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