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Stop plink losing data at start of 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;
8ccc75b0 166static int ssh_send_ok;
374330e2 167
168static enum {
169 SSH_STATE_BEFORE_SIZE,
170 SSH_STATE_INTERMED,
21248260 171 SSH_STATE_SESSION,
172 SSH_STATE_CLOSED
374330e2 173} ssh_state = SSH_STATE_BEFORE_SIZE;
174
175static int size_needed = FALSE;
176
177static void s_write (char *buf, int len) {
178 while (len > 0) {
179 int i = send (s, buf, len, 0);
4017be6d 180 noise_ultralight(i);
181 if (i <= 0)
182 fatalbox("Lost connection while sending");
374330e2 183 if (i > 0)
184 len -= i, buf += i;
185 }
186}
187
188static int s_read (char *buf, int len) {
189 int ret = 0;
190 while (len > 0) {
191 int i = recv (s, buf, len, 0);
4017be6d 192 noise_ultralight(i);
374330e2 193 if (i > 0)
194 len -= i, buf += i, ret += i;
195 else
196 return i;
197 }
198 return ret;
199}
200
201static void c_write (char *buf, int len) {
4017be6d 202 if (!(flags & FLAG_CONNECTION)) {
203 int i;
204 for (i = 0; i < len; i++)
205 if (buf[i] != '\r')
206 fputc(buf[i], stderr);
fb09bf1c 207 return;
208 }
c9def1b8 209 while (len--)
210 c_write1(*buf++);
374330e2 211}
212
213struct Packet {
214 long length;
215 int type;
374330e2 216 unsigned char *data;
217 unsigned char *body;
e5574168 218 long savedpos;
374330e2 219 long maxlen;
220};
221
fb09bf1c 222static struct Packet pktin = { 0, 0, NULL, NULL, 0 };
223static struct Packet pktout = { 0, 0, NULL, NULL, 0 };
374330e2 224
6abbf9e3 225static int ssh_version;
e5574168 226static void (*ssh_protocol)(unsigned char *in, int inlen, int ispkt);
227static void ssh1_protocol(unsigned char *in, int inlen, int ispkt);
228static void ssh2_protocol(unsigned char *in, int inlen, int ispkt);
374330e2 229static void ssh_size(void);
230
e5574168 231static int (*s_rdpkt)(unsigned char **data, int *datalen);
fb09bf1c 232
233/*
234 * Collect incoming data in the incoming packet buffer.
e5574168 235 * Decipher and verify the packet when it is completely read.
236 * Drop SSH1_MSG_DEBUG and SSH1_MSG_IGNORE packets.
fb09bf1c 237 * Update the *data and *datalen variables.
238 * Return the additional nr of bytes needed, or 0 when
239 * a complete packet is available.
240 */
e5574168 241static int ssh1_rdpkt(unsigned char **data, int *datalen)
fb09bf1c 242{
243 static long len, pad, biglen, to_read;
572f871e 244 static unsigned long realcrc, gotcrc;
fb09bf1c 245 static unsigned char *p;
246 static int i;
374330e2 247
248 crBegin;
374330e2 249
fb09bf1c 250next_packet:
37508af4 251
fb09bf1c 252 pktin.type = 0;
253 pktin.length = 0;
374330e2 254
fb09bf1c 255 for (i = len = 0; i < 4; i++) {
256 while ((*datalen) == 0)
257 crReturn(4-i);
258 len = (len << 8) + **data;
259 (*data)++, (*datalen)--;
260 }
374330e2 261
fb09bf1c 262#ifdef FWHACK
263 if (len == 0x52656d6f) { /* "Remo"te server has closed ... */
264 len = 0x300; /* big enough to carry to end */
265 }
266#endif
374330e2 267
fb09bf1c 268 pad = 8 - (len % 8);
269 biglen = len + pad;
270 pktin.length = len - 5;
271
272 if (pktin.maxlen < biglen) {
273 pktin.maxlen = biglen;
e5574168 274 pktin.data = (pktin.data == NULL ? malloc(biglen+APIEXTRA) :
275 realloc(pktin.data, biglen+APIEXTRA));
fb09bf1c 276 if (!pktin.data)
277 fatalbox("Out of memory");
278 }
374330e2 279
fb09bf1c 280 to_read = biglen;
281 p = pktin.data;
282 while (to_read > 0) {
283 static int chunk;
284 chunk = to_read;
285 while ((*datalen) == 0)
286 crReturn(to_read);
287 if (chunk > (*datalen))
288 chunk = (*datalen);
289 memcpy(p, *data, chunk);
290 *data += chunk;
291 *datalen -= chunk;
292 p += chunk;
293 to_read -= chunk;
294 }
374330e2 295
fb09bf1c 296 if (cipher)
297 cipher->decrypt(pktin.data, biglen);
374330e2 298
fb09bf1c 299 pktin.type = pktin.data[pad];
300 pktin.body = pktin.data + pad + 1;
374330e2 301
fb09bf1c 302 realcrc = crc32(pktin.data, biglen-4);
303 gotcrc = GET_32BIT(pktin.data+biglen-4);
304 if (gotcrc != realcrc) {
305 fatalbox("Incorrect CRC received on packet");
306 }
572f871e 307
e5574168 308 if (pktin.type == SSH1_SMSG_STDOUT_DATA ||
309 pktin.type == SSH1_SMSG_STDERR_DATA ||
310 pktin.type == SSH1_MSG_DEBUG ||
311 pktin.type == SSH1_SMSG_AUTH_TIS_CHALLENGE) {
fb09bf1c 312 long strlen = GET_32BIT(pktin.body);
313 if (strlen + 4 != pktin.length)
314 fatalbox("Received data packet with bogus string length");
315 }
316
e5574168 317 if (pktin.type == SSH1_MSG_DEBUG) {
fb09bf1c 318 /* log debug message */
319 char buf[80];
320 int strlen = GET_32BIT(pktin.body);
321 strcpy(buf, "Remote: ");
322 if (strlen > 70) strlen = 70;
323 memcpy(buf+8, pktin.body+4, strlen);
324 buf[8+strlen] = '\0';
325 logevent(buf);
326 goto next_packet;
e5574168 327 } else if (pktin.type == SSH1_MSG_IGNORE) {
fb09bf1c 328 /* do nothing */
329 goto next_packet;
330 }
331
332 crFinish(0);
333}
334
e5574168 335static int ssh2_rdpkt(unsigned char **data, int *datalen)
336{
337 static long len, pad, payload, packetlen, maclen;
338 static int i;
339 static int cipherblk;
340 static unsigned long incoming_sequence = 0;
341
342 crBegin;
343
344next_packet:
345
346 pktin.type = 0;
347 pktin.length = 0;
348
349 if (cipher)
350 cipherblk = cipher->blksize;
351 else
352 cipherblk = 8;
353 if (cipherblk < 8)
354 cipherblk = 8;
355
356 if (pktin.maxlen < cipherblk) {
357 pktin.maxlen = cipherblk;
358 pktin.data = (pktin.data == NULL ? malloc(cipherblk+APIEXTRA) :
359 realloc(pktin.data, cipherblk+APIEXTRA));
360 if (!pktin.data)
361 fatalbox("Out of memory");
362 }
363
364 /*
365 * Acquire and decrypt the first block of the packet. This will
366 * contain the length and padding details.
367 */
368 for (i = len = 0; i < cipherblk; i++) {
369 while ((*datalen) == 0)
370 crReturn(cipherblk-i);
371 pktin.data[i] = *(*data)++;
372 (*datalen)--;
373 }
374#ifdef FWHACK
375 if (!memcmp(pktin.data, "Remo", 4)) {/* "Remo"te server has closed ... */
376 /* FIXME */
377 }
378#endif
379 if (sccipher)
380 sccipher->decrypt(pktin.data, cipherblk);
381
382 /*
383 * Now get the length and padding figures.
384 */
385 len = GET_32BIT(pktin.data);
386 pad = pktin.data[4];
387
388 /*
389 * This enables us to deduce the payload length.
390 */
391 payload = len - pad - 1;
392
393 pktin.length = payload + 5;
394
395 /*
396 * So now we can work out the total packet length.
397 */
398 packetlen = len + 4;
399 maclen = scmac ? scmac->len : 0;
400
401 /*
402 * Adjust memory allocation if packet is too big.
403 */
404 if (pktin.maxlen < packetlen) {
405 pktin.maxlen = packetlen;
406 pktin.data = (pktin.data == NULL ? malloc(packetlen+APIEXTRA) :
407 realloc(pktin.data, packetlen+APIEXTRA));
408 if (!pktin.data)
409 fatalbox("Out of memory");
410 }
411
412 /*
413 * Read and decrypt the remainder of the packet.
414 */
415 for (i = cipherblk; i < packetlen + maclen; i++) {
416 while ((*datalen) == 0)
417 crReturn(packetlen + maclen - i);
418 pktin.data[i] = *(*data)++;
419 (*datalen)--;
420 }
421 /* Decrypt everything _except_ the MAC. */
422 if (sccipher)
423 sccipher->decrypt(pktin.data + cipherblk, packetlen - cipherblk);
424
7cca0d81 425#if 0
d39f364a 426 debug(("Got packet len=%d pad=%d\r\n", len, pad));
427 for (i = 0; i < packetlen; i++)
428 debug((" %02x", (unsigned char)pktin.data[i]));
429 debug(("\r\n"));
7cca0d81 430#endif
d39f364a 431
e5574168 432 /*
433 * Check the MAC.
434 */
033b4cef 435 if (scmac && !scmac->verify(pktin.data, len+4, incoming_sequence))
e5574168 436 fatalbox("Incorrect MAC received on packet");
033b4cef 437 incoming_sequence++; /* whether or not we MACed */
e5574168 438
439 pktin.savedpos = 6;
440 pktin.type = pktin.data[5];
e5574168 441
7cca0d81 442 if (pktin.type == SSH2_MSG_IGNORE || pktin.type == SSH2_MSG_DEBUG)
443 goto next_packet; /* FIXME: print DEBUG message */
e5574168 444
445 crFinish(0);
446}
447
fb09bf1c 448static void ssh_gotdata(unsigned char *data, int datalen)
449{
450 while (datalen > 0) {
85ee8208 451 if ( s_rdpkt(&data, &datalen) == 0 ) {
374330e2 452 ssh_protocol(NULL, 0, 1);
85ee8208 453 if (ssh_state == SSH_STATE_CLOSED) {
454 return;
455 }
456 }
374330e2 457 }
374330e2 458}
459
fb09bf1c 460
374330e2 461static void s_wrpkt_start(int type, int len) {
462 int pad, biglen;
463
464 len += 5; /* type and CRC */
465 pad = 8 - (len%8);
466 biglen = len + pad;
467
468 pktout.length = len-5;
469 if (pktout.maxlen < biglen) {
470 pktout.maxlen = biglen;
8f203108 471#ifdef MSCRYPTOAPI
fb09bf1c 472 /* Allocate enough buffer space for extra block
8f203108 473 * for MS CryptEncrypt() */
fb09bf1c 474 pktout.data = (pktout.data == NULL ? malloc(biglen+12) :
475 realloc(pktout.data, biglen+12));
8f203108 476#else
c1f5f956 477 pktout.data = (pktout.data == NULL ? malloc(biglen+4) :
478 realloc(pktout.data, biglen+4));
8f203108 479#endif
374330e2 480 if (!pktout.data)
481 fatalbox("Out of memory");
482 }
483
484 pktout.type = type;
485 pktout.body = pktout.data+4+pad+1;
486}
487
488static void s_wrpkt(void) {
489 int pad, len, biglen, i;
490 unsigned long crc;
491
492 len = pktout.length + 5; /* type and CRC */
493 pad = 8 - (len%8);
494 biglen = len + pad;
495
496 pktout.body[-1] = pktout.type;
497 for (i=0; i<pad; i++)
498 pktout.data[i+4] = random_byte();
499 crc = crc32(pktout.data+4, biglen-4);
fb09bf1c 500 PUT_32BIT(pktout.data+biglen, crc);
501 PUT_32BIT(pktout.data, len);
374330e2 502
503 if (cipher)
504 cipher->encrypt(pktout.data+4, biglen);
505
506 s_write(pktout.data, biglen+4);
507}
508
fb09bf1c 509/*
510 * Construct a packet with the specified contents and
511 * send it to the server.
512 */
513static void send_packet(int pkttype, ...)
514{
515 va_list args;
516 unsigned char *p, *argp, argchar;
517 unsigned long argint;
518 int pktlen, argtype, arglen;
7cca0d81 519 Bignum bn;
520 int i;
fb09bf1c 521
522 pktlen = 0;
523 va_start(args, pkttype);
524 while ((argtype = va_arg(args, int)) != PKT_END) {
525 switch (argtype) {
526 case PKT_INT:
527 (void) va_arg(args, int);
528 pktlen += 4;
529 break;
530 case PKT_CHAR:
531 (void) va_arg(args, char);
532 pktlen++;
533 break;
534 case PKT_DATA:
535 (void) va_arg(args, unsigned char *);
536 arglen = va_arg(args, int);
537 pktlen += arglen;
538 break;
539 case PKT_STR:
540 argp = va_arg(args, unsigned char *);
541 arglen = strlen(argp);
542 pktlen += 4 + arglen;
543 break;
7cca0d81 544 case PKT_BIGNUM:
545 bn = va_arg(args, Bignum);
546 i = 16 * bn[0] - 1;
547 while ( i > 0 && (bn[i/16+1] >> (i%16)) == 0 )
548 i--;
549 pktlen += 2 + (i+7)/8;
550 break;
fb09bf1c 551 default:
552 assert(0);
553 }
554 }
555 va_end(args);
556
557 s_wrpkt_start(pkttype, pktlen);
558 p = pktout.body;
559
560 va_start(args, pkttype);
561 while ((argtype = va_arg(args, int)) != PKT_END) {
562 switch (argtype) {
563 case PKT_INT:
564 argint = va_arg(args, int);
565 PUT_32BIT(p, argint);
566 p += 4;
567 break;
568 case PKT_CHAR:
569 argchar = va_arg(args, unsigned char);
570 *p = argchar;
571 p++;
572 break;
573 case PKT_DATA:
574 argp = va_arg(args, unsigned char *);
575 arglen = va_arg(args, int);
576 memcpy(p, argp, arglen);
577 p += arglen;
578 break;
579 case PKT_STR:
580 argp = va_arg(args, unsigned char *);
581 arglen = strlen(argp);
582 PUT_32BIT(p, arglen);
583 memcpy(p + 4, argp, arglen);
584 p += 4 + arglen;
585 break;
7cca0d81 586 case PKT_BIGNUM:
587 bn = va_arg(args, Bignum);
588 i = 16 * bn[0] - 1;
589 while ( i > 0 && (bn[i/16+1] >> (i%16)) == 0 )
590 i--;
591 *p++ = (i >> 8) & 0xFF;
592 *p++ = i & 0xFF;
593 i = (i + 7) / 8;
594 while (i-- > 0) {
595 if (i % 2)
596 *p++ = bn[i/2+1] >> 8;
597 else
598 *p++ = bn[i/2+1] & 0xFF;
599 }
600 break;
fb09bf1c 601 }
602 }
603 va_end(args);
604
605 s_wrpkt();
606}
607
608
609/*
610 * Connect to specified host and port.
611 * Returns an error message, or NULL on success.
612 * Also places the canonical host name into `realhost'.
613 */
614static char *connect_to_host(char *host, int port, char **realhost)
615{
616 SOCKADDR_IN addr;
617 struct hostent *h;
618 unsigned long a;
619#ifdef FWHACK
620 char *FWhost;
621 int FWport;
622#endif
623
624 savedhost = malloc(1+strlen(host));
625 if (!savedhost)
626 fatalbox("Out of memory");
627 strcpy(savedhost, host);
628
629 if (port < 0)
630 port = 22; /* default ssh port */
631
632#ifdef FWHACK
633 FWhost = host;
634 FWport = port;
635 host = FWSTR;
636 port = 23;
637#endif
638
639 /*
640 * Try to find host.
641 */
642 if ( (a = inet_addr(host)) == (unsigned long) INADDR_NONE) {
643 if ( (h = gethostbyname(host)) == NULL)
644 switch (WSAGetLastError()) {
645 case WSAENETDOWN: return "Network is down";
646 case WSAHOST_NOT_FOUND: case WSANO_DATA:
647 return "Host does not exist";
648 case WSATRY_AGAIN: return "Host not found";
649 default: return "gethostbyname: unknown error";
650 }
651 memcpy (&a, h->h_addr, sizeof(a));
652 *realhost = h->h_name;
653 } else
654 *realhost = host;
655#ifdef FWHACK
656 *realhost = FWhost;
657#endif
658 a = ntohl(a);
659
660 /*
661 * Open socket.
662 */
663 s = socket(AF_INET, SOCK_STREAM, 0);
664 if (s == INVALID_SOCKET)
665 switch (WSAGetLastError()) {
666 case WSAENETDOWN: return "Network is down";
667 case WSAEAFNOSUPPORT: return "TCP/IP support not present";
668 default: return "socket(): unknown error";
669 }
670
671 /*
672 * Bind to local address.
673 */
674 addr.sin_family = AF_INET;
675 addr.sin_addr.s_addr = htonl(INADDR_ANY);
676 addr.sin_port = htons(0);
677 if (bind (s, (struct sockaddr *)&addr, sizeof(addr)) == SOCKET_ERROR)
678 switch (WSAGetLastError()) {
679 case WSAENETDOWN: return "Network is down";
680 default: return "bind(): unknown error";
681 }
682
683 /*
684 * Connect to remote address.
685 */
686 addr.sin_addr.s_addr = htonl(a);
687 addr.sin_port = htons((short)port);
688 if (connect (s, (struct sockaddr *)&addr, sizeof(addr)) == SOCKET_ERROR)
689 switch (WSAGetLastError()) {
690 case WSAENETDOWN: return "Network is down";
691 case WSAECONNREFUSED: return "Connection refused";
692 case WSAENETUNREACH: return "Network is unreachable";
693 case WSAEHOSTUNREACH: return "No route to host";
694 default: return "connect(): unknown error";
695 }
696
697#ifdef FWHACK
698 send(s, "connect ", 8, 0);
699 send(s, FWhost, strlen(FWhost), 0);
700 {
701 char buf[20];
702 sprintf(buf, " %d\n", FWport);
703 send (s, buf, strlen(buf), 0);
704 }
705#endif
706
707 return NULL;
708}
709
9697bfd2 710static int ssh_versioncmp(char *a, char *b) {
711 char *ae, *be;
712 unsigned long av, bv;
713
43aa02a7 714 av = strtoul(a, &ae, 10);
715 bv = strtoul(b, &be, 10);
9697bfd2 716 if (av != bv) return (av < bv ? -1 : +1);
717 if (*ae == '.') ae++;
718 if (*be == '.') be++;
43aa02a7 719 av = strtoul(ae, &ae, 10);
720 bv = strtoul(be, &be, 10);
9697bfd2 721 if (av != bv) return (av < bv ? -1 : +1);
722 return 0;
723}
724
e5574168 725
726/*
727 * Utility routine for putting an SSH-protocol `string' into a SHA
728 * state.
729 */
730#include <stdio.h>
731void sha_string(SHA_State *s, void *str, int len) {
732 unsigned char lenblk[4];
733static FILE *fp;
734 PUT_32BIT(lenblk, len);
735if (!fp) fp = fopen("h:\\statham\\windows\\putty\\data","wb");
736fwrite(lenblk, 4, 1, fp);
737 SHA_Bytes(s, lenblk, 4);
738fwrite(str, len, 1, fp);
739fflush(fp);
740 SHA_Bytes(s, str, len);
741}
742
7cca0d81 743/*
744 * SSH2 packet construction functions.
745 */
746void ssh2_pkt_adddata(void *data, int len) {
747 pktout.length += len;
748 if (pktout.maxlen < pktout.length) {
749 pktout.maxlen = pktout.length + 256;
750 pktout.data = (pktout.data == NULL ? malloc(pktout.maxlen+APIEXTRA) :
751 realloc(pktout.data, pktout.maxlen+APIEXTRA));
752 if (!pktout.data)
753 fatalbox("Out of memory");
754 }
755 memcpy(pktout.data+pktout.length-len, data, len);
756}
757void ssh2_pkt_addbyte(unsigned char byte) {
758 ssh2_pkt_adddata(&byte, 1);
759}
760void ssh2_pkt_init(int pkt_type) {
761 pktout.length = 5;
762 ssh2_pkt_addbyte((unsigned char)pkt_type);
763}
764void ssh2_pkt_addbool(unsigned char value) {
765 ssh2_pkt_adddata(&value, 1);
766}
767void ssh2_pkt_adduint32(unsigned long value) {
768 unsigned char x[4];
769 PUT_32BIT(x, value);
770 ssh2_pkt_adddata(x, 4);
771}
772void ssh2_pkt_addstring_start(void) {
773 ssh2_pkt_adduint32(0);
774 pktout.savedpos = pktout.length;
775}
776void ssh2_pkt_addstring_str(char *data) {
777 ssh2_pkt_adddata(data, strlen(data));
778 PUT_32BIT(pktout.data + pktout.savedpos - 4,
779 pktout.length - pktout.savedpos);
780}
781void ssh2_pkt_addstring_data(char *data, int len) {
782 ssh2_pkt_adddata(data, len);
783 PUT_32BIT(pktout.data + pktout.savedpos - 4,
784 pktout.length - pktout.savedpos);
785}
786void ssh2_pkt_addstring(char *data) {
787 ssh2_pkt_addstring_start();
788 ssh2_pkt_addstring_str(data);
789}
790char *ssh2_mpint_fmt(Bignum b, int *len) {
791 unsigned char *p;
792 int i, n = b[0];
793 p = malloc(n * 2 + 1);
794 if (!p)
795 fatalbox("out of memory");
796 p[0] = 0;
797 for (i = 0; i < n; i++) {
798 p[i*2+1] = (b[n-i] >> 8) & 0xFF;
799 p[i*2+2] = (b[n-i] ) & 0xFF;
800 }
801 i = 0;
802 while (p[i] == 0 && (p[i+1] & 0x80) == 0)
803 i++;
804 memmove(p, p+i, n*2+1-i);
805 *len = n*2+1-i;
806 return p;
807}
808void ssh2_pkt_addmp(Bignum b) {
809 unsigned char *p;
810 int len;
811 p = ssh2_mpint_fmt(b, &len);
812 ssh2_pkt_addstring_start();
813 ssh2_pkt_addstring_data(p, len);
814 free(p);
815}
816void ssh2_pkt_send(void) {
817 int cipherblk, maclen, padding, i;
818 static unsigned long outgoing_sequence = 0;
819
820 /*
821 * Add padding. At least four bytes, and must also bring total
822 * length (minus MAC) up to a multiple of the block size.
823 */
824 cipherblk = cipher ? cipher->blksize : 8; /* block size */
825 cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */
826 padding = 4;
827 padding += (cipherblk - (pktout.length + padding) % cipherblk) % cipherblk;
828 pktout.data[4] = padding;
829 for (i = 0; i < padding; i++)
830 pktout.data[pktout.length + i] = random_byte();
831 PUT_32BIT(pktout.data, pktout.length + padding - 4);
832 if (csmac)
833 csmac->generate(pktout.data, pktout.length + padding,
834 outgoing_sequence);
835 outgoing_sequence++; /* whether or not we MACed */
836
837#if 0
838 debug(("Sending packet len=%d\r\n", pktout.length+padding));
839 for (i = 0; i < pktout.length+padding; i++)
840 debug((" %02x", (unsigned char)pktout.data[i]));
841 debug(("\r\n"));
842#endif
843
844 if (cscipher)
845 cscipher->encrypt(pktout.data, pktout.length + padding);
846 maclen = csmac ? csmac->len : 0;
847
848 s_write(pktout.data, pktout.length + padding + maclen);
849}
850
851#if 0
852void bndebug(char *string, Bignum b) {
853 unsigned char *p;
854 int i, len;
855 p = ssh2_mpint_fmt(b, &len);
856 debug(("%s", string));
857 for (i = 0; i < len; i++)
858 debug((" %02x", p[i]));
859 debug(("\r\n"));
860 free(p);
861}
862#endif
863
864void sha_mpint(SHA_State *s, Bignum b) {
865 unsigned char *p;
866 int len;
867 p = ssh2_mpint_fmt(b, &len);
868 sha_string(s, p, len);
869 free(p);
870}
871
872/*
873 * SSH2 packet decode functions.
874 */
875unsigned long ssh2_pkt_getuint32(void) {
876 unsigned long value;
877 if (pktin.length - pktin.savedpos < 4)
878 return 0; /* arrgh, no way to decline (FIXME?) */
879 value = GET_32BIT(pktin.data+pktin.savedpos);
880 pktin.savedpos += 4;
881 return value;
882}
883void ssh2_pkt_getstring(char **p, int *length) {
884 *p = NULL;
885 if (pktin.length - pktin.savedpos < 4)
886 return;
887 *length = GET_32BIT(pktin.data+pktin.savedpos);
888 pktin.savedpos += 4;
889 if (pktin.length - pktin.savedpos < *length)
890 return;
891 *p = pktin.data+pktin.savedpos;
892 pktin.savedpos += *length;
893}
894Bignum ssh2_pkt_getmp(void) {
895 char *p;
896 int i, j, length;
897 Bignum b;
898
899 ssh2_pkt_getstring(&p, &length);
900 if (!p)
901 return NULL;
902 if (p[0] & 0x80)
903 fatalbox("internal error: Can't handle negative mpints");
904 b = newbn((length+1)/2);
905 for (i = 0; i < length; i++) {
906 j = length - 1 - i;
907 if (j & 1)
908 b[j/2+1] |= ((unsigned char)p[i]) << 8;
909 else
910 b[j/2+1] |= ((unsigned char)p[i]);
911 }
912 return b;
913}
914
374330e2 915static int do_ssh_init(void) {
c5e9c988 916 char c, *vsp;
374330e2 917 char version[10];
c5e9c988 918 char vstring[80];
919 char vlog[sizeof(vstring)+20];
374330e2 920 int i;
921
922#ifdef FWHACK
923 i = 0;
924 while (s_read(&c, 1) == 1) {
925 if (c == 'S' && i < 2) i++;
926 else if (c == 'S' && i == 2) i = 2;
927 else if (c == 'H' && i == 2) break;
928 else i = 0;
929 }
930#else
931 if (s_read(&c,1) != 1 || c != 'S') return 0;
932 if (s_read(&c,1) != 1 || c != 'S') return 0;
933 if (s_read(&c,1) != 1 || c != 'H') return 0;
934#endif
c5e9c988 935 strcpy(vstring, "SSH-");
936 vsp = vstring+4;
374330e2 937 if (s_read(&c,1) != 1 || c != '-') return 0;
938 i = 0;
939 while (1) {
940 if (s_read(&c,1) != 1)
941 return 0;
c5e9c988 942 if (vsp < vstring+sizeof(vstring)-1)
943 *vsp++ = c;
374330e2 944 if (i >= 0) {
945 if (c == '-') {
946 version[i] = '\0';
947 i = -1;
948 } else if (i < sizeof(version)-1)
949 version[i++] = c;
950 }
951 else if (c == '\n')
952 break;
953 }
954
c5e9c988 955 *vsp = 0;
956 sprintf(vlog, "Server version: %s", vstring);
957 vlog[strcspn(vlog, "\r\n")] = '\0';
958 logevent(vlog);
959
7cca0d81 960 if (ssh_versioncmp(version, "2.0" /* FIXME: "1.99" */ ) >= 0) {
e5574168 961 /*
962 * This is a v2 server. Begin v2 protocol.
963 */
964 char *verstring = "SSH-2.0-PuTTY";
965 SHA_Init(&exhash);
966 /*
967 * Hash our version string and their version string.
968 */
969 sha_string(&exhash, verstring, strlen(verstring));
970 sha_string(&exhash, vstring, strcspn(vstring, "\r\n"));
971 sprintf(vstring, "%s\n", verstring);
972 sprintf(vlog, "We claim version: %s", verstring);
973 logevent(vlog);
974 logevent("Using SSH protocol version 2");
975 s_write(vstring, strlen(vstring));
976 ssh_protocol = ssh2_protocol;
6abbf9e3 977 ssh_version = 2;
e5574168 978 s_rdpkt = ssh2_rdpkt;
979 } else {
980 /*
981 * This is a v1 server. Begin v1 protocol.
982 */
983 sprintf(vstring, "SSH-%s-PuTTY\n",
984 (ssh_versioncmp(version, "1.5") <= 0 ? version : "1.5"));
985 sprintf(vlog, "We claim version: %s", vstring);
986 vlog[strcspn(vlog, "\r\n")] = '\0';
987 logevent(vlog);
988 logevent("Using SSH protocol version 1");
989 s_write(vstring, strlen(vstring));
990 ssh_protocol = ssh1_protocol;
6abbf9e3 991 ssh_version = 1;
e5574168 992 s_rdpkt = ssh1_rdpkt;
993 }
8ccc75b0 994 ssh_send_ok = 0;
fef97f43 995 return 1;
374330e2 996}
997
fb09bf1c 998/*
999 * Handle the key exchange and user authentication phases.
1000 */
e5574168 1001static int do_ssh1_login(unsigned char *in, int inlen, int ispkt)
fb09bf1c 1002{
374330e2 1003 int i, j, len;
374330e2 1004 unsigned char *rsabuf, *keystr1, *keystr2;
1005 unsigned char cookie[8];
1006 struct RSAKey servkey, hostkey;
1007 struct MD5Context md5c;
ccbfb941 1008 static unsigned long supported_ciphers_mask, supported_auths_mask;
7cca0d81 1009 static int tried_publickey;
1010 static unsigned char session_id[16];
bea1ef5f 1011 int cipher_type;
374330e2 1012
374330e2 1013 crBegin;
1014
fb09bf1c 1015 if (!ispkt) crWaitUntil(ispkt);
374330e2 1016
e5574168 1017 if (pktin.type != SSH1_SMSG_PUBLIC_KEY)
374330e2 1018 fatalbox("Public key packet not received");
1019
c5e9c988 1020 logevent("Received public keys");
374330e2 1021
c5e9c988 1022 memcpy(cookie, pktin.body, 8);
374330e2 1023
7cca0d81 1024 i = makekey(pktin.body+8, &servkey, &keystr1, 0);
1025 j = makekey(pktin.body+8+i, &hostkey, &keystr2, 0);
374330e2 1026
c5e9c988 1027 /*
1028 * Hash the host key and print the hash in the log box. Just as
1029 * a last resort in case the registry's host key checking is
1030 * compromised, we'll allow the user some ability to verify
1031 * host keys by eye.
1032 */
1033 MD5Init(&md5c);
1034 MD5Update(&md5c, keystr2, hostkey.bytes);
1035 MD5Final(session_id, &md5c);
1036 {
1037 char logmsg[80];
1038 int i;
1039 logevent("Host key MD5 is:");
1040 strcpy(logmsg, " ");
1041 for (i = 0; i < 16; i++)
1042 sprintf(logmsg+strlen(logmsg), "%02x", session_id[i]);
1043 logevent(logmsg);
1044 }
1045
fb09bf1c 1046 supported_ciphers_mask = GET_32BIT(pktin.body+12+i+j);
1047 supported_auths_mask = GET_32BIT(pktin.body+16+i+j);
bea1ef5f 1048
c5e9c988 1049 MD5Init(&md5c);
374330e2 1050 MD5Update(&md5c, keystr2, hostkey.bytes);
1051 MD5Update(&md5c, keystr1, servkey.bytes);
1052 MD5Update(&md5c, pktin.body, 8);
374330e2 1053 MD5Final(session_id, &md5c);
1054
1055 for (i=0; i<32; i++)
1056 session_key[i] = random_byte();
1057
1058 len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes);
1059
1060 rsabuf = malloc(len);
1061 if (!rsabuf)
1062 fatalbox("Out of memory");
1063
89ee5268 1064 /*
1065 * Verify the host key.
1066 */
1067 {
1068 /*
1069 * First format the key into a string.
1070 */
1071 int len = rsastr_len(&hostkey);
1072 char *keystr = malloc(len);
1073 if (!keystr)
1074 fatalbox("Out of memory");
1075 rsastr_fmt(keystr, &hostkey);
1076 verify_ssh_host_key(savedhost, keystr);
1077 free(keystr);
1078 }
374330e2 1079
1080 for (i=0; i<32; i++) {
1081 rsabuf[i] = session_key[i];
1082 if (i < 16)
1083 rsabuf[i] ^= session_id[i];
1084 }
1085
1086 if (hostkey.bytes > servkey.bytes) {
1087 rsaencrypt(rsabuf, 32, &servkey);
1088 rsaencrypt(rsabuf, servkey.bytes, &hostkey);
1089 } else {
1090 rsaencrypt(rsabuf, 32, &hostkey);
1091 rsaencrypt(rsabuf, hostkey.bytes, &servkey);
1092 }
1093
c5e9c988 1094 logevent("Encrypted session key");
1095
bea1ef5f 1096 cipher_type = cfg.cipher == CIPHER_BLOWFISH ? SSH_CIPHER_BLOWFISH :
9697bfd2 1097 cfg.cipher == CIPHER_DES ? SSH_CIPHER_DES :
bea1ef5f 1098 SSH_CIPHER_3DES;
1099 if ((supported_ciphers_mask & (1 << cipher_type)) == 0) {
1100 c_write("Selected cipher not supported, falling back to 3DES\r\n", 53);
1101 cipher_type = SSH_CIPHER_3DES;
1102 }
c5e9c988 1103 switch (cipher_type) {
1104 case SSH_CIPHER_3DES: logevent("Using 3DES encryption"); break;
1105 case SSH_CIPHER_DES: logevent("Using single-DES encryption"); break;
1106 case SSH_CIPHER_BLOWFISH: logevent("Using Blowfish encryption"); break;
1107 }
bea1ef5f 1108
e5574168 1109 send_packet(SSH1_CMSG_SESSION_KEY,
fb09bf1c 1110 PKT_CHAR, cipher_type,
1111 PKT_DATA, cookie, 8,
1112 PKT_CHAR, (len*8) >> 8, PKT_CHAR, (len*8) & 0xFF,
1113 PKT_DATA, rsabuf, len,
1114 PKT_INT, 0,
1115 PKT_END);
1116
c5e9c988 1117 logevent("Trying to enable encryption...");
374330e2 1118
1119 free(rsabuf);
1120
bea1ef5f 1121 cipher = cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish :
9697bfd2 1122 cipher_type == SSH_CIPHER_DES ? &ssh_des :
bea1ef5f 1123 &ssh_3des;
374330e2 1124 cipher->sesskey(session_key);
1125
fb09bf1c 1126 crWaitUntil(ispkt);
374330e2 1127
e5574168 1128 if (pktin.type != SSH1_SMSG_SUCCESS)
374330e2 1129 fatalbox("Encryption not successfully enabled");
1130
c5e9c988 1131 logevent("Successfully started encryption");
1132
374330e2 1133 fflush(stdout);
1134 {
1135 static char username[100];
1136 static int pos = 0;
1137 static char c;
4017be6d 1138 if (!(flags & FLAG_CONNECTION) && !*cfg.username) {
374330e2 1139 c_write("login as: ", 10);
1140 while (pos >= 0) {
fb09bf1c 1141 crWaitUntil(!ispkt);
374330e2 1142 while (inlen--) switch (c = *in++) {
1143 case 10: case 13:
1144 username[pos] = 0;
1145 pos = -1;
1146 break;
1147 case 8: case 127:
1148 if (pos > 0) {
1149 c_write("\b \b", 3);
1150 pos--;
1151 }
1152 break;
1153 case 21: case 27:
1154 while (pos > 0) {
1155 c_write("\b \b", 3);
1156 pos--;
1157 }
1158 break;
1159 case 3: case 4:
1160 random_save_seed();
1161 exit(0);
1162 break;
1163 default:
40d24aa6 1164 if (((c >= ' ' && c <= '~') ||
1165 ((unsigned char)c >= 160)) && pos < 40) {
374330e2 1166 username[pos++] = c;
1167 c_write(&c, 1);
1168 }
1169 break;
1170 }
1171 }
1172 c_write("\r\n", 2);
1173 username[strcspn(username, "\n\r")] = '\0';
1174 } else {
1175 char stuff[200];
1176 strncpy(username, cfg.username, 99);
1177 username[99] = '\0';
4017be6d 1178 if (flags & FLAG_VERBOSE) {
fb09bf1c 1179 sprintf(stuff, "Sent username \"%s\".\r\n", username);
4017be6d 1180 c_write(stuff, strlen(stuff));
fb09bf1c 1181 }
374330e2 1182 }
fb09bf1c 1183
e5574168 1184 send_packet(SSH1_CMSG_USER, PKT_STR, username, PKT_END);
c5e9c988 1185 {
1186 char userlog[20+sizeof(username)];
1187 sprintf(userlog, "Sent username \"%s\"", username);
1188 logevent(userlog);
1189 }
374330e2 1190 }
1191
fb09bf1c 1192 crWaitUntil(ispkt);
374330e2 1193
7cca0d81 1194 tried_publickey = 0;
1195
e5574168 1196 while (pktin.type == SSH1_SMSG_FAILURE) {
374330e2 1197 static char password[100];
1198 static int pos;
1199 static char c;
ccbfb941 1200 static int pwpkt_type;
ccbfb941 1201 /*
1202 * Show password prompt, having first obtained it via a TIS
1203 * exchange if we're doing TIS authentication.
1204 */
e5574168 1205 pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
7cca0d81 1206 if (*cfg.keyfile && !tried_publickey)
1207 pwpkt_type = SSH1_CMSG_AUTH_RSA;
fb09bf1c 1208
4017be6d 1209 if (pwpkt_type == SSH1_CMSG_AUTH_PASSWORD && !FLAG_WINDOWED) {
fb09bf1c 1210 char prompt[200];
1211 sprintf(prompt, "%s@%s's password: ", cfg.username, savedhost);
85ee8208 1212 if (!ssh_get_password(prompt, password, sizeof(password))) {
1213 /*
1214 * get_password failed to get a password (for
1215 * example because one was supplied on the command
1216 * line which has already failed to work).
1217 * Terminate.
1218 */
1219 logevent("No more passwords to try");
1220 ssh_state = SSH_STATE_CLOSED;
1221 crReturn(1);
1222 }
fb09bf1c 1223 } else {
1224
7cca0d81 1225 if (pktin.type == SSH1_SMSG_FAILURE &&
1226 cfg.try_tis_auth &&
1227 (supported_auths_mask & (1<<SSH1_AUTH_TIS))) {
1228 pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
1229 logevent("Requested TIS authentication");
1230 send_packet(SSH1_CMSG_AUTH_TIS, PKT_END);
1231 crWaitUntil(ispkt);
1232 if (pktin.type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
1233 logevent("TIS authentication declined");
1234 c_write("TIS authentication refused.\r\n", 29);
1235 } else {
1236 int challengelen = ((pktin.body[0] << 24) |
1237 (pktin.body[1] << 16) |
1238 (pktin.body[2] << 8) |
1239 (pktin.body[3]));
1240 logevent("Received TIS challenge");
1241 c_write(pktin.body+4, challengelen);
1242 }
1243 }
1244 if (pwpkt_type == SSH1_CMSG_AUTH_PASSWORD)
1245 c_write("password: ", 10);
1246 if (pwpkt_type == SSH1_CMSG_AUTH_RSA) {
4017be6d 1247 if (flags & FLAG_VERBOSE)
1248 c_write("Trying public key authentication.\r\n", 35);
7cca0d81 1249 if (!rsakey_encrypted(cfg.keyfile)) {
4017be6d 1250 if (flags & FLAG_VERBOSE)
1251 c_write("No passphrase required.\r\n", 25);
7cca0d81 1252 goto tryauth;
1253 }
1254 c_write("passphrase: ", 12);
ccbfb941 1255 }
ccbfb941 1256
7cca0d81 1257 pos = 0;
1258 while (pos >= 0) {
1259 crWaitUntil(!ispkt);
1260 while (inlen--) switch (c = *in++) {
1261 case 10: case 13:
1262 password[pos] = 0;
1263 pos = -1;
1264 break;
1265 case 8: case 127:
1266 if (pos > 0)
1267 pos--;
1268 break;
1269 case 21: case 27:
1270 pos = 0;
1271 break;
1272 case 3: case 4:
1273 random_save_seed();
1274 exit(0);
1275 break;
1276 default:
1277 if (((c >= ' ' && c <= '~') ||
1278 ((unsigned char)c >= 160)) && pos < sizeof(password))
1279 password[pos++] = c;
1280 break;
1281 }
1282 }
1283 c_write("\r\n", 2);
fb09bf1c 1284
1285 }
1286
7cca0d81 1287 tryauth:
1288 if (pwpkt_type == SSH1_CMSG_AUTH_RSA) {
1289 /*
1290 * Try public key authentication with the specified
1291 * key file.
1292 */
1293 static struct RSAKey pubkey;
1294 static Bignum challenge, response;
1295 static int i;
1296 static unsigned char buffer[32];
1297
1298 tried_publickey = 1;
1299 i = loadrsakey(cfg.keyfile, &pubkey, password);
1300 if (i == 0) {
1301 c_write("Couldn't load public key from ", 30);
1302 c_write(cfg.keyfile, strlen(cfg.keyfile));
1303 c_write(".\r\n", 3);
1304 continue; /* go and try password */
1305 }
1306 if (i == -1) {
1307 c_write("Wrong passphrase.\r\n", 19);
1308 tried_publickey = 0;
1309 continue; /* try again */
1310 }
1311
1312 /*
1313 * Send a public key attempt.
1314 */
1315 send_packet(SSH1_CMSG_AUTH_RSA,
1316 PKT_BIGNUM, pubkey.modulus, PKT_END);
1317
1318 crWaitUntil(ispkt);
1319 if (pktin.type == SSH1_SMSG_FAILURE) {
4017be6d 1320 if (flags & FLAG_VERBOSE)
1321 c_write("Server refused our public key.\r\n", 32);
7cca0d81 1322 continue; /* go and try password */
1323 }
1324 if (pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE)
1325 fatalbox("Bizarre response to offer of public key");
1326 ssh1_read_bignum(pktin.body, &challenge);
1327 response = rsadecrypt(challenge, &pubkey);
1328 freebn(pubkey.private_exponent); /* burn the evidence */
1329
1330 for (i = 0; i < 32; i += 2) {
1331 buffer[i] = response[16-i/2] >> 8;
1332 buffer[i+1] = response[16-i/2] & 0xFF;
1333 }
1334
1335 MD5Init(&md5c);
1336 MD5Update(&md5c, buffer, 32);
1337 MD5Update(&md5c, session_id, 16);
1338 MD5Final(buffer, &md5c);
1339
1340 send_packet(SSH1_CMSG_AUTH_RSA_RESPONSE,
1341 PKT_DATA, buffer, 16, PKT_END);
1342
1343 crWaitUntil(ispkt);
1344 if (pktin.type == SSH1_SMSG_FAILURE) {
4017be6d 1345 if (flags & FLAG_VERBOSE)
1346 c_write("Failed to authenticate with our public key.\r\n",
1347 45);
7cca0d81 1348 continue; /* go and try password */
1349 } else if (pktin.type != SSH1_SMSG_SUCCESS) {
1350 fatalbox("Bizarre response to RSA authentication response");
1351 }
1352
1353 break; /* we're through! */
1354 } else {
1355 send_packet(pwpkt_type, PKT_STR, password, PKT_END);
1356 }
c5e9c988 1357 logevent("Sent password");
374330e2 1358 memset(password, 0, strlen(password));
fb09bf1c 1359 crWaitUntil(ispkt);
e5574168 1360 if (pktin.type == SSH1_SMSG_FAILURE) {
4017be6d 1361 if (flags & FLAG_VERBOSE)
1362 c_write("Access denied\r\n", 15);
c5e9c988 1363 logevent("Authentication refused");
e5574168 1364 } else if (pktin.type == SSH1_MSG_DISCONNECT) {
fb09bf1c 1365 logevent("Received disconnect request");
85ee8208 1366 ssh_state = SSH_STATE_CLOSED;
1367 crReturn(1);
e5574168 1368 } else if (pktin.type != SSH1_SMSG_SUCCESS) {
374330e2 1369 fatalbox("Strange packet received, type %d", pktin.type);
1370 }
1371 }
1372
c5e9c988 1373 logevent("Authentication successful");
1374
fb09bf1c 1375 crFinish(1);
1376}
1377
e5574168 1378static void ssh1_protocol(unsigned char *in, int inlen, int ispkt) {
fb09bf1c 1379 crBegin;
1380
1381 random_init();
1382
e5574168 1383 while (!do_ssh1_login(in, inlen, ispkt)) {
fb09bf1c 1384 crReturnV;
85ee8208 1385 }
1386 if (ssh_state == SSH_STATE_CLOSED)
1387 crReturnV;
fb09bf1c 1388
fef97f43 1389 if (!cfg.nopty) {
e5574168 1390 send_packet(SSH1_CMSG_REQUEST_PTY,
fb09bf1c 1391 PKT_STR, cfg.termtype,
1392 PKT_INT, rows, PKT_INT, cols,
1393 PKT_INT, 0, PKT_INT, 0,
1394 PKT_CHAR, 0,
1395 PKT_END);
fef97f43 1396 ssh_state = SSH_STATE_INTERMED;
1397 do { crReturnV; } while (!ispkt);
e5574168 1398 if (pktin.type != SSH1_SMSG_SUCCESS && pktin.type != SSH1_SMSG_FAILURE) {
fef97f43 1399 fatalbox("Protocol confusion");
e5574168 1400 } else if (pktin.type == SSH1_SMSG_FAILURE) {
fef97f43 1401 c_write("Server refused to allocate pty\r\n", 32);
1402 }
c5e9c988 1403 logevent("Allocated pty");
374330e2 1404 }
1405
6abbf9e3 1406 if (*cfg.remote_cmd)
1407 send_packet(SSH1_CMSG_EXEC_CMD, PKT_STR, cfg.remote_cmd, PKT_END);
1408 else
1409 send_packet(SSH1_CMSG_EXEC_SHELL, PKT_END);
c5e9c988 1410 logevent("Started session");
374330e2 1411
1412 ssh_state = SSH_STATE_SESSION;
1413 if (size_needed)
1414 ssh_size();
1415
8ccc75b0 1416 ssh_send_ok = 1;
374330e2 1417 while (1) {
1418 crReturnV;
1419 if (ispkt) {
e5574168 1420 if (pktin.type == SSH1_SMSG_STDOUT_DATA ||
1421 pktin.type == SSH1_SMSG_STDERR_DATA) {
fb09bf1c 1422 long len = GET_32BIT(pktin.body);
1423 c_write(pktin.body+4, len);
e5574168 1424 } else if (pktin.type == SSH1_MSG_DISCONNECT) {
21248260 1425 ssh_state = SSH_STATE_CLOSED;
c5e9c988 1426 logevent("Received disconnect request");
e5574168 1427 } else if (pktin.type == SSH1_SMSG_SUCCESS) {
972a41c8 1428 /* may be from EXEC_SHELL on some servers */
e5574168 1429 } else if (pktin.type == SSH1_SMSG_FAILURE) {
972a41c8 1430 /* may be from EXEC_SHELL on some servers
374330e2 1431 * if no pty is available or in other odd cases. Ignore */
e5574168 1432 } else if (pktin.type == SSH1_SMSG_EXIT_STATUS) {
1433 send_packet(SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
374330e2 1434 } else {
1435 fatalbox("Strange packet received: type %d", pktin.type);
1436 }
1437 } else {
e5574168 1438 send_packet(SSH1_CMSG_STDIN_DATA,
fb09bf1c 1439 PKT_INT, inlen, PKT_DATA, in, inlen, PKT_END);
374330e2 1440 }
1441 }
1442
1443 crFinishV;
1444}
1445
1446/*
e5574168 1447 * Utility routine for decoding comma-separated strings in KEXINIT.
1448 */
1449int in_commasep_string(char *needle, char *haystack, int haylen) {
1450 int needlen = strlen(needle);
1451 while (1) {
1452 /*
1453 * Is it at the start of the string?
1454 */
1455 if (haylen >= needlen && /* haystack is long enough */
1456 !memcmp(needle, haystack, needlen) && /* initial match */
1457 (haylen == needlen || haystack[needlen] == ',')
1458 /* either , or EOS follows */
1459 )
1460 return 1;
1461 /*
1462 * If not, search for the next comma and resume after that.
1463 * If no comma found, terminate.
1464 */
1465 while (haylen > 0 && *haystack != ',')
1466 haylen--, haystack++;
1467 if (haylen == 0)
1468 return 0;
1469 haylen--, haystack++; /* skip over comma itself */
1470 }
1471}
1472
1473/*
d39f364a 1474 * SSH2 key creation method.
1475 */
1476void ssh2_mkkey(Bignum K, char *H, char chr, char *keyspace) {
1477 SHA_State s;
1478 /* First 20 bytes. */
1479 SHA_Init(&s);
1480 sha_mpint(&s, K);
1481 SHA_Bytes(&s, H, 20);
1482 SHA_Bytes(&s, &chr, 1);
1483 SHA_Bytes(&s, H, 20);
1484 SHA_Final(&s, keyspace);
1485 /* Next 20 bytes. */
1486 SHA_Init(&s);
1487 sha_mpint(&s, K);
1488 SHA_Bytes(&s, H, 20);
1489 SHA_Bytes(&s, keyspace, 20);
1490 SHA_Final(&s, keyspace+20);
1491}
1492
1493/*
7cca0d81 1494 * Handle the SSH2 transport layer.
e5574168 1495 */
7cca0d81 1496static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt)
e5574168 1497{
1498 static int i, len;
1499 static char *str;
1500 static Bignum e, f, K;
1501 static struct ssh_cipher *cscipher_tobe = NULL;
1502 static struct ssh_cipher *sccipher_tobe = NULL;
1503 static struct ssh_mac *csmac_tobe = NULL;
1504 static struct ssh_mac *scmac_tobe = NULL;
1505 static struct ssh_compress *cscomp_tobe = NULL;
1506 static struct ssh_compress *sccomp_tobe = NULL;
7cca0d81 1507 static char *hostkeydata, *sigdata, *keystr;
e5574168 1508 static int hostkeylen, siglen;
1509 static unsigned char exchange_hash[20];
d39f364a 1510 static unsigned char keyspace[40];
e5574168 1511
1512 crBegin;
7cca0d81 1513 random_init();
e5574168 1514
7cca0d81 1515 begin_key_exchange:
e5574168 1516 /*
1517 * Construct and send our key exchange packet.
1518 */
1519 ssh2_pkt_init(SSH2_MSG_KEXINIT);
1520 for (i = 0; i < 16; i++)
1521 ssh2_pkt_addbyte((unsigned char)random_byte());
1522 /* List key exchange algorithms. */
1523 ssh2_pkt_addstring_start();
1524 for (i = 0; i < lenof(kex_algs); i++) {
1525 ssh2_pkt_addstring_str(kex_algs[i]->name);
1526 if (i < lenof(kex_algs)-1)
1527 ssh2_pkt_addstring_str(",");
1528 }
1529 /* List server host key algorithms. */
1530 ssh2_pkt_addstring_start();
1531 for (i = 0; i < lenof(hostkey_algs); i++) {
1532 ssh2_pkt_addstring_str(hostkey_algs[i]->name);
1533 if (i < lenof(hostkey_algs)-1)
1534 ssh2_pkt_addstring_str(",");
1535 }
1536 /* List client->server encryption algorithms. */
1537 ssh2_pkt_addstring_start();
1538 for (i = 0; i < lenof(ciphers); i++) {
1539 ssh2_pkt_addstring_str(ciphers[i]->name);
1540 if (i < lenof(ciphers)-1)
1541 ssh2_pkt_addstring_str(",");
1542 }
1543 /* List server->client encryption algorithms. */
1544 ssh2_pkt_addstring_start();
1545 for (i = 0; i < lenof(ciphers); i++) {
1546 ssh2_pkt_addstring_str(ciphers[i]->name);
1547 if (i < lenof(ciphers)-1)
1548 ssh2_pkt_addstring_str(",");
1549 }
1550 /* List client->server MAC algorithms. */
1551 ssh2_pkt_addstring_start();
1552 for (i = 0; i < lenof(macs); i++) {
1553 ssh2_pkt_addstring_str(macs[i]->name);
1554 if (i < lenof(macs)-1)
1555 ssh2_pkt_addstring_str(",");
1556 }
1557 /* List server->client MAC algorithms. */
1558 ssh2_pkt_addstring_start();
1559 for (i = 0; i < lenof(macs); i++) {
1560 ssh2_pkt_addstring_str(macs[i]->name);
1561 if (i < lenof(macs)-1)
1562 ssh2_pkt_addstring_str(",");
1563 }
1564 /* List client->server compression algorithms. */
1565 ssh2_pkt_addstring_start();
1566 for (i = 0; i < lenof(compressions); i++) {
1567 ssh2_pkt_addstring_str(compressions[i]->name);
1568 if (i < lenof(compressions)-1)
1569 ssh2_pkt_addstring_str(",");
1570 }
1571 /* List server->client compression algorithms. */
1572 ssh2_pkt_addstring_start();
1573 for (i = 0; i < lenof(compressions); i++) {
1574 ssh2_pkt_addstring_str(compressions[i]->name);
1575 if (i < lenof(compressions)-1)
1576 ssh2_pkt_addstring_str(",");
1577 }
1578 /* List client->server languages. Empty list. */
1579 ssh2_pkt_addstring_start();
1580 /* List server->client languages. Empty list. */
1581 ssh2_pkt_addstring_start();
1582 /* First KEX packet does _not_ follow, because we're not that brave. */
1583 ssh2_pkt_addbool(FALSE);
1584 /* Reserved. */
1585 ssh2_pkt_adduint32(0);
1586 sha_string(&exhash, pktout.data+5, pktout.length-5);
1587 ssh2_pkt_send();
1588
1589 if (!ispkt) crWaitUntil(ispkt);
1590 sha_string(&exhash, pktin.data+5, pktin.length-5);
1591
1592 /*
1593 * Now examine the other side's KEXINIT to see what we're up
1594 * to.
1595 */
7cca0d81 1596 if (pktin.type != SSH2_MSG_KEXINIT) {
e5574168 1597 fatalbox("expected key exchange packet from server");
7cca0d81 1598 }
e5574168 1599 kex = NULL; hostkey = NULL; cscipher_tobe = NULL; sccipher_tobe = NULL;
1600 csmac_tobe = NULL; scmac_tobe = NULL; cscomp_tobe = NULL; sccomp_tobe = NULL;
1601 pktin.savedpos += 16; /* skip garbage cookie */
1602 ssh2_pkt_getstring(&str, &len); /* key exchange algorithms */
1603 for (i = 0; i < lenof(kex_algs); i++) {
1604 if (in_commasep_string(kex_algs[i]->name, str, len)) {
1605 kex = kex_algs[i];
1606 break;
1607 }
1608 }
1609 ssh2_pkt_getstring(&str, &len); /* host key algorithms */
1610 for (i = 0; i < lenof(hostkey_algs); i++) {
1611 if (in_commasep_string(hostkey_algs[i]->name, str, len)) {
1612 hostkey = hostkey_algs[i];
1613 break;
1614 }
1615 }
1616 ssh2_pkt_getstring(&str, &len); /* client->server cipher */
1617 for (i = 0; i < lenof(ciphers); i++) {
1618 if (in_commasep_string(ciphers[i]->name, str, len)) {
1619 cscipher_tobe = ciphers[i];
1620 break;
1621 }
1622 }
1623 ssh2_pkt_getstring(&str, &len); /* server->client cipher */
1624 for (i = 0; i < lenof(ciphers); i++) {
1625 if (in_commasep_string(ciphers[i]->name, str, len)) {
1626 sccipher_tobe = ciphers[i];
1627 break;
1628 }
1629 }
1630 ssh2_pkt_getstring(&str, &len); /* client->server mac */
1631 for (i = 0; i < lenof(macs); i++) {
1632 if (in_commasep_string(macs[i]->name, str, len)) {
1633 csmac_tobe = macs[i];
1634 break;
1635 }
1636 }
1637 ssh2_pkt_getstring(&str, &len); /* server->client mac */
1638 for (i = 0; i < lenof(macs); i++) {
1639 if (in_commasep_string(macs[i]->name, str, len)) {
1640 scmac_tobe = macs[i];
1641 break;
1642 }
1643 }
1644 ssh2_pkt_getstring(&str, &len); /* client->server compression */
1645 for (i = 0; i < lenof(compressions); i++) {
1646 if (in_commasep_string(compressions[i]->name, str, len)) {
1647 cscomp_tobe = compressions[i];
1648 break;
1649 }
1650 }
1651 ssh2_pkt_getstring(&str, &len); /* server->client compression */
1652 for (i = 0; i < lenof(compressions); i++) {
1653 if (in_commasep_string(compressions[i]->name, str, len)) {
1654 sccomp_tobe = compressions[i];
1655 break;
1656 }
1657 }
e5574168 1658
1659 /*
1660 * Currently we only support Diffie-Hellman and DSS, so let's
1661 * bomb out if those aren't selected.
1662 */
1663 if (kex != &ssh_diffiehellman || hostkey != &ssh_dss)
1664 fatalbox("internal fault: chaos in SSH 2 transport layer");
1665
1666 /*
1667 * Now we begin the fun. Generate and send e for Diffie-Hellman.
1668 */
1669 e = dh_create_e();
e5574168 1670 ssh2_pkt_init(SSH2_MSG_KEXDH_INIT);
1671 ssh2_pkt_addmp(e);
1672 ssh2_pkt_send();
1673
1674 crWaitUntil(ispkt);
7cca0d81 1675 if (pktin.type != SSH2_MSG_KEXDH_REPLY) {
e5574168 1676 fatalbox("expected key exchange packet from server");
7cca0d81 1677 }
e5574168 1678 ssh2_pkt_getstring(&hostkeydata, &hostkeylen);
1679 f = ssh2_pkt_getmp();
e5574168 1680 ssh2_pkt_getstring(&sigdata, &siglen);
1681
1682 K = dh_find_K(f);
e5574168 1683
1684 sha_string(&exhash, hostkeydata, hostkeylen);
1685 sha_mpint(&exhash, e);
1686 sha_mpint(&exhash, f);
1687 sha_mpint(&exhash, K);
1688 SHA_Final(&exhash, exchange_hash);
1689
7cca0d81 1690#if 0
e5574168 1691 debug(("Exchange hash is:\r\n"));
1692 for (i = 0; i < 20; i++)
1693 debug((" %02x", exchange_hash[i]));
1694 debug(("\r\n"));
7cca0d81 1695#endif
1696
1697 hostkey->setkey(hostkeydata, hostkeylen);
1698 if (!hostkey->verifysig(sigdata, siglen, exchange_hash, 20))
1699 fatalbox("Server failed host key check");
e5574168 1700
1701 /*
7cca0d81 1702 * Expect SSH2_MSG_NEWKEYS from server.
d39f364a 1703 */
7cca0d81 1704 crWaitUntil(ispkt);
1705 if (pktin.type != SSH2_MSG_NEWKEYS)
1706 fatalbox("expected new-keys packet from server");
d39f364a 1707
1708 /*
7cca0d81 1709 * Authenticate remote host: verify host key. (We've already
1710 * checked the signature of the exchange hash.)
e5574168 1711 */
7cca0d81 1712 keystr = hostkey->fmtkey();
1713 verify_ssh_host_key(savedhost, keystr);
1714 free(keystr);
d39f364a 1715
1716 /*
7cca0d81 1717 * Send SSH2_MSG_NEWKEYS.
d39f364a 1718 */
1719 ssh2_pkt_init(SSH2_MSG_NEWKEYS);
1720 ssh2_pkt_send();
d39f364a 1721
1722 /*
1723 * Create and initialise session keys.
1724 */
1725 cscipher = cscipher_tobe;
1726 sccipher = sccipher_tobe;
1727 csmac = csmac_tobe;
1728 scmac = scmac_tobe;
1729 cscomp = cscomp_tobe;
1730 sccomp = sccomp_tobe;
1731 /*
1732 * Set IVs after keys.
1733 */
1734 ssh2_mkkey(K, exchange_hash, 'C', keyspace); cscipher->setcskey(keyspace);
1735 ssh2_mkkey(K, exchange_hash, 'D', keyspace); cscipher->setsckey(keyspace);
1736 ssh2_mkkey(K, exchange_hash, 'A', keyspace); cscipher->setcsiv(keyspace);
1737 ssh2_mkkey(K, exchange_hash, 'B', keyspace); sccipher->setsciv(keyspace);
1738 ssh2_mkkey(K, exchange_hash, 'E', keyspace); csmac->setcskey(keyspace);
1739 ssh2_mkkey(K, exchange_hash, 'F', keyspace); scmac->setsckey(keyspace);
1740
033b4cef 1741 /*
7cca0d81 1742 * Now we're encrypting. Begin returning 1 to the protocol main
1743 * function so that other things can run on top of the
1744 * transport. If we ever see a KEXINIT, we must go back to the
1745 * start.
033b4cef 1746 */
7cca0d81 1747 do {
1748 crReturn(1);
1749 } while (!(ispkt && pktin.type == SSH2_MSG_KEXINIT));
1750 goto begin_key_exchange;
e5574168 1751
1752 crFinish(1);
1753}
1754
7cca0d81 1755/*
6abbf9e3 1756 * SSH2: remote identifier for the main session channel.
1757 */
1758static unsigned long ssh_remote_channel;
1759
1760/*
7cca0d81 1761 * Handle the SSH2 userauth and connection layers.
1762 */
1763static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt)
1764{
7cca0d81 1765 static unsigned long remote_winsize;
1766 static unsigned long remote_maxpkt;
1767
e5574168 1768 crBegin;
1769
7cca0d81 1770 /*
1771 * Request userauth protocol, and await a response to it.
1772 */
1773 ssh2_pkt_init(SSH2_MSG_SERVICE_REQUEST);
1774 ssh2_pkt_addstring("ssh-userauth");
1775 ssh2_pkt_send();
1776 crWaitUntilV(ispkt);
1777 if (pktin.type != SSH2_MSG_SERVICE_ACCEPT)
1778 fatalbox("Server refused user authentication protocol");
1779
1780 /*
1781 * FIXME: currently we support only password authentication.
1782 * (This places us technically in violation of the SSH2 spec.
1783 * We must fix this.)
1784 */
1785 while (1) {
1786 /*
1787 * Get a username and a password.
1788 */
1789 static char username[100];
1790 static char password[100];
1791 static int pos = 0;
1792 static char c;
e5574168 1793
4017be6d 1794 if ((flags & FLAG_CONNECTION) && !*cfg.username) {
7cca0d81 1795 c_write("login as: ", 10);
1796 while (pos >= 0) {
1797 crWaitUntilV(!ispkt);
1798 while (inlen--) switch (c = *in++) {
1799 case 10: case 13:
1800 username[pos] = 0;
1801 pos = -1;
1802 break;
1803 case 8: case 127:
1804 if (pos > 0) {
1805 c_write("\b \b", 3);
1806 pos--;
1807 }
1808 break;
1809 case 21: case 27:
1810 while (pos > 0) {
1811 c_write("\b \b", 3);
1812 pos--;
1813 }
1814 break;
1815 case 3: case 4:
1816 random_save_seed();
1817 exit(0);
1818 break;
1819 default:
1820 if (((c >= ' ' && c <= '~') ||
1821 ((unsigned char)c >= 160)) && pos < 40) {
1822 username[pos++] = c;
1823 c_write(&c, 1);
1824 }
1825 break;
1826 }
1827 }
1828 c_write("\r\n", 2);
1829 username[strcspn(username, "\n\r")] = '\0';
1830 } else {
1831 char stuff[200];
1832 strncpy(username, cfg.username, 99);
1833 username[99] = '\0';
4017be6d 1834 if (flags & FLAG_VERBOSE) {
7cca0d81 1835 sprintf(stuff, "Using username \"%s\".\r\n", username);
1836 c_write(stuff, strlen(stuff));
1837 }
1838 }
1839
4017be6d 1840 if (!(flags & FLAG_WINDOWED)) {
7cca0d81 1841 char prompt[200];
1842 sprintf(prompt, "%s@%s's password: ", cfg.username, savedhost);
1843 if (!ssh_get_password(prompt, password, sizeof(password))) {
1844 /*
1845 * get_password failed to get a password (for
1846 * example because one was supplied on the command
1847 * line which has already failed to work).
1848 * Terminate.
1849 */
1850 logevent("No more passwords to try");
1851 ssh_state = SSH_STATE_CLOSED;
1852 crReturnV;
1853 }
1854 } else {
1855 c_write("password: ", 10);
1856
1857 pos = 0;
1858 while (pos >= 0) {
1859 crWaitUntilV(!ispkt);
1860 while (inlen--) switch (c = *in++) {
1861 case 10: case 13:
1862 password[pos] = 0;
1863 pos = -1;
1864 break;
1865 case 8: case 127:
1866 if (pos > 0)
1867 pos--;
1868 break;
1869 case 21: case 27:
1870 pos = 0;
1871 break;
1872 case 3: case 4:
1873 random_save_seed();
1874 exit(0);
1875 break;
1876 default:
1877 if (((c >= ' ' && c <= '~') ||
1878 ((unsigned char)c >= 160)) && pos < 40)
1879 password[pos++] = c;
1880 break;
1881 }
1882 }
1883 c_write("\r\n", 2);
1884 }
1885
1886 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
1887 ssh2_pkt_addstring(username);
1888 ssh2_pkt_addstring("ssh-connection"); /* service requested */
1889 ssh2_pkt_addstring("password");
1890 ssh2_pkt_addbool(FALSE);
1891 ssh2_pkt_addstring(password);
1892 ssh2_pkt_send();
1893
1894 crWaitUntilV(ispkt);
1895 if (pktin.type != SSH2_MSG_USERAUTH_SUCCESS) {
1896 c_write("Access denied\r\n", 15);
1897 logevent("Authentication refused");
1898 } else
1899 break;
1900 }
1901
1902 /*
1903 * Now we're authenticated for the connection protocol. The
1904 * connection protocol will automatically have started at this
1905 * point; there's no need to send SERVICE_REQUEST.
1906 */
1907
1908 /*
1909 * So now create a channel with a session in it.
1910 */
1911 ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN);
1912 ssh2_pkt_addstring("session");
1913 ssh2_pkt_adduint32(100); /* as good as any */
1914 ssh2_pkt_adduint32(0xFFFFFFFFUL); /* very big window which we ignore */
1915 ssh2_pkt_adduint32(0xFFFFFFFFUL); /* very big max pkt size */
1916 ssh2_pkt_send();
1917 crWaitUntilV(ispkt);
1918 if (pktin.type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
1919 fatalbox("Server refused to open a session");
1920 /* FIXME: error data comes back in FAILURE packet */
1921 }
1922 if (ssh2_pkt_getuint32() != 100) {
1923 fatalbox("Server's channel confirmation cited wrong channel");
1924 }
6abbf9e3 1925 ssh_remote_channel = ssh2_pkt_getuint32();
7cca0d81 1926 remote_winsize = ssh2_pkt_getuint32();
1927 remote_maxpkt = ssh2_pkt_getuint32();
1928 logevent("Opened channel for session");
1929
1930 /*
1931 * Now allocate a pty for the session.
1932 */
1933 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
6abbf9e3 1934 ssh2_pkt_adduint32(ssh_remote_channel); /* recipient channel */
7cca0d81 1935 ssh2_pkt_addstring("pty-req");
1936 ssh2_pkt_addbool(1); /* want reply */
1937 ssh2_pkt_addstring(cfg.termtype);
1938 ssh2_pkt_adduint32(cols);
1939 ssh2_pkt_adduint32(rows);
1940 ssh2_pkt_adduint32(0); /* pixel width */
1941 ssh2_pkt_adduint32(0); /* pixel height */
1942 ssh2_pkt_addstring_start();
1943 ssh2_pkt_addstring_data("\0", 1); /* TTY_OP_END, no special options */
1944 ssh2_pkt_send();
1945
1946 do { /* FIXME: pay attention to these */
1947 crWaitUntilV(ispkt);
1948 } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1949
1950 if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
1951 if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
1952 fatalbox("Server got confused by pty request");
1953 }
1954 c_write("Server refused to allocate pty\r\n", 32);
1955 } else {
1956 logevent("Allocated pty");
1957 }
1958
1959 /*
1960 * Start a shell.
1961 */
1962 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
6abbf9e3 1963 ssh2_pkt_adduint32(ssh_remote_channel); /* recipient channel */
7cca0d81 1964 ssh2_pkt_addstring("shell");
1965 ssh2_pkt_addbool(1); /* want reply */
1966 ssh2_pkt_send();
1967 do { /* FIXME: pay attention to these */
1968 crWaitUntilV(ispkt);
1969 } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1970 if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
1971 if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
1972 fatalbox("Server got confused by shell request");
1973 }
1974 fatalbox("Server refused to start a shell");
1975 } else {
1976 logevent("Started a shell");
1977 }
1978
1979 /*
1980 * Transfer data!
1981 */
8ccc75b0 1982 ssh_send_ok = 1;
7cca0d81 1983 while (1) {
e5574168 1984 crReturnV;
7cca0d81 1985 if (ispkt) {
1986 if (pktin.type == SSH2_MSG_CHANNEL_DATA ||
1987 pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA) {
1988 char *data;
1989 int length;
1990 if (ssh2_pkt_getuint32() != 100)
1991 continue; /* wrong channel */
1992 if (pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
1993 ssh2_pkt_getuint32() != SSH2_EXTENDED_DATA_STDERR)
1994 continue; /* extended but not stderr */
1995 ssh2_pkt_getstring(&data, &length);
1996 if (data)
1997 c_write(data, length);
1998 } else if (pktin.type == SSH2_MSG_DISCONNECT) {
1999 ssh_state = SSH_STATE_CLOSED;
2000 logevent("Received disconnect request");
2001 } else if (pktin.type == SSH2_MSG_CHANNEL_REQUEST) {
2002 continue; /* exit status et al; ignore (FIXME?) */
2003 } else if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
2004 continue; /* ignore for now (FIXME!) */
2005 } else {
2006 fatalbox("Strange packet received: type %d", pktin.type);
2007 }
2008 } else {
2009 /* FIXME: for now, ignore window size */
2010 ssh2_pkt_init(SSH2_MSG_CHANNEL_DATA);
6abbf9e3 2011 ssh2_pkt_adduint32(ssh_remote_channel);
7cca0d81 2012 ssh2_pkt_addstring_start();
2013 ssh2_pkt_addstring_data(in, inlen);
2014 ssh2_pkt_send();
2015 }
e5574168 2016 }
2017
2018 crFinishV;
2019}
2020
2021/*
7cca0d81 2022 * Handle the top-level SSH2 protocol.
2023 */
2024static void ssh2_protocol(unsigned char *in, int inlen, int ispkt)
2025{
2026 if (do_ssh2_transport(in, inlen, ispkt) == 0)
2027 return;
2028 do_ssh2_authconn(in, inlen, ispkt);
2029}
2030
2031/*
374330e2 2032 * Called to set up the connection. Will arrange for WM_NETEVENT
2033 * messages to be passed to the specified window, whose window
2034 * procedure should then call telnet_msg().
2035 *
2036 * Returns an error message, or NULL on success.
374330e2 2037 */
2038static char *ssh_init (HWND hwnd, char *host, int port, char **realhost) {
fb09bf1c 2039 char *p;
8f203108 2040
2041#ifdef MSCRYPTOAPI
2042 if(crypto_startup() == 0)
2043 return "Microsoft high encryption pack not installed!";
2044#endif
374330e2 2045
fb09bf1c 2046 p = connect_to_host(host, port, realhost);
2047 if (p != NULL)
2048 return p;
374330e2 2049
2050 if (!do_ssh_init())
2051 return "Protocol initialisation error";
2052
4017be6d 2053 if (hwnd && WSAAsyncSelect (s, hwnd, WM_NETEVENT, FD_READ | FD_CLOSE) == SOCKET_ERROR)
374330e2 2054 switch (WSAGetLastError()) {
2055 case WSAENETDOWN: return "Network is down";
2056 default: return "WSAAsyncSelect(): unknown error";
2057 }
2058
2059 return NULL;
2060}
2061
2062/*
2063 * Process a WM_NETEVENT message. Will return 0 if the connection
2064 * has closed, or <0 for a socket error.
2065 */
2066static int ssh_msg (WPARAM wParam, LPARAM lParam) {
2067 int ret;
2068 char buf[256];
2069
8ce72d2c 2070 /*
2071 * Because reading less than the whole of the available pending
2072 * data can generate an FD_READ event, we need to allow for the
2073 * possibility that FD_READ may arrive with FD_CLOSE already in
2074 * the queue; so it's possible that we can get here even with s
2075 * invalid. If so, we return 1 and don't worry about it.
2076 */
2077 if (s == INVALID_SOCKET)
2078 return 1;
374330e2 2079
2080 if (WSAGETSELECTERROR(lParam) != 0)
2081 return -WSAGETSELECTERROR(lParam);
2082
2083 switch (WSAGETSELECTEVENT(lParam)) {
2084 case FD_READ:
8ce72d2c 2085 case FD_CLOSE:
374330e2 2086 ret = recv(s, buf, sizeof(buf), 0);
2087 if (ret < 0 && WSAGetLastError() == WSAEWOULDBLOCK)
2088 return 1;
2089 if (ret < 0) /* any _other_ error */
2090 return -10000-WSAGetLastError();
2091 if (ret == 0) {
2092 s = INVALID_SOCKET;
8ce72d2c 2093 return 0;
374330e2 2094 }
2095 ssh_gotdata (buf, ret);
85ee8208 2096 if (ssh_state == SSH_STATE_CLOSED) {
2097 closesocket(s);
2098 s = INVALID_SOCKET;
2099 return 0;
2100 }
374330e2 2101 return 1;
374330e2 2102 }
2103 return 1; /* shouldn't happen, but WTF */
2104}
2105
2106/*
2107 * Called to send data down the Telnet connection.
2108 */
2109static void ssh_send (char *buf, int len) {
2110 if (s == INVALID_SOCKET)
2111 return;
2112
2113 ssh_protocol(buf, len, 0);
2114}
2115
2116/*
2117 * Called to set the size of the window from Telnet's POV.
2118 */
2119static void ssh_size(void) {
2120 switch (ssh_state) {
2121 case SSH_STATE_BEFORE_SIZE:
21248260 2122 case SSH_STATE_CLOSED:
374330e2 2123 break; /* do nothing */
2124 case SSH_STATE_INTERMED:
2125 size_needed = TRUE; /* buffer for later */
2126 break;
2127 case SSH_STATE_SESSION:
fef97f43 2128 if (!cfg.nopty) {
e5574168 2129 send_packet(SSH1_CMSG_WINDOW_SIZE,
fb09bf1c 2130 PKT_INT, rows, PKT_INT, cols,
2131 PKT_INT, 0, PKT_INT, 0, PKT_END);
fef97f43 2132 }
374330e2 2133 }
2134}
2135
2136/*
6abbf9e3 2137 * Send Telnet special codes. TS_EOF is useful for `plink', so you
2138 * can send an EOF and collect resulting output (e.g. `plink
2139 * hostname sort').
374330e2 2140 */
2141static void ssh_special (Telnet_Special code) {
6abbf9e3 2142 if (code == TS_EOF) {
2143 if (ssh_version = 1) {
2144 send_packet(SSH1_CMSG_EOF, PKT_END);
2145 } else {
2146 ssh2_pkt_init(SSH2_MSG_CHANNEL_EOF);
2147 ssh2_pkt_adduint32(ssh_remote_channel);
2148 ssh2_pkt_send();
2149 }
2150 } else {
2151 /* do nothing */
2152 }
374330e2 2153}
2154
fb09bf1c 2155
2156/*
2157 * Read and decrypt one incoming SSH packet.
2158 * (only used by pSCP)
2159 */
2160static void get_packet(void)
2161{
2162 unsigned char buf[4096], *p;
2163 long to_read;
2164 int len;
2165
fb09bf1c 2166 p = NULL;
2167 len = 0;
2168
2169 while ((to_read = s_rdpkt(&p, &len)) > 0) {
2170 if (to_read > sizeof(buf)) to_read = sizeof(buf);
2171 len = s_read(buf, to_read);
2172 if (len != to_read) {
2173 closesocket(s);
2174 s = INVALID_SOCKET;
2175 return;
2176 }
2177 p = buf;
2178 }
2179
2180 assert(len == 0);
2181}
2182
2183/*
2184 * Receive a block of data over the SSH link. Block until
2185 * all data is available. Return nr of bytes read (0 if lost connection).
2186 * (only used by pSCP)
2187 */
2188int ssh_scp_recv(unsigned char *buf, int len)
2189{
2190 static int pending_input_len = 0;
2191 static unsigned char *pending_input_ptr;
2192 int to_read = len;
2193
fb09bf1c 2194 if (pending_input_len >= to_read) {
2195 memcpy(buf, pending_input_ptr, to_read);
2196 pending_input_ptr += to_read;
2197 pending_input_len -= to_read;
2198 return len;
2199 }
2200
2201 if (pending_input_len > 0) {
2202 memcpy(buf, pending_input_ptr, pending_input_len);
2203 buf += pending_input_len;
2204 to_read -= pending_input_len;
2205 pending_input_len = 0;
2206 }
2207
2208 if (s == INVALID_SOCKET)
2209 return 0;
2210 while (to_read > 0) {
2211 get_packet();
2212 if (s == INVALID_SOCKET)
2213 return 0;
e5574168 2214 if (pktin.type == SSH1_SMSG_STDOUT_DATA) {
fb09bf1c 2215 int plen = GET_32BIT(pktin.body);
2216 if (plen <= to_read) {
2217 memcpy(buf, pktin.body + 4, plen);
2218 buf += plen;
2219 to_read -= plen;
2220 } else {
2221 memcpy(buf, pktin.body + 4, to_read);
2222 pending_input_len = plen - to_read;
2223 pending_input_ptr = pktin.body + 4 + to_read;
2224 to_read = 0;
2225 }
e5574168 2226 } else if (pktin.type == SSH1_SMSG_STDERR_DATA) {
fb09bf1c 2227 int plen = GET_32BIT(pktin.body);
2228 fwrite(pktin.body + 4, plen, 1, stderr);
e5574168 2229 } else if (pktin.type == SSH1_MSG_DISCONNECT) {
fb09bf1c 2230 logevent("Received disconnect request");
e5574168 2231 } else if (pktin.type == SSH1_SMSG_SUCCESS ||
2232 pktin.type == SSH1_SMSG_FAILURE) {
fb09bf1c 2233 /* ignore */
e5574168 2234 } else if (pktin.type == SSH1_SMSG_EXIT_STATUS) {
fb09bf1c 2235 char logbuf[100];
2236 sprintf(logbuf, "Remote exit status: %d", GET_32BIT(pktin.body));
2237 logevent(logbuf);
e5574168 2238 send_packet(SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
fb09bf1c 2239 logevent("Closing connection");
2240 closesocket(s);
2241 s = INVALID_SOCKET;
2242 } else {
2243 fatalbox("Strange packet received: type %d", pktin.type);
2244 }
2245 }
2246
2247 return len;
2248}
2249
2250/*
2251 * Send a block of data over the SSH link.
2252 * Block until all data is sent.
2253 * (only used by pSCP)
2254 */
2255void ssh_scp_send(unsigned char *buf, int len)
2256{
fb09bf1c 2257 if (s == INVALID_SOCKET)
2258 return;
e5574168 2259 send_packet(SSH1_CMSG_STDIN_DATA,
fb09bf1c 2260 PKT_INT, len, PKT_DATA, buf, len, PKT_END);
2261}
2262
2263/*
2264 * Send an EOF notification to the server.
2265 * (only used by pSCP)
2266 */
2267void ssh_scp_send_eof(void)
2268{
fb09bf1c 2269 if (s == INVALID_SOCKET)
2270 return;
e5574168 2271 send_packet(SSH1_CMSG_EOF, PKT_END);
fb09bf1c 2272}
2273
2274/*
2275 * Set up the connection, login on the remote host and
2276 * start execution of a command.
2277 * Returns an error message, or NULL on success.
2278 * (only used by pSCP)
2279 */
2280char *ssh_scp_init(char *host, int port, char *cmd, char **realhost)
2281{
2282 char buf[160], *p;
2283
fb09bf1c 2284#ifdef MSCRYPTOAPI
2285 if (crypto_startup() == 0)
2286 return "Microsoft high encryption pack not installed!";
2287#endif
2288
2289 p = connect_to_host(host, port, realhost);
2290 if (p != NULL)
2291 return p;
2292
2293 random_init();
2294
2295 if (!do_ssh_init())
2296 return "Protocol initialisation error";
2297
2298 /* Exchange keys and login */
2299 do {
2300 get_packet();
2301 if (s == INVALID_SOCKET)
2302 return "Connection closed by remote host";
e5574168 2303 } while (!do_ssh1_login(NULL, 0, 1));
85ee8208 2304
2305 if (ssh_state == SSH_STATE_CLOSED) {
2306 closesocket(s);
2307 s = INVALID_SOCKET;
2308 return "Session initialisation error";
2309 }
fb09bf1c 2310
2311 /* Execute command */
2312 sprintf(buf, "Sending command: %.100s", cmd);
2313 logevent(buf);
e5574168 2314 send_packet(SSH1_CMSG_EXEC_CMD, PKT_STR, cmd, PKT_END);
fb09bf1c 2315
2316 return NULL;
2317}
2318
8ccc75b0 2319static SOCKET ssh_socket(void) { return s; }
2320
2321static int ssh_sendok(void) { return ssh_send_ok; }
fb09bf1c 2322
374330e2 2323Backend ssh_backend = {
2324 ssh_init,
2325 ssh_msg,
2326 ssh_send,
2327 ssh_size,
4017be6d 2328 ssh_special,
8ccc75b0 2329 ssh_socket,
2330 ssh_sendok
374330e2 2331};
Local modifications for Simon Tatham's `PuTTY' SSH client and terminal emulator