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Control of 'addr' is now handed over to {platform_,}new_connection() and
[u/mdw/putty] / ssh.c
1 #include <stdio.h>
2 #include <stdlib.h>
3 #include <stdarg.h>
4 #include <assert.h>
5
6 #include "putty.h"
7 #include "tree234.h"
8 #include "ssh.h"
9
10 #ifndef FALSE
11 #define FALSE 0
12 #endif
13 #ifndef TRUE
14 #define TRUE 1
15 #endif
16
17 #define SSH1_MSG_DISCONNECT 1 /* 0x1 */
18 #define SSH1_SMSG_PUBLIC_KEY 2 /* 0x2 */
19 #define SSH1_CMSG_SESSION_KEY 3 /* 0x3 */
20 #define SSH1_CMSG_USER 4 /* 0x4 */
21 #define SSH1_CMSG_AUTH_RSA 6 /* 0x6 */
22 #define SSH1_SMSG_AUTH_RSA_CHALLENGE 7 /* 0x7 */
23 #define SSH1_CMSG_AUTH_RSA_RESPONSE 8 /* 0x8 */
24 #define SSH1_CMSG_AUTH_PASSWORD 9 /* 0x9 */
25 #define SSH1_CMSG_REQUEST_PTY 10 /* 0xa */
26 #define SSH1_CMSG_WINDOW_SIZE 11 /* 0xb */
27 #define SSH1_CMSG_EXEC_SHELL 12 /* 0xc */
28 #define SSH1_CMSG_EXEC_CMD 13 /* 0xd */
29 #define SSH1_SMSG_SUCCESS 14 /* 0xe */
30 #define SSH1_SMSG_FAILURE 15 /* 0xf */
31 #define SSH1_CMSG_STDIN_DATA 16 /* 0x10 */
32 #define SSH1_SMSG_STDOUT_DATA 17 /* 0x11 */
33 #define SSH1_SMSG_STDERR_DATA 18 /* 0x12 */
34 #define SSH1_CMSG_EOF 19 /* 0x13 */
35 #define SSH1_SMSG_EXIT_STATUS 20 /* 0x14 */
36 #define SSH1_MSG_CHANNEL_OPEN_CONFIRMATION 21 /* 0x15 */
37 #define SSH1_MSG_CHANNEL_OPEN_FAILURE 22 /* 0x16 */
38 #define SSH1_MSG_CHANNEL_DATA 23 /* 0x17 */
39 #define SSH1_MSG_CHANNEL_CLOSE 24 /* 0x18 */
40 #define SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION 25 /* 0x19 */
41 #define SSH1_SMSG_X11_OPEN 27 /* 0x1b */
42 #define SSH1_CMSG_PORT_FORWARD_REQUEST 28 /* 0x1c */
43 #define SSH1_MSG_PORT_OPEN 29 /* 0x1d */
44 #define SSH1_CMSG_AGENT_REQUEST_FORWARDING 30 /* 0x1e */
45 #define SSH1_SMSG_AGENT_OPEN 31 /* 0x1f */
46 #define SSH1_MSG_IGNORE 32 /* 0x20 */
47 #define SSH1_CMSG_EXIT_CONFIRMATION 33 /* 0x21 */
48 #define SSH1_CMSG_X11_REQUEST_FORWARDING 34 /* 0x22 */
49 #define SSH1_CMSG_AUTH_RHOSTS_RSA 35 /* 0x23 */
50 #define SSH1_MSG_DEBUG 36 /* 0x24 */
51 #define SSH1_CMSG_REQUEST_COMPRESSION 37 /* 0x25 */
52 #define SSH1_CMSG_AUTH_TIS 39 /* 0x27 */
53 #define SSH1_SMSG_AUTH_TIS_CHALLENGE 40 /* 0x28 */
54 #define SSH1_CMSG_AUTH_TIS_RESPONSE 41 /* 0x29 */
55 #define SSH1_CMSG_AUTH_CCARD 70 /* 0x46 */
56 #define SSH1_SMSG_AUTH_CCARD_CHALLENGE 71 /* 0x47 */
57 #define SSH1_CMSG_AUTH_CCARD_RESPONSE 72 /* 0x48 */
58
59 #define SSH1_AUTH_TIS 5 /* 0x5 */
60 #define SSH1_AUTH_CCARD 16 /* 0x10 */
61
62 #define SSH1_PROTOFLAG_SCREEN_NUMBER 1 /* 0x1 */
63 /* Mask for protoflags we will echo back to server if seen */
64 #define SSH1_PROTOFLAGS_SUPPORTED 0 /* 0x1 */
65
66 #define SSH2_MSG_DISCONNECT 1 /* 0x1 */
67 #define SSH2_MSG_IGNORE 2 /* 0x2 */
68 #define SSH2_MSG_UNIMPLEMENTED 3 /* 0x3 */
69 #define SSH2_MSG_DEBUG 4 /* 0x4 */
70 #define SSH2_MSG_SERVICE_REQUEST 5 /* 0x5 */
71 #define SSH2_MSG_SERVICE_ACCEPT 6 /* 0x6 */
72 #define SSH2_MSG_KEXINIT 20 /* 0x14 */
73 #define SSH2_MSG_NEWKEYS 21 /* 0x15 */
74 #define SSH2_MSG_KEXDH_INIT 30 /* 0x1e */
75 #define SSH2_MSG_KEXDH_REPLY 31 /* 0x1f */
76 #define SSH2_MSG_KEX_DH_GEX_REQUEST 30 /* 0x1e */
77 #define SSH2_MSG_KEX_DH_GEX_GROUP 31 /* 0x1f */
78 #define SSH2_MSG_KEX_DH_GEX_INIT 32 /* 0x20 */
79 #define SSH2_MSG_KEX_DH_GEX_REPLY 33 /* 0x21 */
80 #define SSH2_MSG_USERAUTH_REQUEST 50 /* 0x32 */
81 #define SSH2_MSG_USERAUTH_FAILURE 51 /* 0x33 */
82 #define SSH2_MSG_USERAUTH_SUCCESS 52 /* 0x34 */
83 #define SSH2_MSG_USERAUTH_BANNER 53 /* 0x35 */
84 #define SSH2_MSG_USERAUTH_PK_OK 60 /* 0x3c */
85 #define SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ 60 /* 0x3c */
86 #define SSH2_MSG_USERAUTH_INFO_REQUEST 60 /* 0x3c */
87 #define SSH2_MSG_USERAUTH_INFO_RESPONSE 61 /* 0x3d */
88 #define SSH2_MSG_GLOBAL_REQUEST 80 /* 0x50 */
89 #define SSH2_MSG_REQUEST_SUCCESS 81 /* 0x51 */
90 #define SSH2_MSG_REQUEST_FAILURE 82 /* 0x52 */
91 #define SSH2_MSG_CHANNEL_OPEN 90 /* 0x5a */
92 #define SSH2_MSG_CHANNEL_OPEN_CONFIRMATION 91 /* 0x5b */
93 #define SSH2_MSG_CHANNEL_OPEN_FAILURE 92 /* 0x5c */
94 #define SSH2_MSG_CHANNEL_WINDOW_ADJUST 93 /* 0x5d */
95 #define SSH2_MSG_CHANNEL_DATA 94 /* 0x5e */
96 #define SSH2_MSG_CHANNEL_EXTENDED_DATA 95 /* 0x5f */
97 #define SSH2_MSG_CHANNEL_EOF 96 /* 0x60 */
98 #define SSH2_MSG_CHANNEL_CLOSE 97 /* 0x61 */
99 #define SSH2_MSG_CHANNEL_REQUEST 98 /* 0x62 */
100 #define SSH2_MSG_CHANNEL_SUCCESS 99 /* 0x63 */
101 #define SSH2_MSG_CHANNEL_FAILURE 100 /* 0x64 */
102
103 /*
104 * Packet type contexts, so that ssh2_pkt_type can correctly decode
105 * the ambiguous type numbers back into the correct type strings.
106 */
107 #define SSH2_PKTCTX_DHGROUP1 0x0001
108 #define SSH2_PKTCTX_DHGEX 0x0002
109 #define SSH2_PKTCTX_PUBLICKEY 0x0010
110 #define SSH2_PKTCTX_PASSWORD 0x0020
111 #define SSH2_PKTCTX_KBDINTER 0x0040
112 #define SSH2_PKTCTX_AUTH_MASK 0x00F0
113
114 #define SSH2_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT 1 /* 0x1 */
115 #define SSH2_DISCONNECT_PROTOCOL_ERROR 2 /* 0x2 */
116 #define SSH2_DISCONNECT_KEY_EXCHANGE_FAILED 3 /* 0x3 */
117 #define SSH2_DISCONNECT_HOST_AUTHENTICATION_FAILED 4 /* 0x4 */
118 #define SSH2_DISCONNECT_MAC_ERROR 5 /* 0x5 */
119 #define SSH2_DISCONNECT_COMPRESSION_ERROR 6 /* 0x6 */
120 #define SSH2_DISCONNECT_SERVICE_NOT_AVAILABLE 7 /* 0x7 */
121 #define SSH2_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED 8 /* 0x8 */
122 #define SSH2_DISCONNECT_HOST_KEY_NOT_VERIFIABLE 9 /* 0x9 */
123 #define SSH2_DISCONNECT_CONNECTION_LOST 10 /* 0xa */
124 #define SSH2_DISCONNECT_BY_APPLICATION 11 /* 0xb */
125 #define SSH2_DISCONNECT_TOO_MANY_CONNECTIONS 12 /* 0xc */
126 #define SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER 13 /* 0xd */
127 #define SSH2_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE 14 /* 0xe */
128 #define SSH2_DISCONNECT_ILLEGAL_USER_NAME 15 /* 0xf */
129
130 static const char *const ssh2_disconnect_reasons[] = {
131 NULL,
132 "SSH_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT",
133 "SSH_DISCONNECT_PROTOCOL_ERROR",
134 "SSH_DISCONNECT_KEY_EXCHANGE_FAILED",
135 "SSH_DISCONNECT_HOST_AUTHENTICATION_FAILED",
136 "SSH_DISCONNECT_MAC_ERROR",
137 "SSH_DISCONNECT_COMPRESSION_ERROR",
138 "SSH_DISCONNECT_SERVICE_NOT_AVAILABLE",
139 "SSH_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED",
140 "SSH_DISCONNECT_HOST_KEY_NOT_VERIFIABLE",
141 "SSH_DISCONNECT_CONNECTION_LOST",
142 "SSH_DISCONNECT_BY_APPLICATION",
143 "SSH_DISCONNECT_TOO_MANY_CONNECTIONS",
144 "SSH_DISCONNECT_AUTH_CANCELLED_BY_USER",
145 "SSH_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE",
146 "SSH_DISCONNECT_ILLEGAL_USER_NAME",
147 };
148
149 #define SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED 1 /* 0x1 */
150 #define SSH2_OPEN_CONNECT_FAILED 2 /* 0x2 */
151 #define SSH2_OPEN_UNKNOWN_CHANNEL_TYPE 3 /* 0x3 */
152 #define SSH2_OPEN_RESOURCE_SHORTAGE 4 /* 0x4 */
153
154 #define SSH2_EXTENDED_DATA_STDERR 1 /* 0x1 */
155
156 /*
157 * Various remote-bug flags.
158 */
159 #define BUG_CHOKES_ON_SSH1_IGNORE 1
160 #define BUG_SSH2_HMAC 2
161 #define BUG_NEEDS_SSH1_PLAIN_PASSWORD 4
162 #define BUG_CHOKES_ON_RSA 8
163 #define BUG_SSH2_RSA_PADDING 16
164 #define BUG_SSH2_DERIVEKEY 32
165 #define BUG_SSH2_DH_GEX 64
166 #define BUG_SSH2_PK_SESSIONID 128
167
168 #define translate(x) if (type == x) return #x
169 #define translatec(x,ctx) if (type == x && (pkt_ctx & ctx)) return #x
170 static char *ssh1_pkt_type(int type)
171 {
172 translate(SSH1_MSG_DISCONNECT);
173 translate(SSH1_SMSG_PUBLIC_KEY);
174 translate(SSH1_CMSG_SESSION_KEY);
175 translate(SSH1_CMSG_USER);
176 translate(SSH1_CMSG_AUTH_RSA);
177 translate(SSH1_SMSG_AUTH_RSA_CHALLENGE);
178 translate(SSH1_CMSG_AUTH_RSA_RESPONSE);
179 translate(SSH1_CMSG_AUTH_PASSWORD);
180 translate(SSH1_CMSG_REQUEST_PTY);
181 translate(SSH1_CMSG_WINDOW_SIZE);
182 translate(SSH1_CMSG_EXEC_SHELL);
183 translate(SSH1_CMSG_EXEC_CMD);
184 translate(SSH1_SMSG_SUCCESS);
185 translate(SSH1_SMSG_FAILURE);
186 translate(SSH1_CMSG_STDIN_DATA);
187 translate(SSH1_SMSG_STDOUT_DATA);
188 translate(SSH1_SMSG_STDERR_DATA);
189 translate(SSH1_CMSG_EOF);
190 translate(SSH1_SMSG_EXIT_STATUS);
191 translate(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION);
192 translate(SSH1_MSG_CHANNEL_OPEN_FAILURE);
193 translate(SSH1_MSG_CHANNEL_DATA);
194 translate(SSH1_MSG_CHANNEL_CLOSE);
195 translate(SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION);
196 translate(SSH1_SMSG_X11_OPEN);
197 translate(SSH1_CMSG_PORT_FORWARD_REQUEST);
198 translate(SSH1_MSG_PORT_OPEN);
199 translate(SSH1_CMSG_AGENT_REQUEST_FORWARDING);
200 translate(SSH1_SMSG_AGENT_OPEN);
201 translate(SSH1_MSG_IGNORE);
202 translate(SSH1_CMSG_EXIT_CONFIRMATION);
203 translate(SSH1_CMSG_X11_REQUEST_FORWARDING);
204 translate(SSH1_CMSG_AUTH_RHOSTS_RSA);
205 translate(SSH1_MSG_DEBUG);
206 translate(SSH1_CMSG_REQUEST_COMPRESSION);
207 translate(SSH1_CMSG_AUTH_TIS);
208 translate(SSH1_SMSG_AUTH_TIS_CHALLENGE);
209 translate(SSH1_CMSG_AUTH_TIS_RESPONSE);
210 translate(SSH1_CMSG_AUTH_CCARD);
211 translate(SSH1_SMSG_AUTH_CCARD_CHALLENGE);
212 translate(SSH1_CMSG_AUTH_CCARD_RESPONSE);
213 return "unknown";
214 }
215 static char *ssh2_pkt_type(int pkt_ctx, int type)
216 {
217 translate(SSH2_MSG_DISCONNECT);
218 translate(SSH2_MSG_IGNORE);
219 translate(SSH2_MSG_UNIMPLEMENTED);
220 translate(SSH2_MSG_DEBUG);
221 translate(SSH2_MSG_SERVICE_REQUEST);
222 translate(SSH2_MSG_SERVICE_ACCEPT);
223 translate(SSH2_MSG_KEXINIT);
224 translate(SSH2_MSG_NEWKEYS);
225 translatec(SSH2_MSG_KEXDH_INIT, SSH2_PKTCTX_DHGROUP1);
226 translatec(SSH2_MSG_KEXDH_REPLY, SSH2_PKTCTX_DHGROUP1);
227 translatec(SSH2_MSG_KEX_DH_GEX_REQUEST, SSH2_PKTCTX_DHGEX);
228 translatec(SSH2_MSG_KEX_DH_GEX_GROUP, SSH2_PKTCTX_DHGEX);
229 translatec(SSH2_MSG_KEX_DH_GEX_INIT, SSH2_PKTCTX_DHGEX);
230 translatec(SSH2_MSG_KEX_DH_GEX_REPLY, SSH2_PKTCTX_DHGEX);
231 translate(SSH2_MSG_USERAUTH_REQUEST);
232 translate(SSH2_MSG_USERAUTH_FAILURE);
233 translate(SSH2_MSG_USERAUTH_SUCCESS);
234 translate(SSH2_MSG_USERAUTH_BANNER);
235 translatec(SSH2_MSG_USERAUTH_PK_OK, SSH2_PKTCTX_PUBLICKEY);
236 translatec(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, SSH2_PKTCTX_PASSWORD);
237 translatec(SSH2_MSG_USERAUTH_INFO_REQUEST, SSH2_PKTCTX_KBDINTER);
238 translatec(SSH2_MSG_USERAUTH_INFO_RESPONSE, SSH2_PKTCTX_KBDINTER);
239 translate(SSH2_MSG_GLOBAL_REQUEST);
240 translate(SSH2_MSG_REQUEST_SUCCESS);
241 translate(SSH2_MSG_REQUEST_FAILURE);
242 translate(SSH2_MSG_CHANNEL_OPEN);
243 translate(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
244 translate(SSH2_MSG_CHANNEL_OPEN_FAILURE);
245 translate(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
246 translate(SSH2_MSG_CHANNEL_DATA);
247 translate(SSH2_MSG_CHANNEL_EXTENDED_DATA);
248 translate(SSH2_MSG_CHANNEL_EOF);
249 translate(SSH2_MSG_CHANNEL_CLOSE);
250 translate(SSH2_MSG_CHANNEL_REQUEST);
251 translate(SSH2_MSG_CHANNEL_SUCCESS);
252 translate(SSH2_MSG_CHANNEL_FAILURE);
253 return "unknown";
254 }
255 #undef translate
256 #undef translatec
257
258 #define GET_32BIT(cp) \
259 (((unsigned long)(unsigned char)(cp)[0] << 24) | \
260 ((unsigned long)(unsigned char)(cp)[1] << 16) | \
261 ((unsigned long)(unsigned char)(cp)[2] << 8) | \
262 ((unsigned long)(unsigned char)(cp)[3]))
263
264 #define PUT_32BIT(cp, value) { \
265 (cp)[0] = (unsigned char)((value) >> 24); \
266 (cp)[1] = (unsigned char)((value) >> 16); \
267 (cp)[2] = (unsigned char)((value) >> 8); \
268 (cp)[3] = (unsigned char)(value); }
269
270 enum { PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR, PKT_BIGNUM };
271
272 /*
273 * Coroutine mechanics for the sillier bits of the code. If these
274 * macros look impenetrable to you, you might find it helpful to
275 * read
276 *
277 * http://www.chiark.greenend.org.uk/~sgtatham/coroutines.html
278 *
279 * which explains the theory behind these macros.
280 *
281 * In particular, if you are getting `case expression not constant'
282 * errors when building with MS Visual Studio, this is because MS's
283 * Edit and Continue debugging feature causes their compiler to
284 * violate ANSI C. To disable Edit and Continue debugging:
285 *
286 * - right-click ssh.c in the FileView
287 * - click Settings
288 * - select the C/C++ tab and the General category
289 * - under `Debug info:', select anything _other_ than `Program
290 * Database for Edit and Continue'.
291 */
292 #define crBegin(v) { int *crLine = &v; switch(v) { case 0:;
293 #define crState(t) \
294 struct t *s; \
295 if (!ssh->t) ssh->t = snew(struct t); \
296 s = ssh->t;
297 #define crFinish(z) } *crLine = 0; return (z); }
298 #define crFinishV } *crLine = 0; return; }
299 #define crReturn(z) \
300 do {\
301 *crLine =__LINE__; return (z); case __LINE__:;\
302 } while (0)
303 #define crReturnV \
304 do {\
305 *crLine=__LINE__; return; case __LINE__:;\
306 } while (0)
307 #define crStop(z) do{ *crLine = 0; return (z); }while(0)
308 #define crStopV do{ *crLine = 0; return; }while(0)
309 #define crWaitUntil(c) do { crReturn(0); } while (!(c))
310 #define crWaitUntilV(c) do { crReturnV; } while (!(c))
311
312 typedef struct ssh_tag *Ssh;
313
314 static void ssh2_pkt_init(Ssh, int pkt_type);
315 static void ssh2_pkt_addbool(Ssh, unsigned char value);
316 static void ssh2_pkt_adduint32(Ssh, unsigned long value);
317 static void ssh2_pkt_addstring_start(Ssh);
318 static void ssh2_pkt_addstring_str(Ssh, char *data);
319 static void ssh2_pkt_addstring_data(Ssh, char *data, int len);
320 static void ssh2_pkt_addstring(Ssh, char *data);
321 static unsigned char *ssh2_mpint_fmt(Bignum b, int *len);
322 static void ssh2_pkt_addmp(Ssh, Bignum b);
323 static int ssh2_pkt_construct(Ssh);
324 static void ssh2_pkt_send(Ssh);
325 static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt);
326 static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt);
327
328 /*
329 * Buffer management constants. There are several of these for
330 * various different purposes:
331 *
332 * - SSH1_BUFFER_LIMIT is the amount of backlog that must build up
333 * on a local data stream before we throttle the whole SSH
334 * connection (in SSH1 only). Throttling the whole connection is
335 * pretty drastic so we set this high in the hope it won't
336 * happen very often.
337 *
338 * - SSH_MAX_BACKLOG is the amount of backlog that must build up
339 * on the SSH connection itself before we defensively throttle
340 * _all_ local data streams. This is pretty drastic too (though
341 * thankfully unlikely in SSH2 since the window mechanism should
342 * ensure that the server never has any need to throttle its end
343 * of the connection), so we set this high as well.
344 *
345 * - OUR_V2_WINSIZE is the maximum window size we present on SSH2
346 * channels.
347 */
348
349 #define SSH1_BUFFER_LIMIT 32768
350 #define SSH_MAX_BACKLOG 32768
351 #define OUR_V2_WINSIZE 16384
352
353 const static struct ssh_kex *kex_algs[] = {
354 &ssh_diffiehellman_gex,
355 &ssh_diffiehellman
356 };
357
358 const static struct ssh_signkey *hostkey_algs[] = { &ssh_rsa, &ssh_dss };
359
360 static void *nullmac_make_context(void)
361 {
362 return NULL;
363 }
364 static void nullmac_free_context(void *handle)
365 {
366 }
367 static void nullmac_key(void *handle, unsigned char *key)
368 {
369 }
370 static void nullmac_generate(void *handle, unsigned char *blk, int len,
371 unsigned long seq)
372 {
373 }
374 static int nullmac_verify(void *handle, unsigned char *blk, int len,
375 unsigned long seq)
376 {
377 return 1;
378 }
379 const static struct ssh_mac ssh_mac_none = {
380 nullmac_make_context, nullmac_free_context, nullmac_key,
381 nullmac_generate, nullmac_verify, "none", 0
382 };
383 const static struct ssh_mac *macs[] = {
384 &ssh_sha1, &ssh_md5, &ssh_mac_none
385 };
386 const static struct ssh_mac *buggymacs[] = {
387 &ssh_sha1_buggy, &ssh_md5, &ssh_mac_none
388 };
389
390 static void *ssh_comp_none_init(void)
391 {
392 return NULL;
393 }
394 static void ssh_comp_none_cleanup(void *handle)
395 {
396 }
397 static int ssh_comp_none_block(void *handle, unsigned char *block, int len,
398 unsigned char **outblock, int *outlen)
399 {
400 return 0;
401 }
402 static int ssh_comp_none_disable(void *handle)
403 {
404 return 0;
405 }
406 const static struct ssh_compress ssh_comp_none = {
407 "none",
408 ssh_comp_none_init, ssh_comp_none_cleanup, ssh_comp_none_block,
409 ssh_comp_none_init, ssh_comp_none_cleanup, ssh_comp_none_block,
410 ssh_comp_none_disable, NULL
411 };
412 extern const struct ssh_compress ssh_zlib;
413 const static struct ssh_compress *compressions[] = {
414 &ssh_zlib, &ssh_comp_none
415 };
416
417 enum { /* channel types */
418 CHAN_MAINSESSION,
419 CHAN_X11,
420 CHAN_AGENT,
421 CHAN_SOCKDATA,
422 CHAN_SOCKDATA_DORMANT /* one the remote hasn't confirmed */
423 };
424
425 /*
426 * 2-3-4 tree storing channels.
427 */
428 struct ssh_channel {
429 Ssh ssh; /* pointer back to main context */
430 unsigned remoteid, localid;
431 int type;
432 /*
433 * In SSH1, this value contains four bits:
434 *
435 * 1 We have sent SSH1_MSG_CHANNEL_CLOSE.
436 * 2 We have sent SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION.
437 * 4 We have received SSH1_MSG_CHANNEL_CLOSE.
438 * 8 We have received SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION.
439 *
440 * A channel is completely finished with when all four bits are set.
441 */
442 int closes;
443 union {
444 struct ssh1_data_channel {
445 int throttling;
446 } v1;
447 struct ssh2_data_channel {
448 bufchain outbuffer;
449 unsigned remwindow, remmaxpkt;
450 unsigned locwindow;
451 } v2;
452 } v;
453 union {
454 struct ssh_agent_channel {
455 unsigned char *message;
456 unsigned char msglen[4];
457 int lensofar, totallen;
458 } a;
459 struct ssh_x11_channel {
460 Socket s;
461 } x11;
462 struct ssh_pfd_channel {
463 Socket s;
464 } pfd;
465 } u;
466 };
467
468 /*
469 * 2-3-4 tree storing remote->local port forwardings. SSH 1 and SSH
470 * 2 use this structure in different ways, reflecting SSH 2's
471 * altogether saner approach to port forwarding.
472 *
473 * In SSH 1, you arrange a remote forwarding by sending the server
474 * the remote port number, and the local destination host:port.
475 * When a connection comes in, the server sends you back that
476 * host:port pair, and you connect to it. This is a ready-made
477 * security hole if you're not on the ball: a malicious server
478 * could send you back _any_ host:port pair, so if you trustingly
479 * connect to the address it gives you then you've just opened the
480 * entire inside of your corporate network just by connecting
481 * through it to a dodgy SSH server. Hence, we must store a list of
482 * host:port pairs we _are_ trying to forward to, and reject a
483 * connection request from the server if it's not in the list.
484 *
485 * In SSH 2, each side of the connection minds its own business and
486 * doesn't send unnecessary information to the other. You arrange a
487 * remote forwarding by sending the server just the remote port
488 * number. When a connection comes in, the server tells you which
489 * of its ports was connected to; and _you_ have to remember what
490 * local host:port pair went with that port number.
491 *
492 * Hence: in SSH 1 this structure stores host:port pairs we intend
493 * to allow connections to, and is indexed by those host:port
494 * pairs. In SSH 2 it stores a mapping from source port to
495 * destination host:port pair, and is indexed by source port.
496 */
497 struct ssh_rportfwd {
498 unsigned sport, dport;
499 char dhost[256];
500 };
501
502 struct Packet {
503 long length;
504 int type;
505 unsigned char *data;
506 unsigned char *body;
507 long savedpos;
508 long maxlen;
509 };
510
511 static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt);
512 static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt);
513 static void ssh_size(void *handle, int width, int height);
514 static void ssh_special(void *handle, Telnet_Special);
515 static int ssh2_try_send(struct ssh_channel *c);
516 static void ssh2_add_channel_data(struct ssh_channel *c, char *buf, int len);
517 static void ssh_throttle_all(Ssh ssh, int enable, int bufsize);
518 static void ssh2_set_window(struct ssh_channel *c, unsigned newwin);
519 static int ssh_sendbuffer(void *handle);
520 static void ssh_do_close(Ssh ssh);
521
522 struct rdpkt1_state_tag {
523 long len, pad, biglen, to_read;
524 unsigned long realcrc, gotcrc;
525 unsigned char *p;
526 int i;
527 int chunk;
528 };
529
530 struct rdpkt2_state_tag {
531 long len, pad, payload, packetlen, maclen;
532 int i;
533 int cipherblk;
534 unsigned long incoming_sequence;
535 };
536
537 struct ssh_tag {
538 const struct plug_function_table *fn;
539 /* the above field _must_ be first in the structure */
540
541 SHA_State exhash, exhashbase;
542
543 Socket s;
544
545 void *ldisc;
546 void *logctx;
547
548 unsigned char session_key[32];
549 int v1_compressing;
550 int v1_remote_protoflags;
551 int v1_local_protoflags;
552 int agentfwd_enabled;
553 int X11_fwd_enabled;
554 int remote_bugs;
555 const struct ssh_cipher *cipher;
556 void *v1_cipher_ctx;
557 void *crcda_ctx;
558 const struct ssh2_cipher *cscipher, *sccipher;
559 void *cs_cipher_ctx, *sc_cipher_ctx;
560 const struct ssh_mac *csmac, *scmac;
561 void *cs_mac_ctx, *sc_mac_ctx;
562 const struct ssh_compress *cscomp, *sccomp;
563 void *cs_comp_ctx, *sc_comp_ctx;
564 const struct ssh_kex *kex;
565 const struct ssh_signkey *hostkey;
566 unsigned char v2_session_id[20];
567 void *kex_ctx;
568
569 char *savedhost;
570 int savedport;
571 int send_ok;
572 int echoing, editing;
573
574 void *frontend;
575
576 int term_width, term_height;
577
578 tree234 *channels; /* indexed by local id */
579 struct ssh_channel *mainchan; /* primary session channel */
580 int exitcode;
581
582 tree234 *rportfwds;
583
584 enum {
585 SSH_STATE_PREPACKET,
586 SSH_STATE_BEFORE_SIZE,
587 SSH_STATE_INTERMED,
588 SSH_STATE_SESSION,
589 SSH_STATE_CLOSED
590 } state;
591
592 int size_needed, eof_needed;
593
594 struct Packet pktin;
595 struct Packet pktout;
596 unsigned char *deferred_send_data;
597 int deferred_len, deferred_size;
598
599 /*
600 * Gross hack: pscp will try to start SFTP but fall back to
601 * scp1 if that fails. This variable is the means by which
602 * scp.c can reach into the SSH code and find out which one it
603 * got.
604 */
605 int fallback_cmd;
606
607 /*
608 * Used for username and password input.
609 */
610 char *userpass_input_buffer;
611 int userpass_input_buflen;
612 int userpass_input_bufpos;
613 int userpass_input_echo;
614
615 char *portfwd_strptr;
616 int pkt_ctx;
617
618 void *x11auth;
619
620 int version;
621 int v1_throttle_count;
622 int overall_bufsize;
623 int throttled_all;
624 int v1_stdout_throttling;
625 int v2_outgoing_sequence;
626
627 int ssh1_rdpkt_crstate;
628 int ssh2_rdpkt_crstate;
629 int do_ssh_init_crstate;
630 int ssh_gotdata_crstate;
631 int ssh1_protocol_crstate;
632 int do_ssh1_login_crstate;
633 int do_ssh2_transport_crstate;
634 int do_ssh2_authconn_crstate;
635
636 void *do_ssh_init_state;
637 void *do_ssh1_login_state;
638 void *do_ssh2_transport_state;
639 void *do_ssh2_authconn_state;
640
641 struct rdpkt1_state_tag rdpkt1_state;
642 struct rdpkt2_state_tag rdpkt2_state;
643
644 void (*protocol) (Ssh ssh, unsigned char *in, int inlen, int ispkt);
645 int (*s_rdpkt) (Ssh ssh, unsigned char **data, int *datalen);
646
647 /*
648 * We maintain a full _copy_ of a Config structure here, not
649 * merely a pointer to it. That way, when we're passed a new
650 * one for reconfiguration, we can check the differences and
651 * potentially reconfigure port forwardings etc in mid-session.
652 */
653 Config cfg;
654
655 /*
656 * Used to transfer data back from async agent callbacks.
657 */
658 void *agent_response;
659 int agent_response_len;
660 };
661
662 #define logevent(s) logevent(ssh->frontend, s)
663
664 /* logevent, only printf-formatted. */
665 static void logeventf(Ssh ssh, const char *fmt, ...)
666 {
667 va_list ap;
668 char *buf;
669
670 va_start(ap, fmt);
671 buf = dupvprintf(fmt, ap);
672 va_end(ap);
673 logevent(buf);
674 sfree(buf);
675 }
676
677 #define bombout(msg) \
678 do { \
679 char *text = dupprintf msg; \
680 ssh_do_close(ssh); \
681 logevent(text); \
682 connection_fatal(ssh->frontend, "%s", text); \
683 sfree(text); \
684 } while (0)
685
686 static int ssh_channelcmp(void *av, void *bv)
687 {
688 struct ssh_channel *a = (struct ssh_channel *) av;
689 struct ssh_channel *b = (struct ssh_channel *) bv;
690 if (a->localid < b->localid)
691 return -1;
692 if (a->localid > b->localid)
693 return +1;
694 return 0;
695 }
696 static int ssh_channelfind(void *av, void *bv)
697 {
698 unsigned *a = (unsigned *) av;
699 struct ssh_channel *b = (struct ssh_channel *) bv;
700 if (*a < b->localid)
701 return -1;
702 if (*a > b->localid)
703 return +1;
704 return 0;
705 }
706
707 static int ssh_rportcmp_ssh1(void *av, void *bv)
708 {
709 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
710 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
711 int i;
712 if ( (i = strcmp(a->dhost, b->dhost)) != 0)
713 return i < 0 ? -1 : +1;
714 if (a->dport > b->dport)
715 return +1;
716 if (a->dport < b->dport)
717 return -1;
718 return 0;
719 }
720
721 static int ssh_rportcmp_ssh2(void *av, void *bv)
722 {
723 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
724 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
725
726 if (a->sport > b->sport)
727 return +1;
728 if (a->sport < b->sport)
729 return -1;
730 return 0;
731 }
732
733 static int alloc_channel_id(Ssh ssh)
734 {
735 const unsigned CHANNEL_NUMBER_OFFSET = 256;
736 unsigned low, high, mid;
737 int tsize;
738 struct ssh_channel *c;
739
740 /*
741 * First-fit allocation of channel numbers: always pick the
742 * lowest unused one. To do this, binary-search using the
743 * counted B-tree to find the largest channel ID which is in a
744 * contiguous sequence from the beginning. (Precisely
745 * everything in that sequence must have ID equal to its tree
746 * index plus CHANNEL_NUMBER_OFFSET.)
747 */
748 tsize = count234(ssh->channels);
749
750 low = -1;
751 high = tsize;
752 while (high - low > 1) {
753 mid = (high + low) / 2;
754 c = index234(ssh->channels, mid);
755 if (c->localid == mid + CHANNEL_NUMBER_OFFSET)
756 low = mid; /* this one is fine */
757 else
758 high = mid; /* this one is past it */
759 }
760 /*
761 * Now low points to either -1, or the tree index of the
762 * largest ID in the initial sequence.
763 */
764 {
765 unsigned i = low + 1 + CHANNEL_NUMBER_OFFSET;
766 assert(NULL == find234(ssh->channels, &i, ssh_channelfind));
767 }
768 return low + 1 + CHANNEL_NUMBER_OFFSET;
769 }
770
771 static void c_write(Ssh ssh, const char *buf, int len)
772 {
773 if ((flags & FLAG_STDERR)) {
774 int i;
775 for (i = 0; i < len; i++)
776 if (buf[i] != '\r')
777 fputc(buf[i], stderr);
778 return;
779 }
780 from_backend(ssh->frontend, 1, buf, len);
781 }
782
783 static void c_write_untrusted(Ssh ssh, const char *buf, int len)
784 {
785 int i;
786 for (i = 0; i < len; i++) {
787 if (buf[i] == '\n')
788 c_write(ssh, "\r\n", 2);
789 else if ((buf[i] & 0x60) || (buf[i] == '\r'))
790 c_write(ssh, buf + i, 1);
791 }
792 }
793
794 static void c_write_str(Ssh ssh, const char *buf)
795 {
796 c_write(ssh, buf, strlen(buf));
797 }
798
799 /*
800 * Collect incoming data in the incoming packet buffer.
801 * Decipher and verify the packet when it is completely read.
802 * Drop SSH1_MSG_DEBUG and SSH1_MSG_IGNORE packets.
803 * Update the *data and *datalen variables.
804 * Return the additional nr of bytes needed, or 0 when
805 * a complete packet is available.
806 */
807 static int ssh1_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
808 {
809 struct rdpkt1_state_tag *st = &ssh->rdpkt1_state;
810
811 crBegin(ssh->ssh1_rdpkt_crstate);
812
813 next_packet:
814
815 ssh->pktin.type = 0;
816 ssh->pktin.length = 0;
817
818 for (st->i = st->len = 0; st->i < 4; st->i++) {
819 while ((*datalen) == 0)
820 crReturn(4 - st->i);
821 st->len = (st->len << 8) + **data;
822 (*data)++, (*datalen)--;
823 }
824
825 st->pad = 8 - (st->len % 8);
826 st->biglen = st->len + st->pad;
827 ssh->pktin.length = st->len - 5;
828
829 if (ssh->pktin.maxlen < st->biglen) {
830 ssh->pktin.maxlen = st->biglen;
831 ssh->pktin.data = sresize(ssh->pktin.data, st->biglen + APIEXTRA,
832 unsigned char);
833 }
834
835 st->to_read = st->biglen;
836 st->p = ssh->pktin.data;
837 while (st->to_read > 0) {
838 st->chunk = st->to_read;
839 while ((*datalen) == 0)
840 crReturn(st->to_read);
841 if (st->chunk > (*datalen))
842 st->chunk = (*datalen);
843 memcpy(st->p, *data, st->chunk);
844 *data += st->chunk;
845 *datalen -= st->chunk;
846 st->p += st->chunk;
847 st->to_read -= st->chunk;
848 }
849
850 if (ssh->cipher && detect_attack(ssh->crcda_ctx, ssh->pktin.data,
851 st->biglen, NULL)) {
852 bombout(("Network attack (CRC compensation) detected!"));
853 crStop(0);
854 }
855
856 if (ssh->cipher)
857 ssh->cipher->decrypt(ssh->v1_cipher_ctx, ssh->pktin.data, st->biglen);
858
859 st->realcrc = crc32_compute(ssh->pktin.data, st->biglen - 4);
860 st->gotcrc = GET_32BIT(ssh->pktin.data + st->biglen - 4);
861 if (st->gotcrc != st->realcrc) {
862 bombout(("Incorrect CRC received on packet"));
863 crStop(0);
864 }
865
866 ssh->pktin.body = ssh->pktin.data + st->pad + 1;
867
868 if (ssh->v1_compressing) {
869 unsigned char *decompblk;
870 int decomplen;
871 if (!zlib_decompress_block(ssh->sc_comp_ctx,
872 ssh->pktin.body - 1, ssh->pktin.length + 1,
873 &decompblk, &decomplen)) {
874 bombout(("Zlib decompression encountered invalid data"));
875 crStop(0);
876 }
877
878 if (ssh->pktin.maxlen < st->pad + decomplen) {
879 ssh->pktin.maxlen = st->pad + decomplen;
880 ssh->pktin.data = sresize(ssh->pktin.data,
881 ssh->pktin.maxlen + APIEXTRA,
882 unsigned char);
883 ssh->pktin.body = ssh->pktin.data + st->pad + 1;
884 }
885
886 memcpy(ssh->pktin.body - 1, decompblk, decomplen);
887 sfree(decompblk);
888 ssh->pktin.length = decomplen - 1;
889 }
890
891 ssh->pktin.type = ssh->pktin.body[-1];
892
893 if (ssh->logctx)
894 log_packet(ssh->logctx,
895 PKT_INCOMING, ssh->pktin.type,
896 ssh1_pkt_type(ssh->pktin.type),
897 ssh->pktin.body, ssh->pktin.length);
898
899 if (ssh->pktin.type == SSH1_SMSG_STDOUT_DATA ||
900 ssh->pktin.type == SSH1_SMSG_STDERR_DATA ||
901 ssh->pktin.type == SSH1_MSG_DEBUG ||
902 ssh->pktin.type == SSH1_SMSG_AUTH_TIS_CHALLENGE ||
903 ssh->pktin.type == SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
904 long stringlen = GET_32BIT(ssh->pktin.body);
905 if (stringlen + 4 != ssh->pktin.length) {
906 bombout(("Received data packet with bogus string length"));
907 crStop(0);
908 }
909 }
910
911 if (ssh->pktin.type == SSH1_MSG_DEBUG) {
912 /* log debug message */
913 char buf[512];
914 int stringlen = GET_32BIT(ssh->pktin.body);
915 strcpy(buf, "Remote debug message: ");
916 if (stringlen > 480)
917 stringlen = 480;
918 memcpy(buf + 8, ssh->pktin.body + 4, stringlen);
919 buf[8 + stringlen] = '\0';
920 logevent(buf);
921 goto next_packet;
922 } else if (ssh->pktin.type == SSH1_MSG_IGNORE) {
923 /* do nothing */
924 goto next_packet;
925 }
926
927 if (ssh->pktin.type == SSH1_MSG_DISCONNECT) {
928 /* log reason code in disconnect message */
929 char buf[256];
930 unsigned msglen = GET_32BIT(ssh->pktin.body);
931 unsigned nowlen;
932 strcpy(buf, "Remote sent disconnect: ");
933 nowlen = strlen(buf);
934 if (msglen > sizeof(buf) - nowlen - 1)
935 msglen = sizeof(buf) - nowlen - 1;
936 memcpy(buf + nowlen, ssh->pktin.body + 4, msglen);
937 buf[nowlen + msglen] = '\0';
938 /* logevent(buf); (this is now done within the bombout macro) */
939 bombout(("Server sent disconnect message:\n\"%s\"", buf+nowlen));
940 crStop(0);
941 }
942
943 crFinish(0);
944 }
945
946 static int ssh2_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
947 {
948 struct rdpkt2_state_tag *st = &ssh->rdpkt2_state;
949
950 crBegin(ssh->ssh2_rdpkt_crstate);
951
952 next_packet:
953 ssh->pktin.type = 0;
954 ssh->pktin.length = 0;
955 if (ssh->sccipher)
956 st->cipherblk = ssh->sccipher->blksize;
957 else
958 st->cipherblk = 8;
959 if (st->cipherblk < 8)
960 st->cipherblk = 8;
961
962 if (ssh->pktin.maxlen < st->cipherblk) {
963 ssh->pktin.maxlen = st->cipherblk;
964 ssh->pktin.data = sresize(ssh->pktin.data, st->cipherblk + APIEXTRA,
965 unsigned char);
966 }
967
968 /*
969 * Acquire and decrypt the first block of the packet. This will
970 * contain the length and padding details.
971 */
972 for (st->i = st->len = 0; st->i < st->cipherblk; st->i++) {
973 while ((*datalen) == 0)
974 crReturn(st->cipherblk - st->i);
975 ssh->pktin.data[st->i] = *(*data)++;
976 (*datalen)--;
977 }
978
979 if (ssh->sccipher)
980 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
981 ssh->pktin.data, st->cipherblk);
982
983 /*
984 * Now get the length and padding figures.
985 */
986 st->len = GET_32BIT(ssh->pktin.data);
987 st->pad = ssh->pktin.data[4];
988
989 /*
990 * _Completely_ silly lengths should be stomped on before they
991 * do us any more damage.
992 */
993 if (st->len < 0 || st->pad < 0 || st->len + st->pad < 0) {
994 bombout(("Incoming packet was garbled on decryption"));
995 crStop(0);
996 }
997
998 /*
999 * This enables us to deduce the payload length.
1000 */
1001 st->payload = st->len - st->pad - 1;
1002
1003 ssh->pktin.length = st->payload + 5;
1004
1005 /*
1006 * So now we can work out the total packet length.
1007 */
1008 st->packetlen = st->len + 4;
1009 st->maclen = ssh->scmac ? ssh->scmac->len : 0;
1010
1011 /*
1012 * Adjust memory allocation if packet is too big.
1013 */
1014 if (ssh->pktin.maxlen < st->packetlen + st->maclen) {
1015 ssh->pktin.maxlen = st->packetlen + st->maclen;
1016 ssh->pktin.data = sresize(ssh->pktin.data,
1017 ssh->pktin.maxlen + APIEXTRA,
1018 unsigned char);
1019 }
1020
1021 /*
1022 * Read and decrypt the remainder of the packet.
1023 */
1024 for (st->i = st->cipherblk; st->i < st->packetlen + st->maclen;
1025 st->i++) {
1026 while ((*datalen) == 0)
1027 crReturn(st->packetlen + st->maclen - st->i);
1028 ssh->pktin.data[st->i] = *(*data)++;
1029 (*datalen)--;
1030 }
1031 /* Decrypt everything _except_ the MAC. */
1032 if (ssh->sccipher)
1033 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
1034 ssh->pktin.data + st->cipherblk,
1035 st->packetlen - st->cipherblk);
1036
1037 /*
1038 * Check the MAC.
1039 */
1040 if (ssh->scmac
1041 && !ssh->scmac->verify(ssh->sc_mac_ctx, ssh->pktin.data, st->len + 4,
1042 st->incoming_sequence)) {
1043 bombout(("Incorrect MAC received on packet"));
1044 crStop(0);
1045 }
1046 st->incoming_sequence++; /* whether or not we MACed */
1047
1048 /*
1049 * Decompress packet payload.
1050 */
1051 {
1052 unsigned char *newpayload;
1053 int newlen;
1054 if (ssh->sccomp &&
1055 ssh->sccomp->decompress(ssh->sc_comp_ctx,
1056 ssh->pktin.data + 5, ssh->pktin.length - 5,
1057 &newpayload, &newlen)) {
1058 if (ssh->pktin.maxlen < newlen + 5) {
1059 ssh->pktin.maxlen = newlen + 5;
1060 ssh->pktin.data = sresize(ssh->pktin.data,
1061 ssh->pktin.maxlen + APIEXTRA,
1062 unsigned char);
1063 }
1064 ssh->pktin.length = 5 + newlen;
1065 memcpy(ssh->pktin.data + 5, newpayload, newlen);
1066 sfree(newpayload);
1067 }
1068 }
1069
1070 ssh->pktin.savedpos = 6;
1071 ssh->pktin.type = ssh->pktin.data[5];
1072
1073 if (ssh->logctx)
1074 log_packet(ssh->logctx, PKT_INCOMING, ssh->pktin.type,
1075 ssh2_pkt_type(ssh->pkt_ctx, ssh->pktin.type),
1076 ssh->pktin.data+6, ssh->pktin.length-6);
1077
1078 switch (ssh->pktin.type) {
1079 /*
1080 * These packets we must handle instantly.
1081 */
1082 case SSH2_MSG_DISCONNECT:
1083 {
1084 /* log reason code in disconnect message */
1085 char *buf;
1086 int nowlen;
1087 int reason = GET_32BIT(ssh->pktin.data + 6);
1088 unsigned msglen = GET_32BIT(ssh->pktin.data + 10);
1089
1090 if (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) {
1091 buf = dupprintf("Received disconnect message (%s)",
1092 ssh2_disconnect_reasons[reason]);
1093 } else {
1094 buf = dupprintf("Received disconnect message (unknown"
1095 " type %d)", reason);
1096 }
1097 logevent(buf);
1098 sfree(buf);
1099 buf = dupprintf("Disconnection message text: %n%.*s",
1100 &nowlen, msglen, ssh->pktin.data + 14);
1101 logevent(buf);
1102 bombout(("Server sent disconnect message\ntype %d (%s):\n\"%s\"",
1103 reason,
1104 (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) ?
1105 ssh2_disconnect_reasons[reason] : "unknown",
1106 buf+nowlen));
1107 sfree(buf);
1108 crStop(0);
1109 }
1110 break;
1111 case SSH2_MSG_IGNORE:
1112 goto next_packet;
1113 case SSH2_MSG_DEBUG:
1114 {
1115 /* log the debug message */
1116 char buf[512];
1117 /* int display = ssh->pktin.body[6]; */
1118 int stringlen = GET_32BIT(ssh->pktin.data+7);
1119 int prefix;
1120 strcpy(buf, "Remote debug message: ");
1121 prefix = strlen(buf);
1122 if (stringlen > (int)(sizeof(buf)-prefix-1))
1123 stringlen = sizeof(buf)-prefix-1;
1124 memcpy(buf + prefix, ssh->pktin.data + 11, stringlen);
1125 buf[prefix + stringlen] = '\0';
1126 logevent(buf);
1127 }
1128 goto next_packet; /* FIXME: print the debug message */
1129
1130 /*
1131 * These packets we need do nothing about here.
1132 */
1133 case SSH2_MSG_UNIMPLEMENTED:
1134 case SSH2_MSG_SERVICE_REQUEST:
1135 case SSH2_MSG_SERVICE_ACCEPT:
1136 case SSH2_MSG_KEXINIT:
1137 case SSH2_MSG_NEWKEYS:
1138 case SSH2_MSG_KEXDH_INIT:
1139 case SSH2_MSG_KEXDH_REPLY:
1140 /* case SSH2_MSG_KEX_DH_GEX_REQUEST: duplicate case value */
1141 /* case SSH2_MSG_KEX_DH_GEX_GROUP: duplicate case value */
1142 case SSH2_MSG_KEX_DH_GEX_INIT:
1143 case SSH2_MSG_KEX_DH_GEX_REPLY:
1144 case SSH2_MSG_USERAUTH_REQUEST:
1145 case SSH2_MSG_USERAUTH_FAILURE:
1146 case SSH2_MSG_USERAUTH_SUCCESS:
1147 case SSH2_MSG_USERAUTH_BANNER:
1148 case SSH2_MSG_USERAUTH_PK_OK:
1149 /* case SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ: duplicate case value */
1150 /* case SSH2_MSG_USERAUTH_INFO_REQUEST: duplicate case value */
1151 case SSH2_MSG_USERAUTH_INFO_RESPONSE:
1152 case SSH2_MSG_GLOBAL_REQUEST:
1153 case SSH2_MSG_REQUEST_SUCCESS:
1154 case SSH2_MSG_REQUEST_FAILURE:
1155 case SSH2_MSG_CHANNEL_OPEN:
1156 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION:
1157 case SSH2_MSG_CHANNEL_OPEN_FAILURE:
1158 case SSH2_MSG_CHANNEL_WINDOW_ADJUST:
1159 case SSH2_MSG_CHANNEL_DATA:
1160 case SSH2_MSG_CHANNEL_EXTENDED_DATA:
1161 case SSH2_MSG_CHANNEL_EOF:
1162 case SSH2_MSG_CHANNEL_CLOSE:
1163 case SSH2_MSG_CHANNEL_REQUEST:
1164 case SSH2_MSG_CHANNEL_SUCCESS:
1165 case SSH2_MSG_CHANNEL_FAILURE:
1166 break;
1167
1168 /*
1169 * For anything else we send SSH2_MSG_UNIMPLEMENTED.
1170 */
1171 default:
1172 ssh2_pkt_init(ssh, SSH2_MSG_UNIMPLEMENTED);
1173 ssh2_pkt_adduint32(ssh, st->incoming_sequence - 1);
1174 ssh2_pkt_send(ssh);
1175 break;
1176 }
1177
1178 crFinish(0);
1179 }
1180
1181 static void ssh1_pktout_size(Ssh ssh, int len)
1182 {
1183 int pad, biglen;
1184
1185 len += 5; /* type and CRC */
1186 pad = 8 - (len % 8);
1187 biglen = len + pad;
1188
1189 ssh->pktout.length = len - 5;
1190 if (ssh->pktout.maxlen < biglen) {
1191 ssh->pktout.maxlen = biglen;
1192 #ifdef MSCRYPTOAPI
1193 /* Allocate enough buffer space for extra block
1194 * for MS CryptEncrypt() */
1195 ssh->pktout.data = sresize(ssh->pktout.data, biglen + 12,
1196 unsigned char);
1197 #else
1198 ssh->pktout.data = sresize(ssh->pktout.data, biglen + 4,
1199 unsigned char);
1200 #endif
1201 }
1202 ssh->pktout.body = ssh->pktout.data + 4 + pad + 1;
1203 }
1204
1205 static void s_wrpkt_start(Ssh ssh, int type, int len)
1206 {
1207 ssh1_pktout_size(ssh, len);
1208 ssh->pktout.type = type;
1209 }
1210
1211 static int s_wrpkt_prepare(Ssh ssh)
1212 {
1213 int pad, biglen, i;
1214 unsigned long crc;
1215 #ifdef __SC__
1216 /*
1217 * XXX various versions of SC (including 8.8.4) screw up the
1218 * register allocation in this function and use the same register
1219 * (D6) for len and as a temporary, with predictable results. The
1220 * following sledgehammer prevents this.
1221 */
1222 volatile
1223 #endif
1224 int len;
1225
1226 ssh->pktout.body[-1] = ssh->pktout.type;
1227
1228 if (ssh->logctx)
1229 log_packet(ssh->logctx, PKT_OUTGOING, ssh->pktout.type,
1230 ssh1_pkt_type(ssh->pktout.type),
1231 ssh->pktout.body, ssh->pktout.length);
1232
1233 if (ssh->v1_compressing) {
1234 unsigned char *compblk;
1235 int complen;
1236 zlib_compress_block(ssh->cs_comp_ctx,
1237 ssh->pktout.body - 1, ssh->pktout.length + 1,
1238 &compblk, &complen);
1239 ssh1_pktout_size(ssh, complen - 1);
1240 memcpy(ssh->pktout.body - 1, compblk, complen);
1241 sfree(compblk);
1242 }
1243
1244 len = ssh->pktout.length + 5; /* type and CRC */
1245 pad = 8 - (len % 8);
1246 biglen = len + pad;
1247
1248 for (i = 0; i < pad; i++)
1249 ssh->pktout.data[i + 4] = random_byte();
1250 crc = crc32_compute(ssh->pktout.data + 4, biglen - 4);
1251 PUT_32BIT(ssh->pktout.data + biglen, crc);
1252 PUT_32BIT(ssh->pktout.data, len);
1253
1254 if (ssh->cipher)
1255 ssh->cipher->encrypt(ssh->v1_cipher_ctx, ssh->pktout.data + 4, biglen);
1256
1257 return biglen + 4;
1258 }
1259
1260 static void s_wrpkt(Ssh ssh)
1261 {
1262 int len, backlog;
1263 len = s_wrpkt_prepare(ssh);
1264 backlog = sk_write(ssh->s, (char *)ssh->pktout.data, len);
1265 if (backlog > SSH_MAX_BACKLOG)
1266 ssh_throttle_all(ssh, 1, backlog);
1267 }
1268
1269 static void s_wrpkt_defer(Ssh ssh)
1270 {
1271 int len;
1272 len = s_wrpkt_prepare(ssh);
1273 if (ssh->deferred_len + len > ssh->deferred_size) {
1274 ssh->deferred_size = ssh->deferred_len + len + 128;
1275 ssh->deferred_send_data = sresize(ssh->deferred_send_data,
1276 ssh->deferred_size,
1277 unsigned char);
1278 }
1279 memcpy(ssh->deferred_send_data + ssh->deferred_len, ssh->pktout.data, len);
1280 ssh->deferred_len += len;
1281 }
1282
1283 /*
1284 * Construct a packet with the specified contents.
1285 */
1286 static void construct_packet(Ssh ssh, int pkttype, va_list ap1, va_list ap2)
1287 {
1288 unsigned char *p, *argp, argchar;
1289 unsigned long argint;
1290 int pktlen, argtype, arglen;
1291 Bignum bn;
1292
1293 pktlen = 0;
1294 while ((argtype = va_arg(ap1, int)) != PKT_END) {
1295 switch (argtype) {
1296 case PKT_INT:
1297 (void) va_arg(ap1, int);
1298 pktlen += 4;
1299 break;
1300 case PKT_CHAR:
1301 (void) va_arg(ap1, int);
1302 pktlen++;
1303 break;
1304 case PKT_DATA:
1305 (void) va_arg(ap1, unsigned char *);
1306 arglen = va_arg(ap1, int);
1307 pktlen += arglen;
1308 break;
1309 case PKT_STR:
1310 argp = va_arg(ap1, unsigned char *);
1311 arglen = strlen((char *)argp);
1312 pktlen += 4 + arglen;
1313 break;
1314 case PKT_BIGNUM:
1315 bn = va_arg(ap1, Bignum);
1316 pktlen += ssh1_bignum_length(bn);
1317 break;
1318 default:
1319 assert(0);
1320 }
1321 }
1322
1323 s_wrpkt_start(ssh, pkttype, pktlen);
1324 p = ssh->pktout.body;
1325
1326 while ((argtype = va_arg(ap2, int)) != PKT_END) {
1327 switch (argtype) {
1328 case PKT_INT:
1329 argint = va_arg(ap2, int);
1330 PUT_32BIT(p, argint);
1331 p += 4;
1332 break;
1333 case PKT_CHAR:
1334 argchar = (unsigned char) va_arg(ap2, int);
1335 *p = argchar;
1336 p++;
1337 break;
1338 case PKT_DATA:
1339 argp = va_arg(ap2, unsigned char *);
1340 arglen = va_arg(ap2, int);
1341 memcpy(p, argp, arglen);
1342 p += arglen;
1343 break;
1344 case PKT_STR:
1345 argp = va_arg(ap2, unsigned char *);
1346 arglen = strlen((char *)argp);
1347 PUT_32BIT(p, arglen);
1348 memcpy(p + 4, argp, arglen);
1349 p += 4 + arglen;
1350 break;
1351 case PKT_BIGNUM:
1352 bn = va_arg(ap2, Bignum);
1353 p += ssh1_write_bignum(p, bn);
1354 break;
1355 }
1356 }
1357 }
1358
1359 static void send_packet(Ssh ssh, int pkttype, ...)
1360 {
1361 va_list ap1, ap2;
1362 va_start(ap1, pkttype);
1363 va_start(ap2, pkttype);
1364 construct_packet(ssh, pkttype, ap1, ap2);
1365 s_wrpkt(ssh);
1366 }
1367
1368 static void defer_packet(Ssh ssh, int pkttype, ...)
1369 {
1370 va_list ap1, ap2;
1371 va_start(ap1, pkttype);
1372 va_start(ap2, pkttype);
1373 construct_packet(ssh, pkttype, ap1, ap2);
1374 s_wrpkt_defer(ssh);
1375 }
1376
1377 static int ssh_versioncmp(char *a, char *b)
1378 {
1379 char *ae, *be;
1380 unsigned long av, bv;
1381
1382 av = strtoul(a, &ae, 10);
1383 bv = strtoul(b, &be, 10);
1384 if (av != bv)
1385 return (av < bv ? -1 : +1);
1386 if (*ae == '.')
1387 ae++;
1388 if (*be == '.')
1389 be++;
1390 av = strtoul(ae, &ae, 10);
1391 bv = strtoul(be, &be, 10);
1392 if (av != bv)
1393 return (av < bv ? -1 : +1);
1394 return 0;
1395 }
1396
1397 /*
1398 * Utility routines for putting an SSH-protocol `string' and
1399 * `uint32' into a SHA state.
1400 */
1401 #include <stdio.h>
1402 static void sha_string(SHA_State * s, void *str, int len)
1403 {
1404 unsigned char lenblk[4];
1405 PUT_32BIT(lenblk, len);
1406 SHA_Bytes(s, lenblk, 4);
1407 SHA_Bytes(s, str, len);
1408 }
1409
1410 static void sha_uint32(SHA_State * s, unsigned i)
1411 {
1412 unsigned char intblk[4];
1413 PUT_32BIT(intblk, i);
1414 SHA_Bytes(s, intblk, 4);
1415 }
1416
1417 /*
1418 * SSH2 packet construction functions.
1419 */
1420 static void ssh2_pkt_ensure(Ssh ssh, int length)
1421 {
1422 if (ssh->pktout.maxlen < length) {
1423 ssh->pktout.maxlen = length + 256;
1424 ssh->pktout.data = sresize(ssh->pktout.data,
1425 ssh->pktout.maxlen + APIEXTRA,
1426 unsigned char);
1427 if (!ssh->pktout.data)
1428 fatalbox("Out of memory");
1429 }
1430 }
1431 static void ssh2_pkt_adddata(Ssh ssh, void *data, int len)
1432 {
1433 ssh->pktout.length += len;
1434 ssh2_pkt_ensure(ssh, ssh->pktout.length);
1435 memcpy(ssh->pktout.data + ssh->pktout.length - len, data, len);
1436 }
1437 static void ssh2_pkt_addbyte(Ssh ssh, unsigned char byte)
1438 {
1439 ssh2_pkt_adddata(ssh, &byte, 1);
1440 }
1441 static void ssh2_pkt_init(Ssh ssh, int pkt_type)
1442 {
1443 ssh->pktout.length = 5;
1444 ssh2_pkt_addbyte(ssh, (unsigned char) pkt_type);
1445 }
1446 static void ssh2_pkt_addbool(Ssh ssh, unsigned char value)
1447 {
1448 ssh2_pkt_adddata(ssh, &value, 1);
1449 }
1450 static void ssh2_pkt_adduint32(Ssh ssh, unsigned long value)
1451 {
1452 unsigned char x[4];
1453 PUT_32BIT(x, value);
1454 ssh2_pkt_adddata(ssh, x, 4);
1455 }
1456 static void ssh2_pkt_addstring_start(Ssh ssh)
1457 {
1458 ssh2_pkt_adduint32(ssh, 0);
1459 ssh->pktout.savedpos = ssh->pktout.length;
1460 }
1461 static void ssh2_pkt_addstring_str(Ssh ssh, char *data)
1462 {
1463 ssh2_pkt_adddata(ssh, data, strlen(data));
1464 PUT_32BIT(ssh->pktout.data + ssh->pktout.savedpos - 4,
1465 ssh->pktout.length - ssh->pktout.savedpos);
1466 }
1467 static void ssh2_pkt_addstring_data(Ssh ssh, char *data, int len)
1468 {
1469 ssh2_pkt_adddata(ssh, data, len);
1470 PUT_32BIT(ssh->pktout.data + ssh->pktout.savedpos - 4,
1471 ssh->pktout.length - ssh->pktout.savedpos);
1472 }
1473 static void ssh2_pkt_addstring(Ssh ssh, char *data)
1474 {
1475 ssh2_pkt_addstring_start(ssh);
1476 ssh2_pkt_addstring_str(ssh, data);
1477 }
1478 static unsigned char *ssh2_mpint_fmt(Bignum b, int *len)
1479 {
1480 unsigned char *p;
1481 int i, n = (bignum_bitcount(b) + 7) / 8;
1482 p = snewn(n + 1, unsigned char);
1483 if (!p)
1484 fatalbox("out of memory");
1485 p[0] = 0;
1486 for (i = 1; i <= n; i++)
1487 p[i] = bignum_byte(b, n - i);
1488 i = 0;
1489 while (i <= n && p[i] == 0 && (p[i + 1] & 0x80) == 0)
1490 i++;
1491 memmove(p, p + i, n + 1 - i);
1492 *len = n + 1 - i;
1493 return p;
1494 }
1495 static void ssh2_pkt_addmp(Ssh ssh, Bignum b)
1496 {
1497 unsigned char *p;
1498 int len;
1499 p = ssh2_mpint_fmt(b, &len);
1500 ssh2_pkt_addstring_start(ssh);
1501 ssh2_pkt_addstring_data(ssh, (char *)p, len);
1502 sfree(p);
1503 }
1504
1505 /*
1506 * Construct an SSH2 final-form packet: compress it, encrypt it,
1507 * put the MAC on it. Final packet, ready to be sent, is stored in
1508 * ssh->pktout.data. Total length is returned.
1509 */
1510 static int ssh2_pkt_construct(Ssh ssh)
1511 {
1512 int cipherblk, maclen, padding, i;
1513
1514 if (ssh->logctx)
1515 log_packet(ssh->logctx, PKT_OUTGOING, ssh->pktout.data[5],
1516 ssh2_pkt_type(ssh->pkt_ctx, ssh->pktout.data[5]),
1517 ssh->pktout.data + 6, ssh->pktout.length - 6);
1518
1519 /*
1520 * Compress packet payload.
1521 */
1522 {
1523 unsigned char *newpayload;
1524 int newlen;
1525 if (ssh->cscomp &&
1526 ssh->cscomp->compress(ssh->cs_comp_ctx, ssh->pktout.data + 5,
1527 ssh->pktout.length - 5,
1528 &newpayload, &newlen)) {
1529 ssh->pktout.length = 5;
1530 ssh2_pkt_adddata(ssh, newpayload, newlen);
1531 sfree(newpayload);
1532 }
1533 }
1534
1535 /*
1536 * Add padding. At least four bytes, and must also bring total
1537 * length (minus MAC) up to a multiple of the block size.
1538 */
1539 cipherblk = ssh->cscipher ? ssh->cscipher->blksize : 8; /* block size */
1540 cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */
1541 padding = 4;
1542 padding +=
1543 (cipherblk - (ssh->pktout.length + padding) % cipherblk) % cipherblk;
1544 maclen = ssh->csmac ? ssh->csmac->len : 0;
1545 ssh2_pkt_ensure(ssh, ssh->pktout.length + padding + maclen);
1546 ssh->pktout.data[4] = padding;
1547 for (i = 0; i < padding; i++)
1548 ssh->pktout.data[ssh->pktout.length + i] = random_byte();
1549 PUT_32BIT(ssh->pktout.data, ssh->pktout.length + padding - 4);
1550 if (ssh->csmac)
1551 ssh->csmac->generate(ssh->cs_mac_ctx, ssh->pktout.data,
1552 ssh->pktout.length + padding,
1553 ssh->v2_outgoing_sequence);
1554 ssh->v2_outgoing_sequence++; /* whether or not we MACed */
1555
1556 if (ssh->cscipher)
1557 ssh->cscipher->encrypt(ssh->cs_cipher_ctx,
1558 ssh->pktout.data, ssh->pktout.length + padding);
1559
1560 /* Ready-to-send packet starts at ssh->pktout.data. We return length. */
1561 return ssh->pktout.length + padding + maclen;
1562 }
1563
1564 /*
1565 * Construct and send an SSH2 packet immediately.
1566 */
1567 static void ssh2_pkt_send(Ssh ssh)
1568 {
1569 int len;
1570 int backlog;
1571 len = ssh2_pkt_construct(ssh);
1572 backlog = sk_write(ssh->s, (char *)ssh->pktout.data, len);
1573 if (backlog > SSH_MAX_BACKLOG)
1574 ssh_throttle_all(ssh, 1, backlog);
1575 }
1576
1577 /*
1578 * Construct an SSH2 packet and add it to a deferred data block.
1579 * Useful for sending multiple packets in a single sk_write() call,
1580 * to prevent a traffic-analysing listener from being able to work
1581 * out the length of any particular packet (such as the password
1582 * packet).
1583 *
1584 * Note that because SSH2 sequence-numbers its packets, this can
1585 * NOT be used as an m4-style `defer' allowing packets to be
1586 * constructed in one order and sent in another.
1587 */
1588 static void ssh2_pkt_defer(Ssh ssh)
1589 {
1590 int len = ssh2_pkt_construct(ssh);
1591 if (ssh->deferred_len + len > ssh->deferred_size) {
1592 ssh->deferred_size = ssh->deferred_len + len + 128;
1593 ssh->deferred_send_data = sresize(ssh->deferred_send_data,
1594 ssh->deferred_size,
1595 unsigned char);
1596 }
1597 memcpy(ssh->deferred_send_data + ssh->deferred_len, ssh->pktout.data, len);
1598 ssh->deferred_len += len;
1599 }
1600
1601 /*
1602 * Send the whole deferred data block constructed by
1603 * ssh2_pkt_defer() or SSH1's defer_packet().
1604 */
1605 static void ssh_pkt_defersend(Ssh ssh)
1606 {
1607 int backlog;
1608 backlog = sk_write(ssh->s, (char *)ssh->deferred_send_data,
1609 ssh->deferred_len);
1610 ssh->deferred_len = ssh->deferred_size = 0;
1611 sfree(ssh->deferred_send_data);
1612 ssh->deferred_send_data = NULL;
1613 if (backlog > SSH_MAX_BACKLOG)
1614 ssh_throttle_all(ssh, 1, backlog);
1615 }
1616
1617 #if 0
1618 void bndebug(char *string, Bignum b)
1619 {
1620 unsigned char *p;
1621 int i, len;
1622 p = ssh2_mpint_fmt(b, &len);
1623 debug(("%s", string));
1624 for (i = 0; i < len; i++)
1625 debug((" %02x", p[i]));
1626 debug(("\n"));
1627 sfree(p);
1628 }
1629 #endif
1630
1631 static void sha_mpint(SHA_State * s, Bignum b)
1632 {
1633 unsigned char *p;
1634 int len;
1635 p = ssh2_mpint_fmt(b, &len);
1636 sha_string(s, p, len);
1637 sfree(p);
1638 }
1639
1640 /*
1641 * SSH2 packet decode functions.
1642 */
1643 static unsigned long ssh2_pkt_getuint32(Ssh ssh)
1644 {
1645 unsigned long value;
1646 if (ssh->pktin.length - ssh->pktin.savedpos < 4)
1647 return 0; /* arrgh, no way to decline (FIXME?) */
1648 value = GET_32BIT(ssh->pktin.data + ssh->pktin.savedpos);
1649 ssh->pktin.savedpos += 4;
1650 return value;
1651 }
1652 static int ssh2_pkt_getbool(Ssh ssh)
1653 {
1654 unsigned long value;
1655 if (ssh->pktin.length - ssh->pktin.savedpos < 1)
1656 return 0; /* arrgh, no way to decline (FIXME?) */
1657 value = ssh->pktin.data[ssh->pktin.savedpos] != 0;
1658 ssh->pktin.savedpos++;
1659 return value;
1660 }
1661 static void ssh2_pkt_getstring(Ssh ssh, char **p, int *length)
1662 {
1663 int len;
1664 *p = NULL;
1665 *length = 0;
1666 if (ssh->pktin.length - ssh->pktin.savedpos < 4)
1667 return;
1668 len = GET_32BIT(ssh->pktin.data + ssh->pktin.savedpos);
1669 if (len < 0)
1670 return;
1671 *length = len;
1672 ssh->pktin.savedpos += 4;
1673 if (ssh->pktin.length - ssh->pktin.savedpos < *length)
1674 return;
1675 *p = (char *)(ssh->pktin.data + ssh->pktin.savedpos);
1676 ssh->pktin.savedpos += *length;
1677 }
1678 static Bignum ssh2_pkt_getmp(Ssh ssh)
1679 {
1680 char *p;
1681 int length;
1682 Bignum b;
1683
1684 ssh2_pkt_getstring(ssh, &p, &length);
1685 if (!p)
1686 return NULL;
1687 if (p[0] & 0x80) {
1688 bombout(("internal error: Can't handle negative mpints"));
1689 return NULL;
1690 }
1691 b = bignum_from_bytes((unsigned char *)p, length);
1692 return b;
1693 }
1694
1695 /*
1696 * Helper function to add an SSH2 signature blob to a packet.
1697 * Expects to be shown the public key blob as well as the signature
1698 * blob. Normally works just like ssh2_pkt_addstring, but will
1699 * fiddle with the signature packet if necessary for
1700 * BUG_SSH2_RSA_PADDING.
1701 */
1702 static void ssh2_add_sigblob(Ssh ssh, void *pkblob_v, int pkblob_len,
1703 void *sigblob_v, int sigblob_len)
1704 {
1705 unsigned char *pkblob = (unsigned char *)pkblob_v;
1706 unsigned char *sigblob = (unsigned char *)sigblob_v;
1707
1708 /* dmemdump(pkblob, pkblob_len); */
1709 /* dmemdump(sigblob, sigblob_len); */
1710
1711 /*
1712 * See if this is in fact an ssh-rsa signature and a buggy
1713 * server; otherwise we can just do this the easy way.
1714 */
1715 if ((ssh->remote_bugs & BUG_SSH2_RSA_PADDING) &&
1716 (GET_32BIT(pkblob) == 7 && !memcmp(pkblob+4, "ssh-rsa", 7))) {
1717 int pos, len, siglen;
1718
1719 /*
1720 * Find the byte length of the modulus.
1721 */
1722
1723 pos = 4+7; /* skip over "ssh-rsa" */
1724 pos += 4 + GET_32BIT(pkblob+pos); /* skip over exponent */
1725 len = GET_32BIT(pkblob+pos); /* find length of modulus */
1726 pos += 4; /* find modulus itself */
1727 while (len > 0 && pkblob[pos] == 0)
1728 len--, pos++;
1729 /* debug(("modulus length is %d\n", len)); */
1730
1731 /*
1732 * Now find the signature integer.
1733 */
1734 pos = 4+7; /* skip over "ssh-rsa" */
1735 siglen = GET_32BIT(sigblob+pos);
1736 /* debug(("signature length is %d\n", siglen)); */
1737
1738 if (len != siglen) {
1739 unsigned char newlen[4];
1740 ssh2_pkt_addstring_start(ssh);
1741 ssh2_pkt_addstring_data(ssh, (char *)sigblob, pos);
1742 /* dmemdump(sigblob, pos); */
1743 pos += 4; /* point to start of actual sig */
1744 PUT_32BIT(newlen, len);
1745 ssh2_pkt_addstring_data(ssh, (char *)newlen, 4);
1746 /* dmemdump(newlen, 4); */
1747 newlen[0] = 0;
1748 while (len-- > siglen) {
1749 ssh2_pkt_addstring_data(ssh, (char *)newlen, 1);
1750 /* dmemdump(newlen, 1); */
1751 }
1752 ssh2_pkt_addstring_data(ssh, (char *)(sigblob+pos), siglen);
1753 /* dmemdump(sigblob+pos, siglen); */
1754 return;
1755 }
1756
1757 /* Otherwise fall through and do it the easy way. */
1758 }
1759
1760 ssh2_pkt_addstring_start(ssh);
1761 ssh2_pkt_addstring_data(ssh, (char *)sigblob, sigblob_len);
1762 }
1763
1764 /*
1765 * Examine the remote side's version string and compare it against
1766 * a list of known buggy implementations.
1767 */
1768 static void ssh_detect_bugs(Ssh ssh, char *vstring)
1769 {
1770 char *imp; /* pointer to implementation part */
1771 imp = vstring;
1772 imp += strcspn(imp, "-");
1773 if (*imp) imp++;
1774 imp += strcspn(imp, "-");
1775 if (*imp) imp++;
1776
1777 ssh->remote_bugs = 0;
1778
1779 if (ssh->cfg.sshbug_ignore1 == FORCE_ON ||
1780 (ssh->cfg.sshbug_ignore1 == AUTO &&
1781 (!strcmp(imp, "1.2.18") || !strcmp(imp, "1.2.19") ||
1782 !strcmp(imp, "1.2.20") || !strcmp(imp, "1.2.21") ||
1783 !strcmp(imp, "1.2.22") || !strcmp(imp, "Cisco-1.25") ||
1784 !strcmp(imp, "OSU_1.4alpha3")))) {
1785 /*
1786 * These versions don't support SSH1_MSG_IGNORE, so we have
1787 * to use a different defence against password length
1788 * sniffing.
1789 */
1790 ssh->remote_bugs |= BUG_CHOKES_ON_SSH1_IGNORE;
1791 logevent("We believe remote version has SSH1 ignore bug");
1792 }
1793
1794 if (ssh->cfg.sshbug_plainpw1 == FORCE_ON ||
1795 (ssh->cfg.sshbug_plainpw1 == AUTO &&
1796 (!strcmp(imp, "Cisco-1.25") || !strcmp(imp, "OSU_1.4alpha3")))) {
1797 /*
1798 * These versions need a plain password sent; they can't
1799 * handle having a null and a random length of data after
1800 * the password.
1801 */
1802 ssh->remote_bugs |= BUG_NEEDS_SSH1_PLAIN_PASSWORD;
1803 logevent("We believe remote version needs a plain SSH1 password");
1804 }
1805
1806 if (ssh->cfg.sshbug_rsa1 == FORCE_ON ||
1807 (ssh->cfg.sshbug_rsa1 == AUTO &&
1808 (!strcmp(imp, "Cisco-1.25")))) {
1809 /*
1810 * These versions apparently have no clue whatever about
1811 * RSA authentication and will panic and die if they see
1812 * an AUTH_RSA message.
1813 */
1814 ssh->remote_bugs |= BUG_CHOKES_ON_RSA;
1815 logevent("We believe remote version can't handle RSA authentication");
1816 }
1817
1818 if (ssh->cfg.sshbug_hmac2 == FORCE_ON ||
1819 (ssh->cfg.sshbug_hmac2 == AUTO &&
1820 !wc_match("* VShell", imp) &&
1821 (wc_match("2.1.0*", imp) || wc_match("2.0.*", imp) ||
1822 wc_match("2.2.0*", imp) || wc_match("2.3.0*", imp) ||
1823 wc_match("2.1 *", imp)))) {
1824 /*
1825 * These versions have the HMAC bug.
1826 */
1827 ssh->remote_bugs |= BUG_SSH2_HMAC;
1828 logevent("We believe remote version has SSH2 HMAC bug");
1829 }
1830
1831 if (ssh->cfg.sshbug_derivekey2 == FORCE_ON ||
1832 (ssh->cfg.sshbug_derivekey2 == AUTO &&
1833 !wc_match("* VShell", imp) &&
1834 (wc_match("2.0.0*", imp) || wc_match("2.0.10*", imp) ))) {
1835 /*
1836 * These versions have the key-derivation bug (failing to
1837 * include the literal shared secret in the hashes that
1838 * generate the keys).
1839 */
1840 ssh->remote_bugs |= BUG_SSH2_DERIVEKEY;
1841 logevent("We believe remote version has SSH2 key-derivation bug");
1842 }
1843
1844 if (ssh->cfg.sshbug_rsapad2 == FORCE_ON ||
1845 (ssh->cfg.sshbug_rsapad2 == AUTO &&
1846 (wc_match("OpenSSH_2.[5-9]*", imp) ||
1847 wc_match("OpenSSH_3.[0-2]*", imp)))) {
1848 /*
1849 * These versions have the SSH2 RSA padding bug.
1850 */
1851 ssh->remote_bugs |= BUG_SSH2_RSA_PADDING;
1852 logevent("We believe remote version has SSH2 RSA padding bug");
1853 }
1854
1855 if (ssh->cfg.sshbug_pksessid2 == FORCE_ON ||
1856 (ssh->cfg.sshbug_pksessid2 == AUTO &&
1857 wc_match("OpenSSH_2.[0-2]*", imp))) {
1858 /*
1859 * These versions have the SSH2 session-ID bug in
1860 * public-key authentication.
1861 */
1862 ssh->remote_bugs |= BUG_SSH2_PK_SESSIONID;
1863 logevent("We believe remote version has SSH2 public-key-session-ID bug");
1864 }
1865
1866 if (ssh->cfg.sshbug_dhgex2 == FORCE_ON) {
1867 /*
1868 * User specified the SSH2 DH GEX bug.
1869 */
1870 ssh->remote_bugs |= BUG_SSH2_DH_GEX;
1871 logevent("We believe remote version has SSH2 DH group exchange bug");
1872 }
1873 }
1874
1875 static int do_ssh_init(Ssh ssh, unsigned char c)
1876 {
1877 struct do_ssh_init_state {
1878 int vslen;
1879 char version[10];
1880 char *vstring;
1881 int vstrsize;
1882 int i;
1883 int proto1, proto2;
1884 };
1885 crState(do_ssh_init_state);
1886
1887 crBegin(ssh->do_ssh_init_crstate);
1888
1889 /* Search for the string "SSH-" in the input. */
1890 s->i = 0;
1891 while (1) {
1892 static const int transS[] = { 1, 2, 2, 1 };
1893 static const int transH[] = { 0, 0, 3, 0 };
1894 static const int transminus[] = { 0, 0, 0, -1 };
1895 if (c == 'S')
1896 s->i = transS[s->i];
1897 else if (c == 'H')
1898 s->i = transH[s->i];
1899 else if (c == '-')
1900 s->i = transminus[s->i];
1901 else
1902 s->i = 0;
1903 if (s->i < 0)
1904 break;
1905 crReturn(1); /* get another character */
1906 }
1907
1908 s->vstrsize = 16;
1909 s->vstring = snewn(s->vstrsize, char);
1910 strcpy(s->vstring, "SSH-");
1911 s->vslen = 4;
1912 s->i = 0;
1913 while (1) {
1914 crReturn(1); /* get another char */
1915 if (s->vslen >= s->vstrsize - 1) {
1916 s->vstrsize += 16;
1917 s->vstring = sresize(s->vstring, s->vstrsize, char);
1918 }
1919 s->vstring[s->vslen++] = c;
1920 if (s->i >= 0) {
1921 if (c == '-') {
1922 s->version[s->i] = '\0';
1923 s->i = -1;
1924 } else if (s->i < sizeof(s->version) - 1)
1925 s->version[s->i++] = c;
1926 } else if (c == '\012')
1927 break;
1928 }
1929
1930 ssh->agentfwd_enabled = FALSE;
1931 ssh->rdpkt2_state.incoming_sequence = 0;
1932
1933 s->vstring[s->vslen] = 0;
1934 s->vstring[strcspn(s->vstring, "\r\n")] = '\0';/* remove EOL chars */
1935 {
1936 char *vlog;
1937 vlog = snewn(20 + s->vslen, char);
1938 sprintf(vlog, "Server version: %s", s->vstring);
1939 logevent(vlog);
1940 sfree(vlog);
1941 }
1942 ssh_detect_bugs(ssh, s->vstring);
1943
1944 /*
1945 * Decide which SSH protocol version to support.
1946 */
1947
1948 /* Anything strictly below "2.0" means protocol 1 is supported. */
1949 s->proto1 = ssh_versioncmp(s->version, "2.0") < 0;
1950 /* Anything greater or equal to "1.99" means protocol 2 is supported. */
1951 s->proto2 = ssh_versioncmp(s->version, "1.99") >= 0;
1952
1953 if (ssh->cfg.sshprot == 0 && !s->proto1) {
1954 bombout(("SSH protocol version 1 required by user but not provided by server"));
1955 crStop(0);
1956 }
1957 if (ssh->cfg.sshprot == 3 && !s->proto2) {
1958 bombout(("SSH protocol version 2 required by user but not provided by server"));
1959 crStop(0);
1960 }
1961
1962 if (s->proto2 && (ssh->cfg.sshprot >= 2 || !s->proto1)) {
1963 /*
1964 * Use v2 protocol.
1965 */
1966 char verstring[80], vlog[100];
1967 sprintf(verstring, "SSH-2.0-%s", sshver);
1968 SHA_Init(&ssh->exhashbase);
1969 /*
1970 * Hash our version string and their version string.
1971 */
1972 sha_string(&ssh->exhashbase, verstring, strlen(verstring));
1973 sha_string(&ssh->exhashbase, s->vstring, strcspn(s->vstring, "\r\n"));
1974 sprintf(vlog, "We claim version: %s", verstring);
1975 logevent(vlog);
1976 strcat(verstring, "\012");
1977 logevent("Using SSH protocol version 2");
1978 sk_write(ssh->s, verstring, strlen(verstring));
1979 ssh->protocol = ssh2_protocol;
1980 ssh->version = 2;
1981 ssh->s_rdpkt = ssh2_rdpkt;
1982 } else {
1983 /*
1984 * Use v1 protocol.
1985 */
1986 char verstring[80], vlog[100];
1987 sprintf(verstring, "SSH-%s-%s",
1988 (ssh_versioncmp(s->version, "1.5") <= 0 ? s->version : "1.5"),
1989 sshver);
1990 sprintf(vlog, "We claim version: %s", verstring);
1991 logevent(vlog);
1992 strcat(verstring, "\012");
1993
1994 logevent("Using SSH protocol version 1");
1995 sk_write(ssh->s, verstring, strlen(verstring));
1996 ssh->protocol = ssh1_protocol;
1997 ssh->version = 1;
1998 ssh->s_rdpkt = ssh1_rdpkt;
1999 }
2000 update_specials_menu(ssh->frontend);
2001 ssh->state = SSH_STATE_BEFORE_SIZE;
2002
2003 sfree(s->vstring);
2004
2005 crFinish(0);
2006 }
2007
2008 static void ssh_gotdata(Ssh ssh, unsigned char *data, int datalen)
2009 {
2010 crBegin(ssh->ssh_gotdata_crstate);
2011
2012 /*
2013 * To begin with, feed the characters one by one to the
2014 * protocol initialisation / selection function do_ssh_init().
2015 * When that returns 0, we're done with the initial greeting
2016 * exchange and can move on to packet discipline.
2017 */
2018 while (1) {
2019 int ret; /* need not be kept across crReturn */
2020 if (datalen == 0)
2021 crReturnV; /* more data please */
2022 ret = do_ssh_init(ssh, *data);
2023 data++;
2024 datalen--;
2025 if (ret == 0)
2026 break;
2027 }
2028
2029 /*
2030 * We emerge from that loop when the initial negotiation is
2031 * over and we have selected an s_rdpkt function. Now pass
2032 * everything to s_rdpkt, and then pass the resulting packets
2033 * to the proper protocol handler.
2034 */
2035 if (datalen == 0)
2036 crReturnV;
2037 while (1) {
2038 while (datalen > 0) {
2039 if (ssh->s_rdpkt(ssh, &data, &datalen) == 0) {
2040 if (ssh->state == SSH_STATE_CLOSED) {
2041 return;
2042 }
2043 ssh->protocol(ssh, NULL, 0, 1);
2044 if (ssh->state == SSH_STATE_CLOSED) {
2045 return;
2046 }
2047 }
2048 }
2049 crReturnV;
2050 }
2051 crFinishV;
2052 }
2053
2054 static void ssh_do_close(Ssh ssh)
2055 {
2056 int i;
2057 struct ssh_channel *c;
2058
2059 ssh->state = SSH_STATE_CLOSED;
2060 if (ssh->s) {
2061 sk_close(ssh->s);
2062 ssh->s = NULL;
2063 }
2064 /*
2065 * Now we must shut down any port and X forwardings going
2066 * through this connection.
2067 */
2068 if (ssh->channels) {
2069 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
2070 switch (c->type) {
2071 case CHAN_X11:
2072 x11_close(c->u.x11.s);
2073 break;
2074 case CHAN_SOCKDATA:
2075 pfd_close(c->u.pfd.s);
2076 break;
2077 }
2078 del234(ssh->channels, c);
2079 if (ssh->version == 2)
2080 bufchain_clear(&c->v.v2.outbuffer);
2081 sfree(c);
2082 }
2083 }
2084 }
2085
2086 static int ssh_closing(Plug plug, const char *error_msg, int error_code,
2087 int calling_back)
2088 {
2089 Ssh ssh = (Ssh) plug;
2090 ssh_do_close(ssh);
2091 if (error_msg) {
2092 /* A socket error has occurred. */
2093 logevent(error_msg);
2094 connection_fatal(ssh->frontend, "%s", error_msg);
2095 } else {
2096 /* Otherwise, the remote side closed the connection normally. */
2097 }
2098 return 0;
2099 }
2100
2101 static int ssh_receive(Plug plug, int urgent, char *data, int len)
2102 {
2103 Ssh ssh = (Ssh) plug;
2104 ssh_gotdata(ssh, (unsigned char *)data, len);
2105 if (ssh->state == SSH_STATE_CLOSED) {
2106 ssh_do_close(ssh);
2107 return 0;
2108 }
2109 return 1;
2110 }
2111
2112 static void ssh_sent(Plug plug, int bufsize)
2113 {
2114 Ssh ssh = (Ssh) plug;
2115 /*
2116 * If the send backlog on the SSH socket itself clears, we
2117 * should unthrottle the whole world if it was throttled.
2118 */
2119 if (bufsize < SSH_MAX_BACKLOG)
2120 ssh_throttle_all(ssh, 0, bufsize);
2121 }
2122
2123 /*
2124 * Connect to specified host and port.
2125 * Returns an error message, or NULL on success.
2126 * Also places the canonical host name into `realhost'. It must be
2127 * freed by the caller.
2128 */
2129 static const char *connect_to_host(Ssh ssh, char *host, int port,
2130 char **realhost, int nodelay)
2131 {
2132 static const struct plug_function_table fn_table = {
2133 ssh_closing,
2134 ssh_receive,
2135 ssh_sent,
2136 NULL
2137 };
2138
2139 SockAddr addr;
2140 const char *err;
2141
2142 ssh->savedhost = snewn(1 + strlen(host), char);
2143 if (!ssh->savedhost)
2144 fatalbox("Out of memory");
2145 strcpy(ssh->savedhost, host);
2146
2147 if (port < 0)
2148 port = 22; /* default ssh port */
2149 ssh->savedport = port;
2150
2151 /*
2152 * Try to find host.
2153 */
2154 logeventf(ssh, "Looking up host \"%s\"", host);
2155 addr = name_lookup(host, port, realhost, &ssh->cfg);
2156 if ((err = sk_addr_error(addr)) != NULL) {
2157 sk_addr_free(addr);
2158 return err;
2159 }
2160
2161 /*
2162 * Open socket.
2163 */
2164 {
2165 char addrbuf[100];
2166 sk_getaddr(addr, addrbuf, 100);
2167 logeventf(ssh, "Connecting to %s port %d", addrbuf, port);
2168 }
2169 ssh->fn = &fn_table;
2170 ssh->s = new_connection(addr, *realhost, port,
2171 0, 1, nodelay, (Plug) ssh, &ssh->cfg);
2172 if ((err = sk_socket_error(ssh->s)) != NULL) {
2173 ssh->s = NULL;
2174 return err;
2175 }
2176
2177 return NULL;
2178 }
2179
2180 /*
2181 * Throttle or unthrottle the SSH connection.
2182 */
2183 static void ssh1_throttle(Ssh ssh, int adjust)
2184 {
2185 int old_count = ssh->v1_throttle_count;
2186 ssh->v1_throttle_count += adjust;
2187 assert(ssh->v1_throttle_count >= 0);
2188 if (ssh->v1_throttle_count && !old_count) {
2189 sk_set_frozen(ssh->s, 1);
2190 } else if (!ssh->v1_throttle_count && old_count) {
2191 sk_set_frozen(ssh->s, 0);
2192 }
2193 }
2194
2195 /*
2196 * Throttle or unthrottle _all_ local data streams (for when sends
2197 * on the SSH connection itself back up).
2198 */
2199 static void ssh_throttle_all(Ssh ssh, int enable, int bufsize)
2200 {
2201 int i;
2202 struct ssh_channel *c;
2203
2204 if (enable == ssh->throttled_all)
2205 return;
2206 ssh->throttled_all = enable;
2207 ssh->overall_bufsize = bufsize;
2208 if (!ssh->channels)
2209 return;
2210 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
2211 switch (c->type) {
2212 case CHAN_MAINSESSION:
2213 /*
2214 * This is treated separately, outside the switch.
2215 */
2216 break;
2217 case CHAN_X11:
2218 x11_override_throttle(c->u.x11.s, enable);
2219 break;
2220 case CHAN_AGENT:
2221 /* Agent channels require no buffer management. */
2222 break;
2223 case CHAN_SOCKDATA:
2224 pfd_override_throttle(c->u.pfd.s, enable);
2225 break;
2226 }
2227 }
2228 }
2229
2230 /*
2231 * Username and password input, abstracted off into routines
2232 * reusable in several places - even between SSH1 and SSH2.
2233 */
2234
2235 /* Set up a username or password input loop on a given buffer. */
2236 static void setup_userpass_input(Ssh ssh, char *buffer, int buflen, int echo)
2237 {
2238 ssh->userpass_input_buffer = buffer;
2239 ssh->userpass_input_buflen = buflen;
2240 ssh->userpass_input_bufpos = 0;
2241 ssh->userpass_input_echo = echo;
2242 }
2243
2244 /*
2245 * Process some terminal data in the course of username/password
2246 * input. Returns >0 for success (line of input returned in
2247 * buffer), <0 for failure (user hit ^C/^D, bomb out and exit), 0
2248 * for inconclusive (keep waiting for more input please).
2249 */
2250 static int process_userpass_input(Ssh ssh, unsigned char *in, int inlen)
2251 {
2252 char c;
2253
2254 while (inlen--) {
2255 switch (c = *in++) {
2256 case 10:
2257 case 13:
2258 ssh->userpass_input_buffer[ssh->userpass_input_bufpos] = 0;
2259 ssh->userpass_input_buffer[ssh->userpass_input_buflen-1] = 0;
2260 return +1;
2261 break;
2262 case 8:
2263 case 127:
2264 if (ssh->userpass_input_bufpos > 0) {
2265 if (ssh->userpass_input_echo)
2266 c_write_str(ssh, "\b \b");
2267 ssh->userpass_input_bufpos--;
2268 }
2269 break;
2270 case 21:
2271 case 27:
2272 while (ssh->userpass_input_bufpos > 0) {
2273 if (ssh->userpass_input_echo)
2274 c_write_str(ssh, "\b \b");
2275 ssh->userpass_input_bufpos--;
2276 }
2277 break;
2278 case 3:
2279 case 4:
2280 return -1;
2281 break;
2282 default:
2283 /*
2284 * This simplistic check for printability is disabled
2285 * when we're doing password input, because some people
2286 * have control characters in their passwords.o
2287 */
2288 if ((!ssh->userpass_input_echo ||
2289 (c >= ' ' && c <= '~') ||
2290 ((unsigned char) c >= 160))
2291 && ssh->userpass_input_bufpos < ssh->userpass_input_buflen-1) {
2292 ssh->userpass_input_buffer[ssh->userpass_input_bufpos++] = c;
2293 if (ssh->userpass_input_echo)
2294 c_write(ssh, &c, 1);
2295 }
2296 break;
2297 }
2298 }
2299 return 0;
2300 }
2301
2302 static void ssh_agent_callback(void *sshv, void *reply, int replylen)
2303 {
2304 Ssh ssh = (Ssh) sshv;
2305
2306 ssh->agent_response = reply;
2307 ssh->agent_response_len = replylen;
2308
2309 if (ssh->version == 1)
2310 do_ssh1_login(ssh, NULL, -1, 0);
2311 else
2312 do_ssh2_authconn(ssh, NULL, -1, 0);
2313 }
2314
2315 static void ssh_agentf_callback(void *cv, void *reply, int replylen)
2316 {
2317 struct ssh_channel *c = (struct ssh_channel *)cv;
2318 Ssh ssh = c->ssh;
2319 void *sentreply = reply;
2320
2321 if (!sentreply) {
2322 /* Fake SSH_AGENT_FAILURE. */
2323 sentreply = "\0\0\0\1\5";
2324 replylen = 5;
2325 }
2326 if (ssh->version == 2) {
2327 ssh2_add_channel_data(c, sentreply, replylen);
2328 ssh2_try_send(c);
2329 } else {
2330 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
2331 PKT_INT, c->remoteid,
2332 PKT_INT, replylen,
2333 PKT_DATA, sentreply, replylen,
2334 PKT_END);
2335 }
2336 if (reply)
2337 sfree(reply);
2338 }
2339
2340 /*
2341 * Handle the key exchange and user authentication phases.
2342 */
2343 static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
2344 {
2345 int i, j;
2346 unsigned char cookie[8];
2347 struct RSAKey servkey, hostkey;
2348 struct MD5Context md5c;
2349 struct do_ssh1_login_state {
2350 int len;
2351 unsigned char *rsabuf, *keystr1, *keystr2;
2352 unsigned long supported_ciphers_mask, supported_auths_mask;
2353 int tried_publickey, tried_agent;
2354 int tis_auth_refused, ccard_auth_refused;
2355 unsigned char session_id[16];
2356 int cipher_type;
2357 char username[100];
2358 void *publickey_blob;
2359 int publickey_bloblen;
2360 char password[100];
2361 char prompt[200];
2362 int pos;
2363 char c;
2364 int pwpkt_type;
2365 unsigned char request[5], *response, *p;
2366 int responselen;
2367 int keyi, nkeys;
2368 int authed;
2369 struct RSAKey key;
2370 Bignum challenge;
2371 char *commentp;
2372 int commentlen;
2373 };
2374 crState(do_ssh1_login_state);
2375
2376 crBegin(ssh->do_ssh1_login_crstate);
2377
2378 if (!ispkt)
2379 crWaitUntil(ispkt);
2380
2381 if (ssh->pktin.type != SSH1_SMSG_PUBLIC_KEY) {
2382 bombout(("Public key packet not received"));
2383 crStop(0);
2384 }
2385
2386 logevent("Received public keys");
2387
2388 memcpy(cookie, ssh->pktin.body, 8);
2389
2390 i = makekey(ssh->pktin.body + 8, &servkey, &s->keystr1, 0);
2391 j = makekey(ssh->pktin.body + 8 + i, &hostkey, &s->keystr2, 0);
2392
2393 /*
2394 * Log the host key fingerprint.
2395 */
2396 {
2397 char logmsg[80];
2398 logevent("Host key fingerprint is:");
2399 strcpy(logmsg, " ");
2400 hostkey.comment = NULL;
2401 rsa_fingerprint(logmsg + strlen(logmsg),
2402 sizeof(logmsg) - strlen(logmsg), &hostkey);
2403 logevent(logmsg);
2404 }
2405
2406 ssh->v1_remote_protoflags = GET_32BIT(ssh->pktin.body + 8 + i + j);
2407 s->supported_ciphers_mask = GET_32BIT(ssh->pktin.body + 12 + i + j);
2408 s->supported_auths_mask = GET_32BIT(ssh->pktin.body + 16 + i + j);
2409
2410 ssh->v1_local_protoflags =
2411 ssh->v1_remote_protoflags & SSH1_PROTOFLAGS_SUPPORTED;
2412 ssh->v1_local_protoflags |= SSH1_PROTOFLAG_SCREEN_NUMBER;
2413
2414 MD5Init(&md5c);
2415 MD5Update(&md5c, s->keystr2, hostkey.bytes);
2416 MD5Update(&md5c, s->keystr1, servkey.bytes);
2417 MD5Update(&md5c, ssh->pktin.body, 8);
2418 MD5Final(s->session_id, &md5c);
2419
2420 for (i = 0; i < 32; i++)
2421 ssh->session_key[i] = random_byte();
2422
2423 s->len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes);
2424
2425 s->rsabuf = snewn(s->len, unsigned char);
2426 if (!s->rsabuf)
2427 fatalbox("Out of memory");
2428
2429 /*
2430 * Verify the host key.
2431 */
2432 {
2433 /*
2434 * First format the key into a string.
2435 */
2436 int len = rsastr_len(&hostkey);
2437 char fingerprint[100];
2438 char *keystr = snewn(len, char);
2439 if (!keystr)
2440 fatalbox("Out of memory");
2441 rsastr_fmt(keystr, &hostkey);
2442 rsa_fingerprint(fingerprint, sizeof(fingerprint), &hostkey);
2443 verify_ssh_host_key(ssh->frontend,
2444 ssh->savedhost, ssh->savedport, "rsa", keystr,
2445 fingerprint);
2446 sfree(keystr);
2447 }
2448
2449 for (i = 0; i < 32; i++) {
2450 s->rsabuf[i] = ssh->session_key[i];
2451 if (i < 16)
2452 s->rsabuf[i] ^= s->session_id[i];
2453 }
2454
2455 if (hostkey.bytes > servkey.bytes) {
2456 rsaencrypt(s->rsabuf, 32, &servkey);
2457 rsaencrypt(s->rsabuf, servkey.bytes, &hostkey);
2458 } else {
2459 rsaencrypt(s->rsabuf, 32, &hostkey);
2460 rsaencrypt(s->rsabuf, hostkey.bytes, &servkey);
2461 }
2462
2463 logevent("Encrypted session key");
2464
2465 {
2466 int cipher_chosen = 0, warn = 0;
2467 char *cipher_string = NULL;
2468 int i;
2469 for (i = 0; !cipher_chosen && i < CIPHER_MAX; i++) {
2470 int next_cipher = ssh->cfg.ssh_cipherlist[i];
2471 if (next_cipher == CIPHER_WARN) {
2472 /* If/when we choose a cipher, warn about it */
2473 warn = 1;
2474 } else if (next_cipher == CIPHER_AES) {
2475 /* XXX Probably don't need to mention this. */
2476 logevent("AES not supported in SSH1, skipping");
2477 } else {
2478 switch (next_cipher) {
2479 case CIPHER_3DES: s->cipher_type = SSH_CIPHER_3DES;
2480 cipher_string = "3DES"; break;
2481 case CIPHER_BLOWFISH: s->cipher_type = SSH_CIPHER_BLOWFISH;
2482 cipher_string = "Blowfish"; break;
2483 case CIPHER_DES: s->cipher_type = SSH_CIPHER_DES;
2484 cipher_string = "single-DES"; break;
2485 }
2486 if (s->supported_ciphers_mask & (1 << s->cipher_type))
2487 cipher_chosen = 1;
2488 }
2489 }
2490 if (!cipher_chosen) {
2491 if ((s->supported_ciphers_mask & (1 << SSH_CIPHER_3DES)) == 0)
2492 bombout(("Server violates SSH 1 protocol by not "
2493 "supporting 3DES encryption"));
2494 else
2495 /* shouldn't happen */
2496 bombout(("No supported ciphers found"));
2497 crStop(0);
2498 }
2499
2500 /* Warn about chosen cipher if necessary. */
2501 if (warn)
2502 askcipher(ssh->frontend, cipher_string, 0);
2503 }
2504
2505 switch (s->cipher_type) {
2506 case SSH_CIPHER_3DES:
2507 logevent("Using 3DES encryption");
2508 break;
2509 case SSH_CIPHER_DES:
2510 logevent("Using single-DES encryption");
2511 break;
2512 case SSH_CIPHER_BLOWFISH:
2513 logevent("Using Blowfish encryption");
2514 break;
2515 }
2516
2517 send_packet(ssh, SSH1_CMSG_SESSION_KEY,
2518 PKT_CHAR, s->cipher_type,
2519 PKT_DATA, cookie, 8,
2520 PKT_CHAR, (s->len * 8) >> 8, PKT_CHAR, (s->len * 8) & 0xFF,
2521 PKT_DATA, s->rsabuf, s->len,
2522 PKT_INT, ssh->v1_local_protoflags, PKT_END);
2523
2524 logevent("Trying to enable encryption...");
2525
2526 sfree(s->rsabuf);
2527
2528 ssh->cipher = (s->cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 :
2529 s->cipher_type == SSH_CIPHER_DES ? &ssh_des :
2530 &ssh_3des);
2531 ssh->v1_cipher_ctx = ssh->cipher->make_context();
2532 ssh->cipher->sesskey(ssh->v1_cipher_ctx, ssh->session_key);
2533 logeventf(ssh, "Initialised %s encryption", ssh->cipher->text_name);
2534
2535 ssh->crcda_ctx = crcda_make_context();
2536 logevent("Installing CRC compensation attack detector");
2537
2538 crWaitUntil(ispkt);
2539
2540 if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
2541 bombout(("Encryption not successfully enabled"));
2542 crStop(0);
2543 }
2544
2545 logevent("Successfully started encryption");
2546
2547 fflush(stdout);
2548 {
2549 if ((flags & FLAG_INTERACTIVE) && !*ssh->cfg.username) {
2550 if (ssh_get_line && !ssh_getline_pw_only) {
2551 if (!ssh_get_line("login as: ",
2552 s->username, sizeof(s->username), FALSE)) {
2553 /*
2554 * get_line failed to get a username.
2555 * Terminate.
2556 */
2557 logevent("No username provided. Abandoning session.");
2558 ssh_closing((Plug)ssh, NULL, 0, 0);
2559 crStop(1);
2560 }
2561 } else {
2562 int ret; /* need not be kept over crReturn */
2563 c_write_str(ssh, "login as: ");
2564 ssh->send_ok = 1;
2565
2566 setup_userpass_input(ssh, s->username, sizeof(s->username), 1);
2567 do {
2568 crWaitUntil(!ispkt);
2569 ret = process_userpass_input(ssh, in, inlen);
2570 } while (ret == 0);
2571 if (ret < 0)
2572 cleanup_exit(0);
2573 c_write_str(ssh, "\r\n");
2574 }
2575 } else {
2576 strncpy(s->username, ssh->cfg.username, sizeof(s->username));
2577 s->username[sizeof(s->username)-1] = '\0';
2578 }
2579
2580 send_packet(ssh, SSH1_CMSG_USER, PKT_STR, s->username, PKT_END);
2581 {
2582 char userlog[22 + sizeof(s->username)];
2583 sprintf(userlog, "Sent username \"%s\"", s->username);
2584 logevent(userlog);
2585 if (flags & FLAG_INTERACTIVE &&
2586 (!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) {
2587 strcat(userlog, "\r\n");
2588 c_write_str(ssh, userlog);
2589 }
2590 }
2591 }
2592
2593 crWaitUntil(ispkt);
2594
2595 if ((ssh->remote_bugs & BUG_CHOKES_ON_RSA)) {
2596 /* We must not attempt PK auth. Pretend we've already tried it. */
2597 s->tried_publickey = s->tried_agent = 1;
2598 } else {
2599 s->tried_publickey = s->tried_agent = 0;
2600 }
2601 s->tis_auth_refused = s->ccard_auth_refused = 0;
2602 /* Load the public half of ssh->cfg.keyfile so we notice if it's in Pageant */
2603 if (!filename_is_null(ssh->cfg.keyfile)) {
2604 if (!rsakey_pubblob(&ssh->cfg.keyfile,
2605 &s->publickey_blob, &s->publickey_bloblen))
2606 s->publickey_blob = NULL;
2607 } else
2608 s->publickey_blob = NULL;
2609
2610 while (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2611 s->pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
2612
2613 if (agent_exists() && !s->tried_agent) {
2614 /*
2615 * Attempt RSA authentication using Pageant.
2616 */
2617 void *r;
2618
2619 s->authed = FALSE;
2620 s->tried_agent = 1;
2621 logevent("Pageant is running. Requesting keys.");
2622
2623 /* Request the keys held by the agent. */
2624 PUT_32BIT(s->request, 1);
2625 s->request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES;
2626 if (!agent_query(s->request, 5, &r, &s->responselen,
2627 ssh_agent_callback, ssh)) {
2628 do {
2629 crReturn(0);
2630 if (ispkt) {
2631 bombout(("Unexpected data from server while waiting"
2632 " for agent response"));
2633 crStop(0);
2634 }
2635 } while (ispkt || inlen > 0);
2636 r = ssh->agent_response;
2637 s->responselen = ssh->agent_response_len;
2638 }
2639 s->response = (unsigned char *) r;
2640 if (s->response && s->responselen >= 5 &&
2641 s->response[4] == SSH1_AGENT_RSA_IDENTITIES_ANSWER) {
2642 s->p = s->response + 5;
2643 s->nkeys = GET_32BIT(s->p);
2644 s->p += 4;
2645 {
2646 char buf[64];
2647 sprintf(buf, "Pageant has %d SSH1 keys", s->nkeys);
2648 logevent(buf);
2649 }
2650 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
2651 {
2652 char buf[64];
2653 sprintf(buf, "Trying Pageant key #%d", s->keyi);
2654 logevent(buf);
2655 }
2656 if (s->publickey_blob &&
2657 !memcmp(s->p, s->publickey_blob,
2658 s->publickey_bloblen)) {
2659 logevent("This key matches configured key file");
2660 s->tried_publickey = 1;
2661 }
2662 s->p += 4;
2663 s->p += ssh1_read_bignum(s->p, &s->key.exponent);
2664 s->p += ssh1_read_bignum(s->p, &s->key.modulus);
2665 s->commentlen = GET_32BIT(s->p);
2666 s->p += 4;
2667 s->commentp = (char *)s->p;
2668 s->p += s->commentlen;
2669 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
2670 PKT_BIGNUM, s->key.modulus, PKT_END);
2671 crWaitUntil(ispkt);
2672 if (ssh->pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
2673 logevent("Key refused");
2674 continue;
2675 }
2676 logevent("Received RSA challenge");
2677 ssh1_read_bignum(ssh->pktin.body, &s->challenge);
2678 {
2679 char *agentreq, *q, *ret;
2680 void *vret;
2681 int len, retlen;
2682 len = 1 + 4; /* message type, bit count */
2683 len += ssh1_bignum_length(s->key.exponent);
2684 len += ssh1_bignum_length(s->key.modulus);
2685 len += ssh1_bignum_length(s->challenge);
2686 len += 16; /* session id */
2687 len += 4; /* response format */
2688 agentreq = snewn(4 + len, char);
2689 PUT_32BIT(agentreq, len);
2690 q = agentreq + 4;
2691 *q++ = SSH1_AGENTC_RSA_CHALLENGE;
2692 PUT_32BIT(q, bignum_bitcount(s->key.modulus));
2693 q += 4;
2694 q += ssh1_write_bignum(q, s->key.exponent);
2695 q += ssh1_write_bignum(q, s->key.modulus);
2696 q += ssh1_write_bignum(q, s->challenge);
2697 memcpy(q, s->session_id, 16);
2698 q += 16;
2699 PUT_32BIT(q, 1); /* response format */
2700 if (!agent_query(agentreq, len + 4, &vret, &retlen,
2701 ssh_agent_callback, ssh)) {
2702 sfree(agentreq);
2703 do {
2704 crReturn(0);
2705 if (ispkt) {
2706 bombout(("Unexpected data from server"
2707 " while waiting for agent"
2708 " response"));
2709 crStop(0);
2710 }
2711 } while (ispkt || inlen > 0);
2712 vret = ssh->agent_response;
2713 retlen = ssh->agent_response_len;
2714 } else
2715 sfree(agentreq);
2716 ret = vret;
2717 if (ret) {
2718 if (ret[4] == SSH1_AGENT_RSA_RESPONSE) {
2719 logevent("Sending Pageant's response");
2720 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
2721 PKT_DATA, ret + 5, 16,
2722 PKT_END);
2723 sfree(ret);
2724 crWaitUntil(ispkt);
2725 if (ssh->pktin.type == SSH1_SMSG_SUCCESS) {
2726 logevent
2727 ("Pageant's response accepted");
2728 if (flags & FLAG_VERBOSE) {
2729 c_write_str(ssh, "Authenticated using"
2730 " RSA key \"");
2731 c_write(ssh, s->commentp,
2732 s->commentlen);
2733 c_write_str(ssh, "\" from agent\r\n");
2734 }
2735 s->authed = TRUE;
2736 } else
2737 logevent
2738 ("Pageant's response not accepted");
2739 } else {
2740 logevent
2741 ("Pageant failed to answer challenge");
2742 sfree(ret);
2743 }
2744 } else {
2745 logevent("No reply received from Pageant");
2746 }
2747 }
2748 freebn(s->key.exponent);
2749 freebn(s->key.modulus);
2750 freebn(s->challenge);
2751 if (s->authed)
2752 break;
2753 }
2754 }
2755 if (s->authed)
2756 break;
2757 }
2758 if (!filename_is_null(ssh->cfg.keyfile) && !s->tried_publickey)
2759 s->pwpkt_type = SSH1_CMSG_AUTH_RSA;
2760
2761 if (ssh->cfg.try_tis_auth &&
2762 (s->supported_auths_mask & (1 << SSH1_AUTH_TIS)) &&
2763 !s->tis_auth_refused) {
2764 s->pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
2765 logevent("Requested TIS authentication");
2766 send_packet(ssh, SSH1_CMSG_AUTH_TIS, PKT_END);
2767 crWaitUntil(ispkt);
2768 if (ssh->pktin.type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
2769 logevent("TIS authentication declined");
2770 if (flags & FLAG_INTERACTIVE)
2771 c_write_str(ssh, "TIS authentication refused.\r\n");
2772 s->tis_auth_refused = 1;
2773 continue;
2774 } else {
2775 int challengelen = GET_32BIT(ssh->pktin.body);
2776 logevent("Received TIS challenge");
2777 if (challengelen > sizeof(s->prompt) - 1)
2778 challengelen = sizeof(s->prompt) - 1;/* prevent overrun */
2779 memcpy(s->prompt, ssh->pktin.body + 4, challengelen);
2780 /* Prompt heuristic comes from OpenSSH */
2781 strncpy(s->prompt + challengelen,
2782 memchr(s->prompt, '\n', challengelen) ?
2783 "": "\r\nResponse: ",
2784 (sizeof s->prompt) - challengelen);
2785 s->prompt[(sizeof s->prompt) - 1] = '\0';
2786 }
2787 }
2788 if (ssh->cfg.try_tis_auth &&
2789 (s->supported_auths_mask & (1 << SSH1_AUTH_CCARD)) &&
2790 !s->ccard_auth_refused) {
2791 s->pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE;
2792 logevent("Requested CryptoCard authentication");
2793 send_packet(ssh, SSH1_CMSG_AUTH_CCARD, PKT_END);
2794 crWaitUntil(ispkt);
2795 if (ssh->pktin.type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
2796 logevent("CryptoCard authentication declined");
2797 c_write_str(ssh, "CryptoCard authentication refused.\r\n");
2798 s->ccard_auth_refused = 1;
2799 continue;
2800 } else {
2801 int challengelen = GET_32BIT(ssh->pktin.body);
2802 logevent("Received CryptoCard challenge");
2803 if (challengelen > sizeof(s->prompt) - 1)
2804 challengelen = sizeof(s->prompt) - 1;/* prevent overrun */
2805 memcpy(s->prompt, ssh->pktin.body + 4, challengelen);
2806 strncpy(s->prompt + challengelen,
2807 memchr(s->prompt, '\n', challengelen) ?
2808 "" : "\r\nResponse: ",
2809 sizeof(s->prompt) - challengelen);
2810 s->prompt[sizeof(s->prompt) - 1] = '\0';
2811 }
2812 }
2813 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
2814 sprintf(s->prompt, "%.90s@%.90s's password: ",
2815 s->username, ssh->savedhost);
2816 }
2817 if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) {
2818 char *comment = NULL;
2819 int type;
2820 char msgbuf[256];
2821 if (flags & FLAG_VERBOSE)
2822 c_write_str(ssh, "Trying public key authentication.\r\n");
2823 logeventf(ssh, "Trying public key \"%s\"",
2824 filename_to_str(&ssh->cfg.keyfile));
2825 type = key_type(&ssh->cfg.keyfile);
2826 if (type != SSH_KEYTYPE_SSH1) {
2827 sprintf(msgbuf, "Key is of wrong type (%s)",
2828 key_type_to_str(type));
2829 logevent(msgbuf);
2830 c_write_str(ssh, msgbuf);
2831 c_write_str(ssh, "\r\n");
2832 s->tried_publickey = 1;
2833 continue;
2834 }
2835 if (!rsakey_encrypted(&ssh->cfg.keyfile, &comment)) {
2836 if (flags & FLAG_VERBOSE)
2837 c_write_str(ssh, "No passphrase required.\r\n");
2838 goto tryauth;
2839 }
2840 sprintf(s->prompt, "Passphrase for key \"%.100s\": ", comment);
2841 sfree(comment);
2842 }
2843
2844 /*
2845 * Show password prompt, having first obtained it via a TIS
2846 * or CryptoCard exchange if we're doing TIS or CryptoCard
2847 * authentication.
2848 */
2849 if (ssh_get_line) {
2850 if (!ssh_get_line(s->prompt, s->password,
2851 sizeof(s->password), TRUE)) {
2852 /*
2853 * get_line failed to get a password (for example
2854 * because one was supplied on the command line
2855 * which has already failed to work). Terminate.
2856 */
2857 send_packet(ssh, SSH1_MSG_DISCONNECT,
2858 PKT_STR, "No more passwords available to try",
2859 PKT_END);
2860 logevent("Unable to authenticate");
2861 connection_fatal(ssh->frontend, "Unable to authenticate");
2862 ssh_closing((Plug)ssh, NULL, 0, 0);
2863 crStop(1);
2864 }
2865 } else {
2866 /* Prompt may have come from server. We've munged it a bit, so
2867 * we know it to be zero-terminated at least once. */
2868 int ret; /* need not be saved over crReturn */
2869 c_write_untrusted(ssh, s->prompt, strlen(s->prompt));
2870 s->pos = 0;
2871
2872 setup_userpass_input(ssh, s->password, sizeof(s->password), 0);
2873 do {
2874 crWaitUntil(!ispkt);
2875 ret = process_userpass_input(ssh, in, inlen);
2876 } while (ret == 0);
2877 if (ret < 0)
2878 cleanup_exit(0);
2879 c_write_str(ssh, "\r\n");
2880 }
2881
2882 tryauth:
2883 if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) {
2884 /*
2885 * Try public key authentication with the specified
2886 * key file.
2887 */
2888 s->tried_publickey = 1;
2889
2890 {
2891 int ret = loadrsakey(&ssh->cfg.keyfile, &s->key, s->password);
2892 if (ret == 0) {
2893 c_write_str(ssh, "Couldn't load private key from ");
2894 c_write_str(ssh, filename_to_str(&ssh->cfg.keyfile));
2895 c_write_str(ssh, ".\r\n");
2896 continue; /* go and try password */
2897 }
2898 if (ret == -1) {
2899 c_write_str(ssh, "Wrong passphrase.\r\n");
2900 s->tried_publickey = 0;
2901 continue; /* try again */
2902 }
2903 }
2904
2905 /*
2906 * Send a public key attempt.
2907 */
2908 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
2909 PKT_BIGNUM, s->key.modulus, PKT_END);
2910
2911 crWaitUntil(ispkt);
2912 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2913 c_write_str(ssh, "Server refused our public key.\r\n");
2914 continue; /* go and try password */
2915 }
2916 if (ssh->pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
2917 bombout(("Bizarre response to offer of public key"));
2918 crStop(0);
2919 }
2920
2921 {
2922 int i;
2923 unsigned char buffer[32];
2924 Bignum challenge, response;
2925
2926 ssh1_read_bignum(ssh->pktin.body, &challenge);
2927 response = rsadecrypt(challenge, &s->key);
2928 freebn(s->key.private_exponent);/* burn the evidence */
2929
2930 for (i = 0; i < 32; i++) {
2931 buffer[i] = bignum_byte(response, 31 - i);
2932 }
2933
2934 MD5Init(&md5c);
2935 MD5Update(&md5c, buffer, 32);
2936 MD5Update(&md5c, s->session_id, 16);
2937 MD5Final(buffer, &md5c);
2938
2939 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
2940 PKT_DATA, buffer, 16, PKT_END);
2941
2942 freebn(challenge);
2943 freebn(response);
2944 }
2945
2946 crWaitUntil(ispkt);
2947 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2948 if (flags & FLAG_VERBOSE)
2949 c_write_str(ssh, "Failed to authenticate with"
2950 " our public key.\r\n");
2951 continue; /* go and try password */
2952 } else if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
2953 bombout(("Bizarre response to RSA authentication response"));
2954 crStop(0);
2955 }
2956
2957 break; /* we're through! */
2958 } else {
2959 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
2960 /*
2961 * Defence against traffic analysis: we send a
2962 * whole bunch of packets containing strings of
2963 * different lengths. One of these strings is the
2964 * password, in a SSH1_CMSG_AUTH_PASSWORD packet.
2965 * The others are all random data in
2966 * SSH1_MSG_IGNORE packets. This way a passive
2967 * listener can't tell which is the password, and
2968 * hence can't deduce the password length.
2969 *
2970 * Anybody with a password length greater than 16
2971 * bytes is going to have enough entropy in their
2972 * password that a listener won't find it _that_
2973 * much help to know how long it is. So what we'll
2974 * do is:
2975 *
2976 * - if password length < 16, we send 15 packets
2977 * containing string lengths 1 through 15
2978 *
2979 * - otherwise, we let N be the nearest multiple
2980 * of 8 below the password length, and send 8
2981 * packets containing string lengths N through
2982 * N+7. This won't obscure the order of
2983 * magnitude of the password length, but it will
2984 * introduce a bit of extra uncertainty.
2985 *
2986 * A few servers (the old 1.2.18 through 1.2.22)
2987 * can't deal with SSH1_MSG_IGNORE. For these
2988 * servers, we need an alternative defence. We make
2989 * use of the fact that the password is interpreted
2990 * as a C string: so we can append a NUL, then some
2991 * random data.
2992 *
2993 * One server (a Cisco one) can deal with neither
2994 * SSH1_MSG_IGNORE _nor_ a padded password string.
2995 * For this server we are left with no defences
2996 * against password length sniffing.
2997 */
2998 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE)) {
2999 /*
3000 * The server can deal with SSH1_MSG_IGNORE, so
3001 * we can use the primary defence.
3002 */
3003 int bottom, top, pwlen, i;
3004 char *randomstr;
3005
3006 pwlen = strlen(s->password);
3007 if (pwlen < 16) {
3008 bottom = 0; /* zero length passwords are OK! :-) */
3009 top = 15;
3010 } else {
3011 bottom = pwlen & ~7;
3012 top = bottom + 7;
3013 }
3014
3015 assert(pwlen >= bottom && pwlen <= top);
3016
3017 randomstr = snewn(top + 1, char);
3018
3019 for (i = bottom; i <= top; i++) {
3020 if (i == pwlen)
3021 defer_packet(ssh, s->pwpkt_type,
3022 PKT_STR, s->password, PKT_END);
3023 else {
3024 for (j = 0; j < i; j++) {
3025 do {
3026 randomstr[j] = random_byte();
3027 } while (randomstr[j] == '\0');
3028 }
3029 randomstr[i] = '\0';
3030 defer_packet(ssh, SSH1_MSG_IGNORE,
3031 PKT_STR, randomstr, PKT_END);
3032 }
3033 }
3034 logevent("Sending password with camouflage packets");
3035 ssh_pkt_defersend(ssh);
3036 }
3037 else if (!(ssh->remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) {
3038 /*
3039 * The server can't deal with SSH1_MSG_IGNORE
3040 * but can deal with padded passwords, so we
3041 * can use the secondary defence.
3042 */
3043 char string[64];
3044 char *ss;
3045 int len;
3046
3047 len = strlen(s->password);
3048 if (len < sizeof(string)) {
3049 ss = string;
3050 strcpy(string, s->password);
3051 len++; /* cover the zero byte */
3052 while (len < sizeof(string)) {
3053 string[len++] = (char) random_byte();
3054 }
3055 } else {
3056 ss = s->password;
3057 }
3058 logevent("Sending length-padded password");
3059 send_packet(ssh, s->pwpkt_type, PKT_INT, len,
3060 PKT_DATA, ss, len, PKT_END);
3061 } else {
3062 /*
3063 * The server has _both_
3064 * BUG_CHOKES_ON_SSH1_IGNORE and
3065 * BUG_NEEDS_SSH1_PLAIN_PASSWORD. There is
3066 * therefore nothing we can do.
3067 */
3068 int len;
3069 len = strlen(s->password);
3070 logevent("Sending unpadded password");
3071 send_packet(ssh, s->pwpkt_type, PKT_INT, len,
3072 PKT_DATA, s->password, len, PKT_END);
3073 }
3074 } else {
3075 send_packet(ssh, s->pwpkt_type, PKT_STR, s->password, PKT_END);
3076 }
3077 }
3078 logevent("Sent password");
3079 memset(s->password, 0, strlen(s->password));
3080 crWaitUntil(ispkt);
3081 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3082 if (flags & FLAG_VERBOSE)
3083 c_write_str(ssh, "Access denied\r\n");
3084 logevent("Authentication refused");
3085 } else if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
3086 bombout(("Strange packet received, type %d", ssh->pktin.type));
3087 crStop(0);
3088 }
3089 }
3090
3091 logevent("Authentication successful");
3092
3093 crFinish(1);
3094 }
3095
3096 void sshfwd_close(struct ssh_channel *c)
3097 {
3098 Ssh ssh = c->ssh;
3099
3100 if (ssh->state != SSH_STATE_SESSION) {
3101 assert(ssh->state == SSH_STATE_CLOSED);
3102 return;
3103 }
3104
3105 if (c && !c->closes) {
3106 /*
3107 * If the channel's remoteid is -1, we have sent
3108 * CHANNEL_OPEN for this channel, but it hasn't even been
3109 * acknowledged by the server. So we must set a close flag
3110 * on it now, and then when the server acks the channel
3111 * open, we can close it then.
3112 */
3113 if (((int)c->remoteid) != -1) {
3114 if (ssh->version == 1) {
3115 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid,
3116 PKT_END);
3117 } else {
3118 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
3119 ssh2_pkt_adduint32(ssh, c->remoteid);
3120 ssh2_pkt_send(ssh);
3121 }
3122 }
3123 c->closes = 1; /* sent MSG_CLOSE */
3124 if (c->type == CHAN_X11) {
3125 c->u.x11.s = NULL;
3126 logevent("Forwarded X11 connection terminated");
3127 } else if (c->type == CHAN_SOCKDATA ||
3128 c->type == CHAN_SOCKDATA_DORMANT) {
3129 c->u.pfd.s = NULL;
3130 logevent("Forwarded port closed");
3131 }
3132 }
3133 }
3134
3135 int sshfwd_write(struct ssh_channel *c, char *buf, int len)
3136 {
3137 Ssh ssh = c->ssh;
3138
3139 if (ssh->state != SSH_STATE_SESSION) {
3140 assert(ssh->state == SSH_STATE_CLOSED);
3141 return 0;
3142 }
3143
3144 if (ssh->version == 1) {
3145 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
3146 PKT_INT, c->remoteid,
3147 PKT_INT, len, PKT_DATA, buf, len, PKT_END);
3148 /*
3149 * In SSH1 we can return 0 here - implying that forwarded
3150 * connections are never individually throttled - because
3151 * the only circumstance that can cause throttling will be
3152 * the whole SSH connection backing up, in which case
3153 * _everything_ will be throttled as a whole.
3154 */
3155 return 0;
3156 } else {
3157 ssh2_add_channel_data(c, buf, len);
3158 return ssh2_try_send(c);
3159 }
3160 }
3161
3162 void sshfwd_unthrottle(struct ssh_channel *c, int bufsize)
3163 {
3164 Ssh ssh = c->ssh;
3165
3166 if (ssh->state != SSH_STATE_SESSION) {
3167 assert(ssh->state == SSH_STATE_CLOSED);
3168 return;
3169 }
3170
3171 if (ssh->version == 1) {
3172 if (c->v.v1.throttling && bufsize < SSH1_BUFFER_LIMIT) {
3173 c->v.v1.throttling = 0;
3174 ssh1_throttle(ssh, -1);
3175 }
3176 } else {
3177 ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
3178 }
3179 }
3180
3181 static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
3182 {
3183 crBegin(ssh->ssh1_protocol_crstate);
3184
3185 random_init();
3186
3187 while (!do_ssh1_login(ssh, in, inlen, ispkt)) {
3188 crReturnV;
3189 }
3190 if (ssh->state == SSH_STATE_CLOSED)
3191 crReturnV;
3192
3193 if (ssh->cfg.agentfwd && agent_exists()) {
3194 logevent("Requesting agent forwarding");
3195 send_packet(ssh, SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END);
3196 do {
3197 crReturnV;
3198 } while (!ispkt);
3199 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3200 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3201 bombout(("Protocol confusion"));
3202 crStopV;
3203 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3204 logevent("Agent forwarding refused");
3205 } else {
3206 logevent("Agent forwarding enabled");
3207 ssh->agentfwd_enabled = TRUE;
3208 }
3209 }
3210
3211 if (ssh->cfg.x11_forward) {
3212 char proto[20], data[64];
3213 logevent("Requesting X11 forwarding");
3214 ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
3215 data, sizeof(data), ssh->cfg.x11_auth);
3216 x11_get_real_auth(ssh->x11auth, ssh->cfg.x11_display);
3217 if (ssh->v1_local_protoflags & SSH1_PROTOFLAG_SCREEN_NUMBER) {
3218 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
3219 PKT_STR, proto, PKT_STR, data,
3220 PKT_INT, x11_get_screen_number(ssh->cfg.x11_display),
3221 PKT_END);
3222 } else {
3223 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
3224 PKT_STR, proto, PKT_STR, data, PKT_END);
3225 }
3226 do {
3227 crReturnV;
3228 } while (!ispkt);
3229 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3230 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3231 bombout(("Protocol confusion"));
3232 crStopV;
3233 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3234 logevent("X11 forwarding refused");
3235 } else {
3236 logevent("X11 forwarding enabled");
3237 ssh->X11_fwd_enabled = TRUE;
3238 }
3239 }
3240
3241 {
3242 char type;
3243 int n;
3244 int sport,dport,sserv,dserv;
3245 char sports[256], dports[256], saddr[256], host[256];
3246
3247 ssh->rportfwds = newtree234(ssh_rportcmp_ssh1);
3248 /* Add port forwardings. */
3249 ssh->portfwd_strptr = ssh->cfg.portfwd;
3250 while (*ssh->portfwd_strptr) {
3251 type = *ssh->portfwd_strptr++;
3252 saddr[0] = '\0';
3253 n = 0;
3254 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != '\t') {
3255 if (*ssh->portfwd_strptr == ':') {
3256 /*
3257 * We've seen a colon in the middle of the
3258 * source port number. This means that
3259 * everything we've seen until now is the
3260 * source _address_, so we'll move it into
3261 * saddr and start sports from the beginning
3262 * again.
3263 */
3264 ssh->portfwd_strptr++;
3265 sports[n] = '\0';
3266 strcpy(saddr, sports);
3267 n = 0;
3268 }
3269 if (n < 255) sports[n++] = *ssh->portfwd_strptr++;
3270 }
3271 sports[n] = 0;
3272 if (type != 'D') {
3273 if (*ssh->portfwd_strptr == '\t')
3274 ssh->portfwd_strptr++;
3275 n = 0;
3276 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':') {
3277 if (n < 255) host[n++] = *ssh->portfwd_strptr++;
3278 }
3279 host[n] = 0;
3280 if (*ssh->portfwd_strptr == ':')
3281 ssh->portfwd_strptr++;
3282 n = 0;
3283 while (*ssh->portfwd_strptr) {
3284 if (n < 255) dports[n++] = *ssh->portfwd_strptr++;
3285 }
3286 dports[n] = 0;
3287 ssh->portfwd_strptr++;
3288 dport = atoi(dports);
3289 dserv = 0;
3290 if (dport == 0) {
3291 dserv = 1;
3292 dport = net_service_lookup(dports);
3293 if (!dport) {
3294 logeventf(ssh, "Service lookup failed for"
3295 " destination port \"%s\"", dports);
3296 }
3297 }
3298 } else {
3299 while (*ssh->portfwd_strptr) ssh->portfwd_strptr++;
3300 dport = dserv = -1;
3301 }
3302 sport = atoi(sports);
3303 sserv = 0;
3304 if (sport == 0) {
3305 sserv = 1;
3306 sport = net_service_lookup(sports);
3307 if (!sport) {
3308 logeventf(ssh, "Service lookup failed for source"
3309 " port \"%s\"", sports);
3310 }
3311 }
3312 if (sport && dport) {
3313 if (type == 'L') {
3314 pfd_addforward(host, dport, *saddr ? saddr : NULL,
3315 sport, ssh, &ssh->cfg);
3316 logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
3317 " forwarding to %s:%.*s%.*s%d%.*s",
3318 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
3319 (int)(*saddr?1:0), ":",
3320 (int)(sserv ? strlen(sports) : 0), sports,
3321 sserv, "(", sport, sserv, ")",
3322 host,
3323 (int)(dserv ? strlen(dports) : 0), dports,
3324 dserv, "(", dport, dserv, ")");
3325 } else if (type == 'D') {
3326 pfd_addforward(NULL, -1, *saddr ? saddr : NULL,
3327 sport, ssh, &ssh->cfg);
3328 logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
3329 " doing SOCKS dynamic forwarding",
3330 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
3331 (int)(*saddr?1:0), ":",
3332 (int)(sserv ? strlen(sports) : 0), sports,
3333 sserv, "(", sport, sserv, ")");
3334 } else {
3335 struct ssh_rportfwd *pf;
3336 pf = snew(struct ssh_rportfwd);
3337 strcpy(pf->dhost, host);
3338 pf->dport = dport;
3339 if (saddr) {
3340 logeventf(ssh,
3341 "SSH1 cannot handle source address spec \"%s:%d\"; ignoring",
3342 saddr, sport);
3343 }
3344 if (add234(ssh->rportfwds, pf) != pf) {
3345 logeventf(ssh,
3346 "Duplicate remote port forwarding to %s:%d",
3347 host, dport);
3348 sfree(pf);
3349 } else {
3350 logeventf(ssh, "Requesting remote port %.*s%.*s%d%.*s"
3351 " forward to %s:%.*s%.*s%d%.*s",
3352 (int)(sserv ? strlen(sports) : 0), sports,
3353 sserv, "(", sport, sserv, ")",
3354 host,
3355 (int)(dserv ? strlen(dports) : 0), dports,
3356 dserv, "(", dport, dserv, ")");
3357 send_packet(ssh, SSH1_CMSG_PORT_FORWARD_REQUEST,
3358 PKT_INT, sport,
3359 PKT_STR, host,
3360 PKT_INT, dport,
3361 PKT_END);
3362 do {
3363 crReturnV;
3364 } while (!ispkt);
3365 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3366 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3367 bombout(("Protocol confusion"));
3368 crStopV;
3369 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3370 c_write_str(ssh, "Server refused port"
3371 " forwarding\r\n");
3372 }
3373 logevent("Remote port forwarding enabled");
3374 }
3375 }
3376 }
3377 }
3378 }
3379
3380 if (!ssh->cfg.nopty) {
3381 send_packet(ssh, SSH1_CMSG_REQUEST_PTY,
3382 PKT_STR, ssh->cfg.termtype,
3383 PKT_INT, ssh->term_height,
3384 PKT_INT, ssh->term_width,
3385 PKT_INT, 0, PKT_INT, 0, PKT_CHAR, 0, PKT_END);
3386 ssh->state = SSH_STATE_INTERMED;
3387 do {
3388 crReturnV;
3389 } while (!ispkt);
3390 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3391 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3392 bombout(("Protocol confusion"));
3393 crStopV;
3394 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3395 c_write_str(ssh, "Server refused to allocate pty\r\n");
3396 ssh->editing = ssh->echoing = 1;
3397 }
3398 logevent("Allocated pty");
3399 } else {
3400 ssh->editing = ssh->echoing = 1;
3401 }
3402
3403 if (ssh->cfg.compression) {
3404 send_packet(ssh, SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END);
3405 do {
3406 crReturnV;
3407 } while (!ispkt);
3408 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3409 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3410 bombout(("Protocol confusion"));
3411 crStopV;
3412 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3413 c_write_str(ssh, "Server refused to compress\r\n");
3414 }
3415 logevent("Started compression");
3416 ssh->v1_compressing = TRUE;
3417 ssh->cs_comp_ctx = zlib_compress_init();
3418 logevent("Initialised zlib (RFC1950) compression");
3419 ssh->sc_comp_ctx = zlib_decompress_init();
3420 logevent("Initialised zlib (RFC1950) decompression");
3421 }
3422
3423 /*
3424 * Start the shell or command.
3425 *
3426 * Special case: if the first-choice command is an SSH2
3427 * subsystem (hence not usable here) and the second choice
3428 * exists, we fall straight back to that.
3429 */
3430 {
3431 char *cmd = ssh->cfg.remote_cmd_ptr;
3432
3433 if (ssh->cfg.ssh_subsys && ssh->cfg.remote_cmd_ptr2) {
3434 cmd = ssh->cfg.remote_cmd_ptr2;
3435 ssh->fallback_cmd = TRUE;
3436 }
3437 if (*cmd)
3438 send_packet(ssh, SSH1_CMSG_EXEC_CMD, PKT_STR, cmd, PKT_END);
3439 else
3440 send_packet(ssh, SSH1_CMSG_EXEC_SHELL, PKT_END);
3441 logevent("Started session");
3442 }
3443
3444 ssh->state = SSH_STATE_SESSION;
3445 if (ssh->size_needed)
3446 ssh_size(ssh, ssh->term_width, ssh->term_height);
3447 if (ssh->eof_needed)
3448 ssh_special(ssh, TS_EOF);
3449
3450 if (ssh->ldisc)
3451 ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */
3452 ssh->send_ok = 1;
3453 ssh->channels = newtree234(ssh_channelcmp);
3454 while (1) {
3455 crReturnV;
3456 if (ispkt) {
3457 if (ssh->pktin.type == SSH1_SMSG_STDOUT_DATA ||
3458 ssh->pktin.type == SSH1_SMSG_STDERR_DATA) {
3459 long len = GET_32BIT(ssh->pktin.body);
3460 int bufsize =
3461 from_backend(ssh->frontend,
3462 ssh->pktin.type == SSH1_SMSG_STDERR_DATA,
3463 (char *)(ssh->pktin.body) + 4, len);
3464 if (!ssh->v1_stdout_throttling && bufsize > SSH1_BUFFER_LIMIT) {
3465 ssh->v1_stdout_throttling = 1;
3466 ssh1_throttle(ssh, +1);
3467 }
3468 } else if (ssh->pktin.type == SSH1_MSG_DISCONNECT) {
3469 ssh_closing((Plug)ssh, NULL, 0, 0);
3470 logevent("Received disconnect request");
3471 crStopV;
3472 } else if (ssh->pktin.type == SSH1_SMSG_X11_OPEN) {
3473 /* Remote side is trying to open a channel to talk to our
3474 * X-Server. Give them back a local channel number. */
3475 struct ssh_channel *c;
3476
3477 logevent("Received X11 connect request");
3478 /* Refuse if X11 forwarding is disabled. */
3479 if (!ssh->X11_fwd_enabled) {
3480 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3481 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
3482 logevent("Rejected X11 connect request");
3483 } else {
3484 c = snew(struct ssh_channel);
3485 c->ssh = ssh;
3486
3487 if (x11_init(&c->u.x11.s, ssh->cfg.x11_display, c,
3488 ssh->x11auth, NULL, -1, &ssh->cfg) != NULL) {
3489 logevent("opening X11 forward connection failed");
3490 sfree(c);
3491 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3492 PKT_INT, GET_32BIT(ssh->pktin.body),
3493 PKT_END);
3494 } else {
3495 logevent
3496 ("opening X11 forward connection succeeded");
3497 c->remoteid = GET_32BIT(ssh->pktin.body);
3498 c->localid = alloc_channel_id(ssh);
3499 c->closes = 0;
3500 c->v.v1.throttling = 0;
3501 c->type = CHAN_X11; /* identify channel type */
3502 add234(ssh->channels, c);
3503 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3504 PKT_INT, c->remoteid, PKT_INT,
3505 c->localid, PKT_END);
3506 logevent("Opened X11 forward channel");
3507 }
3508 }
3509 } else if (ssh->pktin.type == SSH1_SMSG_AGENT_OPEN) {
3510 /* Remote side is trying to open a channel to talk to our
3511 * agent. Give them back a local channel number. */
3512 struct ssh_channel *c;
3513
3514 /* Refuse if agent forwarding is disabled. */
3515 if (!ssh->agentfwd_enabled) {
3516 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3517 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
3518 } else {
3519 c = snew(struct ssh_channel);
3520 c->ssh = ssh;
3521 c->remoteid = GET_32BIT(ssh->pktin.body);
3522 c->localid = alloc_channel_id(ssh);
3523 c->closes = 0;
3524 c->v.v1.throttling = 0;
3525 c->type = CHAN_AGENT; /* identify channel type */
3526 c->u.a.lensofar = 0;
3527 add234(ssh->channels, c);
3528 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3529 PKT_INT, c->remoteid, PKT_INT, c->localid,
3530 PKT_END);
3531 }
3532 } else if (ssh->pktin.type == SSH1_MSG_PORT_OPEN) {
3533 /* Remote side is trying to open a channel to talk to a
3534 * forwarded port. Give them back a local channel number. */
3535 struct ssh_channel *c;
3536 struct ssh_rportfwd pf;
3537 int hostsize, port;
3538 char host[256], buf[1024];
3539 char *p, *h;
3540 const char *e;
3541 c = snew(struct ssh_channel);
3542 c->ssh = ssh;
3543
3544 hostsize = GET_32BIT(ssh->pktin.body+4);
3545 for (h = host, p = (char *)(ssh->pktin.body+8);
3546 hostsize != 0; hostsize--) {
3547 if (h+1 < host+sizeof(host))
3548 *h++ = *p;
3549 p++;
3550 }
3551 *h = 0;
3552 port = GET_32BIT(p);
3553
3554 strcpy(pf.dhost, host);
3555 pf.dport = port;
3556
3557 if (find234(ssh->rportfwds, &pf, NULL) == NULL) {
3558 sprintf(buf, "Rejected remote port open request for %s:%d",
3559 host, port);
3560 logevent(buf);
3561 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3562 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
3563 } else {
3564 sprintf(buf, "Received remote port open request for %s:%d",
3565 host, port);
3566 logevent(buf);
3567 e = pfd_newconnect(&c->u.pfd.s, host, port, c, &ssh->cfg);
3568 if (e != NULL) {
3569 char buf[256];
3570 sprintf(buf, "Port open failed: %s", e);
3571 logevent(buf);
3572 sfree(c);
3573 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3574 PKT_INT, GET_32BIT(ssh->pktin.body),
3575 PKT_END);
3576 } else {
3577 c->remoteid = GET_32BIT(ssh->pktin.body);
3578 c->localid = alloc_channel_id(ssh);
3579 c->closes = 0;
3580 c->v.v1.throttling = 0;
3581 c->type = CHAN_SOCKDATA; /* identify channel type */
3582 add234(ssh->channels, c);
3583 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3584 PKT_INT, c->remoteid, PKT_INT,
3585 c->localid, PKT_END);
3586 logevent("Forwarded port opened successfully");
3587 }
3588 }
3589
3590 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_OPEN_CONFIRMATION) {
3591 unsigned int remoteid = GET_32BIT(ssh->pktin.body);
3592 unsigned int localid = GET_32BIT(ssh->pktin.body+4);
3593 struct ssh_channel *c;
3594
3595 c = find234(ssh->channels, &remoteid, ssh_channelfind);
3596 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
3597 c->remoteid = localid;
3598 c->type = CHAN_SOCKDATA;
3599 c->v.v1.throttling = 0;
3600 pfd_confirm(c->u.pfd.s);
3601 }
3602
3603 if (c && c->closes) {
3604 /*
3605 * We have a pending close on this channel,
3606 * which we decided on before the server acked
3607 * the channel open. So now we know the
3608 * remoteid, we can close it again.
3609 */
3610 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE,
3611 PKT_INT, c->remoteid, PKT_END);
3612 }
3613
3614 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_OPEN_FAILURE) {
3615 unsigned int remoteid = GET_32BIT(ssh->pktin.body);
3616 struct ssh_channel *c;
3617
3618 c = find234(ssh->channels, &remoteid, ssh_channelfind);
3619 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
3620 logevent("Forwarded connection refused by server");
3621 pfd_close(c->u.pfd.s);
3622 del234(ssh->channels, c);
3623 sfree(c);
3624 }
3625
3626 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ||
3627 ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION) {
3628 /* Remote side closes a channel. */
3629 unsigned i = GET_32BIT(ssh->pktin.body);
3630 struct ssh_channel *c;
3631 c = find234(ssh->channels, &i, ssh_channelfind);
3632 if (c && ((int)c->remoteid) != -1) {
3633 int closetype;
3634 closetype =
3635 (ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ? 1 : 2);
3636
3637 if ((c->closes == 0) && (c->type == CHAN_X11)) {
3638 logevent("Forwarded X11 connection terminated");
3639 assert(c->u.x11.s != NULL);
3640 x11_close(c->u.x11.s);
3641 c->u.x11.s = NULL;
3642 }
3643 if ((c->closes == 0) && (c->type == CHAN_SOCKDATA)) {
3644 logevent("Forwarded port closed");
3645 assert(c->u.pfd.s != NULL);
3646 pfd_close(c->u.pfd.s);
3647 c->u.pfd.s = NULL;
3648 }
3649
3650 c->closes |= (closetype << 2); /* seen this message */
3651 if (!(c->closes & closetype)) {
3652 send_packet(ssh, ssh->pktin.type, PKT_INT, c->remoteid,
3653 PKT_END);
3654 c->closes |= closetype; /* sent it too */
3655 }
3656
3657 if (c->closes == 15) {
3658 del234(ssh->channels, c);
3659 sfree(c);
3660 }
3661 } else {
3662 bombout(("Received CHANNEL_CLOSE%s for %s channel %d\n",
3663 ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ? "" :
3664 "_CONFIRMATION", c ? "half-open" : "nonexistent",
3665 i));
3666 crStopV;
3667 }
3668 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_DATA) {
3669 /* Data sent down one of our channels. */
3670 int i = GET_32BIT(ssh->pktin.body);
3671 int len = GET_32BIT(ssh->pktin.body + 4);
3672 unsigned char *p = ssh->pktin.body + 8;
3673 struct ssh_channel *c;
3674 c = find234(ssh->channels, &i, ssh_channelfind);
3675 if (c) {
3676 int bufsize = 0;
3677 switch (c->type) {
3678 case CHAN_X11:
3679 bufsize = x11_send(c->u.x11.s, (char *)p, len);
3680 break;
3681 case CHAN_SOCKDATA:
3682 bufsize = pfd_send(c->u.pfd.s, (char *)p, len);
3683 break;
3684 case CHAN_AGENT:
3685 /* Data for an agent message. Buffer it. */
3686 while (len > 0) {
3687 if (c->u.a.lensofar < 4) {
3688 int l = min(4 - c->u.a.lensofar, len);
3689 memcpy(c->u.a.msglen + c->u.a.lensofar, p,
3690 l);
3691 p += l;
3692 len -= l;
3693 c->u.a.lensofar += l;
3694 }
3695 if (c->u.a.lensofar == 4) {
3696 c->u.a.totallen =
3697 4 + GET_32BIT(c->u.a.msglen);
3698 c->u.a.message = snewn(c->u.a.totallen,
3699 unsigned char);
3700 memcpy(c->u.a.message, c->u.a.msglen, 4);
3701 }
3702 if (c->u.a.lensofar >= 4 && len > 0) {
3703 int l =
3704 min(c->u.a.totallen - c->u.a.lensofar,
3705 len);
3706 memcpy(c->u.a.message + c->u.a.lensofar, p,
3707 l);
3708 p += l;
3709 len -= l;
3710 c->u.a.lensofar += l;
3711 }
3712 if (c->u.a.lensofar == c->u.a.totallen) {
3713 void *reply;
3714 int replylen;
3715 if (agent_query(c->u.a.message,
3716 c->u.a.totallen,
3717 &reply, &replylen,
3718 ssh_agentf_callback, c))
3719 ssh_agentf_callback(c, reply, replylen);
3720 sfree(c->u.a.message);
3721 c->u.a.lensofar = 0;
3722 }
3723 }
3724 bufsize = 0; /* agent channels never back up */
3725 break;
3726 }
3727 if (!c->v.v1.throttling && bufsize > SSH1_BUFFER_LIMIT) {
3728 c->v.v1.throttling = 1;
3729 ssh1_throttle(ssh, +1);
3730 }
3731 }
3732 } else if (ssh->pktin.type == SSH1_SMSG_SUCCESS) {
3733 /* may be from EXEC_SHELL on some servers */
3734 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3735 /* may be from EXEC_SHELL on some servers
3736 * if no pty is available or in other odd cases. Ignore */
3737 } else if (ssh->pktin.type == SSH1_SMSG_EXIT_STATUS) {
3738 char buf[100];
3739 ssh->exitcode = GET_32BIT(ssh->pktin.body);
3740 sprintf(buf, "Server sent command exit status %d",
3741 ssh->exitcode);
3742 logevent(buf);
3743 send_packet(ssh, SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
3744 /*
3745 * In case `helpful' firewalls or proxies tack
3746 * extra human-readable text on the end of the
3747 * session which we might mistake for another
3748 * encrypted packet, we close the session once
3749 * we've sent EXIT_CONFIRMATION.
3750 */
3751 ssh_closing((Plug)ssh, NULL, 0, 0);
3752 crStopV;
3753 } else {
3754 bombout(("Strange packet received: type %d", ssh->pktin.type));
3755 crStopV;
3756 }
3757 } else {
3758 while (inlen > 0) {
3759 int len = min(inlen, 512);
3760 send_packet(ssh, SSH1_CMSG_STDIN_DATA,
3761 PKT_INT, len, PKT_DATA, in, len, PKT_END);
3762 in += len;
3763 inlen -= len;
3764 }
3765 }
3766 }
3767
3768 crFinishV;
3769 }
3770
3771 /*
3772 * Utility routine for decoding comma-separated strings in KEXINIT.
3773 */
3774 static int in_commasep_string(char *needle, char *haystack, int haylen)
3775 {
3776 int needlen;
3777 if (!needle || !haystack) /* protect against null pointers */
3778 return 0;
3779 needlen = strlen(needle);
3780 while (1) {
3781 /*
3782 * Is it at the start of the string?
3783 */
3784 if (haylen >= needlen && /* haystack is long enough */
3785 !memcmp(needle, haystack, needlen) && /* initial match */
3786 (haylen == needlen || haystack[needlen] == ',')
3787 /* either , or EOS follows */
3788 )
3789 return 1;
3790 /*
3791 * If not, search for the next comma and resume after that.
3792 * If no comma found, terminate.
3793 */
3794 while (haylen > 0 && *haystack != ',')
3795 haylen--, haystack++;
3796 if (haylen == 0)
3797 return 0;
3798 haylen--, haystack++; /* skip over comma itself */
3799 }
3800 }
3801
3802 /*
3803 * SSH2 key creation method.
3804 */
3805 static void ssh2_mkkey(Ssh ssh, Bignum K, unsigned char *H,
3806 unsigned char *sessid, char chr,
3807 unsigned char *keyspace)
3808 {
3809 SHA_State s;
3810 /* First 20 bytes. */
3811 SHA_Init(&s);
3812 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
3813 sha_mpint(&s, K);
3814 SHA_Bytes(&s, H, 20);
3815 SHA_Bytes(&s, &chr, 1);
3816 SHA_Bytes(&s, sessid, 20);
3817 SHA_Final(&s, keyspace);
3818 /* Next 20 bytes. */
3819 SHA_Init(&s);
3820 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
3821 sha_mpint(&s, K);
3822 SHA_Bytes(&s, H, 20);
3823 SHA_Bytes(&s, keyspace, 20);
3824 SHA_Final(&s, keyspace + 20);
3825 }
3826
3827 /*
3828 * Handle the SSH2 transport layer.
3829 */
3830 static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
3831 {
3832 struct do_ssh2_transport_state {
3833 int nbits, pbits, warn;
3834 Bignum p, g, e, f, K;
3835 int kex_init_value, kex_reply_value;
3836 const struct ssh_mac **maclist;
3837 int nmacs;
3838 const struct ssh2_cipher *cscipher_tobe;
3839 const struct ssh2_cipher *sccipher_tobe;
3840 const struct ssh_mac *csmac_tobe;
3841 const struct ssh_mac *scmac_tobe;
3842 const struct ssh_compress *cscomp_tobe;
3843 const struct ssh_compress *sccomp_tobe;
3844 char *hostkeydata, *sigdata, *keystr, *fingerprint;
3845 int hostkeylen, siglen;
3846 void *hkey; /* actual host key */
3847 unsigned char exchange_hash[20];
3848 int n_preferred_ciphers;
3849 const struct ssh2_ciphers *preferred_ciphers[CIPHER_MAX];
3850 const struct ssh_compress *preferred_comp;
3851 int first_kex;
3852 };
3853 crState(do_ssh2_transport_state);
3854
3855 crBegin(ssh->do_ssh2_transport_crstate);
3856
3857 s->cscipher_tobe = s->sccipher_tobe = NULL;
3858 s->csmac_tobe = s->scmac_tobe = NULL;
3859 s->cscomp_tobe = s->sccomp_tobe = NULL;
3860
3861 random_init();
3862 s->first_kex = 1;
3863
3864 {
3865 int i;
3866 /*
3867 * Set up the preferred ciphers. (NULL => warn below here)
3868 */
3869 s->n_preferred_ciphers = 0;
3870 for (i = 0; i < CIPHER_MAX; i++) {
3871 switch (ssh->cfg.ssh_cipherlist[i]) {
3872 case CIPHER_BLOWFISH:
3873 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_blowfish;
3874 break;
3875 case CIPHER_DES:
3876 if (ssh->cfg.ssh2_des_cbc) {
3877 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_des;
3878 }
3879 break;
3880 case CIPHER_3DES:
3881 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_3des;
3882 break;
3883 case CIPHER_AES:
3884 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_aes;
3885 break;
3886 case CIPHER_WARN:
3887 /* Flag for later. Don't bother if it's the last in
3888 * the list. */
3889 if (i < CIPHER_MAX - 1) {
3890 s->preferred_ciphers[s->n_preferred_ciphers++] = NULL;
3891 }
3892 break;
3893 }
3894 }
3895 }
3896
3897 /*
3898 * Set up preferred compression.
3899 */
3900 if (ssh->cfg.compression)
3901 s->preferred_comp = &ssh_zlib;
3902 else
3903 s->preferred_comp = &ssh_comp_none;
3904
3905 /*
3906 * Be prepared to work around the buggy MAC problem.
3907 */
3908 if (ssh->remote_bugs & BUG_SSH2_HMAC)
3909 s->maclist = buggymacs, s->nmacs = lenof(buggymacs);
3910 else
3911 s->maclist = macs, s->nmacs = lenof(macs);
3912
3913 begin_key_exchange:
3914 {
3915 int i, j, cipherstr_started;
3916
3917 /*
3918 * Construct and send our key exchange packet.
3919 */
3920 ssh2_pkt_init(ssh, SSH2_MSG_KEXINIT);
3921 for (i = 0; i < 16; i++)
3922 ssh2_pkt_addbyte(ssh, (unsigned char) random_byte());
3923 /* List key exchange algorithms. */
3924 ssh2_pkt_addstring_start(ssh);
3925 for (i = 0; i < lenof(kex_algs); i++) {
3926 if (kex_algs[i] == &ssh_diffiehellman_gex &&
3927 (ssh->remote_bugs & BUG_SSH2_DH_GEX))
3928 continue;
3929 ssh2_pkt_addstring_str(ssh, kex_algs[i]->name);
3930 if (i < lenof(kex_algs) - 1)
3931 ssh2_pkt_addstring_str(ssh, ",");
3932 }
3933 /* List server host key algorithms. */
3934 ssh2_pkt_addstring_start(ssh);
3935 for (i = 0; i < lenof(hostkey_algs); i++) {
3936 ssh2_pkt_addstring_str(ssh, hostkey_algs[i]->name);
3937 if (i < lenof(hostkey_algs) - 1)
3938 ssh2_pkt_addstring_str(ssh, ",");
3939 }
3940 /* List client->server encryption algorithms. */
3941 ssh2_pkt_addstring_start(ssh);
3942 cipherstr_started = 0;
3943 for (i = 0; i < s->n_preferred_ciphers; i++) {
3944 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3945 if (!c) continue; /* warning flag */
3946 for (j = 0; j < c->nciphers; j++) {
3947 if (cipherstr_started)
3948 ssh2_pkt_addstring_str(ssh, ",");
3949 ssh2_pkt_addstring_str(ssh, c->list[j]->name);
3950 cipherstr_started = 1;
3951 }
3952 }
3953 /* List server->client encryption algorithms. */
3954 ssh2_pkt_addstring_start(ssh);
3955 cipherstr_started = 0;
3956 for (i = 0; i < s->n_preferred_ciphers; i++) {
3957 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3958 if (!c) continue; /* warning flag */
3959 for (j = 0; j < c->nciphers; j++) {
3960 if (cipherstr_started)
3961 ssh2_pkt_addstring_str(ssh, ",");
3962 ssh2_pkt_addstring_str(ssh, c->list[j]->name);
3963 cipherstr_started = 1;
3964 }
3965 }
3966 /* List client->server MAC algorithms. */
3967 ssh2_pkt_addstring_start(ssh);
3968 for (i = 0; i < s->nmacs; i++) {
3969 ssh2_pkt_addstring_str(ssh, s->maclist[i]->name);
3970 if (i < s->nmacs - 1)
3971 ssh2_pkt_addstring_str(ssh, ",");
3972 }
3973 /* List server->client MAC algorithms. */
3974 ssh2_pkt_addstring_start(ssh);
3975 for (i = 0; i < s->nmacs; i++) {
3976 ssh2_pkt_addstring_str(ssh, s->maclist[i]->name);
3977 if (i < s->nmacs - 1)
3978 ssh2_pkt_addstring_str(ssh, ",");
3979 }
3980 /* List client->server 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 server->client compression algorithms. */
3990 ssh2_pkt_addstring_start(ssh);
3991 for (i = 0; i < lenof(compressions) + 1; i++) {
3992 const struct ssh_compress *c =
3993 i == 0 ? s->preferred_comp : compressions[i - 1];
3994 ssh2_pkt_addstring_str(ssh, c->name);
3995 if (i < lenof(compressions))
3996 ssh2_pkt_addstring_str(ssh, ",");
3997 }
3998 /* List client->server languages. Empty list. */
3999 ssh2_pkt_addstring_start(ssh);
4000 /* List server->client languages. Empty list. */
4001 ssh2_pkt_addstring_start(ssh);
4002 /* First KEX packet does _not_ follow, because we're not that brave. */
4003 ssh2_pkt_addbool(ssh, FALSE);
4004 /* Reserved. */
4005 ssh2_pkt_adduint32(ssh, 0);
4006 }
4007
4008 ssh->exhash = ssh->exhashbase;
4009 sha_string(&ssh->exhash, ssh->pktout.data + 5, ssh->pktout.length - 5);
4010
4011 ssh2_pkt_send(ssh);
4012
4013 if (!ispkt)
4014 crWaitUntil(ispkt);
4015 if (ssh->pktin.length > 5)
4016 sha_string(&ssh->exhash, ssh->pktin.data + 5, ssh->pktin.length - 5);
4017
4018 /*
4019 * Now examine the other side's KEXINIT to see what we're up
4020 * to.
4021 */
4022 {
4023 char *str;
4024 int i, j, len;
4025
4026 if (ssh->pktin.type != SSH2_MSG_KEXINIT) {
4027 bombout(("expected key exchange packet from server"));
4028 crStop(0);
4029 }
4030 ssh->kex = NULL;
4031 ssh->hostkey = NULL;
4032 s->cscipher_tobe = NULL;
4033 s->sccipher_tobe = NULL;
4034 s->csmac_tobe = NULL;
4035 s->scmac_tobe = NULL;
4036 s->cscomp_tobe = NULL;
4037 s->sccomp_tobe = NULL;
4038 ssh->pktin.savedpos += 16; /* skip garbage cookie */
4039 ssh2_pkt_getstring(ssh, &str, &len); /* key exchange algorithms */
4040 for (i = 0; i < lenof(kex_algs); i++) {
4041 if (kex_algs[i] == &ssh_diffiehellman_gex &&
4042 (ssh->remote_bugs & BUG_SSH2_DH_GEX))
4043 continue;
4044 if (in_commasep_string(kex_algs[i]->name, str, len)) {
4045 ssh->kex = kex_algs[i];
4046 break;
4047 }
4048 }
4049 ssh2_pkt_getstring(ssh, &str, &len); /* host key algorithms */
4050 for (i = 0; i < lenof(hostkey_algs); i++) {
4051 if (in_commasep_string(hostkey_algs[i]->name, str, len)) {
4052 ssh->hostkey = hostkey_algs[i];
4053 break;
4054 }
4055 }
4056 ssh2_pkt_getstring(ssh, &str, &len); /* client->server cipher */
4057 s->warn = 0;
4058 for (i = 0; i < s->n_preferred_ciphers; i++) {
4059 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
4060 if (!c) {
4061 s->warn = 1;
4062 } else {
4063 for (j = 0; j < c->nciphers; j++) {
4064 if (in_commasep_string(c->list[j]->name, str, len)) {
4065 s->cscipher_tobe = c->list[j];
4066 break;
4067 }
4068 }
4069 }
4070 if (s->cscipher_tobe) {
4071 if (s->warn)
4072 askcipher(ssh->frontend, s->cscipher_tobe->name, 1);
4073 break;
4074 }
4075 }
4076 if (!s->cscipher_tobe) {
4077 bombout(("Couldn't agree a client-to-server cipher (available: %s)",
4078 str ? str : "(null)"));
4079 crStop(0);
4080 }
4081
4082 ssh2_pkt_getstring(ssh, &str, &len); /* server->client cipher */
4083 s->warn = 0;
4084 for (i = 0; i < s->n_preferred_ciphers; i++) {
4085 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
4086 if (!c) {
4087 s->warn = 1;
4088 } else {
4089 for (j = 0; j < c->nciphers; j++) {
4090 if (in_commasep_string(c->list[j]->name, str, len)) {
4091 s->sccipher_tobe = c->list[j];
4092 break;
4093 }
4094 }
4095 }
4096 if (s->sccipher_tobe) {
4097 if (s->warn)
4098 askcipher(ssh->frontend, s->sccipher_tobe->name, 2);
4099 break;
4100 }
4101 }
4102 if (!s->sccipher_tobe) {
4103 bombout(("Couldn't agree a server-to-client cipher (available: %s)",
4104 str ? str : "(null)"));
4105 crStop(0);
4106 }
4107
4108 ssh2_pkt_getstring(ssh, &str, &len); /* client->server mac */
4109 for (i = 0; i < s->nmacs; i++) {
4110 if (in_commasep_string(s->maclist[i]->name, str, len)) {
4111 s->csmac_tobe = s->maclist[i];
4112 break;
4113 }
4114 }
4115 ssh2_pkt_getstring(ssh, &str, &len); /* server->client mac */
4116 for (i = 0; i < s->nmacs; i++) {
4117 if (in_commasep_string(s->maclist[i]->name, str, len)) {
4118 s->scmac_tobe = s->maclist[i];
4119 break;
4120 }
4121 }
4122 ssh2_pkt_getstring(ssh, &str, &len); /* client->server 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->cscomp_tobe = c;
4128 break;
4129 }
4130 }
4131 ssh2_pkt_getstring(ssh, &str, &len); /* server->client compression */
4132 for (i = 0; i < lenof(compressions) + 1; i++) {
4133 const struct ssh_compress *c =
4134 i == 0 ? s->preferred_comp : compressions[i - 1];
4135 if (in_commasep_string(c->name, str, len)) {
4136 s->sccomp_tobe = c;
4137 break;
4138 }
4139 }
4140 }
4141
4142 /*
4143 * Work out the number of bits of key we will need from the key
4144 * exchange. We start with the maximum key length of either
4145 * cipher...
4146 */
4147 {
4148 int csbits, scbits;
4149
4150 csbits = s->cscipher_tobe->keylen;
4151 scbits = s->sccipher_tobe->keylen;
4152 s->nbits = (csbits > scbits ? csbits : scbits);
4153 }
4154 /* The keys only have 160-bit entropy, since they're based on
4155 * a SHA-1 hash. So cap the key size at 160 bits. */
4156 if (s->nbits > 160)
4157 s->nbits = 160;
4158
4159 /*
4160 * If we're doing Diffie-Hellman group exchange, start by
4161 * requesting a group.
4162 */
4163 if (ssh->kex == &ssh_diffiehellman_gex) {
4164 logevent("Doing Diffie-Hellman group exchange");
4165 ssh->pkt_ctx |= SSH2_PKTCTX_DHGEX;
4166 /*
4167 * Work out how big a DH group we will need to allow that
4168 * much data.
4169 */
4170 s->pbits = 512 << ((s->nbits - 1) / 64);
4171 ssh2_pkt_init(ssh, SSH2_MSG_KEX_DH_GEX_REQUEST);
4172 ssh2_pkt_adduint32(ssh, s->pbits);
4173 ssh2_pkt_send(ssh);
4174
4175 crWaitUntil(ispkt);
4176 if (ssh->pktin.type != SSH2_MSG_KEX_DH_GEX_GROUP) {
4177 bombout(("expected key exchange group packet from server"));
4178 crStop(0);
4179 }
4180 s->p = ssh2_pkt_getmp(ssh);
4181 s->g = ssh2_pkt_getmp(ssh);
4182 ssh->kex_ctx = dh_setup_group(s->p, s->g);
4183 s->kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT;
4184 s->kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY;
4185 } else {
4186 ssh->pkt_ctx |= SSH2_PKTCTX_DHGROUP1;
4187 ssh->kex_ctx = dh_setup_group1();
4188 s->kex_init_value = SSH2_MSG_KEXDH_INIT;
4189 s->kex_reply_value = SSH2_MSG_KEXDH_REPLY;
4190 }
4191
4192 logevent("Doing Diffie-Hellman key exchange");
4193 /*
4194 * Now generate and send e for Diffie-Hellman.
4195 */
4196 s->e = dh_create_e(ssh->kex_ctx, s->nbits * 2);
4197 ssh2_pkt_init(ssh, s->kex_init_value);
4198 ssh2_pkt_addmp(ssh, s->e);
4199 ssh2_pkt_send(ssh);
4200
4201 crWaitUntil(ispkt);
4202 if (ssh->pktin.type != s->kex_reply_value) {
4203 bombout(("expected key exchange reply packet from server"));
4204 crStop(0);
4205 }
4206 ssh2_pkt_getstring(ssh, &s->hostkeydata, &s->hostkeylen);
4207 s->f = ssh2_pkt_getmp(ssh);
4208 ssh2_pkt_getstring(ssh, &s->sigdata, &s->siglen);
4209
4210 s->K = dh_find_K(ssh->kex_ctx, s->f);
4211
4212 sha_string(&ssh->exhash, s->hostkeydata, s->hostkeylen);
4213 if (ssh->kex == &ssh_diffiehellman_gex) {
4214 sha_uint32(&ssh->exhash, s->pbits);
4215 sha_mpint(&ssh->exhash, s->p);
4216 sha_mpint(&ssh->exhash, s->g);
4217 }
4218 sha_mpint(&ssh->exhash, s->e);
4219 sha_mpint(&ssh->exhash, s->f);
4220 sha_mpint(&ssh->exhash, s->K);
4221 SHA_Final(&ssh->exhash, s->exchange_hash);
4222
4223 dh_cleanup(ssh->kex_ctx);
4224 ssh->kex_ctx = NULL;
4225
4226 #if 0
4227 debug(("Exchange hash is:\n"));
4228 dmemdump(s->exchange_hash, 20);
4229 #endif
4230
4231 s->hkey = ssh->hostkey->newkey(s->hostkeydata, s->hostkeylen);
4232 if (!s->hkey ||
4233 !ssh->hostkey->verifysig(s->hkey, s->sigdata, s->siglen,
4234 (char *)s->exchange_hash, 20)) {
4235 bombout(("Server's host key did not match the signature supplied"));
4236 crStop(0);
4237 }
4238
4239 /*
4240 * Authenticate remote host: verify host key. (We've already
4241 * checked the signature of the exchange hash.)
4242 */
4243 s->keystr = ssh->hostkey->fmtkey(s->hkey);
4244 s->fingerprint = ssh->hostkey->fingerprint(s->hkey);
4245 verify_ssh_host_key(ssh->frontend,
4246 ssh->savedhost, ssh->savedport, ssh->hostkey->keytype,
4247 s->keystr, s->fingerprint);
4248 if (s->first_kex) { /* don't bother logging this in rekeys */
4249 logevent("Host key fingerprint is:");
4250 logevent(s->fingerprint);
4251 }
4252 sfree(s->fingerprint);
4253 sfree(s->keystr);
4254 ssh->hostkey->freekey(s->hkey);
4255
4256 /*
4257 * Send SSH2_MSG_NEWKEYS.
4258 */
4259 ssh2_pkt_init(ssh, SSH2_MSG_NEWKEYS);
4260 ssh2_pkt_send(ssh);
4261
4262 /*
4263 * Expect SSH2_MSG_NEWKEYS from server.
4264 */
4265 crWaitUntil(ispkt);
4266 if (ssh->pktin.type != SSH2_MSG_NEWKEYS) {
4267 bombout(("expected new-keys packet from server"));
4268 crStop(0);
4269 }
4270
4271 /*
4272 * Create and initialise session keys.
4273 */
4274 if (ssh->cs_cipher_ctx)
4275 ssh->cscipher->free_context(ssh->cs_cipher_ctx);
4276 ssh->cscipher = s->cscipher_tobe;
4277 ssh->cs_cipher_ctx = ssh->cscipher->make_context();
4278
4279 if (ssh->sc_cipher_ctx)
4280 ssh->sccipher->free_context(ssh->sc_cipher_ctx);
4281 ssh->sccipher = s->sccipher_tobe;
4282 ssh->sc_cipher_ctx = ssh->sccipher->make_context();
4283
4284 if (ssh->cs_mac_ctx)
4285 ssh->csmac->free_context(ssh->cs_mac_ctx);
4286 ssh->csmac = s->csmac_tobe;
4287 ssh->cs_mac_ctx = ssh->csmac->make_context();
4288
4289 if (ssh->sc_mac_ctx)
4290 ssh->scmac->free_context(ssh->sc_mac_ctx);
4291 ssh->scmac = s->scmac_tobe;
4292 ssh->sc_mac_ctx = ssh->scmac->make_context();
4293
4294 if (ssh->cs_comp_ctx)
4295 ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
4296 ssh->cscomp = s->cscomp_tobe;
4297 ssh->cs_comp_ctx = ssh->cscomp->compress_init();
4298
4299 if (ssh->sc_comp_ctx)
4300 ssh->sccomp->decompress_cleanup(ssh->sc_comp_ctx);
4301 ssh->sccomp = s->sccomp_tobe;
4302 ssh->sc_comp_ctx = ssh->sccomp->decompress_init();
4303
4304 /*
4305 * Set IVs after keys. Here we use the exchange hash from the
4306 * _first_ key exchange.
4307 */
4308 {
4309 unsigned char keyspace[40];
4310 if (s->first_kex)
4311 memcpy(ssh->v2_session_id, s->exchange_hash,
4312 sizeof(s->exchange_hash));
4313 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'C',keyspace);
4314 ssh->cscipher->setkey(ssh->cs_cipher_ctx, keyspace);
4315 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'D',keyspace);
4316 ssh->sccipher->setkey(ssh->sc_cipher_ctx, keyspace);
4317 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'A',keyspace);
4318 ssh->cscipher->setiv(ssh->cs_cipher_ctx, keyspace);
4319 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'B',keyspace);
4320 ssh->sccipher->setiv(ssh->sc_cipher_ctx, keyspace);
4321 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'E',keyspace);
4322 ssh->csmac->setkey(ssh->cs_mac_ctx, keyspace);
4323 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'F',keyspace);
4324 ssh->scmac->setkey(ssh->sc_mac_ctx, keyspace);
4325 }
4326 logeventf(ssh, "Initialised %.200s client->server encryption",
4327 ssh->cscipher->text_name);
4328 logeventf(ssh, "Initialised %.200s server->client encryption",
4329 ssh->sccipher->text_name);
4330 if (ssh->cscomp->text_name)
4331 logeventf(ssh, "Initialised %s compression",
4332 ssh->cscomp->text_name);
4333 if (ssh->sccomp->text_name)
4334 logeventf(ssh, "Initialised %s decompression",
4335 ssh->sccomp->text_name);
4336
4337 /*
4338 * If this is the first key exchange phase, we must pass the
4339 * SSH2_MSG_NEWKEYS packet to the next layer, not because it
4340 * wants to see it but because it will need time to initialise
4341 * itself before it sees an actual packet. In subsequent key
4342 * exchange phases, we don't pass SSH2_MSG_NEWKEYS on, because
4343 * it would only confuse the layer above.
4344 */
4345 if (!s->first_kex) {
4346 crReturn(0);
4347 }
4348 s->first_kex = 0;
4349
4350 /*
4351 * Now we're encrypting. Begin returning 1 to the protocol main
4352 * function so that other things can run on top of the
4353 * transport. If we ever see a KEXINIT, we must go back to the
4354 * start.
4355 */
4356 while (!(ispkt && ssh->pktin.type == SSH2_MSG_KEXINIT)) {
4357 crReturn(1);
4358 }
4359 logevent("Server initiated key re-exchange");
4360 goto begin_key_exchange;
4361
4362 crFinish(1);
4363 }
4364
4365 /*
4366 * Add data to an SSH2 channel output buffer.
4367 */
4368 static void ssh2_add_channel_data(struct ssh_channel *c, char *buf,
4369 int len)
4370 {
4371 bufchain_add(&c->v.v2.outbuffer, buf, len);
4372 }
4373
4374 /*
4375 * Attempt to send data on an SSH2 channel.
4376 */
4377 static int ssh2_try_send(struct ssh_channel *c)
4378 {
4379 Ssh ssh = c->ssh;
4380
4381 while (c->v.v2.remwindow > 0 && bufchain_size(&c->v.v2.outbuffer) > 0) {
4382 int len;
4383 void *data;
4384 bufchain_prefix(&c->v.v2.outbuffer, &data, &len);
4385 if ((unsigned)len > c->v.v2.remwindow)
4386 len = c->v.v2.remwindow;
4387 if ((unsigned)len > c->v.v2.remmaxpkt)
4388 len = c->v.v2.remmaxpkt;
4389 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_DATA);
4390 ssh2_pkt_adduint32(ssh, c->remoteid);
4391 ssh2_pkt_addstring_start(ssh);
4392 ssh2_pkt_addstring_data(ssh, data, len);
4393 ssh2_pkt_send(ssh);
4394 bufchain_consume(&c->v.v2.outbuffer, len);
4395 c->v.v2.remwindow -= len;
4396 }
4397
4398 /*
4399 * After having sent as much data as we can, return the amount
4400 * still buffered.
4401 */
4402 return bufchain_size(&c->v.v2.outbuffer);
4403 }
4404
4405 /*
4406 * Potentially enlarge the window on an SSH2 channel.
4407 */
4408 static void ssh2_set_window(struct ssh_channel *c, unsigned newwin)
4409 {
4410 Ssh ssh = c->ssh;
4411
4412 /*
4413 * Never send WINDOW_ADJUST for a channel that the remote side
4414 * already thinks it's closed; there's no point, since it won't
4415 * be sending any more data anyway.
4416 */
4417 if (c->closes != 0)
4418 return;
4419
4420 if (newwin > c->v.v2.locwindow) {
4421 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST);
4422 ssh2_pkt_adduint32(ssh, c->remoteid);
4423 ssh2_pkt_adduint32(ssh, newwin - c->v.v2.locwindow);
4424 ssh2_pkt_send(ssh);
4425 c->v.v2.locwindow = newwin;
4426 }
4427 }
4428
4429 /*
4430 * Handle the SSH2 userauth and connection layers.
4431 */
4432 static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
4433 {
4434 struct do_ssh2_authconn_state {
4435 enum {
4436 AUTH_INVALID, AUTH_PUBLICKEY_AGENT, AUTH_PUBLICKEY_FILE,
4437 AUTH_PASSWORD,
4438 AUTH_KEYBOARD_INTERACTIVE
4439 } method;
4440 enum {
4441 AUTH_TYPE_NONE,
4442 AUTH_TYPE_PUBLICKEY,
4443 AUTH_TYPE_PUBLICKEY_OFFER_LOUD,
4444 AUTH_TYPE_PUBLICKEY_OFFER_QUIET,
4445 AUTH_TYPE_PASSWORD,
4446 AUTH_TYPE_KEYBOARD_INTERACTIVE,
4447 AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET
4448 } type;
4449 int gotit, need_pw, can_pubkey, can_passwd, can_keyb_inter;
4450 int tried_pubkey_config, tried_agent, tried_keyb_inter;
4451 int kbd_inter_running;
4452 int we_are_in;
4453 int num_prompts, curr_prompt, echo;
4454 char username[100];
4455 int got_username;
4456 char pwprompt[200];
4457 char password[100];
4458 void *publickey_blob;
4459 int publickey_bloblen;
4460 unsigned char request[5], *response, *p;
4461 int responselen;
4462 int keyi, nkeys;
4463 int authed;
4464 char *pkblob, *alg, *commentp;
4465 int pklen, alglen, commentlen;
4466 int siglen, retlen, len;
4467 char *q, *agentreq, *ret;
4468 int try_send;
4469 };
4470 crState(do_ssh2_authconn_state);
4471
4472 crBegin(ssh->do_ssh2_authconn_crstate);
4473
4474 /*
4475 * Request userauth protocol, and await a response to it.
4476 */
4477 ssh2_pkt_init(ssh, SSH2_MSG_SERVICE_REQUEST);
4478 ssh2_pkt_addstring(ssh, "ssh-userauth");
4479 ssh2_pkt_send(ssh);
4480 crWaitUntilV(ispkt);
4481 if (ssh->pktin.type != SSH2_MSG_SERVICE_ACCEPT) {
4482 bombout(("Server refused user authentication protocol"));
4483 crStopV;
4484 }
4485
4486 /*
4487 * We repeat this whole loop, including the username prompt,
4488 * until we manage a successful authentication. If the user
4489 * types the wrong _password_, they can be sent back to the
4490 * beginning to try another username, if this is configured on.
4491 * (If they specify a username in the config, they are never
4492 * asked, even if they do give a wrong password.)
4493 *
4494 * I think this best serves the needs of
4495 *
4496 * - the people who have no configuration, no keys, and just
4497 * want to try repeated (username,password) pairs until they
4498 * type both correctly
4499 *
4500 * - people who have keys and configuration but occasionally
4501 * need to fall back to passwords
4502 *
4503 * - people with a key held in Pageant, who might not have
4504 * logged in to a particular machine before; so they want to
4505 * type a username, and then _either_ their key will be
4506 * accepted, _or_ they will type a password. If they mistype
4507 * the username they will want to be able to get back and
4508 * retype it!
4509 */
4510 s->username[0] = '\0';
4511 s->got_username = FALSE;
4512 do {
4513 /*
4514 * Get a username.
4515 */
4516 if (s->got_username && !ssh->cfg.change_username) {
4517 /*
4518 * We got a username last time round this loop, and
4519 * with change_username turned off we don't try to get
4520 * it again.
4521 */
4522 } else if ((flags & FLAG_INTERACTIVE) && !*ssh->cfg.username) {
4523 if (ssh_get_line && !ssh_getline_pw_only) {
4524 if (!ssh_get_line("login as: ",
4525 s->username, sizeof(s->username), FALSE)) {
4526 /*
4527 * get_line failed to get a username.
4528 * Terminate.
4529 */
4530 logevent("No username provided. Abandoning session.");
4531 ssh_closing((Plug)ssh, NULL, 0, 0);
4532 crStopV;
4533 }
4534 } else {
4535 int ret; /* need not be saved across crReturn */
4536 c_write_str(ssh, "login as: ");
4537 ssh->send_ok = 1;
4538 setup_userpass_input(ssh, s->username, sizeof(s->username), 1);
4539 do {
4540 crWaitUntilV(!ispkt);
4541 ret = process_userpass_input(ssh, in, inlen);
4542 } while (ret == 0);
4543 if (ret < 0)
4544 cleanup_exit(0);
4545 c_write_str(ssh, "\r\n");
4546 }
4547 s->username[strcspn(s->username, "\n\r")] = '\0';
4548 } else {
4549 char *stuff;
4550 strncpy(s->username, ssh->cfg.username, sizeof(s->username));
4551 s->username[sizeof(s->username)-1] = '\0';
4552 if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
4553 stuff = dupprintf("Using username \"%s\".\r\n", s->username);
4554 c_write_str(ssh, stuff);
4555 sfree(stuff);
4556 }
4557 }
4558 s->got_username = TRUE;
4559
4560 /*
4561 * Send an authentication request using method "none": (a)
4562 * just in case it succeeds, and (b) so that we know what
4563 * authentication methods we can usefully try next.
4564 */
4565 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4566
4567 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4568 ssh2_pkt_addstring(ssh, s->username);
4569 ssh2_pkt_addstring(ssh, "ssh-connection");/* service requested */
4570 ssh2_pkt_addstring(ssh, "none"); /* method */
4571 ssh2_pkt_send(ssh);
4572 s->type = AUTH_TYPE_NONE;
4573 s->gotit = FALSE;
4574 s->we_are_in = FALSE;
4575
4576 s->tried_pubkey_config = FALSE;
4577 s->tried_agent = FALSE;
4578 s->tried_keyb_inter = FALSE;
4579 s->kbd_inter_running = FALSE;
4580 /* Load the pub half of ssh->cfg.keyfile so we notice if it's in Pageant */
4581 if (!filename_is_null(ssh->cfg.keyfile)) {
4582 int keytype;
4583 logeventf(ssh, "Reading private key file \"%.150s\"",
4584 filename_to_str(&ssh->cfg.keyfile));
4585 keytype = key_type(&ssh->cfg.keyfile);
4586 if (keytype == SSH_KEYTYPE_SSH2) {
4587 s->publickey_blob =
4588 ssh2_userkey_loadpub(&ssh->cfg.keyfile, NULL,
4589 &s->publickey_bloblen);
4590 } else {
4591 char *msgbuf;
4592 logeventf(ssh, "Unable to use this key file (%s)",
4593 key_type_to_str(keytype));
4594 msgbuf = dupprintf("Unable to use key file \"%.150s\""
4595 " (%s)\r\n",
4596 filename_to_str(&ssh->cfg.keyfile),
4597 key_type_to_str(keytype));
4598 c_write_str(ssh, msgbuf);
4599 sfree(msgbuf);
4600 s->publickey_blob = NULL;
4601 }
4602 } else
4603 s->publickey_blob = NULL;
4604
4605 while (1) {
4606 /*
4607 * Wait for the result of the last authentication request.
4608 */
4609 if (!s->gotit)
4610 crWaitUntilV(ispkt);
4611 while (ssh->pktin.type == SSH2_MSG_USERAUTH_BANNER) {
4612 char *banner;
4613 int size;
4614 /*
4615 * Don't show the banner if we're operating in
4616 * non-verbose non-interactive mode. (It's probably
4617 * a script, which means nobody will read the
4618 * banner _anyway_, and moreover the printing of
4619 * the banner will screw up processing on the
4620 * output of (say) plink.)
4621 */
4622 if (flags & (FLAG_VERBOSE | FLAG_INTERACTIVE)) {
4623 ssh2_pkt_getstring(ssh, &banner, &size);
4624 if (banner)
4625 c_write_untrusted(ssh, banner, size);
4626 }
4627 crWaitUntilV(ispkt);
4628 }
4629 if (ssh->pktin.type == SSH2_MSG_USERAUTH_SUCCESS) {
4630 logevent("Access granted");
4631 s->we_are_in = TRUE;
4632 break;
4633 }
4634
4635 if (s->kbd_inter_running &&
4636 ssh->pktin.type == SSH2_MSG_USERAUTH_INFO_REQUEST) {
4637 /*
4638 * This is either a further set-of-prompts packet
4639 * in keyboard-interactive authentication, or it's
4640 * the same one and we came back here with `gotit'
4641 * set. In the former case, we must reset the
4642 * curr_prompt variable.
4643 */
4644 if (!s->gotit)
4645 s->curr_prompt = 0;
4646 } else if (ssh->pktin.type != SSH2_MSG_USERAUTH_FAILURE) {
4647 bombout(("Strange packet received during authentication: type %d",
4648 ssh->pktin.type));
4649 crStopV;
4650 }
4651
4652 s->gotit = FALSE;
4653
4654 /*
4655 * OK, we're now sitting on a USERAUTH_FAILURE message, so
4656 * we can look at the string in it and know what we can
4657 * helpfully try next.
4658 */
4659 if (ssh->pktin.type == SSH2_MSG_USERAUTH_FAILURE) {
4660 char *methods;
4661 int methlen;
4662 ssh2_pkt_getstring(ssh, &methods, &methlen);
4663 s->kbd_inter_running = FALSE;
4664 if (!ssh2_pkt_getbool(ssh)) {
4665 /*
4666 * We have received an unequivocal Access
4667 * Denied. This can translate to a variety of
4668 * messages:
4669 *
4670 * - if we'd just tried "none" authentication,
4671 * it's not worth printing anything at all
4672 *
4673 * - if we'd just tried a public key _offer_,
4674 * the message should be "Server refused our
4675 * key" (or no message at all if the key
4676 * came from Pageant)
4677 *
4678 * - if we'd just tried anything else, the
4679 * message really should be "Access denied".
4680 *
4681 * Additionally, if we'd just tried password
4682 * authentication, we should break out of this
4683 * whole loop so as to go back to the username
4684 * prompt.
4685 */
4686 if (s->type == AUTH_TYPE_NONE) {
4687 /* do nothing */
4688 } else if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD ||
4689 s->type == AUTH_TYPE_PUBLICKEY_OFFER_QUIET) {
4690 if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD)
4691 c_write_str(ssh, "Server refused our key\r\n");
4692 logevent("Server refused public key");
4693 } else if (s->type==AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET) {
4694 /* server declined keyboard-interactive; ignore */
4695 } else {
4696 c_write_str(ssh, "Access denied\r\n");
4697 logevent("Access denied");
4698 if (s->type == AUTH_TYPE_PASSWORD) {
4699 s->we_are_in = FALSE;
4700 break;
4701 }
4702 }
4703 } else {
4704 c_write_str(ssh, "Further authentication required\r\n");
4705 logevent("Further authentication required");
4706 }
4707
4708 s->can_pubkey =
4709 in_commasep_string("publickey", methods, methlen);
4710 s->can_passwd =
4711 in_commasep_string("password", methods, methlen);
4712 s->can_keyb_inter = ssh->cfg.try_ki_auth &&
4713 in_commasep_string("keyboard-interactive", methods, methlen);
4714 }
4715
4716 s->method = 0;
4717 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4718
4719 /*
4720 * Most password/passphrase prompts will be
4721 * non-echoing, so we set this to 0 by default.
4722 * Exception is that some keyboard-interactive prompts
4723 * can be echoing, in which case we'll set this to 1.
4724 */
4725 s->echo = 0;
4726
4727 if (!s->method && s->can_pubkey &&
4728 agent_exists() && !s->tried_agent) {
4729 /*
4730 * Attempt public-key authentication using Pageant.
4731 */
4732 void *r;
4733 s->authed = FALSE;
4734
4735 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4736 ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
4737
4738 s->tried_agent = TRUE;
4739
4740 logevent("Pageant is running. Requesting keys.");
4741
4742 /* Request the keys held by the agent. */
4743 PUT_32BIT(s->request, 1);
4744 s->request[4] = SSH2_AGENTC_REQUEST_IDENTITIES;
4745 if (!agent_query(s->request, 5, &r, &s->responselen,
4746 ssh_agent_callback, ssh)) {
4747 do {
4748 crReturnV;
4749 if (ispkt) {
4750 bombout(("Unexpected data from server while"
4751 " waiting for agent response"));
4752 crStopV;
4753 }
4754 } while (ispkt || inlen > 0);
4755 r = ssh->agent_response;
4756 s->responselen = ssh->agent_response_len;
4757 }
4758 s->response = (unsigned char *) r;
4759 if (s->response && s->responselen >= 5 &&
4760 s->response[4] == SSH2_AGENT_IDENTITIES_ANSWER) {
4761 s->p = s->response + 5;
4762 s->nkeys = GET_32BIT(s->p);
4763 s->p += 4;
4764 {
4765 char buf[64];
4766 sprintf(buf, "Pageant has %d SSH2 keys", s->nkeys);
4767 logevent(buf);
4768 }
4769 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
4770 void *vret;
4771
4772 {
4773 char buf[64];
4774 sprintf(buf, "Trying Pageant key #%d", s->keyi);
4775 logevent(buf);
4776 }
4777 s->pklen = GET_32BIT(s->p);
4778 s->p += 4;
4779 if (s->publickey_blob &&
4780 s->pklen == s->publickey_bloblen &&
4781 !memcmp(s->p, s->publickey_blob,
4782 s->publickey_bloblen)) {
4783 logevent("This key matches configured key file");
4784 s->tried_pubkey_config = 1;
4785 }
4786 s->pkblob = (char *)s->p;
4787 s->p += s->pklen;
4788 s->alglen = GET_32BIT(s->pkblob);
4789 s->alg = s->pkblob + 4;
4790 s->commentlen = GET_32BIT(s->p);
4791 s->p += 4;
4792 s->commentp = (char *)s->p;
4793 s->p += s->commentlen;
4794 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4795 ssh2_pkt_addstring(ssh, s->username);
4796 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4797 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4798 ssh2_pkt_addbool(ssh, FALSE); /* no signature included */
4799 ssh2_pkt_addstring_start(ssh);
4800 ssh2_pkt_addstring_data(ssh, s->alg, s->alglen);
4801 ssh2_pkt_addstring_start(ssh);
4802 ssh2_pkt_addstring_data(ssh, s->pkblob, s->pklen);
4803 ssh2_pkt_send(ssh);
4804
4805 crWaitUntilV(ispkt);
4806 if (ssh->pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
4807 logevent("Key refused");
4808 continue;
4809 }
4810
4811 if (flags & FLAG_VERBOSE) {
4812 c_write_str(ssh, "Authenticating with "
4813 "public key \"");
4814 c_write(ssh, s->commentp, s->commentlen);
4815 c_write_str(ssh, "\" from agent\r\n");
4816 }
4817
4818 /*
4819 * Server is willing to accept the key.
4820 * Construct a SIGN_REQUEST.
4821 */
4822 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4823 ssh2_pkt_addstring(ssh, s->username);
4824 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4825 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4826 ssh2_pkt_addbool(ssh, TRUE);
4827 ssh2_pkt_addstring_start(ssh);
4828 ssh2_pkt_addstring_data(ssh, s->alg, s->alglen);
4829 ssh2_pkt_addstring_start(ssh);
4830 ssh2_pkt_addstring_data(ssh, s->pkblob, s->pklen);
4831
4832 s->siglen = ssh->pktout.length - 5 + 4 + 20;
4833 if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
4834 s->siglen -= 4;
4835 s->len = 1; /* message type */
4836 s->len += 4 + s->pklen; /* key blob */
4837 s->len += 4 + s->siglen; /* data to sign */
4838 s->len += 4; /* flags */
4839 s->agentreq = snewn(4 + s->len, char);
4840 PUT_32BIT(s->agentreq, s->len);
4841 s->q = s->agentreq + 4;
4842 *s->q++ = SSH2_AGENTC_SIGN_REQUEST;
4843 PUT_32BIT(s->q, s->pklen);
4844 s->q += 4;
4845 memcpy(s->q, s->pkblob, s->pklen);
4846 s->q += s->pklen;
4847 PUT_32BIT(s->q, s->siglen);
4848 s->q += 4;
4849 /* Now the data to be signed... */
4850 if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
4851 PUT_32BIT(s->q, 20);
4852 s->q += 4;
4853 }
4854 memcpy(s->q, ssh->v2_session_id, 20);
4855 s->q += 20;
4856 memcpy(s->q, ssh->pktout.data + 5,
4857 ssh->pktout.length - 5);
4858 s->q += ssh->pktout.length - 5;
4859 /* And finally the (zero) flags word. */
4860 PUT_32BIT(s->q, 0);
4861 if (!agent_query(s->agentreq, s->len + 4,
4862 &vret, &s->retlen,
4863 ssh_agent_callback, ssh)) {
4864 do {
4865 crReturnV;
4866 if (ispkt) {
4867 bombout(("Unexpected data from server"
4868 " while waiting for agent"
4869 " response"));
4870 crStopV;
4871 }
4872 } while (ispkt || inlen > 0);
4873 vret = ssh->agent_response;
4874 s->retlen = ssh->agent_response_len;
4875 }
4876 s->ret = vret;
4877 sfree(s->agentreq);
4878 if (s->ret) {
4879 if (s->ret[4] == SSH2_AGENT_SIGN_RESPONSE) {
4880 logevent("Sending Pageant's response");
4881 ssh2_add_sigblob(ssh, s->pkblob, s->pklen,
4882 s->ret + 9,
4883 GET_32BIT(s->ret + 5));
4884 ssh2_pkt_send(ssh);
4885 s->authed = TRUE;
4886 break;
4887 } else {
4888 logevent
4889 ("Pageant failed to answer challenge");
4890 sfree(s->ret);
4891 }
4892 }
4893 }
4894 if (s->authed)
4895 continue;
4896 }
4897 }
4898
4899 if (!s->method && s->can_pubkey && s->publickey_blob
4900 && !s->tried_pubkey_config) {
4901 unsigned char *pub_blob;
4902 char *algorithm, *comment;
4903 int pub_blob_len;
4904
4905 s->tried_pubkey_config = TRUE;
4906
4907 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4908 ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
4909
4910 /*
4911 * Try the public key supplied in the configuration.
4912 *
4913 * First, offer the public blob to see if the server is
4914 * willing to accept it.
4915 */
4916 pub_blob =
4917 (unsigned char *)ssh2_userkey_loadpub(&ssh->cfg.keyfile,
4918 &algorithm,
4919 &pub_blob_len);
4920 if (pub_blob) {
4921 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4922 ssh2_pkt_addstring(ssh, s->username);
4923 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4924 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4925 ssh2_pkt_addbool(ssh, FALSE); /* no signature included */
4926 ssh2_pkt_addstring(ssh, algorithm);
4927 ssh2_pkt_addstring_start(ssh);
4928 ssh2_pkt_addstring_data(ssh, (char *)pub_blob,
4929 pub_blob_len);
4930 ssh2_pkt_send(ssh);
4931 logevent("Offered public key"); /* FIXME */
4932
4933 crWaitUntilV(ispkt);
4934 if (ssh->pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
4935 s->gotit = TRUE;
4936 s->type = AUTH_TYPE_PUBLICKEY_OFFER_LOUD;
4937 continue; /* key refused; give up on it */
4938 }
4939
4940 logevent("Offer of public key accepted");
4941 /*
4942 * Actually attempt a serious authentication using
4943 * the key.
4944 */
4945 if (ssh2_userkey_encrypted(&ssh->cfg.keyfile, &comment)) {
4946 sprintf(s->pwprompt,
4947 "Passphrase for key \"%.100s\": ",
4948 comment);
4949 s->need_pw = TRUE;
4950 } else {
4951 s->need_pw = FALSE;
4952 }
4953 c_write_str(ssh, "Authenticating with public key \"");
4954 c_write_str(ssh, comment);
4955 c_write_str(ssh, "\"\r\n");
4956 s->method = AUTH_PUBLICKEY_FILE;
4957 }
4958 }
4959
4960 if (!s->method && s->can_keyb_inter && !s->tried_keyb_inter) {
4961 s->method = AUTH_KEYBOARD_INTERACTIVE;
4962 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
4963 s->tried_keyb_inter = TRUE;
4964
4965 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4966 ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;
4967
4968 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4969 ssh2_pkt_addstring(ssh, s->username);
4970 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4971 ssh2_pkt_addstring(ssh, "keyboard-interactive"); /* method */
4972 ssh2_pkt_addstring(ssh, ""); /* lang */
4973 ssh2_pkt_addstring(ssh, "");
4974 ssh2_pkt_send(ssh);
4975
4976 crWaitUntilV(ispkt);
4977 if (ssh->pktin.type != SSH2_MSG_USERAUTH_INFO_REQUEST) {
4978 if (ssh->pktin.type == SSH2_MSG_USERAUTH_FAILURE)
4979 s->gotit = TRUE;
4980 logevent("Keyboard-interactive authentication refused");
4981 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET;
4982 continue;
4983 }
4984
4985 s->kbd_inter_running = TRUE;
4986 s->curr_prompt = 0;
4987 }
4988
4989 if (s->kbd_inter_running) {
4990 s->method = AUTH_KEYBOARD_INTERACTIVE;
4991 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
4992 s->tried_keyb_inter = TRUE;
4993
4994 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4995 ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;
4996
4997 if (s->curr_prompt == 0) {
4998 /*
4999 * We've got a fresh USERAUTH_INFO_REQUEST.
5000 * Display header data, and start going through
5001 * the prompts.
5002 */
5003 char *name, *inst, *lang;
5004 int name_len, inst_len, lang_len;
5005
5006 ssh2_pkt_getstring(ssh, &name, &name_len);
5007 ssh2_pkt_getstring(ssh, &inst, &inst_len);
5008 ssh2_pkt_getstring(ssh, &lang, &lang_len);
5009 if (name_len > 0) {
5010 c_write_untrusted(ssh, name, name_len);
5011 c_write_str(ssh, "\r\n");
5012 }
5013 if (inst_len > 0) {
5014 c_write_untrusted(ssh, inst, inst_len);
5015 c_write_str(ssh, "\r\n");
5016 }
5017 s->num_prompts = ssh2_pkt_getuint32(ssh);
5018 }
5019
5020 /*
5021 * If there are prompts remaining in the packet,
5022 * display one and get a response.
5023 */
5024 if (s->curr_prompt < s->num_prompts) {
5025 char *prompt;
5026 int prompt_len;
5027
5028 ssh2_pkt_getstring(ssh, &prompt, &prompt_len);
5029 if (prompt_len > 0) {
5030 strncpy(s->pwprompt, prompt, sizeof(s->pwprompt));
5031 s->pwprompt[prompt_len < sizeof(s->pwprompt) ?
5032 prompt_len : sizeof(s->pwprompt)-1] = '\0';
5033 } else {
5034 strcpy(s->pwprompt,
5035 "<server failed to send prompt>: ");
5036 }
5037 s->echo = ssh2_pkt_getbool(ssh);
5038 s->need_pw = TRUE;
5039 } else
5040 s->need_pw = FALSE;
5041 }
5042
5043 if (!s->method && s->can_passwd) {
5044 s->method = AUTH_PASSWORD;
5045 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
5046 ssh->pkt_ctx |= SSH2_PKTCTX_PASSWORD;
5047 sprintf(s->pwprompt, "%.90s@%.90s's password: ", s->username,
5048 ssh->savedhost);
5049 s->need_pw = TRUE;
5050 }
5051
5052 if (s->need_pw) {
5053 if (ssh_get_line) {
5054 if (!ssh_get_line(s->pwprompt, s->password,
5055 sizeof(s->password), TRUE)) {
5056 /*
5057 * get_line failed to get a password (for
5058 * example because one was supplied on the
5059 * command line which has already failed to
5060 * work). Terminate.
5061 */
5062 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5063 ssh2_pkt_adduint32(ssh,SSH2_DISCONNECT_BY_APPLICATION);
5064 ssh2_pkt_addstring(ssh, "No more passwords available"
5065 " to try");
5066 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5067 ssh2_pkt_send(ssh);
5068 logevent("Unable to authenticate");
5069 connection_fatal(ssh->frontend,
5070 "Unable to authenticate");
5071 ssh_closing((Plug)ssh, NULL, 0, 0);
5072 crStopV;
5073 }
5074 } else {
5075 int ret; /* need not be saved across crReturn */
5076 c_write_untrusted(ssh, s->pwprompt, strlen(s->pwprompt));
5077 ssh->send_ok = 1;
5078
5079 setup_userpass_input(ssh, s->password,
5080 sizeof(s->password), s->echo);
5081 do {
5082 crWaitUntilV(!ispkt);
5083 ret = process_userpass_input(ssh, in, inlen);
5084 } while (ret == 0);
5085 if (ret < 0)
5086 cleanup_exit(0);
5087 c_write_str(ssh, "\r\n");
5088 }
5089 }
5090
5091 if (s->method == AUTH_PUBLICKEY_FILE) {
5092 /*
5093 * We have our passphrase. Now try the actual authentication.
5094 */
5095 struct ssh2_userkey *key;
5096
5097 key = ssh2_load_userkey(&ssh->cfg.keyfile, s->password);
5098 if (key == SSH2_WRONG_PASSPHRASE || key == NULL) {
5099 if (key == SSH2_WRONG_PASSPHRASE) {
5100 c_write_str(ssh, "Wrong passphrase\r\n");
5101 s->tried_pubkey_config = FALSE;
5102 } else {
5103 c_write_str(ssh, "Unable to load private key\r\n");
5104 s->tried_pubkey_config = TRUE;
5105 }
5106 /* Send a spurious AUTH_NONE to return to the top. */
5107 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
5108 ssh2_pkt_addstring(ssh, s->username);
5109 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
5110 ssh2_pkt_addstring(ssh, "none"); /* method */
5111 ssh2_pkt_send(ssh);
5112 s->type = AUTH_TYPE_NONE;
5113 } else {
5114 unsigned char *pkblob, *sigblob, *sigdata;
5115 int pkblob_len, sigblob_len, sigdata_len;
5116 int p;
5117
5118 /*
5119 * We have loaded the private key and the server
5120 * has announced that it's willing to accept it.
5121 * Hallelujah. Generate a signature and send it.
5122 */
5123 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
5124 ssh2_pkt_addstring(ssh, s->username);
5125 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
5126 ssh2_pkt_addstring(ssh, "publickey"); /* method */
5127 ssh2_pkt_addbool(ssh, TRUE);
5128 ssh2_pkt_addstring(ssh, key->alg->name);
5129 pkblob = key->alg->public_blob(key->data, &pkblob_len);
5130 ssh2_pkt_addstring_start(ssh);
5131 ssh2_pkt_addstring_data(ssh, (char *)pkblob, pkblob_len);
5132
5133 /*
5134 * The data to be signed is:
5135 *
5136 * string session-id
5137 *
5138 * followed by everything so far placed in the
5139 * outgoing packet.
5140 */
5141 sigdata_len = ssh->pktout.length - 5 + 4 + 20;
5142 if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
5143 sigdata_len -= 4;
5144 sigdata = snewn(sigdata_len, unsigned char);
5145 p = 0;
5146 if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
5147 PUT_32BIT(sigdata+p, 20);
5148 p += 4;
5149 }
5150 memcpy(sigdata+p, ssh->v2_session_id, 20); p += 20;
5151 memcpy(sigdata+p, ssh->pktout.data + 5,
5152 ssh->pktout.length - 5);
5153 p += ssh->pktout.length - 5;
5154 assert(p == sigdata_len);
5155 sigblob = key->alg->sign(key->data, (char *)sigdata,
5156 sigdata_len, &sigblob_len);
5157 ssh2_add_sigblob(ssh, pkblob, pkblob_len,
5158 sigblob, sigblob_len);
5159 sfree(pkblob);
5160 sfree(sigblob);
5161 sfree(sigdata);
5162
5163 ssh2_pkt_send(ssh);
5164 s->type = AUTH_TYPE_PUBLICKEY;
5165 }
5166 } else if (s->method == AUTH_PASSWORD) {
5167 /*
5168 * We send the password packet lumped tightly together with
5169 * an SSH_MSG_IGNORE packet. The IGNORE packet contains a
5170 * string long enough to make the total length of the two
5171 * packets constant. This should ensure that a passive
5172 * listener doing traffic analyis can't work out the length
5173 * of the password.
5174 *
5175 * For this to work, we need an assumption about the
5176 * maximum length of the password packet. I think 256 is
5177 * pretty conservative. Anyone using a password longer than
5178 * that probably doesn't have much to worry about from
5179 * people who find out how long their password is!
5180 */
5181 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
5182 ssh2_pkt_addstring(ssh, s->username);
5183 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
5184 ssh2_pkt_addstring(ssh, "password");
5185 ssh2_pkt_addbool(ssh, FALSE);
5186 ssh2_pkt_addstring(ssh, s->password);
5187 memset(s->password, 0, sizeof(s->password));
5188 ssh2_pkt_defer(ssh);
5189 /*
5190 * We'll include a string that's an exact multiple of the
5191 * cipher block size. If the cipher is NULL for some
5192 * reason, we don't do this trick at all because we gain
5193 * nothing by it.
5194 */
5195 if (ssh->cscipher) {
5196 int stringlen, i;
5197
5198 stringlen = (256 - ssh->deferred_len);
5199 stringlen += ssh->cscipher->blksize - 1;
5200 stringlen -= (stringlen % ssh->cscipher->blksize);
5201 if (ssh->cscomp) {
5202 /*
5203 * Temporarily disable actual compression,
5204 * so we can guarantee to get this string
5205 * exactly the length we want it. The
5206 * compression-disabling routine should
5207 * return an integer indicating how many
5208 * bytes we should adjust our string length
5209 * by.
5210 */
5211 stringlen -=
5212 ssh->cscomp->disable_compression(ssh->cs_comp_ctx);
5213 }
5214 ssh2_pkt_init(ssh, SSH2_MSG_IGNORE);
5215 ssh2_pkt_addstring_start(ssh);
5216 for (i = 0; i < stringlen; i++) {
5217 char c = (char) random_byte();
5218 ssh2_pkt_addstring_data(ssh, &c, 1);
5219 }
5220 ssh2_pkt_defer(ssh);
5221 }
5222 ssh_pkt_defersend(ssh);
5223 logevent("Sent password");
5224 s->type = AUTH_TYPE_PASSWORD;
5225 } else if (s->method == AUTH_KEYBOARD_INTERACTIVE) {
5226 if (s->curr_prompt == 0) {
5227 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_INFO_RESPONSE);
5228 ssh2_pkt_adduint32(ssh, s->num_prompts);
5229 }
5230 if (s->need_pw) { /* only add pw if we just got one! */
5231 ssh2_pkt_addstring(ssh, s->password);
5232 memset(s->password, 0, sizeof(s->password));
5233 s->curr_prompt++;
5234 }
5235 if (s->curr_prompt >= s->num_prompts) {
5236 ssh2_pkt_send(ssh);
5237 } else {
5238 /*
5239 * If there are prompts remaining, we set
5240 * `gotit' so that we won't attempt to get
5241 * another packet. Then we go back round the
5242 * loop and will end up retrieving another
5243 * prompt out of the existing packet. Funky or
5244 * what?
5245 */
5246 s->gotit = TRUE;
5247 }
5248 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
5249 } else {
5250 c_write_str(ssh, "No supported authentication methods"
5251 " left to try!\r\n");
5252 logevent("No supported authentications offered."
5253 " Disconnecting");
5254 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5255 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5256 ssh2_pkt_addstring(ssh, "No supported authentication"
5257 " methods available");
5258 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5259 ssh2_pkt_send(ssh);
5260 ssh_closing((Plug)ssh, NULL, 0, 0);
5261 crStopV;
5262 }
5263 }
5264 } while (!s->we_are_in);
5265
5266 /*
5267 * Now we're authenticated for the connection protocol. The
5268 * connection protocol will automatically have started at this
5269 * point; there's no need to send SERVICE_REQUEST.
5270 */
5271
5272 /*
5273 * So now create a channel with a session in it.
5274 */
5275 ssh->channels = newtree234(ssh_channelcmp);
5276 ssh->mainchan = snew(struct ssh_channel);
5277 ssh->mainchan->ssh = ssh;
5278 ssh->mainchan->localid = alloc_channel_id(ssh);
5279 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN);
5280 ssh2_pkt_addstring(ssh, "session");
5281 ssh2_pkt_adduint32(ssh, ssh->mainchan->localid);
5282 ssh->mainchan->v.v2.locwindow = OUR_V2_WINSIZE;
5283 ssh2_pkt_adduint32(ssh, ssh->mainchan->v.v2.locwindow);/* our window size */
5284 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
5285 ssh2_pkt_send(ssh);
5286 crWaitUntilV(ispkt);
5287 if (ssh->pktin.type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
5288 bombout(("Server refused to open a session"));
5289 crStopV;
5290 /* FIXME: error data comes back in FAILURE packet */
5291 }
5292 if (ssh2_pkt_getuint32(ssh) != ssh->mainchan->localid) {
5293 bombout(("Server's channel confirmation cited wrong channel"));
5294 crStopV;
5295 }
5296 ssh->mainchan->remoteid = ssh2_pkt_getuint32(ssh);
5297 ssh->mainchan->type = CHAN_MAINSESSION;
5298 ssh->mainchan->closes = 0;
5299 ssh->mainchan->v.v2.remwindow = ssh2_pkt_getuint32(ssh);
5300 ssh->mainchan->v.v2.remmaxpkt = ssh2_pkt_getuint32(ssh);
5301 bufchain_init(&ssh->mainchan->v.v2.outbuffer);
5302 add234(ssh->channels, ssh->mainchan);
5303 logevent("Opened channel for session");
5304
5305 /*
5306 * Potentially enable X11 forwarding.
5307 */
5308 if (ssh->cfg.x11_forward) {
5309 char proto[20], data[64];
5310 logevent("Requesting X11 forwarding");
5311 ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
5312 data, sizeof(data), ssh->cfg.x11_auth);
5313 x11_get_real_auth(ssh->x11auth, ssh->cfg.x11_display);
5314 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5315 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
5316 ssh2_pkt_addstring(ssh, "x11-req");
5317 ssh2_pkt_addbool(ssh, 1); /* want reply */
5318 ssh2_pkt_addbool(ssh, 0); /* many connections */
5319 ssh2_pkt_addstring(ssh, proto);
5320 ssh2_pkt_addstring(ssh, data);
5321 ssh2_pkt_adduint32(ssh, x11_get_screen_number(ssh->cfg.x11_display));
5322 ssh2_pkt_send(ssh);
5323
5324 do {
5325 crWaitUntilV(ispkt);
5326 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5327 unsigned i = ssh2_pkt_getuint32(ssh);
5328 struct ssh_channel *c;
5329 c = find234(ssh->channels, &i, ssh_channelfind);
5330 if (!c)
5331 continue; /* nonexistent channel */
5332 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5333 }
5334 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5335
5336 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5337 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5338 bombout(("Unexpected response to X11 forwarding request:"
5339 " packet type %d", ssh->pktin.type));
5340 crStopV;
5341 }
5342 logevent("X11 forwarding refused");
5343 } else {
5344 logevent("X11 forwarding enabled");
5345 ssh->X11_fwd_enabled = TRUE;
5346 }
5347 }
5348
5349 /*
5350 * Enable port forwardings.
5351 */
5352 {
5353 char type;
5354 int n;
5355 int sport,dport,sserv,dserv;
5356 char sports[256], dports[256], saddr[256], host[256];
5357
5358 ssh->rportfwds = newtree234(ssh_rportcmp_ssh2);
5359 /* Add port forwardings. */
5360 ssh->portfwd_strptr = ssh->cfg.portfwd;
5361 while (*ssh->portfwd_strptr) {
5362 type = *ssh->portfwd_strptr++;
5363 saddr[0] = '\0';
5364 n = 0;
5365 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != '\t') {
5366 if (*ssh->portfwd_strptr == ':') {
5367 /*
5368 * We've seen a colon in the middle of the
5369 * source port number. This means that
5370 * everything we've seen until now is the
5371 * source _address_, so we'll move it into
5372 * saddr and start sports from the beginning
5373 * again.
5374 */
5375 ssh->portfwd_strptr++;
5376 sports[n] = '\0';
5377 strcpy(saddr, sports);
5378 n = 0;
5379 }
5380 if (n < 255) sports[n++] = *ssh->portfwd_strptr++;
5381 }
5382 sports[n] = 0;
5383 if (type != 'D') {
5384 if (*ssh->portfwd_strptr == '\t')
5385 ssh->portfwd_strptr++;
5386 n = 0;
5387 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':') {
5388 if (n < 255) host[n++] = *ssh->portfwd_strptr++;
5389 }
5390 host[n] = 0;
5391 if (*ssh->portfwd_strptr == ':')
5392 ssh->portfwd_strptr++;
5393 n = 0;
5394 while (*ssh->portfwd_strptr) {
5395 if (n < 255) dports[n++] = *ssh->portfwd_strptr++;
5396 }
5397 dports[n] = 0;
5398 ssh->portfwd_strptr++;
5399 dport = atoi(dports);
5400 dserv = 0;
5401 if (dport == 0) {
5402 dserv = 1;
5403 dport = net_service_lookup(dports);
5404 if (!dport) {
5405 logeventf(ssh, "Service lookup failed for destination"
5406 " port \"%s\"", dports);
5407 }
5408 }
5409 } else {
5410 while (*ssh->portfwd_strptr) ssh->portfwd_strptr++;
5411 dport = dserv = -1;
5412 }
5413 sport = atoi(sports);
5414 sserv = 0;
5415 if (sport == 0) {
5416 sserv = 1;
5417 sport = net_service_lookup(sports);
5418 if (!sport) {
5419 logeventf(ssh, "Service lookup failed for source"
5420 " port \"%s\"", sports);
5421 }
5422 }
5423 if (sport && dport) {
5424 if (type == 'L') {
5425 pfd_addforward(host, dport, *saddr ? saddr : NULL,
5426 sport, ssh, &ssh->cfg);
5427 logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
5428 " forwarding to %s:%.*s%.*s%d%.*s",
5429 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
5430 (int)(*saddr?1:0), ":",
5431 (int)(sserv ? strlen(sports) : 0), sports,
5432 sserv, "(", sport, sserv, ")",
5433 host,
5434 (int)(dserv ? strlen(dports) : 0), dports,
5435 dserv, "(", dport, dserv, ")");
5436 } else if (type == 'D') {
5437 pfd_addforward(NULL, -1, *saddr ? saddr : NULL,
5438 sport, ssh, &ssh->cfg);
5439 logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
5440 " doing SOCKS dynamic forwarding",
5441 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
5442 (int)(*saddr?1:0), ":",
5443 (int)(sserv ? strlen(sports) : 0), sports,
5444 sserv, "(", sport, sserv, ")");
5445 } else {
5446 struct ssh_rportfwd *pf;
5447 pf = snew(struct ssh_rportfwd);
5448 strcpy(pf->dhost, host);
5449 pf->dport = dport;
5450 pf->sport = sport;
5451 if (add234(ssh->rportfwds, pf) != pf) {
5452 logeventf(ssh, "Duplicate remote port forwarding"
5453 " to %s:%d", host, dport);
5454 sfree(pf);
5455 } else {
5456 logeventf(ssh, "Requesting remote port "
5457 "%.*s%.*s%.*s%.*s%d%.*s"
5458 " forward to %s:%.*s%.*s%d%.*s",
5459 (int)(*saddr?strlen(saddr):0),
5460 *saddr?saddr:NULL,
5461 (int)(*saddr?1:0), ":",
5462 (int)(sserv ? strlen(sports) : 0), sports,
5463 sserv, "(", sport, sserv, ")",
5464 host,
5465 (int)(dserv ? strlen(dports) : 0), dports,
5466 dserv, "(", dport, dserv, ")");
5467 ssh2_pkt_init(ssh, SSH2_MSG_GLOBAL_REQUEST);
5468 ssh2_pkt_addstring(ssh, "tcpip-forward");
5469 ssh2_pkt_addbool(ssh, 1);/* want reply */
5470 if (*saddr)
5471 ssh2_pkt_addstring(ssh, saddr);
5472 if (ssh->cfg.rport_acceptall)
5473 ssh2_pkt_addstring(ssh, "0.0.0.0");
5474 else
5475 ssh2_pkt_addstring(ssh, "127.0.0.1");
5476 ssh2_pkt_adduint32(ssh, sport);
5477 ssh2_pkt_send(ssh);
5478
5479 do {
5480 crWaitUntilV(ispkt);
5481 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5482 unsigned i = ssh2_pkt_getuint32(ssh);
5483 struct ssh_channel *c;
5484 c = find234(ssh->channels, &i, ssh_channelfind);
5485 if (!c)
5486 continue;/* nonexistent channel */
5487 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5488 }
5489 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5490
5491 if (ssh->pktin.type != SSH2_MSG_REQUEST_SUCCESS) {
5492 if (ssh->pktin.type != SSH2_MSG_REQUEST_FAILURE) {
5493 bombout(("Unexpected response to port "
5494 "forwarding request: packet type %d",
5495 ssh->pktin.type));
5496 crStopV;
5497 }
5498 logevent("Server refused this port forwarding");
5499 } else {
5500 logevent("Remote port forwarding enabled");
5501 }
5502 }
5503 }
5504 }
5505 }
5506 }
5507
5508 /*
5509 * Potentially enable agent forwarding.
5510 */
5511 if (ssh->cfg.agentfwd && agent_exists()) {
5512 logevent("Requesting OpenSSH-style agent forwarding");
5513 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5514 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
5515 ssh2_pkt_addstring(ssh, "auth-agent-req@openssh.com");
5516 ssh2_pkt_addbool(ssh, 1); /* want reply */
5517 ssh2_pkt_send(ssh);
5518
5519 do {
5520 crWaitUntilV(ispkt);
5521 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5522 unsigned i = ssh2_pkt_getuint32(ssh);
5523 struct ssh_channel *c;
5524 c = find234(ssh->channels, &i, ssh_channelfind);
5525 if (!c)
5526 continue; /* nonexistent channel */
5527 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5528 }
5529 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5530
5531 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5532 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5533 bombout(("Unexpected response to agent forwarding request:"
5534 " packet type %d", ssh->pktin.type));
5535 crStopV;
5536 }
5537 logevent("Agent forwarding refused");
5538 } else {
5539 logevent("Agent forwarding enabled");
5540 ssh->agentfwd_enabled = TRUE;
5541 }
5542 }
5543
5544 /*
5545 * Now allocate a pty for the session.
5546 */
5547 if (!ssh->cfg.nopty) {
5548 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5549 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid); /* recipient channel */
5550 ssh2_pkt_addstring(ssh, "pty-req");
5551 ssh2_pkt_addbool(ssh, 1); /* want reply */
5552 ssh2_pkt_addstring(ssh, ssh->cfg.termtype);
5553 ssh2_pkt_adduint32(ssh, ssh->term_width);
5554 ssh2_pkt_adduint32(ssh, ssh->term_height);
5555 ssh2_pkt_adduint32(ssh, 0); /* pixel width */
5556 ssh2_pkt_adduint32(ssh, 0); /* pixel height */
5557 ssh2_pkt_addstring_start(ssh);
5558 ssh2_pkt_addstring_data(ssh, "\0", 1); /* TTY_OP_END, no special options */
5559 ssh2_pkt_send(ssh);
5560 ssh->state = SSH_STATE_INTERMED;
5561
5562 do {
5563 crWaitUntilV(ispkt);
5564 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5565 unsigned i = ssh2_pkt_getuint32(ssh);
5566 struct ssh_channel *c;
5567 c = find234(ssh->channels, &i, ssh_channelfind);
5568 if (!c)
5569 continue; /* nonexistent channel */
5570 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5571 }
5572 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5573
5574 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5575 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5576 bombout(("Unexpected response to pty request:"
5577 " packet type %d", ssh->pktin.type));
5578 crStopV;
5579 }
5580 c_write_str(ssh, "Server refused to allocate pty\r\n");
5581 ssh->editing = ssh->echoing = 1;
5582 } else {
5583 logevent("Allocated pty");
5584 }
5585 } else {
5586 ssh->editing = ssh->echoing = 1;
5587 }
5588
5589 /*
5590 * Start a shell or a remote command. We may have to attempt
5591 * this twice if the config data has provided a second choice
5592 * of command.
5593 */
5594 while (1) {
5595 int subsys;
5596 char *cmd;
5597
5598 if (ssh->fallback_cmd) {
5599 subsys = ssh->cfg.ssh_subsys2;
5600 cmd = ssh->cfg.remote_cmd_ptr2;
5601 } else {
5602 subsys = ssh->cfg.ssh_subsys;
5603 cmd = ssh->cfg.remote_cmd_ptr;
5604 }
5605
5606 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5607 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid); /* recipient channel */
5608 if (subsys) {
5609 ssh2_pkt_addstring(ssh, "subsystem");
5610 ssh2_pkt_addbool(ssh, 1); /* want reply */
5611 ssh2_pkt_addstring(ssh, cmd);
5612 } else if (*cmd) {
5613 ssh2_pkt_addstring(ssh, "exec");
5614 ssh2_pkt_addbool(ssh, 1); /* want reply */
5615 ssh2_pkt_addstring(ssh, cmd);
5616 } else {
5617 ssh2_pkt_addstring(ssh, "shell");
5618 ssh2_pkt_addbool(ssh, 1); /* want reply */
5619 }
5620 ssh2_pkt_send(ssh);
5621 do {
5622 crWaitUntilV(ispkt);
5623 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5624 unsigned i = ssh2_pkt_getuint32(ssh);
5625 struct ssh_channel *c;
5626 c = find234(ssh->channels, &i, ssh_channelfind);
5627 if (!c)
5628 continue; /* nonexistent channel */
5629 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5630 }
5631 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5632 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5633 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5634 bombout(("Unexpected response to shell/command request:"
5635 " packet type %d", ssh->pktin.type));
5636 crStopV;
5637 }
5638 /*
5639 * We failed to start the command. If this is the
5640 * fallback command, we really are finished; if it's
5641 * not, and if the fallback command exists, try falling
5642 * back to it before complaining.
5643 */
5644 if (!ssh->fallback_cmd && ssh->cfg.remote_cmd_ptr2 != NULL) {
5645 logevent("Primary command failed; attempting fallback");
5646 ssh->fallback_cmd = TRUE;
5647 continue;
5648 }
5649 bombout(("Server refused to start a shell/command"));
5650 crStopV;
5651 } else {
5652 logevent("Started a shell/command");
5653 }
5654 break;
5655 }
5656
5657 ssh->state = SSH_STATE_SESSION;
5658 if (ssh->size_needed)
5659 ssh_size(ssh, ssh->term_width, ssh->term_height);
5660 if (ssh->eof_needed)
5661 ssh_special(ssh, TS_EOF);
5662
5663 /*
5664 * Transfer data!
5665 */
5666 if (ssh->ldisc)
5667 ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */
5668 ssh->send_ok = 1;
5669 while (1) {
5670 crReturnV;
5671 s->try_send = FALSE;
5672 if (ispkt) {
5673 if (ssh->pktin.type == SSH2_MSG_CHANNEL_DATA ||
5674 ssh->pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA) {
5675 char *data;
5676 int length;
5677 unsigned i = ssh2_pkt_getuint32(ssh);
5678 struct ssh_channel *c;
5679 c = find234(ssh->channels, &i, ssh_channelfind);
5680 if (!c)
5681 continue; /* nonexistent channel */
5682 if (ssh->pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
5683 ssh2_pkt_getuint32(ssh) != SSH2_EXTENDED_DATA_STDERR)
5684 continue; /* extended but not stderr */
5685 ssh2_pkt_getstring(ssh, &data, &length);
5686 if (data) {
5687 int bufsize = 0;
5688 c->v.v2.locwindow -= length;
5689 switch (c->type) {
5690 case CHAN_MAINSESSION:
5691 bufsize =
5692 from_backend(ssh->frontend, ssh->pktin.type ==
5693 SSH2_MSG_CHANNEL_EXTENDED_DATA,
5694 data, length);
5695 break;
5696 case CHAN_X11:
5697 bufsize = x11_send(c->u.x11.s, data, length);
5698 break;
5699 case CHAN_SOCKDATA:
5700 bufsize = pfd_send(c->u.pfd.s, data, length);
5701 break;
5702 case CHAN_AGENT:
5703 while (length > 0) {
5704 if (c->u.a.lensofar < 4) {
5705 int l = min(4 - c->u.a.lensofar, length);
5706 memcpy(c->u.a.msglen + c->u.a.lensofar,
5707 data, l);
5708 data += l;
5709 length -= l;
5710 c->u.a.lensofar += l;
5711 }
5712 if (c->u.a.lensofar == 4) {
5713 c->u.a.totallen =
5714 4 + GET_32BIT(c->u.a.msglen);
5715 c->u.a.message = snewn(c->u.a.totallen,
5716 unsigned char);
5717 memcpy(c->u.a.message, c->u.a.msglen, 4);
5718 }
5719 if (c->u.a.lensofar >= 4 && length > 0) {
5720 int l =
5721 min(c->u.a.totallen - c->u.a.lensofar,
5722 length);
5723 memcpy(c->u.a.message + c->u.a.lensofar,
5724 data, l);
5725 data += l;
5726 length -= l;
5727 c->u.a.lensofar += l;
5728 }
5729 if (c->u.a.lensofar == c->u.a.totallen) {
5730 void *reply;
5731 int replylen;
5732 if (agent_query(c->u.a.message,
5733 c->u.a.totallen,
5734 &reply, &replylen,
5735 ssh_agentf_callback, c))
5736 ssh_agentf_callback(c, reply, replylen);
5737 sfree(c->u.a.message);
5738 c->u.a.lensofar = 0;
5739 }
5740 }
5741 bufsize = 0;
5742 break;
5743 }
5744 /*
5745 * If we are not buffering too much data,
5746 * enlarge the window again at the remote side.
5747 */
5748 if (bufsize < OUR_V2_WINSIZE)
5749 ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
5750 }
5751 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_EOF) {
5752 unsigned i = ssh2_pkt_getuint32(ssh);
5753 struct ssh_channel *c;
5754
5755 c = find234(ssh->channels, &i, ssh_channelfind);
5756 if (!c)
5757 continue; /* nonexistent channel */
5758
5759 if (c->type == CHAN_X11) {
5760 /*
5761 * Remote EOF on an X11 channel means we should
5762 * wrap up and close the channel ourselves.
5763 */
5764 x11_close(c->u.x11.s);
5765 sshfwd_close(c);
5766 } else if (c->type == CHAN_AGENT) {
5767 sshfwd_close(c);
5768 } else if (c->type == CHAN_SOCKDATA) {
5769 pfd_close(c->u.pfd.s);
5770 sshfwd_close(c);
5771 }
5772 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_CLOSE) {
5773 unsigned i = ssh2_pkt_getuint32(ssh);
5774 struct ssh_channel *c;
5775
5776 c = find234(ssh->channels, &i, ssh_channelfind);
5777 if (!c || ((int)c->remoteid) == -1) {
5778 bombout(("Received CHANNEL_CLOSE for %s channel %d\n",
5779 c ? "half-open" : "nonexistent", i));
5780 crStopV;
5781 }
5782 /* Do pre-close processing on the channel. */
5783 switch (c->type) {
5784 case CHAN_MAINSESSION:
5785 break; /* nothing to see here, move along */
5786 case CHAN_X11:
5787 if (c->u.x11.s != NULL)
5788 x11_close(c->u.x11.s);
5789 sshfwd_close(c);
5790 break;
5791 case CHAN_AGENT:
5792 sshfwd_close(c);
5793 break;
5794 case CHAN_SOCKDATA:
5795 if (c->u.pfd.s != NULL)
5796 pfd_close(c->u.pfd.s);
5797 sshfwd_close(c);
5798 break;
5799 }
5800 if (c->closes == 0) {
5801 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
5802 ssh2_pkt_adduint32(ssh, c->remoteid);
5803 ssh2_pkt_send(ssh);
5804 }
5805 del234(ssh->channels, c);
5806 bufchain_clear(&c->v.v2.outbuffer);
5807 sfree(c);
5808
5809 /*
5810 * See if that was the last channel left open.
5811 */
5812 if (count234(ssh->channels) == 0) {
5813 logevent("All channels closed. Disconnecting");
5814 #if 0
5815 /*
5816 * We used to send SSH_MSG_DISCONNECT here,
5817 * because I'd believed that _every_ conforming
5818 * SSH2 connection had to end with a disconnect
5819 * being sent by at least one side; apparently
5820 * I was wrong and it's perfectly OK to
5821 * unceremoniously slam the connection shut
5822 * when you're done, and indeed OpenSSH feels
5823 * this is more polite than sending a
5824 * DISCONNECT. So now we don't.
5825 */
5826 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5827 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5828 ssh2_pkt_addstring(ssh, "All open channels closed");
5829 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5830 ssh2_pkt_send(ssh);
5831 #endif
5832 ssh_closing((Plug)ssh, NULL, 0, 0);
5833 crStopV;
5834 }
5835 continue; /* remote sends close; ignore (FIXME) */
5836 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5837 unsigned i = ssh2_pkt_getuint32(ssh);
5838 struct ssh_channel *c;
5839 c = find234(ssh->channels, &i, ssh_channelfind);
5840 if (!c || c->closes)
5841 continue; /* nonexistent or closing channel */
5842 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5843 s->try_send = TRUE;
5844 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
5845 unsigned i = ssh2_pkt_getuint32(ssh);
5846 struct ssh_channel *c;
5847 c = find234(ssh->channels, &i, ssh_channelfind);
5848 if (!c)
5849 continue; /* nonexistent channel */
5850 if (c->type != CHAN_SOCKDATA_DORMANT)
5851 continue; /* dunno why they're confirming this */
5852 c->remoteid = ssh2_pkt_getuint32(ssh);
5853 c->type = CHAN_SOCKDATA;
5854 c->v.v2.remwindow = ssh2_pkt_getuint32(ssh);
5855 c->v.v2.remmaxpkt = ssh2_pkt_getuint32(ssh);
5856 if (c->u.pfd.s)
5857 pfd_confirm(c->u.pfd.s);
5858 if (c->closes) {
5859 /*
5860 * We have a pending close on this channel,
5861 * which we decided on before the server acked
5862 * the channel open. So now we know the
5863 * remoteid, we can close it again.
5864 */
5865 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
5866 ssh2_pkt_adduint32(ssh, c->remoteid);
5867 ssh2_pkt_send(ssh);
5868 }
5869 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN_FAILURE) {
5870 unsigned i = ssh2_pkt_getuint32(ssh);
5871 struct ssh_channel *c;
5872 c = find234(ssh->channels, &i, ssh_channelfind);
5873 if (!c)
5874 continue; /* nonexistent channel */
5875 if (c->type != CHAN_SOCKDATA_DORMANT)
5876 continue; /* dunno why they're failing this */
5877
5878 logevent("Forwarded connection refused by server");
5879
5880 pfd_close(c->u.pfd.s);
5881
5882 del234(ssh->channels, c);
5883 sfree(c);
5884 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_REQUEST) {
5885 unsigned localid;
5886 char *type;
5887 int typelen, want_reply;
5888 struct ssh_channel *c;
5889
5890 localid = ssh2_pkt_getuint32(ssh);
5891 ssh2_pkt_getstring(ssh, &type, &typelen);
5892 want_reply = ssh2_pkt_getbool(ssh);
5893
5894 /*
5895 * First, check that the channel exists. Otherwise,
5896 * we can instantly disconnect with a rude message.
5897 */
5898 c = find234(ssh->channels, &localid, ssh_channelfind);
5899 if (!c) {
5900 char buf[80];
5901 sprintf(buf, "Received channel request for nonexistent"
5902 " channel %d", localid);
5903 logevent(buf);
5904 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5905 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5906 ssh2_pkt_addstring(ssh, buf);
5907 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5908 ssh2_pkt_send(ssh);
5909 connection_fatal(ssh->frontend, "%s", buf);
5910 ssh_closing((Plug)ssh, NULL, 0, 0);
5911 crStopV;
5912 }
5913
5914 /*
5915 * Having got the channel number, we now look at
5916 * the request type string to see if it's something
5917 * we recognise.
5918 */
5919 if (typelen == 11 && !memcmp(type, "exit-status", 11) &&
5920 c == ssh->mainchan) {
5921 /* We recognise "exit-status" on the primary channel. */
5922 char buf[100];
5923 ssh->exitcode = ssh2_pkt_getuint32(ssh);
5924 sprintf(buf, "Server sent command exit status %d",
5925 ssh->exitcode);
5926 logevent(buf);
5927 if (want_reply) {
5928 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_SUCCESS);
5929 ssh2_pkt_adduint32(ssh, c->remoteid);
5930 ssh2_pkt_send(ssh);
5931 }
5932 } else {
5933 /*
5934 * This is a channel request we don't know
5935 * about, so we now either ignore the request
5936 * or respond with CHANNEL_FAILURE, depending
5937 * on want_reply.
5938 */
5939 if (want_reply) {
5940 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_FAILURE);
5941 ssh2_pkt_adduint32(ssh, c->remoteid);
5942 ssh2_pkt_send(ssh);
5943 }
5944 }
5945 } else if (ssh->pktin.type == SSH2_MSG_GLOBAL_REQUEST) {
5946 char *type;
5947 int typelen, want_reply;
5948
5949 ssh2_pkt_getstring(ssh, &type, &typelen);
5950 want_reply = ssh2_pkt_getbool(ssh);
5951
5952 /*
5953 * We currently don't support any global requests
5954 * at all, so we either ignore the request or
5955 * respond with REQUEST_FAILURE, depending on
5956 * want_reply.
5957 */
5958 if (want_reply) {
5959 ssh2_pkt_init(ssh, SSH2_MSG_REQUEST_FAILURE);
5960 ssh2_pkt_send(ssh);
5961 }
5962 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN) {
5963 char *type;
5964 int typelen;
5965 char *peeraddr;
5966 int peeraddrlen;
5967 int peerport;
5968 char *error = NULL;
5969 struct ssh_channel *c;
5970 unsigned remid, winsize, pktsize;
5971 ssh2_pkt_getstring(ssh, &type, &typelen);
5972 c = snew(struct ssh_channel);
5973 c->ssh = ssh;
5974
5975 remid = ssh2_pkt_getuint32(ssh);
5976 winsize = ssh2_pkt_getuint32(ssh);
5977 pktsize = ssh2_pkt_getuint32(ssh);
5978
5979 if (typelen == 3 && !memcmp(type, "x11", 3)) {
5980 char *addrstr;
5981
5982 ssh2_pkt_getstring(ssh, &peeraddr, &peeraddrlen);
5983 addrstr = snewn(peeraddrlen+1, char);
5984 memcpy(addrstr, peeraddr, peeraddrlen);
5985 peeraddr[peeraddrlen] = '\0';
5986 peerport = ssh2_pkt_getuint32(ssh);
5987
5988 if (!ssh->X11_fwd_enabled)
5989 error = "X11 forwarding is not enabled";
5990 else if (x11_init(&c->u.x11.s, ssh->cfg.x11_display, c,
5991 ssh->x11auth, addrstr, peerport,
5992 &ssh->cfg) != NULL) {
5993 error = "Unable to open an X11 connection";
5994 } else {
5995 c->type = CHAN_X11;
5996 }
5997
5998 sfree(addrstr);
5999 } else if (typelen == 15 &&
6000 !memcmp(type, "forwarded-tcpip", 15)) {
6001 struct ssh_rportfwd pf, *realpf;
6002 char *dummy;
6003 int dummylen;
6004 ssh2_pkt_getstring(ssh, &dummy, &dummylen);/* skip address */
6005 pf.sport = ssh2_pkt_getuint32(ssh);
6006 ssh2_pkt_getstring(ssh, &peeraddr, &peeraddrlen);
6007 peerport = ssh2_pkt_getuint32(ssh);
6008 realpf = find234(ssh->rportfwds, &pf, NULL);
6009 if (realpf == NULL) {
6010 error = "Remote port is not recognised";
6011 } else {
6012 const char *e = pfd_newconnect(&c->u.pfd.s,
6013 realpf->dhost,
6014 realpf->dport, c,
6015 &ssh->cfg);
6016 logeventf(ssh, "Received remote port open request"
6017 " for %s:%d", realpf->dhost, realpf->dport);
6018 if (e != NULL) {
6019 logeventf(ssh, "Port open failed: %s", e);
6020 error = "Port open failed";
6021 } else {
6022 logevent("Forwarded port opened successfully");
6023 c->type = CHAN_SOCKDATA;
6024 }
6025 }
6026 } else if (typelen == 22 &&
6027 !memcmp(type, "auth-agent@openssh.com", 3)) {
6028 if (!ssh->agentfwd_enabled)
6029 error = "Agent forwarding is not enabled";
6030 else {
6031 c->type = CHAN_AGENT; /* identify channel type */
6032 c->u.a.lensofar = 0;
6033 }
6034 } else {
6035 error = "Unsupported channel type requested";
6036 }
6037
6038 c->remoteid = remid;
6039 if (error) {
6040 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN_FAILURE);
6041 ssh2_pkt_adduint32(ssh, c->remoteid);
6042 ssh2_pkt_adduint32(ssh, SSH2_OPEN_CONNECT_FAILED);
6043 ssh2_pkt_addstring(ssh, error);
6044 ssh2_pkt_addstring(ssh, "en"); /* language tag */
6045 ssh2_pkt_send(ssh);
6046 sfree(c);
6047 } else {
6048 c->localid = alloc_channel_id(ssh);
6049 c->closes = 0;
6050 c->v.v2.locwindow = OUR_V2_WINSIZE;
6051 c->v.v2.remwindow = winsize;
6052 c->v.v2.remmaxpkt = pktsize;
6053 bufchain_init(&c->v.v2.outbuffer);
6054 add234(ssh->channels, c);
6055 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
6056 ssh2_pkt_adduint32(ssh, c->remoteid);
6057 ssh2_pkt_adduint32(ssh, c->localid);
6058 ssh2_pkt_adduint32(ssh, c->v.v2.locwindow);
6059 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
6060 ssh2_pkt_send(ssh);
6061 }
6062 } else {
6063 bombout(("Strange packet received: type %d", ssh->pktin.type));
6064 crStopV;
6065 }
6066 } else {
6067 /*
6068 * We have spare data. Add it to the channel buffer.
6069 */
6070 ssh2_add_channel_data(ssh->mainchan, (char *)in, inlen);
6071 s->try_send = TRUE;
6072 }
6073 if (s->try_send) {
6074 int i;
6075 struct ssh_channel *c;
6076 /*
6077 * Try to send data on all channels if we can.
6078 */
6079 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
6080 int bufsize;
6081 if (c->closes)
6082 continue; /* don't send on closing channels */
6083 bufsize = ssh2_try_send(c);
6084 if (bufsize == 0) {
6085 switch (c->type) {
6086 case CHAN_MAINSESSION:
6087 /* stdin need not receive an unthrottle
6088 * notification since it will be polled */
6089 break;
6090 case CHAN_X11:
6091 x11_unthrottle(c->u.x11.s);
6092 break;
6093 case CHAN_AGENT:
6094 /* agent sockets are request/response and need no
6095 * buffer management */
6096 break;
6097 case CHAN_SOCKDATA:
6098 pfd_unthrottle(c->u.pfd.s);
6099 break;
6100 }
6101 }
6102 }
6103 }
6104 }
6105
6106 crFinishV;
6107 }
6108
6109 /*
6110 * Handle the top-level SSH2 protocol.
6111 */
6112 static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
6113 {
6114 if (do_ssh2_transport(ssh, in, inlen, ispkt) == 0)
6115 return;
6116 do_ssh2_authconn(ssh, in, inlen, ispkt);
6117 }
6118
6119 /*
6120 * Called to set up the connection.
6121 *
6122 * Returns an error message, or NULL on success.
6123 */
6124 static const char *ssh_init(void *frontend_handle, void **backend_handle,
6125 Config *cfg,
6126 char *host, int port, char **realhost, int nodelay)
6127 {
6128 const char *p;
6129 Ssh ssh;
6130
6131 ssh = snew(struct ssh_tag);
6132 ssh->cfg = *cfg; /* STRUCTURE COPY */
6133 ssh->version = 0; /* when not ready yet */
6134 ssh->s = NULL;
6135 ssh->cipher = NULL;
6136 ssh->v1_cipher_ctx = NULL;
6137 ssh->crcda_ctx = NULL;
6138 ssh->cscipher = NULL;
6139 ssh->cs_cipher_ctx = NULL;
6140 ssh->sccipher = NULL;
6141 ssh->sc_cipher_ctx = NULL;
6142 ssh->csmac = NULL;
6143 ssh->cs_mac_ctx = NULL;
6144 ssh->scmac = NULL;
6145 ssh->sc_mac_ctx = NULL;
6146 ssh->cscomp = NULL;
6147 ssh->cs_comp_ctx = NULL;
6148 ssh->sccomp = NULL;
6149 ssh->sc_comp_ctx = NULL;
6150 ssh->kex = NULL;
6151 ssh->kex_ctx = NULL;
6152 ssh->hostkey = NULL;
6153 ssh->exitcode = -1;
6154 ssh->state = SSH_STATE_PREPACKET;
6155 ssh->size_needed = FALSE;
6156 ssh->eof_needed = FALSE;
6157 ssh->ldisc = NULL;
6158 ssh->logctx = NULL;
6159 {
6160 static const struct Packet empty = { 0, 0, NULL, NULL, 0 };
6161 ssh->pktin = ssh->pktout = empty;
6162 }
6163 ssh->deferred_send_data = NULL;
6164 ssh->deferred_len = 0;
6165 ssh->deferred_size = 0;
6166 ssh->fallback_cmd = 0;
6167 ssh->pkt_ctx = 0;
6168 ssh->x11auth = NULL;
6169 ssh->v1_compressing = FALSE;
6170 ssh->v2_outgoing_sequence = 0;
6171 ssh->ssh1_rdpkt_crstate = 0;
6172 ssh->ssh2_rdpkt_crstate = 0;
6173 ssh->do_ssh_init_crstate = 0;
6174 ssh->ssh_gotdata_crstate = 0;
6175 ssh->ssh1_protocol_crstate = 0;
6176 ssh->do_ssh1_login_crstate = 0;
6177 ssh->do_ssh2_transport_crstate = 0;
6178 ssh->do_ssh2_authconn_crstate = 0;
6179 ssh->do_ssh_init_state = NULL;
6180 ssh->do_ssh1_login_state = NULL;
6181 ssh->do_ssh2_transport_state = NULL;
6182 ssh->do_ssh2_authconn_state = NULL;
6183 ssh->mainchan = NULL;
6184 ssh->throttled_all = 0;
6185 ssh->v1_stdout_throttling = 0;
6186
6187 *backend_handle = ssh;
6188
6189 #ifdef MSCRYPTOAPI
6190 if (crypto_startup() == 0)
6191 return "Microsoft high encryption pack not installed!";
6192 #endif
6193
6194 ssh->frontend = frontend_handle;
6195 ssh->term_width = ssh->cfg.width;
6196 ssh->term_height = ssh->cfg.height;
6197
6198 ssh->channels = NULL;
6199 ssh->rportfwds = NULL;
6200
6201 ssh->send_ok = 0;
6202 ssh->editing = 0;
6203 ssh->echoing = 0;
6204 ssh->v1_throttle_count = 0;
6205 ssh->overall_bufsize = 0;
6206 ssh->fallback_cmd = 0;
6207
6208 ssh->protocol = NULL;
6209
6210 p = connect_to_host(ssh, host, port, realhost, nodelay);
6211 if (p != NULL)
6212 return p;
6213
6214 return NULL;
6215 }
6216
6217 static void ssh_free(void *handle)
6218 {
6219 Ssh ssh = (Ssh) handle;
6220 struct ssh_channel *c;
6221 struct ssh_rportfwd *pf;
6222
6223 if (ssh->v1_cipher_ctx)
6224 ssh->cipher->free_context(ssh->v1_cipher_ctx);
6225 if (ssh->cs_cipher_ctx)
6226 ssh->cscipher->free_context(ssh->cs_cipher_ctx);
6227 if (ssh->sc_cipher_ctx)
6228 ssh->sccipher->free_context(ssh->sc_cipher_ctx);
6229 if (ssh->cs_mac_ctx)
6230 ssh->csmac->free_context(ssh->cs_mac_ctx);
6231 if (ssh->sc_mac_ctx)
6232 ssh->scmac->free_context(ssh->sc_mac_ctx);
6233 if (ssh->cs_comp_ctx)
6234 ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
6235 if (ssh->sc_comp_ctx)
6236 ssh->sccomp->compress_cleanup(ssh->sc_comp_ctx);
6237 if (ssh->kex_ctx)
6238 dh_cleanup(ssh->kex_ctx);
6239 sfree(ssh->savedhost);
6240
6241 if (ssh->channels) {
6242 while ((c = delpos234(ssh->channels, 0)) != NULL) {
6243 switch (c->type) {
6244 case CHAN_X11:
6245 if (c->u.x11.s != NULL)
6246 x11_close(c->u.x11.s);
6247 break;
6248 case CHAN_SOCKDATA:
6249 if (c->u.pfd.s != NULL)
6250 pfd_close(c->u.pfd.s);
6251 break;
6252 }
6253 sfree(c);
6254 }
6255 freetree234(ssh->channels);
6256 }
6257
6258 if (ssh->rportfwds) {
6259 while ((pf = delpos234(ssh->rportfwds, 0)) != NULL)
6260 sfree(pf);
6261 freetree234(ssh->rportfwds);
6262 }
6263 sfree(ssh->deferred_send_data);
6264 if (ssh->x11auth)
6265 x11_free_auth(ssh->x11auth);
6266 sfree(ssh->do_ssh_init_state);
6267 sfree(ssh->do_ssh1_login_state);
6268 sfree(ssh->do_ssh2_transport_state);
6269 sfree(ssh->do_ssh2_authconn_state);
6270
6271 if (ssh->s)
6272 ssh_do_close(ssh);
6273 sfree(ssh);
6274 }
6275
6276 /*
6277 * Reconfigure the SSH backend.
6278 *
6279 * Currently, this function does nothing very useful. In future,
6280 * however, we could do some handy things with it. For example, we
6281 * could make the port forwarding configurer active in the Change
6282 * Settings box, and this routine could close down existing
6283 * forwardings and open up new ones in response to changes.
6284 */
6285 static void ssh_reconfig(void *handle, Config *cfg)
6286 {
6287 Ssh ssh = (Ssh) handle;
6288 ssh->cfg = *cfg; /* STRUCTURE COPY */
6289 }
6290
6291 /*
6292 * Called to send data down the Telnet connection.
6293 */
6294 static int ssh_send(void *handle, char *buf, int len)
6295 {
6296 Ssh ssh = (Ssh) handle;
6297
6298 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
6299 return 0;
6300
6301 ssh->protocol(ssh, (unsigned char *)buf, len, 0);
6302
6303 return ssh_sendbuffer(ssh);
6304 }
6305
6306 /*
6307 * Called to query the current amount of buffered stdin data.
6308 */
6309 static int ssh_sendbuffer(void *handle)
6310 {
6311 Ssh ssh = (Ssh) handle;
6312 int override_value;
6313
6314 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
6315 return 0;
6316
6317 /*
6318 * If the SSH socket itself has backed up, add the total backup
6319 * size on that to any individual buffer on the stdin channel.
6320 */
6321 override_value = 0;
6322 if (ssh->throttled_all)
6323 override_value = ssh->overall_bufsize;
6324
6325 if (ssh->version == 1) {
6326 return override_value;
6327 } else if (ssh->version == 2) {
6328 if (!ssh->mainchan || ssh->mainchan->closes > 0)
6329 return override_value;
6330 else
6331 return (override_value +
6332 bufchain_size(&ssh->mainchan->v.v2.outbuffer));
6333 }
6334
6335 return 0;
6336 }
6337
6338 /*
6339 * Called to set the size of the window from SSH's POV.
6340 */
6341 static void ssh_size(void *handle, int width, int height)
6342 {
6343 Ssh ssh = (Ssh) handle;
6344
6345 ssh->term_width = width;
6346 ssh->term_height = height;
6347
6348 switch (ssh->state) {
6349 case SSH_STATE_BEFORE_SIZE:
6350 case SSH_STATE_PREPACKET:
6351 case SSH_STATE_CLOSED:
6352 break; /* do nothing */
6353 case SSH_STATE_INTERMED:
6354 ssh->size_needed = TRUE; /* buffer for later */
6355 break;
6356 case SSH_STATE_SESSION:
6357 if (!ssh->cfg.nopty) {
6358 if (ssh->version == 1) {
6359 send_packet(ssh, SSH1_CMSG_WINDOW_SIZE,
6360 PKT_INT, ssh->term_height,
6361 PKT_INT, ssh->term_width,
6362 PKT_INT, 0, PKT_INT, 0, PKT_END);
6363 } else {
6364 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
6365 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
6366 ssh2_pkt_addstring(ssh, "window-change");
6367 ssh2_pkt_addbool(ssh, 0);
6368 ssh2_pkt_adduint32(ssh, ssh->term_width);
6369 ssh2_pkt_adduint32(ssh, ssh->term_height);
6370 ssh2_pkt_adduint32(ssh, 0);
6371 ssh2_pkt_adduint32(ssh, 0);
6372 ssh2_pkt_send(ssh);
6373 }
6374 }
6375 break;
6376 }
6377 }
6378
6379 /*
6380 * Return a list of the special codes that make sense in this
6381 * protocol.
6382 */
6383 static const struct telnet_special *ssh_get_specials(void *handle)
6384 {
6385 Ssh ssh = (Ssh) handle;
6386
6387 if (ssh->version == 1) {
6388 static const struct telnet_special ssh1_specials[] = {
6389 {"IGNORE message", TS_NOP},
6390 {NULL, 0}
6391 };
6392 return ssh1_specials;
6393 } else if (ssh->version == 2) {
6394 static const struct telnet_special ssh2_specials[] = {
6395 {"Break", TS_BRK},
6396 {"IGNORE message", TS_NOP},
6397 {NULL, 0}
6398 };
6399 return ssh2_specials;
6400 } else
6401 return NULL;
6402 }
6403
6404 /*
6405 * Send Telnet special codes. TS_EOF is useful for `plink', so you
6406 * can send an EOF and collect resulting output (e.g. `plink
6407 * hostname sort').
6408 */
6409 static void ssh_special(void *handle, Telnet_Special code)
6410 {
6411 Ssh ssh = (Ssh) handle;
6412
6413 if (code == TS_EOF) {
6414 if (ssh->state != SSH_STATE_SESSION) {
6415 /*
6416 * Buffer the EOF in case we are pre-SESSION, so we can
6417 * send it as soon as we reach SESSION.
6418 */
6419 if (code == TS_EOF)
6420 ssh->eof_needed = TRUE;
6421 return;
6422 }
6423 if (ssh->version == 1) {
6424 send_packet(ssh, SSH1_CMSG_EOF, PKT_END);
6425 } else {
6426 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_EOF);
6427 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
6428 ssh2_pkt_send(ssh);
6429 }
6430 logevent("Sent EOF message");
6431 } else if (code == TS_PING || code == TS_NOP) {
6432 if (ssh->state == SSH_STATE_CLOSED
6433 || ssh->state == SSH_STATE_PREPACKET) return;
6434 if (ssh->version == 1) {
6435 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE))
6436 send_packet(ssh, SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
6437 } else {
6438 ssh2_pkt_init(ssh, SSH2_MSG_IGNORE);
6439 ssh2_pkt_addstring_start(ssh);
6440 ssh2_pkt_send(ssh);
6441 }
6442 } else if (code == TS_BRK) {
6443 if (ssh->state == SSH_STATE_CLOSED
6444 || ssh->state == SSH_STATE_PREPACKET) return;
6445 if (ssh->version == 1) {
6446 logevent("Unable to send BREAK signal in SSH1");
6447 } else {
6448 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
6449 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
6450 ssh2_pkt_addstring(ssh, "break");
6451 ssh2_pkt_addbool(ssh, 0);
6452 ssh2_pkt_adduint32(ssh, 0); /* default break length */
6453 ssh2_pkt_send(ssh);
6454 }
6455 } else {
6456 /* do nothing */
6457 }
6458 }
6459
6460 void *new_sock_channel(void *handle, Socket s)
6461 {
6462 Ssh ssh = (Ssh) handle;
6463 struct ssh_channel *c;
6464 c = snew(struct ssh_channel);
6465 c->ssh = ssh;
6466
6467 if (c) {
6468 c->remoteid = -1; /* to be set when open confirmed */
6469 c->localid = alloc_channel_id(ssh);
6470 c->closes = 0;
6471 c->type = CHAN_SOCKDATA_DORMANT;/* identify channel type */
6472 c->u.pfd.s = s;
6473 bufchain_init(&c->v.v2.outbuffer);
6474 add234(ssh->channels, c);
6475 }
6476 return c;
6477 }
6478
6479 /*
6480 * This is called when stdout/stderr (the entity to which
6481 * from_backend sends data) manages to clear some backlog.
6482 */
6483 static void ssh_unthrottle(void *handle, int bufsize)
6484 {
6485 Ssh ssh = (Ssh) handle;
6486 if (ssh->version == 1) {
6487 if (ssh->v1_stdout_throttling && bufsize < SSH1_BUFFER_LIMIT) {
6488 ssh->v1_stdout_throttling = 0;
6489 ssh1_throttle(ssh, -1);
6490 }
6491 } else {
6492 if (ssh->mainchan && ssh->mainchan->closes == 0)
6493 ssh2_set_window(ssh->mainchan, OUR_V2_WINSIZE - bufsize);
6494 }
6495 }
6496
6497 void ssh_send_port_open(void *channel, char *hostname, int port, char *org)
6498 {
6499 struct ssh_channel *c = (struct ssh_channel *)channel;
6500 Ssh ssh = c->ssh;
6501
6502 logeventf(ssh, "Opening forwarded connection to %s:%d", hostname, port);
6503
6504 if (ssh->version == 1) {
6505 send_packet(ssh, SSH1_MSG_PORT_OPEN,
6506 PKT_INT, c->localid,
6507 PKT_STR, hostname,
6508 PKT_INT, port,
6509 //PKT_STR, <org:orgport>,
6510 PKT_END);
6511 } else {
6512 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN);
6513 ssh2_pkt_addstring(ssh, "direct-tcpip");
6514 ssh2_pkt_adduint32(ssh, c->localid);
6515 c->v.v2.locwindow = OUR_V2_WINSIZE;
6516 ssh2_pkt_adduint32(ssh, c->v.v2.locwindow);/* our window size */
6517 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
6518 ssh2_pkt_addstring(ssh, hostname);
6519 ssh2_pkt_adduint32(ssh, port);
6520 /*
6521 * We make up values for the originator data; partly it's
6522 * too much hassle to keep track, and partly I'm not
6523 * convinced the server should be told details like that
6524 * about my local network configuration.
6525 */
6526 ssh2_pkt_addstring(ssh, "client-side-connection");
6527 ssh2_pkt_adduint32(ssh, 0);
6528 ssh2_pkt_send(ssh);
6529 }
6530 }
6531
6532
6533 static Socket ssh_socket(void *handle)
6534 {
6535 Ssh ssh = (Ssh) handle;
6536 return ssh->s;
6537 }
6538
6539 static int ssh_sendok(void *handle)
6540 {
6541 Ssh ssh = (Ssh) handle;
6542 return ssh->send_ok;
6543 }
6544
6545 static int ssh_ldisc(void *handle, int option)
6546 {
6547 Ssh ssh = (Ssh) handle;
6548 if (option == LD_ECHO)
6549 return ssh->echoing;
6550 if (option == LD_EDIT)
6551 return ssh->editing;
6552 return FALSE;
6553 }
6554
6555 static void ssh_provide_ldisc(void *handle, void *ldisc)
6556 {
6557 Ssh ssh = (Ssh) handle;
6558 ssh->ldisc = ldisc;
6559 }
6560
6561 static void ssh_provide_logctx(void *handle, void *logctx)
6562 {
6563 Ssh ssh = (Ssh) handle;
6564 ssh->logctx = logctx;
6565 }
6566
6567 static int ssh_return_exitcode(void *handle)
6568 {
6569 Ssh ssh = (Ssh) handle;
6570 if (ssh->s != NULL)
6571 return -1;
6572 else
6573 return (ssh->exitcode >= 0 ? ssh->exitcode : 0);
6574 }
6575
6576 /*
6577 * Gross hack: pscp will try to start SFTP but fall back to scp1 if
6578 * that fails. This variable is the means by which scp.c can reach
6579 * into the SSH code and find out which one it got.
6580 */
6581 extern int ssh_fallback_cmd(void *handle)
6582 {
6583 Ssh ssh = (Ssh) handle;
6584 return ssh->fallback_cmd;
6585 }
6586
6587 Backend ssh_backend = {
6588 ssh_init,
6589 ssh_free,
6590 ssh_reconfig,
6591 ssh_send,
6592 ssh_sendbuffer,
6593 ssh_size,
6594 ssh_special,
6595 ssh_get_specials,
6596 ssh_socket,
6597 ssh_return_exitcode,
6598 ssh_sendok,
6599 ssh_ldisc,
6600 ssh_provide_ldisc,
6601 ssh_provide_logctx,
6602 ssh_unthrottle,
6603 22
6604 };
Local modifications for Simon Tatham's `PuTTY' SSH client and terminal emulator