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Public key authentication now works in pscp too - oops
[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); \
19 if (IS_SCP && (scp_flags & SCP_VERBOSE) != 0) \
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;
fb09bf1c 163int scp_flags = 0;
85ee8208 164int (*ssh_get_password)(const char *prompt, char *str, int maxlen) = NULL;
374330e2 165
166static char *savedhost;
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);
fb09bf1c 180 if (IS_SCP) {
181 noise_ultralight(i);
182 if (i <= 0)
183 fatalbox("Lost connection while sending");
184 }
374330e2 185 if (i > 0)
186 len -= i, buf += i;
187 }
188}
189
190static int s_read (char *buf, int len) {
191 int ret = 0;
192 while (len > 0) {
193 int i = recv (s, buf, len, 0);
fb09bf1c 194 if (IS_SCP)
195 noise_ultralight(i);
374330e2 196 if (i > 0)
197 len -= i, buf += i, ret += i;
198 else
199 return i;
200 }
201 return ret;
202}
203
204static void c_write (char *buf, int len) {
fb09bf1c 205 if (IS_SCP) {
206 if (len > 0 && buf[len-1] == '\n') len--;
207 if (len > 0 && buf[len-1] == '\r') len--;
208 if (len > 0) { fwrite(buf, len, 1, stderr); fputc('\n', stderr); }
209 return;
210 }
c9def1b8 211 while (len--)
212 c_write1(*buf++);
374330e2 213}
214
215struct Packet {
216 long length;
217 int type;
374330e2 218 unsigned char *data;
219 unsigned char *body;
e5574168 220 long savedpos;
374330e2 221 long maxlen;
222};
223
fb09bf1c 224static struct Packet pktin = { 0, 0, NULL, NULL, 0 };
225static struct Packet pktout = { 0, 0, NULL, NULL, 0 };
374330e2 226
e5574168 227static void (*ssh_protocol)(unsigned char *in, int inlen, int ispkt);
228static void ssh1_protocol(unsigned char *in, int inlen, int ispkt);
229static void ssh2_protocol(unsigned char *in, int inlen, int ispkt);
374330e2 230static void ssh_size(void);
231
e5574168 232static int (*s_rdpkt)(unsigned char **data, int *datalen);
fb09bf1c 233
234/*
235 * Collect incoming data in the incoming packet buffer.
e5574168 236 * Decipher and verify the packet when it is completely read.
237 * Drop SSH1_MSG_DEBUG and SSH1_MSG_IGNORE packets.
fb09bf1c 238 * Update the *data and *datalen variables.
239 * Return the additional nr of bytes needed, or 0 when
240 * a complete packet is available.
241 */
e5574168 242static int ssh1_rdpkt(unsigned char **data, int *datalen)
fb09bf1c 243{
244 static long len, pad, biglen, to_read;
572f871e 245 static unsigned long realcrc, gotcrc;
fb09bf1c 246 static unsigned char *p;
247 static int i;
374330e2 248
249 crBegin;
374330e2 250
fb09bf1c 251next_packet:
37508af4 252
fb09bf1c 253 pktin.type = 0;
254 pktin.length = 0;
374330e2 255
fb09bf1c 256 for (i = len = 0; i < 4; i++) {
257 while ((*datalen) == 0)
258 crReturn(4-i);
259 len = (len << 8) + **data;
260 (*data)++, (*datalen)--;
261 }
374330e2 262
fb09bf1c 263#ifdef FWHACK
264 if (len == 0x52656d6f) { /* "Remo"te server has closed ... */
265 len = 0x300; /* big enough to carry to end */
266 }
267#endif
374330e2 268
fb09bf1c 269 pad = 8 - (len % 8);
270 biglen = len + pad;
271 pktin.length = len - 5;
272
273 if (pktin.maxlen < biglen) {
274 pktin.maxlen = biglen;
e5574168 275 pktin.data = (pktin.data == NULL ? malloc(biglen+APIEXTRA) :
276 realloc(pktin.data, biglen+APIEXTRA));
fb09bf1c 277 if (!pktin.data)
278 fatalbox("Out of memory");
279 }
374330e2 280
fb09bf1c 281 to_read = biglen;
282 p = pktin.data;
283 while (to_read > 0) {
284 static int chunk;
285 chunk = to_read;
286 while ((*datalen) == 0)
287 crReturn(to_read);
288 if (chunk > (*datalen))
289 chunk = (*datalen);
290 memcpy(p, *data, chunk);
291 *data += chunk;
292 *datalen -= chunk;
293 p += chunk;
294 to_read -= chunk;
295 }
374330e2 296
fb09bf1c 297 if (cipher)
298 cipher->decrypt(pktin.data, biglen);
374330e2 299
fb09bf1c 300 pktin.type = pktin.data[pad];
301 pktin.body = pktin.data + pad + 1;
374330e2 302
fb09bf1c 303 realcrc = crc32(pktin.data, biglen-4);
304 gotcrc = GET_32BIT(pktin.data+biglen-4);
305 if (gotcrc != realcrc) {
306 fatalbox("Incorrect CRC received on packet");
307 }
572f871e 308
e5574168 309 if (pktin.type == SSH1_SMSG_STDOUT_DATA ||
310 pktin.type == SSH1_SMSG_STDERR_DATA ||
311 pktin.type == SSH1_MSG_DEBUG ||
312 pktin.type == SSH1_SMSG_AUTH_TIS_CHALLENGE) {
fb09bf1c 313 long strlen = GET_32BIT(pktin.body);
314 if (strlen + 4 != pktin.length)
315 fatalbox("Received data packet with bogus string length");
316 }
317
e5574168 318 if (pktin.type == SSH1_MSG_DEBUG) {
fb09bf1c 319 /* log debug message */
320 char buf[80];
321 int strlen = GET_32BIT(pktin.body);
322 strcpy(buf, "Remote: ");
323 if (strlen > 70) strlen = 70;
324 memcpy(buf+8, pktin.body+4, strlen);
325 buf[8+strlen] = '\0';
326 logevent(buf);
327 goto next_packet;
e5574168 328 } else if (pktin.type == SSH1_MSG_IGNORE) {
fb09bf1c 329 /* do nothing */
330 goto next_packet;
331 }
332
333 crFinish(0);
334}
335
e5574168 336static int ssh2_rdpkt(unsigned char **data, int *datalen)
337{
338 static long len, pad, payload, packetlen, maclen;
339 static int i;
340 static int cipherblk;
341 static unsigned long incoming_sequence = 0;
342
343 crBegin;
344
345next_packet:
346
347 pktin.type = 0;
348 pktin.length = 0;
349
350 if (cipher)
351 cipherblk = cipher->blksize;
352 else
353 cipherblk = 8;
354 if (cipherblk < 8)
355 cipherblk = 8;
356
357 if (pktin.maxlen < cipherblk) {
358 pktin.maxlen = cipherblk;
359 pktin.data = (pktin.data == NULL ? malloc(cipherblk+APIEXTRA) :
360 realloc(pktin.data, cipherblk+APIEXTRA));
361 if (!pktin.data)
362 fatalbox("Out of memory");
363 }
364
365 /*
366 * Acquire and decrypt the first block of the packet. This will
367 * contain the length and padding details.
368 */
369 for (i = len = 0; i < cipherblk; i++) {
370 while ((*datalen) == 0)
371 crReturn(cipherblk-i);
372 pktin.data[i] = *(*data)++;
373 (*datalen)--;
374 }
375#ifdef FWHACK
376 if (!memcmp(pktin.data, "Remo", 4)) {/* "Remo"te server has closed ... */
377 /* FIXME */
378 }
379#endif
380 if (sccipher)
381 sccipher->decrypt(pktin.data, cipherblk);
382
383 /*
384 * Now get the length and padding figures.
385 */
386 len = GET_32BIT(pktin.data);
387 pad = pktin.data[4];
388
389 /*
390 * This enables us to deduce the payload length.
391 */
392 payload = len - pad - 1;
393
394 pktin.length = payload + 5;
395
396 /*
397 * So now we can work out the total packet length.
398 */
399 packetlen = len + 4;
400 maclen = scmac ? scmac->len : 0;
401
402 /*
403 * Adjust memory allocation if packet is too big.
404 */
405 if (pktin.maxlen < packetlen) {
406 pktin.maxlen = packetlen;
407 pktin.data = (pktin.data == NULL ? malloc(packetlen+APIEXTRA) :
408 realloc(pktin.data, packetlen+APIEXTRA));
409 if (!pktin.data)
410 fatalbox("Out of memory");
411 }
412
413 /*
414 * Read and decrypt the remainder of the packet.
415 */
416 for (i = cipherblk; i < packetlen + maclen; i++) {
417 while ((*datalen) == 0)
418 crReturn(packetlen + maclen - i);
419 pktin.data[i] = *(*data)++;
420 (*datalen)--;
421 }
422 /* Decrypt everything _except_ the MAC. */
423 if (sccipher)
424 sccipher->decrypt(pktin.data + cipherblk, packetlen - cipherblk);
425
7cca0d81 426#if 0
d39f364a 427 debug(("Got packet len=%d pad=%d\r\n", len, pad));
428 for (i = 0; i < packetlen; i++)
429 debug((" %02x", (unsigned char)pktin.data[i]));
430 debug(("\r\n"));
7cca0d81 431#endif
d39f364a 432
e5574168 433 /*
434 * Check the MAC.
435 */
033b4cef 436 if (scmac && !scmac->verify(pktin.data, len+4, incoming_sequence))
e5574168 437 fatalbox("Incorrect MAC received on packet");
033b4cef 438 incoming_sequence++; /* whether or not we MACed */
e5574168 439
440 pktin.savedpos = 6;
441 pktin.type = pktin.data[5];
e5574168 442
7cca0d81 443 if (pktin.type == SSH2_MSG_IGNORE || pktin.type == SSH2_MSG_DEBUG)
444 goto next_packet; /* FIXME: print DEBUG message */
e5574168 445
446 crFinish(0);
447}
448
fb09bf1c 449static void ssh_gotdata(unsigned char *data, int datalen)
450{
451 while (datalen > 0) {
85ee8208 452 if ( s_rdpkt(&data, &datalen) == 0 ) {
374330e2 453 ssh_protocol(NULL, 0, 1);
85ee8208 454 if (ssh_state == SSH_STATE_CLOSED) {
455 return;
456 }
457 }
374330e2 458 }
374330e2 459}
460
fb09bf1c 461
374330e2 462static void s_wrpkt_start(int type, int len) {
463 int pad, biglen;
464
465 len += 5; /* type and CRC */
466 pad = 8 - (len%8);
467 biglen = len + pad;
468
469 pktout.length = len-5;
470 if (pktout.maxlen < biglen) {
471 pktout.maxlen = biglen;
8f203108 472#ifdef MSCRYPTOAPI
fb09bf1c 473 /* Allocate enough buffer space for extra block
8f203108 474 * for MS CryptEncrypt() */
fb09bf1c 475 pktout.data = (pktout.data == NULL ? malloc(biglen+12) :
476 realloc(pktout.data, biglen+12));
8f203108 477#else
c1f5f956 478 pktout.data = (pktout.data == NULL ? malloc(biglen+4) :
479 realloc(pktout.data, biglen+4));
8f203108 480#endif
374330e2 481 if (!pktout.data)
482 fatalbox("Out of memory");
483 }
484
485 pktout.type = type;
486 pktout.body = pktout.data+4+pad+1;
487}
488
489static void s_wrpkt(void) {
490 int pad, len, biglen, i;
491 unsigned long crc;
492
493 len = pktout.length + 5; /* type and CRC */
494 pad = 8 - (len%8);
495 biglen = len + pad;
496
497 pktout.body[-1] = pktout.type;
498 for (i=0; i<pad; i++)
499 pktout.data[i+4] = random_byte();
500 crc = crc32(pktout.data+4, biglen-4);
fb09bf1c 501 PUT_32BIT(pktout.data+biglen, crc);
502 PUT_32BIT(pktout.data, len);
374330e2 503
504 if (cipher)
505 cipher->encrypt(pktout.data+4, biglen);
506
507 s_write(pktout.data, biglen+4);
508}
509
fb09bf1c 510/*
511 * Construct a packet with the specified contents and
512 * send it to the server.
513 */
514static void send_packet(int pkttype, ...)
515{
516 va_list args;
517 unsigned char *p, *argp, argchar;
518 unsigned long argint;
519 int pktlen, argtype, arglen;
7cca0d81 520 Bignum bn;
521 int i;
fb09bf1c 522
523 pktlen = 0;
524 va_start(args, pkttype);
525 while ((argtype = va_arg(args, int)) != PKT_END) {
526 switch (argtype) {
527 case PKT_INT:
528 (void) va_arg(args, int);
529 pktlen += 4;
530 break;
531 case PKT_CHAR:
532 (void) va_arg(args, char);
533 pktlen++;
534 break;
535 case PKT_DATA:
536 (void) va_arg(args, unsigned char *);
537 arglen = va_arg(args, int);
538 pktlen += arglen;
539 break;
540 case PKT_STR:
541 argp = va_arg(args, unsigned char *);
542 arglen = strlen(argp);
543 pktlen += 4 + arglen;
544 break;
7cca0d81 545 case PKT_BIGNUM:
546 bn = va_arg(args, Bignum);
547 i = 16 * bn[0] - 1;
548 while ( i > 0 && (bn[i/16+1] >> (i%16)) == 0 )
549 i--;
550 pktlen += 2 + (i+7)/8;
551 break;
fb09bf1c 552 default:
553 assert(0);
554 }
555 }
556 va_end(args);
557
558 s_wrpkt_start(pkttype, pktlen);
559 p = pktout.body;
560
561 va_start(args, pkttype);
562 while ((argtype = va_arg(args, int)) != PKT_END) {
563 switch (argtype) {
564 case PKT_INT:
565 argint = va_arg(args, int);
566 PUT_32BIT(p, argint);
567 p += 4;
568 break;
569 case PKT_CHAR:
570 argchar = va_arg(args, unsigned char);
571 *p = argchar;
572 p++;
573 break;
574 case PKT_DATA:
575 argp = va_arg(args, unsigned char *);
576 arglen = va_arg(args, int);
577 memcpy(p, argp, arglen);
578 p += arglen;
579 break;
580 case PKT_STR:
581 argp = va_arg(args, unsigned char *);
582 arglen = strlen(argp);
583 PUT_32BIT(p, arglen);
584 memcpy(p + 4, argp, arglen);
585 p += 4 + arglen;
586 break;
7cca0d81 587 case PKT_BIGNUM:
588 bn = va_arg(args, Bignum);
589 i = 16 * bn[0] - 1;
590 while ( i > 0 && (bn[i/16+1] >> (i%16)) == 0 )
591 i--;
592 *p++ = (i >> 8) & 0xFF;
593 *p++ = i & 0xFF;
594 i = (i + 7) / 8;
595 while (i-- > 0) {
596 if (i % 2)
597 *p++ = bn[i/2+1] >> 8;
598 else
599 *p++ = bn[i/2+1] & 0xFF;
600 }
601 break;
fb09bf1c 602 }
603 }
604 va_end(args);
605
606 s_wrpkt();
607}
608
609
610/*
611 * Connect to specified host and port.
612 * Returns an error message, or NULL on success.
613 * Also places the canonical host name into `realhost'.
614 */
615static char *connect_to_host(char *host, int port, char **realhost)
616{
617 SOCKADDR_IN addr;
618 struct hostent *h;
619 unsigned long a;
620#ifdef FWHACK
621 char *FWhost;
622 int FWport;
623#endif
624
625 savedhost = malloc(1+strlen(host));
626 if (!savedhost)
627 fatalbox("Out of memory");
628 strcpy(savedhost, host);
629
630 if (port < 0)
631 port = 22; /* default ssh port */
632
633#ifdef FWHACK
634 FWhost = host;
635 FWport = port;
636 host = FWSTR;
637 port = 23;
638#endif
639
640 /*
641 * Try to find host.
642 */
643 if ( (a = inet_addr(host)) == (unsigned long) INADDR_NONE) {
644 if ( (h = gethostbyname(host)) == NULL)
645 switch (WSAGetLastError()) {
646 case WSAENETDOWN: return "Network is down";
647 case WSAHOST_NOT_FOUND: case WSANO_DATA:
648 return "Host does not exist";
649 case WSATRY_AGAIN: return "Host not found";
650 default: return "gethostbyname: unknown error";
651 }
652 memcpy (&a, h->h_addr, sizeof(a));
653 *realhost = h->h_name;
654 } else
655 *realhost = host;
656#ifdef FWHACK
657 *realhost = FWhost;
658#endif
659 a = ntohl(a);
660
661 /*
662 * Open socket.
663 */
664 s = socket(AF_INET, SOCK_STREAM, 0);
665 if (s == INVALID_SOCKET)
666 switch (WSAGetLastError()) {
667 case WSAENETDOWN: return "Network is down";
668 case WSAEAFNOSUPPORT: return "TCP/IP support not present";
669 default: return "socket(): unknown error";
670 }
671
672 /*
673 * Bind to local address.
674 */
675 addr.sin_family = AF_INET;
676 addr.sin_addr.s_addr = htonl(INADDR_ANY);
677 addr.sin_port = htons(0);
678 if (bind (s, (struct sockaddr *)&addr, sizeof(addr)) == SOCKET_ERROR)
679 switch (WSAGetLastError()) {
680 case WSAENETDOWN: return "Network is down";
681 default: return "bind(): unknown error";
682 }
683
684 /*
685 * Connect to remote address.
686 */
687 addr.sin_addr.s_addr = htonl(a);
688 addr.sin_port = htons((short)port);
689 if (connect (s, (struct sockaddr *)&addr, sizeof(addr)) == SOCKET_ERROR)
690 switch (WSAGetLastError()) {
691 case WSAENETDOWN: return "Network is down";
692 case WSAECONNREFUSED: return "Connection refused";
693 case WSAENETUNREACH: return "Network is unreachable";
694 case WSAEHOSTUNREACH: return "No route to host";
695 default: return "connect(): unknown error";
696 }
697
698#ifdef FWHACK
699 send(s, "connect ", 8, 0);
700 send(s, FWhost, strlen(FWhost), 0);
701 {
702 char buf[20];
703 sprintf(buf, " %d\n", FWport);
704 send (s, buf, strlen(buf), 0);
705 }
706#endif
707
708 return NULL;
709}
710
9697bfd2 711static int ssh_versioncmp(char *a, char *b) {
712 char *ae, *be;
713 unsigned long av, bv;
714
43aa02a7 715 av = strtoul(a, &ae, 10);
716 bv = strtoul(b, &be, 10);
9697bfd2 717 if (av != bv) return (av < bv ? -1 : +1);
718 if (*ae == '.') ae++;
719 if (*be == '.') be++;
43aa02a7 720 av = strtoul(ae, &ae, 10);
721 bv = strtoul(be, &be, 10);
9697bfd2 722 if (av != bv) return (av < bv ? -1 : +1);
723 return 0;
724}
725
e5574168 726
727/*
728 * Utility routine for putting an SSH-protocol `string' into a SHA
729 * state.
730 */
731#include <stdio.h>
732void sha_string(SHA_State *s, void *str, int len) {
733 unsigned char lenblk[4];
734static FILE *fp;
735 PUT_32BIT(lenblk, len);
736if (!fp) fp = fopen("h:\\statham\\windows\\putty\\data","wb");
737fwrite(lenblk, 4, 1, fp);
738 SHA_Bytes(s, lenblk, 4);
739fwrite(str, len, 1, fp);
740fflush(fp);
741 SHA_Bytes(s, str, len);
742}
743
7cca0d81 744/*
745 * SSH2 packet construction functions.
746 */
747void ssh2_pkt_adddata(void *data, int len) {
748 pktout.length += len;
749 if (pktout.maxlen < pktout.length) {
750 pktout.maxlen = pktout.length + 256;
751 pktout.data = (pktout.data == NULL ? malloc(pktout.maxlen+APIEXTRA) :
752 realloc(pktout.data, pktout.maxlen+APIEXTRA));
753 if (!pktout.data)
754 fatalbox("Out of memory");
755 }
756 memcpy(pktout.data+pktout.length-len, data, len);
757}
758void ssh2_pkt_addbyte(unsigned char byte) {
759 ssh2_pkt_adddata(&byte, 1);
760}
761void ssh2_pkt_init(int pkt_type) {
762 pktout.length = 5;
763 ssh2_pkt_addbyte((unsigned char)pkt_type);
764}
765void ssh2_pkt_addbool(unsigned char value) {
766 ssh2_pkt_adddata(&value, 1);
767}
768void ssh2_pkt_adduint32(unsigned long value) {
769 unsigned char x[4];
770 PUT_32BIT(x, value);
771 ssh2_pkt_adddata(x, 4);
772}
773void ssh2_pkt_addstring_start(void) {
774 ssh2_pkt_adduint32(0);
775 pktout.savedpos = pktout.length;
776}
777void ssh2_pkt_addstring_str(char *data) {
778 ssh2_pkt_adddata(data, strlen(data));
779 PUT_32BIT(pktout.data + pktout.savedpos - 4,
780 pktout.length - pktout.savedpos);
781}
782void ssh2_pkt_addstring_data(char *data, int len) {
783 ssh2_pkt_adddata(data, len);
784 PUT_32BIT(pktout.data + pktout.savedpos - 4,
785 pktout.length - pktout.savedpos);
786}
787void ssh2_pkt_addstring(char *data) {
788 ssh2_pkt_addstring_start();
789 ssh2_pkt_addstring_str(data);
790}
791char *ssh2_mpint_fmt(Bignum b, int *len) {
792 unsigned char *p;
793 int i, n = b[0];
794 p = malloc(n * 2 + 1);
795 if (!p)
796 fatalbox("out of memory");
797 p[0] = 0;
798 for (i = 0; i < n; i++) {
799 p[i*2+1] = (b[n-i] >> 8) & 0xFF;
800 p[i*2+2] = (b[n-i] ) & 0xFF;
801 }
802 i = 0;
803 while (p[i] == 0 && (p[i+1] & 0x80) == 0)
804 i++;
805 memmove(p, p+i, n*2+1-i);
806 *len = n*2+1-i;
807 return p;
808}
809void ssh2_pkt_addmp(Bignum b) {
810 unsigned char *p;
811 int len;
812 p = ssh2_mpint_fmt(b, &len);
813 ssh2_pkt_addstring_start();
814 ssh2_pkt_addstring_data(p, len);
815 free(p);
816}
817void ssh2_pkt_send(void) {
818 int cipherblk, maclen, padding, i;
819 static unsigned long outgoing_sequence = 0;
820
821 /*
822 * Add padding. At least four bytes, and must also bring total
823 * length (minus MAC) up to a multiple of the block size.
824 */
825 cipherblk = cipher ? cipher->blksize : 8; /* block size */
826 cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */
827 padding = 4;
828 padding += (cipherblk - (pktout.length + padding) % cipherblk) % cipherblk;
829 pktout.data[4] = padding;
830 for (i = 0; i < padding; i++)
831 pktout.data[pktout.length + i] = random_byte();
832 PUT_32BIT(pktout.data, pktout.length + padding - 4);
833 if (csmac)
834 csmac->generate(pktout.data, pktout.length + padding,
835 outgoing_sequence);
836 outgoing_sequence++; /* whether or not we MACed */
837
838#if 0
839 debug(("Sending packet len=%d\r\n", pktout.length+padding));
840 for (i = 0; i < pktout.length+padding; i++)
841 debug((" %02x", (unsigned char)pktout.data[i]));
842 debug(("\r\n"));
843#endif
844
845 if (cscipher)
846 cscipher->encrypt(pktout.data, pktout.length + padding);
847 maclen = csmac ? csmac->len : 0;
848
849 s_write(pktout.data, pktout.length + padding + maclen);
850}
851
852#if 0
853void bndebug(char *string, Bignum b) {
854 unsigned char *p;
855 int i, len;
856 p = ssh2_mpint_fmt(b, &len);
857 debug(("%s", string));
858 for (i = 0; i < len; i++)
859 debug((" %02x", p[i]));
860 debug(("\r\n"));
861 free(p);
862}
863#endif
864
865void sha_mpint(SHA_State *s, Bignum b) {
866 unsigned char *p;
867 int len;
868 p = ssh2_mpint_fmt(b, &len);
869 sha_string(s, p, len);
870 free(p);
871}
872
873/*
874 * SSH2 packet decode functions.
875 */
876unsigned long ssh2_pkt_getuint32(void) {
877 unsigned long value;
878 if (pktin.length - pktin.savedpos < 4)
879 return 0; /* arrgh, no way to decline (FIXME?) */
880 value = GET_32BIT(pktin.data+pktin.savedpos);
881 pktin.savedpos += 4;
882 return value;
883}
884void ssh2_pkt_getstring(char **p, int *length) {
885 *p = NULL;
886 if (pktin.length - pktin.savedpos < 4)
887 return;
888 *length = GET_32BIT(pktin.data+pktin.savedpos);
889 pktin.savedpos += 4;
890 if (pktin.length - pktin.savedpos < *length)
891 return;
892 *p = pktin.data+pktin.savedpos;
893 pktin.savedpos += *length;
894}
895Bignum ssh2_pkt_getmp(void) {
896 char *p;
897 int i, j, length;
898 Bignum b;
899
900 ssh2_pkt_getstring(&p, &length);
901 if (!p)
902 return NULL;
903 if (p[0] & 0x80)
904 fatalbox("internal error: Can't handle negative mpints");
905 b = newbn((length+1)/2);
906 for (i = 0; i < length; i++) {
907 j = length - 1 - i;
908 if (j & 1)
909 b[j/2+1] |= ((unsigned char)p[i]) << 8;
910 else
911 b[j/2+1] |= ((unsigned char)p[i]);
912 }
913 return b;
914}
915
374330e2 916static int do_ssh_init(void) {
c5e9c988 917 char c, *vsp;
374330e2 918 char version[10];
c5e9c988 919 char vstring[80];
920 char vlog[sizeof(vstring)+20];
374330e2 921 int i;
922
923#ifdef FWHACK
924 i = 0;
925 while (s_read(&c, 1) == 1) {
926 if (c == 'S' && i < 2) i++;
927 else if (c == 'S' && i == 2) i = 2;
928 else if (c == 'H' && i == 2) break;
929 else i = 0;
930 }
931#else
932 if (s_read(&c,1) != 1 || c != 'S') return 0;
933 if (s_read(&c,1) != 1 || c != 'S') return 0;
934 if (s_read(&c,1) != 1 || c != 'H') return 0;
935#endif
c5e9c988 936 strcpy(vstring, "SSH-");
937 vsp = vstring+4;
374330e2 938 if (s_read(&c,1) != 1 || c != '-') return 0;
939 i = 0;
940 while (1) {
941 if (s_read(&c,1) != 1)
942 return 0;
c5e9c988 943 if (vsp < vstring+sizeof(vstring)-1)
944 *vsp++ = c;
374330e2 945 if (i >= 0) {
946 if (c == '-') {
947 version[i] = '\0';
948 i = -1;
949 } else if (i < sizeof(version)-1)
950 version[i++] = c;
951 }
952 else if (c == '\n')
953 break;
954 }
955
c5e9c988 956 *vsp = 0;
957 sprintf(vlog, "Server version: %s", vstring);
958 vlog[strcspn(vlog, "\r\n")] = '\0';
959 logevent(vlog);
960
7cca0d81 961 if (ssh_versioncmp(version, "2.0" /* FIXME: "1.99" */ ) >= 0) {
e5574168 962 /*
963 * This is a v2 server. Begin v2 protocol.
964 */
965 char *verstring = "SSH-2.0-PuTTY";
966 SHA_Init(&exhash);
967 /*
968 * Hash our version string and their version string.
969 */
970 sha_string(&exhash, verstring, strlen(verstring));
971 sha_string(&exhash, vstring, strcspn(vstring, "\r\n"));
972 sprintf(vstring, "%s\n", verstring);
973 sprintf(vlog, "We claim version: %s", verstring);
974 logevent(vlog);
975 logevent("Using SSH protocol version 2");
976 s_write(vstring, strlen(vstring));
977 ssh_protocol = ssh2_protocol;
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;
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;
fb09bf1c 1136 if (!IS_SCP && !*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';
fb09bf1c 1176 if (!IS_SCP) {
1177 sprintf(stuff, "Sent username \"%s\".\r\n", username);
1178 c_write(stuff, strlen(stuff));
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
bb19fd9b 1207 if (pwpkt_type == SSH1_CMSG_AUTH_PASSWORD && IS_SCP) {
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) {
1245 c_write("Trying public key authentication.\r\n", 35);
1246 if (!rsakey_encrypted(cfg.keyfile)) {
1247 c_write("No passphrase required.\r\n", 25);
1248 goto tryauth;
1249 }
1250 c_write("passphrase: ", 12);
ccbfb941 1251 }
ccbfb941 1252
7cca0d81 1253 pos = 0;
1254 while (pos >= 0) {
1255 crWaitUntil(!ispkt);
1256 while (inlen--) switch (c = *in++) {
1257 case 10: case 13:
1258 password[pos] = 0;
1259 pos = -1;
1260 break;
1261 case 8: case 127:
1262 if (pos > 0)
1263 pos--;
1264 break;
1265 case 21: case 27:
1266 pos = 0;
1267 break;
1268 case 3: case 4:
1269 random_save_seed();
1270 exit(0);
1271 break;
1272 default:
1273 if (((c >= ' ' && c <= '~') ||
1274 ((unsigned char)c >= 160)) && pos < sizeof(password))
1275 password[pos++] = c;
1276 break;
1277 }
1278 }
1279 c_write("\r\n", 2);
fb09bf1c 1280
1281 }
1282
7cca0d81 1283 tryauth:
1284 if (pwpkt_type == SSH1_CMSG_AUTH_RSA) {
1285 /*
1286 * Try public key authentication with the specified
1287 * key file.
1288 */
1289 static struct RSAKey pubkey;
1290 static Bignum challenge, response;
1291 static int i;
1292 static unsigned char buffer[32];
1293
1294 tried_publickey = 1;
1295 i = loadrsakey(cfg.keyfile, &pubkey, password);
1296 if (i == 0) {
1297 c_write("Couldn't load public key from ", 30);
1298 c_write(cfg.keyfile, strlen(cfg.keyfile));
1299 c_write(".\r\n", 3);
1300 continue; /* go and try password */
1301 }
1302 if (i == -1) {
1303 c_write("Wrong passphrase.\r\n", 19);
1304 tried_publickey = 0;
1305 continue; /* try again */
1306 }
1307
1308 /*
1309 * Send a public key attempt.
1310 */
1311 send_packet(SSH1_CMSG_AUTH_RSA,
1312 PKT_BIGNUM, pubkey.modulus, PKT_END);
1313
1314 crWaitUntil(ispkt);
1315 if (pktin.type == SSH1_SMSG_FAILURE) {
1316 c_write("Server refused our public key.\r\n", 32);
1317 continue; /* go and try password */
1318 }
1319 if (pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE)
1320 fatalbox("Bizarre response to offer of public key");
1321 ssh1_read_bignum(pktin.body, &challenge);
1322 response = rsadecrypt(challenge, &pubkey);
1323 freebn(pubkey.private_exponent); /* burn the evidence */
1324
1325 for (i = 0; i < 32; i += 2) {
1326 buffer[i] = response[16-i/2] >> 8;
1327 buffer[i+1] = response[16-i/2] & 0xFF;
1328 }
1329
1330 MD5Init(&md5c);
1331 MD5Update(&md5c, buffer, 32);
1332 MD5Update(&md5c, session_id, 16);
1333 MD5Final(buffer, &md5c);
1334
1335 send_packet(SSH1_CMSG_AUTH_RSA_RESPONSE,
1336 PKT_DATA, buffer, 16, PKT_END);
1337
1338 crWaitUntil(ispkt);
1339 if (pktin.type == SSH1_SMSG_FAILURE) {
1340 c_write("Failed to authenticate with our public key.\r\n", 45);
1341 continue; /* go and try password */
1342 } else if (pktin.type != SSH1_SMSG_SUCCESS) {
1343 fatalbox("Bizarre response to RSA authentication response");
1344 }
1345
1346 break; /* we're through! */
1347 } else {
1348 send_packet(pwpkt_type, PKT_STR, password, PKT_END);
1349 }
c5e9c988 1350 logevent("Sent password");
374330e2 1351 memset(password, 0, strlen(password));
fb09bf1c 1352 crWaitUntil(ispkt);
e5574168 1353 if (pktin.type == SSH1_SMSG_FAILURE) {
374330e2 1354 c_write("Access denied\r\n", 15);
c5e9c988 1355 logevent("Authentication refused");
e5574168 1356 } else if (pktin.type == SSH1_MSG_DISCONNECT) {
fb09bf1c 1357 logevent("Received disconnect request");
85ee8208 1358 ssh_state = SSH_STATE_CLOSED;
1359 crReturn(1);
e5574168 1360 } else if (pktin.type != SSH1_SMSG_SUCCESS) {
374330e2 1361 fatalbox("Strange packet received, type %d", pktin.type);
1362 }
1363 }
1364
c5e9c988 1365 logevent("Authentication successful");
1366
fb09bf1c 1367 crFinish(1);
1368}
1369
e5574168 1370static void ssh1_protocol(unsigned char *in, int inlen, int ispkt) {
fb09bf1c 1371 crBegin;
1372
1373 random_init();
1374
e5574168 1375 while (!do_ssh1_login(in, inlen, ispkt)) {
fb09bf1c 1376 crReturnV;
85ee8208 1377 }
1378 if (ssh_state == SSH_STATE_CLOSED)
1379 crReturnV;
fb09bf1c 1380
fef97f43 1381 if (!cfg.nopty) {
e5574168 1382 send_packet(SSH1_CMSG_REQUEST_PTY,
fb09bf1c 1383 PKT_STR, cfg.termtype,
1384 PKT_INT, rows, PKT_INT, cols,
1385 PKT_INT, 0, PKT_INT, 0,
1386 PKT_CHAR, 0,
1387 PKT_END);
fef97f43 1388 ssh_state = SSH_STATE_INTERMED;
1389 do { crReturnV; } while (!ispkt);
e5574168 1390 if (pktin.type != SSH1_SMSG_SUCCESS && pktin.type != SSH1_SMSG_FAILURE) {
fef97f43 1391 fatalbox("Protocol confusion");
e5574168 1392 } else if (pktin.type == SSH1_SMSG_FAILURE) {
fef97f43 1393 c_write("Server refused to allocate pty\r\n", 32);
1394 }
c5e9c988 1395 logevent("Allocated pty");
374330e2 1396 }
1397
e5574168 1398 send_packet(SSH1_CMSG_EXEC_SHELL, PKT_END);
c5e9c988 1399 logevent("Started session");
374330e2 1400
1401 ssh_state = SSH_STATE_SESSION;
1402 if (size_needed)
1403 ssh_size();
1404
1405 while (1) {
1406 crReturnV;
1407 if (ispkt) {
e5574168 1408 if (pktin.type == SSH1_SMSG_STDOUT_DATA ||
1409 pktin.type == SSH1_SMSG_STDERR_DATA) {
fb09bf1c 1410 long len = GET_32BIT(pktin.body);
1411 c_write(pktin.body+4, len);
e5574168 1412 } else if (pktin.type == SSH1_MSG_DISCONNECT) {
21248260 1413 ssh_state = SSH_STATE_CLOSED;
c5e9c988 1414 logevent("Received disconnect request");
e5574168 1415 } else if (pktin.type == SSH1_SMSG_SUCCESS) {
972a41c8 1416 /* may be from EXEC_SHELL on some servers */
e5574168 1417 } else if (pktin.type == SSH1_SMSG_FAILURE) {
972a41c8 1418 /* may be from EXEC_SHELL on some servers
374330e2 1419 * if no pty is available or in other odd cases. Ignore */
e5574168 1420 } else if (pktin.type == SSH1_SMSG_EXIT_STATUS) {
1421 send_packet(SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
374330e2 1422 } else {
1423 fatalbox("Strange packet received: type %d", pktin.type);
1424 }
1425 } else {
e5574168 1426 send_packet(SSH1_CMSG_STDIN_DATA,
fb09bf1c 1427 PKT_INT, inlen, PKT_DATA, in, inlen, PKT_END);
374330e2 1428 }
1429 }
1430
1431 crFinishV;
1432}
1433
1434/*
e5574168 1435 * Utility routine for decoding comma-separated strings in KEXINIT.
1436 */
1437int in_commasep_string(char *needle, char *haystack, int haylen) {
1438 int needlen = strlen(needle);
1439 while (1) {
1440 /*
1441 * Is it at the start of the string?
1442 */
1443 if (haylen >= needlen && /* haystack is long enough */
1444 !memcmp(needle, haystack, needlen) && /* initial match */
1445 (haylen == needlen || haystack[needlen] == ',')
1446 /* either , or EOS follows */
1447 )
1448 return 1;
1449 /*
1450 * If not, search for the next comma and resume after that.
1451 * If no comma found, terminate.
1452 */
1453 while (haylen > 0 && *haystack != ',')
1454 haylen--, haystack++;
1455 if (haylen == 0)
1456 return 0;
1457 haylen--, haystack++; /* skip over comma itself */
1458 }
1459}
1460
1461/*
d39f364a 1462 * SSH2 key creation method.
1463 */
1464void ssh2_mkkey(Bignum K, char *H, char chr, char *keyspace) {
1465 SHA_State s;
1466 /* First 20 bytes. */
1467 SHA_Init(&s);
1468 sha_mpint(&s, K);
1469 SHA_Bytes(&s, H, 20);
1470 SHA_Bytes(&s, &chr, 1);
1471 SHA_Bytes(&s, H, 20);
1472 SHA_Final(&s, keyspace);
1473 /* Next 20 bytes. */
1474 SHA_Init(&s);
1475 sha_mpint(&s, K);
1476 SHA_Bytes(&s, H, 20);
1477 SHA_Bytes(&s, keyspace, 20);
1478 SHA_Final(&s, keyspace+20);
1479}
1480
1481/*
7cca0d81 1482 * Handle the SSH2 transport layer.
e5574168 1483 */
7cca0d81 1484static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt)
e5574168 1485{
1486 static int i, len;
1487 static char *str;
1488 static Bignum e, f, K;
1489 static struct ssh_cipher *cscipher_tobe = NULL;
1490 static struct ssh_cipher *sccipher_tobe = NULL;
1491 static struct ssh_mac *csmac_tobe = NULL;
1492 static struct ssh_mac *scmac_tobe = NULL;
1493 static struct ssh_compress *cscomp_tobe = NULL;
1494 static struct ssh_compress *sccomp_tobe = NULL;
7cca0d81 1495 static char *hostkeydata, *sigdata, *keystr;
e5574168 1496 static int hostkeylen, siglen;
1497 static unsigned char exchange_hash[20];
d39f364a 1498 static unsigned char keyspace[40];
e5574168 1499
1500 crBegin;
7cca0d81 1501 random_init();
e5574168 1502
7cca0d81 1503 begin_key_exchange:
e5574168 1504 /*
1505 * Construct and send our key exchange packet.
1506 */
1507 ssh2_pkt_init(SSH2_MSG_KEXINIT);
1508 for (i = 0; i < 16; i++)
1509 ssh2_pkt_addbyte((unsigned char)random_byte());
1510 /* List key exchange algorithms. */
1511 ssh2_pkt_addstring_start();
1512 for (i = 0; i < lenof(kex_algs); i++) {
1513 ssh2_pkt_addstring_str(kex_algs[i]->name);
1514 if (i < lenof(kex_algs)-1)
1515 ssh2_pkt_addstring_str(",");
1516 }
1517 /* List server host key algorithms. */
1518 ssh2_pkt_addstring_start();
1519 for (i = 0; i < lenof(hostkey_algs); i++) {
1520 ssh2_pkt_addstring_str(hostkey_algs[i]->name);
1521 if (i < lenof(hostkey_algs)-1)
1522 ssh2_pkt_addstring_str(",");
1523 }
1524 /* List client->server encryption algorithms. */
1525 ssh2_pkt_addstring_start();
1526 for (i = 0; i < lenof(ciphers); i++) {
1527 ssh2_pkt_addstring_str(ciphers[i]->name);
1528 if (i < lenof(ciphers)-1)
1529 ssh2_pkt_addstring_str(",");
1530 }
1531 /* List server->client encryption algorithms. */
1532 ssh2_pkt_addstring_start();
1533 for (i = 0; i < lenof(ciphers); i++) {
1534 ssh2_pkt_addstring_str(ciphers[i]->name);
1535 if (i < lenof(ciphers)-1)
1536 ssh2_pkt_addstring_str(",");
1537 }
1538 /* List client->server MAC algorithms. */
1539 ssh2_pkt_addstring_start();
1540 for (i = 0; i < lenof(macs); i++) {
1541 ssh2_pkt_addstring_str(macs[i]->name);
1542 if (i < lenof(macs)-1)
1543 ssh2_pkt_addstring_str(",");
1544 }
1545 /* List server->client MAC algorithms. */
1546 ssh2_pkt_addstring_start();
1547 for (i = 0; i < lenof(macs); i++) {
1548 ssh2_pkt_addstring_str(macs[i]->name);
1549 if (i < lenof(macs)-1)
1550 ssh2_pkt_addstring_str(",");
1551 }
1552 /* List client->server compression algorithms. */
1553 ssh2_pkt_addstring_start();
1554 for (i = 0; i < lenof(compressions); i++) {
1555 ssh2_pkt_addstring_str(compressions[i]->name);
1556 if (i < lenof(compressions)-1)
1557 ssh2_pkt_addstring_str(",");
1558 }
1559 /* List server->client compression algorithms. */
1560 ssh2_pkt_addstring_start();
1561 for (i = 0; i < lenof(compressions); i++) {
1562 ssh2_pkt_addstring_str(compressions[i]->name);
1563 if (i < lenof(compressions)-1)
1564 ssh2_pkt_addstring_str(",");
1565 }
1566 /* List client->server languages. Empty list. */
1567 ssh2_pkt_addstring_start();
1568 /* List server->client languages. Empty list. */
1569 ssh2_pkt_addstring_start();
1570 /* First KEX packet does _not_ follow, because we're not that brave. */
1571 ssh2_pkt_addbool(FALSE);
1572 /* Reserved. */
1573 ssh2_pkt_adduint32(0);
1574 sha_string(&exhash, pktout.data+5, pktout.length-5);
1575 ssh2_pkt_send();
1576
1577 if (!ispkt) crWaitUntil(ispkt);
1578 sha_string(&exhash, pktin.data+5, pktin.length-5);
1579
1580 /*
1581 * Now examine the other side's KEXINIT to see what we're up
1582 * to.
1583 */
7cca0d81 1584 if (pktin.type != SSH2_MSG_KEXINIT) {
e5574168 1585 fatalbox("expected key exchange packet from server");
7cca0d81 1586 }
e5574168 1587 kex = NULL; hostkey = NULL; cscipher_tobe = NULL; sccipher_tobe = NULL;
1588 csmac_tobe = NULL; scmac_tobe = NULL; cscomp_tobe = NULL; sccomp_tobe = NULL;
1589 pktin.savedpos += 16; /* skip garbage cookie */
1590 ssh2_pkt_getstring(&str, &len); /* key exchange algorithms */
1591 for (i = 0; i < lenof(kex_algs); i++) {
1592 if (in_commasep_string(kex_algs[i]->name, str, len)) {
1593 kex = kex_algs[i];
1594 break;
1595 }
1596 }
1597 ssh2_pkt_getstring(&str, &len); /* host key algorithms */
1598 for (i = 0; i < lenof(hostkey_algs); i++) {
1599 if (in_commasep_string(hostkey_algs[i]->name, str, len)) {
1600 hostkey = hostkey_algs[i];
1601 break;
1602 }
1603 }
1604 ssh2_pkt_getstring(&str, &len); /* client->server cipher */
1605 for (i = 0; i < lenof(ciphers); i++) {
1606 if (in_commasep_string(ciphers[i]->name, str, len)) {
1607 cscipher_tobe = ciphers[i];
1608 break;
1609 }
1610 }
1611 ssh2_pkt_getstring(&str, &len); /* server->client cipher */
1612 for (i = 0; i < lenof(ciphers); i++) {
1613 if (in_commasep_string(ciphers[i]->name, str, len)) {
1614 sccipher_tobe = ciphers[i];
1615 break;
1616 }
1617 }
1618 ssh2_pkt_getstring(&str, &len); /* client->server mac */
1619 for (i = 0; i < lenof(macs); i++) {
1620 if (in_commasep_string(macs[i]->name, str, len)) {
1621 csmac_tobe = macs[i];
1622 break;
1623 }
1624 }
1625 ssh2_pkt_getstring(&str, &len); /* server->client mac */
1626 for (i = 0; i < lenof(macs); i++) {
1627 if (in_commasep_string(macs[i]->name, str, len)) {
1628 scmac_tobe = macs[i];
1629 break;
1630 }
1631 }
1632 ssh2_pkt_getstring(&str, &len); /* client->server compression */
1633 for (i = 0; i < lenof(compressions); i++) {
1634 if (in_commasep_string(compressions[i]->name, str, len)) {
1635 cscomp_tobe = compressions[i];
1636 break;
1637 }
1638 }
1639 ssh2_pkt_getstring(&str, &len); /* server->client compression */
1640 for (i = 0; i < lenof(compressions); i++) {
1641 if (in_commasep_string(compressions[i]->name, str, len)) {
1642 sccomp_tobe = compressions[i];
1643 break;
1644 }
1645 }
e5574168 1646
1647 /*
1648 * Currently we only support Diffie-Hellman and DSS, so let's
1649 * bomb out if those aren't selected.
1650 */
1651 if (kex != &ssh_diffiehellman || hostkey != &ssh_dss)
1652 fatalbox("internal fault: chaos in SSH 2 transport layer");
1653
1654 /*
1655 * Now we begin the fun. Generate and send e for Diffie-Hellman.
1656 */
1657 e = dh_create_e();
e5574168 1658 ssh2_pkt_init(SSH2_MSG_KEXDH_INIT);
1659 ssh2_pkt_addmp(e);
1660 ssh2_pkt_send();
1661
1662 crWaitUntil(ispkt);
7cca0d81 1663 if (pktin.type != SSH2_MSG_KEXDH_REPLY) {
e5574168 1664 fatalbox("expected key exchange packet from server");
7cca0d81 1665 }
e5574168 1666 ssh2_pkt_getstring(&hostkeydata, &hostkeylen);
1667 f = ssh2_pkt_getmp();
e5574168 1668 ssh2_pkt_getstring(&sigdata, &siglen);
1669
1670 K = dh_find_K(f);
e5574168 1671
1672 sha_string(&exhash, hostkeydata, hostkeylen);
1673 sha_mpint(&exhash, e);
1674 sha_mpint(&exhash, f);
1675 sha_mpint(&exhash, K);
1676 SHA_Final(&exhash, exchange_hash);
1677
7cca0d81 1678#if 0
e5574168 1679 debug(("Exchange hash is:\r\n"));
1680 for (i = 0; i < 20; i++)
1681 debug((" %02x", exchange_hash[i]));
1682 debug(("\r\n"));
7cca0d81 1683#endif
1684
1685 hostkey->setkey(hostkeydata, hostkeylen);
1686 if (!hostkey->verifysig(sigdata, siglen, exchange_hash, 20))
1687 fatalbox("Server failed host key check");
e5574168 1688
1689 /*
7cca0d81 1690 * Expect SSH2_MSG_NEWKEYS from server.
d39f364a 1691 */
7cca0d81 1692 crWaitUntil(ispkt);
1693 if (pktin.type != SSH2_MSG_NEWKEYS)
1694 fatalbox("expected new-keys packet from server");
d39f364a 1695
1696 /*
7cca0d81 1697 * Authenticate remote host: verify host key. (We've already
1698 * checked the signature of the exchange hash.)
e5574168 1699 */
7cca0d81 1700 keystr = hostkey->fmtkey();
1701 verify_ssh_host_key(savedhost, keystr);
1702 free(keystr);
d39f364a 1703
1704 /*
7cca0d81 1705 * Send SSH2_MSG_NEWKEYS.
d39f364a 1706 */
1707 ssh2_pkt_init(SSH2_MSG_NEWKEYS);
1708 ssh2_pkt_send();
d39f364a 1709
1710 /*
1711 * Create and initialise session keys.
1712 */
1713 cscipher = cscipher_tobe;
1714 sccipher = sccipher_tobe;
1715 csmac = csmac_tobe;
1716 scmac = scmac_tobe;
1717 cscomp = cscomp_tobe;
1718 sccomp = sccomp_tobe;
1719 /*
1720 * Set IVs after keys.
1721 */
1722 ssh2_mkkey(K, exchange_hash, 'C', keyspace); cscipher->setcskey(keyspace);
1723 ssh2_mkkey(K, exchange_hash, 'D', keyspace); cscipher->setsckey(keyspace);
1724 ssh2_mkkey(K, exchange_hash, 'A', keyspace); cscipher->setcsiv(keyspace);
1725 ssh2_mkkey(K, exchange_hash, 'B', keyspace); sccipher->setsciv(keyspace);
1726 ssh2_mkkey(K, exchange_hash, 'E', keyspace); csmac->setcskey(keyspace);
1727 ssh2_mkkey(K, exchange_hash, 'F', keyspace); scmac->setsckey(keyspace);
1728
033b4cef 1729 /*
7cca0d81 1730 * Now we're encrypting. Begin returning 1 to the protocol main
1731 * function so that other things can run on top of the
1732 * transport. If we ever see a KEXINIT, we must go back to the
1733 * start.
033b4cef 1734 */
7cca0d81 1735 do {
1736 crReturn(1);
1737 } while (!(ispkt && pktin.type == SSH2_MSG_KEXINIT));
1738 goto begin_key_exchange;
e5574168 1739
1740 crFinish(1);
1741}
1742
7cca0d81 1743/*
1744 * Handle the SSH2 userauth and connection layers.
1745 */
1746static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt)
1747{
1748 static unsigned long their_channel;
1749 static unsigned long remote_winsize;
1750 static unsigned long remote_maxpkt;
1751
e5574168 1752 crBegin;
1753
7cca0d81 1754 /*
1755 * Request userauth protocol, and await a response to it.
1756 */
1757 ssh2_pkt_init(SSH2_MSG_SERVICE_REQUEST);
1758 ssh2_pkt_addstring("ssh-userauth");
1759 ssh2_pkt_send();
1760 crWaitUntilV(ispkt);
1761 if (pktin.type != SSH2_MSG_SERVICE_ACCEPT)
1762 fatalbox("Server refused user authentication protocol");
1763
1764 /*
1765 * FIXME: currently we support only password authentication.
1766 * (This places us technically in violation of the SSH2 spec.
1767 * We must fix this.)
1768 */
1769 while (1) {
1770 /*
1771 * Get a username and a password.
1772 */
1773 static char username[100];
1774 static char password[100];
1775 static int pos = 0;
1776 static char c;
e5574168 1777
7cca0d81 1778 if (!IS_SCP && !*cfg.username) {
1779 c_write("login as: ", 10);
1780 while (pos >= 0) {
1781 crWaitUntilV(!ispkt);
1782 while (inlen--) switch (c = *in++) {
1783 case 10: case 13:
1784 username[pos] = 0;
1785 pos = -1;
1786 break;
1787 case 8: case 127:
1788 if (pos > 0) {
1789 c_write("\b \b", 3);
1790 pos--;
1791 }
1792 break;
1793 case 21: case 27:
1794 while (pos > 0) {
1795 c_write("\b \b", 3);
1796 pos--;
1797 }
1798 break;
1799 case 3: case 4:
1800 random_save_seed();
1801 exit(0);
1802 break;
1803 default:
1804 if (((c >= ' ' && c <= '~') ||
1805 ((unsigned char)c >= 160)) && pos < 40) {
1806 username[pos++] = c;
1807 c_write(&c, 1);
1808 }
1809 break;
1810 }
1811 }
1812 c_write("\r\n", 2);
1813 username[strcspn(username, "\n\r")] = '\0';
1814 } else {
1815 char stuff[200];
1816 strncpy(username, cfg.username, 99);
1817 username[99] = '\0';
1818 if (!IS_SCP) {
1819 sprintf(stuff, "Using username \"%s\".\r\n", username);
1820 c_write(stuff, strlen(stuff));
1821 }
1822 }
1823
1824 if (IS_SCP) {
1825 char prompt[200];
1826 sprintf(prompt, "%s@%s's password: ", cfg.username, savedhost);
1827 if (!ssh_get_password(prompt, password, sizeof(password))) {
1828 /*
1829 * get_password failed to get a password (for
1830 * example because one was supplied on the command
1831 * line which has already failed to work).
1832 * Terminate.
1833 */
1834 logevent("No more passwords to try");
1835 ssh_state = SSH_STATE_CLOSED;
1836 crReturnV;
1837 }
1838 } else {
1839 c_write("password: ", 10);
1840
1841 pos = 0;
1842 while (pos >= 0) {
1843 crWaitUntilV(!ispkt);
1844 while (inlen--) switch (c = *in++) {
1845 case 10: case 13:
1846 password[pos] = 0;
1847 pos = -1;
1848 break;
1849 case 8: case 127:
1850 if (pos > 0)
1851 pos--;
1852 break;
1853 case 21: case 27:
1854 pos = 0;
1855 break;
1856 case 3: case 4:
1857 random_save_seed();
1858 exit(0);
1859 break;
1860 default:
1861 if (((c >= ' ' && c <= '~') ||
1862 ((unsigned char)c >= 160)) && pos < 40)
1863 password[pos++] = c;
1864 break;
1865 }
1866 }
1867 c_write("\r\n", 2);
1868 }
1869
1870 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
1871 ssh2_pkt_addstring(username);
1872 ssh2_pkt_addstring("ssh-connection"); /* service requested */
1873 ssh2_pkt_addstring("password");
1874 ssh2_pkt_addbool(FALSE);
1875 ssh2_pkt_addstring(password);
1876 ssh2_pkt_send();
1877
1878 crWaitUntilV(ispkt);
1879 if (pktin.type != SSH2_MSG_USERAUTH_SUCCESS) {
1880 c_write("Access denied\r\n", 15);
1881 logevent("Authentication refused");
1882 } else
1883 break;
1884 }
1885
1886 /*
1887 * Now we're authenticated for the connection protocol. The
1888 * connection protocol will automatically have started at this
1889 * point; there's no need to send SERVICE_REQUEST.
1890 */
1891
1892 /*
1893 * So now create a channel with a session in it.
1894 */
1895 ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN);
1896 ssh2_pkt_addstring("session");
1897 ssh2_pkt_adduint32(100); /* as good as any */
1898 ssh2_pkt_adduint32(0xFFFFFFFFUL); /* very big window which we ignore */
1899 ssh2_pkt_adduint32(0xFFFFFFFFUL); /* very big max pkt size */
1900 ssh2_pkt_send();
1901 crWaitUntilV(ispkt);
1902 if (pktin.type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
1903 fatalbox("Server refused to open a session");
1904 /* FIXME: error data comes back in FAILURE packet */
1905 }
1906 if (ssh2_pkt_getuint32() != 100) {
1907 fatalbox("Server's channel confirmation cited wrong channel");
1908 }
1909 their_channel = ssh2_pkt_getuint32();
1910 remote_winsize = ssh2_pkt_getuint32();
1911 remote_maxpkt = ssh2_pkt_getuint32();
1912 logevent("Opened channel for session");
1913
1914 /*
1915 * Now allocate a pty for the session.
1916 */
1917 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
1918 ssh2_pkt_adduint32(their_channel); /* recipient channel */
1919 ssh2_pkt_addstring("pty-req");
1920 ssh2_pkt_addbool(1); /* want reply */
1921 ssh2_pkt_addstring(cfg.termtype);
1922 ssh2_pkt_adduint32(cols);
1923 ssh2_pkt_adduint32(rows);
1924 ssh2_pkt_adduint32(0); /* pixel width */
1925 ssh2_pkt_adduint32(0); /* pixel height */
1926 ssh2_pkt_addstring_start();
1927 ssh2_pkt_addstring_data("\0", 1); /* TTY_OP_END, no special options */
1928 ssh2_pkt_send();
1929
1930 do { /* FIXME: pay attention to these */
1931 crWaitUntilV(ispkt);
1932 } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1933
1934 if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
1935 if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
1936 fatalbox("Server got confused by pty request");
1937 }
1938 c_write("Server refused to allocate pty\r\n", 32);
1939 } else {
1940 logevent("Allocated pty");
1941 }
1942
1943 /*
1944 * Start a shell.
1945 */
1946 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
1947 ssh2_pkt_adduint32(their_channel); /* recipient channel */
1948 ssh2_pkt_addstring("shell");
1949 ssh2_pkt_addbool(1); /* want reply */
1950 ssh2_pkt_send();
1951 do { /* FIXME: pay attention to these */
1952 crWaitUntilV(ispkt);
1953 } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1954 if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
1955 if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
1956 fatalbox("Server got confused by shell request");
1957 }
1958 fatalbox("Server refused to start a shell");
1959 } else {
1960 logevent("Started a shell");
1961 }
1962
1963 /*
1964 * Transfer data!
1965 */
1966 while (1) {
e5574168 1967 crReturnV;
7cca0d81 1968 if (ispkt) {
1969 if (pktin.type == SSH2_MSG_CHANNEL_DATA ||
1970 pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA) {
1971 char *data;
1972 int length;
1973 if (ssh2_pkt_getuint32() != 100)
1974 continue; /* wrong channel */
1975 if (pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
1976 ssh2_pkt_getuint32() != SSH2_EXTENDED_DATA_STDERR)
1977 continue; /* extended but not stderr */
1978 ssh2_pkt_getstring(&data, &length);
1979 if (data)
1980 c_write(data, length);
1981 } else if (pktin.type == SSH2_MSG_DISCONNECT) {
1982 ssh_state = SSH_STATE_CLOSED;
1983 logevent("Received disconnect request");
1984 } else if (pktin.type == SSH2_MSG_CHANNEL_REQUEST) {
1985 continue; /* exit status et al; ignore (FIXME?) */
1986 } else if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
1987 continue; /* ignore for now (FIXME!) */
1988 } else {
1989 fatalbox("Strange packet received: type %d", pktin.type);
1990 }
1991 } else {
1992 /* FIXME: for now, ignore window size */
1993 ssh2_pkt_init(SSH2_MSG_CHANNEL_DATA);
1994 ssh2_pkt_adduint32(their_channel);
1995 ssh2_pkt_addstring_start();
1996 ssh2_pkt_addstring_data(in, inlen);
1997 ssh2_pkt_send();
1998 }
e5574168 1999 }
2000
2001 crFinishV;
2002}
2003
2004/*
7cca0d81 2005 * Handle the top-level SSH2 protocol.
2006 */
2007static void ssh2_protocol(unsigned char *in, int inlen, int ispkt)
2008{
2009 if (do_ssh2_transport(in, inlen, ispkt) == 0)
2010 return;
2011 do_ssh2_authconn(in, inlen, ispkt);
2012}
2013
2014/*
374330e2 2015 * Called to set up the connection. Will arrange for WM_NETEVENT
2016 * messages to be passed to the specified window, whose window
2017 * procedure should then call telnet_msg().
2018 *
2019 * Returns an error message, or NULL on success.
374330e2 2020 */
2021static char *ssh_init (HWND hwnd, char *host, int port, char **realhost) {
fb09bf1c 2022 char *p;
8f203108 2023
2024#ifdef MSCRYPTOAPI
2025 if(crypto_startup() == 0)
2026 return "Microsoft high encryption pack not installed!";
2027#endif
374330e2 2028
fb09bf1c 2029 p = connect_to_host(host, port, realhost);
2030 if (p != NULL)
2031 return p;
374330e2 2032
2033 if (!do_ssh_init())
2034 return "Protocol initialisation error";
2035
2036 if (WSAAsyncSelect (s, hwnd, WM_NETEVENT, FD_READ | FD_CLOSE) == SOCKET_ERROR)
2037 switch (WSAGetLastError()) {
2038 case WSAENETDOWN: return "Network is down";
2039 default: return "WSAAsyncSelect(): unknown error";
2040 }
2041
2042 return NULL;
2043}
2044
2045/*
2046 * Process a WM_NETEVENT message. Will return 0 if the connection
2047 * has closed, or <0 for a socket error.
2048 */
2049static int ssh_msg (WPARAM wParam, LPARAM lParam) {
2050 int ret;
2051 char buf[256];
2052
8ce72d2c 2053 /*
2054 * Because reading less than the whole of the available pending
2055 * data can generate an FD_READ event, we need to allow for the
2056 * possibility that FD_READ may arrive with FD_CLOSE already in
2057 * the queue; so it's possible that we can get here even with s
2058 * invalid. If so, we return 1 and don't worry about it.
2059 */
2060 if (s == INVALID_SOCKET)
2061 return 1;
374330e2 2062
2063 if (WSAGETSELECTERROR(lParam) != 0)
2064 return -WSAGETSELECTERROR(lParam);
2065
2066 switch (WSAGETSELECTEVENT(lParam)) {
2067 case FD_READ:
8ce72d2c 2068 case FD_CLOSE:
374330e2 2069 ret = recv(s, buf, sizeof(buf), 0);
2070 if (ret < 0 && WSAGetLastError() == WSAEWOULDBLOCK)
2071 return 1;
2072 if (ret < 0) /* any _other_ error */
2073 return -10000-WSAGetLastError();
2074 if (ret == 0) {
2075 s = INVALID_SOCKET;
8ce72d2c 2076 return 0;
374330e2 2077 }
2078 ssh_gotdata (buf, ret);
85ee8208 2079 if (ssh_state == SSH_STATE_CLOSED) {
2080 closesocket(s);
2081 s = INVALID_SOCKET;
2082 return 0;
2083 }
374330e2 2084 return 1;
374330e2 2085 }
2086 return 1; /* shouldn't happen, but WTF */
2087}
2088
2089/*
2090 * Called to send data down the Telnet connection.
2091 */
2092static void ssh_send (char *buf, int len) {
2093 if (s == INVALID_SOCKET)
2094 return;
2095
2096 ssh_protocol(buf, len, 0);
2097}
2098
2099/*
2100 * Called to set the size of the window from Telnet's POV.
2101 */
2102static void ssh_size(void) {
2103 switch (ssh_state) {
2104 case SSH_STATE_BEFORE_SIZE:
21248260 2105 case SSH_STATE_CLOSED:
374330e2 2106 break; /* do nothing */
2107 case SSH_STATE_INTERMED:
2108 size_needed = TRUE; /* buffer for later */
2109 break;
2110 case SSH_STATE_SESSION:
fef97f43 2111 if (!cfg.nopty) {
e5574168 2112 send_packet(SSH1_CMSG_WINDOW_SIZE,
fb09bf1c 2113 PKT_INT, rows, PKT_INT, cols,
2114 PKT_INT, 0, PKT_INT, 0, PKT_END);
fef97f43 2115 }
374330e2 2116 }
2117}
2118
2119/*
2120 * (Send Telnet special codes)
2121 */
2122static void ssh_special (Telnet_Special code) {
2123 /* do nothing */
2124}
2125
fb09bf1c 2126
2127/*
2128 * Read and decrypt one incoming SSH packet.
2129 * (only used by pSCP)
2130 */
2131static void get_packet(void)
2132{
2133 unsigned char buf[4096], *p;
2134 long to_read;
2135 int len;
2136
2137 assert(IS_SCP);
2138
2139 p = NULL;
2140 len = 0;
2141
2142 while ((to_read = s_rdpkt(&p, &len)) > 0) {
2143 if (to_read > sizeof(buf)) to_read = sizeof(buf);
2144 len = s_read(buf, to_read);
2145 if (len != to_read) {
2146 closesocket(s);
2147 s = INVALID_SOCKET;
2148 return;
2149 }
2150 p = buf;
2151 }
2152
2153 assert(len == 0);
2154}
2155
2156/*
2157 * Receive a block of data over the SSH link. Block until
2158 * all data is available. Return nr of bytes read (0 if lost connection).
2159 * (only used by pSCP)
2160 */
2161int ssh_scp_recv(unsigned char *buf, int len)
2162{
2163 static int pending_input_len = 0;
2164 static unsigned char *pending_input_ptr;
2165 int to_read = len;
2166
2167 assert(IS_SCP);
2168
2169 if (pending_input_len >= to_read) {
2170 memcpy(buf, pending_input_ptr, to_read);
2171 pending_input_ptr += to_read;
2172 pending_input_len -= to_read;
2173 return len;
2174 }
2175
2176 if (pending_input_len > 0) {
2177 memcpy(buf, pending_input_ptr, pending_input_len);
2178 buf += pending_input_len;
2179 to_read -= pending_input_len;
2180 pending_input_len = 0;
2181 }
2182
2183 if (s == INVALID_SOCKET)
2184 return 0;
2185 while (to_read > 0) {
2186 get_packet();
2187 if (s == INVALID_SOCKET)
2188 return 0;
e5574168 2189 if (pktin.type == SSH1_SMSG_STDOUT_DATA) {
fb09bf1c 2190 int plen = GET_32BIT(pktin.body);
2191 if (plen <= to_read) {
2192 memcpy(buf, pktin.body + 4, plen);
2193 buf += plen;
2194 to_read -= plen;
2195 } else {
2196 memcpy(buf, pktin.body + 4, to_read);
2197 pending_input_len = plen - to_read;
2198 pending_input_ptr = pktin.body + 4 + to_read;
2199 to_read = 0;
2200 }
e5574168 2201 } else if (pktin.type == SSH1_SMSG_STDERR_DATA) {
fb09bf1c 2202 int plen = GET_32BIT(pktin.body);
2203 fwrite(pktin.body + 4, plen, 1, stderr);
e5574168 2204 } else if (pktin.type == SSH1_MSG_DISCONNECT) {
fb09bf1c 2205 logevent("Received disconnect request");
e5574168 2206 } else if (pktin.type == SSH1_SMSG_SUCCESS ||
2207 pktin.type == SSH1_SMSG_FAILURE) {
fb09bf1c 2208 /* ignore */
e5574168 2209 } else if (pktin.type == SSH1_SMSG_EXIT_STATUS) {
fb09bf1c 2210 char logbuf[100];
2211 sprintf(logbuf, "Remote exit status: %d", GET_32BIT(pktin.body));
2212 logevent(logbuf);
e5574168 2213 send_packet(SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
fb09bf1c 2214 logevent("Closing connection");
2215 closesocket(s);
2216 s = INVALID_SOCKET;
2217 } else {
2218 fatalbox("Strange packet received: type %d", pktin.type);
2219 }
2220 }
2221
2222 return len;
2223}
2224
2225/*
2226 * Send a block of data over the SSH link.
2227 * Block until all data is sent.
2228 * (only used by pSCP)
2229 */
2230void ssh_scp_send(unsigned char *buf, int len)
2231{
2232 assert(IS_SCP);
2233 if (s == INVALID_SOCKET)
2234 return;
e5574168 2235 send_packet(SSH1_CMSG_STDIN_DATA,
fb09bf1c 2236 PKT_INT, len, PKT_DATA, buf, len, PKT_END);
2237}
2238
2239/*
2240 * Send an EOF notification to the server.
2241 * (only used by pSCP)
2242 */
2243void ssh_scp_send_eof(void)
2244{
2245 assert(IS_SCP);
2246 if (s == INVALID_SOCKET)
2247 return;
e5574168 2248 send_packet(SSH1_CMSG_EOF, PKT_END);
fb09bf1c 2249}
2250
2251/*
2252 * Set up the connection, login on the remote host and
2253 * start execution of a command.
2254 * Returns an error message, or NULL on success.
2255 * (only used by pSCP)
2256 */
2257char *ssh_scp_init(char *host, int port, char *cmd, char **realhost)
2258{
2259 char buf[160], *p;
2260
2261 assert(IS_SCP);
2262
2263#ifdef MSCRYPTOAPI
2264 if (crypto_startup() == 0)
2265 return "Microsoft high encryption pack not installed!";
2266#endif
2267
2268 p = connect_to_host(host, port, realhost);
2269 if (p != NULL)
2270 return p;
2271
2272 random_init();
2273
2274 if (!do_ssh_init())
2275 return "Protocol initialisation error";
2276
2277 /* Exchange keys and login */
2278 do {
2279 get_packet();
2280 if (s == INVALID_SOCKET)
2281 return "Connection closed by remote host";
e5574168 2282 } while (!do_ssh1_login(NULL, 0, 1));
85ee8208 2283
2284 if (ssh_state == SSH_STATE_CLOSED) {
2285 closesocket(s);
2286 s = INVALID_SOCKET;
2287 return "Session initialisation error";
2288 }
fb09bf1c 2289
2290 /* Execute command */
2291 sprintf(buf, "Sending command: %.100s", cmd);
2292 logevent(buf);
e5574168 2293 send_packet(SSH1_CMSG_EXEC_CMD, PKT_STR, cmd, PKT_END);
fb09bf1c 2294
2295 return NULL;
2296}
2297
2298
374330e2 2299Backend ssh_backend = {
2300 ssh_init,
2301 ssh_msg,
2302 ssh_send,
2303 ssh_size,
2304 ssh_special
2305};
Local modifications for Simon Tatham's `PuTTY' SSH client and terminal emulator