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Report details in Event Log when receiving SSH2_MSG_CHANNEL_OPEN_FAILURE.
[sgt/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 static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt);
326 static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt);
327
328 /*
329 * Buffer management constants. There are several of these for
330 * various different purposes:
331 *
332 * - SSH1_BUFFER_LIMIT is the amount of backlog that must build up
333 * on a local data stream before we throttle the whole SSH
334 * connection (in SSH1 only). Throttling the whole connection is
335 * pretty drastic so we set this high in the hope it won't
336 * happen very often.
337 *
338 * - SSH_MAX_BACKLOG is the amount of backlog that must build up
339 * on the SSH connection itself before we defensively throttle
340 * _all_ local data streams. This is pretty drastic too (though
341 * thankfully unlikely in SSH2 since the window mechanism should
342 * ensure that the server never has any need to throttle its end
343 * of the connection), so we set this high as well.
344 *
345 * - OUR_V2_WINSIZE is the maximum window size we present on SSH2
346 * channels.
347 */
348
349 #define SSH1_BUFFER_LIMIT 32768
350 #define SSH_MAX_BACKLOG 32768
351 #define OUR_V2_WINSIZE 16384
352
353 const static struct ssh_kex *kex_algs[] = {
354 &ssh_diffiehellman_gex,
355 &ssh_diffiehellman
356 };
357
358 const static struct ssh_signkey *hostkey_algs[] = { &ssh_rsa, &ssh_dss };
359
360 static void *nullmac_make_context(void)
361 {
362 return NULL;
363 }
364 static void nullmac_free_context(void *handle)
365 {
366 }
367 static void nullmac_key(void *handle, unsigned char *key)
368 {
369 }
370 static void nullmac_generate(void *handle, unsigned char *blk, int len,
371 unsigned long seq)
372 {
373 }
374 static int nullmac_verify(void *handle, unsigned char *blk, int len,
375 unsigned long seq)
376 {
377 return 1;
378 }
379 const static struct ssh_mac ssh_mac_none = {
380 nullmac_make_context, nullmac_free_context, nullmac_key,
381 nullmac_generate, nullmac_verify, "none", 0
382 };
383 const static struct ssh_mac *macs[] = {
384 &ssh_sha1, &ssh_md5, &ssh_mac_none
385 };
386 const static struct ssh_mac *buggymacs[] = {
387 &ssh_sha1_buggy, &ssh_md5, &ssh_mac_none
388 };
389
390 static void *ssh_comp_none_init(void)
391 {
392 return NULL;
393 }
394 static void ssh_comp_none_cleanup(void *handle)
395 {
396 }
397 static int ssh_comp_none_block(void *handle, unsigned char *block, int len,
398 unsigned char **outblock, int *outlen)
399 {
400 return 0;
401 }
402 static int ssh_comp_none_disable(void *handle)
403 {
404 return 0;
405 }
406 const static struct ssh_compress ssh_comp_none = {
407 "none",
408 ssh_comp_none_init, ssh_comp_none_cleanup, ssh_comp_none_block,
409 ssh_comp_none_init, ssh_comp_none_cleanup, ssh_comp_none_block,
410 ssh_comp_none_disable, NULL
411 };
412 extern const struct ssh_compress ssh_zlib;
413 const static struct ssh_compress *compressions[] = {
414 &ssh_zlib, &ssh_comp_none
415 };
416
417 enum { /* channel types */
418 CHAN_MAINSESSION,
419 CHAN_X11,
420 CHAN_AGENT,
421 CHAN_SOCKDATA,
422 CHAN_SOCKDATA_DORMANT /* one the remote hasn't confirmed */
423 };
424
425 /*
426 * 2-3-4 tree storing channels.
427 */
428 struct ssh_channel {
429 Ssh ssh; /* pointer back to main context */
430 unsigned remoteid, localid;
431 int type;
432 /*
433 * In SSH1, this value contains four bits:
434 *
435 * 1 We have sent SSH1_MSG_CHANNEL_CLOSE.
436 * 2 We have sent SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION.
437 * 4 We have received SSH1_MSG_CHANNEL_CLOSE.
438 * 8 We have received SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION.
439 *
440 * A channel is completely finished with when all four bits are set.
441 */
442 int closes;
443 union {
444 struct ssh1_data_channel {
445 int throttling;
446 } v1;
447 struct ssh2_data_channel {
448 bufchain outbuffer;
449 unsigned remwindow, remmaxpkt;
450 unsigned locwindow;
451 } v2;
452 } v;
453 union {
454 struct ssh_agent_channel {
455 unsigned char *message;
456 unsigned char msglen[4];
457 int lensofar, totallen;
458 } a;
459 struct ssh_x11_channel {
460 Socket s;
461 } x11;
462 struct ssh_pfd_channel {
463 Socket s;
464 } pfd;
465 } u;
466 };
467
468 /*
469 * 2-3-4 tree storing remote->local port forwardings. SSH 1 and SSH
470 * 2 use this structure in different ways, reflecting SSH 2's
471 * altogether saner approach to port forwarding.
472 *
473 * In SSH 1, you arrange a remote forwarding by sending the server
474 * the remote port number, and the local destination host:port.
475 * When a connection comes in, the server sends you back that
476 * host:port pair, and you connect to it. This is a ready-made
477 * security hole if you're not on the ball: a malicious server
478 * could send you back _any_ host:port pair, so if you trustingly
479 * connect to the address it gives you then you've just opened the
480 * entire inside of your corporate network just by connecting
481 * through it to a dodgy SSH server. Hence, we must store a list of
482 * host:port pairs we _are_ trying to forward to, and reject a
483 * connection request from the server if it's not in the list.
484 *
485 * In SSH 2, each side of the connection minds its own business and
486 * doesn't send unnecessary information to the other. You arrange a
487 * remote forwarding by sending the server just the remote port
488 * number. When a connection comes in, the server tells you which
489 * of its ports was connected to; and _you_ have to remember what
490 * local host:port pair went with that port number.
491 *
492 * Hence: in SSH 1 this structure stores host:port pairs we intend
493 * to allow connections to, and is indexed by those host:port
494 * pairs. In SSH 2 it stores a mapping from source port to
495 * destination host:port pair, and is indexed by source port.
496 */
497 struct ssh_rportfwd {
498 unsigned sport, dport;
499 char dhost[256];
500 };
501
502 struct Packet {
503 long length;
504 int type;
505 unsigned char *data;
506 unsigned char *body;
507 long savedpos;
508 long maxlen;
509 };
510
511 static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt);
512 static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt);
513 static void ssh_size(void *handle, int width, int height);
514 static void ssh_special(void *handle, Telnet_Special);
515 static int ssh2_try_send(struct ssh_channel *c);
516 static void ssh2_add_channel_data(struct ssh_channel *c, char *buf, int len);
517 static void ssh_throttle_all(Ssh ssh, int enable, int bufsize);
518 static void ssh2_set_window(struct ssh_channel *c, unsigned newwin);
519 static int ssh_sendbuffer(void *handle);
520 static void ssh_do_close(Ssh ssh);
521
522 struct rdpkt1_state_tag {
523 long len, pad, biglen, to_read;
524 unsigned long realcrc, gotcrc;
525 unsigned char *p;
526 int i;
527 int chunk;
528 };
529
530 struct rdpkt2_state_tag {
531 long len, pad, payload, packetlen, maclen;
532 int i;
533 int cipherblk;
534 unsigned long incoming_sequence;
535 };
536
537 struct ssh_tag {
538 const struct plug_function_table *fn;
539 /* the above field _must_ be first in the structure */
540
541 SHA_State exhash, exhashbase;
542
543 Socket s;
544
545 void *ldisc;
546 void *logctx;
547
548 unsigned char session_key[32];
549 int v1_compressing;
550 int v1_remote_protoflags;
551 int v1_local_protoflags;
552 int agentfwd_enabled;
553 int X11_fwd_enabled;
554 int remote_bugs;
555 const struct ssh_cipher *cipher;
556 void *v1_cipher_ctx;
557 void *crcda_ctx;
558 const struct ssh2_cipher *cscipher, *sccipher;
559 void *cs_cipher_ctx, *sc_cipher_ctx;
560 const struct ssh_mac *csmac, *scmac;
561 void *cs_mac_ctx, *sc_mac_ctx;
562 const struct ssh_compress *cscomp, *sccomp;
563 void *cs_comp_ctx, *sc_comp_ctx;
564 const struct ssh_kex *kex;
565 const struct ssh_signkey *hostkey;
566 unsigned char v2_session_id[20];
567 void *kex_ctx;
568
569 char *savedhost;
570 int savedport;
571 int send_ok;
572 int echoing, editing;
573
574 void *frontend;
575
576 int ospeed, ispeed; /* temporaries */
577 int term_width, term_height;
578
579 tree234 *channels; /* indexed by local id */
580 struct ssh_channel *mainchan; /* primary session channel */
581 int exitcode;
582
583 tree234 *rportfwds;
584
585 enum {
586 SSH_STATE_PREPACKET,
587 SSH_STATE_BEFORE_SIZE,
588 SSH_STATE_INTERMED,
589 SSH_STATE_SESSION,
590 SSH_STATE_CLOSED
591 } state;
592
593 int size_needed, eof_needed;
594
595 struct Packet pktin;
596 struct Packet pktout;
597 unsigned char *deferred_send_data;
598 int deferred_len, deferred_size;
599
600 /*
601 * Gross hack: pscp will try to start SFTP but fall back to
602 * scp1 if that fails. This variable is the means by which
603 * scp.c can reach into the SSH code and find out which one it
604 * got.
605 */
606 int fallback_cmd;
607
608 /*
609 * Used for username and password input.
610 */
611 char *userpass_input_buffer;
612 int userpass_input_buflen;
613 int userpass_input_bufpos;
614 int userpass_input_echo;
615
616 char *portfwd_strptr;
617 int pkt_ctx;
618
619 void *x11auth;
620
621 int version;
622 int v1_throttle_count;
623 int overall_bufsize;
624 int throttled_all;
625 int v1_stdout_throttling;
626 int v2_outgoing_sequence;
627
628 int ssh1_rdpkt_crstate;
629 int ssh2_rdpkt_crstate;
630 int do_ssh_init_crstate;
631 int ssh_gotdata_crstate;
632 int ssh1_protocol_crstate;
633 int do_ssh1_login_crstate;
634 int do_ssh2_transport_crstate;
635 int do_ssh2_authconn_crstate;
636
637 void *do_ssh_init_state;
638 void *do_ssh1_login_state;
639 void *do_ssh2_transport_state;
640 void *do_ssh2_authconn_state;
641
642 struct rdpkt1_state_tag rdpkt1_state;
643 struct rdpkt2_state_tag rdpkt2_state;
644
645 void (*protocol) (Ssh ssh, unsigned char *in, int inlen, int ispkt);
646 int (*s_rdpkt) (Ssh ssh, unsigned char **data, int *datalen);
647
648 /*
649 * We maintain a full _copy_ of a Config structure here, not
650 * merely a pointer to it. That way, when we're passed a new
651 * one for reconfiguration, we can check the differences and
652 * potentially reconfigure port forwardings etc in mid-session.
653 */
654 Config cfg;
655
656 /*
657 * Used to transfer data back from async agent callbacks.
658 */
659 void *agent_response;
660 int agent_response_len;
661 };
662
663 #define logevent(s) logevent(ssh->frontend, s)
664
665 /* logevent, only printf-formatted. */
666 static void logeventf(Ssh ssh, const char *fmt, ...)
667 {
668 va_list ap;
669 char *buf;
670
671 va_start(ap, fmt);
672 buf = dupvprintf(fmt, ap);
673 va_end(ap);
674 logevent(buf);
675 sfree(buf);
676 }
677
678 #define bombout(msg) \
679 do { \
680 char *text = dupprintf msg; \
681 ssh_do_close(ssh); \
682 logevent(text); \
683 connection_fatal(ssh->frontend, "%s", text); \
684 sfree(text); \
685 } while (0)
686
687 static int ssh_channelcmp(void *av, void *bv)
688 {
689 struct ssh_channel *a = (struct ssh_channel *) av;
690 struct ssh_channel *b = (struct ssh_channel *) bv;
691 if (a->localid < b->localid)
692 return -1;
693 if (a->localid > b->localid)
694 return +1;
695 return 0;
696 }
697 static int ssh_channelfind(void *av, void *bv)
698 {
699 unsigned *a = (unsigned *) av;
700 struct ssh_channel *b = (struct ssh_channel *) bv;
701 if (*a < b->localid)
702 return -1;
703 if (*a > b->localid)
704 return +1;
705 return 0;
706 }
707
708 static int ssh_rportcmp_ssh1(void *av, void *bv)
709 {
710 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
711 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
712 int i;
713 if ( (i = strcmp(a->dhost, b->dhost)) != 0)
714 return i < 0 ? -1 : +1;
715 if (a->dport > b->dport)
716 return +1;
717 if (a->dport < b->dport)
718 return -1;
719 return 0;
720 }
721
722 static int ssh_rportcmp_ssh2(void *av, void *bv)
723 {
724 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
725 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
726
727 if (a->sport > b->sport)
728 return +1;
729 if (a->sport < b->sport)
730 return -1;
731 return 0;
732 }
733
734 static int alloc_channel_id(Ssh ssh)
735 {
736 const unsigned CHANNEL_NUMBER_OFFSET = 256;
737 unsigned low, high, mid;
738 int tsize;
739 struct ssh_channel *c;
740
741 /*
742 * First-fit allocation of channel numbers: always pick the
743 * lowest unused one. To do this, binary-search using the
744 * counted B-tree to find the largest channel ID which is in a
745 * contiguous sequence from the beginning. (Precisely
746 * everything in that sequence must have ID equal to its tree
747 * index plus CHANNEL_NUMBER_OFFSET.)
748 */
749 tsize = count234(ssh->channels);
750
751 low = -1;
752 high = tsize;
753 while (high - low > 1) {
754 mid = (high + low) / 2;
755 c = index234(ssh->channels, mid);
756 if (c->localid == mid + CHANNEL_NUMBER_OFFSET)
757 low = mid; /* this one is fine */
758 else
759 high = mid; /* this one is past it */
760 }
761 /*
762 * Now low points to either -1, or the tree index of the
763 * largest ID in the initial sequence.
764 */
765 {
766 unsigned i = low + 1 + CHANNEL_NUMBER_OFFSET;
767 assert(NULL == find234(ssh->channels, &i, ssh_channelfind));
768 }
769 return low + 1 + CHANNEL_NUMBER_OFFSET;
770 }
771
772 static void c_write(Ssh ssh, const char *buf, int len)
773 {
774 if ((flags & FLAG_STDERR)) {
775 int i;
776 for (i = 0; i < len; i++)
777 if (buf[i] != '\r')
778 fputc(buf[i], stderr);
779 return;
780 }
781 from_backend(ssh->frontend, 1, buf, len);
782 }
783
784 static void c_write_untrusted(Ssh ssh, const char *buf, int len)
785 {
786 int i;
787 for (i = 0; i < len; i++) {
788 if (buf[i] == '\n')
789 c_write(ssh, "\r\n", 2);
790 else if ((buf[i] & 0x60) || (buf[i] == '\r'))
791 c_write(ssh, buf + i, 1);
792 }
793 }
794
795 static void c_write_str(Ssh ssh, const char *buf)
796 {
797 c_write(ssh, buf, strlen(buf));
798 }
799
800 /*
801 * Collect incoming data in the incoming packet buffer.
802 * Decipher and verify the packet when it is completely read.
803 * Drop SSH1_MSG_DEBUG and SSH1_MSG_IGNORE packets.
804 * Update the *data and *datalen variables.
805 * Return the additional nr of bytes needed, or 0 when
806 * a complete packet is available.
807 */
808 static int ssh1_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
809 {
810 struct rdpkt1_state_tag *st = &ssh->rdpkt1_state;
811
812 crBegin(ssh->ssh1_rdpkt_crstate);
813
814 next_packet:
815
816 ssh->pktin.type = 0;
817 ssh->pktin.length = 0;
818
819 for (st->i = st->len = 0; st->i < 4; st->i++) {
820 while ((*datalen) == 0)
821 crReturn(4 - st->i);
822 st->len = (st->len << 8) + **data;
823 (*data)++, (*datalen)--;
824 }
825
826 st->pad = 8 - (st->len % 8);
827 st->biglen = st->len + st->pad;
828 ssh->pktin.length = st->len - 5;
829
830 if (st->biglen < 0) {
831 bombout(("Extremely large packet length from server suggests"
832 " data stream corruption"));
833 crStop(0);
834 }
835
836 if (ssh->pktin.maxlen < st->biglen) {
837 ssh->pktin.maxlen = st->biglen;
838 ssh->pktin.data = sresize(ssh->pktin.data, st->biglen + APIEXTRA,
839 unsigned char);
840 }
841
842 st->to_read = st->biglen;
843 st->p = ssh->pktin.data;
844 while (st->to_read > 0) {
845 st->chunk = st->to_read;
846 while ((*datalen) == 0)
847 crReturn(st->to_read);
848 if (st->chunk > (*datalen))
849 st->chunk = (*datalen);
850 memcpy(st->p, *data, st->chunk);
851 *data += st->chunk;
852 *datalen -= st->chunk;
853 st->p += st->chunk;
854 st->to_read -= st->chunk;
855 }
856
857 if (ssh->cipher && detect_attack(ssh->crcda_ctx, ssh->pktin.data,
858 st->biglen, NULL)) {
859 bombout(("Network attack (CRC compensation) detected!"));
860 crStop(0);
861 }
862
863 if (ssh->cipher)
864 ssh->cipher->decrypt(ssh->v1_cipher_ctx, ssh->pktin.data, st->biglen);
865
866 st->realcrc = crc32_compute(ssh->pktin.data, st->biglen - 4);
867 st->gotcrc = GET_32BIT(ssh->pktin.data + st->biglen - 4);
868 if (st->gotcrc != st->realcrc) {
869 bombout(("Incorrect CRC received on packet"));
870 crStop(0);
871 }
872
873 ssh->pktin.body = ssh->pktin.data + st->pad + 1;
874 ssh->pktin.savedpos = 0;
875
876 if (ssh->v1_compressing) {
877 unsigned char *decompblk;
878 int decomplen;
879 if (!zlib_decompress_block(ssh->sc_comp_ctx,
880 ssh->pktin.body - 1, ssh->pktin.length + 1,
881 &decompblk, &decomplen)) {
882 bombout(("Zlib decompression encountered invalid data"));
883 crStop(0);
884 }
885
886 if (ssh->pktin.maxlen < st->pad + decomplen) {
887 ssh->pktin.maxlen = st->pad + decomplen;
888 ssh->pktin.data = sresize(ssh->pktin.data,
889 ssh->pktin.maxlen + APIEXTRA,
890 unsigned char);
891 ssh->pktin.body = ssh->pktin.data + st->pad + 1;
892 }
893
894 memcpy(ssh->pktin.body - 1, decompblk, decomplen);
895 sfree(decompblk);
896 ssh->pktin.length = decomplen - 1;
897 }
898
899 ssh->pktin.type = ssh->pktin.body[-1];
900
901 if (ssh->logctx)
902 log_packet(ssh->logctx,
903 PKT_INCOMING, ssh->pktin.type,
904 ssh1_pkt_type(ssh->pktin.type),
905 ssh->pktin.body, ssh->pktin.length);
906
907 if (ssh->pktin.type == SSH1_SMSG_STDOUT_DATA ||
908 ssh->pktin.type == SSH1_SMSG_STDERR_DATA ||
909 ssh->pktin.type == SSH1_MSG_DEBUG ||
910 ssh->pktin.type == SSH1_SMSG_AUTH_TIS_CHALLENGE ||
911 ssh->pktin.type == SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
912 long stringlen = GET_32BIT(ssh->pktin.body);
913 if (stringlen + 4 != ssh->pktin.length) {
914 bombout(("Received data packet with bogus string length"));
915 crStop(0);
916 }
917 }
918
919 if (ssh->pktin.type == SSH1_MSG_DEBUG) {
920 /* log debug message */
921 char buf[512];
922 int stringlen = GET_32BIT(ssh->pktin.body);
923 strcpy(buf, "Remote debug message: ");
924 if (stringlen > 480)
925 stringlen = 480;
926 memcpy(buf + 8, ssh->pktin.body + 4, stringlen);
927 buf[8 + stringlen] = '\0';
928 logevent(buf);
929 goto next_packet;
930 } else if (ssh->pktin.type == SSH1_MSG_IGNORE) {
931 /* do nothing */
932 goto next_packet;
933 }
934
935 if (ssh->pktin.type == SSH1_MSG_DISCONNECT) {
936 /* log reason code in disconnect message */
937 char buf[256];
938 unsigned msglen = GET_32BIT(ssh->pktin.body);
939 unsigned nowlen;
940 strcpy(buf, "Remote sent disconnect: ");
941 nowlen = strlen(buf);
942 if (msglen > sizeof(buf) - nowlen - 1)
943 msglen = sizeof(buf) - nowlen - 1;
944 memcpy(buf + nowlen, ssh->pktin.body + 4, msglen);
945 buf[nowlen + msglen] = '\0';
946 /* logevent(buf); (this is now done within the bombout macro) */
947 bombout(("Server sent disconnect message:\n\"%s\"", buf+nowlen));
948 crStop(0);
949 }
950
951 crFinish(0);
952 }
953
954 static int ssh2_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
955 {
956 struct rdpkt2_state_tag *st = &ssh->rdpkt2_state;
957
958 crBegin(ssh->ssh2_rdpkt_crstate);
959
960 next_packet:
961 ssh->pktin.type = 0;
962 ssh->pktin.length = 0;
963 if (ssh->sccipher)
964 st->cipherblk = ssh->sccipher->blksize;
965 else
966 st->cipherblk = 8;
967 if (st->cipherblk < 8)
968 st->cipherblk = 8;
969
970 if (ssh->pktin.maxlen < st->cipherblk) {
971 ssh->pktin.maxlen = st->cipherblk;
972 ssh->pktin.data = sresize(ssh->pktin.data, st->cipherblk + APIEXTRA,
973 unsigned char);
974 }
975
976 /*
977 * Acquire and decrypt the first block of the packet. This will
978 * contain the length and padding details.
979 */
980 for (st->i = st->len = 0; st->i < st->cipherblk; st->i++) {
981 while ((*datalen) == 0)
982 crReturn(st->cipherblk - st->i);
983 ssh->pktin.data[st->i] = *(*data)++;
984 (*datalen)--;
985 }
986
987 if (ssh->sccipher)
988 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
989 ssh->pktin.data, st->cipherblk);
990
991 /*
992 * Now get the length and padding figures.
993 */
994 st->len = GET_32BIT(ssh->pktin.data);
995 st->pad = ssh->pktin.data[4];
996
997 /*
998 * _Completely_ silly lengths should be stomped on before they
999 * do us any more damage.
1000 */
1001 if (st->len < 0 || st->pad < 0 || st->len + st->pad < 0) {
1002 bombout(("Incoming packet was garbled on decryption"));
1003 crStop(0);
1004 }
1005
1006 /*
1007 * This enables us to deduce the payload length.
1008 */
1009 st->payload = st->len - st->pad - 1;
1010
1011 ssh->pktin.length = st->payload + 5;
1012
1013 /*
1014 * So now we can work out the total packet length.
1015 */
1016 st->packetlen = st->len + 4;
1017 st->maclen = ssh->scmac ? ssh->scmac->len : 0;
1018
1019 /*
1020 * Adjust memory allocation if packet is too big.
1021 */
1022 if (ssh->pktin.maxlen < st->packetlen + st->maclen) {
1023 ssh->pktin.maxlen = st->packetlen + st->maclen;
1024 ssh->pktin.data = sresize(ssh->pktin.data,
1025 ssh->pktin.maxlen + APIEXTRA,
1026 unsigned char);
1027 }
1028
1029 /*
1030 * Read and decrypt the remainder of the packet.
1031 */
1032 for (st->i = st->cipherblk; st->i < st->packetlen + st->maclen;
1033 st->i++) {
1034 while ((*datalen) == 0)
1035 crReturn(st->packetlen + st->maclen - st->i);
1036 ssh->pktin.data[st->i] = *(*data)++;
1037 (*datalen)--;
1038 }
1039 /* Decrypt everything _except_ the MAC. */
1040 if (ssh->sccipher)
1041 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
1042 ssh->pktin.data + st->cipherblk,
1043 st->packetlen - st->cipherblk);
1044
1045 /*
1046 * Check the MAC.
1047 */
1048 if (ssh->scmac
1049 && !ssh->scmac->verify(ssh->sc_mac_ctx, ssh->pktin.data, st->len + 4,
1050 st->incoming_sequence)) {
1051 bombout(("Incorrect MAC received on packet"));
1052 crStop(0);
1053 }
1054 st->incoming_sequence++; /* whether or not we MACed */
1055
1056 /*
1057 * Decompress packet payload.
1058 */
1059 {
1060 unsigned char *newpayload;
1061 int newlen;
1062 if (ssh->sccomp &&
1063 ssh->sccomp->decompress(ssh->sc_comp_ctx,
1064 ssh->pktin.data + 5, ssh->pktin.length - 5,
1065 &newpayload, &newlen)) {
1066 if (ssh->pktin.maxlen < newlen + 5) {
1067 ssh->pktin.maxlen = newlen + 5;
1068 ssh->pktin.data = sresize(ssh->pktin.data,
1069 ssh->pktin.maxlen + APIEXTRA,
1070 unsigned char);
1071 }
1072 ssh->pktin.length = 5 + newlen;
1073 memcpy(ssh->pktin.data + 5, newpayload, newlen);
1074 sfree(newpayload);
1075 }
1076 }
1077
1078 ssh->pktin.savedpos = 6;
1079 ssh->pktin.body = ssh->pktin.data;
1080 ssh->pktin.type = ssh->pktin.data[5];
1081
1082 if (ssh->logctx)
1083 log_packet(ssh->logctx, PKT_INCOMING, ssh->pktin.type,
1084 ssh2_pkt_type(ssh->pkt_ctx, ssh->pktin.type),
1085 ssh->pktin.data+6, ssh->pktin.length-6);
1086
1087 switch (ssh->pktin.type) {
1088 /*
1089 * These packets we must handle instantly.
1090 */
1091 case SSH2_MSG_DISCONNECT:
1092 {
1093 /* log reason code in disconnect message */
1094 char *buf;
1095 int nowlen;
1096 int reason = GET_32BIT(ssh->pktin.data + 6);
1097 unsigned msglen = GET_32BIT(ssh->pktin.data + 10);
1098
1099 if (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) {
1100 buf = dupprintf("Received disconnect message (%s)",
1101 ssh2_disconnect_reasons[reason]);
1102 } else {
1103 buf = dupprintf("Received disconnect message (unknown"
1104 " type %d)", reason);
1105 }
1106 logevent(buf);
1107 sfree(buf);
1108 buf = dupprintf("Disconnection message text: %n%.*s",
1109 &nowlen, msglen, ssh->pktin.data + 14);
1110 logevent(buf);
1111 bombout(("Server sent disconnect message\ntype %d (%s):\n\"%s\"",
1112 reason,
1113 (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) ?
1114 ssh2_disconnect_reasons[reason] : "unknown",
1115 buf+nowlen));
1116 sfree(buf);
1117 crStop(0);
1118 }
1119 break;
1120 case SSH2_MSG_IGNORE:
1121 goto next_packet;
1122 case SSH2_MSG_DEBUG:
1123 {
1124 /* log the debug message */
1125 char buf[512];
1126 /* int display = ssh->pktin.body[6]; */
1127 int stringlen = GET_32BIT(ssh->pktin.data+7);
1128 int prefix;
1129 strcpy(buf, "Remote debug message: ");
1130 prefix = strlen(buf);
1131 if (stringlen > (int)(sizeof(buf)-prefix-1))
1132 stringlen = sizeof(buf)-prefix-1;
1133 memcpy(buf + prefix, ssh->pktin.data + 11, stringlen);
1134 buf[prefix + stringlen] = '\0';
1135 logevent(buf);
1136 }
1137 goto next_packet; /* FIXME: print the debug message */
1138
1139 /*
1140 * These packets we need do nothing about here.
1141 */
1142 case SSH2_MSG_UNIMPLEMENTED:
1143 case SSH2_MSG_SERVICE_REQUEST:
1144 case SSH2_MSG_SERVICE_ACCEPT:
1145 case SSH2_MSG_KEXINIT:
1146 case SSH2_MSG_NEWKEYS:
1147 case SSH2_MSG_KEXDH_INIT:
1148 case SSH2_MSG_KEXDH_REPLY:
1149 /* case SSH2_MSG_KEX_DH_GEX_REQUEST: duplicate case value */
1150 /* case SSH2_MSG_KEX_DH_GEX_GROUP: duplicate case value */
1151 case SSH2_MSG_KEX_DH_GEX_INIT:
1152 case SSH2_MSG_KEX_DH_GEX_REPLY:
1153 case SSH2_MSG_USERAUTH_REQUEST:
1154 case SSH2_MSG_USERAUTH_FAILURE:
1155 case SSH2_MSG_USERAUTH_SUCCESS:
1156 case SSH2_MSG_USERAUTH_BANNER:
1157 case SSH2_MSG_USERAUTH_PK_OK:
1158 /* case SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ: duplicate case value */
1159 /* case SSH2_MSG_USERAUTH_INFO_REQUEST: duplicate case value */
1160 case SSH2_MSG_USERAUTH_INFO_RESPONSE:
1161 case SSH2_MSG_GLOBAL_REQUEST:
1162 case SSH2_MSG_REQUEST_SUCCESS:
1163 case SSH2_MSG_REQUEST_FAILURE:
1164 case SSH2_MSG_CHANNEL_OPEN:
1165 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION:
1166 case SSH2_MSG_CHANNEL_OPEN_FAILURE:
1167 case SSH2_MSG_CHANNEL_WINDOW_ADJUST:
1168 case SSH2_MSG_CHANNEL_DATA:
1169 case SSH2_MSG_CHANNEL_EXTENDED_DATA:
1170 case SSH2_MSG_CHANNEL_EOF:
1171 case SSH2_MSG_CHANNEL_CLOSE:
1172 case SSH2_MSG_CHANNEL_REQUEST:
1173 case SSH2_MSG_CHANNEL_SUCCESS:
1174 case SSH2_MSG_CHANNEL_FAILURE:
1175 break;
1176
1177 /*
1178 * For anything else we send SSH2_MSG_UNIMPLEMENTED.
1179 */
1180 default:
1181 ssh2_pkt_init(ssh, SSH2_MSG_UNIMPLEMENTED);
1182 ssh2_pkt_adduint32(ssh, st->incoming_sequence - 1);
1183 ssh2_pkt_send(ssh);
1184 break;
1185 }
1186
1187 crFinish(0);
1188 }
1189
1190 static void ssh1_pktout_size(Ssh ssh, int len)
1191 {
1192 int pad, biglen;
1193
1194 len += 5; /* type and CRC */
1195 pad = 8 - (len % 8);
1196 biglen = len + pad;
1197
1198 ssh->pktout.length = len - 5;
1199 if (ssh->pktout.maxlen < biglen) {
1200 ssh->pktout.maxlen = biglen;
1201 #ifdef MSCRYPTOAPI
1202 /* Allocate enough buffer space for extra block
1203 * for MS CryptEncrypt() */
1204 ssh->pktout.data = sresize(ssh->pktout.data, biglen + 12,
1205 unsigned char);
1206 #else
1207 ssh->pktout.data = sresize(ssh->pktout.data, biglen + 4,
1208 unsigned char);
1209 #endif
1210 }
1211 ssh->pktout.body = ssh->pktout.data + 4 + pad + 1;
1212 }
1213
1214 static void s_wrpkt_start(Ssh ssh, int type, int len)
1215 {
1216 ssh1_pktout_size(ssh, len);
1217 ssh->pktout.type = type;
1218 }
1219
1220 static int s_wrpkt_prepare(Ssh ssh)
1221 {
1222 int pad, biglen, i;
1223 unsigned long crc;
1224 #ifdef __SC__
1225 /*
1226 * XXX various versions of SC (including 8.8.4) screw up the
1227 * register allocation in this function and use the same register
1228 * (D6) for len and as a temporary, with predictable results. The
1229 * following sledgehammer prevents this.
1230 */
1231 volatile
1232 #endif
1233 int len;
1234
1235 ssh->pktout.body[-1] = ssh->pktout.type;
1236
1237 if (ssh->logctx)
1238 log_packet(ssh->logctx, PKT_OUTGOING, ssh->pktout.type,
1239 ssh1_pkt_type(ssh->pktout.type),
1240 ssh->pktout.body, ssh->pktout.length);
1241
1242 if (ssh->v1_compressing) {
1243 unsigned char *compblk;
1244 int complen;
1245 zlib_compress_block(ssh->cs_comp_ctx,
1246 ssh->pktout.body - 1, ssh->pktout.length + 1,
1247 &compblk, &complen);
1248 ssh1_pktout_size(ssh, complen - 1);
1249 memcpy(ssh->pktout.body - 1, compblk, complen);
1250 sfree(compblk);
1251 }
1252
1253 len = ssh->pktout.length + 5; /* type and CRC */
1254 pad = 8 - (len % 8);
1255 biglen = len + pad;
1256
1257 for (i = 0; i < pad; i++)
1258 ssh->pktout.data[i + 4] = random_byte();
1259 crc = crc32_compute(ssh->pktout.data + 4, biglen - 4);
1260 PUT_32BIT(ssh->pktout.data + biglen, crc);
1261 PUT_32BIT(ssh->pktout.data, len);
1262
1263 if (ssh->cipher)
1264 ssh->cipher->encrypt(ssh->v1_cipher_ctx, ssh->pktout.data + 4, biglen);
1265
1266 return biglen + 4;
1267 }
1268
1269 static void s_wrpkt(Ssh ssh)
1270 {
1271 int len, backlog;
1272 len = s_wrpkt_prepare(ssh);
1273 backlog = sk_write(ssh->s, (char *)ssh->pktout.data, len);
1274 if (backlog > SSH_MAX_BACKLOG)
1275 ssh_throttle_all(ssh, 1, backlog);
1276 }
1277
1278 static void s_wrpkt_defer(Ssh ssh)
1279 {
1280 int len;
1281 len = s_wrpkt_prepare(ssh);
1282 if (ssh->deferred_len + len > ssh->deferred_size) {
1283 ssh->deferred_size = ssh->deferred_len + len + 128;
1284 ssh->deferred_send_data = sresize(ssh->deferred_send_data,
1285 ssh->deferred_size,
1286 unsigned char);
1287 }
1288 memcpy(ssh->deferred_send_data + ssh->deferred_len, ssh->pktout.data, len);
1289 ssh->deferred_len += len;
1290 }
1291
1292 /*
1293 * Construct a packet with the specified contents.
1294 */
1295 static void construct_packet(Ssh ssh, int pkttype, va_list ap1, va_list ap2)
1296 {
1297 unsigned char *p, *argp, argchar;
1298 unsigned long argint;
1299 int pktlen, argtype, arglen;
1300 Bignum bn;
1301
1302 pktlen = 0;
1303 while ((argtype = va_arg(ap1, int)) != PKT_END) {
1304 switch (argtype) {
1305 case PKT_INT:
1306 (void) va_arg(ap1, int);
1307 pktlen += 4;
1308 break;
1309 case PKT_CHAR:
1310 (void) va_arg(ap1, int);
1311 pktlen++;
1312 break;
1313 case PKT_DATA:
1314 (void) va_arg(ap1, unsigned char *);
1315 arglen = va_arg(ap1, int);
1316 pktlen += arglen;
1317 break;
1318 case PKT_STR:
1319 argp = va_arg(ap1, unsigned char *);
1320 arglen = strlen((char *)argp);
1321 pktlen += 4 + arglen;
1322 break;
1323 case PKT_BIGNUM:
1324 bn = va_arg(ap1, Bignum);
1325 pktlen += ssh1_bignum_length(bn);
1326 break;
1327 default:
1328 assert(0);
1329 }
1330 }
1331
1332 s_wrpkt_start(ssh, pkttype, pktlen);
1333 p = ssh->pktout.body;
1334
1335 while ((argtype = va_arg(ap2, int)) != PKT_END) {
1336 switch (argtype) {
1337 case PKT_INT:
1338 argint = va_arg(ap2, int);
1339 PUT_32BIT(p, argint);
1340 p += 4;
1341 break;
1342 case PKT_CHAR:
1343 argchar = (unsigned char) va_arg(ap2, int);
1344 *p = argchar;
1345 p++;
1346 break;
1347 case PKT_DATA:
1348 argp = va_arg(ap2, unsigned char *);
1349 arglen = va_arg(ap2, int);
1350 memcpy(p, argp, arglen);
1351 p += arglen;
1352 break;
1353 case PKT_STR:
1354 argp = va_arg(ap2, unsigned char *);
1355 arglen = strlen((char *)argp);
1356 PUT_32BIT(p, arglen);
1357 memcpy(p + 4, argp, arglen);
1358 p += 4 + arglen;
1359 break;
1360 case PKT_BIGNUM:
1361 bn = va_arg(ap2, Bignum);
1362 p += ssh1_write_bignum(p, bn);
1363 break;
1364 }
1365 }
1366 }
1367
1368 static void send_packet(Ssh ssh, int pkttype, ...)
1369 {
1370 va_list ap1, ap2;
1371 va_start(ap1, pkttype);
1372 va_start(ap2, pkttype);
1373 construct_packet(ssh, pkttype, ap1, ap2);
1374 s_wrpkt(ssh);
1375 }
1376
1377 static void defer_packet(Ssh ssh, int pkttype, ...)
1378 {
1379 va_list ap1, ap2;
1380 va_start(ap1, pkttype);
1381 va_start(ap2, pkttype);
1382 construct_packet(ssh, pkttype, ap1, ap2);
1383 s_wrpkt_defer(ssh);
1384 }
1385
1386 static int ssh_versioncmp(char *a, char *b)
1387 {
1388 char *ae, *be;
1389 unsigned long av, bv;
1390
1391 av = strtoul(a, &ae, 10);
1392 bv = strtoul(b, &be, 10);
1393 if (av != bv)
1394 return (av < bv ? -1 : +1);
1395 if (*ae == '.')
1396 ae++;
1397 if (*be == '.')
1398 be++;
1399 av = strtoul(ae, &ae, 10);
1400 bv = strtoul(be, &be, 10);
1401 if (av != bv)
1402 return (av < bv ? -1 : +1);
1403 return 0;
1404 }
1405
1406 /*
1407 * Utility routines for putting an SSH-protocol `string' and
1408 * `uint32' into a SHA state.
1409 */
1410 #include <stdio.h>
1411 static void sha_string(SHA_State * s, void *str, int len)
1412 {
1413 unsigned char lenblk[4];
1414 PUT_32BIT(lenblk, len);
1415 SHA_Bytes(s, lenblk, 4);
1416 SHA_Bytes(s, str, len);
1417 }
1418
1419 static void sha_uint32(SHA_State * s, unsigned i)
1420 {
1421 unsigned char intblk[4];
1422 PUT_32BIT(intblk, i);
1423 SHA_Bytes(s, intblk, 4);
1424 }
1425
1426 /*
1427 * SSH2 packet construction functions.
1428 */
1429 static void ssh2_pkt_ensure(Ssh ssh, int length)
1430 {
1431 if (ssh->pktout.maxlen < length) {
1432 ssh->pktout.maxlen = length + 256;
1433 ssh->pktout.data = sresize(ssh->pktout.data,
1434 ssh->pktout.maxlen + APIEXTRA,
1435 unsigned char);
1436 if (!ssh->pktout.data)
1437 fatalbox("Out of memory");
1438 }
1439 }
1440 static void ssh2_pkt_adddata(Ssh ssh, void *data, int len)
1441 {
1442 ssh->pktout.length += len;
1443 ssh2_pkt_ensure(ssh, ssh->pktout.length);
1444 memcpy(ssh->pktout.data + ssh->pktout.length - len, data, len);
1445 }
1446 static void ssh2_pkt_addbyte(Ssh ssh, unsigned char byte)
1447 {
1448 ssh2_pkt_adddata(ssh, &byte, 1);
1449 }
1450 static void ssh2_pkt_init(Ssh ssh, int pkt_type)
1451 {
1452 ssh->pktout.length = 5;
1453 ssh2_pkt_addbyte(ssh, (unsigned char) pkt_type);
1454 }
1455 static void ssh2_pkt_addbool(Ssh ssh, unsigned char value)
1456 {
1457 ssh2_pkt_adddata(ssh, &value, 1);
1458 }
1459 static void ssh2_pkt_adduint32(Ssh ssh, unsigned long value)
1460 {
1461 unsigned char x[4];
1462 PUT_32BIT(x, value);
1463 ssh2_pkt_adddata(ssh, x, 4);
1464 }
1465 static void ssh2_pkt_addstring_start(Ssh ssh)
1466 {
1467 ssh2_pkt_adduint32(ssh, 0);
1468 ssh->pktout.savedpos = ssh->pktout.length;
1469 }
1470 static void ssh2_pkt_addstring_str(Ssh ssh, char *data)
1471 {
1472 ssh2_pkt_adddata(ssh, data, strlen(data));
1473 PUT_32BIT(ssh->pktout.data + ssh->pktout.savedpos - 4,
1474 ssh->pktout.length - ssh->pktout.savedpos);
1475 }
1476 static void ssh2_pkt_addstring_data(Ssh ssh, char *data, int len)
1477 {
1478 ssh2_pkt_adddata(ssh, data, len);
1479 PUT_32BIT(ssh->pktout.data + ssh->pktout.savedpos - 4,
1480 ssh->pktout.length - ssh->pktout.savedpos);
1481 }
1482 static void ssh2_pkt_addstring(Ssh ssh, char *data)
1483 {
1484 ssh2_pkt_addstring_start(ssh);
1485 ssh2_pkt_addstring_str(ssh, data);
1486 }
1487 static unsigned char *ssh2_mpint_fmt(Bignum b, int *len)
1488 {
1489 unsigned char *p;
1490 int i, n = (bignum_bitcount(b) + 7) / 8;
1491 p = snewn(n + 1, unsigned char);
1492 if (!p)
1493 fatalbox("out of memory");
1494 p[0] = 0;
1495 for (i = 1; i <= n; i++)
1496 p[i] = bignum_byte(b, n - i);
1497 i = 0;
1498 while (i <= n && p[i] == 0 && (p[i + 1] & 0x80) == 0)
1499 i++;
1500 memmove(p, p + i, n + 1 - i);
1501 *len = n + 1 - i;
1502 return p;
1503 }
1504 static void ssh2_pkt_addmp(Ssh ssh, Bignum b)
1505 {
1506 unsigned char *p;
1507 int len;
1508 p = ssh2_mpint_fmt(b, &len);
1509 ssh2_pkt_addstring_start(ssh);
1510 ssh2_pkt_addstring_data(ssh, (char *)p, len);
1511 sfree(p);
1512 }
1513
1514 /*
1515 * Construct an SSH2 final-form packet: compress it, encrypt it,
1516 * put the MAC on it. Final packet, ready to be sent, is stored in
1517 * ssh->pktout.data. Total length is returned.
1518 */
1519 static int ssh2_pkt_construct(Ssh ssh)
1520 {
1521 int cipherblk, maclen, padding, i;
1522
1523 if (ssh->logctx)
1524 log_packet(ssh->logctx, PKT_OUTGOING, ssh->pktout.data[5],
1525 ssh2_pkt_type(ssh->pkt_ctx, ssh->pktout.data[5]),
1526 ssh->pktout.data + 6, ssh->pktout.length - 6);
1527
1528 /*
1529 * Compress packet payload.
1530 */
1531 {
1532 unsigned char *newpayload;
1533 int newlen;
1534 if (ssh->cscomp &&
1535 ssh->cscomp->compress(ssh->cs_comp_ctx, ssh->pktout.data + 5,
1536 ssh->pktout.length - 5,
1537 &newpayload, &newlen)) {
1538 ssh->pktout.length = 5;
1539 ssh2_pkt_adddata(ssh, newpayload, newlen);
1540 sfree(newpayload);
1541 }
1542 }
1543
1544 /*
1545 * Add padding. At least four bytes, and must also bring total
1546 * length (minus MAC) up to a multiple of the block size.
1547 */
1548 cipherblk = ssh->cscipher ? ssh->cscipher->blksize : 8; /* block size */
1549 cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */
1550 padding = 4;
1551 padding +=
1552 (cipherblk - (ssh->pktout.length + padding) % cipherblk) % cipherblk;
1553 maclen = ssh->csmac ? ssh->csmac->len : 0;
1554 ssh2_pkt_ensure(ssh, ssh->pktout.length + padding + maclen);
1555 ssh->pktout.data[4] = padding;
1556 for (i = 0; i < padding; i++)
1557 ssh->pktout.data[ssh->pktout.length + i] = random_byte();
1558 PUT_32BIT(ssh->pktout.data, ssh->pktout.length + padding - 4);
1559 if (ssh->csmac)
1560 ssh->csmac->generate(ssh->cs_mac_ctx, ssh->pktout.data,
1561 ssh->pktout.length + padding,
1562 ssh->v2_outgoing_sequence);
1563 ssh->v2_outgoing_sequence++; /* whether or not we MACed */
1564
1565 if (ssh->cscipher)
1566 ssh->cscipher->encrypt(ssh->cs_cipher_ctx,
1567 ssh->pktout.data, ssh->pktout.length + padding);
1568
1569 /* Ready-to-send packet starts at ssh->pktout.data. We return length. */
1570 return ssh->pktout.length + padding + maclen;
1571 }
1572
1573 /*
1574 * Construct and send an SSH2 packet immediately.
1575 */
1576 static void ssh2_pkt_send(Ssh ssh)
1577 {
1578 int len;
1579 int backlog;
1580 len = ssh2_pkt_construct(ssh);
1581 backlog = sk_write(ssh->s, (char *)ssh->pktout.data, len);
1582 if (backlog > SSH_MAX_BACKLOG)
1583 ssh_throttle_all(ssh, 1, backlog);
1584 }
1585
1586 /*
1587 * Construct an SSH2 packet and add it to a deferred data block.
1588 * Useful for sending multiple packets in a single sk_write() call,
1589 * to prevent a traffic-analysing listener from being able to work
1590 * out the length of any particular packet (such as the password
1591 * packet).
1592 *
1593 * Note that because SSH2 sequence-numbers its packets, this can
1594 * NOT be used as an m4-style `defer' allowing packets to be
1595 * constructed in one order and sent in another.
1596 */
1597 static void ssh2_pkt_defer(Ssh ssh)
1598 {
1599 int len = ssh2_pkt_construct(ssh);
1600 if (ssh->deferred_len + len > ssh->deferred_size) {
1601 ssh->deferred_size = ssh->deferred_len + len + 128;
1602 ssh->deferred_send_data = sresize(ssh->deferred_send_data,
1603 ssh->deferred_size,
1604 unsigned char);
1605 }
1606 memcpy(ssh->deferred_send_data + ssh->deferred_len, ssh->pktout.data, len);
1607 ssh->deferred_len += len;
1608 }
1609
1610 /*
1611 * Send the whole deferred data block constructed by
1612 * ssh2_pkt_defer() or SSH1's defer_packet().
1613 */
1614 static void ssh_pkt_defersend(Ssh ssh)
1615 {
1616 int backlog;
1617 backlog = sk_write(ssh->s, (char *)ssh->deferred_send_data,
1618 ssh->deferred_len);
1619 ssh->deferred_len = ssh->deferred_size = 0;
1620 sfree(ssh->deferred_send_data);
1621 ssh->deferred_send_data = NULL;
1622 if (backlog > SSH_MAX_BACKLOG)
1623 ssh_throttle_all(ssh, 1, backlog);
1624 }
1625
1626 #if 0
1627 void bndebug(char *string, Bignum b)
1628 {
1629 unsigned char *p;
1630 int i, len;
1631 p = ssh2_mpint_fmt(b, &len);
1632 debug(("%s", string));
1633 for (i = 0; i < len; i++)
1634 debug((" %02x", p[i]));
1635 debug(("\n"));
1636 sfree(p);
1637 }
1638 #endif
1639
1640 static void sha_mpint(SHA_State * s, Bignum b)
1641 {
1642 unsigned char *p;
1643 int len;
1644 p = ssh2_mpint_fmt(b, &len);
1645 sha_string(s, p, len);
1646 sfree(p);
1647 }
1648
1649 /*
1650 * Packet decode functions for both SSH1 and SSH2.
1651 */
1652 static unsigned long ssh_pkt_getuint32(Ssh ssh)
1653 {
1654 unsigned long value;
1655 if (ssh->pktin.length - ssh->pktin.savedpos < 4)
1656 return 0; /* arrgh, no way to decline (FIXME?) */
1657 value = GET_32BIT(ssh->pktin.body + ssh->pktin.savedpos);
1658 ssh->pktin.savedpos += 4;
1659 return value;
1660 }
1661 static int ssh2_pkt_getbool(Ssh ssh)
1662 {
1663 unsigned long value;
1664 if (ssh->pktin.length - ssh->pktin.savedpos < 1)
1665 return 0; /* arrgh, no way to decline (FIXME?) */
1666 value = ssh->pktin.body[ssh->pktin.savedpos] != 0;
1667 ssh->pktin.savedpos++;
1668 return value;
1669 }
1670 static void ssh_pkt_getstring(Ssh ssh, char **p, int *length)
1671 {
1672 int len;
1673 *p = NULL;
1674 *length = 0;
1675 if (ssh->pktin.length - ssh->pktin.savedpos < 4)
1676 return;
1677 len = GET_32BIT(ssh->pktin.body + ssh->pktin.savedpos);
1678 if (len < 0)
1679 return;
1680 *length = len;
1681 ssh->pktin.savedpos += 4;
1682 if (ssh->pktin.length - ssh->pktin.savedpos < *length)
1683 return;
1684 *p = (char *)(ssh->pktin.body + ssh->pktin.savedpos);
1685 ssh->pktin.savedpos += *length;
1686 }
1687 static void *ssh_pkt_getdata(Ssh ssh, int length)
1688 {
1689 if (ssh->pktin.length - ssh->pktin.savedpos < length)
1690 return NULL;
1691 ssh->pktin.savedpos += length;
1692 return ssh->pktin.body + (ssh->pktin.savedpos - length);
1693 }
1694 static int ssh1_pkt_getrsakey(Ssh ssh, struct RSAKey *key,
1695 unsigned char **keystr)
1696 {
1697 int j;
1698
1699 j = makekey(ssh->pktin.body + ssh->pktin.savedpos,
1700 ssh->pktin.length - ssh->pktin.savedpos,
1701 key, keystr, 0);
1702
1703 if (j < 0)
1704 return FALSE;
1705
1706 ssh->pktin.savedpos += j;
1707 assert(ssh->pktin.savedpos < ssh->pktin.length);
1708
1709 return TRUE;
1710 }
1711 static Bignum ssh1_pkt_getmp(Ssh ssh)
1712 {
1713 int j;
1714 Bignum b;
1715
1716 j = ssh1_read_bignum(ssh->pktin.body + ssh->pktin.savedpos,
1717 ssh->pktin.length - ssh->pktin.savedpos, &b);
1718
1719 if (j < 0)
1720 return NULL;
1721
1722 ssh->pktin.savedpos += j;
1723 return b;
1724 }
1725 static Bignum ssh2_pkt_getmp(Ssh ssh)
1726 {
1727 char *p;
1728 int length;
1729 Bignum b;
1730
1731 ssh_pkt_getstring(ssh, &p, &length);
1732 if (!p)
1733 return NULL;
1734 if (p[0] & 0x80) {
1735 bombout(("internal error: Can't handle negative mpints"));
1736 return NULL;
1737 }
1738 b = bignum_from_bytes((unsigned char *)p, length);
1739 return b;
1740 }
1741
1742 /*
1743 * Helper function to add an SSH2 signature blob to a packet.
1744 * Expects to be shown the public key blob as well as the signature
1745 * blob. Normally works just like ssh2_pkt_addstring, but will
1746 * fiddle with the signature packet if necessary for
1747 * BUG_SSH2_RSA_PADDING.
1748 */
1749 static void ssh2_add_sigblob(Ssh ssh, void *pkblob_v, int pkblob_len,
1750 void *sigblob_v, int sigblob_len)
1751 {
1752 unsigned char *pkblob = (unsigned char *)pkblob_v;
1753 unsigned char *sigblob = (unsigned char *)sigblob_v;
1754
1755 /* dmemdump(pkblob, pkblob_len); */
1756 /* dmemdump(sigblob, sigblob_len); */
1757
1758 /*
1759 * See if this is in fact an ssh-rsa signature and a buggy
1760 * server; otherwise we can just do this the easy way.
1761 */
1762 if ((ssh->remote_bugs & BUG_SSH2_RSA_PADDING) &&
1763 (GET_32BIT(pkblob) == 7 && !memcmp(pkblob+4, "ssh-rsa", 7))) {
1764 int pos, len, siglen;
1765
1766 /*
1767 * Find the byte length of the modulus.
1768 */
1769
1770 pos = 4+7; /* skip over "ssh-rsa" */
1771 pos += 4 + GET_32BIT(pkblob+pos); /* skip over exponent */
1772 len = GET_32BIT(pkblob+pos); /* find length of modulus */
1773 pos += 4; /* find modulus itself */
1774 while (len > 0 && pkblob[pos] == 0)
1775 len--, pos++;
1776 /* debug(("modulus length is %d\n", len)); */
1777
1778 /*
1779 * Now find the signature integer.
1780 */
1781 pos = 4+7; /* skip over "ssh-rsa" */
1782 siglen = GET_32BIT(sigblob+pos);
1783 /* debug(("signature length is %d\n", siglen)); */
1784
1785 if (len != siglen) {
1786 unsigned char newlen[4];
1787 ssh2_pkt_addstring_start(ssh);
1788 ssh2_pkt_addstring_data(ssh, (char *)sigblob, pos);
1789 /* dmemdump(sigblob, pos); */
1790 pos += 4; /* point to start of actual sig */
1791 PUT_32BIT(newlen, len);
1792 ssh2_pkt_addstring_data(ssh, (char *)newlen, 4);
1793 /* dmemdump(newlen, 4); */
1794 newlen[0] = 0;
1795 while (len-- > siglen) {
1796 ssh2_pkt_addstring_data(ssh, (char *)newlen, 1);
1797 /* dmemdump(newlen, 1); */
1798 }
1799 ssh2_pkt_addstring_data(ssh, (char *)(sigblob+pos), siglen);
1800 /* dmemdump(sigblob+pos, siglen); */
1801 return;
1802 }
1803
1804 /* Otherwise fall through and do it the easy way. */
1805 }
1806
1807 ssh2_pkt_addstring_start(ssh);
1808 ssh2_pkt_addstring_data(ssh, (char *)sigblob, sigblob_len);
1809 }
1810
1811 /*
1812 * Examine the remote side's version string and compare it against
1813 * a list of known buggy implementations.
1814 */
1815 static void ssh_detect_bugs(Ssh ssh, char *vstring)
1816 {
1817 char *imp; /* pointer to implementation part */
1818 imp = vstring;
1819 imp += strcspn(imp, "-");
1820 if (*imp) imp++;
1821 imp += strcspn(imp, "-");
1822 if (*imp) imp++;
1823
1824 ssh->remote_bugs = 0;
1825
1826 if (ssh->cfg.sshbug_ignore1 == FORCE_ON ||
1827 (ssh->cfg.sshbug_ignore1 == AUTO &&
1828 (!strcmp(imp, "1.2.18") || !strcmp(imp, "1.2.19") ||
1829 !strcmp(imp, "1.2.20") || !strcmp(imp, "1.2.21") ||
1830 !strcmp(imp, "1.2.22") || !strcmp(imp, "Cisco-1.25") ||
1831 !strcmp(imp, "OSU_1.4alpha3") || !strcmp(imp, "OSU_1.5alpha4")))) {
1832 /*
1833 * These versions don't support SSH1_MSG_IGNORE, so we have
1834 * to use a different defence against password length
1835 * sniffing.
1836 */
1837 ssh->remote_bugs |= BUG_CHOKES_ON_SSH1_IGNORE;
1838 logevent("We believe remote version has SSH1 ignore bug");
1839 }
1840
1841 if (ssh->cfg.sshbug_plainpw1 == FORCE_ON ||
1842 (ssh->cfg.sshbug_plainpw1 == AUTO &&
1843 (!strcmp(imp, "Cisco-1.25") || !strcmp(imp, "OSU_1.4alpha3")))) {
1844 /*
1845 * These versions need a plain password sent; they can't
1846 * handle having a null and a random length of data after
1847 * the password.
1848 */
1849 ssh->remote_bugs |= BUG_NEEDS_SSH1_PLAIN_PASSWORD;
1850 logevent("We believe remote version needs a plain SSH1 password");
1851 }
1852
1853 if (ssh->cfg.sshbug_rsa1 == FORCE_ON ||
1854 (ssh->cfg.sshbug_rsa1 == AUTO &&
1855 (!strcmp(imp, "Cisco-1.25")))) {
1856 /*
1857 * These versions apparently have no clue whatever about
1858 * RSA authentication and will panic and die if they see
1859 * an AUTH_RSA message.
1860 */
1861 ssh->remote_bugs |= BUG_CHOKES_ON_RSA;
1862 logevent("We believe remote version can't handle RSA authentication");
1863 }
1864
1865 if (ssh->cfg.sshbug_hmac2 == FORCE_ON ||
1866 (ssh->cfg.sshbug_hmac2 == AUTO &&
1867 !wc_match("* VShell", imp) &&
1868 (wc_match("2.1.0*", imp) || wc_match("2.0.*", imp) ||
1869 wc_match("2.2.0*", imp) || wc_match("2.3.0*", imp) ||
1870 wc_match("2.1 *", imp)))) {
1871 /*
1872 * These versions have the HMAC bug.
1873 */
1874 ssh->remote_bugs |= BUG_SSH2_HMAC;
1875 logevent("We believe remote version has SSH2 HMAC bug");
1876 }
1877
1878 if (ssh->cfg.sshbug_derivekey2 == FORCE_ON ||
1879 (ssh->cfg.sshbug_derivekey2 == AUTO &&
1880 !wc_match("* VShell", imp) &&
1881 (wc_match("2.0.0*", imp) || wc_match("2.0.10*", imp) ))) {
1882 /*
1883 * These versions have the key-derivation bug (failing to
1884 * include the literal shared secret in the hashes that
1885 * generate the keys).
1886 */
1887 ssh->remote_bugs |= BUG_SSH2_DERIVEKEY;
1888 logevent("We believe remote version has SSH2 key-derivation bug");
1889 }
1890
1891 if (ssh->cfg.sshbug_rsapad2 == FORCE_ON ||
1892 (ssh->cfg.sshbug_rsapad2 == AUTO &&
1893 (wc_match("OpenSSH_2.[5-9]*", imp) ||
1894 wc_match("OpenSSH_3.[0-2]*", imp)))) {
1895 /*
1896 * These versions have the SSH2 RSA padding bug.
1897 */
1898 ssh->remote_bugs |= BUG_SSH2_RSA_PADDING;
1899 logevent("We believe remote version has SSH2 RSA padding bug");
1900 }
1901
1902 if (ssh->cfg.sshbug_pksessid2 == FORCE_ON ||
1903 (ssh->cfg.sshbug_pksessid2 == AUTO &&
1904 wc_match("OpenSSH_2.[0-2]*", imp))) {
1905 /*
1906 * These versions have the SSH2 session-ID bug in
1907 * public-key authentication.
1908 */
1909 ssh->remote_bugs |= BUG_SSH2_PK_SESSIONID;
1910 logevent("We believe remote version has SSH2 public-key-session-ID bug");
1911 }
1912
1913 if (ssh->cfg.sshbug_dhgex2 == FORCE_ON) {
1914 /*
1915 * User specified the SSH2 DH GEX bug.
1916 */
1917 ssh->remote_bugs |= BUG_SSH2_DH_GEX;
1918 logevent("We believe remote version has SSH2 DH group exchange bug");
1919 }
1920 }
1921
1922 static int do_ssh_init(Ssh ssh, unsigned char c)
1923 {
1924 struct do_ssh_init_state {
1925 int vslen;
1926 char version[10];
1927 char *vstring;
1928 int vstrsize;
1929 int i;
1930 int proto1, proto2;
1931 };
1932 crState(do_ssh_init_state);
1933
1934 crBegin(ssh->do_ssh_init_crstate);
1935
1936 /* Search for the string "SSH-" in the input. */
1937 s->i = 0;
1938 while (1) {
1939 static const int transS[] = { 1, 2, 2, 1 };
1940 static const int transH[] = { 0, 0, 3, 0 };
1941 static const int transminus[] = { 0, 0, 0, -1 };
1942 if (c == 'S')
1943 s->i = transS[s->i];
1944 else if (c == 'H')
1945 s->i = transH[s->i];
1946 else if (c == '-')
1947 s->i = transminus[s->i];
1948 else
1949 s->i = 0;
1950 if (s->i < 0)
1951 break;
1952 crReturn(1); /* get another character */
1953 }
1954
1955 s->vstrsize = 16;
1956 s->vstring = snewn(s->vstrsize, char);
1957 strcpy(s->vstring, "SSH-");
1958 s->vslen = 4;
1959 s->i = 0;
1960 while (1) {
1961 crReturn(1); /* get another char */
1962 if (s->vslen >= s->vstrsize - 1) {
1963 s->vstrsize += 16;
1964 s->vstring = sresize(s->vstring, s->vstrsize, char);
1965 }
1966 s->vstring[s->vslen++] = c;
1967 if (s->i >= 0) {
1968 if (c == '-') {
1969 s->version[s->i] = '\0';
1970 s->i = -1;
1971 } else if (s->i < sizeof(s->version) - 1)
1972 s->version[s->i++] = c;
1973 } else if (c == '\012')
1974 break;
1975 }
1976
1977 ssh->agentfwd_enabled = FALSE;
1978 ssh->rdpkt2_state.incoming_sequence = 0;
1979
1980 s->vstring[s->vslen] = 0;
1981 s->vstring[strcspn(s->vstring, "\r\n")] = '\0';/* remove EOL chars */
1982 {
1983 char *vlog;
1984 vlog = snewn(20 + s->vslen, char);
1985 sprintf(vlog, "Server version: %s", s->vstring);
1986 logevent(vlog);
1987 sfree(vlog);
1988 }
1989 ssh_detect_bugs(ssh, s->vstring);
1990
1991 /*
1992 * Decide which SSH protocol version to support.
1993 */
1994
1995 /* Anything strictly below "2.0" means protocol 1 is supported. */
1996 s->proto1 = ssh_versioncmp(s->version, "2.0") < 0;
1997 /* Anything greater or equal to "1.99" means protocol 2 is supported. */
1998 s->proto2 = ssh_versioncmp(s->version, "1.99") >= 0;
1999
2000 if (ssh->cfg.sshprot == 0 && !s->proto1) {
2001 bombout(("SSH protocol version 1 required by user but not provided by server"));
2002 crStop(0);
2003 }
2004 if (ssh->cfg.sshprot == 3 && !s->proto2) {
2005 bombout(("SSH protocol version 2 required by user but not provided by server"));
2006 crStop(0);
2007 }
2008
2009 if (s->proto2 && (ssh->cfg.sshprot >= 2 || !s->proto1)) {
2010 /*
2011 * Use v2 protocol.
2012 */
2013 char verstring[80], vlog[100];
2014 sprintf(verstring, "SSH-2.0-%s", sshver);
2015 SHA_Init(&ssh->exhashbase);
2016 /*
2017 * Hash our version string and their version string.
2018 */
2019 sha_string(&ssh->exhashbase, verstring, strlen(verstring));
2020 sha_string(&ssh->exhashbase, s->vstring, strcspn(s->vstring, "\r\n"));
2021 sprintf(vlog, "We claim version: %s", verstring);
2022 logevent(vlog);
2023 strcat(verstring, "\012");
2024 logevent("Using SSH protocol version 2");
2025 sk_write(ssh->s, verstring, strlen(verstring));
2026 ssh->protocol = ssh2_protocol;
2027 ssh->version = 2;
2028 ssh->s_rdpkt = ssh2_rdpkt;
2029 } else {
2030 /*
2031 * Use v1 protocol.
2032 */
2033 char verstring[80], vlog[100];
2034 sprintf(verstring, "SSH-%s-%s",
2035 (ssh_versioncmp(s->version, "1.5") <= 0 ? s->version : "1.5"),
2036 sshver);
2037 sprintf(vlog, "We claim version: %s", verstring);
2038 logevent(vlog);
2039 strcat(verstring, "\012");
2040
2041 logevent("Using SSH protocol version 1");
2042 sk_write(ssh->s, verstring, strlen(verstring));
2043 ssh->protocol = ssh1_protocol;
2044 ssh->version = 1;
2045 ssh->s_rdpkt = ssh1_rdpkt;
2046 }
2047 update_specials_menu(ssh->frontend);
2048 ssh->state = SSH_STATE_BEFORE_SIZE;
2049
2050 sfree(s->vstring);
2051
2052 crFinish(0);
2053 }
2054
2055 static void ssh_gotdata(Ssh ssh, unsigned char *data, int datalen)
2056 {
2057 crBegin(ssh->ssh_gotdata_crstate);
2058
2059 /*
2060 * To begin with, feed the characters one by one to the
2061 * protocol initialisation / selection function do_ssh_init().
2062 * When that returns 0, we're done with the initial greeting
2063 * exchange and can move on to packet discipline.
2064 */
2065 while (1) {
2066 int ret; /* need not be kept across crReturn */
2067 if (datalen == 0)
2068 crReturnV; /* more data please */
2069 ret = do_ssh_init(ssh, *data);
2070 data++;
2071 datalen--;
2072 if (ret == 0)
2073 break;
2074 }
2075
2076 /*
2077 * We emerge from that loop when the initial negotiation is
2078 * over and we have selected an s_rdpkt function. Now pass
2079 * everything to s_rdpkt, and then pass the resulting packets
2080 * to the proper protocol handler.
2081 */
2082 if (datalen == 0)
2083 crReturnV;
2084 while (1) {
2085 while (datalen > 0) {
2086 if (ssh->s_rdpkt(ssh, &data, &datalen) == 0) {
2087 if (ssh->state == SSH_STATE_CLOSED) {
2088 return;
2089 }
2090 ssh->protocol(ssh, NULL, 0, 1);
2091 if (ssh->state == SSH_STATE_CLOSED) {
2092 return;
2093 }
2094 }
2095 }
2096 crReturnV;
2097 }
2098 crFinishV;
2099 }
2100
2101 static void ssh_do_close(Ssh ssh)
2102 {
2103 int i;
2104 struct ssh_channel *c;
2105
2106 ssh->state = SSH_STATE_CLOSED;
2107 if (ssh->s) {
2108 sk_close(ssh->s);
2109 ssh->s = NULL;
2110 }
2111 /*
2112 * Now we must shut down any port and X forwardings going
2113 * through this connection.
2114 */
2115 if (ssh->channels) {
2116 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
2117 switch (c->type) {
2118 case CHAN_X11:
2119 x11_close(c->u.x11.s);
2120 break;
2121 case CHAN_SOCKDATA:
2122 pfd_close(c->u.pfd.s);
2123 break;
2124 }
2125 del234(ssh->channels, c);
2126 if (ssh->version == 2)
2127 bufchain_clear(&c->v.v2.outbuffer);
2128 sfree(c);
2129 }
2130 }
2131 }
2132
2133 static int ssh_closing(Plug plug, const char *error_msg, int error_code,
2134 int calling_back)
2135 {
2136 Ssh ssh = (Ssh) plug;
2137 ssh_do_close(ssh);
2138 if (error_msg) {
2139 /* A socket error has occurred. */
2140 logevent(error_msg);
2141 connection_fatal(ssh->frontend, "%s", error_msg);
2142 } else {
2143 /* Otherwise, the remote side closed the connection normally. */
2144 }
2145 return 0;
2146 }
2147
2148 static int ssh_receive(Plug plug, int urgent, char *data, int len)
2149 {
2150 Ssh ssh = (Ssh) plug;
2151 ssh_gotdata(ssh, (unsigned char *)data, len);
2152 if (ssh->state == SSH_STATE_CLOSED) {
2153 ssh_do_close(ssh);
2154 return 0;
2155 }
2156 return 1;
2157 }
2158
2159 static void ssh_sent(Plug plug, int bufsize)
2160 {
2161 Ssh ssh = (Ssh) plug;
2162 /*
2163 * If the send backlog on the SSH socket itself clears, we
2164 * should unthrottle the whole world if it was throttled.
2165 */
2166 if (bufsize < SSH_MAX_BACKLOG)
2167 ssh_throttle_all(ssh, 0, bufsize);
2168 }
2169
2170 /*
2171 * Connect to specified host and port.
2172 * Returns an error message, or NULL on success.
2173 * Also places the canonical host name into `realhost'. It must be
2174 * freed by the caller.
2175 */
2176 static const char *connect_to_host(Ssh ssh, char *host, int port,
2177 char **realhost, int nodelay, int keepalive)
2178 {
2179 static const struct plug_function_table fn_table = {
2180 ssh_closing,
2181 ssh_receive,
2182 ssh_sent,
2183 NULL
2184 };
2185
2186 SockAddr addr;
2187 const char *err;
2188
2189 ssh->savedhost = snewn(1 + strlen(host), char);
2190 if (!ssh->savedhost)
2191 fatalbox("Out of memory");
2192 strcpy(ssh->savedhost, host);
2193
2194 if (port < 0)
2195 port = 22; /* default ssh port */
2196 ssh->savedport = port;
2197
2198 /*
2199 * Try to find host.
2200 */
2201 logeventf(ssh, "Looking up host \"%s\"", host);
2202 addr = name_lookup(host, port, realhost, &ssh->cfg);
2203 if ((err = sk_addr_error(addr)) != NULL) {
2204 sk_addr_free(addr);
2205 return err;
2206 }
2207
2208 /*
2209 * Open socket.
2210 */
2211 {
2212 char addrbuf[100];
2213 sk_getaddr(addr, addrbuf, 100);
2214 logeventf(ssh, "Connecting to %s port %d", addrbuf, port);
2215 }
2216 ssh->fn = &fn_table;
2217 ssh->s = new_connection(addr, *realhost, port,
2218 0, 1, nodelay, keepalive, (Plug) ssh, &ssh->cfg);
2219 if ((err = sk_socket_error(ssh->s)) != NULL) {
2220 ssh->s = NULL;
2221 return err;
2222 }
2223
2224 return NULL;
2225 }
2226
2227 /*
2228 * Throttle or unthrottle the SSH connection.
2229 */
2230 static void ssh1_throttle(Ssh ssh, int adjust)
2231 {
2232 int old_count = ssh->v1_throttle_count;
2233 ssh->v1_throttle_count += adjust;
2234 assert(ssh->v1_throttle_count >= 0);
2235 if (ssh->v1_throttle_count && !old_count) {
2236 sk_set_frozen(ssh->s, 1);
2237 } else if (!ssh->v1_throttle_count && old_count) {
2238 sk_set_frozen(ssh->s, 0);
2239 }
2240 }
2241
2242 /*
2243 * Throttle or unthrottle _all_ local data streams (for when sends
2244 * on the SSH connection itself back up).
2245 */
2246 static void ssh_throttle_all(Ssh ssh, int enable, int bufsize)
2247 {
2248 int i;
2249 struct ssh_channel *c;
2250
2251 if (enable == ssh->throttled_all)
2252 return;
2253 ssh->throttled_all = enable;
2254 ssh->overall_bufsize = bufsize;
2255 if (!ssh->channels)
2256 return;
2257 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
2258 switch (c->type) {
2259 case CHAN_MAINSESSION:
2260 /*
2261 * This is treated separately, outside the switch.
2262 */
2263 break;
2264 case CHAN_X11:
2265 x11_override_throttle(c->u.x11.s, enable);
2266 break;
2267 case CHAN_AGENT:
2268 /* Agent channels require no buffer management. */
2269 break;
2270 case CHAN_SOCKDATA:
2271 pfd_override_throttle(c->u.pfd.s, enable);
2272 break;
2273 }
2274 }
2275 }
2276
2277 /*
2278 * Username and password input, abstracted off into routines
2279 * reusable in several places - even between SSH1 and SSH2.
2280 */
2281
2282 /* Set up a username or password input loop on a given buffer. */
2283 static void setup_userpass_input(Ssh ssh, char *buffer, int buflen, int echo)
2284 {
2285 ssh->userpass_input_buffer = buffer;
2286 ssh->userpass_input_buflen = buflen;
2287 ssh->userpass_input_bufpos = 0;
2288 ssh->userpass_input_echo = echo;
2289 }
2290
2291 /*
2292 * Process some terminal data in the course of username/password
2293 * input. Returns >0 for success (line of input returned in
2294 * buffer), <0 for failure (user hit ^C/^D, bomb out and exit), 0
2295 * for inconclusive (keep waiting for more input please).
2296 */
2297 static int process_userpass_input(Ssh ssh, unsigned char *in, int inlen)
2298 {
2299 char c;
2300
2301 while (inlen--) {
2302 switch (c = *in++) {
2303 case 10:
2304 case 13:
2305 ssh->userpass_input_buffer[ssh->userpass_input_bufpos] = 0;
2306 ssh->userpass_input_buffer[ssh->userpass_input_buflen-1] = 0;
2307 return +1;
2308 break;
2309 case 8:
2310 case 127:
2311 if (ssh->userpass_input_bufpos > 0) {
2312 if (ssh->userpass_input_echo)
2313 c_write_str(ssh, "\b \b");
2314 ssh->userpass_input_bufpos--;
2315 }
2316 break;
2317 case 21:
2318 case 27:
2319 while (ssh->userpass_input_bufpos > 0) {
2320 if (ssh->userpass_input_echo)
2321 c_write_str(ssh, "\b \b");
2322 ssh->userpass_input_bufpos--;
2323 }
2324 break;
2325 case 3:
2326 case 4:
2327 return -1;
2328 break;
2329 default:
2330 /*
2331 * This simplistic check for printability is disabled
2332 * when we're doing password input, because some people
2333 * have control characters in their passwords.o
2334 */
2335 if ((!ssh->userpass_input_echo ||
2336 (c >= ' ' && c <= '~') ||
2337 ((unsigned char) c >= 160))
2338 && ssh->userpass_input_bufpos < ssh->userpass_input_buflen-1) {
2339 ssh->userpass_input_buffer[ssh->userpass_input_bufpos++] = c;
2340 if (ssh->userpass_input_echo)
2341 c_write(ssh, &c, 1);
2342 }
2343 break;
2344 }
2345 }
2346 return 0;
2347 }
2348
2349 static void ssh_agent_callback(void *sshv, void *reply, int replylen)
2350 {
2351 Ssh ssh = (Ssh) sshv;
2352
2353 ssh->agent_response = reply;
2354 ssh->agent_response_len = replylen;
2355
2356 if (ssh->version == 1)
2357 do_ssh1_login(ssh, NULL, -1, 0);
2358 else
2359 do_ssh2_authconn(ssh, NULL, -1, 0);
2360 }
2361
2362 static void ssh_agentf_callback(void *cv, void *reply, int replylen)
2363 {
2364 struct ssh_channel *c = (struct ssh_channel *)cv;
2365 Ssh ssh = c->ssh;
2366 void *sentreply = reply;
2367
2368 if (!sentreply) {
2369 /* Fake SSH_AGENT_FAILURE. */
2370 sentreply = "\0\0\0\1\5";
2371 replylen = 5;
2372 }
2373 if (ssh->version == 2) {
2374 ssh2_add_channel_data(c, sentreply, replylen);
2375 ssh2_try_send(c);
2376 } else {
2377 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
2378 PKT_INT, c->remoteid,
2379 PKT_INT, replylen,
2380 PKT_DATA, sentreply, replylen,
2381 PKT_END);
2382 }
2383 if (reply)
2384 sfree(reply);
2385 }
2386
2387 /*
2388 * Handle the key exchange and user authentication phases.
2389 */
2390 static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
2391 {
2392 int i, j, ret;
2393 unsigned char cookie[8], *ptr;
2394 struct RSAKey servkey, hostkey;
2395 struct MD5Context md5c;
2396 struct do_ssh1_login_state {
2397 int len;
2398 unsigned char *rsabuf, *keystr1, *keystr2;
2399 unsigned long supported_ciphers_mask, supported_auths_mask;
2400 int tried_publickey, tried_agent;
2401 int tis_auth_refused, ccard_auth_refused;
2402 unsigned char session_id[16];
2403 int cipher_type;
2404 char username[100];
2405 void *publickey_blob;
2406 int publickey_bloblen;
2407 char password[100];
2408 char prompt[200];
2409 int pos;
2410 char c;
2411 int pwpkt_type;
2412 unsigned char request[5], *response, *p;
2413 int responselen;
2414 int keyi, nkeys;
2415 int authed;
2416 struct RSAKey key;
2417 Bignum challenge;
2418 char *commentp;
2419 int commentlen;
2420 };
2421 crState(do_ssh1_login_state);
2422
2423 crBegin(ssh->do_ssh1_login_crstate);
2424
2425 if (!ispkt)
2426 crWaitUntil(ispkt);
2427
2428 if (ssh->pktin.type != SSH1_SMSG_PUBLIC_KEY) {
2429 bombout(("Public key packet not received"));
2430 crStop(0);
2431 }
2432
2433 logevent("Received public keys");
2434
2435 ptr = ssh_pkt_getdata(ssh, 8);
2436 if (!ptr) {
2437 bombout(("SSH1 public key packet stopped before random cookie"));
2438 crStop(0);
2439 }
2440 memcpy(cookie, ptr, 8);
2441
2442 if (!ssh1_pkt_getrsakey(ssh, &servkey, &s->keystr1) ||
2443 !ssh1_pkt_getrsakey(ssh, &hostkey, &s->keystr2)) {
2444 bombout(("Failed to read SSH1 public keys from public key packet"));
2445 crStop(0);
2446 }
2447
2448 /*
2449 * Log the host key fingerprint.
2450 */
2451 {
2452 char logmsg[80];
2453 logevent("Host key fingerprint is:");
2454 strcpy(logmsg, " ");
2455 hostkey.comment = NULL;
2456 rsa_fingerprint(logmsg + strlen(logmsg),
2457 sizeof(logmsg) - strlen(logmsg), &hostkey);
2458 logevent(logmsg);
2459 }
2460
2461 ssh->v1_remote_protoflags = ssh_pkt_getuint32(ssh);
2462 s->supported_ciphers_mask = ssh_pkt_getuint32(ssh);
2463 s->supported_auths_mask = ssh_pkt_getuint32(ssh);
2464
2465 ssh->v1_local_protoflags =
2466 ssh->v1_remote_protoflags & SSH1_PROTOFLAGS_SUPPORTED;
2467 ssh->v1_local_protoflags |= SSH1_PROTOFLAG_SCREEN_NUMBER;
2468
2469 MD5Init(&md5c);
2470 MD5Update(&md5c, s->keystr2, hostkey.bytes);
2471 MD5Update(&md5c, s->keystr1, servkey.bytes);
2472 MD5Update(&md5c, cookie, 8);
2473 MD5Final(s->session_id, &md5c);
2474
2475 for (i = 0; i < 32; i++)
2476 ssh->session_key[i] = random_byte();
2477
2478 /*
2479 * Verify that the `bits' and `bytes' parameters match.
2480 */
2481 if (hostkey.bits > hostkey.bytes * 8 ||
2482 servkey.bits > servkey.bytes * 8) {
2483 bombout(("SSH1 public keys were badly formatted"));
2484 crStop(0);
2485 }
2486
2487 s->len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes);
2488
2489 s->rsabuf = snewn(s->len, unsigned char);
2490 if (!s->rsabuf)
2491 fatalbox("Out of memory");
2492
2493 /*
2494 * Verify the host key.
2495 */
2496 {
2497 /*
2498 * First format the key into a string.
2499 */
2500 int len = rsastr_len(&hostkey);
2501 char fingerprint[100];
2502 char *keystr = snewn(len, char);
2503 if (!keystr)
2504 fatalbox("Out of memory");
2505 rsastr_fmt(keystr, &hostkey);
2506 rsa_fingerprint(fingerprint, sizeof(fingerprint), &hostkey);
2507 verify_ssh_host_key(ssh->frontend,
2508 ssh->savedhost, ssh->savedport, "rsa", keystr,
2509 fingerprint);
2510 sfree(keystr);
2511 }
2512
2513 for (i = 0; i < 32; i++) {
2514 s->rsabuf[i] = ssh->session_key[i];
2515 if (i < 16)
2516 s->rsabuf[i] ^= s->session_id[i];
2517 }
2518
2519 if (hostkey.bytes > servkey.bytes) {
2520 ret = rsaencrypt(s->rsabuf, 32, &servkey);
2521 if (ret)
2522 ret = rsaencrypt(s->rsabuf, servkey.bytes, &hostkey);
2523 } else {
2524 ret = rsaencrypt(s->rsabuf, 32, &hostkey);
2525 if (ret)
2526 ret = rsaencrypt(s->rsabuf, hostkey.bytes, &servkey);
2527 }
2528 if (!ret) {
2529 bombout(("SSH1 public key encryptions failed due to bad formatting"));
2530 crStop(0);
2531 }
2532
2533 logevent("Encrypted session key");
2534
2535 {
2536 int cipher_chosen = 0, warn = 0;
2537 char *cipher_string = NULL;
2538 int i;
2539 for (i = 0; !cipher_chosen && i < CIPHER_MAX; i++) {
2540 int next_cipher = ssh->cfg.ssh_cipherlist[i];
2541 if (next_cipher == CIPHER_WARN) {
2542 /* If/when we choose a cipher, warn about it */
2543 warn = 1;
2544 } else if (next_cipher == CIPHER_AES) {
2545 /* XXX Probably don't need to mention this. */
2546 logevent("AES not supported in SSH1, skipping");
2547 } else {
2548 switch (next_cipher) {
2549 case CIPHER_3DES: s->cipher_type = SSH_CIPHER_3DES;
2550 cipher_string = "3DES"; break;
2551 case CIPHER_BLOWFISH: s->cipher_type = SSH_CIPHER_BLOWFISH;
2552 cipher_string = "Blowfish"; break;
2553 case CIPHER_DES: s->cipher_type = SSH_CIPHER_DES;
2554 cipher_string = "single-DES"; break;
2555 }
2556 if (s->supported_ciphers_mask & (1 << s->cipher_type))
2557 cipher_chosen = 1;
2558 }
2559 }
2560 if (!cipher_chosen) {
2561 if ((s->supported_ciphers_mask & (1 << SSH_CIPHER_3DES)) == 0)
2562 bombout(("Server violates SSH 1 protocol by not "
2563 "supporting 3DES encryption"));
2564 else
2565 /* shouldn't happen */
2566 bombout(("No supported ciphers found"));
2567 crStop(0);
2568 }
2569
2570 /* Warn about chosen cipher if necessary. */
2571 if (warn)
2572 askcipher(ssh->frontend, cipher_string, 0);
2573 }
2574
2575 switch (s->cipher_type) {
2576 case SSH_CIPHER_3DES:
2577 logevent("Using 3DES encryption");
2578 break;
2579 case SSH_CIPHER_DES:
2580 logevent("Using single-DES encryption");
2581 break;
2582 case SSH_CIPHER_BLOWFISH:
2583 logevent("Using Blowfish encryption");
2584 break;
2585 }
2586
2587 send_packet(ssh, SSH1_CMSG_SESSION_KEY,
2588 PKT_CHAR, s->cipher_type,
2589 PKT_DATA, cookie, 8,
2590 PKT_CHAR, (s->len * 8) >> 8, PKT_CHAR, (s->len * 8) & 0xFF,
2591 PKT_DATA, s->rsabuf, s->len,
2592 PKT_INT, ssh->v1_local_protoflags, PKT_END);
2593
2594 logevent("Trying to enable encryption...");
2595
2596 sfree(s->rsabuf);
2597
2598 ssh->cipher = (s->cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 :
2599 s->cipher_type == SSH_CIPHER_DES ? &ssh_des :
2600 &ssh_3des);
2601 ssh->v1_cipher_ctx = ssh->cipher->make_context();
2602 ssh->cipher->sesskey(ssh->v1_cipher_ctx, ssh->session_key);
2603 logeventf(ssh, "Initialised %s encryption", ssh->cipher->text_name);
2604
2605 ssh->crcda_ctx = crcda_make_context();
2606 logevent("Installing CRC compensation attack detector");
2607
2608 if (servkey.modulus) {
2609 sfree(servkey.modulus);
2610 servkey.modulus = NULL;
2611 }
2612 if (servkey.exponent) {
2613 sfree(servkey.exponent);
2614 servkey.exponent = NULL;
2615 }
2616 if (hostkey.modulus) {
2617 sfree(hostkey.modulus);
2618 hostkey.modulus = NULL;
2619 }
2620 if (hostkey.exponent) {
2621 sfree(hostkey.exponent);
2622 hostkey.exponent = NULL;
2623 }
2624 crWaitUntil(ispkt);
2625
2626 if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
2627 bombout(("Encryption not successfully enabled"));
2628 crStop(0);
2629 }
2630
2631 logevent("Successfully started encryption");
2632
2633 fflush(stdout);
2634 {
2635 if ((flags & FLAG_INTERACTIVE) && !*ssh->cfg.username) {
2636 if (ssh_get_line && !ssh_getline_pw_only) {
2637 if (!ssh_get_line("login as: ",
2638 s->username, sizeof(s->username), FALSE)) {
2639 /*
2640 * get_line failed to get a username.
2641 * Terminate.
2642 */
2643 logevent("No username provided. Abandoning session.");
2644 ssh_closing((Plug)ssh, NULL, 0, 0);
2645 crStop(1);
2646 }
2647 } else {
2648 int ret; /* need not be kept over crReturn */
2649 c_write_str(ssh, "login as: ");
2650 ssh->send_ok = 1;
2651
2652 setup_userpass_input(ssh, s->username, sizeof(s->username), 1);
2653 do {
2654 crWaitUntil(!ispkt);
2655 ret = process_userpass_input(ssh, in, inlen);
2656 } while (ret == 0);
2657 if (ret < 0)
2658 cleanup_exit(0);
2659 c_write_str(ssh, "\r\n");
2660 }
2661 } else {
2662 strncpy(s->username, ssh->cfg.username, sizeof(s->username));
2663 s->username[sizeof(s->username)-1] = '\0';
2664 }
2665
2666 send_packet(ssh, SSH1_CMSG_USER, PKT_STR, s->username, PKT_END);
2667 {
2668 char userlog[22 + sizeof(s->username)];
2669 sprintf(userlog, "Sent username \"%s\"", s->username);
2670 logevent(userlog);
2671 if (flags & FLAG_INTERACTIVE &&
2672 (!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) {
2673 strcat(userlog, "\r\n");
2674 c_write_str(ssh, userlog);
2675 }
2676 }
2677 }
2678
2679 crWaitUntil(ispkt);
2680
2681 if ((ssh->remote_bugs & BUG_CHOKES_ON_RSA)) {
2682 /* We must not attempt PK auth. Pretend we've already tried it. */
2683 s->tried_publickey = s->tried_agent = 1;
2684 } else {
2685 s->tried_publickey = s->tried_agent = 0;
2686 }
2687 s->tis_auth_refused = s->ccard_auth_refused = 0;
2688 /* Load the public half of ssh->cfg.keyfile so we notice if it's in Pageant */
2689 if (!filename_is_null(ssh->cfg.keyfile)) {
2690 if (!rsakey_pubblob(&ssh->cfg.keyfile,
2691 &s->publickey_blob, &s->publickey_bloblen, NULL))
2692 s->publickey_blob = NULL;
2693 } else
2694 s->publickey_blob = NULL;
2695
2696 while (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2697 s->pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
2698
2699 if (agent_exists() && !s->tried_agent) {
2700 /*
2701 * Attempt RSA authentication using Pageant.
2702 */
2703 void *r;
2704
2705 s->authed = FALSE;
2706 s->tried_agent = 1;
2707 logevent("Pageant is running. Requesting keys.");
2708
2709 /* Request the keys held by the agent. */
2710 PUT_32BIT(s->request, 1);
2711 s->request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES;
2712 if (!agent_query(s->request, 5, &r, &s->responselen,
2713 ssh_agent_callback, ssh)) {
2714 do {
2715 crReturn(0);
2716 if (ispkt) {
2717 bombout(("Unexpected data from server while waiting"
2718 " for agent response"));
2719 crStop(0);
2720 }
2721 } while (ispkt || inlen > 0);
2722 r = ssh->agent_response;
2723 s->responselen = ssh->agent_response_len;
2724 }
2725 s->response = (unsigned char *) r;
2726 if (s->response && s->responselen >= 5 &&
2727 s->response[4] == SSH1_AGENT_RSA_IDENTITIES_ANSWER) {
2728 s->p = s->response + 5;
2729 s->nkeys = GET_32BIT(s->p);
2730 s->p += 4;
2731 {
2732 char buf[64];
2733 sprintf(buf, "Pageant has %d SSH1 keys", s->nkeys);
2734 logevent(buf);
2735 }
2736 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
2737 {
2738 char buf[64];
2739 sprintf(buf, "Trying Pageant key #%d", s->keyi);
2740 logevent(buf);
2741 }
2742 if (s->publickey_blob &&
2743 !memcmp(s->p, s->publickey_blob,
2744 s->publickey_bloblen)) {
2745 logevent("This key matches configured key file");
2746 s->tried_publickey = 1;
2747 }
2748 s->p += 4;
2749 {
2750 int n, ok = FALSE;
2751 do { /* do while (0) to make breaking easy */
2752 n = ssh1_read_bignum
2753 (s->p, s->responselen-(s->p-s->response),
2754 &s->key.exponent);
2755 if (n < 0)
2756 break;
2757 s->p += n;
2758 n = ssh1_read_bignum
2759 (s->p, s->responselen-(s->p-s->response),
2760 &s->key.modulus);
2761 if (n < 0)
2762 break;
2763 s->p += n;
2764 if (s->responselen - (s->p-s->response) < 4)
2765 break;
2766 s->commentlen = GET_32BIT(s->p);
2767 s->p += 4;
2768 if (s->responselen - (s->p-s->response) <
2769 s->commentlen)
2770 break;
2771 s->commentp = (char *)s->p;
2772 s->p += s->commentlen;
2773 ok = TRUE;
2774 } while (0);
2775 if (!ok) {
2776 logevent("Pageant key list packet was truncated");
2777 break;
2778 }
2779 }
2780 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
2781 PKT_BIGNUM, s->key.modulus, PKT_END);
2782 crWaitUntil(ispkt);
2783 if (ssh->pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
2784 logevent("Key refused");
2785 continue;
2786 }
2787 logevent("Received RSA challenge");
2788 if ((s->challenge = ssh1_pkt_getmp(ssh)) == NULL) {
2789 bombout(("Server's RSA challenge was badly formatted"));
2790 crStop(0);
2791 }
2792
2793 {
2794 char *agentreq, *q, *ret;
2795 void *vret;
2796 int len, retlen;
2797 len = 1 + 4; /* message type, bit count */
2798 len += ssh1_bignum_length(s->key.exponent);
2799 len += ssh1_bignum_length(s->key.modulus);
2800 len += ssh1_bignum_length(s->challenge);
2801 len += 16; /* session id */
2802 len += 4; /* response format */
2803 agentreq = snewn(4 + len, char);
2804 PUT_32BIT(agentreq, len);
2805 q = agentreq + 4;
2806 *q++ = SSH1_AGENTC_RSA_CHALLENGE;
2807 PUT_32BIT(q, bignum_bitcount(s->key.modulus));
2808 q += 4;
2809 q += ssh1_write_bignum(q, s->key.exponent);
2810 q += ssh1_write_bignum(q, s->key.modulus);
2811 q += ssh1_write_bignum(q, s->challenge);
2812 memcpy(q, s->session_id, 16);
2813 q += 16;
2814 PUT_32BIT(q, 1); /* response format */
2815 if (!agent_query(agentreq, len + 4, &vret, &retlen,
2816 ssh_agent_callback, ssh)) {
2817 sfree(agentreq);
2818 do {
2819 crReturn(0);
2820 if (ispkt) {
2821 bombout(("Unexpected data from server"
2822 " while waiting for agent"
2823 " response"));
2824 crStop(0);
2825 }
2826 } while (ispkt || inlen > 0);
2827 vret = ssh->agent_response;
2828 retlen = ssh->agent_response_len;
2829 } else
2830 sfree(agentreq);
2831 ret = vret;
2832 if (ret) {
2833 if (ret[4] == SSH1_AGENT_RSA_RESPONSE) {
2834 logevent("Sending Pageant's response");
2835 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
2836 PKT_DATA, ret + 5, 16,
2837 PKT_END);
2838 sfree(ret);
2839 crWaitUntil(ispkt);
2840 if (ssh->pktin.type == SSH1_SMSG_SUCCESS) {
2841 logevent
2842 ("Pageant's response accepted");
2843 if (flags & FLAG_VERBOSE) {
2844 c_write_str(ssh, "Authenticated using"
2845 " RSA key \"");
2846 c_write(ssh, s->commentp,
2847 s->commentlen);
2848 c_write_str(ssh, "\" from agent\r\n");
2849 }
2850 s->authed = TRUE;
2851 } else
2852 logevent
2853 ("Pageant's response not accepted");
2854 } else {
2855 logevent
2856 ("Pageant failed to answer challenge");
2857 sfree(ret);
2858 }
2859 } else {
2860 logevent("No reply received from Pageant");
2861 }
2862 }
2863 freebn(s->key.exponent);
2864 freebn(s->key.modulus);
2865 freebn(s->challenge);
2866 if (s->authed)
2867 break;
2868 }
2869 sfree(s->response);
2870 }
2871 if (s->authed)
2872 break;
2873 }
2874 if (!filename_is_null(ssh->cfg.keyfile) && !s->tried_publickey)
2875 s->pwpkt_type = SSH1_CMSG_AUTH_RSA;
2876
2877 if (ssh->cfg.try_tis_auth &&
2878 (s->supported_auths_mask & (1 << SSH1_AUTH_TIS)) &&
2879 !s->tis_auth_refused) {
2880 s->pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
2881 logevent("Requested TIS authentication");
2882 send_packet(ssh, SSH1_CMSG_AUTH_TIS, PKT_END);
2883 crWaitUntil(ispkt);
2884 if (ssh->pktin.type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
2885 logevent("TIS authentication declined");
2886 if (flags & FLAG_INTERACTIVE)
2887 c_write_str(ssh, "TIS authentication refused.\r\n");
2888 s->tis_auth_refused = 1;
2889 continue;
2890 } else {
2891 char *challenge;
2892 int challengelen;
2893
2894 ssh_pkt_getstring(ssh, &challenge, &challengelen);
2895 if (!challenge) {
2896 bombout(("TIS challenge packet was badly formed"));
2897 crStop(0);
2898 }
2899 logevent("Received TIS challenge");
2900 if (challengelen > sizeof(s->prompt) - 1)
2901 challengelen = sizeof(s->prompt) - 1;/* prevent overrun */
2902 memcpy(s->prompt, challenge, challengelen);
2903 /* Prompt heuristic comes from OpenSSH */
2904 strncpy(s->prompt + challengelen,
2905 memchr(s->prompt, '\n', challengelen) ?
2906 "": "\r\nResponse: ",
2907 (sizeof s->prompt) - challengelen);
2908 s->prompt[(sizeof s->prompt) - 1] = '\0';
2909 }
2910 }
2911 if (ssh->cfg.try_tis_auth &&
2912 (s->supported_auths_mask & (1 << SSH1_AUTH_CCARD)) &&
2913 !s->ccard_auth_refused) {
2914 s->pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE;
2915 logevent("Requested CryptoCard authentication");
2916 send_packet(ssh, SSH1_CMSG_AUTH_CCARD, PKT_END);
2917 crWaitUntil(ispkt);
2918 if (ssh->pktin.type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
2919 logevent("CryptoCard authentication declined");
2920 c_write_str(ssh, "CryptoCard authentication refused.\r\n");
2921 s->ccard_auth_refused = 1;
2922 continue;
2923 } else {
2924 char *challenge;
2925 int challengelen;
2926
2927 ssh_pkt_getstring(ssh, &challenge, &challengelen);
2928 if (!challenge) {
2929 bombout(("CryptoCard challenge packet was badly formed"));
2930 crStop(0);
2931 }
2932 logevent("Received CryptoCard challenge");
2933 if (challengelen > sizeof(s->prompt) - 1)
2934 challengelen = sizeof(s->prompt) - 1;/* prevent overrun */
2935 memcpy(s->prompt, challenge, challengelen);
2936 strncpy(s->prompt + challengelen,
2937 memchr(s->prompt, '\n', challengelen) ?
2938 "" : "\r\nResponse: ",
2939 sizeof(s->prompt) - challengelen);
2940 s->prompt[sizeof(s->prompt) - 1] = '\0';
2941 }
2942 }
2943 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
2944 sprintf(s->prompt, "%.90s@%.90s's password: ",
2945 s->username, ssh->savedhost);
2946 }
2947 if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) {
2948 char *comment = NULL;
2949 int type;
2950 char msgbuf[256];
2951 if (flags & FLAG_VERBOSE)
2952 c_write_str(ssh, "Trying public key authentication.\r\n");
2953 logeventf(ssh, "Trying public key \"%s\"",
2954 filename_to_str(&ssh->cfg.keyfile));
2955 type = key_type(&ssh->cfg.keyfile);
2956 if (type != SSH_KEYTYPE_SSH1) {
2957 sprintf(msgbuf, "Key is of wrong type (%s)",
2958 key_type_to_str(type));
2959 logevent(msgbuf);
2960 c_write_str(ssh, msgbuf);
2961 c_write_str(ssh, "\r\n");
2962 s->tried_publickey = 1;
2963 continue;
2964 }
2965 if (!rsakey_encrypted(&ssh->cfg.keyfile, &comment)) {
2966 if (flags & FLAG_VERBOSE)
2967 c_write_str(ssh, "No passphrase required.\r\n");
2968 goto tryauth;
2969 }
2970 sprintf(s->prompt, "Passphrase for key \"%.100s\": ", comment);
2971 sfree(comment);
2972 }
2973
2974 /*
2975 * Show password prompt, having first obtained it via a TIS
2976 * or CryptoCard exchange if we're doing TIS or CryptoCard
2977 * authentication.
2978 */
2979 if (ssh_get_line) {
2980 if (!ssh_get_line(s->prompt, s->password,
2981 sizeof(s->password), TRUE)) {
2982 /*
2983 * get_line failed to get a password (for example
2984 * because one was supplied on the command line
2985 * which has already failed to work). Terminate.
2986 */
2987 send_packet(ssh, SSH1_MSG_DISCONNECT,
2988 PKT_STR, "No more passwords available to try",
2989 PKT_END);
2990 logevent("Unable to authenticate");
2991 connection_fatal(ssh->frontend, "Unable to authenticate");
2992 ssh_closing((Plug)ssh, NULL, 0, 0);
2993 crStop(1);
2994 }
2995 } else {
2996 /* Prompt may have come from server. We've munged it a bit, so
2997 * we know it to be zero-terminated at least once. */
2998 int ret; /* need not be saved over crReturn */
2999 c_write_untrusted(ssh, s->prompt, strlen(s->prompt));
3000 s->pos = 0;
3001
3002 setup_userpass_input(ssh, s->password, sizeof(s->password), 0);
3003 do {
3004 crWaitUntil(!ispkt);
3005 ret = process_userpass_input(ssh, in, inlen);
3006 } while (ret == 0);
3007 if (ret < 0)
3008 cleanup_exit(0);
3009 c_write_str(ssh, "\r\n");
3010 }
3011
3012 tryauth:
3013 if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) {
3014 /*
3015 * Try public key authentication with the specified
3016 * key file.
3017 */
3018 s->tried_publickey = 1;
3019
3020 {
3021 const char *error = NULL;
3022 int ret = loadrsakey(&ssh->cfg.keyfile, &s->key, s->password,
3023 &error);
3024 if (ret == 0) {
3025 c_write_str(ssh, "Couldn't load private key from ");
3026 c_write_str(ssh, filename_to_str(&ssh->cfg.keyfile));
3027 c_write_str(ssh, " (");
3028 c_write_str(ssh, error);
3029 c_write_str(ssh, ").\r\n");
3030 continue; /* go and try password */
3031 }
3032 if (ret == -1) {
3033 c_write_str(ssh, "Wrong passphrase.\r\n");
3034 s->tried_publickey = 0;
3035 continue; /* try again */
3036 }
3037 }
3038
3039 /*
3040 * Send a public key attempt.
3041 */
3042 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
3043 PKT_BIGNUM, s->key.modulus, PKT_END);
3044
3045 crWaitUntil(ispkt);
3046 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3047 c_write_str(ssh, "Server refused our public key.\r\n");
3048 continue; /* go and try password */
3049 }
3050 if (ssh->pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
3051 bombout(("Bizarre response to offer of public key"));
3052 crStop(0);
3053 }
3054
3055 {
3056 int i;
3057 unsigned char buffer[32];
3058 Bignum challenge, response;
3059
3060 if ((challenge = ssh1_pkt_getmp(ssh)) == NULL) {
3061 bombout(("Server's RSA challenge was badly formatted"));
3062 crStop(0);
3063 }
3064 response = rsadecrypt(challenge, &s->key);
3065 freebn(s->key.private_exponent);/* burn the evidence */
3066
3067 for (i = 0; i < 32; i++) {
3068 buffer[i] = bignum_byte(response, 31 - i);
3069 }
3070
3071 MD5Init(&md5c);
3072 MD5Update(&md5c, buffer, 32);
3073 MD5Update(&md5c, s->session_id, 16);
3074 MD5Final(buffer, &md5c);
3075
3076 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
3077 PKT_DATA, buffer, 16, PKT_END);
3078
3079 freebn(challenge);
3080 freebn(response);
3081 }
3082
3083 crWaitUntil(ispkt);
3084 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3085 if (flags & FLAG_VERBOSE)
3086 c_write_str(ssh, "Failed to authenticate with"
3087 " our public key.\r\n");
3088 continue; /* go and try password */
3089 } else if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
3090 bombout(("Bizarre response to RSA authentication response"));
3091 crStop(0);
3092 }
3093
3094 break; /* we're through! */
3095 } else {
3096 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
3097 /*
3098 * Defence against traffic analysis: we send a
3099 * whole bunch of packets containing strings of
3100 * different lengths. One of these strings is the
3101 * password, in a SSH1_CMSG_AUTH_PASSWORD packet.
3102 * The others are all random data in
3103 * SSH1_MSG_IGNORE packets. This way a passive
3104 * listener can't tell which is the password, and
3105 * hence can't deduce the password length.
3106 *
3107 * Anybody with a password length greater than 16
3108 * bytes is going to have enough entropy in their
3109 * password that a listener won't find it _that_
3110 * much help to know how long it is. So what we'll
3111 * do is:
3112 *
3113 * - if password length < 16, we send 15 packets
3114 * containing string lengths 1 through 15
3115 *
3116 * - otherwise, we let N be the nearest multiple
3117 * of 8 below the password length, and send 8
3118 * packets containing string lengths N through
3119 * N+7. This won't obscure the order of
3120 * magnitude of the password length, but it will
3121 * introduce a bit of extra uncertainty.
3122 *
3123 * A few servers (the old 1.2.18 through 1.2.22)
3124 * can't deal with SSH1_MSG_IGNORE. For these
3125 * servers, we need an alternative defence. We make
3126 * use of the fact that the password is interpreted
3127 * as a C string: so we can append a NUL, then some
3128 * random data.
3129 *
3130 * One server (a Cisco one) can deal with neither
3131 * SSH1_MSG_IGNORE _nor_ a padded password string.
3132 * For this server we are left with no defences
3133 * against password length sniffing.
3134 */
3135 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE)) {
3136 /*
3137 * The server can deal with SSH1_MSG_IGNORE, so
3138 * we can use the primary defence.
3139 */
3140 int bottom, top, pwlen, i;
3141 char *randomstr;
3142
3143 pwlen = strlen(s->password);
3144 if (pwlen < 16) {
3145 bottom = 0; /* zero length passwords are OK! :-) */
3146 top = 15;
3147 } else {
3148 bottom = pwlen & ~7;
3149 top = bottom + 7;
3150 }
3151
3152 assert(pwlen >= bottom && pwlen <= top);
3153
3154 randomstr = snewn(top + 1, char);
3155
3156 for (i = bottom; i <= top; i++) {
3157 if (i == pwlen)
3158 defer_packet(ssh, s->pwpkt_type,
3159 PKT_STR, s->password, PKT_END);
3160 else {
3161 for (j = 0; j < i; j++) {
3162 do {
3163 randomstr[j] = random_byte();
3164 } while (randomstr[j] == '\0');
3165 }
3166 randomstr[i] = '\0';
3167 defer_packet(ssh, SSH1_MSG_IGNORE,
3168 PKT_STR, randomstr, PKT_END);
3169 }
3170 }
3171 logevent("Sending password with camouflage packets");
3172 ssh_pkt_defersend(ssh);
3173 sfree(randomstr);
3174 }
3175 else if (!(ssh->remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) {
3176 /*
3177 * The server can't deal with SSH1_MSG_IGNORE
3178 * but can deal with padded passwords, so we
3179 * can use the secondary defence.
3180 */
3181 char string[64];
3182 char *ss;
3183 int len;
3184
3185 len = strlen(s->password);
3186 if (len < sizeof(string)) {
3187 ss = string;
3188 strcpy(string, s->password);
3189 len++; /* cover the zero byte */
3190 while (len < sizeof(string)) {
3191 string[len++] = (char) random_byte();
3192 }
3193 } else {
3194 ss = s->password;
3195 }
3196 logevent("Sending length-padded password");
3197 send_packet(ssh, s->pwpkt_type, PKT_INT, len,
3198 PKT_DATA, ss, len, PKT_END);
3199 } else {
3200 /*
3201 * The server has _both_
3202 * BUG_CHOKES_ON_SSH1_IGNORE and
3203 * BUG_NEEDS_SSH1_PLAIN_PASSWORD. There is
3204 * therefore nothing we can do.
3205 */
3206 int len;
3207 len = strlen(s->password);
3208 logevent("Sending unpadded password");
3209 send_packet(ssh, s->pwpkt_type, PKT_INT, len,
3210 PKT_DATA, s->password, len, PKT_END);
3211 }
3212 } else {
3213 send_packet(ssh, s->pwpkt_type, PKT_STR, s->password, PKT_END);
3214 }
3215 }
3216 logevent("Sent password");
3217 memset(s->password, 0, strlen(s->password));
3218 crWaitUntil(ispkt);
3219 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3220 if (flags & FLAG_VERBOSE)
3221 c_write_str(ssh, "Access denied\r\n");
3222 logevent("Authentication refused");
3223 } else if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
3224 bombout(("Strange packet received, type %d", ssh->pktin.type));
3225 crStop(0);
3226 }
3227 }
3228
3229 logevent("Authentication successful");
3230
3231 crFinish(1);
3232 }
3233
3234 void sshfwd_close(struct ssh_channel *c)
3235 {
3236 Ssh ssh = c->ssh;
3237
3238 if (ssh->state != SSH_STATE_SESSION) {
3239 assert(ssh->state == SSH_STATE_CLOSED);
3240 return;
3241 }
3242
3243 if (c && !c->closes) {
3244 /*
3245 * If the channel's remoteid is -1, we have sent
3246 * CHANNEL_OPEN for this channel, but it hasn't even been
3247 * acknowledged by the server. So we must set a close flag
3248 * on it now, and then when the server acks the channel
3249 * open, we can close it then.
3250 */
3251 if (((int)c->remoteid) != -1) {
3252 if (ssh->version == 1) {
3253 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid,
3254 PKT_END);
3255 } else {
3256 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
3257 ssh2_pkt_adduint32(ssh, c->remoteid);
3258 ssh2_pkt_send(ssh);
3259 }
3260 }
3261 c->closes = 1; /* sent MSG_CLOSE */
3262 if (c->type == CHAN_X11) {
3263 c->u.x11.s = NULL;
3264 logevent("Forwarded X11 connection terminated");
3265 } else if (c->type == CHAN_SOCKDATA ||
3266 c->type == CHAN_SOCKDATA_DORMANT) {
3267 c->u.pfd.s = NULL;
3268 logevent("Forwarded port closed");
3269 }
3270 }
3271 }
3272
3273 int sshfwd_write(struct ssh_channel *c, char *buf, int len)
3274 {
3275 Ssh ssh = c->ssh;
3276
3277 if (ssh->state != SSH_STATE_SESSION) {
3278 assert(ssh->state == SSH_STATE_CLOSED);
3279 return 0;
3280 }
3281
3282 if (ssh->version == 1) {
3283 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
3284 PKT_INT, c->remoteid,
3285 PKT_INT, len, PKT_DATA, buf, len, PKT_END);
3286 /*
3287 * In SSH1 we can return 0 here - implying that forwarded
3288 * connections are never individually throttled - because
3289 * the only circumstance that can cause throttling will be
3290 * the whole SSH connection backing up, in which case
3291 * _everything_ will be throttled as a whole.
3292 */
3293 return 0;
3294 } else {
3295 ssh2_add_channel_data(c, buf, len);
3296 return ssh2_try_send(c);
3297 }
3298 }
3299
3300 void sshfwd_unthrottle(struct ssh_channel *c, int bufsize)
3301 {
3302 Ssh ssh = c->ssh;
3303
3304 if (ssh->state != SSH_STATE_SESSION) {
3305 assert(ssh->state == SSH_STATE_CLOSED);
3306 return;
3307 }
3308
3309 if (ssh->version == 1) {
3310 if (c->v.v1.throttling && bufsize < SSH1_BUFFER_LIMIT) {
3311 c->v.v1.throttling = 0;
3312 ssh1_throttle(ssh, -1);
3313 }
3314 } else {
3315 ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
3316 }
3317 }
3318
3319 static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
3320 {
3321 crBegin(ssh->ssh1_protocol_crstate);
3322
3323 random_init();
3324
3325 while (!do_ssh1_login(ssh, in, inlen, ispkt)) {
3326 crReturnV;
3327 }
3328 if (ssh->state == SSH_STATE_CLOSED)
3329 crReturnV;
3330
3331 if (ssh->cfg.agentfwd && agent_exists()) {
3332 logevent("Requesting agent forwarding");
3333 send_packet(ssh, SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END);
3334 do {
3335 crReturnV;
3336 } while (!ispkt);
3337 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3338 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3339 bombout(("Protocol confusion"));
3340 crStopV;
3341 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3342 logevent("Agent forwarding refused");
3343 } else {
3344 logevent("Agent forwarding enabled");
3345 ssh->agentfwd_enabled = TRUE;
3346 }
3347 }
3348
3349 if (ssh->cfg.x11_forward) {
3350 char proto[20], data[64];
3351 logevent("Requesting X11 forwarding");
3352 ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
3353 data, sizeof(data), ssh->cfg.x11_auth);
3354 x11_get_real_auth(ssh->x11auth, ssh->cfg.x11_display);
3355 if (ssh->v1_local_protoflags & SSH1_PROTOFLAG_SCREEN_NUMBER) {
3356 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
3357 PKT_STR, proto, PKT_STR, data,
3358 PKT_INT, x11_get_screen_number(ssh->cfg.x11_display),
3359 PKT_END);
3360 } else {
3361 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
3362 PKT_STR, proto, PKT_STR, data, PKT_END);
3363 }
3364 do {
3365 crReturnV;
3366 } while (!ispkt);
3367 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3368 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3369 bombout(("Protocol confusion"));
3370 crStopV;
3371 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3372 logevent("X11 forwarding refused");
3373 } else {
3374 logevent("X11 forwarding enabled");
3375 ssh->X11_fwd_enabled = TRUE;
3376 }
3377 }
3378
3379 {
3380 char type;
3381 int n;
3382 int sport,dport,sserv,dserv;
3383 char sports[256], dports[256], saddr[256], host[256];
3384
3385 ssh->rportfwds = newtree234(ssh_rportcmp_ssh1);
3386 /* Add port forwardings. */
3387 ssh->portfwd_strptr = ssh->cfg.portfwd;
3388 while (*ssh->portfwd_strptr) {
3389 type = *ssh->portfwd_strptr++;
3390 saddr[0] = '\0';
3391 n = 0;
3392 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != '\t') {
3393 if (*ssh->portfwd_strptr == ':') {
3394 /*
3395 * We've seen a colon in the middle of the
3396 * source port number. This means that
3397 * everything we've seen until now is the
3398 * source _address_, so we'll move it into
3399 * saddr and start sports from the beginning
3400 * again.
3401 */
3402 ssh->portfwd_strptr++;
3403 sports[n] = '\0';
3404 strcpy(saddr, sports);
3405 n = 0;
3406 }
3407 if (n < 255) sports[n++] = *ssh->portfwd_strptr++;
3408 }
3409 sports[n] = 0;
3410 if (type != 'D') {
3411 if (*ssh->portfwd_strptr == '\t')
3412 ssh->portfwd_strptr++;
3413 n = 0;
3414 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':') {
3415 if (n < 255) host[n++] = *ssh->portfwd_strptr++;
3416 }
3417 host[n] = 0;
3418 if (*ssh->portfwd_strptr == ':')
3419 ssh->portfwd_strptr++;
3420 n = 0;
3421 while (*ssh->portfwd_strptr) {
3422 if (n < 255) dports[n++] = *ssh->portfwd_strptr++;
3423 }
3424 dports[n] = 0;
3425 ssh->portfwd_strptr++;
3426 dport = atoi(dports);
3427 dserv = 0;
3428 if (dport == 0) {
3429 dserv = 1;
3430 dport = net_service_lookup(dports);
3431 if (!dport) {
3432 logeventf(ssh, "Service lookup failed for"
3433 " destination port \"%s\"", dports);
3434 }
3435 }
3436 } else {
3437 while (*ssh->portfwd_strptr) ssh->portfwd_strptr++;
3438 dport = dserv = -1;
3439 ssh->portfwd_strptr++; /* eat the NUL and move to next one */
3440 }
3441 sport = atoi(sports);
3442 sserv = 0;
3443 if (sport == 0) {
3444 sserv = 1;
3445 sport = net_service_lookup(sports);
3446 if (!sport) {
3447 logeventf(ssh, "Service lookup failed for source"
3448 " port \"%s\"", sports);
3449 }
3450 }
3451 if (sport && dport) {
3452 /* Set up a description of the source port. */
3453 char *sportdesc = dupprintf("%.*s%.*s%.*s%.*s%d%.*s",
3454 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
3455 (int)(*saddr?1:0), ":",
3456 (int)(sserv ? strlen(sports) : 0), sports,
3457 sserv, "(", sport, sserv, ")");
3458 if (type == 'L') {
3459 /* Verbose description of the destination port */
3460 char *dportdesc = dupprintf("%s:%.*s%.*s%d%.*s",
3461 host,
3462 (int)(dserv ? strlen(dports) : 0), dports,
3463 dserv, "(", dport, dserv, ")");
3464 const char *err = pfd_addforward(host, dport,
3465 *saddr ? saddr : NULL,
3466 sport, ssh, &ssh->cfg);
3467 if (err) {
3468 logeventf(ssh, "Local port %s forward to %s"
3469 " failed: %s", sportdesc, dportdesc, err);
3470 } else {
3471 logeventf(ssh, "Local port %s forwarding to %s",
3472 sportdesc, dportdesc);
3473 }
3474 sfree(dportdesc);
3475 } else if (type == 'D') {
3476 const char *err = pfd_addforward(NULL, -1,
3477 *saddr ? saddr : NULL,
3478 sport, ssh, &ssh->cfg);
3479 if (err) {
3480 logeventf(ssh, "Local port %s SOCKS dynamic forward"
3481 " setup failed: %s", sportdesc, err);
3482 } else {
3483 logeventf(ssh, "Local port %s doing SOCKS"
3484 " dynamic forwarding", sportdesc);
3485 }
3486 } else {
3487 struct ssh_rportfwd *pf;
3488 pf = snew(struct ssh_rportfwd);
3489 strcpy(pf->dhost, host);
3490 pf->dport = dport;
3491 if (*saddr) {
3492 logeventf(ssh,
3493 "SSH1 cannot handle source address spec \"%s:%d\"; ignoring",
3494 saddr, sport);
3495 }
3496 if (add234(ssh->rportfwds, pf) != pf) {
3497 logeventf(ssh,
3498 "Duplicate remote port forwarding to %s:%d",
3499 host, dport);
3500 sfree(pf);
3501 } else {
3502 logeventf(ssh, "Requesting remote port %.*s%.*s%d%.*s"
3503 " forward to %s:%.*s%.*s%d%.*s",
3504 (int)(sserv ? strlen(sports) : 0), sports,
3505 sserv, "(", sport, sserv, ")",
3506 host,
3507 (int)(dserv ? strlen(dports) : 0), dports,
3508 dserv, "(", dport, dserv, ")");
3509 send_packet(ssh, SSH1_CMSG_PORT_FORWARD_REQUEST,
3510 PKT_INT, sport,
3511 PKT_STR, host,
3512 PKT_INT, dport,
3513 PKT_END);
3514 do {
3515 crReturnV;
3516 } while (!ispkt);
3517 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3518 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3519 bombout(("Protocol confusion"));
3520 crStopV;
3521 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3522 c_write_str(ssh, "Server refused port"
3523 " forwarding\r\n");
3524 }
3525 logevent("Remote port forwarding enabled");
3526 }
3527 }
3528 sfree(sportdesc);
3529 }
3530 }
3531 }
3532
3533 if (!ssh->cfg.nopty) {
3534 /* Unpick the terminal-speed string. */
3535 /* XXX perhaps we should allow no speeds to be sent. */
3536 ssh->ospeed = 38400; ssh->ispeed = 38400; /* last-resort defaults */
3537 sscanf(ssh->cfg.termspeed, "%d,%d", &ssh->ospeed, &ssh->ispeed);
3538 /* Send the pty request. */
3539 send_packet(ssh, SSH1_CMSG_REQUEST_PTY,
3540 PKT_STR, ssh->cfg.termtype,
3541 PKT_INT, ssh->term_height,
3542 PKT_INT, ssh->term_width,
3543 PKT_INT, 0, PKT_INT, 0, /* width,height in pixels */
3544 PKT_CHAR, 192, PKT_INT, ssh->ispeed, /* TTY_OP_ISPEED */
3545 PKT_CHAR, 193, PKT_INT, ssh->ospeed, /* TTY_OP_OSPEED */
3546 PKT_CHAR, 0, PKT_END);
3547 ssh->state = SSH_STATE_INTERMED;
3548 do {
3549 crReturnV;
3550 } while (!ispkt);
3551 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3552 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3553 bombout(("Protocol confusion"));
3554 crStopV;
3555 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3556 c_write_str(ssh, "Server refused to allocate pty\r\n");
3557 ssh->editing = ssh->echoing = 1;
3558 }
3559 logeventf(ssh, "Allocated pty (ospeed %dbps, ispeed %dbps)",
3560 ssh->ospeed, ssh->ispeed);
3561 } else {
3562 ssh->editing = ssh->echoing = 1;
3563 }
3564
3565 if (ssh->cfg.compression) {
3566 send_packet(ssh, SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END);
3567 do {
3568 crReturnV;
3569 } while (!ispkt);
3570 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3571 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3572 bombout(("Protocol confusion"));
3573 crStopV;
3574 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3575 c_write_str(ssh, "Server refused to compress\r\n");
3576 }
3577 logevent("Started compression");
3578 ssh->v1_compressing = TRUE;
3579 ssh->cs_comp_ctx = zlib_compress_init();
3580 logevent("Initialised zlib (RFC1950) compression");
3581 ssh->sc_comp_ctx = zlib_decompress_init();
3582 logevent("Initialised zlib (RFC1950) decompression");
3583 }
3584
3585 /*
3586 * Start the shell or command.
3587 *
3588 * Special case: if the first-choice command is an SSH2
3589 * subsystem (hence not usable here) and the second choice
3590 * exists, we fall straight back to that.
3591 */
3592 {
3593 char *cmd = ssh->cfg.remote_cmd_ptr;
3594
3595 if (ssh->cfg.ssh_subsys && ssh->cfg.remote_cmd_ptr2) {
3596 cmd = ssh->cfg.remote_cmd_ptr2;
3597 ssh->fallback_cmd = TRUE;
3598 }
3599 if (*cmd)
3600 send_packet(ssh, SSH1_CMSG_EXEC_CMD, PKT_STR, cmd, PKT_END);
3601 else
3602 send_packet(ssh, SSH1_CMSG_EXEC_SHELL, PKT_END);
3603 logevent("Started session");
3604 }
3605
3606 ssh->state = SSH_STATE_SESSION;
3607 if (ssh->size_needed)
3608 ssh_size(ssh, ssh->term_width, ssh->term_height);
3609 if (ssh->eof_needed)
3610 ssh_special(ssh, TS_EOF);
3611
3612 if (ssh->ldisc)
3613 ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */
3614 ssh->send_ok = 1;
3615 ssh->channels = newtree234(ssh_channelcmp);
3616 while (1) {
3617 crReturnV;
3618 if (ispkt) {
3619 if (ssh->pktin.type == SSH1_SMSG_STDOUT_DATA ||
3620 ssh->pktin.type == SSH1_SMSG_STDERR_DATA) {
3621 char *string;
3622 int stringlen, bufsize;
3623
3624 ssh_pkt_getstring(ssh, &string, &stringlen);
3625 if (string == NULL) {
3626 bombout(("Incoming terminal data packet was badly formed"));
3627 crStopV;
3628 }
3629
3630 bufsize =
3631 from_backend(ssh->frontend,
3632 ssh->pktin.type == SSH1_SMSG_STDERR_DATA,
3633 string, stringlen);
3634 if (!ssh->v1_stdout_throttling && bufsize > SSH1_BUFFER_LIMIT) {
3635 ssh->v1_stdout_throttling = 1;
3636 ssh1_throttle(ssh, +1);
3637 }
3638 } else if (ssh->pktin.type == SSH1_MSG_DISCONNECT) {
3639 ssh_closing((Plug)ssh, NULL, 0, 0);
3640 logevent("Received disconnect request");
3641 crStopV;
3642 } else if (ssh->pktin.type == SSH1_SMSG_X11_OPEN) {
3643 /* Remote side is trying to open a channel to talk to our
3644 * X-Server. Give them back a local channel number. */
3645 struct ssh_channel *c;
3646 int remoteid = ssh_pkt_getuint32(ssh);
3647
3648 logevent("Received X11 connect request");
3649 /* Refuse if X11 forwarding is disabled. */
3650 if (!ssh->X11_fwd_enabled) {
3651 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3652 PKT_INT, remoteid, PKT_END);
3653 logevent("Rejected X11 connect request");
3654 } else {
3655 c = snew(struct ssh_channel);
3656 c->ssh = ssh;
3657
3658 if (x11_init(&c->u.x11.s, ssh->cfg.x11_display, c,
3659 ssh->x11auth, NULL, -1, &ssh->cfg) != NULL) {
3660 logevent("Opening X11 forward connection failed");
3661 sfree(c);
3662 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3663 PKT_INT, remoteid, PKT_END);
3664 } else {
3665 logevent
3666 ("Opening X11 forward connection succeeded");
3667 c->remoteid = remoteid;
3668 c->localid = alloc_channel_id(ssh);
3669 c->closes = 0;
3670 c->v.v1.throttling = 0;
3671 c->type = CHAN_X11; /* identify channel type */
3672 add234(ssh->channels, c);
3673 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3674 PKT_INT, c->remoteid, PKT_INT,
3675 c->localid, PKT_END);
3676 logevent("Opened X11 forward channel");
3677 }
3678 }
3679 } else if (ssh->pktin.type == SSH1_SMSG_AGENT_OPEN) {
3680 /* Remote side is trying to open a channel to talk to our
3681 * agent. Give them back a local channel number. */
3682 struct ssh_channel *c;
3683 int remoteid = ssh_pkt_getuint32(ssh);
3684
3685 /* Refuse if agent forwarding is disabled. */
3686 if (!ssh->agentfwd_enabled) {
3687 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3688 PKT_INT, remoteid, PKT_END);
3689 } else {
3690 c = snew(struct ssh_channel);
3691 c->ssh = ssh;
3692 c->remoteid = remoteid;
3693 c->localid = alloc_channel_id(ssh);
3694 c->closes = 0;
3695 c->v.v1.throttling = 0;
3696 c->type = CHAN_AGENT; /* identify channel type */
3697 c->u.a.lensofar = 0;
3698 add234(ssh->channels, c);
3699 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3700 PKT_INT, c->remoteid, PKT_INT, c->localid,
3701 PKT_END);
3702 }
3703 } else if (ssh->pktin.type == SSH1_MSG_PORT_OPEN) {
3704 /* Remote side is trying to open a channel to talk to a
3705 * forwarded port. Give them back a local channel number. */
3706 struct ssh_channel *c;
3707 struct ssh_rportfwd pf;
3708 int remoteid;
3709 int hostsize, port;
3710 char *host, buf[1024];
3711 const char *e;
3712 c = snew(struct ssh_channel);
3713 c->ssh = ssh;
3714
3715 remoteid = ssh_pkt_getuint32(ssh);
3716 ssh_pkt_getstring(ssh, &host, &hostsize);
3717 port = ssh_pkt_getuint32(ssh);
3718
3719 if (hostsize >= lenof(pf.dhost))
3720 hostsize = lenof(pf.dhost)-1;
3721 memcpy(pf.dhost, host, hostsize);
3722 pf.dhost[hostsize] = '\0';
3723 pf.dport = port;
3724
3725 if (find234(ssh->rportfwds, &pf, NULL) == NULL) {
3726 sprintf(buf, "Rejected remote port open request for %s:%d",
3727 pf.dhost, port);
3728 logevent(buf);
3729 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3730 PKT_INT, remoteid, PKT_END);
3731 } else {
3732 sprintf(buf, "Received remote port open request for %s:%d",
3733 pf.dhost, port);
3734 logevent(buf);
3735 e = pfd_newconnect(&c->u.pfd.s, pf.dhost, port,
3736 c, &ssh->cfg);
3737 if (e != NULL) {
3738 char buf[256];
3739 sprintf(buf, "Port open failed: %s", e);
3740 logevent(buf);
3741 sfree(c);
3742 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3743 PKT_INT, remoteid, PKT_END);
3744 } else {
3745 c->remoteid = remoteid;
3746 c->localid = alloc_channel_id(ssh);
3747 c->closes = 0;
3748 c->v.v1.throttling = 0;
3749 c->type = CHAN_SOCKDATA; /* identify channel type */
3750 add234(ssh->channels, c);
3751 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3752 PKT_INT, c->remoteid, PKT_INT,
3753 c->localid, PKT_END);
3754 logevent("Forwarded port opened successfully");
3755 }
3756 }
3757
3758 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_OPEN_CONFIRMATION) {
3759 unsigned int remoteid = ssh_pkt_getuint32(ssh);
3760 unsigned int localid = ssh_pkt_getuint32(ssh);
3761 struct ssh_channel *c;
3762
3763 c = find234(ssh->channels, &remoteid, ssh_channelfind);
3764 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
3765 c->remoteid = localid;
3766 c->type = CHAN_SOCKDATA;
3767 c->v.v1.throttling = 0;
3768 pfd_confirm(c->u.pfd.s);
3769 }
3770
3771 if (c && c->closes) {
3772 /*
3773 * We have a pending close on this channel,
3774 * which we decided on before the server acked
3775 * the channel open. So now we know the
3776 * remoteid, we can close it again.
3777 */
3778 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE,
3779 PKT_INT, c->remoteid, PKT_END);
3780 }
3781
3782 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_OPEN_FAILURE) {
3783 unsigned int remoteid = ssh_pkt_getuint32(ssh);
3784 struct ssh_channel *c;
3785
3786 c = find234(ssh->channels, &remoteid, ssh_channelfind);
3787 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
3788 logevent("Forwarded connection refused by server");
3789 pfd_close(c->u.pfd.s);
3790 del234(ssh->channels, c);
3791 sfree(c);
3792 }
3793
3794 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ||
3795 ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION) {
3796 /* Remote side closes a channel. */
3797 unsigned i = ssh_pkt_getuint32(ssh);
3798 struct ssh_channel *c;
3799 c = find234(ssh->channels, &i, ssh_channelfind);
3800 if (c && ((int)c->remoteid) != -1) {
3801 int closetype;
3802 closetype =
3803 (ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ? 1 : 2);
3804
3805 if ((c->closes == 0) && (c->type == CHAN_X11)) {
3806 logevent("Forwarded X11 connection terminated");
3807 assert(c->u.x11.s != NULL);
3808 x11_close(c->u.x11.s);
3809 c->u.x11.s = NULL;
3810 }
3811 if ((c->closes == 0) && (c->type == CHAN_SOCKDATA)) {
3812 logevent("Forwarded port closed");
3813 assert(c->u.pfd.s != NULL);
3814 pfd_close(c->u.pfd.s);
3815 c->u.pfd.s = NULL;
3816 }
3817
3818 c->closes |= (closetype << 2); /* seen this message */
3819 if (!(c->closes & closetype)) {
3820 send_packet(ssh, ssh->pktin.type, PKT_INT, c->remoteid,
3821 PKT_END);
3822 c->closes |= closetype; /* sent it too */
3823 }
3824
3825 if (c->closes == 15) {
3826 del234(ssh->channels, c);
3827 sfree(c);
3828 }
3829 } else {
3830 bombout(("Received CHANNEL_CLOSE%s for %s channel %d\n",
3831 ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ? "" :
3832 "_CONFIRMATION", c ? "half-open" : "nonexistent",
3833 i));
3834 crStopV;
3835 }
3836 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_DATA) {
3837 /* Data sent down one of our channels. */
3838 int i = ssh_pkt_getuint32(ssh);
3839 char *p;
3840 int len;
3841 struct ssh_channel *c;
3842
3843 ssh_pkt_getstring(ssh, &p, &len);
3844
3845 c = find234(ssh->channels, &i, ssh_channelfind);
3846 if (c) {
3847 int bufsize = 0;
3848 switch (c->type) {
3849 case CHAN_X11:
3850 bufsize = x11_send(c->u.x11.s, p, len);
3851 break;
3852 case CHAN_SOCKDATA:
3853 bufsize = pfd_send(c->u.pfd.s, p, len);
3854 break;
3855 case CHAN_AGENT:
3856 /* Data for an agent message. Buffer it. */
3857 while (len > 0) {
3858 if (c->u.a.lensofar < 4) {
3859 int l = min(4 - c->u.a.lensofar, len);
3860 memcpy(c->u.a.msglen + c->u.a.lensofar, p,
3861 l);
3862 p += l;
3863 len -= l;
3864 c->u.a.lensofar += l;
3865 }
3866 if (c->u.a.lensofar == 4) {
3867 c->u.a.totallen =
3868 4 + GET_32BIT(c->u.a.msglen);
3869 c->u.a.message = snewn(c->u.a.totallen,
3870 unsigned char);
3871 memcpy(c->u.a.message, c->u.a.msglen, 4);
3872 }
3873 if (c->u.a.lensofar >= 4 && len > 0) {
3874 int l =
3875 min(c->u.a.totallen - c->u.a.lensofar,
3876 len);
3877 memcpy(c->u.a.message + c->u.a.lensofar, p,
3878 l);
3879 p += l;
3880 len -= l;
3881 c->u.a.lensofar += l;
3882 }
3883 if (c->u.a.lensofar == c->u.a.totallen) {
3884 void *reply;
3885 int replylen;
3886 if (agent_query(c->u.a.message,
3887 c->u.a.totallen,
3888 &reply, &replylen,
3889 ssh_agentf_callback, c))
3890 ssh_agentf_callback(c, reply, replylen);
3891 sfree(c->u.a.message);
3892 c->u.a.lensofar = 0;
3893 }
3894 }
3895 bufsize = 0; /* agent channels never back up */
3896 break;
3897 }
3898 if (!c->v.v1.throttling && bufsize > SSH1_BUFFER_LIMIT) {
3899 c->v.v1.throttling = 1;
3900 ssh1_throttle(ssh, +1);
3901 }
3902 }
3903 } else if (ssh->pktin.type == SSH1_SMSG_SUCCESS) {
3904 /* may be from EXEC_SHELL on some servers */
3905 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3906 /* may be from EXEC_SHELL on some servers
3907 * if no pty is available or in other odd cases. Ignore */
3908 } else if (ssh->pktin.type == SSH1_SMSG_EXIT_STATUS) {
3909 char buf[100];
3910 ssh->exitcode = ssh_pkt_getuint32(ssh);
3911 sprintf(buf, "Server sent command exit status %d",
3912 ssh->exitcode);
3913 logevent(buf);
3914 send_packet(ssh, SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
3915 /*
3916 * In case `helpful' firewalls or proxies tack
3917 * extra human-readable text on the end of the
3918 * session which we might mistake for another
3919 * encrypted packet, we close the session once
3920 * we've sent EXIT_CONFIRMATION.
3921 */
3922 ssh_closing((Plug)ssh, NULL, 0, 0);
3923 crStopV;
3924 } else {
3925 bombout(("Strange packet received: type %d", ssh->pktin.type));
3926 crStopV;
3927 }
3928 } else {
3929 while (inlen > 0) {
3930 int len = min(inlen, 512);
3931 send_packet(ssh, SSH1_CMSG_STDIN_DATA,
3932 PKT_INT, len, PKT_DATA, in, len, PKT_END);
3933 in += len;
3934 inlen -= len;
3935 }
3936 }
3937 }
3938
3939 crFinishV;
3940 }
3941
3942 /*
3943 * Utility routine for decoding comma-separated strings in KEXINIT.
3944 */
3945 static int in_commasep_string(char *needle, char *haystack, int haylen)
3946 {
3947 int needlen;
3948 if (!needle || !haystack) /* protect against null pointers */
3949 return 0;
3950 needlen = strlen(needle);
3951 while (1) {
3952 /*
3953 * Is it at the start of the string?
3954 */
3955 if (haylen >= needlen && /* haystack is long enough */
3956 !memcmp(needle, haystack, needlen) && /* initial match */
3957 (haylen == needlen || haystack[needlen] == ',')
3958 /* either , or EOS follows */
3959 )
3960 return 1;
3961 /*
3962 * If not, search for the next comma and resume after that.
3963 * If no comma found, terminate.
3964 */
3965 while (haylen > 0 && *haystack != ',')
3966 haylen--, haystack++;
3967 if (haylen == 0)
3968 return 0;
3969 haylen--, haystack++; /* skip over comma itself */
3970 }
3971 }
3972
3973 /*
3974 * SSH2 key creation method.
3975 */
3976 static void ssh2_mkkey(Ssh ssh, Bignum K, unsigned char *H,
3977 unsigned char *sessid, char chr,
3978 unsigned char *keyspace)
3979 {
3980 SHA_State s;
3981 /* First 20 bytes. */
3982 SHA_Init(&s);
3983 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
3984 sha_mpint(&s, K);
3985 SHA_Bytes(&s, H, 20);
3986 SHA_Bytes(&s, &chr, 1);
3987 SHA_Bytes(&s, sessid, 20);
3988 SHA_Final(&s, keyspace);
3989 /* Next 20 bytes. */
3990 SHA_Init(&s);
3991 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
3992 sha_mpint(&s, K);
3993 SHA_Bytes(&s, H, 20);
3994 SHA_Bytes(&s, keyspace, 20);
3995 SHA_Final(&s, keyspace + 20);
3996 }
3997
3998 /*
3999 * Handle the SSH2 transport layer.
4000 */
4001 static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
4002 {
4003 struct do_ssh2_transport_state {
4004 int nbits, pbits, warn;
4005 Bignum p, g, e, f, K;
4006 int kex_init_value, kex_reply_value;
4007 const struct ssh_mac **maclist;
4008 int nmacs;
4009 const struct ssh2_cipher *cscipher_tobe;
4010 const struct ssh2_cipher *sccipher_tobe;
4011 const struct ssh_mac *csmac_tobe;
4012 const struct ssh_mac *scmac_tobe;
4013 const struct ssh_compress *cscomp_tobe;
4014 const struct ssh_compress *sccomp_tobe;
4015 char *hostkeydata, *sigdata, *keystr, *fingerprint;
4016 int hostkeylen, siglen;
4017 void *hkey; /* actual host key */
4018 unsigned char exchange_hash[20];
4019 int n_preferred_ciphers;
4020 const struct ssh2_ciphers *preferred_ciphers[CIPHER_MAX];
4021 const struct ssh_compress *preferred_comp;
4022 int first_kex;
4023 };
4024 crState(do_ssh2_transport_state);
4025
4026 crBegin(ssh->do_ssh2_transport_crstate);
4027
4028 s->cscipher_tobe = s->sccipher_tobe = NULL;
4029 s->csmac_tobe = s->scmac_tobe = NULL;
4030 s->cscomp_tobe = s->sccomp_tobe = NULL;
4031
4032 random_init();
4033 s->first_kex = 1;
4034
4035 {
4036 int i;
4037 /*
4038 * Set up the preferred ciphers. (NULL => warn below here)
4039 */
4040 s->n_preferred_ciphers = 0;
4041 for (i = 0; i < CIPHER_MAX; i++) {
4042 switch (ssh->cfg.ssh_cipherlist[i]) {
4043 case CIPHER_BLOWFISH:
4044 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_blowfish;
4045 break;
4046 case CIPHER_DES:
4047 if (ssh->cfg.ssh2_des_cbc) {
4048 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_des;
4049 }
4050 break;
4051 case CIPHER_3DES:
4052 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_3des;
4053 break;
4054 case CIPHER_AES:
4055 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_aes;
4056 break;
4057 case CIPHER_WARN:
4058 /* Flag for later. Don't bother if it's the last in
4059 * the list. */
4060 if (i < CIPHER_MAX - 1) {
4061 s->preferred_ciphers[s->n_preferred_ciphers++] = NULL;
4062 }
4063 break;
4064 }
4065 }
4066 }
4067
4068 /*
4069 * Set up preferred compression.
4070 */
4071 if (ssh->cfg.compression)
4072 s->preferred_comp = &ssh_zlib;
4073 else
4074 s->preferred_comp = &ssh_comp_none;
4075
4076 /*
4077 * Be prepared to work around the buggy MAC problem.
4078 */
4079 if (ssh->remote_bugs & BUG_SSH2_HMAC)
4080 s->maclist = buggymacs, s->nmacs = lenof(buggymacs);
4081 else
4082 s->maclist = macs, s->nmacs = lenof(macs);
4083
4084 begin_key_exchange:
4085 {
4086 int i, j, cipherstr_started;
4087
4088 /*
4089 * Construct and send our key exchange packet.
4090 */
4091 ssh2_pkt_init(ssh, SSH2_MSG_KEXINIT);
4092 for (i = 0; i < 16; i++)
4093 ssh2_pkt_addbyte(ssh, (unsigned char) random_byte());
4094 /* List key exchange algorithms. */
4095 ssh2_pkt_addstring_start(ssh);
4096 for (i = 0; i < lenof(kex_algs); i++) {
4097 if (kex_algs[i] == &ssh_diffiehellman_gex &&
4098 (ssh->remote_bugs & BUG_SSH2_DH_GEX))
4099 continue;
4100 ssh2_pkt_addstring_str(ssh, kex_algs[i]->name);
4101 if (i < lenof(kex_algs) - 1)
4102 ssh2_pkt_addstring_str(ssh, ",");
4103 }
4104 /* List server host key algorithms. */
4105 ssh2_pkt_addstring_start(ssh);
4106 for (i = 0; i < lenof(hostkey_algs); i++) {
4107 ssh2_pkt_addstring_str(ssh, hostkey_algs[i]->name);
4108 if (i < lenof(hostkey_algs) - 1)
4109 ssh2_pkt_addstring_str(ssh, ",");
4110 }
4111 /* List client->server encryption algorithms. */
4112 ssh2_pkt_addstring_start(ssh);
4113 cipherstr_started = 0;
4114 for (i = 0; i < s->n_preferred_ciphers; i++) {
4115 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
4116 if (!c) continue; /* warning flag */
4117 for (j = 0; j < c->nciphers; j++) {
4118 if (cipherstr_started)
4119 ssh2_pkt_addstring_str(ssh, ",");
4120 ssh2_pkt_addstring_str(ssh, c->list[j]->name);
4121 cipherstr_started = 1;
4122 }
4123 }
4124 /* List server->client encryption algorithms. */
4125 ssh2_pkt_addstring_start(ssh);
4126 cipherstr_started = 0;
4127 for (i = 0; i < s->n_preferred_ciphers; i++) {
4128 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
4129 if (!c) continue; /* warning flag */
4130 for (j = 0; j < c->nciphers; j++) {
4131 if (cipherstr_started)
4132 ssh2_pkt_addstring_str(ssh, ",");
4133 ssh2_pkt_addstring_str(ssh, c->list[j]->name);
4134 cipherstr_started = 1;
4135 }
4136 }
4137 /* List client->server MAC algorithms. */
4138 ssh2_pkt_addstring_start(ssh);
4139 for (i = 0; i < s->nmacs; i++) {
4140 ssh2_pkt_addstring_str(ssh, s->maclist[i]->name);
4141 if (i < s->nmacs - 1)
4142 ssh2_pkt_addstring_str(ssh, ",");
4143 }
4144 /* List server->client MAC algorithms. */
4145 ssh2_pkt_addstring_start(ssh);
4146 for (i = 0; i < s->nmacs; i++) {
4147 ssh2_pkt_addstring_str(ssh, s->maclist[i]->name);
4148 if (i < s->nmacs - 1)
4149 ssh2_pkt_addstring_str(ssh, ",");
4150 }
4151 /* List client->server compression algorithms. */
4152 ssh2_pkt_addstring_start(ssh);
4153 assert(lenof(compressions) > 1);
4154 ssh2_pkt_addstring_str(ssh, s->preferred_comp->name);
4155 for (i = 0; i < lenof(compressions); i++) {
4156 const struct ssh_compress *c = compressions[i];
4157 if (c != s->preferred_comp) {
4158 ssh2_pkt_addstring_str(ssh, ",");
4159 ssh2_pkt_addstring_str(ssh, c->name);
4160 }
4161 }
4162 /* List server->client compression algorithms. */
4163 ssh2_pkt_addstring_start(ssh);
4164 assert(lenof(compressions) > 1);
4165 ssh2_pkt_addstring_str(ssh, s->preferred_comp->name);
4166 for (i = 0; i < lenof(compressions); i++) {
4167 const struct ssh_compress *c = compressions[i];
4168 if (c != s->preferred_comp) {
4169 ssh2_pkt_addstring_str(ssh, ",");
4170 ssh2_pkt_addstring_str(ssh, c->name);
4171 }
4172 }
4173 /* List client->server languages. Empty list. */
4174 ssh2_pkt_addstring_start(ssh);
4175 /* List server->client languages. Empty list. */
4176 ssh2_pkt_addstring_start(ssh);
4177 /* First KEX packet does _not_ follow, because we're not that brave. */
4178 ssh2_pkt_addbool(ssh, FALSE);
4179 /* Reserved. */
4180 ssh2_pkt_adduint32(ssh, 0);
4181 }
4182
4183 ssh->exhash = ssh->exhashbase;
4184 sha_string(&ssh->exhash, ssh->pktout.data + 5, ssh->pktout.length - 5);
4185
4186 ssh2_pkt_send(ssh);
4187
4188 if (!ispkt)
4189 crWaitUntil(ispkt);
4190 if (ssh->pktin.length > 5)
4191 sha_string(&ssh->exhash, ssh->pktin.data + 5, ssh->pktin.length - 5);
4192
4193 /*
4194 * Now examine the other side's KEXINIT to see what we're up
4195 * to.
4196 */
4197 {
4198 char *str;
4199 int i, j, len;
4200
4201 if (ssh->pktin.type != SSH2_MSG_KEXINIT) {
4202 bombout(("expected key exchange packet from server"));
4203 crStop(0);
4204 }
4205 ssh->kex = NULL;
4206 ssh->hostkey = NULL;
4207 s->cscipher_tobe = NULL;
4208 s->sccipher_tobe = NULL;
4209 s->csmac_tobe = NULL;
4210 s->scmac_tobe = NULL;
4211 s->cscomp_tobe = NULL;
4212 s->sccomp_tobe = NULL;
4213 ssh->pktin.savedpos += 16; /* skip garbage cookie */
4214 ssh_pkt_getstring(ssh, &str, &len); /* key exchange algorithms */
4215 for (i = 0; i < lenof(kex_algs); i++) {
4216 if (kex_algs[i] == &ssh_diffiehellman_gex &&
4217 (ssh->remote_bugs & BUG_SSH2_DH_GEX))
4218 continue;
4219 if (in_commasep_string(kex_algs[i]->name, str, len)) {
4220 ssh->kex = kex_algs[i];
4221 break;
4222 }
4223 }
4224 ssh_pkt_getstring(ssh, &str, &len); /* host key algorithms */
4225 for (i = 0; i < lenof(hostkey_algs); i++) {
4226 if (in_commasep_string(hostkey_algs[i]->name, str, len)) {
4227 ssh->hostkey = hostkey_algs[i];
4228 break;
4229 }
4230 }
4231 ssh_pkt_getstring(ssh, &str, &len); /* client->server cipher */
4232 s->warn = 0;
4233 for (i = 0; i < s->n_preferred_ciphers; i++) {
4234 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
4235 if (!c) {
4236 s->warn = 1;
4237 } else {
4238 for (j = 0; j < c->nciphers; j++) {
4239 if (in_commasep_string(c->list[j]->name, str, len)) {
4240 s->cscipher_tobe = c->list[j];
4241 break;
4242 }
4243 }
4244 }
4245 if (s->cscipher_tobe) {
4246 if (s->warn)
4247 askcipher(ssh->frontend, s->cscipher_tobe->name, 1);
4248 break;
4249 }
4250 }
4251 if (!s->cscipher_tobe) {
4252 bombout(("Couldn't agree a client-to-server cipher (available: %s)",
4253 str ? str : "(null)"));
4254 crStop(0);
4255 }
4256
4257 ssh_pkt_getstring(ssh, &str, &len); /* server->client cipher */
4258 s->warn = 0;
4259 for (i = 0; i < s->n_preferred_ciphers; i++) {
4260 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
4261 if (!c) {
4262 s->warn = 1;
4263 } else {
4264 for (j = 0; j < c->nciphers; j++) {
4265 if (in_commasep_string(c->list[j]->name, str, len)) {
4266 s->sccipher_tobe = c->list[j];
4267 break;
4268 }
4269 }
4270 }
4271 if (s->sccipher_tobe) {
4272 if (s->warn)
4273 askcipher(ssh->frontend, s->sccipher_tobe->name, 2);
4274 break;
4275 }
4276 }
4277 if (!s->sccipher_tobe) {
4278 bombout(("Couldn't agree a server-to-client cipher (available: %s)",
4279 str ? str : "(null)"));
4280 crStop(0);
4281 }
4282
4283 ssh_pkt_getstring(ssh, &str, &len); /* client->server mac */
4284 for (i = 0; i < s->nmacs; i++) {
4285 if (in_commasep_string(s->maclist[i]->name, str, len)) {
4286 s->csmac_tobe = s->maclist[i];
4287 break;
4288 }
4289 }
4290 ssh_pkt_getstring(ssh, &str, &len); /* server->client mac */
4291 for (i = 0; i < s->nmacs; i++) {
4292 if (in_commasep_string(s->maclist[i]->name, str, len)) {
4293 s->scmac_tobe = s->maclist[i];
4294 break;
4295 }
4296 }
4297 ssh_pkt_getstring(ssh, &str, &len); /* client->server compression */
4298 for (i = 0; i < lenof(compressions) + 1; i++) {
4299 const struct ssh_compress *c =
4300 i == 0 ? s->preferred_comp : compressions[i - 1];
4301 if (in_commasep_string(c->name, str, len)) {
4302 s->cscomp_tobe = c;
4303 break;
4304 }
4305 }
4306 ssh_pkt_getstring(ssh, &str, &len); /* server->client compression */
4307 for (i = 0; i < lenof(compressions) + 1; i++) {
4308 const struct ssh_compress *c =
4309 i == 0 ? s->preferred_comp : compressions[i - 1];
4310 if (in_commasep_string(c->name, str, len)) {
4311 s->sccomp_tobe = c;
4312 break;
4313 }
4314 }
4315 }
4316
4317 /*
4318 * Work out the number of bits of key we will need from the key
4319 * exchange. We start with the maximum key length of either
4320 * cipher...
4321 */
4322 {
4323 int csbits, scbits;
4324
4325 csbits = s->cscipher_tobe->keylen;
4326 scbits = s->sccipher_tobe->keylen;
4327 s->nbits = (csbits > scbits ? csbits : scbits);
4328 }
4329 /* The keys only have 160-bit entropy, since they're based on
4330 * a SHA-1 hash. So cap the key size at 160 bits. */
4331 if (s->nbits > 160)
4332 s->nbits = 160;
4333
4334 /*
4335 * If we're doing Diffie-Hellman group exchange, start by
4336 * requesting a group.
4337 */
4338 if (ssh->kex == &ssh_diffiehellman_gex) {
4339 logevent("Doing Diffie-Hellman group exchange");
4340 ssh->pkt_ctx |= SSH2_PKTCTX_DHGEX;
4341 /*
4342 * Work out how big a DH group we will need to allow that
4343 * much data.
4344 */
4345 s->pbits = 512 << ((s->nbits - 1) / 64);
4346 ssh2_pkt_init(ssh, SSH2_MSG_KEX_DH_GEX_REQUEST);
4347 ssh2_pkt_adduint32(ssh, s->pbits);
4348 ssh2_pkt_send(ssh);
4349
4350 crWaitUntil(ispkt);
4351 if (ssh->pktin.type != SSH2_MSG_KEX_DH_GEX_GROUP) {
4352 bombout(("expected key exchange group packet from server"));
4353 crStop(0);
4354 }
4355 s->p = ssh2_pkt_getmp(ssh);
4356 s->g = ssh2_pkt_getmp(ssh);
4357 ssh->kex_ctx = dh_setup_group(s->p, s->g);
4358 s->kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT;
4359 s->kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY;
4360 } else {
4361 ssh->pkt_ctx |= SSH2_PKTCTX_DHGROUP1;
4362 ssh->kex_ctx = dh_setup_group1();
4363 s->kex_init_value = SSH2_MSG_KEXDH_INIT;
4364 s->kex_reply_value = SSH2_MSG_KEXDH_REPLY;
4365 }
4366
4367 logevent("Doing Diffie-Hellman key exchange");
4368 /*
4369 * Now generate and send e for Diffie-Hellman.
4370 */
4371 s->e = dh_create_e(ssh->kex_ctx, s->nbits * 2);
4372 ssh2_pkt_init(ssh, s->kex_init_value);
4373 ssh2_pkt_addmp(ssh, s->e);
4374 ssh2_pkt_send(ssh);
4375
4376 crWaitUntil(ispkt);
4377 if (ssh->pktin.type != s->kex_reply_value) {
4378 bombout(("expected key exchange reply packet from server"));
4379 crStop(0);
4380 }
4381 ssh_pkt_getstring(ssh, &s->hostkeydata, &s->hostkeylen);
4382 s->f = ssh2_pkt_getmp(ssh);
4383 ssh_pkt_getstring(ssh, &s->sigdata, &s->siglen);
4384
4385 s->K = dh_find_K(ssh->kex_ctx, s->f);
4386
4387 sha_string(&ssh->exhash, s->hostkeydata, s->hostkeylen);
4388 if (ssh->kex == &ssh_diffiehellman_gex) {
4389 sha_uint32(&ssh->exhash, s->pbits);
4390 sha_mpint(&ssh->exhash, s->p);
4391 sha_mpint(&ssh->exhash, s->g);
4392 }
4393 sha_mpint(&ssh->exhash, s->e);
4394 sha_mpint(&ssh->exhash, s->f);
4395 sha_mpint(&ssh->exhash, s->K);
4396 SHA_Final(&ssh->exhash, s->exchange_hash);
4397
4398 dh_cleanup(ssh->kex_ctx);
4399 ssh->kex_ctx = NULL;
4400
4401 #if 0
4402 debug(("Exchange hash is:\n"));
4403 dmemdump(s->exchange_hash, 20);
4404 #endif
4405
4406 s->hkey = ssh->hostkey->newkey(s->hostkeydata, s->hostkeylen);
4407 if (!s->hkey ||
4408 !ssh->hostkey->verifysig(s->hkey, s->sigdata, s->siglen,
4409 (char *)s->exchange_hash, 20)) {
4410 bombout(("Server's host key did not match the signature supplied"));
4411 crStop(0);
4412 }
4413
4414 /*
4415 * Authenticate remote host: verify host key. (We've already
4416 * checked the signature of the exchange hash.)
4417 */
4418 s->keystr = ssh->hostkey->fmtkey(s->hkey);
4419 s->fingerprint = ssh->hostkey->fingerprint(s->hkey);
4420 verify_ssh_host_key(ssh->frontend,
4421 ssh->savedhost, ssh->savedport, ssh->hostkey->keytype,
4422 s->keystr, s->fingerprint);
4423 if (s->first_kex) { /* don't bother logging this in rekeys */
4424 logevent("Host key fingerprint is:");
4425 logevent(s->fingerprint);
4426 }
4427 sfree(s->fingerprint);
4428 sfree(s->keystr);
4429 ssh->hostkey->freekey(s->hkey);
4430
4431 /*
4432 * Send SSH2_MSG_NEWKEYS.
4433 */
4434 ssh2_pkt_init(ssh, SSH2_MSG_NEWKEYS);
4435 ssh2_pkt_send(ssh);
4436
4437 /*
4438 * Expect SSH2_MSG_NEWKEYS from server.
4439 */
4440 crWaitUntil(ispkt);
4441 if (ssh->pktin.type != SSH2_MSG_NEWKEYS) {
4442 bombout(("expected new-keys packet from server"));
4443 crStop(0);
4444 }
4445
4446 /*
4447 * Create and initialise session keys.
4448 */
4449 if (ssh->cs_cipher_ctx)
4450 ssh->cscipher->free_context(ssh->cs_cipher_ctx);
4451 ssh->cscipher = s->cscipher_tobe;
4452 ssh->cs_cipher_ctx = ssh->cscipher->make_context();
4453
4454 if (ssh->sc_cipher_ctx)
4455 ssh->sccipher->free_context(ssh->sc_cipher_ctx);
4456 ssh->sccipher = s->sccipher_tobe;
4457 ssh->sc_cipher_ctx = ssh->sccipher->make_context();
4458
4459 if (ssh->cs_mac_ctx)
4460 ssh->csmac->free_context(ssh->cs_mac_ctx);
4461 ssh->csmac = s->csmac_tobe;
4462 ssh->cs_mac_ctx = ssh->csmac->make_context();
4463
4464 if (ssh->sc_mac_ctx)
4465 ssh->scmac->free_context(ssh->sc_mac_ctx);
4466 ssh->scmac = s->scmac_tobe;
4467 ssh->sc_mac_ctx = ssh->scmac->make_context();
4468
4469 if (ssh->cs_comp_ctx)
4470 ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
4471 ssh->cscomp = s->cscomp_tobe;
4472 ssh->cs_comp_ctx = ssh->cscomp->compress_init();
4473
4474 if (ssh->sc_comp_ctx)
4475 ssh->sccomp->decompress_cleanup(ssh->sc_comp_ctx);
4476 ssh->sccomp = s->sccomp_tobe;
4477 ssh->sc_comp_ctx = ssh->sccomp->decompress_init();
4478
4479 /*
4480 * Set IVs after keys. Here we use the exchange hash from the
4481 * _first_ key exchange.
4482 */
4483 {
4484 unsigned char keyspace[40];
4485 if (s->first_kex)
4486 memcpy(ssh->v2_session_id, s->exchange_hash,
4487 sizeof(s->exchange_hash));
4488 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'C',keyspace);
4489 ssh->cscipher->setkey(ssh->cs_cipher_ctx, keyspace);
4490 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'D',keyspace);
4491 ssh->sccipher->setkey(ssh->sc_cipher_ctx, keyspace);
4492 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'A',keyspace);
4493 ssh->cscipher->setiv(ssh->cs_cipher_ctx, keyspace);
4494 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'B',keyspace);
4495 ssh->sccipher->setiv(ssh->sc_cipher_ctx, keyspace);
4496 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'E',keyspace);
4497 ssh->csmac->setkey(ssh->cs_mac_ctx, keyspace);
4498 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'F',keyspace);
4499 ssh->scmac->setkey(ssh->sc_mac_ctx, keyspace);
4500 }
4501 logeventf(ssh, "Initialised %.200s client->server encryption",
4502 ssh->cscipher->text_name);
4503 logeventf(ssh, "Initialised %.200s server->client encryption",
4504 ssh->sccipher->text_name);
4505 if (ssh->cscomp->text_name)
4506 logeventf(ssh, "Initialised %s compression",
4507 ssh->cscomp->text_name);
4508 if (ssh->sccomp->text_name)
4509 logeventf(ssh, "Initialised %s decompression",
4510 ssh->sccomp->text_name);
4511 freebn(s->f);
4512 freebn(s->K);
4513 if (ssh->kex == &ssh_diffiehellman_gex) {
4514 freebn(s->g);
4515 freebn(s->p);
4516 }
4517
4518 /*
4519 * If this is the first key exchange phase, we must pass the
4520 * SSH2_MSG_NEWKEYS packet to the next layer, not because it
4521 * wants to see it but because it will need time to initialise
4522 * itself before it sees an actual packet. In subsequent key
4523 * exchange phases, we don't pass SSH2_MSG_NEWKEYS on, because
4524 * it would only confuse the layer above.
4525 */
4526 if (!s->first_kex) {
4527 crReturn(0);
4528 }
4529 s->first_kex = 0;
4530
4531 /*
4532 * Now we're encrypting. Begin returning 1 to the protocol main
4533 * function so that other things can run on top of the
4534 * transport. If we ever see a KEXINIT, we must go back to the
4535 * start.
4536 */
4537 while (!(ispkt && ssh->pktin.type == SSH2_MSG_KEXINIT)) {
4538 crReturn(1);
4539 }
4540 logevent("Server initiated key re-exchange");
4541 goto begin_key_exchange;
4542
4543 crFinish(1);
4544 }
4545
4546 /*
4547 * Add data to an SSH2 channel output buffer.
4548 */
4549 static void ssh2_add_channel_data(struct ssh_channel *c, char *buf,
4550 int len)
4551 {
4552 bufchain_add(&c->v.v2.outbuffer, buf, len);
4553 }
4554
4555 /*
4556 * Attempt to send data on an SSH2 channel.
4557 */
4558 static int ssh2_try_send(struct ssh_channel *c)
4559 {
4560 Ssh ssh = c->ssh;
4561
4562 while (c->v.v2.remwindow > 0 && bufchain_size(&c->v.v2.outbuffer) > 0) {
4563 int len;
4564 void *data;
4565 bufchain_prefix(&c->v.v2.outbuffer, &data, &len);
4566 if ((unsigned)len > c->v.v2.remwindow)
4567 len = c->v.v2.remwindow;
4568 if ((unsigned)len > c->v.v2.remmaxpkt)
4569 len = c->v.v2.remmaxpkt;
4570 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_DATA);
4571 ssh2_pkt_adduint32(ssh, c->remoteid);
4572 ssh2_pkt_addstring_start(ssh);
4573 ssh2_pkt_addstring_data(ssh, data, len);
4574 ssh2_pkt_send(ssh);
4575 bufchain_consume(&c->v.v2.outbuffer, len);
4576 c->v.v2.remwindow -= len;
4577 }
4578
4579 /*
4580 * After having sent as much data as we can, return the amount
4581 * still buffered.
4582 */
4583 return bufchain_size(&c->v.v2.outbuffer);
4584 }
4585
4586 /*
4587 * Potentially enlarge the window on an SSH2 channel.
4588 */
4589 static void ssh2_set_window(struct ssh_channel *c, unsigned newwin)
4590 {
4591 Ssh ssh = c->ssh;
4592
4593 /*
4594 * Never send WINDOW_ADJUST for a channel that the remote side
4595 * already thinks it's closed; there's no point, since it won't
4596 * be sending any more data anyway.
4597 */
4598 if (c->closes != 0)
4599 return;
4600
4601 if (newwin > c->v.v2.locwindow) {
4602 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST);
4603 ssh2_pkt_adduint32(ssh, c->remoteid);
4604 ssh2_pkt_adduint32(ssh, newwin - c->v.v2.locwindow);
4605 ssh2_pkt_send(ssh);
4606 c->v.v2.locwindow = newwin;
4607 }
4608 }
4609
4610 /*
4611 * Handle the SSH2 userauth and connection layers.
4612 */
4613 static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
4614 {
4615 struct do_ssh2_authconn_state {
4616 enum {
4617 AUTH_INVALID, AUTH_PUBLICKEY_AGENT, AUTH_PUBLICKEY_FILE,
4618 AUTH_PASSWORD,
4619 AUTH_KEYBOARD_INTERACTIVE
4620 } method;
4621 enum {
4622 AUTH_TYPE_NONE,
4623 AUTH_TYPE_PUBLICKEY,
4624 AUTH_TYPE_PUBLICKEY_OFFER_LOUD,
4625 AUTH_TYPE_PUBLICKEY_OFFER_QUIET,
4626 AUTH_TYPE_PASSWORD,
4627 AUTH_TYPE_KEYBOARD_INTERACTIVE,
4628 AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET
4629 } type;
4630 int gotit, need_pw, can_pubkey, can_passwd, can_keyb_inter;
4631 int tried_pubkey_config, tried_agent, tried_keyb_inter;
4632 int kbd_inter_running;
4633 int we_are_in;
4634 int num_prompts, curr_prompt, echo;
4635 char username[100];
4636 int got_username;
4637 char pwprompt[512];
4638 char password[100];
4639 void *publickey_blob;
4640 int publickey_bloblen;
4641 unsigned char request[5], *response, *p;
4642 int responselen;
4643 int keyi, nkeys;
4644 int authed;
4645 char *pkblob, *alg, *commentp;
4646 int pklen, alglen, commentlen;
4647 int siglen, retlen, len;
4648 char *q, *agentreq, *ret;
4649 int try_send;
4650 };
4651 crState(do_ssh2_authconn_state);
4652
4653 crBegin(ssh->do_ssh2_authconn_crstate);
4654
4655 /*
4656 * Request userauth protocol, and await a response to it.
4657 */
4658 ssh2_pkt_init(ssh, SSH2_MSG_SERVICE_REQUEST);
4659 ssh2_pkt_addstring(ssh, "ssh-userauth");
4660 ssh2_pkt_send(ssh);
4661 crWaitUntilV(ispkt);
4662 if (ssh->pktin.type != SSH2_MSG_SERVICE_ACCEPT) {
4663 bombout(("Server refused user authentication protocol"));
4664 crStopV;
4665 }
4666
4667 /*
4668 * We repeat this whole loop, including the username prompt,
4669 * until we manage a successful authentication. If the user
4670 * types the wrong _password_, they can be sent back to the
4671 * beginning to try another username, if this is configured on.
4672 * (If they specify a username in the config, they are never
4673 * asked, even if they do give a wrong password.)
4674 *
4675 * I think this best serves the needs of
4676 *
4677 * - the people who have no configuration, no keys, and just
4678 * want to try repeated (username,password) pairs until they
4679 * type both correctly
4680 *
4681 * - people who have keys and configuration but occasionally
4682 * need to fall back to passwords
4683 *
4684 * - people with a key held in Pageant, who might not have
4685 * logged in to a particular machine before; so they want to
4686 * type a username, and then _either_ their key will be
4687 * accepted, _or_ they will type a password. If they mistype
4688 * the username they will want to be able to get back and
4689 * retype it!
4690 */
4691 s->username[0] = '\0';
4692 s->got_username = FALSE;
4693 do {
4694 /*
4695 * Get a username.
4696 */
4697 if (s->got_username && !ssh->cfg.change_username) {
4698 /*
4699 * We got a username last time round this loop, and
4700 * with change_username turned off we don't try to get
4701 * it again.
4702 */
4703 } else if ((flags & FLAG_INTERACTIVE) && !*ssh->cfg.username) {
4704 if (ssh_get_line && !ssh_getline_pw_only) {
4705 if (!ssh_get_line("login as: ",
4706 s->username, sizeof(s->username), FALSE)) {
4707 /*
4708 * get_line failed to get a username.
4709 * Terminate.
4710 */
4711 logevent("No username provided. Abandoning session.");
4712 ssh_closing((Plug)ssh, NULL, 0, 0);
4713 crStopV;
4714 }
4715 } else {
4716 int ret; /* need not be saved across crReturn */
4717 c_write_str(ssh, "login as: ");
4718 ssh->send_ok = 1;
4719 setup_userpass_input(ssh, s->username, sizeof(s->username), 1);
4720 do {
4721 crWaitUntilV(!ispkt);
4722 ret = process_userpass_input(ssh, in, inlen);
4723 } while (ret == 0);
4724 if (ret < 0)
4725 cleanup_exit(0);
4726 c_write_str(ssh, "\r\n");
4727 }
4728 s->username[strcspn(s->username, "\n\r")] = '\0';
4729 } else {
4730 char *stuff;
4731 strncpy(s->username, ssh->cfg.username, sizeof(s->username));
4732 s->username[sizeof(s->username)-1] = '\0';
4733 if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
4734 stuff = dupprintf("Using username \"%s\".\r\n", s->username);
4735 c_write_str(ssh, stuff);
4736 sfree(stuff);
4737 }
4738 }
4739 s->got_username = TRUE;
4740
4741 /*
4742 * Send an authentication request using method "none": (a)
4743 * just in case it succeeds, and (b) so that we know what
4744 * authentication methods we can usefully try next.
4745 */
4746 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4747
4748 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4749 ssh2_pkt_addstring(ssh, s->username);
4750 ssh2_pkt_addstring(ssh, "ssh-connection");/* service requested */
4751 ssh2_pkt_addstring(ssh, "none"); /* method */
4752 ssh2_pkt_send(ssh);
4753 s->type = AUTH_TYPE_NONE;
4754 s->gotit = FALSE;
4755 s->we_are_in = FALSE;
4756
4757 s->tried_pubkey_config = FALSE;
4758 s->tried_agent = FALSE;
4759 s->tried_keyb_inter = FALSE;
4760 s->kbd_inter_running = FALSE;
4761 /* Load the pub half of ssh->cfg.keyfile so we notice if it's in Pageant */
4762 if (!filename_is_null(ssh->cfg.keyfile)) {
4763 int keytype;
4764 logeventf(ssh, "Reading private key file \"%.150s\"",
4765 filename_to_str(&ssh->cfg.keyfile));
4766 keytype = key_type(&ssh->cfg.keyfile);
4767 if (keytype == SSH_KEYTYPE_SSH2) {
4768 s->publickey_blob =
4769 ssh2_userkey_loadpub(&ssh->cfg.keyfile, NULL,
4770 &s->publickey_bloblen, NULL);
4771 } else {
4772 char *msgbuf;
4773 logeventf(ssh, "Unable to use this key file (%s)",
4774 key_type_to_str(keytype));
4775 msgbuf = dupprintf("Unable to use key file \"%.150s\""
4776 " (%s)\r\n",
4777 filename_to_str(&ssh->cfg.keyfile),
4778 key_type_to_str(keytype));
4779 c_write_str(ssh, msgbuf);
4780 sfree(msgbuf);
4781 s->publickey_blob = NULL;
4782 }
4783 } else
4784 s->publickey_blob = NULL;
4785
4786 while (1) {
4787 /*
4788 * Wait for the result of the last authentication request.
4789 */
4790 if (!s->gotit)
4791 crWaitUntilV(ispkt);
4792 while (ssh->pktin.type == SSH2_MSG_USERAUTH_BANNER) {
4793 char *banner;
4794 int size;
4795 /*
4796 * Don't show the banner if we're operating in
4797 * non-verbose non-interactive mode. (It's probably
4798 * a script, which means nobody will read the
4799 * banner _anyway_, and moreover the printing of
4800 * the banner will screw up processing on the
4801 * output of (say) plink.)
4802 */
4803 if (flags & (FLAG_VERBOSE | FLAG_INTERACTIVE)) {
4804 ssh_pkt_getstring(ssh, &banner, &size);
4805 if (banner)
4806 c_write_untrusted(ssh, banner, size);
4807 }
4808 crWaitUntilV(ispkt);
4809 }
4810 if (ssh->pktin.type == SSH2_MSG_USERAUTH_SUCCESS) {
4811 logevent("Access granted");
4812 s->we_are_in = TRUE;
4813 break;
4814 }
4815
4816 if (s->kbd_inter_running &&
4817 ssh->pktin.type == SSH2_MSG_USERAUTH_INFO_REQUEST) {
4818 /*
4819 * This is either a further set-of-prompts packet
4820 * in keyboard-interactive authentication, or it's
4821 * the same one and we came back here with `gotit'
4822 * set. In the former case, we must reset the
4823 * curr_prompt variable.
4824 */
4825 if (!s->gotit)
4826 s->curr_prompt = 0;
4827 } else if (ssh->pktin.type != SSH2_MSG_USERAUTH_FAILURE) {
4828 bombout(("Strange packet received during authentication: type %d",
4829 ssh->pktin.type));
4830 crStopV;
4831 }
4832
4833 s->gotit = FALSE;
4834
4835 /*
4836 * OK, we're now sitting on a USERAUTH_FAILURE message, so
4837 * we can look at the string in it and know what we can
4838 * helpfully try next.
4839 */
4840 if (ssh->pktin.type == SSH2_MSG_USERAUTH_FAILURE) {
4841 char *methods;
4842 int methlen;
4843 ssh_pkt_getstring(ssh, &methods, &methlen);
4844 s->kbd_inter_running = FALSE;
4845 if (!ssh2_pkt_getbool(ssh)) {
4846 /*
4847 * We have received an unequivocal Access
4848 * Denied. This can translate to a variety of
4849 * messages:
4850 *
4851 * - if we'd just tried "none" authentication,
4852 * it's not worth printing anything at all
4853 *
4854 * - if we'd just tried a public key _offer_,
4855 * the message should be "Server refused our
4856 * key" (or no message at all if the key
4857 * came from Pageant)
4858 *
4859 * - if we'd just tried anything else, the
4860 * message really should be "Access denied".
4861 *
4862 * Additionally, if we'd just tried password
4863 * authentication, we should break out of this
4864 * whole loop so as to go back to the username
4865 * prompt.
4866 */
4867 if (s->type == AUTH_TYPE_NONE) {
4868 /* do nothing */
4869 } else if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD ||
4870 s->type == AUTH_TYPE_PUBLICKEY_OFFER_QUIET) {
4871 if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD)
4872 c_write_str(ssh, "Server refused our key\r\n");
4873 logevent("Server refused public key");
4874 } else if (s->type==AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET) {
4875 /* server declined keyboard-interactive; ignore */
4876 } else {
4877 c_write_str(ssh, "Access denied\r\n");
4878 logevent("Access denied");
4879 if (s->type == AUTH_TYPE_PASSWORD) {
4880 s->we_are_in = FALSE;
4881 break;
4882 }
4883 }
4884 } else {
4885 c_write_str(ssh, "Further authentication required\r\n");
4886 logevent("Further authentication required");
4887 }
4888
4889 s->can_pubkey =
4890 in_commasep_string("publickey", methods, methlen);
4891 s->can_passwd =
4892 in_commasep_string("password", methods, methlen);
4893 s->can_keyb_inter = ssh->cfg.try_ki_auth &&
4894 in_commasep_string("keyboard-interactive", methods, methlen);
4895 }
4896
4897 s->method = 0;
4898 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4899 s->need_pw = FALSE;
4900
4901 /*
4902 * Most password/passphrase prompts will be
4903 * non-echoing, so we set this to 0 by default.
4904 * Exception is that some keyboard-interactive prompts
4905 * can be echoing, in which case we'll set this to 1.
4906 */
4907 s->echo = 0;
4908
4909 if (!s->method && s->can_pubkey &&
4910 agent_exists() && !s->tried_agent) {
4911 /*
4912 * Attempt public-key authentication using Pageant.
4913 */
4914 void *r;
4915 s->authed = FALSE;
4916
4917 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4918 ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
4919
4920 s->tried_agent = TRUE;
4921
4922 logevent("Pageant is running. Requesting keys.");
4923
4924 /* Request the keys held by the agent. */
4925 PUT_32BIT(s->request, 1);
4926 s->request[4] = SSH2_AGENTC_REQUEST_IDENTITIES;
4927 if (!agent_query(s->request, 5, &r, &s->responselen,
4928 ssh_agent_callback, ssh)) {
4929 do {
4930 crReturnV;
4931 if (ispkt) {
4932 bombout(("Unexpected data from server while"
4933 " waiting for agent response"));
4934 crStopV;
4935 }
4936 } while (ispkt || inlen > 0);
4937 r = ssh->agent_response;
4938 s->responselen = ssh->agent_response_len;
4939 }
4940 s->response = (unsigned char *) r;
4941 if (s->response && s->responselen >= 5 &&
4942 s->response[4] == SSH2_AGENT_IDENTITIES_ANSWER) {
4943 s->p = s->response + 5;
4944 s->nkeys = GET_32BIT(s->p);
4945 s->p += 4;
4946 {
4947 char buf[64];
4948 sprintf(buf, "Pageant has %d SSH2 keys", s->nkeys);
4949 logevent(buf);
4950 }
4951 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
4952 void *vret;
4953
4954 {
4955 char buf[64];
4956 sprintf(buf, "Trying Pageant key #%d", s->keyi);
4957 logevent(buf);
4958 }
4959 s->pklen = GET_32BIT(s->p);
4960 s->p += 4;
4961 if (s->publickey_blob &&
4962 s->pklen == s->publickey_bloblen &&
4963 !memcmp(s->p, s->publickey_blob,
4964 s->publickey_bloblen)) {
4965 logevent("This key matches configured key file");
4966 s->tried_pubkey_config = 1;
4967 }
4968 s->pkblob = (char *)s->p;
4969 s->p += s->pklen;
4970 s->alglen = GET_32BIT(s->pkblob);
4971 s->alg = s->pkblob + 4;
4972 s->commentlen = GET_32BIT(s->p);
4973 s->p += 4;
4974 s->commentp = (char *)s->p;
4975 s->p += s->commentlen;
4976 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4977 ssh2_pkt_addstring(ssh, s->username);
4978 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4979 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4980 ssh2_pkt_addbool(ssh, FALSE); /* no signature included */
4981 ssh2_pkt_addstring_start(ssh);
4982 ssh2_pkt_addstring_data(ssh, s->alg, s->alglen);
4983 ssh2_pkt_addstring_start(ssh);
4984 ssh2_pkt_addstring_data(ssh, s->pkblob, s->pklen);
4985 ssh2_pkt_send(ssh);
4986
4987 crWaitUntilV(ispkt);
4988 if (ssh->pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
4989 logevent("Key refused");
4990 continue;
4991 }
4992
4993 if (flags & FLAG_VERBOSE) {
4994 c_write_str(ssh, "Authenticating with "
4995 "public key \"");
4996 c_write(ssh, s->commentp, s->commentlen);
4997 c_write_str(ssh, "\" from agent\r\n");
4998 }
4999
5000 /*
5001 * Server is willing to accept the key.
5002 * Construct a SIGN_REQUEST.
5003 */
5004 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
5005 ssh2_pkt_addstring(ssh, s->username);
5006 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
5007 ssh2_pkt_addstring(ssh, "publickey"); /* method */
5008 ssh2_pkt_addbool(ssh, TRUE);
5009 ssh2_pkt_addstring_start(ssh);
5010 ssh2_pkt_addstring_data(ssh, s->alg, s->alglen);
5011 ssh2_pkt_addstring_start(ssh);
5012 ssh2_pkt_addstring_data(ssh, s->pkblob, s->pklen);
5013
5014 s->siglen = ssh->pktout.length - 5 + 4 + 20;
5015 if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
5016 s->siglen -= 4;
5017 s->len = 1; /* message type */
5018 s->len += 4 + s->pklen; /* key blob */
5019 s->len += 4 + s->siglen; /* data to sign */
5020 s->len += 4; /* flags */
5021 s->agentreq = snewn(4 + s->len, char);
5022 PUT_32BIT(s->agentreq, s->len);
5023 s->q = s->agentreq + 4;
5024 *s->q++ = SSH2_AGENTC_SIGN_REQUEST;
5025 PUT_32BIT(s->q, s->pklen);
5026 s->q += 4;
5027 memcpy(s->q, s->pkblob, s->pklen);
5028 s->q += s->pklen;
5029 PUT_32BIT(s->q, s->siglen);
5030 s->q += 4;
5031 /* Now the data to be signed... */
5032 if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
5033 PUT_32BIT(s->q, 20);
5034 s->q += 4;
5035 }
5036 memcpy(s->q, ssh->v2_session_id, 20);
5037 s->q += 20;
5038 memcpy(s->q, ssh->pktout.data + 5,
5039 ssh->pktout.length - 5);
5040 s->q += ssh->pktout.length - 5;
5041 /* And finally the (zero) flags word. */
5042 PUT_32BIT(s->q, 0);
5043 if (!agent_query(s->agentreq, s->len + 4,
5044 &vret, &s->retlen,
5045 ssh_agent_callback, ssh)) {
5046 do {
5047 crReturnV;
5048 if (ispkt) {
5049 bombout(("Unexpected data from server"
5050 " while waiting for agent"
5051 " response"));
5052 crStopV;
5053 }
5054 } while (ispkt || inlen > 0);
5055 vret = ssh->agent_response;
5056 s->retlen = ssh->agent_response_len;
5057 }
5058 s->ret = vret;
5059 sfree(s->agentreq);
5060 if (s->ret) {
5061 if (s->ret[4] == SSH2_AGENT_SIGN_RESPONSE) {
5062 logevent("Sending Pageant's response");
5063 ssh2_add_sigblob(ssh, s->pkblob, s->pklen,
5064 s->ret + 9,
5065 GET_32BIT(s->ret + 5));
5066 ssh2_pkt_send(ssh);
5067 s->authed = TRUE;
5068 break;
5069 } else {
5070 logevent
5071 ("Pageant failed to answer challenge");
5072 sfree(s->ret);
5073 }
5074 }
5075 }
5076 if (s->authed)
5077 continue;
5078 }
5079 sfree(s->response);
5080 }
5081
5082 if (!s->method && s->can_pubkey && s->publickey_blob
5083 && !s->tried_pubkey_config) {
5084 unsigned char *pub_blob;
5085 char *algorithm, *comment;
5086 int pub_blob_len;
5087
5088 s->tried_pubkey_config = TRUE;
5089
5090 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
5091 ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
5092
5093 /*
5094 * Try the public key supplied in the configuration.
5095 *
5096 * First, offer the public blob to see if the server is
5097 * willing to accept it.
5098 */
5099 pub_blob =
5100 (unsigned char *)ssh2_userkey_loadpub(&ssh->cfg.keyfile,
5101 &algorithm,
5102 &pub_blob_len,
5103 NULL);
5104 if (pub_blob) {
5105 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
5106 ssh2_pkt_addstring(ssh, s->username);
5107 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
5108 ssh2_pkt_addstring(ssh, "publickey"); /* method */
5109 ssh2_pkt_addbool(ssh, FALSE); /* no signature included */
5110 ssh2_pkt_addstring(ssh, algorithm);
5111 ssh2_pkt_addstring_start(ssh);
5112 ssh2_pkt_addstring_data(ssh, (char *)pub_blob,
5113 pub_blob_len);
5114 ssh2_pkt_send(ssh);
5115 logevent("Offered public key"); /* FIXME */
5116
5117 crWaitUntilV(ispkt);
5118 if (ssh->pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
5119 s->gotit = TRUE;
5120 s->type = AUTH_TYPE_PUBLICKEY_OFFER_LOUD;
5121 continue; /* key refused; give up on it */
5122 }
5123
5124 logevent("Offer of public key accepted");
5125 /*
5126 * Actually attempt a serious authentication using
5127 * the key.
5128 */
5129 if (ssh2_userkey_encrypted(&ssh->cfg.keyfile, &comment)) {
5130 sprintf(s->pwprompt,
5131 "Passphrase for key \"%.100s\": ",
5132 comment);
5133 s->need_pw = TRUE;
5134 } else {
5135 s->need_pw = FALSE;
5136 }
5137 if (flags & FLAG_VERBOSE) {
5138 c_write_str(ssh, "Authenticating with public key \"");
5139 c_write_str(ssh, comment);
5140 c_write_str(ssh, "\"\r\n");
5141 }
5142 s->method = AUTH_PUBLICKEY_FILE;
5143 }
5144 }
5145
5146 if (!s->method && s->can_keyb_inter && !s->tried_keyb_inter) {
5147 s->method = AUTH_KEYBOARD_INTERACTIVE;
5148 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
5149 s->tried_keyb_inter = TRUE;
5150
5151 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
5152 ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;
5153
5154 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
5155 ssh2_pkt_addstring(ssh, s->username);
5156 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
5157 ssh2_pkt_addstring(ssh, "keyboard-interactive"); /* method */
5158 ssh2_pkt_addstring(ssh, ""); /* lang */
5159 ssh2_pkt_addstring(ssh, "");
5160 ssh2_pkt_send(ssh);
5161
5162 crWaitUntilV(ispkt);
5163 if (ssh->pktin.type != SSH2_MSG_USERAUTH_INFO_REQUEST) {
5164 if (ssh->pktin.type == SSH2_MSG_USERAUTH_FAILURE)
5165 s->gotit = TRUE;
5166 logevent("Keyboard-interactive authentication refused");
5167 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET;
5168 continue;
5169 }
5170
5171 s->kbd_inter_running = TRUE;
5172 s->curr_prompt = 0;
5173 }
5174
5175 if (s->kbd_inter_running) {
5176 s->method = AUTH_KEYBOARD_INTERACTIVE;
5177 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
5178 s->tried_keyb_inter = TRUE;
5179
5180 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
5181 ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;
5182
5183 if (s->curr_prompt == 0) {
5184 /*
5185 * We've got a fresh USERAUTH_INFO_REQUEST.
5186 * Display header data, and start going through
5187 * the prompts.
5188 */
5189 char *name, *inst, *lang;
5190 int name_len, inst_len, lang_len;
5191
5192 ssh_pkt_getstring(ssh, &name, &name_len);
5193 ssh_pkt_getstring(ssh, &inst, &inst_len);
5194 ssh_pkt_getstring(ssh, &lang, &lang_len);
5195 if (name_len > 0) {
5196 c_write_untrusted(ssh, name, name_len);
5197 c_write_str(ssh, "\r\n");
5198 }
5199 if (inst_len > 0) {
5200 c_write_untrusted(ssh, inst, inst_len);
5201 c_write_str(ssh, "\r\n");
5202 }
5203 s->num_prompts = ssh_pkt_getuint32(ssh);
5204 }
5205
5206 /*
5207 * If there are prompts remaining in the packet,
5208 * display one and get a response.
5209 */
5210 if (s->curr_prompt < s->num_prompts) {
5211 char *prompt;
5212 int prompt_len;
5213
5214 ssh_pkt_getstring(ssh, &prompt, &prompt_len);
5215 if (prompt_len > 0) {
5216 static const char trunc[] = "<prompt truncated>: ";
5217 static const int prlen = sizeof(s->pwprompt) -
5218 lenof(trunc);
5219 if (prompt_len > prlen) {
5220 memcpy(s->pwprompt, prompt, prlen);
5221 strcpy(s->pwprompt + prlen, trunc);
5222 } else {
5223 memcpy(s->pwprompt, prompt, prompt_len);
5224 s->pwprompt[prompt_len] = '\0';
5225 }
5226 } else {
5227 strcpy(s->pwprompt,
5228 "<server failed to send prompt>: ");
5229 }
5230 s->echo = ssh2_pkt_getbool(ssh);
5231 s->need_pw = TRUE;
5232 } else
5233 s->need_pw = FALSE;
5234 }
5235
5236 if (!s->method && s->can_passwd) {
5237 s->method = AUTH_PASSWORD;
5238 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
5239 ssh->pkt_ctx |= SSH2_PKTCTX_PASSWORD;
5240 sprintf(s->pwprompt, "%.90s@%.90s's password: ", s->username,
5241 ssh->savedhost);
5242 s->need_pw = TRUE;
5243 }
5244
5245 if (s->need_pw) {
5246 if (ssh_get_line) {
5247 if (!ssh_get_line(s->pwprompt, s->password,
5248 sizeof(s->password), TRUE)) {
5249 /*
5250 * get_line failed to get a password (for
5251 * example because one was supplied on the
5252 * command line which has already failed to
5253 * work). Terminate.
5254 */
5255 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5256 ssh2_pkt_adduint32(ssh,SSH2_DISCONNECT_BY_APPLICATION);
5257 ssh2_pkt_addstring(ssh, "No more passwords available"
5258 " to try");
5259 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5260 ssh2_pkt_send(ssh);
5261 logevent("Unable to authenticate");
5262 connection_fatal(ssh->frontend,
5263 "Unable to authenticate");
5264 ssh_closing((Plug)ssh, NULL, 0, 0);
5265 crStopV;
5266 }
5267 } else {
5268 int ret; /* need not be saved across crReturn */
5269 c_write_untrusted(ssh, s->pwprompt, strlen(s->pwprompt));
5270 ssh->send_ok = 1;
5271
5272 setup_userpass_input(ssh, s->password,
5273 sizeof(s->password), s->echo);
5274 do {
5275 crWaitUntilV(!ispkt);
5276 ret = process_userpass_input(ssh, in, inlen);
5277 } while (ret == 0);
5278 if (ret < 0)
5279 cleanup_exit(0);
5280 c_write_str(ssh, "\r\n");
5281 }
5282 }
5283
5284 if (s->method == AUTH_PUBLICKEY_FILE) {
5285 /*
5286 * We have our passphrase. Now try the actual authentication.
5287 */
5288 struct ssh2_userkey *key;
5289 const char *error = NULL;
5290
5291 key = ssh2_load_userkey(&ssh->cfg.keyfile, s->password,
5292 &error);
5293 if (key == SSH2_WRONG_PASSPHRASE || key == NULL) {
5294 if (key == SSH2_WRONG_PASSPHRASE) {
5295 c_write_str(ssh, "Wrong passphrase\r\n");
5296 s->tried_pubkey_config = FALSE;
5297 } else {
5298 c_write_str(ssh, "Unable to load private key (");
5299 c_write_str(ssh, error);
5300 c_write_str(ssh, ")\r\n");
5301 s->tried_pubkey_config = TRUE;
5302 }
5303 /* Send a spurious AUTH_NONE to return to the top. */
5304 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
5305 ssh2_pkt_addstring(ssh, s->username);
5306 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
5307 ssh2_pkt_addstring(ssh, "none"); /* method */
5308 ssh2_pkt_send(ssh);
5309 s->type = AUTH_TYPE_NONE;
5310 } else {
5311 unsigned char *pkblob, *sigblob, *sigdata;
5312 int pkblob_len, sigblob_len, sigdata_len;
5313 int p;
5314
5315 /*
5316 * We have loaded the private key and the server
5317 * has announced that it's willing to accept it.
5318 * Hallelujah. Generate a signature and send it.
5319 */
5320 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
5321 ssh2_pkt_addstring(ssh, s->username);
5322 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
5323 ssh2_pkt_addstring(ssh, "publickey"); /* method */
5324 ssh2_pkt_addbool(ssh, TRUE);
5325 ssh2_pkt_addstring(ssh, key->alg->name);
5326 pkblob = key->alg->public_blob(key->data, &pkblob_len);
5327 ssh2_pkt_addstring_start(ssh);
5328 ssh2_pkt_addstring_data(ssh, (char *)pkblob, pkblob_len);
5329
5330 /*
5331 * The data to be signed is:
5332 *
5333 * string session-id
5334 *
5335 * followed by everything so far placed in the
5336 * outgoing packet.
5337 */
5338 sigdata_len = ssh->pktout.length - 5 + 4 + 20;
5339 if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
5340 sigdata_len -= 4;
5341 sigdata = snewn(sigdata_len, unsigned char);
5342 p = 0;
5343 if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
5344 PUT_32BIT(sigdata+p, 20);
5345 p += 4;
5346 }
5347 memcpy(sigdata+p, ssh->v2_session_id, 20); p += 20;
5348 memcpy(sigdata+p, ssh->pktout.data + 5,
5349 ssh->pktout.length - 5);
5350 p += ssh->pktout.length - 5;
5351 assert(p == sigdata_len);
5352 sigblob = key->alg->sign(key->data, (char *)sigdata,
5353 sigdata_len, &sigblob_len);
5354 ssh2_add_sigblob(ssh, pkblob, pkblob_len,
5355 sigblob, sigblob_len);
5356 sfree(pkblob);
5357 sfree(sigblob);
5358 sfree(sigdata);
5359
5360 ssh2_pkt_send(ssh);
5361 s->type = AUTH_TYPE_PUBLICKEY;
5362 key->alg->freekey(key->data);
5363 }
5364 } else if (s->method == AUTH_PASSWORD) {
5365 /*
5366 * We send the password packet lumped tightly together with
5367 * an SSH_MSG_IGNORE packet. The IGNORE packet contains a
5368 * string long enough to make the total length of the two
5369 * packets constant. This should ensure that a passive
5370 * listener doing traffic analyis can't work out the length
5371 * of the password.
5372 *
5373 * For this to work, we need an assumption about the
5374 * maximum length of the password packet. I think 256 is
5375 * pretty conservative. Anyone using a password longer than
5376 * that probably doesn't have much to worry about from
5377 * people who find out how long their password is!
5378 */
5379 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
5380 ssh2_pkt_addstring(ssh, s->username);
5381 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
5382 ssh2_pkt_addstring(ssh, "password");
5383 ssh2_pkt_addbool(ssh, FALSE);
5384 ssh2_pkt_addstring(ssh, s->password);
5385 memset(s->password, 0, sizeof(s->password));
5386 ssh2_pkt_defer(ssh);
5387 /*
5388 * We'll include a string that's an exact multiple of the
5389 * cipher block size. If the cipher is NULL for some
5390 * reason, we don't do this trick at all because we gain
5391 * nothing by it.
5392 */
5393 if (ssh->cscipher) {
5394 int stringlen, i;
5395
5396 stringlen = (256 - ssh->deferred_len);
5397 stringlen += ssh->cscipher->blksize - 1;
5398 stringlen -= (stringlen % ssh->cscipher->blksize);
5399 if (ssh->cscomp) {
5400 /*
5401 * Temporarily disable actual compression,
5402 * so we can guarantee to get this string
5403 * exactly the length we want it. The
5404 * compression-disabling routine should
5405 * return an integer indicating how many
5406 * bytes we should adjust our string length
5407 * by.
5408 */
5409 stringlen -=
5410 ssh->cscomp->disable_compression(ssh->cs_comp_ctx);
5411 }
5412 ssh2_pkt_init(ssh, SSH2_MSG_IGNORE);
5413 ssh2_pkt_addstring_start(ssh);
5414 for (i = 0; i < stringlen; i++) {
5415 char c = (char) random_byte();
5416 ssh2_pkt_addstring_data(ssh, &c, 1);
5417 }
5418 ssh2_pkt_defer(ssh);
5419 }
5420 ssh_pkt_defersend(ssh);
5421 logevent("Sent password");
5422 s->type = AUTH_TYPE_PASSWORD;
5423 } else if (s->method == AUTH_KEYBOARD_INTERACTIVE) {
5424 if (s->curr_prompt == 0) {
5425 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_INFO_RESPONSE);
5426 ssh2_pkt_adduint32(ssh, s->num_prompts);
5427 }
5428 if (s->need_pw) { /* only add pw if we just got one! */
5429 ssh2_pkt_addstring(ssh, s->password);
5430 memset(s->password, 0, sizeof(s->password));
5431 s->curr_prompt++;
5432 }
5433 if (s->curr_prompt >= s->num_prompts) {
5434 ssh2_pkt_send(ssh);
5435 } else {
5436 /*
5437 * If there are prompts remaining, we set
5438 * `gotit' so that we won't attempt to get
5439 * another packet. Then we go back round the
5440 * loop and will end up retrieving another
5441 * prompt out of the existing packet. Funky or
5442 * what?
5443 */
5444 s->gotit = TRUE;
5445 }
5446 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
5447 } else {
5448 c_write_str(ssh, "No supported authentication methods"
5449 " left to try!\r\n");
5450 logevent("No supported authentications offered."
5451 " Disconnecting");
5452 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5453 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5454 ssh2_pkt_addstring(ssh, "No supported authentication"
5455 " methods available");
5456 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5457 ssh2_pkt_send(ssh);
5458 ssh_closing((Plug)ssh, NULL, 0, 0);
5459 crStopV;
5460 }
5461 }
5462 } while (!s->we_are_in);
5463
5464 /*
5465 * Now we're authenticated for the connection protocol. The
5466 * connection protocol will automatically have started at this
5467 * point; there's no need to send SERVICE_REQUEST.
5468 */
5469
5470 /*
5471 * So now create a channel with a session in it.
5472 */
5473 ssh->channels = newtree234(ssh_channelcmp);
5474 ssh->mainchan = snew(struct ssh_channel);
5475 ssh->mainchan->ssh = ssh;
5476 ssh->mainchan->localid = alloc_channel_id(ssh);
5477 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN);
5478 ssh2_pkt_addstring(ssh, "session");
5479 ssh2_pkt_adduint32(ssh, ssh->mainchan->localid);
5480 ssh->mainchan->v.v2.locwindow = OUR_V2_WINSIZE;
5481 ssh2_pkt_adduint32(ssh, ssh->mainchan->v.v2.locwindow);/* our window size */
5482 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
5483 ssh2_pkt_send(ssh);
5484 crWaitUntilV(ispkt);
5485 if (ssh->pktin.type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
5486 bombout(("Server refused to open a session"));
5487 crStopV;
5488 /* FIXME: error data comes back in FAILURE packet */
5489 }
5490 if (ssh_pkt_getuint32(ssh) != ssh->mainchan->localid) {
5491 bombout(("Server's channel confirmation cited wrong channel"));
5492 crStopV;
5493 }
5494 ssh->mainchan->remoteid = ssh_pkt_getuint32(ssh);
5495 ssh->mainchan->type = CHAN_MAINSESSION;
5496 ssh->mainchan->closes = 0;
5497 ssh->mainchan->v.v2.remwindow = ssh_pkt_getuint32(ssh);
5498 ssh->mainchan->v.v2.remmaxpkt = ssh_pkt_getuint32(ssh);
5499 bufchain_init(&ssh->mainchan->v.v2.outbuffer);
5500 add234(ssh->channels, ssh->mainchan);
5501 logevent("Opened channel for session");
5502
5503 /*
5504 * Potentially enable X11 forwarding.
5505 */
5506 if (ssh->cfg.x11_forward) {
5507 char proto[20], data[64];
5508 logevent("Requesting X11 forwarding");
5509 ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
5510 data, sizeof(data), ssh->cfg.x11_auth);
5511 x11_get_real_auth(ssh->x11auth, ssh->cfg.x11_display);
5512 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5513 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
5514 ssh2_pkt_addstring(ssh, "x11-req");
5515 ssh2_pkt_addbool(ssh, 1); /* want reply */
5516 ssh2_pkt_addbool(ssh, 0); /* many connections */
5517 ssh2_pkt_addstring(ssh, proto);
5518 ssh2_pkt_addstring(ssh, data);
5519 ssh2_pkt_adduint32(ssh, x11_get_screen_number(ssh->cfg.x11_display));
5520 ssh2_pkt_send(ssh);
5521
5522 do {
5523 crWaitUntilV(ispkt);
5524 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5525 unsigned i = ssh_pkt_getuint32(ssh);
5526 struct ssh_channel *c;
5527 c = find234(ssh->channels, &i, ssh_channelfind);
5528 if (!c)
5529 continue; /* nonexistent channel */
5530 c->v.v2.remwindow += ssh_pkt_getuint32(ssh);
5531 }
5532 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5533
5534 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5535 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5536 bombout(("Unexpected response to X11 forwarding request:"
5537 " packet type %d", ssh->pktin.type));
5538 crStopV;
5539 }
5540 logevent("X11 forwarding refused");
5541 } else {
5542 logevent("X11 forwarding enabled");
5543 ssh->X11_fwd_enabled = TRUE;
5544 }
5545 }
5546
5547 /*
5548 * Enable port forwardings.
5549 */
5550 {
5551 char type;
5552 int n;
5553 int sport,dport,sserv,dserv;
5554 char sports[256], dports[256], saddr[256], host[256];
5555
5556 ssh->rportfwds = newtree234(ssh_rportcmp_ssh2);
5557 /* Add port forwardings. */
5558 ssh->portfwd_strptr = ssh->cfg.portfwd;
5559 while (*ssh->portfwd_strptr) {
5560 type = *ssh->portfwd_strptr++;
5561 saddr[0] = '\0';
5562 n = 0;
5563 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != '\t') {
5564 if (*ssh->portfwd_strptr == ':') {
5565 /*
5566 * We've seen a colon in the middle of the
5567 * source port number. This means that
5568 * everything we've seen until now is the
5569 * source _address_, so we'll move it into
5570 * saddr and start sports from the beginning
5571 * again.
5572 */
5573 ssh->portfwd_strptr++;
5574 sports[n] = '\0';
5575 strcpy(saddr, sports);
5576 n = 0;
5577 }
5578 if (n < 255) sports[n++] = *ssh->portfwd_strptr++;
5579 }
5580 sports[n] = 0;
5581 if (type != 'D') {
5582 if (*ssh->portfwd_strptr == '\t')
5583 ssh->portfwd_strptr++;
5584 n = 0;
5585 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':') {
5586 if (n < 255) host[n++] = *ssh->portfwd_strptr++;
5587 }
5588 host[n] = 0;
5589 if (*ssh->portfwd_strptr == ':')
5590 ssh->portfwd_strptr++;
5591 n = 0;
5592 while (*ssh->portfwd_strptr) {
5593 if (n < 255) dports[n++] = *ssh->portfwd_strptr++;
5594 }
5595 dports[n] = 0;
5596 ssh->portfwd_strptr++;
5597 dport = atoi(dports);
5598 dserv = 0;
5599 if (dport == 0) {
5600 dserv = 1;
5601 dport = net_service_lookup(dports);
5602 if (!dport) {
5603 logeventf(ssh, "Service lookup failed for destination"
5604 " port \"%s\"", dports);
5605 }
5606 }
5607 } else {
5608 while (*ssh->portfwd_strptr) ssh->portfwd_strptr++;
5609 dport = dserv = -1;
5610 ssh->portfwd_strptr++; /* eat the NUL and move to next one */
5611 }
5612 sport = atoi(sports);
5613 sserv = 0;
5614 if (sport == 0) {
5615 sserv = 1;
5616 sport = net_service_lookup(sports);
5617 if (!sport) {
5618 logeventf(ssh, "Service lookup failed for source"
5619 " port \"%s\"", sports);
5620 }
5621 }
5622 if (sport && dport) {
5623 /* Set up a description of the source port. */
5624 char *sportdesc = dupprintf("%.*s%.*s%.*s%.*s%d%.*s",
5625 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
5626 (int)(*saddr?1:0), ":",
5627 (int)(sserv ? strlen(sports) : 0), sports,
5628 sserv, "(", sport, sserv, ")");
5629 if (type == 'L') {
5630 /* Verbose description of the destination port */
5631 char *dportdesc = dupprintf("%s:%.*s%.*s%d%.*s",
5632 host,
5633 (int)(dserv ? strlen(dports) : 0), dports,
5634 dserv, "(", dport, dserv, ")");
5635 const char *err = pfd_addforward(host, dport,
5636 *saddr ? saddr : NULL,
5637 sport, ssh, &ssh->cfg);
5638 if (err) {
5639 logeventf(ssh, "Local port %s forward to %s"
5640 " failed: %s", sportdesc, dportdesc, err);
5641 } else {
5642 logeventf(ssh, "Local port %s forwarding to %s",
5643 sportdesc, dportdesc);
5644 }
5645 sfree(dportdesc);
5646 } else if (type == 'D') {
5647 const char *err = pfd_addforward(NULL, -1,
5648 *saddr ? saddr : NULL,
5649 sport, ssh, &ssh->cfg);
5650 if (err) {
5651 logeventf(ssh, "Local port %s SOCKS dynamic forward"
5652 " setup failed: %s", sportdesc, err);
5653 } else {
5654 logeventf(ssh, "Local port %s doing SOCKS"
5655 " dynamic forwarding", sportdesc);
5656 }
5657 } else {
5658 struct ssh_rportfwd *pf;
5659 pf = snew(struct ssh_rportfwd);
5660 strcpy(pf->dhost, host);
5661 pf->dport = dport;
5662 pf->sport = sport;
5663 if (add234(ssh->rportfwds, pf) != pf) {
5664 logeventf(ssh, "Duplicate remote port forwarding"
5665 " to %s:%d", host, dport);
5666 sfree(pf);
5667 } else {
5668 logeventf(ssh, "Requesting remote port %s"
5669 " forward to %s:%.*s%.*s%d%.*s",
5670 sportdesc,
5671 host,
5672 (int)(dserv ? strlen(dports) : 0), dports,
5673 dserv, "(", dport, dserv, ")");
5674 ssh2_pkt_init(ssh, SSH2_MSG_GLOBAL_REQUEST);
5675 ssh2_pkt_addstring(ssh, "tcpip-forward");
5676 ssh2_pkt_addbool(ssh, 1);/* want reply */
5677 if (*saddr)
5678 ssh2_pkt_addstring(ssh, saddr);
5679 if (ssh->cfg.rport_acceptall)
5680 ssh2_pkt_addstring(ssh, "0.0.0.0");
5681 else
5682 ssh2_pkt_addstring(ssh, "127.0.0.1");
5683 ssh2_pkt_adduint32(ssh, sport);
5684 ssh2_pkt_send(ssh);
5685
5686 do {
5687 crWaitUntilV(ispkt);
5688 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5689 unsigned i = ssh_pkt_getuint32(ssh);
5690 struct ssh_channel *c;
5691 c = find234(ssh->channels, &i, ssh_channelfind);
5692 if (!c)
5693 continue;/* nonexistent channel */
5694 c->v.v2.remwindow += ssh_pkt_getuint32(ssh);
5695 }
5696 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5697
5698 if (ssh->pktin.type != SSH2_MSG_REQUEST_SUCCESS) {
5699 if (ssh->pktin.type != SSH2_MSG_REQUEST_FAILURE) {
5700 bombout(("Unexpected response to port "
5701 "forwarding request: packet type %d",
5702 ssh->pktin.type));
5703 crStopV;
5704 }
5705 logevent("Server refused this port forwarding");
5706 } else {
5707 logevent("Remote port forwarding enabled");
5708 }
5709 }
5710 }
5711 sfree(sportdesc);
5712 }
5713 }
5714 }
5715
5716 /*
5717 * Potentially enable agent forwarding.
5718 */
5719 if (ssh->cfg.agentfwd && agent_exists()) {
5720 logevent("Requesting OpenSSH-style agent forwarding");
5721 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5722 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
5723 ssh2_pkt_addstring(ssh, "auth-agent-req@openssh.com");
5724 ssh2_pkt_addbool(ssh, 1); /* want reply */
5725 ssh2_pkt_send(ssh);
5726
5727 do {
5728 crWaitUntilV(ispkt);
5729 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5730 unsigned i = ssh_pkt_getuint32(ssh);
5731 struct ssh_channel *c;
5732 c = find234(ssh->channels, &i, ssh_channelfind);
5733 if (!c)
5734 continue; /* nonexistent channel */
5735 c->v.v2.remwindow += ssh_pkt_getuint32(ssh);
5736 }
5737 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5738
5739 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5740 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5741 bombout(("Unexpected response to agent forwarding request:"
5742 " packet type %d", ssh->pktin.type));
5743 crStopV;
5744 }
5745 logevent("Agent forwarding refused");
5746 } else {
5747 logevent("Agent forwarding enabled");
5748 ssh->agentfwd_enabled = TRUE;
5749 }
5750 }
5751
5752 /*
5753 * Now allocate a pty for the session.
5754 */
5755 if (!ssh->cfg.nopty) {
5756 /* Unpick the terminal-speed string. */
5757 /* XXX perhaps we should allow no speeds to be sent. */
5758 ssh->ospeed = 38400; ssh->ispeed = 38400; /* last-resort defaults */
5759 sscanf(ssh->cfg.termspeed, "%d,%d", &ssh->ospeed, &ssh->ispeed);
5760 /* Build the pty request. */
5761 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5762 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid); /* recipient channel */
5763 ssh2_pkt_addstring(ssh, "pty-req");
5764 ssh2_pkt_addbool(ssh, 1); /* want reply */
5765 ssh2_pkt_addstring(ssh, ssh->cfg.termtype);
5766 ssh2_pkt_adduint32(ssh, ssh->term_width);
5767 ssh2_pkt_adduint32(ssh, ssh->term_height);
5768 ssh2_pkt_adduint32(ssh, 0); /* pixel width */
5769 ssh2_pkt_adduint32(ssh, 0); /* pixel height */
5770 ssh2_pkt_addstring_start(ssh);
5771 ssh2_pkt_addbyte(ssh, 128); /* TTY_OP_ISPEED */
5772 ssh2_pkt_adduint32(ssh, ssh->ispeed);
5773 ssh2_pkt_addbyte(ssh, 129); /* TTY_OP_OSPEED */
5774 ssh2_pkt_adduint32(ssh, ssh->ospeed);
5775 ssh2_pkt_addstring_data(ssh, "\0", 1); /* TTY_OP_END */
5776 ssh2_pkt_send(ssh);
5777 ssh->state = SSH_STATE_INTERMED;
5778
5779 do {
5780 crWaitUntilV(ispkt);
5781 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5782 unsigned i = ssh_pkt_getuint32(ssh);
5783 struct ssh_channel *c;
5784 c = find234(ssh->channels, &i, ssh_channelfind);
5785 if (!c)
5786 continue; /* nonexistent channel */
5787 c->v.v2.remwindow += ssh_pkt_getuint32(ssh);
5788 }
5789 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5790
5791 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5792 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5793 bombout(("Unexpected response to pty request:"
5794 " packet type %d", ssh->pktin.type));
5795 crStopV;
5796 }
5797 c_write_str(ssh, "Server refused to allocate pty\r\n");
5798 ssh->editing = ssh->echoing = 1;
5799 } else {
5800 logeventf(ssh, "Allocated pty (ospeed %dbps, ispeed %dbps)",
5801 ssh->ospeed, ssh->ispeed);
5802 }
5803 } else {
5804 ssh->editing = ssh->echoing = 1;
5805 }
5806
5807 /*
5808 * Start a shell or a remote command. We may have to attempt
5809 * this twice if the config data has provided a second choice
5810 * of command.
5811 */
5812 while (1) {
5813 int subsys;
5814 char *cmd;
5815
5816 if (ssh->fallback_cmd) {
5817 subsys = ssh->cfg.ssh_subsys2;
5818 cmd = ssh->cfg.remote_cmd_ptr2;
5819 } else {
5820 subsys = ssh->cfg.ssh_subsys;
5821 cmd = ssh->cfg.remote_cmd_ptr;
5822 }
5823
5824 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5825 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid); /* recipient channel */
5826 if (subsys) {
5827 ssh2_pkt_addstring(ssh, "subsystem");
5828 ssh2_pkt_addbool(ssh, 1); /* want reply */
5829 ssh2_pkt_addstring(ssh, cmd);
5830 } else if (*cmd) {
5831 ssh2_pkt_addstring(ssh, "exec");
5832 ssh2_pkt_addbool(ssh, 1); /* want reply */
5833 ssh2_pkt_addstring(ssh, cmd);
5834 } else {
5835 ssh2_pkt_addstring(ssh, "shell");
5836 ssh2_pkt_addbool(ssh, 1); /* want reply */
5837 }
5838 ssh2_pkt_send(ssh);
5839 do {
5840 crWaitUntilV(ispkt);
5841 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5842 unsigned i = ssh_pkt_getuint32(ssh);
5843 struct ssh_channel *c;
5844 c = find234(ssh->channels, &i, ssh_channelfind);
5845 if (!c)
5846 continue; /* nonexistent channel */
5847 c->v.v2.remwindow += ssh_pkt_getuint32(ssh);
5848 }
5849 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5850 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5851 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5852 bombout(("Unexpected response to shell/command request:"
5853 " packet type %d", ssh->pktin.type));
5854 crStopV;
5855 }
5856 /*
5857 * We failed to start the command. If this is the
5858 * fallback command, we really are finished; if it's
5859 * not, and if the fallback command exists, try falling
5860 * back to it before complaining.
5861 */
5862 if (!ssh->fallback_cmd && ssh->cfg.remote_cmd_ptr2 != NULL) {
5863 logevent("Primary command failed; attempting fallback");
5864 ssh->fallback_cmd = TRUE;
5865 continue;
5866 }
5867 bombout(("Server refused to start a shell/command"));
5868 crStopV;
5869 } else {
5870 logevent("Started a shell/command");
5871 }
5872 break;
5873 }
5874
5875 ssh->state = SSH_STATE_SESSION;
5876 if (ssh->size_needed)
5877 ssh_size(ssh, ssh->term_width, ssh->term_height);
5878 if (ssh->eof_needed)
5879 ssh_special(ssh, TS_EOF);
5880
5881 /*
5882 * Transfer data!
5883 */
5884 if (ssh->ldisc)
5885 ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */
5886 ssh->send_ok = 1;
5887 while (1) {
5888 crReturnV;
5889 s->try_send = FALSE;
5890 if (ispkt) {
5891 if (ssh->pktin.type == SSH2_MSG_CHANNEL_DATA ||
5892 ssh->pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA) {
5893 char *data;
5894 int length;
5895 unsigned i = ssh_pkt_getuint32(ssh);
5896 struct ssh_channel *c;
5897 c = find234(ssh->channels, &i, ssh_channelfind);
5898 if (!c)
5899 continue; /* nonexistent channel */
5900 if (ssh->pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
5901 ssh_pkt_getuint32(ssh) != SSH2_EXTENDED_DATA_STDERR)
5902 continue; /* extended but not stderr */
5903 ssh_pkt_getstring(ssh, &data, &length);
5904 if (data) {
5905 int bufsize = 0;
5906 c->v.v2.locwindow -= length;
5907 switch (c->type) {
5908 case CHAN_MAINSESSION:
5909 bufsize =
5910 from_backend(ssh->frontend, ssh->pktin.type ==
5911 SSH2_MSG_CHANNEL_EXTENDED_DATA,
5912 data, length);
5913 break;
5914 case CHAN_X11:
5915 bufsize = x11_send(c->u.x11.s, data, length);
5916 break;
5917 case CHAN_SOCKDATA:
5918 bufsize = pfd_send(c->u.pfd.s, data, length);
5919 break;
5920 case CHAN_AGENT:
5921 while (length > 0) {
5922 if (c->u.a.lensofar < 4) {
5923 int l = min(4 - c->u.a.lensofar, length);
5924 memcpy(c->u.a.msglen + c->u.a.lensofar,
5925 data, l);
5926 data += l;
5927 length -= l;
5928 c->u.a.lensofar += l;
5929 }
5930 if (c->u.a.lensofar == 4) {
5931 c->u.a.totallen =
5932 4 + GET_32BIT(c->u.a.msglen);
5933 c->u.a.message = snewn(c->u.a.totallen,
5934 unsigned char);
5935 memcpy(c->u.a.message, c->u.a.msglen, 4);
5936 }
5937 if (c->u.a.lensofar >= 4 && length > 0) {
5938 int l =
5939 min(c->u.a.totallen - c->u.a.lensofar,
5940 length);
5941 memcpy(c->u.a.message + c->u.a.lensofar,
5942 data, l);
5943 data += l;
5944 length -= l;
5945 c->u.a.lensofar += l;
5946 }
5947 if (c->u.a.lensofar == c->u.a.totallen) {
5948 void *reply;
5949 int replylen;
5950 if (agent_query(c->u.a.message,
5951 c->u.a.totallen,
5952 &reply, &replylen,
5953 ssh_agentf_callback, c))
5954 ssh_agentf_callback(c, reply, replylen);
5955 sfree(c->u.a.message);
5956 c->u.a.lensofar = 0;
5957 }
5958 }
5959 bufsize = 0;
5960 break;
5961 }
5962 /*
5963 * If we are not buffering too much data,
5964 * enlarge the window again at the remote side.
5965 */
5966 if (bufsize < OUR_V2_WINSIZE)
5967 ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
5968 }
5969 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_EOF) {
5970 unsigned i = ssh_pkt_getuint32(ssh);
5971 struct ssh_channel *c;
5972
5973 c = find234(ssh->channels, &i, ssh_channelfind);
5974 if (!c)
5975 continue; /* nonexistent channel */
5976
5977 if (c->type == CHAN_X11) {
5978 /*
5979 * Remote EOF on an X11 channel means we should
5980 * wrap up and close the channel ourselves.
5981 */
5982 x11_close(c->u.x11.s);
5983 sshfwd_close(c);
5984 } else if (c->type == CHAN_AGENT) {
5985 sshfwd_close(c);
5986 } else if (c->type == CHAN_SOCKDATA) {
5987 pfd_close(c->u.pfd.s);
5988 sshfwd_close(c);
5989 }
5990 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_CLOSE) {
5991 unsigned i = ssh_pkt_getuint32(ssh);
5992 struct ssh_channel *c;
5993
5994 c = find234(ssh->channels, &i, ssh_channelfind);
5995 if (!c || ((int)c->remoteid) == -1) {
5996 bombout(("Received CHANNEL_CLOSE for %s channel %d\n",
5997 c ? "half-open" : "nonexistent", i));
5998 crStopV;
5999 }
6000 /* Do pre-close processing on the channel. */
6001 switch (c->type) {
6002 case CHAN_MAINSESSION:
6003 break; /* nothing to see here, move along */
6004 case CHAN_X11:
6005 if (c->u.x11.s != NULL)
6006 x11_close(c->u.x11.s);
6007 sshfwd_close(c);
6008 break;
6009 case CHAN_AGENT:
6010 sshfwd_close(c);
6011 break;
6012 case CHAN_SOCKDATA:
6013 if (c->u.pfd.s != NULL)
6014 pfd_close(c->u.pfd.s);
6015 sshfwd_close(c);
6016 break;
6017 }
6018 if (c->closes == 0) {
6019 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
6020 ssh2_pkt_adduint32(ssh, c->remoteid);
6021 ssh2_pkt_send(ssh);
6022 }
6023 del234(ssh->channels, c);
6024 bufchain_clear(&c->v.v2.outbuffer);
6025 sfree(c);
6026
6027 /*
6028 * See if that was the last channel left open.
6029 */
6030 if (count234(ssh->channels) == 0) {
6031 logevent("All channels closed. Disconnecting");
6032 #if 0
6033 /*
6034 * We used to send SSH_MSG_DISCONNECT here,
6035 * because I'd believed that _every_ conforming
6036 * SSH2 connection had to end with a disconnect
6037 * being sent by at least one side; apparently
6038 * I was wrong and it's perfectly OK to
6039 * unceremoniously slam the connection shut
6040 * when you're done, and indeed OpenSSH feels
6041 * this is more polite than sending a
6042 * DISCONNECT. So now we don't.
6043 */
6044 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
6045 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
6046 ssh2_pkt_addstring(ssh, "All open channels closed");
6047 ssh2_pkt_addstring(ssh, "en"); /* language tag */
6048 ssh2_pkt_send(ssh);
6049 #endif
6050 ssh_closing((Plug)ssh, NULL, 0, 0);
6051 crStopV;
6052 }
6053 continue; /* remote sends close; ignore (FIXME) */
6054 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
6055 unsigned i = ssh_pkt_getuint32(ssh);
6056 struct ssh_channel *c;
6057 c = find234(ssh->channels, &i, ssh_channelfind);
6058 if (!c || c->closes)
6059 continue; /* nonexistent or closing channel */
6060 c->v.v2.remwindow += ssh_pkt_getuint32(ssh);
6061 s->try_send = TRUE;
6062 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
6063 unsigned i = ssh_pkt_getuint32(ssh);
6064 struct ssh_channel *c;
6065 c = find234(ssh->channels, &i, ssh_channelfind);
6066 if (!c)
6067 continue; /* nonexistent channel */
6068 if (c->type != CHAN_SOCKDATA_DORMANT)
6069 continue; /* dunno why they're confirming this */
6070 c->remoteid = ssh_pkt_getuint32(ssh);
6071 c->type = CHAN_SOCKDATA;
6072 c->v.v2.remwindow = ssh_pkt_getuint32(ssh);
6073 c->v.v2.remmaxpkt = ssh_pkt_getuint32(ssh);
6074 if (c->u.pfd.s)
6075 pfd_confirm(c->u.pfd.s);
6076 if (c->closes) {
6077 /*
6078 * We have a pending close on this channel,
6079 * which we decided on before the server acked
6080 * the channel open. So now we know the
6081 * remoteid, we can close it again.
6082 */
6083 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
6084 ssh2_pkt_adduint32(ssh, c->remoteid);
6085 ssh2_pkt_send(ssh);
6086 }
6087 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN_FAILURE) {
6088 static const char *const reasons[] = {
6089 "<unknown reason code>",
6090 "Administratively prohibited",
6091 "Connect failed",
6092 "Unknown channel type",
6093 "Resource shortage",
6094 };
6095 unsigned i = ssh_pkt_getuint32(ssh);
6096 unsigned reason_code;
6097 char *reason_string;
6098 int reason_length;
6099 char *message;
6100 struct ssh_channel *c;
6101 c = find234(ssh->channels, &i, ssh_channelfind);
6102 if (!c)
6103 continue; /* nonexistent channel */
6104 if (c->type != CHAN_SOCKDATA_DORMANT)
6105 continue; /* dunno why they're failing this */
6106
6107 reason_code = ssh_pkt_getuint32(ssh);
6108 if (reason_code >= lenof(reasons))
6109 reason_code = 0; /* ensure reasons[reason_code] in range */
6110 ssh_pkt_getstring(ssh, &reason_string, &reason_length);
6111 message = dupprintf("Forwarded connection refused by"
6112 " server: %s [%.*s]", reasons[reason_code],
6113 reason_length, reason_string);
6114 logevent(message);
6115 sfree(message);
6116
6117 pfd_close(c->u.pfd.s);
6118
6119 del234(ssh->channels, c);
6120 sfree(c);
6121 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_REQUEST) {
6122 unsigned localid;
6123 char *type;
6124 int typelen, want_reply;
6125 struct ssh_channel *c;
6126
6127 localid = ssh_pkt_getuint32(ssh);
6128 ssh_pkt_getstring(ssh, &type, &typelen);
6129 want_reply = ssh2_pkt_getbool(ssh);
6130
6131 /*
6132 * First, check that the channel exists. Otherwise,
6133 * we can instantly disconnect with a rude message.
6134 */
6135 c = find234(ssh->channels, &localid, ssh_channelfind);
6136 if (!c) {
6137 char buf[80];
6138 sprintf(buf, "Received channel request for nonexistent"
6139 " channel %d", localid);
6140 logevent(buf);
6141 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
6142 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
6143 ssh2_pkt_addstring(ssh, buf);
6144 ssh2_pkt_addstring(ssh, "en"); /* language tag */
6145 ssh2_pkt_send(ssh);
6146 connection_fatal(ssh->frontend, "%s", buf);
6147 ssh_closing((Plug)ssh, NULL, 0, 0);
6148 crStopV;
6149 }
6150
6151 /*
6152 * Having got the channel number, we now look at
6153 * the request type string to see if it's something
6154 * we recognise.
6155 */
6156 if (typelen == 11 && !memcmp(type, "exit-status", 11) &&
6157 c == ssh->mainchan) {
6158 /* We recognise "exit-status" on the primary channel. */
6159 char buf[100];
6160 ssh->exitcode = ssh_pkt_getuint32(ssh);
6161 sprintf(buf, "Server sent command exit status %d",
6162 ssh->exitcode);
6163 logevent(buf);
6164 if (want_reply) {
6165 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_SUCCESS);
6166 ssh2_pkt_adduint32(ssh, c->remoteid);
6167 ssh2_pkt_send(ssh);
6168 }
6169 } else {
6170 /*
6171 * This is a channel request we don't know
6172 * about, so we now either ignore the request
6173 * or respond with CHANNEL_FAILURE, depending
6174 * on want_reply.
6175 */
6176 if (want_reply) {
6177 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_FAILURE);
6178 ssh2_pkt_adduint32(ssh, c->remoteid);
6179 ssh2_pkt_send(ssh);
6180 }
6181 }
6182 } else if (ssh->pktin.type == SSH2_MSG_GLOBAL_REQUEST) {
6183 char *type;
6184 int typelen, want_reply;
6185
6186 ssh_pkt_getstring(ssh, &type, &typelen);
6187 want_reply = ssh2_pkt_getbool(ssh);
6188
6189 /*
6190 * We currently don't support any global requests
6191 * at all, so we either ignore the request or
6192 * respond with REQUEST_FAILURE, depending on
6193 * want_reply.
6194 */
6195 if (want_reply) {
6196 ssh2_pkt_init(ssh, SSH2_MSG_REQUEST_FAILURE);
6197 ssh2_pkt_send(ssh);
6198 }
6199 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN) {
6200 char *type;
6201 int typelen;
6202 char *peeraddr;
6203 int peeraddrlen;
6204 int peerport;
6205 char *error = NULL;
6206 struct ssh_channel *c;
6207 unsigned remid, winsize, pktsize;
6208 ssh_pkt_getstring(ssh, &type, &typelen);
6209 c = snew(struct ssh_channel);
6210 c->ssh = ssh;
6211
6212 remid = ssh_pkt_getuint32(ssh);
6213 winsize = ssh_pkt_getuint32(ssh);
6214 pktsize = ssh_pkt_getuint32(ssh);
6215
6216 if (typelen == 3 && !memcmp(type, "x11", 3)) {
6217 char *addrstr;
6218
6219 ssh_pkt_getstring(ssh, &peeraddr, &peeraddrlen);
6220 addrstr = snewn(peeraddrlen+1, char);
6221 memcpy(addrstr, peeraddr, peeraddrlen);
6222 addrstr[peeraddrlen] = '\0';
6223 peerport = ssh_pkt_getuint32(ssh);
6224
6225 logeventf(ssh, "Received X11 connect request from %s:%d",
6226 addrstr, peerport);
6227
6228 if (!ssh->X11_fwd_enabled)
6229 error = "X11 forwarding is not enabled";
6230 else if (x11_init(&c->u.x11.s, ssh->cfg.x11_display, c,
6231 ssh->x11auth, addrstr, peerport,
6232 &ssh->cfg) != NULL) {
6233 error = "Unable to open an X11 connection";
6234 } else {
6235 logevent("Opening X11 forward connection succeeded");
6236 c->type = CHAN_X11;
6237 }
6238
6239 sfree(addrstr);
6240 } else if (typelen == 15 &&
6241 !memcmp(type, "forwarded-tcpip", 15)) {
6242 struct ssh_rportfwd pf, *realpf;
6243 char *dummy;
6244 int dummylen;
6245 ssh_pkt_getstring(ssh, &dummy, &dummylen);/* skip address */
6246 pf.sport = ssh_pkt_getuint32(ssh);
6247 ssh_pkt_getstring(ssh, &peeraddr, &peeraddrlen);
6248 peerport = ssh_pkt_getuint32(ssh);
6249 realpf = find234(ssh->rportfwds, &pf, NULL);
6250 logeventf(ssh, "Received remote port %d open request "
6251 "from %s:%d", pf.sport, peeraddr, peerport);
6252 if (realpf == NULL) {
6253 error = "Remote port is not recognised";
6254 } else {
6255 const char *e = pfd_newconnect(&c->u.pfd.s,
6256 realpf->dhost,
6257 realpf->dport, c,
6258 &ssh->cfg);
6259 logeventf(ssh, "Attempting to forward remote port to "
6260 "%s:%d", realpf->dhost, realpf->dport);
6261 if (e != NULL) {
6262 logeventf(ssh, "Port open failed: %s", e);
6263 error = "Port open failed";
6264 } else {
6265 logevent("Forwarded port opened successfully");
6266 c->type = CHAN_SOCKDATA;
6267 }
6268 }
6269 } else if (typelen == 22 &&
6270 !memcmp(type, "auth-agent@openssh.com", 3)) {
6271 if (!ssh->agentfwd_enabled)
6272 error = "Agent forwarding is not enabled";
6273 else {
6274 c->type = CHAN_AGENT; /* identify channel type */
6275 c->u.a.lensofar = 0;
6276 }
6277 } else {
6278 error = "Unsupported channel type requested";
6279 }
6280
6281 c->remoteid = remid;
6282 if (error) {
6283 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN_FAILURE);
6284 ssh2_pkt_adduint32(ssh, c->remoteid);
6285 ssh2_pkt_adduint32(ssh, SSH2_OPEN_CONNECT_FAILED);
6286 ssh2_pkt_addstring(ssh, error);
6287 ssh2_pkt_addstring(ssh, "en"); /* language tag */
6288 ssh2_pkt_send(ssh);
6289 logeventf(ssh, "Rejected channel open: %s", error);
6290 sfree(c);
6291 } else {
6292 c->localid = alloc_channel_id(ssh);
6293 c->closes = 0;
6294 c->v.v2.locwindow = OUR_V2_WINSIZE;
6295 c->v.v2.remwindow = winsize;
6296 c->v.v2.remmaxpkt = pktsize;
6297 bufchain_init(&c->v.v2.outbuffer);
6298 add234(ssh->channels, c);
6299 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
6300 ssh2_pkt_adduint32(ssh, c->remoteid);
6301 ssh2_pkt_adduint32(ssh, c->localid);
6302 ssh2_pkt_adduint32(ssh, c->v.v2.locwindow);
6303 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
6304 ssh2_pkt_send(ssh);
6305 }
6306 } else {
6307 bombout(("Strange packet received: type %d", ssh->pktin.type));
6308 crStopV;
6309 }
6310 } else {
6311 /*
6312 * We have spare data. Add it to the channel buffer.
6313 */
6314 ssh2_add_channel_data(ssh->mainchan, (char *)in, inlen);
6315 s->try_send = TRUE;
6316 }
6317 if (s->try_send) {
6318 int i;
6319 struct ssh_channel *c;
6320 /*
6321 * Try to send data on all channels if we can.
6322 */
6323 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
6324 int bufsize;
6325 if (c->closes)
6326 continue; /* don't send on closing channels */
6327 bufsize = ssh2_try_send(c);
6328 if (bufsize == 0) {
6329 switch (c->type) {
6330 case CHAN_MAINSESSION:
6331 /* stdin need not receive an unthrottle
6332 * notification since it will be polled */
6333 break;
6334 case CHAN_X11:
6335 x11_unthrottle(c->u.x11.s);
6336 break;
6337 case CHAN_AGENT:
6338 /* agent sockets are request/response and need no
6339 * buffer management */
6340 break;
6341 case CHAN_SOCKDATA:
6342 pfd_unthrottle(c->u.pfd.s);
6343 break;
6344 }
6345 }
6346 }
6347 }
6348 }
6349
6350 crFinishV;
6351 }
6352
6353 /*
6354 * Handle the top-level SSH2 protocol.
6355 */
6356 static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
6357 {
6358 if (do_ssh2_transport(ssh, in, inlen, ispkt) == 0)
6359 return;
6360 do_ssh2_authconn(ssh, in, inlen, ispkt);
6361 }
6362
6363 /*
6364 * Called to set up the connection.
6365 *
6366 * Returns an error message, or NULL on success.
6367 */
6368 static const char *ssh_init(void *frontend_handle, void **backend_handle,
6369 Config *cfg,
6370 char *host, int port, char **realhost, int nodelay,
6371 int keepalive)
6372 {
6373 const char *p;
6374 Ssh ssh;
6375
6376 ssh = snew(struct ssh_tag);
6377 ssh->cfg = *cfg; /* STRUCTURE COPY */
6378 ssh->version = 0; /* when not ready yet */
6379 ssh->s = NULL;
6380 ssh->cipher = NULL;
6381 ssh->v1_cipher_ctx = NULL;
6382 ssh->crcda_ctx = NULL;
6383 ssh->cscipher = NULL;
6384 ssh->cs_cipher_ctx = NULL;
6385 ssh->sccipher = NULL;
6386 ssh->sc_cipher_ctx = NULL;
6387 ssh->csmac = NULL;
6388 ssh->cs_mac_ctx = NULL;
6389 ssh->scmac = NULL;
6390 ssh->sc_mac_ctx = NULL;
6391 ssh->cscomp = NULL;
6392 ssh->cs_comp_ctx = NULL;
6393 ssh->sccomp = NULL;
6394 ssh->sc_comp_ctx = NULL;
6395 ssh->kex = NULL;
6396 ssh->kex_ctx = NULL;
6397 ssh->hostkey = NULL;
6398 ssh->exitcode = -1;
6399 ssh->state = SSH_STATE_PREPACKET;
6400 ssh->size_needed = FALSE;
6401 ssh->eof_needed = FALSE;
6402 ssh->ldisc = NULL;
6403 ssh->logctx = NULL;
6404 {
6405 static const struct Packet empty = { 0, 0, NULL, NULL, 0 };
6406 ssh->pktin = ssh->pktout = empty;
6407 }
6408 ssh->deferred_send_data = NULL;
6409 ssh->deferred_len = 0;
6410 ssh->deferred_size = 0;
6411 ssh->fallback_cmd = 0;
6412 ssh->pkt_ctx = 0;
6413 ssh->x11auth = NULL;
6414 ssh->v1_compressing = FALSE;
6415 ssh->v2_outgoing_sequence = 0;
6416 ssh->ssh1_rdpkt_crstate = 0;
6417 ssh->ssh2_rdpkt_crstate = 0;
6418 ssh->do_ssh_init_crstate = 0;
6419 ssh->ssh_gotdata_crstate = 0;
6420 ssh->ssh1_protocol_crstate = 0;
6421 ssh->do_ssh1_login_crstate = 0;
6422 ssh->do_ssh2_transport_crstate = 0;
6423 ssh->do_ssh2_authconn_crstate = 0;
6424 ssh->do_ssh_init_state = NULL;
6425 ssh->do_ssh1_login_state = NULL;
6426 ssh->do_ssh2_transport_state = NULL;
6427 ssh->do_ssh2_authconn_state = NULL;
6428 ssh->mainchan = NULL;
6429 ssh->throttled_all = 0;
6430 ssh->v1_stdout_throttling = 0;
6431
6432 *backend_handle = ssh;
6433
6434 #ifdef MSCRYPTOAPI
6435 if (crypto_startup() == 0)
6436 return "Microsoft high encryption pack not installed!";
6437 #endif
6438
6439 ssh->frontend = frontend_handle;
6440 ssh->term_width = ssh->cfg.width;
6441 ssh->term_height = ssh->cfg.height;
6442
6443 ssh->channels = NULL;
6444 ssh->rportfwds = NULL;
6445
6446 ssh->send_ok = 0;
6447 ssh->editing = 0;
6448 ssh->echoing = 0;
6449 ssh->v1_throttle_count = 0;
6450 ssh->overall_bufsize = 0;
6451 ssh->fallback_cmd = 0;
6452
6453 ssh->protocol = NULL;
6454
6455 p = connect_to_host(ssh, host, port, realhost, nodelay, keepalive);
6456 if (p != NULL)
6457 return p;
6458
6459 return NULL;
6460 }
6461
6462 static void ssh_free(void *handle)
6463 {
6464 Ssh ssh = (Ssh) handle;
6465 struct ssh_channel *c;
6466 struct ssh_rportfwd *pf;
6467
6468 if (ssh->v1_cipher_ctx)
6469 ssh->cipher->free_context(ssh->v1_cipher_ctx);
6470 if (ssh->cs_cipher_ctx)
6471 ssh->cscipher->free_context(ssh->cs_cipher_ctx);
6472 if (ssh->sc_cipher_ctx)
6473 ssh->sccipher->free_context(ssh->sc_cipher_ctx);
6474 if (ssh->cs_mac_ctx)
6475 ssh->csmac->free_context(ssh->cs_mac_ctx);
6476 if (ssh->sc_mac_ctx)
6477 ssh->scmac->free_context(ssh->sc_mac_ctx);
6478 if (ssh->cs_comp_ctx) {
6479 if (ssh->cscomp)
6480 ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
6481 else
6482 zlib_compress_cleanup(ssh->cs_comp_ctx);
6483 }
6484 if (ssh->sc_comp_ctx) {
6485 if (ssh->sccomp)
6486 ssh->sccomp->decompress_cleanup(ssh->sc_comp_ctx);
6487 else
6488 zlib_decompress_cleanup(ssh->sc_comp_ctx);
6489 }
6490 if (ssh->kex_ctx)
6491 dh_cleanup(ssh->kex_ctx);
6492 sfree(ssh->savedhost);
6493
6494 if (ssh->channels) {
6495 while ((c = delpos234(ssh->channels, 0)) != NULL) {
6496 switch (c->type) {
6497 case CHAN_X11:
6498 if (c->u.x11.s != NULL)
6499 x11_close(c->u.x11.s);
6500 break;
6501 case CHAN_SOCKDATA:
6502 if (c->u.pfd.s != NULL)
6503 pfd_close(c->u.pfd.s);
6504 break;
6505 }
6506 sfree(c);
6507 }
6508 freetree234(ssh->channels);
6509 }
6510
6511 if (ssh->rportfwds) {
6512 while ((pf = delpos234(ssh->rportfwds, 0)) != NULL)
6513 sfree(pf);
6514 freetree234(ssh->rportfwds);
6515 }
6516 sfree(ssh->deferred_send_data);
6517 if (ssh->x11auth)
6518 x11_free_auth(ssh->x11auth);
6519 sfree(ssh->do_ssh_init_state);
6520 sfree(ssh->do_ssh1_login_state);
6521 sfree(ssh->do_ssh2_transport_state);
6522 sfree(ssh->do_ssh2_authconn_state);
6523 if (ssh->pktout.data) {
6524 sfree(ssh->pktout.data);
6525 ssh->pktout.data = NULL;
6526 }
6527 if (ssh->pktin.data) {
6528 sfree(ssh->pktin.data);
6529 ssh->pktin.data = NULL;
6530 }
6531 if (ssh->crcda_ctx) {
6532 crcda_free_context(ssh->crcda_ctx);
6533 ssh->crcda_ctx = NULL;
6534 }
6535 if (ssh->s)
6536 ssh_do_close(ssh);
6537 sfree(ssh);
6538 }
6539
6540 /*
6541 * Reconfigure the SSH backend.
6542 *
6543 * Currently, this function does nothing very useful. In future,
6544 * however, we could do some handy things with it. For example, we
6545 * could make the port forwarding configurer active in the Change
6546 * Settings box, and this routine could close down existing
6547 * forwardings and open up new ones in response to changes.
6548 */
6549 static void ssh_reconfig(void *handle, Config *cfg)
6550 {
6551 Ssh ssh = (Ssh) handle;
6552 ssh->cfg = *cfg; /* STRUCTURE COPY */
6553 }
6554
6555 /*
6556 * Called to send data down the Telnet connection.
6557 */
6558 static int ssh_send(void *handle, char *buf, int len)
6559 {
6560 Ssh ssh = (Ssh) handle;
6561
6562 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
6563 return 0;
6564
6565 ssh->protocol(ssh, (unsigned char *)buf, len, 0);
6566
6567 return ssh_sendbuffer(ssh);
6568 }
6569
6570 /*
6571 * Called to query the current amount of buffered stdin data.
6572 */
6573 static int ssh_sendbuffer(void *handle)
6574 {
6575 Ssh ssh = (Ssh) handle;
6576 int override_value;
6577
6578 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
6579 return 0;
6580
6581 /*
6582 * If the SSH socket itself has backed up, add the total backup
6583 * size on that to any individual buffer on the stdin channel.
6584 */
6585 override_value = 0;
6586 if (ssh->throttled_all)
6587 override_value = ssh->overall_bufsize;
6588
6589 if (ssh->version == 1) {
6590 return override_value;
6591 } else if (ssh->version == 2) {
6592 if (!ssh->mainchan || ssh->mainchan->closes > 0)
6593 return override_value;
6594 else
6595 return (override_value +
6596 bufchain_size(&ssh->mainchan->v.v2.outbuffer));
6597 }
6598
6599 return 0;
6600 }
6601
6602 /*
6603 * Called to set the size of the window from SSH's POV.
6604 */
6605 static void ssh_size(void *handle, int width, int height)
6606 {
6607 Ssh ssh = (Ssh) handle;
6608
6609 ssh->term_width = width;
6610 ssh->term_height = height;
6611
6612 switch (ssh->state) {
6613 case SSH_STATE_BEFORE_SIZE:
6614 case SSH_STATE_PREPACKET:
6615 case SSH_STATE_CLOSED:
6616 break; /* do nothing */
6617 case SSH_STATE_INTERMED:
6618 ssh->size_needed = TRUE; /* buffer for later */
6619 break;
6620 case SSH_STATE_SESSION:
6621 if (!ssh->cfg.nopty) {
6622 if (ssh->version == 1) {
6623 send_packet(ssh, SSH1_CMSG_WINDOW_SIZE,
6624 PKT_INT, ssh->term_height,
6625 PKT_INT, ssh->term_width,
6626 PKT_INT, 0, PKT_INT, 0, PKT_END);
6627 } else {
6628 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
6629 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
6630 ssh2_pkt_addstring(ssh, "window-change");
6631 ssh2_pkt_addbool(ssh, 0);
6632 ssh2_pkt_adduint32(ssh, ssh->term_width);
6633 ssh2_pkt_adduint32(ssh, ssh->term_height);
6634 ssh2_pkt_adduint32(ssh, 0);
6635 ssh2_pkt_adduint32(ssh, 0);
6636 ssh2_pkt_send(ssh);
6637 }
6638 }
6639 break;
6640 }
6641 }
6642
6643 /*
6644 * Return a list of the special codes that make sense in this
6645 * protocol.
6646 */
6647 static const struct telnet_special *ssh_get_specials(void *handle)
6648 {
6649 Ssh ssh = (Ssh) handle;
6650
6651 if (ssh->version == 1) {
6652 static const struct telnet_special ssh1_specials[] = {
6653 {"IGNORE message", TS_NOP},
6654 {NULL, 0}
6655 };
6656 return ssh1_specials;
6657 } else if (ssh->version == 2) {
6658 static const struct telnet_special ssh2_specials[] = {
6659 {"Break", TS_BRK},
6660 {"IGNORE message", TS_NOP},
6661 {NULL, 0}
6662 };
6663 return ssh2_specials;
6664 } else
6665 return NULL;
6666 }
6667
6668 /*
6669 * Send Telnet special codes. TS_EOF is useful for `plink', so you
6670 * can send an EOF and collect resulting output (e.g. `plink
6671 * hostname sort').
6672 */
6673 static void ssh_special(void *handle, Telnet_Special code)
6674 {
6675 Ssh ssh = (Ssh) handle;
6676
6677 if (code == TS_EOF) {
6678 if (ssh->state != SSH_STATE_SESSION) {
6679 /*
6680 * Buffer the EOF in case we are pre-SESSION, so we can
6681 * send it as soon as we reach SESSION.
6682 */
6683 if (code == TS_EOF)
6684 ssh->eof_needed = TRUE;
6685 return;
6686 }
6687 if (ssh->version == 1) {
6688 send_packet(ssh, SSH1_CMSG_EOF, PKT_END);
6689 } else {
6690 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_EOF);
6691 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
6692 ssh2_pkt_send(ssh);
6693 }
6694 logevent("Sent EOF message");
6695 } else if (code == TS_PING || code == TS_NOP) {
6696 if (ssh->state == SSH_STATE_CLOSED
6697 || ssh->state == SSH_STATE_PREPACKET) return;
6698 if (ssh->version == 1) {
6699 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE))
6700 send_packet(ssh, SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
6701 } else {
6702 ssh2_pkt_init(ssh, SSH2_MSG_IGNORE);
6703 ssh2_pkt_addstring_start(ssh);
6704 ssh2_pkt_send(ssh);
6705 }
6706 } else if (code == TS_BRK) {
6707 if (ssh->state == SSH_STATE_CLOSED
6708 || ssh->state == SSH_STATE_PREPACKET) return;
6709 if (ssh->version == 1) {
6710 logevent("Unable to send BREAK signal in SSH1");
6711 } else {
6712 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
6713 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
6714 ssh2_pkt_addstring(ssh, "break");
6715 ssh2_pkt_addbool(ssh, 0);
6716 ssh2_pkt_adduint32(ssh, 0); /* default break length */
6717 ssh2_pkt_send(ssh);
6718 }
6719 } else {
6720 /* do nothing */
6721 }
6722 }
6723
6724 void *new_sock_channel(void *handle, Socket s)
6725 {
6726 Ssh ssh = (Ssh) handle;
6727 struct ssh_channel *c;
6728 c = snew(struct ssh_channel);
6729 c->ssh = ssh;
6730
6731 if (c) {
6732 c->remoteid = -1; /* to be set when open confirmed */
6733 c->localid = alloc_channel_id(ssh);
6734 c->closes = 0;
6735 c->type = CHAN_SOCKDATA_DORMANT;/* identify channel type */
6736 c->u.pfd.s = s;
6737 bufchain_init(&c->v.v2.outbuffer);
6738 add234(ssh->channels, c);
6739 }
6740 return c;
6741 }
6742
6743 /*
6744 * This is called when stdout/stderr (the entity to which
6745 * from_backend sends data) manages to clear some backlog.
6746 */
6747 static void ssh_unthrottle(void *handle, int bufsize)
6748 {
6749 Ssh ssh = (Ssh) handle;
6750 if (ssh->version == 1) {
6751 if (ssh->v1_stdout_throttling && bufsize < SSH1_BUFFER_LIMIT) {
6752 ssh->v1_stdout_throttling = 0;
6753 ssh1_throttle(ssh, -1);
6754 }
6755 } else {
6756 if (ssh->mainchan && ssh->mainchan->closes == 0)
6757 ssh2_set_window(ssh->mainchan, OUR_V2_WINSIZE - bufsize);
6758 }
6759 }
6760
6761 void ssh_send_port_open(void *channel, char *hostname, int port, char *org)
6762 {
6763 struct ssh_channel *c = (struct ssh_channel *)channel;
6764 Ssh ssh = c->ssh;
6765
6766 logeventf(ssh, "Opening forwarded connection to %s:%d", hostname, port);
6767
6768 if (ssh->version == 1) {
6769 send_packet(ssh, SSH1_MSG_PORT_OPEN,
6770 PKT_INT, c->localid,
6771 PKT_STR, hostname,
6772 PKT_INT, port,
6773 //PKT_STR, <org:orgport>,
6774 PKT_END);
6775 } else {
6776 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN);
6777 ssh2_pkt_addstring(ssh, "direct-tcpip");
6778 ssh2_pkt_adduint32(ssh, c->localid);
6779 c->v.v2.locwindow = OUR_V2_WINSIZE;
6780 ssh2_pkt_adduint32(ssh, c->v.v2.locwindow);/* our window size */
6781 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
6782 ssh2_pkt_addstring(ssh, hostname);
6783 ssh2_pkt_adduint32(ssh, port);
6784 /*
6785 * We make up values for the originator data; partly it's
6786 * too much hassle to keep track, and partly I'm not
6787 * convinced the server should be told details like that
6788 * about my local network configuration.
6789 */
6790 ssh2_pkt_addstring(ssh, "client-side-connection");
6791 ssh2_pkt_adduint32(ssh, 0);
6792 ssh2_pkt_send(ssh);
6793 }
6794 }
6795
6796
6797 static Socket ssh_socket(void *handle)
6798 {
6799 Ssh ssh = (Ssh) handle;
6800 return ssh->s;
6801 }
6802
6803 static int ssh_sendok(void *handle)
6804 {
6805 Ssh ssh = (Ssh) handle;
6806 return ssh->send_ok;
6807 }
6808
6809 static int ssh_ldisc(void *handle, int option)
6810 {
6811 Ssh ssh = (Ssh) handle;
6812 if (option == LD_ECHO)
6813 return ssh->echoing;
6814 if (option == LD_EDIT)
6815 return ssh->editing;
6816 return FALSE;
6817 }
6818
6819 static void ssh_provide_ldisc(void *handle, void *ldisc)
6820 {
6821 Ssh ssh = (Ssh) handle;
6822 ssh->ldisc = ldisc;
6823 }
6824
6825 static void ssh_provide_logctx(void *handle, void *logctx)
6826 {
6827 Ssh ssh = (Ssh) handle;
6828 ssh->logctx = logctx;
6829 }
6830
6831 static int ssh_return_exitcode(void *handle)
6832 {
6833 Ssh ssh = (Ssh) handle;
6834 if (ssh->s != NULL)
6835 return -1;
6836 else
6837 return (ssh->exitcode >= 0 ? ssh->exitcode : 0);
6838 }
6839
6840 /*
6841 * Gross hack: pscp will try to start SFTP but fall back to scp1 if
6842 * that fails. This variable is the means by which scp.c can reach
6843 * into the SSH code and find out which one it got.
6844 */
6845 extern int ssh_fallback_cmd(void *handle)
6846 {
6847 Ssh ssh = (Ssh) handle;
6848 return ssh->fallback_cmd;
6849 }
6850
6851 Backend ssh_backend = {
6852 ssh_init,
6853 ssh_free,
6854 ssh_reconfig,
6855 ssh_send,
6856 ssh_sendbuffer,
6857 ssh_size,
6858 ssh_special,
6859 ssh_get_specials,
6860 ssh_socket,
6861 ssh_return_exitcode,
6862 ssh_sendok,
6863 ssh_ldisc,
6864 ssh_provide_ldisc,
6865 ssh_provide_logctx,
6866 ssh_unthrottle,
6867 22
6868 };
Simon Tatham's PuTTY GUI SSH client; import of svn://svn.tartarus.org/sgt/putty