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[u/mdw/putty] / ssh.c
1 #include <stdio.h>
2 #include <stdlib.h>
3 #include <stdarg.h>
4 #include <assert.h>
5
6 #include "putty.h"
7 #include "tree234.h"
8 #include "ssh.h"
9
10 #ifndef FALSE
11 #define FALSE 0
12 #endif
13 #ifndef TRUE
14 #define TRUE 1
15 #endif
16
17 #define SSH1_MSG_DISCONNECT 1 /* 0x1 */
18 #define SSH1_SMSG_PUBLIC_KEY 2 /* 0x2 */
19 #define SSH1_CMSG_SESSION_KEY 3 /* 0x3 */
20 #define SSH1_CMSG_USER 4 /* 0x4 */
21 #define SSH1_CMSG_AUTH_RSA 6 /* 0x6 */
22 #define SSH1_SMSG_AUTH_RSA_CHALLENGE 7 /* 0x7 */
23 #define SSH1_CMSG_AUTH_RSA_RESPONSE 8 /* 0x8 */
24 #define SSH1_CMSG_AUTH_PASSWORD 9 /* 0x9 */
25 #define SSH1_CMSG_REQUEST_PTY 10 /* 0xa */
26 #define SSH1_CMSG_WINDOW_SIZE 11 /* 0xb */
27 #define SSH1_CMSG_EXEC_SHELL 12 /* 0xc */
28 #define SSH1_CMSG_EXEC_CMD 13 /* 0xd */
29 #define SSH1_SMSG_SUCCESS 14 /* 0xe */
30 #define SSH1_SMSG_FAILURE 15 /* 0xf */
31 #define SSH1_CMSG_STDIN_DATA 16 /* 0x10 */
32 #define SSH1_SMSG_STDOUT_DATA 17 /* 0x11 */
33 #define SSH1_SMSG_STDERR_DATA 18 /* 0x12 */
34 #define SSH1_CMSG_EOF 19 /* 0x13 */
35 #define SSH1_SMSG_EXIT_STATUS 20 /* 0x14 */
36 #define SSH1_MSG_CHANNEL_OPEN_CONFIRMATION 21 /* 0x15 */
37 #define SSH1_MSG_CHANNEL_OPEN_FAILURE 22 /* 0x16 */
38 #define SSH1_MSG_CHANNEL_DATA 23 /* 0x17 */
39 #define SSH1_MSG_CHANNEL_CLOSE 24 /* 0x18 */
40 #define SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION 25 /* 0x19 */
41 #define SSH1_SMSG_X11_OPEN 27 /* 0x1b */
42 #define SSH1_CMSG_PORT_FORWARD_REQUEST 28 /* 0x1c */
43 #define SSH1_MSG_PORT_OPEN 29 /* 0x1d */
44 #define SSH1_CMSG_AGENT_REQUEST_FORWARDING 30 /* 0x1e */
45 #define SSH1_SMSG_AGENT_OPEN 31 /* 0x1f */
46 #define SSH1_MSG_IGNORE 32 /* 0x20 */
47 #define SSH1_CMSG_EXIT_CONFIRMATION 33 /* 0x21 */
48 #define SSH1_CMSG_X11_REQUEST_FORWARDING 34 /* 0x22 */
49 #define SSH1_CMSG_AUTH_RHOSTS_RSA 35 /* 0x23 */
50 #define SSH1_MSG_DEBUG 36 /* 0x24 */
51 #define SSH1_CMSG_REQUEST_COMPRESSION 37 /* 0x25 */
52 #define SSH1_CMSG_AUTH_TIS 39 /* 0x27 */
53 #define SSH1_SMSG_AUTH_TIS_CHALLENGE 40 /* 0x28 */
54 #define SSH1_CMSG_AUTH_TIS_RESPONSE 41 /* 0x29 */
55 #define SSH1_CMSG_AUTH_CCARD 70 /* 0x46 */
56 #define SSH1_SMSG_AUTH_CCARD_CHALLENGE 71 /* 0x47 */
57 #define SSH1_CMSG_AUTH_CCARD_RESPONSE 72 /* 0x48 */
58
59 #define SSH1_AUTH_TIS 5 /* 0x5 */
60 #define SSH1_AUTH_CCARD 16 /* 0x10 */
61
62 #define SSH1_PROTOFLAG_SCREEN_NUMBER 1 /* 0x1 */
63 /* Mask for protoflags we will echo back to server if seen */
64 #define SSH1_PROTOFLAGS_SUPPORTED 0 /* 0x1 */
65
66 #define SSH2_MSG_DISCONNECT 1 /* 0x1 */
67 #define SSH2_MSG_IGNORE 2 /* 0x2 */
68 #define SSH2_MSG_UNIMPLEMENTED 3 /* 0x3 */
69 #define SSH2_MSG_DEBUG 4 /* 0x4 */
70 #define SSH2_MSG_SERVICE_REQUEST 5 /* 0x5 */
71 #define SSH2_MSG_SERVICE_ACCEPT 6 /* 0x6 */
72 #define SSH2_MSG_KEXINIT 20 /* 0x14 */
73 #define SSH2_MSG_NEWKEYS 21 /* 0x15 */
74 #define SSH2_MSG_KEXDH_INIT 30 /* 0x1e */
75 #define SSH2_MSG_KEXDH_REPLY 31 /* 0x1f */
76 #define SSH2_MSG_KEX_DH_GEX_REQUEST 30 /* 0x1e */
77 #define SSH2_MSG_KEX_DH_GEX_GROUP 31 /* 0x1f */
78 #define SSH2_MSG_KEX_DH_GEX_INIT 32 /* 0x20 */
79 #define SSH2_MSG_KEX_DH_GEX_REPLY 33 /* 0x21 */
80 #define SSH2_MSG_USERAUTH_REQUEST 50 /* 0x32 */
81 #define SSH2_MSG_USERAUTH_FAILURE 51 /* 0x33 */
82 #define SSH2_MSG_USERAUTH_SUCCESS 52 /* 0x34 */
83 #define SSH2_MSG_USERAUTH_BANNER 53 /* 0x35 */
84 #define SSH2_MSG_USERAUTH_PK_OK 60 /* 0x3c */
85 #define SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ 60 /* 0x3c */
86 #define SSH2_MSG_USERAUTH_INFO_REQUEST 60 /* 0x3c */
87 #define SSH2_MSG_USERAUTH_INFO_RESPONSE 61 /* 0x3d */
88 #define SSH2_MSG_GLOBAL_REQUEST 80 /* 0x50 */
89 #define SSH2_MSG_REQUEST_SUCCESS 81 /* 0x51 */
90 #define SSH2_MSG_REQUEST_FAILURE 82 /* 0x52 */
91 #define SSH2_MSG_CHANNEL_OPEN 90 /* 0x5a */
92 #define SSH2_MSG_CHANNEL_OPEN_CONFIRMATION 91 /* 0x5b */
93 #define SSH2_MSG_CHANNEL_OPEN_FAILURE 92 /* 0x5c */
94 #define SSH2_MSG_CHANNEL_WINDOW_ADJUST 93 /* 0x5d */
95 #define SSH2_MSG_CHANNEL_DATA 94 /* 0x5e */
96 #define SSH2_MSG_CHANNEL_EXTENDED_DATA 95 /* 0x5f */
97 #define SSH2_MSG_CHANNEL_EOF 96 /* 0x60 */
98 #define SSH2_MSG_CHANNEL_CLOSE 97 /* 0x61 */
99 #define SSH2_MSG_CHANNEL_REQUEST 98 /* 0x62 */
100 #define SSH2_MSG_CHANNEL_SUCCESS 99 /* 0x63 */
101 #define SSH2_MSG_CHANNEL_FAILURE 100 /* 0x64 */
102
103 /*
104 * Packet type contexts, so that ssh2_pkt_type can correctly decode
105 * the ambiguous type numbers back into the correct type strings.
106 */
107 #define SSH2_PKTCTX_DHGROUP1 0x0001
108 #define SSH2_PKTCTX_DHGEX 0x0002
109 #define SSH2_PKTCTX_PUBLICKEY 0x0010
110 #define SSH2_PKTCTX_PASSWORD 0x0020
111 #define SSH2_PKTCTX_KBDINTER 0x0040
112 #define SSH2_PKTCTX_AUTH_MASK 0x00F0
113
114 #define SSH2_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT 1 /* 0x1 */
115 #define SSH2_DISCONNECT_PROTOCOL_ERROR 2 /* 0x2 */
116 #define SSH2_DISCONNECT_KEY_EXCHANGE_FAILED 3 /* 0x3 */
117 #define SSH2_DISCONNECT_HOST_AUTHENTICATION_FAILED 4 /* 0x4 */
118 #define SSH2_DISCONNECT_MAC_ERROR 5 /* 0x5 */
119 #define SSH2_DISCONNECT_COMPRESSION_ERROR 6 /* 0x6 */
120 #define SSH2_DISCONNECT_SERVICE_NOT_AVAILABLE 7 /* 0x7 */
121 #define SSH2_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED 8 /* 0x8 */
122 #define SSH2_DISCONNECT_HOST_KEY_NOT_VERIFIABLE 9 /* 0x9 */
123 #define SSH2_DISCONNECT_CONNECTION_LOST 10 /* 0xa */
124 #define SSH2_DISCONNECT_BY_APPLICATION 11 /* 0xb */
125 #define SSH2_DISCONNECT_TOO_MANY_CONNECTIONS 12 /* 0xc */
126 #define SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER 13 /* 0xd */
127 #define SSH2_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE 14 /* 0xe */
128 #define SSH2_DISCONNECT_ILLEGAL_USER_NAME 15 /* 0xf */
129
130 static const char *const ssh2_disconnect_reasons[] = {
131 NULL,
132 "SSH_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT",
133 "SSH_DISCONNECT_PROTOCOL_ERROR",
134 "SSH_DISCONNECT_KEY_EXCHANGE_FAILED",
135 "SSH_DISCONNECT_HOST_AUTHENTICATION_FAILED",
136 "SSH_DISCONNECT_MAC_ERROR",
137 "SSH_DISCONNECT_COMPRESSION_ERROR",
138 "SSH_DISCONNECT_SERVICE_NOT_AVAILABLE",
139 "SSH_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED",
140 "SSH_DISCONNECT_HOST_KEY_NOT_VERIFIABLE",
141 "SSH_DISCONNECT_CONNECTION_LOST",
142 "SSH_DISCONNECT_BY_APPLICATION",
143 "SSH_DISCONNECT_TOO_MANY_CONNECTIONS",
144 "SSH_DISCONNECT_AUTH_CANCELLED_BY_USER",
145 "SSH_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE",
146 "SSH_DISCONNECT_ILLEGAL_USER_NAME",
147 };
148
149 #define SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED 1 /* 0x1 */
150 #define SSH2_OPEN_CONNECT_FAILED 2 /* 0x2 */
151 #define SSH2_OPEN_UNKNOWN_CHANNEL_TYPE 3 /* 0x3 */
152 #define SSH2_OPEN_RESOURCE_SHORTAGE 4 /* 0x4 */
153
154 #define SSH2_EXTENDED_DATA_STDERR 1 /* 0x1 */
155
156 /*
157 * Various remote-bug flags.
158 */
159 #define BUG_CHOKES_ON_SSH1_IGNORE 1
160 #define BUG_SSH2_HMAC 2
161 #define BUG_NEEDS_SSH1_PLAIN_PASSWORD 4
162 #define BUG_CHOKES_ON_RSA 8
163 #define BUG_SSH2_RSA_PADDING 16
164 #define BUG_SSH2_DERIVEKEY 32
165 #define BUG_SSH2_DH_GEX 64
166 #define BUG_SSH2_PK_SESSIONID 128
167
168 #define translate(x) if (type == x) return #x
169 #define translatec(x,ctx) if (type == x && (pkt_ctx & ctx)) return #x
170 static char *ssh1_pkt_type(int type)
171 {
172 translate(SSH1_MSG_DISCONNECT);
173 translate(SSH1_SMSG_PUBLIC_KEY);
174 translate(SSH1_CMSG_SESSION_KEY);
175 translate(SSH1_CMSG_USER);
176 translate(SSH1_CMSG_AUTH_RSA);
177 translate(SSH1_SMSG_AUTH_RSA_CHALLENGE);
178 translate(SSH1_CMSG_AUTH_RSA_RESPONSE);
179 translate(SSH1_CMSG_AUTH_PASSWORD);
180 translate(SSH1_CMSG_REQUEST_PTY);
181 translate(SSH1_CMSG_WINDOW_SIZE);
182 translate(SSH1_CMSG_EXEC_SHELL);
183 translate(SSH1_CMSG_EXEC_CMD);
184 translate(SSH1_SMSG_SUCCESS);
185 translate(SSH1_SMSG_FAILURE);
186 translate(SSH1_CMSG_STDIN_DATA);
187 translate(SSH1_SMSG_STDOUT_DATA);
188 translate(SSH1_SMSG_STDERR_DATA);
189 translate(SSH1_CMSG_EOF);
190 translate(SSH1_SMSG_EXIT_STATUS);
191 translate(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION);
192 translate(SSH1_MSG_CHANNEL_OPEN_FAILURE);
193 translate(SSH1_MSG_CHANNEL_DATA);
194 translate(SSH1_MSG_CHANNEL_CLOSE);
195 translate(SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION);
196 translate(SSH1_SMSG_X11_OPEN);
197 translate(SSH1_CMSG_PORT_FORWARD_REQUEST);
198 translate(SSH1_MSG_PORT_OPEN);
199 translate(SSH1_CMSG_AGENT_REQUEST_FORWARDING);
200 translate(SSH1_SMSG_AGENT_OPEN);
201 translate(SSH1_MSG_IGNORE);
202 translate(SSH1_CMSG_EXIT_CONFIRMATION);
203 translate(SSH1_CMSG_X11_REQUEST_FORWARDING);
204 translate(SSH1_CMSG_AUTH_RHOSTS_RSA);
205 translate(SSH1_MSG_DEBUG);
206 translate(SSH1_CMSG_REQUEST_COMPRESSION);
207 translate(SSH1_CMSG_AUTH_TIS);
208 translate(SSH1_SMSG_AUTH_TIS_CHALLENGE);
209 translate(SSH1_CMSG_AUTH_TIS_RESPONSE);
210 translate(SSH1_CMSG_AUTH_CCARD);
211 translate(SSH1_SMSG_AUTH_CCARD_CHALLENGE);
212 translate(SSH1_CMSG_AUTH_CCARD_RESPONSE);
213 return "unknown";
214 }
215 static char *ssh2_pkt_type(int pkt_ctx, int type)
216 {
217 translate(SSH2_MSG_DISCONNECT);
218 translate(SSH2_MSG_IGNORE);
219 translate(SSH2_MSG_UNIMPLEMENTED);
220 translate(SSH2_MSG_DEBUG);
221 translate(SSH2_MSG_SERVICE_REQUEST);
222 translate(SSH2_MSG_SERVICE_ACCEPT);
223 translate(SSH2_MSG_KEXINIT);
224 translate(SSH2_MSG_NEWKEYS);
225 translatec(SSH2_MSG_KEXDH_INIT, SSH2_PKTCTX_DHGROUP1);
226 translatec(SSH2_MSG_KEXDH_REPLY, SSH2_PKTCTX_DHGROUP1);
227 translatec(SSH2_MSG_KEX_DH_GEX_REQUEST, SSH2_PKTCTX_DHGEX);
228 translatec(SSH2_MSG_KEX_DH_GEX_GROUP, SSH2_PKTCTX_DHGEX);
229 translatec(SSH2_MSG_KEX_DH_GEX_INIT, SSH2_PKTCTX_DHGEX);
230 translatec(SSH2_MSG_KEX_DH_GEX_REPLY, SSH2_PKTCTX_DHGEX);
231 translate(SSH2_MSG_USERAUTH_REQUEST);
232 translate(SSH2_MSG_USERAUTH_FAILURE);
233 translate(SSH2_MSG_USERAUTH_SUCCESS);
234 translate(SSH2_MSG_USERAUTH_BANNER);
235 translatec(SSH2_MSG_USERAUTH_PK_OK, SSH2_PKTCTX_PUBLICKEY);
236 translatec(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, SSH2_PKTCTX_PASSWORD);
237 translatec(SSH2_MSG_USERAUTH_INFO_REQUEST, SSH2_PKTCTX_KBDINTER);
238 translatec(SSH2_MSG_USERAUTH_INFO_RESPONSE, SSH2_PKTCTX_KBDINTER);
239 translate(SSH2_MSG_GLOBAL_REQUEST);
240 translate(SSH2_MSG_REQUEST_SUCCESS);
241 translate(SSH2_MSG_REQUEST_FAILURE);
242 translate(SSH2_MSG_CHANNEL_OPEN);
243 translate(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
244 translate(SSH2_MSG_CHANNEL_OPEN_FAILURE);
245 translate(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
246 translate(SSH2_MSG_CHANNEL_DATA);
247 translate(SSH2_MSG_CHANNEL_EXTENDED_DATA);
248 translate(SSH2_MSG_CHANNEL_EOF);
249 translate(SSH2_MSG_CHANNEL_CLOSE);
250 translate(SSH2_MSG_CHANNEL_REQUEST);
251 translate(SSH2_MSG_CHANNEL_SUCCESS);
252 translate(SSH2_MSG_CHANNEL_FAILURE);
253 return "unknown";
254 }
255 #undef translate
256 #undef translatec
257
258 #define GET_32BIT(cp) \
259 (((unsigned long)(unsigned char)(cp)[0] << 24) | \
260 ((unsigned long)(unsigned char)(cp)[1] << 16) | \
261 ((unsigned long)(unsigned char)(cp)[2] << 8) | \
262 ((unsigned long)(unsigned char)(cp)[3]))
263
264 #define PUT_32BIT(cp, value) { \
265 (cp)[0] = (unsigned char)((value) >> 24); \
266 (cp)[1] = (unsigned char)((value) >> 16); \
267 (cp)[2] = (unsigned char)((value) >> 8); \
268 (cp)[3] = (unsigned char)(value); }
269
270 enum { PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR, PKT_BIGNUM };
271
272 /*
273 * Coroutine mechanics for the sillier bits of the code. If these
274 * macros look impenetrable to you, you might find it helpful to
275 * read
276 *
277 * http://www.chiark.greenend.org.uk/~sgtatham/coroutines.html
278 *
279 * which explains the theory behind these macros.
280 *
281 * In particular, if you are getting `case expression not constant'
282 * errors when building with MS Visual Studio, this is because MS's
283 * Edit and Continue debugging feature causes their compiler to
284 * violate ANSI C. To disable Edit and Continue debugging:
285 *
286 * - right-click ssh.c in the FileView
287 * - click Settings
288 * - select the C/C++ tab and the General category
289 * - under `Debug info:', select anything _other_ than `Program
290 * Database for Edit and Continue'.
291 */
292 #define crBegin(v) { int *crLine = &v; switch(v) { case 0:;
293 #define crState(t) \
294 struct t *s; \
295 if (!ssh->t) ssh->t = snew(struct t); \
296 s = ssh->t;
297 #define crFinish(z) } *crLine = 0; return (z); }
298 #define crFinishV } *crLine = 0; return; }
299 #define crReturn(z) \
300 do {\
301 *crLine =__LINE__; return (z); case __LINE__:;\
302 } while (0)
303 #define crReturnV \
304 do {\
305 *crLine=__LINE__; return; case __LINE__:;\
306 } while (0)
307 #define crStop(z) do{ *crLine = 0; return (z); }while(0)
308 #define crStopV do{ *crLine = 0; return; }while(0)
309 #define crWaitUntil(c) do { crReturn(0); } while (!(c))
310 #define crWaitUntilV(c) do { crReturnV; } while (!(c))
311
312 typedef struct ssh_tag *Ssh;
313
314 static void ssh2_pkt_init(Ssh, int pkt_type);
315 static void ssh2_pkt_addbool(Ssh, unsigned char value);
316 static void ssh2_pkt_adduint32(Ssh, unsigned long value);
317 static void ssh2_pkt_addstring_start(Ssh);
318 static void ssh2_pkt_addstring_str(Ssh, char *data);
319 static void ssh2_pkt_addstring_data(Ssh, char *data, int len);
320 static void ssh2_pkt_addstring(Ssh, char *data);
321 static unsigned char *ssh2_mpint_fmt(Bignum b, int *len);
322 static void ssh2_pkt_addmp(Ssh, Bignum b);
323 static int ssh2_pkt_construct(Ssh);
324 static void ssh2_pkt_send(Ssh);
325
326 /*
327 * Buffer management constants. There are several of these for
328 * various different purposes:
329 *
330 * - SSH1_BUFFER_LIMIT is the amount of backlog that must build up
331 * on a local data stream before we throttle the whole SSH
332 * connection (in SSH1 only). Throttling the whole connection is
333 * pretty drastic so we set this high in the hope it won't
334 * happen very often.
335 *
336 * - SSH_MAX_BACKLOG is the amount of backlog that must build up
337 * on the SSH connection itself before we defensively throttle
338 * _all_ local data streams. This is pretty drastic too (though
339 * thankfully unlikely in SSH2 since the window mechanism should
340 * ensure that the server never has any need to throttle its end
341 * of the connection), so we set this high as well.
342 *
343 * - OUR_V2_WINSIZE is the maximum window size we present on SSH2
344 * channels.
345 */
346
347 #define SSH1_BUFFER_LIMIT 32768
348 #define SSH_MAX_BACKLOG 32768
349 #define OUR_V2_WINSIZE 16384
350
351 const static struct ssh_kex *kex_algs[] = {
352 &ssh_diffiehellman_gex,
353 &ssh_diffiehellman
354 };
355
356 const static struct ssh_signkey *hostkey_algs[] = { &ssh_rsa, &ssh_dss };
357
358 static void *nullmac_make_context(void)
359 {
360 return NULL;
361 }
362 static void nullmac_free_context(void *handle)
363 {
364 }
365 static void nullmac_key(void *handle, unsigned char *key)
366 {
367 }
368 static void nullmac_generate(void *handle, unsigned char *blk, int len,
369 unsigned long seq)
370 {
371 }
372 static int nullmac_verify(void *handle, unsigned char *blk, int len,
373 unsigned long seq)
374 {
375 return 1;
376 }
377 const static struct ssh_mac ssh_mac_none = {
378 nullmac_make_context, nullmac_free_context, nullmac_key,
379 nullmac_generate, nullmac_verify, "none", 0
380 };
381 const static struct ssh_mac *macs[] = {
382 &ssh_sha1, &ssh_md5, &ssh_mac_none
383 };
384 const static struct ssh_mac *buggymacs[] = {
385 &ssh_sha1_buggy, &ssh_md5, &ssh_mac_none
386 };
387
388 static void *ssh_comp_none_init(void)
389 {
390 return NULL;
391 }
392 static void ssh_comp_none_cleanup(void *handle)
393 {
394 }
395 static int ssh_comp_none_block(void *handle, unsigned char *block, int len,
396 unsigned char **outblock, int *outlen)
397 {
398 return 0;
399 }
400 static int ssh_comp_none_disable(void *handle)
401 {
402 return 0;
403 }
404 const static struct ssh_compress ssh_comp_none = {
405 "none",
406 ssh_comp_none_init, ssh_comp_none_cleanup, ssh_comp_none_block,
407 ssh_comp_none_init, ssh_comp_none_cleanup, ssh_comp_none_block,
408 ssh_comp_none_disable, NULL
409 };
410 extern const struct ssh_compress ssh_zlib;
411 const static struct ssh_compress *compressions[] = {
412 &ssh_zlib, &ssh_comp_none
413 };
414
415 enum { /* channel types */
416 CHAN_MAINSESSION,
417 CHAN_X11,
418 CHAN_AGENT,
419 CHAN_SOCKDATA,
420 CHAN_SOCKDATA_DORMANT /* one the remote hasn't confirmed */
421 };
422
423 /*
424 * 2-3-4 tree storing channels.
425 */
426 struct ssh_channel {
427 Ssh ssh; /* pointer back to main context */
428 unsigned remoteid, localid;
429 int type;
430 /*
431 * In SSH1, this value contains four bits:
432 *
433 * 1 We have sent SSH1_MSG_CHANNEL_CLOSE.
434 * 2 We have sent SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION.
435 * 4 We have received SSH1_MSG_CHANNEL_CLOSE.
436 * 8 We have received SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION.
437 *
438 * A channel is completely finished with when all four bits are set.
439 */
440 int closes;
441 union {
442 struct ssh1_data_channel {
443 int throttling;
444 } v1;
445 struct ssh2_data_channel {
446 bufchain outbuffer;
447 unsigned remwindow, remmaxpkt;
448 unsigned locwindow;
449 } v2;
450 } v;
451 union {
452 struct ssh_agent_channel {
453 unsigned char *message;
454 unsigned char msglen[4];
455 int lensofar, totallen;
456 } a;
457 struct ssh_x11_channel {
458 Socket s;
459 } x11;
460 struct ssh_pfd_channel {
461 Socket s;
462 } pfd;
463 } u;
464 };
465
466 /*
467 * 2-3-4 tree storing remote->local port forwardings. SSH 1 and SSH
468 * 2 use this structure in different ways, reflecting SSH 2's
469 * altogether saner approach to port forwarding.
470 *
471 * In SSH 1, you arrange a remote forwarding by sending the server
472 * the remote port number, and the local destination host:port.
473 * When a connection comes in, the server sends you back that
474 * host:port pair, and you connect to it. This is a ready-made
475 * security hole if you're not on the ball: a malicious server
476 * could send you back _any_ host:port pair, so if you trustingly
477 * connect to the address it gives you then you've just opened the
478 * entire inside of your corporate network just by connecting
479 * through it to a dodgy SSH server. Hence, we must store a list of
480 * host:port pairs we _are_ trying to forward to, and reject a
481 * connection request from the server if it's not in the list.
482 *
483 * In SSH 2, each side of the connection minds its own business and
484 * doesn't send unnecessary information to the other. You arrange a
485 * remote forwarding by sending the server just the remote port
486 * number. When a connection comes in, the server tells you which
487 * of its ports was connected to; and _you_ have to remember what
488 * local host:port pair went with that port number.
489 *
490 * Hence: in SSH 1 this structure stores host:port pairs we intend
491 * to allow connections to, and is indexed by those host:port
492 * pairs. In SSH 2 it stores a mapping from source port to
493 * destination host:port pair, and is indexed by source port.
494 */
495 struct ssh_rportfwd {
496 unsigned sport, dport;
497 char dhost[256];
498 };
499
500 struct Packet {
501 long length;
502 int type;
503 unsigned char *data;
504 unsigned char *body;
505 long savedpos;
506 long maxlen;
507 };
508
509 static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt);
510 static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt);
511 static void ssh_size(void *handle, int width, int height);
512 static void ssh_special(void *handle, Telnet_Special);
513 static int ssh2_try_send(struct ssh_channel *c);
514 static void ssh2_add_channel_data(struct ssh_channel *c, char *buf, int len);
515 static void ssh_throttle_all(Ssh ssh, int enable, int bufsize);
516 static void ssh2_set_window(struct ssh_channel *c, unsigned newwin);
517 static int ssh_sendbuffer(void *handle);
518
519 struct rdpkt1_state_tag {
520 long len, pad, biglen, to_read;
521 unsigned long realcrc, gotcrc;
522 unsigned char *p;
523 int i;
524 int chunk;
525 };
526
527 struct rdpkt2_state_tag {
528 long len, pad, payload, packetlen, maclen;
529 int i;
530 int cipherblk;
531 unsigned long incoming_sequence;
532 };
533
534 struct ssh_tag {
535 const struct plug_function_table *fn;
536 /* the above field _must_ be first in the structure */
537
538 SHA_State exhash, exhashbase;
539
540 Socket s;
541
542 void *ldisc;
543 void *logctx;
544
545 unsigned char session_key[32];
546 int v1_compressing;
547 int v1_remote_protoflags;
548 int v1_local_protoflags;
549 int agentfwd_enabled;
550 int X11_fwd_enabled;
551 int remote_bugs;
552 const struct ssh_cipher *cipher;
553 void *v1_cipher_ctx;
554 void *crcda_ctx;
555 const struct ssh2_cipher *cscipher, *sccipher;
556 void *cs_cipher_ctx, *sc_cipher_ctx;
557 const struct ssh_mac *csmac, *scmac;
558 void *cs_mac_ctx, *sc_mac_ctx;
559 const struct ssh_compress *cscomp, *sccomp;
560 void *cs_comp_ctx, *sc_comp_ctx;
561 const struct ssh_kex *kex;
562 const struct ssh_signkey *hostkey;
563 unsigned char v2_session_id[20];
564 void *kex_ctx;
565
566 char *savedhost;
567 int savedport;
568 int send_ok;
569 int echoing, editing;
570
571 void *frontend;
572
573 int term_width, term_height;
574
575 tree234 *channels; /* indexed by local id */
576 struct ssh_channel *mainchan; /* primary session channel */
577 int exitcode;
578
579 tree234 *rportfwds;
580
581 enum {
582 SSH_STATE_PREPACKET,
583 SSH_STATE_BEFORE_SIZE,
584 SSH_STATE_INTERMED,
585 SSH_STATE_SESSION,
586 SSH_STATE_CLOSED
587 } state;
588
589 int size_needed, eof_needed;
590
591 struct Packet pktin;
592 struct Packet pktout;
593 unsigned char *deferred_send_data;
594 int deferred_len, deferred_size;
595
596 /*
597 * Gross hack: pscp will try to start SFTP but fall back to
598 * scp1 if that fails. This variable is the means by which
599 * scp.c can reach into the SSH code and find out which one it
600 * got.
601 */
602 int fallback_cmd;
603
604 /*
605 * Used for username and password input.
606 */
607 char *userpass_input_buffer;
608 int userpass_input_buflen;
609 int userpass_input_bufpos;
610 int userpass_input_echo;
611
612 char *portfwd_strptr;
613 int pkt_ctx;
614
615 void *x11auth;
616
617 int version;
618 int v1_throttle_count;
619 int overall_bufsize;
620 int throttled_all;
621 int v1_stdout_throttling;
622 int v2_outgoing_sequence;
623
624 int ssh1_rdpkt_crstate;
625 int ssh2_rdpkt_crstate;
626 int do_ssh_init_crstate;
627 int ssh_gotdata_crstate;
628 int ssh1_protocol_crstate;
629 int do_ssh1_login_crstate;
630 int do_ssh2_transport_crstate;
631 int do_ssh2_authconn_crstate;
632
633 void *do_ssh_init_state;
634 void *do_ssh1_login_state;
635 void *do_ssh2_transport_state;
636 void *do_ssh2_authconn_state;
637
638 struct rdpkt1_state_tag rdpkt1_state;
639 struct rdpkt2_state_tag rdpkt2_state;
640
641 void (*protocol) (Ssh ssh, unsigned char *in, int inlen, int ispkt);
642 int (*s_rdpkt) (Ssh ssh, unsigned char **data, int *datalen);
643
644 /*
645 * We maintain a full _copy_ of a Config structure here, not
646 * merely a pointer to it. That way, when we're passed a new
647 * one for reconfiguration, we can check the differences and
648 * potentially reconfigure port forwardings etc in mid-session.
649 */
650 Config cfg;
651 };
652
653 #define logevent(s) logevent(ssh->frontend, s)
654
655 /* logevent, only printf-formatted. */
656 static void logeventf(Ssh ssh, char *fmt, ...)
657 {
658 va_list ap;
659 char *buf;
660
661 va_start(ap, fmt);
662 buf = dupvprintf(fmt, ap);
663 va_end(ap);
664 logevent(buf);
665 sfree(buf);
666 }
667
668 #define bombout(msg) \
669 do { \
670 char *text = dupprintf msg; \
671 ssh->state = SSH_STATE_CLOSED; \
672 if (ssh->s) { sk_close(ssh->s); ssh->s = NULL; } \
673 logevent(text); \
674 connection_fatal(ssh->frontend, "%s", text); \
675 sfree(text); \
676 } while (0)
677
678 static int ssh_channelcmp(void *av, void *bv)
679 {
680 struct ssh_channel *a = (struct ssh_channel *) av;
681 struct ssh_channel *b = (struct ssh_channel *) bv;
682 if (a->localid < b->localid)
683 return -1;
684 if (a->localid > b->localid)
685 return +1;
686 return 0;
687 }
688 static int ssh_channelfind(void *av, void *bv)
689 {
690 unsigned *a = (unsigned *) av;
691 struct ssh_channel *b = (struct ssh_channel *) bv;
692 if (*a < b->localid)
693 return -1;
694 if (*a > b->localid)
695 return +1;
696 return 0;
697 }
698
699 static int ssh_rportcmp_ssh1(void *av, void *bv)
700 {
701 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
702 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
703 int i;
704 if ( (i = strcmp(a->dhost, b->dhost)) != 0)
705 return i < 0 ? -1 : +1;
706 if (a->dport > b->dport)
707 return +1;
708 if (a->dport < b->dport)
709 return -1;
710 return 0;
711 }
712
713 static int ssh_rportcmp_ssh2(void *av, void *bv)
714 {
715 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
716 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
717
718 if (a->sport > b->sport)
719 return +1;
720 if (a->sport < b->sport)
721 return -1;
722 return 0;
723 }
724
725 static int alloc_channel_id(Ssh ssh)
726 {
727 const unsigned CHANNEL_NUMBER_OFFSET = 256;
728 unsigned low, high, mid;
729 int tsize;
730 struct ssh_channel *c;
731
732 /*
733 * First-fit allocation of channel numbers: always pick the
734 * lowest unused one. To do this, binary-search using the
735 * counted B-tree to find the largest channel ID which is in a
736 * contiguous sequence from the beginning. (Precisely
737 * everything in that sequence must have ID equal to its tree
738 * index plus CHANNEL_NUMBER_OFFSET.)
739 */
740 tsize = count234(ssh->channels);
741
742 low = -1;
743 high = tsize;
744 while (high - low > 1) {
745 mid = (high + low) / 2;
746 c = index234(ssh->channels, mid);
747 if (c->localid == mid + CHANNEL_NUMBER_OFFSET)
748 low = mid; /* this one is fine */
749 else
750 high = mid; /* this one is past it */
751 }
752 /*
753 * Now low points to either -1, or the tree index of the
754 * largest ID in the initial sequence.
755 */
756 {
757 unsigned i = low + 1 + CHANNEL_NUMBER_OFFSET;
758 assert(NULL == find234(ssh->channels, &i, ssh_channelfind));
759 }
760 return low + 1 + CHANNEL_NUMBER_OFFSET;
761 }
762
763 static void c_write(Ssh ssh, const char *buf, int len)
764 {
765 if ((flags & FLAG_STDERR)) {
766 int i;
767 for (i = 0; i < len; i++)
768 if (buf[i] != '\r')
769 fputc(buf[i], stderr);
770 return;
771 }
772 from_backend(ssh->frontend, 1, buf, len);
773 }
774
775 static void c_write_untrusted(Ssh ssh, const char *buf, int len)
776 {
777 int i;
778 for (i = 0; i < len; i++) {
779 if (buf[i] == '\n')
780 c_write(ssh, "\r\n", 2);
781 else if ((buf[i] & 0x60) || (buf[i] == '\r'))
782 c_write(ssh, buf + i, 1);
783 }
784 }
785
786 static void c_write_str(Ssh ssh, const char *buf)
787 {
788 c_write(ssh, buf, strlen(buf));
789 }
790
791 /*
792 * Collect incoming data in the incoming packet buffer.
793 * Decipher and verify the packet when it is completely read.
794 * Drop SSH1_MSG_DEBUG and SSH1_MSG_IGNORE packets.
795 * Update the *data and *datalen variables.
796 * Return the additional nr of bytes needed, or 0 when
797 * a complete packet is available.
798 */
799 static int ssh1_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
800 {
801 struct rdpkt1_state_tag *st = &ssh->rdpkt1_state;
802
803 crBegin(ssh->ssh1_rdpkt_crstate);
804
805 next_packet:
806
807 ssh->pktin.type = 0;
808 ssh->pktin.length = 0;
809
810 for (st->i = st->len = 0; st->i < 4; st->i++) {
811 while ((*datalen) == 0)
812 crReturn(4 - st->i);
813 st->len = (st->len << 8) + **data;
814 (*data)++, (*datalen)--;
815 }
816
817 st->pad = 8 - (st->len % 8);
818 st->biglen = st->len + st->pad;
819 ssh->pktin.length = st->len - 5;
820
821 if (ssh->pktin.maxlen < st->biglen) {
822 ssh->pktin.maxlen = st->biglen;
823 ssh->pktin.data = sresize(ssh->pktin.data, st->biglen + APIEXTRA,
824 unsigned char);
825 }
826
827 st->to_read = st->biglen;
828 st->p = ssh->pktin.data;
829 while (st->to_read > 0) {
830 st->chunk = st->to_read;
831 while ((*datalen) == 0)
832 crReturn(st->to_read);
833 if (st->chunk > (*datalen))
834 st->chunk = (*datalen);
835 memcpy(st->p, *data, st->chunk);
836 *data += st->chunk;
837 *datalen -= st->chunk;
838 st->p += st->chunk;
839 st->to_read -= st->chunk;
840 }
841
842 if (ssh->cipher && detect_attack(ssh->crcda_ctx, ssh->pktin.data,
843 st->biglen, NULL)) {
844 bombout(("Network attack (CRC compensation) detected!"));
845 crReturn(0);
846 }
847
848 if (ssh->cipher)
849 ssh->cipher->decrypt(ssh->v1_cipher_ctx, ssh->pktin.data, st->biglen);
850
851 st->realcrc = crc32(ssh->pktin.data, st->biglen - 4);
852 st->gotcrc = GET_32BIT(ssh->pktin.data + st->biglen - 4);
853 if (st->gotcrc != st->realcrc) {
854 bombout(("Incorrect CRC received on packet"));
855 crReturn(0);
856 }
857
858 ssh->pktin.body = ssh->pktin.data + st->pad + 1;
859
860 if (ssh->v1_compressing) {
861 unsigned char *decompblk;
862 int decomplen;
863 zlib_decompress_block(ssh->sc_comp_ctx,
864 ssh->pktin.body - 1, ssh->pktin.length + 1,
865 &decompblk, &decomplen);
866
867 if (ssh->pktin.maxlen < st->pad + decomplen) {
868 ssh->pktin.maxlen = st->pad + decomplen;
869 ssh->pktin.data = sresize(ssh->pktin.data,
870 ssh->pktin.maxlen + APIEXTRA,
871 unsigned char);
872 ssh->pktin.body = ssh->pktin.data + st->pad + 1;
873 }
874
875 memcpy(ssh->pktin.body - 1, decompblk, decomplen);
876 sfree(decompblk);
877 ssh->pktin.length = decomplen - 1;
878 }
879
880 ssh->pktin.type = ssh->pktin.body[-1];
881
882 if (ssh->logctx)
883 log_packet(ssh->logctx,
884 PKT_INCOMING, ssh->pktin.type,
885 ssh1_pkt_type(ssh->pktin.type),
886 ssh->pktin.body, ssh->pktin.length);
887
888 if (ssh->pktin.type == SSH1_SMSG_STDOUT_DATA ||
889 ssh->pktin.type == SSH1_SMSG_STDERR_DATA ||
890 ssh->pktin.type == SSH1_MSG_DEBUG ||
891 ssh->pktin.type == SSH1_SMSG_AUTH_TIS_CHALLENGE ||
892 ssh->pktin.type == SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
893 long stringlen = GET_32BIT(ssh->pktin.body);
894 if (stringlen + 4 != ssh->pktin.length) {
895 bombout(("Received data packet with bogus string length"));
896 crReturn(0);
897 }
898 }
899
900 if (ssh->pktin.type == SSH1_MSG_DEBUG) {
901 /* log debug message */
902 char buf[512];
903 int stringlen = GET_32BIT(ssh->pktin.body);
904 strcpy(buf, "Remote debug message: ");
905 if (stringlen > 480)
906 stringlen = 480;
907 memcpy(buf + 8, ssh->pktin.body + 4, stringlen);
908 buf[8 + stringlen] = '\0';
909 logevent(buf);
910 goto next_packet;
911 } else if (ssh->pktin.type == SSH1_MSG_IGNORE) {
912 /* do nothing */
913 goto next_packet;
914 }
915
916 if (ssh->pktin.type == SSH1_MSG_DISCONNECT) {
917 /* log reason code in disconnect message */
918 char buf[256];
919 unsigned msglen = GET_32BIT(ssh->pktin.body);
920 unsigned nowlen;
921 strcpy(buf, "Remote sent disconnect: ");
922 nowlen = strlen(buf);
923 if (msglen > sizeof(buf) - nowlen - 1)
924 msglen = sizeof(buf) - nowlen - 1;
925 memcpy(buf + nowlen, ssh->pktin.body + 4, msglen);
926 buf[nowlen + msglen] = '\0';
927 /* logevent(buf); (this is now done within the bombout macro) */
928 bombout(("Server sent disconnect message:\n\"%s\"", buf+nowlen));
929 crReturn(0);
930 }
931
932 crFinish(0);
933 }
934
935 static int ssh2_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
936 {
937 struct rdpkt2_state_tag *st = &ssh->rdpkt2_state;
938
939 crBegin(ssh->ssh2_rdpkt_crstate);
940
941 next_packet:
942 ssh->pktin.type = 0;
943 ssh->pktin.length = 0;
944 if (ssh->sccipher)
945 st->cipherblk = ssh->sccipher->blksize;
946 else
947 st->cipherblk = 8;
948 if (st->cipherblk < 8)
949 st->cipherblk = 8;
950
951 if (ssh->pktin.maxlen < st->cipherblk) {
952 ssh->pktin.maxlen = st->cipherblk;
953 ssh->pktin.data = sresize(ssh->pktin.data, st->cipherblk + APIEXTRA,
954 unsigned char);
955 }
956
957 /*
958 * Acquire and decrypt the first block of the packet. This will
959 * contain the length and padding details.
960 */
961 for (st->i = st->len = 0; st->i < st->cipherblk; st->i++) {
962 while ((*datalen) == 0)
963 crReturn(st->cipherblk - st->i);
964 ssh->pktin.data[st->i] = *(*data)++;
965 (*datalen)--;
966 }
967
968 if (ssh->sccipher)
969 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
970 ssh->pktin.data, st->cipherblk);
971
972 /*
973 * Now get the length and padding figures.
974 */
975 st->len = GET_32BIT(ssh->pktin.data);
976 st->pad = ssh->pktin.data[4];
977
978 /*
979 * _Completely_ silly lengths should be stomped on before they
980 * do us any more damage.
981 */
982 if (st->len < 0 || st->pad < 0 || st->len + st->pad < 0) {
983 bombout(("Incoming packet was garbled on decryption"));
984 crReturn(0);
985 }
986
987 /*
988 * This enables us to deduce the payload length.
989 */
990 st->payload = st->len - st->pad - 1;
991
992 ssh->pktin.length = st->payload + 5;
993
994 /*
995 * So now we can work out the total packet length.
996 */
997 st->packetlen = st->len + 4;
998 st->maclen = ssh->scmac ? ssh->scmac->len : 0;
999
1000 /*
1001 * Adjust memory allocation if packet is too big.
1002 */
1003 if (ssh->pktin.maxlen < st->packetlen + st->maclen) {
1004 ssh->pktin.maxlen = st->packetlen + st->maclen;
1005 ssh->pktin.data = sresize(ssh->pktin.data,
1006 ssh->pktin.maxlen + APIEXTRA,
1007 unsigned char);
1008 }
1009
1010 /*
1011 * Read and decrypt the remainder of the packet.
1012 */
1013 for (st->i = st->cipherblk; st->i < st->packetlen + st->maclen;
1014 st->i++) {
1015 while ((*datalen) == 0)
1016 crReturn(st->packetlen + st->maclen - st->i);
1017 ssh->pktin.data[st->i] = *(*data)++;
1018 (*datalen)--;
1019 }
1020 /* Decrypt everything _except_ the MAC. */
1021 if (ssh->sccipher)
1022 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
1023 ssh->pktin.data + st->cipherblk,
1024 st->packetlen - st->cipherblk);
1025
1026 /*
1027 * Check the MAC.
1028 */
1029 if (ssh->scmac
1030 && !ssh->scmac->verify(ssh->sc_mac_ctx, ssh->pktin.data, st->len + 4,
1031 st->incoming_sequence)) {
1032 bombout(("Incorrect MAC received on packet"));
1033 crReturn(0);
1034 }
1035 st->incoming_sequence++; /* whether or not we MACed */
1036
1037 /*
1038 * Decompress packet payload.
1039 */
1040 {
1041 unsigned char *newpayload;
1042 int newlen;
1043 if (ssh->sccomp &&
1044 ssh->sccomp->decompress(ssh->sc_comp_ctx,
1045 ssh->pktin.data + 5, ssh->pktin.length - 5,
1046 &newpayload, &newlen)) {
1047 if (ssh->pktin.maxlen < newlen + 5) {
1048 ssh->pktin.maxlen = newlen + 5;
1049 ssh->pktin.data = sresize(ssh->pktin.data,
1050 ssh->pktin.maxlen + APIEXTRA,
1051 unsigned char);
1052 }
1053 ssh->pktin.length = 5 + newlen;
1054 memcpy(ssh->pktin.data + 5, newpayload, newlen);
1055 sfree(newpayload);
1056 }
1057 }
1058
1059 ssh->pktin.savedpos = 6;
1060 ssh->pktin.type = ssh->pktin.data[5];
1061
1062 if (ssh->logctx)
1063 log_packet(ssh->logctx, PKT_INCOMING, ssh->pktin.type,
1064 ssh2_pkt_type(ssh->pkt_ctx, ssh->pktin.type),
1065 ssh->pktin.data+6, ssh->pktin.length-6);
1066
1067 switch (ssh->pktin.type) {
1068 /*
1069 * These packets we must handle instantly.
1070 */
1071 case SSH2_MSG_DISCONNECT:
1072 {
1073 /* log reason code in disconnect message */
1074 char *buf;
1075 int nowlen;
1076 int reason = GET_32BIT(ssh->pktin.data + 6);
1077 unsigned msglen = GET_32BIT(ssh->pktin.data + 10);
1078
1079 if (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) {
1080 buf = dupprintf("Received disconnect message (%s)",
1081 ssh2_disconnect_reasons[reason]);
1082 } else {
1083 buf = dupprintf("Received disconnect message (unknown"
1084 " type %d)", reason);
1085 }
1086 logevent(buf);
1087 sfree(buf);
1088 buf = dupprintf("Disconnection message text: %n%.*s",
1089 &nowlen, msglen, ssh->pktin.data + 14);
1090 logevent(buf);
1091 bombout(("Server sent disconnect message\ntype %d (%s):\n\"%s\"",
1092 reason,
1093 (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) ?
1094 ssh2_disconnect_reasons[reason] : "unknown",
1095 buf+nowlen));
1096 sfree(buf);
1097 crReturn(0);
1098 }
1099 break;
1100 case SSH2_MSG_IGNORE:
1101 goto next_packet;
1102 case SSH2_MSG_DEBUG:
1103 {
1104 /* log the debug message */
1105 char buf[512];
1106 /* int display = ssh->pktin.body[6]; */
1107 int stringlen = GET_32BIT(ssh->pktin.data+7);
1108 int prefix;
1109 strcpy(buf, "Remote debug message: ");
1110 prefix = strlen(buf);
1111 if (stringlen > (int)(sizeof(buf)-prefix-1))
1112 stringlen = sizeof(buf)-prefix-1;
1113 memcpy(buf + prefix, ssh->pktin.data + 11, stringlen);
1114 buf[prefix + stringlen] = '\0';
1115 logevent(buf);
1116 }
1117 goto next_packet; /* FIXME: print the debug message */
1118
1119 /*
1120 * These packets we need do nothing about here.
1121 */
1122 case SSH2_MSG_UNIMPLEMENTED:
1123 case SSH2_MSG_SERVICE_REQUEST:
1124 case SSH2_MSG_SERVICE_ACCEPT:
1125 case SSH2_MSG_KEXINIT:
1126 case SSH2_MSG_NEWKEYS:
1127 case SSH2_MSG_KEXDH_INIT:
1128 case SSH2_MSG_KEXDH_REPLY:
1129 /* case SSH2_MSG_KEX_DH_GEX_REQUEST: duplicate case value */
1130 /* case SSH2_MSG_KEX_DH_GEX_GROUP: duplicate case value */
1131 case SSH2_MSG_KEX_DH_GEX_INIT:
1132 case SSH2_MSG_KEX_DH_GEX_REPLY:
1133 case SSH2_MSG_USERAUTH_REQUEST:
1134 case SSH2_MSG_USERAUTH_FAILURE:
1135 case SSH2_MSG_USERAUTH_SUCCESS:
1136 case SSH2_MSG_USERAUTH_BANNER:
1137 case SSH2_MSG_USERAUTH_PK_OK:
1138 /* case SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ: duplicate case value */
1139 /* case SSH2_MSG_USERAUTH_INFO_REQUEST: duplicate case value */
1140 case SSH2_MSG_USERAUTH_INFO_RESPONSE:
1141 case SSH2_MSG_GLOBAL_REQUEST:
1142 case SSH2_MSG_REQUEST_SUCCESS:
1143 case SSH2_MSG_REQUEST_FAILURE:
1144 case SSH2_MSG_CHANNEL_OPEN:
1145 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION:
1146 case SSH2_MSG_CHANNEL_OPEN_FAILURE:
1147 case SSH2_MSG_CHANNEL_WINDOW_ADJUST:
1148 case SSH2_MSG_CHANNEL_DATA:
1149 case SSH2_MSG_CHANNEL_EXTENDED_DATA:
1150 case SSH2_MSG_CHANNEL_EOF:
1151 case SSH2_MSG_CHANNEL_CLOSE:
1152 case SSH2_MSG_CHANNEL_REQUEST:
1153 case SSH2_MSG_CHANNEL_SUCCESS:
1154 case SSH2_MSG_CHANNEL_FAILURE:
1155 break;
1156
1157 /*
1158 * For anything else we send SSH2_MSG_UNIMPLEMENTED.
1159 */
1160 default:
1161 ssh2_pkt_init(ssh, SSH2_MSG_UNIMPLEMENTED);
1162 ssh2_pkt_adduint32(ssh, st->incoming_sequence - 1);
1163 ssh2_pkt_send(ssh);
1164 break;
1165 }
1166
1167 crFinish(0);
1168 }
1169
1170 static void ssh1_pktout_size(Ssh ssh, int len)
1171 {
1172 int pad, biglen;
1173
1174 len += 5; /* type and CRC */
1175 pad = 8 - (len % 8);
1176 biglen = len + pad;
1177
1178 ssh->pktout.length = len - 5;
1179 if (ssh->pktout.maxlen < biglen) {
1180 ssh->pktout.maxlen = biglen;
1181 #ifdef MSCRYPTOAPI
1182 /* Allocate enough buffer space for extra block
1183 * for MS CryptEncrypt() */
1184 ssh->pktout.data = sresize(ssh->pktout.data, biglen + 12,
1185 unsigned char);
1186 #else
1187 ssh->pktout.data = sresize(ssh->pktout.data, biglen + 4,
1188 unsigned char);
1189 #endif
1190 }
1191 ssh->pktout.body = ssh->pktout.data + 4 + pad + 1;
1192 }
1193
1194 static void s_wrpkt_start(Ssh ssh, int type, int len)
1195 {
1196 ssh1_pktout_size(ssh, len);
1197 ssh->pktout.type = type;
1198 }
1199
1200 static int s_wrpkt_prepare(Ssh ssh)
1201 {
1202 int pad, biglen, i;
1203 unsigned long crc;
1204 #ifdef __SC__
1205 /*
1206 * XXX various versions of SC (including 8.8.4) screw up the
1207 * register allocation in this function and use the same register
1208 * (D6) for len and as a temporary, with predictable results. The
1209 * following sledgehammer prevents this.
1210 */
1211 volatile
1212 #endif
1213 int len;
1214
1215 ssh->pktout.body[-1] = ssh->pktout.type;
1216
1217 if (ssh->logctx)
1218 log_packet(ssh->logctx, PKT_OUTGOING, ssh->pktout.type,
1219 ssh1_pkt_type(ssh->pktout.type),
1220 ssh->pktout.body, ssh->pktout.length);
1221
1222 if (ssh->v1_compressing) {
1223 unsigned char *compblk;
1224 int complen;
1225 zlib_compress_block(ssh->cs_comp_ctx,
1226 ssh->pktout.body - 1, ssh->pktout.length + 1,
1227 &compblk, &complen);
1228 ssh1_pktout_size(ssh, complen - 1);
1229 memcpy(ssh->pktout.body - 1, compblk, complen);
1230 sfree(compblk);
1231 }
1232
1233 len = ssh->pktout.length + 5; /* type and CRC */
1234 pad = 8 - (len % 8);
1235 biglen = len + pad;
1236
1237 for (i = 0; i < pad; i++)
1238 ssh->pktout.data[i + 4] = random_byte();
1239 crc = crc32(ssh->pktout.data + 4, biglen - 4);
1240 PUT_32BIT(ssh->pktout.data + biglen, crc);
1241 PUT_32BIT(ssh->pktout.data, len);
1242
1243 if (ssh->cipher)
1244 ssh->cipher->encrypt(ssh->v1_cipher_ctx, ssh->pktout.data + 4, biglen);
1245
1246 return biglen + 4;
1247 }
1248
1249 static void s_wrpkt(Ssh ssh)
1250 {
1251 int len, backlog;
1252 len = s_wrpkt_prepare(ssh);
1253 backlog = sk_write(ssh->s, (char *)ssh->pktout.data, len);
1254 if (backlog > SSH_MAX_BACKLOG)
1255 ssh_throttle_all(ssh, 1, backlog);
1256 }
1257
1258 static void s_wrpkt_defer(Ssh ssh)
1259 {
1260 int len;
1261 len = s_wrpkt_prepare(ssh);
1262 if (ssh->deferred_len + len > ssh->deferred_size) {
1263 ssh->deferred_size = ssh->deferred_len + len + 128;
1264 ssh->deferred_send_data = sresize(ssh->deferred_send_data,
1265 ssh->deferred_size,
1266 unsigned char);
1267 }
1268 memcpy(ssh->deferred_send_data + ssh->deferred_len, ssh->pktout.data, len);
1269 ssh->deferred_len += len;
1270 }
1271
1272 /*
1273 * Construct a packet with the specified contents.
1274 */
1275 static void construct_packet(Ssh ssh, int pkttype, va_list ap1, va_list ap2)
1276 {
1277 unsigned char *p, *argp, argchar;
1278 unsigned long argint;
1279 int pktlen, argtype, arglen;
1280 Bignum bn;
1281
1282 pktlen = 0;
1283 while ((argtype = va_arg(ap1, int)) != PKT_END) {
1284 switch (argtype) {
1285 case PKT_INT:
1286 (void) va_arg(ap1, int);
1287 pktlen += 4;
1288 break;
1289 case PKT_CHAR:
1290 (void) va_arg(ap1, int);
1291 pktlen++;
1292 break;
1293 case PKT_DATA:
1294 (void) va_arg(ap1, unsigned char *);
1295 arglen = va_arg(ap1, int);
1296 pktlen += arglen;
1297 break;
1298 case PKT_STR:
1299 argp = va_arg(ap1, unsigned char *);
1300 arglen = strlen((char *)argp);
1301 pktlen += 4 + arglen;
1302 break;
1303 case PKT_BIGNUM:
1304 bn = va_arg(ap1, Bignum);
1305 pktlen += ssh1_bignum_length(bn);
1306 break;
1307 default:
1308 assert(0);
1309 }
1310 }
1311
1312 s_wrpkt_start(ssh, pkttype, pktlen);
1313 p = ssh->pktout.body;
1314
1315 while ((argtype = va_arg(ap2, int)) != PKT_END) {
1316 switch (argtype) {
1317 case PKT_INT:
1318 argint = va_arg(ap2, int);
1319 PUT_32BIT(p, argint);
1320 p += 4;
1321 break;
1322 case PKT_CHAR:
1323 argchar = (unsigned char) va_arg(ap2, int);
1324 *p = argchar;
1325 p++;
1326 break;
1327 case PKT_DATA:
1328 argp = va_arg(ap2, unsigned char *);
1329 arglen = va_arg(ap2, int);
1330 memcpy(p, argp, arglen);
1331 p += arglen;
1332 break;
1333 case PKT_STR:
1334 argp = va_arg(ap2, unsigned char *);
1335 arglen = strlen((char *)argp);
1336 PUT_32BIT(p, arglen);
1337 memcpy(p + 4, argp, arglen);
1338 p += 4 + arglen;
1339 break;
1340 case PKT_BIGNUM:
1341 bn = va_arg(ap2, Bignum);
1342 p += ssh1_write_bignum(p, bn);
1343 break;
1344 }
1345 }
1346 }
1347
1348 static void send_packet(Ssh ssh, int pkttype, ...)
1349 {
1350 va_list ap1, ap2;
1351 va_start(ap1, pkttype);
1352 va_start(ap2, pkttype);
1353 construct_packet(ssh, pkttype, ap1, ap2);
1354 s_wrpkt(ssh);
1355 }
1356
1357 static void defer_packet(Ssh ssh, int pkttype, ...)
1358 {
1359 va_list ap1, ap2;
1360 va_start(ap1, pkttype);
1361 va_start(ap2, pkttype);
1362 construct_packet(ssh, pkttype, ap1, ap2);
1363 s_wrpkt_defer(ssh);
1364 }
1365
1366 static int ssh_versioncmp(char *a, char *b)
1367 {
1368 char *ae, *be;
1369 unsigned long av, bv;
1370
1371 av = strtoul(a, &ae, 10);
1372 bv = strtoul(b, &be, 10);
1373 if (av != bv)
1374 return (av < bv ? -1 : +1);
1375 if (*ae == '.')
1376 ae++;
1377 if (*be == '.')
1378 be++;
1379 av = strtoul(ae, &ae, 10);
1380 bv = strtoul(be, &be, 10);
1381 if (av != bv)
1382 return (av < bv ? -1 : +1);
1383 return 0;
1384 }
1385
1386 /*
1387 * Utility routines for putting an SSH-protocol `string' and
1388 * `uint32' into a SHA state.
1389 */
1390 #include <stdio.h>
1391 static void sha_string(SHA_State * s, void *str, int len)
1392 {
1393 unsigned char lenblk[4];
1394 PUT_32BIT(lenblk, len);
1395 SHA_Bytes(s, lenblk, 4);
1396 SHA_Bytes(s, str, len);
1397 }
1398
1399 static void sha_uint32(SHA_State * s, unsigned i)
1400 {
1401 unsigned char intblk[4];
1402 PUT_32BIT(intblk, i);
1403 SHA_Bytes(s, intblk, 4);
1404 }
1405
1406 /*
1407 * SSH2 packet construction functions.
1408 */
1409 static void ssh2_pkt_ensure(Ssh ssh, int length)
1410 {
1411 if (ssh->pktout.maxlen < length) {
1412 ssh->pktout.maxlen = length + 256;
1413 ssh->pktout.data = sresize(ssh->pktout.data,
1414 ssh->pktout.maxlen + APIEXTRA,
1415 unsigned char);
1416 if (!ssh->pktout.data)
1417 fatalbox("Out of memory");
1418 }
1419 }
1420 static void ssh2_pkt_adddata(Ssh ssh, void *data, int len)
1421 {
1422 ssh->pktout.length += len;
1423 ssh2_pkt_ensure(ssh, ssh->pktout.length);
1424 memcpy(ssh->pktout.data + ssh->pktout.length - len, data, len);
1425 }
1426 static void ssh2_pkt_addbyte(Ssh ssh, unsigned char byte)
1427 {
1428 ssh2_pkt_adddata(ssh, &byte, 1);
1429 }
1430 static void ssh2_pkt_init(Ssh ssh, int pkt_type)
1431 {
1432 ssh->pktout.length = 5;
1433 ssh2_pkt_addbyte(ssh, (unsigned char) pkt_type);
1434 }
1435 static void ssh2_pkt_addbool(Ssh ssh, unsigned char value)
1436 {
1437 ssh2_pkt_adddata(ssh, &value, 1);
1438 }
1439 static void ssh2_pkt_adduint32(Ssh ssh, unsigned long value)
1440 {
1441 unsigned char x[4];
1442 PUT_32BIT(x, value);
1443 ssh2_pkt_adddata(ssh, x, 4);
1444 }
1445 static void ssh2_pkt_addstring_start(Ssh ssh)
1446 {
1447 ssh2_pkt_adduint32(ssh, 0);
1448 ssh->pktout.savedpos = ssh->pktout.length;
1449 }
1450 static void ssh2_pkt_addstring_str(Ssh ssh, char *data)
1451 {
1452 ssh2_pkt_adddata(ssh, data, strlen(data));
1453 PUT_32BIT(ssh->pktout.data + ssh->pktout.savedpos - 4,
1454 ssh->pktout.length - ssh->pktout.savedpos);
1455 }
1456 static void ssh2_pkt_addstring_data(Ssh ssh, char *data, int len)
1457 {
1458 ssh2_pkt_adddata(ssh, data, len);
1459 PUT_32BIT(ssh->pktout.data + ssh->pktout.savedpos - 4,
1460 ssh->pktout.length - ssh->pktout.savedpos);
1461 }
1462 static void ssh2_pkt_addstring(Ssh ssh, char *data)
1463 {
1464 ssh2_pkt_addstring_start(ssh);
1465 ssh2_pkt_addstring_str(ssh, data);
1466 }
1467 static unsigned char *ssh2_mpint_fmt(Bignum b, int *len)
1468 {
1469 unsigned char *p;
1470 int i, n = (bignum_bitcount(b) + 7) / 8;
1471 p = snewn(n + 1, unsigned char);
1472 if (!p)
1473 fatalbox("out of memory");
1474 p[0] = 0;
1475 for (i = 1; i <= n; i++)
1476 p[i] = bignum_byte(b, n - i);
1477 i = 0;
1478 while (i <= n && p[i] == 0 && (p[i + 1] & 0x80) == 0)
1479 i++;
1480 memmove(p, p + i, n + 1 - i);
1481 *len = n + 1 - i;
1482 return p;
1483 }
1484 static void ssh2_pkt_addmp(Ssh ssh, Bignum b)
1485 {
1486 unsigned char *p;
1487 int len;
1488 p = ssh2_mpint_fmt(b, &len);
1489 ssh2_pkt_addstring_start(ssh);
1490 ssh2_pkt_addstring_data(ssh, (char *)p, len);
1491 sfree(p);
1492 }
1493
1494 /*
1495 * Construct an SSH2 final-form packet: compress it, encrypt it,
1496 * put the MAC on it. Final packet, ready to be sent, is stored in
1497 * ssh->pktout.data. Total length is returned.
1498 */
1499 static int ssh2_pkt_construct(Ssh ssh)
1500 {
1501 int cipherblk, maclen, padding, i;
1502
1503 if (ssh->logctx)
1504 log_packet(ssh->logctx, PKT_OUTGOING, ssh->pktout.data[5],
1505 ssh2_pkt_type(ssh->pkt_ctx, ssh->pktout.data[5]),
1506 ssh->pktout.data + 6, ssh->pktout.length - 6);
1507
1508 /*
1509 * Compress packet payload.
1510 */
1511 {
1512 unsigned char *newpayload;
1513 int newlen;
1514 if (ssh->cscomp &&
1515 ssh->cscomp->compress(ssh->cs_comp_ctx, ssh->pktout.data + 5,
1516 ssh->pktout.length - 5,
1517 &newpayload, &newlen)) {
1518 ssh->pktout.length = 5;
1519 ssh2_pkt_adddata(ssh, newpayload, newlen);
1520 sfree(newpayload);
1521 }
1522 }
1523
1524 /*
1525 * Add padding. At least four bytes, and must also bring total
1526 * length (minus MAC) up to a multiple of the block size.
1527 */
1528 cipherblk = ssh->cscipher ? ssh->cscipher->blksize : 8; /* block size */
1529 cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */
1530 padding = 4;
1531 padding +=
1532 (cipherblk - (ssh->pktout.length + padding) % cipherblk) % cipherblk;
1533 maclen = ssh->csmac ? ssh->csmac->len : 0;
1534 ssh2_pkt_ensure(ssh, ssh->pktout.length + padding + maclen);
1535 ssh->pktout.data[4] = padding;
1536 for (i = 0; i < padding; i++)
1537 ssh->pktout.data[ssh->pktout.length + i] = random_byte();
1538 PUT_32BIT(ssh->pktout.data, ssh->pktout.length + padding - 4);
1539 if (ssh->csmac)
1540 ssh->csmac->generate(ssh->cs_mac_ctx, ssh->pktout.data,
1541 ssh->pktout.length + padding,
1542 ssh->v2_outgoing_sequence);
1543 ssh->v2_outgoing_sequence++; /* whether or not we MACed */
1544
1545 if (ssh->cscipher)
1546 ssh->cscipher->encrypt(ssh->cs_cipher_ctx,
1547 ssh->pktout.data, ssh->pktout.length + padding);
1548
1549 /* Ready-to-send packet starts at ssh->pktout.data. We return length. */
1550 return ssh->pktout.length + padding + maclen;
1551 }
1552
1553 /*
1554 * Construct and send an SSH2 packet immediately.
1555 */
1556 static void ssh2_pkt_send(Ssh ssh)
1557 {
1558 int len;
1559 int backlog;
1560 len = ssh2_pkt_construct(ssh);
1561 backlog = sk_write(ssh->s, (char *)ssh->pktout.data, len);
1562 if (backlog > SSH_MAX_BACKLOG)
1563 ssh_throttle_all(ssh, 1, backlog);
1564 }
1565
1566 /*
1567 * Construct an SSH2 packet and add it to a deferred data block.
1568 * Useful for sending multiple packets in a single sk_write() call,
1569 * to prevent a traffic-analysing listener from being able to work
1570 * out the length of any particular packet (such as the password
1571 * packet).
1572 *
1573 * Note that because SSH2 sequence-numbers its packets, this can
1574 * NOT be used as an m4-style `defer' allowing packets to be
1575 * constructed in one order and sent in another.
1576 */
1577 static void ssh2_pkt_defer(Ssh ssh)
1578 {
1579 int len = ssh2_pkt_construct(ssh);
1580 if (ssh->deferred_len + len > ssh->deferred_size) {
1581 ssh->deferred_size = ssh->deferred_len + len + 128;
1582 ssh->deferred_send_data = sresize(ssh->deferred_send_data,
1583 ssh->deferred_size,
1584 unsigned char);
1585 }
1586 memcpy(ssh->deferred_send_data + ssh->deferred_len, ssh->pktout.data, len);
1587 ssh->deferred_len += len;
1588 }
1589
1590 /*
1591 * Send the whole deferred data block constructed by
1592 * ssh2_pkt_defer() or SSH1's defer_packet().
1593 */
1594 static void ssh_pkt_defersend(Ssh ssh)
1595 {
1596 int backlog;
1597 backlog = sk_write(ssh->s, (char *)ssh->deferred_send_data,
1598 ssh->deferred_len);
1599 ssh->deferred_len = ssh->deferred_size = 0;
1600 sfree(ssh->deferred_send_data);
1601 ssh->deferred_send_data = NULL;
1602 if (backlog > SSH_MAX_BACKLOG)
1603 ssh_throttle_all(ssh, 1, backlog);
1604 }
1605
1606 #if 0
1607 void bndebug(char *string, Bignum b)
1608 {
1609 unsigned char *p;
1610 int i, len;
1611 p = ssh2_mpint_fmt(b, &len);
1612 debug(("%s", string));
1613 for (i = 0; i < len; i++)
1614 debug((" %02x", p[i]));
1615 debug(("\n"));
1616 sfree(p);
1617 }
1618 #endif
1619
1620 static void sha_mpint(SHA_State * s, Bignum b)
1621 {
1622 unsigned char *p;
1623 int len;
1624 p = ssh2_mpint_fmt(b, &len);
1625 sha_string(s, p, len);
1626 sfree(p);
1627 }
1628
1629 /*
1630 * SSH2 packet decode functions.
1631 */
1632 static unsigned long ssh2_pkt_getuint32(Ssh ssh)
1633 {
1634 unsigned long value;
1635 if (ssh->pktin.length - ssh->pktin.savedpos < 4)
1636 return 0; /* arrgh, no way to decline (FIXME?) */
1637 value = GET_32BIT(ssh->pktin.data + ssh->pktin.savedpos);
1638 ssh->pktin.savedpos += 4;
1639 return value;
1640 }
1641 static int ssh2_pkt_getbool(Ssh ssh)
1642 {
1643 unsigned long value;
1644 if (ssh->pktin.length - ssh->pktin.savedpos < 1)
1645 return 0; /* arrgh, no way to decline (FIXME?) */
1646 value = ssh->pktin.data[ssh->pktin.savedpos] != 0;
1647 ssh->pktin.savedpos++;
1648 return value;
1649 }
1650 static void ssh2_pkt_getstring(Ssh ssh, char **p, int *length)
1651 {
1652 int len;
1653 *p = NULL;
1654 *length = 0;
1655 if (ssh->pktin.length - ssh->pktin.savedpos < 4)
1656 return;
1657 len = GET_32BIT(ssh->pktin.data + ssh->pktin.savedpos);
1658 if (len < 0)
1659 return;
1660 *length = len;
1661 ssh->pktin.savedpos += 4;
1662 if (ssh->pktin.length - ssh->pktin.savedpos < *length)
1663 return;
1664 *p = (char *)(ssh->pktin.data + ssh->pktin.savedpos);
1665 ssh->pktin.savedpos += *length;
1666 }
1667 static Bignum ssh2_pkt_getmp(Ssh ssh)
1668 {
1669 char *p;
1670 int length;
1671 Bignum b;
1672
1673 ssh2_pkt_getstring(ssh, &p, &length);
1674 if (!p)
1675 return NULL;
1676 if (p[0] & 0x80) {
1677 bombout(("internal error: Can't handle negative mpints"));
1678 return NULL;
1679 }
1680 b = bignum_from_bytes((unsigned char *)p, length);
1681 return b;
1682 }
1683
1684 /*
1685 * Helper function to add an SSH2 signature blob to a packet.
1686 * Expects to be shown the public key blob as well as the signature
1687 * blob. Normally works just like ssh2_pkt_addstring, but will
1688 * fiddle with the signature packet if necessary for
1689 * BUG_SSH2_RSA_PADDING.
1690 */
1691 static void ssh2_add_sigblob(Ssh ssh, void *pkblob_v, int pkblob_len,
1692 void *sigblob_v, int sigblob_len)
1693 {
1694 unsigned char *pkblob = (unsigned char *)pkblob_v;
1695 unsigned char *sigblob = (unsigned char *)sigblob_v;
1696
1697 /* dmemdump(pkblob, pkblob_len); */
1698 /* dmemdump(sigblob, sigblob_len); */
1699
1700 /*
1701 * See if this is in fact an ssh-rsa signature and a buggy
1702 * server; otherwise we can just do this the easy way.
1703 */
1704 if ((ssh->remote_bugs & BUG_SSH2_RSA_PADDING) &&
1705 (GET_32BIT(pkblob) == 7 && !memcmp(pkblob+4, "ssh-rsa", 7))) {
1706 int pos, len, siglen;
1707
1708 /*
1709 * Find the byte length of the modulus.
1710 */
1711
1712 pos = 4+7; /* skip over "ssh-rsa" */
1713 pos += 4 + GET_32BIT(pkblob+pos); /* skip over exponent */
1714 len = GET_32BIT(pkblob+pos); /* find length of modulus */
1715 pos += 4; /* find modulus itself */
1716 while (len > 0 && pkblob[pos] == 0)
1717 len--, pos++;
1718 /* debug(("modulus length is %d\n", len)); */
1719
1720 /*
1721 * Now find the signature integer.
1722 */
1723 pos = 4+7; /* skip over "ssh-rsa" */
1724 siglen = GET_32BIT(sigblob+pos);
1725 /* debug(("signature length is %d\n", siglen)); */
1726
1727 if (len != siglen) {
1728 unsigned char newlen[4];
1729 ssh2_pkt_addstring_start(ssh);
1730 ssh2_pkt_addstring_data(ssh, (char *)sigblob, pos);
1731 /* dmemdump(sigblob, pos); */
1732 pos += 4; /* point to start of actual sig */
1733 PUT_32BIT(newlen, len);
1734 ssh2_pkt_addstring_data(ssh, (char *)newlen, 4);
1735 /* dmemdump(newlen, 4); */
1736 newlen[0] = 0;
1737 while (len-- > siglen) {
1738 ssh2_pkt_addstring_data(ssh, (char *)newlen, 1);
1739 /* dmemdump(newlen, 1); */
1740 }
1741 ssh2_pkt_addstring_data(ssh, (char *)(sigblob+pos), siglen);
1742 /* dmemdump(sigblob+pos, siglen); */
1743 return;
1744 }
1745
1746 /* Otherwise fall through and do it the easy way. */
1747 }
1748
1749 ssh2_pkt_addstring_start(ssh);
1750 ssh2_pkt_addstring_data(ssh, (char *)sigblob, sigblob_len);
1751 }
1752
1753 /*
1754 * Examine the remote side's version string and compare it against
1755 * a list of known buggy implementations.
1756 */
1757 static void ssh_detect_bugs(Ssh ssh, char *vstring)
1758 {
1759 char *imp; /* pointer to implementation part */
1760 imp = vstring;
1761 imp += strcspn(imp, "-");
1762 if (*imp) imp++;
1763 imp += strcspn(imp, "-");
1764 if (*imp) imp++;
1765
1766 ssh->remote_bugs = 0;
1767
1768 if (ssh->cfg.sshbug_ignore1 == FORCE_ON ||
1769 (ssh->cfg.sshbug_ignore1 == AUTO &&
1770 (!strcmp(imp, "1.2.18") || !strcmp(imp, "1.2.19") ||
1771 !strcmp(imp, "1.2.20") || !strcmp(imp, "1.2.21") ||
1772 !strcmp(imp, "1.2.22") || !strcmp(imp, "Cisco-1.25")))) {
1773 /*
1774 * These versions don't support SSH1_MSG_IGNORE, so we have
1775 * to use a different defence against password length
1776 * sniffing.
1777 */
1778 ssh->remote_bugs |= BUG_CHOKES_ON_SSH1_IGNORE;
1779 logevent("We believe remote version has SSH1 ignore bug");
1780 }
1781
1782 if (ssh->cfg.sshbug_plainpw1 == FORCE_ON ||
1783 (ssh->cfg.sshbug_plainpw1 == AUTO &&
1784 (!strcmp(imp, "Cisco-1.25")))) {
1785 /*
1786 * These versions need a plain password sent; they can't
1787 * handle having a null and a random length of data after
1788 * the password.
1789 */
1790 ssh->remote_bugs |= BUG_NEEDS_SSH1_PLAIN_PASSWORD;
1791 logevent("We believe remote version needs a plain SSH1 password");
1792 }
1793
1794 if (ssh->cfg.sshbug_rsa1 == FORCE_ON ||
1795 (ssh->cfg.sshbug_rsa1 == AUTO &&
1796 (!strcmp(imp, "Cisco-1.25")))) {
1797 /*
1798 * These versions apparently have no clue whatever about
1799 * RSA authentication and will panic and die if they see
1800 * an AUTH_RSA message.
1801 */
1802 ssh->remote_bugs |= BUG_CHOKES_ON_RSA;
1803 logevent("We believe remote version can't handle RSA authentication");
1804 }
1805
1806 if (ssh->cfg.sshbug_hmac2 == FORCE_ON ||
1807 (ssh->cfg.sshbug_hmac2 == AUTO &&
1808 (wc_match("2.1.0*", imp) || wc_match("2.0.*", imp) ||
1809 wc_match("2.2.0*", imp) || wc_match("2.3.0*", imp) ||
1810 wc_match("2.1 *", imp)))) {
1811 /*
1812 * These versions have the HMAC bug.
1813 */
1814 ssh->remote_bugs |= BUG_SSH2_HMAC;
1815 logevent("We believe remote version has SSH2 HMAC bug");
1816 }
1817
1818 if (ssh->cfg.sshbug_derivekey2 == FORCE_ON ||
1819 (ssh->cfg.sshbug_derivekey2 == AUTO &&
1820 (wc_match("2.0.0*", imp) || wc_match("2.0.10*", imp) ))) {
1821 /*
1822 * These versions have the key-derivation bug (failing to
1823 * include the literal shared secret in the hashes that
1824 * generate the keys).
1825 */
1826 ssh->remote_bugs |= BUG_SSH2_DERIVEKEY;
1827 logevent("We believe remote version has SSH2 key-derivation bug");
1828 }
1829
1830 if (ssh->cfg.sshbug_rsapad2 == FORCE_ON ||
1831 (ssh->cfg.sshbug_rsapad2 == AUTO &&
1832 (wc_match("OpenSSH_2.[5-9]*", imp) ||
1833 wc_match("OpenSSH_3.[0-2]*", imp)))) {
1834 /*
1835 * These versions have the SSH2 RSA padding bug.
1836 */
1837 ssh->remote_bugs |= BUG_SSH2_RSA_PADDING;
1838 logevent("We believe remote version has SSH2 RSA padding bug");
1839 }
1840
1841 if (ssh->cfg.sshbug_pksessid2 == FORCE_ON ||
1842 (ssh->cfg.sshbug_pksessid2 == AUTO &&
1843 wc_match("OpenSSH_2.[0-2]*", imp))) {
1844 /*
1845 * These versions have the SSH2 session-ID bug in
1846 * public-key authentication.
1847 */
1848 ssh->remote_bugs |= BUG_SSH2_PK_SESSIONID;
1849 logevent("We believe remote version has SSH2 public-key-session-ID bug");
1850 }
1851
1852 if (ssh->cfg.sshbug_dhgex2 == FORCE_ON) {
1853 /*
1854 * User specified the SSH2 DH GEX bug.
1855 */
1856 ssh->remote_bugs |= BUG_SSH2_DH_GEX;
1857 logevent("We believe remote version has SSH2 DH group exchange bug");
1858 }
1859 }
1860
1861 static int do_ssh_init(Ssh ssh, unsigned char c)
1862 {
1863 struct do_ssh_init_state {
1864 int vslen;
1865 char version[10];
1866 char *vstring;
1867 int vstrsize;
1868 int i;
1869 int proto1, proto2;
1870 };
1871 crState(do_ssh_init_state);
1872
1873 crBegin(ssh->do_ssh_init_crstate);
1874
1875 /* Search for the string "SSH-" in the input. */
1876 s->i = 0;
1877 while (1) {
1878 static const int transS[] = { 1, 2, 2, 1 };
1879 static const int transH[] = { 0, 0, 3, 0 };
1880 static const int transminus[] = { 0, 0, 0, -1 };
1881 if (c == 'S')
1882 s->i = transS[s->i];
1883 else if (c == 'H')
1884 s->i = transH[s->i];
1885 else if (c == '-')
1886 s->i = transminus[s->i];
1887 else
1888 s->i = 0;
1889 if (s->i < 0)
1890 break;
1891 crReturn(1); /* get another character */
1892 }
1893
1894 s->vstrsize = 16;
1895 s->vstring = snewn(s->vstrsize, char);
1896 strcpy(s->vstring, "SSH-");
1897 s->vslen = 4;
1898 s->i = 0;
1899 while (1) {
1900 crReturn(1); /* get another char */
1901 if (s->vslen >= s->vstrsize - 1) {
1902 s->vstrsize += 16;
1903 s->vstring = sresize(s->vstring, s->vstrsize, char);
1904 }
1905 s->vstring[s->vslen++] = c;
1906 if (s->i >= 0) {
1907 if (c == '-') {
1908 s->version[s->i] = '\0';
1909 s->i = -1;
1910 } else if (s->i < sizeof(s->version) - 1)
1911 s->version[s->i++] = c;
1912 } else if (c == '\012')
1913 break;
1914 }
1915
1916 ssh->agentfwd_enabled = FALSE;
1917 ssh->rdpkt2_state.incoming_sequence = 0;
1918
1919 s->vstring[s->vslen] = 0;
1920 s->vstring[strcspn(s->vstring, "\r\n")] = '\0';/* remove EOL chars */
1921 {
1922 char *vlog;
1923 vlog = snewn(20 + s->vslen, char);
1924 sprintf(vlog, "Server version: %s", s->vstring);
1925 logevent(vlog);
1926 sfree(vlog);
1927 }
1928 ssh_detect_bugs(ssh, s->vstring);
1929
1930 /*
1931 * Decide which SSH protocol version to support.
1932 */
1933
1934 /* Anything strictly below "2.0" means protocol 1 is supported. */
1935 s->proto1 = ssh_versioncmp(s->version, "2.0") < 0;
1936 /* Anything greater or equal to "1.99" means protocol 2 is supported. */
1937 s->proto2 = ssh_versioncmp(s->version, "1.99") >= 0;
1938
1939 if (ssh->cfg.sshprot == 0 && !s->proto1) {
1940 bombout(("SSH protocol version 1 required by user but not provided by server"));
1941 crReturn(0);
1942 }
1943 if (ssh->cfg.sshprot == 3 && !s->proto2) {
1944 bombout(("SSH protocol version 2 required by user but not provided by server"));
1945 crReturn(0);
1946 }
1947
1948 if (s->proto2 && (ssh->cfg.sshprot >= 2 || !s->proto1)) {
1949 /*
1950 * Use v2 protocol.
1951 */
1952 char verstring[80], vlog[100];
1953 sprintf(verstring, "SSH-2.0-%s", sshver);
1954 SHA_Init(&ssh->exhashbase);
1955 /*
1956 * Hash our version string and their version string.
1957 */
1958 sha_string(&ssh->exhashbase, verstring, strlen(verstring));
1959 sha_string(&ssh->exhashbase, s->vstring, strcspn(s->vstring, "\r\n"));
1960 sprintf(vlog, "We claim version: %s", verstring);
1961 logevent(vlog);
1962 strcat(verstring, "\012");
1963 logevent("Using SSH protocol version 2");
1964 sk_write(ssh->s, verstring, strlen(verstring));
1965 ssh->protocol = ssh2_protocol;
1966 ssh->version = 2;
1967 ssh->s_rdpkt = ssh2_rdpkt;
1968 } else {
1969 /*
1970 * Use v1 protocol.
1971 */
1972 char verstring[80], vlog[100];
1973 sprintf(verstring, "SSH-%s-%s",
1974 (ssh_versioncmp(s->version, "1.5") <= 0 ? s->version : "1.5"),
1975 sshver);
1976 sprintf(vlog, "We claim version: %s", verstring);
1977 logevent(vlog);
1978 strcat(verstring, "\012");
1979
1980 logevent("Using SSH protocol version 1");
1981 sk_write(ssh->s, verstring, strlen(verstring));
1982 ssh->protocol = ssh1_protocol;
1983 ssh->version = 1;
1984 ssh->s_rdpkt = ssh1_rdpkt;
1985 }
1986 ssh->state = SSH_STATE_BEFORE_SIZE;
1987
1988 sfree(s->vstring);
1989
1990 crFinish(0);
1991 }
1992
1993 static void ssh_gotdata(Ssh ssh, unsigned char *data, int datalen)
1994 {
1995 crBegin(ssh->ssh_gotdata_crstate);
1996
1997 /*
1998 * To begin with, feed the characters one by one to the
1999 * protocol initialisation / selection function do_ssh_init().
2000 * When that returns 0, we're done with the initial greeting
2001 * exchange and can move on to packet discipline.
2002 */
2003 while (1) {
2004 int ret; /* need not be kept across crReturn */
2005 if (datalen == 0)
2006 crReturnV; /* more data please */
2007 ret = do_ssh_init(ssh, *data);
2008 data++;
2009 datalen--;
2010 if (ret == 0)
2011 break;
2012 }
2013
2014 /*
2015 * We emerge from that loop when the initial negotiation is
2016 * over and we have selected an s_rdpkt function. Now pass
2017 * everything to s_rdpkt, and then pass the resulting packets
2018 * to the proper protocol handler.
2019 */
2020 if (datalen == 0)
2021 crReturnV;
2022 while (1) {
2023 while (datalen > 0) {
2024 if (ssh->s_rdpkt(ssh, &data, &datalen) == 0) {
2025 if (ssh->state == SSH_STATE_CLOSED) {
2026 return;
2027 }
2028 ssh->protocol(ssh, NULL, 0, 1);
2029 if (ssh->state == SSH_STATE_CLOSED) {
2030 return;
2031 }
2032 }
2033 }
2034 crReturnV;
2035 }
2036 crFinishV;
2037 }
2038
2039 static int ssh_closing(Plug plug, char *error_msg, int error_code,
2040 int calling_back)
2041 {
2042 Ssh ssh = (Ssh) plug;
2043 ssh->state = SSH_STATE_CLOSED;
2044 if (ssh->s) {
2045 sk_close(ssh->s);
2046 ssh->s = NULL;
2047 }
2048 if (error_msg) {
2049 /* A socket error has occurred. */
2050 logevent(error_msg);
2051 connection_fatal(ssh->frontend, error_msg);
2052 } else {
2053 /* Otherwise, the remote side closed the connection normally. */
2054 }
2055 return 0;
2056 }
2057
2058 static int ssh_receive(Plug plug, int urgent, char *data, int len)
2059 {
2060 Ssh ssh = (Ssh) plug;
2061 ssh_gotdata(ssh, (unsigned char *)data, len);
2062 if (ssh->state == SSH_STATE_CLOSED) {
2063 if (ssh->s) {
2064 sk_close(ssh->s);
2065 ssh->s = NULL;
2066 }
2067 return 0;
2068 }
2069 return 1;
2070 }
2071
2072 static void ssh_sent(Plug plug, int bufsize)
2073 {
2074 Ssh ssh = (Ssh) plug;
2075 /*
2076 * If the send backlog on the SSH socket itself clears, we
2077 * should unthrottle the whole world if it was throttled.
2078 */
2079 if (bufsize < SSH_MAX_BACKLOG)
2080 ssh_throttle_all(ssh, 0, bufsize);
2081 }
2082
2083 /*
2084 * Connect to specified host and port.
2085 * Returns an error message, or NULL on success.
2086 * Also places the canonical host name into `realhost'. It must be
2087 * freed by the caller.
2088 */
2089 static char *connect_to_host(Ssh ssh, char *host, int port,
2090 char **realhost, int nodelay)
2091 {
2092 static const struct plug_function_table fn_table = {
2093 ssh_closing,
2094 ssh_receive,
2095 ssh_sent,
2096 NULL
2097 };
2098
2099 SockAddr addr;
2100 char *err;
2101
2102 ssh->savedhost = snewn(1 + strlen(host), char);
2103 if (!ssh->savedhost)
2104 fatalbox("Out of memory");
2105 strcpy(ssh->savedhost, host);
2106
2107 if (port < 0)
2108 port = 22; /* default ssh port */
2109 ssh->savedport = port;
2110
2111 /*
2112 * Try to find host.
2113 */
2114 logeventf(ssh, "Looking up host \"%s\"", host);
2115 addr = name_lookup(host, port, realhost, &ssh->cfg);
2116 if ((err = sk_addr_error(addr)) != NULL)
2117 return err;
2118
2119 /*
2120 * Open socket.
2121 */
2122 {
2123 char addrbuf[100];
2124 sk_getaddr(addr, addrbuf, 100);
2125 logeventf(ssh, "Connecting to %s port %d", addrbuf, port);
2126 }
2127 ssh->fn = &fn_table;
2128 ssh->s = new_connection(addr, *realhost, port,
2129 0, 1, nodelay, (Plug) ssh, &ssh->cfg);
2130 if ((err = sk_socket_error(ssh->s)) != NULL) {
2131 ssh->s = NULL;
2132 return err;
2133 }
2134
2135 return NULL;
2136 }
2137
2138 /*
2139 * Throttle or unthrottle the SSH connection.
2140 */
2141 static void ssh1_throttle(Ssh ssh, int adjust)
2142 {
2143 int old_count = ssh->v1_throttle_count;
2144 ssh->v1_throttle_count += adjust;
2145 assert(ssh->v1_throttle_count >= 0);
2146 if (ssh->v1_throttle_count && !old_count) {
2147 sk_set_frozen(ssh->s, 1);
2148 } else if (!ssh->v1_throttle_count && old_count) {
2149 sk_set_frozen(ssh->s, 0);
2150 }
2151 }
2152
2153 /*
2154 * Throttle or unthrottle _all_ local data streams (for when sends
2155 * on the SSH connection itself back up).
2156 */
2157 static void ssh_throttle_all(Ssh ssh, int enable, int bufsize)
2158 {
2159 int i;
2160 struct ssh_channel *c;
2161
2162 if (enable == ssh->throttled_all)
2163 return;
2164 ssh->throttled_all = enable;
2165 ssh->overall_bufsize = bufsize;
2166 if (!ssh->channels)
2167 return;
2168 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
2169 switch (c->type) {
2170 case CHAN_MAINSESSION:
2171 /*
2172 * This is treated separately, outside the switch.
2173 */
2174 break;
2175 case CHAN_X11:
2176 x11_override_throttle(c->u.x11.s, enable);
2177 break;
2178 case CHAN_AGENT:
2179 /* Agent channels require no buffer management. */
2180 break;
2181 case CHAN_SOCKDATA:
2182 pfd_override_throttle(c->u.x11.s, enable);
2183 break;
2184 }
2185 }
2186 }
2187
2188 /*
2189 * Username and password input, abstracted off into routines
2190 * reusable in several places - even between SSH1 and SSH2.
2191 */
2192
2193 /* Set up a username or password input loop on a given buffer. */
2194 static void setup_userpass_input(Ssh ssh, char *buffer, int buflen, int echo)
2195 {
2196 ssh->userpass_input_buffer = buffer;
2197 ssh->userpass_input_buflen = buflen;
2198 ssh->userpass_input_bufpos = 0;
2199 ssh->userpass_input_echo = echo;
2200 }
2201
2202 /*
2203 * Process some terminal data in the course of username/password
2204 * input. Returns >0 for success (line of input returned in
2205 * buffer), <0 for failure (user hit ^C/^D, bomb out and exit), 0
2206 * for inconclusive (keep waiting for more input please).
2207 */
2208 static int process_userpass_input(Ssh ssh, unsigned char *in, int inlen)
2209 {
2210 char c;
2211
2212 while (inlen--) {
2213 switch (c = *in++) {
2214 case 10:
2215 case 13:
2216 ssh->userpass_input_buffer[ssh->userpass_input_bufpos] = 0;
2217 ssh->userpass_input_buffer[ssh->userpass_input_buflen-1] = 0;
2218 return +1;
2219 break;
2220 case 8:
2221 case 127:
2222 if (ssh->userpass_input_bufpos > 0) {
2223 if (ssh->userpass_input_echo)
2224 c_write_str(ssh, "\b \b");
2225 ssh->userpass_input_bufpos--;
2226 }
2227 break;
2228 case 21:
2229 case 27:
2230 while (ssh->userpass_input_bufpos > 0) {
2231 if (ssh->userpass_input_echo)
2232 c_write_str(ssh, "\b \b");
2233 ssh->userpass_input_bufpos--;
2234 }
2235 break;
2236 case 3:
2237 case 4:
2238 return -1;
2239 break;
2240 default:
2241 /*
2242 * This simplistic check for printability is disabled
2243 * when we're doing password input, because some people
2244 * have control characters in their passwords.o
2245 */
2246 if ((!ssh->userpass_input_echo ||
2247 (c >= ' ' && c <= '~') ||
2248 ((unsigned char) c >= 160))
2249 && ssh->userpass_input_bufpos < ssh->userpass_input_buflen-1) {
2250 ssh->userpass_input_buffer[ssh->userpass_input_bufpos++] = c;
2251 if (ssh->userpass_input_echo)
2252 c_write(ssh, &c, 1);
2253 }
2254 break;
2255 }
2256 }
2257 return 0;
2258 }
2259
2260 /*
2261 * Handle the key exchange and user authentication phases.
2262 */
2263 static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
2264 {
2265 int i, j;
2266 unsigned char cookie[8];
2267 struct RSAKey servkey, hostkey;
2268 struct MD5Context md5c;
2269 struct do_ssh1_login_state {
2270 int len;
2271 unsigned char *rsabuf, *keystr1, *keystr2;
2272 unsigned long supported_ciphers_mask, supported_auths_mask;
2273 int tried_publickey, tried_agent;
2274 int tis_auth_refused, ccard_auth_refused;
2275 unsigned char session_id[16];
2276 int cipher_type;
2277 char username[100];
2278 void *publickey_blob;
2279 int publickey_bloblen;
2280 char password[100];
2281 char prompt[200];
2282 int pos;
2283 char c;
2284 int pwpkt_type;
2285 unsigned char request[5], *response, *p;
2286 int responselen;
2287 int keyi, nkeys;
2288 int authed;
2289 struct RSAKey key;
2290 Bignum challenge;
2291 char *commentp;
2292 int commentlen;
2293 };
2294 crState(do_ssh1_login_state);
2295
2296 crBegin(ssh->do_ssh1_login_crstate);
2297
2298 if (!ispkt)
2299 crWaitUntil(ispkt);
2300
2301 if (ssh->pktin.type != SSH1_SMSG_PUBLIC_KEY) {
2302 bombout(("Public key packet not received"));
2303 crReturn(0);
2304 }
2305
2306 logevent("Received public keys");
2307
2308 memcpy(cookie, ssh->pktin.body, 8);
2309
2310 i = makekey(ssh->pktin.body + 8, &servkey, &s->keystr1, 0);
2311 j = makekey(ssh->pktin.body + 8 + i, &hostkey, &s->keystr2, 0);
2312
2313 /*
2314 * Log the host key fingerprint.
2315 */
2316 {
2317 char logmsg[80];
2318 logevent("Host key fingerprint is:");
2319 strcpy(logmsg, " ");
2320 hostkey.comment = NULL;
2321 rsa_fingerprint(logmsg + strlen(logmsg),
2322 sizeof(logmsg) - strlen(logmsg), &hostkey);
2323 logevent(logmsg);
2324 }
2325
2326 ssh->v1_remote_protoflags = GET_32BIT(ssh->pktin.body + 8 + i + j);
2327 s->supported_ciphers_mask = GET_32BIT(ssh->pktin.body + 12 + i + j);
2328 s->supported_auths_mask = GET_32BIT(ssh->pktin.body + 16 + i + j);
2329
2330 ssh->v1_local_protoflags =
2331 ssh->v1_remote_protoflags & SSH1_PROTOFLAGS_SUPPORTED;
2332 ssh->v1_local_protoflags |= SSH1_PROTOFLAG_SCREEN_NUMBER;
2333
2334 MD5Init(&md5c);
2335 MD5Update(&md5c, s->keystr2, hostkey.bytes);
2336 MD5Update(&md5c, s->keystr1, servkey.bytes);
2337 MD5Update(&md5c, ssh->pktin.body, 8);
2338 MD5Final(s->session_id, &md5c);
2339
2340 for (i = 0; i < 32; i++)
2341 ssh->session_key[i] = random_byte();
2342
2343 s->len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes);
2344
2345 s->rsabuf = snewn(s->len, unsigned char);
2346 if (!s->rsabuf)
2347 fatalbox("Out of memory");
2348
2349 /*
2350 * Verify the host key.
2351 */
2352 {
2353 /*
2354 * First format the key into a string.
2355 */
2356 int len = rsastr_len(&hostkey);
2357 char fingerprint[100];
2358 char *keystr = snewn(len, char);
2359 if (!keystr)
2360 fatalbox("Out of memory");
2361 rsastr_fmt(keystr, &hostkey);
2362 rsa_fingerprint(fingerprint, sizeof(fingerprint), &hostkey);
2363 verify_ssh_host_key(ssh->frontend,
2364 ssh->savedhost, ssh->savedport, "rsa", keystr,
2365 fingerprint);
2366 sfree(keystr);
2367 }
2368
2369 for (i = 0; i < 32; i++) {
2370 s->rsabuf[i] = ssh->session_key[i];
2371 if (i < 16)
2372 s->rsabuf[i] ^= s->session_id[i];
2373 }
2374
2375 if (hostkey.bytes > servkey.bytes) {
2376 rsaencrypt(s->rsabuf, 32, &servkey);
2377 rsaencrypt(s->rsabuf, servkey.bytes, &hostkey);
2378 } else {
2379 rsaencrypt(s->rsabuf, 32, &hostkey);
2380 rsaencrypt(s->rsabuf, hostkey.bytes, &servkey);
2381 }
2382
2383 logevent("Encrypted session key");
2384
2385 {
2386 int cipher_chosen = 0, warn = 0;
2387 char *cipher_string = NULL;
2388 int i;
2389 for (i = 0; !cipher_chosen && i < CIPHER_MAX; i++) {
2390 int next_cipher = ssh->cfg.ssh_cipherlist[i];
2391 if (next_cipher == CIPHER_WARN) {
2392 /* If/when we choose a cipher, warn about it */
2393 warn = 1;
2394 } else if (next_cipher == CIPHER_AES) {
2395 /* XXX Probably don't need to mention this. */
2396 logevent("AES not supported in SSH1, skipping");
2397 } else {
2398 switch (next_cipher) {
2399 case CIPHER_3DES: s->cipher_type = SSH_CIPHER_3DES;
2400 cipher_string = "3DES"; break;
2401 case CIPHER_BLOWFISH: s->cipher_type = SSH_CIPHER_BLOWFISH;
2402 cipher_string = "Blowfish"; break;
2403 case CIPHER_DES: s->cipher_type = SSH_CIPHER_DES;
2404 cipher_string = "single-DES"; break;
2405 }
2406 if (s->supported_ciphers_mask & (1 << s->cipher_type))
2407 cipher_chosen = 1;
2408 }
2409 }
2410 if (!cipher_chosen) {
2411 if ((s->supported_ciphers_mask & (1 << SSH_CIPHER_3DES)) == 0)
2412 bombout(("Server violates SSH 1 protocol by not "
2413 "supporting 3DES encryption"));
2414 else
2415 /* shouldn't happen */
2416 bombout(("No supported ciphers found"));
2417 crReturn(0);
2418 }
2419
2420 /* Warn about chosen cipher if necessary. */
2421 if (warn)
2422 askcipher(ssh->frontend, cipher_string, 0);
2423 }
2424
2425 switch (s->cipher_type) {
2426 case SSH_CIPHER_3DES:
2427 logevent("Using 3DES encryption");
2428 break;
2429 case SSH_CIPHER_DES:
2430 logevent("Using single-DES encryption");
2431 break;
2432 case SSH_CIPHER_BLOWFISH:
2433 logevent("Using Blowfish encryption");
2434 break;
2435 }
2436
2437 send_packet(ssh, SSH1_CMSG_SESSION_KEY,
2438 PKT_CHAR, s->cipher_type,
2439 PKT_DATA, cookie, 8,
2440 PKT_CHAR, (s->len * 8) >> 8, PKT_CHAR, (s->len * 8) & 0xFF,
2441 PKT_DATA, s->rsabuf, s->len,
2442 PKT_INT, ssh->v1_local_protoflags, PKT_END);
2443
2444 logevent("Trying to enable encryption...");
2445
2446 sfree(s->rsabuf);
2447
2448 ssh->cipher = (s->cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 :
2449 s->cipher_type == SSH_CIPHER_DES ? &ssh_des :
2450 &ssh_3des);
2451 ssh->v1_cipher_ctx = ssh->cipher->make_context();
2452 ssh->cipher->sesskey(ssh->v1_cipher_ctx, ssh->session_key);
2453 logeventf(ssh, "Initialised %s encryption", ssh->cipher->text_name);
2454
2455 ssh->crcda_ctx = crcda_make_context();
2456 logevent("Installing CRC compensation attack detector");
2457
2458 crWaitUntil(ispkt);
2459
2460 if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
2461 bombout(("Encryption not successfully enabled"));
2462 crReturn(0);
2463 }
2464
2465 logevent("Successfully started encryption");
2466
2467 fflush(stdout);
2468 {
2469 if ((flags & FLAG_INTERACTIVE) && !*ssh->cfg.username) {
2470 if (ssh_get_line && !ssh_getline_pw_only) {
2471 if (!ssh_get_line("login as: ",
2472 s->username, sizeof(s->username), FALSE)) {
2473 /*
2474 * get_line failed to get a username.
2475 * Terminate.
2476 */
2477 logevent("No username provided. Abandoning session.");
2478 ssh_closing((Plug)ssh, NULL, 0, 0);
2479 crReturn(1);
2480 }
2481 } else {
2482 int ret; /* need not be kept over crReturn */
2483 c_write_str(ssh, "login as: ");
2484 ssh->send_ok = 1;
2485
2486 setup_userpass_input(ssh, s->username, sizeof(s->username), 1);
2487 do {
2488 crWaitUntil(!ispkt);
2489 ret = process_userpass_input(ssh, in, inlen);
2490 } while (ret == 0);
2491 if (ret < 0)
2492 cleanup_exit(0);
2493 c_write_str(ssh, "\r\n");
2494 }
2495 } else {
2496 strncpy(s->username, ssh->cfg.username, sizeof(s->username));
2497 s->username[sizeof(s->username)-1] = '\0';
2498 }
2499
2500 send_packet(ssh, SSH1_CMSG_USER, PKT_STR, s->username, PKT_END);
2501 {
2502 char userlog[22 + sizeof(s->username)];
2503 sprintf(userlog, "Sent username \"%s\"", s->username);
2504 logevent(userlog);
2505 if (flags & FLAG_INTERACTIVE &&
2506 (!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) {
2507 strcat(userlog, "\r\n");
2508 c_write_str(ssh, userlog);
2509 }
2510 }
2511 }
2512
2513 crWaitUntil(ispkt);
2514
2515 if ((ssh->remote_bugs & BUG_CHOKES_ON_RSA)) {
2516 /* We must not attempt PK auth. Pretend we've already tried it. */
2517 s->tried_publickey = s->tried_agent = 1;
2518 } else {
2519 s->tried_publickey = s->tried_agent = 0;
2520 }
2521 s->tis_auth_refused = s->ccard_auth_refused = 0;
2522 /* Load the public half of ssh->cfg.keyfile so we notice if it's in Pageant */
2523 if (!filename_is_null(ssh->cfg.keyfile)) {
2524 if (!rsakey_pubblob(&ssh->cfg.keyfile,
2525 &s->publickey_blob, &s->publickey_bloblen))
2526 s->publickey_blob = NULL;
2527 } else
2528 s->publickey_blob = NULL;
2529
2530 while (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2531 s->pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
2532
2533 if (agent_exists() && !s->tried_agent) {
2534 /*
2535 * Attempt RSA authentication using Pageant.
2536 */
2537 void *r;
2538
2539 s->authed = FALSE;
2540 s->tried_agent = 1;
2541 logevent("Pageant is running. Requesting keys.");
2542
2543 /* Request the keys held by the agent. */
2544 PUT_32BIT(s->request, 1);
2545 s->request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES;
2546 agent_query(s->request, 5, &r, &s->responselen);
2547 s->response = (unsigned char *) r;
2548 if (s->response && s->responselen >= 5 &&
2549 s->response[4] == SSH1_AGENT_RSA_IDENTITIES_ANSWER) {
2550 s->p = s->response + 5;
2551 s->nkeys = GET_32BIT(s->p);
2552 s->p += 4;
2553 {
2554 char buf[64];
2555 sprintf(buf, "Pageant has %d SSH1 keys", s->nkeys);
2556 logevent(buf);
2557 }
2558 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
2559 {
2560 char buf[64];
2561 sprintf(buf, "Trying Pageant key #%d", s->keyi);
2562 logevent(buf);
2563 }
2564 if (s->publickey_blob &&
2565 !memcmp(s->p, s->publickey_blob,
2566 s->publickey_bloblen)) {
2567 logevent("This key matches configured key file");
2568 s->tried_publickey = 1;
2569 }
2570 s->p += 4;
2571 s->p += ssh1_read_bignum(s->p, &s->key.exponent);
2572 s->p += ssh1_read_bignum(s->p, &s->key.modulus);
2573 s->commentlen = GET_32BIT(s->p);
2574 s->p += 4;
2575 s->commentp = (char *)s->p;
2576 s->p += s->commentlen;
2577 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
2578 PKT_BIGNUM, s->key.modulus, PKT_END);
2579 crWaitUntil(ispkt);
2580 if (ssh->pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
2581 logevent("Key refused");
2582 continue;
2583 }
2584 logevent("Received RSA challenge");
2585 ssh1_read_bignum(ssh->pktin.body, &s->challenge);
2586 {
2587 char *agentreq, *q, *ret;
2588 void *vret;
2589 int len, retlen;
2590 len = 1 + 4; /* message type, bit count */
2591 len += ssh1_bignum_length(s->key.exponent);
2592 len += ssh1_bignum_length(s->key.modulus);
2593 len += ssh1_bignum_length(s->challenge);
2594 len += 16; /* session id */
2595 len += 4; /* response format */
2596 agentreq = snewn(4 + len, char);
2597 PUT_32BIT(agentreq, len);
2598 q = agentreq + 4;
2599 *q++ = SSH1_AGENTC_RSA_CHALLENGE;
2600 PUT_32BIT(q, bignum_bitcount(s->key.modulus));
2601 q += 4;
2602 q += ssh1_write_bignum(q, s->key.exponent);
2603 q += ssh1_write_bignum(q, s->key.modulus);
2604 q += ssh1_write_bignum(q, s->challenge);
2605 memcpy(q, s->session_id, 16);
2606 q += 16;
2607 PUT_32BIT(q, 1); /* response format */
2608 agent_query(agentreq, len + 4, &vret, &retlen);
2609 ret = vret;
2610 sfree(agentreq);
2611 if (ret) {
2612 if (ret[4] == SSH1_AGENT_RSA_RESPONSE) {
2613 logevent("Sending Pageant's response");
2614 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
2615 PKT_DATA, ret + 5, 16,
2616 PKT_END);
2617 sfree(ret);
2618 crWaitUntil(ispkt);
2619 if (ssh->pktin.type == SSH1_SMSG_SUCCESS) {
2620 logevent
2621 ("Pageant's response accepted");
2622 if (flags & FLAG_VERBOSE) {
2623 c_write_str(ssh, "Authenticated using"
2624 " RSA key \"");
2625 c_write(ssh, s->commentp,
2626 s->commentlen);
2627 c_write_str(ssh, "\" from agent\r\n");
2628 }
2629 s->authed = TRUE;
2630 } else
2631 logevent
2632 ("Pageant's response not accepted");
2633 } else {
2634 logevent
2635 ("Pageant failed to answer challenge");
2636 sfree(ret);
2637 }
2638 } else {
2639 logevent("No reply received from Pageant");
2640 }
2641 }
2642 freebn(s->key.exponent);
2643 freebn(s->key.modulus);
2644 freebn(s->challenge);
2645 if (s->authed)
2646 break;
2647 }
2648 }
2649 if (s->authed)
2650 break;
2651 }
2652 if (!filename_is_null(ssh->cfg.keyfile) && !s->tried_publickey)
2653 s->pwpkt_type = SSH1_CMSG_AUTH_RSA;
2654
2655 if (ssh->cfg.try_tis_auth &&
2656 (s->supported_auths_mask & (1 << SSH1_AUTH_TIS)) &&
2657 !s->tis_auth_refused) {
2658 s->pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
2659 logevent("Requested TIS authentication");
2660 send_packet(ssh, SSH1_CMSG_AUTH_TIS, PKT_END);
2661 crWaitUntil(ispkt);
2662 if (ssh->pktin.type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
2663 logevent("TIS authentication declined");
2664 if (flags & FLAG_INTERACTIVE)
2665 c_write_str(ssh, "TIS authentication refused.\r\n");
2666 s->tis_auth_refused = 1;
2667 continue;
2668 } else {
2669 int challengelen = GET_32BIT(ssh->pktin.body);
2670 logevent("Received TIS challenge");
2671 if (challengelen > sizeof(s->prompt) - 1)
2672 challengelen = sizeof(s->prompt) - 1;/* prevent overrun */
2673 memcpy(s->prompt, ssh->pktin.body + 4, challengelen);
2674 /* Prompt heuristic comes from OpenSSH */
2675 strncpy(s->prompt + challengelen,
2676 memchr(s->prompt, '\n', challengelen) ?
2677 "": "\r\nResponse: ",
2678 (sizeof s->prompt) - challengelen);
2679 s->prompt[(sizeof s->prompt) - 1] = '\0';
2680 }
2681 }
2682 if (ssh->cfg.try_tis_auth &&
2683 (s->supported_auths_mask & (1 << SSH1_AUTH_CCARD)) &&
2684 !s->ccard_auth_refused) {
2685 s->pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE;
2686 logevent("Requested CryptoCard authentication");
2687 send_packet(ssh, SSH1_CMSG_AUTH_CCARD, PKT_END);
2688 crWaitUntil(ispkt);
2689 if (ssh->pktin.type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
2690 logevent("CryptoCard authentication declined");
2691 c_write_str(ssh, "CryptoCard authentication refused.\r\n");
2692 s->ccard_auth_refused = 1;
2693 continue;
2694 } else {
2695 int challengelen = GET_32BIT(ssh->pktin.body);
2696 logevent("Received CryptoCard challenge");
2697 if (challengelen > sizeof(s->prompt) - 1)
2698 challengelen = sizeof(s->prompt) - 1;/* prevent overrun */
2699 memcpy(s->prompt, ssh->pktin.body + 4, challengelen);
2700 strncpy(s->prompt + challengelen,
2701 memchr(s->prompt, '\n', challengelen) ?
2702 "" : "\r\nResponse: ",
2703 sizeof(s->prompt) - challengelen);
2704 s->prompt[sizeof(s->prompt) - 1] = '\0';
2705 }
2706 }
2707 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
2708 sprintf(s->prompt, "%.90s@%.90s's password: ",
2709 s->username, ssh->savedhost);
2710 }
2711 if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) {
2712 char *comment = NULL;
2713 int type;
2714 char msgbuf[256];
2715 if (flags & FLAG_VERBOSE)
2716 c_write_str(ssh, "Trying public key authentication.\r\n");
2717 logeventf(ssh, "Trying public key \"%s\"",
2718 filename_to_str(&ssh->cfg.keyfile));
2719 type = key_type(&ssh->cfg.keyfile);
2720 if (type != SSH_KEYTYPE_SSH1) {
2721 sprintf(msgbuf, "Key is of wrong type (%s)",
2722 key_type_to_str(type));
2723 logevent(msgbuf);
2724 c_write_str(ssh, msgbuf);
2725 c_write_str(ssh, "\r\n");
2726 s->tried_publickey = 1;
2727 continue;
2728 }
2729 if (!rsakey_encrypted(&ssh->cfg.keyfile, &comment)) {
2730 if (flags & FLAG_VERBOSE)
2731 c_write_str(ssh, "No passphrase required.\r\n");
2732 goto tryauth;
2733 }
2734 sprintf(s->prompt, "Passphrase for key \"%.100s\": ", comment);
2735 sfree(comment);
2736 }
2737
2738 /*
2739 * Show password prompt, having first obtained it via a TIS
2740 * or CryptoCard exchange if we're doing TIS or CryptoCard
2741 * authentication.
2742 */
2743 if (ssh_get_line) {
2744 if (!ssh_get_line(s->prompt, s->password,
2745 sizeof(s->password), TRUE)) {
2746 /*
2747 * get_line failed to get a password (for example
2748 * because one was supplied on the command line
2749 * which has already failed to work). Terminate.
2750 */
2751 send_packet(ssh, SSH1_MSG_DISCONNECT,
2752 PKT_STR, "No more passwords available to try",
2753 PKT_END);
2754 logevent("Unable to authenticate");
2755 connection_fatal(ssh->frontend, "Unable to authenticate");
2756 ssh_closing((Plug)ssh, NULL, 0, 0);
2757 crReturn(1);
2758 }
2759 } else {
2760 /* Prompt may have come from server. We've munged it a bit, so
2761 * we know it to be zero-terminated at least once. */
2762 int ret; /* need not be saved over crReturn */
2763 c_write_untrusted(ssh, s->prompt, strlen(s->prompt));
2764 s->pos = 0;
2765
2766 setup_userpass_input(ssh, s->password, sizeof(s->password), 0);
2767 do {
2768 crWaitUntil(!ispkt);
2769 ret = process_userpass_input(ssh, in, inlen);
2770 } while (ret == 0);
2771 if (ret < 0)
2772 cleanup_exit(0);
2773 c_write_str(ssh, "\r\n");
2774 }
2775
2776 tryauth:
2777 if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) {
2778 /*
2779 * Try public key authentication with the specified
2780 * key file.
2781 */
2782 s->tried_publickey = 1;
2783
2784 {
2785 int ret = loadrsakey(&ssh->cfg.keyfile, &s->key, s->password);
2786 if (ret == 0) {
2787 c_write_str(ssh, "Couldn't load private key from ");
2788 c_write_str(ssh, filename_to_str(&ssh->cfg.keyfile));
2789 c_write_str(ssh, ".\r\n");
2790 continue; /* go and try password */
2791 }
2792 if (ret == -1) {
2793 c_write_str(ssh, "Wrong passphrase.\r\n");
2794 s->tried_publickey = 0;
2795 continue; /* try again */
2796 }
2797 }
2798
2799 /*
2800 * Send a public key attempt.
2801 */
2802 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
2803 PKT_BIGNUM, s->key.modulus, PKT_END);
2804
2805 crWaitUntil(ispkt);
2806 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2807 c_write_str(ssh, "Server refused our public key.\r\n");
2808 continue; /* go and try password */
2809 }
2810 if (ssh->pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
2811 bombout(("Bizarre response to offer of public key"));
2812 crReturn(0);
2813 }
2814
2815 {
2816 int i;
2817 unsigned char buffer[32];
2818 Bignum challenge, response;
2819
2820 ssh1_read_bignum(ssh->pktin.body, &challenge);
2821 response = rsadecrypt(challenge, &s->key);
2822 freebn(s->key.private_exponent);/* burn the evidence */
2823
2824 for (i = 0; i < 32; i++) {
2825 buffer[i] = bignum_byte(response, 31 - i);
2826 }
2827
2828 MD5Init(&md5c);
2829 MD5Update(&md5c, buffer, 32);
2830 MD5Update(&md5c, s->session_id, 16);
2831 MD5Final(buffer, &md5c);
2832
2833 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
2834 PKT_DATA, buffer, 16, PKT_END);
2835
2836 freebn(challenge);
2837 freebn(response);
2838 }
2839
2840 crWaitUntil(ispkt);
2841 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2842 if (flags & FLAG_VERBOSE)
2843 c_write_str(ssh, "Failed to authenticate with"
2844 " our public key.\r\n");
2845 continue; /* go and try password */
2846 } else if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
2847 bombout(("Bizarre response to RSA authentication response"));
2848 crReturn(0);
2849 }
2850
2851 break; /* we're through! */
2852 } else {
2853 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
2854 /*
2855 * Defence against traffic analysis: we send a
2856 * whole bunch of packets containing strings of
2857 * different lengths. One of these strings is the
2858 * password, in a SSH1_CMSG_AUTH_PASSWORD packet.
2859 * The others are all random data in
2860 * SSH1_MSG_IGNORE packets. This way a passive
2861 * listener can't tell which is the password, and
2862 * hence can't deduce the password length.
2863 *
2864 * Anybody with a password length greater than 16
2865 * bytes is going to have enough entropy in their
2866 * password that a listener won't find it _that_
2867 * much help to know how long it is. So what we'll
2868 * do is:
2869 *
2870 * - if password length < 16, we send 15 packets
2871 * containing string lengths 1 through 15
2872 *
2873 * - otherwise, we let N be the nearest multiple
2874 * of 8 below the password length, and send 8
2875 * packets containing string lengths N through
2876 * N+7. This won't obscure the order of
2877 * magnitude of the password length, but it will
2878 * introduce a bit of extra uncertainty.
2879 *
2880 * A few servers (the old 1.2.18 through 1.2.22)
2881 * can't deal with SSH1_MSG_IGNORE. For these
2882 * servers, we need an alternative defence. We make
2883 * use of the fact that the password is interpreted
2884 * as a C string: so we can append a NUL, then some
2885 * random data.
2886 *
2887 * One server (a Cisco one) can deal with neither
2888 * SSH1_MSG_IGNORE _nor_ a padded password string.
2889 * For this server we are left with no defences
2890 * against password length sniffing.
2891 */
2892 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE)) {
2893 /*
2894 * The server can deal with SSH1_MSG_IGNORE, so
2895 * we can use the primary defence.
2896 */
2897 int bottom, top, pwlen, i;
2898 char *randomstr;
2899
2900 pwlen = strlen(s->password);
2901 if (pwlen < 16) {
2902 bottom = 0; /* zero length passwords are OK! :-) */
2903 top = 15;
2904 } else {
2905 bottom = pwlen & ~7;
2906 top = bottom + 7;
2907 }
2908
2909 assert(pwlen >= bottom && pwlen <= top);
2910
2911 randomstr = snewn(top + 1, char);
2912
2913 for (i = bottom; i <= top; i++) {
2914 if (i == pwlen)
2915 defer_packet(ssh, s->pwpkt_type,
2916 PKT_STR, s->password, PKT_END);
2917 else {
2918 for (j = 0; j < i; j++) {
2919 do {
2920 randomstr[j] = random_byte();
2921 } while (randomstr[j] == '\0');
2922 }
2923 randomstr[i] = '\0';
2924 defer_packet(ssh, SSH1_MSG_IGNORE,
2925 PKT_STR, randomstr, PKT_END);
2926 }
2927 }
2928 logevent("Sending password with camouflage packets");
2929 ssh_pkt_defersend(ssh);
2930 }
2931 else if (!(ssh->remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) {
2932 /*
2933 * The server can't deal with SSH1_MSG_IGNORE
2934 * but can deal with padded passwords, so we
2935 * can use the secondary defence.
2936 */
2937 char string[64];
2938 char *ss;
2939 int len;
2940
2941 len = strlen(s->password);
2942 if (len < sizeof(string)) {
2943 ss = string;
2944 strcpy(string, s->password);
2945 len++; /* cover the zero byte */
2946 while (len < sizeof(string)) {
2947 string[len++] = (char) random_byte();
2948 }
2949 } else {
2950 ss = s->password;
2951 }
2952 logevent("Sending length-padded password");
2953 send_packet(ssh, s->pwpkt_type, PKT_INT, len,
2954 PKT_DATA, ss, len, PKT_END);
2955 } else {
2956 /*
2957 * The server has _both_
2958 * BUG_CHOKES_ON_SSH1_IGNORE and
2959 * BUG_NEEDS_SSH1_PLAIN_PASSWORD. There is
2960 * therefore nothing we can do.
2961 */
2962 int len;
2963 len = strlen(s->password);
2964 logevent("Sending unpadded password");
2965 send_packet(ssh, s->pwpkt_type, PKT_INT, len,
2966 PKT_DATA, s->password, len, PKT_END);
2967 }
2968 } else {
2969 send_packet(ssh, s->pwpkt_type, PKT_STR, s->password, PKT_END);
2970 }
2971 }
2972 logevent("Sent password");
2973 memset(s->password, 0, strlen(s->password));
2974 crWaitUntil(ispkt);
2975 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2976 if (flags & FLAG_VERBOSE)
2977 c_write_str(ssh, "Access denied\r\n");
2978 logevent("Authentication refused");
2979 } else if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
2980 bombout(("Strange packet received, type %d", ssh->pktin.type));
2981 crReturn(0);
2982 }
2983 }
2984
2985 logevent("Authentication successful");
2986
2987 crFinish(1);
2988 }
2989
2990 void sshfwd_close(struct ssh_channel *c)
2991 {
2992 Ssh ssh = c->ssh;
2993
2994 if (c && !c->closes) {
2995 /*
2996 * If the channel's remoteid is -1, we have sent
2997 * CHANNEL_OPEN for this channel, but it hasn't even been
2998 * acknowledged by the server. So we must set a close flag
2999 * on it now, and then when the server acks the channel
3000 * open, we can close it then.
3001 */
3002 if (((int)c->remoteid) != -1) {
3003 if (ssh->version == 1) {
3004 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid,
3005 PKT_END);
3006 } else {
3007 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
3008 ssh2_pkt_adduint32(ssh, c->remoteid);
3009 ssh2_pkt_send(ssh);
3010 }
3011 }
3012 c->closes = 1; /* sent MSG_CLOSE */
3013 if (c->type == CHAN_X11) {
3014 c->u.x11.s = NULL;
3015 logevent("Forwarded X11 connection terminated");
3016 } else if (c->type == CHAN_SOCKDATA ||
3017 c->type == CHAN_SOCKDATA_DORMANT) {
3018 c->u.pfd.s = NULL;
3019 logevent("Forwarded port closed");
3020 }
3021 }
3022 }
3023
3024 int sshfwd_write(struct ssh_channel *c, char *buf, int len)
3025 {
3026 Ssh ssh = c->ssh;
3027
3028 if (ssh->version == 1) {
3029 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
3030 PKT_INT, c->remoteid,
3031 PKT_INT, len, PKT_DATA, buf, len, PKT_END);
3032 /*
3033 * In SSH1 we can return 0 here - implying that forwarded
3034 * connections are never individually throttled - because
3035 * the only circumstance that can cause throttling will be
3036 * the whole SSH connection backing up, in which case
3037 * _everything_ will be throttled as a whole.
3038 */
3039 return 0;
3040 } else {
3041 ssh2_add_channel_data(c, buf, len);
3042 return ssh2_try_send(c);
3043 }
3044 }
3045
3046 void sshfwd_unthrottle(struct ssh_channel *c, int bufsize)
3047 {
3048 Ssh ssh = c->ssh;
3049
3050 if (ssh->version == 1) {
3051 if (c->v.v1.throttling && bufsize < SSH1_BUFFER_LIMIT) {
3052 c->v.v1.throttling = 0;
3053 ssh1_throttle(ssh, -1);
3054 }
3055 } else {
3056 ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
3057 }
3058 }
3059
3060 static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
3061 {
3062 crBegin(ssh->ssh1_protocol_crstate);
3063
3064 random_init();
3065
3066 while (!do_ssh1_login(ssh, in, inlen, ispkt)) {
3067 crReturnV;
3068 }
3069 if (ssh->state == SSH_STATE_CLOSED)
3070 crReturnV;
3071
3072 if (ssh->cfg.agentfwd && agent_exists()) {
3073 logevent("Requesting agent forwarding");
3074 send_packet(ssh, SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END);
3075 do {
3076 crReturnV;
3077 } while (!ispkt);
3078 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3079 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3080 bombout(("Protocol confusion"));
3081 crReturnV;
3082 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3083 logevent("Agent forwarding refused");
3084 } else {
3085 logevent("Agent forwarding enabled");
3086 ssh->agentfwd_enabled = TRUE;
3087 }
3088 }
3089
3090 if (ssh->cfg.x11_forward) {
3091 char proto[20], data[64];
3092 logevent("Requesting X11 forwarding");
3093 ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
3094 data, sizeof(data), ssh->cfg.x11_auth);
3095 x11_get_real_auth(ssh->x11auth, ssh->cfg.x11_display);
3096 if (ssh->v1_local_protoflags & SSH1_PROTOFLAG_SCREEN_NUMBER) {
3097 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
3098 PKT_STR, proto, PKT_STR, data,
3099 PKT_INT, x11_get_screen_number(ssh->cfg.x11_display),
3100 PKT_END);
3101 } else {
3102 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
3103 PKT_STR, proto, PKT_STR, data, PKT_END);
3104 }
3105 do {
3106 crReturnV;
3107 } while (!ispkt);
3108 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3109 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3110 bombout(("Protocol confusion"));
3111 crReturnV;
3112 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3113 logevent("X11 forwarding refused");
3114 } else {
3115 logevent("X11 forwarding enabled");
3116 ssh->X11_fwd_enabled = TRUE;
3117 }
3118 }
3119
3120 {
3121 char type;
3122 int n;
3123 int sport,dport,sserv,dserv;
3124 char sports[256], dports[256], saddr[256], host[256];
3125
3126 ssh->rportfwds = newtree234(ssh_rportcmp_ssh1);
3127 /* Add port forwardings. */
3128 ssh->portfwd_strptr = ssh->cfg.portfwd;
3129 while (*ssh->portfwd_strptr) {
3130 type = *ssh->portfwd_strptr++;
3131 saddr[0] = '\0';
3132 n = 0;
3133 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != '\t') {
3134 if (*ssh->portfwd_strptr == ':') {
3135 /*
3136 * We've seen a colon in the middle of the
3137 * source port number. This means that
3138 * everything we've seen until now is the
3139 * source _address_, so we'll move it into
3140 * saddr and start sports from the beginning
3141 * again.
3142 */
3143 ssh->portfwd_strptr++;
3144 sports[n] = '\0';
3145 strcpy(saddr, sports);
3146 n = 0;
3147 }
3148 if (n < 255) sports[n++] = *ssh->portfwd_strptr++;
3149 }
3150 sports[n] = 0;
3151 if (*ssh->portfwd_strptr == '\t')
3152 ssh->portfwd_strptr++;
3153 n = 0;
3154 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':') {
3155 if (n < 255) host[n++] = *ssh->portfwd_strptr++;
3156 }
3157 host[n] = 0;
3158 if (*ssh->portfwd_strptr == ':')
3159 ssh->portfwd_strptr++;
3160 n = 0;
3161 while (*ssh->portfwd_strptr) {
3162 if (n < 255) dports[n++] = *ssh->portfwd_strptr++;
3163 }
3164 dports[n] = 0;
3165 ssh->portfwd_strptr++;
3166 dport = atoi(dports);
3167 dserv = 0;
3168 if (dport == 0) {
3169 dserv = 1;
3170 dport = net_service_lookup(dports);
3171 if (!dport) {
3172 logeventf(ssh, "Service lookup failed for"
3173 " destination port \"%s\"", dports);
3174 }
3175 }
3176 sport = atoi(sports);
3177 sserv = 0;
3178 if (sport == 0) {
3179 sserv = 1;
3180 sport = net_service_lookup(sports);
3181 if (!sport) {
3182 logeventf(ssh, "Service lookup failed for source"
3183 " port \"%s\"", sports);
3184 }
3185 }
3186 if (sport && dport) {
3187 if (type == 'L') {
3188 pfd_addforward(host, dport, *saddr ? saddr : NULL,
3189 sport, ssh, &ssh->cfg);
3190 logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
3191 " forwarding to %s:%.*s%.*s%d%.*s",
3192 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
3193 (int)(*saddr?1:0), ":",
3194 (int)(sserv ? strlen(sports) : 0), sports,
3195 sserv, "(", sport, sserv, ")",
3196 host,
3197 (int)(dserv ? strlen(dports) : 0), dports,
3198 dserv, "(", dport, dserv, ")");
3199 } else {
3200 struct ssh_rportfwd *pf;
3201 pf = snew(struct ssh_rportfwd);
3202 strcpy(pf->dhost, host);
3203 pf->dport = dport;
3204 if (saddr) {
3205 logeventf(ssh,
3206 "SSH1 cannot handle source address spec \"%s:%d\"; ignoring",
3207 saddr, sport);
3208 }
3209 if (add234(ssh->rportfwds, pf) != pf) {
3210 logeventf(ssh,
3211 "Duplicate remote port forwarding to %s:%d",
3212 host, dport);
3213 sfree(pf);
3214 } else {
3215 logeventf(ssh, "Requesting remote port %.*s%.*s%d%.*s"
3216 " forward to %s:%.*s%.*s%d%.*s",
3217 (int)(sserv ? strlen(sports) : 0), sports,
3218 sserv, "(", sport, sserv, ")",
3219 host,
3220 (int)(dserv ? strlen(dports) : 0), dports,
3221 dserv, "(", dport, dserv, ")");
3222 send_packet(ssh, SSH1_CMSG_PORT_FORWARD_REQUEST,
3223 PKT_INT, sport,
3224 PKT_STR, host,
3225 PKT_INT, dport,
3226 PKT_END);
3227 do {
3228 crReturnV;
3229 } while (!ispkt);
3230 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3231 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3232 bombout(("Protocol confusion"));
3233 crReturnV;
3234 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3235 c_write_str(ssh, "Server refused port"
3236 " forwarding\r\n");
3237 }
3238 logevent("Remote port forwarding enabled");
3239 }
3240 }
3241 }
3242 }
3243 }
3244
3245 if (!ssh->cfg.nopty) {
3246 send_packet(ssh, SSH1_CMSG_REQUEST_PTY,
3247 PKT_STR, ssh->cfg.termtype,
3248 PKT_INT, ssh->term_height,
3249 PKT_INT, ssh->term_width,
3250 PKT_INT, 0, PKT_INT, 0, PKT_CHAR, 0, PKT_END);
3251 ssh->state = SSH_STATE_INTERMED;
3252 do {
3253 crReturnV;
3254 } while (!ispkt);
3255 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3256 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3257 bombout(("Protocol confusion"));
3258 crReturnV;
3259 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3260 c_write_str(ssh, "Server refused to allocate pty\r\n");
3261 ssh->editing = ssh->echoing = 1;
3262 }
3263 logevent("Allocated pty");
3264 } else {
3265 ssh->editing = ssh->echoing = 1;
3266 }
3267
3268 if (ssh->cfg.compression) {
3269 send_packet(ssh, SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END);
3270 do {
3271 crReturnV;
3272 } while (!ispkt);
3273 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3274 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3275 bombout(("Protocol confusion"));
3276 crReturnV;
3277 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3278 c_write_str(ssh, "Server refused to compress\r\n");
3279 }
3280 logevent("Started compression");
3281 ssh->v1_compressing = TRUE;
3282 ssh->cs_comp_ctx = zlib_compress_init();
3283 logevent("Initialised zlib (RFC1950) compression");
3284 ssh->sc_comp_ctx = zlib_decompress_init();
3285 logevent("Initialised zlib (RFC1950) decompression");
3286 }
3287
3288 /*
3289 * Start the shell or command.
3290 *
3291 * Special case: if the first-choice command is an SSH2
3292 * subsystem (hence not usable here) and the second choice
3293 * exists, we fall straight back to that.
3294 */
3295 {
3296 char *cmd = ssh->cfg.remote_cmd_ptr;
3297
3298 if (ssh->cfg.ssh_subsys && ssh->cfg.remote_cmd_ptr2) {
3299 cmd = ssh->cfg.remote_cmd_ptr2;
3300 ssh->fallback_cmd = TRUE;
3301 }
3302 if (*cmd)
3303 send_packet(ssh, SSH1_CMSG_EXEC_CMD, PKT_STR, cmd, PKT_END);
3304 else
3305 send_packet(ssh, SSH1_CMSG_EXEC_SHELL, PKT_END);
3306 logevent("Started session");
3307 }
3308
3309 ssh->state = SSH_STATE_SESSION;
3310 if (ssh->size_needed)
3311 ssh_size(ssh, ssh->term_width, ssh->term_height);
3312 if (ssh->eof_needed)
3313 ssh_special(ssh, TS_EOF);
3314
3315 if (ssh->ldisc)
3316 ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */
3317 ssh->send_ok = 1;
3318 ssh->channels = newtree234(ssh_channelcmp);
3319 while (1) {
3320 crReturnV;
3321 if (ispkt) {
3322 if (ssh->pktin.type == SSH1_SMSG_STDOUT_DATA ||
3323 ssh->pktin.type == SSH1_SMSG_STDERR_DATA) {
3324 long len = GET_32BIT(ssh->pktin.body);
3325 int bufsize =
3326 from_backend(ssh->frontend,
3327 ssh->pktin.type == SSH1_SMSG_STDERR_DATA,
3328 (char *)(ssh->pktin.body) + 4, len);
3329 if (!ssh->v1_stdout_throttling && bufsize > SSH1_BUFFER_LIMIT) {
3330 ssh->v1_stdout_throttling = 1;
3331 ssh1_throttle(ssh, +1);
3332 }
3333 } else if (ssh->pktin.type == SSH1_MSG_DISCONNECT) {
3334 ssh_closing((Plug)ssh, NULL, 0, 0);
3335 logevent("Received disconnect request");
3336 crReturnV;
3337 } else if (ssh->pktin.type == SSH1_SMSG_X11_OPEN) {
3338 /* Remote side is trying to open a channel to talk to our
3339 * X-Server. Give them back a local channel number. */
3340 struct ssh_channel *c;
3341
3342 logevent("Received X11 connect request");
3343 /* Refuse if X11 forwarding is disabled. */
3344 if (!ssh->X11_fwd_enabled) {
3345 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3346 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
3347 logevent("Rejected X11 connect request");
3348 } else {
3349 c = snew(struct ssh_channel);
3350 c->ssh = ssh;
3351
3352 if (x11_init(&c->u.x11.s, ssh->cfg.x11_display, c,
3353 ssh->x11auth, NULL, -1, &ssh->cfg) != NULL) {
3354 logevent("opening X11 forward connection failed");
3355 sfree(c);
3356 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3357 PKT_INT, GET_32BIT(ssh->pktin.body),
3358 PKT_END);
3359 } else {
3360 logevent
3361 ("opening X11 forward connection succeeded");
3362 c->remoteid = GET_32BIT(ssh->pktin.body);
3363 c->localid = alloc_channel_id(ssh);
3364 c->closes = 0;
3365 c->v.v1.throttling = 0;
3366 c->type = CHAN_X11; /* identify channel type */
3367 add234(ssh->channels, c);
3368 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3369 PKT_INT, c->remoteid, PKT_INT,
3370 c->localid, PKT_END);
3371 logevent("Opened X11 forward channel");
3372 }
3373 }
3374 } else if (ssh->pktin.type == SSH1_SMSG_AGENT_OPEN) {
3375 /* Remote side is trying to open a channel to talk to our
3376 * agent. Give them back a local channel number. */
3377 struct ssh_channel *c;
3378
3379 /* Refuse if agent forwarding is disabled. */
3380 if (!ssh->agentfwd_enabled) {
3381 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3382 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
3383 } else {
3384 c = snew(struct ssh_channel);
3385 c->ssh = ssh;
3386 c->remoteid = GET_32BIT(ssh->pktin.body);
3387 c->localid = alloc_channel_id(ssh);
3388 c->closes = 0;
3389 c->v.v1.throttling = 0;
3390 c->type = CHAN_AGENT; /* identify channel type */
3391 c->u.a.lensofar = 0;
3392 add234(ssh->channels, c);
3393 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3394 PKT_INT, c->remoteid, PKT_INT, c->localid,
3395 PKT_END);
3396 }
3397 } else if (ssh->pktin.type == SSH1_MSG_PORT_OPEN) {
3398 /* Remote side is trying to open a channel to talk to a
3399 * forwarded port. Give them back a local channel number. */
3400 struct ssh_channel *c;
3401 struct ssh_rportfwd pf;
3402 int hostsize, port;
3403 char host[256], buf[1024];
3404 char *p, *h, *e;
3405 c = snew(struct ssh_channel);
3406 c->ssh = ssh;
3407
3408 hostsize = GET_32BIT(ssh->pktin.body+4);
3409 for (h = host, p = (char *)(ssh->pktin.body+8);
3410 hostsize != 0; hostsize--) {
3411 if (h+1 < host+sizeof(host))
3412 *h++ = *p;
3413 p++;
3414 }
3415 *h = 0;
3416 port = GET_32BIT(p);
3417
3418 strcpy(pf.dhost, host);
3419 pf.dport = port;
3420
3421 if (find234(ssh->rportfwds, &pf, NULL) == NULL) {
3422 sprintf(buf, "Rejected remote port open request for %s:%d",
3423 host, port);
3424 logevent(buf);
3425 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3426 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
3427 } else {
3428 sprintf(buf, "Received remote port open request for %s:%d",
3429 host, port);
3430 logevent(buf);
3431 e = pfd_newconnect(&c->u.pfd.s, host, port, c, &ssh->cfg);
3432 if (e != NULL) {
3433 char buf[256];
3434 sprintf(buf, "Port open failed: %s", e);
3435 logevent(buf);
3436 sfree(c);
3437 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3438 PKT_INT, GET_32BIT(ssh->pktin.body),
3439 PKT_END);
3440 } else {
3441 c->remoteid = GET_32BIT(ssh->pktin.body);
3442 c->localid = alloc_channel_id(ssh);
3443 c->closes = 0;
3444 c->v.v1.throttling = 0;
3445 c->type = CHAN_SOCKDATA; /* identify channel type */
3446 add234(ssh->channels, c);
3447 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3448 PKT_INT, c->remoteid, PKT_INT,
3449 c->localid, PKT_END);
3450 logevent("Forwarded port opened successfully");
3451 }
3452 }
3453
3454 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_OPEN_CONFIRMATION) {
3455 unsigned int remoteid = GET_32BIT(ssh->pktin.body);
3456 unsigned int localid = GET_32BIT(ssh->pktin.body+4);
3457 struct ssh_channel *c;
3458
3459 c = find234(ssh->channels, &remoteid, ssh_channelfind);
3460 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
3461 c->remoteid = localid;
3462 c->type = CHAN_SOCKDATA;
3463 c->v.v1.throttling = 0;
3464 pfd_confirm(c->u.pfd.s);
3465 }
3466
3467 if (c && c->closes) {
3468 /*
3469 * We have a pending close on this channel,
3470 * which we decided on before the server acked
3471 * the channel open. So now we know the
3472 * remoteid, we can close it again.
3473 */
3474 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE,
3475 PKT_INT, c->remoteid, PKT_END);
3476 }
3477
3478 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_OPEN_FAILURE) {
3479 unsigned int remoteid = GET_32BIT(ssh->pktin.body);
3480 struct ssh_channel *c;
3481
3482 c = find234(ssh->channels, &remoteid, ssh_channelfind);
3483 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
3484 logevent("Forwarded connection refused by server");
3485 pfd_close(c->u.pfd.s);
3486 del234(ssh->channels, c);
3487 sfree(c);
3488 }
3489
3490 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ||
3491 ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION) {
3492 /* Remote side closes a channel. */
3493 unsigned i = GET_32BIT(ssh->pktin.body);
3494 struct ssh_channel *c;
3495 c = find234(ssh->channels, &i, ssh_channelfind);
3496 if (c && ((int)c->remoteid) != -1) {
3497 int closetype;
3498 closetype =
3499 (ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ? 1 : 2);
3500
3501 if ((c->closes == 0) && (c->type == CHAN_X11)) {
3502 logevent("Forwarded X11 connection terminated");
3503 assert(c->u.x11.s != NULL);
3504 x11_close(c->u.x11.s);
3505 c->u.x11.s = NULL;
3506 }
3507 if ((c->closes == 0) && (c->type == CHAN_SOCKDATA)) {
3508 logevent("Forwarded port closed");
3509 assert(c->u.pfd.s != NULL);
3510 pfd_close(c->u.pfd.s);
3511 c->u.pfd.s = NULL;
3512 }
3513
3514 c->closes |= (closetype << 2); /* seen this message */
3515 if (!(c->closes & closetype)) {
3516 send_packet(ssh, ssh->pktin.type, PKT_INT, c->remoteid,
3517 PKT_END);
3518 c->closes |= closetype; /* sent it too */
3519 }
3520
3521 if (c->closes == 15) {
3522 del234(ssh->channels, c);
3523 sfree(c);
3524 }
3525 } else {
3526 bombout(("Received CHANNEL_CLOSE%s for %s channel %d\n",
3527 ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ? "" :
3528 "_CONFIRMATION", c ? "half-open" : "nonexistent",
3529 i));
3530 }
3531 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_DATA) {
3532 /* Data sent down one of our channels. */
3533 int i = GET_32BIT(ssh->pktin.body);
3534 int len = GET_32BIT(ssh->pktin.body + 4);
3535 unsigned char *p = ssh->pktin.body + 8;
3536 struct ssh_channel *c;
3537 c = find234(ssh->channels, &i, ssh_channelfind);
3538 if (c) {
3539 int bufsize;
3540 switch (c->type) {
3541 case CHAN_X11:
3542 bufsize = x11_send(c->u.x11.s, (char *)p, len);
3543 break;
3544 case CHAN_SOCKDATA:
3545 bufsize = pfd_send(c->u.pfd.s, (char *)p, len);
3546 break;
3547 case CHAN_AGENT:
3548 /* Data for an agent message. Buffer it. */
3549 while (len > 0) {
3550 if (c->u.a.lensofar < 4) {
3551 int l = min(4 - c->u.a.lensofar, len);
3552 memcpy(c->u.a.msglen + c->u.a.lensofar, p,
3553 l);
3554 p += l;
3555 len -= l;
3556 c->u.a.lensofar += l;
3557 }
3558 if (c->u.a.lensofar == 4) {
3559 c->u.a.totallen =
3560 4 + GET_32BIT(c->u.a.msglen);
3561 c->u.a.message = snewn(c->u.a.totallen,
3562 unsigned char);
3563 memcpy(c->u.a.message, c->u.a.msglen, 4);
3564 }
3565 if (c->u.a.lensofar >= 4 && len > 0) {
3566 int l =
3567 min(c->u.a.totallen - c->u.a.lensofar,
3568 len);
3569 memcpy(c->u.a.message + c->u.a.lensofar, p,
3570 l);
3571 p += l;
3572 len -= l;
3573 c->u.a.lensofar += l;
3574 }
3575 if (c->u.a.lensofar == c->u.a.totallen) {
3576 void *reply, *sentreply;
3577 int replylen;
3578 agent_query(c->u.a.message,
3579 c->u.a.totallen, &reply,
3580 &replylen);
3581 if (reply)
3582 sentreply = reply;
3583 else {
3584 /* Fake SSH_AGENT_FAILURE. */
3585 sentreply = "\0\0\0\1\5";
3586 replylen = 5;
3587 }
3588 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
3589 PKT_INT, c->remoteid,
3590 PKT_INT, replylen,
3591 PKT_DATA, sentreply, replylen,
3592 PKT_END);
3593 if (reply)
3594 sfree(reply);
3595 sfree(c->u.a.message);
3596 c->u.a.lensofar = 0;
3597 }
3598 }
3599 bufsize = 0; /* agent channels never back up */
3600 break;
3601 }
3602 if (!c->v.v1.throttling && bufsize > SSH1_BUFFER_LIMIT) {
3603 c->v.v1.throttling = 1;
3604 ssh1_throttle(ssh, +1);
3605 }
3606 }
3607 } else if (ssh->pktin.type == SSH1_SMSG_SUCCESS) {
3608 /* may be from EXEC_SHELL on some servers */
3609 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3610 /* may be from EXEC_SHELL on some servers
3611 * if no pty is available or in other odd cases. Ignore */
3612 } else if (ssh->pktin.type == SSH1_SMSG_EXIT_STATUS) {
3613 char buf[100];
3614 ssh->exitcode = GET_32BIT(ssh->pktin.body);
3615 sprintf(buf, "Server sent command exit status %d",
3616 ssh->exitcode);
3617 logevent(buf);
3618 send_packet(ssh, SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
3619 /*
3620 * In case `helpful' firewalls or proxies tack
3621 * extra human-readable text on the end of the
3622 * session which we might mistake for another
3623 * encrypted packet, we close the session once
3624 * we've sent EXIT_CONFIRMATION.
3625 */
3626 ssh_closing((Plug)ssh, NULL, 0, 0);
3627 crReturnV;
3628 } else {
3629 bombout(("Strange packet received: type %d", ssh->pktin.type));
3630 crReturnV;
3631 }
3632 } else {
3633 while (inlen > 0) {
3634 int len = min(inlen, 512);
3635 send_packet(ssh, SSH1_CMSG_STDIN_DATA,
3636 PKT_INT, len, PKT_DATA, in, len, PKT_END);
3637 in += len;
3638 inlen -= len;
3639 }
3640 }
3641 }
3642
3643 crFinishV;
3644 }
3645
3646 /*
3647 * Utility routine for decoding comma-separated strings in KEXINIT.
3648 */
3649 static int in_commasep_string(char *needle, char *haystack, int haylen)
3650 {
3651 int needlen;
3652 if (!needle || !haystack) /* protect against null pointers */
3653 return 0;
3654 needlen = strlen(needle);
3655 while (1) {
3656 /*
3657 * Is it at the start of the string?
3658 */
3659 if (haylen >= needlen && /* haystack is long enough */
3660 !memcmp(needle, haystack, needlen) && /* initial match */
3661 (haylen == needlen || haystack[needlen] == ',')
3662 /* either , or EOS follows */
3663 )
3664 return 1;
3665 /*
3666 * If not, search for the next comma and resume after that.
3667 * If no comma found, terminate.
3668 */
3669 while (haylen > 0 && *haystack != ',')
3670 haylen--, haystack++;
3671 if (haylen == 0)
3672 return 0;
3673 haylen--, haystack++; /* skip over comma itself */
3674 }
3675 }
3676
3677 /*
3678 * SSH2 key creation method.
3679 */
3680 static void ssh2_mkkey(Ssh ssh, Bignum K, unsigned char *H,
3681 unsigned char *sessid, char chr,
3682 unsigned char *keyspace)
3683 {
3684 SHA_State s;
3685 /* First 20 bytes. */
3686 SHA_Init(&s);
3687 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
3688 sha_mpint(&s, K);
3689 SHA_Bytes(&s, H, 20);
3690 SHA_Bytes(&s, &chr, 1);
3691 SHA_Bytes(&s, sessid, 20);
3692 SHA_Final(&s, keyspace);
3693 /* Next 20 bytes. */
3694 SHA_Init(&s);
3695 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
3696 sha_mpint(&s, K);
3697 SHA_Bytes(&s, H, 20);
3698 SHA_Bytes(&s, keyspace, 20);
3699 SHA_Final(&s, keyspace + 20);
3700 }
3701
3702 /*
3703 * Handle the SSH2 transport layer.
3704 */
3705 static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
3706 {
3707 struct do_ssh2_transport_state {
3708 int nbits, pbits, warn;
3709 Bignum p, g, e, f, K;
3710 int kex_init_value, kex_reply_value;
3711 const struct ssh_mac **maclist;
3712 int nmacs;
3713 const struct ssh2_cipher *cscipher_tobe;
3714 const struct ssh2_cipher *sccipher_tobe;
3715 const struct ssh_mac *csmac_tobe;
3716 const struct ssh_mac *scmac_tobe;
3717 const struct ssh_compress *cscomp_tobe;
3718 const struct ssh_compress *sccomp_tobe;
3719 char *hostkeydata, *sigdata, *keystr, *fingerprint;
3720 int hostkeylen, siglen;
3721 void *hkey; /* actual host key */
3722 unsigned char exchange_hash[20];
3723 int n_preferred_ciphers;
3724 const struct ssh2_ciphers *preferred_ciphers[CIPHER_MAX];
3725 const struct ssh_compress *preferred_comp;
3726 int first_kex;
3727 };
3728 crState(do_ssh2_transport_state);
3729
3730 crBegin(ssh->do_ssh2_transport_crstate);
3731
3732 s->cscipher_tobe = s->sccipher_tobe = NULL;
3733 s->csmac_tobe = s->scmac_tobe = NULL;
3734 s->cscomp_tobe = s->sccomp_tobe = NULL;
3735
3736 random_init();
3737 s->first_kex = 1;
3738
3739 {
3740 int i;
3741 /*
3742 * Set up the preferred ciphers. (NULL => warn below here)
3743 */
3744 s->n_preferred_ciphers = 0;
3745 for (i = 0; i < CIPHER_MAX; i++) {
3746 switch (ssh->cfg.ssh_cipherlist[i]) {
3747 case CIPHER_BLOWFISH:
3748 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_blowfish;
3749 break;
3750 case CIPHER_DES:
3751 if (ssh->cfg.ssh2_des_cbc) {
3752 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_des;
3753 }
3754 break;
3755 case CIPHER_3DES:
3756 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_3des;
3757 break;
3758 case CIPHER_AES:
3759 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_aes;
3760 break;
3761 case CIPHER_WARN:
3762 /* Flag for later. Don't bother if it's the last in
3763 * the list. */
3764 if (i < CIPHER_MAX - 1) {
3765 s->preferred_ciphers[s->n_preferred_ciphers++] = NULL;
3766 }
3767 break;
3768 }
3769 }
3770 }
3771
3772 /*
3773 * Set up preferred compression.
3774 */
3775 if (ssh->cfg.compression)
3776 s->preferred_comp = &ssh_zlib;
3777 else
3778 s->preferred_comp = &ssh_comp_none;
3779
3780 /*
3781 * Be prepared to work around the buggy MAC problem.
3782 */
3783 if (ssh->remote_bugs & BUG_SSH2_HMAC)
3784 s->maclist = buggymacs, s->nmacs = lenof(buggymacs);
3785 else
3786 s->maclist = macs, s->nmacs = lenof(macs);
3787
3788 begin_key_exchange:
3789 {
3790 int i, j, cipherstr_started;
3791
3792 /*
3793 * Construct and send our key exchange packet.
3794 */
3795 ssh2_pkt_init(ssh, SSH2_MSG_KEXINIT);
3796 for (i = 0; i < 16; i++)
3797 ssh2_pkt_addbyte(ssh, (unsigned char) random_byte());
3798 /* List key exchange algorithms. */
3799 ssh2_pkt_addstring_start(ssh);
3800 for (i = 0; i < lenof(kex_algs); i++) {
3801 if (kex_algs[i] == &ssh_diffiehellman_gex &&
3802 (ssh->remote_bugs & BUG_SSH2_DH_GEX))
3803 continue;
3804 ssh2_pkt_addstring_str(ssh, kex_algs[i]->name);
3805 if (i < lenof(kex_algs) - 1)
3806 ssh2_pkt_addstring_str(ssh, ",");
3807 }
3808 /* List server host key algorithms. */
3809 ssh2_pkt_addstring_start(ssh);
3810 for (i = 0; i < lenof(hostkey_algs); i++) {
3811 ssh2_pkt_addstring_str(ssh, hostkey_algs[i]->name);
3812 if (i < lenof(hostkey_algs) - 1)
3813 ssh2_pkt_addstring_str(ssh, ",");
3814 }
3815 /* List client->server encryption algorithms. */
3816 ssh2_pkt_addstring_start(ssh);
3817 cipherstr_started = 0;
3818 for (i = 0; i < s->n_preferred_ciphers; i++) {
3819 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3820 if (!c) continue; /* warning flag */
3821 for (j = 0; j < c->nciphers; j++) {
3822 if (cipherstr_started)
3823 ssh2_pkt_addstring_str(ssh, ",");
3824 ssh2_pkt_addstring_str(ssh, c->list[j]->name);
3825 cipherstr_started = 1;
3826 }
3827 }
3828 /* List server->client encryption algorithms. */
3829 ssh2_pkt_addstring_start(ssh);
3830 cipherstr_started = 0;
3831 for (i = 0; i < s->n_preferred_ciphers; i++) {
3832 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3833 if (!c) continue; /* warning flag */
3834 for (j = 0; j < c->nciphers; j++) {
3835 if (cipherstr_started)
3836 ssh2_pkt_addstring_str(ssh, ",");
3837 ssh2_pkt_addstring_str(ssh, c->list[j]->name);
3838 cipherstr_started = 1;
3839 }
3840 }
3841 /* List client->server MAC algorithms. */
3842 ssh2_pkt_addstring_start(ssh);
3843 for (i = 0; i < s->nmacs; i++) {
3844 ssh2_pkt_addstring_str(ssh, s->maclist[i]->name);
3845 if (i < s->nmacs - 1)
3846 ssh2_pkt_addstring_str(ssh, ",");
3847 }
3848 /* List server->client MAC algorithms. */
3849 ssh2_pkt_addstring_start(ssh);
3850 for (i = 0; i < s->nmacs; i++) {
3851 ssh2_pkt_addstring_str(ssh, s->maclist[i]->name);
3852 if (i < s->nmacs - 1)
3853 ssh2_pkt_addstring_str(ssh, ",");
3854 }
3855 /* List client->server compression algorithms. */
3856 ssh2_pkt_addstring_start(ssh);
3857 for (i = 0; i < lenof(compressions) + 1; i++) {
3858 const struct ssh_compress *c =
3859 i == 0 ? s->preferred_comp : compressions[i - 1];
3860 ssh2_pkt_addstring_str(ssh, c->name);
3861 if (i < lenof(compressions))
3862 ssh2_pkt_addstring_str(ssh, ",");
3863 }
3864 /* List server->client compression algorithms. */
3865 ssh2_pkt_addstring_start(ssh);
3866 for (i = 0; i < lenof(compressions) + 1; i++) {
3867 const struct ssh_compress *c =
3868 i == 0 ? s->preferred_comp : compressions[i - 1];
3869 ssh2_pkt_addstring_str(ssh, c->name);
3870 if (i < lenof(compressions))
3871 ssh2_pkt_addstring_str(ssh, ",");
3872 }
3873 /* List client->server languages. Empty list. */
3874 ssh2_pkt_addstring_start(ssh);
3875 /* List server->client languages. Empty list. */
3876 ssh2_pkt_addstring_start(ssh);
3877 /* First KEX packet does _not_ follow, because we're not that brave. */
3878 ssh2_pkt_addbool(ssh, FALSE);
3879 /* Reserved. */
3880 ssh2_pkt_adduint32(ssh, 0);
3881 }
3882
3883 ssh->exhash = ssh->exhashbase;
3884 sha_string(&ssh->exhash, ssh->pktout.data + 5, ssh->pktout.length - 5);
3885
3886 ssh2_pkt_send(ssh);
3887
3888 if (!ispkt)
3889 crWaitUntil(ispkt);
3890 if (ssh->pktin.length > 5)
3891 sha_string(&ssh->exhash, ssh->pktin.data + 5, ssh->pktin.length - 5);
3892
3893 /*
3894 * Now examine the other side's KEXINIT to see what we're up
3895 * to.
3896 */
3897 {
3898 char *str;
3899 int i, j, len;
3900
3901 if (ssh->pktin.type != SSH2_MSG_KEXINIT) {
3902 bombout(("expected key exchange packet from server"));
3903 crReturn(0);
3904 }
3905 ssh->kex = NULL;
3906 ssh->hostkey = NULL;
3907 s->cscipher_tobe = NULL;
3908 s->sccipher_tobe = NULL;
3909 s->csmac_tobe = NULL;
3910 s->scmac_tobe = NULL;
3911 s->cscomp_tobe = NULL;
3912 s->sccomp_tobe = NULL;
3913 ssh->pktin.savedpos += 16; /* skip garbage cookie */
3914 ssh2_pkt_getstring(ssh, &str, &len); /* key exchange algorithms */
3915 for (i = 0; i < lenof(kex_algs); i++) {
3916 if (kex_algs[i] == &ssh_diffiehellman_gex &&
3917 (ssh->remote_bugs & BUG_SSH2_DH_GEX))
3918 continue;
3919 if (in_commasep_string(kex_algs[i]->name, str, len)) {
3920 ssh->kex = kex_algs[i];
3921 break;
3922 }
3923 }
3924 ssh2_pkt_getstring(ssh, &str, &len); /* host key algorithms */
3925 for (i = 0; i < lenof(hostkey_algs); i++) {
3926 if (in_commasep_string(hostkey_algs[i]->name, str, len)) {
3927 ssh->hostkey = hostkey_algs[i];
3928 break;
3929 }
3930 }
3931 ssh2_pkt_getstring(ssh, &str, &len); /* client->server cipher */
3932 s->warn = 0;
3933 for (i = 0; i < s->n_preferred_ciphers; i++) {
3934 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3935 if (!c) {
3936 s->warn = 1;
3937 } else {
3938 for (j = 0; j < c->nciphers; j++) {
3939 if (in_commasep_string(c->list[j]->name, str, len)) {
3940 s->cscipher_tobe = c->list[j];
3941 break;
3942 }
3943 }
3944 }
3945 if (s->cscipher_tobe) {
3946 if (s->warn)
3947 askcipher(ssh->frontend, s->cscipher_tobe->name, 1);
3948 break;
3949 }
3950 }
3951 if (!s->cscipher_tobe) {
3952 bombout(("Couldn't agree a client-to-server cipher (available: %s)",
3953 str ? str : "(null)"));
3954 crReturn(0);
3955 }
3956
3957 ssh2_pkt_getstring(ssh, &str, &len); /* server->client cipher */
3958 s->warn = 0;
3959 for (i = 0; i < s->n_preferred_ciphers; i++) {
3960 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3961 if (!c) {
3962 s->warn = 1;
3963 } else {
3964 for (j = 0; j < c->nciphers; j++) {
3965 if (in_commasep_string(c->list[j]->name, str, len)) {
3966 s->sccipher_tobe = c->list[j];
3967 break;
3968 }
3969 }
3970 }
3971 if (s->sccipher_tobe) {
3972 if (s->warn)
3973 askcipher(ssh->frontend, s->sccipher_tobe->name, 2);
3974 break;
3975 }
3976 }
3977 if (!s->sccipher_tobe) {
3978 bombout(("Couldn't agree a server-to-client cipher (available: %s)",
3979 str ? str : "(null)"));
3980 crReturn(0);
3981 }
3982
3983 ssh2_pkt_getstring(ssh, &str, &len); /* client->server mac */
3984 for (i = 0; i < s->nmacs; i++) {
3985 if (in_commasep_string(s->maclist[i]->name, str, len)) {
3986 s->csmac_tobe = s->maclist[i];
3987 break;
3988 }
3989 }
3990 ssh2_pkt_getstring(ssh, &str, &len); /* server->client mac */
3991 for (i = 0; i < s->nmacs; i++) {
3992 if (in_commasep_string(s->maclist[i]->name, str, len)) {
3993 s->scmac_tobe = s->maclist[i];
3994 break;
3995 }
3996 }
3997 ssh2_pkt_getstring(ssh, &str, &len); /* client->server compression */
3998 for (i = 0; i < lenof(compressions) + 1; i++) {
3999 const struct ssh_compress *c =
4000 i == 0 ? s->preferred_comp : compressions[i - 1];
4001 if (in_commasep_string(c->name, str, len)) {
4002 s->cscomp_tobe = c;
4003 break;
4004 }
4005 }
4006 ssh2_pkt_getstring(ssh, &str, &len); /* server->client compression */
4007 for (i = 0; i < lenof(compressions) + 1; i++) {
4008 const struct ssh_compress *c =
4009 i == 0 ? s->preferred_comp : compressions[i - 1];
4010 if (in_commasep_string(c->name, str, len)) {
4011 s->sccomp_tobe = c;
4012 break;
4013 }
4014 }
4015 }
4016
4017 /*
4018 * Work out the number of bits of key we will need from the key
4019 * exchange. We start with the maximum key length of either
4020 * cipher...
4021 */
4022 {
4023 int csbits, scbits;
4024
4025 csbits = s->cscipher_tobe->keylen;
4026 scbits = s->sccipher_tobe->keylen;
4027 s->nbits = (csbits > scbits ? csbits : scbits);
4028 }
4029 /* The keys only have 160-bit entropy, since they're based on
4030 * a SHA-1 hash. So cap the key size at 160 bits. */
4031 if (s->nbits > 160)
4032 s->nbits = 160;
4033
4034 /*
4035 * If we're doing Diffie-Hellman group exchange, start by
4036 * requesting a group.
4037 */
4038 if (ssh->kex == &ssh_diffiehellman_gex) {
4039 logevent("Doing Diffie-Hellman group exchange");
4040 ssh->pkt_ctx |= SSH2_PKTCTX_DHGEX;
4041 /*
4042 * Work out how big a DH group we will need to allow that
4043 * much data.
4044 */
4045 s->pbits = 512 << ((s->nbits - 1) / 64);
4046 ssh2_pkt_init(ssh, SSH2_MSG_KEX_DH_GEX_REQUEST);
4047 ssh2_pkt_adduint32(ssh, s->pbits);
4048 ssh2_pkt_send(ssh);
4049
4050 crWaitUntil(ispkt);
4051 if (ssh->pktin.type != SSH2_MSG_KEX_DH_GEX_GROUP) {
4052 bombout(("expected key exchange group packet from server"));
4053 crReturn(0);
4054 }
4055 s->p = ssh2_pkt_getmp(ssh);
4056 s->g = ssh2_pkt_getmp(ssh);
4057 ssh->kex_ctx = dh_setup_group(s->p, s->g);
4058 s->kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT;
4059 s->kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY;
4060 } else {
4061 ssh->pkt_ctx |= SSH2_PKTCTX_DHGROUP1;
4062 ssh->kex_ctx = dh_setup_group1();
4063 s->kex_init_value = SSH2_MSG_KEXDH_INIT;
4064 s->kex_reply_value = SSH2_MSG_KEXDH_REPLY;
4065 }
4066
4067 logevent("Doing Diffie-Hellman key exchange");
4068 /*
4069 * Now generate and send e for Diffie-Hellman.
4070 */
4071 s->e = dh_create_e(ssh->kex_ctx, s->nbits * 2);
4072 ssh2_pkt_init(ssh, s->kex_init_value);
4073 ssh2_pkt_addmp(ssh, s->e);
4074 ssh2_pkt_send(ssh);
4075
4076 crWaitUntil(ispkt);
4077 if (ssh->pktin.type != s->kex_reply_value) {
4078 bombout(("expected key exchange reply packet from server"));
4079 crReturn(0);
4080 }
4081 ssh2_pkt_getstring(ssh, &s->hostkeydata, &s->hostkeylen);
4082 s->f = ssh2_pkt_getmp(ssh);
4083 ssh2_pkt_getstring(ssh, &s->sigdata, &s->siglen);
4084
4085 s->K = dh_find_K(ssh->kex_ctx, s->f);
4086
4087 sha_string(&ssh->exhash, s->hostkeydata, s->hostkeylen);
4088 if (ssh->kex == &ssh_diffiehellman_gex) {
4089 sha_uint32(&ssh->exhash, s->pbits);
4090 sha_mpint(&ssh->exhash, s->p);
4091 sha_mpint(&ssh->exhash, s->g);
4092 }
4093 sha_mpint(&ssh->exhash, s->e);
4094 sha_mpint(&ssh->exhash, s->f);
4095 sha_mpint(&ssh->exhash, s->K);
4096 SHA_Final(&ssh->exhash, s->exchange_hash);
4097
4098 dh_cleanup(ssh->kex_ctx);
4099 ssh->kex_ctx = NULL;
4100
4101 #if 0
4102 debug(("Exchange hash is:\n"));
4103 dmemdump(s->exchange_hash, 20);
4104 #endif
4105
4106 s->hkey = ssh->hostkey->newkey(s->hostkeydata, s->hostkeylen);
4107 if (!s->hkey ||
4108 !ssh->hostkey->verifysig(s->hkey, s->sigdata, s->siglen,
4109 (char *)s->exchange_hash, 20)) {
4110 bombout(("Server's host key did not match the signature supplied"));
4111 crReturn(0);
4112 }
4113
4114 /*
4115 * Authenticate remote host: verify host key. (We've already
4116 * checked the signature of the exchange hash.)
4117 */
4118 s->keystr = ssh->hostkey->fmtkey(s->hkey);
4119 s->fingerprint = ssh->hostkey->fingerprint(s->hkey);
4120 verify_ssh_host_key(ssh->frontend,
4121 ssh->savedhost, ssh->savedport, ssh->hostkey->keytype,
4122 s->keystr, s->fingerprint);
4123 if (s->first_kex) { /* don't bother logging this in rekeys */
4124 logevent("Host key fingerprint is:");
4125 logevent(s->fingerprint);
4126 }
4127 sfree(s->fingerprint);
4128 sfree(s->keystr);
4129 ssh->hostkey->freekey(s->hkey);
4130
4131 /*
4132 * Send SSH2_MSG_NEWKEYS.
4133 */
4134 ssh2_pkt_init(ssh, SSH2_MSG_NEWKEYS);
4135 ssh2_pkt_send(ssh);
4136
4137 /*
4138 * Expect SSH2_MSG_NEWKEYS from server.
4139 */
4140 crWaitUntil(ispkt);
4141 if (ssh->pktin.type != SSH2_MSG_NEWKEYS) {
4142 bombout(("expected new-keys packet from server"));
4143 crReturn(0);
4144 }
4145
4146 /*
4147 * Create and initialise session keys.
4148 */
4149 if (ssh->cs_cipher_ctx)
4150 ssh->cscipher->free_context(ssh->cs_cipher_ctx);
4151 ssh->cscipher = s->cscipher_tobe;
4152 ssh->cs_cipher_ctx = ssh->cscipher->make_context();
4153
4154 if (ssh->sc_cipher_ctx)
4155 ssh->sccipher->free_context(ssh->sc_cipher_ctx);
4156 ssh->sccipher = s->sccipher_tobe;
4157 ssh->sc_cipher_ctx = ssh->sccipher->make_context();
4158
4159 if (ssh->cs_mac_ctx)
4160 ssh->csmac->free_context(ssh->cs_mac_ctx);
4161 ssh->csmac = s->csmac_tobe;
4162 ssh->cs_mac_ctx = ssh->csmac->make_context();
4163
4164 if (ssh->sc_mac_ctx)
4165 ssh->scmac->free_context(ssh->sc_mac_ctx);
4166 ssh->scmac = s->scmac_tobe;
4167 ssh->sc_mac_ctx = ssh->scmac->make_context();
4168
4169 if (ssh->cs_comp_ctx)
4170 ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
4171 ssh->cscomp = s->cscomp_tobe;
4172 ssh->cs_comp_ctx = ssh->cscomp->compress_init();
4173
4174 if (ssh->sc_comp_ctx)
4175 ssh->sccomp->decompress_cleanup(ssh->sc_comp_ctx);
4176 ssh->sccomp = s->sccomp_tobe;
4177 ssh->sc_comp_ctx = ssh->sccomp->decompress_init();
4178
4179 /*
4180 * Set IVs after keys. Here we use the exchange hash from the
4181 * _first_ key exchange.
4182 */
4183 {
4184 unsigned char keyspace[40];
4185 if (s->first_kex)
4186 memcpy(ssh->v2_session_id, s->exchange_hash,
4187 sizeof(s->exchange_hash));
4188 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'C',keyspace);
4189 ssh->cscipher->setkey(ssh->cs_cipher_ctx, keyspace);
4190 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'D',keyspace);
4191 ssh->sccipher->setkey(ssh->sc_cipher_ctx, keyspace);
4192 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'A',keyspace);
4193 ssh->cscipher->setiv(ssh->cs_cipher_ctx, keyspace);
4194 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'B',keyspace);
4195 ssh->sccipher->setiv(ssh->sc_cipher_ctx, keyspace);
4196 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'E',keyspace);
4197 ssh->csmac->setkey(ssh->cs_mac_ctx, keyspace);
4198 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'F',keyspace);
4199 ssh->scmac->setkey(ssh->sc_mac_ctx, keyspace);
4200 }
4201 logeventf(ssh, "Initialised %.200s client->server encryption",
4202 ssh->cscipher->text_name);
4203 logeventf(ssh, "Initialised %.200s server->client encryption",
4204 ssh->sccipher->text_name);
4205 if (ssh->cscomp->text_name)
4206 logeventf(ssh, "Initialised %s compression",
4207 ssh->cscomp->text_name);
4208 if (ssh->sccomp->text_name)
4209 logeventf(ssh, "Initialised %s decompression",
4210 ssh->sccomp->text_name);
4211
4212 /*
4213 * If this is the first key exchange phase, we must pass the
4214 * SSH2_MSG_NEWKEYS packet to the next layer, not because it
4215 * wants to see it but because it will need time to initialise
4216 * itself before it sees an actual packet. In subsequent key
4217 * exchange phases, we don't pass SSH2_MSG_NEWKEYS on, because
4218 * it would only confuse the layer above.
4219 */
4220 if (!s->first_kex) {
4221 crReturn(0);
4222 }
4223 s->first_kex = 0;
4224
4225 /*
4226 * Now we're encrypting. Begin returning 1 to the protocol main
4227 * function so that other things can run on top of the
4228 * transport. If we ever see a KEXINIT, we must go back to the
4229 * start.
4230 */
4231 while (!(ispkt && ssh->pktin.type == SSH2_MSG_KEXINIT)) {
4232 crReturn(1);
4233 }
4234 logevent("Server initiated key re-exchange");
4235 goto begin_key_exchange;
4236
4237 crFinish(1);
4238 }
4239
4240 /*
4241 * Add data to an SSH2 channel output buffer.
4242 */
4243 static void ssh2_add_channel_data(struct ssh_channel *c, char *buf,
4244 int len)
4245 {
4246 bufchain_add(&c->v.v2.outbuffer, buf, len);
4247 }
4248
4249 /*
4250 * Attempt to send data on an SSH2 channel.
4251 */
4252 static int ssh2_try_send(struct ssh_channel *c)
4253 {
4254 Ssh ssh = c->ssh;
4255
4256 while (c->v.v2.remwindow > 0 && bufchain_size(&c->v.v2.outbuffer) > 0) {
4257 int len;
4258 void *data;
4259 bufchain_prefix(&c->v.v2.outbuffer, &data, &len);
4260 if ((unsigned)len > c->v.v2.remwindow)
4261 len = c->v.v2.remwindow;
4262 if ((unsigned)len > c->v.v2.remmaxpkt)
4263 len = c->v.v2.remmaxpkt;
4264 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_DATA);
4265 ssh2_pkt_adduint32(ssh, c->remoteid);
4266 ssh2_pkt_addstring_start(ssh);
4267 ssh2_pkt_addstring_data(ssh, data, len);
4268 ssh2_pkt_send(ssh);
4269 bufchain_consume(&c->v.v2.outbuffer, len);
4270 c->v.v2.remwindow -= len;
4271 }
4272
4273 /*
4274 * After having sent as much data as we can, return the amount
4275 * still buffered.
4276 */
4277 return bufchain_size(&c->v.v2.outbuffer);
4278 }
4279
4280 /*
4281 * Potentially enlarge the window on an SSH2 channel.
4282 */
4283 static void ssh2_set_window(struct ssh_channel *c, unsigned newwin)
4284 {
4285 Ssh ssh = c->ssh;
4286
4287 /*
4288 * Never send WINDOW_ADJUST for a channel that the remote side
4289 * already thinks it's closed; there's no point, since it won't
4290 * be sending any more data anyway.
4291 */
4292 if (c->closes != 0)
4293 return;
4294
4295 if (newwin > c->v.v2.locwindow) {
4296 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST);
4297 ssh2_pkt_adduint32(ssh, c->remoteid);
4298 ssh2_pkt_adduint32(ssh, newwin - c->v.v2.locwindow);
4299 ssh2_pkt_send(ssh);
4300 c->v.v2.locwindow = newwin;
4301 }
4302 }
4303
4304 /*
4305 * Handle the SSH2 userauth and connection layers.
4306 */
4307 static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
4308 {
4309 struct do_ssh2_authconn_state {
4310 enum {
4311 AUTH_INVALID, AUTH_PUBLICKEY_AGENT, AUTH_PUBLICKEY_FILE,
4312 AUTH_PASSWORD,
4313 AUTH_KEYBOARD_INTERACTIVE
4314 } method;
4315 enum {
4316 AUTH_TYPE_NONE,
4317 AUTH_TYPE_PUBLICKEY,
4318 AUTH_TYPE_PUBLICKEY_OFFER_LOUD,
4319 AUTH_TYPE_PUBLICKEY_OFFER_QUIET,
4320 AUTH_TYPE_PASSWORD,
4321 AUTH_TYPE_KEYBOARD_INTERACTIVE,
4322 AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET
4323 } type;
4324 int gotit, need_pw, can_pubkey, can_passwd, can_keyb_inter;
4325 int tried_pubkey_config, tried_agent, tried_keyb_inter;
4326 int kbd_inter_running;
4327 int we_are_in;
4328 int num_prompts, curr_prompt, echo;
4329 char username[100];
4330 int got_username;
4331 char pwprompt[200];
4332 char password[100];
4333 void *publickey_blob;
4334 int publickey_bloblen;
4335 unsigned char request[5], *response, *p;
4336 int responselen;
4337 int keyi, nkeys;
4338 int authed;
4339 char *pkblob, *alg, *commentp;
4340 int pklen, alglen, commentlen;
4341 int siglen, retlen, len;
4342 char *q, *agentreq, *ret;
4343 int try_send;
4344 };
4345 crState(do_ssh2_authconn_state);
4346
4347 crBegin(ssh->do_ssh2_authconn_crstate);
4348
4349 /*
4350 * Request userauth protocol, and await a response to it.
4351 */
4352 ssh2_pkt_init(ssh, SSH2_MSG_SERVICE_REQUEST);
4353 ssh2_pkt_addstring(ssh, "ssh-userauth");
4354 ssh2_pkt_send(ssh);
4355 crWaitUntilV(ispkt);
4356 if (ssh->pktin.type != SSH2_MSG_SERVICE_ACCEPT) {
4357 bombout(("Server refused user authentication protocol"));
4358 crReturnV;
4359 }
4360
4361 /*
4362 * We repeat this whole loop, including the username prompt,
4363 * until we manage a successful authentication. If the user
4364 * types the wrong _password_, they can be sent back to the
4365 * beginning to try another username, if this is configured on.
4366 * (If they specify a username in the config, they are never
4367 * asked, even if they do give a wrong password.)
4368 *
4369 * I think this best serves the needs of
4370 *
4371 * - the people who have no configuration, no keys, and just
4372 * want to try repeated (username,password) pairs until they
4373 * type both correctly
4374 *
4375 * - people who have keys and configuration but occasionally
4376 * need to fall back to passwords
4377 *
4378 * - people with a key held in Pageant, who might not have
4379 * logged in to a particular machine before; so they want to
4380 * type a username, and then _either_ their key will be
4381 * accepted, _or_ they will type a password. If they mistype
4382 * the username they will want to be able to get back and
4383 * retype it!
4384 */
4385 s->username[0] = '\0';
4386 s->got_username = FALSE;
4387 do {
4388 /*
4389 * Get a username.
4390 */
4391 if (s->got_username && !ssh->cfg.change_username) {
4392 /*
4393 * We got a username last time round this loop, and
4394 * with change_username turned off we don't try to get
4395 * it again.
4396 */
4397 } else if ((flags & FLAG_INTERACTIVE) && !*ssh->cfg.username) {
4398 if (ssh_get_line && !ssh_getline_pw_only) {
4399 if (!ssh_get_line("login as: ",
4400 s->username, sizeof(s->username), FALSE)) {
4401 /*
4402 * get_line failed to get a username.
4403 * Terminate.
4404 */
4405 logevent("No username provided. Abandoning session.");
4406 ssh_closing((Plug)ssh, NULL, 0, 0);
4407 crReturnV;
4408 }
4409 } else {
4410 int ret; /* need not be saved across crReturn */
4411 c_write_str(ssh, "login as: ");
4412 ssh->send_ok = 1;
4413 setup_userpass_input(ssh, s->username, sizeof(s->username), 1);
4414 do {
4415 crWaitUntilV(!ispkt);
4416 ret = process_userpass_input(ssh, in, inlen);
4417 } while (ret == 0);
4418 if (ret < 0)
4419 cleanup_exit(0);
4420 c_write_str(ssh, "\r\n");
4421 }
4422 s->username[strcspn(s->username, "\n\r")] = '\0';
4423 } else {
4424 char *stuff;
4425 strncpy(s->username, ssh->cfg.username, sizeof(s->username));
4426 s->username[sizeof(s->username)-1] = '\0';
4427 if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
4428 stuff = dupprintf("Using username \"%s\".\r\n", s->username);
4429 c_write_str(ssh, stuff);
4430 sfree(stuff);
4431 }
4432 }
4433 s->got_username = TRUE;
4434
4435 /*
4436 * Send an authentication request using method "none": (a)
4437 * just in case it succeeds, and (b) so that we know what
4438 * authentication methods we can usefully try next.
4439 */
4440 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4441
4442 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4443 ssh2_pkt_addstring(ssh, s->username);
4444 ssh2_pkt_addstring(ssh, "ssh-connection");/* service requested */
4445 ssh2_pkt_addstring(ssh, "none"); /* method */
4446 ssh2_pkt_send(ssh);
4447 s->type = AUTH_TYPE_NONE;
4448 s->gotit = FALSE;
4449 s->we_are_in = FALSE;
4450
4451 s->tried_pubkey_config = FALSE;
4452 s->tried_agent = FALSE;
4453 s->tried_keyb_inter = FALSE;
4454 s->kbd_inter_running = FALSE;
4455 /* Load the pub half of ssh->cfg.keyfile so we notice if it's in Pageant */
4456 if (!filename_is_null(ssh->cfg.keyfile)) {
4457 int keytype;
4458 logeventf(ssh, "Reading private key file \"%.150s\"",
4459 filename_to_str(&ssh->cfg.keyfile));
4460 keytype = key_type(&ssh->cfg.keyfile);
4461 if (keytype == SSH_KEYTYPE_SSH2) {
4462 s->publickey_blob =
4463 ssh2_userkey_loadpub(&ssh->cfg.keyfile, NULL,
4464 &s->publickey_bloblen);
4465 } else {
4466 char *msgbuf;
4467 logeventf(ssh, "Unable to use this key file (%s)",
4468 key_type_to_str(keytype));
4469 msgbuf = dupprintf("Unable to use key file \"%.150s\""
4470 " (%s)\r\n",
4471 filename_to_str(&ssh->cfg.keyfile),
4472 key_type_to_str(keytype));
4473 c_write_str(ssh, msgbuf);
4474 sfree(msgbuf);
4475 s->publickey_blob = NULL;
4476 }
4477 } else
4478 s->publickey_blob = NULL;
4479
4480 while (1) {
4481 /*
4482 * Wait for the result of the last authentication request.
4483 */
4484 if (!s->gotit)
4485 crWaitUntilV(ispkt);
4486 while (ssh->pktin.type == SSH2_MSG_USERAUTH_BANNER) {
4487 char *banner;
4488 int size;
4489 /*
4490 * Don't show the banner if we're operating in
4491 * non-verbose non-interactive mode. (It's probably
4492 * a script, which means nobody will read the
4493 * banner _anyway_, and moreover the printing of
4494 * the banner will screw up processing on the
4495 * output of (say) plink.)
4496 */
4497 if (flags & (FLAG_VERBOSE | FLAG_INTERACTIVE)) {
4498 ssh2_pkt_getstring(ssh, &banner, &size);
4499 if (banner)
4500 c_write_untrusted(ssh, banner, size);
4501 }
4502 crWaitUntilV(ispkt);
4503 }
4504 if (ssh->pktin.type == SSH2_MSG_USERAUTH_SUCCESS) {
4505 logevent("Access granted");
4506 s->we_are_in = TRUE;
4507 break;
4508 }
4509
4510 if (s->kbd_inter_running &&
4511 ssh->pktin.type == SSH2_MSG_USERAUTH_INFO_REQUEST) {
4512 /*
4513 * This is either a further set-of-prompts packet
4514 * in keyboard-interactive authentication, or it's
4515 * the same one and we came back here with `gotit'
4516 * set. In the former case, we must reset the
4517 * curr_prompt variable.
4518 */
4519 if (!s->gotit)
4520 s->curr_prompt = 0;
4521 } else if (ssh->pktin.type != SSH2_MSG_USERAUTH_FAILURE) {
4522 bombout(("Strange packet received during authentication: type %d",
4523 ssh->pktin.type));
4524 crReturnV;
4525 }
4526
4527 s->gotit = FALSE;
4528
4529 /*
4530 * OK, we're now sitting on a USERAUTH_FAILURE message, so
4531 * we can look at the string in it and know what we can
4532 * helpfully try next.
4533 */
4534 if (ssh->pktin.type == SSH2_MSG_USERAUTH_FAILURE) {
4535 char *methods;
4536 int methlen;
4537 ssh2_pkt_getstring(ssh, &methods, &methlen);
4538 s->kbd_inter_running = FALSE;
4539 if (!ssh2_pkt_getbool(ssh)) {
4540 /*
4541 * We have received an unequivocal Access
4542 * Denied. This can translate to a variety of
4543 * messages:
4544 *
4545 * - if we'd just tried "none" authentication,
4546 * it's not worth printing anything at all
4547 *
4548 * - if we'd just tried a public key _offer_,
4549 * the message should be "Server refused our
4550 * key" (or no message at all if the key
4551 * came from Pageant)
4552 *
4553 * - if we'd just tried anything else, the
4554 * message really should be "Access denied".
4555 *
4556 * Additionally, if we'd just tried password
4557 * authentication, we should break out of this
4558 * whole loop so as to go back to the username
4559 * prompt.
4560 */
4561 if (s->type == AUTH_TYPE_NONE) {
4562 /* do nothing */
4563 } else if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD ||
4564 s->type == AUTH_TYPE_PUBLICKEY_OFFER_QUIET) {
4565 if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD)
4566 c_write_str(ssh, "Server refused our key\r\n");
4567 logevent("Server refused public key");
4568 } else if (s->type==AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET) {
4569 /* server declined keyboard-interactive; ignore */
4570 } else {
4571 c_write_str(ssh, "Access denied\r\n");
4572 logevent("Access denied");
4573 if (s->type == AUTH_TYPE_PASSWORD) {
4574 s->we_are_in = FALSE;
4575 break;
4576 }
4577 }
4578 } else {
4579 c_write_str(ssh, "Further authentication required\r\n");
4580 logevent("Further authentication required");
4581 }
4582
4583 s->can_pubkey =
4584 in_commasep_string("publickey", methods, methlen);
4585 s->can_passwd =
4586 in_commasep_string("password", methods, methlen);
4587 s->can_keyb_inter = ssh->cfg.try_ki_auth &&
4588 in_commasep_string("keyboard-interactive", methods, methlen);
4589 }
4590
4591 s->method = 0;
4592 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4593
4594 /*
4595 * Most password/passphrase prompts will be
4596 * non-echoing, so we set this to 0 by default.
4597 * Exception is that some keyboard-interactive prompts
4598 * can be echoing, in which case we'll set this to 1.
4599 */
4600 s->echo = 0;
4601
4602 if (!s->method && s->can_pubkey &&
4603 agent_exists() && !s->tried_agent) {
4604 /*
4605 * Attempt public-key authentication using Pageant.
4606 */
4607 void *r;
4608 s->authed = FALSE;
4609
4610 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4611 ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
4612
4613 s->tried_agent = TRUE;
4614
4615 logevent("Pageant is running. Requesting keys.");
4616
4617 /* Request the keys held by the agent. */
4618 PUT_32BIT(s->request, 1);
4619 s->request[4] = SSH2_AGENTC_REQUEST_IDENTITIES;
4620 agent_query(s->request, 5, &r, &s->responselen);
4621 s->response = (unsigned char *) r;
4622 if (s->response && s->responselen >= 5 &&
4623 s->response[4] == SSH2_AGENT_IDENTITIES_ANSWER) {
4624 s->p = s->response + 5;
4625 s->nkeys = GET_32BIT(s->p);
4626 s->p += 4;
4627 {
4628 char buf[64];
4629 sprintf(buf, "Pageant has %d SSH2 keys", s->nkeys);
4630 logevent(buf);
4631 }
4632 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
4633 void *vret;
4634
4635 {
4636 char buf[64];
4637 sprintf(buf, "Trying Pageant key #%d", s->keyi);
4638 logevent(buf);
4639 }
4640 s->pklen = GET_32BIT(s->p);
4641 s->p += 4;
4642 if (s->publickey_blob &&
4643 s->pklen == s->publickey_bloblen &&
4644 !memcmp(s->p, s->publickey_blob,
4645 s->publickey_bloblen)) {
4646 logevent("This key matches configured key file");
4647 s->tried_pubkey_config = 1;
4648 }
4649 s->pkblob = (char *)s->p;
4650 s->p += s->pklen;
4651 s->alglen = GET_32BIT(s->pkblob);
4652 s->alg = s->pkblob + 4;
4653 s->commentlen = GET_32BIT(s->p);
4654 s->p += 4;
4655 s->commentp = (char *)s->p;
4656 s->p += s->commentlen;
4657 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4658 ssh2_pkt_addstring(ssh, s->username);
4659 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4660 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4661 ssh2_pkt_addbool(ssh, FALSE); /* no signature included */
4662 ssh2_pkt_addstring_start(ssh);
4663 ssh2_pkt_addstring_data(ssh, s->alg, s->alglen);
4664 ssh2_pkt_addstring_start(ssh);
4665 ssh2_pkt_addstring_data(ssh, s->pkblob, s->pklen);
4666 ssh2_pkt_send(ssh);
4667
4668 crWaitUntilV(ispkt);
4669 if (ssh->pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
4670 logevent("Key refused");
4671 continue;
4672 }
4673
4674 if (flags & FLAG_VERBOSE) {
4675 c_write_str(ssh, "Authenticating with "
4676 "public key \"");
4677 c_write(ssh, s->commentp, s->commentlen);
4678 c_write_str(ssh, "\" from agent\r\n");
4679 }
4680
4681 /*
4682 * Server is willing to accept the key.
4683 * Construct a SIGN_REQUEST.
4684 */
4685 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4686 ssh2_pkt_addstring(ssh, s->username);
4687 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4688 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4689 ssh2_pkt_addbool(ssh, TRUE);
4690 ssh2_pkt_addstring_start(ssh);
4691 ssh2_pkt_addstring_data(ssh, s->alg, s->alglen);
4692 ssh2_pkt_addstring_start(ssh);
4693 ssh2_pkt_addstring_data(ssh, s->pkblob, s->pklen);
4694
4695 s->siglen = ssh->pktout.length - 5 + 4 + 20;
4696 if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
4697 s->siglen -= 4;
4698 s->len = 1; /* message type */
4699 s->len += 4 + s->pklen; /* key blob */
4700 s->len += 4 + s->siglen; /* data to sign */
4701 s->len += 4; /* flags */
4702 s->agentreq = snewn(4 + s->len, char);
4703 PUT_32BIT(s->agentreq, s->len);
4704 s->q = s->agentreq + 4;
4705 *s->q++ = SSH2_AGENTC_SIGN_REQUEST;
4706 PUT_32BIT(s->q, s->pklen);
4707 s->q += 4;
4708 memcpy(s->q, s->pkblob, s->pklen);
4709 s->q += s->pklen;
4710 PUT_32BIT(s->q, s->siglen);
4711 s->q += 4;
4712 /* Now the data to be signed... */
4713 if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
4714 PUT_32BIT(s->q, 20);
4715 s->q += 4;
4716 }
4717 memcpy(s->q, ssh->v2_session_id, 20);
4718 s->q += 20;
4719 memcpy(s->q, ssh->pktout.data + 5,
4720 ssh->pktout.length - 5);
4721 s->q += ssh->pktout.length - 5;
4722 /* And finally the (zero) flags word. */
4723 PUT_32BIT(s->q, 0);
4724 agent_query(s->agentreq, s->len + 4, &vret, &s->retlen);
4725 s->ret = vret;
4726 sfree(s->agentreq);
4727 if (s->ret) {
4728 if (s->ret[4] == SSH2_AGENT_SIGN_RESPONSE) {
4729 logevent("Sending Pageant's response");
4730 ssh2_add_sigblob(ssh, s->pkblob, s->pklen,
4731 s->ret + 9,
4732 GET_32BIT(s->ret + 5));
4733 ssh2_pkt_send(ssh);
4734 s->authed = TRUE;
4735 break;
4736 } else {
4737 logevent
4738 ("Pageant failed to answer challenge");
4739 sfree(s->ret);
4740 }
4741 }
4742 }
4743 if (s->authed)
4744 continue;
4745 }
4746 }
4747
4748 if (!s->method && s->can_pubkey && s->publickey_blob
4749 && !s->tried_pubkey_config) {
4750 unsigned char *pub_blob;
4751 char *algorithm, *comment;
4752 int pub_blob_len;
4753
4754 s->tried_pubkey_config = TRUE;
4755
4756 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4757 ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
4758
4759 /*
4760 * Try the public key supplied in the configuration.
4761 *
4762 * First, offer the public blob to see if the server is
4763 * willing to accept it.
4764 */
4765 pub_blob =
4766 (unsigned char *)ssh2_userkey_loadpub(&ssh->cfg.keyfile,
4767 &algorithm,
4768 &pub_blob_len);
4769 if (pub_blob) {
4770 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4771 ssh2_pkt_addstring(ssh, s->username);
4772 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4773 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4774 ssh2_pkt_addbool(ssh, FALSE); /* no signature included */
4775 ssh2_pkt_addstring(ssh, algorithm);
4776 ssh2_pkt_addstring_start(ssh);
4777 ssh2_pkt_addstring_data(ssh, (char *)pub_blob,
4778 pub_blob_len);
4779 ssh2_pkt_send(ssh);
4780 logevent("Offered public key"); /* FIXME */
4781
4782 crWaitUntilV(ispkt);
4783 if (ssh->pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
4784 s->gotit = TRUE;
4785 s->type = AUTH_TYPE_PUBLICKEY_OFFER_LOUD;
4786 continue; /* key refused; give up on it */
4787 }
4788
4789 logevent("Offer of public key accepted");
4790 /*
4791 * Actually attempt a serious authentication using
4792 * the key.
4793 */
4794 if (ssh2_userkey_encrypted(&ssh->cfg.keyfile, &comment)) {
4795 sprintf(s->pwprompt,
4796 "Passphrase for key \"%.100s\": ",
4797 comment);
4798 s->need_pw = TRUE;
4799 } else {
4800 s->need_pw = FALSE;
4801 }
4802 c_write_str(ssh, "Authenticating with public key \"");
4803 c_write_str(ssh, comment);
4804 c_write_str(ssh, "\"\r\n");
4805 s->method = AUTH_PUBLICKEY_FILE;
4806 }
4807 }
4808
4809 if (!s->method && s->can_keyb_inter && !s->tried_keyb_inter) {
4810 s->method = AUTH_KEYBOARD_INTERACTIVE;
4811 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
4812 s->tried_keyb_inter = TRUE;
4813
4814 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4815 ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;
4816
4817 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4818 ssh2_pkt_addstring(ssh, s->username);
4819 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4820 ssh2_pkt_addstring(ssh, "keyboard-interactive"); /* method */
4821 ssh2_pkt_addstring(ssh, ""); /* lang */
4822 ssh2_pkt_addstring(ssh, "");
4823 ssh2_pkt_send(ssh);
4824
4825 crWaitUntilV(ispkt);
4826 if (ssh->pktin.type != SSH2_MSG_USERAUTH_INFO_REQUEST) {
4827 if (ssh->pktin.type == SSH2_MSG_USERAUTH_FAILURE)
4828 s->gotit = TRUE;
4829 logevent("Keyboard-interactive authentication refused");
4830 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET;
4831 continue;
4832 }
4833
4834 s->kbd_inter_running = TRUE;
4835 s->curr_prompt = 0;
4836 }
4837
4838 if (s->kbd_inter_running) {
4839 s->method = AUTH_KEYBOARD_INTERACTIVE;
4840 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
4841 s->tried_keyb_inter = TRUE;
4842
4843 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4844 ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;
4845
4846 if (s->curr_prompt == 0) {
4847 /*
4848 * We've got a fresh USERAUTH_INFO_REQUEST.
4849 * Display header data, and start going through
4850 * the prompts.
4851 */
4852 char *name, *inst, *lang;
4853 int name_len, inst_len, lang_len;
4854
4855 ssh2_pkt_getstring(ssh, &name, &name_len);
4856 ssh2_pkt_getstring(ssh, &inst, &inst_len);
4857 ssh2_pkt_getstring(ssh, &lang, &lang_len);
4858 if (name_len > 0) {
4859 c_write_untrusted(ssh, name, name_len);
4860 c_write_str(ssh, "\r\n");
4861 }
4862 if (inst_len > 0) {
4863 c_write_untrusted(ssh, inst, inst_len);
4864 c_write_str(ssh, "\r\n");
4865 }
4866 s->num_prompts = ssh2_pkt_getuint32(ssh);
4867 }
4868
4869 /*
4870 * If there are prompts remaining in the packet,
4871 * display one and get a response.
4872 */
4873 if (s->curr_prompt < s->num_prompts) {
4874 char *prompt;
4875 int prompt_len;
4876
4877 ssh2_pkt_getstring(ssh, &prompt, &prompt_len);
4878 if (prompt_len > 0) {
4879 strncpy(s->pwprompt, prompt, sizeof(s->pwprompt));
4880 s->pwprompt[prompt_len < sizeof(s->pwprompt) ?
4881 prompt_len : sizeof(s->pwprompt)-1] = '\0';
4882 } else {
4883 strcpy(s->pwprompt,
4884 "<server failed to send prompt>: ");
4885 }
4886 s->echo = ssh2_pkt_getbool(ssh);
4887 s->need_pw = TRUE;
4888 } else
4889 s->need_pw = FALSE;
4890 }
4891
4892 if (!s->method && s->can_passwd) {
4893 s->method = AUTH_PASSWORD;
4894 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4895 ssh->pkt_ctx |= SSH2_PKTCTX_PASSWORD;
4896 sprintf(s->pwprompt, "%.90s@%.90s's password: ", s->username,
4897 ssh->savedhost);
4898 s->need_pw = TRUE;
4899 }
4900
4901 if (s->need_pw) {
4902 if (ssh_get_line) {
4903 if (!ssh_get_line(s->pwprompt, s->password,
4904 sizeof(s->password), TRUE)) {
4905 /*
4906 * get_line failed to get a password (for
4907 * example because one was supplied on the
4908 * command line which has already failed to
4909 * work). Terminate.
4910 */
4911 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
4912 ssh2_pkt_adduint32(ssh,SSH2_DISCONNECT_BY_APPLICATION);
4913 ssh2_pkt_addstring(ssh, "No more passwords available"
4914 " to try");
4915 ssh2_pkt_addstring(ssh, "en"); /* language tag */
4916 ssh2_pkt_send(ssh);
4917 logevent("Unable to authenticate");
4918 connection_fatal(ssh->frontend,
4919 "Unable to authenticate");
4920 ssh_closing((Plug)ssh, NULL, 0, 0);
4921 crReturnV;
4922 }
4923 } else {
4924 int ret; /* need not be saved across crReturn */
4925 c_write_untrusted(ssh, s->pwprompt, strlen(s->pwprompt));
4926 ssh->send_ok = 1;
4927
4928 setup_userpass_input(ssh, s->password,
4929 sizeof(s->password), s->echo);
4930 do {
4931 crWaitUntilV(!ispkt);
4932 ret = process_userpass_input(ssh, in, inlen);
4933 } while (ret == 0);
4934 if (ret < 0)
4935 cleanup_exit(0);
4936 c_write_str(ssh, "\r\n");
4937 }
4938 }
4939
4940 if (s->method == AUTH_PUBLICKEY_FILE) {
4941 /*
4942 * We have our passphrase. Now try the actual authentication.
4943 */
4944 struct ssh2_userkey *key;
4945
4946 key = ssh2_load_userkey(&ssh->cfg.keyfile, s->password);
4947 if (key == SSH2_WRONG_PASSPHRASE || key == NULL) {
4948 if (key == SSH2_WRONG_PASSPHRASE) {
4949 c_write_str(ssh, "Wrong passphrase\r\n");
4950 s->tried_pubkey_config = FALSE;
4951 } else {
4952 c_write_str(ssh, "Unable to load private key\r\n");
4953 s->tried_pubkey_config = TRUE;
4954 }
4955 /* Send a spurious AUTH_NONE to return to the top. */
4956 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4957 ssh2_pkt_addstring(ssh, s->username);
4958 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4959 ssh2_pkt_addstring(ssh, "none"); /* method */
4960 ssh2_pkt_send(ssh);
4961 s->type = AUTH_TYPE_NONE;
4962 } else {
4963 unsigned char *pkblob, *sigblob, *sigdata;
4964 int pkblob_len, sigblob_len, sigdata_len;
4965 int p;
4966
4967 /*
4968 * We have loaded the private key and the server
4969 * has announced that it's willing to accept it.
4970 * Hallelujah. Generate a signature and send it.
4971 */
4972 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4973 ssh2_pkt_addstring(ssh, s->username);
4974 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4975 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4976 ssh2_pkt_addbool(ssh, TRUE);
4977 ssh2_pkt_addstring(ssh, key->alg->name);
4978 pkblob = key->alg->public_blob(key->data, &pkblob_len);
4979 ssh2_pkt_addstring_start(ssh);
4980 ssh2_pkt_addstring_data(ssh, (char *)pkblob, pkblob_len);
4981
4982 /*
4983 * The data to be signed is:
4984 *
4985 * string session-id
4986 *
4987 * followed by everything so far placed in the
4988 * outgoing packet.
4989 */
4990 sigdata_len = ssh->pktout.length - 5 + 4 + 20;
4991 if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
4992 sigdata_len -= 4;
4993 sigdata = snewn(sigdata_len, unsigned char);
4994 p = 0;
4995 if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
4996 PUT_32BIT(sigdata+p, 20);
4997 p += 4;
4998 }
4999 memcpy(sigdata+p, ssh->v2_session_id, 20); p += 20;
5000 memcpy(sigdata+p, ssh->pktout.data + 5,
5001 ssh->pktout.length - 5);
5002 p += ssh->pktout.length - 5;
5003 assert(p == sigdata_len);
5004 sigblob = key->alg->sign(key->data, (char *)sigdata,
5005 sigdata_len, &sigblob_len);
5006 ssh2_add_sigblob(ssh, pkblob, pkblob_len,
5007 sigblob, sigblob_len);
5008 sfree(pkblob);
5009 sfree(sigblob);
5010 sfree(sigdata);
5011
5012 ssh2_pkt_send(ssh);
5013 s->type = AUTH_TYPE_PUBLICKEY;
5014 }
5015 } else if (s->method == AUTH_PASSWORD) {
5016 /*
5017 * We send the password packet lumped tightly together with
5018 * an SSH_MSG_IGNORE packet. The IGNORE packet contains a
5019 * string long enough to make the total length of the two
5020 * packets constant. This should ensure that a passive
5021 * listener doing traffic analyis can't work out the length
5022 * of the password.
5023 *
5024 * For this to work, we need an assumption about the
5025 * maximum length of the password packet. I think 256 is
5026 * pretty conservative. Anyone using a password longer than
5027 * that probably doesn't have much to worry about from
5028 * people who find out how long their password is!
5029 */
5030 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
5031 ssh2_pkt_addstring(ssh, s->username);
5032 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
5033 ssh2_pkt_addstring(ssh, "password");
5034 ssh2_pkt_addbool(ssh, FALSE);
5035 ssh2_pkt_addstring(ssh, s->password);
5036 memset(s->password, 0, sizeof(s->password));
5037 ssh2_pkt_defer(ssh);
5038 /*
5039 * We'll include a string that's an exact multiple of the
5040 * cipher block size. If the cipher is NULL for some
5041 * reason, we don't do this trick at all because we gain
5042 * nothing by it.
5043 */
5044 if (ssh->cscipher) {
5045 int stringlen, i;
5046
5047 stringlen = (256 - ssh->deferred_len);
5048 stringlen += ssh->cscipher->blksize - 1;
5049 stringlen -= (stringlen % ssh->cscipher->blksize);
5050 if (ssh->cscomp) {
5051 /*
5052 * Temporarily disable actual compression,
5053 * so we can guarantee to get this string
5054 * exactly the length we want it. The
5055 * compression-disabling routine should
5056 * return an integer indicating how many
5057 * bytes we should adjust our string length
5058 * by.
5059 */
5060 stringlen -=
5061 ssh->cscomp->disable_compression(ssh->cs_comp_ctx);
5062 }
5063 ssh2_pkt_init(ssh, SSH2_MSG_IGNORE);
5064 ssh2_pkt_addstring_start(ssh);
5065 for (i = 0; i < stringlen; i++) {
5066 char c = (char) random_byte();
5067 ssh2_pkt_addstring_data(ssh, &c, 1);
5068 }
5069 ssh2_pkt_defer(ssh);
5070 }
5071 ssh_pkt_defersend(ssh);
5072 logevent("Sent password");
5073 s->type = AUTH_TYPE_PASSWORD;
5074 } else if (s->method == AUTH_KEYBOARD_INTERACTIVE) {
5075 if (s->curr_prompt == 0) {
5076 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_INFO_RESPONSE);
5077 ssh2_pkt_adduint32(ssh, s->num_prompts);
5078 }
5079 if (s->need_pw) { /* only add pw if we just got one! */
5080 ssh2_pkt_addstring(ssh, s->password);
5081 memset(s->password, 0, sizeof(s->password));
5082 s->curr_prompt++;
5083 }
5084 if (s->curr_prompt >= s->num_prompts) {
5085 ssh2_pkt_send(ssh);
5086 } else {
5087 /*
5088 * If there are prompts remaining, we set
5089 * `gotit' so that we won't attempt to get
5090 * another packet. Then we go back round the
5091 * loop and will end up retrieving another
5092 * prompt out of the existing packet. Funky or
5093 * what?
5094 */
5095 s->gotit = TRUE;
5096 }
5097 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
5098 } else {
5099 c_write_str(ssh, "No supported authentication methods"
5100 " left to try!\r\n");
5101 logevent("No supported authentications offered."
5102 " Disconnecting");
5103 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5104 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5105 ssh2_pkt_addstring(ssh, "No supported authentication"
5106 " methods available");
5107 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5108 ssh2_pkt_send(ssh);
5109 ssh_closing((Plug)ssh, NULL, 0, 0);
5110 crReturnV;
5111 }
5112 }
5113 } while (!s->we_are_in);
5114
5115 /*
5116 * Now we're authenticated for the connection protocol. The
5117 * connection protocol will automatically have started at this
5118 * point; there's no need to send SERVICE_REQUEST.
5119 */
5120
5121 /*
5122 * So now create a channel with a session in it.
5123 */
5124 ssh->channels = newtree234(ssh_channelcmp);
5125 ssh->mainchan = snew(struct ssh_channel);
5126 ssh->mainchan->ssh = ssh;
5127 ssh->mainchan->localid = alloc_channel_id(ssh);
5128 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN);
5129 ssh2_pkt_addstring(ssh, "session");
5130 ssh2_pkt_adduint32(ssh, ssh->mainchan->localid);
5131 ssh->mainchan->v.v2.locwindow = OUR_V2_WINSIZE;
5132 ssh2_pkt_adduint32(ssh, ssh->mainchan->v.v2.locwindow);/* our window size */
5133 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
5134 ssh2_pkt_send(ssh);
5135 crWaitUntilV(ispkt);
5136 if (ssh->pktin.type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
5137 bombout(("Server refused to open a session"));
5138 crReturnV;
5139 /* FIXME: error data comes back in FAILURE packet */
5140 }
5141 if (ssh2_pkt_getuint32(ssh) != ssh->mainchan->localid) {
5142 bombout(("Server's channel confirmation cited wrong channel"));
5143 crReturnV;
5144 }
5145 ssh->mainchan->remoteid = ssh2_pkt_getuint32(ssh);
5146 ssh->mainchan->type = CHAN_MAINSESSION;
5147 ssh->mainchan->closes = 0;
5148 ssh->mainchan->v.v2.remwindow = ssh2_pkt_getuint32(ssh);
5149 ssh->mainchan->v.v2.remmaxpkt = ssh2_pkt_getuint32(ssh);
5150 bufchain_init(&ssh->mainchan->v.v2.outbuffer);
5151 add234(ssh->channels, ssh->mainchan);
5152 logevent("Opened channel for session");
5153
5154 /*
5155 * Potentially enable X11 forwarding.
5156 */
5157 if (ssh->cfg.x11_forward) {
5158 char proto[20], data[64];
5159 logevent("Requesting X11 forwarding");
5160 ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
5161 data, sizeof(data), ssh->cfg.x11_auth);
5162 x11_get_real_auth(ssh->x11auth, ssh->cfg.x11_display);
5163 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5164 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
5165 ssh2_pkt_addstring(ssh, "x11-req");
5166 ssh2_pkt_addbool(ssh, 1); /* want reply */
5167 ssh2_pkt_addbool(ssh, 0); /* many connections */
5168 ssh2_pkt_addstring(ssh, proto);
5169 ssh2_pkt_addstring(ssh, data);
5170 ssh2_pkt_adduint32(ssh, x11_get_screen_number(ssh->cfg.x11_display));
5171 ssh2_pkt_send(ssh);
5172
5173 do {
5174 crWaitUntilV(ispkt);
5175 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5176 unsigned i = ssh2_pkt_getuint32(ssh);
5177 struct ssh_channel *c;
5178 c = find234(ssh->channels, &i, ssh_channelfind);
5179 if (!c)
5180 continue; /* nonexistent channel */
5181 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5182 }
5183 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5184
5185 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5186 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5187 bombout(("Unexpected response to X11 forwarding request:"
5188 " packet type %d", ssh->pktin.type));
5189 crReturnV;
5190 }
5191 logevent("X11 forwarding refused");
5192 } else {
5193 logevent("X11 forwarding enabled");
5194 ssh->X11_fwd_enabled = TRUE;
5195 }
5196 }
5197
5198 /*
5199 * Enable port forwardings.
5200 */
5201 {
5202 char type;
5203 int n;
5204 int sport,dport,sserv,dserv;
5205 char sports[256], dports[256], saddr[256], host[256];
5206
5207 ssh->rportfwds = newtree234(ssh_rportcmp_ssh2);
5208 /* Add port forwardings. */
5209 ssh->portfwd_strptr = ssh->cfg.portfwd;
5210 while (*ssh->portfwd_strptr) {
5211 type = *ssh->portfwd_strptr++;
5212 saddr[0] = '\0';
5213 n = 0;
5214 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != '\t') {
5215 if (*ssh->portfwd_strptr == ':') {
5216 /*
5217 * We've seen a colon in the middle of the
5218 * source port number. This means that
5219 * everything we've seen until now is the
5220 * source _address_, so we'll move it into
5221 * saddr and start sports from the beginning
5222 * again.
5223 */
5224 ssh->portfwd_strptr++;
5225 sports[n] = '\0';
5226 strcpy(saddr, sports);
5227 n = 0;
5228 }
5229 if (n < 255) sports[n++] = *ssh->portfwd_strptr++;
5230 }
5231 sports[n] = 0;
5232 if (*ssh->portfwd_strptr == '\t')
5233 ssh->portfwd_strptr++;
5234 n = 0;
5235 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':') {
5236 if (n < 255) host[n++] = *ssh->portfwd_strptr++;
5237 }
5238 host[n] = 0;
5239 if (*ssh->portfwd_strptr == ':')
5240 ssh->portfwd_strptr++;
5241 n = 0;
5242 while (*ssh->portfwd_strptr) {
5243 if (n < 255) dports[n++] = *ssh->portfwd_strptr++;
5244 }
5245 dports[n] = 0;
5246 ssh->portfwd_strptr++;
5247 dport = atoi(dports);
5248 dserv = 0;
5249 if (dport == 0) {
5250 dserv = 1;
5251 dport = net_service_lookup(dports);
5252 if (!dport) {
5253 logeventf(ssh, "Service lookup failed for destination"
5254 " port \"%s\"", dports);
5255 }
5256 }
5257 sport = atoi(sports);
5258 sserv = 0;
5259 if (sport == 0) {
5260 sserv = 1;
5261 sport = net_service_lookup(sports);
5262 if (!sport) {
5263 logeventf(ssh, "Service lookup failed for source"
5264 " port \"%s\"", sports);
5265 }
5266 }
5267 if (sport && dport) {
5268 if (type == 'L') {
5269 pfd_addforward(host, dport, *saddr ? saddr : NULL,
5270 sport, ssh, &ssh->cfg);
5271 logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
5272 " forwarding to %s:%.*s%.*s%d%.*s",
5273 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
5274 (int)(*saddr?1:0), ":",
5275 (int)(sserv ? strlen(sports) : 0), sports,
5276 sserv, "(", sport, sserv, ")",
5277 host,
5278 (int)(dserv ? strlen(dports) : 0), dports,
5279 dserv, "(", dport, dserv, ")");
5280 } else {
5281 struct ssh_rportfwd *pf;
5282 pf = snew(struct ssh_rportfwd);
5283 strcpy(pf->dhost, host);
5284 pf->dport = dport;
5285 pf->sport = sport;
5286 if (add234(ssh->rportfwds, pf) != pf) {
5287 logeventf(ssh, "Duplicate remote port forwarding"
5288 " to %s:%d", host, dport);
5289 sfree(pf);
5290 } else {
5291 logeventf(ssh, "Requesting remote port "
5292 "%.*s%.*s%.*s%.*s%d%.*s"
5293 " forward to %s:%.*s%.*s%d%.*s",
5294 (int)(*saddr?strlen(saddr):0),
5295 *saddr?saddr:NULL,
5296 (int)(*saddr?1:0), ":",
5297 (int)(sserv ? strlen(sports) : 0), sports,
5298 sserv, "(", sport, sserv, ")",
5299 host,
5300 (int)(dserv ? strlen(dports) : 0), dports,
5301 dserv, "(", dport, dserv, ")");
5302 ssh2_pkt_init(ssh, SSH2_MSG_GLOBAL_REQUEST);
5303 ssh2_pkt_addstring(ssh, "tcpip-forward");
5304 ssh2_pkt_addbool(ssh, 1);/* want reply */
5305 if (*saddr)
5306 ssh2_pkt_addstring(ssh, saddr);
5307 if (ssh->cfg.rport_acceptall)
5308 ssh2_pkt_addstring(ssh, "0.0.0.0");
5309 else
5310 ssh2_pkt_addstring(ssh, "127.0.0.1");
5311 ssh2_pkt_adduint32(ssh, sport);
5312 ssh2_pkt_send(ssh);
5313
5314 do {
5315 crWaitUntilV(ispkt);
5316 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5317 unsigned i = ssh2_pkt_getuint32(ssh);
5318 struct ssh_channel *c;
5319 c = find234(ssh->channels, &i, ssh_channelfind);
5320 if (!c)
5321 continue;/* nonexistent channel */
5322 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5323 }
5324 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5325
5326 if (ssh->pktin.type != SSH2_MSG_REQUEST_SUCCESS) {
5327 if (ssh->pktin.type != SSH2_MSG_REQUEST_FAILURE) {
5328 bombout(("Unexpected response to port "
5329 "forwarding request: packet type %d",
5330 ssh->pktin.type));
5331 crReturnV;
5332 }
5333 logevent("Server refused this port forwarding");
5334 } else {
5335 logevent("Remote port forwarding enabled");
5336 }
5337 }
5338 }
5339 }
5340 }
5341 }
5342
5343 /*
5344 * Potentially enable agent forwarding.
5345 */
5346 if (ssh->cfg.agentfwd && agent_exists()) {
5347 logevent("Requesting OpenSSH-style agent forwarding");
5348 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5349 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
5350 ssh2_pkt_addstring(ssh, "auth-agent-req@openssh.com");
5351 ssh2_pkt_addbool(ssh, 1); /* want reply */
5352 ssh2_pkt_send(ssh);
5353
5354 do {
5355 crWaitUntilV(ispkt);
5356 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5357 unsigned i = ssh2_pkt_getuint32(ssh);
5358 struct ssh_channel *c;
5359 c = find234(ssh->channels, &i, ssh_channelfind);
5360 if (!c)
5361 continue; /* nonexistent channel */
5362 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5363 }
5364 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5365
5366 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5367 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5368 bombout(("Unexpected response to agent forwarding request:"
5369 " packet type %d", ssh->pktin.type));
5370 crReturnV;
5371 }
5372 logevent("Agent forwarding refused");
5373 } else {
5374 logevent("Agent forwarding enabled");
5375 ssh->agentfwd_enabled = TRUE;
5376 }
5377 }
5378
5379 /*
5380 * Now allocate a pty for the session.
5381 */
5382 if (!ssh->cfg.nopty) {
5383 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5384 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid); /* recipient channel */
5385 ssh2_pkt_addstring(ssh, "pty-req");
5386 ssh2_pkt_addbool(ssh, 1); /* want reply */
5387 ssh2_pkt_addstring(ssh, ssh->cfg.termtype);
5388 ssh2_pkt_adduint32(ssh, ssh->term_width);
5389 ssh2_pkt_adduint32(ssh, ssh->term_height);
5390 ssh2_pkt_adduint32(ssh, 0); /* pixel width */
5391 ssh2_pkt_adduint32(ssh, 0); /* pixel height */
5392 ssh2_pkt_addstring_start(ssh);
5393 ssh2_pkt_addstring_data(ssh, "\0", 1); /* TTY_OP_END, no special options */
5394 ssh2_pkt_send(ssh);
5395 ssh->state = SSH_STATE_INTERMED;
5396
5397 do {
5398 crWaitUntilV(ispkt);
5399 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5400 unsigned i = ssh2_pkt_getuint32(ssh);
5401 struct ssh_channel *c;
5402 c = find234(ssh->channels, &i, ssh_channelfind);
5403 if (!c)
5404 continue; /* nonexistent channel */
5405 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5406 }
5407 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5408
5409 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5410 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5411 bombout(("Unexpected response to pty request:"
5412 " packet type %d", ssh->pktin.type));
5413 crReturnV;
5414 }
5415 c_write_str(ssh, "Server refused to allocate pty\r\n");
5416 ssh->editing = ssh->echoing = 1;
5417 } else {
5418 logevent("Allocated pty");
5419 }
5420 } else {
5421 ssh->editing = ssh->echoing = 1;
5422 }
5423
5424 /*
5425 * Start a shell or a remote command. We may have to attempt
5426 * this twice if the config data has provided a second choice
5427 * of command.
5428 */
5429 while (1) {
5430 int subsys;
5431 char *cmd;
5432
5433 if (ssh->fallback_cmd) {
5434 subsys = ssh->cfg.ssh_subsys2;
5435 cmd = ssh->cfg.remote_cmd_ptr2;
5436 } else {
5437 subsys = ssh->cfg.ssh_subsys;
5438 cmd = ssh->cfg.remote_cmd_ptr;
5439 }
5440
5441 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5442 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid); /* recipient channel */
5443 if (subsys) {
5444 ssh2_pkt_addstring(ssh, "subsystem");
5445 ssh2_pkt_addbool(ssh, 1); /* want reply */
5446 ssh2_pkt_addstring(ssh, cmd);
5447 } else if (*cmd) {
5448 ssh2_pkt_addstring(ssh, "exec");
5449 ssh2_pkt_addbool(ssh, 1); /* want reply */
5450 ssh2_pkt_addstring(ssh, cmd);
5451 } else {
5452 ssh2_pkt_addstring(ssh, "shell");
5453 ssh2_pkt_addbool(ssh, 1); /* want reply */
5454 }
5455 ssh2_pkt_send(ssh);
5456 do {
5457 crWaitUntilV(ispkt);
5458 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5459 unsigned i = ssh2_pkt_getuint32(ssh);
5460 struct ssh_channel *c;
5461 c = find234(ssh->channels, &i, ssh_channelfind);
5462 if (!c)
5463 continue; /* nonexistent channel */
5464 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5465 }
5466 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5467 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5468 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5469 bombout(("Unexpected response to shell/command request:"
5470 " packet type %d", ssh->pktin.type));
5471 crReturnV;
5472 }
5473 /*
5474 * We failed to start the command. If this is the
5475 * fallback command, we really are finished; if it's
5476 * not, and if the fallback command exists, try falling
5477 * back to it before complaining.
5478 */
5479 if (!ssh->fallback_cmd && ssh->cfg.remote_cmd_ptr2 != NULL) {
5480 logevent("Primary command failed; attempting fallback");
5481 ssh->fallback_cmd = TRUE;
5482 continue;
5483 }
5484 bombout(("Server refused to start a shell/command"));
5485 crReturnV;
5486 } else {
5487 logevent("Started a shell/command");
5488 }
5489 break;
5490 }
5491
5492 ssh->state = SSH_STATE_SESSION;
5493 if (ssh->size_needed)
5494 ssh_size(ssh, ssh->term_width, ssh->term_height);
5495 if (ssh->eof_needed)
5496 ssh_special(ssh, TS_EOF);
5497
5498 /*
5499 * Transfer data!
5500 */
5501 if (ssh->ldisc)
5502 ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */
5503 ssh->send_ok = 1;
5504 while (1) {
5505 crReturnV;
5506 s->try_send = FALSE;
5507 if (ispkt) {
5508 if (ssh->pktin.type == SSH2_MSG_CHANNEL_DATA ||
5509 ssh->pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA) {
5510 char *data;
5511 int length;
5512 unsigned i = ssh2_pkt_getuint32(ssh);
5513 struct ssh_channel *c;
5514 c = find234(ssh->channels, &i, ssh_channelfind);
5515 if (!c)
5516 continue; /* nonexistent channel */
5517 if (ssh->pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
5518 ssh2_pkt_getuint32(ssh) != SSH2_EXTENDED_DATA_STDERR)
5519 continue; /* extended but not stderr */
5520 ssh2_pkt_getstring(ssh, &data, &length);
5521 if (data) {
5522 int bufsize;
5523 c->v.v2.locwindow -= length;
5524 switch (c->type) {
5525 case CHAN_MAINSESSION:
5526 bufsize =
5527 from_backend(ssh->frontend, ssh->pktin.type ==
5528 SSH2_MSG_CHANNEL_EXTENDED_DATA,
5529 data, length);
5530 break;
5531 case CHAN_X11:
5532 bufsize = x11_send(c->u.x11.s, data, length);
5533 break;
5534 case CHAN_SOCKDATA:
5535 bufsize = pfd_send(c->u.pfd.s, data, length);
5536 break;
5537 case CHAN_AGENT:
5538 while (length > 0) {
5539 if (c->u.a.lensofar < 4) {
5540 int l = min(4 - c->u.a.lensofar, length);
5541 memcpy(c->u.a.msglen + c->u.a.lensofar,
5542 data, l);
5543 data += l;
5544 length -= l;
5545 c->u.a.lensofar += l;
5546 }
5547 if (c->u.a.lensofar == 4) {
5548 c->u.a.totallen =
5549 4 + GET_32BIT(c->u.a.msglen);
5550 c->u.a.message = snewn(c->u.a.totallen,
5551 unsigned char);
5552 memcpy(c->u.a.message, c->u.a.msglen, 4);
5553 }
5554 if (c->u.a.lensofar >= 4 && length > 0) {
5555 int l =
5556 min(c->u.a.totallen - c->u.a.lensofar,
5557 length);
5558 memcpy(c->u.a.message + c->u.a.lensofar,
5559 data, l);
5560 data += l;
5561 length -= l;
5562 c->u.a.lensofar += l;
5563 }
5564 if (c->u.a.lensofar == c->u.a.totallen) {
5565 void *reply, *sentreply;
5566 int replylen;
5567 agent_query(c->u.a.message,
5568 c->u.a.totallen, &reply,
5569 &replylen);
5570 if (reply)
5571 sentreply = reply;
5572 else {
5573 /* Fake SSH_AGENT_FAILURE. */
5574 sentreply = "\0\0\0\1\5";
5575 replylen = 5;
5576 }
5577 ssh2_add_channel_data(c, sentreply, replylen);
5578 s->try_send = TRUE;
5579 if (reply)
5580 sfree(reply);
5581 sfree(c->u.a.message);
5582 c->u.a.lensofar = 0;
5583 }
5584 }
5585 bufsize = 0;
5586 break;
5587 }
5588 /*
5589 * If we are not buffering too much data,
5590 * enlarge the window again at the remote side.
5591 */
5592 if (bufsize < OUR_V2_WINSIZE)
5593 ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
5594 }
5595 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_EOF) {
5596 unsigned i = ssh2_pkt_getuint32(ssh);
5597 struct ssh_channel *c;
5598
5599 c = find234(ssh->channels, &i, ssh_channelfind);
5600 if (!c)
5601 continue; /* nonexistent channel */
5602
5603 if (c->type == CHAN_X11) {
5604 /*
5605 * Remote EOF on an X11 channel means we should
5606 * wrap up and close the channel ourselves.
5607 */
5608 x11_close(c->u.x11.s);
5609 sshfwd_close(c);
5610 } else if (c->type == CHAN_AGENT) {
5611 sshfwd_close(c);
5612 } else if (c->type == CHAN_SOCKDATA) {
5613 pfd_close(c->u.pfd.s);
5614 sshfwd_close(c);
5615 }
5616 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_CLOSE) {
5617 unsigned i = ssh2_pkt_getuint32(ssh);
5618 struct ssh_channel *c;
5619
5620 c = find234(ssh->channels, &i, ssh_channelfind);
5621 if (!c || ((int)c->remoteid) == -1) {
5622 bombout(("Received CHANNEL_CLOSE for %s channel %d\n",
5623 c ? "half-open" : "nonexistent", i));
5624 }
5625 /* Do pre-close processing on the channel. */
5626 switch (c->type) {
5627 case CHAN_MAINSESSION:
5628 break; /* nothing to see here, move along */
5629 case CHAN_X11:
5630 if (c->u.x11.s != NULL)
5631 x11_close(c->u.x11.s);
5632 sshfwd_close(c);
5633 break;
5634 case CHAN_AGENT:
5635 sshfwd_close(c);
5636 break;
5637 case CHAN_SOCKDATA:
5638 if (c->u.pfd.s != NULL)
5639 pfd_close(c->u.pfd.s);
5640 sshfwd_close(c);
5641 break;
5642 }
5643 if (c->closes == 0) {
5644 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
5645 ssh2_pkt_adduint32(ssh, c->remoteid);
5646 ssh2_pkt_send(ssh);
5647 }
5648 del234(ssh->channels, c);
5649 bufchain_clear(&c->v.v2.outbuffer);
5650 sfree(c);
5651
5652 /*
5653 * See if that was the last channel left open.
5654 */
5655 if (count234(ssh->channels) == 0) {
5656 logevent("All channels closed. Disconnecting");
5657 #if 0
5658 /*
5659 * We used to send SSH_MSG_DISCONNECT here,
5660 * because I'd believed that _every_ conforming
5661 * SSH2 connection had to end with a disconnect
5662 * being sent by at least one side; apparently
5663 * I was wrong and it's perfectly OK to
5664 * unceremoniously slam the connection shut
5665 * when you're done, and indeed OpenSSH feels
5666 * this is more polite than sending a
5667 * DISCONNECT. So now we don't.
5668 */
5669 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5670 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5671 ssh2_pkt_addstring(ssh, "All open channels closed");
5672 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5673 ssh2_pkt_send(ssh);
5674 #endif
5675 ssh_closing((Plug)ssh, NULL, 0, 0);
5676 crReturnV;
5677 }
5678 continue; /* remote sends close; ignore (FIXME) */
5679 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5680 unsigned i = ssh2_pkt_getuint32(ssh);
5681 struct ssh_channel *c;
5682 c = find234(ssh->channels, &i, ssh_channelfind);
5683 if (!c || c->closes)
5684 continue; /* nonexistent or closing channel */
5685 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5686 s->try_send = TRUE;
5687 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
5688 unsigned i = ssh2_pkt_getuint32(ssh);
5689 struct ssh_channel *c;
5690 c = find234(ssh->channels, &i, ssh_channelfind);
5691 if (!c)
5692 continue; /* nonexistent channel */
5693 if (c->type != CHAN_SOCKDATA_DORMANT)
5694 continue; /* dunno why they're confirming this */
5695 c->remoteid = ssh2_pkt_getuint32(ssh);
5696 c->type = CHAN_SOCKDATA;
5697 c->v.v2.remwindow = ssh2_pkt_getuint32(ssh);
5698 c->v.v2.remmaxpkt = ssh2_pkt_getuint32(ssh);
5699 if (c->u.pfd.s)
5700 pfd_confirm(c->u.pfd.s);
5701 if (c->closes) {
5702 /*
5703 * We have a pending close on this channel,
5704 * which we decided on before the server acked
5705 * the channel open. So now we know the
5706 * remoteid, we can close it again.
5707 */
5708 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
5709 ssh2_pkt_adduint32(ssh, c->remoteid);
5710 ssh2_pkt_send(ssh);
5711 }
5712 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN_FAILURE) {
5713 unsigned i = ssh2_pkt_getuint32(ssh);
5714 struct ssh_channel *c;
5715 c = find234(ssh->channels, &i, ssh_channelfind);
5716 if (!c)
5717 continue; /* nonexistent channel */
5718 if (c->type != CHAN_SOCKDATA_DORMANT)
5719 continue; /* dunno why they're failing this */
5720
5721 logevent("Forwarded connection refused by server");
5722
5723 pfd_close(c->u.pfd.s);
5724
5725 del234(ssh->channels, c);
5726 sfree(c);
5727 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_REQUEST) {
5728 unsigned localid;
5729 char *type;
5730 int typelen, want_reply;
5731 struct ssh_channel *c;
5732
5733 localid = ssh2_pkt_getuint32(ssh);
5734 ssh2_pkt_getstring(ssh, &type, &typelen);
5735 want_reply = ssh2_pkt_getbool(ssh);
5736
5737 /*
5738 * First, check that the channel exists. Otherwise,
5739 * we can instantly disconnect with a rude message.
5740 */
5741 c = find234(ssh->channels, &localid, ssh_channelfind);
5742 if (!c) {
5743 char buf[80];
5744 sprintf(buf, "Received channel request for nonexistent"
5745 " channel %d", localid);
5746 logevent(buf);
5747 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5748 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5749 ssh2_pkt_addstring(ssh, buf);
5750 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5751 ssh2_pkt_send(ssh);
5752 connection_fatal(ssh->frontend, "%s", buf);
5753 ssh_closing((Plug)ssh, NULL, 0, 0);
5754 crReturnV;
5755 }
5756
5757 /*
5758 * Having got the channel number, we now look at
5759 * the request type string to see if it's something
5760 * we recognise.
5761 */
5762 if (typelen == 11 && !memcmp(type, "exit-status", 11) &&
5763 c == ssh->mainchan) {
5764 /* We recognise "exit-status" on the primary channel. */
5765 char buf[100];
5766 ssh->exitcode = ssh2_pkt_getuint32(ssh);
5767 sprintf(buf, "Server sent command exit status %d",
5768 ssh->exitcode);
5769 logevent(buf);
5770 if (want_reply) {
5771 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_SUCCESS);
5772 ssh2_pkt_adduint32(ssh, c->remoteid);
5773 ssh2_pkt_send(ssh);
5774 }
5775 } else {
5776 /*
5777 * This is a channel request we don't know
5778 * about, so we now either ignore the request
5779 * or respond with CHANNEL_FAILURE, depending
5780 * on want_reply.
5781 */
5782 if (want_reply) {
5783 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_FAILURE);
5784 ssh2_pkt_adduint32(ssh, c->remoteid);
5785 ssh2_pkt_send(ssh);
5786 }
5787 }
5788 } else if (ssh->pktin.type == SSH2_MSG_GLOBAL_REQUEST) {
5789 char *type;
5790 int typelen, want_reply;
5791
5792 ssh2_pkt_getstring(ssh, &type, &typelen);
5793 want_reply = ssh2_pkt_getbool(ssh);
5794
5795 /*
5796 * We currently don't support any global requests
5797 * at all, so we either ignore the request or
5798 * respond with REQUEST_FAILURE, depending on
5799 * want_reply.
5800 */
5801 if (want_reply) {
5802 ssh2_pkt_init(ssh, SSH2_MSG_REQUEST_FAILURE);
5803 ssh2_pkt_send(ssh);
5804 }
5805 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN) {
5806 char *type;
5807 int typelen;
5808 char *peeraddr;
5809 int peeraddrlen;
5810 int port;
5811 char *error = NULL;
5812 struct ssh_channel *c;
5813 unsigned remid, winsize, pktsize;
5814 ssh2_pkt_getstring(ssh, &type, &typelen);
5815 c = snew(struct ssh_channel);
5816 c->ssh = ssh;
5817
5818 remid = ssh2_pkt_getuint32(ssh);
5819 winsize = ssh2_pkt_getuint32(ssh);
5820 pktsize = ssh2_pkt_getuint32(ssh);
5821 ssh2_pkt_getstring(ssh, &peeraddr, &peeraddrlen);
5822 port = ssh2_pkt_getuint32(ssh);
5823
5824 if (typelen == 3 && !memcmp(type, "x11", 3)) {
5825 char *addrstr = snewn(peeraddrlen+1, char);
5826 memcpy(addrstr, peeraddr, peeraddrlen);
5827 peeraddr[peeraddrlen] = '\0';
5828
5829 if (!ssh->X11_fwd_enabled)
5830 error = "X11 forwarding is not enabled";
5831 else if (x11_init(&c->u.x11.s, ssh->cfg.x11_display, c,
5832 ssh->x11auth, addrstr, port,
5833 &ssh->cfg) != NULL) {
5834 error = "Unable to open an X11 connection";
5835 } else {
5836 c->type = CHAN_X11;
5837 }
5838
5839 sfree(addrstr);
5840 } else if (typelen == 15 &&
5841 !memcmp(type, "forwarded-tcpip", 15)) {
5842 struct ssh_rportfwd pf, *realpf;
5843 char *dummy;
5844 int dummylen;
5845 ssh2_pkt_getstring(ssh, &dummy, &dummylen);/* skip address */
5846 pf.sport = ssh2_pkt_getuint32(ssh);
5847 realpf = find234(ssh->rportfwds, &pf, NULL);
5848 if (realpf == NULL) {
5849 error = "Remote port is not recognised";
5850 } else {
5851 char *e = pfd_newconnect(&c->u.pfd.s, realpf->dhost,
5852 realpf->dport, c, &ssh->cfg);
5853 logeventf(ssh, "Received remote port open request"
5854 " for %s:%d", realpf->dhost, realpf->dport);
5855 if (e != NULL) {
5856 logeventf(ssh, "Port open failed: %s", e);
5857 error = "Port open failed";
5858 } else {
5859 logevent("Forwarded port opened successfully");
5860 c->type = CHAN_SOCKDATA;
5861 }
5862 }
5863 } else if (typelen == 22 &&
5864 !memcmp(type, "auth-agent@openssh.com", 3)) {
5865 if (!ssh->agentfwd_enabled)
5866 error = "Agent forwarding is not enabled";
5867 else {
5868 c->type = CHAN_AGENT; /* identify channel type */
5869 c->u.a.lensofar = 0;
5870 }
5871 } else {
5872 error = "Unsupported channel type requested";
5873 }
5874
5875 c->remoteid = remid;
5876 if (error) {
5877 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN_FAILURE);
5878 ssh2_pkt_adduint32(ssh, c->remoteid);
5879 ssh2_pkt_adduint32(ssh, SSH2_OPEN_CONNECT_FAILED);
5880 ssh2_pkt_addstring(ssh, error);
5881 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5882 ssh2_pkt_send(ssh);
5883 sfree(c);
5884 } else {
5885 c->localid = alloc_channel_id(ssh);
5886 c->closes = 0;
5887 c->v.v2.locwindow = OUR_V2_WINSIZE;
5888 c->v.v2.remwindow = winsize;
5889 c->v.v2.remmaxpkt = pktsize;
5890 bufchain_init(&c->v.v2.outbuffer);
5891 add234(ssh->channels, c);
5892 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
5893 ssh2_pkt_adduint32(ssh, c->remoteid);
5894 ssh2_pkt_adduint32(ssh, c->localid);
5895 ssh2_pkt_adduint32(ssh, c->v.v2.locwindow);
5896 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
5897 ssh2_pkt_send(ssh);
5898 }
5899 } else {
5900 bombout(("Strange packet received: type %d", ssh->pktin.type));
5901 crReturnV;
5902 }
5903 } else {
5904 /*
5905 * We have spare data. Add it to the channel buffer.
5906 */
5907 ssh2_add_channel_data(ssh->mainchan, (char *)in, inlen);
5908 s->try_send = TRUE;
5909 }
5910 if (s->try_send) {
5911 int i;
5912 struct ssh_channel *c;
5913 /*
5914 * Try to send data on all channels if we can.
5915 */
5916 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
5917 int bufsize;
5918 if (c->closes)
5919 continue; /* don't send on closing channels */
5920 bufsize = ssh2_try_send(c);
5921 if (bufsize == 0) {
5922 switch (c->type) {
5923 case CHAN_MAINSESSION:
5924 /* stdin need not receive an unthrottle
5925 * notification since it will be polled */
5926 break;
5927 case CHAN_X11:
5928 x11_unthrottle(c->u.x11.s);
5929 break;
5930 case CHAN_AGENT:
5931 /* agent sockets are request/response and need no
5932 * buffer management */
5933 break;
5934 case CHAN_SOCKDATA:
5935 pfd_unthrottle(c->u.pfd.s);
5936 break;
5937 }
5938 }
5939 }
5940 }
5941 }
5942
5943 crFinishV;
5944 }
5945
5946 /*
5947 * Handle the top-level SSH2 protocol.
5948 */
5949 static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
5950 {
5951 if (do_ssh2_transport(ssh, in, inlen, ispkt) == 0)
5952 return;
5953 do_ssh2_authconn(ssh, in, inlen, ispkt);
5954 }
5955
5956 /*
5957 * Called to set up the connection.
5958 *
5959 * Returns an error message, or NULL on success.
5960 */
5961 static char *ssh_init(void *frontend_handle, void **backend_handle,
5962 Config *cfg,
5963 char *host, int port, char **realhost, int nodelay)
5964 {
5965 char *p;
5966 Ssh ssh;
5967
5968 ssh = snew(struct ssh_tag);
5969 ssh->cfg = *cfg; /* STRUCTURE COPY */
5970 ssh->s = NULL;
5971 ssh->cipher = NULL;
5972 ssh->v1_cipher_ctx = NULL;
5973 ssh->crcda_ctx = NULL;
5974 ssh->cscipher = NULL;
5975 ssh->cs_cipher_ctx = NULL;
5976 ssh->sccipher = NULL;
5977 ssh->sc_cipher_ctx = NULL;
5978 ssh->csmac = NULL;
5979 ssh->cs_mac_ctx = NULL;
5980 ssh->scmac = NULL;
5981 ssh->sc_mac_ctx = NULL;
5982 ssh->cscomp = NULL;
5983 ssh->cs_comp_ctx = NULL;
5984 ssh->sccomp = NULL;
5985 ssh->sc_comp_ctx = NULL;
5986 ssh->kex = NULL;
5987 ssh->kex_ctx = NULL;
5988 ssh->hostkey = NULL;
5989 ssh->exitcode = -1;
5990 ssh->state = SSH_STATE_PREPACKET;
5991 ssh->size_needed = FALSE;
5992 ssh->eof_needed = FALSE;
5993 ssh->ldisc = NULL;
5994 ssh->logctx = NULL;
5995 {
5996 static const struct Packet empty = { 0, 0, NULL, NULL, 0 };
5997 ssh->pktin = ssh->pktout = empty;
5998 }
5999 ssh->deferred_send_data = NULL;
6000 ssh->deferred_len = 0;
6001 ssh->deferred_size = 0;
6002 ssh->fallback_cmd = 0;
6003 ssh->pkt_ctx = 0;
6004 ssh->x11auth = NULL;
6005 ssh->v1_compressing = FALSE;
6006 ssh->v2_outgoing_sequence = 0;
6007 ssh->ssh1_rdpkt_crstate = 0;
6008 ssh->ssh2_rdpkt_crstate = 0;
6009 ssh->do_ssh_init_crstate = 0;
6010 ssh->ssh_gotdata_crstate = 0;
6011 ssh->ssh1_protocol_crstate = 0;
6012 ssh->do_ssh1_login_crstate = 0;
6013 ssh->do_ssh2_transport_crstate = 0;
6014 ssh->do_ssh2_authconn_crstate = 0;
6015 ssh->do_ssh_init_state = NULL;
6016 ssh->do_ssh1_login_state = NULL;
6017 ssh->do_ssh2_transport_state = NULL;
6018 ssh->do_ssh2_authconn_state = NULL;
6019 ssh->mainchan = NULL;
6020 ssh->throttled_all = 0;
6021 ssh->v1_stdout_throttling = 0;
6022
6023 *backend_handle = ssh;
6024
6025 #ifdef MSCRYPTOAPI
6026 if (crypto_startup() == 0)
6027 return "Microsoft high encryption pack not installed!";
6028 #endif
6029
6030 ssh->frontend = frontend_handle;
6031 ssh->term_width = ssh->cfg.width;
6032 ssh->term_height = ssh->cfg.height;
6033
6034 ssh->channels = NULL;
6035 ssh->rportfwds = NULL;
6036
6037 ssh->send_ok = 0;
6038 ssh->editing = 0;
6039 ssh->echoing = 0;
6040 ssh->v1_throttle_count = 0;
6041 ssh->overall_bufsize = 0;
6042 ssh->fallback_cmd = 0;
6043
6044 ssh->protocol = NULL;
6045
6046 p = connect_to_host(ssh, host, port, realhost, nodelay);
6047 if (p != NULL)
6048 return p;
6049
6050 return NULL;
6051 }
6052
6053 static void ssh_free(void *handle)
6054 {
6055 Ssh ssh = (Ssh) handle;
6056 struct ssh_channel *c;
6057 struct ssh_rportfwd *pf;
6058
6059 if (ssh->v1_cipher_ctx)
6060 ssh->cipher->free_context(ssh->v1_cipher_ctx);
6061 if (ssh->cs_cipher_ctx)
6062 ssh->cscipher->free_context(ssh->cs_cipher_ctx);
6063 if (ssh->sc_cipher_ctx)
6064 ssh->sccipher->free_context(ssh->sc_cipher_ctx);
6065 if (ssh->cs_mac_ctx)
6066 ssh->csmac->free_context(ssh->cs_mac_ctx);
6067 if (ssh->sc_mac_ctx)
6068 ssh->scmac->free_context(ssh->sc_mac_ctx);
6069 if (ssh->cs_comp_ctx)
6070 ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
6071 if (ssh->sc_comp_ctx)
6072 ssh->sccomp->compress_cleanup(ssh->sc_comp_ctx);
6073 if (ssh->kex_ctx)
6074 dh_cleanup(ssh->kex_ctx);
6075 sfree(ssh->savedhost);
6076
6077 if (ssh->channels) {
6078 while ((c = delpos234(ssh->channels, 0)) != NULL) {
6079 switch (c->type) {
6080 case CHAN_X11:
6081 if (c->u.x11.s != NULL)
6082 x11_close(c->u.x11.s);
6083 break;
6084 case CHAN_SOCKDATA:
6085 if (c->u.pfd.s != NULL)
6086 pfd_close(c->u.pfd.s);
6087 break;
6088 }
6089 sfree(c);
6090 }
6091 freetree234(ssh->channels);
6092 }
6093
6094 if (ssh->rportfwds) {
6095 while ((pf = delpos234(ssh->rportfwds, 0)) != NULL)
6096 sfree(pf);
6097 freetree234(ssh->rportfwds);
6098 }
6099 sfree(ssh->deferred_send_data);
6100 if (ssh->x11auth)
6101 x11_free_auth(ssh->x11auth);
6102 sfree(ssh->do_ssh_init_state);
6103 sfree(ssh->do_ssh1_login_state);
6104 sfree(ssh->do_ssh2_transport_state);
6105 sfree(ssh->do_ssh2_authconn_state);
6106
6107 if (ssh->s)
6108 sk_close(ssh->s);
6109 sfree(ssh);
6110 }
6111
6112 /*
6113 * Reconfigure the SSH backend.
6114 *
6115 * Currently, this function does nothing very useful. In future,
6116 * however, we could do some handy things with it. For example, we
6117 * could make the port forwarding configurer active in the Change
6118 * Settings box, and this routine could close down existing
6119 * forwardings and open up new ones in response to changes.
6120 */
6121 static void ssh_reconfig(void *handle, Config *cfg)
6122 {
6123 Ssh ssh = (Ssh) handle;
6124 ssh->cfg = *cfg; /* STRUCTURE COPY */
6125 }
6126
6127 /*
6128 * Called to send data down the Telnet connection.
6129 */
6130 static int ssh_send(void *handle, char *buf, int len)
6131 {
6132 Ssh ssh = (Ssh) handle;
6133
6134 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
6135 return 0;
6136
6137 ssh->protocol(ssh, (unsigned char *)buf, len, 0);
6138
6139 return ssh_sendbuffer(ssh);
6140 }
6141
6142 /*
6143 * Called to query the current amount of buffered stdin data.
6144 */
6145 static int ssh_sendbuffer(void *handle)
6146 {
6147 Ssh ssh = (Ssh) handle;
6148 int override_value;
6149
6150 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
6151 return 0;
6152
6153 /*
6154 * If the SSH socket itself has backed up, add the total backup
6155 * size on that to any individual buffer on the stdin channel.
6156 */
6157 override_value = 0;
6158 if (ssh->throttled_all)
6159 override_value = ssh->overall_bufsize;
6160
6161 if (ssh->version == 1) {
6162 return override_value;
6163 } else if (ssh->version == 2) {
6164 if (!ssh->mainchan || ssh->mainchan->closes > 0)
6165 return override_value;
6166 else
6167 return (override_value +
6168 bufchain_size(&ssh->mainchan->v.v2.outbuffer));
6169 }
6170
6171 return 0;
6172 }
6173
6174 /*
6175 * Called to set the size of the window from SSH's POV.
6176 */
6177 static void ssh_size(void *handle, int width, int height)
6178 {
6179 Ssh ssh = (Ssh) handle;
6180
6181 ssh->term_width = width;
6182 ssh->term_height = height;
6183
6184 switch (ssh->state) {
6185 case SSH_STATE_BEFORE_SIZE:
6186 case SSH_STATE_PREPACKET:
6187 case SSH_STATE_CLOSED:
6188 break; /* do nothing */
6189 case SSH_STATE_INTERMED:
6190 ssh->size_needed = TRUE; /* buffer for later */
6191 break;
6192 case SSH_STATE_SESSION:
6193 if (!ssh->cfg.nopty) {
6194 if (ssh->version == 1) {
6195 send_packet(ssh, SSH1_CMSG_WINDOW_SIZE,
6196 PKT_INT, ssh->term_height,
6197 PKT_INT, ssh->term_width,
6198 PKT_INT, 0, PKT_INT, 0, PKT_END);
6199 } else {
6200 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
6201 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
6202 ssh2_pkt_addstring(ssh, "window-change");
6203 ssh2_pkt_addbool(ssh, 0);
6204 ssh2_pkt_adduint32(ssh, ssh->term_width);
6205 ssh2_pkt_adduint32(ssh, ssh->term_height);
6206 ssh2_pkt_adduint32(ssh, 0);
6207 ssh2_pkt_adduint32(ssh, 0);
6208 ssh2_pkt_send(ssh);
6209 }
6210 }
6211 break;
6212 }
6213 }
6214
6215 /*
6216 * Send Telnet special codes. TS_EOF is useful for `plink', so you
6217 * can send an EOF and collect resulting output (e.g. `plink
6218 * hostname sort').
6219 */
6220 static void ssh_special(void *handle, Telnet_Special code)
6221 {
6222 Ssh ssh = (Ssh) handle;
6223
6224 if (code == TS_EOF) {
6225 if (ssh->state != SSH_STATE_SESSION) {
6226 /*
6227 * Buffer the EOF in case we are pre-SESSION, so we can
6228 * send it as soon as we reach SESSION.
6229 */
6230 if (code == TS_EOF)
6231 ssh->eof_needed = TRUE;
6232 return;
6233 }
6234 if (ssh->version == 1) {
6235 send_packet(ssh, SSH1_CMSG_EOF, PKT_END);
6236 } else {
6237 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_EOF);
6238 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
6239 ssh2_pkt_send(ssh);
6240 }
6241 logevent("Sent EOF message");
6242 } else if (code == TS_PING) {
6243 if (ssh->state == SSH_STATE_CLOSED
6244 || ssh->state == SSH_STATE_PREPACKET) return;
6245 if (ssh->version == 1) {
6246 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE))
6247 send_packet(ssh, SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
6248 } else {
6249 ssh2_pkt_init(ssh, SSH2_MSG_IGNORE);
6250 ssh2_pkt_addstring_start(ssh);
6251 ssh2_pkt_send(ssh);
6252 }
6253 } else {
6254 /* do nothing */
6255 }
6256 }
6257
6258 void *new_sock_channel(void *handle, Socket s)
6259 {
6260 Ssh ssh = (Ssh) handle;
6261 struct ssh_channel *c;
6262 c = snew(struct ssh_channel);
6263 c->ssh = ssh;
6264
6265 if (c) {
6266 c->remoteid = -1; /* to be set when open confirmed */
6267 c->localid = alloc_channel_id(ssh);
6268 c->closes = 0;
6269 c->type = CHAN_SOCKDATA_DORMANT;/* identify channel type */
6270 c->u.pfd.s = s;
6271 bufchain_init(&c->v.v2.outbuffer);
6272 add234(ssh->channels, c);
6273 }
6274 return c;
6275 }
6276
6277 /*
6278 * This is called when stdout/stderr (the entity to which
6279 * from_backend sends data) manages to clear some backlog.
6280 */
6281 static void ssh_unthrottle(void *handle, int bufsize)
6282 {
6283 Ssh ssh = (Ssh) handle;
6284 if (ssh->version == 1) {
6285 if (ssh->v1_stdout_throttling && bufsize < SSH1_BUFFER_LIMIT) {
6286 ssh->v1_stdout_throttling = 0;
6287 ssh1_throttle(ssh, -1);
6288 }
6289 } else {
6290 if (ssh->mainchan && ssh->mainchan->closes == 0)
6291 ssh2_set_window(ssh->mainchan, OUR_V2_WINSIZE - bufsize);
6292 }
6293 }
6294
6295 void ssh_send_port_open(void *channel, char *hostname, int port, char *org)
6296 {
6297 struct ssh_channel *c = (struct ssh_channel *)channel;
6298 Ssh ssh = c->ssh;
6299
6300 logeventf(ssh, "Opening forwarded connection to %s:%d", hostname, port);
6301
6302 if (ssh->version == 1) {
6303 send_packet(ssh, SSH1_MSG_PORT_OPEN,
6304 PKT_INT, c->localid,
6305 PKT_STR, hostname,
6306 PKT_INT, port,
6307 //PKT_STR, <org:orgport>,
6308 PKT_END);
6309 } else {
6310 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN);
6311 ssh2_pkt_addstring(ssh, "direct-tcpip");
6312 ssh2_pkt_adduint32(ssh, c->localid);
6313 c->v.v2.locwindow = OUR_V2_WINSIZE;
6314 ssh2_pkt_adduint32(ssh, c->v.v2.locwindow);/* our window size */
6315 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
6316 ssh2_pkt_addstring(ssh, hostname);
6317 ssh2_pkt_adduint32(ssh, port);
6318 /*
6319 * We make up values for the originator data; partly it's
6320 * too much hassle to keep track, and partly I'm not
6321 * convinced the server should be told details like that
6322 * about my local network configuration.
6323 */
6324 ssh2_pkt_addstring(ssh, "client-side-connection");
6325 ssh2_pkt_adduint32(ssh, 0);
6326 ssh2_pkt_send(ssh);
6327 }
6328 }
6329
6330
6331 static Socket ssh_socket(void *handle)
6332 {
6333 Ssh ssh = (Ssh) handle;
6334 return ssh->s;
6335 }
6336
6337 static int ssh_sendok(void *handle)
6338 {
6339 Ssh ssh = (Ssh) handle;
6340 return ssh->send_ok;
6341 }
6342
6343 static int ssh_ldisc(void *handle, int option)
6344 {
6345 Ssh ssh = (Ssh) handle;
6346 if (option == LD_ECHO)
6347 return ssh->echoing;
6348 if (option == LD_EDIT)
6349 return ssh->editing;
6350 return FALSE;
6351 }
6352
6353 static void ssh_provide_ldisc(void *handle, void *ldisc)
6354 {
6355 Ssh ssh = (Ssh) handle;
6356 ssh->ldisc = ldisc;
6357 }
6358
6359 static void ssh_provide_logctx(void *handle, void *logctx)
6360 {
6361 Ssh ssh = (Ssh) handle;
6362 ssh->logctx = logctx;
6363 }
6364
6365 static int ssh_return_exitcode(void *handle)
6366 {
6367 Ssh ssh = (Ssh) handle;
6368 if (ssh->s != NULL)
6369 return -1;
6370 else
6371 return (ssh->exitcode >= 0 ? ssh->exitcode : 0);
6372 }
6373
6374 /*
6375 * Gross hack: pscp will try to start SFTP but fall back to scp1 if
6376 * that fails. This variable is the means by which scp.c can reach
6377 * into the SSH code and find out which one it got.
6378 */
6379 extern int ssh_fallback_cmd(void *handle)
6380 {
6381 Ssh ssh = (Ssh) handle;
6382 return ssh->fallback_cmd;
6383 }
6384
6385 Backend ssh_backend = {
6386 ssh_init,
6387 ssh_free,
6388 ssh_reconfig,
6389 ssh_send,
6390 ssh_sendbuffer,
6391 ssh_size,
6392 ssh_special,
6393 ssh_socket,
6394 ssh_return_exitcode,
6395 ssh_sendok,
6396 ssh_ldisc,
6397 ssh_provide_ldisc,
6398 ssh_provide_logctx,
6399 ssh_unthrottle,
6400 22
6401 };
Local modifications for Simon Tatham's `PuTTY' SSH client and terminal emulator