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1b2e7e12af0d36b4f4c238b6efdb7c0f331ab212
[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
167 #define translate(x) if (type == x) return #x
168 #define translatec(x,ctx) if (type == x && (pkt_ctx & ctx)) return #x
169 static char *ssh1_pkt_type(int type)
170 {
171 translate(SSH1_MSG_DISCONNECT);
172 translate(SSH1_SMSG_PUBLIC_KEY);
173 translate(SSH1_CMSG_SESSION_KEY);
174 translate(SSH1_CMSG_USER);
175 translate(SSH1_CMSG_AUTH_RSA);
176 translate(SSH1_SMSG_AUTH_RSA_CHALLENGE);
177 translate(SSH1_CMSG_AUTH_RSA_RESPONSE);
178 translate(SSH1_CMSG_AUTH_PASSWORD);
179 translate(SSH1_CMSG_REQUEST_PTY);
180 translate(SSH1_CMSG_WINDOW_SIZE);
181 translate(SSH1_CMSG_EXEC_SHELL);
182 translate(SSH1_CMSG_EXEC_CMD);
183 translate(SSH1_SMSG_SUCCESS);
184 translate(SSH1_SMSG_FAILURE);
185 translate(SSH1_CMSG_STDIN_DATA);
186 translate(SSH1_SMSG_STDOUT_DATA);
187 translate(SSH1_SMSG_STDERR_DATA);
188 translate(SSH1_CMSG_EOF);
189 translate(SSH1_SMSG_EXIT_STATUS);
190 translate(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION);
191 translate(SSH1_MSG_CHANNEL_OPEN_FAILURE);
192 translate(SSH1_MSG_CHANNEL_DATA);
193 translate(SSH1_MSG_CHANNEL_CLOSE);
194 translate(SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION);
195 translate(SSH1_SMSG_X11_OPEN);
196 translate(SSH1_CMSG_PORT_FORWARD_REQUEST);
197 translate(SSH1_MSG_PORT_OPEN);
198 translate(SSH1_CMSG_AGENT_REQUEST_FORWARDING);
199 translate(SSH1_SMSG_AGENT_OPEN);
200 translate(SSH1_MSG_IGNORE);
201 translate(SSH1_CMSG_EXIT_CONFIRMATION);
202 translate(SSH1_CMSG_X11_REQUEST_FORWARDING);
203 translate(SSH1_CMSG_AUTH_RHOSTS_RSA);
204 translate(SSH1_MSG_DEBUG);
205 translate(SSH1_CMSG_REQUEST_COMPRESSION);
206 translate(SSH1_CMSG_AUTH_TIS);
207 translate(SSH1_SMSG_AUTH_TIS_CHALLENGE);
208 translate(SSH1_CMSG_AUTH_TIS_RESPONSE);
209 translate(SSH1_CMSG_AUTH_CCARD);
210 translate(SSH1_SMSG_AUTH_CCARD_CHALLENGE);
211 translate(SSH1_CMSG_AUTH_CCARD_RESPONSE);
212 return "unknown";
213 }
214 static char *ssh2_pkt_type(int pkt_ctx, int type)
215 {
216 translate(SSH2_MSG_DISCONNECT);
217 translate(SSH2_MSG_IGNORE);
218 translate(SSH2_MSG_UNIMPLEMENTED);
219 translate(SSH2_MSG_DEBUG);
220 translate(SSH2_MSG_SERVICE_REQUEST);
221 translate(SSH2_MSG_SERVICE_ACCEPT);
222 translate(SSH2_MSG_KEXINIT);
223 translate(SSH2_MSG_NEWKEYS);
224 translatec(SSH2_MSG_KEXDH_INIT, SSH2_PKTCTX_DHGROUP1);
225 translatec(SSH2_MSG_KEXDH_REPLY, SSH2_PKTCTX_DHGROUP1);
226 translatec(SSH2_MSG_KEX_DH_GEX_REQUEST, SSH2_PKTCTX_DHGEX);
227 translatec(SSH2_MSG_KEX_DH_GEX_GROUP, SSH2_PKTCTX_DHGEX);
228 translatec(SSH2_MSG_KEX_DH_GEX_INIT, SSH2_PKTCTX_DHGEX);
229 translatec(SSH2_MSG_KEX_DH_GEX_REPLY, SSH2_PKTCTX_DHGEX);
230 translate(SSH2_MSG_USERAUTH_REQUEST);
231 translate(SSH2_MSG_USERAUTH_FAILURE);
232 translate(SSH2_MSG_USERAUTH_SUCCESS);
233 translate(SSH2_MSG_USERAUTH_BANNER);
234 translatec(SSH2_MSG_USERAUTH_PK_OK, SSH2_PKTCTX_PUBLICKEY);
235 translatec(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, SSH2_PKTCTX_PASSWORD);
236 translatec(SSH2_MSG_USERAUTH_INFO_REQUEST, SSH2_PKTCTX_KBDINTER);
237 translatec(SSH2_MSG_USERAUTH_INFO_RESPONSE, SSH2_PKTCTX_KBDINTER);
238 translate(SSH2_MSG_GLOBAL_REQUEST);
239 translate(SSH2_MSG_REQUEST_SUCCESS);
240 translate(SSH2_MSG_REQUEST_FAILURE);
241 translate(SSH2_MSG_CHANNEL_OPEN);
242 translate(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
243 translate(SSH2_MSG_CHANNEL_OPEN_FAILURE);
244 translate(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
245 translate(SSH2_MSG_CHANNEL_DATA);
246 translate(SSH2_MSG_CHANNEL_EXTENDED_DATA);
247 translate(SSH2_MSG_CHANNEL_EOF);
248 translate(SSH2_MSG_CHANNEL_CLOSE);
249 translate(SSH2_MSG_CHANNEL_REQUEST);
250 translate(SSH2_MSG_CHANNEL_SUCCESS);
251 translate(SSH2_MSG_CHANNEL_FAILURE);
252 return "unknown";
253 }
254 #undef translate
255 #undef translatec
256
257 #define GET_32BIT(cp) \
258 (((unsigned long)(unsigned char)(cp)[0] << 24) | \
259 ((unsigned long)(unsigned char)(cp)[1] << 16) | \
260 ((unsigned long)(unsigned char)(cp)[2] << 8) | \
261 ((unsigned long)(unsigned char)(cp)[3]))
262
263 #define PUT_32BIT(cp, value) { \
264 (cp)[0] = (unsigned char)((value) >> 24); \
265 (cp)[1] = (unsigned char)((value) >> 16); \
266 (cp)[2] = (unsigned char)((value) >> 8); \
267 (cp)[3] = (unsigned char)(value); }
268
269 enum { PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR, PKT_BIGNUM };
270
271 /* Coroutine mechanics for the sillier bits of the code */
272 #define crBegin(v) { int *crLine = &v; switch(v) { case 0:;
273 #define crState(t) \
274 struct t *s; \
275 if (!ssh->t) ssh->t = smalloc(sizeof(struct t)); \
276 s = ssh->t;
277 #define crFinish(z) } *crLine = 0; return (z); }
278 #define crFinishV } *crLine = 0; return; }
279 #define crReturn(z) \
280 do {\
281 *crLine =__LINE__; return (z); case __LINE__:;\
282 } while (0)
283 #define crReturnV \
284 do {\
285 *crLine=__LINE__; return; case __LINE__:;\
286 } while (0)
287 #define crStop(z) do{ *crLine = 0; return (z); }while(0)
288 #define crStopV do{ *crLine = 0; return; }while(0)
289 #define crWaitUntil(c) do { crReturn(0); } while (!(c))
290 #define crWaitUntilV(c) do { crReturnV; } while (!(c))
291
292 typedef struct ssh_tag *Ssh;
293
294 static void ssh2_pkt_init(Ssh, int pkt_type);
295 static void ssh2_pkt_addbool(Ssh, unsigned char value);
296 static void ssh2_pkt_adduint32(Ssh, unsigned long value);
297 static void ssh2_pkt_addstring_start(Ssh);
298 static void ssh2_pkt_addstring_str(Ssh, char *data);
299 static void ssh2_pkt_addstring_data(Ssh, char *data, int len);
300 static void ssh2_pkt_addstring(Ssh, char *data);
301 static unsigned char *ssh2_mpint_fmt(Bignum b, int *len);
302 static void ssh2_pkt_addmp(Ssh, Bignum b);
303 static int ssh2_pkt_construct(Ssh);
304 static void ssh2_pkt_send(Ssh);
305
306 /*
307 * Buffer management constants. There are several of these for
308 * various different purposes:
309 *
310 * - SSH1_BUFFER_LIMIT is the amount of backlog that must build up
311 * on a local data stream before we throttle the whole SSH
312 * connection (in SSH1 only). Throttling the whole connection is
313 * pretty drastic so we set this high in the hope it won't
314 * happen very often.
315 *
316 * - SSH_MAX_BACKLOG is the amount of backlog that must build up
317 * on the SSH connection itself before we defensively throttle
318 * _all_ local data streams. This is pretty drastic too (though
319 * thankfully unlikely in SSH2 since the window mechanism should
320 * ensure that the server never has any need to throttle its end
321 * of the connection), so we set this high as well.
322 *
323 * - OUR_V2_WINSIZE is the maximum window size we present on SSH2
324 * channels.
325 */
326
327 #define SSH1_BUFFER_LIMIT 32768
328 #define SSH_MAX_BACKLOG 32768
329 #define OUR_V2_WINSIZE 16384
330
331 const static struct ssh_kex *kex_algs[] = {
332 &ssh_diffiehellman_gex,
333 &ssh_diffiehellman
334 };
335
336 const static struct ssh_signkey *hostkey_algs[] = { &ssh_rsa, &ssh_dss };
337
338 static void *nullmac_make_context(void)
339 {
340 return NULL;
341 }
342 static void nullmac_free_context(void *handle)
343 {
344 }
345 static void nullmac_key(void *handle, unsigned char *key)
346 {
347 }
348 static void nullmac_generate(void *handle, unsigned char *blk, int len,
349 unsigned long seq)
350 {
351 }
352 static int nullmac_verify(void *handle, unsigned char *blk, int len,
353 unsigned long seq)
354 {
355 return 1;
356 }
357 const static struct ssh_mac ssh_mac_none = {
358 nullmac_make_context, nullmac_free_context, nullmac_key,
359 nullmac_generate, nullmac_verify, "none", 0
360 };
361 const static struct ssh_mac *macs[] = {
362 &ssh_sha1, &ssh_md5, &ssh_mac_none
363 };
364 const static struct ssh_mac *buggymacs[] = {
365 &ssh_sha1_buggy, &ssh_md5, &ssh_mac_none
366 };
367
368 static void *ssh_comp_none_init(void)
369 {
370 return NULL;
371 }
372 static void ssh_comp_none_cleanup(void *handle)
373 {
374 }
375 static int ssh_comp_none_block(void *handle, unsigned char *block, int len,
376 unsigned char **outblock, int *outlen)
377 {
378 return 0;
379 }
380 static int ssh_comp_none_disable(void *handle)
381 {
382 return 0;
383 }
384 const static struct ssh_compress ssh_comp_none = {
385 "none",
386 ssh_comp_none_init, ssh_comp_none_cleanup, ssh_comp_none_block,
387 ssh_comp_none_init, ssh_comp_none_cleanup, ssh_comp_none_block,
388 ssh_comp_none_disable, NULL
389 };
390 extern const struct ssh_compress ssh_zlib;
391 const static struct ssh_compress *compressions[] = {
392 &ssh_zlib, &ssh_comp_none
393 };
394
395 enum { /* channel types */
396 CHAN_MAINSESSION,
397 CHAN_X11,
398 CHAN_AGENT,
399 CHAN_SOCKDATA,
400 CHAN_SOCKDATA_DORMANT /* one the remote hasn't confirmed */
401 };
402
403 /*
404 * 2-3-4 tree storing channels.
405 */
406 struct ssh_channel {
407 Ssh ssh; /* pointer back to main context */
408 unsigned remoteid, localid;
409 int type;
410 /*
411 * In SSH1, this value contains four bits:
412 *
413 * 1 We have sent SSH1_MSG_CHANNEL_CLOSE.
414 * 2 We have sent SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION.
415 * 4 We have received SSH1_MSG_CHANNEL_CLOSE.
416 * 8 We have received SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION.
417 *
418 * A channel is completely finished with when all four bits are set.
419 */
420 int closes;
421 union {
422 struct ssh1_data_channel {
423 int throttling;
424 } v1;
425 struct ssh2_data_channel {
426 bufchain outbuffer;
427 unsigned remwindow, remmaxpkt;
428 unsigned locwindow;
429 } v2;
430 } v;
431 union {
432 struct ssh_agent_channel {
433 unsigned char *message;
434 unsigned char msglen[4];
435 int lensofar, totallen;
436 } a;
437 struct ssh_x11_channel {
438 Socket s;
439 } x11;
440 struct ssh_pfd_channel {
441 Socket s;
442 } pfd;
443 } u;
444 };
445
446 /*
447 * 2-3-4 tree storing remote->local port forwardings. SSH 1 and SSH
448 * 2 use this structure in different ways, reflecting SSH 2's
449 * altogether saner approach to port forwarding.
450 *
451 * In SSH 1, you arrange a remote forwarding by sending the server
452 * the remote port number, and the local destination host:port.
453 * When a connection comes in, the server sends you back that
454 * host:port pair, and you connect to it. This is a ready-made
455 * security hole if you're not on the ball: a malicious server
456 * could send you back _any_ host:port pair, so if you trustingly
457 * connect to the address it gives you then you've just opened the
458 * entire inside of your corporate network just by connecting
459 * through it to a dodgy SSH server. Hence, we must store a list of
460 * host:port pairs we _are_ trying to forward to, and reject a
461 * connection request from the server if it's not in the list.
462 *
463 * In SSH 2, each side of the connection minds its own business and
464 * doesn't send unnecessary information to the other. You arrange a
465 * remote forwarding by sending the server just the remote port
466 * number. When a connection comes in, the server tells you which
467 * of its ports was connected to; and _you_ have to remember what
468 * local host:port pair went with that port number.
469 *
470 * Hence: in SSH 1 this structure stores host:port pairs we intend
471 * to allow connections to, and is indexed by those host:port
472 * pairs. In SSH 2 it stores a mapping from source port to
473 * destination host:port pair, and is indexed by source port.
474 */
475 struct ssh_rportfwd {
476 unsigned sport, dport;
477 char dhost[256];
478 };
479
480 struct Packet {
481 long length;
482 int type;
483 unsigned char *data;
484 unsigned char *body;
485 long savedpos;
486 long maxlen;
487 };
488
489 static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt);
490 static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt);
491 static void ssh_size(void *handle, int width, int height);
492 static void ssh_special(void *handle, Telnet_Special);
493 static int ssh2_try_send(struct ssh_channel *c);
494 static void ssh2_add_channel_data(struct ssh_channel *c, char *buf, int len);
495 static void ssh_throttle_all(Ssh ssh, int enable, int bufsize);
496 static void ssh2_set_window(struct ssh_channel *c, unsigned newwin);
497 static int ssh_sendbuffer(void *handle);
498
499 struct rdpkt1_state_tag {
500 long len, pad, biglen, to_read;
501 unsigned long realcrc, gotcrc;
502 unsigned char *p;
503 int i;
504 int chunk;
505 };
506
507 struct rdpkt2_state_tag {
508 long len, pad, payload, packetlen, maclen;
509 int i;
510 int cipherblk;
511 unsigned long incoming_sequence;
512 };
513
514 struct ssh_tag {
515 const struct plug_function_table *fn;
516 /* the above field _must_ be first in the structure */
517
518 SHA_State exhash, exhashbase;
519
520 Socket s;
521
522 void *ldisc;
523 void *logctx;
524
525 unsigned char session_key[32];
526 int v1_compressing;
527 int v1_remote_protoflags;
528 int v1_local_protoflags;
529 int agentfwd_enabled;
530 int X11_fwd_enabled;
531 int remote_bugs;
532 const struct ssh_cipher *cipher;
533 void *v1_cipher_ctx;
534 void *crcda_ctx;
535 const struct ssh2_cipher *cscipher, *sccipher;
536 void *cs_cipher_ctx, *sc_cipher_ctx;
537 const struct ssh_mac *csmac, *scmac;
538 void *cs_mac_ctx, *sc_mac_ctx;
539 const struct ssh_compress *cscomp, *sccomp;
540 void *cs_comp_ctx, *sc_comp_ctx;
541 const struct ssh_kex *kex;
542 const struct ssh_signkey *hostkey;
543 unsigned char v2_session_id[20];
544 void *kex_ctx;
545
546 char *savedhost;
547 int savedport;
548 int send_ok;
549 int echoing, editing;
550
551 void *frontend;
552
553 int term_width, term_height;
554
555 tree234 *channels; /* indexed by local id */
556 struct ssh_channel *mainchan; /* primary session channel */
557 int exitcode;
558
559 tree234 *rportfwds;
560
561 enum {
562 SSH_STATE_PREPACKET,
563 SSH_STATE_BEFORE_SIZE,
564 SSH_STATE_INTERMED,
565 SSH_STATE_SESSION,
566 SSH_STATE_CLOSED
567 } state;
568
569 int size_needed, eof_needed;
570
571 struct Packet pktin;
572 struct Packet pktout;
573 unsigned char *deferred_send_data;
574 int deferred_len, deferred_size;
575
576 /*
577 * Gross hack: pscp will try to start SFTP but fall back to
578 * scp1 if that fails. This variable is the means by which
579 * scp.c can reach into the SSH code and find out which one it
580 * got.
581 */
582 int fallback_cmd;
583
584 /*
585 * Used for username and password input.
586 */
587 char *userpass_input_buffer;
588 int userpass_input_buflen;
589 int userpass_input_bufpos;
590 int userpass_input_echo;
591
592 char *portfwd_strptr;
593 int pkt_ctx;
594
595 void *x11auth;
596
597 int version;
598 int v1_throttle_count;
599 int overall_bufsize;
600 int throttled_all;
601 int v1_stdout_throttling;
602 int v2_outgoing_sequence;
603
604 int ssh1_rdpkt_crstate;
605 int ssh2_rdpkt_crstate;
606 int do_ssh_init_crstate;
607 int ssh_gotdata_crstate;
608 int ssh1_protocol_crstate;
609 int do_ssh1_login_crstate;
610 int do_ssh2_transport_crstate;
611 int do_ssh2_authconn_crstate;
612
613 void *do_ssh_init_state;
614 void *do_ssh1_login_state;
615 void *do_ssh2_transport_state;
616 void *do_ssh2_authconn_state;
617
618 struct rdpkt1_state_tag rdpkt1_state;
619 struct rdpkt2_state_tag rdpkt2_state;
620
621 void (*protocol) (Ssh ssh, unsigned char *in, int inlen, int ispkt);
622 int (*s_rdpkt) (Ssh ssh, unsigned char **data, int *datalen);
623
624 /*
625 * We maintain a full _copy_ of a Config structure here, not
626 * merely a pointer to it. That way, when we're passed a new
627 * one for reconfiguration, we can check the differences and
628 * potentially reconfigure port forwardings etc in mid-session.
629 */
630 Config cfg;
631 };
632
633 #define logevent(s) logevent(ssh->frontend, s)
634
635 /* logevent, only printf-formatted. */
636 static void logeventf(Ssh ssh, char *fmt, ...)
637 {
638 va_list ap;
639 char *buf;
640
641 va_start(ap, fmt);
642 buf = dupvprintf(fmt, ap);
643 va_end(ap);
644 logevent(buf);
645 sfree(buf);
646 }
647
648 #define bombout(msg) ( ssh->state = SSH_STATE_CLOSED, \
649 (ssh->s ? sk_close(ssh->s), ssh->s = NULL : 0), \
650 logeventf msg, connection_fatal msg )
651
652 static int ssh_channelcmp(void *av, void *bv)
653 {
654 struct ssh_channel *a = (struct ssh_channel *) av;
655 struct ssh_channel *b = (struct ssh_channel *) bv;
656 if (a->localid < b->localid)
657 return -1;
658 if (a->localid > b->localid)
659 return +1;
660 return 0;
661 }
662 static int ssh_channelfind(void *av, void *bv)
663 {
664 unsigned *a = (unsigned *) av;
665 struct ssh_channel *b = (struct ssh_channel *) bv;
666 if (*a < b->localid)
667 return -1;
668 if (*a > b->localid)
669 return +1;
670 return 0;
671 }
672
673 static int ssh_rportcmp_ssh1(void *av, void *bv)
674 {
675 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
676 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
677 int i;
678 if ( (i = strcmp(a->dhost, b->dhost)) != 0)
679 return i < 0 ? -1 : +1;
680 if (a->dport > b->dport)
681 return +1;
682 if (a->dport < b->dport)
683 return -1;
684 return 0;
685 }
686
687 static int ssh_rportcmp_ssh2(void *av, void *bv)
688 {
689 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
690 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
691
692 if (a->sport > b->sport)
693 return +1;
694 if (a->sport < b->sport)
695 return -1;
696 return 0;
697 }
698
699 static int alloc_channel_id(Ssh ssh)
700 {
701 const unsigned CHANNEL_NUMBER_OFFSET = 256;
702 unsigned low, high, mid;
703 int tsize;
704 struct ssh_channel *c;
705
706 /*
707 * First-fit allocation of channel numbers: always pick the
708 * lowest unused one. To do this, binary-search using the
709 * counted B-tree to find the largest channel ID which is in a
710 * contiguous sequence from the beginning. (Precisely
711 * everything in that sequence must have ID equal to its tree
712 * index plus CHANNEL_NUMBER_OFFSET.)
713 */
714 tsize = count234(ssh->channels);
715
716 low = -1;
717 high = tsize;
718 while (high - low > 1) {
719 mid = (high + low) / 2;
720 c = index234(ssh->channels, mid);
721 if (c->localid == mid + CHANNEL_NUMBER_OFFSET)
722 low = mid; /* this one is fine */
723 else
724 high = mid; /* this one is past it */
725 }
726 /*
727 * Now low points to either -1, or the tree index of the
728 * largest ID in the initial sequence.
729 */
730 {
731 unsigned i = low + 1 + CHANNEL_NUMBER_OFFSET;
732 assert(NULL == find234(ssh->channels, &i, ssh_channelfind));
733 }
734 return low + 1 + CHANNEL_NUMBER_OFFSET;
735 }
736
737 static void c_write(Ssh ssh, char *buf, int len)
738 {
739 if ((flags & FLAG_STDERR)) {
740 int i;
741 for (i = 0; i < len; i++)
742 if (buf[i] != '\r')
743 fputc(buf[i], stderr);
744 return;
745 }
746 from_backend(ssh->frontend, 1, buf, len);
747 }
748
749 static void c_write_untrusted(Ssh ssh, char *buf, int len)
750 {
751 int i;
752 for (i = 0; i < len; i++) {
753 if (buf[i] == '\n')
754 c_write(ssh, "\r\n", 2);
755 else if ((buf[i] & 0x60) || (buf[i] == '\r'))
756 c_write(ssh, buf + i, 1);
757 }
758 }
759
760 static void c_write_str(Ssh ssh, char *buf)
761 {
762 c_write(ssh, buf, strlen(buf));
763 }
764
765 /*
766 * Collect incoming data in the incoming packet buffer.
767 * Decipher and verify the packet when it is completely read.
768 * Drop SSH1_MSG_DEBUG and SSH1_MSG_IGNORE packets.
769 * Update the *data and *datalen variables.
770 * Return the additional nr of bytes needed, or 0 when
771 * a complete packet is available.
772 */
773 static int ssh1_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
774 {
775 struct rdpkt1_state_tag *st = &ssh->rdpkt1_state;
776
777 crBegin(ssh->ssh1_rdpkt_crstate);
778
779 next_packet:
780
781 ssh->pktin.type = 0;
782 ssh->pktin.length = 0;
783
784 for (st->i = st->len = 0; st->i < 4; st->i++) {
785 while ((*datalen) == 0)
786 crReturn(4 - st->i);
787 st->len = (st->len << 8) + **data;
788 (*data)++, (*datalen)--;
789 }
790
791 st->pad = 8 - (st->len % 8);
792 st->biglen = st->len + st->pad;
793 ssh->pktin.length = st->len - 5;
794
795 if (ssh->pktin.maxlen < st->biglen) {
796 ssh->pktin.maxlen = st->biglen;
797 ssh->pktin.data = srealloc(ssh->pktin.data, st->biglen + APIEXTRA);
798 }
799
800 st->to_read = st->biglen;
801 st->p = ssh->pktin.data;
802 while (st->to_read > 0) {
803 st->chunk = st->to_read;
804 while ((*datalen) == 0)
805 crReturn(st->to_read);
806 if (st->chunk > (*datalen))
807 st->chunk = (*datalen);
808 memcpy(st->p, *data, st->chunk);
809 *data += st->chunk;
810 *datalen -= st->chunk;
811 st->p += st->chunk;
812 st->to_read -= st->chunk;
813 }
814
815 if (ssh->cipher && detect_attack(ssh->crcda_ctx, ssh->pktin.data,
816 st->biglen, NULL)) {
817 bombout((ssh,"Network attack (CRC compensation) detected!"));
818 crReturn(0);
819 }
820
821 if (ssh->cipher)
822 ssh->cipher->decrypt(ssh->v1_cipher_ctx, ssh->pktin.data, st->biglen);
823
824 st->realcrc = crc32(ssh->pktin.data, st->biglen - 4);
825 st->gotcrc = GET_32BIT(ssh->pktin.data + st->biglen - 4);
826 if (st->gotcrc != st->realcrc) {
827 bombout((ssh,"Incorrect CRC received on packet"));
828 crReturn(0);
829 }
830
831 ssh->pktin.body = ssh->pktin.data + st->pad + 1;
832
833 if (ssh->v1_compressing) {
834 unsigned char *decompblk;
835 int decomplen;
836 zlib_decompress_block(ssh->sc_comp_ctx,
837 ssh->pktin.body - 1, ssh->pktin.length + 1,
838 &decompblk, &decomplen);
839
840 if (ssh->pktin.maxlen < st->pad + decomplen) {
841 ssh->pktin.maxlen = st->pad + decomplen;
842 ssh->pktin.data = srealloc(ssh->pktin.data,
843 ssh->pktin.maxlen + APIEXTRA);
844 ssh->pktin.body = ssh->pktin.data + st->pad + 1;
845 }
846
847 memcpy(ssh->pktin.body - 1, decompblk, decomplen);
848 sfree(decompblk);
849 ssh->pktin.length = decomplen - 1;
850 }
851
852 ssh->pktin.type = ssh->pktin.body[-1];
853
854 if (ssh->logctx)
855 log_packet(ssh->logctx,
856 PKT_INCOMING, ssh->pktin.type,
857 ssh1_pkt_type(ssh->pktin.type),
858 ssh->pktin.body, ssh->pktin.length);
859
860 if (ssh->pktin.type == SSH1_SMSG_STDOUT_DATA ||
861 ssh->pktin.type == SSH1_SMSG_STDERR_DATA ||
862 ssh->pktin.type == SSH1_MSG_DEBUG ||
863 ssh->pktin.type == SSH1_SMSG_AUTH_TIS_CHALLENGE ||
864 ssh->pktin.type == SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
865 long stringlen = GET_32BIT(ssh->pktin.body);
866 if (stringlen + 4 != ssh->pktin.length) {
867 bombout((ssh,"Received data packet with bogus string length"));
868 crReturn(0);
869 }
870 }
871
872 if (ssh->pktin.type == SSH1_MSG_DEBUG) {
873 /* log debug message */
874 char buf[512];
875 int stringlen = GET_32BIT(ssh->pktin.body);
876 strcpy(buf, "Remote debug message: ");
877 if (stringlen > 480)
878 stringlen = 480;
879 memcpy(buf + 8, ssh->pktin.body + 4, stringlen);
880 buf[8 + stringlen] = '\0';
881 logevent(buf);
882 goto next_packet;
883 } else if (ssh->pktin.type == SSH1_MSG_IGNORE) {
884 /* do nothing */
885 goto next_packet;
886 }
887
888 if (ssh->pktin.type == SSH1_MSG_DISCONNECT) {
889 /* log reason code in disconnect message */
890 char buf[256];
891 unsigned msglen = GET_32BIT(ssh->pktin.body);
892 unsigned nowlen;
893 strcpy(buf, "Remote sent disconnect: ");
894 nowlen = strlen(buf);
895 if (msglen > sizeof(buf) - nowlen - 1)
896 msglen = sizeof(buf) - nowlen - 1;
897 memcpy(buf + nowlen, ssh->pktin.body + 4, msglen);
898 buf[nowlen + msglen] = '\0';
899 /* logevent(buf); (this is now done within the bombout macro) */
900 bombout((ssh,"Server sent disconnect message:\n\"%s\"", buf+nowlen));
901 crReturn(0);
902 }
903
904 crFinish(0);
905 }
906
907 static int ssh2_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
908 {
909 struct rdpkt2_state_tag *st = &ssh->rdpkt2_state;
910
911 crBegin(ssh->ssh2_rdpkt_crstate);
912
913 next_packet:
914 ssh->pktin.type = 0;
915 ssh->pktin.length = 0;
916 if (ssh->sccipher)
917 st->cipherblk = ssh->sccipher->blksize;
918 else
919 st->cipherblk = 8;
920 if (st->cipherblk < 8)
921 st->cipherblk = 8;
922
923 if (ssh->pktin.maxlen < st->cipherblk) {
924 ssh->pktin.maxlen = st->cipherblk;
925 ssh->pktin.data = srealloc(ssh->pktin.data, st->cipherblk + APIEXTRA);
926 }
927
928 /*
929 * Acquire and decrypt the first block of the packet. This will
930 * contain the length and padding details.
931 */
932 for (st->i = st->len = 0; st->i < st->cipherblk; st->i++) {
933 while ((*datalen) == 0)
934 crReturn(st->cipherblk - st->i);
935 ssh->pktin.data[st->i] = *(*data)++;
936 (*datalen)--;
937 }
938
939 if (ssh->sccipher)
940 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
941 ssh->pktin.data, st->cipherblk);
942
943 /*
944 * Now get the length and padding figures.
945 */
946 st->len = GET_32BIT(ssh->pktin.data);
947 st->pad = ssh->pktin.data[4];
948
949 /*
950 * _Completely_ silly lengths should be stomped on before they
951 * do us any more damage.
952 */
953 if (st->len < 0 || st->pad < 0 || st->len + st->pad < 0) {
954 bombout((ssh,"Incoming packet was garbled on decryption"));
955 crReturn(0);
956 }
957
958 /*
959 * This enables us to deduce the payload length.
960 */
961 st->payload = st->len - st->pad - 1;
962
963 ssh->pktin.length = st->payload + 5;
964
965 /*
966 * So now we can work out the total packet length.
967 */
968 st->packetlen = st->len + 4;
969 st->maclen = ssh->scmac ? ssh->scmac->len : 0;
970
971 /*
972 * Adjust memory allocation if packet is too big.
973 */
974 if (ssh->pktin.maxlen < st->packetlen + st->maclen) {
975 ssh->pktin.maxlen = st->packetlen + st->maclen;
976 ssh->pktin.data = srealloc(ssh->pktin.data,
977 ssh->pktin.maxlen + APIEXTRA);
978 }
979
980 /*
981 * Read and decrypt the remainder of the packet.
982 */
983 for (st->i = st->cipherblk; st->i < st->packetlen + st->maclen;
984 st->i++) {
985 while ((*datalen) == 0)
986 crReturn(st->packetlen + st->maclen - st->i);
987 ssh->pktin.data[st->i] = *(*data)++;
988 (*datalen)--;
989 }
990 /* Decrypt everything _except_ the MAC. */
991 if (ssh->sccipher)
992 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
993 ssh->pktin.data + st->cipherblk,
994 st->packetlen - st->cipherblk);
995
996 /*
997 * Check the MAC.
998 */
999 if (ssh->scmac
1000 && !ssh->scmac->verify(ssh->sc_mac_ctx, ssh->pktin.data, st->len + 4,
1001 st->incoming_sequence)) {
1002 bombout((ssh,"Incorrect MAC received on packet"));
1003 crReturn(0);
1004 }
1005 st->incoming_sequence++; /* whether or not we MACed */
1006
1007 /*
1008 * Decompress packet payload.
1009 */
1010 {
1011 unsigned char *newpayload;
1012 int newlen;
1013 if (ssh->sccomp &&
1014 ssh->sccomp->decompress(ssh->sc_comp_ctx,
1015 ssh->pktin.data + 5, ssh->pktin.length - 5,
1016 &newpayload, &newlen)) {
1017 if (ssh->pktin.maxlen < newlen + 5) {
1018 ssh->pktin.maxlen = newlen + 5;
1019 ssh->pktin.data = srealloc(ssh->pktin.data,
1020 ssh->pktin.maxlen + APIEXTRA);
1021 }
1022 ssh->pktin.length = 5 + newlen;
1023 memcpy(ssh->pktin.data + 5, newpayload, newlen);
1024 sfree(newpayload);
1025 }
1026 }
1027
1028 ssh->pktin.savedpos = 6;
1029 ssh->pktin.type = ssh->pktin.data[5];
1030
1031 if (ssh->logctx)
1032 log_packet(ssh->logctx, PKT_INCOMING, ssh->pktin.type,
1033 ssh2_pkt_type(ssh->pkt_ctx, ssh->pktin.type),
1034 ssh->pktin.data+6, ssh->pktin.length-6);
1035
1036 switch (ssh->pktin.type) {
1037 /*
1038 * These packets we must handle instantly.
1039 */
1040 case SSH2_MSG_DISCONNECT:
1041 {
1042 /* log reason code in disconnect message */
1043 char *buf;
1044 int nowlen;
1045 int reason = GET_32BIT(ssh->pktin.data + 6);
1046 unsigned msglen = GET_32BIT(ssh->pktin.data + 10);
1047
1048 if (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) {
1049 buf = dupprintf("Received disconnect message (%s)",
1050 ssh2_disconnect_reasons[reason]);
1051 } else {
1052 buf = dupprintf("Received disconnect message (unknown"
1053 " type %d)", reason);
1054 }
1055 logevent(buf);
1056 sfree(buf);
1057 buf = dupprintf("Disconnection message text: %n%.*s",
1058 &nowlen, msglen, ssh->pktin.data + 14);
1059 logevent(buf);
1060 bombout((ssh,"Server sent disconnect message\ntype %d (%s):\n\"%s\"",
1061 reason,
1062 (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) ?
1063 ssh2_disconnect_reasons[reason] : "unknown",
1064 buf+nowlen));
1065 sfree(buf);
1066 crReturn(0);
1067 }
1068 break;
1069 case SSH2_MSG_IGNORE:
1070 goto next_packet;
1071 case SSH2_MSG_DEBUG:
1072 {
1073 /* log the debug message */
1074 char buf[512];
1075 /* int display = ssh->pktin.body[6]; */
1076 int stringlen = GET_32BIT(ssh->pktin.data+7);
1077 int prefix;
1078 strcpy(buf, "Remote debug message: ");
1079 prefix = strlen(buf);
1080 if (stringlen > (int)(sizeof(buf)-prefix-1))
1081 stringlen = sizeof(buf)-prefix-1;
1082 memcpy(buf + prefix, ssh->pktin.data + 11, stringlen);
1083 buf[prefix + stringlen] = '\0';
1084 logevent(buf);
1085 }
1086 goto next_packet; /* FIXME: print the debug message */
1087
1088 /*
1089 * These packets we need do nothing about here.
1090 */
1091 case SSH2_MSG_UNIMPLEMENTED:
1092 case SSH2_MSG_SERVICE_REQUEST:
1093 case SSH2_MSG_SERVICE_ACCEPT:
1094 case SSH2_MSG_KEXINIT:
1095 case SSH2_MSG_NEWKEYS:
1096 case SSH2_MSG_KEXDH_INIT:
1097 case SSH2_MSG_KEXDH_REPLY:
1098 /* case SSH2_MSG_KEX_DH_GEX_REQUEST: duplicate case value */
1099 /* case SSH2_MSG_KEX_DH_GEX_GROUP: duplicate case value */
1100 case SSH2_MSG_KEX_DH_GEX_INIT:
1101 case SSH2_MSG_KEX_DH_GEX_REPLY:
1102 case SSH2_MSG_USERAUTH_REQUEST:
1103 case SSH2_MSG_USERAUTH_FAILURE:
1104 case SSH2_MSG_USERAUTH_SUCCESS:
1105 case SSH2_MSG_USERAUTH_BANNER:
1106 case SSH2_MSG_USERAUTH_PK_OK:
1107 /* case SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ: duplicate case value */
1108 /* case SSH2_MSG_USERAUTH_INFO_REQUEST: duplicate case value */
1109 case SSH2_MSG_USERAUTH_INFO_RESPONSE:
1110 case SSH2_MSG_GLOBAL_REQUEST:
1111 case SSH2_MSG_REQUEST_SUCCESS:
1112 case SSH2_MSG_REQUEST_FAILURE:
1113 case SSH2_MSG_CHANNEL_OPEN:
1114 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION:
1115 case SSH2_MSG_CHANNEL_OPEN_FAILURE:
1116 case SSH2_MSG_CHANNEL_WINDOW_ADJUST:
1117 case SSH2_MSG_CHANNEL_DATA:
1118 case SSH2_MSG_CHANNEL_EXTENDED_DATA:
1119 case SSH2_MSG_CHANNEL_EOF:
1120 case SSH2_MSG_CHANNEL_CLOSE:
1121 case SSH2_MSG_CHANNEL_REQUEST:
1122 case SSH2_MSG_CHANNEL_SUCCESS:
1123 case SSH2_MSG_CHANNEL_FAILURE:
1124 break;
1125
1126 /*
1127 * For anything else we send SSH2_MSG_UNIMPLEMENTED.
1128 */
1129 default:
1130 ssh2_pkt_init(ssh, SSH2_MSG_UNIMPLEMENTED);
1131 ssh2_pkt_adduint32(ssh, st->incoming_sequence - 1);
1132 ssh2_pkt_send(ssh);
1133 break;
1134 }
1135
1136 crFinish(0);
1137 }
1138
1139 static void ssh1_pktout_size(Ssh ssh, int len)
1140 {
1141 int pad, biglen;
1142
1143 len += 5; /* type and CRC */
1144 pad = 8 - (len % 8);
1145 biglen = len + pad;
1146
1147 ssh->pktout.length = len - 5;
1148 if (ssh->pktout.maxlen < biglen) {
1149 ssh->pktout.maxlen = biglen;
1150 #ifdef MSCRYPTOAPI
1151 /* Allocate enough buffer space for extra block
1152 * for MS CryptEncrypt() */
1153 ssh->pktout.data = srealloc(ssh->pktout.data, biglen + 12);
1154 #else
1155 ssh->pktout.data = srealloc(ssh->pktout.data, biglen + 4);
1156 #endif
1157 }
1158 ssh->pktout.body = ssh->pktout.data + 4 + pad + 1;
1159 }
1160
1161 static void s_wrpkt_start(Ssh ssh, int type, int len)
1162 {
1163 ssh1_pktout_size(ssh, len);
1164 ssh->pktout.type = type;
1165 }
1166
1167 static int s_wrpkt_prepare(Ssh ssh)
1168 {
1169 int pad, len, biglen, i;
1170 unsigned long crc;
1171
1172 ssh->pktout.body[-1] = ssh->pktout.type;
1173
1174 if (ssh->logctx)
1175 log_packet(ssh->logctx, PKT_OUTGOING, ssh->pktout.type,
1176 ssh1_pkt_type(ssh->pktout.type),
1177 ssh->pktout.body, ssh->pktout.length);
1178
1179 if (ssh->v1_compressing) {
1180 unsigned char *compblk;
1181 int complen;
1182 zlib_compress_block(ssh->cs_comp_ctx,
1183 ssh->pktout.body - 1, ssh->pktout.length + 1,
1184 &compblk, &complen);
1185 ssh1_pktout_size(ssh, complen - 1);
1186 memcpy(ssh->pktout.body - 1, compblk, complen);
1187 sfree(compblk);
1188 }
1189
1190 len = ssh->pktout.length + 5; /* type and CRC */
1191 pad = 8 - (len % 8);
1192 biglen = len + pad;
1193
1194 for (i = 0; i < pad; i++)
1195 ssh->pktout.data[i + 4] = random_byte();
1196 crc = crc32(ssh->pktout.data + 4, biglen - 4);
1197 PUT_32BIT(ssh->pktout.data + biglen, crc);
1198 PUT_32BIT(ssh->pktout.data, len);
1199
1200 if (ssh->cipher)
1201 ssh->cipher->encrypt(ssh->v1_cipher_ctx, ssh->pktout.data + 4, biglen);
1202
1203 return biglen + 4;
1204 }
1205
1206 static void s_wrpkt(Ssh ssh)
1207 {
1208 int len, backlog;
1209 len = s_wrpkt_prepare(ssh);
1210 backlog = sk_write(ssh->s, (char *)ssh->pktout.data, len);
1211 if (backlog > SSH_MAX_BACKLOG)
1212 ssh_throttle_all(ssh, 1, backlog);
1213 }
1214
1215 static void s_wrpkt_defer(Ssh ssh)
1216 {
1217 int len;
1218 len = s_wrpkt_prepare(ssh);
1219 if (ssh->deferred_len + len > ssh->deferred_size) {
1220 ssh->deferred_size = ssh->deferred_len + len + 128;
1221 ssh->deferred_send_data = srealloc(ssh->deferred_send_data,
1222 ssh->deferred_size);
1223 }
1224 memcpy(ssh->deferred_send_data + ssh->deferred_len, ssh->pktout.data, len);
1225 ssh->deferred_len += len;
1226 }
1227
1228 /*
1229 * Construct a packet with the specified contents.
1230 */
1231 static void construct_packet(Ssh ssh, int pkttype, va_list ap1, va_list ap2)
1232 {
1233 unsigned char *p, *argp, argchar;
1234 unsigned long argint;
1235 int pktlen, argtype, arglen;
1236 Bignum bn;
1237
1238 pktlen = 0;
1239 while ((argtype = va_arg(ap1, int)) != PKT_END) {
1240 switch (argtype) {
1241 case PKT_INT:
1242 (void) va_arg(ap1, int);
1243 pktlen += 4;
1244 break;
1245 case PKT_CHAR:
1246 (void) va_arg(ap1, int);
1247 pktlen++;
1248 break;
1249 case PKT_DATA:
1250 (void) va_arg(ap1, unsigned char *);
1251 arglen = va_arg(ap1, int);
1252 pktlen += arglen;
1253 break;
1254 case PKT_STR:
1255 argp = va_arg(ap1, unsigned char *);
1256 arglen = strlen((char *)argp);
1257 pktlen += 4 + arglen;
1258 break;
1259 case PKT_BIGNUM:
1260 bn = va_arg(ap1, Bignum);
1261 pktlen += ssh1_bignum_length(bn);
1262 break;
1263 default:
1264 assert(0);
1265 }
1266 }
1267
1268 s_wrpkt_start(ssh, pkttype, pktlen);
1269 p = ssh->pktout.body;
1270
1271 while ((argtype = va_arg(ap2, int)) != PKT_END) {
1272 switch (argtype) {
1273 case PKT_INT:
1274 argint = va_arg(ap2, int);
1275 PUT_32BIT(p, argint);
1276 p += 4;
1277 break;
1278 case PKT_CHAR:
1279 argchar = (unsigned char) va_arg(ap2, int);
1280 *p = argchar;
1281 p++;
1282 break;
1283 case PKT_DATA:
1284 argp = va_arg(ap2, unsigned char *);
1285 arglen = va_arg(ap2, int);
1286 memcpy(p, argp, arglen);
1287 p += arglen;
1288 break;
1289 case PKT_STR:
1290 argp = va_arg(ap2, unsigned char *);
1291 arglen = strlen((char *)argp);
1292 PUT_32BIT(p, arglen);
1293 memcpy(p + 4, argp, arglen);
1294 p += 4 + arglen;
1295 break;
1296 case PKT_BIGNUM:
1297 bn = va_arg(ap2, Bignum);
1298 p += ssh1_write_bignum(p, bn);
1299 break;
1300 }
1301 }
1302 }
1303
1304 static void send_packet(Ssh ssh, int pkttype, ...)
1305 {
1306 va_list ap1, ap2;
1307 va_start(ap1, pkttype);
1308 va_start(ap2, pkttype);
1309 construct_packet(ssh, pkttype, ap1, ap2);
1310 s_wrpkt(ssh);
1311 }
1312
1313 static void defer_packet(Ssh ssh, int pkttype, ...)
1314 {
1315 va_list ap1, ap2;
1316 va_start(ap1, pkttype);
1317 va_start(ap2, pkttype);
1318 construct_packet(ssh, pkttype, ap1, ap2);
1319 s_wrpkt_defer(ssh);
1320 }
1321
1322 static int ssh_versioncmp(char *a, char *b)
1323 {
1324 char *ae, *be;
1325 unsigned long av, bv;
1326
1327 av = strtoul(a, &ae, 10);
1328 bv = strtoul(b, &be, 10);
1329 if (av != bv)
1330 return (av < bv ? -1 : +1);
1331 if (*ae == '.')
1332 ae++;
1333 if (*be == '.')
1334 be++;
1335 av = strtoul(ae, &ae, 10);
1336 bv = strtoul(be, &be, 10);
1337 if (av != bv)
1338 return (av < bv ? -1 : +1);
1339 return 0;
1340 }
1341
1342 /*
1343 * Utility routines for putting an SSH-protocol `string' and
1344 * `uint32' into a SHA state.
1345 */
1346 #include <stdio.h>
1347 static void sha_string(SHA_State * s, void *str, int len)
1348 {
1349 unsigned char lenblk[4];
1350 PUT_32BIT(lenblk, len);
1351 SHA_Bytes(s, lenblk, 4);
1352 SHA_Bytes(s, str, len);
1353 }
1354
1355 static void sha_uint32(SHA_State * s, unsigned i)
1356 {
1357 unsigned char intblk[4];
1358 PUT_32BIT(intblk, i);
1359 SHA_Bytes(s, intblk, 4);
1360 }
1361
1362 /*
1363 * SSH2 packet construction functions.
1364 */
1365 static void ssh2_pkt_ensure(Ssh ssh, int length)
1366 {
1367 if (ssh->pktout.maxlen < length) {
1368 ssh->pktout.maxlen = length + 256;
1369 ssh->pktout.data = srealloc(ssh->pktout.data,
1370 ssh->pktout.maxlen + APIEXTRA);
1371 if (!ssh->pktout.data)
1372 fatalbox("Out of memory");
1373 }
1374 }
1375 static void ssh2_pkt_adddata(Ssh ssh, void *data, int len)
1376 {
1377 ssh->pktout.length += len;
1378 ssh2_pkt_ensure(ssh, ssh->pktout.length);
1379 memcpy(ssh->pktout.data + ssh->pktout.length - len, data, len);
1380 }
1381 static void ssh2_pkt_addbyte(Ssh ssh, unsigned char byte)
1382 {
1383 ssh2_pkt_adddata(ssh, &byte, 1);
1384 }
1385 static void ssh2_pkt_init(Ssh ssh, int pkt_type)
1386 {
1387 ssh->pktout.length = 5;
1388 ssh2_pkt_addbyte(ssh, (unsigned char) pkt_type);
1389 }
1390 static void ssh2_pkt_addbool(Ssh ssh, unsigned char value)
1391 {
1392 ssh2_pkt_adddata(ssh, &value, 1);
1393 }
1394 static void ssh2_pkt_adduint32(Ssh ssh, unsigned long value)
1395 {
1396 unsigned char x[4];
1397 PUT_32BIT(x, value);
1398 ssh2_pkt_adddata(ssh, x, 4);
1399 }
1400 static void ssh2_pkt_addstring_start(Ssh ssh)
1401 {
1402 ssh2_pkt_adduint32(ssh, 0);
1403 ssh->pktout.savedpos = ssh->pktout.length;
1404 }
1405 static void ssh2_pkt_addstring_str(Ssh ssh, char *data)
1406 {
1407 ssh2_pkt_adddata(ssh, data, strlen(data));
1408 PUT_32BIT(ssh->pktout.data + ssh->pktout.savedpos - 4,
1409 ssh->pktout.length - ssh->pktout.savedpos);
1410 }
1411 static void ssh2_pkt_addstring_data(Ssh ssh, char *data, int len)
1412 {
1413 ssh2_pkt_adddata(ssh, data, len);
1414 PUT_32BIT(ssh->pktout.data + ssh->pktout.savedpos - 4,
1415 ssh->pktout.length - ssh->pktout.savedpos);
1416 }
1417 static void ssh2_pkt_addstring(Ssh ssh, char *data)
1418 {
1419 ssh2_pkt_addstring_start(ssh);
1420 ssh2_pkt_addstring_str(ssh, data);
1421 }
1422 static unsigned char *ssh2_mpint_fmt(Bignum b, int *len)
1423 {
1424 unsigned char *p;
1425 int i, n = (bignum_bitcount(b) + 7) / 8;
1426 p = smalloc(n + 1);
1427 if (!p)
1428 fatalbox("out of memory");
1429 p[0] = 0;
1430 for (i = 1; i <= n; i++)
1431 p[i] = bignum_byte(b, n - i);
1432 i = 0;
1433 while (i <= n && p[i] == 0 && (p[i + 1] & 0x80) == 0)
1434 i++;
1435 memmove(p, p + i, n + 1 - i);
1436 *len = n + 1 - i;
1437 return p;
1438 }
1439 static void ssh2_pkt_addmp(Ssh ssh, Bignum b)
1440 {
1441 unsigned char *p;
1442 int len;
1443 p = ssh2_mpint_fmt(b, &len);
1444 ssh2_pkt_addstring_start(ssh);
1445 ssh2_pkt_addstring_data(ssh, (char *)p, len);
1446 sfree(p);
1447 }
1448
1449 /*
1450 * Construct an SSH2 final-form packet: compress it, encrypt it,
1451 * put the MAC on it. Final packet, ready to be sent, is stored in
1452 * ssh->pktout.data. Total length is returned.
1453 */
1454 static int ssh2_pkt_construct(Ssh ssh)
1455 {
1456 int cipherblk, maclen, padding, i;
1457
1458 if (ssh->logctx)
1459 log_packet(ssh->logctx, PKT_OUTGOING, ssh->pktout.data[5],
1460 ssh2_pkt_type(ssh->pkt_ctx, ssh->pktout.data[5]),
1461 ssh->pktout.data + 6, ssh->pktout.length - 6);
1462
1463 /*
1464 * Compress packet payload.
1465 */
1466 {
1467 unsigned char *newpayload;
1468 int newlen;
1469 if (ssh->cscomp &&
1470 ssh->cscomp->compress(ssh->cs_comp_ctx, ssh->pktout.data + 5,
1471 ssh->pktout.length - 5,
1472 &newpayload, &newlen)) {
1473 ssh->pktout.length = 5;
1474 ssh2_pkt_adddata(ssh, newpayload, newlen);
1475 sfree(newpayload);
1476 }
1477 }
1478
1479 /*
1480 * Add padding. At least four bytes, and must also bring total
1481 * length (minus MAC) up to a multiple of the block size.
1482 */
1483 cipherblk = ssh->cscipher ? ssh->cscipher->blksize : 8; /* block size */
1484 cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */
1485 padding = 4;
1486 padding +=
1487 (cipherblk - (ssh->pktout.length + padding) % cipherblk) % cipherblk;
1488 maclen = ssh->csmac ? ssh->csmac->len : 0;
1489 ssh2_pkt_ensure(ssh, ssh->pktout.length + padding + maclen);
1490 ssh->pktout.data[4] = padding;
1491 for (i = 0; i < padding; i++)
1492 ssh->pktout.data[ssh->pktout.length + i] = random_byte();
1493 PUT_32BIT(ssh->pktout.data, ssh->pktout.length + padding - 4);
1494 if (ssh->csmac)
1495 ssh->csmac->generate(ssh->cs_mac_ctx, ssh->pktout.data,
1496 ssh->pktout.length + padding,
1497 ssh->v2_outgoing_sequence);
1498 ssh->v2_outgoing_sequence++; /* whether or not we MACed */
1499
1500 if (ssh->cscipher)
1501 ssh->cscipher->encrypt(ssh->cs_cipher_ctx,
1502 ssh->pktout.data, ssh->pktout.length + padding);
1503
1504 /* Ready-to-send packet starts at ssh->pktout.data. We return length. */
1505 return ssh->pktout.length + padding + maclen;
1506 }
1507
1508 /*
1509 * Construct and send an SSH2 packet immediately.
1510 */
1511 static void ssh2_pkt_send(Ssh ssh)
1512 {
1513 int len;
1514 int backlog;
1515 len = ssh2_pkt_construct(ssh);
1516 backlog = sk_write(ssh->s, (char *)ssh->pktout.data, len);
1517 if (backlog > SSH_MAX_BACKLOG)
1518 ssh_throttle_all(ssh, 1, backlog);
1519 }
1520
1521 /*
1522 * Construct an SSH2 packet and add it to a deferred data block.
1523 * Useful for sending multiple packets in a single sk_write() call,
1524 * to prevent a traffic-analysing listener from being able to work
1525 * out the length of any particular packet (such as the password
1526 * packet).
1527 *
1528 * Note that because SSH2 sequence-numbers its packets, this can
1529 * NOT be used as an m4-style `defer' allowing packets to be
1530 * constructed in one order and sent in another.
1531 */
1532 static void ssh2_pkt_defer(Ssh ssh)
1533 {
1534 int len = ssh2_pkt_construct(ssh);
1535 if (ssh->deferred_len + len > ssh->deferred_size) {
1536 ssh->deferred_size = ssh->deferred_len + len + 128;
1537 ssh->deferred_send_data = srealloc(ssh->deferred_send_data,
1538 ssh->deferred_size);
1539 }
1540 memcpy(ssh->deferred_send_data + ssh->deferred_len, ssh->pktout.data, len);
1541 ssh->deferred_len += len;
1542 }
1543
1544 /*
1545 * Send the whole deferred data block constructed by
1546 * ssh2_pkt_defer() or SSH1's defer_packet().
1547 */
1548 static void ssh_pkt_defersend(Ssh ssh)
1549 {
1550 int backlog;
1551 backlog = sk_write(ssh->s, (char *)ssh->deferred_send_data,
1552 ssh->deferred_len);
1553 ssh->deferred_len = ssh->deferred_size = 0;
1554 sfree(ssh->deferred_send_data);
1555 ssh->deferred_send_data = NULL;
1556 if (backlog > SSH_MAX_BACKLOG)
1557 ssh_throttle_all(ssh, 1, backlog);
1558 }
1559
1560 #if 0
1561 void bndebug(char *string, Bignum b)
1562 {
1563 unsigned char *p;
1564 int i, len;
1565 p = ssh2_mpint_fmt(b, &len);
1566 debug(("%s", string));
1567 for (i = 0; i < len; i++)
1568 debug((" %02x", p[i]));
1569 debug(("\n"));
1570 sfree(p);
1571 }
1572 #endif
1573
1574 static void sha_mpint(SHA_State * s, Bignum b)
1575 {
1576 unsigned char *p;
1577 int len;
1578 p = ssh2_mpint_fmt(b, &len);
1579 sha_string(s, p, len);
1580 sfree(p);
1581 }
1582
1583 /*
1584 * SSH2 packet decode functions.
1585 */
1586 static unsigned long ssh2_pkt_getuint32(Ssh ssh)
1587 {
1588 unsigned long value;
1589 if (ssh->pktin.length - ssh->pktin.savedpos < 4)
1590 return 0; /* arrgh, no way to decline (FIXME?) */
1591 value = GET_32BIT(ssh->pktin.data + ssh->pktin.savedpos);
1592 ssh->pktin.savedpos += 4;
1593 return value;
1594 }
1595 static int ssh2_pkt_getbool(Ssh ssh)
1596 {
1597 unsigned long value;
1598 if (ssh->pktin.length - ssh->pktin.savedpos < 1)
1599 return 0; /* arrgh, no way to decline (FIXME?) */
1600 value = ssh->pktin.data[ssh->pktin.savedpos] != 0;
1601 ssh->pktin.savedpos++;
1602 return value;
1603 }
1604 static void ssh2_pkt_getstring(Ssh ssh, char **p, int *length)
1605 {
1606 int len;
1607 *p = NULL;
1608 *length = 0;
1609 if (ssh->pktin.length - ssh->pktin.savedpos < 4)
1610 return;
1611 len = GET_32BIT(ssh->pktin.data + ssh->pktin.savedpos);
1612 if (len < 0)
1613 return;
1614 *length = len;
1615 ssh->pktin.savedpos += 4;
1616 if (ssh->pktin.length - ssh->pktin.savedpos < *length)
1617 return;
1618 *p = (char *)(ssh->pktin.data + ssh->pktin.savedpos);
1619 ssh->pktin.savedpos += *length;
1620 }
1621 static Bignum ssh2_pkt_getmp(Ssh ssh)
1622 {
1623 char *p;
1624 int length;
1625 Bignum b;
1626
1627 ssh2_pkt_getstring(ssh, &p, &length);
1628 if (!p)
1629 return NULL;
1630 if (p[0] & 0x80) {
1631 bombout((ssh,"internal error: Can't handle negative mpints"));
1632 return NULL;
1633 }
1634 b = bignum_from_bytes((unsigned char *)p, length);
1635 return b;
1636 }
1637
1638 /*
1639 * Helper function to add an SSH2 signature blob to a packet.
1640 * Expects to be shown the public key blob as well as the signature
1641 * blob. Normally works just like ssh2_pkt_addstring, but will
1642 * fiddle with the signature packet if necessary for
1643 * BUG_SSH2_RSA_PADDING.
1644 */
1645 static void ssh2_add_sigblob(Ssh ssh, void *pkblob_v, int pkblob_len,
1646 void *sigblob_v, int sigblob_len)
1647 {
1648 unsigned char *pkblob = (unsigned char *)pkblob_v;
1649 unsigned char *sigblob = (unsigned char *)sigblob_v;
1650
1651 /* dmemdump(pkblob, pkblob_len); */
1652 /* dmemdump(sigblob, sigblob_len); */
1653
1654 /*
1655 * See if this is in fact an ssh-rsa signature and a buggy
1656 * server; otherwise we can just do this the easy way.
1657 */
1658 if ((ssh->remote_bugs & BUG_SSH2_RSA_PADDING) &&
1659 (GET_32BIT(pkblob) == 7 && !memcmp(pkblob+4, "ssh-rsa", 7))) {
1660 int pos, len, siglen;
1661
1662 /*
1663 * Find the byte length of the modulus.
1664 */
1665
1666 pos = 4+7; /* skip over "ssh-rsa" */
1667 pos += 4 + GET_32BIT(pkblob+pos); /* skip over exponent */
1668 len = GET_32BIT(pkblob+pos); /* find length of modulus */
1669 pos += 4; /* find modulus itself */
1670 while (len > 0 && pkblob[pos] == 0)
1671 len--, pos++;
1672 /* debug(("modulus length is %d\n", len)); */
1673
1674 /*
1675 * Now find the signature integer.
1676 */
1677 pos = 4+7; /* skip over "ssh-rsa" */
1678 siglen = GET_32BIT(sigblob+pos);
1679 /* debug(("signature length is %d\n", siglen)); */
1680
1681 if (len != siglen) {
1682 unsigned char newlen[4];
1683 ssh2_pkt_addstring_start(ssh);
1684 ssh2_pkt_addstring_data(ssh, (char *)sigblob, pos);
1685 /* dmemdump(sigblob, pos); */
1686 pos += 4; /* point to start of actual sig */
1687 PUT_32BIT(newlen, len);
1688 ssh2_pkt_addstring_data(ssh, (char *)newlen, 4);
1689 /* dmemdump(newlen, 4); */
1690 newlen[0] = 0;
1691 while (len-- > siglen) {
1692 ssh2_pkt_addstring_data(ssh, (char *)newlen, 1);
1693 /* dmemdump(newlen, 1); */
1694 }
1695 ssh2_pkt_addstring_data(ssh, (char *)(sigblob+pos), siglen);
1696 /* dmemdump(sigblob+pos, siglen); */
1697 return;
1698 }
1699
1700 /* Otherwise fall through and do it the easy way. */
1701 }
1702
1703 ssh2_pkt_addstring_start(ssh);
1704 ssh2_pkt_addstring_data(ssh, (char *)sigblob, sigblob_len);
1705 }
1706
1707 /*
1708 * Examine the remote side's version string and compare it against
1709 * a list of known buggy implementations.
1710 */
1711 static void ssh_detect_bugs(Ssh ssh, char *vstring)
1712 {
1713 char *imp; /* pointer to implementation part */
1714 imp = vstring;
1715 imp += strcspn(imp, "-");
1716 if (*imp) imp++;
1717 imp += strcspn(imp, "-");
1718 if (*imp) imp++;
1719
1720 ssh->remote_bugs = 0;
1721
1722 if (ssh->cfg.sshbug_ignore1 == BUG_ON ||
1723 (ssh->cfg.sshbug_ignore1 == BUG_AUTO &&
1724 (!strcmp(imp, "1.2.18") || !strcmp(imp, "1.2.19") ||
1725 !strcmp(imp, "1.2.20") || !strcmp(imp, "1.2.21") ||
1726 !strcmp(imp, "1.2.22") || !strcmp(imp, "Cisco-1.25")))) {
1727 /*
1728 * These versions don't support SSH1_MSG_IGNORE, so we have
1729 * to use a different defence against password length
1730 * sniffing.
1731 */
1732 ssh->remote_bugs |= BUG_CHOKES_ON_SSH1_IGNORE;
1733 logevent("We believe remote version has SSH1 ignore bug");
1734 }
1735
1736 if (ssh->cfg.sshbug_plainpw1 == BUG_ON ||
1737 (ssh->cfg.sshbug_plainpw1 == BUG_AUTO &&
1738 (!strcmp(imp, "Cisco-1.25")))) {
1739 /*
1740 * These versions need a plain password sent; they can't
1741 * handle having a null and a random length of data after
1742 * the password.
1743 */
1744 ssh->remote_bugs |= BUG_NEEDS_SSH1_PLAIN_PASSWORD;
1745 logevent("We believe remote version needs a plain SSH1 password");
1746 }
1747
1748 if (ssh->cfg.sshbug_rsa1 == BUG_ON ||
1749 (ssh->cfg.sshbug_rsa1 == BUG_AUTO &&
1750 (!strcmp(imp, "Cisco-1.25")))) {
1751 /*
1752 * These versions apparently have no clue whatever about
1753 * RSA authentication and will panic and die if they see
1754 * an AUTH_RSA message.
1755 */
1756 ssh->remote_bugs |= BUG_CHOKES_ON_RSA;
1757 logevent("We believe remote version can't handle RSA authentication");
1758 }
1759
1760 if (ssh->cfg.sshbug_hmac2 == BUG_ON ||
1761 (ssh->cfg.sshbug_hmac2 == BUG_AUTO &&
1762 (wc_match("2.1.0*", imp) || wc_match("2.0.*", imp) ||
1763 wc_match("2.2.0*", imp) || wc_match("2.3.0*", imp) ||
1764 wc_match("2.1 *", imp)))) {
1765 /*
1766 * These versions have the HMAC bug.
1767 */
1768 ssh->remote_bugs |= BUG_SSH2_HMAC;
1769 logevent("We believe remote version has SSH2 HMAC bug");
1770 }
1771
1772 if (ssh->cfg.sshbug_derivekey2 == BUG_ON ||
1773 (ssh->cfg.sshbug_derivekey2 == BUG_AUTO &&
1774 (wc_match("2.0.0*", imp) || wc_match("2.0.1[01]*", imp) ))) {
1775 /*
1776 * These versions have the key-derivation bug (failing to
1777 * include the literal shared secret in the hashes that
1778 * generate the keys).
1779 */
1780 ssh->remote_bugs |= BUG_SSH2_DERIVEKEY;
1781 logevent("We believe remote version has SSH2 key-derivation bug");
1782 }
1783
1784 if (ssh->cfg.sshbug_rsapad2 == BUG_ON ||
1785 (ssh->cfg.sshbug_rsapad2 == BUG_AUTO &&
1786 (wc_match("OpenSSH_2.[5-9]*", imp) ||
1787 wc_match("OpenSSH_3.[0-2]*", imp)))) {
1788 /*
1789 * These versions have the SSH2 RSA padding bug.
1790 */
1791 ssh->remote_bugs |= BUG_SSH2_RSA_PADDING;
1792 logevent("We believe remote version has SSH2 RSA padding bug");
1793 }
1794
1795 if (ssh->cfg.sshbug_dhgex2 == BUG_ON) {
1796 /*
1797 * User specified the SSH2 DH GEX bug.
1798 */
1799 ssh->remote_bugs |= BUG_SSH2_DH_GEX;
1800 logevent("We believe remote version has SSH2 DH group exchange bug");
1801 }
1802 }
1803
1804 static int do_ssh_init(Ssh ssh, unsigned char c)
1805 {
1806 struct do_ssh_init_state {
1807 int vslen;
1808 char version[10];
1809 char *vstring;
1810 int vstrsize;
1811 int i;
1812 int proto1, proto2;
1813 };
1814 crState(do_ssh_init_state);
1815
1816 crBegin(ssh->do_ssh_init_crstate);
1817
1818 /* Search for the string "SSH-" in the input. */
1819 s->i = 0;
1820 while (1) {
1821 static const int transS[] = { 1, 2, 2, 1 };
1822 static const int transH[] = { 0, 0, 3, 0 };
1823 static const int transminus[] = { 0, 0, 0, -1 };
1824 if (c == 'S')
1825 s->i = transS[s->i];
1826 else if (c == 'H')
1827 s->i = transH[s->i];
1828 else if (c == '-')
1829 s->i = transminus[s->i];
1830 else
1831 s->i = 0;
1832 if (s->i < 0)
1833 break;
1834 crReturn(1); /* get another character */
1835 }
1836
1837 s->vstrsize = 16;
1838 s->vstring = smalloc(s->vstrsize);
1839 strcpy(s->vstring, "SSH-");
1840 s->vslen = 4;
1841 s->i = 0;
1842 while (1) {
1843 crReturn(1); /* get another char */
1844 if (s->vslen >= s->vstrsize - 1) {
1845 s->vstrsize += 16;
1846 s->vstring = srealloc(s->vstring, s->vstrsize);
1847 }
1848 s->vstring[s->vslen++] = c;
1849 if (s->i >= 0) {
1850 if (c == '-') {
1851 s->version[s->i] = '\0';
1852 s->i = -1;
1853 } else if (s->i < sizeof(s->version) - 1)
1854 s->version[s->i++] = c;
1855 } else if (c == '\012')
1856 break;
1857 }
1858
1859 ssh->agentfwd_enabled = FALSE;
1860 ssh->rdpkt2_state.incoming_sequence = 0;
1861
1862 s->vstring[s->vslen] = 0;
1863 s->vstring[strcspn(s->vstring, "\r\n")] = '\0';/* remove EOL chars */
1864 {
1865 char *vlog;
1866 vlog = smalloc(20 + s->vslen);
1867 sprintf(vlog, "Server version: %s", s->vstring);
1868 logevent(vlog);
1869 sfree(vlog);
1870 }
1871 ssh_detect_bugs(ssh, s->vstring);
1872
1873 /*
1874 * Decide which SSH protocol version to support.
1875 */
1876
1877 /* Anything strictly below "2.0" means protocol 1 is supported. */
1878 s->proto1 = ssh_versioncmp(s->version, "2.0") < 0;
1879 /* Anything greater or equal to "1.99" means protocol 2 is supported. */
1880 s->proto2 = ssh_versioncmp(s->version, "1.99") >= 0;
1881
1882 if (ssh->cfg.sshprot == 0 && !s->proto1) {
1883 bombout((ssh,"SSH protocol version 1 required by user but not provided by server"));
1884 crReturn(0);
1885 }
1886 if (ssh->cfg.sshprot == 3 && !s->proto2) {
1887 bombout((ssh,"SSH protocol version 2 required by user but not provided by server"));
1888 crReturn(0);
1889 }
1890
1891 if (s->proto2 && (ssh->cfg.sshprot >= 2 || !s->proto1)) {
1892 /*
1893 * Use v2 protocol.
1894 */
1895 char verstring[80], vlog[100];
1896 sprintf(verstring, "SSH-2.0-%s", sshver);
1897 SHA_Init(&ssh->exhashbase);
1898 /*
1899 * Hash our version string and their version string.
1900 */
1901 sha_string(&ssh->exhashbase, verstring, strlen(verstring));
1902 sha_string(&ssh->exhashbase, s->vstring, strcspn(s->vstring, "\r\n"));
1903 sprintf(vlog, "We claim version: %s", verstring);
1904 logevent(vlog);
1905 strcat(verstring, "\012");
1906 logevent("Using SSH protocol version 2");
1907 sk_write(ssh->s, verstring, strlen(verstring));
1908 ssh->protocol = ssh2_protocol;
1909 ssh->version = 2;
1910 ssh->s_rdpkt = ssh2_rdpkt;
1911 } else {
1912 /*
1913 * Use v1 protocol.
1914 */
1915 char verstring[80], vlog[100];
1916 sprintf(verstring, "SSH-%s-%s",
1917 (ssh_versioncmp(s->version, "1.5") <= 0 ? s->version : "1.5"),
1918 sshver);
1919 sprintf(vlog, "We claim version: %s", verstring);
1920 logevent(vlog);
1921 strcat(verstring, "\012");
1922
1923 logevent("Using SSH protocol version 1");
1924 sk_write(ssh->s, verstring, strlen(verstring));
1925 ssh->protocol = ssh1_protocol;
1926 ssh->version = 1;
1927 ssh->s_rdpkt = ssh1_rdpkt;
1928 }
1929 ssh->state = SSH_STATE_BEFORE_SIZE;
1930
1931 sfree(s->vstring);
1932
1933 crFinish(0);
1934 }
1935
1936 static void ssh_gotdata(Ssh ssh, unsigned char *data, int datalen)
1937 {
1938 crBegin(ssh->ssh_gotdata_crstate);
1939
1940 /*
1941 * To begin with, feed the characters one by one to the
1942 * protocol initialisation / selection function do_ssh_init().
1943 * When that returns 0, we're done with the initial greeting
1944 * exchange and can move on to packet discipline.
1945 */
1946 while (1) {
1947 int ret; /* need not be kept across crReturn */
1948 if (datalen == 0)
1949 crReturnV; /* more data please */
1950 ret = do_ssh_init(ssh, *data);
1951 data++;
1952 datalen--;
1953 if (ret == 0)
1954 break;
1955 }
1956
1957 /*
1958 * We emerge from that loop when the initial negotiation is
1959 * over and we have selected an s_rdpkt function. Now pass
1960 * everything to s_rdpkt, and then pass the resulting packets
1961 * to the proper protocol handler.
1962 */
1963 if (datalen == 0)
1964 crReturnV;
1965 while (1) {
1966 while (datalen > 0) {
1967 if (ssh->s_rdpkt(ssh, &data, &datalen) == 0) {
1968 if (ssh->state == SSH_STATE_CLOSED) {
1969 return;
1970 }
1971 ssh->protocol(ssh, NULL, 0, 1);
1972 if (ssh->state == SSH_STATE_CLOSED) {
1973 return;
1974 }
1975 }
1976 }
1977 crReturnV;
1978 }
1979 crFinishV;
1980 }
1981
1982 static int ssh_closing(Plug plug, char *error_msg, int error_code,
1983 int calling_back)
1984 {
1985 Ssh ssh = (Ssh) plug;
1986 ssh->state = SSH_STATE_CLOSED;
1987 if (ssh->s) {
1988 sk_close(ssh->s);
1989 ssh->s = NULL;
1990 }
1991 if (error_msg) {
1992 /* A socket error has occurred. */
1993 logevent(error_msg);
1994 connection_fatal(ssh->frontend, error_msg);
1995 } else {
1996 /* Otherwise, the remote side closed the connection normally. */
1997 }
1998 return 0;
1999 }
2000
2001 static int ssh_receive(Plug plug, int urgent, char *data, int len)
2002 {
2003 Ssh ssh = (Ssh) plug;
2004 ssh_gotdata(ssh, (unsigned char *)data, len);
2005 if (ssh->state == SSH_STATE_CLOSED) {
2006 if (ssh->s) {
2007 sk_close(ssh->s);
2008 ssh->s = NULL;
2009 }
2010 return 0;
2011 }
2012 return 1;
2013 }
2014
2015 static void ssh_sent(Plug plug, int bufsize)
2016 {
2017 Ssh ssh = (Ssh) plug;
2018 /*
2019 * If the send backlog on the SSH socket itself clears, we
2020 * should unthrottle the whole world if it was throttled.
2021 */
2022 if (bufsize < SSH_MAX_BACKLOG)
2023 ssh_throttle_all(ssh, 0, bufsize);
2024 }
2025
2026 /*
2027 * Connect to specified host and port.
2028 * Returns an error message, or NULL on success.
2029 * Also places the canonical host name into `realhost'. It must be
2030 * freed by the caller.
2031 */
2032 static char *connect_to_host(Ssh ssh, char *host, int port,
2033 char **realhost, int nodelay)
2034 {
2035 static const struct plug_function_table fn_table = {
2036 ssh_closing,
2037 ssh_receive,
2038 ssh_sent,
2039 NULL
2040 };
2041
2042 SockAddr addr;
2043 char *err;
2044
2045 ssh->savedhost = smalloc(1 + strlen(host));
2046 if (!ssh->savedhost)
2047 fatalbox("Out of memory");
2048 strcpy(ssh->savedhost, host);
2049
2050 if (port < 0)
2051 port = 22; /* default ssh port */
2052 ssh->savedport = port;
2053
2054 /*
2055 * Try to find host.
2056 */
2057 logeventf(ssh, "Looking up host \"%s\"", host);
2058 addr = name_lookup(host, port, realhost, &ssh->cfg);
2059 if ((err = sk_addr_error(addr)) != NULL)
2060 return err;
2061
2062 /*
2063 * Open socket.
2064 */
2065 {
2066 char addrbuf[100];
2067 sk_getaddr(addr, addrbuf, 100);
2068 logeventf(ssh, "Connecting to %s port %d", addrbuf, port);
2069 }
2070 ssh->fn = &fn_table;
2071 ssh->s = new_connection(addr, *realhost, port,
2072 0, 1, nodelay, (Plug) ssh, &ssh->cfg);
2073 if ((err = sk_socket_error(ssh->s)) != NULL) {
2074 ssh->s = NULL;
2075 return err;
2076 }
2077
2078 return NULL;
2079 }
2080
2081 /*
2082 * Throttle or unthrottle the SSH connection.
2083 */
2084 static void ssh1_throttle(Ssh ssh, int adjust)
2085 {
2086 int old_count = ssh->v1_throttle_count;
2087 ssh->v1_throttle_count += adjust;
2088 assert(ssh->v1_throttle_count >= 0);
2089 if (ssh->v1_throttle_count && !old_count) {
2090 sk_set_frozen(ssh->s, 1);
2091 } else if (!ssh->v1_throttle_count && old_count) {
2092 sk_set_frozen(ssh->s, 0);
2093 }
2094 }
2095
2096 /*
2097 * Throttle or unthrottle _all_ local data streams (for when sends
2098 * on the SSH connection itself back up).
2099 */
2100 static void ssh_throttle_all(Ssh ssh, int enable, int bufsize)
2101 {
2102 int i;
2103 struct ssh_channel *c;
2104
2105 if (enable == ssh->throttled_all)
2106 return;
2107 ssh->throttled_all = enable;
2108 ssh->overall_bufsize = bufsize;
2109 if (!ssh->channels)
2110 return;
2111 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
2112 switch (c->type) {
2113 case CHAN_MAINSESSION:
2114 /*
2115 * This is treated separately, outside the switch.
2116 */
2117 break;
2118 case CHAN_X11:
2119 x11_override_throttle(c->u.x11.s, enable);
2120 break;
2121 case CHAN_AGENT:
2122 /* Agent channels require no buffer management. */
2123 break;
2124 case CHAN_SOCKDATA:
2125 pfd_override_throttle(c->u.x11.s, enable);
2126 break;
2127 }
2128 }
2129 }
2130
2131 /*
2132 * Username and password input, abstracted off into routines
2133 * reusable in several places - even between SSH1 and SSH2.
2134 */
2135
2136 /* Set up a username or password input loop on a given buffer. */
2137 static void setup_userpass_input(Ssh ssh, char *buffer, int buflen, int echo)
2138 {
2139 ssh->userpass_input_buffer = buffer;
2140 ssh->userpass_input_buflen = buflen;
2141 ssh->userpass_input_bufpos = 0;
2142 ssh->userpass_input_echo = echo;
2143 }
2144
2145 /*
2146 * Process some terminal data in the course of username/password
2147 * input. Returns >0 for success (line of input returned in
2148 * buffer), <0 for failure (user hit ^C/^D, bomb out and exit), 0
2149 * for inconclusive (keep waiting for more input please).
2150 */
2151 static int process_userpass_input(Ssh ssh, unsigned char *in, int inlen)
2152 {
2153 char c;
2154
2155 while (inlen--) {
2156 switch (c = *in++) {
2157 case 10:
2158 case 13:
2159 ssh->userpass_input_buffer[ssh->userpass_input_bufpos] = 0;
2160 ssh->userpass_input_buffer[ssh->userpass_input_buflen-1] = 0;
2161 return +1;
2162 break;
2163 case 8:
2164 case 127:
2165 if (ssh->userpass_input_bufpos > 0) {
2166 if (ssh->userpass_input_echo)
2167 c_write_str(ssh, "\b \b");
2168 ssh->userpass_input_bufpos--;
2169 }
2170 break;
2171 case 21:
2172 case 27:
2173 while (ssh->userpass_input_bufpos > 0) {
2174 if (ssh->userpass_input_echo)
2175 c_write_str(ssh, "\b \b");
2176 ssh->userpass_input_bufpos--;
2177 }
2178 break;
2179 case 3:
2180 case 4:
2181 return -1;
2182 break;
2183 default:
2184 if (((c >= ' ' && c <= '~') ||
2185 ((unsigned char) c >= 160))
2186 && ssh->userpass_input_bufpos < ssh->userpass_input_buflen-1) {
2187 ssh->userpass_input_buffer[ssh->userpass_input_bufpos++] = c;
2188 if (ssh->userpass_input_echo)
2189 c_write(ssh, &c, 1);
2190 }
2191 break;
2192 }
2193 }
2194 return 0;
2195 }
2196
2197 /*
2198 * Handle the key exchange and user authentication phases.
2199 */
2200 static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
2201 {
2202 int i, j;
2203 unsigned char cookie[8];
2204 struct RSAKey servkey, hostkey;
2205 struct MD5Context md5c;
2206 struct do_ssh1_login_state {
2207 int len;
2208 unsigned char *rsabuf, *keystr1, *keystr2;
2209 unsigned long supported_ciphers_mask, supported_auths_mask;
2210 int tried_publickey, tried_agent;
2211 int tis_auth_refused, ccard_auth_refused;
2212 unsigned char session_id[16];
2213 int cipher_type;
2214 char username[100];
2215 void *publickey_blob;
2216 int publickey_bloblen;
2217 char password[100];
2218 char prompt[200];
2219 int pos;
2220 char c;
2221 int pwpkt_type;
2222 unsigned char request[5], *response, *p;
2223 int responselen;
2224 int keyi, nkeys;
2225 int authed;
2226 struct RSAKey key;
2227 Bignum challenge;
2228 char *commentp;
2229 int commentlen;
2230 };
2231 crState(do_ssh1_login_state);
2232
2233 crBegin(ssh->do_ssh1_login_crstate);
2234
2235 if (!ispkt)
2236 crWaitUntil(ispkt);
2237
2238 if (ssh->pktin.type != SSH1_SMSG_PUBLIC_KEY) {
2239 bombout((ssh,"Public key packet not received"));
2240 crReturn(0);
2241 }
2242
2243 logevent("Received public keys");
2244
2245 memcpy(cookie, ssh->pktin.body, 8);
2246
2247 i = makekey(ssh->pktin.body + 8, &servkey, &s->keystr1, 0);
2248 j = makekey(ssh->pktin.body + 8 + i, &hostkey, &s->keystr2, 0);
2249
2250 /*
2251 * Log the host key fingerprint.
2252 */
2253 {
2254 char logmsg[80];
2255 logevent("Host key fingerprint is:");
2256 strcpy(logmsg, " ");
2257 hostkey.comment = NULL;
2258 rsa_fingerprint(logmsg + strlen(logmsg),
2259 sizeof(logmsg) - strlen(logmsg), &hostkey);
2260 logevent(logmsg);
2261 }
2262
2263 ssh->v1_remote_protoflags = GET_32BIT(ssh->pktin.body + 8 + i + j);
2264 s->supported_ciphers_mask = GET_32BIT(ssh->pktin.body + 12 + i + j);
2265 s->supported_auths_mask = GET_32BIT(ssh->pktin.body + 16 + i + j);
2266
2267 ssh->v1_local_protoflags =
2268 ssh->v1_remote_protoflags & SSH1_PROTOFLAGS_SUPPORTED;
2269 ssh->v1_local_protoflags |= SSH1_PROTOFLAG_SCREEN_NUMBER;
2270
2271 MD5Init(&md5c);
2272 MD5Update(&md5c, s->keystr2, hostkey.bytes);
2273 MD5Update(&md5c, s->keystr1, servkey.bytes);
2274 MD5Update(&md5c, ssh->pktin.body, 8);
2275 MD5Final(s->session_id, &md5c);
2276
2277 for (i = 0; i < 32; i++)
2278 ssh->session_key[i] = random_byte();
2279
2280 s->len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes);
2281
2282 s->rsabuf = smalloc(s->len);
2283 if (!s->rsabuf)
2284 fatalbox("Out of memory");
2285
2286 /*
2287 * Verify the host key.
2288 */
2289 {
2290 /*
2291 * First format the key into a string.
2292 */
2293 int len = rsastr_len(&hostkey);
2294 char fingerprint[100];
2295 char *keystr = smalloc(len);
2296 if (!keystr)
2297 fatalbox("Out of memory");
2298 rsastr_fmt(keystr, &hostkey);
2299 rsa_fingerprint(fingerprint, sizeof(fingerprint), &hostkey);
2300 verify_ssh_host_key(ssh->frontend,
2301 ssh->savedhost, ssh->savedport, "rsa", keystr,
2302 fingerprint);
2303 sfree(keystr);
2304 }
2305
2306 for (i = 0; i < 32; i++) {
2307 s->rsabuf[i] = ssh->session_key[i];
2308 if (i < 16)
2309 s->rsabuf[i] ^= s->session_id[i];
2310 }
2311
2312 if (hostkey.bytes > servkey.bytes) {
2313 rsaencrypt(s->rsabuf, 32, &servkey);
2314 rsaencrypt(s->rsabuf, servkey.bytes, &hostkey);
2315 } else {
2316 rsaencrypt(s->rsabuf, 32, &hostkey);
2317 rsaencrypt(s->rsabuf, hostkey.bytes, &servkey);
2318 }
2319
2320 logevent("Encrypted session key");
2321
2322 {
2323 int cipher_chosen = 0, warn = 0;
2324 char *cipher_string = NULL;
2325 int i;
2326 for (i = 0; !cipher_chosen && i < CIPHER_MAX; i++) {
2327 int next_cipher = ssh->cfg.ssh_cipherlist[i];
2328 if (next_cipher == CIPHER_WARN) {
2329 /* If/when we choose a cipher, warn about it */
2330 warn = 1;
2331 } else if (next_cipher == CIPHER_AES) {
2332 /* XXX Probably don't need to mention this. */
2333 logevent("AES not supported in SSH1, skipping");
2334 } else {
2335 switch (next_cipher) {
2336 case CIPHER_3DES: s->cipher_type = SSH_CIPHER_3DES;
2337 cipher_string = "3DES"; break;
2338 case CIPHER_BLOWFISH: s->cipher_type = SSH_CIPHER_BLOWFISH;
2339 cipher_string = "Blowfish"; break;
2340 case CIPHER_DES: s->cipher_type = SSH_CIPHER_DES;
2341 cipher_string = "single-DES"; break;
2342 }
2343 if (s->supported_ciphers_mask & (1 << s->cipher_type))
2344 cipher_chosen = 1;
2345 }
2346 }
2347 if (!cipher_chosen) {
2348 if ((s->supported_ciphers_mask & (1 << SSH_CIPHER_3DES)) == 0)
2349 bombout((ssh,"Server violates SSH 1 protocol by not "
2350 "supporting 3DES encryption"));
2351 else
2352 /* shouldn't happen */
2353 bombout((ssh,"No supported ciphers found"));
2354 crReturn(0);
2355 }
2356
2357 /* Warn about chosen cipher if necessary. */
2358 if (warn)
2359 askcipher(ssh->frontend, cipher_string, 0);
2360 }
2361
2362 switch (s->cipher_type) {
2363 case SSH_CIPHER_3DES:
2364 logevent("Using 3DES encryption");
2365 break;
2366 case SSH_CIPHER_DES:
2367 logevent("Using single-DES encryption");
2368 break;
2369 case SSH_CIPHER_BLOWFISH:
2370 logevent("Using Blowfish encryption");
2371 break;
2372 }
2373
2374 send_packet(ssh, SSH1_CMSG_SESSION_KEY,
2375 PKT_CHAR, s->cipher_type,
2376 PKT_DATA, cookie, 8,
2377 PKT_CHAR, (s->len * 8) >> 8, PKT_CHAR, (s->len * 8) & 0xFF,
2378 PKT_DATA, s->rsabuf, s->len,
2379 PKT_INT, ssh->v1_local_protoflags, PKT_END);
2380
2381 logevent("Trying to enable encryption...");
2382
2383 sfree(s->rsabuf);
2384
2385 ssh->cipher = (s->cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 :
2386 s->cipher_type == SSH_CIPHER_DES ? &ssh_des :
2387 &ssh_3des);
2388 ssh->v1_cipher_ctx = ssh->cipher->make_context();
2389 ssh->cipher->sesskey(ssh->v1_cipher_ctx, ssh->session_key);
2390 logeventf(ssh, "Initialised %s encryption", ssh->cipher->text_name);
2391
2392 ssh->crcda_ctx = crcda_make_context();
2393 logevent("Installing CRC compensation attack detector");
2394
2395 crWaitUntil(ispkt);
2396
2397 if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
2398 bombout((ssh,"Encryption not successfully enabled"));
2399 crReturn(0);
2400 }
2401
2402 logevent("Successfully started encryption");
2403
2404 fflush(stdout);
2405 {
2406 if ((flags & FLAG_INTERACTIVE) && !*ssh->cfg.username) {
2407 if (ssh_get_line && !ssh_getline_pw_only) {
2408 if (!ssh_get_line("login as: ",
2409 s->username, sizeof(s->username), FALSE)) {
2410 /*
2411 * get_line failed to get a username.
2412 * Terminate.
2413 */
2414 logevent("No username provided. Abandoning session.");
2415 ssh->state = SSH_STATE_CLOSED;
2416 crReturn(1);
2417 }
2418 } else {
2419 int ret; /* need not be kept over crReturn */
2420 c_write_str(ssh, "login as: ");
2421 ssh->send_ok = 1;
2422
2423 setup_userpass_input(ssh, s->username, sizeof(s->username), 1);
2424 do {
2425 crWaitUntil(!ispkt);
2426 ret = process_userpass_input(ssh, in, inlen);
2427 } while (ret == 0);
2428 if (ret < 0)
2429 cleanup_exit(0);
2430 c_write_str(ssh, "\r\n");
2431 }
2432 } else {
2433 strncpy(s->username, ssh->cfg.username, sizeof(s->username));
2434 s->username[sizeof(s->username)-1] = '\0';
2435 }
2436
2437 send_packet(ssh, SSH1_CMSG_USER, PKT_STR, s->username, PKT_END);
2438 {
2439 char userlog[22 + sizeof(s->username)];
2440 sprintf(userlog, "Sent username \"%s\"", s->username);
2441 logevent(userlog);
2442 if (flags & FLAG_INTERACTIVE &&
2443 (!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) {
2444 strcat(userlog, "\r\n");
2445 c_write_str(ssh, userlog);
2446 }
2447 }
2448 }
2449
2450 crWaitUntil(ispkt);
2451
2452 if ((ssh->remote_bugs & BUG_CHOKES_ON_RSA)) {
2453 /* We must not attempt PK auth. Pretend we've already tried it. */
2454 s->tried_publickey = s->tried_agent = 1;
2455 } else {
2456 s->tried_publickey = s->tried_agent = 0;
2457 }
2458 s->tis_auth_refused = s->ccard_auth_refused = 0;
2459 /* Load the public half of ssh->cfg.keyfile so we notice if it's in Pageant */
2460 if (*ssh->cfg.keyfile) {
2461 if (!rsakey_pubblob(ssh->cfg.keyfile,
2462 &s->publickey_blob, &s->publickey_bloblen))
2463 s->publickey_blob = NULL;
2464 } else
2465 s->publickey_blob = NULL;
2466
2467 while (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2468 s->pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
2469
2470 if (agent_exists() && !s->tried_agent) {
2471 /*
2472 * Attempt RSA authentication using Pageant.
2473 */
2474 void *r;
2475
2476 s->authed = FALSE;
2477 s->tried_agent = 1;
2478 logevent("Pageant is running. Requesting keys.");
2479
2480 /* Request the keys held by the agent. */
2481 PUT_32BIT(s->request, 1);
2482 s->request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES;
2483 agent_query(s->request, 5, &r, &s->responselen);
2484 s->response = (unsigned char *) r;
2485 if (s->response && s->responselen >= 5 &&
2486 s->response[4] == SSH1_AGENT_RSA_IDENTITIES_ANSWER) {
2487 s->p = s->response + 5;
2488 s->nkeys = GET_32BIT(s->p);
2489 s->p += 4;
2490 {
2491 char buf[64];
2492 sprintf(buf, "Pageant has %d SSH1 keys", s->nkeys);
2493 logevent(buf);
2494 }
2495 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
2496 {
2497 char buf[64];
2498 sprintf(buf, "Trying Pageant key #%d", s->keyi);
2499 logevent(buf);
2500 }
2501 if (s->publickey_blob &&
2502 !memcmp(s->p, s->publickey_blob,
2503 s->publickey_bloblen)) {
2504 logevent("This key matches configured key file");
2505 s->tried_publickey = 1;
2506 }
2507 s->p += 4;
2508 s->p += ssh1_read_bignum(s->p, &s->key.exponent);
2509 s->p += ssh1_read_bignum(s->p, &s->key.modulus);
2510 s->commentlen = GET_32BIT(s->p);
2511 s->p += 4;
2512 s->commentp = (char *)s->p;
2513 s->p += s->commentlen;
2514 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
2515 PKT_BIGNUM, s->key.modulus, PKT_END);
2516 crWaitUntil(ispkt);
2517 if (ssh->pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
2518 logevent("Key refused");
2519 continue;
2520 }
2521 logevent("Received RSA challenge");
2522 ssh1_read_bignum(ssh->pktin.body, &s->challenge);
2523 {
2524 char *agentreq, *q, *ret;
2525 void *vret;
2526 int len, retlen;
2527 len = 1 + 4; /* message type, bit count */
2528 len += ssh1_bignum_length(s->key.exponent);
2529 len += ssh1_bignum_length(s->key.modulus);
2530 len += ssh1_bignum_length(s->challenge);
2531 len += 16; /* session id */
2532 len += 4; /* response format */
2533 agentreq = smalloc(4 + len);
2534 PUT_32BIT(agentreq, len);
2535 q = agentreq + 4;
2536 *q++ = SSH1_AGENTC_RSA_CHALLENGE;
2537 PUT_32BIT(q, bignum_bitcount(s->key.modulus));
2538 q += 4;
2539 q += ssh1_write_bignum(q, s->key.exponent);
2540 q += ssh1_write_bignum(q, s->key.modulus);
2541 q += ssh1_write_bignum(q, s->challenge);
2542 memcpy(q, s->session_id, 16);
2543 q += 16;
2544 PUT_32BIT(q, 1); /* response format */
2545 agent_query(agentreq, len + 4, &vret, &retlen);
2546 ret = vret;
2547 sfree(agentreq);
2548 if (ret) {
2549 if (ret[4] == SSH1_AGENT_RSA_RESPONSE) {
2550 logevent("Sending Pageant's response");
2551 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
2552 PKT_DATA, ret + 5, 16,
2553 PKT_END);
2554 sfree(ret);
2555 crWaitUntil(ispkt);
2556 if (ssh->pktin.type == SSH1_SMSG_SUCCESS) {
2557 logevent
2558 ("Pageant's response accepted");
2559 if (flags & FLAG_VERBOSE) {
2560 c_write_str(ssh, "Authenticated using"
2561 " RSA key \"");
2562 c_write(ssh, s->commentp,
2563 s->commentlen);
2564 c_write_str(ssh, "\" from agent\r\n");
2565 }
2566 s->authed = TRUE;
2567 } else
2568 logevent
2569 ("Pageant's response not accepted");
2570 } else {
2571 logevent
2572 ("Pageant failed to answer challenge");
2573 sfree(ret);
2574 }
2575 } else {
2576 logevent("No reply received from Pageant");
2577 }
2578 }
2579 freebn(s->key.exponent);
2580 freebn(s->key.modulus);
2581 freebn(s->challenge);
2582 if (s->authed)
2583 break;
2584 }
2585 }
2586 if (s->authed)
2587 break;
2588 }
2589 if (*ssh->cfg.keyfile && !s->tried_publickey)
2590 s->pwpkt_type = SSH1_CMSG_AUTH_RSA;
2591
2592 if (ssh->cfg.try_tis_auth &&
2593 (s->supported_auths_mask & (1 << SSH1_AUTH_TIS)) &&
2594 !s->tis_auth_refused) {
2595 s->pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
2596 logevent("Requested TIS authentication");
2597 send_packet(ssh, SSH1_CMSG_AUTH_TIS, PKT_END);
2598 crWaitUntil(ispkt);
2599 if (ssh->pktin.type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
2600 logevent("TIS authentication declined");
2601 if (flags & FLAG_INTERACTIVE)
2602 c_write_str(ssh, "TIS authentication refused.\r\n");
2603 s->tis_auth_refused = 1;
2604 continue;
2605 } else {
2606 int challengelen = GET_32BIT(ssh->pktin.body);
2607 logevent("Received TIS challenge");
2608 if (challengelen > sizeof(s->prompt) - 1)
2609 challengelen = sizeof(s->prompt) - 1;/* prevent overrun */
2610 memcpy(s->prompt, ssh->pktin.body + 4, challengelen);
2611 /* Prompt heuristic comes from OpenSSH */
2612 strncpy(s->prompt + challengelen,
2613 memchr(s->prompt, '\n', challengelen) ?
2614 "": "\r\nResponse: ",
2615 (sizeof s->prompt) - challengelen);
2616 s->prompt[(sizeof s->prompt) - 1] = '\0';
2617 }
2618 }
2619 if (ssh->cfg.try_tis_auth &&
2620 (s->supported_auths_mask & (1 << SSH1_AUTH_CCARD)) &&
2621 !s->ccard_auth_refused) {
2622 s->pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE;
2623 logevent("Requested CryptoCard authentication");
2624 send_packet(ssh, SSH1_CMSG_AUTH_CCARD, PKT_END);
2625 crWaitUntil(ispkt);
2626 if (ssh->pktin.type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
2627 logevent("CryptoCard authentication declined");
2628 c_write_str(ssh, "CryptoCard authentication refused.\r\n");
2629 s->ccard_auth_refused = 1;
2630 continue;
2631 } else {
2632 int challengelen = GET_32BIT(ssh->pktin.body);
2633 logevent("Received CryptoCard challenge");
2634 if (challengelen > sizeof(s->prompt) - 1)
2635 challengelen = sizeof(s->prompt) - 1;/* prevent overrun */
2636 memcpy(s->prompt, ssh->pktin.body + 4, challengelen);
2637 strncpy(s->prompt + challengelen,
2638 memchr(s->prompt, '\n', challengelen) ?
2639 "" : "\r\nResponse: ",
2640 sizeof(s->prompt) - challengelen);
2641 s->prompt[sizeof(s->prompt) - 1] = '\0';
2642 }
2643 }
2644 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
2645 sprintf(s->prompt, "%.90s@%.90s's password: ",
2646 s->username, ssh->savedhost);
2647 }
2648 if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) {
2649 char *comment = NULL;
2650 int type;
2651 char msgbuf[256];
2652 if (flags & FLAG_VERBOSE)
2653 c_write_str(ssh, "Trying public key authentication.\r\n");
2654 logeventf(ssh, "Trying public key \"%s\"", ssh->cfg.keyfile);
2655 type = key_type(ssh->cfg.keyfile);
2656 if (type != SSH_KEYTYPE_SSH1) {
2657 sprintf(msgbuf, "Key is of wrong type (%s)",
2658 key_type_to_str(type));
2659 logevent(msgbuf);
2660 c_write_str(ssh, msgbuf);
2661 c_write_str(ssh, "\r\n");
2662 s->tried_publickey = 1;
2663 continue;
2664 }
2665 if (!rsakey_encrypted(ssh->cfg.keyfile, &comment)) {
2666 if (flags & FLAG_VERBOSE)
2667 c_write_str(ssh, "No passphrase required.\r\n");
2668 goto tryauth;
2669 }
2670 sprintf(s->prompt, "Passphrase for key \"%.100s\": ", comment);
2671 sfree(comment);
2672 }
2673
2674 /*
2675 * Show password prompt, having first obtained it via a TIS
2676 * or CryptoCard exchange if we're doing TIS or CryptoCard
2677 * authentication.
2678 */
2679 if (ssh_get_line) {
2680 if (!ssh_get_line(s->prompt, s->password,
2681 sizeof(s->password), TRUE)) {
2682 /*
2683 * get_line failed to get a password (for example
2684 * because one was supplied on the command line
2685 * which has already failed to work). Terminate.
2686 */
2687 send_packet(ssh, SSH1_MSG_DISCONNECT,
2688 PKT_STR, "No more passwords available to try",
2689 PKT_END);
2690 logevent("Unable to authenticate");
2691 connection_fatal(ssh->frontend, "Unable to authenticate");
2692 ssh->state = SSH_STATE_CLOSED;
2693 crReturn(1);
2694 }
2695 } else {
2696 /* Prompt may have come from server. We've munged it a bit, so
2697 * we know it to be zero-terminated at least once. */
2698 int ret; /* need not be saved over crReturn */
2699 c_write_untrusted(ssh, s->prompt, strlen(s->prompt));
2700 s->pos = 0;
2701
2702 setup_userpass_input(ssh, s->password, sizeof(s->password), 0);
2703 do {
2704 crWaitUntil(!ispkt);
2705 ret = process_userpass_input(ssh, in, inlen);
2706 } while (ret == 0);
2707 if (ret < 0)
2708 cleanup_exit(0);
2709 c_write_str(ssh, "\r\n");
2710 }
2711
2712 tryauth:
2713 if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) {
2714 /*
2715 * Try public key authentication with the specified
2716 * key file.
2717 */
2718 s->tried_publickey = 1;
2719
2720 {
2721 int ret = loadrsakey(ssh->cfg.keyfile, &s->key, s->password);
2722 if (ret == 0) {
2723 c_write_str(ssh, "Couldn't load private key from ");
2724 c_write_str(ssh, ssh->cfg.keyfile);
2725 c_write_str(ssh, ".\r\n");
2726 continue; /* go and try password */
2727 }
2728 if (ret == -1) {
2729 c_write_str(ssh, "Wrong passphrase.\r\n");
2730 s->tried_publickey = 0;
2731 continue; /* try again */
2732 }
2733 }
2734
2735 /*
2736 * Send a public key attempt.
2737 */
2738 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
2739 PKT_BIGNUM, s->key.modulus, PKT_END);
2740
2741 crWaitUntil(ispkt);
2742 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2743 c_write_str(ssh, "Server refused our public key.\r\n");
2744 continue; /* go and try password */
2745 }
2746 if (ssh->pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
2747 bombout((ssh,"Bizarre response to offer of public key"));
2748 crReturn(0);
2749 }
2750
2751 {
2752 int i;
2753 unsigned char buffer[32];
2754 Bignum challenge, response;
2755
2756 ssh1_read_bignum(ssh->pktin.body, &challenge);
2757 response = rsadecrypt(challenge, &s->key);
2758 freebn(s->key.private_exponent);/* burn the evidence */
2759
2760 for (i = 0; i < 32; i++) {
2761 buffer[i] = bignum_byte(response, 31 - i);
2762 }
2763
2764 MD5Init(&md5c);
2765 MD5Update(&md5c, buffer, 32);
2766 MD5Update(&md5c, s->session_id, 16);
2767 MD5Final(buffer, &md5c);
2768
2769 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
2770 PKT_DATA, buffer, 16, PKT_END);
2771
2772 freebn(challenge);
2773 freebn(response);
2774 }
2775
2776 crWaitUntil(ispkt);
2777 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2778 if (flags & FLAG_VERBOSE)
2779 c_write_str(ssh, "Failed to authenticate with"
2780 " our public key.\r\n");
2781 continue; /* go and try password */
2782 } else if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
2783 bombout((ssh,"Bizarre response to RSA authentication response"));
2784 crReturn(0);
2785 }
2786
2787 break; /* we're through! */
2788 } else {
2789 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
2790 /*
2791 * Defence against traffic analysis: we send a
2792 * whole bunch of packets containing strings of
2793 * different lengths. One of these strings is the
2794 * password, in a SSH1_CMSG_AUTH_PASSWORD packet.
2795 * The others are all random data in
2796 * SSH1_MSG_IGNORE packets. This way a passive
2797 * listener can't tell which is the password, and
2798 * hence can't deduce the password length.
2799 *
2800 * Anybody with a password length greater than 16
2801 * bytes is going to have enough entropy in their
2802 * password that a listener won't find it _that_
2803 * much help to know how long it is. So what we'll
2804 * do is:
2805 *
2806 * - if password length < 16, we send 15 packets
2807 * containing string lengths 1 through 15
2808 *
2809 * - otherwise, we let N be the nearest multiple
2810 * of 8 below the password length, and send 8
2811 * packets containing string lengths N through
2812 * N+7. This won't obscure the order of
2813 * magnitude of the password length, but it will
2814 * introduce a bit of extra uncertainty.
2815 *
2816 * A few servers (the old 1.2.18 through 1.2.22)
2817 * can't deal with SSH1_MSG_IGNORE. For these
2818 * servers, we need an alternative defence. We make
2819 * use of the fact that the password is interpreted
2820 * as a C string: so we can append a NUL, then some
2821 * random data.
2822 *
2823 * One server (a Cisco one) can deal with neither
2824 * SSH1_MSG_IGNORE _nor_ a padded password string.
2825 * For this server we are left with no defences
2826 * against password length sniffing.
2827 */
2828 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE)) {
2829 /*
2830 * The server can deal with SSH1_MSG_IGNORE, so
2831 * we can use the primary defence.
2832 */
2833 int bottom, top, pwlen, i;
2834 char *randomstr;
2835
2836 pwlen = strlen(s->password);
2837 if (pwlen < 16) {
2838 bottom = 0; /* zero length passwords are OK! :-) */
2839 top = 15;
2840 } else {
2841 bottom = pwlen & ~7;
2842 top = bottom + 7;
2843 }
2844
2845 assert(pwlen >= bottom && pwlen <= top);
2846
2847 randomstr = smalloc(top + 1);
2848
2849 for (i = bottom; i <= top; i++) {
2850 if (i == pwlen)
2851 defer_packet(ssh, s->pwpkt_type,
2852 PKT_STR, s->password, PKT_END);
2853 else {
2854 for (j = 0; j < i; j++) {
2855 do {
2856 randomstr[j] = random_byte();
2857 } while (randomstr[j] == '\0');
2858 }
2859 randomstr[i] = '\0';
2860 defer_packet(ssh, SSH1_MSG_IGNORE,
2861 PKT_STR, randomstr, PKT_END);
2862 }
2863 }
2864 logevent("Sending password with camouflage packets");
2865 ssh_pkt_defersend(ssh);
2866 }
2867 else if (!(ssh->remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) {
2868 /*
2869 * The server can't deal with SSH1_MSG_IGNORE
2870 * but can deal with padded passwords, so we
2871 * can use the secondary defence.
2872 */
2873 char string[64];
2874 char *ss;
2875 int len;
2876
2877 len = strlen(s->password);
2878 if (len < sizeof(string)) {
2879 ss = string;
2880 strcpy(string, s->password);
2881 len++; /* cover the zero byte */
2882 while (len < sizeof(string)) {
2883 string[len++] = (char) random_byte();
2884 }
2885 } else {
2886 ss = s->password;
2887 }
2888 logevent("Sending length-padded password");
2889 send_packet(ssh, s->pwpkt_type, PKT_INT, len,
2890 PKT_DATA, ss, len, PKT_END);
2891 } else {
2892 /*
2893 * The server has _both_
2894 * BUG_CHOKES_ON_SSH1_IGNORE and
2895 * BUG_NEEDS_SSH1_PLAIN_PASSWORD. There is
2896 * therefore nothing we can do.
2897 */
2898 int len;
2899 len = strlen(s->password);
2900 logevent("Sending unpadded password");
2901 send_packet(ssh, s->pwpkt_type, PKT_INT, len,
2902 PKT_DATA, s->password, len, PKT_END);
2903 }
2904 } else {
2905 send_packet(ssh, s->pwpkt_type, PKT_STR, s->password, PKT_END);
2906 }
2907 }
2908 logevent("Sent password");
2909 memset(s->password, 0, strlen(s->password));
2910 crWaitUntil(ispkt);
2911 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2912 if (flags & FLAG_VERBOSE)
2913 c_write_str(ssh, "Access denied\r\n");
2914 logevent("Authentication refused");
2915 } else if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
2916 bombout((ssh,"Strange packet received, type %d", ssh->pktin.type));
2917 crReturn(0);
2918 }
2919 }
2920
2921 logevent("Authentication successful");
2922
2923 crFinish(1);
2924 }
2925
2926 void sshfwd_close(struct ssh_channel *c)
2927 {
2928 Ssh ssh = c->ssh;
2929
2930 if (c && !c->closes) {
2931 /*
2932 * If the channel's remoteid is -1, we have sent
2933 * CHANNEL_OPEN for this channel, but it hasn't even been
2934 * acknowledged by the server. So we must set a close flag
2935 * on it now, and then when the server acks the channel
2936 * open, we can close it then.
2937 */
2938 if (((int)c->remoteid) != -1) {
2939 if (ssh->version == 1) {
2940 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid,
2941 PKT_END);
2942 } else {
2943 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
2944 ssh2_pkt_adduint32(ssh, c->remoteid);
2945 ssh2_pkt_send(ssh);
2946 }
2947 }
2948 c->closes = 1; /* sent MSG_CLOSE */
2949 if (c->type == CHAN_X11) {
2950 c->u.x11.s = NULL;
2951 logevent("Forwarded X11 connection terminated");
2952 } else if (c->type == CHAN_SOCKDATA ||
2953 c->type == CHAN_SOCKDATA_DORMANT) {
2954 c->u.pfd.s = NULL;
2955 logevent("Forwarded port closed");
2956 }
2957 }
2958 }
2959
2960 int sshfwd_write(struct ssh_channel *c, char *buf, int len)
2961 {
2962 Ssh ssh = c->ssh;
2963
2964 if (ssh->version == 1) {
2965 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
2966 PKT_INT, c->remoteid,
2967 PKT_INT, len, PKT_DATA, buf, len, PKT_END);
2968 /*
2969 * In SSH1 we can return 0 here - implying that forwarded
2970 * connections are never individually throttled - because
2971 * the only circumstance that can cause throttling will be
2972 * the whole SSH connection backing up, in which case
2973 * _everything_ will be throttled as a whole.
2974 */
2975 return 0;
2976 } else {
2977 ssh2_add_channel_data(c, buf, len);
2978 return ssh2_try_send(c);
2979 }
2980 }
2981
2982 void sshfwd_unthrottle(struct ssh_channel *c, int bufsize)
2983 {
2984 Ssh ssh = c->ssh;
2985
2986 if (ssh->version == 1) {
2987 if (c->v.v1.throttling && bufsize < SSH1_BUFFER_LIMIT) {
2988 c->v.v1.throttling = 0;
2989 ssh1_throttle(ssh, -1);
2990 }
2991 } else {
2992 ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
2993 }
2994 }
2995
2996 static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
2997 {
2998 crBegin(ssh->ssh1_protocol_crstate);
2999
3000 random_init();
3001
3002 while (!do_ssh1_login(ssh, in, inlen, ispkt)) {
3003 crReturnV;
3004 }
3005 if (ssh->state == SSH_STATE_CLOSED)
3006 crReturnV;
3007
3008 if (ssh->cfg.agentfwd && agent_exists()) {
3009 logevent("Requesting agent forwarding");
3010 send_packet(ssh, SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END);
3011 do {
3012 crReturnV;
3013 } while (!ispkt);
3014 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3015 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3016 bombout((ssh,"Protocol confusion"));
3017 crReturnV;
3018 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3019 logevent("Agent forwarding refused");
3020 } else {
3021 logevent("Agent forwarding enabled");
3022 ssh->agentfwd_enabled = TRUE;
3023 }
3024 }
3025
3026 if (ssh->cfg.x11_forward) {
3027 char proto[20], data[64];
3028 logevent("Requesting X11 forwarding");
3029 ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
3030 data, sizeof(data), ssh->cfg.x11_auth);
3031 x11_get_real_auth(ssh->x11auth, ssh->cfg.x11_display);
3032 if (ssh->v1_local_protoflags & SSH1_PROTOFLAG_SCREEN_NUMBER) {
3033 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
3034 PKT_STR, proto, PKT_STR, data,
3035 PKT_INT, x11_get_screen_number(ssh->cfg.x11_display),
3036 PKT_END);
3037 } else {
3038 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
3039 PKT_STR, proto, PKT_STR, data, PKT_END);
3040 }
3041 do {
3042 crReturnV;
3043 } while (!ispkt);
3044 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3045 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3046 bombout((ssh,"Protocol confusion"));
3047 crReturnV;
3048 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3049 logevent("X11 forwarding refused");
3050 } else {
3051 logevent("X11 forwarding enabled");
3052 ssh->X11_fwd_enabled = TRUE;
3053 }
3054 }
3055
3056 {
3057 char type;
3058 int n;
3059 int sport,dport,sserv,dserv;
3060 char sports[256], dports[256], saddr[256], host[256];
3061
3062 ssh->rportfwds = newtree234(ssh_rportcmp_ssh1);
3063 /* Add port forwardings. */
3064 ssh->portfwd_strptr = ssh->cfg.portfwd;
3065 while (*ssh->portfwd_strptr) {
3066 type = *ssh->portfwd_strptr++;
3067 saddr[0] = '\0';
3068 n = 0;
3069 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != '\t') {
3070 if (*ssh->portfwd_strptr == ':') {
3071 /*
3072 * We've seen a colon in the middle of the
3073 * source port number. This means that
3074 * everything we've seen until now is the
3075 * source _address_, so we'll move it into
3076 * saddr and start sports from the beginning
3077 * again.
3078 */
3079 ssh->portfwd_strptr++;
3080 sports[n] = '\0';
3081 strcpy(saddr, sports);
3082 n = 0;
3083 }
3084 if (n < 255) sports[n++] = *ssh->portfwd_strptr++;
3085 }
3086 sports[n] = 0;
3087 if (*ssh->portfwd_strptr == '\t')
3088 ssh->portfwd_strptr++;
3089 n = 0;
3090 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':') {
3091 if (n < 255) host[n++] = *ssh->portfwd_strptr++;
3092 }
3093 host[n] = 0;
3094 if (*ssh->portfwd_strptr == ':')
3095 ssh->portfwd_strptr++;
3096 n = 0;
3097 while (*ssh->portfwd_strptr) {
3098 if (n < 255) dports[n++] = *ssh->portfwd_strptr++;
3099 }
3100 dports[n] = 0;
3101 ssh->portfwd_strptr++;
3102 dport = atoi(dports);
3103 dserv = 0;
3104 if (dport == 0) {
3105 dserv = 1;
3106 dport = net_service_lookup(dports);
3107 if (!dport) {
3108 logeventf(ssh, "Service lookup failed for"
3109 " destination port \"%s\"", dports);
3110 }
3111 }
3112 sport = atoi(sports);
3113 sserv = 0;
3114 if (sport == 0) {
3115 sserv = 1;
3116 sport = net_service_lookup(sports);
3117 if (!sport) {
3118 logeventf(ssh, "Service lookup failed for source"
3119 " port \"%s\"", sports);
3120 }
3121 }
3122 if (sport && dport) {
3123 if (type == 'L') {
3124 pfd_addforward(host, dport, *saddr ? saddr : NULL,
3125 sport, ssh, &ssh->cfg);
3126 logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
3127 " forwarding to %s:%.*s%.*s%d%.*s",
3128 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
3129 (int)(*saddr?1:0), ":",
3130 (int)(sserv ? strlen(sports) : 0), sports,
3131 sserv, "(", sport, sserv, ")",
3132 host,
3133 (int)(dserv ? strlen(dports) : 0), dports,
3134 dserv, "(", dport, dserv, ")");
3135 } else {
3136 struct ssh_rportfwd *pf;
3137 pf = smalloc(sizeof(*pf));
3138 strcpy(pf->dhost, host);
3139 pf->dport = dport;
3140 if (saddr) {
3141 logeventf(ssh,
3142 "SSH1 cannot handle source address spec \"%s:%d\"; ignoring",
3143 saddr, sport);
3144 }
3145 if (add234(ssh->rportfwds, pf) != pf) {
3146 logeventf(ssh,
3147 "Duplicate remote port forwarding to %s:%d",
3148 host, dport);
3149 sfree(pf);
3150 } else {
3151 logeventf(ssh, "Requesting remote port %.*s%.*s%d%.*s"
3152 " forward to %s:%.*s%.*s%d%.*s",
3153 (int)(sserv ? strlen(sports) : 0), sports,
3154 sserv, "(", sport, sserv, ")",
3155 host,
3156 (int)(dserv ? strlen(dports) : 0), dports,
3157 dserv, "(", dport, dserv, ")");
3158 send_packet(ssh, SSH1_CMSG_PORT_FORWARD_REQUEST,
3159 PKT_INT, sport,
3160 PKT_STR, host,
3161 PKT_INT, dport,
3162 PKT_END);
3163 do {
3164 crReturnV;
3165 } while (!ispkt);
3166 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3167 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3168 bombout((ssh,"Protocol confusion"));
3169 crReturnV;
3170 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3171 c_write_str(ssh, "Server refused port"
3172 " forwarding\r\n");
3173 }
3174 logevent("Remote port forwarding enabled");
3175 }
3176 }
3177 }
3178 }
3179 }
3180
3181 if (!ssh->cfg.nopty) {
3182 send_packet(ssh, SSH1_CMSG_REQUEST_PTY,
3183 PKT_STR, ssh->cfg.termtype,
3184 PKT_INT, ssh->term_height,
3185 PKT_INT, ssh->term_width,
3186 PKT_INT, 0, PKT_INT, 0, PKT_CHAR, 0, PKT_END);
3187 ssh->state = SSH_STATE_INTERMED;
3188 do {
3189 crReturnV;
3190 } while (!ispkt);
3191 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3192 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3193 bombout((ssh,"Protocol confusion"));
3194 crReturnV;
3195 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3196 c_write_str(ssh, "Server refused to allocate pty\r\n");
3197 ssh->editing = ssh->echoing = 1;
3198 }
3199 logevent("Allocated pty");
3200 } else {
3201 ssh->editing = ssh->echoing = 1;
3202 }
3203
3204 if (ssh->cfg.compression) {
3205 send_packet(ssh, SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END);
3206 do {
3207 crReturnV;
3208 } while (!ispkt);
3209 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3210 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3211 bombout((ssh,"Protocol confusion"));
3212 crReturnV;
3213 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3214 c_write_str(ssh, "Server refused to compress\r\n");
3215 }
3216 logevent("Started compression");
3217 ssh->v1_compressing = TRUE;
3218 ssh->cs_comp_ctx = zlib_compress_init();
3219 logevent("Initialised zlib (RFC1950) compression");
3220 ssh->sc_comp_ctx = zlib_decompress_init();
3221 logevent("Initialised zlib (RFC1950) decompression");
3222 }
3223
3224 /*
3225 * Start the shell or command.
3226 *
3227 * Special case: if the first-choice command is an SSH2
3228 * subsystem (hence not usable here) and the second choice
3229 * exists, we fall straight back to that.
3230 */
3231 {
3232 char *cmd = ssh->cfg.remote_cmd_ptr;
3233
3234 if (ssh->cfg.ssh_subsys && ssh->cfg.remote_cmd_ptr2) {
3235 cmd = ssh->cfg.remote_cmd_ptr2;
3236 ssh->fallback_cmd = TRUE;
3237 }
3238 if (*cmd)
3239 send_packet(ssh, SSH1_CMSG_EXEC_CMD, PKT_STR, cmd, PKT_END);
3240 else
3241 send_packet(ssh, SSH1_CMSG_EXEC_SHELL, PKT_END);
3242 logevent("Started session");
3243 }
3244
3245 ssh->state = SSH_STATE_SESSION;
3246 if (ssh->size_needed)
3247 ssh_size(ssh, ssh->term_width, ssh->term_height);
3248 if (ssh->eof_needed)
3249 ssh_special(ssh, TS_EOF);
3250
3251 if (ssh->ldisc)
3252 ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */
3253 ssh->send_ok = 1;
3254 ssh->channels = newtree234(ssh_channelcmp);
3255 while (1) {
3256 crReturnV;
3257 if (ispkt) {
3258 if (ssh->pktin.type == SSH1_SMSG_STDOUT_DATA ||
3259 ssh->pktin.type == SSH1_SMSG_STDERR_DATA) {
3260 long len = GET_32BIT(ssh->pktin.body);
3261 int bufsize =
3262 from_backend(ssh->frontend,
3263 ssh->pktin.type == SSH1_SMSG_STDERR_DATA,
3264 (char *)(ssh->pktin.body) + 4, len);
3265 if (!ssh->v1_stdout_throttling && bufsize > SSH1_BUFFER_LIMIT) {
3266 ssh->v1_stdout_throttling = 1;
3267 ssh1_throttle(ssh, +1);
3268 }
3269 } else if (ssh->pktin.type == SSH1_MSG_DISCONNECT) {
3270 ssh->state = SSH_STATE_CLOSED;
3271 logevent("Received disconnect request");
3272 crReturnV;
3273 } else if (ssh->pktin.type == SSH1_SMSG_X11_OPEN) {
3274 /* Remote side is trying to open a channel to talk to our
3275 * X-Server. Give them back a local channel number. */
3276 struct ssh_channel *c;
3277
3278 logevent("Received X11 connect request");
3279 /* Refuse if X11 forwarding is disabled. */
3280 if (!ssh->X11_fwd_enabled) {
3281 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3282 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
3283 logevent("Rejected X11 connect request");
3284 } else {
3285 c = smalloc(sizeof(struct ssh_channel));
3286 c->ssh = ssh;
3287
3288 if (x11_init(&c->u.x11.s, ssh->cfg.x11_display, c,
3289 ssh->x11auth, NULL, -1, &ssh->cfg) != NULL) {
3290 logevent("opening X11 forward connection failed");
3291 sfree(c);
3292 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3293 PKT_INT, GET_32BIT(ssh->pktin.body),
3294 PKT_END);
3295 } else {
3296 logevent
3297 ("opening X11 forward connection succeeded");
3298 c->remoteid = GET_32BIT(ssh->pktin.body);
3299 c->localid = alloc_channel_id(ssh);
3300 c->closes = 0;
3301 c->v.v1.throttling = 0;
3302 c->type = CHAN_X11; /* identify channel type */
3303 add234(ssh->channels, c);
3304 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3305 PKT_INT, c->remoteid, PKT_INT,
3306 c->localid, PKT_END);
3307 logevent("Opened X11 forward channel");
3308 }
3309 }
3310 } else if (ssh->pktin.type == SSH1_SMSG_AGENT_OPEN) {
3311 /* Remote side is trying to open a channel to talk to our
3312 * agent. Give them back a local channel number. */
3313 struct ssh_channel *c;
3314
3315 /* Refuse if agent forwarding is disabled. */
3316 if (!ssh->agentfwd_enabled) {
3317 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3318 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
3319 } else {
3320 c = smalloc(sizeof(struct ssh_channel));
3321 c->ssh = ssh;
3322 c->remoteid = GET_32BIT(ssh->pktin.body);
3323 c->localid = alloc_channel_id(ssh);
3324 c->closes = 0;
3325 c->v.v1.throttling = 0;
3326 c->type = CHAN_AGENT; /* identify channel type */
3327 c->u.a.lensofar = 0;
3328 add234(ssh->channels, c);
3329 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3330 PKT_INT, c->remoteid, PKT_INT, c->localid,
3331 PKT_END);
3332 }
3333 } else if (ssh->pktin.type == SSH1_MSG_PORT_OPEN) {
3334 /* Remote side is trying to open a channel to talk to a
3335 * forwarded port. Give them back a local channel number. */
3336 struct ssh_channel *c;
3337 struct ssh_rportfwd pf;
3338 int hostsize, port;
3339 char host[256], buf[1024];
3340 char *p, *h, *e;
3341 c = smalloc(sizeof(struct ssh_channel));
3342 c->ssh = ssh;
3343
3344 hostsize = GET_32BIT(ssh->pktin.body+4);
3345 for (h = host, p = (char *)(ssh->pktin.body+8);
3346 hostsize != 0; hostsize--) {
3347 if (h+1 < host+sizeof(host))
3348 *h++ = *p;
3349 p++;
3350 }
3351 *h = 0;
3352 port = GET_32BIT(p);
3353
3354 strcpy(pf.dhost, host);
3355 pf.dport = port;
3356
3357 if (find234(ssh->rportfwds, &pf, NULL) == NULL) {
3358 sprintf(buf, "Rejected remote port open request for %s:%d",
3359 host, port);
3360 logevent(buf);
3361 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3362 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
3363 } else {
3364 sprintf(buf, "Received remote port open request for %s:%d",
3365 host, port);
3366 logevent(buf);
3367 e = pfd_newconnect(&c->u.pfd.s, host, port, c, &ssh->cfg);
3368 if (e != NULL) {
3369 char buf[256];
3370 sprintf(buf, "Port open failed: %s", e);
3371 logevent(buf);
3372 sfree(c);
3373 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3374 PKT_INT, GET_32BIT(ssh->pktin.body),
3375 PKT_END);
3376 } else {
3377 c->remoteid = GET_32BIT(ssh->pktin.body);
3378 c->localid = alloc_channel_id(ssh);
3379 c->closes = 0;
3380 c->v.v1.throttling = 0;
3381 c->type = CHAN_SOCKDATA; /* identify channel type */
3382 add234(ssh->channels, c);
3383 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3384 PKT_INT, c->remoteid, PKT_INT,
3385 c->localid, PKT_END);
3386 logevent("Forwarded port opened successfully");
3387 }
3388 }
3389
3390 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_OPEN_CONFIRMATION) {
3391 unsigned int remoteid = GET_32BIT(ssh->pktin.body);
3392 unsigned int localid = GET_32BIT(ssh->pktin.body+4);
3393 struct ssh_channel *c;
3394
3395 c = find234(ssh->channels, &remoteid, ssh_channelfind);
3396 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
3397 c->remoteid = localid;
3398 c->type = CHAN_SOCKDATA;
3399 c->v.v1.throttling = 0;
3400 pfd_confirm(c->u.pfd.s);
3401 }
3402
3403 if (c && c->closes) {
3404 /*
3405 * We have a pending close on this channel,
3406 * which we decided on before the server acked
3407 * the channel open. So now we know the
3408 * remoteid, we can close it again.
3409 */
3410 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE,
3411 PKT_INT, c->remoteid, PKT_END);
3412 }
3413
3414 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_OPEN_FAILURE) {
3415 unsigned int remoteid = GET_32BIT(ssh->pktin.body);
3416 struct ssh_channel *c;
3417
3418 c = find234(ssh->channels, &remoteid, ssh_channelfind);
3419 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
3420 logevent("Forwarded connection refused by server");
3421 pfd_close(c->u.pfd.s);
3422 del234(ssh->channels, c);
3423 sfree(c);
3424 }
3425
3426 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ||
3427 ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION) {
3428 /* Remote side closes a channel. */
3429 unsigned i = GET_32BIT(ssh->pktin.body);
3430 struct ssh_channel *c;
3431 c = find234(ssh->channels, &i, ssh_channelfind);
3432 if (c && ((int)c->remoteid) != -1) {
3433 int closetype;
3434 closetype =
3435 (ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ? 1 : 2);
3436
3437 if ((c->closes == 0) && (c->type == CHAN_X11)) {
3438 logevent("Forwarded X11 connection terminated");
3439 assert(c->u.x11.s != NULL);
3440 x11_close(c->u.x11.s);
3441 c->u.x11.s = NULL;
3442 }
3443 if ((c->closes == 0) && (c->type == CHAN_SOCKDATA)) {
3444 logevent("Forwarded port closed");
3445 assert(c->u.pfd.s != NULL);
3446 pfd_close(c->u.pfd.s);
3447 c->u.pfd.s = NULL;
3448 }
3449
3450 c->closes |= (closetype << 2); /* seen this message */
3451 if (!(c->closes & closetype)) {
3452 send_packet(ssh, ssh->pktin.type, PKT_INT, c->remoteid,
3453 PKT_END);
3454 c->closes |= closetype; /* sent it too */
3455 }
3456
3457 if (c->closes == 15) {
3458 del234(ssh->channels, c);
3459 sfree(c);
3460 }
3461 } else {
3462 bombout((ssh,"Received CHANNEL_CLOSE%s for %s channel %d\n",
3463 ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ? "" :
3464 "_CONFIRMATION", c ? "half-open" : "nonexistent",
3465 i));
3466 }
3467 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_DATA) {
3468 /* Data sent down one of our channels. */
3469 int i = GET_32BIT(ssh->pktin.body);
3470 int len = GET_32BIT(ssh->pktin.body + 4);
3471 unsigned char *p = ssh->pktin.body + 8;
3472 struct ssh_channel *c;
3473 c = find234(ssh->channels, &i, ssh_channelfind);
3474 if (c) {
3475 int bufsize;
3476 switch (c->type) {
3477 case CHAN_X11:
3478 bufsize = x11_send(c->u.x11.s, (char *)p, len);
3479 break;
3480 case CHAN_SOCKDATA:
3481 bufsize = pfd_send(c->u.pfd.s, (char *)p, len);
3482 break;
3483 case CHAN_AGENT:
3484 /* Data for an agent message. Buffer it. */
3485 while (len > 0) {
3486 if (c->u.a.lensofar < 4) {
3487 int l = min(4 - c->u.a.lensofar, len);
3488 memcpy(c->u.a.msglen + c->u.a.lensofar, p,
3489 l);
3490 p += l;
3491 len -= l;
3492 c->u.a.lensofar += l;
3493 }
3494 if (c->u.a.lensofar == 4) {
3495 c->u.a.totallen =
3496 4 + GET_32BIT(c->u.a.msglen);
3497 c->u.a.message = smalloc(c->u.a.totallen);
3498 memcpy(c->u.a.message, c->u.a.msglen, 4);
3499 }
3500 if (c->u.a.lensofar >= 4 && len > 0) {
3501 int l =
3502 min(c->u.a.totallen - c->u.a.lensofar,
3503 len);
3504 memcpy(c->u.a.message + c->u.a.lensofar, p,
3505 l);
3506 p += l;
3507 len -= l;
3508 c->u.a.lensofar += l;
3509 }
3510 if (c->u.a.lensofar == c->u.a.totallen) {
3511 void *reply, *sentreply;
3512 int replylen;
3513 agent_query(c->u.a.message,
3514 c->u.a.totallen, &reply,
3515 &replylen);
3516 if (reply)
3517 sentreply = reply;
3518 else {
3519 /* Fake SSH_AGENT_FAILURE. */
3520 sentreply = "\0\0\0\1\5";
3521 replylen = 5;
3522 }
3523 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
3524 PKT_INT, c->remoteid,
3525 PKT_INT, replylen,
3526 PKT_DATA, sentreply, replylen,
3527 PKT_END);
3528 if (reply)
3529 sfree(reply);
3530 sfree(c->u.a.message);
3531 c->u.a.lensofar = 0;
3532 }
3533 }
3534 bufsize = 0; /* agent channels never back up */
3535 break;
3536 }
3537 if (!c->v.v1.throttling && bufsize > SSH1_BUFFER_LIMIT) {
3538 c->v.v1.throttling = 1;
3539 ssh1_throttle(ssh, +1);
3540 }
3541 }
3542 } else if (ssh->pktin.type == SSH1_SMSG_SUCCESS) {
3543 /* may be from EXEC_SHELL on some servers */
3544 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3545 /* may be from EXEC_SHELL on some servers
3546 * if no pty is available or in other odd cases. Ignore */
3547 } else if (ssh->pktin.type == SSH1_SMSG_EXIT_STATUS) {
3548 char buf[100];
3549 ssh->exitcode = GET_32BIT(ssh->pktin.body);
3550 sprintf(buf, "Server sent command exit status %d",
3551 ssh->exitcode);
3552 logevent(buf);
3553 send_packet(ssh, SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
3554 /*
3555 * In case `helpful' firewalls or proxies tack
3556 * extra human-readable text on the end of the
3557 * session which we might mistake for another
3558 * encrypted packet, we close the session once
3559 * we've sent EXIT_CONFIRMATION.
3560 */
3561 ssh->state = SSH_STATE_CLOSED;
3562 crReturnV;
3563 } else {
3564 bombout((ssh,"Strange packet received: type %d", ssh->pktin.type));
3565 crReturnV;
3566 }
3567 } else {
3568 while (inlen > 0) {
3569 int len = min(inlen, 512);
3570 send_packet(ssh, SSH1_CMSG_STDIN_DATA,
3571 PKT_INT, len, PKT_DATA, in, len, PKT_END);
3572 in += len;
3573 inlen -= len;
3574 }
3575 }
3576 }
3577
3578 crFinishV;
3579 }
3580
3581 /*
3582 * Utility routine for decoding comma-separated strings in KEXINIT.
3583 */
3584 static int in_commasep_string(char *needle, char *haystack, int haylen)
3585 {
3586 int needlen;
3587 if (!needle || !haystack) /* protect against null pointers */
3588 return 0;
3589 needlen = strlen(needle);
3590 while (1) {
3591 /*
3592 * Is it at the start of the string?
3593 */
3594 if (haylen >= needlen && /* haystack is long enough */
3595 !memcmp(needle, haystack, needlen) && /* initial match */
3596 (haylen == needlen || haystack[needlen] == ',')
3597 /* either , or EOS follows */
3598 )
3599 return 1;
3600 /*
3601 * If not, search for the next comma and resume after that.
3602 * If no comma found, terminate.
3603 */
3604 while (haylen > 0 && *haystack != ',')
3605 haylen--, haystack++;
3606 if (haylen == 0)
3607 return 0;
3608 haylen--, haystack++; /* skip over comma itself */
3609 }
3610 }
3611
3612 /*
3613 * SSH2 key creation method.
3614 */
3615 static void ssh2_mkkey(Ssh ssh, Bignum K, unsigned char *H,
3616 unsigned char *sessid, char chr,
3617 unsigned char *keyspace)
3618 {
3619 SHA_State s;
3620 /* First 20 bytes. */
3621 SHA_Init(&s);
3622 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
3623 sha_mpint(&s, K);
3624 SHA_Bytes(&s, H, 20);
3625 SHA_Bytes(&s, &chr, 1);
3626 SHA_Bytes(&s, sessid, 20);
3627 SHA_Final(&s, keyspace);
3628 /* Next 20 bytes. */
3629 SHA_Init(&s);
3630 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
3631 sha_mpint(&s, K);
3632 SHA_Bytes(&s, H, 20);
3633 SHA_Bytes(&s, keyspace, 20);
3634 SHA_Final(&s, keyspace + 20);
3635 }
3636
3637 /*
3638 * Handle the SSH2 transport layer.
3639 */
3640 static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
3641 {
3642 struct do_ssh2_transport_state {
3643 int nbits, pbits, warn;
3644 Bignum p, g, e, f, K;
3645 int kex_init_value, kex_reply_value;
3646 const struct ssh_mac **maclist;
3647 int nmacs;
3648 const struct ssh2_cipher *cscipher_tobe;
3649 const struct ssh2_cipher *sccipher_tobe;
3650 const struct ssh_mac *csmac_tobe;
3651 const struct ssh_mac *scmac_tobe;
3652 const struct ssh_compress *cscomp_tobe;
3653 const struct ssh_compress *sccomp_tobe;
3654 char *hostkeydata, *sigdata, *keystr, *fingerprint;
3655 int hostkeylen, siglen;
3656 void *hkey; /* actual host key */
3657 unsigned char exchange_hash[20];
3658 int n_preferred_ciphers;
3659 const struct ssh2_ciphers *preferred_ciphers[CIPHER_MAX];
3660 const struct ssh_compress *preferred_comp;
3661 int first_kex;
3662 };
3663 crState(do_ssh2_transport_state);
3664
3665 crBegin(ssh->do_ssh2_transport_crstate);
3666
3667 s->cscipher_tobe = s->sccipher_tobe = NULL;
3668 s->csmac_tobe = s->scmac_tobe = NULL;
3669 s->cscomp_tobe = s->sccomp_tobe = NULL;
3670
3671 random_init();
3672 s->first_kex = 1;
3673
3674 {
3675 int i;
3676 /*
3677 * Set up the preferred ciphers. (NULL => warn below here)
3678 */
3679 s->n_preferred_ciphers = 0;
3680 for (i = 0; i < CIPHER_MAX; i++) {
3681 switch (ssh->cfg.ssh_cipherlist[i]) {
3682 case CIPHER_BLOWFISH:
3683 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_blowfish;
3684 break;
3685 case CIPHER_DES:
3686 if (ssh->cfg.ssh2_des_cbc) {
3687 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_des;
3688 }
3689 break;
3690 case CIPHER_3DES:
3691 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_3des;
3692 break;
3693 case CIPHER_AES:
3694 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_aes;
3695 break;
3696 case CIPHER_WARN:
3697 /* Flag for later. Don't bother if it's the last in
3698 * the list. */
3699 if (i < CIPHER_MAX - 1) {
3700 s->preferred_ciphers[s->n_preferred_ciphers++] = NULL;
3701 }
3702 break;
3703 }
3704 }
3705 }
3706
3707 /*
3708 * Set up preferred compression.
3709 */
3710 if (ssh->cfg.compression)
3711 s->preferred_comp = &ssh_zlib;
3712 else
3713 s->preferred_comp = &ssh_comp_none;
3714
3715 /*
3716 * Be prepared to work around the buggy MAC problem.
3717 */
3718 if (ssh->remote_bugs & BUG_SSH2_HMAC)
3719 s->maclist = buggymacs, s->nmacs = lenof(buggymacs);
3720 else
3721 s->maclist = macs, s->nmacs = lenof(macs);
3722
3723 begin_key_exchange:
3724 {
3725 int i, j, cipherstr_started;
3726
3727 /*
3728 * Construct and send our key exchange packet.
3729 */
3730 ssh2_pkt_init(ssh, SSH2_MSG_KEXINIT);
3731 for (i = 0; i < 16; i++)
3732 ssh2_pkt_addbyte(ssh, (unsigned char) random_byte());
3733 /* List key exchange algorithms. */
3734 ssh2_pkt_addstring_start(ssh);
3735 for (i = 0; i < lenof(kex_algs); i++) {
3736 if (kex_algs[i] == &ssh_diffiehellman_gex &&
3737 (ssh->remote_bugs & BUG_SSH2_DH_GEX))
3738 continue;
3739 ssh2_pkt_addstring_str(ssh, kex_algs[i]->name);
3740 if (i < lenof(kex_algs) - 1)
3741 ssh2_pkt_addstring_str(ssh, ",");
3742 }
3743 /* List server host key algorithms. */
3744 ssh2_pkt_addstring_start(ssh);
3745 for (i = 0; i < lenof(hostkey_algs); i++) {
3746 ssh2_pkt_addstring_str(ssh, hostkey_algs[i]->name);
3747 if (i < lenof(hostkey_algs) - 1)
3748 ssh2_pkt_addstring_str(ssh, ",");
3749 }
3750 /* List client->server encryption algorithms. */
3751 ssh2_pkt_addstring_start(ssh);
3752 cipherstr_started = 0;
3753 for (i = 0; i < s->n_preferred_ciphers; i++) {
3754 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3755 if (!c) continue; /* warning flag */
3756 for (j = 0; j < c->nciphers; j++) {
3757 if (cipherstr_started)
3758 ssh2_pkt_addstring_str(ssh, ",");
3759 ssh2_pkt_addstring_str(ssh, c->list[j]->name);
3760 cipherstr_started = 1;
3761 }
3762 }
3763 /* List server->client encryption algorithms. */
3764 ssh2_pkt_addstring_start(ssh);
3765 cipherstr_started = 0;
3766 for (i = 0; i < s->n_preferred_ciphers; i++) {
3767 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3768 if (!c) continue; /* warning flag */
3769 for (j = 0; j < c->nciphers; j++) {
3770 if (cipherstr_started)
3771 ssh2_pkt_addstring_str(ssh, ",");
3772 ssh2_pkt_addstring_str(ssh, c->list[j]->name);
3773 cipherstr_started = 1;
3774 }
3775 }
3776 /* List client->server MAC algorithms. */
3777 ssh2_pkt_addstring_start(ssh);
3778 for (i = 0; i < s->nmacs; i++) {
3779 ssh2_pkt_addstring_str(ssh, s->maclist[i]->name);
3780 if (i < s->nmacs - 1)
3781 ssh2_pkt_addstring_str(ssh, ",");
3782 }
3783 /* List server->client MAC algorithms. */
3784 ssh2_pkt_addstring_start(ssh);
3785 for (i = 0; i < s->nmacs; i++) {
3786 ssh2_pkt_addstring_str(ssh, s->maclist[i]->name);
3787 if (i < s->nmacs - 1)
3788 ssh2_pkt_addstring_str(ssh, ",");
3789 }
3790 /* List client->server compression algorithms. */
3791 ssh2_pkt_addstring_start(ssh);
3792 for (i = 0; i < lenof(compressions) + 1; i++) {
3793 const struct ssh_compress *c =
3794 i == 0 ? s->preferred_comp : compressions[i - 1];
3795 ssh2_pkt_addstring_str(ssh, c->name);
3796 if (i < lenof(compressions))
3797 ssh2_pkt_addstring_str(ssh, ",");
3798 }
3799 /* List server->client compression algorithms. */
3800 ssh2_pkt_addstring_start(ssh);
3801 for (i = 0; i < lenof(compressions) + 1; i++) {
3802 const struct ssh_compress *c =
3803 i == 0 ? s->preferred_comp : compressions[i - 1];
3804 ssh2_pkt_addstring_str(ssh, c->name);
3805 if (i < lenof(compressions))
3806 ssh2_pkt_addstring_str(ssh, ",");
3807 }
3808 /* List client->server languages. Empty list. */
3809 ssh2_pkt_addstring_start(ssh);
3810 /* List server->client languages. Empty list. */
3811 ssh2_pkt_addstring_start(ssh);
3812 /* First KEX packet does _not_ follow, because we're not that brave. */
3813 ssh2_pkt_addbool(ssh, FALSE);
3814 /* Reserved. */
3815 ssh2_pkt_adduint32(ssh, 0);
3816 }
3817
3818 ssh->exhash = ssh->exhashbase;
3819 sha_string(&ssh->exhash, ssh->pktout.data + 5, ssh->pktout.length - 5);
3820
3821 ssh2_pkt_send(ssh);
3822
3823 if (!ispkt)
3824 crWaitUntil(ispkt);
3825 if (ssh->pktin.length > 5)
3826 sha_string(&ssh->exhash, ssh->pktin.data + 5, ssh->pktin.length - 5);
3827
3828 /*
3829 * Now examine the other side's KEXINIT to see what we're up
3830 * to.
3831 */
3832 {
3833 char *str;
3834 int i, j, len;
3835
3836 if (ssh->pktin.type != SSH2_MSG_KEXINIT) {
3837 bombout((ssh,"expected key exchange packet from server"));
3838 crReturn(0);
3839 }
3840 ssh->kex = NULL;
3841 ssh->hostkey = NULL;
3842 s->cscipher_tobe = NULL;
3843 s->sccipher_tobe = NULL;
3844 s->csmac_tobe = NULL;
3845 s->scmac_tobe = NULL;
3846 s->cscomp_tobe = NULL;
3847 s->sccomp_tobe = NULL;
3848 ssh->pktin.savedpos += 16; /* skip garbage cookie */
3849 ssh2_pkt_getstring(ssh, &str, &len); /* key exchange algorithms */
3850 for (i = 0; i < lenof(kex_algs); i++) {
3851 if (kex_algs[i] == &ssh_diffiehellman_gex &&
3852 (ssh->remote_bugs & BUG_SSH2_DH_GEX))
3853 continue;
3854 if (in_commasep_string(kex_algs[i]->name, str, len)) {
3855 ssh->kex = kex_algs[i];
3856 break;
3857 }
3858 }
3859 ssh2_pkt_getstring(ssh, &str, &len); /* host key algorithms */
3860 for (i = 0; i < lenof(hostkey_algs); i++) {
3861 if (in_commasep_string(hostkey_algs[i]->name, str, len)) {
3862 ssh->hostkey = hostkey_algs[i];
3863 break;
3864 }
3865 }
3866 ssh2_pkt_getstring(ssh, &str, &len); /* client->server cipher */
3867 s->warn = 0;
3868 for (i = 0; i < s->n_preferred_ciphers; i++) {
3869 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3870 if (!c) {
3871 s->warn = 1;
3872 } else {
3873 for (j = 0; j < c->nciphers; j++) {
3874 if (in_commasep_string(c->list[j]->name, str, len)) {
3875 s->cscipher_tobe = c->list[j];
3876 break;
3877 }
3878 }
3879 }
3880 if (s->cscipher_tobe) {
3881 if (s->warn)
3882 askcipher(ssh->frontend, s->cscipher_tobe->name, 1);
3883 break;
3884 }
3885 }
3886 if (!s->cscipher_tobe) {
3887 bombout((ssh,"Couldn't agree a client-to-server cipher (available: %s)",
3888 str ? str : "(null)"));
3889 crReturn(0);
3890 }
3891
3892 ssh2_pkt_getstring(ssh, &str, &len); /* server->client cipher */
3893 s->warn = 0;
3894 for (i = 0; i < s->n_preferred_ciphers; i++) {
3895 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3896 if (!c) {
3897 s->warn = 1;
3898 } else {
3899 for (j = 0; j < c->nciphers; j++) {
3900 if (in_commasep_string(c->list[j]->name, str, len)) {
3901 s->sccipher_tobe = c->list[j];
3902 break;
3903 }
3904 }
3905 }
3906 if (s->sccipher_tobe) {
3907 if (s->warn)
3908 askcipher(ssh->frontend, s->sccipher_tobe->name, 2);
3909 break;
3910 }
3911 }
3912 if (!s->sccipher_tobe) {
3913 bombout((ssh,"Couldn't agree a server-to-client cipher (available: %s)",
3914 str ? str : "(null)"));
3915 crReturn(0);
3916 }
3917
3918 ssh2_pkt_getstring(ssh, &str, &len); /* client->server mac */
3919 for (i = 0; i < s->nmacs; i++) {
3920 if (in_commasep_string(s->maclist[i]->name, str, len)) {
3921 s->csmac_tobe = s->maclist[i];
3922 break;
3923 }
3924 }
3925 ssh2_pkt_getstring(ssh, &str, &len); /* server->client mac */
3926 for (i = 0; i < s->nmacs; i++) {
3927 if (in_commasep_string(s->maclist[i]->name, str, len)) {
3928 s->scmac_tobe = s->maclist[i];
3929 break;
3930 }
3931 }
3932 ssh2_pkt_getstring(ssh, &str, &len); /* client->server compression */
3933 for (i = 0; i < lenof(compressions) + 1; i++) {
3934 const struct ssh_compress *c =
3935 i == 0 ? s->preferred_comp : compressions[i - 1];
3936 if (in_commasep_string(c->name, str, len)) {
3937 s->cscomp_tobe = c;
3938 break;
3939 }
3940 }
3941 ssh2_pkt_getstring(ssh, &str, &len); /* server->client compression */
3942 for (i = 0; i < lenof(compressions) + 1; i++) {
3943 const struct ssh_compress *c =
3944 i == 0 ? s->preferred_comp : compressions[i - 1];
3945 if (in_commasep_string(c->name, str, len)) {
3946 s->sccomp_tobe = c;
3947 break;
3948 }
3949 }
3950 }
3951
3952 /*
3953 * Work out the number of bits of key we will need from the key
3954 * exchange. We start with the maximum key length of either
3955 * cipher...
3956 */
3957 {
3958 int csbits, scbits;
3959
3960 csbits = s->cscipher_tobe->keylen;
3961 scbits = s->sccipher_tobe->keylen;
3962 s->nbits = (csbits > scbits ? csbits : scbits);
3963 }
3964 /* The keys only have 160-bit entropy, since they're based on
3965 * a SHA-1 hash. So cap the key size at 160 bits. */
3966 if (s->nbits > 160)
3967 s->nbits = 160;
3968
3969 /*
3970 * If we're doing Diffie-Hellman group exchange, start by
3971 * requesting a group.
3972 */
3973 if (ssh->kex == &ssh_diffiehellman_gex) {
3974 logevent("Doing Diffie-Hellman group exchange");
3975 ssh->pkt_ctx |= SSH2_PKTCTX_DHGEX;
3976 /*
3977 * Work out how big a DH group we will need to allow that
3978 * much data.
3979 */
3980 s->pbits = 512 << ((s->nbits - 1) / 64);
3981 ssh2_pkt_init(ssh, SSH2_MSG_KEX_DH_GEX_REQUEST);
3982 ssh2_pkt_adduint32(ssh, s->pbits);
3983 ssh2_pkt_send(ssh);
3984
3985 crWaitUntil(ispkt);
3986 if (ssh->pktin.type != SSH2_MSG_KEX_DH_GEX_GROUP) {
3987 bombout((ssh,"expected key exchange group packet from server"));
3988 crReturn(0);
3989 }
3990 s->p = ssh2_pkt_getmp(ssh);
3991 s->g = ssh2_pkt_getmp(ssh);
3992 ssh->kex_ctx = dh_setup_group(s->p, s->g);
3993 s->kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT;
3994 s->kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY;
3995 } else {
3996 ssh->pkt_ctx |= SSH2_PKTCTX_DHGROUP1;
3997 ssh->kex_ctx = dh_setup_group1();
3998 s->kex_init_value = SSH2_MSG_KEXDH_INIT;
3999 s->kex_reply_value = SSH2_MSG_KEXDH_REPLY;
4000 }
4001
4002 logevent("Doing Diffie-Hellman key exchange");
4003 /*
4004 * Now generate and send e for Diffie-Hellman.
4005 */
4006 s->e = dh_create_e(ssh->kex_ctx, s->nbits * 2);
4007 ssh2_pkt_init(ssh, s->kex_init_value);
4008 ssh2_pkt_addmp(ssh, s->e);
4009 ssh2_pkt_send(ssh);
4010
4011 crWaitUntil(ispkt);
4012 if (ssh->pktin.type != s->kex_reply_value) {
4013 bombout((ssh,"expected key exchange reply packet from server"));
4014 crReturn(0);
4015 }
4016 ssh2_pkt_getstring(ssh, &s->hostkeydata, &s->hostkeylen);
4017 s->f = ssh2_pkt_getmp(ssh);
4018 ssh2_pkt_getstring(ssh, &s->sigdata, &s->siglen);
4019
4020 s->K = dh_find_K(ssh->kex_ctx, s->f);
4021
4022 sha_string(&ssh->exhash, s->hostkeydata, s->hostkeylen);
4023 if (ssh->kex == &ssh_diffiehellman_gex) {
4024 sha_uint32(&ssh->exhash, s->pbits);
4025 sha_mpint(&ssh->exhash, s->p);
4026 sha_mpint(&ssh->exhash, s->g);
4027 }
4028 sha_mpint(&ssh->exhash, s->e);
4029 sha_mpint(&ssh->exhash, s->f);
4030 sha_mpint(&ssh->exhash, s->K);
4031 SHA_Final(&ssh->exhash, s->exchange_hash);
4032
4033 dh_cleanup(ssh->kex_ctx);
4034
4035 #if 0
4036 debug(("Exchange hash is:\n"));
4037 dmemdump(s->exchange_hash, 20);
4038 #endif
4039
4040 s->hkey = ssh->hostkey->newkey(s->hostkeydata, s->hostkeylen);
4041 if (!s->hkey ||
4042 !ssh->hostkey->verifysig(s->hkey, s->sigdata, s->siglen,
4043 (char *)s->exchange_hash, 20)) {
4044 bombout((ssh,"Server's host key did not match the signature supplied"));
4045 crReturn(0);
4046 }
4047
4048 /*
4049 * Authenticate remote host: verify host key. (We've already
4050 * checked the signature of the exchange hash.)
4051 */
4052 s->keystr = ssh->hostkey->fmtkey(s->hkey);
4053 s->fingerprint = ssh->hostkey->fingerprint(s->hkey);
4054 verify_ssh_host_key(ssh->frontend,
4055 ssh->savedhost, ssh->savedport, ssh->hostkey->keytype,
4056 s->keystr, s->fingerprint);
4057 if (s->first_kex) { /* don't bother logging this in rekeys */
4058 logevent("Host key fingerprint is:");
4059 logevent(s->fingerprint);
4060 }
4061 sfree(s->fingerprint);
4062 sfree(s->keystr);
4063 ssh->hostkey->freekey(s->hkey);
4064
4065 /*
4066 * Send SSH2_MSG_NEWKEYS.
4067 */
4068 ssh2_pkt_init(ssh, SSH2_MSG_NEWKEYS);
4069 ssh2_pkt_send(ssh);
4070
4071 /*
4072 * Expect SSH2_MSG_NEWKEYS from server.
4073 */
4074 crWaitUntil(ispkt);
4075 if (ssh->pktin.type != SSH2_MSG_NEWKEYS) {
4076 bombout((ssh,"expected new-keys packet from server"));
4077 crReturn(0);
4078 }
4079
4080 /*
4081 * Create and initialise session keys.
4082 */
4083 if (ssh->cs_cipher_ctx)
4084 ssh->cscipher->free_context(ssh->cs_cipher_ctx);
4085 ssh->cscipher = s->cscipher_tobe;
4086 ssh->cs_cipher_ctx = ssh->cscipher->make_context();
4087
4088 if (ssh->sc_cipher_ctx)
4089 ssh->sccipher->free_context(ssh->sc_cipher_ctx);
4090 ssh->sccipher = s->sccipher_tobe;
4091 ssh->sc_cipher_ctx = ssh->sccipher->make_context();
4092
4093 if (ssh->cs_mac_ctx)
4094 ssh->csmac->free_context(ssh->cs_mac_ctx);
4095 ssh->csmac = s->csmac_tobe;
4096 ssh->cs_mac_ctx = ssh->csmac->make_context();
4097
4098 if (ssh->sc_mac_ctx)
4099 ssh->scmac->free_context(ssh->sc_mac_ctx);
4100 ssh->scmac = s->scmac_tobe;
4101 ssh->sc_mac_ctx = ssh->scmac->make_context();
4102
4103 if (ssh->cs_comp_ctx)
4104 ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
4105 ssh->cscomp = s->cscomp_tobe;
4106 ssh->cs_comp_ctx = ssh->cscomp->compress_init();
4107
4108 if (ssh->sc_comp_ctx)
4109 ssh->sccomp->decompress_cleanup(ssh->sc_comp_ctx);
4110 ssh->sccomp = s->sccomp_tobe;
4111 ssh->sc_comp_ctx = ssh->sccomp->decompress_init();
4112
4113 /*
4114 * Set IVs after keys. Here we use the exchange hash from the
4115 * _first_ key exchange.
4116 */
4117 {
4118 unsigned char keyspace[40];
4119 if (s->first_kex)
4120 memcpy(ssh->v2_session_id, s->exchange_hash,
4121 sizeof(s->exchange_hash));
4122 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'C',keyspace);
4123 ssh->cscipher->setkey(ssh->cs_cipher_ctx, keyspace);
4124 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'D',keyspace);
4125 ssh->sccipher->setkey(ssh->sc_cipher_ctx, keyspace);
4126 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'A',keyspace);
4127 ssh->cscipher->setiv(ssh->cs_cipher_ctx, keyspace);
4128 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'B',keyspace);
4129 ssh->sccipher->setiv(ssh->sc_cipher_ctx, keyspace);
4130 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'E',keyspace);
4131 ssh->csmac->setkey(ssh->cs_mac_ctx, keyspace);
4132 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'F',keyspace);
4133 ssh->scmac->setkey(ssh->sc_mac_ctx, keyspace);
4134 }
4135 logeventf(ssh, "Initialised %.200s client->server encryption",
4136 ssh->cscipher->text_name);
4137 logeventf(ssh, "Initialised %.200s server->client encryption",
4138 ssh->sccipher->text_name);
4139 if (ssh->cscomp->text_name)
4140 logeventf(ssh, "Initialised %s compression",
4141 ssh->cscomp->text_name);
4142 if (ssh->sccomp->text_name)
4143 logeventf(ssh, "Initialised %s decompression",
4144 ssh->sccomp->text_name);
4145
4146 /*
4147 * If this is the first key exchange phase, we must pass the
4148 * SSH2_MSG_NEWKEYS packet to the next layer, not because it
4149 * wants to see it but because it will need time to initialise
4150 * itself before it sees an actual packet. In subsequent key
4151 * exchange phases, we don't pass SSH2_MSG_NEWKEYS on, because
4152 * it would only confuse the layer above.
4153 */
4154 if (!s->first_kex) {
4155 crReturn(0);
4156 }
4157 s->first_kex = 0;
4158
4159 /*
4160 * Now we're encrypting. Begin returning 1 to the protocol main
4161 * function so that other things can run on top of the
4162 * transport. If we ever see a KEXINIT, we must go back to the
4163 * start.
4164 */
4165 while (!(ispkt && ssh->pktin.type == SSH2_MSG_KEXINIT)) {
4166 crReturn(1);
4167 }
4168 logevent("Server initiated key re-exchange");
4169 goto begin_key_exchange;
4170
4171 crFinish(1);
4172 }
4173
4174 /*
4175 * Add data to an SSH2 channel output buffer.
4176 */
4177 static void ssh2_add_channel_data(struct ssh_channel *c, char *buf,
4178 int len)
4179 {
4180 bufchain_add(&c->v.v2.outbuffer, buf, len);
4181 }
4182
4183 /*
4184 * Attempt to send data on an SSH2 channel.
4185 */
4186 static int ssh2_try_send(struct ssh_channel *c)
4187 {
4188 Ssh ssh = c->ssh;
4189
4190 while (c->v.v2.remwindow > 0 && bufchain_size(&c->v.v2.outbuffer) > 0) {
4191 int len;
4192 void *data;
4193 bufchain_prefix(&c->v.v2.outbuffer, &data, &len);
4194 if ((unsigned)len > c->v.v2.remwindow)
4195 len = c->v.v2.remwindow;
4196 if ((unsigned)len > c->v.v2.remmaxpkt)
4197 len = c->v.v2.remmaxpkt;
4198 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_DATA);
4199 ssh2_pkt_adduint32(ssh, c->remoteid);
4200 ssh2_pkt_addstring_start(ssh);
4201 ssh2_pkt_addstring_data(ssh, data, len);
4202 ssh2_pkt_send(ssh);
4203 bufchain_consume(&c->v.v2.outbuffer, len);
4204 c->v.v2.remwindow -= len;
4205 }
4206
4207 /*
4208 * After having sent as much data as we can, return the amount
4209 * still buffered.
4210 */
4211 return bufchain_size(&c->v.v2.outbuffer);
4212 }
4213
4214 /*
4215 * Potentially enlarge the window on an SSH2 channel.
4216 */
4217 static void ssh2_set_window(struct ssh_channel *c, unsigned newwin)
4218 {
4219 Ssh ssh = c->ssh;
4220
4221 /*
4222 * Never send WINDOW_ADJUST for a channel that the remote side
4223 * already thinks it's closed; there's no point, since it won't
4224 * be sending any more data anyway.
4225 */
4226 if (c->closes != 0)
4227 return;
4228
4229 if (newwin > c->v.v2.locwindow) {
4230 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST);
4231 ssh2_pkt_adduint32(ssh, c->remoteid);
4232 ssh2_pkt_adduint32(ssh, newwin - c->v.v2.locwindow);
4233 ssh2_pkt_send(ssh);
4234 c->v.v2.locwindow = newwin;
4235 }
4236 }
4237
4238 /*
4239 * Handle the SSH2 userauth and connection layers.
4240 */
4241 static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
4242 {
4243 struct do_ssh2_authconn_state {
4244 enum {
4245 AUTH_INVALID, AUTH_PUBLICKEY_AGENT, AUTH_PUBLICKEY_FILE,
4246 AUTH_PASSWORD,
4247 AUTH_KEYBOARD_INTERACTIVE
4248 } method;
4249 enum {
4250 AUTH_TYPE_NONE,
4251 AUTH_TYPE_PUBLICKEY,
4252 AUTH_TYPE_PUBLICKEY_OFFER_LOUD,
4253 AUTH_TYPE_PUBLICKEY_OFFER_QUIET,
4254 AUTH_TYPE_PASSWORD,
4255 AUTH_TYPE_KEYBOARD_INTERACTIVE,
4256 AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET
4257 } type;
4258 int gotit, need_pw, can_pubkey, can_passwd, can_keyb_inter;
4259 int tried_pubkey_config, tried_agent, tried_keyb_inter;
4260 int kbd_inter_running;
4261 int we_are_in;
4262 int num_prompts, curr_prompt, echo;
4263 char username[100];
4264 int got_username;
4265 char pwprompt[200];
4266 char password[100];
4267 void *publickey_blob;
4268 int publickey_bloblen;
4269 unsigned char request[5], *response, *p;
4270 int responselen;
4271 int keyi, nkeys;
4272 int authed;
4273 char *pkblob, *alg, *commentp;
4274 int pklen, alglen, commentlen;
4275 int siglen, retlen, len;
4276 char *q, *agentreq, *ret;
4277 int try_send;
4278 };
4279 crState(do_ssh2_authconn_state);
4280
4281 crBegin(ssh->do_ssh2_authconn_crstate);
4282
4283 /*
4284 * Request userauth protocol, and await a response to it.
4285 */
4286 ssh2_pkt_init(ssh, SSH2_MSG_SERVICE_REQUEST);
4287 ssh2_pkt_addstring(ssh, "ssh-userauth");
4288 ssh2_pkt_send(ssh);
4289 crWaitUntilV(ispkt);
4290 if (ssh->pktin.type != SSH2_MSG_SERVICE_ACCEPT) {
4291 bombout((ssh,"Server refused user authentication protocol"));
4292 crReturnV;
4293 }
4294
4295 /*
4296 * We repeat this whole loop, including the username prompt,
4297 * until we manage a successful authentication. If the user
4298 * types the wrong _password_, they can be sent back to the
4299 * beginning to try another username, if this is configured on.
4300 * (If they specify a username in the config, they are never
4301 * asked, even if they do give a wrong password.)
4302 *
4303 * I think this best serves the needs of
4304 *
4305 * - the people who have no configuration, no keys, and just
4306 * want to try repeated (username,password) pairs until they
4307 * type both correctly
4308 *
4309 * - people who have keys and configuration but occasionally
4310 * need to fall back to passwords
4311 *
4312 * - people with a key held in Pageant, who might not have
4313 * logged in to a particular machine before; so they want to
4314 * type a username, and then _either_ their key will be
4315 * accepted, _or_ they will type a password. If they mistype
4316 * the username they will want to be able to get back and
4317 * retype it!
4318 */
4319 s->username[0] = '\0';
4320 s->got_username = FALSE;
4321 do {
4322 /*
4323 * Get a username.
4324 */
4325 if (s->got_username && !ssh->cfg.change_username) {
4326 /*
4327 * We got a username last time round this loop, and
4328 * with change_username turned off we don't try to get
4329 * it again.
4330 */
4331 } else if ((flags & FLAG_INTERACTIVE) && !*ssh->cfg.username) {
4332 if (ssh_get_line && !ssh_getline_pw_only) {
4333 if (!ssh_get_line("login as: ",
4334 s->username, sizeof(s->username), FALSE)) {
4335 /*
4336 * get_line failed to get a username.
4337 * Terminate.
4338 */
4339 logevent("No username provided. Abandoning session.");
4340 ssh->state = SSH_STATE_CLOSED;
4341 crReturnV;
4342 }
4343 } else {
4344 int ret; /* need not be saved across crReturn */
4345 c_write_str(ssh, "login as: ");
4346 ssh->send_ok = 1;
4347 setup_userpass_input(ssh, s->username, sizeof(s->username), 1);
4348 do {
4349 crWaitUntilV(!ispkt);
4350 ret = process_userpass_input(ssh, in, inlen);
4351 } while (ret == 0);
4352 if (ret < 0)
4353 cleanup_exit(0);
4354 c_write_str(ssh, "\r\n");
4355 }
4356 s->username[strcspn(s->username, "\n\r")] = '\0';
4357 } else {
4358 char *stuff;
4359 strncpy(s->username, ssh->cfg.username, sizeof(s->username));
4360 s->username[sizeof(s->username)-1] = '\0';
4361 if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
4362 stuff = dupprintf("Using username \"%s\".\r\n", s->username);
4363 c_write_str(ssh, stuff);
4364 sfree(stuff);
4365 }
4366 }
4367 s->got_username = TRUE;
4368
4369 /*
4370 * Send an authentication request using method "none": (a)
4371 * just in case it succeeds, and (b) so that we know what
4372 * authentication methods we can usefully try next.
4373 */
4374 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4375
4376 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4377 ssh2_pkt_addstring(ssh, s->username);
4378 ssh2_pkt_addstring(ssh, "ssh-connection");/* service requested */
4379 ssh2_pkt_addstring(ssh, "none"); /* method */
4380 ssh2_pkt_send(ssh);
4381 s->type = AUTH_TYPE_NONE;
4382 s->gotit = FALSE;
4383 s->we_are_in = FALSE;
4384
4385 s->tried_pubkey_config = FALSE;
4386 s->tried_agent = FALSE;
4387 s->tried_keyb_inter = FALSE;
4388 s->kbd_inter_running = FALSE;
4389 /* Load the pub half of ssh->cfg.keyfile so we notice if it's in Pageant */
4390 if (*ssh->cfg.keyfile) {
4391 int keytype;
4392 logeventf(ssh, "Reading private key file \"%.150s\"", ssh->cfg.keyfile);
4393 keytype = key_type(ssh->cfg.keyfile);
4394 if (keytype == SSH_KEYTYPE_SSH2) {
4395 s->publickey_blob =
4396 ssh2_userkey_loadpub(ssh->cfg.keyfile, NULL,
4397 &s->publickey_bloblen);
4398 } else {
4399 char *msgbuf;
4400 logeventf(ssh, "Unable to use this key file (%s)",
4401 key_type_to_str(keytype));
4402 msgbuf = dupprintf("Unable to use key file \"%.150s\""
4403 " (%s)\r\n", ssh->cfg.keyfile,
4404 key_type_to_str(keytype));
4405 c_write_str(ssh, msgbuf);
4406 sfree(msgbuf);
4407 s->publickey_blob = NULL;
4408 }
4409 } else
4410 s->publickey_blob = NULL;
4411
4412 while (1) {
4413 /*
4414 * Wait for the result of the last authentication request.
4415 */
4416 if (!s->gotit)
4417 crWaitUntilV(ispkt);
4418 while (ssh->pktin.type == SSH2_MSG_USERAUTH_BANNER) {
4419 char *banner;
4420 int size;
4421 /*
4422 * Don't show the banner if we're operating in
4423 * non-verbose non-interactive mode. (It's probably
4424 * a script, which means nobody will read the
4425 * banner _anyway_, and moreover the printing of
4426 * the banner will screw up processing on the
4427 * output of (say) plink.)
4428 */
4429 if (flags & (FLAG_VERBOSE | FLAG_INTERACTIVE)) {
4430 ssh2_pkt_getstring(ssh, &banner, &size);
4431 if (banner)
4432 c_write_untrusted(ssh, banner, size);
4433 }
4434 crWaitUntilV(ispkt);
4435 }
4436 if (ssh->pktin.type == SSH2_MSG_USERAUTH_SUCCESS) {
4437 logevent("Access granted");
4438 s->we_are_in = TRUE;
4439 break;
4440 }
4441
4442 if (s->kbd_inter_running &&
4443 ssh->pktin.type == SSH2_MSG_USERAUTH_INFO_REQUEST) {
4444 /*
4445 * This is either a further set-of-prompts packet
4446 * in keyboard-interactive authentication, or it's
4447 * the same one and we came back here with `gotit'
4448 * set. In the former case, we must reset the
4449 * curr_prompt variable.
4450 */
4451 if (!s->gotit)
4452 s->curr_prompt = 0;
4453 } else if (ssh->pktin.type != SSH2_MSG_USERAUTH_FAILURE) {
4454 bombout((ssh,"Strange packet received during authentication: type %d",
4455 ssh->pktin.type));
4456 crReturnV;
4457 }
4458
4459 s->gotit = FALSE;
4460
4461 /*
4462 * OK, we're now sitting on a USERAUTH_FAILURE message, so
4463 * we can look at the string in it and know what we can
4464 * helpfully try next.
4465 */
4466 if (ssh->pktin.type == SSH2_MSG_USERAUTH_FAILURE) {
4467 char *methods;
4468 int methlen;
4469 ssh2_pkt_getstring(ssh, &methods, &methlen);
4470 s->kbd_inter_running = FALSE;
4471 if (!ssh2_pkt_getbool(ssh)) {
4472 /*
4473 * We have received an unequivocal Access
4474 * Denied. This can translate to a variety of
4475 * messages:
4476 *
4477 * - if we'd just tried "none" authentication,
4478 * it's not worth printing anything at all
4479 *
4480 * - if we'd just tried a public key _offer_,
4481 * the message should be "Server refused our
4482 * key" (or no message at all if the key
4483 * came from Pageant)
4484 *
4485 * - if we'd just tried anything else, the
4486 * message really should be "Access denied".
4487 *
4488 * Additionally, if we'd just tried password
4489 * authentication, we should break out of this
4490 * whole loop so as to go back to the username
4491 * prompt.
4492 */
4493 if (s->type == AUTH_TYPE_NONE) {
4494 /* do nothing */
4495 } else if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD ||
4496 s->type == AUTH_TYPE_PUBLICKEY_OFFER_QUIET) {
4497 if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD)
4498 c_write_str(ssh, "Server refused our key\r\n");
4499 logevent("Server refused public key");
4500 } else if (s->type==AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET) {
4501 /* server declined keyboard-interactive; ignore */
4502 } else {
4503 c_write_str(ssh, "Access denied\r\n");
4504 logevent("Access denied");
4505 if (s->type == AUTH_TYPE_PASSWORD) {
4506 s->we_are_in = FALSE;
4507 break;
4508 }
4509 }
4510 } else {
4511 c_write_str(ssh, "Further authentication required\r\n");
4512 logevent("Further authentication required");
4513 }
4514
4515 s->can_pubkey =
4516 in_commasep_string("publickey", methods, methlen);
4517 s->can_passwd =
4518 in_commasep_string("password", methods, methlen);
4519 s->can_keyb_inter = ssh->cfg.try_ki_auth &&
4520 in_commasep_string("keyboard-interactive", methods, methlen);
4521 }
4522
4523 s->method = 0;
4524 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4525
4526 /*
4527 * Most password/passphrase prompts will be
4528 * non-echoing, so we set this to 0 by default.
4529 * Exception is that some keyboard-interactive prompts
4530 * can be echoing, in which case we'll set this to 1.
4531 */
4532 s->echo = 0;
4533
4534 if (!s->method && s->can_pubkey &&
4535 agent_exists() && !s->tried_agent) {
4536 /*
4537 * Attempt public-key authentication using Pageant.
4538 */
4539 void *r;
4540 s->authed = FALSE;
4541
4542 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4543 ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
4544
4545 s->tried_agent = TRUE;
4546
4547 logevent("Pageant is running. Requesting keys.");
4548
4549 /* Request the keys held by the agent. */
4550 PUT_32BIT(s->request, 1);
4551 s->request[4] = SSH2_AGENTC_REQUEST_IDENTITIES;
4552 agent_query(s->request, 5, &r, &s->responselen);
4553 s->response = (unsigned char *) r;
4554 if (s->response && s->responselen >= 5 &&
4555 s->response[4] == SSH2_AGENT_IDENTITIES_ANSWER) {
4556 s->p = s->response + 5;
4557 s->nkeys = GET_32BIT(s->p);
4558 s->p += 4;
4559 {
4560 char buf[64];
4561 sprintf(buf, "Pageant has %d SSH2 keys", s->nkeys);
4562 logevent(buf);
4563 }
4564 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
4565 void *vret;
4566
4567 {
4568 char buf[64];
4569 sprintf(buf, "Trying Pageant key #%d", s->keyi);
4570 logevent(buf);
4571 }
4572 s->pklen = GET_32BIT(s->p);
4573 s->p += 4;
4574 if (s->publickey_blob &&
4575 s->pklen == s->publickey_bloblen &&
4576 !memcmp(s->p, s->publickey_blob,
4577 s->publickey_bloblen)) {
4578 logevent("This key matches configured key file");
4579 s->tried_pubkey_config = 1;
4580 }
4581 s->pkblob = (char *)s->p;
4582 s->p += s->pklen;
4583 s->alglen = GET_32BIT(s->pkblob);
4584 s->alg = s->pkblob + 4;
4585 s->commentlen = GET_32BIT(s->p);
4586 s->p += 4;
4587 s->commentp = (char *)s->p;
4588 s->p += s->commentlen;
4589 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4590 ssh2_pkt_addstring(ssh, s->username);
4591 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4592 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4593 ssh2_pkt_addbool(ssh, FALSE); /* no signature included */
4594 ssh2_pkt_addstring_start(ssh);
4595 ssh2_pkt_addstring_data(ssh, s->alg, s->alglen);
4596 ssh2_pkt_addstring_start(ssh);
4597 ssh2_pkt_addstring_data(ssh, s->pkblob, s->pklen);
4598 ssh2_pkt_send(ssh);
4599
4600 crWaitUntilV(ispkt);
4601 if (ssh->pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
4602 logevent("Key refused");
4603 continue;
4604 }
4605
4606 if (flags & FLAG_VERBOSE) {
4607 c_write_str(ssh, "Authenticating with "
4608 "public key \"");
4609 c_write(ssh, s->commentp, s->commentlen);
4610 c_write_str(ssh, "\" from agent\r\n");
4611 }
4612
4613 /*
4614 * Server is willing to accept the key.
4615 * Construct a SIGN_REQUEST.
4616 */
4617 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4618 ssh2_pkt_addstring(ssh, s->username);
4619 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4620 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4621 ssh2_pkt_addbool(ssh, TRUE);
4622 ssh2_pkt_addstring_start(ssh);
4623 ssh2_pkt_addstring_data(ssh, s->alg, s->alglen);
4624 ssh2_pkt_addstring_start(ssh);
4625 ssh2_pkt_addstring_data(ssh, s->pkblob, s->pklen);
4626
4627 s->siglen = ssh->pktout.length - 5 + 4 + 20;
4628 s->len = 1; /* message type */
4629 s->len += 4 + s->pklen; /* key blob */
4630 s->len += 4 + s->siglen; /* data to sign */
4631 s->len += 4; /* flags */
4632 s->agentreq = smalloc(4 + s->len);
4633 PUT_32BIT(s->agentreq, s->len);
4634 s->q = s->agentreq + 4;
4635 *s->q++ = SSH2_AGENTC_SIGN_REQUEST;
4636 PUT_32BIT(s->q, s->pklen);
4637 s->q += 4;
4638 memcpy(s->q, s->pkblob, s->pklen);
4639 s->q += s->pklen;
4640 PUT_32BIT(s->q, s->siglen);
4641 s->q += 4;
4642 /* Now the data to be signed... */
4643 PUT_32BIT(s->q, 20);
4644 s->q += 4;
4645 memcpy(s->q, ssh->v2_session_id, 20);
4646 s->q += 20;
4647 memcpy(s->q, ssh->pktout.data + 5,
4648 ssh->pktout.length - 5);
4649 s->q += ssh->pktout.length - 5;
4650 /* And finally the (zero) flags word. */
4651 PUT_32BIT(s->q, 0);
4652 agent_query(s->agentreq, s->len + 4, &vret, &s->retlen);
4653 s->ret = vret;
4654 sfree(s->agentreq);
4655 if (s->ret) {
4656 if (s->ret[4] == SSH2_AGENT_SIGN_RESPONSE) {
4657 logevent("Sending Pageant's response");
4658 ssh2_add_sigblob(ssh, s->pkblob, s->pklen,
4659 s->ret + 9,
4660 GET_32BIT(s->ret + 5));
4661 ssh2_pkt_send(ssh);
4662 s->authed = TRUE;
4663 break;
4664 } else {
4665 logevent
4666 ("Pageant failed to answer challenge");
4667 sfree(s->ret);
4668 }
4669 }
4670 }
4671 if (s->authed)
4672 continue;
4673 }
4674 }
4675
4676 if (!s->method && s->can_pubkey && s->publickey_blob
4677 && !s->tried_pubkey_config) {
4678 unsigned char *pub_blob;
4679 char *algorithm, *comment;
4680 int pub_blob_len;
4681
4682 s->tried_pubkey_config = TRUE;
4683
4684 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4685 ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
4686
4687 /*
4688 * Try the public key supplied in the configuration.
4689 *
4690 * First, offer the public blob to see if the server is
4691 * willing to accept it.
4692 */
4693 pub_blob =
4694 (unsigned char *)ssh2_userkey_loadpub(ssh->cfg.keyfile,
4695 &algorithm,
4696 &pub_blob_len);
4697 if (pub_blob) {
4698 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4699 ssh2_pkt_addstring(ssh, s->username);
4700 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4701 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4702 ssh2_pkt_addbool(ssh, FALSE); /* no signature included */
4703 ssh2_pkt_addstring(ssh, algorithm);
4704 ssh2_pkt_addstring_start(ssh);
4705 ssh2_pkt_addstring_data(ssh, (char *)pub_blob,
4706 pub_blob_len);
4707 ssh2_pkt_send(ssh);
4708 logevent("Offered public key"); /* FIXME */
4709
4710 crWaitUntilV(ispkt);
4711 if (ssh->pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
4712 s->gotit = TRUE;
4713 s->type = AUTH_TYPE_PUBLICKEY_OFFER_LOUD;
4714 continue; /* key refused; give up on it */
4715 }
4716
4717 logevent("Offer of public key accepted");
4718 /*
4719 * Actually attempt a serious authentication using
4720 * the key.
4721 */
4722 if (ssh2_userkey_encrypted(ssh->cfg.keyfile, &comment)) {
4723 sprintf(s->pwprompt,
4724 "Passphrase for key \"%.100s\": ",
4725 comment);
4726 s->need_pw = TRUE;
4727 } else {
4728 s->need_pw = FALSE;
4729 }
4730 c_write_str(ssh, "Authenticating with public key \"");
4731 c_write_str(ssh, comment);
4732 c_write_str(ssh, "\"\r\n");
4733 s->method = AUTH_PUBLICKEY_FILE;
4734 }
4735 }
4736
4737 if (!s->method && s->can_keyb_inter && !s->tried_keyb_inter) {
4738 s->method = AUTH_KEYBOARD_INTERACTIVE;
4739 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
4740 s->tried_keyb_inter = TRUE;
4741
4742 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4743 ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;
4744
4745 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4746 ssh2_pkt_addstring(ssh, s->username);
4747 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4748 ssh2_pkt_addstring(ssh, "keyboard-interactive"); /* method */
4749 ssh2_pkt_addstring(ssh, ""); /* lang */
4750 ssh2_pkt_addstring(ssh, "");
4751 ssh2_pkt_send(ssh);
4752
4753 crWaitUntilV(ispkt);
4754 if (ssh->pktin.type != SSH2_MSG_USERAUTH_INFO_REQUEST) {
4755 if (ssh->pktin.type == SSH2_MSG_USERAUTH_FAILURE)
4756 s->gotit = TRUE;
4757 logevent("Keyboard-interactive authentication refused");
4758 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET;
4759 continue;
4760 }
4761
4762 s->kbd_inter_running = TRUE;
4763 s->curr_prompt = 0;
4764 }
4765
4766 if (s->kbd_inter_running) {
4767 s->method = AUTH_KEYBOARD_INTERACTIVE;
4768 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
4769 s->tried_keyb_inter = TRUE;
4770
4771 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4772 ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;
4773
4774 if (s->curr_prompt == 0) {
4775 /*
4776 * We've got a fresh USERAUTH_INFO_REQUEST.
4777 * Display header data, and start going through
4778 * the prompts.
4779 */
4780 char *name, *inst, *lang;
4781 int name_len, inst_len, lang_len;
4782
4783 ssh2_pkt_getstring(ssh, &name, &name_len);
4784 ssh2_pkt_getstring(ssh, &inst, &inst_len);
4785 ssh2_pkt_getstring(ssh, &lang, &lang_len);
4786 if (name_len > 0) {
4787 c_write_untrusted(ssh, name, name_len);
4788 c_write_str(ssh, "\r\n");
4789 }
4790 if (inst_len > 0) {
4791 c_write_untrusted(ssh, inst, inst_len);
4792 c_write_str(ssh, "\r\n");
4793 }
4794 s->num_prompts = ssh2_pkt_getuint32(ssh);
4795 }
4796
4797 /*
4798 * If there are prompts remaining in the packet,
4799 * display one and get a response.
4800 */
4801 if (s->curr_prompt < s->num_prompts) {
4802 char *prompt;
4803 int prompt_len;
4804
4805 ssh2_pkt_getstring(ssh, &prompt, &prompt_len);
4806 if (prompt_len > 0) {
4807 strncpy(s->pwprompt, prompt, sizeof(s->pwprompt));
4808 s->pwprompt[prompt_len < sizeof(s->pwprompt) ?
4809 prompt_len : sizeof(s->pwprompt)-1] = '\0';
4810 } else {
4811 strcpy(s->pwprompt,
4812 "<server failed to send prompt>: ");
4813 }
4814 s->echo = ssh2_pkt_getbool(ssh);
4815 s->need_pw = TRUE;
4816 } else
4817 s->need_pw = FALSE;
4818 }
4819
4820 if (!s->method && s->can_passwd) {
4821 s->method = AUTH_PASSWORD;
4822 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4823 ssh->pkt_ctx |= SSH2_PKTCTX_PASSWORD;
4824 sprintf(s->pwprompt, "%.90s@%.90s's password: ", s->username,
4825 ssh->savedhost);
4826 s->need_pw = TRUE;
4827 }
4828
4829 if (s->need_pw) {
4830 if (ssh_get_line) {
4831 if (!ssh_get_line(s->pwprompt, s->password,
4832 sizeof(s->password), TRUE)) {
4833 /*
4834 * get_line failed to get a password (for
4835 * example because one was supplied on the
4836 * command line which has already failed to
4837 * work). Terminate.
4838 */
4839 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
4840 ssh2_pkt_adduint32(ssh,SSH2_DISCONNECT_BY_APPLICATION);
4841 ssh2_pkt_addstring(ssh, "No more passwords available"
4842 " to try");
4843 ssh2_pkt_addstring(ssh, "en"); /* language tag */
4844 ssh2_pkt_send(ssh);
4845 logevent("Unable to authenticate");
4846 connection_fatal(ssh->frontend,
4847 "Unable to authenticate");
4848 ssh->state = SSH_STATE_CLOSED;
4849 crReturnV;
4850 }
4851 } else {
4852 int ret; /* need not be saved across crReturn */
4853 c_write_untrusted(ssh, s->pwprompt, strlen(s->pwprompt));
4854 ssh->send_ok = 1;
4855
4856 setup_userpass_input(ssh, s->password,
4857 sizeof(s->password), s->echo);
4858 do {
4859 crWaitUntilV(!ispkt);
4860 ret = process_userpass_input(ssh, in, inlen);
4861 } while (ret == 0);
4862 if (ret < 0)
4863 cleanup_exit(0);
4864 c_write_str(ssh, "\r\n");
4865 }
4866 }
4867
4868 if (s->method == AUTH_PUBLICKEY_FILE) {
4869 /*
4870 * We have our passphrase. Now try the actual authentication.
4871 */
4872 struct ssh2_userkey *key;
4873
4874 key = ssh2_load_userkey(ssh->cfg.keyfile, s->password);
4875 if (key == SSH2_WRONG_PASSPHRASE || key == NULL) {
4876 if (key == SSH2_WRONG_PASSPHRASE) {
4877 c_write_str(ssh, "Wrong passphrase\r\n");
4878 s->tried_pubkey_config = FALSE;
4879 } else {
4880 c_write_str(ssh, "Unable to load private key\r\n");
4881 s->tried_pubkey_config = TRUE;
4882 }
4883 /* Send a spurious AUTH_NONE to return to the top. */
4884 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4885 ssh2_pkt_addstring(ssh, s->username);
4886 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4887 ssh2_pkt_addstring(ssh, "none"); /* method */
4888 ssh2_pkt_send(ssh);
4889 s->type = AUTH_TYPE_NONE;
4890 } else {
4891 unsigned char *pkblob, *sigblob, *sigdata;
4892 int pkblob_len, sigblob_len, sigdata_len;
4893
4894 /*
4895 * We have loaded the private key and the server
4896 * has announced that it's willing to accept it.
4897 * Hallelujah. Generate a signature and send it.
4898 */
4899 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4900 ssh2_pkt_addstring(ssh, s->username);
4901 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4902 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4903 ssh2_pkt_addbool(ssh, TRUE);
4904 ssh2_pkt_addstring(ssh, key->alg->name);
4905 pkblob = key->alg->public_blob(key->data, &pkblob_len);
4906 ssh2_pkt_addstring_start(ssh);
4907 ssh2_pkt_addstring_data(ssh, (char *)pkblob, pkblob_len);
4908
4909 /*
4910 * The data to be signed is:
4911 *
4912 * string session-id
4913 *
4914 * followed by everything so far placed in the
4915 * outgoing packet.
4916 */
4917 sigdata_len = ssh->pktout.length - 5 + 4 + 20;
4918 sigdata = smalloc(sigdata_len);
4919 PUT_32BIT(sigdata, 20);
4920 memcpy(sigdata + 4, ssh->v2_session_id, 20);
4921 memcpy(sigdata + 24, ssh->pktout.data + 5,
4922 ssh->pktout.length - 5);
4923 sigblob = key->alg->sign(key->data, (char *)sigdata,
4924 sigdata_len, &sigblob_len);
4925 ssh2_add_sigblob(ssh, pkblob, pkblob_len,
4926 sigblob, sigblob_len);
4927 sfree(pkblob);
4928 sfree(sigblob);
4929 sfree(sigdata);
4930
4931 ssh2_pkt_send(ssh);
4932 s->type = AUTH_TYPE_PUBLICKEY;
4933 }
4934 } else if (s->method == AUTH_PASSWORD) {
4935 /*
4936 * We send the password packet lumped tightly together with
4937 * an SSH_MSG_IGNORE packet. The IGNORE packet contains a
4938 * string long enough to make the total length of the two
4939 * packets constant. This should ensure that a passive
4940 * listener doing traffic analyis can't work out the length
4941 * of the password.
4942 *
4943 * For this to work, we need an assumption about the
4944 * maximum length of the password packet. I think 256 is
4945 * pretty conservative. Anyone using a password longer than
4946 * that probably doesn't have much to worry about from
4947 * people who find out how long their password is!
4948 */
4949 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4950 ssh2_pkt_addstring(ssh, s->username);
4951 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4952 ssh2_pkt_addstring(ssh, "password");
4953 ssh2_pkt_addbool(ssh, FALSE);
4954 ssh2_pkt_addstring(ssh, s->password);
4955 memset(s->password, 0, sizeof(s->password));
4956 ssh2_pkt_defer(ssh);
4957 /*
4958 * We'll include a string that's an exact multiple of the
4959 * cipher block size. If the cipher is NULL for some
4960 * reason, we don't do this trick at all because we gain
4961 * nothing by it.
4962 */
4963 if (ssh->cscipher) {
4964 int stringlen, i;
4965
4966 stringlen = (256 - ssh->deferred_len);
4967 stringlen += ssh->cscipher->blksize - 1;
4968 stringlen -= (stringlen % ssh->cscipher->blksize);
4969 if (ssh->cscomp) {
4970 /*
4971 * Temporarily disable actual compression,
4972 * so we can guarantee to get this string
4973 * exactly the length we want it. The
4974 * compression-disabling routine should
4975 * return an integer indicating how many
4976 * bytes we should adjust our string length
4977 * by.
4978 */
4979 stringlen -=
4980 ssh->cscomp->disable_compression(ssh->cs_comp_ctx);
4981 }
4982 ssh2_pkt_init(ssh, SSH2_MSG_IGNORE);
4983 ssh2_pkt_addstring_start(ssh);
4984 for (i = 0; i < stringlen; i++) {
4985 char c = (char) random_byte();
4986 ssh2_pkt_addstring_data(ssh, &c, 1);
4987 }
4988 ssh2_pkt_defer(ssh);
4989 }
4990 ssh_pkt_defersend(ssh);
4991 logevent("Sent password");
4992 s->type = AUTH_TYPE_PASSWORD;
4993 } else if (s->method == AUTH_KEYBOARD_INTERACTIVE) {
4994 if (s->curr_prompt == 0) {
4995 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_INFO_RESPONSE);
4996 ssh2_pkt_adduint32(ssh, s->num_prompts);
4997 }
4998 if (s->need_pw) { /* only add pw if we just got one! */
4999 ssh2_pkt_addstring(ssh, s->password);
5000 memset(s->password, 0, sizeof(s->password));
5001 s->curr_prompt++;
5002 }
5003 if (s->curr_prompt >= s->num_prompts) {
5004 ssh2_pkt_send(ssh);
5005 } else {
5006 /*
5007 * If there are prompts remaining, we set
5008 * `gotit' so that we won't attempt to get
5009 * another packet. Then we go back round the
5010 * loop and will end up retrieving another
5011 * prompt out of the existing packet. Funky or
5012 * what?
5013 */
5014 s->gotit = TRUE;
5015 }
5016 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
5017 } else {
5018 c_write_str(ssh, "No supported authentication methods"
5019 " left to try!\r\n");
5020 logevent("No supported authentications offered."
5021 " Disconnecting");
5022 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5023 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5024 ssh2_pkt_addstring(ssh, "No supported authentication"
5025 " methods available");
5026 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5027 ssh2_pkt_send(ssh);
5028 ssh->state = SSH_STATE_CLOSED;
5029 crReturnV;
5030 }
5031 }
5032 } while (!s->we_are_in);
5033
5034 /*
5035 * Now we're authenticated for the connection protocol. The
5036 * connection protocol will automatically have started at this
5037 * point; there's no need to send SERVICE_REQUEST.
5038 */
5039
5040 /*
5041 * So now create a channel with a session in it.
5042 */
5043 ssh->channels = newtree234(ssh_channelcmp);
5044 ssh->mainchan = smalloc(sizeof(struct ssh_channel));
5045 ssh->mainchan->ssh = ssh;
5046 ssh->mainchan->localid = alloc_channel_id(ssh);
5047 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN);
5048 ssh2_pkt_addstring(ssh, "session");
5049 ssh2_pkt_adduint32(ssh, ssh->mainchan->localid);
5050 ssh->mainchan->v.v2.locwindow = OUR_V2_WINSIZE;
5051 ssh2_pkt_adduint32(ssh, ssh->mainchan->v.v2.locwindow);/* our window size */
5052 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
5053 ssh2_pkt_send(ssh);
5054 crWaitUntilV(ispkt);
5055 if (ssh->pktin.type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
5056 bombout((ssh,"Server refused to open a session"));
5057 crReturnV;
5058 /* FIXME: error data comes back in FAILURE packet */
5059 }
5060 if (ssh2_pkt_getuint32(ssh) != ssh->mainchan->localid) {
5061 bombout((ssh,"Server's channel confirmation cited wrong channel"));
5062 crReturnV;
5063 }
5064 ssh->mainchan->remoteid = ssh2_pkt_getuint32(ssh);
5065 ssh->mainchan->type = CHAN_MAINSESSION;
5066 ssh->mainchan->closes = 0;
5067 ssh->mainchan->v.v2.remwindow = ssh2_pkt_getuint32(ssh);
5068 ssh->mainchan->v.v2.remmaxpkt = ssh2_pkt_getuint32(ssh);
5069 bufchain_init(&ssh->mainchan->v.v2.outbuffer);
5070 add234(ssh->channels, ssh->mainchan);
5071 logevent("Opened channel for session");
5072
5073 /*
5074 * Potentially enable X11 forwarding.
5075 */
5076 if (ssh->cfg.x11_forward) {
5077 char proto[20], data[64];
5078 logevent("Requesting X11 forwarding");
5079 ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
5080 data, sizeof(data), ssh->cfg.x11_auth);
5081 x11_get_real_auth(ssh->x11auth, ssh->cfg.x11_display);
5082 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5083 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
5084 ssh2_pkt_addstring(ssh, "x11-req");
5085 ssh2_pkt_addbool(ssh, 1); /* want reply */
5086 ssh2_pkt_addbool(ssh, 0); /* many connections */
5087 ssh2_pkt_addstring(ssh, proto);
5088 ssh2_pkt_addstring(ssh, data);
5089 ssh2_pkt_adduint32(ssh, x11_get_screen_number(ssh->cfg.x11_display));
5090 ssh2_pkt_send(ssh);
5091
5092 do {
5093 crWaitUntilV(ispkt);
5094 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5095 unsigned i = ssh2_pkt_getuint32(ssh);
5096 struct ssh_channel *c;
5097 c = find234(ssh->channels, &i, ssh_channelfind);
5098 if (!c)
5099 continue; /* nonexistent channel */
5100 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5101 }
5102 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5103
5104 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5105 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5106 bombout((ssh,"Unexpected response to X11 forwarding request:"
5107 " packet type %d", ssh->pktin.type));
5108 crReturnV;
5109 }
5110 logevent("X11 forwarding refused");
5111 } else {
5112 logevent("X11 forwarding enabled");
5113 ssh->X11_fwd_enabled = TRUE;
5114 }
5115 }
5116
5117 /*
5118 * Enable port forwardings.
5119 */
5120 {
5121 char type;
5122 int n;
5123 int sport,dport,sserv,dserv;
5124 char sports[256], dports[256], saddr[256], host[256];
5125
5126 ssh->rportfwds = newtree234(ssh_rportcmp_ssh2);
5127 /* Add port forwardings. */
5128 ssh->portfwd_strptr = ssh->cfg.portfwd;
5129 while (*ssh->portfwd_strptr) {
5130 type = *ssh->portfwd_strptr++;
5131 saddr[0] = '\0';
5132 n = 0;
5133 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != '\t') {
5134 if (*ssh->portfwd_strptr == ':') {
5135 /*
5136 * We've seen a colon in the middle of the
5137 * source port number. This means that
5138 * everything we've seen until now is the
5139 * source _address_, so we'll move it into
5140 * saddr and start sports from the beginning
5141 * again.
5142 */
5143 ssh->portfwd_strptr++;
5144 sports[n] = '\0';
5145 strcpy(saddr, sports);
5146 n = 0;
5147 }
5148 if (n < 255) sports[n++] = *ssh->portfwd_strptr++;
5149 }
5150 sports[n] = 0;
5151 if (*ssh->portfwd_strptr == '\t')
5152 ssh->portfwd_strptr++;
5153 n = 0;
5154 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':') {
5155 if (n < 255) host[n++] = *ssh->portfwd_strptr++;
5156 }
5157 host[n] = 0;
5158 if (*ssh->portfwd_strptr == ':')
5159 ssh->portfwd_strptr++;
5160 n = 0;
5161 while (*ssh->portfwd_strptr) {
5162 if (n < 255) dports[n++] = *ssh->portfwd_strptr++;
5163 }
5164 dports[n] = 0;
5165 ssh->portfwd_strptr++;
5166 dport = atoi(dports);
5167 dserv = 0;
5168 if (dport == 0) {
5169 dserv = 1;
5170 dport = net_service_lookup(dports);
5171 if (!dport) {
5172 logeventf(ssh, "Service lookup failed for destination"
5173 " port \"%s\"", dports);
5174 }
5175 }
5176 sport = atoi(sports);
5177 sserv = 0;
5178 if (sport == 0) {
5179 sserv = 1;
5180 sport = net_service_lookup(sports);
5181 if (!sport) {
5182 logeventf(ssh, "Service lookup failed for source"
5183 " port \"%s\"", sports);
5184 }
5185 }
5186 if (sport && dport) {
5187 if (type == 'L') {
5188 pfd_addforward(host, dport, *saddr ? saddr : NULL,
5189 sport, ssh, &ssh->cfg);
5190 logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
5191 " forwarding to %s:%.*s%.*s%d%.*s",
5192 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
5193 (int)(*saddr?1:0), ":",
5194 (int)(sserv ? strlen(sports) : 0), sports,
5195 sserv, "(", sport, sserv, ")",
5196 host,
5197 (int)(dserv ? strlen(dports) : 0), dports,
5198 dserv, "(", dport, dserv, ")");
5199 } else {
5200 struct ssh_rportfwd *pf;
5201 pf = smalloc(sizeof(*pf));
5202 strcpy(pf->dhost, host);
5203 pf->dport = dport;
5204 pf->sport = sport;
5205 if (add234(ssh->rportfwds, pf) != pf) {
5206 logeventf(ssh, "Duplicate remote port forwarding"
5207 " to %s:%d", host, dport);
5208 sfree(pf);
5209 } else {
5210 logeventf(ssh, "Requesting remote port "
5211 "%.*s%.*s%.*s%.*s%d%.*s"
5212 " forward to %s:%.*s%.*s%d%.*s",
5213 (int)(*saddr?strlen(saddr):0),
5214 *saddr?saddr:NULL,
5215 (int)(*saddr?1:0), ":",
5216 (int)(sserv ? strlen(sports) : 0), sports,
5217 sserv, "(", sport, sserv, ")",
5218 host,
5219 (int)(dserv ? strlen(dports) : 0), dports,
5220 dserv, "(", dport, dserv, ")");
5221 ssh2_pkt_init(ssh, SSH2_MSG_GLOBAL_REQUEST);
5222 ssh2_pkt_addstring(ssh, "tcpip-forward");
5223 ssh2_pkt_addbool(ssh, 1);/* want reply */
5224 if (*saddr)
5225 ssh2_pkt_addstring(ssh, saddr);
5226 if (ssh->cfg.rport_acceptall)
5227 ssh2_pkt_addstring(ssh, "0.0.0.0");
5228 else
5229 ssh2_pkt_addstring(ssh, "127.0.0.1");
5230 ssh2_pkt_adduint32(ssh, sport);
5231 ssh2_pkt_send(ssh);
5232
5233 do {
5234 crWaitUntilV(ispkt);
5235 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5236 unsigned i = ssh2_pkt_getuint32(ssh);
5237 struct ssh_channel *c;
5238 c = find234(ssh->channels, &i, ssh_channelfind);
5239 if (!c)
5240 continue;/* nonexistent channel */
5241 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5242 }
5243 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5244
5245 if (ssh->pktin.type != SSH2_MSG_REQUEST_SUCCESS) {
5246 if (ssh->pktin.type != SSH2_MSG_REQUEST_FAILURE) {
5247 bombout((ssh,"Unexpected response to port "
5248 "forwarding request: packet type %d",
5249 ssh->pktin.type));
5250 crReturnV;
5251 }
5252 logevent("Server refused this port forwarding");
5253 } else {
5254 logevent("Remote port forwarding enabled");
5255 }
5256 }
5257 }
5258 }
5259 }
5260 }
5261
5262 /*
5263 * Potentially enable agent forwarding.
5264 */
5265 if (ssh->cfg.agentfwd && agent_exists()) {
5266 logevent("Requesting OpenSSH-style agent forwarding");
5267 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5268 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
5269 ssh2_pkt_addstring(ssh, "auth-agent-req@openssh.com");
5270 ssh2_pkt_addbool(ssh, 1); /* want reply */
5271 ssh2_pkt_send(ssh);
5272
5273 do {
5274 crWaitUntilV(ispkt);
5275 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5276 unsigned i = ssh2_pkt_getuint32(ssh);
5277 struct ssh_channel *c;
5278 c = find234(ssh->channels, &i, ssh_channelfind);
5279 if (!c)
5280 continue; /* nonexistent channel */
5281 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5282 }
5283 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5284
5285 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5286 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5287 bombout((ssh,"Unexpected response to agent forwarding request:"
5288 " packet type %d", ssh->pktin.type));
5289 crReturnV;
5290 }
5291 logevent("Agent forwarding refused");
5292 } else {
5293 logevent("Agent forwarding enabled");
5294 ssh->agentfwd_enabled = TRUE;
5295 }
5296 }
5297
5298 /*
5299 * Now allocate a pty for the session.
5300 */
5301 if (!ssh->cfg.nopty) {
5302 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5303 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid); /* recipient channel */
5304 ssh2_pkt_addstring(ssh, "pty-req");
5305 ssh2_pkt_addbool(ssh, 1); /* want reply */
5306 ssh2_pkt_addstring(ssh, ssh->cfg.termtype);
5307 ssh2_pkt_adduint32(ssh, ssh->term_width);
5308 ssh2_pkt_adduint32(ssh, ssh->term_height);
5309 ssh2_pkt_adduint32(ssh, 0); /* pixel width */
5310 ssh2_pkt_adduint32(ssh, 0); /* pixel height */
5311 ssh2_pkt_addstring_start(ssh);
5312 ssh2_pkt_addstring_data(ssh, "\0", 1); /* TTY_OP_END, no special options */
5313 ssh2_pkt_send(ssh);
5314 ssh->state = SSH_STATE_INTERMED;
5315
5316 do {
5317 crWaitUntilV(ispkt);
5318 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5319 unsigned i = ssh2_pkt_getuint32(ssh);
5320 struct ssh_channel *c;
5321 c = find234(ssh->channels, &i, ssh_channelfind);
5322 if (!c)
5323 continue; /* nonexistent channel */
5324 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5325 }
5326 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5327
5328 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5329 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5330 bombout((ssh,"Unexpected response to pty request:"
5331 " packet type %d", ssh->pktin.type));
5332 crReturnV;
5333 }
5334 c_write_str(ssh, "Server refused to allocate pty\r\n");
5335 ssh->editing = ssh->echoing = 1;
5336 } else {
5337 logevent("Allocated pty");
5338 }
5339 } else {
5340 ssh->editing = ssh->echoing = 1;
5341 }
5342
5343 /*
5344 * Start a shell or a remote command. We may have to attempt
5345 * this twice if the config data has provided a second choice
5346 * of command.
5347 */
5348 while (1) {
5349 int subsys;
5350 char *cmd;
5351
5352 if (ssh->fallback_cmd) {
5353 subsys = ssh->cfg.ssh_subsys2;
5354 cmd = ssh->cfg.remote_cmd_ptr2;
5355 } else {
5356 subsys = ssh->cfg.ssh_subsys;
5357 cmd = ssh->cfg.remote_cmd_ptr;
5358 }
5359
5360 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5361 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid); /* recipient channel */
5362 if (subsys) {
5363 ssh2_pkt_addstring(ssh, "subsystem");
5364 ssh2_pkt_addbool(ssh, 1); /* want reply */
5365 ssh2_pkt_addstring(ssh, cmd);
5366 } else if (*cmd) {
5367 ssh2_pkt_addstring(ssh, "exec");
5368 ssh2_pkt_addbool(ssh, 1); /* want reply */
5369 ssh2_pkt_addstring(ssh, cmd);
5370 } else {
5371 ssh2_pkt_addstring(ssh, "shell");
5372 ssh2_pkt_addbool(ssh, 1); /* want reply */
5373 }
5374 ssh2_pkt_send(ssh);
5375 do {
5376 crWaitUntilV(ispkt);
5377 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5378 unsigned i = ssh2_pkt_getuint32(ssh);
5379 struct ssh_channel *c;
5380 c = find234(ssh->channels, &i, ssh_channelfind);
5381 if (!c)
5382 continue; /* nonexistent channel */
5383 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5384 }
5385 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5386 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5387 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5388 bombout((ssh,"Unexpected response to shell/command request:"
5389 " packet type %d", ssh->pktin.type));
5390 crReturnV;
5391 }
5392 /*
5393 * We failed to start the command. If this is the
5394 * fallback command, we really are finished; if it's
5395 * not, and if the fallback command exists, try falling
5396 * back to it before complaining.
5397 */
5398 if (!ssh->fallback_cmd && ssh->cfg.remote_cmd_ptr2 != NULL) {
5399 logevent("Primary command failed; attempting fallback");
5400 ssh->fallback_cmd = TRUE;
5401 continue;
5402 }
5403 bombout((ssh,"Server refused to start a shell/command"));
5404 crReturnV;
5405 } else {
5406 logevent("Started a shell/command");
5407 }
5408 break;
5409 }
5410
5411 ssh->state = SSH_STATE_SESSION;
5412 if (ssh->size_needed)
5413 ssh_size(ssh, ssh->term_width, ssh->term_height);
5414 if (ssh->eof_needed)
5415 ssh_special(ssh, TS_EOF);
5416
5417 /*
5418 * Transfer data!
5419 */
5420 if (ssh->ldisc)
5421 ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */
5422 ssh->send_ok = 1;
5423 while (1) {
5424 crReturnV;
5425 s->try_send = FALSE;
5426 if (ispkt) {
5427 if (ssh->pktin.type == SSH2_MSG_CHANNEL_DATA ||
5428 ssh->pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA) {
5429 char *data;
5430 int length;
5431 unsigned i = ssh2_pkt_getuint32(ssh);
5432 struct ssh_channel *c;
5433 c = find234(ssh->channels, &i, ssh_channelfind);
5434 if (!c)
5435 continue; /* nonexistent channel */
5436 if (ssh->pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
5437 ssh2_pkt_getuint32(ssh) != SSH2_EXTENDED_DATA_STDERR)
5438 continue; /* extended but not stderr */
5439 ssh2_pkt_getstring(ssh, &data, &length);
5440 if (data) {
5441 int bufsize;
5442 c->v.v2.locwindow -= length;
5443 switch (c->type) {
5444 case CHAN_MAINSESSION:
5445 bufsize =
5446 from_backend(ssh->frontend, ssh->pktin.type ==
5447 SSH2_MSG_CHANNEL_EXTENDED_DATA,
5448 data, length);
5449 break;
5450 case CHAN_X11:
5451 bufsize = x11_send(c->u.x11.s, data, length);
5452 break;
5453 case CHAN_SOCKDATA:
5454 bufsize = pfd_send(c->u.pfd.s, data, length);
5455 break;
5456 case CHAN_AGENT:
5457 while (length > 0) {
5458 if (c->u.a.lensofar < 4) {
5459 int l = min(4 - c->u.a.lensofar, length);
5460 memcpy(c->u.a.msglen + c->u.a.lensofar,
5461 data, l);
5462 data += l;
5463 length -= l;
5464 c->u.a.lensofar += l;
5465 }
5466 if (c->u.a.lensofar == 4) {
5467 c->u.a.totallen =
5468 4 + GET_32BIT(c->u.a.msglen);
5469 c->u.a.message = smalloc(c->u.a.totallen);
5470 memcpy(c->u.a.message, c->u.a.msglen, 4);
5471 }
5472 if (c->u.a.lensofar >= 4 && length > 0) {
5473 int l =
5474 min(c->u.a.totallen - c->u.a.lensofar,
5475 length);
5476 memcpy(c->u.a.message + c->u.a.lensofar,
5477 data, l);
5478 data += l;
5479 length -= l;
5480 c->u.a.lensofar += l;
5481 }
5482 if (c->u.a.lensofar == c->u.a.totallen) {
5483 void *reply, *sentreply;
5484 int replylen;
5485 agent_query(c->u.a.message,
5486 c->u.a.totallen, &reply,
5487 &replylen);
5488 if (reply)
5489 sentreply = reply;
5490 else {
5491 /* Fake SSH_AGENT_FAILURE. */
5492 sentreply = "\0\0\0\1\5";
5493 replylen = 5;
5494 }
5495 ssh2_add_channel_data(c, sentreply, replylen);
5496 s->try_send = TRUE;
5497 if (reply)
5498 sfree(reply);
5499 sfree(c->u.a.message);
5500 c->u.a.lensofar = 0;
5501 }
5502 }
5503 bufsize = 0;
5504 break;
5505 }
5506 /*
5507 * If we are not buffering too much data,
5508 * enlarge the window again at the remote side.
5509 */
5510 if (bufsize < OUR_V2_WINSIZE)
5511 ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
5512 }
5513 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_EOF) {
5514 unsigned i = ssh2_pkt_getuint32(ssh);
5515 struct ssh_channel *c;
5516
5517 c = find234(ssh->channels, &i, ssh_channelfind);
5518 if (!c)
5519 continue; /* nonexistent channel */
5520
5521 if (c->type == CHAN_X11) {
5522 /*
5523 * Remote EOF on an X11 channel means we should
5524 * wrap up and close the channel ourselves.
5525 */
5526 x11_close(c->u.x11.s);
5527 sshfwd_close(c);
5528 } else if (c->type == CHAN_AGENT) {
5529 sshfwd_close(c);
5530 } else if (c->type == CHAN_SOCKDATA) {
5531 pfd_close(c->u.pfd.s);
5532 sshfwd_close(c);
5533 }
5534 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_CLOSE) {
5535 unsigned i = ssh2_pkt_getuint32(ssh);
5536 struct ssh_channel *c;
5537
5538 c = find234(ssh->channels, &i, ssh_channelfind);
5539 if (!c || ((int)c->remoteid) == -1) {
5540 bombout((ssh,"Received CHANNEL_CLOSE for %s channel %d\n",
5541 c ? "half-open" : "nonexistent", i));
5542 }
5543 /* Do pre-close processing on the channel. */
5544 switch (c->type) {
5545 case CHAN_MAINSESSION:
5546 break; /* nothing to see here, move along */
5547 case CHAN_X11:
5548 if (c->u.x11.s != NULL)
5549 x11_close(c->u.x11.s);
5550 sshfwd_close(c);
5551 break;
5552 case CHAN_AGENT:
5553 sshfwd_close(c);
5554 break;
5555 case CHAN_SOCKDATA:
5556 if (c->u.pfd.s != NULL)
5557 pfd_close(c->u.pfd.s);
5558 sshfwd_close(c);
5559 break;
5560 }
5561 if (c->closes == 0) {
5562 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
5563 ssh2_pkt_adduint32(ssh, c->remoteid);
5564 ssh2_pkt_send(ssh);
5565 }
5566 del234(ssh->channels, c);
5567 bufchain_clear(&c->v.v2.outbuffer);
5568 sfree(c);
5569
5570 /*
5571 * See if that was the last channel left open.
5572 */
5573 if (count234(ssh->channels) == 0) {
5574 #if 0
5575 /*
5576 * We used to send SSH_MSG_DISCONNECT here,
5577 * because I'd believed that _every_ conforming
5578 * SSH2 connection had to end with a disconnect
5579 * being sent by at least one side; apparently
5580 * I was wrong and it's perfectly OK to
5581 * unceremoniously slam the connection shut
5582 * when you're done, and indeed OpenSSH feels
5583 * this is more polite than sending a
5584 * DISCONNECT. So now we don't.
5585 */
5586 logevent("All channels closed. Disconnecting");
5587 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5588 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5589 ssh2_pkt_addstring(ssh, "All open channels closed");
5590 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5591 ssh2_pkt_send(ssh);
5592 #endif
5593 ssh->state = SSH_STATE_CLOSED;
5594 crReturnV;
5595 }
5596 continue; /* remote sends close; ignore (FIXME) */
5597 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5598 unsigned i = ssh2_pkt_getuint32(ssh);
5599 struct ssh_channel *c;
5600 c = find234(ssh->channels, &i, ssh_channelfind);
5601 if (!c || c->closes)
5602 continue; /* nonexistent or closing channel */
5603 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5604 s->try_send = TRUE;
5605 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
5606 unsigned i = ssh2_pkt_getuint32(ssh);
5607 struct ssh_channel *c;
5608 c = find234(ssh->channels, &i, ssh_channelfind);
5609 if (!c)
5610 continue; /* nonexistent channel */
5611 if (c->type != CHAN_SOCKDATA_DORMANT)
5612 continue; /* dunno why they're confirming this */
5613 c->remoteid = ssh2_pkt_getuint32(ssh);
5614 c->type = CHAN_SOCKDATA;
5615 c->v.v2.remwindow = ssh2_pkt_getuint32(ssh);
5616 c->v.v2.remmaxpkt = ssh2_pkt_getuint32(ssh);
5617 if (c->u.pfd.s)
5618 pfd_confirm(c->u.pfd.s);
5619 if (c->closes) {
5620 /*
5621 * We have a pending close on this channel,
5622 * which we decided on before the server acked
5623 * the channel open. So now we know the
5624 * remoteid, we can close it again.
5625 */
5626 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
5627 ssh2_pkt_adduint32(ssh, c->remoteid);
5628 ssh2_pkt_send(ssh);
5629 }
5630 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN_FAILURE) {
5631 unsigned i = ssh2_pkt_getuint32(ssh);
5632 struct ssh_channel *c;
5633 c = find234(ssh->channels, &i, ssh_channelfind);
5634 if (!c)
5635 continue; /* nonexistent channel */
5636 if (c->type != CHAN_SOCKDATA_DORMANT)
5637 continue; /* dunno why they're failing this */
5638
5639 logevent("Forwarded connection refused by server");
5640
5641 pfd_close(c->u.pfd.s);
5642
5643 del234(ssh->channels, c);
5644 sfree(c);
5645 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_REQUEST) {
5646 unsigned localid;
5647 char *type;
5648 int typelen, want_reply;
5649 struct ssh_channel *c;
5650
5651 localid = ssh2_pkt_getuint32(ssh);
5652 ssh2_pkt_getstring(ssh, &type, &typelen);
5653 want_reply = ssh2_pkt_getbool(ssh);
5654
5655 /*
5656 * First, check that the channel exists. Otherwise,
5657 * we can instantly disconnect with a rude message.
5658 */
5659 c = find234(ssh->channels, &localid, ssh_channelfind);
5660 if (!c) {
5661 char buf[80];
5662 sprintf(buf, "Received channel request for nonexistent"
5663 " channel %d", localid);
5664 logevent(buf);
5665 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5666 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5667 ssh2_pkt_addstring(ssh, buf);
5668 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5669 ssh2_pkt_send(ssh);
5670 connection_fatal("%s", buf);
5671 ssh->state = SSH_STATE_CLOSED;
5672 crReturnV;
5673 }
5674
5675 /*
5676 * Having got the channel number, we now look at
5677 * the request type string to see if it's something
5678 * we recognise.
5679 */
5680 if (typelen == 11 && !memcmp(type, "exit-status", 11) &&
5681 c == ssh->mainchan) {
5682 /* We recognise "exit-status" on the primary channel. */
5683 char buf[100];
5684 ssh->exitcode = ssh2_pkt_getuint32(ssh);
5685 sprintf(buf, "Server sent command exit status %d",
5686 ssh->exitcode);
5687 logevent(buf);
5688 if (want_reply) {
5689 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_SUCCESS);
5690 ssh2_pkt_adduint32(ssh, c->remoteid);
5691 ssh2_pkt_send(ssh);
5692 }
5693 } else {
5694 /*
5695 * This is a channel request we don't know
5696 * about, so we now either ignore the request
5697 * or respond with CHANNEL_FAILURE, depending
5698 * on want_reply.
5699 */
5700 if (want_reply) {
5701 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_FAILURE);
5702 ssh2_pkt_adduint32(ssh, c->remoteid);
5703 ssh2_pkt_send(ssh);
5704 }
5705 }
5706 } else if (ssh->pktin.type == SSH2_MSG_GLOBAL_REQUEST) {
5707 char *type;
5708 int typelen, want_reply;
5709
5710 ssh2_pkt_getstring(ssh, &type, &typelen);
5711 want_reply = ssh2_pkt_getbool(ssh);
5712
5713 /*
5714 * We currently don't support any global requests
5715 * at all, so we either ignore the request or
5716 * respond with REQUEST_FAILURE, depending on
5717 * want_reply.
5718 */
5719 if (want_reply) {
5720 ssh2_pkt_init(ssh, SSH2_MSG_REQUEST_FAILURE);
5721 ssh2_pkt_send(ssh);
5722 }
5723 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN) {
5724 char *type;
5725 int typelen;
5726 char *peeraddr;
5727 int peeraddrlen;
5728 int port;
5729 char *error = NULL;
5730 struct ssh_channel *c;
5731 unsigned remid, winsize, pktsize;
5732 ssh2_pkt_getstring(ssh, &type, &typelen);
5733 c = smalloc(sizeof(struct ssh_channel));
5734 c->ssh = ssh;
5735
5736 remid = ssh2_pkt_getuint32(ssh);
5737 winsize = ssh2_pkt_getuint32(ssh);
5738 pktsize = ssh2_pkt_getuint32(ssh);
5739 ssh2_pkt_getstring(ssh, &peeraddr, &peeraddrlen);
5740 port = ssh2_pkt_getuint32(ssh);
5741
5742 if (typelen == 3 && !memcmp(type, "x11", 3)) {
5743 char *addrstr = smalloc(peeraddrlen+1);
5744 memcpy(addrstr, peeraddr, peeraddrlen);
5745 peeraddr[peeraddrlen] = '\0';
5746
5747 if (!ssh->X11_fwd_enabled)
5748 error = "X11 forwarding is not enabled";
5749 else if (x11_init(&c->u.x11.s, ssh->cfg.x11_display, c,
5750 ssh->x11auth, addrstr, port,
5751 &ssh->cfg) != NULL) {
5752 error = "Unable to open an X11 connection";
5753 } else {
5754 c->type = CHAN_X11;
5755 }
5756
5757 sfree(addrstr);
5758 } else if (typelen == 15 &&
5759 !memcmp(type, "forwarded-tcpip", 15)) {
5760 struct ssh_rportfwd pf, *realpf;
5761 char *dummy;
5762 int dummylen;
5763 ssh2_pkt_getstring(ssh, &dummy, &dummylen);/* skip address */
5764 pf.sport = ssh2_pkt_getuint32(ssh);
5765 realpf = find234(ssh->rportfwds, &pf, NULL);
5766 if (realpf == NULL) {
5767 error = "Remote port is not recognised";
5768 } else {
5769 char *e = pfd_newconnect(&c->u.pfd.s, realpf->dhost,
5770 realpf->dport, c, &ssh->cfg);
5771 logeventf(ssh, "Received remote port open request"
5772 " for %s:%d", realpf->dhost, realpf->dport);
5773 if (e != NULL) {
5774 logeventf(ssh, "Port open failed: %s", e);
5775 error = "Port open failed";
5776 } else {
5777 logevent("Forwarded port opened successfully");
5778 c->type = CHAN_SOCKDATA;
5779 }
5780 }
5781 } else if (typelen == 22 &&
5782 !memcmp(type, "auth-agent@openssh.com", 3)) {
5783 if (!ssh->agentfwd_enabled)
5784 error = "Agent forwarding is not enabled";
5785 else {
5786 c->type = CHAN_AGENT; /* identify channel type */
5787 c->u.a.lensofar = 0;
5788 }
5789 } else {
5790 error = "Unsupported channel type requested";
5791 }
5792
5793 c->remoteid = remid;
5794 if (error) {
5795 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN_FAILURE);
5796 ssh2_pkt_adduint32(ssh, c->remoteid);
5797 ssh2_pkt_adduint32(ssh, SSH2_OPEN_CONNECT_FAILED);
5798 ssh2_pkt_addstring(ssh, error);
5799 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5800 ssh2_pkt_send(ssh);
5801 sfree(c);
5802 } else {
5803 c->localid = alloc_channel_id(ssh);
5804 c->closes = 0;
5805 c->v.v2.locwindow = OUR_V2_WINSIZE;
5806 c->v.v2.remwindow = winsize;
5807 c->v.v2.remmaxpkt = pktsize;
5808 bufchain_init(&c->v.v2.outbuffer);
5809 add234(ssh->channels, c);
5810 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
5811 ssh2_pkt_adduint32(ssh, c->remoteid);
5812 ssh2_pkt_adduint32(ssh, c->localid);
5813 ssh2_pkt_adduint32(ssh, c->v.v2.locwindow);
5814 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
5815 ssh2_pkt_send(ssh);
5816 }
5817 } else {
5818 bombout((ssh,"Strange packet received: type %d", ssh->pktin.type));
5819 crReturnV;
5820 }
5821 } else {
5822 /*
5823 * We have spare data. Add it to the channel buffer.
5824 */
5825 ssh2_add_channel_data(ssh->mainchan, (char *)in, inlen);
5826 s->try_send = TRUE;
5827 }
5828 if (s->try_send) {
5829 int i;
5830 struct ssh_channel *c;
5831 /*
5832 * Try to send data on all channels if we can.
5833 */
5834 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
5835 int bufsize;
5836 if (c->closes)
5837 continue; /* don't send on closing channels */
5838 bufsize = ssh2_try_send(c);
5839 if (bufsize == 0) {
5840 switch (c->type) {
5841 case CHAN_MAINSESSION:
5842 /* stdin need not receive an unthrottle
5843 * notification since it will be polled */
5844 break;
5845 case CHAN_X11:
5846 x11_unthrottle(c->u.x11.s);
5847 break;
5848 case CHAN_AGENT:
5849 /* agent sockets are request/response and need no
5850 * buffer management */
5851 break;
5852 case CHAN_SOCKDATA:
5853 pfd_unthrottle(c->u.pfd.s);
5854 break;
5855 }
5856 }
5857 }
5858 }
5859 }
5860
5861 crFinishV;
5862 }
5863
5864 /*
5865 * Handle the top-level SSH2 protocol.
5866 */
5867 static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
5868 {
5869 if (do_ssh2_transport(ssh, in, inlen, ispkt) == 0)
5870 return;
5871 do_ssh2_authconn(ssh, in, inlen, ispkt);
5872 }
5873
5874 /*
5875 * Called to set up the connection.
5876 *
5877 * Returns an error message, or NULL on success.
5878 */
5879 static char *ssh_init(void *frontend_handle, void **backend_handle,
5880 Config *cfg,
5881 char *host, int port, char **realhost, int nodelay)
5882 {
5883 char *p;
5884 Ssh ssh;
5885
5886 ssh = smalloc(sizeof(*ssh));
5887 ssh->cfg = *cfg; /* STRUCTURE COPY */
5888 ssh->s = NULL;
5889 ssh->cipher = NULL;
5890 ssh->v1_cipher_ctx = NULL;
5891 ssh->crcda_ctx = NULL;
5892 ssh->cscipher = NULL;
5893 ssh->cs_cipher_ctx = NULL;
5894 ssh->sccipher = NULL;
5895 ssh->sc_cipher_ctx = NULL;
5896 ssh->csmac = NULL;
5897 ssh->cs_mac_ctx = NULL;
5898 ssh->scmac = NULL;
5899 ssh->sc_mac_ctx = NULL;
5900 ssh->cscomp = NULL;
5901 ssh->cs_comp_ctx = NULL;
5902 ssh->sccomp = NULL;
5903 ssh->sc_comp_ctx = NULL;
5904 ssh->kex = NULL;
5905 ssh->hostkey = NULL;
5906 ssh->exitcode = -1;
5907 ssh->state = SSH_STATE_PREPACKET;
5908 ssh->size_needed = FALSE;
5909 ssh->eof_needed = FALSE;
5910 ssh->ldisc = NULL;
5911 ssh->logctx = NULL;
5912 {
5913 static const struct Packet empty = { 0, 0, NULL, NULL, 0 };
5914 ssh->pktin = ssh->pktout = empty;
5915 }
5916 ssh->deferred_send_data = NULL;
5917 ssh->deferred_len = 0;
5918 ssh->deferred_size = 0;
5919 ssh->fallback_cmd = 0;
5920 ssh->pkt_ctx = 0;
5921 ssh->x11auth = NULL;
5922 ssh->v1_compressing = FALSE;
5923 ssh->v2_outgoing_sequence = 0;
5924 ssh->ssh1_rdpkt_crstate = 0;
5925 ssh->ssh2_rdpkt_crstate = 0;
5926 ssh->do_ssh_init_crstate = 0;
5927 ssh->ssh_gotdata_crstate = 0;
5928 ssh->ssh1_protocol_crstate = 0;
5929 ssh->do_ssh1_login_crstate = 0;
5930 ssh->do_ssh2_transport_crstate = 0;
5931 ssh->do_ssh2_authconn_crstate = 0;
5932 ssh->do_ssh_init_state = NULL;
5933 ssh->do_ssh1_login_state = NULL;
5934 ssh->do_ssh2_transport_state = NULL;
5935 ssh->do_ssh2_authconn_state = NULL;
5936 ssh->mainchan = NULL;
5937 ssh->throttled_all = 0;
5938 ssh->v1_stdout_throttling = 0;
5939
5940 *backend_handle = ssh;
5941
5942 #ifdef MSCRYPTOAPI
5943 if (crypto_startup() == 0)
5944 return "Microsoft high encryption pack not installed!";
5945 #endif
5946
5947 ssh->frontend = frontend_handle;
5948 ssh->term_width = ssh->cfg.width;
5949 ssh->term_height = ssh->cfg.height;
5950
5951 ssh->send_ok = 0;
5952 ssh->editing = 0;
5953 ssh->echoing = 0;
5954 ssh->v1_throttle_count = 0;
5955 ssh->overall_bufsize = 0;
5956 ssh->fallback_cmd = 0;
5957
5958 ssh->protocol = NULL;
5959
5960 p = connect_to_host(ssh, host, port, realhost, nodelay);
5961 if (p != NULL)
5962 return p;
5963
5964 return NULL;
5965 }
5966
5967 /*
5968 * Reconfigure the SSH backend.
5969 *
5970 * Currently, this function does nothing very useful. In future,
5971 * however, we could do some handy things with it. For example, we
5972 * could make the port forwarding configurer active in the Change
5973 * Settings box, and this routine could close down existing
5974 * forwardings and open up new ones in response to changes.
5975 */
5976 static void ssh_reconfig(void *handle, Config *cfg)
5977 {
5978 Ssh ssh = (Ssh) handle;
5979 ssh->cfg = *cfg; /* STRUCTURE COPY */
5980 }
5981
5982 /*
5983 * Called to send data down the Telnet connection.
5984 */
5985 static int ssh_send(void *handle, char *buf, int len)
5986 {
5987 Ssh ssh = (Ssh) handle;
5988
5989 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
5990 return 0;
5991
5992 ssh->protocol(ssh, (unsigned char *)buf, len, 0);
5993
5994 return ssh_sendbuffer(ssh);
5995 }
5996
5997 /*
5998 * Called to query the current amount of buffered stdin data.
5999 */
6000 static int ssh_sendbuffer(void *handle)
6001 {
6002 Ssh ssh = (Ssh) handle;
6003 int override_value;
6004
6005 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
6006 return 0;
6007
6008 /*
6009 * If the SSH socket itself has backed up, add the total backup
6010 * size on that to any individual buffer on the stdin channel.
6011 */
6012 override_value = 0;
6013 if (ssh->throttled_all)
6014 override_value = ssh->overall_bufsize;
6015
6016 if (ssh->version == 1) {
6017 return override_value;
6018 } else if (ssh->version == 2) {
6019 if (!ssh->mainchan || ssh->mainchan->closes > 0)
6020 return override_value;
6021 else
6022 return (override_value +
6023 bufchain_size(&ssh->mainchan->v.v2.outbuffer));
6024 }
6025
6026 return 0;
6027 }
6028
6029 /*
6030 * Called to set the size of the window from SSH's POV.
6031 */
6032 static void ssh_size(void *handle, int width, int height)
6033 {
6034 Ssh ssh = (Ssh) handle;
6035
6036 ssh->term_width = width;
6037 ssh->term_height = height;
6038
6039 switch (ssh->state) {
6040 case SSH_STATE_BEFORE_SIZE:
6041 case SSH_STATE_PREPACKET:
6042 case SSH_STATE_CLOSED:
6043 break; /* do nothing */
6044 case SSH_STATE_INTERMED:
6045 ssh->size_needed = TRUE; /* buffer for later */
6046 break;
6047 case SSH_STATE_SESSION:
6048 if (!ssh->cfg.nopty) {
6049 if (ssh->version == 1) {
6050 send_packet(ssh, SSH1_CMSG_WINDOW_SIZE,
6051 PKT_INT, ssh->term_height,
6052 PKT_INT, ssh->term_width,
6053 PKT_INT, 0, PKT_INT, 0, PKT_END);
6054 } else {
6055 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
6056 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
6057 ssh2_pkt_addstring(ssh, "window-change");
6058 ssh2_pkt_addbool(ssh, 0);
6059 ssh2_pkt_adduint32(ssh, ssh->term_width);
6060 ssh2_pkt_adduint32(ssh, ssh->term_height);
6061 ssh2_pkt_adduint32(ssh, 0);
6062 ssh2_pkt_adduint32(ssh, 0);
6063 ssh2_pkt_send(ssh);
6064 }
6065 }
6066 break;
6067 }
6068 }
6069
6070 /*
6071 * Send Telnet special codes. TS_EOF is useful for `plink', so you
6072 * can send an EOF and collect resulting output (e.g. `plink
6073 * hostname sort').
6074 */
6075 static void ssh_special(void *handle, Telnet_Special code)
6076 {
6077 Ssh ssh = (Ssh) handle;
6078
6079 if (code == TS_EOF) {
6080 if (ssh->state != SSH_STATE_SESSION) {
6081 /*
6082 * Buffer the EOF in case we are pre-SESSION, so we can
6083 * send it as soon as we reach SESSION.
6084 */
6085 if (code == TS_EOF)
6086 ssh->eof_needed = TRUE;
6087 return;
6088 }
6089 if (ssh->version == 1) {
6090 send_packet(ssh, SSH1_CMSG_EOF, PKT_END);
6091 } else {
6092 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_EOF);
6093 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
6094 ssh2_pkt_send(ssh);
6095 }
6096 logevent("Sent EOF message");
6097 } else if (code == TS_PING) {
6098 if (ssh->state == SSH_STATE_CLOSED
6099 || ssh->state == SSH_STATE_PREPACKET) return;
6100 if (ssh->version == 1) {
6101 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE))
6102 send_packet(ssh, SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
6103 } else {
6104 ssh2_pkt_init(ssh, SSH2_MSG_IGNORE);
6105 ssh2_pkt_addstring_start(ssh);
6106 ssh2_pkt_send(ssh);
6107 }
6108 } else {
6109 /* do nothing */
6110 }
6111 }
6112
6113 void *new_sock_channel(void *handle, Socket s)
6114 {
6115 Ssh ssh = (Ssh) handle;
6116 struct ssh_channel *c;
6117 c = smalloc(sizeof(struct ssh_channel));
6118 c->ssh = ssh;
6119
6120 if (c) {
6121 c->remoteid = -1; /* to be set when open confirmed */
6122 c->localid = alloc_channel_id(ssh);
6123 c->closes = 0;
6124 c->type = CHAN_SOCKDATA_DORMANT;/* identify channel type */
6125 c->u.pfd.s = s;
6126 bufchain_init(&c->v.v2.outbuffer);
6127 add234(ssh->channels, c);
6128 }
6129 return c;
6130 }
6131
6132 /*
6133 * This is called when stdout/stderr (the entity to which
6134 * from_backend sends data) manages to clear some backlog.
6135 */
6136 static void ssh_unthrottle(void *handle, int bufsize)
6137 {
6138 Ssh ssh = (Ssh) handle;
6139 if (ssh->version == 1) {
6140 if (ssh->v1_stdout_throttling && bufsize < SSH1_BUFFER_LIMIT) {
6141 ssh->v1_stdout_throttling = 0;
6142 ssh1_throttle(ssh, -1);
6143 }
6144 } else {
6145 if (ssh->mainchan && ssh->mainchan->closes == 0)
6146 ssh2_set_window(ssh->mainchan, OUR_V2_WINSIZE - bufsize);
6147 }
6148 }
6149
6150 void ssh_send_port_open(void *channel, char *hostname, int port, char *org)
6151 {
6152 struct ssh_channel *c = (struct ssh_channel *)channel;
6153 Ssh ssh = c->ssh;
6154
6155 logeventf(ssh, "Opening forwarded connection to %s:%d", hostname, port);
6156
6157 if (ssh->version == 1) {
6158 send_packet(ssh, SSH1_MSG_PORT_OPEN,
6159 PKT_INT, c->localid,
6160 PKT_STR, hostname,
6161 PKT_INT, port,
6162 //PKT_STR, <org:orgport>,
6163 PKT_END);
6164 } else {
6165 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN);
6166 ssh2_pkt_addstring(ssh, "direct-tcpip");
6167 ssh2_pkt_adduint32(ssh, c->localid);
6168 c->v.v2.locwindow = OUR_V2_WINSIZE;
6169 ssh2_pkt_adduint32(ssh, c->v.v2.locwindow);/* our window size */
6170 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
6171 ssh2_pkt_addstring(ssh, hostname);
6172 ssh2_pkt_adduint32(ssh, port);
6173 /*
6174 * We make up values for the originator data; partly it's
6175 * too much hassle to keep track, and partly I'm not
6176 * convinced the server should be told details like that
6177 * about my local network configuration.
6178 */
6179 ssh2_pkt_addstring(ssh, "client-side-connection");
6180 ssh2_pkt_adduint32(ssh, 0);
6181 ssh2_pkt_send(ssh);
6182 }
6183 }
6184
6185
6186 static Socket ssh_socket(void *handle)
6187 {
6188 Ssh ssh = (Ssh) handle;
6189 return ssh->s;
6190 }
6191
6192 static int ssh_sendok(void *handle)
6193 {
6194 Ssh ssh = (Ssh) handle;
6195 return ssh->send_ok;
6196 }
6197
6198 static int ssh_ldisc(void *handle, int option)
6199 {
6200 Ssh ssh = (Ssh) handle;
6201 if (option == LD_ECHO)
6202 return ssh->echoing;
6203 if (option == LD_EDIT)
6204 return ssh->editing;
6205 return FALSE;
6206 }
6207
6208 static void ssh_provide_ldisc(void *handle, void *ldisc)
6209 {
6210 Ssh ssh = (Ssh) handle;
6211 ssh->ldisc = ldisc;
6212 }
6213
6214 static void ssh_provide_logctx(void *handle, void *logctx)
6215 {
6216 Ssh ssh = (Ssh) handle;
6217 ssh->logctx = logctx;
6218 }
6219
6220 static int ssh_return_exitcode(void *handle)
6221 {
6222 Ssh ssh = (Ssh) handle;
6223 return ssh->exitcode;
6224 }
6225
6226 /*
6227 * Gross hack: pscp will try to start SFTP but fall back to scp1 if
6228 * that fails. This variable is the means by which scp.c can reach
6229 * into the SSH code and find out which one it got.
6230 */
6231 extern int ssh_fallback_cmd(void *handle)
6232 {
6233 Ssh ssh = (Ssh) handle;
6234 return ssh->fallback_cmd;
6235 }
6236
6237 Backend ssh_backend = {
6238 ssh_init,
6239 ssh_reconfig,
6240 ssh_send,
6241 ssh_sendbuffer,
6242 ssh_size,
6243 ssh_special,
6244 ssh_socket,
6245 ssh_return_exitcode,
6246 ssh_sendok,
6247 ssh_ldisc,
6248 ssh_provide_ldisc,
6249 ssh_provide_logctx,
6250 ssh_unthrottle,
6251 22
6252 };
Local modifications for Simon Tatham's `PuTTY' SSH client and terminal emulator