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[u/mdw/putty] / ssh.c
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8df7a775 1#include <windows.h>
374330e2 2#include <stdio.h>
3#include <stdlib.h>
fb09bf1c 4#include <stdarg.h>
5#include <assert.h>
374330e2 6
7#include "putty.h"
dacbd0e8 8#include "tree234.h"
fb09bf1c 9#include "ssh.h"
374330e2 10
11#ifndef FALSE
12#define FALSE 0
13#endif
14#ifndef TRUE
15#define TRUE 1
16#endif
17
765c4200 18/* uncomment this for packet level debugging */
19/* #define DUMP_PACKETS */
20
fb09bf1c 21#define logevent(s) { logevent(s); \
67779be7 22 if ((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)) \
b4453f49 23 { fprintf(stderr, "%s\n", s); fflush(stderr); } }
fb09bf1c 24
3cd52910 25#define bombout(msg) ( ssh_state = SSH_STATE_CLOSED, \
4a8fc3c4 26 (s ? sk_close(s), s = NULL : 0), \
3cd52910 27 connection_fatal msg )
8d5de777 28
32874aea 29#define SSH1_MSG_DISCONNECT 1 /* 0x1 */
30#define SSH1_SMSG_PUBLIC_KEY 2 /* 0x2 */
31#define SSH1_CMSG_SESSION_KEY 3 /* 0x3 */
32#define SSH1_CMSG_USER 4 /* 0x4 */
33#define SSH1_CMSG_AUTH_RSA 6 /* 0x6 */
34#define SSH1_SMSG_AUTH_RSA_CHALLENGE 7 /* 0x7 */
35#define SSH1_CMSG_AUTH_RSA_RESPONSE 8 /* 0x8 */
36#define SSH1_CMSG_AUTH_PASSWORD 9 /* 0x9 */
37#define SSH1_CMSG_REQUEST_PTY 10 /* 0xa */
38#define SSH1_CMSG_WINDOW_SIZE 11 /* 0xb */
39#define SSH1_CMSG_EXEC_SHELL 12 /* 0xc */
40#define SSH1_CMSG_EXEC_CMD 13 /* 0xd */
41#define SSH1_SMSG_SUCCESS 14 /* 0xe */
42#define SSH1_SMSG_FAILURE 15 /* 0xf */
43#define SSH1_CMSG_STDIN_DATA 16 /* 0x10 */
44#define SSH1_SMSG_STDOUT_DATA 17 /* 0x11 */
45#define SSH1_SMSG_STDERR_DATA 18 /* 0x12 */
46#define SSH1_CMSG_EOF 19 /* 0x13 */
47#define SSH1_SMSG_EXIT_STATUS 20 /* 0x14 */
48#define SSH1_MSG_CHANNEL_OPEN_CONFIRMATION 21 /* 0x15 */
49#define SSH1_MSG_CHANNEL_OPEN_FAILURE 22 /* 0x16 */
50#define SSH1_MSG_CHANNEL_DATA 23 /* 0x17 */
51#define SSH1_MSG_CHANNEL_CLOSE 24 /* 0x18 */
52#define SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION 25 /* 0x19 */
53#define SSH1_SMSG_X11_OPEN 27 /* 0x1b */
54#define SSH1_CMSG_PORT_FORWARD_REQUEST 28 /* 0x1c */
55#define SSH1_MSG_PORT_OPEN 29 /* 0x1d */
56#define SSH1_CMSG_AGENT_REQUEST_FORWARDING 30 /* 0x1e */
57#define SSH1_SMSG_AGENT_OPEN 31 /* 0x1f */
58#define SSH1_MSG_IGNORE 32 /* 0x20 */
59#define SSH1_CMSG_EXIT_CONFIRMATION 33 /* 0x21 */
60#define SSH1_CMSG_X11_REQUEST_FORWARDING 34 /* 0x22 */
61#define SSH1_CMSG_AUTH_RHOSTS_RSA 35 /* 0x23 */
62#define SSH1_MSG_DEBUG 36 /* 0x24 */
63#define SSH1_CMSG_REQUEST_COMPRESSION 37 /* 0x25 */
64#define SSH1_CMSG_AUTH_TIS 39 /* 0x27 */
65#define SSH1_SMSG_AUTH_TIS_CHALLENGE 40 /* 0x28 */
66#define SSH1_CMSG_AUTH_TIS_RESPONSE 41 /* 0x29 */
67#define SSH1_CMSG_AUTH_CCARD 70 /* 0x46 */
68#define SSH1_SMSG_AUTH_CCARD_CHALLENGE 71 /* 0x47 */
69#define SSH1_CMSG_AUTH_CCARD_RESPONSE 72 /* 0x48 */
70
71#define SSH1_AUTH_TIS 5 /* 0x5 */
72#define SSH1_AUTH_CCARD 16 /* 0x10 */
73
74#define SSH1_PROTOFLAG_SCREEN_NUMBER 1 /* 0x1 */
b96dc54c 75/* Mask for protoflags we will echo back to server if seen */
32874aea 76#define SSH1_PROTOFLAGS_SUPPORTED 0 /* 0x1 */
77
78#define SSH2_MSG_DISCONNECT 1 /* 0x1 */
79#define SSH2_MSG_IGNORE 2 /* 0x2 */
80#define SSH2_MSG_UNIMPLEMENTED 3 /* 0x3 */
81#define SSH2_MSG_DEBUG 4 /* 0x4 */
82#define SSH2_MSG_SERVICE_REQUEST 5 /* 0x5 */
83#define SSH2_MSG_SERVICE_ACCEPT 6 /* 0x6 */
84#define SSH2_MSG_KEXINIT 20 /* 0x14 */
85#define SSH2_MSG_NEWKEYS 21 /* 0x15 */
86#define SSH2_MSG_KEXDH_INIT 30 /* 0x1e */
87#define SSH2_MSG_KEXDH_REPLY 31 /* 0x1f */
88#define SSH2_MSG_KEX_DH_GEX_REQUEST 30 /* 0x1e */
89#define SSH2_MSG_KEX_DH_GEX_GROUP 31 /* 0x1f */
90#define SSH2_MSG_KEX_DH_GEX_INIT 32 /* 0x20 */
91#define SSH2_MSG_KEX_DH_GEX_REPLY 33 /* 0x21 */
92#define SSH2_MSG_USERAUTH_REQUEST 50 /* 0x32 */
93#define SSH2_MSG_USERAUTH_FAILURE 51 /* 0x33 */
94#define SSH2_MSG_USERAUTH_SUCCESS 52 /* 0x34 */
95#define SSH2_MSG_USERAUTH_BANNER 53 /* 0x35 */
96#define SSH2_MSG_USERAUTH_PK_OK 60 /* 0x3c */
97#define SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ 60 /* 0x3c */
98#define SSH2_MSG_GLOBAL_REQUEST 80 /* 0x50 */
99#define SSH2_MSG_REQUEST_SUCCESS 81 /* 0x51 */
100#define SSH2_MSG_REQUEST_FAILURE 82 /* 0x52 */
101#define SSH2_MSG_CHANNEL_OPEN 90 /* 0x5a */
102#define SSH2_MSG_CHANNEL_OPEN_CONFIRMATION 91 /* 0x5b */
103#define SSH2_MSG_CHANNEL_OPEN_FAILURE 92 /* 0x5c */
104#define SSH2_MSG_CHANNEL_WINDOW_ADJUST 93 /* 0x5d */
105#define SSH2_MSG_CHANNEL_DATA 94 /* 0x5e */
106#define SSH2_MSG_CHANNEL_EXTENDED_DATA 95 /* 0x5f */
107#define SSH2_MSG_CHANNEL_EOF 96 /* 0x60 */
108#define SSH2_MSG_CHANNEL_CLOSE 97 /* 0x61 */
109#define SSH2_MSG_CHANNEL_REQUEST 98 /* 0x62 */
110#define SSH2_MSG_CHANNEL_SUCCESS 99 /* 0x63 */
111#define SSH2_MSG_CHANNEL_FAILURE 100 /* 0x64 */
112
113#define SSH2_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT 1 /* 0x1 */
114#define SSH2_DISCONNECT_PROTOCOL_ERROR 2 /* 0x2 */
115#define SSH2_DISCONNECT_KEY_EXCHANGE_FAILED 3 /* 0x3 */
116#define SSH2_DISCONNECT_HOST_AUTHENTICATION_FAILED 4 /* 0x4 */
117#define SSH2_DISCONNECT_MAC_ERROR 5 /* 0x5 */
118#define SSH2_DISCONNECT_COMPRESSION_ERROR 6 /* 0x6 */
119#define SSH2_DISCONNECT_SERVICE_NOT_AVAILABLE 7 /* 0x7 */
120#define SSH2_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED 8 /* 0x8 */
121#define SSH2_DISCONNECT_HOST_KEY_NOT_VERIFIABLE 9 /* 0x9 */
122#define SSH2_DISCONNECT_CONNECTION_LOST 10 /* 0xa */
123#define SSH2_DISCONNECT_BY_APPLICATION 11 /* 0xb */
124#define SSH2_DISCONNECT_TOO_MANY_CONNECTIONS 12 /* 0xc */
125#define SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER 13 /* 0xd */
126#define SSH2_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE 14 /* 0xe */
127#define SSH2_DISCONNECT_ILLEGAL_USER_NAME 15 /* 0xf */
38c4a8da 128
129static const char *const ssh2_disconnect_reasons[] = {
130 NULL,
131 "SSH_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT",
132 "SSH_DISCONNECT_PROTOCOL_ERROR",
133 "SSH_DISCONNECT_KEY_EXCHANGE_FAILED",
134 "SSH_DISCONNECT_HOST_AUTHENTICATION_FAILED",
135 "SSH_DISCONNECT_MAC_ERROR",
136 "SSH_DISCONNECT_COMPRESSION_ERROR",
137 "SSH_DISCONNECT_SERVICE_NOT_AVAILABLE",
138 "SSH_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED",
139 "SSH_DISCONNECT_HOST_KEY_NOT_VERIFIABLE",
140 "SSH_DISCONNECT_CONNECTION_LOST",
141 "SSH_DISCONNECT_BY_APPLICATION",
142 "SSH_DISCONNECT_TOO_MANY_CONNECTIONS",
143 "SSH_DISCONNECT_AUTH_CANCELLED_BY_USER",
144 "SSH_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE",
145 "SSH_DISCONNECT_ILLEGAL_USER_NAME",
146};
9005f3ba 147
32874aea 148#define SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED 1 /* 0x1 */
149#define SSH2_OPEN_CONNECT_FAILED 2 /* 0x2 */
150#define SSH2_OPEN_UNKNOWN_CHANNEL_TYPE 3 /* 0x3 */
151#define SSH2_OPEN_RESOURCE_SHORTAGE 4 /* 0x4 */
d211621f 152
32874aea 153#define SSH2_EXTENDED_DATA_STDERR 1 /* 0x1 */
fb09bf1c 154
7d503c31 155/*
156 * Various remote-bug flags.
157 */
158#define BUG_CHOKES_ON_SSH1_IGNORE 1
159#define BUG_SSH2_HMAC 2
160
fb09bf1c 161#define GET_32BIT(cp) \
162 (((unsigned long)(unsigned char)(cp)[0] << 24) | \
163 ((unsigned long)(unsigned char)(cp)[1] << 16) | \
164 ((unsigned long)(unsigned char)(cp)[2] << 8) | \
165 ((unsigned long)(unsigned char)(cp)[3]))
166
167#define PUT_32BIT(cp, value) { \
168 (cp)[0] = (unsigned char)((value) >> 24); \
169 (cp)[1] = (unsigned char)((value) >> 16); \
170 (cp)[2] = (unsigned char)((value) >> 8); \
171 (cp)[3] = (unsigned char)(value); }
172
7cca0d81 173enum { PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR, PKT_BIGNUM };
972a41c8 174
374330e2 175/* Coroutine mechanics for the sillier bits of the code */
176#define crBegin1 static int crLine = 0;
177#define crBegin2 switch(crLine) { case 0:;
178#define crBegin crBegin1; crBegin2;
179#define crFinish(z) } crLine = 0; return (z)
180#define crFinishV } crLine = 0; return
181#define crReturn(z) \
182 do {\
183 crLine=__LINE__; return (z); case __LINE__:;\
184 } while (0)
185#define crReturnV \
186 do {\
187 crLine=__LINE__; return; case __LINE__:;\
188 } while (0)
189#define crStop(z) do{ crLine = 0; return (z); }while(0)
190#define crStopV do{ crLine = 0; return; }while(0)
fb09bf1c 191#define crWaitUntil(c) do { crReturn(0); } while (!(c))
7cca0d81 192#define crWaitUntilV(c) do { crReturnV; } while (!(c))
374330e2 193
32874aea 194extern char *x11_init(Socket *, char *, void *);
195extern void x11_close(Socket);
196extern void x11_send(Socket, char *, int);
9c964e85 197extern void x11_invent_auth(char *, int, char *, int);
198
5e8358ad 199/*
200 * Ciphers for SSH2. We miss out single-DES because it isn't
201 * supported; also 3DES and Blowfish are both done differently from
202 * SSH1. (3DES uses outer chaining; Blowfish has the opposite
203 * endianness and different-sized keys.)
5e8358ad 204 */
0a3f1d48 205const static struct ssh2_ciphers *ciphers[] = {
206 &ssh2_aes,
207 &ssh2_blowfish,
208 &ssh2_3des,
8479e33c 209};
e5574168 210
a92dd380 211const static struct ssh_kex *kex_algs[] = {
a92dd380 212 &ssh_diffiehellman_gex,
32874aea 213 &ssh_diffiehellman
214};
e5574168 215
85cc02bb 216const static struct ssh_signkey *hostkey_algs[] = { &ssh_rsa, &ssh_dss };
e5574168 217
32874aea 218static void nullmac_key(unsigned char *key)
219{
220}
221static void nullmac_generate(unsigned char *blk, int len,
222 unsigned long seq)
223{
224}
225static int nullmac_verify(unsigned char *blk, int len, unsigned long seq)
226{
227 return 1;
228}
57476f6b 229const static struct ssh_mac ssh_mac_none = {
d39f364a 230 nullmac_key, nullmac_key, nullmac_generate, nullmac_verify, "none", 0
e5574168 231};
8b2715b2 232const static struct ssh_mac *macs[] = {
32874aea 233 &ssh_sha1, &ssh_md5, &ssh_mac_none
234};
8b2715b2 235const static struct ssh_mac *buggymacs[] = {
32874aea 236 &ssh_sha1_buggy, &ssh_md5, &ssh_mac_none
237};
e5574168 238
32874aea 239static void ssh_comp_none_init(void)
240{
241}
4ba9b64b 242static int ssh_comp_none_block(unsigned char *block, int len,
32874aea 243 unsigned char **outblock, int *outlen)
244{
245 return 0;
246}
247static int ssh_comp_none_disable(void)
248{
4ba9b64b 249 return 0;
250}
57476f6b 251const static struct ssh_compress ssh_comp_none = {
4ba9b64b 252 "none",
253 ssh_comp_none_init, ssh_comp_none_block,
63b00c83 254 ssh_comp_none_init, ssh_comp_none_block,
255 ssh_comp_none_disable
e5574168 256};
4ba9b64b 257extern const struct ssh_compress ssh_zlib;
258const static struct ssh_compress *compressions[] = {
32874aea 259 &ssh_zlib, &ssh_comp_none
260};
374330e2 261
32874aea 262enum { /* channel types */
783415f8 263 CHAN_MAINSESSION,
264 CHAN_X11,
265 CHAN_AGENT,
266};
267
dacbd0e8 268/*
269 * 2-3-4 tree storing channels.
270 */
271struct ssh_channel {
d211621f 272 unsigned remoteid, localid;
dacbd0e8 273 int type;
274 int closes;
783415f8 275 struct ssh2_data_channel {
32874aea 276 unsigned char *outbuffer;
277 unsigned outbuflen, outbufsize;
278 unsigned remwindow, remmaxpkt;
783415f8 279 } v2;
dacbd0e8 280 union {
32874aea 281 struct ssh_agent_channel {
282 unsigned char *message;
283 unsigned char msglen[4];
284 int lensofar, totallen;
285 } a;
286 struct ssh_x11_channel {
287 Socket s;
288 } x11;
dacbd0e8 289 } u;
290};
57476f6b 291
292struct Packet {
293 long length;
294 int type;
295 unsigned char *data;
296 unsigned char *body;
297 long savedpos;
298 long maxlen;
299};
300
0db56f73 301static SHA_State exhash, exhashbase;
57476f6b 302
8df7a775 303static Socket s = NULL;
57476f6b 304
305static unsigned char session_key[32];
4ba9b64b 306static int ssh1_compressing;
b96dc54c 307static int ssh1_remote_protoflags;
308static int ssh1_local_protoflags;
db7d555c 309static int ssh_agentfwd_enabled;
9c964e85 310static int ssh_X11_fwd_enabled;
7d503c31 311static int ssh_remote_bugs;
57476f6b 312static const struct ssh_cipher *cipher = NULL;
0a3f1d48 313static const struct ssh2_cipher *cscipher = NULL;
314static const struct ssh2_cipher *sccipher = NULL;
57476f6b 315static const struct ssh_mac *csmac = NULL;
316static const struct ssh_mac *scmac = NULL;
317static const struct ssh_compress *cscomp = NULL;
318static const struct ssh_compress *sccomp = NULL;
319static const struct ssh_kex *kex = NULL;
e055a386 320static const struct ssh_signkey *hostkey = NULL;
65a22376 321static unsigned char ssh2_session_id[20];
32874aea 322int (*ssh_get_line) (const char *prompt, char *str, int maxlen,
323 int is_pw) = NULL;
57476f6b 324
325static char *savedhost;
326static int savedport;
327static int ssh_send_ok;
0965bee0 328static int ssh_echoing, ssh_editing;
57476f6b 329
32874aea 330static tree234 *ssh_channels; /* indexed by local id */
57476f6b 331static struct ssh_channel *mainchan; /* primary session channel */
332
333static enum {
3687d221 334 SSH_STATE_PREPACKET,
57476f6b 335 SSH_STATE_BEFORE_SIZE,
336 SSH_STATE_INTERMED,
337 SSH_STATE_SESSION,
338 SSH_STATE_CLOSED
3687d221 339} ssh_state = SSH_STATE_PREPACKET;
57476f6b 340
3687d221 341static int size_needed = FALSE, eof_needed = FALSE;
57476f6b 342
343static struct Packet pktin = { 0, 0, NULL, NULL, 0 };
344static struct Packet pktout = { 0, 0, NULL, NULL, 0 };
b185170a 345static unsigned char *deferred_send_data = NULL;
346static int deferred_len = 0, deferred_size = 0;
57476f6b 347
348static int ssh_version;
32874aea 349static void (*ssh_protocol) (unsigned char *in, int inlen, int ispkt);
57476f6b 350static void ssh1_protocol(unsigned char *in, int inlen, int ispkt);
351static void ssh2_protocol(unsigned char *in, int inlen, int ispkt);
352static void ssh_size(void);
32874aea 353static void ssh_special(Telnet_Special);
783415f8 354static void ssh2_try_send(struct ssh_channel *c);
32874aea 355static void ssh2_add_channel_data(struct ssh_channel *c, char *buf,
356 int len);
57476f6b 357
32874aea 358static int (*s_rdpkt) (unsigned char **data, int *datalen);
57476f6b 359
360static struct rdpkt1_state_tag {
361 long len, pad, biglen, to_read;
362 unsigned long realcrc, gotcrc;
363 unsigned char *p;
364 int i;
365 int chunk;
366} rdpkt1_state;
367
960e736a 368static struct rdpkt2_state_tag {
369 long len, pad, payload, packetlen, maclen;
370 int i;
371 int cipherblk;
372 unsigned long incoming_sequence;
373} rdpkt2_state;
374
32874aea 375static int ssh_channelcmp(void *av, void *bv)
376{
377 struct ssh_channel *a = (struct ssh_channel *) av;
378 struct ssh_channel *b = (struct ssh_channel *) bv;
379 if (a->localid < b->localid)
380 return -1;
381 if (a->localid > b->localid)
382 return +1;
dacbd0e8 383 return 0;
384}
32874aea 385static int ssh_channelfind(void *av, void *bv)
386{
387 unsigned *a = (unsigned *) av;
388 struct ssh_channel *b = (struct ssh_channel *) bv;
389 if (*a < b->localid)
390 return -1;
391 if (*a > b->localid)
392 return +1;
dacbd0e8 393 return 0;
394}
395
32874aea 396static int alloc_channel_id(void)
397{
260f3dec 398 const unsigned CHANNEL_NUMBER_OFFSET = 256;
399 unsigned low, high, mid;
d2371c81 400 int tsize;
401 struct ssh_channel *c;
402
403 /*
404 * First-fit allocation of channel numbers: always pick the
405 * lowest unused one. To do this, binary-search using the
406 * counted B-tree to find the largest channel ID which is in a
407 * contiguous sequence from the beginning. (Precisely
408 * everything in that sequence must have ID equal to its tree
409 * index plus CHANNEL_NUMBER_OFFSET.)
410 */
411 tsize = count234(ssh_channels);
412
32874aea 413 low = -1;
414 high = tsize;
d2371c81 415 while (high - low > 1) {
416 mid = (high + low) / 2;
417 c = index234(ssh_channels, mid);
418 if (c->localid == mid + CHANNEL_NUMBER_OFFSET)
419 low = mid; /* this one is fine */
420 else
421 high = mid; /* this one is past it */
422 }
423 /*
424 * Now low points to either -1, or the tree index of the
425 * largest ID in the initial sequence.
426 */
427 {
428 unsigned i = low + 1 + CHANNEL_NUMBER_OFFSET;
429 assert(NULL == find234(ssh_channels, &i, ssh_channelfind));
430 }
431 return low + 1 + CHANNEL_NUMBER_OFFSET;
432}
433
32874aea 434static void c_write(char *buf, int len)
435{
67779be7 436 if ((flags & FLAG_STDERR)) {
32874aea 437 int i;
438 for (i = 0; i < len; i++)
439 if (buf[i] != '\r')
440 fputc(buf[i], stderr);
fb09bf1c 441 return;
442 }
fe50e814 443 from_backend(1, buf, len);
3bdaf79d 444}
445
32874aea 446static void c_write_untrusted(char *buf, int len)
447{
a209e957 448 int i;
449 for (i = 0; i < len; i++) {
32874aea 450 if (buf[i] == '\n')
451 c_write("\r\n", 2);
452 else if ((buf[i] & 0x60) || (buf[i] == '\r'))
453 c_write(buf + i, 1);
a209e957 454 }
455}
456
32874aea 457static void c_write_str(char *buf)
458{
1408a877 459 c_write(buf, strlen(buf));
460}
461
fb09bf1c 462/*
463 * Collect incoming data in the incoming packet buffer.
e5574168 464 * Decipher and verify the packet when it is completely read.
465 * Drop SSH1_MSG_DEBUG and SSH1_MSG_IGNORE packets.
fb09bf1c 466 * Update the *data and *datalen variables.
467 * Return the additional nr of bytes needed, or 0 when
468 * a complete packet is available.
469 */
e5574168 470static int ssh1_rdpkt(unsigned char **data, int *datalen)
fb09bf1c 471{
57476f6b 472 struct rdpkt1_state_tag *st = &rdpkt1_state;
374330e2 473
474 crBegin;
374330e2 475
32874aea 476 next_packet:
37508af4 477
fb09bf1c 478 pktin.type = 0;
479 pktin.length = 0;
374330e2 480
57476f6b 481 for (st->i = st->len = 0; st->i < 4; st->i++) {
fb09bf1c 482 while ((*datalen) == 0)
32874aea 483 crReturn(4 - st->i);
57476f6b 484 st->len = (st->len << 8) + **data;
fb09bf1c 485 (*data)++, (*datalen)--;
486 }
374330e2 487
fb09bf1c 488#ifdef FWHACK
32874aea 489 if (st->len == 0x52656d6f) { /* "Remo"te server has closed ... */
490 st->len = 0x300; /* big enough to carry to end */
fb09bf1c 491 }
492#endif
374330e2 493
57476f6b 494 st->pad = 8 - (st->len % 8);
495 st->biglen = st->len + st->pad;
496 pktin.length = st->len - 5;
fb09bf1c 497
57476f6b 498 if (pktin.maxlen < st->biglen) {
499 pktin.maxlen = st->biglen;
32874aea 500 pktin.data = (pktin.data == NULL ? smalloc(st->biglen + APIEXTRA) :
501 srealloc(pktin.data, st->biglen + APIEXTRA));
fb09bf1c 502 if (!pktin.data)
503 fatalbox("Out of memory");
504 }
374330e2 505
57476f6b 506 st->to_read = st->biglen;
507 st->p = pktin.data;
508 while (st->to_read > 0) {
32874aea 509 st->chunk = st->to_read;
fb09bf1c 510 while ((*datalen) == 0)
57476f6b 511 crReturn(st->to_read);
512 if (st->chunk > (*datalen))
513 st->chunk = (*datalen);
514 memcpy(st->p, *data, st->chunk);
515 *data += st->chunk;
516 *datalen -= st->chunk;
517 st->p += st->chunk;
518 st->to_read -= st->chunk;
fb09bf1c 519 }
374330e2 520
fb09bf1c 521 if (cipher)
57476f6b 522 cipher->decrypt(pktin.data, st->biglen);
765c4200 523#ifdef DUMP_PACKETS
524 debug(("Got packet len=%d pad=%d\n", st->len, st->pad));
525 dmemdump(pktin.data, st->biglen);
698a5108 526#endif
374330e2 527
32874aea 528 st->realcrc = crc32(pktin.data, st->biglen - 4);
529 st->gotcrc = GET_32BIT(pktin.data + st->biglen - 4);
57476f6b 530 if (st->gotcrc != st->realcrc) {
8d5de777 531 bombout(("Incorrect CRC received on packet"));
32874aea 532 crReturn(0);
fb09bf1c 533 }
572f871e 534
4ba9b64b 535 pktin.body = pktin.data + st->pad + 1;
536
537 if (ssh1_compressing) {
538 unsigned char *decompblk;
539 int decomplen;
765c4200 540#ifdef DUMP_PACKETS
541 debug(("Packet payload pre-decompression:\n"));
32874aea 542 dmemdump(pktin.body - 1, pktin.length + 1);
4ba9b64b 543#endif
32874aea 544 zlib_decompress_block(pktin.body - 1, pktin.length + 1,
4ba9b64b 545 &decompblk, &decomplen);
546
547 if (pktin.maxlen < st->pad + decomplen) {
548 pktin.maxlen = st->pad + decomplen;
32874aea 549 pktin.data = srealloc(pktin.data, pktin.maxlen + APIEXTRA);
550 pktin.body = pktin.data + st->pad + 1;
4ba9b64b 551 if (!pktin.data)
552 fatalbox("Out of memory");
553 }
554
32874aea 555 memcpy(pktin.body - 1, decompblk, decomplen);
dcbde236 556 sfree(decompblk);
32874aea 557 pktin.length = decomplen - 1;
765c4200 558#ifdef DUMP_PACKETS
559 debug(("Packet payload post-decompression:\n"));
32874aea 560 dmemdump(pktin.body - 1, pktin.length + 1);
4ba9b64b 561#endif
562 }
563
e5574168 564 if (pktin.type == SSH1_SMSG_STDOUT_DATA ||
32874aea 565 pktin.type == SSH1_SMSG_STDERR_DATA ||
566 pktin.type == SSH1_MSG_DEBUG ||
567 pktin.type == SSH1_SMSG_AUTH_TIS_CHALLENGE ||
568 pktin.type == SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
fb09bf1c 569 long strlen = GET_32BIT(pktin.body);
8d5de777 570 if (strlen + 4 != pktin.length) {
571 bombout(("Received data packet with bogus string length"));
32874aea 572 crReturn(0);
573 }
fb09bf1c 574 }
575
4ba9b64b 576 pktin.type = pktin.body[-1];
577
e5574168 578 if (pktin.type == SSH1_MSG_DEBUG) {
fb09bf1c 579 /* log debug message */
580 char buf[80];
581 int strlen = GET_32BIT(pktin.body);
582 strcpy(buf, "Remote: ");
32874aea 583 if (strlen > 70)
584 strlen = 70;
585 memcpy(buf + 8, pktin.body + 4, strlen);
586 buf[8 + strlen] = '\0';
fb09bf1c 587 logevent(buf);
588 goto next_packet;
e5574168 589 } else if (pktin.type == SSH1_MSG_IGNORE) {
fb09bf1c 590 /* do nothing */
591 goto next_packet;
592 }
593
38c4a8da 594 if (pktin.type == SSH1_MSG_DISCONNECT) {
595 /* log reason code in disconnect message */
596 char buf[256];
260f3dec 597 unsigned msglen = GET_32BIT(pktin.body);
598 unsigned nowlen;
38c4a8da 599 strcpy(buf, "Remote sent disconnect: ");
600 nowlen = strlen(buf);
32874aea 601 if (msglen > sizeof(buf) - nowlen - 1)
602 msglen = sizeof(buf) - nowlen - 1;
603 memcpy(buf + nowlen, pktin.body + 4, msglen);
604 buf[nowlen + msglen] = '\0';
38c4a8da 605 logevent(buf);
606 }
607
fb09bf1c 608 crFinish(0);
609}
610
e5574168 611static int ssh2_rdpkt(unsigned char **data, int *datalen)
612{
960e736a 613 struct rdpkt2_state_tag *st = &rdpkt2_state;
e5574168 614
615 crBegin;
616
32874aea 617 next_packet:
e5574168 618 pktin.type = 0;
619 pktin.length = 0;
960e736a 620 if (sccipher)
32874aea 621 st->cipherblk = sccipher->blksize;
e5574168 622 else
32874aea 623 st->cipherblk = 8;
960e736a 624 if (st->cipherblk < 8)
32874aea 625 st->cipherblk = 8;
960e736a 626
627 if (pktin.maxlen < st->cipherblk) {
628 pktin.maxlen = st->cipherblk;
32874aea 629 pktin.data =
630 (pktin.data ==
631 NULL ? smalloc(st->cipherblk +
632 APIEXTRA) : srealloc(pktin.data,
633 st->cipherblk +
634 APIEXTRA));
e5574168 635 if (!pktin.data)
636 fatalbox("Out of memory");
637 }
638
639 /*
640 * Acquire and decrypt the first block of the packet. This will
641 * contain the length and padding details.
642 */
32874aea 643 for (st->i = st->len = 0; st->i < st->cipherblk; st->i++) {
e5574168 644 while ((*datalen) == 0)
32874aea 645 crReturn(st->cipherblk - st->i);
960e736a 646 pktin.data[st->i] = *(*data)++;
32874aea 647 (*datalen)--;
e5574168 648 }
649#ifdef FWHACK
32874aea 650 if (!memcmp(pktin.data, "Remo", 4)) { /* "Remo"te server has closed ... */
651 /* FIXME */
e5574168 652 }
653#endif
654 if (sccipher)
32874aea 655 sccipher->decrypt(pktin.data, st->cipherblk);
e5574168 656
657 /*
658 * Now get the length and padding figures.
659 */
960e736a 660 st->len = GET_32BIT(pktin.data);
661 st->pad = pktin.data[4];
e5574168 662
663 /*
664 * This enables us to deduce the payload length.
665 */
960e736a 666 st->payload = st->len - st->pad - 1;
e5574168 667
960e736a 668 pktin.length = st->payload + 5;
e5574168 669
670 /*
671 * So now we can work out the total packet length.
672 */
960e736a 673 st->packetlen = st->len + 4;
674 st->maclen = scmac ? scmac->len : 0;
e5574168 675
676 /*
677 * Adjust memory allocation if packet is too big.
678 */
32874aea 679 if (pktin.maxlen < st->packetlen + st->maclen) {
680 pktin.maxlen = st->packetlen + st->maclen;
681 pktin.data =
682 (pktin.data ==
683 NULL ? smalloc(pktin.maxlen + APIEXTRA) : srealloc(pktin.data,
684 pktin.maxlen
685 +
686 APIEXTRA));
e5574168 687 if (!pktin.data)
688 fatalbox("Out of memory");
689 }
690
691 /*
692 * Read and decrypt the remainder of the packet.
693 */
32874aea 694 for (st->i = st->cipherblk; st->i < st->packetlen + st->maclen;
695 st->i++) {
e5574168 696 while ((*datalen) == 0)
960e736a 697 crReturn(st->packetlen + st->maclen - st->i);
698 pktin.data[st->i] = *(*data)++;
32874aea 699 (*datalen)--;
e5574168 700 }
701 /* Decrypt everything _except_ the MAC. */
702 if (sccipher)
32874aea 703 sccipher->decrypt(pktin.data + st->cipherblk,
704 st->packetlen - st->cipherblk);
e5574168 705
765c4200 706#ifdef DUMP_PACKETS
707 debug(("Got packet len=%d pad=%d\n", st->len, st->pad));
708 dmemdump(pktin.data, st->packetlen);
7cca0d81 709#endif
d39f364a 710
e5574168 711 /*
712 * Check the MAC.
713 */
32874aea 714 if (scmac
715 && !scmac->verify(pktin.data, st->len + 4,
716 st->incoming_sequence)) {
8d5de777 717 bombout(("Incorrect MAC received on packet"));
32874aea 718 crReturn(0);
8d5de777 719 }
32874aea 720 st->incoming_sequence++; /* whether or not we MACed */
e5574168 721
4ba9b64b 722 /*
723 * Decompress packet payload.
724 */
725 {
726 unsigned char *newpayload;
727 int newlen;
32874aea 728 if (sccomp && sccomp->decompress(pktin.data + 5, pktin.length - 5,
4ba9b64b 729 &newpayload, &newlen)) {
32874aea 730 if (pktin.maxlen < newlen + 5) {
731 pktin.maxlen = newlen + 5;
732 pktin.data =
733 (pktin.data ==
734 NULL ? smalloc(pktin.maxlen +
735 APIEXTRA) : srealloc(pktin.data,
736 pktin.maxlen +
737 APIEXTRA));
4ba9b64b 738 if (!pktin.data)
739 fatalbox("Out of memory");
740 }
741 pktin.length = 5 + newlen;
32874aea 742 memcpy(pktin.data + 5, newpayload, newlen);
765c4200 743#ifdef DUMP_PACKETS
744 debug(("Post-decompression payload:\n"));
32874aea 745 dmemdump(pktin.data + 5, newlen);
4ba9b64b 746#endif
747
dcbde236 748 sfree(newpayload);
4ba9b64b 749 }
750 }
751
e5574168 752 pktin.savedpos = 6;
753 pktin.type = pktin.data[5];
e5574168 754
7cca0d81 755 if (pktin.type == SSH2_MSG_IGNORE || pktin.type == SSH2_MSG_DEBUG)
32874aea 756 goto next_packet; /* FIXME: print DEBUG message */
e5574168 757
38c4a8da 758 if (pktin.type == SSH2_MSG_DISCONNECT) {
759 /* log reason code in disconnect message */
760 char buf[256];
32874aea 761 int reason = GET_32BIT(pktin.data + 6);
762 unsigned msglen = GET_32BIT(pktin.data + 10);
260f3dec 763 unsigned nowlen;
38c4a8da 764 if (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) {
765 sprintf(buf, "Received disconnect message (%s)",
766 ssh2_disconnect_reasons[reason]);
767 } else {
32874aea 768 sprintf(buf, "Received disconnect message (unknown type %d)",
769 reason);
38c4a8da 770 }
771 logevent(buf);
772 strcpy(buf, "Disconnection message text: ");
773 nowlen = strlen(buf);
32874aea 774 if (msglen > sizeof(buf) - nowlen - 1)
775 msglen = sizeof(buf) - nowlen - 1;
776 memcpy(buf + nowlen, pktin.data + 14, msglen);
777 buf[nowlen + msglen] = '\0';
38c4a8da 778 logevent(buf);
779 }
780
e5574168 781 crFinish(0);
782}
783
32874aea 784static void ssh1_pktout_size(int len)
785{
374330e2 786 int pad, biglen;
787
788 len += 5; /* type and CRC */
32874aea 789 pad = 8 - (len % 8);
374330e2 790 biglen = len + pad;
791
32874aea 792 pktout.length = len - 5;
374330e2 793 if (pktout.maxlen < biglen) {
794 pktout.maxlen = biglen;
8f203108 795#ifdef MSCRYPTOAPI
fb09bf1c 796 /* Allocate enough buffer space for extra block
8f203108 797 * for MS CryptEncrypt() */
32874aea 798 pktout.data = (pktout.data == NULL ? smalloc(biglen + 12) :
799 srealloc(pktout.data, biglen + 12));
8f203108 800#else
32874aea 801 pktout.data = (pktout.data == NULL ? smalloc(biglen + 4) :
802 srealloc(pktout.data, biglen + 4));
8f203108 803#endif
374330e2 804 if (!pktout.data)
805 fatalbox("Out of memory");
806 }
32874aea 807 pktout.body = pktout.data + 4 + pad + 1;
4ba9b64b 808}
374330e2 809
32874aea 810static void s_wrpkt_start(int type, int len)
811{
4ba9b64b 812 ssh1_pktout_size(len);
374330e2 813 pktout.type = type;
374330e2 814}
815
32874aea 816static int s_wrpkt_prepare(void)
817{
374330e2 818 int pad, len, biglen, i;
819 unsigned long crc;
820
4ba9b64b 821 pktout.body[-1] = pktout.type;
822
765c4200 823#ifdef DUMP_PACKETS
7d503c31 824 debug(("Packet payload pre-compression:\n"));
32874aea 825 dmemdump(pktout.body - 1, pktout.length + 1);
7d503c31 826#endif
827
4ba9b64b 828 if (ssh1_compressing) {
829 unsigned char *compblk;
830 int complen;
32874aea 831 zlib_compress_block(pktout.body - 1, pktout.length + 1,
4ba9b64b 832 &compblk, &complen);
32874aea 833 ssh1_pktout_size(complen - 1);
834 memcpy(pktout.body - 1, compblk, complen);
dcbde236 835 sfree(compblk);
765c4200 836#ifdef DUMP_PACKETS
4ba9b64b 837 debug(("Packet payload post-compression:\n"));
32874aea 838 dmemdump(pktout.body - 1, pktout.length + 1);
4ba9b64b 839#endif
840 }
841
374330e2 842 len = pktout.length + 5; /* type and CRC */
32874aea 843 pad = 8 - (len % 8);
374330e2 844 biglen = len + pad;
845
32874aea 846 for (i = 0; i < pad; i++)
847 pktout.data[i + 4] = random_byte();
848 crc = crc32(pktout.data + 4, biglen - 4);
849 PUT_32BIT(pktout.data + biglen, crc);
fb09bf1c 850 PUT_32BIT(pktout.data, len);
374330e2 851
765c4200 852#ifdef DUMP_PACKETS
32874aea 853 debug(("Sending packet len=%d\n", biglen + 4));
854 dmemdump(pktout.data, biglen + 4);
698a5108 855#endif
374330e2 856 if (cipher)
32874aea 857 cipher->encrypt(pktout.data + 4, biglen);
374330e2 858
32874aea 859 return biglen + 4;
39065bed 860}
861
32874aea 862static void s_wrpkt(void)
863{
39065bed 864 int len;
865 len = s_wrpkt_prepare();
866 sk_write(s, pktout.data, len);
867}
868
32874aea 869static void s_wrpkt_defer(void)
870{
39065bed 871 int len;
872 len = s_wrpkt_prepare();
873 if (deferred_len + len > deferred_size) {
32874aea 874 deferred_size = deferred_len + len + 128;
875 deferred_send_data = srealloc(deferred_send_data, deferred_size);
39065bed 876 }
32874aea 877 memcpy(deferred_send_data + deferred_len, pktout.data, len);
39065bed 878 deferred_len += len;
374330e2 879}
880
fb09bf1c 881/*
39065bed 882 * Construct a packet with the specified contents.
fb09bf1c 883 */
39065bed 884static void construct_packet(int pkttype, va_list ap1, va_list ap2)
fb09bf1c 885{
fb09bf1c 886 unsigned char *p, *argp, argchar;
887 unsigned long argint;
888 int pktlen, argtype, arglen;
7cca0d81 889 Bignum bn;
fb09bf1c 890
891 pktlen = 0;
39065bed 892 while ((argtype = va_arg(ap1, int)) != PKT_END) {
fb09bf1c 893 switch (argtype) {
894 case PKT_INT:
39065bed 895 (void) va_arg(ap1, int);
fb09bf1c 896 pktlen += 4;
897 break;
898 case PKT_CHAR:
39065bed 899 (void) va_arg(ap1, char);
fb09bf1c 900 pktlen++;
901 break;
902 case PKT_DATA:
39065bed 903 (void) va_arg(ap1, unsigned char *);
904 arglen = va_arg(ap1, int);
fb09bf1c 905 pktlen += arglen;
906 break;
907 case PKT_STR:
39065bed 908 argp = va_arg(ap1, unsigned char *);
fb09bf1c 909 arglen = strlen(argp);
910 pktlen += 4 + arglen;
911 break;
7cca0d81 912 case PKT_BIGNUM:
39065bed 913 bn = va_arg(ap1, Bignum);
32874aea 914 pktlen += ssh1_bignum_length(bn);
7cca0d81 915 break;
fb09bf1c 916 default:
917 assert(0);
918 }
919 }
fb09bf1c 920
921 s_wrpkt_start(pkttype, pktlen);
922 p = pktout.body;
923
39065bed 924 while ((argtype = va_arg(ap2, int)) != PKT_END) {
fb09bf1c 925 switch (argtype) {
926 case PKT_INT:
39065bed 927 argint = va_arg(ap2, int);
fb09bf1c 928 PUT_32BIT(p, argint);
929 p += 4;
930 break;
931 case PKT_CHAR:
39065bed 932 argchar = va_arg(ap2, unsigned char);
fb09bf1c 933 *p = argchar;
934 p++;
935 break;
936 case PKT_DATA:
39065bed 937 argp = va_arg(ap2, unsigned char *);
938 arglen = va_arg(ap2, int);
fb09bf1c 939 memcpy(p, argp, arglen);
940 p += arglen;
941 break;
942 case PKT_STR:
39065bed 943 argp = va_arg(ap2, unsigned char *);
fb09bf1c 944 arglen = strlen(argp);
945 PUT_32BIT(p, arglen);
946 memcpy(p + 4, argp, arglen);
947 p += 4 + arglen;
948 break;
7cca0d81 949 case PKT_BIGNUM:
39065bed 950 bn = va_arg(ap2, Bignum);
32874aea 951 p += ssh1_write_bignum(p, bn);
7cca0d81 952 break;
fb09bf1c 953 }
954 }
39065bed 955}
fb09bf1c 956
32874aea 957static void send_packet(int pkttype, ...)
958{
39065bed 959 va_list ap1, ap2;
960 va_start(ap1, pkttype);
961 va_start(ap2, pkttype);
962 construct_packet(pkttype, ap1, ap2);
fb09bf1c 963 s_wrpkt();
964}
965
32874aea 966static void defer_packet(int pkttype, ...)
967{
39065bed 968 va_list ap1, ap2;
969 va_start(ap1, pkttype);
970 va_start(ap2, pkttype);
971 construct_packet(pkttype, ap1, ap2);
972 s_wrpkt_defer();
973}
974
32874aea 975static int ssh_versioncmp(char *a, char *b)
976{
9697bfd2 977 char *ae, *be;
978 unsigned long av, bv;
979
43aa02a7 980 av = strtoul(a, &ae, 10);
981 bv = strtoul(b, &be, 10);
32874aea 982 if (av != bv)
983 return (av < bv ? -1 : +1);
984 if (*ae == '.')
985 ae++;
986 if (*be == '.')
987 be++;
43aa02a7 988 av = strtoul(ae, &ae, 10);
989 bv = strtoul(be, &be, 10);
32874aea 990 if (av != bv)
991 return (av < bv ? -1 : +1);
9697bfd2 992 return 0;
993}
994
e5574168 995
996/*
a92dd380 997 * Utility routines for putting an SSH-protocol `string' and
998 * `uint32' into a SHA state.
e5574168 999 */
1000#include <stdio.h>
32874aea 1001static void sha_string(SHA_State * s, void *str, int len)
1002{
e5574168 1003 unsigned char lenblk[4];
e5574168 1004 PUT_32BIT(lenblk, len);
e5574168 1005 SHA_Bytes(s, lenblk, 4);
e5574168 1006 SHA_Bytes(s, str, len);
1007}
1008
32874aea 1009static void sha_uint32(SHA_State * s, unsigned i)
1010{
a92dd380 1011 unsigned char intblk[4];
1012 PUT_32BIT(intblk, i);
1013 SHA_Bytes(s, intblk, 4);
1014}
1015
7cca0d81 1016/*
1017 * SSH2 packet construction functions.
1018 */
32874aea 1019static void ssh2_pkt_ensure(int length)
1020{
783415f8 1021 if (pktout.maxlen < length) {
32874aea 1022 pktout.maxlen = length + 256;
1023 pktout.data =
1024 (pktout.data ==
1025 NULL ? smalloc(pktout.maxlen +
1026 APIEXTRA) : srealloc(pktout.data,
1027 pktout.maxlen +
1028 APIEXTRA));
1029 if (!pktout.data)
1030 fatalbox("Out of memory");
7cca0d81 1031 }
783415f8 1032}
32874aea 1033static void ssh2_pkt_adddata(void *data, int len)
1034{
783415f8 1035 pktout.length += len;
1036 ssh2_pkt_ensure(pktout.length);
32874aea 1037 memcpy(pktout.data + pktout.length - len, data, len);
7cca0d81 1038}
32874aea 1039static void ssh2_pkt_addbyte(unsigned char byte)
1040{
7cca0d81 1041 ssh2_pkt_adddata(&byte, 1);
1042}
32874aea 1043static void ssh2_pkt_init(int pkt_type)
1044{
7cca0d81 1045 pktout.length = 5;
32874aea 1046 ssh2_pkt_addbyte((unsigned char) pkt_type);
7cca0d81 1047}
32874aea 1048static void ssh2_pkt_addbool(unsigned char value)
1049{
7cca0d81 1050 ssh2_pkt_adddata(&value, 1);
1051}
32874aea 1052static void ssh2_pkt_adduint32(unsigned long value)
1053{
7cca0d81 1054 unsigned char x[4];
1055 PUT_32BIT(x, value);
1056 ssh2_pkt_adddata(x, 4);
1057}
32874aea 1058static void ssh2_pkt_addstring_start(void)
1059{
7cca0d81 1060 ssh2_pkt_adduint32(0);
1061 pktout.savedpos = pktout.length;
1062}
32874aea 1063static void ssh2_pkt_addstring_str(char *data)
1064{
7cca0d81 1065 ssh2_pkt_adddata(data, strlen(data));
1066 PUT_32BIT(pktout.data + pktout.savedpos - 4,
32874aea 1067 pktout.length - pktout.savedpos);
7cca0d81 1068}
32874aea 1069static void ssh2_pkt_addstring_data(char *data, int len)
1070{
7cca0d81 1071 ssh2_pkt_adddata(data, len);
1072 PUT_32BIT(pktout.data + pktout.savedpos - 4,
32874aea 1073 pktout.length - pktout.savedpos);
7cca0d81 1074}
32874aea 1075static void ssh2_pkt_addstring(char *data)
1076{
7cca0d81 1077 ssh2_pkt_addstring_start();
1078 ssh2_pkt_addstring_str(data);
1079}
32874aea 1080static char *ssh2_mpint_fmt(Bignum b, int *len)
1081{
7cca0d81 1082 unsigned char *p;
32874aea 1083 int i, n = (bignum_bitcount(b) + 7) / 8;
3709bfe9 1084 p = smalloc(n + 1);
7cca0d81 1085 if (!p)
32874aea 1086 fatalbox("out of memory");
7cca0d81 1087 p[0] = 0;
3709bfe9 1088 for (i = 1; i <= n; i++)
32874aea 1089 p[i] = bignum_byte(b, n - i);
7cca0d81 1090 i = 0;
32874aea 1091 while (i <= n && p[i] == 0 && (p[i + 1] & 0x80) == 0)
1092 i++;
1093 memmove(p, p + i, n + 1 - i);
1094 *len = n + 1 - i;
7cca0d81 1095 return p;
1096}
32874aea 1097static void ssh2_pkt_addmp(Bignum b)
1098{
7cca0d81 1099 unsigned char *p;
1100 int len;
1101 p = ssh2_mpint_fmt(b, &len);
1102 ssh2_pkt_addstring_start();
1103 ssh2_pkt_addstring_data(p, len);
dcbde236 1104 sfree(p);
7cca0d81 1105}
b185170a 1106
1107/*
1108 * Construct an SSH2 final-form packet: compress it, encrypt it,
1109 * put the MAC on it. Final packet, ready to be sent, is stored in
1110 * pktout.data. Total length is returned.
1111 */
32874aea 1112static int ssh2_pkt_construct(void)
1113{
7cca0d81 1114 int cipherblk, maclen, padding, i;
1115 static unsigned long outgoing_sequence = 0;
1116
1117 /*
4ba9b64b 1118 * Compress packet payload.
1119 */
765c4200 1120#ifdef DUMP_PACKETS
1121 debug(("Pre-compression payload:\n"));
32874aea 1122 dmemdump(pktout.data + 5, pktout.length - 5);
4ba9b64b 1123#endif
1124 {
1125 unsigned char *newpayload;
1126 int newlen;
32874aea 1127 if (cscomp && cscomp->compress(pktout.data + 5, pktout.length - 5,
4ba9b64b 1128 &newpayload, &newlen)) {
1129 pktout.length = 5;
1130 ssh2_pkt_adddata(newpayload, newlen);
dcbde236 1131 sfree(newpayload);
4ba9b64b 1132 }
1133 }
1134
1135 /*
7cca0d81 1136 * Add padding. At least four bytes, and must also bring total
1137 * length (minus MAC) up to a multiple of the block size.
1138 */
32874aea 1139 cipherblk = cscipher ? cscipher->blksize : 8; /* block size */
1140 cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */
7cca0d81 1141 padding = 4;
32874aea 1142 padding +=
1143 (cipherblk - (pktout.length + padding) % cipherblk) % cipherblk;
783415f8 1144 maclen = csmac ? csmac->len : 0;
1145 ssh2_pkt_ensure(pktout.length + padding + maclen);
7cca0d81 1146 pktout.data[4] = padding;
1147 for (i = 0; i < padding; i++)
32874aea 1148 pktout.data[pktout.length + i] = random_byte();
7cca0d81 1149 PUT_32BIT(pktout.data, pktout.length + padding - 4);
1150 if (csmac)
32874aea 1151 csmac->generate(pktout.data, pktout.length + padding,
1152 outgoing_sequence);
1153 outgoing_sequence++; /* whether or not we MACed */
7cca0d81 1154
765c4200 1155#ifdef DUMP_PACKETS
32874aea 1156 debug(("Sending packet len=%d\n", pktout.length + padding));
1157 dmemdump(pktout.data, pktout.length + padding);
7cca0d81 1158#endif
1159
1160 if (cscipher)
32874aea 1161 cscipher->encrypt(pktout.data, pktout.length + padding);
7cca0d81 1162
b185170a 1163 /* Ready-to-send packet starts at pktout.data. We return length. */
1164 return pktout.length + padding + maclen;
1165}
1166
1167/*
1168 * Construct and send an SSH2 packet immediately.
1169 */
32874aea 1170static void ssh2_pkt_send(void)
1171{
b185170a 1172 int len = ssh2_pkt_construct();
1173 sk_write(s, pktout.data, len);
1174}
1175
1176/*
1177 * Construct an SSH2 packet and add it to a deferred data block.
1178 * Useful for sending multiple packets in a single sk_write() call,
1179 * to prevent a traffic-analysing listener from being able to work
1180 * out the length of any particular packet (such as the password
1181 * packet).
1182 *
1183 * Note that because SSH2 sequence-numbers its packets, this can
1184 * NOT be used as an m4-style `defer' allowing packets to be
1185 * constructed in one order and sent in another.
1186 */
32874aea 1187static void ssh2_pkt_defer(void)
1188{
b185170a 1189 int len = ssh2_pkt_construct();
1190 if (deferred_len + len > deferred_size) {
32874aea 1191 deferred_size = deferred_len + len + 128;
1192 deferred_send_data = srealloc(deferred_send_data, deferred_size);
b185170a 1193 }
32874aea 1194 memcpy(deferred_send_data + deferred_len, pktout.data, len);
b185170a 1195 deferred_len += len;
1196}
1197
1198/*
1199 * Send the whole deferred data block constructed by
39065bed 1200 * ssh2_pkt_defer() or SSH1's defer_packet().
b185170a 1201 */
32874aea 1202static void ssh_pkt_defersend(void)
1203{
b185170a 1204 sk_write(s, deferred_send_data, deferred_len);
1205 deferred_len = deferred_size = 0;
1206 sfree(deferred_send_data);
1207 deferred_send_data = NULL;
7cca0d81 1208}
1209
1210#if 0
32874aea 1211void bndebug(char *string, Bignum b)
1212{
7cca0d81 1213 unsigned char *p;
1214 int i, len;
1215 p = ssh2_mpint_fmt(b, &len);
1216 debug(("%s", string));
1217 for (i = 0; i < len; i++)
32874aea 1218 debug((" %02x", p[i]));
765c4200 1219 debug(("\n"));
dcbde236 1220 sfree(p);
7cca0d81 1221}
1222#endif
1223
32874aea 1224static void sha_mpint(SHA_State * s, Bignum b)
1225{
7cca0d81 1226 unsigned char *p;
1227 int len;
1228 p = ssh2_mpint_fmt(b, &len);
1229 sha_string(s, p, len);
dcbde236 1230 sfree(p);
7cca0d81 1231}
1232
1233/*
1234 * SSH2 packet decode functions.
1235 */
32874aea 1236static unsigned long ssh2_pkt_getuint32(void)
1237{
7cca0d81 1238 unsigned long value;
1239 if (pktin.length - pktin.savedpos < 4)
32874aea 1240 return 0; /* arrgh, no way to decline (FIXME?) */
1241 value = GET_32BIT(pktin.data + pktin.savedpos);
7cca0d81 1242 pktin.savedpos += 4;
1243 return value;
1244}
32874aea 1245static int ssh2_pkt_getbool(void)
1246{
65a22376 1247 unsigned long value;
1248 if (pktin.length - pktin.savedpos < 1)
32874aea 1249 return 0; /* arrgh, no way to decline (FIXME?) */
65a22376 1250 value = pktin.data[pktin.savedpos] != 0;
1251 pktin.savedpos++;
1252 return value;
1253}
32874aea 1254static void ssh2_pkt_getstring(char **p, int *length)
1255{
7cca0d81 1256 *p = NULL;
1257 if (pktin.length - pktin.savedpos < 4)
32874aea 1258 return;
1259 *length = GET_32BIT(pktin.data + pktin.savedpos);
7cca0d81 1260 pktin.savedpos += 4;
1261 if (pktin.length - pktin.savedpos < *length)
32874aea 1262 return;
1263 *p = pktin.data + pktin.savedpos;
7cca0d81 1264 pktin.savedpos += *length;
1265}
32874aea 1266static Bignum ssh2_pkt_getmp(void)
1267{
7cca0d81 1268 char *p;
3709bfe9 1269 int length;
7cca0d81 1270 Bignum b;
1271
1272 ssh2_pkt_getstring(&p, &length);
1273 if (!p)
32874aea 1274 return NULL;
8d5de777 1275 if (p[0] & 0x80) {
32874aea 1276 bombout(("internal error: Can't handle negative mpints"));
1277 return NULL;
8d5de777 1278 }
3709bfe9 1279 b = bignum_from_bytes(p, length);
7cca0d81 1280 return b;
1281}
1282
7d503c31 1283/*
1284 * Examine the remote side's version string and compare it against
1285 * a list of known buggy implementations.
1286 */
32874aea 1287static void ssh_detect_bugs(char *vstring)
1288{
1289 char *imp; /* pointer to implementation part */
7d503c31 1290 imp = vstring;
1291 imp += strcspn(imp, "-");
32874aea 1292 if (*imp)
1293 imp++;
7d503c31 1294 imp += strcspn(imp, "-");
32874aea 1295 if (*imp)
1296 imp++;
7d503c31 1297
1298 ssh_remote_bugs = 0;
1299
1300 if (!strcmp(imp, "1.2.18") || !strcmp(imp, "1.2.19") ||
32874aea 1301 !strcmp(imp, "1.2.20") || !strcmp(imp, "1.2.21") ||
1302 !strcmp(imp, "1.2.22")) {
1303 /*
1304 * These versions don't support SSH1_MSG_IGNORE, so we have
1305 * to use a different defence against password length
1306 * sniffing.
1307 */
1308 ssh_remote_bugs |= BUG_CHOKES_ON_SSH1_IGNORE;
1309 logevent("We believe remote version has SSH1 ignore bug");
7d503c31 1310 }
1311
1312 if (!strncmp(imp, "2.1.0", 5) || !strncmp(imp, "2.0.", 4) ||
32874aea 1313 !strncmp(imp, "2.2.0", 5) || !strncmp(imp, "2.3.0", 5) ||
1314 !strncmp(imp, "2.1 ", 4)) {
1315 /*
1316 * These versions have the HMAC bug.
1317 */
1318 ssh_remote_bugs |= BUG_SSH2_HMAC;
1319 logevent("We believe remote version has SSH2 HMAC bug");
7d503c31 1320 }
1321}
1322
32874aea 1323static int do_ssh_init(unsigned char c)
1324{
50526e47 1325 static char vslen;
8df7a775 1326 static char version[10];
50526e47 1327 static char *vstring;
1328 static int vstrsize;
1329 static char *vlog;
8df7a775 1330 static int i;
374330e2 1331
8df7a775 1332 crBegin;
1333
1334 /* Search for the string "SSH-" in the input. */
374330e2 1335 i = 0;
8df7a775 1336 while (1) {
1337 static const int transS[] = { 1, 2, 2, 1 };
1338 static const int transH[] = { 0, 0, 3, 0 };
1339 static const int transminus[] = { 0, 0, 0, -1 };
32874aea 1340 if (c == 'S')
1341 i = transS[i];
1342 else if (c == 'H')
1343 i = transH[i];
1344 else if (c == '-')
1345 i = transminus[i];
1346 else
1347 i = 0;
8df7a775 1348 if (i < 0)
1349 break;
1350 crReturn(1); /* get another character */
374330e2 1351 }
8df7a775 1352
50526e47 1353 vstring = smalloc(16);
1354 vstrsize = 16;
c5e9c988 1355 strcpy(vstring, "SSH-");
50526e47 1356 vslen = 4;
374330e2 1357 i = 0;
1358 while (1) {
8df7a775 1359 crReturn(1); /* get another char */
32874aea 1360 if (vslen >= vstrsize - 1) {
1361 vstrsize += 16;
1362 vstring = srealloc(vstring, vstrsize);
1363 }
1364 vstring[vslen++] = c;
374330e2 1365 if (i >= 0) {
1366 if (c == '-') {
1367 version[i] = '\0';
1368 i = -1;
32874aea 1369 } else if (i < sizeof(version) - 1)
374330e2 1370 version[i++] = c;
32874aea 1371 } else if (c == '\n')
374330e2 1372 break;
1373 }
1374
db7d555c 1375 ssh_agentfwd_enabled = FALSE;
960e736a 1376 rdpkt2_state.incoming_sequence = 0;
1377
50526e47 1378 vstring[vslen] = 0;
9275ca8a 1379 vlog = smalloc(20 + vslen);
c5e9c988 1380 sprintf(vlog, "Server version: %s", vstring);
7d503c31 1381 ssh_detect_bugs(vstring);
c5e9c988 1382 vlog[strcspn(vlog, "\r\n")] = '\0';
1383 logevent(vlog);
9275ca8a 1384 sfree(vlog);
c5e9c988 1385
adf799dd 1386 /*
1387 * Server version "1.99" means we can choose whether we use v1
1388 * or v2 protocol. Choice is based on cfg.sshprot.
1389 */
1390 if (ssh_versioncmp(version, cfg.sshprot == 1 ? "2.0" : "1.99") >= 0) {
32874aea 1391 /*
1392 * This is a v2 server. Begin v2 protocol.
1393 */
1394 char verstring[80], vlog[100];
1395 sprintf(verstring, "SSH-2.0-%s", sshver);
1396 SHA_Init(&exhashbase);
1397 /*
1398 * Hash our version string and their version string.
1399 */
1400 sha_string(&exhashbase, verstring, strlen(verstring));
1401 sha_string(&exhashbase, vstring, strcspn(vstring, "\r\n"));
1402 sprintf(vlog, "We claim version: %s", verstring);
1403 logevent(vlog);
1404 strcat(verstring, "\n");
1405 logevent("Using SSH protocol version 2");
1406 sk_write(s, verstring, strlen(verstring));
1407 ssh_protocol = ssh2_protocol;
1408 ssh_version = 2;
1409 s_rdpkt = ssh2_rdpkt;
e5574168 1410 } else {
32874aea 1411 /*
1412 * This is a v1 server. Begin v1 protocol.
1413 */
1414 char verstring[80], vlog[100];
1415 sprintf(verstring, "SSH-%s-%s",
1416 (ssh_versioncmp(version, "1.5") <= 0 ? version : "1.5"),
1417 sshver);
1418 sprintf(vlog, "We claim version: %s", verstring);
1419 logevent(vlog);
1420 strcat(verstring, "\n");
1421 logevent("Using SSH protocol version 1");
1422 sk_write(s, verstring, strlen(verstring));
1423 ssh_protocol = ssh1_protocol;
1424 ssh_version = 1;
1425 s_rdpkt = ssh1_rdpkt;
e5574168 1426 }
3687d221 1427 ssh_state = SSH_STATE_BEFORE_SIZE;
8df7a775 1428
50526e47 1429 sfree(vstring);
50526e47 1430
8df7a775 1431 crFinish(0);
1432}
1433
1434static void ssh_gotdata(unsigned char *data, int datalen)
1435{
1436 crBegin;
1437
1438 /*
1439 * To begin with, feed the characters one by one to the
1440 * protocol initialisation / selection function do_ssh_init().
1441 * When that returns 0, we're done with the initial greeting
1442 * exchange and can move on to packet discipline.
1443 */
1444 while (1) {
1445 int ret;
1446 if (datalen == 0)
1447 crReturnV; /* more data please */
1448 ret = do_ssh_init(*data);
32874aea 1449 data++;
1450 datalen--;
8df7a775 1451 if (ret == 0)
1452 break;
1453 }
1454
1455 /*
1456 * We emerge from that loop when the initial negotiation is
1457 * over and we have selected an s_rdpkt function. Now pass
1458 * everything to s_rdpkt, and then pass the resulting packets
1459 * to the proper protocol handler.
1460 */
1461 if (datalen == 0)
1462 crReturnV;
1463 while (1) {
1464 while (datalen > 0) {
32874aea 1465 if (s_rdpkt(&data, &datalen) == 0) {
8df7a775 1466 ssh_protocol(NULL, 0, 1);
1467 if (ssh_state == SSH_STATE_CLOSED) {
1468 return;
1469 }
1470 }
1471 }
1472 crReturnV;
1473 }
1474 crFinishV;
1475}
1476
32874aea 1477static int ssh_closing(Plug plug, char *error_msg, int error_code,
1478 int calling_back)
1479{
7e78000d 1480 ssh_state = SSH_STATE_CLOSED;
1481 sk_close(s);
1482 s = NULL;
1483 if (error_msg) {
32874aea 1484 /* A socket error has occurred. */
1485 connection_fatal(error_msg);
7e78000d 1486 } else {
1487 /* Otherwise, the remote side closed the connection normally. */
8df7a775 1488 }
7e78000d 1489 return 0;
1490}
1491
32874aea 1492static int ssh_receive(Plug plug, int urgent, char *data, int len)
1493{
1494 ssh_gotdata(data, len);
3257deae 1495 if (ssh_state == SSH_STATE_CLOSED) {
32874aea 1496 if (s) {
1497 sk_close(s);
1498 s = NULL;
1499 }
1500 return 0;
3257deae 1501 }
fef97f43 1502 return 1;
374330e2 1503}
1504
fb09bf1c 1505/*
8df7a775 1506 * Connect to specified host and port.
1507 * Returns an error message, or NULL on success.
6e1ebb76 1508 * Also places the canonical host name into `realhost'. It must be
1509 * freed by the caller.
8df7a775 1510 */
1511static char *connect_to_host(char *host, int port, char **realhost)
1512{
7e78000d 1513 static struct plug_function_table fn_table = {
1514 ssh_closing,
1515 ssh_receive
1516 }, *fn_table_ptr = &fn_table;
1517
8df7a775 1518 SockAddr addr;
1519 char *err;
1520#ifdef FWHACK
1521 char *FWhost;
1522 int FWport;
1523#endif
1524
32874aea 1525 savedhost = smalloc(1 + strlen(host));
8df7a775 1526 if (!savedhost)
1527 fatalbox("Out of memory");
1528 strcpy(savedhost, host);
1529
1530 if (port < 0)
1531 port = 22; /* default ssh port */
1532 savedport = port;
1533
1534#ifdef FWHACK
1535 FWhost = host;
1536 FWport = port;
1537 host = FWSTR;
1538 port = 23;
1539#endif
1540
1541 /*
1542 * Try to find host.
1543 */
1544 addr = sk_namelookup(host, realhost);
32874aea 1545 if ((err = sk_addr_error(addr)))
8df7a775 1546 return err;
1547
1548#ifdef FWHACK
6e1ebb76 1549 *realhost = strdup(FWhost);
8df7a775 1550#endif
1551
1552 /*
1553 * Open socket.
1554 */
7e78000d 1555 s = sk_new(addr, port, 0, 1, &fn_table_ptr);
32874aea 1556 if ((err = sk_socket_error(s)))
8df7a775 1557 return err;
1558
1559#ifdef FWHACK
1560 sk_write(s, "connect ", 8);
1561 sk_write(s, FWhost, strlen(FWhost));
1562 {
1563 char buf[20];
1564 sprintf(buf, " %d\n", FWport);
1565 sk_write(s, buf, strlen(buf));
1566 }
1567#endif
1568
1569 return NULL;
1570}
1571
1572/*
fb09bf1c 1573 * Handle the key exchange and user authentication phases.
1574 */
e5574168 1575static int do_ssh1_login(unsigned char *in, int inlen, int ispkt)
fb09bf1c 1576{
374330e2 1577 int i, j, len;
374330e2 1578 unsigned char *rsabuf, *keystr1, *keystr2;
1579 unsigned char cookie[8];
1580 struct RSAKey servkey, hostkey;
1581 struct MD5Context md5c;
ccbfb941 1582 static unsigned long supported_ciphers_mask, supported_auths_mask;
7cca0d81 1583 static int tried_publickey;
1584 static unsigned char session_id[16];
bea1ef5f 1585 int cipher_type;
b585ec46 1586 static char username[100];
374330e2 1587
374330e2 1588 crBegin;
1589
32874aea 1590 if (!ispkt)
1591 crWaitUntil(ispkt);
374330e2 1592
8d5de777 1593 if (pktin.type != SSH1_SMSG_PUBLIC_KEY) {
1594 bombout(("Public key packet not received"));
32874aea 1595 crReturn(0);
8d5de777 1596 }
374330e2 1597
c5e9c988 1598 logevent("Received public keys");
374330e2 1599
c5e9c988 1600 memcpy(cookie, pktin.body, 8);
374330e2 1601
32874aea 1602 i = makekey(pktin.body + 8, &servkey, &keystr1, 0);
1603 j = makekey(pktin.body + 8 + i, &hostkey, &keystr2, 0);
374330e2 1604
c5e9c988 1605 /*
1c2a93c4 1606 * Log the host key fingerprint.
c5e9c988 1607 */
c5e9c988 1608 {
1609 char logmsg[80];
1c2a93c4 1610 logevent("Host key fingerprint is:");
c5e9c988 1611 strcpy(logmsg, " ");
32874aea 1612 hostkey.comment = NULL;
1613 rsa_fingerprint(logmsg + strlen(logmsg),
1614 sizeof(logmsg) - strlen(logmsg), &hostkey);
c5e9c988 1615 logevent(logmsg);
1616 }
1617
32874aea 1618 ssh1_remote_protoflags = GET_32BIT(pktin.body + 8 + i + j);
1619 supported_ciphers_mask = GET_32BIT(pktin.body + 12 + i + j);
1620 supported_auths_mask = GET_32BIT(pktin.body + 16 + i + j);
bea1ef5f 1621
32874aea 1622 ssh1_local_protoflags =
1623 ssh1_remote_protoflags & SSH1_PROTOFLAGS_SUPPORTED;
b96dc54c 1624 ssh1_local_protoflags |= SSH1_PROTOFLAG_SCREEN_NUMBER;
1625
c5e9c988 1626 MD5Init(&md5c);
374330e2 1627 MD5Update(&md5c, keystr2, hostkey.bytes);
1628 MD5Update(&md5c, keystr1, servkey.bytes);
1629 MD5Update(&md5c, pktin.body, 8);
374330e2 1630 MD5Final(session_id, &md5c);
1631
32874aea 1632 for (i = 0; i < 32; i++)
374330e2 1633 session_key[i] = random_byte();
1634
1635 len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes);
1636
dcbde236 1637 rsabuf = smalloc(len);
374330e2 1638 if (!rsabuf)
1639 fatalbox("Out of memory");
1640
89ee5268 1641 /*
1642 * Verify the host key.
1643 */
1644 {
32874aea 1645 /*
1646 * First format the key into a string.
1647 */
1648 int len = rsastr_len(&hostkey);
1649 char fingerprint[100];
1650 char *keystr = smalloc(len);
1651 if (!keystr)
1652 fatalbox("Out of memory");
1653 rsastr_fmt(keystr, &hostkey);
1654 rsa_fingerprint(fingerprint, sizeof(fingerprint), &hostkey);
1655 verify_ssh_host_key(savedhost, savedport, "rsa", keystr,
1656 fingerprint);
1657 sfree(keystr);
1658 }
1659
1660 for (i = 0; i < 32; i++) {
374330e2 1661 rsabuf[i] = session_key[i];
1662 if (i < 16)
1663 rsabuf[i] ^= session_id[i];
1664 }
1665
1666 if (hostkey.bytes > servkey.bytes) {
1667 rsaencrypt(rsabuf, 32, &servkey);
1668 rsaencrypt(rsabuf, servkey.bytes, &hostkey);
1669 } else {
1670 rsaencrypt(rsabuf, 32, &hostkey);
1671 rsaencrypt(rsabuf, hostkey.bytes, &servkey);
1672 }
1673
c5e9c988 1674 logevent("Encrypted session key");
1675
0a3f1d48 1676 switch (cfg.cipher) {
32874aea 1677 case CIPHER_BLOWFISH:
1678 cipher_type = SSH_CIPHER_BLOWFISH;
1679 break;
1680 case CIPHER_DES:
1681 cipher_type = SSH_CIPHER_DES;
1682 break;
1683 case CIPHER_3DES:
1684 cipher_type = SSH_CIPHER_3DES;
1685 break;
0a3f1d48 1686 case CIPHER_AES:
32874aea 1687 c_write_str("AES not supported in SSH1, falling back to 3DES\r\n");
1688 cipher_type = SSH_CIPHER_3DES;
1689 break;
0a3f1d48 1690 }
bea1ef5f 1691 if ((supported_ciphers_mask & (1 << cipher_type)) == 0) {
32874aea 1692 c_write_str
1693 ("Selected cipher not supported, falling back to 3DES\r\n");
bea1ef5f 1694 cipher_type = SSH_CIPHER_3DES;
a99a05c0 1695 if ((supported_ciphers_mask & (1 << cipher_type)) == 0) {
1696 bombout(("Server violates SSH 1 protocol by "
1697 "not supporting 3DES encryption"));
1698 crReturn(0);
1699 }
bea1ef5f 1700 }
c5e9c988 1701 switch (cipher_type) {
32874aea 1702 case SSH_CIPHER_3DES:
1703 logevent("Using 3DES encryption");
1704 break;
1705 case SSH_CIPHER_DES:
1706 logevent("Using single-DES encryption");
1707 break;
1708 case SSH_CIPHER_BLOWFISH:
1709 logevent("Using Blowfish encryption");
1710 break;
c5e9c988 1711 }
bea1ef5f 1712
e5574168 1713 send_packet(SSH1_CMSG_SESSION_KEY,
32874aea 1714 PKT_CHAR, cipher_type,
1715 PKT_DATA, cookie, 8,
1716 PKT_CHAR, (len * 8) >> 8, PKT_CHAR, (len * 8) & 0xFF,
1717 PKT_DATA, rsabuf, len,
1718 PKT_INT, ssh1_local_protoflags, PKT_END);
fb09bf1c 1719
c5e9c988 1720 logevent("Trying to enable encryption...");
374330e2 1721
dcbde236 1722 sfree(rsabuf);
374330e2 1723
5e8358ad 1724 cipher = cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 :
32874aea 1725 cipher_type == SSH_CIPHER_DES ? &ssh_des : &ssh_3des;
374330e2 1726 cipher->sesskey(session_key);
1727
fb09bf1c 1728 crWaitUntil(ispkt);
374330e2 1729
8d5de777 1730 if (pktin.type != SSH1_SMSG_SUCCESS) {
1731 bombout(("Encryption not successfully enabled"));
32874aea 1732 crReturn(0);
8d5de777 1733 }
374330e2 1734
c5e9c988 1735 logevent("Successfully started encryption");
1736
374330e2 1737 fflush(stdout);
1738 {
374330e2 1739 static int pos = 0;
1740 static char c;
67779be7 1741 if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
32874aea 1742 if (ssh_get_line) {
1743 if (!ssh_get_line("login as: ",
1744 username, sizeof(username), FALSE)) {
1745 /*
1746 * get_line failed to get a username.
1747 * Terminate.
1748 */
1749 logevent("No username provided. Abandoning session.");
1750 ssh_state = SSH_STATE_CLOSED;
1751 crReturn(1);
1752 }
1753 } else {
1754 c_write_str("login as: ");
1755 ssh_send_ok = 1;
1756 while (pos >= 0) {
1757 crWaitUntil(!ispkt);
1758 while (inlen--)
1759 switch (c = *in++) {
1760 case 10:
1761 case 13:
1762 username[pos] = 0;
1763 pos = -1;
1764 break;
1765 case 8:
1766 case 127:
1767 if (pos > 0) {
1768 c_write_str("\b \b");
1769 pos--;
1770 }
1771 break;
1772 case 21:
1773 case 27:
1774 while (pos > 0) {
1775 c_write_str("\b \b");
1776 pos--;
1777 }
1778 break;
1779 case 3:
1780 case 4:
1781 random_save_seed();
1782 exit(0);
1783 break;
1784 default:
1785 if (((c >= ' ' && c <= '~') ||
51b2fb65 1786 ((unsigned char) c >= 160))
1787 && pos < sizeof(username)-1) {
32874aea 1788 username[pos++] = c;
1789 c_write(&c, 1);
1790 }
1791 break;
1792 }
1793 }
1794 c_write_str("\r\n");
1795 username[strcspn(username, "\n\r")] = '\0';
1796 }
1797 } else {
374330e2 1798 strncpy(username, cfg.username, 99);
1799 username[99] = '\0';
374330e2 1800 }
fb09bf1c 1801
e5574168 1802 send_packet(SSH1_CMSG_USER, PKT_STR, username, PKT_END);
c5e9c988 1803 {
32874aea 1804 char userlog[22 + sizeof(username)];
c5e9c988 1805 sprintf(userlog, "Sent username \"%s\"", username);
1806 logevent(userlog);
32874aea 1807 if (flags & FLAG_INTERACTIVE &&
1808 (!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) {
3c8e959b 1809 strcat(userlog, "\r\n");
32874aea 1810 c_write_str(userlog);
3c8e959b 1811 }
c5e9c988 1812 }
374330e2 1813 }
1814
fb09bf1c 1815 crWaitUntil(ispkt);
374330e2 1816
7cca0d81 1817 tried_publickey = 0;
1818
e5574168 1819 while (pktin.type == SSH1_SMSG_FAILURE) {
374330e2 1820 static char password[100];
a52f067e 1821 static char prompt[200];
374330e2 1822 static int pos;
1823 static char c;
32874aea 1824 static int pwpkt_type;
1825 /*
1826 * Show password prompt, having first obtained it via a TIS
1827 * or CryptoCard exchange if we're doing TIS or CryptoCard
1828 * authentication.
1829 */
1830 pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
1831 if (agent_exists()) {
1832 /*
1833 * Attempt RSA authentication using Pageant.
1834 */
1835 static unsigned char request[5], *response, *p;
1836 static int responselen;
1837 static int i, nkeys;
1838 static int authed = FALSE;
1839 void *r;
1840
1841 logevent("Pageant is running. Requesting keys.");
1842
1843 /* Request the keys held by the agent. */
1844 PUT_32BIT(request, 1);
1845 request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES;
1846 agent_query(request, 5, &r, &responselen);
1847 response = (unsigned char *) r;
1848 if (response && responselen >= 5 &&
1849 response[4] == SSH1_AGENT_RSA_IDENTITIES_ANSWER) {
1850 p = response + 5;
1851 nkeys = GET_32BIT(p);
1852 p += 4;
1853 {
1854 char buf[64];
1855 sprintf(buf, "Pageant has %d SSH1 keys", nkeys);
1856 logevent(buf);
1857 }
1858 for (i = 0; i < nkeys; i++) {
1859 static struct RSAKey key;
1860 static Bignum challenge;
1861 static char *commentp;
1862 static int commentlen;
1863
1864 {
1865 char buf[64];
1866 sprintf(buf, "Trying Pageant key #%d", i);
1867 logevent(buf);
1868 }
1869 p += 4;
1870 p += ssh1_read_bignum(p, &key.exponent);
1871 p += ssh1_read_bignum(p, &key.modulus);
1872 commentlen = GET_32BIT(p);
1873 p += 4;
1874 commentp = p;
1875 p += commentlen;
1876 send_packet(SSH1_CMSG_AUTH_RSA,
1877 PKT_BIGNUM, key.modulus, PKT_END);
1878 crWaitUntil(ispkt);
1879 if (pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
1880 logevent("Key refused");
1881 continue;
1882 }
1883 logevent("Received RSA challenge");
1884 ssh1_read_bignum(pktin.body, &challenge);
1885 {
1886 char *agentreq, *q, *ret;
1887 int len, retlen;
1888 len = 1 + 4; /* message type, bit count */
1889 len += ssh1_bignum_length(key.exponent);
1890 len += ssh1_bignum_length(key.modulus);
1891 len += ssh1_bignum_length(challenge);
1892 len += 16; /* session id */
1893 len += 4; /* response format */
1894 agentreq = smalloc(4 + len);
1895 PUT_32BIT(agentreq, len);
1896 q = agentreq + 4;
1897 *q++ = SSH1_AGENTC_RSA_CHALLENGE;
1898 PUT_32BIT(q, bignum_bitcount(key.modulus));
1899 q += 4;
1900 q += ssh1_write_bignum(q, key.exponent);
1901 q += ssh1_write_bignum(q, key.modulus);
1902 q += ssh1_write_bignum(q, challenge);
1903 memcpy(q, session_id, 16);
1904 q += 16;
1905 PUT_32BIT(q, 1); /* response format */
1906 agent_query(agentreq, len + 4, &ret, &retlen);
1907 sfree(agentreq);
1908 if (ret) {
1909 if (ret[4] == SSH1_AGENT_RSA_RESPONSE) {
1910 logevent("Sending Pageant's response");
1911 send_packet(SSH1_CMSG_AUTH_RSA_RESPONSE,
1912 PKT_DATA, ret + 5, 16,
1913 PKT_END);
1914 sfree(ret);
1915 crWaitUntil(ispkt);
1916 if (pktin.type == SSH1_SMSG_SUCCESS) {
1917 logevent
1918 ("Pageant's response accepted");
1919 if (flags & FLAG_VERBOSE) {
1920 c_write_str
1921 ("Authenticated using RSA key \"");
1922 c_write(commentp, commentlen);
1923 c_write_str("\" from agent\r\n");
1924 }
1925 authed = TRUE;
1926 } else
1927 logevent
1928 ("Pageant's response not accepted");
1929 } else {
1930 logevent
1931 ("Pageant failed to answer challenge");
1932 sfree(ret);
1933 }
1934 } else {
1935 logevent("No reply received from Pageant");
1936 }
1937 }
1938 freebn(key.exponent);
1939 freebn(key.modulus);
1940 freebn(challenge);
1941 if (authed)
1942 break;
1943 }
1944 }
1945 if (authed)
1946 break;
1947 }
1948 if (*cfg.keyfile && !tried_publickey)
1949 pwpkt_type = SSH1_CMSG_AUTH_RSA;
1950
1951 if (pktin.type == SSH1_SMSG_FAILURE &&
1952 cfg.try_tis_auth &&
1953 (supported_auths_mask & (1 << SSH1_AUTH_TIS))) {
1954 pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
1955 logevent("Requested TIS authentication");
1956 send_packet(SSH1_CMSG_AUTH_TIS, PKT_END);
1957 crWaitUntil(ispkt);
1958 if (pktin.type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
1959 logevent("TIS authentication declined");
1960 if (flags & FLAG_INTERACTIVE)
1961 c_write_str("TIS authentication refused.\r\n");
1962 } else {
1963 int challengelen = ((pktin.body[0] << 24) |
1964 (pktin.body[1] << 16) |
1965 (pktin.body[2] << 8) |
1966 (pktin.body[3]));
1967 logevent("Received TIS challenge");
1968 if (challengelen > sizeof(prompt) - 1)
1969 challengelen = sizeof(prompt) - 1; /* prevent overrun */
1970 memcpy(prompt, pktin.body + 4, challengelen);
1971 prompt[challengelen] = '\0';
1972 }
1973 }
1974 if (pktin.type == SSH1_SMSG_FAILURE &&
1975 cfg.try_tis_auth &&
1976 (supported_auths_mask & (1 << SSH1_AUTH_CCARD))) {
1977 pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE;
1978 logevent("Requested CryptoCard authentication");
1979 send_packet(SSH1_CMSG_AUTH_CCARD, PKT_END);
1980 crWaitUntil(ispkt);
1981 if (pktin.type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
1982 logevent("CryptoCard authentication declined");
1983 c_write_str("CryptoCard authentication refused.\r\n");
1984 } else {
1985 int challengelen = ((pktin.body[0] << 24) |
1986 (pktin.body[1] << 16) |
1987 (pktin.body[2] << 8) |
1988 (pktin.body[3]));
1989 logevent("Received CryptoCard challenge");
1990 if (challengelen > sizeof(prompt) - 1)
1991 challengelen = sizeof(prompt) - 1; /* prevent overrun */
1992 memcpy(prompt, pktin.body + 4, challengelen);
1993 strncpy(prompt + challengelen, "\r\nResponse : ",
1994 sizeof(prompt) - challengelen);
1995 prompt[sizeof(prompt) - 1] = '\0';
1996 }
1997 }
1998 if (pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
1999 sprintf(prompt, "%.90s@%.90s's password: ",
2000 username, savedhost);
2001 }
2002 if (pwpkt_type == SSH1_CMSG_AUTH_RSA) {
2003 char *comment = NULL;
2004 if (flags & FLAG_VERBOSE)
2005 c_write_str("Trying public key authentication.\r\n");
2006 if (!rsakey_encrypted(cfg.keyfile, &comment)) {
2007 if (flags & FLAG_VERBOSE)
2008 c_write_str("No passphrase required.\r\n");
2009 goto tryauth;
2010 }
2011 sprintf(prompt, "Passphrase for key \"%.100s\": ", comment);
2012 sfree(comment);
2013 }
a52f067e 2014
fa17a66e 2015 if (ssh_get_line) {
2016 if (!ssh_get_line(prompt, password, sizeof(password), TRUE)) {
32874aea 2017 /*
2018 * get_line failed to get a password (for example
2019 * because one was supplied on the command line
2020 * which has already failed to work). Terminate.
2021 */
2bc6a386 2022 send_packet(SSH1_MSG_DISCONNECT,
2023 PKT_STR, "No more passwords available to try",
2024 PKT_END);
2025 connection_fatal("Unable to authenticate");
32874aea 2026 ssh_state = SSH_STATE_CLOSED;
2027 crReturn(1);
2028 }
fb09bf1c 2029 } else {
32874aea 2030 c_write_str(prompt);
2031 pos = 0;
2032 ssh_send_ok = 1;
2033 while (pos >= 0) {
2034 crWaitUntil(!ispkt);
2035 while (inlen--)
2036 switch (c = *in++) {
2037 case 10:
2038 case 13:
2039 password[pos] = 0;
2040 pos = -1;
2041 break;
2042 case 8:
2043 case 127:
2044 if (pos > 0)
2045 pos--;
2046 break;
2047 case 21:
2048 case 27:
2049 pos = 0;
2050 break;
2051 case 3:
2052 case 4:
2053 random_save_seed();
2054 exit(0);
2055 break;
2056 default:
51b2fb65 2057 if (pos < sizeof(password)-1)
32874aea 2058 password[pos++] = c;
2059 break;
2060 }
2061 }
2062 c_write_str("\r\n");
2063 }
2064
2065 tryauth:
7cca0d81 2066 if (pwpkt_type == SSH1_CMSG_AUTH_RSA) {
32874aea 2067 /*
2068 * Try public key authentication with the specified
2069 * key file.
2070 */
2071 static struct RSAKey pubkey;
2072 static Bignum challenge, response;
2073 static int i;
2074 static unsigned char buffer[32];
2075
2076 tried_publickey = 1;
2077 i = loadrsakey(cfg.keyfile, &pubkey, password);
2078 if (i == 0) {
2079 c_write_str("Couldn't load public key from ");
2080 c_write_str(cfg.keyfile);
2081 c_write_str(".\r\n");
2082 continue; /* go and try password */
2083 }
2084 if (i == -1) {
2085 c_write_str("Wrong passphrase.\r\n");
2086 tried_publickey = 0;
2087 continue; /* try again */
2088 }
2089
2090 /*
2091 * Send a public key attempt.
2092 */
2093 send_packet(SSH1_CMSG_AUTH_RSA,
2094 PKT_BIGNUM, pubkey.modulus, PKT_END);
2095
2096 crWaitUntil(ispkt);
2097 if (pktin.type == SSH1_SMSG_FAILURE) {
2098 c_write_str("Server refused our public key.\r\n");
2099 continue; /* go and try password */
2100 }
2101 if (pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
2102 bombout(("Bizarre response to offer of public key"));
2103 crReturn(0);
2104 }
2105 ssh1_read_bignum(pktin.body, &challenge);
2106 response = rsadecrypt(challenge, &pubkey);
2107 freebn(pubkey.private_exponent); /* burn the evidence */
2108
2109 for (i = 0; i < 32; i++) {
2110 buffer[i] = bignum_byte(response, 31 - i);
2111 }
2112
2113 MD5Init(&md5c);
2114 MD5Update(&md5c, buffer, 32);
2115 MD5Update(&md5c, session_id, 16);
2116 MD5Final(buffer, &md5c);
2117
2118 send_packet(SSH1_CMSG_AUTH_RSA_RESPONSE,
2119 PKT_DATA, buffer, 16, PKT_END);
2120
2121 crWaitUntil(ispkt);
2122 if (pktin.type == SSH1_SMSG_FAILURE) {
2123 if (flags & FLAG_VERBOSE)
2124 c_write_str
2125 ("Failed to authenticate with our public key.\r\n");
2126 continue; /* go and try password */
2127 } else if (pktin.type != SSH1_SMSG_SUCCESS) {
2128 bombout(
2129 ("Bizarre response to RSA authentication response"));
2130 crReturn(0);
2131 }
2132
2133 break; /* we're through! */
2134 } else {
2135 if (pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
2136 /*
2137 * Defence against traffic analysis: we send a
2138 * whole bunch of packets containing strings of
2139 * different lengths. One of these strings is the
2140 * password, in a SSH1_CMSG_AUTH_PASSWORD packet.
2141 * The others are all random data in
2142 * SSH1_MSG_IGNORE packets. This way a passive
2143 * listener can't tell which is the password, and
2144 * hence can't deduce the password length.
2145 *
2146 * Anybody with a password length greater than 16
2147 * bytes is going to have enough entropy in their
2148 * password that a listener won't find it _that_
2149 * much help to know how long it is. So what we'll
2150 * do is:
2151 *
2152 * - if password length < 16, we send 15 packets
2153 * containing string lengths 1 through 15
2154 *
2155 * - otherwise, we let N be the nearest multiple
2156 * of 8 below the password length, and send 8
2157 * packets containing string lengths N through
2158 * N+7. This won't obscure the order of
2159 * magnitude of the password length, but it will
2160 * introduce a bit of extra uncertainty.
2161 *
2162 * A few servers (the old 1.2.18 through 1.2.22)
2163 * can't deal with SSH1_MSG_IGNORE. For these
2164 * servers, we need an alternative defence. We make
2165 * use of the fact that the password is interpreted
2166 * as a C string: so we can append a NUL, then some
2167 * random data.
2168 */
2169 if (ssh_remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE) {
2170 char string[64];
2171 char *s;
2172 int len;
2173
2174 len = strlen(password);
2175 if (len < sizeof(string)) {
2176 s = string;
2177 strcpy(string, password);
2178 len++; /* cover the zero byte */
2179 while (len < sizeof(string)) {
2180 string[len++] = (char) random_byte();
2181 }
2182 } else {
2183 s = password;
2184 }
2185 send_packet(pwpkt_type, PKT_INT, len,
2186 PKT_DATA, s, len, PKT_END);
2187 } else {
2188 int bottom, top, pwlen, i;
2189 char *randomstr;
2190
2191 pwlen = strlen(password);
2192 if (pwlen < 16) {
2193 bottom = 0; /* zero length passwords are OK! :-) */
2194 top = 15;
2195 } else {
2196 bottom = pwlen & ~7;
2197 top = bottom + 7;
2198 }
2199
2200 assert(pwlen >= bottom && pwlen <= top);
2201
2202 randomstr = smalloc(top + 1);
2203
2204 for (i = bottom; i <= top; i++) {
2205 if (i == pwlen)
2206 defer_packet(pwpkt_type, PKT_STR, password,
2207 PKT_END);
2208 else {
2209 for (j = 0; j < i; j++) {
2210 do {
2211 randomstr[j] = random_byte();
2212 } while (randomstr[j] == '\0');
2213 }
2214 randomstr[i] = '\0';
2215 defer_packet(SSH1_MSG_IGNORE,
2216 PKT_STR, randomstr, PKT_END);
2217 }
2218 }
2219 ssh_pkt_defersend();
2220 }
2221 } else {
2222 send_packet(pwpkt_type, PKT_STR, password, PKT_END);
2223 }
2224 }
c5e9c988 2225 logevent("Sent password");
374330e2 2226 memset(password, 0, strlen(password));
fb09bf1c 2227 crWaitUntil(ispkt);
e5574168 2228 if (pktin.type == SSH1_SMSG_FAILURE) {
32874aea 2229 if (flags & FLAG_VERBOSE)
2230 c_write_str("Access denied\r\n");
c5e9c988 2231 logevent("Authentication refused");
e5574168 2232 } else if (pktin.type == SSH1_MSG_DISCONNECT) {
fb09bf1c 2233 logevent("Received disconnect request");
32874aea 2234 ssh_state = SSH_STATE_CLOSED;
85ee8208 2235 crReturn(1);
e5574168 2236 } else if (pktin.type != SSH1_SMSG_SUCCESS) {
8d5de777 2237 bombout(("Strange packet received, type %d", pktin.type));
32874aea 2238 crReturn(0);
374330e2 2239 }
2240 }
2241
c5e9c988 2242 logevent("Authentication successful");
2243
fb09bf1c 2244 crFinish(1);
2245}
2246
32874aea 2247void sshfwd_close(struct ssh_channel *c)
2248{
80e48603 2249 if (c && !c->closes) {
32874aea 2250 if (ssh_version == 1) {
2251 send_packet(SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid,
2252 PKT_END);
2253 } else {
2254 ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE);
2255 ssh2_pkt_adduint32(c->remoteid);
2256 ssh2_pkt_send();
2257 }
2258 c->closes = 1;
2259 if (c->type == CHAN_X11) {
2260 c->u.x11.s = NULL;
2261 logevent("X11 connection terminated");
2262 }
2263 }
2264}
2265
2266void sshfwd_write(struct ssh_channel *c, char *buf, int len)
2267{
783415f8 2268 if (ssh_version == 1) {
32874aea 2269 send_packet(SSH1_MSG_CHANNEL_DATA,
2270 PKT_INT, c->remoteid,
2271 PKT_INT, len, PKT_DATA, buf, len, PKT_END);
783415f8 2272 } else {
32874aea 2273 ssh2_add_channel_data(c, buf, len);
2274 ssh2_try_send(c);
783415f8 2275 }
9c964e85 2276}
2277
32874aea 2278static void ssh1_protocol(unsigned char *in, int inlen, int ispkt)
2279{
fb09bf1c 2280 crBegin;
2281
2282 random_init();
2283
e5574168 2284 while (!do_ssh1_login(in, inlen, ispkt)) {
fb09bf1c 2285 crReturnV;
85ee8208 2286 }
2287 if (ssh_state == SSH_STATE_CLOSED)
32874aea 2288 crReturnV;
fb09bf1c 2289
979310f1 2290 if (cfg.agentfwd && agent_exists()) {
32874aea 2291 logevent("Requesting agent forwarding");
2292 send_packet(SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END);
2293 do {
2294 crReturnV;
2295 } while (!ispkt);
2296 if (pktin.type != SSH1_SMSG_SUCCESS
2297 && pktin.type != SSH1_SMSG_FAILURE) {
2298 bombout(("Protocol confusion"));
2299 crReturnV;
2300 } else if (pktin.type == SSH1_SMSG_FAILURE) {
2301 logevent("Agent forwarding refused");
2302 } else {
2303 logevent("Agent forwarding enabled");
db7d555c 2304 ssh_agentfwd_enabled = TRUE;
2305 }
dacbd0e8 2306 }
2307
9c964e85 2308 if (cfg.x11_forward) {
32874aea 2309 char proto[20], data[64];
2310 logevent("Requesting X11 forwarding");
2311 x11_invent_auth(proto, sizeof(proto), data, sizeof(data));
2312 if (ssh1_local_protoflags & SSH1_PROTOFLAG_SCREEN_NUMBER) {
2313 send_packet(SSH1_CMSG_X11_REQUEST_FORWARDING,
2314 PKT_STR, proto, PKT_STR, data,
2315 PKT_INT, 0, PKT_END);
2316 } else {
2317 send_packet(SSH1_CMSG_X11_REQUEST_FORWARDING,
2318 PKT_STR, proto, PKT_STR, data, PKT_END);
2319 }
2320 do {
2321 crReturnV;
2322 } while (!ispkt);
2323 if (pktin.type != SSH1_SMSG_SUCCESS
2324 && pktin.type != SSH1_SMSG_FAILURE) {
2325 bombout(("Protocol confusion"));
2326 crReturnV;
2327 } else if (pktin.type == SSH1_SMSG_FAILURE) {
2328 logevent("X11 forwarding refused");
2329 } else {
2330 logevent("X11 forwarding enabled");
9c964e85 2331 ssh_X11_fwd_enabled = TRUE;
2332 }
2333 }
2334
fef97f43 2335 if (!cfg.nopty) {
e5574168 2336 send_packet(SSH1_CMSG_REQUEST_PTY,
32874aea 2337 PKT_STR, cfg.termtype,
2338 PKT_INT, rows, PKT_INT, cols,
2339 PKT_INT, 0, PKT_INT, 0, PKT_CHAR, 0, PKT_END);
2340 ssh_state = SSH_STATE_INTERMED;
2341 do {
2342 crReturnV;
2343 } while (!ispkt);
2344 if (pktin.type != SSH1_SMSG_SUCCESS
2345 && pktin.type != SSH1_SMSG_FAILURE) {
2346 bombout(("Protocol confusion"));
2347 crReturnV;
2348 } else if (pktin.type == SSH1_SMSG_FAILURE) {
2349 c_write_str("Server refused to allocate pty\r\n");
2350 ssh_editing = ssh_echoing = 1;
2351 }
c5e9c988 2352 logevent("Allocated pty");
0965bee0 2353 } else {
32874aea 2354 ssh_editing = ssh_echoing = 1;
374330e2 2355 }
2356
4ba9b64b 2357 if (cfg.compression) {
32874aea 2358 send_packet(SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END);
2359 do {
2360 crReturnV;
2361 } while (!ispkt);
2362 if (pktin.type != SSH1_SMSG_SUCCESS
2363 && pktin.type != SSH1_SMSG_FAILURE) {
2364 bombout(("Protocol confusion"));
2365 crReturnV;
2366 } else if (pktin.type == SSH1_SMSG_FAILURE) {
2367 c_write_str("Server refused to compress\r\n");
2368 }
4ba9b64b 2369 logevent("Started compression");
2370 ssh1_compressing = TRUE;
2371 zlib_compress_init();
2372 zlib_decompress_init();
2373 }
2374
96621a84 2375 if (*cfg.remote_cmd_ptr)
32874aea 2376 send_packet(SSH1_CMSG_EXEC_CMD, PKT_STR, cfg.remote_cmd_ptr,
2377 PKT_END);
6abbf9e3 2378 else
32874aea 2379 send_packet(SSH1_CMSG_EXEC_SHELL, PKT_END);
c5e9c988 2380 logevent("Started session");
374330e2 2381
2382 ssh_state = SSH_STATE_SESSION;
2383 if (size_needed)
2384 ssh_size();
3687d221 2385 if (eof_needed)
32874aea 2386 ssh_special(TS_EOF);
374330e2 2387
32874aea 2388 ldisc_send(NULL, 0); /* cause ldisc to notice changes */
8ccc75b0 2389 ssh_send_ok = 1;
dacbd0e8 2390 ssh_channels = newtree234(ssh_channelcmp);
374330e2 2391 while (1) {
2392 crReturnV;
2393 if (ispkt) {
e5574168 2394 if (pktin.type == SSH1_SMSG_STDOUT_DATA ||
32874aea 2395 pktin.type == SSH1_SMSG_STDERR_DATA) {
fb09bf1c 2396 long len = GET_32BIT(pktin.body);
fe50e814 2397 from_backend(pktin.type == SSH1_SMSG_STDERR_DATA,
32874aea 2398 pktin.body + 4, len);
e5574168 2399 } else if (pktin.type == SSH1_MSG_DISCONNECT) {
32874aea 2400 ssh_state = SSH_STATE_CLOSED;
c5e9c988 2401 logevent("Received disconnect request");
32874aea 2402 crReturnV;
2403 } else if (pktin.type == SSH1_SMSG_X11_OPEN) {
2404 /* Remote side is trying to open a channel to talk to our
2405 * X-Server. Give them back a local channel number. */
2406 struct ssh_channel *c;
9c964e85 2407
2408 logevent("Received X11 connect request");
2409 /* Refuse if X11 forwarding is disabled. */
2410 if (!ssh_X11_fwd_enabled) {
2411 send_packet(SSH1_MSG_CHANNEL_OPEN_FAILURE,
32874aea 2412 PKT_INT, GET_32BIT(pktin.body), PKT_END);
9c964e85 2413 logevent("Rejected X11 connect request");
2414 } else {
9c964e85 2415 c = smalloc(sizeof(struct ssh_channel));
2416
32874aea 2417 if (x11_init(&c->u.x11.s, cfg.x11_display, c) != NULL) {
2418 logevent("opening X11 forward connection failed");
2419 sfree(c);
2420 send_packet(SSH1_MSG_CHANNEL_OPEN_FAILURE,
2421 PKT_INT, GET_32BIT(pktin.body),
2422 PKT_END);
9c964e85 2423 } else {
32874aea 2424 logevent
2425 ("opening X11 forward connection succeeded");
2426 c->remoteid = GET_32BIT(pktin.body);
2427 c->localid = alloc_channel_id();
2428 c->closes = 0;
2429 c->type = CHAN_X11; /* identify channel type */
2430 add234(ssh_channels, c);
2431 send_packet(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
2432 PKT_INT, c->remoteid, PKT_INT,
2433 c->localid, PKT_END);
2434 logevent("Opened X11 forward channel");
9c964e85 2435 }
2436 }
32874aea 2437 } else if (pktin.type == SSH1_SMSG_AGENT_OPEN) {
2438 /* Remote side is trying to open a channel to talk to our
2439 * agent. Give them back a local channel number. */
2440 struct ssh_channel *c;
db7d555c 2441
2442 /* Refuse if agent forwarding is disabled. */
2443 if (!ssh_agentfwd_enabled) {
2444 send_packet(SSH1_MSG_CHANNEL_OPEN_FAILURE,
32874aea 2445 PKT_INT, GET_32BIT(pktin.body), PKT_END);
db7d555c 2446 } else {
dcbde236 2447 c = smalloc(sizeof(struct ssh_channel));
db7d555c 2448 c->remoteid = GET_32BIT(pktin.body);
d2371c81 2449 c->localid = alloc_channel_id();
db7d555c 2450 c->closes = 0;
32874aea 2451 c->type = CHAN_AGENT; /* identify channel type */
db7d555c 2452 c->u.a.lensofar = 0;
2453 add234(ssh_channels, c);
2454 send_packet(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
2455 PKT_INT, c->remoteid, PKT_INT, c->localid,
2456 PKT_END);
2457 }
2458 } else if (pktin.type == SSH1_MSG_CHANNEL_CLOSE ||
2459 pktin.type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION) {
32874aea 2460 /* Remote side closes a channel. */
2461 unsigned i = GET_32BIT(pktin.body);
2462 struct ssh_channel *c;
2463 c = find234(ssh_channels, &i, ssh_channelfind);
2464 if (c) {
2465 int closetype;
2466 closetype =
2467 (pktin.type == SSH1_MSG_CHANNEL_CLOSE ? 1 : 2);
2468 if (!(c->closes & closetype))
2469 send_packet(pktin.type, PKT_INT, c->remoteid,
2470 PKT_END);
783415f8 2471 if ((c->closes == 0) && (c->type == CHAN_X11)) {
32874aea 2472 logevent("X11 connection closed");
9c964e85 2473 assert(c->u.x11.s != NULL);
2474 x11_close(c->u.x11.s);
2475 c->u.x11.s = NULL;
2476 }
32874aea 2477 c->closes |= closetype;
2478 if (c->closes == 3) {
2479 del234(ssh_channels, c);
2480 sfree(c);
2481 }
2482 }
2483 } else if (pktin.type == SSH1_MSG_CHANNEL_DATA) {
2484 /* Data sent down one of our channels. */
2485 int i = GET_32BIT(pktin.body);
2486 int len = GET_32BIT(pktin.body + 4);
2487 unsigned char *p = pktin.body + 8;
2488 struct ssh_channel *c;
2489 c = find234(ssh_channels, &i, ssh_channelfind);
2490 if (c) {
2491 switch (c->type) {
2492 case CHAN_X11:
9c964e85 2493 x11_send(c->u.x11.s, p, len);
2494 break;
32874aea 2495 case CHAN_AGENT:
2496 /* Data for an agent message. Buffer it. */
2497 while (len > 0) {
2498 if (c->u.a.lensofar < 4) {
2499 int l = min(4 - c->u.a.lensofar, len);
2500 memcpy(c->u.a.msglen + c->u.a.lensofar, p,
2501 l);
2502 p += l;
2503 len -= l;
2504 c->u.a.lensofar += l;
2505 }
2506 if (c->u.a.lensofar == 4) {
2507 c->u.a.totallen =
2508 4 + GET_32BIT(c->u.a.msglen);
2509 c->u.a.message = smalloc(c->u.a.totallen);
2510 memcpy(c->u.a.message, c->u.a.msglen, 4);
2511 }
2512 if (c->u.a.lensofar >= 4 && len > 0) {
2513 int l =
2514 min(c->u.a.totallen - c->u.a.lensofar,
2515 len);
2516 memcpy(c->u.a.message + c->u.a.lensofar, p,
2517 l);
2518 p += l;
2519 len -= l;
2520 c->u.a.lensofar += l;
2521 }
2522 if (c->u.a.lensofar == c->u.a.totallen) {
2523 void *reply, *sentreply;
2524 int replylen;
2525 agent_query(c->u.a.message,
2526 c->u.a.totallen, &reply,
2527 &replylen);
2528 if (reply)
2529 sentreply = reply;
2530 else {
2531 /* Fake SSH_AGENT_FAILURE. */
2532 sentreply = "\0\0\0\1\5";
2533 replylen = 5;
2534 }
2535 send_packet(SSH1_MSG_CHANNEL_DATA,
2536 PKT_INT, c->remoteid,
2537 PKT_INT, replylen,
2538 PKT_DATA, sentreply, replylen,
2539 PKT_END);
2540 if (reply)
2541 sfree(reply);
2542 sfree(c->u.a.message);
2543 c->u.a.lensofar = 0;
2544 }
2545 }
2546 break;
2547 }
2548 }
e5574168 2549 } else if (pktin.type == SSH1_SMSG_SUCCESS) {
972a41c8 2550 /* may be from EXEC_SHELL on some servers */
e5574168 2551 } else if (pktin.type == SSH1_SMSG_FAILURE) {
972a41c8 2552 /* may be from EXEC_SHELL on some servers
374330e2 2553 * if no pty is available or in other odd cases. Ignore */
e5574168 2554 } else if (pktin.type == SSH1_SMSG_EXIT_STATUS) {
2555 send_packet(SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
374330e2 2556 } else {
8d5de777 2557 bombout(("Strange packet received: type %d", pktin.type));
32874aea 2558 crReturnV;
374330e2 2559 }
2560 } else {
8df7a775 2561 while (inlen > 0) {
2562 int len = min(inlen, 512);
2563 send_packet(SSH1_CMSG_STDIN_DATA,
2564 PKT_INT, len, PKT_DATA, in, len, PKT_END);
2565 in += len;
2566 inlen -= len;
2567 }
374330e2 2568 }
2569 }
2570
2571 crFinishV;
2572}
2573
2574/*
e5574168 2575 * Utility routine for decoding comma-separated strings in KEXINIT.
2576 */
32874aea 2577static int in_commasep_string(char *needle, char *haystack, int haylen)
2578{
e5574168 2579 int needlen = strlen(needle);
2580 while (1) {
32874aea 2581 /*
2582 * Is it at the start of the string?
2583 */
2584 if (haylen >= needlen && /* haystack is long enough */
2585 !memcmp(needle, haystack, needlen) && /* initial match */
2586 (haylen == needlen || haystack[needlen] == ',')
2587 /* either , or EOS follows */
2588 )
2589 return 1;
2590 /*
2591 * If not, search for the next comma and resume after that.
2592 * If no comma found, terminate.
2593 */
2594 while (haylen > 0 && *haystack != ',')
2595 haylen--, haystack++;
2596 if (haylen == 0)
2597 return 0;
2598 haylen--, haystack++; /* skip over comma itself */
e5574168 2599 }
2600}
2601
2602/*
d39f364a 2603 * SSH2 key creation method.
2604 */
32874aea 2605static void ssh2_mkkey(Bignum K, char *H, char *sessid, char chr,
2606 char *keyspace)
2607{
d39f364a 2608 SHA_State s;
2609 /* First 20 bytes. */
2610 SHA_Init(&s);
2611 sha_mpint(&s, K);
2612 SHA_Bytes(&s, H, 20);
2613 SHA_Bytes(&s, &chr, 1);
5e0d7cb8 2614 SHA_Bytes(&s, sessid, 20);
d39f364a 2615 SHA_Final(&s, keyspace);
2616 /* Next 20 bytes. */
2617 SHA_Init(&s);
2618 sha_mpint(&s, K);
2619 SHA_Bytes(&s, H, 20);
2620 SHA_Bytes(&s, keyspace, 20);
32874aea 2621 SHA_Final(&s, keyspace + 20);
d39f364a 2622}
2623
2624/*
7cca0d81 2625 * Handle the SSH2 transport layer.
e5574168 2626 */
7cca0d81 2627static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt)
e5574168 2628{
7bd5a860 2629 static int i, j, len, nbits, pbits;
e5574168 2630 static char *str;
a92dd380 2631 static Bignum p, g, e, f, K;
2632 static int kex_init_value, kex_reply_value;
7591b9ff 2633 static const struct ssh_mac **maclist;
8b2715b2 2634 static int nmacs;
0a3f1d48 2635 static const struct ssh2_cipher *cscipher_tobe = NULL;
2636 static const struct ssh2_cipher *sccipher_tobe = NULL;
57476f6b 2637 static const struct ssh_mac *csmac_tobe = NULL;
2638 static const struct ssh_mac *scmac_tobe = NULL;
2639 static const struct ssh_compress *cscomp_tobe = NULL;
2640 static const struct ssh_compress *sccomp_tobe = NULL;
d5859615 2641 static char *hostkeydata, *sigdata, *keystr, *fingerprint;
e5574168 2642 static int hostkeylen, siglen;
e055a386 2643 static void *hkey; /* actual host key */
e5574168 2644 static unsigned char exchange_hash[20];
d39f364a 2645 static unsigned char keyspace[40];
0a3f1d48 2646 static const struct ssh2_ciphers *preferred_cipher;
4ba9b64b 2647 static const struct ssh_compress *preferred_comp;
0db56f73 2648 static int first_kex;
e5574168 2649
2650 crBegin;
7cca0d81 2651 random_init();
0db56f73 2652 first_kex = 1;
e5574168 2653
5e8358ad 2654 /*
4ba9b64b 2655 * Set up the preferred cipher and compression.
5e8358ad 2656 */
2657 if (cfg.cipher == CIPHER_BLOWFISH) {
32874aea 2658 preferred_cipher = &ssh2_blowfish;
5e8358ad 2659 } else if (cfg.cipher == CIPHER_DES) {
32874aea 2660 logevent("Single DES not supported in SSH2; using 3DES");
2661 preferred_cipher = &ssh2_3des;
5e8358ad 2662 } else if (cfg.cipher == CIPHER_3DES) {
32874aea 2663 preferred_cipher = &ssh2_3des;
0a3f1d48 2664 } else if (cfg.cipher == CIPHER_AES) {
32874aea 2665 preferred_cipher = &ssh2_aes;
5e8358ad 2666 } else {
32874aea 2667 /* Shouldn't happen, but we do want to initialise to _something_. */
2668 preferred_cipher = &ssh2_3des;
5e8358ad 2669 }
4ba9b64b 2670 if (cfg.compression)
2671 preferred_comp = &ssh_zlib;
2672 else
2673 preferred_comp = &ssh_comp_none;
5e8358ad 2674
7591b9ff 2675 /*
2676 * Be prepared to work around the buggy MAC problem.
2677 */
7d503c31 2678 if (cfg.buggymac || (ssh_remote_bugs & BUG_SSH2_HMAC))
32874aea 2679 maclist = buggymacs, nmacs = lenof(buggymacs);
7591b9ff 2680 else
32874aea 2681 maclist = macs, nmacs = lenof(macs);
7591b9ff 2682
32874aea 2683 begin_key_exchange:
e5574168 2684 /*
2685 * Construct and send our key exchange packet.
2686 */
2687 ssh2_pkt_init(SSH2_MSG_KEXINIT);
2688 for (i = 0; i < 16; i++)
32874aea 2689 ssh2_pkt_addbyte((unsigned char) random_byte());
e5574168 2690 /* List key exchange algorithms. */
2691 ssh2_pkt_addstring_start();
2692 for (i = 0; i < lenof(kex_algs); i++) {
32874aea 2693 ssh2_pkt_addstring_str(kex_algs[i]->name);
2694 if (i < lenof(kex_algs) - 1)
2695 ssh2_pkt_addstring_str(",");
e5574168 2696 }
2697 /* List server host key algorithms. */
2698 ssh2_pkt_addstring_start();
2699 for (i = 0; i < lenof(hostkey_algs); i++) {
32874aea 2700 ssh2_pkt_addstring_str(hostkey_algs[i]->name);
2701 if (i < lenof(hostkey_algs) - 1)
2702 ssh2_pkt_addstring_str(",");
e5574168 2703 }
2704 /* List client->server encryption algorithms. */
2705 ssh2_pkt_addstring_start();
32874aea 2706 for (i = 0; i < lenof(ciphers) + 1; i++) {
2707 const struct ssh2_ciphers *c =
2708 i == 0 ? preferred_cipher : ciphers[i - 1];
2709 for (j = 0; j < c->nciphers; j++) {
2710 ssh2_pkt_addstring_str(c->list[j]->name);
2711 if (i < lenof(ciphers) || j < c->nciphers - 1)
2712 ssh2_pkt_addstring_str(",");
2713 }
e5574168 2714 }
2715 /* List server->client encryption algorithms. */
2716 ssh2_pkt_addstring_start();
32874aea 2717 for (i = 0; i < lenof(ciphers) + 1; i++) {
2718 const struct ssh2_ciphers *c =
2719 i == 0 ? preferred_cipher : ciphers[i - 1];
2720 for (j = 0; j < c->nciphers; j++) {
2721 ssh2_pkt_addstring_str(c->list[j]->name);
2722 if (i < lenof(ciphers) || j < c->nciphers - 1)
2723 ssh2_pkt_addstring_str(",");
2724 }
e5574168 2725 }
2726 /* List client->server MAC algorithms. */
2727 ssh2_pkt_addstring_start();
8b2715b2 2728 for (i = 0; i < nmacs; i++) {
32874aea 2729 ssh2_pkt_addstring_str(maclist[i]->name);
2730 if (i < nmacs - 1)
2731 ssh2_pkt_addstring_str(",");
e5574168 2732 }
2733 /* List server->client MAC algorithms. */
2734 ssh2_pkt_addstring_start();
8b2715b2 2735 for (i = 0; i < nmacs; i++) {
32874aea 2736 ssh2_pkt_addstring_str(maclist[i]->name);
2737 if (i < nmacs - 1)
2738 ssh2_pkt_addstring_str(",");
e5574168 2739 }
2740 /* List client->server compression algorithms. */
2741 ssh2_pkt_addstring_start();
32874aea 2742 for (i = 0; i < lenof(compressions) + 1; i++) {
2743 const struct ssh_compress *c =
2744 i == 0 ? preferred_comp : compressions[i - 1];
2745 ssh2_pkt_addstring_str(c->name);
2746 if (i < lenof(compressions))
2747 ssh2_pkt_addstring_str(",");
e5574168 2748 }
2749 /* List server->client compression algorithms. */
2750 ssh2_pkt_addstring_start();
32874aea 2751 for (i = 0; i < lenof(compressions) + 1; i++) {
2752 const struct ssh_compress *c =
2753 i == 0 ? preferred_comp : compressions[i - 1];
2754 ssh2_pkt_addstring_str(c->name);
2755 if (i < lenof(compressions))
2756 ssh2_pkt_addstring_str(",");
e5574168 2757 }
2758 /* List client->server languages. Empty list. */
2759 ssh2_pkt_addstring_start();
2760 /* List server->client languages. Empty list. */
2761 ssh2_pkt_addstring_start();
2762 /* First KEX packet does _not_ follow, because we're not that brave. */
2763 ssh2_pkt_addbool(FALSE);
2764 /* Reserved. */
2765 ssh2_pkt_adduint32(0);
0db56f73 2766
2767 exhash = exhashbase;
32874aea 2768 sha_string(&exhash, pktout.data + 5, pktout.length - 5);
0db56f73 2769
e5574168 2770 ssh2_pkt_send();
2771
32874aea 2772 if (!ispkt)
2773 crWaitUntil(ispkt);
2774 sha_string(&exhash, pktin.data + 5, pktin.length - 5);
e5574168 2775
2776 /*
2777 * Now examine the other side's KEXINIT to see what we're up
2778 * to.
2779 */
7cca0d81 2780 if (pktin.type != SSH2_MSG_KEXINIT) {
32874aea 2781 bombout(("expected key exchange packet from server"));
2782 crReturn(0);
7cca0d81 2783 }
32874aea 2784 kex = NULL;
2785 hostkey = NULL;
2786 cscipher_tobe = NULL;
2787 sccipher_tobe = NULL;
2788 csmac_tobe = NULL;
2789 scmac_tobe = NULL;
2790 cscomp_tobe = NULL;
2791 sccomp_tobe = NULL;
2792 pktin.savedpos += 16; /* skip garbage cookie */
e5574168 2793 ssh2_pkt_getstring(&str, &len); /* key exchange algorithms */
2794 for (i = 0; i < lenof(kex_algs); i++) {
32874aea 2795 if (in_commasep_string(kex_algs[i]->name, str, len)) {
2796 kex = kex_algs[i];
2797 break;
2798 }
e5574168 2799 }
2800 ssh2_pkt_getstring(&str, &len); /* host key algorithms */
2801 for (i = 0; i < lenof(hostkey_algs); i++) {
32874aea 2802 if (in_commasep_string(hostkey_algs[i]->name, str, len)) {
2803 hostkey = hostkey_algs[i];
2804 break;
2805 }
e5574168 2806 }
2807 ssh2_pkt_getstring(&str, &len); /* client->server cipher */
32874aea 2808 for (i = 0; i < lenof(ciphers) + 1; i++) {
2809 const struct ssh2_ciphers *c =
2810 i == 0 ? preferred_cipher : ciphers[i - 1];
2811 for (j = 0; j < c->nciphers; j++) {
2812 if (in_commasep_string(c->list[j]->name, str, len)) {
2813 cscipher_tobe = c->list[j];
2814 break;
2815 }
2816 }
2817 if (cscipher_tobe)
2818 break;
e5574168 2819 }
2820 ssh2_pkt_getstring(&str, &len); /* server->client cipher */
32874aea 2821 for (i = 0; i < lenof(ciphers) + 1; i++) {
2822 const struct ssh2_ciphers *c =
2823 i == 0 ? preferred_cipher : ciphers[i - 1];
2824 for (j = 0; j < c->nciphers; j++) {
2825 if (in_commasep_string(c->list[j]->name, str, len)) {
2826 sccipher_tobe = c->list[j];
2827 break;
2828 }
2829 }
2830 if (sccipher_tobe)
2831 break;
e5574168 2832 }
2833 ssh2_pkt_getstring(&str, &len); /* client->server mac */
8b2715b2 2834 for (i = 0; i < nmacs; i++) {
32874aea 2835 if (in_commasep_string(maclist[i]->name, str, len)) {
2836 csmac_tobe = maclist[i];
2837 break;
2838 }
e5574168 2839 }
2840 ssh2_pkt_getstring(&str, &len); /* server->client mac */
8b2715b2 2841 for (i = 0; i < nmacs; i++) {
32874aea 2842 if (in_commasep_string(maclist[i]->name, str, len)) {
2843 scmac_tobe = maclist[i];
2844 break;
2845 }
e5574168 2846 }
2847 ssh2_pkt_getstring(&str, &len); /* client->server compression */
32874aea 2848 for (i = 0; i < lenof(compressions) + 1; i++) {
2849 const struct ssh_compress *c =
2850 i == 0 ? preferred_comp : compressions[i - 1];
2851 if (in_commasep_string(c->name, str, len)) {
2852 cscomp_tobe = c;
2853 break;
2854 }
e5574168 2855 }
2856 ssh2_pkt_getstring(&str, &len); /* server->client compression */
32874aea 2857 for (i = 0; i < lenof(compressions) + 1; i++) {
2858 const struct ssh_compress *c =
2859 i == 0 ? preferred_comp : compressions[i - 1];
2860 if (in_commasep_string(c->name, str, len)) {
2861 sccomp_tobe = c;
2862 break;
2863 }
e5574168 2864 }
e5574168 2865
2866 /*
7bd5a860 2867 * Work out the number of bits of key we will need from the key
2868 * exchange. We start with the maximum key length of either
2869 * cipher...
2870 */
2871 {
32874aea 2872 int csbits, scbits;
7bd5a860 2873
2874 csbits = cscipher_tobe->keylen;
2875 scbits = sccipher_tobe->keylen;
2876 nbits = (csbits > scbits ? csbits : scbits);
2877 }
2878 /* The keys only have 160-bit entropy, since they're based on
2879 * a SHA-1 hash. So cap the key size at 160 bits. */
32874aea 2880 if (nbits > 160)
2881 nbits = 160;
7bd5a860 2882
2883 /*
a92dd380 2884 * If we're doing Diffie-Hellman group exchange, start by
2885 * requesting a group.
e5574168 2886 */
a92dd380 2887 if (kex == &ssh_diffiehellman_gex) {
32874aea 2888 logevent("Doing Diffie-Hellman group exchange");
2889 /*
2890 * Work out how big a DH group we will need to allow that
2891 * much data.
7bd5a860 2892 */
32874aea 2893 pbits = 512 << ((nbits - 1) / 64);
2894 ssh2_pkt_init(SSH2_MSG_KEX_DH_GEX_REQUEST);
2895 ssh2_pkt_adduint32(pbits);
2896 ssh2_pkt_send();
2897
2898 crWaitUntil(ispkt);
2899 if (pktin.type != SSH2_MSG_KEX_DH_GEX_GROUP) {
2900 bombout(("expected key exchange group packet from server"));
2901 crReturn(0);
2902 }
2903 p = ssh2_pkt_getmp();
2904 g = ssh2_pkt_getmp();
2905 dh_setup_group(p, g);
2906 kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT;
2907 kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY;
a92dd380 2908 } else {
32874aea 2909 dh_setup_group1();
2910 kex_init_value = SSH2_MSG_KEXDH_INIT;
2911 kex_reply_value = SSH2_MSG_KEXDH_REPLY;
8d5de777 2912 }
e5574168 2913
a92dd380 2914 logevent("Doing Diffie-Hellman key exchange");
e5574168 2915 /*
a92dd380 2916 * Now generate and send e for Diffie-Hellman.
e5574168 2917 */
32874aea 2918 e = dh_create_e(nbits * 2);
a92dd380 2919 ssh2_pkt_init(kex_init_value);
e5574168 2920 ssh2_pkt_addmp(e);
2921 ssh2_pkt_send();
2922
2923 crWaitUntil(ispkt);
a92dd380 2924 if (pktin.type != kex_reply_value) {
32874aea 2925 bombout(("expected key exchange reply packet from server"));
2926 crReturn(0);
7cca0d81 2927 }
e5574168 2928 ssh2_pkt_getstring(&hostkeydata, &hostkeylen);
2929 f = ssh2_pkt_getmp();
e5574168 2930 ssh2_pkt_getstring(&sigdata, &siglen);
2931
2932 K = dh_find_K(f);
e5574168 2933
2934 sha_string(&exhash, hostkeydata, hostkeylen);
a92dd380 2935 if (kex == &ssh_diffiehellman_gex) {
32874aea 2936 sha_uint32(&exhash, pbits);
2937 sha_mpint(&exhash, p);
2938 sha_mpint(&exhash, g);
a92dd380 2939 }
e5574168 2940 sha_mpint(&exhash, e);
2941 sha_mpint(&exhash, f);
2942 sha_mpint(&exhash, K);
2943 SHA_Final(&exhash, exchange_hash);
2944
3709bfe9 2945 dh_cleanup();
2946
7cca0d81 2947#if 0
765c4200 2948 debug(("Exchange hash is:\n"));
2949 dmemdump(exchange_hash, 20);
7cca0d81 2950#endif
2951
e055a386 2952 hkey = hostkey->newkey(hostkeydata, hostkeylen);
2953 if (!hostkey->verifysig(hkey, sigdata, siglen, exchange_hash, 20)) {
32874aea 2954 bombout(("Server failed host key check"));
2955 crReturn(0);
8d5de777 2956 }
e5574168 2957
2958 /*
7cca0d81 2959 * Expect SSH2_MSG_NEWKEYS from server.
d39f364a 2960 */
7cca0d81 2961 crWaitUntil(ispkt);
8d5de777 2962 if (pktin.type != SSH2_MSG_NEWKEYS) {
32874aea 2963 bombout(("expected new-keys packet from server"));
2964 crReturn(0);
8d5de777 2965 }
d39f364a 2966
2967 /*
7cca0d81 2968 * Authenticate remote host: verify host key. (We've already
2969 * checked the signature of the exchange hash.)
e5574168 2970 */
e055a386 2971 keystr = hostkey->fmtkey(hkey);
2972 fingerprint = hostkey->fingerprint(hkey);
d4857987 2973 verify_ssh_host_key(savedhost, savedport, hostkey->keytype,
32874aea 2974 keystr, fingerprint);
2975 if (first_kex) { /* don't bother logging this in rekeys */
5e0d7cb8 2976 logevent("Host key fingerprint is:");
2977 logevent(fingerprint);
2978 }
dcbde236 2979 sfree(fingerprint);
2980 sfree(keystr);
e055a386 2981 hostkey->freekey(hkey);
d39f364a 2982
2983 /*
7cca0d81 2984 * Send SSH2_MSG_NEWKEYS.
d39f364a 2985 */
2986 ssh2_pkt_init(SSH2_MSG_NEWKEYS);
2987 ssh2_pkt_send();
d39f364a 2988
2989 /*
2990 * Create and initialise session keys.
2991 */
2992 cscipher = cscipher_tobe;
2993 sccipher = sccipher_tobe;
2994 csmac = csmac_tobe;
2995 scmac = scmac_tobe;
2996 cscomp = cscomp_tobe;
2997 sccomp = sccomp_tobe;
4ba9b64b 2998 cscomp->compress_init();
2999 sccomp->decompress_init();
d39f364a 3000 /*
5e0d7cb8 3001 * Set IVs after keys. Here we use the exchange hash from the
3002 * _first_ key exchange.
d39f364a 3003 */
5e0d7cb8 3004 if (first_kex)
65a22376 3005 memcpy(ssh2_session_id, exchange_hash, sizeof(exchange_hash));
3006 ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'C', keyspace);
5e0d7cb8 3007 cscipher->setcskey(keyspace);
65a22376 3008 ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'D', keyspace);
5e0d7cb8 3009 sccipher->setsckey(keyspace);
65a22376 3010 ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'A', keyspace);
5e0d7cb8 3011 cscipher->setcsiv(keyspace);
65a22376 3012 ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'B', keyspace);
5e0d7cb8 3013 sccipher->setsciv(keyspace);
65a22376 3014 ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'E', keyspace);
5e0d7cb8 3015 csmac->setcskey(keyspace);
65a22376 3016 ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'F', keyspace);
5e0d7cb8 3017 scmac->setsckey(keyspace);
d39f364a 3018
033b4cef 3019 /*
0db56f73 3020 * If this is the first key exchange phase, we must pass the
3021 * SSH2_MSG_NEWKEYS packet to the next layer, not because it
3022 * wants to see it but because it will need time to initialise
3023 * itself before it sees an actual packet. In subsequent key
3024 * exchange phases, we don't pass SSH2_MSG_NEWKEYS on, because
3025 * it would only confuse the layer above.
3026 */
3027 if (!first_kex) {
32874aea 3028 crReturn(0);
0db56f73 3029 }
3030 first_kex = 0;
3031
3032 /*
7cca0d81 3033 * Now we're encrypting. Begin returning 1 to the protocol main
3034 * function so that other things can run on top of the
3035 * transport. If we ever see a KEXINIT, we must go back to the
3036 * start.
033b4cef 3037 */
e96adf72 3038 while (!(ispkt && pktin.type == SSH2_MSG_KEXINIT)) {
32874aea 3039 crReturn(1);
e96adf72 3040 }
5e0d7cb8 3041 logevent("Server initiated key re-exchange");
7cca0d81 3042 goto begin_key_exchange;
e5574168 3043
3044 crFinish(1);
3045}
3046
7cca0d81 3047/*
783415f8 3048 * Add data to an SSH2 channel output buffer.
3049 */
32874aea 3050static void ssh2_add_channel_data(struct ssh_channel *c, char *buf,
3051 int len)
3052{
3053 if (c->v2.outbufsize < c->v2.outbuflen + len) {
3054 c->v2.outbufsize = c->v2.outbuflen + len + 1024;
3055 c->v2.outbuffer = srealloc(c->v2.outbuffer, c->v2.outbufsize);
3056 }
3057 memcpy(c->v2.outbuffer + c->v2.outbuflen, buf, len);
783415f8 3058 c->v2.outbuflen += len;
3059}
3060
3061/*
3062 * Attempt to send data on an SSH2 channel.
3063 */
32874aea 3064static void ssh2_try_send(struct ssh_channel *c)
3065{
3066 while (c->v2.remwindow > 0 && c->v2.outbuflen > 0) {
3067 unsigned len = c->v2.remwindow;
3068 if (len > c->v2.outbuflen)
3069 len = c->v2.outbuflen;
3070 if (len > c->v2.remmaxpkt)
3071 len = c->v2.remmaxpkt;
3072 ssh2_pkt_init(SSH2_MSG_CHANNEL_DATA);
3073 ssh2_pkt_adduint32(c->remoteid);
3074 ssh2_pkt_addstring_start();
3075 ssh2_pkt_addstring_data(c->v2.outbuffer, len);
3076 ssh2_pkt_send();
3077 c->v2.outbuflen -= len;
3078 memmove(c->v2.outbuffer, c->v2.outbuffer + len, c->v2.outbuflen);
3079 c->v2.remwindow -= len;
783415f8 3080 }
3081}
3082
3083/*
7cca0d81 3084 * Handle the SSH2 userauth and connection layers.
3085 */
3086static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt)
3087{
7cca0d81 3088 static unsigned long remote_winsize;
3089 static unsigned long remote_maxpkt;
65a22376 3090 static enum {
32874aea 3091 AUTH_INVALID, AUTH_PUBLICKEY_AGENT, AUTH_PUBLICKEY_FILE,
3092 AUTH_PASSWORD
65a22376 3093 } method;
1408a877 3094 static enum {
32874aea 3095 AUTH_TYPE_NONE,
3096 AUTH_TYPE_PUBLICKEY,
3097 AUTH_TYPE_PUBLICKEY_OFFER_LOUD,
3098 AUTH_TYPE_PUBLICKEY_OFFER_QUIET,
3099 AUTH_TYPE_PASSWORD
1408a877 3100 } type;
1983e559 3101 static int gotit, need_pw, can_pubkey, can_passwd;
3102 static int tried_pubkey_config, tried_agent;
1408a877 3103 static int we_are_in;
65a22376 3104 static char username[100];
3105 static char pwprompt[200];
3106 static char password[100];
7cca0d81 3107
e5574168 3108 crBegin;
3109
7cca0d81 3110 /*
3111 * Request userauth protocol, and await a response to it.
3112 */
3113 ssh2_pkt_init(SSH2_MSG_SERVICE_REQUEST);
3114 ssh2_pkt_addstring("ssh-userauth");
3115 ssh2_pkt_send();
3116 crWaitUntilV(ispkt);
8d5de777 3117 if (pktin.type != SSH2_MSG_SERVICE_ACCEPT) {
32874aea 3118 bombout(("Server refused user authentication protocol"));
3119 crReturnV;
8d5de777 3120 }
7cca0d81 3121
3122 /*
1408a877 3123 * We repeat this whole loop, including the username prompt,
3124 * until we manage a successful authentication. If the user
3125 * types the wrong _password_, they are sent back to the
3126 * beginning to try another username. (If they specify a
3127 * username in the config, they are never asked, even if they
3128 * do give a wrong password.)
3129 *
3130 * I think this best serves the needs of
3131 *
3132 * - the people who have no configuration, no keys, and just
3133 * want to try repeated (username,password) pairs until they
3134 * type both correctly
3135 *
3136 * - people who have keys and configuration but occasionally
3137 * need to fall back to passwords
3138 *
3139 * - people with a key held in Pageant, who might not have
3140 * logged in to a particular machine before; so they want to
3141 * type a username, and then _either_ their key will be
3142 * accepted, _or_ they will type a password. If they mistype
3143 * the username they will want to be able to get back and
3144 * retype it!
7cca0d81 3145 */
1408a877 3146 do {
3147 static int pos;
7cca0d81 3148 static char c;
e5574168 3149
1408a877 3150 /*
3151 * Get a username.
3152 */
3153 pos = 0;
67779be7 3154 if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
32874aea 3155 if (ssh_get_line) {
3156 if (!ssh_get_line("login as: ",
3157 username, sizeof(username), FALSE)) {
3158 /*
3159 * get_line failed to get a username.
3160 * Terminate.
3161 */
3162 logevent("No username provided. Abandoning session.");
3163 ssh_state = SSH_STATE_CLOSED;
3164 crReturnV;
3165 }
3166 } else {
3167 c_write_str("login as: ");
3168 ssh_send_ok = 1;
3169 while (pos >= 0) {
3170 crWaitUntilV(!ispkt);
3171 while (inlen--)
3172 switch (c = *in++) {
3173 case 10:
3174 case 13:
3175 username[pos] = 0;
3176 pos = -1;
3177 break;
3178 case 8:
3179 case 127:
3180 if (pos > 0) {
3181 c_write_str("\b \b");
3182 pos--;
3183 }
3184 break;
3185 case 21:
3186 case 27:
3187 while (pos > 0) {
3188 c_write_str("\b \b");
3189 pos--;
3190 }
3191 break;
3192 case 3:
3193 case 4:
3194 random_save_seed();
3195 exit(0);
3196 break;
3197 default:
3198 if (((c >= ' ' && c <= '~') ||
51b2fb65 3199 ((unsigned char) c >= 160))
3200 && pos < sizeof(username)-1) {
32874aea 3201 username[pos++] = c;
3202 c_write(&c, 1);
3203 }
3204 break;
3205 }
3206 }
3207 }
1408a877 3208 c_write_str("\r\n");
7cca0d81 3209 username[strcspn(username, "\n\r")] = '\0';
3210 } else {
3211 char stuff[200];
3212 strncpy(username, cfg.username, 99);
3213 username[99] = '\0';
65a22376 3214 if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
7cca0d81 3215 sprintf(stuff, "Using username \"%s\".\r\n", username);
1408a877 3216 c_write_str(stuff);
7cca0d81 3217 }
3218 }
3219
65a22376 3220 /*
1408a877 3221 * Send an authentication request using method "none": (a)
3222 * just in case it succeeds, and (b) so that we know what
3223 * authentication methods we can usefully try next.
65a22376 3224 */
1408a877 3225 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
3226 ssh2_pkt_addstring(username);
32874aea 3227 ssh2_pkt_addstring("ssh-connection"); /* service requested */
1408a877 3228 ssh2_pkt_addstring("none"); /* method */
3229 ssh2_pkt_send();
3230 type = AUTH_TYPE_NONE;
3231 gotit = FALSE;
3232 we_are_in = FALSE;
7cca0d81 3233
1408a877 3234 tried_pubkey_config = FALSE;
1983e559 3235 tried_agent = FALSE;
65a22376 3236
1408a877 3237 while (1) {
3238 /*
3239 * Wait for the result of the last authentication request.
3240 */
3241 if (!gotit)
3242 crWaitUntilV(ispkt);
3243 while (pktin.type == SSH2_MSG_USERAUTH_BANNER) {
32874aea 3244 char *banner;
3245 int size;
3246 /*
3247 * Don't show the banner if we're operating in
3248 * non-verbose non-interactive mode. (It's probably
3249 * a script, which means nobody will read the
3250 * banner _anyway_, and moreover the printing of
3251 * the banner will screw up processing on the
3252 * output of (say) plink.)
3253 */
3254 if (flags & (FLAG_VERBOSE | FLAG_INTERACTIVE)) {
3255 ssh2_pkt_getstring(&banner, &size);
3256 if (banner)
3257 c_write_untrusted(banner, size);
3258 }
1408a877 3259 crWaitUntilV(ispkt);
3260 }
3261 if (pktin.type == SSH2_MSG_USERAUTH_SUCCESS) {
3262 logevent("Access granted");
3263 we_are_in = TRUE;
3264 break;
3265 }
65a22376 3266
1408a877 3267 if (pktin.type != SSH2_MSG_USERAUTH_FAILURE) {
32874aea 3268 bombout(
3269 ("Strange packet received during authentication: type %d",
1408a877 3270 pktin.type));
38c4a8da 3271 crReturnV;
65a22376 3272 }
3273
1408a877 3274 gotit = FALSE;
65a22376 3275
1408a877 3276 /*
3277 * OK, we're now sitting on a USERAUTH_FAILURE message, so
3278 * we can look at the string in it and know what we can
3279 * helpfully try next.
3280 */
3281 {
3282 char *methods;
3283 int methlen;
3284 ssh2_pkt_getstring(&methods, &methlen);
3285 if (!ssh2_pkt_getbool()) {
3286 /*
3287 * We have received an unequivocal Access
3288 * Denied. This can translate to a variety of
3289 * messages:
3290 *
3291 * - if we'd just tried "none" authentication,
3292 * it's not worth printing anything at all
3293 *
3294 * - if we'd just tried a public key _offer_,
3295 * the message should be "Server refused our
3296 * key" (or no message at all if the key
3297 * came from Pageant)
3298 *
3299 * - if we'd just tried anything else, the
3300 * message really should be "Access denied".
3301 *
3302 * Additionally, if we'd just tried password
3303 * authentication, we should break out of this
3304 * whole loop so as to go back to the username
3305 * prompt.
3306 */
3307 if (type == AUTH_TYPE_NONE) {
3308 /* do nothing */
3309 } else if (type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD ||
3310 type == AUTH_TYPE_PUBLICKEY_OFFER_QUIET) {
3311 if (type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD)
3312 c_write_str("Server refused our key\r\n");
3313 logevent("Server refused public key");
3314 } else {
3315 c_write_str("Access denied\r\n");
3316 logevent("Access denied");
3317 if (type == AUTH_TYPE_PASSWORD) {
3318 we_are_in = FALSE;
3319 break;
3320 }
3321 }
3322 } else {
3323 c_write_str("Further authentication required\r\n");
3324 logevent("Further authentication required");
3325 }
65a22376 3326
32874aea 3327 can_pubkey =
3328 in_commasep_string("publickey", methods, methlen);
3329 can_passwd =
3330 in_commasep_string("password", methods, methlen);
1408a877 3331 }
65a22376 3332
1408a877 3333 method = 0;
65a22376 3334
78afa559 3335 if (!method && can_pubkey && agent_exists() && !tried_agent) {
1983e559 3336 /*
3337 * Attempt public-key authentication using Pageant.
3338 */
3339 static unsigned char request[5], *response, *p;
3340 static int responselen;
3341 static int i, nkeys;
3342 static int authed = FALSE;
3343 void *r;
3344
3345 tried_agent = TRUE;
3346
3347 logevent("Pageant is running. Requesting keys.");
3348
3349 /* Request the keys held by the agent. */
3350 PUT_32BIT(request, 1);
3351 request[4] = SSH2_AGENTC_REQUEST_IDENTITIES;
3352 agent_query(request, 5, &r, &responselen);
32874aea 3353 response = (unsigned char *) r;
95797139 3354 if (response && responselen >= 5 &&
32874aea 3355 response[4] == SSH2_AGENT_IDENTITIES_ANSWER) {
1983e559 3356 p = response + 5;
32874aea 3357 nkeys = GET_32BIT(p);
3358 p += 4;
3359 {
3360 char buf[64];
3361 sprintf(buf, "Pageant has %d SSH2 keys", nkeys);
3362 logevent(buf);
3363 }
1983e559 3364 for (i = 0; i < nkeys; i++) {
3365 static char *pkblob, *alg, *commentp;
3366 static int pklen, alglen, commentlen;
3367 static int siglen, retlen, len;
3368 static char *q, *agentreq, *ret;
3369
32874aea 3370 {
3371 char buf[64];
3372 sprintf(buf, "Trying Pageant key #%d", i);
3373 logevent(buf);
3374 }
3375 pklen = GET_32BIT(p);
3376 p += 4;
3377 pkblob = p;
3378 p += pklen;
1983e559 3379 alglen = GET_32BIT(pkblob);
3380 alg = pkblob + 4;
32874aea 3381 commentlen = GET_32BIT(p);
3382 p += 4;
3383 commentp = p;
3384 p += commentlen;
1983e559 3385 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
3386 ssh2_pkt_addstring(username);
32874aea 3387 ssh2_pkt_addstring("ssh-connection"); /* service requested */
3388 ssh2_pkt_addstring("publickey"); /* method */
3389 ssh2_pkt_addbool(FALSE); /* no signature included */
1983e559 3390 ssh2_pkt_addstring_start();
3391 ssh2_pkt_addstring_data(alg, alglen);
3392 ssh2_pkt_addstring_start();
3393 ssh2_pkt_addstring_data(pkblob, pklen);
3394 ssh2_pkt_send();
3395
3396 crWaitUntilV(ispkt);
3397 if (pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
3398 logevent("Key refused");
3399 continue;
3400 }
3401
32874aea 3402 if (flags & FLAG_VERBOSE) {
3403 c_write_str
3404 ("Authenticating with public key \"");
3405 c_write(commentp, commentlen);
3406 c_write_str("\" from agent\r\n");
3407 }
1983e559 3408
3409 /*
3410 * Server is willing to accept the key.
3411 * Construct a SIGN_REQUEST.
3412 */
3413 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
3414 ssh2_pkt_addstring(username);
32874aea 3415 ssh2_pkt_addstring("ssh-connection"); /* service requested */
3416 ssh2_pkt_addstring("publickey"); /* method */
1983e559 3417 ssh2_pkt_addbool(TRUE);
3418 ssh2_pkt_addstring_start();
3419 ssh2_pkt_addstring_data(alg, alglen);
3420 ssh2_pkt_addstring_start();
3421 ssh2_pkt_addstring_data(pkblob, pklen);
3422
3423 siglen = pktout.length - 5 + 4 + 20;
32874aea 3424 len = 1; /* message type */
3425 len += 4 + pklen; /* key blob */
3426 len += 4 + siglen; /* data to sign */
3427 len += 4; /* flags */
1983e559 3428 agentreq = smalloc(4 + len);
3429 PUT_32BIT(agentreq, len);
3430 q = agentreq + 4;
3431 *q++ = SSH2_AGENTC_SIGN_REQUEST;
32874aea 3432 PUT_32BIT(q, pklen);
3433 q += 4;
3434 memcpy(q, pkblob, pklen);
3435 q += pklen;
3436 PUT_32BIT(q, siglen);
3437 q += 4;
1983e559 3438 /* Now the data to be signed... */
32874aea 3439 PUT_32BIT(q, 20);
3440 q += 4;
3441 memcpy(q, ssh2_session_id, 20);
3442 q += 20;
3443 memcpy(q, pktout.data + 5, pktout.length - 5);
3444 q += pktout.length - 5;
1983e559 3445 /* And finally the (zero) flags word. */
3446 PUT_32BIT(q, 0);
32874aea 3447 agent_query(agentreq, len + 4, &ret, &retlen);
1983e559 3448 sfree(agentreq);
3449 if (ret) {
3450 if (ret[4] == SSH2_AGENT_SIGN_RESPONSE) {
3451 logevent("Sending Pageant's response");
3452 ssh2_pkt_addstring_start();
32874aea 3453 ssh2_pkt_addstring_data(ret + 9,
3454 GET_32BIT(ret +
3455 5));
1983e559 3456 ssh2_pkt_send();
3457 authed = TRUE;
3458 break;
3459 } else {
32874aea 3460 logevent
3461 ("Pageant failed to answer challenge");
1983e559 3462 sfree(ret);
3463 }
3464 }
3465 }
3466 if (authed)
3467 continue;
3468 }
3469 }
3470
32874aea 3471 if (!method && can_pubkey && *cfg.keyfile
3472 && !tried_pubkey_config) {
1408a877 3473 unsigned char *pub_blob;
3474 char *algorithm, *comment;
3475 int pub_blob_len;
65a22376 3476
1408a877 3477 tried_pubkey_config = TRUE;
65a22376 3478
65a22376 3479 /*
1408a877 3480 * Try the public key supplied in the configuration.
3481 *
3482 * First, offer the public blob to see if the server is
3483 * willing to accept it.
65a22376 3484 */
1408a877 3485 pub_blob = ssh2_userkey_loadpub(cfg.keyfile, &algorithm,
3486 &pub_blob_len);
3487 if (pub_blob) {
3488 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
3489 ssh2_pkt_addstring(username);
32874aea 3490 ssh2_pkt_addstring("ssh-connection"); /* service requested */
3491 ssh2_pkt_addstring("publickey"); /* method */
3492 ssh2_pkt_addbool(FALSE); /* no signature included */
1408a877 3493 ssh2_pkt_addstring(algorithm);
3494 ssh2_pkt_addstring_start();
3495 ssh2_pkt_addstring_data(pub_blob, pub_blob_len);
3496 ssh2_pkt_send();
32874aea 3497 logevent("Offered public key"); /* FIXME */
1408a877 3498
3499 crWaitUntilV(ispkt);
3500 if (pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
3501 gotit = TRUE;
3502 type = AUTH_TYPE_PUBLICKEY_OFFER_LOUD;
32874aea 3503 continue; /* key refused; give up on it */
1408a877 3504 }
65a22376 3505
1408a877 3506 logevent("Offer of public key accepted");
65a22376 3507 /*
1408a877 3508 * Actually attempt a serious authentication using
3509 * the key.
65a22376 3510 */
1408a877 3511 if (ssh2_userkey_encrypted(cfg.keyfile, &comment)) {
32874aea 3512 sprintf(pwprompt,
3513 "Passphrase for key \"%.100s\": ",
3514 comment);
1408a877 3515 need_pw = TRUE;
3516 } else {
3517 need_pw = FALSE;
3518 }
3519 c_write_str("Authenticating with public key \"");
3520 c_write_str(comment);
3521 c_write_str("\"\r\n");
3522 method = AUTH_PUBLICKEY_FILE;
65a22376 3523 }
1408a877 3524 }
3525
3526 if (!method && can_passwd) {
3527 method = AUTH_PASSWORD;
32874aea 3528 sprintf(pwprompt, "%.90s@%.90s's password: ", username,
3529 savedhost);
1408a877 3530 need_pw = TRUE;
3531 }
3532
3533 if (need_pw) {
fa17a66e 3534 if (ssh_get_line) {
3535 if (!ssh_get_line(pwprompt, password,
32874aea 3536 sizeof(password), TRUE)) {
1408a877 3537 /*
fa17a66e 3538 * get_line failed to get a password (for
3539 * example because one was supplied on the
3540 * command line which has already failed to
3541 * work). Terminate.
1408a877 3542 */
2bc6a386 3543 ssh2_pkt_init(SSH2_MSG_DISCONNECT);
3544 ssh2_pkt_adduint32(SSH2_DISCONNECT_BY_APPLICATION);
3545 ssh2_pkt_addstring
3546 ("No more passwords available to try");
3547 ssh2_pkt_addstring("en"); /* language tag */
3548 ssh2_pkt_send();
3549 connection_fatal("Unable to authenticate");
1408a877 3550 ssh_state = SSH_STATE_CLOSED;
3551 crReturnV;
3552 }
3553 } else {
3554 static int pos = 0;
3555 static char c;
3556
3557 c_write_str(pwprompt);
3558 ssh_send_ok = 1;
3559
3560 pos = 0;
3561 while (pos >= 0) {
3562 crWaitUntilV(!ispkt);
32874aea 3563 while (inlen--)
3564 switch (c = *in++) {
3565 case 10:
3566 case 13:
3567 password[pos] = 0;
3568 pos = -1;
3569 break;
3570 case 8:
3571 case 127:
3572 if (pos > 0)
3573 pos--;
3574 break;
3575 case 21:
3576 case 27:
3577 pos = 0;
3578 break;
3579 case 3:
3580 case 4:
3581 random_save_seed();
3582 exit(0);
3583 break;
3584 default:
51b2fb65 3585 if (pos < sizeof(password)-1)
32874aea 3586 password[pos++] = c;
3587 break;
3588 }
65a22376 3589 }
1408a877 3590 c_write_str("\r\n");
65a22376 3591 }
65a22376 3592 }
65a22376 3593
1408a877 3594 if (method == AUTH_PUBLICKEY_FILE) {
3595 /*
3596 * We have our passphrase. Now try the actual authentication.
3597 */
3598 struct ssh2_userkey *key;
65a22376 3599
1408a877 3600 key = ssh2_load_userkey(cfg.keyfile, password);
3601 if (key == SSH2_WRONG_PASSPHRASE || key == NULL) {
3602 if (key == SSH2_WRONG_PASSPHRASE) {
3603 c_write_str("Wrong passphrase\r\n");
3604 tried_pubkey_config = FALSE;
3605 } else {
3606 c_write_str("Unable to load private key\r\n");
3607 tried_pubkey_config = TRUE;
3608 }
3609 /* Send a spurious AUTH_NONE to return to the top. */
3610 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
3611 ssh2_pkt_addstring(username);
32874aea 3612 ssh2_pkt_addstring("ssh-connection"); /* service requested */
3613 ssh2_pkt_addstring("none"); /* method */
1408a877 3614 ssh2_pkt_send();
3615 type = AUTH_TYPE_NONE;
3616 } else {
3617 unsigned char *blob, *sigdata;
3618 int blob_len, sigdata_len;
65a22376 3619
1408a877 3620 /*
3621 * We have loaded the private key and the server
3622 * has announced that it's willing to accept it.
3623 * Hallelujah. Generate a signature and send it.
3624 */
3625 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
3626 ssh2_pkt_addstring(username);
32874aea 3627 ssh2_pkt_addstring("ssh-connection"); /* service requested */
3628 ssh2_pkt_addstring("publickey"); /* method */
1408a877 3629 ssh2_pkt_addbool(TRUE);
3630 ssh2_pkt_addstring(key->alg->name);
3631 blob = key->alg->public_blob(key->data, &blob_len);
3632 ssh2_pkt_addstring_start();
3633 ssh2_pkt_addstring_data(blob, blob_len);
3634 sfree(blob);
3635
3636 /*
3637 * The data to be signed is:
3638 *
3639 * string session-id
3640 *
3641 * followed by everything so far placed in the
3642 * outgoing packet.
3643 */
3644 sigdata_len = pktout.length - 5 + 4 + 20;
3645 sigdata = smalloc(sigdata_len);
3646 PUT_32BIT(sigdata, 20);
32874aea 3647 memcpy(sigdata + 4, ssh2_session_id, 20);
3648 memcpy(sigdata + 24, pktout.data + 5,
3649 pktout.length - 5);
3650 blob =
3651 key->alg->sign(key->data, sigdata, sigdata_len,
3652 &blob_len);
1408a877 3653 ssh2_pkt_addstring_start();
3654 ssh2_pkt_addstring_data(blob, blob_len);
3655 sfree(blob);
3656 sfree(sigdata);
3657
3658 ssh2_pkt_send();
3659 type = AUTH_TYPE_PUBLICKEY;
3660 }
3661 } else if (method == AUTH_PASSWORD) {
65a22376 3662 /*
1408a877 3663 * We send the password packet lumped tightly together with
3664 * an SSH_MSG_IGNORE packet. The IGNORE packet contains a
3665 * string long enough to make the total length of the two
3666 * packets constant. This should ensure that a passive
3667 * listener doing traffic analyis can't work out the length
3668 * of the password.
3669 *
3670 * For this to work, we need an assumption about the
3671 * maximum length of the password packet. I think 256 is
3672 * pretty conservative. Anyone using a password longer than
3673 * that probably doesn't have much to worry about from
3674 * people who find out how long their password is!
65a22376 3675 */
3676 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
3677 ssh2_pkt_addstring(username);
32874aea 3678 ssh2_pkt_addstring("ssh-connection"); /* service requested */
1408a877 3679 ssh2_pkt_addstring("password");
3680 ssh2_pkt_addbool(FALSE);
3681 ssh2_pkt_addstring(password);
3682 ssh2_pkt_defer();
65a22376 3683 /*
1408a877 3684 * We'll include a string that's an exact multiple of the
3685 * cipher block size. If the cipher is NULL for some
3686 * reason, we don't do this trick at all because we gain
3687 * nothing by it.
65a22376 3688 */
32874aea 3689 if (cscipher) {
3690 int stringlen, i;
3691
3692 stringlen = (256 - deferred_len);
3693 stringlen += cscipher->blksize - 1;
3694 stringlen -= (stringlen % cscipher->blksize);
3695 if (cscomp) {
3696 /*
3697 * Temporarily disable actual compression,
3698 * so we can guarantee to get this string
3699 * exactly the length we want it. The
3700 * compression-disabling routine should
3701 * return an integer indicating how many
3702 * bytes we should adjust our string length
3703 * by.
3704 */
3705 stringlen -= cscomp->disable_compression();
3706 }
1408a877 3707 ssh2_pkt_init(SSH2_MSG_IGNORE);
3708 ssh2_pkt_addstring_start();
6e9e9520 3709 for (i = 0; i < stringlen; i++) {
32874aea 3710 char c = (char) random_byte();
3711 ssh2_pkt_addstring_data(&c, 1);
65a22376 3712 }
1408a877 3713 ssh2_pkt_defer();
65a22376 3714 }
39065bed 3715 ssh_pkt_defersend();
0d43337a 3716 logevent("Sent password");
1408a877 3717 type = AUTH_TYPE_PASSWORD;
3718 } else {
32874aea 3719 c_write_str
3720 ("No supported authentication methods left to try!\r\n");
3721 logevent
3722 ("No supported authentications offered. Disconnecting");
1408a877 3723 ssh2_pkt_init(SSH2_MSG_DISCONNECT);
3724 ssh2_pkt_adduint32(SSH2_DISCONNECT_BY_APPLICATION);
32874aea 3725 ssh2_pkt_addstring
3726 ("No supported authentication methods available");
3727 ssh2_pkt_addstring("en"); /* language tag */
1408a877 3728 ssh2_pkt_send();
3729 ssh_state = SSH_STATE_CLOSED;
3730 crReturnV;
65a22376 3731 }
65a22376 3732 }
1408a877 3733 } while (!we_are_in);
7cca0d81 3734
3735 /*
3736 * Now we're authenticated for the connection protocol. The
3737 * connection protocol will automatically have started at this
3738 * point; there's no need to send SERVICE_REQUEST.
3739 */
3740
3741 /*
3742 * So now create a channel with a session in it.
3743 */
d2371c81 3744 ssh_channels = newtree234(ssh_channelcmp);
dcbde236 3745 mainchan = smalloc(sizeof(struct ssh_channel));
d2371c81 3746 mainchan->localid = alloc_channel_id();
7cca0d81 3747 ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN);
3748 ssh2_pkt_addstring("session");
d211621f 3749 ssh2_pkt_adduint32(mainchan->localid);
32874aea 3750 ssh2_pkt_adduint32(0x8000UL); /* our window size */
3751 ssh2_pkt_adduint32(0x4000UL); /* our max pkt size */
7cca0d81 3752 ssh2_pkt_send();
3753 crWaitUntilV(ispkt);
3754 if (pktin.type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
32874aea 3755 bombout(("Server refused to open a session"));
3756 crReturnV;
3757 /* FIXME: error data comes back in FAILURE packet */
7cca0d81 3758 }
d211621f 3759 if (ssh2_pkt_getuint32() != mainchan->localid) {
32874aea 3760 bombout(("Server's channel confirmation cited wrong channel"));
3761 crReturnV;
7cca0d81 3762 }
d211621f 3763 mainchan->remoteid = ssh2_pkt_getuint32();
783415f8 3764 mainchan->type = CHAN_MAINSESSION;
3765 mainchan->closes = 0;
3766 mainchan->v2.remwindow = ssh2_pkt_getuint32();
3767 mainchan->v2.remmaxpkt = ssh2_pkt_getuint32();
3768 mainchan->v2.outbuffer = NULL;
3769 mainchan->v2.outbuflen = mainchan->v2.outbufsize = 0;
783415f8 3770 add234(ssh_channels, mainchan);
7cca0d81 3771 logevent("Opened channel for session");
3772
3773 /*
783415f8 3774 * Potentially enable X11 forwarding.
3775 */
3776 if (cfg.x11_forward) {
32874aea 3777 char proto[20], data[64];
3778 logevent("Requesting X11 forwarding");
3779 x11_invent_auth(proto, sizeof(proto), data, sizeof(data));
3780 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
3781 ssh2_pkt_adduint32(mainchan->remoteid);
3782 ssh2_pkt_addstring("x11-req");
3783 ssh2_pkt_addbool(1); /* want reply */
3784 ssh2_pkt_addbool(0); /* many connections */
3785 ssh2_pkt_addstring(proto);
3786 ssh2_pkt_addstring(data);
3787 ssh2_pkt_adduint32(0); /* screen number */
3788 ssh2_pkt_send();
3789
3790 do {
3791 crWaitUntilV(ispkt);
3792 if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
3793 unsigned i = ssh2_pkt_getuint32();
3794 struct ssh_channel *c;
3795 c = find234(ssh_channels, &i, ssh_channelfind);
3796 if (!c)
3797 continue; /* nonexistent channel */
3798 c->v2.remwindow += ssh2_pkt_getuint32();
3799 }
3800 } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
3801
3802 if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
3803 if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
3804 bombout(("Server got confused by X11 forwarding request"));
3805 crReturnV;
3806 }
3807 logevent("X11 forwarding refused");
3808 } else {
3809 logevent("X11 forwarding enabled");
783415f8 3810 ssh_X11_fwd_enabled = TRUE;
32874aea 3811 }
783415f8 3812 }
3813
3814 /*
36c2a3e9 3815 * Potentially enable agent forwarding.
3816 */
3817 if (cfg.agentfwd && agent_exists()) {
32874aea 3818 logevent("Requesting OpenSSH-style agent forwarding");
3819 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
3820 ssh2_pkt_adduint32(mainchan->remoteid);
3821 ssh2_pkt_addstring("auth-agent-req@openssh.com");
3822 ssh2_pkt_addbool(1); /* want reply */
3823 ssh2_pkt_send();
3824
3825 do {
3826 crWaitUntilV(ispkt);
3827 if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
3828 unsigned i = ssh2_pkt_getuint32();
3829 struct ssh_channel *c;
3830 c = find234(ssh_channels, &i, ssh_channelfind);
3831 if (!c)
3832 continue; /* nonexistent channel */
3833 c->v2.remwindow += ssh2_pkt_getuint32();
3834 }
3835 } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
3836
3837 if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
3838 if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
3839 bombout(
3840 ("Server got confused by agent forwarding request"));
3841 crReturnV;
3842 }
3843 logevent("Agent forwarding refused");
3844 } else {
3845 logevent("Agent forwarding enabled");
36c2a3e9 3846 ssh_agentfwd_enabled = TRUE;
32874aea 3847 }
36c2a3e9 3848 }
3849
3850 /*
7cca0d81 3851 * Now allocate a pty for the session.
3852 */
67779be7 3853 if (!cfg.nopty) {
32874aea 3854 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
3855 ssh2_pkt_adduint32(mainchan->remoteid); /* recipient channel */
3856 ssh2_pkt_addstring("pty-req");
3857 ssh2_pkt_addbool(1); /* want reply */
3858 ssh2_pkt_addstring(cfg.termtype);
3859 ssh2_pkt_adduint32(cols);
3860 ssh2_pkt_adduint32(rows);
3861 ssh2_pkt_adduint32(0); /* pixel width */
3862 ssh2_pkt_adduint32(0); /* pixel height */
3863 ssh2_pkt_addstring_start();
3864 ssh2_pkt_addstring_data("\0", 1); /* TTY_OP_END, no special options */
3865 ssh2_pkt_send();
3866 ssh_state = SSH_STATE_INTERMED;
3867
3868 do {
3869 crWaitUntilV(ispkt);
3870 if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
3871 unsigned i = ssh2_pkt_getuint32();
3872 struct ssh_channel *c;
3873 c = find234(ssh_channels, &i, ssh_channelfind);
3874 if (!c)
3875 continue; /* nonexistent channel */
3876 c->v2.remwindow += ssh2_pkt_getuint32();
3877 }
3878 } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
3879
3880 if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
3881 if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
3882 bombout(("Server got confused by pty request"));
3883 crReturnV;
3884 }
3885 c_write_str("Server refused to allocate pty\r\n");
3886 ssh_editing = ssh_echoing = 1;
3887 } else {
3888 logevent("Allocated pty");
3889 }
0965bee0 3890 } else {
32874aea 3891 ssh_editing = ssh_echoing = 1;
7cca0d81 3892 }
3893
3894 /*
67779be7 3895 * Start a shell or a remote command.
7cca0d81 3896 */
3897 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
32874aea 3898 ssh2_pkt_adduint32(mainchan->remoteid); /* recipient channel */
4a8fc3c4 3899 if (cfg.ssh_subsys) {
32874aea 3900 ssh2_pkt_addstring("subsystem");
3901 ssh2_pkt_addbool(1); /* want reply */
3902 ssh2_pkt_addstring(cfg.remote_cmd_ptr);
96621a84 3903 } else if (*cfg.remote_cmd_ptr) {
32874aea 3904 ssh2_pkt_addstring("exec");
3905 ssh2_pkt_addbool(1); /* want reply */
3906 ssh2_pkt_addstring(cfg.remote_cmd_ptr);
67779be7 3907 } else {
32874aea 3908 ssh2_pkt_addstring("shell");
3909 ssh2_pkt_addbool(1); /* want reply */
67779be7 3910 }
7cca0d81 3911 ssh2_pkt_send();
d211621f 3912 do {
32874aea 3913 crWaitUntilV(ispkt);
3914 if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
3915 unsigned i = ssh2_pkt_getuint32();
3916 struct ssh_channel *c;
3917 c = find234(ssh_channels, &i, ssh_channelfind);
3918 if (!c)
3919 continue; /* nonexistent channel */
3920 c->v2.remwindow += ssh2_pkt_getuint32();
3921 }
7cca0d81 3922 } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
3923 if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
32874aea 3924 if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
3925 bombout(("Server got confused by shell/command request"));
3926 crReturnV;
3927 }
3928 bombout(("Server refused to start a shell/command"));
3929 crReturnV;
7cca0d81 3930 } else {
32874aea 3931 logevent("Started a shell/command");
7cca0d81 3932 }
3933
6e48c3fe 3934 ssh_state = SSH_STATE_SESSION;
3935 if (size_needed)
3936 ssh_size();
3687d221 3937 if (eof_needed)
32874aea 3938 ssh_special(TS_EOF);
6e48c3fe 3939
7cca0d81 3940 /*
3941 * Transfer data!
3942 */
32874aea 3943 ldisc_send(NULL, 0); /* cause ldisc to notice changes */
8ccc75b0 3944 ssh_send_ok = 1;
7cca0d81 3945 while (1) {
32874aea 3946 static int try_send;
e5574168 3947 crReturnV;
32874aea 3948 try_send = FALSE;
7cca0d81 3949 if (ispkt) {
3950 if (pktin.type == SSH2_MSG_CHANNEL_DATA ||
32874aea 3951 pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA) {
3952 char *data;
3953 int length;
3954 unsigned i = ssh2_pkt_getuint32();
3955 struct ssh_channel *c;
3956 c = find234(ssh_channels, &i, ssh_channelfind);
3957 if (!c)
3958 continue; /* nonexistent channel */
3959 if (pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
3960 ssh2_pkt_getuint32() != SSH2_EXTENDED_DATA_STDERR)
3961 continue; /* extended but not stderr */
3962 ssh2_pkt_getstring(&data, &length);
3963 if (data) {
3964 switch (c->type) {
3965 case CHAN_MAINSESSION:
3966 from_backend(pktin.type ==
3967 SSH2_MSG_CHANNEL_EXTENDED_DATA, data,
3968 length);
3969 break;
3970 case CHAN_X11:
3971 x11_send(c->u.x11.s, data, length);
3972 break;
36c2a3e9 3973 case CHAN_AGENT:
32874aea 3974 while (length > 0) {
3975 if (c->u.a.lensofar < 4) {
3976 int l = min(4 - c->u.a.lensofar, length);
3977 memcpy(c->u.a.msglen + c->u.a.lensofar,
3978 data, l);
3979 data += l;
3980 length -= l;
3981 c->u.a.lensofar += l;
3982 }
3983 if (c->u.a.lensofar == 4) {
3984 c->u.a.totallen =
3985 4 + GET_32BIT(c->u.a.msglen);
3986 c->u.a.message = smalloc(c->u.a.totallen);
3987 memcpy(c->u.a.message, c->u.a.msglen, 4);
3988 }
3989 if (c->u.a.lensofar >= 4 && length > 0) {
3990 int l =
3991 min(c->u.a.totallen - c->u.a.lensofar,
3992 length);
3993 memcpy(c->u.a.message + c->u.a.lensofar,
3994 data, l);
3995 data += l;
3996 length -= l;
3997 c->u.a.lensofar += l;
3998 }
3999 if (c->u.a.lensofar == c->u.a.totallen) {
4000 void *reply, *sentreply;
4001 int replylen;
4002 agent_query(c->u.a.message,
4003 c->u.a.totallen, &reply,
4004 &replylen);
4005 if (reply)
4006 sentreply = reply;
4007 else {
4008 /* Fake SSH_AGENT_FAILURE. */
4009 sentreply = "\0\0\0\1\5";
4010 replylen = 5;
4011 }
4012 ssh2_add_channel_data(c, sentreply,
4013 replylen);
36c2a3e9 4014 try_send = TRUE;
32874aea 4015 if (reply)
4016 sfree(reply);
4017 sfree(c->u.a.message);
4018 c->u.a.lensofar = 0;
4019 }
4020 }
4021 break;
4022 }
4023 /*
4024 * Enlarge the window again at the remote
4025 * side, just in case it ever runs down and
4026 * they fail to send us any more data.
4027 */
4028 ssh2_pkt_init(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
4029 ssh2_pkt_adduint32(c->remoteid);
4030 ssh2_pkt_adduint32(length);
4031 ssh2_pkt_send();
4032 }
7cca0d81 4033 } else if (pktin.type == SSH2_MSG_DISCONNECT) {
32874aea 4034 ssh_state = SSH_STATE_CLOSED;
d211621f 4035 logevent("Received disconnect message");
32874aea 4036 crReturnV;
7cca0d81 4037 } else if (pktin.type == SSH2_MSG_CHANNEL_REQUEST) {
32874aea 4038 continue; /* exit status et al; ignore (FIXME?) */
d211621f 4039 } else if (pktin.type == SSH2_MSG_CHANNEL_EOF) {
32874aea 4040 unsigned i = ssh2_pkt_getuint32();
4041 struct ssh_channel *c;
4042
4043 c = find234(ssh_channels, &i, ssh_channelfind);
4044 if (!c)
4045 continue; /* nonexistent channel */
4046
4047 if (c->type == CHAN_X11) {
4048 /*
4049 * Remote EOF on an X11 channel means we should
4050 * wrap up and close the channel ourselves.
4051 */
4052 x11_close(c->u.x11.s);
4053 sshfwd_close(c);
4054 } else if (c->type == CHAN_AGENT) {
36c2a3e9 4055 sshfwd_close(c);
4056 }
d211621f 4057 } else if (pktin.type == SSH2_MSG_CHANNEL_CLOSE) {
32874aea 4058 unsigned i = ssh2_pkt_getuint32();
4059 struct ssh_channel *c;
4060
4061 c = find234(ssh_channels, &i, ssh_channelfind);
4062 if (!c)
4063 continue; /* nonexistent channel */
4064 if (c->closes == 0) {
4065 ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE);
4066 ssh2_pkt_adduint32(c->remoteid);
4067 ssh2_pkt_send();
4068 }
4069 /* Do pre-close processing on the channel. */
4070 switch (c->type) {
4071 case CHAN_MAINSESSION:
4072 break; /* nothing to see here, move along */
4073 case CHAN_X11:
4074 break;
4075 case CHAN_AGENT:
4076 break;
4077 }
4078 del234(ssh_channels, c);
4079 sfree(c->v2.outbuffer);
4080 sfree(c);
4081
4082 /*
4083 * See if that was the last channel left open.
4084 */
4085 if (count234(ssh_channels) == 0) {
4086 logevent("All channels closed. Disconnecting");
4087 ssh2_pkt_init(SSH2_MSG_DISCONNECT);
4088 ssh2_pkt_adduint32(SSH2_DISCONNECT_BY_APPLICATION);
4089 ssh2_pkt_addstring("All open channels closed");
4090 ssh2_pkt_addstring("en"); /* language tag */
4091 ssh2_pkt_send();
4092 ssh_state = SSH_STATE_CLOSED;
4093 crReturnV;
4094 }
4095 continue; /* remote sends close; ignore (FIXME) */
7cca0d81 4096 } else if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
32874aea 4097 unsigned i = ssh2_pkt_getuint32();
4098 struct ssh_channel *c;
4099 c = find234(ssh_channels, &i, ssh_channelfind);
4100 if (!c)
4101 continue; /* nonexistent channel */
4102 c->v2.remwindow += ssh2_pkt_getuint32();
4103 try_send = TRUE;
783415f8 4104 } else if (pktin.type == SSH2_MSG_CHANNEL_OPEN) {
32874aea 4105 char *type;
4106 int typelen;
4107 char *error = NULL;
4108 struct ssh_channel *c;
4109 ssh2_pkt_getstring(&type, &typelen);
4110 c = smalloc(sizeof(struct ssh_channel));
4111
4112 if (typelen == 3 && !memcmp(type, "x11", 3)) {
4113 if (!ssh_X11_fwd_enabled)
4114 error = "X11 forwarding is not enabled";
4115 else if (x11_init(&c->u.x11.s, cfg.x11_display, c) !=
4116 NULL) {
4117 error = "Unable to open an X11 connection";
4118 } else {
4119 c->type = CHAN_X11;
4120 }
4121 } else if (typelen == 22 &&
36c2a3e9 4122 !memcmp(type, "auth-agent@openssh.com", 3)) {
32874aea 4123 if (!ssh_agentfwd_enabled)
4124 error = "Agent forwarding is not enabled";
36c2a3e9 4125 else {
32874aea 4126 c->type = CHAN_AGENT; /* identify channel type */
36c2a3e9 4127 c->u.a.lensofar = 0;
32874aea 4128 }
4129 } else {
4130 error = "Unsupported channel type requested";
4131 }
4132
4133 c->remoteid = ssh2_pkt_getuint32();
4134 if (error) {
4135 ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_FAILURE);
4136 ssh2_pkt_adduint32(c->remoteid);
4137 ssh2_pkt_adduint32(SSH2_OPEN_CONNECT_FAILED);
4138 ssh2_pkt_addstring(error);
4139 ssh2_pkt_addstring("en"); /* language tag */
4140 ssh2_pkt_send();
4141 sfree(c);
4142 } else {
4143 c->localid = alloc_channel_id();
4144 c->closes = 0;
4145 c->v2.remwindow = ssh2_pkt_getuint32();
4146 c->v2.remmaxpkt = ssh2_pkt_getuint32();
4147 c->v2.outbuffer = NULL;
4148 c->v2.outbuflen = c->v2.outbufsize = 0;
4149 add234(ssh_channels, c);
4150 ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
4151 ssh2_pkt_adduint32(c->remoteid);
4152 ssh2_pkt_adduint32(c->localid);
4153 ssh2_pkt_adduint32(0x8000UL); /* our window size */
4154 ssh2_pkt_adduint32(0x4000UL); /* our max pkt size */
4155 ssh2_pkt_send();
4156 }
7cca0d81 4157 } else {
8d5de777 4158 bombout(("Strange packet received: type %d", pktin.type));
32874aea 4159 crReturnV;
7cca0d81 4160 }
4161 } else {
32874aea 4162 /*
4163 * We have spare data. Add it to the channel buffer.
4164 */
4165 ssh2_add_channel_data(mainchan, in, inlen);
4166 try_send = TRUE;
4167 }
4168 if (try_send) {
4169 int i;
4170 struct ssh_channel *c;
4171 /*
4172 * Try to send data on all channels if we can.
4173 */
4174 for (i = 0; NULL != (c = index234(ssh_channels, i)); i++)
4175 ssh2_try_send(c);
7cca0d81 4176 }
e5574168 4177 }
4178
4179 crFinishV;
4180}
4181
4182/*
7cca0d81 4183 * Handle the top-level SSH2 protocol.
4184 */
4185static void ssh2_protocol(unsigned char *in, int inlen, int ispkt)
4186{
4187 if (do_ssh2_transport(in, inlen, ispkt) == 0)
32874aea 4188 return;
7cca0d81 4189 do_ssh2_authconn(in, inlen, ispkt);
4190}
4191
4192/*
8df7a775 4193 * Called to set up the connection.
374330e2 4194 *
4195 * Returns an error message, or NULL on success.
374330e2 4196 */
32874aea 4197static char *ssh_init(char *host, int port, char **realhost)
4198{
fb09bf1c 4199 char *p;
32874aea 4200
8f203108 4201#ifdef MSCRYPTOAPI
32874aea 4202 if (crypto_startup() == 0)
8f203108 4203 return "Microsoft high encryption pack not installed!";
4204#endif
374330e2 4205
8df7a775 4206 ssh_send_ok = 0;
0965bee0 4207 ssh_editing = 0;
4208 ssh_echoing = 0;
8df7a775 4209
fb09bf1c 4210 p = connect_to_host(host, port, realhost);
4211 if (p != NULL)
4212 return p;
374330e2 4213
374330e2 4214 return NULL;
4215}
4216
4217/*
374330e2 4218 * Called to send data down the Telnet connection.
4219 */
32874aea 4220static void ssh_send(char *buf, int len)
4221{
f78051a1 4222 if (s == NULL || ssh_protocol == NULL)
374330e2 4223 return;
4224
4225 ssh_protocol(buf, len, 0);
4226}
4227
4228/*
6e48c3fe 4229 * Called to set the size of the window from SSH's POV.
374330e2 4230 */
32874aea 4231static void ssh_size(void)
4232{
374330e2 4233 switch (ssh_state) {
4234 case SSH_STATE_BEFORE_SIZE:
3687d221 4235 case SSH_STATE_PREPACKET:
21248260 4236 case SSH_STATE_CLOSED:
374330e2 4237 break; /* do nothing */
4238 case SSH_STATE_INTERMED:
4239 size_needed = TRUE; /* buffer for later */
4240 break;
4241 case SSH_STATE_SESSION:
32874aea 4242 if (!cfg.nopty) {
4243 if (ssh_version == 1) {
4244 send_packet(SSH1_CMSG_WINDOW_SIZE,
4245 PKT_INT, rows, PKT_INT, cols,
4246 PKT_INT, 0, PKT_INT, 0, PKT_END);
4247 } else {
4248 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
4249 ssh2_pkt_adduint32(mainchan->remoteid);
4250 ssh2_pkt_addstring("window-change");
4251 ssh2_pkt_addbool(0);
4252 ssh2_pkt_adduint32(cols);
4253 ssh2_pkt_adduint32(rows);
4254 ssh2_pkt_adduint32(0);
4255 ssh2_pkt_adduint32(0);
4256 ssh2_pkt_send();
4257 }
4258 }
4259 break;
374330e2 4260 }
4261}
4262
4263/*
6abbf9e3 4264 * Send Telnet special codes. TS_EOF is useful for `plink', so you
4265 * can send an EOF and collect resulting output (e.g. `plink
4266 * hostname sort').
374330e2 4267 */
32874aea 4268static void ssh_special(Telnet_Special code)
4269{
6abbf9e3 4270 if (code == TS_EOF) {
32874aea 4271 if (ssh_state != SSH_STATE_SESSION) {
4272 /*
4273 * Buffer the EOF in case we are pre-SESSION, so we can
4274 * send it as soon as we reach SESSION.
4275 */
4276 if (code == TS_EOF)
4277 eof_needed = TRUE;
4278 return;
4279 }
4280 if (ssh_version == 1) {
4281 send_packet(SSH1_CMSG_EOF, PKT_END);
4282 } else {
4283 ssh2_pkt_init(SSH2_MSG_CHANNEL_EOF);
4284 ssh2_pkt_adduint32(mainchan->remoteid);
4285 ssh2_pkt_send();
4286 }
4287 logevent("Sent EOF message");
ec55b220 4288 } else if (code == TS_PING) {
32874aea 4289 if (ssh_state == SSH_STATE_CLOSED
4290 || ssh_state == SSH_STATE_PREPACKET) return;
4291 if (ssh_version == 1) {
4292 send_packet(SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
4293 } else {
4294 ssh2_pkt_init(SSH2_MSG_IGNORE);
4295 ssh2_pkt_addstring_start();
4296 ssh2_pkt_send();
4297 }
6abbf9e3 4298 } else {
32874aea 4299 /* do nothing */
6abbf9e3 4300 }
374330e2 4301}
4302
32874aea 4303static Socket ssh_socket(void)
4304{
4305 return s;
4306}
8ccc75b0 4307
32874aea 4308static int ssh_sendok(void)
4309{
4310 return ssh_send_ok;
4311}
fb09bf1c 4312
32874aea 4313static int ssh_ldisc(int option)
4314{
4315 if (option == LD_ECHO)
4316 return ssh_echoing;
4317 if (option == LD_EDIT)
4318 return ssh_editing;
0965bee0 4319 return FALSE;
4320}
4321
374330e2 4322Backend ssh_backend = {
4323 ssh_init,
374330e2 4324 ssh_send,
4325 ssh_size,
4017be6d 4326 ssh_special,
8ccc75b0 4327 ssh_socket,
97db3be4 4328 ssh_sendok,
0965bee0 4329 ssh_ldisc,
97db3be4 4330 22
374330e2 4331};
Local modifications for Simon Tatham's `PuTTY' SSH client and terminal emulator