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81ca0c87c32d4bfd9a20b1182931cf1043142a3d
[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, 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(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(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("2.1.0*", imp) || wc_match("2.0.*", imp) ||
1817 wc_match("2.2.0*", imp) || wc_match("2.3.0*", imp) ||
1818 wc_match("2.1 *", imp)))) {
1819 /*
1820 * These versions have the HMAC bug.
1821 */
1822 ssh->remote_bugs |= BUG_SSH2_HMAC;
1823 logevent("We believe remote version has SSH2 HMAC bug");
1824 }
1825
1826 if (ssh->cfg.sshbug_derivekey2 == FORCE_ON ||
1827 (ssh->cfg.sshbug_derivekey2 == AUTO &&
1828 (wc_match("2.0.0*", imp) || wc_match("2.0.10*", imp) ))) {
1829 /*
1830 * These versions have the key-derivation bug (failing to
1831 * include the literal shared secret in the hashes that
1832 * generate the keys).
1833 */
1834 ssh->remote_bugs |= BUG_SSH2_DERIVEKEY;
1835 logevent("We believe remote version has SSH2 key-derivation bug");
1836 }
1837
1838 if (ssh->cfg.sshbug_rsapad2 == FORCE_ON ||
1839 (ssh->cfg.sshbug_rsapad2 == AUTO &&
1840 (wc_match("OpenSSH_2.[5-9]*", imp) ||
1841 wc_match("OpenSSH_3.[0-2]*", imp)))) {
1842 /*
1843 * These versions have the SSH2 RSA padding bug.
1844 */
1845 ssh->remote_bugs |= BUG_SSH2_RSA_PADDING;
1846 logevent("We believe remote version has SSH2 RSA padding bug");
1847 }
1848
1849 if (ssh->cfg.sshbug_pksessid2 == FORCE_ON ||
1850 (ssh->cfg.sshbug_pksessid2 == AUTO &&
1851 wc_match("OpenSSH_2.[0-2]*", imp))) {
1852 /*
1853 * These versions have the SSH2 session-ID bug in
1854 * public-key authentication.
1855 */
1856 ssh->remote_bugs |= BUG_SSH2_PK_SESSIONID;
1857 logevent("We believe remote version has SSH2 public-key-session-ID bug");
1858 }
1859
1860 if (ssh->cfg.sshbug_dhgex2 == FORCE_ON) {
1861 /*
1862 * User specified the SSH2 DH GEX bug.
1863 */
1864 ssh->remote_bugs |= BUG_SSH2_DH_GEX;
1865 logevent("We believe remote version has SSH2 DH group exchange bug");
1866 }
1867 }
1868
1869 static int do_ssh_init(Ssh ssh, unsigned char c)
1870 {
1871 struct do_ssh_init_state {
1872 int vslen;
1873 char version[10];
1874 char *vstring;
1875 int vstrsize;
1876 int i;
1877 int proto1, proto2;
1878 };
1879 crState(do_ssh_init_state);
1880
1881 crBegin(ssh->do_ssh_init_crstate);
1882
1883 /* Search for the string "SSH-" in the input. */
1884 s->i = 0;
1885 while (1) {
1886 static const int transS[] = { 1, 2, 2, 1 };
1887 static const int transH[] = { 0, 0, 3, 0 };
1888 static const int transminus[] = { 0, 0, 0, -1 };
1889 if (c == 'S')
1890 s->i = transS[s->i];
1891 else if (c == 'H')
1892 s->i = transH[s->i];
1893 else if (c == '-')
1894 s->i = transminus[s->i];
1895 else
1896 s->i = 0;
1897 if (s->i < 0)
1898 break;
1899 crReturn(1); /* get another character */
1900 }
1901
1902 s->vstrsize = 16;
1903 s->vstring = snewn(s->vstrsize, char);
1904 strcpy(s->vstring, "SSH-");
1905 s->vslen = 4;
1906 s->i = 0;
1907 while (1) {
1908 crReturn(1); /* get another char */
1909 if (s->vslen >= s->vstrsize - 1) {
1910 s->vstrsize += 16;
1911 s->vstring = sresize(s->vstring, s->vstrsize, char);
1912 }
1913 s->vstring[s->vslen++] = c;
1914 if (s->i >= 0) {
1915 if (c == '-') {
1916 s->version[s->i] = '\0';
1917 s->i = -1;
1918 } else if (s->i < sizeof(s->version) - 1)
1919 s->version[s->i++] = c;
1920 } else if (c == '\012')
1921 break;
1922 }
1923
1924 ssh->agentfwd_enabled = FALSE;
1925 ssh->rdpkt2_state.incoming_sequence = 0;
1926
1927 s->vstring[s->vslen] = 0;
1928 s->vstring[strcspn(s->vstring, "\r\n")] = '\0';/* remove EOL chars */
1929 {
1930 char *vlog;
1931 vlog = snewn(20 + s->vslen, char);
1932 sprintf(vlog, "Server version: %s", s->vstring);
1933 logevent(vlog);
1934 sfree(vlog);
1935 }
1936 ssh_detect_bugs(ssh, s->vstring);
1937
1938 /*
1939 * Decide which SSH protocol version to support.
1940 */
1941
1942 /* Anything strictly below "2.0" means protocol 1 is supported. */
1943 s->proto1 = ssh_versioncmp(s->version, "2.0") < 0;
1944 /* Anything greater or equal to "1.99" means protocol 2 is supported. */
1945 s->proto2 = ssh_versioncmp(s->version, "1.99") >= 0;
1946
1947 if (ssh->cfg.sshprot == 0 && !s->proto1) {
1948 bombout(("SSH protocol version 1 required by user but not provided by server"));
1949 crStop(0);
1950 }
1951 if (ssh->cfg.sshprot == 3 && !s->proto2) {
1952 bombout(("SSH protocol version 2 required by user but not provided by server"));
1953 crStop(0);
1954 }
1955
1956 if (s->proto2 && (ssh->cfg.sshprot >= 2 || !s->proto1)) {
1957 /*
1958 * Use v2 protocol.
1959 */
1960 char verstring[80], vlog[100];
1961 sprintf(verstring, "SSH-2.0-%s", sshver);
1962 SHA_Init(&ssh->exhashbase);
1963 /*
1964 * Hash our version string and their version string.
1965 */
1966 sha_string(&ssh->exhashbase, verstring, strlen(verstring));
1967 sha_string(&ssh->exhashbase, s->vstring, strcspn(s->vstring, "\r\n"));
1968 sprintf(vlog, "We claim version: %s", verstring);
1969 logevent(vlog);
1970 strcat(verstring, "\012");
1971 logevent("Using SSH protocol version 2");
1972 sk_write(ssh->s, verstring, strlen(verstring));
1973 ssh->protocol = ssh2_protocol;
1974 ssh->version = 2;
1975 ssh->s_rdpkt = ssh2_rdpkt;
1976 } else {
1977 /*
1978 * Use v1 protocol.
1979 */
1980 char verstring[80], vlog[100];
1981 sprintf(verstring, "SSH-%s-%s",
1982 (ssh_versioncmp(s->version, "1.5") <= 0 ? s->version : "1.5"),
1983 sshver);
1984 sprintf(vlog, "We claim version: %s", verstring);
1985 logevent(vlog);
1986 strcat(verstring, "\012");
1987
1988 logevent("Using SSH protocol version 1");
1989 sk_write(ssh->s, verstring, strlen(verstring));
1990 ssh->protocol = ssh1_protocol;
1991 ssh->version = 1;
1992 ssh->s_rdpkt = ssh1_rdpkt;
1993 }
1994 update_specials_menu(ssh->frontend);
1995 ssh->state = SSH_STATE_BEFORE_SIZE;
1996
1997 sfree(s->vstring);
1998
1999 crFinish(0);
2000 }
2001
2002 static void ssh_gotdata(Ssh ssh, unsigned char *data, int datalen)
2003 {
2004 crBegin(ssh->ssh_gotdata_crstate);
2005
2006 /*
2007 * To begin with, feed the characters one by one to the
2008 * protocol initialisation / selection function do_ssh_init().
2009 * When that returns 0, we're done with the initial greeting
2010 * exchange and can move on to packet discipline.
2011 */
2012 while (1) {
2013 int ret; /* need not be kept across crReturn */
2014 if (datalen == 0)
2015 crReturnV; /* more data please */
2016 ret = do_ssh_init(ssh, *data);
2017 data++;
2018 datalen--;
2019 if (ret == 0)
2020 break;
2021 }
2022
2023 /*
2024 * We emerge from that loop when the initial negotiation is
2025 * over and we have selected an s_rdpkt function. Now pass
2026 * everything to s_rdpkt, and then pass the resulting packets
2027 * to the proper protocol handler.
2028 */
2029 if (datalen == 0)
2030 crReturnV;
2031 while (1) {
2032 while (datalen > 0) {
2033 if (ssh->s_rdpkt(ssh, &data, &datalen) == 0) {
2034 if (ssh->state == SSH_STATE_CLOSED) {
2035 return;
2036 }
2037 ssh->protocol(ssh, NULL, 0, 1);
2038 if (ssh->state == SSH_STATE_CLOSED) {
2039 return;
2040 }
2041 }
2042 }
2043 crReturnV;
2044 }
2045 crFinishV;
2046 }
2047
2048 static void ssh_do_close(Ssh ssh)
2049 {
2050 int i;
2051 struct ssh_channel *c;
2052
2053 ssh->state = SSH_STATE_CLOSED;
2054 if (ssh->s) {
2055 sk_close(ssh->s);
2056 ssh->s = NULL;
2057 }
2058 /*
2059 * Now we must shut down any port and X forwardings going
2060 * through this connection.
2061 */
2062 if (ssh->channels) {
2063 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
2064 switch (c->type) {
2065 case CHAN_X11:
2066 x11_close(c->u.x11.s);
2067 break;
2068 case CHAN_SOCKDATA:
2069 pfd_close(c->u.pfd.s);
2070 break;
2071 }
2072 del234(ssh->channels, c);
2073 if (ssh->version == 2)
2074 bufchain_clear(&c->v.v2.outbuffer);
2075 sfree(c);
2076 }
2077 }
2078 }
2079
2080 static int ssh_closing(Plug plug, char *error_msg, int error_code,
2081 int calling_back)
2082 {
2083 Ssh ssh = (Ssh) plug;
2084 ssh_do_close(ssh);
2085 if (error_msg) {
2086 /* A socket error has occurred. */
2087 logevent(error_msg);
2088 connection_fatal(ssh->frontend, error_msg);
2089 } else {
2090 /* Otherwise, the remote side closed the connection normally. */
2091 }
2092 return 0;
2093 }
2094
2095 static int ssh_receive(Plug plug, int urgent, char *data, int len)
2096 {
2097 Ssh ssh = (Ssh) plug;
2098 ssh_gotdata(ssh, (unsigned char *)data, len);
2099 if (ssh->state == SSH_STATE_CLOSED) {
2100 ssh_do_close(ssh);
2101 return 0;
2102 }
2103 return 1;
2104 }
2105
2106 static void ssh_sent(Plug plug, int bufsize)
2107 {
2108 Ssh ssh = (Ssh) plug;
2109 /*
2110 * If the send backlog on the SSH socket itself clears, we
2111 * should unthrottle the whole world if it was throttled.
2112 */
2113 if (bufsize < SSH_MAX_BACKLOG)
2114 ssh_throttle_all(ssh, 0, bufsize);
2115 }
2116
2117 /*
2118 * Connect to specified host and port.
2119 * Returns an error message, or NULL on success.
2120 * Also places the canonical host name into `realhost'. It must be
2121 * freed by the caller.
2122 */
2123 static char *connect_to_host(Ssh ssh, char *host, int port,
2124 char **realhost, int nodelay)
2125 {
2126 static const struct plug_function_table fn_table = {
2127 ssh_closing,
2128 ssh_receive,
2129 ssh_sent,
2130 NULL
2131 };
2132
2133 SockAddr addr;
2134 char *err;
2135
2136 ssh->savedhost = snewn(1 + strlen(host), char);
2137 if (!ssh->savedhost)
2138 fatalbox("Out of memory");
2139 strcpy(ssh->savedhost, host);
2140
2141 if (port < 0)
2142 port = 22; /* default ssh port */
2143 ssh->savedport = port;
2144
2145 /*
2146 * Try to find host.
2147 */
2148 logeventf(ssh, "Looking up host \"%s\"", host);
2149 addr = name_lookup(host, port, realhost, &ssh->cfg);
2150 if ((err = sk_addr_error(addr)) != NULL)
2151 return err;
2152
2153 /*
2154 * Open socket.
2155 */
2156 {
2157 char addrbuf[100];
2158 sk_getaddr(addr, addrbuf, 100);
2159 logeventf(ssh, "Connecting to %s port %d", addrbuf, port);
2160 }
2161 ssh->fn = &fn_table;
2162 ssh->s = new_connection(addr, *realhost, port,
2163 0, 1, nodelay, (Plug) ssh, &ssh->cfg);
2164 if ((err = sk_socket_error(ssh->s)) != NULL) {
2165 ssh->s = NULL;
2166 return err;
2167 }
2168
2169 return NULL;
2170 }
2171
2172 /*
2173 * Throttle or unthrottle the SSH connection.
2174 */
2175 static void ssh1_throttle(Ssh ssh, int adjust)
2176 {
2177 int old_count = ssh->v1_throttle_count;
2178 ssh->v1_throttle_count += adjust;
2179 assert(ssh->v1_throttle_count >= 0);
2180 if (ssh->v1_throttle_count && !old_count) {
2181 sk_set_frozen(ssh->s, 1);
2182 } else if (!ssh->v1_throttle_count && old_count) {
2183 sk_set_frozen(ssh->s, 0);
2184 }
2185 }
2186
2187 /*
2188 * Throttle or unthrottle _all_ local data streams (for when sends
2189 * on the SSH connection itself back up).
2190 */
2191 static void ssh_throttle_all(Ssh ssh, int enable, int bufsize)
2192 {
2193 int i;
2194 struct ssh_channel *c;
2195
2196 if (enable == ssh->throttled_all)
2197 return;
2198 ssh->throttled_all = enable;
2199 ssh->overall_bufsize = bufsize;
2200 if (!ssh->channels)
2201 return;
2202 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
2203 switch (c->type) {
2204 case CHAN_MAINSESSION:
2205 /*
2206 * This is treated separately, outside the switch.
2207 */
2208 break;
2209 case CHAN_X11:
2210 x11_override_throttle(c->u.x11.s, enable);
2211 break;
2212 case CHAN_AGENT:
2213 /* Agent channels require no buffer management. */
2214 break;
2215 case CHAN_SOCKDATA:
2216 pfd_override_throttle(c->u.pfd.s, enable);
2217 break;
2218 }
2219 }
2220 }
2221
2222 /*
2223 * Username and password input, abstracted off into routines
2224 * reusable in several places - even between SSH1 and SSH2.
2225 */
2226
2227 /* Set up a username or password input loop on a given buffer. */
2228 static void setup_userpass_input(Ssh ssh, char *buffer, int buflen, int echo)
2229 {
2230 ssh->userpass_input_buffer = buffer;
2231 ssh->userpass_input_buflen = buflen;
2232 ssh->userpass_input_bufpos = 0;
2233 ssh->userpass_input_echo = echo;
2234 }
2235
2236 /*
2237 * Process some terminal data in the course of username/password
2238 * input. Returns >0 for success (line of input returned in
2239 * buffer), <0 for failure (user hit ^C/^D, bomb out and exit), 0
2240 * for inconclusive (keep waiting for more input please).
2241 */
2242 static int process_userpass_input(Ssh ssh, unsigned char *in, int inlen)
2243 {
2244 char c;
2245
2246 while (inlen--) {
2247 switch (c = *in++) {
2248 case 10:
2249 case 13:
2250 ssh->userpass_input_buffer[ssh->userpass_input_bufpos] = 0;
2251 ssh->userpass_input_buffer[ssh->userpass_input_buflen-1] = 0;
2252 return +1;
2253 break;
2254 case 8:
2255 case 127:
2256 if (ssh->userpass_input_bufpos > 0) {
2257 if (ssh->userpass_input_echo)
2258 c_write_str(ssh, "\b \b");
2259 ssh->userpass_input_bufpos--;
2260 }
2261 break;
2262 case 21:
2263 case 27:
2264 while (ssh->userpass_input_bufpos > 0) {
2265 if (ssh->userpass_input_echo)
2266 c_write_str(ssh, "\b \b");
2267 ssh->userpass_input_bufpos--;
2268 }
2269 break;
2270 case 3:
2271 case 4:
2272 return -1;
2273 break;
2274 default:
2275 /*
2276 * This simplistic check for printability is disabled
2277 * when we're doing password input, because some people
2278 * have control characters in their passwords.o
2279 */
2280 if ((!ssh->userpass_input_echo ||
2281 (c >= ' ' && c <= '~') ||
2282 ((unsigned char) c >= 160))
2283 && ssh->userpass_input_bufpos < ssh->userpass_input_buflen-1) {
2284 ssh->userpass_input_buffer[ssh->userpass_input_bufpos++] = c;
2285 if (ssh->userpass_input_echo)
2286 c_write(ssh, &c, 1);
2287 }
2288 break;
2289 }
2290 }
2291 return 0;
2292 }
2293
2294 void ssh_agent_callback(void *sshv, void *reply, int replylen)
2295 {
2296 Ssh ssh = (Ssh) sshv;
2297
2298 ssh->agent_response = reply;
2299 ssh->agent_response_len = replylen;
2300
2301 if (ssh->version == 1)
2302 do_ssh1_login(ssh, NULL, -1, 0);
2303 else
2304 do_ssh2_authconn(ssh, NULL, -1, 0);
2305 }
2306
2307 void ssh_agentf_callback(void *cv, void *reply, int replylen)
2308 {
2309 struct ssh_channel *c = (struct ssh_channel *)cv;
2310 Ssh ssh = c->ssh;
2311 void *sentreply = reply;
2312
2313 if (!sentreply) {
2314 /* Fake SSH_AGENT_FAILURE. */
2315 sentreply = "\0\0\0\1\5";
2316 replylen = 5;
2317 }
2318 if (ssh->version == 2) {
2319 ssh2_add_channel_data(c, sentreply, replylen);
2320 ssh2_try_send(c);
2321 } else {
2322 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
2323 PKT_INT, c->remoteid,
2324 PKT_INT, replylen,
2325 PKT_DATA, sentreply, replylen,
2326 PKT_END);
2327 }
2328 if (reply)
2329 sfree(reply);
2330 }
2331
2332 /*
2333 * Handle the key exchange and user authentication phases.
2334 */
2335 static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
2336 {
2337 int i, j;
2338 unsigned char cookie[8];
2339 struct RSAKey servkey, hostkey;
2340 struct MD5Context md5c;
2341 struct do_ssh1_login_state {
2342 int len;
2343 unsigned char *rsabuf, *keystr1, *keystr2;
2344 unsigned long supported_ciphers_mask, supported_auths_mask;
2345 int tried_publickey, tried_agent;
2346 int tis_auth_refused, ccard_auth_refused;
2347 unsigned char session_id[16];
2348 int cipher_type;
2349 char username[100];
2350 void *publickey_blob;
2351 int publickey_bloblen;
2352 char password[100];
2353 char prompt[200];
2354 int pos;
2355 char c;
2356 int pwpkt_type;
2357 unsigned char request[5], *response, *p;
2358 int responselen;
2359 int keyi, nkeys;
2360 int authed;
2361 struct RSAKey key;
2362 Bignum challenge;
2363 char *commentp;
2364 int commentlen;
2365 };
2366 crState(do_ssh1_login_state);
2367
2368 crBegin(ssh->do_ssh1_login_crstate);
2369
2370 if (!ispkt)
2371 crWaitUntil(ispkt);
2372
2373 if (ssh->pktin.type != SSH1_SMSG_PUBLIC_KEY) {
2374 bombout(("Public key packet not received"));
2375 crStop(0);
2376 }
2377
2378 logevent("Received public keys");
2379
2380 memcpy(cookie, ssh->pktin.body, 8);
2381
2382 i = makekey(ssh->pktin.body + 8, &servkey, &s->keystr1, 0);
2383 j = makekey(ssh->pktin.body + 8 + i, &hostkey, &s->keystr2, 0);
2384
2385 /*
2386 * Log the host key fingerprint.
2387 */
2388 {
2389 char logmsg[80];
2390 logevent("Host key fingerprint is:");
2391 strcpy(logmsg, " ");
2392 hostkey.comment = NULL;
2393 rsa_fingerprint(logmsg + strlen(logmsg),
2394 sizeof(logmsg) - strlen(logmsg), &hostkey);
2395 logevent(logmsg);
2396 }
2397
2398 ssh->v1_remote_protoflags = GET_32BIT(ssh->pktin.body + 8 + i + j);
2399 s->supported_ciphers_mask = GET_32BIT(ssh->pktin.body + 12 + i + j);
2400 s->supported_auths_mask = GET_32BIT(ssh->pktin.body + 16 + i + j);
2401
2402 ssh->v1_local_protoflags =
2403 ssh->v1_remote_protoflags & SSH1_PROTOFLAGS_SUPPORTED;
2404 ssh->v1_local_protoflags |= SSH1_PROTOFLAG_SCREEN_NUMBER;
2405
2406 MD5Init(&md5c);
2407 MD5Update(&md5c, s->keystr2, hostkey.bytes);
2408 MD5Update(&md5c, s->keystr1, servkey.bytes);
2409 MD5Update(&md5c, ssh->pktin.body, 8);
2410 MD5Final(s->session_id, &md5c);
2411
2412 for (i = 0; i < 32; i++)
2413 ssh->session_key[i] = random_byte();
2414
2415 s->len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes);
2416
2417 s->rsabuf = snewn(s->len, unsigned char);
2418 if (!s->rsabuf)
2419 fatalbox("Out of memory");
2420
2421 /*
2422 * Verify the host key.
2423 */
2424 {
2425 /*
2426 * First format the key into a string.
2427 */
2428 int len = rsastr_len(&hostkey);
2429 char fingerprint[100];
2430 char *keystr = snewn(len, char);
2431 if (!keystr)
2432 fatalbox("Out of memory");
2433 rsastr_fmt(keystr, &hostkey);
2434 rsa_fingerprint(fingerprint, sizeof(fingerprint), &hostkey);
2435 verify_ssh_host_key(ssh->frontend,
2436 ssh->savedhost, ssh->savedport, "rsa", keystr,
2437 fingerprint);
2438 sfree(keystr);
2439 }
2440
2441 for (i = 0; i < 32; i++) {
2442 s->rsabuf[i] = ssh->session_key[i];
2443 if (i < 16)
2444 s->rsabuf[i] ^= s->session_id[i];
2445 }
2446
2447 if (hostkey.bytes > servkey.bytes) {
2448 rsaencrypt(s->rsabuf, 32, &servkey);
2449 rsaencrypt(s->rsabuf, servkey.bytes, &hostkey);
2450 } else {
2451 rsaencrypt(s->rsabuf, 32, &hostkey);
2452 rsaencrypt(s->rsabuf, hostkey.bytes, &servkey);
2453 }
2454
2455 logevent("Encrypted session key");
2456
2457 {
2458 int cipher_chosen = 0, warn = 0;
2459 char *cipher_string = NULL;
2460 int i;
2461 for (i = 0; !cipher_chosen && i < CIPHER_MAX; i++) {
2462 int next_cipher = ssh->cfg.ssh_cipherlist[i];
2463 if (next_cipher == CIPHER_WARN) {
2464 /* If/when we choose a cipher, warn about it */
2465 warn = 1;
2466 } else if (next_cipher == CIPHER_AES) {
2467 /* XXX Probably don't need to mention this. */
2468 logevent("AES not supported in SSH1, skipping");
2469 } else {
2470 switch (next_cipher) {
2471 case CIPHER_3DES: s->cipher_type = SSH_CIPHER_3DES;
2472 cipher_string = "3DES"; break;
2473 case CIPHER_BLOWFISH: s->cipher_type = SSH_CIPHER_BLOWFISH;
2474 cipher_string = "Blowfish"; break;
2475 case CIPHER_DES: s->cipher_type = SSH_CIPHER_DES;
2476 cipher_string = "single-DES"; break;
2477 }
2478 if (s->supported_ciphers_mask & (1 << s->cipher_type))
2479 cipher_chosen = 1;
2480 }
2481 }
2482 if (!cipher_chosen) {
2483 if ((s->supported_ciphers_mask & (1 << SSH_CIPHER_3DES)) == 0)
2484 bombout(("Server violates SSH 1 protocol by not "
2485 "supporting 3DES encryption"));
2486 else
2487 /* shouldn't happen */
2488 bombout(("No supported ciphers found"));
2489 crStop(0);
2490 }
2491
2492 /* Warn about chosen cipher if necessary. */
2493 if (warn)
2494 askcipher(ssh->frontend, cipher_string, 0);
2495 }
2496
2497 switch (s->cipher_type) {
2498 case SSH_CIPHER_3DES:
2499 logevent("Using 3DES encryption");
2500 break;
2501 case SSH_CIPHER_DES:
2502 logevent("Using single-DES encryption");
2503 break;
2504 case SSH_CIPHER_BLOWFISH:
2505 logevent("Using Blowfish encryption");
2506 break;
2507 }
2508
2509 send_packet(ssh, SSH1_CMSG_SESSION_KEY,
2510 PKT_CHAR, s->cipher_type,
2511 PKT_DATA, cookie, 8,
2512 PKT_CHAR, (s->len * 8) >> 8, PKT_CHAR, (s->len * 8) & 0xFF,
2513 PKT_DATA, s->rsabuf, s->len,
2514 PKT_INT, ssh->v1_local_protoflags, PKT_END);
2515
2516 logevent("Trying to enable encryption...");
2517
2518 sfree(s->rsabuf);
2519
2520 ssh->cipher = (s->cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 :
2521 s->cipher_type == SSH_CIPHER_DES ? &ssh_des :
2522 &ssh_3des);
2523 ssh->v1_cipher_ctx = ssh->cipher->make_context();
2524 ssh->cipher->sesskey(ssh->v1_cipher_ctx, ssh->session_key);
2525 logeventf(ssh, "Initialised %s encryption", ssh->cipher->text_name);
2526
2527 ssh->crcda_ctx = crcda_make_context();
2528 logevent("Installing CRC compensation attack detector");
2529
2530 crWaitUntil(ispkt);
2531
2532 if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
2533 bombout(("Encryption not successfully enabled"));
2534 crStop(0);
2535 }
2536
2537 logevent("Successfully started encryption");
2538
2539 fflush(stdout);
2540 {
2541 if ((flags & FLAG_INTERACTIVE) && !*ssh->cfg.username) {
2542 if (ssh_get_line && !ssh_getline_pw_only) {
2543 if (!ssh_get_line("login as: ",
2544 s->username, sizeof(s->username), FALSE)) {
2545 /*
2546 * get_line failed to get a username.
2547 * Terminate.
2548 */
2549 logevent("No username provided. Abandoning session.");
2550 ssh_closing((Plug)ssh, NULL, 0, 0);
2551 crStop(1);
2552 }
2553 } else {
2554 int ret; /* need not be kept over crReturn */
2555 c_write_str(ssh, "login as: ");
2556 ssh->send_ok = 1;
2557
2558 setup_userpass_input(ssh, s->username, sizeof(s->username), 1);
2559 do {
2560 crWaitUntil(!ispkt);
2561 ret = process_userpass_input(ssh, in, inlen);
2562 } while (ret == 0);
2563 if (ret < 0)
2564 cleanup_exit(0);
2565 c_write_str(ssh, "\r\n");
2566 }
2567 } else {
2568 strncpy(s->username, ssh->cfg.username, sizeof(s->username));
2569 s->username[sizeof(s->username)-1] = '\0';
2570 }
2571
2572 send_packet(ssh, SSH1_CMSG_USER, PKT_STR, s->username, PKT_END);
2573 {
2574 char userlog[22 + sizeof(s->username)];
2575 sprintf(userlog, "Sent username \"%s\"", s->username);
2576 logevent(userlog);
2577 if (flags & FLAG_INTERACTIVE &&
2578 (!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) {
2579 strcat(userlog, "\r\n");
2580 c_write_str(ssh, userlog);
2581 }
2582 }
2583 }
2584
2585 crWaitUntil(ispkt);
2586
2587 if ((ssh->remote_bugs & BUG_CHOKES_ON_RSA)) {
2588 /* We must not attempt PK auth. Pretend we've already tried it. */
2589 s->tried_publickey = s->tried_agent = 1;
2590 } else {
2591 s->tried_publickey = s->tried_agent = 0;
2592 }
2593 s->tis_auth_refused = s->ccard_auth_refused = 0;
2594 /* Load the public half of ssh->cfg.keyfile so we notice if it's in Pageant */
2595 if (!filename_is_null(ssh->cfg.keyfile)) {
2596 if (!rsakey_pubblob(&ssh->cfg.keyfile,
2597 &s->publickey_blob, &s->publickey_bloblen))
2598 s->publickey_blob = NULL;
2599 } else
2600 s->publickey_blob = NULL;
2601
2602 while (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2603 s->pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
2604
2605 if (agent_exists() && !s->tried_agent) {
2606 /*
2607 * Attempt RSA authentication using Pageant.
2608 */
2609 void *r;
2610
2611 s->authed = FALSE;
2612 s->tried_agent = 1;
2613 logevent("Pageant is running. Requesting keys.");
2614
2615 /* Request the keys held by the agent. */
2616 PUT_32BIT(s->request, 1);
2617 s->request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES;
2618 if (!agent_query(s->request, 5, &r, &s->responselen,
2619 ssh_agent_callback, ssh)) {
2620 do {
2621 crReturn(0);
2622 if (ispkt) {
2623 bombout(("Unexpected data from server while waiting"
2624 " for agent response"));
2625 crStop(0);
2626 }
2627 } while (ispkt || inlen > 0);
2628 r = ssh->agent_response;
2629 s->responselen = ssh->agent_response_len;
2630 }
2631 s->response = (unsigned char *) r;
2632 if (s->response && s->responselen >= 5 &&
2633 s->response[4] == SSH1_AGENT_RSA_IDENTITIES_ANSWER) {
2634 s->p = s->response + 5;
2635 s->nkeys = GET_32BIT(s->p);
2636 s->p += 4;
2637 {
2638 char buf[64];
2639 sprintf(buf, "Pageant has %d SSH1 keys", s->nkeys);
2640 logevent(buf);
2641 }
2642 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
2643 {
2644 char buf[64];
2645 sprintf(buf, "Trying Pageant key #%d", s->keyi);
2646 logevent(buf);
2647 }
2648 if (s->publickey_blob &&
2649 !memcmp(s->p, s->publickey_blob,
2650 s->publickey_bloblen)) {
2651 logevent("This key matches configured key file");
2652 s->tried_publickey = 1;
2653 }
2654 s->p += 4;
2655 s->p += ssh1_read_bignum(s->p, &s->key.exponent);
2656 s->p += ssh1_read_bignum(s->p, &s->key.modulus);
2657 s->commentlen = GET_32BIT(s->p);
2658 s->p += 4;
2659 s->commentp = (char *)s->p;
2660 s->p += s->commentlen;
2661 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
2662 PKT_BIGNUM, s->key.modulus, PKT_END);
2663 crWaitUntil(ispkt);
2664 if (ssh->pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
2665 logevent("Key refused");
2666 continue;
2667 }
2668 logevent("Received RSA challenge");
2669 ssh1_read_bignum(ssh->pktin.body, &s->challenge);
2670 {
2671 char *agentreq, *q, *ret;
2672 void *vret;
2673 int len, retlen;
2674 len = 1 + 4; /* message type, bit count */
2675 len += ssh1_bignum_length(s->key.exponent);
2676 len += ssh1_bignum_length(s->key.modulus);
2677 len += ssh1_bignum_length(s->challenge);
2678 len += 16; /* session id */
2679 len += 4; /* response format */
2680 agentreq = snewn(4 + len, char);
2681 PUT_32BIT(agentreq, len);
2682 q = agentreq + 4;
2683 *q++ = SSH1_AGENTC_RSA_CHALLENGE;
2684 PUT_32BIT(q, bignum_bitcount(s->key.modulus));
2685 q += 4;
2686 q += ssh1_write_bignum(q, s->key.exponent);
2687 q += ssh1_write_bignum(q, s->key.modulus);
2688 q += ssh1_write_bignum(q, s->challenge);
2689 memcpy(q, s->session_id, 16);
2690 q += 16;
2691 PUT_32BIT(q, 1); /* response format */
2692 if (!agent_query(agentreq, len + 4, &vret, &retlen,
2693 ssh_agent_callback, ssh)) {
2694 sfree(agentreq);
2695 do {
2696 crReturn(0);
2697 if (ispkt) {
2698 bombout(("Unexpected data from server"
2699 " while waiting for agent"
2700 " response"));
2701 crStop(0);
2702 }
2703 } while (ispkt || inlen > 0);
2704 vret = ssh->agent_response;
2705 retlen = ssh->agent_response_len;
2706 } else
2707 sfree(agentreq);
2708 ret = vret;
2709 if (ret) {
2710 if (ret[4] == SSH1_AGENT_RSA_RESPONSE) {
2711 logevent("Sending Pageant's response");
2712 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
2713 PKT_DATA, ret + 5, 16,
2714 PKT_END);
2715 sfree(ret);
2716 crWaitUntil(ispkt);
2717 if (ssh->pktin.type == SSH1_SMSG_SUCCESS) {
2718 logevent
2719 ("Pageant's response accepted");
2720 if (flags & FLAG_VERBOSE) {
2721 c_write_str(ssh, "Authenticated using"
2722 " RSA key \"");
2723 c_write(ssh, s->commentp,
2724 s->commentlen);
2725 c_write_str(ssh, "\" from agent\r\n");
2726 }
2727 s->authed = TRUE;
2728 } else
2729 logevent
2730 ("Pageant's response not accepted");
2731 } else {
2732 logevent
2733 ("Pageant failed to answer challenge");
2734 sfree(ret);
2735 }
2736 } else {
2737 logevent("No reply received from Pageant");
2738 }
2739 }
2740 freebn(s->key.exponent);
2741 freebn(s->key.modulus);
2742 freebn(s->challenge);
2743 if (s->authed)
2744 break;
2745 }
2746 }
2747 if (s->authed)
2748 break;
2749 }
2750 if (!filename_is_null(ssh->cfg.keyfile) && !s->tried_publickey)
2751 s->pwpkt_type = SSH1_CMSG_AUTH_RSA;
2752
2753 if (ssh->cfg.try_tis_auth &&
2754 (s->supported_auths_mask & (1 << SSH1_AUTH_TIS)) &&
2755 !s->tis_auth_refused) {
2756 s->pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
2757 logevent("Requested TIS authentication");
2758 send_packet(ssh, SSH1_CMSG_AUTH_TIS, PKT_END);
2759 crWaitUntil(ispkt);
2760 if (ssh->pktin.type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
2761 logevent("TIS authentication declined");
2762 if (flags & FLAG_INTERACTIVE)
2763 c_write_str(ssh, "TIS authentication refused.\r\n");
2764 s->tis_auth_refused = 1;
2765 continue;
2766 } else {
2767 int challengelen = GET_32BIT(ssh->pktin.body);
2768 logevent("Received TIS challenge");
2769 if (challengelen > sizeof(s->prompt) - 1)
2770 challengelen = sizeof(s->prompt) - 1;/* prevent overrun */
2771 memcpy(s->prompt, ssh->pktin.body + 4, challengelen);
2772 /* Prompt heuristic comes from OpenSSH */
2773 strncpy(s->prompt + challengelen,
2774 memchr(s->prompt, '\n', challengelen) ?
2775 "": "\r\nResponse: ",
2776 (sizeof s->prompt) - challengelen);
2777 s->prompt[(sizeof s->prompt) - 1] = '\0';
2778 }
2779 }
2780 if (ssh->cfg.try_tis_auth &&
2781 (s->supported_auths_mask & (1 << SSH1_AUTH_CCARD)) &&
2782 !s->ccard_auth_refused) {
2783 s->pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE;
2784 logevent("Requested CryptoCard authentication");
2785 send_packet(ssh, SSH1_CMSG_AUTH_CCARD, PKT_END);
2786 crWaitUntil(ispkt);
2787 if (ssh->pktin.type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
2788 logevent("CryptoCard authentication declined");
2789 c_write_str(ssh, "CryptoCard authentication refused.\r\n");
2790 s->ccard_auth_refused = 1;
2791 continue;
2792 } else {
2793 int challengelen = GET_32BIT(ssh->pktin.body);
2794 logevent("Received CryptoCard challenge");
2795 if (challengelen > sizeof(s->prompt) - 1)
2796 challengelen = sizeof(s->prompt) - 1;/* prevent overrun */
2797 memcpy(s->prompt, ssh->pktin.body + 4, challengelen);
2798 strncpy(s->prompt + challengelen,
2799 memchr(s->prompt, '\n', challengelen) ?
2800 "" : "\r\nResponse: ",
2801 sizeof(s->prompt) - challengelen);
2802 s->prompt[sizeof(s->prompt) - 1] = '\0';
2803 }
2804 }
2805 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
2806 sprintf(s->prompt, "%.90s@%.90s's password: ",
2807 s->username, ssh->savedhost);
2808 }
2809 if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) {
2810 char *comment = NULL;
2811 int type;
2812 char msgbuf[256];
2813 if (flags & FLAG_VERBOSE)
2814 c_write_str(ssh, "Trying public key authentication.\r\n");
2815 logeventf(ssh, "Trying public key \"%s\"",
2816 filename_to_str(&ssh->cfg.keyfile));
2817 type = key_type(&ssh->cfg.keyfile);
2818 if (type != SSH_KEYTYPE_SSH1) {
2819 sprintf(msgbuf, "Key is of wrong type (%s)",
2820 key_type_to_str(type));
2821 logevent(msgbuf);
2822 c_write_str(ssh, msgbuf);
2823 c_write_str(ssh, "\r\n");
2824 s->tried_publickey = 1;
2825 continue;
2826 }
2827 if (!rsakey_encrypted(&ssh->cfg.keyfile, &comment)) {
2828 if (flags & FLAG_VERBOSE)
2829 c_write_str(ssh, "No passphrase required.\r\n");
2830 goto tryauth;
2831 }
2832 sprintf(s->prompt, "Passphrase for key \"%.100s\": ", comment);
2833 sfree(comment);
2834 }
2835
2836 /*
2837 * Show password prompt, having first obtained it via a TIS
2838 * or CryptoCard exchange if we're doing TIS or CryptoCard
2839 * authentication.
2840 */
2841 if (ssh_get_line) {
2842 if (!ssh_get_line(s->prompt, s->password,
2843 sizeof(s->password), TRUE)) {
2844 /*
2845 * get_line failed to get a password (for example
2846 * because one was supplied on the command line
2847 * which has already failed to work). Terminate.
2848 */
2849 send_packet(ssh, SSH1_MSG_DISCONNECT,
2850 PKT_STR, "No more passwords available to try",
2851 PKT_END);
2852 logevent("Unable to authenticate");
2853 connection_fatal(ssh->frontend, "Unable to authenticate");
2854 ssh_closing((Plug)ssh, NULL, 0, 0);
2855 crStop(1);
2856 }
2857 } else {
2858 /* Prompt may have come from server. We've munged it a bit, so
2859 * we know it to be zero-terminated at least once. */
2860 int ret; /* need not be saved over crReturn */
2861 c_write_untrusted(ssh, s->prompt, strlen(s->prompt));
2862 s->pos = 0;
2863
2864 setup_userpass_input(ssh, s->password, sizeof(s->password), 0);
2865 do {
2866 crWaitUntil(!ispkt);
2867 ret = process_userpass_input(ssh, in, inlen);
2868 } while (ret == 0);
2869 if (ret < 0)
2870 cleanup_exit(0);
2871 c_write_str(ssh, "\r\n");
2872 }
2873
2874 tryauth:
2875 if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) {
2876 /*
2877 * Try public key authentication with the specified
2878 * key file.
2879 */
2880 s->tried_publickey = 1;
2881
2882 {
2883 int ret = loadrsakey(&ssh->cfg.keyfile, &s->key, s->password);
2884 if (ret == 0) {
2885 c_write_str(ssh, "Couldn't load private key from ");
2886 c_write_str(ssh, filename_to_str(&ssh->cfg.keyfile));
2887 c_write_str(ssh, ".\r\n");
2888 continue; /* go and try password */
2889 }
2890 if (ret == -1) {
2891 c_write_str(ssh, "Wrong passphrase.\r\n");
2892 s->tried_publickey = 0;
2893 continue; /* try again */
2894 }
2895 }
2896
2897 /*
2898 * Send a public key attempt.
2899 */
2900 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
2901 PKT_BIGNUM, s->key.modulus, PKT_END);
2902
2903 crWaitUntil(ispkt);
2904 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2905 c_write_str(ssh, "Server refused our public key.\r\n");
2906 continue; /* go and try password */
2907 }
2908 if (ssh->pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
2909 bombout(("Bizarre response to offer of public key"));
2910 crStop(0);
2911 }
2912
2913 {
2914 int i;
2915 unsigned char buffer[32];
2916 Bignum challenge, response;
2917
2918 ssh1_read_bignum(ssh->pktin.body, &challenge);
2919 response = rsadecrypt(challenge, &s->key);
2920 freebn(s->key.private_exponent);/* burn the evidence */
2921
2922 for (i = 0; i < 32; i++) {
2923 buffer[i] = bignum_byte(response, 31 - i);
2924 }
2925
2926 MD5Init(&md5c);
2927 MD5Update(&md5c, buffer, 32);
2928 MD5Update(&md5c, s->session_id, 16);
2929 MD5Final(buffer, &md5c);
2930
2931 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
2932 PKT_DATA, buffer, 16, PKT_END);
2933
2934 freebn(challenge);
2935 freebn(response);
2936 }
2937
2938 crWaitUntil(ispkt);
2939 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2940 if (flags & FLAG_VERBOSE)
2941 c_write_str(ssh, "Failed to authenticate with"
2942 " our public key.\r\n");
2943 continue; /* go and try password */
2944 } else if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
2945 bombout(("Bizarre response to RSA authentication response"));
2946 crStop(0);
2947 }
2948
2949 break; /* we're through! */
2950 } else {
2951 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
2952 /*
2953 * Defence against traffic analysis: we send a
2954 * whole bunch of packets containing strings of
2955 * different lengths. One of these strings is the
2956 * password, in a SSH1_CMSG_AUTH_PASSWORD packet.
2957 * The others are all random data in
2958 * SSH1_MSG_IGNORE packets. This way a passive
2959 * listener can't tell which is the password, and
2960 * hence can't deduce the password length.
2961 *
2962 * Anybody with a password length greater than 16
2963 * bytes is going to have enough entropy in their
2964 * password that a listener won't find it _that_
2965 * much help to know how long it is. So what we'll
2966 * do is:
2967 *
2968 * - if password length < 16, we send 15 packets
2969 * containing string lengths 1 through 15
2970 *
2971 * - otherwise, we let N be the nearest multiple
2972 * of 8 below the password length, and send 8
2973 * packets containing string lengths N through
2974 * N+7. This won't obscure the order of
2975 * magnitude of the password length, but it will
2976 * introduce a bit of extra uncertainty.
2977 *
2978 * A few servers (the old 1.2.18 through 1.2.22)
2979 * can't deal with SSH1_MSG_IGNORE. For these
2980 * servers, we need an alternative defence. We make
2981 * use of the fact that the password is interpreted
2982 * as a C string: so we can append a NUL, then some
2983 * random data.
2984 *
2985 * One server (a Cisco one) can deal with neither
2986 * SSH1_MSG_IGNORE _nor_ a padded password string.
2987 * For this server we are left with no defences
2988 * against password length sniffing.
2989 */
2990 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE)) {
2991 /*
2992 * The server can deal with SSH1_MSG_IGNORE, so
2993 * we can use the primary defence.
2994 */
2995 int bottom, top, pwlen, i;
2996 char *randomstr;
2997
2998 pwlen = strlen(s->password);
2999 if (pwlen < 16) {
3000 bottom = 0; /* zero length passwords are OK! :-) */
3001 top = 15;
3002 } else {
3003 bottom = pwlen & ~7;
3004 top = bottom + 7;
3005 }
3006
3007 assert(pwlen >= bottom && pwlen <= top);
3008
3009 randomstr = snewn(top + 1, char);
3010
3011 for (i = bottom; i <= top; i++) {
3012 if (i == pwlen)
3013 defer_packet(ssh, s->pwpkt_type,
3014 PKT_STR, s->password, PKT_END);
3015 else {
3016 for (j = 0; j < i; j++) {
3017 do {
3018 randomstr[j] = random_byte();
3019 } while (randomstr[j] == '\0');
3020 }
3021 randomstr[i] = '\0';
3022 defer_packet(ssh, SSH1_MSG_IGNORE,
3023 PKT_STR, randomstr, PKT_END);
3024 }
3025 }
3026 logevent("Sending password with camouflage packets");
3027 ssh_pkt_defersend(ssh);
3028 }
3029 else if (!(ssh->remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) {
3030 /*
3031 * The server can't deal with SSH1_MSG_IGNORE
3032 * but can deal with padded passwords, so we
3033 * can use the secondary defence.
3034 */
3035 char string[64];
3036 char *ss;
3037 int len;
3038
3039 len = strlen(s->password);
3040 if (len < sizeof(string)) {
3041 ss = string;
3042 strcpy(string, s->password);
3043 len++; /* cover the zero byte */
3044 while (len < sizeof(string)) {
3045 string[len++] = (char) random_byte();
3046 }
3047 } else {
3048 ss = s->password;
3049 }
3050 logevent("Sending length-padded password");
3051 send_packet(ssh, s->pwpkt_type, PKT_INT, len,
3052 PKT_DATA, ss, len, PKT_END);
3053 } else {
3054 /*
3055 * The server has _both_
3056 * BUG_CHOKES_ON_SSH1_IGNORE and
3057 * BUG_NEEDS_SSH1_PLAIN_PASSWORD. There is
3058 * therefore nothing we can do.
3059 */
3060 int len;
3061 len = strlen(s->password);
3062 logevent("Sending unpadded password");
3063 send_packet(ssh, s->pwpkt_type, PKT_INT, len,
3064 PKT_DATA, s->password, len, PKT_END);
3065 }
3066 } else {
3067 send_packet(ssh, s->pwpkt_type, PKT_STR, s->password, PKT_END);
3068 }
3069 }
3070 logevent("Sent password");
3071 memset(s->password, 0, strlen(s->password));
3072 crWaitUntil(ispkt);
3073 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3074 if (flags & FLAG_VERBOSE)
3075 c_write_str(ssh, "Access denied\r\n");
3076 logevent("Authentication refused");
3077 } else if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
3078 bombout(("Strange packet received, type %d", ssh->pktin.type));
3079 crStop(0);
3080 }
3081 }
3082
3083 logevent("Authentication successful");
3084
3085 crFinish(1);
3086 }
3087
3088 void sshfwd_close(struct ssh_channel *c)
3089 {
3090 Ssh ssh = c->ssh;
3091
3092 if (ssh->state != SSH_STATE_SESSION) {
3093 assert(ssh->state == SSH_STATE_CLOSED);
3094 return;
3095 }
3096
3097 if (c && !c->closes) {
3098 /*
3099 * If the channel's remoteid is -1, we have sent
3100 * CHANNEL_OPEN for this channel, but it hasn't even been
3101 * acknowledged by the server. So we must set a close flag
3102 * on it now, and then when the server acks the channel
3103 * open, we can close it then.
3104 */
3105 if (((int)c->remoteid) != -1) {
3106 if (ssh->version == 1) {
3107 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid,
3108 PKT_END);
3109 } else {
3110 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
3111 ssh2_pkt_adduint32(ssh, c->remoteid);
3112 ssh2_pkt_send(ssh);
3113 }
3114 }
3115 c->closes = 1; /* sent MSG_CLOSE */
3116 if (c->type == CHAN_X11) {
3117 c->u.x11.s = NULL;
3118 logevent("Forwarded X11 connection terminated");
3119 } else if (c->type == CHAN_SOCKDATA ||
3120 c->type == CHAN_SOCKDATA_DORMANT) {
3121 c->u.pfd.s = NULL;
3122 logevent("Forwarded port closed");
3123 }
3124 }
3125 }
3126
3127 int sshfwd_write(struct ssh_channel *c, char *buf, int len)
3128 {
3129 Ssh ssh = c->ssh;
3130
3131 if (ssh->state != SSH_STATE_SESSION) {
3132 assert(ssh->state == SSH_STATE_CLOSED);
3133 return 0;
3134 }
3135
3136 if (ssh->version == 1) {
3137 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
3138 PKT_INT, c->remoteid,
3139 PKT_INT, len, PKT_DATA, buf, len, PKT_END);
3140 /*
3141 * In SSH1 we can return 0 here - implying that forwarded
3142 * connections are never individually throttled - because
3143 * the only circumstance that can cause throttling will be
3144 * the whole SSH connection backing up, in which case
3145 * _everything_ will be throttled as a whole.
3146 */
3147 return 0;
3148 } else {
3149 ssh2_add_channel_data(c, buf, len);
3150 return ssh2_try_send(c);
3151 }
3152 }
3153
3154 void sshfwd_unthrottle(struct ssh_channel *c, int bufsize)
3155 {
3156 Ssh ssh = c->ssh;
3157
3158 if (ssh->state != SSH_STATE_SESSION) {
3159 assert(ssh->state == SSH_STATE_CLOSED);
3160 return;
3161 }
3162
3163 if (ssh->version == 1) {
3164 if (c->v.v1.throttling && bufsize < SSH1_BUFFER_LIMIT) {
3165 c->v.v1.throttling = 0;
3166 ssh1_throttle(ssh, -1);
3167 }
3168 } else {
3169 ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
3170 }
3171 }
3172
3173 static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
3174 {
3175 crBegin(ssh->ssh1_protocol_crstate);
3176
3177 random_init();
3178
3179 while (!do_ssh1_login(ssh, in, inlen, ispkt)) {
3180 crReturnV;
3181 }
3182 if (ssh->state == SSH_STATE_CLOSED)
3183 crReturnV;
3184
3185 if (ssh->cfg.agentfwd && agent_exists()) {
3186 logevent("Requesting agent forwarding");
3187 send_packet(ssh, SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END);
3188 do {
3189 crReturnV;
3190 } while (!ispkt);
3191 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3192 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3193 bombout(("Protocol confusion"));
3194 crStopV;
3195 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3196 logevent("Agent forwarding refused");
3197 } else {
3198 logevent("Agent forwarding enabled");
3199 ssh->agentfwd_enabled = TRUE;
3200 }
3201 }
3202
3203 if (ssh->cfg.x11_forward) {
3204 char proto[20], data[64];
3205 logevent("Requesting X11 forwarding");
3206 ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
3207 data, sizeof(data), ssh->cfg.x11_auth);
3208 x11_get_real_auth(ssh->x11auth, ssh->cfg.x11_display);
3209 if (ssh->v1_local_protoflags & SSH1_PROTOFLAG_SCREEN_NUMBER) {
3210 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
3211 PKT_STR, proto, PKT_STR, data,
3212 PKT_INT, x11_get_screen_number(ssh->cfg.x11_display),
3213 PKT_END);
3214 } else {
3215 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
3216 PKT_STR, proto, PKT_STR, data, PKT_END);
3217 }
3218 do {
3219 crReturnV;
3220 } while (!ispkt);
3221 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3222 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3223 bombout(("Protocol confusion"));
3224 crStopV;
3225 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3226 logevent("X11 forwarding refused");
3227 } else {
3228 logevent("X11 forwarding enabled");
3229 ssh->X11_fwd_enabled = TRUE;
3230 }
3231 }
3232
3233 {
3234 char type;
3235 int n;
3236 int sport,dport,sserv,dserv;
3237 char sports[256], dports[256], saddr[256], host[256];
3238
3239 ssh->rportfwds = newtree234(ssh_rportcmp_ssh1);
3240 /* Add port forwardings. */
3241 ssh->portfwd_strptr = ssh->cfg.portfwd;
3242 while (*ssh->portfwd_strptr) {
3243 type = *ssh->portfwd_strptr++;
3244 saddr[0] = '\0';
3245 n = 0;
3246 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != '\t') {
3247 if (*ssh->portfwd_strptr == ':') {
3248 /*
3249 * We've seen a colon in the middle of the
3250 * source port number. This means that
3251 * everything we've seen until now is the
3252 * source _address_, so we'll move it into
3253 * saddr and start sports from the beginning
3254 * again.
3255 */
3256 ssh->portfwd_strptr++;
3257 sports[n] = '\0';
3258 strcpy(saddr, sports);
3259 n = 0;
3260 }
3261 if (n < 255) sports[n++] = *ssh->portfwd_strptr++;
3262 }
3263 sports[n] = 0;
3264 if (type != 'D') {
3265 if (*ssh->portfwd_strptr == '\t')
3266 ssh->portfwd_strptr++;
3267 n = 0;
3268 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':') {
3269 if (n < 255) host[n++] = *ssh->portfwd_strptr++;
3270 }
3271 host[n] = 0;
3272 if (*ssh->portfwd_strptr == ':')
3273 ssh->portfwd_strptr++;
3274 n = 0;
3275 while (*ssh->portfwd_strptr) {
3276 if (n < 255) dports[n++] = *ssh->portfwd_strptr++;
3277 }
3278 dports[n] = 0;
3279 ssh->portfwd_strptr++;
3280 dport = atoi(dports);
3281 dserv = 0;
3282 if (dport == 0) {
3283 dserv = 1;
3284 dport = net_service_lookup(dports);
3285 if (!dport) {
3286 logeventf(ssh, "Service lookup failed for"
3287 " destination port \"%s\"", dports);
3288 }
3289 }
3290 } else {
3291 while (*ssh->portfwd_strptr) ssh->portfwd_strptr++;
3292 dport = dserv = -1;
3293 }
3294 sport = atoi(sports);
3295 sserv = 0;
3296 if (sport == 0) {
3297 sserv = 1;
3298 sport = net_service_lookup(sports);
3299 if (!sport) {
3300 logeventf(ssh, "Service lookup failed for source"
3301 " port \"%s\"", sports);
3302 }
3303 }
3304 if (sport && dport) {
3305 if (type == 'L') {
3306 pfd_addforward(host, dport, *saddr ? saddr : NULL,
3307 sport, ssh, &ssh->cfg);
3308 logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
3309 " forwarding to %s:%.*s%.*s%d%.*s",
3310 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
3311 (int)(*saddr?1:0), ":",
3312 (int)(sserv ? strlen(sports) : 0), sports,
3313 sserv, "(", sport, sserv, ")",
3314 host,
3315 (int)(dserv ? strlen(dports) : 0), dports,
3316 dserv, "(", dport, dserv, ")");
3317 } else if (type == 'D') {
3318 pfd_addforward(NULL, -1, *saddr ? saddr : NULL,
3319 sport, ssh, &ssh->cfg);
3320 logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
3321 " doing SOCKS dynamic forwarding",
3322 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
3323 (int)(*saddr?1:0), ":",
3324 (int)(sserv ? strlen(sports) : 0), sports,
3325 sserv, "(", sport, sserv, ")");
3326 } else {
3327 struct ssh_rportfwd *pf;
3328 pf = snew(struct ssh_rportfwd);
3329 strcpy(pf->dhost, host);
3330 pf->dport = dport;
3331 if (saddr) {
3332 logeventf(ssh,
3333 "SSH1 cannot handle source address spec \"%s:%d\"; ignoring",
3334 saddr, sport);
3335 }
3336 if (add234(ssh->rportfwds, pf) != pf) {
3337 logeventf(ssh,
3338 "Duplicate remote port forwarding to %s:%d",
3339 host, dport);
3340 sfree(pf);
3341 } else {
3342 logeventf(ssh, "Requesting remote port %.*s%.*s%d%.*s"
3343 " forward to %s:%.*s%.*s%d%.*s",
3344 (int)(sserv ? strlen(sports) : 0), sports,
3345 sserv, "(", sport, sserv, ")",
3346 host,
3347 (int)(dserv ? strlen(dports) : 0), dports,
3348 dserv, "(", dport, dserv, ")");
3349 send_packet(ssh, SSH1_CMSG_PORT_FORWARD_REQUEST,
3350 PKT_INT, sport,
3351 PKT_STR, host,
3352 PKT_INT, dport,
3353 PKT_END);
3354 do {
3355 crReturnV;
3356 } while (!ispkt);
3357 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3358 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3359 bombout(("Protocol confusion"));
3360 crStopV;
3361 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3362 c_write_str(ssh, "Server refused port"
3363 " forwarding\r\n");
3364 }
3365 logevent("Remote port forwarding enabled");
3366 }
3367 }
3368 }
3369 }
3370 }
3371
3372 if (!ssh->cfg.nopty) {
3373 send_packet(ssh, SSH1_CMSG_REQUEST_PTY,
3374 PKT_STR, ssh->cfg.termtype,
3375 PKT_INT, ssh->term_height,
3376 PKT_INT, ssh->term_width,
3377 PKT_INT, 0, PKT_INT, 0, PKT_CHAR, 0, PKT_END);
3378 ssh->state = SSH_STATE_INTERMED;
3379 do {
3380 crReturnV;
3381 } while (!ispkt);
3382 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3383 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3384 bombout(("Protocol confusion"));
3385 crStopV;
3386 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3387 c_write_str(ssh, "Server refused to allocate pty\r\n");
3388 ssh->editing = ssh->echoing = 1;
3389 }
3390 logevent("Allocated pty");
3391 } else {
3392 ssh->editing = ssh->echoing = 1;
3393 }
3394
3395 if (ssh->cfg.compression) {
3396 send_packet(ssh, SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END);
3397 do {
3398 crReturnV;
3399 } while (!ispkt);
3400 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3401 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3402 bombout(("Protocol confusion"));
3403 crStopV;
3404 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3405 c_write_str(ssh, "Server refused to compress\r\n");
3406 }
3407 logevent("Started compression");
3408 ssh->v1_compressing = TRUE;
3409 ssh->cs_comp_ctx = zlib_compress_init();
3410 logevent("Initialised zlib (RFC1950) compression");
3411 ssh->sc_comp_ctx = zlib_decompress_init();
3412 logevent("Initialised zlib (RFC1950) decompression");
3413 }
3414
3415 /*
3416 * Start the shell or command.
3417 *
3418 * Special case: if the first-choice command is an SSH2
3419 * subsystem (hence not usable here) and the second choice
3420 * exists, we fall straight back to that.
3421 */
3422 {
3423 char *cmd = ssh->cfg.remote_cmd_ptr;
3424
3425 if (ssh->cfg.ssh_subsys && ssh->cfg.remote_cmd_ptr2) {
3426 cmd = ssh->cfg.remote_cmd_ptr2;
3427 ssh->fallback_cmd = TRUE;
3428 }
3429 if (*cmd)
3430 send_packet(ssh, SSH1_CMSG_EXEC_CMD, PKT_STR, cmd, PKT_END);
3431 else
3432 send_packet(ssh, SSH1_CMSG_EXEC_SHELL, PKT_END);
3433 logevent("Started session");
3434 }
3435
3436 ssh->state = SSH_STATE_SESSION;
3437 if (ssh->size_needed)
3438 ssh_size(ssh, ssh->term_width, ssh->term_height);
3439 if (ssh->eof_needed)
3440 ssh_special(ssh, TS_EOF);
3441
3442 if (ssh->ldisc)
3443 ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */
3444 ssh->send_ok = 1;
3445 ssh->channels = newtree234(ssh_channelcmp);
3446 while (1) {
3447 crReturnV;
3448 if (ispkt) {
3449 if (ssh->pktin.type == SSH1_SMSG_STDOUT_DATA ||
3450 ssh->pktin.type == SSH1_SMSG_STDERR_DATA) {
3451 long len = GET_32BIT(ssh->pktin.body);
3452 int bufsize =
3453 from_backend(ssh->frontend,
3454 ssh->pktin.type == SSH1_SMSG_STDERR_DATA,
3455 (char *)(ssh->pktin.body) + 4, len);
3456 if (!ssh->v1_stdout_throttling && bufsize > SSH1_BUFFER_LIMIT) {
3457 ssh->v1_stdout_throttling = 1;
3458 ssh1_throttle(ssh, +1);
3459 }
3460 } else if (ssh->pktin.type == SSH1_MSG_DISCONNECT) {
3461 ssh_closing((Plug)ssh, NULL, 0, 0);
3462 logevent("Received disconnect request");
3463 crStopV;
3464 } else if (ssh->pktin.type == SSH1_SMSG_X11_OPEN) {
3465 /* Remote side is trying to open a channel to talk to our
3466 * X-Server. Give them back a local channel number. */
3467 struct ssh_channel *c;
3468
3469 logevent("Received X11 connect request");
3470 /* Refuse if X11 forwarding is disabled. */
3471 if (!ssh->X11_fwd_enabled) {
3472 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3473 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
3474 logevent("Rejected X11 connect request");
3475 } else {
3476 c = snew(struct ssh_channel);
3477 c->ssh = ssh;
3478
3479 if (x11_init(&c->u.x11.s, ssh->cfg.x11_display, c,
3480 ssh->x11auth, NULL, -1, &ssh->cfg) != NULL) {
3481 logevent("opening X11 forward connection failed");
3482 sfree(c);
3483 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3484 PKT_INT, GET_32BIT(ssh->pktin.body),
3485 PKT_END);
3486 } else {
3487 logevent
3488 ("opening X11 forward connection succeeded");
3489 c->remoteid = GET_32BIT(ssh->pktin.body);
3490 c->localid = alloc_channel_id(ssh);
3491 c->closes = 0;
3492 c->v.v1.throttling = 0;
3493 c->type = CHAN_X11; /* identify channel type */
3494 add234(ssh->channels, c);
3495 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3496 PKT_INT, c->remoteid, PKT_INT,
3497 c->localid, PKT_END);
3498 logevent("Opened X11 forward channel");
3499 }
3500 }
3501 } else if (ssh->pktin.type == SSH1_SMSG_AGENT_OPEN) {
3502 /* Remote side is trying to open a channel to talk to our
3503 * agent. Give them back a local channel number. */
3504 struct ssh_channel *c;
3505
3506 /* Refuse if agent forwarding is disabled. */
3507 if (!ssh->agentfwd_enabled) {
3508 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3509 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
3510 } else {
3511 c = snew(struct ssh_channel);
3512 c->ssh = ssh;
3513 c->remoteid = GET_32BIT(ssh->pktin.body);
3514 c->localid = alloc_channel_id(ssh);
3515 c->closes = 0;
3516 c->v.v1.throttling = 0;
3517 c->type = CHAN_AGENT; /* identify channel type */
3518 c->u.a.lensofar = 0;
3519 add234(ssh->channels, c);
3520 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3521 PKT_INT, c->remoteid, PKT_INT, c->localid,
3522 PKT_END);
3523 }
3524 } else if (ssh->pktin.type == SSH1_MSG_PORT_OPEN) {
3525 /* Remote side is trying to open a channel to talk to a
3526 * forwarded port. Give them back a local channel number. */
3527 struct ssh_channel *c;
3528 struct ssh_rportfwd pf;
3529 int hostsize, port;
3530 char host[256], buf[1024];
3531 char *p, *h, *e;
3532 c = snew(struct ssh_channel);
3533 c->ssh = ssh;
3534
3535 hostsize = GET_32BIT(ssh->pktin.body+4);
3536 for (h = host, p = (char *)(ssh->pktin.body+8);
3537 hostsize != 0; hostsize--) {
3538 if (h+1 < host+sizeof(host))
3539 *h++ = *p;
3540 p++;
3541 }
3542 *h = 0;
3543 port = GET_32BIT(p);
3544
3545 strcpy(pf.dhost, host);
3546 pf.dport = port;
3547
3548 if (find234(ssh->rportfwds, &pf, NULL) == NULL) {
3549 sprintf(buf, "Rejected remote port open request for %s:%d",
3550 host, port);
3551 logevent(buf);
3552 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3553 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
3554 } else {
3555 sprintf(buf, "Received remote port open request for %s:%d",
3556 host, port);
3557 logevent(buf);
3558 e = pfd_newconnect(&c->u.pfd.s, host, port, c, &ssh->cfg);
3559 if (e != NULL) {
3560 char buf[256];
3561 sprintf(buf, "Port open failed: %s", e);
3562 logevent(buf);
3563 sfree(c);
3564 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3565 PKT_INT, GET_32BIT(ssh->pktin.body),
3566 PKT_END);
3567 } else {
3568 c->remoteid = GET_32BIT(ssh->pktin.body);
3569 c->localid = alloc_channel_id(ssh);
3570 c->closes = 0;
3571 c->v.v1.throttling = 0;
3572 c->type = CHAN_SOCKDATA; /* identify channel type */
3573 add234(ssh->channels, c);
3574 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3575 PKT_INT, c->remoteid, PKT_INT,
3576 c->localid, PKT_END);
3577 logevent("Forwarded port opened successfully");
3578 }
3579 }
3580
3581 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_OPEN_CONFIRMATION) {
3582 unsigned int remoteid = GET_32BIT(ssh->pktin.body);
3583 unsigned int localid = GET_32BIT(ssh->pktin.body+4);
3584 struct ssh_channel *c;
3585
3586 c = find234(ssh->channels, &remoteid, ssh_channelfind);
3587 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
3588 c->remoteid = localid;
3589 c->type = CHAN_SOCKDATA;
3590 c->v.v1.throttling = 0;
3591 pfd_confirm(c->u.pfd.s);
3592 }
3593
3594 if (c && c->closes) {
3595 /*
3596 * We have a pending close on this channel,
3597 * which we decided on before the server acked
3598 * the channel open. So now we know the
3599 * remoteid, we can close it again.
3600 */
3601 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE,
3602 PKT_INT, c->remoteid, PKT_END);
3603 }
3604
3605 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_OPEN_FAILURE) {
3606 unsigned int remoteid = GET_32BIT(ssh->pktin.body);
3607 struct ssh_channel *c;
3608
3609 c = find234(ssh->channels, &remoteid, ssh_channelfind);
3610 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
3611 logevent("Forwarded connection refused by server");
3612 pfd_close(c->u.pfd.s);
3613 del234(ssh->channels, c);
3614 sfree(c);
3615 }
3616
3617 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ||
3618 ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION) {
3619 /* Remote side closes a channel. */
3620 unsigned i = GET_32BIT(ssh->pktin.body);
3621 struct ssh_channel *c;
3622 c = find234(ssh->channels, &i, ssh_channelfind);
3623 if (c && ((int)c->remoteid) != -1) {
3624 int closetype;
3625 closetype =
3626 (ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ? 1 : 2);
3627
3628 if ((c->closes == 0) && (c->type == CHAN_X11)) {
3629 logevent("Forwarded X11 connection terminated");
3630 assert(c->u.x11.s != NULL);
3631 x11_close(c->u.x11.s);
3632 c->u.x11.s = NULL;
3633 }
3634 if ((c->closes == 0) && (c->type == CHAN_SOCKDATA)) {
3635 logevent("Forwarded port closed");
3636 assert(c->u.pfd.s != NULL);
3637 pfd_close(c->u.pfd.s);
3638 c->u.pfd.s = NULL;
3639 }
3640
3641 c->closes |= (closetype << 2); /* seen this message */
3642 if (!(c->closes & closetype)) {
3643 send_packet(ssh, ssh->pktin.type, PKT_INT, c->remoteid,
3644 PKT_END);
3645 c->closes |= closetype; /* sent it too */
3646 }
3647
3648 if (c->closes == 15) {
3649 del234(ssh->channels, c);
3650 sfree(c);
3651 }
3652 } else {
3653 bombout(("Received CHANNEL_CLOSE%s for %s channel %d\n",
3654 ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ? "" :
3655 "_CONFIRMATION", c ? "half-open" : "nonexistent",
3656 i));
3657 crStopV;
3658 }
3659 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_DATA) {
3660 /* Data sent down one of our channels. */
3661 int i = GET_32BIT(ssh->pktin.body);
3662 int len = GET_32BIT(ssh->pktin.body + 4);
3663 unsigned char *p = ssh->pktin.body + 8;
3664 struct ssh_channel *c;
3665 c = find234(ssh->channels, &i, ssh_channelfind);
3666 if (c) {
3667 int bufsize = 0;
3668 switch (c->type) {
3669 case CHAN_X11:
3670 bufsize = x11_send(c->u.x11.s, (char *)p, len);
3671 break;
3672 case CHAN_SOCKDATA:
3673 bufsize = pfd_send(c->u.pfd.s, (char *)p, len);
3674 break;
3675 case CHAN_AGENT:
3676 /* Data for an agent message. Buffer it. */
3677 while (len > 0) {
3678 if (c->u.a.lensofar < 4) {
3679 int l = min(4 - c->u.a.lensofar, len);
3680 memcpy(c->u.a.msglen + c->u.a.lensofar, p,
3681 l);
3682 p += l;
3683 len -= l;
3684 c->u.a.lensofar += l;
3685 }
3686 if (c->u.a.lensofar == 4) {
3687 c->u.a.totallen =
3688 4 + GET_32BIT(c->u.a.msglen);
3689 c->u.a.message = snewn(c->u.a.totallen,
3690 unsigned char);
3691 memcpy(c->u.a.message, c->u.a.msglen, 4);
3692 }
3693 if (c->u.a.lensofar >= 4 && len > 0) {
3694 int l =
3695 min(c->u.a.totallen - c->u.a.lensofar,
3696 len);
3697 memcpy(c->u.a.message + c->u.a.lensofar, p,
3698 l);
3699 p += l;
3700 len -= l;
3701 c->u.a.lensofar += l;
3702 }
3703 if (c->u.a.lensofar == c->u.a.totallen) {
3704 void *reply;
3705 int replylen;
3706 if (agent_query(c->u.a.message,
3707 c->u.a.totallen,
3708 &reply, &replylen,
3709 ssh_agentf_callback, c))
3710 ssh_agentf_callback(c, reply, replylen);
3711 sfree(c->u.a.message);
3712 c->u.a.lensofar = 0;
3713 }
3714 }
3715 bufsize = 0; /* agent channels never back up */
3716 break;
3717 }
3718 if (!c->v.v1.throttling && bufsize > SSH1_BUFFER_LIMIT) {
3719 c->v.v1.throttling = 1;
3720 ssh1_throttle(ssh, +1);
3721 }
3722 }
3723 } else if (ssh->pktin.type == SSH1_SMSG_SUCCESS) {
3724 /* may be from EXEC_SHELL on some servers */
3725 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3726 /* may be from EXEC_SHELL on some servers
3727 * if no pty is available or in other odd cases. Ignore */
3728 } else if (ssh->pktin.type == SSH1_SMSG_EXIT_STATUS) {
3729 char buf[100];
3730 ssh->exitcode = GET_32BIT(ssh->pktin.body);
3731 sprintf(buf, "Server sent command exit status %d",
3732 ssh->exitcode);
3733 logevent(buf);
3734 send_packet(ssh, SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
3735 /*
3736 * In case `helpful' firewalls or proxies tack
3737 * extra human-readable text on the end of the
3738 * session which we might mistake for another
3739 * encrypted packet, we close the session once
3740 * we've sent EXIT_CONFIRMATION.
3741 */
3742 ssh_closing((Plug)ssh, NULL, 0, 0);
3743 crStopV;
3744 } else {
3745 bombout(("Strange packet received: type %d", ssh->pktin.type));
3746 crStopV;
3747 }
3748 } else {
3749 while (inlen > 0) {
3750 int len = min(inlen, 512);
3751 send_packet(ssh, SSH1_CMSG_STDIN_DATA,
3752 PKT_INT, len, PKT_DATA, in, len, PKT_END);
3753 in += len;
3754 inlen -= len;
3755 }
3756 }
3757 }
3758
3759 crFinishV;
3760 }
3761
3762 /*
3763 * Utility routine for decoding comma-separated strings in KEXINIT.
3764 */
3765 static int in_commasep_string(char *needle, char *haystack, int haylen)
3766 {
3767 int needlen;
3768 if (!needle || !haystack) /* protect against null pointers */
3769 return 0;
3770 needlen = strlen(needle);
3771 while (1) {
3772 /*
3773 * Is it at the start of the string?
3774 */
3775 if (haylen >= needlen && /* haystack is long enough */
3776 !memcmp(needle, haystack, needlen) && /* initial match */
3777 (haylen == needlen || haystack[needlen] == ',')
3778 /* either , or EOS follows */
3779 )
3780 return 1;
3781 /*
3782 * If not, search for the next comma and resume after that.
3783 * If no comma found, terminate.
3784 */
3785 while (haylen > 0 && *haystack != ',')
3786 haylen--, haystack++;
3787 if (haylen == 0)
3788 return 0;
3789 haylen--, haystack++; /* skip over comma itself */
3790 }
3791 }
3792
3793 /*
3794 * SSH2 key creation method.
3795 */
3796 static void ssh2_mkkey(Ssh ssh, Bignum K, unsigned char *H,
3797 unsigned char *sessid, char chr,
3798 unsigned char *keyspace)
3799 {
3800 SHA_State s;
3801 /* First 20 bytes. */
3802 SHA_Init(&s);
3803 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
3804 sha_mpint(&s, K);
3805 SHA_Bytes(&s, H, 20);
3806 SHA_Bytes(&s, &chr, 1);
3807 SHA_Bytes(&s, sessid, 20);
3808 SHA_Final(&s, keyspace);
3809 /* Next 20 bytes. */
3810 SHA_Init(&s);
3811 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
3812 sha_mpint(&s, K);
3813 SHA_Bytes(&s, H, 20);
3814 SHA_Bytes(&s, keyspace, 20);
3815 SHA_Final(&s, keyspace + 20);
3816 }
3817
3818 /*
3819 * Handle the SSH2 transport layer.
3820 */
3821 static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
3822 {
3823 struct do_ssh2_transport_state {
3824 int nbits, pbits, warn;
3825 Bignum p, g, e, f, K;
3826 int kex_init_value, kex_reply_value;
3827 const struct ssh_mac **maclist;
3828 int nmacs;
3829 const struct ssh2_cipher *cscipher_tobe;
3830 const struct ssh2_cipher *sccipher_tobe;
3831 const struct ssh_mac *csmac_tobe;
3832 const struct ssh_mac *scmac_tobe;
3833 const struct ssh_compress *cscomp_tobe;
3834 const struct ssh_compress *sccomp_tobe;
3835 char *hostkeydata, *sigdata, *keystr, *fingerprint;
3836 int hostkeylen, siglen;
3837 void *hkey; /* actual host key */
3838 unsigned char exchange_hash[20];
3839 int n_preferred_ciphers;
3840 const struct ssh2_ciphers *preferred_ciphers[CIPHER_MAX];
3841 const struct ssh_compress *preferred_comp;
3842 int first_kex;
3843 };
3844 crState(do_ssh2_transport_state);
3845
3846 crBegin(ssh->do_ssh2_transport_crstate);
3847
3848 s->cscipher_tobe = s->sccipher_tobe = NULL;
3849 s->csmac_tobe = s->scmac_tobe = NULL;
3850 s->cscomp_tobe = s->sccomp_tobe = NULL;
3851
3852 random_init();
3853 s->first_kex = 1;
3854
3855 {
3856 int i;
3857 /*
3858 * Set up the preferred ciphers. (NULL => warn below here)
3859 */
3860 s->n_preferred_ciphers = 0;
3861 for (i = 0; i < CIPHER_MAX; i++) {
3862 switch (ssh->cfg.ssh_cipherlist[i]) {
3863 case CIPHER_BLOWFISH:
3864 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_blowfish;
3865 break;
3866 case CIPHER_DES:
3867 if (ssh->cfg.ssh2_des_cbc) {
3868 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_des;
3869 }
3870 break;
3871 case CIPHER_3DES:
3872 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_3des;
3873 break;
3874 case CIPHER_AES:
3875 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_aes;
3876 break;
3877 case CIPHER_WARN:
3878 /* Flag for later. Don't bother if it's the last in
3879 * the list. */
3880 if (i < CIPHER_MAX - 1) {
3881 s->preferred_ciphers[s->n_preferred_ciphers++] = NULL;
3882 }
3883 break;
3884 }
3885 }
3886 }
3887
3888 /*
3889 * Set up preferred compression.
3890 */
3891 if (ssh->cfg.compression)
3892 s->preferred_comp = &ssh_zlib;
3893 else
3894 s->preferred_comp = &ssh_comp_none;
3895
3896 /*
3897 * Be prepared to work around the buggy MAC problem.
3898 */
3899 if (ssh->remote_bugs & BUG_SSH2_HMAC)
3900 s->maclist = buggymacs, s->nmacs = lenof(buggymacs);
3901 else
3902 s->maclist = macs, s->nmacs = lenof(macs);
3903
3904 begin_key_exchange:
3905 {
3906 int i, j, cipherstr_started;
3907
3908 /*
3909 * Construct and send our key exchange packet.
3910 */
3911 ssh2_pkt_init(ssh, SSH2_MSG_KEXINIT);
3912 for (i = 0; i < 16; i++)
3913 ssh2_pkt_addbyte(ssh, (unsigned char) random_byte());
3914 /* List key exchange algorithms. */
3915 ssh2_pkt_addstring_start(ssh);
3916 for (i = 0; i < lenof(kex_algs); i++) {
3917 if (kex_algs[i] == &ssh_diffiehellman_gex &&
3918 (ssh->remote_bugs & BUG_SSH2_DH_GEX))
3919 continue;
3920 ssh2_pkt_addstring_str(ssh, kex_algs[i]->name);
3921 if (i < lenof(kex_algs) - 1)
3922 ssh2_pkt_addstring_str(ssh, ",");
3923 }
3924 /* List server host key algorithms. */
3925 ssh2_pkt_addstring_start(ssh);
3926 for (i = 0; i < lenof(hostkey_algs); i++) {
3927 ssh2_pkt_addstring_str(ssh, hostkey_algs[i]->name);
3928 if (i < lenof(hostkey_algs) - 1)
3929 ssh2_pkt_addstring_str(ssh, ",");
3930 }
3931 /* List client->server encryption algorithms. */
3932 ssh2_pkt_addstring_start(ssh);
3933 cipherstr_started = 0;
3934 for (i = 0; i < s->n_preferred_ciphers; i++) {
3935 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3936 if (!c) continue; /* warning flag */
3937 for (j = 0; j < c->nciphers; j++) {
3938 if (cipherstr_started)
3939 ssh2_pkt_addstring_str(ssh, ",");
3940 ssh2_pkt_addstring_str(ssh, c->list[j]->name);
3941 cipherstr_started = 1;
3942 }
3943 }
3944 /* List server->client encryption algorithms. */
3945 ssh2_pkt_addstring_start(ssh);
3946 cipherstr_started = 0;
3947 for (i = 0; i < s->n_preferred_ciphers; i++) {
3948 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3949 if (!c) continue; /* warning flag */
3950 for (j = 0; j < c->nciphers; j++) {
3951 if (cipherstr_started)
3952 ssh2_pkt_addstring_str(ssh, ",");
3953 ssh2_pkt_addstring_str(ssh, c->list[j]->name);
3954 cipherstr_started = 1;
3955 }
3956 }
3957 /* List client->server MAC algorithms. */
3958 ssh2_pkt_addstring_start(ssh);
3959 for (i = 0; i < s->nmacs; i++) {
3960 ssh2_pkt_addstring_str(ssh, s->maclist[i]->name);
3961 if (i < s->nmacs - 1)
3962 ssh2_pkt_addstring_str(ssh, ",");
3963 }
3964 /* List server->client MAC algorithms. */
3965 ssh2_pkt_addstring_start(ssh);
3966 for (i = 0; i < s->nmacs; i++) {
3967 ssh2_pkt_addstring_str(ssh, s->maclist[i]->name);
3968 if (i < s->nmacs - 1)
3969 ssh2_pkt_addstring_str(ssh, ",");
3970 }
3971 /* List client->server compression algorithms. */
3972 ssh2_pkt_addstring_start(ssh);
3973 for (i = 0; i < lenof(compressions) + 1; i++) {
3974 const struct ssh_compress *c =
3975 i == 0 ? s->preferred_comp : compressions[i - 1];
3976 ssh2_pkt_addstring_str(ssh, c->name);
3977 if (i < lenof(compressions))
3978 ssh2_pkt_addstring_str(ssh, ",");
3979 }
3980 /* List server->client compression algorithms. */
3981 ssh2_pkt_addstring_start(ssh);
3982 for (i = 0; i < lenof(compressions) + 1; i++) {
3983 const struct ssh_compress *c =
3984 i == 0 ? s->preferred_comp : compressions[i - 1];
3985 ssh2_pkt_addstring_str(ssh, c->name);
3986 if (i < lenof(compressions))
3987 ssh2_pkt_addstring_str(ssh, ",");
3988 }
3989 /* List client->server languages. Empty list. */
3990 ssh2_pkt_addstring_start(ssh);
3991 /* List server->client languages. Empty list. */
3992 ssh2_pkt_addstring_start(ssh);
3993 /* First KEX packet does _not_ follow, because we're not that brave. */
3994 ssh2_pkt_addbool(ssh, FALSE);
3995 /* Reserved. */
3996 ssh2_pkt_adduint32(ssh, 0);
3997 }
3998
3999 ssh->exhash = ssh->exhashbase;
4000 sha_string(&ssh->exhash, ssh->pktout.data + 5, ssh->pktout.length - 5);
4001
4002 ssh2_pkt_send(ssh);
4003
4004 if (!ispkt)
4005 crWaitUntil(ispkt);
4006 if (ssh->pktin.length > 5)
4007 sha_string(&ssh->exhash, ssh->pktin.data + 5, ssh->pktin.length - 5);
4008
4009 /*
4010 * Now examine the other side's KEXINIT to see what we're up
4011 * to.
4012 */
4013 {
4014 char *str;
4015 int i, j, len;
4016
4017 if (ssh->pktin.type != SSH2_MSG_KEXINIT) {
4018 bombout(("expected key exchange packet from server"));
4019 crStop(0);
4020 }
4021 ssh->kex = NULL;
4022 ssh->hostkey = NULL;
4023 s->cscipher_tobe = NULL;
4024 s->sccipher_tobe = NULL;
4025 s->csmac_tobe = NULL;
4026 s->scmac_tobe = NULL;
4027 s->cscomp_tobe = NULL;
4028 s->sccomp_tobe = NULL;
4029 ssh->pktin.savedpos += 16; /* skip garbage cookie */
4030 ssh2_pkt_getstring(ssh, &str, &len); /* key exchange algorithms */
4031 for (i = 0; i < lenof(kex_algs); i++) {
4032 if (kex_algs[i] == &ssh_diffiehellman_gex &&
4033 (ssh->remote_bugs & BUG_SSH2_DH_GEX))
4034 continue;
4035 if (in_commasep_string(kex_algs[i]->name, str, len)) {
4036 ssh->kex = kex_algs[i];
4037 break;
4038 }
4039 }
4040 ssh2_pkt_getstring(ssh, &str, &len); /* host key algorithms */
4041 for (i = 0; i < lenof(hostkey_algs); i++) {
4042 if (in_commasep_string(hostkey_algs[i]->name, str, len)) {
4043 ssh->hostkey = hostkey_algs[i];
4044 break;
4045 }
4046 }
4047 ssh2_pkt_getstring(ssh, &str, &len); /* client->server cipher */
4048 s->warn = 0;
4049 for (i = 0; i < s->n_preferred_ciphers; i++) {
4050 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
4051 if (!c) {
4052 s->warn = 1;
4053 } else {
4054 for (j = 0; j < c->nciphers; j++) {
4055 if (in_commasep_string(c->list[j]->name, str, len)) {
4056 s->cscipher_tobe = c->list[j];
4057 break;
4058 }
4059 }
4060 }
4061 if (s->cscipher_tobe) {
4062 if (s->warn)
4063 askcipher(ssh->frontend, s->cscipher_tobe->name, 1);
4064 break;
4065 }
4066 }
4067 if (!s->cscipher_tobe) {
4068 bombout(("Couldn't agree a client-to-server cipher (available: %s)",
4069 str ? str : "(null)"));
4070 crStop(0);
4071 }
4072
4073 ssh2_pkt_getstring(ssh, &str, &len); /* server->client cipher */
4074 s->warn = 0;
4075 for (i = 0; i < s->n_preferred_ciphers; i++) {
4076 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
4077 if (!c) {
4078 s->warn = 1;
4079 } else {
4080 for (j = 0; j < c->nciphers; j++) {
4081 if (in_commasep_string(c->list[j]->name, str, len)) {
4082 s->sccipher_tobe = c->list[j];
4083 break;
4084 }
4085 }
4086 }
4087 if (s->sccipher_tobe) {
4088 if (s->warn)
4089 askcipher(ssh->frontend, s->sccipher_tobe->name, 2);
4090 break;
4091 }
4092 }
4093 if (!s->sccipher_tobe) {
4094 bombout(("Couldn't agree a server-to-client cipher (available: %s)",
4095 str ? str : "(null)"));
4096 crStop(0);
4097 }
4098
4099 ssh2_pkt_getstring(ssh, &str, &len); /* client->server mac */
4100 for (i = 0; i < s->nmacs; i++) {
4101 if (in_commasep_string(s->maclist[i]->name, str, len)) {
4102 s->csmac_tobe = s->maclist[i];
4103 break;
4104 }
4105 }
4106 ssh2_pkt_getstring(ssh, &str, &len); /* server->client mac */
4107 for (i = 0; i < s->nmacs; i++) {
4108 if (in_commasep_string(s->maclist[i]->name, str, len)) {
4109 s->scmac_tobe = s->maclist[i];
4110 break;
4111 }
4112 }
4113 ssh2_pkt_getstring(ssh, &str, &len); /* client->server compression */
4114 for (i = 0; i < lenof(compressions) + 1; i++) {
4115 const struct ssh_compress *c =
4116 i == 0 ? s->preferred_comp : compressions[i - 1];
4117 if (in_commasep_string(c->name, str, len)) {
4118 s->cscomp_tobe = c;
4119 break;
4120 }
4121 }
4122 ssh2_pkt_getstring(ssh, &str, &len); /* server->client compression */
4123 for (i = 0; i < lenof(compressions) + 1; i++) {
4124 const struct ssh_compress *c =
4125 i == 0 ? s->preferred_comp : compressions[i - 1];
4126 if (in_commasep_string(c->name, str, len)) {
4127 s->sccomp_tobe = c;
4128 break;
4129 }
4130 }
4131 }
4132
4133 /*
4134 * Work out the number of bits of key we will need from the key
4135 * exchange. We start with the maximum key length of either
4136 * cipher...
4137 */
4138 {
4139 int csbits, scbits;
4140
4141 csbits = s->cscipher_tobe->keylen;
4142 scbits = s->sccipher_tobe->keylen;
4143 s->nbits = (csbits > scbits ? csbits : scbits);
4144 }
4145 /* The keys only have 160-bit entropy, since they're based on
4146 * a SHA-1 hash. So cap the key size at 160 bits. */
4147 if (s->nbits > 160)
4148 s->nbits = 160;
4149
4150 /*
4151 * If we're doing Diffie-Hellman group exchange, start by
4152 * requesting a group.
4153 */
4154 if (ssh->kex == &ssh_diffiehellman_gex) {
4155 logevent("Doing Diffie-Hellman group exchange");
4156 ssh->pkt_ctx |= SSH2_PKTCTX_DHGEX;
4157 /*
4158 * Work out how big a DH group we will need to allow that
4159 * much data.
4160 */
4161 s->pbits = 512 << ((s->nbits - 1) / 64);
4162 ssh2_pkt_init(ssh, SSH2_MSG_KEX_DH_GEX_REQUEST);
4163 ssh2_pkt_adduint32(ssh, s->pbits);
4164 ssh2_pkt_send(ssh);
4165
4166 crWaitUntil(ispkt);
4167 if (ssh->pktin.type != SSH2_MSG_KEX_DH_GEX_GROUP) {
4168 bombout(("expected key exchange group packet from server"));
4169 crStop(0);
4170 }
4171 s->p = ssh2_pkt_getmp(ssh);
4172 s->g = ssh2_pkt_getmp(ssh);
4173 ssh->kex_ctx = dh_setup_group(s->p, s->g);
4174 s->kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT;
4175 s->kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY;
4176 } else {
4177 ssh->pkt_ctx |= SSH2_PKTCTX_DHGROUP1;
4178 ssh->kex_ctx = dh_setup_group1();
4179 s->kex_init_value = SSH2_MSG_KEXDH_INIT;
4180 s->kex_reply_value = SSH2_MSG_KEXDH_REPLY;
4181 }
4182
4183 logevent("Doing Diffie-Hellman key exchange");
4184 /*
4185 * Now generate and send e for Diffie-Hellman.
4186 */
4187 s->e = dh_create_e(ssh->kex_ctx, s->nbits * 2);
4188 ssh2_pkt_init(ssh, s->kex_init_value);
4189 ssh2_pkt_addmp(ssh, s->e);
4190 ssh2_pkt_send(ssh);
4191
4192 crWaitUntil(ispkt);
4193 if (ssh->pktin.type != s->kex_reply_value) {
4194 bombout(("expected key exchange reply packet from server"));
4195 crStop(0);
4196 }
4197 ssh2_pkt_getstring(ssh, &s->hostkeydata, &s->hostkeylen);
4198 s->f = ssh2_pkt_getmp(ssh);
4199 ssh2_pkt_getstring(ssh, &s->sigdata, &s->siglen);
4200
4201 s->K = dh_find_K(ssh->kex_ctx, s->f);
4202
4203 sha_string(&ssh->exhash, s->hostkeydata, s->hostkeylen);
4204 if (ssh->kex == &ssh_diffiehellman_gex) {
4205 sha_uint32(&ssh->exhash, s->pbits);
4206 sha_mpint(&ssh->exhash, s->p);
4207 sha_mpint(&ssh->exhash, s->g);
4208 }
4209 sha_mpint(&ssh->exhash, s->e);
4210 sha_mpint(&ssh->exhash, s->f);
4211 sha_mpint(&ssh->exhash, s->K);
4212 SHA_Final(&ssh->exhash, s->exchange_hash);
4213
4214 dh_cleanup(ssh->kex_ctx);
4215 ssh->kex_ctx = NULL;
4216
4217 #if 0
4218 debug(("Exchange hash is:\n"));
4219 dmemdump(s->exchange_hash, 20);
4220 #endif
4221
4222 s->hkey = ssh->hostkey->newkey(s->hostkeydata, s->hostkeylen);
4223 if (!s->hkey ||
4224 !ssh->hostkey->verifysig(s->hkey, s->sigdata, s->siglen,
4225 (char *)s->exchange_hash, 20)) {
4226 bombout(("Server's host key did not match the signature supplied"));
4227 crStop(0);
4228 }
4229
4230 /*
4231 * Authenticate remote host: verify host key. (We've already
4232 * checked the signature of the exchange hash.)
4233 */
4234 s->keystr = ssh->hostkey->fmtkey(s->hkey);
4235 s->fingerprint = ssh->hostkey->fingerprint(s->hkey);
4236 verify_ssh_host_key(ssh->frontend,
4237 ssh->savedhost, ssh->savedport, ssh->hostkey->keytype,
4238 s->keystr, s->fingerprint);
4239 if (s->first_kex) { /* don't bother logging this in rekeys */
4240 logevent("Host key fingerprint is:");
4241 logevent(s->fingerprint);
4242 }
4243 sfree(s->fingerprint);
4244 sfree(s->keystr);
4245 ssh->hostkey->freekey(s->hkey);
4246
4247 /*
4248 * Send SSH2_MSG_NEWKEYS.
4249 */
4250 ssh2_pkt_init(ssh, SSH2_MSG_NEWKEYS);
4251 ssh2_pkt_send(ssh);
4252
4253 /*
4254 * Expect SSH2_MSG_NEWKEYS from server.
4255 */
4256 crWaitUntil(ispkt);
4257 if (ssh->pktin.type != SSH2_MSG_NEWKEYS) {
4258 bombout(("expected new-keys packet from server"));
4259 crStop(0);
4260 }
4261
4262 /*
4263 * Create and initialise session keys.
4264 */
4265 if (ssh->cs_cipher_ctx)
4266 ssh->cscipher->free_context(ssh->cs_cipher_ctx);
4267 ssh->cscipher = s->cscipher_tobe;
4268 ssh->cs_cipher_ctx = ssh->cscipher->make_context();
4269
4270 if (ssh->sc_cipher_ctx)
4271 ssh->sccipher->free_context(ssh->sc_cipher_ctx);
4272 ssh->sccipher = s->sccipher_tobe;
4273 ssh->sc_cipher_ctx = ssh->sccipher->make_context();
4274
4275 if (ssh->cs_mac_ctx)
4276 ssh->csmac->free_context(ssh->cs_mac_ctx);
4277 ssh->csmac = s->csmac_tobe;
4278 ssh->cs_mac_ctx = ssh->csmac->make_context();
4279
4280 if (ssh->sc_mac_ctx)
4281 ssh->scmac->free_context(ssh->sc_mac_ctx);
4282 ssh->scmac = s->scmac_tobe;
4283 ssh->sc_mac_ctx = ssh->scmac->make_context();
4284
4285 if (ssh->cs_comp_ctx)
4286 ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
4287 ssh->cscomp = s->cscomp_tobe;
4288 ssh->cs_comp_ctx = ssh->cscomp->compress_init();
4289
4290 if (ssh->sc_comp_ctx)
4291 ssh->sccomp->decompress_cleanup(ssh->sc_comp_ctx);
4292 ssh->sccomp = s->sccomp_tobe;
4293 ssh->sc_comp_ctx = ssh->sccomp->decompress_init();
4294
4295 /*
4296 * Set IVs after keys. Here we use the exchange hash from the
4297 * _first_ key exchange.
4298 */
4299 {
4300 unsigned char keyspace[40];
4301 if (s->first_kex)
4302 memcpy(ssh->v2_session_id, s->exchange_hash,
4303 sizeof(s->exchange_hash));
4304 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'C',keyspace);
4305 ssh->cscipher->setkey(ssh->cs_cipher_ctx, keyspace);
4306 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'D',keyspace);
4307 ssh->sccipher->setkey(ssh->sc_cipher_ctx, keyspace);
4308 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'A',keyspace);
4309 ssh->cscipher->setiv(ssh->cs_cipher_ctx, keyspace);
4310 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'B',keyspace);
4311 ssh->sccipher->setiv(ssh->sc_cipher_ctx, keyspace);
4312 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'E',keyspace);
4313 ssh->csmac->setkey(ssh->cs_mac_ctx, keyspace);
4314 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'F',keyspace);
4315 ssh->scmac->setkey(ssh->sc_mac_ctx, keyspace);
4316 }
4317 logeventf(ssh, "Initialised %.200s client->server encryption",
4318 ssh->cscipher->text_name);
4319 logeventf(ssh, "Initialised %.200s server->client encryption",
4320 ssh->sccipher->text_name);
4321 if (ssh->cscomp->text_name)
4322 logeventf(ssh, "Initialised %s compression",
4323 ssh->cscomp->text_name);
4324 if (ssh->sccomp->text_name)
4325 logeventf(ssh, "Initialised %s decompression",
4326 ssh->sccomp->text_name);
4327
4328 /*
4329 * If this is the first key exchange phase, we must pass the
4330 * SSH2_MSG_NEWKEYS packet to the next layer, not because it
4331 * wants to see it but because it will need time to initialise
4332 * itself before it sees an actual packet. In subsequent key
4333 * exchange phases, we don't pass SSH2_MSG_NEWKEYS on, because
4334 * it would only confuse the layer above.
4335 */
4336 if (!s->first_kex) {
4337 crReturn(0);
4338 }
4339 s->first_kex = 0;
4340
4341 /*
4342 * Now we're encrypting. Begin returning 1 to the protocol main
4343 * function so that other things can run on top of the
4344 * transport. If we ever see a KEXINIT, we must go back to the
4345 * start.
4346 */
4347 while (!(ispkt && ssh->pktin.type == SSH2_MSG_KEXINIT)) {
4348 crReturn(1);
4349 }
4350 logevent("Server initiated key re-exchange");
4351 goto begin_key_exchange;
4352
4353 crFinish(1);
4354 }
4355
4356 /*
4357 * Add data to an SSH2 channel output buffer.
4358 */
4359 static void ssh2_add_channel_data(struct ssh_channel *c, char *buf,
4360 int len)
4361 {
4362 bufchain_add(&c->v.v2.outbuffer, buf, len);
4363 }
4364
4365 /*
4366 * Attempt to send data on an SSH2 channel.
4367 */
4368 static int ssh2_try_send(struct ssh_channel *c)
4369 {
4370 Ssh ssh = c->ssh;
4371
4372 while (c->v.v2.remwindow > 0 && bufchain_size(&c->v.v2.outbuffer) > 0) {
4373 int len;
4374 void *data;
4375 bufchain_prefix(&c->v.v2.outbuffer, &data, &len);
4376 if ((unsigned)len > c->v.v2.remwindow)
4377 len = c->v.v2.remwindow;
4378 if ((unsigned)len > c->v.v2.remmaxpkt)
4379 len = c->v.v2.remmaxpkt;
4380 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_DATA);
4381 ssh2_pkt_adduint32(ssh, c->remoteid);
4382 ssh2_pkt_addstring_start(ssh);
4383 ssh2_pkt_addstring_data(ssh, data, len);
4384 ssh2_pkt_send(ssh);
4385 bufchain_consume(&c->v.v2.outbuffer, len);
4386 c->v.v2.remwindow -= len;
4387 }
4388
4389 /*
4390 * After having sent as much data as we can, return the amount
4391 * still buffered.
4392 */
4393 return bufchain_size(&c->v.v2.outbuffer);
4394 }
4395
4396 /*
4397 * Potentially enlarge the window on an SSH2 channel.
4398 */
4399 static void ssh2_set_window(struct ssh_channel *c, unsigned newwin)
4400 {
4401 Ssh ssh = c->ssh;
4402
4403 /*
4404 * Never send WINDOW_ADJUST for a channel that the remote side
4405 * already thinks it's closed; there's no point, since it won't
4406 * be sending any more data anyway.
4407 */
4408 if (c->closes != 0)
4409 return;
4410
4411 if (newwin > c->v.v2.locwindow) {
4412 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST);
4413 ssh2_pkt_adduint32(ssh, c->remoteid);
4414 ssh2_pkt_adduint32(ssh, newwin - c->v.v2.locwindow);
4415 ssh2_pkt_send(ssh);
4416 c->v.v2.locwindow = newwin;
4417 }
4418 }
4419
4420 /*
4421 * Handle the SSH2 userauth and connection layers.
4422 */
4423 static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
4424 {
4425 struct do_ssh2_authconn_state {
4426 enum {
4427 AUTH_INVALID, AUTH_PUBLICKEY_AGENT, AUTH_PUBLICKEY_FILE,
4428 AUTH_PASSWORD,
4429 AUTH_KEYBOARD_INTERACTIVE
4430 } method;
4431 enum {
4432 AUTH_TYPE_NONE,
4433 AUTH_TYPE_PUBLICKEY,
4434 AUTH_TYPE_PUBLICKEY_OFFER_LOUD,
4435 AUTH_TYPE_PUBLICKEY_OFFER_QUIET,
4436 AUTH_TYPE_PASSWORD,
4437 AUTH_TYPE_KEYBOARD_INTERACTIVE,
4438 AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET
4439 } type;
4440 int gotit, need_pw, can_pubkey, can_passwd, can_keyb_inter;
4441 int tried_pubkey_config, tried_agent, tried_keyb_inter;
4442 int kbd_inter_running;
4443 int we_are_in;
4444 int num_prompts, curr_prompt, echo;
4445 char username[100];
4446 int got_username;
4447 char pwprompt[200];
4448 char password[100];
4449 void *publickey_blob;
4450 int publickey_bloblen;
4451 unsigned char request[5], *response, *p;
4452 int responselen;
4453 int keyi, nkeys;
4454 int authed;
4455 char *pkblob, *alg, *commentp;
4456 int pklen, alglen, commentlen;
4457 int siglen, retlen, len;
4458 char *q, *agentreq, *ret;
4459 int try_send;
4460 };
4461 crState(do_ssh2_authconn_state);
4462
4463 crBegin(ssh->do_ssh2_authconn_crstate);
4464
4465 /*
4466 * Request userauth protocol, and await a response to it.
4467 */
4468 ssh2_pkt_init(ssh, SSH2_MSG_SERVICE_REQUEST);
4469 ssh2_pkt_addstring(ssh, "ssh-userauth");
4470 ssh2_pkt_send(ssh);
4471 crWaitUntilV(ispkt);
4472 if (ssh->pktin.type != SSH2_MSG_SERVICE_ACCEPT) {
4473 bombout(("Server refused user authentication protocol"));
4474 crStopV;
4475 }
4476
4477 /*
4478 * We repeat this whole loop, including the username prompt,
4479 * until we manage a successful authentication. If the user
4480 * types the wrong _password_, they can be sent back to the
4481 * beginning to try another username, if this is configured on.
4482 * (If they specify a username in the config, they are never
4483 * asked, even if they do give a wrong password.)
4484 *
4485 * I think this best serves the needs of
4486 *
4487 * - the people who have no configuration, no keys, and just
4488 * want to try repeated (username,password) pairs until they
4489 * type both correctly
4490 *
4491 * - people who have keys and configuration but occasionally
4492 * need to fall back to passwords
4493 *
4494 * - people with a key held in Pageant, who might not have
4495 * logged in to a particular machine before; so they want to
4496 * type a username, and then _either_ their key will be
4497 * accepted, _or_ they will type a password. If they mistype
4498 * the username they will want to be able to get back and
4499 * retype it!
4500 */
4501 s->username[0] = '\0';
4502 s->got_username = FALSE;
4503 do {
4504 /*
4505 * Get a username.
4506 */
4507 if (s->got_username && !ssh->cfg.change_username) {
4508 /*
4509 * We got a username last time round this loop, and
4510 * with change_username turned off we don't try to get
4511 * it again.
4512 */
4513 } else if ((flags & FLAG_INTERACTIVE) && !*ssh->cfg.username) {
4514 if (ssh_get_line && !ssh_getline_pw_only) {
4515 if (!ssh_get_line("login as: ",
4516 s->username, sizeof(s->username), FALSE)) {
4517 /*
4518 * get_line failed to get a username.
4519 * Terminate.
4520 */
4521 logevent("No username provided. Abandoning session.");
4522 ssh_closing((Plug)ssh, NULL, 0, 0);
4523 crStopV;
4524 }
4525 } else {
4526 int ret; /* need not be saved across crReturn */
4527 c_write_str(ssh, "login as: ");
4528 ssh->send_ok = 1;
4529 setup_userpass_input(ssh, s->username, sizeof(s->username), 1);
4530 do {
4531 crWaitUntilV(!ispkt);
4532 ret = process_userpass_input(ssh, in, inlen);
4533 } while (ret == 0);
4534 if (ret < 0)
4535 cleanup_exit(0);
4536 c_write_str(ssh, "\r\n");
4537 }
4538 s->username[strcspn(s->username, "\n\r")] = '\0';
4539 } else {
4540 char *stuff;
4541 strncpy(s->username, ssh->cfg.username, sizeof(s->username));
4542 s->username[sizeof(s->username)-1] = '\0';
4543 if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
4544 stuff = dupprintf("Using username \"%s\".\r\n", s->username);
4545 c_write_str(ssh, stuff);
4546 sfree(stuff);
4547 }
4548 }
4549 s->got_username = TRUE;
4550
4551 /*
4552 * Send an authentication request using method "none": (a)
4553 * just in case it succeeds, and (b) so that we know what
4554 * authentication methods we can usefully try next.
4555 */
4556 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4557
4558 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4559 ssh2_pkt_addstring(ssh, s->username);
4560 ssh2_pkt_addstring(ssh, "ssh-connection");/* service requested */
4561 ssh2_pkt_addstring(ssh, "none"); /* method */
4562 ssh2_pkt_send(ssh);
4563 s->type = AUTH_TYPE_NONE;
4564 s->gotit = FALSE;
4565 s->we_are_in = FALSE;
4566
4567 s->tried_pubkey_config = FALSE;
4568 s->tried_agent = FALSE;
4569 s->tried_keyb_inter = FALSE;
4570 s->kbd_inter_running = FALSE;
4571 /* Load the pub half of ssh->cfg.keyfile so we notice if it's in Pageant */
4572 if (!filename_is_null(ssh->cfg.keyfile)) {
4573 int keytype;
4574 logeventf(ssh, "Reading private key file \"%.150s\"",
4575 filename_to_str(&ssh->cfg.keyfile));
4576 keytype = key_type(&ssh->cfg.keyfile);
4577 if (keytype == SSH_KEYTYPE_SSH2) {
4578 s->publickey_blob =
4579 ssh2_userkey_loadpub(&ssh->cfg.keyfile, NULL,
4580 &s->publickey_bloblen);
4581 } else {
4582 char *msgbuf;
4583 logeventf(ssh, "Unable to use this key file (%s)",
4584 key_type_to_str(keytype));
4585 msgbuf = dupprintf("Unable to use key file \"%.150s\""
4586 " (%s)\r\n",
4587 filename_to_str(&ssh->cfg.keyfile),
4588 key_type_to_str(keytype));
4589 c_write_str(ssh, msgbuf);
4590 sfree(msgbuf);
4591 s->publickey_blob = NULL;
4592 }
4593 } else
4594 s->publickey_blob = NULL;
4595
4596 while (1) {
4597 /*
4598 * Wait for the result of the last authentication request.
4599 */
4600 if (!s->gotit)
4601 crWaitUntilV(ispkt);
4602 while (ssh->pktin.type == SSH2_MSG_USERAUTH_BANNER) {
4603 char *banner;
4604 int size;
4605 /*
4606 * Don't show the banner if we're operating in
4607 * non-verbose non-interactive mode. (It's probably
4608 * a script, which means nobody will read the
4609 * banner _anyway_, and moreover the printing of
4610 * the banner will screw up processing on the
4611 * output of (say) plink.)
4612 */
4613 if (flags & (FLAG_VERBOSE | FLAG_INTERACTIVE)) {
4614 ssh2_pkt_getstring(ssh, &banner, &size);
4615 if (banner)
4616 c_write_untrusted(ssh, banner, size);
4617 }
4618 crWaitUntilV(ispkt);
4619 }
4620 if (ssh->pktin.type == SSH2_MSG_USERAUTH_SUCCESS) {
4621 logevent("Access granted");
4622 s->we_are_in = TRUE;
4623 break;
4624 }
4625
4626 if (s->kbd_inter_running &&
4627 ssh->pktin.type == SSH2_MSG_USERAUTH_INFO_REQUEST) {
4628 /*
4629 * This is either a further set-of-prompts packet
4630 * in keyboard-interactive authentication, or it's
4631 * the same one and we came back here with `gotit'
4632 * set. In the former case, we must reset the
4633 * curr_prompt variable.
4634 */
4635 if (!s->gotit)
4636 s->curr_prompt = 0;
4637 } else if (ssh->pktin.type != SSH2_MSG_USERAUTH_FAILURE) {
4638 bombout(("Strange packet received during authentication: type %d",
4639 ssh->pktin.type));
4640 crStopV;
4641 }
4642
4643 s->gotit = FALSE;
4644
4645 /*
4646 * OK, we're now sitting on a USERAUTH_FAILURE message, so
4647 * we can look at the string in it and know what we can
4648 * helpfully try next.
4649 */
4650 if (ssh->pktin.type == SSH2_MSG_USERAUTH_FAILURE) {
4651 char *methods;
4652 int methlen;
4653 ssh2_pkt_getstring(ssh, &methods, &methlen);
4654 s->kbd_inter_running = FALSE;
4655 if (!ssh2_pkt_getbool(ssh)) {
4656 /*
4657 * We have received an unequivocal Access
4658 * Denied. This can translate to a variety of
4659 * messages:
4660 *
4661 * - if we'd just tried "none" authentication,
4662 * it's not worth printing anything at all
4663 *
4664 * - if we'd just tried a public key _offer_,
4665 * the message should be "Server refused our
4666 * key" (or no message at all if the key
4667 * came from Pageant)
4668 *
4669 * - if we'd just tried anything else, the
4670 * message really should be "Access denied".
4671 *
4672 * Additionally, if we'd just tried password
4673 * authentication, we should break out of this
4674 * whole loop so as to go back to the username
4675 * prompt.
4676 */
4677 if (s->type == AUTH_TYPE_NONE) {
4678 /* do nothing */
4679 } else if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD ||
4680 s->type == AUTH_TYPE_PUBLICKEY_OFFER_QUIET) {
4681 if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD)
4682 c_write_str(ssh, "Server refused our key\r\n");
4683 logevent("Server refused public key");
4684 } else if (s->type==AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET) {
4685 /* server declined keyboard-interactive; ignore */
4686 } else {
4687 c_write_str(ssh, "Access denied\r\n");
4688 logevent("Access denied");
4689 if (s->type == AUTH_TYPE_PASSWORD) {
4690 s->we_are_in = FALSE;
4691 break;
4692 }
4693 }
4694 } else {
4695 c_write_str(ssh, "Further authentication required\r\n");
4696 logevent("Further authentication required");
4697 }
4698
4699 s->can_pubkey =
4700 in_commasep_string("publickey", methods, methlen);
4701 s->can_passwd =
4702 in_commasep_string("password", methods, methlen);
4703 s->can_keyb_inter = ssh->cfg.try_ki_auth &&
4704 in_commasep_string("keyboard-interactive", methods, methlen);
4705 }
4706
4707 s->method = 0;
4708 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4709
4710 /*
4711 * Most password/passphrase prompts will be
4712 * non-echoing, so we set this to 0 by default.
4713 * Exception is that some keyboard-interactive prompts
4714 * can be echoing, in which case we'll set this to 1.
4715 */
4716 s->echo = 0;
4717
4718 if (!s->method && s->can_pubkey &&
4719 agent_exists() && !s->tried_agent) {
4720 /*
4721 * Attempt public-key authentication using Pageant.
4722 */
4723 void *r;
4724 s->authed = FALSE;
4725
4726 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4727 ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
4728
4729 s->tried_agent = TRUE;
4730
4731 logevent("Pageant is running. Requesting keys.");
4732
4733 /* Request the keys held by the agent. */
4734 PUT_32BIT(s->request, 1);
4735 s->request[4] = SSH2_AGENTC_REQUEST_IDENTITIES;
4736 if (!agent_query(s->request, 5, &r, &s->responselen,
4737 ssh_agent_callback, ssh)) {
4738 do {
4739 crReturnV;
4740 if (ispkt) {
4741 bombout(("Unexpected data from server while"
4742 " waiting for agent response"));
4743 crStopV;
4744 }
4745 } while (ispkt || inlen > 0);
4746 r = ssh->agent_response;
4747 s->responselen = ssh->agent_response_len;
4748 }
4749 s->response = (unsigned char *) r;
4750 if (s->response && s->responselen >= 5 &&
4751 s->response[4] == SSH2_AGENT_IDENTITIES_ANSWER) {
4752 s->p = s->response + 5;
4753 s->nkeys = GET_32BIT(s->p);
4754 s->p += 4;
4755 {
4756 char buf[64];
4757 sprintf(buf, "Pageant has %d SSH2 keys", s->nkeys);
4758 logevent(buf);
4759 }
4760 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
4761 void *vret;
4762
4763 {
4764 char buf[64];
4765 sprintf(buf, "Trying Pageant key #%d", s->keyi);
4766 logevent(buf);
4767 }
4768 s->pklen = GET_32BIT(s->p);
4769 s->p += 4;
4770 if (s->publickey_blob &&
4771 s->pklen == s->publickey_bloblen &&
4772 !memcmp(s->p, s->publickey_blob,
4773 s->publickey_bloblen)) {
4774 logevent("This key matches configured key file");
4775 s->tried_pubkey_config = 1;
4776 }
4777 s->pkblob = (char *)s->p;
4778 s->p += s->pklen;
4779 s->alglen = GET_32BIT(s->pkblob);
4780 s->alg = s->pkblob + 4;
4781 s->commentlen = GET_32BIT(s->p);
4782 s->p += 4;
4783 s->commentp = (char *)s->p;
4784 s->p += s->commentlen;
4785 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4786 ssh2_pkt_addstring(ssh, s->username);
4787 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4788 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4789 ssh2_pkt_addbool(ssh, FALSE); /* no signature included */
4790 ssh2_pkt_addstring_start(ssh);
4791 ssh2_pkt_addstring_data(ssh, s->alg, s->alglen);
4792 ssh2_pkt_addstring_start(ssh);
4793 ssh2_pkt_addstring_data(ssh, s->pkblob, s->pklen);
4794 ssh2_pkt_send(ssh);
4795
4796 crWaitUntilV(ispkt);
4797 if (ssh->pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
4798 logevent("Key refused");
4799 continue;
4800 }
4801
4802 if (flags & FLAG_VERBOSE) {
4803 c_write_str(ssh, "Authenticating with "
4804 "public key \"");
4805 c_write(ssh, s->commentp, s->commentlen);
4806 c_write_str(ssh, "\" from agent\r\n");
4807 }
4808
4809 /*
4810 * Server is willing to accept the key.
4811 * Construct a SIGN_REQUEST.
4812 */
4813 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4814 ssh2_pkt_addstring(ssh, s->username);
4815 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4816 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4817 ssh2_pkt_addbool(ssh, TRUE);
4818 ssh2_pkt_addstring_start(ssh);
4819 ssh2_pkt_addstring_data(ssh, s->alg, s->alglen);
4820 ssh2_pkt_addstring_start(ssh);
4821 ssh2_pkt_addstring_data(ssh, s->pkblob, s->pklen);
4822
4823 s->siglen = ssh->pktout.length - 5 + 4 + 20;
4824 if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
4825 s->siglen -= 4;
4826 s->len = 1; /* message type */
4827 s->len += 4 + s->pklen; /* key blob */
4828 s->len += 4 + s->siglen; /* data to sign */
4829 s->len += 4; /* flags */
4830 s->agentreq = snewn(4 + s->len, char);
4831 PUT_32BIT(s->agentreq, s->len);
4832 s->q = s->agentreq + 4;
4833 *s->q++ = SSH2_AGENTC_SIGN_REQUEST;
4834 PUT_32BIT(s->q, s->pklen);
4835 s->q += 4;
4836 memcpy(s->q, s->pkblob, s->pklen);
4837 s->q += s->pklen;
4838 PUT_32BIT(s->q, s->siglen);
4839 s->q += 4;
4840 /* Now the data to be signed... */
4841 if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
4842 PUT_32BIT(s->q, 20);
4843 s->q += 4;
4844 }
4845 memcpy(s->q, ssh->v2_session_id, 20);
4846 s->q += 20;
4847 memcpy(s->q, ssh->pktout.data + 5,
4848 ssh->pktout.length - 5);
4849 s->q += ssh->pktout.length - 5;
4850 /* And finally the (zero) flags word. */
4851 PUT_32BIT(s->q, 0);
4852 if (!agent_query(s->agentreq, s->len + 4,
4853 &vret, &s->retlen,
4854 ssh_agent_callback, ssh)) {
4855 do {
4856 crReturnV;
4857 if (ispkt) {
4858 bombout(("Unexpected data from server"
4859 " while waiting for agent"
4860 " response"));
4861 crStopV;
4862 }
4863 } while (ispkt || inlen > 0);
4864 vret = ssh->agent_response;
4865 s->retlen = ssh->agent_response_len;
4866 }
4867 s->ret = vret;
4868 sfree(s->agentreq);
4869 if (s->ret) {
4870 if (s->ret[4] == SSH2_AGENT_SIGN_RESPONSE) {
4871 logevent("Sending Pageant's response");
4872 ssh2_add_sigblob(ssh, s->pkblob, s->pklen,
4873 s->ret + 9,
4874 GET_32BIT(s->ret + 5));
4875 ssh2_pkt_send(ssh);
4876 s->authed = TRUE;
4877 break;
4878 } else {
4879 logevent
4880 ("Pageant failed to answer challenge");
4881 sfree(s->ret);
4882 }
4883 }
4884 }
4885 if (s->authed)
4886 continue;
4887 }
4888 }
4889
4890 if (!s->method && s->can_pubkey && s->publickey_blob
4891 && !s->tried_pubkey_config) {
4892 unsigned char *pub_blob;
4893 char *algorithm, *comment;
4894 int pub_blob_len;
4895
4896 s->tried_pubkey_config = TRUE;
4897
4898 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4899 ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
4900
4901 /*
4902 * Try the public key supplied in the configuration.
4903 *
4904 * First, offer the public blob to see if the server is
4905 * willing to accept it.
4906 */
4907 pub_blob =
4908 (unsigned char *)ssh2_userkey_loadpub(&ssh->cfg.keyfile,
4909 &algorithm,
4910 &pub_blob_len);
4911 if (pub_blob) {
4912 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4913 ssh2_pkt_addstring(ssh, s->username);
4914 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4915 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4916 ssh2_pkt_addbool(ssh, FALSE); /* no signature included */
4917 ssh2_pkt_addstring(ssh, algorithm);
4918 ssh2_pkt_addstring_start(ssh);
4919 ssh2_pkt_addstring_data(ssh, (char *)pub_blob,
4920 pub_blob_len);
4921 ssh2_pkt_send(ssh);
4922 logevent("Offered public key"); /* FIXME */
4923
4924 crWaitUntilV(ispkt);
4925 if (ssh->pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
4926 s->gotit = TRUE;
4927 s->type = AUTH_TYPE_PUBLICKEY_OFFER_LOUD;
4928 continue; /* key refused; give up on it */
4929 }
4930
4931 logevent("Offer of public key accepted");
4932 /*
4933 * Actually attempt a serious authentication using
4934 * the key.
4935 */
4936 if (ssh2_userkey_encrypted(&ssh->cfg.keyfile, &comment)) {
4937 sprintf(s->pwprompt,
4938 "Passphrase for key \"%.100s\": ",
4939 comment);
4940 s->need_pw = TRUE;
4941 } else {
4942 s->need_pw = FALSE;
4943 }
4944 c_write_str(ssh, "Authenticating with public key \"");
4945 c_write_str(ssh, comment);
4946 c_write_str(ssh, "\"\r\n");
4947 s->method = AUTH_PUBLICKEY_FILE;
4948 }
4949 }
4950
4951 if (!s->method && s->can_keyb_inter && !s->tried_keyb_inter) {
4952 s->method = AUTH_KEYBOARD_INTERACTIVE;
4953 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
4954 s->tried_keyb_inter = TRUE;
4955
4956 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4957 ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;
4958
4959 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4960 ssh2_pkt_addstring(ssh, s->username);
4961 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4962 ssh2_pkt_addstring(ssh, "keyboard-interactive"); /* method */
4963 ssh2_pkt_addstring(ssh, ""); /* lang */
4964 ssh2_pkt_addstring(ssh, "");
4965 ssh2_pkt_send(ssh);
4966
4967 crWaitUntilV(ispkt);
4968 if (ssh->pktin.type != SSH2_MSG_USERAUTH_INFO_REQUEST) {
4969 if (ssh->pktin.type == SSH2_MSG_USERAUTH_FAILURE)
4970 s->gotit = TRUE;
4971 logevent("Keyboard-interactive authentication refused");
4972 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET;
4973 continue;
4974 }
4975
4976 s->kbd_inter_running = TRUE;
4977 s->curr_prompt = 0;
4978 }
4979
4980 if (s->kbd_inter_running) {
4981 s->method = AUTH_KEYBOARD_INTERACTIVE;
4982 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
4983 s->tried_keyb_inter = TRUE;
4984
4985 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4986 ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;
4987
4988 if (s->curr_prompt == 0) {
4989 /*
4990 * We've got a fresh USERAUTH_INFO_REQUEST.
4991 * Display header data, and start going through
4992 * the prompts.
4993 */
4994 char *name, *inst, *lang;
4995 int name_len, inst_len, lang_len;
4996
4997 ssh2_pkt_getstring(ssh, &name, &name_len);
4998 ssh2_pkt_getstring(ssh, &inst, &inst_len);
4999 ssh2_pkt_getstring(ssh, &lang, &lang_len);
5000 if (name_len > 0) {
5001 c_write_untrusted(ssh, name, name_len);
5002 c_write_str(ssh, "\r\n");
5003 }
5004 if (inst_len > 0) {
5005 c_write_untrusted(ssh, inst, inst_len);
5006 c_write_str(ssh, "\r\n");
5007 }
5008 s->num_prompts = ssh2_pkt_getuint32(ssh);
5009 }
5010
5011 /*
5012 * If there are prompts remaining in the packet,
5013 * display one and get a response.
5014 */
5015 if (s->curr_prompt < s->num_prompts) {
5016 char *prompt;
5017 int prompt_len;
5018
5019 ssh2_pkt_getstring(ssh, &prompt, &prompt_len);
5020 if (prompt_len > 0) {
5021 strncpy(s->pwprompt, prompt, sizeof(s->pwprompt));
5022 s->pwprompt[prompt_len < sizeof(s->pwprompt) ?
5023 prompt_len : sizeof(s->pwprompt)-1] = '\0';
5024 } else {
5025 strcpy(s->pwprompt,
5026 "<server failed to send prompt>: ");
5027 }
5028 s->echo = ssh2_pkt_getbool(ssh);
5029 s->need_pw = TRUE;
5030 } else
5031 s->need_pw = FALSE;
5032 }
5033
5034 if (!s->method && s->can_passwd) {
5035 s->method = AUTH_PASSWORD;
5036 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
5037 ssh->pkt_ctx |= SSH2_PKTCTX_PASSWORD;
5038 sprintf(s->pwprompt, "%.90s@%.90s's password: ", s->username,
5039 ssh->savedhost);
5040 s->need_pw = TRUE;
5041 }
5042
5043 if (s->need_pw) {
5044 if (ssh_get_line) {
5045 if (!ssh_get_line(s->pwprompt, s->password,
5046 sizeof(s->password), TRUE)) {
5047 /*
5048 * get_line failed to get a password (for
5049 * example because one was supplied on the
5050 * command line which has already failed to
5051 * work). Terminate.
5052 */
5053 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5054 ssh2_pkt_adduint32(ssh,SSH2_DISCONNECT_BY_APPLICATION);
5055 ssh2_pkt_addstring(ssh, "No more passwords available"
5056 " to try");
5057 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5058 ssh2_pkt_send(ssh);
5059 logevent("Unable to authenticate");
5060 connection_fatal(ssh->frontend,
5061 "Unable to authenticate");
5062 ssh_closing((Plug)ssh, NULL, 0, 0);
5063 crStopV;
5064 }
5065 } else {
5066 int ret; /* need not be saved across crReturn */
5067 c_write_untrusted(ssh, s->pwprompt, strlen(s->pwprompt));
5068 ssh->send_ok = 1;
5069
5070 setup_userpass_input(ssh, s->password,
5071 sizeof(s->password), s->echo);
5072 do {
5073 crWaitUntilV(!ispkt);
5074 ret = process_userpass_input(ssh, in, inlen);
5075 } while (ret == 0);
5076 if (ret < 0)
5077 cleanup_exit(0);
5078 c_write_str(ssh, "\r\n");
5079 }
5080 }
5081
5082 if (s->method == AUTH_PUBLICKEY_FILE) {
5083 /*
5084 * We have our passphrase. Now try the actual authentication.
5085 */
5086 struct ssh2_userkey *key;
5087
5088 key = ssh2_load_userkey(&ssh->cfg.keyfile, s->password);
5089 if (key == SSH2_WRONG_PASSPHRASE || key == NULL) {
5090 if (key == SSH2_WRONG_PASSPHRASE) {
5091 c_write_str(ssh, "Wrong passphrase\r\n");
5092 s->tried_pubkey_config = FALSE;
5093 } else {
5094 c_write_str(ssh, "Unable to load private key\r\n");
5095 s->tried_pubkey_config = TRUE;
5096 }
5097 /* Send a spurious AUTH_NONE to return to the top. */
5098 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
5099 ssh2_pkt_addstring(ssh, s->username);
5100 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
5101 ssh2_pkt_addstring(ssh, "none"); /* method */
5102 ssh2_pkt_send(ssh);
5103 s->type = AUTH_TYPE_NONE;
5104 } else {
5105 unsigned char *pkblob, *sigblob, *sigdata;
5106 int pkblob_len, sigblob_len, sigdata_len;
5107 int p;
5108
5109 /*
5110 * We have loaded the private key and the server
5111 * has announced that it's willing to accept it.
5112 * Hallelujah. Generate a signature and send it.
5113 */
5114 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
5115 ssh2_pkt_addstring(ssh, s->username);
5116 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
5117 ssh2_pkt_addstring(ssh, "publickey"); /* method */
5118 ssh2_pkt_addbool(ssh, TRUE);
5119 ssh2_pkt_addstring(ssh, key->alg->name);
5120 pkblob = key->alg->public_blob(key->data, &pkblob_len);
5121 ssh2_pkt_addstring_start(ssh);
5122 ssh2_pkt_addstring_data(ssh, (char *)pkblob, pkblob_len);
5123
5124 /*
5125 * The data to be signed is:
5126 *
5127 * string session-id
5128 *
5129 * followed by everything so far placed in the
5130 * outgoing packet.
5131 */
5132 sigdata_len = ssh->pktout.length - 5 + 4 + 20;
5133 if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
5134 sigdata_len -= 4;
5135 sigdata = snewn(sigdata_len, unsigned char);
5136 p = 0;
5137 if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
5138 PUT_32BIT(sigdata+p, 20);
5139 p += 4;
5140 }
5141 memcpy(sigdata+p, ssh->v2_session_id, 20); p += 20;
5142 memcpy(sigdata+p, ssh->pktout.data + 5,
5143 ssh->pktout.length - 5);
5144 p += ssh->pktout.length - 5;
5145 assert(p == sigdata_len);
5146 sigblob = key->alg->sign(key->data, (char *)sigdata,
5147 sigdata_len, &sigblob_len);
5148 ssh2_add_sigblob(ssh, pkblob, pkblob_len,
5149 sigblob, sigblob_len);
5150 sfree(pkblob);
5151 sfree(sigblob);
5152 sfree(sigdata);
5153
5154 ssh2_pkt_send(ssh);
5155 s->type = AUTH_TYPE_PUBLICKEY;
5156 }
5157 } else if (s->method == AUTH_PASSWORD) {
5158 /*
5159 * We send the password packet lumped tightly together with
5160 * an SSH_MSG_IGNORE packet. The IGNORE packet contains a
5161 * string long enough to make the total length of the two
5162 * packets constant. This should ensure that a passive
5163 * listener doing traffic analyis can't work out the length
5164 * of the password.
5165 *
5166 * For this to work, we need an assumption about the
5167 * maximum length of the password packet. I think 256 is
5168 * pretty conservative. Anyone using a password longer than
5169 * that probably doesn't have much to worry about from
5170 * people who find out how long their password is!
5171 */
5172 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
5173 ssh2_pkt_addstring(ssh, s->username);
5174 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
5175 ssh2_pkt_addstring(ssh, "password");
5176 ssh2_pkt_addbool(ssh, FALSE);
5177 ssh2_pkt_addstring(ssh, s->password);
5178 memset(s->password, 0, sizeof(s->password));
5179 ssh2_pkt_defer(ssh);
5180 /*
5181 * We'll include a string that's an exact multiple of the
5182 * cipher block size. If the cipher is NULL for some
5183 * reason, we don't do this trick at all because we gain
5184 * nothing by it.
5185 */
5186 if (ssh->cscipher) {
5187 int stringlen, i;
5188
5189 stringlen = (256 - ssh->deferred_len);
5190 stringlen += ssh->cscipher->blksize - 1;
5191 stringlen -= (stringlen % ssh->cscipher->blksize);
5192 if (ssh->cscomp) {
5193 /*
5194 * Temporarily disable actual compression,
5195 * so we can guarantee to get this string
5196 * exactly the length we want it. The
5197 * compression-disabling routine should
5198 * return an integer indicating how many
5199 * bytes we should adjust our string length
5200 * by.
5201 */
5202 stringlen -=
5203 ssh->cscomp->disable_compression(ssh->cs_comp_ctx);
5204 }
5205 ssh2_pkt_init(ssh, SSH2_MSG_IGNORE);
5206 ssh2_pkt_addstring_start(ssh);
5207 for (i = 0; i < stringlen; i++) {
5208 char c = (char) random_byte();
5209 ssh2_pkt_addstring_data(ssh, &c, 1);
5210 }
5211 ssh2_pkt_defer(ssh);
5212 }
5213 ssh_pkt_defersend(ssh);
5214 logevent("Sent password");
5215 s->type = AUTH_TYPE_PASSWORD;
5216 } else if (s->method == AUTH_KEYBOARD_INTERACTIVE) {
5217 if (s->curr_prompt == 0) {
5218 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_INFO_RESPONSE);
5219 ssh2_pkt_adduint32(ssh, s->num_prompts);
5220 }
5221 if (s->need_pw) { /* only add pw if we just got one! */
5222 ssh2_pkt_addstring(ssh, s->password);
5223 memset(s->password, 0, sizeof(s->password));
5224 s->curr_prompt++;
5225 }
5226 if (s->curr_prompt >= s->num_prompts) {
5227 ssh2_pkt_send(ssh);
5228 } else {
5229 /*
5230 * If there are prompts remaining, we set
5231 * `gotit' so that we won't attempt to get
5232 * another packet. Then we go back round the
5233 * loop and will end up retrieving another
5234 * prompt out of the existing packet. Funky or
5235 * what?
5236 */
5237 s->gotit = TRUE;
5238 }
5239 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
5240 } else {
5241 c_write_str(ssh, "No supported authentication methods"
5242 " left to try!\r\n");
5243 logevent("No supported authentications offered."
5244 " Disconnecting");
5245 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5246 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5247 ssh2_pkt_addstring(ssh, "No supported authentication"
5248 " methods available");
5249 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5250 ssh2_pkt_send(ssh);
5251 ssh_closing((Plug)ssh, NULL, 0, 0);
5252 crStopV;
5253 }
5254 }
5255 } while (!s->we_are_in);
5256
5257 /*
5258 * Now we're authenticated for the connection protocol. The
5259 * connection protocol will automatically have started at this
5260 * point; there's no need to send SERVICE_REQUEST.
5261 */
5262
5263 /*
5264 * So now create a channel with a session in it.
5265 */
5266 ssh->channels = newtree234(ssh_channelcmp);
5267 ssh->mainchan = snew(struct ssh_channel);
5268 ssh->mainchan->ssh = ssh;
5269 ssh->mainchan->localid = alloc_channel_id(ssh);
5270 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN);
5271 ssh2_pkt_addstring(ssh, "session");
5272 ssh2_pkt_adduint32(ssh, ssh->mainchan->localid);
5273 ssh->mainchan->v.v2.locwindow = OUR_V2_WINSIZE;
5274 ssh2_pkt_adduint32(ssh, ssh->mainchan->v.v2.locwindow);/* our window size */
5275 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
5276 ssh2_pkt_send(ssh);
5277 crWaitUntilV(ispkt);
5278 if (ssh->pktin.type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
5279 bombout(("Server refused to open a session"));
5280 crStopV;
5281 /* FIXME: error data comes back in FAILURE packet */
5282 }
5283 if (ssh2_pkt_getuint32(ssh) != ssh->mainchan->localid) {
5284 bombout(("Server's channel confirmation cited wrong channel"));
5285 crStopV;
5286 }
5287 ssh->mainchan->remoteid = ssh2_pkt_getuint32(ssh);
5288 ssh->mainchan->type = CHAN_MAINSESSION;
5289 ssh->mainchan->closes = 0;
5290 ssh->mainchan->v.v2.remwindow = ssh2_pkt_getuint32(ssh);
5291 ssh->mainchan->v.v2.remmaxpkt = ssh2_pkt_getuint32(ssh);
5292 bufchain_init(&ssh->mainchan->v.v2.outbuffer);
5293 add234(ssh->channels, ssh->mainchan);
5294 logevent("Opened channel for session");
5295
5296 /*
5297 * Potentially enable X11 forwarding.
5298 */
5299 if (ssh->cfg.x11_forward) {
5300 char proto[20], data[64];
5301 logevent("Requesting X11 forwarding");
5302 ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
5303 data, sizeof(data), ssh->cfg.x11_auth);
5304 x11_get_real_auth(ssh->x11auth, ssh->cfg.x11_display);
5305 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5306 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
5307 ssh2_pkt_addstring(ssh, "x11-req");
5308 ssh2_pkt_addbool(ssh, 1); /* want reply */
5309 ssh2_pkt_addbool(ssh, 0); /* many connections */
5310 ssh2_pkt_addstring(ssh, proto);
5311 ssh2_pkt_addstring(ssh, data);
5312 ssh2_pkt_adduint32(ssh, x11_get_screen_number(ssh->cfg.x11_display));
5313 ssh2_pkt_send(ssh);
5314
5315 do {
5316 crWaitUntilV(ispkt);
5317 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5318 unsigned i = ssh2_pkt_getuint32(ssh);
5319 struct ssh_channel *c;
5320 c = find234(ssh->channels, &i, ssh_channelfind);
5321 if (!c)
5322 continue; /* nonexistent channel */
5323 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5324 }
5325 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5326
5327 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5328 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5329 bombout(("Unexpected response to X11 forwarding request:"
5330 " packet type %d", ssh->pktin.type));
5331 crStopV;
5332 }
5333 logevent("X11 forwarding refused");
5334 } else {
5335 logevent("X11 forwarding enabled");
5336 ssh->X11_fwd_enabled = TRUE;
5337 }
5338 }
5339
5340 /*
5341 * Enable port forwardings.
5342 */
5343 {
5344 char type;
5345 int n;
5346 int sport,dport,sserv,dserv;
5347 char sports[256], dports[256], saddr[256], host[256];
5348
5349 ssh->rportfwds = newtree234(ssh_rportcmp_ssh2);
5350 /* Add port forwardings. */
5351 ssh->portfwd_strptr = ssh->cfg.portfwd;
5352 while (*ssh->portfwd_strptr) {
5353 type = *ssh->portfwd_strptr++;
5354 saddr[0] = '\0';
5355 n = 0;
5356 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != '\t') {
5357 if (*ssh->portfwd_strptr == ':') {
5358 /*
5359 * We've seen a colon in the middle of the
5360 * source port number. This means that
5361 * everything we've seen until now is the
5362 * source _address_, so we'll move it into
5363 * saddr and start sports from the beginning
5364 * again.
5365 */
5366 ssh->portfwd_strptr++;
5367 sports[n] = '\0';
5368 strcpy(saddr, sports);
5369 n = 0;
5370 }
5371 if (n < 255) sports[n++] = *ssh->portfwd_strptr++;
5372 }
5373 sports[n] = 0;
5374 if (type != 'D') {
5375 if (*ssh->portfwd_strptr == '\t')
5376 ssh->portfwd_strptr++;
5377 n = 0;
5378 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':') {
5379 if (n < 255) host[n++] = *ssh->portfwd_strptr++;
5380 }
5381 host[n] = 0;
5382 if (*ssh->portfwd_strptr == ':')
5383 ssh->portfwd_strptr++;
5384 n = 0;
5385 while (*ssh->portfwd_strptr) {
5386 if (n < 255) dports[n++] = *ssh->portfwd_strptr++;
5387 }
5388 dports[n] = 0;
5389 ssh->portfwd_strptr++;
5390 dport = atoi(dports);
5391 dserv = 0;
5392 if (dport == 0) {
5393 dserv = 1;
5394 dport = net_service_lookup(dports);
5395 if (!dport) {
5396 logeventf(ssh, "Service lookup failed for destination"
5397 " port \"%s\"", dports);
5398 }
5399 }
5400 } else {
5401 while (*ssh->portfwd_strptr) ssh->portfwd_strptr++;
5402 dport = dserv = -1;
5403 }
5404 sport = atoi(sports);
5405 sserv = 0;
5406 if (sport == 0) {
5407 sserv = 1;
5408 sport = net_service_lookup(sports);
5409 if (!sport) {
5410 logeventf(ssh, "Service lookup failed for source"
5411 " port \"%s\"", sports);
5412 }
5413 }
5414 if (sport && dport) {
5415 if (type == 'L') {
5416 pfd_addforward(host, dport, *saddr ? saddr : NULL,
5417 sport, ssh, &ssh->cfg);
5418 logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
5419 " forwarding to %s:%.*s%.*s%d%.*s",
5420 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
5421 (int)(*saddr?1:0), ":",
5422 (int)(sserv ? strlen(sports) : 0), sports,
5423 sserv, "(", sport, sserv, ")",
5424 host,
5425 (int)(dserv ? strlen(dports) : 0), dports,
5426 dserv, "(", dport, dserv, ")");
5427 } else if (type == 'D') {
5428 pfd_addforward(NULL, -1, *saddr ? saddr : NULL,
5429 sport, ssh, &ssh->cfg);
5430 logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
5431 " doing SOCKS dynamic forwarding",
5432 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
5433 (int)(*saddr?1:0), ":",
5434 (int)(sserv ? strlen(sports) : 0), sports,
5435 sserv, "(", sport, sserv, ")");
5436 } else {
5437 struct ssh_rportfwd *pf;
5438 pf = snew(struct ssh_rportfwd);
5439 strcpy(pf->dhost, host);
5440 pf->dport = dport;
5441 pf->sport = sport;
5442 if (add234(ssh->rportfwds, pf) != pf) {
5443 logeventf(ssh, "Duplicate remote port forwarding"
5444 " to %s:%d", host, dport);
5445 sfree(pf);
5446 } else {
5447 logeventf(ssh, "Requesting remote port "
5448 "%.*s%.*s%.*s%.*s%d%.*s"
5449 " forward to %s:%.*s%.*s%d%.*s",
5450 (int)(*saddr?strlen(saddr):0),
5451 *saddr?saddr:NULL,
5452 (int)(*saddr?1:0), ":",
5453 (int)(sserv ? strlen(sports) : 0), sports,
5454 sserv, "(", sport, sserv, ")",
5455 host,
5456 (int)(dserv ? strlen(dports) : 0), dports,
5457 dserv, "(", dport, dserv, ")");
5458 ssh2_pkt_init(ssh, SSH2_MSG_GLOBAL_REQUEST);
5459 ssh2_pkt_addstring(ssh, "tcpip-forward");
5460 ssh2_pkt_addbool(ssh, 1);/* want reply */
5461 if (*saddr)
5462 ssh2_pkt_addstring(ssh, saddr);
5463 if (ssh->cfg.rport_acceptall)
5464 ssh2_pkt_addstring(ssh, "0.0.0.0");
5465 else
5466 ssh2_pkt_addstring(ssh, "127.0.0.1");
5467 ssh2_pkt_adduint32(ssh, sport);
5468 ssh2_pkt_send(ssh);
5469
5470 do {
5471 crWaitUntilV(ispkt);
5472 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5473 unsigned i = ssh2_pkt_getuint32(ssh);
5474 struct ssh_channel *c;
5475 c = find234(ssh->channels, &i, ssh_channelfind);
5476 if (!c)
5477 continue;/* nonexistent channel */
5478 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5479 }
5480 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5481
5482 if (ssh->pktin.type != SSH2_MSG_REQUEST_SUCCESS) {
5483 if (ssh->pktin.type != SSH2_MSG_REQUEST_FAILURE) {
5484 bombout(("Unexpected response to port "
5485 "forwarding request: packet type %d",
5486 ssh->pktin.type));
5487 crStopV;
5488 }
5489 logevent("Server refused this port forwarding");
5490 } else {
5491 logevent("Remote port forwarding enabled");
5492 }
5493 }
5494 }
5495 }
5496 }
5497 }
5498
5499 /*
5500 * Potentially enable agent forwarding.
5501 */
5502 if (ssh->cfg.agentfwd && agent_exists()) {
5503 logevent("Requesting OpenSSH-style agent forwarding");
5504 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5505 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
5506 ssh2_pkt_addstring(ssh, "auth-agent-req@openssh.com");
5507 ssh2_pkt_addbool(ssh, 1); /* want reply */
5508 ssh2_pkt_send(ssh);
5509
5510 do {
5511 crWaitUntilV(ispkt);
5512 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5513 unsigned i = ssh2_pkt_getuint32(ssh);
5514 struct ssh_channel *c;
5515 c = find234(ssh->channels, &i, ssh_channelfind);
5516 if (!c)
5517 continue; /* nonexistent channel */
5518 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5519 }
5520 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5521
5522 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5523 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5524 bombout(("Unexpected response to agent forwarding request:"
5525 " packet type %d", ssh->pktin.type));
5526 crStopV;
5527 }
5528 logevent("Agent forwarding refused");
5529 } else {
5530 logevent("Agent forwarding enabled");
5531 ssh->agentfwd_enabled = TRUE;
5532 }
5533 }
5534
5535 /*
5536 * Now allocate a pty for the session.
5537 */
5538 if (!ssh->cfg.nopty) {
5539 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5540 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid); /* recipient channel */
5541 ssh2_pkt_addstring(ssh, "pty-req");
5542 ssh2_pkt_addbool(ssh, 1); /* want reply */
5543 ssh2_pkt_addstring(ssh, ssh->cfg.termtype);
5544 ssh2_pkt_adduint32(ssh, ssh->term_width);
5545 ssh2_pkt_adduint32(ssh, ssh->term_height);
5546 ssh2_pkt_adduint32(ssh, 0); /* pixel width */
5547 ssh2_pkt_adduint32(ssh, 0); /* pixel height */
5548 ssh2_pkt_addstring_start(ssh);
5549 ssh2_pkt_addstring_data(ssh, "\0", 1); /* TTY_OP_END, no special options */
5550 ssh2_pkt_send(ssh);
5551 ssh->state = SSH_STATE_INTERMED;
5552
5553 do {
5554 crWaitUntilV(ispkt);
5555 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5556 unsigned i = ssh2_pkt_getuint32(ssh);
5557 struct ssh_channel *c;
5558 c = find234(ssh->channels, &i, ssh_channelfind);
5559 if (!c)
5560 continue; /* nonexistent channel */
5561 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5562 }
5563 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5564
5565 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5566 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5567 bombout(("Unexpected response to pty request:"
5568 " packet type %d", ssh->pktin.type));
5569 crStopV;
5570 }
5571 c_write_str(ssh, "Server refused to allocate pty\r\n");
5572 ssh->editing = ssh->echoing = 1;
5573 } else {
5574 logevent("Allocated pty");
5575 }
5576 } else {
5577 ssh->editing = ssh->echoing = 1;
5578 }
5579
5580 /*
5581 * Start a shell or a remote command. We may have to attempt
5582 * this twice if the config data has provided a second choice
5583 * of command.
5584 */
5585 while (1) {
5586 int subsys;
5587 char *cmd;
5588
5589 if (ssh->fallback_cmd) {
5590 subsys = ssh->cfg.ssh_subsys2;
5591 cmd = ssh->cfg.remote_cmd_ptr2;
5592 } else {
5593 subsys = ssh->cfg.ssh_subsys;
5594 cmd = ssh->cfg.remote_cmd_ptr;
5595 }
5596
5597 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5598 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid); /* recipient channel */
5599 if (subsys) {
5600 ssh2_pkt_addstring(ssh, "subsystem");
5601 ssh2_pkt_addbool(ssh, 1); /* want reply */
5602 ssh2_pkt_addstring(ssh, cmd);
5603 } else if (*cmd) {
5604 ssh2_pkt_addstring(ssh, "exec");
5605 ssh2_pkt_addbool(ssh, 1); /* want reply */
5606 ssh2_pkt_addstring(ssh, cmd);
5607 } else {
5608 ssh2_pkt_addstring(ssh, "shell");
5609 ssh2_pkt_addbool(ssh, 1); /* want reply */
5610 }
5611 ssh2_pkt_send(ssh);
5612 do {
5613 crWaitUntilV(ispkt);
5614 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5615 unsigned i = ssh2_pkt_getuint32(ssh);
5616 struct ssh_channel *c;
5617 c = find234(ssh->channels, &i, ssh_channelfind);
5618 if (!c)
5619 continue; /* nonexistent channel */
5620 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5621 }
5622 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5623 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5624 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5625 bombout(("Unexpected response to shell/command request:"
5626 " packet type %d", ssh->pktin.type));
5627 crStopV;
5628 }
5629 /*
5630 * We failed to start the command. If this is the
5631 * fallback command, we really are finished; if it's
5632 * not, and if the fallback command exists, try falling
5633 * back to it before complaining.
5634 */
5635 if (!ssh->fallback_cmd && ssh->cfg.remote_cmd_ptr2 != NULL) {
5636 logevent("Primary command failed; attempting fallback");
5637 ssh->fallback_cmd = TRUE;
5638 continue;
5639 }
5640 bombout(("Server refused to start a shell/command"));
5641 crStopV;
5642 } else {
5643 logevent("Started a shell/command");
5644 }
5645 break;
5646 }
5647
5648 ssh->state = SSH_STATE_SESSION;
5649 if (ssh->size_needed)
5650 ssh_size(ssh, ssh->term_width, ssh->term_height);
5651 if (ssh->eof_needed)
5652 ssh_special(ssh, TS_EOF);
5653
5654 /*
5655 * Transfer data!
5656 */
5657 if (ssh->ldisc)
5658 ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */
5659 ssh->send_ok = 1;
5660 while (1) {
5661 crReturnV;
5662 s->try_send = FALSE;
5663 if (ispkt) {
5664 if (ssh->pktin.type == SSH2_MSG_CHANNEL_DATA ||
5665 ssh->pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA) {
5666 char *data;
5667 int length;
5668 unsigned i = ssh2_pkt_getuint32(ssh);
5669 struct ssh_channel *c;
5670 c = find234(ssh->channels, &i, ssh_channelfind);
5671 if (!c)
5672 continue; /* nonexistent channel */
5673 if (ssh->pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
5674 ssh2_pkt_getuint32(ssh) != SSH2_EXTENDED_DATA_STDERR)
5675 continue; /* extended but not stderr */
5676 ssh2_pkt_getstring(ssh, &data, &length);
5677 if (data) {
5678 int bufsize = 0;
5679 c->v.v2.locwindow -= length;
5680 switch (c->type) {
5681 case CHAN_MAINSESSION:
5682 bufsize =
5683 from_backend(ssh->frontend, ssh->pktin.type ==
5684 SSH2_MSG_CHANNEL_EXTENDED_DATA,
5685 data, length);
5686 break;
5687 case CHAN_X11:
5688 bufsize = x11_send(c->u.x11.s, data, length);
5689 break;
5690 case CHAN_SOCKDATA:
5691 bufsize = pfd_send(c->u.pfd.s, data, length);
5692 break;
5693 case CHAN_AGENT:
5694 while (length > 0) {
5695 if (c->u.a.lensofar < 4) {
5696 int l = min(4 - c->u.a.lensofar, length);
5697 memcpy(c->u.a.msglen + c->u.a.lensofar,
5698 data, l);
5699 data += l;
5700 length -= l;
5701 c->u.a.lensofar += l;
5702 }
5703 if (c->u.a.lensofar == 4) {
5704 c->u.a.totallen =
5705 4 + GET_32BIT(c->u.a.msglen);
5706 c->u.a.message = snewn(c->u.a.totallen,
5707 unsigned char);
5708 memcpy(c->u.a.message, c->u.a.msglen, 4);
5709 }
5710 if (c->u.a.lensofar >= 4 && length > 0) {
5711 int l =
5712 min(c->u.a.totallen - c->u.a.lensofar,
5713 length);
5714 memcpy(c->u.a.message + c->u.a.lensofar,
5715 data, l);
5716 data += l;
5717 length -= l;
5718 c->u.a.lensofar += l;
5719 }
5720 if (c->u.a.lensofar == c->u.a.totallen) {
5721 void *reply;
5722 int replylen;
5723 if (agent_query(c->u.a.message,
5724 c->u.a.totallen,
5725 &reply, &replylen,
5726 ssh_agentf_callback, c))
5727 ssh_agentf_callback(c, reply, replylen);
5728 sfree(c->u.a.message);
5729 c->u.a.lensofar = 0;
5730 }
5731 }
5732 bufsize = 0;
5733 break;
5734 }
5735 /*
5736 * If we are not buffering too much data,
5737 * enlarge the window again at the remote side.
5738 */
5739 if (bufsize < OUR_V2_WINSIZE)
5740 ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
5741 }
5742 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_EOF) {
5743 unsigned i = ssh2_pkt_getuint32(ssh);
5744 struct ssh_channel *c;
5745
5746 c = find234(ssh->channels, &i, ssh_channelfind);
5747 if (!c)
5748 continue; /* nonexistent channel */
5749
5750 if (c->type == CHAN_X11) {
5751 /*
5752 * Remote EOF on an X11 channel means we should
5753 * wrap up and close the channel ourselves.
5754 */
5755 x11_close(c->u.x11.s);
5756 sshfwd_close(c);
5757 } else if (c->type == CHAN_AGENT) {
5758 sshfwd_close(c);
5759 } else if (c->type == CHAN_SOCKDATA) {
5760 pfd_close(c->u.pfd.s);
5761 sshfwd_close(c);
5762 }
5763 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_CLOSE) {
5764 unsigned i = ssh2_pkt_getuint32(ssh);
5765 struct ssh_channel *c;
5766
5767 c = find234(ssh->channels, &i, ssh_channelfind);
5768 if (!c || ((int)c->remoteid) == -1) {
5769 bombout(("Received CHANNEL_CLOSE for %s channel %d\n",
5770 c ? "half-open" : "nonexistent", i));
5771 crStopV;
5772 }
5773 /* Do pre-close processing on the channel. */
5774 switch (c->type) {
5775 case CHAN_MAINSESSION:
5776 break; /* nothing to see here, move along */
5777 case CHAN_X11:
5778 if (c->u.x11.s != NULL)
5779 x11_close(c->u.x11.s);
5780 sshfwd_close(c);
5781 break;
5782 case CHAN_AGENT:
5783 sshfwd_close(c);
5784 break;
5785 case CHAN_SOCKDATA:
5786 if (c->u.pfd.s != NULL)
5787 pfd_close(c->u.pfd.s);
5788 sshfwd_close(c);
5789 break;
5790 }
5791 if (c->closes == 0) {
5792 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
5793 ssh2_pkt_adduint32(ssh, c->remoteid);
5794 ssh2_pkt_send(ssh);
5795 }
5796 del234(ssh->channels, c);
5797 bufchain_clear(&c->v.v2.outbuffer);
5798 sfree(c);
5799
5800 /*
5801 * See if that was the last channel left open.
5802 */
5803 if (count234(ssh->channels) == 0) {
5804 logevent("All channels closed. Disconnecting");
5805 #if 0
5806 /*
5807 * We used to send SSH_MSG_DISCONNECT here,
5808 * because I'd believed that _every_ conforming
5809 * SSH2 connection had to end with a disconnect
5810 * being sent by at least one side; apparently
5811 * I was wrong and it's perfectly OK to
5812 * unceremoniously slam the connection shut
5813 * when you're done, and indeed OpenSSH feels
5814 * this is more polite than sending a
5815 * DISCONNECT. So now we don't.
5816 */
5817 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5818 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5819 ssh2_pkt_addstring(ssh, "All open channels closed");
5820 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5821 ssh2_pkt_send(ssh);
5822 #endif
5823 ssh_closing((Plug)ssh, NULL, 0, 0);
5824 crStopV;
5825 }
5826 continue; /* remote sends close; ignore (FIXME) */
5827 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5828 unsigned i = ssh2_pkt_getuint32(ssh);
5829 struct ssh_channel *c;
5830 c = find234(ssh->channels, &i, ssh_channelfind);
5831 if (!c || c->closes)
5832 continue; /* nonexistent or closing channel */
5833 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5834 s->try_send = TRUE;
5835 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
5836 unsigned i = ssh2_pkt_getuint32(ssh);
5837 struct ssh_channel *c;
5838 c = find234(ssh->channels, &i, ssh_channelfind);
5839 if (!c)
5840 continue; /* nonexistent channel */
5841 if (c->type != CHAN_SOCKDATA_DORMANT)
5842 continue; /* dunno why they're confirming this */
5843 c->remoteid = ssh2_pkt_getuint32(ssh);
5844 c->type = CHAN_SOCKDATA;
5845 c->v.v2.remwindow = ssh2_pkt_getuint32(ssh);
5846 c->v.v2.remmaxpkt = ssh2_pkt_getuint32(ssh);
5847 if (c->u.pfd.s)
5848 pfd_confirm(c->u.pfd.s);
5849 if (c->closes) {
5850 /*
5851 * We have a pending close on this channel,
5852 * which we decided on before the server acked
5853 * the channel open. So now we know the
5854 * remoteid, we can close it again.
5855 */
5856 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
5857 ssh2_pkt_adduint32(ssh, c->remoteid);
5858 ssh2_pkt_send(ssh);
5859 }
5860 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN_FAILURE) {
5861 unsigned i = ssh2_pkt_getuint32(ssh);
5862 struct ssh_channel *c;
5863 c = find234(ssh->channels, &i, ssh_channelfind);
5864 if (!c)
5865 continue; /* nonexistent channel */
5866 if (c->type != CHAN_SOCKDATA_DORMANT)
5867 continue; /* dunno why they're failing this */
5868
5869 logevent("Forwarded connection refused by server");
5870
5871 pfd_close(c->u.pfd.s);
5872
5873 del234(ssh->channels, c);
5874 sfree(c);
5875 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_REQUEST) {
5876 unsigned localid;
5877 char *type;
5878 int typelen, want_reply;
5879 struct ssh_channel *c;
5880
5881 localid = ssh2_pkt_getuint32(ssh);
5882 ssh2_pkt_getstring(ssh, &type, &typelen);
5883 want_reply = ssh2_pkt_getbool(ssh);
5884
5885 /*
5886 * First, check that the channel exists. Otherwise,
5887 * we can instantly disconnect with a rude message.
5888 */
5889 c = find234(ssh->channels, &localid, ssh_channelfind);
5890 if (!c) {
5891 char buf[80];
5892 sprintf(buf, "Received channel request for nonexistent"
5893 " channel %d", localid);
5894 logevent(buf);
5895 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5896 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5897 ssh2_pkt_addstring(ssh, buf);
5898 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5899 ssh2_pkt_send(ssh);
5900 connection_fatal(ssh->frontend, "%s", buf);
5901 ssh_closing((Plug)ssh, NULL, 0, 0);
5902 crStopV;
5903 }
5904
5905 /*
5906 * Having got the channel number, we now look at
5907 * the request type string to see if it's something
5908 * we recognise.
5909 */
5910 if (typelen == 11 && !memcmp(type, "exit-status", 11) &&
5911 c == ssh->mainchan) {
5912 /* We recognise "exit-status" on the primary channel. */
5913 char buf[100];
5914 ssh->exitcode = ssh2_pkt_getuint32(ssh);
5915 sprintf(buf, "Server sent command exit status %d",
5916 ssh->exitcode);
5917 logevent(buf);
5918 if (want_reply) {
5919 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_SUCCESS);
5920 ssh2_pkt_adduint32(ssh, c->remoteid);
5921 ssh2_pkt_send(ssh);
5922 }
5923 } else {
5924 /*
5925 * This is a channel request we don't know
5926 * about, so we now either ignore the request
5927 * or respond with CHANNEL_FAILURE, depending
5928 * on want_reply.
5929 */
5930 if (want_reply) {
5931 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_FAILURE);
5932 ssh2_pkt_adduint32(ssh, c->remoteid);
5933 ssh2_pkt_send(ssh);
5934 }
5935 }
5936 } else if (ssh->pktin.type == SSH2_MSG_GLOBAL_REQUEST) {
5937 char *type;
5938 int typelen, want_reply;
5939
5940 ssh2_pkt_getstring(ssh, &type, &typelen);
5941 want_reply = ssh2_pkt_getbool(ssh);
5942
5943 /*
5944 * We currently don't support any global requests
5945 * at all, so we either ignore the request or
5946 * respond with REQUEST_FAILURE, depending on
5947 * want_reply.
5948 */
5949 if (want_reply) {
5950 ssh2_pkt_init(ssh, SSH2_MSG_REQUEST_FAILURE);
5951 ssh2_pkt_send(ssh);
5952 }
5953 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN) {
5954 char *type;
5955 int typelen;
5956 char *peeraddr;
5957 int peeraddrlen;
5958 int peerport;
5959 char *error = NULL;
5960 struct ssh_channel *c;
5961 unsigned remid, winsize, pktsize;
5962 ssh2_pkt_getstring(ssh, &type, &typelen);
5963 c = snew(struct ssh_channel);
5964 c->ssh = ssh;
5965
5966 remid = ssh2_pkt_getuint32(ssh);
5967 winsize = ssh2_pkt_getuint32(ssh);
5968 pktsize = ssh2_pkt_getuint32(ssh);
5969
5970 if (typelen == 3 && !memcmp(type, "x11", 3)) {
5971 char *addrstr;
5972
5973 ssh2_pkt_getstring(ssh, &peeraddr, &peeraddrlen);
5974 addrstr = snewn(peeraddrlen+1, char);
5975 memcpy(addrstr, peeraddr, peeraddrlen);
5976 peeraddr[peeraddrlen] = '\0';
5977 peerport = ssh2_pkt_getuint32(ssh);
5978
5979 if (!ssh->X11_fwd_enabled)
5980 error = "X11 forwarding is not enabled";
5981 else if (x11_init(&c->u.x11.s, ssh->cfg.x11_display, c,
5982 ssh->x11auth, addrstr, peerport,
5983 &ssh->cfg) != NULL) {
5984 error = "Unable to open an X11 connection";
5985 } else {
5986 c->type = CHAN_X11;
5987 }
5988
5989 sfree(addrstr);
5990 } else if (typelen == 15 &&
5991 !memcmp(type, "forwarded-tcpip", 15)) {
5992 struct ssh_rportfwd pf, *realpf;
5993 char *dummy;
5994 int dummylen;
5995 ssh2_pkt_getstring(ssh, &dummy, &dummylen);/* skip address */
5996 pf.sport = ssh2_pkt_getuint32(ssh);
5997 ssh2_pkt_getstring(ssh, &peeraddr, &peeraddrlen);
5998 peerport = ssh2_pkt_getuint32(ssh);
5999 realpf = find234(ssh->rportfwds, &pf, NULL);
6000 if (realpf == NULL) {
6001 error = "Remote port is not recognised";
6002 } else {
6003 char *e = pfd_newconnect(&c->u.pfd.s, realpf->dhost,
6004 realpf->dport, c, &ssh->cfg);
6005 logeventf(ssh, "Received remote port open request"
6006 " for %s:%d", realpf->dhost, realpf->dport);
6007 if (e != NULL) {
6008 logeventf(ssh, "Port open failed: %s", e);
6009 error = "Port open failed";
6010 } else {
6011 logevent("Forwarded port opened successfully");
6012 c->type = CHAN_SOCKDATA;
6013 }
6014 }
6015 } else if (typelen == 22 &&
6016 !memcmp(type, "auth-agent@openssh.com", 3)) {
6017 if (!ssh->agentfwd_enabled)
6018 error = "Agent forwarding is not enabled";
6019 else {
6020 c->type = CHAN_AGENT; /* identify channel type */
6021 c->u.a.lensofar = 0;
6022 }
6023 } else {
6024 error = "Unsupported channel type requested";
6025 }
6026
6027 c->remoteid = remid;
6028 if (error) {
6029 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN_FAILURE);
6030 ssh2_pkt_adduint32(ssh, c->remoteid);
6031 ssh2_pkt_adduint32(ssh, SSH2_OPEN_CONNECT_FAILED);
6032 ssh2_pkt_addstring(ssh, error);
6033 ssh2_pkt_addstring(ssh, "en"); /* language tag */
6034 ssh2_pkt_send(ssh);
6035 sfree(c);
6036 } else {
6037 c->localid = alloc_channel_id(ssh);
6038 c->closes = 0;
6039 c->v.v2.locwindow = OUR_V2_WINSIZE;
6040 c->v.v2.remwindow = winsize;
6041 c->v.v2.remmaxpkt = pktsize;
6042 bufchain_init(&c->v.v2.outbuffer);
6043 add234(ssh->channels, c);
6044 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
6045 ssh2_pkt_adduint32(ssh, c->remoteid);
6046 ssh2_pkt_adduint32(ssh, c->localid);
6047 ssh2_pkt_adduint32(ssh, c->v.v2.locwindow);
6048 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
6049 ssh2_pkt_send(ssh);
6050 }
6051 } else {
6052 bombout(("Strange packet received: type %d", ssh->pktin.type));
6053 crStopV;
6054 }
6055 } else {
6056 /*
6057 * We have spare data. Add it to the channel buffer.
6058 */
6059 ssh2_add_channel_data(ssh->mainchan, (char *)in, inlen);
6060 s->try_send = TRUE;
6061 }
6062 if (s->try_send) {
6063 int i;
6064 struct ssh_channel *c;
6065 /*
6066 * Try to send data on all channels if we can.
6067 */
6068 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
6069 int bufsize;
6070 if (c->closes)
6071 continue; /* don't send on closing channels */
6072 bufsize = ssh2_try_send(c);
6073 if (bufsize == 0) {
6074 switch (c->type) {
6075 case CHAN_MAINSESSION:
6076 /* stdin need not receive an unthrottle
6077 * notification since it will be polled */
6078 break;
6079 case CHAN_X11:
6080 x11_unthrottle(c->u.x11.s);
6081 break;
6082 case CHAN_AGENT:
6083 /* agent sockets are request/response and need no
6084 * buffer management */
6085 break;
6086 case CHAN_SOCKDATA:
6087 pfd_unthrottle(c->u.pfd.s);
6088 break;
6089 }
6090 }
6091 }
6092 }
6093 }
6094
6095 crFinishV;
6096 }
6097
6098 /*
6099 * Handle the top-level SSH2 protocol.
6100 */
6101 static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
6102 {
6103 if (do_ssh2_transport(ssh, in, inlen, ispkt) == 0)
6104 return;
6105 do_ssh2_authconn(ssh, in, inlen, ispkt);
6106 }
6107
6108 /*
6109 * Called to set up the connection.
6110 *
6111 * Returns an error message, or NULL on success.
6112 */
6113 static char *ssh_init(void *frontend_handle, void **backend_handle,
6114 Config *cfg,
6115 char *host, int port, char **realhost, int nodelay)
6116 {
6117 char *p;
6118 Ssh ssh;
6119
6120 ssh = snew(struct ssh_tag);
6121 ssh->cfg = *cfg; /* STRUCTURE COPY */
6122 ssh->version = 0; /* when not ready yet */
6123 ssh->s = NULL;
6124 ssh->cipher = NULL;
6125 ssh->v1_cipher_ctx = NULL;
6126 ssh->crcda_ctx = NULL;
6127 ssh->cscipher = NULL;
6128 ssh->cs_cipher_ctx = NULL;
6129 ssh->sccipher = NULL;
6130 ssh->sc_cipher_ctx = NULL;
6131 ssh->csmac = NULL;
6132 ssh->cs_mac_ctx = NULL;
6133 ssh->scmac = NULL;
6134 ssh->sc_mac_ctx = NULL;
6135 ssh->cscomp = NULL;
6136 ssh->cs_comp_ctx = NULL;
6137 ssh->sccomp = NULL;
6138 ssh->sc_comp_ctx = NULL;
6139 ssh->kex = NULL;
6140 ssh->kex_ctx = NULL;
6141 ssh->hostkey = NULL;
6142 ssh->exitcode = -1;
6143 ssh->state = SSH_STATE_PREPACKET;
6144 ssh->size_needed = FALSE;
6145 ssh->eof_needed = FALSE;
6146 ssh->ldisc = NULL;
6147 ssh->logctx = NULL;
6148 {
6149 static const struct Packet empty = { 0, 0, NULL, NULL, 0 };
6150 ssh->pktin = ssh->pktout = empty;
6151 }
6152 ssh->deferred_send_data = NULL;
6153 ssh->deferred_len = 0;
6154 ssh->deferred_size = 0;
6155 ssh->fallback_cmd = 0;
6156 ssh->pkt_ctx = 0;
6157 ssh->x11auth = NULL;
6158 ssh->v1_compressing = FALSE;
6159 ssh->v2_outgoing_sequence = 0;
6160 ssh->ssh1_rdpkt_crstate = 0;
6161 ssh->ssh2_rdpkt_crstate = 0;
6162 ssh->do_ssh_init_crstate = 0;
6163 ssh->ssh_gotdata_crstate = 0;
6164 ssh->ssh1_protocol_crstate = 0;
6165 ssh->do_ssh1_login_crstate = 0;
6166 ssh->do_ssh2_transport_crstate = 0;
6167 ssh->do_ssh2_authconn_crstate = 0;
6168 ssh->do_ssh_init_state = NULL;
6169 ssh->do_ssh1_login_state = NULL;
6170 ssh->do_ssh2_transport_state = NULL;
6171 ssh->do_ssh2_authconn_state = NULL;
6172 ssh->mainchan = NULL;
6173 ssh->throttled_all = 0;
6174 ssh->v1_stdout_throttling = 0;
6175
6176 *backend_handle = ssh;
6177
6178 #ifdef MSCRYPTOAPI
6179 if (crypto_startup() == 0)
6180 return "Microsoft high encryption pack not installed!";
6181 #endif
6182
6183 ssh->frontend = frontend_handle;
6184 ssh->term_width = ssh->cfg.width;
6185 ssh->term_height = ssh->cfg.height;
6186
6187 ssh->channels = NULL;
6188 ssh->rportfwds = NULL;
6189
6190 ssh->send_ok = 0;
6191 ssh->editing = 0;
6192 ssh->echoing = 0;
6193 ssh->v1_throttle_count = 0;
6194 ssh->overall_bufsize = 0;
6195 ssh->fallback_cmd = 0;
6196
6197 ssh->protocol = NULL;
6198
6199 p = connect_to_host(ssh, host, port, realhost, nodelay);
6200 if (p != NULL)
6201 return p;
6202
6203 return NULL;
6204 }
6205
6206 static void ssh_free(void *handle)
6207 {
6208 Ssh ssh = (Ssh) handle;
6209 struct ssh_channel *c;
6210 struct ssh_rportfwd *pf;
6211
6212 if (ssh->v1_cipher_ctx)
6213 ssh->cipher->free_context(ssh->v1_cipher_ctx);
6214 if (ssh->cs_cipher_ctx)
6215 ssh->cscipher->free_context(ssh->cs_cipher_ctx);
6216 if (ssh->sc_cipher_ctx)
6217 ssh->sccipher->free_context(ssh->sc_cipher_ctx);
6218 if (ssh->cs_mac_ctx)
6219 ssh->csmac->free_context(ssh->cs_mac_ctx);
6220 if (ssh->sc_mac_ctx)
6221 ssh->scmac->free_context(ssh->sc_mac_ctx);
6222 if (ssh->cs_comp_ctx)
6223 ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
6224 if (ssh->sc_comp_ctx)
6225 ssh->sccomp->compress_cleanup(ssh->sc_comp_ctx);
6226 if (ssh->kex_ctx)
6227 dh_cleanup(ssh->kex_ctx);
6228 sfree(ssh->savedhost);
6229
6230 if (ssh->channels) {
6231 while ((c = delpos234(ssh->channels, 0)) != NULL) {
6232 switch (c->type) {
6233 case CHAN_X11:
6234 if (c->u.x11.s != NULL)
6235 x11_close(c->u.x11.s);
6236 break;
6237 case CHAN_SOCKDATA:
6238 if (c->u.pfd.s != NULL)
6239 pfd_close(c->u.pfd.s);
6240 break;
6241 }
6242 sfree(c);
6243 }
6244 freetree234(ssh->channels);
6245 }
6246
6247 if (ssh->rportfwds) {
6248 while ((pf = delpos234(ssh->rportfwds, 0)) != NULL)
6249 sfree(pf);
6250 freetree234(ssh->rportfwds);
6251 }
6252 sfree(ssh->deferred_send_data);
6253 if (ssh->x11auth)
6254 x11_free_auth(ssh->x11auth);
6255 sfree(ssh->do_ssh_init_state);
6256 sfree(ssh->do_ssh1_login_state);
6257 sfree(ssh->do_ssh2_transport_state);
6258 sfree(ssh->do_ssh2_authconn_state);
6259
6260 if (ssh->s)
6261 ssh_do_close(ssh);
6262 sfree(ssh);
6263 }
6264
6265 /*
6266 * Reconfigure the SSH backend.
6267 *
6268 * Currently, this function does nothing very useful. In future,
6269 * however, we could do some handy things with it. For example, we
6270 * could make the port forwarding configurer active in the Change
6271 * Settings box, and this routine could close down existing
6272 * forwardings and open up new ones in response to changes.
6273 */
6274 static void ssh_reconfig(void *handle, Config *cfg)
6275 {
6276 Ssh ssh = (Ssh) handle;
6277 ssh->cfg = *cfg; /* STRUCTURE COPY */
6278 }
6279
6280 /*
6281 * Called to send data down the Telnet connection.
6282 */
6283 static int ssh_send(void *handle, char *buf, int len)
6284 {
6285 Ssh ssh = (Ssh) handle;
6286
6287 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
6288 return 0;
6289
6290 ssh->protocol(ssh, (unsigned char *)buf, len, 0);
6291
6292 return ssh_sendbuffer(ssh);
6293 }
6294
6295 /*
6296 * Called to query the current amount of buffered stdin data.
6297 */
6298 static int ssh_sendbuffer(void *handle)
6299 {
6300 Ssh ssh = (Ssh) handle;
6301 int override_value;
6302
6303 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
6304 return 0;
6305
6306 /*
6307 * If the SSH socket itself has backed up, add the total backup
6308 * size on that to any individual buffer on the stdin channel.
6309 */
6310 override_value = 0;
6311 if (ssh->throttled_all)
6312 override_value = ssh->overall_bufsize;
6313
6314 if (ssh->version == 1) {
6315 return override_value;
6316 } else if (ssh->version == 2) {
6317 if (!ssh->mainchan || ssh->mainchan->closes > 0)
6318 return override_value;
6319 else
6320 return (override_value +
6321 bufchain_size(&ssh->mainchan->v.v2.outbuffer));
6322 }
6323
6324 return 0;
6325 }
6326
6327 /*
6328 * Called to set the size of the window from SSH's POV.
6329 */
6330 static void ssh_size(void *handle, int width, int height)
6331 {
6332 Ssh ssh = (Ssh) handle;
6333
6334 ssh->term_width = width;
6335 ssh->term_height = height;
6336
6337 switch (ssh->state) {
6338 case SSH_STATE_BEFORE_SIZE:
6339 case SSH_STATE_PREPACKET:
6340 case SSH_STATE_CLOSED:
6341 break; /* do nothing */
6342 case SSH_STATE_INTERMED:
6343 ssh->size_needed = TRUE; /* buffer for later */
6344 break;
6345 case SSH_STATE_SESSION:
6346 if (!ssh->cfg.nopty) {
6347 if (ssh->version == 1) {
6348 send_packet(ssh, SSH1_CMSG_WINDOW_SIZE,
6349 PKT_INT, ssh->term_height,
6350 PKT_INT, ssh->term_width,
6351 PKT_INT, 0, PKT_INT, 0, PKT_END);
6352 } else {
6353 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
6354 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
6355 ssh2_pkt_addstring(ssh, "window-change");
6356 ssh2_pkt_addbool(ssh, 0);
6357 ssh2_pkt_adduint32(ssh, ssh->term_width);
6358 ssh2_pkt_adduint32(ssh, ssh->term_height);
6359 ssh2_pkt_adduint32(ssh, 0);
6360 ssh2_pkt_adduint32(ssh, 0);
6361 ssh2_pkt_send(ssh);
6362 }
6363 }
6364 break;
6365 }
6366 }
6367
6368 /*
6369 * Return a list of the special codes that make sense in this
6370 * protocol.
6371 */
6372 static const struct telnet_special *ssh_get_specials(void *handle)
6373 {
6374 Ssh ssh = (Ssh) handle;
6375
6376 if (ssh->version == 1) {
6377 static const struct telnet_special ssh1_specials[] = {
6378 {"IGNORE message", TS_NOP},
6379 {NULL, 0}
6380 };
6381 return ssh1_specials;
6382 } else if (ssh->version == 2) {
6383 static const struct telnet_special ssh2_specials[] = {
6384 {"Break", TS_BRK},
6385 {"IGNORE message", TS_NOP},
6386 {NULL, 0}
6387 };
6388 return ssh2_specials;
6389 } else
6390 return NULL;
6391 }
6392
6393 /*
6394 * Send Telnet special codes. TS_EOF is useful for `plink', so you
6395 * can send an EOF and collect resulting output (e.g. `plink
6396 * hostname sort').
6397 */
6398 static void ssh_special(void *handle, Telnet_Special code)
6399 {
6400 Ssh ssh = (Ssh) handle;
6401
6402 if (code == TS_EOF) {
6403 if (ssh->state != SSH_STATE_SESSION) {
6404 /*
6405 * Buffer the EOF in case we are pre-SESSION, so we can
6406 * send it as soon as we reach SESSION.
6407 */
6408 if (code == TS_EOF)
6409 ssh->eof_needed = TRUE;
6410 return;
6411 }
6412 if (ssh->version == 1) {
6413 send_packet(ssh, SSH1_CMSG_EOF, PKT_END);
6414 } else {
6415 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_EOF);
6416 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
6417 ssh2_pkt_send(ssh);
6418 }
6419 logevent("Sent EOF message");
6420 } else if (code == TS_PING || code == TS_NOP) {
6421 if (ssh->state == SSH_STATE_CLOSED
6422 || ssh->state == SSH_STATE_PREPACKET) return;
6423 if (ssh->version == 1) {
6424 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE))
6425 send_packet(ssh, SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
6426 } else {
6427 ssh2_pkt_init(ssh, SSH2_MSG_IGNORE);
6428 ssh2_pkt_addstring_start(ssh);
6429 ssh2_pkt_send(ssh);
6430 }
6431 } else if (code == TS_BRK) {
6432 if (ssh->state == SSH_STATE_CLOSED
6433 || ssh->state == SSH_STATE_PREPACKET) return;
6434 if (ssh->version == 1) {
6435 logevent("Unable to send BREAK signal in SSH1");
6436 } else {
6437 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
6438 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
6439 ssh2_pkt_addstring(ssh, "break");
6440 ssh2_pkt_addbool(ssh, 0);
6441 ssh2_pkt_adduint32(ssh, 0); /* default break length */
6442 ssh2_pkt_send(ssh);
6443 }
6444 } else {
6445 /* do nothing */
6446 }
6447 }
6448
6449 void *new_sock_channel(void *handle, Socket s)
6450 {
6451 Ssh ssh = (Ssh) handle;
6452 struct ssh_channel *c;
6453 c = snew(struct ssh_channel);
6454 c->ssh = ssh;
6455
6456 if (c) {
6457 c->remoteid = -1; /* to be set when open confirmed */
6458 c->localid = alloc_channel_id(ssh);
6459 c->closes = 0;
6460 c->type = CHAN_SOCKDATA_DORMANT;/* identify channel type */
6461 c->u.pfd.s = s;
6462 bufchain_init(&c->v.v2.outbuffer);
6463 add234(ssh->channels, c);
6464 }
6465 return c;
6466 }
6467
6468 /*
6469 * This is called when stdout/stderr (the entity to which
6470 * from_backend sends data) manages to clear some backlog.
6471 */
6472 static void ssh_unthrottle(void *handle, int bufsize)
6473 {
6474 Ssh ssh = (Ssh) handle;
6475 if (ssh->version == 1) {
6476 if (ssh->v1_stdout_throttling && bufsize < SSH1_BUFFER_LIMIT) {
6477 ssh->v1_stdout_throttling = 0;
6478 ssh1_throttle(ssh, -1);
6479 }
6480 } else {
6481 if (ssh->mainchan && ssh->mainchan->closes == 0)
6482 ssh2_set_window(ssh->mainchan, OUR_V2_WINSIZE - bufsize);
6483 }
6484 }
6485
6486 void ssh_send_port_open(void *channel, char *hostname, int port, char *org)
6487 {
6488 struct ssh_channel *c = (struct ssh_channel *)channel;
6489 Ssh ssh = c->ssh;
6490
6491 logeventf(ssh, "Opening forwarded connection to %s:%d", hostname, port);
6492
6493 if (ssh->version == 1) {
6494 send_packet(ssh, SSH1_MSG_PORT_OPEN,
6495 PKT_INT, c->localid,
6496 PKT_STR, hostname,
6497 PKT_INT, port,
6498 //PKT_STR, <org:orgport>,
6499 PKT_END);
6500 } else {
6501 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN);
6502 ssh2_pkt_addstring(ssh, "direct-tcpip");
6503 ssh2_pkt_adduint32(ssh, c->localid);
6504 c->v.v2.locwindow = OUR_V2_WINSIZE;
6505 ssh2_pkt_adduint32(ssh, c->v.v2.locwindow);/* our window size */
6506 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
6507 ssh2_pkt_addstring(ssh, hostname);
6508 ssh2_pkt_adduint32(ssh, port);
6509 /*
6510 * We make up values for the originator data; partly it's
6511 * too much hassle to keep track, and partly I'm not
6512 * convinced the server should be told details like that
6513 * about my local network configuration.
6514 */
6515 ssh2_pkt_addstring(ssh, "client-side-connection");
6516 ssh2_pkt_adduint32(ssh, 0);
6517 ssh2_pkt_send(ssh);
6518 }
6519 }
6520
6521
6522 static Socket ssh_socket(void *handle)
6523 {
6524 Ssh ssh = (Ssh) handle;
6525 return ssh->s;
6526 }
6527
6528 static int ssh_sendok(void *handle)
6529 {
6530 Ssh ssh = (Ssh) handle;
6531 return ssh->send_ok;
6532 }
6533
6534 static int ssh_ldisc(void *handle, int option)
6535 {
6536 Ssh ssh = (Ssh) handle;
6537 if (option == LD_ECHO)
6538 return ssh->echoing;
6539 if (option == LD_EDIT)
6540 return ssh->editing;
6541 return FALSE;
6542 }
6543
6544 static void ssh_provide_ldisc(void *handle, void *ldisc)
6545 {
6546 Ssh ssh = (Ssh) handle;
6547 ssh->ldisc = ldisc;
6548 }
6549
6550 static void ssh_provide_logctx(void *handle, void *logctx)
6551 {
6552 Ssh ssh = (Ssh) handle;
6553 ssh->logctx = logctx;
6554 }
6555
6556 static int ssh_return_exitcode(void *handle)
6557 {
6558 Ssh ssh = (Ssh) handle;
6559 if (ssh->s != NULL)
6560 return -1;
6561 else
6562 return (ssh->exitcode >= 0 ? ssh->exitcode : 0);
6563 }
6564
6565 /*
6566 * Gross hack: pscp will try to start SFTP but fall back to scp1 if
6567 * that fails. This variable is the means by which scp.c can reach
6568 * into the SSH code and find out which one it got.
6569 */
6570 extern int ssh_fallback_cmd(void *handle)
6571 {
6572 Ssh ssh = (Ssh) handle;
6573 return ssh->fallback_cmd;
6574 }
6575
6576 Backend ssh_backend = {
6577 ssh_init,
6578 ssh_free,
6579 ssh_reconfig,
6580 ssh_send,
6581 ssh_sendbuffer,
6582 ssh_size,
6583 ssh_special,
6584 ssh_get_specials,
6585 ssh_socket,
6586 ssh_return_exitcode,
6587 ssh_sendok,
6588 ssh_ldisc,
6589 ssh_provide_ldisc,
6590 ssh_provide_logctx,
6591 ssh_unthrottle,
6592 22
6593 };
Local modifications for Simon Tatham's `PuTTY' SSH client and terminal emulator