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Merged SSH1 robustness changes from 0.55 release branch on to trunk.
[u/mdw/putty] / ssh.c
1 #include <stdio.h>
2 #include <stdlib.h>
3 #include <stdarg.h>
4 #include <assert.h>
5
6 #include "putty.h"
7 #include "tree234.h"
8 #include "ssh.h"
9
10 #ifndef FALSE
11 #define FALSE 0
12 #endif
13 #ifndef TRUE
14 #define TRUE 1
15 #endif
16
17 #define SSH1_MSG_DISCONNECT 1 /* 0x1 */
18 #define SSH1_SMSG_PUBLIC_KEY 2 /* 0x2 */
19 #define SSH1_CMSG_SESSION_KEY 3 /* 0x3 */
20 #define SSH1_CMSG_USER 4 /* 0x4 */
21 #define SSH1_CMSG_AUTH_RSA 6 /* 0x6 */
22 #define SSH1_SMSG_AUTH_RSA_CHALLENGE 7 /* 0x7 */
23 #define SSH1_CMSG_AUTH_RSA_RESPONSE 8 /* 0x8 */
24 #define SSH1_CMSG_AUTH_PASSWORD 9 /* 0x9 */
25 #define SSH1_CMSG_REQUEST_PTY 10 /* 0xa */
26 #define SSH1_CMSG_WINDOW_SIZE 11 /* 0xb */
27 #define SSH1_CMSG_EXEC_SHELL 12 /* 0xc */
28 #define SSH1_CMSG_EXEC_CMD 13 /* 0xd */
29 #define SSH1_SMSG_SUCCESS 14 /* 0xe */
30 #define SSH1_SMSG_FAILURE 15 /* 0xf */
31 #define SSH1_CMSG_STDIN_DATA 16 /* 0x10 */
32 #define SSH1_SMSG_STDOUT_DATA 17 /* 0x11 */
33 #define SSH1_SMSG_STDERR_DATA 18 /* 0x12 */
34 #define SSH1_CMSG_EOF 19 /* 0x13 */
35 #define SSH1_SMSG_EXIT_STATUS 20 /* 0x14 */
36 #define SSH1_MSG_CHANNEL_OPEN_CONFIRMATION 21 /* 0x15 */
37 #define SSH1_MSG_CHANNEL_OPEN_FAILURE 22 /* 0x16 */
38 #define SSH1_MSG_CHANNEL_DATA 23 /* 0x17 */
39 #define SSH1_MSG_CHANNEL_CLOSE 24 /* 0x18 */
40 #define SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION 25 /* 0x19 */
41 #define SSH1_SMSG_X11_OPEN 27 /* 0x1b */
42 #define SSH1_CMSG_PORT_FORWARD_REQUEST 28 /* 0x1c */
43 #define SSH1_MSG_PORT_OPEN 29 /* 0x1d */
44 #define SSH1_CMSG_AGENT_REQUEST_FORWARDING 30 /* 0x1e */
45 #define SSH1_SMSG_AGENT_OPEN 31 /* 0x1f */
46 #define SSH1_MSG_IGNORE 32 /* 0x20 */
47 #define SSH1_CMSG_EXIT_CONFIRMATION 33 /* 0x21 */
48 #define SSH1_CMSG_X11_REQUEST_FORWARDING 34 /* 0x22 */
49 #define SSH1_CMSG_AUTH_RHOSTS_RSA 35 /* 0x23 */
50 #define SSH1_MSG_DEBUG 36 /* 0x24 */
51 #define SSH1_CMSG_REQUEST_COMPRESSION 37 /* 0x25 */
52 #define SSH1_CMSG_AUTH_TIS 39 /* 0x27 */
53 #define SSH1_SMSG_AUTH_TIS_CHALLENGE 40 /* 0x28 */
54 #define SSH1_CMSG_AUTH_TIS_RESPONSE 41 /* 0x29 */
55 #define SSH1_CMSG_AUTH_CCARD 70 /* 0x46 */
56 #define SSH1_SMSG_AUTH_CCARD_CHALLENGE 71 /* 0x47 */
57 #define SSH1_CMSG_AUTH_CCARD_RESPONSE 72 /* 0x48 */
58
59 #define SSH1_AUTH_TIS 5 /* 0x5 */
60 #define SSH1_AUTH_CCARD 16 /* 0x10 */
61
62 #define SSH1_PROTOFLAG_SCREEN_NUMBER 1 /* 0x1 */
63 /* Mask for protoflags we will echo back to server if seen */
64 #define SSH1_PROTOFLAGS_SUPPORTED 0 /* 0x1 */
65
66 #define SSH2_MSG_DISCONNECT 1 /* 0x1 */
67 #define SSH2_MSG_IGNORE 2 /* 0x2 */
68 #define SSH2_MSG_UNIMPLEMENTED 3 /* 0x3 */
69 #define SSH2_MSG_DEBUG 4 /* 0x4 */
70 #define SSH2_MSG_SERVICE_REQUEST 5 /* 0x5 */
71 #define SSH2_MSG_SERVICE_ACCEPT 6 /* 0x6 */
72 #define SSH2_MSG_KEXINIT 20 /* 0x14 */
73 #define SSH2_MSG_NEWKEYS 21 /* 0x15 */
74 #define SSH2_MSG_KEXDH_INIT 30 /* 0x1e */
75 #define SSH2_MSG_KEXDH_REPLY 31 /* 0x1f */
76 #define SSH2_MSG_KEX_DH_GEX_REQUEST 30 /* 0x1e */
77 #define SSH2_MSG_KEX_DH_GEX_GROUP 31 /* 0x1f */
78 #define SSH2_MSG_KEX_DH_GEX_INIT 32 /* 0x20 */
79 #define SSH2_MSG_KEX_DH_GEX_REPLY 33 /* 0x21 */
80 #define SSH2_MSG_USERAUTH_REQUEST 50 /* 0x32 */
81 #define SSH2_MSG_USERAUTH_FAILURE 51 /* 0x33 */
82 #define SSH2_MSG_USERAUTH_SUCCESS 52 /* 0x34 */
83 #define SSH2_MSG_USERAUTH_BANNER 53 /* 0x35 */
84 #define SSH2_MSG_USERAUTH_PK_OK 60 /* 0x3c */
85 #define SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ 60 /* 0x3c */
86 #define SSH2_MSG_USERAUTH_INFO_REQUEST 60 /* 0x3c */
87 #define SSH2_MSG_USERAUTH_INFO_RESPONSE 61 /* 0x3d */
88 #define SSH2_MSG_GLOBAL_REQUEST 80 /* 0x50 */
89 #define SSH2_MSG_REQUEST_SUCCESS 81 /* 0x51 */
90 #define SSH2_MSG_REQUEST_FAILURE 82 /* 0x52 */
91 #define SSH2_MSG_CHANNEL_OPEN 90 /* 0x5a */
92 #define SSH2_MSG_CHANNEL_OPEN_CONFIRMATION 91 /* 0x5b */
93 #define SSH2_MSG_CHANNEL_OPEN_FAILURE 92 /* 0x5c */
94 #define SSH2_MSG_CHANNEL_WINDOW_ADJUST 93 /* 0x5d */
95 #define SSH2_MSG_CHANNEL_DATA 94 /* 0x5e */
96 #define SSH2_MSG_CHANNEL_EXTENDED_DATA 95 /* 0x5f */
97 #define SSH2_MSG_CHANNEL_EOF 96 /* 0x60 */
98 #define SSH2_MSG_CHANNEL_CLOSE 97 /* 0x61 */
99 #define SSH2_MSG_CHANNEL_REQUEST 98 /* 0x62 */
100 #define SSH2_MSG_CHANNEL_SUCCESS 99 /* 0x63 */
101 #define SSH2_MSG_CHANNEL_FAILURE 100 /* 0x64 */
102
103 /*
104 * Packet type contexts, so that ssh2_pkt_type can correctly decode
105 * the ambiguous type numbers back into the correct type strings.
106 */
107 #define SSH2_PKTCTX_DHGROUP1 0x0001
108 #define SSH2_PKTCTX_DHGEX 0x0002
109 #define SSH2_PKTCTX_PUBLICKEY 0x0010
110 #define SSH2_PKTCTX_PASSWORD 0x0020
111 #define SSH2_PKTCTX_KBDINTER 0x0040
112 #define SSH2_PKTCTX_AUTH_MASK 0x00F0
113
114 #define SSH2_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT 1 /* 0x1 */
115 #define SSH2_DISCONNECT_PROTOCOL_ERROR 2 /* 0x2 */
116 #define SSH2_DISCONNECT_KEY_EXCHANGE_FAILED 3 /* 0x3 */
117 #define SSH2_DISCONNECT_HOST_AUTHENTICATION_FAILED 4 /* 0x4 */
118 #define SSH2_DISCONNECT_MAC_ERROR 5 /* 0x5 */
119 #define SSH2_DISCONNECT_COMPRESSION_ERROR 6 /* 0x6 */
120 #define SSH2_DISCONNECT_SERVICE_NOT_AVAILABLE 7 /* 0x7 */
121 #define SSH2_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED 8 /* 0x8 */
122 #define SSH2_DISCONNECT_HOST_KEY_NOT_VERIFIABLE 9 /* 0x9 */
123 #define SSH2_DISCONNECT_CONNECTION_LOST 10 /* 0xa */
124 #define SSH2_DISCONNECT_BY_APPLICATION 11 /* 0xb */
125 #define SSH2_DISCONNECT_TOO_MANY_CONNECTIONS 12 /* 0xc */
126 #define SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER 13 /* 0xd */
127 #define SSH2_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE 14 /* 0xe */
128 #define SSH2_DISCONNECT_ILLEGAL_USER_NAME 15 /* 0xf */
129
130 static const char *const ssh2_disconnect_reasons[] = {
131 NULL,
132 "SSH_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT",
133 "SSH_DISCONNECT_PROTOCOL_ERROR",
134 "SSH_DISCONNECT_KEY_EXCHANGE_FAILED",
135 "SSH_DISCONNECT_HOST_AUTHENTICATION_FAILED",
136 "SSH_DISCONNECT_MAC_ERROR",
137 "SSH_DISCONNECT_COMPRESSION_ERROR",
138 "SSH_DISCONNECT_SERVICE_NOT_AVAILABLE",
139 "SSH_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED",
140 "SSH_DISCONNECT_HOST_KEY_NOT_VERIFIABLE",
141 "SSH_DISCONNECT_CONNECTION_LOST",
142 "SSH_DISCONNECT_BY_APPLICATION",
143 "SSH_DISCONNECT_TOO_MANY_CONNECTIONS",
144 "SSH_DISCONNECT_AUTH_CANCELLED_BY_USER",
145 "SSH_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE",
146 "SSH_DISCONNECT_ILLEGAL_USER_NAME",
147 };
148
149 #define SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED 1 /* 0x1 */
150 #define SSH2_OPEN_CONNECT_FAILED 2 /* 0x2 */
151 #define SSH2_OPEN_UNKNOWN_CHANNEL_TYPE 3 /* 0x3 */
152 #define SSH2_OPEN_RESOURCE_SHORTAGE 4 /* 0x4 */
153
154 #define SSH2_EXTENDED_DATA_STDERR 1 /* 0x1 */
155
156 /*
157 * Various remote-bug flags.
158 */
159 #define BUG_CHOKES_ON_SSH1_IGNORE 1
160 #define BUG_SSH2_HMAC 2
161 #define BUG_NEEDS_SSH1_PLAIN_PASSWORD 4
162 #define BUG_CHOKES_ON_RSA 8
163 #define BUG_SSH2_RSA_PADDING 16
164 #define BUG_SSH2_DERIVEKEY 32
165 #define BUG_SSH2_DH_GEX 64
166 #define BUG_SSH2_PK_SESSIONID 128
167
168 #define translate(x) if (type == x) return #x
169 #define translatec(x,ctx) if (type == x && (pkt_ctx & ctx)) return #x
170 static char *ssh1_pkt_type(int type)
171 {
172 translate(SSH1_MSG_DISCONNECT);
173 translate(SSH1_SMSG_PUBLIC_KEY);
174 translate(SSH1_CMSG_SESSION_KEY);
175 translate(SSH1_CMSG_USER);
176 translate(SSH1_CMSG_AUTH_RSA);
177 translate(SSH1_SMSG_AUTH_RSA_CHALLENGE);
178 translate(SSH1_CMSG_AUTH_RSA_RESPONSE);
179 translate(SSH1_CMSG_AUTH_PASSWORD);
180 translate(SSH1_CMSG_REQUEST_PTY);
181 translate(SSH1_CMSG_WINDOW_SIZE);
182 translate(SSH1_CMSG_EXEC_SHELL);
183 translate(SSH1_CMSG_EXEC_CMD);
184 translate(SSH1_SMSG_SUCCESS);
185 translate(SSH1_SMSG_FAILURE);
186 translate(SSH1_CMSG_STDIN_DATA);
187 translate(SSH1_SMSG_STDOUT_DATA);
188 translate(SSH1_SMSG_STDERR_DATA);
189 translate(SSH1_CMSG_EOF);
190 translate(SSH1_SMSG_EXIT_STATUS);
191 translate(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION);
192 translate(SSH1_MSG_CHANNEL_OPEN_FAILURE);
193 translate(SSH1_MSG_CHANNEL_DATA);
194 translate(SSH1_MSG_CHANNEL_CLOSE);
195 translate(SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION);
196 translate(SSH1_SMSG_X11_OPEN);
197 translate(SSH1_CMSG_PORT_FORWARD_REQUEST);
198 translate(SSH1_MSG_PORT_OPEN);
199 translate(SSH1_CMSG_AGENT_REQUEST_FORWARDING);
200 translate(SSH1_SMSG_AGENT_OPEN);
201 translate(SSH1_MSG_IGNORE);
202 translate(SSH1_CMSG_EXIT_CONFIRMATION);
203 translate(SSH1_CMSG_X11_REQUEST_FORWARDING);
204 translate(SSH1_CMSG_AUTH_RHOSTS_RSA);
205 translate(SSH1_MSG_DEBUG);
206 translate(SSH1_CMSG_REQUEST_COMPRESSION);
207 translate(SSH1_CMSG_AUTH_TIS);
208 translate(SSH1_SMSG_AUTH_TIS_CHALLENGE);
209 translate(SSH1_CMSG_AUTH_TIS_RESPONSE);
210 translate(SSH1_CMSG_AUTH_CCARD);
211 translate(SSH1_SMSG_AUTH_CCARD_CHALLENGE);
212 translate(SSH1_CMSG_AUTH_CCARD_RESPONSE);
213 return "unknown";
214 }
215 static char *ssh2_pkt_type(int pkt_ctx, int type)
216 {
217 translate(SSH2_MSG_DISCONNECT);
218 translate(SSH2_MSG_IGNORE);
219 translate(SSH2_MSG_UNIMPLEMENTED);
220 translate(SSH2_MSG_DEBUG);
221 translate(SSH2_MSG_SERVICE_REQUEST);
222 translate(SSH2_MSG_SERVICE_ACCEPT);
223 translate(SSH2_MSG_KEXINIT);
224 translate(SSH2_MSG_NEWKEYS);
225 translatec(SSH2_MSG_KEXDH_INIT, SSH2_PKTCTX_DHGROUP1);
226 translatec(SSH2_MSG_KEXDH_REPLY, SSH2_PKTCTX_DHGROUP1);
227 translatec(SSH2_MSG_KEX_DH_GEX_REQUEST, SSH2_PKTCTX_DHGEX);
228 translatec(SSH2_MSG_KEX_DH_GEX_GROUP, SSH2_PKTCTX_DHGEX);
229 translatec(SSH2_MSG_KEX_DH_GEX_INIT, SSH2_PKTCTX_DHGEX);
230 translatec(SSH2_MSG_KEX_DH_GEX_REPLY, SSH2_PKTCTX_DHGEX);
231 translate(SSH2_MSG_USERAUTH_REQUEST);
232 translate(SSH2_MSG_USERAUTH_FAILURE);
233 translate(SSH2_MSG_USERAUTH_SUCCESS);
234 translate(SSH2_MSG_USERAUTH_BANNER);
235 translatec(SSH2_MSG_USERAUTH_PK_OK, SSH2_PKTCTX_PUBLICKEY);
236 translatec(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, SSH2_PKTCTX_PASSWORD);
237 translatec(SSH2_MSG_USERAUTH_INFO_REQUEST, SSH2_PKTCTX_KBDINTER);
238 translatec(SSH2_MSG_USERAUTH_INFO_RESPONSE, SSH2_PKTCTX_KBDINTER);
239 translate(SSH2_MSG_GLOBAL_REQUEST);
240 translate(SSH2_MSG_REQUEST_SUCCESS);
241 translate(SSH2_MSG_REQUEST_FAILURE);
242 translate(SSH2_MSG_CHANNEL_OPEN);
243 translate(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
244 translate(SSH2_MSG_CHANNEL_OPEN_FAILURE);
245 translate(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
246 translate(SSH2_MSG_CHANNEL_DATA);
247 translate(SSH2_MSG_CHANNEL_EXTENDED_DATA);
248 translate(SSH2_MSG_CHANNEL_EOF);
249 translate(SSH2_MSG_CHANNEL_CLOSE);
250 translate(SSH2_MSG_CHANNEL_REQUEST);
251 translate(SSH2_MSG_CHANNEL_SUCCESS);
252 translate(SSH2_MSG_CHANNEL_FAILURE);
253 return "unknown";
254 }
255 #undef translate
256 #undef translatec
257
258 #define GET_32BIT(cp) \
259 (((unsigned long)(unsigned char)(cp)[0] << 24) | \
260 ((unsigned long)(unsigned char)(cp)[1] << 16) | \
261 ((unsigned long)(unsigned char)(cp)[2] << 8) | \
262 ((unsigned long)(unsigned char)(cp)[3]))
263
264 #define PUT_32BIT(cp, value) { \
265 (cp)[0] = (unsigned char)((value) >> 24); \
266 (cp)[1] = (unsigned char)((value) >> 16); \
267 (cp)[2] = (unsigned char)((value) >> 8); \
268 (cp)[3] = (unsigned char)(value); }
269
270 enum { PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR, PKT_BIGNUM };
271
272 /*
273 * Coroutine mechanics for the sillier bits of the code. If these
274 * macros look impenetrable to you, you might find it helpful to
275 * read
276 *
277 * http://www.chiark.greenend.org.uk/~sgtatham/coroutines.html
278 *
279 * which explains the theory behind these macros.
280 *
281 * In particular, if you are getting `case expression not constant'
282 * errors when building with MS Visual Studio, this is because MS's
283 * Edit and Continue debugging feature causes their compiler to
284 * violate ANSI C. To disable Edit and Continue debugging:
285 *
286 * - right-click ssh.c in the FileView
287 * - click Settings
288 * - select the C/C++ tab and the General category
289 * - under `Debug info:', select anything _other_ than `Program
290 * Database for Edit and Continue'.
291 */
292 #define crBegin(v) { int *crLine = &v; switch(v) { case 0:;
293 #define crState(t) \
294 struct t *s; \
295 if (!ssh->t) ssh->t = snew(struct t); \
296 s = ssh->t;
297 #define crFinish(z) } *crLine = 0; return (z); }
298 #define crFinishV } *crLine = 0; return; }
299 #define crReturn(z) \
300 do {\
301 *crLine =__LINE__; return (z); case __LINE__:;\
302 } while (0)
303 #define crReturnV \
304 do {\
305 *crLine=__LINE__; return; case __LINE__:;\
306 } while (0)
307 #define crStop(z) do{ *crLine = 0; return (z); }while(0)
308 #define crStopV do{ *crLine = 0; return; }while(0)
309 #define crWaitUntil(c) do { crReturn(0); } while (!(c))
310 #define crWaitUntilV(c) do { crReturnV; } while (!(c))
311
312 typedef struct ssh_tag *Ssh;
313
314 static void ssh2_pkt_init(Ssh, int pkt_type);
315 static void ssh2_pkt_addbool(Ssh, unsigned char value);
316 static void ssh2_pkt_adduint32(Ssh, unsigned long value);
317 static void ssh2_pkt_addstring_start(Ssh);
318 static void ssh2_pkt_addstring_str(Ssh, char *data);
319 static void ssh2_pkt_addstring_data(Ssh, char *data, int len);
320 static void ssh2_pkt_addstring(Ssh, char *data);
321 static unsigned char *ssh2_mpint_fmt(Bignum b, int *len);
322 static void ssh2_pkt_addmp(Ssh, Bignum b);
323 static int ssh2_pkt_construct(Ssh);
324 static void ssh2_pkt_send(Ssh);
325 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 (ssh->pktin.maxlen < st->biglen) {
831 ssh->pktin.maxlen = st->biglen;
832 ssh->pktin.data = sresize(ssh->pktin.data, st->biglen + APIEXTRA,
833 unsigned char);
834 }
835
836 st->to_read = st->biglen;
837 st->p = ssh->pktin.data;
838 while (st->to_read > 0) {
839 st->chunk = st->to_read;
840 while ((*datalen) == 0)
841 crReturn(st->to_read);
842 if (st->chunk > (*datalen))
843 st->chunk = (*datalen);
844 memcpy(st->p, *data, st->chunk);
845 *data += st->chunk;
846 *datalen -= st->chunk;
847 st->p += st->chunk;
848 st->to_read -= st->chunk;
849 }
850
851 if (ssh->cipher && detect_attack(ssh->crcda_ctx, ssh->pktin.data,
852 st->biglen, NULL)) {
853 bombout(("Network attack (CRC compensation) detected!"));
854 crStop(0);
855 }
856
857 if (ssh->cipher)
858 ssh->cipher->decrypt(ssh->v1_cipher_ctx, ssh->pktin.data, st->biglen);
859
860 st->realcrc = crc32_compute(ssh->pktin.data, st->biglen - 4);
861 st->gotcrc = GET_32BIT(ssh->pktin.data + st->biglen - 4);
862 if (st->gotcrc != st->realcrc) {
863 bombout(("Incorrect CRC received on packet"));
864 crStop(0);
865 }
866
867 ssh->pktin.body = ssh->pktin.data + st->pad + 1;
868 ssh->pktin.savedpos = 0;
869
870 if (ssh->v1_compressing) {
871 unsigned char *decompblk;
872 int decomplen;
873 if (!zlib_decompress_block(ssh->sc_comp_ctx,
874 ssh->pktin.body - 1, ssh->pktin.length + 1,
875 &decompblk, &decomplen)) {
876 bombout(("Zlib decompression encountered invalid data"));
877 crStop(0);
878 }
879
880 if (ssh->pktin.maxlen < st->pad + decomplen) {
881 ssh->pktin.maxlen = st->pad + decomplen;
882 ssh->pktin.data = sresize(ssh->pktin.data,
883 ssh->pktin.maxlen + APIEXTRA,
884 unsigned char);
885 ssh->pktin.body = ssh->pktin.data + st->pad + 1;
886 }
887
888 memcpy(ssh->pktin.body - 1, decompblk, decomplen);
889 sfree(decompblk);
890 ssh->pktin.length = decomplen - 1;
891 }
892
893 ssh->pktin.type = ssh->pktin.body[-1];
894
895 if (ssh->logctx)
896 log_packet(ssh->logctx,
897 PKT_INCOMING, ssh->pktin.type,
898 ssh1_pkt_type(ssh->pktin.type),
899 ssh->pktin.body, ssh->pktin.length);
900
901 if (ssh->pktin.type == SSH1_SMSG_STDOUT_DATA ||
902 ssh->pktin.type == SSH1_SMSG_STDERR_DATA ||
903 ssh->pktin.type == SSH1_MSG_DEBUG ||
904 ssh->pktin.type == SSH1_SMSG_AUTH_TIS_CHALLENGE ||
905 ssh->pktin.type == SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
906 long stringlen = GET_32BIT(ssh->pktin.body);
907 if (stringlen + 4 != ssh->pktin.length) {
908 bombout(("Received data packet with bogus string length"));
909 crStop(0);
910 }
911 }
912
913 if (ssh->pktin.type == SSH1_MSG_DEBUG) {
914 /* log debug message */
915 char buf[512];
916 int stringlen = GET_32BIT(ssh->pktin.body);
917 strcpy(buf, "Remote debug message: ");
918 if (stringlen > 480)
919 stringlen = 480;
920 memcpy(buf + 8, ssh->pktin.body + 4, stringlen);
921 buf[8 + stringlen] = '\0';
922 logevent(buf);
923 goto next_packet;
924 } else if (ssh->pktin.type == SSH1_MSG_IGNORE) {
925 /* do nothing */
926 goto next_packet;
927 }
928
929 if (ssh->pktin.type == SSH1_MSG_DISCONNECT) {
930 /* log reason code in disconnect message */
931 char buf[256];
932 unsigned msglen = GET_32BIT(ssh->pktin.body);
933 unsigned nowlen;
934 strcpy(buf, "Remote sent disconnect: ");
935 nowlen = strlen(buf);
936 if (msglen > sizeof(buf) - nowlen - 1)
937 msglen = sizeof(buf) - nowlen - 1;
938 memcpy(buf + nowlen, ssh->pktin.body + 4, msglen);
939 buf[nowlen + msglen] = '\0';
940 /* logevent(buf); (this is now done within the bombout macro) */
941 bombout(("Server sent disconnect message:\n\"%s\"", buf+nowlen));
942 crStop(0);
943 }
944
945 crFinish(0);
946 }
947
948 static int ssh2_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
949 {
950 struct rdpkt2_state_tag *st = &ssh->rdpkt2_state;
951
952 crBegin(ssh->ssh2_rdpkt_crstate);
953
954 next_packet:
955 ssh->pktin.type = 0;
956 ssh->pktin.length = 0;
957 if (ssh->sccipher)
958 st->cipherblk = ssh->sccipher->blksize;
959 else
960 st->cipherblk = 8;
961 if (st->cipherblk < 8)
962 st->cipherblk = 8;
963
964 if (ssh->pktin.maxlen < st->cipherblk) {
965 ssh->pktin.maxlen = st->cipherblk;
966 ssh->pktin.data = sresize(ssh->pktin.data, st->cipherblk + APIEXTRA,
967 unsigned char);
968 }
969
970 /*
971 * Acquire and decrypt the first block of the packet. This will
972 * contain the length and padding details.
973 */
974 for (st->i = st->len = 0; st->i < st->cipherblk; st->i++) {
975 while ((*datalen) == 0)
976 crReturn(st->cipherblk - st->i);
977 ssh->pktin.data[st->i] = *(*data)++;
978 (*datalen)--;
979 }
980
981 if (ssh->sccipher)
982 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
983 ssh->pktin.data, st->cipherblk);
984
985 /*
986 * Now get the length and padding figures.
987 */
988 st->len = GET_32BIT(ssh->pktin.data);
989 st->pad = ssh->pktin.data[4];
990
991 /*
992 * _Completely_ silly lengths should be stomped on before they
993 * do us any more damage.
994 */
995 if (st->len < 0 || st->pad < 0 || st->len + st->pad < 0) {
996 bombout(("Incoming packet was garbled on decryption"));
997 crStop(0);
998 }
999
1000 /*
1001 * This enables us to deduce the payload length.
1002 */
1003 st->payload = st->len - st->pad - 1;
1004
1005 ssh->pktin.length = st->payload + 5;
1006
1007 /*
1008 * So now we can work out the total packet length.
1009 */
1010 st->packetlen = st->len + 4;
1011 st->maclen = ssh->scmac ? ssh->scmac->len : 0;
1012
1013 /*
1014 * Adjust memory allocation if packet is too big.
1015 */
1016 if (ssh->pktin.maxlen < st->packetlen + st->maclen) {
1017 ssh->pktin.maxlen = st->packetlen + st->maclen;
1018 ssh->pktin.data = sresize(ssh->pktin.data,
1019 ssh->pktin.maxlen + APIEXTRA,
1020 unsigned char);
1021 }
1022
1023 /*
1024 * Read and decrypt the remainder of the packet.
1025 */
1026 for (st->i = st->cipherblk; st->i < st->packetlen + st->maclen;
1027 st->i++) {
1028 while ((*datalen) == 0)
1029 crReturn(st->packetlen + st->maclen - st->i);
1030 ssh->pktin.data[st->i] = *(*data)++;
1031 (*datalen)--;
1032 }
1033 /* Decrypt everything _except_ the MAC. */
1034 if (ssh->sccipher)
1035 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
1036 ssh->pktin.data + st->cipherblk,
1037 st->packetlen - st->cipherblk);
1038
1039 /*
1040 * Check the MAC.
1041 */
1042 if (ssh->scmac
1043 && !ssh->scmac->verify(ssh->sc_mac_ctx, ssh->pktin.data, st->len + 4,
1044 st->incoming_sequence)) {
1045 bombout(("Incorrect MAC received on packet"));
1046 crStop(0);
1047 }
1048 st->incoming_sequence++; /* whether or not we MACed */
1049
1050 /*
1051 * Decompress packet payload.
1052 */
1053 {
1054 unsigned char *newpayload;
1055 int newlen;
1056 if (ssh->sccomp &&
1057 ssh->sccomp->decompress(ssh->sc_comp_ctx,
1058 ssh->pktin.data + 5, ssh->pktin.length - 5,
1059 &newpayload, &newlen)) {
1060 if (ssh->pktin.maxlen < newlen + 5) {
1061 ssh->pktin.maxlen = newlen + 5;
1062 ssh->pktin.data = sresize(ssh->pktin.data,
1063 ssh->pktin.maxlen + APIEXTRA,
1064 unsigned char);
1065 }
1066 ssh->pktin.length = 5 + newlen;
1067 memcpy(ssh->pktin.data + 5, newpayload, newlen);
1068 sfree(newpayload);
1069 }
1070 }
1071
1072 ssh->pktin.savedpos = 6;
1073 ssh->pktin.body = ssh->pktin.data;
1074 ssh->pktin.type = ssh->pktin.data[5];
1075
1076 if (ssh->logctx)
1077 log_packet(ssh->logctx, PKT_INCOMING, ssh->pktin.type,
1078 ssh2_pkt_type(ssh->pkt_ctx, ssh->pktin.type),
1079 ssh->pktin.data+6, ssh->pktin.length-6);
1080
1081 switch (ssh->pktin.type) {
1082 /*
1083 * These packets we must handle instantly.
1084 */
1085 case SSH2_MSG_DISCONNECT:
1086 {
1087 /* log reason code in disconnect message */
1088 char *buf;
1089 int nowlen;
1090 int reason = GET_32BIT(ssh->pktin.data + 6);
1091 unsigned msglen = GET_32BIT(ssh->pktin.data + 10);
1092
1093 if (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) {
1094 buf = dupprintf("Received disconnect message (%s)",
1095 ssh2_disconnect_reasons[reason]);
1096 } else {
1097 buf = dupprintf("Received disconnect message (unknown"
1098 " type %d)", reason);
1099 }
1100 logevent(buf);
1101 sfree(buf);
1102 buf = dupprintf("Disconnection message text: %n%.*s",
1103 &nowlen, msglen, ssh->pktin.data + 14);
1104 logevent(buf);
1105 bombout(("Server sent disconnect message\ntype %d (%s):\n\"%s\"",
1106 reason,
1107 (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) ?
1108 ssh2_disconnect_reasons[reason] : "unknown",
1109 buf+nowlen));
1110 sfree(buf);
1111 crStop(0);
1112 }
1113 break;
1114 case SSH2_MSG_IGNORE:
1115 goto next_packet;
1116 case SSH2_MSG_DEBUG:
1117 {
1118 /* log the debug message */
1119 char buf[512];
1120 /* int display = ssh->pktin.body[6]; */
1121 int stringlen = GET_32BIT(ssh->pktin.data+7);
1122 int prefix;
1123 strcpy(buf, "Remote debug message: ");
1124 prefix = strlen(buf);
1125 if (stringlen > (int)(sizeof(buf)-prefix-1))
1126 stringlen = sizeof(buf)-prefix-1;
1127 memcpy(buf + prefix, ssh->pktin.data + 11, stringlen);
1128 buf[prefix + stringlen] = '\0';
1129 logevent(buf);
1130 }
1131 goto next_packet; /* FIXME: print the debug message */
1132
1133 /*
1134 * These packets we need do nothing about here.
1135 */
1136 case SSH2_MSG_UNIMPLEMENTED:
1137 case SSH2_MSG_SERVICE_REQUEST:
1138 case SSH2_MSG_SERVICE_ACCEPT:
1139 case SSH2_MSG_KEXINIT:
1140 case SSH2_MSG_NEWKEYS:
1141 case SSH2_MSG_KEXDH_INIT:
1142 case SSH2_MSG_KEXDH_REPLY:
1143 /* case SSH2_MSG_KEX_DH_GEX_REQUEST: duplicate case value */
1144 /* case SSH2_MSG_KEX_DH_GEX_GROUP: duplicate case value */
1145 case SSH2_MSG_KEX_DH_GEX_INIT:
1146 case SSH2_MSG_KEX_DH_GEX_REPLY:
1147 case SSH2_MSG_USERAUTH_REQUEST:
1148 case SSH2_MSG_USERAUTH_FAILURE:
1149 case SSH2_MSG_USERAUTH_SUCCESS:
1150 case SSH2_MSG_USERAUTH_BANNER:
1151 case SSH2_MSG_USERAUTH_PK_OK:
1152 /* case SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ: duplicate case value */
1153 /* case SSH2_MSG_USERAUTH_INFO_REQUEST: duplicate case value */
1154 case SSH2_MSG_USERAUTH_INFO_RESPONSE:
1155 case SSH2_MSG_GLOBAL_REQUEST:
1156 case SSH2_MSG_REQUEST_SUCCESS:
1157 case SSH2_MSG_REQUEST_FAILURE:
1158 case SSH2_MSG_CHANNEL_OPEN:
1159 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION:
1160 case SSH2_MSG_CHANNEL_OPEN_FAILURE:
1161 case SSH2_MSG_CHANNEL_WINDOW_ADJUST:
1162 case SSH2_MSG_CHANNEL_DATA:
1163 case SSH2_MSG_CHANNEL_EXTENDED_DATA:
1164 case SSH2_MSG_CHANNEL_EOF:
1165 case SSH2_MSG_CHANNEL_CLOSE:
1166 case SSH2_MSG_CHANNEL_REQUEST:
1167 case SSH2_MSG_CHANNEL_SUCCESS:
1168 case SSH2_MSG_CHANNEL_FAILURE:
1169 break;
1170
1171 /*
1172 * For anything else we send SSH2_MSG_UNIMPLEMENTED.
1173 */
1174 default:
1175 ssh2_pkt_init(ssh, SSH2_MSG_UNIMPLEMENTED);
1176 ssh2_pkt_adduint32(ssh, st->incoming_sequence - 1);
1177 ssh2_pkt_send(ssh);
1178 break;
1179 }
1180
1181 crFinish(0);
1182 }
1183
1184 static void ssh1_pktout_size(Ssh ssh, int len)
1185 {
1186 int pad, biglen;
1187
1188 len += 5; /* type and CRC */
1189 pad = 8 - (len % 8);
1190 biglen = len + pad;
1191
1192 ssh->pktout.length = len - 5;
1193 if (ssh->pktout.maxlen < biglen) {
1194 ssh->pktout.maxlen = biglen;
1195 #ifdef MSCRYPTOAPI
1196 /* Allocate enough buffer space for extra block
1197 * for MS CryptEncrypt() */
1198 ssh->pktout.data = sresize(ssh->pktout.data, biglen + 12,
1199 unsigned char);
1200 #else
1201 ssh->pktout.data = sresize(ssh->pktout.data, biglen + 4,
1202 unsigned char);
1203 #endif
1204 }
1205 ssh->pktout.body = ssh->pktout.data + 4 + pad + 1;
1206 }
1207
1208 static void s_wrpkt_start(Ssh ssh, int type, int len)
1209 {
1210 ssh1_pktout_size(ssh, len);
1211 ssh->pktout.type = type;
1212 }
1213
1214 static int s_wrpkt_prepare(Ssh ssh)
1215 {
1216 int pad, biglen, i;
1217 unsigned long crc;
1218 #ifdef __SC__
1219 /*
1220 * XXX various versions of SC (including 8.8.4) screw up the
1221 * register allocation in this function and use the same register
1222 * (D6) for len and as a temporary, with predictable results. The
1223 * following sledgehammer prevents this.
1224 */
1225 volatile
1226 #endif
1227 int len;
1228
1229 ssh->pktout.body[-1] = ssh->pktout.type;
1230
1231 if (ssh->logctx)
1232 log_packet(ssh->logctx, PKT_OUTGOING, ssh->pktout.type,
1233 ssh1_pkt_type(ssh->pktout.type),
1234 ssh->pktout.body, ssh->pktout.length);
1235
1236 if (ssh->v1_compressing) {
1237 unsigned char *compblk;
1238 int complen;
1239 zlib_compress_block(ssh->cs_comp_ctx,
1240 ssh->pktout.body - 1, ssh->pktout.length + 1,
1241 &compblk, &complen);
1242 ssh1_pktout_size(ssh, complen - 1);
1243 memcpy(ssh->pktout.body - 1, compblk, complen);
1244 sfree(compblk);
1245 }
1246
1247 len = ssh->pktout.length + 5; /* type and CRC */
1248 pad = 8 - (len % 8);
1249 biglen = len + pad;
1250
1251 for (i = 0; i < pad; i++)
1252 ssh->pktout.data[i + 4] = random_byte();
1253 crc = crc32_compute(ssh->pktout.data + 4, biglen - 4);
1254 PUT_32BIT(ssh->pktout.data + biglen, crc);
1255 PUT_32BIT(ssh->pktout.data, len);
1256
1257 if (ssh->cipher)
1258 ssh->cipher->encrypt(ssh->v1_cipher_ctx, ssh->pktout.data + 4, biglen);
1259
1260 return biglen + 4;
1261 }
1262
1263 static void s_wrpkt(Ssh ssh)
1264 {
1265 int len, backlog;
1266 len = s_wrpkt_prepare(ssh);
1267 backlog = sk_write(ssh->s, (char *)ssh->pktout.data, len);
1268 if (backlog > SSH_MAX_BACKLOG)
1269 ssh_throttle_all(ssh, 1, backlog);
1270 }
1271
1272 static void s_wrpkt_defer(Ssh ssh)
1273 {
1274 int len;
1275 len = s_wrpkt_prepare(ssh);
1276 if (ssh->deferred_len + len > ssh->deferred_size) {
1277 ssh->deferred_size = ssh->deferred_len + len + 128;
1278 ssh->deferred_send_data = sresize(ssh->deferred_send_data,
1279 ssh->deferred_size,
1280 unsigned char);
1281 }
1282 memcpy(ssh->deferred_send_data + ssh->deferred_len, ssh->pktout.data, len);
1283 ssh->deferred_len += len;
1284 }
1285
1286 /*
1287 * Construct a packet with the specified contents.
1288 */
1289 static void construct_packet(Ssh ssh, int pkttype, va_list ap1, va_list ap2)
1290 {
1291 unsigned char *p, *argp, argchar;
1292 unsigned long argint;
1293 int pktlen, argtype, arglen;
1294 Bignum bn;
1295
1296 pktlen = 0;
1297 while ((argtype = va_arg(ap1, int)) != PKT_END) {
1298 switch (argtype) {
1299 case PKT_INT:
1300 (void) va_arg(ap1, int);
1301 pktlen += 4;
1302 break;
1303 case PKT_CHAR:
1304 (void) va_arg(ap1, int);
1305 pktlen++;
1306 break;
1307 case PKT_DATA:
1308 (void) va_arg(ap1, unsigned char *);
1309 arglen = va_arg(ap1, int);
1310 pktlen += arglen;
1311 break;
1312 case PKT_STR:
1313 argp = va_arg(ap1, unsigned char *);
1314 arglen = strlen((char *)argp);
1315 pktlen += 4 + arglen;
1316 break;
1317 case PKT_BIGNUM:
1318 bn = va_arg(ap1, Bignum);
1319 pktlen += ssh1_bignum_length(bn);
1320 break;
1321 default:
1322 assert(0);
1323 }
1324 }
1325
1326 s_wrpkt_start(ssh, pkttype, pktlen);
1327 p = ssh->pktout.body;
1328
1329 while ((argtype = va_arg(ap2, int)) != PKT_END) {
1330 switch (argtype) {
1331 case PKT_INT:
1332 argint = va_arg(ap2, int);
1333 PUT_32BIT(p, argint);
1334 p += 4;
1335 break;
1336 case PKT_CHAR:
1337 argchar = (unsigned char) va_arg(ap2, int);
1338 *p = argchar;
1339 p++;
1340 break;
1341 case PKT_DATA:
1342 argp = va_arg(ap2, unsigned char *);
1343 arglen = va_arg(ap2, int);
1344 memcpy(p, argp, arglen);
1345 p += arglen;
1346 break;
1347 case PKT_STR:
1348 argp = va_arg(ap2, unsigned char *);
1349 arglen = strlen((char *)argp);
1350 PUT_32BIT(p, arglen);
1351 memcpy(p + 4, argp, arglen);
1352 p += 4 + arglen;
1353 break;
1354 case PKT_BIGNUM:
1355 bn = va_arg(ap2, Bignum);
1356 p += ssh1_write_bignum(p, bn);
1357 break;
1358 }
1359 }
1360 }
1361
1362 static void send_packet(Ssh ssh, int pkttype, ...)
1363 {
1364 va_list ap1, ap2;
1365 va_start(ap1, pkttype);
1366 va_start(ap2, pkttype);
1367 construct_packet(ssh, pkttype, ap1, ap2);
1368 s_wrpkt(ssh);
1369 }
1370
1371 static void defer_packet(Ssh ssh, int pkttype, ...)
1372 {
1373 va_list ap1, ap2;
1374 va_start(ap1, pkttype);
1375 va_start(ap2, pkttype);
1376 construct_packet(ssh, pkttype, ap1, ap2);
1377 s_wrpkt_defer(ssh);
1378 }
1379
1380 static int ssh_versioncmp(char *a, char *b)
1381 {
1382 char *ae, *be;
1383 unsigned long av, bv;
1384
1385 av = strtoul(a, &ae, 10);
1386 bv = strtoul(b, &be, 10);
1387 if (av != bv)
1388 return (av < bv ? -1 : +1);
1389 if (*ae == '.')
1390 ae++;
1391 if (*be == '.')
1392 be++;
1393 av = strtoul(ae, &ae, 10);
1394 bv = strtoul(be, &be, 10);
1395 if (av != bv)
1396 return (av < bv ? -1 : +1);
1397 return 0;
1398 }
1399
1400 /*
1401 * Utility routines for putting an SSH-protocol `string' and
1402 * `uint32' into a SHA state.
1403 */
1404 #include <stdio.h>
1405 static void sha_string(SHA_State * s, void *str, int len)
1406 {
1407 unsigned char lenblk[4];
1408 PUT_32BIT(lenblk, len);
1409 SHA_Bytes(s, lenblk, 4);
1410 SHA_Bytes(s, str, len);
1411 }
1412
1413 static void sha_uint32(SHA_State * s, unsigned i)
1414 {
1415 unsigned char intblk[4];
1416 PUT_32BIT(intblk, i);
1417 SHA_Bytes(s, intblk, 4);
1418 }
1419
1420 /*
1421 * SSH2 packet construction functions.
1422 */
1423 static void ssh2_pkt_ensure(Ssh ssh, int length)
1424 {
1425 if (ssh->pktout.maxlen < length) {
1426 ssh->pktout.maxlen = length + 256;
1427 ssh->pktout.data = sresize(ssh->pktout.data,
1428 ssh->pktout.maxlen + APIEXTRA,
1429 unsigned char);
1430 if (!ssh->pktout.data)
1431 fatalbox("Out of memory");
1432 }
1433 }
1434 static void ssh2_pkt_adddata(Ssh ssh, void *data, int len)
1435 {
1436 ssh->pktout.length += len;
1437 ssh2_pkt_ensure(ssh, ssh->pktout.length);
1438 memcpy(ssh->pktout.data + ssh->pktout.length - len, data, len);
1439 }
1440 static void ssh2_pkt_addbyte(Ssh ssh, unsigned char byte)
1441 {
1442 ssh2_pkt_adddata(ssh, &byte, 1);
1443 }
1444 static void ssh2_pkt_init(Ssh ssh, int pkt_type)
1445 {
1446 ssh->pktout.length = 5;
1447 ssh2_pkt_addbyte(ssh, (unsigned char) pkt_type);
1448 }
1449 static void ssh2_pkt_addbool(Ssh ssh, unsigned char value)
1450 {
1451 ssh2_pkt_adddata(ssh, &value, 1);
1452 }
1453 static void ssh2_pkt_adduint32(Ssh ssh, unsigned long value)
1454 {
1455 unsigned char x[4];
1456 PUT_32BIT(x, value);
1457 ssh2_pkt_adddata(ssh, x, 4);
1458 }
1459 static void ssh2_pkt_addstring_start(Ssh ssh)
1460 {
1461 ssh2_pkt_adduint32(ssh, 0);
1462 ssh->pktout.savedpos = ssh->pktout.length;
1463 }
1464 static void ssh2_pkt_addstring_str(Ssh ssh, char *data)
1465 {
1466 ssh2_pkt_adddata(ssh, data, strlen(data));
1467 PUT_32BIT(ssh->pktout.data + ssh->pktout.savedpos - 4,
1468 ssh->pktout.length - ssh->pktout.savedpos);
1469 }
1470 static void ssh2_pkt_addstring_data(Ssh ssh, char *data, int len)
1471 {
1472 ssh2_pkt_adddata(ssh, data, len);
1473 PUT_32BIT(ssh->pktout.data + ssh->pktout.savedpos - 4,
1474 ssh->pktout.length - ssh->pktout.savedpos);
1475 }
1476 static void ssh2_pkt_addstring(Ssh ssh, char *data)
1477 {
1478 ssh2_pkt_addstring_start(ssh);
1479 ssh2_pkt_addstring_str(ssh, data);
1480 }
1481 static unsigned char *ssh2_mpint_fmt(Bignum b, int *len)
1482 {
1483 unsigned char *p;
1484 int i, n = (bignum_bitcount(b) + 7) / 8;
1485 p = snewn(n + 1, unsigned char);
1486 if (!p)
1487 fatalbox("out of memory");
1488 p[0] = 0;
1489 for (i = 1; i <= n; i++)
1490 p[i] = bignum_byte(b, n - i);
1491 i = 0;
1492 while (i <= n && p[i] == 0 && (p[i + 1] & 0x80) == 0)
1493 i++;
1494 memmove(p, p + i, n + 1 - i);
1495 *len = n + 1 - i;
1496 return p;
1497 }
1498 static void ssh2_pkt_addmp(Ssh ssh, Bignum b)
1499 {
1500 unsigned char *p;
1501 int len;
1502 p = ssh2_mpint_fmt(b, &len);
1503 ssh2_pkt_addstring_start(ssh);
1504 ssh2_pkt_addstring_data(ssh, (char *)p, len);
1505 sfree(p);
1506 }
1507
1508 /*
1509 * Construct an SSH2 final-form packet: compress it, encrypt it,
1510 * put the MAC on it. Final packet, ready to be sent, is stored in
1511 * ssh->pktout.data. Total length is returned.
1512 */
1513 static int ssh2_pkt_construct(Ssh ssh)
1514 {
1515 int cipherblk, maclen, padding, i;
1516
1517 if (ssh->logctx)
1518 log_packet(ssh->logctx, PKT_OUTGOING, ssh->pktout.data[5],
1519 ssh2_pkt_type(ssh->pkt_ctx, ssh->pktout.data[5]),
1520 ssh->pktout.data + 6, ssh->pktout.length - 6);
1521
1522 /*
1523 * Compress packet payload.
1524 */
1525 {
1526 unsigned char *newpayload;
1527 int newlen;
1528 if (ssh->cscomp &&
1529 ssh->cscomp->compress(ssh->cs_comp_ctx, ssh->pktout.data + 5,
1530 ssh->pktout.length - 5,
1531 &newpayload, &newlen)) {
1532 ssh->pktout.length = 5;
1533 ssh2_pkt_adddata(ssh, newpayload, newlen);
1534 sfree(newpayload);
1535 }
1536 }
1537
1538 /*
1539 * Add padding. At least four bytes, and must also bring total
1540 * length (minus MAC) up to a multiple of the block size.
1541 */
1542 cipherblk = ssh->cscipher ? ssh->cscipher->blksize : 8; /* block size */
1543 cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */
1544 padding = 4;
1545 padding +=
1546 (cipherblk - (ssh->pktout.length + padding) % cipherblk) % cipherblk;
1547 maclen = ssh->csmac ? ssh->csmac->len : 0;
1548 ssh2_pkt_ensure(ssh, ssh->pktout.length + padding + maclen);
1549 ssh->pktout.data[4] = padding;
1550 for (i = 0; i < padding; i++)
1551 ssh->pktout.data[ssh->pktout.length + i] = random_byte();
1552 PUT_32BIT(ssh->pktout.data, ssh->pktout.length + padding - 4);
1553 if (ssh->csmac)
1554 ssh->csmac->generate(ssh->cs_mac_ctx, ssh->pktout.data,
1555 ssh->pktout.length + padding,
1556 ssh->v2_outgoing_sequence);
1557 ssh->v2_outgoing_sequence++; /* whether or not we MACed */
1558
1559 if (ssh->cscipher)
1560 ssh->cscipher->encrypt(ssh->cs_cipher_ctx,
1561 ssh->pktout.data, ssh->pktout.length + padding);
1562
1563 /* Ready-to-send packet starts at ssh->pktout.data. We return length. */
1564 return ssh->pktout.length + padding + maclen;
1565 }
1566
1567 /*
1568 * Construct and send an SSH2 packet immediately.
1569 */
1570 static void ssh2_pkt_send(Ssh ssh)
1571 {
1572 int len;
1573 int backlog;
1574 len = ssh2_pkt_construct(ssh);
1575 backlog = sk_write(ssh->s, (char *)ssh->pktout.data, len);
1576 if (backlog > SSH_MAX_BACKLOG)
1577 ssh_throttle_all(ssh, 1, backlog);
1578 }
1579
1580 /*
1581 * Construct an SSH2 packet and add it to a deferred data block.
1582 * Useful for sending multiple packets in a single sk_write() call,
1583 * to prevent a traffic-analysing listener from being able to work
1584 * out the length of any particular packet (such as the password
1585 * packet).
1586 *
1587 * Note that because SSH2 sequence-numbers its packets, this can
1588 * NOT be used as an m4-style `defer' allowing packets to be
1589 * constructed in one order and sent in another.
1590 */
1591 static void ssh2_pkt_defer(Ssh ssh)
1592 {
1593 int len = ssh2_pkt_construct(ssh);
1594 if (ssh->deferred_len + len > ssh->deferred_size) {
1595 ssh->deferred_size = ssh->deferred_len + len + 128;
1596 ssh->deferred_send_data = sresize(ssh->deferred_send_data,
1597 ssh->deferred_size,
1598 unsigned char);
1599 }
1600 memcpy(ssh->deferred_send_data + ssh->deferred_len, ssh->pktout.data, len);
1601 ssh->deferred_len += len;
1602 }
1603
1604 /*
1605 * Send the whole deferred data block constructed by
1606 * ssh2_pkt_defer() or SSH1's defer_packet().
1607 */
1608 static void ssh_pkt_defersend(Ssh ssh)
1609 {
1610 int backlog;
1611 backlog = sk_write(ssh->s, (char *)ssh->deferred_send_data,
1612 ssh->deferred_len);
1613 ssh->deferred_len = ssh->deferred_size = 0;
1614 sfree(ssh->deferred_send_data);
1615 ssh->deferred_send_data = NULL;
1616 if (backlog > SSH_MAX_BACKLOG)
1617 ssh_throttle_all(ssh, 1, backlog);
1618 }
1619
1620 #if 0
1621 void bndebug(char *string, Bignum b)
1622 {
1623 unsigned char *p;
1624 int i, len;
1625 p = ssh2_mpint_fmt(b, &len);
1626 debug(("%s", string));
1627 for (i = 0; i < len; i++)
1628 debug((" %02x", p[i]));
1629 debug(("\n"));
1630 sfree(p);
1631 }
1632 #endif
1633
1634 static void sha_mpint(SHA_State * s, Bignum b)
1635 {
1636 unsigned char *p;
1637 int len;
1638 p = ssh2_mpint_fmt(b, &len);
1639 sha_string(s, p, len);
1640 sfree(p);
1641 }
1642
1643 /*
1644 * Packet decode functions for both SSH1 and SSH2.
1645 */
1646 static unsigned long ssh_pkt_getuint32(Ssh ssh)
1647 {
1648 unsigned long value;
1649 if (ssh->pktin.length - ssh->pktin.savedpos < 4)
1650 return 0; /* arrgh, no way to decline (FIXME?) */
1651 value = GET_32BIT(ssh->pktin.body + ssh->pktin.savedpos);
1652 ssh->pktin.savedpos += 4;
1653 return value;
1654 }
1655 static int ssh2_pkt_getbool(Ssh ssh)
1656 {
1657 unsigned long value;
1658 if (ssh->pktin.length - ssh->pktin.savedpos < 1)
1659 return 0; /* arrgh, no way to decline (FIXME?) */
1660 value = ssh->pktin.body[ssh->pktin.savedpos] != 0;
1661 ssh->pktin.savedpos++;
1662 return value;
1663 }
1664 static void ssh_pkt_getstring(Ssh ssh, char **p, int *length)
1665 {
1666 int len;
1667 *p = NULL;
1668 *length = 0;
1669 if (ssh->pktin.length - ssh->pktin.savedpos < 4)
1670 return;
1671 len = GET_32BIT(ssh->pktin.body + ssh->pktin.savedpos);
1672 if (len < 0)
1673 return;
1674 *length = len;
1675 ssh->pktin.savedpos += 4;
1676 if (ssh->pktin.length - ssh->pktin.savedpos < *length)
1677 return;
1678 *p = (char *)(ssh->pktin.body + ssh->pktin.savedpos);
1679 ssh->pktin.savedpos += *length;
1680 }
1681 static void *ssh_pkt_getdata(Ssh ssh, int length)
1682 {
1683 if (ssh->pktin.length - ssh->pktin.savedpos < length)
1684 return NULL;
1685 ssh->pktin.savedpos += length;
1686 return ssh->pktin.body + (ssh->pktin.savedpos - length);
1687 }
1688 static int ssh1_pkt_getrsakey(Ssh ssh, struct RSAKey *key,
1689 unsigned char **keystr)
1690 {
1691 int j;
1692
1693 j = makekey(ssh->pktin.body + ssh->pktin.savedpos,
1694 ssh->pktin.length - ssh->pktin.savedpos,
1695 key, keystr, 0);
1696
1697 if (j < 0)
1698 return FALSE;
1699
1700 ssh->pktin.savedpos += j;
1701 assert(ssh->pktin.savedpos < ssh->pktin.length);
1702
1703 return TRUE;
1704 }
1705 static Bignum ssh1_pkt_getmp(Ssh ssh)
1706 {
1707 int j;
1708 Bignum b;
1709
1710 j = ssh1_read_bignum(ssh->pktin.body + ssh->pktin.savedpos,
1711 ssh->pktin.length - ssh->pktin.savedpos, &b);
1712
1713 if (j < 0)
1714 return NULL;
1715
1716 ssh->pktin.savedpos += j;
1717 return b;
1718 }
1719 static Bignum ssh2_pkt_getmp(Ssh ssh)
1720 {
1721 char *p;
1722 int length;
1723 Bignum b;
1724
1725 ssh_pkt_getstring(ssh, &p, &length);
1726 if (!p)
1727 return NULL;
1728 if (p[0] & 0x80) {
1729 bombout(("internal error: Can't handle negative mpints"));
1730 return NULL;
1731 }
1732 b = bignum_from_bytes((unsigned char *)p, length);
1733 return b;
1734 }
1735
1736 /*
1737 * Helper function to add an SSH2 signature blob to a packet.
1738 * Expects to be shown the public key blob as well as the signature
1739 * blob. Normally works just like ssh2_pkt_addstring, but will
1740 * fiddle with the signature packet if necessary for
1741 * BUG_SSH2_RSA_PADDING.
1742 */
1743 static void ssh2_add_sigblob(Ssh ssh, void *pkblob_v, int pkblob_len,
1744 void *sigblob_v, int sigblob_len)
1745 {
1746 unsigned char *pkblob = (unsigned char *)pkblob_v;
1747 unsigned char *sigblob = (unsigned char *)sigblob_v;
1748
1749 /* dmemdump(pkblob, pkblob_len); */
1750 /* dmemdump(sigblob, sigblob_len); */
1751
1752 /*
1753 * See if this is in fact an ssh-rsa signature and a buggy
1754 * server; otherwise we can just do this the easy way.
1755 */
1756 if ((ssh->remote_bugs & BUG_SSH2_RSA_PADDING) &&
1757 (GET_32BIT(pkblob) == 7 && !memcmp(pkblob+4, "ssh-rsa", 7))) {
1758 int pos, len, siglen;
1759
1760 /*
1761 * Find the byte length of the modulus.
1762 */
1763
1764 pos = 4+7; /* skip over "ssh-rsa" */
1765 pos += 4 + GET_32BIT(pkblob+pos); /* skip over exponent */
1766 len = GET_32BIT(pkblob+pos); /* find length of modulus */
1767 pos += 4; /* find modulus itself */
1768 while (len > 0 && pkblob[pos] == 0)
1769 len--, pos++;
1770 /* debug(("modulus length is %d\n", len)); */
1771
1772 /*
1773 * Now find the signature integer.
1774 */
1775 pos = 4+7; /* skip over "ssh-rsa" */
1776 siglen = GET_32BIT(sigblob+pos);
1777 /* debug(("signature length is %d\n", siglen)); */
1778
1779 if (len != siglen) {
1780 unsigned char newlen[4];
1781 ssh2_pkt_addstring_start(ssh);
1782 ssh2_pkt_addstring_data(ssh, (char *)sigblob, pos);
1783 /* dmemdump(sigblob, pos); */
1784 pos += 4; /* point to start of actual sig */
1785 PUT_32BIT(newlen, len);
1786 ssh2_pkt_addstring_data(ssh, (char *)newlen, 4);
1787 /* dmemdump(newlen, 4); */
1788 newlen[0] = 0;
1789 while (len-- > siglen) {
1790 ssh2_pkt_addstring_data(ssh, (char *)newlen, 1);
1791 /* dmemdump(newlen, 1); */
1792 }
1793 ssh2_pkt_addstring_data(ssh, (char *)(sigblob+pos), siglen);
1794 /* dmemdump(sigblob+pos, siglen); */
1795 return;
1796 }
1797
1798 /* Otherwise fall through and do it the easy way. */
1799 }
1800
1801 ssh2_pkt_addstring_start(ssh);
1802 ssh2_pkt_addstring_data(ssh, (char *)sigblob, sigblob_len);
1803 }
1804
1805 /*
1806 * Examine the remote side's version string and compare it against
1807 * a list of known buggy implementations.
1808 */
1809 static void ssh_detect_bugs(Ssh ssh, char *vstring)
1810 {
1811 char *imp; /* pointer to implementation part */
1812 imp = vstring;
1813 imp += strcspn(imp, "-");
1814 if (*imp) imp++;
1815 imp += strcspn(imp, "-");
1816 if (*imp) imp++;
1817
1818 ssh->remote_bugs = 0;
1819
1820 if (ssh->cfg.sshbug_ignore1 == FORCE_ON ||
1821 (ssh->cfg.sshbug_ignore1 == AUTO &&
1822 (!strcmp(imp, "1.2.18") || !strcmp(imp, "1.2.19") ||
1823 !strcmp(imp, "1.2.20") || !strcmp(imp, "1.2.21") ||
1824 !strcmp(imp, "1.2.22") || !strcmp(imp, "Cisco-1.25") ||
1825 !strcmp(imp, "OSU_1.4alpha3")))) {
1826 /*
1827 * These versions don't support SSH1_MSG_IGNORE, so we have
1828 * to use a different defence against password length
1829 * sniffing.
1830 */
1831 ssh->remote_bugs |= BUG_CHOKES_ON_SSH1_IGNORE;
1832 logevent("We believe remote version has SSH1 ignore bug");
1833 }
1834
1835 if (ssh->cfg.sshbug_plainpw1 == FORCE_ON ||
1836 (ssh->cfg.sshbug_plainpw1 == AUTO &&
1837 (!strcmp(imp, "Cisco-1.25") || !strcmp(imp, "OSU_1.4alpha3")))) {
1838 /*
1839 * These versions need a plain password sent; they can't
1840 * handle having a null and a random length of data after
1841 * the password.
1842 */
1843 ssh->remote_bugs |= BUG_NEEDS_SSH1_PLAIN_PASSWORD;
1844 logevent("We believe remote version needs a plain SSH1 password");
1845 }
1846
1847 if (ssh->cfg.sshbug_rsa1 == FORCE_ON ||
1848 (ssh->cfg.sshbug_rsa1 == AUTO &&
1849 (!strcmp(imp, "Cisco-1.25")))) {
1850 /*
1851 * These versions apparently have no clue whatever about
1852 * RSA authentication and will panic and die if they see
1853 * an AUTH_RSA message.
1854 */
1855 ssh->remote_bugs |= BUG_CHOKES_ON_RSA;
1856 logevent("We believe remote version can't handle RSA authentication");
1857 }
1858
1859 if (ssh->cfg.sshbug_hmac2 == FORCE_ON ||
1860 (ssh->cfg.sshbug_hmac2 == AUTO &&
1861 !wc_match("* VShell", imp) &&
1862 (wc_match("2.1.0*", imp) || wc_match("2.0.*", imp) ||
1863 wc_match("2.2.0*", imp) || wc_match("2.3.0*", imp) ||
1864 wc_match("2.1 *", imp)))) {
1865 /*
1866 * These versions have the HMAC bug.
1867 */
1868 ssh->remote_bugs |= BUG_SSH2_HMAC;
1869 logevent("We believe remote version has SSH2 HMAC bug");
1870 }
1871
1872 if (ssh->cfg.sshbug_derivekey2 == FORCE_ON ||
1873 (ssh->cfg.sshbug_derivekey2 == AUTO &&
1874 !wc_match("* VShell", imp) &&
1875 (wc_match("2.0.0*", imp) || wc_match("2.0.10*", imp) ))) {
1876 /*
1877 * These versions have the key-derivation bug (failing to
1878 * include the literal shared secret in the hashes that
1879 * generate the keys).
1880 */
1881 ssh->remote_bugs |= BUG_SSH2_DERIVEKEY;
1882 logevent("We believe remote version has SSH2 key-derivation bug");
1883 }
1884
1885 if (ssh->cfg.sshbug_rsapad2 == FORCE_ON ||
1886 (ssh->cfg.sshbug_rsapad2 == AUTO &&
1887 (wc_match("OpenSSH_2.[5-9]*", imp) ||
1888 wc_match("OpenSSH_3.[0-2]*", imp)))) {
1889 /*
1890 * These versions have the SSH2 RSA padding bug.
1891 */
1892 ssh->remote_bugs |= BUG_SSH2_RSA_PADDING;
1893 logevent("We believe remote version has SSH2 RSA padding bug");
1894 }
1895
1896 if (ssh->cfg.sshbug_pksessid2 == FORCE_ON ||
1897 (ssh->cfg.sshbug_pksessid2 == AUTO &&
1898 wc_match("OpenSSH_2.[0-2]*", imp))) {
1899 /*
1900 * These versions have the SSH2 session-ID bug in
1901 * public-key authentication.
1902 */
1903 ssh->remote_bugs |= BUG_SSH2_PK_SESSIONID;
1904 logevent("We believe remote version has SSH2 public-key-session-ID bug");
1905 }
1906
1907 if (ssh->cfg.sshbug_dhgex2 == FORCE_ON) {
1908 /*
1909 * User specified the SSH2 DH GEX bug.
1910 */
1911 ssh->remote_bugs |= BUG_SSH2_DH_GEX;
1912 logevent("We believe remote version has SSH2 DH group exchange bug");
1913 }
1914 }
1915
1916 static int do_ssh_init(Ssh ssh, unsigned char c)
1917 {
1918 struct do_ssh_init_state {
1919 int vslen;
1920 char version[10];
1921 char *vstring;
1922 int vstrsize;
1923 int i;
1924 int proto1, proto2;
1925 };
1926 crState(do_ssh_init_state);
1927
1928 crBegin(ssh->do_ssh_init_crstate);
1929
1930 /* Search for the string "SSH-" in the input. */
1931 s->i = 0;
1932 while (1) {
1933 static const int transS[] = { 1, 2, 2, 1 };
1934 static const int transH[] = { 0, 0, 3, 0 };
1935 static const int transminus[] = { 0, 0, 0, -1 };
1936 if (c == 'S')
1937 s->i = transS[s->i];
1938 else if (c == 'H')
1939 s->i = transH[s->i];
1940 else if (c == '-')
1941 s->i = transminus[s->i];
1942 else
1943 s->i = 0;
1944 if (s->i < 0)
1945 break;
1946 crReturn(1); /* get another character */
1947 }
1948
1949 s->vstrsize = 16;
1950 s->vstring = snewn(s->vstrsize, char);
1951 strcpy(s->vstring, "SSH-");
1952 s->vslen = 4;
1953 s->i = 0;
1954 while (1) {
1955 crReturn(1); /* get another char */
1956 if (s->vslen >= s->vstrsize - 1) {
1957 s->vstrsize += 16;
1958 s->vstring = sresize(s->vstring, s->vstrsize, char);
1959 }
1960 s->vstring[s->vslen++] = c;
1961 if (s->i >= 0) {
1962 if (c == '-') {
1963 s->version[s->i] = '\0';
1964 s->i = -1;
1965 } else if (s->i < sizeof(s->version) - 1)
1966 s->version[s->i++] = c;
1967 } else if (c == '\012')
1968 break;
1969 }
1970
1971 ssh->agentfwd_enabled = FALSE;
1972 ssh->rdpkt2_state.incoming_sequence = 0;
1973
1974 s->vstring[s->vslen] = 0;
1975 s->vstring[strcspn(s->vstring, "\r\n")] = '\0';/* remove EOL chars */
1976 {
1977 char *vlog;
1978 vlog = snewn(20 + s->vslen, char);
1979 sprintf(vlog, "Server version: %s", s->vstring);
1980 logevent(vlog);
1981 sfree(vlog);
1982 }
1983 ssh_detect_bugs(ssh, s->vstring);
1984
1985 /*
1986 * Decide which SSH protocol version to support.
1987 */
1988
1989 /* Anything strictly below "2.0" means protocol 1 is supported. */
1990 s->proto1 = ssh_versioncmp(s->version, "2.0") < 0;
1991 /* Anything greater or equal to "1.99" means protocol 2 is supported. */
1992 s->proto2 = ssh_versioncmp(s->version, "1.99") >= 0;
1993
1994 if (ssh->cfg.sshprot == 0 && !s->proto1) {
1995 bombout(("SSH protocol version 1 required by user but not provided by server"));
1996 crStop(0);
1997 }
1998 if (ssh->cfg.sshprot == 3 && !s->proto2) {
1999 bombout(("SSH protocol version 2 required by user but not provided by server"));
2000 crStop(0);
2001 }
2002
2003 if (s->proto2 && (ssh->cfg.sshprot >= 2 || !s->proto1)) {
2004 /*
2005 * Use v2 protocol.
2006 */
2007 char verstring[80], vlog[100];
2008 sprintf(verstring, "SSH-2.0-%s", sshver);
2009 SHA_Init(&ssh->exhashbase);
2010 /*
2011 * Hash our version string and their version string.
2012 */
2013 sha_string(&ssh->exhashbase, verstring, strlen(verstring));
2014 sha_string(&ssh->exhashbase, s->vstring, strcspn(s->vstring, "\r\n"));
2015 sprintf(vlog, "We claim version: %s", verstring);
2016 logevent(vlog);
2017 strcat(verstring, "\012");
2018 logevent("Using SSH protocol version 2");
2019 sk_write(ssh->s, verstring, strlen(verstring));
2020 ssh->protocol = ssh2_protocol;
2021 ssh->version = 2;
2022 ssh->s_rdpkt = ssh2_rdpkt;
2023 } else {
2024 /*
2025 * Use v1 protocol.
2026 */
2027 char verstring[80], vlog[100];
2028 sprintf(verstring, "SSH-%s-%s",
2029 (ssh_versioncmp(s->version, "1.5") <= 0 ? s->version : "1.5"),
2030 sshver);
2031 sprintf(vlog, "We claim version: %s", verstring);
2032 logevent(vlog);
2033 strcat(verstring, "\012");
2034
2035 logevent("Using SSH protocol version 1");
2036 sk_write(ssh->s, verstring, strlen(verstring));
2037 ssh->protocol = ssh1_protocol;
2038 ssh->version = 1;
2039 ssh->s_rdpkt = ssh1_rdpkt;
2040 }
2041 update_specials_menu(ssh->frontend);
2042 ssh->state = SSH_STATE_BEFORE_SIZE;
2043
2044 sfree(s->vstring);
2045
2046 crFinish(0);
2047 }
2048
2049 static void ssh_gotdata(Ssh ssh, unsigned char *data, int datalen)
2050 {
2051 crBegin(ssh->ssh_gotdata_crstate);
2052
2053 /*
2054 * To begin with, feed the characters one by one to the
2055 * protocol initialisation / selection function do_ssh_init().
2056 * When that returns 0, we're done with the initial greeting
2057 * exchange and can move on to packet discipline.
2058 */
2059 while (1) {
2060 int ret; /* need not be kept across crReturn */
2061 if (datalen == 0)
2062 crReturnV; /* more data please */
2063 ret = do_ssh_init(ssh, *data);
2064 data++;
2065 datalen--;
2066 if (ret == 0)
2067 break;
2068 }
2069
2070 /*
2071 * We emerge from that loop when the initial negotiation is
2072 * over and we have selected an s_rdpkt function. Now pass
2073 * everything to s_rdpkt, and then pass the resulting packets
2074 * to the proper protocol handler.
2075 */
2076 if (datalen == 0)
2077 crReturnV;
2078 while (1) {
2079 while (datalen > 0) {
2080 if (ssh->s_rdpkt(ssh, &data, &datalen) == 0) {
2081 if (ssh->state == SSH_STATE_CLOSED) {
2082 return;
2083 }
2084 ssh->protocol(ssh, NULL, 0, 1);
2085 if (ssh->state == SSH_STATE_CLOSED) {
2086 return;
2087 }
2088 }
2089 }
2090 crReturnV;
2091 }
2092 crFinishV;
2093 }
2094
2095 static void ssh_do_close(Ssh ssh)
2096 {
2097 int i;
2098 struct ssh_channel *c;
2099
2100 ssh->state = SSH_STATE_CLOSED;
2101 if (ssh->s) {
2102 sk_close(ssh->s);
2103 ssh->s = NULL;
2104 }
2105 /*
2106 * Now we must shut down any port and X forwardings going
2107 * through this connection.
2108 */
2109 if (ssh->channels) {
2110 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
2111 switch (c->type) {
2112 case CHAN_X11:
2113 x11_close(c->u.x11.s);
2114 break;
2115 case CHAN_SOCKDATA:
2116 pfd_close(c->u.pfd.s);
2117 break;
2118 }
2119 del234(ssh->channels, c);
2120 if (ssh->version == 2)
2121 bufchain_clear(&c->v.v2.outbuffer);
2122 sfree(c);
2123 }
2124 }
2125 }
2126
2127 static int ssh_closing(Plug plug, const char *error_msg, int error_code,
2128 int calling_back)
2129 {
2130 Ssh ssh = (Ssh) plug;
2131 ssh_do_close(ssh);
2132 if (error_msg) {
2133 /* A socket error has occurred. */
2134 logevent(error_msg);
2135 connection_fatal(ssh->frontend, "%s", error_msg);
2136 } else {
2137 /* Otherwise, the remote side closed the connection normally. */
2138 }
2139 return 0;
2140 }
2141
2142 static int ssh_receive(Plug plug, int urgent, char *data, int len)
2143 {
2144 Ssh ssh = (Ssh) plug;
2145 ssh_gotdata(ssh, (unsigned char *)data, len);
2146 if (ssh->state == SSH_STATE_CLOSED) {
2147 ssh_do_close(ssh);
2148 return 0;
2149 }
2150 return 1;
2151 }
2152
2153 static void ssh_sent(Plug plug, int bufsize)
2154 {
2155 Ssh ssh = (Ssh) plug;
2156 /*
2157 * If the send backlog on the SSH socket itself clears, we
2158 * should unthrottle the whole world if it was throttled.
2159 */
2160 if (bufsize < SSH_MAX_BACKLOG)
2161 ssh_throttle_all(ssh, 0, bufsize);
2162 }
2163
2164 /*
2165 * Connect to specified host and port.
2166 * Returns an error message, or NULL on success.
2167 * Also places the canonical host name into `realhost'. It must be
2168 * freed by the caller.
2169 */
2170 static const char *connect_to_host(Ssh ssh, char *host, int port,
2171 char **realhost, int nodelay, int keepalive)
2172 {
2173 static const struct plug_function_table fn_table = {
2174 ssh_closing,
2175 ssh_receive,
2176 ssh_sent,
2177 NULL
2178 };
2179
2180 SockAddr addr;
2181 const char *err;
2182
2183 ssh->savedhost = snewn(1 + strlen(host), char);
2184 if (!ssh->savedhost)
2185 fatalbox("Out of memory");
2186 strcpy(ssh->savedhost, host);
2187
2188 if (port < 0)
2189 port = 22; /* default ssh port */
2190 ssh->savedport = port;
2191
2192 /*
2193 * Try to find host.
2194 */
2195 logeventf(ssh, "Looking up host \"%s\"", host);
2196 addr = name_lookup(host, port, realhost, &ssh->cfg);
2197 if ((err = sk_addr_error(addr)) != NULL) {
2198 sk_addr_free(addr);
2199 return err;
2200 }
2201
2202 /*
2203 * Open socket.
2204 */
2205 {
2206 char addrbuf[100];
2207 sk_getaddr(addr, addrbuf, 100);
2208 logeventf(ssh, "Connecting to %s port %d", addrbuf, port);
2209 }
2210 ssh->fn = &fn_table;
2211 ssh->s = new_connection(addr, *realhost, port,
2212 0, 1, nodelay, keepalive, (Plug) ssh, &ssh->cfg);
2213 if ((err = sk_socket_error(ssh->s)) != NULL) {
2214 ssh->s = NULL;
2215 return err;
2216 }
2217
2218 return NULL;
2219 }
2220
2221 /*
2222 * Throttle or unthrottle the SSH connection.
2223 */
2224 static void ssh1_throttle(Ssh ssh, int adjust)
2225 {
2226 int old_count = ssh->v1_throttle_count;
2227 ssh->v1_throttle_count += adjust;
2228 assert(ssh->v1_throttle_count >= 0);
2229 if (ssh->v1_throttle_count && !old_count) {
2230 sk_set_frozen(ssh->s, 1);
2231 } else if (!ssh->v1_throttle_count && old_count) {
2232 sk_set_frozen(ssh->s, 0);
2233 }
2234 }
2235
2236 /*
2237 * Throttle or unthrottle _all_ local data streams (for when sends
2238 * on the SSH connection itself back up).
2239 */
2240 static void ssh_throttle_all(Ssh ssh, int enable, int bufsize)
2241 {
2242 int i;
2243 struct ssh_channel *c;
2244
2245 if (enable == ssh->throttled_all)
2246 return;
2247 ssh->throttled_all = enable;
2248 ssh->overall_bufsize = bufsize;
2249 if (!ssh->channels)
2250 return;
2251 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
2252 switch (c->type) {
2253 case CHAN_MAINSESSION:
2254 /*
2255 * This is treated separately, outside the switch.
2256 */
2257 break;
2258 case CHAN_X11:
2259 x11_override_throttle(c->u.x11.s, enable);
2260 break;
2261 case CHAN_AGENT:
2262 /* Agent channels require no buffer management. */
2263 break;
2264 case CHAN_SOCKDATA:
2265 pfd_override_throttle(c->u.pfd.s, enable);
2266 break;
2267 }
2268 }
2269 }
2270
2271 /*
2272 * Username and password input, abstracted off into routines
2273 * reusable in several places - even between SSH1 and SSH2.
2274 */
2275
2276 /* Set up a username or password input loop on a given buffer. */
2277 static void setup_userpass_input(Ssh ssh, char *buffer, int buflen, int echo)
2278 {
2279 ssh->userpass_input_buffer = buffer;
2280 ssh->userpass_input_buflen = buflen;
2281 ssh->userpass_input_bufpos = 0;
2282 ssh->userpass_input_echo = echo;
2283 }
2284
2285 /*
2286 * Process some terminal data in the course of username/password
2287 * input. Returns >0 for success (line of input returned in
2288 * buffer), <0 for failure (user hit ^C/^D, bomb out and exit), 0
2289 * for inconclusive (keep waiting for more input please).
2290 */
2291 static int process_userpass_input(Ssh ssh, unsigned char *in, int inlen)
2292 {
2293 char c;
2294
2295 while (inlen--) {
2296 switch (c = *in++) {
2297 case 10:
2298 case 13:
2299 ssh->userpass_input_buffer[ssh->userpass_input_bufpos] = 0;
2300 ssh->userpass_input_buffer[ssh->userpass_input_buflen-1] = 0;
2301 return +1;
2302 break;
2303 case 8:
2304 case 127:
2305 if (ssh->userpass_input_bufpos > 0) {
2306 if (ssh->userpass_input_echo)
2307 c_write_str(ssh, "\b \b");
2308 ssh->userpass_input_bufpos--;
2309 }
2310 break;
2311 case 21:
2312 case 27:
2313 while (ssh->userpass_input_bufpos > 0) {
2314 if (ssh->userpass_input_echo)
2315 c_write_str(ssh, "\b \b");
2316 ssh->userpass_input_bufpos--;
2317 }
2318 break;
2319 case 3:
2320 case 4:
2321 return -1;
2322 break;
2323 default:
2324 /*
2325 * This simplistic check for printability is disabled
2326 * when we're doing password input, because some people
2327 * have control characters in their passwords.o
2328 */
2329 if ((!ssh->userpass_input_echo ||
2330 (c >= ' ' && c <= '~') ||
2331 ((unsigned char) c >= 160))
2332 && ssh->userpass_input_bufpos < ssh->userpass_input_buflen-1) {
2333 ssh->userpass_input_buffer[ssh->userpass_input_bufpos++] = c;
2334 if (ssh->userpass_input_echo)
2335 c_write(ssh, &c, 1);
2336 }
2337 break;
2338 }
2339 }
2340 return 0;
2341 }
2342
2343 static void ssh_agent_callback(void *sshv, void *reply, int replylen)
2344 {
2345 Ssh ssh = (Ssh) sshv;
2346
2347 ssh->agent_response = reply;
2348 ssh->agent_response_len = replylen;
2349
2350 if (ssh->version == 1)
2351 do_ssh1_login(ssh, NULL, -1, 0);
2352 else
2353 do_ssh2_authconn(ssh, NULL, -1, 0);
2354 }
2355
2356 static void ssh_agentf_callback(void *cv, void *reply, int replylen)
2357 {
2358 struct ssh_channel *c = (struct ssh_channel *)cv;
2359 Ssh ssh = c->ssh;
2360 void *sentreply = reply;
2361
2362 if (!sentreply) {
2363 /* Fake SSH_AGENT_FAILURE. */
2364 sentreply = "\0\0\0\1\5";
2365 replylen = 5;
2366 }
2367 if (ssh->version == 2) {
2368 ssh2_add_channel_data(c, sentreply, replylen);
2369 ssh2_try_send(c);
2370 } else {
2371 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
2372 PKT_INT, c->remoteid,
2373 PKT_INT, replylen,
2374 PKT_DATA, sentreply, replylen,
2375 PKT_END);
2376 }
2377 if (reply)
2378 sfree(reply);
2379 }
2380
2381 /*
2382 * Handle the key exchange and user authentication phases.
2383 */
2384 static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
2385 {
2386 int i, j, ret;
2387 unsigned char cookie[8], *ptr;
2388 struct RSAKey servkey, hostkey;
2389 struct MD5Context md5c;
2390 struct do_ssh1_login_state {
2391 int len;
2392 unsigned char *rsabuf, *keystr1, *keystr2;
2393 unsigned long supported_ciphers_mask, supported_auths_mask;
2394 int tried_publickey, tried_agent;
2395 int tis_auth_refused, ccard_auth_refused;
2396 unsigned char session_id[16];
2397 int cipher_type;
2398 char username[100];
2399 void *publickey_blob;
2400 int publickey_bloblen;
2401 char password[100];
2402 char prompt[200];
2403 int pos;
2404 char c;
2405 int pwpkt_type;
2406 unsigned char request[5], *response, *p;
2407 int responselen;
2408 int keyi, nkeys;
2409 int authed;
2410 struct RSAKey key;
2411 Bignum challenge;
2412 char *commentp;
2413 int commentlen;
2414 };
2415 crState(do_ssh1_login_state);
2416
2417 crBegin(ssh->do_ssh1_login_crstate);
2418
2419 if (!ispkt)
2420 crWaitUntil(ispkt);
2421
2422 if (ssh->pktin.type != SSH1_SMSG_PUBLIC_KEY) {
2423 bombout(("Public key packet not received"));
2424 crStop(0);
2425 }
2426
2427 logevent("Received public keys");
2428
2429 ptr = ssh_pkt_getdata(ssh, 8);
2430 if (!ptr) {
2431 bombout(("SSH1 public key packet stopped before random cookie"));
2432 crStop(0);
2433 }
2434 memcpy(cookie, ptr, 8);
2435
2436 if (!ssh1_pkt_getrsakey(ssh, &servkey, &s->keystr1) ||
2437 !ssh1_pkt_getrsakey(ssh, &hostkey, &s->keystr2)) {
2438 bombout(("SSH1 public key packet stopped before public keys"));
2439 crStop(0);
2440 }
2441
2442 /*
2443 * Log the host key fingerprint.
2444 */
2445 {
2446 char logmsg[80];
2447 logevent("Host key fingerprint is:");
2448 strcpy(logmsg, " ");
2449 hostkey.comment = NULL;
2450 rsa_fingerprint(logmsg + strlen(logmsg),
2451 sizeof(logmsg) - strlen(logmsg), &hostkey);
2452 logevent(logmsg);
2453 }
2454
2455 ssh->v1_remote_protoflags = ssh_pkt_getuint32(ssh);
2456 s->supported_ciphers_mask = ssh_pkt_getuint32(ssh);
2457 s->supported_auths_mask = ssh_pkt_getuint32(ssh);
2458
2459 ssh->v1_local_protoflags =
2460 ssh->v1_remote_protoflags & SSH1_PROTOFLAGS_SUPPORTED;
2461 ssh->v1_local_protoflags |= SSH1_PROTOFLAG_SCREEN_NUMBER;
2462
2463 MD5Init(&md5c);
2464 MD5Update(&md5c, s->keystr2, hostkey.bytes);
2465 MD5Update(&md5c, s->keystr1, servkey.bytes);
2466 MD5Update(&md5c, cookie, 8);
2467 MD5Final(s->session_id, &md5c);
2468
2469 for (i = 0; i < 32; i++)
2470 ssh->session_key[i] = random_byte();
2471
2472 /*
2473 * Verify that the `bits' and `bytes' parameters match.
2474 */
2475 if (hostkey.bits > hostkey.bytes * 8 ||
2476 servkey.bits > servkey.bytes * 8) {
2477 bombout(("SSH1 public keys were badly formatted"));
2478 crStop(0);
2479 }
2480
2481 s->len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes);
2482
2483 s->rsabuf = snewn(s->len, unsigned char);
2484 if (!s->rsabuf)
2485 fatalbox("Out of memory");
2486
2487 /*
2488 * Verify the host key.
2489 */
2490 {
2491 /*
2492 * First format the key into a string.
2493 */
2494 int len = rsastr_len(&hostkey);
2495 char fingerprint[100];
2496 char *keystr = snewn(len, char);
2497 if (!keystr)
2498 fatalbox("Out of memory");
2499 rsastr_fmt(keystr, &hostkey);
2500 rsa_fingerprint(fingerprint, sizeof(fingerprint), &hostkey);
2501 verify_ssh_host_key(ssh->frontend,
2502 ssh->savedhost, ssh->savedport, "rsa", keystr,
2503 fingerprint);
2504 sfree(keystr);
2505 }
2506
2507 for (i = 0; i < 32; i++) {
2508 s->rsabuf[i] = ssh->session_key[i];
2509 if (i < 16)
2510 s->rsabuf[i] ^= s->session_id[i];
2511 }
2512
2513 if (hostkey.bytes > servkey.bytes) {
2514 ret = rsaencrypt(s->rsabuf, 32, &servkey);
2515 if (ret)
2516 ret = rsaencrypt(s->rsabuf, servkey.bytes, &hostkey);
2517 } else {
2518 ret = rsaencrypt(s->rsabuf, 32, &hostkey);
2519 if (ret)
2520 ret = rsaencrypt(s->rsabuf, hostkey.bytes, &servkey);
2521 }
2522 if (!ret) {
2523 bombout(("SSH1 public key encryptions failed due to bad formatting"));
2524 crStop(0);
2525 }
2526
2527 logevent("Encrypted session key");
2528
2529 {
2530 int cipher_chosen = 0, warn = 0;
2531 char *cipher_string = NULL;
2532 int i;
2533 for (i = 0; !cipher_chosen && i < CIPHER_MAX; i++) {
2534 int next_cipher = ssh->cfg.ssh_cipherlist[i];
2535 if (next_cipher == CIPHER_WARN) {
2536 /* If/when we choose a cipher, warn about it */
2537 warn = 1;
2538 } else if (next_cipher == CIPHER_AES) {
2539 /* XXX Probably don't need to mention this. */
2540 logevent("AES not supported in SSH1, skipping");
2541 } else {
2542 switch (next_cipher) {
2543 case CIPHER_3DES: s->cipher_type = SSH_CIPHER_3DES;
2544 cipher_string = "3DES"; break;
2545 case CIPHER_BLOWFISH: s->cipher_type = SSH_CIPHER_BLOWFISH;
2546 cipher_string = "Blowfish"; break;
2547 case CIPHER_DES: s->cipher_type = SSH_CIPHER_DES;
2548 cipher_string = "single-DES"; break;
2549 }
2550 if (s->supported_ciphers_mask & (1 << s->cipher_type))
2551 cipher_chosen = 1;
2552 }
2553 }
2554 if (!cipher_chosen) {
2555 if ((s->supported_ciphers_mask & (1 << SSH_CIPHER_3DES)) == 0)
2556 bombout(("Server violates SSH 1 protocol by not "
2557 "supporting 3DES encryption"));
2558 else
2559 /* shouldn't happen */
2560 bombout(("No supported ciphers found"));
2561 crStop(0);
2562 }
2563
2564 /* Warn about chosen cipher if necessary. */
2565 if (warn)
2566 askcipher(ssh->frontend, cipher_string, 0);
2567 }
2568
2569 switch (s->cipher_type) {
2570 case SSH_CIPHER_3DES:
2571 logevent("Using 3DES encryption");
2572 break;
2573 case SSH_CIPHER_DES:
2574 logevent("Using single-DES encryption");
2575 break;
2576 case SSH_CIPHER_BLOWFISH:
2577 logevent("Using Blowfish encryption");
2578 break;
2579 }
2580
2581 send_packet(ssh, SSH1_CMSG_SESSION_KEY,
2582 PKT_CHAR, s->cipher_type,
2583 PKT_DATA, cookie, 8,
2584 PKT_CHAR, (s->len * 8) >> 8, PKT_CHAR, (s->len * 8) & 0xFF,
2585 PKT_DATA, s->rsabuf, s->len,
2586 PKT_INT, ssh->v1_local_protoflags, PKT_END);
2587
2588 logevent("Trying to enable encryption...");
2589
2590 sfree(s->rsabuf);
2591
2592 ssh->cipher = (s->cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 :
2593 s->cipher_type == SSH_CIPHER_DES ? &ssh_des :
2594 &ssh_3des);
2595 ssh->v1_cipher_ctx = ssh->cipher->make_context();
2596 ssh->cipher->sesskey(ssh->v1_cipher_ctx, ssh->session_key);
2597 logeventf(ssh, "Initialised %s encryption", ssh->cipher->text_name);
2598
2599 ssh->crcda_ctx = crcda_make_context();
2600 logevent("Installing CRC compensation attack detector");
2601
2602 if (servkey.modulus) {
2603 sfree(servkey.modulus);
2604 servkey.modulus = NULL;
2605 }
2606 if (servkey.exponent) {
2607 sfree(servkey.exponent);
2608 servkey.exponent = NULL;
2609 }
2610 if (hostkey.modulus) {
2611 sfree(hostkey.modulus);
2612 hostkey.modulus = NULL;
2613 }
2614 if (hostkey.exponent) {
2615 sfree(hostkey.exponent);
2616 hostkey.exponent = NULL;
2617 }
2618 crWaitUntil(ispkt);
2619
2620 if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
2621 bombout(("Encryption not successfully enabled"));
2622 crStop(0);
2623 }
2624
2625 logevent("Successfully started encryption");
2626
2627 fflush(stdout);
2628 {
2629 if ((flags & FLAG_INTERACTIVE) && !*ssh->cfg.username) {
2630 if (ssh_get_line && !ssh_getline_pw_only) {
2631 if (!ssh_get_line("login as: ",
2632 s->username, sizeof(s->username), FALSE)) {
2633 /*
2634 * get_line failed to get a username.
2635 * Terminate.
2636 */
2637 logevent("No username provided. Abandoning session.");
2638 ssh_closing((Plug)ssh, NULL, 0, 0);
2639 crStop(1);
2640 }
2641 } else {
2642 int ret; /* need not be kept over crReturn */
2643 c_write_str(ssh, "login as: ");
2644 ssh->send_ok = 1;
2645
2646 setup_userpass_input(ssh, s->username, sizeof(s->username), 1);
2647 do {
2648 crWaitUntil(!ispkt);
2649 ret = process_userpass_input(ssh, in, inlen);
2650 } while (ret == 0);
2651 if (ret < 0)
2652 cleanup_exit(0);
2653 c_write_str(ssh, "\r\n");
2654 }
2655 } else {
2656 strncpy(s->username, ssh->cfg.username, sizeof(s->username));
2657 s->username[sizeof(s->username)-1] = '\0';
2658 }
2659
2660 send_packet(ssh, SSH1_CMSG_USER, PKT_STR, s->username, PKT_END);
2661 {
2662 char userlog[22 + sizeof(s->username)];
2663 sprintf(userlog, "Sent username \"%s\"", s->username);
2664 logevent(userlog);
2665 if (flags & FLAG_INTERACTIVE &&
2666 (!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) {
2667 strcat(userlog, "\r\n");
2668 c_write_str(ssh, userlog);
2669 }
2670 }
2671 }
2672
2673 crWaitUntil(ispkt);
2674
2675 if ((ssh->remote_bugs & BUG_CHOKES_ON_RSA)) {
2676 /* We must not attempt PK auth. Pretend we've already tried it. */
2677 s->tried_publickey = s->tried_agent = 1;
2678 } else {
2679 s->tried_publickey = s->tried_agent = 0;
2680 }
2681 s->tis_auth_refused = s->ccard_auth_refused = 0;
2682 /* Load the public half of ssh->cfg.keyfile so we notice if it's in Pageant */
2683 if (!filename_is_null(ssh->cfg.keyfile)) {
2684 if (!rsakey_pubblob(&ssh->cfg.keyfile,
2685 &s->publickey_blob, &s->publickey_bloblen, NULL))
2686 s->publickey_blob = NULL;
2687 } else
2688 s->publickey_blob = NULL;
2689
2690 while (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2691 s->pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
2692
2693 if (agent_exists() && !s->tried_agent) {
2694 /*
2695 * Attempt RSA authentication using Pageant.
2696 */
2697 void *r;
2698
2699 s->authed = FALSE;
2700 s->tried_agent = 1;
2701 logevent("Pageant is running. Requesting keys.");
2702
2703 /* Request the keys held by the agent. */
2704 PUT_32BIT(s->request, 1);
2705 s->request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES;
2706 if (!agent_query(s->request, 5, &r, &s->responselen,
2707 ssh_agent_callback, ssh)) {
2708 do {
2709 crReturn(0);
2710 if (ispkt) {
2711 bombout(("Unexpected data from server while waiting"
2712 " for agent response"));
2713 crStop(0);
2714 }
2715 } while (ispkt || inlen > 0);
2716 r = ssh->agent_response;
2717 s->responselen = ssh->agent_response_len;
2718 }
2719 s->response = (unsigned char *) r;
2720 if (s->response && s->responselen >= 5 &&
2721 s->response[4] == SSH1_AGENT_RSA_IDENTITIES_ANSWER) {
2722 s->p = s->response + 5;
2723 s->nkeys = GET_32BIT(s->p);
2724 s->p += 4;
2725 {
2726 char buf[64];
2727 sprintf(buf, "Pageant has %d SSH1 keys", s->nkeys);
2728 logevent(buf);
2729 }
2730 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
2731 {
2732 char buf[64];
2733 sprintf(buf, "Trying Pageant key #%d", s->keyi);
2734 logevent(buf);
2735 }
2736 if (s->publickey_blob &&
2737 !memcmp(s->p, s->publickey_blob,
2738 s->publickey_bloblen)) {
2739 logevent("This key matches configured key file");
2740 s->tried_publickey = 1;
2741 }
2742 s->p += 4;
2743 {
2744 int n, ok = FALSE;
2745 do { /* do while (0) to make breaking easy */
2746 n = ssh1_read_bignum
2747 (s->p, s->responselen-(s->p-s->response),
2748 &s->key.exponent);
2749 if (n < 0)
2750 break;
2751 s->p += n;
2752 n = ssh1_read_bignum
2753 (s->p, s->responselen-(s->p-s->response),
2754 &s->key.modulus);
2755 if (n < 0)
2756 break;
2757 s->p += n;
2758 if (s->responselen - (s->p-s->response) < 4)
2759 break;
2760 s->commentlen = GET_32BIT(s->p);
2761 s->p += 4;
2762 if (s->responselen - (s->p-s->response) <
2763 s->commentlen)
2764 break;
2765 s->commentp = (char *)s->p;
2766 s->p += s->commentlen;
2767 ok = TRUE;
2768 } while (0);
2769 if (!ok) {
2770 logevent("Pageant key list packet was truncated");
2771 break;
2772 }
2773 }
2774 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
2775 PKT_BIGNUM, s->key.modulus, PKT_END);
2776 crWaitUntil(ispkt);
2777 if (ssh->pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
2778 logevent("Key refused");
2779 continue;
2780 }
2781 logevent("Received RSA challenge");
2782 if ((s->challenge = ssh1_pkt_getmp(ssh)) == NULL) {
2783 bombout(("Server's RSA challenge was badly formatted"));
2784 crStop(0);
2785 }
2786
2787 {
2788 char *agentreq, *q, *ret;
2789 void *vret;
2790 int len, retlen;
2791 len = 1 + 4; /* message type, bit count */
2792 len += ssh1_bignum_length(s->key.exponent);
2793 len += ssh1_bignum_length(s->key.modulus);
2794 len += ssh1_bignum_length(s->challenge);
2795 len += 16; /* session id */
2796 len += 4; /* response format */
2797 agentreq = snewn(4 + len, char);
2798 PUT_32BIT(agentreq, len);
2799 q = agentreq + 4;
2800 *q++ = SSH1_AGENTC_RSA_CHALLENGE;
2801 PUT_32BIT(q, bignum_bitcount(s->key.modulus));
2802 q += 4;
2803 q += ssh1_write_bignum(q, s->key.exponent);
2804 q += ssh1_write_bignum(q, s->key.modulus);
2805 q += ssh1_write_bignum(q, s->challenge);
2806 memcpy(q, s->session_id, 16);
2807 q += 16;
2808 PUT_32BIT(q, 1); /* response format */
2809 if (!agent_query(agentreq, len + 4, &vret, &retlen,
2810 ssh_agent_callback, ssh)) {
2811 sfree(agentreq);
2812 do {
2813 crReturn(0);
2814 if (ispkt) {
2815 bombout(("Unexpected data from server"
2816 " while waiting for agent"
2817 " response"));
2818 crStop(0);
2819 }
2820 } while (ispkt || inlen > 0);
2821 vret = ssh->agent_response;
2822 retlen = ssh->agent_response_len;
2823 } else
2824 sfree(agentreq);
2825 ret = vret;
2826 if (ret) {
2827 if (ret[4] == SSH1_AGENT_RSA_RESPONSE) {
2828 logevent("Sending Pageant's response");
2829 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
2830 PKT_DATA, ret + 5, 16,
2831 PKT_END);
2832 sfree(ret);
2833 crWaitUntil(ispkt);
2834 if (ssh->pktin.type == SSH1_SMSG_SUCCESS) {
2835 logevent
2836 ("Pageant's response accepted");
2837 if (flags & FLAG_VERBOSE) {
2838 c_write_str(ssh, "Authenticated using"
2839 " RSA key \"");
2840 c_write(ssh, s->commentp,
2841 s->commentlen);
2842 c_write_str(ssh, "\" from agent\r\n");
2843 }
2844 s->authed = TRUE;
2845 } else
2846 logevent
2847 ("Pageant's response not accepted");
2848 } else {
2849 logevent
2850 ("Pageant failed to answer challenge");
2851 sfree(ret);
2852 }
2853 } else {
2854 logevent("No reply received from Pageant");
2855 }
2856 }
2857 freebn(s->key.exponent);
2858 freebn(s->key.modulus);
2859 freebn(s->challenge);
2860 if (s->authed)
2861 break;
2862 }
2863 sfree(s->response);
2864 }
2865 if (s->authed)
2866 break;
2867 }
2868 if (!filename_is_null(ssh->cfg.keyfile) && !s->tried_publickey)
2869 s->pwpkt_type = SSH1_CMSG_AUTH_RSA;
2870
2871 if (ssh->cfg.try_tis_auth &&
2872 (s->supported_auths_mask & (1 << SSH1_AUTH_TIS)) &&
2873 !s->tis_auth_refused) {
2874 s->pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
2875 logevent("Requested TIS authentication");
2876 send_packet(ssh, SSH1_CMSG_AUTH_TIS, PKT_END);
2877 crWaitUntil(ispkt);
2878 if (ssh->pktin.type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
2879 logevent("TIS authentication declined");
2880 if (flags & FLAG_INTERACTIVE)
2881 c_write_str(ssh, "TIS authentication refused.\r\n");
2882 s->tis_auth_refused = 1;
2883 continue;
2884 } else {
2885 char *challenge;
2886 int challengelen;
2887
2888 ssh_pkt_getstring(ssh, &challenge, &challengelen);
2889 if (!challenge) {
2890 bombout(("TIS challenge packet was badly formed"));
2891 crStop(0);
2892 }
2893 logevent("Received TIS challenge");
2894 if (challengelen > sizeof(s->prompt) - 1)
2895 challengelen = sizeof(s->prompt) - 1;/* prevent overrun */
2896 memcpy(s->prompt, challenge, challengelen);
2897 /* Prompt heuristic comes from OpenSSH */
2898 strncpy(s->prompt + challengelen,
2899 memchr(s->prompt, '\n', challengelen) ?
2900 "": "\r\nResponse: ",
2901 (sizeof s->prompt) - challengelen);
2902 s->prompt[(sizeof s->prompt) - 1] = '\0';
2903 }
2904 }
2905 if (ssh->cfg.try_tis_auth &&
2906 (s->supported_auths_mask & (1 << SSH1_AUTH_CCARD)) &&
2907 !s->ccard_auth_refused) {
2908 s->pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE;
2909 logevent("Requested CryptoCard authentication");
2910 send_packet(ssh, SSH1_CMSG_AUTH_CCARD, PKT_END);
2911 crWaitUntil(ispkt);
2912 if (ssh->pktin.type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
2913 logevent("CryptoCard authentication declined");
2914 c_write_str(ssh, "CryptoCard authentication refused.\r\n");
2915 s->ccard_auth_refused = 1;
2916 continue;
2917 } else {
2918 char *challenge;
2919 int challengelen;
2920
2921 ssh_pkt_getstring(ssh, &challenge, &challengelen);
2922 if (!challenge) {
2923 bombout(("CryptoCard challenge packet was badly formed"));
2924 crStop(0);
2925 }
2926 logevent("Received CryptoCard challenge");
2927 if (challengelen > sizeof(s->prompt) - 1)
2928 challengelen = sizeof(s->prompt) - 1;/* prevent overrun */
2929 memcpy(s->prompt, challenge, challengelen);
2930 strncpy(s->prompt + challengelen,
2931 memchr(s->prompt, '\n', challengelen) ?
2932 "" : "\r\nResponse: ",
2933 sizeof(s->prompt) - challengelen);
2934 s->prompt[sizeof(s->prompt) - 1] = '\0';
2935 }
2936 }
2937 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
2938 sprintf(s->prompt, "%.90s@%.90s's password: ",
2939 s->username, ssh->savedhost);
2940 }
2941 if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) {
2942 char *comment = NULL;
2943 int type;
2944 char msgbuf[256];
2945 if (flags & FLAG_VERBOSE)
2946 c_write_str(ssh, "Trying public key authentication.\r\n");
2947 logeventf(ssh, "Trying public key \"%s\"",
2948 filename_to_str(&ssh->cfg.keyfile));
2949 type = key_type(&ssh->cfg.keyfile);
2950 if (type != SSH_KEYTYPE_SSH1) {
2951 sprintf(msgbuf, "Key is of wrong type (%s)",
2952 key_type_to_str(type));
2953 logevent(msgbuf);
2954 c_write_str(ssh, msgbuf);
2955 c_write_str(ssh, "\r\n");
2956 s->tried_publickey = 1;
2957 continue;
2958 }
2959 if (!rsakey_encrypted(&ssh->cfg.keyfile, &comment)) {
2960 if (flags & FLAG_VERBOSE)
2961 c_write_str(ssh, "No passphrase required.\r\n");
2962 goto tryauth;
2963 }
2964 sprintf(s->prompt, "Passphrase for key \"%.100s\": ", comment);
2965 sfree(comment);
2966 }
2967
2968 /*
2969 * Show password prompt, having first obtained it via a TIS
2970 * or CryptoCard exchange if we're doing TIS or CryptoCard
2971 * authentication.
2972 */
2973 if (ssh_get_line) {
2974 if (!ssh_get_line(s->prompt, s->password,
2975 sizeof(s->password), TRUE)) {
2976 /*
2977 * get_line failed to get a password (for example
2978 * because one was supplied on the command line
2979 * which has already failed to work). Terminate.
2980 */
2981 send_packet(ssh, SSH1_MSG_DISCONNECT,
2982 PKT_STR, "No more passwords available to try",
2983 PKT_END);
2984 logevent("Unable to authenticate");
2985 connection_fatal(ssh->frontend, "Unable to authenticate");
2986 ssh_closing((Plug)ssh, NULL, 0, 0);
2987 crStop(1);
2988 }
2989 } else {
2990 /* Prompt may have come from server. We've munged it a bit, so
2991 * we know it to be zero-terminated at least once. */
2992 int ret; /* need not be saved over crReturn */
2993 c_write_untrusted(ssh, s->prompt, strlen(s->prompt));
2994 s->pos = 0;
2995
2996 setup_userpass_input(ssh, s->password, sizeof(s->password), 0);
2997 do {
2998 crWaitUntil(!ispkt);
2999 ret = process_userpass_input(ssh, in, inlen);
3000 } while (ret == 0);
3001 if (ret < 0)
3002 cleanup_exit(0);
3003 c_write_str(ssh, "\r\n");
3004 }
3005
3006 tryauth:
3007 if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) {
3008 /*
3009 * Try public key authentication with the specified
3010 * key file.
3011 */
3012 s->tried_publickey = 1;
3013
3014 {
3015 const char *error = NULL;
3016 int ret = loadrsakey(&ssh->cfg.keyfile, &s->key, s->password,
3017 &error);
3018 if (ret == 0) {
3019 c_write_str(ssh, "Couldn't load private key from ");
3020 c_write_str(ssh, filename_to_str(&ssh->cfg.keyfile));
3021 c_write_str(ssh, " (");
3022 c_write_str(ssh, error);
3023 c_write_str(ssh, ").\r\n");
3024 continue; /* go and try password */
3025 }
3026 if (ret == -1) {
3027 c_write_str(ssh, "Wrong passphrase.\r\n");
3028 s->tried_publickey = 0;
3029 continue; /* try again */
3030 }
3031 }
3032
3033 /*
3034 * Send a public key attempt.
3035 */
3036 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
3037 PKT_BIGNUM, s->key.modulus, PKT_END);
3038
3039 crWaitUntil(ispkt);
3040 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3041 c_write_str(ssh, "Server refused our public key.\r\n");
3042 continue; /* go and try password */
3043 }
3044 if (ssh->pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
3045 bombout(("Bizarre response to offer of public key"));
3046 crStop(0);
3047 }
3048
3049 {
3050 int i;
3051 unsigned char buffer[32];
3052 Bignum challenge, response;
3053
3054 if ((challenge = ssh1_pkt_getmp(ssh)) == NULL) {
3055 bombout(("Server's RSA challenge was badly formatted"));
3056 crStop(0);
3057 }
3058 response = rsadecrypt(challenge, &s->key);
3059 freebn(s->key.private_exponent);/* burn the evidence */
3060
3061 for (i = 0; i < 32; i++) {
3062 buffer[i] = bignum_byte(response, 31 - i);
3063 }
3064
3065 MD5Init(&md5c);
3066 MD5Update(&md5c, buffer, 32);
3067 MD5Update(&md5c, s->session_id, 16);
3068 MD5Final(buffer, &md5c);
3069
3070 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
3071 PKT_DATA, buffer, 16, PKT_END);
3072
3073 freebn(challenge);
3074 freebn(response);
3075 }
3076
3077 crWaitUntil(ispkt);
3078 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3079 if (flags & FLAG_VERBOSE)
3080 c_write_str(ssh, "Failed to authenticate with"
3081 " our public key.\r\n");
3082 continue; /* go and try password */
3083 } else if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
3084 bombout(("Bizarre response to RSA authentication response"));
3085 crStop(0);
3086 }
3087
3088 break; /* we're through! */
3089 } else {
3090 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
3091 /*
3092 * Defence against traffic analysis: we send a
3093 * whole bunch of packets containing strings of
3094 * different lengths. One of these strings is the
3095 * password, in a SSH1_CMSG_AUTH_PASSWORD packet.
3096 * The others are all random data in
3097 * SSH1_MSG_IGNORE packets. This way a passive
3098 * listener can't tell which is the password, and
3099 * hence can't deduce the password length.
3100 *
3101 * Anybody with a password length greater than 16
3102 * bytes is going to have enough entropy in their
3103 * password that a listener won't find it _that_
3104 * much help to know how long it is. So what we'll
3105 * do is:
3106 *
3107 * - if password length < 16, we send 15 packets
3108 * containing string lengths 1 through 15
3109 *
3110 * - otherwise, we let N be the nearest multiple
3111 * of 8 below the password length, and send 8
3112 * packets containing string lengths N through
3113 * N+7. This won't obscure the order of
3114 * magnitude of the password length, but it will
3115 * introduce a bit of extra uncertainty.
3116 *
3117 * A few servers (the old 1.2.18 through 1.2.22)
3118 * can't deal with SSH1_MSG_IGNORE. For these
3119 * servers, we need an alternative defence. We make
3120 * use of the fact that the password is interpreted
3121 * as a C string: so we can append a NUL, then some
3122 * random data.
3123 *
3124 * One server (a Cisco one) can deal with neither
3125 * SSH1_MSG_IGNORE _nor_ a padded password string.
3126 * For this server we are left with no defences
3127 * against password length sniffing.
3128 */
3129 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE)) {
3130 /*
3131 * The server can deal with SSH1_MSG_IGNORE, so
3132 * we can use the primary defence.
3133 */
3134 int bottom, top, pwlen, i;
3135 char *randomstr;
3136
3137 pwlen = strlen(s->password);
3138 if (pwlen < 16) {
3139 bottom = 0; /* zero length passwords are OK! :-) */
3140 top = 15;
3141 } else {
3142 bottom = pwlen & ~7;
3143 top = bottom + 7;
3144 }
3145
3146 assert(pwlen >= bottom && pwlen <= top);
3147
3148 randomstr = snewn(top + 1, char);
3149
3150 for (i = bottom; i <= top; i++) {
3151 if (i == pwlen)
3152 defer_packet(ssh, s->pwpkt_type,
3153 PKT_STR, s->password, PKT_END);
3154 else {
3155 for (j = 0; j < i; j++) {
3156 do {
3157 randomstr[j] = random_byte();
3158 } while (randomstr[j] == '\0');
3159 }
3160 randomstr[i] = '\0';
3161 defer_packet(ssh, SSH1_MSG_IGNORE,
3162 PKT_STR, randomstr, PKT_END);
3163 }
3164 }
3165 logevent("Sending password with camouflage packets");
3166 ssh_pkt_defersend(ssh);
3167 sfree(randomstr);
3168 }
3169 else if (!(ssh->remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) {
3170 /*
3171 * The server can't deal with SSH1_MSG_IGNORE
3172 * but can deal with padded passwords, so we
3173 * can use the secondary defence.
3174 */
3175 char string[64];
3176 char *ss;
3177 int len;
3178
3179 len = strlen(s->password);
3180 if (len < sizeof(string)) {
3181 ss = string;
3182 strcpy(string, s->password);
3183 len++; /* cover the zero byte */
3184 while (len < sizeof(string)) {
3185 string[len++] = (char) random_byte();
3186 }
3187 } else {
3188 ss = s->password;
3189 }
3190 logevent("Sending length-padded password");
3191 send_packet(ssh, s->pwpkt_type, PKT_INT, len,
3192 PKT_DATA, ss, len, PKT_END);
3193 } else {
3194 /*
3195 * The server has _both_
3196 * BUG_CHOKES_ON_SSH1_IGNORE and
3197 * BUG_NEEDS_SSH1_PLAIN_PASSWORD. There is
3198 * therefore nothing we can do.
3199 */
3200 int len;
3201 len = strlen(s->password);
3202 logevent("Sending unpadded password");
3203 send_packet(ssh, s->pwpkt_type, PKT_INT, len,
3204 PKT_DATA, s->password, len, PKT_END);
3205 }
3206 } else {
3207 send_packet(ssh, s->pwpkt_type, PKT_STR, s->password, PKT_END);
3208 }
3209 }
3210 logevent("Sent password");
3211 memset(s->password, 0, strlen(s->password));
3212 crWaitUntil(ispkt);
3213 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3214 if (flags & FLAG_VERBOSE)
3215 c_write_str(ssh, "Access denied\r\n");
3216 logevent("Authentication refused");
3217 } else if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
3218 bombout(("Strange packet received, type %d", ssh->pktin.type));
3219 crStop(0);
3220 }
3221 }
3222
3223 logevent("Authentication successful");
3224
3225 crFinish(1);
3226 }
3227
3228 void sshfwd_close(struct ssh_channel *c)
3229 {
3230 Ssh ssh = c->ssh;
3231
3232 if (ssh->state != SSH_STATE_SESSION) {
3233 assert(ssh->state == SSH_STATE_CLOSED);
3234 return;
3235 }
3236
3237 if (c && !c->closes) {
3238 /*
3239 * If the channel's remoteid is -1, we have sent
3240 * CHANNEL_OPEN for this channel, but it hasn't even been
3241 * acknowledged by the server. So we must set a close flag
3242 * on it now, and then when the server acks the channel
3243 * open, we can close it then.
3244 */
3245 if (((int)c->remoteid) != -1) {
3246 if (ssh->version == 1) {
3247 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid,
3248 PKT_END);
3249 } else {
3250 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
3251 ssh2_pkt_adduint32(ssh, c->remoteid);
3252 ssh2_pkt_send(ssh);
3253 }
3254 }
3255 c->closes = 1; /* sent MSG_CLOSE */
3256 if (c->type == CHAN_X11) {
3257 c->u.x11.s = NULL;
3258 logevent("Forwarded X11 connection terminated");
3259 } else if (c->type == CHAN_SOCKDATA ||
3260 c->type == CHAN_SOCKDATA_DORMANT) {
3261 c->u.pfd.s = NULL;
3262 logevent("Forwarded port closed");
3263 }
3264 }
3265 }
3266
3267 int sshfwd_write(struct ssh_channel *c, char *buf, int len)
3268 {
3269 Ssh ssh = c->ssh;
3270
3271 if (ssh->state != SSH_STATE_SESSION) {
3272 assert(ssh->state == SSH_STATE_CLOSED);
3273 return 0;
3274 }
3275
3276 if (ssh->version == 1) {
3277 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
3278 PKT_INT, c->remoteid,
3279 PKT_INT, len, PKT_DATA, buf, len, PKT_END);
3280 /*
3281 * In SSH1 we can return 0 here - implying that forwarded
3282 * connections are never individually throttled - because
3283 * the only circumstance that can cause throttling will be
3284 * the whole SSH connection backing up, in which case
3285 * _everything_ will be throttled as a whole.
3286 */
3287 return 0;
3288 } else {
3289 ssh2_add_channel_data(c, buf, len);
3290 return ssh2_try_send(c);
3291 }
3292 }
3293
3294 void sshfwd_unthrottle(struct ssh_channel *c, int bufsize)
3295 {
3296 Ssh ssh = c->ssh;
3297
3298 if (ssh->state != SSH_STATE_SESSION) {
3299 assert(ssh->state == SSH_STATE_CLOSED);
3300 return;
3301 }
3302
3303 if (ssh->version == 1) {
3304 if (c->v.v1.throttling && bufsize < SSH1_BUFFER_LIMIT) {
3305 c->v.v1.throttling = 0;
3306 ssh1_throttle(ssh, -1);
3307 }
3308 } else {
3309 ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
3310 }
3311 }
3312
3313 static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
3314 {
3315 crBegin(ssh->ssh1_protocol_crstate);
3316
3317 random_init();
3318
3319 while (!do_ssh1_login(ssh, in, inlen, ispkt)) {
3320 crReturnV;
3321 }
3322 if (ssh->state == SSH_STATE_CLOSED)
3323 crReturnV;
3324
3325 if (ssh->cfg.agentfwd && agent_exists()) {
3326 logevent("Requesting agent forwarding");
3327 send_packet(ssh, SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END);
3328 do {
3329 crReturnV;
3330 } while (!ispkt);
3331 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3332 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3333 bombout(("Protocol confusion"));
3334 crStopV;
3335 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3336 logevent("Agent forwarding refused");
3337 } else {
3338 logevent("Agent forwarding enabled");
3339 ssh->agentfwd_enabled = TRUE;
3340 }
3341 }
3342
3343 if (ssh->cfg.x11_forward) {
3344 char proto[20], data[64];
3345 logevent("Requesting X11 forwarding");
3346 ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
3347 data, sizeof(data), ssh->cfg.x11_auth);
3348 x11_get_real_auth(ssh->x11auth, ssh->cfg.x11_display);
3349 if (ssh->v1_local_protoflags & SSH1_PROTOFLAG_SCREEN_NUMBER) {
3350 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
3351 PKT_STR, proto, PKT_STR, data,
3352 PKT_INT, x11_get_screen_number(ssh->cfg.x11_display),
3353 PKT_END);
3354 } else {
3355 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
3356 PKT_STR, proto, PKT_STR, data, PKT_END);
3357 }
3358 do {
3359 crReturnV;
3360 } while (!ispkt);
3361 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3362 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3363 bombout(("Protocol confusion"));
3364 crStopV;
3365 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3366 logevent("X11 forwarding refused");
3367 } else {
3368 logevent("X11 forwarding enabled");
3369 ssh->X11_fwd_enabled = TRUE;
3370 }
3371 }
3372
3373 {
3374 char type;
3375 int n;
3376 int sport,dport,sserv,dserv;
3377 char sports[256], dports[256], saddr[256], host[256];
3378
3379 ssh->rportfwds = newtree234(ssh_rportcmp_ssh1);
3380 /* Add port forwardings. */
3381 ssh->portfwd_strptr = ssh->cfg.portfwd;
3382 while (*ssh->portfwd_strptr) {
3383 type = *ssh->portfwd_strptr++;
3384 saddr[0] = '\0';
3385 n = 0;
3386 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != '\t') {
3387 if (*ssh->portfwd_strptr == ':') {
3388 /*
3389 * We've seen a colon in the middle of the
3390 * source port number. This means that
3391 * everything we've seen until now is the
3392 * source _address_, so we'll move it into
3393 * saddr and start sports from the beginning
3394 * again.
3395 */
3396 ssh->portfwd_strptr++;
3397 sports[n] = '\0';
3398 strcpy(saddr, sports);
3399 n = 0;
3400 }
3401 if (n < 255) sports[n++] = *ssh->portfwd_strptr++;
3402 }
3403 sports[n] = 0;
3404 if (type != 'D') {
3405 if (*ssh->portfwd_strptr == '\t')
3406 ssh->portfwd_strptr++;
3407 n = 0;
3408 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':') {
3409 if (n < 255) host[n++] = *ssh->portfwd_strptr++;
3410 }
3411 host[n] = 0;
3412 if (*ssh->portfwd_strptr == ':')
3413 ssh->portfwd_strptr++;
3414 n = 0;
3415 while (*ssh->portfwd_strptr) {
3416 if (n < 255) dports[n++] = *ssh->portfwd_strptr++;
3417 }
3418 dports[n] = 0;
3419 ssh->portfwd_strptr++;
3420 dport = atoi(dports);
3421 dserv = 0;
3422 if (dport == 0) {
3423 dserv = 1;
3424 dport = net_service_lookup(dports);
3425 if (!dport) {
3426 logeventf(ssh, "Service lookup failed for"
3427 " destination port \"%s\"", dports);
3428 }
3429 }
3430 } else {
3431 while (*ssh->portfwd_strptr) ssh->portfwd_strptr++;
3432 dport = dserv = -1;
3433 ssh->portfwd_strptr++; /* eat the NUL and move to next one */
3434 }
3435 sport = atoi(sports);
3436 sserv = 0;
3437 if (sport == 0) {
3438 sserv = 1;
3439 sport = net_service_lookup(sports);
3440 if (!sport) {
3441 logeventf(ssh, "Service lookup failed for source"
3442 " port \"%s\"", sports);
3443 }
3444 }
3445 if (sport && dport) {
3446 if (type == 'L') {
3447 pfd_addforward(host, dport, *saddr ? saddr : NULL,
3448 sport, ssh, &ssh->cfg);
3449 logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
3450 " forwarding to %s:%.*s%.*s%d%.*s",
3451 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
3452 (int)(*saddr?1:0), ":",
3453 (int)(sserv ? strlen(sports) : 0), sports,
3454 sserv, "(", sport, sserv, ")",
3455 host,
3456 (int)(dserv ? strlen(dports) : 0), dports,
3457 dserv, "(", dport, dserv, ")");
3458 } else if (type == 'D') {
3459 pfd_addforward(NULL, -1, *saddr ? saddr : NULL,
3460 sport, ssh, &ssh->cfg);
3461 logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
3462 " doing SOCKS dynamic forwarding",
3463 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
3464 (int)(*saddr?1:0), ":",
3465 (int)(sserv ? strlen(sports) : 0), sports,
3466 sserv, "(", sport, sserv, ")");
3467 } else {
3468 struct ssh_rportfwd *pf;
3469 pf = snew(struct ssh_rportfwd);
3470 strcpy(pf->dhost, host);
3471 pf->dport = dport;
3472 if (saddr) {
3473 logeventf(ssh,
3474 "SSH1 cannot handle source address spec \"%s:%d\"; ignoring",
3475 saddr, sport);
3476 }
3477 if (add234(ssh->rportfwds, pf) != pf) {
3478 logeventf(ssh,
3479 "Duplicate remote port forwarding to %s:%d",
3480 host, dport);
3481 sfree(pf);
3482 } else {
3483 logeventf(ssh, "Requesting remote port %.*s%.*s%d%.*s"
3484 " forward to %s:%.*s%.*s%d%.*s",
3485 (int)(sserv ? strlen(sports) : 0), sports,
3486 sserv, "(", sport, sserv, ")",
3487 host,
3488 (int)(dserv ? strlen(dports) : 0), dports,
3489 dserv, "(", dport, dserv, ")");
3490 send_packet(ssh, SSH1_CMSG_PORT_FORWARD_REQUEST,
3491 PKT_INT, sport,
3492 PKT_STR, host,
3493 PKT_INT, dport,
3494 PKT_END);
3495 do {
3496 crReturnV;
3497 } while (!ispkt);
3498 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3499 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3500 bombout(("Protocol confusion"));
3501 crStopV;
3502 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3503 c_write_str(ssh, "Server refused port"
3504 " forwarding\r\n");
3505 }
3506 logevent("Remote port forwarding enabled");
3507 }
3508 }
3509 }
3510 }
3511 }
3512
3513 if (!ssh->cfg.nopty) {
3514 /* Unpick the terminal-speed string. */
3515 /* XXX perhaps we should allow no speeds to be sent. */
3516 ssh->ospeed = 38400; ssh->ispeed = 38400; /* last-resort defaults */
3517 sscanf(ssh->cfg.termspeed, "%d,%d", &ssh->ospeed, &ssh->ispeed);
3518 /* Send the pty request. */
3519 send_packet(ssh, SSH1_CMSG_REQUEST_PTY,
3520 PKT_STR, ssh->cfg.termtype,
3521 PKT_INT, ssh->term_height,
3522 PKT_INT, ssh->term_width,
3523 PKT_INT, 0, PKT_INT, 0, /* width,height in pixels */
3524 PKT_CHAR, 192, PKT_INT, ssh->ispeed, /* TTY_OP_ISPEED */
3525 PKT_CHAR, 193, PKT_INT, ssh->ospeed, /* TTY_OP_OSPEED */
3526 PKT_CHAR, 0, PKT_END);
3527 ssh->state = SSH_STATE_INTERMED;
3528 do {
3529 crReturnV;
3530 } while (!ispkt);
3531 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3532 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3533 bombout(("Protocol confusion"));
3534 crStopV;
3535 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3536 c_write_str(ssh, "Server refused to allocate pty\r\n");
3537 ssh->editing = ssh->echoing = 1;
3538 }
3539 logeventf(ssh, "Allocated pty (ospeed %dbps, ispeed %dbps)",
3540 ssh->ospeed, ssh->ispeed);
3541 } else {
3542 ssh->editing = ssh->echoing = 1;
3543 }
3544
3545 if (ssh->cfg.compression) {
3546 send_packet(ssh, SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END);
3547 do {
3548 crReturnV;
3549 } while (!ispkt);
3550 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3551 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3552 bombout(("Protocol confusion"));
3553 crStopV;
3554 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3555 c_write_str(ssh, "Server refused to compress\r\n");
3556 }
3557 logevent("Started compression");
3558 ssh->v1_compressing = TRUE;
3559 ssh->cs_comp_ctx = zlib_compress_init();
3560 logevent("Initialised zlib (RFC1950) compression");
3561 ssh->sc_comp_ctx = zlib_decompress_init();
3562 logevent("Initialised zlib (RFC1950) decompression");
3563 }
3564
3565 /*
3566 * Start the shell or command.
3567 *
3568 * Special case: if the first-choice command is an SSH2
3569 * subsystem (hence not usable here) and the second choice
3570 * exists, we fall straight back to that.
3571 */
3572 {
3573 char *cmd = ssh->cfg.remote_cmd_ptr;
3574
3575 if (ssh->cfg.ssh_subsys && ssh->cfg.remote_cmd_ptr2) {
3576 cmd = ssh->cfg.remote_cmd_ptr2;
3577 ssh->fallback_cmd = TRUE;
3578 }
3579 if (*cmd)
3580 send_packet(ssh, SSH1_CMSG_EXEC_CMD, PKT_STR, cmd, PKT_END);
3581 else
3582 send_packet(ssh, SSH1_CMSG_EXEC_SHELL, PKT_END);
3583 logevent("Started session");
3584 }
3585
3586 ssh->state = SSH_STATE_SESSION;
3587 if (ssh->size_needed)
3588 ssh_size(ssh, ssh->term_width, ssh->term_height);
3589 if (ssh->eof_needed)
3590 ssh_special(ssh, TS_EOF);
3591
3592 if (ssh->ldisc)
3593 ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */
3594 ssh->send_ok = 1;
3595 ssh->channels = newtree234(ssh_channelcmp);
3596 while (1) {
3597 crReturnV;
3598 if (ispkt) {
3599 if (ssh->pktin.type == SSH1_SMSG_STDOUT_DATA ||
3600 ssh->pktin.type == SSH1_SMSG_STDERR_DATA) {
3601 char *string;
3602 int stringlen, bufsize;
3603
3604 ssh_pkt_getstring(ssh, &string, &stringlen);
3605 if (string == NULL) {
3606 bombout(("Incoming terminal data packet was badly formed"));
3607 crStopV;
3608 }
3609
3610 bufsize =
3611 from_backend(ssh->frontend,
3612 ssh->pktin.type == SSH1_SMSG_STDERR_DATA,
3613 string, stringlen);
3614 if (!ssh->v1_stdout_throttling && bufsize > SSH1_BUFFER_LIMIT) {
3615 ssh->v1_stdout_throttling = 1;
3616 ssh1_throttle(ssh, +1);
3617 }
3618 } else if (ssh->pktin.type == SSH1_MSG_DISCONNECT) {
3619 ssh_closing((Plug)ssh, NULL, 0, 0);
3620 logevent("Received disconnect request");
3621 crStopV;
3622 } else if (ssh->pktin.type == SSH1_SMSG_X11_OPEN) {
3623 /* Remote side is trying to open a channel to talk to our
3624 * X-Server. Give them back a local channel number. */
3625 struct ssh_channel *c;
3626 int remoteid = ssh_pkt_getuint32(ssh);
3627
3628 logevent("Received X11 connect request");
3629 /* Refuse if X11 forwarding is disabled. */
3630 if (!ssh->X11_fwd_enabled) {
3631 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3632 PKT_INT, remoteid, PKT_END);
3633 logevent("Rejected X11 connect request");
3634 } else {
3635 c = snew(struct ssh_channel);
3636 c->ssh = ssh;
3637
3638 if (x11_init(&c->u.x11.s, ssh->cfg.x11_display, c,
3639 ssh->x11auth, NULL, -1, &ssh->cfg) != NULL) {
3640 logevent("Opening X11 forward connection failed");
3641 sfree(c);
3642 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3643 PKT_INT, remoteid, PKT_END);
3644 } else {
3645 logevent
3646 ("Opening X11 forward connection succeeded");
3647 c->remoteid = remoteid;
3648 c->localid = alloc_channel_id(ssh);
3649 c->closes = 0;
3650 c->v.v1.throttling = 0;
3651 c->type = CHAN_X11; /* identify channel type */
3652 add234(ssh->channels, c);
3653 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3654 PKT_INT, c->remoteid, PKT_INT,
3655 c->localid, PKT_END);
3656 logevent("Opened X11 forward channel");
3657 }
3658 }
3659 } else if (ssh->pktin.type == SSH1_SMSG_AGENT_OPEN) {
3660 /* Remote side is trying to open a channel to talk to our
3661 * agent. Give them back a local channel number. */
3662 struct ssh_channel *c;
3663 int remoteid = ssh_pkt_getuint32(ssh);
3664
3665 /* Refuse if agent forwarding is disabled. */
3666 if (!ssh->agentfwd_enabled) {
3667 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3668 PKT_INT, remoteid, PKT_END);
3669 } else {
3670 c = snew(struct ssh_channel);
3671 c->ssh = ssh;
3672 c->remoteid = remoteid;
3673 c->localid = alloc_channel_id(ssh);
3674 c->closes = 0;
3675 c->v.v1.throttling = 0;
3676 c->type = CHAN_AGENT; /* identify channel type */
3677 c->u.a.lensofar = 0;
3678 add234(ssh->channels, c);
3679 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3680 PKT_INT, c->remoteid, PKT_INT, c->localid,
3681 PKT_END);
3682 }
3683 } else if (ssh->pktin.type == SSH1_MSG_PORT_OPEN) {
3684 /* Remote side is trying to open a channel to talk to a
3685 * forwarded port. Give them back a local channel number. */
3686 struct ssh_channel *c;
3687 struct ssh_rportfwd pf;
3688 int remoteid;
3689 int hostsize, port;
3690 char *host, buf[1024];
3691 const char *e;
3692 c = snew(struct ssh_channel);
3693 c->ssh = ssh;
3694
3695 remoteid = ssh_pkt_getuint32(ssh);
3696 ssh_pkt_getstring(ssh, &host, &hostsize);
3697 port = ssh_pkt_getuint32(ssh);
3698
3699 if (hostsize >= lenof(pf.dhost))
3700 hostsize = lenof(pf.dhost)-1;
3701 memcpy(pf.dhost, host, hostsize);
3702 pf.dhost[hostsize] = '\0';
3703 pf.dport = port;
3704
3705 if (find234(ssh->rportfwds, &pf, NULL) == NULL) {
3706 sprintf(buf, "Rejected remote port open request for %s:%d",
3707 pf.dhost, port);
3708 logevent(buf);
3709 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3710 PKT_INT, remoteid, PKT_END);
3711 } else {
3712 sprintf(buf, "Received remote port open request for %s:%d",
3713 pf.dhost, port);
3714 logevent(buf);
3715 e = pfd_newconnect(&c->u.pfd.s, pf.dhost, port,
3716 c, &ssh->cfg);
3717 if (e != NULL) {
3718 char buf[256];
3719 sprintf(buf, "Port open failed: %s", e);
3720 logevent(buf);
3721 sfree(c);
3722 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3723 PKT_INT, remoteid, PKT_END);
3724 } else {
3725 c->remoteid = remoteid;
3726 c->localid = alloc_channel_id(ssh);
3727 c->closes = 0;
3728 c->v.v1.throttling = 0;
3729 c->type = CHAN_SOCKDATA; /* identify channel type */
3730 add234(ssh->channels, c);
3731 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3732 PKT_INT, c->remoteid, PKT_INT,
3733 c->localid, PKT_END);
3734 logevent("Forwarded port opened successfully");
3735 }
3736 }
3737
3738 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_OPEN_CONFIRMATION) {
3739 unsigned int remoteid = ssh_pkt_getuint32(ssh);
3740 unsigned int localid = ssh_pkt_getuint32(ssh);
3741 struct ssh_channel *c;
3742
3743 c = find234(ssh->channels, &remoteid, ssh_channelfind);
3744 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
3745 c->remoteid = localid;
3746 c->type = CHAN_SOCKDATA;
3747 c->v.v1.throttling = 0;
3748 pfd_confirm(c->u.pfd.s);
3749 }
3750
3751 if (c && c->closes) {
3752 /*
3753 * We have a pending close on this channel,
3754 * which we decided on before the server acked
3755 * the channel open. So now we know the
3756 * remoteid, we can close it again.
3757 */
3758 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE,
3759 PKT_INT, c->remoteid, PKT_END);
3760 }
3761
3762 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_OPEN_FAILURE) {
3763 unsigned int remoteid = ssh_pkt_getuint32(ssh);
3764 struct ssh_channel *c;
3765
3766 c = find234(ssh->channels, &remoteid, ssh_channelfind);
3767 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
3768 logevent("Forwarded connection refused by server");
3769 pfd_close(c->u.pfd.s);
3770 del234(ssh->channels, c);
3771 sfree(c);
3772 }
3773
3774 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ||
3775 ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION) {
3776 /* Remote side closes a channel. */
3777 unsigned i = ssh_pkt_getuint32(ssh);
3778 struct ssh_channel *c;
3779 c = find234(ssh->channels, &i, ssh_channelfind);
3780 if (c && ((int)c->remoteid) != -1) {
3781 int closetype;
3782 closetype =
3783 (ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ? 1 : 2);
3784
3785 if ((c->closes == 0) && (c->type == CHAN_X11)) {
3786 logevent("Forwarded X11 connection terminated");
3787 assert(c->u.x11.s != NULL);
3788 x11_close(c->u.x11.s);
3789 c->u.x11.s = NULL;
3790 }
3791 if ((c->closes == 0) && (c->type == CHAN_SOCKDATA)) {
3792 logevent("Forwarded port closed");
3793 assert(c->u.pfd.s != NULL);
3794 pfd_close(c->u.pfd.s);
3795 c->u.pfd.s = NULL;
3796 }
3797
3798 c->closes |= (closetype << 2); /* seen this message */
3799 if (!(c->closes & closetype)) {
3800 send_packet(ssh, ssh->pktin.type, PKT_INT, c->remoteid,
3801 PKT_END);
3802 c->closes |= closetype; /* sent it too */
3803 }
3804
3805 if (c->closes == 15) {
3806 del234(ssh->channels, c);
3807 sfree(c);
3808 }
3809 } else {
3810 bombout(("Received CHANNEL_CLOSE%s for %s channel %d\n",
3811 ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ? "" :
3812 "_CONFIRMATION", c ? "half-open" : "nonexistent",
3813 i));
3814 crStopV;
3815 }
3816 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_DATA) {
3817 /* Data sent down one of our channels. */
3818 int i = ssh_pkt_getuint32(ssh);
3819 char *p;
3820 int len;
3821 struct ssh_channel *c;
3822
3823 ssh_pkt_getstring(ssh, &p, &len);
3824
3825 c = find234(ssh->channels, &i, ssh_channelfind);
3826 if (c) {
3827 int bufsize = 0;
3828 switch (c->type) {
3829 case CHAN_X11:
3830 bufsize = x11_send(c->u.x11.s, p, len);
3831 break;
3832 case CHAN_SOCKDATA:
3833 bufsize = pfd_send(c->u.pfd.s, p, len);
3834 break;
3835 case CHAN_AGENT:
3836 /* Data for an agent message. Buffer it. */
3837 while (len > 0) {
3838 if (c->u.a.lensofar < 4) {
3839 int l = min(4 - c->u.a.lensofar, len);
3840 memcpy(c->u.a.msglen + c->u.a.lensofar, p,
3841 l);
3842 p += l;
3843 len -= l;
3844 c->u.a.lensofar += l;
3845 }
3846 if (c->u.a.lensofar == 4) {
3847 c->u.a.totallen =
3848 4 + GET_32BIT(c->u.a.msglen);
3849 c->u.a.message = snewn(c->u.a.totallen,
3850 unsigned char);
3851 memcpy(c->u.a.message, c->u.a.msglen, 4);
3852 }
3853 if (c->u.a.lensofar >= 4 && len > 0) {
3854 int l =
3855 min(c->u.a.totallen - c->u.a.lensofar,
3856 len);
3857 memcpy(c->u.a.message + c->u.a.lensofar, p,
3858 l);
3859 p += l;
3860 len -= l;
3861 c->u.a.lensofar += l;
3862 }
3863 if (c->u.a.lensofar == c->u.a.totallen) {
3864 void *reply;
3865 int replylen;
3866 if (agent_query(c->u.a.message,
3867 c->u.a.totallen,
3868 &reply, &replylen,
3869 ssh_agentf_callback, c))
3870 ssh_agentf_callback(c, reply, replylen);
3871 sfree(c->u.a.message);
3872 c->u.a.lensofar = 0;
3873 }
3874 }
3875 bufsize = 0; /* agent channels never back up */
3876 break;
3877 }
3878 if (!c->v.v1.throttling && bufsize > SSH1_BUFFER_LIMIT) {
3879 c->v.v1.throttling = 1;
3880 ssh1_throttle(ssh, +1);
3881 }
3882 }
3883 } else if (ssh->pktin.type == SSH1_SMSG_SUCCESS) {
3884 /* may be from EXEC_SHELL on some servers */
3885 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3886 /* may be from EXEC_SHELL on some servers
3887 * if no pty is available or in other odd cases. Ignore */
3888 } else if (ssh->pktin.type == SSH1_SMSG_EXIT_STATUS) {
3889 char buf[100];
3890 ssh->exitcode = ssh_pkt_getuint32(ssh);
3891 sprintf(buf, "Server sent command exit status %d",
3892 ssh->exitcode);
3893 logevent(buf);
3894 send_packet(ssh, SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
3895 /*
3896 * In case `helpful' firewalls or proxies tack
3897 * extra human-readable text on the end of the
3898 * session which we might mistake for another
3899 * encrypted packet, we close the session once
3900 * we've sent EXIT_CONFIRMATION.
3901 */
3902 ssh_closing((Plug)ssh, NULL, 0, 0);
3903 crStopV;
3904 } else {
3905 bombout(("Strange packet received: type %d", ssh->pktin.type));
3906 crStopV;
3907 }
3908 } else {
3909 while (inlen > 0) {
3910 int len = min(inlen, 512);
3911 send_packet(ssh, SSH1_CMSG_STDIN_DATA,
3912 PKT_INT, len, PKT_DATA, in, len, PKT_END);
3913 in += len;
3914 inlen -= len;
3915 }
3916 }
3917 }
3918
3919 crFinishV;
3920 }
3921
3922 /*
3923 * Utility routine for decoding comma-separated strings in KEXINIT.
3924 */
3925 static int in_commasep_string(char *needle, char *haystack, int haylen)
3926 {
3927 int needlen;
3928 if (!needle || !haystack) /* protect against null pointers */
3929 return 0;
3930 needlen = strlen(needle);
3931 while (1) {
3932 /*
3933 * Is it at the start of the string?
3934 */
3935 if (haylen >= needlen && /* haystack is long enough */
3936 !memcmp(needle, haystack, needlen) && /* initial match */
3937 (haylen == needlen || haystack[needlen] == ',')
3938 /* either , or EOS follows */
3939 )
3940 return 1;
3941 /*
3942 * If not, search for the next comma and resume after that.
3943 * If no comma found, terminate.
3944 */
3945 while (haylen > 0 && *haystack != ',')
3946 haylen--, haystack++;
3947 if (haylen == 0)
3948 return 0;
3949 haylen--, haystack++; /* skip over comma itself */
3950 }
3951 }
3952
3953 /*
3954 * SSH2 key creation method.
3955 */
3956 static void ssh2_mkkey(Ssh ssh, Bignum K, unsigned char *H,
3957 unsigned char *sessid, char chr,
3958 unsigned char *keyspace)
3959 {
3960 SHA_State s;
3961 /* First 20 bytes. */
3962 SHA_Init(&s);
3963 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
3964 sha_mpint(&s, K);
3965 SHA_Bytes(&s, H, 20);
3966 SHA_Bytes(&s, &chr, 1);
3967 SHA_Bytes(&s, sessid, 20);
3968 SHA_Final(&s, keyspace);
3969 /* Next 20 bytes. */
3970 SHA_Init(&s);
3971 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
3972 sha_mpint(&s, K);
3973 SHA_Bytes(&s, H, 20);
3974 SHA_Bytes(&s, keyspace, 20);
3975 SHA_Final(&s, keyspace + 20);
3976 }
3977
3978 /*
3979 * Handle the SSH2 transport layer.
3980 */
3981 static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
3982 {
3983 struct do_ssh2_transport_state {
3984 int nbits, pbits, warn;
3985 Bignum p, g, e, f, K;
3986 int kex_init_value, kex_reply_value;
3987 const struct ssh_mac **maclist;
3988 int nmacs;
3989 const struct ssh2_cipher *cscipher_tobe;
3990 const struct ssh2_cipher *sccipher_tobe;
3991 const struct ssh_mac *csmac_tobe;
3992 const struct ssh_mac *scmac_tobe;
3993 const struct ssh_compress *cscomp_tobe;
3994 const struct ssh_compress *sccomp_tobe;
3995 char *hostkeydata, *sigdata, *keystr, *fingerprint;
3996 int hostkeylen, siglen;
3997 void *hkey; /* actual host key */
3998 unsigned char exchange_hash[20];
3999 int n_preferred_ciphers;
4000 const struct ssh2_ciphers *preferred_ciphers[CIPHER_MAX];
4001 const struct ssh_compress *preferred_comp;
4002 int first_kex;
4003 };
4004 crState(do_ssh2_transport_state);
4005
4006 crBegin(ssh->do_ssh2_transport_crstate);
4007
4008 s->cscipher_tobe = s->sccipher_tobe = NULL;
4009 s->csmac_tobe = s->scmac_tobe = NULL;
4010 s->cscomp_tobe = s->sccomp_tobe = NULL;
4011
4012 random_init();
4013 s->first_kex = 1;
4014
4015 {
4016 int i;
4017 /*
4018 * Set up the preferred ciphers. (NULL => warn below here)
4019 */
4020 s->n_preferred_ciphers = 0;
4021 for (i = 0; i < CIPHER_MAX; i++) {
4022 switch (ssh->cfg.ssh_cipherlist[i]) {
4023 case CIPHER_BLOWFISH:
4024 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_blowfish;
4025 break;
4026 case CIPHER_DES:
4027 if (ssh->cfg.ssh2_des_cbc) {
4028 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_des;
4029 }
4030 break;
4031 case CIPHER_3DES:
4032 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_3des;
4033 break;
4034 case CIPHER_AES:
4035 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_aes;
4036 break;
4037 case CIPHER_WARN:
4038 /* Flag for later. Don't bother if it's the last in
4039 * the list. */
4040 if (i < CIPHER_MAX - 1) {
4041 s->preferred_ciphers[s->n_preferred_ciphers++] = NULL;
4042 }
4043 break;
4044 }
4045 }
4046 }
4047
4048 /*
4049 * Set up preferred compression.
4050 */
4051 if (ssh->cfg.compression)
4052 s->preferred_comp = &ssh_zlib;
4053 else
4054 s->preferred_comp = &ssh_comp_none;
4055
4056 /*
4057 * Be prepared to work around the buggy MAC problem.
4058 */
4059 if (ssh->remote_bugs & BUG_SSH2_HMAC)
4060 s->maclist = buggymacs, s->nmacs = lenof(buggymacs);
4061 else
4062 s->maclist = macs, s->nmacs = lenof(macs);
4063
4064 begin_key_exchange:
4065 {
4066 int i, j, cipherstr_started;
4067
4068 /*
4069 * Construct and send our key exchange packet.
4070 */
4071 ssh2_pkt_init(ssh, SSH2_MSG_KEXINIT);
4072 for (i = 0; i < 16; i++)
4073 ssh2_pkt_addbyte(ssh, (unsigned char) random_byte());
4074 /* List key exchange algorithms. */
4075 ssh2_pkt_addstring_start(ssh);
4076 for (i = 0; i < lenof(kex_algs); i++) {
4077 if (kex_algs[i] == &ssh_diffiehellman_gex &&
4078 (ssh->remote_bugs & BUG_SSH2_DH_GEX))
4079 continue;
4080 ssh2_pkt_addstring_str(ssh, kex_algs[i]->name);
4081 if (i < lenof(kex_algs) - 1)
4082 ssh2_pkt_addstring_str(ssh, ",");
4083 }
4084 /* List server host key algorithms. */
4085 ssh2_pkt_addstring_start(ssh);
4086 for (i = 0; i < lenof(hostkey_algs); i++) {
4087 ssh2_pkt_addstring_str(ssh, hostkey_algs[i]->name);
4088 if (i < lenof(hostkey_algs) - 1)
4089 ssh2_pkt_addstring_str(ssh, ",");
4090 }
4091 /* List client->server encryption algorithms. */
4092 ssh2_pkt_addstring_start(ssh);
4093 cipherstr_started = 0;
4094 for (i = 0; i < s->n_preferred_ciphers; i++) {
4095 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
4096 if (!c) continue; /* warning flag */
4097 for (j = 0; j < c->nciphers; j++) {
4098 if (cipherstr_started)
4099 ssh2_pkt_addstring_str(ssh, ",");
4100 ssh2_pkt_addstring_str(ssh, c->list[j]->name);
4101 cipherstr_started = 1;
4102 }
4103 }
4104 /* List server->client encryption algorithms. */
4105 ssh2_pkt_addstring_start(ssh);
4106 cipherstr_started = 0;
4107 for (i = 0; i < s->n_preferred_ciphers; i++) {
4108 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
4109 if (!c) continue; /* warning flag */
4110 for (j = 0; j < c->nciphers; j++) {
4111 if (cipherstr_started)
4112 ssh2_pkt_addstring_str(ssh, ",");
4113 ssh2_pkt_addstring_str(ssh, c->list[j]->name);
4114 cipherstr_started = 1;
4115 }
4116 }
4117 /* List client->server MAC algorithms. */
4118 ssh2_pkt_addstring_start(ssh);
4119 for (i = 0; i < s->nmacs; i++) {
4120 ssh2_pkt_addstring_str(ssh, s->maclist[i]->name);
4121 if (i < s->nmacs - 1)
4122 ssh2_pkt_addstring_str(ssh, ",");
4123 }
4124 /* List server->client MAC algorithms. */
4125 ssh2_pkt_addstring_start(ssh);
4126 for (i = 0; i < s->nmacs; i++) {
4127 ssh2_pkt_addstring_str(ssh, s->maclist[i]->name);
4128 if (i < s->nmacs - 1)
4129 ssh2_pkt_addstring_str(ssh, ",");
4130 }
4131 /* List client->server compression algorithms. */
4132 ssh2_pkt_addstring_start(ssh);
4133 for (i = 0; i < lenof(compressions) + 1; i++) {
4134 const struct ssh_compress *c =
4135 i == 0 ? s->preferred_comp : compressions[i - 1];
4136 ssh2_pkt_addstring_str(ssh, c->name);
4137 if (i < lenof(compressions))
4138 ssh2_pkt_addstring_str(ssh, ",");
4139 }
4140 /* List server->client compression algorithms. */
4141 ssh2_pkt_addstring_start(ssh);
4142 for (i = 0; i < lenof(compressions) + 1; i++) {
4143 const struct ssh_compress *c =
4144 i == 0 ? s->preferred_comp : compressions[i - 1];
4145 ssh2_pkt_addstring_str(ssh, c->name);
4146 if (i < lenof(compressions))
4147 ssh2_pkt_addstring_str(ssh, ",");
4148 }
4149 /* List client->server languages. Empty list. */
4150 ssh2_pkt_addstring_start(ssh);
4151 /* List server->client languages. Empty list. */
4152 ssh2_pkt_addstring_start(ssh);
4153 /* First KEX packet does _not_ follow, because we're not that brave. */
4154 ssh2_pkt_addbool(ssh, FALSE);
4155 /* Reserved. */
4156 ssh2_pkt_adduint32(ssh, 0);
4157 }
4158
4159 ssh->exhash = ssh->exhashbase;
4160 sha_string(&ssh->exhash, ssh->pktout.data + 5, ssh->pktout.length - 5);
4161
4162 ssh2_pkt_send(ssh);
4163
4164 if (!ispkt)
4165 crWaitUntil(ispkt);
4166 if (ssh->pktin.length > 5)
4167 sha_string(&ssh->exhash, ssh->pktin.data + 5, ssh->pktin.length - 5);
4168
4169 /*
4170 * Now examine the other side's KEXINIT to see what we're up
4171 * to.
4172 */
4173 {
4174 char *str;
4175 int i, j, len;
4176
4177 if (ssh->pktin.type != SSH2_MSG_KEXINIT) {
4178 bombout(("expected key exchange packet from server"));
4179 crStop(0);
4180 }
4181 ssh->kex = NULL;
4182 ssh->hostkey = NULL;
4183 s->cscipher_tobe = NULL;
4184 s->sccipher_tobe = NULL;
4185 s->csmac_tobe = NULL;
4186 s->scmac_tobe = NULL;
4187 s->cscomp_tobe = NULL;
4188 s->sccomp_tobe = NULL;
4189 ssh->pktin.savedpos += 16; /* skip garbage cookie */
4190 ssh_pkt_getstring(ssh, &str, &len); /* key exchange algorithms */
4191 for (i = 0; i < lenof(kex_algs); i++) {
4192 if (kex_algs[i] == &ssh_diffiehellman_gex &&
4193 (ssh->remote_bugs & BUG_SSH2_DH_GEX))
4194 continue;
4195 if (in_commasep_string(kex_algs[i]->name, str, len)) {
4196 ssh->kex = kex_algs[i];
4197 break;
4198 }
4199 }
4200 ssh_pkt_getstring(ssh, &str, &len); /* host key algorithms */
4201 for (i = 0; i < lenof(hostkey_algs); i++) {
4202 if (in_commasep_string(hostkey_algs[i]->name, str, len)) {
4203 ssh->hostkey = hostkey_algs[i];
4204 break;
4205 }
4206 }
4207 ssh_pkt_getstring(ssh, &str, &len); /* client->server cipher */
4208 s->warn = 0;
4209 for (i = 0; i < s->n_preferred_ciphers; i++) {
4210 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
4211 if (!c) {
4212 s->warn = 1;
4213 } else {
4214 for (j = 0; j < c->nciphers; j++) {
4215 if (in_commasep_string(c->list[j]->name, str, len)) {
4216 s->cscipher_tobe = c->list[j];
4217 break;
4218 }
4219 }
4220 }
4221 if (s->cscipher_tobe) {
4222 if (s->warn)
4223 askcipher(ssh->frontend, s->cscipher_tobe->name, 1);
4224 break;
4225 }
4226 }
4227 if (!s->cscipher_tobe) {
4228 bombout(("Couldn't agree a client-to-server cipher (available: %s)",
4229 str ? str : "(null)"));
4230 crStop(0);
4231 }
4232
4233 ssh_pkt_getstring(ssh, &str, &len); /* server->client cipher */
4234 s->warn = 0;
4235 for (i = 0; i < s->n_preferred_ciphers; i++) {
4236 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
4237 if (!c) {
4238 s->warn = 1;
4239 } else {
4240 for (j = 0; j < c->nciphers; j++) {
4241 if (in_commasep_string(c->list[j]->name, str, len)) {
4242 s->sccipher_tobe = c->list[j];
4243 break;
4244 }
4245 }
4246 }
4247 if (s->sccipher_tobe) {
4248 if (s->warn)
4249 askcipher(ssh->frontend, s->sccipher_tobe->name, 2);
4250 break;
4251 }
4252 }
4253 if (!s->sccipher_tobe) {
4254 bombout(("Couldn't agree a server-to-client cipher (available: %s)",
4255 str ? str : "(null)"));
4256 crStop(0);
4257 }
4258
4259 ssh_pkt_getstring(ssh, &str, &len); /* client->server mac */
4260 for (i = 0; i < s->nmacs; i++) {
4261 if (in_commasep_string(s->maclist[i]->name, str, len)) {
4262 s->csmac_tobe = s->maclist[i];
4263 break;
4264 }
4265 }
4266 ssh_pkt_getstring(ssh, &str, &len); /* server->client mac */
4267 for (i = 0; i < s->nmacs; i++) {
4268 if (in_commasep_string(s->maclist[i]->name, str, len)) {
4269 s->scmac_tobe = s->maclist[i];
4270 break;
4271 }
4272 }
4273 ssh_pkt_getstring(ssh, &str, &len); /* client->server compression */
4274 for (i = 0; i < lenof(compressions) + 1; i++) {
4275 const struct ssh_compress *c =
4276 i == 0 ? s->preferred_comp : compressions[i - 1];
4277 if (in_commasep_string(c->name, str, len)) {
4278 s->cscomp_tobe = c;
4279 break;
4280 }
4281 }
4282 ssh_pkt_getstring(ssh, &str, &len); /* server->client compression */
4283 for (i = 0; i < lenof(compressions) + 1; i++) {
4284 const struct ssh_compress *c =
4285 i == 0 ? s->preferred_comp : compressions[i - 1];
4286 if (in_commasep_string(c->name, str, len)) {
4287 s->sccomp_tobe = c;
4288 break;
4289 }
4290 }
4291 }
4292
4293 /*
4294 * Work out the number of bits of key we will need from the key
4295 * exchange. We start with the maximum key length of either
4296 * cipher...
4297 */
4298 {
4299 int csbits, scbits;
4300
4301 csbits = s->cscipher_tobe->keylen;
4302 scbits = s->sccipher_tobe->keylen;
4303 s->nbits = (csbits > scbits ? csbits : scbits);
4304 }
4305 /* The keys only have 160-bit entropy, since they're based on
4306 * a SHA-1 hash. So cap the key size at 160 bits. */
4307 if (s->nbits > 160)
4308 s->nbits = 160;
4309
4310 /*
4311 * If we're doing Diffie-Hellman group exchange, start by
4312 * requesting a group.
4313 */
4314 if (ssh->kex == &ssh_diffiehellman_gex) {
4315 logevent("Doing Diffie-Hellman group exchange");
4316 ssh->pkt_ctx |= SSH2_PKTCTX_DHGEX;
4317 /*
4318 * Work out how big a DH group we will need to allow that
4319 * much data.
4320 */
4321 s->pbits = 512 << ((s->nbits - 1) / 64);
4322 ssh2_pkt_init(ssh, SSH2_MSG_KEX_DH_GEX_REQUEST);
4323 ssh2_pkt_adduint32(ssh, s->pbits);
4324 ssh2_pkt_send(ssh);
4325
4326 crWaitUntil(ispkt);
4327 if (ssh->pktin.type != SSH2_MSG_KEX_DH_GEX_GROUP) {
4328 bombout(("expected key exchange group packet from server"));
4329 crStop(0);
4330 }
4331 s->p = ssh2_pkt_getmp(ssh);
4332 s->g = ssh2_pkt_getmp(ssh);
4333 ssh->kex_ctx = dh_setup_group(s->p, s->g);
4334 s->kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT;
4335 s->kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY;
4336 } else {
4337 ssh->pkt_ctx |= SSH2_PKTCTX_DHGROUP1;
4338 ssh->kex_ctx = dh_setup_group1();
4339 s->kex_init_value = SSH2_MSG_KEXDH_INIT;
4340 s->kex_reply_value = SSH2_MSG_KEXDH_REPLY;
4341 }
4342
4343 logevent("Doing Diffie-Hellman key exchange");
4344 /*
4345 * Now generate and send e for Diffie-Hellman.
4346 */
4347 s->e = dh_create_e(ssh->kex_ctx, s->nbits * 2);
4348 ssh2_pkt_init(ssh, s->kex_init_value);
4349 ssh2_pkt_addmp(ssh, s->e);
4350 ssh2_pkt_send(ssh);
4351
4352 crWaitUntil(ispkt);
4353 if (ssh->pktin.type != s->kex_reply_value) {
4354 bombout(("expected key exchange reply packet from server"));
4355 crStop(0);
4356 }
4357 ssh_pkt_getstring(ssh, &s->hostkeydata, &s->hostkeylen);
4358 s->f = ssh2_pkt_getmp(ssh);
4359 ssh_pkt_getstring(ssh, &s->sigdata, &s->siglen);
4360
4361 s->K = dh_find_K(ssh->kex_ctx, s->f);
4362
4363 sha_string(&ssh->exhash, s->hostkeydata, s->hostkeylen);
4364 if (ssh->kex == &ssh_diffiehellman_gex) {
4365 sha_uint32(&ssh->exhash, s->pbits);
4366 sha_mpint(&ssh->exhash, s->p);
4367 sha_mpint(&ssh->exhash, s->g);
4368 }
4369 sha_mpint(&ssh->exhash, s->e);
4370 sha_mpint(&ssh->exhash, s->f);
4371 sha_mpint(&ssh->exhash, s->K);
4372 SHA_Final(&ssh->exhash, s->exchange_hash);
4373
4374 dh_cleanup(ssh->kex_ctx);
4375 ssh->kex_ctx = NULL;
4376
4377 #if 0
4378 debug(("Exchange hash is:\n"));
4379 dmemdump(s->exchange_hash, 20);
4380 #endif
4381
4382 s->hkey = ssh->hostkey->newkey(s->hostkeydata, s->hostkeylen);
4383 if (!s->hkey ||
4384 !ssh->hostkey->verifysig(s->hkey, s->sigdata, s->siglen,
4385 (char *)s->exchange_hash, 20)) {
4386 bombout(("Server's host key did not match the signature supplied"));
4387 crStop(0);
4388 }
4389
4390 /*
4391 * Authenticate remote host: verify host key. (We've already
4392 * checked the signature of the exchange hash.)
4393 */
4394 s->keystr = ssh->hostkey->fmtkey(s->hkey);
4395 s->fingerprint = ssh->hostkey->fingerprint(s->hkey);
4396 verify_ssh_host_key(ssh->frontend,
4397 ssh->savedhost, ssh->savedport, ssh->hostkey->keytype,
4398 s->keystr, s->fingerprint);
4399 if (s->first_kex) { /* don't bother logging this in rekeys */
4400 logevent("Host key fingerprint is:");
4401 logevent(s->fingerprint);
4402 }
4403 sfree(s->fingerprint);
4404 sfree(s->keystr);
4405 ssh->hostkey->freekey(s->hkey);
4406
4407 /*
4408 * Send SSH2_MSG_NEWKEYS.
4409 */
4410 ssh2_pkt_init(ssh, SSH2_MSG_NEWKEYS);
4411 ssh2_pkt_send(ssh);
4412
4413 /*
4414 * Expect SSH2_MSG_NEWKEYS from server.
4415 */
4416 crWaitUntil(ispkt);
4417 if (ssh->pktin.type != SSH2_MSG_NEWKEYS) {
4418 bombout(("expected new-keys packet from server"));
4419 crStop(0);
4420 }
4421
4422 /*
4423 * Create and initialise session keys.
4424 */
4425 if (ssh->cs_cipher_ctx)
4426 ssh->cscipher->free_context(ssh->cs_cipher_ctx);
4427 ssh->cscipher = s->cscipher_tobe;
4428 ssh->cs_cipher_ctx = ssh->cscipher->make_context();
4429
4430 if (ssh->sc_cipher_ctx)
4431 ssh->sccipher->free_context(ssh->sc_cipher_ctx);
4432 ssh->sccipher = s->sccipher_tobe;
4433 ssh->sc_cipher_ctx = ssh->sccipher->make_context();
4434
4435 if (ssh->cs_mac_ctx)
4436 ssh->csmac->free_context(ssh->cs_mac_ctx);
4437 ssh->csmac = s->csmac_tobe;
4438 ssh->cs_mac_ctx = ssh->csmac->make_context();
4439
4440 if (ssh->sc_mac_ctx)
4441 ssh->scmac->free_context(ssh->sc_mac_ctx);
4442 ssh->scmac = s->scmac_tobe;
4443 ssh->sc_mac_ctx = ssh->scmac->make_context();
4444
4445 if (ssh->cs_comp_ctx)
4446 ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
4447 ssh->cscomp = s->cscomp_tobe;
4448 ssh->cs_comp_ctx = ssh->cscomp->compress_init();
4449
4450 if (ssh->sc_comp_ctx)
4451 ssh->sccomp->decompress_cleanup(ssh->sc_comp_ctx);
4452 ssh->sccomp = s->sccomp_tobe;
4453 ssh->sc_comp_ctx = ssh->sccomp->decompress_init();
4454
4455 /*
4456 * Set IVs after keys. Here we use the exchange hash from the
4457 * _first_ key exchange.
4458 */
4459 {
4460 unsigned char keyspace[40];
4461 if (s->first_kex)
4462 memcpy(ssh->v2_session_id, s->exchange_hash,
4463 sizeof(s->exchange_hash));
4464 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'C',keyspace);
4465 ssh->cscipher->setkey(ssh->cs_cipher_ctx, keyspace);
4466 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'D',keyspace);
4467 ssh->sccipher->setkey(ssh->sc_cipher_ctx, keyspace);
4468 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'A',keyspace);
4469 ssh->cscipher->setiv(ssh->cs_cipher_ctx, keyspace);
4470 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'B',keyspace);
4471 ssh->sccipher->setiv(ssh->sc_cipher_ctx, keyspace);
4472 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'E',keyspace);
4473 ssh->csmac->setkey(ssh->cs_mac_ctx, keyspace);
4474 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'F',keyspace);
4475 ssh->scmac->setkey(ssh->sc_mac_ctx, keyspace);
4476 }
4477 logeventf(ssh, "Initialised %.200s client->server encryption",
4478 ssh->cscipher->text_name);
4479 logeventf(ssh, "Initialised %.200s server->client encryption",
4480 ssh->sccipher->text_name);
4481 if (ssh->cscomp->text_name)
4482 logeventf(ssh, "Initialised %s compression",
4483 ssh->cscomp->text_name);
4484 if (ssh->sccomp->text_name)
4485 logeventf(ssh, "Initialised %s decompression",
4486 ssh->sccomp->text_name);
4487 freebn(s->f);
4488 freebn(s->K);
4489 if (ssh->kex == &ssh_diffiehellman_gex) {
4490 freebn(s->g);
4491 freebn(s->p);
4492 }
4493
4494 /*
4495 * If this is the first key exchange phase, we must pass the
4496 * SSH2_MSG_NEWKEYS packet to the next layer, not because it
4497 * wants to see it but because it will need time to initialise
4498 * itself before it sees an actual packet. In subsequent key
4499 * exchange phases, we don't pass SSH2_MSG_NEWKEYS on, because
4500 * it would only confuse the layer above.
4501 */
4502 if (!s->first_kex) {
4503 crReturn(0);
4504 }
4505 s->first_kex = 0;
4506
4507 /*
4508 * Now we're encrypting. Begin returning 1 to the protocol main
4509 * function so that other things can run on top of the
4510 * transport. If we ever see a KEXINIT, we must go back to the
4511 * start.
4512 */
4513 while (!(ispkt && ssh->pktin.type == SSH2_MSG_KEXINIT)) {
4514 crReturn(1);
4515 }
4516 logevent("Server initiated key re-exchange");
4517 goto begin_key_exchange;
4518
4519 crFinish(1);
4520 }
4521
4522 /*
4523 * Add data to an SSH2 channel output buffer.
4524 */
4525 static void ssh2_add_channel_data(struct ssh_channel *c, char *buf,
4526 int len)
4527 {
4528 bufchain_add(&c->v.v2.outbuffer, buf, len);
4529 }
4530
4531 /*
4532 * Attempt to send data on an SSH2 channel.
4533 */
4534 static int ssh2_try_send(struct ssh_channel *c)
4535 {
4536 Ssh ssh = c->ssh;
4537
4538 while (c->v.v2.remwindow > 0 && bufchain_size(&c->v.v2.outbuffer) > 0) {
4539 int len;
4540 void *data;
4541 bufchain_prefix(&c->v.v2.outbuffer, &data, &len);
4542 if ((unsigned)len > c->v.v2.remwindow)
4543 len = c->v.v2.remwindow;
4544 if ((unsigned)len > c->v.v2.remmaxpkt)
4545 len = c->v.v2.remmaxpkt;
4546 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_DATA);
4547 ssh2_pkt_adduint32(ssh, c->remoteid);
4548 ssh2_pkt_addstring_start(ssh);
4549 ssh2_pkt_addstring_data(ssh, data, len);
4550 ssh2_pkt_send(ssh);
4551 bufchain_consume(&c->v.v2.outbuffer, len);
4552 c->v.v2.remwindow -= len;
4553 }
4554
4555 /*
4556 * After having sent as much data as we can, return the amount
4557 * still buffered.
4558 */
4559 return bufchain_size(&c->v.v2.outbuffer);
4560 }
4561
4562 /*
4563 * Potentially enlarge the window on an SSH2 channel.
4564 */
4565 static void ssh2_set_window(struct ssh_channel *c, unsigned newwin)
4566 {
4567 Ssh ssh = c->ssh;
4568
4569 /*
4570 * Never send WINDOW_ADJUST for a channel that the remote side
4571 * already thinks it's closed; there's no point, since it won't
4572 * be sending any more data anyway.
4573 */
4574 if (c->closes != 0)
4575 return;
4576
4577 if (newwin > c->v.v2.locwindow) {
4578 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST);
4579 ssh2_pkt_adduint32(ssh, c->remoteid);
4580 ssh2_pkt_adduint32(ssh, newwin - c->v.v2.locwindow);
4581 ssh2_pkt_send(ssh);
4582 c->v.v2.locwindow = newwin;
4583 }
4584 }
4585
4586 /*
4587 * Handle the SSH2 userauth and connection layers.
4588 */
4589 static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
4590 {
4591 struct do_ssh2_authconn_state {
4592 enum {
4593 AUTH_INVALID, AUTH_PUBLICKEY_AGENT, AUTH_PUBLICKEY_FILE,
4594 AUTH_PASSWORD,
4595 AUTH_KEYBOARD_INTERACTIVE
4596 } method;
4597 enum {
4598 AUTH_TYPE_NONE,
4599 AUTH_TYPE_PUBLICKEY,
4600 AUTH_TYPE_PUBLICKEY_OFFER_LOUD,
4601 AUTH_TYPE_PUBLICKEY_OFFER_QUIET,
4602 AUTH_TYPE_PASSWORD,
4603 AUTH_TYPE_KEYBOARD_INTERACTIVE,
4604 AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET
4605 } type;
4606 int gotit, need_pw, can_pubkey, can_passwd, can_keyb_inter;
4607 int tried_pubkey_config, tried_agent, tried_keyb_inter;
4608 int kbd_inter_running;
4609 int we_are_in;
4610 int num_prompts, curr_prompt, echo;
4611 char username[100];
4612 int got_username;
4613 char pwprompt[200];
4614 char password[100];
4615 void *publickey_blob;
4616 int publickey_bloblen;
4617 unsigned char request[5], *response, *p;
4618 int responselen;
4619 int keyi, nkeys;
4620 int authed;
4621 char *pkblob, *alg, *commentp;
4622 int pklen, alglen, commentlen;
4623 int siglen, retlen, len;
4624 char *q, *agentreq, *ret;
4625 int try_send;
4626 };
4627 crState(do_ssh2_authconn_state);
4628
4629 crBegin(ssh->do_ssh2_authconn_crstate);
4630
4631 /*
4632 * Request userauth protocol, and await a response to it.
4633 */
4634 ssh2_pkt_init(ssh, SSH2_MSG_SERVICE_REQUEST);
4635 ssh2_pkt_addstring(ssh, "ssh-userauth");
4636 ssh2_pkt_send(ssh);
4637 crWaitUntilV(ispkt);
4638 if (ssh->pktin.type != SSH2_MSG_SERVICE_ACCEPT) {
4639 bombout(("Server refused user authentication protocol"));
4640 crStopV;
4641 }
4642
4643 /*
4644 * We repeat this whole loop, including the username prompt,
4645 * until we manage a successful authentication. If the user
4646 * types the wrong _password_, they can be sent back to the
4647 * beginning to try another username, if this is configured on.
4648 * (If they specify a username in the config, they are never
4649 * asked, even if they do give a wrong password.)
4650 *
4651 * I think this best serves the needs of
4652 *
4653 * - the people who have no configuration, no keys, and just
4654 * want to try repeated (username,password) pairs until they
4655 * type both correctly
4656 *
4657 * - people who have keys and configuration but occasionally
4658 * need to fall back to passwords
4659 *
4660 * - people with a key held in Pageant, who might not have
4661 * logged in to a particular machine before; so they want to
4662 * type a username, and then _either_ their key will be
4663 * accepted, _or_ they will type a password. If they mistype
4664 * the username they will want to be able to get back and
4665 * retype it!
4666 */
4667 s->username[0] = '\0';
4668 s->got_username = FALSE;
4669 do {
4670 /*
4671 * Get a username.
4672 */
4673 if (s->got_username && !ssh->cfg.change_username) {
4674 /*
4675 * We got a username last time round this loop, and
4676 * with change_username turned off we don't try to get
4677 * it again.
4678 */
4679 } else if ((flags & FLAG_INTERACTIVE) && !*ssh->cfg.username) {
4680 if (ssh_get_line && !ssh_getline_pw_only) {
4681 if (!ssh_get_line("login as: ",
4682 s->username, sizeof(s->username), FALSE)) {
4683 /*
4684 * get_line failed to get a username.
4685 * Terminate.
4686 */
4687 logevent("No username provided. Abandoning session.");
4688 ssh_closing((Plug)ssh, NULL, 0, 0);
4689 crStopV;
4690 }
4691 } else {
4692 int ret; /* need not be saved across crReturn */
4693 c_write_str(ssh, "login as: ");
4694 ssh->send_ok = 1;
4695 setup_userpass_input(ssh, s->username, sizeof(s->username), 1);
4696 do {
4697 crWaitUntilV(!ispkt);
4698 ret = process_userpass_input(ssh, in, inlen);
4699 } while (ret == 0);
4700 if (ret < 0)
4701 cleanup_exit(0);
4702 c_write_str(ssh, "\r\n");
4703 }
4704 s->username[strcspn(s->username, "\n\r")] = '\0';
4705 } else {
4706 char *stuff;
4707 strncpy(s->username, ssh->cfg.username, sizeof(s->username));
4708 s->username[sizeof(s->username)-1] = '\0';
4709 if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
4710 stuff = dupprintf("Using username \"%s\".\r\n", s->username);
4711 c_write_str(ssh, stuff);
4712 sfree(stuff);
4713 }
4714 }
4715 s->got_username = TRUE;
4716
4717 /*
4718 * Send an authentication request using method "none": (a)
4719 * just in case it succeeds, and (b) so that we know what
4720 * authentication methods we can usefully try next.
4721 */
4722 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4723
4724 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4725 ssh2_pkt_addstring(ssh, s->username);
4726 ssh2_pkt_addstring(ssh, "ssh-connection");/* service requested */
4727 ssh2_pkt_addstring(ssh, "none"); /* method */
4728 ssh2_pkt_send(ssh);
4729 s->type = AUTH_TYPE_NONE;
4730 s->gotit = FALSE;
4731 s->we_are_in = FALSE;
4732
4733 s->tried_pubkey_config = FALSE;
4734 s->tried_agent = FALSE;
4735 s->tried_keyb_inter = FALSE;
4736 s->kbd_inter_running = FALSE;
4737 /* Load the pub half of ssh->cfg.keyfile so we notice if it's in Pageant */
4738 if (!filename_is_null(ssh->cfg.keyfile)) {
4739 int keytype;
4740 logeventf(ssh, "Reading private key file \"%.150s\"",
4741 filename_to_str(&ssh->cfg.keyfile));
4742 keytype = key_type(&ssh->cfg.keyfile);
4743 if (keytype == SSH_KEYTYPE_SSH2) {
4744 s->publickey_blob =
4745 ssh2_userkey_loadpub(&ssh->cfg.keyfile, NULL,
4746 &s->publickey_bloblen, NULL);
4747 } else {
4748 char *msgbuf;
4749 logeventf(ssh, "Unable to use this key file (%s)",
4750 key_type_to_str(keytype));
4751 msgbuf = dupprintf("Unable to use key file \"%.150s\""
4752 " (%s)\r\n",
4753 filename_to_str(&ssh->cfg.keyfile),
4754 key_type_to_str(keytype));
4755 c_write_str(ssh, msgbuf);
4756 sfree(msgbuf);
4757 s->publickey_blob = NULL;
4758 }
4759 } else
4760 s->publickey_blob = NULL;
4761
4762 while (1) {
4763 /*
4764 * Wait for the result of the last authentication request.
4765 */
4766 if (!s->gotit)
4767 crWaitUntilV(ispkt);
4768 while (ssh->pktin.type == SSH2_MSG_USERAUTH_BANNER) {
4769 char *banner;
4770 int size;
4771 /*
4772 * Don't show the banner if we're operating in
4773 * non-verbose non-interactive mode. (It's probably
4774 * a script, which means nobody will read the
4775 * banner _anyway_, and moreover the printing of
4776 * the banner will screw up processing on the
4777 * output of (say) plink.)
4778 */
4779 if (flags & (FLAG_VERBOSE | FLAG_INTERACTIVE)) {
4780 ssh_pkt_getstring(ssh, &banner, &size);
4781 if (banner)
4782 c_write_untrusted(ssh, banner, size);
4783 }
4784 crWaitUntilV(ispkt);
4785 }
4786 if (ssh->pktin.type == SSH2_MSG_USERAUTH_SUCCESS) {
4787 logevent("Access granted");
4788 s->we_are_in = TRUE;
4789 break;
4790 }
4791
4792 if (s->kbd_inter_running &&
4793 ssh->pktin.type == SSH2_MSG_USERAUTH_INFO_REQUEST) {
4794 /*
4795 * This is either a further set-of-prompts packet
4796 * in keyboard-interactive authentication, or it's
4797 * the same one and we came back here with `gotit'
4798 * set. In the former case, we must reset the
4799 * curr_prompt variable.
4800 */
4801 if (!s->gotit)
4802 s->curr_prompt = 0;
4803 } else if (ssh->pktin.type != SSH2_MSG_USERAUTH_FAILURE) {
4804 bombout(("Strange packet received during authentication: type %d",
4805 ssh->pktin.type));
4806 crStopV;
4807 }
4808
4809 s->gotit = FALSE;
4810
4811 /*
4812 * OK, we're now sitting on a USERAUTH_FAILURE message, so
4813 * we can look at the string in it and know what we can
4814 * helpfully try next.
4815 */
4816 if (ssh->pktin.type == SSH2_MSG_USERAUTH_FAILURE) {
4817 char *methods;
4818 int methlen;
4819 ssh_pkt_getstring(ssh, &methods, &methlen);
4820 s->kbd_inter_running = FALSE;
4821 if (!ssh2_pkt_getbool(ssh)) {
4822 /*
4823 * We have received an unequivocal Access
4824 * Denied. This can translate to a variety of
4825 * messages:
4826 *
4827 * - if we'd just tried "none" authentication,
4828 * it's not worth printing anything at all
4829 *
4830 * - if we'd just tried a public key _offer_,
4831 * the message should be "Server refused our
4832 * key" (or no message at all if the key
4833 * came from Pageant)
4834 *
4835 * - if we'd just tried anything else, the
4836 * message really should be "Access denied".
4837 *
4838 * Additionally, if we'd just tried password
4839 * authentication, we should break out of this
4840 * whole loop so as to go back to the username
4841 * prompt.
4842 */
4843 if (s->type == AUTH_TYPE_NONE) {
4844 /* do nothing */
4845 } else if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD ||
4846 s->type == AUTH_TYPE_PUBLICKEY_OFFER_QUIET) {
4847 if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD)
4848 c_write_str(ssh, "Server refused our key\r\n");
4849 logevent("Server refused public key");
4850 } else if (s->type==AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET) {
4851 /* server declined keyboard-interactive; ignore */
4852 } else {
4853 c_write_str(ssh, "Access denied\r\n");
4854 logevent("Access denied");
4855 if (s->type == AUTH_TYPE_PASSWORD) {
4856 s->we_are_in = FALSE;
4857 break;
4858 }
4859 }
4860 } else {
4861 c_write_str(ssh, "Further authentication required\r\n");
4862 logevent("Further authentication required");
4863 }
4864
4865 s->can_pubkey =
4866 in_commasep_string("publickey", methods, methlen);
4867 s->can_passwd =
4868 in_commasep_string("password", methods, methlen);
4869 s->can_keyb_inter = ssh->cfg.try_ki_auth &&
4870 in_commasep_string("keyboard-interactive", methods, methlen);
4871 }
4872
4873 s->method = 0;
4874 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4875 s->need_pw = FALSE;
4876
4877 /*
4878 * Most password/passphrase prompts will be
4879 * non-echoing, so we set this to 0 by default.
4880 * Exception is that some keyboard-interactive prompts
4881 * can be echoing, in which case we'll set this to 1.
4882 */
4883 s->echo = 0;
4884
4885 if (!s->method && s->can_pubkey &&
4886 agent_exists() && !s->tried_agent) {
4887 /*
4888 * Attempt public-key authentication using Pageant.
4889 */
4890 void *r;
4891 s->authed = FALSE;
4892
4893 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4894 ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
4895
4896 s->tried_agent = TRUE;
4897
4898 logevent("Pageant is running. Requesting keys.");
4899
4900 /* Request the keys held by the agent. */
4901 PUT_32BIT(s->request, 1);
4902 s->request[4] = SSH2_AGENTC_REQUEST_IDENTITIES;
4903 if (!agent_query(s->request, 5, &r, &s->responselen,
4904 ssh_agent_callback, ssh)) {
4905 do {
4906 crReturnV;
4907 if (ispkt) {
4908 bombout(("Unexpected data from server while"
4909 " waiting for agent response"));
4910 crStopV;
4911 }
4912 } while (ispkt || inlen > 0);
4913 r = ssh->agent_response;
4914 s->responselen = ssh->agent_response_len;
4915 }
4916 s->response = (unsigned char *) r;
4917 if (s->response && s->responselen >= 5 &&
4918 s->response[4] == SSH2_AGENT_IDENTITIES_ANSWER) {
4919 s->p = s->response + 5;
4920 s->nkeys = GET_32BIT(s->p);
4921 s->p += 4;
4922 {
4923 char buf[64];
4924 sprintf(buf, "Pageant has %d SSH2 keys", s->nkeys);
4925 logevent(buf);
4926 }
4927 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
4928 void *vret;
4929
4930 {
4931 char buf[64];
4932 sprintf(buf, "Trying Pageant key #%d", s->keyi);
4933 logevent(buf);
4934 }
4935 s->pklen = GET_32BIT(s->p);
4936 s->p += 4;
4937 if (s->publickey_blob &&
4938 s->pklen == s->publickey_bloblen &&
4939 !memcmp(s->p, s->publickey_blob,
4940 s->publickey_bloblen)) {
4941 logevent("This key matches configured key file");
4942 s->tried_pubkey_config = 1;
4943 }
4944 s->pkblob = (char *)s->p;
4945 s->p += s->pklen;
4946 s->alglen = GET_32BIT(s->pkblob);
4947 s->alg = s->pkblob + 4;
4948 s->commentlen = GET_32BIT(s->p);
4949 s->p += 4;
4950 s->commentp = (char *)s->p;
4951 s->p += s->commentlen;
4952 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4953 ssh2_pkt_addstring(ssh, s->username);
4954 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4955 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4956 ssh2_pkt_addbool(ssh, FALSE); /* no signature included */
4957 ssh2_pkt_addstring_start(ssh);
4958 ssh2_pkt_addstring_data(ssh, s->alg, s->alglen);
4959 ssh2_pkt_addstring_start(ssh);
4960 ssh2_pkt_addstring_data(ssh, s->pkblob, s->pklen);
4961 ssh2_pkt_send(ssh);
4962
4963 crWaitUntilV(ispkt);
4964 if (ssh->pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
4965 logevent("Key refused");
4966 continue;
4967 }
4968
4969 if (flags & FLAG_VERBOSE) {
4970 c_write_str(ssh, "Authenticating with "
4971 "public key \"");
4972 c_write(ssh, s->commentp, s->commentlen);
4973 c_write_str(ssh, "\" from agent\r\n");
4974 }
4975
4976 /*
4977 * Server is willing to accept the key.
4978 * Construct a SIGN_REQUEST.
4979 */
4980 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4981 ssh2_pkt_addstring(ssh, s->username);
4982 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4983 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4984 ssh2_pkt_addbool(ssh, TRUE);
4985 ssh2_pkt_addstring_start(ssh);
4986 ssh2_pkt_addstring_data(ssh, s->alg, s->alglen);
4987 ssh2_pkt_addstring_start(ssh);
4988 ssh2_pkt_addstring_data(ssh, s->pkblob, s->pklen);
4989
4990 s->siglen = ssh->pktout.length - 5 + 4 + 20;
4991 if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
4992 s->siglen -= 4;
4993 s->len = 1; /* message type */
4994 s->len += 4 + s->pklen; /* key blob */
4995 s->len += 4 + s->siglen; /* data to sign */
4996 s->len += 4; /* flags */
4997 s->agentreq = snewn(4 + s->len, char);
4998 PUT_32BIT(s->agentreq, s->len);
4999 s->q = s->agentreq + 4;
5000 *s->q++ = SSH2_AGENTC_SIGN_REQUEST;
5001 PUT_32BIT(s->q, s->pklen);
5002 s->q += 4;
5003 memcpy(s->q, s->pkblob, s->pklen);
5004 s->q += s->pklen;
5005 PUT_32BIT(s->q, s->siglen);
5006 s->q += 4;
5007 /* Now the data to be signed... */
5008 if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
5009 PUT_32BIT(s->q, 20);
5010 s->q += 4;
5011 }
5012 memcpy(s->q, ssh->v2_session_id, 20);
5013 s->q += 20;
5014 memcpy(s->q, ssh->pktout.data + 5,
5015 ssh->pktout.length - 5);
5016 s->q += ssh->pktout.length - 5;
5017 /* And finally the (zero) flags word. */
5018 PUT_32BIT(s->q, 0);
5019 if (!agent_query(s->agentreq, s->len + 4,
5020 &vret, &s->retlen,
5021 ssh_agent_callback, ssh)) {
5022 do {
5023 crReturnV;
5024 if (ispkt) {
5025 bombout(("Unexpected data from server"
5026 " while waiting for agent"
5027 " response"));
5028 crStopV;
5029 }
5030 } while (ispkt || inlen > 0);
5031 vret = ssh->agent_response;
5032 s->retlen = ssh->agent_response_len;
5033 }
5034 s->ret = vret;
5035 sfree(s->agentreq);
5036 if (s->ret) {
5037 if (s->ret[4] == SSH2_AGENT_SIGN_RESPONSE) {
5038 logevent("Sending Pageant's response");
5039 ssh2_add_sigblob(ssh, s->pkblob, s->pklen,
5040 s->ret + 9,
5041 GET_32BIT(s->ret + 5));
5042 ssh2_pkt_send(ssh);
5043 s->authed = TRUE;
5044 break;
5045 } else {
5046 logevent
5047 ("Pageant failed to answer challenge");
5048 sfree(s->ret);
5049 }
5050 }
5051 }
5052 if (s->authed)
5053 continue;
5054 }
5055 sfree(s->response);
5056 }
5057
5058 if (!s->method && s->can_pubkey && s->publickey_blob
5059 && !s->tried_pubkey_config) {
5060 unsigned char *pub_blob;
5061 char *algorithm, *comment;
5062 int pub_blob_len;
5063
5064 s->tried_pubkey_config = TRUE;
5065
5066 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
5067 ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
5068
5069 /*
5070 * Try the public key supplied in the configuration.
5071 *
5072 * First, offer the public blob to see if the server is
5073 * willing to accept it.
5074 */
5075 pub_blob =
5076 (unsigned char *)ssh2_userkey_loadpub(&ssh->cfg.keyfile,
5077 &algorithm,
5078 &pub_blob_len,
5079 NULL);
5080 if (pub_blob) {
5081 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
5082 ssh2_pkt_addstring(ssh, s->username);
5083 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
5084 ssh2_pkt_addstring(ssh, "publickey"); /* method */
5085 ssh2_pkt_addbool(ssh, FALSE); /* no signature included */
5086 ssh2_pkt_addstring(ssh, algorithm);
5087 ssh2_pkt_addstring_start(ssh);
5088 ssh2_pkt_addstring_data(ssh, (char *)pub_blob,
5089 pub_blob_len);
5090 ssh2_pkt_send(ssh);
5091 logevent("Offered public key"); /* FIXME */
5092
5093 crWaitUntilV(ispkt);
5094 if (ssh->pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
5095 s->gotit = TRUE;
5096 s->type = AUTH_TYPE_PUBLICKEY_OFFER_LOUD;
5097 continue; /* key refused; give up on it */
5098 }
5099
5100 logevent("Offer of public key accepted");
5101 /*
5102 * Actually attempt a serious authentication using
5103 * the key.
5104 */
5105 if (ssh2_userkey_encrypted(&ssh->cfg.keyfile, &comment)) {
5106 sprintf(s->pwprompt,
5107 "Passphrase for key \"%.100s\": ",
5108 comment);
5109 s->need_pw = TRUE;
5110 } else {
5111 s->need_pw = FALSE;
5112 }
5113 if (flags & FLAG_VERBOSE) {
5114 c_write_str(ssh, "Authenticating with public key \"");
5115 c_write_str(ssh, comment);
5116 c_write_str(ssh, "\"\r\n");
5117 }
5118 s->method = AUTH_PUBLICKEY_FILE;
5119 }
5120 }
5121
5122 if (!s->method && s->can_keyb_inter && !s->tried_keyb_inter) {
5123 s->method = AUTH_KEYBOARD_INTERACTIVE;
5124 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
5125 s->tried_keyb_inter = TRUE;
5126
5127 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
5128 ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;
5129
5130 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
5131 ssh2_pkt_addstring(ssh, s->username);
5132 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
5133 ssh2_pkt_addstring(ssh, "keyboard-interactive"); /* method */
5134 ssh2_pkt_addstring(ssh, ""); /* lang */
5135 ssh2_pkt_addstring(ssh, "");
5136 ssh2_pkt_send(ssh);
5137
5138 crWaitUntilV(ispkt);
5139 if (ssh->pktin.type != SSH2_MSG_USERAUTH_INFO_REQUEST) {
5140 if (ssh->pktin.type == SSH2_MSG_USERAUTH_FAILURE)
5141 s->gotit = TRUE;
5142 logevent("Keyboard-interactive authentication refused");
5143 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET;
5144 continue;
5145 }
5146
5147 s->kbd_inter_running = TRUE;
5148 s->curr_prompt = 0;
5149 }
5150
5151 if (s->kbd_inter_running) {
5152 s->method = AUTH_KEYBOARD_INTERACTIVE;
5153 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
5154 s->tried_keyb_inter = TRUE;
5155
5156 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
5157 ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;
5158
5159 if (s->curr_prompt == 0) {
5160 /*
5161 * We've got a fresh USERAUTH_INFO_REQUEST.
5162 * Display header data, and start going through
5163 * the prompts.
5164 */
5165 char *name, *inst, *lang;
5166 int name_len, inst_len, lang_len;
5167
5168 ssh_pkt_getstring(ssh, &name, &name_len);
5169 ssh_pkt_getstring(ssh, &inst, &inst_len);
5170 ssh_pkt_getstring(ssh, &lang, &lang_len);
5171 if (name_len > 0) {
5172 c_write_untrusted(ssh, name, name_len);
5173 c_write_str(ssh, "\r\n");
5174 }
5175 if (inst_len > 0) {
5176 c_write_untrusted(ssh, inst, inst_len);
5177 c_write_str(ssh, "\r\n");
5178 }
5179 s->num_prompts = ssh_pkt_getuint32(ssh);
5180 }
5181
5182 /*
5183 * If there are prompts remaining in the packet,
5184 * display one and get a response.
5185 */
5186 if (s->curr_prompt < s->num_prompts) {
5187 char *prompt;
5188 int prompt_len;
5189
5190 ssh_pkt_getstring(ssh, &prompt, &prompt_len);
5191 if (prompt_len > 0) {
5192 strncpy(s->pwprompt, prompt, sizeof(s->pwprompt));
5193 s->pwprompt[prompt_len < sizeof(s->pwprompt) ?
5194 prompt_len : sizeof(s->pwprompt)-1] = '\0';
5195 } else {
5196 strcpy(s->pwprompt,
5197 "<server failed to send prompt>: ");
5198 }
5199 s->echo = ssh2_pkt_getbool(ssh);
5200 s->need_pw = TRUE;
5201 } else
5202 s->need_pw = FALSE;
5203 }
5204
5205 if (!s->method && s->can_passwd) {
5206 s->method = AUTH_PASSWORD;
5207 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
5208 ssh->pkt_ctx |= SSH2_PKTCTX_PASSWORD;
5209 sprintf(s->pwprompt, "%.90s@%.90s's password: ", s->username,
5210 ssh->savedhost);
5211 s->need_pw = TRUE;
5212 }
5213
5214 if (s->need_pw) {
5215 if (ssh_get_line) {
5216 if (!ssh_get_line(s->pwprompt, s->password,
5217 sizeof(s->password), TRUE)) {
5218 /*
5219 * get_line failed to get a password (for
5220 * example because one was supplied on the
5221 * command line which has already failed to
5222 * work). Terminate.
5223 */
5224 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5225 ssh2_pkt_adduint32(ssh,SSH2_DISCONNECT_BY_APPLICATION);
5226 ssh2_pkt_addstring(ssh, "No more passwords available"
5227 " to try");
5228 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5229 ssh2_pkt_send(ssh);
5230 logevent("Unable to authenticate");
5231 connection_fatal(ssh->frontend,
5232 "Unable to authenticate");
5233 ssh_closing((Plug)ssh, NULL, 0, 0);
5234 crStopV;
5235 }
5236 } else {
5237 int ret; /* need not be saved across crReturn */
5238 c_write_untrusted(ssh, s->pwprompt, strlen(s->pwprompt));
5239 ssh->send_ok = 1;
5240
5241 setup_userpass_input(ssh, s->password,
5242 sizeof(s->password), s->echo);
5243 do {
5244 crWaitUntilV(!ispkt);
5245 ret = process_userpass_input(ssh, in, inlen);
5246 } while (ret == 0);
5247 if (ret < 0)
5248 cleanup_exit(0);
5249 c_write_str(ssh, "\r\n");
5250 }
5251 }
5252
5253 if (s->method == AUTH_PUBLICKEY_FILE) {
5254 /*
5255 * We have our passphrase. Now try the actual authentication.
5256 */
5257 struct ssh2_userkey *key;
5258 const char *error = NULL;
5259
5260 key = ssh2_load_userkey(&ssh->cfg.keyfile, s->password,
5261 &error);
5262 if (key == SSH2_WRONG_PASSPHRASE || key == NULL) {
5263 if (key == SSH2_WRONG_PASSPHRASE) {
5264 c_write_str(ssh, "Wrong passphrase\r\n");
5265 s->tried_pubkey_config = FALSE;
5266 } else {
5267 c_write_str(ssh, "Unable to load private key (");
5268 c_write_str(ssh, error);
5269 c_write_str(ssh, ")\r\n");
5270 s->tried_pubkey_config = TRUE;
5271 }
5272 /* Send a spurious AUTH_NONE to return to the top. */
5273 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
5274 ssh2_pkt_addstring(ssh, s->username);
5275 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
5276 ssh2_pkt_addstring(ssh, "none"); /* method */
5277 ssh2_pkt_send(ssh);
5278 s->type = AUTH_TYPE_NONE;
5279 } else {
5280 unsigned char *pkblob, *sigblob, *sigdata;
5281 int pkblob_len, sigblob_len, sigdata_len;
5282 int p;
5283
5284 /*
5285 * We have loaded the private key and the server
5286 * has announced that it's willing to accept it.
5287 * Hallelujah. Generate a signature and send it.
5288 */
5289 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
5290 ssh2_pkt_addstring(ssh, s->username);
5291 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
5292 ssh2_pkt_addstring(ssh, "publickey"); /* method */
5293 ssh2_pkt_addbool(ssh, TRUE);
5294 ssh2_pkt_addstring(ssh, key->alg->name);
5295 pkblob = key->alg->public_blob(key->data, &pkblob_len);
5296 ssh2_pkt_addstring_start(ssh);
5297 ssh2_pkt_addstring_data(ssh, (char *)pkblob, pkblob_len);
5298
5299 /*
5300 * The data to be signed is:
5301 *
5302 * string session-id
5303 *
5304 * followed by everything so far placed in the
5305 * outgoing packet.
5306 */
5307 sigdata_len = ssh->pktout.length - 5 + 4 + 20;
5308 if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
5309 sigdata_len -= 4;
5310 sigdata = snewn(sigdata_len, unsigned char);
5311 p = 0;
5312 if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
5313 PUT_32BIT(sigdata+p, 20);
5314 p += 4;
5315 }
5316 memcpy(sigdata+p, ssh->v2_session_id, 20); p += 20;
5317 memcpy(sigdata+p, ssh->pktout.data + 5,
5318 ssh->pktout.length - 5);
5319 p += ssh->pktout.length - 5;
5320 assert(p == sigdata_len);
5321 sigblob = key->alg->sign(key->data, (char *)sigdata,
5322 sigdata_len, &sigblob_len);
5323 ssh2_add_sigblob(ssh, pkblob, pkblob_len,
5324 sigblob, sigblob_len);
5325 sfree(pkblob);
5326 sfree(sigblob);
5327 sfree(sigdata);
5328
5329 ssh2_pkt_send(ssh);
5330 s->type = AUTH_TYPE_PUBLICKEY;
5331 key->alg->freekey(key->data);
5332 }
5333 } else if (s->method == AUTH_PASSWORD) {
5334 /*
5335 * We send the password packet lumped tightly together with
5336 * an SSH_MSG_IGNORE packet. The IGNORE packet contains a
5337 * string long enough to make the total length of the two
5338 * packets constant. This should ensure that a passive
5339 * listener doing traffic analyis can't work out the length
5340 * of the password.
5341 *
5342 * For this to work, we need an assumption about the
5343 * maximum length of the password packet. I think 256 is
5344 * pretty conservative. Anyone using a password longer than
5345 * that probably doesn't have much to worry about from
5346 * people who find out how long their password is!
5347 */
5348 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
5349 ssh2_pkt_addstring(ssh, s->username);
5350 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
5351 ssh2_pkt_addstring(ssh, "password");
5352 ssh2_pkt_addbool(ssh, FALSE);
5353 ssh2_pkt_addstring(ssh, s->password);
5354 memset(s->password, 0, sizeof(s->password));
5355 ssh2_pkt_defer(ssh);
5356 /*
5357 * We'll include a string that's an exact multiple of the
5358 * cipher block size. If the cipher is NULL for some
5359 * reason, we don't do this trick at all because we gain
5360 * nothing by it.
5361 */
5362 if (ssh->cscipher) {
5363 int stringlen, i;
5364
5365 stringlen = (256 - ssh->deferred_len);
5366 stringlen += ssh->cscipher->blksize - 1;
5367 stringlen -= (stringlen % ssh->cscipher->blksize);
5368 if (ssh->cscomp) {
5369 /*
5370 * Temporarily disable actual compression,
5371 * so we can guarantee to get this string
5372 * exactly the length we want it. The
5373 * compression-disabling routine should
5374 * return an integer indicating how many
5375 * bytes we should adjust our string length
5376 * by.
5377 */
5378 stringlen -=
5379 ssh->cscomp->disable_compression(ssh->cs_comp_ctx);
5380 }
5381 ssh2_pkt_init(ssh, SSH2_MSG_IGNORE);
5382 ssh2_pkt_addstring_start(ssh);
5383 for (i = 0; i < stringlen; i++) {
5384 char c = (char) random_byte();
5385 ssh2_pkt_addstring_data(ssh, &c, 1);
5386 }
5387 ssh2_pkt_defer(ssh);
5388 }
5389 ssh_pkt_defersend(ssh);
5390 logevent("Sent password");
5391 s->type = AUTH_TYPE_PASSWORD;
5392 } else if (s->method == AUTH_KEYBOARD_INTERACTIVE) {
5393 if (s->curr_prompt == 0) {
5394 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_INFO_RESPONSE);
5395 ssh2_pkt_adduint32(ssh, s->num_prompts);
5396 }
5397 if (s->need_pw) { /* only add pw if we just got one! */
5398 ssh2_pkt_addstring(ssh, s->password);
5399 memset(s->password, 0, sizeof(s->password));
5400 s->curr_prompt++;
5401 }
5402 if (s->curr_prompt >= s->num_prompts) {
5403 ssh2_pkt_send(ssh);
5404 } else {
5405 /*
5406 * If there are prompts remaining, we set
5407 * `gotit' so that we won't attempt to get
5408 * another packet. Then we go back round the
5409 * loop and will end up retrieving another
5410 * prompt out of the existing packet. Funky or
5411 * what?
5412 */
5413 s->gotit = TRUE;
5414 }
5415 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
5416 } else {
5417 c_write_str(ssh, "No supported authentication methods"
5418 " left to try!\r\n");
5419 logevent("No supported authentications offered."
5420 " Disconnecting");
5421 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5422 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5423 ssh2_pkt_addstring(ssh, "No supported authentication"
5424 " methods available");
5425 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5426 ssh2_pkt_send(ssh);
5427 ssh_closing((Plug)ssh, NULL, 0, 0);
5428 crStopV;
5429 }
5430 }
5431 } while (!s->we_are_in);
5432
5433 /*
5434 * Now we're authenticated for the connection protocol. The
5435 * connection protocol will automatically have started at this
5436 * point; there's no need to send SERVICE_REQUEST.
5437 */
5438
5439 /*
5440 * So now create a channel with a session in it.
5441 */
5442 ssh->channels = newtree234(ssh_channelcmp);
5443 ssh->mainchan = snew(struct ssh_channel);
5444 ssh->mainchan->ssh = ssh;
5445 ssh->mainchan->localid = alloc_channel_id(ssh);
5446 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN);
5447 ssh2_pkt_addstring(ssh, "session");
5448 ssh2_pkt_adduint32(ssh, ssh->mainchan->localid);
5449 ssh->mainchan->v.v2.locwindow = OUR_V2_WINSIZE;
5450 ssh2_pkt_adduint32(ssh, ssh->mainchan->v.v2.locwindow);/* our window size */
5451 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
5452 ssh2_pkt_send(ssh);
5453 crWaitUntilV(ispkt);
5454 if (ssh->pktin.type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
5455 bombout(("Server refused to open a session"));
5456 crStopV;
5457 /* FIXME: error data comes back in FAILURE packet */
5458 }
5459 if (ssh_pkt_getuint32(ssh) != ssh->mainchan->localid) {
5460 bombout(("Server's channel confirmation cited wrong channel"));
5461 crStopV;
5462 }
5463 ssh->mainchan->remoteid = ssh_pkt_getuint32(ssh);
5464 ssh->mainchan->type = CHAN_MAINSESSION;
5465 ssh->mainchan->closes = 0;
5466 ssh->mainchan->v.v2.remwindow = ssh_pkt_getuint32(ssh);
5467 ssh->mainchan->v.v2.remmaxpkt = ssh_pkt_getuint32(ssh);
5468 bufchain_init(&ssh->mainchan->v.v2.outbuffer);
5469 add234(ssh->channels, ssh->mainchan);
5470 logevent("Opened channel for session");
5471
5472 /*
5473 * Potentially enable X11 forwarding.
5474 */
5475 if (ssh->cfg.x11_forward) {
5476 char proto[20], data[64];
5477 logevent("Requesting X11 forwarding");
5478 ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
5479 data, sizeof(data), ssh->cfg.x11_auth);
5480 x11_get_real_auth(ssh->x11auth, ssh->cfg.x11_display);
5481 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5482 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
5483 ssh2_pkt_addstring(ssh, "x11-req");
5484 ssh2_pkt_addbool(ssh, 1); /* want reply */
5485 ssh2_pkt_addbool(ssh, 0); /* many connections */
5486 ssh2_pkt_addstring(ssh, proto);
5487 ssh2_pkt_addstring(ssh, data);
5488 ssh2_pkt_adduint32(ssh, x11_get_screen_number(ssh->cfg.x11_display));
5489 ssh2_pkt_send(ssh);
5490
5491 do {
5492 crWaitUntilV(ispkt);
5493 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5494 unsigned i = ssh_pkt_getuint32(ssh);
5495 struct ssh_channel *c;
5496 c = find234(ssh->channels, &i, ssh_channelfind);
5497 if (!c)
5498 continue; /* nonexistent channel */
5499 c->v.v2.remwindow += ssh_pkt_getuint32(ssh);
5500 }
5501 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5502
5503 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5504 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5505 bombout(("Unexpected response to X11 forwarding request:"
5506 " packet type %d", ssh->pktin.type));
5507 crStopV;
5508 }
5509 logevent("X11 forwarding refused");
5510 } else {
5511 logevent("X11 forwarding enabled");
5512 ssh->X11_fwd_enabled = TRUE;
5513 }
5514 }
5515
5516 /*
5517 * Enable port forwardings.
5518 */
5519 {
5520 char type;
5521 int n;
5522 int sport,dport,sserv,dserv;
5523 char sports[256], dports[256], saddr[256], host[256];
5524
5525 ssh->rportfwds = newtree234(ssh_rportcmp_ssh2);
5526 /* Add port forwardings. */
5527 ssh->portfwd_strptr = ssh->cfg.portfwd;
5528 while (*ssh->portfwd_strptr) {
5529 type = *ssh->portfwd_strptr++;
5530 saddr[0] = '\0';
5531 n = 0;
5532 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != '\t') {
5533 if (*ssh->portfwd_strptr == ':') {
5534 /*
5535 * We've seen a colon in the middle of the
5536 * source port number. This means that
5537 * everything we've seen until now is the
5538 * source _address_, so we'll move it into
5539 * saddr and start sports from the beginning
5540 * again.
5541 */
5542 ssh->portfwd_strptr++;
5543 sports[n] = '\0';
5544 strcpy(saddr, sports);
5545 n = 0;
5546 }
5547 if (n < 255) sports[n++] = *ssh->portfwd_strptr++;
5548 }
5549 sports[n] = 0;
5550 if (type != 'D') {
5551 if (*ssh->portfwd_strptr == '\t')
5552 ssh->portfwd_strptr++;
5553 n = 0;
5554 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':') {
5555 if (n < 255) host[n++] = *ssh->portfwd_strptr++;
5556 }
5557 host[n] = 0;
5558 if (*ssh->portfwd_strptr == ':')
5559 ssh->portfwd_strptr++;
5560 n = 0;
5561 while (*ssh->portfwd_strptr) {
5562 if (n < 255) dports[n++] = *ssh->portfwd_strptr++;
5563 }
5564 dports[n] = 0;
5565 ssh->portfwd_strptr++;
5566 dport = atoi(dports);
5567 dserv = 0;
5568 if (dport == 0) {
5569 dserv = 1;
5570 dport = net_service_lookup(dports);
5571 if (!dport) {
5572 logeventf(ssh, "Service lookup failed for destination"
5573 " port \"%s\"", dports);
5574 }
5575 }
5576 } else {
5577 while (*ssh->portfwd_strptr) ssh->portfwd_strptr++;
5578 dport = dserv = -1;
5579 ssh->portfwd_strptr++; /* eat the NUL and move to next one */
5580 }
5581 sport = atoi(sports);
5582 sserv = 0;
5583 if (sport == 0) {
5584 sserv = 1;
5585 sport = net_service_lookup(sports);
5586 if (!sport) {
5587 logeventf(ssh, "Service lookup failed for source"
5588 " port \"%s\"", sports);
5589 }
5590 }
5591 if (sport && dport) {
5592 if (type == 'L') {
5593 pfd_addforward(host, dport, *saddr ? saddr : NULL,
5594 sport, ssh, &ssh->cfg);
5595 logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
5596 " forwarding to %s:%.*s%.*s%d%.*s",
5597 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
5598 (int)(*saddr?1:0), ":",
5599 (int)(sserv ? strlen(sports) : 0), sports,
5600 sserv, "(", sport, sserv, ")",
5601 host,
5602 (int)(dserv ? strlen(dports) : 0), dports,
5603 dserv, "(", dport, dserv, ")");
5604 } else if (type == 'D') {
5605 pfd_addforward(NULL, -1, *saddr ? saddr : NULL,
5606 sport, ssh, &ssh->cfg);
5607 logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
5608 " doing SOCKS dynamic forwarding",
5609 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
5610 (int)(*saddr?1:0), ":",
5611 (int)(sserv ? strlen(sports) : 0), sports,
5612 sserv, "(", sport, sserv, ")");
5613 } else {
5614 struct ssh_rportfwd *pf;
5615 pf = snew(struct ssh_rportfwd);
5616 strcpy(pf->dhost, host);
5617 pf->dport = dport;
5618 pf->sport = sport;
5619 if (add234(ssh->rportfwds, pf) != pf) {
5620 logeventf(ssh, "Duplicate remote port forwarding"
5621 " to %s:%d", host, dport);
5622 sfree(pf);
5623 } else {
5624 logeventf(ssh, "Requesting remote port "
5625 "%.*s%.*s%.*s%.*s%d%.*s"
5626 " forward to %s:%.*s%.*s%d%.*s",
5627 (int)(*saddr?strlen(saddr):0),
5628 *saddr?saddr:NULL,
5629 (int)(*saddr?1:0), ":",
5630 (int)(sserv ? strlen(sports) : 0), sports,
5631 sserv, "(", sport, sserv, ")",
5632 host,
5633 (int)(dserv ? strlen(dports) : 0), dports,
5634 dserv, "(", dport, dserv, ")");
5635 ssh2_pkt_init(ssh, SSH2_MSG_GLOBAL_REQUEST);
5636 ssh2_pkt_addstring(ssh, "tcpip-forward");
5637 ssh2_pkt_addbool(ssh, 1);/* want reply */
5638 if (*saddr)
5639 ssh2_pkt_addstring(ssh, saddr);
5640 if (ssh->cfg.rport_acceptall)
5641 ssh2_pkt_addstring(ssh, "0.0.0.0");
5642 else
5643 ssh2_pkt_addstring(ssh, "127.0.0.1");
5644 ssh2_pkt_adduint32(ssh, sport);
5645 ssh2_pkt_send(ssh);
5646
5647 do {
5648 crWaitUntilV(ispkt);
5649 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5650 unsigned i = ssh_pkt_getuint32(ssh);
5651 struct ssh_channel *c;
5652 c = find234(ssh->channels, &i, ssh_channelfind);
5653 if (!c)
5654 continue;/* nonexistent channel */
5655 c->v.v2.remwindow += ssh_pkt_getuint32(ssh);
5656 }
5657 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5658
5659 if (ssh->pktin.type != SSH2_MSG_REQUEST_SUCCESS) {
5660 if (ssh->pktin.type != SSH2_MSG_REQUEST_FAILURE) {
5661 bombout(("Unexpected response to port "
5662 "forwarding request: packet type %d",
5663 ssh->pktin.type));
5664 crStopV;
5665 }
5666 logevent("Server refused this port forwarding");
5667 } else {
5668 logevent("Remote port forwarding enabled");
5669 }
5670 }
5671 }
5672 }
5673 }
5674 }
5675
5676 /*
5677 * Potentially enable agent forwarding.
5678 */
5679 if (ssh->cfg.agentfwd && agent_exists()) {
5680 logevent("Requesting OpenSSH-style agent forwarding");
5681 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5682 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
5683 ssh2_pkt_addstring(ssh, "auth-agent-req@openssh.com");
5684 ssh2_pkt_addbool(ssh, 1); /* want reply */
5685 ssh2_pkt_send(ssh);
5686
5687 do {
5688 crWaitUntilV(ispkt);
5689 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5690 unsigned i = ssh_pkt_getuint32(ssh);
5691 struct ssh_channel *c;
5692 c = find234(ssh->channels, &i, ssh_channelfind);
5693 if (!c)
5694 continue; /* nonexistent channel */
5695 c->v.v2.remwindow += ssh_pkt_getuint32(ssh);
5696 }
5697 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5698
5699 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5700 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5701 bombout(("Unexpected response to agent forwarding request:"
5702 " packet type %d", ssh->pktin.type));
5703 crStopV;
5704 }
5705 logevent("Agent forwarding refused");
5706 } else {
5707 logevent("Agent forwarding enabled");
5708 ssh->agentfwd_enabled = TRUE;
5709 }
5710 }
5711
5712 /*
5713 * Now allocate a pty for the session.
5714 */
5715 if (!ssh->cfg.nopty) {
5716 /* Unpick the terminal-speed string. */
5717 /* XXX perhaps we should allow no speeds to be sent. */
5718 ssh->ospeed = 38400; ssh->ispeed = 38400; /* last-resort defaults */
5719 sscanf(ssh->cfg.termspeed, "%d,%d", &ssh->ospeed, &ssh->ispeed);
5720 /* Build the pty request. */
5721 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5722 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid); /* recipient channel */
5723 ssh2_pkt_addstring(ssh, "pty-req");
5724 ssh2_pkt_addbool(ssh, 1); /* want reply */
5725 ssh2_pkt_addstring(ssh, ssh->cfg.termtype);
5726 ssh2_pkt_adduint32(ssh, ssh->term_width);
5727 ssh2_pkt_adduint32(ssh, ssh->term_height);
5728 ssh2_pkt_adduint32(ssh, 0); /* pixel width */
5729 ssh2_pkt_adduint32(ssh, 0); /* pixel height */
5730 ssh2_pkt_addstring_start(ssh);
5731 ssh2_pkt_addbyte(ssh, 128); /* TTY_OP_ISPEED */
5732 ssh2_pkt_adduint32(ssh, ssh->ispeed);
5733 ssh2_pkt_addbyte(ssh, 129); /* TTY_OP_OSPEED */
5734 ssh2_pkt_adduint32(ssh, ssh->ospeed);
5735 ssh2_pkt_addstring_data(ssh, "\0", 1); /* TTY_OP_END */
5736 ssh2_pkt_send(ssh);
5737 ssh->state = SSH_STATE_INTERMED;
5738
5739 do {
5740 crWaitUntilV(ispkt);
5741 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5742 unsigned i = ssh_pkt_getuint32(ssh);
5743 struct ssh_channel *c;
5744 c = find234(ssh->channels, &i, ssh_channelfind);
5745 if (!c)
5746 continue; /* nonexistent channel */
5747 c->v.v2.remwindow += ssh_pkt_getuint32(ssh);
5748 }
5749 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5750
5751 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5752 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5753 bombout(("Unexpected response to pty request:"
5754 " packet type %d", ssh->pktin.type));
5755 crStopV;
5756 }
5757 c_write_str(ssh, "Server refused to allocate pty\r\n");
5758 ssh->editing = ssh->echoing = 1;
5759 } else {
5760 logeventf(ssh, "Allocated pty (ospeed %dbps, ispeed %dbps)",
5761 ssh->ospeed, ssh->ispeed);
5762 }
5763 } else {
5764 ssh->editing = ssh->echoing = 1;
5765 }
5766
5767 /*
5768 * Start a shell or a remote command. We may have to attempt
5769 * this twice if the config data has provided a second choice
5770 * of command.
5771 */
5772 while (1) {
5773 int subsys;
5774 char *cmd;
5775
5776 if (ssh->fallback_cmd) {
5777 subsys = ssh->cfg.ssh_subsys2;
5778 cmd = ssh->cfg.remote_cmd_ptr2;
5779 } else {
5780 subsys = ssh->cfg.ssh_subsys;
5781 cmd = ssh->cfg.remote_cmd_ptr;
5782 }
5783
5784 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5785 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid); /* recipient channel */
5786 if (subsys) {
5787 ssh2_pkt_addstring(ssh, "subsystem");
5788 ssh2_pkt_addbool(ssh, 1); /* want reply */
5789 ssh2_pkt_addstring(ssh, cmd);
5790 } else if (*cmd) {
5791 ssh2_pkt_addstring(ssh, "exec");
5792 ssh2_pkt_addbool(ssh, 1); /* want reply */
5793 ssh2_pkt_addstring(ssh, cmd);
5794 } else {
5795 ssh2_pkt_addstring(ssh, "shell");
5796 ssh2_pkt_addbool(ssh, 1); /* want reply */
5797 }
5798 ssh2_pkt_send(ssh);
5799 do {
5800 crWaitUntilV(ispkt);
5801 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5802 unsigned i = ssh_pkt_getuint32(ssh);
5803 struct ssh_channel *c;
5804 c = find234(ssh->channels, &i, ssh_channelfind);
5805 if (!c)
5806 continue; /* nonexistent channel */
5807 c->v.v2.remwindow += ssh_pkt_getuint32(ssh);
5808 }
5809 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5810 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5811 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5812 bombout(("Unexpected response to shell/command request:"
5813 " packet type %d", ssh->pktin.type));
5814 crStopV;
5815 }
5816 /*
5817 * We failed to start the command. If this is the
5818 * fallback command, we really are finished; if it's
5819 * not, and if the fallback command exists, try falling
5820 * back to it before complaining.
5821 */
5822 if (!ssh->fallback_cmd && ssh->cfg.remote_cmd_ptr2 != NULL) {
5823 logevent("Primary command failed; attempting fallback");
5824 ssh->fallback_cmd = TRUE;
5825 continue;
5826 }
5827 bombout(("Server refused to start a shell/command"));
5828 crStopV;
5829 } else {
5830 logevent("Started a shell/command");
5831 }
5832 break;
5833 }
5834
5835 ssh->state = SSH_STATE_SESSION;
5836 if (ssh->size_needed)
5837 ssh_size(ssh, ssh->term_width, ssh->term_height);
5838 if (ssh->eof_needed)
5839 ssh_special(ssh, TS_EOF);
5840
5841 /*
5842 * Transfer data!
5843 */
5844 if (ssh->ldisc)
5845 ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */
5846 ssh->send_ok = 1;
5847 while (1) {
5848 crReturnV;
5849 s->try_send = FALSE;
5850 if (ispkt) {
5851 if (ssh->pktin.type == SSH2_MSG_CHANNEL_DATA ||
5852 ssh->pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA) {
5853 char *data;
5854 int length;
5855 unsigned i = ssh_pkt_getuint32(ssh);
5856 struct ssh_channel *c;
5857 c = find234(ssh->channels, &i, ssh_channelfind);
5858 if (!c)
5859 continue; /* nonexistent channel */
5860 if (ssh->pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
5861 ssh_pkt_getuint32(ssh) != SSH2_EXTENDED_DATA_STDERR)
5862 continue; /* extended but not stderr */
5863 ssh_pkt_getstring(ssh, &data, &length);
5864 if (data) {
5865 int bufsize = 0;
5866 c->v.v2.locwindow -= length;
5867 switch (c->type) {
5868 case CHAN_MAINSESSION:
5869 bufsize =
5870 from_backend(ssh->frontend, ssh->pktin.type ==
5871 SSH2_MSG_CHANNEL_EXTENDED_DATA,
5872 data, length);
5873 break;
5874 case CHAN_X11:
5875 bufsize = x11_send(c->u.x11.s, data, length);
5876 break;
5877 case CHAN_SOCKDATA:
5878 bufsize = pfd_send(c->u.pfd.s, data, length);
5879 break;
5880 case CHAN_AGENT:
5881 while (length > 0) {
5882 if (c->u.a.lensofar < 4) {
5883 int l = min(4 - c->u.a.lensofar, length);
5884 memcpy(c->u.a.msglen + c->u.a.lensofar,
5885 data, l);
5886 data += l;
5887 length -= l;
5888 c->u.a.lensofar += l;
5889 }
5890 if (c->u.a.lensofar == 4) {
5891 c->u.a.totallen =
5892 4 + GET_32BIT(c->u.a.msglen);
5893 c->u.a.message = snewn(c->u.a.totallen,
5894 unsigned char);
5895 memcpy(c->u.a.message, c->u.a.msglen, 4);
5896 }
5897 if (c->u.a.lensofar >= 4 && length > 0) {
5898 int l =
5899 min(c->u.a.totallen - c->u.a.lensofar,
5900 length);
5901 memcpy(c->u.a.message + c->u.a.lensofar,
5902 data, l);
5903 data += l;
5904 length -= l;
5905 c->u.a.lensofar += l;
5906 }
5907 if (c->u.a.lensofar == c->u.a.totallen) {
5908 void *reply;
5909 int replylen;
5910 if (agent_query(c->u.a.message,
5911 c->u.a.totallen,
5912 &reply, &replylen,
5913 ssh_agentf_callback, c))
5914 ssh_agentf_callback(c, reply, replylen);
5915 sfree(c->u.a.message);
5916 c->u.a.lensofar = 0;
5917 }
5918 }
5919 bufsize = 0;
5920 break;
5921 }
5922 /*
5923 * If we are not buffering too much data,
5924 * enlarge the window again at the remote side.
5925 */
5926 if (bufsize < OUR_V2_WINSIZE)
5927 ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
5928 }
5929 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_EOF) {
5930 unsigned i = ssh_pkt_getuint32(ssh);
5931 struct ssh_channel *c;
5932
5933 c = find234(ssh->channels, &i, ssh_channelfind);
5934 if (!c)
5935 continue; /* nonexistent channel */
5936
5937 if (c->type == CHAN_X11) {
5938 /*
5939 * Remote EOF on an X11 channel means we should
5940 * wrap up and close the channel ourselves.
5941 */
5942 x11_close(c->u.x11.s);
5943 sshfwd_close(c);
5944 } else if (c->type == CHAN_AGENT) {
5945 sshfwd_close(c);
5946 } else if (c->type == CHAN_SOCKDATA) {
5947 pfd_close(c->u.pfd.s);
5948 sshfwd_close(c);
5949 }
5950 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_CLOSE) {
5951 unsigned i = ssh_pkt_getuint32(ssh);
5952 struct ssh_channel *c;
5953
5954 c = find234(ssh->channels, &i, ssh_channelfind);
5955 if (!c || ((int)c->remoteid) == -1) {
5956 bombout(("Received CHANNEL_CLOSE for %s channel %d\n",
5957 c ? "half-open" : "nonexistent", i));
5958 crStopV;
5959 }
5960 /* Do pre-close processing on the channel. */
5961 switch (c->type) {
5962 case CHAN_MAINSESSION:
5963 break; /* nothing to see here, move along */
5964 case CHAN_X11:
5965 if (c->u.x11.s != NULL)
5966 x11_close(c->u.x11.s);
5967 sshfwd_close(c);
5968 break;
5969 case CHAN_AGENT:
5970 sshfwd_close(c);
5971 break;
5972 case CHAN_SOCKDATA:
5973 if (c->u.pfd.s != NULL)
5974 pfd_close(c->u.pfd.s);
5975 sshfwd_close(c);
5976 break;
5977 }
5978 if (c->closes == 0) {
5979 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
5980 ssh2_pkt_adduint32(ssh, c->remoteid);
5981 ssh2_pkt_send(ssh);
5982 }
5983 del234(ssh->channels, c);
5984 bufchain_clear(&c->v.v2.outbuffer);
5985 sfree(c);
5986
5987 /*
5988 * See if that was the last channel left open.
5989 */
5990 if (count234(ssh->channels) == 0) {
5991 logevent("All channels closed. Disconnecting");
5992 #if 0
5993 /*
5994 * We used to send SSH_MSG_DISCONNECT here,
5995 * because I'd believed that _every_ conforming
5996 * SSH2 connection had to end with a disconnect
5997 * being sent by at least one side; apparently
5998 * I was wrong and it's perfectly OK to
5999 * unceremoniously slam the connection shut
6000 * when you're done, and indeed OpenSSH feels
6001 * this is more polite than sending a
6002 * DISCONNECT. So now we don't.
6003 */
6004 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
6005 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
6006 ssh2_pkt_addstring(ssh, "All open channels closed");
6007 ssh2_pkt_addstring(ssh, "en"); /* language tag */
6008 ssh2_pkt_send(ssh);
6009 #endif
6010 ssh_closing((Plug)ssh, NULL, 0, 0);
6011 crStopV;
6012 }
6013 continue; /* remote sends close; ignore (FIXME) */
6014 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
6015 unsigned i = ssh_pkt_getuint32(ssh);
6016 struct ssh_channel *c;
6017 c = find234(ssh->channels, &i, ssh_channelfind);
6018 if (!c || c->closes)
6019 continue; /* nonexistent or closing channel */
6020 c->v.v2.remwindow += ssh_pkt_getuint32(ssh);
6021 s->try_send = TRUE;
6022 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
6023 unsigned i = ssh_pkt_getuint32(ssh);
6024 struct ssh_channel *c;
6025 c = find234(ssh->channels, &i, ssh_channelfind);
6026 if (!c)
6027 continue; /* nonexistent channel */
6028 if (c->type != CHAN_SOCKDATA_DORMANT)
6029 continue; /* dunno why they're confirming this */
6030 c->remoteid = ssh_pkt_getuint32(ssh);
6031 c->type = CHAN_SOCKDATA;
6032 c->v.v2.remwindow = ssh_pkt_getuint32(ssh);
6033 c->v.v2.remmaxpkt = ssh_pkt_getuint32(ssh);
6034 if (c->u.pfd.s)
6035 pfd_confirm(c->u.pfd.s);
6036 if (c->closes) {
6037 /*
6038 * We have a pending close on this channel,
6039 * which we decided on before the server acked
6040 * the channel open. So now we know the
6041 * remoteid, we can close it again.
6042 */
6043 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
6044 ssh2_pkt_adduint32(ssh, c->remoteid);
6045 ssh2_pkt_send(ssh);
6046 }
6047 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN_FAILURE) {
6048 unsigned i = ssh_pkt_getuint32(ssh);
6049 struct ssh_channel *c;
6050 c = find234(ssh->channels, &i, ssh_channelfind);
6051 if (!c)
6052 continue; /* nonexistent channel */
6053 if (c->type != CHAN_SOCKDATA_DORMANT)
6054 continue; /* dunno why they're failing this */
6055
6056 logevent("Forwarded connection refused by server");
6057
6058 pfd_close(c->u.pfd.s);
6059
6060 del234(ssh->channels, c);
6061 sfree(c);
6062 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_REQUEST) {
6063 unsigned localid;
6064 char *type;
6065 int typelen, want_reply;
6066 struct ssh_channel *c;
6067
6068 localid = ssh_pkt_getuint32(ssh);
6069 ssh_pkt_getstring(ssh, &type, &typelen);
6070 want_reply = ssh2_pkt_getbool(ssh);
6071
6072 /*
6073 * First, check that the channel exists. Otherwise,
6074 * we can instantly disconnect with a rude message.
6075 */
6076 c = find234(ssh->channels, &localid, ssh_channelfind);
6077 if (!c) {
6078 char buf[80];
6079 sprintf(buf, "Received channel request for nonexistent"
6080 " channel %d", localid);
6081 logevent(buf);
6082 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
6083 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
6084 ssh2_pkt_addstring(ssh, buf);
6085 ssh2_pkt_addstring(ssh, "en"); /* language tag */
6086 ssh2_pkt_send(ssh);
6087 connection_fatal(ssh->frontend, "%s", buf);
6088 ssh_closing((Plug)ssh, NULL, 0, 0);
6089 crStopV;
6090 }
6091
6092 /*
6093 * Having got the channel number, we now look at
6094 * the request type string to see if it's something
6095 * we recognise.
6096 */
6097 if (typelen == 11 && !memcmp(type, "exit-status", 11) &&
6098 c == ssh->mainchan) {
6099 /* We recognise "exit-status" on the primary channel. */
6100 char buf[100];
6101 ssh->exitcode = ssh_pkt_getuint32(ssh);
6102 sprintf(buf, "Server sent command exit status %d",
6103 ssh->exitcode);
6104 logevent(buf);
6105 if (want_reply) {
6106 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_SUCCESS);
6107 ssh2_pkt_adduint32(ssh, c->remoteid);
6108 ssh2_pkt_send(ssh);
6109 }
6110 } else {
6111 /*
6112 * This is a channel request we don't know
6113 * about, so we now either ignore the request
6114 * or respond with CHANNEL_FAILURE, depending
6115 * on want_reply.
6116 */
6117 if (want_reply) {
6118 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_FAILURE);
6119 ssh2_pkt_adduint32(ssh, c->remoteid);
6120 ssh2_pkt_send(ssh);
6121 }
6122 }
6123 } else if (ssh->pktin.type == SSH2_MSG_GLOBAL_REQUEST) {
6124 char *type;
6125 int typelen, want_reply;
6126
6127 ssh_pkt_getstring(ssh, &type, &typelen);
6128 want_reply = ssh2_pkt_getbool(ssh);
6129
6130 /*
6131 * We currently don't support any global requests
6132 * at all, so we either ignore the request or
6133 * respond with REQUEST_FAILURE, depending on
6134 * want_reply.
6135 */
6136 if (want_reply) {
6137 ssh2_pkt_init(ssh, SSH2_MSG_REQUEST_FAILURE);
6138 ssh2_pkt_send(ssh);
6139 }
6140 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN) {
6141 char *type;
6142 int typelen;
6143 char *peeraddr;
6144 int peeraddrlen;
6145 int peerport;
6146 char *error = NULL;
6147 struct ssh_channel *c;
6148 unsigned remid, winsize, pktsize;
6149 ssh_pkt_getstring(ssh, &type, &typelen);
6150 c = snew(struct ssh_channel);
6151 c->ssh = ssh;
6152
6153 remid = ssh_pkt_getuint32(ssh);
6154 winsize = ssh_pkt_getuint32(ssh);
6155 pktsize = ssh_pkt_getuint32(ssh);
6156
6157 if (typelen == 3 && !memcmp(type, "x11", 3)) {
6158 char *addrstr;
6159
6160 ssh_pkt_getstring(ssh, &peeraddr, &peeraddrlen);
6161 addrstr = snewn(peeraddrlen+1, char);
6162 memcpy(addrstr, peeraddr, peeraddrlen);
6163 peeraddr[peeraddrlen] = '\0';
6164 peerport = ssh_pkt_getuint32(ssh);
6165
6166 if (!ssh->X11_fwd_enabled)
6167 error = "X11 forwarding is not enabled";
6168 else if (x11_init(&c->u.x11.s, ssh->cfg.x11_display, c,
6169 ssh->x11auth, addrstr, peerport,
6170 &ssh->cfg) != NULL) {
6171 error = "Unable to open an X11 connection";
6172 } else {
6173 c->type = CHAN_X11;
6174 }
6175
6176 sfree(addrstr);
6177 } else if (typelen == 15 &&
6178 !memcmp(type, "forwarded-tcpip", 15)) {
6179 struct ssh_rportfwd pf, *realpf;
6180 char *dummy;
6181 int dummylen;
6182 ssh_pkt_getstring(ssh, &dummy, &dummylen);/* skip address */
6183 pf.sport = ssh_pkt_getuint32(ssh);
6184 ssh_pkt_getstring(ssh, &peeraddr, &peeraddrlen);
6185 peerport = ssh_pkt_getuint32(ssh);
6186 realpf = find234(ssh->rportfwds, &pf, NULL);
6187 if (realpf == NULL) {
6188 error = "Remote port is not recognised";
6189 } else {
6190 const char *e = pfd_newconnect(&c->u.pfd.s,
6191 realpf->dhost,
6192 realpf->dport, c,
6193 &ssh->cfg);
6194 logeventf(ssh, "Received remote port open request"
6195 " for %s:%d", realpf->dhost, realpf->dport);
6196 if (e != NULL) {
6197 logeventf(ssh, "Port open failed: %s", e);
6198 error = "Port open failed";
6199 } else {
6200 logevent("Forwarded port opened successfully");
6201 c->type = CHAN_SOCKDATA;
6202 }
6203 }
6204 } else if (typelen == 22 &&
6205 !memcmp(type, "auth-agent@openssh.com", 3)) {
6206 if (!ssh->agentfwd_enabled)
6207 error = "Agent forwarding is not enabled";
6208 else {
6209 c->type = CHAN_AGENT; /* identify channel type */
6210 c->u.a.lensofar = 0;
6211 }
6212 } else {
6213 error = "Unsupported channel type requested";
6214 }
6215
6216 c->remoteid = remid;
6217 if (error) {
6218 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN_FAILURE);
6219 ssh2_pkt_adduint32(ssh, c->remoteid);
6220 ssh2_pkt_adduint32(ssh, SSH2_OPEN_CONNECT_FAILED);
6221 ssh2_pkt_addstring(ssh, error);
6222 ssh2_pkt_addstring(ssh, "en"); /* language tag */
6223 ssh2_pkt_send(ssh);
6224 sfree(c);
6225 } else {
6226 c->localid = alloc_channel_id(ssh);
6227 c->closes = 0;
6228 c->v.v2.locwindow = OUR_V2_WINSIZE;
6229 c->v.v2.remwindow = winsize;
6230 c->v.v2.remmaxpkt = pktsize;
6231 bufchain_init(&c->v.v2.outbuffer);
6232 add234(ssh->channels, c);
6233 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
6234 ssh2_pkt_adduint32(ssh, c->remoteid);
6235 ssh2_pkt_adduint32(ssh, c->localid);
6236 ssh2_pkt_adduint32(ssh, c->v.v2.locwindow);
6237 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
6238 ssh2_pkt_send(ssh);
6239 }
6240 } else {
6241 bombout(("Strange packet received: type %d", ssh->pktin.type));
6242 crStopV;
6243 }
6244 } else {
6245 /*
6246 * We have spare data. Add it to the channel buffer.
6247 */
6248 ssh2_add_channel_data(ssh->mainchan, (char *)in, inlen);
6249 s->try_send = TRUE;
6250 }
6251 if (s->try_send) {
6252 int i;
6253 struct ssh_channel *c;
6254 /*
6255 * Try to send data on all channels if we can.
6256 */
6257 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
6258 int bufsize;
6259 if (c->closes)
6260 continue; /* don't send on closing channels */
6261 bufsize = ssh2_try_send(c);
6262 if (bufsize == 0) {
6263 switch (c->type) {
6264 case CHAN_MAINSESSION:
6265 /* stdin need not receive an unthrottle
6266 * notification since it will be polled */
6267 break;
6268 case CHAN_X11:
6269 x11_unthrottle(c->u.x11.s);
6270 break;
6271 case CHAN_AGENT:
6272 /* agent sockets are request/response and need no
6273 * buffer management */
6274 break;
6275 case CHAN_SOCKDATA:
6276 pfd_unthrottle(c->u.pfd.s);
6277 break;
6278 }
6279 }
6280 }
6281 }
6282 }
6283
6284 crFinishV;
6285 }
6286
6287 /*
6288 * Handle the top-level SSH2 protocol.
6289 */
6290 static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
6291 {
6292 if (do_ssh2_transport(ssh, in, inlen, ispkt) == 0)
6293 return;
6294 do_ssh2_authconn(ssh, in, inlen, ispkt);
6295 }
6296
6297 /*
6298 * Called to set up the connection.
6299 *
6300 * Returns an error message, or NULL on success.
6301 */
6302 static const char *ssh_init(void *frontend_handle, void **backend_handle,
6303 Config *cfg,
6304 char *host, int port, char **realhost, int nodelay,
6305 int keepalive)
6306 {
6307 const char *p;
6308 Ssh ssh;
6309
6310 ssh = snew(struct ssh_tag);
6311 ssh->cfg = *cfg; /* STRUCTURE COPY */
6312 ssh->version = 0; /* when not ready yet */
6313 ssh->s = NULL;
6314 ssh->cipher = NULL;
6315 ssh->v1_cipher_ctx = NULL;
6316 ssh->crcda_ctx = NULL;
6317 ssh->cscipher = NULL;
6318 ssh->cs_cipher_ctx = NULL;
6319 ssh->sccipher = NULL;
6320 ssh->sc_cipher_ctx = NULL;
6321 ssh->csmac = NULL;
6322 ssh->cs_mac_ctx = NULL;
6323 ssh->scmac = NULL;
6324 ssh->sc_mac_ctx = NULL;
6325 ssh->cscomp = NULL;
6326 ssh->cs_comp_ctx = NULL;
6327 ssh->sccomp = NULL;
6328 ssh->sc_comp_ctx = NULL;
6329 ssh->kex = NULL;
6330 ssh->kex_ctx = NULL;
6331 ssh->hostkey = NULL;
6332 ssh->exitcode = -1;
6333 ssh->state = SSH_STATE_PREPACKET;
6334 ssh->size_needed = FALSE;
6335 ssh->eof_needed = FALSE;
6336 ssh->ldisc = NULL;
6337 ssh->logctx = NULL;
6338 {
6339 static const struct Packet empty = { 0, 0, NULL, NULL, 0 };
6340 ssh->pktin = ssh->pktout = empty;
6341 }
6342 ssh->deferred_send_data = NULL;
6343 ssh->deferred_len = 0;
6344 ssh->deferred_size = 0;
6345 ssh->fallback_cmd = 0;
6346 ssh->pkt_ctx = 0;
6347 ssh->x11auth = NULL;
6348 ssh->v1_compressing = FALSE;
6349 ssh->v2_outgoing_sequence = 0;
6350 ssh->ssh1_rdpkt_crstate = 0;
6351 ssh->ssh2_rdpkt_crstate = 0;
6352 ssh->do_ssh_init_crstate = 0;
6353 ssh->ssh_gotdata_crstate = 0;
6354 ssh->ssh1_protocol_crstate = 0;
6355 ssh->do_ssh1_login_crstate = 0;
6356 ssh->do_ssh2_transport_crstate = 0;
6357 ssh->do_ssh2_authconn_crstate = 0;
6358 ssh->do_ssh_init_state = NULL;
6359 ssh->do_ssh1_login_state = NULL;
6360 ssh->do_ssh2_transport_state = NULL;
6361 ssh->do_ssh2_authconn_state = NULL;
6362 ssh->mainchan = NULL;
6363 ssh->throttled_all = 0;
6364 ssh->v1_stdout_throttling = 0;
6365
6366 *backend_handle = ssh;
6367
6368 #ifdef MSCRYPTOAPI
6369 if (crypto_startup() == 0)
6370 return "Microsoft high encryption pack not installed!";
6371 #endif
6372
6373 ssh->frontend = frontend_handle;
6374 ssh->term_width = ssh->cfg.width;
6375 ssh->term_height = ssh->cfg.height;
6376
6377 ssh->channels = NULL;
6378 ssh->rportfwds = NULL;
6379
6380 ssh->send_ok = 0;
6381 ssh->editing = 0;
6382 ssh->echoing = 0;
6383 ssh->v1_throttle_count = 0;
6384 ssh->overall_bufsize = 0;
6385 ssh->fallback_cmd = 0;
6386
6387 ssh->protocol = NULL;
6388
6389 p = connect_to_host(ssh, host, port, realhost, nodelay, keepalive);
6390 if (p != NULL)
6391 return p;
6392
6393 return NULL;
6394 }
6395
6396 static void ssh_free(void *handle)
6397 {
6398 Ssh ssh = (Ssh) handle;
6399 struct ssh_channel *c;
6400 struct ssh_rportfwd *pf;
6401
6402 if (ssh->v1_cipher_ctx)
6403 ssh->cipher->free_context(ssh->v1_cipher_ctx);
6404 if (ssh->cs_cipher_ctx)
6405 ssh->cscipher->free_context(ssh->cs_cipher_ctx);
6406 if (ssh->sc_cipher_ctx)
6407 ssh->sccipher->free_context(ssh->sc_cipher_ctx);
6408 if (ssh->cs_mac_ctx)
6409 ssh->csmac->free_context(ssh->cs_mac_ctx);
6410 if (ssh->sc_mac_ctx)
6411 ssh->scmac->free_context(ssh->sc_mac_ctx);
6412 if (ssh->cs_comp_ctx) {
6413 if (ssh->cscomp)
6414 ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
6415 else
6416 zlib_compress_cleanup(ssh->cs_comp_ctx);
6417 }
6418 if (ssh->sc_comp_ctx) {
6419 if (ssh->sccomp)
6420 ssh->sccomp->decompress_cleanup(ssh->sc_comp_ctx);
6421 else
6422 zlib_decompress_cleanup(ssh->sc_comp_ctx);
6423 }
6424 if (ssh->kex_ctx)
6425 dh_cleanup(ssh->kex_ctx);
6426 sfree(ssh->savedhost);
6427
6428 if (ssh->channels) {
6429 while ((c = delpos234(ssh->channels, 0)) != NULL) {
6430 switch (c->type) {
6431 case CHAN_X11:
6432 if (c->u.x11.s != NULL)
6433 x11_close(c->u.x11.s);
6434 break;
6435 case CHAN_SOCKDATA:
6436 if (c->u.pfd.s != NULL)
6437 pfd_close(c->u.pfd.s);
6438 break;
6439 }
6440 sfree(c);
6441 }
6442 freetree234(ssh->channels);
6443 }
6444
6445 if (ssh->rportfwds) {
6446 while ((pf = delpos234(ssh->rportfwds, 0)) != NULL)
6447 sfree(pf);
6448 freetree234(ssh->rportfwds);
6449 }
6450 sfree(ssh->deferred_send_data);
6451 if (ssh->x11auth)
6452 x11_free_auth(ssh->x11auth);
6453 sfree(ssh->do_ssh_init_state);
6454 sfree(ssh->do_ssh1_login_state);
6455 sfree(ssh->do_ssh2_transport_state);
6456 sfree(ssh->do_ssh2_authconn_state);
6457 if (ssh->pktout.data) {
6458 sfree(ssh->pktout.data);
6459 ssh->pktout.data = NULL;
6460 }
6461 if (ssh->pktin.data) {
6462 sfree(ssh->pktin.data);
6463 ssh->pktin.data = NULL;
6464 }
6465 if (ssh->crcda_ctx) {
6466 crcda_free_context(ssh->crcda_ctx);
6467 ssh->crcda_ctx = NULL;
6468 }
6469 if (ssh->logctx) {
6470 log_free(ssh->logctx);
6471 ssh->logctx = NULL;
6472 }
6473 if (ssh->s)
6474 ssh_do_close(ssh);
6475 sfree(ssh);
6476 }
6477
6478 /*
6479 * Reconfigure the SSH backend.
6480 *
6481 * Currently, this function does nothing very useful. In future,
6482 * however, we could do some handy things with it. For example, we
6483 * could make the port forwarding configurer active in the Change
6484 * Settings box, and this routine could close down existing
6485 * forwardings and open up new ones in response to changes.
6486 */
6487 static void ssh_reconfig(void *handle, Config *cfg)
6488 {
6489 Ssh ssh = (Ssh) handle;
6490 ssh->cfg = *cfg; /* STRUCTURE COPY */
6491 }
6492
6493 /*
6494 * Called to send data down the Telnet connection.
6495 */
6496 static int ssh_send(void *handle, char *buf, int len)
6497 {
6498 Ssh ssh = (Ssh) handle;
6499
6500 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
6501 return 0;
6502
6503 ssh->protocol(ssh, (unsigned char *)buf, len, 0);
6504
6505 return ssh_sendbuffer(ssh);
6506 }
6507
6508 /*
6509 * Called to query the current amount of buffered stdin data.
6510 */
6511 static int ssh_sendbuffer(void *handle)
6512 {
6513 Ssh ssh = (Ssh) handle;
6514 int override_value;
6515
6516 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
6517 return 0;
6518
6519 /*
6520 * If the SSH socket itself has backed up, add the total backup
6521 * size on that to any individual buffer on the stdin channel.
6522 */
6523 override_value = 0;
6524 if (ssh->throttled_all)
6525 override_value = ssh->overall_bufsize;
6526
6527 if (ssh->version == 1) {
6528 return override_value;
6529 } else if (ssh->version == 2) {
6530 if (!ssh->mainchan || ssh->mainchan->closes > 0)
6531 return override_value;
6532 else
6533 return (override_value +
6534 bufchain_size(&ssh->mainchan->v.v2.outbuffer));
6535 }
6536
6537 return 0;
6538 }
6539
6540 /*
6541 * Called to set the size of the window from SSH's POV.
6542 */
6543 static void ssh_size(void *handle, int width, int height)
6544 {
6545 Ssh ssh = (Ssh) handle;
6546
6547 ssh->term_width = width;
6548 ssh->term_height = height;
6549
6550 switch (ssh->state) {
6551 case SSH_STATE_BEFORE_SIZE:
6552 case SSH_STATE_PREPACKET:
6553 case SSH_STATE_CLOSED:
6554 break; /* do nothing */
6555 case SSH_STATE_INTERMED:
6556 ssh->size_needed = TRUE; /* buffer for later */
6557 break;
6558 case SSH_STATE_SESSION:
6559 if (!ssh->cfg.nopty) {
6560 if (ssh->version == 1) {
6561 send_packet(ssh, SSH1_CMSG_WINDOW_SIZE,
6562 PKT_INT, ssh->term_height,
6563 PKT_INT, ssh->term_width,
6564 PKT_INT, 0, PKT_INT, 0, PKT_END);
6565 } else {
6566 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
6567 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
6568 ssh2_pkt_addstring(ssh, "window-change");
6569 ssh2_pkt_addbool(ssh, 0);
6570 ssh2_pkt_adduint32(ssh, ssh->term_width);
6571 ssh2_pkt_adduint32(ssh, ssh->term_height);
6572 ssh2_pkt_adduint32(ssh, 0);
6573 ssh2_pkt_adduint32(ssh, 0);
6574 ssh2_pkt_send(ssh);
6575 }
6576 }
6577 break;
6578 }
6579 }
6580
6581 /*
6582 * Return a list of the special codes that make sense in this
6583 * protocol.
6584 */
6585 static const struct telnet_special *ssh_get_specials(void *handle)
6586 {
6587 Ssh ssh = (Ssh) handle;
6588
6589 if (ssh->version == 1) {
6590 static const struct telnet_special ssh1_specials[] = {
6591 {"IGNORE message", TS_NOP},
6592 {NULL, 0}
6593 };
6594 return ssh1_specials;
6595 } else if (ssh->version == 2) {
6596 static const struct telnet_special ssh2_specials[] = {
6597 {"Break", TS_BRK},
6598 {"IGNORE message", TS_NOP},
6599 {NULL, 0}
6600 };
6601 return ssh2_specials;
6602 } else
6603 return NULL;
6604 }
6605
6606 /*
6607 * Send Telnet special codes. TS_EOF is useful for `plink', so you
6608 * can send an EOF and collect resulting output (e.g. `plink
6609 * hostname sort').
6610 */
6611 static void ssh_special(void *handle, Telnet_Special code)
6612 {
6613 Ssh ssh = (Ssh) handle;
6614
6615 if (code == TS_EOF) {
6616 if (ssh->state != SSH_STATE_SESSION) {
6617 /*
6618 * Buffer the EOF in case we are pre-SESSION, so we can
6619 * send it as soon as we reach SESSION.
6620 */
6621 if (code == TS_EOF)
6622 ssh->eof_needed = TRUE;
6623 return;
6624 }
6625 if (ssh->version == 1) {
6626 send_packet(ssh, SSH1_CMSG_EOF, PKT_END);
6627 } else {
6628 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_EOF);
6629 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
6630 ssh2_pkt_send(ssh);
6631 }
6632 logevent("Sent EOF message");
6633 } else if (code == TS_PING || code == TS_NOP) {
6634 if (ssh->state == SSH_STATE_CLOSED
6635 || ssh->state == SSH_STATE_PREPACKET) return;
6636 if (ssh->version == 1) {
6637 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE))
6638 send_packet(ssh, SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
6639 } else {
6640 ssh2_pkt_init(ssh, SSH2_MSG_IGNORE);
6641 ssh2_pkt_addstring_start(ssh);
6642 ssh2_pkt_send(ssh);
6643 }
6644 } else if (code == TS_BRK) {
6645 if (ssh->state == SSH_STATE_CLOSED
6646 || ssh->state == SSH_STATE_PREPACKET) return;
6647 if (ssh->version == 1) {
6648 logevent("Unable to send BREAK signal in SSH1");
6649 } else {
6650 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
6651 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
6652 ssh2_pkt_addstring(ssh, "break");
6653 ssh2_pkt_addbool(ssh, 0);
6654 ssh2_pkt_adduint32(ssh, 0); /* default break length */
6655 ssh2_pkt_send(ssh);
6656 }
6657 } else {
6658 /* do nothing */
6659 }
6660 }
6661
6662 void *new_sock_channel(void *handle, Socket s)
6663 {
6664 Ssh ssh = (Ssh) handle;
6665 struct ssh_channel *c;
6666 c = snew(struct ssh_channel);
6667 c->ssh = ssh;
6668
6669 if (c) {
6670 c->remoteid = -1; /* to be set when open confirmed */
6671 c->localid = alloc_channel_id(ssh);
6672 c->closes = 0;
6673 c->type = CHAN_SOCKDATA_DORMANT;/* identify channel type */
6674 c->u.pfd.s = s;
6675 bufchain_init(&c->v.v2.outbuffer);
6676 add234(ssh->channels, c);
6677 }
6678 return c;
6679 }
6680
6681 /*
6682 * This is called when stdout/stderr (the entity to which
6683 * from_backend sends data) manages to clear some backlog.
6684 */
6685 static void ssh_unthrottle(void *handle, int bufsize)
6686 {
6687 Ssh ssh = (Ssh) handle;
6688 if (ssh->version == 1) {
6689 if (ssh->v1_stdout_throttling && bufsize < SSH1_BUFFER_LIMIT) {
6690 ssh->v1_stdout_throttling = 0;
6691 ssh1_throttle(ssh, -1);
6692 }
6693 } else {
6694 if (ssh->mainchan && ssh->mainchan->closes == 0)
6695 ssh2_set_window(ssh->mainchan, OUR_V2_WINSIZE - bufsize);
6696 }
6697 }
6698
6699 void ssh_send_port_open(void *channel, char *hostname, int port, char *org)
6700 {
6701 struct ssh_channel *c = (struct ssh_channel *)channel;
6702 Ssh ssh = c->ssh;
6703
6704 logeventf(ssh, "Opening forwarded connection to %s:%d", hostname, port);
6705
6706 if (ssh->version == 1) {
6707 send_packet(ssh, SSH1_MSG_PORT_OPEN,
6708 PKT_INT, c->localid,
6709 PKT_STR, hostname,
6710 PKT_INT, port,
6711 //PKT_STR, <org:orgport>,
6712 PKT_END);
6713 } else {
6714 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN);
6715 ssh2_pkt_addstring(ssh, "direct-tcpip");
6716 ssh2_pkt_adduint32(ssh, c->localid);
6717 c->v.v2.locwindow = OUR_V2_WINSIZE;
6718 ssh2_pkt_adduint32(ssh, c->v.v2.locwindow);/* our window size */
6719 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
6720 ssh2_pkt_addstring(ssh, hostname);
6721 ssh2_pkt_adduint32(ssh, port);
6722 /*
6723 * We make up values for the originator data; partly it's
6724 * too much hassle to keep track, and partly I'm not
6725 * convinced the server should be told details like that
6726 * about my local network configuration.
6727 */
6728 ssh2_pkt_addstring(ssh, "client-side-connection");
6729 ssh2_pkt_adduint32(ssh, 0);
6730 ssh2_pkt_send(ssh);
6731 }
6732 }
6733
6734
6735 static Socket ssh_socket(void *handle)
6736 {
6737 Ssh ssh = (Ssh) handle;
6738 return ssh->s;
6739 }
6740
6741 static int ssh_sendok(void *handle)
6742 {
6743 Ssh ssh = (Ssh) handle;
6744 return ssh->send_ok;
6745 }
6746
6747 static int ssh_ldisc(void *handle, int option)
6748 {
6749 Ssh ssh = (Ssh) handle;
6750 if (option == LD_ECHO)
6751 return ssh->echoing;
6752 if (option == LD_EDIT)
6753 return ssh->editing;
6754 return FALSE;
6755 }
6756
6757 static void ssh_provide_ldisc(void *handle, void *ldisc)
6758 {
6759 Ssh ssh = (Ssh) handle;
6760 ssh->ldisc = ldisc;
6761 }
6762
6763 static void ssh_provide_logctx(void *handle, void *logctx)
6764 {
6765 Ssh ssh = (Ssh) handle;
6766 ssh->logctx = logctx;
6767 }
6768
6769 static int ssh_return_exitcode(void *handle)
6770 {
6771 Ssh ssh = (Ssh) handle;
6772 if (ssh->s != NULL)
6773 return -1;
6774 else
6775 return (ssh->exitcode >= 0 ? ssh->exitcode : 0);
6776 }
6777
6778 /*
6779 * Gross hack: pscp will try to start SFTP but fall back to scp1 if
6780 * that fails. This variable is the means by which scp.c can reach
6781 * into the SSH code and find out which one it got.
6782 */
6783 extern int ssh_fallback_cmd(void *handle)
6784 {
6785 Ssh ssh = (Ssh) handle;
6786 return ssh->fallback_cmd;
6787 }
6788
6789 Backend ssh_backend = {
6790 ssh_init,
6791 ssh_free,
6792 ssh_reconfig,
6793 ssh_send,
6794 ssh_sendbuffer,
6795 ssh_size,
6796 ssh_special,
6797 ssh_get_specials,
6798 ssh_socket,
6799 ssh_return_exitcode,
6800 ssh_sendok,
6801 ssh_ldisc,
6802 ssh_provide_ldisc,
6803 ssh_provide_logctx,
6804 ssh_unthrottle,
6805 22
6806 };
Local modifications for Simon Tatham's `PuTTY' SSH client and terminal emulator