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Joe Yates's memory leak patches.
[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 term_width, term_height;
577
578 tree234 *channels; /* indexed by local id */
579 struct ssh_channel *mainchan; /* primary session channel */
580 int exitcode;
581
582 tree234 *rportfwds;
583
584 enum {
585 SSH_STATE_PREPACKET,
586 SSH_STATE_BEFORE_SIZE,
587 SSH_STATE_INTERMED,
588 SSH_STATE_SESSION,
589 SSH_STATE_CLOSED
590 } state;
591
592 int size_needed, eof_needed;
593
594 struct Packet pktin;
595 struct Packet pktout;
596 unsigned char *deferred_send_data;
597 int deferred_len, deferred_size;
598
599 /*
600 * Gross hack: pscp will try to start SFTP but fall back to
601 * scp1 if that fails. This variable is the means by which
602 * scp.c can reach into the SSH code and find out which one it
603 * got.
604 */
605 int fallback_cmd;
606
607 /*
608 * Used for username and password input.
609 */
610 char *userpass_input_buffer;
611 int userpass_input_buflen;
612 int userpass_input_bufpos;
613 int userpass_input_echo;
614
615 char *portfwd_strptr;
616 int pkt_ctx;
617
618 void *x11auth;
619
620 int version;
621 int v1_throttle_count;
622 int overall_bufsize;
623 int throttled_all;
624 int v1_stdout_throttling;
625 int v2_outgoing_sequence;
626
627 int ssh1_rdpkt_crstate;
628 int ssh2_rdpkt_crstate;
629 int do_ssh_init_crstate;
630 int ssh_gotdata_crstate;
631 int ssh1_protocol_crstate;
632 int do_ssh1_login_crstate;
633 int do_ssh2_transport_crstate;
634 int do_ssh2_authconn_crstate;
635
636 void *do_ssh_init_state;
637 void *do_ssh1_login_state;
638 void *do_ssh2_transport_state;
639 void *do_ssh2_authconn_state;
640
641 struct rdpkt1_state_tag rdpkt1_state;
642 struct rdpkt2_state_tag rdpkt2_state;
643
644 void (*protocol) (Ssh ssh, unsigned char *in, int inlen, int ispkt);
645 int (*s_rdpkt) (Ssh ssh, unsigned char **data, int *datalen);
646
647 /*
648 * We maintain a full _copy_ of a Config structure here, not
649 * merely a pointer to it. That way, when we're passed a new
650 * one for reconfiguration, we can check the differences and
651 * potentially reconfigure port forwardings etc in mid-session.
652 */
653 Config cfg;
654
655 /*
656 * Used to transfer data back from async agent callbacks.
657 */
658 void *agent_response;
659 int agent_response_len;
660 };
661
662 #define logevent(s) logevent(ssh->frontend, s)
663
664 /* logevent, only printf-formatted. */
665 static void logeventf(Ssh ssh, const char *fmt, ...)
666 {
667 va_list ap;
668 char *buf;
669
670 va_start(ap, fmt);
671 buf = dupvprintf(fmt, ap);
672 va_end(ap);
673 logevent(buf);
674 sfree(buf);
675 }
676
677 #define bombout(msg) \
678 do { \
679 char *text = dupprintf msg; \
680 ssh_do_close(ssh); \
681 logevent(text); \
682 connection_fatal(ssh->frontend, "%s", text); \
683 sfree(text); \
684 } while (0)
685
686 static int ssh_channelcmp(void *av, void *bv)
687 {
688 struct ssh_channel *a = (struct ssh_channel *) av;
689 struct ssh_channel *b = (struct ssh_channel *) bv;
690 if (a->localid < b->localid)
691 return -1;
692 if (a->localid > b->localid)
693 return +1;
694 return 0;
695 }
696 static int ssh_channelfind(void *av, void *bv)
697 {
698 unsigned *a = (unsigned *) av;
699 struct ssh_channel *b = (struct ssh_channel *) bv;
700 if (*a < b->localid)
701 return -1;
702 if (*a > b->localid)
703 return +1;
704 return 0;
705 }
706
707 static int ssh_rportcmp_ssh1(void *av, void *bv)
708 {
709 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
710 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
711 int i;
712 if ( (i = strcmp(a->dhost, b->dhost)) != 0)
713 return i < 0 ? -1 : +1;
714 if (a->dport > b->dport)
715 return +1;
716 if (a->dport < b->dport)
717 return -1;
718 return 0;
719 }
720
721 static int ssh_rportcmp_ssh2(void *av, void *bv)
722 {
723 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
724 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
725
726 if (a->sport > b->sport)
727 return +1;
728 if (a->sport < b->sport)
729 return -1;
730 return 0;
731 }
732
733 static int alloc_channel_id(Ssh ssh)
734 {
735 const unsigned CHANNEL_NUMBER_OFFSET = 256;
736 unsigned low, high, mid;
737 int tsize;
738 struct ssh_channel *c;
739
740 /*
741 * First-fit allocation of channel numbers: always pick the
742 * lowest unused one. To do this, binary-search using the
743 * counted B-tree to find the largest channel ID which is in a
744 * contiguous sequence from the beginning. (Precisely
745 * everything in that sequence must have ID equal to its tree
746 * index plus CHANNEL_NUMBER_OFFSET.)
747 */
748 tsize = count234(ssh->channels);
749
750 low = -1;
751 high = tsize;
752 while (high - low > 1) {
753 mid = (high + low) / 2;
754 c = index234(ssh->channels, mid);
755 if (c->localid == mid + CHANNEL_NUMBER_OFFSET)
756 low = mid; /* this one is fine */
757 else
758 high = mid; /* this one is past it */
759 }
760 /*
761 * Now low points to either -1, or the tree index of the
762 * largest ID in the initial sequence.
763 */
764 {
765 unsigned i = low + 1 + CHANNEL_NUMBER_OFFSET;
766 assert(NULL == find234(ssh->channels, &i, ssh_channelfind));
767 }
768 return low + 1 + CHANNEL_NUMBER_OFFSET;
769 }
770
771 static void c_write(Ssh ssh, const char *buf, int len)
772 {
773 if ((flags & FLAG_STDERR)) {
774 int i;
775 for (i = 0; i < len; i++)
776 if (buf[i] != '\r')
777 fputc(buf[i], stderr);
778 return;
779 }
780 from_backend(ssh->frontend, 1, buf, len);
781 }
782
783 static void c_write_untrusted(Ssh ssh, const char *buf, int len)
784 {
785 int i;
786 for (i = 0; i < len; i++) {
787 if (buf[i] == '\n')
788 c_write(ssh, "\r\n", 2);
789 else if ((buf[i] & 0x60) || (buf[i] == '\r'))
790 c_write(ssh, buf + i, 1);
791 }
792 }
793
794 static void c_write_str(Ssh ssh, const char *buf)
795 {
796 c_write(ssh, buf, strlen(buf));
797 }
798
799 /*
800 * Collect incoming data in the incoming packet buffer.
801 * Decipher and verify the packet when it is completely read.
802 * Drop SSH1_MSG_DEBUG and SSH1_MSG_IGNORE packets.
803 * Update the *data and *datalen variables.
804 * Return the additional nr of bytes needed, or 0 when
805 * a complete packet is available.
806 */
807 static int ssh1_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
808 {
809 struct rdpkt1_state_tag *st = &ssh->rdpkt1_state;
810
811 crBegin(ssh->ssh1_rdpkt_crstate);
812
813 next_packet:
814
815 ssh->pktin.type = 0;
816 ssh->pktin.length = 0;
817
818 for (st->i = st->len = 0; st->i < 4; st->i++) {
819 while ((*datalen) == 0)
820 crReturn(4 - st->i);
821 st->len = (st->len << 8) + **data;
822 (*data)++, (*datalen)--;
823 }
824
825 st->pad = 8 - (st->len % 8);
826 st->biglen = st->len + st->pad;
827 ssh->pktin.length = st->len - 5;
828
829 if (ssh->pktin.maxlen < st->biglen) {
830 ssh->pktin.maxlen = st->biglen;
831 ssh->pktin.data = sresize(ssh->pktin.data, st->biglen + APIEXTRA,
832 unsigned char);
833 }
834
835 st->to_read = st->biglen;
836 st->p = ssh->pktin.data;
837 while (st->to_read > 0) {
838 st->chunk = st->to_read;
839 while ((*datalen) == 0)
840 crReturn(st->to_read);
841 if (st->chunk > (*datalen))
842 st->chunk = (*datalen);
843 memcpy(st->p, *data, st->chunk);
844 *data += st->chunk;
845 *datalen -= st->chunk;
846 st->p += st->chunk;
847 st->to_read -= st->chunk;
848 }
849
850 if (ssh->cipher && detect_attack(ssh->crcda_ctx, ssh->pktin.data,
851 st->biglen, NULL)) {
852 bombout(("Network attack (CRC compensation) detected!"));
853 crStop(0);
854 }
855
856 if (ssh->cipher)
857 ssh->cipher->decrypt(ssh->v1_cipher_ctx, ssh->pktin.data, st->biglen);
858
859 st->realcrc = crc32_compute(ssh->pktin.data, st->biglen - 4);
860 st->gotcrc = GET_32BIT(ssh->pktin.data + st->biglen - 4);
861 if (st->gotcrc != st->realcrc) {
862 bombout(("Incorrect CRC received on packet"));
863 crStop(0);
864 }
865
866 ssh->pktin.body = ssh->pktin.data + st->pad + 1;
867
868 if (ssh->v1_compressing) {
869 unsigned char *decompblk;
870 int decomplen;
871 if (!zlib_decompress_block(ssh->sc_comp_ctx,
872 ssh->pktin.body - 1, ssh->pktin.length + 1,
873 &decompblk, &decomplen)) {
874 bombout(("Zlib decompression encountered invalid data"));
875 crStop(0);
876 }
877
878 if (ssh->pktin.maxlen < st->pad + decomplen) {
879 ssh->pktin.maxlen = st->pad + decomplen;
880 ssh->pktin.data = sresize(ssh->pktin.data,
881 ssh->pktin.maxlen + APIEXTRA,
882 unsigned char);
883 ssh->pktin.body = ssh->pktin.data + st->pad + 1;
884 }
885
886 memcpy(ssh->pktin.body - 1, decompblk, decomplen);
887 sfree(decompblk);
888 ssh->pktin.length = decomplen - 1;
889 }
890
891 ssh->pktin.type = ssh->pktin.body[-1];
892
893 if (ssh->logctx)
894 log_packet(ssh->logctx,
895 PKT_INCOMING, ssh->pktin.type,
896 ssh1_pkt_type(ssh->pktin.type),
897 ssh->pktin.body, ssh->pktin.length);
898
899 if (ssh->pktin.type == SSH1_SMSG_STDOUT_DATA ||
900 ssh->pktin.type == SSH1_SMSG_STDERR_DATA ||
901 ssh->pktin.type == SSH1_MSG_DEBUG ||
902 ssh->pktin.type == SSH1_SMSG_AUTH_TIS_CHALLENGE ||
903 ssh->pktin.type == SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
904 long stringlen = GET_32BIT(ssh->pktin.body);
905 if (stringlen + 4 != ssh->pktin.length) {
906 bombout(("Received data packet with bogus string length"));
907 crStop(0);
908 }
909 }
910
911 if (ssh->pktin.type == SSH1_MSG_DEBUG) {
912 /* log debug message */
913 char buf[512];
914 int stringlen = GET_32BIT(ssh->pktin.body);
915 strcpy(buf, "Remote debug message: ");
916 if (stringlen > 480)
917 stringlen = 480;
918 memcpy(buf + 8, ssh->pktin.body + 4, stringlen);
919 buf[8 + stringlen] = '\0';
920 logevent(buf);
921 goto next_packet;
922 } else if (ssh->pktin.type == SSH1_MSG_IGNORE) {
923 /* do nothing */
924 goto next_packet;
925 }
926
927 if (ssh->pktin.type == SSH1_MSG_DISCONNECT) {
928 /* log reason code in disconnect message */
929 char buf[256];
930 unsigned msglen = GET_32BIT(ssh->pktin.body);
931 unsigned nowlen;
932 strcpy(buf, "Remote sent disconnect: ");
933 nowlen = strlen(buf);
934 if (msglen > sizeof(buf) - nowlen - 1)
935 msglen = sizeof(buf) - nowlen - 1;
936 memcpy(buf + nowlen, ssh->pktin.body + 4, msglen);
937 buf[nowlen + msglen] = '\0';
938 /* logevent(buf); (this is now done within the bombout macro) */
939 bombout(("Server sent disconnect message:\n\"%s\"", buf+nowlen));
940 crStop(0);
941 }
942
943 crFinish(0);
944 }
945
946 static int ssh2_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
947 {
948 struct rdpkt2_state_tag *st = &ssh->rdpkt2_state;
949
950 crBegin(ssh->ssh2_rdpkt_crstate);
951
952 next_packet:
953 ssh->pktin.type = 0;
954 ssh->pktin.length = 0;
955 if (ssh->sccipher)
956 st->cipherblk = ssh->sccipher->blksize;
957 else
958 st->cipherblk = 8;
959 if (st->cipherblk < 8)
960 st->cipherblk = 8;
961
962 if (ssh->pktin.maxlen < st->cipherblk) {
963 ssh->pktin.maxlen = st->cipherblk;
964 ssh->pktin.data = sresize(ssh->pktin.data, st->cipherblk + APIEXTRA,
965 unsigned char);
966 }
967
968 /*
969 * Acquire and decrypt the first block of the packet. This will
970 * contain the length and padding details.
971 */
972 for (st->i = st->len = 0; st->i < st->cipherblk; st->i++) {
973 while ((*datalen) == 0)
974 crReturn(st->cipherblk - st->i);
975 ssh->pktin.data[st->i] = *(*data)++;
976 (*datalen)--;
977 }
978
979 if (ssh->sccipher)
980 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
981 ssh->pktin.data, st->cipherblk);
982
983 /*
984 * Now get the length and padding figures.
985 */
986 st->len = GET_32BIT(ssh->pktin.data);
987 st->pad = ssh->pktin.data[4];
988
989 /*
990 * _Completely_ silly lengths should be stomped on before they
991 * do us any more damage.
992 */
993 if (st->len < 0 || st->pad < 0 || st->len + st->pad < 0) {
994 bombout(("Incoming packet was garbled on decryption"));
995 crStop(0);
996 }
997
998 /*
999 * This enables us to deduce the payload length.
1000 */
1001 st->payload = st->len - st->pad - 1;
1002
1003 ssh->pktin.length = st->payload + 5;
1004
1005 /*
1006 * So now we can work out the total packet length.
1007 */
1008 st->packetlen = st->len + 4;
1009 st->maclen = ssh->scmac ? ssh->scmac->len : 0;
1010
1011 /*
1012 * Adjust memory allocation if packet is too big.
1013 */
1014 if (ssh->pktin.maxlen < st->packetlen + st->maclen) {
1015 ssh->pktin.maxlen = st->packetlen + st->maclen;
1016 ssh->pktin.data = sresize(ssh->pktin.data,
1017 ssh->pktin.maxlen + APIEXTRA,
1018 unsigned char);
1019 }
1020
1021 /*
1022 * Read and decrypt the remainder of the packet.
1023 */
1024 for (st->i = st->cipherblk; st->i < st->packetlen + st->maclen;
1025 st->i++) {
1026 while ((*datalen) == 0)
1027 crReturn(st->packetlen + st->maclen - st->i);
1028 ssh->pktin.data[st->i] = *(*data)++;
1029 (*datalen)--;
1030 }
1031 /* Decrypt everything _except_ the MAC. */
1032 if (ssh->sccipher)
1033 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
1034 ssh->pktin.data + st->cipherblk,
1035 st->packetlen - st->cipherblk);
1036
1037 /*
1038 * Check the MAC.
1039 */
1040 if (ssh->scmac
1041 && !ssh->scmac->verify(ssh->sc_mac_ctx, ssh->pktin.data, st->len + 4,
1042 st->incoming_sequence)) {
1043 bombout(("Incorrect MAC received on packet"));
1044 crStop(0);
1045 }
1046 st->incoming_sequence++; /* whether or not we MACed */
1047
1048 /*
1049 * Decompress packet payload.
1050 */
1051 {
1052 unsigned char *newpayload;
1053 int newlen;
1054 if (ssh->sccomp &&
1055 ssh->sccomp->decompress(ssh->sc_comp_ctx,
1056 ssh->pktin.data + 5, ssh->pktin.length - 5,
1057 &newpayload, &newlen)) {
1058 if (ssh->pktin.maxlen < newlen + 5) {
1059 ssh->pktin.maxlen = newlen + 5;
1060 ssh->pktin.data = sresize(ssh->pktin.data,
1061 ssh->pktin.maxlen + APIEXTRA,
1062 unsigned char);
1063 }
1064 ssh->pktin.length = 5 + newlen;
1065 memcpy(ssh->pktin.data + 5, newpayload, newlen);
1066 sfree(newpayload);
1067 }
1068 }
1069
1070 ssh->pktin.savedpos = 6;
1071 ssh->pktin.type = ssh->pktin.data[5];
1072
1073 if (ssh->logctx)
1074 log_packet(ssh->logctx, PKT_INCOMING, ssh->pktin.type,
1075 ssh2_pkt_type(ssh->pkt_ctx, ssh->pktin.type),
1076 ssh->pktin.data+6, ssh->pktin.length-6);
1077
1078 switch (ssh->pktin.type) {
1079 /*
1080 * These packets we must handle instantly.
1081 */
1082 case SSH2_MSG_DISCONNECT:
1083 {
1084 /* log reason code in disconnect message */
1085 char *buf;
1086 int nowlen;
1087 int reason = GET_32BIT(ssh->pktin.data + 6);
1088 unsigned msglen = GET_32BIT(ssh->pktin.data + 10);
1089
1090 if (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) {
1091 buf = dupprintf("Received disconnect message (%s)",
1092 ssh2_disconnect_reasons[reason]);
1093 } else {
1094 buf = dupprintf("Received disconnect message (unknown"
1095 " type %d)", reason);
1096 }
1097 logevent(buf);
1098 sfree(buf);
1099 buf = dupprintf("Disconnection message text: %n%.*s",
1100 &nowlen, msglen, ssh->pktin.data + 14);
1101 logevent(buf);
1102 bombout(("Server sent disconnect message\ntype %d (%s):\n\"%s\"",
1103 reason,
1104 (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) ?
1105 ssh2_disconnect_reasons[reason] : "unknown",
1106 buf+nowlen));
1107 sfree(buf);
1108 crStop(0);
1109 }
1110 break;
1111 case SSH2_MSG_IGNORE:
1112 goto next_packet;
1113 case SSH2_MSG_DEBUG:
1114 {
1115 /* log the debug message */
1116 char buf[512];
1117 /* int display = ssh->pktin.body[6]; */
1118 int stringlen = GET_32BIT(ssh->pktin.data+7);
1119 int prefix;
1120 strcpy(buf, "Remote debug message: ");
1121 prefix = strlen(buf);
1122 if (stringlen > (int)(sizeof(buf)-prefix-1))
1123 stringlen = sizeof(buf)-prefix-1;
1124 memcpy(buf + prefix, ssh->pktin.data + 11, stringlen);
1125 buf[prefix + stringlen] = '\0';
1126 logevent(buf);
1127 }
1128 goto next_packet; /* FIXME: print the debug message */
1129
1130 /*
1131 * These packets we need do nothing about here.
1132 */
1133 case SSH2_MSG_UNIMPLEMENTED:
1134 case SSH2_MSG_SERVICE_REQUEST:
1135 case SSH2_MSG_SERVICE_ACCEPT:
1136 case SSH2_MSG_KEXINIT:
1137 case SSH2_MSG_NEWKEYS:
1138 case SSH2_MSG_KEXDH_INIT:
1139 case SSH2_MSG_KEXDH_REPLY:
1140 /* case SSH2_MSG_KEX_DH_GEX_REQUEST: duplicate case value */
1141 /* case SSH2_MSG_KEX_DH_GEX_GROUP: duplicate case value */
1142 case SSH2_MSG_KEX_DH_GEX_INIT:
1143 case SSH2_MSG_KEX_DH_GEX_REPLY:
1144 case SSH2_MSG_USERAUTH_REQUEST:
1145 case SSH2_MSG_USERAUTH_FAILURE:
1146 case SSH2_MSG_USERAUTH_SUCCESS:
1147 case SSH2_MSG_USERAUTH_BANNER:
1148 case SSH2_MSG_USERAUTH_PK_OK:
1149 /* case SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ: duplicate case value */
1150 /* case SSH2_MSG_USERAUTH_INFO_REQUEST: duplicate case value */
1151 case SSH2_MSG_USERAUTH_INFO_RESPONSE:
1152 case SSH2_MSG_GLOBAL_REQUEST:
1153 case SSH2_MSG_REQUEST_SUCCESS:
1154 case SSH2_MSG_REQUEST_FAILURE:
1155 case SSH2_MSG_CHANNEL_OPEN:
1156 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION:
1157 case SSH2_MSG_CHANNEL_OPEN_FAILURE:
1158 case SSH2_MSG_CHANNEL_WINDOW_ADJUST:
1159 case SSH2_MSG_CHANNEL_DATA:
1160 case SSH2_MSG_CHANNEL_EXTENDED_DATA:
1161 case SSH2_MSG_CHANNEL_EOF:
1162 case SSH2_MSG_CHANNEL_CLOSE:
1163 case SSH2_MSG_CHANNEL_REQUEST:
1164 case SSH2_MSG_CHANNEL_SUCCESS:
1165 case SSH2_MSG_CHANNEL_FAILURE:
1166 break;
1167
1168 /*
1169 * For anything else we send SSH2_MSG_UNIMPLEMENTED.
1170 */
1171 default:
1172 ssh2_pkt_init(ssh, SSH2_MSG_UNIMPLEMENTED);
1173 ssh2_pkt_adduint32(ssh, st->incoming_sequence - 1);
1174 ssh2_pkt_send(ssh);
1175 break;
1176 }
1177
1178 crFinish(0);
1179 }
1180
1181 static void ssh1_pktout_size(Ssh ssh, int len)
1182 {
1183 int pad, biglen;
1184
1185 len += 5; /* type and CRC */
1186 pad = 8 - (len % 8);
1187 biglen = len + pad;
1188
1189 ssh->pktout.length = len - 5;
1190 if (ssh->pktout.maxlen < biglen) {
1191 ssh->pktout.maxlen = biglen;
1192 #ifdef MSCRYPTOAPI
1193 /* Allocate enough buffer space for extra block
1194 * for MS CryptEncrypt() */
1195 ssh->pktout.data = sresize(ssh->pktout.data, biglen + 12,
1196 unsigned char);
1197 #else
1198 ssh->pktout.data = sresize(ssh->pktout.data, biglen + 4,
1199 unsigned char);
1200 #endif
1201 }
1202 ssh->pktout.body = ssh->pktout.data + 4 + pad + 1;
1203 }
1204
1205 static void s_wrpkt_start(Ssh ssh, int type, int len)
1206 {
1207 ssh1_pktout_size(ssh, len);
1208 ssh->pktout.type = type;
1209 }
1210
1211 static int s_wrpkt_prepare(Ssh ssh)
1212 {
1213 int pad, biglen, i;
1214 unsigned long crc;
1215 #ifdef __SC__
1216 /*
1217 * XXX various versions of SC (including 8.8.4) screw up the
1218 * register allocation in this function and use the same register
1219 * (D6) for len and as a temporary, with predictable results. The
1220 * following sledgehammer prevents this.
1221 */
1222 volatile
1223 #endif
1224 int len;
1225
1226 ssh->pktout.body[-1] = ssh->pktout.type;
1227
1228 if (ssh->logctx)
1229 log_packet(ssh->logctx, PKT_OUTGOING, ssh->pktout.type,
1230 ssh1_pkt_type(ssh->pktout.type),
1231 ssh->pktout.body, ssh->pktout.length);
1232
1233 if (ssh->v1_compressing) {
1234 unsigned char *compblk;
1235 int complen;
1236 zlib_compress_block(ssh->cs_comp_ctx,
1237 ssh->pktout.body - 1, ssh->pktout.length + 1,
1238 &compblk, &complen);
1239 ssh1_pktout_size(ssh, complen - 1);
1240 memcpy(ssh->pktout.body - 1, compblk, complen);
1241 sfree(compblk);
1242 }
1243
1244 len = ssh->pktout.length + 5; /* type and CRC */
1245 pad = 8 - (len % 8);
1246 biglen = len + pad;
1247
1248 for (i = 0; i < pad; i++)
1249 ssh->pktout.data[i + 4] = random_byte();
1250 crc = crc32_compute(ssh->pktout.data + 4, biglen - 4);
1251 PUT_32BIT(ssh->pktout.data + biglen, crc);
1252 PUT_32BIT(ssh->pktout.data, len);
1253
1254 if (ssh->cipher)
1255 ssh->cipher->encrypt(ssh->v1_cipher_ctx, ssh->pktout.data + 4, biglen);
1256
1257 return biglen + 4;
1258 }
1259
1260 static void s_wrpkt(Ssh ssh)
1261 {
1262 int len, backlog;
1263 len = s_wrpkt_prepare(ssh);
1264 backlog = sk_write(ssh->s, (char *)ssh->pktout.data, len);
1265 if (backlog > SSH_MAX_BACKLOG)
1266 ssh_throttle_all(ssh, 1, backlog);
1267 }
1268
1269 static void s_wrpkt_defer(Ssh ssh)
1270 {
1271 int len;
1272 len = s_wrpkt_prepare(ssh);
1273 if (ssh->deferred_len + len > ssh->deferred_size) {
1274 ssh->deferred_size = ssh->deferred_len + len + 128;
1275 ssh->deferred_send_data = sresize(ssh->deferred_send_data,
1276 ssh->deferred_size,
1277 unsigned char);
1278 }
1279 memcpy(ssh->deferred_send_data + ssh->deferred_len, ssh->pktout.data, len);
1280 ssh->deferred_len += len;
1281 }
1282
1283 /*
1284 * Construct a packet with the specified contents.
1285 */
1286 static void construct_packet(Ssh ssh, int pkttype, va_list ap1, va_list ap2)
1287 {
1288 unsigned char *p, *argp, argchar;
1289 unsigned long argint;
1290 int pktlen, argtype, arglen;
1291 Bignum bn;
1292
1293 pktlen = 0;
1294 while ((argtype = va_arg(ap1, int)) != PKT_END) {
1295 switch (argtype) {
1296 case PKT_INT:
1297 (void) va_arg(ap1, int);
1298 pktlen += 4;
1299 break;
1300 case PKT_CHAR:
1301 (void) va_arg(ap1, int);
1302 pktlen++;
1303 break;
1304 case PKT_DATA:
1305 (void) va_arg(ap1, unsigned char *);
1306 arglen = va_arg(ap1, int);
1307 pktlen += arglen;
1308 break;
1309 case PKT_STR:
1310 argp = va_arg(ap1, unsigned char *);
1311 arglen = strlen((char *)argp);
1312 pktlen += 4 + arglen;
1313 break;
1314 case PKT_BIGNUM:
1315 bn = va_arg(ap1, Bignum);
1316 pktlen += ssh1_bignum_length(bn);
1317 break;
1318 default:
1319 assert(0);
1320 }
1321 }
1322
1323 s_wrpkt_start(ssh, pkttype, pktlen);
1324 p = ssh->pktout.body;
1325
1326 while ((argtype = va_arg(ap2, int)) != PKT_END) {
1327 switch (argtype) {
1328 case PKT_INT:
1329 argint = va_arg(ap2, int);
1330 PUT_32BIT(p, argint);
1331 p += 4;
1332 break;
1333 case PKT_CHAR:
1334 argchar = (unsigned char) va_arg(ap2, int);
1335 *p = argchar;
1336 p++;
1337 break;
1338 case PKT_DATA:
1339 argp = va_arg(ap2, unsigned char *);
1340 arglen = va_arg(ap2, int);
1341 memcpy(p, argp, arglen);
1342 p += arglen;
1343 break;
1344 case PKT_STR:
1345 argp = va_arg(ap2, unsigned char *);
1346 arglen = strlen((char *)argp);
1347 PUT_32BIT(p, arglen);
1348 memcpy(p + 4, argp, arglen);
1349 p += 4 + arglen;
1350 break;
1351 case PKT_BIGNUM:
1352 bn = va_arg(ap2, Bignum);
1353 p += ssh1_write_bignum(p, bn);
1354 break;
1355 }
1356 }
1357 }
1358
1359 static void send_packet(Ssh ssh, int pkttype, ...)
1360 {
1361 va_list ap1, ap2;
1362 va_start(ap1, pkttype);
1363 va_start(ap2, pkttype);
1364 construct_packet(ssh, pkttype, ap1, ap2);
1365 s_wrpkt(ssh);
1366 }
1367
1368 static void defer_packet(Ssh ssh, int pkttype, ...)
1369 {
1370 va_list ap1, ap2;
1371 va_start(ap1, pkttype);
1372 va_start(ap2, pkttype);
1373 construct_packet(ssh, pkttype, ap1, ap2);
1374 s_wrpkt_defer(ssh);
1375 }
1376
1377 static int ssh_versioncmp(char *a, char *b)
1378 {
1379 char *ae, *be;
1380 unsigned long av, bv;
1381
1382 av = strtoul(a, &ae, 10);
1383 bv = strtoul(b, &be, 10);
1384 if (av != bv)
1385 return (av < bv ? -1 : +1);
1386 if (*ae == '.')
1387 ae++;
1388 if (*be == '.')
1389 be++;
1390 av = strtoul(ae, &ae, 10);
1391 bv = strtoul(be, &be, 10);
1392 if (av != bv)
1393 return (av < bv ? -1 : +1);
1394 return 0;
1395 }
1396
1397 /*
1398 * Utility routines for putting an SSH-protocol `string' and
1399 * `uint32' into a SHA state.
1400 */
1401 #include <stdio.h>
1402 static void sha_string(SHA_State * s, void *str, int len)
1403 {
1404 unsigned char lenblk[4];
1405 PUT_32BIT(lenblk, len);
1406 SHA_Bytes(s, lenblk, 4);
1407 SHA_Bytes(s, str, len);
1408 }
1409
1410 static void sha_uint32(SHA_State * s, unsigned i)
1411 {
1412 unsigned char intblk[4];
1413 PUT_32BIT(intblk, i);
1414 SHA_Bytes(s, intblk, 4);
1415 }
1416
1417 /*
1418 * SSH2 packet construction functions.
1419 */
1420 static void ssh2_pkt_ensure(Ssh ssh, int length)
1421 {
1422 if (ssh->pktout.maxlen < length) {
1423 ssh->pktout.maxlen = length + 256;
1424 ssh->pktout.data = sresize(ssh->pktout.data,
1425 ssh->pktout.maxlen + APIEXTRA,
1426 unsigned char);
1427 if (!ssh->pktout.data)
1428 fatalbox("Out of memory");
1429 }
1430 }
1431 static void ssh2_pkt_adddata(Ssh ssh, void *data, int len)
1432 {
1433 ssh->pktout.length += len;
1434 ssh2_pkt_ensure(ssh, ssh->pktout.length);
1435 memcpy(ssh->pktout.data + ssh->pktout.length - len, data, len);
1436 }
1437 static void ssh2_pkt_addbyte(Ssh ssh, unsigned char byte)
1438 {
1439 ssh2_pkt_adddata(ssh, &byte, 1);
1440 }
1441 static void ssh2_pkt_init(Ssh ssh, int pkt_type)
1442 {
1443 ssh->pktout.length = 5;
1444 ssh2_pkt_addbyte(ssh, (unsigned char) pkt_type);
1445 }
1446 static void ssh2_pkt_addbool(Ssh ssh, unsigned char value)
1447 {
1448 ssh2_pkt_adddata(ssh, &value, 1);
1449 }
1450 static void ssh2_pkt_adduint32(Ssh ssh, unsigned long value)
1451 {
1452 unsigned char x[4];
1453 PUT_32BIT(x, value);
1454 ssh2_pkt_adddata(ssh, x, 4);
1455 }
1456 static void ssh2_pkt_addstring_start(Ssh ssh)
1457 {
1458 ssh2_pkt_adduint32(ssh, 0);
1459 ssh->pktout.savedpos = ssh->pktout.length;
1460 }
1461 static void ssh2_pkt_addstring_str(Ssh ssh, char *data)
1462 {
1463 ssh2_pkt_adddata(ssh, data, strlen(data));
1464 PUT_32BIT(ssh->pktout.data + ssh->pktout.savedpos - 4,
1465 ssh->pktout.length - ssh->pktout.savedpos);
1466 }
1467 static void ssh2_pkt_addstring_data(Ssh ssh, char *data, int len)
1468 {
1469 ssh2_pkt_adddata(ssh, data, len);
1470 PUT_32BIT(ssh->pktout.data + ssh->pktout.savedpos - 4,
1471 ssh->pktout.length - ssh->pktout.savedpos);
1472 }
1473 static void ssh2_pkt_addstring(Ssh ssh, char *data)
1474 {
1475 ssh2_pkt_addstring_start(ssh);
1476 ssh2_pkt_addstring_str(ssh, data);
1477 }
1478 static unsigned char *ssh2_mpint_fmt(Bignum b, int *len)
1479 {
1480 unsigned char *p;
1481 int i, n = (bignum_bitcount(b) + 7) / 8;
1482 p = snewn(n + 1, unsigned char);
1483 if (!p)
1484 fatalbox("out of memory");
1485 p[0] = 0;
1486 for (i = 1; i <= n; i++)
1487 p[i] = bignum_byte(b, n - i);
1488 i = 0;
1489 while (i <= n && p[i] == 0 && (p[i + 1] & 0x80) == 0)
1490 i++;
1491 memmove(p, p + i, n + 1 - i);
1492 *len = n + 1 - i;
1493 return p;
1494 }
1495 static void ssh2_pkt_addmp(Ssh ssh, Bignum b)
1496 {
1497 unsigned char *p;
1498 int len;
1499 p = ssh2_mpint_fmt(b, &len);
1500 ssh2_pkt_addstring_start(ssh);
1501 ssh2_pkt_addstring_data(ssh, (char *)p, len);
1502 sfree(p);
1503 }
1504
1505 /*
1506 * Construct an SSH2 final-form packet: compress it, encrypt it,
1507 * put the MAC on it. Final packet, ready to be sent, is stored in
1508 * ssh->pktout.data. Total length is returned.
1509 */
1510 static int ssh2_pkt_construct(Ssh ssh)
1511 {
1512 int cipherblk, maclen, padding, i;
1513
1514 if (ssh->logctx)
1515 log_packet(ssh->logctx, PKT_OUTGOING, ssh->pktout.data[5],
1516 ssh2_pkt_type(ssh->pkt_ctx, ssh->pktout.data[5]),
1517 ssh->pktout.data + 6, ssh->pktout.length - 6);
1518
1519 /*
1520 * Compress packet payload.
1521 */
1522 {
1523 unsigned char *newpayload;
1524 int newlen;
1525 if (ssh->cscomp &&
1526 ssh->cscomp->compress(ssh->cs_comp_ctx, ssh->pktout.data + 5,
1527 ssh->pktout.length - 5,
1528 &newpayload, &newlen)) {
1529 ssh->pktout.length = 5;
1530 ssh2_pkt_adddata(ssh, newpayload, newlen);
1531 sfree(newpayload);
1532 }
1533 }
1534
1535 /*
1536 * Add padding. At least four bytes, and must also bring total
1537 * length (minus MAC) up to a multiple of the block size.
1538 */
1539 cipherblk = ssh->cscipher ? ssh->cscipher->blksize : 8; /* block size */
1540 cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */
1541 padding = 4;
1542 padding +=
1543 (cipherblk - (ssh->pktout.length + padding) % cipherblk) % cipherblk;
1544 maclen = ssh->csmac ? ssh->csmac->len : 0;
1545 ssh2_pkt_ensure(ssh, ssh->pktout.length + padding + maclen);
1546 ssh->pktout.data[4] = padding;
1547 for (i = 0; i < padding; i++)
1548 ssh->pktout.data[ssh->pktout.length + i] = random_byte();
1549 PUT_32BIT(ssh->pktout.data, ssh->pktout.length + padding - 4);
1550 if (ssh->csmac)
1551 ssh->csmac->generate(ssh->cs_mac_ctx, ssh->pktout.data,
1552 ssh->pktout.length + padding,
1553 ssh->v2_outgoing_sequence);
1554 ssh->v2_outgoing_sequence++; /* whether or not we MACed */
1555
1556 if (ssh->cscipher)
1557 ssh->cscipher->encrypt(ssh->cs_cipher_ctx,
1558 ssh->pktout.data, ssh->pktout.length + padding);
1559
1560 /* Ready-to-send packet starts at ssh->pktout.data. We return length. */
1561 return ssh->pktout.length + padding + maclen;
1562 }
1563
1564 /*
1565 * Construct and send an SSH2 packet immediately.
1566 */
1567 static void ssh2_pkt_send(Ssh ssh)
1568 {
1569 int len;
1570 int backlog;
1571 len = ssh2_pkt_construct(ssh);
1572 backlog = sk_write(ssh->s, (char *)ssh->pktout.data, len);
1573 if (backlog > SSH_MAX_BACKLOG)
1574 ssh_throttle_all(ssh, 1, backlog);
1575 }
1576
1577 /*
1578 * Construct an SSH2 packet and add it to a deferred data block.
1579 * Useful for sending multiple packets in a single sk_write() call,
1580 * to prevent a traffic-analysing listener from being able to work
1581 * out the length of any particular packet (such as the password
1582 * packet).
1583 *
1584 * Note that because SSH2 sequence-numbers its packets, this can
1585 * NOT be used as an m4-style `defer' allowing packets to be
1586 * constructed in one order and sent in another.
1587 */
1588 static void ssh2_pkt_defer(Ssh ssh)
1589 {
1590 int len = ssh2_pkt_construct(ssh);
1591 if (ssh->deferred_len + len > ssh->deferred_size) {
1592 ssh->deferred_size = ssh->deferred_len + len + 128;
1593 ssh->deferred_send_data = sresize(ssh->deferred_send_data,
1594 ssh->deferred_size,
1595 unsigned char);
1596 }
1597 memcpy(ssh->deferred_send_data + ssh->deferred_len, ssh->pktout.data, len);
1598 ssh->deferred_len += len;
1599 }
1600
1601 /*
1602 * Send the whole deferred data block constructed by
1603 * ssh2_pkt_defer() or SSH1's defer_packet().
1604 */
1605 static void ssh_pkt_defersend(Ssh ssh)
1606 {
1607 int backlog;
1608 backlog = sk_write(ssh->s, (char *)ssh->deferred_send_data,
1609 ssh->deferred_len);
1610 ssh->deferred_len = ssh->deferred_size = 0;
1611 sfree(ssh->deferred_send_data);
1612 ssh->deferred_send_data = NULL;
1613 if (backlog > SSH_MAX_BACKLOG)
1614 ssh_throttle_all(ssh, 1, backlog);
1615 }
1616
1617 #if 0
1618 void bndebug(char *string, Bignum b)
1619 {
1620 unsigned char *p;
1621 int i, len;
1622 p = ssh2_mpint_fmt(b, &len);
1623 debug(("%s", string));
1624 for (i = 0; i < len; i++)
1625 debug((" %02x", p[i]));
1626 debug(("\n"));
1627 sfree(p);
1628 }
1629 #endif
1630
1631 static void sha_mpint(SHA_State * s, Bignum b)
1632 {
1633 unsigned char *p;
1634 int len;
1635 p = ssh2_mpint_fmt(b, &len);
1636 sha_string(s, p, len);
1637 sfree(p);
1638 }
1639
1640 /*
1641 * SSH2 packet decode functions.
1642 */
1643 static unsigned long ssh2_pkt_getuint32(Ssh ssh)
1644 {
1645 unsigned long value;
1646 if (ssh->pktin.length - ssh->pktin.savedpos < 4)
1647 return 0; /* arrgh, no way to decline (FIXME?) */
1648 value = GET_32BIT(ssh->pktin.data + ssh->pktin.savedpos);
1649 ssh->pktin.savedpos += 4;
1650 return value;
1651 }
1652 static int ssh2_pkt_getbool(Ssh ssh)
1653 {
1654 unsigned long value;
1655 if (ssh->pktin.length - ssh->pktin.savedpos < 1)
1656 return 0; /* arrgh, no way to decline (FIXME?) */
1657 value = ssh->pktin.data[ssh->pktin.savedpos] != 0;
1658 ssh->pktin.savedpos++;
1659 return value;
1660 }
1661 static void ssh2_pkt_getstring(Ssh ssh, char **p, int *length)
1662 {
1663 int len;
1664 *p = NULL;
1665 *length = 0;
1666 if (ssh->pktin.length - ssh->pktin.savedpos < 4)
1667 return;
1668 len = GET_32BIT(ssh->pktin.data + ssh->pktin.savedpos);
1669 if (len < 0)
1670 return;
1671 *length = len;
1672 ssh->pktin.savedpos += 4;
1673 if (ssh->pktin.length - ssh->pktin.savedpos < *length)
1674 return;
1675 *p = (char *)(ssh->pktin.data + ssh->pktin.savedpos);
1676 ssh->pktin.savedpos += *length;
1677 }
1678 static Bignum ssh2_pkt_getmp(Ssh ssh)
1679 {
1680 char *p;
1681 int length;
1682 Bignum b;
1683
1684 ssh2_pkt_getstring(ssh, &p, &length);
1685 if (!p)
1686 return NULL;
1687 if (p[0] & 0x80) {
1688 bombout(("internal error: Can't handle negative mpints"));
1689 return NULL;
1690 }
1691 b = bignum_from_bytes((unsigned char *)p, length);
1692 return b;
1693 }
1694
1695 /*
1696 * Helper function to add an SSH2 signature blob to a packet.
1697 * Expects to be shown the public key blob as well as the signature
1698 * blob. Normally works just like ssh2_pkt_addstring, but will
1699 * fiddle with the signature packet if necessary for
1700 * BUG_SSH2_RSA_PADDING.
1701 */
1702 static void ssh2_add_sigblob(Ssh ssh, void *pkblob_v, int pkblob_len,
1703 void *sigblob_v, int sigblob_len)
1704 {
1705 unsigned char *pkblob = (unsigned char *)pkblob_v;
1706 unsigned char *sigblob = (unsigned char *)sigblob_v;
1707
1708 /* dmemdump(pkblob, pkblob_len); */
1709 /* dmemdump(sigblob, sigblob_len); */
1710
1711 /*
1712 * See if this is in fact an ssh-rsa signature and a buggy
1713 * server; otherwise we can just do this the easy way.
1714 */
1715 if ((ssh->remote_bugs & BUG_SSH2_RSA_PADDING) &&
1716 (GET_32BIT(pkblob) == 7 && !memcmp(pkblob+4, "ssh-rsa", 7))) {
1717 int pos, len, siglen;
1718
1719 /*
1720 * Find the byte length of the modulus.
1721 */
1722
1723 pos = 4+7; /* skip over "ssh-rsa" */
1724 pos += 4 + GET_32BIT(pkblob+pos); /* skip over exponent */
1725 len = GET_32BIT(pkblob+pos); /* find length of modulus */
1726 pos += 4; /* find modulus itself */
1727 while (len > 0 && pkblob[pos] == 0)
1728 len--, pos++;
1729 /* debug(("modulus length is %d\n", len)); */
1730
1731 /*
1732 * Now find the signature integer.
1733 */
1734 pos = 4+7; /* skip over "ssh-rsa" */
1735 siglen = GET_32BIT(sigblob+pos);
1736 /* debug(("signature length is %d\n", siglen)); */
1737
1738 if (len != siglen) {
1739 unsigned char newlen[4];
1740 ssh2_pkt_addstring_start(ssh);
1741 ssh2_pkt_addstring_data(ssh, (char *)sigblob, pos);
1742 /* dmemdump(sigblob, pos); */
1743 pos += 4; /* point to start of actual sig */
1744 PUT_32BIT(newlen, len);
1745 ssh2_pkt_addstring_data(ssh, (char *)newlen, 4);
1746 /* dmemdump(newlen, 4); */
1747 newlen[0] = 0;
1748 while (len-- > siglen) {
1749 ssh2_pkt_addstring_data(ssh, (char *)newlen, 1);
1750 /* dmemdump(newlen, 1); */
1751 }
1752 ssh2_pkt_addstring_data(ssh, (char *)(sigblob+pos), siglen);
1753 /* dmemdump(sigblob+pos, siglen); */
1754 return;
1755 }
1756
1757 /* Otherwise fall through and do it the easy way. */
1758 }
1759
1760 ssh2_pkt_addstring_start(ssh);
1761 ssh2_pkt_addstring_data(ssh, (char *)sigblob, sigblob_len);
1762 }
1763
1764 /*
1765 * Examine the remote side's version string and compare it against
1766 * a list of known buggy implementations.
1767 */
1768 static void ssh_detect_bugs(Ssh ssh, char *vstring)
1769 {
1770 char *imp; /* pointer to implementation part */
1771 imp = vstring;
1772 imp += strcspn(imp, "-");
1773 if (*imp) imp++;
1774 imp += strcspn(imp, "-");
1775 if (*imp) imp++;
1776
1777 ssh->remote_bugs = 0;
1778
1779 if (ssh->cfg.sshbug_ignore1 == FORCE_ON ||
1780 (ssh->cfg.sshbug_ignore1 == AUTO &&
1781 (!strcmp(imp, "1.2.18") || !strcmp(imp, "1.2.19") ||
1782 !strcmp(imp, "1.2.20") || !strcmp(imp, "1.2.21") ||
1783 !strcmp(imp, "1.2.22") || !strcmp(imp, "Cisco-1.25") ||
1784 !strcmp(imp, "OSU_1.4alpha3")))) {
1785 /*
1786 * These versions don't support SSH1_MSG_IGNORE, so we have
1787 * to use a different defence against password length
1788 * sniffing.
1789 */
1790 ssh->remote_bugs |= BUG_CHOKES_ON_SSH1_IGNORE;
1791 logevent("We believe remote version has SSH1 ignore bug");
1792 }
1793
1794 if (ssh->cfg.sshbug_plainpw1 == FORCE_ON ||
1795 (ssh->cfg.sshbug_plainpw1 == AUTO &&
1796 (!strcmp(imp, "Cisco-1.25") || !strcmp(imp, "OSU_1.4alpha3")))) {
1797 /*
1798 * These versions need a plain password sent; they can't
1799 * handle having a null and a random length of data after
1800 * the password.
1801 */
1802 ssh->remote_bugs |= BUG_NEEDS_SSH1_PLAIN_PASSWORD;
1803 logevent("We believe remote version needs a plain SSH1 password");
1804 }
1805
1806 if (ssh->cfg.sshbug_rsa1 == FORCE_ON ||
1807 (ssh->cfg.sshbug_rsa1 == AUTO &&
1808 (!strcmp(imp, "Cisco-1.25")))) {
1809 /*
1810 * These versions apparently have no clue whatever about
1811 * RSA authentication and will panic and die if they see
1812 * an AUTH_RSA message.
1813 */
1814 ssh->remote_bugs |= BUG_CHOKES_ON_RSA;
1815 logevent("We believe remote version can't handle RSA authentication");
1816 }
1817
1818 if (ssh->cfg.sshbug_hmac2 == FORCE_ON ||
1819 (ssh->cfg.sshbug_hmac2 == AUTO &&
1820 !wc_match("* VShell", imp) &&
1821 (wc_match("2.1.0*", imp) || wc_match("2.0.*", imp) ||
1822 wc_match("2.2.0*", imp) || wc_match("2.3.0*", imp) ||
1823 wc_match("2.1 *", imp)))) {
1824 /*
1825 * These versions have the HMAC bug.
1826 */
1827 ssh->remote_bugs |= BUG_SSH2_HMAC;
1828 logevent("We believe remote version has SSH2 HMAC bug");
1829 }
1830
1831 if (ssh->cfg.sshbug_derivekey2 == FORCE_ON ||
1832 (ssh->cfg.sshbug_derivekey2 == AUTO &&
1833 !wc_match("* VShell", imp) &&
1834 (wc_match("2.0.0*", imp) || wc_match("2.0.10*", imp) ))) {
1835 /*
1836 * These versions have the key-derivation bug (failing to
1837 * include the literal shared secret in the hashes that
1838 * generate the keys).
1839 */
1840 ssh->remote_bugs |= BUG_SSH2_DERIVEKEY;
1841 logevent("We believe remote version has SSH2 key-derivation bug");
1842 }
1843
1844 if (ssh->cfg.sshbug_rsapad2 == FORCE_ON ||
1845 (ssh->cfg.sshbug_rsapad2 == AUTO &&
1846 (wc_match("OpenSSH_2.[5-9]*", imp) ||
1847 wc_match("OpenSSH_3.[0-2]*", imp)))) {
1848 /*
1849 * These versions have the SSH2 RSA padding bug.
1850 */
1851 ssh->remote_bugs |= BUG_SSH2_RSA_PADDING;
1852 logevent("We believe remote version has SSH2 RSA padding bug");
1853 }
1854
1855 if (ssh->cfg.sshbug_pksessid2 == FORCE_ON ||
1856 (ssh->cfg.sshbug_pksessid2 == AUTO &&
1857 wc_match("OpenSSH_2.[0-2]*", imp))) {
1858 /*
1859 * These versions have the SSH2 session-ID bug in
1860 * public-key authentication.
1861 */
1862 ssh->remote_bugs |= BUG_SSH2_PK_SESSIONID;
1863 logevent("We believe remote version has SSH2 public-key-session-ID bug");
1864 }
1865
1866 if (ssh->cfg.sshbug_dhgex2 == FORCE_ON) {
1867 /*
1868 * User specified the SSH2 DH GEX bug.
1869 */
1870 ssh->remote_bugs |= BUG_SSH2_DH_GEX;
1871 logevent("We believe remote version has SSH2 DH group exchange bug");
1872 }
1873 }
1874
1875 static int do_ssh_init(Ssh ssh, unsigned char c)
1876 {
1877 struct do_ssh_init_state {
1878 int vslen;
1879 char version[10];
1880 char *vstring;
1881 int vstrsize;
1882 int i;
1883 int proto1, proto2;
1884 };
1885 crState(do_ssh_init_state);
1886
1887 crBegin(ssh->do_ssh_init_crstate);
1888
1889 /* Search for the string "SSH-" in the input. */
1890 s->i = 0;
1891 while (1) {
1892 static const int transS[] = { 1, 2, 2, 1 };
1893 static const int transH[] = { 0, 0, 3, 0 };
1894 static const int transminus[] = { 0, 0, 0, -1 };
1895 if (c == 'S')
1896 s->i = transS[s->i];
1897 else if (c == 'H')
1898 s->i = transH[s->i];
1899 else if (c == '-')
1900 s->i = transminus[s->i];
1901 else
1902 s->i = 0;
1903 if (s->i < 0)
1904 break;
1905 crReturn(1); /* get another character */
1906 }
1907
1908 s->vstrsize = 16;
1909 s->vstring = snewn(s->vstrsize, char);
1910 strcpy(s->vstring, "SSH-");
1911 s->vslen = 4;
1912 s->i = 0;
1913 while (1) {
1914 crReturn(1); /* get another char */
1915 if (s->vslen >= s->vstrsize - 1) {
1916 s->vstrsize += 16;
1917 s->vstring = sresize(s->vstring, s->vstrsize, char);
1918 }
1919 s->vstring[s->vslen++] = c;
1920 if (s->i >= 0) {
1921 if (c == '-') {
1922 s->version[s->i] = '\0';
1923 s->i = -1;
1924 } else if (s->i < sizeof(s->version) - 1)
1925 s->version[s->i++] = c;
1926 } else if (c == '\012')
1927 break;
1928 }
1929
1930 ssh->agentfwd_enabled = FALSE;
1931 ssh->rdpkt2_state.incoming_sequence = 0;
1932
1933 s->vstring[s->vslen] = 0;
1934 s->vstring[strcspn(s->vstring, "\r\n")] = '\0';/* remove EOL chars */
1935 {
1936 char *vlog;
1937 vlog = snewn(20 + s->vslen, char);
1938 sprintf(vlog, "Server version: %s", s->vstring);
1939 logevent(vlog);
1940 sfree(vlog);
1941 }
1942 ssh_detect_bugs(ssh, s->vstring);
1943
1944 /*
1945 * Decide which SSH protocol version to support.
1946 */
1947
1948 /* Anything strictly below "2.0" means protocol 1 is supported. */
1949 s->proto1 = ssh_versioncmp(s->version, "2.0") < 0;
1950 /* Anything greater or equal to "1.99" means protocol 2 is supported. */
1951 s->proto2 = ssh_versioncmp(s->version, "1.99") >= 0;
1952
1953 if (ssh->cfg.sshprot == 0 && !s->proto1) {
1954 bombout(("SSH protocol version 1 required by user but not provided by server"));
1955 crStop(0);
1956 }
1957 if (ssh->cfg.sshprot == 3 && !s->proto2) {
1958 bombout(("SSH protocol version 2 required by user but not provided by server"));
1959 crStop(0);
1960 }
1961
1962 if (s->proto2 && (ssh->cfg.sshprot >= 2 || !s->proto1)) {
1963 /*
1964 * Use v2 protocol.
1965 */
1966 char verstring[80], vlog[100];
1967 sprintf(verstring, "SSH-2.0-%s", sshver);
1968 SHA_Init(&ssh->exhashbase);
1969 /*
1970 * Hash our version string and their version string.
1971 */
1972 sha_string(&ssh->exhashbase, verstring, strlen(verstring));
1973 sha_string(&ssh->exhashbase, s->vstring, strcspn(s->vstring, "\r\n"));
1974 sprintf(vlog, "We claim version: %s", verstring);
1975 logevent(vlog);
1976 strcat(verstring, "\012");
1977 logevent("Using SSH protocol version 2");
1978 sk_write(ssh->s, verstring, strlen(verstring));
1979 ssh->protocol = ssh2_protocol;
1980 ssh->version = 2;
1981 ssh->s_rdpkt = ssh2_rdpkt;
1982 } else {
1983 /*
1984 * Use v1 protocol.
1985 */
1986 char verstring[80], vlog[100];
1987 sprintf(verstring, "SSH-%s-%s",
1988 (ssh_versioncmp(s->version, "1.5") <= 0 ? s->version : "1.5"),
1989 sshver);
1990 sprintf(vlog, "We claim version: %s", verstring);
1991 logevent(vlog);
1992 strcat(verstring, "\012");
1993
1994 logevent("Using SSH protocol version 1");
1995 sk_write(ssh->s, verstring, strlen(verstring));
1996 ssh->protocol = ssh1_protocol;
1997 ssh->version = 1;
1998 ssh->s_rdpkt = ssh1_rdpkt;
1999 }
2000 update_specials_menu(ssh->frontend);
2001 ssh->state = SSH_STATE_BEFORE_SIZE;
2002
2003 sfree(s->vstring);
2004
2005 crFinish(0);
2006 }
2007
2008 static void ssh_gotdata(Ssh ssh, unsigned char *data, int datalen)
2009 {
2010 crBegin(ssh->ssh_gotdata_crstate);
2011
2012 /*
2013 * To begin with, feed the characters one by one to the
2014 * protocol initialisation / selection function do_ssh_init().
2015 * When that returns 0, we're done with the initial greeting
2016 * exchange and can move on to packet discipline.
2017 */
2018 while (1) {
2019 int ret; /* need not be kept across crReturn */
2020 if (datalen == 0)
2021 crReturnV; /* more data please */
2022 ret = do_ssh_init(ssh, *data);
2023 data++;
2024 datalen--;
2025 if (ret == 0)
2026 break;
2027 }
2028
2029 /*
2030 * We emerge from that loop when the initial negotiation is
2031 * over and we have selected an s_rdpkt function. Now pass
2032 * everything to s_rdpkt, and then pass the resulting packets
2033 * to the proper protocol handler.
2034 */
2035 if (datalen == 0)
2036 crReturnV;
2037 while (1) {
2038 while (datalen > 0) {
2039 if (ssh->s_rdpkt(ssh, &data, &datalen) == 0) {
2040 if (ssh->state == SSH_STATE_CLOSED) {
2041 return;
2042 }
2043 ssh->protocol(ssh, NULL, 0, 1);
2044 if (ssh->state == SSH_STATE_CLOSED) {
2045 return;
2046 }
2047 }
2048 }
2049 crReturnV;
2050 }
2051 crFinishV;
2052 }
2053
2054 static void ssh_do_close(Ssh ssh)
2055 {
2056 int i;
2057 struct ssh_channel *c;
2058
2059 ssh->state = SSH_STATE_CLOSED;
2060 if (ssh->s) {
2061 sk_close(ssh->s);
2062 ssh->s = NULL;
2063 }
2064 /*
2065 * Now we must shut down any port and X forwardings going
2066 * through this connection.
2067 */
2068 if (ssh->channels) {
2069 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
2070 switch (c->type) {
2071 case CHAN_X11:
2072 x11_close(c->u.x11.s);
2073 break;
2074 case CHAN_SOCKDATA:
2075 pfd_close(c->u.pfd.s);
2076 break;
2077 }
2078 del234(ssh->channels, c);
2079 if (ssh->version == 2)
2080 bufchain_clear(&c->v.v2.outbuffer);
2081 sfree(c);
2082 }
2083 }
2084 }
2085
2086 static int ssh_closing(Plug plug, const char *error_msg, int error_code,
2087 int calling_back)
2088 {
2089 Ssh ssh = (Ssh) plug;
2090 ssh_do_close(ssh);
2091 if (error_msg) {
2092 /* A socket error has occurred. */
2093 logevent(error_msg);
2094 connection_fatal(ssh->frontend, "%s", error_msg);
2095 } else {
2096 /* Otherwise, the remote side closed the connection normally. */
2097 }
2098 return 0;
2099 }
2100
2101 static int ssh_receive(Plug plug, int urgent, char *data, int len)
2102 {
2103 Ssh ssh = (Ssh) plug;
2104 ssh_gotdata(ssh, (unsigned char *)data, len);
2105 if (ssh->state == SSH_STATE_CLOSED) {
2106 ssh_do_close(ssh);
2107 return 0;
2108 }
2109 return 1;
2110 }
2111
2112 static void ssh_sent(Plug plug, int bufsize)
2113 {
2114 Ssh ssh = (Ssh) plug;
2115 /*
2116 * If the send backlog on the SSH socket itself clears, we
2117 * should unthrottle the whole world if it was throttled.
2118 */
2119 if (bufsize < SSH_MAX_BACKLOG)
2120 ssh_throttle_all(ssh, 0, bufsize);
2121 }
2122
2123 /*
2124 * Connect to specified host and port.
2125 * Returns an error message, or NULL on success.
2126 * Also places the canonical host name into `realhost'. It must be
2127 * freed by the caller.
2128 */
2129 static const char *connect_to_host(Ssh ssh, char *host, int port,
2130 char **realhost, int nodelay)
2131 {
2132 static const struct plug_function_table fn_table = {
2133 ssh_closing,
2134 ssh_receive,
2135 ssh_sent,
2136 NULL
2137 };
2138
2139 SockAddr addr;
2140 const char *err;
2141
2142 ssh->savedhost = snewn(1 + strlen(host), char);
2143 if (!ssh->savedhost)
2144 fatalbox("Out of memory");
2145 strcpy(ssh->savedhost, host);
2146
2147 if (port < 0)
2148 port = 22; /* default ssh port */
2149 ssh->savedport = port;
2150
2151 /*
2152 * Try to find host.
2153 */
2154 logeventf(ssh, "Looking up host \"%s\"", host);
2155 addr = name_lookup(host, port, realhost, &ssh->cfg);
2156 if ((err = sk_addr_error(addr)) != NULL) {
2157 sk_addr_free(addr);
2158 return err;
2159 }
2160
2161 /*
2162 * Open socket.
2163 */
2164 {
2165 char addrbuf[100];
2166 sk_getaddr(addr, addrbuf, 100);
2167 logeventf(ssh, "Connecting to %s port %d", addrbuf, port);
2168 }
2169 ssh->fn = &fn_table;
2170 ssh->s = new_connection(addr, *realhost, port,
2171 0, 1, nodelay, (Plug) ssh, &ssh->cfg);
2172 if ((err = sk_socket_error(ssh->s)) != NULL) {
2173 ssh->s = NULL;
2174 return err;
2175 }
2176
2177 return NULL;
2178 }
2179
2180 /*
2181 * Throttle or unthrottle the SSH connection.
2182 */
2183 static void ssh1_throttle(Ssh ssh, int adjust)
2184 {
2185 int old_count = ssh->v1_throttle_count;
2186 ssh->v1_throttle_count += adjust;
2187 assert(ssh->v1_throttle_count >= 0);
2188 if (ssh->v1_throttle_count && !old_count) {
2189 sk_set_frozen(ssh->s, 1);
2190 } else if (!ssh->v1_throttle_count && old_count) {
2191 sk_set_frozen(ssh->s, 0);
2192 }
2193 }
2194
2195 /*
2196 * Throttle or unthrottle _all_ local data streams (for when sends
2197 * on the SSH connection itself back up).
2198 */
2199 static void ssh_throttle_all(Ssh ssh, int enable, int bufsize)
2200 {
2201 int i;
2202 struct ssh_channel *c;
2203
2204 if (enable == ssh->throttled_all)
2205 return;
2206 ssh->throttled_all = enable;
2207 ssh->overall_bufsize = bufsize;
2208 if (!ssh->channels)
2209 return;
2210 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
2211 switch (c->type) {
2212 case CHAN_MAINSESSION:
2213 /*
2214 * This is treated separately, outside the switch.
2215 */
2216 break;
2217 case CHAN_X11:
2218 x11_override_throttle(c->u.x11.s, enable);
2219 break;
2220 case CHAN_AGENT:
2221 /* Agent channels require no buffer management. */
2222 break;
2223 case CHAN_SOCKDATA:
2224 pfd_override_throttle(c->u.pfd.s, enable);
2225 break;
2226 }
2227 }
2228 }
2229
2230 /*
2231 * Username and password input, abstracted off into routines
2232 * reusable in several places - even between SSH1 and SSH2.
2233 */
2234
2235 /* Set up a username or password input loop on a given buffer. */
2236 static void setup_userpass_input(Ssh ssh, char *buffer, int buflen, int echo)
2237 {
2238 ssh->userpass_input_buffer = buffer;
2239 ssh->userpass_input_buflen = buflen;
2240 ssh->userpass_input_bufpos = 0;
2241 ssh->userpass_input_echo = echo;
2242 }
2243
2244 /*
2245 * Process some terminal data in the course of username/password
2246 * input. Returns >0 for success (line of input returned in
2247 * buffer), <0 for failure (user hit ^C/^D, bomb out and exit), 0
2248 * for inconclusive (keep waiting for more input please).
2249 */
2250 static int process_userpass_input(Ssh ssh, unsigned char *in, int inlen)
2251 {
2252 char c;
2253
2254 while (inlen--) {
2255 switch (c = *in++) {
2256 case 10:
2257 case 13:
2258 ssh->userpass_input_buffer[ssh->userpass_input_bufpos] = 0;
2259 ssh->userpass_input_buffer[ssh->userpass_input_buflen-1] = 0;
2260 return +1;
2261 break;
2262 case 8:
2263 case 127:
2264 if (ssh->userpass_input_bufpos > 0) {
2265 if (ssh->userpass_input_echo)
2266 c_write_str(ssh, "\b \b");
2267 ssh->userpass_input_bufpos--;
2268 }
2269 break;
2270 case 21:
2271 case 27:
2272 while (ssh->userpass_input_bufpos > 0) {
2273 if (ssh->userpass_input_echo)
2274 c_write_str(ssh, "\b \b");
2275 ssh->userpass_input_bufpos--;
2276 }
2277 break;
2278 case 3:
2279 case 4:
2280 return -1;
2281 break;
2282 default:
2283 /*
2284 * This simplistic check for printability is disabled
2285 * when we're doing password input, because some people
2286 * have control characters in their passwords.o
2287 */
2288 if ((!ssh->userpass_input_echo ||
2289 (c >= ' ' && c <= '~') ||
2290 ((unsigned char) c >= 160))
2291 && ssh->userpass_input_bufpos < ssh->userpass_input_buflen-1) {
2292 ssh->userpass_input_buffer[ssh->userpass_input_bufpos++] = c;
2293 if (ssh->userpass_input_echo)
2294 c_write(ssh, &c, 1);
2295 }
2296 break;
2297 }
2298 }
2299 return 0;
2300 }
2301
2302 static void ssh_agent_callback(void *sshv, void *reply, int replylen)
2303 {
2304 Ssh ssh = (Ssh) sshv;
2305
2306 ssh->agent_response = reply;
2307 ssh->agent_response_len = replylen;
2308
2309 if (ssh->version == 1)
2310 do_ssh1_login(ssh, NULL, -1, 0);
2311 else
2312 do_ssh2_authconn(ssh, NULL, -1, 0);
2313 }
2314
2315 static void ssh_agentf_callback(void *cv, void *reply, int replylen)
2316 {
2317 struct ssh_channel *c = (struct ssh_channel *)cv;
2318 Ssh ssh = c->ssh;
2319 void *sentreply = reply;
2320
2321 if (!sentreply) {
2322 /* Fake SSH_AGENT_FAILURE. */
2323 sentreply = "\0\0\0\1\5";
2324 replylen = 5;
2325 }
2326 if (ssh->version == 2) {
2327 ssh2_add_channel_data(c, sentreply, replylen);
2328 ssh2_try_send(c);
2329 } else {
2330 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
2331 PKT_INT, c->remoteid,
2332 PKT_INT, replylen,
2333 PKT_DATA, sentreply, replylen,
2334 PKT_END);
2335 }
2336 if (reply)
2337 sfree(reply);
2338 }
2339
2340 /*
2341 * Handle the key exchange and user authentication phases.
2342 */
2343 static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
2344 {
2345 int i, j;
2346 unsigned char cookie[8];
2347 struct RSAKey servkey, hostkey;
2348 struct MD5Context md5c;
2349 struct do_ssh1_login_state {
2350 int len;
2351 unsigned char *rsabuf, *keystr1, *keystr2;
2352 unsigned long supported_ciphers_mask, supported_auths_mask;
2353 int tried_publickey, tried_agent;
2354 int tis_auth_refused, ccard_auth_refused;
2355 unsigned char session_id[16];
2356 int cipher_type;
2357 char username[100];
2358 void *publickey_blob;
2359 int publickey_bloblen;
2360 char password[100];
2361 char prompt[200];
2362 int pos;
2363 char c;
2364 int pwpkt_type;
2365 unsigned char request[5], *response, *p;
2366 int responselen;
2367 int keyi, nkeys;
2368 int authed;
2369 struct RSAKey key;
2370 Bignum challenge;
2371 char *commentp;
2372 int commentlen;
2373 };
2374 crState(do_ssh1_login_state);
2375
2376 crBegin(ssh->do_ssh1_login_crstate);
2377
2378 if (!ispkt)
2379 crWaitUntil(ispkt);
2380
2381 if (ssh->pktin.type != SSH1_SMSG_PUBLIC_KEY) {
2382 bombout(("Public key packet not received"));
2383 crStop(0);
2384 }
2385
2386 logevent("Received public keys");
2387
2388 memcpy(cookie, ssh->pktin.body, 8);
2389
2390 i = makekey(ssh->pktin.body + 8, &servkey, &s->keystr1, 0);
2391 j = makekey(ssh->pktin.body + 8 + i, &hostkey, &s->keystr2, 0);
2392
2393 /*
2394 * Log the host key fingerprint.
2395 */
2396 {
2397 char logmsg[80];
2398 logevent("Host key fingerprint is:");
2399 strcpy(logmsg, " ");
2400 hostkey.comment = NULL;
2401 rsa_fingerprint(logmsg + strlen(logmsg),
2402 sizeof(logmsg) - strlen(logmsg), &hostkey);
2403 logevent(logmsg);
2404 }
2405
2406 ssh->v1_remote_protoflags = GET_32BIT(ssh->pktin.body + 8 + i + j);
2407 s->supported_ciphers_mask = GET_32BIT(ssh->pktin.body + 12 + i + j);
2408 s->supported_auths_mask = GET_32BIT(ssh->pktin.body + 16 + i + j);
2409
2410 ssh->v1_local_protoflags =
2411 ssh->v1_remote_protoflags & SSH1_PROTOFLAGS_SUPPORTED;
2412 ssh->v1_local_protoflags |= SSH1_PROTOFLAG_SCREEN_NUMBER;
2413
2414 MD5Init(&md5c);
2415 MD5Update(&md5c, s->keystr2, hostkey.bytes);
2416 MD5Update(&md5c, s->keystr1, servkey.bytes);
2417 MD5Update(&md5c, ssh->pktin.body, 8);
2418 MD5Final(s->session_id, &md5c);
2419
2420 for (i = 0; i < 32; i++)
2421 ssh->session_key[i] = random_byte();
2422
2423 s->len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes);
2424
2425 s->rsabuf = snewn(s->len, unsigned char);
2426 if (!s->rsabuf)
2427 fatalbox("Out of memory");
2428
2429 /*
2430 * Verify the host key.
2431 */
2432 {
2433 /*
2434 * First format the key into a string.
2435 */
2436 int len = rsastr_len(&hostkey);
2437 char fingerprint[100];
2438 char *keystr = snewn(len, char);
2439 if (!keystr)
2440 fatalbox("Out of memory");
2441 rsastr_fmt(keystr, &hostkey);
2442 rsa_fingerprint(fingerprint, sizeof(fingerprint), &hostkey);
2443 verify_ssh_host_key(ssh->frontend,
2444 ssh->savedhost, ssh->savedport, "rsa", keystr,
2445 fingerprint);
2446 sfree(keystr);
2447 }
2448
2449 for (i = 0; i < 32; i++) {
2450 s->rsabuf[i] = ssh->session_key[i];
2451 if (i < 16)
2452 s->rsabuf[i] ^= s->session_id[i];
2453 }
2454
2455 if (hostkey.bytes > servkey.bytes) {
2456 rsaencrypt(s->rsabuf, 32, &servkey);
2457 rsaencrypt(s->rsabuf, servkey.bytes, &hostkey);
2458 } else {
2459 rsaencrypt(s->rsabuf, 32, &hostkey);
2460 rsaencrypt(s->rsabuf, hostkey.bytes, &servkey);
2461 }
2462
2463 logevent("Encrypted session key");
2464
2465 {
2466 int cipher_chosen = 0, warn = 0;
2467 char *cipher_string = NULL;
2468 int i;
2469 for (i = 0; !cipher_chosen && i < CIPHER_MAX; i++) {
2470 int next_cipher = ssh->cfg.ssh_cipherlist[i];
2471 if (next_cipher == CIPHER_WARN) {
2472 /* If/when we choose a cipher, warn about it */
2473 warn = 1;
2474 } else if (next_cipher == CIPHER_AES) {
2475 /* XXX Probably don't need to mention this. */
2476 logevent("AES not supported in SSH1, skipping");
2477 } else {
2478 switch (next_cipher) {
2479 case CIPHER_3DES: s->cipher_type = SSH_CIPHER_3DES;
2480 cipher_string = "3DES"; break;
2481 case CIPHER_BLOWFISH: s->cipher_type = SSH_CIPHER_BLOWFISH;
2482 cipher_string = "Blowfish"; break;
2483 case CIPHER_DES: s->cipher_type = SSH_CIPHER_DES;
2484 cipher_string = "single-DES"; break;
2485 }
2486 if (s->supported_ciphers_mask & (1 << s->cipher_type))
2487 cipher_chosen = 1;
2488 }
2489 }
2490 if (!cipher_chosen) {
2491 if ((s->supported_ciphers_mask & (1 << SSH_CIPHER_3DES)) == 0)
2492 bombout(("Server violates SSH 1 protocol by not "
2493 "supporting 3DES encryption"));
2494 else
2495 /* shouldn't happen */
2496 bombout(("No supported ciphers found"));
2497 crStop(0);
2498 }
2499
2500 /* Warn about chosen cipher if necessary. */
2501 if (warn)
2502 askcipher(ssh->frontend, cipher_string, 0);
2503 }
2504
2505 switch (s->cipher_type) {
2506 case SSH_CIPHER_3DES:
2507 logevent("Using 3DES encryption");
2508 break;
2509 case SSH_CIPHER_DES:
2510 logevent("Using single-DES encryption");
2511 break;
2512 case SSH_CIPHER_BLOWFISH:
2513 logevent("Using Blowfish encryption");
2514 break;
2515 }
2516
2517 send_packet(ssh, SSH1_CMSG_SESSION_KEY,
2518 PKT_CHAR, s->cipher_type,
2519 PKT_DATA, cookie, 8,
2520 PKT_CHAR, (s->len * 8) >> 8, PKT_CHAR, (s->len * 8) & 0xFF,
2521 PKT_DATA, s->rsabuf, s->len,
2522 PKT_INT, ssh->v1_local_protoflags, PKT_END);
2523
2524 logevent("Trying to enable encryption...");
2525
2526 sfree(s->rsabuf);
2527
2528 ssh->cipher = (s->cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 :
2529 s->cipher_type == SSH_CIPHER_DES ? &ssh_des :
2530 &ssh_3des);
2531 ssh->v1_cipher_ctx = ssh->cipher->make_context();
2532 ssh->cipher->sesskey(ssh->v1_cipher_ctx, ssh->session_key);
2533 logeventf(ssh, "Initialised %s encryption", ssh->cipher->text_name);
2534
2535 ssh->crcda_ctx = crcda_make_context();
2536 logevent("Installing CRC compensation attack detector");
2537
2538 if (servkey.modulus) {
2539 sfree(servkey.modulus);
2540 servkey.modulus = NULL;
2541 }
2542 if (servkey.exponent) {
2543 sfree(servkey.exponent);
2544 servkey.exponent = NULL;
2545 }
2546 if (hostkey.modulus) {
2547 sfree(hostkey.modulus);
2548 hostkey.modulus = NULL;
2549 }
2550 if (hostkey.exponent) {
2551 sfree(hostkey.exponent);
2552 hostkey.exponent = NULL;
2553 }
2554 crWaitUntil(ispkt);
2555
2556 if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
2557 bombout(("Encryption not successfully enabled"));
2558 crStop(0);
2559 }
2560
2561 logevent("Successfully started encryption");
2562
2563 fflush(stdout);
2564 {
2565 if ((flags & FLAG_INTERACTIVE) && !*ssh->cfg.username) {
2566 if (ssh_get_line && !ssh_getline_pw_only) {
2567 if (!ssh_get_line("login as: ",
2568 s->username, sizeof(s->username), FALSE)) {
2569 /*
2570 * get_line failed to get a username.
2571 * Terminate.
2572 */
2573 logevent("No username provided. Abandoning session.");
2574 ssh_closing((Plug)ssh, NULL, 0, 0);
2575 crStop(1);
2576 }
2577 } else {
2578 int ret; /* need not be kept over crReturn */
2579 c_write_str(ssh, "login as: ");
2580 ssh->send_ok = 1;
2581
2582 setup_userpass_input(ssh, s->username, sizeof(s->username), 1);
2583 do {
2584 crWaitUntil(!ispkt);
2585 ret = process_userpass_input(ssh, in, inlen);
2586 } while (ret == 0);
2587 if (ret < 0)
2588 cleanup_exit(0);
2589 c_write_str(ssh, "\r\n");
2590 }
2591 } else {
2592 strncpy(s->username, ssh->cfg.username, sizeof(s->username));
2593 s->username[sizeof(s->username)-1] = '\0';
2594 }
2595
2596 send_packet(ssh, SSH1_CMSG_USER, PKT_STR, s->username, PKT_END);
2597 {
2598 char userlog[22 + sizeof(s->username)];
2599 sprintf(userlog, "Sent username \"%s\"", s->username);
2600 logevent(userlog);
2601 if (flags & FLAG_INTERACTIVE &&
2602 (!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) {
2603 strcat(userlog, "\r\n");
2604 c_write_str(ssh, userlog);
2605 }
2606 }
2607 }
2608
2609 crWaitUntil(ispkt);
2610
2611 if ((ssh->remote_bugs & BUG_CHOKES_ON_RSA)) {
2612 /* We must not attempt PK auth. Pretend we've already tried it. */
2613 s->tried_publickey = s->tried_agent = 1;
2614 } else {
2615 s->tried_publickey = s->tried_agent = 0;
2616 }
2617 s->tis_auth_refused = s->ccard_auth_refused = 0;
2618 /* Load the public half of ssh->cfg.keyfile so we notice if it's in Pageant */
2619 if (!filename_is_null(ssh->cfg.keyfile)) {
2620 if (!rsakey_pubblob(&ssh->cfg.keyfile,
2621 &s->publickey_blob, &s->publickey_bloblen, NULL))
2622 s->publickey_blob = NULL;
2623 } else
2624 s->publickey_blob = NULL;
2625
2626 while (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2627 s->pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
2628
2629 if (agent_exists() && !s->tried_agent) {
2630 /*
2631 * Attempt RSA authentication using Pageant.
2632 */
2633 void *r;
2634
2635 s->authed = FALSE;
2636 s->tried_agent = 1;
2637 logevent("Pageant is running. Requesting keys.");
2638
2639 /* Request the keys held by the agent. */
2640 PUT_32BIT(s->request, 1);
2641 s->request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES;
2642 if (!agent_query(s->request, 5, &r, &s->responselen,
2643 ssh_agent_callback, ssh)) {
2644 do {
2645 crReturn(0);
2646 if (ispkt) {
2647 bombout(("Unexpected data from server while waiting"
2648 " for agent response"));
2649 crStop(0);
2650 }
2651 } while (ispkt || inlen > 0);
2652 r = ssh->agent_response;
2653 s->responselen = ssh->agent_response_len;
2654 }
2655 s->response = (unsigned char *) r;
2656 if (s->response && s->responselen >= 5 &&
2657 s->response[4] == SSH1_AGENT_RSA_IDENTITIES_ANSWER) {
2658 s->p = s->response + 5;
2659 s->nkeys = GET_32BIT(s->p);
2660 s->p += 4;
2661 {
2662 char buf[64];
2663 sprintf(buf, "Pageant has %d SSH1 keys", s->nkeys);
2664 logevent(buf);
2665 }
2666 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
2667 {
2668 char buf[64];
2669 sprintf(buf, "Trying Pageant key #%d", s->keyi);
2670 logevent(buf);
2671 }
2672 if (s->publickey_blob &&
2673 !memcmp(s->p, s->publickey_blob,
2674 s->publickey_bloblen)) {
2675 logevent("This key matches configured key file");
2676 s->tried_publickey = 1;
2677 }
2678 s->p += 4;
2679 s->p += ssh1_read_bignum(s->p, &s->key.exponent);
2680 s->p += ssh1_read_bignum(s->p, &s->key.modulus);
2681 s->commentlen = GET_32BIT(s->p);
2682 s->p += 4;
2683 s->commentp = (char *)s->p;
2684 s->p += s->commentlen;
2685 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
2686 PKT_BIGNUM, s->key.modulus, PKT_END);
2687 crWaitUntil(ispkt);
2688 if (ssh->pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
2689 logevent("Key refused");
2690 continue;
2691 }
2692 logevent("Received RSA challenge");
2693 ssh1_read_bignum(ssh->pktin.body, &s->challenge);
2694 {
2695 char *agentreq, *q, *ret;
2696 void *vret;
2697 int len, retlen;
2698 len = 1 + 4; /* message type, bit count */
2699 len += ssh1_bignum_length(s->key.exponent);
2700 len += ssh1_bignum_length(s->key.modulus);
2701 len += ssh1_bignum_length(s->challenge);
2702 len += 16; /* session id */
2703 len += 4; /* response format */
2704 agentreq = snewn(4 + len, char);
2705 PUT_32BIT(agentreq, len);
2706 q = agentreq + 4;
2707 *q++ = SSH1_AGENTC_RSA_CHALLENGE;
2708 PUT_32BIT(q, bignum_bitcount(s->key.modulus));
2709 q += 4;
2710 q += ssh1_write_bignum(q, s->key.exponent);
2711 q += ssh1_write_bignum(q, s->key.modulus);
2712 q += ssh1_write_bignum(q, s->challenge);
2713 memcpy(q, s->session_id, 16);
2714 q += 16;
2715 PUT_32BIT(q, 1); /* response format */
2716 if (!agent_query(agentreq, len + 4, &vret, &retlen,
2717 ssh_agent_callback, ssh)) {
2718 sfree(agentreq);
2719 do {
2720 crReturn(0);
2721 if (ispkt) {
2722 bombout(("Unexpected data from server"
2723 " while waiting for agent"
2724 " response"));
2725 crStop(0);
2726 }
2727 } while (ispkt || inlen > 0);
2728 vret = ssh->agent_response;
2729 retlen = ssh->agent_response_len;
2730 } else
2731 sfree(agentreq);
2732 ret = vret;
2733 if (ret) {
2734 if (ret[4] == SSH1_AGENT_RSA_RESPONSE) {
2735 logevent("Sending Pageant's response");
2736 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
2737 PKT_DATA, ret + 5, 16,
2738 PKT_END);
2739 sfree(ret);
2740 crWaitUntil(ispkt);
2741 if (ssh->pktin.type == SSH1_SMSG_SUCCESS) {
2742 logevent
2743 ("Pageant's response accepted");
2744 if (flags & FLAG_VERBOSE) {
2745 c_write_str(ssh, "Authenticated using"
2746 " RSA key \"");
2747 c_write(ssh, s->commentp,
2748 s->commentlen);
2749 c_write_str(ssh, "\" from agent\r\n");
2750 }
2751 s->authed = TRUE;
2752 } else
2753 logevent
2754 ("Pageant's response not accepted");
2755 } else {
2756 logevent
2757 ("Pageant failed to answer challenge");
2758 sfree(ret);
2759 }
2760 } else {
2761 logevent("No reply received from Pageant");
2762 }
2763 }
2764 freebn(s->key.exponent);
2765 freebn(s->key.modulus);
2766 freebn(s->challenge);
2767 if (s->authed)
2768 break;
2769 }
2770 }
2771 if (s->authed)
2772 break;
2773 }
2774 if (!filename_is_null(ssh->cfg.keyfile) && !s->tried_publickey)
2775 s->pwpkt_type = SSH1_CMSG_AUTH_RSA;
2776
2777 if (ssh->cfg.try_tis_auth &&
2778 (s->supported_auths_mask & (1 << SSH1_AUTH_TIS)) &&
2779 !s->tis_auth_refused) {
2780 s->pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
2781 logevent("Requested TIS authentication");
2782 send_packet(ssh, SSH1_CMSG_AUTH_TIS, PKT_END);
2783 crWaitUntil(ispkt);
2784 if (ssh->pktin.type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
2785 logevent("TIS authentication declined");
2786 if (flags & FLAG_INTERACTIVE)
2787 c_write_str(ssh, "TIS authentication refused.\r\n");
2788 s->tis_auth_refused = 1;
2789 continue;
2790 } else {
2791 int challengelen = GET_32BIT(ssh->pktin.body);
2792 logevent("Received TIS challenge");
2793 if (challengelen > sizeof(s->prompt) - 1)
2794 challengelen = sizeof(s->prompt) - 1;/* prevent overrun */
2795 memcpy(s->prompt, ssh->pktin.body + 4, challengelen);
2796 /* Prompt heuristic comes from OpenSSH */
2797 strncpy(s->prompt + challengelen,
2798 memchr(s->prompt, '\n', challengelen) ?
2799 "": "\r\nResponse: ",
2800 (sizeof s->prompt) - challengelen);
2801 s->prompt[(sizeof s->prompt) - 1] = '\0';
2802 }
2803 }
2804 if (ssh->cfg.try_tis_auth &&
2805 (s->supported_auths_mask & (1 << SSH1_AUTH_CCARD)) &&
2806 !s->ccard_auth_refused) {
2807 s->pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE;
2808 logevent("Requested CryptoCard authentication");
2809 send_packet(ssh, SSH1_CMSG_AUTH_CCARD, PKT_END);
2810 crWaitUntil(ispkt);
2811 if (ssh->pktin.type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
2812 logevent("CryptoCard authentication declined");
2813 c_write_str(ssh, "CryptoCard authentication refused.\r\n");
2814 s->ccard_auth_refused = 1;
2815 continue;
2816 } else {
2817 int challengelen = GET_32BIT(ssh->pktin.body);
2818 logevent("Received CryptoCard challenge");
2819 if (challengelen > sizeof(s->prompt) - 1)
2820 challengelen = sizeof(s->prompt) - 1;/* prevent overrun */
2821 memcpy(s->prompt, ssh->pktin.body + 4, challengelen);
2822 strncpy(s->prompt + challengelen,
2823 memchr(s->prompt, '\n', challengelen) ?
2824 "" : "\r\nResponse: ",
2825 sizeof(s->prompt) - challengelen);
2826 s->prompt[sizeof(s->prompt) - 1] = '\0';
2827 }
2828 }
2829 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
2830 sprintf(s->prompt, "%.90s@%.90s's password: ",
2831 s->username, ssh->savedhost);
2832 }
2833 if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) {
2834 char *comment = NULL;
2835 int type;
2836 char msgbuf[256];
2837 if (flags & FLAG_VERBOSE)
2838 c_write_str(ssh, "Trying public key authentication.\r\n");
2839 logeventf(ssh, "Trying public key \"%s\"",
2840 filename_to_str(&ssh->cfg.keyfile));
2841 type = key_type(&ssh->cfg.keyfile);
2842 if (type != SSH_KEYTYPE_SSH1) {
2843 sprintf(msgbuf, "Key is of wrong type (%s)",
2844 key_type_to_str(type));
2845 logevent(msgbuf);
2846 c_write_str(ssh, msgbuf);
2847 c_write_str(ssh, "\r\n");
2848 s->tried_publickey = 1;
2849 continue;
2850 }
2851 if (!rsakey_encrypted(&ssh->cfg.keyfile, &comment)) {
2852 if (flags & FLAG_VERBOSE)
2853 c_write_str(ssh, "No passphrase required.\r\n");
2854 goto tryauth;
2855 }
2856 sprintf(s->prompt, "Passphrase for key \"%.100s\": ", comment);
2857 sfree(comment);
2858 }
2859
2860 /*
2861 * Show password prompt, having first obtained it via a TIS
2862 * or CryptoCard exchange if we're doing TIS or CryptoCard
2863 * authentication.
2864 */
2865 if (ssh_get_line) {
2866 if (!ssh_get_line(s->prompt, s->password,
2867 sizeof(s->password), TRUE)) {
2868 /*
2869 * get_line failed to get a password (for example
2870 * because one was supplied on the command line
2871 * which has already failed to work). Terminate.
2872 */
2873 send_packet(ssh, SSH1_MSG_DISCONNECT,
2874 PKT_STR, "No more passwords available to try",
2875 PKT_END);
2876 logevent("Unable to authenticate");
2877 connection_fatal(ssh->frontend, "Unable to authenticate");
2878 ssh_closing((Plug)ssh, NULL, 0, 0);
2879 crStop(1);
2880 }
2881 } else {
2882 /* Prompt may have come from server. We've munged it a bit, so
2883 * we know it to be zero-terminated at least once. */
2884 int ret; /* need not be saved over crReturn */
2885 c_write_untrusted(ssh, s->prompt, strlen(s->prompt));
2886 s->pos = 0;
2887
2888 setup_userpass_input(ssh, s->password, sizeof(s->password), 0);
2889 do {
2890 crWaitUntil(!ispkt);
2891 ret = process_userpass_input(ssh, in, inlen);
2892 } while (ret == 0);
2893 if (ret < 0)
2894 cleanup_exit(0);
2895 c_write_str(ssh, "\r\n");
2896 }
2897
2898 tryauth:
2899 if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) {
2900 /*
2901 * Try public key authentication with the specified
2902 * key file.
2903 */
2904 s->tried_publickey = 1;
2905
2906 {
2907 const char *error = NULL;
2908 int ret = loadrsakey(&ssh->cfg.keyfile, &s->key, s->password,
2909 &error);
2910 if (ret == 0) {
2911 c_write_str(ssh, "Couldn't load private key from ");
2912 c_write_str(ssh, filename_to_str(&ssh->cfg.keyfile));
2913 c_write_str(ssh, " (");
2914 c_write_str(ssh, error);
2915 c_write_str(ssh, ").\r\n");
2916 continue; /* go and try password */
2917 }
2918 if (ret == -1) {
2919 c_write_str(ssh, "Wrong passphrase.\r\n");
2920 s->tried_publickey = 0;
2921 continue; /* try again */
2922 }
2923 }
2924
2925 /*
2926 * Send a public key attempt.
2927 */
2928 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
2929 PKT_BIGNUM, s->key.modulus, PKT_END);
2930
2931 crWaitUntil(ispkt);
2932 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2933 c_write_str(ssh, "Server refused our public key.\r\n");
2934 continue; /* go and try password */
2935 }
2936 if (ssh->pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
2937 bombout(("Bizarre response to offer of public key"));
2938 crStop(0);
2939 }
2940
2941 {
2942 int i;
2943 unsigned char buffer[32];
2944 Bignum challenge, response;
2945
2946 ssh1_read_bignum(ssh->pktin.body, &challenge);
2947 response = rsadecrypt(challenge, &s->key);
2948 freebn(s->key.private_exponent);/* burn the evidence */
2949
2950 for (i = 0; i < 32; i++) {
2951 buffer[i] = bignum_byte(response, 31 - i);
2952 }
2953
2954 MD5Init(&md5c);
2955 MD5Update(&md5c, buffer, 32);
2956 MD5Update(&md5c, s->session_id, 16);
2957 MD5Final(buffer, &md5c);
2958
2959 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
2960 PKT_DATA, buffer, 16, PKT_END);
2961
2962 freebn(challenge);
2963 freebn(response);
2964 }
2965
2966 crWaitUntil(ispkt);
2967 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2968 if (flags & FLAG_VERBOSE)
2969 c_write_str(ssh, "Failed to authenticate with"
2970 " our public key.\r\n");
2971 continue; /* go and try password */
2972 } else if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
2973 bombout(("Bizarre response to RSA authentication response"));
2974 crStop(0);
2975 }
2976
2977 break; /* we're through! */
2978 } else {
2979 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
2980 /*
2981 * Defence against traffic analysis: we send a
2982 * whole bunch of packets containing strings of
2983 * different lengths. One of these strings is the
2984 * password, in a SSH1_CMSG_AUTH_PASSWORD packet.
2985 * The others are all random data in
2986 * SSH1_MSG_IGNORE packets. This way a passive
2987 * listener can't tell which is the password, and
2988 * hence can't deduce the password length.
2989 *
2990 * Anybody with a password length greater than 16
2991 * bytes is going to have enough entropy in their
2992 * password that a listener won't find it _that_
2993 * much help to know how long it is. So what we'll
2994 * do is:
2995 *
2996 * - if password length < 16, we send 15 packets
2997 * containing string lengths 1 through 15
2998 *
2999 * - otherwise, we let N be the nearest multiple
3000 * of 8 below the password length, and send 8
3001 * packets containing string lengths N through
3002 * N+7. This won't obscure the order of
3003 * magnitude of the password length, but it will
3004 * introduce a bit of extra uncertainty.
3005 *
3006 * A few servers (the old 1.2.18 through 1.2.22)
3007 * can't deal with SSH1_MSG_IGNORE. For these
3008 * servers, we need an alternative defence. We make
3009 * use of the fact that the password is interpreted
3010 * as a C string: so we can append a NUL, then some
3011 * random data.
3012 *
3013 * One server (a Cisco one) can deal with neither
3014 * SSH1_MSG_IGNORE _nor_ a padded password string.
3015 * For this server we are left with no defences
3016 * against password length sniffing.
3017 */
3018 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE)) {
3019 /*
3020 * The server can deal with SSH1_MSG_IGNORE, so
3021 * we can use the primary defence.
3022 */
3023 int bottom, top, pwlen, i;
3024 char *randomstr;
3025
3026 pwlen = strlen(s->password);
3027 if (pwlen < 16) {
3028 bottom = 0; /* zero length passwords are OK! :-) */
3029 top = 15;
3030 } else {
3031 bottom = pwlen & ~7;
3032 top = bottom + 7;
3033 }
3034
3035 assert(pwlen >= bottom && pwlen <= top);
3036
3037 randomstr = snewn(top + 1, char);
3038
3039 for (i = bottom; i <= top; i++) {
3040 if (i == pwlen)
3041 defer_packet(ssh, s->pwpkt_type,
3042 PKT_STR, s->password, PKT_END);
3043 else {
3044 for (j = 0; j < i; j++) {
3045 do {
3046 randomstr[j] = random_byte();
3047 } while (randomstr[j] == '\0');
3048 }
3049 randomstr[i] = '\0';
3050 defer_packet(ssh, SSH1_MSG_IGNORE,
3051 PKT_STR, randomstr, PKT_END);
3052 }
3053 }
3054 logevent("Sending password with camouflage packets");
3055 ssh_pkt_defersend(ssh);
3056 sfree(randomstr);
3057 }
3058 else if (!(ssh->remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) {
3059 /*
3060 * The server can't deal with SSH1_MSG_IGNORE
3061 * but can deal with padded passwords, so we
3062 * can use the secondary defence.
3063 */
3064 char string[64];
3065 char *ss;
3066 int len;
3067
3068 len = strlen(s->password);
3069 if (len < sizeof(string)) {
3070 ss = string;
3071 strcpy(string, s->password);
3072 len++; /* cover the zero byte */
3073 while (len < sizeof(string)) {
3074 string[len++] = (char) random_byte();
3075 }
3076 } else {
3077 ss = s->password;
3078 }
3079 logevent("Sending length-padded password");
3080 send_packet(ssh, s->pwpkt_type, PKT_INT, len,
3081 PKT_DATA, ss, len, PKT_END);
3082 } else {
3083 /*
3084 * The server has _both_
3085 * BUG_CHOKES_ON_SSH1_IGNORE and
3086 * BUG_NEEDS_SSH1_PLAIN_PASSWORD. There is
3087 * therefore nothing we can do.
3088 */
3089 int len;
3090 len = strlen(s->password);
3091 logevent("Sending unpadded password");
3092 send_packet(ssh, s->pwpkt_type, PKT_INT, len,
3093 PKT_DATA, s->password, len, PKT_END);
3094 }
3095 } else {
3096 send_packet(ssh, s->pwpkt_type, PKT_STR, s->password, PKT_END);
3097 }
3098 }
3099 logevent("Sent password");
3100 memset(s->password, 0, strlen(s->password));
3101 crWaitUntil(ispkt);
3102 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3103 if (flags & FLAG_VERBOSE)
3104 c_write_str(ssh, "Access denied\r\n");
3105 logevent("Authentication refused");
3106 } else if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
3107 bombout(("Strange packet received, type %d", ssh->pktin.type));
3108 crStop(0);
3109 }
3110 }
3111
3112 logevent("Authentication successful");
3113
3114 crFinish(1);
3115 }
3116
3117 void sshfwd_close(struct ssh_channel *c)
3118 {
3119 Ssh ssh = c->ssh;
3120
3121 if (ssh->state != SSH_STATE_SESSION) {
3122 assert(ssh->state == SSH_STATE_CLOSED);
3123 return;
3124 }
3125
3126 if (c && !c->closes) {
3127 /*
3128 * If the channel's remoteid is -1, we have sent
3129 * CHANNEL_OPEN for this channel, but it hasn't even been
3130 * acknowledged by the server. So we must set a close flag
3131 * on it now, and then when the server acks the channel
3132 * open, we can close it then.
3133 */
3134 if (((int)c->remoteid) != -1) {
3135 if (ssh->version == 1) {
3136 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid,
3137 PKT_END);
3138 } else {
3139 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
3140 ssh2_pkt_adduint32(ssh, c->remoteid);
3141 ssh2_pkt_send(ssh);
3142 }
3143 }
3144 c->closes = 1; /* sent MSG_CLOSE */
3145 if (c->type == CHAN_X11) {
3146 c->u.x11.s = NULL;
3147 logevent("Forwarded X11 connection terminated");
3148 } else if (c->type == CHAN_SOCKDATA ||
3149 c->type == CHAN_SOCKDATA_DORMANT) {
3150 c->u.pfd.s = NULL;
3151 logevent("Forwarded port closed");
3152 }
3153 }
3154 }
3155
3156 int sshfwd_write(struct ssh_channel *c, char *buf, int len)
3157 {
3158 Ssh ssh = c->ssh;
3159
3160 if (ssh->state != SSH_STATE_SESSION) {
3161 assert(ssh->state == SSH_STATE_CLOSED);
3162 return 0;
3163 }
3164
3165 if (ssh->version == 1) {
3166 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
3167 PKT_INT, c->remoteid,
3168 PKT_INT, len, PKT_DATA, buf, len, PKT_END);
3169 /*
3170 * In SSH1 we can return 0 here - implying that forwarded
3171 * connections are never individually throttled - because
3172 * the only circumstance that can cause throttling will be
3173 * the whole SSH connection backing up, in which case
3174 * _everything_ will be throttled as a whole.
3175 */
3176 return 0;
3177 } else {
3178 ssh2_add_channel_data(c, buf, len);
3179 return ssh2_try_send(c);
3180 }
3181 }
3182
3183 void sshfwd_unthrottle(struct ssh_channel *c, int bufsize)
3184 {
3185 Ssh ssh = c->ssh;
3186
3187 if (ssh->state != SSH_STATE_SESSION) {
3188 assert(ssh->state == SSH_STATE_CLOSED);
3189 return;
3190 }
3191
3192 if (ssh->version == 1) {
3193 if (c->v.v1.throttling && bufsize < SSH1_BUFFER_LIMIT) {
3194 c->v.v1.throttling = 0;
3195 ssh1_throttle(ssh, -1);
3196 }
3197 } else {
3198 ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
3199 }
3200 }
3201
3202 static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
3203 {
3204 crBegin(ssh->ssh1_protocol_crstate);
3205
3206 random_init();
3207
3208 while (!do_ssh1_login(ssh, in, inlen, ispkt)) {
3209 crReturnV;
3210 }
3211 if (ssh->state == SSH_STATE_CLOSED)
3212 crReturnV;
3213
3214 if (ssh->cfg.agentfwd && agent_exists()) {
3215 logevent("Requesting agent forwarding");
3216 send_packet(ssh, SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END);
3217 do {
3218 crReturnV;
3219 } while (!ispkt);
3220 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3221 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3222 bombout(("Protocol confusion"));
3223 crStopV;
3224 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3225 logevent("Agent forwarding refused");
3226 } else {
3227 logevent("Agent forwarding enabled");
3228 ssh->agentfwd_enabled = TRUE;
3229 }
3230 }
3231
3232 if (ssh->cfg.x11_forward) {
3233 char proto[20], data[64];
3234 logevent("Requesting X11 forwarding");
3235 ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
3236 data, sizeof(data), ssh->cfg.x11_auth);
3237 x11_get_real_auth(ssh->x11auth, ssh->cfg.x11_display);
3238 if (ssh->v1_local_protoflags & SSH1_PROTOFLAG_SCREEN_NUMBER) {
3239 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
3240 PKT_STR, proto, PKT_STR, data,
3241 PKT_INT, x11_get_screen_number(ssh->cfg.x11_display),
3242 PKT_END);
3243 } else {
3244 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
3245 PKT_STR, proto, PKT_STR, data, PKT_END);
3246 }
3247 do {
3248 crReturnV;
3249 } while (!ispkt);
3250 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3251 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3252 bombout(("Protocol confusion"));
3253 crStopV;
3254 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3255 logevent("X11 forwarding refused");
3256 } else {
3257 logevent("X11 forwarding enabled");
3258 ssh->X11_fwd_enabled = TRUE;
3259 }
3260 }
3261
3262 {
3263 char type;
3264 int n;
3265 int sport,dport,sserv,dserv;
3266 char sports[256], dports[256], saddr[256], host[256];
3267
3268 ssh->rportfwds = newtree234(ssh_rportcmp_ssh1);
3269 /* Add port forwardings. */
3270 ssh->portfwd_strptr = ssh->cfg.portfwd;
3271 while (*ssh->portfwd_strptr) {
3272 type = *ssh->portfwd_strptr++;
3273 saddr[0] = '\0';
3274 n = 0;
3275 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != '\t') {
3276 if (*ssh->portfwd_strptr == ':') {
3277 /*
3278 * We've seen a colon in the middle of the
3279 * source port number. This means that
3280 * everything we've seen until now is the
3281 * source _address_, so we'll move it into
3282 * saddr and start sports from the beginning
3283 * again.
3284 */
3285 ssh->portfwd_strptr++;
3286 sports[n] = '\0';
3287 strcpy(saddr, sports);
3288 n = 0;
3289 }
3290 if (n < 255) sports[n++] = *ssh->portfwd_strptr++;
3291 }
3292 sports[n] = 0;
3293 if (type != 'D') {
3294 if (*ssh->portfwd_strptr == '\t')
3295 ssh->portfwd_strptr++;
3296 n = 0;
3297 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':') {
3298 if (n < 255) host[n++] = *ssh->portfwd_strptr++;
3299 }
3300 host[n] = 0;
3301 if (*ssh->portfwd_strptr == ':')
3302 ssh->portfwd_strptr++;
3303 n = 0;
3304 while (*ssh->portfwd_strptr) {
3305 if (n < 255) dports[n++] = *ssh->portfwd_strptr++;
3306 }
3307 dports[n] = 0;
3308 ssh->portfwd_strptr++;
3309 dport = atoi(dports);
3310 dserv = 0;
3311 if (dport == 0) {
3312 dserv = 1;
3313 dport = net_service_lookup(dports);
3314 if (!dport) {
3315 logeventf(ssh, "Service lookup failed for"
3316 " destination port \"%s\"", dports);
3317 }
3318 }
3319 } else {
3320 while (*ssh->portfwd_strptr) ssh->portfwd_strptr++;
3321 dport = dserv = -1;
3322 ssh->portfwd_strptr++; /* eat the NUL and move to next one */
3323 }
3324 sport = atoi(sports);
3325 sserv = 0;
3326 if (sport == 0) {
3327 sserv = 1;
3328 sport = net_service_lookup(sports);
3329 if (!sport) {
3330 logeventf(ssh, "Service lookup failed for source"
3331 " port \"%s\"", sports);
3332 }
3333 }
3334 if (sport && dport) {
3335 if (type == 'L') {
3336 pfd_addforward(host, dport, *saddr ? saddr : NULL,
3337 sport, ssh, &ssh->cfg);
3338 logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
3339 " forwarding to %s:%.*s%.*s%d%.*s",
3340 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
3341 (int)(*saddr?1:0), ":",
3342 (int)(sserv ? strlen(sports) : 0), sports,
3343 sserv, "(", sport, sserv, ")",
3344 host,
3345 (int)(dserv ? strlen(dports) : 0), dports,
3346 dserv, "(", dport, dserv, ")");
3347 } else if (type == 'D') {
3348 pfd_addforward(NULL, -1, *saddr ? saddr : NULL,
3349 sport, ssh, &ssh->cfg);
3350 logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
3351 " doing SOCKS dynamic forwarding",
3352 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
3353 (int)(*saddr?1:0), ":",
3354 (int)(sserv ? strlen(sports) : 0), sports,
3355 sserv, "(", sport, sserv, ")");
3356 } else {
3357 struct ssh_rportfwd *pf;
3358 pf = snew(struct ssh_rportfwd);
3359 strcpy(pf->dhost, host);
3360 pf->dport = dport;
3361 if (saddr) {
3362 logeventf(ssh,
3363 "SSH1 cannot handle source address spec \"%s:%d\"; ignoring",
3364 saddr, sport);
3365 }
3366 if (add234(ssh->rportfwds, pf) != pf) {
3367 logeventf(ssh,
3368 "Duplicate remote port forwarding to %s:%d",
3369 host, dport);
3370 sfree(pf);
3371 } else {
3372 logeventf(ssh, "Requesting remote port %.*s%.*s%d%.*s"
3373 " forward to %s:%.*s%.*s%d%.*s",
3374 (int)(sserv ? strlen(sports) : 0), sports,
3375 sserv, "(", sport, sserv, ")",
3376 host,
3377 (int)(dserv ? strlen(dports) : 0), dports,
3378 dserv, "(", dport, dserv, ")");
3379 send_packet(ssh, SSH1_CMSG_PORT_FORWARD_REQUEST,
3380 PKT_INT, sport,
3381 PKT_STR, host,
3382 PKT_INT, dport,
3383 PKT_END);
3384 do {
3385 crReturnV;
3386 } while (!ispkt);
3387 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3388 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3389 bombout(("Protocol confusion"));
3390 crStopV;
3391 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3392 c_write_str(ssh, "Server refused port"
3393 " forwarding\r\n");
3394 }
3395 logevent("Remote port forwarding enabled");
3396 }
3397 }
3398 }
3399 }
3400 }
3401
3402 if (!ssh->cfg.nopty) {
3403 send_packet(ssh, SSH1_CMSG_REQUEST_PTY,
3404 PKT_STR, ssh->cfg.termtype,
3405 PKT_INT, ssh->term_height,
3406 PKT_INT, ssh->term_width,
3407 PKT_INT, 0, PKT_INT, 0, PKT_CHAR, 0, PKT_END);
3408 ssh->state = SSH_STATE_INTERMED;
3409 do {
3410 crReturnV;
3411 } while (!ispkt);
3412 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3413 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3414 bombout(("Protocol confusion"));
3415 crStopV;
3416 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3417 c_write_str(ssh, "Server refused to allocate pty\r\n");
3418 ssh->editing = ssh->echoing = 1;
3419 }
3420 logevent("Allocated pty");
3421 } else {
3422 ssh->editing = ssh->echoing = 1;
3423 }
3424
3425 if (ssh->cfg.compression) {
3426 send_packet(ssh, SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END);
3427 do {
3428 crReturnV;
3429 } while (!ispkt);
3430 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3431 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3432 bombout(("Protocol confusion"));
3433 crStopV;
3434 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3435 c_write_str(ssh, "Server refused to compress\r\n");
3436 }
3437 logevent("Started compression");
3438 ssh->v1_compressing = TRUE;
3439 ssh->cs_comp_ctx = zlib_compress_init();
3440 logevent("Initialised zlib (RFC1950) compression");
3441 ssh->sc_comp_ctx = zlib_decompress_init();
3442 logevent("Initialised zlib (RFC1950) decompression");
3443 }
3444
3445 /*
3446 * Start the shell or command.
3447 *
3448 * Special case: if the first-choice command is an SSH2
3449 * subsystem (hence not usable here) and the second choice
3450 * exists, we fall straight back to that.
3451 */
3452 {
3453 char *cmd = ssh->cfg.remote_cmd_ptr;
3454
3455 if (ssh->cfg.ssh_subsys && ssh->cfg.remote_cmd_ptr2) {
3456 cmd = ssh->cfg.remote_cmd_ptr2;
3457 ssh->fallback_cmd = TRUE;
3458 }
3459 if (*cmd)
3460 send_packet(ssh, SSH1_CMSG_EXEC_CMD, PKT_STR, cmd, PKT_END);
3461 else
3462 send_packet(ssh, SSH1_CMSG_EXEC_SHELL, PKT_END);
3463 logevent("Started session");
3464 }
3465
3466 ssh->state = SSH_STATE_SESSION;
3467 if (ssh->size_needed)
3468 ssh_size(ssh, ssh->term_width, ssh->term_height);
3469 if (ssh->eof_needed)
3470 ssh_special(ssh, TS_EOF);
3471
3472 if (ssh->ldisc)
3473 ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */
3474 ssh->send_ok = 1;
3475 ssh->channels = newtree234(ssh_channelcmp);
3476 while (1) {
3477 crReturnV;
3478 if (ispkt) {
3479 if (ssh->pktin.type == SSH1_SMSG_STDOUT_DATA ||
3480 ssh->pktin.type == SSH1_SMSG_STDERR_DATA) {
3481 long len = GET_32BIT(ssh->pktin.body);
3482 int bufsize =
3483 from_backend(ssh->frontend,
3484 ssh->pktin.type == SSH1_SMSG_STDERR_DATA,
3485 (char *)(ssh->pktin.body) + 4, len);
3486 if (!ssh->v1_stdout_throttling && bufsize > SSH1_BUFFER_LIMIT) {
3487 ssh->v1_stdout_throttling = 1;
3488 ssh1_throttle(ssh, +1);
3489 }
3490 } else if (ssh->pktin.type == SSH1_MSG_DISCONNECT) {
3491 ssh_closing((Plug)ssh, NULL, 0, 0);
3492 logevent("Received disconnect request");
3493 crStopV;
3494 } else if (ssh->pktin.type == SSH1_SMSG_X11_OPEN) {
3495 /* Remote side is trying to open a channel to talk to our
3496 * X-Server. Give them back a local channel number. */
3497 struct ssh_channel *c;
3498
3499 logevent("Received X11 connect request");
3500 /* Refuse if X11 forwarding is disabled. */
3501 if (!ssh->X11_fwd_enabled) {
3502 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3503 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
3504 logevent("Rejected X11 connect request");
3505 } else {
3506 c = snew(struct ssh_channel);
3507 c->ssh = ssh;
3508
3509 if (x11_init(&c->u.x11.s, ssh->cfg.x11_display, c,
3510 ssh->x11auth, NULL, -1, &ssh->cfg) != NULL) {
3511 logevent("opening X11 forward connection failed");
3512 sfree(c);
3513 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3514 PKT_INT, GET_32BIT(ssh->pktin.body),
3515 PKT_END);
3516 } else {
3517 logevent
3518 ("opening X11 forward connection succeeded");
3519 c->remoteid = GET_32BIT(ssh->pktin.body);
3520 c->localid = alloc_channel_id(ssh);
3521 c->closes = 0;
3522 c->v.v1.throttling = 0;
3523 c->type = CHAN_X11; /* identify channel type */
3524 add234(ssh->channels, c);
3525 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3526 PKT_INT, c->remoteid, PKT_INT,
3527 c->localid, PKT_END);
3528 logevent("Opened X11 forward channel");
3529 }
3530 }
3531 } else if (ssh->pktin.type == SSH1_SMSG_AGENT_OPEN) {
3532 /* Remote side is trying to open a channel to talk to our
3533 * agent. Give them back a local channel number. */
3534 struct ssh_channel *c;
3535
3536 /* Refuse if agent forwarding is disabled. */
3537 if (!ssh->agentfwd_enabled) {
3538 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3539 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
3540 } else {
3541 c = snew(struct ssh_channel);
3542 c->ssh = ssh;
3543 c->remoteid = GET_32BIT(ssh->pktin.body);
3544 c->localid = alloc_channel_id(ssh);
3545 c->closes = 0;
3546 c->v.v1.throttling = 0;
3547 c->type = CHAN_AGENT; /* identify channel type */
3548 c->u.a.lensofar = 0;
3549 add234(ssh->channels, c);
3550 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3551 PKT_INT, c->remoteid, PKT_INT, c->localid,
3552 PKT_END);
3553 }
3554 } else if (ssh->pktin.type == SSH1_MSG_PORT_OPEN) {
3555 /* Remote side is trying to open a channel to talk to a
3556 * forwarded port. Give them back a local channel number. */
3557 struct ssh_channel *c;
3558 struct ssh_rportfwd pf;
3559 int hostsize, port;
3560 char host[256], buf[1024];
3561 char *p, *h;
3562 const char *e;
3563 c = snew(struct ssh_channel);
3564 c->ssh = ssh;
3565
3566 hostsize = GET_32BIT(ssh->pktin.body+4);
3567 for (h = host, p = (char *)(ssh->pktin.body+8);
3568 hostsize != 0; hostsize--) {
3569 if (h+1 < host+sizeof(host))
3570 *h++ = *p;
3571 p++;
3572 }
3573 *h = 0;
3574 port = GET_32BIT(p);
3575
3576 strcpy(pf.dhost, host);
3577 pf.dport = port;
3578
3579 if (find234(ssh->rportfwds, &pf, NULL) == NULL) {
3580 sprintf(buf, "Rejected remote port open request for %s:%d",
3581 host, port);
3582 logevent(buf);
3583 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3584 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
3585 } else {
3586 sprintf(buf, "Received remote port open request for %s:%d",
3587 host, port);
3588 logevent(buf);
3589 e = pfd_newconnect(&c->u.pfd.s, host, port, c, &ssh->cfg);
3590 if (e != NULL) {
3591 char buf[256];
3592 sprintf(buf, "Port open failed: %s", e);
3593 logevent(buf);
3594 sfree(c);
3595 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3596 PKT_INT, GET_32BIT(ssh->pktin.body),
3597 PKT_END);
3598 } else {
3599 c->remoteid = GET_32BIT(ssh->pktin.body);
3600 c->localid = alloc_channel_id(ssh);
3601 c->closes = 0;
3602 c->v.v1.throttling = 0;
3603 c->type = CHAN_SOCKDATA; /* identify channel type */
3604 add234(ssh->channels, c);
3605 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3606 PKT_INT, c->remoteid, PKT_INT,
3607 c->localid, PKT_END);
3608 logevent("Forwarded port opened successfully");
3609 }
3610 }
3611
3612 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_OPEN_CONFIRMATION) {
3613 unsigned int remoteid = GET_32BIT(ssh->pktin.body);
3614 unsigned int localid = GET_32BIT(ssh->pktin.body+4);
3615 struct ssh_channel *c;
3616
3617 c = find234(ssh->channels, &remoteid, ssh_channelfind);
3618 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
3619 c->remoteid = localid;
3620 c->type = CHAN_SOCKDATA;
3621 c->v.v1.throttling = 0;
3622 pfd_confirm(c->u.pfd.s);
3623 }
3624
3625 if (c && c->closes) {
3626 /*
3627 * We have a pending close on this channel,
3628 * which we decided on before the server acked
3629 * the channel open. So now we know the
3630 * remoteid, we can close it again.
3631 */
3632 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE,
3633 PKT_INT, c->remoteid, PKT_END);
3634 }
3635
3636 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_OPEN_FAILURE) {
3637 unsigned int remoteid = GET_32BIT(ssh->pktin.body);
3638 struct ssh_channel *c;
3639
3640 c = find234(ssh->channels, &remoteid, ssh_channelfind);
3641 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
3642 logevent("Forwarded connection refused by server");
3643 pfd_close(c->u.pfd.s);
3644 del234(ssh->channels, c);
3645 sfree(c);
3646 }
3647
3648 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ||
3649 ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION) {
3650 /* Remote side closes a channel. */
3651 unsigned i = GET_32BIT(ssh->pktin.body);
3652 struct ssh_channel *c;
3653 c = find234(ssh->channels, &i, ssh_channelfind);
3654 if (c && ((int)c->remoteid) != -1) {
3655 int closetype;
3656 closetype =
3657 (ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ? 1 : 2);
3658
3659 if ((c->closes == 0) && (c->type == CHAN_X11)) {
3660 logevent("Forwarded X11 connection terminated");
3661 assert(c->u.x11.s != NULL);
3662 x11_close(c->u.x11.s);
3663 c->u.x11.s = NULL;
3664 }
3665 if ((c->closes == 0) && (c->type == CHAN_SOCKDATA)) {
3666 logevent("Forwarded port closed");
3667 assert(c->u.pfd.s != NULL);
3668 pfd_close(c->u.pfd.s);
3669 c->u.pfd.s = NULL;
3670 }
3671
3672 c->closes |= (closetype << 2); /* seen this message */
3673 if (!(c->closes & closetype)) {
3674 send_packet(ssh, ssh->pktin.type, PKT_INT, c->remoteid,
3675 PKT_END);
3676 c->closes |= closetype; /* sent it too */
3677 }
3678
3679 if (c->closes == 15) {
3680 del234(ssh->channels, c);
3681 sfree(c);
3682 }
3683 } else {
3684 bombout(("Received CHANNEL_CLOSE%s for %s channel %d\n",
3685 ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ? "" :
3686 "_CONFIRMATION", c ? "half-open" : "nonexistent",
3687 i));
3688 crStopV;
3689 }
3690 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_DATA) {
3691 /* Data sent down one of our channels. */
3692 int i = GET_32BIT(ssh->pktin.body);
3693 int len = GET_32BIT(ssh->pktin.body + 4);
3694 unsigned char *p = ssh->pktin.body + 8;
3695 struct ssh_channel *c;
3696 c = find234(ssh->channels, &i, ssh_channelfind);
3697 if (c) {
3698 int bufsize = 0;
3699 switch (c->type) {
3700 case CHAN_X11:
3701 bufsize = x11_send(c->u.x11.s, (char *)p, len);
3702 break;
3703 case CHAN_SOCKDATA:
3704 bufsize = pfd_send(c->u.pfd.s, (char *)p, len);
3705 break;
3706 case CHAN_AGENT:
3707 /* Data for an agent message. Buffer it. */
3708 while (len > 0) {
3709 if (c->u.a.lensofar < 4) {
3710 int l = min(4 - c->u.a.lensofar, len);
3711 memcpy(c->u.a.msglen + c->u.a.lensofar, p,
3712 l);
3713 p += l;
3714 len -= l;
3715 c->u.a.lensofar += l;
3716 }
3717 if (c->u.a.lensofar == 4) {
3718 c->u.a.totallen =
3719 4 + GET_32BIT(c->u.a.msglen);
3720 c->u.a.message = snewn(c->u.a.totallen,
3721 unsigned char);
3722 memcpy(c->u.a.message, c->u.a.msglen, 4);
3723 }
3724 if (c->u.a.lensofar >= 4 && len > 0) {
3725 int l =
3726 min(c->u.a.totallen - c->u.a.lensofar,
3727 len);
3728 memcpy(c->u.a.message + c->u.a.lensofar, p,
3729 l);
3730 p += l;
3731 len -= l;
3732 c->u.a.lensofar += l;
3733 }
3734 if (c->u.a.lensofar == c->u.a.totallen) {
3735 void *reply;
3736 int replylen;
3737 if (agent_query(c->u.a.message,
3738 c->u.a.totallen,
3739 &reply, &replylen,
3740 ssh_agentf_callback, c))
3741 ssh_agentf_callback(c, reply, replylen);
3742 sfree(c->u.a.message);
3743 c->u.a.lensofar = 0;
3744 }
3745 }
3746 bufsize = 0; /* agent channels never back up */
3747 break;
3748 }
3749 if (!c->v.v1.throttling && bufsize > SSH1_BUFFER_LIMIT) {
3750 c->v.v1.throttling = 1;
3751 ssh1_throttle(ssh, +1);
3752 }
3753 }
3754 } else if (ssh->pktin.type == SSH1_SMSG_SUCCESS) {
3755 /* may be from EXEC_SHELL on some servers */
3756 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3757 /* may be from EXEC_SHELL on some servers
3758 * if no pty is available or in other odd cases. Ignore */
3759 } else if (ssh->pktin.type == SSH1_SMSG_EXIT_STATUS) {
3760 char buf[100];
3761 ssh->exitcode = GET_32BIT(ssh->pktin.body);
3762 sprintf(buf, "Server sent command exit status %d",
3763 ssh->exitcode);
3764 logevent(buf);
3765 send_packet(ssh, SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
3766 /*
3767 * In case `helpful' firewalls or proxies tack
3768 * extra human-readable text on the end of the
3769 * session which we might mistake for another
3770 * encrypted packet, we close the session once
3771 * we've sent EXIT_CONFIRMATION.
3772 */
3773 ssh_closing((Plug)ssh, NULL, 0, 0);
3774 crStopV;
3775 } else {
3776 bombout(("Strange packet received: type %d", ssh->pktin.type));
3777 crStopV;
3778 }
3779 } else {
3780 while (inlen > 0) {
3781 int len = min(inlen, 512);
3782 send_packet(ssh, SSH1_CMSG_STDIN_DATA,
3783 PKT_INT, len, PKT_DATA, in, len, PKT_END);
3784 in += len;
3785 inlen -= len;
3786 }
3787 }
3788 }
3789
3790 crFinishV;
3791 }
3792
3793 /*
3794 * Utility routine for decoding comma-separated strings in KEXINIT.
3795 */
3796 static int in_commasep_string(char *needle, char *haystack, int haylen)
3797 {
3798 int needlen;
3799 if (!needle || !haystack) /* protect against null pointers */
3800 return 0;
3801 needlen = strlen(needle);
3802 while (1) {
3803 /*
3804 * Is it at the start of the string?
3805 */
3806 if (haylen >= needlen && /* haystack is long enough */
3807 !memcmp(needle, haystack, needlen) && /* initial match */
3808 (haylen == needlen || haystack[needlen] == ',')
3809 /* either , or EOS follows */
3810 )
3811 return 1;
3812 /*
3813 * If not, search for the next comma and resume after that.
3814 * If no comma found, terminate.
3815 */
3816 while (haylen > 0 && *haystack != ',')
3817 haylen--, haystack++;
3818 if (haylen == 0)
3819 return 0;
3820 haylen--, haystack++; /* skip over comma itself */
3821 }
3822 }
3823
3824 /*
3825 * SSH2 key creation method.
3826 */
3827 static void ssh2_mkkey(Ssh ssh, Bignum K, unsigned char *H,
3828 unsigned char *sessid, char chr,
3829 unsigned char *keyspace)
3830 {
3831 SHA_State s;
3832 /* First 20 bytes. */
3833 SHA_Init(&s);
3834 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
3835 sha_mpint(&s, K);
3836 SHA_Bytes(&s, H, 20);
3837 SHA_Bytes(&s, &chr, 1);
3838 SHA_Bytes(&s, sessid, 20);
3839 SHA_Final(&s, keyspace);
3840 /* Next 20 bytes. */
3841 SHA_Init(&s);
3842 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
3843 sha_mpint(&s, K);
3844 SHA_Bytes(&s, H, 20);
3845 SHA_Bytes(&s, keyspace, 20);
3846 SHA_Final(&s, keyspace + 20);
3847 }
3848
3849 /*
3850 * Handle the SSH2 transport layer.
3851 */
3852 static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
3853 {
3854 struct do_ssh2_transport_state {
3855 int nbits, pbits, warn;
3856 Bignum p, g, e, f, K;
3857 int kex_init_value, kex_reply_value;
3858 const struct ssh_mac **maclist;
3859 int nmacs;
3860 const struct ssh2_cipher *cscipher_tobe;
3861 const struct ssh2_cipher *sccipher_tobe;
3862 const struct ssh_mac *csmac_tobe;
3863 const struct ssh_mac *scmac_tobe;
3864 const struct ssh_compress *cscomp_tobe;
3865 const struct ssh_compress *sccomp_tobe;
3866 char *hostkeydata, *sigdata, *keystr, *fingerprint;
3867 int hostkeylen, siglen;
3868 void *hkey; /* actual host key */
3869 unsigned char exchange_hash[20];
3870 int n_preferred_ciphers;
3871 const struct ssh2_ciphers *preferred_ciphers[CIPHER_MAX];
3872 const struct ssh_compress *preferred_comp;
3873 int first_kex;
3874 };
3875 crState(do_ssh2_transport_state);
3876
3877 crBegin(ssh->do_ssh2_transport_crstate);
3878
3879 s->cscipher_tobe = s->sccipher_tobe = NULL;
3880 s->csmac_tobe = s->scmac_tobe = NULL;
3881 s->cscomp_tobe = s->sccomp_tobe = NULL;
3882
3883 random_init();
3884 s->first_kex = 1;
3885
3886 {
3887 int i;
3888 /*
3889 * Set up the preferred ciphers. (NULL => warn below here)
3890 */
3891 s->n_preferred_ciphers = 0;
3892 for (i = 0; i < CIPHER_MAX; i++) {
3893 switch (ssh->cfg.ssh_cipherlist[i]) {
3894 case CIPHER_BLOWFISH:
3895 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_blowfish;
3896 break;
3897 case CIPHER_DES:
3898 if (ssh->cfg.ssh2_des_cbc) {
3899 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_des;
3900 }
3901 break;
3902 case CIPHER_3DES:
3903 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_3des;
3904 break;
3905 case CIPHER_AES:
3906 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_aes;
3907 break;
3908 case CIPHER_WARN:
3909 /* Flag for later. Don't bother if it's the last in
3910 * the list. */
3911 if (i < CIPHER_MAX - 1) {
3912 s->preferred_ciphers[s->n_preferred_ciphers++] = NULL;
3913 }
3914 break;
3915 }
3916 }
3917 }
3918
3919 /*
3920 * Set up preferred compression.
3921 */
3922 if (ssh->cfg.compression)
3923 s->preferred_comp = &ssh_zlib;
3924 else
3925 s->preferred_comp = &ssh_comp_none;
3926
3927 /*
3928 * Be prepared to work around the buggy MAC problem.
3929 */
3930 if (ssh->remote_bugs & BUG_SSH2_HMAC)
3931 s->maclist = buggymacs, s->nmacs = lenof(buggymacs);
3932 else
3933 s->maclist = macs, s->nmacs = lenof(macs);
3934
3935 begin_key_exchange:
3936 {
3937 int i, j, cipherstr_started;
3938
3939 /*
3940 * Construct and send our key exchange packet.
3941 */
3942 ssh2_pkt_init(ssh, SSH2_MSG_KEXINIT);
3943 for (i = 0; i < 16; i++)
3944 ssh2_pkt_addbyte(ssh, (unsigned char) random_byte());
3945 /* List key exchange algorithms. */
3946 ssh2_pkt_addstring_start(ssh);
3947 for (i = 0; i < lenof(kex_algs); i++) {
3948 if (kex_algs[i] == &ssh_diffiehellman_gex &&
3949 (ssh->remote_bugs & BUG_SSH2_DH_GEX))
3950 continue;
3951 ssh2_pkt_addstring_str(ssh, kex_algs[i]->name);
3952 if (i < lenof(kex_algs) - 1)
3953 ssh2_pkt_addstring_str(ssh, ",");
3954 }
3955 /* List server host key algorithms. */
3956 ssh2_pkt_addstring_start(ssh);
3957 for (i = 0; i < lenof(hostkey_algs); i++) {
3958 ssh2_pkt_addstring_str(ssh, hostkey_algs[i]->name);
3959 if (i < lenof(hostkey_algs) - 1)
3960 ssh2_pkt_addstring_str(ssh, ",");
3961 }
3962 /* List client->server encryption algorithms. */
3963 ssh2_pkt_addstring_start(ssh);
3964 cipherstr_started = 0;
3965 for (i = 0; i < s->n_preferred_ciphers; i++) {
3966 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3967 if (!c) continue; /* warning flag */
3968 for (j = 0; j < c->nciphers; j++) {
3969 if (cipherstr_started)
3970 ssh2_pkt_addstring_str(ssh, ",");
3971 ssh2_pkt_addstring_str(ssh, c->list[j]->name);
3972 cipherstr_started = 1;
3973 }
3974 }
3975 /* List server->client encryption algorithms. */
3976 ssh2_pkt_addstring_start(ssh);
3977 cipherstr_started = 0;
3978 for (i = 0; i < s->n_preferred_ciphers; i++) {
3979 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3980 if (!c) continue; /* warning flag */
3981 for (j = 0; j < c->nciphers; j++) {
3982 if (cipherstr_started)
3983 ssh2_pkt_addstring_str(ssh, ",");
3984 ssh2_pkt_addstring_str(ssh, c->list[j]->name);
3985 cipherstr_started = 1;
3986 }
3987 }
3988 /* List client->server MAC algorithms. */
3989 ssh2_pkt_addstring_start(ssh);
3990 for (i = 0; i < s->nmacs; i++) {
3991 ssh2_pkt_addstring_str(ssh, s->maclist[i]->name);
3992 if (i < s->nmacs - 1)
3993 ssh2_pkt_addstring_str(ssh, ",");
3994 }
3995 /* List server->client MAC algorithms. */
3996 ssh2_pkt_addstring_start(ssh);
3997 for (i = 0; i < s->nmacs; i++) {
3998 ssh2_pkt_addstring_str(ssh, s->maclist[i]->name);
3999 if (i < s->nmacs - 1)
4000 ssh2_pkt_addstring_str(ssh, ",");
4001 }
4002 /* List client->server compression algorithms. */
4003 ssh2_pkt_addstring_start(ssh);
4004 for (i = 0; i < lenof(compressions) + 1; i++) {
4005 const struct ssh_compress *c =
4006 i == 0 ? s->preferred_comp : compressions[i - 1];
4007 ssh2_pkt_addstring_str(ssh, c->name);
4008 if (i < lenof(compressions))
4009 ssh2_pkt_addstring_str(ssh, ",");
4010 }
4011 /* List server->client compression algorithms. */
4012 ssh2_pkt_addstring_start(ssh);
4013 for (i = 0; i < lenof(compressions) + 1; i++) {
4014 const struct ssh_compress *c =
4015 i == 0 ? s->preferred_comp : compressions[i - 1];
4016 ssh2_pkt_addstring_str(ssh, c->name);
4017 if (i < lenof(compressions))
4018 ssh2_pkt_addstring_str(ssh, ",");
4019 }
4020 /* List client->server languages. Empty list. */
4021 ssh2_pkt_addstring_start(ssh);
4022 /* List server->client languages. Empty list. */
4023 ssh2_pkt_addstring_start(ssh);
4024 /* First KEX packet does _not_ follow, because we're not that brave. */
4025 ssh2_pkt_addbool(ssh, FALSE);
4026 /* Reserved. */
4027 ssh2_pkt_adduint32(ssh, 0);
4028 }
4029
4030 ssh->exhash = ssh->exhashbase;
4031 sha_string(&ssh->exhash, ssh->pktout.data + 5, ssh->pktout.length - 5);
4032
4033 ssh2_pkt_send(ssh);
4034
4035 if (!ispkt)
4036 crWaitUntil(ispkt);
4037 if (ssh->pktin.length > 5)
4038 sha_string(&ssh->exhash, ssh->pktin.data + 5, ssh->pktin.length - 5);
4039
4040 /*
4041 * Now examine the other side's KEXINIT to see what we're up
4042 * to.
4043 */
4044 {
4045 char *str;
4046 int i, j, len;
4047
4048 if (ssh->pktin.type != SSH2_MSG_KEXINIT) {
4049 bombout(("expected key exchange packet from server"));
4050 crStop(0);
4051 }
4052 ssh->kex = NULL;
4053 ssh->hostkey = NULL;
4054 s->cscipher_tobe = NULL;
4055 s->sccipher_tobe = NULL;
4056 s->csmac_tobe = NULL;
4057 s->scmac_tobe = NULL;
4058 s->cscomp_tobe = NULL;
4059 s->sccomp_tobe = NULL;
4060 ssh->pktin.savedpos += 16; /* skip garbage cookie */
4061 ssh2_pkt_getstring(ssh, &str, &len); /* key exchange algorithms */
4062 for (i = 0; i < lenof(kex_algs); i++) {
4063 if (kex_algs[i] == &ssh_diffiehellman_gex &&
4064 (ssh->remote_bugs & BUG_SSH2_DH_GEX))
4065 continue;
4066 if (in_commasep_string(kex_algs[i]->name, str, len)) {
4067 ssh->kex = kex_algs[i];
4068 break;
4069 }
4070 }
4071 ssh2_pkt_getstring(ssh, &str, &len); /* host key algorithms */
4072 for (i = 0; i < lenof(hostkey_algs); i++) {
4073 if (in_commasep_string(hostkey_algs[i]->name, str, len)) {
4074 ssh->hostkey = hostkey_algs[i];
4075 break;
4076 }
4077 }
4078 ssh2_pkt_getstring(ssh, &str, &len); /* client->server cipher */
4079 s->warn = 0;
4080 for (i = 0; i < s->n_preferred_ciphers; i++) {
4081 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
4082 if (!c) {
4083 s->warn = 1;
4084 } else {
4085 for (j = 0; j < c->nciphers; j++) {
4086 if (in_commasep_string(c->list[j]->name, str, len)) {
4087 s->cscipher_tobe = c->list[j];
4088 break;
4089 }
4090 }
4091 }
4092 if (s->cscipher_tobe) {
4093 if (s->warn)
4094 askcipher(ssh->frontend, s->cscipher_tobe->name, 1);
4095 break;
4096 }
4097 }
4098 if (!s->cscipher_tobe) {
4099 bombout(("Couldn't agree a client-to-server cipher (available: %s)",
4100 str ? str : "(null)"));
4101 crStop(0);
4102 }
4103
4104 ssh2_pkt_getstring(ssh, &str, &len); /* server->client cipher */
4105 s->warn = 0;
4106 for (i = 0; i < s->n_preferred_ciphers; i++) {
4107 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
4108 if (!c) {
4109 s->warn = 1;
4110 } else {
4111 for (j = 0; j < c->nciphers; j++) {
4112 if (in_commasep_string(c->list[j]->name, str, len)) {
4113 s->sccipher_tobe = c->list[j];
4114 break;
4115 }
4116 }
4117 }
4118 if (s->sccipher_tobe) {
4119 if (s->warn)
4120 askcipher(ssh->frontend, s->sccipher_tobe->name, 2);
4121 break;
4122 }
4123 }
4124 if (!s->sccipher_tobe) {
4125 bombout(("Couldn't agree a server-to-client cipher (available: %s)",
4126 str ? str : "(null)"));
4127 crStop(0);
4128 }
4129
4130 ssh2_pkt_getstring(ssh, &str, &len); /* client->server mac */
4131 for (i = 0; i < s->nmacs; i++) {
4132 if (in_commasep_string(s->maclist[i]->name, str, len)) {
4133 s->csmac_tobe = s->maclist[i];
4134 break;
4135 }
4136 }
4137 ssh2_pkt_getstring(ssh, &str, &len); /* server->client mac */
4138 for (i = 0; i < s->nmacs; i++) {
4139 if (in_commasep_string(s->maclist[i]->name, str, len)) {
4140 s->scmac_tobe = s->maclist[i];
4141 break;
4142 }
4143 }
4144 ssh2_pkt_getstring(ssh, &str, &len); /* client->server compression */
4145 for (i = 0; i < lenof(compressions) + 1; i++) {
4146 const struct ssh_compress *c =
4147 i == 0 ? s->preferred_comp : compressions[i - 1];
4148 if (in_commasep_string(c->name, str, len)) {
4149 s->cscomp_tobe = c;
4150 break;
4151 }
4152 }
4153 ssh2_pkt_getstring(ssh, &str, &len); /* server->client compression */
4154 for (i = 0; i < lenof(compressions) + 1; i++) {
4155 const struct ssh_compress *c =
4156 i == 0 ? s->preferred_comp : compressions[i - 1];
4157 if (in_commasep_string(c->name, str, len)) {
4158 s->sccomp_tobe = c;
4159 break;
4160 }
4161 }
4162 }
4163
4164 /*
4165 * Work out the number of bits of key we will need from the key
4166 * exchange. We start with the maximum key length of either
4167 * cipher...
4168 */
4169 {
4170 int csbits, scbits;
4171
4172 csbits = s->cscipher_tobe->keylen;
4173 scbits = s->sccipher_tobe->keylen;
4174 s->nbits = (csbits > scbits ? csbits : scbits);
4175 }
4176 /* The keys only have 160-bit entropy, since they're based on
4177 * a SHA-1 hash. So cap the key size at 160 bits. */
4178 if (s->nbits > 160)
4179 s->nbits = 160;
4180
4181 /*
4182 * If we're doing Diffie-Hellman group exchange, start by
4183 * requesting a group.
4184 */
4185 if (ssh->kex == &ssh_diffiehellman_gex) {
4186 logevent("Doing Diffie-Hellman group exchange");
4187 ssh->pkt_ctx |= SSH2_PKTCTX_DHGEX;
4188 /*
4189 * Work out how big a DH group we will need to allow that
4190 * much data.
4191 */
4192 s->pbits = 512 << ((s->nbits - 1) / 64);
4193 ssh2_pkt_init(ssh, SSH2_MSG_KEX_DH_GEX_REQUEST);
4194 ssh2_pkt_adduint32(ssh, s->pbits);
4195 ssh2_pkt_send(ssh);
4196
4197 crWaitUntil(ispkt);
4198 if (ssh->pktin.type != SSH2_MSG_KEX_DH_GEX_GROUP) {
4199 bombout(("expected key exchange group packet from server"));
4200 crStop(0);
4201 }
4202 s->p = ssh2_pkt_getmp(ssh);
4203 s->g = ssh2_pkt_getmp(ssh);
4204 ssh->kex_ctx = dh_setup_group(s->p, s->g);
4205 s->kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT;
4206 s->kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY;
4207 } else {
4208 ssh->pkt_ctx |= SSH2_PKTCTX_DHGROUP1;
4209 ssh->kex_ctx = dh_setup_group1();
4210 s->kex_init_value = SSH2_MSG_KEXDH_INIT;
4211 s->kex_reply_value = SSH2_MSG_KEXDH_REPLY;
4212 }
4213
4214 logevent("Doing Diffie-Hellman key exchange");
4215 /*
4216 * Now generate and send e for Diffie-Hellman.
4217 */
4218 s->e = dh_create_e(ssh->kex_ctx, s->nbits * 2);
4219 ssh2_pkt_init(ssh, s->kex_init_value);
4220 ssh2_pkt_addmp(ssh, s->e);
4221 ssh2_pkt_send(ssh);
4222
4223 crWaitUntil(ispkt);
4224 if (ssh->pktin.type != s->kex_reply_value) {
4225 bombout(("expected key exchange reply packet from server"));
4226 crStop(0);
4227 }
4228 ssh2_pkt_getstring(ssh, &s->hostkeydata, &s->hostkeylen);
4229 s->f = ssh2_pkt_getmp(ssh);
4230 ssh2_pkt_getstring(ssh, &s->sigdata, &s->siglen);
4231
4232 s->K = dh_find_K(ssh->kex_ctx, s->f);
4233
4234 sha_string(&ssh->exhash, s->hostkeydata, s->hostkeylen);
4235 if (ssh->kex == &ssh_diffiehellman_gex) {
4236 sha_uint32(&ssh->exhash, s->pbits);
4237 sha_mpint(&ssh->exhash, s->p);
4238 sha_mpint(&ssh->exhash, s->g);
4239 }
4240 sha_mpint(&ssh->exhash, s->e);
4241 sha_mpint(&ssh->exhash, s->f);
4242 sha_mpint(&ssh->exhash, s->K);
4243 SHA_Final(&ssh->exhash, s->exchange_hash);
4244
4245 dh_cleanup(ssh->kex_ctx);
4246 ssh->kex_ctx = NULL;
4247
4248 #if 0
4249 debug(("Exchange hash is:\n"));
4250 dmemdump(s->exchange_hash, 20);
4251 #endif
4252
4253 s->hkey = ssh->hostkey->newkey(s->hostkeydata, s->hostkeylen);
4254 if (!s->hkey ||
4255 !ssh->hostkey->verifysig(s->hkey, s->sigdata, s->siglen,
4256 (char *)s->exchange_hash, 20)) {
4257 bombout(("Server's host key did not match the signature supplied"));
4258 crStop(0);
4259 }
4260
4261 /*
4262 * Authenticate remote host: verify host key. (We've already
4263 * checked the signature of the exchange hash.)
4264 */
4265 s->keystr = ssh->hostkey->fmtkey(s->hkey);
4266 s->fingerprint = ssh->hostkey->fingerprint(s->hkey);
4267 verify_ssh_host_key(ssh->frontend,
4268 ssh->savedhost, ssh->savedport, ssh->hostkey->keytype,
4269 s->keystr, s->fingerprint);
4270 if (s->first_kex) { /* don't bother logging this in rekeys */
4271 logevent("Host key fingerprint is:");
4272 logevent(s->fingerprint);
4273 }
4274 sfree(s->fingerprint);
4275 sfree(s->keystr);
4276 ssh->hostkey->freekey(s->hkey);
4277
4278 /*
4279 * Send SSH2_MSG_NEWKEYS.
4280 */
4281 ssh2_pkt_init(ssh, SSH2_MSG_NEWKEYS);
4282 ssh2_pkt_send(ssh);
4283
4284 /*
4285 * Expect SSH2_MSG_NEWKEYS from server.
4286 */
4287 crWaitUntil(ispkt);
4288 if (ssh->pktin.type != SSH2_MSG_NEWKEYS) {
4289 bombout(("expected new-keys packet from server"));
4290 crStop(0);
4291 }
4292
4293 /*
4294 * Create and initialise session keys.
4295 */
4296 if (ssh->cs_cipher_ctx)
4297 ssh->cscipher->free_context(ssh->cs_cipher_ctx);
4298 ssh->cscipher = s->cscipher_tobe;
4299 ssh->cs_cipher_ctx = ssh->cscipher->make_context();
4300
4301 if (ssh->sc_cipher_ctx)
4302 ssh->sccipher->free_context(ssh->sc_cipher_ctx);
4303 ssh->sccipher = s->sccipher_tobe;
4304 ssh->sc_cipher_ctx = ssh->sccipher->make_context();
4305
4306 if (ssh->cs_mac_ctx)
4307 ssh->csmac->free_context(ssh->cs_mac_ctx);
4308 ssh->csmac = s->csmac_tobe;
4309 ssh->cs_mac_ctx = ssh->csmac->make_context();
4310
4311 if (ssh->sc_mac_ctx)
4312 ssh->scmac->free_context(ssh->sc_mac_ctx);
4313 ssh->scmac = s->scmac_tobe;
4314 ssh->sc_mac_ctx = ssh->scmac->make_context();
4315
4316 if (ssh->cs_comp_ctx)
4317 ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
4318 ssh->cscomp = s->cscomp_tobe;
4319 ssh->cs_comp_ctx = ssh->cscomp->compress_init();
4320
4321 if (ssh->sc_comp_ctx)
4322 ssh->sccomp->decompress_cleanup(ssh->sc_comp_ctx);
4323 ssh->sccomp = s->sccomp_tobe;
4324 ssh->sc_comp_ctx = ssh->sccomp->decompress_init();
4325
4326 /*
4327 * Set IVs after keys. Here we use the exchange hash from the
4328 * _first_ key exchange.
4329 */
4330 {
4331 unsigned char keyspace[40];
4332 if (s->first_kex)
4333 memcpy(ssh->v2_session_id, s->exchange_hash,
4334 sizeof(s->exchange_hash));
4335 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'C',keyspace);
4336 ssh->cscipher->setkey(ssh->cs_cipher_ctx, keyspace);
4337 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'D',keyspace);
4338 ssh->sccipher->setkey(ssh->sc_cipher_ctx, keyspace);
4339 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'A',keyspace);
4340 ssh->cscipher->setiv(ssh->cs_cipher_ctx, keyspace);
4341 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'B',keyspace);
4342 ssh->sccipher->setiv(ssh->sc_cipher_ctx, keyspace);
4343 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'E',keyspace);
4344 ssh->csmac->setkey(ssh->cs_mac_ctx, keyspace);
4345 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'F',keyspace);
4346 ssh->scmac->setkey(ssh->sc_mac_ctx, keyspace);
4347 }
4348 logeventf(ssh, "Initialised %.200s client->server encryption",
4349 ssh->cscipher->text_name);
4350 logeventf(ssh, "Initialised %.200s server->client encryption",
4351 ssh->sccipher->text_name);
4352 if (ssh->cscomp->text_name)
4353 logeventf(ssh, "Initialised %s compression",
4354 ssh->cscomp->text_name);
4355 if (ssh->sccomp->text_name)
4356 logeventf(ssh, "Initialised %s decompression",
4357 ssh->sccomp->text_name);
4358 freebn(s->f);
4359 freebn(s->g);
4360 freebn(s->K);
4361 freebn(s->p);
4362
4363 /*
4364 * If this is the first key exchange phase, we must pass the
4365 * SSH2_MSG_NEWKEYS packet to the next layer, not because it
4366 * wants to see it but because it will need time to initialise
4367 * itself before it sees an actual packet. In subsequent key
4368 * exchange phases, we don't pass SSH2_MSG_NEWKEYS on, because
4369 * it would only confuse the layer above.
4370 */
4371 if (!s->first_kex) {
4372 crReturn(0);
4373 }
4374 s->first_kex = 0;
4375
4376 /*
4377 * Now we're encrypting. Begin returning 1 to the protocol main
4378 * function so that other things can run on top of the
4379 * transport. If we ever see a KEXINIT, we must go back to the
4380 * start.
4381 */
4382 while (!(ispkt && ssh->pktin.type == SSH2_MSG_KEXINIT)) {
4383 crReturn(1);
4384 }
4385 logevent("Server initiated key re-exchange");
4386 goto begin_key_exchange;
4387
4388 crFinish(1);
4389 }
4390
4391 /*
4392 * Add data to an SSH2 channel output buffer.
4393 */
4394 static void ssh2_add_channel_data(struct ssh_channel *c, char *buf,
4395 int len)
4396 {
4397 bufchain_add(&c->v.v2.outbuffer, buf, len);
4398 }
4399
4400 /*
4401 * Attempt to send data on an SSH2 channel.
4402 */
4403 static int ssh2_try_send(struct ssh_channel *c)
4404 {
4405 Ssh ssh = c->ssh;
4406
4407 while (c->v.v2.remwindow > 0 && bufchain_size(&c->v.v2.outbuffer) > 0) {
4408 int len;
4409 void *data;
4410 bufchain_prefix(&c->v.v2.outbuffer, &data, &len);
4411 if ((unsigned)len > c->v.v2.remwindow)
4412 len = c->v.v2.remwindow;
4413 if ((unsigned)len > c->v.v2.remmaxpkt)
4414 len = c->v.v2.remmaxpkt;
4415 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_DATA);
4416 ssh2_pkt_adduint32(ssh, c->remoteid);
4417 ssh2_pkt_addstring_start(ssh);
4418 ssh2_pkt_addstring_data(ssh, data, len);
4419 ssh2_pkt_send(ssh);
4420 bufchain_consume(&c->v.v2.outbuffer, len);
4421 c->v.v2.remwindow -= len;
4422 }
4423
4424 /*
4425 * After having sent as much data as we can, return the amount
4426 * still buffered.
4427 */
4428 return bufchain_size(&c->v.v2.outbuffer);
4429 }
4430
4431 /*
4432 * Potentially enlarge the window on an SSH2 channel.
4433 */
4434 static void ssh2_set_window(struct ssh_channel *c, unsigned newwin)
4435 {
4436 Ssh ssh = c->ssh;
4437
4438 /*
4439 * Never send WINDOW_ADJUST for a channel that the remote side
4440 * already thinks it's closed; there's no point, since it won't
4441 * be sending any more data anyway.
4442 */
4443 if (c->closes != 0)
4444 return;
4445
4446 if (newwin > c->v.v2.locwindow) {
4447 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST);
4448 ssh2_pkt_adduint32(ssh, c->remoteid);
4449 ssh2_pkt_adduint32(ssh, newwin - c->v.v2.locwindow);
4450 ssh2_pkt_send(ssh);
4451 c->v.v2.locwindow = newwin;
4452 }
4453 }
4454
4455 /*
4456 * Handle the SSH2 userauth and connection layers.
4457 */
4458 static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
4459 {
4460 struct do_ssh2_authconn_state {
4461 enum {
4462 AUTH_INVALID, AUTH_PUBLICKEY_AGENT, AUTH_PUBLICKEY_FILE,
4463 AUTH_PASSWORD,
4464 AUTH_KEYBOARD_INTERACTIVE
4465 } method;
4466 enum {
4467 AUTH_TYPE_NONE,
4468 AUTH_TYPE_PUBLICKEY,
4469 AUTH_TYPE_PUBLICKEY_OFFER_LOUD,
4470 AUTH_TYPE_PUBLICKEY_OFFER_QUIET,
4471 AUTH_TYPE_PASSWORD,
4472 AUTH_TYPE_KEYBOARD_INTERACTIVE,
4473 AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET
4474 } type;
4475 int gotit, need_pw, can_pubkey, can_passwd, can_keyb_inter;
4476 int tried_pubkey_config, tried_agent, tried_keyb_inter;
4477 int kbd_inter_running;
4478 int we_are_in;
4479 int num_prompts, curr_prompt, echo;
4480 char username[100];
4481 int got_username;
4482 char pwprompt[200];
4483 char password[100];
4484 void *publickey_blob;
4485 int publickey_bloblen;
4486 unsigned char request[5], *response, *p;
4487 int responselen;
4488 int keyi, nkeys;
4489 int authed;
4490 char *pkblob, *alg, *commentp;
4491 int pklen, alglen, commentlen;
4492 int siglen, retlen, len;
4493 char *q, *agentreq, *ret;
4494 int try_send;
4495 };
4496 crState(do_ssh2_authconn_state);
4497
4498 crBegin(ssh->do_ssh2_authconn_crstate);
4499
4500 /*
4501 * Request userauth protocol, and await a response to it.
4502 */
4503 ssh2_pkt_init(ssh, SSH2_MSG_SERVICE_REQUEST);
4504 ssh2_pkt_addstring(ssh, "ssh-userauth");
4505 ssh2_pkt_send(ssh);
4506 crWaitUntilV(ispkt);
4507 if (ssh->pktin.type != SSH2_MSG_SERVICE_ACCEPT) {
4508 bombout(("Server refused user authentication protocol"));
4509 crStopV;
4510 }
4511
4512 /*
4513 * We repeat this whole loop, including the username prompt,
4514 * until we manage a successful authentication. If the user
4515 * types the wrong _password_, they can be sent back to the
4516 * beginning to try another username, if this is configured on.
4517 * (If they specify a username in the config, they are never
4518 * asked, even if they do give a wrong password.)
4519 *
4520 * I think this best serves the needs of
4521 *
4522 * - the people who have no configuration, no keys, and just
4523 * want to try repeated (username,password) pairs until they
4524 * type both correctly
4525 *
4526 * - people who have keys and configuration but occasionally
4527 * need to fall back to passwords
4528 *
4529 * - people with a key held in Pageant, who might not have
4530 * logged in to a particular machine before; so they want to
4531 * type a username, and then _either_ their key will be
4532 * accepted, _or_ they will type a password. If they mistype
4533 * the username they will want to be able to get back and
4534 * retype it!
4535 */
4536 s->username[0] = '\0';
4537 s->got_username = FALSE;
4538 do {
4539 /*
4540 * Get a username.
4541 */
4542 if (s->got_username && !ssh->cfg.change_username) {
4543 /*
4544 * We got a username last time round this loop, and
4545 * with change_username turned off we don't try to get
4546 * it again.
4547 */
4548 } else if ((flags & FLAG_INTERACTIVE) && !*ssh->cfg.username) {
4549 if (ssh_get_line && !ssh_getline_pw_only) {
4550 if (!ssh_get_line("login as: ",
4551 s->username, sizeof(s->username), FALSE)) {
4552 /*
4553 * get_line failed to get a username.
4554 * Terminate.
4555 */
4556 logevent("No username provided. Abandoning session.");
4557 ssh_closing((Plug)ssh, NULL, 0, 0);
4558 crStopV;
4559 }
4560 } else {
4561 int ret; /* need not be saved across crReturn */
4562 c_write_str(ssh, "login as: ");
4563 ssh->send_ok = 1;
4564 setup_userpass_input(ssh, s->username, sizeof(s->username), 1);
4565 do {
4566 crWaitUntilV(!ispkt);
4567 ret = process_userpass_input(ssh, in, inlen);
4568 } while (ret == 0);
4569 if (ret < 0)
4570 cleanup_exit(0);
4571 c_write_str(ssh, "\r\n");
4572 }
4573 s->username[strcspn(s->username, "\n\r")] = '\0';
4574 } else {
4575 char *stuff;
4576 strncpy(s->username, ssh->cfg.username, sizeof(s->username));
4577 s->username[sizeof(s->username)-1] = '\0';
4578 if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
4579 stuff = dupprintf("Using username \"%s\".\r\n", s->username);
4580 c_write_str(ssh, stuff);
4581 sfree(stuff);
4582 }
4583 }
4584 s->got_username = TRUE;
4585
4586 /*
4587 * Send an authentication request using method "none": (a)
4588 * just in case it succeeds, and (b) so that we know what
4589 * authentication methods we can usefully try next.
4590 */
4591 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4592
4593 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4594 ssh2_pkt_addstring(ssh, s->username);
4595 ssh2_pkt_addstring(ssh, "ssh-connection");/* service requested */
4596 ssh2_pkt_addstring(ssh, "none"); /* method */
4597 ssh2_pkt_send(ssh);
4598 s->type = AUTH_TYPE_NONE;
4599 s->gotit = FALSE;
4600 s->we_are_in = FALSE;
4601
4602 s->tried_pubkey_config = FALSE;
4603 s->tried_agent = FALSE;
4604 s->tried_keyb_inter = FALSE;
4605 s->kbd_inter_running = FALSE;
4606 /* Load the pub half of ssh->cfg.keyfile so we notice if it's in Pageant */
4607 if (!filename_is_null(ssh->cfg.keyfile)) {
4608 int keytype;
4609 logeventf(ssh, "Reading private key file \"%.150s\"",
4610 filename_to_str(&ssh->cfg.keyfile));
4611 keytype = key_type(&ssh->cfg.keyfile);
4612 if (keytype == SSH_KEYTYPE_SSH2) {
4613 s->publickey_blob =
4614 ssh2_userkey_loadpub(&ssh->cfg.keyfile, NULL,
4615 &s->publickey_bloblen, NULL);
4616 } else {
4617 char *msgbuf;
4618 logeventf(ssh, "Unable to use this key file (%s)",
4619 key_type_to_str(keytype));
4620 msgbuf = dupprintf("Unable to use key file \"%.150s\""
4621 " (%s)\r\n",
4622 filename_to_str(&ssh->cfg.keyfile),
4623 key_type_to_str(keytype));
4624 c_write_str(ssh, msgbuf);
4625 sfree(msgbuf);
4626 s->publickey_blob = NULL;
4627 }
4628 } else
4629 s->publickey_blob = NULL;
4630
4631 while (1) {
4632 /*
4633 * Wait for the result of the last authentication request.
4634 */
4635 if (!s->gotit)
4636 crWaitUntilV(ispkt);
4637 while (ssh->pktin.type == SSH2_MSG_USERAUTH_BANNER) {
4638 char *banner;
4639 int size;
4640 /*
4641 * Don't show the banner if we're operating in
4642 * non-verbose non-interactive mode. (It's probably
4643 * a script, which means nobody will read the
4644 * banner _anyway_, and moreover the printing of
4645 * the banner will screw up processing on the
4646 * output of (say) plink.)
4647 */
4648 if (flags & (FLAG_VERBOSE | FLAG_INTERACTIVE)) {
4649 ssh2_pkt_getstring(ssh, &banner, &size);
4650 if (banner)
4651 c_write_untrusted(ssh, banner, size);
4652 }
4653 crWaitUntilV(ispkt);
4654 }
4655 if (ssh->pktin.type == SSH2_MSG_USERAUTH_SUCCESS) {
4656 logevent("Access granted");
4657 s->we_are_in = TRUE;
4658 break;
4659 }
4660
4661 if (s->kbd_inter_running &&
4662 ssh->pktin.type == SSH2_MSG_USERAUTH_INFO_REQUEST) {
4663 /*
4664 * This is either a further set-of-prompts packet
4665 * in keyboard-interactive authentication, or it's
4666 * the same one and we came back here with `gotit'
4667 * set. In the former case, we must reset the
4668 * curr_prompt variable.
4669 */
4670 if (!s->gotit)
4671 s->curr_prompt = 0;
4672 } else if (ssh->pktin.type != SSH2_MSG_USERAUTH_FAILURE) {
4673 bombout(("Strange packet received during authentication: type %d",
4674 ssh->pktin.type));
4675 crStopV;
4676 }
4677
4678 s->gotit = FALSE;
4679
4680 /*
4681 * OK, we're now sitting on a USERAUTH_FAILURE message, so
4682 * we can look at the string in it and know what we can
4683 * helpfully try next.
4684 */
4685 if (ssh->pktin.type == SSH2_MSG_USERAUTH_FAILURE) {
4686 char *methods;
4687 int methlen;
4688 ssh2_pkt_getstring(ssh, &methods, &methlen);
4689 s->kbd_inter_running = FALSE;
4690 if (!ssh2_pkt_getbool(ssh)) {
4691 /*
4692 * We have received an unequivocal Access
4693 * Denied. This can translate to a variety of
4694 * messages:
4695 *
4696 * - if we'd just tried "none" authentication,
4697 * it's not worth printing anything at all
4698 *
4699 * - if we'd just tried a public key _offer_,
4700 * the message should be "Server refused our
4701 * key" (or no message at all if the key
4702 * came from Pageant)
4703 *
4704 * - if we'd just tried anything else, the
4705 * message really should be "Access denied".
4706 *
4707 * Additionally, if we'd just tried password
4708 * authentication, we should break out of this
4709 * whole loop so as to go back to the username
4710 * prompt.
4711 */
4712 if (s->type == AUTH_TYPE_NONE) {
4713 /* do nothing */
4714 } else if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD ||
4715 s->type == AUTH_TYPE_PUBLICKEY_OFFER_QUIET) {
4716 if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD)
4717 c_write_str(ssh, "Server refused our key\r\n");
4718 logevent("Server refused public key");
4719 } else if (s->type==AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET) {
4720 /* server declined keyboard-interactive; ignore */
4721 } else {
4722 c_write_str(ssh, "Access denied\r\n");
4723 logevent("Access denied");
4724 if (s->type == AUTH_TYPE_PASSWORD) {
4725 s->we_are_in = FALSE;
4726 break;
4727 }
4728 }
4729 } else {
4730 c_write_str(ssh, "Further authentication required\r\n");
4731 logevent("Further authentication required");
4732 }
4733
4734 s->can_pubkey =
4735 in_commasep_string("publickey", methods, methlen);
4736 s->can_passwd =
4737 in_commasep_string("password", methods, methlen);
4738 s->can_keyb_inter = ssh->cfg.try_ki_auth &&
4739 in_commasep_string("keyboard-interactive", methods, methlen);
4740 }
4741
4742 s->method = 0;
4743 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4744
4745 /*
4746 * Most password/passphrase prompts will be
4747 * non-echoing, so we set this to 0 by default.
4748 * Exception is that some keyboard-interactive prompts
4749 * can be echoing, in which case we'll set this to 1.
4750 */
4751 s->echo = 0;
4752
4753 if (!s->method && s->can_pubkey &&
4754 agent_exists() && !s->tried_agent) {
4755 /*
4756 * Attempt public-key authentication using Pageant.
4757 */
4758 void *r;
4759 s->authed = FALSE;
4760
4761 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4762 ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
4763
4764 s->tried_agent = TRUE;
4765
4766 logevent("Pageant is running. Requesting keys.");
4767
4768 /* Request the keys held by the agent. */
4769 PUT_32BIT(s->request, 1);
4770 s->request[4] = SSH2_AGENTC_REQUEST_IDENTITIES;
4771 if (!agent_query(s->request, 5, &r, &s->responselen,
4772 ssh_agent_callback, ssh)) {
4773 do {
4774 crReturnV;
4775 if (ispkt) {
4776 bombout(("Unexpected data from server while"
4777 " waiting for agent response"));
4778 crStopV;
4779 }
4780 } while (ispkt || inlen > 0);
4781 r = ssh->agent_response;
4782 s->responselen = ssh->agent_response_len;
4783 }
4784 s->response = (unsigned char *) r;
4785 if (s->response && s->responselen >= 5 &&
4786 s->response[4] == SSH2_AGENT_IDENTITIES_ANSWER) {
4787 s->p = s->response + 5;
4788 s->nkeys = GET_32BIT(s->p);
4789 s->p += 4;
4790 {
4791 char buf[64];
4792 sprintf(buf, "Pageant has %d SSH2 keys", s->nkeys);
4793 logevent(buf);
4794 }
4795 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
4796 void *vret;
4797
4798 {
4799 char buf[64];
4800 sprintf(buf, "Trying Pageant key #%d", s->keyi);
4801 logevent(buf);
4802 }
4803 s->pklen = GET_32BIT(s->p);
4804 s->p += 4;
4805 if (s->publickey_blob &&
4806 s->pklen == s->publickey_bloblen &&
4807 !memcmp(s->p, s->publickey_blob,
4808 s->publickey_bloblen)) {
4809 logevent("This key matches configured key file");
4810 s->tried_pubkey_config = 1;
4811 }
4812 s->pkblob = (char *)s->p;
4813 s->p += s->pklen;
4814 s->alglen = GET_32BIT(s->pkblob);
4815 s->alg = s->pkblob + 4;
4816 s->commentlen = GET_32BIT(s->p);
4817 s->p += 4;
4818 s->commentp = (char *)s->p;
4819 s->p += s->commentlen;
4820 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4821 ssh2_pkt_addstring(ssh, s->username);
4822 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4823 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4824 ssh2_pkt_addbool(ssh, FALSE); /* no signature included */
4825 ssh2_pkt_addstring_start(ssh);
4826 ssh2_pkt_addstring_data(ssh, s->alg, s->alglen);
4827 ssh2_pkt_addstring_start(ssh);
4828 ssh2_pkt_addstring_data(ssh, s->pkblob, s->pklen);
4829 ssh2_pkt_send(ssh);
4830
4831 crWaitUntilV(ispkt);
4832 if (ssh->pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
4833 logevent("Key refused");
4834 continue;
4835 }
4836
4837 if (flags & FLAG_VERBOSE) {
4838 c_write_str(ssh, "Authenticating with "
4839 "public key \"");
4840 c_write(ssh, s->commentp, s->commentlen);
4841 c_write_str(ssh, "\" from agent\r\n");
4842 }
4843
4844 /*
4845 * Server is willing to accept the key.
4846 * Construct a SIGN_REQUEST.
4847 */
4848 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4849 ssh2_pkt_addstring(ssh, s->username);
4850 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4851 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4852 ssh2_pkt_addbool(ssh, TRUE);
4853 ssh2_pkt_addstring_start(ssh);
4854 ssh2_pkt_addstring_data(ssh, s->alg, s->alglen);
4855 ssh2_pkt_addstring_start(ssh);
4856 ssh2_pkt_addstring_data(ssh, s->pkblob, s->pklen);
4857
4858 s->siglen = ssh->pktout.length - 5 + 4 + 20;
4859 if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
4860 s->siglen -= 4;
4861 s->len = 1; /* message type */
4862 s->len += 4 + s->pklen; /* key blob */
4863 s->len += 4 + s->siglen; /* data to sign */
4864 s->len += 4; /* flags */
4865 s->agentreq = snewn(4 + s->len, char);
4866 PUT_32BIT(s->agentreq, s->len);
4867 s->q = s->agentreq + 4;
4868 *s->q++ = SSH2_AGENTC_SIGN_REQUEST;
4869 PUT_32BIT(s->q, s->pklen);
4870 s->q += 4;
4871 memcpy(s->q, s->pkblob, s->pklen);
4872 s->q += s->pklen;
4873 PUT_32BIT(s->q, s->siglen);
4874 s->q += 4;
4875 /* Now the data to be signed... */
4876 if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
4877 PUT_32BIT(s->q, 20);
4878 s->q += 4;
4879 }
4880 memcpy(s->q, ssh->v2_session_id, 20);
4881 s->q += 20;
4882 memcpy(s->q, ssh->pktout.data + 5,
4883 ssh->pktout.length - 5);
4884 s->q += ssh->pktout.length - 5;
4885 /* And finally the (zero) flags word. */
4886 PUT_32BIT(s->q, 0);
4887 if (!agent_query(s->agentreq, s->len + 4,
4888 &vret, &s->retlen,
4889 ssh_agent_callback, ssh)) {
4890 do {
4891 crReturnV;
4892 if (ispkt) {
4893 bombout(("Unexpected data from server"
4894 " while waiting for agent"
4895 " response"));
4896 crStopV;
4897 }
4898 } while (ispkt || inlen > 0);
4899 vret = ssh->agent_response;
4900 s->retlen = ssh->agent_response_len;
4901 }
4902 s->ret = vret;
4903 sfree(s->agentreq);
4904 if (s->ret) {
4905 if (s->ret[4] == SSH2_AGENT_SIGN_RESPONSE) {
4906 logevent("Sending Pageant's response");
4907 ssh2_add_sigblob(ssh, s->pkblob, s->pklen,
4908 s->ret + 9,
4909 GET_32BIT(s->ret + 5));
4910 ssh2_pkt_send(ssh);
4911 s->authed = TRUE;
4912 break;
4913 } else {
4914 logevent
4915 ("Pageant failed to answer challenge");
4916 sfree(s->ret);
4917 }
4918 }
4919 }
4920 if (s->authed)
4921 continue;
4922 }
4923 }
4924
4925 if (!s->method && s->can_pubkey && s->publickey_blob
4926 && !s->tried_pubkey_config) {
4927 unsigned char *pub_blob;
4928 char *algorithm, *comment;
4929 int pub_blob_len;
4930
4931 s->tried_pubkey_config = TRUE;
4932
4933 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4934 ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
4935
4936 /*
4937 * Try the public key supplied in the configuration.
4938 *
4939 * First, offer the public blob to see if the server is
4940 * willing to accept it.
4941 */
4942 pub_blob =
4943 (unsigned char *)ssh2_userkey_loadpub(&ssh->cfg.keyfile,
4944 &algorithm,
4945 &pub_blob_len,
4946 NULL);
4947 if (pub_blob) {
4948 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4949 ssh2_pkt_addstring(ssh, s->username);
4950 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4951 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4952 ssh2_pkt_addbool(ssh, FALSE); /* no signature included */
4953 ssh2_pkt_addstring(ssh, algorithm);
4954 ssh2_pkt_addstring_start(ssh);
4955 ssh2_pkt_addstring_data(ssh, (char *)pub_blob,
4956 pub_blob_len);
4957 ssh2_pkt_send(ssh);
4958 logevent("Offered public key"); /* FIXME */
4959
4960 crWaitUntilV(ispkt);
4961 if (ssh->pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
4962 s->gotit = TRUE;
4963 s->type = AUTH_TYPE_PUBLICKEY_OFFER_LOUD;
4964 continue; /* key refused; give up on it */
4965 }
4966
4967 logevent("Offer of public key accepted");
4968 /*
4969 * Actually attempt a serious authentication using
4970 * the key.
4971 */
4972 if (ssh2_userkey_encrypted(&ssh->cfg.keyfile, &comment)) {
4973 sprintf(s->pwprompt,
4974 "Passphrase for key \"%.100s\": ",
4975 comment);
4976 s->need_pw = TRUE;
4977 } else {
4978 s->need_pw = FALSE;
4979 }
4980 c_write_str(ssh, "Authenticating with public key \"");
4981 c_write_str(ssh, comment);
4982 c_write_str(ssh, "\"\r\n");
4983 s->method = AUTH_PUBLICKEY_FILE;
4984 }
4985 }
4986
4987 if (!s->method && s->can_keyb_inter && !s->tried_keyb_inter) {
4988 s->method = AUTH_KEYBOARD_INTERACTIVE;
4989 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
4990 s->tried_keyb_inter = TRUE;
4991
4992 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4993 ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;
4994
4995 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4996 ssh2_pkt_addstring(ssh, s->username);
4997 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4998 ssh2_pkt_addstring(ssh, "keyboard-interactive"); /* method */
4999 ssh2_pkt_addstring(ssh, ""); /* lang */
5000 ssh2_pkt_addstring(ssh, "");
5001 ssh2_pkt_send(ssh);
5002
5003 crWaitUntilV(ispkt);
5004 if (ssh->pktin.type != SSH2_MSG_USERAUTH_INFO_REQUEST) {
5005 if (ssh->pktin.type == SSH2_MSG_USERAUTH_FAILURE)
5006 s->gotit = TRUE;
5007 logevent("Keyboard-interactive authentication refused");
5008 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET;
5009 continue;
5010 }
5011
5012 s->kbd_inter_running = TRUE;
5013 s->curr_prompt = 0;
5014 }
5015
5016 if (s->kbd_inter_running) {
5017 s->method = AUTH_KEYBOARD_INTERACTIVE;
5018 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
5019 s->tried_keyb_inter = TRUE;
5020
5021 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
5022 ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;
5023
5024 if (s->curr_prompt == 0) {
5025 /*
5026 * We've got a fresh USERAUTH_INFO_REQUEST.
5027 * Display header data, and start going through
5028 * the prompts.
5029 */
5030 char *name, *inst, *lang;
5031 int name_len, inst_len, lang_len;
5032
5033 ssh2_pkt_getstring(ssh, &name, &name_len);
5034 ssh2_pkt_getstring(ssh, &inst, &inst_len);
5035 ssh2_pkt_getstring(ssh, &lang, &lang_len);
5036 if (name_len > 0) {
5037 c_write_untrusted(ssh, name, name_len);
5038 c_write_str(ssh, "\r\n");
5039 }
5040 if (inst_len > 0) {
5041 c_write_untrusted(ssh, inst, inst_len);
5042 c_write_str(ssh, "\r\n");
5043 }
5044 s->num_prompts = ssh2_pkt_getuint32(ssh);
5045 }
5046
5047 /*
5048 * If there are prompts remaining in the packet,
5049 * display one and get a response.
5050 */
5051 if (s->curr_prompt < s->num_prompts) {
5052 char *prompt;
5053 int prompt_len;
5054
5055 ssh2_pkt_getstring(ssh, &prompt, &prompt_len);
5056 if (prompt_len > 0) {
5057 strncpy(s->pwprompt, prompt, sizeof(s->pwprompt));
5058 s->pwprompt[prompt_len < sizeof(s->pwprompt) ?
5059 prompt_len : sizeof(s->pwprompt)-1] = '\0';
5060 } else {
5061 strcpy(s->pwprompt,
5062 "<server failed to send prompt>: ");
5063 }
5064 s->echo = ssh2_pkt_getbool(ssh);
5065 s->need_pw = TRUE;
5066 } else
5067 s->need_pw = FALSE;
5068 }
5069
5070 if (!s->method && s->can_passwd) {
5071 s->method = AUTH_PASSWORD;
5072 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
5073 ssh->pkt_ctx |= SSH2_PKTCTX_PASSWORD;
5074 sprintf(s->pwprompt, "%.90s@%.90s's password: ", s->username,
5075 ssh->savedhost);
5076 s->need_pw = TRUE;
5077 }
5078
5079 if (s->need_pw) {
5080 if (ssh_get_line) {
5081 if (!ssh_get_line(s->pwprompt, s->password,
5082 sizeof(s->password), TRUE)) {
5083 /*
5084 * get_line failed to get a password (for
5085 * example because one was supplied on the
5086 * command line which has already failed to
5087 * work). Terminate.
5088 */
5089 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5090 ssh2_pkt_adduint32(ssh,SSH2_DISCONNECT_BY_APPLICATION);
5091 ssh2_pkt_addstring(ssh, "No more passwords available"
5092 " to try");
5093 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5094 ssh2_pkt_send(ssh);
5095 logevent("Unable to authenticate");
5096 connection_fatal(ssh->frontend,
5097 "Unable to authenticate");
5098 ssh_closing((Plug)ssh, NULL, 0, 0);
5099 crStopV;
5100 }
5101 } else {
5102 int ret; /* need not be saved across crReturn */
5103 c_write_untrusted(ssh, s->pwprompt, strlen(s->pwprompt));
5104 ssh->send_ok = 1;
5105
5106 setup_userpass_input(ssh, s->password,
5107 sizeof(s->password), s->echo);
5108 do {
5109 crWaitUntilV(!ispkt);
5110 ret = process_userpass_input(ssh, in, inlen);
5111 } while (ret == 0);
5112 if (ret < 0)
5113 cleanup_exit(0);
5114 c_write_str(ssh, "\r\n");
5115 }
5116 }
5117
5118 if (s->method == AUTH_PUBLICKEY_FILE) {
5119 /*
5120 * We have our passphrase. Now try the actual authentication.
5121 */
5122 struct ssh2_userkey *key;
5123 const char *error = NULL;
5124
5125 key = ssh2_load_userkey(&ssh->cfg.keyfile, s->password,
5126 &error);
5127 if (key == SSH2_WRONG_PASSPHRASE || key == NULL) {
5128 if (key == SSH2_WRONG_PASSPHRASE) {
5129 c_write_str(ssh, "Wrong passphrase\r\n");
5130 s->tried_pubkey_config = FALSE;
5131 } else {
5132 c_write_str(ssh, "Unable to load private key (");
5133 c_write_str(ssh, error);
5134 c_write_str(ssh, ")\r\n");
5135 s->tried_pubkey_config = TRUE;
5136 }
5137 /* Send a spurious AUTH_NONE to return to the top. */
5138 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
5139 ssh2_pkt_addstring(ssh, s->username);
5140 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
5141 ssh2_pkt_addstring(ssh, "none"); /* method */
5142 ssh2_pkt_send(ssh);
5143 s->type = AUTH_TYPE_NONE;
5144 } else {
5145 unsigned char *pkblob, *sigblob, *sigdata;
5146 int pkblob_len, sigblob_len, sigdata_len;
5147 int p;
5148
5149 /*
5150 * We have loaded the private key and the server
5151 * has announced that it's willing to accept it.
5152 * Hallelujah. Generate a signature and send it.
5153 */
5154 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
5155 ssh2_pkt_addstring(ssh, s->username);
5156 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
5157 ssh2_pkt_addstring(ssh, "publickey"); /* method */
5158 ssh2_pkt_addbool(ssh, TRUE);
5159 ssh2_pkt_addstring(ssh, key->alg->name);
5160 pkblob = key->alg->public_blob(key->data, &pkblob_len);
5161 ssh2_pkt_addstring_start(ssh);
5162 ssh2_pkt_addstring_data(ssh, (char *)pkblob, pkblob_len);
5163
5164 /*
5165 * The data to be signed is:
5166 *
5167 * string session-id
5168 *
5169 * followed by everything so far placed in the
5170 * outgoing packet.
5171 */
5172 sigdata_len = ssh->pktout.length - 5 + 4 + 20;
5173 if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
5174 sigdata_len -= 4;
5175 sigdata = snewn(sigdata_len, unsigned char);
5176 p = 0;
5177 if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
5178 PUT_32BIT(sigdata+p, 20);
5179 p += 4;
5180 }
5181 memcpy(sigdata+p, ssh->v2_session_id, 20); p += 20;
5182 memcpy(sigdata+p, ssh->pktout.data + 5,
5183 ssh->pktout.length - 5);
5184 p += ssh->pktout.length - 5;
5185 assert(p == sigdata_len);
5186 sigblob = key->alg->sign(key->data, (char *)sigdata,
5187 sigdata_len, &sigblob_len);
5188 ssh2_add_sigblob(ssh, pkblob, pkblob_len,
5189 sigblob, sigblob_len);
5190 sfree(pkblob);
5191 sfree(sigblob);
5192 sfree(sigdata);
5193
5194 ssh2_pkt_send(ssh);
5195 s->type = AUTH_TYPE_PUBLICKEY;
5196 }
5197 } else if (s->method == AUTH_PASSWORD) {
5198 /*
5199 * We send the password packet lumped tightly together with
5200 * an SSH_MSG_IGNORE packet. The IGNORE packet contains a
5201 * string long enough to make the total length of the two
5202 * packets constant. This should ensure that a passive
5203 * listener doing traffic analyis can't work out the length
5204 * of the password.
5205 *
5206 * For this to work, we need an assumption about the
5207 * maximum length of the password packet. I think 256 is
5208 * pretty conservative. Anyone using a password longer than
5209 * that probably doesn't have much to worry about from
5210 * people who find out how long their password is!
5211 */
5212 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
5213 ssh2_pkt_addstring(ssh, s->username);
5214 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
5215 ssh2_pkt_addstring(ssh, "password");
5216 ssh2_pkt_addbool(ssh, FALSE);
5217 ssh2_pkt_addstring(ssh, s->password);
5218 memset(s->password, 0, sizeof(s->password));
5219 ssh2_pkt_defer(ssh);
5220 /*
5221 * We'll include a string that's an exact multiple of the
5222 * cipher block size. If the cipher is NULL for some
5223 * reason, we don't do this trick at all because we gain
5224 * nothing by it.
5225 */
5226 if (ssh->cscipher) {
5227 int stringlen, i;
5228
5229 stringlen = (256 - ssh->deferred_len);
5230 stringlen += ssh->cscipher->blksize - 1;
5231 stringlen -= (stringlen % ssh->cscipher->blksize);
5232 if (ssh->cscomp) {
5233 /*
5234 * Temporarily disable actual compression,
5235 * so we can guarantee to get this string
5236 * exactly the length we want it. The
5237 * compression-disabling routine should
5238 * return an integer indicating how many
5239 * bytes we should adjust our string length
5240 * by.
5241 */
5242 stringlen -=
5243 ssh->cscomp->disable_compression(ssh->cs_comp_ctx);
5244 }
5245 ssh2_pkt_init(ssh, SSH2_MSG_IGNORE);
5246 ssh2_pkt_addstring_start(ssh);
5247 for (i = 0; i < stringlen; i++) {
5248 char c = (char) random_byte();
5249 ssh2_pkt_addstring_data(ssh, &c, 1);
5250 }
5251 ssh2_pkt_defer(ssh);
5252 }
5253 ssh_pkt_defersend(ssh);
5254 logevent("Sent password");
5255 s->type = AUTH_TYPE_PASSWORD;
5256 } else if (s->method == AUTH_KEYBOARD_INTERACTIVE) {
5257 if (s->curr_prompt == 0) {
5258 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_INFO_RESPONSE);
5259 ssh2_pkt_adduint32(ssh, s->num_prompts);
5260 }
5261 if (s->need_pw) { /* only add pw if we just got one! */
5262 ssh2_pkt_addstring(ssh, s->password);
5263 memset(s->password, 0, sizeof(s->password));
5264 s->curr_prompt++;
5265 }
5266 if (s->curr_prompt >= s->num_prompts) {
5267 ssh2_pkt_send(ssh);
5268 } else {
5269 /*
5270 * If there are prompts remaining, we set
5271 * `gotit' so that we won't attempt to get
5272 * another packet. Then we go back round the
5273 * loop and will end up retrieving another
5274 * prompt out of the existing packet. Funky or
5275 * what?
5276 */
5277 s->gotit = TRUE;
5278 }
5279 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
5280 } else {
5281 c_write_str(ssh, "No supported authentication methods"
5282 " left to try!\r\n");
5283 logevent("No supported authentications offered."
5284 " Disconnecting");
5285 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5286 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5287 ssh2_pkt_addstring(ssh, "No supported authentication"
5288 " methods available");
5289 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5290 ssh2_pkt_send(ssh);
5291 ssh_closing((Plug)ssh, NULL, 0, 0);
5292 crStopV;
5293 }
5294 }
5295 } while (!s->we_are_in);
5296
5297 /*
5298 * Now we're authenticated for the connection protocol. The
5299 * connection protocol will automatically have started at this
5300 * point; there's no need to send SERVICE_REQUEST.
5301 */
5302
5303 /*
5304 * So now create a channel with a session in it.
5305 */
5306 ssh->channels = newtree234(ssh_channelcmp);
5307 ssh->mainchan = snew(struct ssh_channel);
5308 ssh->mainchan->ssh = ssh;
5309 ssh->mainchan->localid = alloc_channel_id(ssh);
5310 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN);
5311 ssh2_pkt_addstring(ssh, "session");
5312 ssh2_pkt_adduint32(ssh, ssh->mainchan->localid);
5313 ssh->mainchan->v.v2.locwindow = OUR_V2_WINSIZE;
5314 ssh2_pkt_adduint32(ssh, ssh->mainchan->v.v2.locwindow);/* our window size */
5315 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
5316 ssh2_pkt_send(ssh);
5317 crWaitUntilV(ispkt);
5318 if (ssh->pktin.type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
5319 bombout(("Server refused to open a session"));
5320 crStopV;
5321 /* FIXME: error data comes back in FAILURE packet */
5322 }
5323 if (ssh2_pkt_getuint32(ssh) != ssh->mainchan->localid) {
5324 bombout(("Server's channel confirmation cited wrong channel"));
5325 crStopV;
5326 }
5327 ssh->mainchan->remoteid = ssh2_pkt_getuint32(ssh);
5328 ssh->mainchan->type = CHAN_MAINSESSION;
5329 ssh->mainchan->closes = 0;
5330 ssh->mainchan->v.v2.remwindow = ssh2_pkt_getuint32(ssh);
5331 ssh->mainchan->v.v2.remmaxpkt = ssh2_pkt_getuint32(ssh);
5332 bufchain_init(&ssh->mainchan->v.v2.outbuffer);
5333 add234(ssh->channels, ssh->mainchan);
5334 logevent("Opened channel for session");
5335
5336 /*
5337 * Potentially enable X11 forwarding.
5338 */
5339 if (ssh->cfg.x11_forward) {
5340 char proto[20], data[64];
5341 logevent("Requesting X11 forwarding");
5342 ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
5343 data, sizeof(data), ssh->cfg.x11_auth);
5344 x11_get_real_auth(ssh->x11auth, ssh->cfg.x11_display);
5345 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5346 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
5347 ssh2_pkt_addstring(ssh, "x11-req");
5348 ssh2_pkt_addbool(ssh, 1); /* want reply */
5349 ssh2_pkt_addbool(ssh, 0); /* many connections */
5350 ssh2_pkt_addstring(ssh, proto);
5351 ssh2_pkt_addstring(ssh, data);
5352 ssh2_pkt_adduint32(ssh, x11_get_screen_number(ssh->cfg.x11_display));
5353 ssh2_pkt_send(ssh);
5354
5355 do {
5356 crWaitUntilV(ispkt);
5357 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5358 unsigned i = ssh2_pkt_getuint32(ssh);
5359 struct ssh_channel *c;
5360 c = find234(ssh->channels, &i, ssh_channelfind);
5361 if (!c)
5362 continue; /* nonexistent channel */
5363 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5364 }
5365 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5366
5367 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5368 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5369 bombout(("Unexpected response to X11 forwarding request:"
5370 " packet type %d", ssh->pktin.type));
5371 crStopV;
5372 }
5373 logevent("X11 forwarding refused");
5374 } else {
5375 logevent("X11 forwarding enabled");
5376 ssh->X11_fwd_enabled = TRUE;
5377 }
5378 }
5379
5380 /*
5381 * Enable port forwardings.
5382 */
5383 {
5384 char type;
5385 int n;
5386 int sport,dport,sserv,dserv;
5387 char sports[256], dports[256], saddr[256], host[256];
5388
5389 ssh->rportfwds = newtree234(ssh_rportcmp_ssh2);
5390 /* Add port forwardings. */
5391 ssh->portfwd_strptr = ssh->cfg.portfwd;
5392 while (*ssh->portfwd_strptr) {
5393 type = *ssh->portfwd_strptr++;
5394 saddr[0] = '\0';
5395 n = 0;
5396 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != '\t') {
5397 if (*ssh->portfwd_strptr == ':') {
5398 /*
5399 * We've seen a colon in the middle of the
5400 * source port number. This means that
5401 * everything we've seen until now is the
5402 * source _address_, so we'll move it into
5403 * saddr and start sports from the beginning
5404 * again.
5405 */
5406 ssh->portfwd_strptr++;
5407 sports[n] = '\0';
5408 strcpy(saddr, sports);
5409 n = 0;
5410 }
5411 if (n < 255) sports[n++] = *ssh->portfwd_strptr++;
5412 }
5413 sports[n] = 0;
5414 if (type != 'D') {
5415 if (*ssh->portfwd_strptr == '\t')
5416 ssh->portfwd_strptr++;
5417 n = 0;
5418 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':') {
5419 if (n < 255) host[n++] = *ssh->portfwd_strptr++;
5420 }
5421 host[n] = 0;
5422 if (*ssh->portfwd_strptr == ':')
5423 ssh->portfwd_strptr++;
5424 n = 0;
5425 while (*ssh->portfwd_strptr) {
5426 if (n < 255) dports[n++] = *ssh->portfwd_strptr++;
5427 }
5428 dports[n] = 0;
5429 ssh->portfwd_strptr++;
5430 dport = atoi(dports);
5431 dserv = 0;
5432 if (dport == 0) {
5433 dserv = 1;
5434 dport = net_service_lookup(dports);
5435 if (!dport) {
5436 logeventf(ssh, "Service lookup failed for destination"
5437 " port \"%s\"", dports);
5438 }
5439 }
5440 } else {
5441 while (*ssh->portfwd_strptr) ssh->portfwd_strptr++;
5442 dport = dserv = -1;
5443 ssh->portfwd_strptr++; /* eat the NUL and move to next one */
5444 }
5445 sport = atoi(sports);
5446 sserv = 0;
5447 if (sport == 0) {
5448 sserv = 1;
5449 sport = net_service_lookup(sports);
5450 if (!sport) {
5451 logeventf(ssh, "Service lookup failed for source"
5452 " port \"%s\"", sports);
5453 }
5454 }
5455 if (sport && dport) {
5456 if (type == 'L') {
5457 pfd_addforward(host, dport, *saddr ? saddr : NULL,
5458 sport, ssh, &ssh->cfg);
5459 logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
5460 " forwarding to %s:%.*s%.*s%d%.*s",
5461 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
5462 (int)(*saddr?1:0), ":",
5463 (int)(sserv ? strlen(sports) : 0), sports,
5464 sserv, "(", sport, sserv, ")",
5465 host,
5466 (int)(dserv ? strlen(dports) : 0), dports,
5467 dserv, "(", dport, dserv, ")");
5468 } else if (type == 'D') {
5469 pfd_addforward(NULL, -1, *saddr ? saddr : NULL,
5470 sport, ssh, &ssh->cfg);
5471 logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
5472 " doing SOCKS dynamic forwarding",
5473 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
5474 (int)(*saddr?1:0), ":",
5475 (int)(sserv ? strlen(sports) : 0), sports,
5476 sserv, "(", sport, sserv, ")");
5477 } else {
5478 struct ssh_rportfwd *pf;
5479 pf = snew(struct ssh_rportfwd);
5480 strcpy(pf->dhost, host);
5481 pf->dport = dport;
5482 pf->sport = sport;
5483 if (add234(ssh->rportfwds, pf) != pf) {
5484 logeventf(ssh, "Duplicate remote port forwarding"
5485 " to %s:%d", host, dport);
5486 sfree(pf);
5487 } else {
5488 logeventf(ssh, "Requesting remote port "
5489 "%.*s%.*s%.*s%.*s%d%.*s"
5490 " forward to %s:%.*s%.*s%d%.*s",
5491 (int)(*saddr?strlen(saddr):0),
5492 *saddr?saddr:NULL,
5493 (int)(*saddr?1:0), ":",
5494 (int)(sserv ? strlen(sports) : 0), sports,
5495 sserv, "(", sport, sserv, ")",
5496 host,
5497 (int)(dserv ? strlen(dports) : 0), dports,
5498 dserv, "(", dport, dserv, ")");
5499 ssh2_pkt_init(ssh, SSH2_MSG_GLOBAL_REQUEST);
5500 ssh2_pkt_addstring(ssh, "tcpip-forward");
5501 ssh2_pkt_addbool(ssh, 1);/* want reply */
5502 if (*saddr)
5503 ssh2_pkt_addstring(ssh, saddr);
5504 if (ssh->cfg.rport_acceptall)
5505 ssh2_pkt_addstring(ssh, "0.0.0.0");
5506 else
5507 ssh2_pkt_addstring(ssh, "127.0.0.1");
5508 ssh2_pkt_adduint32(ssh, sport);
5509 ssh2_pkt_send(ssh);
5510
5511 do {
5512 crWaitUntilV(ispkt);
5513 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5514 unsigned i = ssh2_pkt_getuint32(ssh);
5515 struct ssh_channel *c;
5516 c = find234(ssh->channels, &i, ssh_channelfind);
5517 if (!c)
5518 continue;/* nonexistent channel */
5519 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5520 }
5521 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5522
5523 if (ssh->pktin.type != SSH2_MSG_REQUEST_SUCCESS) {
5524 if (ssh->pktin.type != SSH2_MSG_REQUEST_FAILURE) {
5525 bombout(("Unexpected response to port "
5526 "forwarding request: packet type %d",
5527 ssh->pktin.type));
5528 crStopV;
5529 }
5530 logevent("Server refused this port forwarding");
5531 } else {
5532 logevent("Remote port forwarding enabled");
5533 }
5534 }
5535 }
5536 }
5537 }
5538 }
5539
5540 /*
5541 * Potentially enable agent forwarding.
5542 */
5543 if (ssh->cfg.agentfwd && agent_exists()) {
5544 logevent("Requesting OpenSSH-style agent forwarding");
5545 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5546 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
5547 ssh2_pkt_addstring(ssh, "auth-agent-req@openssh.com");
5548 ssh2_pkt_addbool(ssh, 1); /* want reply */
5549 ssh2_pkt_send(ssh);
5550
5551 do {
5552 crWaitUntilV(ispkt);
5553 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5554 unsigned i = ssh2_pkt_getuint32(ssh);
5555 struct ssh_channel *c;
5556 c = find234(ssh->channels, &i, ssh_channelfind);
5557 if (!c)
5558 continue; /* nonexistent channel */
5559 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5560 }
5561 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5562
5563 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5564 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5565 bombout(("Unexpected response to agent forwarding request:"
5566 " packet type %d", ssh->pktin.type));
5567 crStopV;
5568 }
5569 logevent("Agent forwarding refused");
5570 } else {
5571 logevent("Agent forwarding enabled");
5572 ssh->agentfwd_enabled = TRUE;
5573 }
5574 }
5575
5576 /*
5577 * Now allocate a pty for the session.
5578 */
5579 if (!ssh->cfg.nopty) {
5580 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5581 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid); /* recipient channel */
5582 ssh2_pkt_addstring(ssh, "pty-req");
5583 ssh2_pkt_addbool(ssh, 1); /* want reply */
5584 ssh2_pkt_addstring(ssh, ssh->cfg.termtype);
5585 ssh2_pkt_adduint32(ssh, ssh->term_width);
5586 ssh2_pkt_adduint32(ssh, ssh->term_height);
5587 ssh2_pkt_adduint32(ssh, 0); /* pixel width */
5588 ssh2_pkt_adduint32(ssh, 0); /* pixel height */
5589 ssh2_pkt_addstring_start(ssh);
5590 ssh2_pkt_addstring_data(ssh, "\0", 1); /* TTY_OP_END, no special options */
5591 ssh2_pkt_send(ssh);
5592 ssh->state = SSH_STATE_INTERMED;
5593
5594 do {
5595 crWaitUntilV(ispkt);
5596 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5597 unsigned i = ssh2_pkt_getuint32(ssh);
5598 struct ssh_channel *c;
5599 c = find234(ssh->channels, &i, ssh_channelfind);
5600 if (!c)
5601 continue; /* nonexistent channel */
5602 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5603 }
5604 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5605
5606 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5607 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5608 bombout(("Unexpected response to pty request:"
5609 " packet type %d", ssh->pktin.type));
5610 crStopV;
5611 }
5612 c_write_str(ssh, "Server refused to allocate pty\r\n");
5613 ssh->editing = ssh->echoing = 1;
5614 } else {
5615 logevent("Allocated pty");
5616 }
5617 } else {
5618 ssh->editing = ssh->echoing = 1;
5619 }
5620
5621 /*
5622 * Start a shell or a remote command. We may have to attempt
5623 * this twice if the config data has provided a second choice
5624 * of command.
5625 */
5626 while (1) {
5627 int subsys;
5628 char *cmd;
5629
5630 if (ssh->fallback_cmd) {
5631 subsys = ssh->cfg.ssh_subsys2;
5632 cmd = ssh->cfg.remote_cmd_ptr2;
5633 } else {
5634 subsys = ssh->cfg.ssh_subsys;
5635 cmd = ssh->cfg.remote_cmd_ptr;
5636 }
5637
5638 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5639 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid); /* recipient channel */
5640 if (subsys) {
5641 ssh2_pkt_addstring(ssh, "subsystem");
5642 ssh2_pkt_addbool(ssh, 1); /* want reply */
5643 ssh2_pkt_addstring(ssh, cmd);
5644 } else if (*cmd) {
5645 ssh2_pkt_addstring(ssh, "exec");
5646 ssh2_pkt_addbool(ssh, 1); /* want reply */
5647 ssh2_pkt_addstring(ssh, cmd);
5648 } else {
5649 ssh2_pkt_addstring(ssh, "shell");
5650 ssh2_pkt_addbool(ssh, 1); /* want reply */
5651 }
5652 ssh2_pkt_send(ssh);
5653 do {
5654 crWaitUntilV(ispkt);
5655 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5656 unsigned i = ssh2_pkt_getuint32(ssh);
5657 struct ssh_channel *c;
5658 c = find234(ssh->channels, &i, ssh_channelfind);
5659 if (!c)
5660 continue; /* nonexistent channel */
5661 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5662 }
5663 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5664 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5665 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5666 bombout(("Unexpected response to shell/command request:"
5667 " packet type %d", ssh->pktin.type));
5668 crStopV;
5669 }
5670 /*
5671 * We failed to start the command. If this is the
5672 * fallback command, we really are finished; if it's
5673 * not, and if the fallback command exists, try falling
5674 * back to it before complaining.
5675 */
5676 if (!ssh->fallback_cmd && ssh->cfg.remote_cmd_ptr2 != NULL) {
5677 logevent("Primary command failed; attempting fallback");
5678 ssh->fallback_cmd = TRUE;
5679 continue;
5680 }
5681 bombout(("Server refused to start a shell/command"));
5682 crStopV;
5683 } else {
5684 logevent("Started a shell/command");
5685 }
5686 break;
5687 }
5688
5689 ssh->state = SSH_STATE_SESSION;
5690 if (ssh->size_needed)
5691 ssh_size(ssh, ssh->term_width, ssh->term_height);
5692 if (ssh->eof_needed)
5693 ssh_special(ssh, TS_EOF);
5694
5695 /*
5696 * Transfer data!
5697 */
5698 if (ssh->ldisc)
5699 ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */
5700 ssh->send_ok = 1;
5701 while (1) {
5702 crReturnV;
5703 s->try_send = FALSE;
5704 if (ispkt) {
5705 if (ssh->pktin.type == SSH2_MSG_CHANNEL_DATA ||
5706 ssh->pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA) {
5707 char *data;
5708 int length;
5709 unsigned i = ssh2_pkt_getuint32(ssh);
5710 struct ssh_channel *c;
5711 c = find234(ssh->channels, &i, ssh_channelfind);
5712 if (!c)
5713 continue; /* nonexistent channel */
5714 if (ssh->pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
5715 ssh2_pkt_getuint32(ssh) != SSH2_EXTENDED_DATA_STDERR)
5716 continue; /* extended but not stderr */
5717 ssh2_pkt_getstring(ssh, &data, &length);
5718 if (data) {
5719 int bufsize = 0;
5720 c->v.v2.locwindow -= length;
5721 switch (c->type) {
5722 case CHAN_MAINSESSION:
5723 bufsize =
5724 from_backend(ssh->frontend, ssh->pktin.type ==
5725 SSH2_MSG_CHANNEL_EXTENDED_DATA,
5726 data, length);
5727 break;
5728 case CHAN_X11:
5729 bufsize = x11_send(c->u.x11.s, data, length);
5730 break;
5731 case CHAN_SOCKDATA:
5732 bufsize = pfd_send(c->u.pfd.s, data, length);
5733 break;
5734 case CHAN_AGENT:
5735 while (length > 0) {
5736 if (c->u.a.lensofar < 4) {
5737 int l = min(4 - c->u.a.lensofar, length);
5738 memcpy(c->u.a.msglen + c->u.a.lensofar,
5739 data, l);
5740 data += l;
5741 length -= l;
5742 c->u.a.lensofar += l;
5743 }
5744 if (c->u.a.lensofar == 4) {
5745 c->u.a.totallen =
5746 4 + GET_32BIT(c->u.a.msglen);
5747 c->u.a.message = snewn(c->u.a.totallen,
5748 unsigned char);
5749 memcpy(c->u.a.message, c->u.a.msglen, 4);
5750 }
5751 if (c->u.a.lensofar >= 4 && length > 0) {
5752 int l =
5753 min(c->u.a.totallen - c->u.a.lensofar,
5754 length);
5755 memcpy(c->u.a.message + c->u.a.lensofar,
5756 data, l);
5757 data += l;
5758 length -= l;
5759 c->u.a.lensofar += l;
5760 }
5761 if (c->u.a.lensofar == c->u.a.totallen) {
5762 void *reply;
5763 int replylen;
5764 if (agent_query(c->u.a.message,
5765 c->u.a.totallen,
5766 &reply, &replylen,
5767 ssh_agentf_callback, c))
5768 ssh_agentf_callback(c, reply, replylen);
5769 sfree(c->u.a.message);
5770 c->u.a.lensofar = 0;
5771 }
5772 }
5773 bufsize = 0;
5774 break;
5775 }
5776 /*
5777 * If we are not buffering too much data,
5778 * enlarge the window again at the remote side.
5779 */
5780 if (bufsize < OUR_V2_WINSIZE)
5781 ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
5782 }
5783 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_EOF) {
5784 unsigned i = ssh2_pkt_getuint32(ssh);
5785 struct ssh_channel *c;
5786
5787 c = find234(ssh->channels, &i, ssh_channelfind);
5788 if (!c)
5789 continue; /* nonexistent channel */
5790
5791 if (c->type == CHAN_X11) {
5792 /*
5793 * Remote EOF on an X11 channel means we should
5794 * wrap up and close the channel ourselves.
5795 */
5796 x11_close(c->u.x11.s);
5797 sshfwd_close(c);
5798 } else if (c->type == CHAN_AGENT) {
5799 sshfwd_close(c);
5800 } else if (c->type == CHAN_SOCKDATA) {
5801 pfd_close(c->u.pfd.s);
5802 sshfwd_close(c);
5803 }
5804 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_CLOSE) {
5805 unsigned i = ssh2_pkt_getuint32(ssh);
5806 struct ssh_channel *c;
5807
5808 c = find234(ssh->channels, &i, ssh_channelfind);
5809 if (!c || ((int)c->remoteid) == -1) {
5810 bombout(("Received CHANNEL_CLOSE for %s channel %d\n",
5811 c ? "half-open" : "nonexistent", i));
5812 crStopV;
5813 }
5814 /* Do pre-close processing on the channel. */
5815 switch (c->type) {
5816 case CHAN_MAINSESSION:
5817 break; /* nothing to see here, move along */
5818 case CHAN_X11:
5819 if (c->u.x11.s != NULL)
5820 x11_close(c->u.x11.s);
5821 sshfwd_close(c);
5822 break;
5823 case CHAN_AGENT:
5824 sshfwd_close(c);
5825 break;
5826 case CHAN_SOCKDATA:
5827 if (c->u.pfd.s != NULL)
5828 pfd_close(c->u.pfd.s);
5829 sshfwd_close(c);
5830 break;
5831 }
5832 if (c->closes == 0) {
5833 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
5834 ssh2_pkt_adduint32(ssh, c->remoteid);
5835 ssh2_pkt_send(ssh);
5836 }
5837 del234(ssh->channels, c);
5838 bufchain_clear(&c->v.v2.outbuffer);
5839 sfree(c);
5840
5841 /*
5842 * See if that was the last channel left open.
5843 */
5844 if (count234(ssh->channels) == 0) {
5845 logevent("All channels closed. Disconnecting");
5846 #if 0
5847 /*
5848 * We used to send SSH_MSG_DISCONNECT here,
5849 * because I'd believed that _every_ conforming
5850 * SSH2 connection had to end with a disconnect
5851 * being sent by at least one side; apparently
5852 * I was wrong and it's perfectly OK to
5853 * unceremoniously slam the connection shut
5854 * when you're done, and indeed OpenSSH feels
5855 * this is more polite than sending a
5856 * DISCONNECT. So now we don't.
5857 */
5858 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5859 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5860 ssh2_pkt_addstring(ssh, "All open channels closed");
5861 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5862 ssh2_pkt_send(ssh);
5863 #endif
5864 ssh_closing((Plug)ssh, NULL, 0, 0);
5865 crStopV;
5866 }
5867 continue; /* remote sends close; ignore (FIXME) */
5868 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5869 unsigned i = ssh2_pkt_getuint32(ssh);
5870 struct ssh_channel *c;
5871 c = find234(ssh->channels, &i, ssh_channelfind);
5872 if (!c || c->closes)
5873 continue; /* nonexistent or closing channel */
5874 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5875 s->try_send = TRUE;
5876 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
5877 unsigned i = ssh2_pkt_getuint32(ssh);
5878 struct ssh_channel *c;
5879 c = find234(ssh->channels, &i, ssh_channelfind);
5880 if (!c)
5881 continue; /* nonexistent channel */
5882 if (c->type != CHAN_SOCKDATA_DORMANT)
5883 continue; /* dunno why they're confirming this */
5884 c->remoteid = ssh2_pkt_getuint32(ssh);
5885 c->type = CHAN_SOCKDATA;
5886 c->v.v2.remwindow = ssh2_pkt_getuint32(ssh);
5887 c->v.v2.remmaxpkt = ssh2_pkt_getuint32(ssh);
5888 if (c->u.pfd.s)
5889 pfd_confirm(c->u.pfd.s);
5890 if (c->closes) {
5891 /*
5892 * We have a pending close on this channel,
5893 * which we decided on before the server acked
5894 * the channel open. So now we know the
5895 * remoteid, we can close it again.
5896 */
5897 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
5898 ssh2_pkt_adduint32(ssh, c->remoteid);
5899 ssh2_pkt_send(ssh);
5900 }
5901 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN_FAILURE) {
5902 unsigned i = ssh2_pkt_getuint32(ssh);
5903 struct ssh_channel *c;
5904 c = find234(ssh->channels, &i, ssh_channelfind);
5905 if (!c)
5906 continue; /* nonexistent channel */
5907 if (c->type != CHAN_SOCKDATA_DORMANT)
5908 continue; /* dunno why they're failing this */
5909
5910 logevent("Forwarded connection refused by server");
5911
5912 pfd_close(c->u.pfd.s);
5913
5914 del234(ssh->channels, c);
5915 sfree(c);
5916 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_REQUEST) {
5917 unsigned localid;
5918 char *type;
5919 int typelen, want_reply;
5920 struct ssh_channel *c;
5921
5922 localid = ssh2_pkt_getuint32(ssh);
5923 ssh2_pkt_getstring(ssh, &type, &typelen);
5924 want_reply = ssh2_pkt_getbool(ssh);
5925
5926 /*
5927 * First, check that the channel exists. Otherwise,
5928 * we can instantly disconnect with a rude message.
5929 */
5930 c = find234(ssh->channels, &localid, ssh_channelfind);
5931 if (!c) {
5932 char buf[80];
5933 sprintf(buf, "Received channel request for nonexistent"
5934 " channel %d", localid);
5935 logevent(buf);
5936 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5937 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5938 ssh2_pkt_addstring(ssh, buf);
5939 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5940 ssh2_pkt_send(ssh);
5941 connection_fatal(ssh->frontend, "%s", buf);
5942 ssh_closing((Plug)ssh, NULL, 0, 0);
5943 crStopV;
5944 }
5945
5946 /*
5947 * Having got the channel number, we now look at
5948 * the request type string to see if it's something
5949 * we recognise.
5950 */
5951 if (typelen == 11 && !memcmp(type, "exit-status", 11) &&
5952 c == ssh->mainchan) {
5953 /* We recognise "exit-status" on the primary channel. */
5954 char buf[100];
5955 ssh->exitcode = ssh2_pkt_getuint32(ssh);
5956 sprintf(buf, "Server sent command exit status %d",
5957 ssh->exitcode);
5958 logevent(buf);
5959 if (want_reply) {
5960 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_SUCCESS);
5961 ssh2_pkt_adduint32(ssh, c->remoteid);
5962 ssh2_pkt_send(ssh);
5963 }
5964 } else {
5965 /*
5966 * This is a channel request we don't know
5967 * about, so we now either ignore the request
5968 * or respond with CHANNEL_FAILURE, depending
5969 * on want_reply.
5970 */
5971 if (want_reply) {
5972 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_FAILURE);
5973 ssh2_pkt_adduint32(ssh, c->remoteid);
5974 ssh2_pkt_send(ssh);
5975 }
5976 }
5977 } else if (ssh->pktin.type == SSH2_MSG_GLOBAL_REQUEST) {
5978 char *type;
5979 int typelen, want_reply;
5980
5981 ssh2_pkt_getstring(ssh, &type, &typelen);
5982 want_reply = ssh2_pkt_getbool(ssh);
5983
5984 /*
5985 * We currently don't support any global requests
5986 * at all, so we either ignore the request or
5987 * respond with REQUEST_FAILURE, depending on
5988 * want_reply.
5989 */
5990 if (want_reply) {
5991 ssh2_pkt_init(ssh, SSH2_MSG_REQUEST_FAILURE);
5992 ssh2_pkt_send(ssh);
5993 }
5994 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN) {
5995 char *type;
5996 int typelen;
5997 char *peeraddr;
5998 int peeraddrlen;
5999 int peerport;
6000 char *error = NULL;
6001 struct ssh_channel *c;
6002 unsigned remid, winsize, pktsize;
6003 ssh2_pkt_getstring(ssh, &type, &typelen);
6004 c = snew(struct ssh_channel);
6005 c->ssh = ssh;
6006
6007 remid = ssh2_pkt_getuint32(ssh);
6008 winsize = ssh2_pkt_getuint32(ssh);
6009 pktsize = ssh2_pkt_getuint32(ssh);
6010
6011 if (typelen == 3 && !memcmp(type, "x11", 3)) {
6012 char *addrstr;
6013
6014 ssh2_pkt_getstring(ssh, &peeraddr, &peeraddrlen);
6015 addrstr = snewn(peeraddrlen+1, char);
6016 memcpy(addrstr, peeraddr, peeraddrlen);
6017 peeraddr[peeraddrlen] = '\0';
6018 peerport = ssh2_pkt_getuint32(ssh);
6019
6020 if (!ssh->X11_fwd_enabled)
6021 error = "X11 forwarding is not enabled";
6022 else if (x11_init(&c->u.x11.s, ssh->cfg.x11_display, c,
6023 ssh->x11auth, addrstr, peerport,
6024 &ssh->cfg) != NULL) {
6025 error = "Unable to open an X11 connection";
6026 } else {
6027 c->type = CHAN_X11;
6028 }
6029
6030 sfree(addrstr);
6031 } else if (typelen == 15 &&
6032 !memcmp(type, "forwarded-tcpip", 15)) {
6033 struct ssh_rportfwd pf, *realpf;
6034 char *dummy;
6035 int dummylen;
6036 ssh2_pkt_getstring(ssh, &dummy, &dummylen);/* skip address */
6037 pf.sport = ssh2_pkt_getuint32(ssh);
6038 ssh2_pkt_getstring(ssh, &peeraddr, &peeraddrlen);
6039 peerport = ssh2_pkt_getuint32(ssh);
6040 realpf = find234(ssh->rportfwds, &pf, NULL);
6041 if (realpf == NULL) {
6042 error = "Remote port is not recognised";
6043 } else {
6044 const char *e = pfd_newconnect(&c->u.pfd.s,
6045 realpf->dhost,
6046 realpf->dport, c,
6047 &ssh->cfg);
6048 logeventf(ssh, "Received remote port open request"
6049 " for %s:%d", realpf->dhost, realpf->dport);
6050 if (e != NULL) {
6051 logeventf(ssh, "Port open failed: %s", e);
6052 error = "Port open failed";
6053 } else {
6054 logevent("Forwarded port opened successfully");
6055 c->type = CHAN_SOCKDATA;
6056 }
6057 }
6058 } else if (typelen == 22 &&
6059 !memcmp(type, "auth-agent@openssh.com", 3)) {
6060 if (!ssh->agentfwd_enabled)
6061 error = "Agent forwarding is not enabled";
6062 else {
6063 c->type = CHAN_AGENT; /* identify channel type */
6064 c->u.a.lensofar = 0;
6065 }
6066 } else {
6067 error = "Unsupported channel type requested";
6068 }
6069
6070 c->remoteid = remid;
6071 if (error) {
6072 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN_FAILURE);
6073 ssh2_pkt_adduint32(ssh, c->remoteid);
6074 ssh2_pkt_adduint32(ssh, SSH2_OPEN_CONNECT_FAILED);
6075 ssh2_pkt_addstring(ssh, error);
6076 ssh2_pkt_addstring(ssh, "en"); /* language tag */
6077 ssh2_pkt_send(ssh);
6078 sfree(c);
6079 } else {
6080 c->localid = alloc_channel_id(ssh);
6081 c->closes = 0;
6082 c->v.v2.locwindow = OUR_V2_WINSIZE;
6083 c->v.v2.remwindow = winsize;
6084 c->v.v2.remmaxpkt = pktsize;
6085 bufchain_init(&c->v.v2.outbuffer);
6086 add234(ssh->channels, c);
6087 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
6088 ssh2_pkt_adduint32(ssh, c->remoteid);
6089 ssh2_pkt_adduint32(ssh, c->localid);
6090 ssh2_pkt_adduint32(ssh, c->v.v2.locwindow);
6091 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
6092 ssh2_pkt_send(ssh);
6093 }
6094 } else {
6095 bombout(("Strange packet received: type %d", ssh->pktin.type));
6096 crStopV;
6097 }
6098 } else {
6099 /*
6100 * We have spare data. Add it to the channel buffer.
6101 */
6102 ssh2_add_channel_data(ssh->mainchan, (char *)in, inlen);
6103 s->try_send = TRUE;
6104 }
6105 if (s->try_send) {
6106 int i;
6107 struct ssh_channel *c;
6108 /*
6109 * Try to send data on all channels if we can.
6110 */
6111 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
6112 int bufsize;
6113 if (c->closes)
6114 continue; /* don't send on closing channels */
6115 bufsize = ssh2_try_send(c);
6116 if (bufsize == 0) {
6117 switch (c->type) {
6118 case CHAN_MAINSESSION:
6119 /* stdin need not receive an unthrottle
6120 * notification since it will be polled */
6121 break;
6122 case CHAN_X11:
6123 x11_unthrottle(c->u.x11.s);
6124 break;
6125 case CHAN_AGENT:
6126 /* agent sockets are request/response and need no
6127 * buffer management */
6128 break;
6129 case CHAN_SOCKDATA:
6130 pfd_unthrottle(c->u.pfd.s);
6131 break;
6132 }
6133 }
6134 }
6135 }
6136 }
6137
6138 crFinishV;
6139 }
6140
6141 /*
6142 * Handle the top-level SSH2 protocol.
6143 */
6144 static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
6145 {
6146 if (do_ssh2_transport(ssh, in, inlen, ispkt) == 0)
6147 return;
6148 do_ssh2_authconn(ssh, in, inlen, ispkt);
6149 }
6150
6151 /*
6152 * Called to set up the connection.
6153 *
6154 * Returns an error message, or NULL on success.
6155 */
6156 static const char *ssh_init(void *frontend_handle, void **backend_handle,
6157 Config *cfg,
6158 char *host, int port, char **realhost, int nodelay)
6159 {
6160 const char *p;
6161 Ssh ssh;
6162
6163 ssh = snew(struct ssh_tag);
6164 ssh->cfg = *cfg; /* STRUCTURE COPY */
6165 ssh->version = 0; /* when not ready yet */
6166 ssh->s = NULL;
6167 ssh->cipher = NULL;
6168 ssh->v1_cipher_ctx = NULL;
6169 ssh->crcda_ctx = NULL;
6170 ssh->cscipher = NULL;
6171 ssh->cs_cipher_ctx = NULL;
6172 ssh->sccipher = NULL;
6173 ssh->sc_cipher_ctx = NULL;
6174 ssh->csmac = NULL;
6175 ssh->cs_mac_ctx = NULL;
6176 ssh->scmac = NULL;
6177 ssh->sc_mac_ctx = NULL;
6178 ssh->cscomp = NULL;
6179 ssh->cs_comp_ctx = NULL;
6180 ssh->sccomp = NULL;
6181 ssh->sc_comp_ctx = NULL;
6182 ssh->kex = NULL;
6183 ssh->kex_ctx = NULL;
6184 ssh->hostkey = NULL;
6185 ssh->exitcode = -1;
6186 ssh->state = SSH_STATE_PREPACKET;
6187 ssh->size_needed = FALSE;
6188 ssh->eof_needed = FALSE;
6189 ssh->ldisc = NULL;
6190 ssh->logctx = NULL;
6191 {
6192 static const struct Packet empty = { 0, 0, NULL, NULL, 0 };
6193 ssh->pktin = ssh->pktout = empty;
6194 }
6195 ssh->deferred_send_data = NULL;
6196 ssh->deferred_len = 0;
6197 ssh->deferred_size = 0;
6198 ssh->fallback_cmd = 0;
6199 ssh->pkt_ctx = 0;
6200 ssh->x11auth = NULL;
6201 ssh->v1_compressing = FALSE;
6202 ssh->v2_outgoing_sequence = 0;
6203 ssh->ssh1_rdpkt_crstate = 0;
6204 ssh->ssh2_rdpkt_crstate = 0;
6205 ssh->do_ssh_init_crstate = 0;
6206 ssh->ssh_gotdata_crstate = 0;
6207 ssh->ssh1_protocol_crstate = 0;
6208 ssh->do_ssh1_login_crstate = 0;
6209 ssh->do_ssh2_transport_crstate = 0;
6210 ssh->do_ssh2_authconn_crstate = 0;
6211 ssh->do_ssh_init_state = NULL;
6212 ssh->do_ssh1_login_state = NULL;
6213 ssh->do_ssh2_transport_state = NULL;
6214 ssh->do_ssh2_authconn_state = NULL;
6215 ssh->mainchan = NULL;
6216 ssh->throttled_all = 0;
6217 ssh->v1_stdout_throttling = 0;
6218
6219 *backend_handle = ssh;
6220
6221 #ifdef MSCRYPTOAPI
6222 if (crypto_startup() == 0)
6223 return "Microsoft high encryption pack not installed!";
6224 #endif
6225
6226 ssh->frontend = frontend_handle;
6227 ssh->term_width = ssh->cfg.width;
6228 ssh->term_height = ssh->cfg.height;
6229
6230 ssh->channels = NULL;
6231 ssh->rportfwds = NULL;
6232
6233 ssh->send_ok = 0;
6234 ssh->editing = 0;
6235 ssh->echoing = 0;
6236 ssh->v1_throttle_count = 0;
6237 ssh->overall_bufsize = 0;
6238 ssh->fallback_cmd = 0;
6239
6240 ssh->protocol = NULL;
6241
6242 p = connect_to_host(ssh, host, port, realhost, nodelay);
6243 if (p != NULL)
6244 return p;
6245
6246 return NULL;
6247 }
6248
6249 static void ssh_free(void *handle)
6250 {
6251 Ssh ssh = (Ssh) handle;
6252 struct ssh_channel *c;
6253 struct ssh_rportfwd *pf;
6254
6255 if (ssh->v1_cipher_ctx)
6256 ssh->cipher->free_context(ssh->v1_cipher_ctx);
6257 if (ssh->cs_cipher_ctx)
6258 ssh->cscipher->free_context(ssh->cs_cipher_ctx);
6259 if (ssh->sc_cipher_ctx)
6260 ssh->sccipher->free_context(ssh->sc_cipher_ctx);
6261 if (ssh->cs_mac_ctx)
6262 ssh->csmac->free_context(ssh->cs_mac_ctx);
6263 if (ssh->sc_mac_ctx)
6264 ssh->scmac->free_context(ssh->sc_mac_ctx);
6265 if (ssh->cs_comp_ctx)
6266 ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
6267 if (ssh->sc_comp_ctx)
6268 ssh->sccomp->compress_cleanup(ssh->sc_comp_ctx);
6269 if (ssh->kex_ctx)
6270 dh_cleanup(ssh->kex_ctx);
6271 sfree(ssh->savedhost);
6272
6273 if (ssh->channels) {
6274 while ((c = delpos234(ssh->channels, 0)) != NULL) {
6275 switch (c->type) {
6276 case CHAN_X11:
6277 if (c->u.x11.s != NULL)
6278 x11_close(c->u.x11.s);
6279 break;
6280 case CHAN_SOCKDATA:
6281 if (c->u.pfd.s != NULL)
6282 pfd_close(c->u.pfd.s);
6283 break;
6284 }
6285 sfree(c);
6286 }
6287 freetree234(ssh->channels);
6288 }
6289
6290 if (ssh->rportfwds) {
6291 while ((pf = delpos234(ssh->rportfwds, 0)) != NULL)
6292 sfree(pf);
6293 freetree234(ssh->rportfwds);
6294 }
6295 sfree(ssh->deferred_send_data);
6296 if (ssh->x11auth)
6297 x11_free_auth(ssh->x11auth);
6298 sfree(ssh->do_ssh_init_state);
6299 sfree(ssh->do_ssh1_login_state);
6300 sfree(ssh->do_ssh2_transport_state);
6301 sfree(ssh->do_ssh2_authconn_state);
6302 if (ssh->pktout.data) {
6303 sfree(ssh->pktout.data);
6304 ssh->pktout.data = NULL;
6305 }
6306 if (ssh->pktin.data) {
6307 sfree(ssh->pktin.data);
6308 ssh->pktin.data = NULL;
6309 }
6310 if (ssh->crcda_ctx) {
6311 crcda_free_context(ssh->crcda_ctx);
6312 ssh->crcda_ctx = NULL;
6313 }
6314 if (ssh->logctx) {
6315 log_free(ssh->logctx);
6316 ssh->logctx = NULL;
6317 }
6318 if (ssh->s)
6319 ssh_do_close(ssh);
6320 sfree(ssh);
6321 }
6322
6323 /*
6324 * Reconfigure the SSH backend.
6325 *
6326 * Currently, this function does nothing very useful. In future,
6327 * however, we could do some handy things with it. For example, we
6328 * could make the port forwarding configurer active in the Change
6329 * Settings box, and this routine could close down existing
6330 * forwardings and open up new ones in response to changes.
6331 */
6332 static void ssh_reconfig(void *handle, Config *cfg)
6333 {
6334 Ssh ssh = (Ssh) handle;
6335 ssh->cfg = *cfg; /* STRUCTURE COPY */
6336 }
6337
6338 /*
6339 * Called to send data down the Telnet connection.
6340 */
6341 static int ssh_send(void *handle, char *buf, int len)
6342 {
6343 Ssh ssh = (Ssh) handle;
6344
6345 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
6346 return 0;
6347
6348 ssh->protocol(ssh, (unsigned char *)buf, len, 0);
6349
6350 return ssh_sendbuffer(ssh);
6351 }
6352
6353 /*
6354 * Called to query the current amount of buffered stdin data.
6355 */
6356 static int ssh_sendbuffer(void *handle)
6357 {
6358 Ssh ssh = (Ssh) handle;
6359 int override_value;
6360
6361 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
6362 return 0;
6363
6364 /*
6365 * If the SSH socket itself has backed up, add the total backup
6366 * size on that to any individual buffer on the stdin channel.
6367 */
6368 override_value = 0;
6369 if (ssh->throttled_all)
6370 override_value = ssh->overall_bufsize;
6371
6372 if (ssh->version == 1) {
6373 return override_value;
6374 } else if (ssh->version == 2) {
6375 if (!ssh->mainchan || ssh->mainchan->closes > 0)
6376 return override_value;
6377 else
6378 return (override_value +
6379 bufchain_size(&ssh->mainchan->v.v2.outbuffer));
6380 }
6381
6382 return 0;
6383 }
6384
6385 /*
6386 * Called to set the size of the window from SSH's POV.
6387 */
6388 static void ssh_size(void *handle, int width, int height)
6389 {
6390 Ssh ssh = (Ssh) handle;
6391
6392 ssh->term_width = width;
6393 ssh->term_height = height;
6394
6395 switch (ssh->state) {
6396 case SSH_STATE_BEFORE_SIZE:
6397 case SSH_STATE_PREPACKET:
6398 case SSH_STATE_CLOSED:
6399 break; /* do nothing */
6400 case SSH_STATE_INTERMED:
6401 ssh->size_needed = TRUE; /* buffer for later */
6402 break;
6403 case SSH_STATE_SESSION:
6404 if (!ssh->cfg.nopty) {
6405 if (ssh->version == 1) {
6406 send_packet(ssh, SSH1_CMSG_WINDOW_SIZE,
6407 PKT_INT, ssh->term_height,
6408 PKT_INT, ssh->term_width,
6409 PKT_INT, 0, PKT_INT, 0, PKT_END);
6410 } else {
6411 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
6412 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
6413 ssh2_pkt_addstring(ssh, "window-change");
6414 ssh2_pkt_addbool(ssh, 0);
6415 ssh2_pkt_adduint32(ssh, ssh->term_width);
6416 ssh2_pkt_adduint32(ssh, ssh->term_height);
6417 ssh2_pkt_adduint32(ssh, 0);
6418 ssh2_pkt_adduint32(ssh, 0);
6419 ssh2_pkt_send(ssh);
6420 }
6421 }
6422 break;
6423 }
6424 }
6425
6426 /*
6427 * Return a list of the special codes that make sense in this
6428 * protocol.
6429 */
6430 static const struct telnet_special *ssh_get_specials(void *handle)
6431 {
6432 Ssh ssh = (Ssh) handle;
6433
6434 if (ssh->version == 1) {
6435 static const struct telnet_special ssh1_specials[] = {
6436 {"IGNORE message", TS_NOP},
6437 {NULL, 0}
6438 };
6439 return ssh1_specials;
6440 } else if (ssh->version == 2) {
6441 static const struct telnet_special ssh2_specials[] = {
6442 {"Break", TS_BRK},
6443 {"IGNORE message", TS_NOP},
6444 {NULL, 0}
6445 };
6446 return ssh2_specials;
6447 } else
6448 return NULL;
6449 }
6450
6451 /*
6452 * Send Telnet special codes. TS_EOF is useful for `plink', so you
6453 * can send an EOF and collect resulting output (e.g. `plink
6454 * hostname sort').
6455 */
6456 static void ssh_special(void *handle, Telnet_Special code)
6457 {
6458 Ssh ssh = (Ssh) handle;
6459
6460 if (code == TS_EOF) {
6461 if (ssh->state != SSH_STATE_SESSION) {
6462 /*
6463 * Buffer the EOF in case we are pre-SESSION, so we can
6464 * send it as soon as we reach SESSION.
6465 */
6466 if (code == TS_EOF)
6467 ssh->eof_needed = TRUE;
6468 return;
6469 }
6470 if (ssh->version == 1) {
6471 send_packet(ssh, SSH1_CMSG_EOF, PKT_END);
6472 } else {
6473 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_EOF);
6474 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
6475 ssh2_pkt_send(ssh);
6476 }
6477 logevent("Sent EOF message");
6478 } else if (code == TS_PING || code == TS_NOP) {
6479 if (ssh->state == SSH_STATE_CLOSED
6480 || ssh->state == SSH_STATE_PREPACKET) return;
6481 if (ssh->version == 1) {
6482 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE))
6483 send_packet(ssh, SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
6484 } else {
6485 ssh2_pkt_init(ssh, SSH2_MSG_IGNORE);
6486 ssh2_pkt_addstring_start(ssh);
6487 ssh2_pkt_send(ssh);
6488 }
6489 } else if (code == TS_BRK) {
6490 if (ssh->state == SSH_STATE_CLOSED
6491 || ssh->state == SSH_STATE_PREPACKET) return;
6492 if (ssh->version == 1) {
6493 logevent("Unable to send BREAK signal in SSH1");
6494 } else {
6495 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
6496 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
6497 ssh2_pkt_addstring(ssh, "break");
6498 ssh2_pkt_addbool(ssh, 0);
6499 ssh2_pkt_adduint32(ssh, 0); /* default break length */
6500 ssh2_pkt_send(ssh);
6501 }
6502 } else {
6503 /* do nothing */
6504 }
6505 }
6506
6507 void *new_sock_channel(void *handle, Socket s)
6508 {
6509 Ssh ssh = (Ssh) handle;
6510 struct ssh_channel *c;
6511 c = snew(struct ssh_channel);
6512 c->ssh = ssh;
6513
6514 if (c) {
6515 c->remoteid = -1; /* to be set when open confirmed */
6516 c->localid = alloc_channel_id(ssh);
6517 c->closes = 0;
6518 c->type = CHAN_SOCKDATA_DORMANT;/* identify channel type */
6519 c->u.pfd.s = s;
6520 bufchain_init(&c->v.v2.outbuffer);
6521 add234(ssh->channels, c);
6522 }
6523 return c;
6524 }
6525
6526 /*
6527 * This is called when stdout/stderr (the entity to which
6528 * from_backend sends data) manages to clear some backlog.
6529 */
6530 static void ssh_unthrottle(void *handle, int bufsize)
6531 {
6532 Ssh ssh = (Ssh) handle;
6533 if (ssh->version == 1) {
6534 if (ssh->v1_stdout_throttling && bufsize < SSH1_BUFFER_LIMIT) {
6535 ssh->v1_stdout_throttling = 0;
6536 ssh1_throttle(ssh, -1);
6537 }
6538 } else {
6539 if (ssh->mainchan && ssh->mainchan->closes == 0)
6540 ssh2_set_window(ssh->mainchan, OUR_V2_WINSIZE - bufsize);
6541 }
6542 }
6543
6544 void ssh_send_port_open(void *channel, char *hostname, int port, char *org)
6545 {
6546 struct ssh_channel *c = (struct ssh_channel *)channel;
6547 Ssh ssh = c->ssh;
6548
6549 logeventf(ssh, "Opening forwarded connection to %s:%d", hostname, port);
6550
6551 if (ssh->version == 1) {
6552 send_packet(ssh, SSH1_MSG_PORT_OPEN,
6553 PKT_INT, c->localid,
6554 PKT_STR, hostname,
6555 PKT_INT, port,
6556 //PKT_STR, <org:orgport>,
6557 PKT_END);
6558 } else {
6559 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN);
6560 ssh2_pkt_addstring(ssh, "direct-tcpip");
6561 ssh2_pkt_adduint32(ssh, c->localid);
6562 c->v.v2.locwindow = OUR_V2_WINSIZE;
6563 ssh2_pkt_adduint32(ssh, c->v.v2.locwindow);/* our window size */
6564 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
6565 ssh2_pkt_addstring(ssh, hostname);
6566 ssh2_pkt_adduint32(ssh, port);
6567 /*
6568 * We make up values for the originator data; partly it's
6569 * too much hassle to keep track, and partly I'm not
6570 * convinced the server should be told details like that
6571 * about my local network configuration.
6572 */
6573 ssh2_pkt_addstring(ssh, "client-side-connection");
6574 ssh2_pkt_adduint32(ssh, 0);
6575 ssh2_pkt_send(ssh);
6576 }
6577 }
6578
6579
6580 static Socket ssh_socket(void *handle)
6581 {
6582 Ssh ssh = (Ssh) handle;
6583 return ssh->s;
6584 }
6585
6586 static int ssh_sendok(void *handle)
6587 {
6588 Ssh ssh = (Ssh) handle;
6589 return ssh->send_ok;
6590 }
6591
6592 static int ssh_ldisc(void *handle, int option)
6593 {
6594 Ssh ssh = (Ssh) handle;
6595 if (option == LD_ECHO)
6596 return ssh->echoing;
6597 if (option == LD_EDIT)
6598 return ssh->editing;
6599 return FALSE;
6600 }
6601
6602 static void ssh_provide_ldisc(void *handle, void *ldisc)
6603 {
6604 Ssh ssh = (Ssh) handle;
6605 ssh->ldisc = ldisc;
6606 }
6607
6608 static void ssh_provide_logctx(void *handle, void *logctx)
6609 {
6610 Ssh ssh = (Ssh) handle;
6611 ssh->logctx = logctx;
6612 }
6613
6614 static int ssh_return_exitcode(void *handle)
6615 {
6616 Ssh ssh = (Ssh) handle;
6617 if (ssh->s != NULL)
6618 return -1;
6619 else
6620 return (ssh->exitcode >= 0 ? ssh->exitcode : 0);
6621 }
6622
6623 /*
6624 * Gross hack: pscp will try to start SFTP but fall back to scp1 if
6625 * that fails. This variable is the means by which scp.c can reach
6626 * into the SSH code and find out which one it got.
6627 */
6628 extern int ssh_fallback_cmd(void *handle)
6629 {
6630 Ssh ssh = (Ssh) handle;
6631 return ssh->fallback_cmd;
6632 }
6633
6634 Backend ssh_backend = {
6635 ssh_init,
6636 ssh_free,
6637 ssh_reconfig,
6638 ssh_send,
6639 ssh_sendbuffer,
6640 ssh_size,
6641 ssh_special,
6642 ssh_get_specials,
6643 ssh_socket,
6644 ssh_return_exitcode,
6645 ssh_sendok,
6646 ssh_ldisc,
6647 ssh_provide_ldisc,
6648 ssh_provide_logctx,
6649 ssh_unthrottle,
6650 22
6651 };
Local modifications for Simon Tatham's `PuTTY' SSH client and terminal emulator