18 #define logevent(s) { logevent(s); \
19 if ((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)) \
20 { fprintf(stderr, "%s\n", s); fflush(stderr); } }
22 #define bombout(msg) ( ssh_state = SSH_STATE_CLOSED, \
23 (s ? sk_close(s), s = NULL : 0), \
24 connection_fatal msg )
26 #define SSH1_MSG_DISCONNECT 1 /* 0x1 */
27 #define SSH1_SMSG_PUBLIC_KEY 2 /* 0x2 */
28 #define SSH1_CMSG_SESSION_KEY 3 /* 0x3 */
29 #define SSH1_CMSG_USER 4 /* 0x4 */
30 #define SSH1_CMSG_AUTH_RSA 6 /* 0x6 */
31 #define SSH1_SMSG_AUTH_RSA_CHALLENGE 7 /* 0x7 */
32 #define SSH1_CMSG_AUTH_RSA_RESPONSE 8 /* 0x8 */
33 #define SSH1_CMSG_AUTH_PASSWORD 9 /* 0x9 */
34 #define SSH1_CMSG_REQUEST_PTY 10 /* 0xa */
35 #define SSH1_CMSG_WINDOW_SIZE 11 /* 0xb */
36 #define SSH1_CMSG_EXEC_SHELL 12 /* 0xc */
37 #define SSH1_CMSG_EXEC_CMD 13 /* 0xd */
38 #define SSH1_SMSG_SUCCESS 14 /* 0xe */
39 #define SSH1_SMSG_FAILURE 15 /* 0xf */
40 #define SSH1_CMSG_STDIN_DATA 16 /* 0x10 */
41 #define SSH1_SMSG_STDOUT_DATA 17 /* 0x11 */
42 #define SSH1_SMSG_STDERR_DATA 18 /* 0x12 */
43 #define SSH1_CMSG_EOF 19 /* 0x13 */
44 #define SSH1_SMSG_EXIT_STATUS 20 /* 0x14 */
45 #define SSH1_MSG_CHANNEL_OPEN_CONFIRMATION 21 /* 0x15 */
46 #define SSH1_MSG_CHANNEL_OPEN_FAILURE 22 /* 0x16 */
47 #define SSH1_MSG_CHANNEL_DATA 23 /* 0x17 */
48 #define SSH1_MSG_CHANNEL_CLOSE 24 /* 0x18 */
49 #define SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION 25 /* 0x19 */
50 #define SSH1_SMSG_X11_OPEN 27 /* 0x1b */
51 #define SSH1_CMSG_PORT_FORWARD_REQUEST 28 /* 0x1c */
52 #define SSH1_MSG_PORT_OPEN 29 /* 0x1d */
53 #define SSH1_CMSG_AGENT_REQUEST_FORWARDING 30 /* 0x1e */
54 #define SSH1_SMSG_AGENT_OPEN 31 /* 0x1f */
55 #define SSH1_MSG_IGNORE 32 /* 0x20 */
56 #define SSH1_CMSG_EXIT_CONFIRMATION 33 /* 0x21 */
57 #define SSH1_CMSG_X11_REQUEST_FORWARDING 34 /* 0x22 */
58 #define SSH1_CMSG_AUTH_RHOSTS_RSA 35 /* 0x23 */
59 #define SSH1_MSG_DEBUG 36 /* 0x24 */
60 #define SSH1_CMSG_REQUEST_COMPRESSION 37 /* 0x25 */
61 #define SSH1_CMSG_AUTH_TIS 39 /* 0x27 */
62 #define SSH1_SMSG_AUTH_TIS_CHALLENGE 40 /* 0x28 */
63 #define SSH1_CMSG_AUTH_TIS_RESPONSE 41 /* 0x29 */
64 #define SSH1_CMSG_AUTH_CCARD 70 /* 0x46 */
65 #define SSH1_SMSG_AUTH_CCARD_CHALLENGE 71 /* 0x47 */
66 #define SSH1_CMSG_AUTH_CCARD_RESPONSE 72 /* 0x48 */
68 #define SSH1_AUTH_TIS 5 /* 0x5 */
69 #define SSH1_AUTH_CCARD 16 /* 0x10 */
71 #define SSH1_PROTOFLAG_SCREEN_NUMBER 1 /* 0x1 */
72 /* Mask for protoflags we will echo back to server if seen */
73 #define SSH1_PROTOFLAGS_SUPPORTED 0 /* 0x1 */
75 #define SSH2_MSG_DISCONNECT 1 /* 0x1 */
76 #define SSH2_MSG_IGNORE 2 /* 0x2 */
77 #define SSH2_MSG_UNIMPLEMENTED 3 /* 0x3 */
78 #define SSH2_MSG_DEBUG 4 /* 0x4 */
79 #define SSH2_MSG_SERVICE_REQUEST 5 /* 0x5 */
80 #define SSH2_MSG_SERVICE_ACCEPT 6 /* 0x6 */
81 #define SSH2_MSG_KEXINIT 20 /* 0x14 */
82 #define SSH2_MSG_NEWKEYS 21 /* 0x15 */
83 #define SSH2_MSG_KEXDH_INIT 30 /* 0x1e */
84 #define SSH2_MSG_KEXDH_REPLY 31 /* 0x1f */
85 #define SSH2_MSG_KEX_DH_GEX_REQUEST 30 /* 0x1e */
86 #define SSH2_MSG_KEX_DH_GEX_GROUP 31 /* 0x1f */
87 #define SSH2_MSG_KEX_DH_GEX_INIT 32 /* 0x20 */
88 #define SSH2_MSG_KEX_DH_GEX_REPLY 33 /* 0x21 */
89 #define SSH2_MSG_USERAUTH_REQUEST 50 /* 0x32 */
90 #define SSH2_MSG_USERAUTH_FAILURE 51 /* 0x33 */
91 #define SSH2_MSG_USERAUTH_SUCCESS 52 /* 0x34 */
92 #define SSH2_MSG_USERAUTH_BANNER 53 /* 0x35 */
93 #define SSH2_MSG_USERAUTH_PK_OK 60 /* 0x3c */
94 #define SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ 60 /* 0x3c */
95 #define SSH2_MSG_USERAUTH_INFO_REQUEST 60 /* 0x3c */
96 #define SSH2_MSG_USERAUTH_INFO_RESPONSE 61 /* 0x3d */
97 #define SSH2_MSG_GLOBAL_REQUEST 80 /* 0x50 */
98 #define SSH2_MSG_REQUEST_SUCCESS 81 /* 0x51 */
99 #define SSH2_MSG_REQUEST_FAILURE 82 /* 0x52 */
100 #define SSH2_MSG_CHANNEL_OPEN 90 /* 0x5a */
101 #define SSH2_MSG_CHANNEL_OPEN_CONFIRMATION 91 /* 0x5b */
102 #define SSH2_MSG_CHANNEL_OPEN_FAILURE 92 /* 0x5c */
103 #define SSH2_MSG_CHANNEL_WINDOW_ADJUST 93 /* 0x5d */
104 #define SSH2_MSG_CHANNEL_DATA 94 /* 0x5e */
105 #define SSH2_MSG_CHANNEL_EXTENDED_DATA 95 /* 0x5f */
106 #define SSH2_MSG_CHANNEL_EOF 96 /* 0x60 */
107 #define SSH2_MSG_CHANNEL_CLOSE 97 /* 0x61 */
108 #define SSH2_MSG_CHANNEL_REQUEST 98 /* 0x62 */
109 #define SSH2_MSG_CHANNEL_SUCCESS 99 /* 0x63 */
110 #define SSH2_MSG_CHANNEL_FAILURE 100 /* 0x64 */
113 * Packet type contexts, so that ssh2_pkt_type can correctly decode
114 * the ambiguous type numbers back into the correct type strings.
116 #define SSH2_PKTCTX_DHGROUP1 0x0001
117 #define SSH2_PKTCTX_DHGEX 0x0002
118 #define SSH2_PKTCTX_PUBLICKEY 0x0010
119 #define SSH2_PKTCTX_PASSWORD 0x0020
120 #define SSH2_PKTCTX_KBDINTER 0x0040
121 #define SSH2_PKTCTX_AUTH_MASK 0x00F0
123 #define SSH2_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT 1 /* 0x1 */
124 #define SSH2_DISCONNECT_PROTOCOL_ERROR 2 /* 0x2 */
125 #define SSH2_DISCONNECT_KEY_EXCHANGE_FAILED 3 /* 0x3 */
126 #define SSH2_DISCONNECT_HOST_AUTHENTICATION_FAILED 4 /* 0x4 */
127 #define SSH2_DISCONNECT_MAC_ERROR 5 /* 0x5 */
128 #define SSH2_DISCONNECT_COMPRESSION_ERROR 6 /* 0x6 */
129 #define SSH2_DISCONNECT_SERVICE_NOT_AVAILABLE 7 /* 0x7 */
130 #define SSH2_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED 8 /* 0x8 */
131 #define SSH2_DISCONNECT_HOST_KEY_NOT_VERIFIABLE 9 /* 0x9 */
132 #define SSH2_DISCONNECT_CONNECTION_LOST 10 /* 0xa */
133 #define SSH2_DISCONNECT_BY_APPLICATION 11 /* 0xb */
134 #define SSH2_DISCONNECT_TOO_MANY_CONNECTIONS 12 /* 0xc */
135 #define SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER 13 /* 0xd */
136 #define SSH2_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE 14 /* 0xe */
137 #define SSH2_DISCONNECT_ILLEGAL_USER_NAME 15 /* 0xf */
139 static const char *const ssh2_disconnect_reasons[] = {
141 "SSH_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT",
142 "SSH_DISCONNECT_PROTOCOL_ERROR",
143 "SSH_DISCONNECT_KEY_EXCHANGE_FAILED",
144 "SSH_DISCONNECT_HOST_AUTHENTICATION_FAILED",
145 "SSH_DISCONNECT_MAC_ERROR",
146 "SSH_DISCONNECT_COMPRESSION_ERROR",
147 "SSH_DISCONNECT_SERVICE_NOT_AVAILABLE",
148 "SSH_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED",
149 "SSH_DISCONNECT_HOST_KEY_NOT_VERIFIABLE",
150 "SSH_DISCONNECT_CONNECTION_LOST",
151 "SSH_DISCONNECT_BY_APPLICATION",
152 "SSH_DISCONNECT_TOO_MANY_CONNECTIONS",
153 "SSH_DISCONNECT_AUTH_CANCELLED_BY_USER",
154 "SSH_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE",
155 "SSH_DISCONNECT_ILLEGAL_USER_NAME",
158 #define SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED 1 /* 0x1 */
159 #define SSH2_OPEN_CONNECT_FAILED 2 /* 0x2 */
160 #define SSH2_OPEN_UNKNOWN_CHANNEL_TYPE 3 /* 0x3 */
161 #define SSH2_OPEN_RESOURCE_SHORTAGE 4 /* 0x4 */
163 #define SSH2_EXTENDED_DATA_STDERR 1 /* 0x1 */
166 * Various remote-bug flags.
168 #define BUG_CHOKES_ON_SSH1_IGNORE 1
169 #define BUG_SSH2_HMAC 2
170 #define BUG_NEEDS_SSH1_PLAIN_PASSWORD 4
172 static int ssh_pkt_ctx = 0;
174 #define translate(x) if (type == x) return #x
175 #define translatec(x,ctx) if (type == x && (ssh_pkt_ctx & ctx)) return #x
176 char *ssh1_pkt_type(int type)
178 translate(SSH1_MSG_DISCONNECT);
179 translate(SSH1_SMSG_PUBLIC_KEY);
180 translate(SSH1_CMSG_SESSION_KEY);
181 translate(SSH1_CMSG_USER);
182 translate(SSH1_CMSG_AUTH_RSA);
183 translate(SSH1_SMSG_AUTH_RSA_CHALLENGE);
184 translate(SSH1_CMSG_AUTH_RSA_RESPONSE);
185 translate(SSH1_CMSG_AUTH_PASSWORD);
186 translate(SSH1_CMSG_REQUEST_PTY);
187 translate(SSH1_CMSG_WINDOW_SIZE);
188 translate(SSH1_CMSG_EXEC_SHELL);
189 translate(SSH1_CMSG_EXEC_CMD);
190 translate(SSH1_SMSG_SUCCESS);
191 translate(SSH1_SMSG_FAILURE);
192 translate(SSH1_CMSG_STDIN_DATA);
193 translate(SSH1_SMSG_STDOUT_DATA);
194 translate(SSH1_SMSG_STDERR_DATA);
195 translate(SSH1_CMSG_EOF);
196 translate(SSH1_SMSG_EXIT_STATUS);
197 translate(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION);
198 translate(SSH1_MSG_CHANNEL_OPEN_FAILURE);
199 translate(SSH1_MSG_CHANNEL_DATA);
200 translate(SSH1_MSG_CHANNEL_CLOSE);
201 translate(SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION);
202 translate(SSH1_SMSG_X11_OPEN);
203 translate(SSH1_CMSG_PORT_FORWARD_REQUEST);
204 translate(SSH1_MSG_PORT_OPEN);
205 translate(SSH1_CMSG_AGENT_REQUEST_FORWARDING);
206 translate(SSH1_SMSG_AGENT_OPEN);
207 translate(SSH1_MSG_IGNORE);
208 translate(SSH1_CMSG_EXIT_CONFIRMATION);
209 translate(SSH1_CMSG_X11_REQUEST_FORWARDING);
210 translate(SSH1_CMSG_AUTH_RHOSTS_RSA);
211 translate(SSH1_MSG_DEBUG);
212 translate(SSH1_CMSG_REQUEST_COMPRESSION);
213 translate(SSH1_CMSG_AUTH_TIS);
214 translate(SSH1_SMSG_AUTH_TIS_CHALLENGE);
215 translate(SSH1_CMSG_AUTH_TIS_RESPONSE);
216 translate(SSH1_CMSG_AUTH_CCARD);
217 translate(SSH1_SMSG_AUTH_CCARD_CHALLENGE);
218 translate(SSH1_CMSG_AUTH_CCARD_RESPONSE);
221 char *ssh2_pkt_type(int type)
223 translate(SSH2_MSG_DISCONNECT);
224 translate(SSH2_MSG_IGNORE);
225 translate(SSH2_MSG_UNIMPLEMENTED);
226 translate(SSH2_MSG_DEBUG);
227 translate(SSH2_MSG_SERVICE_REQUEST);
228 translate(SSH2_MSG_SERVICE_ACCEPT);
229 translate(SSH2_MSG_KEXINIT);
230 translate(SSH2_MSG_NEWKEYS);
231 translatec(SSH2_MSG_KEXDH_INIT, SSH2_PKTCTX_DHGROUP1);
232 translatec(SSH2_MSG_KEXDH_REPLY, SSH2_PKTCTX_DHGROUP1);
233 translatec(SSH2_MSG_KEX_DH_GEX_REQUEST, SSH2_PKTCTX_DHGEX);
234 translatec(SSH2_MSG_KEX_DH_GEX_GROUP, SSH2_PKTCTX_DHGEX);
235 translatec(SSH2_MSG_KEX_DH_GEX_INIT, SSH2_PKTCTX_DHGEX);
236 translatec(SSH2_MSG_KEX_DH_GEX_REPLY, SSH2_PKTCTX_DHGEX);
237 translate(SSH2_MSG_USERAUTH_REQUEST);
238 translate(SSH2_MSG_USERAUTH_FAILURE);
239 translate(SSH2_MSG_USERAUTH_SUCCESS);
240 translate(SSH2_MSG_USERAUTH_BANNER);
241 translatec(SSH2_MSG_USERAUTH_PK_OK, SSH2_PKTCTX_PUBLICKEY);
242 translatec(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, SSH2_PKTCTX_PASSWORD);
243 translatec(SSH2_MSG_USERAUTH_INFO_REQUEST, SSH2_PKTCTX_KBDINTER);
244 translatec(SSH2_MSG_USERAUTH_INFO_RESPONSE, SSH2_PKTCTX_KBDINTER);
245 translate(SSH2_MSG_GLOBAL_REQUEST);
246 translate(SSH2_MSG_REQUEST_SUCCESS);
247 translate(SSH2_MSG_REQUEST_FAILURE);
248 translate(SSH2_MSG_CHANNEL_OPEN);
249 translate(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
250 translate(SSH2_MSG_CHANNEL_OPEN_FAILURE);
251 translate(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
252 translate(SSH2_MSG_CHANNEL_DATA);
253 translate(SSH2_MSG_CHANNEL_EXTENDED_DATA);
254 translate(SSH2_MSG_CHANNEL_EOF);
255 translate(SSH2_MSG_CHANNEL_CLOSE);
256 translate(SSH2_MSG_CHANNEL_REQUEST);
257 translate(SSH2_MSG_CHANNEL_SUCCESS);
258 translate(SSH2_MSG_CHANNEL_FAILURE);
264 #define GET_32BIT(cp) \
265 (((unsigned long)(unsigned char)(cp)[0] << 24) | \
266 ((unsigned long)(unsigned char)(cp)[1] << 16) | \
267 ((unsigned long)(unsigned char)(cp)[2] << 8) | \
268 ((unsigned long)(unsigned char)(cp)[3]))
270 #define PUT_32BIT(cp, value) { \
271 (cp)[0] = (unsigned char)((value) >> 24); \
272 (cp)[1] = (unsigned char)((value) >> 16); \
273 (cp)[2] = (unsigned char)((value) >> 8); \
274 (cp)[3] = (unsigned char)(value); }
276 enum { PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR, PKT_BIGNUM };
278 /* Coroutine mechanics for the sillier bits of the code */
279 #define crBegin1 static int crLine = 0;
280 #define crBegin2 switch(crLine) { case 0:;
281 #define crBegin crBegin1; crBegin2;
282 #define crFinish(z) } crLine = 0; return (z)
283 #define crFinishV } crLine = 0; return
284 #define crReturn(z) \
286 crLine=__LINE__; return (z); case __LINE__:;\
290 crLine=__LINE__; return; case __LINE__:;\
292 #define crStop(z) do{ crLine = 0; return (z); }while(0)
293 #define crStopV do{ crLine = 0; return; }while(0)
294 #define crWaitUntil(c) do { crReturn(0); } while (!(c))
295 #define crWaitUntilV(c) do { crReturnV; } while (!(c))
297 extern char *x11_init(Socket *, char *, void *);
298 extern void x11_close(Socket);
299 extern int x11_send(Socket, char *, int);
300 extern void x11_invent_auth(char *, int, char *, int);
301 extern void x11_unthrottle(Socket s);
302 extern void x11_override_throttle(Socket s, int enable);
304 extern char *pfd_newconnect(Socket * s, char *hostname, int port, void *c);
305 extern char *pfd_addforward(char *desthost, int destport, int port);
306 extern void pfd_close(Socket s);
307 extern int pfd_send(Socket s, char *data, int len);
308 extern void pfd_confirm(Socket s);
309 extern void pfd_unthrottle(Socket s);
310 extern void pfd_override_throttle(Socket s, int enable);
313 * Buffer management constants. There are several of these for
314 * various different purposes:
316 * - SSH1_BUFFER_LIMIT is the amount of backlog that must build up
317 * on a local data stream before we throttle the whole SSH
318 * connection (in SSH1 only). Throttling the whole connection is
319 * pretty drastic so we set this high in the hope it won't
322 * - SSH_MAX_BACKLOG is the amount of backlog that must build up
323 * on the SSH connection itself before we defensively throttle
324 * _all_ local data streams. This is pretty drastic too (though
325 * thankfully unlikely in SSH2 since the window mechanism should
326 * ensure that the server never has any need to throttle its end
327 * of the connection), so we set this high as well.
329 * - OUR_V2_WINSIZE is the maximum window size we present on SSH2
333 #define SSH1_BUFFER_LIMIT 32768
334 #define SSH_MAX_BACKLOG 32768
335 #define OUR_V2_WINSIZE 16384
337 const static struct ssh_kex *kex_algs[] = {
338 &ssh_diffiehellman_gex,
342 const static struct ssh_signkey *hostkey_algs[] = { &ssh_rsa, &ssh_dss };
344 static void nullmac_key(unsigned char *key)
347 static void nullmac_generate(unsigned char *blk, int len,
351 static int nullmac_verify(unsigned char *blk, int len, unsigned long seq)
355 const static struct ssh_mac ssh_mac_none = {
356 nullmac_key, nullmac_key, nullmac_generate, nullmac_verify, "none", 0
358 const static struct ssh_mac *macs[] = {
359 &ssh_sha1, &ssh_md5, &ssh_mac_none
361 const static struct ssh_mac *buggymacs[] = {
362 &ssh_sha1_buggy, &ssh_md5, &ssh_mac_none
365 static void ssh_comp_none_init(void)
368 static int ssh_comp_none_block(unsigned char *block, int len,
369 unsigned char **outblock, int *outlen)
373 static int ssh_comp_none_disable(void)
377 const static struct ssh_compress ssh_comp_none = {
379 ssh_comp_none_init, ssh_comp_none_block,
380 ssh_comp_none_init, ssh_comp_none_block,
381 ssh_comp_none_disable
383 extern const struct ssh_compress ssh_zlib;
384 const static struct ssh_compress *compressions[] = {
385 &ssh_zlib, &ssh_comp_none
388 enum { /* channel types */
393 CHAN_SOCKDATA_DORMANT /* one the remote hasn't confirmed */
397 * 2-3-4 tree storing channels.
400 unsigned remoteid, localid;
404 struct ssh1_data_channel {
407 struct ssh2_data_channel {
409 unsigned remwindow, remmaxpkt;
414 struct ssh_agent_channel {
415 unsigned char *message;
416 unsigned char msglen[4];
417 int lensofar, totallen;
419 struct ssh_x11_channel {
422 struct ssh_pfd_channel {
429 * 2-3-4 tree storing remote->local port forwardings. SSH 1 and SSH
430 * 2 use this structure in different ways, reflecting SSH 2's
431 * altogether saner approach to port forwarding.
433 * In SSH 1, you arrange a remote forwarding by sending the server
434 * the remote port number, and the local destination host:port.
435 * When a connection comes in, the server sends you back that
436 * host:port pair, and you connect to it. This is a ready-made
437 * security hole if you're not on the ball: a malicious server
438 * could send you back _any_ host:port pair, so if you trustingly
439 * connect to the address it gives you then you've just opened the
440 * entire inside of your corporate network just by connecting
441 * through it to a dodgy SSH server. Hence, we must store a list of
442 * host:port pairs we _are_ trying to forward to, and reject a
443 * connection request from the server if it's not in the list.
445 * In SSH 2, each side of the connection minds its own business and
446 * doesn't send unnecessary information to the other. You arrange a
447 * remote forwarding by sending the server just the remote port
448 * number. When a connection comes in, the server tells you which
449 * of its ports was connected to; and _you_ have to remember what
450 * local host:port pair went with that port number.
452 * Hence: in SSH 1 this structure stores host:port pairs we intend
453 * to allow connections to, and is indexed by those host:port
454 * pairs. In SSH 2 it stores a mapping from source port to
455 * destination host:port pair, and is indexed by source port.
457 struct ssh_rportfwd {
458 unsigned sport, dport;
471 static SHA_State exhash, exhashbase;
473 static Socket s = NULL;
475 static unsigned char session_key[32];
476 static int ssh1_compressing;
477 static int ssh1_remote_protoflags;
478 static int ssh1_local_protoflags;
479 static int ssh_agentfwd_enabled;
480 static int ssh_X11_fwd_enabled;
481 static int ssh_remote_bugs;
482 static const struct ssh_cipher *cipher = NULL;
483 static const struct ssh2_cipher *cscipher = NULL;
484 static const struct ssh2_cipher *sccipher = NULL;
485 static const struct ssh_mac *csmac = NULL;
486 static const struct ssh_mac *scmac = NULL;
487 static const struct ssh_compress *cscomp = NULL;
488 static const struct ssh_compress *sccomp = NULL;
489 static const struct ssh_kex *kex = NULL;
490 static const struct ssh_signkey *hostkey = NULL;
491 static unsigned char ssh2_session_id[20];
492 int (*ssh_get_line) (const char *prompt, char *str, int maxlen,
495 static char *savedhost;
496 static int savedport;
497 static int ssh_send_ok;
498 static int ssh_echoing, ssh_editing;
500 static tree234 *ssh_channels; /* indexed by local id */
501 static struct ssh_channel *mainchan; /* primary session channel */
502 static int ssh_exitcode = -1;
504 static tree234 *ssh_rportfwds;
508 SSH_STATE_BEFORE_SIZE,
512 } ssh_state = SSH_STATE_PREPACKET;
514 static int size_needed = FALSE, eof_needed = FALSE;
516 static struct Packet pktin = { 0, 0, NULL, NULL, 0 };
517 static struct Packet pktout = { 0, 0, NULL, NULL, 0 };
518 static unsigned char *deferred_send_data = NULL;
519 static int deferred_len = 0, deferred_size = 0;
522 * Gross hack: pscp will try to start SFTP but fall back to scp1 if
523 * that fails. This variable is the means by which scp.c can reach
524 * into the SSH code and find out which one it got.
526 int ssh_fallback_cmd = 0;
528 static int ssh_version;
529 static int ssh1_throttle_count;
530 static int ssh_overall_bufsize;
531 static int ssh_throttled_all;
532 static int ssh1_stdout_throttling;
533 static void (*ssh_protocol) (unsigned char *in, int inlen, int ispkt);
534 static void ssh1_protocol(unsigned char *in, int inlen, int ispkt);
535 static void ssh2_protocol(unsigned char *in, int inlen, int ispkt);
536 static void ssh_size(void);
537 static void ssh_special(Telnet_Special);
538 static int ssh2_try_send(struct ssh_channel *c);
539 static void ssh2_add_channel_data(struct ssh_channel *c, char *buf,
541 static void ssh_throttle_all(int enable, int bufsize);
542 static void ssh2_set_window(struct ssh_channel *c, unsigned newwin);
543 static int (*s_rdpkt) (unsigned char **data, int *datalen);
544 static int ssh_sendbuffer(void);
546 static struct rdpkt1_state_tag {
547 long len, pad, biglen, to_read;
548 unsigned long realcrc, gotcrc;
554 static struct rdpkt2_state_tag {
555 long len, pad, payload, packetlen, maclen;
558 unsigned long incoming_sequence;
561 static int ssh_channelcmp(void *av, void *bv)
563 struct ssh_channel *a = (struct ssh_channel *) av;
564 struct ssh_channel *b = (struct ssh_channel *) bv;
565 if (a->localid < b->localid)
567 if (a->localid > b->localid)
571 static int ssh_channelfind(void *av, void *bv)
573 unsigned *a = (unsigned *) av;
574 struct ssh_channel *b = (struct ssh_channel *) bv;
582 static int ssh_rportcmp_ssh1(void *av, void *bv)
584 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
585 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
587 if ( (i = strcmp(a->dhost, b->dhost)) != 0)
588 return i < 0 ? -1 : +1;
589 if (a->dport > b->dport)
591 if (a->dport < b->dport)
596 static int ssh_rportcmp_ssh2(void *av, void *bv)
598 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
599 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
601 if (a->sport > b->sport)
603 if (a->sport < b->sport)
608 static int alloc_channel_id(void)
610 const unsigned CHANNEL_NUMBER_OFFSET = 256;
611 unsigned low, high, mid;
613 struct ssh_channel *c;
616 * First-fit allocation of channel numbers: always pick the
617 * lowest unused one. To do this, binary-search using the
618 * counted B-tree to find the largest channel ID which is in a
619 * contiguous sequence from the beginning. (Precisely
620 * everything in that sequence must have ID equal to its tree
621 * index plus CHANNEL_NUMBER_OFFSET.)
623 tsize = count234(ssh_channels);
627 while (high - low > 1) {
628 mid = (high + low) / 2;
629 c = index234(ssh_channels, mid);
630 if (c->localid == mid + CHANNEL_NUMBER_OFFSET)
631 low = mid; /* this one is fine */
633 high = mid; /* this one is past it */
636 * Now low points to either -1, or the tree index of the
637 * largest ID in the initial sequence.
640 unsigned i = low + 1 + CHANNEL_NUMBER_OFFSET;
641 assert(NULL == find234(ssh_channels, &i, ssh_channelfind));
643 return low + 1 + CHANNEL_NUMBER_OFFSET;
646 static void c_write(char *buf, int len)
648 if ((flags & FLAG_STDERR)) {
650 for (i = 0; i < len; i++)
652 fputc(buf[i], stderr);
655 from_backend(1, buf, len);
658 static void c_write_untrusted(char *buf, int len)
661 for (i = 0; i < len; i++) {
664 else if ((buf[i] & 0x60) || (buf[i] == '\r'))
669 static void c_write_str(char *buf)
671 c_write(buf, strlen(buf));
675 * Collect incoming data in the incoming packet buffer.
676 * Decipher and verify the packet when it is completely read.
677 * Drop SSH1_MSG_DEBUG and SSH1_MSG_IGNORE packets.
678 * Update the *data and *datalen variables.
679 * Return the additional nr of bytes needed, or 0 when
680 * a complete packet is available.
682 static int ssh1_rdpkt(unsigned char **data, int *datalen)
684 struct rdpkt1_state_tag *st = &rdpkt1_state;
693 for (st->i = st->len = 0; st->i < 4; st->i++) {
694 while ((*datalen) == 0)
696 st->len = (st->len << 8) + **data;
697 (*data)++, (*datalen)--;
700 st->pad = 8 - (st->len % 8);
701 st->biglen = st->len + st->pad;
702 pktin.length = st->len - 5;
704 if (pktin.maxlen < st->biglen) {
705 pktin.maxlen = st->biglen;
706 pktin.data = (pktin.data == NULL ? smalloc(st->biglen + APIEXTRA) :
707 srealloc(pktin.data, st->biglen + APIEXTRA));
709 fatalbox("Out of memory");
712 st->to_read = st->biglen;
714 while (st->to_read > 0) {
715 st->chunk = st->to_read;
716 while ((*datalen) == 0)
717 crReturn(st->to_read);
718 if (st->chunk > (*datalen))
719 st->chunk = (*datalen);
720 memcpy(st->p, *data, st->chunk);
722 *datalen -= st->chunk;
724 st->to_read -= st->chunk;
727 if (cipher && detect_attack(pktin.data, st->biglen, NULL)) {
728 bombout(("Network attack (CRC compensation) detected!"));
733 cipher->decrypt(pktin.data, st->biglen);
735 st->realcrc = crc32(pktin.data, st->biglen - 4);
736 st->gotcrc = GET_32BIT(pktin.data + st->biglen - 4);
737 if (st->gotcrc != st->realcrc) {
738 bombout(("Incorrect CRC received on packet"));
742 pktin.body = pktin.data + st->pad + 1;
744 if (ssh1_compressing) {
745 unsigned char *decompblk;
747 zlib_decompress_block(pktin.body - 1, pktin.length + 1,
748 &decompblk, &decomplen);
750 if (pktin.maxlen < st->pad + decomplen) {
751 pktin.maxlen = st->pad + decomplen;
752 pktin.data = srealloc(pktin.data, pktin.maxlen + APIEXTRA);
753 pktin.body = pktin.data + st->pad + 1;
755 fatalbox("Out of memory");
758 memcpy(pktin.body - 1, decompblk, decomplen);
760 pktin.length = decomplen - 1;
763 pktin.type = pktin.body[-1];
765 log_packet(PKT_INCOMING, pktin.type, ssh1_pkt_type(pktin.type),
766 pktin.body, pktin.length);
768 if (pktin.type == SSH1_SMSG_STDOUT_DATA ||
769 pktin.type == SSH1_SMSG_STDERR_DATA ||
770 pktin.type == SSH1_MSG_DEBUG ||
771 pktin.type == SSH1_SMSG_AUTH_TIS_CHALLENGE ||
772 pktin.type == SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
773 long strlen = GET_32BIT(pktin.body);
774 if (strlen + 4 != pktin.length) {
775 bombout(("Received data packet with bogus string length"));
780 if (pktin.type == SSH1_MSG_DEBUG) {
781 /* log debug message */
783 int strlen = GET_32BIT(pktin.body);
784 strcpy(buf, "Remote: ");
787 memcpy(buf + 8, pktin.body + 4, strlen);
788 buf[8 + strlen] = '\0';
791 } else if (pktin.type == SSH1_MSG_IGNORE) {
796 if (pktin.type == SSH1_MSG_DISCONNECT) {
797 /* log reason code in disconnect message */
799 unsigned msglen = GET_32BIT(pktin.body);
801 strcpy(buf, "Remote sent disconnect: ");
802 nowlen = strlen(buf);
803 if (msglen > sizeof(buf) - nowlen - 1)
804 msglen = sizeof(buf) - nowlen - 1;
805 memcpy(buf + nowlen, pktin.body + 4, msglen);
806 buf[nowlen + msglen] = '\0';
808 bombout(("Server sent disconnect message:\n\"%s\"", buf+nowlen));
815 static int ssh2_rdpkt(unsigned char **data, int *datalen)
817 struct rdpkt2_state_tag *st = &rdpkt2_state;
825 st->cipherblk = sccipher->blksize;
828 if (st->cipherblk < 8)
831 if (pktin.maxlen < st->cipherblk) {
832 pktin.maxlen = st->cipherblk;
835 NULL ? smalloc(st->cipherblk +
836 APIEXTRA) : srealloc(pktin.data,
840 fatalbox("Out of memory");
844 * Acquire and decrypt the first block of the packet. This will
845 * contain the length and padding details.
847 for (st->i = st->len = 0; st->i < st->cipherblk; st->i++) {
848 while ((*datalen) == 0)
849 crReturn(st->cipherblk - st->i);
850 pktin.data[st->i] = *(*data)++;
855 sccipher->decrypt(pktin.data, st->cipherblk);
858 * Now get the length and padding figures.
860 st->len = GET_32BIT(pktin.data);
861 st->pad = pktin.data[4];
864 * This enables us to deduce the payload length.
866 st->payload = st->len - st->pad - 1;
868 pktin.length = st->payload + 5;
871 * So now we can work out the total packet length.
873 st->packetlen = st->len + 4;
874 st->maclen = scmac ? scmac->len : 0;
877 * Adjust memory allocation if packet is too big.
879 if (pktin.maxlen < st->packetlen + st->maclen) {
880 pktin.maxlen = st->packetlen + st->maclen;
883 NULL ? smalloc(pktin.maxlen + APIEXTRA) : srealloc(pktin.data,
888 fatalbox("Out of memory");
892 * Read and decrypt the remainder of the packet.
894 for (st->i = st->cipherblk; st->i < st->packetlen + st->maclen;
896 while ((*datalen) == 0)
897 crReturn(st->packetlen + st->maclen - st->i);
898 pktin.data[st->i] = *(*data)++;
901 /* Decrypt everything _except_ the MAC. */
903 sccipher->decrypt(pktin.data + st->cipherblk,
904 st->packetlen - st->cipherblk);
910 && !scmac->verify(pktin.data, st->len + 4,
911 st->incoming_sequence)) {
912 bombout(("Incorrect MAC received on packet"));
915 st->incoming_sequence++; /* whether or not we MACed */
918 * Decompress packet payload.
921 unsigned char *newpayload;
923 if (sccomp && sccomp->decompress(pktin.data + 5, pktin.length - 5,
924 &newpayload, &newlen)) {
925 if (pktin.maxlen < newlen + 5) {
926 pktin.maxlen = newlen + 5;
929 NULL ? smalloc(pktin.maxlen +
930 APIEXTRA) : srealloc(pktin.data,
934 fatalbox("Out of memory");
936 pktin.length = 5 + newlen;
937 memcpy(pktin.data + 5, newpayload, newlen);
943 pktin.type = pktin.data[5];
945 log_packet(PKT_INCOMING, pktin.type, ssh2_pkt_type(pktin.type),
946 pktin.data+6, pktin.length-6);
948 if (pktin.type == SSH2_MSG_IGNORE || pktin.type == SSH2_MSG_DEBUG)
949 goto next_packet; /* FIXME: print DEBUG message */
951 if (pktin.type == SSH2_MSG_DISCONNECT) {
952 /* log reason code in disconnect message */
954 int reason = GET_32BIT(pktin.data + 6);
955 unsigned msglen = GET_32BIT(pktin.data + 10);
957 if (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) {
958 sprintf(buf, "Received disconnect message (%s)",
959 ssh2_disconnect_reasons[reason]);
961 sprintf(buf, "Received disconnect message (unknown type %d)",
965 strcpy(buf, "Disconnection message text: ");
966 nowlen = strlen(buf);
967 if (msglen > sizeof(buf) - nowlen - 1)
968 msglen = sizeof(buf) - nowlen - 1;
969 memcpy(buf + nowlen, pktin.data + 14, msglen);
970 buf[nowlen + msglen] = '\0';
972 bombout(("Server sent disconnect message\ntype %d (%s):\n\"%s\"",
974 (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) ?
975 ssh2_disconnect_reasons[reason] : "unknown",
983 static void ssh1_pktout_size(int len)
987 len += 5; /* type and CRC */
991 pktout.length = len - 5;
992 if (pktout.maxlen < biglen) {
993 pktout.maxlen = biglen;
995 /* Allocate enough buffer space for extra block
996 * for MS CryptEncrypt() */
997 pktout.data = (pktout.data == NULL ? smalloc(biglen + 12) :
998 srealloc(pktout.data, biglen + 12));
1000 pktout.data = (pktout.data == NULL ? smalloc(biglen + 4) :
1001 srealloc(pktout.data, biglen + 4));
1004 fatalbox("Out of memory");
1006 pktout.body = pktout.data + 4 + pad + 1;
1009 static void s_wrpkt_start(int type, int len)
1011 ssh1_pktout_size(len);
1015 static int s_wrpkt_prepare(void)
1017 int pad, len, biglen, i;
1020 pktout.body[-1] = pktout.type;
1022 log_packet(PKT_OUTGOING, pktout.type, ssh1_pkt_type(pktout.type),
1023 pktout.body, pktout.length);
1025 if (ssh1_compressing) {
1026 unsigned char *compblk;
1028 zlib_compress_block(pktout.body - 1, pktout.length + 1,
1029 &compblk, &complen);
1030 ssh1_pktout_size(complen - 1);
1031 memcpy(pktout.body - 1, compblk, complen);
1035 len = pktout.length + 5; /* type and CRC */
1036 pad = 8 - (len % 8);
1039 for (i = 0; i < pad; i++)
1040 pktout.data[i + 4] = random_byte();
1041 crc = crc32(pktout.data + 4, biglen - 4);
1042 PUT_32BIT(pktout.data + biglen, crc);
1043 PUT_32BIT(pktout.data, len);
1046 cipher->encrypt(pktout.data + 4, biglen);
1051 static void s_wrpkt(void)
1054 len = s_wrpkt_prepare();
1055 backlog = sk_write(s, pktout.data, len);
1056 if (backlog > SSH_MAX_BACKLOG)
1057 ssh_throttle_all(1, backlog);
1060 static void s_wrpkt_defer(void)
1063 len = s_wrpkt_prepare();
1064 if (deferred_len + len > deferred_size) {
1065 deferred_size = deferred_len + len + 128;
1066 deferred_send_data = srealloc(deferred_send_data, deferred_size);
1068 memcpy(deferred_send_data + deferred_len, pktout.data, len);
1069 deferred_len += len;
1073 * Construct a packet with the specified contents.
1075 static void construct_packet(int pkttype, va_list ap1, va_list ap2)
1077 unsigned char *p, *argp, argchar;
1078 unsigned long argint;
1079 int pktlen, argtype, arglen;
1083 while ((argtype = va_arg(ap1, int)) != PKT_END) {
1086 (void) va_arg(ap1, int);
1090 (void) va_arg(ap1, char);
1094 (void) va_arg(ap1, unsigned char *);
1095 arglen = va_arg(ap1, int);
1099 argp = va_arg(ap1, unsigned char *);
1100 arglen = strlen(argp);
1101 pktlen += 4 + arglen;
1104 bn = va_arg(ap1, Bignum);
1105 pktlen += ssh1_bignum_length(bn);
1112 s_wrpkt_start(pkttype, pktlen);
1115 while ((argtype = va_arg(ap2, int)) != PKT_END) {
1118 argint = va_arg(ap2, int);
1119 PUT_32BIT(p, argint);
1123 argchar = va_arg(ap2, unsigned char);
1128 argp = va_arg(ap2, unsigned char *);
1129 arglen = va_arg(ap2, int);
1130 memcpy(p, argp, arglen);
1134 argp = va_arg(ap2, unsigned char *);
1135 arglen = strlen(argp);
1136 PUT_32BIT(p, arglen);
1137 memcpy(p + 4, argp, arglen);
1141 bn = va_arg(ap2, Bignum);
1142 p += ssh1_write_bignum(p, bn);
1148 static void send_packet(int pkttype, ...)
1151 va_start(ap1, pkttype);
1152 va_start(ap2, pkttype);
1153 construct_packet(pkttype, ap1, ap2);
1157 static void defer_packet(int pkttype, ...)
1160 va_start(ap1, pkttype);
1161 va_start(ap2, pkttype);
1162 construct_packet(pkttype, ap1, ap2);
1166 static int ssh_versioncmp(char *a, char *b)
1169 unsigned long av, bv;
1171 av = strtoul(a, &ae, 10);
1172 bv = strtoul(b, &be, 10);
1174 return (av < bv ? -1 : +1);
1179 av = strtoul(ae, &ae, 10);
1180 bv = strtoul(be, &be, 10);
1182 return (av < bv ? -1 : +1);
1188 * Utility routines for putting an SSH-protocol `string' and
1189 * `uint32' into a SHA state.
1192 static void sha_string(SHA_State * s, void *str, int len)
1194 unsigned char lenblk[4];
1195 PUT_32BIT(lenblk, len);
1196 SHA_Bytes(s, lenblk, 4);
1197 SHA_Bytes(s, str, len);
1200 static void sha_uint32(SHA_State * s, unsigned i)
1202 unsigned char intblk[4];
1203 PUT_32BIT(intblk, i);
1204 SHA_Bytes(s, intblk, 4);
1208 * SSH2 packet construction functions.
1210 static void ssh2_pkt_ensure(int length)
1212 if (pktout.maxlen < length) {
1213 pktout.maxlen = length + 256;
1216 NULL ? smalloc(pktout.maxlen +
1217 APIEXTRA) : srealloc(pktout.data,
1221 fatalbox("Out of memory");
1224 static void ssh2_pkt_adddata(void *data, int len)
1226 pktout.length += len;
1227 ssh2_pkt_ensure(pktout.length);
1228 memcpy(pktout.data + pktout.length - len, data, len);
1230 static void ssh2_pkt_addbyte(unsigned char byte)
1232 ssh2_pkt_adddata(&byte, 1);
1234 static void ssh2_pkt_init(int pkt_type)
1237 ssh2_pkt_addbyte((unsigned char) pkt_type);
1239 static void ssh2_pkt_addbool(unsigned char value)
1241 ssh2_pkt_adddata(&value, 1);
1243 static void ssh2_pkt_adduint32(unsigned long value)
1246 PUT_32BIT(x, value);
1247 ssh2_pkt_adddata(x, 4);
1249 static void ssh2_pkt_addstring_start(void)
1251 ssh2_pkt_adduint32(0);
1252 pktout.savedpos = pktout.length;
1254 static void ssh2_pkt_addstring_str(char *data)
1256 ssh2_pkt_adddata(data, strlen(data));
1257 PUT_32BIT(pktout.data + pktout.savedpos - 4,
1258 pktout.length - pktout.savedpos);
1260 static void ssh2_pkt_addstring_data(char *data, int len)
1262 ssh2_pkt_adddata(data, len);
1263 PUT_32BIT(pktout.data + pktout.savedpos - 4,
1264 pktout.length - pktout.savedpos);
1266 static void ssh2_pkt_addstring(char *data)
1268 ssh2_pkt_addstring_start();
1269 ssh2_pkt_addstring_str(data);
1271 static char *ssh2_mpint_fmt(Bignum b, int *len)
1274 int i, n = (bignum_bitcount(b) + 7) / 8;
1277 fatalbox("out of memory");
1279 for (i = 1; i <= n; i++)
1280 p[i] = bignum_byte(b, n - i);
1282 while (i <= n && p[i] == 0 && (p[i + 1] & 0x80) == 0)
1284 memmove(p, p + i, n + 1 - i);
1288 static void ssh2_pkt_addmp(Bignum b)
1292 p = ssh2_mpint_fmt(b, &len);
1293 ssh2_pkt_addstring_start();
1294 ssh2_pkt_addstring_data(p, len);
1299 * Construct an SSH2 final-form packet: compress it, encrypt it,
1300 * put the MAC on it. Final packet, ready to be sent, is stored in
1301 * pktout.data. Total length is returned.
1303 static int ssh2_pkt_construct(void)
1305 int cipherblk, maclen, padding, i;
1306 static unsigned long outgoing_sequence = 0;
1308 log_packet(PKT_OUTGOING, pktout.data[5], ssh2_pkt_type(pktout.data[5]),
1309 pktout.data + 6, pktout.length - 6);
1312 * Compress packet payload.
1315 unsigned char *newpayload;
1317 if (cscomp && cscomp->compress(pktout.data + 5, pktout.length - 5,
1318 &newpayload, &newlen)) {
1320 ssh2_pkt_adddata(newpayload, newlen);
1326 * Add padding. At least four bytes, and must also bring total
1327 * length (minus MAC) up to a multiple of the block size.
1329 cipherblk = cscipher ? cscipher->blksize : 8; /* block size */
1330 cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */
1333 (cipherblk - (pktout.length + padding) % cipherblk) % cipherblk;
1334 maclen = csmac ? csmac->len : 0;
1335 ssh2_pkt_ensure(pktout.length + padding + maclen);
1336 pktout.data[4] = padding;
1337 for (i = 0; i < padding; i++)
1338 pktout.data[pktout.length + i] = random_byte();
1339 PUT_32BIT(pktout.data, pktout.length + padding - 4);
1341 csmac->generate(pktout.data, pktout.length + padding,
1343 outgoing_sequence++; /* whether or not we MACed */
1346 cscipher->encrypt(pktout.data, pktout.length + padding);
1348 /* Ready-to-send packet starts at pktout.data. We return length. */
1349 return pktout.length + padding + maclen;
1353 * Construct and send an SSH2 packet immediately.
1355 static void ssh2_pkt_send(void)
1359 len = ssh2_pkt_construct();
1360 backlog = sk_write(s, pktout.data, len);
1361 if (backlog > SSH_MAX_BACKLOG)
1362 ssh_throttle_all(1, backlog);
1366 * Construct an SSH2 packet and add it to a deferred data block.
1367 * Useful for sending multiple packets in a single sk_write() call,
1368 * to prevent a traffic-analysing listener from being able to work
1369 * out the length of any particular packet (such as the password
1372 * Note that because SSH2 sequence-numbers its packets, this can
1373 * NOT be used as an m4-style `defer' allowing packets to be
1374 * constructed in one order and sent in another.
1376 static void ssh2_pkt_defer(void)
1378 int len = ssh2_pkt_construct();
1379 if (deferred_len + len > deferred_size) {
1380 deferred_size = deferred_len + len + 128;
1381 deferred_send_data = srealloc(deferred_send_data, deferred_size);
1383 memcpy(deferred_send_data + deferred_len, pktout.data, len);
1384 deferred_len += len;
1388 * Send the whole deferred data block constructed by
1389 * ssh2_pkt_defer() or SSH1's defer_packet().
1391 static void ssh_pkt_defersend(void)
1394 backlog = sk_write(s, deferred_send_data, deferred_len);
1395 deferred_len = deferred_size = 0;
1396 sfree(deferred_send_data);
1397 deferred_send_data = NULL;
1398 if (backlog > SSH_MAX_BACKLOG)
1399 ssh_throttle_all(1, backlog);
1403 void bndebug(char *string, Bignum b)
1407 p = ssh2_mpint_fmt(b, &len);
1408 debug(("%s", string));
1409 for (i = 0; i < len; i++)
1410 debug((" %02x", p[i]));
1416 static void sha_mpint(SHA_State * s, Bignum b)
1420 p = ssh2_mpint_fmt(b, &len);
1421 sha_string(s, p, len);
1426 * SSH2 packet decode functions.
1428 static unsigned long ssh2_pkt_getuint32(void)
1430 unsigned long value;
1431 if (pktin.length - pktin.savedpos < 4)
1432 return 0; /* arrgh, no way to decline (FIXME?) */
1433 value = GET_32BIT(pktin.data + pktin.savedpos);
1434 pktin.savedpos += 4;
1437 static int ssh2_pkt_getbool(void)
1439 unsigned long value;
1440 if (pktin.length - pktin.savedpos < 1)
1441 return 0; /* arrgh, no way to decline (FIXME?) */
1442 value = pktin.data[pktin.savedpos] != 0;
1446 static void ssh2_pkt_getstring(char **p, int *length)
1449 if (pktin.length - pktin.savedpos < 4)
1451 *length = GET_32BIT(pktin.data + pktin.savedpos);
1452 pktin.savedpos += 4;
1453 if (pktin.length - pktin.savedpos < *length)
1455 *p = pktin.data + pktin.savedpos;
1456 pktin.savedpos += *length;
1458 static Bignum ssh2_pkt_getmp(void)
1464 ssh2_pkt_getstring(&p, &length);
1468 bombout(("internal error: Can't handle negative mpints"));
1471 b = bignum_from_bytes(p, length);
1476 * Examine the remote side's version string and compare it against
1477 * a list of known buggy implementations.
1479 static void ssh_detect_bugs(char *vstring)
1481 char *imp; /* pointer to implementation part */
1483 imp += strcspn(imp, "-");
1485 imp += strcspn(imp, "-");
1488 ssh_remote_bugs = 0;
1490 if (!strcmp(imp, "1.2.18") || !strcmp(imp, "1.2.19") ||
1491 !strcmp(imp, "1.2.20") || !strcmp(imp, "1.2.21") ||
1492 !strcmp(imp, "1.2.22") || !strcmp(imp, "Cisco-1.25")) {
1494 * These versions don't support SSH1_MSG_IGNORE, so we have
1495 * to use a different defence against password length
1498 ssh_remote_bugs |= BUG_CHOKES_ON_SSH1_IGNORE;
1499 logevent("We believe remote version has SSH1 ignore bug");
1502 if (!strcmp(imp, "Cisco-1.25")) {
1504 * These versions need a plain password sent; they can't
1505 * handle having a null and a random length of data after
1508 ssh_remote_bugs |= BUG_NEEDS_SSH1_PLAIN_PASSWORD;
1509 logevent("We believe remote version needs a plain SSH1 password");
1512 if (!strncmp(imp, "2.1.0", 5) || !strncmp(imp, "2.0.", 4) ||
1513 !strncmp(imp, "2.2.0", 5) || !strncmp(imp, "2.3.0", 5) ||
1514 !strncmp(imp, "2.1 ", 4)) {
1516 * These versions have the HMAC bug.
1518 ssh_remote_bugs |= BUG_SSH2_HMAC;
1519 logevent("We believe remote version has SSH2 HMAC bug");
1523 static int do_ssh_init(unsigned char c)
1526 static char version[10];
1527 static char *vstring;
1528 static int vstrsize;
1534 /* Search for the string "SSH-" in the input. */
1537 static const int transS[] = { 1, 2, 2, 1 };
1538 static const int transH[] = { 0, 0, 3, 0 };
1539 static const int transminus[] = { 0, 0, 0, -1 };
1550 crReturn(1); /* get another character */
1554 vstring = smalloc(vstrsize);
1555 strcpy(vstring, "SSH-");
1559 crReturn(1); /* get another char */
1560 if (vslen >= vstrsize - 1) {
1562 vstring = srealloc(vstring, vstrsize);
1564 vstring[vslen++] = c;
1569 } else if (i < sizeof(version) - 1)
1571 } else if (c == '\n')
1575 ssh_agentfwd_enabled = FALSE;
1576 rdpkt2_state.incoming_sequence = 0;
1579 vlog = smalloc(20 + vslen);
1580 vstring[strcspn (vstring, "\r\n")] = '\0'; /* remove end-of-line chars */
1581 sprintf(vlog, "Server version: %s", vstring);
1583 ssh_detect_bugs(vstring);
1587 * Server version "1.99" means we can choose whether we use v1
1588 * or v2 protocol. Choice is based on cfg.sshprot.
1590 if (ssh_versioncmp(version, cfg.sshprot == 1 ? "2.0" : "1.99") >= 0) {
1592 * This is a v2 server. Begin v2 protocol.
1594 char verstring[80], vlog[100];
1595 sprintf(verstring, "SSH-2.0-%s", sshver);
1596 SHA_Init(&exhashbase);
1598 * Hash our version string and their version string.
1600 sha_string(&exhashbase, verstring, strlen(verstring));
1601 sha_string(&exhashbase, vstring, strcspn(vstring, "\r\n"));
1602 sprintf(vlog, "We claim version: %s", verstring);
1604 strcat(verstring, "\n");
1605 logevent("Using SSH protocol version 2");
1606 sk_write(s, verstring, strlen(verstring));
1607 ssh_protocol = ssh2_protocol;
1609 s_rdpkt = ssh2_rdpkt;
1612 * This is a v1 server. Begin v1 protocol.
1614 char verstring[80], vlog[100];
1615 sprintf(verstring, "SSH-%s-%s",
1616 (ssh_versioncmp(version, "1.5") <= 0 ? version : "1.5"),
1618 sprintf(vlog, "We claim version: %s", verstring);
1620 strcat(verstring, "\n");
1621 logevent("Using SSH protocol version 1");
1622 sk_write(s, verstring, strlen(verstring));
1623 ssh_protocol = ssh1_protocol;
1625 s_rdpkt = ssh1_rdpkt;
1627 ssh_state = SSH_STATE_BEFORE_SIZE;
1634 static void ssh_gotdata(unsigned char *data, int datalen)
1639 * To begin with, feed the characters one by one to the
1640 * protocol initialisation / selection function do_ssh_init().
1641 * When that returns 0, we're done with the initial greeting
1642 * exchange and can move on to packet discipline.
1647 crReturnV; /* more data please */
1648 ret = do_ssh_init(*data);
1656 * We emerge from that loop when the initial negotiation is
1657 * over and we have selected an s_rdpkt function. Now pass
1658 * everything to s_rdpkt, and then pass the resulting packets
1659 * to the proper protocol handler.
1664 while (datalen > 0) {
1665 if (s_rdpkt(&data, &datalen) == 0) {
1666 if (ssh_state == SSH_STATE_CLOSED) {
1669 ssh_protocol(NULL, 0, 1);
1670 if (ssh_state == SSH_STATE_CLOSED) {
1680 static int ssh_closing(Plug plug, char *error_msg, int error_code,
1683 ssh_state = SSH_STATE_CLOSED;
1689 /* A socket error has occurred. */
1690 connection_fatal(error_msg);
1692 /* Otherwise, the remote side closed the connection normally. */
1697 static int ssh_receive(Plug plug, int urgent, char *data, int len)
1699 ssh_gotdata(data, len);
1700 if (ssh_state == SSH_STATE_CLOSED) {
1710 static void ssh_sent(Plug plug, int bufsize)
1713 * If the send backlog on the SSH socket itself clears, we
1714 * should unthrottle the whole world if it was throttled.
1716 if (bufsize < SSH_MAX_BACKLOG)
1717 ssh_throttle_all(0, bufsize);
1721 * Connect to specified host and port.
1722 * Returns an error message, or NULL on success.
1723 * Also places the canonical host name into `realhost'. It must be
1724 * freed by the caller.
1726 static char *connect_to_host(char *host, int port, char **realhost, int nodelay)
1728 static struct plug_function_table fn_table = {
1733 }, *fn_table_ptr = &fn_table;
1742 savedhost = smalloc(1 + strlen(host));
1744 fatalbox("Out of memory");
1745 strcpy(savedhost, host);
1748 port = 22; /* default ssh port */
1763 sprintf(buf, "Looking up host \"%.170s\"", host);
1766 addr = sk_namelookup(host, realhost);
1767 if ((err = sk_addr_error(addr)))
1771 *realhost = strdup(FWhost);
1778 char buf[200], addrbuf[100];
1779 sk_getaddr(addr, addrbuf, 100);
1780 sprintf(buf, "Connecting to %.100s port %d", addrbuf, port);
1783 s = sk_new(addr, port, 0, 1, nodelay, &fn_table_ptr);
1784 if ((err = sk_socket_error(s)))
1788 sk_write(s, "connect ", 8);
1789 sk_write(s, FWhost, strlen(FWhost));
1792 sprintf(buf, " %d\n", FWport);
1793 sk_write(s, buf, strlen(buf));
1801 * Throttle or unthrottle the SSH connection.
1803 static void ssh1_throttle(int adjust)
1805 int old_count = ssh1_throttle_count;
1806 ssh1_throttle_count += adjust;
1807 assert(ssh1_throttle_count >= 0);
1808 if (ssh1_throttle_count && !old_count) {
1809 sk_set_frozen(s, 1);
1810 } else if (!ssh1_throttle_count && old_count) {
1811 sk_set_frozen(s, 0);
1816 * Throttle or unthrottle _all_ local data streams (for when sends
1817 * on the SSH connection itself back up).
1819 static void ssh_throttle_all(int enable, int bufsize)
1822 struct ssh_channel *c;
1824 if (enable == ssh_throttled_all)
1826 ssh_throttled_all = enable;
1827 ssh_overall_bufsize = bufsize;
1830 for (i = 0; NULL != (c = index234(ssh_channels, i)); i++) {
1832 case CHAN_MAINSESSION:
1834 * This is treated separately, outside the switch.
1838 x11_override_throttle(c->u.x11.s, enable);
1841 /* Agent channels require no buffer management. */
1844 pfd_override_throttle(c->u.x11.s, enable);
1851 * Handle the key exchange and user authentication phases.
1853 static int do_ssh1_login(unsigned char *in, int inlen, int ispkt)
1857 static unsigned char *rsabuf, *keystr1, *keystr2;
1858 unsigned char cookie[8];
1859 struct RSAKey servkey, hostkey;
1860 struct MD5Context md5c;
1861 static unsigned long supported_ciphers_mask, supported_auths_mask;
1862 static int tried_publickey, tried_agent;
1863 static int tis_auth_refused, ccard_auth_refused;
1864 static unsigned char session_id[16];
1865 static int cipher_type;
1866 static char username[100];
1867 static void *publickey_blob;
1868 int publickey_bloblen;
1875 if (pktin.type != SSH1_SMSG_PUBLIC_KEY) {
1876 bombout(("Public key packet not received"));
1880 logevent("Received public keys");
1882 memcpy(cookie, pktin.body, 8);
1884 i = makekey(pktin.body + 8, &servkey, &keystr1, 0);
1885 j = makekey(pktin.body + 8 + i, &hostkey, &keystr2, 0);
1888 * Log the host key fingerprint.
1892 logevent("Host key fingerprint is:");
1893 strcpy(logmsg, " ");
1894 hostkey.comment = NULL;
1895 rsa_fingerprint(logmsg + strlen(logmsg),
1896 sizeof(logmsg) - strlen(logmsg), &hostkey);
1900 ssh1_remote_protoflags = GET_32BIT(pktin.body + 8 + i + j);
1901 supported_ciphers_mask = GET_32BIT(pktin.body + 12 + i + j);
1902 supported_auths_mask = GET_32BIT(pktin.body + 16 + i + j);
1904 ssh1_local_protoflags =
1905 ssh1_remote_protoflags & SSH1_PROTOFLAGS_SUPPORTED;
1906 ssh1_local_protoflags |= SSH1_PROTOFLAG_SCREEN_NUMBER;
1909 MD5Update(&md5c, keystr2, hostkey.bytes);
1910 MD5Update(&md5c, keystr1, servkey.bytes);
1911 MD5Update(&md5c, pktin.body, 8);
1912 MD5Final(session_id, &md5c);
1914 for (i = 0; i < 32; i++)
1915 session_key[i] = random_byte();
1917 len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes);
1919 rsabuf = smalloc(len);
1921 fatalbox("Out of memory");
1924 * Verify the host key.
1928 * First format the key into a string.
1930 int len = rsastr_len(&hostkey);
1931 char fingerprint[100];
1932 char *keystr = smalloc(len);
1934 fatalbox("Out of memory");
1935 rsastr_fmt(keystr, &hostkey);
1936 rsa_fingerprint(fingerprint, sizeof(fingerprint), &hostkey);
1937 verify_ssh_host_key(savedhost, savedport, "rsa", keystr,
1942 for (i = 0; i < 32; i++) {
1943 rsabuf[i] = session_key[i];
1945 rsabuf[i] ^= session_id[i];
1948 if (hostkey.bytes > servkey.bytes) {
1949 rsaencrypt(rsabuf, 32, &servkey);
1950 rsaencrypt(rsabuf, servkey.bytes, &hostkey);
1952 rsaencrypt(rsabuf, 32, &hostkey);
1953 rsaencrypt(rsabuf, hostkey.bytes, &servkey);
1956 logevent("Encrypted session key");
1959 int cipher_chosen = 0, warn = 0;
1960 char *cipher_string = NULL;
1961 for (i = 0; !cipher_chosen && i < CIPHER_MAX; i++) {
1962 int next_cipher = cfg.ssh_cipherlist[i];
1963 if (next_cipher == CIPHER_WARN) {
1964 /* If/when we choose a cipher, warn about it */
1966 } else if (next_cipher == CIPHER_AES) {
1967 /* XXX Probably don't need to mention this. */
1968 logevent("AES not supported in SSH1, skipping");
1970 switch (next_cipher) {
1971 case CIPHER_3DES: cipher_type = SSH_CIPHER_3DES;
1972 cipher_string = "3DES"; break;
1973 case CIPHER_BLOWFISH: cipher_type = SSH_CIPHER_BLOWFISH;
1974 cipher_string = "Blowfish"; break;
1975 case CIPHER_DES: cipher_type = SSH_CIPHER_DES;
1976 cipher_string = "single-DES"; break;
1978 if (supported_ciphers_mask & (1 << cipher_type))
1982 if (!cipher_chosen) {
1983 if ((supported_ciphers_mask & (1 << SSH_CIPHER_3DES)) == 0)
1984 bombout(("Server violates SSH 1 protocol by not "
1985 "supporting 3DES encryption"));
1987 /* shouldn't happen */
1988 bombout(("No supported ciphers found"));
1992 /* Warn about chosen cipher if necessary. */
1994 askcipher(cipher_string, 0);
1997 switch (cipher_type) {
1998 case SSH_CIPHER_3DES:
1999 logevent("Using 3DES encryption");
2001 case SSH_CIPHER_DES:
2002 logevent("Using single-DES encryption");
2004 case SSH_CIPHER_BLOWFISH:
2005 logevent("Using Blowfish encryption");
2009 send_packet(SSH1_CMSG_SESSION_KEY,
2010 PKT_CHAR, cipher_type,
2011 PKT_DATA, cookie, 8,
2012 PKT_CHAR, (len * 8) >> 8, PKT_CHAR, (len * 8) & 0xFF,
2013 PKT_DATA, rsabuf, len,
2014 PKT_INT, ssh1_local_protoflags, PKT_END);
2016 logevent("Trying to enable encryption...");
2020 cipher = cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 :
2021 cipher_type == SSH_CIPHER_DES ? &ssh_des : &ssh_3des;
2022 cipher->sesskey(session_key);
2026 if (pktin.type != SSH1_SMSG_SUCCESS) {
2027 bombout(("Encryption not successfully enabled"));
2031 logevent("Successfully started encryption");
2037 if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
2039 if (!ssh_get_line("login as: ",
2040 username, sizeof(username), FALSE)) {
2042 * get_line failed to get a username.
2045 logevent("No username provided. Abandoning session.");
2046 ssh_state = SSH_STATE_CLOSED;
2050 c_write_str("login as: ");
2053 crWaitUntil(!ispkt);
2055 switch (c = *in++) {
2064 c_write_str("\b \b");
2071 c_write_str("\b \b");
2081 if (((c >= ' ' && c <= '~') ||
2082 ((unsigned char) c >= 160))
2083 && pos < sizeof(username)-1) {
2084 username[pos++] = c;
2090 c_write_str("\r\n");
2091 username[strcspn(username, "\n\r")] = '\0';
2094 strncpy(username, cfg.username, 99);
2095 username[99] = '\0';
2098 send_packet(SSH1_CMSG_USER, PKT_STR, username, PKT_END);
2100 char userlog[22 + sizeof(username)];
2101 sprintf(userlog, "Sent username \"%s\"", username);
2103 if (flags & FLAG_INTERACTIVE &&
2104 (!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) {
2105 strcat(userlog, "\r\n");
2106 c_write_str(userlog);
2113 tried_publickey = tried_agent = 0;
2114 tis_auth_refused = ccard_auth_refused = 0;
2115 /* Load the public half of cfg.keyfile so we notice if it's in Pageant */
2117 if (!rsakey_pubblob(cfg.keyfile, &publickey_blob, &publickey_bloblen))
2118 publickey_blob = NULL;
2120 publickey_blob = NULL;
2122 while (pktin.type == SSH1_SMSG_FAILURE) {
2123 static char password[100];
2124 static char prompt[200];
2127 static int pwpkt_type;
2128 pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
2130 if (agent_exists() && !tried_agent) {
2132 * Attempt RSA authentication using Pageant.
2134 static unsigned char request[5], *response, *p;
2135 static int responselen;
2136 static int i, nkeys;
2137 static int authed = FALSE;
2141 logevent("Pageant is running. Requesting keys.");
2143 /* Request the keys held by the agent. */
2144 PUT_32BIT(request, 1);
2145 request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES;
2146 agent_query(request, 5, &r, &responselen);
2147 response = (unsigned char *) r;
2148 if (response && responselen >= 5 &&
2149 response[4] == SSH1_AGENT_RSA_IDENTITIES_ANSWER) {
2151 nkeys = GET_32BIT(p);
2155 sprintf(buf, "Pageant has %d SSH1 keys", nkeys);
2158 for (i = 0; i < nkeys; i++) {
2159 static struct RSAKey key;
2160 static Bignum challenge;
2161 static char *commentp;
2162 static int commentlen;
2166 sprintf(buf, "Trying Pageant key #%d", i);
2169 if (publickey_blob &&
2170 !memcmp(p, publickey_blob, publickey_bloblen)) {
2171 logevent("This key matches configured key file");
2172 tried_publickey = 1;
2175 p += ssh1_read_bignum(p, &key.exponent);
2176 p += ssh1_read_bignum(p, &key.modulus);
2177 commentlen = GET_32BIT(p);
2181 send_packet(SSH1_CMSG_AUTH_RSA,
2182 PKT_BIGNUM, key.modulus, PKT_END);
2184 if (pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
2185 logevent("Key refused");
2188 logevent("Received RSA challenge");
2189 ssh1_read_bignum(pktin.body, &challenge);
2191 char *agentreq, *q, *ret;
2194 len = 1 + 4; /* message type, bit count */
2195 len += ssh1_bignum_length(key.exponent);
2196 len += ssh1_bignum_length(key.modulus);
2197 len += ssh1_bignum_length(challenge);
2198 len += 16; /* session id */
2199 len += 4; /* response format */
2200 agentreq = smalloc(4 + len);
2201 PUT_32BIT(agentreq, len);
2203 *q++ = SSH1_AGENTC_RSA_CHALLENGE;
2204 PUT_32BIT(q, bignum_bitcount(key.modulus));
2206 q += ssh1_write_bignum(q, key.exponent);
2207 q += ssh1_write_bignum(q, key.modulus);
2208 q += ssh1_write_bignum(q, challenge);
2209 memcpy(q, session_id, 16);
2211 PUT_32BIT(q, 1); /* response format */
2212 agent_query(agentreq, len + 4, &vret, &retlen);
2216 if (ret[4] == SSH1_AGENT_RSA_RESPONSE) {
2217 logevent("Sending Pageant's response");
2218 send_packet(SSH1_CMSG_AUTH_RSA_RESPONSE,
2219 PKT_DATA, ret + 5, 16,
2223 if (pktin.type == SSH1_SMSG_SUCCESS) {
2225 ("Pageant's response accepted");
2226 if (flags & FLAG_VERBOSE) {
2228 ("Authenticated using RSA key \"");
2229 c_write(commentp, commentlen);
2230 c_write_str("\" from agent\r\n");
2235 ("Pageant's response not accepted");
2238 ("Pageant failed to answer challenge");
2242 logevent("No reply received from Pageant");
2245 freebn(key.exponent);
2246 freebn(key.modulus);
2255 if (*cfg.keyfile && !tried_publickey)
2256 pwpkt_type = SSH1_CMSG_AUTH_RSA;
2258 if (cfg.try_tis_auth &&
2259 (supported_auths_mask & (1 << SSH1_AUTH_TIS)) &&
2260 !tis_auth_refused) {
2261 pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
2262 logevent("Requested TIS authentication");
2263 send_packet(SSH1_CMSG_AUTH_TIS, PKT_END);
2265 if (pktin.type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
2266 logevent("TIS authentication declined");
2267 if (flags & FLAG_INTERACTIVE)
2268 c_write_str("TIS authentication refused.\r\n");
2269 tis_auth_refused = 1;
2272 int challengelen = ((pktin.body[0] << 24) |
2273 (pktin.body[1] << 16) |
2274 (pktin.body[2] << 8) |
2276 logevent("Received TIS challenge");
2277 if (challengelen > sizeof(prompt) - 1)
2278 challengelen = sizeof(prompt) - 1; /* prevent overrun */
2279 memcpy(prompt, pktin.body + 4, challengelen);
2280 /* Prompt heuristic comes from OpenSSH */
2281 strncpy(prompt + challengelen,
2282 memchr(prompt, '\n', challengelen) ?
2283 "": "\r\nResponse: ",
2284 (sizeof prompt) - challengelen);
2285 prompt[(sizeof prompt) - 1] = '\0';
2288 if (cfg.try_tis_auth &&
2289 (supported_auths_mask & (1 << SSH1_AUTH_CCARD)) &&
2290 !ccard_auth_refused) {
2291 pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE;
2292 logevent("Requested CryptoCard authentication");
2293 send_packet(SSH1_CMSG_AUTH_CCARD, PKT_END);
2295 if (pktin.type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
2296 logevent("CryptoCard authentication declined");
2297 c_write_str("CryptoCard authentication refused.\r\n");
2298 ccard_auth_refused = 1;
2301 int challengelen = ((pktin.body[0] << 24) |
2302 (pktin.body[1] << 16) |
2303 (pktin.body[2] << 8) |
2305 logevent("Received CryptoCard challenge");
2306 if (challengelen > sizeof(prompt) - 1)
2307 challengelen = sizeof(prompt) - 1; /* prevent overrun */
2308 memcpy(prompt, pktin.body + 4, challengelen);
2309 strncpy(prompt + challengelen,
2310 memchr(prompt, '\n', challengelen) ?
2311 "" : "\r\nResponse: ",
2312 sizeof(prompt) - challengelen);
2313 prompt[sizeof(prompt) - 1] = '\0';
2316 if (pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
2317 sprintf(prompt, "%.90s@%.90s's password: ",
2318 username, savedhost);
2320 if (pwpkt_type == SSH1_CMSG_AUTH_RSA) {
2321 char *comment = NULL;
2322 if (flags & FLAG_VERBOSE)
2323 c_write_str("Trying public key authentication.\r\n");
2324 if (!rsakey_encrypted(cfg.keyfile, &comment)) {
2325 if (flags & FLAG_VERBOSE)
2326 c_write_str("No passphrase required.\r\n");
2329 sprintf(prompt, "Passphrase for key \"%.100s\": ", comment);
2334 * Show password prompt, having first obtained it via a TIS
2335 * or CryptoCard exchange if we're doing TIS or CryptoCard
2339 if (!ssh_get_line(prompt, password, sizeof(password), TRUE)) {
2341 * get_line failed to get a password (for example
2342 * because one was supplied on the command line
2343 * which has already failed to work). Terminate.
2345 send_packet(SSH1_MSG_DISCONNECT,
2346 PKT_STR, "No more passwords available to try",
2348 connection_fatal("Unable to authenticate");
2349 ssh_state = SSH_STATE_CLOSED;
2353 /* Prompt may have come from server. We've munged it a bit, so
2354 * we know it to be zero-terminated at least once. */
2355 c_write_untrusted(prompt, strlen(prompt));
2359 crWaitUntil(!ispkt);
2361 switch (c = *in++) {
2382 if (pos < sizeof(password)-1)
2383 password[pos++] = c;
2387 c_write_str("\r\n");
2391 if (pwpkt_type == SSH1_CMSG_AUTH_RSA) {
2393 * Try public key authentication with the specified
2396 static struct RSAKey pubkey;
2397 static Bignum challenge, response;
2399 static unsigned char buffer[32];
2401 tried_publickey = 1;
2402 i = loadrsakey(cfg.keyfile, &pubkey, password);
2404 c_write_str("Couldn't load private key from ");
2405 c_write_str(cfg.keyfile);
2406 c_write_str(".\r\n");
2407 continue; /* go and try password */
2410 c_write_str("Wrong passphrase.\r\n");
2411 tried_publickey = 0;
2412 continue; /* try again */
2416 * Send a public key attempt.
2418 send_packet(SSH1_CMSG_AUTH_RSA,
2419 PKT_BIGNUM, pubkey.modulus, PKT_END);
2422 if (pktin.type == SSH1_SMSG_FAILURE) {
2423 c_write_str("Server refused our public key.\r\n");
2424 continue; /* go and try password */
2426 if (pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
2427 bombout(("Bizarre response to offer of public key"));
2430 ssh1_read_bignum(pktin.body, &challenge);
2431 response = rsadecrypt(challenge, &pubkey);
2432 freebn(pubkey.private_exponent); /* burn the evidence */
2434 for (i = 0; i < 32; i++) {
2435 buffer[i] = bignum_byte(response, 31 - i);
2439 MD5Update(&md5c, buffer, 32);
2440 MD5Update(&md5c, session_id, 16);
2441 MD5Final(buffer, &md5c);
2443 send_packet(SSH1_CMSG_AUTH_RSA_RESPONSE,
2444 PKT_DATA, buffer, 16, PKT_END);
2447 if (pktin.type == SSH1_SMSG_FAILURE) {
2448 if (flags & FLAG_VERBOSE)
2450 ("Failed to authenticate with our public key.\r\n");
2451 continue; /* go and try password */
2452 } else if (pktin.type != SSH1_SMSG_SUCCESS) {
2454 ("Bizarre response to RSA authentication response"));
2458 break; /* we're through! */
2460 if (pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
2462 * Defence against traffic analysis: we send a
2463 * whole bunch of packets containing strings of
2464 * different lengths. One of these strings is the
2465 * password, in a SSH1_CMSG_AUTH_PASSWORD packet.
2466 * The others are all random data in
2467 * SSH1_MSG_IGNORE packets. This way a passive
2468 * listener can't tell which is the password, and
2469 * hence can't deduce the password length.
2471 * Anybody with a password length greater than 16
2472 * bytes is going to have enough entropy in their
2473 * password that a listener won't find it _that_
2474 * much help to know how long it is. So what we'll
2477 * - if password length < 16, we send 15 packets
2478 * containing string lengths 1 through 15
2480 * - otherwise, we let N be the nearest multiple
2481 * of 8 below the password length, and send 8
2482 * packets containing string lengths N through
2483 * N+7. This won't obscure the order of
2484 * magnitude of the password length, but it will
2485 * introduce a bit of extra uncertainty.
2487 * A few servers (the old 1.2.18 through 1.2.22)
2488 * can't deal with SSH1_MSG_IGNORE. For these
2489 * servers, we need an alternative defence. We make
2490 * use of the fact that the password is interpreted
2491 * as a C string: so we can append a NUL, then some
2494 * One server (a Cisco one) can deal with neither
2495 * SSH1_MSG_IGNORE _nor_ a padded password string.
2496 * For this server we are left with no defences
2497 * against password length sniffing.
2499 if (!(ssh_remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE)) {
2501 * The server can deal with SSH1_MSG_IGNORE, so
2502 * we can use the primary defence.
2504 int bottom, top, pwlen, i;
2507 pwlen = strlen(password);
2509 bottom = 0; /* zero length passwords are OK! :-) */
2512 bottom = pwlen & ~7;
2516 assert(pwlen >= bottom && pwlen <= top);
2518 randomstr = smalloc(top + 1);
2520 for (i = bottom; i <= top; i++) {
2522 defer_packet(pwpkt_type, PKT_STR, password,
2525 for (j = 0; j < i; j++) {
2527 randomstr[j] = random_byte();
2528 } while (randomstr[j] == '\0');
2530 randomstr[i] = '\0';
2531 defer_packet(SSH1_MSG_IGNORE,
2532 PKT_STR, randomstr, PKT_END);
2535 logevent("Sending password with camouflage packets");
2536 ssh_pkt_defersend();
2538 else if (!(ssh_remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) {
2540 * The server can't deal with SSH1_MSG_IGNORE
2541 * but can deal with padded passwords, so we
2542 * can use the secondary defence.
2548 len = strlen(password);
2549 if (len < sizeof(string)) {
2551 strcpy(string, password);
2552 len++; /* cover the zero byte */
2553 while (len < sizeof(string)) {
2554 string[len++] = (char) random_byte();
2559 logevent("Sending length-padded password");
2560 send_packet(pwpkt_type, PKT_INT, len,
2561 PKT_DATA, s, len, PKT_END);
2564 * The server has _both_
2565 * BUG_CHOKES_ON_SSH1_IGNORE and
2566 * BUG_NEEDS_SSH1_PLAIN_PASSWORD. There is
2567 * therefore nothing we can do.
2570 len = strlen(password);
2571 logevent("Sending unpadded password");
2572 send_packet(pwpkt_type, PKT_INT, len,
2573 PKT_DATA, password, len, PKT_END);
2576 send_packet(pwpkt_type, PKT_STR, password, PKT_END);
2579 logevent("Sent password");
2580 memset(password, 0, strlen(password));
2582 if (pktin.type == SSH1_SMSG_FAILURE) {
2583 if (flags & FLAG_VERBOSE)
2584 c_write_str("Access denied\r\n");
2585 logevent("Authentication refused");
2586 } else if (pktin.type == SSH1_MSG_DISCONNECT) {
2587 logevent("Received disconnect request");
2588 ssh_state = SSH_STATE_CLOSED;
2590 } else if (pktin.type != SSH1_SMSG_SUCCESS) {
2591 bombout(("Strange packet received, type %d", pktin.type));
2596 logevent("Authentication successful");
2601 void sshfwd_close(struct ssh_channel *c)
2603 if (c && !c->closes) {
2605 * If the channel's remoteid is -1, we have sent
2606 * CHANNEL_OPEN for this channel, but it hasn't even been
2607 * acknowledged by the server. So we must set a close flag
2608 * on it now, and then when the server acks the channel
2609 * open, we can close it then.
2611 if (c->remoteid != -1) {
2612 if (ssh_version == 1) {
2613 send_packet(SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid,
2616 ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE);
2617 ssh2_pkt_adduint32(c->remoteid);
2622 if (c->type == CHAN_X11) {
2624 logevent("Forwarded X11 connection terminated");
2625 } else if (c->type == CHAN_SOCKDATA ||
2626 c->type == CHAN_SOCKDATA_DORMANT) {
2628 logevent("Forwarded port closed");
2633 int sshfwd_write(struct ssh_channel *c, char *buf, int len)
2635 if (ssh_version == 1) {
2636 send_packet(SSH1_MSG_CHANNEL_DATA,
2637 PKT_INT, c->remoteid,
2638 PKT_INT, len, PKT_DATA, buf, len, PKT_END);
2640 * In SSH1 we can return 0 here - implying that forwarded
2641 * connections are never individually throttled - because
2642 * the only circumstance that can cause throttling will be
2643 * the whole SSH connection backing up, in which case
2644 * _everything_ will be throttled as a whole.
2648 ssh2_add_channel_data(c, buf, len);
2649 return ssh2_try_send(c);
2653 void sshfwd_unthrottle(struct ssh_channel *c, int bufsize)
2655 if (ssh_version == 1) {
2656 if (c->v.v1.throttling && bufsize < SSH1_BUFFER_LIMIT) {
2657 c->v.v1.throttling = 0;
2661 ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
2665 static void ssh1_protocol(unsigned char *in, int inlen, int ispkt)
2671 while (!do_ssh1_login(in, inlen, ispkt)) {
2674 if (ssh_state == SSH_STATE_CLOSED)
2677 if (cfg.agentfwd && agent_exists()) {
2678 logevent("Requesting agent forwarding");
2679 send_packet(SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END);
2683 if (pktin.type != SSH1_SMSG_SUCCESS
2684 && pktin.type != SSH1_SMSG_FAILURE) {
2685 bombout(("Protocol confusion"));
2687 } else if (pktin.type == SSH1_SMSG_FAILURE) {
2688 logevent("Agent forwarding refused");
2690 logevent("Agent forwarding enabled");
2691 ssh_agentfwd_enabled = TRUE;
2695 if (cfg.x11_forward) {
2696 char proto[20], data[64];
2697 logevent("Requesting X11 forwarding");
2698 x11_invent_auth(proto, sizeof(proto), data, sizeof(data));
2699 if (ssh1_local_protoflags & SSH1_PROTOFLAG_SCREEN_NUMBER) {
2700 send_packet(SSH1_CMSG_X11_REQUEST_FORWARDING,
2701 PKT_STR, proto, PKT_STR, data,
2702 PKT_INT, 0, PKT_END);
2704 send_packet(SSH1_CMSG_X11_REQUEST_FORWARDING,
2705 PKT_STR, proto, PKT_STR, data, PKT_END);
2710 if (pktin.type != SSH1_SMSG_SUCCESS
2711 && pktin.type != SSH1_SMSG_FAILURE) {
2712 bombout(("Protocol confusion"));
2714 } else if (pktin.type == SSH1_SMSG_FAILURE) {
2715 logevent("X11 forwarding refused");
2717 logevent("X11 forwarding enabled");
2718 ssh_X11_fwd_enabled = TRUE;
2726 char sports[256], dports[256], host[256];
2729 ssh_rportfwds = newtree234(ssh_rportcmp_ssh1);
2730 /* Add port forwardings. */
2735 while (*e && *e != '\t')
2741 while (*e && *e != ':')
2751 dport = atoi(dports);
2752 sport = atoi(sports);
2753 if (sport && dport) {
2755 pfd_addforward(host, dport, sport);
2756 sprintf(buf, "Local port %d forwarding to %s:%d",
2757 sport, host, dport);
2760 struct ssh_rportfwd *pf;
2761 pf = smalloc(sizeof(*pf));
2762 strcpy(pf->dhost, host);
2764 if (add234(ssh_rportfwds, pf) != pf) {
2766 "Duplicate remote port forwarding to %s:%d",
2771 sprintf(buf, "Requesting remote port %d forward to %s:%d",
2772 sport, host, dport);
2774 send_packet(SSH1_CMSG_PORT_FORWARD_REQUEST,
2786 send_packet(SSH1_CMSG_REQUEST_PTY,
2787 PKT_STR, cfg.termtype,
2788 PKT_INT, rows, PKT_INT, cols,
2789 PKT_INT, 0, PKT_INT, 0, PKT_CHAR, 0, PKT_END);
2790 ssh_state = SSH_STATE_INTERMED;
2794 if (pktin.type != SSH1_SMSG_SUCCESS
2795 && pktin.type != SSH1_SMSG_FAILURE) {
2796 bombout(("Protocol confusion"));
2798 } else if (pktin.type == SSH1_SMSG_FAILURE) {
2799 c_write_str("Server refused to allocate pty\r\n");
2800 ssh_editing = ssh_echoing = 1;
2802 logevent("Allocated pty");
2804 ssh_editing = ssh_echoing = 1;
2807 if (cfg.compression) {
2808 send_packet(SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END);
2812 if (pktin.type != SSH1_SMSG_SUCCESS
2813 && pktin.type != SSH1_SMSG_FAILURE) {
2814 bombout(("Protocol confusion"));
2816 } else if (pktin.type == SSH1_SMSG_FAILURE) {
2817 c_write_str("Server refused to compress\r\n");
2819 logevent("Started compression");
2820 ssh1_compressing = TRUE;
2821 zlib_compress_init();
2822 zlib_decompress_init();
2826 * Start the shell or command.
2828 * Special case: if the first-choice command is an SSH2
2829 * subsystem (hence not usable here) and the second choice
2830 * exists, we fall straight back to that.
2833 char *cmd = cfg.remote_cmd_ptr;
2835 if (cfg.ssh_subsys && cfg.remote_cmd_ptr2) {
2836 cmd = cfg.remote_cmd_ptr2;
2837 ssh_fallback_cmd = TRUE;
2840 send_packet(SSH1_CMSG_EXEC_CMD, PKT_STR, cmd, PKT_END);
2842 send_packet(SSH1_CMSG_EXEC_SHELL, PKT_END);
2843 logevent("Started session");
2846 ssh_state = SSH_STATE_SESSION;
2850 ssh_special(TS_EOF);
2852 ldisc_send(NULL, 0, 0); /* cause ldisc to notice changes */
2854 ssh_channels = newtree234(ssh_channelcmp);
2858 if (pktin.type == SSH1_SMSG_STDOUT_DATA ||
2859 pktin.type == SSH1_SMSG_STDERR_DATA) {
2860 long len = GET_32BIT(pktin.body);
2862 from_backend(pktin.type == SSH1_SMSG_STDERR_DATA,
2863 pktin.body + 4, len);
2864 if (!ssh1_stdout_throttling && bufsize > SSH1_BUFFER_LIMIT) {
2865 ssh1_stdout_throttling = 1;
2868 } else if (pktin.type == SSH1_MSG_DISCONNECT) {
2869 ssh_state = SSH_STATE_CLOSED;
2870 logevent("Received disconnect request");
2872 } else if (pktin.type == SSH1_SMSG_X11_OPEN) {
2873 /* Remote side is trying to open a channel to talk to our
2874 * X-Server. Give them back a local channel number. */
2875 struct ssh_channel *c;
2877 logevent("Received X11 connect request");
2878 /* Refuse if X11 forwarding is disabled. */
2879 if (!ssh_X11_fwd_enabled) {
2880 send_packet(SSH1_MSG_CHANNEL_OPEN_FAILURE,
2881 PKT_INT, GET_32BIT(pktin.body), PKT_END);
2882 logevent("Rejected X11 connect request");
2884 c = smalloc(sizeof(struct ssh_channel));
2886 if (x11_init(&c->u.x11.s, cfg.x11_display, c) != NULL) {
2887 logevent("opening X11 forward connection failed");
2889 send_packet(SSH1_MSG_CHANNEL_OPEN_FAILURE,
2890 PKT_INT, GET_32BIT(pktin.body),
2894 ("opening X11 forward connection succeeded");
2895 c->remoteid = GET_32BIT(pktin.body);
2896 c->localid = alloc_channel_id();
2898 c->v.v1.throttling = 0;
2899 c->type = CHAN_X11; /* identify channel type */
2900 add234(ssh_channels, c);
2901 send_packet(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
2902 PKT_INT, c->remoteid, PKT_INT,
2903 c->localid, PKT_END);
2904 logevent("Opened X11 forward channel");
2907 } else if (pktin.type == SSH1_SMSG_AGENT_OPEN) {
2908 /* Remote side is trying to open a channel to talk to our
2909 * agent. Give them back a local channel number. */
2910 struct ssh_channel *c;
2912 /* Refuse if agent forwarding is disabled. */
2913 if (!ssh_agentfwd_enabled) {
2914 send_packet(SSH1_MSG_CHANNEL_OPEN_FAILURE,
2915 PKT_INT, GET_32BIT(pktin.body), PKT_END);
2917 c = smalloc(sizeof(struct ssh_channel));
2918 c->remoteid = GET_32BIT(pktin.body);
2919 c->localid = alloc_channel_id();
2921 c->v.v1.throttling = 0;
2922 c->type = CHAN_AGENT; /* identify channel type */
2923 c->u.a.lensofar = 0;
2924 add234(ssh_channels, c);
2925 send_packet(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
2926 PKT_INT, c->remoteid, PKT_INT, c->localid,
2929 } else if (pktin.type == SSH1_MSG_PORT_OPEN) {
2930 /* Remote side is trying to open a channel to talk to a
2931 * forwarded port. Give them back a local channel number. */
2932 struct ssh_channel *c;
2933 struct ssh_rportfwd pf;
2935 char host[256], buf[1024];
2937 c = smalloc(sizeof(struct ssh_channel));
2939 hostsize = GET_32BIT(pktin.body+4);
2940 for(h = host, p = pktin.body+8; hostsize != 0; hostsize--) {
2941 if (h+1 < host+sizeof(host))
2946 port = GET_32BIT(p);
2948 strcpy(pf.dhost, host);
2951 if (find234(ssh_rportfwds, &pf, NULL) == NULL) {
2952 sprintf(buf, "Rejected remote port open request for %s:%d",
2955 send_packet(SSH1_MSG_CHANNEL_OPEN_FAILURE,
2956 PKT_INT, GET_32BIT(pktin.body), PKT_END);
2958 sprintf(buf, "Received remote port open request for %s:%d",
2961 e = pfd_newconnect(&c->u.pfd.s, host, port, c);
2964 sprintf(buf, "Port open failed: %s", e);
2967 send_packet(SSH1_MSG_CHANNEL_OPEN_FAILURE,
2968 PKT_INT, GET_32BIT(pktin.body),
2971 c->remoteid = GET_32BIT(pktin.body);
2972 c->localid = alloc_channel_id();
2974 c->v.v1.throttling = 0;
2975 c->type = CHAN_SOCKDATA; /* identify channel type */
2976 add234(ssh_channels, c);
2977 send_packet(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
2978 PKT_INT, c->remoteid, PKT_INT,
2979 c->localid, PKT_END);
2980 logevent("Forwarded port opened successfully");
2984 } else if (pktin.type == SSH1_MSG_CHANNEL_OPEN_CONFIRMATION) {
2985 unsigned int remoteid = GET_32BIT(pktin.body);
2986 unsigned int localid = GET_32BIT(pktin.body+4);
2987 struct ssh_channel *c;
2989 c = find234(ssh_channels, &remoteid, ssh_channelfind);
2990 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
2991 c->remoteid = localid;
2992 c->type = CHAN_SOCKDATA;
2993 c->v.v1.throttling = 0;
2994 pfd_confirm(c->u.pfd.s);
2997 if (c && c->closes) {
2999 * We have a pending close on this channel,
3000 * which we decided on before the server acked
3001 * the channel open. So now we know the
3002 * remoteid, we can close it again.
3004 send_packet(SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid,
3008 } else if (pktin.type == SSH1_MSG_CHANNEL_OPEN_FAILURE) {
3009 unsigned int remoteid = GET_32BIT(pktin.body);
3010 unsigned int localid = GET_32BIT(pktin.body+4);
3011 struct ssh_channel *c;
3013 c = find234(ssh_channels, &remoteid, ssh_channelfind);
3014 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
3015 logevent("Forwarded connection refused by server");
3016 pfd_close(c->u.pfd.s);
3017 del234(ssh_channels, c);
3021 } else if (pktin.type == SSH1_MSG_CHANNEL_CLOSE ||
3022 pktin.type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION) {
3023 /* Remote side closes a channel. */
3024 unsigned i = GET_32BIT(pktin.body);
3025 struct ssh_channel *c;
3026 c = find234(ssh_channels, &i, ssh_channelfind);
3030 (pktin.type == SSH1_MSG_CHANNEL_CLOSE ? 1 : 2);
3031 if (!(c->closes & closetype))
3032 send_packet(pktin.type, PKT_INT, c->remoteid,
3034 if ((c->closes == 0) && (c->type == CHAN_X11)) {
3035 logevent("Forwarded X11 connection terminated");
3036 assert(c->u.x11.s != NULL);
3037 x11_close(c->u.x11.s);
3040 if ((c->closes == 0) && (c->type == CHAN_SOCKDATA)) {
3041 logevent("Forwarded port closed");
3042 assert(c->u.pfd.s != NULL);
3043 pfd_close(c->u.pfd.s);
3046 c->closes |= closetype;
3047 if (c->closes == 3) {
3048 del234(ssh_channels, c);
3052 } else if (pktin.type == SSH1_MSG_CHANNEL_DATA) {
3053 /* Data sent down one of our channels. */
3054 int i = GET_32BIT(pktin.body);
3055 int len = GET_32BIT(pktin.body + 4);
3056 unsigned char *p = pktin.body + 8;
3057 struct ssh_channel *c;
3058 c = find234(ssh_channels, &i, ssh_channelfind);
3063 bufsize = x11_send(c->u.x11.s, p, len);
3066 bufsize = pfd_send(c->u.pfd.s, p, len);
3069 /* Data for an agent message. Buffer it. */
3071 if (c->u.a.lensofar < 4) {
3072 int l = min(4 - c->u.a.lensofar, len);
3073 memcpy(c->u.a.msglen + c->u.a.lensofar, p,
3077 c->u.a.lensofar += l;
3079 if (c->u.a.lensofar == 4) {
3081 4 + GET_32BIT(c->u.a.msglen);
3082 c->u.a.message = smalloc(c->u.a.totallen);
3083 memcpy(c->u.a.message, c->u.a.msglen, 4);
3085 if (c->u.a.lensofar >= 4 && len > 0) {
3087 min(c->u.a.totallen - c->u.a.lensofar,
3089 memcpy(c->u.a.message + c->u.a.lensofar, p,
3093 c->u.a.lensofar += l;
3095 if (c->u.a.lensofar == c->u.a.totallen) {
3096 void *reply, *sentreply;
3098 agent_query(c->u.a.message,
3099 c->u.a.totallen, &reply,
3104 /* Fake SSH_AGENT_FAILURE. */
3105 sentreply = "\0\0\0\1\5";
3108 send_packet(SSH1_MSG_CHANNEL_DATA,
3109 PKT_INT, c->remoteid,
3111 PKT_DATA, sentreply, replylen,
3115 sfree(c->u.a.message);
3116 c->u.a.lensofar = 0;
3119 bufsize = 0; /* agent channels never back up */
3122 if (!c->v.v1.throttling && bufsize > SSH1_BUFFER_LIMIT) {
3123 c->v.v1.throttling = 1;
3127 } else if (pktin.type == SSH1_SMSG_SUCCESS) {
3128 /* may be from EXEC_SHELL on some servers */
3129 } else if (pktin.type == SSH1_SMSG_FAILURE) {
3130 /* may be from EXEC_SHELL on some servers
3131 * if no pty is available or in other odd cases. Ignore */
3132 } else if (pktin.type == SSH1_SMSG_EXIT_STATUS) {
3134 ssh_exitcode = GET_32BIT(pktin.body);
3135 sprintf(buf, "Server sent command exit status %d",
3138 send_packet(SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
3140 * In case `helpful' firewalls or proxies tack
3141 * extra human-readable text on the end of the
3142 * session which we might mistake for another
3143 * encrypted packet, we close the session once
3144 * we've sent EXIT_CONFIRMATION.
3146 ssh_state = SSH_STATE_CLOSED;
3149 bombout(("Strange packet received: type %d", pktin.type));
3154 int len = min(inlen, 512);
3155 send_packet(SSH1_CMSG_STDIN_DATA,
3156 PKT_INT, len, PKT_DATA, in, len, PKT_END);
3167 * Utility routine for decoding comma-separated strings in KEXINIT.
3169 static int in_commasep_string(char *needle, char *haystack, int haylen)
3171 int needlen = strlen(needle);
3174 * Is it at the start of the string?
3176 if (haylen >= needlen && /* haystack is long enough */
3177 !memcmp(needle, haystack, needlen) && /* initial match */
3178 (haylen == needlen || haystack[needlen] == ',')
3179 /* either , or EOS follows */
3183 * If not, search for the next comma and resume after that.
3184 * If no comma found, terminate.
3186 while (haylen > 0 && *haystack != ',')
3187 haylen--, haystack++;
3190 haylen--, haystack++; /* skip over comma itself */
3195 * SSH2 key creation method.
3197 static void ssh2_mkkey(Bignum K, char *H, char *sessid, char chr,
3201 /* First 20 bytes. */
3204 SHA_Bytes(&s, H, 20);
3205 SHA_Bytes(&s, &chr, 1);
3206 SHA_Bytes(&s, sessid, 20);
3207 SHA_Final(&s, keyspace);
3208 /* Next 20 bytes. */
3211 SHA_Bytes(&s, H, 20);
3212 SHA_Bytes(&s, keyspace, 20);
3213 SHA_Final(&s, keyspace + 20);
3217 * Handle the SSH2 transport layer.
3219 static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt)
3221 static int i, j, len, nbits, pbits, warn;
3223 static Bignum p, g, e, f, K;
3224 static int kex_init_value, kex_reply_value;
3225 static const struct ssh_mac **maclist;
3227 static const struct ssh2_cipher *cscipher_tobe = NULL;
3228 static const struct ssh2_cipher *sccipher_tobe = NULL;
3229 static const struct ssh_mac *csmac_tobe = NULL;
3230 static const struct ssh_mac *scmac_tobe = NULL;
3231 static const struct ssh_compress *cscomp_tobe = NULL;
3232 static const struct ssh_compress *sccomp_tobe = NULL;
3233 static char *hostkeydata, *sigdata, *keystr, *fingerprint;
3234 static int hostkeylen, siglen;
3235 static void *hkey; /* actual host key */
3236 static unsigned char exchange_hash[20];
3237 static unsigned char keyspace[40];
3238 static int n_preferred_ciphers;
3239 static const struct ssh2_ciphers *preferred_ciphers[CIPHER_MAX];
3240 static const struct ssh_compress *preferred_comp;
3241 static int cipherstr_started;
3242 static int first_kex;
3249 * Set up the preferred ciphers. (NULL => warn below here)
3251 n_preferred_ciphers = 0;
3252 for (i = 0; i < CIPHER_MAX; i++) {
3253 switch (cfg.ssh_cipherlist[i]) {
3254 case CIPHER_BLOWFISH:
3255 preferred_ciphers[n_preferred_ciphers] = &ssh2_blowfish;
3256 n_preferred_ciphers++;
3259 if (cfg.ssh2_des_cbc) {
3260 preferred_ciphers[n_preferred_ciphers] = &ssh2_des;
3261 n_preferred_ciphers++;
3265 preferred_ciphers[n_preferred_ciphers] = &ssh2_3des;
3266 n_preferred_ciphers++;
3269 preferred_ciphers[n_preferred_ciphers] = &ssh2_aes;
3270 n_preferred_ciphers++;
3273 /* Flag for later. Don't bother if it's the last in
3275 if (i < CIPHER_MAX - 1) {
3276 preferred_ciphers[n_preferred_ciphers] = NULL;
3277 n_preferred_ciphers++;
3284 * Set up preferred compression.
3286 if (cfg.compression)
3287 preferred_comp = &ssh_zlib;
3289 preferred_comp = &ssh_comp_none;
3292 * Be prepared to work around the buggy MAC problem.
3294 if (cfg.buggymac || (ssh_remote_bugs & BUG_SSH2_HMAC))
3295 maclist = buggymacs, nmacs = lenof(buggymacs);
3297 maclist = macs, nmacs = lenof(macs);
3301 * Construct and send our key exchange packet.
3303 ssh2_pkt_init(SSH2_MSG_KEXINIT);
3304 for (i = 0; i < 16; i++)
3305 ssh2_pkt_addbyte((unsigned char) random_byte());
3306 /* List key exchange algorithms. */
3307 ssh2_pkt_addstring_start();
3308 for (i = 0; i < lenof(kex_algs); i++) {
3309 ssh2_pkt_addstring_str(kex_algs[i]->name);
3310 if (i < lenof(kex_algs) - 1)
3311 ssh2_pkt_addstring_str(",");
3313 /* List server host key algorithms. */
3314 ssh2_pkt_addstring_start();
3315 for (i = 0; i < lenof(hostkey_algs); i++) {
3316 ssh2_pkt_addstring_str(hostkey_algs[i]->name);
3317 if (i < lenof(hostkey_algs) - 1)
3318 ssh2_pkt_addstring_str(",");
3320 /* List client->server encryption algorithms. */
3321 ssh2_pkt_addstring_start();
3322 cipherstr_started = 0;
3323 for (i = 0; i < n_preferred_ciphers; i++) {
3324 const struct ssh2_ciphers *c = preferred_ciphers[i];
3325 if (!c) continue; /* warning flag */
3326 for (j = 0; j < c->nciphers; j++) {
3327 if (cipherstr_started)
3328 ssh2_pkt_addstring_str(",");
3329 ssh2_pkt_addstring_str(c->list[j]->name);
3330 cipherstr_started = 1;
3333 /* List server->client encryption algorithms. */
3334 ssh2_pkt_addstring_start();
3335 cipherstr_started = 0;
3336 for (i = 0; i < n_preferred_ciphers; i++) {
3337 const struct ssh2_ciphers *c = preferred_ciphers[i];
3338 if (!c) continue; /* warning flag */
3339 for (j = 0; j < c->nciphers; j++) {
3340 if (cipherstr_started)
3341 ssh2_pkt_addstring_str(",");
3342 ssh2_pkt_addstring_str(c->list[j]->name);
3343 cipherstr_started = 1;
3346 /* List client->server MAC algorithms. */
3347 ssh2_pkt_addstring_start();
3348 for (i = 0; i < nmacs; i++) {
3349 ssh2_pkt_addstring_str(maclist[i]->name);
3351 ssh2_pkt_addstring_str(",");
3353 /* List server->client MAC algorithms. */
3354 ssh2_pkt_addstring_start();
3355 for (i = 0; i < nmacs; i++) {
3356 ssh2_pkt_addstring_str(maclist[i]->name);
3358 ssh2_pkt_addstring_str(",");
3360 /* List client->server compression algorithms. */
3361 ssh2_pkt_addstring_start();
3362 for (i = 0; i < lenof(compressions) + 1; i++) {
3363 const struct ssh_compress *c =
3364 i == 0 ? preferred_comp : compressions[i - 1];
3365 ssh2_pkt_addstring_str(c->name);
3366 if (i < lenof(compressions))
3367 ssh2_pkt_addstring_str(",");
3369 /* List server->client compression algorithms. */
3370 ssh2_pkt_addstring_start();
3371 for (i = 0; i < lenof(compressions) + 1; i++) {
3372 const struct ssh_compress *c =
3373 i == 0 ? preferred_comp : compressions[i - 1];
3374 ssh2_pkt_addstring_str(c->name);
3375 if (i < lenof(compressions))
3376 ssh2_pkt_addstring_str(",");
3378 /* List client->server languages. Empty list. */
3379 ssh2_pkt_addstring_start();
3380 /* List server->client languages. Empty list. */
3381 ssh2_pkt_addstring_start();
3382 /* First KEX packet does _not_ follow, because we're not that brave. */
3383 ssh2_pkt_addbool(FALSE);
3385 ssh2_pkt_adduint32(0);
3387 exhash = exhashbase;
3388 sha_string(&exhash, pktout.data + 5, pktout.length - 5);
3394 sha_string(&exhash, pktin.data + 5, pktin.length - 5);
3397 * Now examine the other side's KEXINIT to see what we're up
3400 if (pktin.type != SSH2_MSG_KEXINIT) {
3401 bombout(("expected key exchange packet from server"));
3406 cscipher_tobe = NULL;
3407 sccipher_tobe = NULL;
3412 pktin.savedpos += 16; /* skip garbage cookie */
3413 ssh2_pkt_getstring(&str, &len); /* key exchange algorithms */
3414 for (i = 0; i < lenof(kex_algs); i++) {
3415 if (in_commasep_string(kex_algs[i]->name, str, len)) {
3420 ssh2_pkt_getstring(&str, &len); /* host key algorithms */
3421 for (i = 0; i < lenof(hostkey_algs); i++) {
3422 if (in_commasep_string(hostkey_algs[i]->name, str, len)) {
3423 hostkey = hostkey_algs[i];
3427 ssh2_pkt_getstring(&str, &len); /* client->server cipher */
3429 for (i = 0; i < n_preferred_ciphers; i++) {
3430 const struct ssh2_ciphers *c = preferred_ciphers[i];
3434 for (j = 0; j < c->nciphers; j++) {
3435 if (in_commasep_string(c->list[j]->name, str, len)) {
3436 cscipher_tobe = c->list[j];
3441 if (cscipher_tobe) {
3443 askcipher(cscipher_tobe->name, 1);
3447 if (!cscipher_tobe) {
3448 bombout(("Couldn't agree a client-to-server cipher (available: %s)", str));
3452 ssh2_pkt_getstring(&str, &len); /* server->client cipher */
3454 for (i = 0; i < n_preferred_ciphers; i++) {
3455 const struct ssh2_ciphers *c = preferred_ciphers[i];
3459 for (j = 0; j < c->nciphers; j++) {
3460 if (in_commasep_string(c->list[j]->name, str, len)) {
3461 sccipher_tobe = c->list[j];
3466 if (sccipher_tobe) {
3468 askcipher(sccipher_tobe->name, 2);
3472 if (!sccipher_tobe) {
3473 bombout(("Couldn't agree a server-to-client cipher (available: %s)", str));
3477 ssh2_pkt_getstring(&str, &len); /* client->server mac */
3478 for (i = 0; i < nmacs; i++) {
3479 if (in_commasep_string(maclist[i]->name, str, len)) {
3480 csmac_tobe = maclist[i];
3484 ssh2_pkt_getstring(&str, &len); /* server->client mac */
3485 for (i = 0; i < nmacs; i++) {
3486 if (in_commasep_string(maclist[i]->name, str, len)) {
3487 scmac_tobe = maclist[i];
3491 ssh2_pkt_getstring(&str, &len); /* client->server compression */
3492 for (i = 0; i < lenof(compressions) + 1; i++) {
3493 const struct ssh_compress *c =
3494 i == 0 ? preferred_comp : compressions[i - 1];
3495 if (in_commasep_string(c->name, str, len)) {
3500 ssh2_pkt_getstring(&str, &len); /* server->client compression */
3501 for (i = 0; i < lenof(compressions) + 1; i++) {
3502 const struct ssh_compress *c =
3503 i == 0 ? preferred_comp : compressions[i - 1];
3504 if (in_commasep_string(c->name, str, len)) {
3511 * Work out the number of bits of key we will need from the key
3512 * exchange. We start with the maximum key length of either
3518 csbits = cscipher_tobe->keylen;
3519 scbits = sccipher_tobe->keylen;
3520 nbits = (csbits > scbits ? csbits : scbits);
3522 /* The keys only have 160-bit entropy, since they're based on
3523 * a SHA-1 hash. So cap the key size at 160 bits. */
3528 * If we're doing Diffie-Hellman group exchange, start by
3529 * requesting a group.
3531 if (kex == &ssh_diffiehellman_gex) {
3532 logevent("Doing Diffie-Hellman group exchange");
3533 ssh_pkt_ctx |= SSH2_PKTCTX_DHGEX;
3535 * Work out how big a DH group we will need to allow that
3538 pbits = 512 << ((nbits - 1) / 64);
3539 ssh2_pkt_init(SSH2_MSG_KEX_DH_GEX_REQUEST);
3540 ssh2_pkt_adduint32(pbits);
3544 if (pktin.type != SSH2_MSG_KEX_DH_GEX_GROUP) {
3545 bombout(("expected key exchange group packet from server"));
3548 p = ssh2_pkt_getmp();
3549 g = ssh2_pkt_getmp();
3550 dh_setup_group(p, g);
3551 kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT;
3552 kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY;
3554 ssh_pkt_ctx |= SSH2_PKTCTX_DHGROUP1;
3556 kex_init_value = SSH2_MSG_KEXDH_INIT;
3557 kex_reply_value = SSH2_MSG_KEXDH_REPLY;
3560 logevent("Doing Diffie-Hellman key exchange");
3562 * Now generate and send e for Diffie-Hellman.
3564 e = dh_create_e(nbits * 2);
3565 ssh2_pkt_init(kex_init_value);
3570 if (pktin.type != kex_reply_value) {
3571 bombout(("expected key exchange reply packet from server"));
3574 ssh2_pkt_getstring(&hostkeydata, &hostkeylen);
3575 f = ssh2_pkt_getmp();
3576 ssh2_pkt_getstring(&sigdata, &siglen);
3580 sha_string(&exhash, hostkeydata, hostkeylen);
3581 if (kex == &ssh_diffiehellman_gex) {
3582 sha_uint32(&exhash, pbits);
3583 sha_mpint(&exhash, p);
3584 sha_mpint(&exhash, g);
3586 sha_mpint(&exhash, e);
3587 sha_mpint(&exhash, f);
3588 sha_mpint(&exhash, K);
3589 SHA_Final(&exhash, exchange_hash);
3594 debug(("Exchange hash is:\n"));
3595 dmemdump(exchange_hash, 20);
3598 hkey = hostkey->newkey(hostkeydata, hostkeylen);
3600 !hostkey->verifysig(hkey, sigdata, siglen, exchange_hash, 20)) {
3601 bombout(("Server's host key did not match the signature supplied"));
3606 * Authenticate remote host: verify host key. (We've already
3607 * checked the signature of the exchange hash.)
3609 keystr = hostkey->fmtkey(hkey);
3610 fingerprint = hostkey->fingerprint(hkey);
3611 verify_ssh_host_key(savedhost, savedport, hostkey->keytype,
3612 keystr, fingerprint);
3613 if (first_kex) { /* don't bother logging this in rekeys */
3614 logevent("Host key fingerprint is:");
3615 logevent(fingerprint);
3619 hostkey->freekey(hkey);
3622 * Send SSH2_MSG_NEWKEYS.
3624 ssh2_pkt_init(SSH2_MSG_NEWKEYS);
3628 * Expect SSH2_MSG_NEWKEYS from server.
3631 if (pktin.type != SSH2_MSG_NEWKEYS) {
3632 bombout(("expected new-keys packet from server"));
3637 * Create and initialise session keys.
3639 cscipher = cscipher_tobe;
3640 sccipher = sccipher_tobe;
3643 cscomp = cscomp_tobe;
3644 sccomp = sccomp_tobe;
3645 cscomp->compress_init();
3646 sccomp->decompress_init();
3648 * Set IVs after keys. Here we use the exchange hash from the
3649 * _first_ key exchange.
3652 memcpy(ssh2_session_id, exchange_hash, sizeof(exchange_hash));
3653 ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'C', keyspace);
3654 cscipher->setcskey(keyspace);
3655 ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'D', keyspace);
3656 sccipher->setsckey(keyspace);
3657 ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'A', keyspace);
3658 cscipher->setcsiv(keyspace);
3659 ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'B', keyspace);
3660 sccipher->setsciv(keyspace);
3661 ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'E', keyspace);
3662 csmac->setcskey(keyspace);
3663 ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'F', keyspace);
3664 scmac->setsckey(keyspace);
3667 * If this is the first key exchange phase, we must pass the
3668 * SSH2_MSG_NEWKEYS packet to the next layer, not because it
3669 * wants to see it but because it will need time to initialise
3670 * itself before it sees an actual packet. In subsequent key
3671 * exchange phases, we don't pass SSH2_MSG_NEWKEYS on, because
3672 * it would only confuse the layer above.
3680 * Now we're encrypting. Begin returning 1 to the protocol main
3681 * function so that other things can run on top of the
3682 * transport. If we ever see a KEXINIT, we must go back to the
3685 while (!(ispkt && pktin.type == SSH2_MSG_KEXINIT)) {
3688 logevent("Server initiated key re-exchange");
3689 goto begin_key_exchange;
3695 * Add data to an SSH2 channel output buffer.
3697 static void ssh2_add_channel_data(struct ssh_channel *c, char *buf,
3700 bufchain_add(&c->v.v2.outbuffer, buf, len);
3704 * Attempt to send data on an SSH2 channel.
3706 static int ssh2_try_send(struct ssh_channel *c)
3708 while (c->v.v2.remwindow > 0 && bufchain_size(&c->v.v2.outbuffer) > 0) {
3711 bufchain_prefix(&c->v.v2.outbuffer, &data, &len);
3712 if ((unsigned)len > c->v.v2.remwindow)
3713 len = c->v.v2.remwindow;
3714 if ((unsigned)len > c->v.v2.remmaxpkt)
3715 len = c->v.v2.remmaxpkt;
3716 ssh2_pkt_init(SSH2_MSG_CHANNEL_DATA);
3717 ssh2_pkt_adduint32(c->remoteid);
3718 ssh2_pkt_addstring_start();
3719 ssh2_pkt_addstring_data(data, len);
3721 bufchain_consume(&c->v.v2.outbuffer, len);
3722 c->v.v2.remwindow -= len;
3726 * After having sent as much data as we can, return the amount
3729 return bufchain_size(&c->v.v2.outbuffer);
3733 * Potentially enlarge the window on an SSH2 channel.
3735 static void ssh2_set_window(struct ssh_channel *c, unsigned newwin)
3737 if (newwin > c->v.v2.locwindow) {
3738 ssh2_pkt_init(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
3739 ssh2_pkt_adduint32(c->remoteid);
3740 ssh2_pkt_adduint32(newwin - c->v.v2.locwindow);
3742 c->v.v2.locwindow = newwin;
3747 * Handle the SSH2 userauth and connection layers.
3749 static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt)
3752 AUTH_INVALID, AUTH_PUBLICKEY_AGENT, AUTH_PUBLICKEY_FILE,
3754 AUTH_KEYBOARD_INTERACTIVE
3758 AUTH_TYPE_PUBLICKEY,
3759 AUTH_TYPE_PUBLICKEY_OFFER_LOUD,
3760 AUTH_TYPE_PUBLICKEY_OFFER_QUIET,
3762 AUTH_TYPE_KEYBOARD_INTERACTIVE,
3763 AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET
3765 static int gotit, need_pw, can_pubkey, can_passwd, can_keyb_inter;
3766 static int tried_pubkey_config, tried_agent, tried_keyb_inter;
3767 static int kbd_inter_running;
3768 static int we_are_in;
3769 static int num_prompts, echo;
3770 static char username[100];
3771 static char pwprompt[200];
3772 static char password[100];
3773 static void *publickey_blob;
3774 static int publickey_bloblen;
3779 * Request userauth protocol, and await a response to it.
3781 ssh2_pkt_init(SSH2_MSG_SERVICE_REQUEST);
3782 ssh2_pkt_addstring("ssh-userauth");
3784 crWaitUntilV(ispkt);
3785 if (pktin.type != SSH2_MSG_SERVICE_ACCEPT) {
3786 bombout(("Server refused user authentication protocol"));
3791 * We repeat this whole loop, including the username prompt,
3792 * until we manage a successful authentication. If the user
3793 * types the wrong _password_, they are sent back to the
3794 * beginning to try another username. (If they specify a
3795 * username in the config, they are never asked, even if they
3796 * do give a wrong password.)
3798 * I think this best serves the needs of
3800 * - the people who have no configuration, no keys, and just
3801 * want to try repeated (username,password) pairs until they
3802 * type both correctly
3804 * - people who have keys and configuration but occasionally
3805 * need to fall back to passwords
3807 * - people with a key held in Pageant, who might not have
3808 * logged in to a particular machine before; so they want to
3809 * type a username, and then _either_ their key will be
3810 * accepted, _or_ they will type a password. If they mistype
3811 * the username they will want to be able to get back and
3823 if (*username && !cfg.change_username) {
3825 * We got a username last time round this loop, and
3826 * with change_username turned off we don't try to get
3829 } else if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
3831 if (!ssh_get_line("login as: ",
3832 username, sizeof(username), FALSE)) {
3834 * get_line failed to get a username.
3837 logevent("No username provided. Abandoning session.");
3838 ssh_state = SSH_STATE_CLOSED;
3842 c_write_str("login as: ");
3845 crWaitUntilV(!ispkt);
3847 switch (c = *in++) {
3856 c_write_str("\b \b");
3863 c_write_str("\b \b");
3873 if (((c >= ' ' && c <= '~') ||
3874 ((unsigned char) c >= 160))
3875 && pos < sizeof(username)-1) {
3876 username[pos++] = c;
3883 c_write_str("\r\n");
3884 username[strcspn(username, "\n\r")] = '\0';
3887 strncpy(username, cfg.username, 99);
3888 username[99] = '\0';
3889 if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
3890 sprintf(stuff, "Using username \"%s\".\r\n", username);
3896 * Send an authentication request using method "none": (a)
3897 * just in case it succeeds, and (b) so that we know what
3898 * authentication methods we can usefully try next.
3900 ssh_pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
3902 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
3903 ssh2_pkt_addstring(username);
3904 ssh2_pkt_addstring("ssh-connection"); /* service requested */
3905 ssh2_pkt_addstring("none"); /* method */
3907 type = AUTH_TYPE_NONE;
3911 tried_pubkey_config = FALSE;
3912 tried_agent = FALSE;
3913 tried_keyb_inter = FALSE;
3914 kbd_inter_running = FALSE;
3915 /* Load the pub half of cfg.keyfile so we notice if it's in Pageant */
3917 publickey_blob = ssh2_userkey_loadpub(cfg.keyfile, NULL,
3918 &publickey_bloblen);
3920 publickey_blob = NULL;
3924 * Wait for the result of the last authentication request.
3927 crWaitUntilV(ispkt);
3928 while (pktin.type == SSH2_MSG_USERAUTH_BANNER) {
3932 * Don't show the banner if we're operating in
3933 * non-verbose non-interactive mode. (It's probably
3934 * a script, which means nobody will read the
3935 * banner _anyway_, and moreover the printing of
3936 * the banner will screw up processing on the
3937 * output of (say) plink.)
3939 if (flags & (FLAG_VERBOSE | FLAG_INTERACTIVE)) {
3940 ssh2_pkt_getstring(&banner, &size);
3942 c_write_untrusted(banner, size);
3944 crWaitUntilV(ispkt);
3946 if (pktin.type == SSH2_MSG_USERAUTH_SUCCESS) {
3947 logevent("Access granted");
3952 if (kbd_inter_running &&
3953 pktin.type == SSH2_MSG_USERAUTH_INFO_REQUEST) {
3955 * This is a further prompt in keyboard-interactive
3956 * authentication. Do nothing.
3958 } else if (pktin.type != SSH2_MSG_USERAUTH_FAILURE) {
3959 bombout(("Strange packet received during authentication: type %d",
3967 * OK, we're now sitting on a USERAUTH_FAILURE message, so
3968 * we can look at the string in it and know what we can
3969 * helpfully try next.
3971 if (pktin.type == SSH2_MSG_USERAUTH_FAILURE) {
3974 ssh2_pkt_getstring(&methods, &methlen);
3975 kbd_inter_running = FALSE;
3976 if (!ssh2_pkt_getbool()) {
3978 * We have received an unequivocal Access
3979 * Denied. This can translate to a variety of
3982 * - if we'd just tried "none" authentication,
3983 * it's not worth printing anything at all
3985 * - if we'd just tried a public key _offer_,
3986 * the message should be "Server refused our
3987 * key" (or no message at all if the key
3988 * came from Pageant)
3990 * - if we'd just tried anything else, the
3991 * message really should be "Access denied".
3993 * Additionally, if we'd just tried password
3994 * authentication, we should break out of this
3995 * whole loop so as to go back to the username
3998 if (type == AUTH_TYPE_NONE) {
4000 } else if (type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD ||
4001 type == AUTH_TYPE_PUBLICKEY_OFFER_QUIET) {
4002 if (type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD)
4003 c_write_str("Server refused our key\r\n");
4004 logevent("Server refused public key");
4005 } else if (type == AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET) {
4006 /* server declined keyboard-interactive; ignore */
4008 c_write_str("Access denied\r\n");
4009 logevent("Access denied");
4010 if (type == AUTH_TYPE_PASSWORD) {
4016 c_write_str("Further authentication required\r\n");
4017 logevent("Further authentication required");
4021 in_commasep_string("publickey", methods, methlen);
4023 in_commasep_string("password", methods, methlen);
4024 can_keyb_inter = cfg.try_ki_auth &&
4025 in_commasep_string("keyboard-interactive", methods, methlen);
4029 ssh_pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4031 if (!method && can_pubkey && agent_exists() && !tried_agent) {
4033 * Attempt public-key authentication using Pageant.
4035 static unsigned char request[5], *response, *p;
4036 static int responselen;
4037 static int i, nkeys;
4038 static int authed = FALSE;
4041 ssh_pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
4045 logevent("Pageant is running. Requesting keys.");
4047 /* Request the keys held by the agent. */
4048 PUT_32BIT(request, 1);
4049 request[4] = SSH2_AGENTC_REQUEST_IDENTITIES;
4050 agent_query(request, 5, &r, &responselen);
4051 response = (unsigned char *) r;
4052 if (response && responselen >= 5 &&
4053 response[4] == SSH2_AGENT_IDENTITIES_ANSWER) {
4055 nkeys = GET_32BIT(p);
4059 sprintf(buf, "Pageant has %d SSH2 keys", nkeys);
4062 for (i = 0; i < nkeys; i++) {
4063 static char *pkblob, *alg, *commentp;
4064 static int pklen, alglen, commentlen;
4065 static int siglen, retlen, len;
4066 static char *q, *agentreq, *ret;
4071 sprintf(buf, "Trying Pageant key #%d", i);
4074 pklen = GET_32BIT(p);
4076 if (publickey_blob &&
4077 pklen == publickey_bloblen &&
4078 !memcmp(p, publickey_blob, publickey_bloblen)) {
4079 logevent("This key matches configured key file");
4080 tried_pubkey_config = 1;
4084 alglen = GET_32BIT(pkblob);
4086 commentlen = GET_32BIT(p);
4090 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
4091 ssh2_pkt_addstring(username);
4092 ssh2_pkt_addstring("ssh-connection"); /* service requested */
4093 ssh2_pkt_addstring("publickey"); /* method */
4094 ssh2_pkt_addbool(FALSE); /* no signature included */
4095 ssh2_pkt_addstring_start();
4096 ssh2_pkt_addstring_data(alg, alglen);
4097 ssh2_pkt_addstring_start();
4098 ssh2_pkt_addstring_data(pkblob, pklen);
4101 crWaitUntilV(ispkt);
4102 if (pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
4103 logevent("Key refused");
4107 if (flags & FLAG_VERBOSE) {
4109 ("Authenticating with public key \"");
4110 c_write(commentp, commentlen);
4111 c_write_str("\" from agent\r\n");
4115 * Server is willing to accept the key.
4116 * Construct a SIGN_REQUEST.
4118 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
4119 ssh2_pkt_addstring(username);
4120 ssh2_pkt_addstring("ssh-connection"); /* service requested */
4121 ssh2_pkt_addstring("publickey"); /* method */
4122 ssh2_pkt_addbool(TRUE);
4123 ssh2_pkt_addstring_start();
4124 ssh2_pkt_addstring_data(alg, alglen);
4125 ssh2_pkt_addstring_start();
4126 ssh2_pkt_addstring_data(pkblob, pklen);
4128 siglen = pktout.length - 5 + 4 + 20;
4129 len = 1; /* message type */
4130 len += 4 + pklen; /* key blob */
4131 len += 4 + siglen; /* data to sign */
4132 len += 4; /* flags */
4133 agentreq = smalloc(4 + len);
4134 PUT_32BIT(agentreq, len);
4136 *q++ = SSH2_AGENTC_SIGN_REQUEST;
4137 PUT_32BIT(q, pklen);
4139 memcpy(q, pkblob, pklen);
4141 PUT_32BIT(q, siglen);
4143 /* Now the data to be signed... */
4146 memcpy(q, ssh2_session_id, 20);
4148 memcpy(q, pktout.data + 5, pktout.length - 5);
4149 q += pktout.length - 5;
4150 /* And finally the (zero) flags word. */
4152 agent_query(agentreq, len + 4, &vret, &retlen);
4156 if (ret[4] == SSH2_AGENT_SIGN_RESPONSE) {
4157 logevent("Sending Pageant's response");
4158 ssh2_pkt_addstring_start();
4159 ssh2_pkt_addstring_data(ret + 9,
4167 ("Pageant failed to answer challenge");
4177 if (!method && can_pubkey && *cfg.keyfile
4178 && !tried_pubkey_config) {
4179 unsigned char *pub_blob;
4180 char *algorithm, *comment;
4183 tried_pubkey_config = TRUE;
4185 ssh_pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
4188 * Try the public key supplied in the configuration.
4190 * First, offer the public blob to see if the server is
4191 * willing to accept it.
4193 pub_blob = ssh2_userkey_loadpub(cfg.keyfile, &algorithm,
4196 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
4197 ssh2_pkt_addstring(username);
4198 ssh2_pkt_addstring("ssh-connection"); /* service requested */
4199 ssh2_pkt_addstring("publickey"); /* method */
4200 ssh2_pkt_addbool(FALSE); /* no signature included */
4201 ssh2_pkt_addstring(algorithm);
4202 ssh2_pkt_addstring_start();
4203 ssh2_pkt_addstring_data(pub_blob, pub_blob_len);
4205 logevent("Offered public key"); /* FIXME */
4207 crWaitUntilV(ispkt);
4208 if (pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
4210 type = AUTH_TYPE_PUBLICKEY_OFFER_LOUD;
4211 continue; /* key refused; give up on it */
4214 logevent("Offer of public key accepted");
4216 * Actually attempt a serious authentication using
4219 if (ssh2_userkey_encrypted(cfg.keyfile, &comment)) {
4221 "Passphrase for key \"%.100s\": ",
4227 c_write_str("Authenticating with public key \"");
4228 c_write_str(comment);
4229 c_write_str("\"\r\n");
4230 method = AUTH_PUBLICKEY_FILE;
4234 if (!method && can_keyb_inter && !tried_keyb_inter) {
4235 method = AUTH_KEYBOARD_INTERACTIVE;
4236 type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
4237 tried_keyb_inter = TRUE;
4239 ssh_pkt_ctx |= SSH2_PKTCTX_KBDINTER;
4241 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
4242 ssh2_pkt_addstring(username);
4243 ssh2_pkt_addstring("ssh-connection"); /* service requested */
4244 ssh2_pkt_addstring("keyboard-interactive"); /* method */
4245 ssh2_pkt_addstring(""); /* lang */
4246 ssh2_pkt_addstring("");
4249 crWaitUntilV(ispkt);
4250 if (pktin.type != SSH2_MSG_USERAUTH_INFO_REQUEST) {
4251 if (pktin.type == SSH2_MSG_USERAUTH_FAILURE)
4253 logevent("Keyboard-interactive authentication refused");
4254 type = AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET;
4258 kbd_inter_running = TRUE;
4261 if (kbd_inter_running) {
4262 method = AUTH_KEYBOARD_INTERACTIVE;
4263 type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
4264 tried_keyb_inter = TRUE;
4266 ssh_pkt_ctx |= SSH2_PKTCTX_KBDINTER;
4268 /* We've got packet with that "interactive" info
4269 dump banners, and set its prompt as ours */
4271 char *name, *inst, *lang, *prompt;
4272 int name_len, inst_len, lang_len, prompt_len;
4273 ssh2_pkt_getstring(&name, &name_len);
4274 ssh2_pkt_getstring(&inst, &inst_len);
4275 ssh2_pkt_getstring(&lang, &lang_len);
4277 c_write_untrusted(name, name_len);
4279 c_write_untrusted(inst, inst_len);
4280 num_prompts = ssh2_pkt_getuint32();
4282 ssh2_pkt_getstring(&prompt, &prompt_len);
4283 strncpy(pwprompt, prompt, sizeof(pwprompt));
4284 pwprompt[prompt_len < sizeof(pwprompt) ?
4285 prompt_len : sizeof(pwprompt)-1] = '\0';
4288 echo = ssh2_pkt_getbool();
4292 if (!method && can_passwd) {
4293 method = AUTH_PASSWORD;
4294 ssh_pkt_ctx |= SSH2_PKTCTX_PASSWORD;
4295 sprintf(pwprompt, "%.90s@%.90s's password: ", username,
4302 if (!ssh_get_line(pwprompt, password,
4303 sizeof(password), TRUE)) {
4305 * get_line failed to get a password (for
4306 * example because one was supplied on the
4307 * command line which has already failed to
4310 ssh2_pkt_init(SSH2_MSG_DISCONNECT);
4311 ssh2_pkt_adduint32(SSH2_DISCONNECT_BY_APPLICATION);
4313 ("No more passwords available to try");
4314 ssh2_pkt_addstring("en"); /* language tag */
4316 connection_fatal("Unable to authenticate");
4317 ssh_state = SSH_STATE_CLOSED;
4324 c_write_untrusted(pwprompt, strlen(pwprompt));
4329 crWaitUntilV(!ispkt);
4331 switch (c = *in++) {
4352 if (pos < sizeof(password)-1)
4353 password[pos++] = c;
4357 c_write_str("\r\n");
4361 if (method == AUTH_PUBLICKEY_FILE) {
4363 * We have our passphrase. Now try the actual authentication.
4365 struct ssh2_userkey *key;
4367 key = ssh2_load_userkey(cfg.keyfile, password);
4368 if (key == SSH2_WRONG_PASSPHRASE || key == NULL) {
4369 if (key == SSH2_WRONG_PASSPHRASE) {
4370 c_write_str("Wrong passphrase\r\n");
4371 tried_pubkey_config = FALSE;
4373 c_write_str("Unable to load private key\r\n");
4374 tried_pubkey_config = TRUE;
4376 /* Send a spurious AUTH_NONE to return to the top. */
4377 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
4378 ssh2_pkt_addstring(username);
4379 ssh2_pkt_addstring("ssh-connection"); /* service requested */
4380 ssh2_pkt_addstring("none"); /* method */
4382 type = AUTH_TYPE_NONE;
4384 unsigned char *blob, *sigdata;
4385 int blob_len, sigdata_len;
4388 * We have loaded the private key and the server
4389 * has announced that it's willing to accept it.
4390 * Hallelujah. Generate a signature and send it.
4392 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
4393 ssh2_pkt_addstring(username);
4394 ssh2_pkt_addstring("ssh-connection"); /* service requested */
4395 ssh2_pkt_addstring("publickey"); /* method */
4396 ssh2_pkt_addbool(TRUE);
4397 ssh2_pkt_addstring(key->alg->name);
4398 blob = key->alg->public_blob(key->data, &blob_len);
4399 ssh2_pkt_addstring_start();
4400 ssh2_pkt_addstring_data(blob, blob_len);
4404 * The data to be signed is:
4408 * followed by everything so far placed in the
4411 sigdata_len = pktout.length - 5 + 4 + 20;
4412 sigdata = smalloc(sigdata_len);
4413 PUT_32BIT(sigdata, 20);
4414 memcpy(sigdata + 4, ssh2_session_id, 20);
4415 memcpy(sigdata + 24, pktout.data + 5,
4418 key->alg->sign(key->data, sigdata, sigdata_len,
4420 ssh2_pkt_addstring_start();
4421 ssh2_pkt_addstring_data(blob, blob_len);
4426 type = AUTH_TYPE_PUBLICKEY;
4428 } else if (method == AUTH_PASSWORD) {
4430 * We send the password packet lumped tightly together with
4431 * an SSH_MSG_IGNORE packet. The IGNORE packet contains a
4432 * string long enough to make the total length of the two
4433 * packets constant. This should ensure that a passive
4434 * listener doing traffic analyis can't work out the length
4437 * For this to work, we need an assumption about the
4438 * maximum length of the password packet. I think 256 is
4439 * pretty conservative. Anyone using a password longer than
4440 * that probably doesn't have much to worry about from
4441 * people who find out how long their password is!
4443 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
4444 ssh2_pkt_addstring(username);
4445 ssh2_pkt_addstring("ssh-connection"); /* service requested */
4446 ssh2_pkt_addstring("password");
4447 ssh2_pkt_addbool(FALSE);
4448 ssh2_pkt_addstring(password);
4451 * We'll include a string that's an exact multiple of the
4452 * cipher block size. If the cipher is NULL for some
4453 * reason, we don't do this trick at all because we gain
4459 stringlen = (256 - deferred_len);
4460 stringlen += cscipher->blksize - 1;
4461 stringlen -= (stringlen % cscipher->blksize);
4464 * Temporarily disable actual compression,
4465 * so we can guarantee to get this string
4466 * exactly the length we want it. The
4467 * compression-disabling routine should
4468 * return an integer indicating how many
4469 * bytes we should adjust our string length
4472 stringlen -= cscomp->disable_compression();
4474 ssh2_pkt_init(SSH2_MSG_IGNORE);
4475 ssh2_pkt_addstring_start();
4476 for (i = 0; i < stringlen; i++) {
4477 char c = (char) random_byte();
4478 ssh2_pkt_addstring_data(&c, 1);
4482 ssh_pkt_defersend();
4483 logevent("Sent password");
4484 type = AUTH_TYPE_PASSWORD;
4485 } else if (method == AUTH_KEYBOARD_INTERACTIVE) {
4486 ssh2_pkt_init(SSH2_MSG_USERAUTH_INFO_RESPONSE);
4487 ssh2_pkt_adduint32(num_prompts);
4488 ssh2_pkt_addstring(password);
4489 memset(password, 0, sizeof(password));
4491 type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
4494 ("No supported authentication methods left to try!\r\n");
4496 ("No supported authentications offered. Disconnecting");
4497 ssh2_pkt_init(SSH2_MSG_DISCONNECT);
4498 ssh2_pkt_adduint32(SSH2_DISCONNECT_BY_APPLICATION);
4500 ("No supported authentication methods available");
4501 ssh2_pkt_addstring("en"); /* language tag */
4503 ssh_state = SSH_STATE_CLOSED;
4507 } while (!we_are_in);
4510 * Now we're authenticated for the connection protocol. The
4511 * connection protocol will automatically have started at this
4512 * point; there's no need to send SERVICE_REQUEST.
4516 * So now create a channel with a session in it.
4518 ssh_channels = newtree234(ssh_channelcmp);
4519 mainchan = smalloc(sizeof(struct ssh_channel));
4520 mainchan->localid = alloc_channel_id();
4521 ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN);
4522 ssh2_pkt_addstring("session");
4523 ssh2_pkt_adduint32(mainchan->localid);
4524 mainchan->v.v2.locwindow = OUR_V2_WINSIZE;
4525 ssh2_pkt_adduint32(mainchan->v.v2.locwindow); /* our window size */
4526 ssh2_pkt_adduint32(0x4000UL); /* our max pkt size */
4528 crWaitUntilV(ispkt);
4529 if (pktin.type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
4530 bombout(("Server refused to open a session"));
4532 /* FIXME: error data comes back in FAILURE packet */
4534 if (ssh2_pkt_getuint32() != mainchan->localid) {
4535 bombout(("Server's channel confirmation cited wrong channel"));
4538 mainchan->remoteid = ssh2_pkt_getuint32();
4539 mainchan->type = CHAN_MAINSESSION;
4540 mainchan->closes = 0;
4541 mainchan->v.v2.remwindow = ssh2_pkt_getuint32();
4542 mainchan->v.v2.remmaxpkt = ssh2_pkt_getuint32();
4543 bufchain_init(&mainchan->v.v2.outbuffer);
4544 add234(ssh_channels, mainchan);
4545 logevent("Opened channel for session");
4548 * Potentially enable X11 forwarding.
4550 if (cfg.x11_forward) {
4551 char proto[20], data[64];
4552 logevent("Requesting X11 forwarding");
4553 x11_invent_auth(proto, sizeof(proto), data, sizeof(data));
4554 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
4555 ssh2_pkt_adduint32(mainchan->remoteid);
4556 ssh2_pkt_addstring("x11-req");
4557 ssh2_pkt_addbool(1); /* want reply */
4558 ssh2_pkt_addbool(0); /* many connections */
4559 ssh2_pkt_addstring(proto);
4560 ssh2_pkt_addstring(data);
4561 ssh2_pkt_adduint32(0); /* screen number */
4565 crWaitUntilV(ispkt);
4566 if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
4567 unsigned i = ssh2_pkt_getuint32();
4568 struct ssh_channel *c;
4569 c = find234(ssh_channels, &i, ssh_channelfind);
4571 continue; /* nonexistent channel */
4572 c->v.v2.remwindow += ssh2_pkt_getuint32();
4574 } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
4576 if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
4577 if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
4578 bombout(("Unexpected response to X11 forwarding request:"
4579 " packet type %d", pktin.type));
4582 logevent("X11 forwarding refused");
4584 logevent("X11 forwarding enabled");
4585 ssh_X11_fwd_enabled = TRUE;
4590 * Enable port forwardings.
4593 static char *e; /* preserve across crReturn */
4597 char sports[256], dports[256], host[256];
4600 ssh_rportfwds = newtree234(ssh_rportcmp_ssh2);
4601 /* Add port forwardings. */
4606 while (*e && *e != '\t')
4612 while (*e && *e != ':')
4622 dport = atoi(dports);
4623 sport = atoi(sports);
4624 if (sport && dport) {
4626 pfd_addforward(host, dport, sport);
4627 sprintf(buf, "Local port %d forwarding to %s:%d",
4628 sport, host, dport);
4631 struct ssh_rportfwd *pf;
4632 pf = smalloc(sizeof(*pf));
4633 strcpy(pf->dhost, host);
4636 if (add234(ssh_rportfwds, pf) != pf) {
4638 "Duplicate remote port forwarding to %s:%d",
4643 sprintf(buf, "Requesting remote port %d (forwarded to %s:%d)",
4644 sport, host, dport);
4646 ssh2_pkt_init(SSH2_MSG_GLOBAL_REQUEST);
4647 ssh2_pkt_addstring("tcpip-forward");
4648 ssh2_pkt_addbool(1);/* want reply */
4649 if (cfg.rport_acceptall)
4650 ssh2_pkt_addstring("0.0.0.0");
4652 ssh2_pkt_addstring("127.0.0.1");
4653 ssh2_pkt_adduint32(sport);
4657 crWaitUntilV(ispkt);
4658 if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
4659 unsigned i = ssh2_pkt_getuint32();
4660 struct ssh_channel *c;
4661 c = find234(ssh_channels, &i, ssh_channelfind);
4663 continue;/* nonexistent channel */
4664 c->v.v2.remwindow += ssh2_pkt_getuint32();
4666 } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
4668 if (pktin.type != SSH2_MSG_REQUEST_SUCCESS) {
4669 if (pktin.type != SSH2_MSG_REQUEST_FAILURE) {
4670 bombout(("Unexpected response to port "
4671 "forwarding request: packet type %d",
4675 logevent("Server refused this port forwarding");
4677 logevent("Remote port forwarding enabled");
4686 * Potentially enable agent forwarding.
4688 if (cfg.agentfwd && agent_exists()) {
4689 logevent("Requesting OpenSSH-style agent forwarding");
4690 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
4691 ssh2_pkt_adduint32(mainchan->remoteid);
4692 ssh2_pkt_addstring("auth-agent-req@openssh.com");
4693 ssh2_pkt_addbool(1); /* want reply */
4697 crWaitUntilV(ispkt);
4698 if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
4699 unsigned i = ssh2_pkt_getuint32();
4700 struct ssh_channel *c;
4701 c = find234(ssh_channels, &i, ssh_channelfind);
4703 continue; /* nonexistent channel */
4704 c->v.v2.remwindow += ssh2_pkt_getuint32();
4706 } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
4708 if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
4709 if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
4710 bombout(("Unexpected response to agent forwarding request:"
4711 " packet type %d", pktin.type));
4714 logevent("Agent forwarding refused");
4716 logevent("Agent forwarding enabled");
4717 ssh_agentfwd_enabled = TRUE;
4722 * Now allocate a pty for the session.
4725 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
4726 ssh2_pkt_adduint32(mainchan->remoteid); /* recipient channel */
4727 ssh2_pkt_addstring("pty-req");
4728 ssh2_pkt_addbool(1); /* want reply */
4729 ssh2_pkt_addstring(cfg.termtype);
4730 ssh2_pkt_adduint32(cols);
4731 ssh2_pkt_adduint32(rows);
4732 ssh2_pkt_adduint32(0); /* pixel width */
4733 ssh2_pkt_adduint32(0); /* pixel height */
4734 ssh2_pkt_addstring_start();
4735 ssh2_pkt_addstring_data("\0", 1); /* TTY_OP_END, no special options */
4737 ssh_state = SSH_STATE_INTERMED;
4740 crWaitUntilV(ispkt);
4741 if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
4742 unsigned i = ssh2_pkt_getuint32();
4743 struct ssh_channel *c;
4744 c = find234(ssh_channels, &i, ssh_channelfind);
4746 continue; /* nonexistent channel */
4747 c->v.v2.remwindow += ssh2_pkt_getuint32();
4749 } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
4751 if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
4752 if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
4753 bombout(("Unexpected response to pty request:"
4754 " packet type %d", pktin.type));
4757 c_write_str("Server refused to allocate pty\r\n");
4758 ssh_editing = ssh_echoing = 1;
4760 logevent("Allocated pty");
4763 ssh_editing = ssh_echoing = 1;
4767 * Start a shell or a remote command. We may have to attempt
4768 * this twice if the config data has provided a second choice
4775 if (ssh_fallback_cmd) {
4776 subsys = cfg.ssh_subsys2;
4777 cmd = cfg.remote_cmd_ptr2;
4779 subsys = cfg.ssh_subsys;
4780 cmd = cfg.remote_cmd_ptr;
4783 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
4784 ssh2_pkt_adduint32(mainchan->remoteid); /* recipient channel */
4786 ssh2_pkt_addstring("subsystem");
4787 ssh2_pkt_addbool(1); /* want reply */
4788 ssh2_pkt_addstring(cmd);
4790 ssh2_pkt_addstring("exec");
4791 ssh2_pkt_addbool(1); /* want reply */
4792 ssh2_pkt_addstring(cmd);
4794 ssh2_pkt_addstring("shell");
4795 ssh2_pkt_addbool(1); /* want reply */
4799 crWaitUntilV(ispkt);
4800 if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
4801 unsigned i = ssh2_pkt_getuint32();
4802 struct ssh_channel *c;
4803 c = find234(ssh_channels, &i, ssh_channelfind);
4805 continue; /* nonexistent channel */
4806 c->v.v2.remwindow += ssh2_pkt_getuint32();
4808 } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
4809 if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
4810 if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
4811 bombout(("Unexpected response to shell/command request:"
4812 " packet type %d", pktin.type));
4816 * We failed to start the command. If this is the
4817 * fallback command, we really are finished; if it's
4818 * not, and if the fallback command exists, try falling
4819 * back to it before complaining.
4821 if (!ssh_fallback_cmd && cfg.remote_cmd_ptr2 != NULL) {
4822 logevent("Primary command failed; attempting fallback");
4823 ssh_fallback_cmd = TRUE;
4826 bombout(("Server refused to start a shell/command"));
4829 logevent("Started a shell/command");
4834 ssh_state = SSH_STATE_SESSION;
4838 ssh_special(TS_EOF);
4843 ldisc_send(NULL, 0, 0); /* cause ldisc to notice changes */
4846 static int try_send;
4850 if (pktin.type == SSH2_MSG_CHANNEL_DATA ||
4851 pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA) {
4854 unsigned i = ssh2_pkt_getuint32();
4855 struct ssh_channel *c;
4856 c = find234(ssh_channels, &i, ssh_channelfind);
4858 continue; /* nonexistent channel */
4859 if (pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
4860 ssh2_pkt_getuint32() != SSH2_EXTENDED_DATA_STDERR)
4861 continue; /* extended but not stderr */
4862 ssh2_pkt_getstring(&data, &length);
4865 c->v.v2.locwindow -= length;
4867 case CHAN_MAINSESSION:
4869 from_backend(pktin.type ==
4870 SSH2_MSG_CHANNEL_EXTENDED_DATA,
4874 bufsize = x11_send(c->u.x11.s, data, length);
4877 bufsize = pfd_send(c->u.pfd.s, data, length);
4880 while (length > 0) {
4881 if (c->u.a.lensofar < 4) {
4882 int l = min(4 - c->u.a.lensofar, length);
4883 memcpy(c->u.a.msglen + c->u.a.lensofar,
4887 c->u.a.lensofar += l;
4889 if (c->u.a.lensofar == 4) {
4891 4 + GET_32BIT(c->u.a.msglen);
4892 c->u.a.message = smalloc(c->u.a.totallen);
4893 memcpy(c->u.a.message, c->u.a.msglen, 4);
4895 if (c->u.a.lensofar >= 4 && length > 0) {
4897 min(c->u.a.totallen - c->u.a.lensofar,
4899 memcpy(c->u.a.message + c->u.a.lensofar,
4903 c->u.a.lensofar += l;
4905 if (c->u.a.lensofar == c->u.a.totallen) {
4906 void *reply, *sentreply;
4908 agent_query(c->u.a.message,
4909 c->u.a.totallen, &reply,
4914 /* Fake SSH_AGENT_FAILURE. */
4915 sentreply = "\0\0\0\1\5";
4918 ssh2_add_channel_data(c, sentreply,
4923 sfree(c->u.a.message);
4924 c->u.a.lensofar = 0;
4931 * If we are not buffering too much data,
4932 * enlarge the window again at the remote side.
4934 if (bufsize < OUR_V2_WINSIZE)
4935 ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
4937 } else if (pktin.type == SSH2_MSG_DISCONNECT) {
4938 ssh_state = SSH_STATE_CLOSED;
4939 logevent("Received disconnect message");
4941 } else if (pktin.type == SSH2_MSG_CHANNEL_EOF) {
4942 unsigned i = ssh2_pkt_getuint32();
4943 struct ssh_channel *c;
4945 c = find234(ssh_channels, &i, ssh_channelfind);
4947 continue; /* nonexistent channel */
4949 if (c->type == CHAN_X11) {
4951 * Remote EOF on an X11 channel means we should
4952 * wrap up and close the channel ourselves.
4954 x11_close(c->u.x11.s);
4956 } else if (c->type == CHAN_AGENT) {
4958 } else if (c->type == CHAN_SOCKDATA) {
4959 pfd_close(c->u.pfd.s);
4962 } else if (pktin.type == SSH2_MSG_CHANNEL_CLOSE) {
4963 unsigned i = ssh2_pkt_getuint32();
4964 struct ssh_channel *c;
4966 c = find234(ssh_channels, &i, ssh_channelfind);
4968 continue; /* nonexistent channel */
4969 /* Do pre-close processing on the channel. */
4971 case CHAN_MAINSESSION:
4972 break; /* nothing to see here, move along */
4974 if (c->u.x11.s != NULL)
4975 x11_close(c->u.x11.s);
4982 if (c->u.pfd.s != NULL)
4983 pfd_close(c->u.pfd.s);
4987 if (c->closes == 0) {
4988 ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE);
4989 ssh2_pkt_adduint32(c->remoteid);
4992 del234(ssh_channels, c);
4993 bufchain_clear(&c->v.v2.outbuffer);
4997 * See if that was the last channel left open.
4999 if (count234(ssh_channels) == 0) {
5002 * We used to send SSH_MSG_DISCONNECT here,
5003 * because I'd believed that _every_ conforming
5004 * SSH2 connection had to end with a disconnect
5005 * being sent by at least one side; apparently
5006 * I was wrong and it's perfectly OK to
5007 * unceremoniously slam the connection shut
5008 * when you're done, and indeed OpenSSH feels
5009 * this is more polite than sending a
5010 * DISCONNECT. So now we don't.
5012 logevent("All channels closed. Disconnecting");
5013 ssh2_pkt_init(SSH2_MSG_DISCONNECT);
5014 ssh2_pkt_adduint32(SSH2_DISCONNECT_BY_APPLICATION);
5015 ssh2_pkt_addstring("All open channels closed");
5016 ssh2_pkt_addstring("en"); /* language tag */
5019 ssh_state = SSH_STATE_CLOSED;
5022 continue; /* remote sends close; ignore (FIXME) */
5023 } else if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5024 unsigned i = ssh2_pkt_getuint32();
5025 struct ssh_channel *c;
5026 c = find234(ssh_channels, &i, ssh_channelfind);
5028 continue; /* nonexistent channel */
5029 c->v.v2.remwindow += ssh2_pkt_getuint32();
5031 } else if (pktin.type == SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
5032 unsigned i = ssh2_pkt_getuint32();
5033 struct ssh_channel *c;
5034 c = find234(ssh_channels, &i, ssh_channelfind);
5036 continue; /* nonexistent channel */
5037 if (c->type != CHAN_SOCKDATA_DORMANT)
5038 continue; /* dunno why they're confirming this */
5039 c->remoteid = ssh2_pkt_getuint32();
5040 c->type = CHAN_SOCKDATA;
5041 c->v.v2.remwindow = ssh2_pkt_getuint32();
5042 c->v.v2.remmaxpkt = ssh2_pkt_getuint32();
5043 bufchain_init(&c->v.v2.outbuffer);
5045 pfd_confirm(c->u.pfd.s);
5048 * We have a pending close on this channel,
5049 * which we decided on before the server acked
5050 * the channel open. So now we know the
5051 * remoteid, we can close it again.
5053 ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE);
5054 ssh2_pkt_adduint32(c->remoteid);
5057 } else if (pktin.type == SSH2_MSG_CHANNEL_OPEN_FAILURE) {
5058 unsigned i = ssh2_pkt_getuint32();
5059 struct ssh_channel *c;
5060 c = find234(ssh_channels, &i, ssh_channelfind);
5062 continue; /* nonexistent channel */
5063 if (c->type != CHAN_SOCKDATA_DORMANT)
5064 continue; /* dunno why they're failing this */
5066 logevent("Forwarded connection refused by server");
5068 pfd_close(c->u.pfd.s);
5070 del234(ssh_channels, c);
5072 } else if (pktin.type == SSH2_MSG_CHANNEL_REQUEST) {
5075 int typelen, want_reply;
5076 struct ssh_channel *c;
5078 localid = ssh2_pkt_getuint32();
5079 ssh2_pkt_getstring(&type, &typelen);
5080 want_reply = ssh2_pkt_getbool();
5083 * First, check that the channel exists. Otherwise,
5084 * we can instantly disconnect with a rude message.
5086 c = find234(ssh_channels, &localid, ssh_channelfind);
5089 sprintf(buf, "Received channel request for nonexistent"
5090 " channel %d", localid);
5092 ssh2_pkt_init(SSH2_MSG_DISCONNECT);
5093 ssh2_pkt_adduint32(SSH2_DISCONNECT_BY_APPLICATION);
5094 ssh2_pkt_addstring(buf);
5095 ssh2_pkt_addstring("en"); /* language tag */
5097 connection_fatal(buf);
5098 ssh_state = SSH_STATE_CLOSED;
5103 * Having got the channel number, we now look at
5104 * the request type string to see if it's something
5107 if (typelen == 11 && !memcmp(type, "exit-status", 11) &&
5109 /* We recognise "exit-status" on the primary channel. */
5111 ssh_exitcode = ssh2_pkt_getuint32();
5112 sprintf(buf, "Server sent command exit status %d",
5116 ssh2_pkt_init(SSH2_MSG_CHANNEL_SUCCESS);
5117 ssh2_pkt_adduint32(c->remoteid);
5122 * This is a channel request we don't know
5123 * about, so we now either ignore the request
5124 * or respond with CHANNEL_FAILURE, depending
5128 ssh2_pkt_init(SSH2_MSG_CHANNEL_FAILURE);
5129 ssh2_pkt_adduint32(c->remoteid);
5133 } else if (pktin.type == SSH2_MSG_CHANNEL_OPEN) {
5137 struct ssh_channel *c;
5138 unsigned remid, winsize, pktsize;
5139 ssh2_pkt_getstring(&type, &typelen);
5140 c = smalloc(sizeof(struct ssh_channel));
5142 remid = ssh2_pkt_getuint32();
5143 winsize = ssh2_pkt_getuint32();
5144 pktsize = ssh2_pkt_getuint32();
5146 if (typelen == 3 && !memcmp(type, "x11", 3)) {
5147 if (!ssh_X11_fwd_enabled)
5148 error = "X11 forwarding is not enabled";
5149 else if (x11_init(&c->u.x11.s, cfg.x11_display, c) !=
5151 error = "Unable to open an X11 connection";
5155 } else if (typelen == 15 &&
5156 !memcmp(type, "forwarded-tcpip", 15)) {
5157 struct ssh_rportfwd pf, *realpf;
5160 ssh2_pkt_getstring(&dummy, &dummylen);/* skip address */
5161 pf.sport = ssh2_pkt_getuint32();
5162 realpf = find234(ssh_rportfwds, &pf, NULL);
5163 if (realpf == NULL) {
5164 error = "Remote port is not recognised";
5166 char *e = pfd_newconnect(&c->u.pfd.s, realpf->dhost,
5169 sprintf(buf, "Received remote port open request for %s:%d",
5170 realpf->dhost, realpf->dport);
5173 sprintf(buf, "Port open failed: %s", e);
5175 error = "Port open failed";
5177 logevent("Forwarded port opened successfully");
5178 c->type = CHAN_SOCKDATA;
5181 } else if (typelen == 22 &&
5182 !memcmp(type, "auth-agent@openssh.com", 3)) {
5183 if (!ssh_agentfwd_enabled)
5184 error = "Agent forwarding is not enabled";
5186 c->type = CHAN_AGENT; /* identify channel type */
5187 c->u.a.lensofar = 0;
5190 error = "Unsupported channel type requested";
5193 c->remoteid = remid;
5195 ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_FAILURE);
5196 ssh2_pkt_adduint32(c->remoteid);
5197 ssh2_pkt_adduint32(SSH2_OPEN_CONNECT_FAILED);
5198 ssh2_pkt_addstring(error);
5199 ssh2_pkt_addstring("en"); /* language tag */
5203 c->localid = alloc_channel_id();
5205 c->v.v2.locwindow = OUR_V2_WINSIZE;
5206 c->v.v2.remwindow = winsize;
5207 c->v.v2.remmaxpkt = pktsize;
5208 bufchain_init(&c->v.v2.outbuffer);
5209 add234(ssh_channels, c);
5210 ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
5211 ssh2_pkt_adduint32(c->remoteid);
5212 ssh2_pkt_adduint32(c->localid);
5213 ssh2_pkt_adduint32(c->v.v2.locwindow);
5214 ssh2_pkt_adduint32(0x4000UL); /* our max pkt size */
5218 bombout(("Strange packet received: type %d", pktin.type));
5223 * We have spare data. Add it to the channel buffer.
5225 ssh2_add_channel_data(mainchan, in, inlen);
5230 struct ssh_channel *c;
5232 * Try to send data on all channels if we can.
5234 for (i = 0; NULL != (c = index234(ssh_channels, i)); i++) {
5235 int bufsize = ssh2_try_send(c);
5238 case CHAN_MAINSESSION:
5239 /* stdin need not receive an unthrottle
5240 * notification since it will be polled */
5243 x11_unthrottle(c->u.x11.s);
5246 /* agent sockets are request/response and need no
5247 * buffer management */
5250 pfd_unthrottle(c->u.pfd.s);
5262 * Handle the top-level SSH2 protocol.
5264 static void ssh2_protocol(unsigned char *in, int inlen, int ispkt)
5266 if (do_ssh2_transport(in, inlen, ispkt) == 0)
5268 do_ssh2_authconn(in, inlen, ispkt);
5272 * Called to set up the connection.
5274 * Returns an error message, or NULL on success.
5276 static char *ssh_init(char *host, int port, char **realhost, int nodelay)
5281 if (crypto_startup() == 0)
5282 return "Microsoft high encryption pack not installed!";
5288 ssh1_throttle_count = 0;
5289 ssh_overall_bufsize = 0;
5290 ssh_fallback_cmd = 0;
5292 p = connect_to_host(host, port, realhost, nodelay);
5300 * Called to send data down the Telnet connection.
5302 static int ssh_send(char *buf, int len)
5304 if (s == NULL || ssh_protocol == NULL)
5307 ssh_protocol(buf, len, 0);
5309 return ssh_sendbuffer();
5313 * Called to query the current amount of buffered stdin data.
5315 static int ssh_sendbuffer(void)
5319 if (s == NULL || ssh_protocol == NULL)
5323 * If the SSH socket itself has backed up, add the total backup
5324 * size on that to any individual buffer on the stdin channel.
5327 if (ssh_throttled_all)
5328 override_value = ssh_overall_bufsize;
5330 if (ssh_version == 1) {
5331 return override_value;
5332 } else if (ssh_version == 2) {
5333 if (!mainchan || mainchan->closes > 0)
5334 return override_value;
5336 return override_value + bufchain_size(&mainchan->v.v2.outbuffer);
5343 * Called to set the size of the window from SSH's POV.
5345 static void ssh_size(void)
5347 switch (ssh_state) {
5348 case SSH_STATE_BEFORE_SIZE:
5349 case SSH_STATE_PREPACKET:
5350 case SSH_STATE_CLOSED:
5351 break; /* do nothing */
5352 case SSH_STATE_INTERMED:
5353 size_needed = TRUE; /* buffer for later */
5355 case SSH_STATE_SESSION:
5357 if (ssh_version == 1) {
5358 send_packet(SSH1_CMSG_WINDOW_SIZE,
5359 PKT_INT, rows, PKT_INT, cols,
5360 PKT_INT, 0, PKT_INT, 0, PKT_END);
5362 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
5363 ssh2_pkt_adduint32(mainchan->remoteid);
5364 ssh2_pkt_addstring("window-change");
5365 ssh2_pkt_addbool(0);
5366 ssh2_pkt_adduint32(cols);
5367 ssh2_pkt_adduint32(rows);
5368 ssh2_pkt_adduint32(0);
5369 ssh2_pkt_adduint32(0);
5378 * Send Telnet special codes. TS_EOF is useful for `plink', so you
5379 * can send an EOF and collect resulting output (e.g. `plink
5382 static void ssh_special(Telnet_Special code)
5384 if (code == TS_EOF) {
5385 if (ssh_state != SSH_STATE_SESSION) {
5387 * Buffer the EOF in case we are pre-SESSION, so we can
5388 * send it as soon as we reach SESSION.
5394 if (ssh_version == 1) {
5395 send_packet(SSH1_CMSG_EOF, PKT_END);
5397 ssh2_pkt_init(SSH2_MSG_CHANNEL_EOF);
5398 ssh2_pkt_adduint32(mainchan->remoteid);
5401 logevent("Sent EOF message");
5402 } else if (code == TS_PING) {
5403 if (ssh_state == SSH_STATE_CLOSED
5404 || ssh_state == SSH_STATE_PREPACKET) return;
5405 if (ssh_version == 1) {
5406 send_packet(SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
5408 ssh2_pkt_init(SSH2_MSG_IGNORE);
5409 ssh2_pkt_addstring_start();
5417 void *new_sock_channel(Socket s)
5419 struct ssh_channel *c;
5420 c = smalloc(sizeof(struct ssh_channel));
5423 c->remoteid = -1; /* to be set when open confirmed */
5424 c->localid = alloc_channel_id();
5426 c->type = CHAN_SOCKDATA_DORMANT;/* identify channel type */
5428 add234(ssh_channels, c);
5434 * This is called when stdout/stderr (the entity to which
5435 * from_backend sends data) manages to clear some backlog.
5437 void ssh_unthrottle(int bufsize)
5439 if (ssh_version == 1) {
5440 if (ssh1_stdout_throttling && bufsize < SSH1_BUFFER_LIMIT) {
5441 ssh1_stdout_throttling = 0;
5445 if (mainchan && mainchan->closes == 0)
5446 ssh2_set_window(mainchan, OUR_V2_WINSIZE - bufsize);
5450 void ssh_send_port_open(void *channel, char *hostname, int port, char *org)
5452 struct ssh_channel *c = (struct ssh_channel *)channel;
5455 sprintf(buf, "Opening forwarded connection to %.512s:%d", hostname, port);
5458 if (ssh_version == 1) {
5459 send_packet(SSH1_MSG_PORT_OPEN,
5460 PKT_INT, c->localid,
5463 //PKT_STR, <org:orgport>,
5466 ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN);
5467 ssh2_pkt_addstring("direct-tcpip");
5468 ssh2_pkt_adduint32(c->localid);
5469 c->v.v2.locwindow = OUR_V2_WINSIZE;
5470 ssh2_pkt_adduint32(c->v.v2.locwindow);/* our window size */
5471 ssh2_pkt_adduint32(0x4000UL); /* our max pkt size */
5472 ssh2_pkt_addstring(hostname);
5473 ssh2_pkt_adduint32(port);
5475 * We make up values for the originator data; partly it's
5476 * too much hassle to keep track, and partly I'm not
5477 * convinced the server should be told details like that
5478 * about my local network configuration.
5480 ssh2_pkt_addstring("client-side-connection");
5481 ssh2_pkt_adduint32(0);
5487 static Socket ssh_socket(void)
5492 static int ssh_sendok(void)
5497 static int ssh_ldisc(int option)
5499 if (option == LD_ECHO)
5501 if (option == LD_EDIT)
5506 static int ssh_return_exitcode(void)
5508 return ssh_exitcode;
5511 Backend ssh_backend = {
5518 ssh_return_exitcode,