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Experimental checkin to see if we can prevent multiple closes ever
[sgt/putty] / ssh.c
1 #include <windows.h>
2 #include <stdio.h>
3 #include <stdlib.h>
4 #include <stdarg.h>
5 #include <assert.h>
6
7 #include "putty.h"
8 #include "tree234.h"
9 #include "ssh.h"
10
11 #ifndef FALSE
12 #define FALSE 0
13 #endif
14 #ifndef TRUE
15 #define TRUE 1
16 #endif
17
18 #define logevent(s) { logevent(s); \
19 if ((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)) \
20 fprintf(stderr, "%s\n", s); }
21
22 #define bombout(msg) ( ssh_state = SSH_STATE_CLOSED, \
23 (s ? sk_close(s), s = NULL : 0), \
24 connection_fatal msg )
25
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 */
67
68 #define SSH1_AUTH_TIS 5 /* 0x5 */
69 #define SSH1_AUTH_CCARD 16 /* 0x10 */
70
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 */
74
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_GLOBAL_REQUEST 80 /* 0x50 */
96 #define SSH2_MSG_REQUEST_SUCCESS 81 /* 0x51 */
97 #define SSH2_MSG_REQUEST_FAILURE 82 /* 0x52 */
98 #define SSH2_MSG_CHANNEL_OPEN 90 /* 0x5a */
99 #define SSH2_MSG_CHANNEL_OPEN_CONFIRMATION 91 /* 0x5b */
100 #define SSH2_MSG_CHANNEL_OPEN_FAILURE 92 /* 0x5c */
101 #define SSH2_MSG_CHANNEL_WINDOW_ADJUST 93 /* 0x5d */
102 #define SSH2_MSG_CHANNEL_DATA 94 /* 0x5e */
103 #define SSH2_MSG_CHANNEL_EXTENDED_DATA 95 /* 0x5f */
104 #define SSH2_MSG_CHANNEL_EOF 96 /* 0x60 */
105 #define SSH2_MSG_CHANNEL_CLOSE 97 /* 0x61 */
106 #define SSH2_MSG_CHANNEL_REQUEST 98 /* 0x62 */
107 #define SSH2_MSG_CHANNEL_SUCCESS 99 /* 0x63 */
108 #define SSH2_MSG_CHANNEL_FAILURE 100 /* 0x64 */
109
110 #define SSH2_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT 1 /* 0x1 */
111 #define SSH2_DISCONNECT_PROTOCOL_ERROR 2 /* 0x2 */
112 #define SSH2_DISCONNECT_KEY_EXCHANGE_FAILED 3 /* 0x3 */
113 #define SSH2_DISCONNECT_HOST_AUTHENTICATION_FAILED 4 /* 0x4 */
114 #define SSH2_DISCONNECT_MAC_ERROR 5 /* 0x5 */
115 #define SSH2_DISCONNECT_COMPRESSION_ERROR 6 /* 0x6 */
116 #define SSH2_DISCONNECT_SERVICE_NOT_AVAILABLE 7 /* 0x7 */
117 #define SSH2_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED 8 /* 0x8 */
118 #define SSH2_DISCONNECT_HOST_KEY_NOT_VERIFIABLE 9 /* 0x9 */
119 #define SSH2_DISCONNECT_CONNECTION_LOST 10 /* 0xa */
120 #define SSH2_DISCONNECT_BY_APPLICATION 11 /* 0xb */
121
122 #define SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED 1 /* 0x1 */
123 #define SSH2_OPEN_CONNECT_FAILED 2 /* 0x2 */
124 #define SSH2_OPEN_UNKNOWN_CHANNEL_TYPE 3 /* 0x3 */
125 #define SSH2_OPEN_RESOURCE_SHORTAGE 4 /* 0x4 */
126
127 #define SSH2_EXTENDED_DATA_STDERR 1 /* 0x1 */
128
129 /*
130 * Various remote-bug flags.
131 */
132 #define BUG_CHOKES_ON_SSH1_IGNORE 1
133 #define BUG_SSH2_HMAC 2
134
135 #define GET_32BIT(cp) \
136 (((unsigned long)(unsigned char)(cp)[0] << 24) | \
137 ((unsigned long)(unsigned char)(cp)[1] << 16) | \
138 ((unsigned long)(unsigned char)(cp)[2] << 8) | \
139 ((unsigned long)(unsigned char)(cp)[3]))
140
141 #define PUT_32BIT(cp, value) { \
142 (cp)[0] = (unsigned char)((value) >> 24); \
143 (cp)[1] = (unsigned char)((value) >> 16); \
144 (cp)[2] = (unsigned char)((value) >> 8); \
145 (cp)[3] = (unsigned char)(value); }
146
147 enum { PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR, PKT_BIGNUM };
148
149 /* Coroutine mechanics for the sillier bits of the code */
150 #define crBegin1 static int crLine = 0;
151 #define crBegin2 switch(crLine) { case 0:;
152 #define crBegin crBegin1; crBegin2;
153 #define crFinish(z) } crLine = 0; return (z)
154 #define crFinishV } crLine = 0; return
155 #define crReturn(z) \
156 do {\
157 crLine=__LINE__; return (z); case __LINE__:;\
158 } while (0)
159 #define crReturnV \
160 do {\
161 crLine=__LINE__; return; case __LINE__:;\
162 } while (0)
163 #define crStop(z) do{ crLine = 0; return (z); }while(0)
164 #define crStopV do{ crLine = 0; return; }while(0)
165 #define crWaitUntil(c) do { crReturn(0); } while (!(c))
166 #define crWaitUntilV(c) do { crReturnV; } while (!(c))
167
168 extern char *x11_init (Socket *, char *, void *);
169 extern void x11_close (Socket);
170 extern void x11_send (Socket , char *, int);
171 extern void x11_invent_auth(char *, int, char *, int);
172
173 /*
174 * Ciphers for SSH2. We miss out single-DES because it isn't
175 * supported; also 3DES and Blowfish are both done differently from
176 * SSH1. (3DES uses outer chaining; Blowfish has the opposite
177 * endianness and different-sized keys.)
178 */
179 const static struct ssh2_ciphers *ciphers[] = {
180 &ssh2_aes,
181 &ssh2_blowfish,
182 &ssh2_3des,
183 };
184
185 const static struct ssh_kex *kex_algs[] = {
186 &ssh_diffiehellman_gex,
187 &ssh_diffiehellman };
188
189 const static struct ssh_signkey *hostkey_algs[] = { &ssh_rsa, &ssh_dss };
190
191 static void nullmac_key(unsigned char *key) { }
192 static void nullmac_generate(unsigned char *blk, int len, unsigned long seq) { }
193 static int nullmac_verify(unsigned char *blk, int len, unsigned long seq) { return 1; }
194 const static struct ssh_mac ssh_mac_none = {
195 nullmac_key, nullmac_key, nullmac_generate, nullmac_verify, "none", 0
196 };
197 const static struct ssh_mac *macs[] = {
198 &ssh_sha1, &ssh_md5, &ssh_mac_none };
199 const static struct ssh_mac *buggymacs[] = {
200 &ssh_sha1_buggy, &ssh_md5, &ssh_mac_none };
201
202 static void ssh_comp_none_init(void) { }
203 static int ssh_comp_none_block(unsigned char *block, int len,
204 unsigned char **outblock, int *outlen) {
205 return 0;
206 }
207 static int ssh_comp_none_disable(void) { return 0; }
208 const static struct ssh_compress ssh_comp_none = {
209 "none",
210 ssh_comp_none_init, ssh_comp_none_block,
211 ssh_comp_none_init, ssh_comp_none_block,
212 ssh_comp_none_disable
213 };
214 extern const struct ssh_compress ssh_zlib;
215 const static struct ssh_compress *compressions[] = {
216 &ssh_zlib, &ssh_comp_none };
217
218 enum { /* channel types */
219 CHAN_MAINSESSION,
220 CHAN_X11,
221 CHAN_AGENT,
222 };
223
224 /*
225 * 2-3-4 tree storing channels.
226 */
227 struct ssh_channel {
228 unsigned remoteid, localid;
229 int type;
230 int closes;
231 struct ssh2_data_channel {
232 unsigned char *outbuffer;
233 unsigned outbuflen, outbufsize;
234 unsigned remwindow, remmaxpkt;
235 } v2;
236 union {
237 struct ssh_agent_channel {
238 unsigned char *message;
239 unsigned char msglen[4];
240 int lensofar, totallen;
241 } a;
242 struct ssh_x11_channel {
243 Socket s;
244 } x11;
245 } u;
246 };
247
248 struct Packet {
249 long length;
250 int type;
251 unsigned char *data;
252 unsigned char *body;
253 long savedpos;
254 long maxlen;
255 };
256
257 static SHA_State exhash, exhashbase;
258
259 static Socket s = NULL;
260
261 static unsigned char session_key[32];
262 static int ssh1_compressing;
263 static int ssh1_remote_protoflags;
264 static int ssh1_local_protoflags;
265 static int ssh_agentfwd_enabled;
266 static int ssh_X11_fwd_enabled;
267 static int ssh_remote_bugs;
268 static const struct ssh_cipher *cipher = NULL;
269 static const struct ssh2_cipher *cscipher = NULL;
270 static const struct ssh2_cipher *sccipher = NULL;
271 static const struct ssh_mac *csmac = NULL;
272 static const struct ssh_mac *scmac = NULL;
273 static const struct ssh_compress *cscomp = NULL;
274 static const struct ssh_compress *sccomp = NULL;
275 static const struct ssh_kex *kex = NULL;
276 static const struct ssh_signkey *hostkey = NULL;
277 static unsigned char ssh2_session_id[20];
278 int (*ssh_get_line)(const char *prompt, char *str, int maxlen,
279 int is_pw) = NULL;
280
281 static char *savedhost;
282 static int savedport;
283 static int ssh_send_ok;
284 static int ssh_echoing, ssh_editing;
285
286 static tree234 *ssh_channels; /* indexed by local id */
287 static struct ssh_channel *mainchan; /* primary session channel */
288
289 static enum {
290 SSH_STATE_PREPACKET,
291 SSH_STATE_BEFORE_SIZE,
292 SSH_STATE_INTERMED,
293 SSH_STATE_SESSION,
294 SSH_STATE_CLOSED
295 } ssh_state = SSH_STATE_PREPACKET;
296
297 static int size_needed = FALSE, eof_needed = FALSE;
298
299 static struct Packet pktin = { 0, 0, NULL, NULL, 0 };
300 static struct Packet pktout = { 0, 0, NULL, NULL, 0 };
301 static unsigned char *deferred_send_data = NULL;
302 static int deferred_len = 0, deferred_size = 0;
303
304 static int ssh_version;
305 static void (*ssh_protocol)(unsigned char *in, int inlen, int ispkt);
306 static void ssh1_protocol(unsigned char *in, int inlen, int ispkt);
307 static void ssh2_protocol(unsigned char *in, int inlen, int ispkt);
308 static void ssh_size(void);
309 static void ssh_special (Telnet_Special);
310 static void ssh2_try_send(struct ssh_channel *c);
311 static void ssh2_add_channel_data(struct ssh_channel *c, char *buf, int len);
312
313 static int (*s_rdpkt)(unsigned char **data, int *datalen);
314
315 static struct rdpkt1_state_tag {
316 long len, pad, biglen, to_read;
317 unsigned long realcrc, gotcrc;
318 unsigned char *p;
319 int i;
320 int chunk;
321 } rdpkt1_state;
322
323 static struct rdpkt2_state_tag {
324 long len, pad, payload, packetlen, maclen;
325 int i;
326 int cipherblk;
327 unsigned long incoming_sequence;
328 } rdpkt2_state;
329
330 static int ssh_channelcmp(void *av, void *bv) {
331 struct ssh_channel *a = (struct ssh_channel *)av;
332 struct ssh_channel *b = (struct ssh_channel *)bv;
333 if (a->localid < b->localid) return -1;
334 if (a->localid > b->localid) return +1;
335 return 0;
336 }
337 static int ssh_channelfind(void *av, void *bv) {
338 unsigned *a = (unsigned *)av;
339 struct ssh_channel *b = (struct ssh_channel *)bv;
340 if (*a < b->localid) return -1;
341 if (*a > b->localid) return +1;
342 return 0;
343 }
344
345 static void c_write (char *buf, int len) {
346 if ((flags & FLAG_STDERR)) {
347 int i;
348 for (i = 0; i < len; i++)
349 if (buf[i] != '\r')
350 fputc(buf[i], stderr);
351 return;
352 }
353 from_backend(1, buf, len);
354 }
355
356 static void c_write_untrusted(char *buf, int len) {
357 int i;
358 for (i = 0; i < len; i++) {
359 if (buf[i] == '\n')
360 c_write("\r\n", 2);
361 else if ((buf[i] & 0x60) || (buf[i] == '\r'))
362 c_write(buf+i, 1);
363 }
364 }
365
366 static void c_write_str (char *buf) {
367 c_write(buf, strlen(buf));
368 }
369
370 /*
371 * Collect incoming data in the incoming packet buffer.
372 * Decipher and verify the packet when it is completely read.
373 * Drop SSH1_MSG_DEBUG and SSH1_MSG_IGNORE packets.
374 * Update the *data and *datalen variables.
375 * Return the additional nr of bytes needed, or 0 when
376 * a complete packet is available.
377 */
378 static int ssh1_rdpkt(unsigned char **data, int *datalen)
379 {
380 struct rdpkt1_state_tag *st = &rdpkt1_state;
381
382 crBegin;
383
384 next_packet:
385
386 pktin.type = 0;
387 pktin.length = 0;
388
389 for (st->i = st->len = 0; st->i < 4; st->i++) {
390 while ((*datalen) == 0)
391 crReturn(4-st->i);
392 st->len = (st->len << 8) + **data;
393 (*data)++, (*datalen)--;
394 }
395
396 #ifdef FWHACK
397 if (st->len == 0x52656d6f) { /* "Remo"te server has closed ... */
398 st->len = 0x300; /* big enough to carry to end */
399 }
400 #endif
401
402 st->pad = 8 - (st->len % 8);
403 st->biglen = st->len + st->pad;
404 pktin.length = st->len - 5;
405
406 if (pktin.maxlen < st->biglen) {
407 pktin.maxlen = st->biglen;
408 pktin.data = (pktin.data == NULL ? smalloc(st->biglen+APIEXTRA) :
409 srealloc(pktin.data, st->biglen+APIEXTRA));
410 if (!pktin.data)
411 fatalbox("Out of memory");
412 }
413
414 st->to_read = st->biglen;
415 st->p = pktin.data;
416 while (st->to_read > 0) {
417 st->chunk = st->to_read;
418 while ((*datalen) == 0)
419 crReturn(st->to_read);
420 if (st->chunk > (*datalen))
421 st->chunk = (*datalen);
422 memcpy(st->p, *data, st->chunk);
423 *data += st->chunk;
424 *datalen -= st->chunk;
425 st->p += st->chunk;
426 st->to_read -= st->chunk;
427 }
428
429 if (cipher)
430 cipher->decrypt(pktin.data, st->biglen);
431 #if 0
432 debug(("Got packet len=%d pad=%d\r\n", st->len, st->pad));
433 for (st->i = 0; st->i < st->biglen; st->i++)
434 debug((" %02x", (unsigned char)pktin.data[st->i]));
435 debug(("\r\n"));
436 #endif
437
438 st->realcrc = crc32(pktin.data, st->biglen-4);
439 st->gotcrc = GET_32BIT(pktin.data+st->biglen-4);
440 if (st->gotcrc != st->realcrc) {
441 bombout(("Incorrect CRC received on packet"));
442 crReturn(0);
443 }
444
445 pktin.body = pktin.data + st->pad + 1;
446
447 if (ssh1_compressing) {
448 unsigned char *decompblk;
449 int decomplen;
450 #if 0
451 {
452 int i;
453 debug(("Packet payload pre-decompression:\n"));
454 for (i = -1; i < pktin.length; i++)
455 debug((" %02x", (unsigned char)pktin.body[i]));
456 debug(("\r\n"));
457 }
458 #endif
459 zlib_decompress_block(pktin.body-1, pktin.length+1,
460 &decompblk, &decomplen);
461
462 if (pktin.maxlen < st->pad + decomplen) {
463 pktin.maxlen = st->pad + decomplen;
464 pktin.data = srealloc(pktin.data, pktin.maxlen+APIEXTRA);
465 pktin.body = pktin.data + st->pad + 1;
466 if (!pktin.data)
467 fatalbox("Out of memory");
468 }
469
470 memcpy(pktin.body-1, decompblk, decomplen);
471 sfree(decompblk);
472 pktin.length = decomplen-1;
473 #if 0
474 {
475 int i;
476 debug(("Packet payload post-decompression:\n"));
477 for (i = -1; i < pktin.length; i++)
478 debug((" %02x", (unsigned char)pktin.body[i]));
479 debug(("\r\n"));
480 }
481 #endif
482 }
483
484 if (pktin.type == SSH1_SMSG_STDOUT_DATA ||
485 pktin.type == SSH1_SMSG_STDERR_DATA ||
486 pktin.type == SSH1_MSG_DEBUG ||
487 pktin.type == SSH1_SMSG_AUTH_TIS_CHALLENGE ||
488 pktin.type == SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
489 long strlen = GET_32BIT(pktin.body);
490 if (strlen + 4 != pktin.length) {
491 bombout(("Received data packet with bogus string length"));
492 crReturn(0);
493 }
494 }
495
496 pktin.type = pktin.body[-1];
497
498 if (pktin.type == SSH1_MSG_DEBUG) {
499 /* log debug message */
500 char buf[80];
501 int strlen = GET_32BIT(pktin.body);
502 strcpy(buf, "Remote: ");
503 if (strlen > 70) strlen = 70;
504 memcpy(buf+8, pktin.body+4, strlen);
505 buf[8+strlen] = '\0';
506 logevent(buf);
507 goto next_packet;
508 } else if (pktin.type == SSH1_MSG_IGNORE) {
509 /* do nothing */
510 goto next_packet;
511 }
512
513 crFinish(0);
514 }
515
516 static int ssh2_rdpkt(unsigned char **data, int *datalen)
517 {
518 struct rdpkt2_state_tag *st = &rdpkt2_state;
519
520 crBegin;
521
522 next_packet:
523 pktin.type = 0;
524 pktin.length = 0;
525 if (sccipher)
526 st->cipherblk = sccipher->blksize;
527 else
528 st->cipherblk = 8;
529 if (st->cipherblk < 8)
530 st->cipherblk = 8;
531
532 if (pktin.maxlen < st->cipherblk) {
533 pktin.maxlen = st->cipherblk;
534 pktin.data = (pktin.data == NULL ? smalloc(st->cipherblk+APIEXTRA) :
535 srealloc(pktin.data, st->cipherblk+APIEXTRA));
536 if (!pktin.data)
537 fatalbox("Out of memory");
538 }
539
540 /*
541 * Acquire and decrypt the first block of the packet. This will
542 * contain the length and padding details.
543 */
544 for (st->i = st->len = 0; st->i < st->cipherblk; st->i++) {
545 while ((*datalen) == 0)
546 crReturn(st->cipherblk-st->i);
547 pktin.data[st->i] = *(*data)++;
548 (*datalen)--;
549 }
550 #ifdef FWHACK
551 if (!memcmp(pktin.data, "Remo", 4)) {/* "Remo"te server has closed ... */
552 /* FIXME */
553 }
554 #endif
555 if (sccipher)
556 sccipher->decrypt(pktin.data, st->cipherblk);
557
558 /*
559 * Now get the length and padding figures.
560 */
561 st->len = GET_32BIT(pktin.data);
562 st->pad = pktin.data[4];
563
564 /*
565 * This enables us to deduce the payload length.
566 */
567 st->payload = st->len - st->pad - 1;
568
569 pktin.length = st->payload + 5;
570
571 /*
572 * So now we can work out the total packet length.
573 */
574 st->packetlen = st->len + 4;
575 st->maclen = scmac ? scmac->len : 0;
576
577 /*
578 * Adjust memory allocation if packet is too big.
579 */
580 if (pktin.maxlen < st->packetlen+st->maclen) {
581 pktin.maxlen = st->packetlen+st->maclen;
582 pktin.data = (pktin.data == NULL ? smalloc(pktin.maxlen+APIEXTRA) :
583 srealloc(pktin.data, pktin.maxlen+APIEXTRA));
584 if (!pktin.data)
585 fatalbox("Out of memory");
586 }
587
588 /*
589 * Read and decrypt the remainder of the packet.
590 */
591 for (st->i = st->cipherblk; st->i < st->packetlen + st->maclen; st->i++) {
592 while ((*datalen) == 0)
593 crReturn(st->packetlen + st->maclen - st->i);
594 pktin.data[st->i] = *(*data)++;
595 (*datalen)--;
596 }
597 /* Decrypt everything _except_ the MAC. */
598 if (sccipher)
599 sccipher->decrypt(pktin.data + st->cipherblk,
600 st->packetlen - st->cipherblk);
601
602 #if 0
603 debug(("Got packet len=%d pad=%d\r\n", st->len, st->pad));
604 for (st->i = 0; st->i < st->packetlen; st->i++)
605 debug((" %02x", (unsigned char)pktin.data[st->i]));
606 debug(("\r\n"));
607 #endif
608
609 /*
610 * Check the MAC.
611 */
612 if (scmac && !scmac->verify(pktin.data, st->len+4, st->incoming_sequence)) {
613 bombout(("Incorrect MAC received on packet"));
614 crReturn(0);
615 }
616 st->incoming_sequence++; /* whether or not we MACed */
617
618 /*
619 * Decompress packet payload.
620 */
621 {
622 unsigned char *newpayload;
623 int newlen;
624 if (sccomp && sccomp->decompress(pktin.data+5, pktin.length-5,
625 &newpayload, &newlen)) {
626 if (pktin.maxlen < newlen+5) {
627 pktin.maxlen = newlen+5;
628 pktin.data = (pktin.data == NULL ? smalloc(pktin.maxlen+APIEXTRA) :
629 srealloc(pktin.data, pktin.maxlen+APIEXTRA));
630 if (!pktin.data)
631 fatalbox("Out of memory");
632 }
633 pktin.length = 5 + newlen;
634 memcpy(pktin.data+5, newpayload, newlen);
635 #if 0
636 debug(("Post-decompression payload:\r\n"));
637 for (st->i = 0; st->i < newlen; st->i++)
638 debug((" %02x", (unsigned char)pktin.data[5+st->i]));
639 debug(("\r\n"));
640 #endif
641
642 sfree(newpayload);
643 }
644 }
645
646 pktin.savedpos = 6;
647 pktin.type = pktin.data[5];
648
649 if (pktin.type == SSH2_MSG_IGNORE || pktin.type == SSH2_MSG_DEBUG)
650 goto next_packet; /* FIXME: print DEBUG message */
651
652 crFinish(0);
653 }
654
655 static void ssh1_pktout_size(int len) {
656 int pad, biglen;
657
658 len += 5; /* type and CRC */
659 pad = 8 - (len%8);
660 biglen = len + pad;
661
662 pktout.length = len-5;
663 if (pktout.maxlen < biglen) {
664 pktout.maxlen = biglen;
665 #ifdef MSCRYPTOAPI
666 /* Allocate enough buffer space for extra block
667 * for MS CryptEncrypt() */
668 pktout.data = (pktout.data == NULL ? smalloc(biglen+12) :
669 srealloc(pktout.data, biglen+12));
670 #else
671 pktout.data = (pktout.data == NULL ? smalloc(biglen+4) :
672 srealloc(pktout.data, biglen+4));
673 #endif
674 if (!pktout.data)
675 fatalbox("Out of memory");
676 }
677 pktout.body = pktout.data+4+pad+1;
678 }
679
680 static void s_wrpkt_start(int type, int len) {
681 ssh1_pktout_size(len);
682 pktout.type = type;
683 }
684
685 static int s_wrpkt_prepare(void) {
686 int pad, len, biglen, i;
687 unsigned long crc;
688
689 pktout.body[-1] = pktout.type;
690
691 #if 0
692 debug(("Packet payload pre-compression:\n"));
693 for (i = -1; i < pktout.length; i++)
694 debug((" %02x", (unsigned char)pktout.body[i]));
695 debug(("\r\n"));
696 #endif
697
698 if (ssh1_compressing) {
699 unsigned char *compblk;
700 int complen;
701 zlib_compress_block(pktout.body-1, pktout.length+1,
702 &compblk, &complen);
703 ssh1_pktout_size(complen-1);
704 memcpy(pktout.body-1, compblk, complen);
705 sfree(compblk);
706 #if 0
707 debug(("Packet payload post-compression:\n"));
708 for (i = -1; i < pktout.length; i++)
709 debug((" %02x", (unsigned char)pktout.body[i]));
710 debug(("\r\n"));
711 #endif
712 }
713
714 len = pktout.length + 5; /* type and CRC */
715 pad = 8 - (len%8);
716 biglen = len + pad;
717
718 for (i=0; i<pad; i++)
719 pktout.data[i+4] = random_byte();
720 crc = crc32(pktout.data+4, biglen-4);
721 PUT_32BIT(pktout.data+biglen, crc);
722 PUT_32BIT(pktout.data, len);
723
724 #if 0
725 debug(("Sending packet len=%d\r\n", biglen+4));
726 for (i = 0; i < biglen+4; i++)
727 debug((" %02x", (unsigned char)pktout.data[i]));
728 debug(("\r\n"));
729 #endif
730 if (cipher)
731 cipher->encrypt(pktout.data+4, biglen);
732
733 return biglen+4;
734 }
735
736 static void s_wrpkt(void) {
737 int len;
738 len = s_wrpkt_prepare();
739 sk_write(s, pktout.data, len);
740 }
741
742 static void s_wrpkt_defer(void) {
743 int len;
744 len = s_wrpkt_prepare();
745 if (deferred_len + len > deferred_size) {
746 deferred_size = deferred_len + len + 128;
747 deferred_send_data = srealloc(deferred_send_data, deferred_size);
748 }
749 memcpy(deferred_send_data+deferred_len, pktout.data, len);
750 deferred_len += len;
751 }
752
753 /*
754 * Construct a packet with the specified contents.
755 */
756 static void construct_packet(int pkttype, va_list ap1, va_list ap2)
757 {
758 unsigned char *p, *argp, argchar;
759 unsigned long argint;
760 int pktlen, argtype, arglen;
761 Bignum bn;
762
763 pktlen = 0;
764 while ((argtype = va_arg(ap1, int)) != PKT_END) {
765 switch (argtype) {
766 case PKT_INT:
767 (void) va_arg(ap1, int);
768 pktlen += 4;
769 break;
770 case PKT_CHAR:
771 (void) va_arg(ap1, char);
772 pktlen++;
773 break;
774 case PKT_DATA:
775 (void) va_arg(ap1, unsigned char *);
776 arglen = va_arg(ap1, int);
777 pktlen += arglen;
778 break;
779 case PKT_STR:
780 argp = va_arg(ap1, unsigned char *);
781 arglen = strlen(argp);
782 pktlen += 4 + arglen;
783 break;
784 case PKT_BIGNUM:
785 bn = va_arg(ap1, Bignum);
786 pktlen += ssh1_bignum_length(bn);
787 break;
788 default:
789 assert(0);
790 }
791 }
792
793 s_wrpkt_start(pkttype, pktlen);
794 p = pktout.body;
795
796 while ((argtype = va_arg(ap2, int)) != PKT_END) {
797 switch (argtype) {
798 case PKT_INT:
799 argint = va_arg(ap2, int);
800 PUT_32BIT(p, argint);
801 p += 4;
802 break;
803 case PKT_CHAR:
804 argchar = va_arg(ap2, unsigned char);
805 *p = argchar;
806 p++;
807 break;
808 case PKT_DATA:
809 argp = va_arg(ap2, unsigned char *);
810 arglen = va_arg(ap2, int);
811 memcpy(p, argp, arglen);
812 p += arglen;
813 break;
814 case PKT_STR:
815 argp = va_arg(ap2, unsigned char *);
816 arglen = strlen(argp);
817 PUT_32BIT(p, arglen);
818 memcpy(p + 4, argp, arglen);
819 p += 4 + arglen;
820 break;
821 case PKT_BIGNUM:
822 bn = va_arg(ap2, Bignum);
823 p += ssh1_write_bignum(p, bn);
824 break;
825 }
826 }
827 }
828
829 static void send_packet(int pkttype, ...) {
830 va_list ap1, ap2;
831 va_start(ap1, pkttype);
832 va_start(ap2, pkttype);
833 construct_packet(pkttype, ap1, ap2);
834 s_wrpkt();
835 }
836
837 static void defer_packet(int pkttype, ...) {
838 va_list ap1, ap2;
839 va_start(ap1, pkttype);
840 va_start(ap2, pkttype);
841 construct_packet(pkttype, ap1, ap2);
842 s_wrpkt_defer();
843 }
844
845 static int ssh_versioncmp(char *a, char *b) {
846 char *ae, *be;
847 unsigned long av, bv;
848
849 av = strtoul(a, &ae, 10);
850 bv = strtoul(b, &be, 10);
851 if (av != bv) return (av < bv ? -1 : +1);
852 if (*ae == '.') ae++;
853 if (*be == '.') be++;
854 av = strtoul(ae, &ae, 10);
855 bv = strtoul(be, &be, 10);
856 if (av != bv) return (av < bv ? -1 : +1);
857 return 0;
858 }
859
860
861 /*
862 * Utility routines for putting an SSH-protocol `string' and
863 * `uint32' into a SHA state.
864 */
865 #include <stdio.h>
866 static void sha_string(SHA_State *s, void *str, int len) {
867 unsigned char lenblk[4];
868 PUT_32BIT(lenblk, len);
869 SHA_Bytes(s, lenblk, 4);
870 SHA_Bytes(s, str, len);
871 }
872
873 static void sha_uint32(SHA_State *s, unsigned i) {
874 unsigned char intblk[4];
875 PUT_32BIT(intblk, i);
876 SHA_Bytes(s, intblk, 4);
877 }
878
879 /*
880 * SSH2 packet construction functions.
881 */
882 static void ssh2_pkt_ensure(int length) {
883 if (pktout.maxlen < length) {
884 pktout.maxlen = length + 256;
885 pktout.data = (pktout.data == NULL ? smalloc(pktout.maxlen+APIEXTRA) :
886 srealloc(pktout.data, pktout.maxlen+APIEXTRA));
887 if (!pktout.data)
888 fatalbox("Out of memory");
889 }
890 }
891 static void ssh2_pkt_adddata(void *data, int len) {
892 pktout.length += len;
893 ssh2_pkt_ensure(pktout.length);
894 memcpy(pktout.data+pktout.length-len, data, len);
895 }
896 static void ssh2_pkt_addbyte(unsigned char byte) {
897 ssh2_pkt_adddata(&byte, 1);
898 }
899 static void ssh2_pkt_init(int pkt_type) {
900 pktout.length = 5;
901 ssh2_pkt_addbyte((unsigned char)pkt_type);
902 }
903 static void ssh2_pkt_addbool(unsigned char value) {
904 ssh2_pkt_adddata(&value, 1);
905 }
906 static void ssh2_pkt_adduint32(unsigned long value) {
907 unsigned char x[4];
908 PUT_32BIT(x, value);
909 ssh2_pkt_adddata(x, 4);
910 }
911 static void ssh2_pkt_addstring_start(void) {
912 ssh2_pkt_adduint32(0);
913 pktout.savedpos = pktout.length;
914 }
915 static void ssh2_pkt_addstring_str(char *data) {
916 ssh2_pkt_adddata(data, strlen(data));
917 PUT_32BIT(pktout.data + pktout.savedpos - 4,
918 pktout.length - pktout.savedpos);
919 }
920 static void ssh2_pkt_addstring_data(char *data, int len) {
921 ssh2_pkt_adddata(data, len);
922 PUT_32BIT(pktout.data + pktout.savedpos - 4,
923 pktout.length - pktout.savedpos);
924 }
925 static void ssh2_pkt_addstring(char *data) {
926 ssh2_pkt_addstring_start();
927 ssh2_pkt_addstring_str(data);
928 }
929 static char *ssh2_mpint_fmt(Bignum b, int *len) {
930 unsigned char *p;
931 int i, n = (ssh1_bignum_bitcount(b)+7)/8;
932 p = smalloc(n + 1);
933 if (!p)
934 fatalbox("out of memory");
935 p[0] = 0;
936 for (i = 1; i <= n; i++)
937 p[i] = bignum_byte(b, n-i);
938 i = 0;
939 while (i <= n && p[i] == 0 && (p[i+1] & 0x80) == 0)
940 i++;
941 memmove(p, p+i, n+1-i);
942 *len = n+1-i;
943 return p;
944 }
945 static void ssh2_pkt_addmp(Bignum b) {
946 unsigned char *p;
947 int len;
948 p = ssh2_mpint_fmt(b, &len);
949 ssh2_pkt_addstring_start();
950 ssh2_pkt_addstring_data(p, len);
951 sfree(p);
952 }
953
954 /*
955 * Construct an SSH2 final-form packet: compress it, encrypt it,
956 * put the MAC on it. Final packet, ready to be sent, is stored in
957 * pktout.data. Total length is returned.
958 */
959 static int ssh2_pkt_construct(void) {
960 int cipherblk, maclen, padding, i;
961 static unsigned long outgoing_sequence = 0;
962
963 /*
964 * Compress packet payload.
965 */
966 #if 0
967 debug(("Pre-compression payload:\r\n"));
968 for (i = 5; i < pktout.length; i++)
969 debug((" %02x", (unsigned char)pktout.data[i]));
970 debug(("\r\n"));
971 #endif
972 {
973 unsigned char *newpayload;
974 int newlen;
975 if (cscomp && cscomp->compress(pktout.data+5, pktout.length-5,
976 &newpayload, &newlen)) {
977 pktout.length = 5;
978 ssh2_pkt_adddata(newpayload, newlen);
979 sfree(newpayload);
980 }
981 }
982
983 /*
984 * Add padding. At least four bytes, and must also bring total
985 * length (minus MAC) up to a multiple of the block size.
986 */
987 cipherblk = cscipher ? cscipher->blksize : 8; /* block size */
988 cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */
989 padding = 4;
990 padding += (cipherblk - (pktout.length + padding) % cipherblk) % cipherblk;
991 maclen = csmac ? csmac->len : 0;
992 ssh2_pkt_ensure(pktout.length + padding + maclen);
993 pktout.data[4] = padding;
994 for (i = 0; i < padding; i++)
995 pktout.data[pktout.length + i] = random_byte();
996 PUT_32BIT(pktout.data, pktout.length + padding - 4);
997 if (csmac)
998 csmac->generate(pktout.data, pktout.length + padding,
999 outgoing_sequence);
1000 outgoing_sequence++; /* whether or not we MACed */
1001
1002 #if 0
1003 debug(("Sending packet len=%d\r\n", pktout.length+padding));
1004 for (i = 0; i < pktout.length+padding; i++)
1005 debug((" %02x", (unsigned char)pktout.data[i]));
1006 debug(("\r\n"));
1007 #endif
1008
1009 if (cscipher)
1010 cscipher->encrypt(pktout.data, pktout.length + padding);
1011
1012 /* Ready-to-send packet starts at pktout.data. We return length. */
1013 return pktout.length + padding + maclen;
1014 }
1015
1016 /*
1017 * Construct and send an SSH2 packet immediately.
1018 */
1019 static void ssh2_pkt_send(void) {
1020 int len = ssh2_pkt_construct();
1021 sk_write(s, pktout.data, len);
1022 }
1023
1024 /*
1025 * Construct an SSH2 packet and add it to a deferred data block.
1026 * Useful for sending multiple packets in a single sk_write() call,
1027 * to prevent a traffic-analysing listener from being able to work
1028 * out the length of any particular packet (such as the password
1029 * packet).
1030 *
1031 * Note that because SSH2 sequence-numbers its packets, this can
1032 * NOT be used as an m4-style `defer' allowing packets to be
1033 * constructed in one order and sent in another.
1034 */
1035 static void ssh2_pkt_defer(void) {
1036 int len = ssh2_pkt_construct();
1037 if (deferred_len + len > deferred_size) {
1038 deferred_size = deferred_len + len + 128;
1039 deferred_send_data = srealloc(deferred_send_data, deferred_size);
1040 }
1041 memcpy(deferred_send_data+deferred_len, pktout.data, len);
1042 deferred_len += len;
1043 }
1044
1045 /*
1046 * Send the whole deferred data block constructed by
1047 * ssh2_pkt_defer() or SSH1's defer_packet().
1048 */
1049 static void ssh_pkt_defersend(void) {
1050 sk_write(s, deferred_send_data, deferred_len);
1051 deferred_len = deferred_size = 0;
1052 sfree(deferred_send_data);
1053 deferred_send_data = NULL;
1054 }
1055
1056 #if 0
1057 void bndebug(char *string, Bignum b) {
1058 unsigned char *p;
1059 int i, len;
1060 p = ssh2_mpint_fmt(b, &len);
1061 debug(("%s", string));
1062 for (i = 0; i < len; i++)
1063 debug((" %02x", p[i]));
1064 debug(("\r\n"));
1065 sfree(p);
1066 }
1067 #endif
1068
1069 static void sha_mpint(SHA_State *s, Bignum b) {
1070 unsigned char *p;
1071 int len;
1072 p = ssh2_mpint_fmt(b, &len);
1073 sha_string(s, p, len);
1074 sfree(p);
1075 }
1076
1077 /*
1078 * SSH2 packet decode functions.
1079 */
1080 static unsigned long ssh2_pkt_getuint32(void) {
1081 unsigned long value;
1082 if (pktin.length - pktin.savedpos < 4)
1083 return 0; /* arrgh, no way to decline (FIXME?) */
1084 value = GET_32BIT(pktin.data+pktin.savedpos);
1085 pktin.savedpos += 4;
1086 return value;
1087 }
1088 static int ssh2_pkt_getbool(void) {
1089 unsigned long value;
1090 if (pktin.length - pktin.savedpos < 1)
1091 return 0; /* arrgh, no way to decline (FIXME?) */
1092 value = pktin.data[pktin.savedpos] != 0;
1093 pktin.savedpos++;
1094 return value;
1095 }
1096 static void ssh2_pkt_getstring(char **p, int *length) {
1097 *p = NULL;
1098 if (pktin.length - pktin.savedpos < 4)
1099 return;
1100 *length = GET_32BIT(pktin.data+pktin.savedpos);
1101 pktin.savedpos += 4;
1102 if (pktin.length - pktin.savedpos < *length)
1103 return;
1104 *p = pktin.data+pktin.savedpos;
1105 pktin.savedpos += *length;
1106 }
1107 static Bignum ssh2_pkt_getmp(void) {
1108 char *p;
1109 int length;
1110 Bignum b;
1111
1112 ssh2_pkt_getstring(&p, &length);
1113 if (!p)
1114 return NULL;
1115 if (p[0] & 0x80) {
1116 bombout(("internal error: Can't handle negative mpints"));
1117 return NULL;
1118 }
1119 b = bignum_from_bytes(p, length);
1120 return b;
1121 }
1122
1123 /*
1124 * Examine the remote side's version string and compare it against
1125 * a list of known buggy implementations.
1126 */
1127 static void ssh_detect_bugs(char *vstring) {
1128 char *imp; /* pointer to implementation part */
1129 imp = vstring;
1130 imp += strcspn(imp, "-");
1131 if (*imp) imp++;
1132 imp += strcspn(imp, "-");
1133 if (*imp) imp++;
1134
1135 ssh_remote_bugs = 0;
1136
1137 if (!strcmp(imp, "1.2.18") || !strcmp(imp, "1.2.19") ||
1138 !strcmp(imp, "1.2.20") || !strcmp(imp, "1.2.21") ||
1139 !strcmp(imp, "1.2.22")) {
1140 /*
1141 * These versions don't support SSH1_MSG_IGNORE, so we have
1142 * to use a different defence against password length
1143 * sniffing.
1144 */
1145 ssh_remote_bugs |= BUG_CHOKES_ON_SSH1_IGNORE;
1146 logevent("We believe remote version has SSH1 ignore bug");
1147 }
1148
1149 if (!strncmp(imp, "2.1.0", 5) || !strncmp(imp, "2.0.", 4) ||
1150 !strncmp(imp, "2.2.0", 5) || !strncmp(imp, "2.3.0", 5) ||
1151 !strncmp(imp, "2.1 ", 4)) {
1152 /*
1153 * These versions have the HMAC bug.
1154 */
1155 ssh_remote_bugs |= BUG_SSH2_HMAC;
1156 logevent("We believe remote version has SSH2 HMAC bug");
1157 }
1158 }
1159
1160 static int do_ssh_init(unsigned char c) {
1161 static char vslen;
1162 static char version[10];
1163 static char *vstring;
1164 static int vstrsize;
1165 static char *vlog;
1166 static int i;
1167
1168 crBegin;
1169
1170 /* Search for the string "SSH-" in the input. */
1171 i = 0;
1172 while (1) {
1173 static const int transS[] = { 1, 2, 2, 1 };
1174 static const int transH[] = { 0, 0, 3, 0 };
1175 static const int transminus[] = { 0, 0, 0, -1 };
1176 if (c == 'S') i = transS[i];
1177 else if (c == 'H') i = transH[i];
1178 else if (c == '-') i = transminus[i];
1179 else i = 0;
1180 if (i < 0)
1181 break;
1182 crReturn(1); /* get another character */
1183 }
1184
1185 vstring = smalloc(16);
1186 vstrsize = 16;
1187 strcpy(vstring, "SSH-");
1188 vslen = 4;
1189 i = 0;
1190 while (1) {
1191 crReturn(1); /* get another char */
1192 if (vslen >= vstrsize-1) {
1193 vstrsize += 16;
1194 vstring = srealloc(vstring, vstrsize);
1195 }
1196 vstring[vslen++] = c;
1197 if (i >= 0) {
1198 if (c == '-') {
1199 version[i] = '\0';
1200 i = -1;
1201 } else if (i < sizeof(version)-1)
1202 version[i++] = c;
1203 }
1204 else if (c == '\n')
1205 break;
1206 }
1207
1208 ssh_agentfwd_enabled = FALSE;
1209 rdpkt2_state.incoming_sequence = 0;
1210
1211 vstring[vslen] = 0;
1212 vlog = smalloc(20 + vslen);
1213 sprintf(vlog, "Server version: %s", vstring);
1214 ssh_detect_bugs(vstring);
1215 vlog[strcspn(vlog, "\r\n")] = '\0';
1216 logevent(vlog);
1217 sfree(vlog);
1218
1219 /*
1220 * Server version "1.99" means we can choose whether we use v1
1221 * or v2 protocol. Choice is based on cfg.sshprot.
1222 */
1223 if (ssh_versioncmp(version, cfg.sshprot == 1 ? "2.0" : "1.99") >= 0) {
1224 /*
1225 * This is a v2 server. Begin v2 protocol.
1226 */
1227 char verstring[80], vlog[100];
1228 sprintf(verstring, "SSH-2.0-%s", sshver);
1229 SHA_Init(&exhashbase);
1230 /*
1231 * Hash our version string and their version string.
1232 */
1233 sha_string(&exhashbase, verstring, strlen(verstring));
1234 sha_string(&exhashbase, vstring, strcspn(vstring, "\r\n"));
1235 sprintf(vlog, "We claim version: %s", verstring);
1236 logevent(vlog);
1237 strcat(verstring, "\n");
1238 logevent("Using SSH protocol version 2");
1239 sk_write(s, verstring, strlen(verstring));
1240 ssh_protocol = ssh2_protocol;
1241 ssh_version = 2;
1242 s_rdpkt = ssh2_rdpkt;
1243 } else {
1244 /*
1245 * This is a v1 server. Begin v1 protocol.
1246 */
1247 char verstring[80], vlog[100];
1248 sprintf(verstring, "SSH-%s-%s",
1249 (ssh_versioncmp(version, "1.5") <= 0 ? version : "1.5"),
1250 sshver);
1251 sprintf(vlog, "We claim version: %s", verstring);
1252 logevent(vlog);
1253 strcat(verstring, "\n");
1254 logevent("Using SSH protocol version 1");
1255 sk_write(s, verstring, strlen(verstring));
1256 ssh_protocol = ssh1_protocol;
1257 ssh_version = 1;
1258 s_rdpkt = ssh1_rdpkt;
1259 }
1260 ssh_state = SSH_STATE_BEFORE_SIZE;
1261
1262 sfree(vstring);
1263
1264 crFinish(0);
1265 }
1266
1267 static void ssh_gotdata(unsigned char *data, int datalen)
1268 {
1269 crBegin;
1270
1271 /*
1272 * To begin with, feed the characters one by one to the
1273 * protocol initialisation / selection function do_ssh_init().
1274 * When that returns 0, we're done with the initial greeting
1275 * exchange and can move on to packet discipline.
1276 */
1277 while (1) {
1278 int ret;
1279 if (datalen == 0)
1280 crReturnV; /* more data please */
1281 ret = do_ssh_init(*data);
1282 data++; datalen--;
1283 if (ret == 0)
1284 break;
1285 }
1286
1287 /*
1288 * We emerge from that loop when the initial negotiation is
1289 * over and we have selected an s_rdpkt function. Now pass
1290 * everything to s_rdpkt, and then pass the resulting packets
1291 * to the proper protocol handler.
1292 */
1293 if (datalen == 0)
1294 crReturnV;
1295 while (1) {
1296 while (datalen > 0) {
1297 if ( s_rdpkt(&data, &datalen) == 0 ) {
1298 ssh_protocol(NULL, 0, 1);
1299 if (ssh_state == SSH_STATE_CLOSED) {
1300 return;
1301 }
1302 }
1303 }
1304 crReturnV;
1305 }
1306 crFinishV;
1307 }
1308
1309 static int ssh_closing (Plug plug, char *error_msg, int error_code, int calling_back) {
1310 ssh_state = SSH_STATE_CLOSED;
1311 sk_close(s);
1312 s = NULL;
1313 if (error_msg) {
1314 /* A socket error has occurred. */
1315 connection_fatal (error_msg);
1316 } else {
1317 /* Otherwise, the remote side closed the connection normally. */
1318 }
1319 return 0;
1320 }
1321
1322 static int ssh_receive(Plug plug, int urgent, char *data, int len) {
1323 ssh_gotdata (data, len);
1324 if (ssh_state == SSH_STATE_CLOSED) {
1325 if (s) {
1326 sk_close(s);
1327 s = NULL;
1328 }
1329 return 0;
1330 }
1331 return 1;
1332 }
1333
1334 /*
1335 * Connect to specified host and port.
1336 * Returns an error message, or NULL on success.
1337 * Also places the canonical host name into `realhost'.
1338 */
1339 static char *connect_to_host(char *host, int port, char **realhost)
1340 {
1341 static struct plug_function_table fn_table = {
1342 ssh_closing,
1343 ssh_receive
1344 }, *fn_table_ptr = &fn_table;
1345
1346 SockAddr addr;
1347 char *err;
1348 #ifdef FWHACK
1349 char *FWhost;
1350 int FWport;
1351 #endif
1352
1353 savedhost = smalloc(1+strlen(host));
1354 if (!savedhost)
1355 fatalbox("Out of memory");
1356 strcpy(savedhost, host);
1357
1358 if (port < 0)
1359 port = 22; /* default ssh port */
1360 savedport = port;
1361
1362 #ifdef FWHACK
1363 FWhost = host;
1364 FWport = port;
1365 host = FWSTR;
1366 port = 23;
1367 #endif
1368
1369 /*
1370 * Try to find host.
1371 */
1372 addr = sk_namelookup(host, realhost);
1373 if ( (err = sk_addr_error(addr)) )
1374 return err;
1375
1376 #ifdef FWHACK
1377 *realhost = FWhost;
1378 #endif
1379
1380 /*
1381 * Open socket.
1382 */
1383 s = sk_new(addr, port, 0, 1, &fn_table_ptr);
1384 if ( (err = sk_socket_error(s)) )
1385 return err;
1386
1387 #ifdef FWHACK
1388 sk_write(s, "connect ", 8);
1389 sk_write(s, FWhost, strlen(FWhost));
1390 {
1391 char buf[20];
1392 sprintf(buf, " %d\n", FWport);
1393 sk_write(s, buf, strlen(buf));
1394 }
1395 #endif
1396
1397 return NULL;
1398 }
1399
1400 /*
1401 * Handle the key exchange and user authentication phases.
1402 */
1403 static int do_ssh1_login(unsigned char *in, int inlen, int ispkt)
1404 {
1405 int i, j, len;
1406 unsigned char *rsabuf, *keystr1, *keystr2;
1407 unsigned char cookie[8];
1408 struct RSAKey servkey, hostkey;
1409 struct MD5Context md5c;
1410 static unsigned long supported_ciphers_mask, supported_auths_mask;
1411 static int tried_publickey;
1412 static unsigned char session_id[16];
1413 int cipher_type;
1414 static char username[100];
1415
1416 crBegin;
1417
1418 if (!ispkt) crWaitUntil(ispkt);
1419
1420 if (pktin.type != SSH1_SMSG_PUBLIC_KEY) {
1421 bombout(("Public key packet not received"));
1422 crReturn(0);
1423 }
1424
1425 logevent("Received public keys");
1426
1427 memcpy(cookie, pktin.body, 8);
1428
1429 i = makekey(pktin.body+8, &servkey, &keystr1, 0);
1430 j = makekey(pktin.body+8+i, &hostkey, &keystr2, 0);
1431
1432 /*
1433 * Log the host key fingerprint.
1434 */
1435 {
1436 char logmsg[80];
1437 logevent("Host key fingerprint is:");
1438 strcpy(logmsg, " ");
1439 hostkey.comment = NULL;
1440 rsa_fingerprint(logmsg+strlen(logmsg), sizeof(logmsg)-strlen(logmsg),
1441 &hostkey);
1442 logevent(logmsg);
1443 }
1444
1445 ssh1_remote_protoflags = GET_32BIT(pktin.body+8+i+j);
1446 supported_ciphers_mask = GET_32BIT(pktin.body+12+i+j);
1447 supported_auths_mask = GET_32BIT(pktin.body+16+i+j);
1448
1449 ssh1_local_protoflags = ssh1_remote_protoflags & SSH1_PROTOFLAGS_SUPPORTED;
1450 ssh1_local_protoflags |= SSH1_PROTOFLAG_SCREEN_NUMBER;
1451
1452 MD5Init(&md5c);
1453 MD5Update(&md5c, keystr2, hostkey.bytes);
1454 MD5Update(&md5c, keystr1, servkey.bytes);
1455 MD5Update(&md5c, pktin.body, 8);
1456 MD5Final(session_id, &md5c);
1457
1458 for (i=0; i<32; i++)
1459 session_key[i] = random_byte();
1460
1461 len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes);
1462
1463 rsabuf = smalloc(len);
1464 if (!rsabuf)
1465 fatalbox("Out of memory");
1466
1467 /*
1468 * Verify the host key.
1469 */
1470 {
1471 /*
1472 * First format the key into a string.
1473 */
1474 int len = rsastr_len(&hostkey);
1475 char fingerprint[100];
1476 char *keystr = smalloc(len);
1477 if (!keystr)
1478 fatalbox("Out of memory");
1479 rsastr_fmt(keystr, &hostkey);
1480 rsa_fingerprint(fingerprint, sizeof(fingerprint), &hostkey);
1481 verify_ssh_host_key(savedhost, savedport, "rsa", keystr, fingerprint);
1482 sfree(keystr);
1483 }
1484
1485 for (i=0; i<32; i++) {
1486 rsabuf[i] = session_key[i];
1487 if (i < 16)
1488 rsabuf[i] ^= session_id[i];
1489 }
1490
1491 if (hostkey.bytes > servkey.bytes) {
1492 rsaencrypt(rsabuf, 32, &servkey);
1493 rsaencrypt(rsabuf, servkey.bytes, &hostkey);
1494 } else {
1495 rsaencrypt(rsabuf, 32, &hostkey);
1496 rsaencrypt(rsabuf, hostkey.bytes, &servkey);
1497 }
1498
1499 logevent("Encrypted session key");
1500
1501 switch (cfg.cipher) {
1502 case CIPHER_BLOWFISH: cipher_type = SSH_CIPHER_BLOWFISH; break;
1503 case CIPHER_DES: cipher_type = SSH_CIPHER_DES; break;
1504 case CIPHER_3DES: cipher_type = SSH_CIPHER_3DES; break;
1505 case CIPHER_AES:
1506 c_write_str("AES not supported in SSH1, falling back to 3DES\r\n");
1507 cipher_type = SSH_CIPHER_3DES;
1508 break;
1509 }
1510 if ((supported_ciphers_mask & (1 << cipher_type)) == 0) {
1511 c_write_str("Selected cipher not supported, falling back to 3DES\r\n");
1512 cipher_type = SSH_CIPHER_3DES;
1513 }
1514 switch (cipher_type) {
1515 case SSH_CIPHER_3DES: logevent("Using 3DES encryption"); break;
1516 case SSH_CIPHER_DES: logevent("Using single-DES encryption"); break;
1517 case SSH_CIPHER_BLOWFISH: logevent("Using Blowfish encryption"); break;
1518 }
1519
1520 send_packet(SSH1_CMSG_SESSION_KEY,
1521 PKT_CHAR, cipher_type,
1522 PKT_DATA, cookie, 8,
1523 PKT_CHAR, (len*8) >> 8, PKT_CHAR, (len*8) & 0xFF,
1524 PKT_DATA, rsabuf, len,
1525 PKT_INT, ssh1_local_protoflags,
1526 PKT_END);
1527
1528 logevent("Trying to enable encryption...");
1529
1530 sfree(rsabuf);
1531
1532 cipher = cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 :
1533 cipher_type == SSH_CIPHER_DES ? &ssh_des :
1534 &ssh_3des;
1535 cipher->sesskey(session_key);
1536
1537 crWaitUntil(ispkt);
1538
1539 if (pktin.type != SSH1_SMSG_SUCCESS) {
1540 bombout(("Encryption not successfully enabled"));
1541 crReturn(0);
1542 }
1543
1544 logevent("Successfully started encryption");
1545
1546 fflush(stdout);
1547 {
1548 static int pos = 0;
1549 static char c;
1550 if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
1551 if (ssh_get_line) {
1552 if (!ssh_get_line("login as: ",
1553 username, sizeof(username), FALSE)) {
1554 /*
1555 * get_line failed to get a username.
1556 * Terminate.
1557 */
1558 logevent("No username provided. Abandoning session.");
1559 ssh_state = SSH_STATE_CLOSED;
1560 crReturn(1);
1561 }
1562 } else {
1563 c_write_str("login as: ");
1564 ssh_send_ok = 1;
1565 while (pos >= 0) {
1566 crWaitUntil(!ispkt);
1567 while (inlen--) switch (c = *in++) {
1568 case 10: case 13:
1569 username[pos] = 0;
1570 pos = -1;
1571 break;
1572 case 8: case 127:
1573 if (pos > 0) {
1574 c_write_str("\b \b");
1575 pos--;
1576 }
1577 break;
1578 case 21: case 27:
1579 while (pos > 0) {
1580 c_write_str("\b \b");
1581 pos--;
1582 }
1583 break;
1584 case 3: case 4:
1585 random_save_seed();
1586 exit(0);
1587 break;
1588 default:
1589 if (((c >= ' ' && c <= '~') ||
1590 ((unsigned char)c >= 160)) && pos < 40) {
1591 username[pos++] = c;
1592 c_write(&c, 1);
1593 }
1594 break;
1595 }
1596 }
1597 c_write_str("\r\n");
1598 username[strcspn(username, "\n\r")] = '\0';
1599 }
1600 } else {
1601 strncpy(username, cfg.username, 99);
1602 username[99] = '\0';
1603 }
1604
1605 send_packet(SSH1_CMSG_USER, PKT_STR, username, PKT_END);
1606 {
1607 char userlog[22+sizeof(username)];
1608 sprintf(userlog, "Sent username \"%s\"", username);
1609 logevent(userlog);
1610 if (flags & FLAG_INTERACTIVE &&
1611 (!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) {
1612 strcat(userlog, "\r\n");
1613 c_write_str(userlog);
1614 }
1615 }
1616 }
1617
1618 crWaitUntil(ispkt);
1619
1620 tried_publickey = 0;
1621
1622 while (pktin.type == SSH1_SMSG_FAILURE) {
1623 static char password[100];
1624 static char prompt[200];
1625 static int pos;
1626 static char c;
1627 static int pwpkt_type;
1628 /*
1629 * Show password prompt, having first obtained it via a TIS
1630 * or CryptoCard exchange if we're doing TIS or CryptoCard
1631 * authentication.
1632 */
1633 pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
1634 if (agent_exists()) {
1635 /*
1636 * Attempt RSA authentication using Pageant.
1637 */
1638 static unsigned char request[5], *response, *p;
1639 static int responselen;
1640 static int i, nkeys;
1641 static int authed = FALSE;
1642 void *r;
1643
1644 logevent("Pageant is running. Requesting keys.");
1645
1646 /* Request the keys held by the agent. */
1647 PUT_32BIT(request, 1);
1648 request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES;
1649 agent_query(request, 5, &r, &responselen);
1650 response = (unsigned char *)r;
1651 if (response && responselen >= 5 &&
1652 response[4] == SSH1_AGENT_RSA_IDENTITIES_ANSWER) {
1653 p = response + 5;
1654 nkeys = GET_32BIT(p); p += 4;
1655 { char buf[64]; sprintf(buf, "Pageant has %d SSH1 keys", nkeys);
1656 logevent(buf); }
1657 for (i = 0; i < nkeys; i++) {
1658 static struct RSAKey key;
1659 static Bignum challenge;
1660 static char *commentp;
1661 static int commentlen;
1662
1663 { char buf[64]; sprintf(buf, "Trying Pageant key #%d", i);
1664 logevent(buf); }
1665 p += 4;
1666 p += ssh1_read_bignum(p, &key.exponent);
1667 p += ssh1_read_bignum(p, &key.modulus);
1668 commentlen = GET_32BIT(p); p += 4;
1669 commentp = p; p += commentlen;
1670 send_packet(SSH1_CMSG_AUTH_RSA,
1671 PKT_BIGNUM, key.modulus, PKT_END);
1672 crWaitUntil(ispkt);
1673 if (pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
1674 logevent("Key refused");
1675 continue;
1676 }
1677 logevent("Received RSA challenge");
1678 ssh1_read_bignum(pktin.body, &challenge);
1679 {
1680 char *agentreq, *q, *ret;
1681 int len, retlen;
1682 len = 1 + 4; /* message type, bit count */
1683 len += ssh1_bignum_length(key.exponent);
1684 len += ssh1_bignum_length(key.modulus);
1685 len += ssh1_bignum_length(challenge);
1686 len += 16; /* session id */
1687 len += 4; /* response format */
1688 agentreq = smalloc(4 + len);
1689 PUT_32BIT(agentreq, len);
1690 q = agentreq + 4;
1691 *q++ = SSH1_AGENTC_RSA_CHALLENGE;
1692 PUT_32BIT(q, ssh1_bignum_bitcount(key.modulus));
1693 q += 4;
1694 q += ssh1_write_bignum(q, key.exponent);
1695 q += ssh1_write_bignum(q, key.modulus);
1696 q += ssh1_write_bignum(q, challenge);
1697 memcpy(q, session_id, 16); q += 16;
1698 PUT_32BIT(q, 1); /* response format */
1699 agent_query(agentreq, len+4, &ret, &retlen);
1700 sfree(agentreq);
1701 if (ret) {
1702 if (ret[4] == SSH1_AGENT_RSA_RESPONSE) {
1703 logevent("Sending Pageant's response");
1704 send_packet(SSH1_CMSG_AUTH_RSA_RESPONSE,
1705 PKT_DATA, ret+5, 16, PKT_END);
1706 sfree(ret);
1707 crWaitUntil(ispkt);
1708 if (pktin.type == SSH1_SMSG_SUCCESS) {
1709 logevent("Pageant's response accepted");
1710 if (flags & FLAG_VERBOSE) {
1711 c_write_str("Authenticated using RSA key \"");
1712 c_write(commentp, commentlen);
1713 c_write_str("\" from agent\r\n");
1714 }
1715 authed = TRUE;
1716 } else
1717 logevent("Pageant's response not accepted");
1718 } else {
1719 logevent("Pageant failed to answer challenge");
1720 sfree(ret);
1721 }
1722 } else {
1723 logevent("No reply received from Pageant");
1724 }
1725 }
1726 freebn(key.exponent);
1727 freebn(key.modulus);
1728 freebn(challenge);
1729 if (authed)
1730 break;
1731 }
1732 }
1733 if (authed)
1734 break;
1735 }
1736 if (*cfg.keyfile && !tried_publickey)
1737 pwpkt_type = SSH1_CMSG_AUTH_RSA;
1738
1739 if (pktin.type == SSH1_SMSG_FAILURE &&
1740 cfg.try_tis_auth &&
1741 (supported_auths_mask & (1<<SSH1_AUTH_TIS))) {
1742 pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
1743 logevent("Requested TIS authentication");
1744 send_packet(SSH1_CMSG_AUTH_TIS, PKT_END);
1745 crWaitUntil(ispkt);
1746 if (pktin.type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
1747 logevent("TIS authentication declined");
1748 if (flags & FLAG_INTERACTIVE)
1749 c_write_str("TIS authentication refused.\r\n");
1750 } else {
1751 int challengelen = ((pktin.body[0] << 24) |
1752 (pktin.body[1] << 16) |
1753 (pktin.body[2] << 8) |
1754 (pktin.body[3]));
1755 logevent("Received TIS challenge");
1756 if (challengelen > sizeof(prompt)-1)
1757 challengelen = sizeof(prompt)-1; /* prevent overrun */
1758 memcpy(prompt, pktin.body+4, challengelen);
1759 prompt[challengelen] = '\0';
1760 }
1761 }
1762 if (pktin.type == SSH1_SMSG_FAILURE &&
1763 cfg.try_tis_auth &&
1764 (supported_auths_mask & (1<<SSH1_AUTH_CCARD))) {
1765 pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE;
1766 logevent("Requested CryptoCard authentication");
1767 send_packet(SSH1_CMSG_AUTH_CCARD, PKT_END);
1768 crWaitUntil(ispkt);
1769 if (pktin.type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
1770 logevent("CryptoCard authentication declined");
1771 c_write_str("CryptoCard authentication refused.\r\n");
1772 } else {
1773 int challengelen = ((pktin.body[0] << 24) |
1774 (pktin.body[1] << 16) |
1775 (pktin.body[2] << 8) |
1776 (pktin.body[3]));
1777 logevent("Received CryptoCard challenge");
1778 if (challengelen > sizeof(prompt)-1)
1779 challengelen = sizeof(prompt)-1; /* prevent overrun */
1780 memcpy(prompt, pktin.body+4, challengelen);
1781 strncpy(prompt + challengelen, "\r\nResponse : ",
1782 sizeof(prompt)-challengelen);
1783 prompt[sizeof(prompt)-1] = '\0';
1784 }
1785 }
1786 if (pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
1787 sprintf(prompt, "%.90s@%.90s's password: ",
1788 username, savedhost);
1789 }
1790 if (pwpkt_type == SSH1_CMSG_AUTH_RSA) {
1791 char *comment = NULL;
1792 if (flags & FLAG_VERBOSE)
1793 c_write_str("Trying public key authentication.\r\n");
1794 if (!rsakey_encrypted(cfg.keyfile, &comment)) {
1795 if (flags & FLAG_VERBOSE)
1796 c_write_str("No passphrase required.\r\n");
1797 goto tryauth;
1798 }
1799 sprintf(prompt, "Passphrase for key \"%.100s\": ", comment);
1800 sfree(comment);
1801 }
1802
1803 if (ssh_get_line) {
1804 if (!ssh_get_line(prompt, password, sizeof(password), TRUE)) {
1805 /*
1806 * get_line failed to get a password (for example
1807 * because one was supplied on the command line
1808 * which has already failed to work). Terminate.
1809 */
1810 logevent("No more passwords to try");
1811 ssh_state = SSH_STATE_CLOSED;
1812 crReturn(1);
1813 }
1814 } else {
1815 c_write_str(prompt);
1816 pos = 0;
1817 ssh_send_ok = 1;
1818 while (pos >= 0) {
1819 crWaitUntil(!ispkt);
1820 while (inlen--) switch (c = *in++) {
1821 case 10: case 13:
1822 password[pos] = 0;
1823 pos = -1;
1824 break;
1825 case 8: case 127:
1826 if (pos > 0)
1827 pos--;
1828 break;
1829 case 21: case 27:
1830 pos = 0;
1831 break;
1832 case 3: case 4:
1833 random_save_seed();
1834 exit(0);
1835 break;
1836 default:
1837 if (((c >= ' ' && c <= '~') ||
1838 ((unsigned char)c >= 160)) && pos < sizeof(password))
1839 password[pos++] = c;
1840 break;
1841 }
1842 }
1843 c_write_str("\r\n");
1844 }
1845
1846 tryauth:
1847 if (pwpkt_type == SSH1_CMSG_AUTH_RSA) {
1848 /*
1849 * Try public key authentication with the specified
1850 * key file.
1851 */
1852 static struct RSAKey pubkey;
1853 static Bignum challenge, response;
1854 static int i;
1855 static unsigned char buffer[32];
1856
1857 tried_publickey = 1;
1858 i = loadrsakey(cfg.keyfile, &pubkey, password);
1859 if (i == 0) {
1860 c_write_str("Couldn't load public key from ");
1861 c_write_str(cfg.keyfile);
1862 c_write_str(".\r\n");
1863 continue; /* go and try password */
1864 }
1865 if (i == -1) {
1866 c_write_str("Wrong passphrase.\r\n");
1867 tried_publickey = 0;
1868 continue; /* try again */
1869 }
1870
1871 /*
1872 * Send a public key attempt.
1873 */
1874 send_packet(SSH1_CMSG_AUTH_RSA,
1875 PKT_BIGNUM, pubkey.modulus, PKT_END);
1876
1877 crWaitUntil(ispkt);
1878 if (pktin.type == SSH1_SMSG_FAILURE) {
1879 c_write_str("Server refused our public key.\r\n");
1880 continue; /* go and try password */
1881 }
1882 if (pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
1883 bombout(("Bizarre response to offer of public key"));
1884 crReturn(0);
1885 }
1886 ssh1_read_bignum(pktin.body, &challenge);
1887 response = rsadecrypt(challenge, &pubkey);
1888 freebn(pubkey.private_exponent); /* burn the evidence */
1889
1890 for (i = 0; i < 32; i++) {
1891 buffer[i] = bignum_byte(response, 31-i);
1892 }
1893
1894 MD5Init(&md5c);
1895 MD5Update(&md5c, buffer, 32);
1896 MD5Update(&md5c, session_id, 16);
1897 MD5Final(buffer, &md5c);
1898
1899 send_packet(SSH1_CMSG_AUTH_RSA_RESPONSE,
1900 PKT_DATA, buffer, 16, PKT_END);
1901
1902 crWaitUntil(ispkt);
1903 if (pktin.type == SSH1_SMSG_FAILURE) {
1904 if (flags & FLAG_VERBOSE)
1905 c_write_str("Failed to authenticate with our public key.\r\n");
1906 continue; /* go and try password */
1907 } else if (pktin.type != SSH1_SMSG_SUCCESS) {
1908 bombout(("Bizarre response to RSA authentication response"));
1909 crReturn(0);
1910 }
1911
1912 break; /* we're through! */
1913 } else {
1914 if (pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
1915 /*
1916 * Defence against traffic analysis: we send a
1917 * whole bunch of packets containing strings of
1918 * different lengths. One of these strings is the
1919 * password, in a SSH1_CMSG_AUTH_PASSWORD packet.
1920 * The others are all random data in
1921 * SSH1_MSG_IGNORE packets. This way a passive
1922 * listener can't tell which is the password, and
1923 * hence can't deduce the password length.
1924 *
1925 * Anybody with a password length greater than 16
1926 * bytes is going to have enough entropy in their
1927 * password that a listener won't find it _that_
1928 * much help to know how long it is. So what we'll
1929 * do is:
1930 *
1931 * - if password length < 16, we send 15 packets
1932 * containing string lengths 1 through 15
1933 *
1934 * - otherwise, we let N be the nearest multiple
1935 * of 8 below the password length, and send 8
1936 * packets containing string lengths N through
1937 * N+7. This won't obscure the order of
1938 * magnitude of the password length, but it will
1939 * introduce a bit of extra uncertainty.
1940 *
1941 * A few servers (the old 1.2.18 through 1.2.22)
1942 * can't deal with SSH1_MSG_IGNORE. For these
1943 * servers, we need an alternative defence. We make
1944 * use of the fact that the password is interpreted
1945 * as a C string: so we can append a NUL, then some
1946 * random data.
1947 */
1948 if (ssh_remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE) {
1949 char string[64];
1950 char *s;
1951 int len;
1952
1953 len = strlen(password);
1954 if (len < sizeof(string)) {
1955 s = string;
1956 strcpy(string, password);
1957 len++; /* cover the zero byte */
1958 while (len < sizeof(string)) {
1959 string[len++] = (char)random_byte();
1960 }
1961 } else {
1962 s = password;
1963 }
1964 send_packet(pwpkt_type, PKT_INT, len,
1965 PKT_DATA, s, len, PKT_END);
1966 } else {
1967 int bottom, top, pwlen, i;
1968 char *randomstr;
1969
1970 pwlen = strlen(password);
1971 if (pwlen < 16) {
1972 bottom = 0; /* zero length passwords are OK! :-) */
1973 top = 15;
1974 } else {
1975 bottom = pwlen &~ 7;
1976 top = bottom + 7;
1977 }
1978
1979 assert(pwlen >= bottom && pwlen <= top);
1980
1981 randomstr = smalloc(top+1);
1982
1983 for (i = bottom; i <= top; i++) {
1984 if (i == pwlen)
1985 defer_packet(pwpkt_type, PKT_STR, password, PKT_END);
1986 else {
1987 for (j = 0; j < i; j++) {
1988 do {
1989 randomstr[j] = random_byte();
1990 } while (randomstr[j] == '\0');
1991 }
1992 randomstr[i] = '\0';
1993 defer_packet(SSH1_MSG_IGNORE,
1994 PKT_STR, randomstr, PKT_END);
1995 }
1996 }
1997 ssh_pkt_defersend();
1998 }
1999 } else {
2000 send_packet(pwpkt_type, PKT_STR, password, PKT_END);
2001 }
2002 }
2003 logevent("Sent password");
2004 memset(password, 0, strlen(password));
2005 crWaitUntil(ispkt);
2006 if (pktin.type == SSH1_SMSG_FAILURE) {
2007 if (flags & FLAG_VERBOSE)
2008 c_write_str("Access denied\r\n");
2009 logevent("Authentication refused");
2010 } else if (pktin.type == SSH1_MSG_DISCONNECT) {
2011 logevent("Received disconnect request");
2012 ssh_state = SSH_STATE_CLOSED;
2013 crReturn(1);
2014 } else if (pktin.type != SSH1_SMSG_SUCCESS) {
2015 bombout(("Strange packet received, type %d", pktin.type));
2016 crReturn(0);
2017 }
2018 }
2019
2020 logevent("Authentication successful");
2021
2022 crFinish(1);
2023 }
2024
2025 void sshfwd_close(struct ssh_channel *c) {
2026 if (c && !c->closes) {
2027 if (ssh_version == 1) {
2028 send_packet(SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid, PKT_END);
2029 } else {
2030 ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE);
2031 ssh2_pkt_adduint32(c->remoteid);
2032 ssh2_pkt_send();
2033 }
2034 c->closes = 1;
2035 if (c->type == CHAN_X11) {
2036 c->u.x11.s = NULL;
2037 logevent("X11 connection terminated");
2038 }
2039 }
2040 }
2041
2042 void sshfwd_write(struct ssh_channel *c, char *buf, int len) {
2043 if (ssh_version == 1) {
2044 send_packet(SSH1_MSG_CHANNEL_DATA,
2045 PKT_INT, c->remoteid,
2046 PKT_INT, len,
2047 PKT_DATA, buf, len,
2048 PKT_END);
2049 } else {
2050 ssh2_add_channel_data(c, buf, len);
2051 ssh2_try_send(c);
2052 }
2053 }
2054
2055 static void ssh1_protocol(unsigned char *in, int inlen, int ispkt) {
2056 crBegin;
2057
2058 random_init();
2059
2060 while (!do_ssh1_login(in, inlen, ispkt)) {
2061 crReturnV;
2062 }
2063 if (ssh_state == SSH_STATE_CLOSED)
2064 crReturnV;
2065
2066 if (cfg.agentfwd && agent_exists()) {
2067 logevent("Requesting agent forwarding");
2068 send_packet(SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END);
2069 do { crReturnV; } while (!ispkt);
2070 if (pktin.type != SSH1_SMSG_SUCCESS && pktin.type != SSH1_SMSG_FAILURE) {
2071 bombout(("Protocol confusion"));
2072 crReturnV;
2073 } else if (pktin.type == SSH1_SMSG_FAILURE) {
2074 logevent("Agent forwarding refused");
2075 } else {
2076 logevent("Agent forwarding enabled");
2077 ssh_agentfwd_enabled = TRUE;
2078 }
2079 }
2080
2081 if (cfg.x11_forward) {
2082 char proto[20], data[64];
2083 logevent("Requesting X11 forwarding");
2084 x11_invent_auth(proto, sizeof(proto), data, sizeof(data));
2085 if (ssh1_local_protoflags & SSH1_PROTOFLAG_SCREEN_NUMBER) {
2086 send_packet(SSH1_CMSG_X11_REQUEST_FORWARDING,
2087 PKT_STR, proto, PKT_STR, data,
2088 PKT_INT, 0,
2089 PKT_END);
2090 } else {
2091 send_packet(SSH1_CMSG_X11_REQUEST_FORWARDING,
2092 PKT_STR, proto, PKT_STR, data,
2093 PKT_END);
2094 }
2095 do { crReturnV; } while (!ispkt);
2096 if (pktin.type != SSH1_SMSG_SUCCESS && pktin.type != SSH1_SMSG_FAILURE) {
2097 bombout(("Protocol confusion"));
2098 crReturnV;
2099 } else if (pktin.type == SSH1_SMSG_FAILURE) {
2100 logevent("X11 forwarding refused");
2101 } else {
2102 logevent("X11 forwarding enabled");
2103 ssh_X11_fwd_enabled = TRUE;
2104 }
2105 }
2106
2107 if (!cfg.nopty) {
2108 send_packet(SSH1_CMSG_REQUEST_PTY,
2109 PKT_STR, cfg.termtype,
2110 PKT_INT, rows, PKT_INT, cols,
2111 PKT_INT, 0, PKT_INT, 0,
2112 PKT_CHAR, 0,
2113 PKT_END);
2114 ssh_state = SSH_STATE_INTERMED;
2115 do { crReturnV; } while (!ispkt);
2116 if (pktin.type != SSH1_SMSG_SUCCESS && pktin.type != SSH1_SMSG_FAILURE) {
2117 bombout(("Protocol confusion"));
2118 crReturnV;
2119 } else if (pktin.type == SSH1_SMSG_FAILURE) {
2120 c_write_str("Server refused to allocate pty\r\n");
2121 ssh_editing = ssh_echoing = 1;
2122 }
2123 logevent("Allocated pty");
2124 } else {
2125 ssh_editing = ssh_echoing = 1;
2126 }
2127
2128 if (cfg.compression) {
2129 send_packet(SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END);
2130 do { crReturnV; } while (!ispkt);
2131 if (pktin.type != SSH1_SMSG_SUCCESS && pktin.type != SSH1_SMSG_FAILURE) {
2132 bombout(("Protocol confusion"));
2133 crReturnV;
2134 } else if (pktin.type == SSH1_SMSG_FAILURE) {
2135 c_write_str("Server refused to compress\r\n");
2136 }
2137 logevent("Started compression");
2138 ssh1_compressing = TRUE;
2139 zlib_compress_init();
2140 zlib_decompress_init();
2141 }
2142
2143 if (*cfg.remote_cmd_ptr)
2144 send_packet(SSH1_CMSG_EXEC_CMD, PKT_STR, cfg.remote_cmd_ptr, PKT_END);
2145 else
2146 send_packet(SSH1_CMSG_EXEC_SHELL, PKT_END);
2147 logevent("Started session");
2148
2149 ssh_state = SSH_STATE_SESSION;
2150 if (size_needed)
2151 ssh_size();
2152 if (eof_needed)
2153 ssh_special(TS_EOF);
2154
2155 ldisc_send(NULL, 0); /* cause ldisc to notice changes */
2156 ssh_send_ok = 1;
2157 ssh_channels = newtree234(ssh_channelcmp);
2158 while (1) {
2159 crReturnV;
2160 if (ispkt) {
2161 if (pktin.type == SSH1_SMSG_STDOUT_DATA ||
2162 pktin.type == SSH1_SMSG_STDERR_DATA) {
2163 long len = GET_32BIT(pktin.body);
2164 from_backend(pktin.type == SSH1_SMSG_STDERR_DATA,
2165 pktin.body+4, len);
2166 } else if (pktin.type == SSH1_MSG_DISCONNECT) {
2167 ssh_state = SSH_STATE_CLOSED;
2168 logevent("Received disconnect request");
2169 crReturnV;
2170 } else if (pktin.type == SSH1_SMSG_X11_OPEN) {
2171 /* Remote side is trying to open a channel to talk to our
2172 * X-Server. Give them back a local channel number. */
2173 unsigned i;
2174 struct ssh_channel *c, *d;
2175 enum234 e;
2176
2177 logevent("Received X11 connect request");
2178 /* Refuse if X11 forwarding is disabled. */
2179 if (!ssh_X11_fwd_enabled) {
2180 send_packet(SSH1_MSG_CHANNEL_OPEN_FAILURE,
2181 PKT_INT, GET_32BIT(pktin.body),
2182 PKT_END);
2183 logevent("Rejected X11 connect request");
2184 } else {
2185 c = smalloc(sizeof(struct ssh_channel));
2186
2187 if ( x11_init(&c->u.x11.s, cfg.x11_display, c) != NULL ) {
2188 logevent("opening X11 forward connection failed");
2189 sfree(c);
2190 send_packet(SSH1_MSG_CHANNEL_OPEN_FAILURE,
2191 PKT_INT, GET_32BIT(pktin.body),
2192 PKT_END);
2193 } else {
2194 logevent("opening X11 forward connection succeeded");
2195 for (i=1, d = first234(ssh_channels, &e); d; d = next234(&e)) {
2196 if (d->localid > i)
2197 break; /* found a free number */
2198 i = d->localid + 1;
2199 }
2200 c->remoteid = GET_32BIT(pktin.body);
2201 c->localid = i;
2202 c->closes = 0;
2203 c->type = CHAN_X11; /* identify channel type */
2204 add234(ssh_channels, c);
2205 send_packet(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
2206 PKT_INT, c->remoteid, PKT_INT, c->localid,
2207 PKT_END);
2208 logevent("Opened X11 forward channel");
2209 }
2210 }
2211 } else if (pktin.type == SSH1_SMSG_AGENT_OPEN) {
2212 /* Remote side is trying to open a channel to talk to our
2213 * agent. Give them back a local channel number. */
2214 unsigned i;
2215 struct ssh_channel *c;
2216 enum234 e;
2217
2218 /* Refuse if agent forwarding is disabled. */
2219 if (!ssh_agentfwd_enabled) {
2220 send_packet(SSH1_MSG_CHANNEL_OPEN_FAILURE,
2221 PKT_INT, GET_32BIT(pktin.body),
2222 PKT_END);
2223 } else {
2224 i = 1;
2225 for (c = first234(ssh_channels, &e); c; c = next234(&e)) {
2226 if (c->localid > i)
2227 break; /* found a free number */
2228 i = c->localid + 1;
2229 }
2230 c = smalloc(sizeof(struct ssh_channel));
2231 c->remoteid = GET_32BIT(pktin.body);
2232 c->localid = i;
2233 c->closes = 0;
2234 c->type = CHAN_AGENT; /* identify channel type */
2235 c->u.a.lensofar = 0;
2236 add234(ssh_channels, c);
2237 send_packet(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
2238 PKT_INT, c->remoteid, PKT_INT, c->localid,
2239 PKT_END);
2240 }
2241 } else if (pktin.type == SSH1_MSG_CHANNEL_CLOSE ||
2242 pktin.type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION) {
2243 /* Remote side closes a channel. */
2244 unsigned i = GET_32BIT(pktin.body);
2245 struct ssh_channel *c;
2246 c = find234(ssh_channels, &i, ssh_channelfind);
2247 if (c) {
2248 int closetype;
2249 closetype = (pktin.type == SSH1_MSG_CHANNEL_CLOSE ? 1 : 2);
2250 if (!(c->closes & closetype))
2251 send_packet(pktin.type, PKT_INT, c->remoteid, PKT_END);
2252 if ((c->closes == 0) && (c->type == CHAN_X11)) {
2253 logevent("X11 connection closed");
2254 assert(c->u.x11.s != NULL);
2255 x11_close(c->u.x11.s);
2256 c->u.x11.s = NULL;
2257 }
2258 c->closes |= closetype;
2259 if (c->closes == 3) {
2260 del234(ssh_channels, c);
2261 sfree(c);
2262 }
2263 }
2264 } else if (pktin.type == SSH1_MSG_CHANNEL_DATA) {
2265 /* Data sent down one of our channels. */
2266 int i = GET_32BIT(pktin.body);
2267 int len = GET_32BIT(pktin.body+4);
2268 unsigned char *p = pktin.body+8;
2269 struct ssh_channel *c;
2270 c = find234(ssh_channels, &i, ssh_channelfind);
2271 if (c) {
2272 switch(c->type) {
2273 case CHAN_X11:
2274 x11_send(c->u.x11.s, p, len);
2275 break;
2276 case CHAN_AGENT:
2277 /* Data for an agent message. Buffer it. */
2278 while (len > 0) {
2279 if (c->u.a.lensofar < 4) {
2280 int l = min(4 - c->u.a.lensofar, len);
2281 memcpy(c->u.a.msglen + c->u.a.lensofar, p, l);
2282 p += l; len -= l; c->u.a.lensofar += l;
2283 }
2284 if (c->u.a.lensofar == 4) {
2285 c->u.a.totallen = 4 + GET_32BIT(c->u.a.msglen);
2286 c->u.a.message = smalloc(c->u.a.totallen);
2287 memcpy(c->u.a.message, c->u.a.msglen, 4);
2288 }
2289 if (c->u.a.lensofar >= 4 && len > 0) {
2290 int l = min(c->u.a.totallen - c->u.a.lensofar, len);
2291 memcpy(c->u.a.message + c->u.a.lensofar, p, l);
2292 p += l; len -= l; c->u.a.lensofar += l;
2293 }
2294 if (c->u.a.lensofar == c->u.a.totallen) {
2295 void *reply, *sentreply;
2296 int replylen;
2297 agent_query(c->u.a.message, c->u.a.totallen,
2298 &reply, &replylen);
2299 if (reply)
2300 sentreply = reply;
2301 else {
2302 /* Fake SSH_AGENT_FAILURE. */
2303 sentreply = "\0\0\0\1\5";
2304 replylen = 5;
2305 }
2306 send_packet(SSH1_MSG_CHANNEL_DATA,
2307 PKT_INT, c->remoteid,
2308 PKT_INT, replylen,
2309 PKT_DATA, sentreply, replylen,
2310 PKT_END);
2311 if (reply)
2312 sfree(reply);
2313 sfree(c->u.a.message);
2314 c->u.a.lensofar = 0;
2315 }
2316 }
2317 break;
2318 }
2319 }
2320 } else if (pktin.type == SSH1_SMSG_SUCCESS) {
2321 /* may be from EXEC_SHELL on some servers */
2322 } else if (pktin.type == SSH1_SMSG_FAILURE) {
2323 /* may be from EXEC_SHELL on some servers
2324 * if no pty is available or in other odd cases. Ignore */
2325 } else if (pktin.type == SSH1_SMSG_EXIT_STATUS) {
2326 send_packet(SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
2327 } else {
2328 bombout(("Strange packet received: type %d", pktin.type));
2329 crReturnV;
2330 }
2331 } else {
2332 while (inlen > 0) {
2333 int len = min(inlen, 512);
2334 send_packet(SSH1_CMSG_STDIN_DATA,
2335 PKT_INT, len, PKT_DATA, in, len, PKT_END);
2336 in += len;
2337 inlen -= len;
2338 }
2339 }
2340 }
2341
2342 crFinishV;
2343 }
2344
2345 /*
2346 * Utility routine for decoding comma-separated strings in KEXINIT.
2347 */
2348 static int in_commasep_string(char *needle, char *haystack, int haylen) {
2349 int needlen = strlen(needle);
2350 while (1) {
2351 /*
2352 * Is it at the start of the string?
2353 */
2354 if (haylen >= needlen && /* haystack is long enough */
2355 !memcmp(needle, haystack, needlen) && /* initial match */
2356 (haylen == needlen || haystack[needlen] == ',')
2357 /* either , or EOS follows */
2358 )
2359 return 1;
2360 /*
2361 * If not, search for the next comma and resume after that.
2362 * If no comma found, terminate.
2363 */
2364 while (haylen > 0 && *haystack != ',')
2365 haylen--, haystack++;
2366 if (haylen == 0)
2367 return 0;
2368 haylen--, haystack++; /* skip over comma itself */
2369 }
2370 }
2371
2372 /*
2373 * SSH2 key creation method.
2374 */
2375 static void ssh2_mkkey(Bignum K, char *H, char *sessid, char chr, char *keyspace) {
2376 SHA_State s;
2377 /* First 20 bytes. */
2378 SHA_Init(&s);
2379 sha_mpint(&s, K);
2380 SHA_Bytes(&s, H, 20);
2381 SHA_Bytes(&s, &chr, 1);
2382 SHA_Bytes(&s, sessid, 20);
2383 SHA_Final(&s, keyspace);
2384 /* Next 20 bytes. */
2385 SHA_Init(&s);
2386 sha_mpint(&s, K);
2387 SHA_Bytes(&s, H, 20);
2388 SHA_Bytes(&s, keyspace, 20);
2389 SHA_Final(&s, keyspace+20);
2390 }
2391
2392 /*
2393 * Handle the SSH2 transport layer.
2394 */
2395 static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt)
2396 {
2397 static int i, j, len, nbits, pbits;
2398 static char *str;
2399 static Bignum p, g, e, f, K;
2400 static int kex_init_value, kex_reply_value;
2401 static const struct ssh_mac **maclist;
2402 static int nmacs;
2403 static const struct ssh2_cipher *cscipher_tobe = NULL;
2404 static const struct ssh2_cipher *sccipher_tobe = NULL;
2405 static const struct ssh_mac *csmac_tobe = NULL;
2406 static const struct ssh_mac *scmac_tobe = NULL;
2407 static const struct ssh_compress *cscomp_tobe = NULL;
2408 static const struct ssh_compress *sccomp_tobe = NULL;
2409 static char *hostkeydata, *sigdata, *keystr, *fingerprint;
2410 static int hostkeylen, siglen;
2411 static void *hkey; /* actual host key */
2412 static unsigned char exchange_hash[20];
2413 static unsigned char keyspace[40];
2414 static const struct ssh2_ciphers *preferred_cipher;
2415 static const struct ssh_compress *preferred_comp;
2416 static int first_kex;
2417
2418 crBegin;
2419 random_init();
2420 first_kex = 1;
2421
2422 /*
2423 * Set up the preferred cipher and compression.
2424 */
2425 if (cfg.cipher == CIPHER_BLOWFISH) {
2426 preferred_cipher = &ssh2_blowfish;
2427 } else if (cfg.cipher == CIPHER_DES) {
2428 logevent("Single DES not supported in SSH2; using 3DES");
2429 preferred_cipher = &ssh2_3des;
2430 } else if (cfg.cipher == CIPHER_3DES) {
2431 preferred_cipher = &ssh2_3des;
2432 } else if (cfg.cipher == CIPHER_AES) {
2433 preferred_cipher = &ssh2_aes;
2434 } else {
2435 /* Shouldn't happen, but we do want to initialise to _something_. */
2436 preferred_cipher = &ssh2_3des;
2437 }
2438 if (cfg.compression)
2439 preferred_comp = &ssh_zlib;
2440 else
2441 preferred_comp = &ssh_comp_none;
2442
2443 /*
2444 * Be prepared to work around the buggy MAC problem.
2445 */
2446 if (cfg.buggymac || (ssh_remote_bugs & BUG_SSH2_HMAC))
2447 maclist = buggymacs, nmacs = lenof(buggymacs);
2448 else
2449 maclist = macs, nmacs = lenof(macs);
2450
2451 begin_key_exchange:
2452 /*
2453 * Construct and send our key exchange packet.
2454 */
2455 ssh2_pkt_init(SSH2_MSG_KEXINIT);
2456 for (i = 0; i < 16; i++)
2457 ssh2_pkt_addbyte((unsigned char)random_byte());
2458 /* List key exchange algorithms. */
2459 ssh2_pkt_addstring_start();
2460 for (i = 0; i < lenof(kex_algs); i++) {
2461 ssh2_pkt_addstring_str(kex_algs[i]->name);
2462 if (i < lenof(kex_algs)-1)
2463 ssh2_pkt_addstring_str(",");
2464 }
2465 /* List server host key algorithms. */
2466 ssh2_pkt_addstring_start();
2467 for (i = 0; i < lenof(hostkey_algs); i++) {
2468 ssh2_pkt_addstring_str(hostkey_algs[i]->name);
2469 if (i < lenof(hostkey_algs)-1)
2470 ssh2_pkt_addstring_str(",");
2471 }
2472 /* List client->server encryption algorithms. */
2473 ssh2_pkt_addstring_start();
2474 for (i = 0; i < lenof(ciphers)+1; i++) {
2475 const struct ssh2_ciphers *c = i==0 ? preferred_cipher : ciphers[i-1];
2476 for (j = 0; j < c->nciphers; j++) {
2477 ssh2_pkt_addstring_str(c->list[j]->name);
2478 if (i < lenof(ciphers) || j < c->nciphers-1)
2479 ssh2_pkt_addstring_str(",");
2480 }
2481 }
2482 /* List server->client encryption algorithms. */
2483 ssh2_pkt_addstring_start();
2484 for (i = 0; i < lenof(ciphers)+1; i++) {
2485 const struct ssh2_ciphers *c = i==0 ? preferred_cipher : ciphers[i-1];
2486 for (j = 0; j < c->nciphers; j++) {
2487 ssh2_pkt_addstring_str(c->list[j]->name);
2488 if (i < lenof(ciphers) || j < c->nciphers-1)
2489 ssh2_pkt_addstring_str(",");
2490 }
2491 }
2492 /* List client->server MAC algorithms. */
2493 ssh2_pkt_addstring_start();
2494 for (i = 0; i < nmacs; i++) {
2495 ssh2_pkt_addstring_str(maclist[i]->name);
2496 if (i < nmacs-1)
2497 ssh2_pkt_addstring_str(",");
2498 }
2499 /* List server->client MAC algorithms. */
2500 ssh2_pkt_addstring_start();
2501 for (i = 0; i < nmacs; i++) {
2502 ssh2_pkt_addstring_str(maclist[i]->name);
2503 if (i < nmacs-1)
2504 ssh2_pkt_addstring_str(",");
2505 }
2506 /* List client->server compression algorithms. */
2507 ssh2_pkt_addstring_start();
2508 for (i = 0; i < lenof(compressions)+1; i++) {
2509 const struct ssh_compress *c = i==0 ? preferred_comp : compressions[i-1];
2510 ssh2_pkt_addstring_str(c->name);
2511 if (i < lenof(compressions))
2512 ssh2_pkt_addstring_str(",");
2513 }
2514 /* List server->client compression algorithms. */
2515 ssh2_pkt_addstring_start();
2516 for (i = 0; i < lenof(compressions)+1; i++) {
2517 const struct ssh_compress *c = i==0 ? preferred_comp : compressions[i-1];
2518 ssh2_pkt_addstring_str(c->name);
2519 if (i < lenof(compressions))
2520 ssh2_pkt_addstring_str(",");
2521 }
2522 /* List client->server languages. Empty list. */
2523 ssh2_pkt_addstring_start();
2524 /* List server->client languages. Empty list. */
2525 ssh2_pkt_addstring_start();
2526 /* First KEX packet does _not_ follow, because we're not that brave. */
2527 ssh2_pkt_addbool(FALSE);
2528 /* Reserved. */
2529 ssh2_pkt_adduint32(0);
2530
2531 exhash = exhashbase;
2532 sha_string(&exhash, pktout.data+5, pktout.length-5);
2533
2534 ssh2_pkt_send();
2535
2536 if (!ispkt) crWaitUntil(ispkt);
2537 sha_string(&exhash, pktin.data+5, pktin.length-5);
2538
2539 /*
2540 * Now examine the other side's KEXINIT to see what we're up
2541 * to.
2542 */
2543 if (pktin.type != SSH2_MSG_KEXINIT) {
2544 bombout(("expected key exchange packet from server"));
2545 crReturn(0);
2546 }
2547 kex = NULL; hostkey = NULL; cscipher_tobe = NULL; sccipher_tobe = NULL;
2548 csmac_tobe = NULL; scmac_tobe = NULL; cscomp_tobe = NULL; sccomp_tobe = NULL;
2549 pktin.savedpos += 16; /* skip garbage cookie */
2550 ssh2_pkt_getstring(&str, &len); /* key exchange algorithms */
2551 for (i = 0; i < lenof(kex_algs); i++) {
2552 if (in_commasep_string(kex_algs[i]->name, str, len)) {
2553 kex = kex_algs[i];
2554 break;
2555 }
2556 }
2557 ssh2_pkt_getstring(&str, &len); /* host key algorithms */
2558 for (i = 0; i < lenof(hostkey_algs); i++) {
2559 if (in_commasep_string(hostkey_algs[i]->name, str, len)) {
2560 hostkey = hostkey_algs[i];
2561 break;
2562 }
2563 }
2564 ssh2_pkt_getstring(&str, &len); /* client->server cipher */
2565 for (i = 0; i < lenof(ciphers)+1; i++) {
2566 const struct ssh2_ciphers *c = i==0 ? preferred_cipher : ciphers[i-1];
2567 for (j = 0; j < c->nciphers; j++) {
2568 if (in_commasep_string(c->list[j]->name, str, len)) {
2569 cscipher_tobe = c->list[j];
2570 break;
2571 }
2572 }
2573 if (cscipher_tobe)
2574 break;
2575 }
2576 ssh2_pkt_getstring(&str, &len); /* server->client cipher */
2577 for (i = 0; i < lenof(ciphers)+1; i++) {
2578 const struct ssh2_ciphers *c = i==0 ? preferred_cipher : ciphers[i-1];
2579 for (j = 0; j < c->nciphers; j++) {
2580 if (in_commasep_string(c->list[j]->name, str, len)) {
2581 sccipher_tobe = c->list[j];
2582 break;
2583 }
2584 }
2585 if (sccipher_tobe)
2586 break;
2587 }
2588 ssh2_pkt_getstring(&str, &len); /* client->server mac */
2589 for (i = 0; i < nmacs; i++) {
2590 if (in_commasep_string(maclist[i]->name, str, len)) {
2591 csmac_tobe = maclist[i];
2592 break;
2593 }
2594 }
2595 ssh2_pkt_getstring(&str, &len); /* server->client mac */
2596 for (i = 0; i < nmacs; i++) {
2597 if (in_commasep_string(maclist[i]->name, str, len)) {
2598 scmac_tobe = maclist[i];
2599 break;
2600 }
2601 }
2602 ssh2_pkt_getstring(&str, &len); /* client->server compression */
2603 for (i = 0; i < lenof(compressions)+1; i++) {
2604 const struct ssh_compress *c = i==0 ? preferred_comp : compressions[i-1];
2605 if (in_commasep_string(c->name, str, len)) {
2606 cscomp_tobe = c;
2607 break;
2608 }
2609 }
2610 ssh2_pkt_getstring(&str, &len); /* server->client compression */
2611 for (i = 0; i < lenof(compressions)+1; i++) {
2612 const struct ssh_compress *c = i==0 ? preferred_comp : compressions[i-1];
2613 if (in_commasep_string(c->name, str, len)) {
2614 sccomp_tobe = c;
2615 break;
2616 }
2617 }
2618
2619 /*
2620 * Work out the number of bits of key we will need from the key
2621 * exchange. We start with the maximum key length of either
2622 * cipher...
2623 */
2624 {
2625 int csbits, scbits;
2626
2627 csbits = cscipher_tobe->keylen;
2628 scbits = sccipher_tobe->keylen;
2629 nbits = (csbits > scbits ? csbits : scbits);
2630 }
2631 /* The keys only have 160-bit entropy, since they're based on
2632 * a SHA-1 hash. So cap the key size at 160 bits. */
2633 if (nbits > 160) nbits = 160;
2634
2635 /*
2636 * If we're doing Diffie-Hellman group exchange, start by
2637 * requesting a group.
2638 */
2639 if (kex == &ssh_diffiehellman_gex) {
2640 logevent("Doing Diffie-Hellman group exchange");
2641 /*
2642 * Work out how big a DH group we will need to allow that
2643 * much data.
2644 */
2645 pbits = 512 << ((nbits-1) / 64);
2646 ssh2_pkt_init(SSH2_MSG_KEX_DH_GEX_REQUEST);
2647 ssh2_pkt_adduint32(pbits);
2648 ssh2_pkt_send();
2649
2650 crWaitUntil(ispkt);
2651 if (pktin.type != SSH2_MSG_KEX_DH_GEX_GROUP) {
2652 bombout(("expected key exchange group packet from server"));
2653 crReturn(0);
2654 }
2655 p = ssh2_pkt_getmp();
2656 g = ssh2_pkt_getmp();
2657 dh_setup_group(p, g);
2658 kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT;
2659 kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY;
2660 } else {
2661 dh_setup_group1();
2662 kex_init_value = SSH2_MSG_KEXDH_INIT;
2663 kex_reply_value = SSH2_MSG_KEXDH_REPLY;
2664 }
2665
2666 logevent("Doing Diffie-Hellman key exchange");
2667 /*
2668 * Now generate and send e for Diffie-Hellman.
2669 */
2670 e = dh_create_e(nbits*2);
2671 ssh2_pkt_init(kex_init_value);
2672 ssh2_pkt_addmp(e);
2673 ssh2_pkt_send();
2674
2675 crWaitUntil(ispkt);
2676 if (pktin.type != kex_reply_value) {
2677 bombout(("expected key exchange reply packet from server"));
2678 crReturn(0);
2679 }
2680 ssh2_pkt_getstring(&hostkeydata, &hostkeylen);
2681 f = ssh2_pkt_getmp();
2682 ssh2_pkt_getstring(&sigdata, &siglen);
2683
2684 K = dh_find_K(f);
2685
2686 sha_string(&exhash, hostkeydata, hostkeylen);
2687 if (kex == &ssh_diffiehellman_gex) {
2688 sha_uint32(&exhash, pbits);
2689 sha_mpint(&exhash, p);
2690 sha_mpint(&exhash, g);
2691 }
2692 sha_mpint(&exhash, e);
2693 sha_mpint(&exhash, f);
2694 sha_mpint(&exhash, K);
2695 SHA_Final(&exhash, exchange_hash);
2696
2697 dh_cleanup();
2698
2699 #if 0
2700 debug(("Exchange hash is:\r\n"));
2701 for (i = 0; i < 20; i++)
2702 debug((" %02x", exchange_hash[i]));
2703 debug(("\r\n"));
2704 #endif
2705
2706 hkey = hostkey->newkey(hostkeydata, hostkeylen);
2707 if (!hostkey->verifysig(hkey, sigdata, siglen, exchange_hash, 20)) {
2708 bombout(("Server failed host key check"));
2709 crReturn(0);
2710 }
2711
2712 /*
2713 * Expect SSH2_MSG_NEWKEYS from server.
2714 */
2715 crWaitUntil(ispkt);
2716 if (pktin.type != SSH2_MSG_NEWKEYS) {
2717 bombout(("expected new-keys packet from server"));
2718 crReturn(0);
2719 }
2720
2721 /*
2722 * Authenticate remote host: verify host key. (We've already
2723 * checked the signature of the exchange hash.)
2724 */
2725 keystr = hostkey->fmtkey(hkey);
2726 fingerprint = hostkey->fingerprint(hkey);
2727 verify_ssh_host_key(savedhost, savedport, hostkey->keytype,
2728 keystr, fingerprint);
2729 if (first_kex) { /* don't bother logging this in rekeys */
2730 logevent("Host key fingerprint is:");
2731 logevent(fingerprint);
2732 }
2733 sfree(fingerprint);
2734 sfree(keystr);
2735 hostkey->freekey(hkey);
2736
2737 /*
2738 * Send SSH2_MSG_NEWKEYS.
2739 */
2740 ssh2_pkt_init(SSH2_MSG_NEWKEYS);
2741 ssh2_pkt_send();
2742
2743 /*
2744 * Create and initialise session keys.
2745 */
2746 cscipher = cscipher_tobe;
2747 sccipher = sccipher_tobe;
2748 csmac = csmac_tobe;
2749 scmac = scmac_tobe;
2750 cscomp = cscomp_tobe;
2751 sccomp = sccomp_tobe;
2752 cscomp->compress_init();
2753 sccomp->decompress_init();
2754 /*
2755 * Set IVs after keys. Here we use the exchange hash from the
2756 * _first_ key exchange.
2757 */
2758 if (first_kex)
2759 memcpy(ssh2_session_id, exchange_hash, sizeof(exchange_hash));
2760 ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'C', keyspace);
2761 cscipher->setcskey(keyspace);
2762 ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'D', keyspace);
2763 sccipher->setsckey(keyspace);
2764 ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'A', keyspace);
2765 cscipher->setcsiv(keyspace);
2766 ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'B', keyspace);
2767 sccipher->setsciv(keyspace);
2768 ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'E', keyspace);
2769 csmac->setcskey(keyspace);
2770 ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'F', keyspace);
2771 scmac->setsckey(keyspace);
2772
2773 /*
2774 * If this is the first key exchange phase, we must pass the
2775 * SSH2_MSG_NEWKEYS packet to the next layer, not because it
2776 * wants to see it but because it will need time to initialise
2777 * itself before it sees an actual packet. In subsequent key
2778 * exchange phases, we don't pass SSH2_MSG_NEWKEYS on, because
2779 * it would only confuse the layer above.
2780 */
2781 if (!first_kex) {
2782 crReturn(0);
2783 }
2784 first_kex = 0;
2785
2786 /*
2787 * Now we're encrypting. Begin returning 1 to the protocol main
2788 * function so that other things can run on top of the
2789 * transport. If we ever see a KEXINIT, we must go back to the
2790 * start.
2791 */
2792 while (!(ispkt && pktin.type == SSH2_MSG_KEXINIT)) {
2793 crReturn(1);
2794 }
2795 logevent("Server initiated key re-exchange");
2796 goto begin_key_exchange;
2797
2798 crFinish(1);
2799 }
2800
2801 /*
2802 * Add data to an SSH2 channel output buffer.
2803 */
2804 static void ssh2_add_channel_data(struct ssh_channel *c, char *buf, int len) {
2805 if (c->v2.outbufsize <
2806 c->v2.outbuflen + len) {
2807 c->v2.outbufsize =
2808 c->v2.outbuflen + len + 1024;
2809 c->v2.outbuffer = srealloc(c->v2.outbuffer,
2810 c->v2.outbufsize);
2811 }
2812 memcpy(c->v2.outbuffer + c->v2.outbuflen,
2813 buf, len);
2814 c->v2.outbuflen += len;
2815 }
2816
2817 /*
2818 * Attempt to send data on an SSH2 channel.
2819 */
2820 static void ssh2_try_send(struct ssh_channel *c) {
2821 while (c->v2.remwindow > 0 &&
2822 c->v2.outbuflen > 0) {
2823 unsigned len = c->v2.remwindow;
2824 if (len > c->v2.outbuflen)
2825 len = c->v2.outbuflen;
2826 if (len > c->v2.remmaxpkt)
2827 len = c->v2.remmaxpkt;
2828 ssh2_pkt_init(SSH2_MSG_CHANNEL_DATA);
2829 ssh2_pkt_adduint32(c->remoteid);
2830 ssh2_pkt_addstring_start();
2831 ssh2_pkt_addstring_data(c->v2.outbuffer, len);
2832 ssh2_pkt_send();
2833 c->v2.outbuflen -= len;
2834 memmove(c->v2.outbuffer, c->v2.outbuffer+len,
2835 c->v2.outbuflen);
2836 c->v2.remwindow -= len;
2837 }
2838 }
2839
2840 /*
2841 * Handle the SSH2 userauth and connection layers.
2842 */
2843 static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt)
2844 {
2845 static unsigned long remote_winsize;
2846 static unsigned long remote_maxpkt;
2847 static enum {
2848 AUTH_INVALID, AUTH_PUBLICKEY_AGENT, AUTH_PUBLICKEY_FILE, AUTH_PASSWORD
2849 } method;
2850 static enum {
2851 AUTH_TYPE_NONE,
2852 AUTH_TYPE_PUBLICKEY,
2853 AUTH_TYPE_PUBLICKEY_OFFER_LOUD,
2854 AUTH_TYPE_PUBLICKEY_OFFER_QUIET,
2855 AUTH_TYPE_PASSWORD
2856 } type;
2857 static int gotit, need_pw, can_pubkey, can_passwd;
2858 static int tried_pubkey_config, tried_agent;
2859 static int we_are_in;
2860 static char username[100];
2861 static char pwprompt[200];
2862 static char password[100];
2863
2864 crBegin;
2865
2866 /*
2867 * Request userauth protocol, and await a response to it.
2868 */
2869 ssh2_pkt_init(SSH2_MSG_SERVICE_REQUEST);
2870 ssh2_pkt_addstring("ssh-userauth");
2871 ssh2_pkt_send();
2872 crWaitUntilV(ispkt);
2873 if (pktin.type != SSH2_MSG_SERVICE_ACCEPT) {
2874 bombout(("Server refused user authentication protocol"));
2875 crReturnV;
2876 }
2877
2878 /*
2879 * We repeat this whole loop, including the username prompt,
2880 * until we manage a successful authentication. If the user
2881 * types the wrong _password_, they are sent back to the
2882 * beginning to try another username. (If they specify a
2883 * username in the config, they are never asked, even if they
2884 * do give a wrong password.)
2885 *
2886 * I think this best serves the needs of
2887 *
2888 * - the people who have no configuration, no keys, and just
2889 * want to try repeated (username,password) pairs until they
2890 * type both correctly
2891 *
2892 * - people who have keys and configuration but occasionally
2893 * need to fall back to passwords
2894 *
2895 * - people with a key held in Pageant, who might not have
2896 * logged in to a particular machine before; so they want to
2897 * type a username, and then _either_ their key will be
2898 * accepted, _or_ they will type a password. If they mistype
2899 * the username they will want to be able to get back and
2900 * retype it!
2901 */
2902 do {
2903 static int pos;
2904 static char c;
2905
2906 /*
2907 * Get a username.
2908 */
2909 pos = 0;
2910 if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
2911 if (ssh_get_line) {
2912 if (!ssh_get_line("login as: ",
2913 username, sizeof(username), FALSE)) {
2914 /*
2915 * get_line failed to get a username.
2916 * Terminate.
2917 */
2918 logevent("No username provided. Abandoning session.");
2919 ssh_state = SSH_STATE_CLOSED;
2920 crReturnV;
2921 }
2922 } else {
2923 c_write_str("login as: ");
2924 ssh_send_ok = 1;
2925 while (pos >= 0) {
2926 crWaitUntilV(!ispkt);
2927 while (inlen--) switch (c = *in++) {
2928 case 10: case 13:
2929 username[pos] = 0;
2930 pos = -1;
2931 break;
2932 case 8: case 127:
2933 if (pos > 0) {
2934 c_write_str("\b \b");
2935 pos--;
2936 }
2937 break;
2938 case 21: case 27:
2939 while (pos > 0) {
2940 c_write_str("\b \b");
2941 pos--;
2942 }
2943 break;
2944 case 3: case 4:
2945 random_save_seed();
2946 exit(0);
2947 break;
2948 default:
2949 if (((c >= ' ' && c <= '~') ||
2950 ((unsigned char)c >= 160)) && pos < 40) {
2951 username[pos++] = c;
2952 c_write(&c, 1);
2953 }
2954 break;
2955 }
2956 }
2957 }
2958 c_write_str("\r\n");
2959 username[strcspn(username, "\n\r")] = '\0';
2960 } else {
2961 char stuff[200];
2962 strncpy(username, cfg.username, 99);
2963 username[99] = '\0';
2964 if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
2965 sprintf(stuff, "Using username \"%s\".\r\n", username);
2966 c_write_str(stuff);
2967 }
2968 }
2969
2970 /*
2971 * Send an authentication request using method "none": (a)
2972 * just in case it succeeds, and (b) so that we know what
2973 * authentication methods we can usefully try next.
2974 */
2975 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
2976 ssh2_pkt_addstring(username);
2977 ssh2_pkt_addstring("ssh-connection"); /* service requested */
2978 ssh2_pkt_addstring("none"); /* method */
2979 ssh2_pkt_send();
2980 type = AUTH_TYPE_NONE;
2981 gotit = FALSE;
2982 we_are_in = FALSE;
2983
2984 tried_pubkey_config = FALSE;
2985 tried_agent = FALSE;
2986
2987 while (1) {
2988 /*
2989 * Wait for the result of the last authentication request.
2990 */
2991 if (!gotit)
2992 crWaitUntilV(ispkt);
2993 while (pktin.type == SSH2_MSG_USERAUTH_BANNER) {
2994 char *banner;
2995 int size;
2996 /*
2997 * Don't show the banner if we're operating in
2998 * non-verbose non-interactive mode. (It's probably
2999 * a script, which means nobody will read the
3000 * banner _anyway_, and moreover the printing of
3001 * the banner will screw up processing on the
3002 * output of (say) plink.)
3003 */
3004 if (flags & (FLAG_VERBOSE | FLAG_INTERACTIVE)) {
3005 ssh2_pkt_getstring(&banner, &size);
3006 if (banner)
3007 c_write_untrusted(banner, size);
3008 }
3009 crWaitUntilV(ispkt);
3010 }
3011 if (pktin.type == SSH2_MSG_USERAUTH_SUCCESS) {
3012 logevent("Access granted");
3013 we_are_in = TRUE;
3014 break;
3015 }
3016
3017 if (pktin.type != SSH2_MSG_USERAUTH_FAILURE) {
3018 bombout(("Strange packet received during authentication: type %d",
3019 pktin.type));
3020 }
3021
3022 gotit = FALSE;
3023
3024 /*
3025 * OK, we're now sitting on a USERAUTH_FAILURE message, so
3026 * we can look at the string in it and know what we can
3027 * helpfully try next.
3028 */
3029 {
3030 char *methods;
3031 int methlen;
3032 ssh2_pkt_getstring(&methods, &methlen);
3033 if (!ssh2_pkt_getbool()) {
3034 /*
3035 * We have received an unequivocal Access
3036 * Denied. This can translate to a variety of
3037 * messages:
3038 *
3039 * - if we'd just tried "none" authentication,
3040 * it's not worth printing anything at all
3041 *
3042 * - if we'd just tried a public key _offer_,
3043 * the message should be "Server refused our
3044 * key" (or no message at all if the key
3045 * came from Pageant)
3046 *
3047 * - if we'd just tried anything else, the
3048 * message really should be "Access denied".
3049 *
3050 * Additionally, if we'd just tried password
3051 * authentication, we should break out of this
3052 * whole loop so as to go back to the username
3053 * prompt.
3054 */
3055 if (type == AUTH_TYPE_NONE) {
3056 /* do nothing */
3057 } else if (type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD ||
3058 type == AUTH_TYPE_PUBLICKEY_OFFER_QUIET) {
3059 if (type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD)
3060 c_write_str("Server refused our key\r\n");
3061 logevent("Server refused public key");
3062 } else {
3063 c_write_str("Access denied\r\n");
3064 logevent("Access denied");
3065 if (type == AUTH_TYPE_PASSWORD) {
3066 we_are_in = FALSE;
3067 break;
3068 }
3069 }
3070 } else {
3071 c_write_str("Further authentication required\r\n");
3072 logevent("Further authentication required");
3073 }
3074
3075 can_pubkey = in_commasep_string("publickey", methods, methlen);
3076 can_passwd = in_commasep_string("password", methods, methlen);
3077 }
3078
3079 method = 0;
3080
3081 if (!method && can_pubkey && agent_exists && !tried_agent) {
3082 /*
3083 * Attempt public-key authentication using Pageant.
3084 */
3085 static unsigned char request[5], *response, *p;
3086 static int responselen;
3087 static int i, nkeys;
3088 static int authed = FALSE;
3089 void *r;
3090
3091 tried_agent = TRUE;
3092
3093 logevent("Pageant is running. Requesting keys.");
3094
3095 /* Request the keys held by the agent. */
3096 PUT_32BIT(request, 1);
3097 request[4] = SSH2_AGENTC_REQUEST_IDENTITIES;
3098 agent_query(request, 5, &r, &responselen);
3099 response = (unsigned char *)r;
3100 if (response && responselen >= 5 &&
3101 response[4] == SSH2_AGENT_IDENTITIES_ANSWER) {
3102 p = response + 5;
3103 nkeys = GET_32BIT(p); p += 4;
3104 { char buf[64]; sprintf(buf, "Pageant has %d SSH2 keys", nkeys);
3105 logevent(buf); }
3106 for (i = 0; i < nkeys; i++) {
3107 static char *pkblob, *alg, *commentp;
3108 static int pklen, alglen, commentlen;
3109 static int siglen, retlen, len;
3110 static char *q, *agentreq, *ret;
3111
3112 { char buf[64]; sprintf(buf, "Trying Pageant key #%d", i);
3113 logevent(buf); }
3114 pklen = GET_32BIT(p); p += 4;
3115 pkblob = p; p += pklen;
3116 alglen = GET_32BIT(pkblob);
3117 alg = pkblob + 4;
3118 commentlen = GET_32BIT(p); p += 4;
3119 commentp = p; p += commentlen;
3120 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
3121 ssh2_pkt_addstring(username);
3122 ssh2_pkt_addstring("ssh-connection");/* service requested */
3123 ssh2_pkt_addstring("publickey");/* method */
3124 ssh2_pkt_addbool(FALSE); /* no signature included */
3125 ssh2_pkt_addstring_start();
3126 ssh2_pkt_addstring_data(alg, alglen);
3127 ssh2_pkt_addstring_start();
3128 ssh2_pkt_addstring_data(pkblob, pklen);
3129 ssh2_pkt_send();
3130
3131 crWaitUntilV(ispkt);
3132 if (pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
3133 logevent("Key refused");
3134 continue;
3135 }
3136
3137 if (flags & FLAG_VERBOSE) {
3138 c_write_str("Authenticating with public key \"");
3139 c_write(commentp, commentlen);
3140 c_write_str("\" from agent\r\n");
3141 }
3142
3143 /*
3144 * Server is willing to accept the key.
3145 * Construct a SIGN_REQUEST.
3146 */
3147 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
3148 ssh2_pkt_addstring(username);
3149 ssh2_pkt_addstring("ssh-connection"); /* service requested */
3150 ssh2_pkt_addstring("publickey"); /* method */
3151 ssh2_pkt_addbool(TRUE);
3152 ssh2_pkt_addstring_start();
3153 ssh2_pkt_addstring_data(alg, alglen);
3154 ssh2_pkt_addstring_start();
3155 ssh2_pkt_addstring_data(pkblob, pklen);
3156
3157 siglen = pktout.length - 5 + 4 + 20;
3158 len = 1; /* message type */
3159 len += 4 + pklen; /* key blob */
3160 len += 4 + siglen; /* data to sign */
3161 len += 4; /* flags */
3162 agentreq = smalloc(4 + len);
3163 PUT_32BIT(agentreq, len);
3164 q = agentreq + 4;
3165 *q++ = SSH2_AGENTC_SIGN_REQUEST;
3166 PUT_32BIT(q, pklen); q += 4;
3167 memcpy(q, pkblob, pklen); q += pklen;
3168 PUT_32BIT(q, siglen); q += 4;
3169 /* Now the data to be signed... */
3170 PUT_32BIT(q, 20); q += 4;
3171 memcpy(q, ssh2_session_id, 20); q += 20;
3172 memcpy(q, pktout.data+5, pktout.length-5);
3173 q += pktout.length-5;
3174 /* And finally the (zero) flags word. */
3175 PUT_32BIT(q, 0);
3176 agent_query(agentreq, len+4, &ret, &retlen);
3177 sfree(agentreq);
3178 if (ret) {
3179 if (ret[4] == SSH2_AGENT_SIGN_RESPONSE) {
3180 logevent("Sending Pageant's response");
3181 ssh2_pkt_addstring_start();
3182 ssh2_pkt_addstring_data(ret+9, GET_32BIT(ret+5));
3183 ssh2_pkt_send();
3184 authed = TRUE;
3185 break;
3186 } else {
3187 logevent("Pageant failed to answer challenge");
3188 sfree(ret);
3189 }
3190 }
3191 }
3192 if (authed)
3193 continue;
3194 }
3195 }
3196
3197 if (!method && can_pubkey && *cfg.keyfile && !tried_pubkey_config) {
3198 unsigned char *pub_blob;
3199 char *algorithm, *comment;
3200 int pub_blob_len;
3201
3202 tried_pubkey_config = TRUE;
3203
3204 /*
3205 * Try the public key supplied in the configuration.
3206 *
3207 * First, offer the public blob to see if the server is
3208 * willing to accept it.
3209 */
3210 pub_blob = ssh2_userkey_loadpub(cfg.keyfile, &algorithm,
3211 &pub_blob_len);
3212 if (pub_blob) {
3213 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
3214 ssh2_pkt_addstring(username);
3215 ssh2_pkt_addstring("ssh-connection"); /* service requested */
3216 ssh2_pkt_addstring("publickey");/* method */
3217 ssh2_pkt_addbool(FALSE); /* no signature included */
3218 ssh2_pkt_addstring(algorithm);
3219 ssh2_pkt_addstring_start();
3220 ssh2_pkt_addstring_data(pub_blob, pub_blob_len);
3221 ssh2_pkt_send();
3222 logevent("Offered public key"); /* FIXME */
3223
3224 crWaitUntilV(ispkt);
3225 if (pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
3226 gotit = TRUE;
3227 type = AUTH_TYPE_PUBLICKEY_OFFER_LOUD;
3228 continue; /* key refused; give up on it */
3229 }
3230
3231 logevent("Offer of public key accepted");
3232 /*
3233 * Actually attempt a serious authentication using
3234 * the key.
3235 */
3236 if (ssh2_userkey_encrypted(cfg.keyfile, &comment)) {
3237 sprintf(pwprompt, "Passphrase for key \"%.100s\": ", comment);
3238 need_pw = TRUE;
3239 } else {
3240 need_pw = FALSE;
3241 }
3242 c_write_str("Authenticating with public key \"");
3243 c_write_str(comment);
3244 c_write_str("\"\r\n");
3245 method = AUTH_PUBLICKEY_FILE;
3246 }
3247 }
3248
3249 if (!method && can_passwd) {
3250 method = AUTH_PASSWORD;
3251 sprintf(pwprompt, "%.90s@%.90s's password: ", username, savedhost);
3252 need_pw = TRUE;
3253 }
3254
3255 if (need_pw) {
3256 if (ssh_get_line) {
3257 if (!ssh_get_line(pwprompt, password,
3258 sizeof(password), TRUE)) {
3259 /*
3260 * get_line failed to get a password (for
3261 * example because one was supplied on the
3262 * command line which has already failed to
3263 * work). Terminate.
3264 */
3265 logevent("No more passwords to try");
3266 ssh_state = SSH_STATE_CLOSED;
3267 crReturnV;
3268 }
3269 } else {
3270 static int pos = 0;
3271 static char c;
3272
3273 c_write_str(pwprompt);
3274 ssh_send_ok = 1;
3275
3276 pos = 0;
3277 while (pos >= 0) {
3278 crWaitUntilV(!ispkt);
3279 while (inlen--) switch (c = *in++) {
3280 case 10: case 13:
3281 password[pos] = 0;
3282 pos = -1;
3283 break;
3284 case 8: case 127:
3285 if (pos > 0)
3286 pos--;
3287 break;
3288 case 21: case 27:
3289 pos = 0;
3290 break;
3291 case 3: case 4:
3292 random_save_seed();
3293 exit(0);
3294 break;
3295 default:
3296 if (((c >= ' ' && c <= '~') ||
3297 ((unsigned char)c >= 160)) && pos < 40)
3298 password[pos++] = c;
3299 break;
3300 }
3301 }
3302 c_write_str("\r\n");
3303 }
3304 }
3305
3306 if (method == AUTH_PUBLICKEY_FILE) {
3307 /*
3308 * We have our passphrase. Now try the actual authentication.
3309 */
3310 struct ssh2_userkey *key;
3311
3312 key = ssh2_load_userkey(cfg.keyfile, password);
3313 if (key == SSH2_WRONG_PASSPHRASE || key == NULL) {
3314 if (key == SSH2_WRONG_PASSPHRASE) {
3315 c_write_str("Wrong passphrase\r\n");
3316 tried_pubkey_config = FALSE;
3317 } else {
3318 c_write_str("Unable to load private key\r\n");
3319 tried_pubkey_config = TRUE;
3320 }
3321 /* Send a spurious AUTH_NONE to return to the top. */
3322 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
3323 ssh2_pkt_addstring(username);
3324 ssh2_pkt_addstring("ssh-connection"); /* service requested */
3325 ssh2_pkt_addstring("none"); /* method */
3326 ssh2_pkt_send();
3327 type = AUTH_TYPE_NONE;
3328 } else {
3329 unsigned char *blob, *sigdata;
3330 int blob_len, sigdata_len;
3331
3332 /*
3333 * We have loaded the private key and the server
3334 * has announced that it's willing to accept it.
3335 * Hallelujah. Generate a signature and send it.
3336 */
3337 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
3338 ssh2_pkt_addstring(username);
3339 ssh2_pkt_addstring("ssh-connection"); /* service requested */
3340 ssh2_pkt_addstring("publickey"); /* method */
3341 ssh2_pkt_addbool(TRUE);
3342 ssh2_pkt_addstring(key->alg->name);
3343 blob = key->alg->public_blob(key->data, &blob_len);
3344 ssh2_pkt_addstring_start();
3345 ssh2_pkt_addstring_data(blob, blob_len);
3346 sfree(blob);
3347
3348 /*
3349 * The data to be signed is:
3350 *
3351 * string session-id
3352 *
3353 * followed by everything so far placed in the
3354 * outgoing packet.
3355 */
3356 sigdata_len = pktout.length - 5 + 4 + 20;
3357 sigdata = smalloc(sigdata_len);
3358 PUT_32BIT(sigdata, 20);
3359 memcpy(sigdata+4, ssh2_session_id, 20);
3360 memcpy(sigdata+24, pktout.data+5, pktout.length-5);
3361 blob = key->alg->sign(key->data, sigdata, sigdata_len, &blob_len);
3362 ssh2_pkt_addstring_start();
3363 ssh2_pkt_addstring_data(blob, blob_len);
3364 sfree(blob);
3365 sfree(sigdata);
3366
3367 ssh2_pkt_send();
3368 type = AUTH_TYPE_PUBLICKEY;
3369 }
3370 } else if (method == AUTH_PASSWORD) {
3371 /*
3372 * We send the password packet lumped tightly together with
3373 * an SSH_MSG_IGNORE packet. The IGNORE packet contains a
3374 * string long enough to make the total length of the two
3375 * packets constant. This should ensure that a passive
3376 * listener doing traffic analyis can't work out the length
3377 * of the password.
3378 *
3379 * For this to work, we need an assumption about the
3380 * maximum length of the password packet. I think 256 is
3381 * pretty conservative. Anyone using a password longer than
3382 * that probably doesn't have much to worry about from
3383 * people who find out how long their password is!
3384 */
3385 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
3386 ssh2_pkt_addstring(username);
3387 ssh2_pkt_addstring("ssh-connection"); /* service requested */
3388 ssh2_pkt_addstring("password");
3389 ssh2_pkt_addbool(FALSE);
3390 ssh2_pkt_addstring(password);
3391 ssh2_pkt_defer();
3392 /*
3393 * We'll include a string that's an exact multiple of the
3394 * cipher block size. If the cipher is NULL for some
3395 * reason, we don't do this trick at all because we gain
3396 * nothing by it.
3397 */
3398 if (cscipher) {
3399 int stringlen, i;
3400
3401 stringlen = (256 - deferred_len);
3402 stringlen += cscipher->blksize - 1;
3403 stringlen -= (stringlen % cscipher->blksize);
3404 if (cscomp) {
3405 /*
3406 * Temporarily disable actual compression,
3407 * so we can guarantee to get this string
3408 * exactly the length we want it. The
3409 * compression-disabling routine should
3410 * return an integer indicating how many
3411 * bytes we should adjust our string length
3412 * by.
3413 */
3414 stringlen -= cscomp->disable_compression();
3415 }
3416 ssh2_pkt_init(SSH2_MSG_IGNORE);
3417 ssh2_pkt_addstring_start();
3418 for (i = 0; i < stringlen; i++) {
3419 char c = (char)random_byte();
3420 ssh2_pkt_addstring_data(&c, 1);
3421 }
3422 ssh2_pkt_defer();
3423 }
3424 ssh_pkt_defersend();
3425 logevent("Sent password");
3426 type = AUTH_TYPE_PASSWORD;
3427 } else {
3428 c_write_str("No supported authentication methods left to try!\r\n");
3429 logevent("No supported authentications offered. Disconnecting");
3430 ssh2_pkt_init(SSH2_MSG_DISCONNECT);
3431 ssh2_pkt_adduint32(SSH2_DISCONNECT_BY_APPLICATION);
3432 ssh2_pkt_addstring("No supported authentication methods available");
3433 ssh2_pkt_addstring("en"); /* language tag */
3434 ssh2_pkt_send();
3435 ssh_state = SSH_STATE_CLOSED;
3436 crReturnV;
3437 }
3438 }
3439 } while (!we_are_in);
3440
3441 /*
3442 * Now we're authenticated for the connection protocol. The
3443 * connection protocol will automatically have started at this
3444 * point; there's no need to send SERVICE_REQUEST.
3445 */
3446
3447 /*
3448 * So now create a channel with a session in it.
3449 */
3450 mainchan = smalloc(sizeof(struct ssh_channel));
3451 mainchan->localid = 100; /* as good as any */
3452 ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN);
3453 ssh2_pkt_addstring("session");
3454 ssh2_pkt_adduint32(mainchan->localid);
3455 ssh2_pkt_adduint32(0x8000UL); /* our window size */
3456 ssh2_pkt_adduint32(0x4000UL); /* our max pkt size */
3457 ssh2_pkt_send();
3458 crWaitUntilV(ispkt);
3459 if (pktin.type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
3460 bombout(("Server refused to open a session"));
3461 crReturnV;
3462 /* FIXME: error data comes back in FAILURE packet */
3463 }
3464 if (ssh2_pkt_getuint32() != mainchan->localid) {
3465 bombout(("Server's channel confirmation cited wrong channel"));
3466 crReturnV;
3467 }
3468 mainchan->remoteid = ssh2_pkt_getuint32();
3469 mainchan->type = CHAN_MAINSESSION;
3470 mainchan->closes = 0;
3471 mainchan->v2.remwindow = ssh2_pkt_getuint32();
3472 mainchan->v2.remmaxpkt = ssh2_pkt_getuint32();
3473 mainchan->v2.outbuffer = NULL;
3474 mainchan->v2.outbuflen = mainchan->v2.outbufsize = 0;
3475 ssh_channels = newtree234(ssh_channelcmp);
3476 add234(ssh_channels, mainchan);
3477 logevent("Opened channel for session");
3478
3479 /*
3480 * Potentially enable X11 forwarding.
3481 */
3482 if (cfg.x11_forward) {
3483 char proto[20], data[64];
3484 logevent("Requesting X11 forwarding");
3485 x11_invent_auth(proto, sizeof(proto), data, sizeof(data));
3486 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
3487 ssh2_pkt_adduint32(mainchan->remoteid);
3488 ssh2_pkt_addstring("x11-req");
3489 ssh2_pkt_addbool(1); /* want reply */
3490 ssh2_pkt_addbool(0); /* many connections */
3491 ssh2_pkt_addstring(proto);
3492 ssh2_pkt_addstring(data);
3493 ssh2_pkt_adduint32(0); /* screen number */
3494 ssh2_pkt_send();
3495
3496 do {
3497 crWaitUntilV(ispkt);
3498 if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
3499 unsigned i = ssh2_pkt_getuint32();
3500 struct ssh_channel *c;
3501 c = find234(ssh_channels, &i, ssh_channelfind);
3502 if (!c)
3503 continue; /* nonexistent channel */
3504 c->v2.remwindow += ssh2_pkt_getuint32();
3505 }
3506 } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
3507
3508 if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
3509 if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
3510 bombout(("Server got confused by X11 forwarding request"));
3511 crReturnV;
3512 }
3513 logevent("X11 forwarding refused");
3514 } else {
3515 logevent("X11 forwarding enabled");
3516 ssh_X11_fwd_enabled = TRUE;
3517 }
3518 }
3519
3520 /*
3521 * Potentially enable agent forwarding.
3522 */
3523 if (cfg.agentfwd && agent_exists()) {
3524 logevent("Requesting OpenSSH-style agent forwarding");
3525 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
3526 ssh2_pkt_adduint32(mainchan->remoteid);
3527 ssh2_pkt_addstring("auth-agent-req@openssh.com");
3528 ssh2_pkt_addbool(1); /* want reply */
3529 ssh2_pkt_send();
3530
3531 do {
3532 crWaitUntilV(ispkt);
3533 if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
3534 unsigned i = ssh2_pkt_getuint32();
3535 struct ssh_channel *c;
3536 c = find234(ssh_channels, &i, ssh_channelfind);
3537 if (!c)
3538 continue; /* nonexistent channel */
3539 c->v2.remwindow += ssh2_pkt_getuint32();
3540 }
3541 } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
3542
3543 if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
3544 if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
3545 bombout(("Server got confused by agent forwarding request"));
3546 crReturnV;
3547 }
3548 logevent("Agent forwarding refused");
3549 } else {
3550 logevent("Agent forwarding enabled");
3551 ssh_agentfwd_enabled = TRUE;
3552 }
3553 }
3554
3555 /*
3556 * Now allocate a pty for the session.
3557 */
3558 if (!cfg.nopty) {
3559 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
3560 ssh2_pkt_adduint32(mainchan->remoteid); /* recipient channel */
3561 ssh2_pkt_addstring("pty-req");
3562 ssh2_pkt_addbool(1); /* want reply */
3563 ssh2_pkt_addstring(cfg.termtype);
3564 ssh2_pkt_adduint32(cols);
3565 ssh2_pkt_adduint32(rows);
3566 ssh2_pkt_adduint32(0); /* pixel width */
3567 ssh2_pkt_adduint32(0); /* pixel height */
3568 ssh2_pkt_addstring_start();
3569 ssh2_pkt_addstring_data("\0", 1);/* TTY_OP_END, no special options */
3570 ssh2_pkt_send();
3571 ssh_state = SSH_STATE_INTERMED;
3572
3573 do {
3574 crWaitUntilV(ispkt);
3575 if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
3576 unsigned i = ssh2_pkt_getuint32();
3577 struct ssh_channel *c;
3578 c = find234(ssh_channels, &i, ssh_channelfind);
3579 if (!c)
3580 continue; /* nonexistent channel */
3581 c->v2.remwindow += ssh2_pkt_getuint32();
3582 }
3583 } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
3584
3585 if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
3586 if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
3587 bombout(("Server got confused by pty request"));
3588 crReturnV;
3589 }
3590 c_write_str("Server refused to allocate pty\r\n");
3591 ssh_editing = ssh_echoing = 1;
3592 } else {
3593 logevent("Allocated pty");
3594 }
3595 } else {
3596 ssh_editing = ssh_echoing = 1;
3597 }
3598
3599 /*
3600 * Start a shell or a remote command.
3601 */
3602 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
3603 ssh2_pkt_adduint32(mainchan->remoteid); /* recipient channel */
3604 if (cfg.ssh_subsys) {
3605 ssh2_pkt_addstring("subsystem");
3606 ssh2_pkt_addbool(1); /* want reply */
3607 ssh2_pkt_addstring(cfg.remote_cmd_ptr);
3608 } else if (*cfg.remote_cmd_ptr) {
3609 ssh2_pkt_addstring("exec");
3610 ssh2_pkt_addbool(1); /* want reply */
3611 ssh2_pkt_addstring(cfg.remote_cmd_ptr);
3612 } else {
3613 ssh2_pkt_addstring("shell");
3614 ssh2_pkt_addbool(1); /* want reply */
3615 }
3616 ssh2_pkt_send();
3617 do {
3618 crWaitUntilV(ispkt);
3619 if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
3620 unsigned i = ssh2_pkt_getuint32();
3621 struct ssh_channel *c;
3622 c = find234(ssh_channels, &i, ssh_channelfind);
3623 if (!c)
3624 continue; /* nonexistent channel */
3625 c->v2.remwindow += ssh2_pkt_getuint32();
3626 }
3627 } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
3628 if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
3629 if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
3630 bombout(("Server got confused by shell/command request"));
3631 crReturnV;
3632 }
3633 bombout(("Server refused to start a shell/command"));
3634 crReturnV;
3635 } else {
3636 logevent("Started a shell/command");
3637 }
3638
3639 ssh_state = SSH_STATE_SESSION;
3640 if (size_needed)
3641 ssh_size();
3642 if (eof_needed)
3643 ssh_special(TS_EOF);
3644
3645 /*
3646 * Transfer data!
3647 */
3648 ldisc_send(NULL, 0); /* cause ldisc to notice changes */
3649 ssh_send_ok = 1;
3650 while (1) {
3651 static int try_send;
3652 crReturnV;
3653 try_send = FALSE;
3654 if (ispkt) {
3655 if (pktin.type == SSH2_MSG_CHANNEL_DATA ||
3656 pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA) {
3657 char *data;
3658 int length;
3659 unsigned i = ssh2_pkt_getuint32();
3660 struct ssh_channel *c;
3661 c = find234(ssh_channels, &i, ssh_channelfind);
3662 if (!c)
3663 continue; /* nonexistent channel */
3664 if (pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
3665 ssh2_pkt_getuint32() != SSH2_EXTENDED_DATA_STDERR)
3666 continue; /* extended but not stderr */
3667 ssh2_pkt_getstring(&data, &length);
3668 if (data) {
3669 switch (c->type) {
3670 case CHAN_MAINSESSION:
3671 from_backend(pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA,
3672 data, length);
3673 break;
3674 case CHAN_X11:
3675 x11_send(c->u.x11.s, data, length);
3676 break;
3677 case CHAN_AGENT:
3678 while (length > 0) {
3679 if (c->u.a.lensofar < 4) {
3680 int l = min(4 - c->u.a.lensofar, length);
3681 memcpy(c->u.a.msglen + c->u.a.lensofar, data, l);
3682 data += l; length -= l; c->u.a.lensofar += l;
3683 }
3684 if (c->u.a.lensofar == 4) {
3685 c->u.a.totallen = 4 + GET_32BIT(c->u.a.msglen);
3686 c->u.a.message = smalloc(c->u.a.totallen);
3687 memcpy(c->u.a.message, c->u.a.msglen, 4);
3688 }
3689 if (c->u.a.lensofar >= 4 && length > 0) {
3690 int l = min(c->u.a.totallen - c->u.a.lensofar,
3691 length);
3692 memcpy(c->u.a.message + c->u.a.lensofar, data, l);
3693 data += l; length -= l; c->u.a.lensofar += l;
3694 }
3695 if (c->u.a.lensofar == c->u.a.totallen) {
3696 void *reply, *sentreply;
3697 int replylen;
3698 agent_query(c->u.a.message, c->u.a.totallen,
3699 &reply, &replylen);
3700 if (reply)
3701 sentreply = reply;
3702 else {
3703 /* Fake SSH_AGENT_FAILURE. */
3704 sentreply = "\0\0\0\1\5";
3705 replylen = 5;
3706 }
3707 ssh2_add_channel_data(c, sentreply, replylen);
3708 try_send = TRUE;
3709 if (reply)
3710 sfree(reply);
3711 sfree(c->u.a.message);
3712 c->u.a.lensofar = 0;
3713 }
3714 }
3715 break;
3716 }
3717 /*
3718 * Enlarge the window again at the remote
3719 * side, just in case it ever runs down and
3720 * they fail to send us any more data.
3721 */
3722 ssh2_pkt_init(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
3723 ssh2_pkt_adduint32(c->remoteid);
3724 ssh2_pkt_adduint32(length);
3725 ssh2_pkt_send();
3726 }
3727 } else if (pktin.type == SSH2_MSG_DISCONNECT) {
3728 ssh_state = SSH_STATE_CLOSED;
3729 logevent("Received disconnect message");
3730 crReturnV;
3731 } else if (pktin.type == SSH2_MSG_CHANNEL_REQUEST) {
3732 continue; /* exit status et al; ignore (FIXME?) */
3733 } else if (pktin.type == SSH2_MSG_CHANNEL_EOF) {
3734 unsigned i = ssh2_pkt_getuint32();
3735 struct ssh_channel *c;
3736
3737 c = find234(ssh_channels, &i, ssh_channelfind);
3738 if (!c)
3739 continue; /* nonexistent channel */
3740
3741 if (c->type == CHAN_X11) {
3742 /*
3743 * Remote EOF on an X11 channel means we should
3744 * wrap up and close the channel ourselves.
3745 */
3746 x11_close(c->u.x11.s);
3747 sshfwd_close(c);
3748 } else if (c->type == CHAN_AGENT) {
3749 sshfwd_close(c);
3750 }
3751 } else if (pktin.type == SSH2_MSG_CHANNEL_CLOSE) {
3752 unsigned i = ssh2_pkt_getuint32();
3753 struct ssh_channel *c;
3754 enum234 e;
3755
3756 c = find234(ssh_channels, &i, ssh_channelfind);
3757 if (!c)
3758 continue; /* nonexistent channel */
3759 if (c->closes == 0) {
3760 ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE);
3761 ssh2_pkt_adduint32(c->remoteid);
3762 ssh2_pkt_send();
3763 }
3764 /* Do pre-close processing on the channel. */
3765 switch (c->type) {
3766 case CHAN_MAINSESSION:
3767 break; /* nothing to see here, move along */
3768 case CHAN_X11:
3769 break;
3770 case CHAN_AGENT:
3771 break;
3772 }
3773 del234(ssh_channels, c);
3774 sfree(c->v2.outbuffer);
3775 sfree(c);
3776
3777 /*
3778 * See if that was the last channel left open.
3779 */
3780 c = first234(ssh_channels, &e);
3781 if (!c) {
3782 logevent("All channels closed. Disconnecting");
3783 ssh2_pkt_init(SSH2_MSG_DISCONNECT);
3784 ssh2_pkt_adduint32(SSH2_DISCONNECT_BY_APPLICATION);
3785 ssh2_pkt_addstring("All open channels closed");
3786 ssh2_pkt_addstring("en"); /* language tag */
3787 ssh2_pkt_send();
3788 ssh_state = SSH_STATE_CLOSED;
3789 crReturnV;
3790 }
3791 continue; /* remote sends close; ignore (FIXME) */
3792 } else if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
3793 unsigned i = ssh2_pkt_getuint32();
3794 struct ssh_channel *c;
3795 c = find234(ssh_channels, &i, ssh_channelfind);
3796 if (!c)
3797 continue; /* nonexistent channel */
3798 c->v2.remwindow += ssh2_pkt_getuint32();
3799 try_send = TRUE;
3800 } else if (pktin.type == SSH2_MSG_CHANNEL_OPEN) {
3801 char *type;
3802 int typelen;
3803 char *error = NULL;
3804 struct ssh_channel *c;
3805 ssh2_pkt_getstring(&type, &typelen);
3806 c = smalloc(sizeof(struct ssh_channel));
3807
3808 if (typelen == 3 && !memcmp(type, "x11", 3)) {
3809 if (!ssh_X11_fwd_enabled)
3810 error = "X11 forwarding is not enabled";
3811 else if ( x11_init(&c->u.x11.s, cfg.x11_display, c) != NULL ) {
3812 error = "Unable to open an X11 connection";
3813 } else {
3814 c->type = CHAN_X11;
3815 }
3816 } else if (typelen == 22 &&
3817 !memcmp(type, "auth-agent@openssh.com", 3)) {
3818 if (!ssh_agentfwd_enabled)
3819 error = "Agent forwarding is not enabled";
3820 else {
3821 c->type = CHAN_AGENT; /* identify channel type */
3822 c->u.a.lensofar = 0;
3823 }
3824 } else {
3825 error = "Unsupported channel type requested";
3826 }
3827
3828 c->remoteid = ssh2_pkt_getuint32();
3829 if (error) {
3830 ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_FAILURE);
3831 ssh2_pkt_adduint32(c->remoteid);
3832 ssh2_pkt_adduint32(SSH2_OPEN_CONNECT_FAILED);
3833 ssh2_pkt_addstring(error);
3834 ssh2_pkt_addstring("en"); /* language tag */
3835 ssh2_pkt_send();
3836 sfree(c);
3837 } else {
3838 struct ssh_channel *d;
3839 unsigned i;
3840 enum234 e;
3841
3842 for (i=1, d = first234(ssh_channels, &e); d;
3843 d = next234(&e)) {
3844 if (d->localid > i)
3845 break; /* found a free number */
3846 i = d->localid + 1;
3847 }
3848 c->localid = i;
3849 c->closes = 0;
3850 c->v2.remwindow = ssh2_pkt_getuint32();
3851 c->v2.remmaxpkt = ssh2_pkt_getuint32();
3852 c->v2.outbuffer = NULL;
3853 c->v2.outbuflen = c->v2.outbufsize = 0;
3854 add234(ssh_channels, c);
3855 ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
3856 ssh2_pkt_adduint32(c->remoteid);
3857 ssh2_pkt_adduint32(c->localid);
3858 ssh2_pkt_adduint32(0x8000UL); /* our window size */
3859 ssh2_pkt_adduint32(0x4000UL); /* our max pkt size */
3860 ssh2_pkt_send();
3861 }
3862 } else {
3863 bombout(("Strange packet received: type %d", pktin.type));
3864 crReturnV;
3865 }
3866 } else {
3867 /*
3868 * We have spare data. Add it to the channel buffer.
3869 */
3870 ssh2_add_channel_data(mainchan, in, inlen);
3871 try_send = TRUE;
3872 }
3873 if (try_send) {
3874 enum234 e;
3875 struct ssh_channel *c;
3876 /*
3877 * Try to send data on all channels if we can.
3878 */
3879 for (c = first234(ssh_channels, &e); c; c = next234(&e))
3880 ssh2_try_send(c);
3881 }
3882 }
3883
3884 crFinishV;
3885 }
3886
3887 /*
3888 * Handle the top-level SSH2 protocol.
3889 */
3890 static void ssh2_protocol(unsigned char *in, int inlen, int ispkt)
3891 {
3892 if (do_ssh2_transport(in, inlen, ispkt) == 0)
3893 return;
3894 do_ssh2_authconn(in, inlen, ispkt);
3895 }
3896
3897 /*
3898 * Called to set up the connection.
3899 *
3900 * Returns an error message, or NULL on success.
3901 */
3902 static char *ssh_init (char *host, int port, char **realhost) {
3903 char *p;
3904
3905 #ifdef MSCRYPTOAPI
3906 if(crypto_startup() == 0)
3907 return "Microsoft high encryption pack not installed!";
3908 #endif
3909
3910 ssh_send_ok = 0;
3911 ssh_editing = 0;
3912 ssh_echoing = 0;
3913
3914 p = connect_to_host(host, port, realhost);
3915 if (p != NULL)
3916 return p;
3917
3918 return NULL;
3919 }
3920
3921 /*
3922 * Called to send data down the Telnet connection.
3923 */
3924 static void ssh_send (char *buf, int len) {
3925 if (s == NULL || ssh_protocol == NULL)
3926 return;
3927
3928 ssh_protocol(buf, len, 0);
3929 }
3930
3931 /*
3932 * Called to set the size of the window from SSH's POV.
3933 */
3934 static void ssh_size(void) {
3935 switch (ssh_state) {
3936 case SSH_STATE_BEFORE_SIZE:
3937 case SSH_STATE_PREPACKET:
3938 case SSH_STATE_CLOSED:
3939 break; /* do nothing */
3940 case SSH_STATE_INTERMED:
3941 size_needed = TRUE; /* buffer for later */
3942 break;
3943 case SSH_STATE_SESSION:
3944 if (!cfg.nopty) {
3945 if (ssh_version == 1) {
3946 send_packet(SSH1_CMSG_WINDOW_SIZE,
3947 PKT_INT, rows, PKT_INT, cols,
3948 PKT_INT, 0, PKT_INT, 0, PKT_END);
3949 } else {
3950 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
3951 ssh2_pkt_adduint32(mainchan->remoteid);
3952 ssh2_pkt_addstring("window-change");
3953 ssh2_pkt_addbool(0);
3954 ssh2_pkt_adduint32(cols);
3955 ssh2_pkt_adduint32(rows);
3956 ssh2_pkt_adduint32(0);
3957 ssh2_pkt_adduint32(0);
3958 ssh2_pkt_send();
3959 }
3960 }
3961 break;
3962 }
3963 }
3964
3965 /*
3966 * Send Telnet special codes. TS_EOF is useful for `plink', so you
3967 * can send an EOF and collect resulting output (e.g. `plink
3968 * hostname sort').
3969 */
3970 static void ssh_special (Telnet_Special code) {
3971 if (code == TS_EOF) {
3972 if (ssh_state != SSH_STATE_SESSION) {
3973 /*
3974 * Buffer the EOF in case we are pre-SESSION, so we can
3975 * send it as soon as we reach SESSION.
3976 */
3977 if (code == TS_EOF)
3978 eof_needed = TRUE;
3979 return;
3980 }
3981 if (ssh_version == 1) {
3982 send_packet(SSH1_CMSG_EOF, PKT_END);
3983 } else {
3984 ssh2_pkt_init(SSH2_MSG_CHANNEL_EOF);
3985 ssh2_pkt_adduint32(mainchan->remoteid);
3986 ssh2_pkt_send();
3987 }
3988 logevent("Sent EOF message");
3989 } else if (code == TS_PING) {
3990 if (ssh_state == SSH_STATE_CLOSED || ssh_state == SSH_STATE_PREPACKET)
3991 return;
3992 if (ssh_version == 1) {
3993 send_packet(SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
3994 } else {
3995 ssh2_pkt_init(SSH2_MSG_IGNORE);
3996 ssh2_pkt_addstring_start();
3997 ssh2_pkt_send();
3998 }
3999 } else {
4000 /* do nothing */
4001 }
4002 }
4003
4004 static Socket ssh_socket(void) { return s; }
4005
4006 static int ssh_sendok(void) { return ssh_send_ok; }
4007
4008 static int ssh_ldisc(int option) {
4009 if (option == LD_ECHO) return ssh_echoing;
4010 if (option == LD_EDIT) return ssh_editing;
4011 return FALSE;
4012 }
4013
4014 Backend ssh_backend = {
4015 ssh_init,
4016 ssh_send,
4017 ssh_size,
4018 ssh_special,
4019 ssh_socket,
4020 ssh_sendok,
4021 ssh_ldisc,
4022 22
4023 };
Simon Tatham's PuTTY GUI SSH client; import of svn://svn.tartarus.org/sgt/putty