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Add a configuration option for TCP keepalives (SO_KEEPALIVE), default off.
[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 ospeed, ispeed; /* temporaries */
577 int term_width, term_height;
578
579 tree234 *channels; /* indexed by local id */
580 struct ssh_channel *mainchan; /* primary session channel */
581 int exitcode;
582
583 tree234 *rportfwds;
584
585 enum {
586 SSH_STATE_PREPACKET,
587 SSH_STATE_BEFORE_SIZE,
588 SSH_STATE_INTERMED,
589 SSH_STATE_SESSION,
590 SSH_STATE_CLOSED
591 } state;
592
593 int size_needed, eof_needed;
594
595 struct Packet pktin;
596 struct Packet pktout;
597 unsigned char *deferred_send_data;
598 int deferred_len, deferred_size;
599
600 /*
601 * Gross hack: pscp will try to start SFTP but fall back to
602 * scp1 if that fails. This variable is the means by which
603 * scp.c can reach into the SSH code and find out which one it
604 * got.
605 */
606 int fallback_cmd;
607
608 /*
609 * Used for username and password input.
610 */
611 char *userpass_input_buffer;
612 int userpass_input_buflen;
613 int userpass_input_bufpos;
614 int userpass_input_echo;
615
616 char *portfwd_strptr;
617 int pkt_ctx;
618
619 void *x11auth;
620
621 int version;
622 int v1_throttle_count;
623 int overall_bufsize;
624 int throttled_all;
625 int v1_stdout_throttling;
626 int v2_outgoing_sequence;
627
628 int ssh1_rdpkt_crstate;
629 int ssh2_rdpkt_crstate;
630 int do_ssh_init_crstate;
631 int ssh_gotdata_crstate;
632 int ssh1_protocol_crstate;
633 int do_ssh1_login_crstate;
634 int do_ssh2_transport_crstate;
635 int do_ssh2_authconn_crstate;
636
637 void *do_ssh_init_state;
638 void *do_ssh1_login_state;
639 void *do_ssh2_transport_state;
640 void *do_ssh2_authconn_state;
641
642 struct rdpkt1_state_tag rdpkt1_state;
643 struct rdpkt2_state_tag rdpkt2_state;
644
645 void (*protocol) (Ssh ssh, unsigned char *in, int inlen, int ispkt);
646 int (*s_rdpkt) (Ssh ssh, unsigned char **data, int *datalen);
647
648 /*
649 * We maintain a full _copy_ of a Config structure here, not
650 * merely a pointer to it. That way, when we're passed a new
651 * one for reconfiguration, we can check the differences and
652 * potentially reconfigure port forwardings etc in mid-session.
653 */
654 Config cfg;
655
656 /*
657 * Used to transfer data back from async agent callbacks.
658 */
659 void *agent_response;
660 int agent_response_len;
661 };
662
663 #define logevent(s) logevent(ssh->frontend, s)
664
665 /* logevent, only printf-formatted. */
666 static void logeventf(Ssh ssh, const char *fmt, ...)
667 {
668 va_list ap;
669 char *buf;
670
671 va_start(ap, fmt);
672 buf = dupvprintf(fmt, ap);
673 va_end(ap);
674 logevent(buf);
675 sfree(buf);
676 }
677
678 #define bombout(msg) \
679 do { \
680 char *text = dupprintf msg; \
681 ssh_do_close(ssh); \
682 logevent(text); \
683 connection_fatal(ssh->frontend, "%s", text); \
684 sfree(text); \
685 } while (0)
686
687 static int ssh_channelcmp(void *av, void *bv)
688 {
689 struct ssh_channel *a = (struct ssh_channel *) av;
690 struct ssh_channel *b = (struct ssh_channel *) bv;
691 if (a->localid < b->localid)
692 return -1;
693 if (a->localid > b->localid)
694 return +1;
695 return 0;
696 }
697 static int ssh_channelfind(void *av, void *bv)
698 {
699 unsigned *a = (unsigned *) av;
700 struct ssh_channel *b = (struct ssh_channel *) bv;
701 if (*a < b->localid)
702 return -1;
703 if (*a > b->localid)
704 return +1;
705 return 0;
706 }
707
708 static int ssh_rportcmp_ssh1(void *av, void *bv)
709 {
710 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
711 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
712 int i;
713 if ( (i = strcmp(a->dhost, b->dhost)) != 0)
714 return i < 0 ? -1 : +1;
715 if (a->dport > b->dport)
716 return +1;
717 if (a->dport < b->dport)
718 return -1;
719 return 0;
720 }
721
722 static int ssh_rportcmp_ssh2(void *av, void *bv)
723 {
724 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
725 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
726
727 if (a->sport > b->sport)
728 return +1;
729 if (a->sport < b->sport)
730 return -1;
731 return 0;
732 }
733
734 static int alloc_channel_id(Ssh ssh)
735 {
736 const unsigned CHANNEL_NUMBER_OFFSET = 256;
737 unsigned low, high, mid;
738 int tsize;
739 struct ssh_channel *c;
740
741 /*
742 * First-fit allocation of channel numbers: always pick the
743 * lowest unused one. To do this, binary-search using the
744 * counted B-tree to find the largest channel ID which is in a
745 * contiguous sequence from the beginning. (Precisely
746 * everything in that sequence must have ID equal to its tree
747 * index plus CHANNEL_NUMBER_OFFSET.)
748 */
749 tsize = count234(ssh->channels);
750
751 low = -1;
752 high = tsize;
753 while (high - low > 1) {
754 mid = (high + low) / 2;
755 c = index234(ssh->channels, mid);
756 if (c->localid == mid + CHANNEL_NUMBER_OFFSET)
757 low = mid; /* this one is fine */
758 else
759 high = mid; /* this one is past it */
760 }
761 /*
762 * Now low points to either -1, or the tree index of the
763 * largest ID in the initial sequence.
764 */
765 {
766 unsigned i = low + 1 + CHANNEL_NUMBER_OFFSET;
767 assert(NULL == find234(ssh->channels, &i, ssh_channelfind));
768 }
769 return low + 1 + CHANNEL_NUMBER_OFFSET;
770 }
771
772 static void c_write(Ssh ssh, const char *buf, int len)
773 {
774 if ((flags & FLAG_STDERR)) {
775 int i;
776 for (i = 0; i < len; i++)
777 if (buf[i] != '\r')
778 fputc(buf[i], stderr);
779 return;
780 }
781 from_backend(ssh->frontend, 1, buf, len);
782 }
783
784 static void c_write_untrusted(Ssh ssh, const char *buf, int len)
785 {
786 int i;
787 for (i = 0; i < len; i++) {
788 if (buf[i] == '\n')
789 c_write(ssh, "\r\n", 2);
790 else if ((buf[i] & 0x60) || (buf[i] == '\r'))
791 c_write(ssh, buf + i, 1);
792 }
793 }
794
795 static void c_write_str(Ssh ssh, const char *buf)
796 {
797 c_write(ssh, buf, strlen(buf));
798 }
799
800 /*
801 * Collect incoming data in the incoming packet buffer.
802 * Decipher and verify the packet when it is completely read.
803 * Drop SSH1_MSG_DEBUG and SSH1_MSG_IGNORE packets.
804 * Update the *data and *datalen variables.
805 * Return the additional nr of bytes needed, or 0 when
806 * a complete packet is available.
807 */
808 static int ssh1_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
809 {
810 struct rdpkt1_state_tag *st = &ssh->rdpkt1_state;
811
812 crBegin(ssh->ssh1_rdpkt_crstate);
813
814 next_packet:
815
816 ssh->pktin.type = 0;
817 ssh->pktin.length = 0;
818
819 for (st->i = st->len = 0; st->i < 4; st->i++) {
820 while ((*datalen) == 0)
821 crReturn(4 - st->i);
822 st->len = (st->len << 8) + **data;
823 (*data)++, (*datalen)--;
824 }
825
826 st->pad = 8 - (st->len % 8);
827 st->biglen = st->len + st->pad;
828 ssh->pktin.length = st->len - 5;
829
830 if (ssh->pktin.maxlen < st->biglen) {
831 ssh->pktin.maxlen = st->biglen;
832 ssh->pktin.data = sresize(ssh->pktin.data, st->biglen + APIEXTRA,
833 unsigned char);
834 }
835
836 st->to_read = st->biglen;
837 st->p = ssh->pktin.data;
838 while (st->to_read > 0) {
839 st->chunk = st->to_read;
840 while ((*datalen) == 0)
841 crReturn(st->to_read);
842 if (st->chunk > (*datalen))
843 st->chunk = (*datalen);
844 memcpy(st->p, *data, st->chunk);
845 *data += st->chunk;
846 *datalen -= st->chunk;
847 st->p += st->chunk;
848 st->to_read -= st->chunk;
849 }
850
851 if (ssh->cipher && detect_attack(ssh->crcda_ctx, ssh->pktin.data,
852 st->biglen, NULL)) {
853 bombout(("Network attack (CRC compensation) detected!"));
854 crStop(0);
855 }
856
857 if (ssh->cipher)
858 ssh->cipher->decrypt(ssh->v1_cipher_ctx, ssh->pktin.data, st->biglen);
859
860 st->realcrc = crc32_compute(ssh->pktin.data, st->biglen - 4);
861 st->gotcrc = GET_32BIT(ssh->pktin.data + st->biglen - 4);
862 if (st->gotcrc != st->realcrc) {
863 bombout(("Incorrect CRC received on packet"));
864 crStop(0);
865 }
866
867 ssh->pktin.body = ssh->pktin.data + st->pad + 1;
868
869 if (ssh->v1_compressing) {
870 unsigned char *decompblk;
871 int decomplen;
872 if (!zlib_decompress_block(ssh->sc_comp_ctx,
873 ssh->pktin.body - 1, ssh->pktin.length + 1,
874 &decompblk, &decomplen)) {
875 bombout(("Zlib decompression encountered invalid data"));
876 crStop(0);
877 }
878
879 if (ssh->pktin.maxlen < st->pad + decomplen) {
880 ssh->pktin.maxlen = st->pad + decomplen;
881 ssh->pktin.data = sresize(ssh->pktin.data,
882 ssh->pktin.maxlen + APIEXTRA,
883 unsigned char);
884 ssh->pktin.body = ssh->pktin.data + st->pad + 1;
885 }
886
887 memcpy(ssh->pktin.body - 1, decompblk, decomplen);
888 sfree(decompblk);
889 ssh->pktin.length = decomplen - 1;
890 }
891
892 ssh->pktin.type = ssh->pktin.body[-1];
893
894 if (ssh->logctx)
895 log_packet(ssh->logctx,
896 PKT_INCOMING, ssh->pktin.type,
897 ssh1_pkt_type(ssh->pktin.type),
898 ssh->pktin.body, ssh->pktin.length);
899
900 if (ssh->pktin.type == SSH1_SMSG_STDOUT_DATA ||
901 ssh->pktin.type == SSH1_SMSG_STDERR_DATA ||
902 ssh->pktin.type == SSH1_MSG_DEBUG ||
903 ssh->pktin.type == SSH1_SMSG_AUTH_TIS_CHALLENGE ||
904 ssh->pktin.type == SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
905 long stringlen = GET_32BIT(ssh->pktin.body);
906 if (stringlen + 4 != ssh->pktin.length) {
907 bombout(("Received data packet with bogus string length"));
908 crStop(0);
909 }
910 }
911
912 if (ssh->pktin.type == SSH1_MSG_DEBUG) {
913 /* log debug message */
914 char buf[512];
915 int stringlen = GET_32BIT(ssh->pktin.body);
916 strcpy(buf, "Remote debug message: ");
917 if (stringlen > 480)
918 stringlen = 480;
919 memcpy(buf + 8, ssh->pktin.body + 4, stringlen);
920 buf[8 + stringlen] = '\0';
921 logevent(buf);
922 goto next_packet;
923 } else if (ssh->pktin.type == SSH1_MSG_IGNORE) {
924 /* do nothing */
925 goto next_packet;
926 }
927
928 if (ssh->pktin.type == SSH1_MSG_DISCONNECT) {
929 /* log reason code in disconnect message */
930 char buf[256];
931 unsigned msglen = GET_32BIT(ssh->pktin.body);
932 unsigned nowlen;
933 strcpy(buf, "Remote sent disconnect: ");
934 nowlen = strlen(buf);
935 if (msglen > sizeof(buf) - nowlen - 1)
936 msglen = sizeof(buf) - nowlen - 1;
937 memcpy(buf + nowlen, ssh->pktin.body + 4, msglen);
938 buf[nowlen + msglen] = '\0';
939 /* logevent(buf); (this is now done within the bombout macro) */
940 bombout(("Server sent disconnect message:\n\"%s\"", buf+nowlen));
941 crStop(0);
942 }
943
944 crFinish(0);
945 }
946
947 static int ssh2_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
948 {
949 struct rdpkt2_state_tag *st = &ssh->rdpkt2_state;
950
951 crBegin(ssh->ssh2_rdpkt_crstate);
952
953 next_packet:
954 ssh->pktin.type = 0;
955 ssh->pktin.length = 0;
956 if (ssh->sccipher)
957 st->cipherblk = ssh->sccipher->blksize;
958 else
959 st->cipherblk = 8;
960 if (st->cipherblk < 8)
961 st->cipherblk = 8;
962
963 if (ssh->pktin.maxlen < st->cipherblk) {
964 ssh->pktin.maxlen = st->cipherblk;
965 ssh->pktin.data = sresize(ssh->pktin.data, st->cipherblk + APIEXTRA,
966 unsigned char);
967 }
968
969 /*
970 * Acquire and decrypt the first block of the packet. This will
971 * contain the length and padding details.
972 */
973 for (st->i = st->len = 0; st->i < st->cipherblk; st->i++) {
974 while ((*datalen) == 0)
975 crReturn(st->cipherblk - st->i);
976 ssh->pktin.data[st->i] = *(*data)++;
977 (*datalen)--;
978 }
979
980 if (ssh->sccipher)
981 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
982 ssh->pktin.data, st->cipherblk);
983
984 /*
985 * Now get the length and padding figures.
986 */
987 st->len = GET_32BIT(ssh->pktin.data);
988 st->pad = ssh->pktin.data[4];
989
990 /*
991 * _Completely_ silly lengths should be stomped on before they
992 * do us any more damage.
993 */
994 if (st->len < 0 || st->pad < 0 || st->len + st->pad < 0) {
995 bombout(("Incoming packet was garbled on decryption"));
996 crStop(0);
997 }
998
999 /*
1000 * This enables us to deduce the payload length.
1001 */
1002 st->payload = st->len - st->pad - 1;
1003
1004 ssh->pktin.length = st->payload + 5;
1005
1006 /*
1007 * So now we can work out the total packet length.
1008 */
1009 st->packetlen = st->len + 4;
1010 st->maclen = ssh->scmac ? ssh->scmac->len : 0;
1011
1012 /*
1013 * Adjust memory allocation if packet is too big.
1014 */
1015 if (ssh->pktin.maxlen < st->packetlen + st->maclen) {
1016 ssh->pktin.maxlen = st->packetlen + st->maclen;
1017 ssh->pktin.data = sresize(ssh->pktin.data,
1018 ssh->pktin.maxlen + APIEXTRA,
1019 unsigned char);
1020 }
1021
1022 /*
1023 * Read and decrypt the remainder of the packet.
1024 */
1025 for (st->i = st->cipherblk; st->i < st->packetlen + st->maclen;
1026 st->i++) {
1027 while ((*datalen) == 0)
1028 crReturn(st->packetlen + st->maclen - st->i);
1029 ssh->pktin.data[st->i] = *(*data)++;
1030 (*datalen)--;
1031 }
1032 /* Decrypt everything _except_ the MAC. */
1033 if (ssh->sccipher)
1034 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
1035 ssh->pktin.data + st->cipherblk,
1036 st->packetlen - st->cipherblk);
1037
1038 /*
1039 * Check the MAC.
1040 */
1041 if (ssh->scmac
1042 && !ssh->scmac->verify(ssh->sc_mac_ctx, ssh->pktin.data, st->len + 4,
1043 st->incoming_sequence)) {
1044 bombout(("Incorrect MAC received on packet"));
1045 crStop(0);
1046 }
1047 st->incoming_sequence++; /* whether or not we MACed */
1048
1049 /*
1050 * Decompress packet payload.
1051 */
1052 {
1053 unsigned char *newpayload;
1054 int newlen;
1055 if (ssh->sccomp &&
1056 ssh->sccomp->decompress(ssh->sc_comp_ctx,
1057 ssh->pktin.data + 5, ssh->pktin.length - 5,
1058 &newpayload, &newlen)) {
1059 if (ssh->pktin.maxlen < newlen + 5) {
1060 ssh->pktin.maxlen = newlen + 5;
1061 ssh->pktin.data = sresize(ssh->pktin.data,
1062 ssh->pktin.maxlen + APIEXTRA,
1063 unsigned char);
1064 }
1065 ssh->pktin.length = 5 + newlen;
1066 memcpy(ssh->pktin.data + 5, newpayload, newlen);
1067 sfree(newpayload);
1068 }
1069 }
1070
1071 ssh->pktin.savedpos = 6;
1072 ssh->pktin.type = ssh->pktin.data[5];
1073
1074 if (ssh->logctx)
1075 log_packet(ssh->logctx, PKT_INCOMING, ssh->pktin.type,
1076 ssh2_pkt_type(ssh->pkt_ctx, ssh->pktin.type),
1077 ssh->pktin.data+6, ssh->pktin.length-6);
1078
1079 switch (ssh->pktin.type) {
1080 /*
1081 * These packets we must handle instantly.
1082 */
1083 case SSH2_MSG_DISCONNECT:
1084 {
1085 /* log reason code in disconnect message */
1086 char *buf;
1087 int nowlen;
1088 int reason = GET_32BIT(ssh->pktin.data + 6);
1089 unsigned msglen = GET_32BIT(ssh->pktin.data + 10);
1090
1091 if (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) {
1092 buf = dupprintf("Received disconnect message (%s)",
1093 ssh2_disconnect_reasons[reason]);
1094 } else {
1095 buf = dupprintf("Received disconnect message (unknown"
1096 " type %d)", reason);
1097 }
1098 logevent(buf);
1099 sfree(buf);
1100 buf = dupprintf("Disconnection message text: %n%.*s",
1101 &nowlen, msglen, ssh->pktin.data + 14);
1102 logevent(buf);
1103 bombout(("Server sent disconnect message\ntype %d (%s):\n\"%s\"",
1104 reason,
1105 (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) ?
1106 ssh2_disconnect_reasons[reason] : "unknown",
1107 buf+nowlen));
1108 sfree(buf);
1109 crStop(0);
1110 }
1111 break;
1112 case SSH2_MSG_IGNORE:
1113 goto next_packet;
1114 case SSH2_MSG_DEBUG:
1115 {
1116 /* log the debug message */
1117 char buf[512];
1118 /* int display = ssh->pktin.body[6]; */
1119 int stringlen = GET_32BIT(ssh->pktin.data+7);
1120 int prefix;
1121 strcpy(buf, "Remote debug message: ");
1122 prefix = strlen(buf);
1123 if (stringlen > (int)(sizeof(buf)-prefix-1))
1124 stringlen = sizeof(buf)-prefix-1;
1125 memcpy(buf + prefix, ssh->pktin.data + 11, stringlen);
1126 buf[prefix + stringlen] = '\0';
1127 logevent(buf);
1128 }
1129 goto next_packet; /* FIXME: print the debug message */
1130
1131 /*
1132 * These packets we need do nothing about here.
1133 */
1134 case SSH2_MSG_UNIMPLEMENTED:
1135 case SSH2_MSG_SERVICE_REQUEST:
1136 case SSH2_MSG_SERVICE_ACCEPT:
1137 case SSH2_MSG_KEXINIT:
1138 case SSH2_MSG_NEWKEYS:
1139 case SSH2_MSG_KEXDH_INIT:
1140 case SSH2_MSG_KEXDH_REPLY:
1141 /* case SSH2_MSG_KEX_DH_GEX_REQUEST: duplicate case value */
1142 /* case SSH2_MSG_KEX_DH_GEX_GROUP: duplicate case value */
1143 case SSH2_MSG_KEX_DH_GEX_INIT:
1144 case SSH2_MSG_KEX_DH_GEX_REPLY:
1145 case SSH2_MSG_USERAUTH_REQUEST:
1146 case SSH2_MSG_USERAUTH_FAILURE:
1147 case SSH2_MSG_USERAUTH_SUCCESS:
1148 case SSH2_MSG_USERAUTH_BANNER:
1149 case SSH2_MSG_USERAUTH_PK_OK:
1150 /* case SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ: duplicate case value */
1151 /* case SSH2_MSG_USERAUTH_INFO_REQUEST: duplicate case value */
1152 case SSH2_MSG_USERAUTH_INFO_RESPONSE:
1153 case SSH2_MSG_GLOBAL_REQUEST:
1154 case SSH2_MSG_REQUEST_SUCCESS:
1155 case SSH2_MSG_REQUEST_FAILURE:
1156 case SSH2_MSG_CHANNEL_OPEN:
1157 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION:
1158 case SSH2_MSG_CHANNEL_OPEN_FAILURE:
1159 case SSH2_MSG_CHANNEL_WINDOW_ADJUST:
1160 case SSH2_MSG_CHANNEL_DATA:
1161 case SSH2_MSG_CHANNEL_EXTENDED_DATA:
1162 case SSH2_MSG_CHANNEL_EOF:
1163 case SSH2_MSG_CHANNEL_CLOSE:
1164 case SSH2_MSG_CHANNEL_REQUEST:
1165 case SSH2_MSG_CHANNEL_SUCCESS:
1166 case SSH2_MSG_CHANNEL_FAILURE:
1167 break;
1168
1169 /*
1170 * For anything else we send SSH2_MSG_UNIMPLEMENTED.
1171 */
1172 default:
1173 ssh2_pkt_init(ssh, SSH2_MSG_UNIMPLEMENTED);
1174 ssh2_pkt_adduint32(ssh, st->incoming_sequence - 1);
1175 ssh2_pkt_send(ssh);
1176 break;
1177 }
1178
1179 crFinish(0);
1180 }
1181
1182 static void ssh1_pktout_size(Ssh ssh, int len)
1183 {
1184 int pad, biglen;
1185
1186 len += 5; /* type and CRC */
1187 pad = 8 - (len % 8);
1188 biglen = len + pad;
1189
1190 ssh->pktout.length = len - 5;
1191 if (ssh->pktout.maxlen < biglen) {
1192 ssh->pktout.maxlen = biglen;
1193 #ifdef MSCRYPTOAPI
1194 /* Allocate enough buffer space for extra block
1195 * for MS CryptEncrypt() */
1196 ssh->pktout.data = sresize(ssh->pktout.data, biglen + 12,
1197 unsigned char);
1198 #else
1199 ssh->pktout.data = sresize(ssh->pktout.data, biglen + 4,
1200 unsigned char);
1201 #endif
1202 }
1203 ssh->pktout.body = ssh->pktout.data + 4 + pad + 1;
1204 }
1205
1206 static void s_wrpkt_start(Ssh ssh, int type, int len)
1207 {
1208 ssh1_pktout_size(ssh, len);
1209 ssh->pktout.type = type;
1210 }
1211
1212 static int s_wrpkt_prepare(Ssh ssh)
1213 {
1214 int pad, biglen, i;
1215 unsigned long crc;
1216 #ifdef __SC__
1217 /*
1218 * XXX various versions of SC (including 8.8.4) screw up the
1219 * register allocation in this function and use the same register
1220 * (D6) for len and as a temporary, with predictable results. The
1221 * following sledgehammer prevents this.
1222 */
1223 volatile
1224 #endif
1225 int len;
1226
1227 ssh->pktout.body[-1] = ssh->pktout.type;
1228
1229 if (ssh->logctx)
1230 log_packet(ssh->logctx, PKT_OUTGOING, ssh->pktout.type,
1231 ssh1_pkt_type(ssh->pktout.type),
1232 ssh->pktout.body, ssh->pktout.length);
1233
1234 if (ssh->v1_compressing) {
1235 unsigned char *compblk;
1236 int complen;
1237 zlib_compress_block(ssh->cs_comp_ctx,
1238 ssh->pktout.body - 1, ssh->pktout.length + 1,
1239 &compblk, &complen);
1240 ssh1_pktout_size(ssh, complen - 1);
1241 memcpy(ssh->pktout.body - 1, compblk, complen);
1242 sfree(compblk);
1243 }
1244
1245 len = ssh->pktout.length + 5; /* type and CRC */
1246 pad = 8 - (len % 8);
1247 biglen = len + pad;
1248
1249 for (i = 0; i < pad; i++)
1250 ssh->pktout.data[i + 4] = random_byte();
1251 crc = crc32_compute(ssh->pktout.data + 4, biglen - 4);
1252 PUT_32BIT(ssh->pktout.data + biglen, crc);
1253 PUT_32BIT(ssh->pktout.data, len);
1254
1255 if (ssh->cipher)
1256 ssh->cipher->encrypt(ssh->v1_cipher_ctx, ssh->pktout.data + 4, biglen);
1257
1258 return biglen + 4;
1259 }
1260
1261 static void s_wrpkt(Ssh ssh)
1262 {
1263 int len, backlog;
1264 len = s_wrpkt_prepare(ssh);
1265 backlog = sk_write(ssh->s, (char *)ssh->pktout.data, len);
1266 if (backlog > SSH_MAX_BACKLOG)
1267 ssh_throttle_all(ssh, 1, backlog);
1268 }
1269
1270 static void s_wrpkt_defer(Ssh ssh)
1271 {
1272 int len;
1273 len = s_wrpkt_prepare(ssh);
1274 if (ssh->deferred_len + len > ssh->deferred_size) {
1275 ssh->deferred_size = ssh->deferred_len + len + 128;
1276 ssh->deferred_send_data = sresize(ssh->deferred_send_data,
1277 ssh->deferred_size,
1278 unsigned char);
1279 }
1280 memcpy(ssh->deferred_send_data + ssh->deferred_len, ssh->pktout.data, len);
1281 ssh->deferred_len += len;
1282 }
1283
1284 /*
1285 * Construct a packet with the specified contents.
1286 */
1287 static void construct_packet(Ssh ssh, int pkttype, va_list ap1, va_list ap2)
1288 {
1289 unsigned char *p, *argp, argchar;
1290 unsigned long argint;
1291 int pktlen, argtype, arglen;
1292 Bignum bn;
1293
1294 pktlen = 0;
1295 while ((argtype = va_arg(ap1, int)) != PKT_END) {
1296 switch (argtype) {
1297 case PKT_INT:
1298 (void) va_arg(ap1, int);
1299 pktlen += 4;
1300 break;
1301 case PKT_CHAR:
1302 (void) va_arg(ap1, int);
1303 pktlen++;
1304 break;
1305 case PKT_DATA:
1306 (void) va_arg(ap1, unsigned char *);
1307 arglen = va_arg(ap1, int);
1308 pktlen += arglen;
1309 break;
1310 case PKT_STR:
1311 argp = va_arg(ap1, unsigned char *);
1312 arglen = strlen((char *)argp);
1313 pktlen += 4 + arglen;
1314 break;
1315 case PKT_BIGNUM:
1316 bn = va_arg(ap1, Bignum);
1317 pktlen += ssh1_bignum_length(bn);
1318 break;
1319 default:
1320 assert(0);
1321 }
1322 }
1323
1324 s_wrpkt_start(ssh, pkttype, pktlen);
1325 p = ssh->pktout.body;
1326
1327 while ((argtype = va_arg(ap2, int)) != PKT_END) {
1328 switch (argtype) {
1329 case PKT_INT:
1330 argint = va_arg(ap2, int);
1331 PUT_32BIT(p, argint);
1332 p += 4;
1333 break;
1334 case PKT_CHAR:
1335 argchar = (unsigned char) va_arg(ap2, int);
1336 *p = argchar;
1337 p++;
1338 break;
1339 case PKT_DATA:
1340 argp = va_arg(ap2, unsigned char *);
1341 arglen = va_arg(ap2, int);
1342 memcpy(p, argp, arglen);
1343 p += arglen;
1344 break;
1345 case PKT_STR:
1346 argp = va_arg(ap2, unsigned char *);
1347 arglen = strlen((char *)argp);
1348 PUT_32BIT(p, arglen);
1349 memcpy(p + 4, argp, arglen);
1350 p += 4 + arglen;
1351 break;
1352 case PKT_BIGNUM:
1353 bn = va_arg(ap2, Bignum);
1354 p += ssh1_write_bignum(p, bn);
1355 break;
1356 }
1357 }
1358 }
1359
1360 static void send_packet(Ssh ssh, int pkttype, ...)
1361 {
1362 va_list ap1, ap2;
1363 va_start(ap1, pkttype);
1364 va_start(ap2, pkttype);
1365 construct_packet(ssh, pkttype, ap1, ap2);
1366 s_wrpkt(ssh);
1367 }
1368
1369 static void defer_packet(Ssh ssh, int pkttype, ...)
1370 {
1371 va_list ap1, ap2;
1372 va_start(ap1, pkttype);
1373 va_start(ap2, pkttype);
1374 construct_packet(ssh, pkttype, ap1, ap2);
1375 s_wrpkt_defer(ssh);
1376 }
1377
1378 static int ssh_versioncmp(char *a, char *b)
1379 {
1380 char *ae, *be;
1381 unsigned long av, bv;
1382
1383 av = strtoul(a, &ae, 10);
1384 bv = strtoul(b, &be, 10);
1385 if (av != bv)
1386 return (av < bv ? -1 : +1);
1387 if (*ae == '.')
1388 ae++;
1389 if (*be == '.')
1390 be++;
1391 av = strtoul(ae, &ae, 10);
1392 bv = strtoul(be, &be, 10);
1393 if (av != bv)
1394 return (av < bv ? -1 : +1);
1395 return 0;
1396 }
1397
1398 /*
1399 * Utility routines for putting an SSH-protocol `string' and
1400 * `uint32' into a SHA state.
1401 */
1402 #include <stdio.h>
1403 static void sha_string(SHA_State * s, void *str, int len)
1404 {
1405 unsigned char lenblk[4];
1406 PUT_32BIT(lenblk, len);
1407 SHA_Bytes(s, lenblk, 4);
1408 SHA_Bytes(s, str, len);
1409 }
1410
1411 static void sha_uint32(SHA_State * s, unsigned i)
1412 {
1413 unsigned char intblk[4];
1414 PUT_32BIT(intblk, i);
1415 SHA_Bytes(s, intblk, 4);
1416 }
1417
1418 /*
1419 * SSH2 packet construction functions.
1420 */
1421 static void ssh2_pkt_ensure(Ssh ssh, int length)
1422 {
1423 if (ssh->pktout.maxlen < length) {
1424 ssh->pktout.maxlen = length + 256;
1425 ssh->pktout.data = sresize(ssh->pktout.data,
1426 ssh->pktout.maxlen + APIEXTRA,
1427 unsigned char);
1428 if (!ssh->pktout.data)
1429 fatalbox("Out of memory");
1430 }
1431 }
1432 static void ssh2_pkt_adddata(Ssh ssh, void *data, int len)
1433 {
1434 ssh->pktout.length += len;
1435 ssh2_pkt_ensure(ssh, ssh->pktout.length);
1436 memcpy(ssh->pktout.data + ssh->pktout.length - len, data, len);
1437 }
1438 static void ssh2_pkt_addbyte(Ssh ssh, unsigned char byte)
1439 {
1440 ssh2_pkt_adddata(ssh, &byte, 1);
1441 }
1442 static void ssh2_pkt_init(Ssh ssh, int pkt_type)
1443 {
1444 ssh->pktout.length = 5;
1445 ssh2_pkt_addbyte(ssh, (unsigned char) pkt_type);
1446 }
1447 static void ssh2_pkt_addbool(Ssh ssh, unsigned char value)
1448 {
1449 ssh2_pkt_adddata(ssh, &value, 1);
1450 }
1451 static void ssh2_pkt_adduint32(Ssh ssh, unsigned long value)
1452 {
1453 unsigned char x[4];
1454 PUT_32BIT(x, value);
1455 ssh2_pkt_adddata(ssh, x, 4);
1456 }
1457 static void ssh2_pkt_addstring_start(Ssh ssh)
1458 {
1459 ssh2_pkt_adduint32(ssh, 0);
1460 ssh->pktout.savedpos = ssh->pktout.length;
1461 }
1462 static void ssh2_pkt_addstring_str(Ssh ssh, char *data)
1463 {
1464 ssh2_pkt_adddata(ssh, data, strlen(data));
1465 PUT_32BIT(ssh->pktout.data + ssh->pktout.savedpos - 4,
1466 ssh->pktout.length - ssh->pktout.savedpos);
1467 }
1468 static void ssh2_pkt_addstring_data(Ssh ssh, char *data, int len)
1469 {
1470 ssh2_pkt_adddata(ssh, data, len);
1471 PUT_32BIT(ssh->pktout.data + ssh->pktout.savedpos - 4,
1472 ssh->pktout.length - ssh->pktout.savedpos);
1473 }
1474 static void ssh2_pkt_addstring(Ssh ssh, char *data)
1475 {
1476 ssh2_pkt_addstring_start(ssh);
1477 ssh2_pkt_addstring_str(ssh, data);
1478 }
1479 static unsigned char *ssh2_mpint_fmt(Bignum b, int *len)
1480 {
1481 unsigned char *p;
1482 int i, n = (bignum_bitcount(b) + 7) / 8;
1483 p = snewn(n + 1, unsigned char);
1484 if (!p)
1485 fatalbox("out of memory");
1486 p[0] = 0;
1487 for (i = 1; i <= n; i++)
1488 p[i] = bignum_byte(b, n - i);
1489 i = 0;
1490 while (i <= n && p[i] == 0 && (p[i + 1] & 0x80) == 0)
1491 i++;
1492 memmove(p, p + i, n + 1 - i);
1493 *len = n + 1 - i;
1494 return p;
1495 }
1496 static void ssh2_pkt_addmp(Ssh ssh, Bignum b)
1497 {
1498 unsigned char *p;
1499 int len;
1500 p = ssh2_mpint_fmt(b, &len);
1501 ssh2_pkt_addstring_start(ssh);
1502 ssh2_pkt_addstring_data(ssh, (char *)p, len);
1503 sfree(p);
1504 }
1505
1506 /*
1507 * Construct an SSH2 final-form packet: compress it, encrypt it,
1508 * put the MAC on it. Final packet, ready to be sent, is stored in
1509 * ssh->pktout.data. Total length is returned.
1510 */
1511 static int ssh2_pkt_construct(Ssh ssh)
1512 {
1513 int cipherblk, maclen, padding, i;
1514
1515 if (ssh->logctx)
1516 log_packet(ssh->logctx, PKT_OUTGOING, ssh->pktout.data[5],
1517 ssh2_pkt_type(ssh->pkt_ctx, ssh->pktout.data[5]),
1518 ssh->pktout.data + 6, ssh->pktout.length - 6);
1519
1520 /*
1521 * Compress packet payload.
1522 */
1523 {
1524 unsigned char *newpayload;
1525 int newlen;
1526 if (ssh->cscomp &&
1527 ssh->cscomp->compress(ssh->cs_comp_ctx, ssh->pktout.data + 5,
1528 ssh->pktout.length - 5,
1529 &newpayload, &newlen)) {
1530 ssh->pktout.length = 5;
1531 ssh2_pkt_adddata(ssh, newpayload, newlen);
1532 sfree(newpayload);
1533 }
1534 }
1535
1536 /*
1537 * Add padding. At least four bytes, and must also bring total
1538 * length (minus MAC) up to a multiple of the block size.
1539 */
1540 cipherblk = ssh->cscipher ? ssh->cscipher->blksize : 8; /* block size */
1541 cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */
1542 padding = 4;
1543 padding +=
1544 (cipherblk - (ssh->pktout.length + padding) % cipherblk) % cipherblk;
1545 maclen = ssh->csmac ? ssh->csmac->len : 0;
1546 ssh2_pkt_ensure(ssh, ssh->pktout.length + padding + maclen);
1547 ssh->pktout.data[4] = padding;
1548 for (i = 0; i < padding; i++)
1549 ssh->pktout.data[ssh->pktout.length + i] = random_byte();
1550 PUT_32BIT(ssh->pktout.data, ssh->pktout.length + padding - 4);
1551 if (ssh->csmac)
1552 ssh->csmac->generate(ssh->cs_mac_ctx, ssh->pktout.data,
1553 ssh->pktout.length + padding,
1554 ssh->v2_outgoing_sequence);
1555 ssh->v2_outgoing_sequence++; /* whether or not we MACed */
1556
1557 if (ssh->cscipher)
1558 ssh->cscipher->encrypt(ssh->cs_cipher_ctx,
1559 ssh->pktout.data, ssh->pktout.length + padding);
1560
1561 /* Ready-to-send packet starts at ssh->pktout.data. We return length. */
1562 return ssh->pktout.length + padding + maclen;
1563 }
1564
1565 /*
1566 * Construct and send an SSH2 packet immediately.
1567 */
1568 static void ssh2_pkt_send(Ssh ssh)
1569 {
1570 int len;
1571 int backlog;
1572 len = ssh2_pkt_construct(ssh);
1573 backlog = sk_write(ssh->s, (char *)ssh->pktout.data, len);
1574 if (backlog > SSH_MAX_BACKLOG)
1575 ssh_throttle_all(ssh, 1, backlog);
1576 }
1577
1578 /*
1579 * Construct an SSH2 packet and add it to a deferred data block.
1580 * Useful for sending multiple packets in a single sk_write() call,
1581 * to prevent a traffic-analysing listener from being able to work
1582 * out the length of any particular packet (such as the password
1583 * packet).
1584 *
1585 * Note that because SSH2 sequence-numbers its packets, this can
1586 * NOT be used as an m4-style `defer' allowing packets to be
1587 * constructed in one order and sent in another.
1588 */
1589 static void ssh2_pkt_defer(Ssh ssh)
1590 {
1591 int len = ssh2_pkt_construct(ssh);
1592 if (ssh->deferred_len + len > ssh->deferred_size) {
1593 ssh->deferred_size = ssh->deferred_len + len + 128;
1594 ssh->deferred_send_data = sresize(ssh->deferred_send_data,
1595 ssh->deferred_size,
1596 unsigned char);
1597 }
1598 memcpy(ssh->deferred_send_data + ssh->deferred_len, ssh->pktout.data, len);
1599 ssh->deferred_len += len;
1600 }
1601
1602 /*
1603 * Send the whole deferred data block constructed by
1604 * ssh2_pkt_defer() or SSH1's defer_packet().
1605 */
1606 static void ssh_pkt_defersend(Ssh ssh)
1607 {
1608 int backlog;
1609 backlog = sk_write(ssh->s, (char *)ssh->deferred_send_data,
1610 ssh->deferred_len);
1611 ssh->deferred_len = ssh->deferred_size = 0;
1612 sfree(ssh->deferred_send_data);
1613 ssh->deferred_send_data = NULL;
1614 if (backlog > SSH_MAX_BACKLOG)
1615 ssh_throttle_all(ssh, 1, backlog);
1616 }
1617
1618 #if 0
1619 void bndebug(char *string, Bignum b)
1620 {
1621 unsigned char *p;
1622 int i, len;
1623 p = ssh2_mpint_fmt(b, &len);
1624 debug(("%s", string));
1625 for (i = 0; i < len; i++)
1626 debug((" %02x", p[i]));
1627 debug(("\n"));
1628 sfree(p);
1629 }
1630 #endif
1631
1632 static void sha_mpint(SHA_State * s, Bignum b)
1633 {
1634 unsigned char *p;
1635 int len;
1636 p = ssh2_mpint_fmt(b, &len);
1637 sha_string(s, p, len);
1638 sfree(p);
1639 }
1640
1641 /*
1642 * SSH2 packet decode functions.
1643 */
1644 static unsigned long ssh2_pkt_getuint32(Ssh ssh)
1645 {
1646 unsigned long value;
1647 if (ssh->pktin.length - ssh->pktin.savedpos < 4)
1648 return 0; /* arrgh, no way to decline (FIXME?) */
1649 value = GET_32BIT(ssh->pktin.data + ssh->pktin.savedpos);
1650 ssh->pktin.savedpos += 4;
1651 return value;
1652 }
1653 static int ssh2_pkt_getbool(Ssh ssh)
1654 {
1655 unsigned long value;
1656 if (ssh->pktin.length - ssh->pktin.savedpos < 1)
1657 return 0; /* arrgh, no way to decline (FIXME?) */
1658 value = ssh->pktin.data[ssh->pktin.savedpos] != 0;
1659 ssh->pktin.savedpos++;
1660 return value;
1661 }
1662 static void ssh2_pkt_getstring(Ssh ssh, char **p, int *length)
1663 {
1664 int len;
1665 *p = NULL;
1666 *length = 0;
1667 if (ssh->pktin.length - ssh->pktin.savedpos < 4)
1668 return;
1669 len = GET_32BIT(ssh->pktin.data + ssh->pktin.savedpos);
1670 if (len < 0)
1671 return;
1672 *length = len;
1673 ssh->pktin.savedpos += 4;
1674 if (ssh->pktin.length - ssh->pktin.savedpos < *length)
1675 return;
1676 *p = (char *)(ssh->pktin.data + ssh->pktin.savedpos);
1677 ssh->pktin.savedpos += *length;
1678 }
1679 static Bignum ssh2_pkt_getmp(Ssh ssh)
1680 {
1681 char *p;
1682 int length;
1683 Bignum b;
1684
1685 ssh2_pkt_getstring(ssh, &p, &length);
1686 if (!p)
1687 return NULL;
1688 if (p[0] & 0x80) {
1689 bombout(("internal error: Can't handle negative mpints"));
1690 return NULL;
1691 }
1692 b = bignum_from_bytes((unsigned char *)p, length);
1693 return b;
1694 }
1695
1696 /*
1697 * Helper function to add an SSH2 signature blob to a packet.
1698 * Expects to be shown the public key blob as well as the signature
1699 * blob. Normally works just like ssh2_pkt_addstring, but will
1700 * fiddle with the signature packet if necessary for
1701 * BUG_SSH2_RSA_PADDING.
1702 */
1703 static void ssh2_add_sigblob(Ssh ssh, void *pkblob_v, int pkblob_len,
1704 void *sigblob_v, int sigblob_len)
1705 {
1706 unsigned char *pkblob = (unsigned char *)pkblob_v;
1707 unsigned char *sigblob = (unsigned char *)sigblob_v;
1708
1709 /* dmemdump(pkblob, pkblob_len); */
1710 /* dmemdump(sigblob, sigblob_len); */
1711
1712 /*
1713 * See if this is in fact an ssh-rsa signature and a buggy
1714 * server; otherwise we can just do this the easy way.
1715 */
1716 if ((ssh->remote_bugs & BUG_SSH2_RSA_PADDING) &&
1717 (GET_32BIT(pkblob) == 7 && !memcmp(pkblob+4, "ssh-rsa", 7))) {
1718 int pos, len, siglen;
1719
1720 /*
1721 * Find the byte length of the modulus.
1722 */
1723
1724 pos = 4+7; /* skip over "ssh-rsa" */
1725 pos += 4 + GET_32BIT(pkblob+pos); /* skip over exponent */
1726 len = GET_32BIT(pkblob+pos); /* find length of modulus */
1727 pos += 4; /* find modulus itself */
1728 while (len > 0 && pkblob[pos] == 0)
1729 len--, pos++;
1730 /* debug(("modulus length is %d\n", len)); */
1731
1732 /*
1733 * Now find the signature integer.
1734 */
1735 pos = 4+7; /* skip over "ssh-rsa" */
1736 siglen = GET_32BIT(sigblob+pos);
1737 /* debug(("signature length is %d\n", siglen)); */
1738
1739 if (len != siglen) {
1740 unsigned char newlen[4];
1741 ssh2_pkt_addstring_start(ssh);
1742 ssh2_pkt_addstring_data(ssh, (char *)sigblob, pos);
1743 /* dmemdump(sigblob, pos); */
1744 pos += 4; /* point to start of actual sig */
1745 PUT_32BIT(newlen, len);
1746 ssh2_pkt_addstring_data(ssh, (char *)newlen, 4);
1747 /* dmemdump(newlen, 4); */
1748 newlen[0] = 0;
1749 while (len-- > siglen) {
1750 ssh2_pkt_addstring_data(ssh, (char *)newlen, 1);
1751 /* dmemdump(newlen, 1); */
1752 }
1753 ssh2_pkt_addstring_data(ssh, (char *)(sigblob+pos), siglen);
1754 /* dmemdump(sigblob+pos, siglen); */
1755 return;
1756 }
1757
1758 /* Otherwise fall through and do it the easy way. */
1759 }
1760
1761 ssh2_pkt_addstring_start(ssh);
1762 ssh2_pkt_addstring_data(ssh, (char *)sigblob, sigblob_len);
1763 }
1764
1765 /*
1766 * Examine the remote side's version string and compare it against
1767 * a list of known buggy implementations.
1768 */
1769 static void ssh_detect_bugs(Ssh ssh, char *vstring)
1770 {
1771 char *imp; /* pointer to implementation part */
1772 imp = vstring;
1773 imp += strcspn(imp, "-");
1774 if (*imp) imp++;
1775 imp += strcspn(imp, "-");
1776 if (*imp) imp++;
1777
1778 ssh->remote_bugs = 0;
1779
1780 if (ssh->cfg.sshbug_ignore1 == FORCE_ON ||
1781 (ssh->cfg.sshbug_ignore1 == AUTO &&
1782 (!strcmp(imp, "1.2.18") || !strcmp(imp, "1.2.19") ||
1783 !strcmp(imp, "1.2.20") || !strcmp(imp, "1.2.21") ||
1784 !strcmp(imp, "1.2.22") || !strcmp(imp, "Cisco-1.25") ||
1785 !strcmp(imp, "OSU_1.4alpha3")))) {
1786 /*
1787 * These versions don't support SSH1_MSG_IGNORE, so we have
1788 * to use a different defence against password length
1789 * sniffing.
1790 */
1791 ssh->remote_bugs |= BUG_CHOKES_ON_SSH1_IGNORE;
1792 logevent("We believe remote version has SSH1 ignore bug");
1793 }
1794
1795 if (ssh->cfg.sshbug_plainpw1 == FORCE_ON ||
1796 (ssh->cfg.sshbug_plainpw1 == AUTO &&
1797 (!strcmp(imp, "Cisco-1.25") || !strcmp(imp, "OSU_1.4alpha3")))) {
1798 /*
1799 * These versions need a plain password sent; they can't
1800 * handle having a null and a random length of data after
1801 * the password.
1802 */
1803 ssh->remote_bugs |= BUG_NEEDS_SSH1_PLAIN_PASSWORD;
1804 logevent("We believe remote version needs a plain SSH1 password");
1805 }
1806
1807 if (ssh->cfg.sshbug_rsa1 == FORCE_ON ||
1808 (ssh->cfg.sshbug_rsa1 == AUTO &&
1809 (!strcmp(imp, "Cisco-1.25")))) {
1810 /*
1811 * These versions apparently have no clue whatever about
1812 * RSA authentication and will panic and die if they see
1813 * an AUTH_RSA message.
1814 */
1815 ssh->remote_bugs |= BUG_CHOKES_ON_RSA;
1816 logevent("We believe remote version can't handle RSA authentication");
1817 }
1818
1819 if (ssh->cfg.sshbug_hmac2 == FORCE_ON ||
1820 (ssh->cfg.sshbug_hmac2 == AUTO &&
1821 !wc_match("* VShell", imp) &&
1822 (wc_match("2.1.0*", imp) || wc_match("2.0.*", imp) ||
1823 wc_match("2.2.0*", imp) || wc_match("2.3.0*", imp) ||
1824 wc_match("2.1 *", imp)))) {
1825 /*
1826 * These versions have the HMAC bug.
1827 */
1828 ssh->remote_bugs |= BUG_SSH2_HMAC;
1829 logevent("We believe remote version has SSH2 HMAC bug");
1830 }
1831
1832 if (ssh->cfg.sshbug_derivekey2 == FORCE_ON ||
1833 (ssh->cfg.sshbug_derivekey2 == AUTO &&
1834 !wc_match("* VShell", imp) &&
1835 (wc_match("2.0.0*", imp) || wc_match("2.0.10*", imp) ))) {
1836 /*
1837 * These versions have the key-derivation bug (failing to
1838 * include the literal shared secret in the hashes that
1839 * generate the keys).
1840 */
1841 ssh->remote_bugs |= BUG_SSH2_DERIVEKEY;
1842 logevent("We believe remote version has SSH2 key-derivation bug");
1843 }
1844
1845 if (ssh->cfg.sshbug_rsapad2 == FORCE_ON ||
1846 (ssh->cfg.sshbug_rsapad2 == AUTO &&
1847 (wc_match("OpenSSH_2.[5-9]*", imp) ||
1848 wc_match("OpenSSH_3.[0-2]*", imp)))) {
1849 /*
1850 * These versions have the SSH2 RSA padding bug.
1851 */
1852 ssh->remote_bugs |= BUG_SSH2_RSA_PADDING;
1853 logevent("We believe remote version has SSH2 RSA padding bug");
1854 }
1855
1856 if (ssh->cfg.sshbug_pksessid2 == FORCE_ON ||
1857 (ssh->cfg.sshbug_pksessid2 == AUTO &&
1858 wc_match("OpenSSH_2.[0-2]*", imp))) {
1859 /*
1860 * These versions have the SSH2 session-ID bug in
1861 * public-key authentication.
1862 */
1863 ssh->remote_bugs |= BUG_SSH2_PK_SESSIONID;
1864 logevent("We believe remote version has SSH2 public-key-session-ID bug");
1865 }
1866
1867 if (ssh->cfg.sshbug_dhgex2 == FORCE_ON) {
1868 /*
1869 * User specified the SSH2 DH GEX bug.
1870 */
1871 ssh->remote_bugs |= BUG_SSH2_DH_GEX;
1872 logevent("We believe remote version has SSH2 DH group exchange bug");
1873 }
1874 }
1875
1876 static int do_ssh_init(Ssh ssh, unsigned char c)
1877 {
1878 struct do_ssh_init_state {
1879 int vslen;
1880 char version[10];
1881 char *vstring;
1882 int vstrsize;
1883 int i;
1884 int proto1, proto2;
1885 };
1886 crState(do_ssh_init_state);
1887
1888 crBegin(ssh->do_ssh_init_crstate);
1889
1890 /* Search for the string "SSH-" in the input. */
1891 s->i = 0;
1892 while (1) {
1893 static const int transS[] = { 1, 2, 2, 1 };
1894 static const int transH[] = { 0, 0, 3, 0 };
1895 static const int transminus[] = { 0, 0, 0, -1 };
1896 if (c == 'S')
1897 s->i = transS[s->i];
1898 else if (c == 'H')
1899 s->i = transH[s->i];
1900 else if (c == '-')
1901 s->i = transminus[s->i];
1902 else
1903 s->i = 0;
1904 if (s->i < 0)
1905 break;
1906 crReturn(1); /* get another character */
1907 }
1908
1909 s->vstrsize = 16;
1910 s->vstring = snewn(s->vstrsize, char);
1911 strcpy(s->vstring, "SSH-");
1912 s->vslen = 4;
1913 s->i = 0;
1914 while (1) {
1915 crReturn(1); /* get another char */
1916 if (s->vslen >= s->vstrsize - 1) {
1917 s->vstrsize += 16;
1918 s->vstring = sresize(s->vstring, s->vstrsize, char);
1919 }
1920 s->vstring[s->vslen++] = c;
1921 if (s->i >= 0) {
1922 if (c == '-') {
1923 s->version[s->i] = '\0';
1924 s->i = -1;
1925 } else if (s->i < sizeof(s->version) - 1)
1926 s->version[s->i++] = c;
1927 } else if (c == '\012')
1928 break;
1929 }
1930
1931 ssh->agentfwd_enabled = FALSE;
1932 ssh->rdpkt2_state.incoming_sequence = 0;
1933
1934 s->vstring[s->vslen] = 0;
1935 s->vstring[strcspn(s->vstring, "\r\n")] = '\0';/* remove EOL chars */
1936 {
1937 char *vlog;
1938 vlog = snewn(20 + s->vslen, char);
1939 sprintf(vlog, "Server version: %s", s->vstring);
1940 logevent(vlog);
1941 sfree(vlog);
1942 }
1943 ssh_detect_bugs(ssh, s->vstring);
1944
1945 /*
1946 * Decide which SSH protocol version to support.
1947 */
1948
1949 /* Anything strictly below "2.0" means protocol 1 is supported. */
1950 s->proto1 = ssh_versioncmp(s->version, "2.0") < 0;
1951 /* Anything greater or equal to "1.99" means protocol 2 is supported. */
1952 s->proto2 = ssh_versioncmp(s->version, "1.99") >= 0;
1953
1954 if (ssh->cfg.sshprot == 0 && !s->proto1) {
1955 bombout(("SSH protocol version 1 required by user but not provided by server"));
1956 crStop(0);
1957 }
1958 if (ssh->cfg.sshprot == 3 && !s->proto2) {
1959 bombout(("SSH protocol version 2 required by user but not provided by server"));
1960 crStop(0);
1961 }
1962
1963 if (s->proto2 && (ssh->cfg.sshprot >= 2 || !s->proto1)) {
1964 /*
1965 * Use v2 protocol.
1966 */
1967 char verstring[80], vlog[100];
1968 sprintf(verstring, "SSH-2.0-%s", sshver);
1969 SHA_Init(&ssh->exhashbase);
1970 /*
1971 * Hash our version string and their version string.
1972 */
1973 sha_string(&ssh->exhashbase, verstring, strlen(verstring));
1974 sha_string(&ssh->exhashbase, s->vstring, strcspn(s->vstring, "\r\n"));
1975 sprintf(vlog, "We claim version: %s", verstring);
1976 logevent(vlog);
1977 strcat(verstring, "\012");
1978 logevent("Using SSH protocol version 2");
1979 sk_write(ssh->s, verstring, strlen(verstring));
1980 ssh->protocol = ssh2_protocol;
1981 ssh->version = 2;
1982 ssh->s_rdpkt = ssh2_rdpkt;
1983 } else {
1984 /*
1985 * Use v1 protocol.
1986 */
1987 char verstring[80], vlog[100];
1988 sprintf(verstring, "SSH-%s-%s",
1989 (ssh_versioncmp(s->version, "1.5") <= 0 ? s->version : "1.5"),
1990 sshver);
1991 sprintf(vlog, "We claim version: %s", verstring);
1992 logevent(vlog);
1993 strcat(verstring, "\012");
1994
1995 logevent("Using SSH protocol version 1");
1996 sk_write(ssh->s, verstring, strlen(verstring));
1997 ssh->protocol = ssh1_protocol;
1998 ssh->version = 1;
1999 ssh->s_rdpkt = ssh1_rdpkt;
2000 }
2001 update_specials_menu(ssh->frontend);
2002 ssh->state = SSH_STATE_BEFORE_SIZE;
2003
2004 sfree(s->vstring);
2005
2006 crFinish(0);
2007 }
2008
2009 static void ssh_gotdata(Ssh ssh, unsigned char *data, int datalen)
2010 {
2011 crBegin(ssh->ssh_gotdata_crstate);
2012
2013 /*
2014 * To begin with, feed the characters one by one to the
2015 * protocol initialisation / selection function do_ssh_init().
2016 * When that returns 0, we're done with the initial greeting
2017 * exchange and can move on to packet discipline.
2018 */
2019 while (1) {
2020 int ret; /* need not be kept across crReturn */
2021 if (datalen == 0)
2022 crReturnV; /* more data please */
2023 ret = do_ssh_init(ssh, *data);
2024 data++;
2025 datalen--;
2026 if (ret == 0)
2027 break;
2028 }
2029
2030 /*
2031 * We emerge from that loop when the initial negotiation is
2032 * over and we have selected an s_rdpkt function. Now pass
2033 * everything to s_rdpkt, and then pass the resulting packets
2034 * to the proper protocol handler.
2035 */
2036 if (datalen == 0)
2037 crReturnV;
2038 while (1) {
2039 while (datalen > 0) {
2040 if (ssh->s_rdpkt(ssh, &data, &datalen) == 0) {
2041 if (ssh->state == SSH_STATE_CLOSED) {
2042 return;
2043 }
2044 ssh->protocol(ssh, NULL, 0, 1);
2045 if (ssh->state == SSH_STATE_CLOSED) {
2046 return;
2047 }
2048 }
2049 }
2050 crReturnV;
2051 }
2052 crFinishV;
2053 }
2054
2055 static void ssh_do_close(Ssh ssh)
2056 {
2057 int i;
2058 struct ssh_channel *c;
2059
2060 ssh->state = SSH_STATE_CLOSED;
2061 if (ssh->s) {
2062 sk_close(ssh->s);
2063 ssh->s = NULL;
2064 }
2065 /*
2066 * Now we must shut down any port and X forwardings going
2067 * through this connection.
2068 */
2069 if (ssh->channels) {
2070 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
2071 switch (c->type) {
2072 case CHAN_X11:
2073 x11_close(c->u.x11.s);
2074 break;
2075 case CHAN_SOCKDATA:
2076 pfd_close(c->u.pfd.s);
2077 break;
2078 }
2079 del234(ssh->channels, c);
2080 if (ssh->version == 2)
2081 bufchain_clear(&c->v.v2.outbuffer);
2082 sfree(c);
2083 }
2084 }
2085 }
2086
2087 static int ssh_closing(Plug plug, const char *error_msg, int error_code,
2088 int calling_back)
2089 {
2090 Ssh ssh = (Ssh) plug;
2091 ssh_do_close(ssh);
2092 if (error_msg) {
2093 /* A socket error has occurred. */
2094 logevent(error_msg);
2095 connection_fatal(ssh->frontend, "%s", error_msg);
2096 } else {
2097 /* Otherwise, the remote side closed the connection normally. */
2098 }
2099 return 0;
2100 }
2101
2102 static int ssh_receive(Plug plug, int urgent, char *data, int len)
2103 {
2104 Ssh ssh = (Ssh) plug;
2105 ssh_gotdata(ssh, (unsigned char *)data, len);
2106 if (ssh->state == SSH_STATE_CLOSED) {
2107 ssh_do_close(ssh);
2108 return 0;
2109 }
2110 return 1;
2111 }
2112
2113 static void ssh_sent(Plug plug, int bufsize)
2114 {
2115 Ssh ssh = (Ssh) plug;
2116 /*
2117 * If the send backlog on the SSH socket itself clears, we
2118 * should unthrottle the whole world if it was throttled.
2119 */
2120 if (bufsize < SSH_MAX_BACKLOG)
2121 ssh_throttle_all(ssh, 0, bufsize);
2122 }
2123
2124 /*
2125 * Connect to specified host and port.
2126 * Returns an error message, or NULL on success.
2127 * Also places the canonical host name into `realhost'. It must be
2128 * freed by the caller.
2129 */
2130 static const char *connect_to_host(Ssh ssh, char *host, int port,
2131 char **realhost, int nodelay, int keepalive)
2132 {
2133 static const struct plug_function_table fn_table = {
2134 ssh_closing,
2135 ssh_receive,
2136 ssh_sent,
2137 NULL
2138 };
2139
2140 SockAddr addr;
2141 const char *err;
2142
2143 ssh->savedhost = snewn(1 + strlen(host), char);
2144 if (!ssh->savedhost)
2145 fatalbox("Out of memory");
2146 strcpy(ssh->savedhost, host);
2147
2148 if (port < 0)
2149 port = 22; /* default ssh port */
2150 ssh->savedport = port;
2151
2152 /*
2153 * Try to find host.
2154 */
2155 logeventf(ssh, "Looking up host \"%s\"", host);
2156 addr = name_lookup(host, port, realhost, &ssh->cfg);
2157 if ((err = sk_addr_error(addr)) != NULL) {
2158 sk_addr_free(addr);
2159 return err;
2160 }
2161
2162 /*
2163 * Open socket.
2164 */
2165 {
2166 char addrbuf[100];
2167 sk_getaddr(addr, addrbuf, 100);
2168 logeventf(ssh, "Connecting to %s port %d", addrbuf, port);
2169 }
2170 ssh->fn = &fn_table;
2171 ssh->s = new_connection(addr, *realhost, port,
2172 0, 1, nodelay, keepalive, (Plug) ssh, &ssh->cfg);
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 if (servkey.modulus) {
2540 sfree(servkey.modulus);
2541 servkey.modulus = NULL;
2542 }
2543 if (servkey.exponent) {
2544 sfree(servkey.exponent);
2545 servkey.exponent = NULL;
2546 }
2547 if (hostkey.modulus) {
2548 sfree(hostkey.modulus);
2549 hostkey.modulus = NULL;
2550 }
2551 if (hostkey.exponent) {
2552 sfree(hostkey.exponent);
2553 hostkey.exponent = NULL;
2554 }
2555 crWaitUntil(ispkt);
2556
2557 if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
2558 bombout(("Encryption not successfully enabled"));
2559 crStop(0);
2560 }
2561
2562 logevent("Successfully started encryption");
2563
2564 fflush(stdout);
2565 {
2566 if ((flags & FLAG_INTERACTIVE) && !*ssh->cfg.username) {
2567 if (ssh_get_line && !ssh_getline_pw_only) {
2568 if (!ssh_get_line("login as: ",
2569 s->username, sizeof(s->username), FALSE)) {
2570 /*
2571 * get_line failed to get a username.
2572 * Terminate.
2573 */
2574 logevent("No username provided. Abandoning session.");
2575 ssh_closing((Plug)ssh, NULL, 0, 0);
2576 crStop(1);
2577 }
2578 } else {
2579 int ret; /* need not be kept over crReturn */
2580 c_write_str(ssh, "login as: ");
2581 ssh->send_ok = 1;
2582
2583 setup_userpass_input(ssh, s->username, sizeof(s->username), 1);
2584 do {
2585 crWaitUntil(!ispkt);
2586 ret = process_userpass_input(ssh, in, inlen);
2587 } while (ret == 0);
2588 if (ret < 0)
2589 cleanup_exit(0);
2590 c_write_str(ssh, "\r\n");
2591 }
2592 } else {
2593 strncpy(s->username, ssh->cfg.username, sizeof(s->username));
2594 s->username[sizeof(s->username)-1] = '\0';
2595 }
2596
2597 send_packet(ssh, SSH1_CMSG_USER, PKT_STR, s->username, PKT_END);
2598 {
2599 char userlog[22 + sizeof(s->username)];
2600 sprintf(userlog, "Sent username \"%s\"", s->username);
2601 logevent(userlog);
2602 if (flags & FLAG_INTERACTIVE &&
2603 (!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) {
2604 strcat(userlog, "\r\n");
2605 c_write_str(ssh, userlog);
2606 }
2607 }
2608 }
2609
2610 crWaitUntil(ispkt);
2611
2612 if ((ssh->remote_bugs & BUG_CHOKES_ON_RSA)) {
2613 /* We must not attempt PK auth. Pretend we've already tried it. */
2614 s->tried_publickey = s->tried_agent = 1;
2615 } else {
2616 s->tried_publickey = s->tried_agent = 0;
2617 }
2618 s->tis_auth_refused = s->ccard_auth_refused = 0;
2619 /* Load the public half of ssh->cfg.keyfile so we notice if it's in Pageant */
2620 if (!filename_is_null(ssh->cfg.keyfile)) {
2621 if (!rsakey_pubblob(&ssh->cfg.keyfile,
2622 &s->publickey_blob, &s->publickey_bloblen, NULL))
2623 s->publickey_blob = NULL;
2624 } else
2625 s->publickey_blob = NULL;
2626
2627 while (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2628 s->pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
2629
2630 if (agent_exists() && !s->tried_agent) {
2631 /*
2632 * Attempt RSA authentication using Pageant.
2633 */
2634 void *r;
2635
2636 s->authed = FALSE;
2637 s->tried_agent = 1;
2638 logevent("Pageant is running. Requesting keys.");
2639
2640 /* Request the keys held by the agent. */
2641 PUT_32BIT(s->request, 1);
2642 s->request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES;
2643 if (!agent_query(s->request, 5, &r, &s->responselen,
2644 ssh_agent_callback, ssh)) {
2645 do {
2646 crReturn(0);
2647 if (ispkt) {
2648 bombout(("Unexpected data from server while waiting"
2649 " for agent response"));
2650 crStop(0);
2651 }
2652 } while (ispkt || inlen > 0);
2653 r = ssh->agent_response;
2654 s->responselen = ssh->agent_response_len;
2655 }
2656 s->response = (unsigned char *) r;
2657 if (s->response && s->responselen >= 5 &&
2658 s->response[4] == SSH1_AGENT_RSA_IDENTITIES_ANSWER) {
2659 s->p = s->response + 5;
2660 s->nkeys = GET_32BIT(s->p);
2661 s->p += 4;
2662 {
2663 char buf[64];
2664 sprintf(buf, "Pageant has %d SSH1 keys", s->nkeys);
2665 logevent(buf);
2666 }
2667 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
2668 {
2669 char buf[64];
2670 sprintf(buf, "Trying Pageant key #%d", s->keyi);
2671 logevent(buf);
2672 }
2673 if (s->publickey_blob &&
2674 !memcmp(s->p, s->publickey_blob,
2675 s->publickey_bloblen)) {
2676 logevent("This key matches configured key file");
2677 s->tried_publickey = 1;
2678 }
2679 s->p += 4;
2680 s->p += ssh1_read_bignum(s->p, &s->key.exponent);
2681 s->p += ssh1_read_bignum(s->p, &s->key.modulus);
2682 s->commentlen = GET_32BIT(s->p);
2683 s->p += 4;
2684 s->commentp = (char *)s->p;
2685 s->p += s->commentlen;
2686 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
2687 PKT_BIGNUM, s->key.modulus, PKT_END);
2688 crWaitUntil(ispkt);
2689 if (ssh->pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
2690 logevent("Key refused");
2691 continue;
2692 }
2693 logevent("Received RSA challenge");
2694 ssh1_read_bignum(ssh->pktin.body, &s->challenge);
2695 {
2696 char *agentreq, *q, *ret;
2697 void *vret;
2698 int len, retlen;
2699 len = 1 + 4; /* message type, bit count */
2700 len += ssh1_bignum_length(s->key.exponent);
2701 len += ssh1_bignum_length(s->key.modulus);
2702 len += ssh1_bignum_length(s->challenge);
2703 len += 16; /* session id */
2704 len += 4; /* response format */
2705 agentreq = snewn(4 + len, char);
2706 PUT_32BIT(agentreq, len);
2707 q = agentreq + 4;
2708 *q++ = SSH1_AGENTC_RSA_CHALLENGE;
2709 PUT_32BIT(q, bignum_bitcount(s->key.modulus));
2710 q += 4;
2711 q += ssh1_write_bignum(q, s->key.exponent);
2712 q += ssh1_write_bignum(q, s->key.modulus);
2713 q += ssh1_write_bignum(q, s->challenge);
2714 memcpy(q, s->session_id, 16);
2715 q += 16;
2716 PUT_32BIT(q, 1); /* response format */
2717 if (!agent_query(agentreq, len + 4, &vret, &retlen,
2718 ssh_agent_callback, ssh)) {
2719 sfree(agentreq);
2720 do {
2721 crReturn(0);
2722 if (ispkt) {
2723 bombout(("Unexpected data from server"
2724 " while waiting for agent"
2725 " response"));
2726 crStop(0);
2727 }
2728 } while (ispkt || inlen > 0);
2729 vret = ssh->agent_response;
2730 retlen = ssh->agent_response_len;
2731 } else
2732 sfree(agentreq);
2733 ret = vret;
2734 if (ret) {
2735 if (ret[4] == SSH1_AGENT_RSA_RESPONSE) {
2736 logevent("Sending Pageant's response");
2737 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
2738 PKT_DATA, ret + 5, 16,
2739 PKT_END);
2740 sfree(ret);
2741 crWaitUntil(ispkt);
2742 if (ssh->pktin.type == SSH1_SMSG_SUCCESS) {
2743 logevent
2744 ("Pageant's response accepted");
2745 if (flags & FLAG_VERBOSE) {
2746 c_write_str(ssh, "Authenticated using"
2747 " RSA key \"");
2748 c_write(ssh, s->commentp,
2749 s->commentlen);
2750 c_write_str(ssh, "\" from agent\r\n");
2751 }
2752 s->authed = TRUE;
2753 } else
2754 logevent
2755 ("Pageant's response not accepted");
2756 } else {
2757 logevent
2758 ("Pageant failed to answer challenge");
2759 sfree(ret);
2760 }
2761 } else {
2762 logevent("No reply received from Pageant");
2763 }
2764 }
2765 freebn(s->key.exponent);
2766 freebn(s->key.modulus);
2767 freebn(s->challenge);
2768 if (s->authed)
2769 break;
2770 }
2771 sfree(s->response);
2772 }
2773 if (s->authed)
2774 break;
2775 }
2776 if (!filename_is_null(ssh->cfg.keyfile) && !s->tried_publickey)
2777 s->pwpkt_type = SSH1_CMSG_AUTH_RSA;
2778
2779 if (ssh->cfg.try_tis_auth &&
2780 (s->supported_auths_mask & (1 << SSH1_AUTH_TIS)) &&
2781 !s->tis_auth_refused) {
2782 s->pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
2783 logevent("Requested TIS authentication");
2784 send_packet(ssh, SSH1_CMSG_AUTH_TIS, PKT_END);
2785 crWaitUntil(ispkt);
2786 if (ssh->pktin.type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
2787 logevent("TIS authentication declined");
2788 if (flags & FLAG_INTERACTIVE)
2789 c_write_str(ssh, "TIS authentication refused.\r\n");
2790 s->tis_auth_refused = 1;
2791 continue;
2792 } else {
2793 int challengelen = GET_32BIT(ssh->pktin.body);
2794 logevent("Received TIS challenge");
2795 if (challengelen > sizeof(s->prompt) - 1)
2796 challengelen = sizeof(s->prompt) - 1;/* prevent overrun */
2797 memcpy(s->prompt, ssh->pktin.body + 4, challengelen);
2798 /* Prompt heuristic comes from OpenSSH */
2799 strncpy(s->prompt + challengelen,
2800 memchr(s->prompt, '\n', challengelen) ?
2801 "": "\r\nResponse: ",
2802 (sizeof s->prompt) - challengelen);
2803 s->prompt[(sizeof s->prompt) - 1] = '\0';
2804 }
2805 }
2806 if (ssh->cfg.try_tis_auth &&
2807 (s->supported_auths_mask & (1 << SSH1_AUTH_CCARD)) &&
2808 !s->ccard_auth_refused) {
2809 s->pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE;
2810 logevent("Requested CryptoCard authentication");
2811 send_packet(ssh, SSH1_CMSG_AUTH_CCARD, PKT_END);
2812 crWaitUntil(ispkt);
2813 if (ssh->pktin.type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
2814 logevent("CryptoCard authentication declined");
2815 c_write_str(ssh, "CryptoCard authentication refused.\r\n");
2816 s->ccard_auth_refused = 1;
2817 continue;
2818 } else {
2819 int challengelen = GET_32BIT(ssh->pktin.body);
2820 logevent("Received CryptoCard challenge");
2821 if (challengelen > sizeof(s->prompt) - 1)
2822 challengelen = sizeof(s->prompt) - 1;/* prevent overrun */
2823 memcpy(s->prompt, ssh->pktin.body + 4, challengelen);
2824 strncpy(s->prompt + challengelen,
2825 memchr(s->prompt, '\n', challengelen) ?
2826 "" : "\r\nResponse: ",
2827 sizeof(s->prompt) - challengelen);
2828 s->prompt[sizeof(s->prompt) - 1] = '\0';
2829 }
2830 }
2831 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
2832 sprintf(s->prompt, "%.90s@%.90s's password: ",
2833 s->username, ssh->savedhost);
2834 }
2835 if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) {
2836 char *comment = NULL;
2837 int type;
2838 char msgbuf[256];
2839 if (flags & FLAG_VERBOSE)
2840 c_write_str(ssh, "Trying public key authentication.\r\n");
2841 logeventf(ssh, "Trying public key \"%s\"",
2842 filename_to_str(&ssh->cfg.keyfile));
2843 type = key_type(&ssh->cfg.keyfile);
2844 if (type != SSH_KEYTYPE_SSH1) {
2845 sprintf(msgbuf, "Key is of wrong type (%s)",
2846 key_type_to_str(type));
2847 logevent(msgbuf);
2848 c_write_str(ssh, msgbuf);
2849 c_write_str(ssh, "\r\n");
2850 s->tried_publickey = 1;
2851 continue;
2852 }
2853 if (!rsakey_encrypted(&ssh->cfg.keyfile, &comment)) {
2854 if (flags & FLAG_VERBOSE)
2855 c_write_str(ssh, "No passphrase required.\r\n");
2856 goto tryauth;
2857 }
2858 sprintf(s->prompt, "Passphrase for key \"%.100s\": ", comment);
2859 sfree(comment);
2860 }
2861
2862 /*
2863 * Show password prompt, having first obtained it via a TIS
2864 * or CryptoCard exchange if we're doing TIS or CryptoCard
2865 * authentication.
2866 */
2867 if (ssh_get_line) {
2868 if (!ssh_get_line(s->prompt, s->password,
2869 sizeof(s->password), TRUE)) {
2870 /*
2871 * get_line failed to get a password (for example
2872 * because one was supplied on the command line
2873 * which has already failed to work). Terminate.
2874 */
2875 send_packet(ssh, SSH1_MSG_DISCONNECT,
2876 PKT_STR, "No more passwords available to try",
2877 PKT_END);
2878 logevent("Unable to authenticate");
2879 connection_fatal(ssh->frontend, "Unable to authenticate");
2880 ssh_closing((Plug)ssh, NULL, 0, 0);
2881 crStop(1);
2882 }
2883 } else {
2884 /* Prompt may have come from server. We've munged it a bit, so
2885 * we know it to be zero-terminated at least once. */
2886 int ret; /* need not be saved over crReturn */
2887 c_write_untrusted(ssh, s->prompt, strlen(s->prompt));
2888 s->pos = 0;
2889
2890 setup_userpass_input(ssh, s->password, sizeof(s->password), 0);
2891 do {
2892 crWaitUntil(!ispkt);
2893 ret = process_userpass_input(ssh, in, inlen);
2894 } while (ret == 0);
2895 if (ret < 0)
2896 cleanup_exit(0);
2897 c_write_str(ssh, "\r\n");
2898 }
2899
2900 tryauth:
2901 if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) {
2902 /*
2903 * Try public key authentication with the specified
2904 * key file.
2905 */
2906 s->tried_publickey = 1;
2907
2908 {
2909 const char *error = NULL;
2910 int ret = loadrsakey(&ssh->cfg.keyfile, &s->key, s->password,
2911 &error);
2912 if (ret == 0) {
2913 c_write_str(ssh, "Couldn't load private key from ");
2914 c_write_str(ssh, filename_to_str(&ssh->cfg.keyfile));
2915 c_write_str(ssh, " (");
2916 c_write_str(ssh, error);
2917 c_write_str(ssh, ").\r\n");
2918 continue; /* go and try password */
2919 }
2920 if (ret == -1) {
2921 c_write_str(ssh, "Wrong passphrase.\r\n");
2922 s->tried_publickey = 0;
2923 continue; /* try again */
2924 }
2925 }
2926
2927 /*
2928 * Send a public key attempt.
2929 */
2930 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
2931 PKT_BIGNUM, s->key.modulus, PKT_END);
2932
2933 crWaitUntil(ispkt);
2934 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2935 c_write_str(ssh, "Server refused our public key.\r\n");
2936 continue; /* go and try password */
2937 }
2938 if (ssh->pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
2939 bombout(("Bizarre response to offer of public key"));
2940 crStop(0);
2941 }
2942
2943 {
2944 int i;
2945 unsigned char buffer[32];
2946 Bignum challenge, response;
2947
2948 ssh1_read_bignum(ssh->pktin.body, &challenge);
2949 response = rsadecrypt(challenge, &s->key);
2950 freebn(s->key.private_exponent);/* burn the evidence */
2951
2952 for (i = 0; i < 32; i++) {
2953 buffer[i] = bignum_byte(response, 31 - i);
2954 }
2955
2956 MD5Init(&md5c);
2957 MD5Update(&md5c, buffer, 32);
2958 MD5Update(&md5c, s->session_id, 16);
2959 MD5Final(buffer, &md5c);
2960
2961 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
2962 PKT_DATA, buffer, 16, PKT_END);
2963
2964 freebn(challenge);
2965 freebn(response);
2966 }
2967
2968 crWaitUntil(ispkt);
2969 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2970 if (flags & FLAG_VERBOSE)
2971 c_write_str(ssh, "Failed to authenticate with"
2972 " our public key.\r\n");
2973 continue; /* go and try password */
2974 } else if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
2975 bombout(("Bizarre response to RSA authentication response"));
2976 crStop(0);
2977 }
2978
2979 break; /* we're through! */
2980 } else {
2981 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
2982 /*
2983 * Defence against traffic analysis: we send a
2984 * whole bunch of packets containing strings of
2985 * different lengths. One of these strings is the
2986 * password, in a SSH1_CMSG_AUTH_PASSWORD packet.
2987 * The others are all random data in
2988 * SSH1_MSG_IGNORE packets. This way a passive
2989 * listener can't tell which is the password, and
2990 * hence can't deduce the password length.
2991 *
2992 * Anybody with a password length greater than 16
2993 * bytes is going to have enough entropy in their
2994 * password that a listener won't find it _that_
2995 * much help to know how long it is. So what we'll
2996 * do is:
2997 *
2998 * - if password length < 16, we send 15 packets
2999 * containing string lengths 1 through 15
3000 *
3001 * - otherwise, we let N be the nearest multiple
3002 * of 8 below the password length, and send 8
3003 * packets containing string lengths N through
3004 * N+7. This won't obscure the order of
3005 * magnitude of the password length, but it will
3006 * introduce a bit of extra uncertainty.
3007 *
3008 * A few servers (the old 1.2.18 through 1.2.22)
3009 * can't deal with SSH1_MSG_IGNORE. For these
3010 * servers, we need an alternative defence. We make
3011 * use of the fact that the password is interpreted
3012 * as a C string: so we can append a NUL, then some
3013 * random data.
3014 *
3015 * One server (a Cisco one) can deal with neither
3016 * SSH1_MSG_IGNORE _nor_ a padded password string.
3017 * For this server we are left with no defences
3018 * against password length sniffing.
3019 */
3020 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE)) {
3021 /*
3022 * The server can deal with SSH1_MSG_IGNORE, so
3023 * we can use the primary defence.
3024 */
3025 int bottom, top, pwlen, i;
3026 char *randomstr;
3027
3028 pwlen = strlen(s->password);
3029 if (pwlen < 16) {
3030 bottom = 0; /* zero length passwords are OK! :-) */
3031 top = 15;
3032 } else {
3033 bottom = pwlen & ~7;
3034 top = bottom + 7;
3035 }
3036
3037 assert(pwlen >= bottom && pwlen <= top);
3038
3039 randomstr = snewn(top + 1, char);
3040
3041 for (i = bottom; i <= top; i++) {
3042 if (i == pwlen)
3043 defer_packet(ssh, s->pwpkt_type,
3044 PKT_STR, s->password, PKT_END);
3045 else {
3046 for (j = 0; j < i; j++) {
3047 do {
3048 randomstr[j] = random_byte();
3049 } while (randomstr[j] == '\0');
3050 }
3051 randomstr[i] = '\0';
3052 defer_packet(ssh, SSH1_MSG_IGNORE,
3053 PKT_STR, randomstr, PKT_END);
3054 }
3055 }
3056 logevent("Sending password with camouflage packets");
3057 ssh_pkt_defersend(ssh);
3058 sfree(randomstr);
3059 }
3060 else if (!(ssh->remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) {
3061 /*
3062 * The server can't deal with SSH1_MSG_IGNORE
3063 * but can deal with padded passwords, so we
3064 * can use the secondary defence.
3065 */
3066 char string[64];
3067 char *ss;
3068 int len;
3069
3070 len = strlen(s->password);
3071 if (len < sizeof(string)) {
3072 ss = string;
3073 strcpy(string, s->password);
3074 len++; /* cover the zero byte */
3075 while (len < sizeof(string)) {
3076 string[len++] = (char) random_byte();
3077 }
3078 } else {
3079 ss = s->password;
3080 }
3081 logevent("Sending length-padded password");
3082 send_packet(ssh, s->pwpkt_type, PKT_INT, len,
3083 PKT_DATA, ss, len, PKT_END);
3084 } else {
3085 /*
3086 * The server has _both_
3087 * BUG_CHOKES_ON_SSH1_IGNORE and
3088 * BUG_NEEDS_SSH1_PLAIN_PASSWORD. There is
3089 * therefore nothing we can do.
3090 */
3091 int len;
3092 len = strlen(s->password);
3093 logevent("Sending unpadded password");
3094 send_packet(ssh, s->pwpkt_type, PKT_INT, len,
3095 PKT_DATA, s->password, len, PKT_END);
3096 }
3097 } else {
3098 send_packet(ssh, s->pwpkt_type, PKT_STR, s->password, PKT_END);
3099 }
3100 }
3101 logevent("Sent password");
3102 memset(s->password, 0, strlen(s->password));
3103 crWaitUntil(ispkt);
3104 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3105 if (flags & FLAG_VERBOSE)
3106 c_write_str(ssh, "Access denied\r\n");
3107 logevent("Authentication refused");
3108 } else if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
3109 bombout(("Strange packet received, type %d", ssh->pktin.type));
3110 crStop(0);
3111 }
3112 }
3113
3114 logevent("Authentication successful");
3115
3116 crFinish(1);
3117 }
3118
3119 void sshfwd_close(struct ssh_channel *c)
3120 {
3121 Ssh ssh = c->ssh;
3122
3123 if (ssh->state != SSH_STATE_SESSION) {
3124 assert(ssh->state == SSH_STATE_CLOSED);
3125 return;
3126 }
3127
3128 if (c && !c->closes) {
3129 /*
3130 * If the channel's remoteid is -1, we have sent
3131 * CHANNEL_OPEN for this channel, but it hasn't even been
3132 * acknowledged by the server. So we must set a close flag
3133 * on it now, and then when the server acks the channel
3134 * open, we can close it then.
3135 */
3136 if (((int)c->remoteid) != -1) {
3137 if (ssh->version == 1) {
3138 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid,
3139 PKT_END);
3140 } else {
3141 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
3142 ssh2_pkt_adduint32(ssh, c->remoteid);
3143 ssh2_pkt_send(ssh);
3144 }
3145 }
3146 c->closes = 1; /* sent MSG_CLOSE */
3147 if (c->type == CHAN_X11) {
3148 c->u.x11.s = NULL;
3149 logevent("Forwarded X11 connection terminated");
3150 } else if (c->type == CHAN_SOCKDATA ||
3151 c->type == CHAN_SOCKDATA_DORMANT) {
3152 c->u.pfd.s = NULL;
3153 logevent("Forwarded port closed");
3154 }
3155 }
3156 }
3157
3158 int sshfwd_write(struct ssh_channel *c, char *buf, int len)
3159 {
3160 Ssh ssh = c->ssh;
3161
3162 if (ssh->state != SSH_STATE_SESSION) {
3163 assert(ssh->state == SSH_STATE_CLOSED);
3164 return 0;
3165 }
3166
3167 if (ssh->version == 1) {
3168 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
3169 PKT_INT, c->remoteid,
3170 PKT_INT, len, PKT_DATA, buf, len, PKT_END);
3171 /*
3172 * In SSH1 we can return 0 here - implying that forwarded
3173 * connections are never individually throttled - because
3174 * the only circumstance that can cause throttling will be
3175 * the whole SSH connection backing up, in which case
3176 * _everything_ will be throttled as a whole.
3177 */
3178 return 0;
3179 } else {
3180 ssh2_add_channel_data(c, buf, len);
3181 return ssh2_try_send(c);
3182 }
3183 }
3184
3185 void sshfwd_unthrottle(struct ssh_channel *c, int bufsize)
3186 {
3187 Ssh ssh = c->ssh;
3188
3189 if (ssh->state != SSH_STATE_SESSION) {
3190 assert(ssh->state == SSH_STATE_CLOSED);
3191 return;
3192 }
3193
3194 if (ssh->version == 1) {
3195 if (c->v.v1.throttling && bufsize < SSH1_BUFFER_LIMIT) {
3196 c->v.v1.throttling = 0;
3197 ssh1_throttle(ssh, -1);
3198 }
3199 } else {
3200 ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
3201 }
3202 }
3203
3204 static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
3205 {
3206 crBegin(ssh->ssh1_protocol_crstate);
3207
3208 random_init();
3209
3210 while (!do_ssh1_login(ssh, in, inlen, ispkt)) {
3211 crReturnV;
3212 }
3213 if (ssh->state == SSH_STATE_CLOSED)
3214 crReturnV;
3215
3216 if (ssh->cfg.agentfwd && agent_exists()) {
3217 logevent("Requesting agent forwarding");
3218 send_packet(ssh, SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END);
3219 do {
3220 crReturnV;
3221 } while (!ispkt);
3222 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3223 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3224 bombout(("Protocol confusion"));
3225 crStopV;
3226 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3227 logevent("Agent forwarding refused");
3228 } else {
3229 logevent("Agent forwarding enabled");
3230 ssh->agentfwd_enabled = TRUE;
3231 }
3232 }
3233
3234 if (ssh->cfg.x11_forward) {
3235 char proto[20], data[64];
3236 logevent("Requesting X11 forwarding");
3237 ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
3238 data, sizeof(data), ssh->cfg.x11_auth);
3239 x11_get_real_auth(ssh->x11auth, ssh->cfg.x11_display);
3240 if (ssh->v1_local_protoflags & SSH1_PROTOFLAG_SCREEN_NUMBER) {
3241 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
3242 PKT_STR, proto, PKT_STR, data,
3243 PKT_INT, x11_get_screen_number(ssh->cfg.x11_display),
3244 PKT_END);
3245 } else {
3246 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
3247 PKT_STR, proto, PKT_STR, data, PKT_END);
3248 }
3249 do {
3250 crReturnV;
3251 } while (!ispkt);
3252 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3253 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3254 bombout(("Protocol confusion"));
3255 crStopV;
3256 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3257 logevent("X11 forwarding refused");
3258 } else {
3259 logevent("X11 forwarding enabled");
3260 ssh->X11_fwd_enabled = TRUE;
3261 }
3262 }
3263
3264 {
3265 char type;
3266 int n;
3267 int sport,dport,sserv,dserv;
3268 char sports[256], dports[256], saddr[256], host[256];
3269
3270 ssh->rportfwds = newtree234(ssh_rportcmp_ssh1);
3271 /* Add port forwardings. */
3272 ssh->portfwd_strptr = ssh->cfg.portfwd;
3273 while (*ssh->portfwd_strptr) {
3274 type = *ssh->portfwd_strptr++;
3275 saddr[0] = '\0';
3276 n = 0;
3277 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != '\t') {
3278 if (*ssh->portfwd_strptr == ':') {
3279 /*
3280 * We've seen a colon in the middle of the
3281 * source port number. This means that
3282 * everything we've seen until now is the
3283 * source _address_, so we'll move it into
3284 * saddr and start sports from the beginning
3285 * again.
3286 */
3287 ssh->portfwd_strptr++;
3288 sports[n] = '\0';
3289 strcpy(saddr, sports);
3290 n = 0;
3291 }
3292 if (n < 255) sports[n++] = *ssh->portfwd_strptr++;
3293 }
3294 sports[n] = 0;
3295 if (type != 'D') {
3296 if (*ssh->portfwd_strptr == '\t')
3297 ssh->portfwd_strptr++;
3298 n = 0;
3299 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':') {
3300 if (n < 255) host[n++] = *ssh->portfwd_strptr++;
3301 }
3302 host[n] = 0;
3303 if (*ssh->portfwd_strptr == ':')
3304 ssh->portfwd_strptr++;
3305 n = 0;
3306 while (*ssh->portfwd_strptr) {
3307 if (n < 255) dports[n++] = *ssh->portfwd_strptr++;
3308 }
3309 dports[n] = 0;
3310 ssh->portfwd_strptr++;
3311 dport = atoi(dports);
3312 dserv = 0;
3313 if (dport == 0) {
3314 dserv = 1;
3315 dport = net_service_lookup(dports);
3316 if (!dport) {
3317 logeventf(ssh, "Service lookup failed for"
3318 " destination port \"%s\"", dports);
3319 }
3320 }
3321 } else {
3322 while (*ssh->portfwd_strptr) ssh->portfwd_strptr++;
3323 dport = dserv = -1;
3324 ssh->portfwd_strptr++; /* eat the NUL and move to next one */
3325 }
3326 sport = atoi(sports);
3327 sserv = 0;
3328 if (sport == 0) {
3329 sserv = 1;
3330 sport = net_service_lookup(sports);
3331 if (!sport) {
3332 logeventf(ssh, "Service lookup failed for source"
3333 " port \"%s\"", sports);
3334 }
3335 }
3336 if (sport && dport) {
3337 if (type == 'L') {
3338 pfd_addforward(host, dport, *saddr ? saddr : NULL,
3339 sport, ssh, &ssh->cfg);
3340 logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
3341 " forwarding to %s:%.*s%.*s%d%.*s",
3342 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
3343 (int)(*saddr?1:0), ":",
3344 (int)(sserv ? strlen(sports) : 0), sports,
3345 sserv, "(", sport, sserv, ")",
3346 host,
3347 (int)(dserv ? strlen(dports) : 0), dports,
3348 dserv, "(", dport, dserv, ")");
3349 } else if (type == 'D') {
3350 pfd_addforward(NULL, -1, *saddr ? saddr : NULL,
3351 sport, ssh, &ssh->cfg);
3352 logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
3353 " doing SOCKS dynamic forwarding",
3354 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
3355 (int)(*saddr?1:0), ":",
3356 (int)(sserv ? strlen(sports) : 0), sports,
3357 sserv, "(", sport, sserv, ")");
3358 } else {
3359 struct ssh_rportfwd *pf;
3360 pf = snew(struct ssh_rportfwd);
3361 strcpy(pf->dhost, host);
3362 pf->dport = dport;
3363 if (saddr) {
3364 logeventf(ssh,
3365 "SSH1 cannot handle source address spec \"%s:%d\"; ignoring",
3366 saddr, sport);
3367 }
3368 if (add234(ssh->rportfwds, pf) != pf) {
3369 logeventf(ssh,
3370 "Duplicate remote port forwarding to %s:%d",
3371 host, dport);
3372 sfree(pf);
3373 } else {
3374 logeventf(ssh, "Requesting remote port %.*s%.*s%d%.*s"
3375 " forward to %s:%.*s%.*s%d%.*s",
3376 (int)(sserv ? strlen(sports) : 0), sports,
3377 sserv, "(", sport, sserv, ")",
3378 host,
3379 (int)(dserv ? strlen(dports) : 0), dports,
3380 dserv, "(", dport, dserv, ")");
3381 send_packet(ssh, SSH1_CMSG_PORT_FORWARD_REQUEST,
3382 PKT_INT, sport,
3383 PKT_STR, host,
3384 PKT_INT, dport,
3385 PKT_END);
3386 do {
3387 crReturnV;
3388 } while (!ispkt);
3389 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3390 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3391 bombout(("Protocol confusion"));
3392 crStopV;
3393 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3394 c_write_str(ssh, "Server refused port"
3395 " forwarding\r\n");
3396 }
3397 logevent("Remote port forwarding enabled");
3398 }
3399 }
3400 }
3401 }
3402 }
3403
3404 if (!ssh->cfg.nopty) {
3405 /* Unpick the terminal-speed string. */
3406 /* XXX perhaps we should allow no speeds to be sent. */
3407 ssh->ospeed = 38400; ssh->ispeed = 38400; /* last-resort defaults */
3408 sscanf(ssh->cfg.termspeed, "%d,%d", &ssh->ospeed, &ssh->ispeed);
3409 /* Send the pty request. */
3410 send_packet(ssh, SSH1_CMSG_REQUEST_PTY,
3411 PKT_STR, ssh->cfg.termtype,
3412 PKT_INT, ssh->term_height,
3413 PKT_INT, ssh->term_width,
3414 PKT_INT, 0, PKT_INT, 0, /* width,height in pixels */
3415 PKT_CHAR, 192, PKT_INT, ssh->ispeed, /* TTY_OP_ISPEED */
3416 PKT_CHAR, 193, PKT_INT, ssh->ospeed, /* TTY_OP_OSPEED */
3417 PKT_CHAR, 0, PKT_END);
3418 ssh->state = SSH_STATE_INTERMED;
3419 do {
3420 crReturnV;
3421 } while (!ispkt);
3422 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3423 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3424 bombout(("Protocol confusion"));
3425 crStopV;
3426 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3427 c_write_str(ssh, "Server refused to allocate pty\r\n");
3428 ssh->editing = ssh->echoing = 1;
3429 }
3430 logeventf(ssh, "Allocated pty (ospeed %dbps, ispeed %dbps)",
3431 ssh->ospeed, ssh->ispeed);
3432 } else {
3433 ssh->editing = ssh->echoing = 1;
3434 }
3435
3436 if (ssh->cfg.compression) {
3437 send_packet(ssh, SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END);
3438 do {
3439 crReturnV;
3440 } while (!ispkt);
3441 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3442 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3443 bombout(("Protocol confusion"));
3444 crStopV;
3445 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3446 c_write_str(ssh, "Server refused to compress\r\n");
3447 }
3448 logevent("Started compression");
3449 ssh->v1_compressing = TRUE;
3450 ssh->cs_comp_ctx = zlib_compress_init();
3451 logevent("Initialised zlib (RFC1950) compression");
3452 ssh->sc_comp_ctx = zlib_decompress_init();
3453 logevent("Initialised zlib (RFC1950) decompression");
3454 }
3455
3456 /*
3457 * Start the shell or command.
3458 *
3459 * Special case: if the first-choice command is an SSH2
3460 * subsystem (hence not usable here) and the second choice
3461 * exists, we fall straight back to that.
3462 */
3463 {
3464 char *cmd = ssh->cfg.remote_cmd_ptr;
3465
3466 if (ssh->cfg.ssh_subsys && ssh->cfg.remote_cmd_ptr2) {
3467 cmd = ssh->cfg.remote_cmd_ptr2;
3468 ssh->fallback_cmd = TRUE;
3469 }
3470 if (*cmd)
3471 send_packet(ssh, SSH1_CMSG_EXEC_CMD, PKT_STR, cmd, PKT_END);
3472 else
3473 send_packet(ssh, SSH1_CMSG_EXEC_SHELL, PKT_END);
3474 logevent("Started session");
3475 }
3476
3477 ssh->state = SSH_STATE_SESSION;
3478 if (ssh->size_needed)
3479 ssh_size(ssh, ssh->term_width, ssh->term_height);
3480 if (ssh->eof_needed)
3481 ssh_special(ssh, TS_EOF);
3482
3483 if (ssh->ldisc)
3484 ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */
3485 ssh->send_ok = 1;
3486 ssh->channels = newtree234(ssh_channelcmp);
3487 while (1) {
3488 crReturnV;
3489 if (ispkt) {
3490 if (ssh->pktin.type == SSH1_SMSG_STDOUT_DATA ||
3491 ssh->pktin.type == SSH1_SMSG_STDERR_DATA) {
3492 long len = GET_32BIT(ssh->pktin.body);
3493 int bufsize =
3494 from_backend(ssh->frontend,
3495 ssh->pktin.type == SSH1_SMSG_STDERR_DATA,
3496 (char *)(ssh->pktin.body) + 4, len);
3497 if (!ssh->v1_stdout_throttling && bufsize > SSH1_BUFFER_LIMIT) {
3498 ssh->v1_stdout_throttling = 1;
3499 ssh1_throttle(ssh, +1);
3500 }
3501 } else if (ssh->pktin.type == SSH1_MSG_DISCONNECT) {
3502 ssh_closing((Plug)ssh, NULL, 0, 0);
3503 logevent("Received disconnect request");
3504 crStopV;
3505 } else if (ssh->pktin.type == SSH1_SMSG_X11_OPEN) {
3506 /* Remote side is trying to open a channel to talk to our
3507 * X-Server. Give them back a local channel number. */
3508 struct ssh_channel *c;
3509
3510 logevent("Received X11 connect request");
3511 /* Refuse if X11 forwarding is disabled. */
3512 if (!ssh->X11_fwd_enabled) {
3513 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3514 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
3515 logevent("Rejected X11 connect request");
3516 } else {
3517 c = snew(struct ssh_channel);
3518 c->ssh = ssh;
3519
3520 if (x11_init(&c->u.x11.s, ssh->cfg.x11_display, c,
3521 ssh->x11auth, NULL, -1, &ssh->cfg) != NULL) {
3522 logevent("opening X11 forward connection failed");
3523 sfree(c);
3524 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3525 PKT_INT, GET_32BIT(ssh->pktin.body),
3526 PKT_END);
3527 } else {
3528 logevent
3529 ("opening X11 forward connection succeeded");
3530 c->remoteid = GET_32BIT(ssh->pktin.body);
3531 c->localid = alloc_channel_id(ssh);
3532 c->closes = 0;
3533 c->v.v1.throttling = 0;
3534 c->type = CHAN_X11; /* identify channel type */
3535 add234(ssh->channels, c);
3536 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3537 PKT_INT, c->remoteid, PKT_INT,
3538 c->localid, PKT_END);
3539 logevent("Opened X11 forward channel");
3540 }
3541 }
3542 } else if (ssh->pktin.type == SSH1_SMSG_AGENT_OPEN) {
3543 /* Remote side is trying to open a channel to talk to our
3544 * agent. Give them back a local channel number. */
3545 struct ssh_channel *c;
3546
3547 /* Refuse if agent forwarding is disabled. */
3548 if (!ssh->agentfwd_enabled) {
3549 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3550 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
3551 } else {
3552 c = snew(struct ssh_channel);
3553 c->ssh = ssh;
3554 c->remoteid = GET_32BIT(ssh->pktin.body);
3555 c->localid = alloc_channel_id(ssh);
3556 c->closes = 0;
3557 c->v.v1.throttling = 0;
3558 c->type = CHAN_AGENT; /* identify channel type */
3559 c->u.a.lensofar = 0;
3560 add234(ssh->channels, c);
3561 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3562 PKT_INT, c->remoteid, PKT_INT, c->localid,
3563 PKT_END);
3564 }
3565 } else if (ssh->pktin.type == SSH1_MSG_PORT_OPEN) {
3566 /* Remote side is trying to open a channel to talk to a
3567 * forwarded port. Give them back a local channel number. */
3568 struct ssh_channel *c;
3569 struct ssh_rportfwd pf;
3570 int hostsize, port;
3571 char host[256], buf[1024];
3572 char *p, *h;
3573 const char *e;
3574 c = snew(struct ssh_channel);
3575 c->ssh = ssh;
3576
3577 hostsize = GET_32BIT(ssh->pktin.body+4);
3578 for (h = host, p = (char *)(ssh->pktin.body+8);
3579 hostsize != 0; hostsize--) {
3580 if (h+1 < host+sizeof(host))
3581 *h++ = *p;
3582 p++;
3583 }
3584 *h = 0;
3585 port = GET_32BIT(p);
3586
3587 strcpy(pf.dhost, host);
3588 pf.dport = port;
3589
3590 if (find234(ssh->rportfwds, &pf, NULL) == NULL) {
3591 sprintf(buf, "Rejected remote port open request for %s:%d",
3592 host, port);
3593 logevent(buf);
3594 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3595 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
3596 } else {
3597 sprintf(buf, "Received remote port open request for %s:%d",
3598 host, port);
3599 logevent(buf);
3600 e = pfd_newconnect(&c->u.pfd.s, host, port, c, &ssh->cfg);
3601 if (e != NULL) {
3602 char buf[256];
3603 sprintf(buf, "Port open failed: %s", e);
3604 logevent(buf);
3605 sfree(c);
3606 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3607 PKT_INT, GET_32BIT(ssh->pktin.body),
3608 PKT_END);
3609 } else {
3610 c->remoteid = GET_32BIT(ssh->pktin.body);
3611 c->localid = alloc_channel_id(ssh);
3612 c->closes = 0;
3613 c->v.v1.throttling = 0;
3614 c->type = CHAN_SOCKDATA; /* identify channel type */
3615 add234(ssh->channels, c);
3616 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3617 PKT_INT, c->remoteid, PKT_INT,
3618 c->localid, PKT_END);
3619 logevent("Forwarded port opened successfully");
3620 }
3621 }
3622
3623 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_OPEN_CONFIRMATION) {
3624 unsigned int remoteid = GET_32BIT(ssh->pktin.body);
3625 unsigned int localid = GET_32BIT(ssh->pktin.body+4);
3626 struct ssh_channel *c;
3627
3628 c = find234(ssh->channels, &remoteid, ssh_channelfind);
3629 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
3630 c->remoteid = localid;
3631 c->type = CHAN_SOCKDATA;
3632 c->v.v1.throttling = 0;
3633 pfd_confirm(c->u.pfd.s);
3634 }
3635
3636 if (c && c->closes) {
3637 /*
3638 * We have a pending close on this channel,
3639 * which we decided on before the server acked
3640 * the channel open. So now we know the
3641 * remoteid, we can close it again.
3642 */
3643 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE,
3644 PKT_INT, c->remoteid, PKT_END);
3645 }
3646
3647 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_OPEN_FAILURE) {
3648 unsigned int remoteid = GET_32BIT(ssh->pktin.body);
3649 struct ssh_channel *c;
3650
3651 c = find234(ssh->channels, &remoteid, ssh_channelfind);
3652 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
3653 logevent("Forwarded connection refused by server");
3654 pfd_close(c->u.pfd.s);
3655 del234(ssh->channels, c);
3656 sfree(c);
3657 }
3658
3659 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ||
3660 ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION) {
3661 /* Remote side closes a channel. */
3662 unsigned i = GET_32BIT(ssh->pktin.body);
3663 struct ssh_channel *c;
3664 c = find234(ssh->channels, &i, ssh_channelfind);
3665 if (c && ((int)c->remoteid) != -1) {
3666 int closetype;
3667 closetype =
3668 (ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ? 1 : 2);
3669
3670 if ((c->closes == 0) && (c->type == CHAN_X11)) {
3671 logevent("Forwarded X11 connection terminated");
3672 assert(c->u.x11.s != NULL);
3673 x11_close(c->u.x11.s);
3674 c->u.x11.s = NULL;
3675 }
3676 if ((c->closes == 0) && (c->type == CHAN_SOCKDATA)) {
3677 logevent("Forwarded port closed");
3678 assert(c->u.pfd.s != NULL);
3679 pfd_close(c->u.pfd.s);
3680 c->u.pfd.s = NULL;
3681 }
3682
3683 c->closes |= (closetype << 2); /* seen this message */
3684 if (!(c->closes & closetype)) {
3685 send_packet(ssh, ssh->pktin.type, PKT_INT, c->remoteid,
3686 PKT_END);
3687 c->closes |= closetype; /* sent it too */
3688 }
3689
3690 if (c->closes == 15) {
3691 del234(ssh->channels, c);
3692 sfree(c);
3693 }
3694 } else {
3695 bombout(("Received CHANNEL_CLOSE%s for %s channel %d\n",
3696 ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ? "" :
3697 "_CONFIRMATION", c ? "half-open" : "nonexistent",
3698 i));
3699 crStopV;
3700 }
3701 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_DATA) {
3702 /* Data sent down one of our channels. */
3703 int i = GET_32BIT(ssh->pktin.body);
3704 int len = GET_32BIT(ssh->pktin.body + 4);
3705 unsigned char *p = ssh->pktin.body + 8;
3706 struct ssh_channel *c;
3707 c = find234(ssh->channels, &i, ssh_channelfind);
3708 if (c) {
3709 int bufsize = 0;
3710 switch (c->type) {
3711 case CHAN_X11:
3712 bufsize = x11_send(c->u.x11.s, (char *)p, len);
3713 break;
3714 case CHAN_SOCKDATA:
3715 bufsize = pfd_send(c->u.pfd.s, (char *)p, len);
3716 break;
3717 case CHAN_AGENT:
3718 /* Data for an agent message. Buffer it. */
3719 while (len > 0) {
3720 if (c->u.a.lensofar < 4) {
3721 int l = min(4 - c->u.a.lensofar, len);
3722 memcpy(c->u.a.msglen + c->u.a.lensofar, p,
3723 l);
3724 p += l;
3725 len -= l;
3726 c->u.a.lensofar += l;
3727 }
3728 if (c->u.a.lensofar == 4) {
3729 c->u.a.totallen =
3730 4 + GET_32BIT(c->u.a.msglen);
3731 c->u.a.message = snewn(c->u.a.totallen,
3732 unsigned char);
3733 memcpy(c->u.a.message, c->u.a.msglen, 4);
3734 }
3735 if (c->u.a.lensofar >= 4 && len > 0) {
3736 int l =
3737 min(c->u.a.totallen - c->u.a.lensofar,
3738 len);
3739 memcpy(c->u.a.message + c->u.a.lensofar, p,
3740 l);
3741 p += l;
3742 len -= l;
3743 c->u.a.lensofar += l;
3744 }
3745 if (c->u.a.lensofar == c->u.a.totallen) {
3746 void *reply;
3747 int replylen;
3748 if (agent_query(c->u.a.message,
3749 c->u.a.totallen,
3750 &reply, &replylen,
3751 ssh_agentf_callback, c))
3752 ssh_agentf_callback(c, reply, replylen);
3753 sfree(c->u.a.message);
3754 c->u.a.lensofar = 0;
3755 }
3756 }
3757 bufsize = 0; /* agent channels never back up */
3758 break;
3759 }
3760 if (!c->v.v1.throttling && bufsize > SSH1_BUFFER_LIMIT) {
3761 c->v.v1.throttling = 1;
3762 ssh1_throttle(ssh, +1);
3763 }
3764 }
3765 } else if (ssh->pktin.type == SSH1_SMSG_SUCCESS) {
3766 /* may be from EXEC_SHELL on some servers */
3767 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3768 /* may be from EXEC_SHELL on some servers
3769 * if no pty is available or in other odd cases. Ignore */
3770 } else if (ssh->pktin.type == SSH1_SMSG_EXIT_STATUS) {
3771 char buf[100];
3772 ssh->exitcode = GET_32BIT(ssh->pktin.body);
3773 sprintf(buf, "Server sent command exit status %d",
3774 ssh->exitcode);
3775 logevent(buf);
3776 send_packet(ssh, SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
3777 /*
3778 * In case `helpful' firewalls or proxies tack
3779 * extra human-readable text on the end of the
3780 * session which we might mistake for another
3781 * encrypted packet, we close the session once
3782 * we've sent EXIT_CONFIRMATION.
3783 */
3784 ssh_closing((Plug)ssh, NULL, 0, 0);
3785 crStopV;
3786 } else {
3787 bombout(("Strange packet received: type %d", ssh->pktin.type));
3788 crStopV;
3789 }
3790 } else {
3791 while (inlen > 0) {
3792 int len = min(inlen, 512);
3793 send_packet(ssh, SSH1_CMSG_STDIN_DATA,
3794 PKT_INT, len, PKT_DATA, in, len, PKT_END);
3795 in += len;
3796 inlen -= len;
3797 }
3798 }
3799 }
3800
3801 crFinishV;
3802 }
3803
3804 /*
3805 * Utility routine for decoding comma-separated strings in KEXINIT.
3806 */
3807 static int in_commasep_string(char *needle, char *haystack, int haylen)
3808 {
3809 int needlen;
3810 if (!needle || !haystack) /* protect against null pointers */
3811 return 0;
3812 needlen = strlen(needle);
3813 while (1) {
3814 /*
3815 * Is it at the start of the string?
3816 */
3817 if (haylen >= needlen && /* haystack is long enough */
3818 !memcmp(needle, haystack, needlen) && /* initial match */
3819 (haylen == needlen || haystack[needlen] == ',')
3820 /* either , or EOS follows */
3821 )
3822 return 1;
3823 /*
3824 * If not, search for the next comma and resume after that.
3825 * If no comma found, terminate.
3826 */
3827 while (haylen > 0 && *haystack != ',')
3828 haylen--, haystack++;
3829 if (haylen == 0)
3830 return 0;
3831 haylen--, haystack++; /* skip over comma itself */
3832 }
3833 }
3834
3835 /*
3836 * SSH2 key creation method.
3837 */
3838 static void ssh2_mkkey(Ssh ssh, Bignum K, unsigned char *H,
3839 unsigned char *sessid, char chr,
3840 unsigned char *keyspace)
3841 {
3842 SHA_State s;
3843 /* First 20 bytes. */
3844 SHA_Init(&s);
3845 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
3846 sha_mpint(&s, K);
3847 SHA_Bytes(&s, H, 20);
3848 SHA_Bytes(&s, &chr, 1);
3849 SHA_Bytes(&s, sessid, 20);
3850 SHA_Final(&s, keyspace);
3851 /* Next 20 bytes. */
3852 SHA_Init(&s);
3853 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
3854 sha_mpint(&s, K);
3855 SHA_Bytes(&s, H, 20);
3856 SHA_Bytes(&s, keyspace, 20);
3857 SHA_Final(&s, keyspace + 20);
3858 }
3859
3860 /*
3861 * Handle the SSH2 transport layer.
3862 */
3863 static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
3864 {
3865 struct do_ssh2_transport_state {
3866 int nbits, pbits, warn;
3867 Bignum p, g, e, f, K;
3868 int kex_init_value, kex_reply_value;
3869 const struct ssh_mac **maclist;
3870 int nmacs;
3871 const struct ssh2_cipher *cscipher_tobe;
3872 const struct ssh2_cipher *sccipher_tobe;
3873 const struct ssh_mac *csmac_tobe;
3874 const struct ssh_mac *scmac_tobe;
3875 const struct ssh_compress *cscomp_tobe;
3876 const struct ssh_compress *sccomp_tobe;
3877 char *hostkeydata, *sigdata, *keystr, *fingerprint;
3878 int hostkeylen, siglen;
3879 void *hkey; /* actual host key */
3880 unsigned char exchange_hash[20];
3881 int n_preferred_ciphers;
3882 const struct ssh2_ciphers *preferred_ciphers[CIPHER_MAX];
3883 const struct ssh_compress *preferred_comp;
3884 int first_kex;
3885 };
3886 crState(do_ssh2_transport_state);
3887
3888 crBegin(ssh->do_ssh2_transport_crstate);
3889
3890 s->cscipher_tobe = s->sccipher_tobe = NULL;
3891 s->csmac_tobe = s->scmac_tobe = NULL;
3892 s->cscomp_tobe = s->sccomp_tobe = NULL;
3893
3894 random_init();
3895 s->first_kex = 1;
3896
3897 {
3898 int i;
3899 /*
3900 * Set up the preferred ciphers. (NULL => warn below here)
3901 */
3902 s->n_preferred_ciphers = 0;
3903 for (i = 0; i < CIPHER_MAX; i++) {
3904 switch (ssh->cfg.ssh_cipherlist[i]) {
3905 case CIPHER_BLOWFISH:
3906 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_blowfish;
3907 break;
3908 case CIPHER_DES:
3909 if (ssh->cfg.ssh2_des_cbc) {
3910 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_des;
3911 }
3912 break;
3913 case CIPHER_3DES:
3914 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_3des;
3915 break;
3916 case CIPHER_AES:
3917 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_aes;
3918 break;
3919 case CIPHER_WARN:
3920 /* Flag for later. Don't bother if it's the last in
3921 * the list. */
3922 if (i < CIPHER_MAX - 1) {
3923 s->preferred_ciphers[s->n_preferred_ciphers++] = NULL;
3924 }
3925 break;
3926 }
3927 }
3928 }
3929
3930 /*
3931 * Set up preferred compression.
3932 */
3933 if (ssh->cfg.compression)
3934 s->preferred_comp = &ssh_zlib;
3935 else
3936 s->preferred_comp = &ssh_comp_none;
3937
3938 /*
3939 * Be prepared to work around the buggy MAC problem.
3940 */
3941 if (ssh->remote_bugs & BUG_SSH2_HMAC)
3942 s->maclist = buggymacs, s->nmacs = lenof(buggymacs);
3943 else
3944 s->maclist = macs, s->nmacs = lenof(macs);
3945
3946 begin_key_exchange:
3947 {
3948 int i, j, cipherstr_started;
3949
3950 /*
3951 * Construct and send our key exchange packet.
3952 */
3953 ssh2_pkt_init(ssh, SSH2_MSG_KEXINIT);
3954 for (i = 0; i < 16; i++)
3955 ssh2_pkt_addbyte(ssh, (unsigned char) random_byte());
3956 /* List key exchange algorithms. */
3957 ssh2_pkt_addstring_start(ssh);
3958 for (i = 0; i < lenof(kex_algs); i++) {
3959 if (kex_algs[i] == &ssh_diffiehellman_gex &&
3960 (ssh->remote_bugs & BUG_SSH2_DH_GEX))
3961 continue;
3962 ssh2_pkt_addstring_str(ssh, kex_algs[i]->name);
3963 if (i < lenof(kex_algs) - 1)
3964 ssh2_pkt_addstring_str(ssh, ",");
3965 }
3966 /* List server host key algorithms. */
3967 ssh2_pkt_addstring_start(ssh);
3968 for (i = 0; i < lenof(hostkey_algs); i++) {
3969 ssh2_pkt_addstring_str(ssh, hostkey_algs[i]->name);
3970 if (i < lenof(hostkey_algs) - 1)
3971 ssh2_pkt_addstring_str(ssh, ",");
3972 }
3973 /* List client->server encryption algorithms. */
3974 ssh2_pkt_addstring_start(ssh);
3975 cipherstr_started = 0;
3976 for (i = 0; i < s->n_preferred_ciphers; i++) {
3977 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3978 if (!c) continue; /* warning flag */
3979 for (j = 0; j < c->nciphers; j++) {
3980 if (cipherstr_started)
3981 ssh2_pkt_addstring_str(ssh, ",");
3982 ssh2_pkt_addstring_str(ssh, c->list[j]->name);
3983 cipherstr_started = 1;
3984 }
3985 }
3986 /* List server->client encryption algorithms. */
3987 ssh2_pkt_addstring_start(ssh);
3988 cipherstr_started = 0;
3989 for (i = 0; i < s->n_preferred_ciphers; i++) {
3990 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3991 if (!c) continue; /* warning flag */
3992 for (j = 0; j < c->nciphers; j++) {
3993 if (cipherstr_started)
3994 ssh2_pkt_addstring_str(ssh, ",");
3995 ssh2_pkt_addstring_str(ssh, c->list[j]->name);
3996 cipherstr_started = 1;
3997 }
3998 }
3999 /* List client->server MAC algorithms. */
4000 ssh2_pkt_addstring_start(ssh);
4001 for (i = 0; i < s->nmacs; i++) {
4002 ssh2_pkt_addstring_str(ssh, s->maclist[i]->name);
4003 if (i < s->nmacs - 1)
4004 ssh2_pkt_addstring_str(ssh, ",");
4005 }
4006 /* List server->client MAC algorithms. */
4007 ssh2_pkt_addstring_start(ssh);
4008 for (i = 0; i < s->nmacs; i++) {
4009 ssh2_pkt_addstring_str(ssh, s->maclist[i]->name);
4010 if (i < s->nmacs - 1)
4011 ssh2_pkt_addstring_str(ssh, ",");
4012 }
4013 /* List client->server compression algorithms. */
4014 ssh2_pkt_addstring_start(ssh);
4015 for (i = 0; i < lenof(compressions) + 1; i++) {
4016 const struct ssh_compress *c =
4017 i == 0 ? s->preferred_comp : compressions[i - 1];
4018 ssh2_pkt_addstring_str(ssh, c->name);
4019 if (i < lenof(compressions))
4020 ssh2_pkt_addstring_str(ssh, ",");
4021 }
4022 /* List server->client compression algorithms. */
4023 ssh2_pkt_addstring_start(ssh);
4024 for (i = 0; i < lenof(compressions) + 1; i++) {
4025 const struct ssh_compress *c =
4026 i == 0 ? s->preferred_comp : compressions[i - 1];
4027 ssh2_pkt_addstring_str(ssh, c->name);
4028 if (i < lenof(compressions))
4029 ssh2_pkt_addstring_str(ssh, ",");
4030 }
4031 /* List client->server languages. Empty list. */
4032 ssh2_pkt_addstring_start(ssh);
4033 /* List server->client languages. Empty list. */
4034 ssh2_pkt_addstring_start(ssh);
4035 /* First KEX packet does _not_ follow, because we're not that brave. */
4036 ssh2_pkt_addbool(ssh, FALSE);
4037 /* Reserved. */
4038 ssh2_pkt_adduint32(ssh, 0);
4039 }
4040
4041 ssh->exhash = ssh->exhashbase;
4042 sha_string(&ssh->exhash, ssh->pktout.data + 5, ssh->pktout.length - 5);
4043
4044 ssh2_pkt_send(ssh);
4045
4046 if (!ispkt)
4047 crWaitUntil(ispkt);
4048 if (ssh->pktin.length > 5)
4049 sha_string(&ssh->exhash, ssh->pktin.data + 5, ssh->pktin.length - 5);
4050
4051 /*
4052 * Now examine the other side's KEXINIT to see what we're up
4053 * to.
4054 */
4055 {
4056 char *str;
4057 int i, j, len;
4058
4059 if (ssh->pktin.type != SSH2_MSG_KEXINIT) {
4060 bombout(("expected key exchange packet from server"));
4061 crStop(0);
4062 }
4063 ssh->kex = NULL;
4064 ssh->hostkey = NULL;
4065 s->cscipher_tobe = NULL;
4066 s->sccipher_tobe = NULL;
4067 s->csmac_tobe = NULL;
4068 s->scmac_tobe = NULL;
4069 s->cscomp_tobe = NULL;
4070 s->sccomp_tobe = NULL;
4071 ssh->pktin.savedpos += 16; /* skip garbage cookie */
4072 ssh2_pkt_getstring(ssh, &str, &len); /* key exchange algorithms */
4073 for (i = 0; i < lenof(kex_algs); i++) {
4074 if (kex_algs[i] == &ssh_diffiehellman_gex &&
4075 (ssh->remote_bugs & BUG_SSH2_DH_GEX))
4076 continue;
4077 if (in_commasep_string(kex_algs[i]->name, str, len)) {
4078 ssh->kex = kex_algs[i];
4079 break;
4080 }
4081 }
4082 ssh2_pkt_getstring(ssh, &str, &len); /* host key algorithms */
4083 for (i = 0; i < lenof(hostkey_algs); i++) {
4084 if (in_commasep_string(hostkey_algs[i]->name, str, len)) {
4085 ssh->hostkey = hostkey_algs[i];
4086 break;
4087 }
4088 }
4089 ssh2_pkt_getstring(ssh, &str, &len); /* client->server cipher */
4090 s->warn = 0;
4091 for (i = 0; i < s->n_preferred_ciphers; i++) {
4092 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
4093 if (!c) {
4094 s->warn = 1;
4095 } else {
4096 for (j = 0; j < c->nciphers; j++) {
4097 if (in_commasep_string(c->list[j]->name, str, len)) {
4098 s->cscipher_tobe = c->list[j];
4099 break;
4100 }
4101 }
4102 }
4103 if (s->cscipher_tobe) {
4104 if (s->warn)
4105 askcipher(ssh->frontend, s->cscipher_tobe->name, 1);
4106 break;
4107 }
4108 }
4109 if (!s->cscipher_tobe) {
4110 bombout(("Couldn't agree a client-to-server cipher (available: %s)",
4111 str ? str : "(null)"));
4112 crStop(0);
4113 }
4114
4115 ssh2_pkt_getstring(ssh, &str, &len); /* server->client cipher */
4116 s->warn = 0;
4117 for (i = 0; i < s->n_preferred_ciphers; i++) {
4118 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
4119 if (!c) {
4120 s->warn = 1;
4121 } else {
4122 for (j = 0; j < c->nciphers; j++) {
4123 if (in_commasep_string(c->list[j]->name, str, len)) {
4124 s->sccipher_tobe = c->list[j];
4125 break;
4126 }
4127 }
4128 }
4129 if (s->sccipher_tobe) {
4130 if (s->warn)
4131 askcipher(ssh->frontend, s->sccipher_tobe->name, 2);
4132 break;
4133 }
4134 }
4135 if (!s->sccipher_tobe) {
4136 bombout(("Couldn't agree a server-to-client cipher (available: %s)",
4137 str ? str : "(null)"));
4138 crStop(0);
4139 }
4140
4141 ssh2_pkt_getstring(ssh, &str, &len); /* client->server mac */
4142 for (i = 0; i < s->nmacs; i++) {
4143 if (in_commasep_string(s->maclist[i]->name, str, len)) {
4144 s->csmac_tobe = s->maclist[i];
4145 break;
4146 }
4147 }
4148 ssh2_pkt_getstring(ssh, &str, &len); /* server->client mac */
4149 for (i = 0; i < s->nmacs; i++) {
4150 if (in_commasep_string(s->maclist[i]->name, str, len)) {
4151 s->scmac_tobe = s->maclist[i];
4152 break;
4153 }
4154 }
4155 ssh2_pkt_getstring(ssh, &str, &len); /* client->server compression */
4156 for (i = 0; i < lenof(compressions) + 1; i++) {
4157 const struct ssh_compress *c =
4158 i == 0 ? s->preferred_comp : compressions[i - 1];
4159 if (in_commasep_string(c->name, str, len)) {
4160 s->cscomp_tobe = c;
4161 break;
4162 }
4163 }
4164 ssh2_pkt_getstring(ssh, &str, &len); /* server->client compression */
4165 for (i = 0; i < lenof(compressions) + 1; i++) {
4166 const struct ssh_compress *c =
4167 i == 0 ? s->preferred_comp : compressions[i - 1];
4168 if (in_commasep_string(c->name, str, len)) {
4169 s->sccomp_tobe = c;
4170 break;
4171 }
4172 }
4173 }
4174
4175 /*
4176 * Work out the number of bits of key we will need from the key
4177 * exchange. We start with the maximum key length of either
4178 * cipher...
4179 */
4180 {
4181 int csbits, scbits;
4182
4183 csbits = s->cscipher_tobe->keylen;
4184 scbits = s->sccipher_tobe->keylen;
4185 s->nbits = (csbits > scbits ? csbits : scbits);
4186 }
4187 /* The keys only have 160-bit entropy, since they're based on
4188 * a SHA-1 hash. So cap the key size at 160 bits. */
4189 if (s->nbits > 160)
4190 s->nbits = 160;
4191
4192 /*
4193 * If we're doing Diffie-Hellman group exchange, start by
4194 * requesting a group.
4195 */
4196 if (ssh->kex == &ssh_diffiehellman_gex) {
4197 logevent("Doing Diffie-Hellman group exchange");
4198 ssh->pkt_ctx |= SSH2_PKTCTX_DHGEX;
4199 /*
4200 * Work out how big a DH group we will need to allow that
4201 * much data.
4202 */
4203 s->pbits = 512 << ((s->nbits - 1) / 64);
4204 ssh2_pkt_init(ssh, SSH2_MSG_KEX_DH_GEX_REQUEST);
4205 ssh2_pkt_adduint32(ssh, s->pbits);
4206 ssh2_pkt_send(ssh);
4207
4208 crWaitUntil(ispkt);
4209 if (ssh->pktin.type != SSH2_MSG_KEX_DH_GEX_GROUP) {
4210 bombout(("expected key exchange group packet from server"));
4211 crStop(0);
4212 }
4213 s->p = ssh2_pkt_getmp(ssh);
4214 s->g = ssh2_pkt_getmp(ssh);
4215 ssh->kex_ctx = dh_setup_group(s->p, s->g);
4216 s->kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT;
4217 s->kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY;
4218 } else {
4219 ssh->pkt_ctx |= SSH2_PKTCTX_DHGROUP1;
4220 ssh->kex_ctx = dh_setup_group1();
4221 s->kex_init_value = SSH2_MSG_KEXDH_INIT;
4222 s->kex_reply_value = SSH2_MSG_KEXDH_REPLY;
4223 }
4224
4225 logevent("Doing Diffie-Hellman key exchange");
4226 /*
4227 * Now generate and send e for Diffie-Hellman.
4228 */
4229 s->e = dh_create_e(ssh->kex_ctx, s->nbits * 2);
4230 ssh2_pkt_init(ssh, s->kex_init_value);
4231 ssh2_pkt_addmp(ssh, s->e);
4232 ssh2_pkt_send(ssh);
4233
4234 crWaitUntil(ispkt);
4235 if (ssh->pktin.type != s->kex_reply_value) {
4236 bombout(("expected key exchange reply packet from server"));
4237 crStop(0);
4238 }
4239 ssh2_pkt_getstring(ssh, &s->hostkeydata, &s->hostkeylen);
4240 s->f = ssh2_pkt_getmp(ssh);
4241 ssh2_pkt_getstring(ssh, &s->sigdata, &s->siglen);
4242
4243 s->K = dh_find_K(ssh->kex_ctx, s->f);
4244
4245 sha_string(&ssh->exhash, s->hostkeydata, s->hostkeylen);
4246 if (ssh->kex == &ssh_diffiehellman_gex) {
4247 sha_uint32(&ssh->exhash, s->pbits);
4248 sha_mpint(&ssh->exhash, s->p);
4249 sha_mpint(&ssh->exhash, s->g);
4250 }
4251 sha_mpint(&ssh->exhash, s->e);
4252 sha_mpint(&ssh->exhash, s->f);
4253 sha_mpint(&ssh->exhash, s->K);
4254 SHA_Final(&ssh->exhash, s->exchange_hash);
4255
4256 dh_cleanup(ssh->kex_ctx);
4257 ssh->kex_ctx = NULL;
4258
4259 #if 0
4260 debug(("Exchange hash is:\n"));
4261 dmemdump(s->exchange_hash, 20);
4262 #endif
4263
4264 s->hkey = ssh->hostkey->newkey(s->hostkeydata, s->hostkeylen);
4265 if (!s->hkey ||
4266 !ssh->hostkey->verifysig(s->hkey, s->sigdata, s->siglen,
4267 (char *)s->exchange_hash, 20)) {
4268 bombout(("Server's host key did not match the signature supplied"));
4269 crStop(0);
4270 }
4271
4272 /*
4273 * Authenticate remote host: verify host key. (We've already
4274 * checked the signature of the exchange hash.)
4275 */
4276 s->keystr = ssh->hostkey->fmtkey(s->hkey);
4277 s->fingerprint = ssh->hostkey->fingerprint(s->hkey);
4278 verify_ssh_host_key(ssh->frontend,
4279 ssh->savedhost, ssh->savedport, ssh->hostkey->keytype,
4280 s->keystr, s->fingerprint);
4281 if (s->first_kex) { /* don't bother logging this in rekeys */
4282 logevent("Host key fingerprint is:");
4283 logevent(s->fingerprint);
4284 }
4285 sfree(s->fingerprint);
4286 sfree(s->keystr);
4287 ssh->hostkey->freekey(s->hkey);
4288
4289 /*
4290 * Send SSH2_MSG_NEWKEYS.
4291 */
4292 ssh2_pkt_init(ssh, SSH2_MSG_NEWKEYS);
4293 ssh2_pkt_send(ssh);
4294
4295 /*
4296 * Expect SSH2_MSG_NEWKEYS from server.
4297 */
4298 crWaitUntil(ispkt);
4299 if (ssh->pktin.type != SSH2_MSG_NEWKEYS) {
4300 bombout(("expected new-keys packet from server"));
4301 crStop(0);
4302 }
4303
4304 /*
4305 * Create and initialise session keys.
4306 */
4307 if (ssh->cs_cipher_ctx)
4308 ssh->cscipher->free_context(ssh->cs_cipher_ctx);
4309 ssh->cscipher = s->cscipher_tobe;
4310 ssh->cs_cipher_ctx = ssh->cscipher->make_context();
4311
4312 if (ssh->sc_cipher_ctx)
4313 ssh->sccipher->free_context(ssh->sc_cipher_ctx);
4314 ssh->sccipher = s->sccipher_tobe;
4315 ssh->sc_cipher_ctx = ssh->sccipher->make_context();
4316
4317 if (ssh->cs_mac_ctx)
4318 ssh->csmac->free_context(ssh->cs_mac_ctx);
4319 ssh->csmac = s->csmac_tobe;
4320 ssh->cs_mac_ctx = ssh->csmac->make_context();
4321
4322 if (ssh->sc_mac_ctx)
4323 ssh->scmac->free_context(ssh->sc_mac_ctx);
4324 ssh->scmac = s->scmac_tobe;
4325 ssh->sc_mac_ctx = ssh->scmac->make_context();
4326
4327 if (ssh->cs_comp_ctx)
4328 ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
4329 ssh->cscomp = s->cscomp_tobe;
4330 ssh->cs_comp_ctx = ssh->cscomp->compress_init();
4331
4332 if (ssh->sc_comp_ctx)
4333 ssh->sccomp->decompress_cleanup(ssh->sc_comp_ctx);
4334 ssh->sccomp = s->sccomp_tobe;
4335 ssh->sc_comp_ctx = ssh->sccomp->decompress_init();
4336
4337 /*
4338 * Set IVs after keys. Here we use the exchange hash from the
4339 * _first_ key exchange.
4340 */
4341 {
4342 unsigned char keyspace[40];
4343 if (s->first_kex)
4344 memcpy(ssh->v2_session_id, s->exchange_hash,
4345 sizeof(s->exchange_hash));
4346 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'C',keyspace);
4347 ssh->cscipher->setkey(ssh->cs_cipher_ctx, keyspace);
4348 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'D',keyspace);
4349 ssh->sccipher->setkey(ssh->sc_cipher_ctx, keyspace);
4350 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'A',keyspace);
4351 ssh->cscipher->setiv(ssh->cs_cipher_ctx, keyspace);
4352 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'B',keyspace);
4353 ssh->sccipher->setiv(ssh->sc_cipher_ctx, keyspace);
4354 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'E',keyspace);
4355 ssh->csmac->setkey(ssh->cs_mac_ctx, keyspace);
4356 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'F',keyspace);
4357 ssh->scmac->setkey(ssh->sc_mac_ctx, keyspace);
4358 }
4359 logeventf(ssh, "Initialised %.200s client->server encryption",
4360 ssh->cscipher->text_name);
4361 logeventf(ssh, "Initialised %.200s server->client encryption",
4362 ssh->sccipher->text_name);
4363 if (ssh->cscomp->text_name)
4364 logeventf(ssh, "Initialised %s compression",
4365 ssh->cscomp->text_name);
4366 if (ssh->sccomp->text_name)
4367 logeventf(ssh, "Initialised %s decompression",
4368 ssh->sccomp->text_name);
4369 freebn(s->f);
4370 freebn(s->K);
4371 if (ssh->kex == &ssh_diffiehellman_gex) {
4372 freebn(s->g);
4373 freebn(s->p);
4374 }
4375
4376 /*
4377 * If this is the first key exchange phase, we must pass the
4378 * SSH2_MSG_NEWKEYS packet to the next layer, not because it
4379 * wants to see it but because it will need time to initialise
4380 * itself before it sees an actual packet. In subsequent key
4381 * exchange phases, we don't pass SSH2_MSG_NEWKEYS on, because
4382 * it would only confuse the layer above.
4383 */
4384 if (!s->first_kex) {
4385 crReturn(0);
4386 }
4387 s->first_kex = 0;
4388
4389 /*
4390 * Now we're encrypting. Begin returning 1 to the protocol main
4391 * function so that other things can run on top of the
4392 * transport. If we ever see a KEXINIT, we must go back to the
4393 * start.
4394 */
4395 while (!(ispkt && ssh->pktin.type == SSH2_MSG_KEXINIT)) {
4396 crReturn(1);
4397 }
4398 logevent("Server initiated key re-exchange");
4399 goto begin_key_exchange;
4400
4401 crFinish(1);
4402 }
4403
4404 /*
4405 * Add data to an SSH2 channel output buffer.
4406 */
4407 static void ssh2_add_channel_data(struct ssh_channel *c, char *buf,
4408 int len)
4409 {
4410 bufchain_add(&c->v.v2.outbuffer, buf, len);
4411 }
4412
4413 /*
4414 * Attempt to send data on an SSH2 channel.
4415 */
4416 static int ssh2_try_send(struct ssh_channel *c)
4417 {
4418 Ssh ssh = c->ssh;
4419
4420 while (c->v.v2.remwindow > 0 && bufchain_size(&c->v.v2.outbuffer) > 0) {
4421 int len;
4422 void *data;
4423 bufchain_prefix(&c->v.v2.outbuffer, &data, &len);
4424 if ((unsigned)len > c->v.v2.remwindow)
4425 len = c->v.v2.remwindow;
4426 if ((unsigned)len > c->v.v2.remmaxpkt)
4427 len = c->v.v2.remmaxpkt;
4428 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_DATA);
4429 ssh2_pkt_adduint32(ssh, c->remoteid);
4430 ssh2_pkt_addstring_start(ssh);
4431 ssh2_pkt_addstring_data(ssh, data, len);
4432 ssh2_pkt_send(ssh);
4433 bufchain_consume(&c->v.v2.outbuffer, len);
4434 c->v.v2.remwindow -= len;
4435 }
4436
4437 /*
4438 * After having sent as much data as we can, return the amount
4439 * still buffered.
4440 */
4441 return bufchain_size(&c->v.v2.outbuffer);
4442 }
4443
4444 /*
4445 * Potentially enlarge the window on an SSH2 channel.
4446 */
4447 static void ssh2_set_window(struct ssh_channel *c, unsigned newwin)
4448 {
4449 Ssh ssh = c->ssh;
4450
4451 /*
4452 * Never send WINDOW_ADJUST for a channel that the remote side
4453 * already thinks it's closed; there's no point, since it won't
4454 * be sending any more data anyway.
4455 */
4456 if (c->closes != 0)
4457 return;
4458
4459 if (newwin > c->v.v2.locwindow) {
4460 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST);
4461 ssh2_pkt_adduint32(ssh, c->remoteid);
4462 ssh2_pkt_adduint32(ssh, newwin - c->v.v2.locwindow);
4463 ssh2_pkt_send(ssh);
4464 c->v.v2.locwindow = newwin;
4465 }
4466 }
4467
4468 /*
4469 * Handle the SSH2 userauth and connection layers.
4470 */
4471 static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
4472 {
4473 struct do_ssh2_authconn_state {
4474 enum {
4475 AUTH_INVALID, AUTH_PUBLICKEY_AGENT, AUTH_PUBLICKEY_FILE,
4476 AUTH_PASSWORD,
4477 AUTH_KEYBOARD_INTERACTIVE
4478 } method;
4479 enum {
4480 AUTH_TYPE_NONE,
4481 AUTH_TYPE_PUBLICKEY,
4482 AUTH_TYPE_PUBLICKEY_OFFER_LOUD,
4483 AUTH_TYPE_PUBLICKEY_OFFER_QUIET,
4484 AUTH_TYPE_PASSWORD,
4485 AUTH_TYPE_KEYBOARD_INTERACTIVE,
4486 AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET
4487 } type;
4488 int gotit, need_pw, can_pubkey, can_passwd, can_keyb_inter;
4489 int tried_pubkey_config, tried_agent, tried_keyb_inter;
4490 int kbd_inter_running;
4491 int we_are_in;
4492 int num_prompts, curr_prompt, echo;
4493 char username[100];
4494 int got_username;
4495 char pwprompt[200];
4496 char password[100];
4497 void *publickey_blob;
4498 int publickey_bloblen;
4499 unsigned char request[5], *response, *p;
4500 int responselen;
4501 int keyi, nkeys;
4502 int authed;
4503 char *pkblob, *alg, *commentp;
4504 int pklen, alglen, commentlen;
4505 int siglen, retlen, len;
4506 char *q, *agentreq, *ret;
4507 int try_send;
4508 };
4509 crState(do_ssh2_authconn_state);
4510
4511 crBegin(ssh->do_ssh2_authconn_crstate);
4512
4513 /*
4514 * Request userauth protocol, and await a response to it.
4515 */
4516 ssh2_pkt_init(ssh, SSH2_MSG_SERVICE_REQUEST);
4517 ssh2_pkt_addstring(ssh, "ssh-userauth");
4518 ssh2_pkt_send(ssh);
4519 crWaitUntilV(ispkt);
4520 if (ssh->pktin.type != SSH2_MSG_SERVICE_ACCEPT) {
4521 bombout(("Server refused user authentication protocol"));
4522 crStopV;
4523 }
4524
4525 /*
4526 * We repeat this whole loop, including the username prompt,
4527 * until we manage a successful authentication. If the user
4528 * types the wrong _password_, they can be sent back to the
4529 * beginning to try another username, if this is configured on.
4530 * (If they specify a username in the config, they are never
4531 * asked, even if they do give a wrong password.)
4532 *
4533 * I think this best serves the needs of
4534 *
4535 * - the people who have no configuration, no keys, and just
4536 * want to try repeated (username,password) pairs until they
4537 * type both correctly
4538 *
4539 * - people who have keys and configuration but occasionally
4540 * need to fall back to passwords
4541 *
4542 * - people with a key held in Pageant, who might not have
4543 * logged in to a particular machine before; so they want to
4544 * type a username, and then _either_ their key will be
4545 * accepted, _or_ they will type a password. If they mistype
4546 * the username they will want to be able to get back and
4547 * retype it!
4548 */
4549 s->username[0] = '\0';
4550 s->got_username = FALSE;
4551 do {
4552 /*
4553 * Get a username.
4554 */
4555 if (s->got_username && !ssh->cfg.change_username) {
4556 /*
4557 * We got a username last time round this loop, and
4558 * with change_username turned off we don't try to get
4559 * it again.
4560 */
4561 } else if ((flags & FLAG_INTERACTIVE) && !*ssh->cfg.username) {
4562 if (ssh_get_line && !ssh_getline_pw_only) {
4563 if (!ssh_get_line("login as: ",
4564 s->username, sizeof(s->username), FALSE)) {
4565 /*
4566 * get_line failed to get a username.
4567 * Terminate.
4568 */
4569 logevent("No username provided. Abandoning session.");
4570 ssh_closing((Plug)ssh, NULL, 0, 0);
4571 crStopV;
4572 }
4573 } else {
4574 int ret; /* need not be saved across crReturn */
4575 c_write_str(ssh, "login as: ");
4576 ssh->send_ok = 1;
4577 setup_userpass_input(ssh, s->username, sizeof(s->username), 1);
4578 do {
4579 crWaitUntilV(!ispkt);
4580 ret = process_userpass_input(ssh, in, inlen);
4581 } while (ret == 0);
4582 if (ret < 0)
4583 cleanup_exit(0);
4584 c_write_str(ssh, "\r\n");
4585 }
4586 s->username[strcspn(s->username, "\n\r")] = '\0';
4587 } else {
4588 char *stuff;
4589 strncpy(s->username, ssh->cfg.username, sizeof(s->username));
4590 s->username[sizeof(s->username)-1] = '\0';
4591 if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
4592 stuff = dupprintf("Using username \"%s\".\r\n", s->username);
4593 c_write_str(ssh, stuff);
4594 sfree(stuff);
4595 }
4596 }
4597 s->got_username = TRUE;
4598
4599 /*
4600 * Send an authentication request using method "none": (a)
4601 * just in case it succeeds, and (b) so that we know what
4602 * authentication methods we can usefully try next.
4603 */
4604 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4605
4606 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4607 ssh2_pkt_addstring(ssh, s->username);
4608 ssh2_pkt_addstring(ssh, "ssh-connection");/* service requested */
4609 ssh2_pkt_addstring(ssh, "none"); /* method */
4610 ssh2_pkt_send(ssh);
4611 s->type = AUTH_TYPE_NONE;
4612 s->gotit = FALSE;
4613 s->we_are_in = FALSE;
4614
4615 s->tried_pubkey_config = FALSE;
4616 s->tried_agent = FALSE;
4617 s->tried_keyb_inter = FALSE;
4618 s->kbd_inter_running = FALSE;
4619 /* Load the pub half of ssh->cfg.keyfile so we notice if it's in Pageant */
4620 if (!filename_is_null(ssh->cfg.keyfile)) {
4621 int keytype;
4622 logeventf(ssh, "Reading private key file \"%.150s\"",
4623 filename_to_str(&ssh->cfg.keyfile));
4624 keytype = key_type(&ssh->cfg.keyfile);
4625 if (keytype == SSH_KEYTYPE_SSH2) {
4626 s->publickey_blob =
4627 ssh2_userkey_loadpub(&ssh->cfg.keyfile, NULL,
4628 &s->publickey_bloblen, NULL);
4629 } else {
4630 char *msgbuf;
4631 logeventf(ssh, "Unable to use this key file (%s)",
4632 key_type_to_str(keytype));
4633 msgbuf = dupprintf("Unable to use key file \"%.150s\""
4634 " (%s)\r\n",
4635 filename_to_str(&ssh->cfg.keyfile),
4636 key_type_to_str(keytype));
4637 c_write_str(ssh, msgbuf);
4638 sfree(msgbuf);
4639 s->publickey_blob = NULL;
4640 }
4641 } else
4642 s->publickey_blob = NULL;
4643
4644 while (1) {
4645 /*
4646 * Wait for the result of the last authentication request.
4647 */
4648 if (!s->gotit)
4649 crWaitUntilV(ispkt);
4650 while (ssh->pktin.type == SSH2_MSG_USERAUTH_BANNER) {
4651 char *banner;
4652 int size;
4653 /*
4654 * Don't show the banner if we're operating in
4655 * non-verbose non-interactive mode. (It's probably
4656 * a script, which means nobody will read the
4657 * banner _anyway_, and moreover the printing of
4658 * the banner will screw up processing on the
4659 * output of (say) plink.)
4660 */
4661 if (flags & (FLAG_VERBOSE | FLAG_INTERACTIVE)) {
4662 ssh2_pkt_getstring(ssh, &banner, &size);
4663 if (banner)
4664 c_write_untrusted(ssh, banner, size);
4665 }
4666 crWaitUntilV(ispkt);
4667 }
4668 if (ssh->pktin.type == SSH2_MSG_USERAUTH_SUCCESS) {
4669 logevent("Access granted");
4670 s->we_are_in = TRUE;
4671 break;
4672 }
4673
4674 if (s->kbd_inter_running &&
4675 ssh->pktin.type == SSH2_MSG_USERAUTH_INFO_REQUEST) {
4676 /*
4677 * This is either a further set-of-prompts packet
4678 * in keyboard-interactive authentication, or it's
4679 * the same one and we came back here with `gotit'
4680 * set. In the former case, we must reset the
4681 * curr_prompt variable.
4682 */
4683 if (!s->gotit)
4684 s->curr_prompt = 0;
4685 } else if (ssh->pktin.type != SSH2_MSG_USERAUTH_FAILURE) {
4686 bombout(("Strange packet received during authentication: type %d",
4687 ssh->pktin.type));
4688 crStopV;
4689 }
4690
4691 s->gotit = FALSE;
4692
4693 /*
4694 * OK, we're now sitting on a USERAUTH_FAILURE message, so
4695 * we can look at the string in it and know what we can
4696 * helpfully try next.
4697 */
4698 if (ssh->pktin.type == SSH2_MSG_USERAUTH_FAILURE) {
4699 char *methods;
4700 int methlen;
4701 ssh2_pkt_getstring(ssh, &methods, &methlen);
4702 s->kbd_inter_running = FALSE;
4703 if (!ssh2_pkt_getbool(ssh)) {
4704 /*
4705 * We have received an unequivocal Access
4706 * Denied. This can translate to a variety of
4707 * messages:
4708 *
4709 * - if we'd just tried "none" authentication,
4710 * it's not worth printing anything at all
4711 *
4712 * - if we'd just tried a public key _offer_,
4713 * the message should be "Server refused our
4714 * key" (or no message at all if the key
4715 * came from Pageant)
4716 *
4717 * - if we'd just tried anything else, the
4718 * message really should be "Access denied".
4719 *
4720 * Additionally, if we'd just tried password
4721 * authentication, we should break out of this
4722 * whole loop so as to go back to the username
4723 * prompt.
4724 */
4725 if (s->type == AUTH_TYPE_NONE) {
4726 /* do nothing */
4727 } else if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD ||
4728 s->type == AUTH_TYPE_PUBLICKEY_OFFER_QUIET) {
4729 if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD)
4730 c_write_str(ssh, "Server refused our key\r\n");
4731 logevent("Server refused public key");
4732 } else if (s->type==AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET) {
4733 /* server declined keyboard-interactive; ignore */
4734 } else {
4735 c_write_str(ssh, "Access denied\r\n");
4736 logevent("Access denied");
4737 if (s->type == AUTH_TYPE_PASSWORD) {
4738 s->we_are_in = FALSE;
4739 break;
4740 }
4741 }
4742 } else {
4743 c_write_str(ssh, "Further authentication required\r\n");
4744 logevent("Further authentication required");
4745 }
4746
4747 s->can_pubkey =
4748 in_commasep_string("publickey", methods, methlen);
4749 s->can_passwd =
4750 in_commasep_string("password", methods, methlen);
4751 s->can_keyb_inter = ssh->cfg.try_ki_auth &&
4752 in_commasep_string("keyboard-interactive", methods, methlen);
4753 }
4754
4755 s->method = 0;
4756 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4757 s->need_pw = FALSE;
4758
4759 /*
4760 * Most password/passphrase prompts will be
4761 * non-echoing, so we set this to 0 by default.
4762 * Exception is that some keyboard-interactive prompts
4763 * can be echoing, in which case we'll set this to 1.
4764 */
4765 s->echo = 0;
4766
4767 if (!s->method && s->can_pubkey &&
4768 agent_exists() && !s->tried_agent) {
4769 /*
4770 * Attempt public-key authentication using Pageant.
4771 */
4772 void *r;
4773 s->authed = FALSE;
4774
4775 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4776 ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
4777
4778 s->tried_agent = TRUE;
4779
4780 logevent("Pageant is running. Requesting keys.");
4781
4782 /* Request the keys held by the agent. */
4783 PUT_32BIT(s->request, 1);
4784 s->request[4] = SSH2_AGENTC_REQUEST_IDENTITIES;
4785 if (!agent_query(s->request, 5, &r, &s->responselen,
4786 ssh_agent_callback, ssh)) {
4787 do {
4788 crReturnV;
4789 if (ispkt) {
4790 bombout(("Unexpected data from server while"
4791 " waiting for agent response"));
4792 crStopV;
4793 }
4794 } while (ispkt || inlen > 0);
4795 r = ssh->agent_response;
4796 s->responselen = ssh->agent_response_len;
4797 }
4798 s->response = (unsigned char *) r;
4799 if (s->response && s->responselen >= 5 &&
4800 s->response[4] == SSH2_AGENT_IDENTITIES_ANSWER) {
4801 s->p = s->response + 5;
4802 s->nkeys = GET_32BIT(s->p);
4803 s->p += 4;
4804 {
4805 char buf[64];
4806 sprintf(buf, "Pageant has %d SSH2 keys", s->nkeys);
4807 logevent(buf);
4808 }
4809 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
4810 void *vret;
4811
4812 {
4813 char buf[64];
4814 sprintf(buf, "Trying Pageant key #%d", s->keyi);
4815 logevent(buf);
4816 }
4817 s->pklen = GET_32BIT(s->p);
4818 s->p += 4;
4819 if (s->publickey_blob &&
4820 s->pklen == s->publickey_bloblen &&
4821 !memcmp(s->p, s->publickey_blob,
4822 s->publickey_bloblen)) {
4823 logevent("This key matches configured key file");
4824 s->tried_pubkey_config = 1;
4825 }
4826 s->pkblob = (char *)s->p;
4827 s->p += s->pklen;
4828 s->alglen = GET_32BIT(s->pkblob);
4829 s->alg = s->pkblob + 4;
4830 s->commentlen = GET_32BIT(s->p);
4831 s->p += 4;
4832 s->commentp = (char *)s->p;
4833 s->p += s->commentlen;
4834 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4835 ssh2_pkt_addstring(ssh, s->username);
4836 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4837 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4838 ssh2_pkt_addbool(ssh, FALSE); /* no signature included */
4839 ssh2_pkt_addstring_start(ssh);
4840 ssh2_pkt_addstring_data(ssh, s->alg, s->alglen);
4841 ssh2_pkt_addstring_start(ssh);
4842 ssh2_pkt_addstring_data(ssh, s->pkblob, s->pklen);
4843 ssh2_pkt_send(ssh);
4844
4845 crWaitUntilV(ispkt);
4846 if (ssh->pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
4847 logevent("Key refused");
4848 continue;
4849 }
4850
4851 if (flags & FLAG_VERBOSE) {
4852 c_write_str(ssh, "Authenticating with "
4853 "public key \"");
4854 c_write(ssh, s->commentp, s->commentlen);
4855 c_write_str(ssh, "\" from agent\r\n");
4856 }
4857
4858 /*
4859 * Server is willing to accept the key.
4860 * Construct a SIGN_REQUEST.
4861 */
4862 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4863 ssh2_pkt_addstring(ssh, s->username);
4864 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4865 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4866 ssh2_pkt_addbool(ssh, TRUE);
4867 ssh2_pkt_addstring_start(ssh);
4868 ssh2_pkt_addstring_data(ssh, s->alg, s->alglen);
4869 ssh2_pkt_addstring_start(ssh);
4870 ssh2_pkt_addstring_data(ssh, s->pkblob, s->pklen);
4871
4872 s->siglen = ssh->pktout.length - 5 + 4 + 20;
4873 if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
4874 s->siglen -= 4;
4875 s->len = 1; /* message type */
4876 s->len += 4 + s->pklen; /* key blob */
4877 s->len += 4 + s->siglen; /* data to sign */
4878 s->len += 4; /* flags */
4879 s->agentreq = snewn(4 + s->len, char);
4880 PUT_32BIT(s->agentreq, s->len);
4881 s->q = s->agentreq + 4;
4882 *s->q++ = SSH2_AGENTC_SIGN_REQUEST;
4883 PUT_32BIT(s->q, s->pklen);
4884 s->q += 4;
4885 memcpy(s->q, s->pkblob, s->pklen);
4886 s->q += s->pklen;
4887 PUT_32BIT(s->q, s->siglen);
4888 s->q += 4;
4889 /* Now the data to be signed... */
4890 if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
4891 PUT_32BIT(s->q, 20);
4892 s->q += 4;
4893 }
4894 memcpy(s->q, ssh->v2_session_id, 20);
4895 s->q += 20;
4896 memcpy(s->q, ssh->pktout.data + 5,
4897 ssh->pktout.length - 5);
4898 s->q += ssh->pktout.length - 5;
4899 /* And finally the (zero) flags word. */
4900 PUT_32BIT(s->q, 0);
4901 if (!agent_query(s->agentreq, s->len + 4,
4902 &vret, &s->retlen,
4903 ssh_agent_callback, ssh)) {
4904 do {
4905 crReturnV;
4906 if (ispkt) {
4907 bombout(("Unexpected data from server"
4908 " while waiting for agent"
4909 " response"));
4910 crStopV;
4911 }
4912 } while (ispkt || inlen > 0);
4913 vret = ssh->agent_response;
4914 s->retlen = ssh->agent_response_len;
4915 }
4916 s->ret = vret;
4917 sfree(s->agentreq);
4918 if (s->ret) {
4919 if (s->ret[4] == SSH2_AGENT_SIGN_RESPONSE) {
4920 logevent("Sending Pageant's response");
4921 ssh2_add_sigblob(ssh, s->pkblob, s->pklen,
4922 s->ret + 9,
4923 GET_32BIT(s->ret + 5));
4924 ssh2_pkt_send(ssh);
4925 s->authed = TRUE;
4926 break;
4927 } else {
4928 logevent
4929 ("Pageant failed to answer challenge");
4930 sfree(s->ret);
4931 }
4932 }
4933 }
4934 if (s->authed)
4935 continue;
4936 }
4937 sfree(s->response);
4938 }
4939
4940 if (!s->method && s->can_pubkey && s->publickey_blob
4941 && !s->tried_pubkey_config) {
4942 unsigned char *pub_blob;
4943 char *algorithm, *comment;
4944 int pub_blob_len;
4945
4946 s->tried_pubkey_config = TRUE;
4947
4948 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4949 ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
4950
4951 /*
4952 * Try the public key supplied in the configuration.
4953 *
4954 * First, offer the public blob to see if the server is
4955 * willing to accept it.
4956 */
4957 pub_blob =
4958 (unsigned char *)ssh2_userkey_loadpub(&ssh->cfg.keyfile,
4959 &algorithm,
4960 &pub_blob_len,
4961 NULL);
4962 if (pub_blob) {
4963 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4964 ssh2_pkt_addstring(ssh, s->username);
4965 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4966 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4967 ssh2_pkt_addbool(ssh, FALSE); /* no signature included */
4968 ssh2_pkt_addstring(ssh, algorithm);
4969 ssh2_pkt_addstring_start(ssh);
4970 ssh2_pkt_addstring_data(ssh, (char *)pub_blob,
4971 pub_blob_len);
4972 ssh2_pkt_send(ssh);
4973 logevent("Offered public key"); /* FIXME */
4974
4975 crWaitUntilV(ispkt);
4976 if (ssh->pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
4977 s->gotit = TRUE;
4978 s->type = AUTH_TYPE_PUBLICKEY_OFFER_LOUD;
4979 continue; /* key refused; give up on it */
4980 }
4981
4982 logevent("Offer of public key accepted");
4983 /*
4984 * Actually attempt a serious authentication using
4985 * the key.
4986 */
4987 if (ssh2_userkey_encrypted(&ssh->cfg.keyfile, &comment)) {
4988 sprintf(s->pwprompt,
4989 "Passphrase for key \"%.100s\": ",
4990 comment);
4991 s->need_pw = TRUE;
4992 } else {
4993 s->need_pw = FALSE;
4994 }
4995 if (flags & FLAG_VERBOSE) {
4996 c_write_str(ssh, "Authenticating with public key \"");
4997 c_write_str(ssh, comment);
4998 c_write_str(ssh, "\"\r\n");
4999 }
5000 s->method = AUTH_PUBLICKEY_FILE;
5001 }
5002 }
5003
5004 if (!s->method && s->can_keyb_inter && !s->tried_keyb_inter) {
5005 s->method = AUTH_KEYBOARD_INTERACTIVE;
5006 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
5007 s->tried_keyb_inter = TRUE;
5008
5009 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
5010 ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;
5011
5012 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
5013 ssh2_pkt_addstring(ssh, s->username);
5014 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
5015 ssh2_pkt_addstring(ssh, "keyboard-interactive"); /* method */
5016 ssh2_pkt_addstring(ssh, ""); /* lang */
5017 ssh2_pkt_addstring(ssh, "");
5018 ssh2_pkt_send(ssh);
5019
5020 crWaitUntilV(ispkt);
5021 if (ssh->pktin.type != SSH2_MSG_USERAUTH_INFO_REQUEST) {
5022 if (ssh->pktin.type == SSH2_MSG_USERAUTH_FAILURE)
5023 s->gotit = TRUE;
5024 logevent("Keyboard-interactive authentication refused");
5025 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET;
5026 continue;
5027 }
5028
5029 s->kbd_inter_running = TRUE;
5030 s->curr_prompt = 0;
5031 }
5032
5033 if (s->kbd_inter_running) {
5034 s->method = AUTH_KEYBOARD_INTERACTIVE;
5035 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
5036 s->tried_keyb_inter = TRUE;
5037
5038 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
5039 ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;
5040
5041 if (s->curr_prompt == 0) {
5042 /*
5043 * We've got a fresh USERAUTH_INFO_REQUEST.
5044 * Display header data, and start going through
5045 * the prompts.
5046 */
5047 char *name, *inst, *lang;
5048 int name_len, inst_len, lang_len;
5049
5050 ssh2_pkt_getstring(ssh, &name, &name_len);
5051 ssh2_pkt_getstring(ssh, &inst, &inst_len);
5052 ssh2_pkt_getstring(ssh, &lang, &lang_len);
5053 if (name_len > 0) {
5054 c_write_untrusted(ssh, name, name_len);
5055 c_write_str(ssh, "\r\n");
5056 }
5057 if (inst_len > 0) {
5058 c_write_untrusted(ssh, inst, inst_len);
5059 c_write_str(ssh, "\r\n");
5060 }
5061 s->num_prompts = ssh2_pkt_getuint32(ssh);
5062 }
5063
5064 /*
5065 * If there are prompts remaining in the packet,
5066 * display one and get a response.
5067 */
5068 if (s->curr_prompt < s->num_prompts) {
5069 char *prompt;
5070 int prompt_len;
5071
5072 ssh2_pkt_getstring(ssh, &prompt, &prompt_len);
5073 if (prompt_len > 0) {
5074 strncpy(s->pwprompt, prompt, sizeof(s->pwprompt));
5075 s->pwprompt[prompt_len < sizeof(s->pwprompt) ?
5076 prompt_len : sizeof(s->pwprompt)-1] = '\0';
5077 } else {
5078 strcpy(s->pwprompt,
5079 "<server failed to send prompt>: ");
5080 }
5081 s->echo = ssh2_pkt_getbool(ssh);
5082 s->need_pw = TRUE;
5083 } else
5084 s->need_pw = FALSE;
5085 }
5086
5087 if (!s->method && s->can_passwd) {
5088 s->method = AUTH_PASSWORD;
5089 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
5090 ssh->pkt_ctx |= SSH2_PKTCTX_PASSWORD;
5091 sprintf(s->pwprompt, "%.90s@%.90s's password: ", s->username,
5092 ssh->savedhost);
5093 s->need_pw = TRUE;
5094 }
5095
5096 if (s->need_pw) {
5097 if (ssh_get_line) {
5098 if (!ssh_get_line(s->pwprompt, s->password,
5099 sizeof(s->password), TRUE)) {
5100 /*
5101 * get_line failed to get a password (for
5102 * example because one was supplied on the
5103 * command line which has already failed to
5104 * work). Terminate.
5105 */
5106 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5107 ssh2_pkt_adduint32(ssh,SSH2_DISCONNECT_BY_APPLICATION);
5108 ssh2_pkt_addstring(ssh, "No more passwords available"
5109 " to try");
5110 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5111 ssh2_pkt_send(ssh);
5112 logevent("Unable to authenticate");
5113 connection_fatal(ssh->frontend,
5114 "Unable to authenticate");
5115 ssh_closing((Plug)ssh, NULL, 0, 0);
5116 crStopV;
5117 }
5118 } else {
5119 int ret; /* need not be saved across crReturn */
5120 c_write_untrusted(ssh, s->pwprompt, strlen(s->pwprompt));
5121 ssh->send_ok = 1;
5122
5123 setup_userpass_input(ssh, s->password,
5124 sizeof(s->password), s->echo);
5125 do {
5126 crWaitUntilV(!ispkt);
5127 ret = process_userpass_input(ssh, in, inlen);
5128 } while (ret == 0);
5129 if (ret < 0)
5130 cleanup_exit(0);
5131 c_write_str(ssh, "\r\n");
5132 }
5133 }
5134
5135 if (s->method == AUTH_PUBLICKEY_FILE) {
5136 /*
5137 * We have our passphrase. Now try the actual authentication.
5138 */
5139 struct ssh2_userkey *key;
5140 const char *error = NULL;
5141
5142 key = ssh2_load_userkey(&ssh->cfg.keyfile, s->password,
5143 &error);
5144 if (key == SSH2_WRONG_PASSPHRASE || key == NULL) {
5145 if (key == SSH2_WRONG_PASSPHRASE) {
5146 c_write_str(ssh, "Wrong passphrase\r\n");
5147 s->tried_pubkey_config = FALSE;
5148 } else {
5149 c_write_str(ssh, "Unable to load private key (");
5150 c_write_str(ssh, error);
5151 c_write_str(ssh, ")\r\n");
5152 s->tried_pubkey_config = TRUE;
5153 }
5154 /* Send a spurious AUTH_NONE to return to the top. */
5155 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
5156 ssh2_pkt_addstring(ssh, s->username);
5157 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
5158 ssh2_pkt_addstring(ssh, "none"); /* method */
5159 ssh2_pkt_send(ssh);
5160 s->type = AUTH_TYPE_NONE;
5161 } else {
5162 unsigned char *pkblob, *sigblob, *sigdata;
5163 int pkblob_len, sigblob_len, sigdata_len;
5164 int p;
5165
5166 /*
5167 * We have loaded the private key and the server
5168 * has announced that it's willing to accept it.
5169 * Hallelujah. Generate a signature and send it.
5170 */
5171 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
5172 ssh2_pkt_addstring(ssh, s->username);
5173 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
5174 ssh2_pkt_addstring(ssh, "publickey"); /* method */
5175 ssh2_pkt_addbool(ssh, TRUE);
5176 ssh2_pkt_addstring(ssh, key->alg->name);
5177 pkblob = key->alg->public_blob(key->data, &pkblob_len);
5178 ssh2_pkt_addstring_start(ssh);
5179 ssh2_pkt_addstring_data(ssh, (char *)pkblob, pkblob_len);
5180
5181 /*
5182 * The data to be signed is:
5183 *
5184 * string session-id
5185 *
5186 * followed by everything so far placed in the
5187 * outgoing packet.
5188 */
5189 sigdata_len = ssh->pktout.length - 5 + 4 + 20;
5190 if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
5191 sigdata_len -= 4;
5192 sigdata = snewn(sigdata_len, unsigned char);
5193 p = 0;
5194 if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
5195 PUT_32BIT(sigdata+p, 20);
5196 p += 4;
5197 }
5198 memcpy(sigdata+p, ssh->v2_session_id, 20); p += 20;
5199 memcpy(sigdata+p, ssh->pktout.data + 5,
5200 ssh->pktout.length - 5);
5201 p += ssh->pktout.length - 5;
5202 assert(p == sigdata_len);
5203 sigblob = key->alg->sign(key->data, (char *)sigdata,
5204 sigdata_len, &sigblob_len);
5205 ssh2_add_sigblob(ssh, pkblob, pkblob_len,
5206 sigblob, sigblob_len);
5207 sfree(pkblob);
5208 sfree(sigblob);
5209 sfree(sigdata);
5210
5211 ssh2_pkt_send(ssh);
5212 s->type = AUTH_TYPE_PUBLICKEY;
5213 key->alg->freekey(key->data);
5214 }
5215 } else if (s->method == AUTH_PASSWORD) {
5216 /*
5217 * We send the password packet lumped tightly together with
5218 * an SSH_MSG_IGNORE packet. The IGNORE packet contains a
5219 * string long enough to make the total length of the two
5220 * packets constant. This should ensure that a passive
5221 * listener doing traffic analyis can't work out the length
5222 * of the password.
5223 *
5224 * For this to work, we need an assumption about the
5225 * maximum length of the password packet. I think 256 is
5226 * pretty conservative. Anyone using a password longer than
5227 * that probably doesn't have much to worry about from
5228 * people who find out how long their password is!
5229 */
5230 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
5231 ssh2_pkt_addstring(ssh, s->username);
5232 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
5233 ssh2_pkt_addstring(ssh, "password");
5234 ssh2_pkt_addbool(ssh, FALSE);
5235 ssh2_pkt_addstring(ssh, s->password);
5236 memset(s->password, 0, sizeof(s->password));
5237 ssh2_pkt_defer(ssh);
5238 /*
5239 * We'll include a string that's an exact multiple of the
5240 * cipher block size. If the cipher is NULL for some
5241 * reason, we don't do this trick at all because we gain
5242 * nothing by it.
5243 */
5244 if (ssh->cscipher) {
5245 int stringlen, i;
5246
5247 stringlen = (256 - ssh->deferred_len);
5248 stringlen += ssh->cscipher->blksize - 1;
5249 stringlen -= (stringlen % ssh->cscipher->blksize);
5250 if (ssh->cscomp) {
5251 /*
5252 * Temporarily disable actual compression,
5253 * so we can guarantee to get this string
5254 * exactly the length we want it. The
5255 * compression-disabling routine should
5256 * return an integer indicating how many
5257 * bytes we should adjust our string length
5258 * by.
5259 */
5260 stringlen -=
5261 ssh->cscomp->disable_compression(ssh->cs_comp_ctx);
5262 }
5263 ssh2_pkt_init(ssh, SSH2_MSG_IGNORE);
5264 ssh2_pkt_addstring_start(ssh);
5265 for (i = 0; i < stringlen; i++) {
5266 char c = (char) random_byte();
5267 ssh2_pkt_addstring_data(ssh, &c, 1);
5268 }
5269 ssh2_pkt_defer(ssh);
5270 }
5271 ssh_pkt_defersend(ssh);
5272 logevent("Sent password");
5273 s->type = AUTH_TYPE_PASSWORD;
5274 } else if (s->method == AUTH_KEYBOARD_INTERACTIVE) {
5275 if (s->curr_prompt == 0) {
5276 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_INFO_RESPONSE);
5277 ssh2_pkt_adduint32(ssh, s->num_prompts);
5278 }
5279 if (s->need_pw) { /* only add pw if we just got one! */
5280 ssh2_pkt_addstring(ssh, s->password);
5281 memset(s->password, 0, sizeof(s->password));
5282 s->curr_prompt++;
5283 }
5284 if (s->curr_prompt >= s->num_prompts) {
5285 ssh2_pkt_send(ssh);
5286 } else {
5287 /*
5288 * If there are prompts remaining, we set
5289 * `gotit' so that we won't attempt to get
5290 * another packet. Then we go back round the
5291 * loop and will end up retrieving another
5292 * prompt out of the existing packet. Funky or
5293 * what?
5294 */
5295 s->gotit = TRUE;
5296 }
5297 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
5298 } else {
5299 c_write_str(ssh, "No supported authentication methods"
5300 " left to try!\r\n");
5301 logevent("No supported authentications offered."
5302 " Disconnecting");
5303 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5304 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5305 ssh2_pkt_addstring(ssh, "No supported authentication"
5306 " methods available");
5307 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5308 ssh2_pkt_send(ssh);
5309 ssh_closing((Plug)ssh, NULL, 0, 0);
5310 crStopV;
5311 }
5312 }
5313 } while (!s->we_are_in);
5314
5315 /*
5316 * Now we're authenticated for the connection protocol. The
5317 * connection protocol will automatically have started at this
5318 * point; there's no need to send SERVICE_REQUEST.
5319 */
5320
5321 /*
5322 * So now create a channel with a session in it.
5323 */
5324 ssh->channels = newtree234(ssh_channelcmp);
5325 ssh->mainchan = snew(struct ssh_channel);
5326 ssh->mainchan->ssh = ssh;
5327 ssh->mainchan->localid = alloc_channel_id(ssh);
5328 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN);
5329 ssh2_pkt_addstring(ssh, "session");
5330 ssh2_pkt_adduint32(ssh, ssh->mainchan->localid);
5331 ssh->mainchan->v.v2.locwindow = OUR_V2_WINSIZE;
5332 ssh2_pkt_adduint32(ssh, ssh->mainchan->v.v2.locwindow);/* our window size */
5333 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
5334 ssh2_pkt_send(ssh);
5335 crWaitUntilV(ispkt);
5336 if (ssh->pktin.type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
5337 bombout(("Server refused to open a session"));
5338 crStopV;
5339 /* FIXME: error data comes back in FAILURE packet */
5340 }
5341 if (ssh2_pkt_getuint32(ssh) != ssh->mainchan->localid) {
5342 bombout(("Server's channel confirmation cited wrong channel"));
5343 crStopV;
5344 }
5345 ssh->mainchan->remoteid = ssh2_pkt_getuint32(ssh);
5346 ssh->mainchan->type = CHAN_MAINSESSION;
5347 ssh->mainchan->closes = 0;
5348 ssh->mainchan->v.v2.remwindow = ssh2_pkt_getuint32(ssh);
5349 ssh->mainchan->v.v2.remmaxpkt = ssh2_pkt_getuint32(ssh);
5350 bufchain_init(&ssh->mainchan->v.v2.outbuffer);
5351 add234(ssh->channels, ssh->mainchan);
5352 logevent("Opened channel for session");
5353
5354 /*
5355 * Potentially enable X11 forwarding.
5356 */
5357 if (ssh->cfg.x11_forward) {
5358 char proto[20], data[64];
5359 logevent("Requesting X11 forwarding");
5360 ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
5361 data, sizeof(data), ssh->cfg.x11_auth);
5362 x11_get_real_auth(ssh->x11auth, ssh->cfg.x11_display);
5363 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5364 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
5365 ssh2_pkt_addstring(ssh, "x11-req");
5366 ssh2_pkt_addbool(ssh, 1); /* want reply */
5367 ssh2_pkt_addbool(ssh, 0); /* many connections */
5368 ssh2_pkt_addstring(ssh, proto);
5369 ssh2_pkt_addstring(ssh, data);
5370 ssh2_pkt_adduint32(ssh, x11_get_screen_number(ssh->cfg.x11_display));
5371 ssh2_pkt_send(ssh);
5372
5373 do {
5374 crWaitUntilV(ispkt);
5375 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5376 unsigned i = ssh2_pkt_getuint32(ssh);
5377 struct ssh_channel *c;
5378 c = find234(ssh->channels, &i, ssh_channelfind);
5379 if (!c)
5380 continue; /* nonexistent channel */
5381 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5382 }
5383 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5384
5385 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5386 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5387 bombout(("Unexpected response to X11 forwarding request:"
5388 " packet type %d", ssh->pktin.type));
5389 crStopV;
5390 }
5391 logevent("X11 forwarding refused");
5392 } else {
5393 logevent("X11 forwarding enabled");
5394 ssh->X11_fwd_enabled = TRUE;
5395 }
5396 }
5397
5398 /*
5399 * Enable port forwardings.
5400 */
5401 {
5402 char type;
5403 int n;
5404 int sport,dport,sserv,dserv;
5405 char sports[256], dports[256], saddr[256], host[256];
5406
5407 ssh->rportfwds = newtree234(ssh_rportcmp_ssh2);
5408 /* Add port forwardings. */
5409 ssh->portfwd_strptr = ssh->cfg.portfwd;
5410 while (*ssh->portfwd_strptr) {
5411 type = *ssh->portfwd_strptr++;
5412 saddr[0] = '\0';
5413 n = 0;
5414 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != '\t') {
5415 if (*ssh->portfwd_strptr == ':') {
5416 /*
5417 * We've seen a colon in the middle of the
5418 * source port number. This means that
5419 * everything we've seen until now is the
5420 * source _address_, so we'll move it into
5421 * saddr and start sports from the beginning
5422 * again.
5423 */
5424 ssh->portfwd_strptr++;
5425 sports[n] = '\0';
5426 strcpy(saddr, sports);
5427 n = 0;
5428 }
5429 if (n < 255) sports[n++] = *ssh->portfwd_strptr++;
5430 }
5431 sports[n] = 0;
5432 if (type != 'D') {
5433 if (*ssh->portfwd_strptr == '\t')
5434 ssh->portfwd_strptr++;
5435 n = 0;
5436 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':') {
5437 if (n < 255) host[n++] = *ssh->portfwd_strptr++;
5438 }
5439 host[n] = 0;
5440 if (*ssh->portfwd_strptr == ':')
5441 ssh->portfwd_strptr++;
5442 n = 0;
5443 while (*ssh->portfwd_strptr) {
5444 if (n < 255) dports[n++] = *ssh->portfwd_strptr++;
5445 }
5446 dports[n] = 0;
5447 ssh->portfwd_strptr++;
5448 dport = atoi(dports);
5449 dserv = 0;
5450 if (dport == 0) {
5451 dserv = 1;
5452 dport = net_service_lookup(dports);
5453 if (!dport) {
5454 logeventf(ssh, "Service lookup failed for destination"
5455 " port \"%s\"", dports);
5456 }
5457 }
5458 } else {
5459 while (*ssh->portfwd_strptr) ssh->portfwd_strptr++;
5460 dport = dserv = -1;
5461 ssh->portfwd_strptr++; /* eat the NUL and move to next one */
5462 }
5463 sport = atoi(sports);
5464 sserv = 0;
5465 if (sport == 0) {
5466 sserv = 1;
5467 sport = net_service_lookup(sports);
5468 if (!sport) {
5469 logeventf(ssh, "Service lookup failed for source"
5470 " port \"%s\"", sports);
5471 }
5472 }
5473 if (sport && dport) {
5474 if (type == 'L') {
5475 pfd_addforward(host, dport, *saddr ? saddr : NULL,
5476 sport, ssh, &ssh->cfg);
5477 logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
5478 " forwarding to %s:%.*s%.*s%d%.*s",
5479 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
5480 (int)(*saddr?1:0), ":",
5481 (int)(sserv ? strlen(sports) : 0), sports,
5482 sserv, "(", sport, sserv, ")",
5483 host,
5484 (int)(dserv ? strlen(dports) : 0), dports,
5485 dserv, "(", dport, dserv, ")");
5486 } else if (type == 'D') {
5487 pfd_addforward(NULL, -1, *saddr ? saddr : NULL,
5488 sport, ssh, &ssh->cfg);
5489 logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
5490 " doing SOCKS dynamic forwarding",
5491 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
5492 (int)(*saddr?1:0), ":",
5493 (int)(sserv ? strlen(sports) : 0), sports,
5494 sserv, "(", sport, sserv, ")");
5495 } else {
5496 struct ssh_rportfwd *pf;
5497 pf = snew(struct ssh_rportfwd);
5498 strcpy(pf->dhost, host);
5499 pf->dport = dport;
5500 pf->sport = sport;
5501 if (add234(ssh->rportfwds, pf) != pf) {
5502 logeventf(ssh, "Duplicate remote port forwarding"
5503 " to %s:%d", host, dport);
5504 sfree(pf);
5505 } else {
5506 logeventf(ssh, "Requesting remote port "
5507 "%.*s%.*s%.*s%.*s%d%.*s"
5508 " forward to %s:%.*s%.*s%d%.*s",
5509 (int)(*saddr?strlen(saddr):0),
5510 *saddr?saddr:NULL,
5511 (int)(*saddr?1:0), ":",
5512 (int)(sserv ? strlen(sports) : 0), sports,
5513 sserv, "(", sport, sserv, ")",
5514 host,
5515 (int)(dserv ? strlen(dports) : 0), dports,
5516 dserv, "(", dport, dserv, ")");
5517 ssh2_pkt_init(ssh, SSH2_MSG_GLOBAL_REQUEST);
5518 ssh2_pkt_addstring(ssh, "tcpip-forward");
5519 ssh2_pkt_addbool(ssh, 1);/* want reply */
5520 if (*saddr)
5521 ssh2_pkt_addstring(ssh, saddr);
5522 if (ssh->cfg.rport_acceptall)
5523 ssh2_pkt_addstring(ssh, "0.0.0.0");
5524 else
5525 ssh2_pkt_addstring(ssh, "127.0.0.1");
5526 ssh2_pkt_adduint32(ssh, sport);
5527 ssh2_pkt_send(ssh);
5528
5529 do {
5530 crWaitUntilV(ispkt);
5531 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5532 unsigned i = ssh2_pkt_getuint32(ssh);
5533 struct ssh_channel *c;
5534 c = find234(ssh->channels, &i, ssh_channelfind);
5535 if (!c)
5536 continue;/* nonexistent channel */
5537 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5538 }
5539 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5540
5541 if (ssh->pktin.type != SSH2_MSG_REQUEST_SUCCESS) {
5542 if (ssh->pktin.type != SSH2_MSG_REQUEST_FAILURE) {
5543 bombout(("Unexpected response to port "
5544 "forwarding request: packet type %d",
5545 ssh->pktin.type));
5546 crStopV;
5547 }
5548 logevent("Server refused this port forwarding");
5549 } else {
5550 logevent("Remote port forwarding enabled");
5551 }
5552 }
5553 }
5554 }
5555 }
5556 }
5557
5558 /*
5559 * Potentially enable agent forwarding.
5560 */
5561 if (ssh->cfg.agentfwd && agent_exists()) {
5562 logevent("Requesting OpenSSH-style agent forwarding");
5563 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5564 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
5565 ssh2_pkt_addstring(ssh, "auth-agent-req@openssh.com");
5566 ssh2_pkt_addbool(ssh, 1); /* want reply */
5567 ssh2_pkt_send(ssh);
5568
5569 do {
5570 crWaitUntilV(ispkt);
5571 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5572 unsigned i = ssh2_pkt_getuint32(ssh);
5573 struct ssh_channel *c;
5574 c = find234(ssh->channels, &i, ssh_channelfind);
5575 if (!c)
5576 continue; /* nonexistent channel */
5577 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5578 }
5579 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5580
5581 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5582 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5583 bombout(("Unexpected response to agent forwarding request:"
5584 " packet type %d", ssh->pktin.type));
5585 crStopV;
5586 }
5587 logevent("Agent forwarding refused");
5588 } else {
5589 logevent("Agent forwarding enabled");
5590 ssh->agentfwd_enabled = TRUE;
5591 }
5592 }
5593
5594 /*
5595 * Now allocate a pty for the session.
5596 */
5597 if (!ssh->cfg.nopty) {
5598 /* Unpick the terminal-speed string. */
5599 /* XXX perhaps we should allow no speeds to be sent. */
5600 ssh->ospeed = 38400; ssh->ispeed = 38400; /* last-resort defaults */
5601 sscanf(ssh->cfg.termspeed, "%d,%d", &ssh->ospeed, &ssh->ispeed);
5602 /* Build the pty request. */
5603 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5604 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid); /* recipient channel */
5605 ssh2_pkt_addstring(ssh, "pty-req");
5606 ssh2_pkt_addbool(ssh, 1); /* want reply */
5607 ssh2_pkt_addstring(ssh, ssh->cfg.termtype);
5608 ssh2_pkt_adduint32(ssh, ssh->term_width);
5609 ssh2_pkt_adduint32(ssh, ssh->term_height);
5610 ssh2_pkt_adduint32(ssh, 0); /* pixel width */
5611 ssh2_pkt_adduint32(ssh, 0); /* pixel height */
5612 ssh2_pkt_addstring_start(ssh);
5613 ssh2_pkt_addbyte(ssh, 128); /* TTY_OP_ISPEED */
5614 ssh2_pkt_adduint32(ssh, ssh->ispeed);
5615 ssh2_pkt_addbyte(ssh, 129); /* TTY_OP_OSPEED */
5616 ssh2_pkt_adduint32(ssh, ssh->ospeed);
5617 ssh2_pkt_addstring_data(ssh, "\0", 1); /* TTY_OP_END */
5618 ssh2_pkt_send(ssh);
5619 ssh->state = SSH_STATE_INTERMED;
5620
5621 do {
5622 crWaitUntilV(ispkt);
5623 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5624 unsigned i = ssh2_pkt_getuint32(ssh);
5625 struct ssh_channel *c;
5626 c = find234(ssh->channels, &i, ssh_channelfind);
5627 if (!c)
5628 continue; /* nonexistent channel */
5629 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5630 }
5631 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5632
5633 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5634 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5635 bombout(("Unexpected response to pty request:"
5636 " packet type %d", ssh->pktin.type));
5637 crStopV;
5638 }
5639 c_write_str(ssh, "Server refused to allocate pty\r\n");
5640 ssh->editing = ssh->echoing = 1;
5641 } else {
5642 logeventf(ssh, "Allocated pty (ospeed %dbps, ispeed %dbps)",
5643 ssh->ospeed, ssh->ispeed);
5644 }
5645 } else {
5646 ssh->editing = ssh->echoing = 1;
5647 }
5648
5649 /*
5650 * Start a shell or a remote command. We may have to attempt
5651 * this twice if the config data has provided a second choice
5652 * of command.
5653 */
5654 while (1) {
5655 int subsys;
5656 char *cmd;
5657
5658 if (ssh->fallback_cmd) {
5659 subsys = ssh->cfg.ssh_subsys2;
5660 cmd = ssh->cfg.remote_cmd_ptr2;
5661 } else {
5662 subsys = ssh->cfg.ssh_subsys;
5663 cmd = ssh->cfg.remote_cmd_ptr;
5664 }
5665
5666 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5667 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid); /* recipient channel */
5668 if (subsys) {
5669 ssh2_pkt_addstring(ssh, "subsystem");
5670 ssh2_pkt_addbool(ssh, 1); /* want reply */
5671 ssh2_pkt_addstring(ssh, cmd);
5672 } else if (*cmd) {
5673 ssh2_pkt_addstring(ssh, "exec");
5674 ssh2_pkt_addbool(ssh, 1); /* want reply */
5675 ssh2_pkt_addstring(ssh, cmd);
5676 } else {
5677 ssh2_pkt_addstring(ssh, "shell");
5678 ssh2_pkt_addbool(ssh, 1); /* want reply */
5679 }
5680 ssh2_pkt_send(ssh);
5681 do {
5682 crWaitUntilV(ispkt);
5683 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5684 unsigned i = ssh2_pkt_getuint32(ssh);
5685 struct ssh_channel *c;
5686 c = find234(ssh->channels, &i, ssh_channelfind);
5687 if (!c)
5688 continue; /* nonexistent channel */
5689 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5690 }
5691 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5692 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5693 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5694 bombout(("Unexpected response to shell/command request:"
5695 " packet type %d", ssh->pktin.type));
5696 crStopV;
5697 }
5698 /*
5699 * We failed to start the command. If this is the
5700 * fallback command, we really are finished; if it's
5701 * not, and if the fallback command exists, try falling
5702 * back to it before complaining.
5703 */
5704 if (!ssh->fallback_cmd && ssh->cfg.remote_cmd_ptr2 != NULL) {
5705 logevent("Primary command failed; attempting fallback");
5706 ssh->fallback_cmd = TRUE;
5707 continue;
5708 }
5709 bombout(("Server refused to start a shell/command"));
5710 crStopV;
5711 } else {
5712 logevent("Started a shell/command");
5713 }
5714 break;
5715 }
5716
5717 ssh->state = SSH_STATE_SESSION;
5718 if (ssh->size_needed)
5719 ssh_size(ssh, ssh->term_width, ssh->term_height);
5720 if (ssh->eof_needed)
5721 ssh_special(ssh, TS_EOF);
5722
5723 /*
5724 * Transfer data!
5725 */
5726 if (ssh->ldisc)
5727 ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */
5728 ssh->send_ok = 1;
5729 while (1) {
5730 crReturnV;
5731 s->try_send = FALSE;
5732 if (ispkt) {
5733 if (ssh->pktin.type == SSH2_MSG_CHANNEL_DATA ||
5734 ssh->pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA) {
5735 char *data;
5736 int length;
5737 unsigned i = ssh2_pkt_getuint32(ssh);
5738 struct ssh_channel *c;
5739 c = find234(ssh->channels, &i, ssh_channelfind);
5740 if (!c)
5741 continue; /* nonexistent channel */
5742 if (ssh->pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
5743 ssh2_pkt_getuint32(ssh) != SSH2_EXTENDED_DATA_STDERR)
5744 continue; /* extended but not stderr */
5745 ssh2_pkt_getstring(ssh, &data, &length);
5746 if (data) {
5747 int bufsize = 0;
5748 c->v.v2.locwindow -= length;
5749 switch (c->type) {
5750 case CHAN_MAINSESSION:
5751 bufsize =
5752 from_backend(ssh->frontend, ssh->pktin.type ==
5753 SSH2_MSG_CHANNEL_EXTENDED_DATA,
5754 data, length);
5755 break;
5756 case CHAN_X11:
5757 bufsize = x11_send(c->u.x11.s, data, length);
5758 break;
5759 case CHAN_SOCKDATA:
5760 bufsize = pfd_send(c->u.pfd.s, data, length);
5761 break;
5762 case CHAN_AGENT:
5763 while (length > 0) {
5764 if (c->u.a.lensofar < 4) {
5765 int l = min(4 - c->u.a.lensofar, length);
5766 memcpy(c->u.a.msglen + c->u.a.lensofar,
5767 data, l);
5768 data += l;
5769 length -= l;
5770 c->u.a.lensofar += l;
5771 }
5772 if (c->u.a.lensofar == 4) {
5773 c->u.a.totallen =
5774 4 + GET_32BIT(c->u.a.msglen);
5775 c->u.a.message = snewn(c->u.a.totallen,
5776 unsigned char);
5777 memcpy(c->u.a.message, c->u.a.msglen, 4);
5778 }
5779 if (c->u.a.lensofar >= 4 && length > 0) {
5780 int l =
5781 min(c->u.a.totallen - c->u.a.lensofar,
5782 length);
5783 memcpy(c->u.a.message + c->u.a.lensofar,
5784 data, l);
5785 data += l;
5786 length -= l;
5787 c->u.a.lensofar += l;
5788 }
5789 if (c->u.a.lensofar == c->u.a.totallen) {
5790 void *reply;
5791 int replylen;
5792 if (agent_query(c->u.a.message,
5793 c->u.a.totallen,
5794 &reply, &replylen,
5795 ssh_agentf_callback, c))
5796 ssh_agentf_callback(c, reply, replylen);
5797 sfree(c->u.a.message);
5798 c->u.a.lensofar = 0;
5799 }
5800 }
5801 bufsize = 0;
5802 break;
5803 }
5804 /*
5805 * If we are not buffering too much data,
5806 * enlarge the window again at the remote side.
5807 */
5808 if (bufsize < OUR_V2_WINSIZE)
5809 ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
5810 }
5811 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_EOF) {
5812 unsigned i = ssh2_pkt_getuint32(ssh);
5813 struct ssh_channel *c;
5814
5815 c = find234(ssh->channels, &i, ssh_channelfind);
5816 if (!c)
5817 continue; /* nonexistent channel */
5818
5819 if (c->type == CHAN_X11) {
5820 /*
5821 * Remote EOF on an X11 channel means we should
5822 * wrap up and close the channel ourselves.
5823 */
5824 x11_close(c->u.x11.s);
5825 sshfwd_close(c);
5826 } else if (c->type == CHAN_AGENT) {
5827 sshfwd_close(c);
5828 } else if (c->type == CHAN_SOCKDATA) {
5829 pfd_close(c->u.pfd.s);
5830 sshfwd_close(c);
5831 }
5832 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_CLOSE) {
5833 unsigned i = ssh2_pkt_getuint32(ssh);
5834 struct ssh_channel *c;
5835
5836 c = find234(ssh->channels, &i, ssh_channelfind);
5837 if (!c || ((int)c->remoteid) == -1) {
5838 bombout(("Received CHANNEL_CLOSE for %s channel %d\n",
5839 c ? "half-open" : "nonexistent", i));
5840 crStopV;
5841 }
5842 /* Do pre-close processing on the channel. */
5843 switch (c->type) {
5844 case CHAN_MAINSESSION:
5845 break; /* nothing to see here, move along */
5846 case CHAN_X11:
5847 if (c->u.x11.s != NULL)
5848 x11_close(c->u.x11.s);
5849 sshfwd_close(c);
5850 break;
5851 case CHAN_AGENT:
5852 sshfwd_close(c);
5853 break;
5854 case CHAN_SOCKDATA:
5855 if (c->u.pfd.s != NULL)
5856 pfd_close(c->u.pfd.s);
5857 sshfwd_close(c);
5858 break;
5859 }
5860 if (c->closes == 0) {
5861 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
5862 ssh2_pkt_adduint32(ssh, c->remoteid);
5863 ssh2_pkt_send(ssh);
5864 }
5865 del234(ssh->channels, c);
5866 bufchain_clear(&c->v.v2.outbuffer);
5867 sfree(c);
5868
5869 /*
5870 * See if that was the last channel left open.
5871 */
5872 if (count234(ssh->channels) == 0) {
5873 logevent("All channels closed. Disconnecting");
5874 #if 0
5875 /*
5876 * We used to send SSH_MSG_DISCONNECT here,
5877 * because I'd believed that _every_ conforming
5878 * SSH2 connection had to end with a disconnect
5879 * being sent by at least one side; apparently
5880 * I was wrong and it's perfectly OK to
5881 * unceremoniously slam the connection shut
5882 * when you're done, and indeed OpenSSH feels
5883 * this is more polite than sending a
5884 * DISCONNECT. So now we don't.
5885 */
5886 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5887 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5888 ssh2_pkt_addstring(ssh, "All open channels closed");
5889 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5890 ssh2_pkt_send(ssh);
5891 #endif
5892 ssh_closing((Plug)ssh, NULL, 0, 0);
5893 crStopV;
5894 }
5895 continue; /* remote sends close; ignore (FIXME) */
5896 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5897 unsigned i = ssh2_pkt_getuint32(ssh);
5898 struct ssh_channel *c;
5899 c = find234(ssh->channels, &i, ssh_channelfind);
5900 if (!c || c->closes)
5901 continue; /* nonexistent or closing channel */
5902 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5903 s->try_send = TRUE;
5904 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
5905 unsigned i = ssh2_pkt_getuint32(ssh);
5906 struct ssh_channel *c;
5907 c = find234(ssh->channels, &i, ssh_channelfind);
5908 if (!c)
5909 continue; /* nonexistent channel */
5910 if (c->type != CHAN_SOCKDATA_DORMANT)
5911 continue; /* dunno why they're confirming this */
5912 c->remoteid = ssh2_pkt_getuint32(ssh);
5913 c->type = CHAN_SOCKDATA;
5914 c->v.v2.remwindow = ssh2_pkt_getuint32(ssh);
5915 c->v.v2.remmaxpkt = ssh2_pkt_getuint32(ssh);
5916 if (c->u.pfd.s)
5917 pfd_confirm(c->u.pfd.s);
5918 if (c->closes) {
5919 /*
5920 * We have a pending close on this channel,
5921 * which we decided on before the server acked
5922 * the channel open. So now we know the
5923 * remoteid, we can close it again.
5924 */
5925 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
5926 ssh2_pkt_adduint32(ssh, c->remoteid);
5927 ssh2_pkt_send(ssh);
5928 }
5929 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN_FAILURE) {
5930 unsigned i = ssh2_pkt_getuint32(ssh);
5931 struct ssh_channel *c;
5932 c = find234(ssh->channels, &i, ssh_channelfind);
5933 if (!c)
5934 continue; /* nonexistent channel */
5935 if (c->type != CHAN_SOCKDATA_DORMANT)
5936 continue; /* dunno why they're failing this */
5937
5938 logevent("Forwarded connection refused by server");
5939
5940 pfd_close(c->u.pfd.s);
5941
5942 del234(ssh->channels, c);
5943 sfree(c);
5944 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_REQUEST) {
5945 unsigned localid;
5946 char *type;
5947 int typelen, want_reply;
5948 struct ssh_channel *c;
5949
5950 localid = ssh2_pkt_getuint32(ssh);
5951 ssh2_pkt_getstring(ssh, &type, &typelen);
5952 want_reply = ssh2_pkt_getbool(ssh);
5953
5954 /*
5955 * First, check that the channel exists. Otherwise,
5956 * we can instantly disconnect with a rude message.
5957 */
5958 c = find234(ssh->channels, &localid, ssh_channelfind);
5959 if (!c) {
5960 char buf[80];
5961 sprintf(buf, "Received channel request for nonexistent"
5962 " channel %d", localid);
5963 logevent(buf);
5964 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5965 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5966 ssh2_pkt_addstring(ssh, buf);
5967 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5968 ssh2_pkt_send(ssh);
5969 connection_fatal(ssh->frontend, "%s", buf);
5970 ssh_closing((Plug)ssh, NULL, 0, 0);
5971 crStopV;
5972 }
5973
5974 /*
5975 * Having got the channel number, we now look at
5976 * the request type string to see if it's something
5977 * we recognise.
5978 */
5979 if (typelen == 11 && !memcmp(type, "exit-status", 11) &&
5980 c == ssh->mainchan) {
5981 /* We recognise "exit-status" on the primary channel. */
5982 char buf[100];
5983 ssh->exitcode = ssh2_pkt_getuint32(ssh);
5984 sprintf(buf, "Server sent command exit status %d",
5985 ssh->exitcode);
5986 logevent(buf);
5987 if (want_reply) {
5988 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_SUCCESS);
5989 ssh2_pkt_adduint32(ssh, c->remoteid);
5990 ssh2_pkt_send(ssh);
5991 }
5992 } else {
5993 /*
5994 * This is a channel request we don't know
5995 * about, so we now either ignore the request
5996 * or respond with CHANNEL_FAILURE, depending
5997 * on want_reply.
5998 */
5999 if (want_reply) {
6000 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_FAILURE);
6001 ssh2_pkt_adduint32(ssh, c->remoteid);
6002 ssh2_pkt_send(ssh);
6003 }
6004 }
6005 } else if (ssh->pktin.type == SSH2_MSG_GLOBAL_REQUEST) {
6006 char *type;
6007 int typelen, want_reply;
6008
6009 ssh2_pkt_getstring(ssh, &type, &typelen);
6010 want_reply = ssh2_pkt_getbool(ssh);
6011
6012 /*
6013 * We currently don't support any global requests
6014 * at all, so we either ignore the request or
6015 * respond with REQUEST_FAILURE, depending on
6016 * want_reply.
6017 */
6018 if (want_reply) {
6019 ssh2_pkt_init(ssh, SSH2_MSG_REQUEST_FAILURE);
6020 ssh2_pkt_send(ssh);
6021 }
6022 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN) {
6023 char *type;
6024 int typelen;
6025 char *peeraddr;
6026 int peeraddrlen;
6027 int peerport;
6028 char *error = NULL;
6029 struct ssh_channel *c;
6030 unsigned remid, winsize, pktsize;
6031 ssh2_pkt_getstring(ssh, &type, &typelen);
6032 c = snew(struct ssh_channel);
6033 c->ssh = ssh;
6034
6035 remid = ssh2_pkt_getuint32(ssh);
6036 winsize = ssh2_pkt_getuint32(ssh);
6037 pktsize = ssh2_pkt_getuint32(ssh);
6038
6039 if (typelen == 3 && !memcmp(type, "x11", 3)) {
6040 char *addrstr;
6041
6042 ssh2_pkt_getstring(ssh, &peeraddr, &peeraddrlen);
6043 addrstr = snewn(peeraddrlen+1, char);
6044 memcpy(addrstr, peeraddr, peeraddrlen);
6045 peeraddr[peeraddrlen] = '\0';
6046 peerport = ssh2_pkt_getuint32(ssh);
6047
6048 if (!ssh->X11_fwd_enabled)
6049 error = "X11 forwarding is not enabled";
6050 else if (x11_init(&c->u.x11.s, ssh->cfg.x11_display, c,
6051 ssh->x11auth, addrstr, peerport,
6052 &ssh->cfg) != NULL) {
6053 error = "Unable to open an X11 connection";
6054 } else {
6055 c->type = CHAN_X11;
6056 }
6057
6058 sfree(addrstr);
6059 } else if (typelen == 15 &&
6060 !memcmp(type, "forwarded-tcpip", 15)) {
6061 struct ssh_rportfwd pf, *realpf;
6062 char *dummy;
6063 int dummylen;
6064 ssh2_pkt_getstring(ssh, &dummy, &dummylen);/* skip address */
6065 pf.sport = ssh2_pkt_getuint32(ssh);
6066 ssh2_pkt_getstring(ssh, &peeraddr, &peeraddrlen);
6067 peerport = ssh2_pkt_getuint32(ssh);
6068 realpf = find234(ssh->rportfwds, &pf, NULL);
6069 if (realpf == NULL) {
6070 error = "Remote port is not recognised";
6071 } else {
6072 const char *e = pfd_newconnect(&c->u.pfd.s,
6073 realpf->dhost,
6074 realpf->dport, c,
6075 &ssh->cfg);
6076 logeventf(ssh, "Received remote port open request"
6077 " for %s:%d", realpf->dhost, realpf->dport);
6078 if (e != NULL) {
6079 logeventf(ssh, "Port open failed: %s", e);
6080 error = "Port open failed";
6081 } else {
6082 logevent("Forwarded port opened successfully");
6083 c->type = CHAN_SOCKDATA;
6084 }
6085 }
6086 } else if (typelen == 22 &&
6087 !memcmp(type, "auth-agent@openssh.com", 3)) {
6088 if (!ssh->agentfwd_enabled)
6089 error = "Agent forwarding is not enabled";
6090 else {
6091 c->type = CHAN_AGENT; /* identify channel type */
6092 c->u.a.lensofar = 0;
6093 }
6094 } else {
6095 error = "Unsupported channel type requested";
6096 }
6097
6098 c->remoteid = remid;
6099 if (error) {
6100 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN_FAILURE);
6101 ssh2_pkt_adduint32(ssh, c->remoteid);
6102 ssh2_pkt_adduint32(ssh, SSH2_OPEN_CONNECT_FAILED);
6103 ssh2_pkt_addstring(ssh, error);
6104 ssh2_pkt_addstring(ssh, "en"); /* language tag */
6105 ssh2_pkt_send(ssh);
6106 sfree(c);
6107 } else {
6108 c->localid = alloc_channel_id(ssh);
6109 c->closes = 0;
6110 c->v.v2.locwindow = OUR_V2_WINSIZE;
6111 c->v.v2.remwindow = winsize;
6112 c->v.v2.remmaxpkt = pktsize;
6113 bufchain_init(&c->v.v2.outbuffer);
6114 add234(ssh->channels, c);
6115 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
6116 ssh2_pkt_adduint32(ssh, c->remoteid);
6117 ssh2_pkt_adduint32(ssh, c->localid);
6118 ssh2_pkt_adduint32(ssh, c->v.v2.locwindow);
6119 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
6120 ssh2_pkt_send(ssh);
6121 }
6122 } else {
6123 bombout(("Strange packet received: type %d", ssh->pktin.type));
6124 crStopV;
6125 }
6126 } else {
6127 /*
6128 * We have spare data. Add it to the channel buffer.
6129 */
6130 ssh2_add_channel_data(ssh->mainchan, (char *)in, inlen);
6131 s->try_send = TRUE;
6132 }
6133 if (s->try_send) {
6134 int i;
6135 struct ssh_channel *c;
6136 /*
6137 * Try to send data on all channels if we can.
6138 */
6139 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
6140 int bufsize;
6141 if (c->closes)
6142 continue; /* don't send on closing channels */
6143 bufsize = ssh2_try_send(c);
6144 if (bufsize == 0) {
6145 switch (c->type) {
6146 case CHAN_MAINSESSION:
6147 /* stdin need not receive an unthrottle
6148 * notification since it will be polled */
6149 break;
6150 case CHAN_X11:
6151 x11_unthrottle(c->u.x11.s);
6152 break;
6153 case CHAN_AGENT:
6154 /* agent sockets are request/response and need no
6155 * buffer management */
6156 break;
6157 case CHAN_SOCKDATA:
6158 pfd_unthrottle(c->u.pfd.s);
6159 break;
6160 }
6161 }
6162 }
6163 }
6164 }
6165
6166 crFinishV;
6167 }
6168
6169 /*
6170 * Handle the top-level SSH2 protocol.
6171 */
6172 static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
6173 {
6174 if (do_ssh2_transport(ssh, in, inlen, ispkt) == 0)
6175 return;
6176 do_ssh2_authconn(ssh, in, inlen, ispkt);
6177 }
6178
6179 /*
6180 * Called to set up the connection.
6181 *
6182 * Returns an error message, or NULL on success.
6183 */
6184 static const char *ssh_init(void *frontend_handle, void **backend_handle,
6185 Config *cfg,
6186 char *host, int port, char **realhost, int nodelay,
6187 int keepalive)
6188 {
6189 const char *p;
6190 Ssh ssh;
6191
6192 ssh = snew(struct ssh_tag);
6193 ssh->cfg = *cfg; /* STRUCTURE COPY */
6194 ssh->version = 0; /* when not ready yet */
6195 ssh->s = NULL;
6196 ssh->cipher = NULL;
6197 ssh->v1_cipher_ctx = NULL;
6198 ssh->crcda_ctx = NULL;
6199 ssh->cscipher = NULL;
6200 ssh->cs_cipher_ctx = NULL;
6201 ssh->sccipher = NULL;
6202 ssh->sc_cipher_ctx = NULL;
6203 ssh->csmac = NULL;
6204 ssh->cs_mac_ctx = NULL;
6205 ssh->scmac = NULL;
6206 ssh->sc_mac_ctx = NULL;
6207 ssh->cscomp = NULL;
6208 ssh->cs_comp_ctx = NULL;
6209 ssh->sccomp = NULL;
6210 ssh->sc_comp_ctx = NULL;
6211 ssh->kex = NULL;
6212 ssh->kex_ctx = NULL;
6213 ssh->hostkey = NULL;
6214 ssh->exitcode = -1;
6215 ssh->state = SSH_STATE_PREPACKET;
6216 ssh->size_needed = FALSE;
6217 ssh->eof_needed = FALSE;
6218 ssh->ldisc = NULL;
6219 ssh->logctx = NULL;
6220 {
6221 static const struct Packet empty = { 0, 0, NULL, NULL, 0 };
6222 ssh->pktin = ssh->pktout = empty;
6223 }
6224 ssh->deferred_send_data = NULL;
6225 ssh->deferred_len = 0;
6226 ssh->deferred_size = 0;
6227 ssh->fallback_cmd = 0;
6228 ssh->pkt_ctx = 0;
6229 ssh->x11auth = NULL;
6230 ssh->v1_compressing = FALSE;
6231 ssh->v2_outgoing_sequence = 0;
6232 ssh->ssh1_rdpkt_crstate = 0;
6233 ssh->ssh2_rdpkt_crstate = 0;
6234 ssh->do_ssh_init_crstate = 0;
6235 ssh->ssh_gotdata_crstate = 0;
6236 ssh->ssh1_protocol_crstate = 0;
6237 ssh->do_ssh1_login_crstate = 0;
6238 ssh->do_ssh2_transport_crstate = 0;
6239 ssh->do_ssh2_authconn_crstate = 0;
6240 ssh->do_ssh_init_state = NULL;
6241 ssh->do_ssh1_login_state = NULL;
6242 ssh->do_ssh2_transport_state = NULL;
6243 ssh->do_ssh2_authconn_state = NULL;
6244 ssh->mainchan = NULL;
6245 ssh->throttled_all = 0;
6246 ssh->v1_stdout_throttling = 0;
6247
6248 *backend_handle = ssh;
6249
6250 #ifdef MSCRYPTOAPI
6251 if (crypto_startup() == 0)
6252 return "Microsoft high encryption pack not installed!";
6253 #endif
6254
6255 ssh->frontend = frontend_handle;
6256 ssh->term_width = ssh->cfg.width;
6257 ssh->term_height = ssh->cfg.height;
6258
6259 ssh->channels = NULL;
6260 ssh->rportfwds = NULL;
6261
6262 ssh->send_ok = 0;
6263 ssh->editing = 0;
6264 ssh->echoing = 0;
6265 ssh->v1_throttle_count = 0;
6266 ssh->overall_bufsize = 0;
6267 ssh->fallback_cmd = 0;
6268
6269 ssh->protocol = NULL;
6270
6271 p = connect_to_host(ssh, host, port, realhost, nodelay, keepalive);
6272 if (p != NULL)
6273 return p;
6274
6275 return NULL;
6276 }
6277
6278 static void ssh_free(void *handle)
6279 {
6280 Ssh ssh = (Ssh) handle;
6281 struct ssh_channel *c;
6282 struct ssh_rportfwd *pf;
6283
6284 if (ssh->v1_cipher_ctx)
6285 ssh->cipher->free_context(ssh->v1_cipher_ctx);
6286 if (ssh->cs_cipher_ctx)
6287 ssh->cscipher->free_context(ssh->cs_cipher_ctx);
6288 if (ssh->sc_cipher_ctx)
6289 ssh->sccipher->free_context(ssh->sc_cipher_ctx);
6290 if (ssh->cs_mac_ctx)
6291 ssh->csmac->free_context(ssh->cs_mac_ctx);
6292 if (ssh->sc_mac_ctx)
6293 ssh->scmac->free_context(ssh->sc_mac_ctx);
6294 if (ssh->cs_comp_ctx) {
6295 if (ssh->cscomp)
6296 ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
6297 else
6298 zlib_compress_cleanup(ssh->cs_comp_ctx);
6299 }
6300 if (ssh->sc_comp_ctx) {
6301 if (ssh->sccomp)
6302 ssh->sccomp->decompress_cleanup(ssh->sc_comp_ctx);
6303 else
6304 zlib_decompress_cleanup(ssh->sc_comp_ctx);
6305 }
6306 if (ssh->kex_ctx)
6307 dh_cleanup(ssh->kex_ctx);
6308 sfree(ssh->savedhost);
6309
6310 if (ssh->channels) {
6311 while ((c = delpos234(ssh->channels, 0)) != NULL) {
6312 switch (c->type) {
6313 case CHAN_X11:
6314 if (c->u.x11.s != NULL)
6315 x11_close(c->u.x11.s);
6316 break;
6317 case CHAN_SOCKDATA:
6318 if (c->u.pfd.s != NULL)
6319 pfd_close(c->u.pfd.s);
6320 break;
6321 }
6322 sfree(c);
6323 }
6324 freetree234(ssh->channels);
6325 }
6326
6327 if (ssh->rportfwds) {
6328 while ((pf = delpos234(ssh->rportfwds, 0)) != NULL)
6329 sfree(pf);
6330 freetree234(ssh->rportfwds);
6331 }
6332 sfree(ssh->deferred_send_data);
6333 if (ssh->x11auth)
6334 x11_free_auth(ssh->x11auth);
6335 sfree(ssh->do_ssh_init_state);
6336 sfree(ssh->do_ssh1_login_state);
6337 sfree(ssh->do_ssh2_transport_state);
6338 sfree(ssh->do_ssh2_authconn_state);
6339 if (ssh->pktout.data) {
6340 sfree(ssh->pktout.data);
6341 ssh->pktout.data = NULL;
6342 }
6343 if (ssh->pktin.data) {
6344 sfree(ssh->pktin.data);
6345 ssh->pktin.data = NULL;
6346 }
6347 if (ssh->crcda_ctx) {
6348 crcda_free_context(ssh->crcda_ctx);
6349 ssh->crcda_ctx = NULL;
6350 }
6351 if (ssh->logctx) {
6352 log_free(ssh->logctx);
6353 ssh->logctx = NULL;
6354 }
6355 if (ssh->s)
6356 ssh_do_close(ssh);
6357 sfree(ssh);
6358 }
6359
6360 /*
6361 * Reconfigure the SSH backend.
6362 *
6363 * Currently, this function does nothing very useful. In future,
6364 * however, we could do some handy things with it. For example, we
6365 * could make the port forwarding configurer active in the Change
6366 * Settings box, and this routine could close down existing
6367 * forwardings and open up new ones in response to changes.
6368 */
6369 static void ssh_reconfig(void *handle, Config *cfg)
6370 {
6371 Ssh ssh = (Ssh) handle;
6372 ssh->cfg = *cfg; /* STRUCTURE COPY */
6373 }
6374
6375 /*
6376 * Called to send data down the Telnet connection.
6377 */
6378 static int ssh_send(void *handle, char *buf, int len)
6379 {
6380 Ssh ssh = (Ssh) handle;
6381
6382 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
6383 return 0;
6384
6385 ssh->protocol(ssh, (unsigned char *)buf, len, 0);
6386
6387 return ssh_sendbuffer(ssh);
6388 }
6389
6390 /*
6391 * Called to query the current amount of buffered stdin data.
6392 */
6393 static int ssh_sendbuffer(void *handle)
6394 {
6395 Ssh ssh = (Ssh) handle;
6396 int override_value;
6397
6398 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
6399 return 0;
6400
6401 /*
6402 * If the SSH socket itself has backed up, add the total backup
6403 * size on that to any individual buffer on the stdin channel.
6404 */
6405 override_value = 0;
6406 if (ssh->throttled_all)
6407 override_value = ssh->overall_bufsize;
6408
6409 if (ssh->version == 1) {
6410 return override_value;
6411 } else if (ssh->version == 2) {
6412 if (!ssh->mainchan || ssh->mainchan->closes > 0)
6413 return override_value;
6414 else
6415 return (override_value +
6416 bufchain_size(&ssh->mainchan->v.v2.outbuffer));
6417 }
6418
6419 return 0;
6420 }
6421
6422 /*
6423 * Called to set the size of the window from SSH's POV.
6424 */
6425 static void ssh_size(void *handle, int width, int height)
6426 {
6427 Ssh ssh = (Ssh) handle;
6428
6429 ssh->term_width = width;
6430 ssh->term_height = height;
6431
6432 switch (ssh->state) {
6433 case SSH_STATE_BEFORE_SIZE:
6434 case SSH_STATE_PREPACKET:
6435 case SSH_STATE_CLOSED:
6436 break; /* do nothing */
6437 case SSH_STATE_INTERMED:
6438 ssh->size_needed = TRUE; /* buffer for later */
6439 break;
6440 case SSH_STATE_SESSION:
6441 if (!ssh->cfg.nopty) {
6442 if (ssh->version == 1) {
6443 send_packet(ssh, SSH1_CMSG_WINDOW_SIZE,
6444 PKT_INT, ssh->term_height,
6445 PKT_INT, ssh->term_width,
6446 PKT_INT, 0, PKT_INT, 0, PKT_END);
6447 } else {
6448 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
6449 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
6450 ssh2_pkt_addstring(ssh, "window-change");
6451 ssh2_pkt_addbool(ssh, 0);
6452 ssh2_pkt_adduint32(ssh, ssh->term_width);
6453 ssh2_pkt_adduint32(ssh, ssh->term_height);
6454 ssh2_pkt_adduint32(ssh, 0);
6455 ssh2_pkt_adduint32(ssh, 0);
6456 ssh2_pkt_send(ssh);
6457 }
6458 }
6459 break;
6460 }
6461 }
6462
6463 /*
6464 * Return a list of the special codes that make sense in this
6465 * protocol.
6466 */
6467 static const struct telnet_special *ssh_get_specials(void *handle)
6468 {
6469 Ssh ssh = (Ssh) handle;
6470
6471 if (ssh->version == 1) {
6472 static const struct telnet_special ssh1_specials[] = {
6473 {"IGNORE message", TS_NOP},
6474 {NULL, 0}
6475 };
6476 return ssh1_specials;
6477 } else if (ssh->version == 2) {
6478 static const struct telnet_special ssh2_specials[] = {
6479 {"Break", TS_BRK},
6480 {"IGNORE message", TS_NOP},
6481 {NULL, 0}
6482 };
6483 return ssh2_specials;
6484 } else
6485 return NULL;
6486 }
6487
6488 /*
6489 * Send Telnet special codes. TS_EOF is useful for `plink', so you
6490 * can send an EOF and collect resulting output (e.g. `plink
6491 * hostname sort').
6492 */
6493 static void ssh_special(void *handle, Telnet_Special code)
6494 {
6495 Ssh ssh = (Ssh) handle;
6496
6497 if (code == TS_EOF) {
6498 if (ssh->state != SSH_STATE_SESSION) {
6499 /*
6500 * Buffer the EOF in case we are pre-SESSION, so we can
6501 * send it as soon as we reach SESSION.
6502 */
6503 if (code == TS_EOF)
6504 ssh->eof_needed = TRUE;
6505 return;
6506 }
6507 if (ssh->version == 1) {
6508 send_packet(ssh, SSH1_CMSG_EOF, PKT_END);
6509 } else {
6510 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_EOF);
6511 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
6512 ssh2_pkt_send(ssh);
6513 }
6514 logevent("Sent EOF message");
6515 } else if (code == TS_PING || code == TS_NOP) {
6516 if (ssh->state == SSH_STATE_CLOSED
6517 || ssh->state == SSH_STATE_PREPACKET) return;
6518 if (ssh->version == 1) {
6519 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE))
6520 send_packet(ssh, SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
6521 } else {
6522 ssh2_pkt_init(ssh, SSH2_MSG_IGNORE);
6523 ssh2_pkt_addstring_start(ssh);
6524 ssh2_pkt_send(ssh);
6525 }
6526 } else if (code == TS_BRK) {
6527 if (ssh->state == SSH_STATE_CLOSED
6528 || ssh->state == SSH_STATE_PREPACKET) return;
6529 if (ssh->version == 1) {
6530 logevent("Unable to send BREAK signal in SSH1");
6531 } else {
6532 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
6533 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
6534 ssh2_pkt_addstring(ssh, "break");
6535 ssh2_pkt_addbool(ssh, 0);
6536 ssh2_pkt_adduint32(ssh, 0); /* default break length */
6537 ssh2_pkt_send(ssh);
6538 }
6539 } else {
6540 /* do nothing */
6541 }
6542 }
6543
6544 void *new_sock_channel(void *handle, Socket s)
6545 {
6546 Ssh ssh = (Ssh) handle;
6547 struct ssh_channel *c;
6548 c = snew(struct ssh_channel);
6549 c->ssh = ssh;
6550
6551 if (c) {
6552 c->remoteid = -1; /* to be set when open confirmed */
6553 c->localid = alloc_channel_id(ssh);
6554 c->closes = 0;
6555 c->type = CHAN_SOCKDATA_DORMANT;/* identify channel type */
6556 c->u.pfd.s = s;
6557 bufchain_init(&c->v.v2.outbuffer);
6558 add234(ssh->channels, c);
6559 }
6560 return c;
6561 }
6562
6563 /*
6564 * This is called when stdout/stderr (the entity to which
6565 * from_backend sends data) manages to clear some backlog.
6566 */
6567 static void ssh_unthrottle(void *handle, int bufsize)
6568 {
6569 Ssh ssh = (Ssh) handle;
6570 if (ssh->version == 1) {
6571 if (ssh->v1_stdout_throttling && bufsize < SSH1_BUFFER_LIMIT) {
6572 ssh->v1_stdout_throttling = 0;
6573 ssh1_throttle(ssh, -1);
6574 }
6575 } else {
6576 if (ssh->mainchan && ssh->mainchan->closes == 0)
6577 ssh2_set_window(ssh->mainchan, OUR_V2_WINSIZE - bufsize);
6578 }
6579 }
6580
6581 void ssh_send_port_open(void *channel, char *hostname, int port, char *org)
6582 {
6583 struct ssh_channel *c = (struct ssh_channel *)channel;
6584 Ssh ssh = c->ssh;
6585
6586 logeventf(ssh, "Opening forwarded connection to %s:%d", hostname, port);
6587
6588 if (ssh->version == 1) {
6589 send_packet(ssh, SSH1_MSG_PORT_OPEN,
6590 PKT_INT, c->localid,
6591 PKT_STR, hostname,
6592 PKT_INT, port,
6593 //PKT_STR, <org:orgport>,
6594 PKT_END);
6595 } else {
6596 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN);
6597 ssh2_pkt_addstring(ssh, "direct-tcpip");
6598 ssh2_pkt_adduint32(ssh, c->localid);
6599 c->v.v2.locwindow = OUR_V2_WINSIZE;
6600 ssh2_pkt_adduint32(ssh, c->v.v2.locwindow);/* our window size */
6601 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
6602 ssh2_pkt_addstring(ssh, hostname);
6603 ssh2_pkt_adduint32(ssh, port);
6604 /*
6605 * We make up values for the originator data; partly it's
6606 * too much hassle to keep track, and partly I'm not
6607 * convinced the server should be told details like that
6608 * about my local network configuration.
6609 */
6610 ssh2_pkt_addstring(ssh, "client-side-connection");
6611 ssh2_pkt_adduint32(ssh, 0);
6612 ssh2_pkt_send(ssh);
6613 }
6614 }
6615
6616
6617 static Socket ssh_socket(void *handle)
6618 {
6619 Ssh ssh = (Ssh) handle;
6620 return ssh->s;
6621 }
6622
6623 static int ssh_sendok(void *handle)
6624 {
6625 Ssh ssh = (Ssh) handle;
6626 return ssh->send_ok;
6627 }
6628
6629 static int ssh_ldisc(void *handle, int option)
6630 {
6631 Ssh ssh = (Ssh) handle;
6632 if (option == LD_ECHO)
6633 return ssh->echoing;
6634 if (option == LD_EDIT)
6635 return ssh->editing;
6636 return FALSE;
6637 }
6638
6639 static void ssh_provide_ldisc(void *handle, void *ldisc)
6640 {
6641 Ssh ssh = (Ssh) handle;
6642 ssh->ldisc = ldisc;
6643 }
6644
6645 static void ssh_provide_logctx(void *handle, void *logctx)
6646 {
6647 Ssh ssh = (Ssh) handle;
6648 ssh->logctx = logctx;
6649 }
6650
6651 static int ssh_return_exitcode(void *handle)
6652 {
6653 Ssh ssh = (Ssh) handle;
6654 if (ssh->s != NULL)
6655 return -1;
6656 else
6657 return (ssh->exitcode >= 0 ? ssh->exitcode : 0);
6658 }
6659
6660 /*
6661 * Gross hack: pscp will try to start SFTP but fall back to scp1 if
6662 * that fails. This variable is the means by which scp.c can reach
6663 * into the SSH code and find out which one it got.
6664 */
6665 extern int ssh_fallback_cmd(void *handle)
6666 {
6667 Ssh ssh = (Ssh) handle;
6668 return ssh->fallback_cmd;
6669 }
6670
6671 Backend ssh_backend = {
6672 ssh_init,
6673 ssh_free,
6674 ssh_reconfig,
6675 ssh_send,
6676 ssh_sendbuffer,
6677 ssh_size,
6678 ssh_special,
6679 ssh_get_specials,
6680 ssh_socket,
6681 ssh_return_exitcode,
6682 ssh_sendok,
6683 ssh_ldisc,
6684 ssh_provide_ldisc,
6685 ssh_provide_logctx,
6686 ssh_unthrottle,
6687 22
6688 };
Local modifications for Simon Tatham's `PuTTY' SSH client and terminal emulator