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[u/mdw/putty] / ssh.c
1 #include <stdio.h>
2 #include <stdlib.h>
3 #include <stdarg.h>
4 #include <assert.h>
5
6 #include "putty.h"
7 #include "tree234.h"
8 #include "ssh.h"
9
10 #ifndef FALSE
11 #define FALSE 0
12 #endif
13 #ifndef TRUE
14 #define TRUE 1
15 #endif
16
17 #define SSH1_MSG_DISCONNECT 1 /* 0x1 */
18 #define SSH1_SMSG_PUBLIC_KEY 2 /* 0x2 */
19 #define SSH1_CMSG_SESSION_KEY 3 /* 0x3 */
20 #define SSH1_CMSG_USER 4 /* 0x4 */
21 #define SSH1_CMSG_AUTH_RSA 6 /* 0x6 */
22 #define SSH1_SMSG_AUTH_RSA_CHALLENGE 7 /* 0x7 */
23 #define SSH1_CMSG_AUTH_RSA_RESPONSE 8 /* 0x8 */
24 #define SSH1_CMSG_AUTH_PASSWORD 9 /* 0x9 */
25 #define SSH1_CMSG_REQUEST_PTY 10 /* 0xa */
26 #define SSH1_CMSG_WINDOW_SIZE 11 /* 0xb */
27 #define SSH1_CMSG_EXEC_SHELL 12 /* 0xc */
28 #define SSH1_CMSG_EXEC_CMD 13 /* 0xd */
29 #define SSH1_SMSG_SUCCESS 14 /* 0xe */
30 #define SSH1_SMSG_FAILURE 15 /* 0xf */
31 #define SSH1_CMSG_STDIN_DATA 16 /* 0x10 */
32 #define SSH1_SMSG_STDOUT_DATA 17 /* 0x11 */
33 #define SSH1_SMSG_STDERR_DATA 18 /* 0x12 */
34 #define SSH1_CMSG_EOF 19 /* 0x13 */
35 #define SSH1_SMSG_EXIT_STATUS 20 /* 0x14 */
36 #define SSH1_MSG_CHANNEL_OPEN_CONFIRMATION 21 /* 0x15 */
37 #define SSH1_MSG_CHANNEL_OPEN_FAILURE 22 /* 0x16 */
38 #define SSH1_MSG_CHANNEL_DATA 23 /* 0x17 */
39 #define SSH1_MSG_CHANNEL_CLOSE 24 /* 0x18 */
40 #define SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION 25 /* 0x19 */
41 #define SSH1_SMSG_X11_OPEN 27 /* 0x1b */
42 #define SSH1_CMSG_PORT_FORWARD_REQUEST 28 /* 0x1c */
43 #define SSH1_MSG_PORT_OPEN 29 /* 0x1d */
44 #define SSH1_CMSG_AGENT_REQUEST_FORWARDING 30 /* 0x1e */
45 #define SSH1_SMSG_AGENT_OPEN 31 /* 0x1f */
46 #define SSH1_MSG_IGNORE 32 /* 0x20 */
47 #define SSH1_CMSG_EXIT_CONFIRMATION 33 /* 0x21 */
48 #define SSH1_CMSG_X11_REQUEST_FORWARDING 34 /* 0x22 */
49 #define SSH1_CMSG_AUTH_RHOSTS_RSA 35 /* 0x23 */
50 #define SSH1_MSG_DEBUG 36 /* 0x24 */
51 #define SSH1_CMSG_REQUEST_COMPRESSION 37 /* 0x25 */
52 #define SSH1_CMSG_AUTH_TIS 39 /* 0x27 */
53 #define SSH1_SMSG_AUTH_TIS_CHALLENGE 40 /* 0x28 */
54 #define SSH1_CMSG_AUTH_TIS_RESPONSE 41 /* 0x29 */
55 #define SSH1_CMSG_AUTH_CCARD 70 /* 0x46 */
56 #define SSH1_SMSG_AUTH_CCARD_CHALLENGE 71 /* 0x47 */
57 #define SSH1_CMSG_AUTH_CCARD_RESPONSE 72 /* 0x48 */
58
59 #define SSH1_AUTH_TIS 5 /* 0x5 */
60 #define SSH1_AUTH_CCARD 16 /* 0x10 */
61
62 #define SSH1_PROTOFLAG_SCREEN_NUMBER 1 /* 0x1 */
63 /* Mask for protoflags we will echo back to server if seen */
64 #define SSH1_PROTOFLAGS_SUPPORTED 0 /* 0x1 */
65
66 #define SSH2_MSG_DISCONNECT 1 /* 0x1 */
67 #define SSH2_MSG_IGNORE 2 /* 0x2 */
68 #define SSH2_MSG_UNIMPLEMENTED 3 /* 0x3 */
69 #define SSH2_MSG_DEBUG 4 /* 0x4 */
70 #define SSH2_MSG_SERVICE_REQUEST 5 /* 0x5 */
71 #define SSH2_MSG_SERVICE_ACCEPT 6 /* 0x6 */
72 #define SSH2_MSG_KEXINIT 20 /* 0x14 */
73 #define SSH2_MSG_NEWKEYS 21 /* 0x15 */
74 #define SSH2_MSG_KEXDH_INIT 30 /* 0x1e */
75 #define SSH2_MSG_KEXDH_REPLY 31 /* 0x1f */
76 #define SSH2_MSG_KEX_DH_GEX_REQUEST 30 /* 0x1e */
77 #define SSH2_MSG_KEX_DH_GEX_GROUP 31 /* 0x1f */
78 #define SSH2_MSG_KEX_DH_GEX_INIT 32 /* 0x20 */
79 #define SSH2_MSG_KEX_DH_GEX_REPLY 33 /* 0x21 */
80 #define SSH2_MSG_USERAUTH_REQUEST 50 /* 0x32 */
81 #define SSH2_MSG_USERAUTH_FAILURE 51 /* 0x33 */
82 #define SSH2_MSG_USERAUTH_SUCCESS 52 /* 0x34 */
83 #define SSH2_MSG_USERAUTH_BANNER 53 /* 0x35 */
84 #define SSH2_MSG_USERAUTH_PK_OK 60 /* 0x3c */
85 #define SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ 60 /* 0x3c */
86 #define SSH2_MSG_USERAUTH_INFO_REQUEST 60 /* 0x3c */
87 #define SSH2_MSG_USERAUTH_INFO_RESPONSE 61 /* 0x3d */
88 #define SSH2_MSG_GLOBAL_REQUEST 80 /* 0x50 */
89 #define SSH2_MSG_REQUEST_SUCCESS 81 /* 0x51 */
90 #define SSH2_MSG_REQUEST_FAILURE 82 /* 0x52 */
91 #define SSH2_MSG_CHANNEL_OPEN 90 /* 0x5a */
92 #define SSH2_MSG_CHANNEL_OPEN_CONFIRMATION 91 /* 0x5b */
93 #define SSH2_MSG_CHANNEL_OPEN_FAILURE 92 /* 0x5c */
94 #define SSH2_MSG_CHANNEL_WINDOW_ADJUST 93 /* 0x5d */
95 #define SSH2_MSG_CHANNEL_DATA 94 /* 0x5e */
96 #define SSH2_MSG_CHANNEL_EXTENDED_DATA 95 /* 0x5f */
97 #define SSH2_MSG_CHANNEL_EOF 96 /* 0x60 */
98 #define SSH2_MSG_CHANNEL_CLOSE 97 /* 0x61 */
99 #define SSH2_MSG_CHANNEL_REQUEST 98 /* 0x62 */
100 #define SSH2_MSG_CHANNEL_SUCCESS 99 /* 0x63 */
101 #define SSH2_MSG_CHANNEL_FAILURE 100 /* 0x64 */
102
103 /*
104 * Packet type contexts, so that ssh2_pkt_type can correctly decode
105 * the ambiguous type numbers back into the correct type strings.
106 */
107 #define SSH2_PKTCTX_DHGROUP1 0x0001
108 #define SSH2_PKTCTX_DHGEX 0x0002
109 #define SSH2_PKTCTX_PUBLICKEY 0x0010
110 #define SSH2_PKTCTX_PASSWORD 0x0020
111 #define SSH2_PKTCTX_KBDINTER 0x0040
112 #define SSH2_PKTCTX_AUTH_MASK 0x00F0
113
114 #define SSH2_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT 1 /* 0x1 */
115 #define SSH2_DISCONNECT_PROTOCOL_ERROR 2 /* 0x2 */
116 #define SSH2_DISCONNECT_KEY_EXCHANGE_FAILED 3 /* 0x3 */
117 #define SSH2_DISCONNECT_HOST_AUTHENTICATION_FAILED 4 /* 0x4 */
118 #define SSH2_DISCONNECT_MAC_ERROR 5 /* 0x5 */
119 #define SSH2_DISCONNECT_COMPRESSION_ERROR 6 /* 0x6 */
120 #define SSH2_DISCONNECT_SERVICE_NOT_AVAILABLE 7 /* 0x7 */
121 #define SSH2_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED 8 /* 0x8 */
122 #define SSH2_DISCONNECT_HOST_KEY_NOT_VERIFIABLE 9 /* 0x9 */
123 #define SSH2_DISCONNECT_CONNECTION_LOST 10 /* 0xa */
124 #define SSH2_DISCONNECT_BY_APPLICATION 11 /* 0xb */
125 #define SSH2_DISCONNECT_TOO_MANY_CONNECTIONS 12 /* 0xc */
126 #define SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER 13 /* 0xd */
127 #define SSH2_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE 14 /* 0xe */
128 #define SSH2_DISCONNECT_ILLEGAL_USER_NAME 15 /* 0xf */
129
130 static const char *const ssh2_disconnect_reasons[] = {
131 NULL,
132 "SSH_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT",
133 "SSH_DISCONNECT_PROTOCOL_ERROR",
134 "SSH_DISCONNECT_KEY_EXCHANGE_FAILED",
135 "SSH_DISCONNECT_HOST_AUTHENTICATION_FAILED",
136 "SSH_DISCONNECT_MAC_ERROR",
137 "SSH_DISCONNECT_COMPRESSION_ERROR",
138 "SSH_DISCONNECT_SERVICE_NOT_AVAILABLE",
139 "SSH_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED",
140 "SSH_DISCONNECT_HOST_KEY_NOT_VERIFIABLE",
141 "SSH_DISCONNECT_CONNECTION_LOST",
142 "SSH_DISCONNECT_BY_APPLICATION",
143 "SSH_DISCONNECT_TOO_MANY_CONNECTIONS",
144 "SSH_DISCONNECT_AUTH_CANCELLED_BY_USER",
145 "SSH_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE",
146 "SSH_DISCONNECT_ILLEGAL_USER_NAME",
147 };
148
149 #define SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED 1 /* 0x1 */
150 #define SSH2_OPEN_CONNECT_FAILED 2 /* 0x2 */
151 #define SSH2_OPEN_UNKNOWN_CHANNEL_TYPE 3 /* 0x3 */
152 #define SSH2_OPEN_RESOURCE_SHORTAGE 4 /* 0x4 */
153
154 #define SSH2_EXTENDED_DATA_STDERR 1 /* 0x1 */
155
156 /*
157 * Various remote-bug flags.
158 */
159 #define BUG_CHOKES_ON_SSH1_IGNORE 1
160 #define BUG_SSH2_HMAC 2
161 #define BUG_NEEDS_SSH1_PLAIN_PASSWORD 4
162 #define BUG_CHOKES_ON_RSA 8
163 #define BUG_SSH2_RSA_PADDING 16
164 #define BUG_SSH2_DERIVEKEY 32
165 #define BUG_SSH2_DH_GEX 64
166 #define BUG_SSH2_PK_SESSIONID 128
167
168 #define translate(x) if (type == x) return #x
169 #define translatec(x,ctx) if (type == x && (pkt_ctx & ctx)) return #x
170 static char *ssh1_pkt_type(int type)
171 {
172 translate(SSH1_MSG_DISCONNECT);
173 translate(SSH1_SMSG_PUBLIC_KEY);
174 translate(SSH1_CMSG_SESSION_KEY);
175 translate(SSH1_CMSG_USER);
176 translate(SSH1_CMSG_AUTH_RSA);
177 translate(SSH1_SMSG_AUTH_RSA_CHALLENGE);
178 translate(SSH1_CMSG_AUTH_RSA_RESPONSE);
179 translate(SSH1_CMSG_AUTH_PASSWORD);
180 translate(SSH1_CMSG_REQUEST_PTY);
181 translate(SSH1_CMSG_WINDOW_SIZE);
182 translate(SSH1_CMSG_EXEC_SHELL);
183 translate(SSH1_CMSG_EXEC_CMD);
184 translate(SSH1_SMSG_SUCCESS);
185 translate(SSH1_SMSG_FAILURE);
186 translate(SSH1_CMSG_STDIN_DATA);
187 translate(SSH1_SMSG_STDOUT_DATA);
188 translate(SSH1_SMSG_STDERR_DATA);
189 translate(SSH1_CMSG_EOF);
190 translate(SSH1_SMSG_EXIT_STATUS);
191 translate(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION);
192 translate(SSH1_MSG_CHANNEL_OPEN_FAILURE);
193 translate(SSH1_MSG_CHANNEL_DATA);
194 translate(SSH1_MSG_CHANNEL_CLOSE);
195 translate(SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION);
196 translate(SSH1_SMSG_X11_OPEN);
197 translate(SSH1_CMSG_PORT_FORWARD_REQUEST);
198 translate(SSH1_MSG_PORT_OPEN);
199 translate(SSH1_CMSG_AGENT_REQUEST_FORWARDING);
200 translate(SSH1_SMSG_AGENT_OPEN);
201 translate(SSH1_MSG_IGNORE);
202 translate(SSH1_CMSG_EXIT_CONFIRMATION);
203 translate(SSH1_CMSG_X11_REQUEST_FORWARDING);
204 translate(SSH1_CMSG_AUTH_RHOSTS_RSA);
205 translate(SSH1_MSG_DEBUG);
206 translate(SSH1_CMSG_REQUEST_COMPRESSION);
207 translate(SSH1_CMSG_AUTH_TIS);
208 translate(SSH1_SMSG_AUTH_TIS_CHALLENGE);
209 translate(SSH1_CMSG_AUTH_TIS_RESPONSE);
210 translate(SSH1_CMSG_AUTH_CCARD);
211 translate(SSH1_SMSG_AUTH_CCARD_CHALLENGE);
212 translate(SSH1_CMSG_AUTH_CCARD_RESPONSE);
213 return "unknown";
214 }
215 static char *ssh2_pkt_type(int pkt_ctx, int type)
216 {
217 translate(SSH2_MSG_DISCONNECT);
218 translate(SSH2_MSG_IGNORE);
219 translate(SSH2_MSG_UNIMPLEMENTED);
220 translate(SSH2_MSG_DEBUG);
221 translate(SSH2_MSG_SERVICE_REQUEST);
222 translate(SSH2_MSG_SERVICE_ACCEPT);
223 translate(SSH2_MSG_KEXINIT);
224 translate(SSH2_MSG_NEWKEYS);
225 translatec(SSH2_MSG_KEXDH_INIT, SSH2_PKTCTX_DHGROUP1);
226 translatec(SSH2_MSG_KEXDH_REPLY, SSH2_PKTCTX_DHGROUP1);
227 translatec(SSH2_MSG_KEX_DH_GEX_REQUEST, SSH2_PKTCTX_DHGEX);
228 translatec(SSH2_MSG_KEX_DH_GEX_GROUP, SSH2_PKTCTX_DHGEX);
229 translatec(SSH2_MSG_KEX_DH_GEX_INIT, SSH2_PKTCTX_DHGEX);
230 translatec(SSH2_MSG_KEX_DH_GEX_REPLY, SSH2_PKTCTX_DHGEX);
231 translate(SSH2_MSG_USERAUTH_REQUEST);
232 translate(SSH2_MSG_USERAUTH_FAILURE);
233 translate(SSH2_MSG_USERAUTH_SUCCESS);
234 translate(SSH2_MSG_USERAUTH_BANNER);
235 translatec(SSH2_MSG_USERAUTH_PK_OK, SSH2_PKTCTX_PUBLICKEY);
236 translatec(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, SSH2_PKTCTX_PASSWORD);
237 translatec(SSH2_MSG_USERAUTH_INFO_REQUEST, SSH2_PKTCTX_KBDINTER);
238 translatec(SSH2_MSG_USERAUTH_INFO_RESPONSE, SSH2_PKTCTX_KBDINTER);
239 translate(SSH2_MSG_GLOBAL_REQUEST);
240 translate(SSH2_MSG_REQUEST_SUCCESS);
241 translate(SSH2_MSG_REQUEST_FAILURE);
242 translate(SSH2_MSG_CHANNEL_OPEN);
243 translate(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
244 translate(SSH2_MSG_CHANNEL_OPEN_FAILURE);
245 translate(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
246 translate(SSH2_MSG_CHANNEL_DATA);
247 translate(SSH2_MSG_CHANNEL_EXTENDED_DATA);
248 translate(SSH2_MSG_CHANNEL_EOF);
249 translate(SSH2_MSG_CHANNEL_CLOSE);
250 translate(SSH2_MSG_CHANNEL_REQUEST);
251 translate(SSH2_MSG_CHANNEL_SUCCESS);
252 translate(SSH2_MSG_CHANNEL_FAILURE);
253 return "unknown";
254 }
255 #undef translate
256 #undef translatec
257
258 #define GET_32BIT(cp) \
259 (((unsigned long)(unsigned char)(cp)[0] << 24) | \
260 ((unsigned long)(unsigned char)(cp)[1] << 16) | \
261 ((unsigned long)(unsigned char)(cp)[2] << 8) | \
262 ((unsigned long)(unsigned char)(cp)[3]))
263
264 #define PUT_32BIT(cp, value) { \
265 (cp)[0] = (unsigned char)((value) >> 24); \
266 (cp)[1] = (unsigned char)((value) >> 16); \
267 (cp)[2] = (unsigned char)((value) >> 8); \
268 (cp)[3] = (unsigned char)(value); }
269
270 enum { PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR, PKT_BIGNUM };
271
272 /*
273 * Coroutine mechanics for the sillier bits of the code. If these
274 * macros look impenetrable to you, you might find it helpful to
275 * read
276 *
277 * http://www.chiark.greenend.org.uk/~sgtatham/coroutines.html
278 *
279 * which explains the theory behind these macros.
280 *
281 * In particular, if you are getting `case expression not constant'
282 * errors when building with MS Visual Studio, this is because MS's
283 * Edit and Continue debugging feature causes their compiler to
284 * violate ANSI C. To disable Edit and Continue debugging:
285 *
286 * - right-click ssh.c in the FileView
287 * - click Settings
288 * - select the C/C++ tab and the General category
289 * - under `Debug info:', select anything _other_ than `Program
290 * Database for Edit and Continue'.
291 */
292 #define crBegin(v) { int *crLine = &v; switch(v) { case 0:;
293 #define crState(t) \
294 struct t *s; \
295 if (!ssh->t) ssh->t = snew(struct t); \
296 s = ssh->t;
297 #define crFinish(z) } *crLine = 0; return (z); }
298 #define crFinishV } *crLine = 0; return; }
299 #define crReturn(z) \
300 do {\
301 *crLine =__LINE__; return (z); case __LINE__:;\
302 } while (0)
303 #define crReturnV \
304 do {\
305 *crLine=__LINE__; return; case __LINE__:;\
306 } while (0)
307 #define crStop(z) do{ *crLine = 0; return (z); }while(0)
308 #define crStopV do{ *crLine = 0; return; }while(0)
309 #define crWaitUntil(c) do { crReturn(0); } while (!(c))
310 #define crWaitUntilV(c) do { crReturnV; } while (!(c))
311
312 typedef struct ssh_tag *Ssh;
313
314 static void ssh2_pkt_init(Ssh, int pkt_type);
315 static void ssh2_pkt_addbool(Ssh, unsigned char value);
316 static void ssh2_pkt_adduint32(Ssh, unsigned long value);
317 static void ssh2_pkt_addstring_start(Ssh);
318 static void ssh2_pkt_addstring_str(Ssh, char *data);
319 static void ssh2_pkt_addstring_data(Ssh, char *data, int len);
320 static void ssh2_pkt_addstring(Ssh, char *data);
321 static unsigned char *ssh2_mpint_fmt(Bignum b, int *len);
322 static void ssh2_pkt_addmp(Ssh, Bignum b);
323 static int ssh2_pkt_construct(Ssh);
324 static void ssh2_pkt_send(Ssh);
325 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 crWaitUntil(ispkt);
2539
2540 if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
2541 bombout(("Encryption not successfully enabled"));
2542 crStop(0);
2543 }
2544
2545 logevent("Successfully started encryption");
2546
2547 fflush(stdout);
2548 {
2549 if ((flags & FLAG_INTERACTIVE) && !*ssh->cfg.username) {
2550 if (ssh_get_line && !ssh_getline_pw_only) {
2551 if (!ssh_get_line("login as: ",
2552 s->username, sizeof(s->username), FALSE)) {
2553 /*
2554 * get_line failed to get a username.
2555 * Terminate.
2556 */
2557 logevent("No username provided. Abandoning session.");
2558 ssh_closing((Plug)ssh, NULL, 0, 0);
2559 crStop(1);
2560 }
2561 } else {
2562 int ret; /* need not be kept over crReturn */
2563 c_write_str(ssh, "login as: ");
2564 ssh->send_ok = 1;
2565
2566 setup_userpass_input(ssh, s->username, sizeof(s->username), 1);
2567 do {
2568 crWaitUntil(!ispkt);
2569 ret = process_userpass_input(ssh, in, inlen);
2570 } while (ret == 0);
2571 if (ret < 0)
2572 cleanup_exit(0);
2573 c_write_str(ssh, "\r\n");
2574 }
2575 } else {
2576 strncpy(s->username, ssh->cfg.username, sizeof(s->username));
2577 s->username[sizeof(s->username)-1] = '\0';
2578 }
2579
2580 send_packet(ssh, SSH1_CMSG_USER, PKT_STR, s->username, PKT_END);
2581 {
2582 char userlog[22 + sizeof(s->username)];
2583 sprintf(userlog, "Sent username \"%s\"", s->username);
2584 logevent(userlog);
2585 if (flags & FLAG_INTERACTIVE &&
2586 (!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) {
2587 strcat(userlog, "\r\n");
2588 c_write_str(ssh, userlog);
2589 }
2590 }
2591 }
2592
2593 crWaitUntil(ispkt);
2594
2595 if ((ssh->remote_bugs & BUG_CHOKES_ON_RSA)) {
2596 /* We must not attempt PK auth. Pretend we've already tried it. */
2597 s->tried_publickey = s->tried_agent = 1;
2598 } else {
2599 s->tried_publickey = s->tried_agent = 0;
2600 }
2601 s->tis_auth_refused = s->ccard_auth_refused = 0;
2602 /* Load the public half of ssh->cfg.keyfile so we notice if it's in Pageant */
2603 if (!filename_is_null(ssh->cfg.keyfile)) {
2604 if (!rsakey_pubblob(&ssh->cfg.keyfile,
2605 &s->publickey_blob, &s->publickey_bloblen, NULL))
2606 s->publickey_blob = NULL;
2607 } else
2608 s->publickey_blob = NULL;
2609
2610 while (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2611 s->pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
2612
2613 if (agent_exists() && !s->tried_agent) {
2614 /*
2615 * Attempt RSA authentication using Pageant.
2616 */
2617 void *r;
2618
2619 s->authed = FALSE;
2620 s->tried_agent = 1;
2621 logevent("Pageant is running. Requesting keys.");
2622
2623 /* Request the keys held by the agent. */
2624 PUT_32BIT(s->request, 1);
2625 s->request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES;
2626 if (!agent_query(s->request, 5, &r, &s->responselen,
2627 ssh_agent_callback, ssh)) {
2628 do {
2629 crReturn(0);
2630 if (ispkt) {
2631 bombout(("Unexpected data from server while waiting"
2632 " for agent response"));
2633 crStop(0);
2634 }
2635 } while (ispkt || inlen > 0);
2636 r = ssh->agent_response;
2637 s->responselen = ssh->agent_response_len;
2638 }
2639 s->response = (unsigned char *) r;
2640 if (s->response && s->responselen >= 5 &&
2641 s->response[4] == SSH1_AGENT_RSA_IDENTITIES_ANSWER) {
2642 s->p = s->response + 5;
2643 s->nkeys = GET_32BIT(s->p);
2644 s->p += 4;
2645 {
2646 char buf[64];
2647 sprintf(buf, "Pageant has %d SSH1 keys", s->nkeys);
2648 logevent(buf);
2649 }
2650 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
2651 {
2652 char buf[64];
2653 sprintf(buf, "Trying Pageant key #%d", s->keyi);
2654 logevent(buf);
2655 }
2656 if (s->publickey_blob &&
2657 !memcmp(s->p, s->publickey_blob,
2658 s->publickey_bloblen)) {
2659 logevent("This key matches configured key file");
2660 s->tried_publickey = 1;
2661 }
2662 s->p += 4;
2663 s->p += ssh1_read_bignum(s->p, &s->key.exponent);
2664 s->p += ssh1_read_bignum(s->p, &s->key.modulus);
2665 s->commentlen = GET_32BIT(s->p);
2666 s->p += 4;
2667 s->commentp = (char *)s->p;
2668 s->p += s->commentlen;
2669 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
2670 PKT_BIGNUM, s->key.modulus, PKT_END);
2671 crWaitUntil(ispkt);
2672 if (ssh->pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
2673 logevent("Key refused");
2674 continue;
2675 }
2676 logevent("Received RSA challenge");
2677 ssh1_read_bignum(ssh->pktin.body, &s->challenge);
2678 {
2679 char *agentreq, *q, *ret;
2680 void *vret;
2681 int len, retlen;
2682 len = 1 + 4; /* message type, bit count */
2683 len += ssh1_bignum_length(s->key.exponent);
2684 len += ssh1_bignum_length(s->key.modulus);
2685 len += ssh1_bignum_length(s->challenge);
2686 len += 16; /* session id */
2687 len += 4; /* response format */
2688 agentreq = snewn(4 + len, char);
2689 PUT_32BIT(agentreq, len);
2690 q = agentreq + 4;
2691 *q++ = SSH1_AGENTC_RSA_CHALLENGE;
2692 PUT_32BIT(q, bignum_bitcount(s->key.modulus));
2693 q += 4;
2694 q += ssh1_write_bignum(q, s->key.exponent);
2695 q += ssh1_write_bignum(q, s->key.modulus);
2696 q += ssh1_write_bignum(q, s->challenge);
2697 memcpy(q, s->session_id, 16);
2698 q += 16;
2699 PUT_32BIT(q, 1); /* response format */
2700 if (!agent_query(agentreq, len + 4, &vret, &retlen,
2701 ssh_agent_callback, ssh)) {
2702 sfree(agentreq);
2703 do {
2704 crReturn(0);
2705 if (ispkt) {
2706 bombout(("Unexpected data from server"
2707 " while waiting for agent"
2708 " response"));
2709 crStop(0);
2710 }
2711 } while (ispkt || inlen > 0);
2712 vret = ssh->agent_response;
2713 retlen = ssh->agent_response_len;
2714 } else
2715 sfree(agentreq);
2716 ret = vret;
2717 if (ret) {
2718 if (ret[4] == SSH1_AGENT_RSA_RESPONSE) {
2719 logevent("Sending Pageant's response");
2720 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
2721 PKT_DATA, ret + 5, 16,
2722 PKT_END);
2723 sfree(ret);
2724 crWaitUntil(ispkt);
2725 if (ssh->pktin.type == SSH1_SMSG_SUCCESS) {
2726 logevent
2727 ("Pageant's response accepted");
2728 if (flags & FLAG_VERBOSE) {
2729 c_write_str(ssh, "Authenticated using"
2730 " RSA key \"");
2731 c_write(ssh, s->commentp,
2732 s->commentlen);
2733 c_write_str(ssh, "\" from agent\r\n");
2734 }
2735 s->authed = TRUE;
2736 } else
2737 logevent
2738 ("Pageant's response not accepted");
2739 } else {
2740 logevent
2741 ("Pageant failed to answer challenge");
2742 sfree(ret);
2743 }
2744 } else {
2745 logevent("No reply received from Pageant");
2746 }
2747 }
2748 freebn(s->key.exponent);
2749 freebn(s->key.modulus);
2750 freebn(s->challenge);
2751 if (s->authed)
2752 break;
2753 }
2754 }
2755 if (s->authed)
2756 break;
2757 }
2758 if (!filename_is_null(ssh->cfg.keyfile) && !s->tried_publickey)
2759 s->pwpkt_type = SSH1_CMSG_AUTH_RSA;
2760
2761 if (ssh->cfg.try_tis_auth &&
2762 (s->supported_auths_mask & (1 << SSH1_AUTH_TIS)) &&
2763 !s->tis_auth_refused) {
2764 s->pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
2765 logevent("Requested TIS authentication");
2766 send_packet(ssh, SSH1_CMSG_AUTH_TIS, PKT_END);
2767 crWaitUntil(ispkt);
2768 if (ssh->pktin.type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
2769 logevent("TIS authentication declined");
2770 if (flags & FLAG_INTERACTIVE)
2771 c_write_str(ssh, "TIS authentication refused.\r\n");
2772 s->tis_auth_refused = 1;
2773 continue;
2774 } else {
2775 int challengelen = GET_32BIT(ssh->pktin.body);
2776 logevent("Received TIS challenge");
2777 if (challengelen > sizeof(s->prompt) - 1)
2778 challengelen = sizeof(s->prompt) - 1;/* prevent overrun */
2779 memcpy(s->prompt, ssh->pktin.body + 4, challengelen);
2780 /* Prompt heuristic comes from OpenSSH */
2781 strncpy(s->prompt + challengelen,
2782 memchr(s->prompt, '\n', challengelen) ?
2783 "": "\r\nResponse: ",
2784 (sizeof s->prompt) - challengelen);
2785 s->prompt[(sizeof s->prompt) - 1] = '\0';
2786 }
2787 }
2788 if (ssh->cfg.try_tis_auth &&
2789 (s->supported_auths_mask & (1 << SSH1_AUTH_CCARD)) &&
2790 !s->ccard_auth_refused) {
2791 s->pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE;
2792 logevent("Requested CryptoCard authentication");
2793 send_packet(ssh, SSH1_CMSG_AUTH_CCARD, PKT_END);
2794 crWaitUntil(ispkt);
2795 if (ssh->pktin.type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
2796 logevent("CryptoCard authentication declined");
2797 c_write_str(ssh, "CryptoCard authentication refused.\r\n");
2798 s->ccard_auth_refused = 1;
2799 continue;
2800 } else {
2801 int challengelen = GET_32BIT(ssh->pktin.body);
2802 logevent("Received CryptoCard challenge");
2803 if (challengelen > sizeof(s->prompt) - 1)
2804 challengelen = sizeof(s->prompt) - 1;/* prevent overrun */
2805 memcpy(s->prompt, ssh->pktin.body + 4, challengelen);
2806 strncpy(s->prompt + challengelen,
2807 memchr(s->prompt, '\n', challengelen) ?
2808 "" : "\r\nResponse: ",
2809 sizeof(s->prompt) - challengelen);
2810 s->prompt[sizeof(s->prompt) - 1] = '\0';
2811 }
2812 }
2813 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
2814 sprintf(s->prompt, "%.90s@%.90s's password: ",
2815 s->username, ssh->savedhost);
2816 }
2817 if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) {
2818 char *comment = NULL;
2819 int type;
2820 char msgbuf[256];
2821 if (flags & FLAG_VERBOSE)
2822 c_write_str(ssh, "Trying public key authentication.\r\n");
2823 logeventf(ssh, "Trying public key \"%s\"",
2824 filename_to_str(&ssh->cfg.keyfile));
2825 type = key_type(&ssh->cfg.keyfile);
2826 if (type != SSH_KEYTYPE_SSH1) {
2827 sprintf(msgbuf, "Key is of wrong type (%s)",
2828 key_type_to_str(type));
2829 logevent(msgbuf);
2830 c_write_str(ssh, msgbuf);
2831 c_write_str(ssh, "\r\n");
2832 s->tried_publickey = 1;
2833 continue;
2834 }
2835 if (!rsakey_encrypted(&ssh->cfg.keyfile, &comment)) {
2836 if (flags & FLAG_VERBOSE)
2837 c_write_str(ssh, "No passphrase required.\r\n");
2838 goto tryauth;
2839 }
2840 sprintf(s->prompt, "Passphrase for key \"%.100s\": ", comment);
2841 sfree(comment);
2842 }
2843
2844 /*
2845 * Show password prompt, having first obtained it via a TIS
2846 * or CryptoCard exchange if we're doing TIS or CryptoCard
2847 * authentication.
2848 */
2849 if (ssh_get_line) {
2850 if (!ssh_get_line(s->prompt, s->password,
2851 sizeof(s->password), TRUE)) {
2852 /*
2853 * get_line failed to get a password (for example
2854 * because one was supplied on the command line
2855 * which has already failed to work). Terminate.
2856 */
2857 send_packet(ssh, SSH1_MSG_DISCONNECT,
2858 PKT_STR, "No more passwords available to try",
2859 PKT_END);
2860 logevent("Unable to authenticate");
2861 connection_fatal(ssh->frontend, "Unable to authenticate");
2862 ssh_closing((Plug)ssh, NULL, 0, 0);
2863 crStop(1);
2864 }
2865 } else {
2866 /* Prompt may have come from server. We've munged it a bit, so
2867 * we know it to be zero-terminated at least once. */
2868 int ret; /* need not be saved over crReturn */
2869 c_write_untrusted(ssh, s->prompt, strlen(s->prompt));
2870 s->pos = 0;
2871
2872 setup_userpass_input(ssh, s->password, sizeof(s->password), 0);
2873 do {
2874 crWaitUntil(!ispkt);
2875 ret = process_userpass_input(ssh, in, inlen);
2876 } while (ret == 0);
2877 if (ret < 0)
2878 cleanup_exit(0);
2879 c_write_str(ssh, "\r\n");
2880 }
2881
2882 tryauth:
2883 if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) {
2884 /*
2885 * Try public key authentication with the specified
2886 * key file.
2887 */
2888 s->tried_publickey = 1;
2889
2890 {
2891 const char *error = NULL;
2892 int ret = loadrsakey(&ssh->cfg.keyfile, &s->key, s->password,
2893 &error);
2894 if (ret == 0) {
2895 c_write_str(ssh, "Couldn't load private key from ");
2896 c_write_str(ssh, filename_to_str(&ssh->cfg.keyfile));
2897 c_write_str(ssh, " (");
2898 c_write_str(ssh, error);
2899 c_write_str(ssh, ").\r\n");
2900 continue; /* go and try password */
2901 }
2902 if (ret == -1) {
2903 c_write_str(ssh, "Wrong passphrase.\r\n");
2904 s->tried_publickey = 0;
2905 continue; /* try again */
2906 }
2907 }
2908
2909 /*
2910 * Send a public key attempt.
2911 */
2912 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
2913 PKT_BIGNUM, s->key.modulus, PKT_END);
2914
2915 crWaitUntil(ispkt);
2916 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2917 c_write_str(ssh, "Server refused our public key.\r\n");
2918 continue; /* go and try password */
2919 }
2920 if (ssh->pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
2921 bombout(("Bizarre response to offer of public key"));
2922 crStop(0);
2923 }
2924
2925 {
2926 int i;
2927 unsigned char buffer[32];
2928 Bignum challenge, response;
2929
2930 ssh1_read_bignum(ssh->pktin.body, &challenge);
2931 response = rsadecrypt(challenge, &s->key);
2932 freebn(s->key.private_exponent);/* burn the evidence */
2933
2934 for (i = 0; i < 32; i++) {
2935 buffer[i] = bignum_byte(response, 31 - i);
2936 }
2937
2938 MD5Init(&md5c);
2939 MD5Update(&md5c, buffer, 32);
2940 MD5Update(&md5c, s->session_id, 16);
2941 MD5Final(buffer, &md5c);
2942
2943 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
2944 PKT_DATA, buffer, 16, PKT_END);
2945
2946 freebn(challenge);
2947 freebn(response);
2948 }
2949
2950 crWaitUntil(ispkt);
2951 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2952 if (flags & FLAG_VERBOSE)
2953 c_write_str(ssh, "Failed to authenticate with"
2954 " our public key.\r\n");
2955 continue; /* go and try password */
2956 } else if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
2957 bombout(("Bizarre response to RSA authentication response"));
2958 crStop(0);
2959 }
2960
2961 break; /* we're through! */
2962 } else {
2963 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
2964 /*
2965 * Defence against traffic analysis: we send a
2966 * whole bunch of packets containing strings of
2967 * different lengths. One of these strings is the
2968 * password, in a SSH1_CMSG_AUTH_PASSWORD packet.
2969 * The others are all random data in
2970 * SSH1_MSG_IGNORE packets. This way a passive
2971 * listener can't tell which is the password, and
2972 * hence can't deduce the password length.
2973 *
2974 * Anybody with a password length greater than 16
2975 * bytes is going to have enough entropy in their
2976 * password that a listener won't find it _that_
2977 * much help to know how long it is. So what we'll
2978 * do is:
2979 *
2980 * - if password length < 16, we send 15 packets
2981 * containing string lengths 1 through 15
2982 *
2983 * - otherwise, we let N be the nearest multiple
2984 * of 8 below the password length, and send 8
2985 * packets containing string lengths N through
2986 * N+7. This won't obscure the order of
2987 * magnitude of the password length, but it will
2988 * introduce a bit of extra uncertainty.
2989 *
2990 * A few servers (the old 1.2.18 through 1.2.22)
2991 * can't deal with SSH1_MSG_IGNORE. For these
2992 * servers, we need an alternative defence. We make
2993 * use of the fact that the password is interpreted
2994 * as a C string: so we can append a NUL, then some
2995 * random data.
2996 *
2997 * One server (a Cisco one) can deal with neither
2998 * SSH1_MSG_IGNORE _nor_ a padded password string.
2999 * For this server we are left with no defences
3000 * against password length sniffing.
3001 */
3002 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE)) {
3003 /*
3004 * The server can deal with SSH1_MSG_IGNORE, so
3005 * we can use the primary defence.
3006 */
3007 int bottom, top, pwlen, i;
3008 char *randomstr;
3009
3010 pwlen = strlen(s->password);
3011 if (pwlen < 16) {
3012 bottom = 0; /* zero length passwords are OK! :-) */
3013 top = 15;
3014 } else {
3015 bottom = pwlen & ~7;
3016 top = bottom + 7;
3017 }
3018
3019 assert(pwlen >= bottom && pwlen <= top);
3020
3021 randomstr = snewn(top + 1, char);
3022
3023 for (i = bottom; i <= top; i++) {
3024 if (i == pwlen)
3025 defer_packet(ssh, s->pwpkt_type,
3026 PKT_STR, s->password, PKT_END);
3027 else {
3028 for (j = 0; j < i; j++) {
3029 do {
3030 randomstr[j] = random_byte();
3031 } while (randomstr[j] == '\0');
3032 }
3033 randomstr[i] = '\0';
3034 defer_packet(ssh, SSH1_MSG_IGNORE,
3035 PKT_STR, randomstr, PKT_END);
3036 }
3037 }
3038 logevent("Sending password with camouflage packets");
3039 ssh_pkt_defersend(ssh);
3040 }
3041 else if (!(ssh->remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) {
3042 /*
3043 * The server can't deal with SSH1_MSG_IGNORE
3044 * but can deal with padded passwords, so we
3045 * can use the secondary defence.
3046 */
3047 char string[64];
3048 char *ss;
3049 int len;
3050
3051 len = strlen(s->password);
3052 if (len < sizeof(string)) {
3053 ss = string;
3054 strcpy(string, s->password);
3055 len++; /* cover the zero byte */
3056 while (len < sizeof(string)) {
3057 string[len++] = (char) random_byte();
3058 }
3059 } else {
3060 ss = s->password;
3061 }
3062 logevent("Sending length-padded password");
3063 send_packet(ssh, s->pwpkt_type, PKT_INT, len,
3064 PKT_DATA, ss, len, PKT_END);
3065 } else {
3066 /*
3067 * The server has _both_
3068 * BUG_CHOKES_ON_SSH1_IGNORE and
3069 * BUG_NEEDS_SSH1_PLAIN_PASSWORD. There is
3070 * therefore nothing we can do.
3071 */
3072 int len;
3073 len = strlen(s->password);
3074 logevent("Sending unpadded password");
3075 send_packet(ssh, s->pwpkt_type, PKT_INT, len,
3076 PKT_DATA, s->password, len, PKT_END);
3077 }
3078 } else {
3079 send_packet(ssh, s->pwpkt_type, PKT_STR, s->password, PKT_END);
3080 }
3081 }
3082 logevent("Sent password");
3083 memset(s->password, 0, strlen(s->password));
3084 crWaitUntil(ispkt);
3085 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3086 if (flags & FLAG_VERBOSE)
3087 c_write_str(ssh, "Access denied\r\n");
3088 logevent("Authentication refused");
3089 } else if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
3090 bombout(("Strange packet received, type %d", ssh->pktin.type));
3091 crStop(0);
3092 }
3093 }
3094
3095 logevent("Authentication successful");
3096
3097 crFinish(1);
3098 }
3099
3100 void sshfwd_close(struct ssh_channel *c)
3101 {
3102 Ssh ssh = c->ssh;
3103
3104 if (ssh->state != SSH_STATE_SESSION) {
3105 assert(ssh->state == SSH_STATE_CLOSED);
3106 return;
3107 }
3108
3109 if (c && !c->closes) {
3110 /*
3111 * If the channel's remoteid is -1, we have sent
3112 * CHANNEL_OPEN for this channel, but it hasn't even been
3113 * acknowledged by the server. So we must set a close flag
3114 * on it now, and then when the server acks the channel
3115 * open, we can close it then.
3116 */
3117 if (((int)c->remoteid) != -1) {
3118 if (ssh->version == 1) {
3119 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid,
3120 PKT_END);
3121 } else {
3122 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
3123 ssh2_pkt_adduint32(ssh, c->remoteid);
3124 ssh2_pkt_send(ssh);
3125 }
3126 }
3127 c->closes = 1; /* sent MSG_CLOSE */
3128 if (c->type == CHAN_X11) {
3129 c->u.x11.s = NULL;
3130 logevent("Forwarded X11 connection terminated");
3131 } else if (c->type == CHAN_SOCKDATA ||
3132 c->type == CHAN_SOCKDATA_DORMANT) {
3133 c->u.pfd.s = NULL;
3134 logevent("Forwarded port closed");
3135 }
3136 }
3137 }
3138
3139 int sshfwd_write(struct ssh_channel *c, char *buf, int len)
3140 {
3141 Ssh ssh = c->ssh;
3142
3143 if (ssh->state != SSH_STATE_SESSION) {
3144 assert(ssh->state == SSH_STATE_CLOSED);
3145 return 0;
3146 }
3147
3148 if (ssh->version == 1) {
3149 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
3150 PKT_INT, c->remoteid,
3151 PKT_INT, len, PKT_DATA, buf, len, PKT_END);
3152 /*
3153 * In SSH1 we can return 0 here - implying that forwarded
3154 * connections are never individually throttled - because
3155 * the only circumstance that can cause throttling will be
3156 * the whole SSH connection backing up, in which case
3157 * _everything_ will be throttled as a whole.
3158 */
3159 return 0;
3160 } else {
3161 ssh2_add_channel_data(c, buf, len);
3162 return ssh2_try_send(c);
3163 }
3164 }
3165
3166 void sshfwd_unthrottle(struct ssh_channel *c, int bufsize)
3167 {
3168 Ssh ssh = c->ssh;
3169
3170 if (ssh->state != SSH_STATE_SESSION) {
3171 assert(ssh->state == SSH_STATE_CLOSED);
3172 return;
3173 }
3174
3175 if (ssh->version == 1) {
3176 if (c->v.v1.throttling && bufsize < SSH1_BUFFER_LIMIT) {
3177 c->v.v1.throttling = 0;
3178 ssh1_throttle(ssh, -1);
3179 }
3180 } else {
3181 ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
3182 }
3183 }
3184
3185 static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
3186 {
3187 crBegin(ssh->ssh1_protocol_crstate);
3188
3189 random_init();
3190
3191 while (!do_ssh1_login(ssh, in, inlen, ispkt)) {
3192 crReturnV;
3193 }
3194 if (ssh->state == SSH_STATE_CLOSED)
3195 crReturnV;
3196
3197 if (ssh->cfg.agentfwd && agent_exists()) {
3198 logevent("Requesting agent forwarding");
3199 send_packet(ssh, SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END);
3200 do {
3201 crReturnV;
3202 } while (!ispkt);
3203 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3204 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3205 bombout(("Protocol confusion"));
3206 crStopV;
3207 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3208 logevent("Agent forwarding refused");
3209 } else {
3210 logevent("Agent forwarding enabled");
3211 ssh->agentfwd_enabled = TRUE;
3212 }
3213 }
3214
3215 if (ssh->cfg.x11_forward) {
3216 char proto[20], data[64];
3217 logevent("Requesting X11 forwarding");
3218 ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
3219 data, sizeof(data), ssh->cfg.x11_auth);
3220 x11_get_real_auth(ssh->x11auth, ssh->cfg.x11_display);
3221 if (ssh->v1_local_protoflags & SSH1_PROTOFLAG_SCREEN_NUMBER) {
3222 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
3223 PKT_STR, proto, PKT_STR, data,
3224 PKT_INT, x11_get_screen_number(ssh->cfg.x11_display),
3225 PKT_END);
3226 } else {
3227 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
3228 PKT_STR, proto, PKT_STR, data, PKT_END);
3229 }
3230 do {
3231 crReturnV;
3232 } while (!ispkt);
3233 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3234 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3235 bombout(("Protocol confusion"));
3236 crStopV;
3237 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3238 logevent("X11 forwarding refused");
3239 } else {
3240 logevent("X11 forwarding enabled");
3241 ssh->X11_fwd_enabled = TRUE;
3242 }
3243 }
3244
3245 {
3246 char type;
3247 int n;
3248 int sport,dport,sserv,dserv;
3249 char sports[256], dports[256], saddr[256], host[256];
3250
3251 ssh->rportfwds = newtree234(ssh_rportcmp_ssh1);
3252 /* Add port forwardings. */
3253 ssh->portfwd_strptr = ssh->cfg.portfwd;
3254 while (*ssh->portfwd_strptr) {
3255 type = *ssh->portfwd_strptr++;
3256 saddr[0] = '\0';
3257 n = 0;
3258 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != '\t') {
3259 if (*ssh->portfwd_strptr == ':') {
3260 /*
3261 * We've seen a colon in the middle of the
3262 * source port number. This means that
3263 * everything we've seen until now is the
3264 * source _address_, so we'll move it into
3265 * saddr and start sports from the beginning
3266 * again.
3267 */
3268 ssh->portfwd_strptr++;
3269 sports[n] = '\0';
3270 strcpy(saddr, sports);
3271 n = 0;
3272 }
3273 if (n < 255) sports[n++] = *ssh->portfwd_strptr++;
3274 }
3275 sports[n] = 0;
3276 if (type != 'D') {
3277 if (*ssh->portfwd_strptr == '\t')
3278 ssh->portfwd_strptr++;
3279 n = 0;
3280 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':') {
3281 if (n < 255) host[n++] = *ssh->portfwd_strptr++;
3282 }
3283 host[n] = 0;
3284 if (*ssh->portfwd_strptr == ':')
3285 ssh->portfwd_strptr++;
3286 n = 0;
3287 while (*ssh->portfwd_strptr) {
3288 if (n < 255) dports[n++] = *ssh->portfwd_strptr++;
3289 }
3290 dports[n] = 0;
3291 ssh->portfwd_strptr++;
3292 dport = atoi(dports);
3293 dserv = 0;
3294 if (dport == 0) {
3295 dserv = 1;
3296 dport = net_service_lookup(dports);
3297 if (!dport) {
3298 logeventf(ssh, "Service lookup failed for"
3299 " destination port \"%s\"", dports);
3300 }
3301 }
3302 } else {
3303 while (*ssh->portfwd_strptr) ssh->portfwd_strptr++;
3304 dport = dserv = -1;
3305 ssh->portfwd_strptr++; /* eat the NUL and move to next one */
3306 }
3307 sport = atoi(sports);
3308 sserv = 0;
3309 if (sport == 0) {
3310 sserv = 1;
3311 sport = net_service_lookup(sports);
3312 if (!sport) {
3313 logeventf(ssh, "Service lookup failed for source"
3314 " port \"%s\"", sports);
3315 }
3316 }
3317 if (sport && dport) {
3318 if (type == 'L') {
3319 pfd_addforward(host, dport, *saddr ? saddr : NULL,
3320 sport, ssh, &ssh->cfg);
3321 logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
3322 " forwarding to %s:%.*s%.*s%d%.*s",
3323 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
3324 (int)(*saddr?1:0), ":",
3325 (int)(sserv ? strlen(sports) : 0), sports,
3326 sserv, "(", sport, sserv, ")",
3327 host,
3328 (int)(dserv ? strlen(dports) : 0), dports,
3329 dserv, "(", dport, dserv, ")");
3330 } else if (type == 'D') {
3331 pfd_addforward(NULL, -1, *saddr ? saddr : NULL,
3332 sport, ssh, &ssh->cfg);
3333 logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
3334 " doing SOCKS dynamic forwarding",
3335 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
3336 (int)(*saddr?1:0), ":",
3337 (int)(sserv ? strlen(sports) : 0), sports,
3338 sserv, "(", sport, sserv, ")");
3339 } else {
3340 struct ssh_rportfwd *pf;
3341 pf = snew(struct ssh_rportfwd);
3342 strcpy(pf->dhost, host);
3343 pf->dport = dport;
3344 if (saddr) {
3345 logeventf(ssh,
3346 "SSH1 cannot handle source address spec \"%s:%d\"; ignoring",
3347 saddr, sport);
3348 }
3349 if (add234(ssh->rportfwds, pf) != pf) {
3350 logeventf(ssh,
3351 "Duplicate remote port forwarding to %s:%d",
3352 host, dport);
3353 sfree(pf);
3354 } else {
3355 logeventf(ssh, "Requesting remote port %.*s%.*s%d%.*s"
3356 " forward to %s:%.*s%.*s%d%.*s",
3357 (int)(sserv ? strlen(sports) : 0), sports,
3358 sserv, "(", sport, sserv, ")",
3359 host,
3360 (int)(dserv ? strlen(dports) : 0), dports,
3361 dserv, "(", dport, dserv, ")");
3362 send_packet(ssh, SSH1_CMSG_PORT_FORWARD_REQUEST,
3363 PKT_INT, sport,
3364 PKT_STR, host,
3365 PKT_INT, dport,
3366 PKT_END);
3367 do {
3368 crReturnV;
3369 } while (!ispkt);
3370 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3371 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3372 bombout(("Protocol confusion"));
3373 crStopV;
3374 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3375 c_write_str(ssh, "Server refused port"
3376 " forwarding\r\n");
3377 }
3378 logevent("Remote port forwarding enabled");
3379 }
3380 }
3381 }
3382 }
3383 }
3384
3385 if (!ssh->cfg.nopty) {
3386 send_packet(ssh, SSH1_CMSG_REQUEST_PTY,
3387 PKT_STR, ssh->cfg.termtype,
3388 PKT_INT, ssh->term_height,
3389 PKT_INT, ssh->term_width,
3390 PKT_INT, 0, PKT_INT, 0, PKT_CHAR, 0, PKT_END);
3391 ssh->state = SSH_STATE_INTERMED;
3392 do {
3393 crReturnV;
3394 } while (!ispkt);
3395 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3396 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3397 bombout(("Protocol confusion"));
3398 crStopV;
3399 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3400 c_write_str(ssh, "Server refused to allocate pty\r\n");
3401 ssh->editing = ssh->echoing = 1;
3402 }
3403 logevent("Allocated pty");
3404 } else {
3405 ssh->editing = ssh->echoing = 1;
3406 }
3407
3408 if (ssh->cfg.compression) {
3409 send_packet(ssh, SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END);
3410 do {
3411 crReturnV;
3412 } while (!ispkt);
3413 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3414 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3415 bombout(("Protocol confusion"));
3416 crStopV;
3417 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3418 c_write_str(ssh, "Server refused to compress\r\n");
3419 }
3420 logevent("Started compression");
3421 ssh->v1_compressing = TRUE;
3422 ssh->cs_comp_ctx = zlib_compress_init();
3423 logevent("Initialised zlib (RFC1950) compression");
3424 ssh->sc_comp_ctx = zlib_decompress_init();
3425 logevent("Initialised zlib (RFC1950) decompression");
3426 }
3427
3428 /*
3429 * Start the shell or command.
3430 *
3431 * Special case: if the first-choice command is an SSH2
3432 * subsystem (hence not usable here) and the second choice
3433 * exists, we fall straight back to that.
3434 */
3435 {
3436 char *cmd = ssh->cfg.remote_cmd_ptr;
3437
3438 if (ssh->cfg.ssh_subsys && ssh->cfg.remote_cmd_ptr2) {
3439 cmd = ssh->cfg.remote_cmd_ptr2;
3440 ssh->fallback_cmd = TRUE;
3441 }
3442 if (*cmd)
3443 send_packet(ssh, SSH1_CMSG_EXEC_CMD, PKT_STR, cmd, PKT_END);
3444 else
3445 send_packet(ssh, SSH1_CMSG_EXEC_SHELL, PKT_END);
3446 logevent("Started session");
3447 }
3448
3449 ssh->state = SSH_STATE_SESSION;
3450 if (ssh->size_needed)
3451 ssh_size(ssh, ssh->term_width, ssh->term_height);
3452 if (ssh->eof_needed)
3453 ssh_special(ssh, TS_EOF);
3454
3455 if (ssh->ldisc)
3456 ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */
3457 ssh->send_ok = 1;
3458 ssh->channels = newtree234(ssh_channelcmp);
3459 while (1) {
3460 crReturnV;
3461 if (ispkt) {
3462 if (ssh->pktin.type == SSH1_SMSG_STDOUT_DATA ||
3463 ssh->pktin.type == SSH1_SMSG_STDERR_DATA) {
3464 long len = GET_32BIT(ssh->pktin.body);
3465 int bufsize =
3466 from_backend(ssh->frontend,
3467 ssh->pktin.type == SSH1_SMSG_STDERR_DATA,
3468 (char *)(ssh->pktin.body) + 4, len);
3469 if (!ssh->v1_stdout_throttling && bufsize > SSH1_BUFFER_LIMIT) {
3470 ssh->v1_stdout_throttling = 1;
3471 ssh1_throttle(ssh, +1);
3472 }
3473 } else if (ssh->pktin.type == SSH1_MSG_DISCONNECT) {
3474 ssh_closing((Plug)ssh, NULL, 0, 0);
3475 logevent("Received disconnect request");
3476 crStopV;
3477 } else if (ssh->pktin.type == SSH1_SMSG_X11_OPEN) {
3478 /* Remote side is trying to open a channel to talk to our
3479 * X-Server. Give them back a local channel number. */
3480 struct ssh_channel *c;
3481
3482 logevent("Received X11 connect request");
3483 /* Refuse if X11 forwarding is disabled. */
3484 if (!ssh->X11_fwd_enabled) {
3485 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3486 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
3487 logevent("Rejected X11 connect request");
3488 } else {
3489 c = snew(struct ssh_channel);
3490 c->ssh = ssh;
3491
3492 if (x11_init(&c->u.x11.s, ssh->cfg.x11_display, c,
3493 ssh->x11auth, NULL, -1, &ssh->cfg) != NULL) {
3494 logevent("opening X11 forward connection failed");
3495 sfree(c);
3496 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3497 PKT_INT, GET_32BIT(ssh->pktin.body),
3498 PKT_END);
3499 } else {
3500 logevent
3501 ("opening X11 forward connection succeeded");
3502 c->remoteid = GET_32BIT(ssh->pktin.body);
3503 c->localid = alloc_channel_id(ssh);
3504 c->closes = 0;
3505 c->v.v1.throttling = 0;
3506 c->type = CHAN_X11; /* identify channel type */
3507 add234(ssh->channels, c);
3508 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3509 PKT_INT, c->remoteid, PKT_INT,
3510 c->localid, PKT_END);
3511 logevent("Opened X11 forward channel");
3512 }
3513 }
3514 } else if (ssh->pktin.type == SSH1_SMSG_AGENT_OPEN) {
3515 /* Remote side is trying to open a channel to talk to our
3516 * agent. Give them back a local channel number. */
3517 struct ssh_channel *c;
3518
3519 /* Refuse if agent forwarding is disabled. */
3520 if (!ssh->agentfwd_enabled) {
3521 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3522 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
3523 } else {
3524 c = snew(struct ssh_channel);
3525 c->ssh = ssh;
3526 c->remoteid = GET_32BIT(ssh->pktin.body);
3527 c->localid = alloc_channel_id(ssh);
3528 c->closes = 0;
3529 c->v.v1.throttling = 0;
3530 c->type = CHAN_AGENT; /* identify channel type */
3531 c->u.a.lensofar = 0;
3532 add234(ssh->channels, c);
3533 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3534 PKT_INT, c->remoteid, PKT_INT, c->localid,
3535 PKT_END);
3536 }
3537 } else if (ssh->pktin.type == SSH1_MSG_PORT_OPEN) {
3538 /* Remote side is trying to open a channel to talk to a
3539 * forwarded port. Give them back a local channel number. */
3540 struct ssh_channel *c;
3541 struct ssh_rportfwd pf;
3542 int hostsize, port;
3543 char host[256], buf[1024];
3544 char *p, *h;
3545 const char *e;
3546 c = snew(struct ssh_channel);
3547 c->ssh = ssh;
3548
3549 hostsize = GET_32BIT(ssh->pktin.body+4);
3550 for (h = host, p = (char *)(ssh->pktin.body+8);
3551 hostsize != 0; hostsize--) {
3552 if (h+1 < host+sizeof(host))
3553 *h++ = *p;
3554 p++;
3555 }
3556 *h = 0;
3557 port = GET_32BIT(p);
3558
3559 strcpy(pf.dhost, host);
3560 pf.dport = port;
3561
3562 if (find234(ssh->rportfwds, &pf, NULL) == NULL) {
3563 sprintf(buf, "Rejected remote port open request for %s:%d",
3564 host, port);
3565 logevent(buf);
3566 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3567 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
3568 } else {
3569 sprintf(buf, "Received remote port open request for %s:%d",
3570 host, port);
3571 logevent(buf);
3572 e = pfd_newconnect(&c->u.pfd.s, host, port, c, &ssh->cfg);
3573 if (e != NULL) {
3574 char buf[256];
3575 sprintf(buf, "Port open failed: %s", e);
3576 logevent(buf);
3577 sfree(c);
3578 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3579 PKT_INT, GET_32BIT(ssh->pktin.body),
3580 PKT_END);
3581 } else {
3582 c->remoteid = GET_32BIT(ssh->pktin.body);
3583 c->localid = alloc_channel_id(ssh);
3584 c->closes = 0;
3585 c->v.v1.throttling = 0;
3586 c->type = CHAN_SOCKDATA; /* identify channel type */
3587 add234(ssh->channels, c);
3588 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3589 PKT_INT, c->remoteid, PKT_INT,
3590 c->localid, PKT_END);
3591 logevent("Forwarded port opened successfully");
3592 }
3593 }
3594
3595 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_OPEN_CONFIRMATION) {
3596 unsigned int remoteid = GET_32BIT(ssh->pktin.body);
3597 unsigned int localid = GET_32BIT(ssh->pktin.body+4);
3598 struct ssh_channel *c;
3599
3600 c = find234(ssh->channels, &remoteid, ssh_channelfind);
3601 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
3602 c->remoteid = localid;
3603 c->type = CHAN_SOCKDATA;
3604 c->v.v1.throttling = 0;
3605 pfd_confirm(c->u.pfd.s);
3606 }
3607
3608 if (c && c->closes) {
3609 /*
3610 * We have a pending close on this channel,
3611 * which we decided on before the server acked
3612 * the channel open. So now we know the
3613 * remoteid, we can close it again.
3614 */
3615 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE,
3616 PKT_INT, c->remoteid, PKT_END);
3617 }
3618
3619 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_OPEN_FAILURE) {
3620 unsigned int remoteid = GET_32BIT(ssh->pktin.body);
3621 struct ssh_channel *c;
3622
3623 c = find234(ssh->channels, &remoteid, ssh_channelfind);
3624 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
3625 logevent("Forwarded connection refused by server");
3626 pfd_close(c->u.pfd.s);
3627 del234(ssh->channels, c);
3628 sfree(c);
3629 }
3630
3631 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ||
3632 ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION) {
3633 /* Remote side closes a channel. */
3634 unsigned i = GET_32BIT(ssh->pktin.body);
3635 struct ssh_channel *c;
3636 c = find234(ssh->channels, &i, ssh_channelfind);
3637 if (c && ((int)c->remoteid) != -1) {
3638 int closetype;
3639 closetype =
3640 (ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ? 1 : 2);
3641
3642 if ((c->closes == 0) && (c->type == CHAN_X11)) {
3643 logevent("Forwarded X11 connection terminated");
3644 assert(c->u.x11.s != NULL);
3645 x11_close(c->u.x11.s);
3646 c->u.x11.s = NULL;
3647 }
3648 if ((c->closes == 0) && (c->type == CHAN_SOCKDATA)) {
3649 logevent("Forwarded port closed");
3650 assert(c->u.pfd.s != NULL);
3651 pfd_close(c->u.pfd.s);
3652 c->u.pfd.s = NULL;
3653 }
3654
3655 c->closes |= (closetype << 2); /* seen this message */
3656 if (!(c->closes & closetype)) {
3657 send_packet(ssh, ssh->pktin.type, PKT_INT, c->remoteid,
3658 PKT_END);
3659 c->closes |= closetype; /* sent it too */
3660 }
3661
3662 if (c->closes == 15) {
3663 del234(ssh->channels, c);
3664 sfree(c);
3665 }
3666 } else {
3667 bombout(("Received CHANNEL_CLOSE%s for %s channel %d\n",
3668 ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ? "" :
3669 "_CONFIRMATION", c ? "half-open" : "nonexistent",
3670 i));
3671 crStopV;
3672 }
3673 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_DATA) {
3674 /* Data sent down one of our channels. */
3675 int i = GET_32BIT(ssh->pktin.body);
3676 int len = GET_32BIT(ssh->pktin.body + 4);
3677 unsigned char *p = ssh->pktin.body + 8;
3678 struct ssh_channel *c;
3679 c = find234(ssh->channels, &i, ssh_channelfind);
3680 if (c) {
3681 int bufsize = 0;
3682 switch (c->type) {
3683 case CHAN_X11:
3684 bufsize = x11_send(c->u.x11.s, (char *)p, len);
3685 break;
3686 case CHAN_SOCKDATA:
3687 bufsize = pfd_send(c->u.pfd.s, (char *)p, len);
3688 break;
3689 case CHAN_AGENT:
3690 /* Data for an agent message. Buffer it. */
3691 while (len > 0) {
3692 if (c->u.a.lensofar < 4) {
3693 int l = min(4 - c->u.a.lensofar, len);
3694 memcpy(c->u.a.msglen + c->u.a.lensofar, p,
3695 l);
3696 p += l;
3697 len -= l;
3698 c->u.a.lensofar += l;
3699 }
3700 if (c->u.a.lensofar == 4) {
3701 c->u.a.totallen =
3702 4 + GET_32BIT(c->u.a.msglen);
3703 c->u.a.message = snewn(c->u.a.totallen,
3704 unsigned char);
3705 memcpy(c->u.a.message, c->u.a.msglen, 4);
3706 }
3707 if (c->u.a.lensofar >= 4 && len > 0) {
3708 int l =
3709 min(c->u.a.totallen - c->u.a.lensofar,
3710 len);
3711 memcpy(c->u.a.message + 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 == c->u.a.totallen) {
3718 void *reply;
3719 int replylen;
3720 if (agent_query(c->u.a.message,
3721 c->u.a.totallen,
3722 &reply, &replylen,
3723 ssh_agentf_callback, c))
3724 ssh_agentf_callback(c, reply, replylen);
3725 sfree(c->u.a.message);
3726 c->u.a.lensofar = 0;
3727 }
3728 }
3729 bufsize = 0; /* agent channels never back up */
3730 break;
3731 }
3732 if (!c->v.v1.throttling && bufsize > SSH1_BUFFER_LIMIT) {
3733 c->v.v1.throttling = 1;
3734 ssh1_throttle(ssh, +1);
3735 }
3736 }
3737 } else if (ssh->pktin.type == SSH1_SMSG_SUCCESS) {
3738 /* may be from EXEC_SHELL on some servers */
3739 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3740 /* may be from EXEC_SHELL on some servers
3741 * if no pty is available or in other odd cases. Ignore */
3742 } else if (ssh->pktin.type == SSH1_SMSG_EXIT_STATUS) {
3743 char buf[100];
3744 ssh->exitcode = GET_32BIT(ssh->pktin.body);
3745 sprintf(buf, "Server sent command exit status %d",
3746 ssh->exitcode);
3747 logevent(buf);
3748 send_packet(ssh, SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
3749 /*
3750 * In case `helpful' firewalls or proxies tack
3751 * extra human-readable text on the end of the
3752 * session which we might mistake for another
3753 * encrypted packet, we close the session once
3754 * we've sent EXIT_CONFIRMATION.
3755 */
3756 ssh_closing((Plug)ssh, NULL, 0, 0);
3757 crStopV;
3758 } else {
3759 bombout(("Strange packet received: type %d", ssh->pktin.type));
3760 crStopV;
3761 }
3762 } else {
3763 while (inlen > 0) {
3764 int len = min(inlen, 512);
3765 send_packet(ssh, SSH1_CMSG_STDIN_DATA,
3766 PKT_INT, len, PKT_DATA, in, len, PKT_END);
3767 in += len;
3768 inlen -= len;
3769 }
3770 }
3771 }
3772
3773 crFinishV;
3774 }
3775
3776 /*
3777 * Utility routine for decoding comma-separated strings in KEXINIT.
3778 */
3779 static int in_commasep_string(char *needle, char *haystack, int haylen)
3780 {
3781 int needlen;
3782 if (!needle || !haystack) /* protect against null pointers */
3783 return 0;
3784 needlen = strlen(needle);
3785 while (1) {
3786 /*
3787 * Is it at the start of the string?
3788 */
3789 if (haylen >= needlen && /* haystack is long enough */
3790 !memcmp(needle, haystack, needlen) && /* initial match */
3791 (haylen == needlen || haystack[needlen] == ',')
3792 /* either , or EOS follows */
3793 )
3794 return 1;
3795 /*
3796 * If not, search for the next comma and resume after that.
3797 * If no comma found, terminate.
3798 */
3799 while (haylen > 0 && *haystack != ',')
3800 haylen--, haystack++;
3801 if (haylen == 0)
3802 return 0;
3803 haylen--, haystack++; /* skip over comma itself */
3804 }
3805 }
3806
3807 /*
3808 * SSH2 key creation method.
3809 */
3810 static void ssh2_mkkey(Ssh ssh, Bignum K, unsigned char *H,
3811 unsigned char *sessid, char chr,
3812 unsigned char *keyspace)
3813 {
3814 SHA_State s;
3815 /* First 20 bytes. */
3816 SHA_Init(&s);
3817 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
3818 sha_mpint(&s, K);
3819 SHA_Bytes(&s, H, 20);
3820 SHA_Bytes(&s, &chr, 1);
3821 SHA_Bytes(&s, sessid, 20);
3822 SHA_Final(&s, keyspace);
3823 /* Next 20 bytes. */
3824 SHA_Init(&s);
3825 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
3826 sha_mpint(&s, K);
3827 SHA_Bytes(&s, H, 20);
3828 SHA_Bytes(&s, keyspace, 20);
3829 SHA_Final(&s, keyspace + 20);
3830 }
3831
3832 /*
3833 * Handle the SSH2 transport layer.
3834 */
3835 static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
3836 {
3837 struct do_ssh2_transport_state {
3838 int nbits, pbits, warn;
3839 Bignum p, g, e, f, K;
3840 int kex_init_value, kex_reply_value;
3841 const struct ssh_mac **maclist;
3842 int nmacs;
3843 const struct ssh2_cipher *cscipher_tobe;
3844 const struct ssh2_cipher *sccipher_tobe;
3845 const struct ssh_mac *csmac_tobe;
3846 const struct ssh_mac *scmac_tobe;
3847 const struct ssh_compress *cscomp_tobe;
3848 const struct ssh_compress *sccomp_tobe;
3849 char *hostkeydata, *sigdata, *keystr, *fingerprint;
3850 int hostkeylen, siglen;
3851 void *hkey; /* actual host key */
3852 unsigned char exchange_hash[20];
3853 int n_preferred_ciphers;
3854 const struct ssh2_ciphers *preferred_ciphers[CIPHER_MAX];
3855 const struct ssh_compress *preferred_comp;
3856 int first_kex;
3857 };
3858 crState(do_ssh2_transport_state);
3859
3860 crBegin(ssh->do_ssh2_transport_crstate);
3861
3862 s->cscipher_tobe = s->sccipher_tobe = NULL;
3863 s->csmac_tobe = s->scmac_tobe = NULL;
3864 s->cscomp_tobe = s->sccomp_tobe = NULL;
3865
3866 random_init();
3867 s->first_kex = 1;
3868
3869 {
3870 int i;
3871 /*
3872 * Set up the preferred ciphers. (NULL => warn below here)
3873 */
3874 s->n_preferred_ciphers = 0;
3875 for (i = 0; i < CIPHER_MAX; i++) {
3876 switch (ssh->cfg.ssh_cipherlist[i]) {
3877 case CIPHER_BLOWFISH:
3878 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_blowfish;
3879 break;
3880 case CIPHER_DES:
3881 if (ssh->cfg.ssh2_des_cbc) {
3882 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_des;
3883 }
3884 break;
3885 case CIPHER_3DES:
3886 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_3des;
3887 break;
3888 case CIPHER_AES:
3889 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_aes;
3890 break;
3891 case CIPHER_WARN:
3892 /* Flag for later. Don't bother if it's the last in
3893 * the list. */
3894 if (i < CIPHER_MAX - 1) {
3895 s->preferred_ciphers[s->n_preferred_ciphers++] = NULL;
3896 }
3897 break;
3898 }
3899 }
3900 }
3901
3902 /*
3903 * Set up preferred compression.
3904 */
3905 if (ssh->cfg.compression)
3906 s->preferred_comp = &ssh_zlib;
3907 else
3908 s->preferred_comp = &ssh_comp_none;
3909
3910 /*
3911 * Be prepared to work around the buggy MAC problem.
3912 */
3913 if (ssh->remote_bugs & BUG_SSH2_HMAC)
3914 s->maclist = buggymacs, s->nmacs = lenof(buggymacs);
3915 else
3916 s->maclist = macs, s->nmacs = lenof(macs);
3917
3918 begin_key_exchange:
3919 {
3920 int i, j, cipherstr_started;
3921
3922 /*
3923 * Construct and send our key exchange packet.
3924 */
3925 ssh2_pkt_init(ssh, SSH2_MSG_KEXINIT);
3926 for (i = 0; i < 16; i++)
3927 ssh2_pkt_addbyte(ssh, (unsigned char) random_byte());
3928 /* List key exchange algorithms. */
3929 ssh2_pkt_addstring_start(ssh);
3930 for (i = 0; i < lenof(kex_algs); i++) {
3931 if (kex_algs[i] == &ssh_diffiehellman_gex &&
3932 (ssh->remote_bugs & BUG_SSH2_DH_GEX))
3933 continue;
3934 ssh2_pkt_addstring_str(ssh, kex_algs[i]->name);
3935 if (i < lenof(kex_algs) - 1)
3936 ssh2_pkt_addstring_str(ssh, ",");
3937 }
3938 /* List server host key algorithms. */
3939 ssh2_pkt_addstring_start(ssh);
3940 for (i = 0; i < lenof(hostkey_algs); i++) {
3941 ssh2_pkt_addstring_str(ssh, hostkey_algs[i]->name);
3942 if (i < lenof(hostkey_algs) - 1)
3943 ssh2_pkt_addstring_str(ssh, ",");
3944 }
3945 /* List client->server encryption algorithms. */
3946 ssh2_pkt_addstring_start(ssh);
3947 cipherstr_started = 0;
3948 for (i = 0; i < s->n_preferred_ciphers; i++) {
3949 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3950 if (!c) continue; /* warning flag */
3951 for (j = 0; j < c->nciphers; j++) {
3952 if (cipherstr_started)
3953 ssh2_pkt_addstring_str(ssh, ",");
3954 ssh2_pkt_addstring_str(ssh, c->list[j]->name);
3955 cipherstr_started = 1;
3956 }
3957 }
3958 /* List server->client encryption algorithms. */
3959 ssh2_pkt_addstring_start(ssh);
3960 cipherstr_started = 0;
3961 for (i = 0; i < s->n_preferred_ciphers; i++) {
3962 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3963 if (!c) continue; /* warning flag */
3964 for (j = 0; j < c->nciphers; j++) {
3965 if (cipherstr_started)
3966 ssh2_pkt_addstring_str(ssh, ",");
3967 ssh2_pkt_addstring_str(ssh, c->list[j]->name);
3968 cipherstr_started = 1;
3969 }
3970 }
3971 /* List client->server MAC algorithms. */
3972 ssh2_pkt_addstring_start(ssh);
3973 for (i = 0; i < s->nmacs; i++) {
3974 ssh2_pkt_addstring_str(ssh, s->maclist[i]->name);
3975 if (i < s->nmacs - 1)
3976 ssh2_pkt_addstring_str(ssh, ",");
3977 }
3978 /* List server->client MAC algorithms. */
3979 ssh2_pkt_addstring_start(ssh);
3980 for (i = 0; i < s->nmacs; i++) {
3981 ssh2_pkt_addstring_str(ssh, s->maclist[i]->name);
3982 if (i < s->nmacs - 1)
3983 ssh2_pkt_addstring_str(ssh, ",");
3984 }
3985 /* List client->server compression algorithms. */
3986 ssh2_pkt_addstring_start(ssh);
3987 for (i = 0; i < lenof(compressions) + 1; i++) {
3988 const struct ssh_compress *c =
3989 i == 0 ? s->preferred_comp : compressions[i - 1];
3990 ssh2_pkt_addstring_str(ssh, c->name);
3991 if (i < lenof(compressions))
3992 ssh2_pkt_addstring_str(ssh, ",");
3993 }
3994 /* List server->client compression algorithms. */
3995 ssh2_pkt_addstring_start(ssh);
3996 for (i = 0; i < lenof(compressions) + 1; i++) {
3997 const struct ssh_compress *c =
3998 i == 0 ? s->preferred_comp : compressions[i - 1];
3999 ssh2_pkt_addstring_str(ssh, c->name);
4000 if (i < lenof(compressions))
4001 ssh2_pkt_addstring_str(ssh, ",");
4002 }
4003 /* List client->server languages. Empty list. */
4004 ssh2_pkt_addstring_start(ssh);
4005 /* List server->client languages. Empty list. */
4006 ssh2_pkt_addstring_start(ssh);
4007 /* First KEX packet does _not_ follow, because we're not that brave. */
4008 ssh2_pkt_addbool(ssh, FALSE);
4009 /* Reserved. */
4010 ssh2_pkt_adduint32(ssh, 0);
4011 }
4012
4013 ssh->exhash = ssh->exhashbase;
4014 sha_string(&ssh->exhash, ssh->pktout.data + 5, ssh->pktout.length - 5);
4015
4016 ssh2_pkt_send(ssh);
4017
4018 if (!ispkt)
4019 crWaitUntil(ispkt);
4020 if (ssh->pktin.length > 5)
4021 sha_string(&ssh->exhash, ssh->pktin.data + 5, ssh->pktin.length - 5);
4022
4023 /*
4024 * Now examine the other side's KEXINIT to see what we're up
4025 * to.
4026 */
4027 {
4028 char *str;
4029 int i, j, len;
4030
4031 if (ssh->pktin.type != SSH2_MSG_KEXINIT) {
4032 bombout(("expected key exchange packet from server"));
4033 crStop(0);
4034 }
4035 ssh->kex = NULL;
4036 ssh->hostkey = NULL;
4037 s->cscipher_tobe = NULL;
4038 s->sccipher_tobe = NULL;
4039 s->csmac_tobe = NULL;
4040 s->scmac_tobe = NULL;
4041 s->cscomp_tobe = NULL;
4042 s->sccomp_tobe = NULL;
4043 ssh->pktin.savedpos += 16; /* skip garbage cookie */
4044 ssh2_pkt_getstring(ssh, &str, &len); /* key exchange algorithms */
4045 for (i = 0; i < lenof(kex_algs); i++) {
4046 if (kex_algs[i] == &ssh_diffiehellman_gex &&
4047 (ssh->remote_bugs & BUG_SSH2_DH_GEX))
4048 continue;
4049 if (in_commasep_string(kex_algs[i]->name, str, len)) {
4050 ssh->kex = kex_algs[i];
4051 break;
4052 }
4053 }
4054 ssh2_pkt_getstring(ssh, &str, &len); /* host key algorithms */
4055 for (i = 0; i < lenof(hostkey_algs); i++) {
4056 if (in_commasep_string(hostkey_algs[i]->name, str, len)) {
4057 ssh->hostkey = hostkey_algs[i];
4058 break;
4059 }
4060 }
4061 ssh2_pkt_getstring(ssh, &str, &len); /* client->server cipher */
4062 s->warn = 0;
4063 for (i = 0; i < s->n_preferred_ciphers; i++) {
4064 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
4065 if (!c) {
4066 s->warn = 1;
4067 } else {
4068 for (j = 0; j < c->nciphers; j++) {
4069 if (in_commasep_string(c->list[j]->name, str, len)) {
4070 s->cscipher_tobe = c->list[j];
4071 break;
4072 }
4073 }
4074 }
4075 if (s->cscipher_tobe) {
4076 if (s->warn)
4077 askcipher(ssh->frontend, s->cscipher_tobe->name, 1);
4078 break;
4079 }
4080 }
4081 if (!s->cscipher_tobe) {
4082 bombout(("Couldn't agree a client-to-server cipher (available: %s)",
4083 str ? str : "(null)"));
4084 crStop(0);
4085 }
4086
4087 ssh2_pkt_getstring(ssh, &str, &len); /* server->client cipher */
4088 s->warn = 0;
4089 for (i = 0; i < s->n_preferred_ciphers; i++) {
4090 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
4091 if (!c) {
4092 s->warn = 1;
4093 } else {
4094 for (j = 0; j < c->nciphers; j++) {
4095 if (in_commasep_string(c->list[j]->name, str, len)) {
4096 s->sccipher_tobe = c->list[j];
4097 break;
4098 }
4099 }
4100 }
4101 if (s->sccipher_tobe) {
4102 if (s->warn)
4103 askcipher(ssh->frontend, s->sccipher_tobe->name, 2);
4104 break;
4105 }
4106 }
4107 if (!s->sccipher_tobe) {
4108 bombout(("Couldn't agree a server-to-client cipher (available: %s)",
4109 str ? str : "(null)"));
4110 crStop(0);
4111 }
4112
4113 ssh2_pkt_getstring(ssh, &str, &len); /* client->server mac */
4114 for (i = 0; i < s->nmacs; i++) {
4115 if (in_commasep_string(s->maclist[i]->name, str, len)) {
4116 s->csmac_tobe = s->maclist[i];
4117 break;
4118 }
4119 }
4120 ssh2_pkt_getstring(ssh, &str, &len); /* server->client mac */
4121 for (i = 0; i < s->nmacs; i++) {
4122 if (in_commasep_string(s->maclist[i]->name, str, len)) {
4123 s->scmac_tobe = s->maclist[i];
4124 break;
4125 }
4126 }
4127 ssh2_pkt_getstring(ssh, &str, &len); /* client->server compression */
4128 for (i = 0; i < lenof(compressions) + 1; i++) {
4129 const struct ssh_compress *c =
4130 i == 0 ? s->preferred_comp : compressions[i - 1];
4131 if (in_commasep_string(c->name, str, len)) {
4132 s->cscomp_tobe = c;
4133 break;
4134 }
4135 }
4136 ssh2_pkt_getstring(ssh, &str, &len); /* server->client compression */
4137 for (i = 0; i < lenof(compressions) + 1; i++) {
4138 const struct ssh_compress *c =
4139 i == 0 ? s->preferred_comp : compressions[i - 1];
4140 if (in_commasep_string(c->name, str, len)) {
4141 s->sccomp_tobe = c;
4142 break;
4143 }
4144 }
4145 }
4146
4147 /*
4148 * Work out the number of bits of key we will need from the key
4149 * exchange. We start with the maximum key length of either
4150 * cipher...
4151 */
4152 {
4153 int csbits, scbits;
4154
4155 csbits = s->cscipher_tobe->keylen;
4156 scbits = s->sccipher_tobe->keylen;
4157 s->nbits = (csbits > scbits ? csbits : scbits);
4158 }
4159 /* The keys only have 160-bit entropy, since they're based on
4160 * a SHA-1 hash. So cap the key size at 160 bits. */
4161 if (s->nbits > 160)
4162 s->nbits = 160;
4163
4164 /*
4165 * If we're doing Diffie-Hellman group exchange, start by
4166 * requesting a group.
4167 */
4168 if (ssh->kex == &ssh_diffiehellman_gex) {
4169 logevent("Doing Diffie-Hellman group exchange");
4170 ssh->pkt_ctx |= SSH2_PKTCTX_DHGEX;
4171 /*
4172 * Work out how big a DH group we will need to allow that
4173 * much data.
4174 */
4175 s->pbits = 512 << ((s->nbits - 1) / 64);
4176 ssh2_pkt_init(ssh, SSH2_MSG_KEX_DH_GEX_REQUEST);
4177 ssh2_pkt_adduint32(ssh, s->pbits);
4178 ssh2_pkt_send(ssh);
4179
4180 crWaitUntil(ispkt);
4181 if (ssh->pktin.type != SSH2_MSG_KEX_DH_GEX_GROUP) {
4182 bombout(("expected key exchange group packet from server"));
4183 crStop(0);
4184 }
4185 s->p = ssh2_pkt_getmp(ssh);
4186 s->g = ssh2_pkt_getmp(ssh);
4187 ssh->kex_ctx = dh_setup_group(s->p, s->g);
4188 s->kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT;
4189 s->kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY;
4190 } else {
4191 ssh->pkt_ctx |= SSH2_PKTCTX_DHGROUP1;
4192 ssh->kex_ctx = dh_setup_group1();
4193 s->kex_init_value = SSH2_MSG_KEXDH_INIT;
4194 s->kex_reply_value = SSH2_MSG_KEXDH_REPLY;
4195 }
4196
4197 logevent("Doing Diffie-Hellman key exchange");
4198 /*
4199 * Now generate and send e for Diffie-Hellman.
4200 */
4201 s->e = dh_create_e(ssh->kex_ctx, s->nbits * 2);
4202 ssh2_pkt_init(ssh, s->kex_init_value);
4203 ssh2_pkt_addmp(ssh, s->e);
4204 ssh2_pkt_send(ssh);
4205
4206 crWaitUntil(ispkt);
4207 if (ssh->pktin.type != s->kex_reply_value) {
4208 bombout(("expected key exchange reply packet from server"));
4209 crStop(0);
4210 }
4211 ssh2_pkt_getstring(ssh, &s->hostkeydata, &s->hostkeylen);
4212 s->f = ssh2_pkt_getmp(ssh);
4213 ssh2_pkt_getstring(ssh, &s->sigdata, &s->siglen);
4214
4215 s->K = dh_find_K(ssh->kex_ctx, s->f);
4216
4217 sha_string(&ssh->exhash, s->hostkeydata, s->hostkeylen);
4218 if (ssh->kex == &ssh_diffiehellman_gex) {
4219 sha_uint32(&ssh->exhash, s->pbits);
4220 sha_mpint(&ssh->exhash, s->p);
4221 sha_mpint(&ssh->exhash, s->g);
4222 }
4223 sha_mpint(&ssh->exhash, s->e);
4224 sha_mpint(&ssh->exhash, s->f);
4225 sha_mpint(&ssh->exhash, s->K);
4226 SHA_Final(&ssh->exhash, s->exchange_hash);
4227
4228 dh_cleanup(ssh->kex_ctx);
4229 ssh->kex_ctx = NULL;
4230
4231 #if 0
4232 debug(("Exchange hash is:\n"));
4233 dmemdump(s->exchange_hash, 20);
4234 #endif
4235
4236 s->hkey = ssh->hostkey->newkey(s->hostkeydata, s->hostkeylen);
4237 if (!s->hkey ||
4238 !ssh->hostkey->verifysig(s->hkey, s->sigdata, s->siglen,
4239 (char *)s->exchange_hash, 20)) {
4240 bombout(("Server's host key did not match the signature supplied"));
4241 crStop(0);
4242 }
4243
4244 /*
4245 * Authenticate remote host: verify host key. (We've already
4246 * checked the signature of the exchange hash.)
4247 */
4248 s->keystr = ssh->hostkey->fmtkey(s->hkey);
4249 s->fingerprint = ssh->hostkey->fingerprint(s->hkey);
4250 verify_ssh_host_key(ssh->frontend,
4251 ssh->savedhost, ssh->savedport, ssh->hostkey->keytype,
4252 s->keystr, s->fingerprint);
4253 if (s->first_kex) { /* don't bother logging this in rekeys */
4254 logevent("Host key fingerprint is:");
4255 logevent(s->fingerprint);
4256 }
4257 sfree(s->fingerprint);
4258 sfree(s->keystr);
4259 ssh->hostkey->freekey(s->hkey);
4260
4261 /*
4262 * Send SSH2_MSG_NEWKEYS.
4263 */
4264 ssh2_pkt_init(ssh, SSH2_MSG_NEWKEYS);
4265 ssh2_pkt_send(ssh);
4266
4267 /*
4268 * Expect SSH2_MSG_NEWKEYS from server.
4269 */
4270 crWaitUntil(ispkt);
4271 if (ssh->pktin.type != SSH2_MSG_NEWKEYS) {
4272 bombout(("expected new-keys packet from server"));
4273 crStop(0);
4274 }
4275
4276 /*
4277 * Create and initialise session keys.
4278 */
4279 if (ssh->cs_cipher_ctx)
4280 ssh->cscipher->free_context(ssh->cs_cipher_ctx);
4281 ssh->cscipher = s->cscipher_tobe;
4282 ssh->cs_cipher_ctx = ssh->cscipher->make_context();
4283
4284 if (ssh->sc_cipher_ctx)
4285 ssh->sccipher->free_context(ssh->sc_cipher_ctx);
4286 ssh->sccipher = s->sccipher_tobe;
4287 ssh->sc_cipher_ctx = ssh->sccipher->make_context();
4288
4289 if (ssh->cs_mac_ctx)
4290 ssh->csmac->free_context(ssh->cs_mac_ctx);
4291 ssh->csmac = s->csmac_tobe;
4292 ssh->cs_mac_ctx = ssh->csmac->make_context();
4293
4294 if (ssh->sc_mac_ctx)
4295 ssh->scmac->free_context(ssh->sc_mac_ctx);
4296 ssh->scmac = s->scmac_tobe;
4297 ssh->sc_mac_ctx = ssh->scmac->make_context();
4298
4299 if (ssh->cs_comp_ctx)
4300 ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
4301 ssh->cscomp = s->cscomp_tobe;
4302 ssh->cs_comp_ctx = ssh->cscomp->compress_init();
4303
4304 if (ssh->sc_comp_ctx)
4305 ssh->sccomp->decompress_cleanup(ssh->sc_comp_ctx);
4306 ssh->sccomp = s->sccomp_tobe;
4307 ssh->sc_comp_ctx = ssh->sccomp->decompress_init();
4308
4309 /*
4310 * Set IVs after keys. Here we use the exchange hash from the
4311 * _first_ key exchange.
4312 */
4313 {
4314 unsigned char keyspace[40];
4315 if (s->first_kex)
4316 memcpy(ssh->v2_session_id, s->exchange_hash,
4317 sizeof(s->exchange_hash));
4318 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'C',keyspace);
4319 ssh->cscipher->setkey(ssh->cs_cipher_ctx, keyspace);
4320 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'D',keyspace);
4321 ssh->sccipher->setkey(ssh->sc_cipher_ctx, keyspace);
4322 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'A',keyspace);
4323 ssh->cscipher->setiv(ssh->cs_cipher_ctx, keyspace);
4324 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'B',keyspace);
4325 ssh->sccipher->setiv(ssh->sc_cipher_ctx, keyspace);
4326 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'E',keyspace);
4327 ssh->csmac->setkey(ssh->cs_mac_ctx, keyspace);
4328 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'F',keyspace);
4329 ssh->scmac->setkey(ssh->sc_mac_ctx, keyspace);
4330 }
4331 logeventf(ssh, "Initialised %.200s client->server encryption",
4332 ssh->cscipher->text_name);
4333 logeventf(ssh, "Initialised %.200s server->client encryption",
4334 ssh->sccipher->text_name);
4335 if (ssh->cscomp->text_name)
4336 logeventf(ssh, "Initialised %s compression",
4337 ssh->cscomp->text_name);
4338 if (ssh->sccomp->text_name)
4339 logeventf(ssh, "Initialised %s decompression",
4340 ssh->sccomp->text_name);
4341
4342 /*
4343 * If this is the first key exchange phase, we must pass the
4344 * SSH2_MSG_NEWKEYS packet to the next layer, not because it
4345 * wants to see it but because it will need time to initialise
4346 * itself before it sees an actual packet. In subsequent key
4347 * exchange phases, we don't pass SSH2_MSG_NEWKEYS on, because
4348 * it would only confuse the layer above.
4349 */
4350 if (!s->first_kex) {
4351 crReturn(0);
4352 }
4353 s->first_kex = 0;
4354
4355 /*
4356 * Now we're encrypting. Begin returning 1 to the protocol main
4357 * function so that other things can run on top of the
4358 * transport. If we ever see a KEXINIT, we must go back to the
4359 * start.
4360 */
4361 while (!(ispkt && ssh->pktin.type == SSH2_MSG_KEXINIT)) {
4362 crReturn(1);
4363 }
4364 logevent("Server initiated key re-exchange");
4365 goto begin_key_exchange;
4366
4367 crFinish(1);
4368 }
4369
4370 /*
4371 * Add data to an SSH2 channel output buffer.
4372 */
4373 static void ssh2_add_channel_data(struct ssh_channel *c, char *buf,
4374 int len)
4375 {
4376 bufchain_add(&c->v.v2.outbuffer, buf, len);
4377 }
4378
4379 /*
4380 * Attempt to send data on an SSH2 channel.
4381 */
4382 static int ssh2_try_send(struct ssh_channel *c)
4383 {
4384 Ssh ssh = c->ssh;
4385
4386 while (c->v.v2.remwindow > 0 && bufchain_size(&c->v.v2.outbuffer) > 0) {
4387 int len;
4388 void *data;
4389 bufchain_prefix(&c->v.v2.outbuffer, &data, &len);
4390 if ((unsigned)len > c->v.v2.remwindow)
4391 len = c->v.v2.remwindow;
4392 if ((unsigned)len > c->v.v2.remmaxpkt)
4393 len = c->v.v2.remmaxpkt;
4394 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_DATA);
4395 ssh2_pkt_adduint32(ssh, c->remoteid);
4396 ssh2_pkt_addstring_start(ssh);
4397 ssh2_pkt_addstring_data(ssh, data, len);
4398 ssh2_pkt_send(ssh);
4399 bufchain_consume(&c->v.v2.outbuffer, len);
4400 c->v.v2.remwindow -= len;
4401 }
4402
4403 /*
4404 * After having sent as much data as we can, return the amount
4405 * still buffered.
4406 */
4407 return bufchain_size(&c->v.v2.outbuffer);
4408 }
4409
4410 /*
4411 * Potentially enlarge the window on an SSH2 channel.
4412 */
4413 static void ssh2_set_window(struct ssh_channel *c, unsigned newwin)
4414 {
4415 Ssh ssh = c->ssh;
4416
4417 /*
4418 * Never send WINDOW_ADJUST for a channel that the remote side
4419 * already thinks it's closed; there's no point, since it won't
4420 * be sending any more data anyway.
4421 */
4422 if (c->closes != 0)
4423 return;
4424
4425 if (newwin > c->v.v2.locwindow) {
4426 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST);
4427 ssh2_pkt_adduint32(ssh, c->remoteid);
4428 ssh2_pkt_adduint32(ssh, newwin - c->v.v2.locwindow);
4429 ssh2_pkt_send(ssh);
4430 c->v.v2.locwindow = newwin;
4431 }
4432 }
4433
4434 /*
4435 * Handle the SSH2 userauth and connection layers.
4436 */
4437 static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
4438 {
4439 struct do_ssh2_authconn_state {
4440 enum {
4441 AUTH_INVALID, AUTH_PUBLICKEY_AGENT, AUTH_PUBLICKEY_FILE,
4442 AUTH_PASSWORD,
4443 AUTH_KEYBOARD_INTERACTIVE
4444 } method;
4445 enum {
4446 AUTH_TYPE_NONE,
4447 AUTH_TYPE_PUBLICKEY,
4448 AUTH_TYPE_PUBLICKEY_OFFER_LOUD,
4449 AUTH_TYPE_PUBLICKEY_OFFER_QUIET,
4450 AUTH_TYPE_PASSWORD,
4451 AUTH_TYPE_KEYBOARD_INTERACTIVE,
4452 AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET
4453 } type;
4454 int gotit, need_pw, can_pubkey, can_passwd, can_keyb_inter;
4455 int tried_pubkey_config, tried_agent, tried_keyb_inter;
4456 int kbd_inter_running;
4457 int we_are_in;
4458 int num_prompts, curr_prompt, echo;
4459 char username[100];
4460 int got_username;
4461 char pwprompt[200];
4462 char password[100];
4463 void *publickey_blob;
4464 int publickey_bloblen;
4465 unsigned char request[5], *response, *p;
4466 int responselen;
4467 int keyi, nkeys;
4468 int authed;
4469 char *pkblob, *alg, *commentp;
4470 int pklen, alglen, commentlen;
4471 int siglen, retlen, len;
4472 char *q, *agentreq, *ret;
4473 int try_send;
4474 };
4475 crState(do_ssh2_authconn_state);
4476
4477 crBegin(ssh->do_ssh2_authconn_crstate);
4478
4479 /*
4480 * Request userauth protocol, and await a response to it.
4481 */
4482 ssh2_pkt_init(ssh, SSH2_MSG_SERVICE_REQUEST);
4483 ssh2_pkt_addstring(ssh, "ssh-userauth");
4484 ssh2_pkt_send(ssh);
4485 crWaitUntilV(ispkt);
4486 if (ssh->pktin.type != SSH2_MSG_SERVICE_ACCEPT) {
4487 bombout(("Server refused user authentication protocol"));
4488 crStopV;
4489 }
4490
4491 /*
4492 * We repeat this whole loop, including the username prompt,
4493 * until we manage a successful authentication. If the user
4494 * types the wrong _password_, they can be sent back to the
4495 * beginning to try another username, if this is configured on.
4496 * (If they specify a username in the config, they are never
4497 * asked, even if they do give a wrong password.)
4498 *
4499 * I think this best serves the needs of
4500 *
4501 * - the people who have no configuration, no keys, and just
4502 * want to try repeated (username,password) pairs until they
4503 * type both correctly
4504 *
4505 * - people who have keys and configuration but occasionally
4506 * need to fall back to passwords
4507 *
4508 * - people with a key held in Pageant, who might not have
4509 * logged in to a particular machine before; so they want to
4510 * type a username, and then _either_ their key will be
4511 * accepted, _or_ they will type a password. If they mistype
4512 * the username they will want to be able to get back and
4513 * retype it!
4514 */
4515 s->username[0] = '\0';
4516 s->got_username = FALSE;
4517 do {
4518 /*
4519 * Get a username.
4520 */
4521 if (s->got_username && !ssh->cfg.change_username) {
4522 /*
4523 * We got a username last time round this loop, and
4524 * with change_username turned off we don't try to get
4525 * it again.
4526 */
4527 } else if ((flags & FLAG_INTERACTIVE) && !*ssh->cfg.username) {
4528 if (ssh_get_line && !ssh_getline_pw_only) {
4529 if (!ssh_get_line("login as: ",
4530 s->username, sizeof(s->username), FALSE)) {
4531 /*
4532 * get_line failed to get a username.
4533 * Terminate.
4534 */
4535 logevent("No username provided. Abandoning session.");
4536 ssh_closing((Plug)ssh, NULL, 0, 0);
4537 crStopV;
4538 }
4539 } else {
4540 int ret; /* need not be saved across crReturn */
4541 c_write_str(ssh, "login as: ");
4542 ssh->send_ok = 1;
4543 setup_userpass_input(ssh, s->username, sizeof(s->username), 1);
4544 do {
4545 crWaitUntilV(!ispkt);
4546 ret = process_userpass_input(ssh, in, inlen);
4547 } while (ret == 0);
4548 if (ret < 0)
4549 cleanup_exit(0);
4550 c_write_str(ssh, "\r\n");
4551 }
4552 s->username[strcspn(s->username, "\n\r")] = '\0';
4553 } else {
4554 char *stuff;
4555 strncpy(s->username, ssh->cfg.username, sizeof(s->username));
4556 s->username[sizeof(s->username)-1] = '\0';
4557 if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
4558 stuff = dupprintf("Using username \"%s\".\r\n", s->username);
4559 c_write_str(ssh, stuff);
4560 sfree(stuff);
4561 }
4562 }
4563 s->got_username = TRUE;
4564
4565 /*
4566 * Send an authentication request using method "none": (a)
4567 * just in case it succeeds, and (b) so that we know what
4568 * authentication methods we can usefully try next.
4569 */
4570 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4571
4572 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4573 ssh2_pkt_addstring(ssh, s->username);
4574 ssh2_pkt_addstring(ssh, "ssh-connection");/* service requested */
4575 ssh2_pkt_addstring(ssh, "none"); /* method */
4576 ssh2_pkt_send(ssh);
4577 s->type = AUTH_TYPE_NONE;
4578 s->gotit = FALSE;
4579 s->we_are_in = FALSE;
4580
4581 s->tried_pubkey_config = FALSE;
4582 s->tried_agent = FALSE;
4583 s->tried_keyb_inter = FALSE;
4584 s->kbd_inter_running = FALSE;
4585 /* Load the pub half of ssh->cfg.keyfile so we notice if it's in Pageant */
4586 if (!filename_is_null(ssh->cfg.keyfile)) {
4587 int keytype;
4588 logeventf(ssh, "Reading private key file \"%.150s\"",
4589 filename_to_str(&ssh->cfg.keyfile));
4590 keytype = key_type(&ssh->cfg.keyfile);
4591 if (keytype == SSH_KEYTYPE_SSH2) {
4592 s->publickey_blob =
4593 ssh2_userkey_loadpub(&ssh->cfg.keyfile, NULL,
4594 &s->publickey_bloblen, NULL);
4595 } else {
4596 char *msgbuf;
4597 logeventf(ssh, "Unable to use this key file (%s)",
4598 key_type_to_str(keytype));
4599 msgbuf = dupprintf("Unable to use key file \"%.150s\""
4600 " (%s)\r\n",
4601 filename_to_str(&ssh->cfg.keyfile),
4602 key_type_to_str(keytype));
4603 c_write_str(ssh, msgbuf);
4604 sfree(msgbuf);
4605 s->publickey_blob = NULL;
4606 }
4607 } else
4608 s->publickey_blob = NULL;
4609
4610 while (1) {
4611 /*
4612 * Wait for the result of the last authentication request.
4613 */
4614 if (!s->gotit)
4615 crWaitUntilV(ispkt);
4616 while (ssh->pktin.type == SSH2_MSG_USERAUTH_BANNER) {
4617 char *banner;
4618 int size;
4619 /*
4620 * Don't show the banner if we're operating in
4621 * non-verbose non-interactive mode. (It's probably
4622 * a script, which means nobody will read the
4623 * banner _anyway_, and moreover the printing of
4624 * the banner will screw up processing on the
4625 * output of (say) plink.)
4626 */
4627 if (flags & (FLAG_VERBOSE | FLAG_INTERACTIVE)) {
4628 ssh2_pkt_getstring(ssh, &banner, &size);
4629 if (banner)
4630 c_write_untrusted(ssh, banner, size);
4631 }
4632 crWaitUntilV(ispkt);
4633 }
4634 if (ssh->pktin.type == SSH2_MSG_USERAUTH_SUCCESS) {
4635 logevent("Access granted");
4636 s->we_are_in = TRUE;
4637 break;
4638 }
4639
4640 if (s->kbd_inter_running &&
4641 ssh->pktin.type == SSH2_MSG_USERAUTH_INFO_REQUEST) {
4642 /*
4643 * This is either a further set-of-prompts packet
4644 * in keyboard-interactive authentication, or it's
4645 * the same one and we came back here with `gotit'
4646 * set. In the former case, we must reset the
4647 * curr_prompt variable.
4648 */
4649 if (!s->gotit)
4650 s->curr_prompt = 0;
4651 } else if (ssh->pktin.type != SSH2_MSG_USERAUTH_FAILURE) {
4652 bombout(("Strange packet received during authentication: type %d",
4653 ssh->pktin.type));
4654 crStopV;
4655 }
4656
4657 s->gotit = FALSE;
4658
4659 /*
4660 * OK, we're now sitting on a USERAUTH_FAILURE message, so
4661 * we can look at the string in it and know what we can
4662 * helpfully try next.
4663 */
4664 if (ssh->pktin.type == SSH2_MSG_USERAUTH_FAILURE) {
4665 char *methods;
4666 int methlen;
4667 ssh2_pkt_getstring(ssh, &methods, &methlen);
4668 s->kbd_inter_running = FALSE;
4669 if (!ssh2_pkt_getbool(ssh)) {
4670 /*
4671 * We have received an unequivocal Access
4672 * Denied. This can translate to a variety of
4673 * messages:
4674 *
4675 * - if we'd just tried "none" authentication,
4676 * it's not worth printing anything at all
4677 *
4678 * - if we'd just tried a public key _offer_,
4679 * the message should be "Server refused our
4680 * key" (or no message at all if the key
4681 * came from Pageant)
4682 *
4683 * - if we'd just tried anything else, the
4684 * message really should be "Access denied".
4685 *
4686 * Additionally, if we'd just tried password
4687 * authentication, we should break out of this
4688 * whole loop so as to go back to the username
4689 * prompt.
4690 */
4691 if (s->type == AUTH_TYPE_NONE) {
4692 /* do nothing */
4693 } else if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD ||
4694 s->type == AUTH_TYPE_PUBLICKEY_OFFER_QUIET) {
4695 if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD)
4696 c_write_str(ssh, "Server refused our key\r\n");
4697 logevent("Server refused public key");
4698 } else if (s->type==AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET) {
4699 /* server declined keyboard-interactive; ignore */
4700 } else {
4701 c_write_str(ssh, "Access denied\r\n");
4702 logevent("Access denied");
4703 if (s->type == AUTH_TYPE_PASSWORD) {
4704 s->we_are_in = FALSE;
4705 break;
4706 }
4707 }
4708 } else {
4709 c_write_str(ssh, "Further authentication required\r\n");
4710 logevent("Further authentication required");
4711 }
4712
4713 s->can_pubkey =
4714 in_commasep_string("publickey", methods, methlen);
4715 s->can_passwd =
4716 in_commasep_string("password", methods, methlen);
4717 s->can_keyb_inter = ssh->cfg.try_ki_auth &&
4718 in_commasep_string("keyboard-interactive", methods, methlen);
4719 }
4720
4721 s->method = 0;
4722 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4723
4724 /*
4725 * Most password/passphrase prompts will be
4726 * non-echoing, so we set this to 0 by default.
4727 * Exception is that some keyboard-interactive prompts
4728 * can be echoing, in which case we'll set this to 1.
4729 */
4730 s->echo = 0;
4731
4732 if (!s->method && s->can_pubkey &&
4733 agent_exists() && !s->tried_agent) {
4734 /*
4735 * Attempt public-key authentication using Pageant.
4736 */
4737 void *r;
4738 s->authed = FALSE;
4739
4740 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4741 ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
4742
4743 s->tried_agent = TRUE;
4744
4745 logevent("Pageant is running. Requesting keys.");
4746
4747 /* Request the keys held by the agent. */
4748 PUT_32BIT(s->request, 1);
4749 s->request[4] = SSH2_AGENTC_REQUEST_IDENTITIES;
4750 if (!agent_query(s->request, 5, &r, &s->responselen,
4751 ssh_agent_callback, ssh)) {
4752 do {
4753 crReturnV;
4754 if (ispkt) {
4755 bombout(("Unexpected data from server while"
4756 " waiting for agent response"));
4757 crStopV;
4758 }
4759 } while (ispkt || inlen > 0);
4760 r = ssh->agent_response;
4761 s->responselen = ssh->agent_response_len;
4762 }
4763 s->response = (unsigned char *) r;
4764 if (s->response && s->responselen >= 5 &&
4765 s->response[4] == SSH2_AGENT_IDENTITIES_ANSWER) {
4766 s->p = s->response + 5;
4767 s->nkeys = GET_32BIT(s->p);
4768 s->p += 4;
4769 {
4770 char buf[64];
4771 sprintf(buf, "Pageant has %d SSH2 keys", s->nkeys);
4772 logevent(buf);
4773 }
4774 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
4775 void *vret;
4776
4777 {
4778 char buf[64];
4779 sprintf(buf, "Trying Pageant key #%d", s->keyi);
4780 logevent(buf);
4781 }
4782 s->pklen = GET_32BIT(s->p);
4783 s->p += 4;
4784 if (s->publickey_blob &&
4785 s->pklen == s->publickey_bloblen &&
4786 !memcmp(s->p, s->publickey_blob,
4787 s->publickey_bloblen)) {
4788 logevent("This key matches configured key file");
4789 s->tried_pubkey_config = 1;
4790 }
4791 s->pkblob = (char *)s->p;
4792 s->p += s->pklen;
4793 s->alglen = GET_32BIT(s->pkblob);
4794 s->alg = s->pkblob + 4;
4795 s->commentlen = GET_32BIT(s->p);
4796 s->p += 4;
4797 s->commentp = (char *)s->p;
4798 s->p += s->commentlen;
4799 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4800 ssh2_pkt_addstring(ssh, s->username);
4801 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4802 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4803 ssh2_pkt_addbool(ssh, FALSE); /* no signature included */
4804 ssh2_pkt_addstring_start(ssh);
4805 ssh2_pkt_addstring_data(ssh, s->alg, s->alglen);
4806 ssh2_pkt_addstring_start(ssh);
4807 ssh2_pkt_addstring_data(ssh, s->pkblob, s->pklen);
4808 ssh2_pkt_send(ssh);
4809
4810 crWaitUntilV(ispkt);
4811 if (ssh->pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
4812 logevent("Key refused");
4813 continue;
4814 }
4815
4816 if (flags & FLAG_VERBOSE) {
4817 c_write_str(ssh, "Authenticating with "
4818 "public key \"");
4819 c_write(ssh, s->commentp, s->commentlen);
4820 c_write_str(ssh, "\" from agent\r\n");
4821 }
4822
4823 /*
4824 * Server is willing to accept the key.
4825 * Construct a SIGN_REQUEST.
4826 */
4827 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4828 ssh2_pkt_addstring(ssh, s->username);
4829 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4830 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4831 ssh2_pkt_addbool(ssh, TRUE);
4832 ssh2_pkt_addstring_start(ssh);
4833 ssh2_pkt_addstring_data(ssh, s->alg, s->alglen);
4834 ssh2_pkt_addstring_start(ssh);
4835 ssh2_pkt_addstring_data(ssh, s->pkblob, s->pklen);
4836
4837 s->siglen = ssh->pktout.length - 5 + 4 + 20;
4838 if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
4839 s->siglen -= 4;
4840 s->len = 1; /* message type */
4841 s->len += 4 + s->pklen; /* key blob */
4842 s->len += 4 + s->siglen; /* data to sign */
4843 s->len += 4; /* flags */
4844 s->agentreq = snewn(4 + s->len, char);
4845 PUT_32BIT(s->agentreq, s->len);
4846 s->q = s->agentreq + 4;
4847 *s->q++ = SSH2_AGENTC_SIGN_REQUEST;
4848 PUT_32BIT(s->q, s->pklen);
4849 s->q += 4;
4850 memcpy(s->q, s->pkblob, s->pklen);
4851 s->q += s->pklen;
4852 PUT_32BIT(s->q, s->siglen);
4853 s->q += 4;
4854 /* Now the data to be signed... */
4855 if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
4856 PUT_32BIT(s->q, 20);
4857 s->q += 4;
4858 }
4859 memcpy(s->q, ssh->v2_session_id, 20);
4860 s->q += 20;
4861 memcpy(s->q, ssh->pktout.data + 5,
4862 ssh->pktout.length - 5);
4863 s->q += ssh->pktout.length - 5;
4864 /* And finally the (zero) flags word. */
4865 PUT_32BIT(s->q, 0);
4866 if (!agent_query(s->agentreq, s->len + 4,
4867 &vret, &s->retlen,
4868 ssh_agent_callback, ssh)) {
4869 do {
4870 crReturnV;
4871 if (ispkt) {
4872 bombout(("Unexpected data from server"
4873 " while waiting for agent"
4874 " response"));
4875 crStopV;
4876 }
4877 } while (ispkt || inlen > 0);
4878 vret = ssh->agent_response;
4879 s->retlen = ssh->agent_response_len;
4880 }
4881 s->ret = vret;
4882 sfree(s->agentreq);
4883 if (s->ret) {
4884 if (s->ret[4] == SSH2_AGENT_SIGN_RESPONSE) {
4885 logevent("Sending Pageant's response");
4886 ssh2_add_sigblob(ssh, s->pkblob, s->pklen,
4887 s->ret + 9,
4888 GET_32BIT(s->ret + 5));
4889 ssh2_pkt_send(ssh);
4890 s->authed = TRUE;
4891 break;
4892 } else {
4893 logevent
4894 ("Pageant failed to answer challenge");
4895 sfree(s->ret);
4896 }
4897 }
4898 }
4899 if (s->authed)
4900 continue;
4901 }
4902 }
4903
4904 if (!s->method && s->can_pubkey && s->publickey_blob
4905 && !s->tried_pubkey_config) {
4906 unsigned char *pub_blob;
4907 char *algorithm, *comment;
4908 int pub_blob_len;
4909
4910 s->tried_pubkey_config = TRUE;
4911
4912 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4913 ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
4914
4915 /*
4916 * Try the public key supplied in the configuration.
4917 *
4918 * First, offer the public blob to see if the server is
4919 * willing to accept it.
4920 */
4921 pub_blob =
4922 (unsigned char *)ssh2_userkey_loadpub(&ssh->cfg.keyfile,
4923 &algorithm,
4924 &pub_blob_len,
4925 NULL);
4926 if (pub_blob) {
4927 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4928 ssh2_pkt_addstring(ssh, s->username);
4929 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4930 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4931 ssh2_pkt_addbool(ssh, FALSE); /* no signature included */
4932 ssh2_pkt_addstring(ssh, algorithm);
4933 ssh2_pkt_addstring_start(ssh);
4934 ssh2_pkt_addstring_data(ssh, (char *)pub_blob,
4935 pub_blob_len);
4936 ssh2_pkt_send(ssh);
4937 logevent("Offered public key"); /* FIXME */
4938
4939 crWaitUntilV(ispkt);
4940 if (ssh->pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
4941 s->gotit = TRUE;
4942 s->type = AUTH_TYPE_PUBLICKEY_OFFER_LOUD;
4943 continue; /* key refused; give up on it */
4944 }
4945
4946 logevent("Offer of public key accepted");
4947 /*
4948 * Actually attempt a serious authentication using
4949 * the key.
4950 */
4951 if (ssh2_userkey_encrypted(&ssh->cfg.keyfile, &comment)) {
4952 sprintf(s->pwprompt,
4953 "Passphrase for key \"%.100s\": ",
4954 comment);
4955 s->need_pw = TRUE;
4956 } else {
4957 s->need_pw = FALSE;
4958 }
4959 c_write_str(ssh, "Authenticating with public key \"");
4960 c_write_str(ssh, comment);
4961 c_write_str(ssh, "\"\r\n");
4962 s->method = AUTH_PUBLICKEY_FILE;
4963 }
4964 }
4965
4966 if (!s->method && s->can_keyb_inter && !s->tried_keyb_inter) {
4967 s->method = AUTH_KEYBOARD_INTERACTIVE;
4968 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
4969 s->tried_keyb_inter = TRUE;
4970
4971 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4972 ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;
4973
4974 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4975 ssh2_pkt_addstring(ssh, s->username);
4976 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4977 ssh2_pkt_addstring(ssh, "keyboard-interactive"); /* method */
4978 ssh2_pkt_addstring(ssh, ""); /* lang */
4979 ssh2_pkt_addstring(ssh, "");
4980 ssh2_pkt_send(ssh);
4981
4982 crWaitUntilV(ispkt);
4983 if (ssh->pktin.type != SSH2_MSG_USERAUTH_INFO_REQUEST) {
4984 if (ssh->pktin.type == SSH2_MSG_USERAUTH_FAILURE)
4985 s->gotit = TRUE;
4986 logevent("Keyboard-interactive authentication refused");
4987 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET;
4988 continue;
4989 }
4990
4991 s->kbd_inter_running = TRUE;
4992 s->curr_prompt = 0;
4993 }
4994
4995 if (s->kbd_inter_running) {
4996 s->method = AUTH_KEYBOARD_INTERACTIVE;
4997 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
4998 s->tried_keyb_inter = TRUE;
4999
5000 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
5001 ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;
5002
5003 if (s->curr_prompt == 0) {
5004 /*
5005 * We've got a fresh USERAUTH_INFO_REQUEST.
5006 * Display header data, and start going through
5007 * the prompts.
5008 */
5009 char *name, *inst, *lang;
5010 int name_len, inst_len, lang_len;
5011
5012 ssh2_pkt_getstring(ssh, &name, &name_len);
5013 ssh2_pkt_getstring(ssh, &inst, &inst_len);
5014 ssh2_pkt_getstring(ssh, &lang, &lang_len);
5015 if (name_len > 0) {
5016 c_write_untrusted(ssh, name, name_len);
5017 c_write_str(ssh, "\r\n");
5018 }
5019 if (inst_len > 0) {
5020 c_write_untrusted(ssh, inst, inst_len);
5021 c_write_str(ssh, "\r\n");
5022 }
5023 s->num_prompts = ssh2_pkt_getuint32(ssh);
5024 }
5025
5026 /*
5027 * If there are prompts remaining in the packet,
5028 * display one and get a response.
5029 */
5030 if (s->curr_prompt < s->num_prompts) {
5031 char *prompt;
5032 int prompt_len;
5033
5034 ssh2_pkt_getstring(ssh, &prompt, &prompt_len);
5035 if (prompt_len > 0) {
5036 strncpy(s->pwprompt, prompt, sizeof(s->pwprompt));
5037 s->pwprompt[prompt_len < sizeof(s->pwprompt) ?
5038 prompt_len : sizeof(s->pwprompt)-1] = '\0';
5039 } else {
5040 strcpy(s->pwprompt,
5041 "<server failed to send prompt>: ");
5042 }
5043 s->echo = ssh2_pkt_getbool(ssh);
5044 s->need_pw = TRUE;
5045 } else
5046 s->need_pw = FALSE;
5047 }
5048
5049 if (!s->method && s->can_passwd) {
5050 s->method = AUTH_PASSWORD;
5051 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
5052 ssh->pkt_ctx |= SSH2_PKTCTX_PASSWORD;
5053 sprintf(s->pwprompt, "%.90s@%.90s's password: ", s->username,
5054 ssh->savedhost);
5055 s->need_pw = TRUE;
5056 }
5057
5058 if (s->need_pw) {
5059 if (ssh_get_line) {
5060 if (!ssh_get_line(s->pwprompt, s->password,
5061 sizeof(s->password), TRUE)) {
5062 /*
5063 * get_line failed to get a password (for
5064 * example because one was supplied on the
5065 * command line which has already failed to
5066 * work). Terminate.
5067 */
5068 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5069 ssh2_pkt_adduint32(ssh,SSH2_DISCONNECT_BY_APPLICATION);
5070 ssh2_pkt_addstring(ssh, "No more passwords available"
5071 " to try");
5072 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5073 ssh2_pkt_send(ssh);
5074 logevent("Unable to authenticate");
5075 connection_fatal(ssh->frontend,
5076 "Unable to authenticate");
5077 ssh_closing((Plug)ssh, NULL, 0, 0);
5078 crStopV;
5079 }
5080 } else {
5081 int ret; /* need not be saved across crReturn */
5082 c_write_untrusted(ssh, s->pwprompt, strlen(s->pwprompt));
5083 ssh->send_ok = 1;
5084
5085 setup_userpass_input(ssh, s->password,
5086 sizeof(s->password), s->echo);
5087 do {
5088 crWaitUntilV(!ispkt);
5089 ret = process_userpass_input(ssh, in, inlen);
5090 } while (ret == 0);
5091 if (ret < 0)
5092 cleanup_exit(0);
5093 c_write_str(ssh, "\r\n");
5094 }
5095 }
5096
5097 if (s->method == AUTH_PUBLICKEY_FILE) {
5098 /*
5099 * We have our passphrase. Now try the actual authentication.
5100 */
5101 struct ssh2_userkey *key;
5102 const char *error = NULL;
5103
5104 key = ssh2_load_userkey(&ssh->cfg.keyfile, s->password,
5105 &error);
5106 if (key == SSH2_WRONG_PASSPHRASE || key == NULL) {
5107 if (key == SSH2_WRONG_PASSPHRASE) {
5108 c_write_str(ssh, "Wrong passphrase\r\n");
5109 s->tried_pubkey_config = FALSE;
5110 } else {
5111 c_write_str(ssh, "Unable to load private key (");
5112 c_write_str(ssh, error);
5113 c_write_str(ssh, ")\r\n");
5114 s->tried_pubkey_config = TRUE;
5115 }
5116 /* Send a spurious AUTH_NONE to return to the top. */
5117 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
5118 ssh2_pkt_addstring(ssh, s->username);
5119 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
5120 ssh2_pkt_addstring(ssh, "none"); /* method */
5121 ssh2_pkt_send(ssh);
5122 s->type = AUTH_TYPE_NONE;
5123 } else {
5124 unsigned char *pkblob, *sigblob, *sigdata;
5125 int pkblob_len, sigblob_len, sigdata_len;
5126 int p;
5127
5128 /*
5129 * We have loaded the private key and the server
5130 * has announced that it's willing to accept it.
5131 * Hallelujah. Generate a signature and send it.
5132 */
5133 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
5134 ssh2_pkt_addstring(ssh, s->username);
5135 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
5136 ssh2_pkt_addstring(ssh, "publickey"); /* method */
5137 ssh2_pkt_addbool(ssh, TRUE);
5138 ssh2_pkt_addstring(ssh, key->alg->name);
5139 pkblob = key->alg->public_blob(key->data, &pkblob_len);
5140 ssh2_pkt_addstring_start(ssh);
5141 ssh2_pkt_addstring_data(ssh, (char *)pkblob, pkblob_len);
5142
5143 /*
5144 * The data to be signed is:
5145 *
5146 * string session-id
5147 *
5148 * followed by everything so far placed in the
5149 * outgoing packet.
5150 */
5151 sigdata_len = ssh->pktout.length - 5 + 4 + 20;
5152 if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
5153 sigdata_len -= 4;
5154 sigdata = snewn(sigdata_len, unsigned char);
5155 p = 0;
5156 if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
5157 PUT_32BIT(sigdata+p, 20);
5158 p += 4;
5159 }
5160 memcpy(sigdata+p, ssh->v2_session_id, 20); p += 20;
5161 memcpy(sigdata+p, ssh->pktout.data + 5,
5162 ssh->pktout.length - 5);
5163 p += ssh->pktout.length - 5;
5164 assert(p == sigdata_len);
5165 sigblob = key->alg->sign(key->data, (char *)sigdata,
5166 sigdata_len, &sigblob_len);
5167 ssh2_add_sigblob(ssh, pkblob, pkblob_len,
5168 sigblob, sigblob_len);
5169 sfree(pkblob);
5170 sfree(sigblob);
5171 sfree(sigdata);
5172
5173 ssh2_pkt_send(ssh);
5174 s->type = AUTH_TYPE_PUBLICKEY;
5175 }
5176 } else if (s->method == AUTH_PASSWORD) {
5177 /*
5178 * We send the password packet lumped tightly together with
5179 * an SSH_MSG_IGNORE packet. The IGNORE packet contains a
5180 * string long enough to make the total length of the two
5181 * packets constant. This should ensure that a passive
5182 * listener doing traffic analyis can't work out the length
5183 * of the password.
5184 *
5185 * For this to work, we need an assumption about the
5186 * maximum length of the password packet. I think 256 is
5187 * pretty conservative. Anyone using a password longer than
5188 * that probably doesn't have much to worry about from
5189 * people who find out how long their password is!
5190 */
5191 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
5192 ssh2_pkt_addstring(ssh, s->username);
5193 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
5194 ssh2_pkt_addstring(ssh, "password");
5195 ssh2_pkt_addbool(ssh, FALSE);
5196 ssh2_pkt_addstring(ssh, s->password);
5197 memset(s->password, 0, sizeof(s->password));
5198 ssh2_pkt_defer(ssh);
5199 /*
5200 * We'll include a string that's an exact multiple of the
5201 * cipher block size. If the cipher is NULL for some
5202 * reason, we don't do this trick at all because we gain
5203 * nothing by it.
5204 */
5205 if (ssh->cscipher) {
5206 int stringlen, i;
5207
5208 stringlen = (256 - ssh->deferred_len);
5209 stringlen += ssh->cscipher->blksize - 1;
5210 stringlen -= (stringlen % ssh->cscipher->blksize);
5211 if (ssh->cscomp) {
5212 /*
5213 * Temporarily disable actual compression,
5214 * so we can guarantee to get this string
5215 * exactly the length we want it. The
5216 * compression-disabling routine should
5217 * return an integer indicating how many
5218 * bytes we should adjust our string length
5219 * by.
5220 */
5221 stringlen -=
5222 ssh->cscomp->disable_compression(ssh->cs_comp_ctx);
5223 }
5224 ssh2_pkt_init(ssh, SSH2_MSG_IGNORE);
5225 ssh2_pkt_addstring_start(ssh);
5226 for (i = 0; i < stringlen; i++) {
5227 char c = (char) random_byte();
5228 ssh2_pkt_addstring_data(ssh, &c, 1);
5229 }
5230 ssh2_pkt_defer(ssh);
5231 }
5232 ssh_pkt_defersend(ssh);
5233 logevent("Sent password");
5234 s->type = AUTH_TYPE_PASSWORD;
5235 } else if (s->method == AUTH_KEYBOARD_INTERACTIVE) {
5236 if (s->curr_prompt == 0) {
5237 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_INFO_RESPONSE);
5238 ssh2_pkt_adduint32(ssh, s->num_prompts);
5239 }
5240 if (s->need_pw) { /* only add pw if we just got one! */
5241 ssh2_pkt_addstring(ssh, s->password);
5242 memset(s->password, 0, sizeof(s->password));
5243 s->curr_prompt++;
5244 }
5245 if (s->curr_prompt >= s->num_prompts) {
5246 ssh2_pkt_send(ssh);
5247 } else {
5248 /*
5249 * If there are prompts remaining, we set
5250 * `gotit' so that we won't attempt to get
5251 * another packet. Then we go back round the
5252 * loop and will end up retrieving another
5253 * prompt out of the existing packet. Funky or
5254 * what?
5255 */
5256 s->gotit = TRUE;
5257 }
5258 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
5259 } else {
5260 c_write_str(ssh, "No supported authentication methods"
5261 " left to try!\r\n");
5262 logevent("No supported authentications offered."
5263 " Disconnecting");
5264 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5265 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5266 ssh2_pkt_addstring(ssh, "No supported authentication"
5267 " methods available");
5268 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5269 ssh2_pkt_send(ssh);
5270 ssh_closing((Plug)ssh, NULL, 0, 0);
5271 crStopV;
5272 }
5273 }
5274 } while (!s->we_are_in);
5275
5276 /*
5277 * Now we're authenticated for the connection protocol. The
5278 * connection protocol will automatically have started at this
5279 * point; there's no need to send SERVICE_REQUEST.
5280 */
5281
5282 /*
5283 * So now create a channel with a session in it.
5284 */
5285 ssh->channels = newtree234(ssh_channelcmp);
5286 ssh->mainchan = snew(struct ssh_channel);
5287 ssh->mainchan->ssh = ssh;
5288 ssh->mainchan->localid = alloc_channel_id(ssh);
5289 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN);
5290 ssh2_pkt_addstring(ssh, "session");
5291 ssh2_pkt_adduint32(ssh, ssh->mainchan->localid);
5292 ssh->mainchan->v.v2.locwindow = OUR_V2_WINSIZE;
5293 ssh2_pkt_adduint32(ssh, ssh->mainchan->v.v2.locwindow);/* our window size */
5294 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
5295 ssh2_pkt_send(ssh);
5296 crWaitUntilV(ispkt);
5297 if (ssh->pktin.type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
5298 bombout(("Server refused to open a session"));
5299 crStopV;
5300 /* FIXME: error data comes back in FAILURE packet */
5301 }
5302 if (ssh2_pkt_getuint32(ssh) != ssh->mainchan->localid) {
5303 bombout(("Server's channel confirmation cited wrong channel"));
5304 crStopV;
5305 }
5306 ssh->mainchan->remoteid = ssh2_pkt_getuint32(ssh);
5307 ssh->mainchan->type = CHAN_MAINSESSION;
5308 ssh->mainchan->closes = 0;
5309 ssh->mainchan->v.v2.remwindow = ssh2_pkt_getuint32(ssh);
5310 ssh->mainchan->v.v2.remmaxpkt = ssh2_pkt_getuint32(ssh);
5311 bufchain_init(&ssh->mainchan->v.v2.outbuffer);
5312 add234(ssh->channels, ssh->mainchan);
5313 logevent("Opened channel for session");
5314
5315 /*
5316 * Potentially enable X11 forwarding.
5317 */
5318 if (ssh->cfg.x11_forward) {
5319 char proto[20], data[64];
5320 logevent("Requesting X11 forwarding");
5321 ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
5322 data, sizeof(data), ssh->cfg.x11_auth);
5323 x11_get_real_auth(ssh->x11auth, ssh->cfg.x11_display);
5324 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5325 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
5326 ssh2_pkt_addstring(ssh, "x11-req");
5327 ssh2_pkt_addbool(ssh, 1); /* want reply */
5328 ssh2_pkt_addbool(ssh, 0); /* many connections */
5329 ssh2_pkt_addstring(ssh, proto);
5330 ssh2_pkt_addstring(ssh, data);
5331 ssh2_pkt_adduint32(ssh, x11_get_screen_number(ssh->cfg.x11_display));
5332 ssh2_pkt_send(ssh);
5333
5334 do {
5335 crWaitUntilV(ispkt);
5336 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5337 unsigned i = ssh2_pkt_getuint32(ssh);
5338 struct ssh_channel *c;
5339 c = find234(ssh->channels, &i, ssh_channelfind);
5340 if (!c)
5341 continue; /* nonexistent channel */
5342 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5343 }
5344 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5345
5346 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5347 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5348 bombout(("Unexpected response to X11 forwarding request:"
5349 " packet type %d", ssh->pktin.type));
5350 crStopV;
5351 }
5352 logevent("X11 forwarding refused");
5353 } else {
5354 logevent("X11 forwarding enabled");
5355 ssh->X11_fwd_enabled = TRUE;
5356 }
5357 }
5358
5359 /*
5360 * Enable port forwardings.
5361 */
5362 {
5363 char type;
5364 int n;
5365 int sport,dport,sserv,dserv;
5366 char sports[256], dports[256], saddr[256], host[256];
5367
5368 ssh->rportfwds = newtree234(ssh_rportcmp_ssh2);
5369 /* Add port forwardings. */
5370 ssh->portfwd_strptr = ssh->cfg.portfwd;
5371 while (*ssh->portfwd_strptr) {
5372 type = *ssh->portfwd_strptr++;
5373 saddr[0] = '\0';
5374 n = 0;
5375 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != '\t') {
5376 if (*ssh->portfwd_strptr == ':') {
5377 /*
5378 * We've seen a colon in the middle of the
5379 * source port number. This means that
5380 * everything we've seen until now is the
5381 * source _address_, so we'll move it into
5382 * saddr and start sports from the beginning
5383 * again.
5384 */
5385 ssh->portfwd_strptr++;
5386 sports[n] = '\0';
5387 strcpy(saddr, sports);
5388 n = 0;
5389 }
5390 if (n < 255) sports[n++] = *ssh->portfwd_strptr++;
5391 }
5392 sports[n] = 0;
5393 if (type != 'D') {
5394 if (*ssh->portfwd_strptr == '\t')
5395 ssh->portfwd_strptr++;
5396 n = 0;
5397 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':') {
5398 if (n < 255) host[n++] = *ssh->portfwd_strptr++;
5399 }
5400 host[n] = 0;
5401 if (*ssh->portfwd_strptr == ':')
5402 ssh->portfwd_strptr++;
5403 n = 0;
5404 while (*ssh->portfwd_strptr) {
5405 if (n < 255) dports[n++] = *ssh->portfwd_strptr++;
5406 }
5407 dports[n] = 0;
5408 ssh->portfwd_strptr++;
5409 dport = atoi(dports);
5410 dserv = 0;
5411 if (dport == 0) {
5412 dserv = 1;
5413 dport = net_service_lookup(dports);
5414 if (!dport) {
5415 logeventf(ssh, "Service lookup failed for destination"
5416 " port \"%s\"", dports);
5417 }
5418 }
5419 } else {
5420 while (*ssh->portfwd_strptr) ssh->portfwd_strptr++;
5421 dport = dserv = -1;
5422 ssh->portfwd_strptr++; /* eat the NUL and move to next one */
5423 }
5424 sport = atoi(sports);
5425 sserv = 0;
5426 if (sport == 0) {
5427 sserv = 1;
5428 sport = net_service_lookup(sports);
5429 if (!sport) {
5430 logeventf(ssh, "Service lookup failed for source"
5431 " port \"%s\"", sports);
5432 }
5433 }
5434 if (sport && dport) {
5435 if (type == 'L') {
5436 pfd_addforward(host, dport, *saddr ? saddr : NULL,
5437 sport, ssh, &ssh->cfg);
5438 logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
5439 " forwarding to %s:%.*s%.*s%d%.*s",
5440 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
5441 (int)(*saddr?1:0), ":",
5442 (int)(sserv ? strlen(sports) : 0), sports,
5443 sserv, "(", sport, sserv, ")",
5444 host,
5445 (int)(dserv ? strlen(dports) : 0), dports,
5446 dserv, "(", dport, dserv, ")");
5447 } else if (type == 'D') {
5448 pfd_addforward(NULL, -1, *saddr ? saddr : NULL,
5449 sport, ssh, &ssh->cfg);
5450 logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
5451 " doing SOCKS dynamic forwarding",
5452 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
5453 (int)(*saddr?1:0), ":",
5454 (int)(sserv ? strlen(sports) : 0), sports,
5455 sserv, "(", sport, sserv, ")");
5456 } else {
5457 struct ssh_rportfwd *pf;
5458 pf = snew(struct ssh_rportfwd);
5459 strcpy(pf->dhost, host);
5460 pf->dport = dport;
5461 pf->sport = sport;
5462 if (add234(ssh->rportfwds, pf) != pf) {
5463 logeventf(ssh, "Duplicate remote port forwarding"
5464 " to %s:%d", host, dport);
5465 sfree(pf);
5466 } else {
5467 logeventf(ssh, "Requesting remote port "
5468 "%.*s%.*s%.*s%.*s%d%.*s"
5469 " forward to %s:%.*s%.*s%d%.*s",
5470 (int)(*saddr?strlen(saddr):0),
5471 *saddr?saddr:NULL,
5472 (int)(*saddr?1:0), ":",
5473 (int)(sserv ? strlen(sports) : 0), sports,
5474 sserv, "(", sport, sserv, ")",
5475 host,
5476 (int)(dserv ? strlen(dports) : 0), dports,
5477 dserv, "(", dport, dserv, ")");
5478 ssh2_pkt_init(ssh, SSH2_MSG_GLOBAL_REQUEST);
5479 ssh2_pkt_addstring(ssh, "tcpip-forward");
5480 ssh2_pkt_addbool(ssh, 1);/* want reply */
5481 if (*saddr)
5482 ssh2_pkt_addstring(ssh, saddr);
5483 if (ssh->cfg.rport_acceptall)
5484 ssh2_pkt_addstring(ssh, "0.0.0.0");
5485 else
5486 ssh2_pkt_addstring(ssh, "127.0.0.1");
5487 ssh2_pkt_adduint32(ssh, sport);
5488 ssh2_pkt_send(ssh);
5489
5490 do {
5491 crWaitUntilV(ispkt);
5492 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5493 unsigned i = ssh2_pkt_getuint32(ssh);
5494 struct ssh_channel *c;
5495 c = find234(ssh->channels, &i, ssh_channelfind);
5496 if (!c)
5497 continue;/* nonexistent channel */
5498 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5499 }
5500 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5501
5502 if (ssh->pktin.type != SSH2_MSG_REQUEST_SUCCESS) {
5503 if (ssh->pktin.type != SSH2_MSG_REQUEST_FAILURE) {
5504 bombout(("Unexpected response to port "
5505 "forwarding request: packet type %d",
5506 ssh->pktin.type));
5507 crStopV;
5508 }
5509 logevent("Server refused this port forwarding");
5510 } else {
5511 logevent("Remote port forwarding enabled");
5512 }
5513 }
5514 }
5515 }
5516 }
5517 }
5518
5519 /*
5520 * Potentially enable agent forwarding.
5521 */
5522 if (ssh->cfg.agentfwd && agent_exists()) {
5523 logevent("Requesting OpenSSH-style agent forwarding");
5524 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5525 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
5526 ssh2_pkt_addstring(ssh, "auth-agent-req@openssh.com");
5527 ssh2_pkt_addbool(ssh, 1); /* want reply */
5528 ssh2_pkt_send(ssh);
5529
5530 do {
5531 crWaitUntilV(ispkt);
5532 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5533 unsigned i = ssh2_pkt_getuint32(ssh);
5534 struct ssh_channel *c;
5535 c = find234(ssh->channels, &i, ssh_channelfind);
5536 if (!c)
5537 continue; /* nonexistent channel */
5538 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5539 }
5540 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5541
5542 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5543 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5544 bombout(("Unexpected response to agent forwarding request:"
5545 " packet type %d", ssh->pktin.type));
5546 crStopV;
5547 }
5548 logevent("Agent forwarding refused");
5549 } else {
5550 logevent("Agent forwarding enabled");
5551 ssh->agentfwd_enabled = TRUE;
5552 }
5553 }
5554
5555 /*
5556 * Now allocate a pty for the session.
5557 */
5558 if (!ssh->cfg.nopty) {
5559 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5560 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid); /* recipient channel */
5561 ssh2_pkt_addstring(ssh, "pty-req");
5562 ssh2_pkt_addbool(ssh, 1); /* want reply */
5563 ssh2_pkt_addstring(ssh, ssh->cfg.termtype);
5564 ssh2_pkt_adduint32(ssh, ssh->term_width);
5565 ssh2_pkt_adduint32(ssh, ssh->term_height);
5566 ssh2_pkt_adduint32(ssh, 0); /* pixel width */
5567 ssh2_pkt_adduint32(ssh, 0); /* pixel height */
5568 ssh2_pkt_addstring_start(ssh);
5569 ssh2_pkt_addstring_data(ssh, "\0", 1); /* TTY_OP_END, no special options */
5570 ssh2_pkt_send(ssh);
5571 ssh->state = SSH_STATE_INTERMED;
5572
5573 do {
5574 crWaitUntilV(ispkt);
5575 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5576 unsigned i = ssh2_pkt_getuint32(ssh);
5577 struct ssh_channel *c;
5578 c = find234(ssh->channels, &i, ssh_channelfind);
5579 if (!c)
5580 continue; /* nonexistent channel */
5581 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5582 }
5583 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5584
5585 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5586 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5587 bombout(("Unexpected response to pty request:"
5588 " packet type %d", ssh->pktin.type));
5589 crStopV;
5590 }
5591 c_write_str(ssh, "Server refused to allocate pty\r\n");
5592 ssh->editing = ssh->echoing = 1;
5593 } else {
5594 logevent("Allocated pty");
5595 }
5596 } else {
5597 ssh->editing = ssh->echoing = 1;
5598 }
5599
5600 /*
5601 * Start a shell or a remote command. We may have to attempt
5602 * this twice if the config data has provided a second choice
5603 * of command.
5604 */
5605 while (1) {
5606 int subsys;
5607 char *cmd;
5608
5609 if (ssh->fallback_cmd) {
5610 subsys = ssh->cfg.ssh_subsys2;
5611 cmd = ssh->cfg.remote_cmd_ptr2;
5612 } else {
5613 subsys = ssh->cfg.ssh_subsys;
5614 cmd = ssh->cfg.remote_cmd_ptr;
5615 }
5616
5617 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5618 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid); /* recipient channel */
5619 if (subsys) {
5620 ssh2_pkt_addstring(ssh, "subsystem");
5621 ssh2_pkt_addbool(ssh, 1); /* want reply */
5622 ssh2_pkt_addstring(ssh, cmd);
5623 } else if (*cmd) {
5624 ssh2_pkt_addstring(ssh, "exec");
5625 ssh2_pkt_addbool(ssh, 1); /* want reply */
5626 ssh2_pkt_addstring(ssh, cmd);
5627 } else {
5628 ssh2_pkt_addstring(ssh, "shell");
5629 ssh2_pkt_addbool(ssh, 1); /* want reply */
5630 }
5631 ssh2_pkt_send(ssh);
5632 do {
5633 crWaitUntilV(ispkt);
5634 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5635 unsigned i = ssh2_pkt_getuint32(ssh);
5636 struct ssh_channel *c;
5637 c = find234(ssh->channels, &i, ssh_channelfind);
5638 if (!c)
5639 continue; /* nonexistent channel */
5640 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5641 }
5642 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5643 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5644 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5645 bombout(("Unexpected response to shell/command request:"
5646 " packet type %d", ssh->pktin.type));
5647 crStopV;
5648 }
5649 /*
5650 * We failed to start the command. If this is the
5651 * fallback command, we really are finished; if it's
5652 * not, and if the fallback command exists, try falling
5653 * back to it before complaining.
5654 */
5655 if (!ssh->fallback_cmd && ssh->cfg.remote_cmd_ptr2 != NULL) {
5656 logevent("Primary command failed; attempting fallback");
5657 ssh->fallback_cmd = TRUE;
5658 continue;
5659 }
5660 bombout(("Server refused to start a shell/command"));
5661 crStopV;
5662 } else {
5663 logevent("Started a shell/command");
5664 }
5665 break;
5666 }
5667
5668 ssh->state = SSH_STATE_SESSION;
5669 if (ssh->size_needed)
5670 ssh_size(ssh, ssh->term_width, ssh->term_height);
5671 if (ssh->eof_needed)
5672 ssh_special(ssh, TS_EOF);
5673
5674 /*
5675 * Transfer data!
5676 */
5677 if (ssh->ldisc)
5678 ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */
5679 ssh->send_ok = 1;
5680 while (1) {
5681 crReturnV;
5682 s->try_send = FALSE;
5683 if (ispkt) {
5684 if (ssh->pktin.type == SSH2_MSG_CHANNEL_DATA ||
5685 ssh->pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA) {
5686 char *data;
5687 int length;
5688 unsigned i = ssh2_pkt_getuint32(ssh);
5689 struct ssh_channel *c;
5690 c = find234(ssh->channels, &i, ssh_channelfind);
5691 if (!c)
5692 continue; /* nonexistent channel */
5693 if (ssh->pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
5694 ssh2_pkt_getuint32(ssh) != SSH2_EXTENDED_DATA_STDERR)
5695 continue; /* extended but not stderr */
5696 ssh2_pkt_getstring(ssh, &data, &length);
5697 if (data) {
5698 int bufsize = 0;
5699 c->v.v2.locwindow -= length;
5700 switch (c->type) {
5701 case CHAN_MAINSESSION:
5702 bufsize =
5703 from_backend(ssh->frontend, ssh->pktin.type ==
5704 SSH2_MSG_CHANNEL_EXTENDED_DATA,
5705 data, length);
5706 break;
5707 case CHAN_X11:
5708 bufsize = x11_send(c->u.x11.s, data, length);
5709 break;
5710 case CHAN_SOCKDATA:
5711 bufsize = pfd_send(c->u.pfd.s, data, length);
5712 break;
5713 case CHAN_AGENT:
5714 while (length > 0) {
5715 if (c->u.a.lensofar < 4) {
5716 int l = min(4 - c->u.a.lensofar, length);
5717 memcpy(c->u.a.msglen + c->u.a.lensofar,
5718 data, l);
5719 data += l;
5720 length -= l;
5721 c->u.a.lensofar += l;
5722 }
5723 if (c->u.a.lensofar == 4) {
5724 c->u.a.totallen =
5725 4 + GET_32BIT(c->u.a.msglen);
5726 c->u.a.message = snewn(c->u.a.totallen,
5727 unsigned char);
5728 memcpy(c->u.a.message, c->u.a.msglen, 4);
5729 }
5730 if (c->u.a.lensofar >= 4 && length > 0) {
5731 int l =
5732 min(c->u.a.totallen - c->u.a.lensofar,
5733 length);
5734 memcpy(c->u.a.message + c->u.a.lensofar,
5735 data, l);
5736 data += l;
5737 length -= l;
5738 c->u.a.lensofar += l;
5739 }
5740 if (c->u.a.lensofar == c->u.a.totallen) {
5741 void *reply;
5742 int replylen;
5743 if (agent_query(c->u.a.message,
5744 c->u.a.totallen,
5745 &reply, &replylen,
5746 ssh_agentf_callback, c))
5747 ssh_agentf_callback(c, reply, replylen);
5748 sfree(c->u.a.message);
5749 c->u.a.lensofar = 0;
5750 }
5751 }
5752 bufsize = 0;
5753 break;
5754 }
5755 /*
5756 * If we are not buffering too much data,
5757 * enlarge the window again at the remote side.
5758 */
5759 if (bufsize < OUR_V2_WINSIZE)
5760 ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
5761 }
5762 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_EOF) {
5763 unsigned i = ssh2_pkt_getuint32(ssh);
5764 struct ssh_channel *c;
5765
5766 c = find234(ssh->channels, &i, ssh_channelfind);
5767 if (!c)
5768 continue; /* nonexistent channel */
5769
5770 if (c->type == CHAN_X11) {
5771 /*
5772 * Remote EOF on an X11 channel means we should
5773 * wrap up and close the channel ourselves.
5774 */
5775 x11_close(c->u.x11.s);
5776 sshfwd_close(c);
5777 } else if (c->type == CHAN_AGENT) {
5778 sshfwd_close(c);
5779 } else if (c->type == CHAN_SOCKDATA) {
5780 pfd_close(c->u.pfd.s);
5781 sshfwd_close(c);
5782 }
5783 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_CLOSE) {
5784 unsigned i = ssh2_pkt_getuint32(ssh);
5785 struct ssh_channel *c;
5786
5787 c = find234(ssh->channels, &i, ssh_channelfind);
5788 if (!c || ((int)c->remoteid) == -1) {
5789 bombout(("Received CHANNEL_CLOSE for %s channel %d\n",
5790 c ? "half-open" : "nonexistent", i));
5791 crStopV;
5792 }
5793 /* Do pre-close processing on the channel. */
5794 switch (c->type) {
5795 case CHAN_MAINSESSION:
5796 break; /* nothing to see here, move along */
5797 case CHAN_X11:
5798 if (c->u.x11.s != NULL)
5799 x11_close(c->u.x11.s);
5800 sshfwd_close(c);
5801 break;
5802 case CHAN_AGENT:
5803 sshfwd_close(c);
5804 break;
5805 case CHAN_SOCKDATA:
5806 if (c->u.pfd.s != NULL)
5807 pfd_close(c->u.pfd.s);
5808 sshfwd_close(c);
5809 break;
5810 }
5811 if (c->closes == 0) {
5812 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
5813 ssh2_pkt_adduint32(ssh, c->remoteid);
5814 ssh2_pkt_send(ssh);
5815 }
5816 del234(ssh->channels, c);
5817 bufchain_clear(&c->v.v2.outbuffer);
5818 sfree(c);
5819
5820 /*
5821 * See if that was the last channel left open.
5822 */
5823 if (count234(ssh->channels) == 0) {
5824 logevent("All channels closed. Disconnecting");
5825 #if 0
5826 /*
5827 * We used to send SSH_MSG_DISCONNECT here,
5828 * because I'd believed that _every_ conforming
5829 * SSH2 connection had to end with a disconnect
5830 * being sent by at least one side; apparently
5831 * I was wrong and it's perfectly OK to
5832 * unceremoniously slam the connection shut
5833 * when you're done, and indeed OpenSSH feels
5834 * this is more polite than sending a
5835 * DISCONNECT. So now we don't.
5836 */
5837 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5838 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5839 ssh2_pkt_addstring(ssh, "All open channels closed");
5840 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5841 ssh2_pkt_send(ssh);
5842 #endif
5843 ssh_closing((Plug)ssh, NULL, 0, 0);
5844 crStopV;
5845 }
5846 continue; /* remote sends close; ignore (FIXME) */
5847 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5848 unsigned i = ssh2_pkt_getuint32(ssh);
5849 struct ssh_channel *c;
5850 c = find234(ssh->channels, &i, ssh_channelfind);
5851 if (!c || c->closes)
5852 continue; /* nonexistent or closing channel */
5853 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5854 s->try_send = TRUE;
5855 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
5856 unsigned i = ssh2_pkt_getuint32(ssh);
5857 struct ssh_channel *c;
5858 c = find234(ssh->channels, &i, ssh_channelfind);
5859 if (!c)
5860 continue; /* nonexistent channel */
5861 if (c->type != CHAN_SOCKDATA_DORMANT)
5862 continue; /* dunno why they're confirming this */
5863 c->remoteid = ssh2_pkt_getuint32(ssh);
5864 c->type = CHAN_SOCKDATA;
5865 c->v.v2.remwindow = ssh2_pkt_getuint32(ssh);
5866 c->v.v2.remmaxpkt = ssh2_pkt_getuint32(ssh);
5867 if (c->u.pfd.s)
5868 pfd_confirm(c->u.pfd.s);
5869 if (c->closes) {
5870 /*
5871 * We have a pending close on this channel,
5872 * which we decided on before the server acked
5873 * the channel open. So now we know the
5874 * remoteid, we can close it again.
5875 */
5876 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
5877 ssh2_pkt_adduint32(ssh, c->remoteid);
5878 ssh2_pkt_send(ssh);
5879 }
5880 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN_FAILURE) {
5881 unsigned i = ssh2_pkt_getuint32(ssh);
5882 struct ssh_channel *c;
5883 c = find234(ssh->channels, &i, ssh_channelfind);
5884 if (!c)
5885 continue; /* nonexistent channel */
5886 if (c->type != CHAN_SOCKDATA_DORMANT)
5887 continue; /* dunno why they're failing this */
5888
5889 logevent("Forwarded connection refused by server");
5890
5891 pfd_close(c->u.pfd.s);
5892
5893 del234(ssh->channels, c);
5894 sfree(c);
5895 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_REQUEST) {
5896 unsigned localid;
5897 char *type;
5898 int typelen, want_reply;
5899 struct ssh_channel *c;
5900
5901 localid = ssh2_pkt_getuint32(ssh);
5902 ssh2_pkt_getstring(ssh, &type, &typelen);
5903 want_reply = ssh2_pkt_getbool(ssh);
5904
5905 /*
5906 * First, check that the channel exists. Otherwise,
5907 * we can instantly disconnect with a rude message.
5908 */
5909 c = find234(ssh->channels, &localid, ssh_channelfind);
5910 if (!c) {
5911 char buf[80];
5912 sprintf(buf, "Received channel request for nonexistent"
5913 " channel %d", localid);
5914 logevent(buf);
5915 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5916 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5917 ssh2_pkt_addstring(ssh, buf);
5918 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5919 ssh2_pkt_send(ssh);
5920 connection_fatal(ssh->frontend, "%s", buf);
5921 ssh_closing((Plug)ssh, NULL, 0, 0);
5922 crStopV;
5923 }
5924
5925 /*
5926 * Having got the channel number, we now look at
5927 * the request type string to see if it's something
5928 * we recognise.
5929 */
5930 if (typelen == 11 && !memcmp(type, "exit-status", 11) &&
5931 c == ssh->mainchan) {
5932 /* We recognise "exit-status" on the primary channel. */
5933 char buf[100];
5934 ssh->exitcode = ssh2_pkt_getuint32(ssh);
5935 sprintf(buf, "Server sent command exit status %d",
5936 ssh->exitcode);
5937 logevent(buf);
5938 if (want_reply) {
5939 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_SUCCESS);
5940 ssh2_pkt_adduint32(ssh, c->remoteid);
5941 ssh2_pkt_send(ssh);
5942 }
5943 } else {
5944 /*
5945 * This is a channel request we don't know
5946 * about, so we now either ignore the request
5947 * or respond with CHANNEL_FAILURE, depending
5948 * on want_reply.
5949 */
5950 if (want_reply) {
5951 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_FAILURE);
5952 ssh2_pkt_adduint32(ssh, c->remoteid);
5953 ssh2_pkt_send(ssh);
5954 }
5955 }
5956 } else if (ssh->pktin.type == SSH2_MSG_GLOBAL_REQUEST) {
5957 char *type;
5958 int typelen, want_reply;
5959
5960 ssh2_pkt_getstring(ssh, &type, &typelen);
5961 want_reply = ssh2_pkt_getbool(ssh);
5962
5963 /*
5964 * We currently don't support any global requests
5965 * at all, so we either ignore the request or
5966 * respond with REQUEST_FAILURE, depending on
5967 * want_reply.
5968 */
5969 if (want_reply) {
5970 ssh2_pkt_init(ssh, SSH2_MSG_REQUEST_FAILURE);
5971 ssh2_pkt_send(ssh);
5972 }
5973 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN) {
5974 char *type;
5975 int typelen;
5976 char *peeraddr;
5977 int peeraddrlen;
5978 int peerport;
5979 char *error = NULL;
5980 struct ssh_channel *c;
5981 unsigned remid, winsize, pktsize;
5982 ssh2_pkt_getstring(ssh, &type, &typelen);
5983 c = snew(struct ssh_channel);
5984 c->ssh = ssh;
5985
5986 remid = ssh2_pkt_getuint32(ssh);
5987 winsize = ssh2_pkt_getuint32(ssh);
5988 pktsize = ssh2_pkt_getuint32(ssh);
5989
5990 if (typelen == 3 && !memcmp(type, "x11", 3)) {
5991 char *addrstr;
5992
5993 ssh2_pkt_getstring(ssh, &peeraddr, &peeraddrlen);
5994 addrstr = snewn(peeraddrlen+1, char);
5995 memcpy(addrstr, peeraddr, peeraddrlen);
5996 peeraddr[peeraddrlen] = '\0';
5997 peerport = ssh2_pkt_getuint32(ssh);
5998
5999 if (!ssh->X11_fwd_enabled)
6000 error = "X11 forwarding is not enabled";
6001 else if (x11_init(&c->u.x11.s, ssh->cfg.x11_display, c,
6002 ssh->x11auth, addrstr, peerport,
6003 &ssh->cfg) != NULL) {
6004 error = "Unable to open an X11 connection";
6005 } else {
6006 c->type = CHAN_X11;
6007 }
6008
6009 sfree(addrstr);
6010 } else if (typelen == 15 &&
6011 !memcmp(type, "forwarded-tcpip", 15)) {
6012 struct ssh_rportfwd pf, *realpf;
6013 char *dummy;
6014 int dummylen;
6015 ssh2_pkt_getstring(ssh, &dummy, &dummylen);/* skip address */
6016 pf.sport = ssh2_pkt_getuint32(ssh);
6017 ssh2_pkt_getstring(ssh, &peeraddr, &peeraddrlen);
6018 peerport = ssh2_pkt_getuint32(ssh);
6019 realpf = find234(ssh->rportfwds, &pf, NULL);
6020 if (realpf == NULL) {
6021 error = "Remote port is not recognised";
6022 } else {
6023 const char *e = pfd_newconnect(&c->u.pfd.s,
6024 realpf->dhost,
6025 realpf->dport, c,
6026 &ssh->cfg);
6027 logeventf(ssh, "Received remote port open request"
6028 " for %s:%d", realpf->dhost, realpf->dport);
6029 if (e != NULL) {
6030 logeventf(ssh, "Port open failed: %s", e);
6031 error = "Port open failed";
6032 } else {
6033 logevent("Forwarded port opened successfully");
6034 c->type = CHAN_SOCKDATA;
6035 }
6036 }
6037 } else if (typelen == 22 &&
6038 !memcmp(type, "auth-agent@openssh.com", 3)) {
6039 if (!ssh->agentfwd_enabled)
6040 error = "Agent forwarding is not enabled";
6041 else {
6042 c->type = CHAN_AGENT; /* identify channel type */
6043 c->u.a.lensofar = 0;
6044 }
6045 } else {
6046 error = "Unsupported channel type requested";
6047 }
6048
6049 c->remoteid = remid;
6050 if (error) {
6051 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN_FAILURE);
6052 ssh2_pkt_adduint32(ssh, c->remoteid);
6053 ssh2_pkt_adduint32(ssh, SSH2_OPEN_CONNECT_FAILED);
6054 ssh2_pkt_addstring(ssh, error);
6055 ssh2_pkt_addstring(ssh, "en"); /* language tag */
6056 ssh2_pkt_send(ssh);
6057 sfree(c);
6058 } else {
6059 c->localid = alloc_channel_id(ssh);
6060 c->closes = 0;
6061 c->v.v2.locwindow = OUR_V2_WINSIZE;
6062 c->v.v2.remwindow = winsize;
6063 c->v.v2.remmaxpkt = pktsize;
6064 bufchain_init(&c->v.v2.outbuffer);
6065 add234(ssh->channels, c);
6066 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
6067 ssh2_pkt_adduint32(ssh, c->remoteid);
6068 ssh2_pkt_adduint32(ssh, c->localid);
6069 ssh2_pkt_adduint32(ssh, c->v.v2.locwindow);
6070 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
6071 ssh2_pkt_send(ssh);
6072 }
6073 } else {
6074 bombout(("Strange packet received: type %d", ssh->pktin.type));
6075 crStopV;
6076 }
6077 } else {
6078 /*
6079 * We have spare data. Add it to the channel buffer.
6080 */
6081 ssh2_add_channel_data(ssh->mainchan, (char *)in, inlen);
6082 s->try_send = TRUE;
6083 }
6084 if (s->try_send) {
6085 int i;
6086 struct ssh_channel *c;
6087 /*
6088 * Try to send data on all channels if we can.
6089 */
6090 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
6091 int bufsize;
6092 if (c->closes)
6093 continue; /* don't send on closing channels */
6094 bufsize = ssh2_try_send(c);
6095 if (bufsize == 0) {
6096 switch (c->type) {
6097 case CHAN_MAINSESSION:
6098 /* stdin need not receive an unthrottle
6099 * notification since it will be polled */
6100 break;
6101 case CHAN_X11:
6102 x11_unthrottle(c->u.x11.s);
6103 break;
6104 case CHAN_AGENT:
6105 /* agent sockets are request/response and need no
6106 * buffer management */
6107 break;
6108 case CHAN_SOCKDATA:
6109 pfd_unthrottle(c->u.pfd.s);
6110 break;
6111 }
6112 }
6113 }
6114 }
6115 }
6116
6117 crFinishV;
6118 }
6119
6120 /*
6121 * Handle the top-level SSH2 protocol.
6122 */
6123 static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
6124 {
6125 if (do_ssh2_transport(ssh, in, inlen, ispkt) == 0)
6126 return;
6127 do_ssh2_authconn(ssh, in, inlen, ispkt);
6128 }
6129
6130 /*
6131 * Called to set up the connection.
6132 *
6133 * Returns an error message, or NULL on success.
6134 */
6135 static const char *ssh_init(void *frontend_handle, void **backend_handle,
6136 Config *cfg,
6137 char *host, int port, char **realhost, int nodelay)
6138 {
6139 const char *p;
6140 Ssh ssh;
6141
6142 ssh = snew(struct ssh_tag);
6143 ssh->cfg = *cfg; /* STRUCTURE COPY */
6144 ssh->version = 0; /* when not ready yet */
6145 ssh->s = NULL;
6146 ssh->cipher = NULL;
6147 ssh->v1_cipher_ctx = NULL;
6148 ssh->crcda_ctx = NULL;
6149 ssh->cscipher = NULL;
6150 ssh->cs_cipher_ctx = NULL;
6151 ssh->sccipher = NULL;
6152 ssh->sc_cipher_ctx = NULL;
6153 ssh->csmac = NULL;
6154 ssh->cs_mac_ctx = NULL;
6155 ssh->scmac = NULL;
6156 ssh->sc_mac_ctx = NULL;
6157 ssh->cscomp = NULL;
6158 ssh->cs_comp_ctx = NULL;
6159 ssh->sccomp = NULL;
6160 ssh->sc_comp_ctx = NULL;
6161 ssh->kex = NULL;
6162 ssh->kex_ctx = NULL;
6163 ssh->hostkey = NULL;
6164 ssh->exitcode = -1;
6165 ssh->state = SSH_STATE_PREPACKET;
6166 ssh->size_needed = FALSE;
6167 ssh->eof_needed = FALSE;
6168 ssh->ldisc = NULL;
6169 ssh->logctx = NULL;
6170 {
6171 static const struct Packet empty = { 0, 0, NULL, NULL, 0 };
6172 ssh->pktin = ssh->pktout = empty;
6173 }
6174 ssh->deferred_send_data = NULL;
6175 ssh->deferred_len = 0;
6176 ssh->deferred_size = 0;
6177 ssh->fallback_cmd = 0;
6178 ssh->pkt_ctx = 0;
6179 ssh->x11auth = NULL;
6180 ssh->v1_compressing = FALSE;
6181 ssh->v2_outgoing_sequence = 0;
6182 ssh->ssh1_rdpkt_crstate = 0;
6183 ssh->ssh2_rdpkt_crstate = 0;
6184 ssh->do_ssh_init_crstate = 0;
6185 ssh->ssh_gotdata_crstate = 0;
6186 ssh->ssh1_protocol_crstate = 0;
6187 ssh->do_ssh1_login_crstate = 0;
6188 ssh->do_ssh2_transport_crstate = 0;
6189 ssh->do_ssh2_authconn_crstate = 0;
6190 ssh->do_ssh_init_state = NULL;
6191 ssh->do_ssh1_login_state = NULL;
6192 ssh->do_ssh2_transport_state = NULL;
6193 ssh->do_ssh2_authconn_state = NULL;
6194 ssh->mainchan = NULL;
6195 ssh->throttled_all = 0;
6196 ssh->v1_stdout_throttling = 0;
6197
6198 *backend_handle = ssh;
6199
6200 #ifdef MSCRYPTOAPI
6201 if (crypto_startup() == 0)
6202 return "Microsoft high encryption pack not installed!";
6203 #endif
6204
6205 ssh->frontend = frontend_handle;
6206 ssh->term_width = ssh->cfg.width;
6207 ssh->term_height = ssh->cfg.height;
6208
6209 ssh->channels = NULL;
6210 ssh->rportfwds = NULL;
6211
6212 ssh->send_ok = 0;
6213 ssh->editing = 0;
6214 ssh->echoing = 0;
6215 ssh->v1_throttle_count = 0;
6216 ssh->overall_bufsize = 0;
6217 ssh->fallback_cmd = 0;
6218
6219 ssh->protocol = NULL;
6220
6221 p = connect_to_host(ssh, host, port, realhost, nodelay);
6222 if (p != NULL)
6223 return p;
6224
6225 return NULL;
6226 }
6227
6228 static void ssh_free(void *handle)
6229 {
6230 Ssh ssh = (Ssh) handle;
6231 struct ssh_channel *c;
6232 struct ssh_rportfwd *pf;
6233
6234 if (ssh->v1_cipher_ctx)
6235 ssh->cipher->free_context(ssh->v1_cipher_ctx);
6236 if (ssh->cs_cipher_ctx)
6237 ssh->cscipher->free_context(ssh->cs_cipher_ctx);
6238 if (ssh->sc_cipher_ctx)
6239 ssh->sccipher->free_context(ssh->sc_cipher_ctx);
6240 if (ssh->cs_mac_ctx)
6241 ssh->csmac->free_context(ssh->cs_mac_ctx);
6242 if (ssh->sc_mac_ctx)
6243 ssh->scmac->free_context(ssh->sc_mac_ctx);
6244 if (ssh->cs_comp_ctx)
6245 ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
6246 if (ssh->sc_comp_ctx)
6247 ssh->sccomp->compress_cleanup(ssh->sc_comp_ctx);
6248 if (ssh->kex_ctx)
6249 dh_cleanup(ssh->kex_ctx);
6250 sfree(ssh->savedhost);
6251
6252 if (ssh->channels) {
6253 while ((c = delpos234(ssh->channels, 0)) != NULL) {
6254 switch (c->type) {
6255 case CHAN_X11:
6256 if (c->u.x11.s != NULL)
6257 x11_close(c->u.x11.s);
6258 break;
6259 case CHAN_SOCKDATA:
6260 if (c->u.pfd.s != NULL)
6261 pfd_close(c->u.pfd.s);
6262 break;
6263 }
6264 sfree(c);
6265 }
6266 freetree234(ssh->channels);
6267 }
6268
6269 if (ssh->rportfwds) {
6270 while ((pf = delpos234(ssh->rportfwds, 0)) != NULL)
6271 sfree(pf);
6272 freetree234(ssh->rportfwds);
6273 }
6274 sfree(ssh->deferred_send_data);
6275 if (ssh->x11auth)
6276 x11_free_auth(ssh->x11auth);
6277 sfree(ssh->do_ssh_init_state);
6278 sfree(ssh->do_ssh1_login_state);
6279 sfree(ssh->do_ssh2_transport_state);
6280 sfree(ssh->do_ssh2_authconn_state);
6281
6282 if (ssh->s)
6283 ssh_do_close(ssh);
6284 sfree(ssh);
6285 }
6286
6287 /*
6288 * Reconfigure the SSH backend.
6289 *
6290 * Currently, this function does nothing very useful. In future,
6291 * however, we could do some handy things with it. For example, we
6292 * could make the port forwarding configurer active in the Change
6293 * Settings box, and this routine could close down existing
6294 * forwardings and open up new ones in response to changes.
6295 */
6296 static void ssh_reconfig(void *handle, Config *cfg)
6297 {
6298 Ssh ssh = (Ssh) handle;
6299 ssh->cfg = *cfg; /* STRUCTURE COPY */
6300 }
6301
6302 /*
6303 * Called to send data down the Telnet connection.
6304 */
6305 static int ssh_send(void *handle, char *buf, int len)
6306 {
6307 Ssh ssh = (Ssh) handle;
6308
6309 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
6310 return 0;
6311
6312 ssh->protocol(ssh, (unsigned char *)buf, len, 0);
6313
6314 return ssh_sendbuffer(ssh);
6315 }
6316
6317 /*
6318 * Called to query the current amount of buffered stdin data.
6319 */
6320 static int ssh_sendbuffer(void *handle)
6321 {
6322 Ssh ssh = (Ssh) handle;
6323 int override_value;
6324
6325 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
6326 return 0;
6327
6328 /*
6329 * If the SSH socket itself has backed up, add the total backup
6330 * size on that to any individual buffer on the stdin channel.
6331 */
6332 override_value = 0;
6333 if (ssh->throttled_all)
6334 override_value = ssh->overall_bufsize;
6335
6336 if (ssh->version == 1) {
6337 return override_value;
6338 } else if (ssh->version == 2) {
6339 if (!ssh->mainchan || ssh->mainchan->closes > 0)
6340 return override_value;
6341 else
6342 return (override_value +
6343 bufchain_size(&ssh->mainchan->v.v2.outbuffer));
6344 }
6345
6346 return 0;
6347 }
6348
6349 /*
6350 * Called to set the size of the window from SSH's POV.
6351 */
6352 static void ssh_size(void *handle, int width, int height)
6353 {
6354 Ssh ssh = (Ssh) handle;
6355
6356 ssh->term_width = width;
6357 ssh->term_height = height;
6358
6359 switch (ssh->state) {
6360 case SSH_STATE_BEFORE_SIZE:
6361 case SSH_STATE_PREPACKET:
6362 case SSH_STATE_CLOSED:
6363 break; /* do nothing */
6364 case SSH_STATE_INTERMED:
6365 ssh->size_needed = TRUE; /* buffer for later */
6366 break;
6367 case SSH_STATE_SESSION:
6368 if (!ssh->cfg.nopty) {
6369 if (ssh->version == 1) {
6370 send_packet(ssh, SSH1_CMSG_WINDOW_SIZE,
6371 PKT_INT, ssh->term_height,
6372 PKT_INT, ssh->term_width,
6373 PKT_INT, 0, PKT_INT, 0, PKT_END);
6374 } else {
6375 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
6376 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
6377 ssh2_pkt_addstring(ssh, "window-change");
6378 ssh2_pkt_addbool(ssh, 0);
6379 ssh2_pkt_adduint32(ssh, ssh->term_width);
6380 ssh2_pkt_adduint32(ssh, ssh->term_height);
6381 ssh2_pkt_adduint32(ssh, 0);
6382 ssh2_pkt_adduint32(ssh, 0);
6383 ssh2_pkt_send(ssh);
6384 }
6385 }
6386 break;
6387 }
6388 }
6389
6390 /*
6391 * Return a list of the special codes that make sense in this
6392 * protocol.
6393 */
6394 static const struct telnet_special *ssh_get_specials(void *handle)
6395 {
6396 Ssh ssh = (Ssh) handle;
6397
6398 if (ssh->version == 1) {
6399 static const struct telnet_special ssh1_specials[] = {
6400 {"IGNORE message", TS_NOP},
6401 {NULL, 0}
6402 };
6403 return ssh1_specials;
6404 } else if (ssh->version == 2) {
6405 static const struct telnet_special ssh2_specials[] = {
6406 {"Break", TS_BRK},
6407 {"IGNORE message", TS_NOP},
6408 {NULL, 0}
6409 };
6410 return ssh2_specials;
6411 } else
6412 return NULL;
6413 }
6414
6415 /*
6416 * Send Telnet special codes. TS_EOF is useful for `plink', so you
6417 * can send an EOF and collect resulting output (e.g. `plink
6418 * hostname sort').
6419 */
6420 static void ssh_special(void *handle, Telnet_Special code)
6421 {
6422 Ssh ssh = (Ssh) handle;
6423
6424 if (code == TS_EOF) {
6425 if (ssh->state != SSH_STATE_SESSION) {
6426 /*
6427 * Buffer the EOF in case we are pre-SESSION, so we can
6428 * send it as soon as we reach SESSION.
6429 */
6430 if (code == TS_EOF)
6431 ssh->eof_needed = TRUE;
6432 return;
6433 }
6434 if (ssh->version == 1) {
6435 send_packet(ssh, SSH1_CMSG_EOF, PKT_END);
6436 } else {
6437 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_EOF);
6438 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
6439 ssh2_pkt_send(ssh);
6440 }
6441 logevent("Sent EOF message");
6442 } else if (code == TS_PING || code == TS_NOP) {
6443 if (ssh->state == SSH_STATE_CLOSED
6444 || ssh->state == SSH_STATE_PREPACKET) return;
6445 if (ssh->version == 1) {
6446 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE))
6447 send_packet(ssh, SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
6448 } else {
6449 ssh2_pkt_init(ssh, SSH2_MSG_IGNORE);
6450 ssh2_pkt_addstring_start(ssh);
6451 ssh2_pkt_send(ssh);
6452 }
6453 } else if (code == TS_BRK) {
6454 if (ssh->state == SSH_STATE_CLOSED
6455 || ssh->state == SSH_STATE_PREPACKET) return;
6456 if (ssh->version == 1) {
6457 logevent("Unable to send BREAK signal in SSH1");
6458 } else {
6459 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
6460 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
6461 ssh2_pkt_addstring(ssh, "break");
6462 ssh2_pkt_addbool(ssh, 0);
6463 ssh2_pkt_adduint32(ssh, 0); /* default break length */
6464 ssh2_pkt_send(ssh);
6465 }
6466 } else {
6467 /* do nothing */
6468 }
6469 }
6470
6471 void *new_sock_channel(void *handle, Socket s)
6472 {
6473 Ssh ssh = (Ssh) handle;
6474 struct ssh_channel *c;
6475 c = snew(struct ssh_channel);
6476 c->ssh = ssh;
6477
6478 if (c) {
6479 c->remoteid = -1; /* to be set when open confirmed */
6480 c->localid = alloc_channel_id(ssh);
6481 c->closes = 0;
6482 c->type = CHAN_SOCKDATA_DORMANT;/* identify channel type */
6483 c->u.pfd.s = s;
6484 bufchain_init(&c->v.v2.outbuffer);
6485 add234(ssh->channels, c);
6486 }
6487 return c;
6488 }
6489
6490 /*
6491 * This is called when stdout/stderr (the entity to which
6492 * from_backend sends data) manages to clear some backlog.
6493 */
6494 static void ssh_unthrottle(void *handle, int bufsize)
6495 {
6496 Ssh ssh = (Ssh) handle;
6497 if (ssh->version == 1) {
6498 if (ssh->v1_stdout_throttling && bufsize < SSH1_BUFFER_LIMIT) {
6499 ssh->v1_stdout_throttling = 0;
6500 ssh1_throttle(ssh, -1);
6501 }
6502 } else {
6503 if (ssh->mainchan && ssh->mainchan->closes == 0)
6504 ssh2_set_window(ssh->mainchan, OUR_V2_WINSIZE - bufsize);
6505 }
6506 }
6507
6508 void ssh_send_port_open(void *channel, char *hostname, int port, char *org)
6509 {
6510 struct ssh_channel *c = (struct ssh_channel *)channel;
6511 Ssh ssh = c->ssh;
6512
6513 logeventf(ssh, "Opening forwarded connection to %s:%d", hostname, port);
6514
6515 if (ssh->version == 1) {
6516 send_packet(ssh, SSH1_MSG_PORT_OPEN,
6517 PKT_INT, c->localid,
6518 PKT_STR, hostname,
6519 PKT_INT, port,
6520 //PKT_STR, <org:orgport>,
6521 PKT_END);
6522 } else {
6523 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN);
6524 ssh2_pkt_addstring(ssh, "direct-tcpip");
6525 ssh2_pkt_adduint32(ssh, c->localid);
6526 c->v.v2.locwindow = OUR_V2_WINSIZE;
6527 ssh2_pkt_adduint32(ssh, c->v.v2.locwindow);/* our window size */
6528 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
6529 ssh2_pkt_addstring(ssh, hostname);
6530 ssh2_pkt_adduint32(ssh, port);
6531 /*
6532 * We make up values for the originator data; partly it's
6533 * too much hassle to keep track, and partly I'm not
6534 * convinced the server should be told details like that
6535 * about my local network configuration.
6536 */
6537 ssh2_pkt_addstring(ssh, "client-side-connection");
6538 ssh2_pkt_adduint32(ssh, 0);
6539 ssh2_pkt_send(ssh);
6540 }
6541 }
6542
6543
6544 static Socket ssh_socket(void *handle)
6545 {
6546 Ssh ssh = (Ssh) handle;
6547 return ssh->s;
6548 }
6549
6550 static int ssh_sendok(void *handle)
6551 {
6552 Ssh ssh = (Ssh) handle;
6553 return ssh->send_ok;
6554 }
6555
6556 static int ssh_ldisc(void *handle, int option)
6557 {
6558 Ssh ssh = (Ssh) handle;
6559 if (option == LD_ECHO)
6560 return ssh->echoing;
6561 if (option == LD_EDIT)
6562 return ssh->editing;
6563 return FALSE;
6564 }
6565
6566 static void ssh_provide_ldisc(void *handle, void *ldisc)
6567 {
6568 Ssh ssh = (Ssh) handle;
6569 ssh->ldisc = ldisc;
6570 }
6571
6572 static void ssh_provide_logctx(void *handle, void *logctx)
6573 {
6574 Ssh ssh = (Ssh) handle;
6575 ssh->logctx = logctx;
6576 }
6577
6578 static int ssh_return_exitcode(void *handle)
6579 {
6580 Ssh ssh = (Ssh) handle;
6581 if (ssh->s != NULL)
6582 return -1;
6583 else
6584 return (ssh->exitcode >= 0 ? ssh->exitcode : 0);
6585 }
6586
6587 /*
6588 * Gross hack: pscp will try to start SFTP but fall back to scp1 if
6589 * that fails. This variable is the means by which scp.c can reach
6590 * into the SSH code and find out which one it got.
6591 */
6592 extern int ssh_fallback_cmd(void *handle)
6593 {
6594 Ssh ssh = (Ssh) handle;
6595 return ssh->fallback_cmd;
6596 }
6597
6598 Backend ssh_backend = {
6599 ssh_init,
6600 ssh_free,
6601 ssh_reconfig,
6602 ssh_send,
6603 ssh_sendbuffer,
6604 ssh_size,
6605 ssh_special,
6606 ssh_get_specials,
6607 ssh_socket,
6608 ssh_return_exitcode,
6609 ssh_sendok,
6610 ssh_ldisc,
6611 ssh_provide_ldisc,
6612 ssh_provide_logctx,
6613 ssh_unthrottle,
6614 22
6615 };
Local modifications for Simon Tatham's `PuTTY' SSH client and terminal emulator