblk, i);
2114 h->bytes(s, intblk, 4);
2118 * Packet construction functions. Mostly shared between SSH-1 and SSH-2.
2120 static void ssh_pkt_ensure(struct Packet *pkt, int length)
2122 if (pkt->maxlen < length) {
2123 unsigned char *body = pkt->body;
2124 int offset = body ? body - pkt->data : 0;
2125 pkt->maxlen = length + 256;
2126 pkt->data = sresize(pkt->data, pkt->maxlen + APIEXTRA, unsigned char);
2127 if (body) pkt->body = pkt->data + offset;
2130 static void ssh_pkt_adddata(struct Packet *pkt, const void *data, int len)
2133 ssh_pkt_ensure(pkt, pkt->length);
2134 memcpy(pkt->data + pkt->length - len, data, len);
2136 static void ssh_pkt_addbyte(struct Packet *pkt, unsigned char byte)
2138 ssh_pkt_adddata(pkt, &byte, 1);
2140 static void ssh2_pkt_addbool(struct Packet *pkt, unsigned char value)
2142 ssh_pkt_adddata(pkt, &value, 1);
2144 static void ssh_pkt_adduint32(struct Packet *pkt, unsigned long value)
2147 PUT_32BIT(x, value);
2148 ssh_pkt_adddata(pkt, x, 4);
2150 static void ssh_pkt_addstring_start(struct Packet *pkt)
2152 ssh_pkt_adduint32(pkt, 0);
2153 pkt->savedpos = pkt->length;
2155 static void ssh_pkt_addstring_data(struct Packet *pkt, const char *data,
2158 ssh_pkt_adddata(pkt, data, len);
2159 PUT_32BIT(pkt->data + pkt->savedpos - 4, pkt->length - pkt->savedpos);
2161 static void ssh_pkt_addstring_str(struct Packet *pkt, const char *data)
2163 ssh_pkt_addstring_data(pkt, data, strlen(data));
2165 static void ssh_pkt_addstring(struct Packet *pkt, const char *data)
2167 ssh_pkt_addstring_start(pkt);
2168 ssh_pkt_addstring_str(pkt, data);
2170 static void ssh1_pkt_addmp(struct Packet *pkt, Bignum b)
2172 int len = ssh1_bignum_length(b);
2173 unsigned char *data = snewn(len, unsigned char);
2174 (void) ssh1_write_bignum(data, b);
2175 ssh_pkt_adddata(pkt, data, len);
2178 static unsigned char *ssh2_mpint_fmt(Bignum b, int *len)
2181 int i, n = (bignum_bitcount(b) + 7) / 8;
2182 p = snewn(n + 1, unsigned char);
2184 for (i = 1; i <= n; i++)
2185 p[i] = bignum_byte(b, n - i);
2187 while (i <= n && p[i] == 0 && (p[i + 1] & 0x80) == 0)
2189 memmove(p, p + i, n + 1 - i);
2193 static void ssh2_pkt_addmp(struct Packet *pkt, Bignum b)
2197 p = ssh2_mpint_fmt(b, &len);
2198 ssh_pkt_addstring_start(pkt);
2199 ssh_pkt_addstring_data(pkt, (char *)p, len);
2203 static struct Packet *ssh1_pkt_init(int pkt_type)
2205 struct Packet *pkt = ssh_new_packet();
2206 pkt->length = 4 + 8; /* space for length + max padding */
2207 ssh_pkt_addbyte(pkt, pkt_type);
2208 pkt->body = pkt->data + pkt->length;
2209 pkt->type = pkt_type;
2210 pkt->downstream_id = 0;
2211 pkt->additional_log_text = NULL;
2215 /* For legacy code (SSH-1 and -2 packet construction used to be separate) */
2216 #define ssh2_pkt_ensure(pkt, length) ssh_pkt_ensure(pkt, length)
2217 #define ssh2_pkt_adddata(pkt, data, len) ssh_pkt_adddata(pkt, data, len)
2218 #define ssh2_pkt_addbyte(pkt, byte) ssh_pkt_addbyte(pkt, byte)
2219 #define ssh2_pkt_adduint32(pkt, value) ssh_pkt_adduint32(pkt, value)
2220 #define ssh2_pkt_addstring_start(pkt) ssh_pkt_addstring_start(pkt)
2221 #define ssh2_pkt_addstring_str(pkt, data) ssh_pkt_addstring_str(pkt, data)
2222 #define ssh2_pkt_addstring_data(pkt, data, len) ssh_pkt_addstring_data(pkt, data, len)
2223 #define ssh2_pkt_addstring(pkt, data) ssh_pkt_addstring(pkt, data)
2225 static struct Packet *ssh2_pkt_init(int pkt_type)
2227 struct Packet *pkt = ssh_new_packet();
2228 pkt->length = 5; /* space for packet length + padding length */
2230 pkt->type = pkt_type;
2231 ssh_pkt_addbyte(pkt, (unsigned char) pkt_type);
2232 pkt->body = pkt->data + pkt->length; /* after packet type */
2233 pkt->downstream_id = 0;
2234 pkt->additional_log_text = NULL;
2239 * Construct an SSH-2 final-form packet: compress it, encrypt it,
2240 * put the MAC on it. Final packet, ready to be sent, is stored in
2241 * pkt->data. Total length is returned.
2243 static int ssh2_pkt_construct(Ssh ssh, struct Packet *pkt)
2245 int cipherblk, maclen, padding, unencrypted_prefix, i;
2248 ssh2_log_outgoing_packet(ssh, pkt);
2250 if (ssh->bare_connection) {
2252 * Trivial packet construction for the bare connection
2255 PUT_32BIT(pkt->data + 1, pkt->length - 5);
2256 pkt->body = pkt->data + 1;
2257 ssh->v2_outgoing_sequence++; /* only for diagnostics, really */
2258 return pkt->length - 1;
2262 * Compress packet payload.
2265 unsigned char *newpayload;
2268 ssh->cscomp->compress(ssh->cs_comp_ctx, pkt->data + 5,
2270 &newpayload, &newlen)) {
2272 ssh2_pkt_adddata(pkt, newpayload, newlen);
2278 * Add padding. At least four bytes, and must also bring total
2279 * length (minus MAC) up to a multiple of the block size.
2280 * If pkt->forcepad is set, make sure the packet is at least that size
2283 cipherblk = ssh->cscipher ? ssh->cscipher->blksize : 8; /* block size */
2284 cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */
2286 unencrypted_prefix = (ssh->csmac && ssh->csmac_etm) ? 4 : 0;
2287 if (pkt->length + padding < pkt->forcepad)
2288 padding = pkt->forcepad - pkt->length;
2290 (cipherblk - (pkt->length - unencrypted_prefix + padding) % cipherblk)
2292 assert(padding <= 255);
2293 maclen = ssh->csmac ? ssh->csmac->len : 0;
2294 ssh2_pkt_ensure(pkt, pkt->length + padding + maclen);
2295 pkt->data[4] = padding;
2296 for (i = 0; i < padding; i++)
2297 pkt->data[pkt->length + i] = random_byte();
2298 PUT_32BIT(pkt->data, pkt->length + padding - 4);
2300 /* Encrypt length if the scheme requires it */
2301 if (ssh->cscipher && (ssh->cscipher->flags & SSH_CIPHER_SEPARATE_LENGTH)) {
2302 ssh->cscipher->encrypt_length(ssh->cs_cipher_ctx, pkt->data, 4,
2303 ssh->v2_outgoing_sequence);
2306 if (ssh->csmac && ssh->csmac_etm) {
2308 * OpenSSH-defined encrypt-then-MAC protocol.
2311 ssh->cscipher->encrypt(ssh->cs_cipher_ctx,
2312 pkt->data + 4, pkt->length + padding - 4);
2313 ssh->csmac->generate(ssh->cs_mac_ctx, pkt->data,
2314 pkt->length + padding,
2315 ssh->v2_outgoing_sequence);
2318 * SSH-2 standard protocol.
2321 ssh->csmac->generate(ssh->cs_mac_ctx, pkt->data,
2322 pkt->length + padding,
2323 ssh->v2_outgoing_sequence);
2325 ssh->cscipher->encrypt(ssh->cs_cipher_ctx,
2326 pkt->data, pkt->length + padding);
2329 ssh->v2_outgoing_sequence++; /* whether or not we MACed */
2330 pkt->encrypted_len = pkt->length + padding;
2332 /* Ready-to-send packet starts at pkt->data. We return length. */
2333 pkt->body = pkt->data;
2334 return pkt->length + padding + maclen;
2338 * Routines called from the main SSH code to send packets. There
2339 * are quite a few of these, because we have two separate
2340 * mechanisms for delaying the sending of packets:
2342 * - In order to send an IGNORE message and a password message in
2343 * a single fixed-length blob, we require the ability to
2344 * concatenate the encrypted forms of those two packets _into_ a
2345 * single blob and then pass it to our <network.h> transport
2346 * layer in one go. Hence, there's a deferment mechanism which
2347 * works after packet encryption.
2349 * - In order to avoid sending any connection-layer messages
2350 * during repeat key exchange, we have to queue up any such
2351 * outgoing messages _before_ they are encrypted (and in
2352 * particular before they're allocated sequence numbers), and
2353 * then send them once we've finished.
2355 * I call these mechanisms `defer' and `queue' respectively, so as
2356 * to distinguish them reasonably easily.
2358 * The functions send_noqueue() and defer_noqueue() free the packet
2359 * structure they are passed. Every outgoing packet goes through
2360 * precisely one of these functions in its life; packets passed to
2361 * ssh2_pkt_send() or ssh2_pkt_defer() either go straight to one of
2362 * these or get queued, and then when the queue is later emptied
2363 * the packets are all passed to defer_noqueue().
2365 * When using a CBC-mode cipher, it's necessary to ensure that an
2366 * attacker can't provide data to be encrypted using an IV that they
2367 * know. We ensure this by prefixing each packet that might contain
2368 * user data with an SSH_MSG_IGNORE. This is done using the deferral
2369 * mechanism, so in this case send_noqueue() ends up redirecting to
2370 * defer_noqueue(). If you don't like this inefficiency, don't use
2374 static void ssh2_pkt_defer_noqueue(Ssh, struct Packet *, int);
2375 static void ssh_pkt_defersend(Ssh);
2378 * Send an SSH-2 packet immediately, without queuing or deferring.
2380 static void ssh2_pkt_send_noqueue(Ssh ssh, struct Packet *pkt)
2384 if (ssh->cscipher != NULL && (ssh->cscipher->flags & SSH_CIPHER_IS_CBC)) {
2385 /* We need to send two packets, so use the deferral mechanism. */
2386 ssh2_pkt_defer_noqueue(ssh, pkt, FALSE);
2387 ssh_pkt_defersend(ssh);
2390 len = ssh2_pkt_construct(ssh, pkt);
2391 backlog = s_write(ssh, pkt->body, len);
2392 if (backlog > SSH_MAX_BACKLOG)
2393 ssh_throttle_all(ssh, 1, backlog);
2395 ssh->outgoing_data_size += pkt->encrypted_len;
2396 if (!ssh->kex_in_progress &&
2397 !ssh->bare_connection &&
2398 ssh->max_data_size != 0 &&
2399 ssh->outgoing_data_size > ssh->max_data_size)
2400 do_ssh2_transport(ssh, "too much data sent", -1, NULL);
2402 ssh_free_packet(pkt);
2406 * Defer an SSH-2 packet.
2408 static void ssh2_pkt_defer_noqueue(Ssh ssh, struct Packet *pkt, int noignore)
2411 if (ssh->cscipher != NULL && (ssh->cscipher->flags & SSH_CIPHER_IS_CBC) &&
2412 ssh->deferred_len == 0 && !noignore &&
2413 !(ssh->remote_bugs & BUG_CHOKES_ON_SSH2_IGNORE)) {
2415 * Interpose an SSH_MSG_IGNORE to ensure that user data don't
2416 * get encrypted with a known IV.
2418 struct Packet *ipkt = ssh2_pkt_init(SSH2_MSG_IGNORE);
2419 ssh2_pkt_addstring_start(ipkt);
2420 ssh2_pkt_defer_noqueue(ssh, ipkt, TRUE);
2422 len = ssh2_pkt_construct(ssh, pkt);
2423 if (ssh->deferred_len + len > ssh->deferred_size) {
2424 ssh->deferred_size = ssh->deferred_len + len + 128;
2425 ssh->deferred_send_data = sresize(ssh->deferred_send_data,
2429 memcpy(ssh->deferred_send_data + ssh->deferred_len, pkt->body, len);
2430 ssh->deferred_len += len;
2431 ssh->deferred_data_size += pkt->encrypted_len;
2432 ssh_free_packet(pkt);
2436 * Queue an SSH-2 packet.
2438 static void ssh2_pkt_queue(Ssh ssh, struct Packet *pkt)
2440 assert(ssh->queueing);
2442 if (ssh->queuelen >= ssh->queuesize) {
2443 ssh->queuesize = ssh->queuelen + 32;
2444 ssh->queue = sresize(ssh->queue, ssh->queuesize, struct Packet *);
2447 ssh->queue[ssh->queuelen++] = pkt;
2451 * Either queue or send a packet, depending on whether queueing is
2454 static void ssh2_pkt_send(Ssh ssh, struct Packet *pkt)
2457 ssh2_pkt_queue(ssh, pkt);
2459 ssh2_pkt_send_noqueue(ssh, pkt);
2463 * Either queue or defer a packet, depending on whether queueing is
2466 static void ssh2_pkt_defer(Ssh ssh, struct Packet *pkt)
2469 ssh2_pkt_queue(ssh, pkt);
2471 ssh2_pkt_defer_noqueue(ssh, pkt, FALSE);
2475 * Send the whole deferred data block constructed by
2476 * ssh2_pkt_defer() or SSH-1's defer_packet().
2478 * The expected use of the defer mechanism is that you call
2479 * ssh2_pkt_defer() a few times, then call ssh_pkt_defersend(). If
2480 * not currently queueing, this simply sets up deferred_send_data
2481 * and then sends it. If we _are_ currently queueing, the calls to
2482 * ssh2_pkt_defer() put the deferred packets on to the queue
2483 * instead, and therefore ssh_pkt_defersend() has no deferred data
2484 * to send. Hence, there's no need to make it conditional on
2487 static void ssh_pkt_defersend(Ssh ssh)
2490 backlog = s_write(ssh, ssh->deferred_send_data, ssh->deferred_len);
2491 ssh->deferred_len = ssh->deferred_size = 0;
2492 sfree(ssh->deferred_send_data);
2493 ssh->deferred_send_data = NULL;
2494 if (backlog > SSH_MAX_BACKLOG)
2495 ssh_throttle_all(ssh, 1, backlog);
2497 ssh->outgoing_data_size += ssh->deferred_data_size;
2498 if (!ssh->kex_in_progress &&
2499 !ssh->bare_connection &&
2500 ssh->max_data_size != 0 &&
2501 ssh->outgoing_data_size > ssh->max_data_size)
2502 do_ssh2_transport(ssh, "too much data sent", -1, NULL);
2503 ssh->deferred_data_size = 0;
2507 * Send a packet whose length needs to be disguised (typically
2508 * passwords or keyboard-interactive responses).
2510 static void ssh2_pkt_send_with_padding(Ssh ssh, struct Packet *pkt,
2516 * The simplest way to do this is to adjust the
2517 * variable-length padding field in the outgoing packet.
2519 * Currently compiled out, because some Cisco SSH servers
2520 * don't like excessively padded packets (bah, why's it
2523 pkt->forcepad = padsize;
2524 ssh2_pkt_send(ssh, pkt);
2529 * If we can't do that, however, an alternative approach is
2530 * to use the pkt_defer mechanism to bundle the packet
2531 * tightly together with an SSH_MSG_IGNORE such that their
2532 * combined length is a constant. So first we construct the
2533 * final form of this packet and defer its sending.
2535 ssh2_pkt_defer(ssh, pkt);
2538 * Now construct an SSH_MSG_IGNORE which includes a string
2539 * that's an exact multiple of the cipher block size. (If
2540 * the cipher is NULL so that the block size is
2541 * unavailable, we don't do this trick at all, because we
2542 * gain nothing by it.)
2544 if (ssh->cscipher &&
2545 !(ssh->remote_bugs & BUG_CHOKES_ON_SSH2_IGNORE)) {
2548 stringlen = (256 - ssh->deferred_len);
2549 stringlen += ssh->cscipher->blksize - 1;
2550 stringlen -= (stringlen % ssh->cscipher->blksize);
2553 * Temporarily disable actual compression, so we
2554 * can guarantee to get this string exactly the
2555 * length we want it. The compression-disabling
2556 * routine should return an integer indicating how
2557 * many bytes we should adjust our string length
2561 ssh->cscomp->disable_compression(ssh->cs_comp_ctx);
2563 pkt = ssh2_pkt_init(SSH2_MSG_IGNORE);
2564 ssh2_pkt_addstring_start(pkt);
2565 for (i = 0; i < stringlen; i++) {
2566 char c = (char) random_byte();
2567 ssh2_pkt_addstring_data(pkt, &c, 1);
2569 ssh2_pkt_defer(ssh, pkt);
2571 ssh_pkt_defersend(ssh);
2576 * Send all queued SSH-2 packets. We send them by means of
2577 * ssh2_pkt_defer_noqueue(), in case they included a pair of
2578 * packets that needed to be lumped together.
2580 static void ssh2_pkt_queuesend(Ssh ssh)
2584 assert(!ssh->queueing);
2586 for (i = 0; i < ssh->queuelen; i++)
2587 ssh2_pkt_defer_noqueue(ssh, ssh->queue[i], FALSE);
2590 ssh_pkt_defersend(ssh);
2594 void bndebug(char *string, Bignum b)
2598 p = ssh2_mpint_fmt(b, &len);
2599 debug(("%s", string));
2600 for (i = 0; i < len; i++)
2601 debug((" %02x", p[i]));
2607 static void hash_mpint(const struct ssh_hash *h, void *s, Bignum b)
2611 p = ssh2_mpint_fmt(b, &len);
2612 hash_string(h, s, p, len);
2617 * Packet decode functions for both SSH-1 and SSH-2.
2619 static unsigned long ssh_pkt_getuint32(struct Packet *pkt)
2621 unsigned long value;
2622 if (pkt->length - pkt->savedpos < 4)
2623 return 0; /* arrgh, no way to decline (FIXME?) */
2624 value = GET_32BIT(pkt->body + pkt->savedpos);
2628 static int ssh2_pkt_getbool(struct Packet *pkt)
2630 unsigned long value;
2631 if (pkt->length - pkt->savedpos < 1)
2632 return 0; /* arrgh, no way to decline (FIXME?) */
2633 value = pkt->body[pkt->savedpos] != 0;
2637 static void ssh_pkt_getstring(struct Packet *pkt, char **p, int *length)
2642 if (pkt->length - pkt->savedpos < 4)
2644 len = toint(GET_32BIT(pkt->body + pkt->savedpos));
2649 if (pkt->length - pkt->savedpos < *length)
2651 *p = (char *)(pkt->body + pkt->savedpos);
2652 pkt->savedpos += *length;
2654 static void *ssh_pkt_getdata(struct Packet *pkt, int length)
2656 if (pkt->length - pkt->savedpos < length)
2658 pkt->savedpos += length;
2659 return pkt->body + (pkt->savedpos - length);
2661 static int ssh1_pkt_getrsakey(struct Packet *pkt, struct RSAKey *key,
2662 const unsigned char **keystr)
2666 j = makekey(pkt->body + pkt->savedpos,
2667 pkt->length - pkt->savedpos,
2674 assert(pkt->savedpos < pkt->length);
2678 static Bignum ssh1_pkt_getmp(struct Packet *pkt)
2683 j = ssh1_read_bignum(pkt->body + pkt->savedpos,
2684 pkt->length - pkt->savedpos, &b);
2692 static Bignum ssh2_pkt_getmp(struct Packet *pkt)
2698 ssh_pkt_getstring(pkt, &p, &length);
2703 b = bignum_from_bytes((unsigned char *)p, length);
2708 * Helper function to add an SSH-2 signature blob to a packet.
2709 * Expects to be shown the public key blob as well as the signature
2710 * blob. Normally works just like ssh2_pkt_addstring, but will
2711 * fiddle with the signature packet if necessary for
2712 * BUG_SSH2_RSA_PADDING.
2714 static void ssh2_add_sigblob(Ssh ssh, struct Packet *pkt,
2715 void *pkblob_v, int pkblob_len,
2716 void *sigblob_v, int sigblob_len)
2718 unsigned char *pkblob = (unsigned char *)pkblob_v;
2719 unsigned char *sigblob = (unsigned char *)sigblob_v;
2721 /* dmemdump(pkblob, pkblob_len); */
2722 /* dmemdump(sigblob, sigblob_len); */
2725 * See if this is in fact an ssh-rsa signature and a buggy
2726 * server; otherwise we can just do this the easy way.
2728 if ((ssh->remote_bugs & BUG_SSH2_RSA_PADDING) && pkblob_len > 4+7+4 &&
2729 (GET_32BIT(pkblob) == 7 && !memcmp(pkblob+4, "ssh-rsa", 7))) {
2730 int pos, len, siglen;
2733 * Find the byte length of the modulus.
2736 pos = 4+7; /* skip over "ssh-rsa" */
2737 len = toint(GET_32BIT(pkblob+pos)); /* get length of exponent */
2738 if (len < 0 || len > pkblob_len - pos - 4)
2740 pos += 4 + len; /* skip over exponent */
2741 if (pkblob_len - pos < 4)
2743 len = toint(GET_32BIT(pkblob+pos)); /* find length of modulus */
2744 if (len < 0 || len > pkblob_len - pos - 4)
2746 pos += 4; /* find modulus itself */
2747 while (len > 0 && pkblob[pos] == 0)
2749 /* debug(("modulus length is %d\n", len)); */
2752 * Now find the signature integer.
2754 pos = 4+7; /* skip over "ssh-rsa" */
2755 if (sigblob_len < pos+4)
2757 siglen = toint(GET_32BIT(sigblob+pos));
2758 if (siglen != sigblob_len - pos - 4)
2760 /* debug(("signature length is %d\n", siglen)); */
2762 if (len != siglen) {
2763 unsigned char newlen[4];
2764 ssh2_pkt_addstring_start(pkt);
2765 ssh2_pkt_addstring_data(pkt, (char *)sigblob, pos);
2766 /* dmemdump(sigblob, pos); */
2767 pos += 4; /* point to start of actual sig */
2768 PUT_32BIT(newlen, len);
2769 ssh2_pkt_addstring_data(pkt, (char *)newlen, 4);
2770 /* dmemdump(newlen, 4); */
2772 while (len-- > siglen) {
2773 ssh2_pkt_addstring_data(pkt, (char *)newlen, 1);
2774 /* dmemdump(newlen, 1); */
2776 ssh2_pkt_addstring_data(pkt, (char *)(sigblob+pos), siglen);
2777 /* dmemdump(sigblob+pos, siglen); */
2781 /* Otherwise fall through and do it the easy way. We also come
2782 * here as a fallback if we discover above that the key blob
2783 * is misformatted in some way. */
2787 ssh2_pkt_addstring_start(pkt);
2788 ssh2_pkt_addstring_data(pkt, (char *)sigblob, sigblob_len);
2792 * Examine the remote side's version string and compare it against
2793 * a list of known buggy implementations.
2795 static void ssh_detect_bugs(Ssh ssh, char *vstring)
2797 char *imp; /* pointer to implementation part */
2799 imp += strcspn(imp, "-");
2801 imp += strcspn(imp, "-");
2804 ssh->remote_bugs = 0;
2807 * General notes on server version strings:
2808 * - Not all servers reporting "Cisco-1.25" have all the bugs listed
2809 * here -- in particular, we've heard of one that's perfectly happy
2810 * with SSH1_MSG_IGNOREs -- but this string never seems to change,
2811 * so we can't distinguish them.
2813 if (conf_get_int(ssh->conf, CONF_sshbug_ignore1) == FORCE_ON ||
2814 (conf_get_int(ssh->conf, CONF_sshbug_ignore1) == AUTO &&
2815 (!strcmp(imp, "1.2.18") || !strcmp(imp, "1.2.19") ||
2816 !strcmp(imp, "1.2.20") || !strcmp(imp, "1.2.21") ||
2817 !strcmp(imp, "1.2.22") || !strcmp(imp, "Cisco-1.25") ||
2818 !strcmp(imp, "OSU_1.4alpha3") || !strcmp(imp, "OSU_1.5alpha4")))) {
2820 * These versions don't support SSH1_MSG_IGNORE, so we have
2821 * to use a different defence against password length
2824 ssh->remote_bugs |= BUG_CHOKES_ON_SSH1_IGNORE;
2825 logevent("We believe remote version has SSH-1 ignore bug");
2828 if (conf_get_int(ssh->conf, CONF_sshbug_plainpw1) == FORCE_ON ||
2829 (conf_get_int(ssh->conf, CONF_sshbug_plainpw1) == AUTO &&
2830 (!strcmp(imp, "Cisco-1.25") || !strcmp(imp, "OSU_1.4alpha3")))) {
2832 * These versions need a plain password sent; they can't
2833 * handle having a null and a random length of data after
2836 ssh->remote_bugs |= BUG_NEEDS_SSH1_PLAIN_PASSWORD;
2837 logevent("We believe remote version needs a plain SSH-1 password");
2840 if (conf_get_int(ssh->conf, CONF_sshbug_rsa1) == FORCE_ON ||
2841 (conf_get_int(ssh->conf, CONF_sshbug_rsa1) == AUTO &&
2842 (!strcmp(imp, "Cisco-1.25")))) {
2844 * These versions apparently have no clue whatever about
2845 * RSA authentication and will panic and die if they see
2846 * an AUTH_RSA message.
2848 ssh->remote_bugs |= BUG_CHOKES_ON_RSA;
2849 logevent("We believe remote version can't handle SSH-1 RSA authentication");
2852 if (conf_get_int(ssh->conf, CONF_sshbug_hmac2) == FORCE_ON ||
2853 (conf_get_int(ssh->conf, CONF_sshbug_hmac2) == AUTO &&
2854 !wc_match("* VShell", imp) &&
2855 (wc_match("2.1.0*", imp) || wc_match("2.0.*", imp) ||
2856 wc_match("2.2.0*", imp) || wc_match("2.3.0*", imp) ||
2857 wc_match("2.1 *", imp)))) {
2859 * These versions have the HMAC bug.
2861 ssh->remote_bugs |= BUG_SSH2_HMAC;
2862 logevent("We believe remote version has SSH-2 HMAC bug");
2865 if (conf_get_int(ssh->conf, CONF_sshbug_derivekey2) == FORCE_ON ||
2866 (conf_get_int(ssh->conf, CONF_sshbug_derivekey2) == AUTO &&
2867 !wc_match("* VShell", imp) &&
2868 (wc_match("2.0.0*", imp) || wc_match("2.0.10*", imp) ))) {
2870 * These versions have the key-derivation bug (failing to
2871 * include the literal shared secret in the hashes that
2872 * generate the keys).
2874 ssh->remote_bugs |= BUG_SSH2_DERIVEKEY;
2875 logevent("We believe remote version has SSH-2 key-derivation bug");
2878 if (conf_get_int(ssh->conf, CONF_sshbug_rsapad2) == FORCE_ON ||
2879 (conf_get_int(ssh->conf, CONF_sshbug_rsapad2) == AUTO &&
2880 (wc_match("OpenSSH_2.[5-9]*", imp) ||
2881 wc_match("OpenSSH_3.[0-2]*", imp) ||
2882 wc_match("mod_sftp/0.[0-8]*", imp) ||
2883 wc_match("mod_sftp/0.9.[0-8]", imp)))) {
2885 * These versions have the SSH-2 RSA padding bug.
2887 ssh->remote_bugs |= BUG_SSH2_RSA_PADDING;
2888 logevent("We believe remote version has SSH-2 RSA padding bug");
2891 if (conf_get_int(ssh->conf, CONF_sshbug_pksessid2) == FORCE_ON ||
2892 (conf_get_int(ssh->conf, CONF_sshbug_pksessid2) == AUTO &&
2893 wc_match("OpenSSH_2.[0-2]*", imp))) {
2895 * These versions have the SSH-2 session-ID bug in
2896 * public-key authentication.
2898 ssh->remote_bugs |= BUG_SSH2_PK_SESSIONID;
2899 logevent("We believe remote version has SSH-2 public-key-session-ID bug");
2902 if (conf_get_int(ssh->conf, CONF_sshbug_rekey2) == FORCE_ON ||
2903 (conf_get_int(ssh->conf, CONF_sshbug_rekey2) == AUTO &&
2904 (wc_match("DigiSSH_2.0", imp) ||
2905 wc_match("OpenSSH_2.[0-4]*", imp) ||
2906 wc_match("OpenSSH_2.5.[0-3]*", imp) ||
2907 wc_match("Sun_SSH_1.0", imp) ||
2908 wc_match("Sun_SSH_1.0.1", imp) ||
2909 /* All versions <= 1.2.6 (they changed their format in 1.2.7) */
2910 wc_match("WeOnlyDo-*", imp)))) {
2912 * These versions have the SSH-2 rekey bug.
2914 ssh->remote_bugs |= BUG_SSH2_REKEY;
2915 logevent("We believe remote version has SSH-2 rekey bug");
2918 if (conf_get_int(ssh->conf, CONF_sshbug_maxpkt2) == FORCE_ON ||
2919 (conf_get_int(ssh->conf, CONF_sshbug_maxpkt2) == AUTO &&
2920 (wc_match("1.36_sshlib GlobalSCAPE", imp) ||
2921 wc_match("1.36 sshlib: GlobalScape", imp)))) {
2923 * This version ignores our makpkt and needs to be throttled.
2925 ssh->remote_bugs |= BUG_SSH2_MAXPKT;
2926 logevent("We believe remote version ignores SSH-2 maximum packet size");
2929 if (conf_get_int(ssh->conf, CONF_sshbug_ignore2) == FORCE_ON) {
2931 * Servers that don't support SSH2_MSG_IGNORE. Currently,
2932 * none detected automatically.
2934 ssh->remote_bugs |= BUG_CHOKES_ON_SSH2_IGNORE;
2935 logevent("We believe remote version has SSH-2 ignore bug");
2938 if (conf_get_int(ssh->conf, CONF_sshbug_oldgex2) == FORCE_ON ||
2939 (conf_get_int(ssh->conf, CONF_sshbug_oldgex2) == AUTO &&
2940 (wc_match("OpenSSH_2.[235]*", imp)))) {
2942 * These versions only support the original (pre-RFC4419)
2943 * SSH-2 GEX request, and disconnect with a protocol error if
2944 * we use the newer version.
2946 ssh->remote_bugs |= BUG_SSH2_OLDGEX;
2947 logevent("We believe remote version has outdated SSH-2 GEX");
2950 if (conf_get_int(ssh->conf, CONF_sshbug_winadj) == FORCE_ON) {
2952 * Servers that don't support our winadj request for one
2953 * reason or another. Currently, none detected automatically.
2955 ssh->remote_bugs |= BUG_CHOKES_ON_WINADJ;
2956 logevent("We believe remote version has winadj bug");
2959 if (conf_get_int(ssh->conf, CONF_sshbug_chanreq) == FORCE_ON ||
2960 (conf_get_int(ssh->conf, CONF_sshbug_chanreq) == AUTO &&
2961 (wc_match("OpenSSH_[2-5].*", imp) ||
2962 wc_match("OpenSSH_6.[0-6]*", imp) ||
2963 wc_match("dropbear_0.[2-4][0-9]*", imp) ||
2964 wc_match("dropbear_0.5[01]*", imp)))) {
2966 * These versions have the SSH-2 channel request bug.
2967 * OpenSSH 6.7 and above do not:
2968 * https://bugzilla.mindrot.org/show_bug.cgi?id=1818
2969 * dropbear_0.52 and above do not:
2970 * https://secure.ucc.asn.au/hg/dropbear/rev/cd02449b709c
2972 ssh->remote_bugs |= BUG_SENDS_LATE_REQUEST_REPLY;
2973 logevent("We believe remote version has SSH-2 channel request bug");
2978 * The `software version' part of an SSH version string is required
2979 * to contain no spaces or minus signs.
2981 static void ssh_fix_verstring(char *str)
2983 /* Eat "<protoversion>-". */
2984 while (*str && *str != '-') str++;
2985 assert(*str == '-'); str++;
2987 /* Convert minus signs and spaces in the remaining string into
2990 if (*str == '-' || *str == ' ')
2997 * Send an appropriate SSH version string.
2999 static void ssh_send_verstring(Ssh ssh, const char *protoname, char *svers)
3003 if (ssh->version == 2) {
3005 * Construct a v2 version string.
3007 verstring = dupprintf("%s2.0-%s\015\012", protoname, sshver);
3010 * Construct a v1 version string.
3012 assert(!strcmp(protoname, "SSH-")); /* no v1 bare connection protocol */
3013 verstring = dupprintf("SSH-%s-%s\012",
3014 (ssh_versioncmp(svers, "1.5") <= 0 ?
3019 ssh_fix_verstring(verstring + strlen(protoname));
3021 /* FUZZING make PuTTY insecure, so make live use difficult. */
3025 if (ssh->version == 2) {
3028 * Record our version string.
3030 len = strcspn(verstring, "\015\012");
3031 ssh->v_c = snewn(len + 1, char);
3032 memcpy(ssh->v_c, verstring, len);
3036 logeventf(ssh, "We claim version: %.*s",
3037 strcspn(verstring, "\015\012"), verstring);
3038 s_write(ssh, verstring, strlen(verstring));
3042 static int do_ssh_init(Ssh ssh, unsigned char c)
3044 static const char protoname[] = "SSH-";
3046 struct do_ssh_init_state {
3055 crState(do_ssh_init_state);
3059 /* Search for a line beginning with the protocol name prefix in
3062 for (s->i = 0; protoname[s->i]; s->i++) {
3063 if ((char)c != protoname[s->i]) goto no;
3073 s->vstrsize = sizeof(protoname) + 16;
3074 s->vstring = snewn(s->vstrsize, char);
3075 strcpy(s->vstring, protoname);
3076 s->vslen = strlen(protoname);
3079 if (s->vslen >= s->vstrsize - 1) {
3081 s->vstring = sresize(s->vstring, s->vstrsize, char);
3083 s->vstring[s->vslen++] = c;
3086 s->version[s->i] = '\0';
3088 } else if (s->i < sizeof(s->version) - 1)
3089 s->version[s->i++] = c;
3090 } else if (c == '\012')
3092 crReturn(1); /* get another char */
3095 ssh->agentfwd_enabled = FALSE;
3096 ssh->rdpkt2_state.incoming_sequence = 0;
3098 s->vstring[s->vslen] = 0;
3099 s->vstring[strcspn(s->vstring, "\015\012")] = '\0';/* remove EOL chars */
3100 logeventf(ssh, "Server version: %s", s->vstring);
3101 ssh_detect_bugs(ssh, s->vstring);
3104 * Decide which SSH protocol version to support.
3107 /* Anything strictly below "2.0" means protocol 1 is supported. */
3108 s->proto1 = ssh_versioncmp(s->version, "2.0") < 0;
3109 /* Anything greater or equal to "1.99" means protocol 2 is supported. */
3110 s->proto2 = ssh_versioncmp(s->version, "1.99") >= 0;
3112 if (conf_get_int(ssh->conf, CONF_sshprot) == 0 && !s->proto1) {
3113 bombout(("SSH protocol version 1 required by configuration but "
3114 "not provided by server"));
3117 if (conf_get_int(ssh->conf, CONF_sshprot) == 3 && !s->proto2) {
3118 bombout(("SSH protocol version 2 required by configuration but "
3119 "not provided by server"));
3123 if (s->proto2 && (conf_get_int(ssh->conf, CONF_sshprot) >= 2 || !s->proto1))
3128 logeventf(ssh, "Using SSH protocol version %d", ssh->version);
3130 /* Send the version string, if we haven't already */
3131 if (conf_get_int(ssh->conf, CONF_sshprot) != 3)
3132 ssh_send_verstring(ssh, protoname, s->version);
3134 if (ssh->version == 2) {
3137 * Record their version string.
3139 len = strcspn(s->vstring, "\015\012");
3140 ssh->v_s = snewn(len + 1, char);
3141 memcpy(ssh->v_s, s->vstring, len);
3145 * Initialise SSH-2 protocol.
3147 ssh->protocol = ssh2_protocol;
3148 ssh2_protocol_setup(ssh);
3149 ssh->s_rdpkt = ssh2_rdpkt;
3152 * Initialise SSH-1 protocol.
3154 ssh->protocol = ssh1_protocol;
3155 ssh1_protocol_setup(ssh);
3156 ssh->s_rdpkt = ssh1_rdpkt;
3158 if (ssh->version == 2)
3159 do_ssh2_transport(ssh, NULL, -1, NULL);
3161 update_specials_menu(ssh->frontend);
3162 ssh->state = SSH_STATE_BEFORE_SIZE;
3163 ssh->pinger = pinger_new(ssh->conf, &ssh_backend, ssh);
3170 static int do_ssh_connection_init(Ssh ssh, unsigned char c)
3173 * Ordinary SSH begins with the banner "SSH-x.y-...". This is just
3174 * the ssh-connection part, extracted and given a trivial binary
3175 * packet protocol, so we replace 'SSH-' at the start with a new
3176 * name. In proper SSH style (though of course this part of the
3177 * proper SSH protocol _isn't_ subject to this kind of
3178 * DNS-domain-based extension), we define the new name in our
3181 static const char protoname[] =
3182 "SSHCONNECTION@putty.projects.tartarus.org-";
3184 struct do_ssh_connection_init_state {
3192 crState(do_ssh_connection_init_state);
3196 /* Search for a line beginning with the protocol name prefix in
3199 for (s->i = 0; protoname[s->i]; s->i++) {
3200 if ((char)c != protoname[s->i]) goto no;
3210 s->vstrsize = sizeof(protoname) + 16;
3211 s->vstring = snewn(s->vstrsize, char);
3212 strcpy(s->vstring, protoname);
3213 s->vslen = strlen(protoname);
3216 if (s->vslen >= s->vstrsize - 1) {
3218 s->vstring = sresize(s->vstring, s->vstrsize, char);
3220 s->vstring[s->vslen++] = c;
3223 s->version[s->i] = '\0';
3225 } else if (s->i < sizeof(s->version) - 1)
3226 s->version[s->i++] = c;
3227 } else if (c == '\012')
3229 crReturn(1); /* get another char */
3232 ssh->agentfwd_enabled = FALSE;
3233 ssh->rdpkt2_bare_state.incoming_sequence = 0;
3235 s->vstring[s->vslen] = 0;
3236 s->vstring[strcspn(s->vstring, "\015\012")] = '\0';/* remove EOL chars */
3237 logeventf(ssh, "Server version: %s", s->vstring);
3238 ssh_detect_bugs(ssh, s->vstring);
3241 * Decide which SSH protocol version to support. This is easy in
3242 * bare ssh-connection mode: only 2.0 is legal.
3244 if (ssh_versioncmp(s->version, "2.0") < 0) {
3245 bombout(("Server announces compatibility with SSH-1 in bare ssh-connection protocol"));
3248 if (conf_get_int(ssh->conf, CONF_sshprot) == 0) {
3249 bombout(("Bare ssh-connection protocol cannot be run in SSH-1-only mode"));
3255 logeventf(ssh, "Using bare ssh-connection protocol");
3257 /* Send the version string, if we haven't already */
3258 ssh_send_verstring(ssh, protoname, s->version);
3261 * Initialise bare connection protocol.
3263 ssh->protocol = ssh2_bare_connection_protocol;
3264 ssh2_bare_connection_protocol_setup(ssh);
3265 ssh->s_rdpkt = ssh2_bare_connection_rdpkt;
3267 update_specials_menu(ssh->frontend);
3268 ssh->state = SSH_STATE_BEFORE_SIZE;
3269 ssh->pinger = pinger_new(ssh->conf, &ssh_backend, ssh);
3272 * Get authconn (really just conn) under way.
3274 do_ssh2_authconn(ssh, NULL, 0, NULL);
3281 static void ssh_process_incoming_data(Ssh ssh,
3282 const unsigned char **data, int *datalen)
3284 struct Packet *pktin;
3286 pktin = ssh->s_rdpkt(ssh, data, datalen);
3288 ssh->protocol(ssh, NULL, 0, pktin);
3289 ssh_free_packet(pktin);
3293 static void ssh_queue_incoming_data(Ssh ssh,
3294 const unsigned char **data, int *datalen)
3296 bufchain_add(&ssh->queued_incoming_data, *data, *datalen);
3301 static void ssh_process_queued_incoming_data(Ssh ssh)
3304 const unsigned char *data;
3307 while (!ssh->frozen && bufchain_size(&ssh->queued_incoming_data)) {
3308 bufchain_prefix(&ssh->queued_incoming_data, &vdata, &len);
3312 while (!ssh->frozen && len > 0)
3313 ssh_process_incoming_data(ssh, &data, &len);
3316 bufchain_consume(&ssh->queued_incoming_data, origlen - len);
3320 static void ssh_set_frozen(Ssh ssh, int frozen)
3323 sk_set_frozen(ssh->s, frozen);
3324 ssh->frozen = frozen;
3327 static void ssh_gotdata(Ssh ssh, const unsigned char *data, int datalen)
3329 /* Log raw data, if we're in that mode. */
3331 log_packet(ssh->logctx, PKT_INCOMING, -1, NULL, data, datalen,
3332 0, NULL, NULL, 0, NULL);
3334 crBegin(ssh->ssh_gotdata_crstate);
3337 * To begin with, feed the characters one by one to the
3338 * protocol initialisation / selection function do_ssh_init().
3339 * When that returns 0, we're done with the initial greeting
3340 * exchange and can move on to packet discipline.
3343 int ret; /* need not be kept across crReturn */
3345 crReturnV; /* more data please */
3346 ret = ssh->do_ssh_init(ssh, *data);
3354 * We emerge from that loop when the initial negotiation is
3355 * over and we have selected an s_rdpkt function. Now pass
3356 * everything to s_rdpkt, and then pass the resulting packets
3357 * to the proper protocol handler.
3361 while (bufchain_size(&ssh->queued_incoming_data) > 0 || datalen > 0) {
3363 ssh_queue_incoming_data(ssh, &data, &datalen);
3364 /* This uses up all data and cannot cause anything interesting
3365 * to happen; indeed, for anything to happen at all, we must
3366 * return, so break out. */
3368 } else if (bufchain_size(&ssh->queued_incoming_data) > 0) {
3369 /* This uses up some or all data, and may freeze the
3371 ssh_process_queued_incoming_data(ssh);
3373 /* This uses up some or all data, and may freeze the
3375 ssh_process_incoming_data(ssh, &data, &datalen);
3377 /* FIXME this is probably EBW. */
3378 if (ssh->state == SSH_STATE_CLOSED)
3381 /* We're out of data. Go and get some more. */
3387 static int ssh_do_close(Ssh ssh, int notify_exit)
3390 struct ssh_channel *c;
3392 ssh->state = SSH_STATE_CLOSED;
3393 expire_timer_context(ssh);
3398 notify_remote_exit(ssh->frontend);
3403 * Now we must shut down any port- and X-forwarded channels going
3404 * through this connection.
3406 if (ssh->channels) {
3407 while (NULL != (c = index234(ssh->channels, 0))) {
3410 x11_close(c->u.x11.xconn);
3413 case CHAN_SOCKDATA_DORMANT:
3414 pfd_close(c->u.pfd.pf);
3417 del234(ssh->channels, c); /* moving next one to index 0 */
3418 if (ssh->version == 2)
3419 bufchain_clear(&c->v.v2.outbuffer);
3424 * Go through port-forwardings, and close any associated
3425 * listening sockets.
3427 if (ssh->portfwds) {
3428 struct ssh_portfwd *pf;
3429 while (NULL != (pf = index234(ssh->portfwds, 0))) {
3430 /* Dispose of any listening socket. */
3432 pfl_terminate(pf->local);
3433 del234(ssh->portfwds, pf); /* moving next one to index 0 */
3436 freetree234(ssh->portfwds);
3437 ssh->portfwds = NULL;
3441 * Also stop attempting to connection-share.
3443 if (ssh->connshare) {
3444 sharestate_free(ssh->connshare);
3445 ssh->connshare = NULL;
3451 static void ssh_socket_log(Plug plug, int type, SockAddr addr, int port,
3452 const char *error_msg, int error_code)
3454 Ssh ssh = (Ssh) plug;
3455 char addrbuf[256], *msg;
3457 if (ssh->attempting_connshare) {
3459 * While we're attempting connection sharing, don't loudly log
3460 * everything that happens. Real TCP connections need to be
3461 * logged when we _start_ trying to connect, because it might
3462 * be ages before they respond if something goes wrong; but
3463 * connection sharing is local and quick to respond, and it's
3464 * sufficient to simply wait and see whether it worked
3468 sk_getaddr(addr, addrbuf, lenof(addrbuf));
3471 if (sk_addr_needs_port(addr)) {
3472 msg = dupprintf("Connecting to %s port %d", addrbuf, port);
3474 msg = dupprintf("Connecting to %s", addrbuf);
3477 msg = dupprintf("Failed to connect to %s: %s", addrbuf, error_msg);
3485 void ssh_connshare_log(Ssh ssh, int event, const char *logtext,
3486 const char *ds_err, const char *us_err)
3488 if (event == SHARE_NONE) {
3489 /* In this case, 'logtext' is an error message indicating a
3490 * reason why connection sharing couldn't be set up _at all_.
3491 * Failing that, ds_err and us_err indicate why we couldn't be
3492 * a downstream and an upstream respectively. */
3494 logeventf(ssh, "Could not set up connection sharing: %s", logtext);
3497 logeventf(ssh, "Could not set up connection sharing"
3498 " as downstream: %s", ds_err);
3500 logeventf(ssh, "Could not set up connection sharing"
3501 " as upstream: %s", us_err);
3503 } else if (event == SHARE_DOWNSTREAM) {
3504 /* In this case, 'logtext' is a local endpoint address */
3505 logeventf(ssh, "Using existing shared connection at %s", logtext);
3506 /* Also we should mention this in the console window to avoid
3507 * confusing users as to why this window doesn't behave the
3509 if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
3510 c_write_str(ssh,"Reusing a shared connection to this server.\r\n");
3512 } else if (event == SHARE_UPSTREAM) {
3513 /* In this case, 'logtext' is a local endpoint address too */
3514 logeventf(ssh, "Sharing this connection at %s", logtext);
3518 static int ssh_closing(Plug plug, const char *error_msg, int error_code,
3521 Ssh ssh = (Ssh) plug;
3522 int need_notify = ssh_do_close(ssh, FALSE);
3525 if (!ssh->close_expected)
3526 error_msg = "Server unexpectedly closed network connection";
3528 error_msg = "Server closed network connection";
3531 if (ssh->close_expected && ssh->clean_exit && ssh->exitcode < 0)
3535 notify_remote_exit(ssh->frontend);
3538 logevent(error_msg);
3539 if (!ssh->close_expected || !ssh->clean_exit)
3540 connection_fatal(ssh->frontend, "%s", error_msg);
3544 static int ssh_receive(Plug plug, int urgent, char *data, int len)
3546 Ssh ssh = (Ssh) plug;
3547 ssh_gotdata(ssh, (unsigned char *)data, len);
3548 if (ssh->state == SSH_STATE_CLOSED) {
3549 ssh_do_close(ssh, TRUE);
3555 static void ssh_sent(Plug plug, int bufsize)
3557 Ssh ssh = (Ssh) plug;
3559 * If the send backlog on the SSH socket itself clears, we
3560 * should unthrottle the whole world if it was throttled.
3562 if (bufsize < SSH_MAX_BACKLOG)
3563 ssh_throttle_all(ssh, 0, bufsize);
3566 static void ssh_hostport_setup(const char *host, int port, Conf *conf,
3567 char **savedhost, int *savedport,
3570 char *loghost = conf_get_str(conf, CONF_loghost);
3572 *loghost_ret = loghost;
3578 tmphost = dupstr(loghost);
3579 *savedport = 22; /* default ssh port */
3582 * A colon suffix on the hostname string also lets us affect
3583 * savedport. (Unless there are multiple colons, in which case
3584 * we assume this is an unbracketed IPv6 literal.)
3586 colon = host_strrchr(tmphost, ':');
3587 if (colon && colon == host_strchr(tmphost, ':')) {
3590 *savedport = atoi(colon);
3593 *savedhost = host_strduptrim(tmphost);
3596 *savedhost = host_strduptrim(host);
3598 port = 22; /* default ssh port */
3603 static int ssh_test_for_upstream(const char *host, int port, Conf *conf)
3609 random_ref(); /* platform may need this to determine share socket name */
3610 ssh_hostport_setup(host, port, conf, &savedhost, &savedport, NULL);
3611 ret = ssh_share_test_for_upstream(savedhost, savedport, conf);
3619 * Connect to specified host and port.
3620 * Returns an error message, or NULL on success.
3621 * Also places the canonical host name into `realhost'. It must be
3622 * freed by the caller.
3624 static const char *connect_to_host(Ssh ssh, const char *host, int port,
3625 char **realhost, int nodelay, int keepalive)
3627 static const struct plug_function_table fn_table = {
3638 int addressfamily, sshprot;
3640 ssh_hostport_setup(host, port, ssh->conf,
3641 &ssh->savedhost, &ssh->savedport, &loghost);
3643 ssh->fn = &fn_table; /* make 'ssh' usable as a Plug */
3646 * Try connection-sharing, in case that means we don't open a
3647 * socket after all. ssh_connection_sharing_init will connect to a
3648 * previously established upstream if it can, and failing that,
3649 * establish a listening socket for _us_ to be the upstream. In
3650 * the latter case it will return NULL just as if it had done
3651 * nothing, because here we only need to care if we're a
3652 * downstream and need to do our connection setup differently.
3654 ssh->connshare = NULL;
3655 ssh->attempting_connshare = TRUE; /* affects socket logging behaviour */
3656 ssh->s = ssh_connection_sharing_init(ssh->savedhost, ssh->savedport,
3657 ssh->conf, ssh, &ssh->connshare);
3658 ssh->attempting_connshare = FALSE;
3659 if (ssh->s != NULL) {
3661 * We are a downstream.
3663 ssh->bare_connection = TRUE;
3664 ssh->do_ssh_init = do_ssh_connection_init;
3665 ssh->fullhostname = NULL;
3666 *realhost = dupstr(host); /* best we can do */
3669 * We're not a downstream, so open a normal socket.
3671 ssh->do_ssh_init = do_ssh_init;
3676 addressfamily = conf_get_int(ssh->conf, CONF_addressfamily);
3677 logeventf(ssh, "Looking up host \"%s\"%s", host,
3678 (addressfamily == ADDRTYPE_IPV4 ? " (IPv4)" :
3679 (addressfamily == ADDRTYPE_IPV6 ? " (IPv6)" : "")));
3680 addr = name_lookup(host, port, realhost, ssh->conf, addressfamily);
3681 if ((err = sk_addr_error(addr)) != NULL) {
3685 ssh->fullhostname = dupstr(*realhost); /* save in case of GSSAPI */
3687 ssh->s = new_connection(addr, *realhost, port,
3688 0, 1, nodelay, keepalive,
3689 (Plug) ssh, ssh->conf);
3690 if ((err = sk_socket_error(ssh->s)) != NULL) {
3692 notify_remote_exit(ssh->frontend);
3698 * If the SSH version number's fixed, set it now, and if it's SSH-2,
3699 * send the version string too.
3701 sshprot = conf_get_int(ssh->conf, CONF_sshprot);
3704 if (sshprot == 3 && !ssh->bare_connection) {
3706 ssh_send_verstring(ssh, "SSH-", NULL);
3710 * loghost, if configured, overrides realhost.
3714 *realhost = dupstr(loghost);
3721 * Throttle or unthrottle the SSH connection.
3723 static void ssh_throttle_conn(Ssh ssh, int adjust)
3725 int old_count = ssh->conn_throttle_count;
3726 ssh->conn_throttle_count += adjust;
3727 assert(ssh->conn_throttle_count >= 0);
3728 if (ssh->conn_throttle_count && !old_count) {
3729 ssh_set_frozen(ssh, 1);
3730 } else if (!ssh->conn_throttle_count && old_count) {
3731 ssh_set_frozen(ssh, 0);
3736 * Throttle or unthrottle _all_ local data streams (for when sends
3737 * on the SSH connection itself back up).
3739 static void ssh_throttle_all(Ssh ssh, int enable, int bufsize)
3742 struct ssh_channel *c;
3744 if (enable == ssh->throttled_all)
3746 ssh->throttled_all = enable;
3747 ssh->overall_bufsize = bufsize;
3750 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
3752 case CHAN_MAINSESSION:
3754 * This is treated separately, outside the switch.
3758 x11_override_throttle(c->u.x11.xconn, enable);
3761 /* Agent channels require no buffer management. */
3764 pfd_override_throttle(c->u.pfd.pf, enable);
3770 static void ssh_agent_callback(void *sshv, void *reply, int replylen)
3772 Ssh ssh = (Ssh) sshv;
3774 ssh->agent_response = reply;
3775 ssh->agent_response_len = replylen;
3777 if (ssh->version == 1)
3778 do_ssh1_login(ssh, NULL, -1, NULL);
3780 do_ssh2_authconn(ssh, NULL, -1, NULL);
3783 static void ssh_dialog_callback(void *sshv, int ret)
3785 Ssh ssh = (Ssh) sshv;
3787 ssh->user_response = ret;
3789 if (ssh->version == 1)
3790 do_ssh1_login(ssh, NULL, -1, NULL);
3792 do_ssh2_transport(ssh, NULL, -1, NULL);
3795 * This may have unfrozen the SSH connection, so do a
3798 ssh_process_queued_incoming_data(ssh);
3801 static void ssh_agentf_callback(void *cv, void *reply, int replylen)
3803 struct ssh_channel *c = (struct ssh_channel *)cv;
3805 const void *sentreply = reply;
3807 c->u.a.outstanding_requests--;
3809 /* Fake SSH_AGENT_FAILURE. */
3810 sentreply = "\0\0\0\1\5";
3813 if (ssh->version == 2) {
3814 ssh2_add_channel_data(c, sentreply, replylen);
3817 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
3818 PKT_INT, c->remoteid,
3820 PKT_DATA, sentreply, replylen,
3826 * If we've already seen an incoming EOF but haven't sent an
3827 * outgoing one, this may be the moment to send it.
3829 if (c->u.a.outstanding_requests == 0 && (c->closes & CLOSES_RCVD_EOF))
3830 sshfwd_write_eof(c);
3834 * Client-initiated disconnection. Send a DISCONNECT if `wire_reason'
3835 * non-NULL, otherwise just close the connection. `client_reason' == NULL
3836 * => log `wire_reason'.
3838 static void ssh_disconnect(Ssh ssh, const char *client_reason,
3839 const char *wire_reason,
3840 int code, int clean_exit)
3844 client_reason = wire_reason;
3846 error = dupprintf("Disconnected: %s", client_reason);
3848 error = dupstr("Disconnected");
3850 if (ssh->version == 1) {
3851 send_packet(ssh, SSH1_MSG_DISCONNECT, PKT_STR, wire_reason,
3853 } else if (ssh->version == 2) {
3854 struct Packet *pktout = ssh2_pkt_init(SSH2_MSG_DISCONNECT);
3855 ssh2_pkt_adduint32(pktout, code);
3856 ssh2_pkt_addstring(pktout, wire_reason);
3857 ssh2_pkt_addstring(pktout, "en"); /* language tag */
3858 ssh2_pkt_send_noqueue(ssh, pktout);
3861 ssh->close_expected = TRUE;
3862 ssh->clean_exit = clean_exit;
3863 ssh_closing((Plug)ssh, error, 0, 0);
3867 int verify_ssh_manual_host_key(Ssh ssh, const char *fingerprint,
3868 const struct ssh_signkey *ssh2keytype,
3871 if (!conf_get_str_nthstrkey(ssh->conf, CONF_ssh_manual_hostkeys, 0)) {
3872 return -1; /* no manual keys configured */
3877 * The fingerprint string we've been given will have things
3878 * like 'ssh-rsa 2048' at the front of it. Strip those off and
3879 * narrow down to just the colon-separated hex block at the
3880 * end of the string.
3882 const char *p = strrchr(fingerprint, ' ');
3883 fingerprint = p ? p+1 : fingerprint;
3884 /* Quick sanity checks, including making sure it's in lowercase */
3885 assert(strlen(fingerprint) == 16*3 - 1);
3886 assert(fingerprint[2] == ':');
3887 assert(fingerprint[strspn(fingerprint, "0123456789abcdef:")] == 0);
3889 if (conf_get_str_str_opt(ssh->conf, CONF_ssh_manual_hostkeys,
3891 return 1; /* success */
3896 * Construct the base64-encoded public key blob and see if
3899 unsigned char *binblob;
3901 int binlen, atoms, i;
3902 binblob = ssh2keytype->public_blob(ssh2keydata, &binlen);
3903 atoms = (binlen + 2) / 3;
3904 base64blob = snewn(atoms * 4 + 1, char);
3905 for (i = 0; i < atoms; i++)
3906 base64_encode_atom(binblob + 3*i, binlen - 3*i, base64blob + 4*i);
3907 base64blob[atoms * 4] = '\0';
3909 if (conf_get_str_str_opt(ssh->conf, CONF_ssh_manual_hostkeys,
3912 return 1; /* success */
3921 * Handle the key exchange and user authentication phases.
3923 static int do_ssh1_login(Ssh ssh, const unsigned char *in, int inlen,
3924 struct Packet *pktin)
3927 unsigned char cookie[8], *ptr;
3928 struct MD5Context md5c;
3929 struct do_ssh1_login_state {
3932 unsigned char *rsabuf;
3933 const unsigned char *keystr1, *keystr2;
3934 unsigned long supported_ciphers_mask, supported_auths_mask;
3935 int tried_publickey, tried_agent;
3936 int tis_auth_refused, ccard_auth_refused;
3937 unsigned char session_id[16];
3939 void *publickey_blob;
3940 int publickey_bloblen;
3941 char *publickey_comment;
3942 int privatekey_available, privatekey_encrypted;
3943 prompts_t *cur_prompt;
3946 unsigned char request[5], *response, *p;
3956 struct RSAKey servkey, hostkey;
3958 crState(do_ssh1_login_state);
3965 if (pktin->type != SSH1_SMSG_PUBLIC_KEY) {
3966 bombout(("Public key packet not received"));
3970 logevent("Received public keys");
3972 ptr = ssh_pkt_getdata(pktin, 8);
3974 bombout(("SSH-1 public key packet stopped before random cookie"));
3977 memcpy(cookie, ptr, 8);
3979 if (!ssh1_pkt_getrsakey(pktin, &s->servkey, &s->keystr1) ||
3980 !ssh1_pkt_getrsakey(pktin, &s->hostkey, &s->keystr2)) {
3981 bombout(("Failed to read SSH-1 public keys from public key packet"));
3986 * Log the host key fingerprint.
3990 logevent("Host key fingerprint is:");
3991 strcpy(logmsg, " ");
3992 s->hostkey.comment = NULL;
3993 rsa_fingerprint(logmsg + strlen(logmsg),
3994 sizeof(logmsg) - strlen(logmsg), &s->hostkey);
3998 ssh->v1_remote_protoflags = ssh_pkt_getuint32(pktin);
3999 s->supported_ciphers_mask = ssh_pkt_getuint32(pktin);
4000 s->supported_auths_mask = ssh_pkt_getuint32(pktin);
4001 if ((ssh->remote_bugs & BUG_CHOKES_ON_RSA))
4002 s->supported_auths_mask &= ~(1 << SSH1_AUTH_RSA);
4004 ssh->v1_local_protoflags =
4005 ssh->v1_remote_protoflags & SSH1_PROTOFLAGS_SUPPORTED;
4006 ssh->v1_local_protoflags |= SSH1_PROTOFLAG_SCREEN_NUMBER;
4009 MD5Update(&md5c, s->keystr2, s->hostkey.bytes);
4010 MD5Update(&md5c, s->keystr1, s->servkey.bytes);
4011 MD5Update(&md5c, cookie, 8);
4012 MD5Final(s->session_id, &md5c);
4014 for (i = 0; i < 32; i++)
4015 ssh->session_key[i] = random_byte();
4018 * Verify that the `bits' and `bytes' parameters match.
4020 if (s->hostkey.bits > s->hostkey.bytes * 8 ||
4021 s->servkey.bits > s->servkey.bytes * 8) {
4022 bombout(("SSH-1 public keys were badly formatted"));
4026 s->len = (s->hostkey.bytes > s->servkey.bytes ?
4027 s->hostkey.bytes : s->servkey.bytes);
4029 s->rsabuf = snewn(s->len, unsigned char);
4032 * Verify the host key.
4036 * First format the key into a string.
4038 int len = rsastr_len(&s->hostkey);
4039 char fingerprint[100];
4040 char *keystr = snewn(len, char);
4041 rsastr_fmt(keystr, &s->hostkey);
4042 rsa_fingerprint(fingerprint, sizeof(fingerprint), &s->hostkey);
4044 /* First check against manually configured host keys. */
4045 s->dlgret = verify_ssh_manual_host_key(ssh, fingerprint, NULL, NULL);
4046 if (s->dlgret == 0) { /* did not match */
4047 bombout(("Host key did not appear in manually configured list"));
4050 } else if (s->dlgret < 0) { /* none configured; use standard handling */
4051 ssh_set_frozen(ssh, 1);
4052 s->dlgret = verify_ssh_host_key(ssh->frontend,
4053 ssh->savedhost, ssh->savedport,
4054 "rsa", keystr, fingerprint,
4055 ssh_dialog_callback, ssh);
4060 if (s->dlgret < 0) {
4064 bombout(("Unexpected data from server while waiting"
4065 " for user host key response"));
4068 } while (pktin || inlen > 0);
4069 s->dlgret = ssh->user_response;
4071 ssh_set_frozen(ssh, 0);
4073 if (s->dlgret == 0) {
4074 ssh_disconnect(ssh, "User aborted at host key verification",
4083 for (i = 0; i < 32; i++) {
4084 s->rsabuf[i] = ssh->session_key[i];
4086 s->rsabuf[i] ^= s->session_id[i];
4089 if (s->hostkey.bytes > s->servkey.bytes) {
4090 ret = rsaencrypt(s->rsabuf, 32, &s->servkey);
4092 ret = rsaencrypt(s->rsabuf, s->servkey.bytes, &s->hostkey);
4094 ret = rsaencrypt(s->rsabuf, 32, &s->hostkey);
4096 ret = rsaencrypt(s->rsabuf, s->hostkey.bytes, &s->servkey);
4099 bombout(("SSH-1 public key encryptions failed due to bad formatting"));
4103 logevent("Encrypted session key");
4106 int cipher_chosen = 0, warn = 0;
4107 const char *cipher_string = NULL;
4109 for (i = 0; !cipher_chosen && i < CIPHER_MAX; i++) {
4110 int next_cipher = conf_get_int_int(ssh->conf,
4111 CONF_ssh_cipherlist, i);
4112 if (next_cipher == CIPHER_WARN) {
4113 /* If/when we choose a cipher, warn about it */
4115 } else if (next_cipher == CIPHER_AES) {
4116 /* XXX Probably don't need to mention this. */
4117 logevent("AES not supported in SSH-1, skipping");
4119 switch (next_cipher) {
4120 case CIPHER_3DES: s->cipher_type = SSH_CIPHER_3DES;
4121 cipher_string = "3DES"; break;
4122 case CIPHER_BLOWFISH: s->cipher_type = SSH_CIPHER_BLOWFISH;
4123 cipher_string = "Blowfish"; break;
4124 case CIPHER_DES: s->cipher_type = SSH_CIPHER_DES;
4125 cipher_string = "single-DES"; break;
4127 if (s->supported_ciphers_mask & (1 << s->cipher_type))
4131 if (!cipher_chosen) {
4132 if ((s->supported_ciphers_mask & (1 << SSH_CIPHER_3DES)) == 0)
4133 bombout(("Server violates SSH-1 protocol by not "
4134 "supporting 3DES encryption"));
4136 /* shouldn't happen */
4137 bombout(("No supported ciphers found"));
4141 /* Warn about chosen cipher if necessary. */
4143 ssh_set_frozen(ssh, 1);
4144 s->dlgret = askalg(ssh->frontend, "cipher", cipher_string,
4145 ssh_dialog_callback, ssh);
4146 if (s->dlgret < 0) {
4150 bombout(("Unexpected data from server while waiting"
4151 " for user response"));
4154 } while (pktin || inlen > 0);
4155 s->dlgret = ssh->user_response;
4157 ssh_set_frozen(ssh, 0);
4158 if (s->dlgret == 0) {
4159 ssh_disconnect(ssh, "User aborted at cipher warning", NULL,
4166 switch (s->cipher_type) {
4167 case SSH_CIPHER_3DES:
4168 logevent("Using 3DES encryption");
4170 case SSH_CIPHER_DES:
4171 logevent("Using single-DES encryption");
4173 case SSH_CIPHER_BLOWFISH:
4174 logevent("Using Blowfish encryption");
4178 send_packet(ssh, SSH1_CMSG_SESSION_KEY,
4179 PKT_CHAR, s->cipher_type,
4180 PKT_DATA, cookie, 8,
4181 PKT_CHAR, (s->len * 8) >> 8, PKT_CHAR, (s->len * 8) & 0xFF,
4182 PKT_DATA, s->rsabuf, s->len,
4183 PKT_INT, ssh->v1_local_protoflags, PKT_END);
4185 logevent("Trying to enable encryption...");
4189 ssh->cipher = (s->cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 :
4190 s->cipher_type == SSH_CIPHER_DES ? &ssh_des :
4192 ssh->v1_cipher_ctx = ssh->cipher->make_context();
4193 ssh->cipher->sesskey(ssh->v1_cipher_ctx, ssh->session_key);
4194 logeventf(ssh, "Initialised %s encryption", ssh->cipher->text_name);
4196 ssh->crcda_ctx = crcda_make_context();
4197 logevent("Installing CRC compensation attack detector");
4199 if (s->servkey.modulus) {
4200 sfree(s->servkey.modulus);
4201 s->servkey.modulus = NULL;
4203 if (s->servkey.exponent) {
4204 sfree(s->servkey.exponent);
4205 s->servkey.exponent = NULL;
4207 if (s->hostkey.modulus) {
4208 sfree(s->hostkey.modulus);
4209 s->hostkey.modulus = NULL;
4211 if (s->hostkey.exponent) {
4212 sfree(s->hostkey.exponent);
4213 s->hostkey.exponent = NULL;
4217 if (pktin->type != SSH1_SMSG_SUCCESS) {
4218 bombout(("Encryption not successfully enabled"));
4222 logevent("Successfully started encryption");
4224 fflush(stdout); /* FIXME eh? */
4226 if ((ssh->username = get_remote_username(ssh->conf)) == NULL) {
4227 int ret; /* need not be kept over crReturn */
4228 s->cur_prompt = new_prompts(ssh->frontend);
4229 s->cur_prompt->to_server = TRUE;
4230 s->cur_prompt->name = dupstr("SSH login name");
4231 add_prompt(s->cur_prompt, dupstr("login as: "), TRUE);
4232 ret = get_userpass_input(s->cur_prompt, NULL, 0);
4235 crWaitUntil(!pktin);
4236 ret = get_userpass_input(s->cur_prompt, in, inlen);
4241 * Failed to get a username. Terminate.
4243 free_prompts(s->cur_prompt);
4244 ssh_disconnect(ssh, "No username provided", NULL, 0, TRUE);
4247 ssh->username = dupstr(s->cur_prompt->prompts[0]->result);
4248 free_prompts(s->cur_prompt);
4251 send_packet(ssh, SSH1_CMSG_USER, PKT_STR, ssh->username, PKT_END);
4253 char *userlog = dupprintf("Sent username \"%s\"", ssh->username);
4255 if (flags & FLAG_INTERACTIVE &&
4256 (!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) {
4257 c_write_str(ssh, userlog);
4258 c_write_str(ssh, "\r\n");
4266 if ((s->supported_auths_mask & (1 << SSH1_AUTH_RSA)) == 0) {
4267 /* We must not attempt PK auth. Pretend we've already tried it. */
4268 s->tried_publickey = s->tried_agent = 1;
4270 s->tried_publickey = s->tried_agent = 0;
4272 s->tis_auth_refused = s->ccard_auth_refused = 0;
4274 * Load the public half of any configured keyfile for later use.
4276 s->keyfile = conf_get_filename(ssh->conf, CONF_keyfile);
4277 if (!filename_is_null(s->keyfile)) {
4279 logeventf(ssh, "Reading key file \"%.150s\"",
4280 filename_to_str(s->keyfile));
4281 keytype = key_type(s->keyfile);
4282 if (keytype == SSH_KEYTYPE_SSH1 ||
4283 keytype == SSH_KEYTYPE_SSH1_PUBLIC) {
4285 if (rsakey_pubblob(s->keyfile,
4286 &s->publickey_blob, &s->publickey_bloblen,
4287 &s->publickey_comment, &error)) {
4288 s->privatekey_available = (keytype == SSH_KEYTYPE_SSH1);
4289 if (!s->privatekey_available)
4290 logeventf(ssh, "Key file contains public key only");
4291 s->privatekey_encrypted = rsakey_encrypted(s->keyfile,
4295 logeventf(ssh, "Unable to load key (%s)", error);
4296 msgbuf = dupprintf("Unable to load key file "
4297 "\"%.150s\" (%s)\r\n",
4298 filename_to_str(s->keyfile),
4300 c_write_str(ssh, msgbuf);
4302 s->publickey_blob = NULL;
4306 logeventf(ssh, "Unable to use this key file (%s)",
4307 key_type_to_str(keytype));
4308 msgbuf = dupprintf("Unable to use key file \"%.150s\""
4310 filename_to_str(s->keyfile),
4311 key_type_to_str(keytype));
4312 c_write_str(ssh, msgbuf);
4314 s->publickey_blob = NULL;
4317 s->publickey_blob = NULL;
4319 while (pktin->type == SSH1_SMSG_FAILURE) {
4320 s->pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
4322 if (conf_get_int(ssh->conf, CONF_tryagent) && agent_exists() && !s->tried_agent) {
4324 * Attempt RSA authentication using Pageant.
4330 logevent("Pageant is running. Requesting keys.");
4332 /* Request the keys held by the agent. */
4333 PUT_32BIT(s->request, 1);
4334 s->request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES;
4335 if (!agent_query(s->request, 5, &r, &s->responselen,
4336 ssh_agent_callback, ssh)) {
4340 bombout(("Unexpected data from server while waiting"
4341 " for agent response"));
4344 } while (pktin || inlen > 0);
4345 r = ssh->agent_response;
4346 s->responselen = ssh->agent_response_len;
4348 s->response = (unsigned char *) r;
4349 if (s->response && s->responselen >= 5 &&
4350 s->response[4] == SSH1_AGENT_RSA_IDENTITIES_ANSWER) {
4351 s->p = s->response + 5;
4352 s->nkeys = toint(GET_32BIT(s->p));
4354 logeventf(ssh, "Pageant reported negative key count %d",
4359 logeventf(ssh, "Pageant has %d SSH-1 keys", s->nkeys);
4360 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
4361 unsigned char *pkblob = s->p;
4365 do { /* do while (0) to make breaking easy */
4366 n = ssh1_read_bignum
4367 (s->p, toint(s->responselen-(s->p-s->response)),
4372 n = ssh1_read_bignum
4373 (s->p, toint(s->responselen-(s->p-s->response)),
4378 if (s->responselen - (s->p-s->response) < 4)
4380 s->commentlen = toint(GET_32BIT(s->p));
4382 if (s->commentlen < 0 ||
4383 toint(s->responselen - (s->p-s->response)) <
4386 s->commentp = (char *)s->p;
4387 s->p += s->commentlen;
4391 logevent("Pageant key list packet was truncated");
4395 if (s->publickey_blob) {
4396 if (!memcmp(pkblob, s->publickey_blob,
4397 s->publickey_bloblen)) {
4398 logeventf(ssh, "Pageant key #%d matches "
4399 "configured key file", s->keyi);
4400 s->tried_publickey = 1;
4402 /* Skip non-configured key */
4405 logeventf(ssh, "Trying Pageant key #%d", s->keyi);
4406 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
4407 PKT_BIGNUM, s->key.modulus, PKT_END);
4409 if (pktin->type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
4410 logevent("Key refused");
4413 logevent("Received RSA challenge");
4414 if ((s->challenge = ssh1_pkt_getmp(pktin)) == NULL) {
4415 bombout(("Server's RSA challenge was badly formatted"));
4420 char *agentreq, *q, *ret;
4423 len = 1 + 4; /* message type, bit count */
4424 len += ssh1_bignum_length(s->key.exponent);
4425 len += ssh1_bignum_length(s->key.modulus);
4426 len += ssh1_bignum_length(s->challenge);
4427 len += 16; /* session id */
4428 len += 4; /* response format */
4429 agentreq = snewn(4 + len, char);
4430 PUT_32BIT(agentreq, len);
4432 *q++ = SSH1_AGENTC_RSA_CHALLENGE;
4433 PUT_32BIT(q, bignum_bitcount(s->key.modulus));
4435 q += ssh1_write_bignum(q, s->key.exponent);
4436 q += ssh1_write_bignum(q, s->key.modulus);
4437 q += ssh1_write_bignum(q, s->challenge);
4438 memcpy(q, s->session_id, 16);
4440 PUT_32BIT(q, 1); /* response format */
4441 if (!agent_query(agentreq, len + 4, &vret, &retlen,
4442 ssh_agent_callback, ssh)) {
4447 bombout(("Unexpected data from server"
4448 " while waiting for agent"
4452 } while (pktin || inlen > 0);
4453 vret = ssh->agent_response;
4454 retlen = ssh->agent_response_len;
4459 if (ret[4] == SSH1_AGENT_RSA_RESPONSE) {
4460 logevent("Sending Pageant's response");
4461 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
4462 PKT_DATA, ret + 5, 16,
4466 if (pktin->type == SSH1_SMSG_SUCCESS) {
4468 ("Pageant's response accepted");
4469 if (flags & FLAG_VERBOSE) {
4470 c_write_str(ssh, "Authenticated using"
4472 c_write(ssh, s->commentp,
4474 c_write_str(ssh, "\" from agent\r\n");
4479 ("Pageant's response not accepted");
4482 ("Pageant failed to answer challenge");
4486 logevent("No reply received from Pageant");
4489 freebn(s->key.exponent);
4490 freebn(s->key.modulus);
4491 freebn(s->challenge);
4496 if (s->publickey_blob && !s->tried_publickey)
4497 logevent("Configured key file not in Pageant");
4499 logevent("Failed to get reply from Pageant");
4504 if (s->publickey_blob && s->privatekey_available &&
4505 !s->tried_publickey) {
4507 * Try public key authentication with the specified
4510 int got_passphrase; /* need not be kept over crReturn */
4511 if (flags & FLAG_VERBOSE)
4512 c_write_str(ssh, "Trying public key authentication.\r\n");
4513 s->keyfile = conf_get_filename(ssh->conf, CONF_keyfile);
4514 logeventf(ssh, "Trying public key \"%s\"",
4515 filename_to_str(s->keyfile));
4516 s->tried_publickey = 1;
4517 got_passphrase = FALSE;
4518 while (!got_passphrase) {
4520 * Get a passphrase, if necessary.
4522 char *passphrase = NULL; /* only written after crReturn */
4524 if (!s->privatekey_encrypted) {
4525 if (flags & FLAG_VERBOSE)
4526 c_write_str(ssh, "No passphrase required.\r\n");
4529 int ret; /* need not be kept over crReturn */
4530 s->cur_prompt = new_prompts(ssh->frontend);
4531 s->cur_prompt->to_server = FALSE;
4532 s->cur_prompt->name = dupstr("SSH key passphrase");
4533 add_prompt(s->cur_prompt,
4534 dupprintf("Passphrase for key \"%.100s\": ",
4535 s->publickey_comment), FALSE);
4536 ret = get_userpass_input(s->cur_prompt, NULL, 0);
4539 crWaitUntil(!pktin);
4540 ret = get_userpass_input(s->cur_prompt, in, inlen);
4544 /* Failed to get a passphrase. Terminate. */
4545 free_prompts(s->cur_prompt);
4546 ssh_disconnect(ssh, NULL, "Unable to authenticate",
4550 passphrase = dupstr(s->cur_prompt->prompts[0]->result);
4551 free_prompts(s->cur_prompt);
4554 * Try decrypting key with passphrase.
4556 s->keyfile = conf_get_filename(ssh->conf, CONF_keyfile);
4557 ret = loadrsakey(s->keyfile, &s->key, passphrase,
4560 smemclr(passphrase, strlen(passphrase));
4564 /* Correct passphrase. */
4565 got_passphrase = TRUE;
4566 } else if (ret == 0) {
4567 c_write_str(ssh, "Couldn't load private key from ");
4568 c_write_str(ssh, filename_to_str(s->keyfile));
4569 c_write_str(ssh, " (");
4570 c_write_str(ssh, error);
4571 c_write_str(ssh, ").\r\n");
4572 got_passphrase = FALSE;
4573 break; /* go and try something else */
4574 } else if (ret == -1) {
4575 c_write_str(ssh, "Wrong passphrase.\r\n"); /* FIXME */
4576 got_passphrase = FALSE;
4579 assert(0 && "unexpected return from loadrsakey()");
4580 got_passphrase = FALSE; /* placate optimisers */
4584 if (got_passphrase) {
4587 * Send a public key attempt.
4589 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
4590 PKT_BIGNUM, s->key.modulus, PKT_END);
4593 if (pktin->type == SSH1_SMSG_FAILURE) {
4594 c_write_str(ssh, "Server refused our public key.\r\n");
4595 continue; /* go and try something else */
4597 if (pktin->type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
4598 bombout(("Bizarre response to offer of public key"));
4604 unsigned char buffer[32];
4605 Bignum challenge, response;
4607 if ((challenge = ssh1_pkt_getmp(pktin)) == NULL) {
4608 bombout(("Server's RSA challenge was badly formatted"));
4611 response = rsadecrypt(challenge, &s->key);
4612 freebn(s->key.private_exponent);/* burn the evidence */
4614 for (i = 0; i < 32; i++) {
4615 buffer[i] = bignum_byte(response, 31 - i);
4619 MD5Update(&md5c, buffer, 32);
4620 MD5Update(&md5c, s->session_id, 16);
4621 MD5Final(buffer, &md5c);
4623 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
4624 PKT_DATA, buffer, 16, PKT_END);
4631 if (pktin->type == SSH1_SMSG_FAILURE) {
4632 if (flags & FLAG_VERBOSE)
4633 c_write_str(ssh, "Failed to authenticate with"
4634 " our public key.\r\n");
4635 continue; /* go and try something else */
4636 } else if (pktin->type != SSH1_SMSG_SUCCESS) {
4637 bombout(("Bizarre response to RSA authentication response"));
4641 break; /* we're through! */
4647 * Otherwise, try various forms of password-like authentication.
4649 s->cur_prompt = new_prompts(ssh->frontend);
4651 if (conf_get_int(ssh->conf, CONF_try_tis_auth) &&
4652 (s->supported_auths_mask & (1 << SSH1_AUTH_TIS)) &&
4653 !s->tis_auth_refused) {
4654 s->pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
4655 logevent("Requested TIS authentication");
4656 send_packet(ssh, SSH1_CMSG_AUTH_TIS, PKT_END);
4658 if (pktin->type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
4659 logevent("TIS authentication declined");
4660 if (flags & FLAG_INTERACTIVE)
4661 c_write_str(ssh, "TIS authentication refused.\r\n");
4662 s->tis_auth_refused = 1;
4667 char *instr_suf, *prompt;
4669 ssh_pkt_getstring(pktin, &challenge, &challengelen);
4671 bombout(("TIS challenge packet was badly formed"));
4674 logevent("Received TIS challenge");
4675 s->cur_prompt->to_server = TRUE;
4676 s->cur_prompt->name = dupstr("SSH TIS authentication");
4677 /* Prompt heuristic comes from OpenSSH */
4678 if (memchr(challenge, '\n', challengelen)) {
4679 instr_suf = dupstr("");
4680 prompt = dupprintf("%.*s", challengelen, challenge);
4682 instr_suf = dupprintf("%.*s", challengelen, challenge);
4683 prompt = dupstr("Response: ");
4685 s->cur_prompt->instruction =
4686 dupprintf("Using TIS authentication.%s%s",
4687 (*instr_suf) ? "\n" : "",
4689 s->cur_prompt->instr_reqd = TRUE;
4690 add_prompt(s->cur_prompt, prompt, FALSE);
4694 if (conf_get_int(ssh->conf, CONF_try_tis_auth) &&
4695 (s->supported_auths_mask & (1 << SSH1_AUTH_CCARD)) &&
4696 !s->ccard_auth_refused) {
4697 s->pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE;
4698 logevent("Requested CryptoCard authentication");
4699 send_packet(ssh, SSH1_CMSG_AUTH_CCARD, PKT_END);
4701 if (pktin->type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
4702 logevent("CryptoCard authentication declined");
4703 c_write_str(ssh, "CryptoCard authentication refused.\r\n");
4704 s->ccard_auth_refused = 1;
4709 char *instr_suf, *prompt;
4711 ssh_pkt_getstring(pktin, &challenge, &challengelen);
4713 bombout(("CryptoCard challenge packet was badly formed"));
4716 logevent("Received CryptoCard challenge");
4717 s->cur_prompt->to_server = TRUE;
4718 s->cur_prompt->name = dupstr("SSH CryptoCard authentication");
4719 s->cur_prompt->name_reqd = FALSE;
4720 /* Prompt heuristic comes from OpenSSH */
4721 if (memchr(challenge, '\n', challengelen)) {
4722 instr_suf = dupstr("");
4723 prompt = dupprintf("%.*s", challengelen, challenge);
4725 instr_suf = dupprintf("%.*s", challengelen, challenge);
4726 prompt = dupstr("Response: ");
4728 s->cur_prompt->instruction =
4729 dupprintf("Using CryptoCard authentication.%s%s",
4730 (*instr_suf) ? "\n" : "",
4732 s->cur_prompt->instr_reqd = TRUE;
4733 add_prompt(s->cur_prompt, prompt, FALSE);
4737 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
4738 if ((s->supported_auths_mask & (1 << SSH1_AUTH_PASSWORD)) == 0) {
4739 bombout(("No supported authentication methods available"));
4742 s->cur_prompt->to_server = TRUE;
4743 s->cur_prompt->name = dupstr("SSH password");
4744 add_prompt(s->cur_prompt, dupprintf("%s@%s's password: ",
4745 ssh->username, ssh->savedhost),
4750 * Show password prompt, having first obtained it via a TIS
4751 * or CryptoCard exchange if we're doing TIS or CryptoCard
4755 int ret; /* need not be kept over crReturn */
4756 ret = get_userpass_input(s->cur_prompt, NULL, 0);
4759 crWaitUntil(!pktin);
4760 ret = get_userpass_input(s->cur_prompt, in, inlen);
4765 * Failed to get a password (for example
4766 * because one was supplied on the command line
4767 * which has already failed to work). Terminate.
4769 free_prompts(s->cur_prompt);
4770 ssh_disconnect(ssh, NULL, "Unable to authenticate", 0, TRUE);
4775 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
4777 * Defence against traffic analysis: we send a
4778 * whole bunch of packets containing strings of
4779 * different lengths. One of these strings is the
4780 * password, in a SSH1_CMSG_AUTH_PASSWORD packet.
4781 * The others are all random data in
4782 * SSH1_MSG_IGNORE packets. This way a passive
4783 * listener can't tell which is the password, and
4784 * hence can't deduce the password length.
4786 * Anybody with a password length greater than 16
4787 * bytes is going to have enough entropy in their
4788 * password that a listener won't find it _that_
4789 * much help to know how long it is. So what we'll
4792 * - if password length < 16, we send 15 packets
4793 * containing string lengths 1 through 15
4795 * - otherwise, we let N be the nearest multiple
4796 * of 8 below the password length, and send 8
4797 * packets containing string lengths N through
4798 * N+7. This won't obscure the order of
4799 * magnitude of the password length, but it will
4800 * introduce a bit of extra uncertainty.
4802 * A few servers can't deal with SSH1_MSG_IGNORE, at
4803 * least in this context. For these servers, we need
4804 * an alternative defence. We make use of the fact
4805 * that the password is interpreted as a C string:
4806 * so we can append a NUL, then some random data.
4808 * A few servers can deal with neither SSH1_MSG_IGNORE
4809 * here _nor_ a padded password string.
4810 * For these servers we are left with no defences
4811 * against password length sniffing.
4813 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE) &&
4814 !(ssh->remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) {
4816 * The server can deal with SSH1_MSG_IGNORE, so
4817 * we can use the primary defence.
4819 int bottom, top, pwlen, i;
4822 pwlen = strlen(s->cur_prompt->prompts[0]->result);
4824 bottom = 0; /* zero length passwords are OK! :-) */
4827 bottom = pwlen & ~7;
4831 assert(pwlen >= bottom && pwlen <= top);
4833 randomstr = snewn(top + 1, char);
4835 for (i = bottom; i <= top; i++) {
4837 defer_packet(ssh, s->pwpkt_type,
4838 PKT_STR,s->cur_prompt->prompts[0]->result,
4841 for (j = 0; j < i; j++) {
4843 randomstr[j] = random_byte();
4844 } while (randomstr[j] == '\0');
4846 randomstr[i] = '\0';
4847 defer_packet(ssh, SSH1_MSG_IGNORE,
4848 PKT_STR, randomstr, PKT_END);
4851 logevent("Sending password with camouflage packets");
4852 ssh_pkt_defersend(ssh);
4855 else if (!(ssh->remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) {
4857 * The server can't deal with SSH1_MSG_IGNORE
4858 * but can deal with padded passwords, so we
4859 * can use the secondary defence.
4865 len = strlen(s->cur_prompt->prompts[0]->result);
4866 if (len < sizeof(string)) {
4868 strcpy(string, s->cur_prompt->prompts[0]->result);
4869 len++; /* cover the zero byte */
4870 while (len < sizeof(string)) {
4871 string[len++] = (char) random_byte();
4874 ss = s->cur_prompt->prompts[0]->result;
4876 logevent("Sending length-padded password");
4877 send_packet(ssh, s->pwpkt_type,
4878 PKT_INT, len, PKT_DATA, ss, len,
4882 * The server is believed unable to cope with
4883 * any of our password camouflage methods.
4886 len = strlen(s->cur_prompt->prompts[0]->result);
4887 logevent("Sending unpadded password");
4888 send_packet(ssh, s->pwpkt_type,
4890 PKT_DATA, s->cur_prompt->prompts[0]->result, len,
4894 send_packet(ssh, s->pwpkt_type,
4895 PKT_STR, s->cur_prompt->prompts[0]->result,
4898 logevent("Sent password");
4899 free_prompts(s->cur_prompt);
4901 if (pktin->type == SSH1_SMSG_FAILURE) {
4902 if (flags & FLAG_VERBOSE)
4903 c_write_str(ssh, "Access denied\r\n");
4904 logevent("Authentication refused");
4905 } else if (pktin->type != SSH1_SMSG_SUCCESS) {
4906 bombout(("Strange packet received, type %d", pktin->type));
4912 if (s->publickey_blob) {
4913 sfree(s->publickey_blob);
4914 sfree(s->publickey_comment);
4917 logevent("Authentication successful");
4922 static void ssh_channel_try_eof(struct ssh_channel *c)
4925 assert(c->pending_eof); /* precondition for calling us */
4927 return; /* can't close: not even opened yet */
4928 if (ssh->version == 2 && bufchain_size(&c->v.v2.outbuffer) > 0)
4929 return; /* can't send EOF: pending outgoing data */
4931 c->pending_eof = FALSE; /* we're about to send it */
4932 if (ssh->version == 1) {
4933 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid,
4935 c->closes |= CLOSES_SENT_EOF;
4937 struct Packet *pktout;
4938 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_EOF);
4939 ssh2_pkt_adduint32(pktout, c->remoteid);
4940 ssh2_pkt_send(ssh, pktout);
4941 c->closes |= CLOSES_SENT_EOF;
4942 ssh2_channel_check_close(c);
4946 Conf *sshfwd_get_conf(struct ssh_channel *c)
4952 void sshfwd_write_eof(struct ssh_channel *c)
4956 if (ssh->state == SSH_STATE_CLOSED)
4959 if (c->closes & CLOSES_SENT_EOF)
4962 c->pending_eof = TRUE;
4963 ssh_channel_try_eof(c);
4966 void sshfwd_unclean_close(struct ssh_channel *c, const char *err)
4970 if (ssh->state == SSH_STATE_CLOSED)
4975 x11_close(c->u.x11.xconn);
4976 logeventf(ssh, "Forwarded X11 connection terminated due to local "
4980 case CHAN_SOCKDATA_DORMANT:
4981 pfd_close(c->u.pfd.pf);
4982 logeventf(ssh, "Forwarded port closed due to local error: %s", err);
4985 c->type = CHAN_ZOMBIE;
4986 c->pending_eof = FALSE; /* this will confuse a zombie channel */
4988 ssh2_channel_check_close(c);
4991 int sshfwd_write(struct ssh_channel *c, char *buf, int len)
4995 if (ssh->state == SSH_STATE_CLOSED)
4998 if (ssh->version == 1) {
4999 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
5000 PKT_INT, c->remoteid,
5001 PKT_INT, len, PKT_DATA, buf, len,
5004 * In SSH-1 we can return 0 here - implying that forwarded
5005 * connections are never individually throttled - because
5006 * the only circumstance that can cause throttling will be
5007 * the whole SSH connection backing up, in which case
5008 * _everything_ will be throttled as a whole.
5012 ssh2_add_channel_data(c, buf, len);
5013 return ssh2_try_send(c);
5017 void sshfwd_unthrottle(struct ssh_channel *c, int bufsize)
5022 if (ssh->state == SSH_STATE_CLOSED)
5025 if (ssh->version == 1) {
5026 buflimit = SSH1_BUFFER_LIMIT;
5028 buflimit = c->v.v2.locmaxwin;
5029 ssh2_set_window(c, bufsize < buflimit ? buflimit - bufsize : 0);
5031 if (c->throttling_conn && bufsize <= buflimit) {
5032 c->throttling_conn = 0;
5033 ssh_throttle_conn(ssh, -1);
5037 static void ssh_queueing_handler(Ssh ssh, struct Packet *pktin)
5039 struct queued_handler *qh = ssh->qhead;
5043 assert(pktin->type == qh->msg1 || pktin->type == qh->msg2);
5046 assert(ssh->packet_dispatch[qh->msg1] == ssh_queueing_handler);
5047 ssh->packet_dispatch[qh->msg1] = ssh->q_saved_handler1;
5050 assert(ssh->packet_dispatch[qh->msg2] == ssh_queueing_handler);
5051 ssh->packet_dispatch[qh->msg2] = ssh->q_saved_handler2;
5055 ssh->qhead = qh->next;
5057 if (ssh->qhead->msg1 > 0) {
5058 ssh->q_saved_handler1 = ssh->packet_dispatch[ssh->qhead->msg1];
5059 ssh->packet_dispatch[ssh->qhead->msg1] = ssh_queueing_handler;
5061 if (ssh->qhead->msg2 > 0) {
5062 ssh->q_saved_handler2 = ssh->packet_dispatch[ssh->qhead->msg2];
5063 ssh->packet_dispatch[ssh->qhead->msg2] = ssh_queueing_handler;
5066 ssh->qhead = ssh->qtail = NULL;
5069 qh->handler(ssh, pktin, qh->ctx);
5074 static void ssh_queue_handler(Ssh ssh, int msg1, int msg2,
5075 chandler_fn_t handler, void *ctx)
5077 struct queued_handler *qh;
5079 qh = snew(struct queued_handler);
5082 qh->handler = handler;
5086 if (ssh->qtail == NULL) {
5090 ssh->q_saved_handler1 = ssh->packet_dispatch[ssh->qhead->msg1];
5091 ssh->packet_dispatch[qh->msg1] = ssh_queueing_handler;
5094 ssh->q_saved_handler2 = ssh->packet_dispatch[ssh->qhead->msg2];
5095 ssh->packet_dispatch[qh->msg2] = ssh_queueing_handler;
5098 ssh->qtail->next = qh;
5103 static void ssh_rportfwd_succfail(Ssh ssh, struct Packet *pktin, void *ctx)
5105 struct ssh_rportfwd *rpf, *pf = (struct ssh_rportfwd *)ctx;
5107 if (pktin->type == (ssh->version == 1 ? SSH1_SMSG_SUCCESS :
5108 SSH2_MSG_REQUEST_SUCCESS)) {
5109 logeventf(ssh, "Remote port forwarding from %s enabled",
5112 logeventf(ssh, "Remote port forwarding from %s refused",
5115 rpf = del234(ssh->rportfwds, pf);
5117 pf->pfrec->remote = NULL;
5122 int ssh_alloc_sharing_rportfwd(Ssh ssh, const char *shost, int sport,
5125 struct ssh_rportfwd *pf = snew(struct ssh_rportfwd);
5128 pf->share_ctx = share_ctx;
5129 pf->shost = dupstr(shost);
5131 pf->sportdesc = NULL;
5132 if (!ssh->rportfwds) {
5133 assert(ssh->version == 2);
5134 ssh->rportfwds = newtree234(ssh_rportcmp_ssh2);
5136 if (add234(ssh->rportfwds, pf) != pf) {
5144 static void ssh_sharing_global_request_response(Ssh ssh, struct Packet *pktin,
5147 share_got_pkt_from_server(ctx, pktin->type,
5148 pktin->body, pktin->length);
5151 void ssh_sharing_queue_global_request(Ssh ssh, void *share_ctx)
5153 ssh_queue_handler(ssh, SSH2_MSG_REQUEST_SUCCESS, SSH2_MSG_REQUEST_FAILURE,
5154 ssh_sharing_global_request_response, share_ctx);
5157 static void ssh_setup_portfwd(Ssh ssh, Conf *conf)
5159 struct ssh_portfwd *epf;
5163 if (!ssh->portfwds) {
5164 ssh->portfwds = newtree234(ssh_portcmp);
5167 * Go through the existing port forwardings and tag them
5168 * with status==DESTROY. Any that we want to keep will be
5169 * re-enabled (status==KEEP) as we go through the
5170 * configuration and find out which bits are the same as
5173 struct ssh_portfwd *epf;
5175 for (i = 0; (epf = index234(ssh->portfwds, i)) != NULL; i++)
5176 epf->status = DESTROY;
5179 for (val = conf_get_str_strs(conf, CONF_portfwd, NULL, &key);
5181 val = conf_get_str_strs(conf, CONF_portfwd, key, &key)) {
5182 char *kp, *kp2, *vp, *vp2;
5183 char address_family, type;
5184 int sport,dport,sserv,dserv;
5185 char *sports, *dports, *saddr, *host;
5189 address_family = 'A';
5191 if (*kp == 'A' || *kp == '4' || *kp == '6')
5192 address_family = *kp++;
5193 if (*kp == 'L' || *kp == 'R')
5196 if ((kp2 = host_strchr(kp, ':')) != NULL) {
5198 * There's a colon in the middle of the source port
5199 * string, which means that the part before it is
5200 * actually a source address.
5202 char *saddr_tmp = dupprintf("%.*s", (int)(kp2 - kp), kp);
5203 saddr = host_strduptrim(saddr_tmp);
5210 sport = atoi(sports);
5214 sport = net_service_lookup(sports);
5216 logeventf(ssh, "Service lookup failed for source"
5217 " port \"%s\"", sports);
5221 if (type == 'L' && !strcmp(val, "D")) {
5222 /* dynamic forwarding */
5229 /* ordinary forwarding */
5231 vp2 = vp + host_strcspn(vp, ":");
5232 host = dupprintf("%.*s", (int)(vp2 - vp), vp);
5236 dport = atoi(dports);
5240 dport = net_service_lookup(dports);
5242 logeventf(ssh, "Service lookup failed for destination"
5243 " port \"%s\"", dports);
5248 if (sport && dport) {
5249 /* Set up a description of the source port. */
5250 struct ssh_portfwd *pfrec, *epfrec;
5252 pfrec = snew(struct ssh_portfwd);
5254 pfrec->saddr = saddr;
5255 pfrec->sserv = sserv ? dupstr(sports) : NULL;
5256 pfrec->sport = sport;
5257 pfrec->daddr = host;
5258 pfrec->dserv = dserv ? dupstr(dports) : NULL;
5259 pfrec->dport = dport;
5260 pfrec->local = NULL;
5261 pfrec->remote = NULL;
5262 pfrec->addressfamily = (address_family == '4' ? ADDRTYPE_IPV4 :
5263 address_family == '6' ? ADDRTYPE_IPV6 :
5266 epfrec = add234(ssh->portfwds, pfrec);
5267 if (epfrec != pfrec) {
5268 if (epfrec->status == DESTROY) {
5270 * We already have a port forwarding up and running
5271 * with precisely these parameters. Hence, no need
5272 * to do anything; simply re-tag the existing one
5275 epfrec->status = KEEP;
5278 * Anything else indicates that there was a duplicate
5279 * in our input, which we'll silently ignore.
5281 free_portfwd(pfrec);
5283 pfrec->status = CREATE;
5292 * Now go through and destroy any port forwardings which were
5295 for (i = 0; (epf = index234(ssh->portfwds, i)) != NULL; i++)
5296 if (epf->status == DESTROY) {
5299 message = dupprintf("%s port forwarding from %s%s%d",
5300 epf->type == 'L' ? "local" :
5301 epf->type == 'R' ? "remote" : "dynamic",
5302 epf->saddr ? epf->saddr : "",
5303 epf->saddr ? ":" : "",
5306 if (epf->type != 'D') {
5307 char *msg2 = dupprintf("%s to %s:%d", message,
5308 epf->daddr, epf->dport);
5313 logeventf(ssh, "Cancelling %s", message);
5316 /* epf->remote or epf->local may be NULL if setting up a
5317 * forwarding failed. */
5319 struct ssh_rportfwd *rpf = epf->remote;
5320 struct Packet *pktout;
5323 * Cancel the port forwarding at the server
5326 if (ssh->version == 1) {
5328 * We cannot cancel listening ports on the
5329 * server side in SSH-1! There's no message
5330 * to support it. Instead, we simply remove
5331 * the rportfwd record from the local end
5332 * so that any connections the server tries
5333 * to make on it are rejected.
5336 pktout = ssh2_pkt_init(SSH2_MSG_GLOBAL_REQUEST);
5337 ssh2_pkt_addstring(pktout, "cancel-tcpip-forward");
5338 ssh2_pkt_addbool(pktout, 0);/* _don't_ want reply */
5340 ssh2_pkt_addstring(pktout, epf->saddr);
5341 } else if (conf_get_int(conf, CONF_rport_acceptall)) {
5342 /* XXX: rport_acceptall may not represent
5343 * what was used to open the original connection,
5344 * since it's reconfigurable. */
5345 ssh2_pkt_addstring(pktout, "");
5347 ssh2_pkt_addstring(pktout, "localhost");
5349 ssh2_pkt_adduint32(pktout, epf->sport);
5350 ssh2_pkt_send(ssh, pktout);
5353 del234(ssh->rportfwds, rpf);
5355 } else if (epf->local) {
5356 pfl_terminate(epf->local);
5359 delpos234(ssh->portfwds, i);
5361 i--; /* so we don't skip one in the list */
5365 * And finally, set up any new port forwardings (status==CREATE).
5367 for (i = 0; (epf = index234(ssh->portfwds, i)) != NULL; i++)
5368 if (epf->status == CREATE) {
5369 char *sportdesc, *dportdesc;
5370 sportdesc = dupprintf("%s%s%s%s%d%s",
5371 epf->saddr ? epf->saddr : "",
5372 epf->saddr ? ":" : "",
5373 epf->sserv ? epf->sserv : "",
5374 epf->sserv ? "(" : "",
5376 epf->sserv ? ")" : "");
5377 if (epf->type == 'D') {
5380 dportdesc = dupprintf("%s:%s%s%d%s",
5382 epf->dserv ? epf->dserv : "",
5383 epf->dserv ? "(" : "",
5385 epf->dserv ? ")" : "");
5388 if (epf->type == 'L') {
5389 char *err = pfl_listen(epf->daddr, epf->dport,
5390 epf->saddr, epf->sport,
5391 ssh, conf, &epf->local,
5392 epf->addressfamily);
5394 logeventf(ssh, "Local %sport %s forwarding to %s%s%s",
5395 epf->addressfamily == ADDRTYPE_IPV4 ? "IPv4 " :
5396 epf->addressfamily == ADDRTYPE_IPV6 ? "IPv6 " : "",
5397 sportdesc, dportdesc,
5398 err ? " failed: " : "", err ? err : "");
5401 } else if (epf->type == 'D') {
5402 char *err = pfl_listen(NULL, -1, epf->saddr, epf->sport,
5403 ssh, conf, &epf->local,
5404 epf->addressfamily);
5406 logeventf(ssh, "Local %sport %s SOCKS dynamic forwarding%s%s",
5407 epf->addressfamily == ADDRTYPE_IPV4 ? "IPv4 " :
5408 epf->addressfamily == ADDRTYPE_IPV6 ? "IPv6 " : "",
5410 err ? " failed: " : "", err ? err : "");
5415 struct ssh_rportfwd *pf;
5418 * Ensure the remote port forwardings tree exists.
5420 if (!ssh->rportfwds) {
5421 if (ssh->version == 1)
5422 ssh->rportfwds = newtree234(ssh_rportcmp_ssh1);
5424 ssh->rportfwds = newtree234(ssh_rportcmp_ssh2);
5427 pf = snew(struct ssh_rportfwd);
5428 pf->share_ctx = NULL;
5429 pf->dhost = dupstr(epf->daddr);
5430 pf->dport = epf->dport;
5432 pf->shost = dupstr(epf->saddr);
5433 } else if (conf_get_int(conf, CONF_rport_acceptall)) {
5434 pf->shost = dupstr("");
5436 pf->shost = dupstr("localhost");
5438 pf->sport = epf->sport;
5439 if (add234(ssh->rportfwds, pf) != pf) {
5440 logeventf(ssh, "Duplicate remote port forwarding to %s:%d",
5441 epf->daddr, epf->dport);
5444 logeventf(ssh, "Requesting remote port %s"
5445 " forward to %s", sportdesc, dportdesc);
5447 pf->sportdesc = sportdesc;
5452 if (ssh->version == 1) {
5453 send_packet(ssh, SSH1_CMSG_PORT_FORWARD_REQUEST,
5454 PKT_INT, epf->sport,
5455 PKT_STR, epf->daddr,
5456 PKT_INT, epf->dport,
5458 ssh_queue_handler(ssh, SSH1_SMSG_SUCCESS,
5460 ssh_rportfwd_succfail, pf);
5462 struct Packet *pktout;
5463 pktout = ssh2_pkt_init(SSH2_MSG_GLOBAL_REQUEST);
5464 ssh2_pkt_addstring(pktout, "tcpip-forward");
5465 ssh2_pkt_addbool(pktout, 1);/* want reply */
5466 ssh2_pkt_addstring(pktout, pf->shost);
5467 ssh2_pkt_adduint32(pktout, pf->sport);
5468 ssh2_pkt_send(ssh, pktout);
5470 ssh_queue_handler(ssh, SSH2_MSG_REQUEST_SUCCESS,
5471 SSH2_MSG_REQUEST_FAILURE,
5472 ssh_rportfwd_succfail, pf);
5481 static void ssh1_smsg_stdout_stderr_data(Ssh ssh, struct Packet *pktin)
5484 int stringlen, bufsize;
5486 ssh_pkt_getstring(pktin, &string, &stringlen);
5487 if (string == NULL) {
5488 bombout(("Incoming terminal data packet was badly formed"));
5492 bufsize = from_backend(ssh->frontend, pktin->type == SSH1_SMSG_STDERR_DATA,
5494 if (!ssh->v1_stdout_throttling && bufsize > SSH1_BUFFER_LIMIT) {
5495 ssh->v1_stdout_throttling = 1;
5496 ssh_throttle_conn(ssh, +1);
5500 static void ssh1_smsg_x11_open(Ssh ssh, struct Packet *pktin)
5502 /* Remote side is trying to open a channel to talk to our
5503 * X-Server. Give them back a local channel number. */
5504 struct ssh_channel *c;
5505 int remoteid = ssh_pkt_getuint32(pktin);
5507 logevent("Received X11 connect request");
5508 /* Refuse if X11 forwarding is disabled. */
5509 if (!ssh->X11_fwd_enabled) {
5510 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
5511 PKT_INT, remoteid, PKT_END);
5512 logevent("Rejected X11 connect request");
5514 c = snew(struct ssh_channel);
5517 c->u.x11.xconn = x11_init(ssh->x11authtree, c, NULL, -1);
5518 c->remoteid = remoteid;
5519 c->halfopen = FALSE;
5520 c->localid = alloc_channel_id(ssh);
5522 c->pending_eof = FALSE;
5523 c->throttling_conn = 0;
5524 c->type = CHAN_X11; /* identify channel type */
5525 add234(ssh->channels, c);
5526 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
5527 PKT_INT, c->remoteid, PKT_INT,
5528 c->localid, PKT_END);
5529 logevent("Opened X11 forward channel");
5533 static void ssh1_smsg_agent_open(Ssh ssh, struct Packet *pktin)
5535 /* Remote side is trying to open a channel to talk to our
5536 * agent. Give them back a local channel number. */
5537 struct ssh_channel *c;
5538 int remoteid = ssh_pkt_getuint32(pktin);
5540 /* Refuse if agent forwarding is disabled. */
5541 if (!ssh->agentfwd_enabled) {
5542 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
5543 PKT_INT, remoteid, PKT_END);
5545 c = snew(struct ssh_channel);
5547 c->remoteid = remoteid;
5548 c->halfopen = FALSE;
5549 c->localid = alloc_channel_id(ssh);
5551 c->pending_eof = FALSE;
5552 c->throttling_conn = 0;
5553 c->type = CHAN_AGENT; /* identify channel type */
5554 c->u.a.lensofar = 0;
5555 c->u.a.message = NULL;
5556 c->u.a.outstanding_requests = 0;
5557 add234(ssh->channels, c);
5558 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
5559 PKT_INT, c->remoteid, PKT_INT, c->localid,
5564 static void ssh1_msg_port_open(Ssh ssh, struct Packet *pktin)
5566 /* Remote side is trying to open a channel to talk to a
5567 * forwarded port. Give them back a local channel number. */
5568 struct ssh_rportfwd pf, *pfp;
5574 remoteid = ssh_pkt_getuint32(pktin);
5575 ssh_pkt_getstring(pktin, &host, &hostsize);
5576 port = ssh_pkt_getuint32(pktin);
5578 pf.dhost = dupprintf("%.*s", hostsize, host);
5580 pfp = find234(ssh->rportfwds, &pf, NULL);
5583 logeventf(ssh, "Rejected remote port open request for %s:%d",
5585 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
5586 PKT_INT, remoteid, PKT_END);
5588 struct ssh_channel *c = snew(struct ssh_channel);
5591 logeventf(ssh, "Received remote port open request for %s:%d",
5593 err = pfd_connect(&c->u.pfd.pf, pf.dhost, port,
5594 c, ssh->conf, pfp->pfrec->addressfamily);
5596 logeventf(ssh, "Port open failed: %s", err);
5599 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
5600 PKT_INT, remoteid, PKT_END);
5602 c->remoteid = remoteid;
5603 c->halfopen = FALSE;
5604 c->localid = alloc_channel_id(ssh);
5606 c->pending_eof = FALSE;
5607 c->throttling_conn = 0;
5608 c->type = CHAN_SOCKDATA; /* identify channel type */
5609 add234(ssh->channels, c);
5610 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
5611 PKT_INT, c->remoteid, PKT_INT,
5612 c->localid, PKT_END);
5613 logevent("Forwarded port opened successfully");
5620 static void ssh1_msg_channel_open_confirmation(Ssh ssh, struct Packet *pktin)
5622 unsigned int remoteid = ssh_pkt_getuint32(pktin);
5623 unsigned int localid = ssh_pkt_getuint32(pktin);
5624 struct ssh_channel *c;
5626 c = find234(ssh->channels, &remoteid, ssh_channelfind);
5627 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
5628 c->remoteid = localid;
5629 c->halfopen = FALSE;
5630 c->type = CHAN_SOCKDATA;
5631 c->throttling_conn = 0;
5632 pfd_confirm(c->u.pfd.pf);
5635 if (c && c->pending_eof) {
5637 * We have a pending close on this channel,
5638 * which we decided on before the server acked
5639 * the channel open. So now we know the
5640 * remoteid, we can close it again.
5642 ssh_channel_try_eof(c);
5646 static void ssh1_msg_channel_open_failure(Ssh ssh, struct Packet *pktin)
5648 unsigned int remoteid = ssh_pkt_getuint32(pktin);
5649 struct ssh_channel *c;
5651 c = find234(ssh->channels, &remoteid, ssh_channelfind);
5652 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
5653 logevent("Forwarded connection refused by server");
5654 pfd_close(c->u.pfd.pf);
5655 del234(ssh->channels, c);
5660 static void ssh1_msg_channel_close(Ssh ssh, struct Packet *pktin)
5662 /* Remote side closes a channel. */
5663 unsigned i = ssh_pkt_getuint32(pktin);
5664 struct ssh_channel *c;
5665 c = find234(ssh->channels, &i, ssh_channelfind);
5666 if (c && !c->halfopen) {
5668 if (pktin->type == SSH1_MSG_CHANNEL_CLOSE &&
5669 !(c->closes & CLOSES_RCVD_EOF)) {
5671 * Received CHANNEL_CLOSE, which we translate into
5674 int send_close = FALSE;
5676 c->closes |= CLOSES_RCVD_EOF;
5681 x11_send_eof(c->u.x11.xconn);
5687 pfd_send_eof(c->u.pfd.pf);
5696 if (send_close && !(c->closes & CLOSES_SENT_EOF)) {
5697 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid,
5699 c->closes |= CLOSES_SENT_EOF;
5703 if (pktin->type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION &&
5704 !(c->closes & CLOSES_RCVD_CLOSE)) {
5706 if (!(c->closes & CLOSES_SENT_EOF)) {
5707 bombout(("Received CHANNEL_CLOSE_CONFIRMATION for channel %d"
5708 " for which we never sent CHANNEL_CLOSE\n", i));
5711 c->closes |= CLOSES_RCVD_CLOSE;
5714 if (!((CLOSES_SENT_EOF | CLOSES_RCVD_EOF) & ~c->closes) &&
5715 !(c->closes & CLOSES_SENT_CLOSE)) {
5716 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION,
5717 PKT_INT, c->remoteid, PKT_END);
5718 c->closes |= CLOSES_SENT_CLOSE;
5721 if (!((CLOSES_SENT_CLOSE | CLOSES_RCVD_CLOSE) & ~c->closes))
5722 ssh_channel_destroy(c);
5724 bombout(("Received CHANNEL_CLOSE%s for %s channel %d\n",
5725 pktin->type == SSH1_MSG_CHANNEL_CLOSE ? "" :
5726 "_CONFIRMATION", c ? "half-open" : "nonexistent",
5731 static void ssh1_msg_channel_data(Ssh ssh, struct Packet *pktin)
5733 /* Data sent down one of our channels. */
5734 int i = ssh_pkt_getuint32(pktin);
5737 struct ssh_channel *c;
5739 ssh_pkt_getstring(pktin, &p, &len);
5741 c = find234(ssh->channels, &i, ssh_channelfind);
5746 bufsize = x11_send(c->u.x11.xconn, p, len);
5749 bufsize = pfd_send(c->u.pfd.pf, p, len);
5752 /* Data for an agent message. Buffer it. */
5754 if (c->u.a.lensofar < 4) {
5755 unsigned int l = min(4 - c->u.a.lensofar, (unsigned)len);
5756 memcpy(c->u.a.msglen + c->u.a.lensofar, p,
5760 c->u.a.lensofar += l;
5762 if (c->u.a.lensofar == 4) {
5764 4 + GET_32BIT(c->u.a.msglen);
5765 c->u.a.message = snewn(c->u.a.totallen,
5767 memcpy(c->u.a.message, c->u.a.msglen, 4);
5769 if (c->u.a.lensofar >= 4 && len > 0) {
5771 min(c->u.a.totallen - c->u.a.lensofar,
5773 memcpy(c->u.a.message + c->u.a.lensofar, p,
5777 c->u.a.lensofar += l;
5779 if (c->u.a.lensofar == c->u.a.totallen) {
5782 c->u.a.outstanding_requests++;
5783 if (agent_query(c->u.a.message,
5786 ssh_agentf_callback, c))
5787 ssh_agentf_callback(c, reply, replylen);
5788 sfree(c->u.a.message);
5789 c->u.a.lensofar = 0;
5792 bufsize = 0; /* agent channels never back up */
5795 if (!c->throttling_conn && bufsize > SSH1_BUFFER_LIMIT) {
5796 c->throttling_conn = 1;
5797 ssh_throttle_conn(ssh, +1);
5802 static void ssh1_smsg_exit_status(Ssh ssh, struct Packet *pktin)
5804 ssh->exitcode = ssh_pkt_getuint32(pktin);
5805 logeventf(ssh, "Server sent command exit status %d", ssh->exitcode);
5806 send_packet(ssh, SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
5808 * In case `helpful' firewalls or proxies tack
5809 * extra human-readable text on the end of the
5810 * session which we might mistake for another
5811 * encrypted packet, we close the session once
5812 * we've sent EXIT_CONFIRMATION.
5814 ssh_disconnect(ssh, NULL, NULL, 0, TRUE);
5817 /* Helper function to deal with sending tty modes for REQUEST_PTY */
5818 static void ssh1_send_ttymode(void *data, char *mode, char *val)
5820 struct Packet *pktout = (struct Packet *)data;
5822 unsigned int arg = 0;
5823 while (strcmp(mode, ssh_ttymodes[i].mode) != 0) i++;
5824 if (i == lenof(ssh_ttymodes)) return;
5825 switch (ssh_ttymodes[i].type) {
5827 arg = ssh_tty_parse_specchar(val);
5830 arg = ssh_tty_parse_boolean(val);
5833 ssh2_pkt_addbyte(pktout, ssh_ttymodes[i].opcode);
5834 ssh2_pkt_addbyte(pktout, arg);
5837 int ssh_agent_forwarding_permitted(Ssh ssh)
5839 return conf_get_int(ssh->conf, CONF_agentfwd) && agent_exists();
5842 static void do_ssh1_connection(Ssh ssh, const unsigned char *in, int inlen,
5843 struct Packet *pktin)
5845 crBegin(ssh->do_ssh1_connection_crstate);
5847 ssh->packet_dispatch[SSH1_SMSG_STDOUT_DATA] =
5848 ssh->packet_dispatch[SSH1_SMSG_STDERR_DATA] =
5849 ssh1_smsg_stdout_stderr_data;
5851 ssh->packet_dispatch[SSH1_MSG_CHANNEL_OPEN_CONFIRMATION] =
5852 ssh1_msg_channel_open_confirmation;
5853 ssh->packet_dispatch[SSH1_MSG_CHANNEL_OPEN_FAILURE] =
5854 ssh1_msg_channel_open_failure;
5855 ssh->packet_dispatch[SSH1_MSG_CHANNEL_CLOSE] =
5856 ssh->packet_dispatch[SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION] =
5857 ssh1_msg_channel_close;
5858 ssh->packet_dispatch[SSH1_MSG_CHANNEL_DATA] = ssh1_msg_channel_data;
5859 ssh->packet_dispatch[SSH1_SMSG_EXIT_STATUS] = ssh1_smsg_exit_status;
5861 if (ssh_agent_forwarding_permitted(ssh)) {
5862 logevent("Requesting agent forwarding");
5863 send_packet(ssh, SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END);
5867 if (pktin->type != SSH1_SMSG_SUCCESS
5868 && pktin->type != SSH1_SMSG_FAILURE) {
5869 bombout(("Protocol confusion"));
5871 } else if (pktin->type == SSH1_SMSG_FAILURE) {
5872 logevent("Agent forwarding refused");
5874 logevent("Agent forwarding enabled");
5875 ssh->agentfwd_enabled = TRUE;
5876 ssh->packet_dispatch[SSH1_SMSG_AGENT_OPEN] = ssh1_smsg_agent_open;
5880 if (conf_get_int(ssh->conf, CONF_x11_forward)) {
5882 x11_setup_display(conf_get_str(ssh->conf, CONF_x11_display),
5884 if (!ssh->x11disp) {
5885 /* FIXME: return an error message from x11_setup_display */
5886 logevent("X11 forwarding not enabled: unable to"
5887 " initialise X display");
5889 ssh->x11auth = x11_invent_fake_auth
5890 (ssh->x11authtree, conf_get_int(ssh->conf, CONF_x11_auth));
5891 ssh->x11auth->disp = ssh->x11disp;
5893 logevent("Requesting X11 forwarding");
5894 if (ssh->v1_local_protoflags & SSH1_PROTOFLAG_SCREEN_NUMBER) {
5895 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
5896 PKT_STR, ssh->x11auth->protoname,
5897 PKT_STR, ssh->x11auth->datastring,
5898 PKT_INT, ssh->x11disp->screennum,
5901 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
5902 PKT_STR, ssh->x11auth->protoname,
5903 PKT_STR, ssh->x11auth->datastring,
5909 if (pktin->type != SSH1_SMSG_SUCCESS
5910 && pktin->type != SSH1_SMSG_FAILURE) {
5911 bombout(("Protocol confusion"));
5913 } else if (pktin->type == SSH1_SMSG_FAILURE) {
5914 logevent("X11 forwarding refused");
5916 logevent("X11 forwarding enabled");
5917 ssh->X11_fwd_enabled = TRUE;
5918 ssh->packet_dispatch[SSH1_SMSG_X11_OPEN] = ssh1_smsg_x11_open;
5923 ssh_setup_portfwd(ssh, ssh->conf);
5924 ssh->packet_dispatch[SSH1_MSG_PORT_OPEN] = ssh1_msg_port_open;
5926 if (!conf_get_int(ssh->conf, CONF_nopty)) {
5928 /* Unpick the terminal-speed string. */
5929 /* XXX perhaps we should allow no speeds to be sent. */
5930 ssh->ospeed = 38400; ssh->ispeed = 38400; /* last-resort defaults */
5931 sscanf(conf_get_str(ssh->conf, CONF_termspeed), "%d,%d", &ssh->ospeed, &ssh->ispeed);
5932 /* Send the pty request. */
5933 pkt = ssh1_pkt_init(SSH1_CMSG_REQUEST_PTY);
5934 ssh_pkt_addstring(pkt, conf_get_str(ssh->conf, CONF_termtype));
5935 ssh_pkt_adduint32(pkt, ssh->term_height);
5936 ssh_pkt_adduint32(pkt, ssh->term_width);
5937 ssh_pkt_adduint32(pkt, 0); /* width in pixels */
5938 ssh_pkt_adduint32(pkt, 0); /* height in pixels */
5939 parse_ttymodes(ssh, ssh1_send_ttymode, (void *)pkt);
5940 ssh_pkt_addbyte(pkt, SSH1_TTY_OP_ISPEED);
5941 ssh_pkt_adduint32(pkt, ssh->ispeed);
5942 ssh_pkt_addbyte(pkt, SSH1_TTY_OP_OSPEED);
5943 ssh_pkt_adduint32(pkt, ssh->ospeed);
5944 ssh_pkt_addbyte(pkt, SSH_TTY_OP_END);
5946 ssh->state = SSH_STATE_INTERMED;
5950 if (pktin->type != SSH1_SMSG_SUCCESS
5951 && pktin->type != SSH1_SMSG_FAILURE) {
5952 bombout(("Protocol confusion"));
5954 } else if (pktin->type == SSH1_SMSG_FAILURE) {
5955 c_write_str(ssh, "Server refused to allocate pty\r\n");
5956 ssh->editing = ssh->echoing = 1;
5958 logeventf(ssh, "Allocated pty (ospeed %dbps, ispeed %dbps)",
5959 ssh->ospeed, ssh->ispeed);
5960 ssh->got_pty = TRUE;
5963 ssh->editing = ssh->echoing = 1;
5966 if (conf_get_int(ssh->conf, CONF_compression)) {
5967 send_packet(ssh, SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END);
5971 if (pktin->type != SSH1_SMSG_SUCCESS
5972 && pktin->type != SSH1_SMSG_FAILURE) {
5973 bombout(("Protocol confusion"));
5975 } else if (pktin->type == SSH1_SMSG_FAILURE) {
5976 c_write_str(ssh, "Server refused to compress\r\n");
5978 logevent("Started compression");
5979 ssh->v1_compressing = TRUE;
5980 ssh->cs_comp_ctx = zlib_compress_init();
5981 logevent("Initialised zlib (RFC1950) compression");
5982 ssh->sc_comp_ctx = zlib_decompress_init();
5983 logevent("Initialised zlib (RFC1950) decompression");
5987 * Start the shell or command.
5989 * Special case: if the first-choice command is an SSH-2
5990 * subsystem (hence not usable here) and the second choice
5991 * exists, we fall straight back to that.
5994 char *cmd = conf_get_str(ssh->conf, CONF_remote_cmd);
5996 if (conf_get_int(ssh->conf, CONF_ssh_subsys) &&
5997 conf_get_str(ssh->conf, CONF_remote_cmd2)) {
5998 cmd = conf_get_str(ssh->conf, CONF_remote_cmd2);
5999 ssh->fallback_cmd = TRUE;
6002 send_packet(ssh, SSH1_CMSG_EXEC_CMD, PKT_STR, cmd, PKT_END);
6004 send_packet(ssh, SSH1_CMSG_EXEC_SHELL, PKT_END);
6005 logevent("Started session");
6008 ssh->state = SSH_STATE_SESSION;
6009 if (ssh->size_needed)
6010 ssh_size(ssh, ssh->term_width, ssh->term_height);
6011 if (ssh->eof_needed)
6012 ssh_special(ssh, TS_EOF);
6015 ldisc_echoedit_update(ssh->ldisc); /* cause ldisc to notice changes */
6017 ssh->channels = newtree234(ssh_channelcmp);
6021 * By this point, most incoming packets are already being
6022 * handled by the dispatch table, and we need only pay
6023 * attention to the unusual ones.
6028 if (pktin->type == SSH1_SMSG_SUCCESS) {
6029 /* may be from EXEC_SHELL on some servers */
6030 } else if (pktin->type == SSH1_SMSG_FAILURE) {
6031 /* may be from EXEC_SHELL on some servers
6032 * if no pty is available or in other odd cases. Ignore */
6034 bombout(("Strange packet received: type %d", pktin->type));
6039 int len = min(inlen, 512);
6040 send_packet(ssh, SSH1_CMSG_STDIN_DATA,
6041 PKT_INT, len, PKT_DATA, in, len,
6053 * Handle the top-level SSH-2 protocol.
6055 static void ssh1_msg_debug(Ssh ssh, struct Packet *pktin)
6060 ssh_pkt_getstring(pktin, &msg, &msglen);
6061 logeventf(ssh, "Remote debug message: %.*s", msglen, msg);
6064 static void ssh1_msg_disconnect(Ssh ssh, struct Packet *pktin)
6066 /* log reason code in disconnect message */
6070 ssh_pkt_getstring(pktin, &msg, &msglen);
6071 bombout(("Server sent disconnect message:\n\"%.*s\"", msglen, msg));
6074 static void ssh_msg_ignore(Ssh ssh, struct Packet *pktin)
6076 /* Do nothing, because we're ignoring it! Duhh. */
6079 static void ssh1_protocol_setup(Ssh ssh)
6084 * Most messages are handled by the coroutines.
6086 for (i = 0; i < 256; i++)
6087 ssh->packet_dispatch[i] = NULL;
6090 * These special message types we install handlers for.
6092 ssh->packet_dispatch[SSH1_MSG_DISCONNECT] = ssh1_msg_disconnect;
6093 ssh->packet_dispatch[SSH1_MSG_IGNORE] = ssh_msg_ignore;
6094 ssh->packet_dispatch[SSH1_MSG_DEBUG] = ssh1_msg_debug;
6097 static void ssh1_protocol(Ssh ssh, const void *vin, int inlen,
6098 struct Packet *pktin)
6100 const unsigned char *in = (const unsigned char *)vin;
6101 if (ssh->state == SSH_STATE_CLOSED)
6104 if (pktin && ssh->packet_dispatch[pktin->type]) {
6105 ssh->packet_dispatch[pktin->type](ssh, pktin);
6109 if (!ssh->protocol_initial_phase_done) {
6110 if (do_ssh1_login(ssh, in, inlen, pktin))
6111 ssh->protocol_initial_phase_done = TRUE;
6116 do_ssh1_connection(ssh, in, inlen, pktin);
6120 * Utility routines for decoding comma-separated strings in KEXINIT.
6122 static int first_in_commasep_string(char const *needle, char const *haystack,
6126 if (!needle || !haystack) /* protect against null pointers */
6128 needlen = strlen(needle);
6130 if (haylen >= needlen && /* haystack is long enough */
6131 !memcmp(needle, haystack, needlen) && /* initial match */
6132 (haylen == needlen || haystack[needlen] == ',')
6133 /* either , or EOS follows */
6139 static int in_commasep_string(char const *needle, char const *haystack,
6144 if (!needle || !haystack) /* protect against null pointers */
6147 * Is it at the start of the string?
6149 if (first_in_commasep_string(needle, haystack, haylen))
6152 * If not, search for the next comma and resume after that.
6153 * If no comma found, terminate.
6155 p = memchr(haystack, ',', haylen);
6157 /* + 1 to skip over comma */
6158 return in_commasep_string(needle, p + 1, haylen - (p + 1 - haystack));
6162 * Add a value to the comma-separated string at the end of the packet.
6164 static void ssh2_pkt_addstring_commasep(struct Packet *pkt, const char *data)
6166 if (pkt->length - pkt->savedpos > 0)
6167 ssh_pkt_addstring_str(pkt, ",");
6168 ssh_pkt_addstring_str(pkt, data);
6173 * SSH-2 key derivation (RFC 4253 section 7.2).
6175 static unsigned char *ssh2_mkkey(Ssh ssh, Bignum K, unsigned char *H,
6176 char chr, int keylen)
6178 const struct ssh_hash *h = ssh->kex->hash;
6186 /* Round up to the next multiple of hash length. */
6187 keylen_padded = ((keylen + h->hlen - 1) / h->hlen) * h->hlen;
6189 key = snewn(keylen_padded, unsigned char);
6191 /* First hlen bytes. */
6193 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
6194 hash_mpint(h, s, K);
6195 h->bytes(s, H, h->hlen);
6196 h->bytes(s, &chr, 1);
6197 h->bytes(s, ssh->v2_session_id, ssh->v2_session_id_len);
6200 /* Subsequent blocks of hlen bytes. */
6201 if (keylen_padded > h->hlen) {
6205 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
6206 hash_mpint(h, s, K);
6207 h->bytes(s, H, h->hlen);
6209 for (offset = h->hlen; offset < keylen_padded; offset += h->hlen) {
6210 h->bytes(s, key + offset - h->hlen, h->hlen);
6212 h->final(s2, key + offset);
6218 /* Now clear any extra bytes of key material beyond the length
6219 * we're officially returning, because the caller won't know to
6221 if (keylen_padded > keylen)
6222 smemclr(key + keylen, keylen_padded - keylen);
6228 * Structure for constructing KEXINIT algorithm lists.
6230 #define MAXKEXLIST 16
6231 struct kexinit_algorithm {
6235 const struct ssh_kex *kex;
6238 const struct ssh_signkey *hostkey;
6240 const struct ssh2_cipher *cipher;
6244 const struct ssh_mac *mac;
6247 const struct ssh_compress *comp;
6252 * Find a slot in a KEXINIT algorithm list to use for a new algorithm.
6253 * If the algorithm is already in the list, return a pointer to its
6254 * entry, otherwise return an entry from the end of the list.
6255 * This assumes that every time a particular name is passed in, it
6256 * comes from the same string constant. If this isn't true, this
6257 * function may need to be rewritten to use strcmp() instead.
6259 static struct kexinit_algorithm *ssh2_kexinit_addalg(struct kexinit_algorithm
6260 *list, const char *name)
6264 for (i = 0; i < MAXKEXLIST; i++)
6265 if (list[i].name == NULL || list[i].name == name) {
6266 list[i].name = name;
6269 assert(!"No space in KEXINIT list");
6274 * Handle the SSH-2 transport layer.
6276 static void do_ssh2_transport(Ssh ssh, const void *vin, int inlen,
6277 struct Packet *pktin)
6279 const unsigned char *in = (const unsigned char *)vin;
6281 KEXLIST_KEX, KEXLIST_HOSTKEY, KEXLIST_CSCIPHER, KEXLIST_SCCIPHER,
6282 KEXLIST_CSMAC, KEXLIST_SCMAC, KEXLIST_CSCOMP, KEXLIST_SCCOMP,
6285 const char * kexlist_descr[NKEXLIST] = {
6286 "key exchange algorithm", "host key algorithm",
6287 "client-to-server cipher", "server-to-client cipher",
6288 "client-to-server MAC", "server-to-client MAC",
6289 "client-to-server compression method",
6290 "server-to-client compression method" };
6291 struct do_ssh2_transport_state {
6293 int nbits, pbits, warn_kex, warn_cscipher, warn_sccipher;
6294 Bignum p, g, e, f, K;
6297 int kex_init_value, kex_reply_value;
6298 const struct ssh_mac **maclist;
6300 const struct ssh2_cipher *cscipher_tobe;
6301 const struct ssh2_cipher *sccipher_tobe;
6302 const struct ssh_mac *csmac_tobe;
6303 const struct ssh_mac *scmac_tobe;
6304 int csmac_etm_tobe, scmac_etm_tobe;
6305 const struct ssh_compress *cscomp_tobe;
6306 const struct ssh_compress *sccomp_tobe;
6307 char *hostkeydata, *sigdata, *rsakeydata, *keystr, *fingerprint;
6308 int hostkeylen, siglen, rsakeylen;
6309 void *hkey; /* actual host key */
6310 void *rsakey; /* for RSA kex */
6311 void *eckey; /* for ECDH kex */
6312 unsigned char exchange_hash[SSH2_KEX_MAX_HASH_LEN];
6313 int n_preferred_kex;
6314 const struct ssh_kexes *preferred_kex[KEX_MAX];
6315 int n_preferred_ciphers;
6316 const struct ssh2_ciphers *preferred_ciphers[CIPHER_MAX];
6317 const struct ssh_compress *preferred_comp;
6318 int userauth_succeeded; /* for delayed compression */
6319 int pending_compression;
6320 int got_session_id, activated_authconn;
6321 struct Packet *pktout;
6325 struct kexinit_algorithm kexlists[NKEXLIST][MAXKEXLIST];
6327 crState(do_ssh2_transport_state);
6329 assert(!ssh->bare_connection);
6333 s->cscipher_tobe = s->sccipher_tobe = NULL;
6334 s->csmac_tobe = s->scmac_tobe = NULL;
6335 s->cscomp_tobe = s->sccomp_tobe = NULL;
6337 s->got_session_id = s->activated_authconn = FALSE;
6338 s->userauth_succeeded = FALSE;
6339 s->pending_compression = FALSE;
6342 * Be prepared to work around the buggy MAC problem.
6344 if (ssh->remote_bugs & BUG_SSH2_HMAC)
6345 s->maclist = buggymacs, s->nmacs = lenof(buggymacs);
6347 s->maclist = macs, s->nmacs = lenof(macs);
6350 ssh->pkt_kctx = SSH2_PKTCTX_NOKEX;
6353 struct kexinit_algorithm *alg;
6356 * Set up the preferred key exchange. (NULL => warn below here)
6358 s->n_preferred_kex = 0;
6359 for (i = 0; i < KEX_MAX; i++) {
6360 switch (conf_get_int_int(ssh->conf, CONF_ssh_kexlist, i)) {
6362 s->preferred_kex[s->n_preferred_kex++] =
6363 &ssh_diffiehellman_gex;
6366 s->preferred_kex[s->n_preferred_kex++] =
6367 &ssh_diffiehellman_group14;
6370 s->preferred_kex[s->n_preferred_kex++] =
6371 &ssh_diffiehellman_group1;
6374 s->preferred_kex[s->n_preferred_kex++] =
6378 s->preferred_kex[s->n_preferred_kex++] =
6382 /* Flag for later. Don't bother if it's the last in
6384 if (i < KEX_MAX - 1) {
6385 s->preferred_kex[s->n_preferred_kex++] = NULL;
6392 * Set up the preferred ciphers. (NULL => warn below here)
6394 s->n_preferred_ciphers = 0;
6395 for (i = 0; i < CIPHER_MAX; i++) {
6396 switch (conf_get_int_int(ssh->conf, CONF_ssh_cipherlist, i)) {
6397 case CIPHER_BLOWFISH:
6398 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_blowfish;
6401 if (conf_get_int(ssh->conf, CONF_ssh2_des_cbc)) {
6402 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_des;
6406 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_3des;
6409 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_aes;
6411 case CIPHER_ARCFOUR:
6412 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_arcfour;
6414 case CIPHER_CHACHA20:
6415 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_ccp;
6418 /* Flag for later. Don't bother if it's the last in
6420 if (i < CIPHER_MAX - 1) {
6421 s->preferred_ciphers[s->n_preferred_ciphers++] = NULL;
6428 * Set up preferred compression.
6430 if (conf_get_int(ssh->conf, CONF_compression))
6431 s->preferred_comp = &ssh_zlib;
6433 s->preferred_comp = &ssh_comp_none;
6436 * Enable queueing of outgoing auth- or connection-layer
6437 * packets while we are in the middle of a key exchange.
6439 ssh->queueing = TRUE;
6442 * Flag that KEX is in progress.
6444 ssh->kex_in_progress = TRUE;
6446 for (i = 0; i < NKEXLIST; i++)
6447 for (j = 0; j < MAXKEXLIST; j++)
6448 s->kexlists[i][j].name = NULL;
6449 /* List key exchange algorithms. */
6451 for (i = 0; i < s->n_preferred_kex; i++) {
6452 const struct ssh_kexes *k = s->preferred_kex[i];
6453 if (!k) warn = TRUE;
6454 else for (j = 0; j < k->nkexes; j++) {
6455 alg = ssh2_kexinit_addalg(s->kexlists[KEXLIST_KEX],
6457 alg->u.kex.kex = k->list[j];
6458 alg->u.kex.warn = warn;
6461 /* List server host key algorithms. */
6462 if (!s->got_session_id) {
6464 * In the first key exchange, we list all the algorithms
6465 * we're prepared to cope with, but prefer those algorithms
6466 * for which we have a host key for this host.
6468 for (i = 0; i < lenof(hostkey_algs); i++) {
6469 if (have_ssh_host_key(ssh->savedhost, ssh->savedport,
6470 hostkey_algs[i]->keytype)) {
6471 alg = ssh2_kexinit_addalg(s->kexlists[KEXLIST_HOSTKEY],
6472 hostkey_algs[i]->name);
6473 alg->u.hostkey = hostkey_algs[i];
6476 for (i = 0; i < lenof(hostkey_algs); i++) {
6477 alg = ssh2_kexinit_addalg(s->kexlists[KEXLIST_HOSTKEY],
6478 hostkey_algs[i]->name);
6479 alg->u.hostkey = hostkey_algs[i];
6483 * In subsequent key exchanges, we list only the kex
6484 * algorithm that was selected in the first key exchange,
6485 * so that we keep getting the same host key and hence
6486 * don't have to interrupt the user's session to ask for
6490 alg = ssh2_kexinit_addalg(s->kexlists[KEXLIST_HOSTKEY],
6491 ssh->hostkey->name);
6492 alg->u.hostkey = ssh->hostkey;
6494 /* List encryption algorithms (client->server then server->client). */
6495 for (k = KEXLIST_CSCIPHER; k <= KEXLIST_SCCIPHER; k++) {
6498 alg = ssh2_kexinit_addalg(s->kexlists[k], "none");
6499 alg->u.cipher.cipher = NULL;
6500 alg->u.cipher.warn = warn;
6501 #endif /* FUZZING */
6502 for (i = 0; i < s->n_preferred_ciphers; i++) {
6503 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
6504 if (!c) warn = TRUE;
6505 else for (j = 0; j < c->nciphers; j++) {
6506 alg = ssh2_kexinit_addalg(s->kexlists[k],
6508 alg->u.cipher.cipher = c->list[j];
6509 alg->u.cipher.warn = warn;
6513 /* List MAC algorithms (client->server then server->client). */
6514 for (j = KEXLIST_CSMAC; j <= KEXLIST_SCMAC; j++) {
6516 alg = ssh2_kexinit_addalg(s->kexlists[j], "none");
6517 alg->u.mac.mac = NULL;
6518 alg->u.mac.etm = FALSE;
6519 #endif /* FUZZING */
6520 for (i = 0; i < s->nmacs; i++) {
6521 alg = ssh2_kexinit_addalg(s->kexlists[j], s->maclist[i]->name);
6522 alg->u.mac.mac = s->maclist[i];
6523 alg->u.mac.etm = FALSE;
6525 for (i = 0; i < s->nmacs; i++)
6526 /* For each MAC, there may also be an ETM version,
6527 * which we list second. */
6528 if (s->maclist[i]->etm_name) {
6529 alg = ssh2_kexinit_addalg(s->kexlists[j],
6530 s->maclist[i]->etm_name);
6531 alg->u.mac.mac = s->maclist[i];
6532 alg->u.mac.etm = TRUE;
6535 /* List client->server compression algorithms,
6536 * then server->client compression algorithms. (We use the
6537 * same set twice.) */
6538 for (j = KEXLIST_CSCOMP; j <= KEXLIST_SCCOMP; j++) {
6539 assert(lenof(compressions) > 1);
6540 /* Prefer non-delayed versions */
6541 alg = ssh2_kexinit_addalg(s->kexlists[j], s->preferred_comp->name);
6542 alg->u.comp = s->preferred_comp;
6543 /* We don't even list delayed versions of algorithms until
6544 * they're allowed to be used, to avoid a race. See the end of
6546 if (s->userauth_succeeded && s->preferred_comp->delayed_name) {
6547 alg = ssh2_kexinit_addalg(s->kexlists[j],
6548 s->preferred_comp->delayed_name);
6549 alg->u.comp = s->preferred_comp;
6551 for (i = 0; i < lenof(compressions); i++) {
6552 const struct ssh_compress *c = compressions[i];
6553 alg = ssh2_kexinit_addalg(s->kexlists[j], c->name);
6555 if (s->userauth_succeeded && c->delayed_name) {
6556 alg = ssh2_kexinit_addalg(s->kexlists[j], c->delayed_name);
6562 * Construct and send our key exchange packet.
6564 s->pktout = ssh2_pkt_init(SSH2_MSG_KEXINIT);
6565 for (i = 0; i < 16; i++)
6566 ssh2_pkt_addbyte(s->pktout, (unsigned char) random_byte());
6567 for (i = 0; i < NKEXLIST; i++) {
6568 ssh2_pkt_addstring_start(s->pktout);
6569 for (j = 0; j < MAXKEXLIST; j++) {
6570 if (s->kexlists[i][j].name == NULL) break;
6571 ssh2_pkt_addstring_commasep(s->pktout, s->kexlists[i][j].name);
6574 /* List client->server languages. Empty list. */
6575 ssh2_pkt_addstring_start(s->pktout);
6576 /* List server->client languages. Empty list. */
6577 ssh2_pkt_addstring_start(s->pktout);
6578 /* First KEX packet does _not_ follow, because we're not that brave. */
6579 ssh2_pkt_addbool(s->pktout, FALSE);
6581 ssh2_pkt_adduint32(s->pktout, 0);
6584 s->our_kexinitlen = s->pktout->length - 5;
6585 s->our_kexinit = snewn(s->our_kexinitlen, unsigned char);
6586 memcpy(s->our_kexinit, s->pktout->data + 5, s->our_kexinitlen);
6588 ssh2_pkt_send_noqueue(ssh, s->pktout);
6591 crWaitUntilV(pktin);
6594 * Now examine the other side's KEXINIT to see what we're up
6601 if (pktin->type != SSH2_MSG_KEXINIT) {
6602 bombout(("expected key exchange packet from server"));
6606 ssh->hostkey = NULL;
6607 s->cscipher_tobe = NULL;
6608 s->sccipher_tobe = NULL;
6609 s->csmac_tobe = NULL;
6610 s->scmac_tobe = NULL;
6611 s->cscomp_tobe = NULL;
6612 s->sccomp_tobe = NULL;
6613 s->warn_kex = s->warn_cscipher = s->warn_sccipher = FALSE;
6615 pktin->savedpos += 16; /* skip garbage cookie */
6618 for (i = 0; i < NKEXLIST; i++) {
6619 ssh_pkt_getstring(pktin, &str, &len);
6621 bombout(("KEXINIT packet was incomplete"));
6625 /* If we've already selected a cipher which requires a
6626 * particular MAC, then just select that, and don't even
6627 * bother looking through the server's KEXINIT string for
6629 if (i == KEXLIST_CSMAC && s->cscipher_tobe &&
6630 s->cscipher_tobe->required_mac) {
6631 s->csmac_tobe = s->cscipher_tobe->required_mac;
6632 s->csmac_etm_tobe = !!(s->csmac_tobe->etm_name);
6635 if (i == KEXLIST_SCMAC && s->sccipher_tobe &&
6636 s->sccipher_tobe->required_mac) {
6637 s->scmac_tobe = s->sccipher_tobe->required_mac;
6638 s->scmac_etm_tobe = !!(s->scmac_tobe->etm_name);
6642 for (j = 0; j < MAXKEXLIST; j++) {
6643 struct kexinit_algorithm *alg = &s->kexlists[i][j];
6644 if (alg->name == NULL) break;
6645 if (in_commasep_string(alg->name, str, len)) {
6646 /* We've found a matching algorithm. */
6647 if (i == KEXLIST_KEX || i == KEXLIST_HOSTKEY) {
6648 /* Check if we might need to ignore first kex pkt */
6650 !first_in_commasep_string(alg->name, str, len))
6653 if (i == KEXLIST_KEX) {
6654 ssh->kex = alg->u.kex.kex;
6655 s->warn_kex = alg->u.kex.warn;
6656 } else if (i == KEXLIST_HOSTKEY) {
6657 ssh->hostkey = alg->u.hostkey;
6658 } else if (i == KEXLIST_CSCIPHER) {
6659 s->cscipher_tobe = alg->u.cipher.cipher;
6660 s->warn_cscipher = alg->u.cipher.warn;
6661 } else if (i == KEXLIST_SCCIPHER) {
6662 s->sccipher_tobe = alg->u.cipher.cipher;
6663 s->warn_sccipher = alg->u.cipher.warn;
6664 } else if (i == KEXLIST_CSMAC) {
6665 s->csmac_tobe = alg->u.mac.mac;
6666 s->csmac_etm_tobe = alg->u.mac.etm;
6667 } else if (i == KEXLIST_SCMAC) {
6668 s->scmac_tobe = alg->u.mac.mac;
6669 s->scmac_etm_tobe = alg->u.mac.etm;
6670 } else if (i == KEXLIST_CSCOMP) {
6671 s->cscomp_tobe = alg->u.comp;
6672 } else if (i == KEXLIST_SCCOMP) {
6673 s->sccomp_tobe = alg->u.comp;
6677 if ((i == KEXLIST_CSCOMP || i == KEXLIST_SCCOMP) &&
6678 in_commasep_string(alg->u.comp->delayed_name, str, len))
6679 s->pending_compression = TRUE; /* try this later */
6681 bombout(("Couldn't agree a %s ((available: %.*s)",
6682 kexlist_descr[i], len, str));
6687 if (s->pending_compression) {
6688 logevent("Server supports delayed compression; "
6689 "will try this later");
6691 ssh_pkt_getstring(pktin, &str, &len); /* client->server language */
6692 ssh_pkt_getstring(pktin, &str, &len); /* server->client language */
6693 s->ignorepkt = ssh2_pkt_getbool(pktin) && !s->guessok;
6695 ssh->exhash = ssh->kex->hash->init();
6696 hash_string(ssh->kex->hash, ssh->exhash, ssh->v_c, strlen(ssh->v_c));
6697 hash_string(ssh->kex->hash, ssh->exhash, ssh->v_s, strlen(ssh->v_s));
6698 hash_string(ssh->kex->hash, ssh->exhash,
6699 s->our_kexinit, s->our_kexinitlen);
6700 sfree(s->our_kexinit);
6701 /* Include the type byte in the hash of server's KEXINIT */
6702 hash_string(ssh->kex->hash, ssh->exhash,
6703 pktin->body - 1, pktin->length + 1);
6706 ssh_set_frozen(ssh, 1);
6707 s->dlgret = askalg(ssh->frontend, "key-exchange algorithm",
6709 ssh_dialog_callback, ssh);
6710 if (s->dlgret < 0) {
6714 bombout(("Unexpected data from server while"
6715 " waiting for user response"));
6718 } while (pktin || inlen > 0);
6719 s->dlgret = ssh->user_response;
6721 ssh_set_frozen(ssh, 0);
6722 if (s->dlgret == 0) {
6723 ssh_disconnect(ssh, "User aborted at kex warning", NULL,
6729 if (s->warn_cscipher) {
6730 ssh_set_frozen(ssh, 1);
6731 s->dlgret = askalg(ssh->frontend,
6732 "client-to-server cipher",
6733 s->cscipher_tobe->name,
6734 ssh_dialog_callback, ssh);
6735 if (s->dlgret < 0) {
6739 bombout(("Unexpected data from server while"
6740 " waiting for user response"));
6743 } while (pktin || inlen > 0);
6744 s->dlgret = ssh->user_response;
6746 ssh_set_frozen(ssh, 0);
6747 if (s->dlgret == 0) {
6748 ssh_disconnect(ssh, "User aborted at cipher warning", NULL,
6754 if (s->warn_sccipher) {
6755 ssh_set_frozen(ssh, 1);
6756 s->dlgret = askalg(ssh->frontend,
6757 "server-to-client cipher",
6758 s->sccipher_tobe->name,
6759 ssh_dialog_callback, ssh);
6760 if (s->dlgret < 0) {
6764 bombout(("Unexpected data from server while"
6765 " waiting for user response"));
6768 } while (pktin || inlen > 0);
6769 s->dlgret = ssh->user_response;
6771 ssh_set_frozen(ssh, 0);
6772 if (s->dlgret == 0) {
6773 ssh_disconnect(ssh, "User aborted at cipher warning", NULL,
6779 if (s->ignorepkt) /* first_kex_packet_follows */
6780 crWaitUntilV(pktin); /* Ignore packet */
6783 if (ssh->kex->main_type == KEXTYPE_DH) {
6785 * Work out the number of bits of key we will need from the
6786 * key exchange. We start with the maximum key length of
6792 csbits = s->cscipher_tobe ? s->cscipher_tobe->real_keybits : 0;
6793 scbits = s->sccipher_tobe ? s->sccipher_tobe->real_keybits : 0;
6794 s->nbits = (csbits > scbits ? csbits : scbits);
6796 /* The keys only have hlen-bit entropy, since they're based on
6797 * a hash. So cap the key size at hlen bits. */
6798 if (s->nbits > ssh->kex->hash->hlen * 8)
6799 s->nbits = ssh->kex->hash->hlen * 8;
6802 * If we're doing Diffie-Hellman group exchange, start by
6803 * requesting a group.
6805 if (dh_is_gex(ssh->kex)) {
6806 logevent("Doing Diffie-Hellman group exchange");
6807 ssh->pkt_kctx = SSH2_PKTCTX_DHGEX;
6809 * Work out how big a DH group we will need to allow that
6812 s->pbits = 512 << ((s->nbits - 1) / 64);
6813 if (s->pbits < DH_MIN_SIZE)
6814 s->pbits = DH_MIN_SIZE;
6815 if (s->pbits > DH_MAX_SIZE)
6816 s->pbits = DH_MAX_SIZE;
6817 if ((ssh->remote_bugs & BUG_SSH2_OLDGEX)) {
6818 s->pktout = ssh2_pkt_init(SSH2_MSG_KEX_DH_GEX_REQUEST_OLD);
6819 ssh2_pkt_adduint32(s->pktout, s->pbits);
6821 s->pktout = ssh2_pkt_init(SSH2_MSG_KEX_DH_GEX_REQUEST);
6822 ssh2_pkt_adduint32(s->pktout, DH_MIN_SIZE);
6823 ssh2_pkt_adduint32(s->pktout, s->pbits);
6824 ssh2_pkt_adduint32(s->pktout, DH_MAX_SIZE);
6826 ssh2_pkt_send_noqueue(ssh, s->pktout);
6828 crWaitUntilV(pktin);
6829 if (pktin->type != SSH2_MSG_KEX_DH_GEX_GROUP) {
6830 bombout(("expected key exchange group packet from server"));
6833 s->p = ssh2_pkt_getmp(pktin);
6834 s->g = ssh2_pkt_getmp(pktin);
6835 if (!s->p || !s->g) {
6836 bombout(("unable to read mp-ints from incoming group packet"));
6839 ssh->kex_ctx = dh_setup_gex(s->p, s->g);
6840 s->kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT;
6841 s->kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY;
6843 ssh->pkt_kctx = SSH2_PKTCTX_DHGROUP;
6844 ssh->kex_ctx = dh_setup_group(ssh->kex);
6845 s->kex_init_value = SSH2_MSG_KEXDH_INIT;
6846 s->kex_reply_value = SSH2_MSG_KEXDH_REPLY;
6847 logeventf(ssh, "Using Diffie-Hellman with standard group \"%s\"",
6848 ssh->kex->groupname);
6851 logeventf(ssh, "Doing Diffie-Hellman key exchange with hash %s",
6852 ssh->kex->hash->text_name);
6854 * Now generate and send e for Diffie-Hellman.
6856 set_busy_status(ssh->frontend, BUSY_CPU); /* this can take a while */
6857 s->e = dh_create_e(ssh->kex_ctx, s->nbits * 2);
6858 s->pktout = ssh2_pkt_init(s->kex_init_value);
6859 ssh2_pkt_addmp(s->pktout, s->e);
6860 ssh2_pkt_send_noqueue(ssh, s->pktout);
6862 set_busy_status(ssh->frontend, BUSY_WAITING); /* wait for server */
6863 crWaitUntilV(pktin);
6864 if (pktin->type != s->kex_reply_value) {
6865 bombout(("expected key exchange reply packet from server"));
6868 set_busy_status(ssh->frontend, BUSY_CPU); /* cogitate */
6869 ssh_pkt_getstring(pktin, &s->hostkeydata, &s->hostkeylen);
6870 if (!s->hostkeydata) {
6871 bombout(("unable to parse key exchange reply packet"));
6874 s->hkey = ssh->hostkey->newkey(ssh->hostkey,
6875 s->hostkeydata, s->hostkeylen);
6876 s->f = ssh2_pkt_getmp(pktin);
6878 bombout(("unable to parse key exchange reply packet"));
6881 ssh_pkt_getstring(pktin, &s->sigdata, &s->siglen);
6883 bombout(("unable to parse key exchange reply packet"));
6888 const char *err = dh_validate_f(ssh->kex_ctx, s->f);
6890 bombout(("key exchange reply failed validation: %s", err));
6894 s->K = dh_find_K(ssh->kex_ctx, s->f);
6896 /* We assume everything from now on will be quick, and it might
6897 * involve user interaction. */
6898 set_busy_status(ssh->frontend, BUSY_NOT);
6900 hash_string(ssh->kex->hash, ssh->exhash, s->hostkeydata, s->hostkeylen);
6901 if (dh_is_gex(ssh->kex)) {
6902 if (!(ssh->remote_bugs & BUG_SSH2_OLDGEX))
6903 hash_uint32(ssh->kex->hash, ssh->exhash, DH_MIN_SIZE);
6904 hash_uint32(ssh->kex->hash, ssh->exhash, s->pbits);
6905 if (!(ssh->remote_bugs & BUG_SSH2_OLDGEX))
6906 hash_uint32(ssh->kex->hash, ssh->exhash, DH_MAX_SIZE);
6907 hash_mpint(ssh->kex->hash, ssh->exhash, s->p);
6908 hash_mpint(ssh->kex->hash, ssh->exhash, s->g);
6910 hash_mpint(ssh->kex->hash, ssh->exhash, s->e);
6911 hash_mpint(ssh->kex->hash, ssh->exhash, s->f);
6913 dh_cleanup(ssh->kex_ctx);
6915 if (dh_is_gex(ssh->kex)) {
6919 } else if (ssh->kex->main_type == KEXTYPE_ECDH) {
6921 logeventf(ssh, "Doing ECDH key exchange with curve %s and hash %s",
6922 ssh_ecdhkex_curve_textname(ssh->kex),
6923 ssh->kex->hash->text_name);
6924 ssh->pkt_kctx = SSH2_PKTCTX_ECDHKEX;
6926 s->eckey = ssh_ecdhkex_newkey(ssh->kex);
6928 bombout(("Unable to generate key for ECDH"));
6934 int publicPointLength;
6935 publicPoint = ssh_ecdhkex_getpublic(s->eckey, &publicPointLength);
6937 ssh_ecdhkex_freekey(s->eckey);
6938 bombout(("Unable to encode public key for ECDH"));
6941 s->pktout = ssh2_pkt_init(SSH2_MSG_KEX_ECDH_INIT);
6942 ssh2_pkt_addstring_start(s->pktout);
6943 ssh2_pkt_addstring_data(s->pktout, publicPoint, publicPointLength);
6947 ssh2_pkt_send_noqueue(ssh, s->pktout);
6949 crWaitUntilV(pktin);
6950 if (pktin->type != SSH2_MSG_KEX_ECDH_REPLY) {
6951 ssh_ecdhkex_freekey(s->eckey);
6952 bombout(("expected ECDH reply packet from server"));
6956 ssh_pkt_getstring(pktin, &s->hostkeydata, &s->hostkeylen);
6957 if (!s->hostkeydata) {
6958 bombout(("unable to parse ECDH reply packet"));
6961 hash_string(ssh->kex->hash, ssh->exhash, s->hostkeydata, s->hostkeylen);
6962 s->hkey = ssh->hostkey->newkey(ssh->hostkey,
6963 s->hostkeydata, s->hostkeylen);
6967 int publicPointLength;
6968 publicPoint = ssh_ecdhkex_getpublic(s->eckey, &publicPointLength);
6970 ssh_ecdhkex_freekey(s->eckey);
6971 bombout(("Unable to encode public key for ECDH hash"));
6974 hash_string(ssh->kex->hash, ssh->exhash,
6975 publicPoint, publicPointLength);
6982 ssh_pkt_getstring(pktin, &keydata, &keylen);
6984 bombout(("unable to parse ECDH reply packet"));
6987 hash_string(ssh->kex->hash, ssh->exhash, keydata, keylen);
6988 s->K = ssh_ecdhkex_getkey(s->eckey, keydata, keylen);
6990 ssh_ecdhkex_freekey(s->eckey);
6991 bombout(("point received in ECDH was not valid"));
6996 ssh_pkt_getstring(pktin, &s->sigdata, &s->siglen);
6998 bombout(("unable to parse key exchange reply packet"));
7002 ssh_ecdhkex_freekey(s->eckey);
7004 logeventf(ssh, "Doing RSA key exchange with hash %s",
7005 ssh->kex->hash->text_name);
7006 ssh->pkt_kctx = SSH2_PKTCTX_RSAKEX;
7008 * RSA key exchange. First expect a KEXRSA_PUBKEY packet
7011 crWaitUntilV(pktin);
7012 if (pktin->type != SSH2_MSG_KEXRSA_PUBKEY) {
7013 bombout(("expected RSA public key packet from server"));
7017 ssh_pkt_getstring(pktin, &s->hostkeydata, &s->hostkeylen);
7018 if (!s->hostkeydata) {
7019 bombout(("unable to parse RSA public key packet"));
7022 hash_string(ssh->kex->hash, ssh->exhash,
7023 s->hostkeydata, s->hostkeylen);
7024 s->hkey = ssh->hostkey->newkey(ssh->hostkey,
7025 s->hostkeydata, s->hostkeylen);
7029 ssh_pkt_getstring(pktin, &keydata, &s->rsakeylen);
7031 bombout(("unable to parse RSA public key packet"));
7034 s->rsakeydata = snewn(s->rsakeylen, char);
7035 memcpy(s->rsakeydata, keydata, s->rsakeylen);
7038 s->rsakey = ssh_rsakex_newkey(s->rsakeydata, s->rsakeylen);
7040 sfree(s->rsakeydata);
7041 bombout(("unable to parse RSA public key from server"));
7045 hash_string(ssh->kex->hash, ssh->exhash, s->rsakeydata, s->rsakeylen);
7048 * Next, set up a shared secret K, of precisely KLEN -
7049 * 2*HLEN - 49 bits, where KLEN is the bit length of the
7050 * RSA key modulus and HLEN is the bit length of the hash
7054 int klen = ssh_rsakex_klen(s->rsakey);
7055 int nbits = klen - (2*ssh->kex->hash->hlen*8 + 49);
7057 unsigned char *kstr1, *kstr2, *outstr;
7058 int kstr1len, kstr2len, outstrlen;
7060 s->K = bn_power_2(nbits - 1);
7062 for (i = 0; i < nbits; i++) {
7064 byte = random_byte();
7066 bignum_set_bit(s->K, i, (byte >> (i & 7)) & 1);
7070 * Encode this as an mpint.
7072 kstr1 = ssh2_mpint_fmt(s->K, &kstr1len);
7073 kstr2 = snewn(kstr2len = 4 + kstr1len, unsigned char);
7074 PUT_32BIT(kstr2, kstr1len);
7075 memcpy(kstr2 + 4, kstr1, kstr1len);
7078 * Encrypt it with the given RSA key.
7080 outstrlen = (klen + 7) / 8;
7081 outstr = snewn(outstrlen, unsigned char);
7082 ssh_rsakex_encrypt(ssh->kex->hash, kstr2, kstr2len,
7083 outstr, outstrlen, s->rsakey);
7086 * And send it off in a return packet.
7088 s->pktout = ssh2_pkt_init(SSH2_MSG_KEXRSA_SECRET);
7089 ssh2_pkt_addstring_start(s->pktout);
7090 ssh2_pkt_addstring_data(s->pktout, (char *)outstr, outstrlen);
7091 ssh2_pkt_send_noqueue(ssh, s->pktout);
7093 hash_string(ssh->kex->hash, ssh->exhash, outstr, outstrlen);
7100 ssh_rsakex_freekey(s->rsakey);
7102 crWaitUntilV(pktin);
7103 if (pktin->type != SSH2_MSG_KEXRSA_DONE) {
7104 sfree(s->rsakeydata);
7105 bombout(("expected signature packet from server"));
7109 ssh_pkt_getstring(pktin, &s->sigdata, &s->siglen);
7111 bombout(("unable to parse signature packet"));
7115 sfree(s->rsakeydata);
7118 hash_mpint(ssh->kex->hash, ssh->exhash, s->K);
7119 assert(ssh->kex->hash->hlen <= sizeof(s->exchange_hash));
7120 ssh->kex->hash->final(ssh->exhash, s->exchange_hash);
7122 ssh->kex_ctx = NULL;
7125 debug(("Exchange hash is:\n"));
7126 dmemdump(s->exchange_hash, ssh->kex->hash->hlen);
7130 bombout(("Server's host key is invalid"));
7134 if (!ssh->hostkey->verifysig(s->hkey, s->sigdata, s->siglen,
7135 (char *)s->exchange_hash,
7136 ssh->kex->hash->hlen)) {
7138 bombout(("Server's host key did not match the signature supplied"));
7143 s->keystr = ssh->hostkey->fmtkey(s->hkey);
7144 if (!s->got_session_id) {
7146 * Authenticate remote host: verify host key. (We've already
7147 * checked the signature of the exchange hash.)
7149 s->fingerprint = ssh2_fingerprint(ssh->hostkey, s->hkey);
7150 logevent("Host key fingerprint is:");
7151 logevent(s->fingerprint);
7152 /* First check against manually configured host keys. */
7153 s->dlgret = verify_ssh_manual_host_key(ssh, s->fingerprint,
7154 ssh->hostkey, s->hkey);
7155 if (s->dlgret == 0) { /* did not match */
7156 bombout(("Host key did not appear in manually configured list"));
7158 } else if (s->dlgret < 0) { /* none configured; use standard handling */
7159 ssh_set_frozen(ssh, 1);
7160 s->dlgret = verify_ssh_host_key(ssh->frontend,
7161 ssh->savedhost, ssh->savedport,
7162 ssh->hostkey->keytype, s->keystr,
7164 ssh_dialog_callback, ssh);
7168 if (s->dlgret < 0) {
7172 bombout(("Unexpected data from server while waiting"
7173 " for user host key response"));
7176 } while (pktin || inlen > 0);
7177 s->dlgret = ssh->user_response;
7179 ssh_set_frozen(ssh, 0);
7180 if (s->dlgret == 0) {
7181 ssh_disconnect(ssh, "Aborted at host key verification", NULL,
7186 sfree(s->fingerprint);
7188 * Save this host key, to check against the one presented in
7189 * subsequent rekeys.
7191 ssh->hostkey_str = s->keystr;
7194 * In a rekey, we never present an interactive host key
7195 * verification request to the user. Instead, we simply
7196 * enforce that the key we're seeing this time is identical to
7197 * the one we saw before.
7199 if (strcmp(ssh->hostkey_str, s->keystr)) {
7201 bombout(("Host key was different in repeat key exchange"));
7207 ssh->hostkey->freekey(s->hkey);
7210 * The exchange hash from the very first key exchange is also
7211 * the session id, used in session key construction and
7214 if (!s->got_session_id) {
7215 assert(sizeof(s->exchange_hash) <= sizeof(ssh->v2_session_id));
7216 memcpy(ssh->v2_session_id, s->exchange_hash,
7217 sizeof(s->exchange_hash));
7218 ssh->v2_session_id_len = ssh->kex->hash->hlen;
7219 assert(ssh->v2_session_id_len <= sizeof(ssh->v2_session_id));
7220 s->got_session_id = TRUE;
7224 * Send SSH2_MSG_NEWKEYS.
7226 s->pktout = ssh2_pkt_init(SSH2_MSG_NEWKEYS);
7227 ssh2_pkt_send_noqueue(ssh, s->pktout);
7228 ssh->outgoing_data_size = 0; /* start counting from here */
7231 * We've sent client NEWKEYS, so create and initialise
7232 * client-to-server session keys.
7234 if (ssh->cs_cipher_ctx)
7235 ssh->cscipher->free_context(ssh->cs_cipher_ctx);
7236 ssh->cscipher = s->cscipher_tobe;
7237 if (ssh->cscipher) ssh->cs_cipher_ctx = ssh->cscipher->make_context();
7239 if (ssh->cs_mac_ctx)
7240 ssh->csmac->free_context(ssh->cs_mac_ctx);
7241 ssh->csmac = s->csmac_tobe;
7242 ssh->csmac_etm = s->csmac_etm_tobe;
7244 ssh->cs_mac_ctx = ssh->csmac->make_context(ssh->cs_cipher_ctx);
7246 if (ssh->cs_comp_ctx)
7247 ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
7248 ssh->cscomp = s->cscomp_tobe;
7249 ssh->cs_comp_ctx = ssh->cscomp->compress_init();
7252 * Set IVs on client-to-server keys. Here we use the exchange
7253 * hash from the _first_ key exchange.
7255 if (ssh->cscipher) {
7258 key = ssh2_mkkey(ssh, s->K, s->exchange_hash, 'C',
7259 ssh->cscipher->padded_keybytes);
7260 ssh->cscipher->setkey(ssh->cs_cipher_ctx, key);
7261 smemclr(key, ssh->cscipher->padded_keybytes);
7264 key = ssh2_mkkey(ssh, s->K, s->exchange_hash, 'A',
7265 ssh->cscipher->blksize);
7266 ssh->cscipher->setiv(ssh->cs_cipher_ctx, key);
7267 smemclr(key, ssh->cscipher->blksize);
7273 key = ssh2_mkkey(ssh, s->K, s->exchange_hash, 'E',
7274 ssh->csmac->keylen);
7275 ssh->csmac->setkey(ssh->cs_mac_ctx, key);
7276 smemclr(key, ssh->csmac->keylen);
7281 logeventf(ssh, "Initialised %.200s client->server encryption",
7282 ssh->cscipher->text_name);
7284 logeventf(ssh, "Initialised %.200s client->server MAC algorithm%s%s",
7285 ssh->csmac->text_name,
7286 ssh->csmac_etm ? " (in ETM mode)" : "",
7287 ssh->cscipher->required_mac ? " (required by cipher)" : "");
7288 if (ssh->cscomp->text_name)
7289 logeventf(ssh, "Initialised %s compression",
7290 ssh->cscomp->text_name);
7293 * Now our end of the key exchange is complete, we can send all
7294 * our queued higher-layer packets.
7296 ssh->queueing = FALSE;
7297 ssh2_pkt_queuesend(ssh);
7300 * Expect SSH2_MSG_NEWKEYS from server.
7302 crWaitUntilV(pktin);
7303 if (pktin->type != SSH2_MSG_NEWKEYS) {
7304 bombout(("expected new-keys packet from server"));
7307 ssh->incoming_data_size = 0; /* start counting from here */
7310 * We've seen server NEWKEYS, so create and initialise
7311 * server-to-client session keys.
7313 if (ssh->sc_cipher_ctx)
7314 ssh->sccipher->free_context(ssh->sc_cipher_ctx);
7315 if (ssh->sccipher) {
7316 ssh->sccipher = s->sccipher_tobe;
7317 ssh->sc_cipher_ctx = ssh->sccipher->make_context();
7320 if (ssh->sc_mac_ctx)
7321 ssh->scmac->free_context(ssh->sc_mac_ctx);
7323 ssh->scmac = s->scmac_tobe;
7324 ssh->scmac_etm = s->scmac_etm_tobe;
7325 ssh->sc_mac_ctx = ssh->scmac->make_context(ssh->sc_cipher_ctx);
7328 if (ssh->sc_comp_ctx)
7329 ssh->sccomp->decompress_cleanup(ssh->sc_comp_ctx);
7330 ssh->sccomp = s->sccomp_tobe;
7331 ssh->sc_comp_ctx = ssh->sccomp->decompress_init();
7334 * Set IVs on server-to-client keys. Here we use the exchange
7335 * hash from the _first_ key exchange.
7337 if (ssh->sccipher) {
7340 key = ssh2_mkkey(ssh, s->K, s->exchange_hash, 'D',
7341 ssh->sccipher->padded_keybytes);
7342 ssh->sccipher->setkey(ssh->sc_cipher_ctx, key);
7343 smemclr(key, ssh->sccipher->padded_keybytes);
7346 key = ssh2_mkkey(ssh, s->K, s->exchange_hash, 'B',
7347 ssh->sccipher->blksize);
7348 ssh->sccipher->setiv(ssh->sc_cipher_ctx, key);
7349 smemclr(key, ssh->sccipher->blksize);
7355 key = ssh2_mkkey(ssh, s->K, s->exchange_hash, 'F',
7356 ssh->scmac->keylen);
7357 ssh->scmac->setkey(ssh->sc_mac_ctx, key);
7358 smemclr(key, ssh->scmac->keylen);
7362 logeventf(ssh, "Initialised %.200s server->client encryption",
7363 ssh->sccipher->text_name);
7365 logeventf(ssh, "Initialised %.200s server->client MAC algorithm%s%s",
7366 ssh->scmac->text_name,
7367 ssh->scmac_etm ? " (in ETM mode)" : "",
7368 ssh->sccipher->required_mac ? " (required by cipher)" : "");
7369 if (ssh->sccomp->text_name)
7370 logeventf(ssh, "Initialised %s decompression",
7371 ssh->sccomp->text_name);
7374 * Free shared secret.
7379 * Key exchange is over. Loop straight back round if we have a
7380 * deferred rekey reason.
7382 if (ssh->deferred_rekey_reason) {
7383 logevent(ssh->deferred_rekey_reason);
7385 ssh->deferred_rekey_reason = NULL;
7386 goto begin_key_exchange;
7390 * Otherwise, schedule a timer for our next rekey.
7392 ssh->kex_in_progress = FALSE;
7393 ssh->last_rekey = GETTICKCOUNT();
7394 if (conf_get_int(ssh->conf, CONF_ssh_rekey_time) != 0)
7395 ssh->next_rekey = schedule_timer(conf_get_int(ssh->conf, CONF_ssh_rekey_time)*60*TICKSPERSEC,
7399 * Now we're encrypting. Begin returning 1 to the protocol main
7400 * function so that other things can run on top of the
7401 * transport. If we ever see a KEXINIT, we must go back to the
7404 * We _also_ go back to the start if we see pktin==NULL and
7405 * inlen negative, because this is a special signal meaning
7406 * `initiate client-driven rekey', and `in' contains a message
7407 * giving the reason for the rekey.
7409 * inlen==-1 means always initiate a rekey;
7410 * inlen==-2 means that userauth has completed successfully and
7411 * we should consider rekeying (for delayed compression).
7413 while (!((pktin && pktin->type == SSH2_MSG_KEXINIT) ||
7414 (!pktin && inlen < 0))) {
7416 if (!ssh->protocol_initial_phase_done) {
7417 ssh->protocol_initial_phase_done = TRUE;
7419 * Allow authconn to initialise itself.
7421 do_ssh2_authconn(ssh, NULL, 0, NULL);
7426 logevent("Server initiated key re-exchange");
7430 * authconn has seen a USERAUTH_SUCCEEDED. Time to enable
7431 * delayed compression, if it's available.
7433 * draft-miller-secsh-compression-delayed-00 says that you
7434 * negotiate delayed compression in the first key exchange, and
7435 * both sides start compressing when the server has sent
7436 * USERAUTH_SUCCESS. This has a race condition -- the server
7437 * can't know when the client has seen it, and thus which incoming
7438 * packets it should treat as compressed.
7440 * Instead, we do the initial key exchange without offering the
7441 * delayed methods, but note if the server offers them; when we
7442 * get here, if a delayed method was available that was higher
7443 * on our list than what we got, we initiate a rekey in which we
7444 * _do_ list the delayed methods (and hopefully get it as a
7445 * result). Subsequent rekeys will do the same.
7447 assert(!s->userauth_succeeded); /* should only happen once */
7448 s->userauth_succeeded = TRUE;
7449 if (!s->pending_compression)
7450 /* Can't see any point rekeying. */
7451 goto wait_for_rekey; /* this is utterly horrid */
7452 /* else fall through to rekey... */
7453 s->pending_compression = FALSE;
7456 * Now we've decided to rekey.
7458 * Special case: if the server bug is set that doesn't
7459 * allow rekeying, we give a different log message and
7460 * continue waiting. (If such a server _initiates_ a rekey,
7461 * we process it anyway!)
7463 if ((ssh->remote_bugs & BUG_SSH2_REKEY)) {
7464 logeventf(ssh, "Server bug prevents key re-exchange (%s)",
7466 /* Reset the counters, so that at least this message doesn't
7467 * hit the event log _too_ often. */
7468 ssh->outgoing_data_size = 0;
7469 ssh->incoming_data_size = 0;
7470 if (conf_get_int(ssh->conf, CONF_ssh_rekey_time) != 0) {
7472 schedule_timer(conf_get_int(ssh->conf, CONF_ssh_rekey_time)*60*TICKSPERSEC,
7475 goto wait_for_rekey; /* this is still utterly horrid */
7477 logeventf(ssh, "Initiating key re-exchange (%s)", (char *)in);
7480 goto begin_key_exchange;
7486 * Add data to an SSH-2 channel output buffer.
7488 static void ssh2_add_channel_data(struct ssh_channel *c, const char *buf,
7491 bufchain_add(&c->v.v2.outbuffer, buf, len);
7495 * Attempt to send data on an SSH-2 channel.
7497 static int ssh2_try_send(struct ssh_channel *c)
7500 struct Packet *pktout;
7503 while (c->v.v2.remwindow > 0 && bufchain_size(&c->v.v2.outbuffer) > 0) {
7506 bufchain_prefix(&c->v.v2.outbuffer, &data, &len);
7507 if ((unsigned)len > c->v.v2.remwindow)
7508 len = c->v.v2.remwindow;
7509 if ((unsigned)len > c->v.v2.remmaxpkt)
7510 len = c->v.v2.remmaxpkt;
7511 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_DATA);
7512 ssh2_pkt_adduint32(pktout, c->remoteid);
7513 ssh2_pkt_addstring_start(pktout);
7514 ssh2_pkt_addstring_data(pktout, data, len);
7515 ssh2_pkt_send(ssh, pktout);
7516 bufchain_consume(&c->v.v2.outbuffer, len);
7517 c->v.v2.remwindow -= len;
7521 * After having sent as much data as we can, return the amount
7524 ret = bufchain_size(&c->v.v2.outbuffer);
7527 * And if there's no data pending but we need to send an EOF, send
7530 if (!ret && c->pending_eof)
7531 ssh_channel_try_eof(c);
7536 static void ssh2_try_send_and_unthrottle(Ssh ssh, struct ssh_channel *c)
7539 if (c->closes & CLOSES_SENT_EOF)
7540 return; /* don't send on channels we've EOFed */
7541 bufsize = ssh2_try_send(c);
7544 case CHAN_MAINSESSION:
7545 /* stdin need not receive an unthrottle
7546 * notification since it will be polled */
7549 x11_unthrottle(c->u.x11.xconn);
7552 /* agent sockets are request/response and need no
7553 * buffer management */
7556 pfd_unthrottle(c->u.pfd.pf);
7562 static int ssh_is_simple(Ssh ssh)
7565 * We use the 'simple' variant of the SSH protocol if we're asked
7566 * to, except not if we're also doing connection-sharing (either
7567 * tunnelling our packets over an upstream or expecting to be
7568 * tunnelled over ourselves), since then the assumption that we
7569 * have only one channel to worry about is not true after all.
7571 return (conf_get_int(ssh->conf, CONF_ssh_simple) &&
7572 !ssh->bare_connection && !ssh->connshare);
7576 * Set up most of a new ssh_channel for SSH-2.
7578 static void ssh2_channel_init(struct ssh_channel *c)
7581 c->localid = alloc_channel_id(ssh);
7583 c->pending_eof = FALSE;
7584 c->throttling_conn = FALSE;
7585 c->v.v2.locwindow = c->v.v2.locmaxwin = c->v.v2.remlocwin =
7586 ssh_is_simple(ssh) ? OUR_V2_BIGWIN : OUR_V2_WINSIZE;
7587 c->v.v2.chanreq_head = NULL;
7588 c->v.v2.throttle_state = UNTHROTTLED;
7589 bufchain_init(&c->v.v2.outbuffer);
7593 * Construct the common parts of a CHANNEL_OPEN.
7595 static struct Packet *ssh2_chanopen_init(struct ssh_channel *c,
7598 struct Packet *pktout;
7600 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN);
7601 ssh2_pkt_addstring(pktout, type);
7602 ssh2_pkt_adduint32(pktout, c->localid);
7603 ssh2_pkt_adduint32(pktout, c->v.v2.locwindow);/* our window size */
7604 ssh2_pkt_adduint32(pktout, OUR_V2_MAXPKT); /* our max pkt size */
7609 * CHANNEL_FAILURE doesn't come with any indication of what message
7610 * caused it, so we have to keep track of the outstanding
7611 * CHANNEL_REQUESTs ourselves.
7613 static void ssh2_queue_chanreq_handler(struct ssh_channel *c,
7614 cchandler_fn_t handler, void *ctx)
7616 struct outstanding_channel_request *ocr =
7617 snew(struct outstanding_channel_request);
7619 assert(!(c->closes & (CLOSES_SENT_CLOSE | CLOSES_RCVD_CLOSE)));
7620 ocr->handler = handler;
7623 if (!c->v.v2.chanreq_head)
7624 c->v.v2.chanreq_head = ocr;
7626 c->v.v2.chanreq_tail->next = ocr;
7627 c->v.v2.chanreq_tail = ocr;
7631 * Construct the common parts of a CHANNEL_REQUEST. If handler is not
7632 * NULL then a reply will be requested and the handler will be called
7633 * when it arrives. The returned packet is ready to have any
7634 * request-specific data added and be sent. Note that if a handler is
7635 * provided, it's essential that the request actually be sent.
7637 * The handler will usually be passed the response packet in pktin. If
7638 * pktin is NULL, this means that no reply will ever be forthcoming
7639 * (e.g. because the entire connection is being destroyed, or because
7640 * the server initiated channel closure before we saw the response)
7641 * and the handler should free any storage it's holding.
7643 static struct Packet *ssh2_chanreq_init(struct ssh_channel *c,
7645 cchandler_fn_t handler, void *ctx)
7647 struct Packet *pktout;
7649 assert(!(c->closes & (CLOSES_SENT_CLOSE | CLOSES_RCVD_CLOSE)));
7650 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
7651 ssh2_pkt_adduint32(pktout, c->remoteid);
7652 ssh2_pkt_addstring(pktout, type);
7653 ssh2_pkt_addbool(pktout, handler != NULL);
7654 if (handler != NULL)
7655 ssh2_queue_chanreq_handler(c, handler, ctx);
7660 * Potentially enlarge the window on an SSH-2 channel.
7662 static void ssh2_handle_winadj_response(struct ssh_channel *, struct Packet *,
7664 static void ssh2_set_window(struct ssh_channel *c, int newwin)
7669 * Never send WINDOW_ADJUST for a channel that the remote side has
7670 * already sent EOF on; there's no point, since it won't be
7671 * sending any more data anyway. Ditto if _we've_ already sent
7674 if (c->closes & (CLOSES_RCVD_EOF | CLOSES_SENT_CLOSE))
7678 * Also, never widen the window for an X11 channel when we're
7679 * still waiting to see its initial auth and may yet hand it off
7682 if (c->type == CHAN_X11 && c->u.x11.initial)
7686 * If the remote end has a habit of ignoring maxpkt, limit the
7687 * window so that it has no choice (assuming it doesn't ignore the
7690 if ((ssh->remote_bugs & BUG_SSH2_MAXPKT) && newwin > OUR_V2_MAXPKT)
7691 newwin = OUR_V2_MAXPKT;
7694 * Only send a WINDOW_ADJUST if there's significantly more window
7695 * available than the other end thinks there is. This saves us
7696 * sending a WINDOW_ADJUST for every character in a shell session.
7698 * "Significant" is arbitrarily defined as half the window size.
7700 if (newwin / 2 >= c->v.v2.locwindow) {
7701 struct Packet *pktout;
7705 * In order to keep track of how much window the client
7706 * actually has available, we'd like it to acknowledge each
7707 * WINDOW_ADJUST. We can't do that directly, so we accompany
7708 * it with a CHANNEL_REQUEST that has to be acknowledged.
7710 * This is only necessary if we're opening the window wide.
7711 * If we're not, then throughput is being constrained by
7712 * something other than the maximum window size anyway.
7714 if (newwin == c->v.v2.locmaxwin &&
7715 !(ssh->remote_bugs & BUG_CHOKES_ON_WINADJ)) {
7716 up = snew(unsigned);
7717 *up = newwin - c->v.v2.locwindow;
7718 pktout = ssh2_chanreq_init(c, "winadj@putty.projects.tartarus.org",
7719 ssh2_handle_winadj_response, up);
7720 ssh2_pkt_send(ssh, pktout);
7722 if (c->v.v2.throttle_state != UNTHROTTLED)
7723 c->v.v2.throttle_state = UNTHROTTLING;
7725 /* Pretend the WINDOW_ADJUST was acked immediately. */
7726 c->v.v2.remlocwin = newwin;
7727 c->v.v2.throttle_state = THROTTLED;
7729 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
7730 ssh2_pkt_adduint32(pktout, c->remoteid);
7731 ssh2_pkt_adduint32(pktout, newwin - c->v.v2.locwindow);
7732 ssh2_pkt_send(ssh, pktout);
7733 c->v.v2.locwindow = newwin;
7738 * Find the channel associated with a message. If there's no channel,
7739 * or it's not properly open, make a noise about it and return NULL.
7741 static struct ssh_channel *ssh2_channel_msg(Ssh ssh, struct Packet *pktin)
7743 unsigned localid = ssh_pkt_getuint32(pktin);
7744 struct ssh_channel *c;
7746 c = find234(ssh->channels, &localid, ssh_channelfind);
7748 (c->type != CHAN_SHARING && c->halfopen &&
7749 pktin->type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION &&
7750 pktin->type != SSH2_MSG_CHANNEL_OPEN_FAILURE)) {
7751 char *buf = dupprintf("Received %s for %s channel %u",
7752 ssh2_pkt_type(ssh->pkt_kctx, ssh->pkt_actx,
7754 c ? "half-open" : "nonexistent", localid);
7755 ssh_disconnect(ssh, NULL, buf, SSH2_DISCONNECT_PROTOCOL_ERROR, FALSE);
7762 static void ssh2_handle_winadj_response(struct ssh_channel *c,
7763 struct Packet *pktin, void *ctx)
7765 unsigned *sizep = ctx;
7768 * Winadj responses should always be failures. However, at least
7769 * one server ("boks_sshd") is known to return SUCCESS for channel
7770 * requests it's never heard of, such as "winadj@putty". Raised
7771 * with foxt.com as bug 090916-090424, but for the sake of a quiet
7772 * life, we don't worry about what kind of response we got.
7775 c->v.v2.remlocwin += *sizep;
7778 * winadj messages are only sent when the window is fully open, so
7779 * if we get an ack of one, we know any pending unthrottle is
7782 if (c->v.v2.throttle_state == UNTHROTTLING)
7783 c->v.v2.throttle_state = UNTHROTTLED;
7786 static void ssh2_msg_channel_response(Ssh ssh, struct Packet *pktin)
7788 struct ssh_channel *c = ssh2_channel_msg(ssh, pktin);
7789 struct outstanding_channel_request *ocr;
7792 if (c->type == CHAN_SHARING) {
7793 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
7794 pktin->body, pktin->length);
7797 ocr = c->v.v2.chanreq_head;
7799 ssh2_msg_unexpected(ssh, pktin);
7802 ocr->handler(c, pktin, ocr->ctx);
7803 c->v.v2.chanreq_head = ocr->next;
7806 * We may now initiate channel-closing procedures, if that
7807 * CHANNEL_REQUEST was the last thing outstanding before we send
7810 ssh2_channel_check_close(c);
7813 static void ssh2_msg_channel_window_adjust(Ssh ssh, struct Packet *pktin)
7815 struct ssh_channel *c;
7816 c = ssh2_channel_msg(ssh, pktin);
7819 if (c->type == CHAN_SHARING) {
7820 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
7821 pktin->body, pktin->length);
7824 if (!(c->closes & CLOSES_SENT_EOF)) {
7825 c->v.v2.remwindow += ssh_pkt_getuint32(pktin);
7826 ssh2_try_send_and_unthrottle(ssh, c);
7830 static void ssh2_msg_channel_data(Ssh ssh, struct Packet *pktin)
7834 struct ssh_channel *c;
7835 c = ssh2_channel_msg(ssh, pktin);
7838 if (c->type == CHAN_SHARING) {
7839 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
7840 pktin->body, pktin->length);
7843 if (pktin->type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
7844 ssh_pkt_getuint32(pktin) != SSH2_EXTENDED_DATA_STDERR)
7845 return; /* extended but not stderr */
7846 ssh_pkt_getstring(pktin, &data, &length);
7849 c->v.v2.locwindow -= length;
7850 c->v.v2.remlocwin -= length;
7852 case CHAN_MAINSESSION:
7854 from_backend(ssh->frontend, pktin->type ==
7855 SSH2_MSG_CHANNEL_EXTENDED_DATA,
7859 bufsize = x11_send(c->u.x11.xconn, data, length);
7862 bufsize = pfd_send(c->u.pfd.pf, data, length);
7865 while (length > 0) {
7866 if (c->u.a.lensofar < 4) {
7867 unsigned int l = min(4 - c->u.a.lensofar,
7869 memcpy(c->u.a.msglen + c->u.a.lensofar,
7873 c->u.a.lensofar += l;
7875 if (c->u.a.lensofar == 4) {
7877 4 + GET_32BIT(c->u.a.msglen);
7878 c->u.a.message = snewn(c->u.a.totallen,
7880 memcpy(c->u.a.message, c->u.a.msglen, 4);
7882 if (c->u.a.lensofar >= 4 && length > 0) {
7884 min(c->u.a.totallen - c->u.a.lensofar,
7886 memcpy(c->u.a.message + c->u.a.lensofar,
7890 c->u.a.lensofar += l;
7892 if (c->u.a.lensofar == c->u.a.totallen) {
7895 c->u.a.outstanding_requests++;
7896 if (agent_query(c->u.a.message,
7899 ssh_agentf_callback, c))
7900 ssh_agentf_callback(c, reply, replylen);
7901 sfree(c->u.a.message);
7902 c->u.a.message = NULL;
7903 c->u.a.lensofar = 0;
7910 * If it looks like the remote end hit the end of its window,
7911 * and we didn't want it to do that, think about using a
7914 if (c->v.v2.remlocwin <= 0 && c->v.v2.throttle_state == UNTHROTTLED &&
7915 c->v.v2.locmaxwin < 0x40000000)
7916 c->v.v2.locmaxwin += OUR_V2_WINSIZE;
7918 * If we are not buffering too much data,
7919 * enlarge the window again at the remote side.
7920 * If we are buffering too much, we may still
7921 * need to adjust the window if the server's
7924 ssh2_set_window(c, bufsize < c->v.v2.locmaxwin ?
7925 c->v.v2.locmaxwin - bufsize : 0);
7927 * If we're either buffering way too much data, or if we're
7928 * buffering anything at all and we're in "simple" mode,
7929 * throttle the whole channel.
7931 if ((bufsize > c->v.v2.locmaxwin || (ssh_is_simple(ssh) && bufsize>0))
7932 && !c->throttling_conn) {
7933 c->throttling_conn = 1;
7934 ssh_throttle_conn(ssh, +1);
7939 static void ssh_check_termination(Ssh ssh)
7941 if (ssh->version == 2 &&
7942 !conf_get_int(ssh->conf, CONF_ssh_no_shell) &&
7943 (ssh->channels && count234(ssh->channels) == 0) &&
7944 !(ssh->connshare && share_ndownstreams(ssh->connshare) > 0)) {
7946 * We used to send SSH_MSG_DISCONNECT here, because I'd
7947 * believed that _every_ conforming SSH-2 connection had to
7948 * end with a disconnect being sent by at least one side;
7949 * apparently I was wrong and it's perfectly OK to
7950 * unceremoniously slam the connection shut when you're done,
7951 * and indeed OpenSSH feels this is more polite than sending a
7952 * DISCONNECT. So now we don't.
7954 ssh_disconnect(ssh, "All channels closed", NULL, 0, TRUE);
7958 void ssh_sharing_downstream_connected(Ssh ssh, unsigned id,
7959 const char *peerinfo)
7962 logeventf(ssh, "Connection sharing downstream #%u connected from %s",
7965 logeventf(ssh, "Connection sharing downstream #%u connected", id);
7968 void ssh_sharing_downstream_disconnected(Ssh ssh, unsigned id)
7970 logeventf(ssh, "Connection sharing downstream #%u disconnected", id);
7971 ssh_check_termination(ssh);
7974 void ssh_sharing_logf(Ssh ssh, unsigned id, const char *logfmt, ...)
7979 va_start(ap, logfmt);
7980 buf = dupvprintf(logfmt, ap);
7983 logeventf(ssh, "Connection sharing downstream #%u: %s", id, buf);
7985 logeventf(ssh, "Connection sharing: %s", buf);
7989 static void ssh_channel_destroy(struct ssh_channel *c)
7994 case CHAN_MAINSESSION:
7995 ssh->mainchan = NULL;
7996 update_specials_menu(ssh->frontend);
7999 if (c->u.x11.xconn != NULL)
8000 x11_close(c->u.x11.xconn);
8001 logevent("Forwarded X11 connection terminated");
8004 sfree(c->u.a.message);
8007 if (c->u.pfd.pf != NULL)
8008 pfd_close(c->u.pfd.pf);
8009 logevent("Forwarded port closed");
8013 del234(ssh->channels, c);
8014 if (ssh->version == 2) {
8015 bufchain_clear(&c->v.v2.outbuffer);
8016 assert(c->v.v2.chanreq_head == NULL);
8021 * If that was the last channel left open, we might need to
8024 ssh_check_termination(ssh);
8027 static void ssh2_channel_check_close(struct ssh_channel *c)
8030 struct Packet *pktout;
8034 * If we've sent out our own CHANNEL_OPEN but not yet seen
8035 * either OPEN_CONFIRMATION or OPEN_FAILURE in response, then
8036 * it's too early to be sending close messages of any kind.
8041 if ((!((CLOSES_SENT_EOF | CLOSES_RCVD_EOF) & ~c->closes) ||
8042 c->type == CHAN_ZOMBIE) &&
8043 !c->v.v2.chanreq_head &&
8044 !(c->closes & CLOSES_SENT_CLOSE)) {
8046 * We have both sent and received EOF (or the channel is a
8047 * zombie), and we have no outstanding channel requests, which
8048 * means the channel is in final wind-up. But we haven't sent
8049 * CLOSE, so let's do so now.
8051 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE);
8052 ssh2_pkt_adduint32(pktout, c->remoteid);
8053 ssh2_pkt_send(ssh, pktout);
8054 c->closes |= CLOSES_SENT_EOF | CLOSES_SENT_CLOSE;
8057 if (!((CLOSES_SENT_CLOSE | CLOSES_RCVD_CLOSE) & ~c->closes)) {
8058 assert(c->v.v2.chanreq_head == NULL);
8060 * We have both sent and received CLOSE, which means we're
8061 * completely done with the channel.
8063 ssh_channel_destroy(c);
8067 static void ssh2_channel_got_eof(struct ssh_channel *c)
8069 if (c->closes & CLOSES_RCVD_EOF)
8070 return; /* already seen EOF */
8071 c->closes |= CLOSES_RCVD_EOF;
8073 if (c->type == CHAN_X11) {
8074 x11_send_eof(c->u.x11.xconn);
8075 } else if (c->type == CHAN_AGENT) {
8076 if (c->u.a.outstanding_requests == 0) {
8077 /* Manufacture an outgoing EOF in response to the incoming one. */
8078 sshfwd_write_eof(c);
8080 } else if (c->type == CHAN_SOCKDATA) {
8081 pfd_send_eof(c->u.pfd.pf);
8082 } else if (c->type == CHAN_MAINSESSION) {
8085 if (!ssh->sent_console_eof &&
8086 (from_backend_eof(ssh->frontend) || ssh->got_pty)) {
8088 * Either from_backend_eof told us that the front end
8089 * wants us to close the outgoing side of the connection
8090 * as soon as we see EOF from the far end, or else we've
8091 * unilaterally decided to do that because we've allocated
8092 * a remote pty and hence EOF isn't a particularly
8093 * meaningful concept.
8095 sshfwd_write_eof(c);
8097 ssh->sent_console_eof = TRUE;
8100 ssh2_channel_check_close(c);
8103 static void ssh2_msg_channel_eof(Ssh ssh, struct Packet *pktin)
8105 struct ssh_channel *c;
8107 c = ssh2_channel_msg(ssh, pktin);
8110 if (c->type == CHAN_SHARING) {
8111 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
8112 pktin->body, pktin->length);
8115 ssh2_channel_got_eof(c);
8118 static void ssh2_msg_channel_close(Ssh ssh, struct Packet *pktin)
8120 struct ssh_channel *c;
8122 c = ssh2_channel_msg(ssh, pktin);
8125 if (c->type == CHAN_SHARING) {
8126 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
8127 pktin->body, pktin->length);
8132 * When we receive CLOSE on a channel, we assume it comes with an
8133 * implied EOF if we haven't seen EOF yet.
8135 ssh2_channel_got_eof(c);
8137 if (!(ssh->remote_bugs & BUG_SENDS_LATE_REQUEST_REPLY)) {
8139 * It also means we stop expecting to see replies to any
8140 * outstanding channel requests, so clean those up too.
8141 * (ssh_chanreq_init will enforce by assertion that we don't
8142 * subsequently put anything back on this list.)
8144 while (c->v.v2.chanreq_head) {
8145 struct outstanding_channel_request *ocr = c->v.v2.chanreq_head;
8146 ocr->handler(c, NULL, ocr->ctx);
8147 c->v.v2.chanreq_head = ocr->next;
8153 * And we also send an outgoing EOF, if we haven't already, on the
8154 * assumption that CLOSE is a pretty forceful announcement that
8155 * the remote side is doing away with the entire channel. (If it
8156 * had wanted to send us EOF and continue receiving data from us,
8157 * it would have just sent CHANNEL_EOF.)
8159 if (!(c->closes & CLOSES_SENT_EOF)) {
8161 * Make sure we don't read any more from whatever our local
8162 * data source is for this channel.
8165 case CHAN_MAINSESSION:
8166 ssh->send_ok = 0; /* stop trying to read from stdin */
8169 x11_override_throttle(c->u.x11.xconn, 1);
8172 pfd_override_throttle(c->u.pfd.pf, 1);
8177 * Abandon any buffered data we still wanted to send to this
8178 * channel. Receiving a CHANNEL_CLOSE is an indication that
8179 * the server really wants to get on and _destroy_ this
8180 * channel, and it isn't going to send us any further
8181 * WINDOW_ADJUSTs to permit us to send pending stuff.
8183 bufchain_clear(&c->v.v2.outbuffer);
8186 * Send outgoing EOF.
8188 sshfwd_write_eof(c);
8192 * Now process the actual close.
8194 if (!(c->closes & CLOSES_RCVD_CLOSE)) {
8195 c->closes |= CLOSES_RCVD_CLOSE;
8196 ssh2_channel_check_close(c);
8200 static void ssh2_msg_channel_open_confirmation(Ssh ssh, struct Packet *pktin)
8202 struct ssh_channel *c;
8204 c = ssh2_channel_msg(ssh, pktin);
8207 if (c->type == CHAN_SHARING) {
8208 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
8209 pktin->body, pktin->length);
8212 assert(c->halfopen); /* ssh2_channel_msg will have enforced this */
8213 c->remoteid = ssh_pkt_getuint32(pktin);
8214 c->halfopen = FALSE;
8215 c->v.v2.remwindow = ssh_pkt_getuint32(pktin);
8216 c->v.v2.remmaxpkt = ssh_pkt_getuint32(pktin);
8218 if (c->type == CHAN_SOCKDATA_DORMANT) {
8219 c->type = CHAN_SOCKDATA;
8221 pfd_confirm(c->u.pfd.pf);
8222 } else if (c->type == CHAN_ZOMBIE) {
8224 * This case can occur if a local socket error occurred
8225 * between us sending out CHANNEL_OPEN and receiving
8226 * OPEN_CONFIRMATION. In this case, all we can do is
8227 * immediately initiate close proceedings now that we know the
8228 * server's id to put in the close message.
8230 ssh2_channel_check_close(c);
8233 * We never expect to receive OPEN_CONFIRMATION for any
8234 * *other* channel type (since only local-to-remote port
8235 * forwardings cause us to send CHANNEL_OPEN after the main
8236 * channel is live - all other auxiliary channel types are
8237 * initiated from the server end). It's safe to enforce this
8238 * by assertion rather than by ssh_disconnect, because the
8239 * real point is that we never constructed a half-open channel
8240 * structure in the first place with any type other than the
8243 assert(!"Funny channel type in ssh2_msg_channel_open_confirmation");
8247 ssh_channel_try_eof(c); /* in case we had a pending EOF */
8250 static void ssh2_msg_channel_open_failure(Ssh ssh, struct Packet *pktin)
8252 static const char *const reasons[] = {
8253 "<unknown reason code>",
8254 "Administratively prohibited",
8256 "Unknown channel type",
8257 "Resource shortage",
8259 unsigned reason_code;
8260 char *reason_string;
8262 struct ssh_channel *c;
8264 c = ssh2_channel_msg(ssh, pktin);
8267 if (c->type == CHAN_SHARING) {
8268 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
8269 pktin->body, pktin->length);
8272 assert(c->halfopen); /* ssh2_channel_msg will have enforced this */
8274 if (c->type == CHAN_SOCKDATA_DORMANT) {
8275 reason_code = ssh_pkt_getuint32(pktin);
8276 if (reason_code >= lenof(reasons))
8277 reason_code = 0; /* ensure reasons[reason_code] in range */
8278 ssh_pkt_getstring(pktin, &reason_string, &reason_length);
8279 logeventf(ssh, "Forwarded connection refused by server: %s [%.*s]",
8280 reasons[reason_code], reason_length, reason_string);
8282 pfd_close(c->u.pfd.pf);
8283 } else if (c->type == CHAN_ZOMBIE) {
8285 * This case can occur if a local socket error occurred
8286 * between us sending out CHANNEL_OPEN and receiving
8287 * OPEN_FAILURE. In this case, we need do nothing except allow
8288 * the code below to throw the half-open channel away.
8292 * We never expect to receive OPEN_FAILURE for any *other*
8293 * channel type (since only local-to-remote port forwardings
8294 * cause us to send CHANNEL_OPEN after the main channel is
8295 * live - all other auxiliary channel types are initiated from
8296 * the server end). It's safe to enforce this by assertion
8297 * rather than by ssh_disconnect, because the real point is
8298 * that we never constructed a half-open channel structure in
8299 * the first place with any type other than the above.
8301 assert(!"Funny channel type in ssh2_msg_channel_open_failure");
8304 del234(ssh->channels, c);
8308 static void ssh2_msg_channel_request(Ssh ssh, struct Packet *pktin)
8311 int typelen, want_reply;
8312 int reply = SSH2_MSG_CHANNEL_FAILURE; /* default */
8313 struct ssh_channel *c;
8314 struct Packet *pktout;
8316 c = ssh2_channel_msg(ssh, pktin);
8319 if (c->type == CHAN_SHARING) {
8320 share_got_pkt_from_server(c->u.sharing.ctx, pktin->type,
8321 pktin->body, pktin->length);
8324 ssh_pkt_getstring(pktin, &type, &typelen);
8325 want_reply = ssh2_pkt_getbool(pktin);
8327 if (c->closes & CLOSES_SENT_CLOSE) {
8329 * We don't reply to channel requests after we've sent
8330 * CHANNEL_CLOSE for the channel, because our reply might
8331 * cross in the network with the other side's CHANNEL_CLOSE
8332 * and arrive after they have wound the channel up completely.
8338 * Having got the channel number, we now look at
8339 * the request type string to see if it's something
8342 if (c == ssh->mainchan) {
8344 * We recognise "exit-status" and "exit-signal" on
8345 * the primary channel.
8347 if (typelen == 11 &&
8348 !memcmp(type, "exit-status", 11)) {
8350 ssh->exitcode = ssh_pkt_getuint32(pktin);
8351 logeventf(ssh, "Server sent command exit status %d",
8353 reply = SSH2_MSG_CHANNEL_SUCCESS;
8355 } else if (typelen == 11 &&
8356 !memcmp(type, "exit-signal", 11)) {
8358 int is_plausible = TRUE, is_int = FALSE;
8359 char *fmt_sig = NULL, *fmt_msg = NULL;
8361 int msglen = 0, core = FALSE;
8362 /* ICK: older versions of OpenSSH (e.g. 3.4p1)
8363 * provide an `int' for the signal, despite its
8364 * having been a `string' in the drafts of RFC 4254 since at
8365 * least 2001. (Fixed in session.c 1.147.) Try to
8366 * infer which we can safely parse it as. */
8368 unsigned char *p = pktin->body +
8370 long len = pktin->length - pktin->savedpos;
8371 unsigned long num = GET_32BIT(p); /* what is it? */
8372 /* If it's 0, it hardly matters; assume string */
8376 int maybe_int = FALSE, maybe_str = FALSE;
8377 #define CHECK_HYPOTHESIS(offset, result) \
8380 int q = toint(offset); \
8381 if (q >= 0 && q+4 <= len) { \
8382 q = toint(q + 4 + GET_32BIT(p+q)); \
8383 if (q >= 0 && q+4 <= len && \
8384 ((q = toint(q + 4 + GET_32BIT(p+q))) != 0) && \
8389 CHECK_HYPOTHESIS(4+1, maybe_int);
8390 CHECK_HYPOTHESIS(4+num+1, maybe_str);
8391 #undef CHECK_HYPOTHESIS
8392 if (maybe_int && !maybe_str)
8394 else if (!maybe_int && maybe_str)
8397 /* Crikey. Either or neither. Panic. */
8398 is_plausible = FALSE;
8401 ssh->exitcode = 128; /* means `unknown signal' */
8404 /* Old non-standard OpenSSH. */
8405 int signum = ssh_pkt_getuint32(pktin);
8406 fmt_sig = dupprintf(" %d", signum);
8407 ssh->exitcode = 128 + signum;
8409 /* As per RFC 4254. */
8412 ssh_pkt_getstring(pktin, &sig, &siglen);
8413 /* Signal name isn't supposed to be blank, but
8414 * let's cope gracefully if it is. */
8416 fmt_sig = dupprintf(" \"%.*s\"",
8421 * Really hideous method of translating the
8422 * signal description back into a locally
8423 * meaningful number.
8428 #define TRANSLATE_SIGNAL(s) \
8429 else if (siglen == lenof(#s)-1 && !memcmp(sig, #s, siglen)) \
8430 ssh->exitcode = 128 + SIG ## s
8432 TRANSLATE_SIGNAL(ABRT);
8435 TRANSLATE_SIGNAL(ALRM);
8438 TRANSLATE_SIGNAL(FPE);
8441 TRANSLATE_SIGNAL(HUP);
8444 TRANSLATE_SIGNAL(ILL);
8447 TRANSLATE_SIGNAL(INT);
8450 TRANSLATE_SIGNAL(KILL);
8453 TRANSLATE_SIGNAL(PIPE);
8456 TRANSLATE_SIGNAL(QUIT);
8459 TRANSLATE_SIGNAL(SEGV);
8462 TRANSLATE_SIGNAL(TERM);
8465 TRANSLATE_SIGNAL(USR1);
8468 TRANSLATE_SIGNAL(USR2);
8470 #undef TRANSLATE_SIGNAL
8472 ssh->exitcode = 128;
8474 core = ssh2_pkt_getbool(pktin);
8475 ssh_pkt_getstring(pktin, &msg, &msglen);
8477 fmt_msg = dupprintf(" (\"%.*s\")", msglen, msg);
8479 /* ignore lang tag */
8480 } /* else don't attempt to parse */
8481 logeventf(ssh, "Server exited on signal%s%s%s",
8482 fmt_sig ? fmt_sig : "",
8483 core ? " (core dumped)" : "",
8484 fmt_msg ? fmt_msg : "");
8487 reply = SSH2_MSG_CHANNEL_SUCCESS;
8492 * This is a channel request we don't know
8493 * about, so we now either ignore the request
8494 * or respond with CHANNEL_FAILURE, depending
8497 reply = SSH2_MSG_CHANNEL_FAILURE;
8500 pktout = ssh2_pkt_init(reply);
8501 ssh2_pkt_adduint32(pktout, c->remoteid);
8502 ssh2_pkt_send(ssh, pktout);
8506 static void ssh2_msg_global_request(Ssh ssh, struct Packet *pktin)
8509 int typelen, want_reply;
8510 struct Packet *pktout;
8512 ssh_pkt_getstring(pktin, &type, &typelen);
8513 want_reply = ssh2_pkt_getbool(pktin);
8516 * We currently don't support any global requests
8517 * at all, so we either ignore the request or
8518 * respond with REQUEST_FAILURE, depending on
8522 pktout = ssh2_pkt_init(SSH2_MSG_REQUEST_FAILURE);
8523 ssh2_pkt_send(ssh, pktout);
8527 struct X11FakeAuth *ssh_sharing_add_x11_display(Ssh ssh, int authtype,
8531 struct X11FakeAuth *auth;
8534 * Make up a new set of fake X11 auth data, and add it to the tree
8535 * of currently valid ones with an indication of the sharing
8536 * context that it's relevant to.
8538 auth = x11_invent_fake_auth(ssh->x11authtree, authtype);
8539 auth->share_cs = share_cs;
8540 auth->share_chan = share_chan;
8545 void ssh_sharing_remove_x11_display(Ssh ssh, struct X11FakeAuth *auth)
8547 del234(ssh->x11authtree, auth);
8548 x11_free_fake_auth(auth);
8551 static void ssh2_msg_channel_open(Ssh ssh, struct Packet *pktin)
8558 const char *error = NULL;
8559 struct ssh_channel *c;
8560 unsigned remid, winsize, pktsize;
8561 unsigned our_winsize_override = 0;
8562 struct Packet *pktout;
8564 ssh_pkt_getstring(pktin, &type, &typelen);
8565 c = snew(struct ssh_channel);
8568 remid = ssh_pkt_getuint32(pktin);
8569 winsize = ssh_pkt_getuint32(pktin);
8570 pktsize = ssh_pkt_getuint32(pktin);
8572 if (typelen == 3 && !memcmp(type, "x11", 3)) {
8575 ssh_pkt_getstring(pktin, &peeraddr, &peeraddrlen);
8576 addrstr = snewn(peeraddrlen+1, char);
8577 memcpy(addrstr, peeraddr, peeraddrlen);
8578 addrstr[peeraddrlen] = '\0';
8579 peerport = ssh_pkt_getuint32(pktin);
8581 logeventf(ssh, "Received X11 connect request from %s:%d",
8584 if (!ssh->X11_fwd_enabled && !ssh->connshare)
8585 error = "X11 forwarding is not enabled";
8587 c->u.x11.xconn = x11_init(ssh->x11authtree, c,
8590 c->u.x11.initial = TRUE;
8593 * If we are a connection-sharing upstream, then we should
8594 * initially present a very small window, adequate to take
8595 * the X11 initial authorisation packet but not much more.
8596 * Downstream will then present us a larger window (by
8597 * fiat of the connection-sharing protocol) and we can
8598 * guarantee to send a positive-valued WINDOW_ADJUST.
8601 our_winsize_override = 128;
8603 logevent("Opened X11 forward channel");
8607 } else if (typelen == 15 &&
8608 !memcmp(type, "forwarded-tcpip", 15)) {
8609 struct ssh_rportfwd pf, *realpf;
8612 ssh_pkt_getstring(pktin, &shost, &shostlen);/* skip address */
8613 pf.shost = dupprintf("%.*s", shostlen, shost);
8614 pf.sport = ssh_pkt_getuint32(pktin);
8615 ssh_pkt_getstring(pktin, &peeraddr, &peeraddrlen);
8616 peerport = ssh_pkt_getuint32(pktin);
8617 realpf = find234(ssh->rportfwds, &pf, NULL);
8618 logeventf(ssh, "Received remote port %s:%d open request "
8619 "from %s:%d", pf.shost, pf.sport, peeraddr, peerport);
8622 if (realpf == NULL) {
8623 error = "Remote port is not recognised";
8627 if (realpf->share_ctx) {
8629 * This port forwarding is on behalf of a
8630 * connection-sharing downstream, so abandon our own
8631 * channel-open procedure and just pass the message on
8634 share_got_pkt_from_server(realpf->share_ctx, pktin->type,
8635 pktin->body, pktin->length);
8640 err = pfd_connect(&c->u.pfd.pf, realpf->dhost, realpf->dport,
8641 c, ssh->conf, realpf->pfrec->addressfamily);
8642 logeventf(ssh, "Attempting to forward remote port to "
8643 "%s:%d", realpf->dhost, realpf->dport);
8645 logeventf(ssh, "Port open failed: %s", err);
8647 error = "Port open failed";
8649 logevent("Forwarded port opened successfully");
8650 c->type = CHAN_SOCKDATA;
8653 } else if (typelen == 22 &&
8654 !memcmp(type, "auth-agent@openssh.com", 22)) {
8655 if (!ssh->agentfwd_enabled)
8656 error = "Agent forwarding is not enabled";
8658 c->type = CHAN_AGENT; /* identify channel type */
8659 c->u.a.lensofar = 0;
8660 c->u.a.message = NULL;
8661 c->u.a.outstanding_requests = 0;
8664 error = "Unsupported channel type requested";
8667 c->remoteid = remid;
8668 c->halfopen = FALSE;
8670 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_FAILURE);
8671 ssh2_pkt_adduint32(pktout, c->remoteid);
8672 ssh2_pkt_adduint32(pktout, SSH2_OPEN_CONNECT_FAILED);
8673 ssh2_pkt_addstring(pktout, error);
8674 ssh2_pkt_addstring(pktout, "en"); /* language tag */
8675 ssh2_pkt_send(ssh, pktout);
8676 logeventf(ssh, "Rejected channel open: %s", error);
8679 ssh2_channel_init(c);
8680 c->v.v2.remwindow = winsize;
8681 c->v.v2.remmaxpkt = pktsize;
8682 if (our_winsize_override) {
8683 c->v.v2.locwindow = c->v.v2.locmaxwin = c->v.v2.remlocwin =
8684 our_winsize_override;
8686 add234(ssh->channels, c);
8687 pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
8688 ssh2_pkt_adduint32(pktout, c->remoteid);
8689 ssh2_pkt_adduint32(pktout, c->localid);
8690 ssh2_pkt_adduint32(pktout, c->v.v2.locwindow);
8691 ssh2_pkt_adduint32(pktout, OUR_V2_MAXPKT); /* our max pkt size */
8692 ssh2_pkt_send(ssh, pktout);
8696 void sshfwd_x11_sharing_handover(struct ssh_channel *c,
8697 void *share_cs, void *share_chan,
8698 const char *peer_addr, int peer_port,
8699 int endian, int protomajor, int protominor,
8700 const void *initial_data, int initial_len)
8703 * This function is called when we've just discovered that an X
8704 * forwarding channel on which we'd been handling the initial auth
8705 * ourselves turns out to be destined for a connection-sharing
8706 * downstream. So we turn the channel into a CHAN_SHARING, meaning
8707 * that we completely stop tracking windows and buffering data and
8708 * just pass more or less unmodified SSH messages back and forth.
8710 c->type = CHAN_SHARING;
8711 c->u.sharing.ctx = share_cs;
8712 share_setup_x11_channel(share_cs, share_chan,
8713 c->localid, c->remoteid, c->v.v2.remwindow,
8714 c->v.v2.remmaxpkt, c->v.v2.locwindow,
8715 peer_addr, peer_port, endian,
8716 protomajor, protominor,
8717 initial_data, initial_len);
8720 void sshfwd_x11_is_local(struct ssh_channel *c)
8723 * This function is called when we've just discovered that an X
8724 * forwarding channel is _not_ destined for a connection-sharing
8725 * downstream but we're going to handle it ourselves. We stop
8726 * presenting a cautiously small window and go into ordinary data
8729 c->u.x11.initial = FALSE;
8730 ssh2_set_window(c, ssh_is_simple(c->ssh) ? OUR_V2_BIGWIN : OUR_V2_WINSIZE);
8734 * Buffer banner messages for later display at some convenient point,
8735 * if we're going to display them.
8737 static void ssh2_msg_userauth_banner(Ssh ssh, struct Packet *pktin)
8739 /* Arbitrary limit to prevent unbounded inflation of buffer */
8740 if (conf_get_int(ssh->conf, CONF_ssh_show_banner) &&
8741 bufchain_size(&ssh->banner) <= 131072) {
8742 char *banner = NULL;
8744 ssh_pkt_getstring(pktin, &banner, &size);
8746 bufchain_add(&ssh->banner, banner, size);
8750 /* Helper function to deal with sending tty modes for "pty-req" */
8751 static void ssh2_send_ttymode(void *data, char *mode, char *val)
8753 struct Packet *pktout = (struct Packet *)data;
8755 unsigned int arg = 0;
8756 while (strcmp(mode, ssh_ttymodes[i].mode) != 0) i++;
8757 if (i == lenof(ssh_ttymodes)) return;
8758 switch (ssh_ttymodes[i].type) {
8760 arg = ssh_tty_parse_specchar(val);
8763 arg = ssh_tty_parse_boolean(val);
8766 ssh2_pkt_addbyte(pktout, ssh_ttymodes[i].opcode);
8767 ssh2_pkt_adduint32(pktout, arg);
8770 static void ssh2_setup_x11(struct ssh_channel *c, struct Packet *pktin,
8773 struct ssh2_setup_x11_state {
8777 struct Packet *pktout;
8778 crStateP(ssh2_setup_x11_state, ctx);
8782 logevent("Requesting X11 forwarding");
8783 pktout = ssh2_chanreq_init(ssh->mainchan, "x11-req",
8785 ssh2_pkt_addbool(pktout, 0); /* many connections */
8786 ssh2_pkt_addstring(pktout, ssh->x11auth->protoname);
8787 ssh2_pkt_addstring(pktout, ssh->x11auth->datastring);
8788 ssh2_pkt_adduint32(pktout, ssh->x11disp->screennum);
8789 ssh2_pkt_send(ssh, pktout);
8791 /* Wait to be called back with either a response packet, or NULL
8792 * meaning clean up and free our data */
8796 if (pktin->type == SSH2_MSG_CHANNEL_SUCCESS) {
8797 logevent("X11 forwarding enabled");
8798 ssh->X11_fwd_enabled = TRUE;
8800 logevent("X11 forwarding refused");
8806 static void ssh2_setup_agent(struct ssh_channel *c, struct Packet *pktin,
8809 struct ssh2_setup_agent_state {
8813 struct Packet *pktout;
8814 crStateP(ssh2_setup_agent_state, ctx);
8818 logevent("Requesting OpenSSH-style agent forwarding");
8819 pktout = ssh2_chanreq_init(ssh->mainchan, "auth-agent-req@openssh.com",
8820 ssh2_setup_agent, s);
8821 ssh2_pkt_send(ssh, pktout);
8823 /* Wait to be called back with either a response packet, or NULL
8824 * meaning clean up and free our data */
8828 if (pktin->type == SSH2_MSG_CHANNEL_SUCCESS) {
8829 logevent("Agent forwarding enabled");
8830 ssh->agentfwd_enabled = TRUE;
8832 logevent("Agent forwarding refused");
8838 static void ssh2_setup_pty(struct ssh_channel *c, struct Packet *pktin,
8841 struct ssh2_setup_pty_state {
8845 struct Packet *pktout;
8846 crStateP(ssh2_setup_pty_state, ctx);
8850 /* Unpick the terminal-speed string. */
8851 /* XXX perhaps we should allow no speeds to be sent. */
8852 ssh->ospeed = 38400; ssh->ispeed = 38400; /* last-resort defaults */
8853 sscanf(conf_get_str(ssh->conf, CONF_termspeed), "%d,%d", &ssh->ospeed, &ssh->ispeed);
8854 /* Build the pty request. */
8855 pktout = ssh2_chanreq_init(ssh->mainchan, "pty-req",
8857 ssh2_pkt_addstring(pktout, conf_get_str(ssh->conf, CONF_termtype));
8858 ssh2_pkt_adduint32(pktout, ssh->term_width);
8859 ssh2_pkt_adduint32(pktout, ssh->term_height);
8860 ssh2_pkt_adduint32(pktout, 0); /* pixel width */
8861 ssh2_pkt_adduint32(pktout, 0); /* pixel height */
8862 ssh2_pkt_addstring_start(pktout);
8863 parse_ttymodes(ssh, ssh2_send_ttymode, (void *)pktout);
8864 ssh2_pkt_addbyte(pktout, SSH2_TTY_OP_ISPEED);
8865 ssh2_pkt_adduint32(pktout, ssh->ispeed);
8866 ssh2_pkt_addbyte(pktout, SSH2_TTY_OP_OSPEED);
8867 ssh2_pkt_adduint32(pktout, ssh->ospeed);
8868 ssh2_pkt_addstring_data(pktout, "\0", 1); /* TTY_OP_END */
8869 ssh2_pkt_send(ssh, pktout);
8870 ssh->state = SSH_STATE_INTERMED;
8872 /* Wait to be called back with either a response packet, or NULL
8873 * meaning clean up and free our data */
8877 if (pktin->type == SSH2_MSG_CHANNEL_SUCCESS) {
8878 logeventf(ssh, "Allocated pty (ospeed %dbps, ispeed %dbps)",
8879 ssh->ospeed, ssh->ispeed);
8880 ssh->got_pty = TRUE;
8882 c_write_str(ssh, "Server refused to allocate pty\r\n");
8883 ssh->editing = ssh->echoing = 1;
8890 static void ssh2_setup_env(struct ssh_channel *c, struct Packet *pktin,
8893 struct ssh2_setup_env_state {
8895 int num_env, env_left, env_ok;
8898 struct Packet *pktout;
8899 crStateP(ssh2_setup_env_state, ctx);
8904 * Send environment variables.
8906 * Simplest thing here is to send all the requests at once, and
8907 * then wait for a whole bunch of successes or failures.
8913 for (val = conf_get_str_strs(ssh->conf, CONF_environmt, NULL, &key);
8915 val = conf_get_str_strs(ssh->conf, CONF_environmt, key, &key)) {
8916 pktout = ssh2_chanreq_init(ssh->mainchan, "env", ssh2_setup_env, s);
8917 ssh2_pkt_addstring(pktout, key);
8918 ssh2_pkt_addstring(pktout, val);
8919 ssh2_pkt_send(ssh, pktout);
8924 logeventf(ssh, "Sent %d environment variables", s->num_env);
8929 s->env_left = s->num_env;
8931 while (s->env_left > 0) {
8932 /* Wait to be called back with either a response packet,
8933 * or NULL meaning clean up and free our data */
8935 if (!pktin) goto out;
8936 if (pktin->type == SSH2_MSG_CHANNEL_SUCCESS)
8941 if (s->env_ok == s->num_env) {
8942 logevent("All environment variables successfully set");
8943 } else if (s->env_ok == 0) {
8944 logevent("All environment variables refused");
8945 c_write_str(ssh, "Server refused to set environment variables\r\n");
8947 logeventf(ssh, "%d environment variables refused",
8948 s->num_env - s->env_ok);
8949 c_write_str(ssh, "Server refused to set all environment variables\r\n");
8957 * Handle the SSH-2 userauth and connection layers.
8959 static void ssh2_msg_authconn(Ssh ssh, struct Packet *pktin)
8961 do_ssh2_authconn(ssh, NULL, 0, pktin);
8964 static void ssh2_response_authconn(struct ssh_channel *c, struct Packet *pktin,
8968 do_ssh2_authconn(c->ssh, NULL, 0, pktin);
8971 static void do_ssh2_authconn(Ssh ssh, const unsigned char *in, int inlen,
8972 struct Packet *pktin)
8974 struct do_ssh2_authconn_state {
8978 AUTH_TYPE_PUBLICKEY,
8979 AUTH_TYPE_PUBLICKEY_OFFER_LOUD,
8980 AUTH_TYPE_PUBLICKEY_OFFER_QUIET,
8982 AUTH_TYPE_GSSAPI, /* always QUIET */
8983 AUTH_TYPE_KEYBOARD_INTERACTIVE,
8984 AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET
8986 int done_service_req;
8987 int gotit, need_pw, can_pubkey, can_passwd, can_keyb_inter;
8988 int tried_pubkey_config, done_agent;
8993 int kbd_inter_refused;
8994 int we_are_in, userauth_success;
8995 prompts_t *cur_prompt;
9000 void *publickey_blob;
9001 int publickey_bloblen;
9002 int privatekey_available, privatekey_encrypted;
9003 char *publickey_algorithm;
9004 char *publickey_comment;
9005 unsigned char agent_request[5], *agent_response, *agentp;
9006 int agent_responselen;
9007 unsigned char *pkblob_in_agent;
9009 char *pkblob, *alg, *commentp;
9010 int pklen, alglen, commentlen;
9011 int siglen, retlen, len;
9012 char *q, *agentreq, *ret;
9014 struct Packet *pktout;
9017 struct ssh_gss_library *gsslib;
9018 Ssh_gss_ctx gss_ctx;
9019 Ssh_gss_buf gss_buf;
9020 Ssh_gss_buf gss_rcvtok, gss_sndtok;
9021 Ssh_gss_name gss_srv_name;
9022 Ssh_gss_stat gss_stat;
9025 crState(do_ssh2_authconn_state);
9029 /* Register as a handler for all the messages this coroutine handles. */
9030 ssh->packet_dispatch[SSH2_MSG_SERVICE_ACCEPT] = ssh2_msg_authconn;
9031 ssh->packet_dispatch[SSH2_MSG_USERAUTH_REQUEST] = ssh2_msg_authconn;
9032 ssh->packet_dispatch[SSH2_MSG_USERAUTH_FAILURE] = ssh2_msg_authconn;
9033 ssh->packet_dispatch[SSH2_MSG_USERAUTH_SUCCESS] = ssh2_msg_authconn;
9034 ssh->packet_dispatch[SSH2_MSG_USERAUTH_BANNER] = ssh2_msg_authconn;
9035 ssh->packet_dispatch[SSH2_MSG_USERAUTH_PK_OK] = ssh2_msg_authconn;
9036 /* ssh->packet_dispatch[SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ] = ssh2_msg_authconn; duplicate case value */
9037 /* ssh->packet_dispatch[SSH2_MSG_USERAUTH_INFO_REQUEST] = ssh2_msg_authconn; duplicate case value */
9038 ssh->packet_dispatch[SSH2_MSG_USERAUTH_INFO_RESPONSE] = ssh2_msg_authconn;
9039 ssh->packet_dispatch[SSH2_MSG_GLOBAL_REQUEST] = ssh2_msg_authconn;
9040 ssh->packet_dispatch[SSH2_MSG_REQUEST_SUCCESS] = ssh2_msg_authconn;
9041 ssh->packet_dispatch[SSH2_MSG_REQUEST_FAILURE] = ssh2_msg_authconn;
9042 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN] = ssh2_msg_authconn;
9043 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_CONFIRMATION] = ssh2_msg_authconn;
9044 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_FAILURE] = ssh2_msg_authconn;
9045 ssh->packet_dispatch[SSH2_MSG_CHANNEL_WINDOW_ADJUST] = ssh2_msg_authconn;
9046 ssh->packet_dispatch[SSH2_MSG_CHANNEL_DATA] = ssh2_msg_authconn;
9047 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EXTENDED_DATA] = ssh2_msg_authconn;
9048 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EOF] = ssh2_msg_authconn;
9049 ssh->packet_dispatch[SSH2_MSG_CHANNEL_CLOSE] = ssh2_msg_authconn;
9051 s->done_service_req = FALSE;
9052 s->we_are_in = s->userauth_success = FALSE;
9053 s->agent_response = NULL;
9055 s->tried_gssapi = FALSE;
9058 if (!ssh->bare_connection) {
9059 if (!conf_get_int(ssh->conf, CONF_ssh_no_userauth)) {
9061 * Request userauth protocol, and await a response to it.
9063 s->pktout = ssh2_pkt_init(SSH2_MSG_SERVICE_REQUEST);
9064 ssh2_pkt_addstring(s->pktout, "ssh-userauth");
9065 ssh2_pkt_send(ssh, s->pktout);
9066 crWaitUntilV(pktin);
9067 if (pktin->type == SSH2_MSG_SERVICE_ACCEPT)
9068 s->done_service_req = TRUE;
9070 if (!s->done_service_req) {
9072 * Request connection protocol directly, without authentication.
9074 s->pktout = ssh2_pkt_init(SSH2_MSG_SERVICE_REQUEST);
9075 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9076 ssh2_pkt_send(ssh, s->pktout);
9077 crWaitUntilV(pktin);
9078 if (pktin->type == SSH2_MSG_SERVICE_ACCEPT) {
9079 s->we_are_in = TRUE; /* no auth required */
9081 bombout(("Server refused service request"));
9086 s->we_are_in = TRUE;
9089 /* Arrange to be able to deal with any BANNERs that come in.
9090 * (We do this now as packets may come in during the next bit.) */
9091 bufchain_init(&ssh->banner);
9092 ssh->packet_dispatch[SSH2_MSG_USERAUTH_BANNER] =
9093 ssh2_msg_userauth_banner;
9096 * Misc one-time setup for authentication.
9098 s->publickey_blob = NULL;
9099 if (!s->we_are_in) {
9102 * Load the public half of any configured public key file
9105 s->keyfile = conf_get_filename(ssh->conf, CONF_keyfile);
9106 if (!filename_is_null(s->keyfile)) {
9108 logeventf(ssh, "Reading key file \"%.150s\"",
9109 filename_to_str(s->keyfile));
9110 keytype = key_type(s->keyfile);
9111 if (keytype == SSH_KEYTYPE_SSH2 ||
9112 keytype == SSH_KEYTYPE_SSH2_PUBLIC_RFC4716 ||
9113 keytype == SSH_KEYTYPE_SSH2_PUBLIC_OPENSSH) {
9116 ssh2_userkey_loadpub(s->keyfile,
9117 &s->publickey_algorithm,
9118 &s->publickey_bloblen,
9119 &s->publickey_comment, &error);
9120 if (s->publickey_blob) {
9121 s->privatekey_available = (keytype == SSH_KEYTYPE_SSH2);
9122 if (!s->privatekey_available)
9123 logeventf(ssh, "Key file contains public key only");
9124 s->privatekey_encrypted =
9125 ssh2_userkey_encrypted(s->keyfile, NULL);
9128 logeventf(ssh, "Unable to load key (%s)",
9130 msgbuf = dupprintf("Unable to load key file "
9131 "\"%.150s\" (%s)\r\n",
9132 filename_to_str(s->keyfile),
9134 c_write_str(ssh, msgbuf);
9139 logeventf(ssh, "Unable to use this key file (%s)",
9140 key_type_to_str(keytype));
9141 msgbuf = dupprintf("Unable to use key file \"%.150s\""
9143 filename_to_str(s->keyfile),
9144 key_type_to_str(keytype));
9145 c_write_str(ssh, msgbuf);
9147 s->publickey_blob = NULL;
9152 * Find out about any keys Pageant has (but if there's a
9153 * public key configured, filter out all others).
9156 s->agent_response = NULL;
9157 s->pkblob_in_agent = NULL;
9158 if (conf_get_int(ssh->conf, CONF_tryagent) && agent_exists()) {
9162 logevent("Pageant is running. Requesting keys.");
9164 /* Request the keys held by the agent. */
9165 PUT_32BIT(s->agent_request, 1);
9166 s->agent_request[4] = SSH2_AGENTC_REQUEST_IDENTITIES;
9167 if (!agent_query(s->agent_request, 5, &r, &s->agent_responselen,
9168 ssh_agent_callback, ssh)) {
9172 bombout(("Unexpected data from server while"
9173 " waiting for agent response"));
9176 } while (pktin || inlen > 0);
9177 r = ssh->agent_response;
9178 s->agent_responselen = ssh->agent_response_len;
9180 s->agent_response = (unsigned char *) r;
9181 if (s->agent_response && s->agent_responselen >= 5 &&
9182 s->agent_response[4] == SSH2_AGENT_IDENTITIES_ANSWER) {
9185 p = s->agent_response + 5;
9186 s->nkeys = toint(GET_32BIT(p));
9189 * Vet the Pageant response to ensure that the key
9190 * count and blob lengths make sense.
9193 logeventf(ssh, "Pageant response contained a negative"
9194 " key count %d", s->nkeys);
9196 goto done_agent_query;
9198 unsigned char *q = p + 4;
9199 int lenleft = s->agent_responselen - 5 - 4;
9201 for (keyi = 0; keyi < s->nkeys; keyi++) {
9202 int bloblen, commentlen;
9204 logeventf(ssh, "Pageant response was truncated");
9206 goto done_agent_query;
9208 bloblen = toint(GET_32BIT(q));
9209 if (bloblen < 0 || bloblen > lenleft) {
9210 logeventf(ssh, "Pageant response was truncated");
9212 goto done_agent_query;
9214 lenleft -= 4 + bloblen;
9216 commentlen = toint(GET_32BIT(q));
9217 if (commentlen < 0 || commentlen > lenleft) {
9218 logeventf(ssh, "Pageant response was truncated");
9220 goto done_agent_query;
9222 lenleft -= 4 + commentlen;
9223 q += 4 + commentlen;
9228 logeventf(ssh, "Pageant has %d SSH-2 keys", s->nkeys);
9229 if (s->publickey_blob) {
9230 /* See if configured key is in agent. */
9231 for (keyi = 0; keyi < s->nkeys; keyi++) {
9232 s->pklen = toint(GET_32BIT(p));
9233 if (s->pklen == s->publickey_bloblen &&
9234 !memcmp(p+4, s->publickey_blob,
9235 s->publickey_bloblen)) {
9236 logeventf(ssh, "Pageant key #%d matches "
9237 "configured key file", keyi);
9239 s->pkblob_in_agent = p;
9243 p += toint(GET_32BIT(p)) + 4; /* comment */
9245 if (!s->pkblob_in_agent) {
9246 logevent("Configured key file not in Pageant");
9251 logevent("Failed to get reply from Pageant");
9259 * We repeat this whole loop, including the username prompt,
9260 * until we manage a successful authentication. If the user
9261 * types the wrong _password_, they can be sent back to the
9262 * beginning to try another username, if this is configured on.
9263 * (If they specify a username in the config, they are never
9264 * asked, even if they do give a wrong password.)
9266 * I think this best serves the needs of
9268 * - the people who have no configuration, no keys, and just
9269 * want to try repeated (username,password) pairs until they
9270 * type both correctly
9272 * - people who have keys and configuration but occasionally
9273 * need to fall back to passwords
9275 * - people with a key held in Pageant, who might not have
9276 * logged in to a particular machine before; so they want to
9277 * type a username, and then _either_ their key will be
9278 * accepted, _or_ they will type a password. If they mistype
9279 * the username they will want to be able to get back and
9282 s->got_username = FALSE;
9283 while (!s->we_are_in) {
9287 if (s->got_username && !conf_get_int(ssh->conf, CONF_change_username)) {
9289 * We got a username last time round this loop, and
9290 * with change_username turned off we don't try to get
9293 } else if ((ssh->username = get_remote_username(ssh->conf)) == NULL) {
9294 int ret; /* need not be kept over crReturn */
9295 s->cur_prompt = new_prompts(ssh->frontend);
9296 s->cur_prompt->to_server = TRUE;
9297 s->cur_prompt->name = dupstr("SSH login name");
9298 add_prompt(s->cur_prompt, dupstr("login as: "), TRUE);
9299 ret = get_userpass_input(s->cur_prompt, NULL, 0);
9302 crWaitUntilV(!pktin);
9303 ret = get_userpass_input(s->cur_prompt, in, inlen);
9308 * get_userpass_input() failed to get a username.
9311 free_prompts(s->cur_prompt);
9312 ssh_disconnect(ssh, "No username provided", NULL, 0, TRUE);
9315 ssh->username = dupstr(s->cur_prompt->prompts[0]->result);
9316 free_prompts(s->cur_prompt);
9319 if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
9320 stuff = dupprintf("Using username \"%s\".\r\n", ssh->username);
9321 c_write_str(ssh, stuff);
9325 s->got_username = TRUE;
9328 * Send an authentication request using method "none": (a)
9329 * just in case it succeeds, and (b) so that we know what
9330 * authentication methods we can usefully try next.
9332 ssh->pkt_actx = SSH2_PKTCTX_NOAUTH;
9334 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9335 ssh2_pkt_addstring(s->pktout, ssh->username);
9336 ssh2_pkt_addstring(s->pktout, "ssh-connection");/* service requested */
9337 ssh2_pkt_addstring(s->pktout, "none"); /* method */
9338 ssh2_pkt_send(ssh, s->pktout);
9339 s->type = AUTH_TYPE_NONE;
9341 s->we_are_in = FALSE;
9343 s->tried_pubkey_config = FALSE;
9344 s->kbd_inter_refused = FALSE;
9346 /* Reset agent request state. */
9347 s->done_agent = FALSE;
9348 if (s->agent_response) {
9349 if (s->pkblob_in_agent) {
9350 s->agentp = s->pkblob_in_agent;
9352 s->agentp = s->agent_response + 5 + 4;
9358 char *methods = NULL;
9362 * Wait for the result of the last authentication request.
9365 crWaitUntilV(pktin);
9367 * Now is a convenient point to spew any banner material
9368 * that we've accumulated. (This should ensure that when
9369 * we exit the auth loop, we haven't any left to deal
9373 int size = bufchain_size(&ssh->banner);
9375 * Don't show the banner if we're operating in
9376 * non-verbose non-interactive mode. (It's probably
9377 * a script, which means nobody will read the
9378 * banner _anyway_, and moreover the printing of
9379 * the banner will screw up processing on the
9380 * output of (say) plink.)
9382 if (size && (flags & (FLAG_VERBOSE | FLAG_INTERACTIVE))) {
9383 char *banner = snewn(size, char);
9384 bufchain_fetch(&ssh->banner, banner, size);
9385 c_write_untrusted(ssh, banner, size);
9388 bufchain_clear(&ssh->banner);
9390 if (pktin->type == SSH2_MSG_USERAUTH_SUCCESS) {
9391 logevent("Access granted");
9392 s->we_are_in = s->userauth_success = TRUE;
9396 if (pktin->type != SSH2_MSG_USERAUTH_FAILURE && s->type != AUTH_TYPE_GSSAPI) {
9397 bombout(("Strange packet received during authentication: "
9398 "type %d", pktin->type));
9405 * OK, we're now sitting on a USERAUTH_FAILURE message, so
9406 * we can look at the string in it and know what we can
9407 * helpfully try next.
9409 if (pktin->type == SSH2_MSG_USERAUTH_FAILURE) {
9410 ssh_pkt_getstring(pktin, &methods, &methlen);
9411 if (!ssh2_pkt_getbool(pktin)) {
9413 * We have received an unequivocal Access
9414 * Denied. This can translate to a variety of
9415 * messages, or no message at all.
9417 * For forms of authentication which are attempted
9418 * implicitly, by which I mean without printing
9419 * anything in the window indicating that we're
9420 * trying them, we should never print 'Access
9423 * If we do print a message saying that we're
9424 * attempting some kind of authentication, it's OK
9425 * to print a followup message saying it failed -
9426 * but the message may sometimes be more specific
9427 * than simply 'Access denied'.
9429 * Additionally, if we'd just tried password
9430 * authentication, we should break out of this
9431 * whole loop so as to go back to the username
9432 * prompt (iff we're configured to allow
9433 * username change attempts).
9435 if (s->type == AUTH_TYPE_NONE) {
9437 } else if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD ||
9438 s->type == AUTH_TYPE_PUBLICKEY_OFFER_QUIET) {
9439 if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD)
9440 c_write_str(ssh, "Server refused our key\r\n");
9441 logevent("Server refused our key");
9442 } else if (s->type == AUTH_TYPE_PUBLICKEY) {
9443 /* This _shouldn't_ happen except by a
9444 * protocol bug causing client and server to
9445 * disagree on what is a correct signature. */
9446 c_write_str(ssh, "Server refused public-key signature"
9447 " despite accepting key!\r\n");
9448 logevent("Server refused public-key signature"
9449 " despite accepting key!");
9450 } else if (s->type==AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET) {
9451 /* quiet, so no c_write */
9452 logevent("Server refused keyboard-interactive authentication");
9453 } else if (s->type==AUTH_TYPE_GSSAPI) {
9454 /* always quiet, so no c_write */
9455 /* also, the code down in the GSSAPI block has
9456 * already logged this in the Event Log */
9457 } else if (s->type == AUTH_TYPE_KEYBOARD_INTERACTIVE) {
9458 logevent("Keyboard-interactive authentication failed");
9459 c_write_str(ssh, "Access denied\r\n");
9461 assert(s->type == AUTH_TYPE_PASSWORD);
9462 logevent("Password authentication failed");
9463 c_write_str(ssh, "Access denied\r\n");
9465 if (conf_get_int(ssh->conf, CONF_change_username)) {
9466 /* XXX perhaps we should allow
9467 * keyboard-interactive to do this too? */
9468 s->we_are_in = FALSE;
9473 c_write_str(ssh, "Further authentication required\r\n");
9474 logevent("Further authentication required");
9478 in_commasep_string("publickey", methods, methlen);
9480 in_commasep_string("password", methods, methlen);
9481 s->can_keyb_inter = conf_get_int(ssh->conf, CONF_try_ki_auth) &&
9482 in_commasep_string("keyboard-interactive", methods, methlen);
9484 if (conf_get_int(ssh->conf, CONF_try_gssapi_auth) &&
9485 in_commasep_string("gssapi-with-mic", methods, methlen)) {
9486 /* Try loading the GSS libraries and see if we
9489 ssh->gsslibs = ssh_gss_setup(ssh->conf);
9490 s->can_gssapi = (ssh->gsslibs->nlibraries > 0);
9492 /* No point in even bothering to try to load the
9493 * GSS libraries, if the user configuration and
9494 * server aren't both prepared to attempt GSSAPI
9495 * auth in the first place. */
9496 s->can_gssapi = FALSE;
9501 ssh->pkt_actx = SSH2_PKTCTX_NOAUTH;
9503 if (s->can_pubkey && !s->done_agent && s->nkeys) {
9506 * Attempt public-key authentication using a key from Pageant.
9509 ssh->pkt_actx = SSH2_PKTCTX_PUBLICKEY;
9511 logeventf(ssh, "Trying Pageant key #%d", s->keyi);
9513 /* Unpack key from agent response */
9514 s->pklen = toint(GET_32BIT(s->agentp));
9516 s->pkblob = (char *)s->agentp;
9517 s->agentp += s->pklen;
9518 s->alglen = toint(GET_32BIT(s->pkblob));
9519 s->alg = s->pkblob + 4;
9520 s->commentlen = toint(GET_32BIT(s->agentp));
9522 s->commentp = (char *)s->agentp;
9523 s->agentp += s->commentlen;
9524 /* s->agentp now points at next key, if any */
9526 /* See if server will accept it */
9527 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9528 ssh2_pkt_addstring(s->pktout, ssh->username);
9529 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9530 /* service requested */
9531 ssh2_pkt_addstring(s->pktout, "publickey");
9533 ssh2_pkt_addbool(s->pktout, FALSE); /* no signature included */
9534 ssh2_pkt_addstring_start(s->pktout);
9535 ssh2_pkt_addstring_data(s->pktout, s->alg, s->alglen);
9536 ssh2_pkt_addstring_start(s->pktout);
9537 ssh2_pkt_addstring_data(s->pktout, s->pkblob, s->pklen);
9538 ssh2_pkt_send(ssh, s->pktout);
9539 s->type = AUTH_TYPE_PUBLICKEY_OFFER_QUIET;
9541 crWaitUntilV(pktin);
9542 if (pktin->type != SSH2_MSG_USERAUTH_PK_OK) {
9544 /* Offer of key refused. */
9551 if (flags & FLAG_VERBOSE) {
9552 c_write_str(ssh, "Authenticating with "
9554 c_write(ssh, s->commentp, s->commentlen);
9555 c_write_str(ssh, "\" from agent\r\n");
9559 * Server is willing to accept the key.
9560 * Construct a SIGN_REQUEST.
9562 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9563 ssh2_pkt_addstring(s->pktout, ssh->username);
9564 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9565 /* service requested */
9566 ssh2_pkt_addstring(s->pktout, "publickey");
9568 ssh2_pkt_addbool(s->pktout, TRUE); /* signature included */
9569 ssh2_pkt_addstring_start(s->pktout);
9570 ssh2_pkt_addstring_data(s->pktout, s->alg, s->alglen);
9571 ssh2_pkt_addstring_start(s->pktout);
9572 ssh2_pkt_addstring_data(s->pktout, s->pkblob, s->pklen);
9574 /* Ask agent for signature. */
9575 s->siglen = s->pktout->length - 5 + 4 +
9576 ssh->v2_session_id_len;
9577 if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
9579 s->len = 1; /* message type */
9580 s->len += 4 + s->pklen; /* key blob */
9581 s->len += 4 + s->siglen; /* data to sign */
9582 s->len += 4; /* flags */
9583 s->agentreq = snewn(4 + s->len, char);
9584 PUT_32BIT(s->agentreq, s->len);
9585 s->q = s->agentreq + 4;
9586 *s->q++ = SSH2_AGENTC_SIGN_REQUEST;
9587 PUT_32BIT(s->q, s->pklen);
9589 memcpy(s->q, s->pkblob, s->pklen);
9591 PUT_32BIT(s->q, s->siglen);
9593 /* Now the data to be signed... */
9594 if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
9595 PUT_32BIT(s->q, ssh->v2_session_id_len);
9598 memcpy(s->q, ssh->v2_session_id,
9599 ssh->v2_session_id_len);
9600 s->q += ssh->v2_session_id_len;
9601 memcpy(s->q, s->pktout->data + 5,
9602 s->pktout->length - 5);
9603 s->q += s->pktout->length - 5;
9604 /* And finally the (zero) flags word. */
9606 if (!agent_query(s->agentreq, s->len + 4,
9608 ssh_agent_callback, ssh)) {
9612 bombout(("Unexpected data from server"
9613 " while waiting for agent"
9617 } while (pktin || inlen > 0);
9618 vret = ssh->agent_response;
9619 s->retlen = ssh->agent_response_len;
9624 if (s->retlen >= 9 &&
9625 s->ret[4] == SSH2_AGENT_SIGN_RESPONSE &&
9626 GET_32BIT(s->ret + 5) <= (unsigned)(s->retlen-9)) {
9627 logevent("Sending Pageant's response");
9628 ssh2_add_sigblob(ssh, s->pktout,
9629 s->pkblob, s->pklen,
9631 GET_32BIT(s->ret + 5));
9632 ssh2_pkt_send(ssh, s->pktout);
9633 s->type = AUTH_TYPE_PUBLICKEY;
9635 /* FIXME: less drastic response */
9636 bombout(("Pageant failed to answer challenge"));
9642 /* Do we have any keys left to try? */
9643 if (s->pkblob_in_agent) {
9644 s->done_agent = TRUE;
9645 s->tried_pubkey_config = TRUE;
9648 if (s->keyi >= s->nkeys)
9649 s->done_agent = TRUE;
9652 } else if (s->can_pubkey && s->publickey_blob &&
9653 s->privatekey_available && !s->tried_pubkey_config) {
9655 struct ssh2_userkey *key; /* not live over crReturn */
9656 char *passphrase; /* not live over crReturn */
9658 ssh->pkt_actx = SSH2_PKTCTX_PUBLICKEY;
9660 s->tried_pubkey_config = TRUE;
9663 * Try the public key supplied in the configuration.
9665 * First, offer the public blob to see if the server is
9666 * willing to accept it.
9668 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9669 ssh2_pkt_addstring(s->pktout, ssh->username);
9670 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9671 /* service requested */
9672 ssh2_pkt_addstring(s->pktout, "publickey"); /* method */
9673 ssh2_pkt_addbool(s->pktout, FALSE);
9674 /* no signature included */
9675 ssh2_pkt_addstring(s->pktout, s->publickey_algorithm);
9676 ssh2_pkt_addstring_start(s->pktout);
9677 ssh2_pkt_addstring_data(s->pktout,
9678 (char *)s->publickey_blob,
9679 s->publickey_bloblen);
9680 ssh2_pkt_send(ssh, s->pktout);
9681 logevent("Offered public key");
9683 crWaitUntilV(pktin);
9684 if (pktin->type != SSH2_MSG_USERAUTH_PK_OK) {
9685 /* Key refused. Give up. */
9686 s->gotit = TRUE; /* reconsider message next loop */
9687 s->type = AUTH_TYPE_PUBLICKEY_OFFER_LOUD;
9688 continue; /* process this new message */
9690 logevent("Offer of public key accepted");
9693 * Actually attempt a serious authentication using
9696 if (flags & FLAG_VERBOSE) {
9697 c_write_str(ssh, "Authenticating with public key \"");
9698 c_write_str(ssh, s->publickey_comment);
9699 c_write_str(ssh, "\"\r\n");
9703 const char *error; /* not live over crReturn */
9704 if (s->privatekey_encrypted) {
9706 * Get a passphrase from the user.
9708 int ret; /* need not be kept over crReturn */
9709 s->cur_prompt = new_prompts(ssh->frontend);
9710 s->cur_prompt->to_server = FALSE;
9711 s->cur_prompt->name = dupstr("SSH key passphrase");
9712 add_prompt(s->cur_prompt,
9713 dupprintf("Passphrase for key \"%.100s\": ",
9714 s->publickey_comment),
9716 ret = get_userpass_input(s->cur_prompt, NULL, 0);
9719 crWaitUntilV(!pktin);
9720 ret = get_userpass_input(s->cur_prompt,
9725 /* Failed to get a passphrase. Terminate. */
9726 free_prompts(s->cur_prompt);
9727 ssh_disconnect(ssh, NULL,
9728 "Unable to authenticate",
9729 SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER,
9734 dupstr(s->cur_prompt->prompts[0]->result);
9735 free_prompts(s->cur_prompt);
9737 passphrase = NULL; /* no passphrase needed */
9741 * Try decrypting the key.
9743 s->keyfile = conf_get_filename(ssh->conf, CONF_keyfile);
9744 key = ssh2_load_userkey(s->keyfile, passphrase, &error);
9746 /* burn the evidence */
9747 smemclr(passphrase, strlen(passphrase));
9750 if (key == SSH2_WRONG_PASSPHRASE || key == NULL) {
9752 (key == SSH2_WRONG_PASSPHRASE)) {
9753 c_write_str(ssh, "Wrong passphrase\r\n");
9755 /* and loop again */
9757 c_write_str(ssh, "Unable to load private key (");
9758 c_write_str(ssh, error);
9759 c_write_str(ssh, ")\r\n");
9761 break; /* try something else */
9767 unsigned char *pkblob, *sigblob, *sigdata;
9768 int pkblob_len, sigblob_len, sigdata_len;
9772 * We have loaded the private key and the server
9773 * has announced that it's willing to accept it.
9774 * Hallelujah. Generate a signature and send it.
9776 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9777 ssh2_pkt_addstring(s->pktout, ssh->username);
9778 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9779 /* service requested */
9780 ssh2_pkt_addstring(s->pktout, "publickey");
9782 ssh2_pkt_addbool(s->pktout, TRUE);
9783 /* signature follows */
9784 ssh2_pkt_addstring(s->pktout, key->alg->name);
9785 pkblob = key->alg->public_blob(key->data,
9787 ssh2_pkt_addstring_start(s->pktout);
9788 ssh2_pkt_addstring_data(s->pktout, (char *)pkblob,
9792 * The data to be signed is:
9796 * followed by everything so far placed in the
9799 sigdata_len = s->pktout->length - 5 + 4 +
9800 ssh->v2_session_id_len;
9801 if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
9803 sigdata = snewn(sigdata_len, unsigned char);
9805 if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
9806 PUT_32BIT(sigdata+p, ssh->v2_session_id_len);
9809 memcpy(sigdata+p, ssh->v2_session_id,
9810 ssh->v2_session_id_len);
9811 p += ssh->v2_session_id_len;
9812 memcpy(sigdata+p, s->pktout->data + 5,
9813 s->pktout->length - 5);
9814 p += s->pktout->length - 5;
9815 assert(p == sigdata_len);
9816 sigblob = key->alg->sign(key->data, (char *)sigdata,
9817 sigdata_len, &sigblob_len);
9818 ssh2_add_sigblob(ssh, s->pktout, pkblob, pkblob_len,
9819 sigblob, sigblob_len);
9824 ssh2_pkt_send(ssh, s->pktout);
9825 logevent("Sent public key signature");
9826 s->type = AUTH_TYPE_PUBLICKEY;
9827 key->alg->freekey(key->data);
9828 sfree(key->comment);
9833 } else if (s->can_gssapi && !s->tried_gssapi) {
9835 /* GSSAPI Authentication */
9840 s->type = AUTH_TYPE_GSSAPI;
9841 s->tried_gssapi = TRUE;
9843 ssh->pkt_actx = SSH2_PKTCTX_GSSAPI;
9846 * Pick the highest GSS library on the preference
9852 for (i = 0; i < ngsslibs; i++) {
9853 int want_id = conf_get_int_int(ssh->conf,
9854 CONF_ssh_gsslist, i);
9855 for (j = 0; j < ssh->gsslibs->nlibraries; j++)
9856 if (ssh->gsslibs->libraries[j].id == want_id) {
9857 s->gsslib = &ssh->gsslibs->libraries[j];
9858 goto got_gsslib; /* double break */
9863 * We always expect to have found something in
9864 * the above loop: we only came here if there
9865 * was at least one viable GSS library, and the
9866 * preference list should always mention
9867 * everything and only change the order.
9872 if (s->gsslib->gsslogmsg)
9873 logevent(s->gsslib->gsslogmsg);
9875 /* Sending USERAUTH_REQUEST with "gssapi-with-mic" method */
9876 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
9877 ssh2_pkt_addstring(s->pktout, ssh->username);
9878 ssh2_pkt_addstring(s->pktout, "ssh-connection");
9879 ssh2_pkt_addstring(s->pktout, "gssapi-with-mic");
9880 logevent("Attempting GSSAPI authentication");
9882 /* add mechanism info */
9883 s->gsslib->indicate_mech(s->gsslib, &s->gss_buf);
9885 /* number of GSSAPI mechanisms */
9886 ssh2_pkt_adduint32(s->pktout,1);
9888 /* length of OID + 2 */
9889 ssh2_pkt_adduint32(s->pktout, s->gss_buf.length + 2);
9890 ssh2_pkt_addbyte(s->pktout, SSH2_GSS_OIDTYPE);
9893 ssh2_pkt_addbyte(s->pktout, (unsigned char) s->gss_buf.length);
9895 ssh_pkt_adddata(s->pktout, s->gss_buf.value,
9897 ssh2_pkt_send(ssh, s->pktout);
9898 crWaitUntilV(pktin);
9899 if (pktin->type != SSH2_MSG_USERAUTH_GSSAPI_RESPONSE) {
9900 logevent("GSSAPI authentication request refused");
9904 /* check returned packet ... */
9906 ssh_pkt_getstring(pktin, &data, &len);
9907 s->gss_rcvtok.value = data;
9908 s->gss_rcvtok.length = len;
9909 if (s->gss_rcvtok.length != s->gss_buf.length + 2 ||
9910 ((char *)s->gss_rcvtok.value)[0] != SSH2_GSS_OIDTYPE ||
9911 ((char *)s->gss_rcvtok.value)[1] != s->gss_buf.length ||
9912 memcmp((char *)s->gss_rcvtok.value + 2,
9913 s->gss_buf.value,s->gss_buf.length) ) {
9914 logevent("GSSAPI authentication - wrong response from server");
9918 /* now start running */
9919 s->gss_stat = s->gsslib->import_name(s->gsslib,
9922 if (s->gss_stat != SSH_GSS_OK) {
9923 if (s->gss_stat == SSH_GSS_BAD_HOST_NAME)
9924 logevent("GSSAPI import name failed - Bad service name");
9926 logevent("GSSAPI import name failed");
9930 /* fetch TGT into GSS engine */
9931 s->gss_stat = s->gsslib->acquire_cred(s->gsslib, &s->gss_ctx);
9933 if (s->gss_stat != SSH_GSS_OK) {
9934 logevent("GSSAPI authentication failed to get credentials");
9935 s->gsslib->release_name(s->gsslib, &s->gss_srv_name);
9939 /* initial tokens are empty */
9940 SSH_GSS_CLEAR_BUF(&s->gss_rcvtok);
9941 SSH_GSS_CLEAR_BUF(&s->gss_sndtok);
9943 /* now enter the loop */
9945 s->gss_stat = s->gsslib->init_sec_context
9949 conf_get_int(ssh->conf, CONF_gssapifwd),
9953 if (s->gss_stat!=SSH_GSS_S_COMPLETE &&
9954 s->gss_stat!=SSH_GSS_S_CONTINUE_NEEDED) {
9955 logevent("GSSAPI authentication initialisation failed");
9957 if (s->gsslib->display_status(s->gsslib, s->gss_ctx,
9958 &s->gss_buf) == SSH_GSS_OK) {
9959 logevent(s->gss_buf.value);
9960 sfree(s->gss_buf.value);
9965 logevent("GSSAPI authentication initialised");
9967 /* Client and server now exchange tokens until GSSAPI
9968 * no longer says CONTINUE_NEEDED */
9970 if (s->gss_sndtok.length != 0) {
9971 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
9972 ssh_pkt_addstring_start(s->pktout);
9973 ssh_pkt_addstring_data(s->pktout,s->gss_sndtok.value,s->gss_sndtok.length);
9974 ssh2_pkt_send(ssh, s->pktout);
9975 s->gsslib->free_tok(s->gsslib, &s->gss_sndtok);
9978 if (s->gss_stat == SSH_GSS_S_CONTINUE_NEEDED) {
9979 crWaitUntilV(pktin);
9980 if (pktin->type != SSH2_MSG_USERAUTH_GSSAPI_TOKEN) {
9981 logevent("GSSAPI authentication - bad server response");
9982 s->gss_stat = SSH_GSS_FAILURE;
9985 ssh_pkt_getstring(pktin, &data, &len);
9986 s->gss_rcvtok.value = data;
9987 s->gss_rcvtok.length = len;
9989 } while (s-> gss_stat == SSH_GSS_S_CONTINUE_NEEDED);
9991 if (s->gss_stat != SSH_GSS_OK) {
9992 s->gsslib->release_name(s->gsslib, &s->gss_srv_name);
9993 s->gsslib->release_cred(s->gsslib, &s->gss_ctx);
9996 logevent("GSSAPI authentication loop finished OK");
9998 /* Now send the MIC */
10000 s->pktout = ssh2_pkt_init(0);
10001 micoffset = s->pktout->length;
10002 ssh_pkt_addstring_start(s->pktout);
10003 ssh_pkt_addstring_data(s->pktout, (char *)ssh->v2_session_id, ssh->v2_session_id_len);
10004 ssh_pkt_addbyte(s->pktout, SSH2_MSG_USERAUTH_REQUEST);
10005 ssh_pkt_addstring(s->pktout, ssh->username);
10006 ssh_pkt_addstring(s->pktout, "ssh-connection");
10007 ssh_pkt_addstring(s->pktout, "gssapi-with-mic");
10009 s->gss_buf.value = (char *)s->pktout->data + micoffset;
10010 s->gss_buf.length = s->pktout->length - micoffset;
10012 s->gsslib->get_mic(s->gsslib, s->gss_ctx, &s->gss_buf, &mic);
10013 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_GSSAPI_MIC);
10014 ssh_pkt_addstring_start(s->pktout);
10015 ssh_pkt_addstring_data(s->pktout, mic.value, mic.length);
10016 ssh2_pkt_send(ssh, s->pktout);
10017 s->gsslib->free_mic(s->gsslib, &mic);
10021 s->gsslib->release_name(s->gsslib, &s->gss_srv_name);
10022 s->gsslib->release_cred(s->gsslib, &s->gss_ctx);
10025 } else if (s->can_keyb_inter && !s->kbd_inter_refused) {
10028 * Keyboard-interactive authentication.
10031 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
10033 ssh->pkt_actx = SSH2_PKTCTX_KBDINTER;
10035 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
10036 ssh2_pkt_addstring(s->pktout, ssh->username);
10037 ssh2_pkt_addstring(s->pktout, "ssh-connection");
10038 /* service requested */
10039 ssh2_pkt_addstring(s->pktout, "keyboard-interactive");
10041 ssh2_pkt_addstring(s->pktout, ""); /* lang */
10042 ssh2_pkt_addstring(s->pktout, ""); /* submethods */
10043 ssh2_pkt_send(ssh, s->pktout);
10045 logevent("Attempting keyboard-interactive authentication");
10047 crWaitUntilV(pktin);
10048 if (pktin->type != SSH2_MSG_USERAUTH_INFO_REQUEST) {
10049 /* Server is not willing to do keyboard-interactive
10050 * at all (or, bizarrely but legally, accepts the
10051 * user without actually issuing any prompts).
10052 * Give up on it entirely. */
10054 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET;
10055 s->kbd_inter_refused = TRUE; /* don't try it again */
10060 * Loop while the server continues to send INFO_REQUESTs.
10062 while (pktin->type == SSH2_MSG_USERAUTH_INFO_REQUEST) {
10064 char *name, *inst, *lang;
10065 int name_len, inst_len, lang_len;
10069 * We've got a fresh USERAUTH_INFO_REQUEST.
10070 * Get the preamble and start building a prompt.
10072 ssh_pkt_getstring(pktin, &name, &name_len);
10073 ssh_pkt_getstring(pktin, &inst, &inst_len);
10074 ssh_pkt_getstring(pktin, &lang, &lang_len);
10075 s->cur_prompt = new_prompts(ssh->frontend);
10076 s->cur_prompt->to_server = TRUE;
10079 * Get any prompt(s) from the packet.
10081 s->num_prompts = ssh_pkt_getuint32(pktin);
10082 for (i = 0; i < s->num_prompts; i++) {
10086 static char noprompt[] =
10087 "<server failed to send prompt>: ";
10089 ssh_pkt_getstring(pktin, &prompt, &prompt_len);
10090 echo = ssh2_pkt_getbool(pktin);
10093 prompt_len = lenof(noprompt)-1;
10095 add_prompt(s->cur_prompt,
10096 dupprintf("%.*s", prompt_len, prompt),
10101 /* FIXME: better prefix to distinguish from
10102 * local prompts? */
10103 s->cur_prompt->name =
10104 dupprintf("SSH server: %.*s", name_len, name);
10105 s->cur_prompt->name_reqd = TRUE;
10107 s->cur_prompt->name =
10108 dupstr("SSH server authentication");
10109 s->cur_prompt->name_reqd = FALSE;
10111 /* We add a prefix to try to make it clear that a prompt
10112 * has come from the server.
10113 * FIXME: ugly to print "Using..." in prompt _every_
10114 * time round. Can this be done more subtly? */
10115 /* Special case: for reasons best known to themselves,
10116 * some servers send k-i requests with no prompts and
10117 * nothing to display. Keep quiet in this case. */
10118 if (s->num_prompts || name_len || inst_len) {
10119 s->cur_prompt->instruction =
10120 dupprintf("Using keyboard-interactive authentication.%s%.*s",
10121 inst_len ? "\n" : "", inst_len, inst);
10122 s->cur_prompt->instr_reqd = TRUE;
10124 s->cur_prompt->instr_reqd = FALSE;
10128 * Display any instructions, and get the user's
10132 int ret; /* not live over crReturn */
10133 ret = get_userpass_input(s->cur_prompt, NULL, 0);
10136 crWaitUntilV(!pktin);
10137 ret = get_userpass_input(s->cur_prompt, in, inlen);
10142 * Failed to get responses. Terminate.
10144 free_prompts(s->cur_prompt);
10145 ssh_disconnect(ssh, NULL, "Unable to authenticate",
10146 SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER,
10153 * Send the response(s) to the server.
10155 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_INFO_RESPONSE);
10156 ssh2_pkt_adduint32(s->pktout, s->num_prompts);
10157 for (i=0; i < s->num_prompts; i++) {
10158 ssh2_pkt_addstring(s->pktout,
10159 s->cur_prompt->prompts[i]->result);
10161 ssh2_pkt_send_with_padding(ssh, s->pktout, 256);
10164 * Free the prompts structure from this iteration.
10165 * If there's another, a new one will be allocated
10166 * when we return to the top of this while loop.
10168 free_prompts(s->cur_prompt);
10171 * Get the next packet in case it's another
10174 crWaitUntilV(pktin);
10179 * We should have SUCCESS or FAILURE now.
10183 } else if (s->can_passwd) {
10186 * Plain old password authentication.
10188 int ret; /* not live over crReturn */
10189 int changereq_first_time; /* not live over crReturn */
10191 ssh->pkt_actx = SSH2_PKTCTX_PASSWORD;
10193 s->cur_prompt = new_prompts(ssh->frontend);
10194 s->cur_prompt->to_server = TRUE;
10195 s->cur_prompt->name = dupstr("SSH password");
10196 add_prompt(s->cur_prompt, dupprintf("%s@%s's password: ",
10201 ret = get_userpass_input(s->cur_prompt, NULL, 0);
10204 crWaitUntilV(!pktin);
10205 ret = get_userpass_input(s->cur_prompt, in, inlen);
10210 * Failed to get responses. Terminate.
10212 free_prompts(s->cur_prompt);
10213 ssh_disconnect(ssh, NULL, "Unable to authenticate",
10214 SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER,
10219 * Squirrel away the password. (We may need it later if
10220 * asked to change it.)
10222 s->password = dupstr(s->cur_prompt->prompts[0]->result);
10223 free_prompts(s->cur_prompt);
10226 * Send the password packet.
10228 * We pad out the password packet to 256 bytes to make
10229 * it harder for an attacker to find the length of the
10232 * Anyone using a password longer than 256 bytes
10233 * probably doesn't have much to worry about from
10234 * people who find out how long their password is!
10236 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
10237 ssh2_pkt_addstring(s->pktout, ssh->username);
10238 ssh2_pkt_addstring(s->pktout, "ssh-connection");
10239 /* service requested */
10240 ssh2_pkt_addstring(s->pktout, "password");
10241 ssh2_pkt_addbool(s->pktout, FALSE);
10242 ssh2_pkt_addstring(s->pktout, s->password);
10243 ssh2_pkt_send_with_padding(ssh, s->pktout, 256);
10244 logevent("Sent password");
10245 s->type = AUTH_TYPE_PASSWORD;
10248 * Wait for next packet, in case it's a password change
10251 crWaitUntilV(pktin);
10252 changereq_first_time = TRUE;
10254 while (pktin->type == SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ) {
10257 * We're being asked for a new password
10258 * (perhaps not for the first time).
10259 * Loop until the server accepts it.
10262 int got_new = FALSE; /* not live over crReturn */
10263 char *prompt; /* not live over crReturn */
10264 int prompt_len; /* not live over crReturn */
10268 if (changereq_first_time)
10269 msg = "Server requested password change";
10271 msg = "Server rejected new password";
10273 c_write_str(ssh, msg);
10274 c_write_str(ssh, "\r\n");
10277 ssh_pkt_getstring(pktin, &prompt, &prompt_len);
10279 s->cur_prompt = new_prompts(ssh->frontend);
10280 s->cur_prompt->to_server = TRUE;
10281 s->cur_prompt->name = dupstr("New SSH password");
10282 s->cur_prompt->instruction =
10283 dupprintf("%.*s", prompt_len, prompt);
10284 s->cur_prompt->instr_reqd = TRUE;
10286 * There's no explicit requirement in the protocol
10287 * for the "old" passwords in the original and
10288 * password-change messages to be the same, and
10289 * apparently some Cisco kit supports password change
10290 * by the user entering a blank password originally
10291 * and the real password subsequently, so,
10292 * reluctantly, we prompt for the old password again.
10294 * (On the other hand, some servers don't even bother
10295 * to check this field.)
10297 add_prompt(s->cur_prompt,
10298 dupstr("Current password (blank for previously entered password): "),
10300 add_prompt(s->cur_prompt, dupstr("Enter new password: "),
10302 add_prompt(s->cur_prompt, dupstr("Confirm new password: "),
10306 * Loop until the user manages to enter the same
10311 ret = get_userpass_input(s->cur_prompt, NULL, 0);
10314 crWaitUntilV(!pktin);
10315 ret = get_userpass_input(s->cur_prompt, in, inlen);
10320 * Failed to get responses. Terminate.
10322 /* burn the evidence */
10323 free_prompts(s->cur_prompt);
10324 smemclr(s->password, strlen(s->password));
10325 sfree(s->password);
10326 ssh_disconnect(ssh, NULL, "Unable to authenticate",
10327 SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER,
10333 * If the user specified a new original password
10334 * (IYSWIM), overwrite any previously specified
10336 * (A side effect is that the user doesn't have to
10337 * re-enter it if they louse up the new password.)
10339 if (s->cur_prompt->prompts[0]->result[0]) {
10340 smemclr(s->password, strlen(s->password));
10341 /* burn the evidence */
10342 sfree(s->password);
10344 dupstr(s->cur_prompt->prompts[0]->result);
10348 * Check the two new passwords match.
10350 got_new = (strcmp(s->cur_prompt->prompts[1]->result,
10351 s->cur_prompt->prompts[2]->result)
10354 /* They don't. Silly user. */
10355 c_write_str(ssh, "Passwords do not match\r\n");
10360 * Send the new password (along with the old one).
10361 * (see above for padding rationale)
10363 s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
10364 ssh2_pkt_addstring(s->pktout, ssh->username);
10365 ssh2_pkt_addstring(s->pktout, "ssh-connection");
10366 /* service requested */
10367 ssh2_pkt_addstring(s->pktout, "password");
10368 ssh2_pkt_addbool(s->pktout, TRUE);
10369 ssh2_pkt_addstring(s->pktout, s->password);
10370 ssh2_pkt_addstring(s->pktout,
10371 s->cur_prompt->prompts[1]->result);
10372 free_prompts(s->cur_prompt);
10373 ssh2_pkt_send_with_padding(ssh, s->pktout, 256);
10374 logevent("Sent new password");
10377 * Now see what the server has to say about it.
10378 * (If it's CHANGEREQ again, it's not happy with the
10381 crWaitUntilV(pktin);
10382 changereq_first_time = FALSE;
10387 * We need to reexamine the current pktin at the top
10388 * of the loop. Either:
10389 * - we weren't asked to change password at all, in
10390 * which case it's a SUCCESS or FAILURE with the
10392 * - we sent a new password, and the server was
10393 * either OK with it (SUCCESS or FAILURE w/partial
10394 * success) or unhappy with the _old_ password
10395 * (FAILURE w/o partial success)
10396 * In any of these cases, we go back to the top of
10397 * the loop and start again.
10402 * We don't need the old password any more, in any
10403 * case. Burn the evidence.
10405 smemclr(s->password, strlen(s->password));
10406 sfree(s->password);
10409 char *str = dupprintf("No supported authentication methods available"
10410 " (server sent: %.*s)",
10413 ssh_disconnect(ssh, str,
10414 "No supported authentication methods available",
10415 SSH2_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE,
10425 ssh->packet_dispatch[SSH2_MSG_USERAUTH_BANNER] = NULL;
10427 /* Clear up various bits and pieces from authentication. */
10428 if (s->publickey_blob) {
10429 sfree(s->publickey_algorithm);
10430 sfree(s->publickey_blob);
10431 sfree(s->publickey_comment);
10433 if (s->agent_response)
10434 sfree(s->agent_response);
10436 if (s->userauth_success && !ssh->bare_connection) {
10438 * We've just received USERAUTH_SUCCESS, and we haven't sent any
10439 * packets since. Signal the transport layer to consider enacting
10440 * delayed compression.
10442 * (Relying on we_are_in is not sufficient, as
10443 * draft-miller-secsh-compression-delayed is quite clear that it
10444 * triggers on USERAUTH_SUCCESS specifically, and we_are_in can
10445 * become set for other reasons.)
10447 do_ssh2_transport(ssh, "enabling delayed compression", -2, NULL);
10450 ssh->channels = newtree234(ssh_channelcmp);
10453 * Set up handlers for some connection protocol messages, so we
10454 * don't have to handle them repeatedly in this coroutine.
10456 ssh->packet_dispatch[SSH2_MSG_CHANNEL_WINDOW_ADJUST] =
10457 ssh2_msg_channel_window_adjust;
10458 ssh->packet_dispatch[SSH2_MSG_GLOBAL_REQUEST] =
10459 ssh2_msg_global_request;
10462 * Create the main session channel.
10464 if (conf_get_int(ssh->conf, CONF_ssh_no_shell)) {
10465 ssh->mainchan = NULL;
10467 ssh->mainchan = snew(struct ssh_channel);
10468 ssh->mainchan->ssh = ssh;
10469 ssh2_channel_init(ssh->mainchan);
10471 if (*conf_get_str(ssh->conf, CONF_ssh_nc_host)) {
10473 * Just start a direct-tcpip channel and use it as the main
10476 ssh_send_port_open(ssh->mainchan,
10477 conf_get_str(ssh->conf, CONF_ssh_nc_host),
10478 conf_get_int(ssh->conf, CONF_ssh_nc_port),
10480 ssh->ncmode = TRUE;
10482 s->pktout = ssh2_chanopen_init(ssh->mainchan, "session");
10483 logevent("Opening session as main channel");
10484 ssh2_pkt_send(ssh, s->pktout);
10485 ssh->ncmode = FALSE;
10487 crWaitUntilV(pktin);
10488 if (pktin->type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
10489 bombout(("Server refused to open channel"));
10491 /* FIXME: error data comes back in FAILURE packet */
10493 if (ssh_pkt_getuint32(pktin) != ssh->mainchan->localid) {
10494 bombout(("Server's channel confirmation cited wrong channel"));
10497 ssh->mainchan->remoteid = ssh_pkt_getuint32(pktin);
10498 ssh->mainchan->halfopen = FALSE;
10499 ssh->mainchan->type = CHAN_MAINSESSION;
10500 ssh->mainchan->v.v2.remwindow = ssh_pkt_getuint32(pktin);
10501 ssh->mainchan->v.v2.remmaxpkt = ssh_pkt_getuint32(pktin);
10502 add234(ssh->channels, ssh->mainchan);
10503 update_specials_menu(ssh->frontend);
10504 logevent("Opened main channel");
10508 * Now we have a channel, make dispatch table entries for
10509 * general channel-based messages.
10511 ssh->packet_dispatch[SSH2_MSG_CHANNEL_DATA] =
10512 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EXTENDED_DATA] =
10513 ssh2_msg_channel_data;
10514 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EOF] = ssh2_msg_channel_eof;
10515 ssh->packet_dispatch[SSH2_MSG_CHANNEL_CLOSE] = ssh2_msg_channel_close;
10516 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_CONFIRMATION] =
10517 ssh2_msg_channel_open_confirmation;
10518 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_FAILURE] =
10519 ssh2_msg_channel_open_failure;
10520 ssh->packet_dispatch[SSH2_MSG_CHANNEL_REQUEST] =
10521 ssh2_msg_channel_request;
10522 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN] =
10523 ssh2_msg_channel_open;
10524 ssh->packet_dispatch[SSH2_MSG_CHANNEL_SUCCESS] = ssh2_msg_channel_response;
10525 ssh->packet_dispatch[SSH2_MSG_CHANNEL_FAILURE] = ssh2_msg_channel_response;
10528 * Now the connection protocol is properly up and running, with
10529 * all those dispatch table entries, so it's safe to let
10530 * downstreams start trying to open extra channels through us.
10532 if (ssh->connshare)
10533 share_activate(ssh->connshare, ssh->v_s);
10535 if (ssh->mainchan && ssh_is_simple(ssh)) {
10537 * This message indicates to the server that we promise
10538 * not to try to run any other channel in parallel with
10539 * this one, so it's safe for it to advertise a very large
10540 * window and leave the flow control to TCP.
10542 s->pktout = ssh2_chanreq_init(ssh->mainchan,
10543 "simple@putty.projects.tartarus.org",
10545 ssh2_pkt_send(ssh, s->pktout);
10549 * Enable port forwardings.
10551 ssh_setup_portfwd(ssh, ssh->conf);
10553 if (ssh->mainchan && !ssh->ncmode) {
10555 * Send the CHANNEL_REQUESTS for the main session channel.
10556 * Each one is handled by its own little asynchronous
10560 /* Potentially enable X11 forwarding. */
10561 if (conf_get_int(ssh->conf, CONF_x11_forward)) {
10563 x11_setup_display(conf_get_str(ssh->conf, CONF_x11_display),
10565 if (!ssh->x11disp) {
10566 /* FIXME: return an error message from x11_setup_display */
10567 logevent("X11 forwarding not enabled: unable to"
10568 " initialise X display");
10570 ssh->x11auth = x11_invent_fake_auth
10571 (ssh->x11authtree, conf_get_int(ssh->conf, CONF_x11_auth));
10572 ssh->x11auth->disp = ssh->x11disp;
10574 ssh2_setup_x11(ssh->mainchan, NULL, NULL);
10578 /* Potentially enable agent forwarding. */
10579 if (ssh_agent_forwarding_permitted(ssh))
10580 ssh2_setup_agent(ssh->mainchan, NULL, NULL);
10582 /* Now allocate a pty for the session. */
10583 if (!conf_get_int(ssh->conf, CONF_nopty))
10584 ssh2_setup_pty(ssh->mainchan, NULL, NULL);
10586 /* Send environment variables. */
10587 ssh2_setup_env(ssh->mainchan, NULL, NULL);
10590 * Start a shell or a remote command. We may have to attempt
10591 * this twice if the config data has provided a second choice
10598 if (ssh->fallback_cmd) {
10599 subsys = conf_get_int(ssh->conf, CONF_ssh_subsys2);
10600 cmd = conf_get_str(ssh->conf, CONF_remote_cmd2);
10602 subsys = conf_get_int(ssh->conf, CONF_ssh_subsys);
10603 cmd = conf_get_str(ssh->conf, CONF_remote_cmd);
10607 s->pktout = ssh2_chanreq_init(ssh->mainchan, "subsystem",
10608 ssh2_response_authconn, NULL);
10609 ssh2_pkt_addstring(s->pktout, cmd);
10611 s->pktout = ssh2_chanreq_init(ssh->mainchan, "exec",
10612 ssh2_response_authconn, NULL);
10613 ssh2_pkt_addstring(s->pktout, cmd);
10615 s->pktout = ssh2_chanreq_init(ssh->mainchan, "shell",
10616 ssh2_response_authconn, NULL);
10618 ssh2_pkt_send(ssh, s->pktout);
10620 crWaitUntilV(pktin);
10622 if (pktin->type != SSH2_MSG_CHANNEL_SUCCESS) {
10623 if (pktin->type != SSH2_MSG_CHANNEL_FAILURE) {
10624 bombout(("Unexpected response to shell/command request:"
10625 " packet type %d", pktin->type));
10629 * We failed to start the command. If this is the
10630 * fallback command, we really are finished; if it's
10631 * not, and if the fallback command exists, try falling
10632 * back to it before complaining.
10634 if (!ssh->fallback_cmd &&
10635 *conf_get_str(ssh->conf, CONF_remote_cmd2)) {
10636 logevent("Primary command failed; attempting fallback");
10637 ssh->fallback_cmd = TRUE;
10640 bombout(("Server refused to start a shell/command"));
10643 logevent("Started a shell/command");
10648 ssh->editing = ssh->echoing = TRUE;
10651 ssh->state = SSH_STATE_SESSION;
10652 if (ssh->size_needed)
10653 ssh_size(ssh, ssh->term_width, ssh->term_height);
10654 if (ssh->eof_needed)
10655 ssh_special(ssh, TS_EOF);
10661 ldisc_echoedit_update(ssh->ldisc); /* cause ldisc to notice changes */
10666 s->try_send = FALSE;
10670 * _All_ the connection-layer packets we expect to
10671 * receive are now handled by the dispatch table.
10672 * Anything that reaches here must be bogus.
10675 bombout(("Strange packet received: type %d", pktin->type));
10677 } else if (ssh->mainchan) {
10679 * We have spare data. Add it to the channel buffer.
10681 ssh2_add_channel_data(ssh->mainchan, (char *)in, inlen);
10682 s->try_send = TRUE;
10686 struct ssh_channel *c;
10688 * Try to send data on all channels if we can.
10690 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++)
10691 if (c->type != CHAN_SHARING)
10692 ssh2_try_send_and_unthrottle(ssh, c);
10700 * Handlers for SSH-2 messages that might arrive at any moment.
10702 static void ssh2_msg_disconnect(Ssh ssh, struct Packet *pktin)
10704 /* log reason code in disconnect message */
10706 int reason, msglen;
10708 reason = ssh_pkt_getuint32(pktin);
10709 ssh_pkt_getstring(pktin, &msg, &msglen);
10711 if (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) {
10712 buf = dupprintf("Received disconnect message (%s)",
10713 ssh2_disconnect_reasons[reason]);
10715 buf = dupprintf("Received disconnect message (unknown"
10716 " type %d)", reason);
10720 buf = dupprintf("Disconnection message text: %.*s",
10723 bombout(("Server sent disconnect message\ntype %d (%s):\n\"%.*s\"",
10725 (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) ?
10726 ssh2_disconnect_reasons[reason] : "unknown",
10731 static void ssh2_msg_debug(Ssh ssh, struct Packet *pktin)
10733 /* log the debug message */
10737 /* XXX maybe we should actually take notice of the return value */
10738 ssh2_pkt_getbool(pktin);
10739 ssh_pkt_getstring(pktin, &msg, &msglen);
10741 logeventf(ssh, "Remote debug message: %.*s", msglen, msg);
10744 static void ssh2_msg_transport(Ssh ssh, struct Packet *pktin)
10746 do_ssh2_transport(ssh, NULL, 0, pktin);
10750 * Called if we receive a packet that isn't allowed by the protocol.
10751 * This only applies to packets whose meaning PuTTY understands.
10752 * Entirely unknown packets are handled below.
10754 static void ssh2_msg_unexpected(Ssh ssh, struct Packet *pktin)
10756 char *buf = dupprintf("Server protocol violation: unexpected %s packet",
10757 ssh2_pkt_type(ssh->pkt_kctx, ssh->pkt_actx,
10759 ssh_disconnect(ssh, NULL, buf, SSH2_DISCONNECT_PROTOCOL_ERROR, FALSE);
10763 static void ssh2_msg_something_unimplemented(Ssh ssh, struct Packet *pktin)
10765 struct Packet *pktout;
10766 pktout = ssh2_pkt_init(SSH2_MSG_UNIMPLEMENTED);
10767 ssh2_pkt_adduint32(pktout, pktin->sequence);
10769 * UNIMPLEMENTED messages MUST appear in the same order as the
10770 * messages they respond to. Hence, never queue them.
10772 ssh2_pkt_send_noqueue(ssh, pktout);
10776 * Handle the top-level SSH-2 protocol.
10778 static void ssh2_protocol_setup(Ssh ssh)
10783 * Most messages cause SSH2_MSG_UNIMPLEMENTED.
10785 for (i = 0; i < 256; i++)
10786 ssh->packet_dispatch[i] = ssh2_msg_something_unimplemented;
10789 * Initially, we only accept transport messages (and a few generic
10790 * ones). do_ssh2_authconn will add more when it starts.
10791 * Messages that are understood but not currently acceptable go to
10792 * ssh2_msg_unexpected.
10794 ssh->packet_dispatch[SSH2_MSG_UNIMPLEMENTED] = ssh2_msg_unexpected;
10795 ssh->packet_dispatch[SSH2_MSG_SERVICE_REQUEST] = ssh2_msg_unexpected;
10796 ssh->packet_dispatch[SSH2_MSG_SERVICE_ACCEPT] = ssh2_msg_unexpected;
10797 ssh->packet_dispatch[SSH2_MSG_KEXINIT] = ssh2_msg_transport;
10798 ssh->packet_dispatch[SSH2_MSG_NEWKEYS] = ssh2_msg_transport;
10799 ssh->packet_dispatch[SSH2_MSG_KEXDH_INIT] = ssh2_msg_transport;
10800 ssh->packet_dispatch[SSH2_MSG_KEXDH_REPLY] = ssh2_msg_transport;
10801 /* ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_REQUEST] = ssh2_msg_transport; duplicate case value */
10802 /* ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_GROUP] = ssh2_msg_transport; duplicate case value */
10803 ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_INIT] = ssh2_msg_transport;
10804 ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_REPLY] = ssh2_msg_transport;
10805 ssh->packet_dispatch[SSH2_MSG_USERAUTH_REQUEST] = ssh2_msg_unexpected;
10806 ssh->packet_dispatch[SSH2_MSG_USERAUTH_FAILURE] = ssh2_msg_unexpected;
10807 ssh->packet_dispatch[SSH2_MSG_USERAUTH_SUCCESS] = ssh2_msg_unexpected;
10808 ssh->packet_dispatch[SSH2_MSG_USERAUTH_BANNER] = ssh2_msg_unexpected;
10809 ssh->packet_dispatch[SSH2_MSG_USERAUTH_PK_OK] = ssh2_msg_unexpected;
10810 /* ssh->packet_dispatch[SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ] = ssh2_msg_unexpected; duplicate case value */
10811 /* ssh->packet_dispatch[SSH2_MSG_USERAUTH_INFO_REQUEST] = ssh2_msg_unexpected; duplicate case value */
10812 ssh->packet_dispatch[SSH2_MSG_USERAUTH_INFO_RESPONSE] = ssh2_msg_unexpected;
10813 ssh->packet_dispatch[SSH2_MSG_GLOBAL_REQUEST] = ssh2_msg_unexpected;
10814 ssh->packet_dispatch[SSH2_MSG_REQUEST_SUCCESS] = ssh2_msg_unexpected;
10815 ssh->packet_dispatch[SSH2_MSG_REQUEST_FAILURE] = ssh2_msg_unexpected;
10816 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN] = ssh2_msg_unexpected;
10817 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_CONFIRMATION] = ssh2_msg_unexpected;
10818 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_FAILURE] = ssh2_msg_unexpected;
10819 ssh->packet_dispatch[SSH2_MSG_CHANNEL_WINDOW_ADJUST] = ssh2_msg_unexpected;
10820 ssh->packet_dispatch[SSH2_MSG_CHANNEL_DATA] = ssh2_msg_unexpected;
10821 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EXTENDED_DATA] = ssh2_msg_unexpected;
10822 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EOF] = ssh2_msg_unexpected;
10823 ssh->packet_dispatch[SSH2_MSG_CHANNEL_CLOSE] = ssh2_msg_unexpected;
10824 ssh->packet_dispatch[SSH2_MSG_CHANNEL_REQUEST] = ssh2_msg_unexpected;
10825 ssh->packet_dispatch[SSH2_MSG_CHANNEL_SUCCESS] = ssh2_msg_unexpected;
10826 ssh->packet_dispatch[SSH2_MSG_CHANNEL_FAILURE] = ssh2_msg_unexpected;
10829 * These messages have a special handler from the start.
10831 ssh->packet_dispatch[SSH2_MSG_DISCONNECT] = ssh2_msg_disconnect;
10832 ssh->packet_dispatch[SSH2_MSG_IGNORE] = ssh_msg_ignore; /* shared with SSH-1 */
10833 ssh->packet_dispatch[SSH2_MSG_DEBUG] = ssh2_msg_debug;
10836 static void ssh2_bare_connection_protocol_setup(Ssh ssh)
10841 * Most messages cause SSH2_MSG_UNIMPLEMENTED.
10843 for (i = 0; i < 256; i++)
10844 ssh->packet_dispatch[i] = ssh2_msg_something_unimplemented;
10847 * Initially, we set all ssh-connection messages to 'unexpected';
10848 * do_ssh2_authconn will fill things in properly. We also handle a
10849 * couple of messages from the transport protocol which aren't
10850 * related to key exchange (UNIMPLEMENTED, IGNORE, DEBUG,
10853 ssh->packet_dispatch[SSH2_MSG_GLOBAL_REQUEST] = ssh2_msg_unexpected;
10854 ssh->packet_dispatch[SSH2_MSG_REQUEST_SUCCESS] = ssh2_msg_unexpected;
10855 ssh->packet_dispatch[SSH2_MSG_REQUEST_FAILURE] = ssh2_msg_unexpected;
10856 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN] = ssh2_msg_unexpected;
10857 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_CONFIRMATION] = ssh2_msg_unexpected;
10858 ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_FAILURE] = ssh2_msg_unexpected;
10859 ssh->packet_dispatch[SSH2_MSG_CHANNEL_WINDOW_ADJUST] = ssh2_msg_unexpected;
10860 ssh->packet_dispatch[SSH2_MSG_CHANNEL_DATA] = ssh2_msg_unexpected;
10861 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EXTENDED_DATA] = ssh2_msg_unexpected;
10862 ssh->packet_dispatch[SSH2_MSG_CHANNEL_EOF] = ssh2_msg_unexpected;
10863 ssh->packet_dispatch[SSH2_MSG_CHANNEL_CLOSE] = ssh2_msg_unexpected;
10864 ssh->packet_dispatch[SSH2_MSG_CHANNEL_REQUEST] = ssh2_msg_unexpected;
10865 ssh->packet_dispatch[SSH2_MSG_CHANNEL_SUCCESS] = ssh2_msg_unexpected;
10866 ssh->packet_dispatch[SSH2_MSG_CHANNEL_FAILURE] = ssh2_msg_unexpected;
10868 ssh->packet_dispatch[SSH2_MSG_UNIMPLEMENTED] = ssh2_msg_unexpected;
10871 * These messages have a special handler from the start.
10873 ssh->packet_dispatch[SSH2_MSG_DISCONNECT] = ssh2_msg_disconnect;
10874 ssh->packet_dispatch[SSH2_MSG_IGNORE] = ssh_msg_ignore;
10875 ssh->packet_dispatch[SSH2_MSG_DEBUG] = ssh2_msg_debug;
10878 static void ssh2_timer(void *ctx, unsigned long now)
10880 Ssh ssh = (Ssh)ctx;
10882 if (ssh->state == SSH_STATE_CLOSED)
10885 if (!ssh->kex_in_progress && !ssh->bare_connection &&
10886 conf_get_int(ssh->conf, CONF_ssh_rekey_time) != 0 &&
10887 now == ssh->next_rekey) {
10888 do_ssh2_transport(ssh, "timeout", -1, NULL);
10892 static void ssh2_protocol(Ssh ssh, const void *vin, int inlen,
10893 struct Packet *pktin)
10895 const unsigned char *in = (const unsigned char *)vin;
10896 if (ssh->state == SSH_STATE_CLOSED)
10900 ssh->incoming_data_size += pktin->encrypted_len;
10901 if (!ssh->kex_in_progress &&
10902 ssh->max_data_size != 0 &&
10903 ssh->incoming_data_size > ssh->max_data_size)
10904 do_ssh2_transport(ssh, "too much data received", -1, NULL);
10908 ssh->packet_dispatch[pktin->type](ssh, pktin);
10909 else if (!ssh->protocol_initial_phase_done)
10910 do_ssh2_transport(ssh, in, inlen, pktin);
10912 do_ssh2_authconn(ssh, in, inlen, pktin);
10915 static void ssh2_bare_connection_protocol(Ssh ssh, const void *vin, int inlen,
10916 struct Packet *pktin)
10918 const unsigned char *in = (const unsigned char *)vin;
10919 if (ssh->state == SSH_STATE_CLOSED)
10923 ssh->packet_dispatch[pktin->type](ssh, pktin);
10925 do_ssh2_authconn(ssh, in, inlen, pktin);
10928 static void ssh_cache_conf_values(Ssh ssh)
10930 ssh->logomitdata = conf_get_int(ssh->conf, CONF_logomitdata);
10934 * Called to set up the connection.
10936 * Returns an error message, or NULL on success.
10938 static const char *ssh_init(void *frontend_handle, void **backend_handle,
10940 const char *host, int port, char **realhost,
10941 int nodelay, int keepalive)
10946 ssh = snew(struct ssh_tag);
10947 ssh->conf = conf_copy(conf);
10948 ssh_cache_conf_values(ssh);
10949 ssh->version = 0; /* when not ready yet */
10951 ssh->cipher = NULL;
10952 ssh->v1_cipher_ctx = NULL;
10953 ssh->crcda_ctx = NULL;
10954 ssh->cscipher = NULL;
10955 ssh->cs_cipher_ctx = NULL;
10956 ssh->sccipher = NULL;
10957 ssh->sc_cipher_ctx = NULL;
10959 ssh->cs_mac_ctx = NULL;
10961 ssh->sc_mac_ctx = NULL;
10962 ssh->cscomp = NULL;
10963 ssh->cs_comp_ctx = NULL;
10964 ssh->sccomp = NULL;
10965 ssh->sc_comp_ctx = NULL;
10967 ssh->kex_ctx = NULL;
10968 ssh->hostkey = NULL;
10969 ssh->hostkey_str = NULL;
10970 ssh->exitcode = -1;
10971 ssh->close_expected = FALSE;
10972 ssh->clean_exit = FALSE;
10973 ssh->state = SSH_STATE_PREPACKET;
10974 ssh->size_needed = FALSE;
10975 ssh->eof_needed = FALSE;
10977 ssh->logctx = NULL;
10978 ssh->deferred_send_data = NULL;
10979 ssh->deferred_len = 0;
10980 ssh->deferred_size = 0;
10981 ssh->fallback_cmd = 0;
10982 ssh->pkt_kctx = SSH2_PKTCTX_NOKEX;
10983 ssh->pkt_actx = SSH2_PKTCTX_NOAUTH;
10984 ssh->x11disp = NULL;
10985 ssh->x11auth = NULL;
10986 ssh->x11authtree = newtree234(x11_authcmp);
10987 ssh->v1_compressing = FALSE;
10988 ssh->v2_outgoing_sequence = 0;
10989 ssh->ssh1_rdpkt_crstate = 0;
10990 ssh->ssh2_rdpkt_crstate = 0;
10991 ssh->ssh2_bare_rdpkt_crstate = 0;
10992 ssh->ssh_gotdata_crstate = 0;
10993 ssh->do_ssh1_connection_crstate = 0;
10994 ssh->do_ssh_init_state = NULL;
10995 ssh->do_ssh_connection_init_state = NULL;
10996 ssh->do_ssh1_login_state = NULL;
10997 ssh->do_ssh2_transport_state = NULL;
10998 ssh->do_ssh2_authconn_state = NULL;
11001 ssh->mainchan = NULL;
11002 ssh->throttled_all = 0;
11003 ssh->v1_stdout_throttling = 0;
11005 ssh->queuelen = ssh->queuesize = 0;
11006 ssh->queueing = FALSE;
11007 ssh->qhead = ssh->qtail = NULL;
11008 ssh->deferred_rekey_reason = NULL;
11009 bufchain_init(&ssh->queued_incoming_data);
11010 ssh->frozen = FALSE;
11011 ssh->username = NULL;
11012 ssh->sent_console_eof = FALSE;
11013 ssh->got_pty = FALSE;
11014 ssh->bare_connection = FALSE;
11015 ssh->X11_fwd_enabled = FALSE;
11016 ssh->connshare = NULL;
11017 ssh->attempting_connshare = FALSE;
11019 *backend_handle = ssh;
11022 if (crypto_startup() == 0)
11023 return "Microsoft high encryption pack not installed!";
11026 ssh->frontend = frontend_handle;
11027 ssh->term_width = conf_get_int(ssh->conf, CONF_width);
11028 ssh->term_height = conf_get_int(ssh->conf, CONF_height);
11030 ssh->channels = NULL;
11031 ssh->rportfwds = NULL;
11032 ssh->portfwds = NULL;
11037 ssh->conn_throttle_count = 0;
11038 ssh->overall_bufsize = 0;
11039 ssh->fallback_cmd = 0;
11041 ssh->protocol = NULL;
11043 ssh->protocol_initial_phase_done = FALSE;
11045 ssh->pinger = NULL;
11047 ssh->incoming_data_size = ssh->outgoing_data_size =
11048 ssh->deferred_data_size = 0L;
11049 ssh->max_data_size = parse_blocksize(conf_get_str(ssh->conf,
11050 CONF_ssh_rekey_data));
11051 ssh->kex_in_progress = FALSE;
11054 ssh->gsslibs = NULL;
11057 random_ref(); /* do this now - may be needed by sharing setup code */
11059 p = connect_to_host(ssh, host, port, realhost, nodelay, keepalive);
11068 static void ssh_free(void *handle)
11070 Ssh ssh = (Ssh) handle;
11071 struct ssh_channel *c;
11072 struct ssh_rportfwd *pf;
11073 struct X11FakeAuth *auth;
11075 if (ssh->v1_cipher_ctx)
11076 ssh->cipher->free_context(ssh->v1_cipher_ctx);
11077 if (ssh->cs_cipher_ctx)
11078 ssh->cscipher->free_context(ssh->cs_cipher_ctx);
11079 if (ssh->sc_cipher_ctx)
11080 ssh->sccipher->free_context(ssh->sc_cipher_ctx);
11081 if (ssh->cs_mac_ctx)
11082 ssh->csmac->free_context(ssh->cs_mac_ctx);
11083 if (ssh->sc_mac_ctx)
11084 ssh->scmac->free_context(ssh->sc_mac_ctx);
11085 if (ssh->cs_comp_ctx) {
11087 ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
11089 zlib_compress_cleanup(ssh->cs_comp_ctx);
11091 if (ssh->sc_comp_ctx) {
11093 ssh->sccomp->decompress_cleanup(ssh->sc_comp_ctx);
11095 zlib_decompress_cleanup(ssh->sc_comp_ctx);
11098 dh_cleanup(ssh->kex_ctx);
11099 sfree(ssh->savedhost);
11101 while (ssh->queuelen-- > 0)
11102 ssh_free_packet(ssh->queue[ssh->queuelen]);
11105 while (ssh->qhead) {
11106 struct queued_handler *qh = ssh->qhead;
11107 ssh->qhead = qh->next;
11110 ssh->qhead = ssh->qtail = NULL;
11112 if (ssh->channels) {
11113 while ((c = delpos234(ssh->channels, 0)) != NULL) {
11116 if (c->u.x11.xconn != NULL)
11117 x11_close(c->u.x11.xconn);
11119 case CHAN_SOCKDATA:
11120 case CHAN_SOCKDATA_DORMANT:
11121 if (c->u.pfd.pf != NULL)
11122 pfd_close(c->u.pfd.pf);
11125 if (ssh->version == 2) {
11126 struct outstanding_channel_request *ocr, *nocr;
11127 ocr = c->v.v2.chanreq_head;
11129 ocr->handler(c, NULL, ocr->ctx);
11134 bufchain_clear(&c->v.v2.outbuffer);
11138 freetree234(ssh->channels);
11139 ssh->channels = NULL;
11142 if (ssh->connshare)
11143 sharestate_free(ssh->connshare);
11145 if (ssh->rportfwds) {
11146 while ((pf = delpos234(ssh->rportfwds, 0)) != NULL)
11148 freetree234(ssh->rportfwds);
11149 ssh->rportfwds = NULL;
11151 sfree(ssh->deferred_send_data);
11153 x11_free_display(ssh->x11disp);
11154 while ((auth = delpos234(ssh->x11authtree, 0)) != NULL)
11155 x11_free_fake_auth(auth);
11156 freetree234(ssh->x11authtree);
11157 sfree(ssh->do_ssh_init_state);
11158 sfree(ssh->do_ssh1_login_state);
11159 sfree(ssh->do_ssh2_transport_state);
11160 sfree(ssh->do_ssh2_authconn_state);
11163 sfree(ssh->fullhostname);
11164 sfree(ssh->hostkey_str);
11165 if (ssh->crcda_ctx) {
11166 crcda_free_context(ssh->crcda_ctx);
11167 ssh->crcda_ctx = NULL;
11170 ssh_do_close(ssh, TRUE);
11171 expire_timer_context(ssh);
11173 pinger_free(ssh->pinger);
11174 bufchain_clear(&ssh->queued_incoming_data);
11175 sfree(ssh->username);
11176 conf_free(ssh->conf);
11179 ssh_gss_cleanup(ssh->gsslibs);
11187 * Reconfigure the SSH backend.
11189 static void ssh_reconfig(void *handle, Conf *conf)
11191 Ssh ssh = (Ssh) handle;
11192 const char *rekeying = NULL;
11193 int rekey_mandatory = FALSE;
11194 unsigned long old_max_data_size;
11197 pinger_reconfig(ssh->pinger, ssh->conf, conf);
11199 ssh_setup_portfwd(ssh, conf);
11201 rekey_time = conf_get_int(conf, CONF_ssh_rekey_time);
11202 if (conf_get_int(ssh->conf, CONF_ssh_rekey_time) != rekey_time &&
11204 unsigned long new_next = ssh->last_rekey + rekey_time*60*TICKSPERSEC;
11205 unsigned long now = GETTICKCOUNT();
11207 if (now - ssh->last_rekey > rekey_time*60*TICKSPERSEC) {
11208 rekeying = "timeout shortened";
11210 ssh->next_rekey = schedule_timer(new_next - now, ssh2_timer, ssh);
11214 old_max_data_size = ssh->max_data_size;
11215 ssh->max_data_size = parse_blocksize(conf_get_str(ssh->conf,
11216 CONF_ssh_rekey_data));
11217 if (old_max_data_size != ssh->max_data_size &&
11218 ssh->max_data_size != 0) {
11219 if (ssh->outgoing_data_size > ssh->max_data_size ||
11220 ssh->incoming_data_size > ssh->max_data_size)
11221 rekeying = "data limit lowered";
11224 if (conf_get_int(ssh->conf, CONF_compression) !=
11225 conf_get_int(conf, CONF_compression)) {
11226 rekeying = "compression setting changed";
11227 rekey_mandatory = TRUE;
11230 for (i = 0; i < CIPHER_MAX; i++)
11231 if (conf_get_int_int(ssh->conf, CONF_ssh_cipherlist, i) !=
11232 conf_get_int_int(conf, CONF_ssh_cipherlist, i)) {
11233 rekeying = "cipher settings changed";
11234 rekey_mandatory = TRUE;
11236 if (conf_get_int(ssh->conf, CONF_ssh2_des_cbc) !=
11237 conf_get_int(conf, CONF_ssh2_des_cbc)) {
11238 rekeying = "cipher settings changed";
11239 rekey_mandatory = TRUE;
11242 conf_free(ssh->conf);
11243 ssh->conf = conf_copy(conf);
11244 ssh_cache_conf_values(ssh);
11246 if (!ssh->bare_connection && rekeying) {
11247 if (!ssh->kex_in_progress) {
11248 do_ssh2_transport(ssh, rekeying, -1, NULL);
11249 } else if (rekey_mandatory) {
11250 ssh->deferred_rekey_reason = rekeying;
11256 * Called to send data down the SSH connection.
11258 static int ssh_send(void *handle, const char *buf, int len)
11260 Ssh ssh = (Ssh) handle;
11262 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
11265 ssh->protocol(ssh, (const unsigned char *)buf, len, 0);
11267 return ssh_sendbuffer(ssh);
11271 * Called to query the current amount of buffered stdin data.
11273 static int ssh_sendbuffer(void *handle)
11275 Ssh ssh = (Ssh) handle;
11276 int override_value;
11278 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
11282 * If the SSH socket itself has backed up, add the total backup
11283 * size on that to any individual buffer on the stdin channel.
11285 override_value = 0;
11286 if (ssh->throttled_all)
11287 override_value = ssh->overall_bufsize;
11289 if (ssh->version == 1) {
11290 return override_value;
11291 } else if (ssh->version == 2) {
11292 if (!ssh->mainchan)
11293 return override_value;
11295 return (override_value +
11296 bufchain_size(&ssh->mainchan->v.v2.outbuffer));
11303 * Called to set the size of the window from SSH's POV.
11305 static void ssh_size(void *handle, int width, int height)
11307 Ssh ssh = (Ssh) handle;
11308 struct Packet *pktout;
11310 ssh->term_width = width;
11311 ssh->term_height = height;
11313 switch (ssh->state) {
11314 case SSH_STATE_BEFORE_SIZE:
11315 case SSH_STATE_PREPACKET:
11316 case SSH_STATE_CLOSED:
11317 break; /* do nothing */
11318 case SSH_STATE_INTERMED:
11319 ssh->size_needed = TRUE; /* buffer for later */
11321 case SSH_STATE_SESSION:
11322 if (!conf_get_int(ssh->conf, CONF_nopty)) {
11323 if (ssh->version == 1) {
11324 send_packet(ssh, SSH1_CMSG_WINDOW_SIZE,
11325 PKT_INT, ssh->term_height,
11326 PKT_INT, ssh->term_width,
11327 PKT_INT, 0, PKT_INT, 0, PKT_END);
11328 } else if (ssh->mainchan) {
11329 pktout = ssh2_chanreq_init(ssh->mainchan, "window-change",
11331 ssh2_pkt_adduint32(pktout, ssh->term_width);
11332 ssh2_pkt_adduint32(pktout, ssh->term_height);
11333 ssh2_pkt_adduint32(pktout, 0);
11334 ssh2_pkt_adduint32(pktout, 0);
11335 ssh2_pkt_send(ssh, pktout);
11343 * Return a list of the special codes that make sense in this
11346 static const struct telnet_special *ssh_get_specials(void *handle)
11348 static const struct telnet_special ssh1_ignore_special[] = {
11349 {"IGNORE message", TS_NOP}
11351 static const struct telnet_special ssh2_ignore_special[] = {
11352 {"IGNORE message", TS_NOP},
11354 static const struct telnet_special ssh2_rekey_special[] = {
11355 {"Repeat key exchange", TS_REKEY},
11357 static const struct telnet_special ssh2_session_specials[] = {
11360 /* These are the signal names defined by RFC 4254.
11361 * They include all the ISO C signals, but are a subset of the POSIX
11362 * required signals. */
11363 {"SIGINT (Interrupt)", TS_SIGINT},
11364 {"SIGTERM (Terminate)", TS_SIGTERM},
11365 {"SIGKILL (Kill)", TS_SIGKILL},
11366 {"SIGQUIT (Quit)", TS_SIGQUIT},
11367 {"SIGHUP (Hangup)", TS_SIGHUP},
11368 {"More signals", TS_SUBMENU},
11369 {"SIGABRT", TS_SIGABRT}, {"SIGALRM", TS_SIGALRM},
11370 {"SIGFPE", TS_SIGFPE}, {"SIGILL", TS_SIGILL},
11371 {"SIGPIPE", TS_SIGPIPE}, {"SIGSEGV", TS_SIGSEGV},
11372 {"SIGUSR1", TS_SIGUSR1}, {"SIGUSR2", TS_SIGUSR2},
11373 {NULL, TS_EXITMENU}
11375 static const struct telnet_special specials_end[] = {
11376 {NULL, TS_EXITMENU}
11378 /* XXX review this length for any changes: */
11379 static struct telnet_special ssh_specials[lenof(ssh2_ignore_special) +
11380 lenof(ssh2_rekey_special) +
11381 lenof(ssh2_session_specials) +
11382 lenof(specials_end)];
11383 Ssh ssh = (Ssh) handle;
11385 #define ADD_SPECIALS(name) \
11387 assert((i + lenof(name)) <= lenof(ssh_specials)); \
11388 memcpy(&ssh_specials[i], name, sizeof name); \
11389 i += lenof(name); \
11392 if (ssh->version == 1) {
11393 /* Don't bother offering IGNORE if we've decided the remote
11394 * won't cope with it, since we wouldn't bother sending it if
11396 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE))
11397 ADD_SPECIALS(ssh1_ignore_special);
11398 } else if (ssh->version == 2) {
11399 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH2_IGNORE))
11400 ADD_SPECIALS(ssh2_ignore_special);
11401 if (!(ssh->remote_bugs & BUG_SSH2_REKEY) && !ssh->bare_connection)
11402 ADD_SPECIALS(ssh2_rekey_special);
11404 ADD_SPECIALS(ssh2_session_specials);
11405 } /* else we're not ready yet */
11408 ADD_SPECIALS(specials_end);
11409 return ssh_specials;
11413 #undef ADD_SPECIALS
11417 * Send special codes. TS_EOF is useful for `plink', so you
11418 * can send an EOF and collect resulting output (e.g. `plink
11421 static void ssh_special(void *handle, Telnet_Special code)
11423 Ssh ssh = (Ssh) handle;
11424 struct Packet *pktout;
11426 if (code == TS_EOF) {
11427 if (ssh->state != SSH_STATE_SESSION) {
11429 * Buffer the EOF in case we are pre-SESSION, so we can
11430 * send it as soon as we reach SESSION.
11432 if (code == TS_EOF)
11433 ssh->eof_needed = TRUE;
11436 if (ssh->version == 1) {
11437 send_packet(ssh, SSH1_CMSG_EOF, PKT_END);
11438 } else if (ssh->mainchan) {
11439 sshfwd_write_eof(ssh->mainchan);
11440 ssh->send_ok = 0; /* now stop trying to read from stdin */
11442 logevent("Sent EOF message");
11443 } else if (code == TS_PING || code == TS_NOP) {
11444 if (ssh->state == SSH_STATE_CLOSED
11445 || ssh->state == SSH_STATE_PREPACKET) return;
11446 if (ssh->version == 1) {
11447 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE))
11448 send_packet(ssh, SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
11450 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH2_IGNORE)) {
11451 pktout = ssh2_pkt_init(SSH2_MSG_IGNORE);
11452 ssh2_pkt_addstring_start(pktout);
11453 ssh2_pkt_send_noqueue(ssh, pktout);
11456 } else if (code == TS_REKEY) {
11457 if (!ssh->kex_in_progress && !ssh->bare_connection &&
11458 ssh->version == 2) {
11459 do_ssh2_transport(ssh, "at user request", -1, NULL);
11461 } else if (code == TS_BRK) {
11462 if (ssh->state == SSH_STATE_CLOSED
11463 || ssh->state == SSH_STATE_PREPACKET) return;
11464 if (ssh->version == 1) {
11465 logevent("Unable to send BREAK signal in SSH-1");
11466 } else if (ssh->mainchan) {
11467 pktout = ssh2_chanreq_init(ssh->mainchan, "break", NULL, NULL);
11468 ssh2_pkt_adduint32(pktout, 0); /* default break length */
11469 ssh2_pkt_send(ssh, pktout);
11472 /* Is is a POSIX signal? */
11473 const char *signame = NULL;
11474 if (code == TS_SIGABRT) signame = "ABRT";
11475 if (code == TS_SIGALRM) signame = "ALRM";
11476 if (code == TS_SIGFPE) signame = "FPE";
11477 if (code == TS_SIGHUP) signame = "HUP";
11478 if (code == TS_SIGILL) signame = "ILL";
11479 if (code == TS_SIGINT) signame = "INT";
11480 if (code == TS_SIGKILL) signame = "KILL";
11481 if (code == TS_SIGPIPE) signame = "PIPE";
11482 if (code == TS_SIGQUIT) signame = "QUIT";
11483 if (code == TS_SIGSEGV) signame = "SEGV";
11484 if (code == TS_SIGTERM) signame = "TERM";
11485 if (code == TS_SIGUSR1) signame = "USR1";
11486 if (code == TS_SIGUSR2) signame = "USR2";
11487 /* The SSH-2 protocol does in principle support arbitrary named
11488 * signals, including signame@domain, but we don't support those. */
11490 /* It's a signal. */
11491 if (ssh->version == 2 && ssh->mainchan) {
11492 pktout = ssh2_chanreq_init(ssh->mainchan, "signal", NULL, NULL);
11493 ssh2_pkt_addstring(pktout, signame);
11494 ssh2_pkt_send(ssh, pktout);
11495 logeventf(ssh, "Sent signal SIG%s", signame);
11498 /* Never heard of it. Do nothing */
11503 void *new_sock_channel(void *handle, struct PortForwarding *pf)
11505 Ssh ssh = (Ssh) handle;
11506 struct ssh_channel *c;
11507 c = snew(struct ssh_channel);
11510 ssh2_channel_init(c);
11511 c->halfopen = TRUE;
11512 c->type = CHAN_SOCKDATA_DORMANT;/* identify channel type */
11514 add234(ssh->channels, c);
11518 unsigned ssh_alloc_sharing_channel(Ssh ssh, void *sharing_ctx)
11520 struct ssh_channel *c;
11521 c = snew(struct ssh_channel);
11524 ssh2_channel_init(c);
11525 c->type = CHAN_SHARING;
11526 c->u.sharing.ctx = sharing_ctx;
11527 add234(ssh->channels, c);
11531 void ssh_delete_sharing_channel(Ssh ssh, unsigned localid)
11533 struct ssh_channel *c;
11535 c = find234(ssh->channels, &localid, ssh_channelfind);
11537 ssh_channel_destroy(c);
11540 void ssh_send_packet_from_downstream(Ssh ssh, unsigned id, int type,
11541 const void *data, int datalen,
11542 const char *additional_log_text)
11544 struct Packet *pkt;
11546 pkt = ssh2_pkt_init(type);
11547 pkt->downstream_id = id;
11548 pkt->additional_log_text = additional_log_text;
11549 ssh2_pkt_adddata(pkt, data, datalen);
11550 ssh2_pkt_send(ssh, pkt);
11554 * This is called when stdout/stderr (the entity to which
11555 * from_backend sends data) manages to clear some backlog.
11557 static void ssh_unthrottle(void *handle, int bufsize)
11559 Ssh ssh = (Ssh) handle;
11562 if (ssh->version == 1) {
11563 if (ssh->v1_stdout_throttling && bufsize < SSH1_BUFFER_LIMIT) {
11564 ssh->v1_stdout_throttling = 0;
11565 ssh_throttle_conn(ssh, -1);
11568 if (ssh->mainchan) {
11569 ssh2_set_window(ssh->mainchan,
11570 bufsize < ssh->mainchan->v.v2.locmaxwin ?
11571 ssh->mainchan->v.v2.locmaxwin - bufsize : 0);
11572 if (ssh_is_simple(ssh))
11575 buflimit = ssh->mainchan->v.v2.locmaxwin;
11576 if (ssh->mainchan->throttling_conn && bufsize <= buflimit) {
11577 ssh->mainchan->throttling_conn = 0;
11578 ssh_throttle_conn(ssh, -1);
11584 * Now process any SSH connection data that was stashed in our
11585 * queue while we were frozen.
11587 ssh_process_queued_incoming_data(ssh);
11590 void ssh_send_port_open(void *channel, const char *hostname, int port,
11593 struct ssh_channel *c = (struct ssh_channel *)channel;
11595 struct Packet *pktout;
11597 logeventf(ssh, "Opening connection to %s:%d for %s", hostname, port, org);
11599 if (ssh->version == 1) {
11600 send_packet(ssh, SSH1_MSG_PORT_OPEN,
11601 PKT_INT, c->localid,
11604 /* PKT_STR, <org:orgport>, */
11607 pktout = ssh2_chanopen_init(c, "direct-tcpip");
11609 char *trimmed_host = host_strduptrim(hostname);
11610 ssh2_pkt_addstring(pktout, trimmed_host);
11611 sfree(trimmed_host);
11613 ssh2_pkt_adduint32(pktout, port);
11615 * We make up values for the originator data; partly it's
11616 * too much hassle to keep track, and partly I'm not
11617 * convinced the server should be told details like that
11618 * about my local network configuration.
11619 * The "originator IP address" is syntactically a numeric
11620 * IP address, and some servers (e.g., Tectia) get upset
11621 * if it doesn't match this syntax.
11623 ssh2_pkt_addstring(pktout, "0.0.0.0");
11624 ssh2_pkt_adduint32(pktout, 0);
11625 ssh2_pkt_send(ssh, pktout);
11629 static int ssh_connected(void *handle)
11631 Ssh ssh = (Ssh) handle;
11632 return ssh->s != NULL;
11635 static int ssh_sendok(void *handle)
11637 Ssh ssh = (Ssh) handle;
11638 return ssh->send_ok;
11641 static int ssh_ldisc(void *handle, int option)
11643 Ssh ssh = (Ssh) handle;
11644 if (option == LD_ECHO)
11645 return ssh->echoing;
11646 if (option == LD_EDIT)
11647 return ssh->editing;
11651 static void ssh_provide_ldisc(void *handle, void *ldisc)
11653 Ssh ssh = (Ssh) handle;
11654 ssh->ldisc = ldisc;
11657 static void ssh_provide_logctx(void *handle, void *logctx)
11659 Ssh ssh = (Ssh) handle;
11660 ssh->logctx = logctx;
11663 static int ssh_return_exitcode(void *handle)
11665 Ssh ssh = (Ssh) handle;
11666 if (ssh->s != NULL)
11669 return (ssh->exitcode >= 0 ? ssh->exitcode : INT_MAX);
11673 * cfg_info for SSH is the protocol running in this session.
11674 * (1 or 2 for the full SSH-1 or SSH-2 protocol; -1 for the bare
11675 * SSH-2 connection protocol, i.e. a downstream; 0 for not-decided-yet.)
11677 static int ssh_cfg_info(void *handle)
11679 Ssh ssh = (Ssh) handle;
11680 if (ssh->version == 0)
11681 return 0; /* don't know yet */
11682 else if (ssh->bare_connection)
11685 return ssh->version;
11689 * Gross hack: pscp will try to start SFTP but fall back to scp1 if
11690 * that fails. This variable is the means by which scp.c can reach
11691 * into the SSH code and find out which one it got.
11693 extern int ssh_fallback_cmd(void *handle)
11695 Ssh ssh = (Ssh) handle;
11696 return ssh->fallback_cmd;
11699 Backend ssh_backend = {
11709 ssh_return_exitcode,
11713 ssh_provide_logctx,
11716 ssh_test_for_upstream,