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Ensure ssh specials (EOF and PING) don't occur except in connection
[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
0db56f73 234static SHA_State exhash, exhashbase;
57476f6b 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 {
3687d221 260 SSH_STATE_PREPACKET,
57476f6b 261 SSH_STATE_BEFORE_SIZE,
262 SSH_STATE_INTERMED,
263 SSH_STATE_SESSION,
264 SSH_STATE_CLOSED
3687d221 265} ssh_state = SSH_STATE_PREPACKET;
57476f6b 266
3687d221 267static int size_needed = FALSE, eof_needed = FALSE;
57476f6b 268
269static struct Packet pktin = { 0, 0, NULL, NULL, 0 };
270static struct Packet pktout = { 0, 0, NULL, NULL, 0 };
271
272static int ssh_version;
273static void (*ssh_protocol)(unsigned char *in, int inlen, int ispkt);
274static void ssh1_protocol(unsigned char *in, int inlen, int ispkt);
275static void ssh2_protocol(unsigned char *in, int inlen, int ispkt);
276static void ssh_size(void);
3687d221 277static void ssh_special (Telnet_Special);
57476f6b 278
279static int (*s_rdpkt)(unsigned char **data, int *datalen);
280
281static struct rdpkt1_state_tag {
282 long len, pad, biglen, to_read;
283 unsigned long realcrc, gotcrc;
284 unsigned char *p;
285 int i;
286 int chunk;
287} rdpkt1_state;
288
960e736a 289static struct rdpkt2_state_tag {
290 long len, pad, payload, packetlen, maclen;
291 int i;
292 int cipherblk;
293 unsigned long incoming_sequence;
294} rdpkt2_state;
295
dacbd0e8 296static int ssh_channelcmp(void *av, void *bv) {
297 struct ssh_channel *a = (struct ssh_channel *)av;
298 struct ssh_channel *b = (struct ssh_channel *)bv;
299 if (a->localid < b->localid) return -1;
300 if (a->localid > b->localid) return +1;
301 return 0;
302}
303static int ssh_channelfind(void *av, void *bv) {
d211621f 304 unsigned *a = (unsigned *)av;
dacbd0e8 305 struct ssh_channel *b = (struct ssh_channel *)bv;
306 if (*a < b->localid) return -1;
307 if (*a > b->localid) return +1;
308 return 0;
309}
310
374330e2 311static void c_write (char *buf, int len) {
67779be7 312 if ((flags & FLAG_STDERR)) {
4017be6d 313 int i;
314 for (i = 0; i < len; i++)
315 if (buf[i] != '\r')
316 fputc(buf[i], stderr);
fb09bf1c 317 return;
318 }
fe50e814 319 from_backend(1, buf, len);
3bdaf79d 320}
321
fb09bf1c 322/*
323 * Collect incoming data in the incoming packet buffer.
e5574168 324 * Decipher and verify the packet when it is completely read.
325 * Drop SSH1_MSG_DEBUG and SSH1_MSG_IGNORE packets.
fb09bf1c 326 * Update the *data and *datalen variables.
327 * Return the additional nr of bytes needed, or 0 when
328 * a complete packet is available.
329 */
e5574168 330static int ssh1_rdpkt(unsigned char **data, int *datalen)
fb09bf1c 331{
57476f6b 332 struct rdpkt1_state_tag *st = &rdpkt1_state;
374330e2 333
334 crBegin;
374330e2 335
fb09bf1c 336next_packet:
37508af4 337
fb09bf1c 338 pktin.type = 0;
339 pktin.length = 0;
374330e2 340
57476f6b 341 for (st->i = st->len = 0; st->i < 4; st->i++) {
fb09bf1c 342 while ((*datalen) == 0)
57476f6b 343 crReturn(4-st->i);
344 st->len = (st->len << 8) + **data;
fb09bf1c 345 (*data)++, (*datalen)--;
346 }
374330e2 347
fb09bf1c 348#ifdef FWHACK
57476f6b 349 if (st->len == 0x52656d6f) { /* "Remo"te server has closed ... */
350 st->len = 0x300; /* big enough to carry to end */
fb09bf1c 351 }
352#endif
374330e2 353
57476f6b 354 st->pad = 8 - (st->len % 8);
355 st->biglen = st->len + st->pad;
356 pktin.length = st->len - 5;
fb09bf1c 357
57476f6b 358 if (pktin.maxlen < st->biglen) {
359 pktin.maxlen = st->biglen;
dcbde236 360 pktin.data = (pktin.data == NULL ? smalloc(st->biglen+APIEXTRA) :
361 srealloc(pktin.data, st->biglen+APIEXTRA));
fb09bf1c 362 if (!pktin.data)
363 fatalbox("Out of memory");
364 }
374330e2 365
57476f6b 366 st->to_read = st->biglen;
367 st->p = pktin.data;
368 while (st->to_read > 0) {
369 st->chunk = st->to_read;
fb09bf1c 370 while ((*datalen) == 0)
57476f6b 371 crReturn(st->to_read);
372 if (st->chunk > (*datalen))
373 st->chunk = (*datalen);
374 memcpy(st->p, *data, st->chunk);
375 *data += st->chunk;
376 *datalen -= st->chunk;
377 st->p += st->chunk;
378 st->to_read -= st->chunk;
fb09bf1c 379 }
374330e2 380
fb09bf1c 381 if (cipher)
57476f6b 382 cipher->decrypt(pktin.data, st->biglen);
698a5108 383#if 0
384 debug(("Got packet len=%d pad=%d\r\n", st->len, st->pad));
385 for (st->i = 0; st->i < st->biglen; st->i++)
386 debug((" %02x", (unsigned char)pktin.data[st->i]));
387 debug(("\r\n"));
388#endif
374330e2 389
57476f6b 390 st->realcrc = crc32(pktin.data, st->biglen-4);
391 st->gotcrc = GET_32BIT(pktin.data+st->biglen-4);
392 if (st->gotcrc != st->realcrc) {
8d5de777 393 bombout(("Incorrect CRC received on packet"));
394 crReturn(0);
fb09bf1c 395 }
572f871e 396
4ba9b64b 397 pktin.body = pktin.data + st->pad + 1;
398
399 if (ssh1_compressing) {
400 unsigned char *decompblk;
401 int decomplen;
402#if 0
403 int i;
404 debug(("Packet payload pre-decompression:\n"));
405 for (i = -1; i < pktin.length; i++)
406 debug((" %02x", (unsigned char)pktin.body[i]));
407 debug(("\r\n"));
408#endif
409 zlib_decompress_block(pktin.body-1, pktin.length+1,
410 &decompblk, &decomplen);
411
412 if (pktin.maxlen < st->pad + decomplen) {
413 pktin.maxlen = st->pad + decomplen;
dcbde236 414 pktin.data = srealloc(pktin.data, pktin.maxlen+APIEXTRA);
58298665 415 pktin.body = pktin.data + st->pad + 1;
4ba9b64b 416 if (!pktin.data)
417 fatalbox("Out of memory");
418 }
419
420 memcpy(pktin.body-1, decompblk, decomplen);
dcbde236 421 sfree(decompblk);
4ba9b64b 422 pktin.length = decomplen-1;
423#if 0
424 debug(("Packet payload post-decompression:\n"));
425 for (i = -1; i < pktin.length; i++)
426 debug((" %02x", (unsigned char)pktin.body[i]));
427 debug(("\r\n"));
428#endif
429 }
430
e5574168 431 if (pktin.type == SSH1_SMSG_STDOUT_DATA ||
432 pktin.type == SSH1_SMSG_STDERR_DATA ||
433 pktin.type == SSH1_MSG_DEBUG ||
18515c51 434 pktin.type == SSH1_SMSG_AUTH_TIS_CHALLENGE ||
435 pktin.type == SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
fb09bf1c 436 long strlen = GET_32BIT(pktin.body);
8d5de777 437 if (strlen + 4 != pktin.length) {
438 bombout(("Received data packet with bogus string length"));
439 crReturn(0);
440 }
fb09bf1c 441 }
442
4ba9b64b 443 pktin.type = pktin.body[-1];
444
e5574168 445 if (pktin.type == SSH1_MSG_DEBUG) {
fb09bf1c 446 /* log debug message */
447 char buf[80];
448 int strlen = GET_32BIT(pktin.body);
449 strcpy(buf, "Remote: ");
450 if (strlen > 70) strlen = 70;
451 memcpy(buf+8, pktin.body+4, strlen);
452 buf[8+strlen] = '\0';
453 logevent(buf);
454 goto next_packet;
e5574168 455 } else if (pktin.type == SSH1_MSG_IGNORE) {
fb09bf1c 456 /* do nothing */
457 goto next_packet;
458 }
459
460 crFinish(0);
461}
462
e5574168 463static int ssh2_rdpkt(unsigned char **data, int *datalen)
464{
960e736a 465 struct rdpkt2_state_tag *st = &rdpkt2_state;
e5574168 466
467 crBegin;
468
469next_packet:
e5574168 470 pktin.type = 0;
471 pktin.length = 0;
960e736a 472 if (sccipher)
473 st->cipherblk = sccipher->blksize;
e5574168 474 else
960e736a 475 st->cipherblk = 8;
476 if (st->cipherblk < 8)
477 st->cipherblk = 8;
478
479 if (pktin.maxlen < st->cipherblk) {
480 pktin.maxlen = st->cipherblk;
dcbde236 481 pktin.data = (pktin.data == NULL ? smalloc(st->cipherblk+APIEXTRA) :
482 srealloc(pktin.data, st->cipherblk+APIEXTRA));
e5574168 483 if (!pktin.data)
484 fatalbox("Out of memory");
485 }
486
487 /*
488 * Acquire and decrypt the first block of the packet. This will
489 * contain the length and padding details.
490 */
960e736a 491 for (st->i = st->len = 0; st->i < st->cipherblk; st->i++) {
e5574168 492 while ((*datalen) == 0)
960e736a 493 crReturn(st->cipherblk-st->i);
494 pktin.data[st->i] = *(*data)++;
e5574168 495 (*datalen)--;
496 }
497#ifdef FWHACK
498 if (!memcmp(pktin.data, "Remo", 4)) {/* "Remo"te server has closed ... */
499 /* FIXME */
500 }
501#endif
502 if (sccipher)
960e736a 503 sccipher->decrypt(pktin.data, st->cipherblk);
e5574168 504
505 /*
506 * Now get the length and padding figures.
507 */
960e736a 508 st->len = GET_32BIT(pktin.data);
509 st->pad = pktin.data[4];
e5574168 510
511 /*
512 * This enables us to deduce the payload length.
513 */
960e736a 514 st->payload = st->len - st->pad - 1;
e5574168 515
960e736a 516 pktin.length = st->payload + 5;
e5574168 517
518 /*
519 * So now we can work out the total packet length.
520 */
960e736a 521 st->packetlen = st->len + 4;
522 st->maclen = scmac ? scmac->len : 0;
e5574168 523
524 /*
525 * Adjust memory allocation if packet is too big.
526 */
960e736a 527 if (pktin.maxlen < st->packetlen+st->maclen) {
528 pktin.maxlen = st->packetlen+st->maclen;
dcbde236 529 pktin.data = (pktin.data == NULL ? smalloc(pktin.maxlen+APIEXTRA) :
530 srealloc(pktin.data, pktin.maxlen+APIEXTRA));
e5574168 531 if (!pktin.data)
532 fatalbox("Out of memory");
533 }
534
535 /*
536 * Read and decrypt the remainder of the packet.
537 */
960e736a 538 for (st->i = st->cipherblk; st->i < st->packetlen + st->maclen; st->i++) {
e5574168 539 while ((*datalen) == 0)
960e736a 540 crReturn(st->packetlen + st->maclen - st->i);
541 pktin.data[st->i] = *(*data)++;
e5574168 542 (*datalen)--;
543 }
544 /* Decrypt everything _except_ the MAC. */
545 if (sccipher)
960e736a 546 sccipher->decrypt(pktin.data + st->cipherblk,
547 st->packetlen - st->cipherblk);
e5574168 548
7cca0d81 549#if 0
960e736a 550 debug(("Got packet len=%d pad=%d\r\n", st->len, st->pad));
551 for (st->i = 0; st->i < st->packetlen; st->i++)
552 debug((" %02x", (unsigned char)pktin.data[st->i]));
d39f364a 553 debug(("\r\n"));
7cca0d81 554#endif
d39f364a 555
e5574168 556 /*
557 * Check the MAC.
558 */
960e736a 559 if (scmac && !scmac->verify(pktin.data, st->len+4, st->incoming_sequence)) {
8d5de777 560 bombout(("Incorrect MAC received on packet"));
561 crReturn(0);
562 }
960e736a 563 st->incoming_sequence++; /* whether or not we MACed */
e5574168 564
4ba9b64b 565 /*
566 * Decompress packet payload.
567 */
568 {
569 unsigned char *newpayload;
570 int newlen;
571 if (sccomp && sccomp->decompress(pktin.data+5, pktin.length-5,
572 &newpayload, &newlen)) {
573 if (pktin.maxlen < newlen+5) {
574 pktin.maxlen = newlen+5;
dcbde236 575 pktin.data = (pktin.data == NULL ? smalloc(pktin.maxlen+APIEXTRA) :
576 srealloc(pktin.data, pktin.maxlen+APIEXTRA));
4ba9b64b 577 if (!pktin.data)
578 fatalbox("Out of memory");
579 }
580 pktin.length = 5 + newlen;
581 memcpy(pktin.data+5, newpayload, newlen);
582#if 0
583 debug(("Post-decompression payload:\r\n"));
584 for (st->i = 0; st->i < newlen; st->i++)
585 debug((" %02x", (unsigned char)pktin.data[5+st->i]));
586 debug(("\r\n"));
587#endif
588
dcbde236 589 sfree(newpayload);
4ba9b64b 590 }
591 }
592
e5574168 593 pktin.savedpos = 6;
594 pktin.type = pktin.data[5];
e5574168 595
7cca0d81 596 if (pktin.type == SSH2_MSG_IGNORE || pktin.type == SSH2_MSG_DEBUG)
597 goto next_packet; /* FIXME: print DEBUG message */
e5574168 598
599 crFinish(0);
600}
601
4ba9b64b 602static void ssh1_pktout_size(int len) {
374330e2 603 int pad, biglen;
604
605 len += 5; /* type and CRC */
606 pad = 8 - (len%8);
607 biglen = len + pad;
608
609 pktout.length = len-5;
610 if (pktout.maxlen < biglen) {
611 pktout.maxlen = biglen;
8f203108 612#ifdef MSCRYPTOAPI
fb09bf1c 613 /* Allocate enough buffer space for extra block
8f203108 614 * for MS CryptEncrypt() */
dcbde236 615 pktout.data = (pktout.data == NULL ? smalloc(biglen+12) :
616 srealloc(pktout.data, biglen+12));
8f203108 617#else
dcbde236 618 pktout.data = (pktout.data == NULL ? smalloc(biglen+4) :
619 srealloc(pktout.data, biglen+4));
8f203108 620#endif
374330e2 621 if (!pktout.data)
622 fatalbox("Out of memory");
623 }
4ba9b64b 624 pktout.body = pktout.data+4+pad+1;
625}
374330e2 626
4ba9b64b 627static void s_wrpkt_start(int type, int len) {
628 ssh1_pktout_size(len);
374330e2 629 pktout.type = type;
374330e2 630}
631
632static void s_wrpkt(void) {
633 int pad, len, biglen, i;
634 unsigned long crc;
635
4ba9b64b 636 pktout.body[-1] = pktout.type;
637
638 if (ssh1_compressing) {
639 unsigned char *compblk;
640 int complen;
641#if 0
642 debug(("Packet payload pre-compression:\n"));
643 for (i = -1; i < pktout.length; i++)
644 debug((" %02x", (unsigned char)pktout.body[i]));
645 debug(("\r\n"));
646#endif
647 zlib_compress_block(pktout.body-1, pktout.length+1,
648 &compblk, &complen);
649 ssh1_pktout_size(complen-1);
650 memcpy(pktout.body-1, compblk, complen);
dcbde236 651 sfree(compblk);
4ba9b64b 652#if 0
653 debug(("Packet payload post-compression:\n"));
654 for (i = -1; i < pktout.length; i++)
655 debug((" %02x", (unsigned char)pktout.body[i]));
656 debug(("\r\n"));
657#endif
658 }
659
374330e2 660 len = pktout.length + 5; /* type and CRC */
661 pad = 8 - (len%8);
662 biglen = len + pad;
663
374330e2 664 for (i=0; i<pad; i++)
665 pktout.data[i+4] = random_byte();
666 crc = crc32(pktout.data+4, biglen-4);
fb09bf1c 667 PUT_32BIT(pktout.data+biglen, crc);
668 PUT_32BIT(pktout.data, len);
374330e2 669
698a5108 670#if 0
671 debug(("Sending packet len=%d\r\n", biglen+4));
672 for (i = 0; i < biglen+4; i++)
673 debug((" %02x", (unsigned char)pktout.data[i]));
674 debug(("\r\n"));
675#endif
374330e2 676 if (cipher)
677 cipher->encrypt(pktout.data+4, biglen);
678
8df7a775 679 sk_write(s, pktout.data, biglen+4);
374330e2 680}
681
fb09bf1c 682/*
683 * Construct a packet with the specified contents and
684 * send it to the server.
685 */
686static void send_packet(int pkttype, ...)
687{
688 va_list args;
689 unsigned char *p, *argp, argchar;
690 unsigned long argint;
691 int pktlen, argtype, arglen;
7cca0d81 692 Bignum bn;
fb09bf1c 693
694 pktlen = 0;
695 va_start(args, pkttype);
696 while ((argtype = va_arg(args, int)) != PKT_END) {
697 switch (argtype) {
698 case PKT_INT:
699 (void) va_arg(args, int);
700 pktlen += 4;
701 break;
702 case PKT_CHAR:
703 (void) va_arg(args, char);
704 pktlen++;
705 break;
706 case PKT_DATA:
707 (void) va_arg(args, unsigned char *);
708 arglen = va_arg(args, int);
709 pktlen += arglen;
710 break;
711 case PKT_STR:
712 argp = va_arg(args, unsigned char *);
713 arglen = strlen(argp);
714 pktlen += 4 + arglen;
715 break;
7cca0d81 716 case PKT_BIGNUM:
717 bn = va_arg(args, Bignum);
5c58ad2d 718 pktlen += ssh1_bignum_length(bn);
7cca0d81 719 break;
fb09bf1c 720 default:
721 assert(0);
722 }
723 }
724 va_end(args);
725
726 s_wrpkt_start(pkttype, pktlen);
727 p = pktout.body;
728
729 va_start(args, pkttype);
730 while ((argtype = va_arg(args, int)) != PKT_END) {
731 switch (argtype) {
732 case PKT_INT:
733 argint = va_arg(args, int);
734 PUT_32BIT(p, argint);
735 p += 4;
736 break;
737 case PKT_CHAR:
738 argchar = va_arg(args, unsigned char);
739 *p = argchar;
740 p++;
741 break;
742 case PKT_DATA:
743 argp = va_arg(args, unsigned char *);
744 arglen = va_arg(args, int);
745 memcpy(p, argp, arglen);
746 p += arglen;
747 break;
748 case PKT_STR:
749 argp = va_arg(args, unsigned char *);
750 arglen = strlen(argp);
751 PUT_32BIT(p, arglen);
752 memcpy(p + 4, argp, arglen);
753 p += 4 + arglen;
754 break;
7cca0d81 755 case PKT_BIGNUM:
756 bn = va_arg(args, Bignum);
5c58ad2d 757 p += ssh1_write_bignum(p, bn);
7cca0d81 758 break;
fb09bf1c 759 }
760 }
761 va_end(args);
762
763 s_wrpkt();
764}
765
9697bfd2 766static int ssh_versioncmp(char *a, char *b) {
767 char *ae, *be;
768 unsigned long av, bv;
769
43aa02a7 770 av = strtoul(a, &ae, 10);
771 bv = strtoul(b, &be, 10);
9697bfd2 772 if (av != bv) return (av < bv ? -1 : +1);
773 if (*ae == '.') ae++;
774 if (*be == '.') be++;
43aa02a7 775 av = strtoul(ae, &ae, 10);
776 bv = strtoul(be, &be, 10);
9697bfd2 777 if (av != bv) return (av < bv ? -1 : +1);
778 return 0;
779}
780
e5574168 781
782/*
783 * Utility routine for putting an SSH-protocol `string' into a SHA
784 * state.
785 */
786#include <stdio.h>
75cab814 787static void sha_string(SHA_State *s, void *str, int len) {
e5574168 788 unsigned char lenblk[4];
e5574168 789 PUT_32BIT(lenblk, len);
e5574168 790 SHA_Bytes(s, lenblk, 4);
e5574168 791 SHA_Bytes(s, str, len);
792}
793
7cca0d81 794/*
795 * SSH2 packet construction functions.
796 */
75cab814 797static void ssh2_pkt_adddata(void *data, int len) {
7cca0d81 798 pktout.length += len;
799 if (pktout.maxlen < pktout.length) {
800 pktout.maxlen = pktout.length + 256;
dcbde236 801 pktout.data = (pktout.data == NULL ? smalloc(pktout.maxlen+APIEXTRA) :
802 srealloc(pktout.data, pktout.maxlen+APIEXTRA));
7cca0d81 803 if (!pktout.data)
804 fatalbox("Out of memory");
805 }
806 memcpy(pktout.data+pktout.length-len, data, len);
807}
75cab814 808static void ssh2_pkt_addbyte(unsigned char byte) {
7cca0d81 809 ssh2_pkt_adddata(&byte, 1);
810}
75cab814 811static void ssh2_pkt_init(int pkt_type) {
7cca0d81 812 pktout.length = 5;
813 ssh2_pkt_addbyte((unsigned char)pkt_type);
814}
75cab814 815static void ssh2_pkt_addbool(unsigned char value) {
7cca0d81 816 ssh2_pkt_adddata(&value, 1);
817}
75cab814 818static void ssh2_pkt_adduint32(unsigned long value) {
7cca0d81 819 unsigned char x[4];
820 PUT_32BIT(x, value);
821 ssh2_pkt_adddata(x, 4);
822}
75cab814 823static void ssh2_pkt_addstring_start(void) {
7cca0d81 824 ssh2_pkt_adduint32(0);
825 pktout.savedpos = pktout.length;
826}
75cab814 827static void ssh2_pkt_addstring_str(char *data) {
7cca0d81 828 ssh2_pkt_adddata(data, strlen(data));
829 PUT_32BIT(pktout.data + pktout.savedpos - 4,
830 pktout.length - pktout.savedpos);
831}
75cab814 832static void ssh2_pkt_addstring_data(char *data, int len) {
7cca0d81 833 ssh2_pkt_adddata(data, len);
834 PUT_32BIT(pktout.data + pktout.savedpos - 4,
835 pktout.length - pktout.savedpos);
836}
75cab814 837static void ssh2_pkt_addstring(char *data) {
7cca0d81 838 ssh2_pkt_addstring_start();
839 ssh2_pkt_addstring_str(data);
840}
75cab814 841static char *ssh2_mpint_fmt(Bignum b, int *len) {
7cca0d81 842 unsigned char *p;
843 int i, n = b[0];
dcbde236 844 p = smalloc(n * 2 + 1);
7cca0d81 845 if (!p)
846 fatalbox("out of memory");
847 p[0] = 0;
848 for (i = 0; i < n; i++) {
849 p[i*2+1] = (b[n-i] >> 8) & 0xFF;
850 p[i*2+2] = (b[n-i] ) & 0xFF;
851 }
852 i = 0;
853 while (p[i] == 0 && (p[i+1] & 0x80) == 0)
854 i++;
855 memmove(p, p+i, n*2+1-i);
856 *len = n*2+1-i;
857 return p;
858}
75cab814 859static void ssh2_pkt_addmp(Bignum b) {
7cca0d81 860 unsigned char *p;
861 int len;
862 p = ssh2_mpint_fmt(b, &len);
863 ssh2_pkt_addstring_start();
864 ssh2_pkt_addstring_data(p, len);
dcbde236 865 sfree(p);
7cca0d81 866}
75cab814 867static void ssh2_pkt_send(void) {
7cca0d81 868 int cipherblk, maclen, padding, i;
869 static unsigned long outgoing_sequence = 0;
870
871 /*
4ba9b64b 872 * Compress packet payload.
873 */
874#if 0
875 debug(("Pre-compression payload:\r\n"));
876 for (i = 5; i < pktout.length; i++)
877 debug((" %02x", (unsigned char)pktout.data[i]));
878 debug(("\r\n"));
879#endif
880 {
881 unsigned char *newpayload;
882 int newlen;
883 if (cscomp && cscomp->compress(pktout.data+5, pktout.length-5,
884 &newpayload, &newlen)) {
885 pktout.length = 5;
886 ssh2_pkt_adddata(newpayload, newlen);
dcbde236 887 sfree(newpayload);
4ba9b64b 888 }
889 }
890
891 /*
7cca0d81 892 * Add padding. At least four bytes, and must also bring total
893 * length (minus MAC) up to a multiple of the block size.
894 */
895 cipherblk = cipher ? cipher->blksize : 8; /* block size */
896 cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */
897 padding = 4;
898 padding += (cipherblk - (pktout.length + padding) % cipherblk) % cipherblk;
899 pktout.data[4] = padding;
900 for (i = 0; i < padding; i++)
901 pktout.data[pktout.length + i] = random_byte();
902 PUT_32BIT(pktout.data, pktout.length + padding - 4);
903 if (csmac)
904 csmac->generate(pktout.data, pktout.length + padding,
905 outgoing_sequence);
906 outgoing_sequence++; /* whether or not we MACed */
907
908#if 0
909 debug(("Sending packet len=%d\r\n", pktout.length+padding));
910 for (i = 0; i < pktout.length+padding; i++)
911 debug((" %02x", (unsigned char)pktout.data[i]));
912 debug(("\r\n"));
913#endif
914
915 if (cscipher)
916 cscipher->encrypt(pktout.data, pktout.length + padding);
917 maclen = csmac ? csmac->len : 0;
918
8df7a775 919 sk_write(s, pktout.data, pktout.length + padding + maclen);
7cca0d81 920}
921
922#if 0
923void bndebug(char *string, Bignum b) {
924 unsigned char *p;
925 int i, len;
926 p = ssh2_mpint_fmt(b, &len);
927 debug(("%s", string));
928 for (i = 0; i < len; i++)
929 debug((" %02x", p[i]));
930 debug(("\r\n"));
dcbde236 931 sfree(p);
7cca0d81 932}
933#endif
934
75cab814 935static void sha_mpint(SHA_State *s, Bignum b) {
7cca0d81 936 unsigned char *p;
937 int len;
938 p = ssh2_mpint_fmt(b, &len);
939 sha_string(s, p, len);
dcbde236 940 sfree(p);
7cca0d81 941}
942
943/*
944 * SSH2 packet decode functions.
945 */
75cab814 946static unsigned long ssh2_pkt_getuint32(void) {
7cca0d81 947 unsigned long value;
948 if (pktin.length - pktin.savedpos < 4)
949 return 0; /* arrgh, no way to decline (FIXME?) */
950 value = GET_32BIT(pktin.data+pktin.savedpos);
951 pktin.savedpos += 4;
952 return value;
953}
75cab814 954static void ssh2_pkt_getstring(char **p, int *length) {
7cca0d81 955 *p = NULL;
956 if (pktin.length - pktin.savedpos < 4)
957 return;
958 *length = GET_32BIT(pktin.data+pktin.savedpos);
959 pktin.savedpos += 4;
960 if (pktin.length - pktin.savedpos < *length)
961 return;
962 *p = pktin.data+pktin.savedpos;
963 pktin.savedpos += *length;
964}
75cab814 965static Bignum ssh2_pkt_getmp(void) {
7cca0d81 966 char *p;
967 int i, j, length;
968 Bignum b;
969
970 ssh2_pkt_getstring(&p, &length);
971 if (!p)
972 return NULL;
8d5de777 973 if (p[0] & 0x80) {
974 bombout(("internal error: Can't handle negative mpints"));
975 return NULL;
976 }
7cca0d81 977 b = newbn((length+1)/2);
978 for (i = 0; i < length; i++) {
979 j = length - 1 - i;
980 if (j & 1)
981 b[j/2+1] |= ((unsigned char)p[i]) << 8;
982 else
983 b[j/2+1] |= ((unsigned char)p[i]);
984 }
6b4e00ee 985 while (b[0] > 1 && b[b[0]] == 0) b[0]--;
7cca0d81 986 return b;
987}
988
8df7a775 989static int do_ssh_init(unsigned char c) {
990 static char *vsp;
991 static char version[10];
992 static char vstring[80];
993 static char vlog[sizeof(vstring)+20];
994 static int i;
374330e2 995
8df7a775 996 crBegin;
997
998 /* Search for the string "SSH-" in the input. */
374330e2 999 i = 0;
8df7a775 1000 while (1) {
1001 static const int transS[] = { 1, 2, 2, 1 };
1002 static const int transH[] = { 0, 0, 3, 0 };
1003 static const int transminus[] = { 0, 0, 0, -1 };
1004 if (c == 'S') i = transS[i];
1005 else if (c == 'H') i = transH[i];
1006 else if (c == '-') i = transminus[i];
374330e2 1007 else i = 0;
8df7a775 1008 if (i < 0)
1009 break;
1010 crReturn(1); /* get another character */
374330e2 1011 }
8df7a775 1012
c5e9c988 1013 strcpy(vstring, "SSH-");
1014 vsp = vstring+4;
374330e2 1015 i = 0;
1016 while (1) {
8df7a775 1017 crReturn(1); /* get another char */
c5e9c988 1018 if (vsp < vstring+sizeof(vstring)-1)
1019 *vsp++ = c;
374330e2 1020 if (i >= 0) {
1021 if (c == '-') {
1022 version[i] = '\0';
1023 i = -1;
1024 } else if (i < sizeof(version)-1)
1025 version[i++] = c;
1026 }
1027 else if (c == '\n')
1028 break;
1029 }
1030
db7d555c 1031 ssh_agentfwd_enabled = FALSE;
960e736a 1032 rdpkt2_state.incoming_sequence = 0;
1033
c5e9c988 1034 *vsp = 0;
1035 sprintf(vlog, "Server version: %s", vstring);
1036 vlog[strcspn(vlog, "\r\n")] = '\0';
1037 logevent(vlog);
1038
adf799dd 1039 /*
1040 * Server version "1.99" means we can choose whether we use v1
1041 * or v2 protocol. Choice is based on cfg.sshprot.
1042 */
1043 if (ssh_versioncmp(version, cfg.sshprot == 1 ? "2.0" : "1.99") >= 0) {
e5574168 1044 /*
1045 * This is a v2 server. Begin v2 protocol.
1046 */
1047 char *verstring = "SSH-2.0-PuTTY";
0db56f73 1048 SHA_Init(&exhashbase);
e5574168 1049 /*
1050 * Hash our version string and their version string.
1051 */
0db56f73 1052 sha_string(&exhashbase, verstring, strlen(verstring));
1053 sha_string(&exhashbase, vstring, strcspn(vstring, "\r\n"));
e5574168 1054 sprintf(vstring, "%s\n", verstring);
1055 sprintf(vlog, "We claim version: %s", verstring);
1056 logevent(vlog);
1057 logevent("Using SSH protocol version 2");
8df7a775 1058 sk_write(s, vstring, strlen(vstring));
e5574168 1059 ssh_protocol = ssh2_protocol;
6abbf9e3 1060 ssh_version = 2;
e5574168 1061 s_rdpkt = ssh2_rdpkt;
1062 } else {
1063 /*
1064 * This is a v1 server. Begin v1 protocol.
1065 */
1066 sprintf(vstring, "SSH-%s-PuTTY\n",
1067 (ssh_versioncmp(version, "1.5") <= 0 ? version : "1.5"));
1068 sprintf(vlog, "We claim version: %s", vstring);
1069 vlog[strcspn(vlog, "\r\n")] = '\0';
1070 logevent(vlog);
1071 logevent("Using SSH protocol version 1");
8df7a775 1072 sk_write(s, vstring, strlen(vstring));
e5574168 1073 ssh_protocol = ssh1_protocol;
6abbf9e3 1074 ssh_version = 1;
e5574168 1075 s_rdpkt = ssh1_rdpkt;
1076 }
3687d221 1077 ssh_state = SSH_STATE_BEFORE_SIZE;
8df7a775 1078
1079 crFinish(0);
1080}
1081
1082static void ssh_gotdata(unsigned char *data, int datalen)
1083{
1084 crBegin;
1085
1086 /*
1087 * To begin with, feed the characters one by one to the
1088 * protocol initialisation / selection function do_ssh_init().
1089 * When that returns 0, we're done with the initial greeting
1090 * exchange and can move on to packet discipline.
1091 */
1092 while (1) {
1093 int ret;
1094 if (datalen == 0)
1095 crReturnV; /* more data please */
1096 ret = do_ssh_init(*data);
1097 data++; datalen--;
1098 if (ret == 0)
1099 break;
1100 }
1101
1102 /*
1103 * We emerge from that loop when the initial negotiation is
1104 * over and we have selected an s_rdpkt function. Now pass
1105 * everything to s_rdpkt, and then pass the resulting packets
1106 * to the proper protocol handler.
1107 */
1108 if (datalen == 0)
1109 crReturnV;
1110 while (1) {
1111 while (datalen > 0) {
1112 if ( s_rdpkt(&data, &datalen) == 0 ) {
1113 ssh_protocol(NULL, 0, 1);
1114 if (ssh_state == SSH_STATE_CLOSED) {
1115 return;
1116 }
1117 }
1118 }
1119 crReturnV;
1120 }
1121 crFinishV;
1122}
1123
340cf649 1124static int ssh_receive(Socket skt, int urgent, char *data, int len) {
8df7a775 1125 if (!len) {
1126 /* Connection has closed. */
1127 sk_close(s);
1128 s = NULL;
1129 return 0;
1130 }
1131 ssh_gotdata (data, len);
3257deae 1132 if (ssh_state == SSH_STATE_CLOSED) {
1133 if (s) {
1134 sk_close(s);
1135 s = NULL;
1136 }
1137 return 0;
1138 }
fef97f43 1139 return 1;
374330e2 1140}
1141
fb09bf1c 1142/*
8df7a775 1143 * Connect to specified host and port.
1144 * Returns an error message, or NULL on success.
1145 * Also places the canonical host name into `realhost'.
1146 */
1147static char *connect_to_host(char *host, int port, char **realhost)
1148{
1149 SockAddr addr;
1150 char *err;
1151#ifdef FWHACK
1152 char *FWhost;
1153 int FWport;
1154#endif
1155
dcbde236 1156 savedhost = smalloc(1+strlen(host));
8df7a775 1157 if (!savedhost)
1158 fatalbox("Out of memory");
1159 strcpy(savedhost, host);
1160
1161 if (port < 0)
1162 port = 22; /* default ssh port */
1163 savedport = port;
1164
1165#ifdef FWHACK
1166 FWhost = host;
1167 FWport = port;
1168 host = FWSTR;
1169 port = 23;
1170#endif
1171
1172 /*
1173 * Try to find host.
1174 */
1175 addr = sk_namelookup(host, realhost);
1176 if ( (err = sk_addr_error(addr)) )
1177 return err;
1178
1179#ifdef FWHACK
1180 *realhost = FWhost;
1181#endif
1182
1183 /*
1184 * Open socket.
1185 */
1186 s = sk_new(addr, port, ssh_receive);
1187 if ( (err = sk_socket_error(s)) )
1188 return err;
1189
1190#ifdef FWHACK
1191 sk_write(s, "connect ", 8);
1192 sk_write(s, FWhost, strlen(FWhost));
1193 {
1194 char buf[20];
1195 sprintf(buf, " %d\n", FWport);
1196 sk_write(s, buf, strlen(buf));
1197 }
1198#endif
1199
1200 return NULL;
1201}
1202
1203/*
fb09bf1c 1204 * Handle the key exchange and user authentication phases.
1205 */
e5574168 1206static int do_ssh1_login(unsigned char *in, int inlen, int ispkt)
fb09bf1c 1207{
374330e2 1208 int i, j, len;
374330e2 1209 unsigned char *rsabuf, *keystr1, *keystr2;
1210 unsigned char cookie[8];
1211 struct RSAKey servkey, hostkey;
1212 struct MD5Context md5c;
ccbfb941 1213 static unsigned long supported_ciphers_mask, supported_auths_mask;
7cca0d81 1214 static int tried_publickey;
1215 static unsigned char session_id[16];
bea1ef5f 1216 int cipher_type;
b585ec46 1217 static char username[100];
374330e2 1218
374330e2 1219 crBegin;
1220
fb09bf1c 1221 if (!ispkt) crWaitUntil(ispkt);
374330e2 1222
8d5de777 1223 if (pktin.type != SSH1_SMSG_PUBLIC_KEY) {
1224 bombout(("Public key packet not received"));
1225 crReturn(0);
1226 }
374330e2 1227
c5e9c988 1228 logevent("Received public keys");
374330e2 1229
c5e9c988 1230 memcpy(cookie, pktin.body, 8);
374330e2 1231
7cca0d81 1232 i = makekey(pktin.body+8, &servkey, &keystr1, 0);
1233 j = makekey(pktin.body+8+i, &hostkey, &keystr2, 0);
374330e2 1234
c5e9c988 1235 /*
1c2a93c4 1236 * Log the host key fingerprint.
c5e9c988 1237 */
c5e9c988 1238 {
1239 char logmsg[80];
1c2a93c4 1240 logevent("Host key fingerprint is:");
c5e9c988 1241 strcpy(logmsg, " ");
1c2a93c4 1242 hostkey.comment = NULL;
1243 rsa_fingerprint(logmsg+strlen(logmsg), sizeof(logmsg)-strlen(logmsg),
1244 &hostkey);
c5e9c988 1245 logevent(logmsg);
1246 }
1247
fb09bf1c 1248 supported_ciphers_mask = GET_32BIT(pktin.body+12+i+j);
1249 supported_auths_mask = GET_32BIT(pktin.body+16+i+j);
bea1ef5f 1250
c5e9c988 1251 MD5Init(&md5c);
374330e2 1252 MD5Update(&md5c, keystr2, hostkey.bytes);
1253 MD5Update(&md5c, keystr1, servkey.bytes);
1254 MD5Update(&md5c, pktin.body, 8);
374330e2 1255 MD5Final(session_id, &md5c);
1256
1257 for (i=0; i<32; i++)
1258 session_key[i] = random_byte();
1259
1260 len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes);
1261
dcbde236 1262 rsabuf = smalloc(len);
374330e2 1263 if (!rsabuf)
1264 fatalbox("Out of memory");
1265
89ee5268 1266 /*
1267 * Verify the host key.
1268 */
1269 {
1270 /*
1271 * First format the key into a string.
1272 */
1273 int len = rsastr_len(&hostkey);
d5859615 1274 char fingerprint[100];
dcbde236 1275 char *keystr = smalloc(len);
89ee5268 1276 if (!keystr)
1277 fatalbox("Out of memory");
1278 rsastr_fmt(keystr, &hostkey);
d5859615 1279 rsa_fingerprint(fingerprint, sizeof(fingerprint), &hostkey);
d4857987 1280 verify_ssh_host_key(savedhost, savedport, "rsa", keystr, fingerprint);
dcbde236 1281 sfree(keystr);
89ee5268 1282 }
374330e2 1283
1284 for (i=0; i<32; i++) {
1285 rsabuf[i] = session_key[i];
1286 if (i < 16)
1287 rsabuf[i] ^= session_id[i];
1288 }
1289
1290 if (hostkey.bytes > servkey.bytes) {
1291 rsaencrypt(rsabuf, 32, &servkey);
1292 rsaencrypt(rsabuf, servkey.bytes, &hostkey);
1293 } else {
1294 rsaencrypt(rsabuf, 32, &hostkey);
1295 rsaencrypt(rsabuf, hostkey.bytes, &servkey);
1296 }
1297
c5e9c988 1298 logevent("Encrypted session key");
1299
bea1ef5f 1300 cipher_type = cfg.cipher == CIPHER_BLOWFISH ? SSH_CIPHER_BLOWFISH :
9697bfd2 1301 cfg.cipher == CIPHER_DES ? SSH_CIPHER_DES :
bea1ef5f 1302 SSH_CIPHER_3DES;
1303 if ((supported_ciphers_mask & (1 << cipher_type)) == 0) {
1304 c_write("Selected cipher not supported, falling back to 3DES\r\n", 53);
1305 cipher_type = SSH_CIPHER_3DES;
1306 }
c5e9c988 1307 switch (cipher_type) {
1308 case SSH_CIPHER_3DES: logevent("Using 3DES encryption"); break;
1309 case SSH_CIPHER_DES: logevent("Using single-DES encryption"); break;
1310 case SSH_CIPHER_BLOWFISH: logevent("Using Blowfish encryption"); break;
1311 }
bea1ef5f 1312
e5574168 1313 send_packet(SSH1_CMSG_SESSION_KEY,
fb09bf1c 1314 PKT_CHAR, cipher_type,
1315 PKT_DATA, cookie, 8,
1316 PKT_CHAR, (len*8) >> 8, PKT_CHAR, (len*8) & 0xFF,
1317 PKT_DATA, rsabuf, len,
1318 PKT_INT, 0,
1319 PKT_END);
1320
c5e9c988 1321 logevent("Trying to enable encryption...");
374330e2 1322
dcbde236 1323 sfree(rsabuf);
374330e2 1324
5e8358ad 1325 cipher = cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 :
9697bfd2 1326 cipher_type == SSH_CIPHER_DES ? &ssh_des :
bea1ef5f 1327 &ssh_3des;
374330e2 1328 cipher->sesskey(session_key);
1329
fb09bf1c 1330 crWaitUntil(ispkt);
374330e2 1331
8d5de777 1332 if (pktin.type != SSH1_SMSG_SUCCESS) {
1333 bombout(("Encryption not successfully enabled"));
1334 crReturn(0);
1335 }
374330e2 1336
c5e9c988 1337 logevent("Successfully started encryption");
1338
374330e2 1339 fflush(stdout);
1340 {
374330e2 1341 static int pos = 0;
1342 static char c;
67779be7 1343 if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
374330e2 1344 c_write("login as: ", 10);
67779be7 1345 ssh_send_ok = 1;
374330e2 1346 while (pos >= 0) {
fb09bf1c 1347 crWaitUntil(!ispkt);
374330e2 1348 while (inlen--) switch (c = *in++) {
1349 case 10: case 13:
1350 username[pos] = 0;
1351 pos = -1;
1352 break;
1353 case 8: case 127:
1354 if (pos > 0) {
1355 c_write("\b \b", 3);
1356 pos--;
1357 }
1358 break;
1359 case 21: case 27:
1360 while (pos > 0) {
1361 c_write("\b \b", 3);
1362 pos--;
1363 }
1364 break;
1365 case 3: case 4:
1366 random_save_seed();
1367 exit(0);
1368 break;
1369 default:
40d24aa6 1370 if (((c >= ' ' && c <= '~') ||
1371 ((unsigned char)c >= 160)) && pos < 40) {
374330e2 1372 username[pos++] = c;
1373 c_write(&c, 1);
1374 }
1375 break;
1376 }
1377 }
1378 c_write("\r\n", 2);
1379 username[strcspn(username, "\n\r")] = '\0';
1380 } else {
374330e2 1381 strncpy(username, cfg.username, 99);
1382 username[99] = '\0';
374330e2 1383 }
fb09bf1c 1384
e5574168 1385 send_packet(SSH1_CMSG_USER, PKT_STR, username, PKT_END);
c5e9c988 1386 {
3c8e959b 1387 char userlog[22+sizeof(username)];
c5e9c988 1388 sprintf(userlog, "Sent username \"%s\"", username);
1389 logevent(userlog);
3c8e959b 1390 if (flags & FLAG_INTERACTIVE &&
1391 (!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) {
1392 strcat(userlog, "\r\n");
1393 c_write(userlog, strlen(userlog));
1394 }
c5e9c988 1395 }
374330e2 1396 }
1397
fb09bf1c 1398 crWaitUntil(ispkt);
374330e2 1399
7cca0d81 1400 tried_publickey = 0;
1401
e5574168 1402 while (pktin.type == SSH1_SMSG_FAILURE) {
374330e2 1403 static char password[100];
a52f067e 1404 static char prompt[200];
374330e2 1405 static int pos;
1406 static char c;
ccbfb941 1407 static int pwpkt_type;
ccbfb941 1408 /*
1409 * Show password prompt, having first obtained it via a TIS
18515c51 1410 * or CryptoCard exchange if we're doing TIS or CryptoCard
1411 * authentication.
ccbfb941 1412 */
e5574168 1413 pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
5c58ad2d 1414 if (agent_exists()) {
1415 /*
1416 * Attempt RSA authentication using Pageant.
1417 */
1418 static unsigned char request[5], *response, *p;
1419 static int responselen;
1420 static int i, nkeys;
1421 static int authed = FALSE;
1422 void *r;
1423
1424 logevent("Pageant is running. Requesting keys.");
1425
1426 /* Request the keys held by the agent. */
1427 PUT_32BIT(request, 1);
1428 request[4] = SSH_AGENTC_REQUEST_RSA_IDENTITIES;
1429 agent_query(request, 5, &r, &responselen);
1430 response = (unsigned char *)r;
1431 if (response) {
1432 p = response + 5;
1433 nkeys = GET_32BIT(p); p += 4;
1434 { char buf[64]; sprintf(buf, "Pageant has %d keys", nkeys);
1435 logevent(buf); }
1436 for (i = 0; i < nkeys; i++) {
1437 static struct RSAKey key;
1438 static Bignum challenge;
b8bb811a 1439 static char *commentp;
1440 static int commentlen;
5c58ad2d 1441
1442 { char buf[64]; sprintf(buf, "Trying Pageant key #%d", i);
1443 logevent(buf); }
1444 p += 4;
1445 p += ssh1_read_bignum(p, &key.exponent);
1446 p += ssh1_read_bignum(p, &key.modulus);
b8bb811a 1447 commentlen = GET_32BIT(p); p += 4;
1448 commentp = p; p += commentlen;
5c58ad2d 1449 send_packet(SSH1_CMSG_AUTH_RSA,
1450 PKT_BIGNUM, key.modulus, PKT_END);
1451 crWaitUntil(ispkt);
1452 if (pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
1453 logevent("Key refused");
1454 continue;
1455 }
1456 logevent("Received RSA challenge");
1457 ssh1_read_bignum(pktin.body, &challenge);
1458 {
1459 char *agentreq, *q, *ret;
1460 int len, retlen;
1461 len = 1 + 4; /* message type, bit count */
1462 len += ssh1_bignum_length(key.exponent);
1463 len += ssh1_bignum_length(key.modulus);
1464 len += ssh1_bignum_length(challenge);
1465 len += 16; /* session id */
1466 len += 4; /* response format */
dcbde236 1467 agentreq = smalloc(4 + len);
5c58ad2d 1468 PUT_32BIT(agentreq, len);
1469 q = agentreq + 4;
1470 *q++ = SSH_AGENTC_RSA_CHALLENGE;
1471 PUT_32BIT(q, ssh1_bignum_bitcount(key.modulus));
1472 q += 4;
1473 q += ssh1_write_bignum(q, key.exponent);
1474 q += ssh1_write_bignum(q, key.modulus);
1475 q += ssh1_write_bignum(q, challenge);
1476 memcpy(q, session_id, 16); q += 16;
1477 PUT_32BIT(q, 1); /* response format */
1478 agent_query(agentreq, len+4, &ret, &retlen);
dcbde236 1479 sfree(agentreq);
5c58ad2d 1480 if (ret) {
1481 if (ret[4] == SSH_AGENT_RSA_RESPONSE) {
1482 logevent("Sending Pageant's response");
1483 send_packet(SSH1_CMSG_AUTH_RSA_RESPONSE,
1484 PKT_DATA, ret+5, 16, PKT_END);
dcbde236 1485 sfree(ret);
5c58ad2d 1486 crWaitUntil(ispkt);
1487 if (pktin.type == SSH1_SMSG_SUCCESS) {
1488 logevent("Pageant's response accepted");
c4fa2fce 1489 if (flags & FLAG_VERBOSE) {
1490 c_write("Authenticated using RSA key \"",
1491 29);
1492 c_write(commentp, commentlen);
1493 c_write("\" from agent\r\n", 14);
1494 }
5c58ad2d 1495 authed = TRUE;
1496 } else
1497 logevent("Pageant's response not accepted");
1498 } else {
1499 logevent("Pageant failed to answer challenge");
dcbde236 1500 sfree(ret);
5c58ad2d 1501 }
1502 } else {
1503 logevent("No reply received from Pageant");
1504 }
1505 }
1506 freebn(key.exponent);
1507 freebn(key.modulus);
1508 freebn(challenge);
1509 if (authed)
1510 break;
1511 }
1512 }
1513 if (authed)
1514 break;
1515 }
7cca0d81 1516 if (*cfg.keyfile && !tried_publickey)
1517 pwpkt_type = SSH1_CMSG_AUTH_RSA;
fb09bf1c 1518
a52f067e 1519 if (pktin.type == SSH1_SMSG_FAILURE &&
1520 cfg.try_tis_auth &&
1521 (supported_auths_mask & (1<<SSH1_AUTH_TIS))) {
1522 pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
1523 logevent("Requested TIS authentication");
1524 send_packet(SSH1_CMSG_AUTH_TIS, PKT_END);
1525 crWaitUntil(ispkt);
1526 if (pktin.type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
1527 logevent("TIS authentication declined");
1528 if (flags & FLAG_INTERACTIVE)
1529 c_write("TIS authentication refused.\r\n", 29);
1530 } else {
1531 int challengelen = ((pktin.body[0] << 24) |
1532 (pktin.body[1] << 16) |
1533 (pktin.body[2] << 8) |
1534 (pktin.body[3]));
1535 logevent("Received TIS challenge");
1536 if (challengelen > sizeof(prompt)-1)
1537 challengelen = sizeof(prompt)-1; /* prevent overrun */
1538 memcpy(prompt, pktin.body+4, challengelen);
1539 prompt[challengelen] = '\0';
1540 }
1541 }
1542 if (pktin.type == SSH1_SMSG_FAILURE &&
1543 cfg.try_tis_auth &&
1544 (supported_auths_mask & (1<<SSH1_AUTH_CCARD))) {
1545 pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE;
1546 logevent("Requested CryptoCard authentication");
1547 send_packet(SSH1_CMSG_AUTH_CCARD, PKT_END);
1548 crWaitUntil(ispkt);
1549 if (pktin.type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
1550 logevent("CryptoCard authentication declined");
1551 c_write("CryptoCard authentication refused.\r\n", 29);
1552 } else {
1553 int challengelen = ((pktin.body[0] << 24) |
1554 (pktin.body[1] << 16) |
1555 (pktin.body[2] << 8) |
1556 (pktin.body[3]));
1557 logevent("Received CryptoCard challenge");
1558 if (challengelen > sizeof(prompt)-1)
1559 challengelen = sizeof(prompt)-1; /* prevent overrun */
1560 memcpy(prompt, pktin.body+4, challengelen);
1561 strncpy(prompt + challengelen, "\r\nResponse : ",
1562 sizeof(prompt)-challengelen);
1563 prompt[sizeof(prompt)-1] = '\0';
1564 }
1565 }
1566 if (pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
1567 sprintf(prompt, "%.90s@%.90s's password: ",
b585ec46 1568 username, savedhost);
a52f067e 1569 }
1570 if (pwpkt_type == SSH1_CMSG_AUTH_RSA) {
1571 char *comment = NULL;
1572 if (flags & FLAG_VERBOSE)
1573 c_write("Trying public key authentication.\r\n", 35);
1574 if (!rsakey_encrypted(cfg.keyfile, &comment)) {
1575 if (flags & FLAG_VERBOSE)
1576 c_write("No passphrase required.\r\n", 25);
1577 goto tryauth;
1578 }
1579 sprintf(prompt, "Passphrase for key \"%.100s\": ", comment);
dcbde236 1580 sfree(comment);
a52f067e 1581 }
1582
d8426c54 1583 if (ssh_get_password) {
85ee8208 1584 if (!ssh_get_password(prompt, password, sizeof(password))) {
1585 /*
1586 * get_password failed to get a password (for
1587 * example because one was supplied on the command
1588 * line which has already failed to work).
1589 * Terminate.
1590 */
1591 logevent("No more passwords to try");
1592 ssh_state = SSH_STATE_CLOSED;
1593 crReturn(1);
1594 }
fb09bf1c 1595 } else {
a52f067e 1596 c_write(prompt, strlen(prompt));
7cca0d81 1597 pos = 0;
67779be7 1598 ssh_send_ok = 1;
7cca0d81 1599 while (pos >= 0) {
1600 crWaitUntil(!ispkt);
1601 while (inlen--) switch (c = *in++) {
1602 case 10: case 13:
1603 password[pos] = 0;
1604 pos = -1;
1605 break;
1606 case 8: case 127:
1607 if (pos > 0)
1608 pos--;
1609 break;
1610 case 21: case 27:
1611 pos = 0;
1612 break;
1613 case 3: case 4:
1614 random_save_seed();
1615 exit(0);
1616 break;
1617 default:
1618 if (((c >= ' ' && c <= '~') ||
1619 ((unsigned char)c >= 160)) && pos < sizeof(password))
1620 password[pos++] = c;
1621 break;
1622 }
1623 }
1624 c_write("\r\n", 2);
a52f067e 1625 }
fb09bf1c 1626
7cca0d81 1627 tryauth:
1628 if (pwpkt_type == SSH1_CMSG_AUTH_RSA) {
1629 /*
1630 * Try public key authentication with the specified
1631 * key file.
1632 */
1633 static struct RSAKey pubkey;
1634 static Bignum challenge, response;
1635 static int i;
1636 static unsigned char buffer[32];
1637
1638 tried_publickey = 1;
6e522441 1639 i = loadrsakey(cfg.keyfile, &pubkey, NULL, password);
7cca0d81 1640 if (i == 0) {
1641 c_write("Couldn't load public key from ", 30);
1642 c_write(cfg.keyfile, strlen(cfg.keyfile));
1643 c_write(".\r\n", 3);
1644 continue; /* go and try password */
1645 }
1646 if (i == -1) {
1647 c_write("Wrong passphrase.\r\n", 19);
1648 tried_publickey = 0;
1649 continue; /* try again */
1650 }
1651
1652 /*
1653 * Send a public key attempt.
1654 */
1655 send_packet(SSH1_CMSG_AUTH_RSA,
1656 PKT_BIGNUM, pubkey.modulus, PKT_END);
1657
1658 crWaitUntil(ispkt);
1659 if (pktin.type == SSH1_SMSG_FAILURE) {
a52f067e 1660 c_write("Server refused our public key.\r\n", 32);
7cca0d81 1661 continue; /* go and try password */
1662 }
8d5de777 1663 if (pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
1664 bombout(("Bizarre response to offer of public key"));
1665 crReturn(0);
1666 }
7cca0d81 1667 ssh1_read_bignum(pktin.body, &challenge);
1668 response = rsadecrypt(challenge, &pubkey);
1669 freebn(pubkey.private_exponent); /* burn the evidence */
1670
1671 for (i = 0; i < 32; i += 2) {
1672 buffer[i] = response[16-i/2] >> 8;
1673 buffer[i+1] = response[16-i/2] & 0xFF;
1674 }
1675
1676 MD5Init(&md5c);
1677 MD5Update(&md5c, buffer, 32);
1678 MD5Update(&md5c, session_id, 16);
1679 MD5Final(buffer, &md5c);
1680
1681 send_packet(SSH1_CMSG_AUTH_RSA_RESPONSE,
1682 PKT_DATA, buffer, 16, PKT_END);
1683
1684 crWaitUntil(ispkt);
1685 if (pktin.type == SSH1_SMSG_FAILURE) {
4017be6d 1686 if (flags & FLAG_VERBOSE)
1687 c_write("Failed to authenticate with our public key.\r\n",
1688 45);
7cca0d81 1689 continue; /* go and try password */
1690 } else if (pktin.type != SSH1_SMSG_SUCCESS) {
8d5de777 1691 bombout(("Bizarre response to RSA authentication response"));
1692 crReturn(0);
7cca0d81 1693 }
1694
1695 break; /* we're through! */
1696 } else {
1697 send_packet(pwpkt_type, PKT_STR, password, PKT_END);
1698 }
c5e9c988 1699 logevent("Sent password");
374330e2 1700 memset(password, 0, strlen(password));
fb09bf1c 1701 crWaitUntil(ispkt);
e5574168 1702 if (pktin.type == SSH1_SMSG_FAILURE) {
4017be6d 1703 if (flags & FLAG_VERBOSE)
1704 c_write("Access denied\r\n", 15);
c5e9c988 1705 logevent("Authentication refused");
e5574168 1706 } else if (pktin.type == SSH1_MSG_DISCONNECT) {
fb09bf1c 1707 logevent("Received disconnect request");
85ee8208 1708 ssh_state = SSH_STATE_CLOSED;
1709 crReturn(1);
e5574168 1710 } else if (pktin.type != SSH1_SMSG_SUCCESS) {
8d5de777 1711 bombout(("Strange packet received, type %d", pktin.type));
1712 crReturn(0);
374330e2 1713 }
1714 }
1715
c5e9c988 1716 logevent("Authentication successful");
1717
fb09bf1c 1718 crFinish(1);
1719}
1720
e5574168 1721static void ssh1_protocol(unsigned char *in, int inlen, int ispkt) {
fb09bf1c 1722 crBegin;
1723
1724 random_init();
1725
e5574168 1726 while (!do_ssh1_login(in, inlen, ispkt)) {
fb09bf1c 1727 crReturnV;
85ee8208 1728 }
1729 if (ssh_state == SSH_STATE_CLOSED)
1730 crReturnV;
fb09bf1c 1731
979310f1 1732 if (cfg.agentfwd && agent_exists()) {
dacbd0e8 1733 logevent("Requesting agent forwarding");
1734 send_packet(SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END);
1735 do { crReturnV; } while (!ispkt);
1736 if (pktin.type != SSH1_SMSG_SUCCESS && pktin.type != SSH1_SMSG_FAILURE) {
8d5de777 1737 bombout(("Protocol confusion"));
1738 crReturnV;
dacbd0e8 1739 } else if (pktin.type == SSH1_SMSG_FAILURE) {
1740 logevent("Agent forwarding refused");
db7d555c 1741 } else {
dacbd0e8 1742 logevent("Agent forwarding enabled");
db7d555c 1743 ssh_agentfwd_enabled = TRUE;
1744 }
dacbd0e8 1745 }
1746
fef97f43 1747 if (!cfg.nopty) {
e5574168 1748 send_packet(SSH1_CMSG_REQUEST_PTY,
fb09bf1c 1749 PKT_STR, cfg.termtype,
1750 PKT_INT, rows, PKT_INT, cols,
1751 PKT_INT, 0, PKT_INT, 0,
1752 PKT_CHAR, 0,
1753 PKT_END);
fef97f43 1754 ssh_state = SSH_STATE_INTERMED;
1755 do { crReturnV; } while (!ispkt);
e5574168 1756 if (pktin.type != SSH1_SMSG_SUCCESS && pktin.type != SSH1_SMSG_FAILURE) {
8d5de777 1757 bombout(("Protocol confusion"));
1758 crReturnV;
e5574168 1759 } else if (pktin.type == SSH1_SMSG_FAILURE) {
fef97f43 1760 c_write("Server refused to allocate pty\r\n", 32);
1761 }
c5e9c988 1762 logevent("Allocated pty");
374330e2 1763 }
1764
4ba9b64b 1765 if (cfg.compression) {
1766 send_packet(SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END);
1767 do { crReturnV; } while (!ispkt);
1768 if (pktin.type != SSH1_SMSG_SUCCESS && pktin.type != SSH1_SMSG_FAILURE) {
1769 bombout(("Protocol confusion"));
1770 crReturnV;
1771 } else if (pktin.type == SSH1_SMSG_FAILURE) {
1772 c_write("Server refused to compress\r\n", 32);
1773 }
1774 logevent("Started compression");
1775 ssh1_compressing = TRUE;
1776 zlib_compress_init();
1777 zlib_decompress_init();
1778 }
1779
6abbf9e3 1780 if (*cfg.remote_cmd)
1781 send_packet(SSH1_CMSG_EXEC_CMD, PKT_STR, cfg.remote_cmd, PKT_END);
1782 else
1783 send_packet(SSH1_CMSG_EXEC_SHELL, PKT_END);
c5e9c988 1784 logevent("Started session");
374330e2 1785
1786 ssh_state = SSH_STATE_SESSION;
1787 if (size_needed)
1788 ssh_size();
3687d221 1789 if (eof_needed)
1790 ssh_special(TS_EOF);
374330e2 1791
8ccc75b0 1792 ssh_send_ok = 1;
dacbd0e8 1793 ssh_channels = newtree234(ssh_channelcmp);
6f34e365 1794 begin_session();
374330e2 1795 while (1) {
1796 crReturnV;
1797 if (ispkt) {
e5574168 1798 if (pktin.type == SSH1_SMSG_STDOUT_DATA ||
1799 pktin.type == SSH1_SMSG_STDERR_DATA) {
fb09bf1c 1800 long len = GET_32BIT(pktin.body);
fe50e814 1801 from_backend(pktin.type == SSH1_SMSG_STDERR_DATA,
1802 pktin.body+4, len);
e5574168 1803 } else if (pktin.type == SSH1_MSG_DISCONNECT) {
21248260 1804 ssh_state = SSH_STATE_CLOSED;
c5e9c988 1805 logevent("Received disconnect request");
3257deae 1806 crReturnV;
dacbd0e8 1807 } else if (pktin.type == SSH1_SMSG_AGENT_OPEN) {
1808 /* Remote side is trying to open a channel to talk to our
1809 * agent. Give them back a local channel number. */
db7d555c 1810 unsigned i;
dacbd0e8 1811 struct ssh_channel *c;
1812 enum234 e;
db7d555c 1813
1814 /* Refuse if agent forwarding is disabled. */
1815 if (!ssh_agentfwd_enabled) {
1816 send_packet(SSH1_MSG_CHANNEL_OPEN_FAILURE,
1817 PKT_INT, GET_32BIT(pktin.body),
1818 PKT_END);
1819 } else {
1820 i = 1;
1821 for (c = first234(ssh_channels, &e); c; c = next234(&e)) {
1822 if (c->localid > i)
1823 break; /* found a free number */
1824 i = c->localid + 1;
1825 }
dcbde236 1826 c = smalloc(sizeof(struct ssh_channel));
db7d555c 1827 c->remoteid = GET_32BIT(pktin.body);
1828 c->localid = i;
1829 c->closes = 0;
1830 c->type = SSH1_SMSG_AGENT_OPEN;/* identify channel type */
1831 c->u.a.lensofar = 0;
1832 add234(ssh_channels, c);
1833 send_packet(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
1834 PKT_INT, c->remoteid, PKT_INT, c->localid,
1835 PKT_END);
1836 }
1837 } else if (pktin.type == SSH1_MSG_CHANNEL_CLOSE ||
1838 pktin.type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION) {
dacbd0e8 1839 /* Remote side closes a channel. */
d211621f 1840 unsigned i = GET_32BIT(pktin.body);
dacbd0e8 1841 struct ssh_channel *c;
1842 c = find234(ssh_channels, &i, ssh_channelfind);
1843 if (c) {
1844 int closetype;
1845 closetype = (pktin.type == SSH1_MSG_CHANNEL_CLOSE ? 1 : 2);
1846 send_packet(pktin.type, PKT_INT, c->remoteid, PKT_END);
1847 c->closes |= closetype;
1848 if (c->closes == 3) {
1849 del234(ssh_channels, c);
dcbde236 1850 sfree(c);
dacbd0e8 1851 }
1852 }
1853 } else if (pktin.type == SSH1_MSG_CHANNEL_DATA) {
1854 /* Data sent down one of our channels. */
1855 int i = GET_32BIT(pktin.body);
1856 int len = GET_32BIT(pktin.body+4);
1857 unsigned char *p = pktin.body+8;
1858 struct ssh_channel *c;
1859 c = find234(ssh_channels, &i, ssh_channelfind);
1860 if (c) {
1861 switch(c->type) {
1862 case SSH1_SMSG_AGENT_OPEN:
1863 /* Data for an agent message. Buffer it. */
1864 while (len > 0) {
1865 if (c->u.a.lensofar < 4) {
1866 int l = min(4 - c->u.a.lensofar, len);
1867 memcpy(c->u.a.msglen + c->u.a.lensofar, p, l);
1868 p += l; len -= l; c->u.a.lensofar += l;
1869 }
1870 if (c->u.a.lensofar == 4) {
1871 c->u.a.totallen = 4 + GET_32BIT(c->u.a.msglen);
dcbde236 1872 c->u.a.message = smalloc(c->u.a.totallen);
dacbd0e8 1873 memcpy(c->u.a.message, c->u.a.msglen, 4);
1874 }
1875 if (c->u.a.lensofar >= 4 && len > 0) {
1876 int l = min(c->u.a.totallen - c->u.a.lensofar, len);
1877 memcpy(c->u.a.message + c->u.a.lensofar, p, l);
1878 p += l; len -= l; c->u.a.lensofar += l;
1879 }
1880 if (c->u.a.lensofar == c->u.a.totallen) {
1881 void *reply, *sentreply;
1882 int replylen;
1883 agent_query(c->u.a.message, c->u.a.totallen,
1884 &reply, &replylen);
1885 if (reply)
1886 sentreply = reply;
1887 else {
1888 /* Fake SSH_AGENT_FAILURE. */
1889 sentreply = "\0\0\0\1\5";
1890 replylen = 5;
1891 }
1892 send_packet(SSH1_MSG_CHANNEL_DATA,
1893 PKT_INT, c->remoteid,
1894 PKT_INT, replylen,
1895 PKT_DATA, sentreply, replylen,
1896 PKT_END);
1897 if (reply)
dcbde236 1898 sfree(reply);
1899 sfree(c->u.a.message);
dacbd0e8 1900 c->u.a.lensofar = 0;
1901 }
1902 }
1903 break;
1904 }
1905 }
e5574168 1906 } else if (pktin.type == SSH1_SMSG_SUCCESS) {
972a41c8 1907 /* may be from EXEC_SHELL on some servers */
e5574168 1908 } else if (pktin.type == SSH1_SMSG_FAILURE) {
972a41c8 1909 /* may be from EXEC_SHELL on some servers
374330e2 1910 * if no pty is available or in other odd cases. Ignore */
e5574168 1911 } else if (pktin.type == SSH1_SMSG_EXIT_STATUS) {
1912 send_packet(SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
374330e2 1913 } else {
8d5de777 1914 bombout(("Strange packet received: type %d", pktin.type));
1915 crReturnV;
374330e2 1916 }
1917 } else {
8df7a775 1918 while (inlen > 0) {
1919 int len = min(inlen, 512);
1920 send_packet(SSH1_CMSG_STDIN_DATA,
1921 PKT_INT, len, PKT_DATA, in, len, PKT_END);
1922 in += len;
1923 inlen -= len;
1924 }
374330e2 1925 }
1926 }
1927
1928 crFinishV;
1929}
1930
1931/*
e5574168 1932 * Utility routine for decoding comma-separated strings in KEXINIT.
1933 */
75cab814 1934static int in_commasep_string(char *needle, char *haystack, int haylen) {
e5574168 1935 int needlen = strlen(needle);
1936 while (1) {
1937 /*
1938 * Is it at the start of the string?
1939 */
1940 if (haylen >= needlen && /* haystack is long enough */
1941 !memcmp(needle, haystack, needlen) && /* initial match */
1942 (haylen == needlen || haystack[needlen] == ',')
1943 /* either , or EOS follows */
1944 )
1945 return 1;
1946 /*
1947 * If not, search for the next comma and resume after that.
1948 * If no comma found, terminate.
1949 */
1950 while (haylen > 0 && *haystack != ',')
1951 haylen--, haystack++;
1952 if (haylen == 0)
1953 return 0;
1954 haylen--, haystack++; /* skip over comma itself */
1955 }
1956}
1957
1958/*
d39f364a 1959 * SSH2 key creation method.
1960 */
75cab814 1961static void ssh2_mkkey(Bignum K, char *H, char chr, char *keyspace) {
d39f364a 1962 SHA_State s;
1963 /* First 20 bytes. */
1964 SHA_Init(&s);
1965 sha_mpint(&s, K);
1966 SHA_Bytes(&s, H, 20);
1967 SHA_Bytes(&s, &chr, 1);
1968 SHA_Bytes(&s, H, 20);
1969 SHA_Final(&s, keyspace);
1970 /* Next 20 bytes. */
1971 SHA_Init(&s);
1972 sha_mpint(&s, K);
1973 SHA_Bytes(&s, H, 20);
1974 SHA_Bytes(&s, keyspace, 20);
1975 SHA_Final(&s, keyspace+20);
1976}
1977
1978/*
7cca0d81 1979 * Handle the SSH2 transport layer.
e5574168 1980 */
7cca0d81 1981static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt)
e5574168 1982{
1983 static int i, len;
1984 static char *str;
1985 static Bignum e, f, K;
7591b9ff 1986 static const struct ssh_mac **maclist;
8b2715b2 1987 static int nmacs;
57476f6b 1988 static const struct ssh_cipher *cscipher_tobe = NULL;
1989 static const struct ssh_cipher *sccipher_tobe = NULL;
1990 static const struct ssh_mac *csmac_tobe = NULL;
1991 static const struct ssh_mac *scmac_tobe = NULL;
1992 static const struct ssh_compress *cscomp_tobe = NULL;
1993 static const struct ssh_compress *sccomp_tobe = NULL;
d5859615 1994 static char *hostkeydata, *sigdata, *keystr, *fingerprint;
e5574168 1995 static int hostkeylen, siglen;
e055a386 1996 static void *hkey; /* actual host key */
e5574168 1997 static unsigned char exchange_hash[20];
d39f364a 1998 static unsigned char keyspace[40];
57476f6b 1999 static const struct ssh_cipher *preferred_cipher;
4ba9b64b 2000 static const struct ssh_compress *preferred_comp;
0db56f73 2001 static int first_kex;
e5574168 2002
2003 crBegin;
7cca0d81 2004 random_init();
0db56f73 2005 first_kex = 1;
e5574168 2006
5e8358ad 2007 /*
4ba9b64b 2008 * Set up the preferred cipher and compression.
5e8358ad 2009 */
2010 if (cfg.cipher == CIPHER_BLOWFISH) {
57476f6b 2011 preferred_cipher = &ssh_blowfish_ssh2;
5e8358ad 2012 } else if (cfg.cipher == CIPHER_DES) {
2013 logevent("Single DES not supported in SSH2; using 3DES");
57476f6b 2014 preferred_cipher = &ssh_3des_ssh2;
5e8358ad 2015 } else if (cfg.cipher == CIPHER_3DES) {
57476f6b 2016 preferred_cipher = &ssh_3des_ssh2;
5e8358ad 2017 } else {
2018 /* Shouldn't happen, but we do want to initialise to _something_. */
57476f6b 2019 preferred_cipher = &ssh_3des_ssh2;
5e8358ad 2020 }
4ba9b64b 2021 if (cfg.compression)
2022 preferred_comp = &ssh_zlib;
2023 else
2024 preferred_comp = &ssh_comp_none;
5e8358ad 2025
7591b9ff 2026 /*
2027 * Be prepared to work around the buggy MAC problem.
2028 */
2029 if (cfg.buggymac)
8b2715b2 2030 maclist = buggymacs, nmacs = lenof(buggymacs);
7591b9ff 2031 else
8b2715b2 2032 maclist = macs, nmacs = lenof(macs);
7591b9ff 2033
7cca0d81 2034 begin_key_exchange:
e5574168 2035 /*
2036 * Construct and send our key exchange packet.
2037 */
2038 ssh2_pkt_init(SSH2_MSG_KEXINIT);
2039 for (i = 0; i < 16; i++)
2040 ssh2_pkt_addbyte((unsigned char)random_byte());
2041 /* List key exchange algorithms. */
2042 ssh2_pkt_addstring_start();
2043 for (i = 0; i < lenof(kex_algs); i++) {
2044 ssh2_pkt_addstring_str(kex_algs[i]->name);
2045 if (i < lenof(kex_algs)-1)
2046 ssh2_pkt_addstring_str(",");
2047 }
2048 /* List server host key algorithms. */
2049 ssh2_pkt_addstring_start();
2050 for (i = 0; i < lenof(hostkey_algs); i++) {
2051 ssh2_pkt_addstring_str(hostkey_algs[i]->name);
2052 if (i < lenof(hostkey_algs)-1)
2053 ssh2_pkt_addstring_str(",");
2054 }
2055 /* List client->server encryption algorithms. */
2056 ssh2_pkt_addstring_start();
729e54b4 2057 for (i = 0; i < lenof(ciphers)+1; i++) {
2058 const struct ssh_cipher *c = i==0 ? preferred_cipher : ciphers[i-1];
57476f6b 2059 ssh2_pkt_addstring_str(c->name);
729e54b4 2060 if (i < lenof(ciphers))
e5574168 2061 ssh2_pkt_addstring_str(",");
2062 }
2063 /* List server->client encryption algorithms. */
2064 ssh2_pkt_addstring_start();
729e54b4 2065 for (i = 0; i < lenof(ciphers)+1; i++) {
2066 const struct ssh_cipher *c = i==0 ? preferred_cipher : ciphers[i-1];
57476f6b 2067 ssh2_pkt_addstring_str(c->name);
729e54b4 2068 if (i < lenof(ciphers))
e5574168 2069 ssh2_pkt_addstring_str(",");
2070 }
2071 /* List client->server 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 server->client MAC algorithms. */
2079 ssh2_pkt_addstring_start();
8b2715b2 2080 for (i = 0; i < nmacs; i++) {
7591b9ff 2081 ssh2_pkt_addstring_str(maclist[i]->name);
8b2715b2 2082 if (i < nmacs-1)
e5574168 2083 ssh2_pkt_addstring_str(",");
2084 }
2085 /* List client->server compression algorithms. */
2086 ssh2_pkt_addstring_start();
4ba9b64b 2087 for (i = 0; i < lenof(compressions)+1; i++) {
2088 const struct ssh_compress *c = i==0 ? preferred_comp : compressions[i-1];
2089 ssh2_pkt_addstring_str(c->name);
2090 if (i < lenof(compressions))
e5574168 2091 ssh2_pkt_addstring_str(",");
2092 }
2093 /* List server->client compression algorithms. */
2094 ssh2_pkt_addstring_start();
4ba9b64b 2095 for (i = 0; i < lenof(compressions)+1; i++) {
2096 const struct ssh_compress *c = i==0 ? preferred_comp : compressions[i-1];
2097 ssh2_pkt_addstring_str(c->name);
2098 if (i < lenof(compressions))
e5574168 2099 ssh2_pkt_addstring_str(",");
2100 }
2101 /* List client->server languages. Empty list. */
2102 ssh2_pkt_addstring_start();
2103 /* List server->client languages. Empty list. */
2104 ssh2_pkt_addstring_start();
2105 /* First KEX packet does _not_ follow, because we're not that brave. */
2106 ssh2_pkt_addbool(FALSE);
2107 /* Reserved. */
2108 ssh2_pkt_adduint32(0);
0db56f73 2109
2110 exhash = exhashbase;
e5574168 2111 sha_string(&exhash, pktout.data+5, pktout.length-5);
0db56f73 2112
e5574168 2113 ssh2_pkt_send();
2114
2115 if (!ispkt) crWaitUntil(ispkt);
2116 sha_string(&exhash, pktin.data+5, pktin.length-5);
2117
2118 /*
2119 * Now examine the other side's KEXINIT to see what we're up
2120 * to.
2121 */
7cca0d81 2122 if (pktin.type != SSH2_MSG_KEXINIT) {
8d5de777 2123 bombout(("expected key exchange packet from server"));
2124 crReturn(0);
7cca0d81 2125 }
e5574168 2126 kex = NULL; hostkey = NULL; cscipher_tobe = NULL; sccipher_tobe = NULL;
2127 csmac_tobe = NULL; scmac_tobe = NULL; cscomp_tobe = NULL; sccomp_tobe = NULL;
2128 pktin.savedpos += 16; /* skip garbage cookie */
2129 ssh2_pkt_getstring(&str, &len); /* key exchange algorithms */
2130 for (i = 0; i < lenof(kex_algs); i++) {
2131 if (in_commasep_string(kex_algs[i]->name, str, len)) {
2132 kex = kex_algs[i];
2133 break;
2134 }
2135 }
2136 ssh2_pkt_getstring(&str, &len); /* host key algorithms */
2137 for (i = 0; i < lenof(hostkey_algs); i++) {
2138 if (in_commasep_string(hostkey_algs[i]->name, str, len)) {
2139 hostkey = hostkey_algs[i];
2140 break;
2141 }
2142 }
2143 ssh2_pkt_getstring(&str, &len); /* client->server cipher */
729e54b4 2144 for (i = 0; i < lenof(ciphers)+1; i++) {
2145 const struct ssh_cipher *c = i==0 ? preferred_cipher : ciphers[i-1];
57476f6b 2146 if (in_commasep_string(c->name, str, len)) {
729e54b4 2147 cscipher_tobe = c;
e5574168 2148 break;
2149 }
2150 }
2151 ssh2_pkt_getstring(&str, &len); /* server->client cipher */
729e54b4 2152 for (i = 0; i < lenof(ciphers)+1; i++) {
2153 const struct ssh_cipher *c = i==0 ? preferred_cipher : ciphers[i-1];
57476f6b 2154 if (in_commasep_string(c->name, str, len)) {
729e54b4 2155 sccipher_tobe = c;
e5574168 2156 break;
2157 }
2158 }
2159 ssh2_pkt_getstring(&str, &len); /* client->server mac */
8b2715b2 2160 for (i = 0; i < nmacs; i++) {
7591b9ff 2161 if (in_commasep_string(maclist[i]->name, str, len)) {
2162 csmac_tobe = maclist[i];
e5574168 2163 break;
2164 }
2165 }
2166 ssh2_pkt_getstring(&str, &len); /* server->client mac */
8b2715b2 2167 for (i = 0; i < nmacs; i++) {
7591b9ff 2168 if (in_commasep_string(maclist[i]->name, str, len)) {
2169 scmac_tobe = maclist[i];
e5574168 2170 break;
2171 }
2172 }
2173 ssh2_pkt_getstring(&str, &len); /* client->server compression */
4ba9b64b 2174 for (i = 0; i < lenof(compressions)+1; i++) {
2175 const struct ssh_compress *c = i==0 ? preferred_comp : compressions[i-1];
2176 if (in_commasep_string(c->name, str, len)) {
2177 cscomp_tobe = c;
e5574168 2178 break;
2179 }
2180 }
2181 ssh2_pkt_getstring(&str, &len); /* server->client compression */
4ba9b64b 2182 for (i = 0; i < lenof(compressions)+1; i++) {
2183 const struct ssh_compress *c = i==0 ? preferred_comp : compressions[i-1];
2184 if (in_commasep_string(c->name, str, len)) {
2185 sccomp_tobe = c;
e5574168 2186 break;
2187 }
2188 }
e5574168 2189
2190 /*
2191 * Currently we only support Diffie-Hellman and DSS, so let's
2192 * bomb out if those aren't selected.
2193 */
8d5de777 2194 if (kex != &ssh_diffiehellman || hostkey != &ssh_dss) {
2195 bombout(("internal fault: chaos in SSH 2 transport layer"));
2196 crReturn(0);
2197 }
e5574168 2198
2199 /*
2200 * Now we begin the fun. Generate and send e for Diffie-Hellman.
2201 */
2202 e = dh_create_e();
e5574168 2203 ssh2_pkt_init(SSH2_MSG_KEXDH_INIT);
2204 ssh2_pkt_addmp(e);
2205 ssh2_pkt_send();
2206
2207 crWaitUntil(ispkt);
7cca0d81 2208 if (pktin.type != SSH2_MSG_KEXDH_REPLY) {
8d5de777 2209 bombout(("expected key exchange packet from server"));
2210 crReturn(0);
7cca0d81 2211 }
e5574168 2212 ssh2_pkt_getstring(&hostkeydata, &hostkeylen);
2213 f = ssh2_pkt_getmp();
e5574168 2214 ssh2_pkt_getstring(&sigdata, &siglen);
2215
2216 K = dh_find_K(f);
e5574168 2217
2218 sha_string(&exhash, hostkeydata, hostkeylen);
2219 sha_mpint(&exhash, e);
2220 sha_mpint(&exhash, f);
2221 sha_mpint(&exhash, K);
2222 SHA_Final(&exhash, exchange_hash);
2223
7cca0d81 2224#if 0
e5574168 2225 debug(("Exchange hash is:\r\n"));
2226 for (i = 0; i < 20; i++)
2227 debug((" %02x", exchange_hash[i]));
2228 debug(("\r\n"));
7cca0d81 2229#endif
2230
e055a386 2231 hkey = hostkey->newkey(hostkeydata, hostkeylen);
2232 if (!hostkey->verifysig(hkey, sigdata, siglen, exchange_hash, 20)) {
8d5de777 2233 bombout(("Server failed host key check"));
2234 crReturn(0);
2235 }
e5574168 2236
2237 /*
7cca0d81 2238 * Expect SSH2_MSG_NEWKEYS from server.
d39f364a 2239 */
7cca0d81 2240 crWaitUntil(ispkt);
8d5de777 2241 if (pktin.type != SSH2_MSG_NEWKEYS) {
2242 bombout(("expected new-keys packet from server"));
2243 crReturn(0);
2244 }
d39f364a 2245
2246 /*
7cca0d81 2247 * Authenticate remote host: verify host key. (We've already
2248 * checked the signature of the exchange hash.)
e5574168 2249 */
e055a386 2250 keystr = hostkey->fmtkey(hkey);
2251 fingerprint = hostkey->fingerprint(hkey);
d4857987 2252 verify_ssh_host_key(savedhost, savedport, hostkey->keytype,
2253 keystr, fingerprint);
d5859615 2254 logevent("Host key fingerprint is:");
2255 logevent(fingerprint);
dcbde236 2256 sfree(fingerprint);
2257 sfree(keystr);
e055a386 2258 hostkey->freekey(hkey);
d39f364a 2259
2260 /*
7cca0d81 2261 * Send SSH2_MSG_NEWKEYS.
d39f364a 2262 */
2263 ssh2_pkt_init(SSH2_MSG_NEWKEYS);
2264 ssh2_pkt_send();
d39f364a 2265
2266 /*
2267 * Create and initialise session keys.
2268 */
2269 cscipher = cscipher_tobe;
2270 sccipher = sccipher_tobe;
2271 csmac = csmac_tobe;
2272 scmac = scmac_tobe;
2273 cscomp = cscomp_tobe;
2274 sccomp = sccomp_tobe;
4ba9b64b 2275 cscomp->compress_init();
2276 sccomp->decompress_init();
d39f364a 2277 /*
2278 * Set IVs after keys.
2279 */
2280 ssh2_mkkey(K, exchange_hash, 'C', keyspace); cscipher->setcskey(keyspace);
2281 ssh2_mkkey(K, exchange_hash, 'D', keyspace); cscipher->setsckey(keyspace);
2282 ssh2_mkkey(K, exchange_hash, 'A', keyspace); cscipher->setcsiv(keyspace);
2283 ssh2_mkkey(K, exchange_hash, 'B', keyspace); sccipher->setsciv(keyspace);
2284 ssh2_mkkey(K, exchange_hash, 'E', keyspace); csmac->setcskey(keyspace);
2285 ssh2_mkkey(K, exchange_hash, 'F', keyspace); scmac->setsckey(keyspace);
2286
033b4cef 2287 /*
0db56f73 2288 * If this is the first key exchange phase, we must pass the
2289 * SSH2_MSG_NEWKEYS packet to the next layer, not because it
2290 * wants to see it but because it will need time to initialise
2291 * itself before it sees an actual packet. In subsequent key
2292 * exchange phases, we don't pass SSH2_MSG_NEWKEYS on, because
2293 * it would only confuse the layer above.
2294 */
2295 if (!first_kex) {
2296 crReturn(0);
2297 }
2298 first_kex = 0;
2299
2300 /*
7cca0d81 2301 * Now we're encrypting. Begin returning 1 to the protocol main
2302 * function so that other things can run on top of the
2303 * transport. If we ever see a KEXINIT, we must go back to the
2304 * start.
033b4cef 2305 */
7cca0d81 2306 do {
2307 crReturn(1);
2308 } while (!(ispkt && pktin.type == SSH2_MSG_KEXINIT));
2309 goto begin_key_exchange;
e5574168 2310
2311 crFinish(1);
2312}
2313
7cca0d81 2314/*
2315 * Handle the SSH2 userauth and connection layers.
2316 */
2317static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt)
2318{
7cca0d81 2319 static unsigned long remote_winsize;
2320 static unsigned long remote_maxpkt;
2321
e5574168 2322 crBegin;
2323
7cca0d81 2324 /*
2325 * Request userauth protocol, and await a response to it.
2326 */
2327 ssh2_pkt_init(SSH2_MSG_SERVICE_REQUEST);
2328 ssh2_pkt_addstring("ssh-userauth");
2329 ssh2_pkt_send();
2330 crWaitUntilV(ispkt);
8d5de777 2331 if (pktin.type != SSH2_MSG_SERVICE_ACCEPT) {
2332 bombout(("Server refused user authentication protocol"));
2333 crReturnV;
2334 }
7cca0d81 2335
2336 /*
2337 * FIXME: currently we support only password authentication.
2338 * (This places us technically in violation of the SSH2 spec.
2339 * We must fix this.)
2340 */
2341 while (1) {
2342 /*
2343 * Get a username and a password.
2344 */
2345 static char username[100];
2346 static char password[100];
2347 static int pos = 0;
2348 static char c;
e5574168 2349
67779be7 2350 if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
7cca0d81 2351 c_write("login as: ", 10);
67779be7 2352 ssh_send_ok = 1;
7cca0d81 2353 while (pos >= 0) {
2354 crWaitUntilV(!ispkt);
2355 while (inlen--) switch (c = *in++) {
2356 case 10: case 13:
2357 username[pos] = 0;
2358 pos = -1;
2359 break;
2360 case 8: case 127:
2361 if (pos > 0) {
2362 c_write("\b \b", 3);
2363 pos--;
2364 }
2365 break;
2366 case 21: case 27:
2367 while (pos > 0) {
2368 c_write("\b \b", 3);
2369 pos--;
2370 }
2371 break;
2372 case 3: case 4:
2373 random_save_seed();
2374 exit(0);
2375 break;
2376 default:
2377 if (((c >= ' ' && c <= '~') ||
2378 ((unsigned char)c >= 160)) && pos < 40) {
2379 username[pos++] = c;
2380 c_write(&c, 1);
2381 }
2382 break;
2383 }
2384 }
2385 c_write("\r\n", 2);
2386 username[strcspn(username, "\n\r")] = '\0';
2387 } else {
2388 char stuff[200];
2389 strncpy(username, cfg.username, 99);
2390 username[99] = '\0';
67779be7 2391 if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
7cca0d81 2392 sprintf(stuff, "Using username \"%s\".\r\n", username);
2393 c_write(stuff, strlen(stuff));
2394 }
2395 }
2396
d8426c54 2397 if (ssh_get_password) {
7cca0d81 2398 char prompt[200];
b585ec46 2399 sprintf(prompt, "%.90s@%.90s's password: ", username, savedhost);
7cca0d81 2400 if (!ssh_get_password(prompt, password, sizeof(password))) {
2401 /*
2402 * get_password failed to get a password (for
2403 * example because one was supplied on the command
2404 * line which has already failed to work).
2405 * Terminate.
2406 */
2407 logevent("No more passwords to try");
2408 ssh_state = SSH_STATE_CLOSED;
2409 crReturnV;
2410 }
2411 } else {
2412 c_write("password: ", 10);
67779be7 2413 ssh_send_ok = 1;
7cca0d81 2414
2415 pos = 0;
2416 while (pos >= 0) {
2417 crWaitUntilV(!ispkt);
2418 while (inlen--) switch (c = *in++) {
2419 case 10: case 13:
2420 password[pos] = 0;
2421 pos = -1;
2422 break;
2423 case 8: case 127:
2424 if (pos > 0)
2425 pos--;
2426 break;
2427 case 21: case 27:
2428 pos = 0;
2429 break;
2430 case 3: case 4:
2431 random_save_seed();
2432 exit(0);
2433 break;
2434 default:
2435 if (((c >= ' ' && c <= '~') ||
2436 ((unsigned char)c >= 160)) && pos < 40)
2437 password[pos++] = c;
2438 break;
2439 }
2440 }
2441 c_write("\r\n", 2);
2442 }
2443
2444 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
2445 ssh2_pkt_addstring(username);
2446 ssh2_pkt_addstring("ssh-connection"); /* service requested */
2447 ssh2_pkt_addstring("password");
2448 ssh2_pkt_addbool(FALSE);
2449 ssh2_pkt_addstring(password);
2450 ssh2_pkt_send();
2451
2452 crWaitUntilV(ispkt);
2453 if (pktin.type != SSH2_MSG_USERAUTH_SUCCESS) {
2454 c_write("Access denied\r\n", 15);
2455 logevent("Authentication refused");
2456 } else
2457 break;
2458 }
2459
2460 /*
2461 * Now we're authenticated for the connection protocol. The
2462 * connection protocol will automatically have started at this
2463 * point; there's no need to send SERVICE_REQUEST.
2464 */
2465
2466 /*
2467 * So now create a channel with a session in it.
2468 */
dcbde236 2469 mainchan = smalloc(sizeof(struct ssh_channel));
d211621f 2470 mainchan->localid = 100; /* as good as any */
7cca0d81 2471 ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN);
2472 ssh2_pkt_addstring("session");
d211621f 2473 ssh2_pkt_adduint32(mainchan->localid);
cf6e59d6 2474 ssh2_pkt_adduint32(0x8000UL); /* our window size */
d211621f 2475 ssh2_pkt_adduint32(0x4000UL); /* our max pkt size */
7cca0d81 2476 ssh2_pkt_send();
2477 crWaitUntilV(ispkt);
2478 if (pktin.type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
8d5de777 2479 bombout(("Server refused to open a session"));
2480 crReturnV;
7cca0d81 2481 /* FIXME: error data comes back in FAILURE packet */
2482 }
d211621f 2483 if (ssh2_pkt_getuint32() != mainchan->localid) {
8d5de777 2484 bombout(("Server's channel confirmation cited wrong channel"));
2485 crReturnV;
7cca0d81 2486 }
d211621f 2487 mainchan->remoteid = ssh2_pkt_getuint32();
2488 mainchan->u.v2.remwindow = ssh2_pkt_getuint32();
2489 mainchan->u.v2.remmaxpkt = ssh2_pkt_getuint32();
2490 mainchan->u.v2.outbuffer = NULL;
2491 mainchan->u.v2.outbuflen = mainchan->u.v2.outbufsize = 0;
7cca0d81 2492 logevent("Opened channel for session");
2493
2494 /*
2495 * Now allocate a pty for the session.
2496 */
67779be7 2497 if (!cfg.nopty) {
2498 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
2499 ssh2_pkt_adduint32(mainchan->remoteid); /* recipient channel */
2500 ssh2_pkt_addstring("pty-req");
2501 ssh2_pkt_addbool(1); /* want reply */
2502 ssh2_pkt_addstring(cfg.termtype);
2503 ssh2_pkt_adduint32(cols);
2504 ssh2_pkt_adduint32(rows);
2505 ssh2_pkt_adduint32(0); /* pixel width */
2506 ssh2_pkt_adduint32(0); /* pixel height */
2507 ssh2_pkt_addstring_start();
2508 ssh2_pkt_addstring_data("\0", 1);/* TTY_OP_END, no special options */
2509 ssh2_pkt_send();
6e48c3fe 2510 ssh_state = SSH_STATE_INTERMED;
7cca0d81 2511
67779be7 2512 do {
2513 crWaitUntilV(ispkt);
2514 if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
2515 /* FIXME: be able to handle other channels here */
2516 if (ssh2_pkt_getuint32() != mainchan->localid)
2517 continue; /* wrong channel */
2518 mainchan->u.v2.remwindow += ssh2_pkt_getuint32();
2519 }
2520 } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
7cca0d81 2521
67779be7 2522 if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
2523 if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
8d5de777 2524 bombout(("Server got confused by pty request"));
2525 crReturnV;
67779be7 2526 }
2527 c_write("Server refused to allocate pty\r\n", 32);
2528 } else {
2529 logevent("Allocated pty");
7cca0d81 2530 }
7cca0d81 2531 }
2532
2533 /*
67779be7 2534 * Start a shell or a remote command.
7cca0d81 2535 */
2536 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
d211621f 2537 ssh2_pkt_adduint32(mainchan->remoteid); /* recipient channel */
67779be7 2538 if (*cfg.remote_cmd) {
2539 ssh2_pkt_addstring("exec");
2540 ssh2_pkt_addbool(1); /* want reply */
2541 ssh2_pkt_addstring(cfg.remote_cmd);
2542 } else {
2543 ssh2_pkt_addstring("shell");
2544 ssh2_pkt_addbool(1); /* want reply */
2545 }
7cca0d81 2546 ssh2_pkt_send();
d211621f 2547 do {
7cca0d81 2548 crWaitUntilV(ispkt);
d211621f 2549 if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
2550 /* FIXME: be able to handle other channels here */
2551 if (ssh2_pkt_getuint32() != mainchan->localid)
2552 continue; /* wrong channel */
2553 mainchan->u.v2.remwindow += ssh2_pkt_getuint32();
2554 }
7cca0d81 2555 } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
2556 if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
2557 if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
8d5de777 2558 bombout(("Server got confused by shell/command request"));
2559 crReturnV;
7cca0d81 2560 }
8d5de777 2561 bombout(("Server refused to start a shell/command"));
2562 crReturnV;
7cca0d81 2563 } else {
8d5de777 2564 logevent("Started a shell/command");
7cca0d81 2565 }
2566
6e48c3fe 2567 ssh_state = SSH_STATE_SESSION;
2568 if (size_needed)
2569 ssh_size();
3687d221 2570 if (eof_needed)
2571 ssh_special(TS_EOF);
6e48c3fe 2572
7cca0d81 2573 /*
2574 * Transfer data!
2575 */
8ccc75b0 2576 ssh_send_ok = 1;
6f34e365 2577 begin_session();
7cca0d81 2578 while (1) {
d211621f 2579 static int try_send;
e5574168 2580 crReturnV;
d211621f 2581 try_send = FALSE;
7cca0d81 2582 if (ispkt) {
2583 if (pktin.type == SSH2_MSG_CHANNEL_DATA ||
2584 pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA) {
2585 char *data;
2586 int length;
d211621f 2587 /* FIXME: be able to handle other channels here */
2588 if (ssh2_pkt_getuint32() != mainchan->localid)
7cca0d81 2589 continue; /* wrong channel */
2590 if (pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
2591 ssh2_pkt_getuint32() != SSH2_EXTENDED_DATA_STDERR)
2592 continue; /* extended but not stderr */
2593 ssh2_pkt_getstring(&data, &length);
d211621f 2594 if (data) {
fe50e814 2595 from_backend(pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA,
2596 data, length);
d211621f 2597 /*
2598 * Enlarge the window again at the remote side,
2599 * just in case it ever runs down and they fail
2600 * to send us any more data.
2601 */
2602 ssh2_pkt_init(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
2603 ssh2_pkt_adduint32(mainchan->remoteid);
2604 ssh2_pkt_adduint32(length);
2605 ssh2_pkt_send();
2606 }
7cca0d81 2607 } else if (pktin.type == SSH2_MSG_DISCONNECT) {
2608 ssh_state = SSH_STATE_CLOSED;
d211621f 2609 logevent("Received disconnect message");
3257deae 2610 crReturnV;
7cca0d81 2611 } else if (pktin.type == SSH2_MSG_CHANNEL_REQUEST) {
2612 continue; /* exit status et al; ignore (FIXME?) */
d211621f 2613 } else if (pktin.type == SSH2_MSG_CHANNEL_EOF) {
2614 continue; /* remote sends EOF; ignore */
2615 } else if (pktin.type == SSH2_MSG_CHANNEL_CLOSE) {
2616 /* FIXME: be able to handle other channels here */
2617 if (ssh2_pkt_getuint32() != mainchan->localid)
2618 continue; /* wrong channel */
2619 ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE);
2620 ssh2_pkt_adduint32(mainchan->remoteid);
2621 ssh2_pkt_send();
2622 /* FIXME: mark the channel as closed */
2623 if (1 /* FIXME: "all channels are closed" */) {
2624 logevent("All channels closed. Disconnecting");
2625 ssh2_pkt_init(SSH2_MSG_DISCONNECT);
9005f3ba 2626 ssh2_pkt_adduint32(SSH2_DISCONNECT_BY_APPLICATION);
2627 ssh2_pkt_addstring("All open channels closed");
2628 ssh2_pkt_addstring("en"); /* language tag */
d211621f 2629 ssh2_pkt_send();
cf6e59d6 2630 ssh_state = SSH_STATE_CLOSED;
3257deae 2631 crReturnV;
d211621f 2632 }
2633 continue; /* remote sends close; ignore (FIXME) */
7cca0d81 2634 } else if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
d211621f 2635 /* FIXME: be able to handle other channels here */
2636 if (ssh2_pkt_getuint32() != mainchan->localid)
2637 continue; /* wrong channel */
2638 mainchan->u.v2.remwindow += ssh2_pkt_getuint32();
2639 try_send = TRUE;
7cca0d81 2640 } else {
8d5de777 2641 bombout(("Strange packet received: type %d", pktin.type));
2642 crReturnV;
7cca0d81 2643 }
2644 } else {
d211621f 2645 /*
2646 * We have spare data. Add it to the channel buffer.
2647 */
2648 if (mainchan->u.v2.outbufsize <
2649 mainchan->u.v2.outbuflen + inlen) {
2650 mainchan->u.v2.outbufsize =
2651 mainchan->u.v2.outbuflen + inlen + 1024;
2652 mainchan->u.v2.outbuffer = srealloc(mainchan->u.v2.outbuffer,
2653 mainchan->u.v2.outbufsize);
2654 }
2655 memcpy(mainchan->u.v2.outbuffer + mainchan->u.v2.outbuflen,
2656 in, inlen);
2657 mainchan->u.v2.outbuflen += inlen;
2658 try_send = TRUE;
7cca0d81 2659 }
d211621f 2660 if (try_send) {
2661 /*
2662 * Try to send data on the channel if we can. (FIXME:
2663 * on _all_ channels.)
2664 */
2665 while (mainchan->u.v2.remwindow > 0 &&
2666 mainchan->u.v2.outbuflen > 0) {
2667 unsigned len = mainchan->u.v2.remwindow;
2668 if (len > mainchan->u.v2.outbuflen)
2669 len = mainchan->u.v2.outbuflen;
2670 if (len > mainchan->u.v2.remmaxpkt)
2671 len = mainchan->u.v2.remmaxpkt;
2672 ssh2_pkt_init(SSH2_MSG_CHANNEL_DATA);
2673 ssh2_pkt_adduint32(mainchan->remoteid);
2674 ssh2_pkt_addstring_start();
2675 ssh2_pkt_addstring_data(mainchan->u.v2.outbuffer, len);
2676 ssh2_pkt_send();
2677 mainchan->u.v2.outbuflen -= len;
2678 memmove(mainchan->u.v2.outbuffer, mainchan->u.v2.outbuffer+len,
2679 mainchan->u.v2.outbuflen);
2680 mainchan->u.v2.remwindow -= len;
2681 }
2682 }
e5574168 2683 }
2684
2685 crFinishV;
2686}
2687
2688/*
7cca0d81 2689 * Handle the top-level SSH2 protocol.
2690 */
2691static void ssh2_protocol(unsigned char *in, int inlen, int ispkt)
2692{
2693 if (do_ssh2_transport(in, inlen, ispkt) == 0)
2694 return;
2695 do_ssh2_authconn(in, inlen, ispkt);
2696}
2697
2698/*
8df7a775 2699 * Called to set up the connection.
374330e2 2700 *
2701 * Returns an error message, or NULL on success.
374330e2 2702 */
8df7a775 2703static char *ssh_init (char *host, int port, char **realhost) {
fb09bf1c 2704 char *p;
8f203108 2705
2706#ifdef MSCRYPTOAPI
2707 if(crypto_startup() == 0)
2708 return "Microsoft high encryption pack not installed!";
2709#endif
374330e2 2710
8df7a775 2711 ssh_send_ok = 0;
2712
fb09bf1c 2713 p = connect_to_host(host, port, realhost);
2714 if (p != NULL)
2715 return p;
374330e2 2716
374330e2 2717 return NULL;
2718}
2719
2720/*
374330e2 2721 * Called to send data down the Telnet connection.
2722 */
2723static void ssh_send (char *buf, int len) {
f78051a1 2724 if (s == NULL || ssh_protocol == NULL)
374330e2 2725 return;
2726
2727 ssh_protocol(buf, len, 0);
2728}
2729
2730/*
6e48c3fe 2731 * Called to set the size of the window from SSH's POV.
374330e2 2732 */
2733static void ssh_size(void) {
2734 switch (ssh_state) {
2735 case SSH_STATE_BEFORE_SIZE:
3687d221 2736 case SSH_STATE_PREPACKET:
21248260 2737 case SSH_STATE_CLOSED:
374330e2 2738 break; /* do nothing */
2739 case SSH_STATE_INTERMED:
2740 size_needed = TRUE; /* buffer for later */
2741 break;
2742 case SSH_STATE_SESSION:
fef97f43 2743 if (!cfg.nopty) {
6e48c3fe 2744 if (ssh_version == 1) {
2745 send_packet(SSH1_CMSG_WINDOW_SIZE,
2746 PKT_INT, rows, PKT_INT, cols,
2747 PKT_INT, 0, PKT_INT, 0, PKT_END);
2748 } else {
2749 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
2750 ssh2_pkt_adduint32(mainchan->remoteid);
2751 ssh2_pkt_addstring("window-change");
2752 ssh2_pkt_addbool(0);
2753 ssh2_pkt_adduint32(cols);
2754 ssh2_pkt_adduint32(rows);
2755 ssh2_pkt_adduint32(0);
2756 ssh2_pkt_adduint32(0);
2757 ssh2_pkt_send();
2758 }
fef97f43 2759 }
3687d221 2760 break;
374330e2 2761 }
2762}
2763
2764/*
6abbf9e3 2765 * Send Telnet special codes. TS_EOF is useful for `plink', so you
2766 * can send an EOF and collect resulting output (e.g. `plink
2767 * hostname sort').
374330e2 2768 */
2769static void ssh_special (Telnet_Special code) {
6abbf9e3 2770 if (code == TS_EOF) {
3687d221 2771 if (ssh_state != SSH_STATE_SESSION) {
2772 /*
2773 * Buffer the EOF in case we are pre-SESSION, so we can
2774 * send it as soon as we reach SESSION.
2775 */
2776 if (code == TS_EOF)
2777 eof_needed = TRUE;
2778 return;
2779 }
67779be7 2780 if (ssh_version == 1) {
6abbf9e3 2781 send_packet(SSH1_CMSG_EOF, PKT_END);
2782 } else {
2783 ssh2_pkt_init(SSH2_MSG_CHANNEL_EOF);
d211621f 2784 ssh2_pkt_adduint32(mainchan->remoteid);
6abbf9e3 2785 ssh2_pkt_send();
2786 }
67779be7 2787 logevent("Sent EOF message");
ec55b220 2788 } else if (code == TS_PING) {
3687d221 2789 if (ssh_state == SSH_STATE_CLOSED || ssh_state == SSH_STATE_PREPACKET)
2790 return;
ec55b220 2791 if (ssh_version == 1) {
2792 send_packet(SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
2793 } else {
2794 ssh2_pkt_init(SSH2_MSG_IGNORE);
2795 ssh2_pkt_addstring_start();
2796 ssh2_pkt_send();
2797 }
6abbf9e3 2798 } else {
2799 /* do nothing */
2800 }
374330e2 2801}
2802
8df7a775 2803static Socket ssh_socket(void) { return s; }
8ccc75b0 2804
2805static int ssh_sendok(void) { return ssh_send_ok; }
fb09bf1c 2806
374330e2 2807Backend ssh_backend = {
2808 ssh_init,
374330e2 2809 ssh_send,
2810 ssh_size,
4017be6d 2811 ssh_special,
8ccc75b0 2812 ssh_socket,
97db3be4 2813 ssh_sendok,
2814 22
374330e2 2815};
Local modifications for Simon Tatham's `PuTTY' SSH client and terminal emulator