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plink can now execute a specific command instead of just a shell session
[u/mdw/putty] / ssh.c
CommitLineData
374330e2 1#include <stdio.h>
2#include <stdlib.h>
fb09bf1c 3#include <stdarg.h>
4#include <assert.h>
374330e2 5#include <winsock.h>
6
7#include "putty.h"
fb09bf1c 8#include "ssh.h"
9#include "scp.h"
374330e2 10
11#ifndef FALSE
12#define FALSE 0
13#endif
14#ifndef TRUE
15#define TRUE 1
16#endif
17
fb09bf1c 18#define logevent(s) { logevent(s); \
4017be6d 19 if (!(flags & FLAG_CONNECTION) && (flags & FLAG_VERBOSE)) \
fb09bf1c 20 fprintf(stderr, "%s\n", s); }
21
e5574168 22#define SSH1_MSG_DISCONNECT 1
23#define SSH1_SMSG_PUBLIC_KEY 2
24#define SSH1_CMSG_SESSION_KEY 3
25#define SSH1_CMSG_USER 4
7cca0d81 26#define SSH1_CMSG_AUTH_RSA 6
27#define SSH1_SMSG_AUTH_RSA_CHALLENGE 7
28#define SSH1_CMSG_AUTH_RSA_RESPONSE 8
e5574168 29#define SSH1_CMSG_AUTH_PASSWORD 9
30#define SSH1_CMSG_REQUEST_PTY 10
31#define SSH1_CMSG_WINDOW_SIZE 11
32#define SSH1_CMSG_EXEC_SHELL 12
33#define SSH1_CMSG_EXEC_CMD 13
34#define SSH1_SMSG_SUCCESS 14
35#define SSH1_SMSG_FAILURE 15
36#define SSH1_CMSG_STDIN_DATA 16
37#define SSH1_SMSG_STDOUT_DATA 17
38#define SSH1_SMSG_STDERR_DATA 18
39#define SSH1_CMSG_EOF 19
40#define SSH1_SMSG_EXIT_STATUS 20
41#define SSH1_CMSG_EXIT_CONFIRMATION 33
42#define SSH1_MSG_IGNORE 32
43#define SSH1_MSG_DEBUG 36
44#define SSH1_CMSG_AUTH_TIS 39
45#define SSH1_SMSG_AUTH_TIS_CHALLENGE 40
46#define SSH1_CMSG_AUTH_TIS_RESPONSE 41
47
48#define SSH1_AUTH_TIS 5
49
50#define SSH2_MSG_DISCONNECT 1
51#define SSH2_MSG_IGNORE 2
52#define SSH2_MSG_UNIMPLEMENTED 3
53#define SSH2_MSG_DEBUG 4
54#define SSH2_MSG_SERVICE_REQUEST 5
55#define SSH2_MSG_SERVICE_ACCEPT 6
56#define SSH2_MSG_KEXINIT 20
57#define SSH2_MSG_NEWKEYS 21
58#define SSH2_MSG_KEXDH_INIT 30
59#define SSH2_MSG_KEXDH_REPLY 31
7cca0d81 60#define SSH2_MSG_USERAUTH_REQUEST 50
61#define SSH2_MSG_USERAUTH_FAILURE 51
62#define SSH2_MSG_USERAUTH_SUCCESS 52
63#define SSH2_MSG_USERAUTH_BANNER 53
64#define SSH2_MSG_USERAUTH_PK_OK 60
65#define SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ 60
66#define SSH2_MSG_GLOBAL_REQUEST 80
67#define SSH2_MSG_REQUEST_SUCCESS 81
68#define SSH2_MSG_REQUEST_FAILURE 82
69#define SSH2_MSG_CHANNEL_OPEN 90
70#define SSH2_MSG_CHANNEL_OPEN_CONFIRMATION 91
71#define SSH2_MSG_CHANNEL_OPEN_FAILURE 92
72#define SSH2_MSG_CHANNEL_WINDOW_ADJUST 93
73#define SSH2_MSG_CHANNEL_DATA 94
74#define SSH2_MSG_CHANNEL_EXTENDED_DATA 95
75#define SSH2_MSG_CHANNEL_EOF 96
76#define SSH2_MSG_CHANNEL_CLOSE 97
77#define SSH2_MSG_CHANNEL_REQUEST 98
78#define SSH2_MSG_CHANNEL_SUCCESS 99
79#define SSH2_MSG_CHANNEL_FAILURE 100
80
81#define SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED 1
82#define SSH2_OPEN_CONNECT_FAILED 2
83#define SSH2_OPEN_UNKNOWN_CHANNEL_TYPE 3
84#define SSH2_OPEN_RESOURCE_SHORTAGE 4
85#define SSH2_EXTENDED_DATA_STDERR 1
fb09bf1c 86
87#define GET_32BIT(cp) \
88 (((unsigned long)(unsigned char)(cp)[0] << 24) | \
89 ((unsigned long)(unsigned char)(cp)[1] << 16) | \
90 ((unsigned long)(unsigned char)(cp)[2] << 8) | \
91 ((unsigned long)(unsigned char)(cp)[3]))
92
93#define PUT_32BIT(cp, value) { \
94 (cp)[0] = (unsigned char)((value) >> 24); \
95 (cp)[1] = (unsigned char)((value) >> 16); \
96 (cp)[2] = (unsigned char)((value) >> 8); \
97 (cp)[3] = (unsigned char)(value); }
98
7cca0d81 99enum { PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR, PKT_BIGNUM };
972a41c8 100
374330e2 101/* Coroutine mechanics for the sillier bits of the code */
102#define crBegin1 static int crLine = 0;
103#define crBegin2 switch(crLine) { case 0:;
104#define crBegin crBegin1; crBegin2;
105#define crFinish(z) } crLine = 0; return (z)
106#define crFinishV } crLine = 0; return
107#define crReturn(z) \
108 do {\
109 crLine=__LINE__; return (z); case __LINE__:;\
110 } while (0)
111#define crReturnV \
112 do {\
113 crLine=__LINE__; return; case __LINE__:;\
114 } while (0)
115#define crStop(z) do{ crLine = 0; return (z); }while(0)
116#define crStopV do{ crLine = 0; return; }while(0)
fb09bf1c 117#define crWaitUntil(c) do { crReturn(0); } while (!(c))
7cca0d81 118#define crWaitUntilV(c) do { crReturnV; } while (!(c))
374330e2 119
e5574168 120extern struct ssh_cipher ssh_3des;
033b4cef 121extern struct ssh_cipher ssh_3des_ssh2;
e5574168 122extern struct ssh_cipher ssh_des;
123extern struct ssh_cipher ssh_blowfish;
124
125/* for ssh 2; we miss out single-DES because it isn't supported */
033b4cef 126struct ssh_cipher *ciphers[] = { &ssh_3des_ssh2, &ssh_blowfish };
e5574168 127
128extern struct ssh_kex ssh_diffiehellman;
129struct ssh_kex *kex_algs[] = { &ssh_diffiehellman };
130
131extern struct ssh_hostkey ssh_dss;
132struct ssh_hostkey *hostkey_algs[] = { &ssh_dss };
133
134extern struct ssh_mac ssh_sha1;
135
136SHA_State exhash;
137
d39f364a 138static void nullmac_key(unsigned char *key) { }
e5574168 139static void nullmac_generate(unsigned char *blk, int len, unsigned long seq) { }
140static int nullmac_verify(unsigned char *blk, int len, unsigned long seq) { return 1; }
141struct ssh_mac ssh_mac_none = {
d39f364a 142 nullmac_key, nullmac_key, nullmac_generate, nullmac_verify, "none", 0
e5574168 143};
144struct ssh_mac *macs[] = { &ssh_sha1, &ssh_mac_none };
145
146struct ssh_compress ssh_comp_none = {
147 "none"
148};
149struct ssh_compress *compressions[] = { &ssh_comp_none };
150
374330e2 151static SOCKET s = INVALID_SOCKET;
152
153static unsigned char session_key[32];
154static struct ssh_cipher *cipher = NULL;
e5574168 155static struct ssh_cipher *cscipher = NULL;
156static struct ssh_cipher *sccipher = NULL;
157static struct ssh_mac *csmac = NULL;
158static struct ssh_mac *scmac = NULL;
159static struct ssh_compress *cscomp = NULL;
160static struct ssh_compress *sccomp = NULL;
161static struct ssh_kex *kex = NULL;
162static struct ssh_hostkey *hostkey = NULL;
85ee8208 163int (*ssh_get_password)(const char *prompt, char *str, int maxlen) = NULL;
374330e2 164
165static char *savedhost;
166
167static enum {
168 SSH_STATE_BEFORE_SIZE,
169 SSH_STATE_INTERMED,
21248260 170 SSH_STATE_SESSION,
171 SSH_STATE_CLOSED
374330e2 172} ssh_state = SSH_STATE_BEFORE_SIZE;
173
174static int size_needed = FALSE;
175
176static void s_write (char *buf, int len) {
177 while (len > 0) {
178 int i = send (s, buf, len, 0);
4017be6d 179 noise_ultralight(i);
180 if (i <= 0)
181 fatalbox("Lost connection while sending");
374330e2 182 if (i > 0)
183 len -= i, buf += i;
184 }
185}
186
187static int s_read (char *buf, int len) {
188 int ret = 0;
189 while (len > 0) {
190 int i = recv (s, buf, len, 0);
4017be6d 191 noise_ultralight(i);
374330e2 192 if (i > 0)
193 len -= i, buf += i, ret += i;
194 else
195 return i;
196 }
197 return ret;
198}
199
200static void c_write (char *buf, int len) {
4017be6d 201 if (!(flags & FLAG_CONNECTION)) {
202 int i;
203 for (i = 0; i < len; i++)
204 if (buf[i] != '\r')
205 fputc(buf[i], stderr);
fb09bf1c 206 return;
207 }
c9def1b8 208 while (len--)
209 c_write1(*buf++);
374330e2 210}
211
212struct Packet {
213 long length;
214 int type;
374330e2 215 unsigned char *data;
216 unsigned char *body;
e5574168 217 long savedpos;
374330e2 218 long maxlen;
219};
220
fb09bf1c 221static struct Packet pktin = { 0, 0, NULL, NULL, 0 };
222static struct Packet pktout = { 0, 0, NULL, NULL, 0 };
374330e2 223
6abbf9e3 224static int ssh_version;
e5574168 225static void (*ssh_protocol)(unsigned char *in, int inlen, int ispkt);
226static void ssh1_protocol(unsigned char *in, int inlen, int ispkt);
227static void ssh2_protocol(unsigned char *in, int inlen, int ispkt);
374330e2 228static void ssh_size(void);
229
e5574168 230static int (*s_rdpkt)(unsigned char **data, int *datalen);
fb09bf1c 231
232/*
233 * Collect incoming data in the incoming packet buffer.
e5574168 234 * Decipher and verify the packet when it is completely read.
235 * Drop SSH1_MSG_DEBUG and SSH1_MSG_IGNORE packets.
fb09bf1c 236 * Update the *data and *datalen variables.
237 * Return the additional nr of bytes needed, or 0 when
238 * a complete packet is available.
239 */
e5574168 240static int ssh1_rdpkt(unsigned char **data, int *datalen)
fb09bf1c 241{
242 static long len, pad, biglen, to_read;
572f871e 243 static unsigned long realcrc, gotcrc;
fb09bf1c 244 static unsigned char *p;
245 static int i;
374330e2 246
247 crBegin;
374330e2 248
fb09bf1c 249next_packet:
37508af4 250
fb09bf1c 251 pktin.type = 0;
252 pktin.length = 0;
374330e2 253
fb09bf1c 254 for (i = len = 0; i < 4; i++) {
255 while ((*datalen) == 0)
256 crReturn(4-i);
257 len = (len << 8) + **data;
258 (*data)++, (*datalen)--;
259 }
374330e2 260
fb09bf1c 261#ifdef FWHACK
262 if (len == 0x52656d6f) { /* "Remo"te server has closed ... */
263 len = 0x300; /* big enough to carry to end */
264 }
265#endif
374330e2 266
fb09bf1c 267 pad = 8 - (len % 8);
268 biglen = len + pad;
269 pktin.length = len - 5;
270
271 if (pktin.maxlen < biglen) {
272 pktin.maxlen = biglen;
e5574168 273 pktin.data = (pktin.data == NULL ? malloc(biglen+APIEXTRA) :
274 realloc(pktin.data, biglen+APIEXTRA));
fb09bf1c 275 if (!pktin.data)
276 fatalbox("Out of memory");
277 }
374330e2 278
fb09bf1c 279 to_read = biglen;
280 p = pktin.data;
281 while (to_read > 0) {
282 static int chunk;
283 chunk = to_read;
284 while ((*datalen) == 0)
285 crReturn(to_read);
286 if (chunk > (*datalen))
287 chunk = (*datalen);
288 memcpy(p, *data, chunk);
289 *data += chunk;
290 *datalen -= chunk;
291 p += chunk;
292 to_read -= chunk;
293 }
374330e2 294
fb09bf1c 295 if (cipher)
296 cipher->decrypt(pktin.data, biglen);
374330e2 297
fb09bf1c 298 pktin.type = pktin.data[pad];
299 pktin.body = pktin.data + pad + 1;
374330e2 300
fb09bf1c 301 realcrc = crc32(pktin.data, biglen-4);
302 gotcrc = GET_32BIT(pktin.data+biglen-4);
303 if (gotcrc != realcrc) {
304 fatalbox("Incorrect CRC received on packet");
305 }
572f871e 306
e5574168 307 if (pktin.type == SSH1_SMSG_STDOUT_DATA ||
308 pktin.type == SSH1_SMSG_STDERR_DATA ||
309 pktin.type == SSH1_MSG_DEBUG ||
310 pktin.type == SSH1_SMSG_AUTH_TIS_CHALLENGE) {
fb09bf1c 311 long strlen = GET_32BIT(pktin.body);
312 if (strlen + 4 != pktin.length)
313 fatalbox("Received data packet with bogus string length");
314 }
315
e5574168 316 if (pktin.type == SSH1_MSG_DEBUG) {
fb09bf1c 317 /* log debug message */
318 char buf[80];
319 int strlen = GET_32BIT(pktin.body);
320 strcpy(buf, "Remote: ");
321 if (strlen > 70) strlen = 70;
322 memcpy(buf+8, pktin.body+4, strlen);
323 buf[8+strlen] = '\0';
324 logevent(buf);
325 goto next_packet;
e5574168 326 } else if (pktin.type == SSH1_MSG_IGNORE) {
fb09bf1c 327 /* do nothing */
328 goto next_packet;
329 }
330
331 crFinish(0);
332}
333
e5574168 334static int ssh2_rdpkt(unsigned char **data, int *datalen)
335{
336 static long len, pad, payload, packetlen, maclen;
337 static int i;
338 static int cipherblk;
339 static unsigned long incoming_sequence = 0;
340
341 crBegin;
342
343next_packet:
344
345 pktin.type = 0;
346 pktin.length = 0;
347
348 if (cipher)
349 cipherblk = cipher->blksize;
350 else
351 cipherblk = 8;
352 if (cipherblk < 8)
353 cipherblk = 8;
354
355 if (pktin.maxlen < cipherblk) {
356 pktin.maxlen = cipherblk;
357 pktin.data = (pktin.data == NULL ? malloc(cipherblk+APIEXTRA) :
358 realloc(pktin.data, cipherblk+APIEXTRA));
359 if (!pktin.data)
360 fatalbox("Out of memory");
361 }
362
363 /*
364 * Acquire and decrypt the first block of the packet. This will
365 * contain the length and padding details.
366 */
367 for (i = len = 0; i < cipherblk; i++) {
368 while ((*datalen) == 0)
369 crReturn(cipherblk-i);
370 pktin.data[i] = *(*data)++;
371 (*datalen)--;
372 }
373#ifdef FWHACK
374 if (!memcmp(pktin.data, "Remo", 4)) {/* "Remo"te server has closed ... */
375 /* FIXME */
376 }
377#endif
378 if (sccipher)
379 sccipher->decrypt(pktin.data, cipherblk);
380
381 /*
382 * Now get the length and padding figures.
383 */
384 len = GET_32BIT(pktin.data);
385 pad = pktin.data[4];
386
387 /*
388 * This enables us to deduce the payload length.
389 */
390 payload = len - pad - 1;
391
392 pktin.length = payload + 5;
393
394 /*
395 * So now we can work out the total packet length.
396 */
397 packetlen = len + 4;
398 maclen = scmac ? scmac->len : 0;
399
400 /*
401 * Adjust memory allocation if packet is too big.
402 */
403 if (pktin.maxlen < packetlen) {
404 pktin.maxlen = packetlen;
405 pktin.data = (pktin.data == NULL ? malloc(packetlen+APIEXTRA) :
406 realloc(pktin.data, packetlen+APIEXTRA));
407 if (!pktin.data)
408 fatalbox("Out of memory");
409 }
410
411 /*
412 * Read and decrypt the remainder of the packet.
413 */
414 for (i = cipherblk; i < packetlen + maclen; i++) {
415 while ((*datalen) == 0)
416 crReturn(packetlen + maclen - i);
417 pktin.data[i] = *(*data)++;
418 (*datalen)--;
419 }
420 /* Decrypt everything _except_ the MAC. */
421 if (sccipher)
422 sccipher->decrypt(pktin.data + cipherblk, packetlen - cipherblk);
423
7cca0d81 424#if 0
d39f364a 425 debug(("Got packet len=%d pad=%d\r\n", len, pad));
426 for (i = 0; i < packetlen; i++)
427 debug((" %02x", (unsigned char)pktin.data[i]));
428 debug(("\r\n"));
7cca0d81 429#endif
d39f364a 430
e5574168 431 /*
432 * Check the MAC.
433 */
033b4cef 434 if (scmac && !scmac->verify(pktin.data, len+4, incoming_sequence))
e5574168 435 fatalbox("Incorrect MAC received on packet");
033b4cef 436 incoming_sequence++; /* whether or not we MACed */
e5574168 437
438 pktin.savedpos = 6;
439 pktin.type = pktin.data[5];
e5574168 440
7cca0d81 441 if (pktin.type == SSH2_MSG_IGNORE || pktin.type == SSH2_MSG_DEBUG)
442 goto next_packet; /* FIXME: print DEBUG message */
e5574168 443
444 crFinish(0);
445}
446
fb09bf1c 447static void ssh_gotdata(unsigned char *data, int datalen)
448{
449 while (datalen > 0) {
85ee8208 450 if ( s_rdpkt(&data, &datalen) == 0 ) {
374330e2 451 ssh_protocol(NULL, 0, 1);
85ee8208 452 if (ssh_state == SSH_STATE_CLOSED) {
453 return;
454 }
455 }
374330e2 456 }
374330e2 457}
458
fb09bf1c 459
374330e2 460static void s_wrpkt_start(int type, int len) {
461 int pad, biglen;
462
463 len += 5; /* type and CRC */
464 pad = 8 - (len%8);
465 biglen = len + pad;
466
467 pktout.length = len-5;
468 if (pktout.maxlen < biglen) {
469 pktout.maxlen = biglen;
8f203108 470#ifdef MSCRYPTOAPI
fb09bf1c 471 /* Allocate enough buffer space for extra block
8f203108 472 * for MS CryptEncrypt() */
fb09bf1c 473 pktout.data = (pktout.data == NULL ? malloc(biglen+12) :
474 realloc(pktout.data, biglen+12));
8f203108 475#else
c1f5f956 476 pktout.data = (pktout.data == NULL ? malloc(biglen+4) :
477 realloc(pktout.data, biglen+4));
8f203108 478#endif
374330e2 479 if (!pktout.data)
480 fatalbox("Out of memory");
481 }
482
483 pktout.type = type;
484 pktout.body = pktout.data+4+pad+1;
485}
486
487static void s_wrpkt(void) {
488 int pad, len, biglen, i;
489 unsigned long crc;
490
491 len = pktout.length + 5; /* type and CRC */
492 pad = 8 - (len%8);
493 biglen = len + pad;
494
495 pktout.body[-1] = pktout.type;
496 for (i=0; i<pad; i++)
497 pktout.data[i+4] = random_byte();
498 crc = crc32(pktout.data+4, biglen-4);
fb09bf1c 499 PUT_32BIT(pktout.data+biglen, crc);
500 PUT_32BIT(pktout.data, len);
374330e2 501
502 if (cipher)
503 cipher->encrypt(pktout.data+4, biglen);
504
505 s_write(pktout.data, biglen+4);
506}
507
fb09bf1c 508/*
509 * Construct a packet with the specified contents and
510 * send it to the server.
511 */
512static void send_packet(int pkttype, ...)
513{
514 va_list args;
515 unsigned char *p, *argp, argchar;
516 unsigned long argint;
517 int pktlen, argtype, arglen;
7cca0d81 518 Bignum bn;
519 int i;
fb09bf1c 520
521 pktlen = 0;
522 va_start(args, pkttype);
523 while ((argtype = va_arg(args, int)) != PKT_END) {
524 switch (argtype) {
525 case PKT_INT:
526 (void) va_arg(args, int);
527 pktlen += 4;
528 break;
529 case PKT_CHAR:
530 (void) va_arg(args, char);
531 pktlen++;
532 break;
533 case PKT_DATA:
534 (void) va_arg(args, unsigned char *);
535 arglen = va_arg(args, int);
536 pktlen += arglen;
537 break;
538 case PKT_STR:
539 argp = va_arg(args, unsigned char *);
540 arglen = strlen(argp);
541 pktlen += 4 + arglen;
542 break;
7cca0d81 543 case PKT_BIGNUM:
544 bn = va_arg(args, Bignum);
545 i = 16 * bn[0] - 1;
546 while ( i > 0 && (bn[i/16+1] >> (i%16)) == 0 )
547 i--;
548 pktlen += 2 + (i+7)/8;
549 break;
fb09bf1c 550 default:
551 assert(0);
552 }
553 }
554 va_end(args);
555
556 s_wrpkt_start(pkttype, pktlen);
557 p = pktout.body;
558
559 va_start(args, pkttype);
560 while ((argtype = va_arg(args, int)) != PKT_END) {
561 switch (argtype) {
562 case PKT_INT:
563 argint = va_arg(args, int);
564 PUT_32BIT(p, argint);
565 p += 4;
566 break;
567 case PKT_CHAR:
568 argchar = va_arg(args, unsigned char);
569 *p = argchar;
570 p++;
571 break;
572 case PKT_DATA:
573 argp = va_arg(args, unsigned char *);
574 arglen = va_arg(args, int);
575 memcpy(p, argp, arglen);
576 p += arglen;
577 break;
578 case PKT_STR:
579 argp = va_arg(args, unsigned char *);
580 arglen = strlen(argp);
581 PUT_32BIT(p, arglen);
582 memcpy(p + 4, argp, arglen);
583 p += 4 + arglen;
584 break;
7cca0d81 585 case PKT_BIGNUM:
586 bn = va_arg(args, Bignum);
587 i = 16 * bn[0] - 1;
588 while ( i > 0 && (bn[i/16+1] >> (i%16)) == 0 )
589 i--;
590 *p++ = (i >> 8) & 0xFF;
591 *p++ = i & 0xFF;
592 i = (i + 7) / 8;
593 while (i-- > 0) {
594 if (i % 2)
595 *p++ = bn[i/2+1] >> 8;
596 else
597 *p++ = bn[i/2+1] & 0xFF;
598 }
599 break;
fb09bf1c 600 }
601 }
602 va_end(args);
603
604 s_wrpkt();
605}
606
607
608/*
609 * Connect to specified host and port.
610 * Returns an error message, or NULL on success.
611 * Also places the canonical host name into `realhost'.
612 */
613static char *connect_to_host(char *host, int port, char **realhost)
614{
615 SOCKADDR_IN addr;
616 struct hostent *h;
617 unsigned long a;
618#ifdef FWHACK
619 char *FWhost;
620 int FWport;
621#endif
622
623 savedhost = malloc(1+strlen(host));
624 if (!savedhost)
625 fatalbox("Out of memory");
626 strcpy(savedhost, host);
627
628 if (port < 0)
629 port = 22; /* default ssh port */
630
631#ifdef FWHACK
632 FWhost = host;
633 FWport = port;
634 host = FWSTR;
635 port = 23;
636#endif
637
638 /*
639 * Try to find host.
640 */
641 if ( (a = inet_addr(host)) == (unsigned long) INADDR_NONE) {
642 if ( (h = gethostbyname(host)) == NULL)
643 switch (WSAGetLastError()) {
644 case WSAENETDOWN: return "Network is down";
645 case WSAHOST_NOT_FOUND: case WSANO_DATA:
646 return "Host does not exist";
647 case WSATRY_AGAIN: return "Host not found";
648 default: return "gethostbyname: unknown error";
649 }
650 memcpy (&a, h->h_addr, sizeof(a));
651 *realhost = h->h_name;
652 } else
653 *realhost = host;
654#ifdef FWHACK
655 *realhost = FWhost;
656#endif
657 a = ntohl(a);
658
659 /*
660 * Open socket.
661 */
662 s = socket(AF_INET, SOCK_STREAM, 0);
663 if (s == INVALID_SOCKET)
664 switch (WSAGetLastError()) {
665 case WSAENETDOWN: return "Network is down";
666 case WSAEAFNOSUPPORT: return "TCP/IP support not present";
667 default: return "socket(): unknown error";
668 }
669
670 /*
671 * Bind to local address.
672 */
673 addr.sin_family = AF_INET;
674 addr.sin_addr.s_addr = htonl(INADDR_ANY);
675 addr.sin_port = htons(0);
676 if (bind (s, (struct sockaddr *)&addr, sizeof(addr)) == SOCKET_ERROR)
677 switch (WSAGetLastError()) {
678 case WSAENETDOWN: return "Network is down";
679 default: return "bind(): unknown error";
680 }
681
682 /*
683 * Connect to remote address.
684 */
685 addr.sin_addr.s_addr = htonl(a);
686 addr.sin_port = htons((short)port);
687 if (connect (s, (struct sockaddr *)&addr, sizeof(addr)) == SOCKET_ERROR)
688 switch (WSAGetLastError()) {
689 case WSAENETDOWN: return "Network is down";
690 case WSAECONNREFUSED: return "Connection refused";
691 case WSAENETUNREACH: return "Network is unreachable";
692 case WSAEHOSTUNREACH: return "No route to host";
693 default: return "connect(): unknown error";
694 }
695
696#ifdef FWHACK
697 send(s, "connect ", 8, 0);
698 send(s, FWhost, strlen(FWhost), 0);
699 {
700 char buf[20];
701 sprintf(buf, " %d\n", FWport);
702 send (s, buf, strlen(buf), 0);
703 }
704#endif
705
706 return NULL;
707}
708
9697bfd2 709static int ssh_versioncmp(char *a, char *b) {
710 char *ae, *be;
711 unsigned long av, bv;
712
43aa02a7 713 av = strtoul(a, &ae, 10);
714 bv = strtoul(b, &be, 10);
9697bfd2 715 if (av != bv) return (av < bv ? -1 : +1);
716 if (*ae == '.') ae++;
717 if (*be == '.') be++;
43aa02a7 718 av = strtoul(ae, &ae, 10);
719 bv = strtoul(be, &be, 10);
9697bfd2 720 if (av != bv) return (av < bv ? -1 : +1);
721 return 0;
722}
723
e5574168 724
725/*
726 * Utility routine for putting an SSH-protocol `string' into a SHA
727 * state.
728 */
729#include <stdio.h>
730void sha_string(SHA_State *s, void *str, int len) {
731 unsigned char lenblk[4];
732static FILE *fp;
733 PUT_32BIT(lenblk, len);
734if (!fp) fp = fopen("h:\\statham\\windows\\putty\\data","wb");
735fwrite(lenblk, 4, 1, fp);
736 SHA_Bytes(s, lenblk, 4);
737fwrite(str, len, 1, fp);
738fflush(fp);
739 SHA_Bytes(s, str, len);
740}
741
7cca0d81 742/*
743 * SSH2 packet construction functions.
744 */
745void ssh2_pkt_adddata(void *data, int len) {
746 pktout.length += len;
747 if (pktout.maxlen < pktout.length) {
748 pktout.maxlen = pktout.length + 256;
749 pktout.data = (pktout.data == NULL ? malloc(pktout.maxlen+APIEXTRA) :
750 realloc(pktout.data, pktout.maxlen+APIEXTRA));
751 if (!pktout.data)
752 fatalbox("Out of memory");
753 }
754 memcpy(pktout.data+pktout.length-len, data, len);
755}
756void ssh2_pkt_addbyte(unsigned char byte) {
757 ssh2_pkt_adddata(&byte, 1);
758}
759void ssh2_pkt_init(int pkt_type) {
760 pktout.length = 5;
761 ssh2_pkt_addbyte((unsigned char)pkt_type);
762}
763void ssh2_pkt_addbool(unsigned char value) {
764 ssh2_pkt_adddata(&value, 1);
765}
766void ssh2_pkt_adduint32(unsigned long value) {
767 unsigned char x[4];
768 PUT_32BIT(x, value);
769 ssh2_pkt_adddata(x, 4);
770}
771void ssh2_pkt_addstring_start(void) {
772 ssh2_pkt_adduint32(0);
773 pktout.savedpos = pktout.length;
774}
775void ssh2_pkt_addstring_str(char *data) {
776 ssh2_pkt_adddata(data, strlen(data));
777 PUT_32BIT(pktout.data + pktout.savedpos - 4,
778 pktout.length - pktout.savedpos);
779}
780void ssh2_pkt_addstring_data(char *data, int len) {
781 ssh2_pkt_adddata(data, len);
782 PUT_32BIT(pktout.data + pktout.savedpos - 4,
783 pktout.length - pktout.savedpos);
784}
785void ssh2_pkt_addstring(char *data) {
786 ssh2_pkt_addstring_start();
787 ssh2_pkt_addstring_str(data);
788}
789char *ssh2_mpint_fmt(Bignum b, int *len) {
790 unsigned char *p;
791 int i, n = b[0];
792 p = malloc(n * 2 + 1);
793 if (!p)
794 fatalbox("out of memory");
795 p[0] = 0;
796 for (i = 0; i < n; i++) {
797 p[i*2+1] = (b[n-i] >> 8) & 0xFF;
798 p[i*2+2] = (b[n-i] ) & 0xFF;
799 }
800 i = 0;
801 while (p[i] == 0 && (p[i+1] & 0x80) == 0)
802 i++;
803 memmove(p, p+i, n*2+1-i);
804 *len = n*2+1-i;
805 return p;
806}
807void ssh2_pkt_addmp(Bignum b) {
808 unsigned char *p;
809 int len;
810 p = ssh2_mpint_fmt(b, &len);
811 ssh2_pkt_addstring_start();
812 ssh2_pkt_addstring_data(p, len);
813 free(p);
814}
815void ssh2_pkt_send(void) {
816 int cipherblk, maclen, padding, i;
817 static unsigned long outgoing_sequence = 0;
818
819 /*
820 * Add padding. At least four bytes, and must also bring total
821 * length (minus MAC) up to a multiple of the block size.
822 */
823 cipherblk = cipher ? cipher->blksize : 8; /* block size */
824 cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */
825 padding = 4;
826 padding += (cipherblk - (pktout.length + padding) % cipherblk) % cipherblk;
827 pktout.data[4] = padding;
828 for (i = 0; i < padding; i++)
829 pktout.data[pktout.length + i] = random_byte();
830 PUT_32BIT(pktout.data, pktout.length + padding - 4);
831 if (csmac)
832 csmac->generate(pktout.data, pktout.length + padding,
833 outgoing_sequence);
834 outgoing_sequence++; /* whether or not we MACed */
835
836#if 0
837 debug(("Sending packet len=%d\r\n", pktout.length+padding));
838 for (i = 0; i < pktout.length+padding; i++)
839 debug((" %02x", (unsigned char)pktout.data[i]));
840 debug(("\r\n"));
841#endif
842
843 if (cscipher)
844 cscipher->encrypt(pktout.data, pktout.length + padding);
845 maclen = csmac ? csmac->len : 0;
846
847 s_write(pktout.data, pktout.length + padding + maclen);
848}
849
850#if 0
851void bndebug(char *string, Bignum b) {
852 unsigned char *p;
853 int i, len;
854 p = ssh2_mpint_fmt(b, &len);
855 debug(("%s", string));
856 for (i = 0; i < len; i++)
857 debug((" %02x", p[i]));
858 debug(("\r\n"));
859 free(p);
860}
861#endif
862
863void sha_mpint(SHA_State *s, Bignum b) {
864 unsigned char *p;
865 int len;
866 p = ssh2_mpint_fmt(b, &len);
867 sha_string(s, p, len);
868 free(p);
869}
870
871/*
872 * SSH2 packet decode functions.
873 */
874unsigned long ssh2_pkt_getuint32(void) {
875 unsigned long value;
876 if (pktin.length - pktin.savedpos < 4)
877 return 0; /* arrgh, no way to decline (FIXME?) */
878 value = GET_32BIT(pktin.data+pktin.savedpos);
879 pktin.savedpos += 4;
880 return value;
881}
882void ssh2_pkt_getstring(char **p, int *length) {
883 *p = NULL;
884 if (pktin.length - pktin.savedpos < 4)
885 return;
886 *length = GET_32BIT(pktin.data+pktin.savedpos);
887 pktin.savedpos += 4;
888 if (pktin.length - pktin.savedpos < *length)
889 return;
890 *p = pktin.data+pktin.savedpos;
891 pktin.savedpos += *length;
892}
893Bignum ssh2_pkt_getmp(void) {
894 char *p;
895 int i, j, length;
896 Bignum b;
897
898 ssh2_pkt_getstring(&p, &length);
899 if (!p)
900 return NULL;
901 if (p[0] & 0x80)
902 fatalbox("internal error: Can't handle negative mpints");
903 b = newbn((length+1)/2);
904 for (i = 0; i < length; i++) {
905 j = length - 1 - i;
906 if (j & 1)
907 b[j/2+1] |= ((unsigned char)p[i]) << 8;
908 else
909 b[j/2+1] |= ((unsigned char)p[i]);
910 }
911 return b;
912}
913
374330e2 914static int do_ssh_init(void) {
c5e9c988 915 char c, *vsp;
374330e2 916 char version[10];
c5e9c988 917 char vstring[80];
918 char vlog[sizeof(vstring)+20];
374330e2 919 int i;
920
921#ifdef FWHACK
922 i = 0;
923 while (s_read(&c, 1) == 1) {
924 if (c == 'S' && i < 2) i++;
925 else if (c == 'S' && i == 2) i = 2;
926 else if (c == 'H' && i == 2) break;
927 else i = 0;
928 }
929#else
930 if (s_read(&c,1) != 1 || c != 'S') return 0;
931 if (s_read(&c,1) != 1 || c != 'S') return 0;
932 if (s_read(&c,1) != 1 || c != 'H') return 0;
933#endif
c5e9c988 934 strcpy(vstring, "SSH-");
935 vsp = vstring+4;
374330e2 936 if (s_read(&c,1) != 1 || c != '-') return 0;
937 i = 0;
938 while (1) {
939 if (s_read(&c,1) != 1)
940 return 0;
c5e9c988 941 if (vsp < vstring+sizeof(vstring)-1)
942 *vsp++ = c;
374330e2 943 if (i >= 0) {
944 if (c == '-') {
945 version[i] = '\0';
946 i = -1;
947 } else if (i < sizeof(version)-1)
948 version[i++] = c;
949 }
950 else if (c == '\n')
951 break;
952 }
953
c5e9c988 954 *vsp = 0;
955 sprintf(vlog, "Server version: %s", vstring);
956 vlog[strcspn(vlog, "\r\n")] = '\0';
957 logevent(vlog);
958
7cca0d81 959 if (ssh_versioncmp(version, "2.0" /* FIXME: "1.99" */ ) >= 0) {
e5574168 960 /*
961 * This is a v2 server. Begin v2 protocol.
962 */
963 char *verstring = "SSH-2.0-PuTTY";
964 SHA_Init(&exhash);
965 /*
966 * Hash our version string and their version string.
967 */
968 sha_string(&exhash, verstring, strlen(verstring));
969 sha_string(&exhash, vstring, strcspn(vstring, "\r\n"));
970 sprintf(vstring, "%s\n", verstring);
971 sprintf(vlog, "We claim version: %s", verstring);
972 logevent(vlog);
973 logevent("Using SSH protocol version 2");
974 s_write(vstring, strlen(vstring));
975 ssh_protocol = ssh2_protocol;
6abbf9e3 976 ssh_version = 2;
e5574168 977 s_rdpkt = ssh2_rdpkt;
978 } else {
979 /*
980 * This is a v1 server. Begin v1 protocol.
981 */
982 sprintf(vstring, "SSH-%s-PuTTY\n",
983 (ssh_versioncmp(version, "1.5") <= 0 ? version : "1.5"));
984 sprintf(vlog, "We claim version: %s", vstring);
985 vlog[strcspn(vlog, "\r\n")] = '\0';
986 logevent(vlog);
987 logevent("Using SSH protocol version 1");
988 s_write(vstring, strlen(vstring));
989 ssh_protocol = ssh1_protocol;
6abbf9e3 990 ssh_version = 1;
e5574168 991 s_rdpkt = ssh1_rdpkt;
992 }
fef97f43 993 return 1;
374330e2 994}
995
fb09bf1c 996/*
997 * Handle the key exchange and user authentication phases.
998 */
e5574168 999static int do_ssh1_login(unsigned char *in, int inlen, int ispkt)
fb09bf1c 1000{
374330e2 1001 int i, j, len;
374330e2 1002 unsigned char *rsabuf, *keystr1, *keystr2;
1003 unsigned char cookie[8];
1004 struct RSAKey servkey, hostkey;
1005 struct MD5Context md5c;
ccbfb941 1006 static unsigned long supported_ciphers_mask, supported_auths_mask;
7cca0d81 1007 static int tried_publickey;
1008 static unsigned char session_id[16];
bea1ef5f 1009 int cipher_type;
374330e2 1010
374330e2 1011 crBegin;
1012
fb09bf1c 1013 if (!ispkt) crWaitUntil(ispkt);
374330e2 1014
e5574168 1015 if (pktin.type != SSH1_SMSG_PUBLIC_KEY)
374330e2 1016 fatalbox("Public key packet not received");
1017
c5e9c988 1018 logevent("Received public keys");
374330e2 1019
c5e9c988 1020 memcpy(cookie, pktin.body, 8);
374330e2 1021
7cca0d81 1022 i = makekey(pktin.body+8, &servkey, &keystr1, 0);
1023 j = makekey(pktin.body+8+i, &hostkey, &keystr2, 0);
374330e2 1024
c5e9c988 1025 /*
1026 * Hash the host key and print the hash in the log box. Just as
1027 * a last resort in case the registry's host key checking is
1028 * compromised, we'll allow the user some ability to verify
1029 * host keys by eye.
1030 */
1031 MD5Init(&md5c);
1032 MD5Update(&md5c, keystr2, hostkey.bytes);
1033 MD5Final(session_id, &md5c);
1034 {
1035 char logmsg[80];
1036 int i;
1037 logevent("Host key MD5 is:");
1038 strcpy(logmsg, " ");
1039 for (i = 0; i < 16; i++)
1040 sprintf(logmsg+strlen(logmsg), "%02x", session_id[i]);
1041 logevent(logmsg);
1042 }
1043
fb09bf1c 1044 supported_ciphers_mask = GET_32BIT(pktin.body+12+i+j);
1045 supported_auths_mask = GET_32BIT(pktin.body+16+i+j);
bea1ef5f 1046
c5e9c988 1047 MD5Init(&md5c);
374330e2 1048 MD5Update(&md5c, keystr2, hostkey.bytes);
1049 MD5Update(&md5c, keystr1, servkey.bytes);
1050 MD5Update(&md5c, pktin.body, 8);
374330e2 1051 MD5Final(session_id, &md5c);
1052
1053 for (i=0; i<32; i++)
1054 session_key[i] = random_byte();
1055
1056 len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes);
1057
1058 rsabuf = malloc(len);
1059 if (!rsabuf)
1060 fatalbox("Out of memory");
1061
89ee5268 1062 /*
1063 * Verify the host key.
1064 */
1065 {
1066 /*
1067 * First format the key into a string.
1068 */
1069 int len = rsastr_len(&hostkey);
1070 char *keystr = malloc(len);
1071 if (!keystr)
1072 fatalbox("Out of memory");
1073 rsastr_fmt(keystr, &hostkey);
1074 verify_ssh_host_key(savedhost, keystr);
1075 free(keystr);
1076 }
374330e2 1077
1078 for (i=0; i<32; i++) {
1079 rsabuf[i] = session_key[i];
1080 if (i < 16)
1081 rsabuf[i] ^= session_id[i];
1082 }
1083
1084 if (hostkey.bytes > servkey.bytes) {
1085 rsaencrypt(rsabuf, 32, &servkey);
1086 rsaencrypt(rsabuf, servkey.bytes, &hostkey);
1087 } else {
1088 rsaencrypt(rsabuf, 32, &hostkey);
1089 rsaencrypt(rsabuf, hostkey.bytes, &servkey);
1090 }
1091
c5e9c988 1092 logevent("Encrypted session key");
1093
bea1ef5f 1094 cipher_type = cfg.cipher == CIPHER_BLOWFISH ? SSH_CIPHER_BLOWFISH :
9697bfd2 1095 cfg.cipher == CIPHER_DES ? SSH_CIPHER_DES :
bea1ef5f 1096 SSH_CIPHER_3DES;
1097 if ((supported_ciphers_mask & (1 << cipher_type)) == 0) {
1098 c_write("Selected cipher not supported, falling back to 3DES\r\n", 53);
1099 cipher_type = SSH_CIPHER_3DES;
1100 }
c5e9c988 1101 switch (cipher_type) {
1102 case SSH_CIPHER_3DES: logevent("Using 3DES encryption"); break;
1103 case SSH_CIPHER_DES: logevent("Using single-DES encryption"); break;
1104 case SSH_CIPHER_BLOWFISH: logevent("Using Blowfish encryption"); break;
1105 }
bea1ef5f 1106
e5574168 1107 send_packet(SSH1_CMSG_SESSION_KEY,
fb09bf1c 1108 PKT_CHAR, cipher_type,
1109 PKT_DATA, cookie, 8,
1110 PKT_CHAR, (len*8) >> 8, PKT_CHAR, (len*8) & 0xFF,
1111 PKT_DATA, rsabuf, len,
1112 PKT_INT, 0,
1113 PKT_END);
1114
c5e9c988 1115 logevent("Trying to enable encryption...");
374330e2 1116
1117 free(rsabuf);
1118
bea1ef5f 1119 cipher = cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish :
9697bfd2 1120 cipher_type == SSH_CIPHER_DES ? &ssh_des :
bea1ef5f 1121 &ssh_3des;
374330e2 1122 cipher->sesskey(session_key);
1123
fb09bf1c 1124 crWaitUntil(ispkt);
374330e2 1125
e5574168 1126 if (pktin.type != SSH1_SMSG_SUCCESS)
374330e2 1127 fatalbox("Encryption not successfully enabled");
1128
c5e9c988 1129 logevent("Successfully started encryption");
1130
374330e2 1131 fflush(stdout);
1132 {
1133 static char username[100];
1134 static int pos = 0;
1135 static char c;
4017be6d 1136 if (!(flags & FLAG_CONNECTION) && !*cfg.username) {
374330e2 1137 c_write("login as: ", 10);
1138 while (pos >= 0) {
fb09bf1c 1139 crWaitUntil(!ispkt);
374330e2 1140 while (inlen--) switch (c = *in++) {
1141 case 10: case 13:
1142 username[pos] = 0;
1143 pos = -1;
1144 break;
1145 case 8: case 127:
1146 if (pos > 0) {
1147 c_write("\b \b", 3);
1148 pos--;
1149 }
1150 break;
1151 case 21: case 27:
1152 while (pos > 0) {
1153 c_write("\b \b", 3);
1154 pos--;
1155 }
1156 break;
1157 case 3: case 4:
1158 random_save_seed();
1159 exit(0);
1160 break;
1161 default:
40d24aa6 1162 if (((c >= ' ' && c <= '~') ||
1163 ((unsigned char)c >= 160)) && pos < 40) {
374330e2 1164 username[pos++] = c;
1165 c_write(&c, 1);
1166 }
1167 break;
1168 }
1169 }
1170 c_write("\r\n", 2);
1171 username[strcspn(username, "\n\r")] = '\0';
1172 } else {
1173 char stuff[200];
1174 strncpy(username, cfg.username, 99);
1175 username[99] = '\0';
4017be6d 1176 if (flags & FLAG_VERBOSE) {
fb09bf1c 1177 sprintf(stuff, "Sent username \"%s\".\r\n", username);
4017be6d 1178 c_write(stuff, strlen(stuff));
fb09bf1c 1179 }
374330e2 1180 }
fb09bf1c 1181
e5574168 1182 send_packet(SSH1_CMSG_USER, PKT_STR, username, PKT_END);
c5e9c988 1183 {
1184 char userlog[20+sizeof(username)];
1185 sprintf(userlog, "Sent username \"%s\"", username);
1186 logevent(userlog);
1187 }
374330e2 1188 }
1189
fb09bf1c 1190 crWaitUntil(ispkt);
374330e2 1191
7cca0d81 1192 tried_publickey = 0;
1193
e5574168 1194 while (pktin.type == SSH1_SMSG_FAILURE) {
374330e2 1195 static char password[100];
1196 static int pos;
1197 static char c;
ccbfb941 1198 static int pwpkt_type;
ccbfb941 1199 /*
1200 * Show password prompt, having first obtained it via a TIS
1201 * exchange if we're doing TIS authentication.
1202 */
e5574168 1203 pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
7cca0d81 1204 if (*cfg.keyfile && !tried_publickey)
1205 pwpkt_type = SSH1_CMSG_AUTH_RSA;
fb09bf1c 1206
4017be6d 1207 if (pwpkt_type == SSH1_CMSG_AUTH_PASSWORD && !FLAG_WINDOWED) {
fb09bf1c 1208 char prompt[200];
1209 sprintf(prompt, "%s@%s's password: ", cfg.username, savedhost);
85ee8208 1210 if (!ssh_get_password(prompt, password, sizeof(password))) {
1211 /*
1212 * get_password failed to get a password (for
1213 * example because one was supplied on the command
1214 * line which has already failed to work).
1215 * Terminate.
1216 */
1217 logevent("No more passwords to try");
1218 ssh_state = SSH_STATE_CLOSED;
1219 crReturn(1);
1220 }
fb09bf1c 1221 } else {
1222
7cca0d81 1223 if (pktin.type == SSH1_SMSG_FAILURE &&
1224 cfg.try_tis_auth &&
1225 (supported_auths_mask & (1<<SSH1_AUTH_TIS))) {
1226 pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
1227 logevent("Requested TIS authentication");
1228 send_packet(SSH1_CMSG_AUTH_TIS, PKT_END);
1229 crWaitUntil(ispkt);
1230 if (pktin.type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
1231 logevent("TIS authentication declined");
1232 c_write("TIS authentication refused.\r\n", 29);
1233 } else {
1234 int challengelen = ((pktin.body[0] << 24) |
1235 (pktin.body[1] << 16) |
1236 (pktin.body[2] << 8) |
1237 (pktin.body[3]));
1238 logevent("Received TIS challenge");
1239 c_write(pktin.body+4, challengelen);
1240 }
1241 }
1242 if (pwpkt_type == SSH1_CMSG_AUTH_PASSWORD)
1243 c_write("password: ", 10);
1244 if (pwpkt_type == SSH1_CMSG_AUTH_RSA) {
4017be6d 1245 if (flags & FLAG_VERBOSE)
1246 c_write("Trying public key authentication.\r\n", 35);
7cca0d81 1247 if (!rsakey_encrypted(cfg.keyfile)) {
4017be6d 1248 if (flags & FLAG_VERBOSE)
1249 c_write("No passphrase required.\r\n", 25);
7cca0d81 1250 goto tryauth;
1251 }
1252 c_write("passphrase: ", 12);
ccbfb941 1253 }
ccbfb941 1254
7cca0d81 1255 pos = 0;
1256 while (pos >= 0) {
1257 crWaitUntil(!ispkt);
1258 while (inlen--) switch (c = *in++) {
1259 case 10: case 13:
1260 password[pos] = 0;
1261 pos = -1;
1262 break;
1263 case 8: case 127:
1264 if (pos > 0)
1265 pos--;
1266 break;
1267 case 21: case 27:
1268 pos = 0;
1269 break;
1270 case 3: case 4:
1271 random_save_seed();
1272 exit(0);
1273 break;
1274 default:
1275 if (((c >= ' ' && c <= '~') ||
1276 ((unsigned char)c >= 160)) && pos < sizeof(password))
1277 password[pos++] = c;
1278 break;
1279 }
1280 }
1281 c_write("\r\n", 2);
fb09bf1c 1282
1283 }
1284
7cca0d81 1285 tryauth:
1286 if (pwpkt_type == SSH1_CMSG_AUTH_RSA) {
1287 /*
1288 * Try public key authentication with the specified
1289 * key file.
1290 */
1291 static struct RSAKey pubkey;
1292 static Bignum challenge, response;
1293 static int i;
1294 static unsigned char buffer[32];
1295
1296 tried_publickey = 1;
1297 i = loadrsakey(cfg.keyfile, &pubkey, password);
1298 if (i == 0) {
1299 c_write("Couldn't load public key from ", 30);
1300 c_write(cfg.keyfile, strlen(cfg.keyfile));
1301 c_write(".\r\n", 3);
1302 continue; /* go and try password */
1303 }
1304 if (i == -1) {
1305 c_write("Wrong passphrase.\r\n", 19);
1306 tried_publickey = 0;
1307 continue; /* try again */
1308 }
1309
1310 /*
1311 * Send a public key attempt.
1312 */
1313 send_packet(SSH1_CMSG_AUTH_RSA,
1314 PKT_BIGNUM, pubkey.modulus, PKT_END);
1315
1316 crWaitUntil(ispkt);
1317 if (pktin.type == SSH1_SMSG_FAILURE) {
4017be6d 1318 if (flags & FLAG_VERBOSE)
1319 c_write("Server refused our public key.\r\n", 32);
7cca0d81 1320 continue; /* go and try password */
1321 }
1322 if (pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE)
1323 fatalbox("Bizarre response to offer of public key");
1324 ssh1_read_bignum(pktin.body, &challenge);
1325 response = rsadecrypt(challenge, &pubkey);
1326 freebn(pubkey.private_exponent); /* burn the evidence */
1327
1328 for (i = 0; i < 32; i += 2) {
1329 buffer[i] = response[16-i/2] >> 8;
1330 buffer[i+1] = response[16-i/2] & 0xFF;
1331 }
1332
1333 MD5Init(&md5c);
1334 MD5Update(&md5c, buffer, 32);
1335 MD5Update(&md5c, session_id, 16);
1336 MD5Final(buffer, &md5c);
1337
1338 send_packet(SSH1_CMSG_AUTH_RSA_RESPONSE,
1339 PKT_DATA, buffer, 16, PKT_END);
1340
1341 crWaitUntil(ispkt);
1342 if (pktin.type == SSH1_SMSG_FAILURE) {
4017be6d 1343 if (flags & FLAG_VERBOSE)
1344 c_write("Failed to authenticate with our public key.\r\n",
1345 45);
7cca0d81 1346 continue; /* go and try password */
1347 } else if (pktin.type != SSH1_SMSG_SUCCESS) {
1348 fatalbox("Bizarre response to RSA authentication response");
1349 }
1350
1351 break; /* we're through! */
1352 } else {
1353 send_packet(pwpkt_type, PKT_STR, password, PKT_END);
1354 }
c5e9c988 1355 logevent("Sent password");
374330e2 1356 memset(password, 0, strlen(password));
fb09bf1c 1357 crWaitUntil(ispkt);
e5574168 1358 if (pktin.type == SSH1_SMSG_FAILURE) {
4017be6d 1359 if (flags & FLAG_VERBOSE)
1360 c_write("Access denied\r\n", 15);
c5e9c988 1361 logevent("Authentication refused");
e5574168 1362 } else if (pktin.type == SSH1_MSG_DISCONNECT) {
fb09bf1c 1363 logevent("Received disconnect request");
85ee8208 1364 ssh_state = SSH_STATE_CLOSED;
1365 crReturn(1);
e5574168 1366 } else if (pktin.type != SSH1_SMSG_SUCCESS) {
374330e2 1367 fatalbox("Strange packet received, type %d", pktin.type);
1368 }
1369 }
1370
c5e9c988 1371 logevent("Authentication successful");
1372
fb09bf1c 1373 crFinish(1);
1374}
1375
e5574168 1376static void ssh1_protocol(unsigned char *in, int inlen, int ispkt) {
fb09bf1c 1377 crBegin;
1378
1379 random_init();
1380
e5574168 1381 while (!do_ssh1_login(in, inlen, ispkt)) {
fb09bf1c 1382 crReturnV;
85ee8208 1383 }
1384 if (ssh_state == SSH_STATE_CLOSED)
1385 crReturnV;
fb09bf1c 1386
fef97f43 1387 if (!cfg.nopty) {
e5574168 1388 send_packet(SSH1_CMSG_REQUEST_PTY,
fb09bf1c 1389 PKT_STR, cfg.termtype,
1390 PKT_INT, rows, PKT_INT, cols,
1391 PKT_INT, 0, PKT_INT, 0,
1392 PKT_CHAR, 0,
1393 PKT_END);
fef97f43 1394 ssh_state = SSH_STATE_INTERMED;
1395 do { crReturnV; } while (!ispkt);
e5574168 1396 if (pktin.type != SSH1_SMSG_SUCCESS && pktin.type != SSH1_SMSG_FAILURE) {
fef97f43 1397 fatalbox("Protocol confusion");
e5574168 1398 } else if (pktin.type == SSH1_SMSG_FAILURE) {
fef97f43 1399 c_write("Server refused to allocate pty\r\n", 32);
1400 }
c5e9c988 1401 logevent("Allocated pty");
374330e2 1402 }
1403
6abbf9e3 1404 if (*cfg.remote_cmd)
1405 send_packet(SSH1_CMSG_EXEC_CMD, PKT_STR, cfg.remote_cmd, PKT_END);
1406 else
1407 send_packet(SSH1_CMSG_EXEC_SHELL, PKT_END);
c5e9c988 1408 logevent("Started session");
374330e2 1409
1410 ssh_state = SSH_STATE_SESSION;
1411 if (size_needed)
1412 ssh_size();
1413
1414 while (1) {
1415 crReturnV;
1416 if (ispkt) {
e5574168 1417 if (pktin.type == SSH1_SMSG_STDOUT_DATA ||
1418 pktin.type == SSH1_SMSG_STDERR_DATA) {
fb09bf1c 1419 long len = GET_32BIT(pktin.body);
1420 c_write(pktin.body+4, len);
e5574168 1421 } else if (pktin.type == SSH1_MSG_DISCONNECT) {
21248260 1422 ssh_state = SSH_STATE_CLOSED;
c5e9c988 1423 logevent("Received disconnect request");
e5574168 1424 } else if (pktin.type == SSH1_SMSG_SUCCESS) {
972a41c8 1425 /* may be from EXEC_SHELL on some servers */
e5574168 1426 } else if (pktin.type == SSH1_SMSG_FAILURE) {
972a41c8 1427 /* may be from EXEC_SHELL on some servers
374330e2 1428 * if no pty is available or in other odd cases. Ignore */
e5574168 1429 } else if (pktin.type == SSH1_SMSG_EXIT_STATUS) {
1430 send_packet(SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
374330e2 1431 } else {
1432 fatalbox("Strange packet received: type %d", pktin.type);
1433 }
1434 } else {
e5574168 1435 send_packet(SSH1_CMSG_STDIN_DATA,
fb09bf1c 1436 PKT_INT, inlen, PKT_DATA, in, inlen, PKT_END);
374330e2 1437 }
1438 }
1439
1440 crFinishV;
1441}
1442
1443/*
e5574168 1444 * Utility routine for decoding comma-separated strings in KEXINIT.
1445 */
1446int in_commasep_string(char *needle, char *haystack, int haylen) {
1447 int needlen = strlen(needle);
1448 while (1) {
1449 /*
1450 * Is it at the start of the string?
1451 */
1452 if (haylen >= needlen && /* haystack is long enough */
1453 !memcmp(needle, haystack, needlen) && /* initial match */
1454 (haylen == needlen || haystack[needlen] == ',')
1455 /* either , or EOS follows */
1456 )
1457 return 1;
1458 /*
1459 * If not, search for the next comma and resume after that.
1460 * If no comma found, terminate.
1461 */
1462 while (haylen > 0 && *haystack != ',')
1463 haylen--, haystack++;
1464 if (haylen == 0)
1465 return 0;
1466 haylen--, haystack++; /* skip over comma itself */
1467 }
1468}
1469
1470/*
d39f364a 1471 * SSH2 key creation method.
1472 */
1473void ssh2_mkkey(Bignum K, char *H, char chr, char *keyspace) {
1474 SHA_State s;
1475 /* First 20 bytes. */
1476 SHA_Init(&s);
1477 sha_mpint(&s, K);
1478 SHA_Bytes(&s, H, 20);
1479 SHA_Bytes(&s, &chr, 1);
1480 SHA_Bytes(&s, H, 20);
1481 SHA_Final(&s, keyspace);
1482 /* Next 20 bytes. */
1483 SHA_Init(&s);
1484 sha_mpint(&s, K);
1485 SHA_Bytes(&s, H, 20);
1486 SHA_Bytes(&s, keyspace, 20);
1487 SHA_Final(&s, keyspace+20);
1488}
1489
1490/*
7cca0d81 1491 * Handle the SSH2 transport layer.
e5574168 1492 */
7cca0d81 1493static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt)
e5574168 1494{
1495 static int i, len;
1496 static char *str;
1497 static Bignum e, f, K;
1498 static struct ssh_cipher *cscipher_tobe = NULL;
1499 static struct ssh_cipher *sccipher_tobe = NULL;
1500 static struct ssh_mac *csmac_tobe = NULL;
1501 static struct ssh_mac *scmac_tobe = NULL;
1502 static struct ssh_compress *cscomp_tobe = NULL;
1503 static struct ssh_compress *sccomp_tobe = NULL;
7cca0d81 1504 static char *hostkeydata, *sigdata, *keystr;
e5574168 1505 static int hostkeylen, siglen;
1506 static unsigned char exchange_hash[20];
d39f364a 1507 static unsigned char keyspace[40];
e5574168 1508
1509 crBegin;
7cca0d81 1510 random_init();
e5574168 1511
7cca0d81 1512 begin_key_exchange:
e5574168 1513 /*
1514 * Construct and send our key exchange packet.
1515 */
1516 ssh2_pkt_init(SSH2_MSG_KEXINIT);
1517 for (i = 0; i < 16; i++)
1518 ssh2_pkt_addbyte((unsigned char)random_byte());
1519 /* List key exchange algorithms. */
1520 ssh2_pkt_addstring_start();
1521 for (i = 0; i < lenof(kex_algs); i++) {
1522 ssh2_pkt_addstring_str(kex_algs[i]->name);
1523 if (i < lenof(kex_algs)-1)
1524 ssh2_pkt_addstring_str(",");
1525 }
1526 /* List server host key algorithms. */
1527 ssh2_pkt_addstring_start();
1528 for (i = 0; i < lenof(hostkey_algs); i++) {
1529 ssh2_pkt_addstring_str(hostkey_algs[i]->name);
1530 if (i < lenof(hostkey_algs)-1)
1531 ssh2_pkt_addstring_str(",");
1532 }
1533 /* List client->server encryption algorithms. */
1534 ssh2_pkt_addstring_start();
1535 for (i = 0; i < lenof(ciphers); i++) {
1536 ssh2_pkt_addstring_str(ciphers[i]->name);
1537 if (i < lenof(ciphers)-1)
1538 ssh2_pkt_addstring_str(",");
1539 }
1540 /* List server->client encryption algorithms. */
1541 ssh2_pkt_addstring_start();
1542 for (i = 0; i < lenof(ciphers); i++) {
1543 ssh2_pkt_addstring_str(ciphers[i]->name);
1544 if (i < lenof(ciphers)-1)
1545 ssh2_pkt_addstring_str(",");
1546 }
1547 /* List client->server MAC algorithms. */
1548 ssh2_pkt_addstring_start();
1549 for (i = 0; i < lenof(macs); i++) {
1550 ssh2_pkt_addstring_str(macs[i]->name);
1551 if (i < lenof(macs)-1)
1552 ssh2_pkt_addstring_str(",");
1553 }
1554 /* List server->client MAC algorithms. */
1555 ssh2_pkt_addstring_start();
1556 for (i = 0; i < lenof(macs); i++) {
1557 ssh2_pkt_addstring_str(macs[i]->name);
1558 if (i < lenof(macs)-1)
1559 ssh2_pkt_addstring_str(",");
1560 }
1561 /* List client->server compression algorithms. */
1562 ssh2_pkt_addstring_start();
1563 for (i = 0; i < lenof(compressions); i++) {
1564 ssh2_pkt_addstring_str(compressions[i]->name);
1565 if (i < lenof(compressions)-1)
1566 ssh2_pkt_addstring_str(",");
1567 }
1568 /* List server->client compression algorithms. */
1569 ssh2_pkt_addstring_start();
1570 for (i = 0; i < lenof(compressions); i++) {
1571 ssh2_pkt_addstring_str(compressions[i]->name);
1572 if (i < lenof(compressions)-1)
1573 ssh2_pkt_addstring_str(",");
1574 }
1575 /* List client->server languages. Empty list. */
1576 ssh2_pkt_addstring_start();
1577 /* List server->client languages. Empty list. */
1578 ssh2_pkt_addstring_start();
1579 /* First KEX packet does _not_ follow, because we're not that brave. */
1580 ssh2_pkt_addbool(FALSE);
1581 /* Reserved. */
1582 ssh2_pkt_adduint32(0);
1583 sha_string(&exhash, pktout.data+5, pktout.length-5);
1584 ssh2_pkt_send();
1585
1586 if (!ispkt) crWaitUntil(ispkt);
1587 sha_string(&exhash, pktin.data+5, pktin.length-5);
1588
1589 /*
1590 * Now examine the other side's KEXINIT to see what we're up
1591 * to.
1592 */
7cca0d81 1593 if (pktin.type != SSH2_MSG_KEXINIT) {
e5574168 1594 fatalbox("expected key exchange packet from server");
7cca0d81 1595 }
e5574168 1596 kex = NULL; hostkey = NULL; cscipher_tobe = NULL; sccipher_tobe = NULL;
1597 csmac_tobe = NULL; scmac_tobe = NULL; cscomp_tobe = NULL; sccomp_tobe = NULL;
1598 pktin.savedpos += 16; /* skip garbage cookie */
1599 ssh2_pkt_getstring(&str, &len); /* key exchange algorithms */
1600 for (i = 0; i < lenof(kex_algs); i++) {
1601 if (in_commasep_string(kex_algs[i]->name, str, len)) {
1602 kex = kex_algs[i];
1603 break;
1604 }
1605 }
1606 ssh2_pkt_getstring(&str, &len); /* host key algorithms */
1607 for (i = 0; i < lenof(hostkey_algs); i++) {
1608 if (in_commasep_string(hostkey_algs[i]->name, str, len)) {
1609 hostkey = hostkey_algs[i];
1610 break;
1611 }
1612 }
1613 ssh2_pkt_getstring(&str, &len); /* client->server cipher */
1614 for (i = 0; i < lenof(ciphers); i++) {
1615 if (in_commasep_string(ciphers[i]->name, str, len)) {
1616 cscipher_tobe = ciphers[i];
1617 break;
1618 }
1619 }
1620 ssh2_pkt_getstring(&str, &len); /* server->client cipher */
1621 for (i = 0; i < lenof(ciphers); i++) {
1622 if (in_commasep_string(ciphers[i]->name, str, len)) {
1623 sccipher_tobe = ciphers[i];
1624 break;
1625 }
1626 }
1627 ssh2_pkt_getstring(&str, &len); /* client->server mac */
1628 for (i = 0; i < lenof(macs); i++) {
1629 if (in_commasep_string(macs[i]->name, str, len)) {
1630 csmac_tobe = macs[i];
1631 break;
1632 }
1633 }
1634 ssh2_pkt_getstring(&str, &len); /* server->client mac */
1635 for (i = 0; i < lenof(macs); i++) {
1636 if (in_commasep_string(macs[i]->name, str, len)) {
1637 scmac_tobe = macs[i];
1638 break;
1639 }
1640 }
1641 ssh2_pkt_getstring(&str, &len); /* client->server compression */
1642 for (i = 0; i < lenof(compressions); i++) {
1643 if (in_commasep_string(compressions[i]->name, str, len)) {
1644 cscomp_tobe = compressions[i];
1645 break;
1646 }
1647 }
1648 ssh2_pkt_getstring(&str, &len); /* server->client compression */
1649 for (i = 0; i < lenof(compressions); i++) {
1650 if (in_commasep_string(compressions[i]->name, str, len)) {
1651 sccomp_tobe = compressions[i];
1652 break;
1653 }
1654 }
e5574168 1655
1656 /*
1657 * Currently we only support Diffie-Hellman and DSS, so let's
1658 * bomb out if those aren't selected.
1659 */
1660 if (kex != &ssh_diffiehellman || hostkey != &ssh_dss)
1661 fatalbox("internal fault: chaos in SSH 2 transport layer");
1662
1663 /*
1664 * Now we begin the fun. Generate and send e for Diffie-Hellman.
1665 */
1666 e = dh_create_e();
e5574168 1667 ssh2_pkt_init(SSH2_MSG_KEXDH_INIT);
1668 ssh2_pkt_addmp(e);
1669 ssh2_pkt_send();
1670
1671 crWaitUntil(ispkt);
7cca0d81 1672 if (pktin.type != SSH2_MSG_KEXDH_REPLY) {
e5574168 1673 fatalbox("expected key exchange packet from server");
7cca0d81 1674 }
e5574168 1675 ssh2_pkt_getstring(&hostkeydata, &hostkeylen);
1676 f = ssh2_pkt_getmp();
e5574168 1677 ssh2_pkt_getstring(&sigdata, &siglen);
1678
1679 K = dh_find_K(f);
e5574168 1680
1681 sha_string(&exhash, hostkeydata, hostkeylen);
1682 sha_mpint(&exhash, e);
1683 sha_mpint(&exhash, f);
1684 sha_mpint(&exhash, K);
1685 SHA_Final(&exhash, exchange_hash);
1686
7cca0d81 1687#if 0
e5574168 1688 debug(("Exchange hash is:\r\n"));
1689 for (i = 0; i < 20; i++)
1690 debug((" %02x", exchange_hash[i]));
1691 debug(("\r\n"));
7cca0d81 1692#endif
1693
1694 hostkey->setkey(hostkeydata, hostkeylen);
1695 if (!hostkey->verifysig(sigdata, siglen, exchange_hash, 20))
1696 fatalbox("Server failed host key check");
e5574168 1697
1698 /*
7cca0d81 1699 * Expect SSH2_MSG_NEWKEYS from server.
d39f364a 1700 */
7cca0d81 1701 crWaitUntil(ispkt);
1702 if (pktin.type != SSH2_MSG_NEWKEYS)
1703 fatalbox("expected new-keys packet from server");
d39f364a 1704
1705 /*
7cca0d81 1706 * Authenticate remote host: verify host key. (We've already
1707 * checked the signature of the exchange hash.)
e5574168 1708 */
7cca0d81 1709 keystr = hostkey->fmtkey();
1710 verify_ssh_host_key(savedhost, keystr);
1711 free(keystr);
d39f364a 1712
1713 /*
7cca0d81 1714 * Send SSH2_MSG_NEWKEYS.
d39f364a 1715 */
1716 ssh2_pkt_init(SSH2_MSG_NEWKEYS);
1717 ssh2_pkt_send();
d39f364a 1718
1719 /*
1720 * Create and initialise session keys.
1721 */
1722 cscipher = cscipher_tobe;
1723 sccipher = sccipher_tobe;
1724 csmac = csmac_tobe;
1725 scmac = scmac_tobe;
1726 cscomp = cscomp_tobe;
1727 sccomp = sccomp_tobe;
1728 /*
1729 * Set IVs after keys.
1730 */
1731 ssh2_mkkey(K, exchange_hash, 'C', keyspace); cscipher->setcskey(keyspace);
1732 ssh2_mkkey(K, exchange_hash, 'D', keyspace); cscipher->setsckey(keyspace);
1733 ssh2_mkkey(K, exchange_hash, 'A', keyspace); cscipher->setcsiv(keyspace);
1734 ssh2_mkkey(K, exchange_hash, 'B', keyspace); sccipher->setsciv(keyspace);
1735 ssh2_mkkey(K, exchange_hash, 'E', keyspace); csmac->setcskey(keyspace);
1736 ssh2_mkkey(K, exchange_hash, 'F', keyspace); scmac->setsckey(keyspace);
1737
033b4cef 1738 /*
7cca0d81 1739 * Now we're encrypting. Begin returning 1 to the protocol main
1740 * function so that other things can run on top of the
1741 * transport. If we ever see a KEXINIT, we must go back to the
1742 * start.
033b4cef 1743 */
7cca0d81 1744 do {
1745 crReturn(1);
1746 } while (!(ispkt && pktin.type == SSH2_MSG_KEXINIT));
1747 goto begin_key_exchange;
e5574168 1748
1749 crFinish(1);
1750}
1751
7cca0d81 1752/*
6abbf9e3 1753 * SSH2: remote identifier for the main session channel.
1754 */
1755static unsigned long ssh_remote_channel;
1756
1757/*
7cca0d81 1758 * Handle the SSH2 userauth and connection layers.
1759 */
1760static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt)
1761{
7cca0d81 1762 static unsigned long remote_winsize;
1763 static unsigned long remote_maxpkt;
1764
e5574168 1765 crBegin;
1766
7cca0d81 1767 /*
1768 * Request userauth protocol, and await a response to it.
1769 */
1770 ssh2_pkt_init(SSH2_MSG_SERVICE_REQUEST);
1771 ssh2_pkt_addstring("ssh-userauth");
1772 ssh2_pkt_send();
1773 crWaitUntilV(ispkt);
1774 if (pktin.type != SSH2_MSG_SERVICE_ACCEPT)
1775 fatalbox("Server refused user authentication protocol");
1776
1777 /*
1778 * FIXME: currently we support only password authentication.
1779 * (This places us technically in violation of the SSH2 spec.
1780 * We must fix this.)
1781 */
1782 while (1) {
1783 /*
1784 * Get a username and a password.
1785 */
1786 static char username[100];
1787 static char password[100];
1788 static int pos = 0;
1789 static char c;
e5574168 1790
4017be6d 1791 if ((flags & FLAG_CONNECTION) && !*cfg.username) {
7cca0d81 1792 c_write("login as: ", 10);
1793 while (pos >= 0) {
1794 crWaitUntilV(!ispkt);
1795 while (inlen--) switch (c = *in++) {
1796 case 10: case 13:
1797 username[pos] = 0;
1798 pos = -1;
1799 break;
1800 case 8: case 127:
1801 if (pos > 0) {
1802 c_write("\b \b", 3);
1803 pos--;
1804 }
1805 break;
1806 case 21: case 27:
1807 while (pos > 0) {
1808 c_write("\b \b", 3);
1809 pos--;
1810 }
1811 break;
1812 case 3: case 4:
1813 random_save_seed();
1814 exit(0);
1815 break;
1816 default:
1817 if (((c >= ' ' && c <= '~') ||
1818 ((unsigned char)c >= 160)) && pos < 40) {
1819 username[pos++] = c;
1820 c_write(&c, 1);
1821 }
1822 break;
1823 }
1824 }
1825 c_write("\r\n", 2);
1826 username[strcspn(username, "\n\r")] = '\0';
1827 } else {
1828 char stuff[200];
1829 strncpy(username, cfg.username, 99);
1830 username[99] = '\0';
4017be6d 1831 if (flags & FLAG_VERBOSE) {
7cca0d81 1832 sprintf(stuff, "Using username \"%s\".\r\n", username);
1833 c_write(stuff, strlen(stuff));
1834 }
1835 }
1836
4017be6d 1837 if (!(flags & FLAG_WINDOWED)) {
7cca0d81 1838 char prompt[200];
1839 sprintf(prompt, "%s@%s's password: ", cfg.username, savedhost);
1840 if (!ssh_get_password(prompt, password, sizeof(password))) {
1841 /*
1842 * get_password failed to get a password (for
1843 * example because one was supplied on the command
1844 * line which has already failed to work).
1845 * Terminate.
1846 */
1847 logevent("No more passwords to try");
1848 ssh_state = SSH_STATE_CLOSED;
1849 crReturnV;
1850 }
1851 } else {
1852 c_write("password: ", 10);
1853
1854 pos = 0;
1855 while (pos >= 0) {
1856 crWaitUntilV(!ispkt);
1857 while (inlen--) switch (c = *in++) {
1858 case 10: case 13:
1859 password[pos] = 0;
1860 pos = -1;
1861 break;
1862 case 8: case 127:
1863 if (pos > 0)
1864 pos--;
1865 break;
1866 case 21: case 27:
1867 pos = 0;
1868 break;
1869 case 3: case 4:
1870 random_save_seed();
1871 exit(0);
1872 break;
1873 default:
1874 if (((c >= ' ' && c <= '~') ||
1875 ((unsigned char)c >= 160)) && pos < 40)
1876 password[pos++] = c;
1877 break;
1878 }
1879 }
1880 c_write("\r\n", 2);
1881 }
1882
1883 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
1884 ssh2_pkt_addstring(username);
1885 ssh2_pkt_addstring("ssh-connection"); /* service requested */
1886 ssh2_pkt_addstring("password");
1887 ssh2_pkt_addbool(FALSE);
1888 ssh2_pkt_addstring(password);
1889 ssh2_pkt_send();
1890
1891 crWaitUntilV(ispkt);
1892 if (pktin.type != SSH2_MSG_USERAUTH_SUCCESS) {
1893 c_write("Access denied\r\n", 15);
1894 logevent("Authentication refused");
1895 } else
1896 break;
1897 }
1898
1899 /*
1900 * Now we're authenticated for the connection protocol. The
1901 * connection protocol will automatically have started at this
1902 * point; there's no need to send SERVICE_REQUEST.
1903 */
1904
1905 /*
1906 * So now create a channel with a session in it.
1907 */
1908 ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN);
1909 ssh2_pkt_addstring("session");
1910 ssh2_pkt_adduint32(100); /* as good as any */
1911 ssh2_pkt_adduint32(0xFFFFFFFFUL); /* very big window which we ignore */
1912 ssh2_pkt_adduint32(0xFFFFFFFFUL); /* very big max pkt size */
1913 ssh2_pkt_send();
1914 crWaitUntilV(ispkt);
1915 if (pktin.type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
1916 fatalbox("Server refused to open a session");
1917 /* FIXME: error data comes back in FAILURE packet */
1918 }
1919 if (ssh2_pkt_getuint32() != 100) {
1920 fatalbox("Server's channel confirmation cited wrong channel");
1921 }
6abbf9e3 1922 ssh_remote_channel = ssh2_pkt_getuint32();
7cca0d81 1923 remote_winsize = ssh2_pkt_getuint32();
1924 remote_maxpkt = ssh2_pkt_getuint32();
1925 logevent("Opened channel for session");
1926
1927 /*
1928 * Now allocate a pty for the session.
1929 */
1930 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
6abbf9e3 1931 ssh2_pkt_adduint32(ssh_remote_channel); /* recipient channel */
7cca0d81 1932 ssh2_pkt_addstring("pty-req");
1933 ssh2_pkt_addbool(1); /* want reply */
1934 ssh2_pkt_addstring(cfg.termtype);
1935 ssh2_pkt_adduint32(cols);
1936 ssh2_pkt_adduint32(rows);
1937 ssh2_pkt_adduint32(0); /* pixel width */
1938 ssh2_pkt_adduint32(0); /* pixel height */
1939 ssh2_pkt_addstring_start();
1940 ssh2_pkt_addstring_data("\0", 1); /* TTY_OP_END, no special options */
1941 ssh2_pkt_send();
1942
1943 do { /* FIXME: pay attention to these */
1944 crWaitUntilV(ispkt);
1945 } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1946
1947 if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
1948 if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
1949 fatalbox("Server got confused by pty request");
1950 }
1951 c_write("Server refused to allocate pty\r\n", 32);
1952 } else {
1953 logevent("Allocated pty");
1954 }
1955
1956 /*
1957 * Start a shell.
1958 */
1959 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
6abbf9e3 1960 ssh2_pkt_adduint32(ssh_remote_channel); /* recipient channel */
7cca0d81 1961 ssh2_pkt_addstring("shell");
1962 ssh2_pkt_addbool(1); /* want reply */
1963 ssh2_pkt_send();
1964 do { /* FIXME: pay attention to these */
1965 crWaitUntilV(ispkt);
1966 } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1967 if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
1968 if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
1969 fatalbox("Server got confused by shell request");
1970 }
1971 fatalbox("Server refused to start a shell");
1972 } else {
1973 logevent("Started a shell");
1974 }
1975
1976 /*
1977 * Transfer data!
1978 */
1979 while (1) {
e5574168 1980 crReturnV;
7cca0d81 1981 if (ispkt) {
1982 if (pktin.type == SSH2_MSG_CHANNEL_DATA ||
1983 pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA) {
1984 char *data;
1985 int length;
1986 if (ssh2_pkt_getuint32() != 100)
1987 continue; /* wrong channel */
1988 if (pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
1989 ssh2_pkt_getuint32() != SSH2_EXTENDED_DATA_STDERR)
1990 continue; /* extended but not stderr */
1991 ssh2_pkt_getstring(&data, &length);
1992 if (data)
1993 c_write(data, length);
1994 } else if (pktin.type == SSH2_MSG_DISCONNECT) {
1995 ssh_state = SSH_STATE_CLOSED;
1996 logevent("Received disconnect request");
1997 } else if (pktin.type == SSH2_MSG_CHANNEL_REQUEST) {
1998 continue; /* exit status et al; ignore (FIXME?) */
1999 } else if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
2000 continue; /* ignore for now (FIXME!) */
2001 } else {
2002 fatalbox("Strange packet received: type %d", pktin.type);
2003 }
2004 } else {
2005 /* FIXME: for now, ignore window size */
2006 ssh2_pkt_init(SSH2_MSG_CHANNEL_DATA);
6abbf9e3 2007 ssh2_pkt_adduint32(ssh_remote_channel);
7cca0d81 2008 ssh2_pkt_addstring_start();
2009 ssh2_pkt_addstring_data(in, inlen);
2010 ssh2_pkt_send();
2011 }
e5574168 2012 }
2013
2014 crFinishV;
2015}
2016
2017/*
7cca0d81 2018 * Handle the top-level SSH2 protocol.
2019 */
2020static void ssh2_protocol(unsigned char *in, int inlen, int ispkt)
2021{
2022 if (do_ssh2_transport(in, inlen, ispkt) == 0)
2023 return;
2024 do_ssh2_authconn(in, inlen, ispkt);
2025}
2026
2027/*
374330e2 2028 * Called to set up the connection. Will arrange for WM_NETEVENT
2029 * messages to be passed to the specified window, whose window
2030 * procedure should then call telnet_msg().
2031 *
2032 * Returns an error message, or NULL on success.
374330e2 2033 */
2034static char *ssh_init (HWND hwnd, char *host, int port, char **realhost) {
fb09bf1c 2035 char *p;
8f203108 2036
2037#ifdef MSCRYPTOAPI
2038 if(crypto_startup() == 0)
2039 return "Microsoft high encryption pack not installed!";
2040#endif
374330e2 2041
fb09bf1c 2042 p = connect_to_host(host, port, realhost);
2043 if (p != NULL)
2044 return p;
374330e2 2045
2046 if (!do_ssh_init())
2047 return "Protocol initialisation error";
2048
4017be6d 2049 if (hwnd && WSAAsyncSelect (s, hwnd, WM_NETEVENT, FD_READ | FD_CLOSE) == SOCKET_ERROR)
374330e2 2050 switch (WSAGetLastError()) {
2051 case WSAENETDOWN: return "Network is down";
2052 default: return "WSAAsyncSelect(): unknown error";
2053 }
2054
2055 return NULL;
2056}
2057
2058/*
2059 * Process a WM_NETEVENT message. Will return 0 if the connection
2060 * has closed, or <0 for a socket error.
2061 */
2062static int ssh_msg (WPARAM wParam, LPARAM lParam) {
2063 int ret;
2064 char buf[256];
2065
8ce72d2c 2066 /*
2067 * Because reading less than the whole of the available pending
2068 * data can generate an FD_READ event, we need to allow for the
2069 * possibility that FD_READ may arrive with FD_CLOSE already in
2070 * the queue; so it's possible that we can get here even with s
2071 * invalid. If so, we return 1 and don't worry about it.
2072 */
2073 if (s == INVALID_SOCKET)
2074 return 1;
374330e2 2075
2076 if (WSAGETSELECTERROR(lParam) != 0)
2077 return -WSAGETSELECTERROR(lParam);
2078
2079 switch (WSAGETSELECTEVENT(lParam)) {
2080 case FD_READ:
8ce72d2c 2081 case FD_CLOSE:
374330e2 2082 ret = recv(s, buf, sizeof(buf), 0);
2083 if (ret < 0 && WSAGetLastError() == WSAEWOULDBLOCK)
2084 return 1;
2085 if (ret < 0) /* any _other_ error */
2086 return -10000-WSAGetLastError();
2087 if (ret == 0) {
2088 s = INVALID_SOCKET;
8ce72d2c 2089 return 0;
374330e2 2090 }
2091 ssh_gotdata (buf, ret);
85ee8208 2092 if (ssh_state == SSH_STATE_CLOSED) {
2093 closesocket(s);
2094 s = INVALID_SOCKET;
2095 return 0;
2096 }
374330e2 2097 return 1;
374330e2 2098 }
2099 return 1; /* shouldn't happen, but WTF */
2100}
2101
2102/*
2103 * Called to send data down the Telnet connection.
2104 */
2105static void ssh_send (char *buf, int len) {
2106 if (s == INVALID_SOCKET)
2107 return;
2108
2109 ssh_protocol(buf, len, 0);
2110}
2111
2112/*
2113 * Called to set the size of the window from Telnet's POV.
2114 */
2115static void ssh_size(void) {
2116 switch (ssh_state) {
2117 case SSH_STATE_BEFORE_SIZE:
21248260 2118 case SSH_STATE_CLOSED:
374330e2 2119 break; /* do nothing */
2120 case SSH_STATE_INTERMED:
2121 size_needed = TRUE; /* buffer for later */
2122 break;
2123 case SSH_STATE_SESSION:
fef97f43 2124 if (!cfg.nopty) {
e5574168 2125 send_packet(SSH1_CMSG_WINDOW_SIZE,
fb09bf1c 2126 PKT_INT, rows, PKT_INT, cols,
2127 PKT_INT, 0, PKT_INT, 0, PKT_END);
fef97f43 2128 }
374330e2 2129 }
2130}
2131
2132/*
6abbf9e3 2133 * Send Telnet special codes. TS_EOF is useful for `plink', so you
2134 * can send an EOF and collect resulting output (e.g. `plink
2135 * hostname sort').
374330e2 2136 */
2137static void ssh_special (Telnet_Special code) {
6abbf9e3 2138 if (code == TS_EOF) {
2139 if (ssh_version = 1) {
2140 send_packet(SSH1_CMSG_EOF, PKT_END);
2141 } else {
2142 ssh2_pkt_init(SSH2_MSG_CHANNEL_EOF);
2143 ssh2_pkt_adduint32(ssh_remote_channel);
2144 ssh2_pkt_send();
2145 }
2146 } else {
2147 /* do nothing */
2148 }
374330e2 2149}
2150
fb09bf1c 2151
2152/*
2153 * Read and decrypt one incoming SSH packet.
2154 * (only used by pSCP)
2155 */
2156static void get_packet(void)
2157{
2158 unsigned char buf[4096], *p;
2159 long to_read;
2160 int len;
2161
fb09bf1c 2162 p = NULL;
2163 len = 0;
2164
2165 while ((to_read = s_rdpkt(&p, &len)) > 0) {
2166 if (to_read > sizeof(buf)) to_read = sizeof(buf);
2167 len = s_read(buf, to_read);
2168 if (len != to_read) {
2169 closesocket(s);
2170 s = INVALID_SOCKET;
2171 return;
2172 }
2173 p = buf;
2174 }
2175
2176 assert(len == 0);
2177}
2178
2179/*
2180 * Receive a block of data over the SSH link. Block until
2181 * all data is available. Return nr of bytes read (0 if lost connection).
2182 * (only used by pSCP)
2183 */
2184int ssh_scp_recv(unsigned char *buf, int len)
2185{
2186 static int pending_input_len = 0;
2187 static unsigned char *pending_input_ptr;
2188 int to_read = len;
2189
fb09bf1c 2190 if (pending_input_len >= to_read) {
2191 memcpy(buf, pending_input_ptr, to_read);
2192 pending_input_ptr += to_read;
2193 pending_input_len -= to_read;
2194 return len;
2195 }
2196
2197 if (pending_input_len > 0) {
2198 memcpy(buf, pending_input_ptr, pending_input_len);
2199 buf += pending_input_len;
2200 to_read -= pending_input_len;
2201 pending_input_len = 0;
2202 }
2203
2204 if (s == INVALID_SOCKET)
2205 return 0;
2206 while (to_read > 0) {
2207 get_packet();
2208 if (s == INVALID_SOCKET)
2209 return 0;
e5574168 2210 if (pktin.type == SSH1_SMSG_STDOUT_DATA) {
fb09bf1c 2211 int plen = GET_32BIT(pktin.body);
2212 if (plen <= to_read) {
2213 memcpy(buf, pktin.body + 4, plen);
2214 buf += plen;
2215 to_read -= plen;
2216 } else {
2217 memcpy(buf, pktin.body + 4, to_read);
2218 pending_input_len = plen - to_read;
2219 pending_input_ptr = pktin.body + 4 + to_read;
2220 to_read = 0;
2221 }
e5574168 2222 } else if (pktin.type == SSH1_SMSG_STDERR_DATA) {
fb09bf1c 2223 int plen = GET_32BIT(pktin.body);
2224 fwrite(pktin.body + 4, plen, 1, stderr);
e5574168 2225 } else if (pktin.type == SSH1_MSG_DISCONNECT) {
fb09bf1c 2226 logevent("Received disconnect request");
e5574168 2227 } else if (pktin.type == SSH1_SMSG_SUCCESS ||
2228 pktin.type == SSH1_SMSG_FAILURE) {
fb09bf1c 2229 /* ignore */
e5574168 2230 } else if (pktin.type == SSH1_SMSG_EXIT_STATUS) {
fb09bf1c 2231 char logbuf[100];
2232 sprintf(logbuf, "Remote exit status: %d", GET_32BIT(pktin.body));
2233 logevent(logbuf);
e5574168 2234 send_packet(SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
fb09bf1c 2235 logevent("Closing connection");
2236 closesocket(s);
2237 s = INVALID_SOCKET;
2238 } else {
2239 fatalbox("Strange packet received: type %d", pktin.type);
2240 }
2241 }
2242
2243 return len;
2244}
2245
2246/*
2247 * Send a block of data over the SSH link.
2248 * Block until all data is sent.
2249 * (only used by pSCP)
2250 */
2251void ssh_scp_send(unsigned char *buf, int len)
2252{
fb09bf1c 2253 if (s == INVALID_SOCKET)
2254 return;
e5574168 2255 send_packet(SSH1_CMSG_STDIN_DATA,
fb09bf1c 2256 PKT_INT, len, PKT_DATA, buf, len, PKT_END);
2257}
2258
2259/*
2260 * Send an EOF notification to the server.
2261 * (only used by pSCP)
2262 */
2263void ssh_scp_send_eof(void)
2264{
fb09bf1c 2265 if (s == INVALID_SOCKET)
2266 return;
e5574168 2267 send_packet(SSH1_CMSG_EOF, PKT_END);
fb09bf1c 2268}
2269
2270/*
2271 * Set up the connection, login on the remote host and
2272 * start execution of a command.
2273 * Returns an error message, or NULL on success.
2274 * (only used by pSCP)
2275 */
2276char *ssh_scp_init(char *host, int port, char *cmd, char **realhost)
2277{
2278 char buf[160], *p;
2279
fb09bf1c 2280#ifdef MSCRYPTOAPI
2281 if (crypto_startup() == 0)
2282 return "Microsoft high encryption pack not installed!";
2283#endif
2284
2285 p = connect_to_host(host, port, realhost);
2286 if (p != NULL)
2287 return p;
2288
2289 random_init();
2290
2291 if (!do_ssh_init())
2292 return "Protocol initialisation error";
2293
2294 /* Exchange keys and login */
2295 do {
2296 get_packet();
2297 if (s == INVALID_SOCKET)
2298 return "Connection closed by remote host";
e5574168 2299 } while (!do_ssh1_login(NULL, 0, 1));
85ee8208 2300
2301 if (ssh_state == SSH_STATE_CLOSED) {
2302 closesocket(s);
2303 s = INVALID_SOCKET;
2304 return "Session initialisation error";
2305 }
fb09bf1c 2306
2307 /* Execute command */
2308 sprintf(buf, "Sending command: %.100s", cmd);
2309 logevent(buf);
e5574168 2310 send_packet(SSH1_CMSG_EXEC_CMD, PKT_STR, cmd, PKT_END);
fb09bf1c 2311
2312 return NULL;
2313}
2314
4017be6d 2315SOCKET ssh_socket(void) { return s; }
fb09bf1c 2316
374330e2 2317Backend ssh_backend = {
2318 ssh_init,
2319 ssh_msg,
2320 ssh_send,
2321 ssh_size,
4017be6d 2322 ssh_special,
2323 ssh_socket
374330e2 2324};
Local modifications for Simon Tatham's `PuTTY' SSH client and terminal emulator