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Remove unnecessary printfs from Minefield
[u/mdw/putty] / ssh.c
CommitLineData
8df7a775 1#include <windows.h>
374330e2 2#include <stdio.h>
3#include <stdlib.h>
fb09bf1c 4#include <stdarg.h>
5#include <assert.h>
374330e2 6
7#include "putty.h"
dacbd0e8 8#include "tree234.h"
fb09bf1c 9#include "ssh.h"
374330e2 10
11#ifndef FALSE
12#define FALSE 0
13#endif
14#ifndef TRUE
15#define TRUE 1
16#endif
17
fb09bf1c 18#define logevent(s) { logevent(s); \
67779be7 19 if ((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)) \
fb09bf1c 20 fprintf(stderr, "%s\n", s); }
21
8df7a775 22#define bombout(msg) ( ssh_state = SSH_STATE_CLOSED, sk_close(s), \
23 s = NULL, connection_fatal msg )
8d5de777 24
d211621f 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 */
4ba9b64b 54#define SSH1_CMSG_REQUEST_COMPRESSION 37 /* 0x25 */
d211621f 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
9005f3ba 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
d211621f 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 */
fb09bf1c 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
7cca0d81 136enum { PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR, PKT_BIGNUM };
972a41c8 137
374330e2 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)
fb09bf1c 154#define crWaitUntil(c) do { crReturn(0); } while (!(c))
7cca0d81 155#define crWaitUntilV(c) do { crReturnV; } while (!(c))
374330e2 156
57476f6b 157extern const struct ssh_cipher ssh_3des;
158extern const struct ssh_cipher ssh_3des_ssh2;
159extern const struct ssh_cipher ssh_des;
160extern const struct ssh_cipher ssh_blowfish_ssh1;
161extern const struct ssh_cipher ssh_blowfish_ssh2;
e5574168 162
5e8358ad 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.)
5e8358ad 168 */
57476f6b 169const static struct ssh_cipher *ciphers[] = { &ssh_blowfish_ssh2, &ssh_3des_ssh2 };
e5574168 170
57476f6b 171extern const struct ssh_kex ssh_diffiehellman;
172const static struct ssh_kex *kex_algs[] = { &ssh_diffiehellman };
e5574168 173
e055a386 174extern const struct ssh_signkey ssh_dss;
175const static struct ssh_signkey *hostkey_algs[] = { &ssh_dss };
e5574168 176
8b2715b2 177extern const struct ssh_mac ssh_md5, ssh_sha1, ssh_sha1_buggy;
e5574168 178
d39f364a 179static void nullmac_key(unsigned char *key) { }
e5574168 180static void nullmac_generate(unsigned char *blk, int len, unsigned long seq) { }
181static int nullmac_verify(unsigned char *blk, int len, unsigned long seq) { return 1; }
57476f6b 182const static struct ssh_mac ssh_mac_none = {
d39f364a 183 nullmac_key, nullmac_key, nullmac_generate, nullmac_verify, "none", 0
e5574168 184};
8b2715b2 185const static struct ssh_mac *macs[] = {
186 &ssh_sha1, &ssh_md5, &ssh_mac_none };
187const static struct ssh_mac *buggymacs[] = {
188 &ssh_sha1_buggy, &ssh_md5, &ssh_mac_none };
e5574168 189
4ba9b64b 190static void ssh_comp_none_init(void) { }
191static int ssh_comp_none_block(unsigned char *block, int len,
192 unsigned char **outblock, int *outlen) {
193 return 0;
194}
57476f6b 195const static struct ssh_compress ssh_comp_none = {
4ba9b64b 196 "none",
197 ssh_comp_none_init, ssh_comp_none_block,
198 ssh_comp_none_init, ssh_comp_none_block
e5574168 199};
4ba9b64b 200extern const struct ssh_compress ssh_zlib;
201const static struct ssh_compress *compressions[] = {
202 &ssh_zlib, &ssh_comp_none };
374330e2 203
dacbd0e8 204/*
205 * 2-3-4 tree storing channels.
206 */
207struct ssh_channel {
d211621f 208 unsigned remoteid, localid;
dacbd0e8 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;
d211621f 217 struct ssh2_data_channel {
218 unsigned char *outbuffer;
219 unsigned outbuflen, outbufsize;
220 unsigned remwindow, remmaxpkt;
221 } v2;
dacbd0e8 222 } u;
223};
57476f6b 224
225struct Packet {
226 long length;
227 int type;
228 unsigned char *data;
229 unsigned char *body;
230 long savedpos;
231 long maxlen;
232};
233
234static SHA_State exhash;
235
8df7a775 236static Socket s = NULL;
57476f6b 237
238static unsigned char session_key[32];
4ba9b64b 239static int ssh1_compressing;
db7d555c 240static int ssh_agentfwd_enabled;
57476f6b 241static const struct ssh_cipher *cipher = NULL;
242static const struct ssh_cipher *cscipher = NULL;
243static const struct ssh_cipher *sccipher = NULL;
244static const struct ssh_mac *csmac = NULL;
245static const struct ssh_mac *scmac = NULL;
246static const struct ssh_compress *cscomp = NULL;
247static const struct ssh_compress *sccomp = NULL;
248static const struct ssh_kex *kex = NULL;
e055a386 249static const struct ssh_signkey *hostkey = NULL;
57476f6b 250int (*ssh_get_password)(const char *prompt, char *str, int maxlen) = NULL;
251
252static char *savedhost;
253static int savedport;
254static int ssh_send_ok;
255
dacbd0e8 256static tree234 *ssh_channels; /* indexed by local id */
57476f6b 257static struct ssh_channel *mainchan; /* primary session channel */
258
259static 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
266static int size_needed = FALSE;
267
268static struct Packet pktin = { 0, 0, NULL, NULL, 0 };
269static struct Packet pktout = { 0, 0, NULL, NULL, 0 };
270
271static int ssh_version;
272static void (*ssh_protocol)(unsigned char *in, int inlen, int ispkt);
273static void ssh1_protocol(unsigned char *in, int inlen, int ispkt);
274static void ssh2_protocol(unsigned char *in, int inlen, int ispkt);
275static void ssh_size(void);
276
277static int (*s_rdpkt)(unsigned char **data, int *datalen);
278
279static 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
960e736a 287static 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
dacbd0e8 294static 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}
301static int ssh_channelfind(void *av, void *bv) {
d211621f 302 unsigned *a = (unsigned *)av;
dacbd0e8 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
374330e2 309static void c_write (char *buf, int len) {
67779be7 310 if ((flags & FLAG_STDERR)) {
4017be6d 311 int i;
312 for (i = 0; i < len; i++)
313 if (buf[i] != '\r')
314 fputc(buf[i], stderr);
fb09bf1c 315 return;
316 }
fe50e814 317 from_backend(1, buf, len);
3bdaf79d 318}
319
fb09bf1c 320/*
321 * Collect incoming data in the incoming packet buffer.
e5574168 322 * Decipher and verify the packet when it is completely read.
323 * Drop SSH1_MSG_DEBUG and SSH1_MSG_IGNORE packets.
fb09bf1c 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 */
e5574168 328static int ssh1_rdpkt(unsigned char **data, int *datalen)
fb09bf1c 329{
57476f6b 330 struct rdpkt1_state_tag *st = &rdpkt1_state;
374330e2 331
332 crBegin;
374330e2 333
fb09bf1c 334next_packet:
37508af4 335
fb09bf1c 336 pktin.type = 0;
337 pktin.length = 0;
374330e2 338
57476f6b 339 for (st->i = st->len = 0; st->i < 4; st->i++) {
fb09bf1c 340 while ((*datalen) == 0)
57476f6b 341 crReturn(4-st->i);
342 st->len = (st->len << 8) + **data;
fb09bf1c 343 (*data)++, (*datalen)--;
344 }
374330e2 345
fb09bf1c 346#ifdef FWHACK
57476f6b 347 if (st->len == 0x52656d6f) { /* "Remo"te server has closed ... */
348 st->len = 0x300; /* big enough to carry to end */
fb09bf1c 349 }
350#endif
374330e2 351
57476f6b 352 st->pad = 8 - (st->len % 8);
353 st->biglen = st->len + st->pad;
354 pktin.length = st->len - 5;
fb09bf1c 355
57476f6b 356 if (pktin.maxlen < st->biglen) {
357 pktin.maxlen = st->biglen;
dcbde236 358 pktin.data = (pktin.data == NULL ? smalloc(st->biglen+APIEXTRA) :
359 srealloc(pktin.data, st->biglen+APIEXTRA));
fb09bf1c 360 if (!pktin.data)
361 fatalbox("Out of memory");
362 }
374330e2 363
57476f6b 364 st->to_read = st->biglen;
365 st->p = pktin.data;
366 while (st->to_read > 0) {
367 st->chunk = st->to_read;
fb09bf1c 368 while ((*datalen) == 0)
57476f6b 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;
fb09bf1c 377 }
374330e2 378
fb09bf1c 379 if (cipher)
57476f6b 380 cipher->decrypt(pktin.data, st->biglen);
698a5108 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
374330e2 387
57476f6b 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) {
8d5de777 391 bombout(("Incorrect CRC received on packet"));
392 crReturn(0);
fb09bf1c 393 }
572f871e 394
4ba9b64b 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;
dcbde236 412 pktin.data = srealloc(pktin.data, pktin.maxlen+APIEXTRA);
58298665 413 pktin.body = pktin.data + st->pad + 1;
4ba9b64b 414 if (!pktin.data)
415 fatalbox("Out of memory");
416 }
417
418 memcpy(pktin.body-1, decompblk, decomplen);
dcbde236 419 sfree(decompblk);
4ba9b64b 420 pktin.length = decomplen-1;
421#if 0
422 debug(("Packet payload post-decompression:\n"));
423 for (i = -1; i < pktin.length; i++)
424 debug((" %02x", (unsigned char)pktin.body[i]));
425 debug(("\r\n"));
426#endif
427 }
428
e5574168 429 if (pktin.type == SSH1_SMSG_STDOUT_DATA ||
430 pktin.type == SSH1_SMSG_STDERR_DATA ||
431 pktin.type == SSH1_MSG_DEBUG ||
18515c51 432 pktin.type == SSH1_SMSG_AUTH_TIS_CHALLENGE ||
433 pktin.type == SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
fb09bf1c 434 long strlen = GET_32BIT(pktin.body);
8d5de777 435 if (strlen + 4 != pktin.length) {
436 bombout(("Received data packet with bogus string length"));
437 crReturn(0);
438 }
fb09bf1c 439 }
440
4ba9b64b 441 pktin.type = pktin.body[-1];
442
e5574168 443 if (pktin.type == SSH1_MSG_DEBUG) {
fb09bf1c 444 /* log debug message */
445 char buf[80];
446 int strlen = GET_32BIT(pktin.body);
447 strcpy(buf, "Remote: ");
448 if (strlen > 70) strlen = 70;
449 memcpy(buf+8, pktin.body+4, strlen);
450 buf[8+strlen] = '\0';
451 logevent(buf);
452 goto next_packet;
e5574168 453 } else if (pktin.type == SSH1_MSG_IGNORE) {
fb09bf1c 454 /* do nothing */
455 goto next_packet;
456 }
457
458 crFinish(0);
459}
460
e5574168 461static int ssh2_rdpkt(unsigned char **data, int *datalen)
462{
960e736a 463 struct rdpkt2_state_tag *st = &rdpkt2_state;
e5574168 464
465 crBegin;
466
467next_packet:
e5574168 468 pktin.type = 0;
469 pktin.length = 0;
960e736a 470 if (sccipher)
471 st->cipherblk = sccipher->blksize;
e5574168 472 else
960e736a 473 st->cipherblk = 8;
474 if (st->cipherblk < 8)
475 st->cipherblk = 8;
476
477 if (pktin.maxlen < st->cipherblk) {
478 pktin.maxlen = st->cipherblk;
dcbde236 479 pktin.data = (pktin.data == NULL ? smalloc(st->cipherblk+APIEXTRA) :
480 srealloc(pktin.data, st->cipherblk+APIEXTRA));
e5574168 481 if (!pktin.data)
482 fatalbox("Out of memory");
483 }
484
485 /*
486 * Acquire and decrypt the first block of the packet. This will
487 * contain the length and padding details.
488 */
960e736a 489 for (st->i = st->len = 0; st->i < st->cipherblk; st->i++) {
e5574168 490 while ((*datalen) == 0)
960e736a 491 crReturn(st->cipherblk-st->i);
492 pktin.data[st->i] = *(*data)++;
e5574168 493 (*datalen)--;
494 }
495#ifdef FWHACK
496 if (!memcmp(pktin.data, "Remo", 4)) {/* "Remo"te server has closed ... */
497 /* FIXME */
498 }
499#endif
500 if (sccipher)
960e736a 501 sccipher->decrypt(pktin.data, st->cipherblk);
e5574168 502
503 /*
504 * Now get the length and padding figures.
505 */
960e736a 506 st->len = GET_32BIT(pktin.data);
507 st->pad = pktin.data[4];
e5574168 508
509 /*
510 * This enables us to deduce the payload length.
511 */
960e736a 512 st->payload = st->len - st->pad - 1;
e5574168 513
960e736a 514 pktin.length = st->payload + 5;
e5574168 515
516 /*
517 * So now we can work out the total packet length.
518 */
960e736a 519 st->packetlen = st->len + 4;
520 st->maclen = scmac ? scmac->len : 0;
e5574168 521
522 /*
523 * Adjust memory allocation if packet is too big.
524 */
960e736a 525 if (pktin.maxlen < st->packetlen+st->maclen) {
526 pktin.maxlen = st->packetlen+st->maclen;
dcbde236 527 pktin.data = (pktin.data == NULL ? smalloc(pktin.maxlen+APIEXTRA) :
528 srealloc(pktin.data, pktin.maxlen+APIEXTRA));
e5574168 529 if (!pktin.data)
530 fatalbox("Out of memory");
531 }
532
533 /*
534 * Read and decrypt the remainder of the packet.
535 */
960e736a 536 for (st->i = st->cipherblk; st->i < st->packetlen + st->maclen; st->i++) {
e5574168 537 while ((*datalen) == 0)
960e736a 538 crReturn(st->packetlen + st->maclen - st->i);
539 pktin.data[st->i] = *(*data)++;
e5574168 540 (*datalen)--;
541 }
542 /* Decrypt everything _except_ the MAC. */
543 if (sccipher)
960e736a 544 sccipher->decrypt(pktin.data + st->cipherblk,
545 st->packetlen - st->cipherblk);
e5574168 546
7cca0d81 547#if 0
960e736a 548 debug(("Got packet len=%d pad=%d\r\n", st->len, st->pad));
549 for (st->i = 0; st->i < st->packetlen; st->i++)
550 debug((" %02x", (unsigned char)pktin.data[st->i]));
d39f364a 551 debug(("\r\n"));
7cca0d81 552#endif
d39f364a 553
e5574168 554 /*
555 * Check the MAC.
556 */
960e736a 557 if (scmac && !scmac->verify(pktin.data, st->len+4, st->incoming_sequence)) {
8d5de777 558 bombout(("Incorrect MAC received on packet"));
559 crReturn(0);
560 }
960e736a 561 st->incoming_sequence++; /* whether or not we MACed */
e5574168 562
4ba9b64b 563 /*
564 * Decompress packet payload.
565 */
566 {
567 unsigned char *newpayload;
568 int newlen;
569 if (sccomp && sccomp->decompress(pktin.data+5, pktin.length-5,
570 &newpayload, &newlen)) {
571 if (pktin.maxlen < newlen+5) {
572 pktin.maxlen = newlen+5;
dcbde236 573 pktin.data = (pktin.data == NULL ? smalloc(pktin.maxlen+APIEXTRA) :
574 srealloc(pktin.data, pktin.maxlen+APIEXTRA));
4ba9b64b 575 if (!pktin.data)
576 fatalbox("Out of memory");
577 }
578 pktin.length = 5 + newlen;
579 memcpy(pktin.data+5, newpayload, newlen);
580#if 0
581 debug(("Post-decompression payload:\r\n"));
582 for (st->i = 0; st->i < newlen; st->i++)
583 debug((" %02x", (unsigned char)pktin.data[5+st->i]));
584 debug(("\r\n"));
585#endif
586
dcbde236 587 sfree(newpayload);
4ba9b64b 588 }
589 }
590
e5574168 591 pktin.savedpos = 6;
592 pktin.type = pktin.data[5];
e5574168 593
7cca0d81 594 if (pktin.type == SSH2_MSG_IGNORE || pktin.type == SSH2_MSG_DEBUG)
595 goto next_packet; /* FIXME: print DEBUG message */
e5574168 596
597 crFinish(0);
598}
599
4ba9b64b 600static void ssh1_pktout_size(int len) {
374330e2 601 int pad, biglen;
602
603 len += 5; /* type and CRC */
604 pad = 8 - (len%8);
605 biglen = len + pad;
606
607 pktout.length = len-5;
608 if (pktout.maxlen < biglen) {
609 pktout.maxlen = biglen;
8f203108 610#ifdef MSCRYPTOAPI
fb09bf1c 611 /* Allocate enough buffer space for extra block
8f203108 612 * for MS CryptEncrypt() */
dcbde236 613 pktout.data = (pktout.data == NULL ? smalloc(biglen+12) :
614 srealloc(pktout.data, biglen+12));
8f203108 615#else
dcbde236 616 pktout.data = (pktout.data == NULL ? smalloc(biglen+4) :
617 srealloc(pktout.data, biglen+4));
8f203108 618#endif
374330e2 619 if (!pktout.data)
620 fatalbox("Out of memory");
621 }
4ba9b64b 622 pktout.body = pktout.data+4+pad+1;
623}
374330e2 624
4ba9b64b 625static void s_wrpkt_start(int type, int len) {
626 ssh1_pktout_size(len);
374330e2 627 pktout.type = type;
374330e2 628}
629
630static void s_wrpkt(void) {
631 int pad, len, biglen, i;
632 unsigned long crc;
633
4ba9b64b 634 pktout.body[-1] = pktout.type;
635
636 if (ssh1_compressing) {
637 unsigned char *compblk;
638 int complen;
639#if 0
640 debug(("Packet payload pre-compression:\n"));
641 for (i = -1; i < pktout.length; i++)
642 debug((" %02x", (unsigned char)pktout.body[i]));
643 debug(("\r\n"));
644#endif
645 zlib_compress_block(pktout.body-1, pktout.length+1,
646 &compblk, &complen);
647 ssh1_pktout_size(complen-1);
648 memcpy(pktout.body-1, compblk, complen);
dcbde236 649 sfree(compblk);
4ba9b64b 650#if 0
651 debug(("Packet payload post-compression:\n"));
652 for (i = -1; i < pktout.length; i++)
653 debug((" %02x", (unsigned char)pktout.body[i]));
654 debug(("\r\n"));
655#endif
656 }
657
374330e2 658 len = pktout.length + 5; /* type and CRC */
659 pad = 8 - (len%8);
660 biglen = len + pad;
661
374330e2 662 for (i=0; i<pad; i++)
663 pktout.data[i+4] = random_byte();
664 crc = crc32(pktout.data+4, biglen-4);
fb09bf1c 665 PUT_32BIT(pktout.data+biglen, crc);
666 PUT_32BIT(pktout.data, len);
374330e2 667
698a5108 668#if 0
669 debug(("Sending packet len=%d\r\n", biglen+4));
670 for (i = 0; i < biglen+4; i++)
671 debug((" %02x", (unsigned char)pktout.data[i]));
672 debug(("\r\n"));
673#endif
374330e2 674 if (cipher)
675 cipher->encrypt(pktout.data+4, biglen);
676
8df7a775 677 sk_write(s, pktout.data, biglen+4);
374330e2 678}
679
fb09bf1c 680/*
681 * Construct a packet with the specified contents and
682 * send it to the server.
683 */
684static void send_packet(int pkttype, ...)
685{
686 va_list args;
687 unsigned char *p, *argp, argchar;
688 unsigned long argint;
689 int pktlen, argtype, arglen;
7cca0d81 690 Bignum bn;
fb09bf1c 691
692 pktlen = 0;
693 va_start(args, pkttype);
694 while ((argtype = va_arg(args, int)) != PKT_END) {
695 switch (argtype) {
696 case PKT_INT:
697 (void) va_arg(args, int);
698 pktlen += 4;
699 break;
700 case PKT_CHAR:
701 (void) va_arg(args, char);
702 pktlen++;
703 break;
704 case PKT_DATA:
705 (void) va_arg(args, unsigned char *);
706 arglen = va_arg(args, int);
707 pktlen += arglen;
708 break;
709 case PKT_STR:
710 argp = va_arg(args, unsigned char *);
711 arglen = strlen(argp);
712 pktlen += 4 + arglen;
713 break;
7cca0d81 714 case PKT_BIGNUM:
715 bn = va_arg(args, Bignum);
5c58ad2d 716 pktlen += ssh1_bignum_length(bn);
7cca0d81 717 break;
fb09bf1c 718 default:
719 assert(0);
720 }
721 }
722 va_end(args);
723
724 s_wrpkt_start(pkttype, pktlen);
725 p = pktout.body;
726
727 va_start(args, pkttype);
728 while ((argtype = va_arg(args, int)) != PKT_END) {
729 switch (argtype) {
730 case PKT_INT:
731 argint = va_arg(args, int);
732 PUT_32BIT(p, argint);
733 p += 4;
734 break;
735 case PKT_CHAR:
736 argchar = va_arg(args, unsigned char);
737 *p = argchar;
738 p++;
739 break;
740 case PKT_DATA:
741 argp = va_arg(args, unsigned char *);
742 arglen = va_arg(args, int);
743 memcpy(p, argp, arglen);
744 p += arglen;
745 break;
746 case PKT_STR:
747 argp = va_arg(args, unsigned char *);
748 arglen = strlen(argp);
749 PUT_32BIT(p, arglen);
750 memcpy(p + 4, argp, arglen);
751 p += 4 + arglen;
752 break;
7cca0d81 753 case PKT_BIGNUM:
754 bn = va_arg(args, Bignum);
5c58ad2d 755 p += ssh1_write_bignum(p, bn);
7cca0d81 756 break;
fb09bf1c 757 }
758 }
759 va_end(args);
760
761 s_wrpkt();
762}
763
9697bfd2 764static int ssh_versioncmp(char *a, char *b) {
765 char *ae, *be;
766 unsigned long av, bv;
767
43aa02a7 768 av = strtoul(a, &ae, 10);
769 bv = strtoul(b, &be, 10);
9697bfd2 770 if (av != bv) return (av < bv ? -1 : +1);
771 if (*ae == '.') ae++;
772 if (*be == '.') be++;
43aa02a7 773 av = strtoul(ae, &ae, 10);
774 bv = strtoul(be, &be, 10);
9697bfd2 775 if (av != bv) return (av < bv ? -1 : +1);
776 return 0;
777}
778
e5574168 779
780/*
781 * Utility routine for putting an SSH-protocol `string' into a SHA
782 * state.
783 */
784#include <stdio.h>
75cab814 785static void sha_string(SHA_State *s, void *str, int len) {
e5574168 786 unsigned char lenblk[4];
e5574168 787 PUT_32BIT(lenblk, len);
e5574168 788 SHA_Bytes(s, lenblk, 4);
e5574168 789 SHA_Bytes(s, str, len);
790}
791
7cca0d81 792/*
793 * SSH2 packet construction functions.
794 */
75cab814 795static void ssh2_pkt_adddata(void *data, int len) {
7cca0d81 796 pktout.length += len;
797 if (pktout.maxlen < pktout.length) {
798 pktout.maxlen = pktout.length + 256;
dcbde236 799 pktout.data = (pktout.data == NULL ? smalloc(pktout.maxlen+APIEXTRA) :
800 srealloc(pktout.data, pktout.maxlen+APIEXTRA));
7cca0d81 801 if (!pktout.data)
802 fatalbox("Out of memory");
803 }
804 memcpy(pktout.data+pktout.length-len, data, len);
805}
75cab814 806static void ssh2_pkt_addbyte(unsigned char byte) {
7cca0d81 807 ssh2_pkt_adddata(&byte, 1);
808}
75cab814 809static void ssh2_pkt_init(int pkt_type) {
7cca0d81 810 pktout.length = 5;
811 ssh2_pkt_addbyte((unsigned char)pkt_type);
812}
75cab814 813static void ssh2_pkt_addbool(unsigned char value) {
7cca0d81 814 ssh2_pkt_adddata(&value, 1);
815}
75cab814 816static void ssh2_pkt_adduint32(unsigned long value) {
7cca0d81 817 unsigned char x[4];
818 PUT_32BIT(x, value);
819 ssh2_pkt_adddata(x, 4);
820}
75cab814 821static void ssh2_pkt_addstring_start(void) {
7cca0d81 822 ssh2_pkt_adduint32(0);
823 pktout.savedpos = pktout.length;
824}
75cab814 825static void ssh2_pkt_addstring_str(char *data) {
7cca0d81 826 ssh2_pkt_adddata(data, strlen(data));
827 PUT_32BIT(pktout.data + pktout.savedpos - 4,
828 pktout.length - pktout.savedpos);
829}
75cab814 830static void ssh2_pkt_addstring_data(char *data, int len) {
7cca0d81 831 ssh2_pkt_adddata(data, len);
832 PUT_32BIT(pktout.data + pktout.savedpos - 4,
833 pktout.length - pktout.savedpos);
834}
75cab814 835static void ssh2_pkt_addstring(char *data) {
7cca0d81 836 ssh2_pkt_addstring_start();
837 ssh2_pkt_addstring_str(data);
838}
75cab814 839static char *ssh2_mpint_fmt(Bignum b, int *len) {
7cca0d81 840 unsigned char *p;
841 int i, n = b[0];
dcbde236 842 p = smalloc(n * 2 + 1);
7cca0d81 843 if (!p)
844 fatalbox("out of memory");
845 p[0] = 0;
846 for (i = 0; i < n; i++) {
847 p[i*2+1] = (b[n-i] >> 8) & 0xFF;
848 p[i*2+2] = (b[n-i] ) & 0xFF;
849 }
850 i = 0;
851 while (p[i] == 0 && (p[i+1] & 0x80) == 0)
852 i++;
853 memmove(p, p+i, n*2+1-i);
854 *len = n*2+1-i;
855 return p;
856}
75cab814 857static void ssh2_pkt_addmp(Bignum b) {
7cca0d81 858 unsigned char *p;
859 int len;
860 p = ssh2_mpint_fmt(b, &len);
861 ssh2_pkt_addstring_start();
862 ssh2_pkt_addstring_data(p, len);
dcbde236 863 sfree(p);
7cca0d81 864}
75cab814 865static void ssh2_pkt_send(void) {
7cca0d81 866 int cipherblk, maclen, padding, i;
867 static unsigned long outgoing_sequence = 0;
868
869 /*
4ba9b64b 870 * Compress packet payload.
871 */
872#if 0
873 debug(("Pre-compression payload:\r\n"));
874 for (i = 5; i < pktout.length; i++)
875 debug((" %02x", (unsigned char)pktout.data[i]));
876 debug(("\r\n"));
877#endif
878 {
879 unsigned char *newpayload;
880 int newlen;
881 if (cscomp && cscomp->compress(pktout.data+5, pktout.length-5,
882 &newpayload, &newlen)) {
883 pktout.length = 5;
884 ssh2_pkt_adddata(newpayload, newlen);
dcbde236 885 sfree(newpayload);
4ba9b64b 886 }
887 }
888
889 /*
7cca0d81 890 * Add padding. At least four bytes, and must also bring total
891 * length (minus MAC) up to a multiple of the block size.
892 */
893 cipherblk = cipher ? cipher->blksize : 8; /* block size */
894 cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */
895 padding = 4;
896 padding += (cipherblk - (pktout.length + padding) % cipherblk) % cipherblk;
897 pktout.data[4] = padding;
898 for (i = 0; i < padding; i++)
899 pktout.data[pktout.length + i] = random_byte();
900 PUT_32BIT(pktout.data, pktout.length + padding - 4);
901 if (csmac)
902 csmac->generate(pktout.data, pktout.length + padding,
903 outgoing_sequence);
904 outgoing_sequence++; /* whether or not we MACed */
905
906#if 0
907 debug(("Sending packet len=%d\r\n", pktout.length+padding));
908 for (i = 0; i < pktout.length+padding; i++)
909 debug((" %02x", (unsigned char)pktout.data[i]));
910 debug(("\r\n"));
911#endif
912
913 if (cscipher)
914 cscipher->encrypt(pktout.data, pktout.length + padding);
915 maclen = csmac ? csmac->len : 0;
916
8df7a775 917 sk_write(s, pktout.data, pktout.length + padding + maclen);
7cca0d81 918}
919
920#if 0
921void bndebug(char *string, Bignum b) {
922 unsigned char *p;
923 int i, len;
924 p = ssh2_mpint_fmt(b, &len);
925 debug(("%s", string));
926 for (i = 0; i < len; i++)
927 debug((" %02x", p[i]));
928 debug(("\r\n"));
dcbde236 929 sfree(p);
7cca0d81 930}
931#endif
932
75cab814 933static void sha_mpint(SHA_State *s, Bignum b) {
7cca0d81 934 unsigned char *p;
935 int len;
936 p = ssh2_mpint_fmt(b, &len);
937 sha_string(s, p, len);
dcbde236 938 sfree(p);
7cca0d81 939}
940
941/*
942 * SSH2 packet decode functions.
943 */
75cab814 944static unsigned long ssh2_pkt_getuint32(void) {
7cca0d81 945 unsigned long value;
946 if (pktin.length - pktin.savedpos < 4)
947 return 0; /* arrgh, no way to decline (FIXME?) */
948 value = GET_32BIT(pktin.data+pktin.savedpos);
949 pktin.savedpos += 4;
950 return value;
951}
75cab814 952static void ssh2_pkt_getstring(char **p, int *length) {
7cca0d81 953 *p = NULL;
954 if (pktin.length - pktin.savedpos < 4)
955 return;
956 *length = GET_32BIT(pktin.data+pktin.savedpos);
957 pktin.savedpos += 4;
958 if (pktin.length - pktin.savedpos < *length)
959 return;
960 *p = pktin.data+pktin.savedpos;
961 pktin.savedpos += *length;
962}
75cab814 963static Bignum ssh2_pkt_getmp(void) {
7cca0d81 964 char *p;
965 int i, j, length;
966 Bignum b;
967
968 ssh2_pkt_getstring(&p, &length);
969 if (!p)
970 return NULL;
8d5de777 971 if (p[0] & 0x80) {
972 bombout(("internal error: Can't handle negative mpints"));
973 return NULL;
974 }
7cca0d81 975 b = newbn((length+1)/2);
976 for (i = 0; i < length; i++) {
977 j = length - 1 - i;
978 if (j & 1)
979 b[j/2+1] |= ((unsigned char)p[i]) << 8;
980 else
981 b[j/2+1] |= ((unsigned char)p[i]);
982 }
6b4e00ee 983 while (b[0] > 1 && b[b[0]] == 0) b[0]--;
7cca0d81 984 return b;
985}
986
8df7a775 987static int do_ssh_init(unsigned char c) {
988 static char *vsp;
989 static char version[10];
990 static char vstring[80];
991 static char vlog[sizeof(vstring)+20];
992 static int i;
374330e2 993
8df7a775 994 crBegin;
995
996 /* Search for the string "SSH-" in the input. */
374330e2 997 i = 0;
8df7a775 998 while (1) {
999 static const int transS[] = { 1, 2, 2, 1 };
1000 static const int transH[] = { 0, 0, 3, 0 };
1001 static const int transminus[] = { 0, 0, 0, -1 };
1002 if (c == 'S') i = transS[i];
1003 else if (c == 'H') i = transH[i];
1004 else if (c == '-') i = transminus[i];
374330e2 1005 else i = 0;
8df7a775 1006 if (i < 0)
1007 break;
1008 crReturn(1); /* get another character */
374330e2 1009 }
8df7a775 1010
c5e9c988 1011 strcpy(vstring, "SSH-");
1012 vsp = vstring+4;
374330e2 1013 i = 0;
1014 while (1) {
8df7a775 1015 crReturn(1); /* get another char */
c5e9c988 1016 if (vsp < vstring+sizeof(vstring)-1)
1017 *vsp++ = c;
374330e2 1018 if (i >= 0) {
1019 if (c == '-') {
1020 version[i] = '\0';
1021 i = -1;
1022 } else if (i < sizeof(version)-1)
1023 version[i++] = c;
1024 }
1025 else if (c == '\n')
1026 break;
1027 }
1028
db7d555c 1029 ssh_agentfwd_enabled = FALSE;
960e736a 1030 rdpkt2_state.incoming_sequence = 0;
1031
c5e9c988 1032 *vsp = 0;
1033 sprintf(vlog, "Server version: %s", vstring);
1034 vlog[strcspn(vlog, "\r\n")] = '\0';
1035 logevent(vlog);
1036
adf799dd 1037 /*
1038 * Server version "1.99" means we can choose whether we use v1
1039 * or v2 protocol. Choice is based on cfg.sshprot.
1040 */
1041 if (ssh_versioncmp(version, cfg.sshprot == 1 ? "2.0" : "1.99") >= 0) {
e5574168 1042 /*
1043 * This is a v2 server. Begin v2 protocol.
1044 */
1045 char *verstring = "SSH-2.0-PuTTY";
1046 SHA_Init(&exhash);
1047 /*
1048 * Hash our version string and their version string.
1049 */
1050 sha_string(&exhash, verstring, strlen(verstring));
1051 sha_string(&exhash, vstring, strcspn(vstring, "\r\n"));
1052 sprintf(vstring, "%s\n", verstring);
1053 sprintf(vlog, "We claim version: %s", verstring);
1054 logevent(vlog);
1055 logevent("Using SSH protocol version 2");
8df7a775 1056 sk_write(s, vstring, strlen(vstring));
e5574168 1057 ssh_protocol = ssh2_protocol;
6abbf9e3 1058 ssh_version = 2;
e5574168 1059 s_rdpkt = ssh2_rdpkt;
1060 } else {
1061 /*
1062 * This is a v1 server. Begin v1 protocol.
1063 */
1064 sprintf(vstring, "SSH-%s-PuTTY\n",
1065 (ssh_versioncmp(version, "1.5") <= 0 ? version : "1.5"));
1066 sprintf(vlog, "We claim version: %s", vstring);
1067 vlog[strcspn(vlog, "\r\n")] = '\0';
1068 logevent(vlog);
1069 logevent("Using SSH protocol version 1");
8df7a775 1070 sk_write(s, vstring, strlen(vstring));
e5574168 1071 ssh_protocol = ssh1_protocol;
6abbf9e3 1072 ssh_version = 1;
e5574168 1073 s_rdpkt = ssh1_rdpkt;
1074 }
8df7a775 1075
1076 crFinish(0);
1077}
1078
1079static void ssh_gotdata(unsigned char *data, int datalen)
1080{
1081 crBegin;
1082
1083 /*
1084 * To begin with, feed the characters one by one to the
1085 * protocol initialisation / selection function do_ssh_init().
1086 * When that returns 0, we're done with the initial greeting
1087 * exchange and can move on to packet discipline.
1088 */
1089 while (1) {
1090 int ret;
1091 if (datalen == 0)
1092 crReturnV; /* more data please */
1093 ret = do_ssh_init(*data);
1094 data++; datalen--;
1095 if (ret == 0)
1096 break;
1097 }
1098
1099 /*
1100 * We emerge from that loop when the initial negotiation is
1101 * over and we have selected an s_rdpkt function. Now pass
1102 * everything to s_rdpkt, and then pass the resulting packets
1103 * to the proper protocol handler.
1104 */
1105 if (datalen == 0)
1106 crReturnV;
1107 while (1) {
1108 while (datalen > 0) {
1109 if ( s_rdpkt(&data, &datalen) == 0 ) {
1110 ssh_protocol(NULL, 0, 1);
1111 if (ssh_state == SSH_STATE_CLOSED) {
1112 return;
1113 }
1114 }
1115 }
1116 crReturnV;
1117 }
1118 crFinishV;
1119}
1120
340cf649 1121static int ssh_receive(Socket skt, int urgent, char *data, int len) {
8df7a775 1122 if (!len) {
1123 /* Connection has closed. */
1124 sk_close(s);
1125 s = NULL;
1126 return 0;
1127 }
1128 ssh_gotdata (data, len);
3257deae 1129 if (ssh_state == SSH_STATE_CLOSED) {
1130 if (s) {
1131 sk_close(s);
1132 s = NULL;
1133 }
1134 return 0;
1135 }
fef97f43 1136 return 1;
374330e2 1137}
1138
fb09bf1c 1139/*
8df7a775 1140 * Connect to specified host and port.
1141 * Returns an error message, or NULL on success.
1142 * Also places the canonical host name into `realhost'.
1143 */
1144static char *connect_to_host(char *host, int port, char **realhost)
1145{
1146 SockAddr addr;
1147 char *err;
1148#ifdef FWHACK
1149 char *FWhost;
1150 int FWport;
1151#endif
1152
dcbde236 1153 savedhost = smalloc(1+strlen(host));
8df7a775 1154 if (!savedhost)
1155 fatalbox("Out of memory");
1156 strcpy(savedhost, host);
1157
1158 if (port < 0)
1159 port = 22; /* default ssh port */
1160 savedport = port;
1161
1162#ifdef FWHACK
1163 FWhost = host;
1164 FWport = port;
1165 host = FWSTR;
1166 port = 23;
1167#endif
1168
1169 /*
1170 * Try to find host.
1171 */
1172 addr = sk_namelookup(host, realhost);
1173 if ( (err = sk_addr_error(addr)) )
1174 return err;
1175
1176#ifdef FWHACK
1177 *realhost = FWhost;
1178#endif
1179
1180 /*
1181 * Open socket.
1182 */
1183 s = sk_new(addr, port, ssh_receive);
1184 if ( (err = sk_socket_error(s)) )
1185 return err;
1186
1187#ifdef FWHACK
1188 sk_write(s, "connect ", 8);
1189 sk_write(s, FWhost, strlen(FWhost));
1190 {
1191 char buf[20];
1192 sprintf(buf, " %d\n", FWport);
1193 sk_write(s, buf, strlen(buf));
1194 }
1195#endif
1196
1197 return NULL;
1198}
1199
1200/*
fb09bf1c 1201 * Handle the key exchange and user authentication phases.
1202 */
e5574168 1203static int do_ssh1_login(unsigned char *in, int inlen, int ispkt)
fb09bf1c 1204{
374330e2 1205 int i, j, len;
374330e2 1206 unsigned char *rsabuf, *keystr1, *keystr2;
1207 unsigned char cookie[8];
1208 struct RSAKey servkey, hostkey;
1209 struct MD5Context md5c;
ccbfb941 1210 static unsigned long supported_ciphers_mask, supported_auths_mask;
7cca0d81 1211 static int tried_publickey;
1212 static unsigned char session_id[16];
bea1ef5f 1213 int cipher_type;
b585ec46 1214 static char username[100];
374330e2 1215
374330e2 1216 crBegin;
1217
fb09bf1c 1218 if (!ispkt) crWaitUntil(ispkt);
374330e2 1219
8d5de777 1220 if (pktin.type != SSH1_SMSG_PUBLIC_KEY) {
1221 bombout(("Public key packet not received"));
1222 crReturn(0);
1223 }
374330e2 1224
c5e9c988 1225 logevent("Received public keys");
374330e2 1226
c5e9c988 1227 memcpy(cookie, pktin.body, 8);
374330e2 1228
7cca0d81 1229 i = makekey(pktin.body+8, &servkey, &keystr1, 0);
1230 j = makekey(pktin.body+8+i, &hostkey, &keystr2, 0);
374330e2 1231
c5e9c988 1232 /*
1c2a93c4 1233 * Log the host key fingerprint.
c5e9c988 1234 */
c5e9c988 1235 {
1236 char logmsg[80];
1c2a93c4 1237 logevent("Host key fingerprint is:");
c5e9c988 1238 strcpy(logmsg, " ");
1c2a93c4 1239 hostkey.comment = NULL;
1240 rsa_fingerprint(logmsg+strlen(logmsg), sizeof(logmsg)-strlen(logmsg),
1241 &hostkey);
c5e9c988 1242 logevent(logmsg);
1243 }
1244
fb09bf1c 1245 supported_ciphers_mask = GET_32BIT(pktin.body+12+i+j);
1246 supported_auths_mask = GET_32BIT(pktin.body+16+i+j);
bea1ef5f 1247
c5e9c988 1248 MD5Init(&md5c);
374330e2 1249 MD5Update(&md5c, keystr2, hostkey.bytes);
1250 MD5Update(&md5c, keystr1, servkey.bytes);
1251 MD5Update(&md5c, pktin.body, 8);
374330e2 1252 MD5Final(session_id, &md5c);
1253
1254 for (i=0; i<32; i++)
1255 session_key[i] = random_byte();
1256
1257 len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes);
1258
dcbde236 1259 rsabuf = smalloc(len);
374330e2 1260 if (!rsabuf)
1261 fatalbox("Out of memory");
1262
89ee5268 1263 /*
1264 * Verify the host key.
1265 */
1266 {
1267 /*
1268 * First format the key into a string.
1269 */
1270 int len = rsastr_len(&hostkey);
d5859615 1271 char fingerprint[100];
dcbde236 1272 char *keystr = smalloc(len);
89ee5268 1273 if (!keystr)
1274 fatalbox("Out of memory");
1275 rsastr_fmt(keystr, &hostkey);
d5859615 1276 rsa_fingerprint(fingerprint, sizeof(fingerprint), &hostkey);
d4857987 1277 verify_ssh_host_key(savedhost, savedport, "rsa", keystr, fingerprint);
dcbde236 1278 sfree(keystr);
89ee5268 1279 }
374330e2 1280
1281 for (i=0; i<32; i++) {
1282 rsabuf[i] = session_key[i];
1283 if (i < 16)
1284 rsabuf[i] ^= session_id[i];
1285 }
1286
1287 if (hostkey.bytes > servkey.bytes) {
1288 rsaencrypt(rsabuf, 32, &servkey);
1289 rsaencrypt(rsabuf, servkey.bytes, &hostkey);
1290 } else {
1291 rsaencrypt(rsabuf, 32, &hostkey);
1292 rsaencrypt(rsabuf, hostkey.bytes, &servkey);
1293 }
1294
c5e9c988 1295 logevent("Encrypted session key");
1296
bea1ef5f 1297 cipher_type = cfg.cipher == CIPHER_BLOWFISH ? SSH_CIPHER_BLOWFISH :
9697bfd2 1298 cfg.cipher == CIPHER_DES ? SSH_CIPHER_DES :
bea1ef5f 1299 SSH_CIPHER_3DES;
1300 if ((supported_ciphers_mask & (1 << cipher_type)) == 0) {
1301 c_write("Selected cipher not supported, falling back to 3DES\r\n", 53);
1302 cipher_type = SSH_CIPHER_3DES;
1303 }
c5e9c988 1304 switch (cipher_type) {
1305 case SSH_CIPHER_3DES: logevent("Using 3DES encryption"); break;
1306 case SSH_CIPHER_DES: logevent("Using single-DES encryption"); break;
1307 case SSH_CIPHER_BLOWFISH: logevent("Using Blowfish encryption"); break;
1308 }
bea1ef5f 1309
e5574168 1310 send_packet(SSH1_CMSG_SESSION_KEY,
fb09bf1c 1311 PKT_CHAR, cipher_type,
1312 PKT_DATA, cookie, 8,
1313 PKT_CHAR, (len*8) >> 8, PKT_CHAR, (len*8) & 0xFF,
1314 PKT_DATA, rsabuf, len,
1315 PKT_INT, 0,
1316 PKT_END);
1317
c5e9c988 1318 logevent("Trying to enable encryption...");
374330e2 1319
dcbde236 1320 sfree(rsabuf);
374330e2 1321
5e8358ad 1322 cipher = cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 :
9697bfd2 1323 cipher_type == SSH_CIPHER_DES ? &ssh_des :
bea1ef5f 1324 &ssh_3des;
374330e2 1325 cipher->sesskey(session_key);
1326
fb09bf1c 1327 crWaitUntil(ispkt);
374330e2 1328
8d5de777 1329 if (pktin.type != SSH1_SMSG_SUCCESS) {
1330 bombout(("Encryption not successfully enabled"));
1331 crReturn(0);
1332 }
374330e2 1333
c5e9c988 1334 logevent("Successfully started encryption");
1335
374330e2 1336 fflush(stdout);
1337 {
374330e2 1338 static int pos = 0;
1339 static char c;
67779be7 1340 if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
374330e2 1341 c_write("login as: ", 10);
67779be7 1342 ssh_send_ok = 1;
374330e2 1343 while (pos >= 0) {
fb09bf1c 1344 crWaitUntil(!ispkt);
374330e2 1345 while (inlen--) switch (c = *in++) {
1346 case 10: case 13:
1347 username[pos] = 0;
1348 pos = -1;
1349 break;
1350 case 8: case 127:
1351 if (pos > 0) {
1352 c_write("\b \b", 3);
1353 pos--;
1354 }
1355 break;
1356 case 21: case 27:
1357 while (pos > 0) {
1358 c_write("\b \b", 3);
1359 pos--;
1360 }
1361 break;
1362 case 3: case 4:
1363 random_save_seed();
1364 exit(0);
1365 break;
1366 default:
40d24aa6 1367 if (((c >= ' ' && c <= '~') ||
1368 ((unsigned char)c >= 160)) && pos < 40) {
374330e2 1369 username[pos++] = c;
1370 c_write(&c, 1);
1371 }
1372 break;
1373 }
1374 }
1375 c_write("\r\n", 2);
1376 username[strcspn(username, "\n\r")] = '\0';
1377 } else {
374330e2 1378 strncpy(username, cfg.username, 99);
1379 username[99] = '\0';
374330e2 1380 }
fb09bf1c 1381
e5574168 1382 send_packet(SSH1_CMSG_USER, PKT_STR, username, PKT_END);
c5e9c988 1383 {
3c8e959b 1384 char userlog[22+sizeof(username)];
c5e9c988 1385 sprintf(userlog, "Sent username \"%s\"", username);
1386 logevent(userlog);
3c8e959b 1387 if (flags & FLAG_INTERACTIVE &&
1388 (!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) {
1389 strcat(userlog, "\r\n");
1390 c_write(userlog, strlen(userlog));
1391 }
c5e9c988 1392 }
374330e2 1393 }
1394
fb09bf1c 1395 crWaitUntil(ispkt);
374330e2 1396
7cca0d81 1397 tried_publickey = 0;
1398
e5574168 1399 while (pktin.type == SSH1_SMSG_FAILURE) {
374330e2 1400 static char password[100];
a52f067e 1401 static char prompt[200];
374330e2 1402 static int pos;
1403 static char c;
ccbfb941 1404 static int pwpkt_type;
ccbfb941 1405 /*
1406 * Show password prompt, having first obtained it via a TIS
18515c51 1407 * or CryptoCard exchange if we're doing TIS or CryptoCard
1408 * authentication.
ccbfb941 1409 */
e5574168 1410 pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
5c58ad2d 1411 if (agent_exists()) {
1412 /*
1413 * Attempt RSA authentication using Pageant.
1414 */
1415 static unsigned char request[5], *response, *p;
1416 static int responselen;
1417 static int i, nkeys;
1418 static int authed = FALSE;
1419 void *r;
1420
1421 logevent("Pageant is running. Requesting keys.");
1422
1423 /* Request the keys held by the agent. */
1424 PUT_32BIT(request, 1);
1425 request[4] = SSH_AGENTC_REQUEST_RSA_IDENTITIES;
1426 agent_query(request, 5, &r, &responselen);
1427 response = (unsigned char *)r;
1428 if (response) {
1429 p = response + 5;
1430 nkeys = GET_32BIT(p); p += 4;
1431 { char buf[64]; sprintf(buf, "Pageant has %d keys", nkeys);
1432 logevent(buf); }
1433 for (i = 0; i < nkeys; i++) {
1434 static struct RSAKey key;
1435 static Bignum challenge;
b8bb811a 1436 static char *commentp;
1437 static int commentlen;
5c58ad2d 1438
1439 { char buf[64]; sprintf(buf, "Trying Pageant key #%d", i);
1440 logevent(buf); }
1441 p += 4;
1442 p += ssh1_read_bignum(p, &key.exponent);
1443 p += ssh1_read_bignum(p, &key.modulus);
b8bb811a 1444 commentlen = GET_32BIT(p); p += 4;
1445 commentp = p; p += commentlen;
5c58ad2d 1446 send_packet(SSH1_CMSG_AUTH_RSA,
1447 PKT_BIGNUM, key.modulus, PKT_END);
1448 crWaitUntil(ispkt);
1449 if (pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
1450 logevent("Key refused");
1451 continue;
1452 }
1453 logevent("Received RSA challenge");
1454 ssh1_read_bignum(pktin.body, &challenge);
1455 {
1456 char *agentreq, *q, *ret;
1457 int len, retlen;
1458 len = 1 + 4; /* message type, bit count */
1459 len += ssh1_bignum_length(key.exponent);
1460 len += ssh1_bignum_length(key.modulus);
1461 len += ssh1_bignum_length(challenge);
1462 len += 16; /* session id */
1463 len += 4; /* response format */
dcbde236 1464 agentreq = smalloc(4 + len);
5c58ad2d 1465 PUT_32BIT(agentreq, len);
1466 q = agentreq + 4;
1467 *q++ = SSH_AGENTC_RSA_CHALLENGE;
1468 PUT_32BIT(q, ssh1_bignum_bitcount(key.modulus));
1469 q += 4;
1470 q += ssh1_write_bignum(q, key.exponent);
1471 q += ssh1_write_bignum(q, key.modulus);
1472 q += ssh1_write_bignum(q, challenge);
1473 memcpy(q, session_id, 16); q += 16;
1474 PUT_32BIT(q, 1); /* response format */
1475 agent_query(agentreq, len+4, &ret, &retlen);
dcbde236 1476 sfree(agentreq);
5c58ad2d 1477 if (ret) {
1478 if (ret[4] == SSH_AGENT_RSA_RESPONSE) {
1479 logevent("Sending Pageant's response");
1480 send_packet(SSH1_CMSG_AUTH_RSA_RESPONSE,
1481 PKT_DATA, ret+5, 16, PKT_END);
dcbde236 1482 sfree(ret);
5c58ad2d 1483 crWaitUntil(ispkt);
1484 if (pktin.type == SSH1_SMSG_SUCCESS) {
1485 logevent("Pageant's response accepted");
c4fa2fce 1486 if (flags & FLAG_VERBOSE) {
1487 c_write("Authenticated using RSA key \"",
1488 29);
1489 c_write(commentp, commentlen);
1490 c_write("\" from agent\r\n", 14);
1491 }
5c58ad2d 1492 authed = TRUE;
1493 } else
1494 logevent("Pageant's response not accepted");
1495 } else {
1496 logevent("Pageant failed to answer challenge");
dcbde236 1497 sfree(ret);
5c58ad2d 1498 }
1499 } else {
1500 logevent("No reply received from Pageant");
1501 }
1502 }
1503 freebn(key.exponent);
1504 freebn(key.modulus);
1505 freebn(challenge);
1506 if (authed)
1507 break;
1508 }
1509 }
1510 if (authed)
1511 break;
1512 }
7cca0d81 1513 if (*cfg.keyfile && !tried_publickey)
1514 pwpkt_type = SSH1_CMSG_AUTH_RSA;
fb09bf1c 1515
a52f067e 1516 if (pktin.type == SSH1_SMSG_FAILURE &&
1517 cfg.try_tis_auth &&
1518 (supported_auths_mask & (1<<SSH1_AUTH_TIS))) {
1519 pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
1520 logevent("Requested TIS authentication");
1521 send_packet(SSH1_CMSG_AUTH_TIS, PKT_END);
1522 crWaitUntil(ispkt);
1523 if (pktin.type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
1524 logevent("TIS authentication declined");
1525 if (flags & FLAG_INTERACTIVE)
1526 c_write("TIS authentication refused.\r\n", 29);
1527 } else {
1528 int challengelen = ((pktin.body[0] << 24) |
1529 (pktin.body[1] << 16) |
1530 (pktin.body[2] << 8) |
1531 (pktin.body[3]));
1532 logevent("Received TIS challenge");
1533 if (challengelen > sizeof(prompt)-1)
1534 challengelen = sizeof(prompt)-1; /* prevent overrun */
1535 memcpy(prompt, pktin.body+4, challengelen);
1536 prompt[challengelen] = '\0';
1537 }
1538 }
1539 if (pktin.type == SSH1_SMSG_FAILURE &&
1540 cfg.try_tis_auth &&
1541 (supported_auths_mask & (1<<SSH1_AUTH_CCARD))) {
1542 pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE;
1543 logevent("Requested CryptoCard authentication");
1544 send_packet(SSH1_CMSG_AUTH_CCARD, PKT_END);
1545 crWaitUntil(ispkt);
1546 if (pktin.type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
1547 logevent("CryptoCard authentication declined");
1548 c_write("CryptoCard authentication refused.\r\n", 29);
1549 } else {
1550 int challengelen = ((pktin.body[0] << 24) |
1551 (pktin.body[1] << 16) |
1552 (pktin.body[2] << 8) |
1553 (pktin.body[3]));
1554 logevent("Received CryptoCard challenge");
1555 if (challengelen > sizeof(prompt)-1)
1556 challengelen = sizeof(prompt)-1; /* prevent overrun */
1557 memcpy(prompt, pktin.body+4, challengelen);
1558 strncpy(prompt + challengelen, "\r\nResponse : ",
1559 sizeof(prompt)-challengelen);
1560 prompt[sizeof(prompt)-1] = '\0';
1561 }
1562 }
1563 if (pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
1564 sprintf(prompt, "%.90s@%.90s's password: ",
b585ec46 1565 username, savedhost);
a52f067e 1566 }
1567 if (pwpkt_type == SSH1_CMSG_AUTH_RSA) {
1568 char *comment = NULL;
1569 if (flags & FLAG_VERBOSE)
1570 c_write("Trying public key authentication.\r\n", 35);
1571 if (!rsakey_encrypted(cfg.keyfile, &comment)) {
1572 if (flags & FLAG_VERBOSE)
1573 c_write("No passphrase required.\r\n", 25);
1574 goto tryauth;
1575 }
1576 sprintf(prompt, "Passphrase for key \"%.100s\": ", comment);
dcbde236 1577 sfree(comment);
a52f067e 1578 }
1579
d8426c54 1580 if (ssh_get_password) {
85ee8208 1581 if (!ssh_get_password(prompt, password, sizeof(password))) {
1582 /*
1583 * get_password failed to get a password (for
1584 * example because one was supplied on the command
1585 * line which has already failed to work).
1586 * Terminate.
1587 */
1588 logevent("No more passwords to try");
1589 ssh_state = SSH_STATE_CLOSED;
1590 crReturn(1);
1591 }
fb09bf1c 1592 } else {
a52f067e 1593 c_write(prompt, strlen(prompt));
7cca0d81 1594 pos = 0;
67779be7 1595 ssh_send_ok = 1;
7cca0d81 1596 while (pos >= 0) {
1597 crWaitUntil(!ispkt);
1598 while (inlen--) switch (c = *in++) {
1599 case 10: case 13:
1600 password[pos] = 0;
1601 pos = -1;
1602 break;
1603 case 8: case 127:
1604 if (pos > 0)
1605 pos--;
1606 break;
1607 case 21: case 27:
1608 pos = 0;
1609 break;
1610 case 3: case 4:
1611 random_save_seed();
1612 exit(0);
1613 break;
1614 default:
1615 if (((c >= ' ' && c <= '~') ||
1616 ((unsigned char)c >= 160)) && pos < sizeof(password))
1617 password[pos++] = c;
1618 break;
1619 }
1620 }
1621 c_write("\r\n", 2);
a52f067e 1622 }
fb09bf1c 1623
7cca0d81 1624 tryauth:
1625 if (pwpkt_type == SSH1_CMSG_AUTH_RSA) {
1626 /*
1627 * Try public key authentication with the specified
1628 * key file.
1629 */
1630 static struct RSAKey pubkey;
1631 static Bignum challenge, response;
1632 static int i;
1633 static unsigned char buffer[32];
1634
1635 tried_publickey = 1;
6e522441 1636 i = loadrsakey(cfg.keyfile, &pubkey, NULL, password);
7cca0d81 1637 if (i == 0) {
1638 c_write("Couldn't load public key from ", 30);
1639 c_write(cfg.keyfile, strlen(cfg.keyfile));
1640 c_write(".\r\n", 3);
1641 continue; /* go and try password */
1642 }
1643 if (i == -1) {
1644 c_write("Wrong passphrase.\r\n", 19);
1645 tried_publickey = 0;
1646 continue; /* try again */
1647 }
1648
1649 /*
1650 * Send a public key attempt.
1651 */
1652 send_packet(SSH1_CMSG_AUTH_RSA,
1653 PKT_BIGNUM, pubkey.modulus, PKT_END);
1654
1655 crWaitUntil(ispkt);
1656 if (pktin.type == SSH1_SMSG_FAILURE) {
a52f067e 1657 c_write("Server refused our public key.\r\n", 32);
7cca0d81 1658 continue; /* go and try password */
1659 }
8d5de777 1660 if (pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
1661 bombout(("Bizarre response to offer of public key"));
1662 crReturn(0);
1663 }
7cca0d81 1664 ssh1_read_bignum(pktin.body, &challenge);
1665 response = rsadecrypt(challenge, &pubkey);
1666 freebn(pubkey.private_exponent); /* burn the evidence */
1667
1668 for (i = 0; i < 32; i += 2) {
1669 buffer[i] = response[16-i/2] >> 8;
1670 buffer[i+1] = response[16-i/2] & 0xFF;
1671 }
1672
1673 MD5Init(&md5c);
1674 MD5Update(&md5c, buffer, 32);
1675 MD5Update(&md5c, session_id, 16);
1676 MD5Final(buffer, &md5c);
1677
1678 send_packet(SSH1_CMSG_AUTH_RSA_RESPONSE,
1679 PKT_DATA, buffer, 16, PKT_END);
1680
1681 crWaitUntil(ispkt);
1682 if (pktin.type == SSH1_SMSG_FAILURE) {
4017be6d 1683 if (flags & FLAG_VERBOSE)
1684 c_write("Failed to authenticate with our public key.\r\n",
1685 45);
7cca0d81 1686 continue; /* go and try password */
1687 } else if (pktin.type != SSH1_SMSG_SUCCESS) {
8d5de777 1688 bombout(("Bizarre response to RSA authentication response"));
1689 crReturn(0);
7cca0d81 1690 }
1691
1692 break; /* we're through! */
1693 } else {
1694 send_packet(pwpkt_type, PKT_STR, password, PKT_END);
1695 }
c5e9c988 1696 logevent("Sent password");
374330e2 1697 memset(password, 0, strlen(password));
fb09bf1c 1698 crWaitUntil(ispkt);
e5574168 1699 if (pktin.type == SSH1_SMSG_FAILURE) {
4017be6d 1700 if (flags & FLAG_VERBOSE)
1701 c_write("Access denied\r\n", 15);
c5e9c988 1702 logevent("Authentication refused");
e5574168 1703 } else if (pktin.type == SSH1_MSG_DISCONNECT) {
fb09bf1c 1704 logevent("Received disconnect request");
85ee8208 1705 ssh_state = SSH_STATE_CLOSED;
1706 crReturn(1);
e5574168 1707 } else if (pktin.type != SSH1_SMSG_SUCCESS) {
8d5de777 1708 bombout(("Strange packet received, type %d", pktin.type));
1709 crReturn(0);
374330e2 1710 }
1711 }
1712
c5e9c988 1713 logevent("Authentication successful");
1714
fb09bf1c 1715 crFinish(1);
1716}
1717
e5574168 1718static void ssh1_protocol(unsigned char *in, int inlen, int ispkt) {
fb09bf1c 1719 crBegin;
1720
1721 random_init();
1722
e5574168 1723 while (!do_ssh1_login(in, inlen, ispkt)) {
fb09bf1c 1724 crReturnV;
85ee8208 1725 }
1726 if (ssh_state == SSH_STATE_CLOSED)
1727 crReturnV;
fb09bf1c 1728
979310f1 1729 if (cfg.agentfwd && agent_exists()) {
dacbd0e8 1730 logevent("Requesting agent forwarding");
1731 send_packet(SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END);
1732 do { crReturnV; } while (!ispkt);
1733 if (pktin.type != SSH1_SMSG_SUCCESS && pktin.type != SSH1_SMSG_FAILURE) {
8d5de777 1734 bombout(("Protocol confusion"));
1735 crReturnV;
dacbd0e8 1736 } else if (pktin.type == SSH1_SMSG_FAILURE) {
1737 logevent("Agent forwarding refused");
db7d555c 1738 } else {
dacbd0e8 1739 logevent("Agent forwarding enabled");
db7d555c 1740 ssh_agentfwd_enabled = TRUE;
1741 }
dacbd0e8 1742 }
1743
fef97f43 1744 if (!cfg.nopty) {
e5574168 1745 send_packet(SSH1_CMSG_REQUEST_PTY,
fb09bf1c 1746 PKT_STR, cfg.termtype,
1747 PKT_INT, rows, PKT_INT, cols,
1748 PKT_INT, 0, PKT_INT, 0,
1749 PKT_CHAR, 0,
1750 PKT_END);
fef97f43 1751 ssh_state = SSH_STATE_INTERMED;
1752 do { crReturnV; } while (!ispkt);
e5574168 1753 if (pktin.type != SSH1_SMSG_SUCCESS && pktin.type != SSH1_SMSG_FAILURE) {
8d5de777 1754 bombout(("Protocol confusion"));
1755 crReturnV;
e5574168 1756 } else if (pktin.type == SSH1_SMSG_FAILURE) {
fef97f43 1757 c_write("Server refused to allocate pty\r\n", 32);
1758 }
c5e9c988 1759 logevent("Allocated pty");
374330e2 1760 }
1761
4ba9b64b 1762 if (cfg.compression) {
1763 send_packet(SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END);
1764 do { crReturnV; } while (!ispkt);
1765 if (pktin.type != SSH1_SMSG_SUCCESS && pktin.type != SSH1_SMSG_FAILURE) {
1766 bombout(("Protocol confusion"));
1767 crReturnV;
1768 } else if (pktin.type == SSH1_SMSG_FAILURE) {
1769 c_write("Server refused to compress\r\n", 32);
1770 }
1771 logevent("Started compression");
1772 ssh1_compressing = TRUE;
1773 zlib_compress_init();
1774 zlib_decompress_init();
1775 }
1776
6abbf9e3 1777 if (*cfg.remote_cmd)
1778 send_packet(SSH1_CMSG_EXEC_CMD, PKT_STR, cfg.remote_cmd, PKT_END);
1779 else
1780 send_packet(SSH1_CMSG_EXEC_SHELL, PKT_END);
c5e9c988 1781 logevent("Started session");
374330e2 1782
1783 ssh_state = SSH_STATE_SESSION;
1784 if (size_needed)
1785 ssh_size();
1786
8ccc75b0 1787 ssh_send_ok = 1;
dacbd0e8 1788 ssh_channels = newtree234(ssh_channelcmp);
6f34e365 1789 begin_session();
374330e2 1790 while (1) {
1791 crReturnV;
1792 if (ispkt) {
e5574168 1793 if (pktin.type == SSH1_SMSG_STDOUT_DATA ||
1794 pktin.type == SSH1_SMSG_STDERR_DATA) {
fb09bf1c 1795 long len = GET_32BIT(pktin.body);
fe50e814 1796 from_backend(pktin.type == SSH1_SMSG_STDERR_DATA,
1797 pktin.body+4, len);
e5574168 1798 } else if (pktin.type == SSH1_MSG_DISCONNECT) {
21248260 1799 ssh_state = SSH_STATE_CLOSED;
c5e9c988 1800 logevent("Received disconnect request");
3257deae 1801 crReturnV;
dacbd0e8 1802 } else if (pktin.type == SSH1_SMSG_AGENT_OPEN) {
1803 /* Remote side is trying to open a channel to talk to our
1804 * agent. Give them back a local channel number. */
db7d555c 1805 unsigned i;
dacbd0e8 1806 struct ssh_channel *c;
1807 enum234 e;
db7d555c 1808
1809 /* Refuse if agent forwarding is disabled. */
1810 if (!ssh_agentfwd_enabled) {
1811 send_packet(SSH1_MSG_CHANNEL_OPEN_FAILURE,
1812 PKT_INT, GET_32BIT(pktin.body),
1813 PKT_END);
1814 } else {
1815 i = 1;
1816 for (c = first234(ssh_channels, &e); c; c = next234(&e)) {
1817 if (c->localid > i)
1818 break; /* found a free number */
1819 i = c->localid + 1;
1820 }
dcbde236 1821 c = smalloc(sizeof(struct ssh_channel));
db7d555c 1822 c->remoteid = GET_32BIT(pktin.body);
1823 c->localid = i;
1824 c->closes = 0;
1825 c->type = SSH1_SMSG_AGENT_OPEN;/* identify channel type */
1826 c->u.a.lensofar = 0;
1827 add234(ssh_channels, c);
1828 send_packet(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
1829 PKT_INT, c->remoteid, PKT_INT, c->localid,
1830 PKT_END);
1831 }
1832 } else if (pktin.type == SSH1_MSG_CHANNEL_CLOSE ||
1833 pktin.type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION) {
dacbd0e8 1834 /* Remote side closes a channel. */
d211621f 1835 unsigned i = GET_32BIT(pktin.body);
dacbd0e8 1836 struct ssh_channel *c;
1837 c = find234(ssh_channels, &i, ssh_channelfind);
1838 if (c) {
1839 int closetype;
1840 closetype = (pktin.type == SSH1_MSG_CHANNEL_CLOSE ? 1 : 2);
1841 send_packet(pktin.type, PKT_INT, c->remoteid, PKT_END);
1842 c->closes |= closetype;
1843 if (c->closes == 3) {
1844 del234(ssh_channels, c);
dcbde236 1845 sfree(c);
dacbd0e8 1846 }
1847 }
1848 } else if (pktin.type == SSH1_MSG_CHANNEL_DATA) {
1849 /* Data sent down one of our channels. */
1850 int i = GET_32BIT(pktin.body);
1851 int len = GET_32BIT(pktin.body+4);
1852 unsigned char *p = pktin.body+8;
1853 struct ssh_channel *c;
1854 c = find234(ssh_channels, &i, ssh_channelfind);
1855 if (c) {
1856 switch(c->type) {
1857 case SSH1_SMSG_AGENT_OPEN:
1858 /* Data for an agent message. Buffer it. */
1859 while (len > 0) {
1860 if (c->u.a.lensofar < 4) {
1861 int l = min(4 - c->u.a.lensofar, len);
1862 memcpy(c->u.a.msglen + c->u.a.lensofar, p, l);
1863 p += l; len -= l; c->u.a.lensofar += l;
1864 }
1865 if (c->u.a.lensofar == 4) {
1866 c->u.a.totallen = 4 + GET_32BIT(c->u.a.msglen);
dcbde236 1867 c->u.a.message = smalloc(c->u.a.totallen);
dacbd0e8 1868 memcpy(c->u.a.message, c->u.a.msglen, 4);
1869 }
1870 if (c->u.a.lensofar >= 4 && len > 0) {
1871 int l = min(c->u.a.totallen - c->u.a.lensofar, len);
1872 memcpy(c->u.a.message + c->u.a.lensofar, p, l);
1873 p += l; len -= l; c->u.a.lensofar += l;
1874 }
1875 if (c->u.a.lensofar == c->u.a.totallen) {
1876 void *reply, *sentreply;
1877 int replylen;
1878 agent_query(c->u.a.message, c->u.a.totallen,
1879 &reply, &replylen);
1880 if (reply)
1881 sentreply = reply;
1882 else {
1883 /* Fake SSH_AGENT_FAILURE. */
1884 sentreply = "\0\0\0\1\5";
1885 replylen = 5;
1886 }
1887 send_packet(SSH1_MSG_CHANNEL_DATA,
1888 PKT_INT, c->remoteid,
1889 PKT_INT, replylen,
1890 PKT_DATA, sentreply, replylen,
1891 PKT_END);
1892 if (reply)
dcbde236 1893 sfree(reply);
1894 sfree(c->u.a.message);
dacbd0e8 1895 c->u.a.lensofar = 0;
1896 }
1897 }
1898 break;
1899 }
1900 }
e5574168 1901 } else if (pktin.type == SSH1_SMSG_SUCCESS) {
972a41c8 1902 /* may be from EXEC_SHELL on some servers */
e5574168 1903 } else if (pktin.type == SSH1_SMSG_FAILURE) {
972a41c8 1904 /* may be from EXEC_SHELL on some servers
374330e2 1905 * if no pty is available or in other odd cases. Ignore */
e5574168 1906 } else if (pktin.type == SSH1_SMSG_EXIT_STATUS) {
1907 send_packet(SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
374330e2 1908 } else {
8d5de777 1909 bombout(("Strange packet received: type %d", pktin.type));
1910 crReturnV;
374330e2 1911 }
1912 } else {
8df7a775 1913 while (inlen > 0) {
1914 int len = min(inlen, 512);
1915 send_packet(SSH1_CMSG_STDIN_DATA,
1916 PKT_INT, len, PKT_DATA, in, len, PKT_END);
1917 in += len;
1918 inlen -= len;
1919 }
374330e2 1920 }
1921 }
1922
1923 crFinishV;
1924}
1925
1926/*
e5574168 1927 * Utility routine for decoding comma-separated strings in KEXINIT.
1928 */
75cab814 1929static int in_commasep_string(char *needle, char *haystack, int haylen) {
e5574168 1930 int needlen = strlen(needle);
1931 while (1) {
1932 /*
1933 * Is it at the start of the string?
1934 */
1935 if (haylen >= needlen && /* haystack is long enough */
1936 !memcmp(needle, haystack, needlen) && /* initial match */
1937 (haylen == needlen || haystack[needlen] == ',')
1938 /* either , or EOS follows */
1939 )
1940 return 1;
1941 /*
1942 * If not, search for the next comma and resume after that.
1943 * If no comma found, terminate.
1944 */
1945 while (haylen > 0 && *haystack != ',')
1946 haylen--, haystack++;
1947 if (haylen == 0)
1948 return 0;
1949 haylen--, haystack++; /* skip over comma itself */
1950 }
1951}
1952
1953/*
d39f364a 1954 * SSH2 key creation method.
1955 */
75cab814 1956static void ssh2_mkkey(Bignum K, char *H, char chr, char *keyspace) {
d39f364a 1957 SHA_State s;
1958 /* First 20 bytes. */
1959 SHA_Init(&s);
1960 sha_mpint(&s, K);
1961 SHA_Bytes(&s, H, 20);
1962 SHA_Bytes(&s, &chr, 1);
1963 SHA_Bytes(&s, H, 20);
1964 SHA_Final(&s, keyspace);
1965 /* Next 20 bytes. */
1966 SHA_Init(&s);
1967 sha_mpint(&s, K);
1968 SHA_Bytes(&s, H, 20);
1969 SHA_Bytes(&s, keyspace, 20);
1970 SHA_Final(&s, keyspace+20);
1971}
1972
1973/*
7cca0d81 1974 * Handle the SSH2 transport layer.
e5574168 1975 */
7cca0d81 1976static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt)
e5574168 1977{
1978 static int i, len;
1979 static char *str;
1980 static Bignum e, f, K;
7591b9ff 1981 static const struct ssh_mac **maclist;
8b2715b2 1982 static int nmacs;
57476f6b 1983 static const struct ssh_cipher *cscipher_tobe = NULL;
1984 static const struct ssh_cipher *sccipher_tobe = NULL;
1985 static const struct ssh_mac *csmac_tobe = NULL;
1986 static const struct ssh_mac *scmac_tobe = NULL;
1987 static const struct ssh_compress *cscomp_tobe = NULL;
1988 static const struct ssh_compress *sccomp_tobe = NULL;
d5859615 1989 static char *hostkeydata, *sigdata, *keystr, *fingerprint;
e5574168 1990 static int hostkeylen, siglen;
e055a386 1991 static void *hkey; /* actual host key */
e5574168 1992 static unsigned char exchange_hash[20];
d39f364a 1993 static unsigned char keyspace[40];
57476f6b 1994 static const struct ssh_cipher *preferred_cipher;
4ba9b64b 1995 static const struct ssh_compress *preferred_comp;
e5574168 1996
1997 crBegin;
7cca0d81 1998 random_init();
e5574168 1999
5e8358ad 2000 /*
4ba9b64b 2001 * Set up the preferred cipher and compression.
5e8358ad 2002 */
2003 if (cfg.cipher == CIPHER_BLOWFISH) {
57476f6b 2004 preferred_cipher = &ssh_blowfish_ssh2;
5e8358ad 2005 } else if (cfg.cipher == CIPHER_DES) {
2006 logevent("Single DES not supported in SSH2; using 3DES");
57476f6b 2007 preferred_cipher = &ssh_3des_ssh2;
5e8358ad 2008 } else if (cfg.cipher == CIPHER_3DES) {
57476f6b 2009 preferred_cipher = &ssh_3des_ssh2;
5e8358ad 2010 } else {
2011 /* Shouldn't happen, but we do want to initialise to _something_. */
57476f6b 2012 preferred_cipher = &ssh_3des_ssh2;
5e8358ad 2013 }
4ba9b64b 2014 if (cfg.compression)
2015 preferred_comp = &ssh_zlib;
2016 else
2017 preferred_comp = &ssh_comp_none;
5e8358ad 2018
7591b9ff 2019 /*
2020 * Be prepared to work around the buggy MAC problem.
2021 */
2022 if (cfg.buggymac)
8b2715b2 2023 maclist = buggymacs, nmacs = lenof(buggymacs);
7591b9ff 2024 else
8b2715b2 2025 maclist = macs, nmacs = lenof(macs);
7591b9ff 2026
7cca0d81 2027 begin_key_exchange:
e5574168 2028 /*
2029 * Construct and send our key exchange packet.
2030 */
2031 ssh2_pkt_init(SSH2_MSG_KEXINIT);
2032 for (i = 0; i < 16; i++)
2033 ssh2_pkt_addbyte((unsigned char)random_byte());
2034 /* List key exchange algorithms. */
2035 ssh2_pkt_addstring_start();
2036 for (i = 0; i < lenof(kex_algs); i++) {
2037 ssh2_pkt_addstring_str(kex_algs[i]->name);
2038 if (i < lenof(kex_algs)-1)
2039 ssh2_pkt_addstring_str(",");
2040 }
2041 /* List server host key algorithms. */
2042 ssh2_pkt_addstring_start();
2043 for (i = 0; i < lenof(hostkey_algs); i++) {
2044 ssh2_pkt_addstring_str(hostkey_algs[i]->name);
2045 if (i < lenof(hostkey_algs)-1)
2046 ssh2_pkt_addstring_str(",");
2047 }
2048 /* List client->server encryption algorithms. */
2049 ssh2_pkt_addstring_start();
729e54b4 2050 for (i = 0; i < lenof(ciphers)+1; i++) {
2051 const struct ssh_cipher *c = i==0 ? preferred_cipher : ciphers[i-1];
57476f6b 2052 ssh2_pkt_addstring_str(c->name);
729e54b4 2053 if (i < lenof(ciphers))
e5574168 2054 ssh2_pkt_addstring_str(",");
2055 }
2056 /* List server->client encryption algorithms. */
2057 ssh2_pkt_addstring_start();
729e54b4 2058 for (i = 0; i < lenof(ciphers)+1; i++) {
2059 const struct ssh_cipher *c = i==0 ? preferred_cipher : ciphers[i-1];
57476f6b 2060 ssh2_pkt_addstring_str(c->name);
729e54b4 2061 if (i < lenof(ciphers))
e5574168 2062 ssh2_pkt_addstring_str(",");
2063 }
2064 /* List client->server MAC algorithms. */
2065 ssh2_pkt_addstring_start();
8b2715b2 2066 for (i = 0; i < nmacs; i++) {
7591b9ff 2067 ssh2_pkt_addstring_str(maclist[i]->name);
8b2715b2 2068 if (i < nmacs-1)
e5574168 2069 ssh2_pkt_addstring_str(",");
2070 }
2071 /* List server->client MAC algorithms. */
2072 ssh2_pkt_addstring_start();
8b2715b2 2073 for (i = 0; i < nmacs; i++) {
7591b9ff 2074 ssh2_pkt_addstring_str(maclist[i]->name);
8b2715b2 2075 if (i < nmacs-1)
e5574168 2076 ssh2_pkt_addstring_str(",");
2077 }
2078 /* List client->server compression algorithms. */
2079 ssh2_pkt_addstring_start();
4ba9b64b 2080 for (i = 0; i < lenof(compressions)+1; i++) {
2081 const struct ssh_compress *c = i==0 ? preferred_comp : compressions[i-1];
2082 ssh2_pkt_addstring_str(c->name);
2083 if (i < lenof(compressions))
e5574168 2084 ssh2_pkt_addstring_str(",");
2085 }
2086 /* List server->client compression algorithms. */
2087 ssh2_pkt_addstring_start();
4ba9b64b 2088 for (i = 0; i < lenof(compressions)+1; i++) {
2089 const struct ssh_compress *c = i==0 ? preferred_comp : compressions[i-1];
2090 ssh2_pkt_addstring_str(c->name);
2091 if (i < lenof(compressions))
e5574168 2092 ssh2_pkt_addstring_str(",");
2093 }
2094 /* List client->server languages. Empty list. */
2095 ssh2_pkt_addstring_start();
2096 /* List server->client languages. Empty list. */
2097 ssh2_pkt_addstring_start();
2098 /* First KEX packet does _not_ follow, because we're not that brave. */
2099 ssh2_pkt_addbool(FALSE);
2100 /* Reserved. */
2101 ssh2_pkt_adduint32(0);
2102 sha_string(&exhash, pktout.data+5, pktout.length-5);
2103 ssh2_pkt_send();
2104
2105 if (!ispkt) crWaitUntil(ispkt);
2106 sha_string(&exhash, pktin.data+5, pktin.length-5);
2107
2108 /*
2109 * Now examine the other side's KEXINIT to see what we're up
2110 * to.
2111 */
7cca0d81 2112 if (pktin.type != SSH2_MSG_KEXINIT) {
8d5de777 2113 bombout(("expected key exchange packet from server"));
2114 crReturn(0);
7cca0d81 2115 }
e5574168 2116 kex = NULL; hostkey = NULL; cscipher_tobe = NULL; sccipher_tobe = NULL;
2117 csmac_tobe = NULL; scmac_tobe = NULL; cscomp_tobe = NULL; sccomp_tobe = NULL;
2118 pktin.savedpos += 16; /* skip garbage cookie */
2119 ssh2_pkt_getstring(&str, &len); /* key exchange algorithms */
2120 for (i = 0; i < lenof(kex_algs); i++) {
2121 if (in_commasep_string(kex_algs[i]->name, str, len)) {
2122 kex = kex_algs[i];
2123 break;
2124 }
2125 }
2126 ssh2_pkt_getstring(&str, &len); /* host key algorithms */
2127 for (i = 0; i < lenof(hostkey_algs); i++) {
2128 if (in_commasep_string(hostkey_algs[i]->name, str, len)) {
2129 hostkey = hostkey_algs[i];
2130 break;
2131 }
2132 }
2133 ssh2_pkt_getstring(&str, &len); /* client->server cipher */
729e54b4 2134 for (i = 0; i < lenof(ciphers)+1; i++) {
2135 const struct ssh_cipher *c = i==0 ? preferred_cipher : ciphers[i-1];
57476f6b 2136 if (in_commasep_string(c->name, str, len)) {
729e54b4 2137 cscipher_tobe = c;
e5574168 2138 break;
2139 }
2140 }
2141 ssh2_pkt_getstring(&str, &len); /* server->client cipher */
729e54b4 2142 for (i = 0; i < lenof(ciphers)+1; i++) {
2143 const struct ssh_cipher *c = i==0 ? preferred_cipher : ciphers[i-1];
57476f6b 2144 if (in_commasep_string(c->name, str, len)) {
729e54b4 2145 sccipher_tobe = c;
e5574168 2146 break;
2147 }
2148 }
2149 ssh2_pkt_getstring(&str, &len); /* client->server mac */
8b2715b2 2150 for (i = 0; i < nmacs; i++) {
7591b9ff 2151 if (in_commasep_string(maclist[i]->name, str, len)) {
2152 csmac_tobe = maclist[i];
e5574168 2153 break;
2154 }
2155 }
2156 ssh2_pkt_getstring(&str, &len); /* server->client mac */
8b2715b2 2157 for (i = 0; i < nmacs; i++) {
7591b9ff 2158 if (in_commasep_string(maclist[i]->name, str, len)) {
2159 scmac_tobe = maclist[i];
e5574168 2160 break;
2161 }
2162 }
2163 ssh2_pkt_getstring(&str, &len); /* client->server compression */
4ba9b64b 2164 for (i = 0; i < lenof(compressions)+1; i++) {
2165 const struct ssh_compress *c = i==0 ? preferred_comp : compressions[i-1];
2166 if (in_commasep_string(c->name, str, len)) {
2167 cscomp_tobe = c;
e5574168 2168 break;
2169 }
2170 }
2171 ssh2_pkt_getstring(&str, &len); /* server->client compression */
4ba9b64b 2172 for (i = 0; i < lenof(compressions)+1; i++) {
2173 const struct ssh_compress *c = i==0 ? preferred_comp : compressions[i-1];
2174 if (in_commasep_string(c->name, str, len)) {
2175 sccomp_tobe = c;
e5574168 2176 break;
2177 }
2178 }
e5574168 2179
2180 /*
2181 * Currently we only support Diffie-Hellman and DSS, so let's
2182 * bomb out if those aren't selected.
2183 */
8d5de777 2184 if (kex != &ssh_diffiehellman || hostkey != &ssh_dss) {
2185 bombout(("internal fault: chaos in SSH 2 transport layer"));
2186 crReturn(0);
2187 }
e5574168 2188
2189 /*
2190 * Now we begin the fun. Generate and send e for Diffie-Hellman.
2191 */
2192 e = dh_create_e();
e5574168 2193 ssh2_pkt_init(SSH2_MSG_KEXDH_INIT);
2194 ssh2_pkt_addmp(e);
2195 ssh2_pkt_send();
2196
2197 crWaitUntil(ispkt);
7cca0d81 2198 if (pktin.type != SSH2_MSG_KEXDH_REPLY) {
8d5de777 2199 bombout(("expected key exchange packet from server"));
2200 crReturn(0);
7cca0d81 2201 }
e5574168 2202 ssh2_pkt_getstring(&hostkeydata, &hostkeylen);
2203 f = ssh2_pkt_getmp();
e5574168 2204 ssh2_pkt_getstring(&sigdata, &siglen);
2205
2206 K = dh_find_K(f);
e5574168 2207
2208 sha_string(&exhash, hostkeydata, hostkeylen);
2209 sha_mpint(&exhash, e);
2210 sha_mpint(&exhash, f);
2211 sha_mpint(&exhash, K);
2212 SHA_Final(&exhash, exchange_hash);
2213
7cca0d81 2214#if 0
e5574168 2215 debug(("Exchange hash is:\r\n"));
2216 for (i = 0; i < 20; i++)
2217 debug((" %02x", exchange_hash[i]));
2218 debug(("\r\n"));
7cca0d81 2219#endif
2220
e055a386 2221 hkey = hostkey->newkey(hostkeydata, hostkeylen);
2222 if (!hostkey->verifysig(hkey, sigdata, siglen, exchange_hash, 20)) {
8d5de777 2223 bombout(("Server failed host key check"));
2224 crReturn(0);
2225 }
e5574168 2226
2227 /*
7cca0d81 2228 * Expect SSH2_MSG_NEWKEYS from server.
d39f364a 2229 */
7cca0d81 2230 crWaitUntil(ispkt);
8d5de777 2231 if (pktin.type != SSH2_MSG_NEWKEYS) {
2232 bombout(("expected new-keys packet from server"));
2233 crReturn(0);
2234 }
d39f364a 2235
2236 /*
7cca0d81 2237 * Authenticate remote host: verify host key. (We've already
2238 * checked the signature of the exchange hash.)
e5574168 2239 */
e055a386 2240 keystr = hostkey->fmtkey(hkey);
2241 fingerprint = hostkey->fingerprint(hkey);
d4857987 2242 verify_ssh_host_key(savedhost, savedport, hostkey->keytype,
2243 keystr, fingerprint);
d5859615 2244 logevent("Host key fingerprint is:");
2245 logevent(fingerprint);
dcbde236 2246 sfree(fingerprint);
2247 sfree(keystr);
e055a386 2248 hostkey->freekey(hkey);
d39f364a 2249
2250 /*
7cca0d81 2251 * Send SSH2_MSG_NEWKEYS.
d39f364a 2252 */
2253 ssh2_pkt_init(SSH2_MSG_NEWKEYS);
2254 ssh2_pkt_send();
d39f364a 2255
2256 /*
2257 * Create and initialise session keys.
2258 */
2259 cscipher = cscipher_tobe;
2260 sccipher = sccipher_tobe;
2261 csmac = csmac_tobe;
2262 scmac = scmac_tobe;
2263 cscomp = cscomp_tobe;
2264 sccomp = sccomp_tobe;
4ba9b64b 2265 cscomp->compress_init();
2266 sccomp->decompress_init();
d39f364a 2267 /*
2268 * Set IVs after keys.
2269 */
2270 ssh2_mkkey(K, exchange_hash, 'C', keyspace); cscipher->setcskey(keyspace);
2271 ssh2_mkkey(K, exchange_hash, 'D', keyspace); cscipher->setsckey(keyspace);
2272 ssh2_mkkey(K, exchange_hash, 'A', keyspace); cscipher->setcsiv(keyspace);
2273 ssh2_mkkey(K, exchange_hash, 'B', keyspace); sccipher->setsciv(keyspace);
2274 ssh2_mkkey(K, exchange_hash, 'E', keyspace); csmac->setcskey(keyspace);
2275 ssh2_mkkey(K, exchange_hash, 'F', keyspace); scmac->setsckey(keyspace);
2276
033b4cef 2277 /*
7cca0d81 2278 * Now we're encrypting. Begin returning 1 to the protocol main
2279 * function so that other things can run on top of the
2280 * transport. If we ever see a KEXINIT, we must go back to the
2281 * start.
033b4cef 2282 */
7cca0d81 2283 do {
2284 crReturn(1);
2285 } while (!(ispkt && pktin.type == SSH2_MSG_KEXINIT));
2286 goto begin_key_exchange;
e5574168 2287
2288 crFinish(1);
2289}
2290
7cca0d81 2291/*
2292 * Handle the SSH2 userauth and connection layers.
2293 */
2294static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt)
2295{
7cca0d81 2296 static unsigned long remote_winsize;
2297 static unsigned long remote_maxpkt;
2298
e5574168 2299 crBegin;
2300
7cca0d81 2301 /*
2302 * Request userauth protocol, and await a response to it.
2303 */
2304 ssh2_pkt_init(SSH2_MSG_SERVICE_REQUEST);
2305 ssh2_pkt_addstring("ssh-userauth");
2306 ssh2_pkt_send();
2307 crWaitUntilV(ispkt);
8d5de777 2308 if (pktin.type != SSH2_MSG_SERVICE_ACCEPT) {
2309 bombout(("Server refused user authentication protocol"));
2310 crReturnV;
2311 }
7cca0d81 2312
2313 /*
2314 * FIXME: currently we support only password authentication.
2315 * (This places us technically in violation of the SSH2 spec.
2316 * We must fix this.)
2317 */
2318 while (1) {
2319 /*
2320 * Get a username and a password.
2321 */
2322 static char username[100];
2323 static char password[100];
2324 static int pos = 0;
2325 static char c;
e5574168 2326
67779be7 2327 if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
7cca0d81 2328 c_write("login as: ", 10);
67779be7 2329 ssh_send_ok = 1;
7cca0d81 2330 while (pos >= 0) {
2331 crWaitUntilV(!ispkt);
2332 while (inlen--) switch (c = *in++) {
2333 case 10: case 13:
2334 username[pos] = 0;
2335 pos = -1;
2336 break;
2337 case 8: case 127:
2338 if (pos > 0) {
2339 c_write("\b \b", 3);
2340 pos--;
2341 }
2342 break;
2343 case 21: case 27:
2344 while (pos > 0) {
2345 c_write("\b \b", 3);
2346 pos--;
2347 }
2348 break;
2349 case 3: case 4:
2350 random_save_seed();
2351 exit(0);
2352 break;
2353 default:
2354 if (((c >= ' ' && c <= '~') ||
2355 ((unsigned char)c >= 160)) && pos < 40) {
2356 username[pos++] = c;
2357 c_write(&c, 1);
2358 }
2359 break;
2360 }
2361 }
2362 c_write("\r\n", 2);
2363 username[strcspn(username, "\n\r")] = '\0';
2364 } else {
2365 char stuff[200];
2366 strncpy(username, cfg.username, 99);
2367 username[99] = '\0';
67779be7 2368 if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
7cca0d81 2369 sprintf(stuff, "Using username \"%s\".\r\n", username);
2370 c_write(stuff, strlen(stuff));
2371 }
2372 }
2373
d8426c54 2374 if (ssh_get_password) {
7cca0d81 2375 char prompt[200];
b585ec46 2376 sprintf(prompt, "%.90s@%.90s's password: ", username, savedhost);
7cca0d81 2377 if (!ssh_get_password(prompt, password, sizeof(password))) {
2378 /*
2379 * get_password failed to get a password (for
2380 * example because one was supplied on the command
2381 * line which has already failed to work).
2382 * Terminate.
2383 */
2384 logevent("No more passwords to try");
2385 ssh_state = SSH_STATE_CLOSED;
2386 crReturnV;
2387 }
2388 } else {
2389 c_write("password: ", 10);
67779be7 2390 ssh_send_ok = 1;
7cca0d81 2391
2392 pos = 0;
2393 while (pos >= 0) {
2394 crWaitUntilV(!ispkt);
2395 while (inlen--) switch (c = *in++) {
2396 case 10: case 13:
2397 password[pos] = 0;
2398 pos = -1;
2399 break;
2400 case 8: case 127:
2401 if (pos > 0)
2402 pos--;
2403 break;
2404 case 21: case 27:
2405 pos = 0;
2406 break;
2407 case 3: case 4:
2408 random_save_seed();
2409 exit(0);
2410 break;
2411 default:
2412 if (((c >= ' ' && c <= '~') ||
2413 ((unsigned char)c >= 160)) && pos < 40)
2414 password[pos++] = c;
2415 break;
2416 }
2417 }
2418 c_write("\r\n", 2);
2419 }
2420
2421 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
2422 ssh2_pkt_addstring(username);
2423 ssh2_pkt_addstring("ssh-connection"); /* service requested */
2424 ssh2_pkt_addstring("password");
2425 ssh2_pkt_addbool(FALSE);
2426 ssh2_pkt_addstring(password);
2427 ssh2_pkt_send();
2428
2429 crWaitUntilV(ispkt);
2430 if (pktin.type != SSH2_MSG_USERAUTH_SUCCESS) {
2431 c_write("Access denied\r\n", 15);
2432 logevent("Authentication refused");
2433 } else
2434 break;
2435 }
2436
2437 /*
2438 * Now we're authenticated for the connection protocol. The
2439 * connection protocol will automatically have started at this
2440 * point; there's no need to send SERVICE_REQUEST.
2441 */
2442
2443 /*
2444 * So now create a channel with a session in it.
2445 */
dcbde236 2446 mainchan = smalloc(sizeof(struct ssh_channel));
d211621f 2447 mainchan->localid = 100; /* as good as any */
7cca0d81 2448 ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN);
2449 ssh2_pkt_addstring("session");
d211621f 2450 ssh2_pkt_adduint32(mainchan->localid);
cf6e59d6 2451 ssh2_pkt_adduint32(0x8000UL); /* our window size */
d211621f 2452 ssh2_pkt_adduint32(0x4000UL); /* our max pkt size */
7cca0d81 2453 ssh2_pkt_send();
2454 crWaitUntilV(ispkt);
2455 if (pktin.type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
8d5de777 2456 bombout(("Server refused to open a session"));
2457 crReturnV;
7cca0d81 2458 /* FIXME: error data comes back in FAILURE packet */
2459 }
d211621f 2460 if (ssh2_pkt_getuint32() != mainchan->localid) {
8d5de777 2461 bombout(("Server's channel confirmation cited wrong channel"));
2462 crReturnV;
7cca0d81 2463 }
d211621f 2464 mainchan->remoteid = ssh2_pkt_getuint32();
2465 mainchan->u.v2.remwindow = ssh2_pkt_getuint32();
2466 mainchan->u.v2.remmaxpkt = ssh2_pkt_getuint32();
2467 mainchan->u.v2.outbuffer = NULL;
2468 mainchan->u.v2.outbuflen = mainchan->u.v2.outbufsize = 0;
7cca0d81 2469 logevent("Opened channel for session");
2470
2471 /*
2472 * Now allocate a pty for the session.
2473 */
67779be7 2474 if (!cfg.nopty) {
2475 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
2476 ssh2_pkt_adduint32(mainchan->remoteid); /* recipient channel */
2477 ssh2_pkt_addstring("pty-req");
2478 ssh2_pkt_addbool(1); /* want reply */
2479 ssh2_pkt_addstring(cfg.termtype);
2480 ssh2_pkt_adduint32(cols);
2481 ssh2_pkt_adduint32(rows);
2482 ssh2_pkt_adduint32(0); /* pixel width */
2483 ssh2_pkt_adduint32(0); /* pixel height */
2484 ssh2_pkt_addstring_start();
2485 ssh2_pkt_addstring_data("\0", 1);/* TTY_OP_END, no special options */
2486 ssh2_pkt_send();
6e48c3fe 2487 ssh_state = SSH_STATE_INTERMED;
7cca0d81 2488
67779be7 2489 do {
2490 crWaitUntilV(ispkt);
2491 if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
2492 /* FIXME: be able to handle other channels here */
2493 if (ssh2_pkt_getuint32() != mainchan->localid)
2494 continue; /* wrong channel */
2495 mainchan->u.v2.remwindow += ssh2_pkt_getuint32();
2496 }
2497 } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
7cca0d81 2498
67779be7 2499 if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
2500 if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
8d5de777 2501 bombout(("Server got confused by pty request"));
2502 crReturnV;
67779be7 2503 }
2504 c_write("Server refused to allocate pty\r\n", 32);
2505 } else {
2506 logevent("Allocated pty");
7cca0d81 2507 }
7cca0d81 2508 }
2509
2510 /*
67779be7 2511 * Start a shell or a remote command.
7cca0d81 2512 */
2513 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
d211621f 2514 ssh2_pkt_adduint32(mainchan->remoteid); /* recipient channel */
67779be7 2515 if (*cfg.remote_cmd) {
2516 ssh2_pkt_addstring("exec");
2517 ssh2_pkt_addbool(1); /* want reply */
2518 ssh2_pkt_addstring(cfg.remote_cmd);
2519 } else {
2520 ssh2_pkt_addstring("shell");
2521 ssh2_pkt_addbool(1); /* want reply */
2522 }
7cca0d81 2523 ssh2_pkt_send();
d211621f 2524 do {
7cca0d81 2525 crWaitUntilV(ispkt);
d211621f 2526 if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
2527 /* FIXME: be able to handle other channels here */
2528 if (ssh2_pkt_getuint32() != mainchan->localid)
2529 continue; /* wrong channel */
2530 mainchan->u.v2.remwindow += ssh2_pkt_getuint32();
2531 }
7cca0d81 2532 } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
2533 if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
2534 if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
8d5de777 2535 bombout(("Server got confused by shell/command request"));
2536 crReturnV;
7cca0d81 2537 }
8d5de777 2538 bombout(("Server refused to start a shell/command"));
2539 crReturnV;
7cca0d81 2540 } else {
8d5de777 2541 logevent("Started a shell/command");
7cca0d81 2542 }
2543
6e48c3fe 2544 ssh_state = SSH_STATE_SESSION;
2545 if (size_needed)
2546 ssh_size();
2547
7cca0d81 2548 /*
2549 * Transfer data!
2550 */
8ccc75b0 2551 ssh_send_ok = 1;
6f34e365 2552 begin_session();
7cca0d81 2553 while (1) {
d211621f 2554 static int try_send;
e5574168 2555 crReturnV;
d211621f 2556 try_send = FALSE;
7cca0d81 2557 if (ispkt) {
2558 if (pktin.type == SSH2_MSG_CHANNEL_DATA ||
2559 pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA) {
2560 char *data;
2561 int length;
d211621f 2562 /* FIXME: be able to handle other channels here */
2563 if (ssh2_pkt_getuint32() != mainchan->localid)
7cca0d81 2564 continue; /* wrong channel */
2565 if (pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
2566 ssh2_pkt_getuint32() != SSH2_EXTENDED_DATA_STDERR)
2567 continue; /* extended but not stderr */
2568 ssh2_pkt_getstring(&data, &length);
d211621f 2569 if (data) {
fe50e814 2570 from_backend(pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA,
2571 data, length);
d211621f 2572 /*
2573 * Enlarge the window again at the remote side,
2574 * just in case it ever runs down and they fail
2575 * to send us any more data.
2576 */
2577 ssh2_pkt_init(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
2578 ssh2_pkt_adduint32(mainchan->remoteid);
2579 ssh2_pkt_adduint32(length);
2580 ssh2_pkt_send();
2581 }
7cca0d81 2582 } else if (pktin.type == SSH2_MSG_DISCONNECT) {
2583 ssh_state = SSH_STATE_CLOSED;
d211621f 2584 logevent("Received disconnect message");
3257deae 2585 crReturnV;
7cca0d81 2586 } else if (pktin.type == SSH2_MSG_CHANNEL_REQUEST) {
2587 continue; /* exit status et al; ignore (FIXME?) */
d211621f 2588 } else if (pktin.type == SSH2_MSG_CHANNEL_EOF) {
2589 continue; /* remote sends EOF; ignore */
2590 } else if (pktin.type == SSH2_MSG_CHANNEL_CLOSE) {
2591 /* FIXME: be able to handle other channels here */
2592 if (ssh2_pkt_getuint32() != mainchan->localid)
2593 continue; /* wrong channel */
2594 ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE);
2595 ssh2_pkt_adduint32(mainchan->remoteid);
2596 ssh2_pkt_send();
2597 /* FIXME: mark the channel as closed */
2598 if (1 /* FIXME: "all channels are closed" */) {
2599 logevent("All channels closed. Disconnecting");
2600 ssh2_pkt_init(SSH2_MSG_DISCONNECT);
9005f3ba 2601 ssh2_pkt_adduint32(SSH2_DISCONNECT_BY_APPLICATION);
2602 ssh2_pkt_addstring("All open channels closed");
2603 ssh2_pkt_addstring("en"); /* language tag */
d211621f 2604 ssh2_pkt_send();
cf6e59d6 2605 ssh_state = SSH_STATE_CLOSED;
3257deae 2606 crReturnV;
d211621f 2607 }
2608 continue; /* remote sends close; ignore (FIXME) */
7cca0d81 2609 } else if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
d211621f 2610 /* FIXME: be able to handle other channels here */
2611 if (ssh2_pkt_getuint32() != mainchan->localid)
2612 continue; /* wrong channel */
2613 mainchan->u.v2.remwindow += ssh2_pkt_getuint32();
2614 try_send = TRUE;
7cca0d81 2615 } else {
8d5de777 2616 bombout(("Strange packet received: type %d", pktin.type));
2617 crReturnV;
7cca0d81 2618 }
2619 } else {
d211621f 2620 /*
2621 * We have spare data. Add it to the channel buffer.
2622 */
2623 if (mainchan->u.v2.outbufsize <
2624 mainchan->u.v2.outbuflen + inlen) {
2625 mainchan->u.v2.outbufsize =
2626 mainchan->u.v2.outbuflen + inlen + 1024;
2627 mainchan->u.v2.outbuffer = srealloc(mainchan->u.v2.outbuffer,
2628 mainchan->u.v2.outbufsize);
2629 }
2630 memcpy(mainchan->u.v2.outbuffer + mainchan->u.v2.outbuflen,
2631 in, inlen);
2632 mainchan->u.v2.outbuflen += inlen;
2633 try_send = TRUE;
7cca0d81 2634 }
d211621f 2635 if (try_send) {
2636 /*
2637 * Try to send data on the channel if we can. (FIXME:
2638 * on _all_ channels.)
2639 */
2640 while (mainchan->u.v2.remwindow > 0 &&
2641 mainchan->u.v2.outbuflen > 0) {
2642 unsigned len = mainchan->u.v2.remwindow;
2643 if (len > mainchan->u.v2.outbuflen)
2644 len = mainchan->u.v2.outbuflen;
2645 if (len > mainchan->u.v2.remmaxpkt)
2646 len = mainchan->u.v2.remmaxpkt;
2647 ssh2_pkt_init(SSH2_MSG_CHANNEL_DATA);
2648 ssh2_pkt_adduint32(mainchan->remoteid);
2649 ssh2_pkt_addstring_start();
2650 ssh2_pkt_addstring_data(mainchan->u.v2.outbuffer, len);
2651 ssh2_pkt_send();
2652 mainchan->u.v2.outbuflen -= len;
2653 memmove(mainchan->u.v2.outbuffer, mainchan->u.v2.outbuffer+len,
2654 mainchan->u.v2.outbuflen);
2655 mainchan->u.v2.remwindow -= len;
2656 }
2657 }
e5574168 2658 }
2659
2660 crFinishV;
2661}
2662
2663/*
7cca0d81 2664 * Handle the top-level SSH2 protocol.
2665 */
2666static void ssh2_protocol(unsigned char *in, int inlen, int ispkt)
2667{
2668 if (do_ssh2_transport(in, inlen, ispkt) == 0)
2669 return;
2670 do_ssh2_authconn(in, inlen, ispkt);
2671}
2672
2673/*
8df7a775 2674 * Called to set up the connection.
374330e2 2675 *
2676 * Returns an error message, or NULL on success.
374330e2 2677 */
8df7a775 2678static char *ssh_init (char *host, int port, char **realhost) {
fb09bf1c 2679 char *p;
8f203108 2680
2681#ifdef MSCRYPTOAPI
2682 if(crypto_startup() == 0)
2683 return "Microsoft high encryption pack not installed!";
2684#endif
374330e2 2685
8df7a775 2686 ssh_send_ok = 0;
2687
fb09bf1c 2688 p = connect_to_host(host, port, realhost);
2689 if (p != NULL)
2690 return p;
374330e2 2691
374330e2 2692 return NULL;
2693}
2694
2695/*
374330e2 2696 * Called to send data down the Telnet connection.
2697 */
2698static void ssh_send (char *buf, int len) {
f78051a1 2699 if (s == NULL || ssh_protocol == NULL)
374330e2 2700 return;
2701
2702 ssh_protocol(buf, len, 0);
2703}
2704
2705/*
6e48c3fe 2706 * Called to set the size of the window from SSH's POV.
374330e2 2707 */
2708static void ssh_size(void) {
2709 switch (ssh_state) {
2710 case SSH_STATE_BEFORE_SIZE:
21248260 2711 case SSH_STATE_CLOSED:
374330e2 2712 break; /* do nothing */
2713 case SSH_STATE_INTERMED:
2714 size_needed = TRUE; /* buffer for later */
2715 break;
2716 case SSH_STATE_SESSION:
fef97f43 2717 if (!cfg.nopty) {
6e48c3fe 2718 if (ssh_version == 1) {
2719 send_packet(SSH1_CMSG_WINDOW_SIZE,
2720 PKT_INT, rows, PKT_INT, cols,
2721 PKT_INT, 0, PKT_INT, 0, PKT_END);
2722 } else {
2723 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
2724 ssh2_pkt_adduint32(mainchan->remoteid);
2725 ssh2_pkt_addstring("window-change");
2726 ssh2_pkt_addbool(0);
2727 ssh2_pkt_adduint32(cols);
2728 ssh2_pkt_adduint32(rows);
2729 ssh2_pkt_adduint32(0);
2730 ssh2_pkt_adduint32(0);
2731 ssh2_pkt_send();
2732 }
fef97f43 2733 }
374330e2 2734 }
2735}
2736
2737/*
6abbf9e3 2738 * Send Telnet special codes. TS_EOF is useful for `plink', so you
2739 * can send an EOF and collect resulting output (e.g. `plink
2740 * hostname sort').
374330e2 2741 */
2742static void ssh_special (Telnet_Special code) {
6abbf9e3 2743 if (code == TS_EOF) {
67779be7 2744 if (ssh_version == 1) {
6abbf9e3 2745 send_packet(SSH1_CMSG_EOF, PKT_END);
2746 } else {
2747 ssh2_pkt_init(SSH2_MSG_CHANNEL_EOF);
d211621f 2748 ssh2_pkt_adduint32(mainchan->remoteid);
6abbf9e3 2749 ssh2_pkt_send();
2750 }
67779be7 2751 logevent("Sent EOF message");
ec55b220 2752 } else if (code == TS_PING) {
2753 if (ssh_version == 1) {
2754 send_packet(SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
2755 } else {
2756 ssh2_pkt_init(SSH2_MSG_IGNORE);
2757 ssh2_pkt_addstring_start();
2758 ssh2_pkt_send();
2759 }
6abbf9e3 2760 } else {
2761 /* do nothing */
2762 }
374330e2 2763}
2764
8df7a775 2765static Socket ssh_socket(void) { return s; }
8ccc75b0 2766
2767static int ssh_sendok(void) { return ssh_send_ok; }
fb09bf1c 2768
374330e2 2769Backend ssh_backend = {
2770 ssh_init,
374330e2 2771 ssh_send,
2772 ssh_size,
4017be6d 2773 ssh_special,
8ccc75b0 2774 ssh_socket,
97db3be4 2775 ssh_sendok,
2776 22
374330e2 2777};
Local modifications for Simon Tatham's `PuTTY' SSH client and terminal emulator