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Using plink with CVS - need to make sure the saved session uses SSH
[u/mdw/putty] / ssh.c
1 #include <windows.h>
2 #include <stdio.h>
3 #include <stdlib.h>
4 #include <stdarg.h>
5 #include <assert.h>
6
7 #include "putty.h"
8 #include "tree234.h"
9 #include "ssh.h"
10
11 #ifndef FALSE
12 #define FALSE 0
13 #endif
14 #ifndef TRUE
15 #define TRUE 1
16 #endif
17
18 #define logevent(s) { logevent(s); \
19 if ((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)) \
20 fprintf(stderr, "%s\n", s); }
21
22 #define bombout(msg) ( ssh_state = SSH_STATE_CLOSED, \
23 (s ? sk_close(s), s = NULL : 0), \
24 connection_fatal msg )
25
26 #define SSH1_MSG_DISCONNECT 1 /* 0x1 */
27 #define SSH1_SMSG_PUBLIC_KEY 2 /* 0x2 */
28 #define SSH1_CMSG_SESSION_KEY 3 /* 0x3 */
29 #define SSH1_CMSG_USER 4 /* 0x4 */
30 #define SSH1_CMSG_AUTH_RSA 6 /* 0x6 */
31 #define SSH1_SMSG_AUTH_RSA_CHALLENGE 7 /* 0x7 */
32 #define SSH1_CMSG_AUTH_RSA_RESPONSE 8 /* 0x8 */
33 #define SSH1_CMSG_AUTH_PASSWORD 9 /* 0x9 */
34 #define SSH1_CMSG_REQUEST_PTY 10 /* 0xa */
35 #define SSH1_CMSG_WINDOW_SIZE 11 /* 0xb */
36 #define SSH1_CMSG_EXEC_SHELL 12 /* 0xc */
37 #define SSH1_CMSG_EXEC_CMD 13 /* 0xd */
38 #define SSH1_SMSG_SUCCESS 14 /* 0xe */
39 #define SSH1_SMSG_FAILURE 15 /* 0xf */
40 #define SSH1_CMSG_STDIN_DATA 16 /* 0x10 */
41 #define SSH1_SMSG_STDOUT_DATA 17 /* 0x11 */
42 #define SSH1_SMSG_STDERR_DATA 18 /* 0x12 */
43 #define SSH1_CMSG_EOF 19 /* 0x13 */
44 #define SSH1_SMSG_EXIT_STATUS 20 /* 0x14 */
45 #define SSH1_MSG_CHANNEL_OPEN_CONFIRMATION 21 /* 0x15 */
46 #define SSH1_MSG_CHANNEL_OPEN_FAILURE 22 /* 0x16 */
47 #define SSH1_MSG_CHANNEL_DATA 23 /* 0x17 */
48 #define SSH1_MSG_CHANNEL_CLOSE 24 /* 0x18 */
49 #define SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION 25 /* 0x19 */
50 #define SSH1_SMSG_X11_OPEN 27 /* 0x1b */
51 #define SSH1_CMSG_PORT_FORWARD_REQUEST 28 /* 0x1c */
52 #define SSH1_MSG_PORT_OPEN 29 /* 0x1d */
53 #define SSH1_CMSG_AGENT_REQUEST_FORWARDING 30 /* 0x1e */
54 #define SSH1_SMSG_AGENT_OPEN 31 /* 0x1f */
55 #define SSH1_MSG_IGNORE 32 /* 0x20 */
56 #define SSH1_CMSG_EXIT_CONFIRMATION 33 /* 0x21 */
57 #define SSH1_CMSG_X11_REQUEST_FORWARDING 34 /* 0x22 */
58 #define SSH1_CMSG_AUTH_RHOSTS_RSA 35 /* 0x23 */
59 #define SSH1_MSG_DEBUG 36 /* 0x24 */
60 #define SSH1_CMSG_REQUEST_COMPRESSION 37 /* 0x25 */
61 #define SSH1_CMSG_AUTH_TIS 39 /* 0x27 */
62 #define SSH1_SMSG_AUTH_TIS_CHALLENGE 40 /* 0x28 */
63 #define SSH1_CMSG_AUTH_TIS_RESPONSE 41 /* 0x29 */
64 #define SSH1_CMSG_AUTH_CCARD 70 /* 0x46 */
65 #define SSH1_SMSG_AUTH_CCARD_CHALLENGE 71 /* 0x47 */
66 #define SSH1_CMSG_AUTH_CCARD_RESPONSE 72 /* 0x48 */
67
68 #define SSH1_AUTH_TIS 5 /* 0x5 */
69 #define SSH1_AUTH_CCARD 16 /* 0x10 */
70
71 #define SSH1_PROTOFLAG_SCREEN_NUMBER 1 /* 0x1 */
72 /* Mask for protoflags we will echo back to server if seen */
73 #define SSH1_PROTOFLAGS_SUPPORTED 0 /* 0x1 */
74
75 #define SSH2_MSG_DISCONNECT 1 /* 0x1 */
76 #define SSH2_MSG_IGNORE 2 /* 0x2 */
77 #define SSH2_MSG_UNIMPLEMENTED 3 /* 0x3 */
78 #define SSH2_MSG_DEBUG 4 /* 0x4 */
79 #define SSH2_MSG_SERVICE_REQUEST 5 /* 0x5 */
80 #define SSH2_MSG_SERVICE_ACCEPT 6 /* 0x6 */
81 #define SSH2_MSG_KEXINIT 20 /* 0x14 */
82 #define SSH2_MSG_NEWKEYS 21 /* 0x15 */
83 #define SSH2_MSG_KEXDH_INIT 30 /* 0x1e */
84 #define SSH2_MSG_KEXDH_REPLY 31 /* 0x1f */
85 #define SSH2_MSG_KEX_DH_GEX_REQUEST 30 /* 0x1e */
86 #define SSH2_MSG_KEX_DH_GEX_GROUP 31 /* 0x1f */
87 #define SSH2_MSG_KEX_DH_GEX_INIT 32 /* 0x20 */
88 #define SSH2_MSG_KEX_DH_GEX_REPLY 33 /* 0x21 */
89 #define SSH2_MSG_USERAUTH_REQUEST 50 /* 0x32 */
90 #define SSH2_MSG_USERAUTH_FAILURE 51 /* 0x33 */
91 #define SSH2_MSG_USERAUTH_SUCCESS 52 /* 0x34 */
92 #define SSH2_MSG_USERAUTH_BANNER 53 /* 0x35 */
93 #define SSH2_MSG_USERAUTH_PK_OK 60 /* 0x3c */
94 #define SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ 60 /* 0x3c */
95 #define SSH2_MSG_GLOBAL_REQUEST 80 /* 0x50 */
96 #define SSH2_MSG_REQUEST_SUCCESS 81 /* 0x51 */
97 #define SSH2_MSG_REQUEST_FAILURE 82 /* 0x52 */
98 #define SSH2_MSG_CHANNEL_OPEN 90 /* 0x5a */
99 #define SSH2_MSG_CHANNEL_OPEN_CONFIRMATION 91 /* 0x5b */
100 #define SSH2_MSG_CHANNEL_OPEN_FAILURE 92 /* 0x5c */
101 #define SSH2_MSG_CHANNEL_WINDOW_ADJUST 93 /* 0x5d */
102 #define SSH2_MSG_CHANNEL_DATA 94 /* 0x5e */
103 #define SSH2_MSG_CHANNEL_EXTENDED_DATA 95 /* 0x5f */
104 #define SSH2_MSG_CHANNEL_EOF 96 /* 0x60 */
105 #define SSH2_MSG_CHANNEL_CLOSE 97 /* 0x61 */
106 #define SSH2_MSG_CHANNEL_REQUEST 98 /* 0x62 */
107 #define SSH2_MSG_CHANNEL_SUCCESS 99 /* 0x63 */
108 #define SSH2_MSG_CHANNEL_FAILURE 100 /* 0x64 */
109
110 #define SSH2_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT 1 /* 0x1 */
111 #define SSH2_DISCONNECT_PROTOCOL_ERROR 2 /* 0x2 */
112 #define SSH2_DISCONNECT_KEY_EXCHANGE_FAILED 3 /* 0x3 */
113 #define SSH2_DISCONNECT_HOST_AUTHENTICATION_FAILED 4 /* 0x4 */
114 #define SSH2_DISCONNECT_MAC_ERROR 5 /* 0x5 */
115 #define SSH2_DISCONNECT_COMPRESSION_ERROR 6 /* 0x6 */
116 #define SSH2_DISCONNECT_SERVICE_NOT_AVAILABLE 7 /* 0x7 */
117 #define SSH2_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED 8 /* 0x8 */
118 #define SSH2_DISCONNECT_HOST_KEY_NOT_VERIFIABLE 9 /* 0x9 */
119 #define SSH2_DISCONNECT_CONNECTION_LOST 10 /* 0xa */
120 #define SSH2_DISCONNECT_BY_APPLICATION 11 /* 0xb */
121 #define SSH2_DISCONNECT_TOO_MANY_CONNECTIONS 12 /* 0xc */
122 #define SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER 13 /* 0xd */
123 #define SSH2_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE 14 /* 0xe */
124 #define SSH2_DISCONNECT_ILLEGAL_USER_NAME 15 /* 0xf */
125
126 static const char *const ssh2_disconnect_reasons[] = {
127 NULL,
128 "SSH_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT",
129 "SSH_DISCONNECT_PROTOCOL_ERROR",
130 "SSH_DISCONNECT_KEY_EXCHANGE_FAILED",
131 "SSH_DISCONNECT_HOST_AUTHENTICATION_FAILED",
132 "SSH_DISCONNECT_MAC_ERROR",
133 "SSH_DISCONNECT_COMPRESSION_ERROR",
134 "SSH_DISCONNECT_SERVICE_NOT_AVAILABLE",
135 "SSH_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED",
136 "SSH_DISCONNECT_HOST_KEY_NOT_VERIFIABLE",
137 "SSH_DISCONNECT_CONNECTION_LOST",
138 "SSH_DISCONNECT_BY_APPLICATION",
139 "SSH_DISCONNECT_TOO_MANY_CONNECTIONS",
140 "SSH_DISCONNECT_AUTH_CANCELLED_BY_USER",
141 "SSH_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE",
142 "SSH_DISCONNECT_ILLEGAL_USER_NAME",
143 };
144
145 #define SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED 1 /* 0x1 */
146 #define SSH2_OPEN_CONNECT_FAILED 2 /* 0x2 */
147 #define SSH2_OPEN_UNKNOWN_CHANNEL_TYPE 3 /* 0x3 */
148 #define SSH2_OPEN_RESOURCE_SHORTAGE 4 /* 0x4 */
149
150 #define SSH2_EXTENDED_DATA_STDERR 1 /* 0x1 */
151
152 /*
153 * Various remote-bug flags.
154 */
155 #define BUG_CHOKES_ON_SSH1_IGNORE 1
156 #define BUG_SSH2_HMAC 2
157
158 #define GET_32BIT(cp) \
159 (((unsigned long)(unsigned char)(cp)[0] << 24) | \
160 ((unsigned long)(unsigned char)(cp)[1] << 16) | \
161 ((unsigned long)(unsigned char)(cp)[2] << 8) | \
162 ((unsigned long)(unsigned char)(cp)[3]))
163
164 #define PUT_32BIT(cp, value) { \
165 (cp)[0] = (unsigned char)((value) >> 24); \
166 (cp)[1] = (unsigned char)((value) >> 16); \
167 (cp)[2] = (unsigned char)((value) >> 8); \
168 (cp)[3] = (unsigned char)(value); }
169
170 enum { PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR, PKT_BIGNUM };
171
172 /* Coroutine mechanics for the sillier bits of the code */
173 #define crBegin1 static int crLine = 0;
174 #define crBegin2 switch(crLine) { case 0:;
175 #define crBegin crBegin1; crBegin2;
176 #define crFinish(z) } crLine = 0; return (z)
177 #define crFinishV } crLine = 0; return
178 #define crReturn(z) \
179 do {\
180 crLine=__LINE__; return (z); case __LINE__:;\
181 } while (0)
182 #define crReturnV \
183 do {\
184 crLine=__LINE__; return; case __LINE__:;\
185 } while (0)
186 #define crStop(z) do{ crLine = 0; return (z); }while(0)
187 #define crStopV do{ crLine = 0; return; }while(0)
188 #define crWaitUntil(c) do { crReturn(0); } while (!(c))
189 #define crWaitUntilV(c) do { crReturnV; } while (!(c))
190
191 extern char *x11_init (Socket *, char *, void *);
192 extern void x11_close (Socket);
193 extern void x11_send (Socket , char *, int);
194 extern void x11_invent_auth(char *, int, char *, int);
195
196 /*
197 * Ciphers for SSH2. We miss out single-DES because it isn't
198 * supported; also 3DES and Blowfish are both done differently from
199 * SSH1. (3DES uses outer chaining; Blowfish has the opposite
200 * endianness and different-sized keys.)
201 */
202 const static struct ssh2_ciphers *ciphers[] = {
203 &ssh2_aes,
204 &ssh2_blowfish,
205 &ssh2_3des,
206 };
207
208 const static struct ssh_kex *kex_algs[] = {
209 &ssh_diffiehellman_gex,
210 &ssh_diffiehellman };
211
212 const static struct ssh_signkey *hostkey_algs[] = { &ssh_rsa, &ssh_dss };
213
214 static void nullmac_key(unsigned char *key) { }
215 static void nullmac_generate(unsigned char *blk, int len, unsigned long seq) { }
216 static int nullmac_verify(unsigned char *blk, int len, unsigned long seq) { return 1; }
217 const static struct ssh_mac ssh_mac_none = {
218 nullmac_key, nullmac_key, nullmac_generate, nullmac_verify, "none", 0
219 };
220 const static struct ssh_mac *macs[] = {
221 &ssh_sha1, &ssh_md5, &ssh_mac_none };
222 const static struct ssh_mac *buggymacs[] = {
223 &ssh_sha1_buggy, &ssh_md5, &ssh_mac_none };
224
225 static void ssh_comp_none_init(void) { }
226 static int ssh_comp_none_block(unsigned char *block, int len,
227 unsigned char **outblock, int *outlen) {
228 return 0;
229 }
230 static int ssh_comp_none_disable(void) { return 0; }
231 const static struct ssh_compress ssh_comp_none = {
232 "none",
233 ssh_comp_none_init, ssh_comp_none_block,
234 ssh_comp_none_init, ssh_comp_none_block,
235 ssh_comp_none_disable
236 };
237 extern const struct ssh_compress ssh_zlib;
238 const static struct ssh_compress *compressions[] = {
239 &ssh_zlib, &ssh_comp_none };
240
241 enum { /* channel types */
242 CHAN_MAINSESSION,
243 CHAN_X11,
244 CHAN_AGENT,
245 };
246
247 /*
248 * 2-3-4 tree storing channels.
249 */
250 struct ssh_channel {
251 unsigned remoteid, localid;
252 int type;
253 int closes;
254 struct ssh2_data_channel {
255 unsigned char *outbuffer;
256 unsigned outbuflen, outbufsize;
257 unsigned remwindow, remmaxpkt;
258 } v2;
259 union {
260 struct ssh_agent_channel {
261 unsigned char *message;
262 unsigned char msglen[4];
263 int lensofar, totallen;
264 } a;
265 struct ssh_x11_channel {
266 Socket s;
267 } x11;
268 } u;
269 };
270
271 struct Packet {
272 long length;
273 int type;
274 unsigned char *data;
275 unsigned char *body;
276 long savedpos;
277 long maxlen;
278 };
279
280 static SHA_State exhash, exhashbase;
281
282 static Socket s = NULL;
283
284 static unsigned char session_key[32];
285 static int ssh1_compressing;
286 static int ssh1_remote_protoflags;
287 static int ssh1_local_protoflags;
288 static int ssh_agentfwd_enabled;
289 static int ssh_X11_fwd_enabled;
290 static int ssh_remote_bugs;
291 static const struct ssh_cipher *cipher = NULL;
292 static const struct ssh2_cipher *cscipher = NULL;
293 static const struct ssh2_cipher *sccipher = NULL;
294 static const struct ssh_mac *csmac = NULL;
295 static const struct ssh_mac *scmac = NULL;
296 static const struct ssh_compress *cscomp = NULL;
297 static const struct ssh_compress *sccomp = NULL;
298 static const struct ssh_kex *kex = NULL;
299 static const struct ssh_signkey *hostkey = NULL;
300 static unsigned char ssh2_session_id[20];
301 int (*ssh_get_line)(const char *prompt, char *str, int maxlen,
302 int is_pw) = NULL;
303
304 static char *savedhost;
305 static int savedport;
306 static int ssh_send_ok;
307 static int ssh_echoing, ssh_editing;
308
309 static tree234 *ssh_channels; /* indexed by local id */
310 static struct ssh_channel *mainchan; /* primary session channel */
311
312 static enum {
313 SSH_STATE_PREPACKET,
314 SSH_STATE_BEFORE_SIZE,
315 SSH_STATE_INTERMED,
316 SSH_STATE_SESSION,
317 SSH_STATE_CLOSED
318 } ssh_state = SSH_STATE_PREPACKET;
319
320 static int size_needed = FALSE, eof_needed = FALSE;
321
322 static struct Packet pktin = { 0, 0, NULL, NULL, 0 };
323 static struct Packet pktout = { 0, 0, NULL, NULL, 0 };
324 static unsigned char *deferred_send_data = NULL;
325 static int deferred_len = 0, deferred_size = 0;
326
327 static int ssh_version;
328 static void (*ssh_protocol)(unsigned char *in, int inlen, int ispkt);
329 static void ssh1_protocol(unsigned char *in, int inlen, int ispkt);
330 static void ssh2_protocol(unsigned char *in, int inlen, int ispkt);
331 static void ssh_size(void);
332 static void ssh_special (Telnet_Special);
333 static void ssh2_try_send(struct ssh_channel *c);
334 static void ssh2_add_channel_data(struct ssh_channel *c, char *buf, int len);
335
336 static int (*s_rdpkt)(unsigned char **data, int *datalen);
337
338 static struct rdpkt1_state_tag {
339 long len, pad, biglen, to_read;
340 unsigned long realcrc, gotcrc;
341 unsigned char *p;
342 int i;
343 int chunk;
344 } rdpkt1_state;
345
346 static struct rdpkt2_state_tag {
347 long len, pad, payload, packetlen, maclen;
348 int i;
349 int cipherblk;
350 unsigned long incoming_sequence;
351 } rdpkt2_state;
352
353 static int ssh_channelcmp(void *av, void *bv) {
354 struct ssh_channel *a = (struct ssh_channel *)av;
355 struct ssh_channel *b = (struct ssh_channel *)bv;
356 if (a->localid < b->localid) return -1;
357 if (a->localid > b->localid) return +1;
358 return 0;
359 }
360 static int ssh_channelfind(void *av, void *bv) {
361 unsigned *a = (unsigned *)av;
362 struct ssh_channel *b = (struct ssh_channel *)bv;
363 if (*a < b->localid) return -1;
364 if (*a > b->localid) return +1;
365 return 0;
366 }
367
368 static int alloc_channel_id(void) {
369 const unsigned CHANNEL_NUMBER_OFFSET = 256;
370 unsigned low, high, mid;
371 int tsize;
372 struct ssh_channel *c;
373
374 /*
375 * First-fit allocation of channel numbers: always pick the
376 * lowest unused one. To do this, binary-search using the
377 * counted B-tree to find the largest channel ID which is in a
378 * contiguous sequence from the beginning. (Precisely
379 * everything in that sequence must have ID equal to its tree
380 * index plus CHANNEL_NUMBER_OFFSET.)
381 */
382 tsize = count234(ssh_channels);
383
384 low = -1; high = tsize;
385 while (high - low > 1) {
386 mid = (high + low) / 2;
387 c = index234(ssh_channels, mid);
388 if (c->localid == mid + CHANNEL_NUMBER_OFFSET)
389 low = mid; /* this one is fine */
390 else
391 high = mid; /* this one is past it */
392 }
393 /*
394 * Now low points to either -1, or the tree index of the
395 * largest ID in the initial sequence.
396 */
397 {
398 unsigned i = low + 1 + CHANNEL_NUMBER_OFFSET;
399 assert(NULL == find234(ssh_channels, &i, ssh_channelfind));
400 }
401 return low + 1 + CHANNEL_NUMBER_OFFSET;
402 }
403
404 static void c_write (char *buf, int len) {
405 if ((flags & FLAG_STDERR)) {
406 int i;
407 for (i = 0; i < len; i++)
408 if (buf[i] != '\r')
409 fputc(buf[i], stderr);
410 return;
411 }
412 from_backend(1, buf, len);
413 }
414
415 static void c_write_untrusted(char *buf, int len) {
416 int i;
417 for (i = 0; i < len; i++) {
418 if (buf[i] == '\n')
419 c_write("\r\n", 2);
420 else if ((buf[i] & 0x60) || (buf[i] == '\r'))
421 c_write(buf+i, 1);
422 }
423 }
424
425 static void c_write_str (char *buf) {
426 c_write(buf, strlen(buf));
427 }
428
429 /*
430 * Collect incoming data in the incoming packet buffer.
431 * Decipher and verify the packet when it is completely read.
432 * Drop SSH1_MSG_DEBUG and SSH1_MSG_IGNORE packets.
433 * Update the *data and *datalen variables.
434 * Return the additional nr of bytes needed, or 0 when
435 * a complete packet is available.
436 */
437 static int ssh1_rdpkt(unsigned char **data, int *datalen)
438 {
439 struct rdpkt1_state_tag *st = &rdpkt1_state;
440
441 crBegin;
442
443 next_packet:
444
445 pktin.type = 0;
446 pktin.length = 0;
447
448 for (st->i = st->len = 0; st->i < 4; st->i++) {
449 while ((*datalen) == 0)
450 crReturn(4-st->i);
451 st->len = (st->len << 8) + **data;
452 (*data)++, (*datalen)--;
453 }
454
455 #ifdef FWHACK
456 if (st->len == 0x52656d6f) { /* "Remo"te server has closed ... */
457 st->len = 0x300; /* big enough to carry to end */
458 }
459 #endif
460
461 st->pad = 8 - (st->len % 8);
462 st->biglen = st->len + st->pad;
463 pktin.length = st->len - 5;
464
465 if (pktin.maxlen < st->biglen) {
466 pktin.maxlen = st->biglen;
467 pktin.data = (pktin.data == NULL ? smalloc(st->biglen+APIEXTRA) :
468 srealloc(pktin.data, st->biglen+APIEXTRA));
469 if (!pktin.data)
470 fatalbox("Out of memory");
471 }
472
473 st->to_read = st->biglen;
474 st->p = pktin.data;
475 while (st->to_read > 0) {
476 st->chunk = st->to_read;
477 while ((*datalen) == 0)
478 crReturn(st->to_read);
479 if (st->chunk > (*datalen))
480 st->chunk = (*datalen);
481 memcpy(st->p, *data, st->chunk);
482 *data += st->chunk;
483 *datalen -= st->chunk;
484 st->p += st->chunk;
485 st->to_read -= st->chunk;
486 }
487
488 if (cipher)
489 cipher->decrypt(pktin.data, st->biglen);
490 #if 0
491 debug(("Got packet len=%d pad=%d\r\n", st->len, st->pad));
492 for (st->i = 0; st->i < st->biglen; st->i++)
493 debug((" %02x", (unsigned char)pktin.data[st->i]));
494 debug(("\r\n"));
495 #endif
496
497 st->realcrc = crc32(pktin.data, st->biglen-4);
498 st->gotcrc = GET_32BIT(pktin.data+st->biglen-4);
499 if (st->gotcrc != st->realcrc) {
500 bombout(("Incorrect CRC received on packet"));
501 crReturn(0);
502 }
503
504 pktin.body = pktin.data + st->pad + 1;
505
506 if (ssh1_compressing) {
507 unsigned char *decompblk;
508 int decomplen;
509 #if 0
510 {
511 int i;
512 debug(("Packet payload pre-decompression:\n"));
513 for (i = -1; i < pktin.length; i++)
514 debug((" %02x", (unsigned char)pktin.body[i]));
515 debug(("\r\n"));
516 }
517 #endif
518 zlib_decompress_block(pktin.body-1, pktin.length+1,
519 &decompblk, &decomplen);
520
521 if (pktin.maxlen < st->pad + decomplen) {
522 pktin.maxlen = st->pad + decomplen;
523 pktin.data = srealloc(pktin.data, pktin.maxlen+APIEXTRA);
524 pktin.body = pktin.data + st->pad + 1;
525 if (!pktin.data)
526 fatalbox("Out of memory");
527 }
528
529 memcpy(pktin.body-1, decompblk, decomplen);
530 sfree(decompblk);
531 pktin.length = decomplen-1;
532 #if 0
533 {
534 int i;
535 debug(("Packet payload post-decompression:\n"));
536 for (i = -1; i < pktin.length; i++)
537 debug((" %02x", (unsigned char)pktin.body[i]));
538 debug(("\r\n"));
539 }
540 #endif
541 }
542
543 if (pktin.type == SSH1_SMSG_STDOUT_DATA ||
544 pktin.type == SSH1_SMSG_STDERR_DATA ||
545 pktin.type == SSH1_MSG_DEBUG ||
546 pktin.type == SSH1_SMSG_AUTH_TIS_CHALLENGE ||
547 pktin.type == SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
548 long strlen = GET_32BIT(pktin.body);
549 if (strlen + 4 != pktin.length) {
550 bombout(("Received data packet with bogus string length"));
551 crReturn(0);
552 }
553 }
554
555 pktin.type = pktin.body[-1];
556
557 if (pktin.type == SSH1_MSG_DEBUG) {
558 /* log debug message */
559 char buf[80];
560 int strlen = GET_32BIT(pktin.body);
561 strcpy(buf, "Remote: ");
562 if (strlen > 70) strlen = 70;
563 memcpy(buf+8, pktin.body+4, strlen);
564 buf[8+strlen] = '\0';
565 logevent(buf);
566 goto next_packet;
567 } else if (pktin.type == SSH1_MSG_IGNORE) {
568 /* do nothing */
569 goto next_packet;
570 }
571
572 if (pktin.type == SSH1_MSG_DISCONNECT) {
573 /* log reason code in disconnect message */
574 char buf[256];
575 unsigned msglen = GET_32BIT(pktin.body);
576 unsigned nowlen;
577 strcpy(buf, "Remote sent disconnect: ");
578 nowlen = strlen(buf);
579 if (msglen > sizeof(buf)-nowlen-1)
580 msglen = sizeof(buf)-nowlen-1;
581 memcpy(buf+nowlen, pktin.body+4, msglen);
582 buf[nowlen+msglen] = '\0';
583 logevent(buf);
584 }
585
586 crFinish(0);
587 }
588
589 static int ssh2_rdpkt(unsigned char **data, int *datalen)
590 {
591 struct rdpkt2_state_tag *st = &rdpkt2_state;
592
593 crBegin;
594
595 next_packet:
596 pktin.type = 0;
597 pktin.length = 0;
598 if (sccipher)
599 st->cipherblk = sccipher->blksize;
600 else
601 st->cipherblk = 8;
602 if (st->cipherblk < 8)
603 st->cipherblk = 8;
604
605 if (pktin.maxlen < st->cipherblk) {
606 pktin.maxlen = st->cipherblk;
607 pktin.data = (pktin.data == NULL ? smalloc(st->cipherblk+APIEXTRA) :
608 srealloc(pktin.data, st->cipherblk+APIEXTRA));
609 if (!pktin.data)
610 fatalbox("Out of memory");
611 }
612
613 /*
614 * Acquire and decrypt the first block of the packet. This will
615 * contain the length and padding details.
616 */
617 for (st->i = st->len = 0; st->i < st->cipherblk; st->i++) {
618 while ((*datalen) == 0)
619 crReturn(st->cipherblk-st->i);
620 pktin.data[st->i] = *(*data)++;
621 (*datalen)--;
622 }
623 #ifdef FWHACK
624 if (!memcmp(pktin.data, "Remo", 4)) {/* "Remo"te server has closed ... */
625 /* FIXME */
626 }
627 #endif
628 if (sccipher)
629 sccipher->decrypt(pktin.data, st->cipherblk);
630
631 /*
632 * Now get the length and padding figures.
633 */
634 st->len = GET_32BIT(pktin.data);
635 st->pad = pktin.data[4];
636
637 /*
638 * This enables us to deduce the payload length.
639 */
640 st->payload = st->len - st->pad - 1;
641
642 pktin.length = st->payload + 5;
643
644 /*
645 * So now we can work out the total packet length.
646 */
647 st->packetlen = st->len + 4;
648 st->maclen = scmac ? scmac->len : 0;
649
650 /*
651 * Adjust memory allocation if packet is too big.
652 */
653 if (pktin.maxlen < st->packetlen+st->maclen) {
654 pktin.maxlen = st->packetlen+st->maclen;
655 pktin.data = (pktin.data == NULL ? smalloc(pktin.maxlen+APIEXTRA) :
656 srealloc(pktin.data, pktin.maxlen+APIEXTRA));
657 if (!pktin.data)
658 fatalbox("Out of memory");
659 }
660
661 /*
662 * Read and decrypt the remainder of the packet.
663 */
664 for (st->i = st->cipherblk; st->i < st->packetlen + st->maclen; st->i++) {
665 while ((*datalen) == 0)
666 crReturn(st->packetlen + st->maclen - st->i);
667 pktin.data[st->i] = *(*data)++;
668 (*datalen)--;
669 }
670 /* Decrypt everything _except_ the MAC. */
671 if (sccipher)
672 sccipher->decrypt(pktin.data + st->cipherblk,
673 st->packetlen - st->cipherblk);
674
675 #if 0
676 debug(("Got packet len=%d pad=%d\r\n", st->len, st->pad));
677 for (st->i = 0; st->i < st->packetlen; st->i++)
678 debug((" %02x", (unsigned char)pktin.data[st->i]));
679 debug(("\r\n"));
680 #endif
681
682 /*
683 * Check the MAC.
684 */
685 if (scmac && !scmac->verify(pktin.data, st->len+4, st->incoming_sequence)) {
686 bombout(("Incorrect MAC received on packet"));
687 crReturn(0);
688 }
689 st->incoming_sequence++; /* whether or not we MACed */
690
691 /*
692 * Decompress packet payload.
693 */
694 {
695 unsigned char *newpayload;
696 int newlen;
697 if (sccomp && sccomp->decompress(pktin.data+5, pktin.length-5,
698 &newpayload, &newlen)) {
699 if (pktin.maxlen < newlen+5) {
700 pktin.maxlen = newlen+5;
701 pktin.data = (pktin.data == NULL ? smalloc(pktin.maxlen+APIEXTRA) :
702 srealloc(pktin.data, pktin.maxlen+APIEXTRA));
703 if (!pktin.data)
704 fatalbox("Out of memory");
705 }
706 pktin.length = 5 + newlen;
707 memcpy(pktin.data+5, newpayload, newlen);
708 #if 0
709 debug(("Post-decompression payload:\r\n"));
710 for (st->i = 0; st->i < newlen; st->i++)
711 debug((" %02x", (unsigned char)pktin.data[5+st->i]));
712 debug(("\r\n"));
713 #endif
714
715 sfree(newpayload);
716 }
717 }
718
719 pktin.savedpos = 6;
720 pktin.type = pktin.data[5];
721
722 if (pktin.type == SSH2_MSG_IGNORE || pktin.type == SSH2_MSG_DEBUG)
723 goto next_packet; /* FIXME: print DEBUG message */
724
725 if (pktin.type == SSH2_MSG_DISCONNECT) {
726 /* log reason code in disconnect message */
727 char buf[256];
728 int reason = GET_32BIT(pktin.data+6);
729 unsigned msglen = GET_32BIT(pktin.data+10);
730 unsigned nowlen;
731 if (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) {
732 sprintf(buf, "Received disconnect message (%s)",
733 ssh2_disconnect_reasons[reason]);
734 } else {
735 sprintf(buf, "Received disconnect message (unknown type %d)", reason);
736 }
737 logevent(buf);
738 strcpy(buf, "Disconnection message text: ");
739 nowlen = strlen(buf);
740 if (msglen > sizeof(buf)-nowlen-1)
741 msglen = sizeof(buf)-nowlen-1;
742 memcpy(buf+nowlen, pktin.data+14, msglen);
743 buf[nowlen+msglen] = '\0';
744 logevent(buf);
745 }
746
747 crFinish(0);
748 }
749
750 static void ssh1_pktout_size(int len) {
751 int pad, biglen;
752
753 len += 5; /* type and CRC */
754 pad = 8 - (len%8);
755 biglen = len + pad;
756
757 pktout.length = len-5;
758 if (pktout.maxlen < biglen) {
759 pktout.maxlen = biglen;
760 #ifdef MSCRYPTOAPI
761 /* Allocate enough buffer space for extra block
762 * for MS CryptEncrypt() */
763 pktout.data = (pktout.data == NULL ? smalloc(biglen+12) :
764 srealloc(pktout.data, biglen+12));
765 #else
766 pktout.data = (pktout.data == NULL ? smalloc(biglen+4) :
767 srealloc(pktout.data, biglen+4));
768 #endif
769 if (!pktout.data)
770 fatalbox("Out of memory");
771 }
772 pktout.body = pktout.data+4+pad+1;
773 }
774
775 static void s_wrpkt_start(int type, int len) {
776 ssh1_pktout_size(len);
777 pktout.type = type;
778 }
779
780 static int s_wrpkt_prepare(void) {
781 int pad, len, biglen, i;
782 unsigned long crc;
783
784 pktout.body[-1] = pktout.type;
785
786 #if 0
787 debug(("Packet payload pre-compression:\n"));
788 for (i = -1; i < pktout.length; i++)
789 debug((" %02x", (unsigned char)pktout.body[i]));
790 debug(("\r\n"));
791 #endif
792
793 if (ssh1_compressing) {
794 unsigned char *compblk;
795 int complen;
796 zlib_compress_block(pktout.body-1, pktout.length+1,
797 &compblk, &complen);
798 ssh1_pktout_size(complen-1);
799 memcpy(pktout.body-1, compblk, complen);
800 sfree(compblk);
801 #if 0
802 debug(("Packet payload post-compression:\n"));
803 for (i = -1; i < pktout.length; i++)
804 debug((" %02x", (unsigned char)pktout.body[i]));
805 debug(("\r\n"));
806 #endif
807 }
808
809 len = pktout.length + 5; /* type and CRC */
810 pad = 8 - (len%8);
811 biglen = len + pad;
812
813 for (i=0; i<pad; i++)
814 pktout.data[i+4] = random_byte();
815 crc = crc32(pktout.data+4, biglen-4);
816 PUT_32BIT(pktout.data+biglen, crc);
817 PUT_32BIT(pktout.data, len);
818
819 #if 0
820 debug(("Sending packet len=%d\r\n", biglen+4));
821 for (i = 0; i < biglen+4; i++)
822 debug((" %02x", (unsigned char)pktout.data[i]));
823 debug(("\r\n"));
824 #endif
825 if (cipher)
826 cipher->encrypt(pktout.data+4, biglen);
827
828 return biglen+4;
829 }
830
831 static void s_wrpkt(void) {
832 int len;
833 len = s_wrpkt_prepare();
834 sk_write(s, pktout.data, len);
835 }
836
837 static void s_wrpkt_defer(void) {
838 int len;
839 len = s_wrpkt_prepare();
840 if (deferred_len + len > deferred_size) {
841 deferred_size = deferred_len + len + 128;
842 deferred_send_data = srealloc(deferred_send_data, deferred_size);
843 }
844 memcpy(deferred_send_data+deferred_len, pktout.data, len);
845 deferred_len += len;
846 }
847
848 /*
849 * Construct a packet with the specified contents.
850 */
851 static void construct_packet(int pkttype, va_list ap1, va_list ap2)
852 {
853 unsigned char *p, *argp, argchar;
854 unsigned long argint;
855 int pktlen, argtype, arglen;
856 Bignum bn;
857
858 pktlen = 0;
859 while ((argtype = va_arg(ap1, int)) != PKT_END) {
860 switch (argtype) {
861 case PKT_INT:
862 (void) va_arg(ap1, int);
863 pktlen += 4;
864 break;
865 case PKT_CHAR:
866 (void) va_arg(ap1, char);
867 pktlen++;
868 break;
869 case PKT_DATA:
870 (void) va_arg(ap1, unsigned char *);
871 arglen = va_arg(ap1, int);
872 pktlen += arglen;
873 break;
874 case PKT_STR:
875 argp = va_arg(ap1, unsigned char *);
876 arglen = strlen(argp);
877 pktlen += 4 + arglen;
878 break;
879 case PKT_BIGNUM:
880 bn = va_arg(ap1, Bignum);
881 pktlen += ssh1_bignum_length(bn);
882 break;
883 default:
884 assert(0);
885 }
886 }
887
888 s_wrpkt_start(pkttype, pktlen);
889 p = pktout.body;
890
891 while ((argtype = va_arg(ap2, int)) != PKT_END) {
892 switch (argtype) {
893 case PKT_INT:
894 argint = va_arg(ap2, int);
895 PUT_32BIT(p, argint);
896 p += 4;
897 break;
898 case PKT_CHAR:
899 argchar = va_arg(ap2, unsigned char);
900 *p = argchar;
901 p++;
902 break;
903 case PKT_DATA:
904 argp = va_arg(ap2, unsigned char *);
905 arglen = va_arg(ap2, int);
906 memcpy(p, argp, arglen);
907 p += arglen;
908 break;
909 case PKT_STR:
910 argp = va_arg(ap2, unsigned char *);
911 arglen = strlen(argp);
912 PUT_32BIT(p, arglen);
913 memcpy(p + 4, argp, arglen);
914 p += 4 + arglen;
915 break;
916 case PKT_BIGNUM:
917 bn = va_arg(ap2, Bignum);
918 p += ssh1_write_bignum(p, bn);
919 break;
920 }
921 }
922 }
923
924 static void send_packet(int pkttype, ...) {
925 va_list ap1, ap2;
926 va_start(ap1, pkttype);
927 va_start(ap2, pkttype);
928 construct_packet(pkttype, ap1, ap2);
929 s_wrpkt();
930 }
931
932 static void defer_packet(int pkttype, ...) {
933 va_list ap1, ap2;
934 va_start(ap1, pkttype);
935 va_start(ap2, pkttype);
936 construct_packet(pkttype, ap1, ap2);
937 s_wrpkt_defer();
938 }
939
940 static int ssh_versioncmp(char *a, char *b) {
941 char *ae, *be;
942 unsigned long av, bv;
943
944 av = strtoul(a, &ae, 10);
945 bv = strtoul(b, &be, 10);
946 if (av != bv) return (av < bv ? -1 : +1);
947 if (*ae == '.') ae++;
948 if (*be == '.') be++;
949 av = strtoul(ae, &ae, 10);
950 bv = strtoul(be, &be, 10);
951 if (av != bv) return (av < bv ? -1 : +1);
952 return 0;
953 }
954
955
956 /*
957 * Utility routines for putting an SSH-protocol `string' and
958 * `uint32' into a SHA state.
959 */
960 #include <stdio.h>
961 static void sha_string(SHA_State *s, void *str, int len) {
962 unsigned char lenblk[4];
963 PUT_32BIT(lenblk, len);
964 SHA_Bytes(s, lenblk, 4);
965 SHA_Bytes(s, str, len);
966 }
967
968 static void sha_uint32(SHA_State *s, unsigned i) {
969 unsigned char intblk[4];
970 PUT_32BIT(intblk, i);
971 SHA_Bytes(s, intblk, 4);
972 }
973
974 /*
975 * SSH2 packet construction functions.
976 */
977 static void ssh2_pkt_ensure(int length) {
978 if (pktout.maxlen < length) {
979 pktout.maxlen = length + 256;
980 pktout.data = (pktout.data == NULL ? smalloc(pktout.maxlen+APIEXTRA) :
981 srealloc(pktout.data, pktout.maxlen+APIEXTRA));
982 if (!pktout.data)
983 fatalbox("Out of memory");
984 }
985 }
986 static void ssh2_pkt_adddata(void *data, int len) {
987 pktout.length += len;
988 ssh2_pkt_ensure(pktout.length);
989 memcpy(pktout.data+pktout.length-len, data, len);
990 }
991 static void ssh2_pkt_addbyte(unsigned char byte) {
992 ssh2_pkt_adddata(&byte, 1);
993 }
994 static void ssh2_pkt_init(int pkt_type) {
995 pktout.length = 5;
996 ssh2_pkt_addbyte((unsigned char)pkt_type);
997 }
998 static void ssh2_pkt_addbool(unsigned char value) {
999 ssh2_pkt_adddata(&value, 1);
1000 }
1001 static void ssh2_pkt_adduint32(unsigned long value) {
1002 unsigned char x[4];
1003 PUT_32BIT(x, value);
1004 ssh2_pkt_adddata(x, 4);
1005 }
1006 static void ssh2_pkt_addstring_start(void) {
1007 ssh2_pkt_adduint32(0);
1008 pktout.savedpos = pktout.length;
1009 }
1010 static void ssh2_pkt_addstring_str(char *data) {
1011 ssh2_pkt_adddata(data, strlen(data));
1012 PUT_32BIT(pktout.data + pktout.savedpos - 4,
1013 pktout.length - pktout.savedpos);
1014 }
1015 static void ssh2_pkt_addstring_data(char *data, int len) {
1016 ssh2_pkt_adddata(data, len);
1017 PUT_32BIT(pktout.data + pktout.savedpos - 4,
1018 pktout.length - pktout.savedpos);
1019 }
1020 static void ssh2_pkt_addstring(char *data) {
1021 ssh2_pkt_addstring_start();
1022 ssh2_pkt_addstring_str(data);
1023 }
1024 static char *ssh2_mpint_fmt(Bignum b, int *len) {
1025 unsigned char *p;
1026 int i, n = (bignum_bitcount(b)+7)/8;
1027 p = smalloc(n + 1);
1028 if (!p)
1029 fatalbox("out of memory");
1030 p[0] = 0;
1031 for (i = 1; i <= n; i++)
1032 p[i] = bignum_byte(b, n-i);
1033 i = 0;
1034 while (i <= n && p[i] == 0 && (p[i+1] & 0x80) == 0)
1035 i++;
1036 memmove(p, p+i, n+1-i);
1037 *len = n+1-i;
1038 return p;
1039 }
1040 static void ssh2_pkt_addmp(Bignum b) {
1041 unsigned char *p;
1042 int len;
1043 p = ssh2_mpint_fmt(b, &len);
1044 ssh2_pkt_addstring_start();
1045 ssh2_pkt_addstring_data(p, len);
1046 sfree(p);
1047 }
1048
1049 /*
1050 * Construct an SSH2 final-form packet: compress it, encrypt it,
1051 * put the MAC on it. Final packet, ready to be sent, is stored in
1052 * pktout.data. Total length is returned.
1053 */
1054 static int ssh2_pkt_construct(void) {
1055 int cipherblk, maclen, padding, i;
1056 static unsigned long outgoing_sequence = 0;
1057
1058 /*
1059 * Compress packet payload.
1060 */
1061 #if 0
1062 debug(("Pre-compression payload:\r\n"));
1063 for (i = 5; i < pktout.length; i++)
1064 debug((" %02x", (unsigned char)pktout.data[i]));
1065 debug(("\r\n"));
1066 #endif
1067 {
1068 unsigned char *newpayload;
1069 int newlen;
1070 if (cscomp && cscomp->compress(pktout.data+5, pktout.length-5,
1071 &newpayload, &newlen)) {
1072 pktout.length = 5;
1073 ssh2_pkt_adddata(newpayload, newlen);
1074 sfree(newpayload);
1075 }
1076 }
1077
1078 /*
1079 * Add padding. At least four bytes, and must also bring total
1080 * length (minus MAC) up to a multiple of the block size.
1081 */
1082 cipherblk = cscipher ? cscipher->blksize : 8; /* block size */
1083 cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */
1084 padding = 4;
1085 padding += (cipherblk - (pktout.length + padding) % cipherblk) % cipherblk;
1086 maclen = csmac ? csmac->len : 0;
1087 ssh2_pkt_ensure(pktout.length + padding + maclen);
1088 pktout.data[4] = padding;
1089 for (i = 0; i < padding; i++)
1090 pktout.data[pktout.length + i] = random_byte();
1091 PUT_32BIT(pktout.data, pktout.length + padding - 4);
1092 if (csmac)
1093 csmac->generate(pktout.data, pktout.length + padding,
1094 outgoing_sequence);
1095 outgoing_sequence++; /* whether or not we MACed */
1096
1097 #if 0
1098 debug(("Sending packet len=%d\r\n", pktout.length+padding));
1099 for (i = 0; i < pktout.length+padding; i++)
1100 debug((" %02x", (unsigned char)pktout.data[i]));
1101 debug(("\r\n"));
1102 #endif
1103
1104 if (cscipher)
1105 cscipher->encrypt(pktout.data, pktout.length + padding);
1106
1107 /* Ready-to-send packet starts at pktout.data. We return length. */
1108 return pktout.length + padding + maclen;
1109 }
1110
1111 /*
1112 * Construct and send an SSH2 packet immediately.
1113 */
1114 static void ssh2_pkt_send(void) {
1115 int len = ssh2_pkt_construct();
1116 sk_write(s, pktout.data, len);
1117 }
1118
1119 /*
1120 * Construct an SSH2 packet and add it to a deferred data block.
1121 * Useful for sending multiple packets in a single sk_write() call,
1122 * to prevent a traffic-analysing listener from being able to work
1123 * out the length of any particular packet (such as the password
1124 * packet).
1125 *
1126 * Note that because SSH2 sequence-numbers its packets, this can
1127 * NOT be used as an m4-style `defer' allowing packets to be
1128 * constructed in one order and sent in another.
1129 */
1130 static void ssh2_pkt_defer(void) {
1131 int len = ssh2_pkt_construct();
1132 if (deferred_len + len > deferred_size) {
1133 deferred_size = deferred_len + len + 128;
1134 deferred_send_data = srealloc(deferred_send_data, deferred_size);
1135 }
1136 memcpy(deferred_send_data+deferred_len, pktout.data, len);
1137 deferred_len += len;
1138 }
1139
1140 /*
1141 * Send the whole deferred data block constructed by
1142 * ssh2_pkt_defer() or SSH1's defer_packet().
1143 */
1144 static void ssh_pkt_defersend(void) {
1145 sk_write(s, deferred_send_data, deferred_len);
1146 deferred_len = deferred_size = 0;
1147 sfree(deferred_send_data);
1148 deferred_send_data = NULL;
1149 }
1150
1151 #if 0
1152 void bndebug(char *string, Bignum b) {
1153 unsigned char *p;
1154 int i, len;
1155 p = ssh2_mpint_fmt(b, &len);
1156 debug(("%s", string));
1157 for (i = 0; i < len; i++)
1158 debug((" %02x", p[i]));
1159 debug(("\r\n"));
1160 sfree(p);
1161 }
1162 #endif
1163
1164 static void sha_mpint(SHA_State *s, Bignum b) {
1165 unsigned char *p;
1166 int len;
1167 p = ssh2_mpint_fmt(b, &len);
1168 sha_string(s, p, len);
1169 sfree(p);
1170 }
1171
1172 /*
1173 * SSH2 packet decode functions.
1174 */
1175 static unsigned long ssh2_pkt_getuint32(void) {
1176 unsigned long value;
1177 if (pktin.length - pktin.savedpos < 4)
1178 return 0; /* arrgh, no way to decline (FIXME?) */
1179 value = GET_32BIT(pktin.data+pktin.savedpos);
1180 pktin.savedpos += 4;
1181 return value;
1182 }
1183 static int ssh2_pkt_getbool(void) {
1184 unsigned long value;
1185 if (pktin.length - pktin.savedpos < 1)
1186 return 0; /* arrgh, no way to decline (FIXME?) */
1187 value = pktin.data[pktin.savedpos] != 0;
1188 pktin.savedpos++;
1189 return value;
1190 }
1191 static void ssh2_pkt_getstring(char **p, int *length) {
1192 *p = NULL;
1193 if (pktin.length - pktin.savedpos < 4)
1194 return;
1195 *length = GET_32BIT(pktin.data+pktin.savedpos);
1196 pktin.savedpos += 4;
1197 if (pktin.length - pktin.savedpos < *length)
1198 return;
1199 *p = pktin.data+pktin.savedpos;
1200 pktin.savedpos += *length;
1201 }
1202 static Bignum ssh2_pkt_getmp(void) {
1203 char *p;
1204 int length;
1205 Bignum b;
1206
1207 ssh2_pkt_getstring(&p, &length);
1208 if (!p)
1209 return NULL;
1210 if (p[0] & 0x80) {
1211 bombout(("internal error: Can't handle negative mpints"));
1212 return NULL;
1213 }
1214 b = bignum_from_bytes(p, length);
1215 return b;
1216 }
1217
1218 /*
1219 * Examine the remote side's version string and compare it against
1220 * a list of known buggy implementations.
1221 */
1222 static void ssh_detect_bugs(char *vstring) {
1223 char *imp; /* pointer to implementation part */
1224 imp = vstring;
1225 imp += strcspn(imp, "-");
1226 if (*imp) imp++;
1227 imp += strcspn(imp, "-");
1228 if (*imp) imp++;
1229
1230 ssh_remote_bugs = 0;
1231
1232 if (!strcmp(imp, "1.2.18") || !strcmp(imp, "1.2.19") ||
1233 !strcmp(imp, "1.2.20") || !strcmp(imp, "1.2.21") ||
1234 !strcmp(imp, "1.2.22")) {
1235 /*
1236 * These versions don't support SSH1_MSG_IGNORE, so we have
1237 * to use a different defence against password length
1238 * sniffing.
1239 */
1240 ssh_remote_bugs |= BUG_CHOKES_ON_SSH1_IGNORE;
1241 logevent("We believe remote version has SSH1 ignore bug");
1242 }
1243
1244 if (!strncmp(imp, "2.1.0", 5) || !strncmp(imp, "2.0.", 4) ||
1245 !strncmp(imp, "2.2.0", 5) || !strncmp(imp, "2.3.0", 5) ||
1246 !strncmp(imp, "2.1 ", 4)) {
1247 /*
1248 * These versions have the HMAC bug.
1249 */
1250 ssh_remote_bugs |= BUG_SSH2_HMAC;
1251 logevent("We believe remote version has SSH2 HMAC bug");
1252 }
1253 }
1254
1255 static int do_ssh_init(unsigned char c) {
1256 static char vslen;
1257 static char version[10];
1258 static char *vstring;
1259 static int vstrsize;
1260 static char *vlog;
1261 static int i;
1262
1263 crBegin;
1264
1265 /* Search for the string "SSH-" in the input. */
1266 i = 0;
1267 while (1) {
1268 static const int transS[] = { 1, 2, 2, 1 };
1269 static const int transH[] = { 0, 0, 3, 0 };
1270 static const int transminus[] = { 0, 0, 0, -1 };
1271 if (c == 'S') i = transS[i];
1272 else if (c == 'H') i = transH[i];
1273 else if (c == '-') i = transminus[i];
1274 else i = 0;
1275 if (i < 0)
1276 break;
1277 crReturn(1); /* get another character */
1278 }
1279
1280 vstring = smalloc(16);
1281 vstrsize = 16;
1282 strcpy(vstring, "SSH-");
1283 vslen = 4;
1284 i = 0;
1285 while (1) {
1286 crReturn(1); /* get another char */
1287 if (vslen >= vstrsize-1) {
1288 vstrsize += 16;
1289 vstring = srealloc(vstring, vstrsize);
1290 }
1291 vstring[vslen++] = c;
1292 if (i >= 0) {
1293 if (c == '-') {
1294 version[i] = '\0';
1295 i = -1;
1296 } else if (i < sizeof(version)-1)
1297 version[i++] = c;
1298 }
1299 else if (c == '\n')
1300 break;
1301 }
1302
1303 ssh_agentfwd_enabled = FALSE;
1304 rdpkt2_state.incoming_sequence = 0;
1305
1306 vstring[vslen] = 0;
1307 vlog = smalloc(20 + vslen);
1308 sprintf(vlog, "Server version: %s", vstring);
1309 ssh_detect_bugs(vstring);
1310 vlog[strcspn(vlog, "\r\n")] = '\0';
1311 logevent(vlog);
1312 sfree(vlog);
1313
1314 /*
1315 * Server version "1.99" means we can choose whether we use v1
1316 * or v2 protocol. Choice is based on cfg.sshprot.
1317 */
1318 if (ssh_versioncmp(version, cfg.sshprot == 1 ? "2.0" : "1.99") >= 0) {
1319 /*
1320 * This is a v2 server. Begin v2 protocol.
1321 */
1322 char verstring[80], vlog[100];
1323 sprintf(verstring, "SSH-2.0-%s", sshver);
1324 SHA_Init(&exhashbase);
1325 /*
1326 * Hash our version string and their version string.
1327 */
1328 sha_string(&exhashbase, verstring, strlen(verstring));
1329 sha_string(&exhashbase, vstring, strcspn(vstring, "\r\n"));
1330 sprintf(vlog, "We claim version: %s", verstring);
1331 logevent(vlog);
1332 strcat(verstring, "\n");
1333 logevent("Using SSH protocol version 2");
1334 sk_write(s, verstring, strlen(verstring));
1335 ssh_protocol = ssh2_protocol;
1336 ssh_version = 2;
1337 s_rdpkt = ssh2_rdpkt;
1338 } else {
1339 /*
1340 * This is a v1 server. Begin v1 protocol.
1341 */
1342 char verstring[80], vlog[100];
1343 sprintf(verstring, "SSH-%s-%s",
1344 (ssh_versioncmp(version, "1.5") <= 0 ? version : "1.5"),
1345 sshver);
1346 sprintf(vlog, "We claim version: %s", verstring);
1347 logevent(vlog);
1348 strcat(verstring, "\n");
1349 logevent("Using SSH protocol version 1");
1350 sk_write(s, verstring, strlen(verstring));
1351 ssh_protocol = ssh1_protocol;
1352 ssh_version = 1;
1353 s_rdpkt = ssh1_rdpkt;
1354 }
1355 ssh_state = SSH_STATE_BEFORE_SIZE;
1356
1357 sfree(vstring);
1358
1359 crFinish(0);
1360 }
1361
1362 static void ssh_gotdata(unsigned char *data, int datalen)
1363 {
1364 crBegin;
1365
1366 /*
1367 * To begin with, feed the characters one by one to the
1368 * protocol initialisation / selection function do_ssh_init().
1369 * When that returns 0, we're done with the initial greeting
1370 * exchange and can move on to packet discipline.
1371 */
1372 while (1) {
1373 int ret;
1374 if (datalen == 0)
1375 crReturnV; /* more data please */
1376 ret = do_ssh_init(*data);
1377 data++; datalen--;
1378 if (ret == 0)
1379 break;
1380 }
1381
1382 /*
1383 * We emerge from that loop when the initial negotiation is
1384 * over and we have selected an s_rdpkt function. Now pass
1385 * everything to s_rdpkt, and then pass the resulting packets
1386 * to the proper protocol handler.
1387 */
1388 if (datalen == 0)
1389 crReturnV;
1390 while (1) {
1391 while (datalen > 0) {
1392 if ( s_rdpkt(&data, &datalen) == 0 ) {
1393 ssh_protocol(NULL, 0, 1);
1394 if (ssh_state == SSH_STATE_CLOSED) {
1395 return;
1396 }
1397 }
1398 }
1399 crReturnV;
1400 }
1401 crFinishV;
1402 }
1403
1404 static int ssh_closing (Plug plug, char *error_msg, int error_code, int calling_back) {
1405 ssh_state = SSH_STATE_CLOSED;
1406 sk_close(s);
1407 s = NULL;
1408 if (error_msg) {
1409 /* A socket error has occurred. */
1410 connection_fatal (error_msg);
1411 } else {
1412 /* Otherwise, the remote side closed the connection normally. */
1413 }
1414 return 0;
1415 }
1416
1417 static int ssh_receive(Plug plug, int urgent, char *data, int len) {
1418 ssh_gotdata (data, len);
1419 if (ssh_state == SSH_STATE_CLOSED) {
1420 if (s) {
1421 sk_close(s);
1422 s = NULL;
1423 }
1424 return 0;
1425 }
1426 return 1;
1427 }
1428
1429 /*
1430 * Connect to specified host and port.
1431 * Returns an error message, or NULL on success.
1432 * Also places the canonical host name into `realhost'.
1433 */
1434 static char *connect_to_host(char *host, int port, char **realhost)
1435 {
1436 static struct plug_function_table fn_table = {
1437 ssh_closing,
1438 ssh_receive
1439 }, *fn_table_ptr = &fn_table;
1440
1441 SockAddr addr;
1442 char *err;
1443 #ifdef FWHACK
1444 char *FWhost;
1445 int FWport;
1446 #endif
1447
1448 savedhost = smalloc(1+strlen(host));
1449 if (!savedhost)
1450 fatalbox("Out of memory");
1451 strcpy(savedhost, host);
1452
1453 if (port < 0)
1454 port = 22; /* default ssh port */
1455 savedport = port;
1456
1457 #ifdef FWHACK
1458 FWhost = host;
1459 FWport = port;
1460 host = FWSTR;
1461 port = 23;
1462 #endif
1463
1464 /*
1465 * Try to find host.
1466 */
1467 addr = sk_namelookup(host, realhost);
1468 if ( (err = sk_addr_error(addr)) )
1469 return err;
1470
1471 #ifdef FWHACK
1472 *realhost = FWhost;
1473 #endif
1474
1475 /*
1476 * Open socket.
1477 */
1478 s = sk_new(addr, port, 0, 1, &fn_table_ptr);
1479 if ( (err = sk_socket_error(s)) )
1480 return err;
1481
1482 #ifdef FWHACK
1483 sk_write(s, "connect ", 8);
1484 sk_write(s, FWhost, strlen(FWhost));
1485 {
1486 char buf[20];
1487 sprintf(buf, " %d\n", FWport);
1488 sk_write(s, buf, strlen(buf));
1489 }
1490 #endif
1491
1492 return NULL;
1493 }
1494
1495 /*
1496 * Handle the key exchange and user authentication phases.
1497 */
1498 static int do_ssh1_login(unsigned char *in, int inlen, int ispkt)
1499 {
1500 int i, j, len;
1501 unsigned char *rsabuf, *keystr1, *keystr2;
1502 unsigned char cookie[8];
1503 struct RSAKey servkey, hostkey;
1504 struct MD5Context md5c;
1505 static unsigned long supported_ciphers_mask, supported_auths_mask;
1506 static int tried_publickey;
1507 static unsigned char session_id[16];
1508 int cipher_type;
1509 static char username[100];
1510
1511 crBegin;
1512
1513 if (!ispkt) crWaitUntil(ispkt);
1514
1515 if (pktin.type != SSH1_SMSG_PUBLIC_KEY) {
1516 bombout(("Public key packet not received"));
1517 crReturn(0);
1518 }
1519
1520 logevent("Received public keys");
1521
1522 memcpy(cookie, pktin.body, 8);
1523
1524 i = makekey(pktin.body+8, &servkey, &keystr1, 0);
1525 j = makekey(pktin.body+8+i, &hostkey, &keystr2, 0);
1526
1527 /*
1528 * Log the host key fingerprint.
1529 */
1530 {
1531 char logmsg[80];
1532 logevent("Host key fingerprint is:");
1533 strcpy(logmsg, " ");
1534 hostkey.comment = NULL;
1535 rsa_fingerprint(logmsg+strlen(logmsg), sizeof(logmsg)-strlen(logmsg),
1536 &hostkey);
1537 logevent(logmsg);
1538 }
1539
1540 ssh1_remote_protoflags = GET_32BIT(pktin.body+8+i+j);
1541 supported_ciphers_mask = GET_32BIT(pktin.body+12+i+j);
1542 supported_auths_mask = GET_32BIT(pktin.body+16+i+j);
1543
1544 ssh1_local_protoflags = ssh1_remote_protoflags & SSH1_PROTOFLAGS_SUPPORTED;
1545 ssh1_local_protoflags |= SSH1_PROTOFLAG_SCREEN_NUMBER;
1546
1547 MD5Init(&md5c);
1548 MD5Update(&md5c, keystr2, hostkey.bytes);
1549 MD5Update(&md5c, keystr1, servkey.bytes);
1550 MD5Update(&md5c, pktin.body, 8);
1551 MD5Final(session_id, &md5c);
1552
1553 for (i=0; i<32; i++)
1554 session_key[i] = random_byte();
1555
1556 len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes);
1557
1558 rsabuf = smalloc(len);
1559 if (!rsabuf)
1560 fatalbox("Out of memory");
1561
1562 /*
1563 * Verify the host key.
1564 */
1565 {
1566 /*
1567 * First format the key into a string.
1568 */
1569 int len = rsastr_len(&hostkey);
1570 char fingerprint[100];
1571 char *keystr = smalloc(len);
1572 if (!keystr)
1573 fatalbox("Out of memory");
1574 rsastr_fmt(keystr, &hostkey);
1575 rsa_fingerprint(fingerprint, sizeof(fingerprint), &hostkey);
1576 verify_ssh_host_key(savedhost, savedport, "rsa", keystr, fingerprint);
1577 sfree(keystr);
1578 }
1579
1580 for (i=0; i<32; i++) {
1581 rsabuf[i] = session_key[i];
1582 if (i < 16)
1583 rsabuf[i] ^= session_id[i];
1584 }
1585
1586 if (hostkey.bytes > servkey.bytes) {
1587 rsaencrypt(rsabuf, 32, &servkey);
1588 rsaencrypt(rsabuf, servkey.bytes, &hostkey);
1589 } else {
1590 rsaencrypt(rsabuf, 32, &hostkey);
1591 rsaencrypt(rsabuf, hostkey.bytes, &servkey);
1592 }
1593
1594 logevent("Encrypted session key");
1595
1596 switch (cfg.cipher) {
1597 case CIPHER_BLOWFISH: cipher_type = SSH_CIPHER_BLOWFISH; break;
1598 case CIPHER_DES: cipher_type = SSH_CIPHER_DES; break;
1599 case CIPHER_3DES: cipher_type = SSH_CIPHER_3DES; break;
1600 case CIPHER_AES:
1601 c_write_str("AES not supported in SSH1, falling back to 3DES\r\n");
1602 cipher_type = SSH_CIPHER_3DES;
1603 break;
1604 }
1605 if ((supported_ciphers_mask & (1 << cipher_type)) == 0) {
1606 c_write_str("Selected cipher not supported, falling back to 3DES\r\n");
1607 cipher_type = SSH_CIPHER_3DES;
1608 if ((supported_ciphers_mask & (1 << cipher_type)) == 0) {
1609 bombout(("Server violates SSH 1 protocol by "
1610 "not supporting 3DES encryption"));
1611 crReturn(0);
1612 }
1613 }
1614 switch (cipher_type) {
1615 case SSH_CIPHER_3DES: logevent("Using 3DES encryption"); break;
1616 case SSH_CIPHER_DES: logevent("Using single-DES encryption"); break;
1617 case SSH_CIPHER_BLOWFISH: logevent("Using Blowfish encryption"); break;
1618 }
1619
1620 send_packet(SSH1_CMSG_SESSION_KEY,
1621 PKT_CHAR, cipher_type,
1622 PKT_DATA, cookie, 8,
1623 PKT_CHAR, (len*8) >> 8, PKT_CHAR, (len*8) & 0xFF,
1624 PKT_DATA, rsabuf, len,
1625 PKT_INT, ssh1_local_protoflags,
1626 PKT_END);
1627
1628 logevent("Trying to enable encryption...");
1629
1630 sfree(rsabuf);
1631
1632 cipher = cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 :
1633 cipher_type == SSH_CIPHER_DES ? &ssh_des :
1634 &ssh_3des;
1635 cipher->sesskey(session_key);
1636
1637 crWaitUntil(ispkt);
1638
1639 if (pktin.type != SSH1_SMSG_SUCCESS) {
1640 bombout(("Encryption not successfully enabled"));
1641 crReturn(0);
1642 }
1643
1644 logevent("Successfully started encryption");
1645
1646 fflush(stdout);
1647 {
1648 static int pos = 0;
1649 static char c;
1650 if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
1651 if (ssh_get_line) {
1652 if (!ssh_get_line("login as: ",
1653 username, sizeof(username), FALSE)) {
1654 /*
1655 * get_line failed to get a username.
1656 * Terminate.
1657 */
1658 logevent("No username provided. Abandoning session.");
1659 ssh_state = SSH_STATE_CLOSED;
1660 crReturn(1);
1661 }
1662 } else {
1663 c_write_str("login as: ");
1664 ssh_send_ok = 1;
1665 while (pos >= 0) {
1666 crWaitUntil(!ispkt);
1667 while (inlen--) switch (c = *in++) {
1668 case 10: case 13:
1669 username[pos] = 0;
1670 pos = -1;
1671 break;
1672 case 8: case 127:
1673 if (pos > 0) {
1674 c_write_str("\b \b");
1675 pos--;
1676 }
1677 break;
1678 case 21: case 27:
1679 while (pos > 0) {
1680 c_write_str("\b \b");
1681 pos--;
1682 }
1683 break;
1684 case 3: case 4:
1685 random_save_seed();
1686 exit(0);
1687 break;
1688 default:
1689 if (((c >= ' ' && c <= '~') ||
1690 ((unsigned char)c >= 160)) && pos < 40) {
1691 username[pos++] = c;
1692 c_write(&c, 1);
1693 }
1694 break;
1695 }
1696 }
1697 c_write_str("\r\n");
1698 username[strcspn(username, "\n\r")] = '\0';
1699 }
1700 } else {
1701 strncpy(username, cfg.username, 99);
1702 username[99] = '\0';
1703 }
1704
1705 send_packet(SSH1_CMSG_USER, PKT_STR, username, PKT_END);
1706 {
1707 char userlog[22+sizeof(username)];
1708 sprintf(userlog, "Sent username \"%s\"", username);
1709 logevent(userlog);
1710 if (flags & FLAG_INTERACTIVE &&
1711 (!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) {
1712 strcat(userlog, "\r\n");
1713 c_write_str(userlog);
1714 }
1715 }
1716 }
1717
1718 crWaitUntil(ispkt);
1719
1720 tried_publickey = 0;
1721
1722 while (pktin.type == SSH1_SMSG_FAILURE) {
1723 static char password[100];
1724 static char prompt[200];
1725 static int pos;
1726 static char c;
1727 static int pwpkt_type;
1728 /*
1729 * Show password prompt, having first obtained it via a TIS
1730 * or CryptoCard exchange if we're doing TIS or CryptoCard
1731 * authentication.
1732 */
1733 pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
1734 if (agent_exists()) {
1735 /*
1736 * Attempt RSA authentication using Pageant.
1737 */
1738 static unsigned char request[5], *response, *p;
1739 static int responselen;
1740 static int i, nkeys;
1741 static int authed = FALSE;
1742 void *r;
1743
1744 logevent("Pageant is running. Requesting keys.");
1745
1746 /* Request the keys held by the agent. */
1747 PUT_32BIT(request, 1);
1748 request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES;
1749 agent_query(request, 5, &r, &responselen);
1750 response = (unsigned char *)r;
1751 if (response && responselen >= 5 &&
1752 response[4] == SSH1_AGENT_RSA_IDENTITIES_ANSWER) {
1753 p = response + 5;
1754 nkeys = GET_32BIT(p); p += 4;
1755 { char buf[64]; sprintf(buf, "Pageant has %d SSH1 keys", nkeys);
1756 logevent(buf); }
1757 for (i = 0; i < nkeys; i++) {
1758 static struct RSAKey key;
1759 static Bignum challenge;
1760 static char *commentp;
1761 static int commentlen;
1762
1763 { char buf[64]; sprintf(buf, "Trying Pageant key #%d", i);
1764 logevent(buf); }
1765 p += 4;
1766 p += ssh1_read_bignum(p, &key.exponent);
1767 p += ssh1_read_bignum(p, &key.modulus);
1768 commentlen = GET_32BIT(p); p += 4;
1769 commentp = p; p += commentlen;
1770 send_packet(SSH1_CMSG_AUTH_RSA,
1771 PKT_BIGNUM, key.modulus, PKT_END);
1772 crWaitUntil(ispkt);
1773 if (pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
1774 logevent("Key refused");
1775 continue;
1776 }
1777 logevent("Received RSA challenge");
1778 ssh1_read_bignum(pktin.body, &challenge);
1779 {
1780 char *agentreq, *q, *ret;
1781 int len, retlen;
1782 len = 1 + 4; /* message type, bit count */
1783 len += ssh1_bignum_length(key.exponent);
1784 len += ssh1_bignum_length(key.modulus);
1785 len += ssh1_bignum_length(challenge);
1786 len += 16; /* session id */
1787 len += 4; /* response format */
1788 agentreq = smalloc(4 + len);
1789 PUT_32BIT(agentreq, len);
1790 q = agentreq + 4;
1791 *q++ = SSH1_AGENTC_RSA_CHALLENGE;
1792 PUT_32BIT(q, bignum_bitcount(key.modulus));
1793 q += 4;
1794 q += ssh1_write_bignum(q, key.exponent);
1795 q += ssh1_write_bignum(q, key.modulus);
1796 q += ssh1_write_bignum(q, challenge);
1797 memcpy(q, session_id, 16); q += 16;
1798 PUT_32BIT(q, 1); /* response format */
1799 agent_query(agentreq, len+4, &ret, &retlen);
1800 sfree(agentreq);
1801 if (ret) {
1802 if (ret[4] == SSH1_AGENT_RSA_RESPONSE) {
1803 logevent("Sending Pageant's response");
1804 send_packet(SSH1_CMSG_AUTH_RSA_RESPONSE,
1805 PKT_DATA, ret+5, 16, PKT_END);
1806 sfree(ret);
1807 crWaitUntil(ispkt);
1808 if (pktin.type == SSH1_SMSG_SUCCESS) {
1809 logevent("Pageant's response accepted");
1810 if (flags & FLAG_VERBOSE) {
1811 c_write_str("Authenticated using RSA key \"");
1812 c_write(commentp, commentlen);
1813 c_write_str("\" from agent\r\n");
1814 }
1815 authed = TRUE;
1816 } else
1817 logevent("Pageant's response not accepted");
1818 } else {
1819 logevent("Pageant failed to answer challenge");
1820 sfree(ret);
1821 }
1822 } else {
1823 logevent("No reply received from Pageant");
1824 }
1825 }
1826 freebn(key.exponent);
1827 freebn(key.modulus);
1828 freebn(challenge);
1829 if (authed)
1830 break;
1831 }
1832 }
1833 if (authed)
1834 break;
1835 }
1836 if (*cfg.keyfile && !tried_publickey)
1837 pwpkt_type = SSH1_CMSG_AUTH_RSA;
1838
1839 if (pktin.type == SSH1_SMSG_FAILURE &&
1840 cfg.try_tis_auth &&
1841 (supported_auths_mask & (1<<SSH1_AUTH_TIS))) {
1842 pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
1843 logevent("Requested TIS authentication");
1844 send_packet(SSH1_CMSG_AUTH_TIS, PKT_END);
1845 crWaitUntil(ispkt);
1846 if (pktin.type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
1847 logevent("TIS authentication declined");
1848 if (flags & FLAG_INTERACTIVE)
1849 c_write_str("TIS authentication refused.\r\n");
1850 } else {
1851 int challengelen = ((pktin.body[0] << 24) |
1852 (pktin.body[1] << 16) |
1853 (pktin.body[2] << 8) |
1854 (pktin.body[3]));
1855 logevent("Received TIS challenge");
1856 if (challengelen > sizeof(prompt)-1)
1857 challengelen = sizeof(prompt)-1; /* prevent overrun */
1858 memcpy(prompt, pktin.body+4, challengelen);
1859 prompt[challengelen] = '\0';
1860 }
1861 }
1862 if (pktin.type == SSH1_SMSG_FAILURE &&
1863 cfg.try_tis_auth &&
1864 (supported_auths_mask & (1<<SSH1_AUTH_CCARD))) {
1865 pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE;
1866 logevent("Requested CryptoCard authentication");
1867 send_packet(SSH1_CMSG_AUTH_CCARD, PKT_END);
1868 crWaitUntil(ispkt);
1869 if (pktin.type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
1870 logevent("CryptoCard authentication declined");
1871 c_write_str("CryptoCard authentication refused.\r\n");
1872 } else {
1873 int challengelen = ((pktin.body[0] << 24) |
1874 (pktin.body[1] << 16) |
1875 (pktin.body[2] << 8) |
1876 (pktin.body[3]));
1877 logevent("Received CryptoCard challenge");
1878 if (challengelen > sizeof(prompt)-1)
1879 challengelen = sizeof(prompt)-1; /* prevent overrun */
1880 memcpy(prompt, pktin.body+4, challengelen);
1881 strncpy(prompt + challengelen, "\r\nResponse : ",
1882 sizeof(prompt)-challengelen);
1883 prompt[sizeof(prompt)-1] = '\0';
1884 }
1885 }
1886 if (pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
1887 sprintf(prompt, "%.90s@%.90s's password: ",
1888 username, savedhost);
1889 }
1890 if (pwpkt_type == SSH1_CMSG_AUTH_RSA) {
1891 char *comment = NULL;
1892 if (flags & FLAG_VERBOSE)
1893 c_write_str("Trying public key authentication.\r\n");
1894 if (!rsakey_encrypted(cfg.keyfile, &comment)) {
1895 if (flags & FLAG_VERBOSE)
1896 c_write_str("No passphrase required.\r\n");
1897 goto tryauth;
1898 }
1899 sprintf(prompt, "Passphrase for key \"%.100s\": ", comment);
1900 sfree(comment);
1901 }
1902
1903 if (ssh_get_line) {
1904 if (!ssh_get_line(prompt, password, sizeof(password), TRUE)) {
1905 /*
1906 * get_line failed to get a password (for example
1907 * because one was supplied on the command line
1908 * which has already failed to work). Terminate.
1909 */
1910 logevent("No more passwords to try");
1911 ssh_state = SSH_STATE_CLOSED;
1912 crReturn(1);
1913 }
1914 } else {
1915 c_write_str(prompt);
1916 pos = 0;
1917 ssh_send_ok = 1;
1918 while (pos >= 0) {
1919 crWaitUntil(!ispkt);
1920 while (inlen--) switch (c = *in++) {
1921 case 10: case 13:
1922 password[pos] = 0;
1923 pos = -1;
1924 break;
1925 case 8: case 127:
1926 if (pos > 0)
1927 pos--;
1928 break;
1929 case 21: case 27:
1930 pos = 0;
1931 break;
1932 case 3: case 4:
1933 random_save_seed();
1934 exit(0);
1935 break;
1936 default:
1937 if (((c >= ' ' && c <= '~') ||
1938 ((unsigned char)c >= 160)) && pos < sizeof(password))
1939 password[pos++] = c;
1940 break;
1941 }
1942 }
1943 c_write_str("\r\n");
1944 }
1945
1946 tryauth:
1947 if (pwpkt_type == SSH1_CMSG_AUTH_RSA) {
1948 /*
1949 * Try public key authentication with the specified
1950 * key file.
1951 */
1952 static struct RSAKey pubkey;
1953 static Bignum challenge, response;
1954 static int i;
1955 static unsigned char buffer[32];
1956
1957 tried_publickey = 1;
1958 i = loadrsakey(cfg.keyfile, &pubkey, password);
1959 if (i == 0) {
1960 c_write_str("Couldn't load public key from ");
1961 c_write_str(cfg.keyfile);
1962 c_write_str(".\r\n");
1963 continue; /* go and try password */
1964 }
1965 if (i == -1) {
1966 c_write_str("Wrong passphrase.\r\n");
1967 tried_publickey = 0;
1968 continue; /* try again */
1969 }
1970
1971 /*
1972 * Send a public key attempt.
1973 */
1974 send_packet(SSH1_CMSG_AUTH_RSA,
1975 PKT_BIGNUM, pubkey.modulus, PKT_END);
1976
1977 crWaitUntil(ispkt);
1978 if (pktin.type == SSH1_SMSG_FAILURE) {
1979 c_write_str("Server refused our public key.\r\n");
1980 continue; /* go and try password */
1981 }
1982 if (pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
1983 bombout(("Bizarre response to offer of public key"));
1984 crReturn(0);
1985 }
1986 ssh1_read_bignum(pktin.body, &challenge);
1987 response = rsadecrypt(challenge, &pubkey);
1988 freebn(pubkey.private_exponent); /* burn the evidence */
1989
1990 for (i = 0; i < 32; i++) {
1991 buffer[i] = bignum_byte(response, 31-i);
1992 }
1993
1994 MD5Init(&md5c);
1995 MD5Update(&md5c, buffer, 32);
1996 MD5Update(&md5c, session_id, 16);
1997 MD5Final(buffer, &md5c);
1998
1999 send_packet(SSH1_CMSG_AUTH_RSA_RESPONSE,
2000 PKT_DATA, buffer, 16, PKT_END);
2001
2002 crWaitUntil(ispkt);
2003 if (pktin.type == SSH1_SMSG_FAILURE) {
2004 if (flags & FLAG_VERBOSE)
2005 c_write_str("Failed to authenticate with our public key.\r\n");
2006 continue; /* go and try password */
2007 } else if (pktin.type != SSH1_SMSG_SUCCESS) {
2008 bombout(("Bizarre response to RSA authentication response"));
2009 crReturn(0);
2010 }
2011
2012 break; /* we're through! */
2013 } else {
2014 if (pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
2015 /*
2016 * Defence against traffic analysis: we send a
2017 * whole bunch of packets containing strings of
2018 * different lengths. One of these strings is the
2019 * password, in a SSH1_CMSG_AUTH_PASSWORD packet.
2020 * The others are all random data in
2021 * SSH1_MSG_IGNORE packets. This way a passive
2022 * listener can't tell which is the password, and
2023 * hence can't deduce the password length.
2024 *
2025 * Anybody with a password length greater than 16
2026 * bytes is going to have enough entropy in their
2027 * password that a listener won't find it _that_
2028 * much help to know how long it is. So what we'll
2029 * do is:
2030 *
2031 * - if password length < 16, we send 15 packets
2032 * containing string lengths 1 through 15
2033 *
2034 * - otherwise, we let N be the nearest multiple
2035 * of 8 below the password length, and send 8
2036 * packets containing string lengths N through
2037 * N+7. This won't obscure the order of
2038 * magnitude of the password length, but it will
2039 * introduce a bit of extra uncertainty.
2040 *
2041 * A few servers (the old 1.2.18 through 1.2.22)
2042 * can't deal with SSH1_MSG_IGNORE. For these
2043 * servers, we need an alternative defence. We make
2044 * use of the fact that the password is interpreted
2045 * as a C string: so we can append a NUL, then some
2046 * random data.
2047 */
2048 if (ssh_remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE) {
2049 char string[64];
2050 char *s;
2051 int len;
2052
2053 len = strlen(password);
2054 if (len < sizeof(string)) {
2055 s = string;
2056 strcpy(string, password);
2057 len++; /* cover the zero byte */
2058 while (len < sizeof(string)) {
2059 string[len++] = (char)random_byte();
2060 }
2061 } else {
2062 s = password;
2063 }
2064 send_packet(pwpkt_type, PKT_INT, len,
2065 PKT_DATA, s, len, PKT_END);
2066 } else {
2067 int bottom, top, pwlen, i;
2068 char *randomstr;
2069
2070 pwlen = strlen(password);
2071 if (pwlen < 16) {
2072 bottom = 0; /* zero length passwords are OK! :-) */
2073 top = 15;
2074 } else {
2075 bottom = pwlen &~ 7;
2076 top = bottom + 7;
2077 }
2078
2079 assert(pwlen >= bottom && pwlen <= top);
2080
2081 randomstr = smalloc(top+1);
2082
2083 for (i = bottom; i <= top; i++) {
2084 if (i == pwlen)
2085 defer_packet(pwpkt_type, PKT_STR, password, PKT_END);
2086 else {
2087 for (j = 0; j < i; j++) {
2088 do {
2089 randomstr[j] = random_byte();
2090 } while (randomstr[j] == '\0');
2091 }
2092 randomstr[i] = '\0';
2093 defer_packet(SSH1_MSG_IGNORE,
2094 PKT_STR, randomstr, PKT_END);
2095 }
2096 }
2097 ssh_pkt_defersend();
2098 }
2099 } else {
2100 send_packet(pwpkt_type, PKT_STR, password, PKT_END);
2101 }
2102 }
2103 logevent("Sent password");
2104 memset(password, 0, strlen(password));
2105 crWaitUntil(ispkt);
2106 if (pktin.type == SSH1_SMSG_FAILURE) {
2107 if (flags & FLAG_VERBOSE)
2108 c_write_str("Access denied\r\n");
2109 logevent("Authentication refused");
2110 } else if (pktin.type == SSH1_MSG_DISCONNECT) {
2111 logevent("Received disconnect request");
2112 ssh_state = SSH_STATE_CLOSED;
2113 crReturn(1);
2114 } else if (pktin.type != SSH1_SMSG_SUCCESS) {
2115 bombout(("Strange packet received, type %d", pktin.type));
2116 crReturn(0);
2117 }
2118 }
2119
2120 logevent("Authentication successful");
2121
2122 crFinish(1);
2123 }
2124
2125 void sshfwd_close(struct ssh_channel *c) {
2126 if (c && !c->closes) {
2127 if (ssh_version == 1) {
2128 send_packet(SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid, PKT_END);
2129 } else {
2130 ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE);
2131 ssh2_pkt_adduint32(c->remoteid);
2132 ssh2_pkt_send();
2133 }
2134 c->closes = 1;
2135 if (c->type == CHAN_X11) {
2136 c->u.x11.s = NULL;
2137 logevent("X11 connection terminated");
2138 }
2139 }
2140 }
2141
2142 void sshfwd_write(struct ssh_channel *c, char *buf, int len) {
2143 if (ssh_version == 1) {
2144 send_packet(SSH1_MSG_CHANNEL_DATA,
2145 PKT_INT, c->remoteid,
2146 PKT_INT, len,
2147 PKT_DATA, buf, len,
2148 PKT_END);
2149 } else {
2150 ssh2_add_channel_data(c, buf, len);
2151 ssh2_try_send(c);
2152 }
2153 }
2154
2155 static void ssh1_protocol(unsigned char *in, int inlen, int ispkt) {
2156 crBegin;
2157
2158 random_init();
2159
2160 while (!do_ssh1_login(in, inlen, ispkt)) {
2161 crReturnV;
2162 }
2163 if (ssh_state == SSH_STATE_CLOSED)
2164 crReturnV;
2165
2166 if (cfg.agentfwd && agent_exists()) {
2167 logevent("Requesting agent forwarding");
2168 send_packet(SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END);
2169 do { crReturnV; } while (!ispkt);
2170 if (pktin.type != SSH1_SMSG_SUCCESS && pktin.type != SSH1_SMSG_FAILURE) {
2171 bombout(("Protocol confusion"));
2172 crReturnV;
2173 } else if (pktin.type == SSH1_SMSG_FAILURE) {
2174 logevent("Agent forwarding refused");
2175 } else {
2176 logevent("Agent forwarding enabled");
2177 ssh_agentfwd_enabled = TRUE;
2178 }
2179 }
2180
2181 if (cfg.x11_forward) {
2182 char proto[20], data[64];
2183 logevent("Requesting X11 forwarding");
2184 x11_invent_auth(proto, sizeof(proto), data, sizeof(data));
2185 if (ssh1_local_protoflags & SSH1_PROTOFLAG_SCREEN_NUMBER) {
2186 send_packet(SSH1_CMSG_X11_REQUEST_FORWARDING,
2187 PKT_STR, proto, PKT_STR, data,
2188 PKT_INT, 0,
2189 PKT_END);
2190 } else {
2191 send_packet(SSH1_CMSG_X11_REQUEST_FORWARDING,
2192 PKT_STR, proto, PKT_STR, data,
2193 PKT_END);
2194 }
2195 do { crReturnV; } while (!ispkt);
2196 if (pktin.type != SSH1_SMSG_SUCCESS && pktin.type != SSH1_SMSG_FAILURE) {
2197 bombout(("Protocol confusion"));
2198 crReturnV;
2199 } else if (pktin.type == SSH1_SMSG_FAILURE) {
2200 logevent("X11 forwarding refused");
2201 } else {
2202 logevent("X11 forwarding enabled");
2203 ssh_X11_fwd_enabled = TRUE;
2204 }
2205 }
2206
2207 if (!cfg.nopty) {
2208 send_packet(SSH1_CMSG_REQUEST_PTY,
2209 PKT_STR, cfg.termtype,
2210 PKT_INT, rows, PKT_INT, cols,
2211 PKT_INT, 0, PKT_INT, 0,
2212 PKT_CHAR, 0,
2213 PKT_END);
2214 ssh_state = SSH_STATE_INTERMED;
2215 do { crReturnV; } while (!ispkt);
2216 if (pktin.type != SSH1_SMSG_SUCCESS && pktin.type != SSH1_SMSG_FAILURE) {
2217 bombout(("Protocol confusion"));
2218 crReturnV;
2219 } else if (pktin.type == SSH1_SMSG_FAILURE) {
2220 c_write_str("Server refused to allocate pty\r\n");
2221 ssh_editing = ssh_echoing = 1;
2222 }
2223 logevent("Allocated pty");
2224 } else {
2225 ssh_editing = ssh_echoing = 1;
2226 }
2227
2228 if (cfg.compression) {
2229 send_packet(SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END);
2230 do { crReturnV; } while (!ispkt);
2231 if (pktin.type != SSH1_SMSG_SUCCESS && pktin.type != SSH1_SMSG_FAILURE) {
2232 bombout(("Protocol confusion"));
2233 crReturnV;
2234 } else if (pktin.type == SSH1_SMSG_FAILURE) {
2235 c_write_str("Server refused to compress\r\n");
2236 }
2237 logevent("Started compression");
2238 ssh1_compressing = TRUE;
2239 zlib_compress_init();
2240 zlib_decompress_init();
2241 }
2242
2243 if (*cfg.remote_cmd_ptr)
2244 send_packet(SSH1_CMSG_EXEC_CMD, PKT_STR, cfg.remote_cmd_ptr, PKT_END);
2245 else
2246 send_packet(SSH1_CMSG_EXEC_SHELL, PKT_END);
2247 logevent("Started session");
2248
2249 ssh_state = SSH_STATE_SESSION;
2250 if (size_needed)
2251 ssh_size();
2252 if (eof_needed)
2253 ssh_special(TS_EOF);
2254
2255 ldisc_send(NULL, 0); /* cause ldisc to notice changes */
2256 ssh_send_ok = 1;
2257 ssh_channels = newtree234(ssh_channelcmp);
2258 while (1) {
2259 crReturnV;
2260 if (ispkt) {
2261 if (pktin.type == SSH1_SMSG_STDOUT_DATA ||
2262 pktin.type == SSH1_SMSG_STDERR_DATA) {
2263 long len = GET_32BIT(pktin.body);
2264 from_backend(pktin.type == SSH1_SMSG_STDERR_DATA,
2265 pktin.body+4, len);
2266 } else if (pktin.type == SSH1_MSG_DISCONNECT) {
2267 ssh_state = SSH_STATE_CLOSED;
2268 logevent("Received disconnect request");
2269 crReturnV;
2270 } else if (pktin.type == SSH1_SMSG_X11_OPEN) {
2271 /* Remote side is trying to open a channel to talk to our
2272 * X-Server. Give them back a local channel number. */
2273 struct ssh_channel *c;
2274
2275 logevent("Received X11 connect request");
2276 /* Refuse if X11 forwarding is disabled. */
2277 if (!ssh_X11_fwd_enabled) {
2278 send_packet(SSH1_MSG_CHANNEL_OPEN_FAILURE,
2279 PKT_INT, GET_32BIT(pktin.body),
2280 PKT_END);
2281 logevent("Rejected X11 connect request");
2282 } else {
2283 c = smalloc(sizeof(struct ssh_channel));
2284
2285 if ( x11_init(&c->u.x11.s, cfg.x11_display, c) != NULL ) {
2286 logevent("opening X11 forward connection failed");
2287 sfree(c);
2288 send_packet(SSH1_MSG_CHANNEL_OPEN_FAILURE,
2289 PKT_INT, GET_32BIT(pktin.body),
2290 PKT_END);
2291 } else {
2292 logevent("opening X11 forward connection succeeded");
2293 c->remoteid = GET_32BIT(pktin.body);
2294 c->localid = alloc_channel_id();
2295 c->closes = 0;
2296 c->type = CHAN_X11; /* identify channel type */
2297 add234(ssh_channels, c);
2298 send_packet(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
2299 PKT_INT, c->remoteid, PKT_INT, c->localid,
2300 PKT_END);
2301 logevent("Opened X11 forward channel");
2302 }
2303 }
2304 } else if (pktin.type == SSH1_SMSG_AGENT_OPEN) {
2305 /* Remote side is trying to open a channel to talk to our
2306 * agent. Give them back a local channel number. */
2307 struct ssh_channel *c;
2308
2309 /* Refuse if agent forwarding is disabled. */
2310 if (!ssh_agentfwd_enabled) {
2311 send_packet(SSH1_MSG_CHANNEL_OPEN_FAILURE,
2312 PKT_INT, GET_32BIT(pktin.body),
2313 PKT_END);
2314 } else {
2315 c = smalloc(sizeof(struct ssh_channel));
2316 c->remoteid = GET_32BIT(pktin.body);
2317 c->localid = alloc_channel_id();
2318 c->closes = 0;
2319 c->type = CHAN_AGENT; /* identify channel type */
2320 c->u.a.lensofar = 0;
2321 add234(ssh_channels, c);
2322 send_packet(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
2323 PKT_INT, c->remoteid, PKT_INT, c->localid,
2324 PKT_END);
2325 }
2326 } else if (pktin.type == SSH1_MSG_CHANNEL_CLOSE ||
2327 pktin.type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION) {
2328 /* Remote side closes a channel. */
2329 unsigned i = GET_32BIT(pktin.body);
2330 struct ssh_channel *c;
2331 c = find234(ssh_channels, &i, ssh_channelfind);
2332 if (c) {
2333 int closetype;
2334 closetype = (pktin.type == SSH1_MSG_CHANNEL_CLOSE ? 1 : 2);
2335 if (!(c->closes & closetype))
2336 send_packet(pktin.type, PKT_INT, c->remoteid, PKT_END);
2337 if ((c->closes == 0) && (c->type == CHAN_X11)) {
2338 logevent("X11 connection closed");
2339 assert(c->u.x11.s != NULL);
2340 x11_close(c->u.x11.s);
2341 c->u.x11.s = NULL;
2342 }
2343 c->closes |= closetype;
2344 if (c->closes == 3) {
2345 del234(ssh_channels, c);
2346 sfree(c);
2347 }
2348 }
2349 } else if (pktin.type == SSH1_MSG_CHANNEL_DATA) {
2350 /* Data sent down one of our channels. */
2351 int i = GET_32BIT(pktin.body);
2352 int len = GET_32BIT(pktin.body+4);
2353 unsigned char *p = pktin.body+8;
2354 struct ssh_channel *c;
2355 c = find234(ssh_channels, &i, ssh_channelfind);
2356 if (c) {
2357 switch(c->type) {
2358 case CHAN_X11:
2359 x11_send(c->u.x11.s, p, len);
2360 break;
2361 case CHAN_AGENT:
2362 /* Data for an agent message. Buffer it. */
2363 while (len > 0) {
2364 if (c->u.a.lensofar < 4) {
2365 int l = min(4 - c->u.a.lensofar, len);
2366 memcpy(c->u.a.msglen + c->u.a.lensofar, p, l);
2367 p += l; len -= l; c->u.a.lensofar += l;
2368 }
2369 if (c->u.a.lensofar == 4) {
2370 c->u.a.totallen = 4 + GET_32BIT(c->u.a.msglen);
2371 c->u.a.message = smalloc(c->u.a.totallen);
2372 memcpy(c->u.a.message, c->u.a.msglen, 4);
2373 }
2374 if (c->u.a.lensofar >= 4 && len > 0) {
2375 int l = min(c->u.a.totallen - c->u.a.lensofar, len);
2376 memcpy(c->u.a.message + c->u.a.lensofar, p, l);
2377 p += l; len -= l; c->u.a.lensofar += l;
2378 }
2379 if (c->u.a.lensofar == c->u.a.totallen) {
2380 void *reply, *sentreply;
2381 int replylen;
2382 agent_query(c->u.a.message, c->u.a.totallen,
2383 &reply, &replylen);
2384 if (reply)
2385 sentreply = reply;
2386 else {
2387 /* Fake SSH_AGENT_FAILURE. */
2388 sentreply = "\0\0\0\1\5";
2389 replylen = 5;
2390 }
2391 send_packet(SSH1_MSG_CHANNEL_DATA,
2392 PKT_INT, c->remoteid,
2393 PKT_INT, replylen,
2394 PKT_DATA, sentreply, replylen,
2395 PKT_END);
2396 if (reply)
2397 sfree(reply);
2398 sfree(c->u.a.message);
2399 c->u.a.lensofar = 0;
2400 }
2401 }
2402 break;
2403 }
2404 }
2405 } else if (pktin.type == SSH1_SMSG_SUCCESS) {
2406 /* may be from EXEC_SHELL on some servers */
2407 } else if (pktin.type == SSH1_SMSG_FAILURE) {
2408 /* may be from EXEC_SHELL on some servers
2409 * if no pty is available or in other odd cases. Ignore */
2410 } else if (pktin.type == SSH1_SMSG_EXIT_STATUS) {
2411 send_packet(SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
2412 } else {
2413 bombout(("Strange packet received: type %d", pktin.type));
2414 crReturnV;
2415 }
2416 } else {
2417 while (inlen > 0) {
2418 int len = min(inlen, 512);
2419 send_packet(SSH1_CMSG_STDIN_DATA,
2420 PKT_INT, len, PKT_DATA, in, len, PKT_END);
2421 in += len;
2422 inlen -= len;
2423 }
2424 }
2425 }
2426
2427 crFinishV;
2428 }
2429
2430 /*
2431 * Utility routine for decoding comma-separated strings in KEXINIT.
2432 */
2433 static int in_commasep_string(char *needle, char *haystack, int haylen) {
2434 int needlen = strlen(needle);
2435 while (1) {
2436 /*
2437 * Is it at the start of the string?
2438 */
2439 if (haylen >= needlen && /* haystack is long enough */
2440 !memcmp(needle, haystack, needlen) && /* initial match */
2441 (haylen == needlen || haystack[needlen] == ',')
2442 /* either , or EOS follows */
2443 )
2444 return 1;
2445 /*
2446 * If not, search for the next comma and resume after that.
2447 * If no comma found, terminate.
2448 */
2449 while (haylen > 0 && *haystack != ',')
2450 haylen--, haystack++;
2451 if (haylen == 0)
2452 return 0;
2453 haylen--, haystack++; /* skip over comma itself */
2454 }
2455 }
2456
2457 /*
2458 * SSH2 key creation method.
2459 */
2460 static void ssh2_mkkey(Bignum K, char *H, char *sessid, char chr, char *keyspace) {
2461 SHA_State s;
2462 /* First 20 bytes. */
2463 SHA_Init(&s);
2464 sha_mpint(&s, K);
2465 SHA_Bytes(&s, H, 20);
2466 SHA_Bytes(&s, &chr, 1);
2467 SHA_Bytes(&s, sessid, 20);
2468 SHA_Final(&s, keyspace);
2469 /* Next 20 bytes. */
2470 SHA_Init(&s);
2471 sha_mpint(&s, K);
2472 SHA_Bytes(&s, H, 20);
2473 SHA_Bytes(&s, keyspace, 20);
2474 SHA_Final(&s, keyspace+20);
2475 }
2476
2477 /*
2478 * Handle the SSH2 transport layer.
2479 */
2480 static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt)
2481 {
2482 static int i, j, len, nbits, pbits;
2483 static char *str;
2484 static Bignum p, g, e, f, K;
2485 static int kex_init_value, kex_reply_value;
2486 static const struct ssh_mac **maclist;
2487 static int nmacs;
2488 static const struct ssh2_cipher *cscipher_tobe = NULL;
2489 static const struct ssh2_cipher *sccipher_tobe = NULL;
2490 static const struct ssh_mac *csmac_tobe = NULL;
2491 static const struct ssh_mac *scmac_tobe = NULL;
2492 static const struct ssh_compress *cscomp_tobe = NULL;
2493 static const struct ssh_compress *sccomp_tobe = NULL;
2494 static char *hostkeydata, *sigdata, *keystr, *fingerprint;
2495 static int hostkeylen, siglen;
2496 static void *hkey; /* actual host key */
2497 static unsigned char exchange_hash[20];
2498 static unsigned char keyspace[40];
2499 static const struct ssh2_ciphers *preferred_cipher;
2500 static const struct ssh_compress *preferred_comp;
2501 static int first_kex;
2502
2503 crBegin;
2504 random_init();
2505 first_kex = 1;
2506
2507 /*
2508 * Set up the preferred cipher and compression.
2509 */
2510 if (cfg.cipher == CIPHER_BLOWFISH) {
2511 preferred_cipher = &ssh2_blowfish;
2512 } else if (cfg.cipher == CIPHER_DES) {
2513 logevent("Single DES not supported in SSH2; using 3DES");
2514 preferred_cipher = &ssh2_3des;
2515 } else if (cfg.cipher == CIPHER_3DES) {
2516 preferred_cipher = &ssh2_3des;
2517 } else if (cfg.cipher == CIPHER_AES) {
2518 preferred_cipher = &ssh2_aes;
2519 } else {
2520 /* Shouldn't happen, but we do want to initialise to _something_. */
2521 preferred_cipher = &ssh2_3des;
2522 }
2523 if (cfg.compression)
2524 preferred_comp = &ssh_zlib;
2525 else
2526 preferred_comp = &ssh_comp_none;
2527
2528 /*
2529 * Be prepared to work around the buggy MAC problem.
2530 */
2531 if (cfg.buggymac || (ssh_remote_bugs & BUG_SSH2_HMAC))
2532 maclist = buggymacs, nmacs = lenof(buggymacs);
2533 else
2534 maclist = macs, nmacs = lenof(macs);
2535
2536 begin_key_exchange:
2537 /*
2538 * Construct and send our key exchange packet.
2539 */
2540 ssh2_pkt_init(SSH2_MSG_KEXINIT);
2541 for (i = 0; i < 16; i++)
2542 ssh2_pkt_addbyte((unsigned char)random_byte());
2543 /* List key exchange algorithms. */
2544 ssh2_pkt_addstring_start();
2545 for (i = 0; i < lenof(kex_algs); i++) {
2546 ssh2_pkt_addstring_str(kex_algs[i]->name);
2547 if (i < lenof(kex_algs)-1)
2548 ssh2_pkt_addstring_str(",");
2549 }
2550 /* List server host key algorithms. */
2551 ssh2_pkt_addstring_start();
2552 for (i = 0; i < lenof(hostkey_algs); i++) {
2553 ssh2_pkt_addstring_str(hostkey_algs[i]->name);
2554 if (i < lenof(hostkey_algs)-1)
2555 ssh2_pkt_addstring_str(",");
2556 }
2557 /* List client->server encryption algorithms. */
2558 ssh2_pkt_addstring_start();
2559 for (i = 0; i < lenof(ciphers)+1; i++) {
2560 const struct ssh2_ciphers *c = i==0 ? preferred_cipher : ciphers[i-1];
2561 for (j = 0; j < c->nciphers; j++) {
2562 ssh2_pkt_addstring_str(c->list[j]->name);
2563 if (i < lenof(ciphers) || j < c->nciphers-1)
2564 ssh2_pkt_addstring_str(",");
2565 }
2566 }
2567 /* List server->client encryption algorithms. */
2568 ssh2_pkt_addstring_start();
2569 for (i = 0; i < lenof(ciphers)+1; i++) {
2570 const struct ssh2_ciphers *c = i==0 ? preferred_cipher : ciphers[i-1];
2571 for (j = 0; j < c->nciphers; j++) {
2572 ssh2_pkt_addstring_str(c->list[j]->name);
2573 if (i < lenof(ciphers) || j < c->nciphers-1)
2574 ssh2_pkt_addstring_str(",");
2575 }
2576 }
2577 /* List client->server MAC algorithms. */
2578 ssh2_pkt_addstring_start();
2579 for (i = 0; i < nmacs; i++) {
2580 ssh2_pkt_addstring_str(maclist[i]->name);
2581 if (i < nmacs-1)
2582 ssh2_pkt_addstring_str(",");
2583 }
2584 /* List server->client MAC algorithms. */
2585 ssh2_pkt_addstring_start();
2586 for (i = 0; i < nmacs; i++) {
2587 ssh2_pkt_addstring_str(maclist[i]->name);
2588 if (i < nmacs-1)
2589 ssh2_pkt_addstring_str(",");
2590 }
2591 /* List client->server compression algorithms. */
2592 ssh2_pkt_addstring_start();
2593 for (i = 0; i < lenof(compressions)+1; i++) {
2594 const struct ssh_compress *c = i==0 ? preferred_comp : compressions[i-1];
2595 ssh2_pkt_addstring_str(c->name);
2596 if (i < lenof(compressions))
2597 ssh2_pkt_addstring_str(",");
2598 }
2599 /* List server->client compression algorithms. */
2600 ssh2_pkt_addstring_start();
2601 for (i = 0; i < lenof(compressions)+1; i++) {
2602 const struct ssh_compress *c = i==0 ? preferred_comp : compressions[i-1];
2603 ssh2_pkt_addstring_str(c->name);
2604 if (i < lenof(compressions))
2605 ssh2_pkt_addstring_str(",");
2606 }
2607 /* List client->server languages. Empty list. */
2608 ssh2_pkt_addstring_start();
2609 /* List server->client languages. Empty list. */
2610 ssh2_pkt_addstring_start();
2611 /* First KEX packet does _not_ follow, because we're not that brave. */
2612 ssh2_pkt_addbool(FALSE);
2613 /* Reserved. */
2614 ssh2_pkt_adduint32(0);
2615
2616 exhash = exhashbase;
2617 sha_string(&exhash, pktout.data+5, pktout.length-5);
2618
2619 ssh2_pkt_send();
2620
2621 if (!ispkt) crWaitUntil(ispkt);
2622 sha_string(&exhash, pktin.data+5, pktin.length-5);
2623
2624 /*
2625 * Now examine the other side's KEXINIT to see what we're up
2626 * to.
2627 */
2628 if (pktin.type != SSH2_MSG_KEXINIT) {
2629 bombout(("expected key exchange packet from server"));
2630 crReturn(0);
2631 }
2632 kex = NULL; hostkey = NULL; cscipher_tobe = NULL; sccipher_tobe = NULL;
2633 csmac_tobe = NULL; scmac_tobe = NULL; cscomp_tobe = NULL; sccomp_tobe = NULL;
2634 pktin.savedpos += 16; /* skip garbage cookie */
2635 ssh2_pkt_getstring(&str, &len); /* key exchange algorithms */
2636 for (i = 0; i < lenof(kex_algs); i++) {
2637 if (in_commasep_string(kex_algs[i]->name, str, len)) {
2638 kex = kex_algs[i];
2639 break;
2640 }
2641 }
2642 ssh2_pkt_getstring(&str, &len); /* host key algorithms */
2643 for (i = 0; i < lenof(hostkey_algs); i++) {
2644 if (in_commasep_string(hostkey_algs[i]->name, str, len)) {
2645 hostkey = hostkey_algs[i];
2646 break;
2647 }
2648 }
2649 ssh2_pkt_getstring(&str, &len); /* client->server cipher */
2650 for (i = 0; i < lenof(ciphers)+1; i++) {
2651 const struct ssh2_ciphers *c = i==0 ? preferred_cipher : ciphers[i-1];
2652 for (j = 0; j < c->nciphers; j++) {
2653 if (in_commasep_string(c->list[j]->name, str, len)) {
2654 cscipher_tobe = c->list[j];
2655 break;
2656 }
2657 }
2658 if (cscipher_tobe)
2659 break;
2660 }
2661 ssh2_pkt_getstring(&str, &len); /* server->client cipher */
2662 for (i = 0; i < lenof(ciphers)+1; i++) {
2663 const struct ssh2_ciphers *c = i==0 ? preferred_cipher : ciphers[i-1];
2664 for (j = 0; j < c->nciphers; j++) {
2665 if (in_commasep_string(c->list[j]->name, str, len)) {
2666 sccipher_tobe = c->list[j];
2667 break;
2668 }
2669 }
2670 if (sccipher_tobe)
2671 break;
2672 }
2673 ssh2_pkt_getstring(&str, &len); /* client->server mac */
2674 for (i = 0; i < nmacs; i++) {
2675 if (in_commasep_string(maclist[i]->name, str, len)) {
2676 csmac_tobe = maclist[i];
2677 break;
2678 }
2679 }
2680 ssh2_pkt_getstring(&str, &len); /* server->client mac */
2681 for (i = 0; i < nmacs; i++) {
2682 if (in_commasep_string(maclist[i]->name, str, len)) {
2683 scmac_tobe = maclist[i];
2684 break;
2685 }
2686 }
2687 ssh2_pkt_getstring(&str, &len); /* client->server compression */
2688 for (i = 0; i < lenof(compressions)+1; i++) {
2689 const struct ssh_compress *c = i==0 ? preferred_comp : compressions[i-1];
2690 if (in_commasep_string(c->name, str, len)) {
2691 cscomp_tobe = c;
2692 break;
2693 }
2694 }
2695 ssh2_pkt_getstring(&str, &len); /* server->client compression */
2696 for (i = 0; i < lenof(compressions)+1; i++) {
2697 const struct ssh_compress *c = i==0 ? preferred_comp : compressions[i-1];
2698 if (in_commasep_string(c->name, str, len)) {
2699 sccomp_tobe = c;
2700 break;
2701 }
2702 }
2703
2704 /*
2705 * Work out the number of bits of key we will need from the key
2706 * exchange. We start with the maximum key length of either
2707 * cipher...
2708 */
2709 {
2710 int csbits, scbits;
2711
2712 csbits = cscipher_tobe->keylen;
2713 scbits = sccipher_tobe->keylen;
2714 nbits = (csbits > scbits ? csbits : scbits);
2715 }
2716 /* The keys only have 160-bit entropy, since they're based on
2717 * a SHA-1 hash. So cap the key size at 160 bits. */
2718 if (nbits > 160) nbits = 160;
2719
2720 /*
2721 * If we're doing Diffie-Hellman group exchange, start by
2722 * requesting a group.
2723 */
2724 if (kex == &ssh_diffiehellman_gex) {
2725 logevent("Doing Diffie-Hellman group exchange");
2726 /*
2727 * Work out how big a DH group we will need to allow that
2728 * much data.
2729 */
2730 pbits = 512 << ((nbits-1) / 64);
2731 ssh2_pkt_init(SSH2_MSG_KEX_DH_GEX_REQUEST);
2732 ssh2_pkt_adduint32(pbits);
2733 ssh2_pkt_send();
2734
2735 crWaitUntil(ispkt);
2736 if (pktin.type != SSH2_MSG_KEX_DH_GEX_GROUP) {
2737 bombout(("expected key exchange group packet from server"));
2738 crReturn(0);
2739 }
2740 p = ssh2_pkt_getmp();
2741 g = ssh2_pkt_getmp();
2742 dh_setup_group(p, g);
2743 kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT;
2744 kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY;
2745 } else {
2746 dh_setup_group1();
2747 kex_init_value = SSH2_MSG_KEXDH_INIT;
2748 kex_reply_value = SSH2_MSG_KEXDH_REPLY;
2749 }
2750
2751 logevent("Doing Diffie-Hellman key exchange");
2752 /*
2753 * Now generate and send e for Diffie-Hellman.
2754 */
2755 e = dh_create_e(nbits*2);
2756 ssh2_pkt_init(kex_init_value);
2757 ssh2_pkt_addmp(e);
2758 ssh2_pkt_send();
2759
2760 crWaitUntil(ispkt);
2761 if (pktin.type != kex_reply_value) {
2762 bombout(("expected key exchange reply packet from server"));
2763 crReturn(0);
2764 }
2765 ssh2_pkt_getstring(&hostkeydata, &hostkeylen);
2766 f = ssh2_pkt_getmp();
2767 ssh2_pkt_getstring(&sigdata, &siglen);
2768
2769 K = dh_find_K(f);
2770
2771 sha_string(&exhash, hostkeydata, hostkeylen);
2772 if (kex == &ssh_diffiehellman_gex) {
2773 sha_uint32(&exhash, pbits);
2774 sha_mpint(&exhash, p);
2775 sha_mpint(&exhash, g);
2776 }
2777 sha_mpint(&exhash, e);
2778 sha_mpint(&exhash, f);
2779 sha_mpint(&exhash, K);
2780 SHA_Final(&exhash, exchange_hash);
2781
2782 dh_cleanup();
2783
2784 #if 0
2785 debug(("Exchange hash is:\r\n"));
2786 for (i = 0; i < 20; i++)
2787 debug((" %02x", exchange_hash[i]));
2788 debug(("\r\n"));
2789 #endif
2790
2791 hkey = hostkey->newkey(hostkeydata, hostkeylen);
2792 if (!hostkey->verifysig(hkey, sigdata, siglen, exchange_hash, 20)) {
2793 bombout(("Server failed host key check"));
2794 crReturn(0);
2795 }
2796
2797 /*
2798 * Expect SSH2_MSG_NEWKEYS from server.
2799 */
2800 crWaitUntil(ispkt);
2801 if (pktin.type != SSH2_MSG_NEWKEYS) {
2802 bombout(("expected new-keys packet from server"));
2803 crReturn(0);
2804 }
2805
2806 /*
2807 * Authenticate remote host: verify host key. (We've already
2808 * checked the signature of the exchange hash.)
2809 */
2810 keystr = hostkey->fmtkey(hkey);
2811 fingerprint = hostkey->fingerprint(hkey);
2812 verify_ssh_host_key(savedhost, savedport, hostkey->keytype,
2813 keystr, fingerprint);
2814 if (first_kex) { /* don't bother logging this in rekeys */
2815 logevent("Host key fingerprint is:");
2816 logevent(fingerprint);
2817 }
2818 sfree(fingerprint);
2819 sfree(keystr);
2820 hostkey->freekey(hkey);
2821
2822 /*
2823 * Send SSH2_MSG_NEWKEYS.
2824 */
2825 ssh2_pkt_init(SSH2_MSG_NEWKEYS);
2826 ssh2_pkt_send();
2827
2828 /*
2829 * Create and initialise session keys.
2830 */
2831 cscipher = cscipher_tobe;
2832 sccipher = sccipher_tobe;
2833 csmac = csmac_tobe;
2834 scmac = scmac_tobe;
2835 cscomp = cscomp_tobe;
2836 sccomp = sccomp_tobe;
2837 cscomp->compress_init();
2838 sccomp->decompress_init();
2839 /*
2840 * Set IVs after keys. Here we use the exchange hash from the
2841 * _first_ key exchange.
2842 */
2843 if (first_kex)
2844 memcpy(ssh2_session_id, exchange_hash, sizeof(exchange_hash));
2845 ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'C', keyspace);
2846 cscipher->setcskey(keyspace);
2847 ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'D', keyspace);
2848 sccipher->setsckey(keyspace);
2849 ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'A', keyspace);
2850 cscipher->setcsiv(keyspace);
2851 ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'B', keyspace);
2852 sccipher->setsciv(keyspace);
2853 ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'E', keyspace);
2854 csmac->setcskey(keyspace);
2855 ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'F', keyspace);
2856 scmac->setsckey(keyspace);
2857
2858 /*
2859 * If this is the first key exchange phase, we must pass the
2860 * SSH2_MSG_NEWKEYS packet to the next layer, not because it
2861 * wants to see it but because it will need time to initialise
2862 * itself before it sees an actual packet. In subsequent key
2863 * exchange phases, we don't pass SSH2_MSG_NEWKEYS on, because
2864 * it would only confuse the layer above.
2865 */
2866 if (!first_kex) {
2867 crReturn(0);
2868 }
2869 first_kex = 0;
2870
2871 /*
2872 * Now we're encrypting. Begin returning 1 to the protocol main
2873 * function so that other things can run on top of the
2874 * transport. If we ever see a KEXINIT, we must go back to the
2875 * start.
2876 */
2877 while (!(ispkt && pktin.type == SSH2_MSG_KEXINIT)) {
2878 crReturn(1);
2879 }
2880 logevent("Server initiated key re-exchange");
2881 goto begin_key_exchange;
2882
2883 crFinish(1);
2884 }
2885
2886 /*
2887 * Add data to an SSH2 channel output buffer.
2888 */
2889 static void ssh2_add_channel_data(struct ssh_channel *c, char *buf, int len) {
2890 if (c->v2.outbufsize <
2891 c->v2.outbuflen + len) {
2892 c->v2.outbufsize =
2893 c->v2.outbuflen + len + 1024;
2894 c->v2.outbuffer = srealloc(c->v2.outbuffer,
2895 c->v2.outbufsize);
2896 }
2897 memcpy(c->v2.outbuffer + c->v2.outbuflen,
2898 buf, len);
2899 c->v2.outbuflen += len;
2900 }
2901
2902 /*
2903 * Attempt to send data on an SSH2 channel.
2904 */
2905 static void ssh2_try_send(struct ssh_channel *c) {
2906 while (c->v2.remwindow > 0 &&
2907 c->v2.outbuflen > 0) {
2908 unsigned len = c->v2.remwindow;
2909 if (len > c->v2.outbuflen)
2910 len = c->v2.outbuflen;
2911 if (len > c->v2.remmaxpkt)
2912 len = c->v2.remmaxpkt;
2913 ssh2_pkt_init(SSH2_MSG_CHANNEL_DATA);
2914 ssh2_pkt_adduint32(c->remoteid);
2915 ssh2_pkt_addstring_start();
2916 ssh2_pkt_addstring_data(c->v2.outbuffer, len);
2917 ssh2_pkt_send();
2918 c->v2.outbuflen -= len;
2919 memmove(c->v2.outbuffer, c->v2.outbuffer+len,
2920 c->v2.outbuflen);
2921 c->v2.remwindow -= len;
2922 }
2923 }
2924
2925 /*
2926 * Handle the SSH2 userauth and connection layers.
2927 */
2928 static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt)
2929 {
2930 static unsigned long remote_winsize;
2931 static unsigned long remote_maxpkt;
2932 static enum {
2933 AUTH_INVALID, AUTH_PUBLICKEY_AGENT, AUTH_PUBLICKEY_FILE, AUTH_PASSWORD
2934 } method;
2935 static enum {
2936 AUTH_TYPE_NONE,
2937 AUTH_TYPE_PUBLICKEY,
2938 AUTH_TYPE_PUBLICKEY_OFFER_LOUD,
2939 AUTH_TYPE_PUBLICKEY_OFFER_QUIET,
2940 AUTH_TYPE_PASSWORD
2941 } type;
2942 static int gotit, need_pw, can_pubkey, can_passwd;
2943 static int tried_pubkey_config, tried_agent;
2944 static int we_are_in;
2945 static char username[100];
2946 static char pwprompt[200];
2947 static char password[100];
2948
2949 crBegin;
2950
2951 /*
2952 * Request userauth protocol, and await a response to it.
2953 */
2954 ssh2_pkt_init(SSH2_MSG_SERVICE_REQUEST);
2955 ssh2_pkt_addstring("ssh-userauth");
2956 ssh2_pkt_send();
2957 crWaitUntilV(ispkt);
2958 if (pktin.type != SSH2_MSG_SERVICE_ACCEPT) {
2959 bombout(("Server refused user authentication protocol"));
2960 crReturnV;
2961 }
2962
2963 /*
2964 * We repeat this whole loop, including the username prompt,
2965 * until we manage a successful authentication. If the user
2966 * types the wrong _password_, they are sent back to the
2967 * beginning to try another username. (If they specify a
2968 * username in the config, they are never asked, even if they
2969 * do give a wrong password.)
2970 *
2971 * I think this best serves the needs of
2972 *
2973 * - the people who have no configuration, no keys, and just
2974 * want to try repeated (username,password) pairs until they
2975 * type both correctly
2976 *
2977 * - people who have keys and configuration but occasionally
2978 * need to fall back to passwords
2979 *
2980 * - people with a key held in Pageant, who might not have
2981 * logged in to a particular machine before; so they want to
2982 * type a username, and then _either_ their key will be
2983 * accepted, _or_ they will type a password. If they mistype
2984 * the username they will want to be able to get back and
2985 * retype it!
2986 */
2987 do {
2988 static int pos;
2989 static char c;
2990
2991 /*
2992 * Get a username.
2993 */
2994 pos = 0;
2995 if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
2996 if (ssh_get_line) {
2997 if (!ssh_get_line("login as: ",
2998 username, sizeof(username), FALSE)) {
2999 /*
3000 * get_line failed to get a username.
3001 * Terminate.
3002 */
3003 logevent("No username provided. Abandoning session.");
3004 ssh_state = SSH_STATE_CLOSED;
3005 crReturnV;
3006 }
3007 } else {
3008 c_write_str("login as: ");
3009 ssh_send_ok = 1;
3010 while (pos >= 0) {
3011 crWaitUntilV(!ispkt);
3012 while (inlen--) switch (c = *in++) {
3013 case 10: case 13:
3014 username[pos] = 0;
3015 pos = -1;
3016 break;
3017 case 8: case 127:
3018 if (pos > 0) {
3019 c_write_str("\b \b");
3020 pos--;
3021 }
3022 break;
3023 case 21: case 27:
3024 while (pos > 0) {
3025 c_write_str("\b \b");
3026 pos--;
3027 }
3028 break;
3029 case 3: case 4:
3030 random_save_seed();
3031 exit(0);
3032 break;
3033 default:
3034 if (((c >= ' ' && c <= '~') ||
3035 ((unsigned char)c >= 160)) && pos < 40) {
3036 username[pos++] = c;
3037 c_write(&c, 1);
3038 }
3039 break;
3040 }
3041 }
3042 }
3043 c_write_str("\r\n");
3044 username[strcspn(username, "\n\r")] = '\0';
3045 } else {
3046 char stuff[200];
3047 strncpy(username, cfg.username, 99);
3048 username[99] = '\0';
3049 if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
3050 sprintf(stuff, "Using username \"%s\".\r\n", username);
3051 c_write_str(stuff);
3052 }
3053 }
3054
3055 /*
3056 * Send an authentication request using method "none": (a)
3057 * just in case it succeeds, and (b) so that we know what
3058 * authentication methods we can usefully try next.
3059 */
3060 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
3061 ssh2_pkt_addstring(username);
3062 ssh2_pkt_addstring("ssh-connection"); /* service requested */
3063 ssh2_pkt_addstring("none"); /* method */
3064 ssh2_pkt_send();
3065 type = AUTH_TYPE_NONE;
3066 gotit = FALSE;
3067 we_are_in = FALSE;
3068
3069 tried_pubkey_config = FALSE;
3070 tried_agent = FALSE;
3071
3072 while (1) {
3073 /*
3074 * Wait for the result of the last authentication request.
3075 */
3076 if (!gotit)
3077 crWaitUntilV(ispkt);
3078 while (pktin.type == SSH2_MSG_USERAUTH_BANNER) {
3079 char *banner;
3080 int size;
3081 /*
3082 * Don't show the banner if we're operating in
3083 * non-verbose non-interactive mode. (It's probably
3084 * a script, which means nobody will read the
3085 * banner _anyway_, and moreover the printing of
3086 * the banner will screw up processing on the
3087 * output of (say) plink.)
3088 */
3089 if (flags & (FLAG_VERBOSE | FLAG_INTERACTIVE)) {
3090 ssh2_pkt_getstring(&banner, &size);
3091 if (banner)
3092 c_write_untrusted(banner, size);
3093 }
3094 crWaitUntilV(ispkt);
3095 }
3096 if (pktin.type == SSH2_MSG_USERAUTH_SUCCESS) {
3097 logevent("Access granted");
3098 we_are_in = TRUE;
3099 break;
3100 }
3101
3102 if (pktin.type != SSH2_MSG_USERAUTH_FAILURE) {
3103 bombout(("Strange packet received during authentication: type %d",
3104 pktin.type));
3105 crReturnV;
3106 }
3107
3108 gotit = FALSE;
3109
3110 /*
3111 * OK, we're now sitting on a USERAUTH_FAILURE message, so
3112 * we can look at the string in it and know what we can
3113 * helpfully try next.
3114 */
3115 {
3116 char *methods;
3117 int methlen;
3118 ssh2_pkt_getstring(&methods, &methlen);
3119 if (!ssh2_pkt_getbool()) {
3120 /*
3121 * We have received an unequivocal Access
3122 * Denied. This can translate to a variety of
3123 * messages:
3124 *
3125 * - if we'd just tried "none" authentication,
3126 * it's not worth printing anything at all
3127 *
3128 * - if we'd just tried a public key _offer_,
3129 * the message should be "Server refused our
3130 * key" (or no message at all if the key
3131 * came from Pageant)
3132 *
3133 * - if we'd just tried anything else, the
3134 * message really should be "Access denied".
3135 *
3136 * Additionally, if we'd just tried password
3137 * authentication, we should break out of this
3138 * whole loop so as to go back to the username
3139 * prompt.
3140 */
3141 if (type == AUTH_TYPE_NONE) {
3142 /* do nothing */
3143 } else if (type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD ||
3144 type == AUTH_TYPE_PUBLICKEY_OFFER_QUIET) {
3145 if (type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD)
3146 c_write_str("Server refused our key\r\n");
3147 logevent("Server refused public key");
3148 } else {
3149 c_write_str("Access denied\r\n");
3150 logevent("Access denied");
3151 if (type == AUTH_TYPE_PASSWORD) {
3152 we_are_in = FALSE;
3153 break;
3154 }
3155 }
3156 } else {
3157 c_write_str("Further authentication required\r\n");
3158 logevent("Further authentication required");
3159 }
3160
3161 can_pubkey = in_commasep_string("publickey", methods, methlen);
3162 can_passwd = in_commasep_string("password", methods, methlen);
3163 }
3164
3165 method = 0;
3166
3167 if (!method && can_pubkey && agent_exists && !tried_agent) {
3168 /*
3169 * Attempt public-key authentication using Pageant.
3170 */
3171 static unsigned char request[5], *response, *p;
3172 static int responselen;
3173 static int i, nkeys;
3174 static int authed = FALSE;
3175 void *r;
3176
3177 tried_agent = TRUE;
3178
3179 logevent("Pageant is running. Requesting keys.");
3180
3181 /* Request the keys held by the agent. */
3182 PUT_32BIT(request, 1);
3183 request[4] = SSH2_AGENTC_REQUEST_IDENTITIES;
3184 agent_query(request, 5, &r, &responselen);
3185 response = (unsigned char *)r;
3186 if (response && responselen >= 5 &&
3187 response[4] == SSH2_AGENT_IDENTITIES_ANSWER) {
3188 p = response + 5;
3189 nkeys = GET_32BIT(p); p += 4;
3190 { char buf[64]; sprintf(buf, "Pageant has %d SSH2 keys", nkeys);
3191 logevent(buf); }
3192 for (i = 0; i < nkeys; i++) {
3193 static char *pkblob, *alg, *commentp;
3194 static int pklen, alglen, commentlen;
3195 static int siglen, retlen, len;
3196 static char *q, *agentreq, *ret;
3197
3198 { char buf[64]; sprintf(buf, "Trying Pageant key #%d", i);
3199 logevent(buf); }
3200 pklen = GET_32BIT(p); p += 4;
3201 pkblob = p; p += pklen;
3202 alglen = GET_32BIT(pkblob);
3203 alg = pkblob + 4;
3204 commentlen = GET_32BIT(p); p += 4;
3205 commentp = p; p += commentlen;
3206 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
3207 ssh2_pkt_addstring(username);
3208 ssh2_pkt_addstring("ssh-connection");/* service requested */
3209 ssh2_pkt_addstring("publickey");/* method */
3210 ssh2_pkt_addbool(FALSE); /* no signature included */
3211 ssh2_pkt_addstring_start();
3212 ssh2_pkt_addstring_data(alg, alglen);
3213 ssh2_pkt_addstring_start();
3214 ssh2_pkt_addstring_data(pkblob, pklen);
3215 ssh2_pkt_send();
3216
3217 crWaitUntilV(ispkt);
3218 if (pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
3219 logevent("Key refused");
3220 continue;
3221 }
3222
3223 if (flags & FLAG_VERBOSE) {
3224 c_write_str("Authenticating with public key \"");
3225 c_write(commentp, commentlen);
3226 c_write_str("\" from agent\r\n");
3227 }
3228
3229 /*
3230 * Server is willing to accept the key.
3231 * Construct a SIGN_REQUEST.
3232 */
3233 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
3234 ssh2_pkt_addstring(username);
3235 ssh2_pkt_addstring("ssh-connection"); /* service requested */
3236 ssh2_pkt_addstring("publickey"); /* method */
3237 ssh2_pkt_addbool(TRUE);
3238 ssh2_pkt_addstring_start();
3239 ssh2_pkt_addstring_data(alg, alglen);
3240 ssh2_pkt_addstring_start();
3241 ssh2_pkt_addstring_data(pkblob, pklen);
3242
3243 siglen = pktout.length - 5 + 4 + 20;
3244 len = 1; /* message type */
3245 len += 4 + pklen; /* key blob */
3246 len += 4 + siglen; /* data to sign */
3247 len += 4; /* flags */
3248 agentreq = smalloc(4 + len);
3249 PUT_32BIT(agentreq, len);
3250 q = agentreq + 4;
3251 *q++ = SSH2_AGENTC_SIGN_REQUEST;
3252 PUT_32BIT(q, pklen); q += 4;
3253 memcpy(q, pkblob, pklen); q += pklen;
3254 PUT_32BIT(q, siglen); q += 4;
3255 /* Now the data to be signed... */
3256 PUT_32BIT(q, 20); q += 4;
3257 memcpy(q, ssh2_session_id, 20); q += 20;
3258 memcpy(q, pktout.data+5, pktout.length-5);
3259 q += pktout.length-5;
3260 /* And finally the (zero) flags word. */
3261 PUT_32BIT(q, 0);
3262 agent_query(agentreq, len+4, &ret, &retlen);
3263 sfree(agentreq);
3264 if (ret) {
3265 if (ret[4] == SSH2_AGENT_SIGN_RESPONSE) {
3266 logevent("Sending Pageant's response");
3267 ssh2_pkt_addstring_start();
3268 ssh2_pkt_addstring_data(ret+9, GET_32BIT(ret+5));
3269 ssh2_pkt_send();
3270 authed = TRUE;
3271 break;
3272 } else {
3273 logevent("Pageant failed to answer challenge");
3274 sfree(ret);
3275 }
3276 }
3277 }
3278 if (authed)
3279 continue;
3280 }
3281 }
3282
3283 if (!method && can_pubkey && *cfg.keyfile && !tried_pubkey_config) {
3284 unsigned char *pub_blob;
3285 char *algorithm, *comment;
3286 int pub_blob_len;
3287
3288 tried_pubkey_config = TRUE;
3289
3290 /*
3291 * Try the public key supplied in the configuration.
3292 *
3293 * First, offer the public blob to see if the server is
3294 * willing to accept it.
3295 */
3296 pub_blob = ssh2_userkey_loadpub(cfg.keyfile, &algorithm,
3297 &pub_blob_len);
3298 if (pub_blob) {
3299 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
3300 ssh2_pkt_addstring(username);
3301 ssh2_pkt_addstring("ssh-connection"); /* service requested */
3302 ssh2_pkt_addstring("publickey");/* method */
3303 ssh2_pkt_addbool(FALSE); /* no signature included */
3304 ssh2_pkt_addstring(algorithm);
3305 ssh2_pkt_addstring_start();
3306 ssh2_pkt_addstring_data(pub_blob, pub_blob_len);
3307 ssh2_pkt_send();
3308 logevent("Offered public key"); /* FIXME */
3309
3310 crWaitUntilV(ispkt);
3311 if (pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
3312 gotit = TRUE;
3313 type = AUTH_TYPE_PUBLICKEY_OFFER_LOUD;
3314 continue; /* key refused; give up on it */
3315 }
3316
3317 logevent("Offer of public key accepted");
3318 /*
3319 * Actually attempt a serious authentication using
3320 * the key.
3321 */
3322 if (ssh2_userkey_encrypted(cfg.keyfile, &comment)) {
3323 sprintf(pwprompt, "Passphrase for key \"%.100s\": ", comment);
3324 need_pw = TRUE;
3325 } else {
3326 need_pw = FALSE;
3327 }
3328 c_write_str("Authenticating with public key \"");
3329 c_write_str(comment);
3330 c_write_str("\"\r\n");
3331 method = AUTH_PUBLICKEY_FILE;
3332 }
3333 }
3334
3335 if (!method && can_passwd) {
3336 method = AUTH_PASSWORD;
3337 sprintf(pwprompt, "%.90s@%.90s's password: ", username, savedhost);
3338 need_pw = TRUE;
3339 }
3340
3341 if (need_pw) {
3342 if (ssh_get_line) {
3343 if (!ssh_get_line(pwprompt, password,
3344 sizeof(password), TRUE)) {
3345 /*
3346 * get_line failed to get a password (for
3347 * example because one was supplied on the
3348 * command line which has already failed to
3349 * work). Terminate.
3350 */
3351 logevent("No more passwords to try");
3352 ssh_state = SSH_STATE_CLOSED;
3353 crReturnV;
3354 }
3355 } else {
3356 static int pos = 0;
3357 static char c;
3358
3359 c_write_str(pwprompt);
3360 ssh_send_ok = 1;
3361
3362 pos = 0;
3363 while (pos >= 0) {
3364 crWaitUntilV(!ispkt);
3365 while (inlen--) switch (c = *in++) {
3366 case 10: case 13:
3367 password[pos] = 0;
3368 pos = -1;
3369 break;
3370 case 8: case 127:
3371 if (pos > 0)
3372 pos--;
3373 break;
3374 case 21: case 27:
3375 pos = 0;
3376 break;
3377 case 3: case 4:
3378 random_save_seed();
3379 exit(0);
3380 break;
3381 default:
3382 if (((c >= ' ' && c <= '~') ||
3383 ((unsigned char)c >= 160)) && pos < 40)
3384 password[pos++] = c;
3385 break;
3386 }
3387 }
3388 c_write_str("\r\n");
3389 }
3390 }
3391
3392 if (method == AUTH_PUBLICKEY_FILE) {
3393 /*
3394 * We have our passphrase. Now try the actual authentication.
3395 */
3396 struct ssh2_userkey *key;
3397
3398 key = ssh2_load_userkey(cfg.keyfile, password);
3399 if (key == SSH2_WRONG_PASSPHRASE || key == NULL) {
3400 if (key == SSH2_WRONG_PASSPHRASE) {
3401 c_write_str("Wrong passphrase\r\n");
3402 tried_pubkey_config = FALSE;
3403 } else {
3404 c_write_str("Unable to load private key\r\n");
3405 tried_pubkey_config = TRUE;
3406 }
3407 /* Send a spurious AUTH_NONE to return to the top. */
3408 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
3409 ssh2_pkt_addstring(username);
3410 ssh2_pkt_addstring("ssh-connection"); /* service requested */
3411 ssh2_pkt_addstring("none"); /* method */
3412 ssh2_pkt_send();
3413 type = AUTH_TYPE_NONE;
3414 } else {
3415 unsigned char *blob, *sigdata;
3416 int blob_len, sigdata_len;
3417
3418 /*
3419 * We have loaded the private key and the server
3420 * has announced that it's willing to accept it.
3421 * Hallelujah. Generate a signature and send it.
3422 */
3423 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
3424 ssh2_pkt_addstring(username);
3425 ssh2_pkt_addstring("ssh-connection"); /* service requested */
3426 ssh2_pkt_addstring("publickey"); /* method */
3427 ssh2_pkt_addbool(TRUE);
3428 ssh2_pkt_addstring(key->alg->name);
3429 blob = key->alg->public_blob(key->data, &blob_len);
3430 ssh2_pkt_addstring_start();
3431 ssh2_pkt_addstring_data(blob, blob_len);
3432 sfree(blob);
3433
3434 /*
3435 * The data to be signed is:
3436 *
3437 * string session-id
3438 *
3439 * followed by everything so far placed in the
3440 * outgoing packet.
3441 */
3442 sigdata_len = pktout.length - 5 + 4 + 20;
3443 sigdata = smalloc(sigdata_len);
3444 PUT_32BIT(sigdata, 20);
3445 memcpy(sigdata+4, ssh2_session_id, 20);
3446 memcpy(sigdata+24, pktout.data+5, pktout.length-5);
3447 blob = key->alg->sign(key->data, sigdata, sigdata_len, &blob_len);
3448 ssh2_pkt_addstring_start();
3449 ssh2_pkt_addstring_data(blob, blob_len);
3450 sfree(blob);
3451 sfree(sigdata);
3452
3453 ssh2_pkt_send();
3454 type = AUTH_TYPE_PUBLICKEY;
3455 }
3456 } else if (method == AUTH_PASSWORD) {
3457 /*
3458 * We send the password packet lumped tightly together with
3459 * an SSH_MSG_IGNORE packet. The IGNORE packet contains a
3460 * string long enough to make the total length of the two
3461 * packets constant. This should ensure that a passive
3462 * listener doing traffic analyis can't work out the length
3463 * of the password.
3464 *
3465 * For this to work, we need an assumption about the
3466 * maximum length of the password packet. I think 256 is
3467 * pretty conservative. Anyone using a password longer than
3468 * that probably doesn't have much to worry about from
3469 * people who find out how long their password is!
3470 */
3471 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
3472 ssh2_pkt_addstring(username);
3473 ssh2_pkt_addstring("ssh-connection"); /* service requested */
3474 ssh2_pkt_addstring("password");
3475 ssh2_pkt_addbool(FALSE);
3476 ssh2_pkt_addstring(password);
3477 ssh2_pkt_defer();
3478 /*
3479 * We'll include a string that's an exact multiple of the
3480 * cipher block size. If the cipher is NULL for some
3481 * reason, we don't do this trick at all because we gain
3482 * nothing by it.
3483 */
3484 if (cscipher) {
3485 int stringlen, i;
3486
3487 stringlen = (256 - deferred_len);
3488 stringlen += cscipher->blksize - 1;
3489 stringlen -= (stringlen % cscipher->blksize);
3490 if (cscomp) {
3491 /*
3492 * Temporarily disable actual compression,
3493 * so we can guarantee to get this string
3494 * exactly the length we want it. The
3495 * compression-disabling routine should
3496 * return an integer indicating how many
3497 * bytes we should adjust our string length
3498 * by.
3499 */
3500 stringlen -= cscomp->disable_compression();
3501 }
3502 ssh2_pkt_init(SSH2_MSG_IGNORE);
3503 ssh2_pkt_addstring_start();
3504 for (i = 0; i < stringlen; i++) {
3505 char c = (char)random_byte();
3506 ssh2_pkt_addstring_data(&c, 1);
3507 }
3508 ssh2_pkt_defer();
3509 }
3510 ssh_pkt_defersend();
3511 logevent("Sent password");
3512 type = AUTH_TYPE_PASSWORD;
3513 } else {
3514 c_write_str("No supported authentication methods left to try!\r\n");
3515 logevent("No supported authentications offered. Disconnecting");
3516 ssh2_pkt_init(SSH2_MSG_DISCONNECT);
3517 ssh2_pkt_adduint32(SSH2_DISCONNECT_BY_APPLICATION);
3518 ssh2_pkt_addstring("No supported authentication methods available");
3519 ssh2_pkt_addstring("en"); /* language tag */
3520 ssh2_pkt_send();
3521 ssh_state = SSH_STATE_CLOSED;
3522 crReturnV;
3523 }
3524 }
3525 } while (!we_are_in);
3526
3527 /*
3528 * Now we're authenticated for the connection protocol. The
3529 * connection protocol will automatically have started at this
3530 * point; there's no need to send SERVICE_REQUEST.
3531 */
3532
3533 /*
3534 * So now create a channel with a session in it.
3535 */
3536 ssh_channels = newtree234(ssh_channelcmp);
3537 mainchan = smalloc(sizeof(struct ssh_channel));
3538 mainchan->localid = alloc_channel_id();
3539 ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN);
3540 ssh2_pkt_addstring("session");
3541 ssh2_pkt_adduint32(mainchan->localid);
3542 ssh2_pkt_adduint32(0x8000UL); /* our window size */
3543 ssh2_pkt_adduint32(0x4000UL); /* our max pkt size */
3544 ssh2_pkt_send();
3545 crWaitUntilV(ispkt);
3546 if (pktin.type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
3547 bombout(("Server refused to open a session"));
3548 crReturnV;
3549 /* FIXME: error data comes back in FAILURE packet */
3550 }
3551 if (ssh2_pkt_getuint32() != mainchan->localid) {
3552 bombout(("Server's channel confirmation cited wrong channel"));
3553 crReturnV;
3554 }
3555 mainchan->remoteid = ssh2_pkt_getuint32();
3556 mainchan->type = CHAN_MAINSESSION;
3557 mainchan->closes = 0;
3558 mainchan->v2.remwindow = ssh2_pkt_getuint32();
3559 mainchan->v2.remmaxpkt = ssh2_pkt_getuint32();
3560 mainchan->v2.outbuffer = NULL;
3561 mainchan->v2.outbuflen = mainchan->v2.outbufsize = 0;
3562 add234(ssh_channels, mainchan);
3563 logevent("Opened channel for session");
3564
3565 /*
3566 * Potentially enable X11 forwarding.
3567 */
3568 if (cfg.x11_forward) {
3569 char proto[20], data[64];
3570 logevent("Requesting X11 forwarding");
3571 x11_invent_auth(proto, sizeof(proto), data, sizeof(data));
3572 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
3573 ssh2_pkt_adduint32(mainchan->remoteid);
3574 ssh2_pkt_addstring("x11-req");
3575 ssh2_pkt_addbool(1); /* want reply */
3576 ssh2_pkt_addbool(0); /* many connections */
3577 ssh2_pkt_addstring(proto);
3578 ssh2_pkt_addstring(data);
3579 ssh2_pkt_adduint32(0); /* screen number */
3580 ssh2_pkt_send();
3581
3582 do {
3583 crWaitUntilV(ispkt);
3584 if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
3585 unsigned i = ssh2_pkt_getuint32();
3586 struct ssh_channel *c;
3587 c = find234(ssh_channels, &i, ssh_channelfind);
3588 if (!c)
3589 continue; /* nonexistent channel */
3590 c->v2.remwindow += ssh2_pkt_getuint32();
3591 }
3592 } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
3593
3594 if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
3595 if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
3596 bombout(("Server got confused by X11 forwarding request"));
3597 crReturnV;
3598 }
3599 logevent("X11 forwarding refused");
3600 } else {
3601 logevent("X11 forwarding enabled");
3602 ssh_X11_fwd_enabled = TRUE;
3603 }
3604 }
3605
3606 /*
3607 * Potentially enable agent forwarding.
3608 */
3609 if (cfg.agentfwd && agent_exists()) {
3610 logevent("Requesting OpenSSH-style agent forwarding");
3611 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
3612 ssh2_pkt_adduint32(mainchan->remoteid);
3613 ssh2_pkt_addstring("auth-agent-req@openssh.com");
3614 ssh2_pkt_addbool(1); /* want reply */
3615 ssh2_pkt_send();
3616
3617 do {
3618 crWaitUntilV(ispkt);
3619 if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
3620 unsigned i = ssh2_pkt_getuint32();
3621 struct ssh_channel *c;
3622 c = find234(ssh_channels, &i, ssh_channelfind);
3623 if (!c)
3624 continue; /* nonexistent channel */
3625 c->v2.remwindow += ssh2_pkt_getuint32();
3626 }
3627 } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
3628
3629 if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
3630 if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
3631 bombout(("Server got confused by agent forwarding request"));
3632 crReturnV;
3633 }
3634 logevent("Agent forwarding refused");
3635 } else {
3636 logevent("Agent forwarding enabled");
3637 ssh_agentfwd_enabled = TRUE;
3638 }
3639 }
3640
3641 /*
3642 * Now allocate a pty for the session.
3643 */
3644 if (!cfg.nopty) {
3645 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
3646 ssh2_pkt_adduint32(mainchan->remoteid); /* recipient channel */
3647 ssh2_pkt_addstring("pty-req");
3648 ssh2_pkt_addbool(1); /* want reply */
3649 ssh2_pkt_addstring(cfg.termtype);
3650 ssh2_pkt_adduint32(cols);
3651 ssh2_pkt_adduint32(rows);
3652 ssh2_pkt_adduint32(0); /* pixel width */
3653 ssh2_pkt_adduint32(0); /* pixel height */
3654 ssh2_pkt_addstring_start();
3655 ssh2_pkt_addstring_data("\0", 1);/* TTY_OP_END, no special options */
3656 ssh2_pkt_send();
3657 ssh_state = SSH_STATE_INTERMED;
3658
3659 do {
3660 crWaitUntilV(ispkt);
3661 if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
3662 unsigned i = ssh2_pkt_getuint32();
3663 struct ssh_channel *c;
3664 c = find234(ssh_channels, &i, ssh_channelfind);
3665 if (!c)
3666 continue; /* nonexistent channel */
3667 c->v2.remwindow += ssh2_pkt_getuint32();
3668 }
3669 } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
3670
3671 if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
3672 if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
3673 bombout(("Server got confused by pty request"));
3674 crReturnV;
3675 }
3676 c_write_str("Server refused to allocate pty\r\n");
3677 ssh_editing = ssh_echoing = 1;
3678 } else {
3679 logevent("Allocated pty");
3680 }
3681 } else {
3682 ssh_editing = ssh_echoing = 1;
3683 }
3684
3685 /*
3686 * Start a shell or a remote command.
3687 */
3688 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
3689 ssh2_pkt_adduint32(mainchan->remoteid); /* recipient channel */
3690 if (cfg.ssh_subsys) {
3691 ssh2_pkt_addstring("subsystem");
3692 ssh2_pkt_addbool(1); /* want reply */
3693 ssh2_pkt_addstring(cfg.remote_cmd_ptr);
3694 } else if (*cfg.remote_cmd_ptr) {
3695 ssh2_pkt_addstring("exec");
3696 ssh2_pkt_addbool(1); /* want reply */
3697 ssh2_pkt_addstring(cfg.remote_cmd_ptr);
3698 } else {
3699 ssh2_pkt_addstring("shell");
3700 ssh2_pkt_addbool(1); /* want reply */
3701 }
3702 ssh2_pkt_send();
3703 do {
3704 crWaitUntilV(ispkt);
3705 if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
3706 unsigned i = ssh2_pkt_getuint32();
3707 struct ssh_channel *c;
3708 c = find234(ssh_channels, &i, ssh_channelfind);
3709 if (!c)
3710 continue; /* nonexistent channel */
3711 c->v2.remwindow += ssh2_pkt_getuint32();
3712 }
3713 } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
3714 if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
3715 if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
3716 bombout(("Server got confused by shell/command request"));
3717 crReturnV;
3718 }
3719 bombout(("Server refused to start a shell/command"));
3720 crReturnV;
3721 } else {
3722 logevent("Started a shell/command");
3723 }
3724
3725 ssh_state = SSH_STATE_SESSION;
3726 if (size_needed)
3727 ssh_size();
3728 if (eof_needed)
3729 ssh_special(TS_EOF);
3730
3731 /*
3732 * Transfer data!
3733 */
3734 ldisc_send(NULL, 0); /* cause ldisc to notice changes */
3735 ssh_send_ok = 1;
3736 while (1) {
3737 static int try_send;
3738 crReturnV;
3739 try_send = FALSE;
3740 if (ispkt) {
3741 if (pktin.type == SSH2_MSG_CHANNEL_DATA ||
3742 pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA) {
3743 char *data;
3744 int length;
3745 unsigned i = ssh2_pkt_getuint32();
3746 struct ssh_channel *c;
3747 c = find234(ssh_channels, &i, ssh_channelfind);
3748 if (!c)
3749 continue; /* nonexistent channel */
3750 if (pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
3751 ssh2_pkt_getuint32() != SSH2_EXTENDED_DATA_STDERR)
3752 continue; /* extended but not stderr */
3753 ssh2_pkt_getstring(&data, &length);
3754 if (data) {
3755 switch (c->type) {
3756 case CHAN_MAINSESSION:
3757 from_backend(pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA,
3758 data, length);
3759 break;
3760 case CHAN_X11:
3761 x11_send(c->u.x11.s, data, length);
3762 break;
3763 case CHAN_AGENT:
3764 while (length > 0) {
3765 if (c->u.a.lensofar < 4) {
3766 int l = min(4 - c->u.a.lensofar, length);
3767 memcpy(c->u.a.msglen + c->u.a.lensofar, data, l);
3768 data += l; length -= l; c->u.a.lensofar += l;
3769 }
3770 if (c->u.a.lensofar == 4) {
3771 c->u.a.totallen = 4 + GET_32BIT(c->u.a.msglen);
3772 c->u.a.message = smalloc(c->u.a.totallen);
3773 memcpy(c->u.a.message, c->u.a.msglen, 4);
3774 }
3775 if (c->u.a.lensofar >= 4 && length > 0) {
3776 int l = min(c->u.a.totallen - c->u.a.lensofar,
3777 length);
3778 memcpy(c->u.a.message + c->u.a.lensofar, data, l);
3779 data += l; length -= l; c->u.a.lensofar += l;
3780 }
3781 if (c->u.a.lensofar == c->u.a.totallen) {
3782 void *reply, *sentreply;
3783 int replylen;
3784 agent_query(c->u.a.message, c->u.a.totallen,
3785 &reply, &replylen);
3786 if (reply)
3787 sentreply = reply;
3788 else {
3789 /* Fake SSH_AGENT_FAILURE. */
3790 sentreply = "\0\0\0\1\5";
3791 replylen = 5;
3792 }
3793 ssh2_add_channel_data(c, sentreply, replylen);
3794 try_send = TRUE;
3795 if (reply)
3796 sfree(reply);
3797 sfree(c->u.a.message);
3798 c->u.a.lensofar = 0;
3799 }
3800 }
3801 break;
3802 }
3803 /*
3804 * Enlarge the window again at the remote
3805 * side, just in case it ever runs down and
3806 * they fail to send us any more data.
3807 */
3808 ssh2_pkt_init(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
3809 ssh2_pkt_adduint32(c->remoteid);
3810 ssh2_pkt_adduint32(length);
3811 ssh2_pkt_send();
3812 }
3813 } else if (pktin.type == SSH2_MSG_DISCONNECT) {
3814 ssh_state = SSH_STATE_CLOSED;
3815 logevent("Received disconnect message");
3816 crReturnV;
3817 } else if (pktin.type == SSH2_MSG_CHANNEL_REQUEST) {
3818 continue; /* exit status et al; ignore (FIXME?) */
3819 } else if (pktin.type == SSH2_MSG_CHANNEL_EOF) {
3820 unsigned i = ssh2_pkt_getuint32();
3821 struct ssh_channel *c;
3822
3823 c = find234(ssh_channels, &i, ssh_channelfind);
3824 if (!c)
3825 continue; /* nonexistent channel */
3826
3827 if (c->type == CHAN_X11) {
3828 /*
3829 * Remote EOF on an X11 channel means we should
3830 * wrap up and close the channel ourselves.
3831 */
3832 x11_close(c->u.x11.s);
3833 sshfwd_close(c);
3834 } else if (c->type == CHAN_AGENT) {
3835 sshfwd_close(c);
3836 }
3837 } else if (pktin.type == SSH2_MSG_CHANNEL_CLOSE) {
3838 unsigned i = ssh2_pkt_getuint32();
3839 struct ssh_channel *c;
3840
3841 c = find234(ssh_channels, &i, ssh_channelfind);
3842 if (!c)
3843 continue; /* nonexistent channel */
3844 if (c->closes == 0) {
3845 ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE);
3846 ssh2_pkt_adduint32(c->remoteid);
3847 ssh2_pkt_send();
3848 }
3849 /* Do pre-close processing on the channel. */
3850 switch (c->type) {
3851 case CHAN_MAINSESSION:
3852 break; /* nothing to see here, move along */
3853 case CHAN_X11:
3854 break;
3855 case CHAN_AGENT:
3856 break;
3857 }
3858 del234(ssh_channels, c);
3859 sfree(c->v2.outbuffer);
3860 sfree(c);
3861
3862 /*
3863 * See if that was the last channel left open.
3864 */
3865 if (count234(ssh_channels) == 0) {
3866 logevent("All channels closed. Disconnecting");
3867 ssh2_pkt_init(SSH2_MSG_DISCONNECT);
3868 ssh2_pkt_adduint32(SSH2_DISCONNECT_BY_APPLICATION);
3869 ssh2_pkt_addstring("All open channels closed");
3870 ssh2_pkt_addstring("en"); /* language tag */
3871 ssh2_pkt_send();
3872 ssh_state = SSH_STATE_CLOSED;
3873 crReturnV;
3874 }
3875 continue; /* remote sends close; ignore (FIXME) */
3876 } else if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
3877 unsigned i = ssh2_pkt_getuint32();
3878 struct ssh_channel *c;
3879 c = find234(ssh_channels, &i, ssh_channelfind);
3880 if (!c)
3881 continue; /* nonexistent channel */
3882 c->v2.remwindow += ssh2_pkt_getuint32();
3883 try_send = TRUE;
3884 } else if (pktin.type == SSH2_MSG_CHANNEL_OPEN) {
3885 char *type;
3886 int typelen;
3887 char *error = NULL;
3888 struct ssh_channel *c;
3889 ssh2_pkt_getstring(&type, &typelen);
3890 c = smalloc(sizeof(struct ssh_channel));
3891
3892 if (typelen == 3 && !memcmp(type, "x11", 3)) {
3893 if (!ssh_X11_fwd_enabled)
3894 error = "X11 forwarding is not enabled";
3895 else if ( x11_init(&c->u.x11.s, cfg.x11_display, c) != NULL ) {
3896 error = "Unable to open an X11 connection";
3897 } else {
3898 c->type = CHAN_X11;
3899 }
3900 } else if (typelen == 22 &&
3901 !memcmp(type, "auth-agent@openssh.com", 3)) {
3902 if (!ssh_agentfwd_enabled)
3903 error = "Agent forwarding is not enabled";
3904 else {
3905 c->type = CHAN_AGENT; /* identify channel type */
3906 c->u.a.lensofar = 0;
3907 }
3908 } else {
3909 error = "Unsupported channel type requested";
3910 }
3911
3912 c->remoteid = ssh2_pkt_getuint32();
3913 if (error) {
3914 ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_FAILURE);
3915 ssh2_pkt_adduint32(c->remoteid);
3916 ssh2_pkt_adduint32(SSH2_OPEN_CONNECT_FAILED);
3917 ssh2_pkt_addstring(error);
3918 ssh2_pkt_addstring("en"); /* language tag */
3919 ssh2_pkt_send();
3920 sfree(c);
3921 } else {
3922 c->localid = alloc_channel_id();
3923 c->closes = 0;
3924 c->v2.remwindow = ssh2_pkt_getuint32();
3925 c->v2.remmaxpkt = ssh2_pkt_getuint32();
3926 c->v2.outbuffer = NULL;
3927 c->v2.outbuflen = c->v2.outbufsize = 0;
3928 add234(ssh_channels, c);
3929 ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
3930 ssh2_pkt_adduint32(c->remoteid);
3931 ssh2_pkt_adduint32(c->localid);
3932 ssh2_pkt_adduint32(0x8000UL); /* our window size */
3933 ssh2_pkt_adduint32(0x4000UL); /* our max pkt size */
3934 ssh2_pkt_send();
3935 }
3936 } else {
3937 bombout(("Strange packet received: type %d", pktin.type));
3938 crReturnV;
3939 }
3940 } else {
3941 /*
3942 * We have spare data. Add it to the channel buffer.
3943 */
3944 ssh2_add_channel_data(mainchan, in, inlen);
3945 try_send = TRUE;
3946 }
3947 if (try_send) {
3948 int i;
3949 struct ssh_channel *c;
3950 /*
3951 * Try to send data on all channels if we can.
3952 */
3953 for (i = 0; NULL != (c = index234(ssh_channels, i)); i++)
3954 ssh2_try_send(c);
3955 }
3956 }
3957
3958 crFinishV;
3959 }
3960
3961 /*
3962 * Handle the top-level SSH2 protocol.
3963 */
3964 static void ssh2_protocol(unsigned char *in, int inlen, int ispkt)
3965 {
3966 if (do_ssh2_transport(in, inlen, ispkt) == 0)
3967 return;
3968 do_ssh2_authconn(in, inlen, ispkt);
3969 }
3970
3971 /*
3972 * Called to set up the connection.
3973 *
3974 * Returns an error message, or NULL on success.
3975 */
3976 static char *ssh_init (char *host, int port, char **realhost) {
3977 char *p;
3978
3979 #ifdef MSCRYPTOAPI
3980 if(crypto_startup() == 0)
3981 return "Microsoft high encryption pack not installed!";
3982 #endif
3983
3984 ssh_send_ok = 0;
3985 ssh_editing = 0;
3986 ssh_echoing = 0;
3987
3988 p = connect_to_host(host, port, realhost);
3989 if (p != NULL)
3990 return p;
3991
3992 return NULL;
3993 }
3994
3995 /*
3996 * Called to send data down the Telnet connection.
3997 */
3998 static void ssh_send (char *buf, int len) {
3999 if (s == NULL || ssh_protocol == NULL)
4000 return;
4001
4002 ssh_protocol(buf, len, 0);
4003 }
4004
4005 /*
4006 * Called to set the size of the window from SSH's POV.
4007 */
4008 static void ssh_size(void) {
4009 switch (ssh_state) {
4010 case SSH_STATE_BEFORE_SIZE:
4011 case SSH_STATE_PREPACKET:
4012 case SSH_STATE_CLOSED:
4013 break; /* do nothing */
4014 case SSH_STATE_INTERMED:
4015 size_needed = TRUE; /* buffer for later */
4016 break;
4017 case SSH_STATE_SESSION:
4018 if (!cfg.nopty) {
4019 if (ssh_version == 1) {
4020 send_packet(SSH1_CMSG_WINDOW_SIZE,
4021 PKT_INT, rows, PKT_INT, cols,
4022 PKT_INT, 0, PKT_INT, 0, PKT_END);
4023 } else {
4024 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
4025 ssh2_pkt_adduint32(mainchan->remoteid);
4026 ssh2_pkt_addstring("window-change");
4027 ssh2_pkt_addbool(0);
4028 ssh2_pkt_adduint32(cols);
4029 ssh2_pkt_adduint32(rows);
4030 ssh2_pkt_adduint32(0);
4031 ssh2_pkt_adduint32(0);
4032 ssh2_pkt_send();
4033 }
4034 }
4035 break;
4036 }
4037 }
4038
4039 /*
4040 * Send Telnet special codes. TS_EOF is useful for `plink', so you
4041 * can send an EOF and collect resulting output (e.g. `plink
4042 * hostname sort').
4043 */
4044 static void ssh_special (Telnet_Special code) {
4045 if (code == TS_EOF) {
4046 if (ssh_state != SSH_STATE_SESSION) {
4047 /*
4048 * Buffer the EOF in case we are pre-SESSION, so we can
4049 * send it as soon as we reach SESSION.
4050 */
4051 if (code == TS_EOF)
4052 eof_needed = TRUE;
4053 return;
4054 }
4055 if (ssh_version == 1) {
4056 send_packet(SSH1_CMSG_EOF, PKT_END);
4057 } else {
4058 ssh2_pkt_init(SSH2_MSG_CHANNEL_EOF);
4059 ssh2_pkt_adduint32(mainchan->remoteid);
4060 ssh2_pkt_send();
4061 }
4062 logevent("Sent EOF message");
4063 } else if (code == TS_PING) {
4064 if (ssh_state == SSH_STATE_CLOSED || ssh_state == SSH_STATE_PREPACKET)
4065 return;
4066 if (ssh_version == 1) {
4067 send_packet(SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
4068 } else {
4069 ssh2_pkt_init(SSH2_MSG_IGNORE);
4070 ssh2_pkt_addstring_start();
4071 ssh2_pkt_send();
4072 }
4073 } else {
4074 /* do nothing */
4075 }
4076 }
4077
4078 static Socket ssh_socket(void) { return s; }
4079
4080 static int ssh_sendok(void) { return ssh_send_ok; }
4081
4082 static int ssh_ldisc(int option) {
4083 if (option == LD_ECHO) return ssh_echoing;
4084 if (option == LD_EDIT) return ssh_editing;
4085 return FALSE;
4086 }
4087
4088 Backend ssh_backend = {
4089 ssh_init,
4090 ssh_send,
4091 ssh_size,
4092 ssh_special,
4093 ssh_socket,
4094 ssh_sendok,
4095 ssh_ldisc,
4096 22
4097 };
Local modifications for Simon Tatham's `PuTTY' SSH client and terminal emulator