projects / u / mdw / putty / blob
? search:


8cb5a5645bd4325913bc28e7d6b30af668276f5e
[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 sk_addr_free(addr);
2173 if ((err = sk_socket_error(ssh->s)) != NULL) {
2174 ssh->s = NULL;
2175 return err;
2176 }
2177
2178 return NULL;
2179 }
2180
2181 /*
2182 * Throttle or unthrottle the SSH connection.
2183 */
2184 static void ssh1_throttle(Ssh ssh, int adjust)
2185 {
2186 int old_count = ssh->v1_throttle_count;
2187 ssh->v1_throttle_count += adjust;
2188 assert(ssh->v1_throttle_count >= 0);
2189 if (ssh->v1_throttle_count && !old_count) {
2190 sk_set_frozen(ssh->s, 1);
2191 } else if (!ssh->v1_throttle_count && old_count) {
2192 sk_set_frozen(ssh->s, 0);
2193 }
2194 }
2195
2196 /*
2197 * Throttle or unthrottle _all_ local data streams (for when sends
2198 * on the SSH connection itself back up).
2199 */
2200 static void ssh_throttle_all(Ssh ssh, int enable, int bufsize)
2201 {
2202 int i;
2203 struct ssh_channel *c;
2204
2205 if (enable == ssh->throttled_all)
2206 return;
2207 ssh->throttled_all = enable;
2208 ssh->overall_bufsize = bufsize;
2209 if (!ssh->channels)
2210 return;
2211 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
2212 switch (c->type) {
2213 case CHAN_MAINSESSION:
2214 /*
2215 * This is treated separately, outside the switch.
2216 */
2217 break;
2218 case CHAN_X11:
2219 x11_override_throttle(c->u.x11.s, enable);
2220 break;
2221 case CHAN_AGENT:
2222 /* Agent channels require no buffer management. */
2223 break;
2224 case CHAN_SOCKDATA:
2225 pfd_override_throttle(c->u.pfd.s, enable);
2226 break;
2227 }
2228 }
2229 }
2230
2231 /*
2232 * Username and password input, abstracted off into routines
2233 * reusable in several places - even between SSH1 and SSH2.
2234 */
2235
2236 /* Set up a username or password input loop on a given buffer. */
2237 static void setup_userpass_input(Ssh ssh, char *buffer, int buflen, int echo)
2238 {
2239 ssh->userpass_input_buffer = buffer;
2240 ssh->userpass_input_buflen = buflen;
2241 ssh->userpass_input_bufpos = 0;
2242 ssh->userpass_input_echo = echo;
2243 }
2244
2245 /*
2246 * Process some terminal data in the course of username/password
2247 * input. Returns >0 for success (line of input returned in
2248 * buffer), <0 for failure (user hit ^C/^D, bomb out and exit), 0
2249 * for inconclusive (keep waiting for more input please).
2250 */
2251 static int process_userpass_input(Ssh ssh, unsigned char *in, int inlen)
2252 {
2253 char c;
2254
2255 while (inlen--) {
2256 switch (c = *in++) {
2257 case 10:
2258 case 13:
2259 ssh->userpass_input_buffer[ssh->userpass_input_bufpos] = 0;
2260 ssh->userpass_input_buffer[ssh->userpass_input_buflen-1] = 0;
2261 return +1;
2262 break;
2263 case 8:
2264 case 127:
2265 if (ssh->userpass_input_bufpos > 0) {
2266 if (ssh->userpass_input_echo)
2267 c_write_str(ssh, "\b \b");
2268 ssh->userpass_input_bufpos--;
2269 }
2270 break;
2271 case 21:
2272 case 27:
2273 while (ssh->userpass_input_bufpos > 0) {
2274 if (ssh->userpass_input_echo)
2275 c_write_str(ssh, "\b \b");
2276 ssh->userpass_input_bufpos--;
2277 }
2278 break;
2279 case 3:
2280 case 4:
2281 return -1;
2282 break;
2283 default:
2284 /*
2285 * This simplistic check for printability is disabled
2286 * when we're doing password input, because some people
2287 * have control characters in their passwords.o
2288 */
2289 if ((!ssh->userpass_input_echo ||
2290 (c >= ' ' && c <= '~') ||
2291 ((unsigned char) c >= 160))
2292 && ssh->userpass_input_bufpos < ssh->userpass_input_buflen-1) {
2293 ssh->userpass_input_buffer[ssh->userpass_input_bufpos++] = c;
2294 if (ssh->userpass_input_echo)
2295 c_write(ssh, &c, 1);
2296 }
2297 break;
2298 }
2299 }
2300 return 0;
2301 }
2302
2303 static void ssh_agent_callback(void *sshv, void *reply, int replylen)
2304 {
2305 Ssh ssh = (Ssh) sshv;
2306
2307 ssh->agent_response = reply;
2308 ssh->agent_response_len = replylen;
2309
2310 if (ssh->version == 1)
2311 do_ssh1_login(ssh, NULL, -1, 0);
2312 else
2313 do_ssh2_authconn(ssh, NULL, -1, 0);
2314 }
2315
2316 static void ssh_agentf_callback(void *cv, void *reply, int replylen)
2317 {
2318 struct ssh_channel *c = (struct ssh_channel *)cv;
2319 Ssh ssh = c->ssh;
2320 void *sentreply = reply;
2321
2322 if (!sentreply) {
2323 /* Fake SSH_AGENT_FAILURE. */
2324 sentreply = "\0\0\0\1\5";
2325 replylen = 5;
2326 }
2327 if (ssh->version == 2) {
2328 ssh2_add_channel_data(c, sentreply, replylen);
2329 ssh2_try_send(c);
2330 } else {
2331 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
2332 PKT_INT, c->remoteid,
2333 PKT_INT, replylen,
2334 PKT_DATA, sentreply, replylen,
2335 PKT_END);
2336 }
2337 if (reply)
2338 sfree(reply);
2339 }
2340
2341 /*
2342 * Handle the key exchange and user authentication phases.
2343 */
2344 static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
2345 {
2346 int i, j;
2347 unsigned char cookie[8];
2348 struct RSAKey servkey, hostkey;
2349 struct MD5Context md5c;
2350 struct do_ssh1_login_state {
2351 int len;
2352 unsigned char *rsabuf, *keystr1, *keystr2;
2353 unsigned long supported_ciphers_mask, supported_auths_mask;
2354 int tried_publickey, tried_agent;
2355 int tis_auth_refused, ccard_auth_refused;
2356 unsigned char session_id[16];
2357 int cipher_type;
2358 char username[100];
2359 void *publickey_blob;
2360 int publickey_bloblen;
2361 char password[100];
2362 char prompt[200];
2363 int pos;
2364 char c;
2365 int pwpkt_type;
2366 unsigned char request[5], *response, *p;
2367 int responselen;
2368 int keyi, nkeys;
2369 int authed;
2370 struct RSAKey key;
2371 Bignum challenge;
2372 char *commentp;
2373 int commentlen;
2374 };
2375 crState(do_ssh1_login_state);
2376
2377 crBegin(ssh->do_ssh1_login_crstate);
2378
2379 if (!ispkt)
2380 crWaitUntil(ispkt);
2381
2382 if (ssh->pktin.type != SSH1_SMSG_PUBLIC_KEY) {
2383 bombout(("Public key packet not received"));
2384 crStop(0);
2385 }
2386
2387 logevent("Received public keys");
2388
2389 memcpy(cookie, ssh->pktin.body, 8);
2390
2391 i = makekey(ssh->pktin.body + 8, &servkey, &s->keystr1, 0);
2392 j = makekey(ssh->pktin.body + 8 + i, &hostkey, &s->keystr2, 0);
2393
2394 /*
2395 * Log the host key fingerprint.
2396 */
2397 {
2398 char logmsg[80];
2399 logevent("Host key fingerprint is:");
2400 strcpy(logmsg, " ");
2401 hostkey.comment = NULL;
2402 rsa_fingerprint(logmsg + strlen(logmsg),
2403 sizeof(logmsg) - strlen(logmsg), &hostkey);
2404 logevent(logmsg);
2405 }
2406
2407 ssh->v1_remote_protoflags = GET_32BIT(ssh->pktin.body + 8 + i + j);
2408 s->supported_ciphers_mask = GET_32BIT(ssh->pktin.body + 12 + i + j);
2409 s->supported_auths_mask = GET_32BIT(ssh->pktin.body + 16 + i + j);
2410
2411 ssh->v1_local_protoflags =
2412 ssh->v1_remote_protoflags & SSH1_PROTOFLAGS_SUPPORTED;
2413 ssh->v1_local_protoflags |= SSH1_PROTOFLAG_SCREEN_NUMBER;
2414
2415 MD5Init(&md5c);
2416 MD5Update(&md5c, s->keystr2, hostkey.bytes);
2417 MD5Update(&md5c, s->keystr1, servkey.bytes);
2418 MD5Update(&md5c, ssh->pktin.body, 8);
2419 MD5Final(s->session_id, &md5c);
2420
2421 for (i = 0; i < 32; i++)
2422 ssh->session_key[i] = random_byte();
2423
2424 s->len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes);
2425
2426 s->rsabuf = snewn(s->len, unsigned char);
2427 if (!s->rsabuf)
2428 fatalbox("Out of memory");
2429
2430 /*
2431 * Verify the host key.
2432 */
2433 {
2434 /*
2435 * First format the key into a string.
2436 */
2437 int len = rsastr_len(&hostkey);
2438 char fingerprint[100];
2439 char *keystr = snewn(len, char);
2440 if (!keystr)
2441 fatalbox("Out of memory");
2442 rsastr_fmt(keystr, &hostkey);
2443 rsa_fingerprint(fingerprint, sizeof(fingerprint), &hostkey);
2444 verify_ssh_host_key(ssh->frontend,
2445 ssh->savedhost, ssh->savedport, "rsa", keystr,
2446 fingerprint);
2447 sfree(keystr);
2448 }
2449
2450 for (i = 0; i < 32; i++) {
2451 s->rsabuf[i] = ssh->session_key[i];
2452 if (i < 16)
2453 s->rsabuf[i] ^= s->session_id[i];
2454 }
2455
2456 if (hostkey.bytes > servkey.bytes) {
2457 rsaencrypt(s->rsabuf, 32, &servkey);
2458 rsaencrypt(s->rsabuf, servkey.bytes, &hostkey);
2459 } else {
2460 rsaencrypt(s->rsabuf, 32, &hostkey);
2461 rsaencrypt(s->rsabuf, hostkey.bytes, &servkey);
2462 }
2463
2464 logevent("Encrypted session key");
2465
2466 {
2467 int cipher_chosen = 0, warn = 0;
2468 char *cipher_string = NULL;
2469 int i;
2470 for (i = 0; !cipher_chosen && i < CIPHER_MAX; i++) {
2471 int next_cipher = ssh->cfg.ssh_cipherlist[i];
2472 if (next_cipher == CIPHER_WARN) {
2473 /* If/when we choose a cipher, warn about it */
2474 warn = 1;
2475 } else if (next_cipher == CIPHER_AES) {
2476 /* XXX Probably don't need to mention this. */
2477 logevent("AES not supported in SSH1, skipping");
2478 } else {
2479 switch (next_cipher) {
2480 case CIPHER_3DES: s->cipher_type = SSH_CIPHER_3DES;
2481 cipher_string = "3DES"; break;
2482 case CIPHER_BLOWFISH: s->cipher_type = SSH_CIPHER_BLOWFISH;
2483 cipher_string = "Blowfish"; break;
2484 case CIPHER_DES: s->cipher_type = SSH_CIPHER_DES;
2485 cipher_string = "single-DES"; break;
2486 }
2487 if (s->supported_ciphers_mask & (1 << s->cipher_type))
2488 cipher_chosen = 1;
2489 }
2490 }
2491 if (!cipher_chosen) {
2492 if ((s->supported_ciphers_mask & (1 << SSH_CIPHER_3DES)) == 0)
2493 bombout(("Server violates SSH 1 protocol by not "
2494 "supporting 3DES encryption"));
2495 else
2496 /* shouldn't happen */
2497 bombout(("No supported ciphers found"));
2498 crStop(0);
2499 }
2500
2501 /* Warn about chosen cipher if necessary. */
2502 if (warn)
2503 askcipher(ssh->frontend, cipher_string, 0);
2504 }
2505
2506 switch (s->cipher_type) {
2507 case SSH_CIPHER_3DES:
2508 logevent("Using 3DES encryption");
2509 break;
2510 case SSH_CIPHER_DES:
2511 logevent("Using single-DES encryption");
2512 break;
2513 case SSH_CIPHER_BLOWFISH:
2514 logevent("Using Blowfish encryption");
2515 break;
2516 }
2517
2518 send_packet(ssh, SSH1_CMSG_SESSION_KEY,
2519 PKT_CHAR, s->cipher_type,
2520 PKT_DATA, cookie, 8,
2521 PKT_CHAR, (s->len * 8) >> 8, PKT_CHAR, (s->len * 8) & 0xFF,
2522 PKT_DATA, s->rsabuf, s->len,
2523 PKT_INT, ssh->v1_local_protoflags, PKT_END);
2524
2525 logevent("Trying to enable encryption...");
2526
2527 sfree(s->rsabuf);
2528
2529 ssh->cipher = (s->cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 :
2530 s->cipher_type == SSH_CIPHER_DES ? &ssh_des :
2531 &ssh_3des);
2532 ssh->v1_cipher_ctx = ssh->cipher->make_context();
2533 ssh->cipher->sesskey(ssh->v1_cipher_ctx, ssh->session_key);
2534 logeventf(ssh, "Initialised %s encryption", ssh->cipher->text_name);
2535
2536 ssh->crcda_ctx = crcda_make_context();
2537 logevent("Installing CRC compensation attack detector");
2538
2539 crWaitUntil(ispkt);
2540
2541 if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
2542 bombout(("Encryption not successfully enabled"));
2543 crStop(0);
2544 }
2545
2546 logevent("Successfully started encryption");
2547
2548 fflush(stdout);
2549 {
2550 if ((flags & FLAG_INTERACTIVE) && !*ssh->cfg.username) {
2551 if (ssh_get_line && !ssh_getline_pw_only) {
2552 if (!ssh_get_line("login as: ",
2553 s->username, sizeof(s->username), FALSE)) {
2554 /*
2555 * get_line failed to get a username.
2556 * Terminate.
2557 */
2558 logevent("No username provided. Abandoning session.");
2559 ssh_closing((Plug)ssh, NULL, 0, 0);
2560 crStop(1);
2561 }
2562 } else {
2563 int ret; /* need not be kept over crReturn */
2564 c_write_str(ssh, "login as: ");
2565 ssh->send_ok = 1;
2566
2567 setup_userpass_input(ssh, s->username, sizeof(s->username), 1);
2568 do {
2569 crWaitUntil(!ispkt);
2570 ret = process_userpass_input(ssh, in, inlen);
2571 } while (ret == 0);
2572 if (ret < 0)
2573 cleanup_exit(0);
2574 c_write_str(ssh, "\r\n");
2575 }
2576 } else {
2577 strncpy(s->username, ssh->cfg.username, sizeof(s->username));
2578 s->username[sizeof(s->username)-1] = '\0';
2579 }
2580
2581 send_packet(ssh, SSH1_CMSG_USER, PKT_STR, s->username, PKT_END);
2582 {
2583 char userlog[22 + sizeof(s->username)];
2584 sprintf(userlog, "Sent username \"%s\"", s->username);
2585 logevent(userlog);
2586 if (flags & FLAG_INTERACTIVE &&
2587 (!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) {
2588 strcat(userlog, "\r\n");
2589 c_write_str(ssh, userlog);
2590 }
2591 }
2592 }
2593
2594 crWaitUntil(ispkt);
2595
2596 if ((ssh->remote_bugs & BUG_CHOKES_ON_RSA)) {
2597 /* We must not attempt PK auth. Pretend we've already tried it. */
2598 s->tried_publickey = s->tried_agent = 1;
2599 } else {
2600 s->tried_publickey = s->tried_agent = 0;
2601 }
2602 s->tis_auth_refused = s->ccard_auth_refused = 0;
2603 /* Load the public half of ssh->cfg.keyfile so we notice if it's in Pageant */
2604 if (!filename_is_null(ssh->cfg.keyfile)) {
2605 if (!rsakey_pubblob(&ssh->cfg.keyfile,
2606 &s->publickey_blob, &s->publickey_bloblen))
2607 s->publickey_blob = NULL;
2608 } else
2609 s->publickey_blob = NULL;
2610
2611 while (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2612 s->pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
2613
2614 if (agent_exists() && !s->tried_agent) {
2615 /*
2616 * Attempt RSA authentication using Pageant.
2617 */
2618 void *r;
2619
2620 s->authed = FALSE;
2621 s->tried_agent = 1;
2622 logevent("Pageant is running. Requesting keys.");
2623
2624 /* Request the keys held by the agent. */
2625 PUT_32BIT(s->request, 1);
2626 s->request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES;
2627 if (!agent_query(s->request, 5, &r, &s->responselen,
2628 ssh_agent_callback, ssh)) {
2629 do {
2630 crReturn(0);
2631 if (ispkt) {
2632 bombout(("Unexpected data from server while waiting"
2633 " for agent response"));
2634 crStop(0);
2635 }
2636 } while (ispkt || inlen > 0);
2637 r = ssh->agent_response;
2638 s->responselen = ssh->agent_response_len;
2639 }
2640 s->response = (unsigned char *) r;
2641 if (s->response && s->responselen >= 5 &&
2642 s->response[4] == SSH1_AGENT_RSA_IDENTITIES_ANSWER) {
2643 s->p = s->response + 5;
2644 s->nkeys = GET_32BIT(s->p);
2645 s->p += 4;
2646 {
2647 char buf[64];
2648 sprintf(buf, "Pageant has %d SSH1 keys", s->nkeys);
2649 logevent(buf);
2650 }
2651 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
2652 {
2653 char buf[64];
2654 sprintf(buf, "Trying Pageant key #%d", s->keyi);
2655 logevent(buf);
2656 }
2657 if (s->publickey_blob &&
2658 !memcmp(s->p, s->publickey_blob,
2659 s->publickey_bloblen)) {
2660 logevent("This key matches configured key file");
2661 s->tried_publickey = 1;
2662 }
2663 s->p += 4;
2664 s->p += ssh1_read_bignum(s->p, &s->key.exponent);
2665 s->p += ssh1_read_bignum(s->p, &s->key.modulus);
2666 s->commentlen = GET_32BIT(s->p);
2667 s->p += 4;
2668 s->commentp = (char *)s->p;
2669 s->p += s->commentlen;
2670 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
2671 PKT_BIGNUM, s->key.modulus, PKT_END);
2672 crWaitUntil(ispkt);
2673 if (ssh->pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
2674 logevent("Key refused");
2675 continue;
2676 }
2677 logevent("Received RSA challenge");
2678 ssh1_read_bignum(ssh->pktin.body, &s->challenge);
2679 {
2680 char *agentreq, *q, *ret;
2681 void *vret;
2682 int len, retlen;
2683 len = 1 + 4; /* message type, bit count */
2684 len += ssh1_bignum_length(s->key.exponent);
2685 len += ssh1_bignum_length(s->key.modulus);
2686 len += ssh1_bignum_length(s->challenge);
2687 len += 16; /* session id */
2688 len += 4; /* response format */
2689 agentreq = snewn(4 + len, char);
2690 PUT_32BIT(agentreq, len);
2691 q = agentreq + 4;
2692 *q++ = SSH1_AGENTC_RSA_CHALLENGE;
2693 PUT_32BIT(q, bignum_bitcount(s->key.modulus));
2694 q += 4;
2695 q += ssh1_write_bignum(q, s->key.exponent);
2696 q += ssh1_write_bignum(q, s->key.modulus);
2697 q += ssh1_write_bignum(q, s->challenge);
2698 memcpy(q, s->session_id, 16);
2699 q += 16;
2700 PUT_32BIT(q, 1); /* response format */
2701 if (!agent_query(agentreq, len + 4, &vret, &retlen,
2702 ssh_agent_callback, ssh)) {
2703 sfree(agentreq);
2704 do {
2705 crReturn(0);
2706 if (ispkt) {
2707 bombout(("Unexpected data from server"
2708 " while waiting for agent"
2709 " response"));
2710 crStop(0);
2711 }
2712 } while (ispkt || inlen > 0);
2713 vret = ssh->agent_response;
2714 retlen = ssh->agent_response_len;
2715 } else
2716 sfree(agentreq);
2717 ret = vret;
2718 if (ret) {
2719 if (ret[4] == SSH1_AGENT_RSA_RESPONSE) {
2720 logevent("Sending Pageant's response");
2721 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
2722 PKT_DATA, ret + 5, 16,
2723 PKT_END);
2724 sfree(ret);
2725 crWaitUntil(ispkt);
2726 if (ssh->pktin.type == SSH1_SMSG_SUCCESS) {
2727 logevent
2728 ("Pageant's response accepted");
2729 if (flags & FLAG_VERBOSE) {
2730 c_write_str(ssh, "Authenticated using"
2731 " RSA key \"");
2732 c_write(ssh, s->commentp,
2733 s->commentlen);
2734 c_write_str(ssh, "\" from agent\r\n");
2735 }
2736 s->authed = TRUE;
2737 } else
2738 logevent
2739 ("Pageant's response not accepted");
2740 } else {
2741 logevent
2742 ("Pageant failed to answer challenge");
2743 sfree(ret);
2744 }
2745 } else {
2746 logevent("No reply received from Pageant");
2747 }
2748 }
2749 freebn(s->key.exponent);
2750 freebn(s->key.modulus);
2751 freebn(s->challenge);
2752 if (s->authed)
2753 break;
2754 }
2755 }
2756 if (s->authed)
2757 break;
2758 }
2759 if (!filename_is_null(ssh->cfg.keyfile) && !s->tried_publickey)
2760 s->pwpkt_type = SSH1_CMSG_AUTH_RSA;
2761
2762 if (ssh->cfg.try_tis_auth &&
2763 (s->supported_auths_mask & (1 << SSH1_AUTH_TIS)) &&
2764 !s->tis_auth_refused) {
2765 s->pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
2766 logevent("Requested TIS authentication");
2767 send_packet(ssh, SSH1_CMSG_AUTH_TIS, PKT_END);
2768 crWaitUntil(ispkt);
2769 if (ssh->pktin.type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
2770 logevent("TIS authentication declined");
2771 if (flags & FLAG_INTERACTIVE)
2772 c_write_str(ssh, "TIS authentication refused.\r\n");
2773 s->tis_auth_refused = 1;
2774 continue;
2775 } else {
2776 int challengelen = GET_32BIT(ssh->pktin.body);
2777 logevent("Received TIS challenge");
2778 if (challengelen > sizeof(s->prompt) - 1)
2779 challengelen = sizeof(s->prompt) - 1;/* prevent overrun */
2780 memcpy(s->prompt, ssh->pktin.body + 4, challengelen);
2781 /* Prompt heuristic comes from OpenSSH */
2782 strncpy(s->prompt + challengelen,
2783 memchr(s->prompt, '\n', challengelen) ?
2784 "": "\r\nResponse: ",
2785 (sizeof s->prompt) - challengelen);
2786 s->prompt[(sizeof s->prompt) - 1] = '\0';
2787 }
2788 }
2789 if (ssh->cfg.try_tis_auth &&
2790 (s->supported_auths_mask & (1 << SSH1_AUTH_CCARD)) &&
2791 !s->ccard_auth_refused) {
2792 s->pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE;
2793 logevent("Requested CryptoCard authentication");
2794 send_packet(ssh, SSH1_CMSG_AUTH_CCARD, PKT_END);
2795 crWaitUntil(ispkt);
2796 if (ssh->pktin.type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
2797 logevent("CryptoCard authentication declined");
2798 c_write_str(ssh, "CryptoCard authentication refused.\r\n");
2799 s->ccard_auth_refused = 1;
2800 continue;
2801 } else {
2802 int challengelen = GET_32BIT(ssh->pktin.body);
2803 logevent("Received CryptoCard challenge");
2804 if (challengelen > sizeof(s->prompt) - 1)
2805 challengelen = sizeof(s->prompt) - 1;/* prevent overrun */
2806 memcpy(s->prompt, ssh->pktin.body + 4, challengelen);
2807 strncpy(s->prompt + challengelen,
2808 memchr(s->prompt, '\n', challengelen) ?
2809 "" : "\r\nResponse: ",
2810 sizeof(s->prompt) - challengelen);
2811 s->prompt[sizeof(s->prompt) - 1] = '\0';
2812 }
2813 }
2814 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
2815 sprintf(s->prompt, "%.90s@%.90s's password: ",
2816 s->username, ssh->savedhost);
2817 }
2818 if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) {
2819 char *comment = NULL;
2820 int type;
2821 char msgbuf[256];
2822 if (flags & FLAG_VERBOSE)
2823 c_write_str(ssh, "Trying public key authentication.\r\n");
2824 logeventf(ssh, "Trying public key \"%s\"",
2825 filename_to_str(&ssh->cfg.keyfile));
2826 type = key_type(&ssh->cfg.keyfile);
2827 if (type != SSH_KEYTYPE_SSH1) {
2828 sprintf(msgbuf, "Key is of wrong type (%s)",
2829 key_type_to_str(type));
2830 logevent(msgbuf);
2831 c_write_str(ssh, msgbuf);
2832 c_write_str(ssh, "\r\n");
2833 s->tried_publickey = 1;
2834 continue;
2835 }
2836 if (!rsakey_encrypted(&ssh->cfg.keyfile, &comment)) {
2837 if (flags & FLAG_VERBOSE)
2838 c_write_str(ssh, "No passphrase required.\r\n");
2839 goto tryauth;
2840 }
2841 sprintf(s->prompt, "Passphrase for key \"%.100s\": ", comment);
2842 sfree(comment);
2843 }
2844
2845 /*
2846 * Show password prompt, having first obtained it via a TIS
2847 * or CryptoCard exchange if we're doing TIS or CryptoCard
2848 * authentication.
2849 */
2850 if (ssh_get_line) {
2851 if (!ssh_get_line(s->prompt, s->password,
2852 sizeof(s->password), TRUE)) {
2853 /*
2854 * get_line failed to get a password (for example
2855 * because one was supplied on the command line
2856 * which has already failed to work). Terminate.
2857 */
2858 send_packet(ssh, SSH1_MSG_DISCONNECT,
2859 PKT_STR, "No more passwords available to try",
2860 PKT_END);
2861 logevent("Unable to authenticate");
2862 connection_fatal(ssh->frontend, "Unable to authenticate");
2863 ssh_closing((Plug)ssh, NULL, 0, 0);
2864 crStop(1);
2865 }
2866 } else {
2867 /* Prompt may have come from server. We've munged it a bit, so
2868 * we know it to be zero-terminated at least once. */
2869 int ret; /* need not be saved over crReturn */
2870 c_write_untrusted(ssh, s->prompt, strlen(s->prompt));
2871 s->pos = 0;
2872
2873 setup_userpass_input(ssh, s->password, sizeof(s->password), 0);
2874 do {
2875 crWaitUntil(!ispkt);
2876 ret = process_userpass_input(ssh, in, inlen);
2877 } while (ret == 0);
2878 if (ret < 0)
2879 cleanup_exit(0);
2880 c_write_str(ssh, "\r\n");
2881 }
2882
2883 tryauth:
2884 if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) {
2885 /*
2886 * Try public key authentication with the specified
2887 * key file.
2888 */
2889 s->tried_publickey = 1;
2890
2891 {
2892 int ret = loadrsakey(&ssh->cfg.keyfile, &s->key, s->password);
2893 if (ret == 0) {
2894 c_write_str(ssh, "Couldn't load private key from ");
2895 c_write_str(ssh, filename_to_str(&ssh->cfg.keyfile));
2896 c_write_str(ssh, ".\r\n");
2897 continue; /* go and try password */
2898 }
2899 if (ret == -1) {
2900 c_write_str(ssh, "Wrong passphrase.\r\n");
2901 s->tried_publickey = 0;
2902 continue; /* try again */
2903 }
2904 }
2905
2906 /*
2907 * Send a public key attempt.
2908 */
2909 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
2910 PKT_BIGNUM, s->key.modulus, PKT_END);
2911
2912 crWaitUntil(ispkt);
2913 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2914 c_write_str(ssh, "Server refused our public key.\r\n");
2915 continue; /* go and try password */
2916 }
2917 if (ssh->pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
2918 bombout(("Bizarre response to offer of public key"));
2919 crStop(0);
2920 }
2921
2922 {
2923 int i;
2924 unsigned char buffer[32];
2925 Bignum challenge, response;
2926
2927 ssh1_read_bignum(ssh->pktin.body, &challenge);
2928 response = rsadecrypt(challenge, &s->key);
2929 freebn(s->key.private_exponent);/* burn the evidence */
2930
2931 for (i = 0; i < 32; i++) {
2932 buffer[i] = bignum_byte(response, 31 - i);
2933 }
2934
2935 MD5Init(&md5c);
2936 MD5Update(&md5c, buffer, 32);
2937 MD5Update(&md5c, s->session_id, 16);
2938 MD5Final(buffer, &md5c);
2939
2940 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
2941 PKT_DATA, buffer, 16, PKT_END);
2942
2943 freebn(challenge);
2944 freebn(response);
2945 }
2946
2947 crWaitUntil(ispkt);
2948 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2949 if (flags & FLAG_VERBOSE)
2950 c_write_str(ssh, "Failed to authenticate with"
2951 " our public key.\r\n");
2952 continue; /* go and try password */
2953 } else if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
2954 bombout(("Bizarre response to RSA authentication response"));
2955 crStop(0);
2956 }
2957
2958 break; /* we're through! */
2959 } else {
2960 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
2961 /*
2962 * Defence against traffic analysis: we send a
2963 * whole bunch of packets containing strings of
2964 * different lengths. One of these strings is the
2965 * password, in a SSH1_CMSG_AUTH_PASSWORD packet.
2966 * The others are all random data in
2967 * SSH1_MSG_IGNORE packets. This way a passive
2968 * listener can't tell which is the password, and
2969 * hence can't deduce the password length.
2970 *
2971 * Anybody with a password length greater than 16
2972 * bytes is going to have enough entropy in their
2973 * password that a listener won't find it _that_
2974 * much help to know how long it is. So what we'll
2975 * do is:
2976 *
2977 * - if password length < 16, we send 15 packets
2978 * containing string lengths 1 through 15
2979 *
2980 * - otherwise, we let N be the nearest multiple
2981 * of 8 below the password length, and send 8
2982 * packets containing string lengths N through
2983 * N+7. This won't obscure the order of
2984 * magnitude of the password length, but it will
2985 * introduce a bit of extra uncertainty.
2986 *
2987 * A few servers (the old 1.2.18 through 1.2.22)
2988 * can't deal with SSH1_MSG_IGNORE. For these
2989 * servers, we need an alternative defence. We make
2990 * use of the fact that the password is interpreted
2991 * as a C string: so we can append a NUL, then some
2992 * random data.
2993 *
2994 * One server (a Cisco one) can deal with neither
2995 * SSH1_MSG_IGNORE _nor_ a padded password string.
2996 * For this server we are left with no defences
2997 * against password length sniffing.
2998 */
2999 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE)) {
3000 /*
3001 * The server can deal with SSH1_MSG_IGNORE, so
3002 * we can use the primary defence.
3003 */
3004 int bottom, top, pwlen, i;
3005 char *randomstr;
3006
3007 pwlen = strlen(s->password);
3008 if (pwlen < 16) {
3009 bottom = 0; /* zero length passwords are OK! :-) */
3010 top = 15;
3011 } else {
3012 bottom = pwlen & ~7;
3013 top = bottom + 7;
3014 }
3015
3016 assert(pwlen >= bottom && pwlen <= top);
3017
3018 randomstr = snewn(top + 1, char);
3019
3020 for (i = bottom; i <= top; i++) {
3021 if (i == pwlen)
3022 defer_packet(ssh, s->pwpkt_type,
3023 PKT_STR, s->password, PKT_END);
3024 else {
3025 for (j = 0; j < i; j++) {
3026 do {
3027 randomstr[j] = random_byte();
3028 } while (randomstr[j] == '\0');
3029 }
3030 randomstr[i] = '\0';
3031 defer_packet(ssh, SSH1_MSG_IGNORE,
3032 PKT_STR, randomstr, PKT_END);
3033 }
3034 }
3035 logevent("Sending password with camouflage packets");
3036 ssh_pkt_defersend(ssh);
3037 }
3038 else if (!(ssh->remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) {
3039 /*
3040 * The server can't deal with SSH1_MSG_IGNORE
3041 * but can deal with padded passwords, so we
3042 * can use the secondary defence.
3043 */
3044 char string[64];
3045 char *ss;
3046 int len;
3047
3048 len = strlen(s->password);
3049 if (len < sizeof(string)) {
3050 ss = string;
3051 strcpy(string, s->password);
3052 len++; /* cover the zero byte */
3053 while (len < sizeof(string)) {
3054 string[len++] = (char) random_byte();
3055 }
3056 } else {
3057 ss = s->password;
3058 }
3059 logevent("Sending length-padded password");
3060 send_packet(ssh, s->pwpkt_type, PKT_INT, len,
3061 PKT_DATA, ss, len, PKT_END);
3062 } else {
3063 /*
3064 * The server has _both_
3065 * BUG_CHOKES_ON_SSH1_IGNORE and
3066 * BUG_NEEDS_SSH1_PLAIN_PASSWORD. There is
3067 * therefore nothing we can do.
3068 */
3069 int len;
3070 len = strlen(s->password);
3071 logevent("Sending unpadded password");
3072 send_packet(ssh, s->pwpkt_type, PKT_INT, len,
3073 PKT_DATA, s->password, len, PKT_END);
3074 }
3075 } else {
3076 send_packet(ssh, s->pwpkt_type, PKT_STR, s->password, PKT_END);
3077 }
3078 }
3079 logevent("Sent password");
3080 memset(s->password, 0, strlen(s->password));
3081 crWaitUntil(ispkt);
3082 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3083 if (flags & FLAG_VERBOSE)
3084 c_write_str(ssh, "Access denied\r\n");
3085 logevent("Authentication refused");
3086 } else if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
3087 bombout(("Strange packet received, type %d", ssh->pktin.type));
3088 crStop(0);
3089 }
3090 }
3091
3092 logevent("Authentication successful");
3093
3094 crFinish(1);
3095 }
3096
3097 void sshfwd_close(struct ssh_channel *c)
3098 {
3099 Ssh ssh = c->ssh;
3100
3101 if (ssh->state != SSH_STATE_SESSION) {
3102 assert(ssh->state == SSH_STATE_CLOSED);
3103 return;
3104 }
3105
3106 if (c && !c->closes) {
3107 /*
3108 * If the channel's remoteid is -1, we have sent
3109 * CHANNEL_OPEN for this channel, but it hasn't even been
3110 * acknowledged by the server. So we must set a close flag
3111 * on it now, and then when the server acks the channel
3112 * open, we can close it then.
3113 */
3114 if (((int)c->remoteid) != -1) {
3115 if (ssh->version == 1) {
3116 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid,
3117 PKT_END);
3118 } else {
3119 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
3120 ssh2_pkt_adduint32(ssh, c->remoteid);
3121 ssh2_pkt_send(ssh);
3122 }
3123 }
3124 c->closes = 1; /* sent MSG_CLOSE */
3125 if (c->type == CHAN_X11) {
3126 c->u.x11.s = NULL;
3127 logevent("Forwarded X11 connection terminated");
3128 } else if (c->type == CHAN_SOCKDATA ||
3129 c->type == CHAN_SOCKDATA_DORMANT) {
3130 c->u.pfd.s = NULL;
3131 logevent("Forwarded port closed");
3132 }
3133 }
3134 }
3135
3136 int sshfwd_write(struct ssh_channel *c, char *buf, int len)
3137 {
3138 Ssh ssh = c->ssh;
3139
3140 if (ssh->state != SSH_STATE_SESSION) {
3141 assert(ssh->state == SSH_STATE_CLOSED);
3142 return 0;
3143 }
3144
3145 if (ssh->version == 1) {
3146 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
3147 PKT_INT, c->remoteid,
3148 PKT_INT, len, PKT_DATA, buf, len, PKT_END);
3149 /*
3150 * In SSH1 we can return 0 here - implying that forwarded
3151 * connections are never individually throttled - because
3152 * the only circumstance that can cause throttling will be
3153 * the whole SSH connection backing up, in which case
3154 * _everything_ will be throttled as a whole.
3155 */
3156 return 0;
3157 } else {
3158 ssh2_add_channel_data(c, buf, len);
3159 return ssh2_try_send(c);
3160 }
3161 }
3162
3163 void sshfwd_unthrottle(struct ssh_channel *c, int bufsize)
3164 {
3165 Ssh ssh = c->ssh;
3166
3167 if (ssh->state != SSH_STATE_SESSION) {
3168 assert(ssh->state == SSH_STATE_CLOSED);
3169 return;
3170 }
3171
3172 if (ssh->version == 1) {
3173 if (c->v.v1.throttling && bufsize < SSH1_BUFFER_LIMIT) {
3174 c->v.v1.throttling = 0;
3175 ssh1_throttle(ssh, -1);
3176 }
3177 } else {
3178 ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
3179 }
3180 }
3181
3182 static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
3183 {
3184 crBegin(ssh->ssh1_protocol_crstate);
3185
3186 random_init();
3187
3188 while (!do_ssh1_login(ssh, in, inlen, ispkt)) {
3189 crReturnV;
3190 }
3191 if (ssh->state == SSH_STATE_CLOSED)
3192 crReturnV;
3193
3194 if (ssh->cfg.agentfwd && agent_exists()) {
3195 logevent("Requesting agent forwarding");
3196 send_packet(ssh, SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END);
3197 do {
3198 crReturnV;
3199 } while (!ispkt);
3200 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3201 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3202 bombout(("Protocol confusion"));
3203 crStopV;
3204 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3205 logevent("Agent forwarding refused");
3206 } else {
3207 logevent("Agent forwarding enabled");
3208 ssh->agentfwd_enabled = TRUE;
3209 }
3210 }
3211
3212 if (ssh->cfg.x11_forward) {
3213 char proto[20], data[64];
3214 logevent("Requesting X11 forwarding");
3215 ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
3216 data, sizeof(data), ssh->cfg.x11_auth);
3217 x11_get_real_auth(ssh->x11auth, ssh->cfg.x11_display);
3218 if (ssh->v1_local_protoflags & SSH1_PROTOFLAG_SCREEN_NUMBER) {
3219 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
3220 PKT_STR, proto, PKT_STR, data,
3221 PKT_INT, x11_get_screen_number(ssh->cfg.x11_display),
3222 PKT_END);
3223 } else {
3224 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
3225 PKT_STR, proto, PKT_STR, data, PKT_END);
3226 }
3227 do {
3228 crReturnV;
3229 } while (!ispkt);
3230 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3231 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3232 bombout(("Protocol confusion"));
3233 crStopV;
3234 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3235 logevent("X11 forwarding refused");
3236 } else {
3237 logevent("X11 forwarding enabled");
3238 ssh->X11_fwd_enabled = TRUE;
3239 }
3240 }
3241
3242 {
3243 char type;
3244 int n;
3245 int sport,dport,sserv,dserv;
3246 char sports[256], dports[256], saddr[256], host[256];
3247
3248 ssh->rportfwds = newtree234(ssh_rportcmp_ssh1);
3249 /* Add port forwardings. */
3250 ssh->portfwd_strptr = ssh->cfg.portfwd;
3251 while (*ssh->portfwd_strptr) {
3252 type = *ssh->portfwd_strptr++;
3253 saddr[0] = '\0';
3254 n = 0;
3255 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != '\t') {
3256 if (*ssh->portfwd_strptr == ':') {
3257 /*
3258 * We've seen a colon in the middle of the
3259 * source port number. This means that
3260 * everything we've seen until now is the
3261 * source _address_, so we'll move it into
3262 * saddr and start sports from the beginning
3263 * again.
3264 */
3265 ssh->portfwd_strptr++;
3266 sports[n] = '\0';
3267 strcpy(saddr, sports);
3268 n = 0;
3269 }
3270 if (n < 255) sports[n++] = *ssh->portfwd_strptr++;
3271 }
3272 sports[n] = 0;
3273 if (type != 'D') {
3274 if (*ssh->portfwd_strptr == '\t')
3275 ssh->portfwd_strptr++;
3276 n = 0;
3277 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':') {
3278 if (n < 255) host[n++] = *ssh->portfwd_strptr++;
3279 }
3280 host[n] = 0;
3281 if (*ssh->portfwd_strptr == ':')
3282 ssh->portfwd_strptr++;
3283 n = 0;
3284 while (*ssh->portfwd_strptr) {
3285 if (n < 255) dports[n++] = *ssh->portfwd_strptr++;
3286 }
3287 dports[n] = 0;
3288 ssh->portfwd_strptr++;
3289 dport = atoi(dports);
3290 dserv = 0;
3291 if (dport == 0) {
3292 dserv = 1;
3293 dport = net_service_lookup(dports);
3294 if (!dport) {
3295 logeventf(ssh, "Service lookup failed for"
3296 " destination port \"%s\"", dports);
3297 }
3298 }
3299 } else {
3300 while (*ssh->portfwd_strptr) ssh->portfwd_strptr++;
3301 dport = dserv = -1;
3302 }
3303 sport = atoi(sports);
3304 sserv = 0;
3305 if (sport == 0) {
3306 sserv = 1;
3307 sport = net_service_lookup(sports);
3308 if (!sport) {
3309 logeventf(ssh, "Service lookup failed for source"
3310 " port \"%s\"", sports);
3311 }
3312 }
3313 if (sport && dport) {
3314 if (type == 'L') {
3315 pfd_addforward(host, dport, *saddr ? saddr : NULL,
3316 sport, ssh, &ssh->cfg);
3317 logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
3318 " forwarding to %s:%.*s%.*s%d%.*s",
3319 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
3320 (int)(*saddr?1:0), ":",
3321 (int)(sserv ? strlen(sports) : 0), sports,
3322 sserv, "(", sport, sserv, ")",
3323 host,
3324 (int)(dserv ? strlen(dports) : 0), dports,
3325 dserv, "(", dport, dserv, ")");
3326 } else if (type == 'D') {
3327 pfd_addforward(NULL, -1, *saddr ? saddr : NULL,
3328 sport, ssh, &ssh->cfg);
3329 logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
3330 " doing SOCKS dynamic forwarding",
3331 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
3332 (int)(*saddr?1:0), ":",
3333 (int)(sserv ? strlen(sports) : 0), sports,
3334 sserv, "(", sport, sserv, ")");
3335 } else {
3336 struct ssh_rportfwd *pf;
3337 pf = snew(struct ssh_rportfwd);
3338 strcpy(pf->dhost, host);
3339 pf->dport = dport;
3340 if (saddr) {
3341 logeventf(ssh,
3342 "SSH1 cannot handle source address spec \"%s:%d\"; ignoring",
3343 saddr, sport);
3344 }
3345 if (add234(ssh->rportfwds, pf) != pf) {
3346 logeventf(ssh,
3347 "Duplicate remote port forwarding to %s:%d",
3348 host, dport);
3349 sfree(pf);
3350 } else {
3351 logeventf(ssh, "Requesting remote port %.*s%.*s%d%.*s"
3352 " forward to %s:%.*s%.*s%d%.*s",
3353 (int)(sserv ? strlen(sports) : 0), sports,
3354 sserv, "(", sport, sserv, ")",
3355 host,
3356 (int)(dserv ? strlen(dports) : 0), dports,
3357 dserv, "(", dport, dserv, ")");
3358 send_packet(ssh, SSH1_CMSG_PORT_FORWARD_REQUEST,
3359 PKT_INT, sport,
3360 PKT_STR, host,
3361 PKT_INT, dport,
3362 PKT_END);
3363 do {
3364 crReturnV;
3365 } while (!ispkt);
3366 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3367 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3368 bombout(("Protocol confusion"));
3369 crStopV;
3370 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3371 c_write_str(ssh, "Server refused port"
3372 " forwarding\r\n");
3373 }
3374 logevent("Remote port forwarding enabled");
3375 }
3376 }
3377 }
3378 }
3379 }
3380
3381 if (!ssh->cfg.nopty) {
3382 send_packet(ssh, SSH1_CMSG_REQUEST_PTY,
3383 PKT_STR, ssh->cfg.termtype,
3384 PKT_INT, ssh->term_height,
3385 PKT_INT, ssh->term_width,
3386 PKT_INT, 0, PKT_INT, 0, PKT_CHAR, 0, PKT_END);
3387 ssh->state = SSH_STATE_INTERMED;
3388 do {
3389 crReturnV;
3390 } while (!ispkt);
3391 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3392 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3393 bombout(("Protocol confusion"));
3394 crStopV;
3395 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3396 c_write_str(ssh, "Server refused to allocate pty\r\n");
3397 ssh->editing = ssh->echoing = 1;
3398 }
3399 logevent("Allocated pty");
3400 } else {
3401 ssh->editing = ssh->echoing = 1;
3402 }
3403
3404 if (ssh->cfg.compression) {
3405 send_packet(ssh, SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END);
3406 do {
3407 crReturnV;
3408 } while (!ispkt);
3409 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3410 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3411 bombout(("Protocol confusion"));
3412 crStopV;
3413 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3414 c_write_str(ssh, "Server refused to compress\r\n");
3415 }
3416 logevent("Started compression");
3417 ssh->v1_compressing = TRUE;
3418 ssh->cs_comp_ctx = zlib_compress_init();
3419 logevent("Initialised zlib (RFC1950) compression");
3420 ssh->sc_comp_ctx = zlib_decompress_init();
3421 logevent("Initialised zlib (RFC1950) decompression");
3422 }
3423
3424 /*
3425 * Start the shell or command.
3426 *
3427 * Special case: if the first-choice command is an SSH2
3428 * subsystem (hence not usable here) and the second choice
3429 * exists, we fall straight back to that.
3430 */
3431 {
3432 char *cmd = ssh->cfg.remote_cmd_ptr;
3433
3434 if (ssh->cfg.ssh_subsys && ssh->cfg.remote_cmd_ptr2) {
3435 cmd = ssh->cfg.remote_cmd_ptr2;
3436 ssh->fallback_cmd = TRUE;
3437 }
3438 if (*cmd)
3439 send_packet(ssh, SSH1_CMSG_EXEC_CMD, PKT_STR, cmd, PKT_END);
3440 else
3441 send_packet(ssh, SSH1_CMSG_EXEC_SHELL, PKT_END);
3442 logevent("Started session");
3443 }
3444
3445 ssh->state = SSH_STATE_SESSION;
3446 if (ssh->size_needed)
3447 ssh_size(ssh, ssh->term_width, ssh->term_height);
3448 if (ssh->eof_needed)
3449 ssh_special(ssh, TS_EOF);
3450
3451 if (ssh->ldisc)
3452 ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */
3453 ssh->send_ok = 1;
3454 ssh->channels = newtree234(ssh_channelcmp);
3455 while (1) {
3456 crReturnV;
3457 if (ispkt) {
3458 if (ssh->pktin.type == SSH1_SMSG_STDOUT_DATA ||
3459 ssh->pktin.type == SSH1_SMSG_STDERR_DATA) {
3460 long len = GET_32BIT(ssh->pktin.body);
3461 int bufsize =
3462 from_backend(ssh->frontend,
3463 ssh->pktin.type == SSH1_SMSG_STDERR_DATA,
3464 (char *)(ssh->pktin.body) + 4, len);
3465 if (!ssh->v1_stdout_throttling && bufsize > SSH1_BUFFER_LIMIT) {
3466 ssh->v1_stdout_throttling = 1;
3467 ssh1_throttle(ssh, +1);
3468 }
3469 } else if (ssh->pktin.type == SSH1_MSG_DISCONNECT) {
3470 ssh_closing((Plug)ssh, NULL, 0, 0);
3471 logevent("Received disconnect request");
3472 crStopV;
3473 } else if (ssh->pktin.type == SSH1_SMSG_X11_OPEN) {
3474 /* Remote side is trying to open a channel to talk to our
3475 * X-Server. Give them back a local channel number. */
3476 struct ssh_channel *c;
3477
3478 logevent("Received X11 connect request");
3479 /* Refuse if X11 forwarding is disabled. */
3480 if (!ssh->X11_fwd_enabled) {
3481 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3482 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
3483 logevent("Rejected X11 connect request");
3484 } else {
3485 c = snew(struct ssh_channel);
3486 c->ssh = ssh;
3487
3488 if (x11_init(&c->u.x11.s, ssh->cfg.x11_display, c,
3489 ssh->x11auth, NULL, -1, &ssh->cfg) != NULL) {
3490 logevent("opening X11 forward connection failed");
3491 sfree(c);
3492 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3493 PKT_INT, GET_32BIT(ssh->pktin.body),
3494 PKT_END);
3495 } else {
3496 logevent
3497 ("opening X11 forward connection succeeded");
3498 c->remoteid = GET_32BIT(ssh->pktin.body);
3499 c->localid = alloc_channel_id(ssh);
3500 c->closes = 0;
3501 c->v.v1.throttling = 0;
3502 c->type = CHAN_X11; /* identify channel type */
3503 add234(ssh->channels, c);
3504 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3505 PKT_INT, c->remoteid, PKT_INT,
3506 c->localid, PKT_END);
3507 logevent("Opened X11 forward channel");
3508 }
3509 }
3510 } else if (ssh->pktin.type == SSH1_SMSG_AGENT_OPEN) {
3511 /* Remote side is trying to open a channel to talk to our
3512 * agent. Give them back a local channel number. */
3513 struct ssh_channel *c;
3514
3515 /* Refuse if agent forwarding is disabled. */
3516 if (!ssh->agentfwd_enabled) {
3517 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3518 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
3519 } else {
3520 c = snew(struct ssh_channel);
3521 c->ssh = ssh;
3522 c->remoteid = GET_32BIT(ssh->pktin.body);
3523 c->localid = alloc_channel_id(ssh);
3524 c->closes = 0;
3525 c->v.v1.throttling = 0;
3526 c->type = CHAN_AGENT; /* identify channel type */
3527 c->u.a.lensofar = 0;
3528 add234(ssh->channels, c);
3529 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3530 PKT_INT, c->remoteid, PKT_INT, c->localid,
3531 PKT_END);
3532 }
3533 } else if (ssh->pktin.type == SSH1_MSG_PORT_OPEN) {
3534 /* Remote side is trying to open a channel to talk to a
3535 * forwarded port. Give them back a local channel number. */
3536 struct ssh_channel *c;
3537 struct ssh_rportfwd pf;
3538 int hostsize, port;
3539 char host[256], buf[1024];
3540 char *p, *h;
3541 const char *e;
3542 c = snew(struct ssh_channel);
3543 c->ssh = ssh;
3544
3545 hostsize = GET_32BIT(ssh->pktin.body+4);
3546 for (h = host, p = (char *)(ssh->pktin.body+8);
3547 hostsize != 0; hostsize--) {
3548 if (h+1 < host+sizeof(host))
3549 *h++ = *p;
3550 p++;
3551 }
3552 *h = 0;
3553 port = GET_32BIT(p);
3554
3555 strcpy(pf.dhost, host);
3556 pf.dport = port;
3557
3558 if (find234(ssh->rportfwds, &pf, NULL) == NULL) {
3559 sprintf(buf, "Rejected remote port open request for %s:%d",
3560 host, port);
3561 logevent(buf);
3562 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3563 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
3564 } else {
3565 sprintf(buf, "Received remote port open request for %s:%d",
3566 host, port);
3567 logevent(buf);
3568 e = pfd_newconnect(&c->u.pfd.s, host, port, c, &ssh->cfg);
3569 if (e != NULL) {
3570 char buf[256];
3571 sprintf(buf, "Port open failed: %s", e);
3572 logevent(buf);
3573 sfree(c);
3574 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3575 PKT_INT, GET_32BIT(ssh->pktin.body),
3576 PKT_END);
3577 } else {
3578 c->remoteid = GET_32BIT(ssh->pktin.body);
3579 c->localid = alloc_channel_id(ssh);
3580 c->closes = 0;
3581 c->v.v1.throttling = 0;
3582 c->type = CHAN_SOCKDATA; /* identify channel type */
3583 add234(ssh->channels, c);
3584 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3585 PKT_INT, c->remoteid, PKT_INT,
3586 c->localid, PKT_END);
3587 logevent("Forwarded port opened successfully");
3588 }
3589 }
3590
3591 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_OPEN_CONFIRMATION) {
3592 unsigned int remoteid = GET_32BIT(ssh->pktin.body);
3593 unsigned int localid = GET_32BIT(ssh->pktin.body+4);
3594 struct ssh_channel *c;
3595
3596 c = find234(ssh->channels, &remoteid, ssh_channelfind);
3597 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
3598 c->remoteid = localid;
3599 c->type = CHAN_SOCKDATA;
3600 c->v.v1.throttling = 0;
3601 pfd_confirm(c->u.pfd.s);
3602 }
3603
3604 if (c && c->closes) {
3605 /*
3606 * We have a pending close on this channel,
3607 * which we decided on before the server acked
3608 * the channel open. So now we know the
3609 * remoteid, we can close it again.
3610 */
3611 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE,
3612 PKT_INT, c->remoteid, PKT_END);
3613 }
3614
3615 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_OPEN_FAILURE) {
3616 unsigned int remoteid = GET_32BIT(ssh->pktin.body);
3617 struct ssh_channel *c;
3618
3619 c = find234(ssh->channels, &remoteid, ssh_channelfind);
3620 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
3621 logevent("Forwarded connection refused by server");
3622 pfd_close(c->u.pfd.s);
3623 del234(ssh->channels, c);
3624 sfree(c);
3625 }
3626
3627 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ||
3628 ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION) {
3629 /* Remote side closes a channel. */
3630 unsigned i = GET_32BIT(ssh->pktin.body);
3631 struct ssh_channel *c;
3632 c = find234(ssh->channels, &i, ssh_channelfind);
3633 if (c && ((int)c->remoteid) != -1) {
3634 int closetype;
3635 closetype =
3636 (ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ? 1 : 2);
3637
3638 if ((c->closes == 0) && (c->type == CHAN_X11)) {
3639 logevent("Forwarded X11 connection terminated");
3640 assert(c->u.x11.s != NULL);
3641 x11_close(c->u.x11.s);
3642 c->u.x11.s = NULL;
3643 }
3644 if ((c->closes == 0) && (c->type == CHAN_SOCKDATA)) {
3645 logevent("Forwarded port closed");
3646 assert(c->u.pfd.s != NULL);
3647 pfd_close(c->u.pfd.s);
3648 c->u.pfd.s = NULL;
3649 }
3650
3651 c->closes |= (closetype << 2); /* seen this message */
3652 if (!(c->closes & closetype)) {
3653 send_packet(ssh, ssh->pktin.type, PKT_INT, c->remoteid,
3654 PKT_END);
3655 c->closes |= closetype; /* sent it too */
3656 }
3657
3658 if (c->closes == 15) {
3659 del234(ssh->channels, c);
3660 sfree(c);
3661 }
3662 } else {
3663 bombout(("Received CHANNEL_CLOSE%s for %s channel %d\n",
3664 ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ? "" :
3665 "_CONFIRMATION", c ? "half-open" : "nonexistent",
3666 i));
3667 crStopV;
3668 }
3669 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_DATA) {
3670 /* Data sent down one of our channels. */
3671 int i = GET_32BIT(ssh->pktin.body);
3672 int len = GET_32BIT(ssh->pktin.body + 4);
3673 unsigned char *p = ssh->pktin.body + 8;
3674 struct ssh_channel *c;
3675 c = find234(ssh->channels, &i, ssh_channelfind);
3676 if (c) {
3677 int bufsize = 0;
3678 switch (c->type) {
3679 case CHAN_X11:
3680 bufsize = x11_send(c->u.x11.s, (char *)p, len);
3681 break;
3682 case CHAN_SOCKDATA:
3683 bufsize = pfd_send(c->u.pfd.s, (char *)p, len);
3684 break;
3685 case CHAN_AGENT:
3686 /* Data for an agent message. Buffer it. */
3687 while (len > 0) {
3688 if (c->u.a.lensofar < 4) {
3689 int l = min(4 - c->u.a.lensofar, len);
3690 memcpy(c->u.a.msglen + c->u.a.lensofar, p,
3691 l);
3692 p += l;
3693 len -= l;
3694 c->u.a.lensofar += l;
3695 }
3696 if (c->u.a.lensofar == 4) {
3697 c->u.a.totallen =
3698 4 + GET_32BIT(c->u.a.msglen);
3699 c->u.a.message = snewn(c->u.a.totallen,
3700 unsigned char);
3701 memcpy(c->u.a.message, c->u.a.msglen, 4);
3702 }
3703 if (c->u.a.lensofar >= 4 && len > 0) {
3704 int l =
3705 min(c->u.a.totallen - c->u.a.lensofar,
3706 len);
3707 memcpy(c->u.a.message + c->u.a.lensofar, p,
3708 l);
3709 p += l;
3710 len -= l;
3711 c->u.a.lensofar += l;
3712 }
3713 if (c->u.a.lensofar == c->u.a.totallen) {
3714 void *reply;
3715 int replylen;
3716 if (agent_query(c->u.a.message,
3717 c->u.a.totallen,
3718 &reply, &replylen,
3719 ssh_agentf_callback, c))
3720 ssh_agentf_callback(c, reply, replylen);
3721 sfree(c->u.a.message);
3722 c->u.a.lensofar = 0;
3723 }
3724 }
3725 bufsize = 0; /* agent channels never back up */
3726 break;
3727 }
3728 if (!c->v.v1.throttling && bufsize > SSH1_BUFFER_LIMIT) {
3729 c->v.v1.throttling = 1;
3730 ssh1_throttle(ssh, +1);
3731 }
3732 }
3733 } else if (ssh->pktin.type == SSH1_SMSG_SUCCESS) {
3734 /* may be from EXEC_SHELL on some servers */
3735 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3736 /* may be from EXEC_SHELL on some servers
3737 * if no pty is available or in other odd cases. Ignore */
3738 } else if (ssh->pktin.type == SSH1_SMSG_EXIT_STATUS) {
3739 char buf[100];
3740 ssh->exitcode = GET_32BIT(ssh->pktin.body);
3741 sprintf(buf, "Server sent command exit status %d",
3742 ssh->exitcode);
3743 logevent(buf);
3744 send_packet(ssh, SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
3745 /*
3746 * In case `helpful' firewalls or proxies tack
3747 * extra human-readable text on the end of the
3748 * session which we might mistake for another
3749 * encrypted packet, we close the session once
3750 * we've sent EXIT_CONFIRMATION.
3751 */
3752 ssh_closing((Plug)ssh, NULL, 0, 0);
3753 crStopV;
3754 } else {
3755 bombout(("Strange packet received: type %d", ssh->pktin.type));
3756 crStopV;
3757 }
3758 } else {
3759 while (inlen > 0) {
3760 int len = min(inlen, 512);
3761 send_packet(ssh, SSH1_CMSG_STDIN_DATA,
3762 PKT_INT, len, PKT_DATA, in, len, PKT_END);
3763 in += len;
3764 inlen -= len;
3765 }
3766 }
3767 }
3768
3769 crFinishV;
3770 }
3771
3772 /*
3773 * Utility routine for decoding comma-separated strings in KEXINIT.
3774 */
3775 static int in_commasep_string(char *needle, char *haystack, int haylen)
3776 {
3777 int needlen;
3778 if (!needle || !haystack) /* protect against null pointers */
3779 return 0;
3780 needlen = strlen(needle);
3781 while (1) {
3782 /*
3783 * Is it at the start of the string?
3784 */
3785 if (haylen >= needlen && /* haystack is long enough */
3786 !memcmp(needle, haystack, needlen) && /* initial match */
3787 (haylen == needlen || haystack[needlen] == ',')
3788 /* either , or EOS follows */
3789 )
3790 return 1;
3791 /*
3792 * If not, search for the next comma and resume after that.
3793 * If no comma found, terminate.
3794 */
3795 while (haylen > 0 && *haystack != ',')
3796 haylen--, haystack++;
3797 if (haylen == 0)
3798 return 0;
3799 haylen--, haystack++; /* skip over comma itself */
3800 }
3801 }
3802
3803 /*
3804 * SSH2 key creation method.
3805 */
3806 static void ssh2_mkkey(Ssh ssh, Bignum K, unsigned char *H,
3807 unsigned char *sessid, char chr,
3808 unsigned char *keyspace)
3809 {
3810 SHA_State s;
3811 /* First 20 bytes. */
3812 SHA_Init(&s);
3813 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
3814 sha_mpint(&s, K);
3815 SHA_Bytes(&s, H, 20);
3816 SHA_Bytes(&s, &chr, 1);
3817 SHA_Bytes(&s, sessid, 20);
3818 SHA_Final(&s, keyspace);
3819 /* Next 20 bytes. */
3820 SHA_Init(&s);
3821 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
3822 sha_mpint(&s, K);
3823 SHA_Bytes(&s, H, 20);
3824 SHA_Bytes(&s, keyspace, 20);
3825 SHA_Final(&s, keyspace + 20);
3826 }
3827
3828 /*
3829 * Handle the SSH2 transport layer.
3830 */
3831 static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
3832 {
3833 struct do_ssh2_transport_state {
3834 int nbits, pbits, warn;
3835 Bignum p, g, e, f, K;
3836 int kex_init_value, kex_reply_value;
3837 const struct ssh_mac **maclist;
3838 int nmacs;
3839 const struct ssh2_cipher *cscipher_tobe;
3840 const struct ssh2_cipher *sccipher_tobe;
3841 const struct ssh_mac *csmac_tobe;
3842 const struct ssh_mac *scmac_tobe;
3843 const struct ssh_compress *cscomp_tobe;
3844 const struct ssh_compress *sccomp_tobe;
3845 char *hostkeydata, *sigdata, *keystr, *fingerprint;
3846 int hostkeylen, siglen;
3847 void *hkey; /* actual host key */
3848 unsigned char exchange_hash[20];
3849 int n_preferred_ciphers;
3850 const struct ssh2_ciphers *preferred_ciphers[CIPHER_MAX];
3851 const struct ssh_compress *preferred_comp;
3852 int first_kex;
3853 };
3854 crState(do_ssh2_transport_state);
3855
3856 crBegin(ssh->do_ssh2_transport_crstate);
3857
3858 s->cscipher_tobe = s->sccipher_tobe = NULL;
3859 s->csmac_tobe = s->scmac_tobe = NULL;
3860 s->cscomp_tobe = s->sccomp_tobe = NULL;
3861
3862 random_init();
3863 s->first_kex = 1;
3864
3865 {
3866 int i;
3867 /*
3868 * Set up the preferred ciphers. (NULL => warn below here)
3869 */
3870 s->n_preferred_ciphers = 0;
3871 for (i = 0; i < CIPHER_MAX; i++) {
3872 switch (ssh->cfg.ssh_cipherlist[i]) {
3873 case CIPHER_BLOWFISH:
3874 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_blowfish;
3875 break;
3876 case CIPHER_DES:
3877 if (ssh->cfg.ssh2_des_cbc) {
3878 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_des;
3879 }
3880 break;
3881 case CIPHER_3DES:
3882 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_3des;
3883 break;
3884 case CIPHER_AES:
3885 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_aes;
3886 break;
3887 case CIPHER_WARN:
3888 /* Flag for later. Don't bother if it's the last in
3889 * the list. */
3890 if (i < CIPHER_MAX - 1) {
3891 s->preferred_ciphers[s->n_preferred_ciphers++] = NULL;
3892 }
3893 break;
3894 }
3895 }
3896 }
3897
3898 /*
3899 * Set up preferred compression.
3900 */
3901 if (ssh->cfg.compression)
3902 s->preferred_comp = &ssh_zlib;
3903 else
3904 s->preferred_comp = &ssh_comp_none;
3905
3906 /*
3907 * Be prepared to work around the buggy MAC problem.
3908 */
3909 if (ssh->remote_bugs & BUG_SSH2_HMAC)
3910 s->maclist = buggymacs, s->nmacs = lenof(buggymacs);
3911 else
3912 s->maclist = macs, s->nmacs = lenof(macs);
3913
3914 begin_key_exchange:
3915 {
3916 int i, j, cipherstr_started;
3917
3918 /*
3919 * Construct and send our key exchange packet.
3920 */
3921 ssh2_pkt_init(ssh, SSH2_MSG_KEXINIT);
3922 for (i = 0; i < 16; i++)
3923 ssh2_pkt_addbyte(ssh, (unsigned char) random_byte());
3924 /* List key exchange algorithms. */
3925 ssh2_pkt_addstring_start(ssh);
3926 for (i = 0; i < lenof(kex_algs); i++) {
3927 if (kex_algs[i] == &ssh_diffiehellman_gex &&
3928 (ssh->remote_bugs & BUG_SSH2_DH_GEX))
3929 continue;
3930 ssh2_pkt_addstring_str(ssh, kex_algs[i]->name);
3931 if (i < lenof(kex_algs) - 1)
3932 ssh2_pkt_addstring_str(ssh, ",");
3933 }
3934 /* List server host key algorithms. */
3935 ssh2_pkt_addstring_start(ssh);
3936 for (i = 0; i < lenof(hostkey_algs); i++) {
3937 ssh2_pkt_addstring_str(ssh, hostkey_algs[i]->name);
3938 if (i < lenof(hostkey_algs) - 1)
3939 ssh2_pkt_addstring_str(ssh, ",");
3940 }
3941 /* List client->server encryption algorithms. */
3942 ssh2_pkt_addstring_start(ssh);
3943 cipherstr_started = 0;
3944 for (i = 0; i < s->n_preferred_ciphers; i++) {
3945 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3946 if (!c) continue; /* warning flag */
3947 for (j = 0; j < c->nciphers; j++) {
3948 if (cipherstr_started)
3949 ssh2_pkt_addstring_str(ssh, ",");
3950 ssh2_pkt_addstring_str(ssh, c->list[j]->name);
3951 cipherstr_started = 1;
3952 }
3953 }
3954 /* List server->client encryption algorithms. */
3955 ssh2_pkt_addstring_start(ssh);
3956 cipherstr_started = 0;
3957 for (i = 0; i < s->n_preferred_ciphers; i++) {
3958 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3959 if (!c) continue; /* warning flag */
3960 for (j = 0; j < c->nciphers; j++) {
3961 if (cipherstr_started)
3962 ssh2_pkt_addstring_str(ssh, ",");
3963 ssh2_pkt_addstring_str(ssh, c->list[j]->name);
3964 cipherstr_started = 1;
3965 }
3966 }
3967 /* List client->server MAC algorithms. */
3968 ssh2_pkt_addstring_start(ssh);
3969 for (i = 0; i < s->nmacs; i++) {
3970 ssh2_pkt_addstring_str(ssh, s->maclist[i]->name);
3971 if (i < s->nmacs - 1)
3972 ssh2_pkt_addstring_str(ssh, ",");
3973 }
3974 /* List server->client MAC algorithms. */
3975 ssh2_pkt_addstring_start(ssh);
3976 for (i = 0; i < s->nmacs; i++) {
3977 ssh2_pkt_addstring_str(ssh, s->maclist[i]->name);
3978 if (i < s->nmacs - 1)
3979 ssh2_pkt_addstring_str(ssh, ",");
3980 }
3981 /* List client->server compression algorithms. */
3982 ssh2_pkt_addstring_start(ssh);
3983 for (i = 0; i < lenof(compressions) + 1; i++) {
3984 const struct ssh_compress *c =
3985 i == 0 ? s->preferred_comp : compressions[i - 1];
3986 ssh2_pkt_addstring_str(ssh, c->name);
3987 if (i < lenof(compressions))
3988 ssh2_pkt_addstring_str(ssh, ",");
3989 }
3990 /* List server->client compression algorithms. */
3991 ssh2_pkt_addstring_start(ssh);
3992 for (i = 0; i < lenof(compressions) + 1; i++) {
3993 const struct ssh_compress *c =
3994 i == 0 ? s->preferred_comp : compressions[i - 1];
3995 ssh2_pkt_addstring_str(ssh, c->name);
3996 if (i < lenof(compressions))
3997 ssh2_pkt_addstring_str(ssh, ",");
3998 }
3999 /* List client->server languages. Empty list. */
4000 ssh2_pkt_addstring_start(ssh);
4001 /* List server->client languages. Empty list. */
4002 ssh2_pkt_addstring_start(ssh);
4003 /* First KEX packet does _not_ follow, because we're not that brave. */
4004 ssh2_pkt_addbool(ssh, FALSE);
4005 /* Reserved. */
4006 ssh2_pkt_adduint32(ssh, 0);
4007 }
4008
4009 ssh->exhash = ssh->exhashbase;
4010 sha_string(&ssh->exhash, ssh->pktout.data + 5, ssh->pktout.length - 5);
4011
4012 ssh2_pkt_send(ssh);
4013
4014 if (!ispkt)
4015 crWaitUntil(ispkt);
4016 if (ssh->pktin.length > 5)
4017 sha_string(&ssh->exhash, ssh->pktin.data + 5, ssh->pktin.length - 5);
4018
4019 /*
4020 * Now examine the other side's KEXINIT to see what we're up
4021 * to.
4022 */
4023 {
4024 char *str;
4025 int i, j, len;
4026
4027 if (ssh->pktin.type != SSH2_MSG_KEXINIT) {
4028 bombout(("expected key exchange packet from server"));
4029 crStop(0);
4030 }
4031 ssh->kex = NULL;
4032 ssh->hostkey = NULL;
4033 s->cscipher_tobe = NULL;
4034 s->sccipher_tobe = NULL;
4035 s->csmac_tobe = NULL;
4036 s->scmac_tobe = NULL;
4037 s->cscomp_tobe = NULL;
4038 s->sccomp_tobe = NULL;
4039 ssh->pktin.savedpos += 16; /* skip garbage cookie */
4040 ssh2_pkt_getstring(ssh, &str, &len); /* key exchange algorithms */
4041 for (i = 0; i < lenof(kex_algs); i++) {
4042 if (kex_algs[i] == &ssh_diffiehellman_gex &&
4043 (ssh->remote_bugs & BUG_SSH2_DH_GEX))
4044 continue;
4045 if (in_commasep_string(kex_algs[i]->name, str, len)) {
4046 ssh->kex = kex_algs[i];
4047 break;
4048 }
4049 }
4050 ssh2_pkt_getstring(ssh, &str, &len); /* host key algorithms */
4051 for (i = 0; i < lenof(hostkey_algs); i++) {
4052 if (in_commasep_string(hostkey_algs[i]->name, str, len)) {
4053 ssh->hostkey = hostkey_algs[i];
4054 break;
4055 }
4056 }
4057 ssh2_pkt_getstring(ssh, &str, &len); /* client->server cipher */
4058 s->warn = 0;
4059 for (i = 0; i < s->n_preferred_ciphers; i++) {
4060 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
4061 if (!c) {
4062 s->warn = 1;
4063 } else {
4064 for (j = 0; j < c->nciphers; j++) {
4065 if (in_commasep_string(c->list[j]->name, str, len)) {
4066 s->cscipher_tobe = c->list[j];
4067 break;
4068 }
4069 }
4070 }
4071 if (s->cscipher_tobe) {
4072 if (s->warn)
4073 askcipher(ssh->frontend, s->cscipher_tobe->name, 1);
4074 break;
4075 }
4076 }
4077 if (!s->cscipher_tobe) {
4078 bombout(("Couldn't agree a client-to-server cipher (available: %s)",
4079 str ? str : "(null)"));
4080 crStop(0);
4081 }
4082
4083 ssh2_pkt_getstring(ssh, &str, &len); /* server->client cipher */
4084 s->warn = 0;
4085 for (i = 0; i < s->n_preferred_ciphers; i++) {
4086 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
4087 if (!c) {
4088 s->warn = 1;
4089 } else {
4090 for (j = 0; j < c->nciphers; j++) {
4091 if (in_commasep_string(c->list[j]->name, str, len)) {
4092 s->sccipher_tobe = c->list[j];
4093 break;
4094 }
4095 }
4096 }
4097 if (s->sccipher_tobe) {
4098 if (s->warn)
4099 askcipher(ssh->frontend, s->sccipher_tobe->name, 2);
4100 break;
4101 }
4102 }
4103 if (!s->sccipher_tobe) {
4104 bombout(("Couldn't agree a server-to-client cipher (available: %s)",
4105 str ? str : "(null)"));
4106 crStop(0);
4107 }
4108
4109 ssh2_pkt_getstring(ssh, &str, &len); /* client->server mac */
4110 for (i = 0; i < s->nmacs; i++) {
4111 if (in_commasep_string(s->maclist[i]->name, str, len)) {
4112 s->csmac_tobe = s->maclist[i];
4113 break;
4114 }
4115 }
4116 ssh2_pkt_getstring(ssh, &str, &len); /* server->client mac */
4117 for (i = 0; i < s->nmacs; i++) {
4118 if (in_commasep_string(s->maclist[i]->name, str, len)) {
4119 s->scmac_tobe = s->maclist[i];
4120 break;
4121 }
4122 }
4123 ssh2_pkt_getstring(ssh, &str, &len); /* client->server compression */
4124 for (i = 0; i < lenof(compressions) + 1; i++) {
4125 const struct ssh_compress *c =
4126 i == 0 ? s->preferred_comp : compressions[i - 1];
4127 if (in_commasep_string(c->name, str, len)) {
4128 s->cscomp_tobe = c;
4129 break;
4130 }
4131 }
4132 ssh2_pkt_getstring(ssh, &str, &len); /* server->client compression */
4133 for (i = 0; i < lenof(compressions) + 1; i++) {
4134 const struct ssh_compress *c =
4135 i == 0 ? s->preferred_comp : compressions[i - 1];
4136 if (in_commasep_string(c->name, str, len)) {
4137 s->sccomp_tobe = c;
4138 break;
4139 }
4140 }
4141 }
4142
4143 /*
4144 * Work out the number of bits of key we will need from the key
4145 * exchange. We start with the maximum key length of either
4146 * cipher...
4147 */
4148 {
4149 int csbits, scbits;
4150
4151 csbits = s->cscipher_tobe->keylen;
4152 scbits = s->sccipher_tobe->keylen;
4153 s->nbits = (csbits > scbits ? csbits : scbits);
4154 }
4155 /* The keys only have 160-bit entropy, since they're based on
4156 * a SHA-1 hash. So cap the key size at 160 bits. */
4157 if (s->nbits > 160)
4158 s->nbits = 160;
4159
4160 /*
4161 * If we're doing Diffie-Hellman group exchange, start by
4162 * requesting a group.
4163 */
4164 if (ssh->kex == &ssh_diffiehellman_gex) {
4165 logevent("Doing Diffie-Hellman group exchange");
4166 ssh->pkt_ctx |= SSH2_PKTCTX_DHGEX;
4167 /*
4168 * Work out how big a DH group we will need to allow that
4169 * much data.
4170 */
4171 s->pbits = 512 << ((s->nbits - 1) / 64);
4172 ssh2_pkt_init(ssh, SSH2_MSG_KEX_DH_GEX_REQUEST);
4173 ssh2_pkt_adduint32(ssh, s->pbits);
4174 ssh2_pkt_send(ssh);
4175
4176 crWaitUntil(ispkt);
4177 if (ssh->pktin.type != SSH2_MSG_KEX_DH_GEX_GROUP) {
4178 bombout(("expected key exchange group packet from server"));
4179 crStop(0);
4180 }
4181 s->p = ssh2_pkt_getmp(ssh);
4182 s->g = ssh2_pkt_getmp(ssh);
4183 ssh->kex_ctx = dh_setup_group(s->p, s->g);
4184 s->kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT;
4185 s->kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY;
4186 } else {
4187 ssh->pkt_ctx |= SSH2_PKTCTX_DHGROUP1;
4188 ssh->kex_ctx = dh_setup_group1();
4189 s->kex_init_value = SSH2_MSG_KEXDH_INIT;
4190 s->kex_reply_value = SSH2_MSG_KEXDH_REPLY;
4191 }
4192
4193 logevent("Doing Diffie-Hellman key exchange");
4194 /*
4195 * Now generate and send e for Diffie-Hellman.
4196 */
4197 s->e = dh_create_e(ssh->kex_ctx, s->nbits * 2);
4198 ssh2_pkt_init(ssh, s->kex_init_value);
4199 ssh2_pkt_addmp(ssh, s->e);
4200 ssh2_pkt_send(ssh);
4201
4202 crWaitUntil(ispkt);
4203 if (ssh->pktin.type != s->kex_reply_value) {
4204 bombout(("expected key exchange reply packet from server"));
4205 crStop(0);
4206 }
4207 ssh2_pkt_getstring(ssh, &s->hostkeydata, &s->hostkeylen);
4208 s->f = ssh2_pkt_getmp(ssh);
4209 ssh2_pkt_getstring(ssh, &s->sigdata, &s->siglen);
4210
4211 s->K = dh_find_K(ssh->kex_ctx, s->f);
4212
4213 sha_string(&ssh->exhash, s->hostkeydata, s->hostkeylen);
4214 if (ssh->kex == &ssh_diffiehellman_gex) {
4215 sha_uint32(&ssh->exhash, s->pbits);
4216 sha_mpint(&ssh->exhash, s->p);
4217 sha_mpint(&ssh->exhash, s->g);
4218 }
4219 sha_mpint(&ssh->exhash, s->e);
4220 sha_mpint(&ssh->exhash, s->f);
4221 sha_mpint(&ssh->exhash, s->K);
4222 SHA_Final(&ssh->exhash, s->exchange_hash);
4223
4224 dh_cleanup(ssh->kex_ctx);
4225 ssh->kex_ctx = NULL;
4226
4227 #if 0
4228 debug(("Exchange hash is:\n"));
4229 dmemdump(s->exchange_hash, 20);
4230 #endif
4231
4232 s->hkey = ssh->hostkey->newkey(s->hostkeydata, s->hostkeylen);
4233 if (!s->hkey ||
4234 !ssh->hostkey->verifysig(s->hkey, s->sigdata, s->siglen,
4235 (char *)s->exchange_hash, 20)) {
4236 bombout(("Server's host key did not match the signature supplied"));
4237 crStop(0);
4238 }
4239
4240 /*
4241 * Authenticate remote host: verify host key. (We've already
4242 * checked the signature of the exchange hash.)
4243 */
4244 s->keystr = ssh->hostkey->fmtkey(s->hkey);
4245 s->fingerprint = ssh->hostkey->fingerprint(s->hkey);
4246 verify_ssh_host_key(ssh->frontend,
4247 ssh->savedhost, ssh->savedport, ssh->hostkey->keytype,
4248 s->keystr, s->fingerprint);
4249 if (s->first_kex) { /* don't bother logging this in rekeys */
4250 logevent("Host key fingerprint is:");
4251 logevent(s->fingerprint);
4252 }
4253 sfree(s->fingerprint);
4254 sfree(s->keystr);
4255 ssh->hostkey->freekey(s->hkey);
4256
4257 /*
4258 * Send SSH2_MSG_NEWKEYS.
4259 */
4260 ssh2_pkt_init(ssh, SSH2_MSG_NEWKEYS);
4261 ssh2_pkt_send(ssh);
4262
4263 /*
4264 * Expect SSH2_MSG_NEWKEYS from server.
4265 */
4266 crWaitUntil(ispkt);
4267 if (ssh->pktin.type != SSH2_MSG_NEWKEYS) {
4268 bombout(("expected new-keys packet from server"));
4269 crStop(0);
4270 }
4271
4272 /*
4273 * Create and initialise session keys.
4274 */
4275 if (ssh->cs_cipher_ctx)
4276 ssh->cscipher->free_context(ssh->cs_cipher_ctx);
4277 ssh->cscipher = s->cscipher_tobe;
4278 ssh->cs_cipher_ctx = ssh->cscipher->make_context();
4279
4280 if (ssh->sc_cipher_ctx)
4281 ssh->sccipher->free_context(ssh->sc_cipher_ctx);
4282 ssh->sccipher = s->sccipher_tobe;
4283 ssh->sc_cipher_ctx = ssh->sccipher->make_context();
4284
4285 if (ssh->cs_mac_ctx)
4286 ssh->csmac->free_context(ssh->cs_mac_ctx);
4287 ssh->csmac = s->csmac_tobe;
4288 ssh->cs_mac_ctx = ssh->csmac->make_context();
4289
4290 if (ssh->sc_mac_ctx)
4291 ssh->scmac->free_context(ssh->sc_mac_ctx);
4292 ssh->scmac = s->scmac_tobe;
4293 ssh->sc_mac_ctx = ssh->scmac->make_context();
4294
4295 if (ssh->cs_comp_ctx)
4296 ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
4297 ssh->cscomp = s->cscomp_tobe;
4298 ssh->cs_comp_ctx = ssh->cscomp->compress_init();
4299
4300 if (ssh->sc_comp_ctx)
4301 ssh->sccomp->decompress_cleanup(ssh->sc_comp_ctx);
4302 ssh->sccomp = s->sccomp_tobe;
4303 ssh->sc_comp_ctx = ssh->sccomp->decompress_init();
4304
4305 /*
4306 * Set IVs after keys. Here we use the exchange hash from the
4307 * _first_ key exchange.
4308 */
4309 {
4310 unsigned char keyspace[40];
4311 if (s->first_kex)
4312 memcpy(ssh->v2_session_id, s->exchange_hash,
4313 sizeof(s->exchange_hash));
4314 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'C',keyspace);
4315 ssh->cscipher->setkey(ssh->cs_cipher_ctx, keyspace);
4316 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'D',keyspace);
4317 ssh->sccipher->setkey(ssh->sc_cipher_ctx, keyspace);
4318 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'A',keyspace);
4319 ssh->cscipher->setiv(ssh->cs_cipher_ctx, keyspace);
4320 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'B',keyspace);
4321 ssh->sccipher->setiv(ssh->sc_cipher_ctx, keyspace);
4322 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'E',keyspace);
4323 ssh->csmac->setkey(ssh->cs_mac_ctx, keyspace);
4324 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'F',keyspace);
4325 ssh->scmac->setkey(ssh->sc_mac_ctx, keyspace);
4326 }
4327 logeventf(ssh, "Initialised %.200s client->server encryption",
4328 ssh->cscipher->text_name);
4329 logeventf(ssh, "Initialised %.200s server->client encryption",
4330 ssh->sccipher->text_name);
4331 if (ssh->cscomp->text_name)
4332 logeventf(ssh, "Initialised %s compression",
4333 ssh->cscomp->text_name);
4334 if (ssh->sccomp->text_name)
4335 logeventf(ssh, "Initialised %s decompression",
4336 ssh->sccomp->text_name);
4337
4338 /*
4339 * If this is the first key exchange phase, we must pass the
4340 * SSH2_MSG_NEWKEYS packet to the next layer, not because it
4341 * wants to see it but because it will need time to initialise
4342 * itself before it sees an actual packet. In subsequent key
4343 * exchange phases, we don't pass SSH2_MSG_NEWKEYS on, because
4344 * it would only confuse the layer above.
4345 */
4346 if (!s->first_kex) {
4347 crReturn(0);
4348 }
4349 s->first_kex = 0;
4350
4351 /*
4352 * Now we're encrypting. Begin returning 1 to the protocol main
4353 * function so that other things can run on top of the
4354 * transport. If we ever see a KEXINIT, we must go back to the
4355 * start.
4356 */
4357 while (!(ispkt && ssh->pktin.type == SSH2_MSG_KEXINIT)) {
4358 crReturn(1);
4359 }
4360 logevent("Server initiated key re-exchange");
4361 goto begin_key_exchange;
4362
4363 crFinish(1);
4364 }
4365
4366 /*
4367 * Add data to an SSH2 channel output buffer.
4368 */
4369 static void ssh2_add_channel_data(struct ssh_channel *c, char *buf,
4370 int len)
4371 {
4372 bufchain_add(&c->v.v2.outbuffer, buf, len);
4373 }
4374
4375 /*
4376 * Attempt to send data on an SSH2 channel.
4377 */
4378 static int ssh2_try_send(struct ssh_channel *c)
4379 {
4380 Ssh ssh = c->ssh;
4381
4382 while (c->v.v2.remwindow > 0 && bufchain_size(&c->v.v2.outbuffer) > 0) {
4383 int len;
4384 void *data;
4385 bufchain_prefix(&c->v.v2.outbuffer, &data, &len);
4386 if ((unsigned)len > c->v.v2.remwindow)
4387 len = c->v.v2.remwindow;
4388 if ((unsigned)len > c->v.v2.remmaxpkt)
4389 len = c->v.v2.remmaxpkt;
4390 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_DATA);
4391 ssh2_pkt_adduint32(ssh, c->remoteid);
4392 ssh2_pkt_addstring_start(ssh);
4393 ssh2_pkt_addstring_data(ssh, data, len);
4394 ssh2_pkt_send(ssh);
4395 bufchain_consume(&c->v.v2.outbuffer, len);
4396 c->v.v2.remwindow -= len;
4397 }
4398
4399 /*
4400 * After having sent as much data as we can, return the amount
4401 * still buffered.
4402 */
4403 return bufchain_size(&c->v.v2.outbuffer);
4404 }
4405
4406 /*
4407 * Potentially enlarge the window on an SSH2 channel.
4408 */
4409 static void ssh2_set_window(struct ssh_channel *c, unsigned newwin)
4410 {
4411 Ssh ssh = c->ssh;
4412
4413 /*
4414 * Never send WINDOW_ADJUST for a channel that the remote side
4415 * already thinks it's closed; there's no point, since it won't
4416 * be sending any more data anyway.
4417 */
4418 if (c->closes != 0)
4419 return;
4420
4421 if (newwin > c->v.v2.locwindow) {
4422 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST);
4423 ssh2_pkt_adduint32(ssh, c->remoteid);
4424 ssh2_pkt_adduint32(ssh, newwin - c->v.v2.locwindow);
4425 ssh2_pkt_send(ssh);
4426 c->v.v2.locwindow = newwin;
4427 }
4428 }
4429
4430 /*
4431 * Handle the SSH2 userauth and connection layers.
4432 */
4433 static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
4434 {
4435 struct do_ssh2_authconn_state {
4436 enum {
4437 AUTH_INVALID, AUTH_PUBLICKEY_AGENT, AUTH_PUBLICKEY_FILE,
4438 AUTH_PASSWORD,
4439 AUTH_KEYBOARD_INTERACTIVE
4440 } method;
4441 enum {
4442 AUTH_TYPE_NONE,
4443 AUTH_TYPE_PUBLICKEY,
4444 AUTH_TYPE_PUBLICKEY_OFFER_LOUD,
4445 AUTH_TYPE_PUBLICKEY_OFFER_QUIET,
4446 AUTH_TYPE_PASSWORD,
4447 AUTH_TYPE_KEYBOARD_INTERACTIVE,
4448 AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET
4449 } type;
4450 int gotit, need_pw, can_pubkey, can_passwd, can_keyb_inter;
4451 int tried_pubkey_config, tried_agent, tried_keyb_inter;
4452 int kbd_inter_running;
4453 int we_are_in;
4454 int num_prompts, curr_prompt, echo;
4455 char username[100];
4456 int got_username;
4457 char pwprompt[200];
4458 char password[100];
4459 void *publickey_blob;
4460 int publickey_bloblen;
4461 unsigned char request[5], *response, *p;
4462 int responselen;
4463 int keyi, nkeys;
4464 int authed;
4465 char *pkblob, *alg, *commentp;
4466 int pklen, alglen, commentlen;
4467 int siglen, retlen, len;
4468 char *q, *agentreq, *ret;
4469 int try_send;
4470 };
4471 crState(do_ssh2_authconn_state);
4472
4473 crBegin(ssh->do_ssh2_authconn_crstate);
4474
4475 /*
4476 * Request userauth protocol, and await a response to it.
4477 */
4478 ssh2_pkt_init(ssh, SSH2_MSG_SERVICE_REQUEST);
4479 ssh2_pkt_addstring(ssh, "ssh-userauth");
4480 ssh2_pkt_send(ssh);
4481 crWaitUntilV(ispkt);
4482 if (ssh->pktin.type != SSH2_MSG_SERVICE_ACCEPT) {
4483 bombout(("Server refused user authentication protocol"));
4484 crStopV;
4485 }
4486
4487 /*
4488 * We repeat this whole loop, including the username prompt,
4489 * until we manage a successful authentication. If the user
4490 * types the wrong _password_, they can be sent back to the
4491 * beginning to try another username, if this is configured on.
4492 * (If they specify a username in the config, they are never
4493 * asked, even if they do give a wrong password.)
4494 *
4495 * I think this best serves the needs of
4496 *
4497 * - the people who have no configuration, no keys, and just
4498 * want to try repeated (username,password) pairs until they
4499 * type both correctly
4500 *
4501 * - people who have keys and configuration but occasionally
4502 * need to fall back to passwords
4503 *
4504 * - people with a key held in Pageant, who might not have
4505 * logged in to a particular machine before; so they want to
4506 * type a username, and then _either_ their key will be
4507 * accepted, _or_ they will type a password. If they mistype
4508 * the username they will want to be able to get back and
4509 * retype it!
4510 */
4511 s->username[0] = '\0';
4512 s->got_username = FALSE;
4513 do {
4514 /*
4515 * Get a username.
4516 */
4517 if (s->got_username && !ssh->cfg.change_username) {
4518 /*
4519 * We got a username last time round this loop, and
4520 * with change_username turned off we don't try to get
4521 * it again.
4522 */
4523 } else if ((flags & FLAG_INTERACTIVE) && !*ssh->cfg.username) {
4524 if (ssh_get_line && !ssh_getline_pw_only) {
4525 if (!ssh_get_line("login as: ",
4526 s->username, sizeof(s->username), FALSE)) {
4527 /*
4528 * get_line failed to get a username.
4529 * Terminate.
4530 */
4531 logevent("No username provided. Abandoning session.");
4532 ssh_closing((Plug)ssh, NULL, 0, 0);
4533 crStopV;
4534 }
4535 } else {
4536 int ret; /* need not be saved across crReturn */
4537 c_write_str(ssh, "login as: ");
4538 ssh->send_ok = 1;
4539 setup_userpass_input(ssh, s->username, sizeof(s->username), 1);
4540 do {
4541 crWaitUntilV(!ispkt);
4542 ret = process_userpass_input(ssh, in, inlen);
4543 } while (ret == 0);
4544 if (ret < 0)
4545 cleanup_exit(0);
4546 c_write_str(ssh, "\r\n");
4547 }
4548 s->username[strcspn(s->username, "\n\r")] = '\0';
4549 } else {
4550 char *stuff;
4551 strncpy(s->username, ssh->cfg.username, sizeof(s->username));
4552 s->username[sizeof(s->username)-1] = '\0';
4553 if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
4554 stuff = dupprintf("Using username \"%s\".\r\n", s->username);
4555 c_write_str(ssh, stuff);
4556 sfree(stuff);
4557 }
4558 }
4559 s->got_username = TRUE;
4560
4561 /*
4562 * Send an authentication request using method "none": (a)
4563 * just in case it succeeds, and (b) so that we know what
4564 * authentication methods we can usefully try next.
4565 */
4566 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4567
4568 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4569 ssh2_pkt_addstring(ssh, s->username);
4570 ssh2_pkt_addstring(ssh, "ssh-connection");/* service requested */
4571 ssh2_pkt_addstring(ssh, "none"); /* method */
4572 ssh2_pkt_send(ssh);
4573 s->type = AUTH_TYPE_NONE;
4574 s->gotit = FALSE;
4575 s->we_are_in = FALSE;
4576
4577 s->tried_pubkey_config = FALSE;
4578 s->tried_agent = FALSE;
4579 s->tried_keyb_inter = FALSE;
4580 s->kbd_inter_running = FALSE;
4581 /* Load the pub half of ssh->cfg.keyfile so we notice if it's in Pageant */
4582 if (!filename_is_null(ssh->cfg.keyfile)) {
4583 int keytype;
4584 logeventf(ssh, "Reading private key file \"%.150s\"",
4585 filename_to_str(&ssh->cfg.keyfile));
4586 keytype = key_type(&ssh->cfg.keyfile);
4587 if (keytype == SSH_KEYTYPE_SSH2) {
4588 s->publickey_blob =
4589 ssh2_userkey_loadpub(&ssh->cfg.keyfile, NULL,
4590 &s->publickey_bloblen);
4591 } else {
4592 char *msgbuf;
4593 logeventf(ssh, "Unable to use this key file (%s)",
4594 key_type_to_str(keytype));
4595 msgbuf = dupprintf("Unable to use key file \"%.150s\""
4596 " (%s)\r\n",
4597 filename_to_str(&ssh->cfg.keyfile),
4598 key_type_to_str(keytype));
4599 c_write_str(ssh, msgbuf);
4600 sfree(msgbuf);
4601 s->publickey_blob = NULL;
4602 }
4603 } else
4604 s->publickey_blob = NULL;
4605
4606 while (1) {
4607 /*
4608 * Wait for the result of the last authentication request.
4609 */
4610 if (!s->gotit)
4611 crWaitUntilV(ispkt);
4612 while (ssh->pktin.type == SSH2_MSG_USERAUTH_BANNER) {
4613 char *banner;
4614 int size;
4615 /*
4616 * Don't show the banner if we're operating in
4617 * non-verbose non-interactive mode. (It's probably
4618 * a script, which means nobody will read the
4619 * banner _anyway_, and moreover the printing of
4620 * the banner will screw up processing on the
4621 * output of (say) plink.)
4622 */
4623 if (flags & (FLAG_VERBOSE | FLAG_INTERACTIVE)) {
4624 ssh2_pkt_getstring(ssh, &banner, &size);
4625 if (banner)
4626 c_write_untrusted(ssh, banner, size);
4627 }
4628 crWaitUntilV(ispkt);
4629 }
4630 if (ssh->pktin.type == SSH2_MSG_USERAUTH_SUCCESS) {
4631 logevent("Access granted");
4632 s->we_are_in = TRUE;
4633 break;
4634 }
4635
4636 if (s->kbd_inter_running &&
4637 ssh->pktin.type == SSH2_MSG_USERAUTH_INFO_REQUEST) {
4638 /*
4639 * This is either a further set-of-prompts packet
4640 * in keyboard-interactive authentication, or it's
4641 * the same one and we came back here with `gotit'
4642 * set. In the former case, we must reset the
4643 * curr_prompt variable.
4644 */
4645 if (!s->gotit)
4646 s->curr_prompt = 0;
4647 } else if (ssh->pktin.type != SSH2_MSG_USERAUTH_FAILURE) {
4648 bombout(("Strange packet received during authentication: type %d",
4649 ssh->pktin.type));
4650 crStopV;
4651 }
4652
4653 s->gotit = FALSE;
4654
4655 /*
4656 * OK, we're now sitting on a USERAUTH_FAILURE message, so
4657 * we can look at the string in it and know what we can
4658 * helpfully try next.
4659 */
4660 if (ssh->pktin.type == SSH2_MSG_USERAUTH_FAILURE) {
4661 char *methods;
4662 int methlen;
4663 ssh2_pkt_getstring(ssh, &methods, &methlen);
4664 s->kbd_inter_running = FALSE;
4665 if (!ssh2_pkt_getbool(ssh)) {
4666 /*
4667 * We have received an unequivocal Access
4668 * Denied. This can translate to a variety of
4669 * messages:
4670 *
4671 * - if we'd just tried "none" authentication,
4672 * it's not worth printing anything at all
4673 *
4674 * - if we'd just tried a public key _offer_,
4675 * the message should be "Server refused our
4676 * key" (or no message at all if the key
4677 * came from Pageant)
4678 *
4679 * - if we'd just tried anything else, the
4680 * message really should be "Access denied".
4681 *
4682 * Additionally, if we'd just tried password
4683 * authentication, we should break out of this
4684 * whole loop so as to go back to the username
4685 * prompt.
4686 */
4687 if (s->type == AUTH_TYPE_NONE) {
4688 /* do nothing */
4689 } else if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD ||
4690 s->type == AUTH_TYPE_PUBLICKEY_OFFER_QUIET) {
4691 if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD)
4692 c_write_str(ssh, "Server refused our key\r\n");
4693 logevent("Server refused public key");
4694 } else if (s->type==AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET) {
4695 /* server declined keyboard-interactive; ignore */
4696 } else {
4697 c_write_str(ssh, "Access denied\r\n");
4698 logevent("Access denied");
4699 if (s->type == AUTH_TYPE_PASSWORD) {
4700 s->we_are_in = FALSE;
4701 break;
4702 }
4703 }
4704 } else {
4705 c_write_str(ssh, "Further authentication required\r\n");
4706 logevent("Further authentication required");
4707 }
4708
4709 s->can_pubkey =
4710 in_commasep_string("publickey", methods, methlen);
4711 s->can_passwd =
4712 in_commasep_string("password", methods, methlen);
4713 s->can_keyb_inter = ssh->cfg.try_ki_auth &&
4714 in_commasep_string("keyboard-interactive", methods, methlen);
4715 }
4716
4717 s->method = 0;
4718 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4719
4720 /*
4721 * Most password/passphrase prompts will be
4722 * non-echoing, so we set this to 0 by default.
4723 * Exception is that some keyboard-interactive prompts
4724 * can be echoing, in which case we'll set this to 1.
4725 */
4726 s->echo = 0;
4727
4728 if (!s->method && s->can_pubkey &&
4729 agent_exists() && !s->tried_agent) {
4730 /*
4731 * Attempt public-key authentication using Pageant.
4732 */
4733 void *r;
4734 s->authed = FALSE;
4735
4736 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4737 ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
4738
4739 s->tried_agent = TRUE;
4740
4741 logevent("Pageant is running. Requesting keys.");
4742
4743 /* Request the keys held by the agent. */
4744 PUT_32BIT(s->request, 1);
4745 s->request[4] = SSH2_AGENTC_REQUEST_IDENTITIES;
4746 if (!agent_query(s->request, 5, &r, &s->responselen,
4747 ssh_agent_callback, ssh)) {
4748 do {
4749 crReturnV;
4750 if (ispkt) {
4751 bombout(("Unexpected data from server while"
4752 " waiting for agent response"));
4753 crStopV;
4754 }
4755 } while (ispkt || inlen > 0);
4756 r = ssh->agent_response;
4757 s->responselen = ssh->agent_response_len;
4758 }
4759 s->response = (unsigned char *) r;
4760 if (s->response && s->responselen >= 5 &&
4761 s->response[4] == SSH2_AGENT_IDENTITIES_ANSWER) {
4762 s->p = s->response + 5;
4763 s->nkeys = GET_32BIT(s->p);
4764 s->p += 4;
4765 {
4766 char buf[64];
4767 sprintf(buf, "Pageant has %d SSH2 keys", s->nkeys);
4768 logevent(buf);
4769 }
4770 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
4771 void *vret;
4772
4773 {
4774 char buf[64];
4775 sprintf(buf, "Trying Pageant key #%d", s->keyi);
4776 logevent(buf);
4777 }
4778 s->pklen = GET_32BIT(s->p);
4779 s->p += 4;
4780 if (s->publickey_blob &&
4781 s->pklen == s->publickey_bloblen &&
4782 !memcmp(s->p, s->publickey_blob,
4783 s->publickey_bloblen)) {
4784 logevent("This key matches configured key file");
4785 s->tried_pubkey_config = 1;
4786 }
4787 s->pkblob = (char *)s->p;
4788 s->p += s->pklen;
4789 s->alglen = GET_32BIT(s->pkblob);
4790 s->alg = s->pkblob + 4;
4791 s->commentlen = GET_32BIT(s->p);
4792 s->p += 4;
4793 s->commentp = (char *)s->p;
4794 s->p += s->commentlen;
4795 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4796 ssh2_pkt_addstring(ssh, s->username);
4797 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4798 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4799 ssh2_pkt_addbool(ssh, FALSE); /* no signature included */
4800 ssh2_pkt_addstring_start(ssh);
4801 ssh2_pkt_addstring_data(ssh, s->alg, s->alglen);
4802 ssh2_pkt_addstring_start(ssh);
4803 ssh2_pkt_addstring_data(ssh, s->pkblob, s->pklen);
4804 ssh2_pkt_send(ssh);
4805
4806 crWaitUntilV(ispkt);
4807 if (ssh->pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
4808 logevent("Key refused");
4809 continue;
4810 }
4811
4812 if (flags & FLAG_VERBOSE) {
4813 c_write_str(ssh, "Authenticating with "
4814 "public key \"");
4815 c_write(ssh, s->commentp, s->commentlen);
4816 c_write_str(ssh, "\" from agent\r\n");
4817 }
4818
4819 /*
4820 * Server is willing to accept the key.
4821 * Construct a SIGN_REQUEST.
4822 */
4823 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4824 ssh2_pkt_addstring(ssh, s->username);
4825 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4826 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4827 ssh2_pkt_addbool(ssh, TRUE);
4828 ssh2_pkt_addstring_start(ssh);
4829 ssh2_pkt_addstring_data(ssh, s->alg, s->alglen);
4830 ssh2_pkt_addstring_start(ssh);
4831 ssh2_pkt_addstring_data(ssh, s->pkblob, s->pklen);
4832
4833 s->siglen = ssh->pktout.length - 5 + 4 + 20;
4834 if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
4835 s->siglen -= 4;
4836 s->len = 1; /* message type */
4837 s->len += 4 + s->pklen; /* key blob */
4838 s->len += 4 + s->siglen; /* data to sign */
4839 s->len += 4; /* flags */
4840 s->agentreq = snewn(4 + s->len, char);
4841 PUT_32BIT(s->agentreq, s->len);
4842 s->q = s->agentreq + 4;
4843 *s->q++ = SSH2_AGENTC_SIGN_REQUEST;
4844 PUT_32BIT(s->q, s->pklen);
4845 s->q += 4;
4846 memcpy(s->q, s->pkblob, s->pklen);
4847 s->q += s->pklen;
4848 PUT_32BIT(s->q, s->siglen);
4849 s->q += 4;
4850 /* Now the data to be signed... */
4851 if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
4852 PUT_32BIT(s->q, 20);
4853 s->q += 4;
4854 }
4855 memcpy(s->q, ssh->v2_session_id, 20);
4856 s->q += 20;
4857 memcpy(s->q, ssh->pktout.data + 5,
4858 ssh->pktout.length - 5);
4859 s->q += ssh->pktout.length - 5;
4860 /* And finally the (zero) flags word. */
4861 PUT_32BIT(s->q, 0);
4862 if (!agent_query(s->agentreq, s->len + 4,
4863 &vret, &s->retlen,
4864 ssh_agent_callback, ssh)) {
4865 do {
4866 crReturnV;
4867 if (ispkt) {
4868 bombout(("Unexpected data from server"
4869 " while waiting for agent"
4870 " response"));
4871 crStopV;
4872 }
4873 } while (ispkt || inlen > 0);
4874 vret = ssh->agent_response;
4875 s->retlen = ssh->agent_response_len;
4876 }
4877 s->ret = vret;
4878 sfree(s->agentreq);
4879 if (s->ret) {
4880 if (s->ret[4] == SSH2_AGENT_SIGN_RESPONSE) {
4881 logevent("Sending Pageant's response");
4882 ssh2_add_sigblob(ssh, s->pkblob, s->pklen,
4883 s->ret + 9,
4884 GET_32BIT(s->ret + 5));
4885 ssh2_pkt_send(ssh);
4886 s->authed = TRUE;
4887 break;
4888 } else {
4889 logevent
4890 ("Pageant failed to answer challenge");
4891 sfree(s->ret);
4892 }
4893 }
4894 }
4895 if (s->authed)
4896 continue;
4897 }
4898 }
4899
4900 if (!s->method && s->can_pubkey && s->publickey_blob
4901 && !s->tried_pubkey_config) {
4902 unsigned char *pub_blob;
4903 char *algorithm, *comment;
4904 int pub_blob_len;
4905
4906 s->tried_pubkey_config = TRUE;
4907
4908 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4909 ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
4910
4911 /*
4912 * Try the public key supplied in the configuration.
4913 *
4914 * First, offer the public blob to see if the server is
4915 * willing to accept it.
4916 */
4917 pub_blob =
4918 (unsigned char *)ssh2_userkey_loadpub(&ssh->cfg.keyfile,
4919 &algorithm,
4920 &pub_blob_len);
4921 if (pub_blob) {
4922 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4923 ssh2_pkt_addstring(ssh, s->username);
4924 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4925 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4926 ssh2_pkt_addbool(ssh, FALSE); /* no signature included */
4927 ssh2_pkt_addstring(ssh, algorithm);
4928 ssh2_pkt_addstring_start(ssh);
4929 ssh2_pkt_addstring_data(ssh, (char *)pub_blob,
4930 pub_blob_len);
4931 ssh2_pkt_send(ssh);
4932 logevent("Offered public key"); /* FIXME */
4933
4934 crWaitUntilV(ispkt);
4935 if (ssh->pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
4936 s->gotit = TRUE;
4937 s->type = AUTH_TYPE_PUBLICKEY_OFFER_LOUD;
4938 continue; /* key refused; give up on it */
4939 }
4940
4941 logevent("Offer of public key accepted");
4942 /*
4943 * Actually attempt a serious authentication using
4944 * the key.
4945 */
4946 if (ssh2_userkey_encrypted(&ssh->cfg.keyfile, &comment)) {
4947 sprintf(s->pwprompt,
4948 "Passphrase for key \"%.100s\": ",
4949 comment);
4950 s->need_pw = TRUE;
4951 } else {
4952 s->need_pw = FALSE;
4953 }
4954 c_write_str(ssh, "Authenticating with public key \"");
4955 c_write_str(ssh, comment);
4956 c_write_str(ssh, "\"\r\n");
4957 s->method = AUTH_PUBLICKEY_FILE;
4958 }
4959 }
4960
4961 if (!s->method && s->can_keyb_inter && !s->tried_keyb_inter) {
4962 s->method = AUTH_KEYBOARD_INTERACTIVE;
4963 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
4964 s->tried_keyb_inter = TRUE;
4965
4966 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4967 ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;
4968
4969 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4970 ssh2_pkt_addstring(ssh, s->username);
4971 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4972 ssh2_pkt_addstring(ssh, "keyboard-interactive"); /* method */
4973 ssh2_pkt_addstring(ssh, ""); /* lang */
4974 ssh2_pkt_addstring(ssh, "");
4975 ssh2_pkt_send(ssh);
4976
4977 crWaitUntilV(ispkt);
4978 if (ssh->pktin.type != SSH2_MSG_USERAUTH_INFO_REQUEST) {
4979 if (ssh->pktin.type == SSH2_MSG_USERAUTH_FAILURE)
4980 s->gotit = TRUE;
4981 logevent("Keyboard-interactive authentication refused");
4982 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET;
4983 continue;
4984 }
4985
4986 s->kbd_inter_running = TRUE;
4987 s->curr_prompt = 0;
4988 }
4989
4990 if (s->kbd_inter_running) {
4991 s->method = AUTH_KEYBOARD_INTERACTIVE;
4992 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
4993 s->tried_keyb_inter = TRUE;
4994
4995 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4996 ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;
4997
4998 if (s->curr_prompt == 0) {
4999 /*
5000 * We've got a fresh USERAUTH_INFO_REQUEST.
5001 * Display header data, and start going through
5002 * the prompts.
5003 */
5004 char *name, *inst, *lang;
5005 int name_len, inst_len, lang_len;
5006
5007 ssh2_pkt_getstring(ssh, &name, &name_len);
5008 ssh2_pkt_getstring(ssh, &inst, &inst_len);
5009 ssh2_pkt_getstring(ssh, &lang, &lang_len);
5010 if (name_len > 0) {
5011 c_write_untrusted(ssh, name, name_len);
5012 c_write_str(ssh, "\r\n");
5013 }
5014 if (inst_len > 0) {
5015 c_write_untrusted(ssh, inst, inst_len);
5016 c_write_str(ssh, "\r\n");
5017 }
5018 s->num_prompts = ssh2_pkt_getuint32(ssh);
5019 }
5020
5021 /*
5022 * If there are prompts remaining in the packet,
5023 * display one and get a response.
5024 */
5025 if (s->curr_prompt < s->num_prompts) {
5026 char *prompt;
5027 int prompt_len;
5028
5029 ssh2_pkt_getstring(ssh, &prompt, &prompt_len);
5030 if (prompt_len > 0) {
5031 strncpy(s->pwprompt, prompt, sizeof(s->pwprompt));
5032 s->pwprompt[prompt_len < sizeof(s->pwprompt) ?
5033 prompt_len : sizeof(s->pwprompt)-1] = '\0';
5034 } else {
5035 strcpy(s->pwprompt,
5036 "<server failed to send prompt>: ");
5037 }
5038 s->echo = ssh2_pkt_getbool(ssh);
5039 s->need_pw = TRUE;
5040 } else
5041 s->need_pw = FALSE;
5042 }
5043
5044 if (!s->method && s->can_passwd) {
5045 s->method = AUTH_PASSWORD;
5046 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
5047 ssh->pkt_ctx |= SSH2_PKTCTX_PASSWORD;
5048 sprintf(s->pwprompt, "%.90s@%.90s's password: ", s->username,
5049 ssh->savedhost);
5050 s->need_pw = TRUE;
5051 }
5052
5053 if (s->need_pw) {
5054 if (ssh_get_line) {
5055 if (!ssh_get_line(s->pwprompt, s->password,
5056 sizeof(s->password), TRUE)) {
5057 /*
5058 * get_line failed to get a password (for
5059 * example because one was supplied on the
5060 * command line which has already failed to
5061 * work). Terminate.
5062 */
5063 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5064 ssh2_pkt_adduint32(ssh,SSH2_DISCONNECT_BY_APPLICATION);
5065 ssh2_pkt_addstring(ssh, "No more passwords available"
5066 " to try");
5067 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5068 ssh2_pkt_send(ssh);
5069 logevent("Unable to authenticate");
5070 connection_fatal(ssh->frontend,
5071 "Unable to authenticate");
5072 ssh_closing((Plug)ssh, NULL, 0, 0);
5073 crStopV;
5074 }
5075 } else {
5076 int ret; /* need not be saved across crReturn */
5077 c_write_untrusted(ssh, s->pwprompt, strlen(s->pwprompt));
5078 ssh->send_ok = 1;
5079
5080 setup_userpass_input(ssh, s->password,
5081 sizeof(s->password), s->echo);
5082 do {
5083 crWaitUntilV(!ispkt);
5084 ret = process_userpass_input(ssh, in, inlen);
5085 } while (ret == 0);
5086 if (ret < 0)
5087 cleanup_exit(0);
5088 c_write_str(ssh, "\r\n");
5089 }
5090 }
5091
5092 if (s->method == AUTH_PUBLICKEY_FILE) {
5093 /*
5094 * We have our passphrase. Now try the actual authentication.
5095 */
5096 struct ssh2_userkey *key;
5097
5098 key = ssh2_load_userkey(&ssh->cfg.keyfile, s->password);
5099 if (key == SSH2_WRONG_PASSPHRASE || key == NULL) {
5100 if (key == SSH2_WRONG_PASSPHRASE) {
5101 c_write_str(ssh, "Wrong passphrase\r\n");
5102 s->tried_pubkey_config = FALSE;
5103 } else {
5104 c_write_str(ssh, "Unable to load private key\r\n");
5105 s->tried_pubkey_config = TRUE;
5106 }
5107 /* Send a spurious AUTH_NONE to return to the top. */
5108 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
5109 ssh2_pkt_addstring(ssh, s->username);
5110 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
5111 ssh2_pkt_addstring(ssh, "none"); /* method */
5112 ssh2_pkt_send(ssh);
5113 s->type = AUTH_TYPE_NONE;
5114 } else {
5115 unsigned char *pkblob, *sigblob, *sigdata;
5116 int pkblob_len, sigblob_len, sigdata_len;
5117 int p;
5118
5119 /*
5120 * We have loaded the private key and the server
5121 * has announced that it's willing to accept it.
5122 * Hallelujah. Generate a signature and send it.
5123 */
5124 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
5125 ssh2_pkt_addstring(ssh, s->username);
5126 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
5127 ssh2_pkt_addstring(ssh, "publickey"); /* method */
5128 ssh2_pkt_addbool(ssh, TRUE);
5129 ssh2_pkt_addstring(ssh, key->alg->name);
5130 pkblob = key->alg->public_blob(key->data, &pkblob_len);
5131 ssh2_pkt_addstring_start(ssh);
5132 ssh2_pkt_addstring_data(ssh, (char *)pkblob, pkblob_len);
5133
5134 /*
5135 * The data to be signed is:
5136 *
5137 * string session-id
5138 *
5139 * followed by everything so far placed in the
5140 * outgoing packet.
5141 */
5142 sigdata_len = ssh->pktout.length - 5 + 4 + 20;
5143 if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
5144 sigdata_len -= 4;
5145 sigdata = snewn(sigdata_len, unsigned char);
5146 p = 0;
5147 if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
5148 PUT_32BIT(sigdata+p, 20);
5149 p += 4;
5150 }
5151 memcpy(sigdata+p, ssh->v2_session_id, 20); p += 20;
5152 memcpy(sigdata+p, ssh->pktout.data + 5,
5153 ssh->pktout.length - 5);
5154 p += ssh->pktout.length - 5;
5155 assert(p == sigdata_len);
5156 sigblob = key->alg->sign(key->data, (char *)sigdata,
5157 sigdata_len, &sigblob_len);
5158 ssh2_add_sigblob(ssh, pkblob, pkblob_len,
5159 sigblob, sigblob_len);
5160 sfree(pkblob);
5161 sfree(sigblob);
5162 sfree(sigdata);
5163
5164 ssh2_pkt_send(ssh);
5165 s->type = AUTH_TYPE_PUBLICKEY;
5166 }
5167 } else if (s->method == AUTH_PASSWORD) {
5168 /*
5169 * We send the password packet lumped tightly together with
5170 * an SSH_MSG_IGNORE packet. The IGNORE packet contains a
5171 * string long enough to make the total length of the two
5172 * packets constant. This should ensure that a passive
5173 * listener doing traffic analyis can't work out the length
5174 * of the password.
5175 *
5176 * For this to work, we need an assumption about the
5177 * maximum length of the password packet. I think 256 is
5178 * pretty conservative. Anyone using a password longer than
5179 * that probably doesn't have much to worry about from
5180 * people who find out how long their password is!
5181 */
5182 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
5183 ssh2_pkt_addstring(ssh, s->username);
5184 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
5185 ssh2_pkt_addstring(ssh, "password");
5186 ssh2_pkt_addbool(ssh, FALSE);
5187 ssh2_pkt_addstring(ssh, s->password);
5188 memset(s->password, 0, sizeof(s->password));
5189 ssh2_pkt_defer(ssh);
5190 /*
5191 * We'll include a string that's an exact multiple of the
5192 * cipher block size. If the cipher is NULL for some
5193 * reason, we don't do this trick at all because we gain
5194 * nothing by it.
5195 */
5196 if (ssh->cscipher) {
5197 int stringlen, i;
5198
5199 stringlen = (256 - ssh->deferred_len);
5200 stringlen += ssh->cscipher->blksize - 1;
5201 stringlen -= (stringlen % ssh->cscipher->blksize);
5202 if (ssh->cscomp) {
5203 /*
5204 * Temporarily disable actual compression,
5205 * so we can guarantee to get this string
5206 * exactly the length we want it. The
5207 * compression-disabling routine should
5208 * return an integer indicating how many
5209 * bytes we should adjust our string length
5210 * by.
5211 */
5212 stringlen -=
5213 ssh->cscomp->disable_compression(ssh->cs_comp_ctx);
5214 }
5215 ssh2_pkt_init(ssh, SSH2_MSG_IGNORE);
5216 ssh2_pkt_addstring_start(ssh);
5217 for (i = 0; i < stringlen; i++) {
5218 char c = (char) random_byte();
5219 ssh2_pkt_addstring_data(ssh, &c, 1);
5220 }
5221 ssh2_pkt_defer(ssh);
5222 }
5223 ssh_pkt_defersend(ssh);
5224 logevent("Sent password");
5225 s->type = AUTH_TYPE_PASSWORD;
5226 } else if (s->method == AUTH_KEYBOARD_INTERACTIVE) {
5227 if (s->curr_prompt == 0) {
5228 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_INFO_RESPONSE);
5229 ssh2_pkt_adduint32(ssh, s->num_prompts);
5230 }
5231 if (s->need_pw) { /* only add pw if we just got one! */
5232 ssh2_pkt_addstring(ssh, s->password);
5233 memset(s->password, 0, sizeof(s->password));
5234 s->curr_prompt++;
5235 }
5236 if (s->curr_prompt >= s->num_prompts) {
5237 ssh2_pkt_send(ssh);
5238 } else {
5239 /*
5240 * If there are prompts remaining, we set
5241 * `gotit' so that we won't attempt to get
5242 * another packet. Then we go back round the
5243 * loop and will end up retrieving another
5244 * prompt out of the existing packet. Funky or
5245 * what?
5246 */
5247 s->gotit = TRUE;
5248 }
5249 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
5250 } else {
5251 c_write_str(ssh, "No supported authentication methods"
5252 " left to try!\r\n");
5253 logevent("No supported authentications offered."
5254 " Disconnecting");
5255 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5256 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5257 ssh2_pkt_addstring(ssh, "No supported authentication"
5258 " methods available");
5259 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5260 ssh2_pkt_send(ssh);
5261 ssh_closing((Plug)ssh, NULL, 0, 0);
5262 crStopV;
5263 }
5264 }
5265 } while (!s->we_are_in);
5266
5267 /*
5268 * Now we're authenticated for the connection protocol. The
5269 * connection protocol will automatically have started at this
5270 * point; there's no need to send SERVICE_REQUEST.
5271 */
5272
5273 /*
5274 * So now create a channel with a session in it.
5275 */
5276 ssh->channels = newtree234(ssh_channelcmp);
5277 ssh->mainchan = snew(struct ssh_channel);
5278 ssh->mainchan->ssh = ssh;
5279 ssh->mainchan->localid = alloc_channel_id(ssh);
5280 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN);
5281 ssh2_pkt_addstring(ssh, "session");
5282 ssh2_pkt_adduint32(ssh, ssh->mainchan->localid);
5283 ssh->mainchan->v.v2.locwindow = OUR_V2_WINSIZE;
5284 ssh2_pkt_adduint32(ssh, ssh->mainchan->v.v2.locwindow);/* our window size */
5285 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
5286 ssh2_pkt_send(ssh);
5287 crWaitUntilV(ispkt);
5288 if (ssh->pktin.type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
5289 bombout(("Server refused to open a session"));
5290 crStopV;
5291 /* FIXME: error data comes back in FAILURE packet */
5292 }
5293 if (ssh2_pkt_getuint32(ssh) != ssh->mainchan->localid) {
5294 bombout(("Server's channel confirmation cited wrong channel"));
5295 crStopV;
5296 }
5297 ssh->mainchan->remoteid = ssh2_pkt_getuint32(ssh);
5298 ssh->mainchan->type = CHAN_MAINSESSION;
5299 ssh->mainchan->closes = 0;
5300 ssh->mainchan->v.v2.remwindow = ssh2_pkt_getuint32(ssh);
5301 ssh->mainchan->v.v2.remmaxpkt = ssh2_pkt_getuint32(ssh);
5302 bufchain_init(&ssh->mainchan->v.v2.outbuffer);
5303 add234(ssh->channels, ssh->mainchan);
5304 logevent("Opened channel for session");
5305
5306 /*
5307 * Potentially enable X11 forwarding.
5308 */
5309 if (ssh->cfg.x11_forward) {
5310 char proto[20], data[64];
5311 logevent("Requesting X11 forwarding");
5312 ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
5313 data, sizeof(data), ssh->cfg.x11_auth);
5314 x11_get_real_auth(ssh->x11auth, ssh->cfg.x11_display);
5315 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5316 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
5317 ssh2_pkt_addstring(ssh, "x11-req");
5318 ssh2_pkt_addbool(ssh, 1); /* want reply */
5319 ssh2_pkt_addbool(ssh, 0); /* many connections */
5320 ssh2_pkt_addstring(ssh, proto);
5321 ssh2_pkt_addstring(ssh, data);
5322 ssh2_pkt_adduint32(ssh, x11_get_screen_number(ssh->cfg.x11_display));
5323 ssh2_pkt_send(ssh);
5324
5325 do {
5326 crWaitUntilV(ispkt);
5327 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5328 unsigned i = ssh2_pkt_getuint32(ssh);
5329 struct ssh_channel *c;
5330 c = find234(ssh->channels, &i, ssh_channelfind);
5331 if (!c)
5332 continue; /* nonexistent channel */
5333 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5334 }
5335 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5336
5337 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5338 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5339 bombout(("Unexpected response to X11 forwarding request:"
5340 " packet type %d", ssh->pktin.type));
5341 crStopV;
5342 }
5343 logevent("X11 forwarding refused");
5344 } else {
5345 logevent("X11 forwarding enabled");
5346 ssh->X11_fwd_enabled = TRUE;
5347 }
5348 }
5349
5350 /*
5351 * Enable port forwardings.
5352 */
5353 {
5354 char type;
5355 int n;
5356 int sport,dport,sserv,dserv;
5357 char sports[256], dports[256], saddr[256], host[256];
5358
5359 ssh->rportfwds = newtree234(ssh_rportcmp_ssh2);
5360 /* Add port forwardings. */
5361 ssh->portfwd_strptr = ssh->cfg.portfwd;
5362 while (*ssh->portfwd_strptr) {
5363 type = *ssh->portfwd_strptr++;
5364 saddr[0] = '\0';
5365 n = 0;
5366 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != '\t') {
5367 if (*ssh->portfwd_strptr == ':') {
5368 /*
5369 * We've seen a colon in the middle of the
5370 * source port number. This means that
5371 * everything we've seen until now is the
5372 * source _address_, so we'll move it into
5373 * saddr and start sports from the beginning
5374 * again.
5375 */
5376 ssh->portfwd_strptr++;
5377 sports[n] = '\0';
5378 strcpy(saddr, sports);
5379 n = 0;
5380 }
5381 if (n < 255) sports[n++] = *ssh->portfwd_strptr++;
5382 }
5383 sports[n] = 0;
5384 if (type != 'D') {
5385 if (*ssh->portfwd_strptr == '\t')
5386 ssh->portfwd_strptr++;
5387 n = 0;
5388 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':') {
5389 if (n < 255) host[n++] = *ssh->portfwd_strptr++;
5390 }
5391 host[n] = 0;
5392 if (*ssh->portfwd_strptr == ':')
5393 ssh->portfwd_strptr++;
5394 n = 0;
5395 while (*ssh->portfwd_strptr) {
5396 if (n < 255) dports[n++] = *ssh->portfwd_strptr++;
5397 }
5398 dports[n] = 0;
5399 ssh->portfwd_strptr++;
5400 dport = atoi(dports);
5401 dserv = 0;
5402 if (dport == 0) {
5403 dserv = 1;
5404 dport = net_service_lookup(dports);
5405 if (!dport) {
5406 logeventf(ssh, "Service lookup failed for destination"
5407 " port \"%s\"", dports);
5408 }
5409 }
5410 } else {
5411 while (*ssh->portfwd_strptr) ssh->portfwd_strptr++;
5412 dport = dserv = -1;
5413 }
5414 sport = atoi(sports);
5415 sserv = 0;
5416 if (sport == 0) {
5417 sserv = 1;
5418 sport = net_service_lookup(sports);
5419 if (!sport) {
5420 logeventf(ssh, "Service lookup failed for source"
5421 " port \"%s\"", sports);
5422 }
5423 }
5424 if (sport && dport) {
5425 if (type == 'L') {
5426 pfd_addforward(host, dport, *saddr ? saddr : NULL,
5427 sport, ssh, &ssh->cfg);
5428 logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
5429 " forwarding to %s:%.*s%.*s%d%.*s",
5430 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
5431 (int)(*saddr?1:0), ":",
5432 (int)(sserv ? strlen(sports) : 0), sports,
5433 sserv, "(", sport, sserv, ")",
5434 host,
5435 (int)(dserv ? strlen(dports) : 0), dports,
5436 dserv, "(", dport, dserv, ")");
5437 } else if (type == 'D') {
5438 pfd_addforward(NULL, -1, *saddr ? saddr : NULL,
5439 sport, ssh, &ssh->cfg);
5440 logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
5441 " doing SOCKS dynamic forwarding",
5442 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
5443 (int)(*saddr?1:0), ":",
5444 (int)(sserv ? strlen(sports) : 0), sports,
5445 sserv, "(", sport, sserv, ")");
5446 } else {
5447 struct ssh_rportfwd *pf;
5448 pf = snew(struct ssh_rportfwd);
5449 strcpy(pf->dhost, host);
5450 pf->dport = dport;
5451 pf->sport = sport;
5452 if (add234(ssh->rportfwds, pf) != pf) {
5453 logeventf(ssh, "Duplicate remote port forwarding"
5454 " to %s:%d", host, dport);
5455 sfree(pf);
5456 } else {
5457 logeventf(ssh, "Requesting remote port "
5458 "%.*s%.*s%.*s%.*s%d%.*s"
5459 " forward to %s:%.*s%.*s%d%.*s",
5460 (int)(*saddr?strlen(saddr):0),
5461 *saddr?saddr:NULL,
5462 (int)(*saddr?1:0), ":",
5463 (int)(sserv ? strlen(sports) : 0), sports,
5464 sserv, "(", sport, sserv, ")",
5465 host,
5466 (int)(dserv ? strlen(dports) : 0), dports,
5467 dserv, "(", dport, dserv, ")");
5468 ssh2_pkt_init(ssh, SSH2_MSG_GLOBAL_REQUEST);
5469 ssh2_pkt_addstring(ssh, "tcpip-forward");
5470 ssh2_pkt_addbool(ssh, 1);/* want reply */
5471 if (*saddr)
5472 ssh2_pkt_addstring(ssh, saddr);
5473 if (ssh->cfg.rport_acceptall)
5474 ssh2_pkt_addstring(ssh, "0.0.0.0");
5475 else
5476 ssh2_pkt_addstring(ssh, "127.0.0.1");
5477 ssh2_pkt_adduint32(ssh, sport);
5478 ssh2_pkt_send(ssh);
5479
5480 do {
5481 crWaitUntilV(ispkt);
5482 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5483 unsigned i = ssh2_pkt_getuint32(ssh);
5484 struct ssh_channel *c;
5485 c = find234(ssh->channels, &i, ssh_channelfind);
5486 if (!c)
5487 continue;/* nonexistent channel */
5488 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5489 }
5490 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5491
5492 if (ssh->pktin.type != SSH2_MSG_REQUEST_SUCCESS) {
5493 if (ssh->pktin.type != SSH2_MSG_REQUEST_FAILURE) {
5494 bombout(("Unexpected response to port "
5495 "forwarding request: packet type %d",
5496 ssh->pktin.type));
5497 crStopV;
5498 }
5499 logevent("Server refused this port forwarding");
5500 } else {
5501 logevent("Remote port forwarding enabled");
5502 }
5503 }
5504 }
5505 }
5506 }
5507 }
5508
5509 /*
5510 * Potentially enable agent forwarding.
5511 */
5512 if (ssh->cfg.agentfwd && agent_exists()) {
5513 logevent("Requesting OpenSSH-style agent forwarding");
5514 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5515 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
5516 ssh2_pkt_addstring(ssh, "auth-agent-req@openssh.com");
5517 ssh2_pkt_addbool(ssh, 1); /* want reply */
5518 ssh2_pkt_send(ssh);
5519
5520 do {
5521 crWaitUntilV(ispkt);
5522 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5523 unsigned i = ssh2_pkt_getuint32(ssh);
5524 struct ssh_channel *c;
5525 c = find234(ssh->channels, &i, ssh_channelfind);
5526 if (!c)
5527 continue; /* nonexistent channel */
5528 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5529 }
5530 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5531
5532 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5533 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5534 bombout(("Unexpected response to agent forwarding request:"
5535 " packet type %d", ssh->pktin.type));
5536 crStopV;
5537 }
5538 logevent("Agent forwarding refused");
5539 } else {
5540 logevent("Agent forwarding enabled");
5541 ssh->agentfwd_enabled = TRUE;
5542 }
5543 }
5544
5545 /*
5546 * Now allocate a pty for the session.
5547 */
5548 if (!ssh->cfg.nopty) {
5549 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5550 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid); /* recipient channel */
5551 ssh2_pkt_addstring(ssh, "pty-req");
5552 ssh2_pkt_addbool(ssh, 1); /* want reply */
5553 ssh2_pkt_addstring(ssh, ssh->cfg.termtype);
5554 ssh2_pkt_adduint32(ssh, ssh->term_width);
5555 ssh2_pkt_adduint32(ssh, ssh->term_height);
5556 ssh2_pkt_adduint32(ssh, 0); /* pixel width */
5557 ssh2_pkt_adduint32(ssh, 0); /* pixel height */
5558 ssh2_pkt_addstring_start(ssh);
5559 ssh2_pkt_addstring_data(ssh, "\0", 1); /* TTY_OP_END, no special options */
5560 ssh2_pkt_send(ssh);
5561 ssh->state = SSH_STATE_INTERMED;
5562
5563 do {
5564 crWaitUntilV(ispkt);
5565 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5566 unsigned i = ssh2_pkt_getuint32(ssh);
5567 struct ssh_channel *c;
5568 c = find234(ssh->channels, &i, ssh_channelfind);
5569 if (!c)
5570 continue; /* nonexistent channel */
5571 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5572 }
5573 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5574
5575 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5576 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5577 bombout(("Unexpected response to pty request:"
5578 " packet type %d", ssh->pktin.type));
5579 crStopV;
5580 }
5581 c_write_str(ssh, "Server refused to allocate pty\r\n");
5582 ssh->editing = ssh->echoing = 1;
5583 } else {
5584 logevent("Allocated pty");
5585 }
5586 } else {
5587 ssh->editing = ssh->echoing = 1;
5588 }
5589
5590 /*
5591 * Start a shell or a remote command. We may have to attempt
5592 * this twice if the config data has provided a second choice
5593 * of command.
5594 */
5595 while (1) {
5596 int subsys;
5597 char *cmd;
5598
5599 if (ssh->fallback_cmd) {
5600 subsys = ssh->cfg.ssh_subsys2;
5601 cmd = ssh->cfg.remote_cmd_ptr2;
5602 } else {
5603 subsys = ssh->cfg.ssh_subsys;
5604 cmd = ssh->cfg.remote_cmd_ptr;
5605 }
5606
5607 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5608 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid); /* recipient channel */
5609 if (subsys) {
5610 ssh2_pkt_addstring(ssh, "subsystem");
5611 ssh2_pkt_addbool(ssh, 1); /* want reply */
5612 ssh2_pkt_addstring(ssh, cmd);
5613 } else if (*cmd) {
5614 ssh2_pkt_addstring(ssh, "exec");
5615 ssh2_pkt_addbool(ssh, 1); /* want reply */
5616 ssh2_pkt_addstring(ssh, cmd);
5617 } else {
5618 ssh2_pkt_addstring(ssh, "shell");
5619 ssh2_pkt_addbool(ssh, 1); /* want reply */
5620 }
5621 ssh2_pkt_send(ssh);
5622 do {
5623 crWaitUntilV(ispkt);
5624 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5625 unsigned i = ssh2_pkt_getuint32(ssh);
5626 struct ssh_channel *c;
5627 c = find234(ssh->channels, &i, ssh_channelfind);
5628 if (!c)
5629 continue; /* nonexistent channel */
5630 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5631 }
5632 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5633 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5634 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5635 bombout(("Unexpected response to shell/command request:"
5636 " packet type %d", ssh->pktin.type));
5637 crStopV;
5638 }
5639 /*
5640 * We failed to start the command. If this is the
5641 * fallback command, we really are finished; if it's
5642 * not, and if the fallback command exists, try falling
5643 * back to it before complaining.
5644 */
5645 if (!ssh->fallback_cmd && ssh->cfg.remote_cmd_ptr2 != NULL) {
5646 logevent("Primary command failed; attempting fallback");
5647 ssh->fallback_cmd = TRUE;
5648 continue;
5649 }
5650 bombout(("Server refused to start a shell/command"));
5651 crStopV;
5652 } else {
5653 logevent("Started a shell/command");
5654 }
5655 break;
5656 }
5657
5658 ssh->state = SSH_STATE_SESSION;
5659 if (ssh->size_needed)
5660 ssh_size(ssh, ssh->term_width, ssh->term_height);
5661 if (ssh->eof_needed)
5662 ssh_special(ssh, TS_EOF);
5663
5664 /*
5665 * Transfer data!
5666 */
5667 if (ssh->ldisc)
5668 ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */
5669 ssh->send_ok = 1;
5670 while (1) {
5671 crReturnV;
5672 s->try_send = FALSE;
5673 if (ispkt) {
5674 if (ssh->pktin.type == SSH2_MSG_CHANNEL_DATA ||
5675 ssh->pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA) {
5676 char *data;
5677 int length;
5678 unsigned i = ssh2_pkt_getuint32(ssh);
5679 struct ssh_channel *c;
5680 c = find234(ssh->channels, &i, ssh_channelfind);
5681 if (!c)
5682 continue; /* nonexistent channel */
5683 if (ssh->pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
5684 ssh2_pkt_getuint32(ssh) != SSH2_EXTENDED_DATA_STDERR)
5685 continue; /* extended but not stderr */
5686 ssh2_pkt_getstring(ssh, &data, &length);
5687 if (data) {
5688 int bufsize = 0;
5689 c->v.v2.locwindow -= length;
5690 switch (c->type) {
5691 case CHAN_MAINSESSION:
5692 bufsize =
5693 from_backend(ssh->frontend, ssh->pktin.type ==
5694 SSH2_MSG_CHANNEL_EXTENDED_DATA,
5695 data, length);
5696 break;
5697 case CHAN_X11:
5698 bufsize = x11_send(c->u.x11.s, data, length);
5699 break;
5700 case CHAN_SOCKDATA:
5701 bufsize = pfd_send(c->u.pfd.s, data, length);
5702 break;
5703 case CHAN_AGENT:
5704 while (length > 0) {
5705 if (c->u.a.lensofar < 4) {
5706 int l = min(4 - c->u.a.lensofar, length);
5707 memcpy(c->u.a.msglen + c->u.a.lensofar,
5708 data, l);
5709 data += l;
5710 length -= l;
5711 c->u.a.lensofar += l;
5712 }
5713 if (c->u.a.lensofar == 4) {
5714 c->u.a.totallen =
5715 4 + GET_32BIT(c->u.a.msglen);
5716 c->u.a.message = snewn(c->u.a.totallen,
5717 unsigned char);
5718 memcpy(c->u.a.message, c->u.a.msglen, 4);
5719 }
5720 if (c->u.a.lensofar >= 4 && length > 0) {
5721 int l =
5722 min(c->u.a.totallen - c->u.a.lensofar,
5723 length);
5724 memcpy(c->u.a.message + c->u.a.lensofar,
5725 data, l);
5726 data += l;
5727 length -= l;
5728 c->u.a.lensofar += l;
5729 }
5730 if (c->u.a.lensofar == c->u.a.totallen) {
5731 void *reply;
5732 int replylen;
5733 if (agent_query(c->u.a.message,
5734 c->u.a.totallen,
5735 &reply, &replylen,
5736 ssh_agentf_callback, c))
5737 ssh_agentf_callback(c, reply, replylen);
5738 sfree(c->u.a.message);
5739 c->u.a.lensofar = 0;
5740 }
5741 }
5742 bufsize = 0;
5743 break;
5744 }
5745 /*
5746 * If we are not buffering too much data,
5747 * enlarge the window again at the remote side.
5748 */
5749 if (bufsize < OUR_V2_WINSIZE)
5750 ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
5751 }
5752 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_EOF) {
5753 unsigned i = ssh2_pkt_getuint32(ssh);
5754 struct ssh_channel *c;
5755
5756 c = find234(ssh->channels, &i, ssh_channelfind);
5757 if (!c)
5758 continue; /* nonexistent channel */
5759
5760 if (c->type == CHAN_X11) {
5761 /*
5762 * Remote EOF on an X11 channel means we should
5763 * wrap up and close the channel ourselves.
5764 */
5765 x11_close(c->u.x11.s);
5766 sshfwd_close(c);
5767 } else if (c->type == CHAN_AGENT) {
5768 sshfwd_close(c);
5769 } else if (c->type == CHAN_SOCKDATA) {
5770 pfd_close(c->u.pfd.s);
5771 sshfwd_close(c);
5772 }
5773 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_CLOSE) {
5774 unsigned i = ssh2_pkt_getuint32(ssh);
5775 struct ssh_channel *c;
5776
5777 c = find234(ssh->channels, &i, ssh_channelfind);
5778 if (!c || ((int)c->remoteid) == -1) {
5779 bombout(("Received CHANNEL_CLOSE for %s channel %d\n",
5780 c ? "half-open" : "nonexistent", i));
5781 crStopV;
5782 }
5783 /* Do pre-close processing on the channel. */
5784 switch (c->type) {
5785 case CHAN_MAINSESSION:
5786 break; /* nothing to see here, move along */
5787 case CHAN_X11:
5788 if (c->u.x11.s != NULL)
5789 x11_close(c->u.x11.s);
5790 sshfwd_close(c);
5791 break;
5792 case CHAN_AGENT:
5793 sshfwd_close(c);
5794 break;
5795 case CHAN_SOCKDATA:
5796 if (c->u.pfd.s != NULL)
5797 pfd_close(c->u.pfd.s);
5798 sshfwd_close(c);
5799 break;
5800 }
5801 if (c->closes == 0) {
5802 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
5803 ssh2_pkt_adduint32(ssh, c->remoteid);
5804 ssh2_pkt_send(ssh);
5805 }
5806 del234(ssh->channels, c);
5807 bufchain_clear(&c->v.v2.outbuffer);
5808 sfree(c);
5809
5810 /*
5811 * See if that was the last channel left open.
5812 */
5813 if (count234(ssh->channels) == 0) {
5814 logevent("All channels closed. Disconnecting");
5815 #if 0
5816 /*
5817 * We used to send SSH_MSG_DISCONNECT here,
5818 * because I'd believed that _every_ conforming
5819 * SSH2 connection had to end with a disconnect
5820 * being sent by at least one side; apparently
5821 * I was wrong and it's perfectly OK to
5822 * unceremoniously slam the connection shut
5823 * when you're done, and indeed OpenSSH feels
5824 * this is more polite than sending a
5825 * DISCONNECT. So now we don't.
5826 */
5827 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5828 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5829 ssh2_pkt_addstring(ssh, "All open channels closed");
5830 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5831 ssh2_pkt_send(ssh);
5832 #endif
5833 ssh_closing((Plug)ssh, NULL, 0, 0);
5834 crStopV;
5835 }
5836 continue; /* remote sends close; ignore (FIXME) */
5837 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5838 unsigned i = ssh2_pkt_getuint32(ssh);
5839 struct ssh_channel *c;
5840 c = find234(ssh->channels, &i, ssh_channelfind);
5841 if (!c || c->closes)
5842 continue; /* nonexistent or closing channel */
5843 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5844 s->try_send = TRUE;
5845 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
5846 unsigned i = ssh2_pkt_getuint32(ssh);
5847 struct ssh_channel *c;
5848 c = find234(ssh->channels, &i, ssh_channelfind);
5849 if (!c)
5850 continue; /* nonexistent channel */
5851 if (c->type != CHAN_SOCKDATA_DORMANT)
5852 continue; /* dunno why they're confirming this */
5853 c->remoteid = ssh2_pkt_getuint32(ssh);
5854 c->type = CHAN_SOCKDATA;
5855 c->v.v2.remwindow = ssh2_pkt_getuint32(ssh);
5856 c->v.v2.remmaxpkt = ssh2_pkt_getuint32(ssh);
5857 if (c->u.pfd.s)
5858 pfd_confirm(c->u.pfd.s);
5859 if (c->closes) {
5860 /*
5861 * We have a pending close on this channel,
5862 * which we decided on before the server acked
5863 * the channel open. So now we know the
5864 * remoteid, we can close it again.
5865 */
5866 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
5867 ssh2_pkt_adduint32(ssh, c->remoteid);
5868 ssh2_pkt_send(ssh);
5869 }
5870 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN_FAILURE) {
5871 unsigned i = ssh2_pkt_getuint32(ssh);
5872 struct ssh_channel *c;
5873 c = find234(ssh->channels, &i, ssh_channelfind);
5874 if (!c)
5875 continue; /* nonexistent channel */
5876 if (c->type != CHAN_SOCKDATA_DORMANT)
5877 continue; /* dunno why they're failing this */
5878
5879 logevent("Forwarded connection refused by server");
5880
5881 pfd_close(c->u.pfd.s);
5882
5883 del234(ssh->channels, c);
5884 sfree(c);
5885 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_REQUEST) {
5886 unsigned localid;
5887 char *type;
5888 int typelen, want_reply;
5889 struct ssh_channel *c;
5890
5891 localid = ssh2_pkt_getuint32(ssh);
5892 ssh2_pkt_getstring(ssh, &type, &typelen);
5893 want_reply = ssh2_pkt_getbool(ssh);
5894
5895 /*
5896 * First, check that the channel exists. Otherwise,
5897 * we can instantly disconnect with a rude message.
5898 */
5899 c = find234(ssh->channels, &localid, ssh_channelfind);
5900 if (!c) {
5901 char buf[80];
5902 sprintf(buf, "Received channel request for nonexistent"
5903 " channel %d", localid);
5904 logevent(buf);
5905 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5906 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5907 ssh2_pkt_addstring(ssh, buf);
5908 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5909 ssh2_pkt_send(ssh);
5910 connection_fatal(ssh->frontend, "%s", buf);
5911 ssh_closing((Plug)ssh, NULL, 0, 0);
5912 crStopV;
5913 }
5914
5915 /*
5916 * Having got the channel number, we now look at
5917 * the request type string to see if it's something
5918 * we recognise.
5919 */
5920 if (typelen == 11 && !memcmp(type, "exit-status", 11) &&
5921 c == ssh->mainchan) {
5922 /* We recognise "exit-status" on the primary channel. */
5923 char buf[100];
5924 ssh->exitcode = ssh2_pkt_getuint32(ssh);
5925 sprintf(buf, "Server sent command exit status %d",
5926 ssh->exitcode);
5927 logevent(buf);
5928 if (want_reply) {
5929 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_SUCCESS);
5930 ssh2_pkt_adduint32(ssh, c->remoteid);
5931 ssh2_pkt_send(ssh);
5932 }
5933 } else {
5934 /*
5935 * This is a channel request we don't know
5936 * about, so we now either ignore the request
5937 * or respond with CHANNEL_FAILURE, depending
5938 * on want_reply.
5939 */
5940 if (want_reply) {
5941 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_FAILURE);
5942 ssh2_pkt_adduint32(ssh, c->remoteid);
5943 ssh2_pkt_send(ssh);
5944 }
5945 }
5946 } else if (ssh->pktin.type == SSH2_MSG_GLOBAL_REQUEST) {
5947 char *type;
5948 int typelen, want_reply;
5949
5950 ssh2_pkt_getstring(ssh, &type, &typelen);
5951 want_reply = ssh2_pkt_getbool(ssh);
5952
5953 /*
5954 * We currently don't support any global requests
5955 * at all, so we either ignore the request or
5956 * respond with REQUEST_FAILURE, depending on
5957 * want_reply.
5958 */
5959 if (want_reply) {
5960 ssh2_pkt_init(ssh, SSH2_MSG_REQUEST_FAILURE);
5961 ssh2_pkt_send(ssh);
5962 }
5963 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN) {
5964 char *type;
5965 int typelen;
5966 char *peeraddr;
5967 int peeraddrlen;
5968 int peerport;
5969 char *error = NULL;
5970 struct ssh_channel *c;
5971 unsigned remid, winsize, pktsize;
5972 ssh2_pkt_getstring(ssh, &type, &typelen);
5973 c = snew(struct ssh_channel);
5974 c->ssh = ssh;
5975
5976 remid = ssh2_pkt_getuint32(ssh);
5977 winsize = ssh2_pkt_getuint32(ssh);
5978 pktsize = ssh2_pkt_getuint32(ssh);
5979
5980 if (typelen == 3 && !memcmp(type, "x11", 3)) {
5981 char *addrstr;
5982
5983 ssh2_pkt_getstring(ssh, &peeraddr, &peeraddrlen);
5984 addrstr = snewn(peeraddrlen+1, char);
5985 memcpy(addrstr, peeraddr, peeraddrlen);
5986 peeraddr[peeraddrlen] = '\0';
5987 peerport = ssh2_pkt_getuint32(ssh);
5988
5989 if (!ssh->X11_fwd_enabled)
5990 error = "X11 forwarding is not enabled";
5991 else if (x11_init(&c->u.x11.s, ssh->cfg.x11_display, c,
5992 ssh->x11auth, addrstr, peerport,
5993 &ssh->cfg) != NULL) {
5994 error = "Unable to open an X11 connection";
5995 } else {
5996 c->type = CHAN_X11;
5997 }
5998
5999 sfree(addrstr);
6000 } else if (typelen == 15 &&
6001 !memcmp(type, "forwarded-tcpip", 15)) {
6002 struct ssh_rportfwd pf, *realpf;
6003 char *dummy;
6004 int dummylen;
6005 ssh2_pkt_getstring(ssh, &dummy, &dummylen);/* skip address */
6006 pf.sport = ssh2_pkt_getuint32(ssh);
6007 ssh2_pkt_getstring(ssh, &peeraddr, &peeraddrlen);
6008 peerport = ssh2_pkt_getuint32(ssh);
6009 realpf = find234(ssh->rportfwds, &pf, NULL);
6010 if (realpf == NULL) {
6011 error = "Remote port is not recognised";
6012 } else {
6013 const char *e = pfd_newconnect(&c->u.pfd.s,
6014 realpf->dhost,
6015 realpf->dport, c,
6016 &ssh->cfg);
6017 logeventf(ssh, "Received remote port open request"
6018 " for %s:%d", realpf->dhost, realpf->dport);
6019 if (e != NULL) {
6020 logeventf(ssh, "Port open failed: %s", e);
6021 error = "Port open failed";
6022 } else {
6023 logevent("Forwarded port opened successfully");
6024 c->type = CHAN_SOCKDATA;
6025 }
6026 }
6027 } else if (typelen == 22 &&
6028 !memcmp(type, "auth-agent@openssh.com", 3)) {
6029 if (!ssh->agentfwd_enabled)
6030 error = "Agent forwarding is not enabled";
6031 else {
6032 c->type = CHAN_AGENT; /* identify channel type */
6033 c->u.a.lensofar = 0;
6034 }
6035 } else {
6036 error = "Unsupported channel type requested";
6037 }
6038
6039 c->remoteid = remid;
6040 if (error) {
6041 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN_FAILURE);
6042 ssh2_pkt_adduint32(ssh, c->remoteid);
6043 ssh2_pkt_adduint32(ssh, SSH2_OPEN_CONNECT_FAILED);
6044 ssh2_pkt_addstring(ssh, error);
6045 ssh2_pkt_addstring(ssh, "en"); /* language tag */
6046 ssh2_pkt_send(ssh);
6047 sfree(c);
6048 } else {
6049 c->localid = alloc_channel_id(ssh);
6050 c->closes = 0;
6051 c->v.v2.locwindow = OUR_V2_WINSIZE;
6052 c->v.v2.remwindow = winsize;
6053 c->v.v2.remmaxpkt = pktsize;
6054 bufchain_init(&c->v.v2.outbuffer);
6055 add234(ssh->channels, c);
6056 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
6057 ssh2_pkt_adduint32(ssh, c->remoteid);
6058 ssh2_pkt_adduint32(ssh, c->localid);
6059 ssh2_pkt_adduint32(ssh, c->v.v2.locwindow);
6060 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
6061 ssh2_pkt_send(ssh);
6062 }
6063 } else {
6064 bombout(("Strange packet received: type %d", ssh->pktin.type));
6065 crStopV;
6066 }
6067 } else {
6068 /*
6069 * We have spare data. Add it to the channel buffer.
6070 */
6071 ssh2_add_channel_data(ssh->mainchan, (char *)in, inlen);
6072 s->try_send = TRUE;
6073 }
6074 if (s->try_send) {
6075 int i;
6076 struct ssh_channel *c;
6077 /*
6078 * Try to send data on all channels if we can.
6079 */
6080 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
6081 int bufsize;
6082 if (c->closes)
6083 continue; /* don't send on closing channels */
6084 bufsize = ssh2_try_send(c);
6085 if (bufsize == 0) {
6086 switch (c->type) {
6087 case CHAN_MAINSESSION:
6088 /* stdin need not receive an unthrottle
6089 * notification since it will be polled */
6090 break;
6091 case CHAN_X11:
6092 x11_unthrottle(c->u.x11.s);
6093 break;
6094 case CHAN_AGENT:
6095 /* agent sockets are request/response and need no
6096 * buffer management */
6097 break;
6098 case CHAN_SOCKDATA:
6099 pfd_unthrottle(c->u.pfd.s);
6100 break;
6101 }
6102 }
6103 }
6104 }
6105 }
6106
6107 crFinishV;
6108 }
6109
6110 /*
6111 * Handle the top-level SSH2 protocol.
6112 */
6113 static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
6114 {
6115 if (do_ssh2_transport(ssh, in, inlen, ispkt) == 0)
6116 return;
6117 do_ssh2_authconn(ssh, in, inlen, ispkt);
6118 }
6119
6120 /*
6121 * Called to set up the connection.
6122 *
6123 * Returns an error message, or NULL on success.
6124 */
6125 static const char *ssh_init(void *frontend_handle, void **backend_handle,
6126 Config *cfg,
6127 char *host, int port, char **realhost, int nodelay)
6128 {
6129 const char *p;
6130 Ssh ssh;
6131
6132 ssh = snew(struct ssh_tag);
6133 ssh->cfg = *cfg; /* STRUCTURE COPY */
6134 ssh->version = 0; /* when not ready yet */
6135 ssh->s = NULL;
6136 ssh->cipher = NULL;
6137 ssh->v1_cipher_ctx = NULL;
6138 ssh->crcda_ctx = NULL;
6139 ssh->cscipher = NULL;
6140 ssh->cs_cipher_ctx = NULL;
6141 ssh->sccipher = NULL;
6142 ssh->sc_cipher_ctx = NULL;
6143 ssh->csmac = NULL;
6144 ssh->cs_mac_ctx = NULL;
6145 ssh->scmac = NULL;
6146 ssh->sc_mac_ctx = NULL;
6147 ssh->cscomp = NULL;
6148 ssh->cs_comp_ctx = NULL;
6149 ssh->sccomp = NULL;
6150 ssh->sc_comp_ctx = NULL;
6151 ssh->kex = NULL;
6152 ssh->kex_ctx = NULL;
6153 ssh->hostkey = NULL;
6154 ssh->exitcode = -1;
6155 ssh->state = SSH_STATE_PREPACKET;
6156 ssh->size_needed = FALSE;
6157 ssh->eof_needed = FALSE;
6158 ssh->ldisc = NULL;
6159 ssh->logctx = NULL;
6160 {
6161 static const struct Packet empty = { 0, 0, NULL, NULL, 0 };
6162 ssh->pktin = ssh->pktout = empty;
6163 }
6164 ssh->deferred_send_data = NULL;
6165 ssh->deferred_len = 0;
6166 ssh->deferred_size = 0;
6167 ssh->fallback_cmd = 0;
6168 ssh->pkt_ctx = 0;
6169 ssh->x11auth = NULL;
6170 ssh->v1_compressing = FALSE;
6171 ssh->v2_outgoing_sequence = 0;
6172 ssh->ssh1_rdpkt_crstate = 0;
6173 ssh->ssh2_rdpkt_crstate = 0;
6174 ssh->do_ssh_init_crstate = 0;
6175 ssh->ssh_gotdata_crstate = 0;
6176 ssh->ssh1_protocol_crstate = 0;
6177 ssh->do_ssh1_login_crstate = 0;
6178 ssh->do_ssh2_transport_crstate = 0;
6179 ssh->do_ssh2_authconn_crstate = 0;
6180 ssh->do_ssh_init_state = NULL;
6181 ssh->do_ssh1_login_state = NULL;
6182 ssh->do_ssh2_transport_state = NULL;
6183 ssh->do_ssh2_authconn_state = NULL;
6184 ssh->mainchan = NULL;
6185 ssh->throttled_all = 0;
6186 ssh->v1_stdout_throttling = 0;
6187
6188 *backend_handle = ssh;
6189
6190 #ifdef MSCRYPTOAPI
6191 if (crypto_startup() == 0)
6192 return "Microsoft high encryption pack not installed!";
6193 #endif
6194
6195 ssh->frontend = frontend_handle;
6196 ssh->term_width = ssh->cfg.width;
6197 ssh->term_height = ssh->cfg.height;
6198
6199 ssh->channels = NULL;
6200 ssh->rportfwds = NULL;
6201
6202 ssh->send_ok = 0;
6203 ssh->editing = 0;
6204 ssh->echoing = 0;
6205 ssh->v1_throttle_count = 0;
6206 ssh->overall_bufsize = 0;
6207 ssh->fallback_cmd = 0;
6208
6209 ssh->protocol = NULL;
6210
6211 p = connect_to_host(ssh, host, port, realhost, nodelay);
6212 if (p != NULL)
6213 return p;
6214
6215 return NULL;
6216 }
6217
6218 static void ssh_free(void *handle)
6219 {
6220 Ssh ssh = (Ssh) handle;
6221 struct ssh_channel *c;
6222 struct ssh_rportfwd *pf;
6223
6224 if (ssh->v1_cipher_ctx)
6225 ssh->cipher->free_context(ssh->v1_cipher_ctx);
6226 if (ssh->cs_cipher_ctx)
6227 ssh->cscipher->free_context(ssh->cs_cipher_ctx);
6228 if (ssh->sc_cipher_ctx)
6229 ssh->sccipher->free_context(ssh->sc_cipher_ctx);
6230 if (ssh->cs_mac_ctx)
6231 ssh->csmac->free_context(ssh->cs_mac_ctx);
6232 if (ssh->sc_mac_ctx)
6233 ssh->scmac->free_context(ssh->sc_mac_ctx);
6234 if (ssh->cs_comp_ctx)
6235 ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
6236 if (ssh->sc_comp_ctx)
6237 ssh->sccomp->compress_cleanup(ssh->sc_comp_ctx);
6238 if (ssh->kex_ctx)
6239 dh_cleanup(ssh->kex_ctx);
6240 sfree(ssh->savedhost);
6241
6242 if (ssh->channels) {
6243 while ((c = delpos234(ssh->channels, 0)) != NULL) {
6244 switch (c->type) {
6245 case CHAN_X11:
6246 if (c->u.x11.s != NULL)
6247 x11_close(c->u.x11.s);
6248 break;
6249 case CHAN_SOCKDATA:
6250 if (c->u.pfd.s != NULL)
6251 pfd_close(c->u.pfd.s);
6252 break;
6253 }
6254 sfree(c);
6255 }
6256 freetree234(ssh->channels);
6257 }
6258
6259 if (ssh->rportfwds) {
6260 while ((pf = delpos234(ssh->rportfwds, 0)) != NULL)
6261 sfree(pf);
6262 freetree234(ssh->rportfwds);
6263 }
6264 sfree(ssh->deferred_send_data);
6265 if (ssh->x11auth)
6266 x11_free_auth(ssh->x11auth);
6267 sfree(ssh->do_ssh_init_state);
6268 sfree(ssh->do_ssh1_login_state);
6269 sfree(ssh->do_ssh2_transport_state);
6270 sfree(ssh->do_ssh2_authconn_state);
6271
6272 if (ssh->s)
6273 ssh_do_close(ssh);
6274 sfree(ssh);
6275 }
6276
6277 /*
6278 * Reconfigure the SSH backend.
6279 *
6280 * Currently, this function does nothing very useful. In future,
6281 * however, we could do some handy things with it. For example, we
6282 * could make the port forwarding configurer active in the Change
6283 * Settings box, and this routine could close down existing
6284 * forwardings and open up new ones in response to changes.
6285 */
6286 static void ssh_reconfig(void *handle, Config *cfg)
6287 {
6288 Ssh ssh = (Ssh) handle;
6289 ssh->cfg = *cfg; /* STRUCTURE COPY */
6290 }
6291
6292 /*
6293 * Called to send data down the Telnet connection.
6294 */
6295 static int ssh_send(void *handle, char *buf, int len)
6296 {
6297 Ssh ssh = (Ssh) handle;
6298
6299 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
6300 return 0;
6301
6302 ssh->protocol(ssh, (unsigned char *)buf, len, 0);
6303
6304 return ssh_sendbuffer(ssh);
6305 }
6306
6307 /*
6308 * Called to query the current amount of buffered stdin data.
6309 */
6310 static int ssh_sendbuffer(void *handle)
6311 {
6312 Ssh ssh = (Ssh) handle;
6313 int override_value;
6314
6315 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
6316 return 0;
6317
6318 /*
6319 * If the SSH socket itself has backed up, add the total backup
6320 * size on that to any individual buffer on the stdin channel.
6321 */
6322 override_value = 0;
6323 if (ssh->throttled_all)
6324 override_value = ssh->overall_bufsize;
6325
6326 if (ssh->version == 1) {
6327 return override_value;
6328 } else if (ssh->version == 2) {
6329 if (!ssh->mainchan || ssh->mainchan->closes > 0)
6330 return override_value;
6331 else
6332 return (override_value +
6333 bufchain_size(&ssh->mainchan->v.v2.outbuffer));
6334 }
6335
6336 return 0;
6337 }
6338
6339 /*
6340 * Called to set the size of the window from SSH's POV.
6341 */
6342 static void ssh_size(void *handle, int width, int height)
6343 {
6344 Ssh ssh = (Ssh) handle;
6345
6346 ssh->term_width = width;
6347 ssh->term_height = height;
6348
6349 switch (ssh->state) {
6350 case SSH_STATE_BEFORE_SIZE:
6351 case SSH_STATE_PREPACKET:
6352 case SSH_STATE_CLOSED:
6353 break; /* do nothing */
6354 case SSH_STATE_INTERMED:
6355 ssh->size_needed = TRUE; /* buffer for later */
6356 break;
6357 case SSH_STATE_SESSION:
6358 if (!ssh->cfg.nopty) {
6359 if (ssh->version == 1) {
6360 send_packet(ssh, SSH1_CMSG_WINDOW_SIZE,
6361 PKT_INT, ssh->term_height,
6362 PKT_INT, ssh->term_width,
6363 PKT_INT, 0, PKT_INT, 0, PKT_END);
6364 } else {
6365 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
6366 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
6367 ssh2_pkt_addstring(ssh, "window-change");
6368 ssh2_pkt_addbool(ssh, 0);
6369 ssh2_pkt_adduint32(ssh, ssh->term_width);
6370 ssh2_pkt_adduint32(ssh, ssh->term_height);
6371 ssh2_pkt_adduint32(ssh, 0);
6372 ssh2_pkt_adduint32(ssh, 0);
6373 ssh2_pkt_send(ssh);
6374 }
6375 }
6376 break;
6377 }
6378 }
6379
6380 /*
6381 * Return a list of the special codes that make sense in this
6382 * protocol.
6383 */
6384 static const struct telnet_special *ssh_get_specials(void *handle)
6385 {
6386 Ssh ssh = (Ssh) handle;
6387
6388 if (ssh->version == 1) {
6389 static const struct telnet_special ssh1_specials[] = {
6390 {"IGNORE message", TS_NOP},
6391 {NULL, 0}
6392 };
6393 return ssh1_specials;
6394 } else if (ssh->version == 2) {
6395 static const struct telnet_special ssh2_specials[] = {
6396 {"Break", TS_BRK},
6397 {"IGNORE message", TS_NOP},
6398 {NULL, 0}
6399 };
6400 return ssh2_specials;
6401 } else
6402 return NULL;
6403 }
6404
6405 /*
6406 * Send Telnet special codes. TS_EOF is useful for `plink', so you
6407 * can send an EOF and collect resulting output (e.g. `plink
6408 * hostname sort').
6409 */
6410 static void ssh_special(void *handle, Telnet_Special code)
6411 {
6412 Ssh ssh = (Ssh) handle;
6413
6414 if (code == TS_EOF) {
6415 if (ssh->state != SSH_STATE_SESSION) {
6416 /*
6417 * Buffer the EOF in case we are pre-SESSION, so we can
6418 * send it as soon as we reach SESSION.
6419 */
6420 if (code == TS_EOF)
6421 ssh->eof_needed = TRUE;
6422 return;
6423 }
6424 if (ssh->version == 1) {
6425 send_packet(ssh, SSH1_CMSG_EOF, PKT_END);
6426 } else {
6427 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_EOF);
6428 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
6429 ssh2_pkt_send(ssh);
6430 }
6431 logevent("Sent EOF message");
6432 } else if (code == TS_PING || code == TS_NOP) {
6433 if (ssh->state == SSH_STATE_CLOSED
6434 || ssh->state == SSH_STATE_PREPACKET) return;
6435 if (ssh->version == 1) {
6436 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE))
6437 send_packet(ssh, SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
6438 } else {
6439 ssh2_pkt_init(ssh, SSH2_MSG_IGNORE);
6440 ssh2_pkt_addstring_start(ssh);
6441 ssh2_pkt_send(ssh);
6442 }
6443 } else if (code == TS_BRK) {
6444 if (ssh->state == SSH_STATE_CLOSED
6445 || ssh->state == SSH_STATE_PREPACKET) return;
6446 if (ssh->version == 1) {
6447 logevent("Unable to send BREAK signal in SSH1");
6448 } else {
6449 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
6450 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
6451 ssh2_pkt_addstring(ssh, "break");
6452 ssh2_pkt_addbool(ssh, 0);
6453 ssh2_pkt_adduint32(ssh, 0); /* default break length */
6454 ssh2_pkt_send(ssh);
6455 }
6456 } else {
6457 /* do nothing */
6458 }
6459 }
6460
6461 void *new_sock_channel(void *handle, Socket s)
6462 {
6463 Ssh ssh = (Ssh) handle;
6464 struct ssh_channel *c;
6465 c = snew(struct ssh_channel);
6466 c->ssh = ssh;
6467
6468 if (c) {
6469 c->remoteid = -1; /* to be set when open confirmed */
6470 c->localid = alloc_channel_id(ssh);
6471 c->closes = 0;
6472 c->type = CHAN_SOCKDATA_DORMANT;/* identify channel type */
6473 c->u.pfd.s = s;
6474 bufchain_init(&c->v.v2.outbuffer);
6475 add234(ssh->channels, c);
6476 }
6477 return c;
6478 }
6479
6480 /*
6481 * This is called when stdout/stderr (the entity to which
6482 * from_backend sends data) manages to clear some backlog.
6483 */
6484 static void ssh_unthrottle(void *handle, int bufsize)
6485 {
6486 Ssh ssh = (Ssh) handle;
6487 if (ssh->version == 1) {
6488 if (ssh->v1_stdout_throttling && bufsize < SSH1_BUFFER_LIMIT) {
6489 ssh->v1_stdout_throttling = 0;
6490 ssh1_throttle(ssh, -1);
6491 }
6492 } else {
6493 if (ssh->mainchan && ssh->mainchan->closes == 0)
6494 ssh2_set_window(ssh->mainchan, OUR_V2_WINSIZE - bufsize);
6495 }
6496 }
6497
6498 void ssh_send_port_open(void *channel, char *hostname, int port, char *org)
6499 {
6500 struct ssh_channel *c = (struct ssh_channel *)channel;
6501 Ssh ssh = c->ssh;
6502
6503 logeventf(ssh, "Opening forwarded connection to %s:%d", hostname, port);
6504
6505 if (ssh->version == 1) {
6506 send_packet(ssh, SSH1_MSG_PORT_OPEN,
6507 PKT_INT, c->localid,
6508 PKT_STR, hostname,
6509 PKT_INT, port,
6510 //PKT_STR, <org:orgport>,
6511 PKT_END);
6512 } else {
6513 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN);
6514 ssh2_pkt_addstring(ssh, "direct-tcpip");
6515 ssh2_pkt_adduint32(ssh, c->localid);
6516 c->v.v2.locwindow = OUR_V2_WINSIZE;
6517 ssh2_pkt_adduint32(ssh, c->v.v2.locwindow);/* our window size */
6518 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
6519 ssh2_pkt_addstring(ssh, hostname);
6520 ssh2_pkt_adduint32(ssh, port);
6521 /*
6522 * We make up values for the originator data; partly it's
6523 * too much hassle to keep track, and partly I'm not
6524 * convinced the server should be told details like that
6525 * about my local network configuration.
6526 */
6527 ssh2_pkt_addstring(ssh, "client-side-connection");
6528 ssh2_pkt_adduint32(ssh, 0);
6529 ssh2_pkt_send(ssh);
6530 }
6531 }
6532
6533
6534 static Socket ssh_socket(void *handle)
6535 {
6536 Ssh ssh = (Ssh) handle;
6537 return ssh->s;
6538 }
6539
6540 static int ssh_sendok(void *handle)
6541 {
6542 Ssh ssh = (Ssh) handle;
6543 return ssh->send_ok;
6544 }
6545
6546 static int ssh_ldisc(void *handle, int option)
6547 {
6548 Ssh ssh = (Ssh) handle;
6549 if (option == LD_ECHO)
6550 return ssh->echoing;
6551 if (option == LD_EDIT)
6552 return ssh->editing;
6553 return FALSE;
6554 }
6555
6556 static void ssh_provide_ldisc(void *handle, void *ldisc)
6557 {
6558 Ssh ssh = (Ssh) handle;
6559 ssh->ldisc = ldisc;
6560 }
6561
6562 static void ssh_provide_logctx(void *handle, void *logctx)
6563 {
6564 Ssh ssh = (Ssh) handle;
6565 ssh->logctx = logctx;
6566 }
6567
6568 static int ssh_return_exitcode(void *handle)
6569 {
6570 Ssh ssh = (Ssh) handle;
6571 if (ssh->s != NULL)
6572 return -1;
6573 else
6574 return (ssh->exitcode >= 0 ? ssh->exitcode : 0);
6575 }
6576
6577 /*
6578 * Gross hack: pscp will try to start SFTP but fall back to scp1 if
6579 * that fails. This variable is the means by which scp.c can reach
6580 * into the SSH code and find out which one it got.
6581 */
6582 extern int ssh_fallback_cmd(void *handle)
6583 {
6584 Ssh ssh = (Ssh) handle;
6585 return ssh->fallback_cmd;
6586 }
6587
6588 Backend ssh_backend = {
6589 ssh_init,
6590 ssh_free,
6591 ssh_reconfig,
6592 ssh_send,
6593 ssh_sendbuffer,
6594 ssh_size,
6595 ssh_special,
6596 ssh_get_specials,
6597 ssh_socket,
6598 ssh_return_exitcode,
6599 ssh_sendok,
6600 ssh_ldisc,
6601 ssh_provide_ldisc,
6602 ssh_provide_logctx,
6603 ssh_unthrottle,
6604 22
6605 };
Local modifications for Simon Tatham's `PuTTY' SSH client and terminal emulator