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[u/mdw/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, sk_close(s), \
23 s = NULL, connection_fatal msg )
24
25 #define SSH1_MSG_DISCONNECT 1 /* 0x1 */
26 #define SSH1_SMSG_PUBLIC_KEY 2 /* 0x2 */
27 #define SSH1_CMSG_SESSION_KEY 3 /* 0x3 */
28 #define SSH1_CMSG_USER 4 /* 0x4 */
29 #define SSH1_CMSG_AUTH_RSA 6 /* 0x6 */
30 #define SSH1_SMSG_AUTH_RSA_CHALLENGE 7 /* 0x7 */
31 #define SSH1_CMSG_AUTH_RSA_RESPONSE 8 /* 0x8 */
32 #define SSH1_CMSG_AUTH_PASSWORD 9 /* 0x9 */
33 #define SSH1_CMSG_REQUEST_PTY 10 /* 0xa */
34 #define SSH1_CMSG_WINDOW_SIZE 11 /* 0xb */
35 #define SSH1_CMSG_EXEC_SHELL 12 /* 0xc */
36 #define SSH1_CMSG_EXEC_CMD 13 /* 0xd */
37 #define SSH1_SMSG_SUCCESS 14 /* 0xe */
38 #define SSH1_SMSG_FAILURE 15 /* 0xf */
39 #define SSH1_CMSG_STDIN_DATA 16 /* 0x10 */
40 #define SSH1_SMSG_STDOUT_DATA 17 /* 0x11 */
41 #define SSH1_SMSG_STDERR_DATA 18 /* 0x12 */
42 #define SSH1_CMSG_EOF 19 /* 0x13 */
43 #define SSH1_SMSG_EXIT_STATUS 20 /* 0x14 */
44 #define SSH1_MSG_CHANNEL_OPEN_CONFIRMATION 21 /* 0x15 */
45 #define SSH1_MSG_CHANNEL_OPEN_FAILURE 22 /* 0x16 */
46 #define SSH1_MSG_CHANNEL_DATA 23 /* 0x17 */
47 #define SSH1_MSG_CHANNEL_CLOSE 24 /* 0x18 */
48 #define SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION 25 /* 0x19 */
49 #define SSH1_CMSG_AGENT_REQUEST_FORWARDING 30 /* 0x1e */
50 #define SSH1_SMSG_AGENT_OPEN 31 /* 0x1f */
51 #define SSH1_CMSG_EXIT_CONFIRMATION 33 /* 0x21 */
52 #define SSH1_MSG_IGNORE 32 /* 0x20 */
53 #define SSH1_MSG_DEBUG 36 /* 0x24 */
54 #define SSH1_CMSG_REQUEST_COMPRESSION 37 /* 0x25 */
55 #define SSH1_CMSG_AUTH_TIS 39 /* 0x27 */
56 #define SSH1_SMSG_AUTH_TIS_CHALLENGE 40 /* 0x28 */
57 #define SSH1_CMSG_AUTH_TIS_RESPONSE 41 /* 0x29 */
58 #define SSH1_CMSG_AUTH_CCARD 70 /* 0x46 */
59 #define SSH1_SMSG_AUTH_CCARD_CHALLENGE 71 /* 0x47 */
60 #define SSH1_CMSG_AUTH_CCARD_RESPONSE 72 /* 0x48 */
61
62 #define SSH1_AUTH_TIS 5 /* 0x5 */
63 #define SSH1_AUTH_CCARD 16 /* 0x10 */
64
65 #define SSH_AGENTC_REQUEST_RSA_IDENTITIES 1 /* 0x1 */
66 #define SSH_AGENT_RSA_IDENTITIES_ANSWER 2 /* 0x2 */
67 #define SSH_AGENTC_RSA_CHALLENGE 3 /* 0x3 */
68 #define SSH_AGENT_RSA_RESPONSE 4 /* 0x4 */
69 #define SSH_AGENT_FAILURE 5 /* 0x5 */
70 #define SSH_AGENT_SUCCESS 6 /* 0x6 */
71 #define SSH_AGENTC_ADD_RSA_IDENTITY 7 /* 0x7 */
72 #define SSH_AGENTC_REMOVE_RSA_IDENTITY 8 /* 0x8 */
73
74 #define SSH2_MSG_DISCONNECT 1 /* 0x1 */
75 #define SSH2_MSG_IGNORE 2 /* 0x2 */
76 #define SSH2_MSG_UNIMPLEMENTED 3 /* 0x3 */
77 #define SSH2_MSG_DEBUG 4 /* 0x4 */
78 #define SSH2_MSG_SERVICE_REQUEST 5 /* 0x5 */
79 #define SSH2_MSG_SERVICE_ACCEPT 6 /* 0x6 */
80 #define SSH2_MSG_KEXINIT 20 /* 0x14 */
81 #define SSH2_MSG_NEWKEYS 21 /* 0x15 */
82 #define SSH2_MSG_KEXDH_INIT 30 /* 0x1e */
83 #define SSH2_MSG_KEXDH_REPLY 31 /* 0x1f */
84 #define SSH2_MSG_USERAUTH_REQUEST 50 /* 0x32 */
85 #define SSH2_MSG_USERAUTH_FAILURE 51 /* 0x33 */
86 #define SSH2_MSG_USERAUTH_SUCCESS 52 /* 0x34 */
87 #define SSH2_MSG_USERAUTH_BANNER 53 /* 0x35 */
88 #define SSH2_MSG_USERAUTH_PK_OK 60 /* 0x3c */
89 #define SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ 60 /* 0x3c */
90 #define SSH2_MSG_GLOBAL_REQUEST 80 /* 0x50 */
91 #define SSH2_MSG_REQUEST_SUCCESS 81 /* 0x51 */
92 #define SSH2_MSG_REQUEST_FAILURE 82 /* 0x52 */
93 #define SSH2_MSG_CHANNEL_OPEN 90 /* 0x5a */
94 #define SSH2_MSG_CHANNEL_OPEN_CONFIRMATION 91 /* 0x5b */
95 #define SSH2_MSG_CHANNEL_OPEN_FAILURE 92 /* 0x5c */
96 #define SSH2_MSG_CHANNEL_WINDOW_ADJUST 93 /* 0x5d */
97 #define SSH2_MSG_CHANNEL_DATA 94 /* 0x5e */
98 #define SSH2_MSG_CHANNEL_EXTENDED_DATA 95 /* 0x5f */
99 #define SSH2_MSG_CHANNEL_EOF 96 /* 0x60 */
100 #define SSH2_MSG_CHANNEL_CLOSE 97 /* 0x61 */
101 #define SSH2_MSG_CHANNEL_REQUEST 98 /* 0x62 */
102 #define SSH2_MSG_CHANNEL_SUCCESS 99 /* 0x63 */
103 #define SSH2_MSG_CHANNEL_FAILURE 100 /* 0x64 */
104
105 #define SSH2_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT 1 /* 0x1 */
106 #define SSH2_DISCONNECT_PROTOCOL_ERROR 2 /* 0x2 */
107 #define SSH2_DISCONNECT_KEY_EXCHANGE_FAILED 3 /* 0x3 */
108 #define SSH2_DISCONNECT_HOST_AUTHENTICATION_FAILED 4 /* 0x4 */
109 #define SSH2_DISCONNECT_MAC_ERROR 5 /* 0x5 */
110 #define SSH2_DISCONNECT_COMPRESSION_ERROR 6 /* 0x6 */
111 #define SSH2_DISCONNECT_SERVICE_NOT_AVAILABLE 7 /* 0x7 */
112 #define SSH2_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED 8 /* 0x8 */
113 #define SSH2_DISCONNECT_HOST_KEY_NOT_VERIFIABLE 9 /* 0x9 */
114 #define SSH2_DISCONNECT_CONNECTION_LOST 10 /* 0xa */
115 #define SSH2_DISCONNECT_BY_APPLICATION 11 /* 0xb */
116
117 #define SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED 1 /* 0x1 */
118 #define SSH2_OPEN_CONNECT_FAILED 2 /* 0x2 */
119 #define SSH2_OPEN_UNKNOWN_CHANNEL_TYPE 3 /* 0x3 */
120 #define SSH2_OPEN_RESOURCE_SHORTAGE 4 /* 0x4 */
121
122 #define SSH2_EXTENDED_DATA_STDERR 1 /* 0x1 */
123
124 #define GET_32BIT(cp) \
125 (((unsigned long)(unsigned char)(cp)[0] << 24) | \
126 ((unsigned long)(unsigned char)(cp)[1] << 16) | \
127 ((unsigned long)(unsigned char)(cp)[2] << 8) | \
128 ((unsigned long)(unsigned char)(cp)[3]))
129
130 #define PUT_32BIT(cp, value) { \
131 (cp)[0] = (unsigned char)((value) >> 24); \
132 (cp)[1] = (unsigned char)((value) >> 16); \
133 (cp)[2] = (unsigned char)((value) >> 8); \
134 (cp)[3] = (unsigned char)(value); }
135
136 enum { PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR, PKT_BIGNUM };
137
138 /* Coroutine mechanics for the sillier bits of the code */
139 #define crBegin1 static int crLine = 0;
140 #define crBegin2 switch(crLine) { case 0:;
141 #define crBegin crBegin1; crBegin2;
142 #define crFinish(z) } crLine = 0; return (z)
143 #define crFinishV } crLine = 0; return
144 #define crReturn(z) \
145 do {\
146 crLine=__LINE__; return (z); case __LINE__:;\
147 } while (0)
148 #define crReturnV \
149 do {\
150 crLine=__LINE__; return; case __LINE__:;\
151 } while (0)
152 #define crStop(z) do{ crLine = 0; return (z); }while(0)
153 #define crStopV do{ crLine = 0; return; }while(0)
154 #define crWaitUntil(c) do { crReturn(0); } while (!(c))
155 #define crWaitUntilV(c) do { crReturnV; } while (!(c))
156
157 extern const struct ssh_cipher ssh_3des;
158 extern const struct ssh_cipher ssh_3des_ssh2;
159 extern const struct ssh_cipher ssh_des;
160 extern const struct ssh_cipher ssh_blowfish_ssh1;
161 extern const struct ssh_cipher ssh_blowfish_ssh2;
162
163 /*
164 * Ciphers for SSH2. We miss out single-DES because it isn't
165 * supported; also 3DES and Blowfish are both done differently from
166 * SSH1. (3DES uses outer chaining; Blowfish has the opposite
167 * endianness and different-sized keys.)
168 */
169 const static struct ssh_cipher *ciphers[] = { &ssh_blowfish_ssh2, &ssh_3des_ssh2 };
170
171 extern const struct ssh_kex ssh_diffiehellman;
172 const static struct ssh_kex *kex_algs[] = { &ssh_diffiehellman };
173
174 extern const struct ssh_hostkey ssh_dss;
175 const static struct ssh_hostkey *hostkey_algs[] = { &ssh_dss };
176
177 extern const struct ssh_mac ssh_md5, ssh_sha1, ssh_sha1_buggy;
178
179 static void nullmac_key(unsigned char *key) { }
180 static void nullmac_generate(unsigned char *blk, int len, unsigned long seq) { }
181 static int nullmac_verify(unsigned char *blk, int len, unsigned long seq) { return 1; }
182 const static struct ssh_mac ssh_mac_none = {
183 nullmac_key, nullmac_key, nullmac_generate, nullmac_verify, "none", 0
184 };
185 const static struct ssh_mac *macs[] = {
186 &ssh_sha1, &ssh_md5, &ssh_mac_none };
187 const static struct ssh_mac *buggymacs[] = {
188 &ssh_sha1_buggy, &ssh_md5, &ssh_mac_none };
189
190 static void ssh_comp_none_init(void) { }
191 static int ssh_comp_none_block(unsigned char *block, int len,
192 unsigned char **outblock, int *outlen) {
193 return 0;
194 }
195 const static struct ssh_compress ssh_comp_none = {
196 "none",
197 ssh_comp_none_init, ssh_comp_none_block,
198 ssh_comp_none_init, ssh_comp_none_block
199 };
200 extern const struct ssh_compress ssh_zlib;
201 const static struct ssh_compress *compressions[] = {
202 &ssh_zlib, &ssh_comp_none };
203
204 /*
205 * 2-3-4 tree storing channels.
206 */
207 struct ssh_channel {
208 unsigned remoteid, localid;
209 int type;
210 int closes;
211 union {
212 struct ssh_agent_channel {
213 unsigned char *message;
214 unsigned char msglen[4];
215 int lensofar, totallen;
216 } a;
217 struct ssh2_data_channel {
218 unsigned char *outbuffer;
219 unsigned outbuflen, outbufsize;
220 unsigned remwindow, remmaxpkt;
221 } v2;
222 } u;
223 };
224
225 struct Packet {
226 long length;
227 int type;
228 unsigned char *data;
229 unsigned char *body;
230 long savedpos;
231 long maxlen;
232 };
233
234 static SHA_State exhash;
235
236 static Socket s = NULL;
237
238 static unsigned char session_key[32];
239 static int ssh1_compressing;
240 static int ssh_agentfwd_enabled;
241 static const struct ssh_cipher *cipher = NULL;
242 static const struct ssh_cipher *cscipher = NULL;
243 static const struct ssh_cipher *sccipher = NULL;
244 static const struct ssh_mac *csmac = NULL;
245 static const struct ssh_mac *scmac = NULL;
246 static const struct ssh_compress *cscomp = NULL;
247 static const struct ssh_compress *sccomp = NULL;
248 static const struct ssh_kex *kex = NULL;
249 static const struct ssh_hostkey *hostkey = NULL;
250 int (*ssh_get_password)(const char *prompt, char *str, int maxlen) = NULL;
251
252 static char *savedhost;
253 static int savedport;
254 static int ssh_send_ok;
255
256 static tree234 *ssh_channels; /* indexed by local id */
257 static struct ssh_channel *mainchan; /* primary session channel */
258
259 static enum {
260 SSH_STATE_BEFORE_SIZE,
261 SSH_STATE_INTERMED,
262 SSH_STATE_SESSION,
263 SSH_STATE_CLOSED
264 } ssh_state = SSH_STATE_BEFORE_SIZE;
265
266 static int size_needed = FALSE;
267
268 static struct Packet pktin = { 0, 0, NULL, NULL, 0 };
269 static struct Packet pktout = { 0, 0, NULL, NULL, 0 };
270
271 static int ssh_version;
272 static void (*ssh_protocol)(unsigned char *in, int inlen, int ispkt);
273 static void ssh1_protocol(unsigned char *in, int inlen, int ispkt);
274 static void ssh2_protocol(unsigned char *in, int inlen, int ispkt);
275 static void ssh_size(void);
276
277 static int (*s_rdpkt)(unsigned char **data, int *datalen);
278
279 static struct rdpkt1_state_tag {
280 long len, pad, biglen, to_read;
281 unsigned long realcrc, gotcrc;
282 unsigned char *p;
283 int i;
284 int chunk;
285 } rdpkt1_state;
286
287 static struct rdpkt2_state_tag {
288 long len, pad, payload, packetlen, maclen;
289 int i;
290 int cipherblk;
291 unsigned long incoming_sequence;
292 } rdpkt2_state;
293
294 static int ssh_channelcmp(void *av, void *bv) {
295 struct ssh_channel *a = (struct ssh_channel *)av;
296 struct ssh_channel *b = (struct ssh_channel *)bv;
297 if (a->localid < b->localid) return -1;
298 if (a->localid > b->localid) return +1;
299 return 0;
300 }
301 static int ssh_channelfind(void *av, void *bv) {
302 unsigned *a = (unsigned *)av;
303 struct ssh_channel *b = (struct ssh_channel *)bv;
304 if (*a < b->localid) return -1;
305 if (*a > b->localid) return +1;
306 return 0;
307 }
308
309 static void c_write (char *buf, int len) {
310 if ((flags & FLAG_STDERR)) {
311 int i;
312 for (i = 0; i < len; i++)
313 if (buf[i] != '\r')
314 fputc(buf[i], stderr);
315 return;
316 }
317 from_backend(1, buf, len);
318 }
319
320 /*
321 * Collect incoming data in the incoming packet buffer.
322 * Decipher and verify the packet when it is completely read.
323 * Drop SSH1_MSG_DEBUG and SSH1_MSG_IGNORE packets.
324 * Update the *data and *datalen variables.
325 * Return the additional nr of bytes needed, or 0 when
326 * a complete packet is available.
327 */
328 static int ssh1_rdpkt(unsigned char **data, int *datalen)
329 {
330 struct rdpkt1_state_tag *st = &rdpkt1_state;
331
332 crBegin;
333
334 next_packet:
335
336 pktin.type = 0;
337 pktin.length = 0;
338
339 for (st->i = st->len = 0; st->i < 4; st->i++) {
340 while ((*datalen) == 0)
341 crReturn(4-st->i);
342 st->len = (st->len << 8) + **data;
343 (*data)++, (*datalen)--;
344 }
345
346 #ifdef FWHACK
347 if (st->len == 0x52656d6f) { /* "Remo"te server has closed ... */
348 st->len = 0x300; /* big enough to carry to end */
349 }
350 #endif
351
352 st->pad = 8 - (st->len % 8);
353 st->biglen = st->len + st->pad;
354 pktin.length = st->len - 5;
355
356 if (pktin.maxlen < st->biglen) {
357 pktin.maxlen = st->biglen;
358 pktin.data = (pktin.data == NULL ? malloc(st->biglen+APIEXTRA) :
359 realloc(pktin.data, st->biglen+APIEXTRA));
360 if (!pktin.data)
361 fatalbox("Out of memory");
362 }
363
364 st->to_read = st->biglen;
365 st->p = pktin.data;
366 while (st->to_read > 0) {
367 st->chunk = st->to_read;
368 while ((*datalen) == 0)
369 crReturn(st->to_read);
370 if (st->chunk > (*datalen))
371 st->chunk = (*datalen);
372 memcpy(st->p, *data, st->chunk);
373 *data += st->chunk;
374 *datalen -= st->chunk;
375 st->p += st->chunk;
376 st->to_read -= st->chunk;
377 }
378
379 if (cipher)
380 cipher->decrypt(pktin.data, st->biglen);
381 #if 0
382 debug(("Got packet len=%d pad=%d\r\n", st->len, st->pad));
383 for (st->i = 0; st->i < st->biglen; st->i++)
384 debug((" %02x", (unsigned char)pktin.data[st->i]));
385 debug(("\r\n"));
386 #endif
387
388 st->realcrc = crc32(pktin.data, st->biglen-4);
389 st->gotcrc = GET_32BIT(pktin.data+st->biglen-4);
390 if (st->gotcrc != st->realcrc) {
391 bombout(("Incorrect CRC received on packet"));
392 crReturn(0);
393 }
394
395 pktin.body = pktin.data + st->pad + 1;
396
397 if (ssh1_compressing) {
398 unsigned char *decompblk;
399 int decomplen;
400 #if 0
401 int i;
402 debug(("Packet payload pre-decompression:\n"));
403 for (i = -1; i < pktin.length; i++)
404 debug((" %02x", (unsigned char)pktin.body[i]));
405 debug(("\r\n"));
406 #endif
407 zlib_decompress_block(pktin.body-1, pktin.length+1,
408 &decompblk, &decomplen);
409
410 if (pktin.maxlen < st->pad + decomplen) {
411 pktin.maxlen = st->pad + decomplen;
412 pktin.data = realloc(pktin.data, pktin.maxlen+APIEXTRA);
413 if (!pktin.data)
414 fatalbox("Out of memory");
415 }
416
417 memcpy(pktin.body-1, decompblk, decomplen);
418 free(decompblk);
419 pktin.length = decomplen-1;
420 #if 0
421 debug(("Packet payload post-decompression:\n"));
422 for (i = -1; i < pktin.length; i++)
423 debug((" %02x", (unsigned char)pktin.body[i]));
424 debug(("\r\n"));
425 #endif
426 }
427
428 if (pktin.type == SSH1_SMSG_STDOUT_DATA ||
429 pktin.type == SSH1_SMSG_STDERR_DATA ||
430 pktin.type == SSH1_MSG_DEBUG ||
431 pktin.type == SSH1_SMSG_AUTH_TIS_CHALLENGE ||
432 pktin.type == SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
433 long strlen = GET_32BIT(pktin.body);
434 if (strlen + 4 != pktin.length) {
435 bombout(("Received data packet with bogus string length"));
436 crReturn(0);
437 }
438 }
439
440 pktin.type = pktin.body[-1];
441
442 if (pktin.type == SSH1_MSG_DEBUG) {
443 /* log debug message */
444 char buf[80];
445 int strlen = GET_32BIT(pktin.body);
446 strcpy(buf, "Remote: ");
447 if (strlen > 70) strlen = 70;
448 memcpy(buf+8, pktin.body+4, strlen);
449 buf[8+strlen] = '\0';
450 logevent(buf);
451 goto next_packet;
452 } else if (pktin.type == SSH1_MSG_IGNORE) {
453 /* do nothing */
454 goto next_packet;
455 }
456
457 crFinish(0);
458 }
459
460 static int ssh2_rdpkt(unsigned char **data, int *datalen)
461 {
462 struct rdpkt2_state_tag *st = &rdpkt2_state;
463
464 crBegin;
465
466 next_packet:
467 pktin.type = 0;
468 pktin.length = 0;
469 if (sccipher)
470 st->cipherblk = sccipher->blksize;
471 else
472 st->cipherblk = 8;
473 if (st->cipherblk < 8)
474 st->cipherblk = 8;
475
476 if (pktin.maxlen < st->cipherblk) {
477 pktin.maxlen = st->cipherblk;
478 pktin.data = (pktin.data == NULL ? malloc(st->cipherblk+APIEXTRA) :
479 realloc(pktin.data, st->cipherblk+APIEXTRA));
480 if (!pktin.data)
481 fatalbox("Out of memory");
482 }
483
484 /*
485 * Acquire and decrypt the first block of the packet. This will
486 * contain the length and padding details.
487 */
488 for (st->i = st->len = 0; st->i < st->cipherblk; st->i++) {
489 while ((*datalen) == 0)
490 crReturn(st->cipherblk-st->i);
491 pktin.data[st->i] = *(*data)++;
492 (*datalen)--;
493 }
494 #ifdef FWHACK
495 if (!memcmp(pktin.data, "Remo", 4)) {/* "Remo"te server has closed ... */
496 /* FIXME */
497 }
498 #endif
499 if (sccipher)
500 sccipher->decrypt(pktin.data, st->cipherblk);
501
502 /*
503 * Now get the length and padding figures.
504 */
505 st->len = GET_32BIT(pktin.data);
506 st->pad = pktin.data[4];
507
508 /*
509 * This enables us to deduce the payload length.
510 */
511 st->payload = st->len - st->pad - 1;
512
513 pktin.length = st->payload + 5;
514
515 /*
516 * So now we can work out the total packet length.
517 */
518 st->packetlen = st->len + 4;
519 st->maclen = scmac ? scmac->len : 0;
520
521 /*
522 * Adjust memory allocation if packet is too big.
523 */
524 if (pktin.maxlen < st->packetlen+st->maclen) {
525 pktin.maxlen = st->packetlen+st->maclen;
526 pktin.data = (pktin.data == NULL ? malloc(pktin.maxlen+APIEXTRA) :
527 realloc(pktin.data, pktin.maxlen+APIEXTRA));
528 if (!pktin.data)
529 fatalbox("Out of memory");
530 }
531
532 /*
533 * Read and decrypt the remainder of the packet.
534 */
535 for (st->i = st->cipherblk; st->i < st->packetlen + st->maclen; st->i++) {
536 while ((*datalen) == 0)
537 crReturn(st->packetlen + st->maclen - st->i);
538 pktin.data[st->i] = *(*data)++;
539 (*datalen)--;
540 }
541 /* Decrypt everything _except_ the MAC. */
542 if (sccipher)
543 sccipher->decrypt(pktin.data + st->cipherblk,
544 st->packetlen - st->cipherblk);
545
546 #if 0
547 debug(("Got packet len=%d pad=%d\r\n", st->len, st->pad));
548 for (st->i = 0; st->i < st->packetlen; st->i++)
549 debug((" %02x", (unsigned char)pktin.data[st->i]));
550 debug(("\r\n"));
551 #endif
552
553 /*
554 * Check the MAC.
555 */
556 if (scmac && !scmac->verify(pktin.data, st->len+4, st->incoming_sequence)) {
557 bombout(("Incorrect MAC received on packet"));
558 crReturn(0);
559 }
560 st->incoming_sequence++; /* whether or not we MACed */
561
562 /*
563 * Decompress packet payload.
564 */
565 {
566 unsigned char *newpayload;
567 int newlen;
568 if (sccomp && sccomp->decompress(pktin.data+5, pktin.length-5,
569 &newpayload, &newlen)) {
570 if (pktin.maxlen < newlen+5) {
571 pktin.maxlen = newlen+5;
572 pktin.data = (pktin.data == NULL ? malloc(pktin.maxlen+APIEXTRA) :
573 realloc(pktin.data, pktin.maxlen+APIEXTRA));
574 if (!pktin.data)
575 fatalbox("Out of memory");
576 }
577 pktin.length = 5 + newlen;
578 memcpy(pktin.data+5, newpayload, newlen);
579 #if 0
580 debug(("Post-decompression payload:\r\n"));
581 for (st->i = 0; st->i < newlen; st->i++)
582 debug((" %02x", (unsigned char)pktin.data[5+st->i]));
583 debug(("\r\n"));
584 #endif
585
586 free(newpayload);
587 }
588 }
589
590 pktin.savedpos = 6;
591 pktin.type = pktin.data[5];
592
593 if (pktin.type == SSH2_MSG_IGNORE || pktin.type == SSH2_MSG_DEBUG)
594 goto next_packet; /* FIXME: print DEBUG message */
595
596 crFinish(0);
597 }
598
599 static void ssh1_pktout_size(int len) {
600 int pad, biglen;
601
602 len += 5; /* type and CRC */
603 pad = 8 - (len%8);
604 biglen = len + pad;
605
606 pktout.length = len-5;
607 if (pktout.maxlen < biglen) {
608 pktout.maxlen = biglen;
609 #ifdef MSCRYPTOAPI
610 /* Allocate enough buffer space for extra block
611 * for MS CryptEncrypt() */
612 pktout.data = (pktout.data == NULL ? malloc(biglen+12) :
613 realloc(pktout.data, biglen+12));
614 #else
615 pktout.data = (pktout.data == NULL ? malloc(biglen+4) :
616 realloc(pktout.data, biglen+4));
617 #endif
618 if (!pktout.data)
619 fatalbox("Out of memory");
620 }
621 pktout.body = pktout.data+4+pad+1;
622 }
623
624 static void s_wrpkt_start(int type, int len) {
625 ssh1_pktout_size(len);
626 pktout.type = type;
627 }
628
629 static void s_wrpkt(void) {
630 int pad, len, biglen, i;
631 unsigned long crc;
632
633 pktout.body[-1] = pktout.type;
634
635 if (ssh1_compressing) {
636 unsigned char *compblk;
637 int complen;
638 #if 0
639 debug(("Packet payload pre-compression:\n"));
640 for (i = -1; i < pktout.length; i++)
641 debug((" %02x", (unsigned char)pktout.body[i]));
642 debug(("\r\n"));
643 #endif
644 zlib_compress_block(pktout.body-1, pktout.length+1,
645 &compblk, &complen);
646 ssh1_pktout_size(complen-1);
647 memcpy(pktout.body-1, compblk, complen);
648 free(compblk);
649 #if 0
650 debug(("Packet payload post-compression:\n"));
651 for (i = -1; i < pktout.length; i++)
652 debug((" %02x", (unsigned char)pktout.body[i]));
653 debug(("\r\n"));
654 #endif
655 }
656
657 len = pktout.length + 5; /* type and CRC */
658 pad = 8 - (len%8);
659 biglen = len + pad;
660
661 for (i=0; i<pad; i++)
662 pktout.data[i+4] = random_byte();
663 crc = crc32(pktout.data+4, biglen-4);
664 PUT_32BIT(pktout.data+biglen, crc);
665 PUT_32BIT(pktout.data, len);
666
667 #if 0
668 debug(("Sending packet len=%d\r\n", biglen+4));
669 for (i = 0; i < biglen+4; i++)
670 debug((" %02x", (unsigned char)pktout.data[i]));
671 debug(("\r\n"));
672 #endif
673 if (cipher)
674 cipher->encrypt(pktout.data+4, biglen);
675
676 sk_write(s, pktout.data, biglen+4);
677 }
678
679 /*
680 * Construct a packet with the specified contents and
681 * send it to the server.
682 */
683 static void send_packet(int pkttype, ...)
684 {
685 va_list args;
686 unsigned char *p, *argp, argchar;
687 unsigned long argint;
688 int pktlen, argtype, arglen;
689 Bignum bn;
690
691 pktlen = 0;
692 va_start(args, pkttype);
693 while ((argtype = va_arg(args, int)) != PKT_END) {
694 switch (argtype) {
695 case PKT_INT:
696 (void) va_arg(args, int);
697 pktlen += 4;
698 break;
699 case PKT_CHAR:
700 (void) va_arg(args, char);
701 pktlen++;
702 break;
703 case PKT_DATA:
704 (void) va_arg(args, unsigned char *);
705 arglen = va_arg(args, int);
706 pktlen += arglen;
707 break;
708 case PKT_STR:
709 argp = va_arg(args, unsigned char *);
710 arglen = strlen(argp);
711 pktlen += 4 + arglen;
712 break;
713 case PKT_BIGNUM:
714 bn = va_arg(args, Bignum);
715 pktlen += ssh1_bignum_length(bn);
716 break;
717 default:
718 assert(0);
719 }
720 }
721 va_end(args);
722
723 s_wrpkt_start(pkttype, pktlen);
724 p = pktout.body;
725
726 va_start(args, pkttype);
727 while ((argtype = va_arg(args, int)) != PKT_END) {
728 switch (argtype) {
729 case PKT_INT:
730 argint = va_arg(args, int);
731 PUT_32BIT(p, argint);
732 p += 4;
733 break;
734 case PKT_CHAR:
735 argchar = va_arg(args, unsigned char);
736 *p = argchar;
737 p++;
738 break;
739 case PKT_DATA:
740 argp = va_arg(args, unsigned char *);
741 arglen = va_arg(args, int);
742 memcpy(p, argp, arglen);
743 p += arglen;
744 break;
745 case PKT_STR:
746 argp = va_arg(args, unsigned char *);
747 arglen = strlen(argp);
748 PUT_32BIT(p, arglen);
749 memcpy(p + 4, argp, arglen);
750 p += 4 + arglen;
751 break;
752 case PKT_BIGNUM:
753 bn = va_arg(args, Bignum);
754 p += ssh1_write_bignum(p, bn);
755 break;
756 }
757 }
758 va_end(args);
759
760 s_wrpkt();
761 }
762
763 static int ssh_versioncmp(char *a, char *b) {
764 char *ae, *be;
765 unsigned long av, bv;
766
767 av = strtoul(a, &ae, 10);
768 bv = strtoul(b, &be, 10);
769 if (av != bv) return (av < bv ? -1 : +1);
770 if (*ae == '.') ae++;
771 if (*be == '.') be++;
772 av = strtoul(ae, &ae, 10);
773 bv = strtoul(be, &be, 10);
774 if (av != bv) return (av < bv ? -1 : +1);
775 return 0;
776 }
777
778
779 /*
780 * Utility routine for putting an SSH-protocol `string' into a SHA
781 * state.
782 */
783 #include <stdio.h>
784 static void sha_string(SHA_State *s, void *str, int len) {
785 unsigned char lenblk[4];
786 PUT_32BIT(lenblk, len);
787 SHA_Bytes(s, lenblk, 4);
788 SHA_Bytes(s, str, len);
789 }
790
791 /*
792 * SSH2 packet construction functions.
793 */
794 static void ssh2_pkt_adddata(void *data, int len) {
795 pktout.length += len;
796 if (pktout.maxlen < pktout.length) {
797 pktout.maxlen = pktout.length + 256;
798 pktout.data = (pktout.data == NULL ? malloc(pktout.maxlen+APIEXTRA) :
799 realloc(pktout.data, pktout.maxlen+APIEXTRA));
800 if (!pktout.data)
801 fatalbox("Out of memory");
802 }
803 memcpy(pktout.data+pktout.length-len, data, len);
804 }
805 static void ssh2_pkt_addbyte(unsigned char byte) {
806 ssh2_pkt_adddata(&byte, 1);
807 }
808 static void ssh2_pkt_init(int pkt_type) {
809 pktout.length = 5;
810 ssh2_pkt_addbyte((unsigned char)pkt_type);
811 }
812 static void ssh2_pkt_addbool(unsigned char value) {
813 ssh2_pkt_adddata(&value, 1);
814 }
815 static void ssh2_pkt_adduint32(unsigned long value) {
816 unsigned char x[4];
817 PUT_32BIT(x, value);
818 ssh2_pkt_adddata(x, 4);
819 }
820 static void ssh2_pkt_addstring_start(void) {
821 ssh2_pkt_adduint32(0);
822 pktout.savedpos = pktout.length;
823 }
824 static void ssh2_pkt_addstring_str(char *data) {
825 ssh2_pkt_adddata(data, strlen(data));
826 PUT_32BIT(pktout.data + pktout.savedpos - 4,
827 pktout.length - pktout.savedpos);
828 }
829 static void ssh2_pkt_addstring_data(char *data, int len) {
830 ssh2_pkt_adddata(data, len);
831 PUT_32BIT(pktout.data + pktout.savedpos - 4,
832 pktout.length - pktout.savedpos);
833 }
834 static void ssh2_pkt_addstring(char *data) {
835 ssh2_pkt_addstring_start();
836 ssh2_pkt_addstring_str(data);
837 }
838 static char *ssh2_mpint_fmt(Bignum b, int *len) {
839 unsigned char *p;
840 int i, n = b[0];
841 p = malloc(n * 2 + 1);
842 if (!p)
843 fatalbox("out of memory");
844 p[0] = 0;
845 for (i = 0; i < n; i++) {
846 p[i*2+1] = (b[n-i] >> 8) & 0xFF;
847 p[i*2+2] = (b[n-i] ) & 0xFF;
848 }
849 i = 0;
850 while (p[i] == 0 && (p[i+1] & 0x80) == 0)
851 i++;
852 memmove(p, p+i, n*2+1-i);
853 *len = n*2+1-i;
854 return p;
855 }
856 static void ssh2_pkt_addmp(Bignum b) {
857 unsigned char *p;
858 int len;
859 p = ssh2_mpint_fmt(b, &len);
860 ssh2_pkt_addstring_start();
861 ssh2_pkt_addstring_data(p, len);
862 free(p);
863 }
864 static void ssh2_pkt_send(void) {
865 int cipherblk, maclen, padding, i;
866 static unsigned long outgoing_sequence = 0;
867
868 /*
869 * Compress packet payload.
870 */
871 #if 0
872 debug(("Pre-compression payload:\r\n"));
873 for (i = 5; i < pktout.length; i++)
874 debug((" %02x", (unsigned char)pktout.data[i]));
875 debug(("\r\n"));
876 #endif
877 {
878 unsigned char *newpayload;
879 int newlen;
880 if (cscomp && cscomp->compress(pktout.data+5, pktout.length-5,
881 &newpayload, &newlen)) {
882 pktout.length = 5;
883 ssh2_pkt_adddata(newpayload, newlen);
884 free(newpayload);
885 }
886 }
887
888 /*
889 * Add padding. At least four bytes, and must also bring total
890 * length (minus MAC) up to a multiple of the block size.
891 */
892 cipherblk = cipher ? cipher->blksize : 8; /* block size */
893 cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */
894 padding = 4;
895 padding += (cipherblk - (pktout.length + padding) % cipherblk) % cipherblk;
896 pktout.data[4] = padding;
897 for (i = 0; i < padding; i++)
898 pktout.data[pktout.length + i] = random_byte();
899 PUT_32BIT(pktout.data, pktout.length + padding - 4);
900 if (csmac)
901 csmac->generate(pktout.data, pktout.length + padding,
902 outgoing_sequence);
903 outgoing_sequence++; /* whether or not we MACed */
904
905 #if 0
906 debug(("Sending packet len=%d\r\n", pktout.length+padding));
907 for (i = 0; i < pktout.length+padding; i++)
908 debug((" %02x", (unsigned char)pktout.data[i]));
909 debug(("\r\n"));
910 #endif
911
912 if (cscipher)
913 cscipher->encrypt(pktout.data, pktout.length + padding);
914 maclen = csmac ? csmac->len : 0;
915
916 sk_write(s, pktout.data, pktout.length + padding + maclen);
917 }
918
919 #if 0
920 void bndebug(char *string, Bignum b) {
921 unsigned char *p;
922 int i, len;
923 p = ssh2_mpint_fmt(b, &len);
924 debug(("%s", string));
925 for (i = 0; i < len; i++)
926 debug((" %02x", p[i]));
927 debug(("\r\n"));
928 free(p);
929 }
930 #endif
931
932 static void sha_mpint(SHA_State *s, Bignum b) {
933 unsigned char *p;
934 int len;
935 p = ssh2_mpint_fmt(b, &len);
936 sha_string(s, p, len);
937 free(p);
938 }
939
940 /*
941 * SSH2 packet decode functions.
942 */
943 static unsigned long ssh2_pkt_getuint32(void) {
944 unsigned long value;
945 if (pktin.length - pktin.savedpos < 4)
946 return 0; /* arrgh, no way to decline (FIXME?) */
947 value = GET_32BIT(pktin.data+pktin.savedpos);
948 pktin.savedpos += 4;
949 return value;
950 }
951 static void ssh2_pkt_getstring(char **p, int *length) {
952 *p = NULL;
953 if (pktin.length - pktin.savedpos < 4)
954 return;
955 *length = GET_32BIT(pktin.data+pktin.savedpos);
956 pktin.savedpos += 4;
957 if (pktin.length - pktin.savedpos < *length)
958 return;
959 *p = pktin.data+pktin.savedpos;
960 pktin.savedpos += *length;
961 }
962 static Bignum ssh2_pkt_getmp(void) {
963 char *p;
964 int i, j, length;
965 Bignum b;
966
967 ssh2_pkt_getstring(&p, &length);
968 if (!p)
969 return NULL;
970 if (p[0] & 0x80) {
971 bombout(("internal error: Can't handle negative mpints"));
972 return NULL;
973 }
974 b = newbn((length+1)/2);
975 for (i = 0; i < length; i++) {
976 j = length - 1 - i;
977 if (j & 1)
978 b[j/2+1] |= ((unsigned char)p[i]) << 8;
979 else
980 b[j/2+1] |= ((unsigned char)p[i]);
981 }
982 while (b[0] > 1 && b[b[0]] == 0) b[0]--;
983 return b;
984 }
985
986 static int do_ssh_init(unsigned char c) {
987 static char *vsp;
988 static char version[10];
989 static char vstring[80];
990 static char vlog[sizeof(vstring)+20];
991 static int i;
992
993 crBegin;
994
995 /* Search for the string "SSH-" in the input. */
996 i = 0;
997 while (1) {
998 static const int transS[] = { 1, 2, 2, 1 };
999 static const int transH[] = { 0, 0, 3, 0 };
1000 static const int transminus[] = { 0, 0, 0, -1 };
1001 if (c == 'S') i = transS[i];
1002 else if (c == 'H') i = transH[i];
1003 else if (c == '-') i = transminus[i];
1004 else i = 0;
1005 if (i < 0)
1006 break;
1007 crReturn(1); /* get another character */
1008 }
1009
1010 strcpy(vstring, "SSH-");
1011 vsp = vstring+4;
1012 i = 0;
1013 while (1) {
1014 crReturn(1); /* get another char */
1015 if (vsp < vstring+sizeof(vstring)-1)
1016 *vsp++ = c;
1017 if (i >= 0) {
1018 if (c == '-') {
1019 version[i] = '\0';
1020 i = -1;
1021 } else if (i < sizeof(version)-1)
1022 version[i++] = c;
1023 }
1024 else if (c == '\n')
1025 break;
1026 }
1027
1028 ssh_agentfwd_enabled = FALSE;
1029 rdpkt2_state.incoming_sequence = 0;
1030
1031 *vsp = 0;
1032 sprintf(vlog, "Server version: %s", vstring);
1033 vlog[strcspn(vlog, "\r\n")] = '\0';
1034 logevent(vlog);
1035
1036 /*
1037 * Server version "1.99" means we can choose whether we use v1
1038 * or v2 protocol. Choice is based on cfg.sshprot.
1039 */
1040 if (ssh_versioncmp(version, cfg.sshprot == 1 ? "2.0" : "1.99") >= 0) {
1041 /*
1042 * This is a v2 server. Begin v2 protocol.
1043 */
1044 char *verstring = "SSH-2.0-PuTTY";
1045 SHA_Init(&exhash);
1046 /*
1047 * Hash our version string and their version string.
1048 */
1049 sha_string(&exhash, verstring, strlen(verstring));
1050 sha_string(&exhash, vstring, strcspn(vstring, "\r\n"));
1051 sprintf(vstring, "%s\n", verstring);
1052 sprintf(vlog, "We claim version: %s", verstring);
1053 logevent(vlog);
1054 logevent("Using SSH protocol version 2");
1055 sk_write(s, vstring, strlen(vstring));
1056 ssh_protocol = ssh2_protocol;
1057 ssh_version = 2;
1058 s_rdpkt = ssh2_rdpkt;
1059 } else {
1060 /*
1061 * This is a v1 server. Begin v1 protocol.
1062 */
1063 sprintf(vstring, "SSH-%s-PuTTY\n",
1064 (ssh_versioncmp(version, "1.5") <= 0 ? version : "1.5"));
1065 sprintf(vlog, "We claim version: %s", vstring);
1066 vlog[strcspn(vlog, "\r\n")] = '\0';
1067 logevent(vlog);
1068 logevent("Using SSH protocol version 1");
1069 sk_write(s, vstring, strlen(vstring));
1070 ssh_protocol = ssh1_protocol;
1071 ssh_version = 1;
1072 s_rdpkt = ssh1_rdpkt;
1073 }
1074
1075 crFinish(0);
1076 }
1077
1078 static void ssh_gotdata(unsigned char *data, int datalen)
1079 {
1080 crBegin;
1081
1082 /*
1083 * To begin with, feed the characters one by one to the
1084 * protocol initialisation / selection function do_ssh_init().
1085 * When that returns 0, we're done with the initial greeting
1086 * exchange and can move on to packet discipline.
1087 */
1088 while (1) {
1089 int ret;
1090 if (datalen == 0)
1091 crReturnV; /* more data please */
1092 ret = do_ssh_init(*data);
1093 data++; datalen--;
1094 if (ret == 0)
1095 break;
1096 }
1097
1098 /*
1099 * We emerge from that loop when the initial negotiation is
1100 * over and we have selected an s_rdpkt function. Now pass
1101 * everything to s_rdpkt, and then pass the resulting packets
1102 * to the proper protocol handler.
1103 */
1104 if (datalen == 0)
1105 crReturnV;
1106 while (1) {
1107 while (datalen > 0) {
1108 if ( s_rdpkt(&data, &datalen) == 0 ) {
1109 ssh_protocol(NULL, 0, 1);
1110 if (ssh_state == SSH_STATE_CLOSED) {
1111 return;
1112 }
1113 }
1114 }
1115 crReturnV;
1116 }
1117 crFinishV;
1118 }
1119
1120 static int ssh_receive(Socket skt, int urgent, char *data, int len) {
1121 if (!len) {
1122 /* Connection has closed. */
1123 sk_close(s);
1124 s = NULL;
1125 return 0;
1126 }
1127 ssh_gotdata (data, len);
1128 if (ssh_state == SSH_STATE_CLOSED) {
1129 if (s) {
1130 sk_close(s);
1131 s = NULL;
1132 }
1133 return 0;
1134 }
1135 return 1;
1136 }
1137
1138 /*
1139 * Connect to specified host and port.
1140 * Returns an error message, or NULL on success.
1141 * Also places the canonical host name into `realhost'.
1142 */
1143 static char *connect_to_host(char *host, int port, char **realhost)
1144 {
1145 SockAddr addr;
1146 char *err;
1147 #ifdef FWHACK
1148 char *FWhost;
1149 int FWport;
1150 #endif
1151
1152 savedhost = malloc(1+strlen(host));
1153 if (!savedhost)
1154 fatalbox("Out of memory");
1155 strcpy(savedhost, host);
1156
1157 if (port < 0)
1158 port = 22; /* default ssh port */
1159 savedport = port;
1160
1161 #ifdef FWHACK
1162 FWhost = host;
1163 FWport = port;
1164 host = FWSTR;
1165 port = 23;
1166 #endif
1167
1168 /*
1169 * Try to find host.
1170 */
1171 addr = sk_namelookup(host, realhost);
1172 if ( (err = sk_addr_error(addr)) )
1173 return err;
1174
1175 #ifdef FWHACK
1176 *realhost = FWhost;
1177 #endif
1178
1179 /*
1180 * Open socket.
1181 */
1182 s = sk_new(addr, port, ssh_receive);
1183 if ( (err = sk_socket_error(s)) )
1184 return err;
1185
1186 #ifdef FWHACK
1187 sk_write(s, "connect ", 8);
1188 sk_write(s, FWhost, strlen(FWhost));
1189 {
1190 char buf[20];
1191 sprintf(buf, " %d\n", FWport);
1192 sk_write(s, buf, strlen(buf));
1193 }
1194 #endif
1195
1196 return NULL;
1197 }
1198
1199 /*
1200 * Handle the key exchange and user authentication phases.
1201 */
1202 static int do_ssh1_login(unsigned char *in, int inlen, int ispkt)
1203 {
1204 int i, j, len;
1205 unsigned char *rsabuf, *keystr1, *keystr2;
1206 unsigned char cookie[8];
1207 struct RSAKey servkey, hostkey;
1208 struct MD5Context md5c;
1209 static unsigned long supported_ciphers_mask, supported_auths_mask;
1210 static int tried_publickey;
1211 static unsigned char session_id[16];
1212 int cipher_type;
1213 static char username[100];
1214
1215 crBegin;
1216
1217 if (!ispkt) crWaitUntil(ispkt);
1218
1219 if (pktin.type != SSH1_SMSG_PUBLIC_KEY) {
1220 bombout(("Public key packet not received"));
1221 crReturn(0);
1222 }
1223
1224 logevent("Received public keys");
1225
1226 memcpy(cookie, pktin.body, 8);
1227
1228 i = makekey(pktin.body+8, &servkey, &keystr1, 0);
1229 j = makekey(pktin.body+8+i, &hostkey, &keystr2, 0);
1230
1231 /*
1232 * Log the host key fingerprint.
1233 */
1234 {
1235 char logmsg[80];
1236 logevent("Host key fingerprint is:");
1237 strcpy(logmsg, " ");
1238 hostkey.comment = NULL;
1239 rsa_fingerprint(logmsg+strlen(logmsg), sizeof(logmsg)-strlen(logmsg),
1240 &hostkey);
1241 logevent(logmsg);
1242 }
1243
1244 supported_ciphers_mask = GET_32BIT(pktin.body+12+i+j);
1245 supported_auths_mask = GET_32BIT(pktin.body+16+i+j);
1246
1247 MD5Init(&md5c);
1248 MD5Update(&md5c, keystr2, hostkey.bytes);
1249 MD5Update(&md5c, keystr1, servkey.bytes);
1250 MD5Update(&md5c, pktin.body, 8);
1251 MD5Final(session_id, &md5c);
1252
1253 for (i=0; i<32; i++)
1254 session_key[i] = random_byte();
1255
1256 len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes);
1257
1258 rsabuf = malloc(len);
1259 if (!rsabuf)
1260 fatalbox("Out of memory");
1261
1262 /*
1263 * Verify the host key.
1264 */
1265 {
1266 /*
1267 * First format the key into a string.
1268 */
1269 int len = rsastr_len(&hostkey);
1270 char fingerprint[100];
1271 char *keystr = malloc(len);
1272 if (!keystr)
1273 fatalbox("Out of memory");
1274 rsastr_fmt(keystr, &hostkey);
1275 rsa_fingerprint(fingerprint, sizeof(fingerprint), &hostkey);
1276 verify_ssh_host_key(savedhost, savedport, "rsa", keystr, fingerprint);
1277 free(keystr);
1278 }
1279
1280 for (i=0; i<32; i++) {
1281 rsabuf[i] = session_key[i];
1282 if (i < 16)
1283 rsabuf[i] ^= session_id[i];
1284 }
1285
1286 if (hostkey.bytes > servkey.bytes) {
1287 rsaencrypt(rsabuf, 32, &servkey);
1288 rsaencrypt(rsabuf, servkey.bytes, &hostkey);
1289 } else {
1290 rsaencrypt(rsabuf, 32, &hostkey);
1291 rsaencrypt(rsabuf, hostkey.bytes, &servkey);
1292 }
1293
1294 logevent("Encrypted session key");
1295
1296 cipher_type = cfg.cipher == CIPHER_BLOWFISH ? SSH_CIPHER_BLOWFISH :
1297 cfg.cipher == CIPHER_DES ? SSH_CIPHER_DES :
1298 SSH_CIPHER_3DES;
1299 if ((supported_ciphers_mask & (1 << cipher_type)) == 0) {
1300 c_write("Selected cipher not supported, falling back to 3DES\r\n", 53);
1301 cipher_type = SSH_CIPHER_3DES;
1302 }
1303 switch (cipher_type) {
1304 case SSH_CIPHER_3DES: logevent("Using 3DES encryption"); break;
1305 case SSH_CIPHER_DES: logevent("Using single-DES encryption"); break;
1306 case SSH_CIPHER_BLOWFISH: logevent("Using Blowfish encryption"); break;
1307 }
1308
1309 send_packet(SSH1_CMSG_SESSION_KEY,
1310 PKT_CHAR, cipher_type,
1311 PKT_DATA, cookie, 8,
1312 PKT_CHAR, (len*8) >> 8, PKT_CHAR, (len*8) & 0xFF,
1313 PKT_DATA, rsabuf, len,
1314 PKT_INT, 0,
1315 PKT_END);
1316
1317 logevent("Trying to enable encryption...");
1318
1319 free(rsabuf);
1320
1321 cipher = cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 :
1322 cipher_type == SSH_CIPHER_DES ? &ssh_des :
1323 &ssh_3des;
1324 cipher->sesskey(session_key);
1325
1326 crWaitUntil(ispkt);
1327
1328 if (pktin.type != SSH1_SMSG_SUCCESS) {
1329 bombout(("Encryption not successfully enabled"));
1330 crReturn(0);
1331 }
1332
1333 logevent("Successfully started encryption");
1334
1335 fflush(stdout);
1336 {
1337 static int pos = 0;
1338 static char c;
1339 if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
1340 c_write("login as: ", 10);
1341 ssh_send_ok = 1;
1342 while (pos >= 0) {
1343 crWaitUntil(!ispkt);
1344 while (inlen--) switch (c = *in++) {
1345 case 10: case 13:
1346 username[pos] = 0;
1347 pos = -1;
1348 break;
1349 case 8: case 127:
1350 if (pos > 0) {
1351 c_write("\b \b", 3);
1352 pos--;
1353 }
1354 break;
1355 case 21: case 27:
1356 while (pos > 0) {
1357 c_write("\b \b", 3);
1358 pos--;
1359 }
1360 break;
1361 case 3: case 4:
1362 random_save_seed();
1363 exit(0);
1364 break;
1365 default:
1366 if (((c >= ' ' && c <= '~') ||
1367 ((unsigned char)c >= 160)) && pos < 40) {
1368 username[pos++] = c;
1369 c_write(&c, 1);
1370 }
1371 break;
1372 }
1373 }
1374 c_write("\r\n", 2);
1375 username[strcspn(username, "\n\r")] = '\0';
1376 } else {
1377 strncpy(username, cfg.username, 99);
1378 username[99] = '\0';
1379 }
1380
1381 send_packet(SSH1_CMSG_USER, PKT_STR, username, PKT_END);
1382 {
1383 char userlog[22+sizeof(username)];
1384 sprintf(userlog, "Sent username \"%s\"", username);
1385 logevent(userlog);
1386 if (flags & FLAG_INTERACTIVE &&
1387 (!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) {
1388 strcat(userlog, "\r\n");
1389 c_write(userlog, strlen(userlog));
1390 }
1391 }
1392 }
1393
1394 crWaitUntil(ispkt);
1395
1396 tried_publickey = 0;
1397
1398 while (pktin.type == SSH1_SMSG_FAILURE) {
1399 static char password[100];
1400 static char prompt[200];
1401 static int pos;
1402 static char c;
1403 static int pwpkt_type;
1404 /*
1405 * Show password prompt, having first obtained it via a TIS
1406 * or CryptoCard exchange if we're doing TIS or CryptoCard
1407 * authentication.
1408 */
1409 pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
1410 if (agent_exists()) {
1411 /*
1412 * Attempt RSA authentication using Pageant.
1413 */
1414 static unsigned char request[5], *response, *p;
1415 static int responselen;
1416 static int i, nkeys;
1417 static int authed = FALSE;
1418 void *r;
1419
1420 logevent("Pageant is running. Requesting keys.");
1421
1422 /* Request the keys held by the agent. */
1423 PUT_32BIT(request, 1);
1424 request[4] = SSH_AGENTC_REQUEST_RSA_IDENTITIES;
1425 agent_query(request, 5, &r, &responselen);
1426 response = (unsigned char *)r;
1427 if (response) {
1428 p = response + 5;
1429 nkeys = GET_32BIT(p); p += 4;
1430 { char buf[64]; sprintf(buf, "Pageant has %d keys", nkeys);
1431 logevent(buf); }
1432 for (i = 0; i < nkeys; i++) {
1433 static struct RSAKey key;
1434 static Bignum challenge;
1435 static char *commentp;
1436 static int commentlen;
1437
1438 { char buf[64]; sprintf(buf, "Trying Pageant key #%d", i);
1439 logevent(buf); }
1440 p += 4;
1441 p += ssh1_read_bignum(p, &key.exponent);
1442 p += ssh1_read_bignum(p, &key.modulus);
1443 commentlen = GET_32BIT(p); p += 4;
1444 commentp = p; p += commentlen;
1445 send_packet(SSH1_CMSG_AUTH_RSA,
1446 PKT_BIGNUM, key.modulus, PKT_END);
1447 crWaitUntil(ispkt);
1448 if (pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
1449 logevent("Key refused");
1450 continue;
1451 }
1452 logevent("Received RSA challenge");
1453 ssh1_read_bignum(pktin.body, &challenge);
1454 {
1455 char *agentreq, *q, *ret;
1456 int len, retlen;
1457 len = 1 + 4; /* message type, bit count */
1458 len += ssh1_bignum_length(key.exponent);
1459 len += ssh1_bignum_length(key.modulus);
1460 len += ssh1_bignum_length(challenge);
1461 len += 16; /* session id */
1462 len += 4; /* response format */
1463 agentreq = malloc(4 + len);
1464 PUT_32BIT(agentreq, len);
1465 q = agentreq + 4;
1466 *q++ = SSH_AGENTC_RSA_CHALLENGE;
1467 PUT_32BIT(q, ssh1_bignum_bitcount(key.modulus));
1468 q += 4;
1469 q += ssh1_write_bignum(q, key.exponent);
1470 q += ssh1_write_bignum(q, key.modulus);
1471 q += ssh1_write_bignum(q, challenge);
1472 memcpy(q, session_id, 16); q += 16;
1473 PUT_32BIT(q, 1); /* response format */
1474 agent_query(agentreq, len+4, &ret, &retlen);
1475 free(agentreq);
1476 if (ret) {
1477 if (ret[4] == SSH_AGENT_RSA_RESPONSE) {
1478 logevent("Sending Pageant's response");
1479 send_packet(SSH1_CMSG_AUTH_RSA_RESPONSE,
1480 PKT_DATA, ret+5, 16, PKT_END);
1481 free(ret);
1482 crWaitUntil(ispkt);
1483 if (pktin.type == SSH1_SMSG_SUCCESS) {
1484 logevent("Pageant's response accepted");
1485 if (flags & FLAG_VERBOSE) {
1486 c_write("Authenticated using RSA key \"",
1487 29);
1488 c_write(commentp, commentlen);
1489 c_write("\" from agent\r\n", 14);
1490 }
1491 authed = TRUE;
1492 } else
1493 logevent("Pageant's response not accepted");
1494 } else {
1495 logevent("Pageant failed to answer challenge");
1496 free(ret);
1497 }
1498 } else {
1499 logevent("No reply received from Pageant");
1500 }
1501 }
1502 freebn(key.exponent);
1503 freebn(key.modulus);
1504 freebn(challenge);
1505 if (authed)
1506 break;
1507 }
1508 }
1509 if (authed)
1510 break;
1511 }
1512 if (*cfg.keyfile && !tried_publickey)
1513 pwpkt_type = SSH1_CMSG_AUTH_RSA;
1514
1515 if (pktin.type == SSH1_SMSG_FAILURE &&
1516 cfg.try_tis_auth &&
1517 (supported_auths_mask & (1<<SSH1_AUTH_TIS))) {
1518 pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
1519 logevent("Requested TIS authentication");
1520 send_packet(SSH1_CMSG_AUTH_TIS, PKT_END);
1521 crWaitUntil(ispkt);
1522 if (pktin.type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
1523 logevent("TIS authentication declined");
1524 if (flags & FLAG_INTERACTIVE)
1525 c_write("TIS authentication refused.\r\n", 29);
1526 } else {
1527 int challengelen = ((pktin.body[0] << 24) |
1528 (pktin.body[1] << 16) |
1529 (pktin.body[2] << 8) |
1530 (pktin.body[3]));
1531 logevent("Received TIS challenge");
1532 if (challengelen > sizeof(prompt)-1)
1533 challengelen = sizeof(prompt)-1; /* prevent overrun */
1534 memcpy(prompt, pktin.body+4, challengelen);
1535 prompt[challengelen] = '\0';
1536 }
1537 }
1538 if (pktin.type == SSH1_SMSG_FAILURE &&
1539 cfg.try_tis_auth &&
1540 (supported_auths_mask & (1<<SSH1_AUTH_CCARD))) {
1541 pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE;
1542 logevent("Requested CryptoCard authentication");
1543 send_packet(SSH1_CMSG_AUTH_CCARD, PKT_END);
1544 crWaitUntil(ispkt);
1545 if (pktin.type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
1546 logevent("CryptoCard authentication declined");
1547 c_write("CryptoCard authentication refused.\r\n", 29);
1548 } else {
1549 int challengelen = ((pktin.body[0] << 24) |
1550 (pktin.body[1] << 16) |
1551 (pktin.body[2] << 8) |
1552 (pktin.body[3]));
1553 logevent("Received CryptoCard challenge");
1554 if (challengelen > sizeof(prompt)-1)
1555 challengelen = sizeof(prompt)-1; /* prevent overrun */
1556 memcpy(prompt, pktin.body+4, challengelen);
1557 strncpy(prompt + challengelen, "\r\nResponse : ",
1558 sizeof(prompt)-challengelen);
1559 prompt[sizeof(prompt)-1] = '\0';
1560 }
1561 }
1562 if (pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
1563 sprintf(prompt, "%.90s@%.90s's password: ",
1564 username, savedhost);
1565 }
1566 if (pwpkt_type == SSH1_CMSG_AUTH_RSA) {
1567 char *comment = NULL;
1568 if (flags & FLAG_VERBOSE)
1569 c_write("Trying public key authentication.\r\n", 35);
1570 if (!rsakey_encrypted(cfg.keyfile, &comment)) {
1571 if (flags & FLAG_VERBOSE)
1572 c_write("No passphrase required.\r\n", 25);
1573 goto tryauth;
1574 }
1575 sprintf(prompt, "Passphrase for key \"%.100s\": ", comment);
1576 free(comment);
1577 }
1578
1579 if (ssh_get_password) {
1580 if (!ssh_get_password(prompt, password, sizeof(password))) {
1581 /*
1582 * get_password failed to get a password (for
1583 * example because one was supplied on the command
1584 * line which has already failed to work).
1585 * Terminate.
1586 */
1587 logevent("No more passwords to try");
1588 ssh_state = SSH_STATE_CLOSED;
1589 crReturn(1);
1590 }
1591 } else {
1592 c_write(prompt, strlen(prompt));
1593 pos = 0;
1594 ssh_send_ok = 1;
1595 while (pos >= 0) {
1596 crWaitUntil(!ispkt);
1597 while (inlen--) switch (c = *in++) {
1598 case 10: case 13:
1599 password[pos] = 0;
1600 pos = -1;
1601 break;
1602 case 8: case 127:
1603 if (pos > 0)
1604 pos--;
1605 break;
1606 case 21: case 27:
1607 pos = 0;
1608 break;
1609 case 3: case 4:
1610 random_save_seed();
1611 exit(0);
1612 break;
1613 default:
1614 if (((c >= ' ' && c <= '~') ||
1615 ((unsigned char)c >= 160)) && pos < sizeof(password))
1616 password[pos++] = c;
1617 break;
1618 }
1619 }
1620 c_write("\r\n", 2);
1621 }
1622
1623 tryauth:
1624 if (pwpkt_type == SSH1_CMSG_AUTH_RSA) {
1625 /*
1626 * Try public key authentication with the specified
1627 * key file.
1628 */
1629 static struct RSAKey pubkey;
1630 static Bignum challenge, response;
1631 static int i;
1632 static unsigned char buffer[32];
1633
1634 tried_publickey = 1;
1635 i = loadrsakey(cfg.keyfile, &pubkey, NULL, password);
1636 if (i == 0) {
1637 c_write("Couldn't load public key from ", 30);
1638 c_write(cfg.keyfile, strlen(cfg.keyfile));
1639 c_write(".\r\n", 3);
1640 continue; /* go and try password */
1641 }
1642 if (i == -1) {
1643 c_write("Wrong passphrase.\r\n", 19);
1644 tried_publickey = 0;
1645 continue; /* try again */
1646 }
1647
1648 /*
1649 * Send a public key attempt.
1650 */
1651 send_packet(SSH1_CMSG_AUTH_RSA,
1652 PKT_BIGNUM, pubkey.modulus, PKT_END);
1653
1654 crWaitUntil(ispkt);
1655 if (pktin.type == SSH1_SMSG_FAILURE) {
1656 c_write("Server refused our public key.\r\n", 32);
1657 continue; /* go and try password */
1658 }
1659 if (pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
1660 bombout(("Bizarre response to offer of public key"));
1661 crReturn(0);
1662 }
1663 ssh1_read_bignum(pktin.body, &challenge);
1664 response = rsadecrypt(challenge, &pubkey);
1665 freebn(pubkey.private_exponent); /* burn the evidence */
1666
1667 for (i = 0; i < 32; i += 2) {
1668 buffer[i] = response[16-i/2] >> 8;
1669 buffer[i+1] = response[16-i/2] & 0xFF;
1670 }
1671
1672 MD5Init(&md5c);
1673 MD5Update(&md5c, buffer, 32);
1674 MD5Update(&md5c, session_id, 16);
1675 MD5Final(buffer, &md5c);
1676
1677 send_packet(SSH1_CMSG_AUTH_RSA_RESPONSE,
1678 PKT_DATA, buffer, 16, PKT_END);
1679
1680 crWaitUntil(ispkt);
1681 if (pktin.type == SSH1_SMSG_FAILURE) {
1682 if (flags & FLAG_VERBOSE)
1683 c_write("Failed to authenticate with our public key.\r\n",
1684 45);
1685 continue; /* go and try password */
1686 } else if (pktin.type != SSH1_SMSG_SUCCESS) {
1687 bombout(("Bizarre response to RSA authentication response"));
1688 crReturn(0);
1689 }
1690
1691 break; /* we're through! */
1692 } else {
1693 send_packet(pwpkt_type, PKT_STR, password, PKT_END);
1694 }
1695 logevent("Sent password");
1696 memset(password, 0, strlen(password));
1697 crWaitUntil(ispkt);
1698 if (pktin.type == SSH1_SMSG_FAILURE) {
1699 if (flags & FLAG_VERBOSE)
1700 c_write("Access denied\r\n", 15);
1701 logevent("Authentication refused");
1702 } else if (pktin.type == SSH1_MSG_DISCONNECT) {
1703 logevent("Received disconnect request");
1704 ssh_state = SSH_STATE_CLOSED;
1705 crReturn(1);
1706 } else if (pktin.type != SSH1_SMSG_SUCCESS) {
1707 bombout(("Strange packet received, type %d", pktin.type));
1708 crReturn(0);
1709 }
1710 }
1711
1712 logevent("Authentication successful");
1713
1714 crFinish(1);
1715 }
1716
1717 static void ssh1_protocol(unsigned char *in, int inlen, int ispkt) {
1718 crBegin;
1719
1720 random_init();
1721
1722 while (!do_ssh1_login(in, inlen, ispkt)) {
1723 crReturnV;
1724 }
1725 if (ssh_state == SSH_STATE_CLOSED)
1726 crReturnV;
1727
1728 if (cfg.agentfwd && agent_exists()) {
1729 logevent("Requesting agent forwarding");
1730 send_packet(SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END);
1731 do { crReturnV; } while (!ispkt);
1732 if (pktin.type != SSH1_SMSG_SUCCESS && pktin.type != SSH1_SMSG_FAILURE) {
1733 bombout(("Protocol confusion"));
1734 crReturnV;
1735 } else if (pktin.type == SSH1_SMSG_FAILURE) {
1736 logevent("Agent forwarding refused");
1737 } else {
1738 logevent("Agent forwarding enabled");
1739 ssh_agentfwd_enabled = TRUE;
1740 }
1741 }
1742
1743 if (!cfg.nopty) {
1744 send_packet(SSH1_CMSG_REQUEST_PTY,
1745 PKT_STR, cfg.termtype,
1746 PKT_INT, rows, PKT_INT, cols,
1747 PKT_INT, 0, PKT_INT, 0,
1748 PKT_CHAR, 0,
1749 PKT_END);
1750 ssh_state = SSH_STATE_INTERMED;
1751 do { crReturnV; } while (!ispkt);
1752 if (pktin.type != SSH1_SMSG_SUCCESS && pktin.type != SSH1_SMSG_FAILURE) {
1753 bombout(("Protocol confusion"));
1754 crReturnV;
1755 } else if (pktin.type == SSH1_SMSG_FAILURE) {
1756 c_write("Server refused to allocate pty\r\n", 32);
1757 }
1758 logevent("Allocated pty");
1759 }
1760
1761 if (cfg.compression) {
1762 send_packet(SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END);
1763 do { crReturnV; } while (!ispkt);
1764 if (pktin.type != SSH1_SMSG_SUCCESS && pktin.type != SSH1_SMSG_FAILURE) {
1765 bombout(("Protocol confusion"));
1766 crReturnV;
1767 } else if (pktin.type == SSH1_SMSG_FAILURE) {
1768 c_write("Server refused to compress\r\n", 32);
1769 }
1770 logevent("Started compression");
1771 ssh1_compressing = TRUE;
1772 zlib_compress_init();
1773 zlib_decompress_init();
1774 }
1775
1776 if (*cfg.remote_cmd)
1777 send_packet(SSH1_CMSG_EXEC_CMD, PKT_STR, cfg.remote_cmd, PKT_END);
1778 else
1779 send_packet(SSH1_CMSG_EXEC_SHELL, PKT_END);
1780 logevent("Started session");
1781
1782 ssh_state = SSH_STATE_SESSION;
1783 if (size_needed)
1784 ssh_size();
1785
1786 ssh_send_ok = 1;
1787 ssh_channels = newtree234(ssh_channelcmp);
1788 begin_session();
1789 while (1) {
1790 crReturnV;
1791 if (ispkt) {
1792 if (pktin.type == SSH1_SMSG_STDOUT_DATA ||
1793 pktin.type == SSH1_SMSG_STDERR_DATA) {
1794 long len = GET_32BIT(pktin.body);
1795 from_backend(pktin.type == SSH1_SMSG_STDERR_DATA,
1796 pktin.body+4, len);
1797 } else if (pktin.type == SSH1_MSG_DISCONNECT) {
1798 ssh_state = SSH_STATE_CLOSED;
1799 logevent("Received disconnect request");
1800 crReturnV;
1801 } else if (pktin.type == SSH1_SMSG_AGENT_OPEN) {
1802 /* Remote side is trying to open a channel to talk to our
1803 * agent. Give them back a local channel number. */
1804 unsigned i;
1805 struct ssh_channel *c;
1806 enum234 e;
1807
1808 /* Refuse if agent forwarding is disabled. */
1809 if (!ssh_agentfwd_enabled) {
1810 send_packet(SSH1_MSG_CHANNEL_OPEN_FAILURE,
1811 PKT_INT, GET_32BIT(pktin.body),
1812 PKT_END);
1813 } else {
1814 i = 1;
1815 for (c = first234(ssh_channels, &e); c; c = next234(&e)) {
1816 if (c->localid > i)
1817 break; /* found a free number */
1818 i = c->localid + 1;
1819 }
1820 c = malloc(sizeof(struct ssh_channel));
1821 c->remoteid = GET_32BIT(pktin.body);
1822 c->localid = i;
1823 c->closes = 0;
1824 c->type = SSH1_SMSG_AGENT_OPEN;/* identify channel type */
1825 c->u.a.lensofar = 0;
1826 add234(ssh_channels, c);
1827 send_packet(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
1828 PKT_INT, c->remoteid, PKT_INT, c->localid,
1829 PKT_END);
1830 }
1831 } else if (pktin.type == SSH1_MSG_CHANNEL_CLOSE ||
1832 pktin.type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION) {
1833 /* Remote side closes a channel. */
1834 unsigned i = GET_32BIT(pktin.body);
1835 struct ssh_channel *c;
1836 c = find234(ssh_channels, &i, ssh_channelfind);
1837 if (c) {
1838 int closetype;
1839 closetype = (pktin.type == SSH1_MSG_CHANNEL_CLOSE ? 1 : 2);
1840 send_packet(pktin.type, PKT_INT, c->remoteid, PKT_END);
1841 c->closes |= closetype;
1842 if (c->closes == 3) {
1843 del234(ssh_channels, c);
1844 free(c);
1845 }
1846 }
1847 } else if (pktin.type == SSH1_MSG_CHANNEL_DATA) {
1848 /* Data sent down one of our channels. */
1849 int i = GET_32BIT(pktin.body);
1850 int len = GET_32BIT(pktin.body+4);
1851 unsigned char *p = pktin.body+8;
1852 struct ssh_channel *c;
1853 c = find234(ssh_channels, &i, ssh_channelfind);
1854 if (c) {
1855 switch(c->type) {
1856 case SSH1_SMSG_AGENT_OPEN:
1857 /* Data for an agent message. Buffer it. */
1858 while (len > 0) {
1859 if (c->u.a.lensofar < 4) {
1860 int l = min(4 - c->u.a.lensofar, len);
1861 memcpy(c->u.a.msglen + c->u.a.lensofar, p, l);
1862 p += l; len -= l; c->u.a.lensofar += l;
1863 }
1864 if (c->u.a.lensofar == 4) {
1865 c->u.a.totallen = 4 + GET_32BIT(c->u.a.msglen);
1866 c->u.a.message = malloc(c->u.a.totallen);
1867 memcpy(c->u.a.message, c->u.a.msglen, 4);
1868 }
1869 if (c->u.a.lensofar >= 4 && len > 0) {
1870 int l = min(c->u.a.totallen - c->u.a.lensofar, len);
1871 memcpy(c->u.a.message + c->u.a.lensofar, p, l);
1872 p += l; len -= l; c->u.a.lensofar += l;
1873 }
1874 if (c->u.a.lensofar == c->u.a.totallen) {
1875 void *reply, *sentreply;
1876 int replylen;
1877 agent_query(c->u.a.message, c->u.a.totallen,
1878 &reply, &replylen);
1879 if (reply)
1880 sentreply = reply;
1881 else {
1882 /* Fake SSH_AGENT_FAILURE. */
1883 sentreply = "\0\0\0\1\5";
1884 replylen = 5;
1885 }
1886 send_packet(SSH1_MSG_CHANNEL_DATA,
1887 PKT_INT, c->remoteid,
1888 PKT_INT, replylen,
1889 PKT_DATA, sentreply, replylen,
1890 PKT_END);
1891 if (reply)
1892 free(reply);
1893 free(c->u.a.message);
1894 c->u.a.lensofar = 0;
1895 }
1896 }
1897 break;
1898 }
1899 }
1900 } else if (pktin.type == SSH1_SMSG_SUCCESS) {
1901 /* may be from EXEC_SHELL on some servers */
1902 } else if (pktin.type == SSH1_SMSG_FAILURE) {
1903 /* may be from EXEC_SHELL on some servers
1904 * if no pty is available or in other odd cases. Ignore */
1905 } else if (pktin.type == SSH1_SMSG_EXIT_STATUS) {
1906 send_packet(SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
1907 } else {
1908 bombout(("Strange packet received: type %d", pktin.type));
1909 crReturnV;
1910 }
1911 } else {
1912 while (inlen > 0) {
1913 int len = min(inlen, 512);
1914 send_packet(SSH1_CMSG_STDIN_DATA,
1915 PKT_INT, len, PKT_DATA, in, len, PKT_END);
1916 in += len;
1917 inlen -= len;
1918 }
1919 }
1920 }
1921
1922 crFinishV;
1923 }
1924
1925 /*
1926 * Utility routine for decoding comma-separated strings in KEXINIT.
1927 */
1928 static int in_commasep_string(char *needle, char *haystack, int haylen) {
1929 int needlen = strlen(needle);
1930 while (1) {
1931 /*
1932 * Is it at the start of the string?
1933 */
1934 if (haylen >= needlen && /* haystack is long enough */
1935 !memcmp(needle, haystack, needlen) && /* initial match */
1936 (haylen == needlen || haystack[needlen] == ',')
1937 /* either , or EOS follows */
1938 )
1939 return 1;
1940 /*
1941 * If not, search for the next comma and resume after that.
1942 * If no comma found, terminate.
1943 */
1944 while (haylen > 0 && *haystack != ',')
1945 haylen--, haystack++;
1946 if (haylen == 0)
1947 return 0;
1948 haylen--, haystack++; /* skip over comma itself */
1949 }
1950 }
1951
1952 /*
1953 * SSH2 key creation method.
1954 */
1955 static void ssh2_mkkey(Bignum K, char *H, char chr, char *keyspace) {
1956 SHA_State s;
1957 /* First 20 bytes. */
1958 SHA_Init(&s);
1959 sha_mpint(&s, K);
1960 SHA_Bytes(&s, H, 20);
1961 SHA_Bytes(&s, &chr, 1);
1962 SHA_Bytes(&s, H, 20);
1963 SHA_Final(&s, keyspace);
1964 /* Next 20 bytes. */
1965 SHA_Init(&s);
1966 sha_mpint(&s, K);
1967 SHA_Bytes(&s, H, 20);
1968 SHA_Bytes(&s, keyspace, 20);
1969 SHA_Final(&s, keyspace+20);
1970 }
1971
1972 /*
1973 * Handle the SSH2 transport layer.
1974 */
1975 static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt)
1976 {
1977 static int i, len;
1978 static char *str;
1979 static Bignum e, f, K;
1980 static const struct ssh_mac **maclist;
1981 static int nmacs;
1982 static const struct ssh_cipher *cscipher_tobe = NULL;
1983 static const struct ssh_cipher *sccipher_tobe = NULL;
1984 static const struct ssh_mac *csmac_tobe = NULL;
1985 static const struct ssh_mac *scmac_tobe = NULL;
1986 static const struct ssh_compress *cscomp_tobe = NULL;
1987 static const struct ssh_compress *sccomp_tobe = NULL;
1988 static char *hostkeydata, *sigdata, *keystr, *fingerprint;
1989 static int hostkeylen, siglen;
1990 static unsigned char exchange_hash[20];
1991 static unsigned char keyspace[40];
1992 static const struct ssh_cipher *preferred_cipher;
1993 static const struct ssh_compress *preferred_comp;
1994
1995 crBegin;
1996 random_init();
1997
1998 /*
1999 * Set up the preferred cipher and compression.
2000 */
2001 if (cfg.cipher == CIPHER_BLOWFISH) {
2002 preferred_cipher = &ssh_blowfish_ssh2;
2003 } else if (cfg.cipher == CIPHER_DES) {
2004 logevent("Single DES not supported in SSH2; using 3DES");
2005 preferred_cipher = &ssh_3des_ssh2;
2006 } else if (cfg.cipher == CIPHER_3DES) {
2007 preferred_cipher = &ssh_3des_ssh2;
2008 } else {
2009 /* Shouldn't happen, but we do want to initialise to _something_. */
2010 preferred_cipher = &ssh_3des_ssh2;
2011 }
2012 if (cfg.compression)
2013 preferred_comp = &ssh_zlib;
2014 else
2015 preferred_comp = &ssh_comp_none;
2016
2017 /*
2018 * Be prepared to work around the buggy MAC problem.
2019 */
2020 if (cfg.buggymac)
2021 maclist = buggymacs, nmacs = lenof(buggymacs);
2022 else
2023 maclist = macs, nmacs = lenof(macs);
2024
2025 begin_key_exchange:
2026 /*
2027 * Construct and send our key exchange packet.
2028 */
2029 ssh2_pkt_init(SSH2_MSG_KEXINIT);
2030 for (i = 0; i < 16; i++)
2031 ssh2_pkt_addbyte((unsigned char)random_byte());
2032 /* List key exchange algorithms. */
2033 ssh2_pkt_addstring_start();
2034 for (i = 0; i < lenof(kex_algs); i++) {
2035 ssh2_pkt_addstring_str(kex_algs[i]->name);
2036 if (i < lenof(kex_algs)-1)
2037 ssh2_pkt_addstring_str(",");
2038 }
2039 /* List server host key algorithms. */
2040 ssh2_pkt_addstring_start();
2041 for (i = 0; i < lenof(hostkey_algs); i++) {
2042 ssh2_pkt_addstring_str(hostkey_algs[i]->name);
2043 if (i < lenof(hostkey_algs)-1)
2044 ssh2_pkt_addstring_str(",");
2045 }
2046 /* List client->server encryption algorithms. */
2047 ssh2_pkt_addstring_start();
2048 for (i = 0; i < lenof(ciphers)+1; i++) {
2049 const struct ssh_cipher *c = i==0 ? preferred_cipher : ciphers[i-1];
2050 ssh2_pkt_addstring_str(c->name);
2051 if (i < lenof(ciphers))
2052 ssh2_pkt_addstring_str(",");
2053 }
2054 /* List server->client encryption algorithms. */
2055 ssh2_pkt_addstring_start();
2056 for (i = 0; i < lenof(ciphers)+1; i++) {
2057 const struct ssh_cipher *c = i==0 ? preferred_cipher : ciphers[i-1];
2058 ssh2_pkt_addstring_str(c->name);
2059 if (i < lenof(ciphers))
2060 ssh2_pkt_addstring_str(",");
2061 }
2062 /* List client->server MAC algorithms. */
2063 ssh2_pkt_addstring_start();
2064 for (i = 0; i < nmacs; i++) {
2065 ssh2_pkt_addstring_str(maclist[i]->name);
2066 if (i < nmacs-1)
2067 ssh2_pkt_addstring_str(",");
2068 }
2069 /* List server->client MAC algorithms. */
2070 ssh2_pkt_addstring_start();
2071 for (i = 0; i < nmacs; i++) {
2072 ssh2_pkt_addstring_str(maclist[i]->name);
2073 if (i < nmacs-1)
2074 ssh2_pkt_addstring_str(",");
2075 }
2076 /* List client->server compression algorithms. */
2077 ssh2_pkt_addstring_start();
2078 for (i = 0; i < lenof(compressions)+1; i++) {
2079 const struct ssh_compress *c = i==0 ? preferred_comp : compressions[i-1];
2080 ssh2_pkt_addstring_str(c->name);
2081 if (i < lenof(compressions))
2082 ssh2_pkt_addstring_str(",");
2083 }
2084 /* List server->client compression algorithms. */
2085 ssh2_pkt_addstring_start();
2086 for (i = 0; i < lenof(compressions)+1; i++) {
2087 const struct ssh_compress *c = i==0 ? preferred_comp : compressions[i-1];
2088 ssh2_pkt_addstring_str(c->name);
2089 if (i < lenof(compressions))
2090 ssh2_pkt_addstring_str(",");
2091 }
2092 /* List client->server languages. Empty list. */
2093 ssh2_pkt_addstring_start();
2094 /* List server->client languages. Empty list. */
2095 ssh2_pkt_addstring_start();
2096 /* First KEX packet does _not_ follow, because we're not that brave. */
2097 ssh2_pkt_addbool(FALSE);
2098 /* Reserved. */
2099 ssh2_pkt_adduint32(0);
2100 sha_string(&exhash, pktout.data+5, pktout.length-5);
2101 ssh2_pkt_send();
2102
2103 if (!ispkt) crWaitUntil(ispkt);
2104 sha_string(&exhash, pktin.data+5, pktin.length-5);
2105
2106 /*
2107 * Now examine the other side's KEXINIT to see what we're up
2108 * to.
2109 */
2110 if (pktin.type != SSH2_MSG_KEXINIT) {
2111 bombout(("expected key exchange packet from server"));
2112 crReturn(0);
2113 }
2114 kex = NULL; hostkey = NULL; cscipher_tobe = NULL; sccipher_tobe = NULL;
2115 csmac_tobe = NULL; scmac_tobe = NULL; cscomp_tobe = NULL; sccomp_tobe = NULL;
2116 pktin.savedpos += 16; /* skip garbage cookie */
2117 ssh2_pkt_getstring(&str, &len); /* key exchange algorithms */
2118 for (i = 0; i < lenof(kex_algs); i++) {
2119 if (in_commasep_string(kex_algs[i]->name, str, len)) {
2120 kex = kex_algs[i];
2121 break;
2122 }
2123 }
2124 ssh2_pkt_getstring(&str, &len); /* host key algorithms */
2125 for (i = 0; i < lenof(hostkey_algs); i++) {
2126 if (in_commasep_string(hostkey_algs[i]->name, str, len)) {
2127 hostkey = hostkey_algs[i];
2128 break;
2129 }
2130 }
2131 ssh2_pkt_getstring(&str, &len); /* client->server cipher */
2132 for (i = 0; i < lenof(ciphers)+1; i++) {
2133 const struct ssh_cipher *c = i==0 ? preferred_cipher : ciphers[i-1];
2134 if (in_commasep_string(c->name, str, len)) {
2135 cscipher_tobe = c;
2136 break;
2137 }
2138 }
2139 ssh2_pkt_getstring(&str, &len); /* server->client cipher */
2140 for (i = 0; i < lenof(ciphers)+1; i++) {
2141 const struct ssh_cipher *c = i==0 ? preferred_cipher : ciphers[i-1];
2142 if (in_commasep_string(c->name, str, len)) {
2143 sccipher_tobe = c;
2144 break;
2145 }
2146 }
2147 ssh2_pkt_getstring(&str, &len); /* client->server mac */
2148 for (i = 0; i < nmacs; i++) {
2149 if (in_commasep_string(maclist[i]->name, str, len)) {
2150 csmac_tobe = maclist[i];
2151 break;
2152 }
2153 }
2154 ssh2_pkt_getstring(&str, &len); /* server->client mac */
2155 for (i = 0; i < nmacs; i++) {
2156 if (in_commasep_string(maclist[i]->name, str, len)) {
2157 scmac_tobe = maclist[i];
2158 break;
2159 }
2160 }
2161 ssh2_pkt_getstring(&str, &len); /* client->server compression */
2162 for (i = 0; i < lenof(compressions)+1; i++) {
2163 const struct ssh_compress *c = i==0 ? preferred_comp : compressions[i-1];
2164 if (in_commasep_string(c->name, str, len)) {
2165 cscomp_tobe = c;
2166 break;
2167 }
2168 }
2169 ssh2_pkt_getstring(&str, &len); /* server->client compression */
2170 for (i = 0; i < lenof(compressions)+1; i++) {
2171 const struct ssh_compress *c = i==0 ? preferred_comp : compressions[i-1];
2172 if (in_commasep_string(c->name, str, len)) {
2173 sccomp_tobe = c;
2174 break;
2175 }
2176 }
2177
2178 /*
2179 * Currently we only support Diffie-Hellman and DSS, so let's
2180 * bomb out if those aren't selected.
2181 */
2182 if (kex != &ssh_diffiehellman || hostkey != &ssh_dss) {
2183 bombout(("internal fault: chaos in SSH 2 transport layer"));
2184 crReturn(0);
2185 }
2186
2187 /*
2188 * Now we begin the fun. Generate and send e for Diffie-Hellman.
2189 */
2190 e = dh_create_e();
2191 ssh2_pkt_init(SSH2_MSG_KEXDH_INIT);
2192 ssh2_pkt_addmp(e);
2193 ssh2_pkt_send();
2194
2195 crWaitUntil(ispkt);
2196 if (pktin.type != SSH2_MSG_KEXDH_REPLY) {
2197 bombout(("expected key exchange packet from server"));
2198 crReturn(0);
2199 }
2200 ssh2_pkt_getstring(&hostkeydata, &hostkeylen);
2201 f = ssh2_pkt_getmp();
2202 ssh2_pkt_getstring(&sigdata, &siglen);
2203
2204 K = dh_find_K(f);
2205
2206 sha_string(&exhash, hostkeydata, hostkeylen);
2207 sha_mpint(&exhash, e);
2208 sha_mpint(&exhash, f);
2209 sha_mpint(&exhash, K);
2210 SHA_Final(&exhash, exchange_hash);
2211
2212 #if 0
2213 debug(("Exchange hash is:\r\n"));
2214 for (i = 0; i < 20; i++)
2215 debug((" %02x", exchange_hash[i]));
2216 debug(("\r\n"));
2217 #endif
2218
2219 hostkey->setkey(hostkeydata, hostkeylen);
2220 if (!hostkey->verifysig(sigdata, siglen, exchange_hash, 20)) {
2221 bombout(("Server failed host key check"));
2222 crReturn(0);
2223 }
2224
2225 /*
2226 * Expect SSH2_MSG_NEWKEYS from server.
2227 */
2228 crWaitUntil(ispkt);
2229 if (pktin.type != SSH2_MSG_NEWKEYS) {
2230 bombout(("expected new-keys packet from server"));
2231 crReturn(0);
2232 }
2233
2234 /*
2235 * Authenticate remote host: verify host key. (We've already
2236 * checked the signature of the exchange hash.)
2237 */
2238 keystr = hostkey->fmtkey();
2239 fingerprint = hostkey->fingerprint();
2240 verify_ssh_host_key(savedhost, savedport, hostkey->keytype,
2241 keystr, fingerprint);
2242 logevent("Host key fingerprint is:");
2243 logevent(fingerprint);
2244 free(fingerprint);
2245 free(keystr);
2246
2247 /*
2248 * Send SSH2_MSG_NEWKEYS.
2249 */
2250 ssh2_pkt_init(SSH2_MSG_NEWKEYS);
2251 ssh2_pkt_send();
2252
2253 /*
2254 * Create and initialise session keys.
2255 */
2256 cscipher = cscipher_tobe;
2257 sccipher = sccipher_tobe;
2258 csmac = csmac_tobe;
2259 scmac = scmac_tobe;
2260 cscomp = cscomp_tobe;
2261 sccomp = sccomp_tobe;
2262 cscomp->compress_init();
2263 sccomp->decompress_init();
2264 /*
2265 * Set IVs after keys.
2266 */
2267 ssh2_mkkey(K, exchange_hash, 'C', keyspace); cscipher->setcskey(keyspace);
2268 ssh2_mkkey(K, exchange_hash, 'D', keyspace); cscipher->setsckey(keyspace);
2269 ssh2_mkkey(K, exchange_hash, 'A', keyspace); cscipher->setcsiv(keyspace);
2270 ssh2_mkkey(K, exchange_hash, 'B', keyspace); sccipher->setsciv(keyspace);
2271 ssh2_mkkey(K, exchange_hash, 'E', keyspace); csmac->setcskey(keyspace);
2272 ssh2_mkkey(K, exchange_hash, 'F', keyspace); scmac->setsckey(keyspace);
2273
2274 /*
2275 * Now we're encrypting. Begin returning 1 to the protocol main
2276 * function so that other things can run on top of the
2277 * transport. If we ever see a KEXINIT, we must go back to the
2278 * start.
2279 */
2280 do {
2281 crReturn(1);
2282 } while (!(ispkt && pktin.type == SSH2_MSG_KEXINIT));
2283 goto begin_key_exchange;
2284
2285 crFinish(1);
2286 }
2287
2288 /*
2289 * Handle the SSH2 userauth and connection layers.
2290 */
2291 static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt)
2292 {
2293 static unsigned long remote_winsize;
2294 static unsigned long remote_maxpkt;
2295
2296 crBegin;
2297
2298 /*
2299 * Request userauth protocol, and await a response to it.
2300 */
2301 ssh2_pkt_init(SSH2_MSG_SERVICE_REQUEST);
2302 ssh2_pkt_addstring("ssh-userauth");
2303 ssh2_pkt_send();
2304 crWaitUntilV(ispkt);
2305 if (pktin.type != SSH2_MSG_SERVICE_ACCEPT) {
2306 bombout(("Server refused user authentication protocol"));
2307 crReturnV;
2308 }
2309
2310 /*
2311 * FIXME: currently we support only password authentication.
2312 * (This places us technically in violation of the SSH2 spec.
2313 * We must fix this.)
2314 */
2315 while (1) {
2316 /*
2317 * Get a username and a password.
2318 */
2319 static char username[100];
2320 static char password[100];
2321 static int pos = 0;
2322 static char c;
2323
2324 if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
2325 c_write("login as: ", 10);
2326 ssh_send_ok = 1;
2327 while (pos >= 0) {
2328 crWaitUntilV(!ispkt);
2329 while (inlen--) switch (c = *in++) {
2330 case 10: case 13:
2331 username[pos] = 0;
2332 pos = -1;
2333 break;
2334 case 8: case 127:
2335 if (pos > 0) {
2336 c_write("\b \b", 3);
2337 pos--;
2338 }
2339 break;
2340 case 21: case 27:
2341 while (pos > 0) {
2342 c_write("\b \b", 3);
2343 pos--;
2344 }
2345 break;
2346 case 3: case 4:
2347 random_save_seed();
2348 exit(0);
2349 break;
2350 default:
2351 if (((c >= ' ' && c <= '~') ||
2352 ((unsigned char)c >= 160)) && pos < 40) {
2353 username[pos++] = c;
2354 c_write(&c, 1);
2355 }
2356 break;
2357 }
2358 }
2359 c_write("\r\n", 2);
2360 username[strcspn(username, "\n\r")] = '\0';
2361 } else {
2362 char stuff[200];
2363 strncpy(username, cfg.username, 99);
2364 username[99] = '\0';
2365 if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
2366 sprintf(stuff, "Using username \"%s\".\r\n", username);
2367 c_write(stuff, strlen(stuff));
2368 }
2369 }
2370
2371 if (ssh_get_password) {
2372 char prompt[200];
2373 sprintf(prompt, "%.90s@%.90s's password: ", username, savedhost);
2374 if (!ssh_get_password(prompt, password, sizeof(password))) {
2375 /*
2376 * get_password failed to get a password (for
2377 * example because one was supplied on the command
2378 * line which has already failed to work).
2379 * Terminate.
2380 */
2381 logevent("No more passwords to try");
2382 ssh_state = SSH_STATE_CLOSED;
2383 crReturnV;
2384 }
2385 } else {
2386 c_write("password: ", 10);
2387 ssh_send_ok = 1;
2388
2389 pos = 0;
2390 while (pos >= 0) {
2391 crWaitUntilV(!ispkt);
2392 while (inlen--) switch (c = *in++) {
2393 case 10: case 13:
2394 password[pos] = 0;
2395 pos = -1;
2396 break;
2397 case 8: case 127:
2398 if (pos > 0)
2399 pos--;
2400 break;
2401 case 21: case 27:
2402 pos = 0;
2403 break;
2404 case 3: case 4:
2405 random_save_seed();
2406 exit(0);
2407 break;
2408 default:
2409 if (((c >= ' ' && c <= '~') ||
2410 ((unsigned char)c >= 160)) && pos < 40)
2411 password[pos++] = c;
2412 break;
2413 }
2414 }
2415 c_write("\r\n", 2);
2416 }
2417
2418 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
2419 ssh2_pkt_addstring(username);
2420 ssh2_pkt_addstring("ssh-connection"); /* service requested */
2421 ssh2_pkt_addstring("password");
2422 ssh2_pkt_addbool(FALSE);
2423 ssh2_pkt_addstring(password);
2424 ssh2_pkt_send();
2425
2426 crWaitUntilV(ispkt);
2427 if (pktin.type != SSH2_MSG_USERAUTH_SUCCESS) {
2428 c_write("Access denied\r\n", 15);
2429 logevent("Authentication refused");
2430 } else
2431 break;
2432 }
2433
2434 /*
2435 * Now we're authenticated for the connection protocol. The
2436 * connection protocol will automatically have started at this
2437 * point; there's no need to send SERVICE_REQUEST.
2438 */
2439
2440 /*
2441 * So now create a channel with a session in it.
2442 */
2443 mainchan = malloc(sizeof(struct ssh_channel));
2444 mainchan->localid = 100; /* as good as any */
2445 ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN);
2446 ssh2_pkt_addstring("session");
2447 ssh2_pkt_adduint32(mainchan->localid);
2448 ssh2_pkt_adduint32(0x8000UL); /* our window size */
2449 ssh2_pkt_adduint32(0x4000UL); /* our max pkt size */
2450 ssh2_pkt_send();
2451 crWaitUntilV(ispkt);
2452 if (pktin.type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
2453 bombout(("Server refused to open a session"));
2454 crReturnV;
2455 /* FIXME: error data comes back in FAILURE packet */
2456 }
2457 if (ssh2_pkt_getuint32() != mainchan->localid) {
2458 bombout(("Server's channel confirmation cited wrong channel"));
2459 crReturnV;
2460 }
2461 mainchan->remoteid = ssh2_pkt_getuint32();
2462 mainchan->u.v2.remwindow = ssh2_pkt_getuint32();
2463 mainchan->u.v2.remmaxpkt = ssh2_pkt_getuint32();
2464 mainchan->u.v2.outbuffer = NULL;
2465 mainchan->u.v2.outbuflen = mainchan->u.v2.outbufsize = 0;
2466 logevent("Opened channel for session");
2467
2468 /*
2469 * Now allocate a pty for the session.
2470 */
2471 if (!cfg.nopty) {
2472 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
2473 ssh2_pkt_adduint32(mainchan->remoteid); /* recipient channel */
2474 ssh2_pkt_addstring("pty-req");
2475 ssh2_pkt_addbool(1); /* want reply */
2476 ssh2_pkt_addstring(cfg.termtype);
2477 ssh2_pkt_adduint32(cols);
2478 ssh2_pkt_adduint32(rows);
2479 ssh2_pkt_adduint32(0); /* pixel width */
2480 ssh2_pkt_adduint32(0); /* pixel height */
2481 ssh2_pkt_addstring_start();
2482 ssh2_pkt_addstring_data("\0", 1);/* TTY_OP_END, no special options */
2483 ssh2_pkt_send();
2484 ssh_state = SSH_STATE_INTERMED;
2485
2486 do {
2487 crWaitUntilV(ispkt);
2488 if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
2489 /* FIXME: be able to handle other channels here */
2490 if (ssh2_pkt_getuint32() != mainchan->localid)
2491 continue; /* wrong channel */
2492 mainchan->u.v2.remwindow += ssh2_pkt_getuint32();
2493 }
2494 } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
2495
2496 if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
2497 if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
2498 bombout(("Server got confused by pty request"));
2499 crReturnV;
2500 }
2501 c_write("Server refused to allocate pty\r\n", 32);
2502 } else {
2503 logevent("Allocated pty");
2504 }
2505 }
2506
2507 /*
2508 * Start a shell or a remote command.
2509 */
2510 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
2511 ssh2_pkt_adduint32(mainchan->remoteid); /* recipient channel */
2512 if (*cfg.remote_cmd) {
2513 ssh2_pkt_addstring("exec");
2514 ssh2_pkt_addbool(1); /* want reply */
2515 ssh2_pkt_addstring(cfg.remote_cmd);
2516 } else {
2517 ssh2_pkt_addstring("shell");
2518 ssh2_pkt_addbool(1); /* want reply */
2519 }
2520 ssh2_pkt_send();
2521 do {
2522 crWaitUntilV(ispkt);
2523 if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
2524 /* FIXME: be able to handle other channels here */
2525 if (ssh2_pkt_getuint32() != mainchan->localid)
2526 continue; /* wrong channel */
2527 mainchan->u.v2.remwindow += ssh2_pkt_getuint32();
2528 }
2529 } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
2530 if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
2531 if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
2532 bombout(("Server got confused by shell/command request"));
2533 crReturnV;
2534 }
2535 bombout(("Server refused to start a shell/command"));
2536 crReturnV;
2537 } else {
2538 logevent("Started a shell/command");
2539 }
2540
2541 ssh_state = SSH_STATE_SESSION;
2542 if (size_needed)
2543 ssh_size();
2544
2545 /*
2546 * Transfer data!
2547 */
2548 ssh_send_ok = 1;
2549 begin_session();
2550 while (1) {
2551 static int try_send;
2552 crReturnV;
2553 try_send = FALSE;
2554 if (ispkt) {
2555 if (pktin.type == SSH2_MSG_CHANNEL_DATA ||
2556 pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA) {
2557 char *data;
2558 int length;
2559 /* FIXME: be able to handle other channels here */
2560 if (ssh2_pkt_getuint32() != mainchan->localid)
2561 continue; /* wrong channel */
2562 if (pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
2563 ssh2_pkt_getuint32() != SSH2_EXTENDED_DATA_STDERR)
2564 continue; /* extended but not stderr */
2565 ssh2_pkt_getstring(&data, &length);
2566 if (data) {
2567 from_backend(pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA,
2568 data, length);
2569 /*
2570 * Enlarge the window again at the remote side,
2571 * just in case it ever runs down and they fail
2572 * to send us any more data.
2573 */
2574 ssh2_pkt_init(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
2575 ssh2_pkt_adduint32(mainchan->remoteid);
2576 ssh2_pkt_adduint32(length);
2577 ssh2_pkt_send();
2578 }
2579 } else if (pktin.type == SSH2_MSG_DISCONNECT) {
2580 ssh_state = SSH_STATE_CLOSED;
2581 logevent("Received disconnect message");
2582 crReturnV;
2583 } else if (pktin.type == SSH2_MSG_CHANNEL_REQUEST) {
2584 continue; /* exit status et al; ignore (FIXME?) */
2585 } else if (pktin.type == SSH2_MSG_CHANNEL_EOF) {
2586 continue; /* remote sends EOF; ignore */
2587 } else if (pktin.type == SSH2_MSG_CHANNEL_CLOSE) {
2588 /* FIXME: be able to handle other channels here */
2589 if (ssh2_pkt_getuint32() != mainchan->localid)
2590 continue; /* wrong channel */
2591 ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE);
2592 ssh2_pkt_adduint32(mainchan->remoteid);
2593 ssh2_pkt_send();
2594 /* FIXME: mark the channel as closed */
2595 if (1 /* FIXME: "all channels are closed" */) {
2596 logevent("All channels closed. Disconnecting");
2597 ssh2_pkt_init(SSH2_MSG_DISCONNECT);
2598 ssh2_pkt_adduint32(SSH2_DISCONNECT_BY_APPLICATION);
2599 ssh2_pkt_addstring("All open channels closed");
2600 ssh2_pkt_addstring("en"); /* language tag */
2601 ssh2_pkt_send();
2602 ssh_state = SSH_STATE_CLOSED;
2603 crReturnV;
2604 }
2605 continue; /* remote sends close; ignore (FIXME) */
2606 } else if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
2607 /* FIXME: be able to handle other channels here */
2608 if (ssh2_pkt_getuint32() != mainchan->localid)
2609 continue; /* wrong channel */
2610 mainchan->u.v2.remwindow += ssh2_pkt_getuint32();
2611 try_send = TRUE;
2612 } else {
2613 bombout(("Strange packet received: type %d", pktin.type));
2614 crReturnV;
2615 }
2616 } else {
2617 /*
2618 * We have spare data. Add it to the channel buffer.
2619 */
2620 if (mainchan->u.v2.outbufsize <
2621 mainchan->u.v2.outbuflen + inlen) {
2622 mainchan->u.v2.outbufsize =
2623 mainchan->u.v2.outbuflen + inlen + 1024;
2624 mainchan->u.v2.outbuffer = srealloc(mainchan->u.v2.outbuffer,
2625 mainchan->u.v2.outbufsize);
2626 }
2627 memcpy(mainchan->u.v2.outbuffer + mainchan->u.v2.outbuflen,
2628 in, inlen);
2629 mainchan->u.v2.outbuflen += inlen;
2630 try_send = TRUE;
2631 }
2632 if (try_send) {
2633 /*
2634 * Try to send data on the channel if we can. (FIXME:
2635 * on _all_ channels.)
2636 */
2637 while (mainchan->u.v2.remwindow > 0 &&
2638 mainchan->u.v2.outbuflen > 0) {
2639 unsigned len = mainchan->u.v2.remwindow;
2640 if (len > mainchan->u.v2.outbuflen)
2641 len = mainchan->u.v2.outbuflen;
2642 if (len > mainchan->u.v2.remmaxpkt)
2643 len = mainchan->u.v2.remmaxpkt;
2644 ssh2_pkt_init(SSH2_MSG_CHANNEL_DATA);
2645 ssh2_pkt_adduint32(mainchan->remoteid);
2646 ssh2_pkt_addstring_start();
2647 ssh2_pkt_addstring_data(mainchan->u.v2.outbuffer, len);
2648 ssh2_pkt_send();
2649 mainchan->u.v2.outbuflen -= len;
2650 memmove(mainchan->u.v2.outbuffer, mainchan->u.v2.outbuffer+len,
2651 mainchan->u.v2.outbuflen);
2652 mainchan->u.v2.remwindow -= len;
2653 }
2654 }
2655 }
2656
2657 crFinishV;
2658 }
2659
2660 /*
2661 * Handle the top-level SSH2 protocol.
2662 */
2663 static void ssh2_protocol(unsigned char *in, int inlen, int ispkt)
2664 {
2665 if (do_ssh2_transport(in, inlen, ispkt) == 0)
2666 return;
2667 do_ssh2_authconn(in, inlen, ispkt);
2668 }
2669
2670 /*
2671 * Called to set up the connection.
2672 *
2673 * Returns an error message, or NULL on success.
2674 */
2675 static char *ssh_init (char *host, int port, char **realhost) {
2676 char *p;
2677
2678 #ifdef MSCRYPTOAPI
2679 if(crypto_startup() == 0)
2680 return "Microsoft high encryption pack not installed!";
2681 #endif
2682
2683 ssh_send_ok = 0;
2684
2685 p = connect_to_host(host, port, realhost);
2686 if (p != NULL)
2687 return p;
2688
2689 return NULL;
2690 }
2691
2692 /*
2693 * Called to send data down the Telnet connection.
2694 */
2695 static void ssh_send (char *buf, int len) {
2696 if (s == NULL || ssh_protocol == NULL)
2697 return;
2698
2699 ssh_protocol(buf, len, 0);
2700 }
2701
2702 /*
2703 * Called to set the size of the window from SSH's POV.
2704 */
2705 static void ssh_size(void) {
2706 switch (ssh_state) {
2707 case SSH_STATE_BEFORE_SIZE:
2708 case SSH_STATE_CLOSED:
2709 break; /* do nothing */
2710 case SSH_STATE_INTERMED:
2711 size_needed = TRUE; /* buffer for later */
2712 break;
2713 case SSH_STATE_SESSION:
2714 if (!cfg.nopty) {
2715 if (ssh_version == 1) {
2716 send_packet(SSH1_CMSG_WINDOW_SIZE,
2717 PKT_INT, rows, PKT_INT, cols,
2718 PKT_INT, 0, PKT_INT, 0, PKT_END);
2719 } else {
2720 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
2721 ssh2_pkt_adduint32(mainchan->remoteid);
2722 ssh2_pkt_addstring("window-change");
2723 ssh2_pkt_addbool(0);
2724 ssh2_pkt_adduint32(cols);
2725 ssh2_pkt_adduint32(rows);
2726 ssh2_pkt_adduint32(0);
2727 ssh2_pkt_adduint32(0);
2728 ssh2_pkt_send();
2729 }
2730 }
2731 }
2732 }
2733
2734 /*
2735 * Send Telnet special codes. TS_EOF is useful for `plink', so you
2736 * can send an EOF and collect resulting output (e.g. `plink
2737 * hostname sort').
2738 */
2739 static void ssh_special (Telnet_Special code) {
2740 if (code == TS_EOF) {
2741 if (ssh_version == 1) {
2742 send_packet(SSH1_CMSG_EOF, PKT_END);
2743 } else {
2744 ssh2_pkt_init(SSH2_MSG_CHANNEL_EOF);
2745 ssh2_pkt_adduint32(mainchan->remoteid);
2746 ssh2_pkt_send();
2747 }
2748 logevent("Sent EOF message");
2749 } else if (code == TS_PING) {
2750 if (ssh_version == 1) {
2751 send_packet(SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
2752 } else {
2753 ssh2_pkt_init(SSH2_MSG_IGNORE);
2754 ssh2_pkt_addstring_start();
2755 ssh2_pkt_send();
2756 }
2757 } else {
2758 /* do nothing */
2759 }
2760 }
2761
2762 static Socket ssh_socket(void) { return s; }
2763
2764 static int ssh_sendok(void) { return ssh_send_ok; }
2765
2766 Backend ssh_backend = {
2767 ssh_init,
2768 ssh_send,
2769 ssh_size,
2770 ssh_special,
2771 ssh_socket,
2772 ssh_sendok,
2773 22
2774 };
Local modifications for Simon Tatham's `PuTTY' SSH client and terminal emulator