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I think the Carbon build now works well enough to be worth turning on by
[u/mdw/putty] / ssh.c
1 #include <stdio.h>
2 #include <stdlib.h>
3 #include <stdarg.h>
4 #include <assert.h>
5
6 #include "putty.h"
7 #include "tree234.h"
8 #include "ssh.h"
9
10 #ifndef FALSE
11 #define FALSE 0
12 #endif
13 #ifndef TRUE
14 #define TRUE 1
15 #endif
16
17 #define SSH1_MSG_DISCONNECT 1 /* 0x1 */
18 #define SSH1_SMSG_PUBLIC_KEY 2 /* 0x2 */
19 #define SSH1_CMSG_SESSION_KEY 3 /* 0x3 */
20 #define SSH1_CMSG_USER 4 /* 0x4 */
21 #define SSH1_CMSG_AUTH_RSA 6 /* 0x6 */
22 #define SSH1_SMSG_AUTH_RSA_CHALLENGE 7 /* 0x7 */
23 #define SSH1_CMSG_AUTH_RSA_RESPONSE 8 /* 0x8 */
24 #define SSH1_CMSG_AUTH_PASSWORD 9 /* 0x9 */
25 #define SSH1_CMSG_REQUEST_PTY 10 /* 0xa */
26 #define SSH1_CMSG_WINDOW_SIZE 11 /* 0xb */
27 #define SSH1_CMSG_EXEC_SHELL 12 /* 0xc */
28 #define SSH1_CMSG_EXEC_CMD 13 /* 0xd */
29 #define SSH1_SMSG_SUCCESS 14 /* 0xe */
30 #define SSH1_SMSG_FAILURE 15 /* 0xf */
31 #define SSH1_CMSG_STDIN_DATA 16 /* 0x10 */
32 #define SSH1_SMSG_STDOUT_DATA 17 /* 0x11 */
33 #define SSH1_SMSG_STDERR_DATA 18 /* 0x12 */
34 #define SSH1_CMSG_EOF 19 /* 0x13 */
35 #define SSH1_SMSG_EXIT_STATUS 20 /* 0x14 */
36 #define SSH1_MSG_CHANNEL_OPEN_CONFIRMATION 21 /* 0x15 */
37 #define SSH1_MSG_CHANNEL_OPEN_FAILURE 22 /* 0x16 */
38 #define SSH1_MSG_CHANNEL_DATA 23 /* 0x17 */
39 #define SSH1_MSG_CHANNEL_CLOSE 24 /* 0x18 */
40 #define SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION 25 /* 0x19 */
41 #define SSH1_SMSG_X11_OPEN 27 /* 0x1b */
42 #define SSH1_CMSG_PORT_FORWARD_REQUEST 28 /* 0x1c */
43 #define SSH1_MSG_PORT_OPEN 29 /* 0x1d */
44 #define SSH1_CMSG_AGENT_REQUEST_FORWARDING 30 /* 0x1e */
45 #define SSH1_SMSG_AGENT_OPEN 31 /* 0x1f */
46 #define SSH1_MSG_IGNORE 32 /* 0x20 */
47 #define SSH1_CMSG_EXIT_CONFIRMATION 33 /* 0x21 */
48 #define SSH1_CMSG_X11_REQUEST_FORWARDING 34 /* 0x22 */
49 #define SSH1_CMSG_AUTH_RHOSTS_RSA 35 /* 0x23 */
50 #define SSH1_MSG_DEBUG 36 /* 0x24 */
51 #define SSH1_CMSG_REQUEST_COMPRESSION 37 /* 0x25 */
52 #define SSH1_CMSG_AUTH_TIS 39 /* 0x27 */
53 #define SSH1_SMSG_AUTH_TIS_CHALLENGE 40 /* 0x28 */
54 #define SSH1_CMSG_AUTH_TIS_RESPONSE 41 /* 0x29 */
55 #define SSH1_CMSG_AUTH_CCARD 70 /* 0x46 */
56 #define SSH1_SMSG_AUTH_CCARD_CHALLENGE 71 /* 0x47 */
57 #define SSH1_CMSG_AUTH_CCARD_RESPONSE 72 /* 0x48 */
58
59 #define SSH1_AUTH_TIS 5 /* 0x5 */
60 #define SSH1_AUTH_CCARD 16 /* 0x10 */
61
62 #define SSH1_PROTOFLAG_SCREEN_NUMBER 1 /* 0x1 */
63 /* Mask for protoflags we will echo back to server if seen */
64 #define SSH1_PROTOFLAGS_SUPPORTED 0 /* 0x1 */
65
66 #define SSH2_MSG_DISCONNECT 1 /* 0x1 */
67 #define SSH2_MSG_IGNORE 2 /* 0x2 */
68 #define SSH2_MSG_UNIMPLEMENTED 3 /* 0x3 */
69 #define SSH2_MSG_DEBUG 4 /* 0x4 */
70 #define SSH2_MSG_SERVICE_REQUEST 5 /* 0x5 */
71 #define SSH2_MSG_SERVICE_ACCEPT 6 /* 0x6 */
72 #define SSH2_MSG_KEXINIT 20 /* 0x14 */
73 #define SSH2_MSG_NEWKEYS 21 /* 0x15 */
74 #define SSH2_MSG_KEXDH_INIT 30 /* 0x1e */
75 #define SSH2_MSG_KEXDH_REPLY 31 /* 0x1f */
76 #define SSH2_MSG_KEX_DH_GEX_REQUEST 30 /* 0x1e */
77 #define SSH2_MSG_KEX_DH_GEX_GROUP 31 /* 0x1f */
78 #define SSH2_MSG_KEX_DH_GEX_INIT 32 /* 0x20 */
79 #define SSH2_MSG_KEX_DH_GEX_REPLY 33 /* 0x21 */
80 #define SSH2_MSG_USERAUTH_REQUEST 50 /* 0x32 */
81 #define SSH2_MSG_USERAUTH_FAILURE 51 /* 0x33 */
82 #define SSH2_MSG_USERAUTH_SUCCESS 52 /* 0x34 */
83 #define SSH2_MSG_USERAUTH_BANNER 53 /* 0x35 */
84 #define SSH2_MSG_USERAUTH_PK_OK 60 /* 0x3c */
85 #define SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ 60 /* 0x3c */
86 #define SSH2_MSG_USERAUTH_INFO_REQUEST 60 /* 0x3c */
87 #define SSH2_MSG_USERAUTH_INFO_RESPONSE 61 /* 0x3d */
88 #define SSH2_MSG_GLOBAL_REQUEST 80 /* 0x50 */
89 #define SSH2_MSG_REQUEST_SUCCESS 81 /* 0x51 */
90 #define SSH2_MSG_REQUEST_FAILURE 82 /* 0x52 */
91 #define SSH2_MSG_CHANNEL_OPEN 90 /* 0x5a */
92 #define SSH2_MSG_CHANNEL_OPEN_CONFIRMATION 91 /* 0x5b */
93 #define SSH2_MSG_CHANNEL_OPEN_FAILURE 92 /* 0x5c */
94 #define SSH2_MSG_CHANNEL_WINDOW_ADJUST 93 /* 0x5d */
95 #define SSH2_MSG_CHANNEL_DATA 94 /* 0x5e */
96 #define SSH2_MSG_CHANNEL_EXTENDED_DATA 95 /* 0x5f */
97 #define SSH2_MSG_CHANNEL_EOF 96 /* 0x60 */
98 #define SSH2_MSG_CHANNEL_CLOSE 97 /* 0x61 */
99 #define SSH2_MSG_CHANNEL_REQUEST 98 /* 0x62 */
100 #define SSH2_MSG_CHANNEL_SUCCESS 99 /* 0x63 */
101 #define SSH2_MSG_CHANNEL_FAILURE 100 /* 0x64 */
102
103 /*
104 * Packet type contexts, so that ssh2_pkt_type can correctly decode
105 * the ambiguous type numbers back into the correct type strings.
106 */
107 #define SSH2_PKTCTX_DHGROUP1 0x0001
108 #define SSH2_PKTCTX_DHGEX 0x0002
109 #define SSH2_PKTCTX_PUBLICKEY 0x0010
110 #define SSH2_PKTCTX_PASSWORD 0x0020
111 #define SSH2_PKTCTX_KBDINTER 0x0040
112 #define SSH2_PKTCTX_AUTH_MASK 0x00F0
113
114 #define SSH2_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT 1 /* 0x1 */
115 #define SSH2_DISCONNECT_PROTOCOL_ERROR 2 /* 0x2 */
116 #define SSH2_DISCONNECT_KEY_EXCHANGE_FAILED 3 /* 0x3 */
117 #define SSH2_DISCONNECT_HOST_AUTHENTICATION_FAILED 4 /* 0x4 */
118 #define SSH2_DISCONNECT_MAC_ERROR 5 /* 0x5 */
119 #define SSH2_DISCONNECT_COMPRESSION_ERROR 6 /* 0x6 */
120 #define SSH2_DISCONNECT_SERVICE_NOT_AVAILABLE 7 /* 0x7 */
121 #define SSH2_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED 8 /* 0x8 */
122 #define SSH2_DISCONNECT_HOST_KEY_NOT_VERIFIABLE 9 /* 0x9 */
123 #define SSH2_DISCONNECT_CONNECTION_LOST 10 /* 0xa */
124 #define SSH2_DISCONNECT_BY_APPLICATION 11 /* 0xb */
125 #define SSH2_DISCONNECT_TOO_MANY_CONNECTIONS 12 /* 0xc */
126 #define SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER 13 /* 0xd */
127 #define SSH2_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE 14 /* 0xe */
128 #define SSH2_DISCONNECT_ILLEGAL_USER_NAME 15 /* 0xf */
129
130 static const char *const ssh2_disconnect_reasons[] = {
131 NULL,
132 "SSH_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT",
133 "SSH_DISCONNECT_PROTOCOL_ERROR",
134 "SSH_DISCONNECT_KEY_EXCHANGE_FAILED",
135 "SSH_DISCONNECT_HOST_AUTHENTICATION_FAILED",
136 "SSH_DISCONNECT_MAC_ERROR",
137 "SSH_DISCONNECT_COMPRESSION_ERROR",
138 "SSH_DISCONNECT_SERVICE_NOT_AVAILABLE",
139 "SSH_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED",
140 "SSH_DISCONNECT_HOST_KEY_NOT_VERIFIABLE",
141 "SSH_DISCONNECT_CONNECTION_LOST",
142 "SSH_DISCONNECT_BY_APPLICATION",
143 "SSH_DISCONNECT_TOO_MANY_CONNECTIONS",
144 "SSH_DISCONNECT_AUTH_CANCELLED_BY_USER",
145 "SSH_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE",
146 "SSH_DISCONNECT_ILLEGAL_USER_NAME",
147 };
148
149 #define SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED 1 /* 0x1 */
150 #define SSH2_OPEN_CONNECT_FAILED 2 /* 0x2 */
151 #define SSH2_OPEN_UNKNOWN_CHANNEL_TYPE 3 /* 0x3 */
152 #define SSH2_OPEN_RESOURCE_SHORTAGE 4 /* 0x4 */
153
154 #define SSH2_EXTENDED_DATA_STDERR 1 /* 0x1 */
155
156 /*
157 * Various remote-bug flags.
158 */
159 #define BUG_CHOKES_ON_SSH1_IGNORE 1
160 #define BUG_SSH2_HMAC 2
161 #define BUG_NEEDS_SSH1_PLAIN_PASSWORD 4
162 #define BUG_CHOKES_ON_RSA 8
163 #define BUG_SSH2_RSA_PADDING 16
164 #define BUG_SSH2_DERIVEKEY 32
165 #define BUG_SSH2_DH_GEX 64
166 #define BUG_SSH2_PK_SESSIONID 128
167
168 #define translate(x) if (type == x) return #x
169 #define translatec(x,ctx) if (type == x && (pkt_ctx & ctx)) return #x
170 static char *ssh1_pkt_type(int type)
171 {
172 translate(SSH1_MSG_DISCONNECT);
173 translate(SSH1_SMSG_PUBLIC_KEY);
174 translate(SSH1_CMSG_SESSION_KEY);
175 translate(SSH1_CMSG_USER);
176 translate(SSH1_CMSG_AUTH_RSA);
177 translate(SSH1_SMSG_AUTH_RSA_CHALLENGE);
178 translate(SSH1_CMSG_AUTH_RSA_RESPONSE);
179 translate(SSH1_CMSG_AUTH_PASSWORD);
180 translate(SSH1_CMSG_REQUEST_PTY);
181 translate(SSH1_CMSG_WINDOW_SIZE);
182 translate(SSH1_CMSG_EXEC_SHELL);
183 translate(SSH1_CMSG_EXEC_CMD);
184 translate(SSH1_SMSG_SUCCESS);
185 translate(SSH1_SMSG_FAILURE);
186 translate(SSH1_CMSG_STDIN_DATA);
187 translate(SSH1_SMSG_STDOUT_DATA);
188 translate(SSH1_SMSG_STDERR_DATA);
189 translate(SSH1_CMSG_EOF);
190 translate(SSH1_SMSG_EXIT_STATUS);
191 translate(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION);
192 translate(SSH1_MSG_CHANNEL_OPEN_FAILURE);
193 translate(SSH1_MSG_CHANNEL_DATA);
194 translate(SSH1_MSG_CHANNEL_CLOSE);
195 translate(SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION);
196 translate(SSH1_SMSG_X11_OPEN);
197 translate(SSH1_CMSG_PORT_FORWARD_REQUEST);
198 translate(SSH1_MSG_PORT_OPEN);
199 translate(SSH1_CMSG_AGENT_REQUEST_FORWARDING);
200 translate(SSH1_SMSG_AGENT_OPEN);
201 translate(SSH1_MSG_IGNORE);
202 translate(SSH1_CMSG_EXIT_CONFIRMATION);
203 translate(SSH1_CMSG_X11_REQUEST_FORWARDING);
204 translate(SSH1_CMSG_AUTH_RHOSTS_RSA);
205 translate(SSH1_MSG_DEBUG);
206 translate(SSH1_CMSG_REQUEST_COMPRESSION);
207 translate(SSH1_CMSG_AUTH_TIS);
208 translate(SSH1_SMSG_AUTH_TIS_CHALLENGE);
209 translate(SSH1_CMSG_AUTH_TIS_RESPONSE);
210 translate(SSH1_CMSG_AUTH_CCARD);
211 translate(SSH1_SMSG_AUTH_CCARD_CHALLENGE);
212 translate(SSH1_CMSG_AUTH_CCARD_RESPONSE);
213 return "unknown";
214 }
215 static char *ssh2_pkt_type(int pkt_ctx, int type)
216 {
217 translate(SSH2_MSG_DISCONNECT);
218 translate(SSH2_MSG_IGNORE);
219 translate(SSH2_MSG_UNIMPLEMENTED);
220 translate(SSH2_MSG_DEBUG);
221 translate(SSH2_MSG_SERVICE_REQUEST);
222 translate(SSH2_MSG_SERVICE_ACCEPT);
223 translate(SSH2_MSG_KEXINIT);
224 translate(SSH2_MSG_NEWKEYS);
225 translatec(SSH2_MSG_KEXDH_INIT, SSH2_PKTCTX_DHGROUP1);
226 translatec(SSH2_MSG_KEXDH_REPLY, SSH2_PKTCTX_DHGROUP1);
227 translatec(SSH2_MSG_KEX_DH_GEX_REQUEST, SSH2_PKTCTX_DHGEX);
228 translatec(SSH2_MSG_KEX_DH_GEX_GROUP, SSH2_PKTCTX_DHGEX);
229 translatec(SSH2_MSG_KEX_DH_GEX_INIT, SSH2_PKTCTX_DHGEX);
230 translatec(SSH2_MSG_KEX_DH_GEX_REPLY, SSH2_PKTCTX_DHGEX);
231 translate(SSH2_MSG_USERAUTH_REQUEST);
232 translate(SSH2_MSG_USERAUTH_FAILURE);
233 translate(SSH2_MSG_USERAUTH_SUCCESS);
234 translate(SSH2_MSG_USERAUTH_BANNER);
235 translatec(SSH2_MSG_USERAUTH_PK_OK, SSH2_PKTCTX_PUBLICKEY);
236 translatec(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, SSH2_PKTCTX_PASSWORD);
237 translatec(SSH2_MSG_USERAUTH_INFO_REQUEST, SSH2_PKTCTX_KBDINTER);
238 translatec(SSH2_MSG_USERAUTH_INFO_RESPONSE, SSH2_PKTCTX_KBDINTER);
239 translate(SSH2_MSG_GLOBAL_REQUEST);
240 translate(SSH2_MSG_REQUEST_SUCCESS);
241 translate(SSH2_MSG_REQUEST_FAILURE);
242 translate(SSH2_MSG_CHANNEL_OPEN);
243 translate(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
244 translate(SSH2_MSG_CHANNEL_OPEN_FAILURE);
245 translate(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
246 translate(SSH2_MSG_CHANNEL_DATA);
247 translate(SSH2_MSG_CHANNEL_EXTENDED_DATA);
248 translate(SSH2_MSG_CHANNEL_EOF);
249 translate(SSH2_MSG_CHANNEL_CLOSE);
250 translate(SSH2_MSG_CHANNEL_REQUEST);
251 translate(SSH2_MSG_CHANNEL_SUCCESS);
252 translate(SSH2_MSG_CHANNEL_FAILURE);
253 return "unknown";
254 }
255 #undef translate
256 #undef translatec
257
258 #define GET_32BIT(cp) \
259 (((unsigned long)(unsigned char)(cp)[0] << 24) | \
260 ((unsigned long)(unsigned char)(cp)[1] << 16) | \
261 ((unsigned long)(unsigned char)(cp)[2] << 8) | \
262 ((unsigned long)(unsigned char)(cp)[3]))
263
264 #define PUT_32BIT(cp, value) { \
265 (cp)[0] = (unsigned char)((value) >> 24); \
266 (cp)[1] = (unsigned char)((value) >> 16); \
267 (cp)[2] = (unsigned char)((value) >> 8); \
268 (cp)[3] = (unsigned char)(value); }
269
270 enum { PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR, PKT_BIGNUM };
271
272 /* Coroutine mechanics for the sillier bits of the code */
273 #define crBegin(v) { int *crLine = &v; switch(v) { case 0:;
274 #define crState(t) \
275 struct t *s; \
276 if (!ssh->t) ssh->t = smalloc(sizeof(struct t)); \
277 s = ssh->t;
278 #define crFinish(z) } *crLine = 0; return (z); }
279 #define crFinishV } *crLine = 0; return; }
280 #define crReturn(z) \
281 do {\
282 *crLine =__LINE__; return (z); case __LINE__:;\
283 } while (0)
284 #define crReturnV \
285 do {\
286 *crLine=__LINE__; return; case __LINE__:;\
287 } while (0)
288 #define crStop(z) do{ *crLine = 0; return (z); }while(0)
289 #define crStopV do{ *crLine = 0; return; }while(0)
290 #define crWaitUntil(c) do { crReturn(0); } while (!(c))
291 #define crWaitUntilV(c) do { crReturnV; } while (!(c))
292
293 typedef struct ssh_tag *Ssh;
294
295 static void ssh2_pkt_init(Ssh, int pkt_type);
296 static void ssh2_pkt_addbool(Ssh, unsigned char value);
297 static void ssh2_pkt_adduint32(Ssh, unsigned long value);
298 static void ssh2_pkt_addstring_start(Ssh);
299 static void ssh2_pkt_addstring_str(Ssh, char *data);
300 static void ssh2_pkt_addstring_data(Ssh, char *data, int len);
301 static void ssh2_pkt_addstring(Ssh, char *data);
302 static unsigned char *ssh2_mpint_fmt(Bignum b, int *len);
303 static void ssh2_pkt_addmp(Ssh, Bignum b);
304 static int ssh2_pkt_construct(Ssh);
305 static void ssh2_pkt_send(Ssh);
306
307 /*
308 * Buffer management constants. There are several of these for
309 * various different purposes:
310 *
311 * - SSH1_BUFFER_LIMIT is the amount of backlog that must build up
312 * on a local data stream before we throttle the whole SSH
313 * connection (in SSH1 only). Throttling the whole connection is
314 * pretty drastic so we set this high in the hope it won't
315 * happen very often.
316 *
317 * - SSH_MAX_BACKLOG is the amount of backlog that must build up
318 * on the SSH connection itself before we defensively throttle
319 * _all_ local data streams. This is pretty drastic too (though
320 * thankfully unlikely in SSH2 since the window mechanism should
321 * ensure that the server never has any need to throttle its end
322 * of the connection), so we set this high as well.
323 *
324 * - OUR_V2_WINSIZE is the maximum window size we present on SSH2
325 * channels.
326 */
327
328 #define SSH1_BUFFER_LIMIT 32768
329 #define SSH_MAX_BACKLOG 32768
330 #define OUR_V2_WINSIZE 16384
331
332 const static struct ssh_kex *kex_algs[] = {
333 &ssh_diffiehellman_gex,
334 &ssh_diffiehellman
335 };
336
337 const static struct ssh_signkey *hostkey_algs[] = { &ssh_rsa, &ssh_dss };
338
339 static void *nullmac_make_context(void)
340 {
341 return NULL;
342 }
343 static void nullmac_free_context(void *handle)
344 {
345 }
346 static void nullmac_key(void *handle, unsigned char *key)
347 {
348 }
349 static void nullmac_generate(void *handle, unsigned char *blk, int len,
350 unsigned long seq)
351 {
352 }
353 static int nullmac_verify(void *handle, unsigned char *blk, int len,
354 unsigned long seq)
355 {
356 return 1;
357 }
358 const static struct ssh_mac ssh_mac_none = {
359 nullmac_make_context, nullmac_free_context, nullmac_key,
360 nullmac_generate, nullmac_verify, "none", 0
361 };
362 const static struct ssh_mac *macs[] = {
363 &ssh_sha1, &ssh_md5, &ssh_mac_none
364 };
365 const static struct ssh_mac *buggymacs[] = {
366 &ssh_sha1_buggy, &ssh_md5, &ssh_mac_none
367 };
368
369 static void *ssh_comp_none_init(void)
370 {
371 return NULL;
372 }
373 static void ssh_comp_none_cleanup(void *handle)
374 {
375 }
376 static int ssh_comp_none_block(void *handle, unsigned char *block, int len,
377 unsigned char **outblock, int *outlen)
378 {
379 return 0;
380 }
381 static int ssh_comp_none_disable(void *handle)
382 {
383 return 0;
384 }
385 const static struct ssh_compress ssh_comp_none = {
386 "none",
387 ssh_comp_none_init, ssh_comp_none_cleanup, ssh_comp_none_block,
388 ssh_comp_none_init, ssh_comp_none_cleanup, ssh_comp_none_block,
389 ssh_comp_none_disable, NULL
390 };
391 extern const struct ssh_compress ssh_zlib;
392 const static struct ssh_compress *compressions[] = {
393 &ssh_zlib, &ssh_comp_none
394 };
395
396 enum { /* channel types */
397 CHAN_MAINSESSION,
398 CHAN_X11,
399 CHAN_AGENT,
400 CHAN_SOCKDATA,
401 CHAN_SOCKDATA_DORMANT /* one the remote hasn't confirmed */
402 };
403
404 /*
405 * 2-3-4 tree storing channels.
406 */
407 struct ssh_channel {
408 Ssh ssh; /* pointer back to main context */
409 unsigned remoteid, localid;
410 int type;
411 /*
412 * In SSH1, this value contains four bits:
413 *
414 * 1 We have sent SSH1_MSG_CHANNEL_CLOSE.
415 * 2 We have sent SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION.
416 * 4 We have received SSH1_MSG_CHANNEL_CLOSE.
417 * 8 We have received SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION.
418 *
419 * A channel is completely finished with when all four bits are set.
420 */
421 int closes;
422 union {
423 struct ssh1_data_channel {
424 int throttling;
425 } v1;
426 struct ssh2_data_channel {
427 bufchain outbuffer;
428 unsigned remwindow, remmaxpkt;
429 unsigned locwindow;
430 } v2;
431 } v;
432 union {
433 struct ssh_agent_channel {
434 unsigned char *message;
435 unsigned char msglen[4];
436 int lensofar, totallen;
437 } a;
438 struct ssh_x11_channel {
439 Socket s;
440 } x11;
441 struct ssh_pfd_channel {
442 Socket s;
443 } pfd;
444 } u;
445 };
446
447 /*
448 * 2-3-4 tree storing remote->local port forwardings. SSH 1 and SSH
449 * 2 use this structure in different ways, reflecting SSH 2's
450 * altogether saner approach to port forwarding.
451 *
452 * In SSH 1, you arrange a remote forwarding by sending the server
453 * the remote port number, and the local destination host:port.
454 * When a connection comes in, the server sends you back that
455 * host:port pair, and you connect to it. This is a ready-made
456 * security hole if you're not on the ball: a malicious server
457 * could send you back _any_ host:port pair, so if you trustingly
458 * connect to the address it gives you then you've just opened the
459 * entire inside of your corporate network just by connecting
460 * through it to a dodgy SSH server. Hence, we must store a list of
461 * host:port pairs we _are_ trying to forward to, and reject a
462 * connection request from the server if it's not in the list.
463 *
464 * In SSH 2, each side of the connection minds its own business and
465 * doesn't send unnecessary information to the other. You arrange a
466 * remote forwarding by sending the server just the remote port
467 * number. When a connection comes in, the server tells you which
468 * of its ports was connected to; and _you_ have to remember what
469 * local host:port pair went with that port number.
470 *
471 * Hence: in SSH 1 this structure stores host:port pairs we intend
472 * to allow connections to, and is indexed by those host:port
473 * pairs. In SSH 2 it stores a mapping from source port to
474 * destination host:port pair, and is indexed by source port.
475 */
476 struct ssh_rportfwd {
477 unsigned sport, dport;
478 char dhost[256];
479 };
480
481 struct Packet {
482 long length;
483 int type;
484 unsigned char *data;
485 unsigned char *body;
486 long savedpos;
487 long maxlen;
488 };
489
490 static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt);
491 static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt);
492 static void ssh_size(void *handle, int width, int height);
493 static void ssh_special(void *handle, Telnet_Special);
494 static int ssh2_try_send(struct ssh_channel *c);
495 static void ssh2_add_channel_data(struct ssh_channel *c, char *buf, int len);
496 static void ssh_throttle_all(Ssh ssh, int enable, int bufsize);
497 static void ssh2_set_window(struct ssh_channel *c, unsigned newwin);
498 static int ssh_sendbuffer(void *handle);
499
500 struct rdpkt1_state_tag {
501 long len, pad, biglen, to_read;
502 unsigned long realcrc, gotcrc;
503 unsigned char *p;
504 int i;
505 int chunk;
506 };
507
508 struct rdpkt2_state_tag {
509 long len, pad, payload, packetlen, maclen;
510 int i;
511 int cipherblk;
512 unsigned long incoming_sequence;
513 };
514
515 struct ssh_tag {
516 const struct plug_function_table *fn;
517 /* the above field _must_ be first in the structure */
518
519 SHA_State exhash, exhashbase;
520
521 Socket s;
522
523 void *ldisc;
524 void *logctx;
525
526 unsigned char session_key[32];
527 int v1_compressing;
528 int v1_remote_protoflags;
529 int v1_local_protoflags;
530 int agentfwd_enabled;
531 int X11_fwd_enabled;
532 int remote_bugs;
533 const struct ssh_cipher *cipher;
534 void *v1_cipher_ctx;
535 void *crcda_ctx;
536 const struct ssh2_cipher *cscipher, *sccipher;
537 void *cs_cipher_ctx, *sc_cipher_ctx;
538 const struct ssh_mac *csmac, *scmac;
539 void *cs_mac_ctx, *sc_mac_ctx;
540 const struct ssh_compress *cscomp, *sccomp;
541 void *cs_comp_ctx, *sc_comp_ctx;
542 const struct ssh_kex *kex;
543 const struct ssh_signkey *hostkey;
544 unsigned char v2_session_id[20];
545 void *kex_ctx;
546
547 char *savedhost;
548 int savedport;
549 int send_ok;
550 int echoing, editing;
551
552 void *frontend;
553
554 int term_width, term_height;
555
556 tree234 *channels; /* indexed by local id */
557 struct ssh_channel *mainchan; /* primary session channel */
558 int exitcode;
559
560 tree234 *rportfwds;
561
562 enum {
563 SSH_STATE_PREPACKET,
564 SSH_STATE_BEFORE_SIZE,
565 SSH_STATE_INTERMED,
566 SSH_STATE_SESSION,
567 SSH_STATE_CLOSED
568 } state;
569
570 int size_needed, eof_needed;
571
572 struct Packet pktin;
573 struct Packet pktout;
574 unsigned char *deferred_send_data;
575 int deferred_len, deferred_size;
576
577 /*
578 * Gross hack: pscp will try to start SFTP but fall back to
579 * scp1 if that fails. This variable is the means by which
580 * scp.c can reach into the SSH code and find out which one it
581 * got.
582 */
583 int fallback_cmd;
584
585 /*
586 * Used for username and password input.
587 */
588 char *userpass_input_buffer;
589 int userpass_input_buflen;
590 int userpass_input_bufpos;
591 int userpass_input_echo;
592
593 char *portfwd_strptr;
594 int pkt_ctx;
595
596 void *x11auth;
597
598 int version;
599 int v1_throttle_count;
600 int overall_bufsize;
601 int throttled_all;
602 int v1_stdout_throttling;
603 int v2_outgoing_sequence;
604
605 int ssh1_rdpkt_crstate;
606 int ssh2_rdpkt_crstate;
607 int do_ssh_init_crstate;
608 int ssh_gotdata_crstate;
609 int ssh1_protocol_crstate;
610 int do_ssh1_login_crstate;
611 int do_ssh2_transport_crstate;
612 int do_ssh2_authconn_crstate;
613
614 void *do_ssh_init_state;
615 void *do_ssh1_login_state;
616 void *do_ssh2_transport_state;
617 void *do_ssh2_authconn_state;
618
619 struct rdpkt1_state_tag rdpkt1_state;
620 struct rdpkt2_state_tag rdpkt2_state;
621
622 void (*protocol) (Ssh ssh, unsigned char *in, int inlen, int ispkt);
623 int (*s_rdpkt) (Ssh ssh, unsigned char **data, int *datalen);
624
625 /*
626 * We maintain a full _copy_ of a Config structure here, not
627 * merely a pointer to it. That way, when we're passed a new
628 * one for reconfiguration, we can check the differences and
629 * potentially reconfigure port forwardings etc in mid-session.
630 */
631 Config cfg;
632 };
633
634 #define logevent(s) logevent(ssh->frontend, s)
635
636 /* logevent, only printf-formatted. */
637 static void logeventf(Ssh ssh, char *fmt, ...)
638 {
639 va_list ap;
640 char *buf;
641
642 va_start(ap, fmt);
643 buf = dupvprintf(fmt, ap);
644 va_end(ap);
645 logevent(buf);
646 sfree(buf);
647 }
648
649 #define bombout(msg) ( ssh->state = SSH_STATE_CLOSED, \
650 (ssh->s ? sk_close(ssh->s), ssh->s = NULL : 0), \
651 logeventf msg, connection_fatal msg )
652
653 static int ssh_channelcmp(void *av, void *bv)
654 {
655 struct ssh_channel *a = (struct ssh_channel *) av;
656 struct ssh_channel *b = (struct ssh_channel *) bv;
657 if (a->localid < b->localid)
658 return -1;
659 if (a->localid > b->localid)
660 return +1;
661 return 0;
662 }
663 static int ssh_channelfind(void *av, void *bv)
664 {
665 unsigned *a = (unsigned *) av;
666 struct ssh_channel *b = (struct ssh_channel *) bv;
667 if (*a < b->localid)
668 return -1;
669 if (*a > b->localid)
670 return +1;
671 return 0;
672 }
673
674 static int ssh_rportcmp_ssh1(void *av, void *bv)
675 {
676 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
677 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
678 int i;
679 if ( (i = strcmp(a->dhost, b->dhost)) != 0)
680 return i < 0 ? -1 : +1;
681 if (a->dport > b->dport)
682 return +1;
683 if (a->dport < b->dport)
684 return -1;
685 return 0;
686 }
687
688 static int ssh_rportcmp_ssh2(void *av, void *bv)
689 {
690 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
691 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
692
693 if (a->sport > b->sport)
694 return +1;
695 if (a->sport < b->sport)
696 return -1;
697 return 0;
698 }
699
700 static int alloc_channel_id(Ssh ssh)
701 {
702 const unsigned CHANNEL_NUMBER_OFFSET = 256;
703 unsigned low, high, mid;
704 int tsize;
705 struct ssh_channel *c;
706
707 /*
708 * First-fit allocation of channel numbers: always pick the
709 * lowest unused one. To do this, binary-search using the
710 * counted B-tree to find the largest channel ID which is in a
711 * contiguous sequence from the beginning. (Precisely
712 * everything in that sequence must have ID equal to its tree
713 * index plus CHANNEL_NUMBER_OFFSET.)
714 */
715 tsize = count234(ssh->channels);
716
717 low = -1;
718 high = tsize;
719 while (high - low > 1) {
720 mid = (high + low) / 2;
721 c = index234(ssh->channels, mid);
722 if (c->localid == mid + CHANNEL_NUMBER_OFFSET)
723 low = mid; /* this one is fine */
724 else
725 high = mid; /* this one is past it */
726 }
727 /*
728 * Now low points to either -1, or the tree index of the
729 * largest ID in the initial sequence.
730 */
731 {
732 unsigned i = low + 1 + CHANNEL_NUMBER_OFFSET;
733 assert(NULL == find234(ssh->channels, &i, ssh_channelfind));
734 }
735 return low + 1 + CHANNEL_NUMBER_OFFSET;
736 }
737
738 static void c_write(Ssh ssh, const char *buf, int len)
739 {
740 if ((flags & FLAG_STDERR)) {
741 int i;
742 for (i = 0; i < len; i++)
743 if (buf[i] != '\r')
744 fputc(buf[i], stderr);
745 return;
746 }
747 from_backend(ssh->frontend, 1, buf, len);
748 }
749
750 static void c_write_untrusted(Ssh ssh, const char *buf, int len)
751 {
752 int i;
753 for (i = 0; i < len; i++) {
754 if (buf[i] == '\n')
755 c_write(ssh, "\r\n", 2);
756 else if ((buf[i] & 0x60) || (buf[i] == '\r'))
757 c_write(ssh, buf + i, 1);
758 }
759 }
760
761 static void c_write_str(Ssh ssh, const char *buf)
762 {
763 c_write(ssh, buf, strlen(buf));
764 }
765
766 /*
767 * Collect incoming data in the incoming packet buffer.
768 * Decipher and verify the packet when it is completely read.
769 * Drop SSH1_MSG_DEBUG and SSH1_MSG_IGNORE packets.
770 * Update the *data and *datalen variables.
771 * Return the additional nr of bytes needed, or 0 when
772 * a complete packet is available.
773 */
774 static int ssh1_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
775 {
776 struct rdpkt1_state_tag *st = &ssh->rdpkt1_state;
777
778 crBegin(ssh->ssh1_rdpkt_crstate);
779
780 next_packet:
781
782 ssh->pktin.type = 0;
783 ssh->pktin.length = 0;
784
785 for (st->i = st->len = 0; st->i < 4; st->i++) {
786 while ((*datalen) == 0)
787 crReturn(4 - st->i);
788 st->len = (st->len << 8) + **data;
789 (*data)++, (*datalen)--;
790 }
791
792 st->pad = 8 - (st->len % 8);
793 st->biglen = st->len + st->pad;
794 ssh->pktin.length = st->len - 5;
795
796 if (ssh->pktin.maxlen < st->biglen) {
797 ssh->pktin.maxlen = st->biglen;
798 ssh->pktin.data = srealloc(ssh->pktin.data, st->biglen + APIEXTRA);
799 }
800
801 st->to_read = st->biglen;
802 st->p = ssh->pktin.data;
803 while (st->to_read > 0) {
804 st->chunk = st->to_read;
805 while ((*datalen) == 0)
806 crReturn(st->to_read);
807 if (st->chunk > (*datalen))
808 st->chunk = (*datalen);
809 memcpy(st->p, *data, st->chunk);
810 *data += st->chunk;
811 *datalen -= st->chunk;
812 st->p += st->chunk;
813 st->to_read -= st->chunk;
814 }
815
816 if (ssh->cipher && detect_attack(ssh->crcda_ctx, ssh->pktin.data,
817 st->biglen, NULL)) {
818 bombout((ssh,"Network attack (CRC compensation) detected!"));
819 crReturn(0);
820 }
821
822 if (ssh->cipher)
823 ssh->cipher->decrypt(ssh->v1_cipher_ctx, ssh->pktin.data, st->biglen);
824
825 st->realcrc = crc32(ssh->pktin.data, st->biglen - 4);
826 st->gotcrc = GET_32BIT(ssh->pktin.data + st->biglen - 4);
827 if (st->gotcrc != st->realcrc) {
828 bombout((ssh,"Incorrect CRC received on packet"));
829 crReturn(0);
830 }
831
832 ssh->pktin.body = ssh->pktin.data + st->pad + 1;
833
834 if (ssh->v1_compressing) {
835 unsigned char *decompblk;
836 int decomplen;
837 zlib_decompress_block(ssh->sc_comp_ctx,
838 ssh->pktin.body - 1, ssh->pktin.length + 1,
839 &decompblk, &decomplen);
840
841 if (ssh->pktin.maxlen < st->pad + decomplen) {
842 ssh->pktin.maxlen = st->pad + decomplen;
843 ssh->pktin.data = srealloc(ssh->pktin.data,
844 ssh->pktin.maxlen + APIEXTRA);
845 ssh->pktin.body = ssh->pktin.data + st->pad + 1;
846 }
847
848 memcpy(ssh->pktin.body - 1, decompblk, decomplen);
849 sfree(decompblk);
850 ssh->pktin.length = decomplen - 1;
851 }
852
853 ssh->pktin.type = ssh->pktin.body[-1];
854
855 if (ssh->logctx)
856 log_packet(ssh->logctx,
857 PKT_INCOMING, ssh->pktin.type,
858 ssh1_pkt_type(ssh->pktin.type),
859 ssh->pktin.body, ssh->pktin.length);
860
861 if (ssh->pktin.type == SSH1_SMSG_STDOUT_DATA ||
862 ssh->pktin.type == SSH1_SMSG_STDERR_DATA ||
863 ssh->pktin.type == SSH1_MSG_DEBUG ||
864 ssh->pktin.type == SSH1_SMSG_AUTH_TIS_CHALLENGE ||
865 ssh->pktin.type == SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
866 long stringlen = GET_32BIT(ssh->pktin.body);
867 if (stringlen + 4 != ssh->pktin.length) {
868 bombout((ssh,"Received data packet with bogus string length"));
869 crReturn(0);
870 }
871 }
872
873 if (ssh->pktin.type == SSH1_MSG_DEBUG) {
874 /* log debug message */
875 char buf[512];
876 int stringlen = GET_32BIT(ssh->pktin.body);
877 strcpy(buf, "Remote debug message: ");
878 if (stringlen > 480)
879 stringlen = 480;
880 memcpy(buf + 8, ssh->pktin.body + 4, stringlen);
881 buf[8 + stringlen] = '\0';
882 logevent(buf);
883 goto next_packet;
884 } else if (ssh->pktin.type == SSH1_MSG_IGNORE) {
885 /* do nothing */
886 goto next_packet;
887 }
888
889 if (ssh->pktin.type == SSH1_MSG_DISCONNECT) {
890 /* log reason code in disconnect message */
891 char buf[256];
892 unsigned msglen = GET_32BIT(ssh->pktin.body);
893 unsigned nowlen;
894 strcpy(buf, "Remote sent disconnect: ");
895 nowlen = strlen(buf);
896 if (msglen > sizeof(buf) - nowlen - 1)
897 msglen = sizeof(buf) - nowlen - 1;
898 memcpy(buf + nowlen, ssh->pktin.body + 4, msglen);
899 buf[nowlen + msglen] = '\0';
900 /* logevent(buf); (this is now done within the bombout macro) */
901 bombout((ssh,"Server sent disconnect message:\n\"%s\"", buf+nowlen));
902 crReturn(0);
903 }
904
905 crFinish(0);
906 }
907
908 static int ssh2_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
909 {
910 struct rdpkt2_state_tag *st = &ssh->rdpkt2_state;
911
912 crBegin(ssh->ssh2_rdpkt_crstate);
913
914 next_packet:
915 ssh->pktin.type = 0;
916 ssh->pktin.length = 0;
917 if (ssh->sccipher)
918 st->cipherblk = ssh->sccipher->blksize;
919 else
920 st->cipherblk = 8;
921 if (st->cipherblk < 8)
922 st->cipherblk = 8;
923
924 if (ssh->pktin.maxlen < st->cipherblk) {
925 ssh->pktin.maxlen = st->cipherblk;
926 ssh->pktin.data = srealloc(ssh->pktin.data, st->cipherblk + APIEXTRA);
927 }
928
929 /*
930 * Acquire and decrypt the first block of the packet. This will
931 * contain the length and padding details.
932 */
933 for (st->i = st->len = 0; st->i < st->cipherblk; st->i++) {
934 while ((*datalen) == 0)
935 crReturn(st->cipherblk - st->i);
936 ssh->pktin.data[st->i] = *(*data)++;
937 (*datalen)--;
938 }
939
940 if (ssh->sccipher)
941 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
942 ssh->pktin.data, st->cipherblk);
943
944 /*
945 * Now get the length and padding figures.
946 */
947 st->len = GET_32BIT(ssh->pktin.data);
948 st->pad = ssh->pktin.data[4];
949
950 /*
951 * _Completely_ silly lengths should be stomped on before they
952 * do us any more damage.
953 */
954 if (st->len < 0 || st->pad < 0 || st->len + st->pad < 0) {
955 bombout((ssh,"Incoming packet was garbled on decryption"));
956 crReturn(0);
957 }
958
959 /*
960 * This enables us to deduce the payload length.
961 */
962 st->payload = st->len - st->pad - 1;
963
964 ssh->pktin.length = st->payload + 5;
965
966 /*
967 * So now we can work out the total packet length.
968 */
969 st->packetlen = st->len + 4;
970 st->maclen = ssh->scmac ? ssh->scmac->len : 0;
971
972 /*
973 * Adjust memory allocation if packet is too big.
974 */
975 if (ssh->pktin.maxlen < st->packetlen + st->maclen) {
976 ssh->pktin.maxlen = st->packetlen + st->maclen;
977 ssh->pktin.data = srealloc(ssh->pktin.data,
978 ssh->pktin.maxlen + APIEXTRA);
979 }
980
981 /*
982 * Read and decrypt the remainder of the packet.
983 */
984 for (st->i = st->cipherblk; st->i < st->packetlen + st->maclen;
985 st->i++) {
986 while ((*datalen) == 0)
987 crReturn(st->packetlen + st->maclen - st->i);
988 ssh->pktin.data[st->i] = *(*data)++;
989 (*datalen)--;
990 }
991 /* Decrypt everything _except_ the MAC. */
992 if (ssh->sccipher)
993 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
994 ssh->pktin.data + st->cipherblk,
995 st->packetlen - st->cipherblk);
996
997 /*
998 * Check the MAC.
999 */
1000 if (ssh->scmac
1001 && !ssh->scmac->verify(ssh->sc_mac_ctx, ssh->pktin.data, st->len + 4,
1002 st->incoming_sequence)) {
1003 bombout((ssh,"Incorrect MAC received on packet"));
1004 crReturn(0);
1005 }
1006 st->incoming_sequence++; /* whether or not we MACed */
1007
1008 /*
1009 * Decompress packet payload.
1010 */
1011 {
1012 unsigned char *newpayload;
1013 int newlen;
1014 if (ssh->sccomp &&
1015 ssh->sccomp->decompress(ssh->sc_comp_ctx,
1016 ssh->pktin.data + 5, ssh->pktin.length - 5,
1017 &newpayload, &newlen)) {
1018 if (ssh->pktin.maxlen < newlen + 5) {
1019 ssh->pktin.maxlen = newlen + 5;
1020 ssh->pktin.data = srealloc(ssh->pktin.data,
1021 ssh->pktin.maxlen + APIEXTRA);
1022 }
1023 ssh->pktin.length = 5 + newlen;
1024 memcpy(ssh->pktin.data + 5, newpayload, newlen);
1025 sfree(newpayload);
1026 }
1027 }
1028
1029 ssh->pktin.savedpos = 6;
1030 ssh->pktin.type = ssh->pktin.data[5];
1031
1032 if (ssh->logctx)
1033 log_packet(ssh->logctx, PKT_INCOMING, ssh->pktin.type,
1034 ssh2_pkt_type(ssh->pkt_ctx, ssh->pktin.type),
1035 ssh->pktin.data+6, ssh->pktin.length-6);
1036
1037 switch (ssh->pktin.type) {
1038 /*
1039 * These packets we must handle instantly.
1040 */
1041 case SSH2_MSG_DISCONNECT:
1042 {
1043 /* log reason code in disconnect message */
1044 char *buf;
1045 int nowlen;
1046 int reason = GET_32BIT(ssh->pktin.data + 6);
1047 unsigned msglen = GET_32BIT(ssh->pktin.data + 10);
1048
1049 if (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) {
1050 buf = dupprintf("Received disconnect message (%s)",
1051 ssh2_disconnect_reasons[reason]);
1052 } else {
1053 buf = dupprintf("Received disconnect message (unknown"
1054 " type %d)", reason);
1055 }
1056 logevent(buf);
1057 sfree(buf);
1058 buf = dupprintf("Disconnection message text: %n%.*s",
1059 &nowlen, msglen, ssh->pktin.data + 14);
1060 logevent(buf);
1061 bombout((ssh,"Server sent disconnect message\ntype %d (%s):\n\"%s\"",
1062 reason,
1063 (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) ?
1064 ssh2_disconnect_reasons[reason] : "unknown",
1065 buf+nowlen));
1066 sfree(buf);
1067 crReturn(0);
1068 }
1069 break;
1070 case SSH2_MSG_IGNORE:
1071 goto next_packet;
1072 case SSH2_MSG_DEBUG:
1073 {
1074 /* log the debug message */
1075 char buf[512];
1076 /* int display = ssh->pktin.body[6]; */
1077 int stringlen = GET_32BIT(ssh->pktin.data+7);
1078 int prefix;
1079 strcpy(buf, "Remote debug message: ");
1080 prefix = strlen(buf);
1081 if (stringlen > (int)(sizeof(buf)-prefix-1))
1082 stringlen = sizeof(buf)-prefix-1;
1083 memcpy(buf + prefix, ssh->pktin.data + 11, stringlen);
1084 buf[prefix + stringlen] = '\0';
1085 logevent(buf);
1086 }
1087 goto next_packet; /* FIXME: print the debug message */
1088
1089 /*
1090 * These packets we need do nothing about here.
1091 */
1092 case SSH2_MSG_UNIMPLEMENTED:
1093 case SSH2_MSG_SERVICE_REQUEST:
1094 case SSH2_MSG_SERVICE_ACCEPT:
1095 case SSH2_MSG_KEXINIT:
1096 case SSH2_MSG_NEWKEYS:
1097 case SSH2_MSG_KEXDH_INIT:
1098 case SSH2_MSG_KEXDH_REPLY:
1099 /* case SSH2_MSG_KEX_DH_GEX_REQUEST: duplicate case value */
1100 /* case SSH2_MSG_KEX_DH_GEX_GROUP: duplicate case value */
1101 case SSH2_MSG_KEX_DH_GEX_INIT:
1102 case SSH2_MSG_KEX_DH_GEX_REPLY:
1103 case SSH2_MSG_USERAUTH_REQUEST:
1104 case SSH2_MSG_USERAUTH_FAILURE:
1105 case SSH2_MSG_USERAUTH_SUCCESS:
1106 case SSH2_MSG_USERAUTH_BANNER:
1107 case SSH2_MSG_USERAUTH_PK_OK:
1108 /* case SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ: duplicate case value */
1109 /* case SSH2_MSG_USERAUTH_INFO_REQUEST: duplicate case value */
1110 case SSH2_MSG_USERAUTH_INFO_RESPONSE:
1111 case SSH2_MSG_GLOBAL_REQUEST:
1112 case SSH2_MSG_REQUEST_SUCCESS:
1113 case SSH2_MSG_REQUEST_FAILURE:
1114 case SSH2_MSG_CHANNEL_OPEN:
1115 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION:
1116 case SSH2_MSG_CHANNEL_OPEN_FAILURE:
1117 case SSH2_MSG_CHANNEL_WINDOW_ADJUST:
1118 case SSH2_MSG_CHANNEL_DATA:
1119 case SSH2_MSG_CHANNEL_EXTENDED_DATA:
1120 case SSH2_MSG_CHANNEL_EOF:
1121 case SSH2_MSG_CHANNEL_CLOSE:
1122 case SSH2_MSG_CHANNEL_REQUEST:
1123 case SSH2_MSG_CHANNEL_SUCCESS:
1124 case SSH2_MSG_CHANNEL_FAILURE:
1125 break;
1126
1127 /*
1128 * For anything else we send SSH2_MSG_UNIMPLEMENTED.
1129 */
1130 default:
1131 ssh2_pkt_init(ssh, SSH2_MSG_UNIMPLEMENTED);
1132 ssh2_pkt_adduint32(ssh, st->incoming_sequence - 1);
1133 ssh2_pkt_send(ssh);
1134 break;
1135 }
1136
1137 crFinish(0);
1138 }
1139
1140 static void ssh1_pktout_size(Ssh ssh, int len)
1141 {
1142 int pad, biglen;
1143
1144 len += 5; /* type and CRC */
1145 pad = 8 - (len % 8);
1146 biglen = len + pad;
1147
1148 ssh->pktout.length = len - 5;
1149 if (ssh->pktout.maxlen < biglen) {
1150 ssh->pktout.maxlen = biglen;
1151 #ifdef MSCRYPTOAPI
1152 /* Allocate enough buffer space for extra block
1153 * for MS CryptEncrypt() */
1154 ssh->pktout.data = srealloc(ssh->pktout.data, biglen + 12);
1155 #else
1156 ssh->pktout.data = srealloc(ssh->pktout.data, biglen + 4);
1157 #endif
1158 }
1159 ssh->pktout.body = ssh->pktout.data + 4 + pad + 1;
1160 }
1161
1162 static void s_wrpkt_start(Ssh ssh, int type, int len)
1163 {
1164 ssh1_pktout_size(ssh, len);
1165 ssh->pktout.type = type;
1166 }
1167
1168 static int s_wrpkt_prepare(Ssh ssh)
1169 {
1170 int pad, biglen, i;
1171 unsigned long crc;
1172 #ifdef __SC__
1173 /*
1174 * XXX various versions of SC (including 8.8.4) screw up the
1175 * register allocation in this function and use the same register
1176 * (D6) for len and as a temporary, with predictable results. The
1177 * following sledgehammer prevents this.
1178 */
1179 volatile
1180 #endif
1181 int len;
1182
1183 ssh->pktout.body[-1] = ssh->pktout.type;
1184
1185 if (ssh->logctx)
1186 log_packet(ssh->logctx, PKT_OUTGOING, ssh->pktout.type,
1187 ssh1_pkt_type(ssh->pktout.type),
1188 ssh->pktout.body, ssh->pktout.length);
1189
1190 if (ssh->v1_compressing) {
1191 unsigned char *compblk;
1192 int complen;
1193 zlib_compress_block(ssh->cs_comp_ctx,
1194 ssh->pktout.body - 1, ssh->pktout.length + 1,
1195 &compblk, &complen);
1196 ssh1_pktout_size(ssh, complen - 1);
1197 memcpy(ssh->pktout.body - 1, compblk, complen);
1198 sfree(compblk);
1199 }
1200
1201 len = ssh->pktout.length + 5; /* type and CRC */
1202 pad = 8 - (len % 8);
1203 biglen = len + pad;
1204
1205 for (i = 0; i < pad; i++)
1206 ssh->pktout.data[i + 4] = random_byte();
1207 crc = crc32(ssh->pktout.data + 4, biglen - 4);
1208 PUT_32BIT(ssh->pktout.data + biglen, crc);
1209 PUT_32BIT(ssh->pktout.data, len);
1210
1211 if (ssh->cipher)
1212 ssh->cipher->encrypt(ssh->v1_cipher_ctx, ssh->pktout.data + 4, biglen);
1213
1214 return biglen + 4;
1215 }
1216
1217 static void s_wrpkt(Ssh ssh)
1218 {
1219 int len, backlog;
1220 len = s_wrpkt_prepare(ssh);
1221 backlog = sk_write(ssh->s, (char *)ssh->pktout.data, len);
1222 if (backlog > SSH_MAX_BACKLOG)
1223 ssh_throttle_all(ssh, 1, backlog);
1224 }
1225
1226 static void s_wrpkt_defer(Ssh ssh)
1227 {
1228 int len;
1229 len = s_wrpkt_prepare(ssh);
1230 if (ssh->deferred_len + len > ssh->deferred_size) {
1231 ssh->deferred_size = ssh->deferred_len + len + 128;
1232 ssh->deferred_send_data = srealloc(ssh->deferred_send_data,
1233 ssh->deferred_size);
1234 }
1235 memcpy(ssh->deferred_send_data + ssh->deferred_len, ssh->pktout.data, len);
1236 ssh->deferred_len += len;
1237 }
1238
1239 /*
1240 * Construct a packet with the specified contents.
1241 */
1242 static void construct_packet(Ssh ssh, int pkttype, va_list ap1, va_list ap2)
1243 {
1244 unsigned char *p, *argp, argchar;
1245 unsigned long argint;
1246 int pktlen, argtype, arglen;
1247 Bignum bn;
1248
1249 pktlen = 0;
1250 while ((argtype = va_arg(ap1, int)) != PKT_END) {
1251 switch (argtype) {
1252 case PKT_INT:
1253 (void) va_arg(ap1, int);
1254 pktlen += 4;
1255 break;
1256 case PKT_CHAR:
1257 (void) va_arg(ap1, int);
1258 pktlen++;
1259 break;
1260 case PKT_DATA:
1261 (void) va_arg(ap1, unsigned char *);
1262 arglen = va_arg(ap1, int);
1263 pktlen += arglen;
1264 break;
1265 case PKT_STR:
1266 argp = va_arg(ap1, unsigned char *);
1267 arglen = strlen((char *)argp);
1268 pktlen += 4 + arglen;
1269 break;
1270 case PKT_BIGNUM:
1271 bn = va_arg(ap1, Bignum);
1272 pktlen += ssh1_bignum_length(bn);
1273 break;
1274 default:
1275 assert(0);
1276 }
1277 }
1278
1279 s_wrpkt_start(ssh, pkttype, pktlen);
1280 p = ssh->pktout.body;
1281
1282 while ((argtype = va_arg(ap2, int)) != PKT_END) {
1283 switch (argtype) {
1284 case PKT_INT:
1285 argint = va_arg(ap2, int);
1286 PUT_32BIT(p, argint);
1287 p += 4;
1288 break;
1289 case PKT_CHAR:
1290 argchar = (unsigned char) va_arg(ap2, int);
1291 *p = argchar;
1292 p++;
1293 break;
1294 case PKT_DATA:
1295 argp = va_arg(ap2, unsigned char *);
1296 arglen = va_arg(ap2, int);
1297 memcpy(p, argp, arglen);
1298 p += arglen;
1299 break;
1300 case PKT_STR:
1301 argp = va_arg(ap2, unsigned char *);
1302 arglen = strlen((char *)argp);
1303 PUT_32BIT(p, arglen);
1304 memcpy(p + 4, argp, arglen);
1305 p += 4 + arglen;
1306 break;
1307 case PKT_BIGNUM:
1308 bn = va_arg(ap2, Bignum);
1309 p += ssh1_write_bignum(p, bn);
1310 break;
1311 }
1312 }
1313 }
1314
1315 static void send_packet(Ssh ssh, int pkttype, ...)
1316 {
1317 va_list ap1, ap2;
1318 va_start(ap1, pkttype);
1319 va_start(ap2, pkttype);
1320 construct_packet(ssh, pkttype, ap1, ap2);
1321 s_wrpkt(ssh);
1322 }
1323
1324 static void defer_packet(Ssh ssh, int pkttype, ...)
1325 {
1326 va_list ap1, ap2;
1327 va_start(ap1, pkttype);
1328 va_start(ap2, pkttype);
1329 construct_packet(ssh, pkttype, ap1, ap2);
1330 s_wrpkt_defer(ssh);
1331 }
1332
1333 static int ssh_versioncmp(char *a, char *b)
1334 {
1335 char *ae, *be;
1336 unsigned long av, bv;
1337
1338 av = strtoul(a, &ae, 10);
1339 bv = strtoul(b, &be, 10);
1340 if (av != bv)
1341 return (av < bv ? -1 : +1);
1342 if (*ae == '.')
1343 ae++;
1344 if (*be == '.')
1345 be++;
1346 av = strtoul(ae, &ae, 10);
1347 bv = strtoul(be, &be, 10);
1348 if (av != bv)
1349 return (av < bv ? -1 : +1);
1350 return 0;
1351 }
1352
1353 /*
1354 * Utility routines for putting an SSH-protocol `string' and
1355 * `uint32' into a SHA state.
1356 */
1357 #include <stdio.h>
1358 static void sha_string(SHA_State * s, void *str, int len)
1359 {
1360 unsigned char lenblk[4];
1361 PUT_32BIT(lenblk, len);
1362 SHA_Bytes(s, lenblk, 4);
1363 SHA_Bytes(s, str, len);
1364 }
1365
1366 static void sha_uint32(SHA_State * s, unsigned i)
1367 {
1368 unsigned char intblk[4];
1369 PUT_32BIT(intblk, i);
1370 SHA_Bytes(s, intblk, 4);
1371 }
1372
1373 /*
1374 * SSH2 packet construction functions.
1375 */
1376 static void ssh2_pkt_ensure(Ssh ssh, int length)
1377 {
1378 if (ssh->pktout.maxlen < length) {
1379 ssh->pktout.maxlen = length + 256;
1380 ssh->pktout.data = srealloc(ssh->pktout.data,
1381 ssh->pktout.maxlen + APIEXTRA);
1382 if (!ssh->pktout.data)
1383 fatalbox("Out of memory");
1384 }
1385 }
1386 static void ssh2_pkt_adddata(Ssh ssh, void *data, int len)
1387 {
1388 ssh->pktout.length += len;
1389 ssh2_pkt_ensure(ssh, ssh->pktout.length);
1390 memcpy(ssh->pktout.data + ssh->pktout.length - len, data, len);
1391 }
1392 static void ssh2_pkt_addbyte(Ssh ssh, unsigned char byte)
1393 {
1394 ssh2_pkt_adddata(ssh, &byte, 1);
1395 }
1396 static void ssh2_pkt_init(Ssh ssh, int pkt_type)
1397 {
1398 ssh->pktout.length = 5;
1399 ssh2_pkt_addbyte(ssh, (unsigned char) pkt_type);
1400 }
1401 static void ssh2_pkt_addbool(Ssh ssh, unsigned char value)
1402 {
1403 ssh2_pkt_adddata(ssh, &value, 1);
1404 }
1405 static void ssh2_pkt_adduint32(Ssh ssh, unsigned long value)
1406 {
1407 unsigned char x[4];
1408 PUT_32BIT(x, value);
1409 ssh2_pkt_adddata(ssh, x, 4);
1410 }
1411 static void ssh2_pkt_addstring_start(Ssh ssh)
1412 {
1413 ssh2_pkt_adduint32(ssh, 0);
1414 ssh->pktout.savedpos = ssh->pktout.length;
1415 }
1416 static void ssh2_pkt_addstring_str(Ssh ssh, char *data)
1417 {
1418 ssh2_pkt_adddata(ssh, data, strlen(data));
1419 PUT_32BIT(ssh->pktout.data + ssh->pktout.savedpos - 4,
1420 ssh->pktout.length - ssh->pktout.savedpos);
1421 }
1422 static void ssh2_pkt_addstring_data(Ssh ssh, char *data, int len)
1423 {
1424 ssh2_pkt_adddata(ssh, data, len);
1425 PUT_32BIT(ssh->pktout.data + ssh->pktout.savedpos - 4,
1426 ssh->pktout.length - ssh->pktout.savedpos);
1427 }
1428 static void ssh2_pkt_addstring(Ssh ssh, char *data)
1429 {
1430 ssh2_pkt_addstring_start(ssh);
1431 ssh2_pkt_addstring_str(ssh, data);
1432 }
1433 static unsigned char *ssh2_mpint_fmt(Bignum b, int *len)
1434 {
1435 unsigned char *p;
1436 int i, n = (bignum_bitcount(b) + 7) / 8;
1437 p = smalloc(n + 1);
1438 if (!p)
1439 fatalbox("out of memory");
1440 p[0] = 0;
1441 for (i = 1; i <= n; i++)
1442 p[i] = bignum_byte(b, n - i);
1443 i = 0;
1444 while (i <= n && p[i] == 0 && (p[i + 1] & 0x80) == 0)
1445 i++;
1446 memmove(p, p + i, n + 1 - i);
1447 *len = n + 1 - i;
1448 return p;
1449 }
1450 static void ssh2_pkt_addmp(Ssh ssh, Bignum b)
1451 {
1452 unsigned char *p;
1453 int len;
1454 p = ssh2_mpint_fmt(b, &len);
1455 ssh2_pkt_addstring_start(ssh);
1456 ssh2_pkt_addstring_data(ssh, (char *)p, len);
1457 sfree(p);
1458 }
1459
1460 /*
1461 * Construct an SSH2 final-form packet: compress it, encrypt it,
1462 * put the MAC on it. Final packet, ready to be sent, is stored in
1463 * ssh->pktout.data. Total length is returned.
1464 */
1465 static int ssh2_pkt_construct(Ssh ssh)
1466 {
1467 int cipherblk, maclen, padding, i;
1468
1469 if (ssh->logctx)
1470 log_packet(ssh->logctx, PKT_OUTGOING, ssh->pktout.data[5],
1471 ssh2_pkt_type(ssh->pkt_ctx, ssh->pktout.data[5]),
1472 ssh->pktout.data + 6, ssh->pktout.length - 6);
1473
1474 /*
1475 * Compress packet payload.
1476 */
1477 {
1478 unsigned char *newpayload;
1479 int newlen;
1480 if (ssh->cscomp &&
1481 ssh->cscomp->compress(ssh->cs_comp_ctx, ssh->pktout.data + 5,
1482 ssh->pktout.length - 5,
1483 &newpayload, &newlen)) {
1484 ssh->pktout.length = 5;
1485 ssh2_pkt_adddata(ssh, newpayload, newlen);
1486 sfree(newpayload);
1487 }
1488 }
1489
1490 /*
1491 * Add padding. At least four bytes, and must also bring total
1492 * length (minus MAC) up to a multiple of the block size.
1493 */
1494 cipherblk = ssh->cscipher ? ssh->cscipher->blksize : 8; /* block size */
1495 cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */
1496 padding = 4;
1497 padding +=
1498 (cipherblk - (ssh->pktout.length + padding) % cipherblk) % cipherblk;
1499 maclen = ssh->csmac ? ssh->csmac->len : 0;
1500 ssh2_pkt_ensure(ssh, ssh->pktout.length + padding + maclen);
1501 ssh->pktout.data[4] = padding;
1502 for (i = 0; i < padding; i++)
1503 ssh->pktout.data[ssh->pktout.length + i] = random_byte();
1504 PUT_32BIT(ssh->pktout.data, ssh->pktout.length + padding - 4);
1505 if (ssh->csmac)
1506 ssh->csmac->generate(ssh->cs_mac_ctx, ssh->pktout.data,
1507 ssh->pktout.length + padding,
1508 ssh->v2_outgoing_sequence);
1509 ssh->v2_outgoing_sequence++; /* whether or not we MACed */
1510
1511 if (ssh->cscipher)
1512 ssh->cscipher->encrypt(ssh->cs_cipher_ctx,
1513 ssh->pktout.data, ssh->pktout.length + padding);
1514
1515 /* Ready-to-send packet starts at ssh->pktout.data. We return length. */
1516 return ssh->pktout.length + padding + maclen;
1517 }
1518
1519 /*
1520 * Construct and send an SSH2 packet immediately.
1521 */
1522 static void ssh2_pkt_send(Ssh ssh)
1523 {
1524 int len;
1525 int backlog;
1526 len = ssh2_pkt_construct(ssh);
1527 backlog = sk_write(ssh->s, (char *)ssh->pktout.data, len);
1528 if (backlog > SSH_MAX_BACKLOG)
1529 ssh_throttle_all(ssh, 1, backlog);
1530 }
1531
1532 /*
1533 * Construct an SSH2 packet and add it to a deferred data block.
1534 * Useful for sending multiple packets in a single sk_write() call,
1535 * to prevent a traffic-analysing listener from being able to work
1536 * out the length of any particular packet (such as the password
1537 * packet).
1538 *
1539 * Note that because SSH2 sequence-numbers its packets, this can
1540 * NOT be used as an m4-style `defer' allowing packets to be
1541 * constructed in one order and sent in another.
1542 */
1543 static void ssh2_pkt_defer(Ssh ssh)
1544 {
1545 int len = ssh2_pkt_construct(ssh);
1546 if (ssh->deferred_len + len > ssh->deferred_size) {
1547 ssh->deferred_size = ssh->deferred_len + len + 128;
1548 ssh->deferred_send_data = srealloc(ssh->deferred_send_data,
1549 ssh->deferred_size);
1550 }
1551 memcpy(ssh->deferred_send_data + ssh->deferred_len, ssh->pktout.data, len);
1552 ssh->deferred_len += len;
1553 }
1554
1555 /*
1556 * Send the whole deferred data block constructed by
1557 * ssh2_pkt_defer() or SSH1's defer_packet().
1558 */
1559 static void ssh_pkt_defersend(Ssh ssh)
1560 {
1561 int backlog;
1562 backlog = sk_write(ssh->s, (char *)ssh->deferred_send_data,
1563 ssh->deferred_len);
1564 ssh->deferred_len = ssh->deferred_size = 0;
1565 sfree(ssh->deferred_send_data);
1566 ssh->deferred_send_data = NULL;
1567 if (backlog > SSH_MAX_BACKLOG)
1568 ssh_throttle_all(ssh, 1, backlog);
1569 }
1570
1571 #if 0
1572 void bndebug(char *string, Bignum b)
1573 {
1574 unsigned char *p;
1575 int i, len;
1576 p = ssh2_mpint_fmt(b, &len);
1577 debug(("%s", string));
1578 for (i = 0; i < len; i++)
1579 debug((" %02x", p[i]));
1580 debug(("\n"));
1581 sfree(p);
1582 }
1583 #endif
1584
1585 static void sha_mpint(SHA_State * s, Bignum b)
1586 {
1587 unsigned char *p;
1588 int len;
1589 p = ssh2_mpint_fmt(b, &len);
1590 sha_string(s, p, len);
1591 sfree(p);
1592 }
1593
1594 /*
1595 * SSH2 packet decode functions.
1596 */
1597 static unsigned long ssh2_pkt_getuint32(Ssh ssh)
1598 {
1599 unsigned long value;
1600 if (ssh->pktin.length - ssh->pktin.savedpos < 4)
1601 return 0; /* arrgh, no way to decline (FIXME?) */
1602 value = GET_32BIT(ssh->pktin.data + ssh->pktin.savedpos);
1603 ssh->pktin.savedpos += 4;
1604 return value;
1605 }
1606 static int ssh2_pkt_getbool(Ssh ssh)
1607 {
1608 unsigned long value;
1609 if (ssh->pktin.length - ssh->pktin.savedpos < 1)
1610 return 0; /* arrgh, no way to decline (FIXME?) */
1611 value = ssh->pktin.data[ssh->pktin.savedpos] != 0;
1612 ssh->pktin.savedpos++;
1613 return value;
1614 }
1615 static void ssh2_pkt_getstring(Ssh ssh, char **p, int *length)
1616 {
1617 int len;
1618 *p = NULL;
1619 *length = 0;
1620 if (ssh->pktin.length - ssh->pktin.savedpos < 4)
1621 return;
1622 len = GET_32BIT(ssh->pktin.data + ssh->pktin.savedpos);
1623 if (len < 0)
1624 return;
1625 *length = len;
1626 ssh->pktin.savedpos += 4;
1627 if (ssh->pktin.length - ssh->pktin.savedpos < *length)
1628 return;
1629 *p = (char *)(ssh->pktin.data + ssh->pktin.savedpos);
1630 ssh->pktin.savedpos += *length;
1631 }
1632 static Bignum ssh2_pkt_getmp(Ssh ssh)
1633 {
1634 char *p;
1635 int length;
1636 Bignum b;
1637
1638 ssh2_pkt_getstring(ssh, &p, &length);
1639 if (!p)
1640 return NULL;
1641 if (p[0] & 0x80) {
1642 bombout((ssh,"internal error: Can't handle negative mpints"));
1643 return NULL;
1644 }
1645 b = bignum_from_bytes((unsigned char *)p, length);
1646 return b;
1647 }
1648
1649 /*
1650 * Helper function to add an SSH2 signature blob to a packet.
1651 * Expects to be shown the public key blob as well as the signature
1652 * blob. Normally works just like ssh2_pkt_addstring, but will
1653 * fiddle with the signature packet if necessary for
1654 * BUG_SSH2_RSA_PADDING.
1655 */
1656 static void ssh2_add_sigblob(Ssh ssh, void *pkblob_v, int pkblob_len,
1657 void *sigblob_v, int sigblob_len)
1658 {
1659 unsigned char *pkblob = (unsigned char *)pkblob_v;
1660 unsigned char *sigblob = (unsigned char *)sigblob_v;
1661
1662 /* dmemdump(pkblob, pkblob_len); */
1663 /* dmemdump(sigblob, sigblob_len); */
1664
1665 /*
1666 * See if this is in fact an ssh-rsa signature and a buggy
1667 * server; otherwise we can just do this the easy way.
1668 */
1669 if ((ssh->remote_bugs & BUG_SSH2_RSA_PADDING) &&
1670 (GET_32BIT(pkblob) == 7 && !memcmp(pkblob+4, "ssh-rsa", 7))) {
1671 int pos, len, siglen;
1672
1673 /*
1674 * Find the byte length of the modulus.
1675 */
1676
1677 pos = 4+7; /* skip over "ssh-rsa" */
1678 pos += 4 + GET_32BIT(pkblob+pos); /* skip over exponent */
1679 len = GET_32BIT(pkblob+pos); /* find length of modulus */
1680 pos += 4; /* find modulus itself */
1681 while (len > 0 && pkblob[pos] == 0)
1682 len--, pos++;
1683 /* debug(("modulus length is %d\n", len)); */
1684
1685 /*
1686 * Now find the signature integer.
1687 */
1688 pos = 4+7; /* skip over "ssh-rsa" */
1689 siglen = GET_32BIT(sigblob+pos);
1690 /* debug(("signature length is %d\n", siglen)); */
1691
1692 if (len != siglen) {
1693 unsigned char newlen[4];
1694 ssh2_pkt_addstring_start(ssh);
1695 ssh2_pkt_addstring_data(ssh, (char *)sigblob, pos);
1696 /* dmemdump(sigblob, pos); */
1697 pos += 4; /* point to start of actual sig */
1698 PUT_32BIT(newlen, len);
1699 ssh2_pkt_addstring_data(ssh, (char *)newlen, 4);
1700 /* dmemdump(newlen, 4); */
1701 newlen[0] = 0;
1702 while (len-- > siglen) {
1703 ssh2_pkt_addstring_data(ssh, (char *)newlen, 1);
1704 /* dmemdump(newlen, 1); */
1705 }
1706 ssh2_pkt_addstring_data(ssh, (char *)(sigblob+pos), siglen);
1707 /* dmemdump(sigblob+pos, siglen); */
1708 return;
1709 }
1710
1711 /* Otherwise fall through and do it the easy way. */
1712 }
1713
1714 ssh2_pkt_addstring_start(ssh);
1715 ssh2_pkt_addstring_data(ssh, (char *)sigblob, sigblob_len);
1716 }
1717
1718 /*
1719 * Examine the remote side's version string and compare it against
1720 * a list of known buggy implementations.
1721 */
1722 static void ssh_detect_bugs(Ssh ssh, char *vstring)
1723 {
1724 char *imp; /* pointer to implementation part */
1725 imp = vstring;
1726 imp += strcspn(imp, "-");
1727 if (*imp) imp++;
1728 imp += strcspn(imp, "-");
1729 if (*imp) imp++;
1730
1731 ssh->remote_bugs = 0;
1732
1733 if (ssh->cfg.sshbug_ignore1 == FORCE_ON ||
1734 (ssh->cfg.sshbug_ignore1 == AUTO &&
1735 (!strcmp(imp, "1.2.18") || !strcmp(imp, "1.2.19") ||
1736 !strcmp(imp, "1.2.20") || !strcmp(imp, "1.2.21") ||
1737 !strcmp(imp, "1.2.22") || !strcmp(imp, "Cisco-1.25")))) {
1738 /*
1739 * These versions don't support SSH1_MSG_IGNORE, so we have
1740 * to use a different defence against password length
1741 * sniffing.
1742 */
1743 ssh->remote_bugs |= BUG_CHOKES_ON_SSH1_IGNORE;
1744 logevent("We believe remote version has SSH1 ignore bug");
1745 }
1746
1747 if (ssh->cfg.sshbug_plainpw1 == FORCE_ON ||
1748 (ssh->cfg.sshbug_plainpw1 == AUTO &&
1749 (!strcmp(imp, "Cisco-1.25")))) {
1750 /*
1751 * These versions need a plain password sent; they can't
1752 * handle having a null and a random length of data after
1753 * the password.
1754 */
1755 ssh->remote_bugs |= BUG_NEEDS_SSH1_PLAIN_PASSWORD;
1756 logevent("We believe remote version needs a plain SSH1 password");
1757 }
1758
1759 if (ssh->cfg.sshbug_rsa1 == FORCE_ON ||
1760 (ssh->cfg.sshbug_rsa1 == AUTO &&
1761 (!strcmp(imp, "Cisco-1.25")))) {
1762 /*
1763 * These versions apparently have no clue whatever about
1764 * RSA authentication and will panic and die if they see
1765 * an AUTH_RSA message.
1766 */
1767 ssh->remote_bugs |= BUG_CHOKES_ON_RSA;
1768 logevent("We believe remote version can't handle RSA authentication");
1769 }
1770
1771 if (ssh->cfg.sshbug_hmac2 == FORCE_ON ||
1772 (ssh->cfg.sshbug_hmac2 == AUTO &&
1773 (wc_match("2.1.0*", imp) || wc_match("2.0.*", imp) ||
1774 wc_match("2.2.0*", imp) || wc_match("2.3.0*", imp) ||
1775 wc_match("2.1 *", imp)))) {
1776 /*
1777 * These versions have the HMAC bug.
1778 */
1779 ssh->remote_bugs |= BUG_SSH2_HMAC;
1780 logevent("We believe remote version has SSH2 HMAC bug");
1781 }
1782
1783 if (ssh->cfg.sshbug_derivekey2 == FORCE_ON ||
1784 (ssh->cfg.sshbug_derivekey2 == AUTO &&
1785 (wc_match("2.0.0*", imp) || wc_match("2.0.10*", imp) ))) {
1786 /*
1787 * These versions have the key-derivation bug (failing to
1788 * include the literal shared secret in the hashes that
1789 * generate the keys).
1790 */
1791 ssh->remote_bugs |= BUG_SSH2_DERIVEKEY;
1792 logevent("We believe remote version has SSH2 key-derivation bug");
1793 }
1794
1795 if (ssh->cfg.sshbug_rsapad2 == FORCE_ON ||
1796 (ssh->cfg.sshbug_rsapad2 == AUTO &&
1797 (wc_match("OpenSSH_2.[5-9]*", imp) ||
1798 wc_match("OpenSSH_3.[0-2]*", imp)))) {
1799 /*
1800 * These versions have the SSH2 RSA padding bug.
1801 */
1802 ssh->remote_bugs |= BUG_SSH2_RSA_PADDING;
1803 logevent("We believe remote version has SSH2 RSA padding bug");
1804 }
1805
1806 if (ssh->cfg.sshbug_pksessid2 == FORCE_ON ||
1807 (ssh->cfg.sshbug_pksessid2 == AUTO &&
1808 wc_match("OpenSSH_2.[0-2]*", imp))) {
1809 /*
1810 * These versions have the SSH2 session-ID bug in
1811 * public-key authentication.
1812 */
1813 ssh->remote_bugs |= BUG_SSH2_PK_SESSIONID;
1814 logevent("We believe remote version has SSH2 public-key-session-ID bug");
1815 }
1816
1817 if (ssh->cfg.sshbug_dhgex2 == FORCE_ON) {
1818 /*
1819 * User specified the SSH2 DH GEX bug.
1820 */
1821 ssh->remote_bugs |= BUG_SSH2_DH_GEX;
1822 logevent("We believe remote version has SSH2 DH group exchange bug");
1823 }
1824 }
1825
1826 static int do_ssh_init(Ssh ssh, unsigned char c)
1827 {
1828 struct do_ssh_init_state {
1829 int vslen;
1830 char version[10];
1831 char *vstring;
1832 int vstrsize;
1833 int i;
1834 int proto1, proto2;
1835 };
1836 crState(do_ssh_init_state);
1837
1838 crBegin(ssh->do_ssh_init_crstate);
1839
1840 /* Search for the string "SSH-" in the input. */
1841 s->i = 0;
1842 while (1) {
1843 static const int transS[] = { 1, 2, 2, 1 };
1844 static const int transH[] = { 0, 0, 3, 0 };
1845 static const int transminus[] = { 0, 0, 0, -1 };
1846 if (c == 'S')
1847 s->i = transS[s->i];
1848 else if (c == 'H')
1849 s->i = transH[s->i];
1850 else if (c == '-')
1851 s->i = transminus[s->i];
1852 else
1853 s->i = 0;
1854 if (s->i < 0)
1855 break;
1856 crReturn(1); /* get another character */
1857 }
1858
1859 s->vstrsize = 16;
1860 s->vstring = smalloc(s->vstrsize);
1861 strcpy(s->vstring, "SSH-");
1862 s->vslen = 4;
1863 s->i = 0;
1864 while (1) {
1865 crReturn(1); /* get another char */
1866 if (s->vslen >= s->vstrsize - 1) {
1867 s->vstrsize += 16;
1868 s->vstring = srealloc(s->vstring, s->vstrsize);
1869 }
1870 s->vstring[s->vslen++] = c;
1871 if (s->i >= 0) {
1872 if (c == '-') {
1873 s->version[s->i] = '\0';
1874 s->i = -1;
1875 } else if (s->i < sizeof(s->version) - 1)
1876 s->version[s->i++] = c;
1877 } else if (c == '\012')
1878 break;
1879 }
1880
1881 ssh->agentfwd_enabled = FALSE;
1882 ssh->rdpkt2_state.incoming_sequence = 0;
1883
1884 s->vstring[s->vslen] = 0;
1885 s->vstring[strcspn(s->vstring, "\r\n")] = '\0';/* remove EOL chars */
1886 {
1887 char *vlog;
1888 vlog = smalloc(20 + s->vslen);
1889 sprintf(vlog, "Server version: %s", s->vstring);
1890 logevent(vlog);
1891 sfree(vlog);
1892 }
1893 ssh_detect_bugs(ssh, s->vstring);
1894
1895 /*
1896 * Decide which SSH protocol version to support.
1897 */
1898
1899 /* Anything strictly below "2.0" means protocol 1 is supported. */
1900 s->proto1 = ssh_versioncmp(s->version, "2.0") < 0;
1901 /* Anything greater or equal to "1.99" means protocol 2 is supported. */
1902 s->proto2 = ssh_versioncmp(s->version, "1.99") >= 0;
1903
1904 if (ssh->cfg.sshprot == 0 && !s->proto1) {
1905 bombout((ssh,"SSH protocol version 1 required by user but not provided by server"));
1906 crReturn(0);
1907 }
1908 if (ssh->cfg.sshprot == 3 && !s->proto2) {
1909 bombout((ssh,"SSH protocol version 2 required by user but not provided by server"));
1910 crReturn(0);
1911 }
1912
1913 if (s->proto2 && (ssh->cfg.sshprot >= 2 || !s->proto1)) {
1914 /*
1915 * Use v2 protocol.
1916 */
1917 char verstring[80], vlog[100];
1918 sprintf(verstring, "SSH-2.0-%s", sshver);
1919 SHA_Init(&ssh->exhashbase);
1920 /*
1921 * Hash our version string and their version string.
1922 */
1923 sha_string(&ssh->exhashbase, verstring, strlen(verstring));
1924 sha_string(&ssh->exhashbase, s->vstring, strcspn(s->vstring, "\r\n"));
1925 sprintf(vlog, "We claim version: %s", verstring);
1926 logevent(vlog);
1927 strcat(verstring, "\012");
1928 logevent("Using SSH protocol version 2");
1929 sk_write(ssh->s, verstring, strlen(verstring));
1930 ssh->protocol = ssh2_protocol;
1931 ssh->version = 2;
1932 ssh->s_rdpkt = ssh2_rdpkt;
1933 } else {
1934 /*
1935 * Use v1 protocol.
1936 */
1937 char verstring[80], vlog[100];
1938 sprintf(verstring, "SSH-%s-%s",
1939 (ssh_versioncmp(s->version, "1.5") <= 0 ? s->version : "1.5"),
1940 sshver);
1941 sprintf(vlog, "We claim version: %s", verstring);
1942 logevent(vlog);
1943 strcat(verstring, "\012");
1944
1945 logevent("Using SSH protocol version 1");
1946 sk_write(ssh->s, verstring, strlen(verstring));
1947 ssh->protocol = ssh1_protocol;
1948 ssh->version = 1;
1949 ssh->s_rdpkt = ssh1_rdpkt;
1950 }
1951 ssh->state = SSH_STATE_BEFORE_SIZE;
1952
1953 sfree(s->vstring);
1954
1955 crFinish(0);
1956 }
1957
1958 static void ssh_gotdata(Ssh ssh, unsigned char *data, int datalen)
1959 {
1960 crBegin(ssh->ssh_gotdata_crstate);
1961
1962 /*
1963 * To begin with, feed the characters one by one to the
1964 * protocol initialisation / selection function do_ssh_init().
1965 * When that returns 0, we're done with the initial greeting
1966 * exchange and can move on to packet discipline.
1967 */
1968 while (1) {
1969 int ret; /* need not be kept across crReturn */
1970 if (datalen == 0)
1971 crReturnV; /* more data please */
1972 ret = do_ssh_init(ssh, *data);
1973 data++;
1974 datalen--;
1975 if (ret == 0)
1976 break;
1977 }
1978
1979 /*
1980 * We emerge from that loop when the initial negotiation is
1981 * over and we have selected an s_rdpkt function. Now pass
1982 * everything to s_rdpkt, and then pass the resulting packets
1983 * to the proper protocol handler.
1984 */
1985 if (datalen == 0)
1986 crReturnV;
1987 while (1) {
1988 while (datalen > 0) {
1989 if (ssh->s_rdpkt(ssh, &data, &datalen) == 0) {
1990 if (ssh->state == SSH_STATE_CLOSED) {
1991 return;
1992 }
1993 ssh->protocol(ssh, NULL, 0, 1);
1994 if (ssh->state == SSH_STATE_CLOSED) {
1995 return;
1996 }
1997 }
1998 }
1999 crReturnV;
2000 }
2001 crFinishV;
2002 }
2003
2004 static int ssh_closing(Plug plug, char *error_msg, int error_code,
2005 int calling_back)
2006 {
2007 Ssh ssh = (Ssh) plug;
2008 ssh->state = SSH_STATE_CLOSED;
2009 if (ssh->s) {
2010 sk_close(ssh->s);
2011 ssh->s = NULL;
2012 }
2013 if (error_msg) {
2014 /* A socket error has occurred. */
2015 logevent(error_msg);
2016 connection_fatal(ssh->frontend, error_msg);
2017 } else {
2018 /* Otherwise, the remote side closed the connection normally. */
2019 }
2020 return 0;
2021 }
2022
2023 static int ssh_receive(Plug plug, int urgent, char *data, int len)
2024 {
2025 Ssh ssh = (Ssh) plug;
2026 ssh_gotdata(ssh, (unsigned char *)data, len);
2027 if (ssh->state == SSH_STATE_CLOSED) {
2028 if (ssh->s) {
2029 sk_close(ssh->s);
2030 ssh->s = NULL;
2031 }
2032 return 0;
2033 }
2034 return 1;
2035 }
2036
2037 static void ssh_sent(Plug plug, int bufsize)
2038 {
2039 Ssh ssh = (Ssh) plug;
2040 /*
2041 * If the send backlog on the SSH socket itself clears, we
2042 * should unthrottle the whole world if it was throttled.
2043 */
2044 if (bufsize < SSH_MAX_BACKLOG)
2045 ssh_throttle_all(ssh, 0, bufsize);
2046 }
2047
2048 /*
2049 * Connect to specified host and port.
2050 * Returns an error message, or NULL on success.
2051 * Also places the canonical host name into `realhost'. It must be
2052 * freed by the caller.
2053 */
2054 static char *connect_to_host(Ssh ssh, char *host, int port,
2055 char **realhost, int nodelay)
2056 {
2057 static const struct plug_function_table fn_table = {
2058 ssh_closing,
2059 ssh_receive,
2060 ssh_sent,
2061 NULL
2062 };
2063
2064 SockAddr addr;
2065 char *err;
2066
2067 ssh->savedhost = smalloc(1 + strlen(host));
2068 if (!ssh->savedhost)
2069 fatalbox("Out of memory");
2070 strcpy(ssh->savedhost, host);
2071
2072 if (port < 0)
2073 port = 22; /* default ssh port */
2074 ssh->savedport = port;
2075
2076 /*
2077 * Try to find host.
2078 */
2079 logeventf(ssh, "Looking up host \"%s\"", host);
2080 addr = name_lookup(host, port, realhost, &ssh->cfg);
2081 if ((err = sk_addr_error(addr)) != NULL)
2082 return err;
2083
2084 /*
2085 * Open socket.
2086 */
2087 {
2088 char addrbuf[100];
2089 sk_getaddr(addr, addrbuf, 100);
2090 logeventf(ssh, "Connecting to %s port %d", addrbuf, port);
2091 }
2092 ssh->fn = &fn_table;
2093 ssh->s = new_connection(addr, *realhost, port,
2094 0, 1, nodelay, (Plug) ssh, &ssh->cfg);
2095 if ((err = sk_socket_error(ssh->s)) != NULL) {
2096 ssh->s = NULL;
2097 return err;
2098 }
2099
2100 return NULL;
2101 }
2102
2103 /*
2104 * Throttle or unthrottle the SSH connection.
2105 */
2106 static void ssh1_throttle(Ssh ssh, int adjust)
2107 {
2108 int old_count = ssh->v1_throttle_count;
2109 ssh->v1_throttle_count += adjust;
2110 assert(ssh->v1_throttle_count >= 0);
2111 if (ssh->v1_throttle_count && !old_count) {
2112 sk_set_frozen(ssh->s, 1);
2113 } else if (!ssh->v1_throttle_count && old_count) {
2114 sk_set_frozen(ssh->s, 0);
2115 }
2116 }
2117
2118 /*
2119 * Throttle or unthrottle _all_ local data streams (for when sends
2120 * on the SSH connection itself back up).
2121 */
2122 static void ssh_throttle_all(Ssh ssh, int enable, int bufsize)
2123 {
2124 int i;
2125 struct ssh_channel *c;
2126
2127 if (enable == ssh->throttled_all)
2128 return;
2129 ssh->throttled_all = enable;
2130 ssh->overall_bufsize = bufsize;
2131 if (!ssh->channels)
2132 return;
2133 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
2134 switch (c->type) {
2135 case CHAN_MAINSESSION:
2136 /*
2137 * This is treated separately, outside the switch.
2138 */
2139 break;
2140 case CHAN_X11:
2141 x11_override_throttle(c->u.x11.s, enable);
2142 break;
2143 case CHAN_AGENT:
2144 /* Agent channels require no buffer management. */
2145 break;
2146 case CHAN_SOCKDATA:
2147 pfd_override_throttle(c->u.x11.s, enable);
2148 break;
2149 }
2150 }
2151 }
2152
2153 /*
2154 * Username and password input, abstracted off into routines
2155 * reusable in several places - even between SSH1 and SSH2.
2156 */
2157
2158 /* Set up a username or password input loop on a given buffer. */
2159 static void setup_userpass_input(Ssh ssh, char *buffer, int buflen, int echo)
2160 {
2161 ssh->userpass_input_buffer = buffer;
2162 ssh->userpass_input_buflen = buflen;
2163 ssh->userpass_input_bufpos = 0;
2164 ssh->userpass_input_echo = echo;
2165 }
2166
2167 /*
2168 * Process some terminal data in the course of username/password
2169 * input. Returns >0 for success (line of input returned in
2170 * buffer), <0 for failure (user hit ^C/^D, bomb out and exit), 0
2171 * for inconclusive (keep waiting for more input please).
2172 */
2173 static int process_userpass_input(Ssh ssh, unsigned char *in, int inlen)
2174 {
2175 char c;
2176
2177 while (inlen--) {
2178 switch (c = *in++) {
2179 case 10:
2180 case 13:
2181 ssh->userpass_input_buffer[ssh->userpass_input_bufpos] = 0;
2182 ssh->userpass_input_buffer[ssh->userpass_input_buflen-1] = 0;
2183 return +1;
2184 break;
2185 case 8:
2186 case 127:
2187 if (ssh->userpass_input_bufpos > 0) {
2188 if (ssh->userpass_input_echo)
2189 c_write_str(ssh, "\b \b");
2190 ssh->userpass_input_bufpos--;
2191 }
2192 break;
2193 case 21:
2194 case 27:
2195 while (ssh->userpass_input_bufpos > 0) {
2196 if (ssh->userpass_input_echo)
2197 c_write_str(ssh, "\b \b");
2198 ssh->userpass_input_bufpos--;
2199 }
2200 break;
2201 case 3:
2202 case 4:
2203 return -1;
2204 break;
2205 default:
2206 if (((c >= ' ' && c <= '~') ||
2207 ((unsigned char) c >= 160))
2208 && ssh->userpass_input_bufpos < ssh->userpass_input_buflen-1) {
2209 ssh->userpass_input_buffer[ssh->userpass_input_bufpos++] = c;
2210 if (ssh->userpass_input_echo)
2211 c_write(ssh, &c, 1);
2212 }
2213 break;
2214 }
2215 }
2216 return 0;
2217 }
2218
2219 /*
2220 * Handle the key exchange and user authentication phases.
2221 */
2222 static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
2223 {
2224 int i, j;
2225 unsigned char cookie[8];
2226 struct RSAKey servkey, hostkey;
2227 struct MD5Context md5c;
2228 struct do_ssh1_login_state {
2229 int len;
2230 unsigned char *rsabuf, *keystr1, *keystr2;
2231 unsigned long supported_ciphers_mask, supported_auths_mask;
2232 int tried_publickey, tried_agent;
2233 int tis_auth_refused, ccard_auth_refused;
2234 unsigned char session_id[16];
2235 int cipher_type;
2236 char username[100];
2237 void *publickey_blob;
2238 int publickey_bloblen;
2239 char password[100];
2240 char prompt[200];
2241 int pos;
2242 char c;
2243 int pwpkt_type;
2244 unsigned char request[5], *response, *p;
2245 int responselen;
2246 int keyi, nkeys;
2247 int authed;
2248 struct RSAKey key;
2249 Bignum challenge;
2250 char *commentp;
2251 int commentlen;
2252 };
2253 crState(do_ssh1_login_state);
2254
2255 crBegin(ssh->do_ssh1_login_crstate);
2256
2257 if (!ispkt)
2258 crWaitUntil(ispkt);
2259
2260 if (ssh->pktin.type != SSH1_SMSG_PUBLIC_KEY) {
2261 bombout((ssh,"Public key packet not received"));
2262 crReturn(0);
2263 }
2264
2265 logevent("Received public keys");
2266
2267 memcpy(cookie, ssh->pktin.body, 8);
2268
2269 i = makekey(ssh->pktin.body + 8, &servkey, &s->keystr1, 0);
2270 j = makekey(ssh->pktin.body + 8 + i, &hostkey, &s->keystr2, 0);
2271
2272 /*
2273 * Log the host key fingerprint.
2274 */
2275 {
2276 char logmsg[80];
2277 logevent("Host key fingerprint is:");
2278 strcpy(logmsg, " ");
2279 hostkey.comment = NULL;
2280 rsa_fingerprint(logmsg + strlen(logmsg),
2281 sizeof(logmsg) - strlen(logmsg), &hostkey);
2282 logevent(logmsg);
2283 }
2284
2285 ssh->v1_remote_protoflags = GET_32BIT(ssh->pktin.body + 8 + i + j);
2286 s->supported_ciphers_mask = GET_32BIT(ssh->pktin.body + 12 + i + j);
2287 s->supported_auths_mask = GET_32BIT(ssh->pktin.body + 16 + i + j);
2288
2289 ssh->v1_local_protoflags =
2290 ssh->v1_remote_protoflags & SSH1_PROTOFLAGS_SUPPORTED;
2291 ssh->v1_local_protoflags |= SSH1_PROTOFLAG_SCREEN_NUMBER;
2292
2293 MD5Init(&md5c);
2294 MD5Update(&md5c, s->keystr2, hostkey.bytes);
2295 MD5Update(&md5c, s->keystr1, servkey.bytes);
2296 MD5Update(&md5c, ssh->pktin.body, 8);
2297 MD5Final(s->session_id, &md5c);
2298
2299 for (i = 0; i < 32; i++)
2300 ssh->session_key[i] = random_byte();
2301
2302 s->len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes);
2303
2304 s->rsabuf = smalloc(s->len);
2305 if (!s->rsabuf)
2306 fatalbox("Out of memory");
2307
2308 /*
2309 * Verify the host key.
2310 */
2311 {
2312 /*
2313 * First format the key into a string.
2314 */
2315 int len = rsastr_len(&hostkey);
2316 char fingerprint[100];
2317 char *keystr = smalloc(len);
2318 if (!keystr)
2319 fatalbox("Out of memory");
2320 rsastr_fmt(keystr, &hostkey);
2321 rsa_fingerprint(fingerprint, sizeof(fingerprint), &hostkey);
2322 verify_ssh_host_key(ssh->frontend,
2323 ssh->savedhost, ssh->savedport, "rsa", keystr,
2324 fingerprint);
2325 sfree(keystr);
2326 }
2327
2328 for (i = 0; i < 32; i++) {
2329 s->rsabuf[i] = ssh->session_key[i];
2330 if (i < 16)
2331 s->rsabuf[i] ^= s->session_id[i];
2332 }
2333
2334 if (hostkey.bytes > servkey.bytes) {
2335 rsaencrypt(s->rsabuf, 32, &servkey);
2336 rsaencrypt(s->rsabuf, servkey.bytes, &hostkey);
2337 } else {
2338 rsaencrypt(s->rsabuf, 32, &hostkey);
2339 rsaencrypt(s->rsabuf, hostkey.bytes, &servkey);
2340 }
2341
2342 logevent("Encrypted session key");
2343
2344 {
2345 int cipher_chosen = 0, warn = 0;
2346 char *cipher_string = NULL;
2347 int i;
2348 for (i = 0; !cipher_chosen && i < CIPHER_MAX; i++) {
2349 int next_cipher = ssh->cfg.ssh_cipherlist[i];
2350 if (next_cipher == CIPHER_WARN) {
2351 /* If/when we choose a cipher, warn about it */
2352 warn = 1;
2353 } else if (next_cipher == CIPHER_AES) {
2354 /* XXX Probably don't need to mention this. */
2355 logevent("AES not supported in SSH1, skipping");
2356 } else {
2357 switch (next_cipher) {
2358 case CIPHER_3DES: s->cipher_type = SSH_CIPHER_3DES;
2359 cipher_string = "3DES"; break;
2360 case CIPHER_BLOWFISH: s->cipher_type = SSH_CIPHER_BLOWFISH;
2361 cipher_string = "Blowfish"; break;
2362 case CIPHER_DES: s->cipher_type = SSH_CIPHER_DES;
2363 cipher_string = "single-DES"; break;
2364 }
2365 if (s->supported_ciphers_mask & (1 << s->cipher_type))
2366 cipher_chosen = 1;
2367 }
2368 }
2369 if (!cipher_chosen) {
2370 if ((s->supported_ciphers_mask & (1 << SSH_CIPHER_3DES)) == 0)
2371 bombout((ssh,"Server violates SSH 1 protocol by not "
2372 "supporting 3DES encryption"));
2373 else
2374 /* shouldn't happen */
2375 bombout((ssh,"No supported ciphers found"));
2376 crReturn(0);
2377 }
2378
2379 /* Warn about chosen cipher if necessary. */
2380 if (warn)
2381 askcipher(ssh->frontend, cipher_string, 0);
2382 }
2383
2384 switch (s->cipher_type) {
2385 case SSH_CIPHER_3DES:
2386 logevent("Using 3DES encryption");
2387 break;
2388 case SSH_CIPHER_DES:
2389 logevent("Using single-DES encryption");
2390 break;
2391 case SSH_CIPHER_BLOWFISH:
2392 logevent("Using Blowfish encryption");
2393 break;
2394 }
2395
2396 send_packet(ssh, SSH1_CMSG_SESSION_KEY,
2397 PKT_CHAR, s->cipher_type,
2398 PKT_DATA, cookie, 8,
2399 PKT_CHAR, (s->len * 8) >> 8, PKT_CHAR, (s->len * 8) & 0xFF,
2400 PKT_DATA, s->rsabuf, s->len,
2401 PKT_INT, ssh->v1_local_protoflags, PKT_END);
2402
2403 logevent("Trying to enable encryption...");
2404
2405 sfree(s->rsabuf);
2406
2407 ssh->cipher = (s->cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 :
2408 s->cipher_type == SSH_CIPHER_DES ? &ssh_des :
2409 &ssh_3des);
2410 ssh->v1_cipher_ctx = ssh->cipher->make_context();
2411 ssh->cipher->sesskey(ssh->v1_cipher_ctx, ssh->session_key);
2412 logeventf(ssh, "Initialised %s encryption", ssh->cipher->text_name);
2413
2414 ssh->crcda_ctx = crcda_make_context();
2415 logevent("Installing CRC compensation attack detector");
2416
2417 crWaitUntil(ispkt);
2418
2419 if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
2420 bombout((ssh,"Encryption not successfully enabled"));
2421 crReturn(0);
2422 }
2423
2424 logevent("Successfully started encryption");
2425
2426 fflush(stdout);
2427 {
2428 if ((flags & FLAG_INTERACTIVE) && !*ssh->cfg.username) {
2429 if (ssh_get_line && !ssh_getline_pw_only) {
2430 if (!ssh_get_line("login as: ",
2431 s->username, sizeof(s->username), FALSE)) {
2432 /*
2433 * get_line failed to get a username.
2434 * Terminate.
2435 */
2436 logevent("No username provided. Abandoning session.");
2437 ssh->state = SSH_STATE_CLOSED;
2438 crReturn(1);
2439 }
2440 } else {
2441 int ret; /* need not be kept over crReturn */
2442 c_write_str(ssh, "login as: ");
2443 ssh->send_ok = 1;
2444
2445 setup_userpass_input(ssh, s->username, sizeof(s->username), 1);
2446 do {
2447 crWaitUntil(!ispkt);
2448 ret = process_userpass_input(ssh, in, inlen);
2449 } while (ret == 0);
2450 if (ret < 0)
2451 cleanup_exit(0);
2452 c_write_str(ssh, "\r\n");
2453 }
2454 } else {
2455 strncpy(s->username, ssh->cfg.username, sizeof(s->username));
2456 s->username[sizeof(s->username)-1] = '\0';
2457 }
2458
2459 send_packet(ssh, SSH1_CMSG_USER, PKT_STR, s->username, PKT_END);
2460 {
2461 char userlog[22 + sizeof(s->username)];
2462 sprintf(userlog, "Sent username \"%s\"", s->username);
2463 logevent(userlog);
2464 if (flags & FLAG_INTERACTIVE &&
2465 (!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) {
2466 strcat(userlog, "\r\n");
2467 c_write_str(ssh, userlog);
2468 }
2469 }
2470 }
2471
2472 crWaitUntil(ispkt);
2473
2474 if ((ssh->remote_bugs & BUG_CHOKES_ON_RSA)) {
2475 /* We must not attempt PK auth. Pretend we've already tried it. */
2476 s->tried_publickey = s->tried_agent = 1;
2477 } else {
2478 s->tried_publickey = s->tried_agent = 0;
2479 }
2480 s->tis_auth_refused = s->ccard_auth_refused = 0;
2481 /* Load the public half of ssh->cfg.keyfile so we notice if it's in Pageant */
2482 if (!filename_is_null(ssh->cfg.keyfile)) {
2483 if (!rsakey_pubblob(&ssh->cfg.keyfile,
2484 &s->publickey_blob, &s->publickey_bloblen))
2485 s->publickey_blob = NULL;
2486 } else
2487 s->publickey_blob = NULL;
2488
2489 while (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2490 s->pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
2491
2492 if (agent_exists() && !s->tried_agent) {
2493 /*
2494 * Attempt RSA authentication using Pageant.
2495 */
2496 void *r;
2497
2498 s->authed = FALSE;
2499 s->tried_agent = 1;
2500 logevent("Pageant is running. Requesting keys.");
2501
2502 /* Request the keys held by the agent. */
2503 PUT_32BIT(s->request, 1);
2504 s->request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES;
2505 agent_query(s->request, 5, &r, &s->responselen);
2506 s->response = (unsigned char *) r;
2507 if (s->response && s->responselen >= 5 &&
2508 s->response[4] == SSH1_AGENT_RSA_IDENTITIES_ANSWER) {
2509 s->p = s->response + 5;
2510 s->nkeys = GET_32BIT(s->p);
2511 s->p += 4;
2512 {
2513 char buf[64];
2514 sprintf(buf, "Pageant has %d SSH1 keys", s->nkeys);
2515 logevent(buf);
2516 }
2517 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
2518 {
2519 char buf[64];
2520 sprintf(buf, "Trying Pageant key #%d", s->keyi);
2521 logevent(buf);
2522 }
2523 if (s->publickey_blob &&
2524 !memcmp(s->p, s->publickey_blob,
2525 s->publickey_bloblen)) {
2526 logevent("This key matches configured key file");
2527 s->tried_publickey = 1;
2528 }
2529 s->p += 4;
2530 s->p += ssh1_read_bignum(s->p, &s->key.exponent);
2531 s->p += ssh1_read_bignum(s->p, &s->key.modulus);
2532 s->commentlen = GET_32BIT(s->p);
2533 s->p += 4;
2534 s->commentp = (char *)s->p;
2535 s->p += s->commentlen;
2536 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
2537 PKT_BIGNUM, s->key.modulus, PKT_END);
2538 crWaitUntil(ispkt);
2539 if (ssh->pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
2540 logevent("Key refused");
2541 continue;
2542 }
2543 logevent("Received RSA challenge");
2544 ssh1_read_bignum(ssh->pktin.body, &s->challenge);
2545 {
2546 char *agentreq, *q, *ret;
2547 void *vret;
2548 int len, retlen;
2549 len = 1 + 4; /* message type, bit count */
2550 len += ssh1_bignum_length(s->key.exponent);
2551 len += ssh1_bignum_length(s->key.modulus);
2552 len += ssh1_bignum_length(s->challenge);
2553 len += 16; /* session id */
2554 len += 4; /* response format */
2555 agentreq = smalloc(4 + len);
2556 PUT_32BIT(agentreq, len);
2557 q = agentreq + 4;
2558 *q++ = SSH1_AGENTC_RSA_CHALLENGE;
2559 PUT_32BIT(q, bignum_bitcount(s->key.modulus));
2560 q += 4;
2561 q += ssh1_write_bignum(q, s->key.exponent);
2562 q += ssh1_write_bignum(q, s->key.modulus);
2563 q += ssh1_write_bignum(q, s->challenge);
2564 memcpy(q, s->session_id, 16);
2565 q += 16;
2566 PUT_32BIT(q, 1); /* response format */
2567 agent_query(agentreq, len + 4, &vret, &retlen);
2568 ret = vret;
2569 sfree(agentreq);
2570 if (ret) {
2571 if (ret[4] == SSH1_AGENT_RSA_RESPONSE) {
2572 logevent("Sending Pageant's response");
2573 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
2574 PKT_DATA, ret + 5, 16,
2575 PKT_END);
2576 sfree(ret);
2577 crWaitUntil(ispkt);
2578 if (ssh->pktin.type == SSH1_SMSG_SUCCESS) {
2579 logevent
2580 ("Pageant's response accepted");
2581 if (flags & FLAG_VERBOSE) {
2582 c_write_str(ssh, "Authenticated using"
2583 " RSA key \"");
2584 c_write(ssh, s->commentp,
2585 s->commentlen);
2586 c_write_str(ssh, "\" from agent\r\n");
2587 }
2588 s->authed = TRUE;
2589 } else
2590 logevent
2591 ("Pageant's response not accepted");
2592 } else {
2593 logevent
2594 ("Pageant failed to answer challenge");
2595 sfree(ret);
2596 }
2597 } else {
2598 logevent("No reply received from Pageant");
2599 }
2600 }
2601 freebn(s->key.exponent);
2602 freebn(s->key.modulus);
2603 freebn(s->challenge);
2604 if (s->authed)
2605 break;
2606 }
2607 }
2608 if (s->authed)
2609 break;
2610 }
2611 if (!filename_is_null(ssh->cfg.keyfile) && !s->tried_publickey)
2612 s->pwpkt_type = SSH1_CMSG_AUTH_RSA;
2613
2614 if (ssh->cfg.try_tis_auth &&
2615 (s->supported_auths_mask & (1 << SSH1_AUTH_TIS)) &&
2616 !s->tis_auth_refused) {
2617 s->pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
2618 logevent("Requested TIS authentication");
2619 send_packet(ssh, SSH1_CMSG_AUTH_TIS, PKT_END);
2620 crWaitUntil(ispkt);
2621 if (ssh->pktin.type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
2622 logevent("TIS authentication declined");
2623 if (flags & FLAG_INTERACTIVE)
2624 c_write_str(ssh, "TIS authentication refused.\r\n");
2625 s->tis_auth_refused = 1;
2626 continue;
2627 } else {
2628 int challengelen = GET_32BIT(ssh->pktin.body);
2629 logevent("Received TIS challenge");
2630 if (challengelen > sizeof(s->prompt) - 1)
2631 challengelen = sizeof(s->prompt) - 1;/* prevent overrun */
2632 memcpy(s->prompt, ssh->pktin.body + 4, challengelen);
2633 /* Prompt heuristic comes from OpenSSH */
2634 strncpy(s->prompt + challengelen,
2635 memchr(s->prompt, '\n', challengelen) ?
2636 "": "\r\nResponse: ",
2637 (sizeof s->prompt) - challengelen);
2638 s->prompt[(sizeof s->prompt) - 1] = '\0';
2639 }
2640 }
2641 if (ssh->cfg.try_tis_auth &&
2642 (s->supported_auths_mask & (1 << SSH1_AUTH_CCARD)) &&
2643 !s->ccard_auth_refused) {
2644 s->pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE;
2645 logevent("Requested CryptoCard authentication");
2646 send_packet(ssh, SSH1_CMSG_AUTH_CCARD, PKT_END);
2647 crWaitUntil(ispkt);
2648 if (ssh->pktin.type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
2649 logevent("CryptoCard authentication declined");
2650 c_write_str(ssh, "CryptoCard authentication refused.\r\n");
2651 s->ccard_auth_refused = 1;
2652 continue;
2653 } else {
2654 int challengelen = GET_32BIT(ssh->pktin.body);
2655 logevent("Received CryptoCard challenge");
2656 if (challengelen > sizeof(s->prompt) - 1)
2657 challengelen = sizeof(s->prompt) - 1;/* prevent overrun */
2658 memcpy(s->prompt, ssh->pktin.body + 4, challengelen);
2659 strncpy(s->prompt + challengelen,
2660 memchr(s->prompt, '\n', challengelen) ?
2661 "" : "\r\nResponse: ",
2662 sizeof(s->prompt) - challengelen);
2663 s->prompt[sizeof(s->prompt) - 1] = '\0';
2664 }
2665 }
2666 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
2667 sprintf(s->prompt, "%.90s@%.90s's password: ",
2668 s->username, ssh->savedhost);
2669 }
2670 if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) {
2671 char *comment = NULL;
2672 int type;
2673 char msgbuf[256];
2674 if (flags & FLAG_VERBOSE)
2675 c_write_str(ssh, "Trying public key authentication.\r\n");
2676 logeventf(ssh, "Trying public key \"%s\"",
2677 filename_to_str(&ssh->cfg.keyfile));
2678 type = key_type(&ssh->cfg.keyfile);
2679 if (type != SSH_KEYTYPE_SSH1) {
2680 sprintf(msgbuf, "Key is of wrong type (%s)",
2681 key_type_to_str(type));
2682 logevent(msgbuf);
2683 c_write_str(ssh, msgbuf);
2684 c_write_str(ssh, "\r\n");
2685 s->tried_publickey = 1;
2686 continue;
2687 }
2688 if (!rsakey_encrypted(&ssh->cfg.keyfile, &comment)) {
2689 if (flags & FLAG_VERBOSE)
2690 c_write_str(ssh, "No passphrase required.\r\n");
2691 goto tryauth;
2692 }
2693 sprintf(s->prompt, "Passphrase for key \"%.100s\": ", comment);
2694 sfree(comment);
2695 }
2696
2697 /*
2698 * Show password prompt, having first obtained it via a TIS
2699 * or CryptoCard exchange if we're doing TIS or CryptoCard
2700 * authentication.
2701 */
2702 if (ssh_get_line) {
2703 if (!ssh_get_line(s->prompt, s->password,
2704 sizeof(s->password), TRUE)) {
2705 /*
2706 * get_line failed to get a password (for example
2707 * because one was supplied on the command line
2708 * which has already failed to work). Terminate.
2709 */
2710 send_packet(ssh, SSH1_MSG_DISCONNECT,
2711 PKT_STR, "No more passwords available to try",
2712 PKT_END);
2713 logevent("Unable to authenticate");
2714 connection_fatal(ssh->frontend, "Unable to authenticate");
2715 ssh->state = SSH_STATE_CLOSED;
2716 crReturn(1);
2717 }
2718 } else {
2719 /* Prompt may have come from server. We've munged it a bit, so
2720 * we know it to be zero-terminated at least once. */
2721 int ret; /* need not be saved over crReturn */
2722 c_write_untrusted(ssh, s->prompt, strlen(s->prompt));
2723 s->pos = 0;
2724
2725 setup_userpass_input(ssh, s->password, sizeof(s->password), 0);
2726 do {
2727 crWaitUntil(!ispkt);
2728 ret = process_userpass_input(ssh, in, inlen);
2729 } while (ret == 0);
2730 if (ret < 0)
2731 cleanup_exit(0);
2732 c_write_str(ssh, "\r\n");
2733 }
2734
2735 tryauth:
2736 if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) {
2737 /*
2738 * Try public key authentication with the specified
2739 * key file.
2740 */
2741 s->tried_publickey = 1;
2742
2743 {
2744 int ret = loadrsakey(&ssh->cfg.keyfile, &s->key, s->password);
2745 if (ret == 0) {
2746 c_write_str(ssh, "Couldn't load private key from ");
2747 c_write_str(ssh, filename_to_str(&ssh->cfg.keyfile));
2748 c_write_str(ssh, ".\r\n");
2749 continue; /* go and try password */
2750 }
2751 if (ret == -1) {
2752 c_write_str(ssh, "Wrong passphrase.\r\n");
2753 s->tried_publickey = 0;
2754 continue; /* try again */
2755 }
2756 }
2757
2758 /*
2759 * Send a public key attempt.
2760 */
2761 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
2762 PKT_BIGNUM, s->key.modulus, PKT_END);
2763
2764 crWaitUntil(ispkt);
2765 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2766 c_write_str(ssh, "Server refused our public key.\r\n");
2767 continue; /* go and try password */
2768 }
2769 if (ssh->pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
2770 bombout((ssh,"Bizarre response to offer of public key"));
2771 crReturn(0);
2772 }
2773
2774 {
2775 int i;
2776 unsigned char buffer[32];
2777 Bignum challenge, response;
2778
2779 ssh1_read_bignum(ssh->pktin.body, &challenge);
2780 response = rsadecrypt(challenge, &s->key);
2781 freebn(s->key.private_exponent);/* burn the evidence */
2782
2783 for (i = 0; i < 32; i++) {
2784 buffer[i] = bignum_byte(response, 31 - i);
2785 }
2786
2787 MD5Init(&md5c);
2788 MD5Update(&md5c, buffer, 32);
2789 MD5Update(&md5c, s->session_id, 16);
2790 MD5Final(buffer, &md5c);
2791
2792 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
2793 PKT_DATA, buffer, 16, PKT_END);
2794
2795 freebn(challenge);
2796 freebn(response);
2797 }
2798
2799 crWaitUntil(ispkt);
2800 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2801 if (flags & FLAG_VERBOSE)
2802 c_write_str(ssh, "Failed to authenticate with"
2803 " our public key.\r\n");
2804 continue; /* go and try password */
2805 } else if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
2806 bombout((ssh,"Bizarre response to RSA authentication response"));
2807 crReturn(0);
2808 }
2809
2810 break; /* we're through! */
2811 } else {
2812 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
2813 /*
2814 * Defence against traffic analysis: we send a
2815 * whole bunch of packets containing strings of
2816 * different lengths. One of these strings is the
2817 * password, in a SSH1_CMSG_AUTH_PASSWORD packet.
2818 * The others are all random data in
2819 * SSH1_MSG_IGNORE packets. This way a passive
2820 * listener can't tell which is the password, and
2821 * hence can't deduce the password length.
2822 *
2823 * Anybody with a password length greater than 16
2824 * bytes is going to have enough entropy in their
2825 * password that a listener won't find it _that_
2826 * much help to know how long it is. So what we'll
2827 * do is:
2828 *
2829 * - if password length < 16, we send 15 packets
2830 * containing string lengths 1 through 15
2831 *
2832 * - otherwise, we let N be the nearest multiple
2833 * of 8 below the password length, and send 8
2834 * packets containing string lengths N through
2835 * N+7. This won't obscure the order of
2836 * magnitude of the password length, but it will
2837 * introduce a bit of extra uncertainty.
2838 *
2839 * A few servers (the old 1.2.18 through 1.2.22)
2840 * can't deal with SSH1_MSG_IGNORE. For these
2841 * servers, we need an alternative defence. We make
2842 * use of the fact that the password is interpreted
2843 * as a C string: so we can append a NUL, then some
2844 * random data.
2845 *
2846 * One server (a Cisco one) can deal with neither
2847 * SSH1_MSG_IGNORE _nor_ a padded password string.
2848 * For this server we are left with no defences
2849 * against password length sniffing.
2850 */
2851 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE)) {
2852 /*
2853 * The server can deal with SSH1_MSG_IGNORE, so
2854 * we can use the primary defence.
2855 */
2856 int bottom, top, pwlen, i;
2857 char *randomstr;
2858
2859 pwlen = strlen(s->password);
2860 if (pwlen < 16) {
2861 bottom = 0; /* zero length passwords are OK! :-) */
2862 top = 15;
2863 } else {
2864 bottom = pwlen & ~7;
2865 top = bottom + 7;
2866 }
2867
2868 assert(pwlen >= bottom && pwlen <= top);
2869
2870 randomstr = smalloc(top + 1);
2871
2872 for (i = bottom; i <= top; i++) {
2873 if (i == pwlen)
2874 defer_packet(ssh, s->pwpkt_type,
2875 PKT_STR, s->password, PKT_END);
2876 else {
2877 for (j = 0; j < i; j++) {
2878 do {
2879 randomstr[j] = random_byte();
2880 } while (randomstr[j] == '\0');
2881 }
2882 randomstr[i] = '\0';
2883 defer_packet(ssh, SSH1_MSG_IGNORE,
2884 PKT_STR, randomstr, PKT_END);
2885 }
2886 }
2887 logevent("Sending password with camouflage packets");
2888 ssh_pkt_defersend(ssh);
2889 }
2890 else if (!(ssh->remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) {
2891 /*
2892 * The server can't deal with SSH1_MSG_IGNORE
2893 * but can deal with padded passwords, so we
2894 * can use the secondary defence.
2895 */
2896 char string[64];
2897 char *ss;
2898 int len;
2899
2900 len = strlen(s->password);
2901 if (len < sizeof(string)) {
2902 ss = string;
2903 strcpy(string, s->password);
2904 len++; /* cover the zero byte */
2905 while (len < sizeof(string)) {
2906 string[len++] = (char) random_byte();
2907 }
2908 } else {
2909 ss = s->password;
2910 }
2911 logevent("Sending length-padded password");
2912 send_packet(ssh, s->pwpkt_type, PKT_INT, len,
2913 PKT_DATA, ss, len, PKT_END);
2914 } else {
2915 /*
2916 * The server has _both_
2917 * BUG_CHOKES_ON_SSH1_IGNORE and
2918 * BUG_NEEDS_SSH1_PLAIN_PASSWORD. There is
2919 * therefore nothing we can do.
2920 */
2921 int len;
2922 len = strlen(s->password);
2923 logevent("Sending unpadded password");
2924 send_packet(ssh, s->pwpkt_type, PKT_INT, len,
2925 PKT_DATA, s->password, len, PKT_END);
2926 }
2927 } else {
2928 send_packet(ssh, s->pwpkt_type, PKT_STR, s->password, PKT_END);
2929 }
2930 }
2931 logevent("Sent password");
2932 memset(s->password, 0, strlen(s->password));
2933 crWaitUntil(ispkt);
2934 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2935 if (flags & FLAG_VERBOSE)
2936 c_write_str(ssh, "Access denied\r\n");
2937 logevent("Authentication refused");
2938 } else if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
2939 bombout((ssh,"Strange packet received, type %d", ssh->pktin.type));
2940 crReturn(0);
2941 }
2942 }
2943
2944 logevent("Authentication successful");
2945
2946 crFinish(1);
2947 }
2948
2949 void sshfwd_close(struct ssh_channel *c)
2950 {
2951 Ssh ssh = c->ssh;
2952
2953 if (c && !c->closes) {
2954 /*
2955 * If the channel's remoteid is -1, we have sent
2956 * CHANNEL_OPEN for this channel, but it hasn't even been
2957 * acknowledged by the server. So we must set a close flag
2958 * on it now, and then when the server acks the channel
2959 * open, we can close it then.
2960 */
2961 if (((int)c->remoteid) != -1) {
2962 if (ssh->version == 1) {
2963 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid,
2964 PKT_END);
2965 } else {
2966 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
2967 ssh2_pkt_adduint32(ssh, c->remoteid);
2968 ssh2_pkt_send(ssh);
2969 }
2970 }
2971 c->closes = 1; /* sent MSG_CLOSE */
2972 if (c->type == CHAN_X11) {
2973 c->u.x11.s = NULL;
2974 logevent("Forwarded X11 connection terminated");
2975 } else if (c->type == CHAN_SOCKDATA ||
2976 c->type == CHAN_SOCKDATA_DORMANT) {
2977 c->u.pfd.s = NULL;
2978 logevent("Forwarded port closed");
2979 }
2980 }
2981 }
2982
2983 int sshfwd_write(struct ssh_channel *c, char *buf, int len)
2984 {
2985 Ssh ssh = c->ssh;
2986
2987 if (ssh->version == 1) {
2988 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
2989 PKT_INT, c->remoteid,
2990 PKT_INT, len, PKT_DATA, buf, len, PKT_END);
2991 /*
2992 * In SSH1 we can return 0 here - implying that forwarded
2993 * connections are never individually throttled - because
2994 * the only circumstance that can cause throttling will be
2995 * the whole SSH connection backing up, in which case
2996 * _everything_ will be throttled as a whole.
2997 */
2998 return 0;
2999 } else {
3000 ssh2_add_channel_data(c, buf, len);
3001 return ssh2_try_send(c);
3002 }
3003 }
3004
3005 void sshfwd_unthrottle(struct ssh_channel *c, int bufsize)
3006 {
3007 Ssh ssh = c->ssh;
3008
3009 if (ssh->version == 1) {
3010 if (c->v.v1.throttling && bufsize < SSH1_BUFFER_LIMIT) {
3011 c->v.v1.throttling = 0;
3012 ssh1_throttle(ssh, -1);
3013 }
3014 } else {
3015 ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
3016 }
3017 }
3018
3019 static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
3020 {
3021 crBegin(ssh->ssh1_protocol_crstate);
3022
3023 random_init();
3024
3025 while (!do_ssh1_login(ssh, in, inlen, ispkt)) {
3026 crReturnV;
3027 }
3028 if (ssh->state == SSH_STATE_CLOSED)
3029 crReturnV;
3030
3031 if (ssh->cfg.agentfwd && agent_exists()) {
3032 logevent("Requesting agent forwarding");
3033 send_packet(ssh, SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END);
3034 do {
3035 crReturnV;
3036 } while (!ispkt);
3037 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3038 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3039 bombout((ssh,"Protocol confusion"));
3040 crReturnV;
3041 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3042 logevent("Agent forwarding refused");
3043 } else {
3044 logevent("Agent forwarding enabled");
3045 ssh->agentfwd_enabled = TRUE;
3046 }
3047 }
3048
3049 if (ssh->cfg.x11_forward) {
3050 char proto[20], data[64];
3051 logevent("Requesting X11 forwarding");
3052 ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
3053 data, sizeof(data), ssh->cfg.x11_auth);
3054 x11_get_real_auth(ssh->x11auth, ssh->cfg.x11_display);
3055 if (ssh->v1_local_protoflags & SSH1_PROTOFLAG_SCREEN_NUMBER) {
3056 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
3057 PKT_STR, proto, PKT_STR, data,
3058 PKT_INT, x11_get_screen_number(ssh->cfg.x11_display),
3059 PKT_END);
3060 } else {
3061 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
3062 PKT_STR, proto, PKT_STR, data, PKT_END);
3063 }
3064 do {
3065 crReturnV;
3066 } while (!ispkt);
3067 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3068 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3069 bombout((ssh,"Protocol confusion"));
3070 crReturnV;
3071 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3072 logevent("X11 forwarding refused");
3073 } else {
3074 logevent("X11 forwarding enabled");
3075 ssh->X11_fwd_enabled = TRUE;
3076 }
3077 }
3078
3079 {
3080 char type;
3081 int n;
3082 int sport,dport,sserv,dserv;
3083 char sports[256], dports[256], saddr[256], host[256];
3084
3085 ssh->rportfwds = newtree234(ssh_rportcmp_ssh1);
3086 /* Add port forwardings. */
3087 ssh->portfwd_strptr = ssh->cfg.portfwd;
3088 while (*ssh->portfwd_strptr) {
3089 type = *ssh->portfwd_strptr++;
3090 saddr[0] = '\0';
3091 n = 0;
3092 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != '\t') {
3093 if (*ssh->portfwd_strptr == ':') {
3094 /*
3095 * We've seen a colon in the middle of the
3096 * source port number. This means that
3097 * everything we've seen until now is the
3098 * source _address_, so we'll move it into
3099 * saddr and start sports from the beginning
3100 * again.
3101 */
3102 ssh->portfwd_strptr++;
3103 sports[n] = '\0';
3104 strcpy(saddr, sports);
3105 n = 0;
3106 }
3107 if (n < 255) sports[n++] = *ssh->portfwd_strptr++;
3108 }
3109 sports[n] = 0;
3110 if (*ssh->portfwd_strptr == '\t')
3111 ssh->portfwd_strptr++;
3112 n = 0;
3113 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':') {
3114 if (n < 255) host[n++] = *ssh->portfwd_strptr++;
3115 }
3116 host[n] = 0;
3117 if (*ssh->portfwd_strptr == ':')
3118 ssh->portfwd_strptr++;
3119 n = 0;
3120 while (*ssh->portfwd_strptr) {
3121 if (n < 255) dports[n++] = *ssh->portfwd_strptr++;
3122 }
3123 dports[n] = 0;
3124 ssh->portfwd_strptr++;
3125 dport = atoi(dports);
3126 dserv = 0;
3127 if (dport == 0) {
3128 dserv = 1;
3129 dport = net_service_lookup(dports);
3130 if (!dport) {
3131 logeventf(ssh, "Service lookup failed for"
3132 " destination port \"%s\"", dports);
3133 }
3134 }
3135 sport = atoi(sports);
3136 sserv = 0;
3137 if (sport == 0) {
3138 sserv = 1;
3139 sport = net_service_lookup(sports);
3140 if (!sport) {
3141 logeventf(ssh, "Service lookup failed for source"
3142 " port \"%s\"", sports);
3143 }
3144 }
3145 if (sport && dport) {
3146 if (type == 'L') {
3147 pfd_addforward(host, dport, *saddr ? saddr : NULL,
3148 sport, ssh, &ssh->cfg);
3149 logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
3150 " forwarding to %s:%.*s%.*s%d%.*s",
3151 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
3152 (int)(*saddr?1:0), ":",
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 } else {
3159 struct ssh_rportfwd *pf;
3160 pf = smalloc(sizeof(*pf));
3161 strcpy(pf->dhost, host);
3162 pf->dport = dport;
3163 if (saddr) {
3164 logeventf(ssh,
3165 "SSH1 cannot handle source address spec \"%s:%d\"; ignoring",
3166 saddr, sport);
3167 }
3168 if (add234(ssh->rportfwds, pf) != pf) {
3169 logeventf(ssh,
3170 "Duplicate remote port forwarding to %s:%d",
3171 host, dport);
3172 sfree(pf);
3173 } else {
3174 logeventf(ssh, "Requesting remote port %.*s%.*s%d%.*s"
3175 " forward to %s:%.*s%.*s%d%.*s",
3176 (int)(sserv ? strlen(sports) : 0), sports,
3177 sserv, "(", sport, sserv, ")",
3178 host,
3179 (int)(dserv ? strlen(dports) : 0), dports,
3180 dserv, "(", dport, dserv, ")");
3181 send_packet(ssh, SSH1_CMSG_PORT_FORWARD_REQUEST,
3182 PKT_INT, sport,
3183 PKT_STR, host,
3184 PKT_INT, dport,
3185 PKT_END);
3186 do {
3187 crReturnV;
3188 } while (!ispkt);
3189 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3190 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3191 bombout((ssh,"Protocol confusion"));
3192 crReturnV;
3193 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3194 c_write_str(ssh, "Server refused port"
3195 " forwarding\r\n");
3196 }
3197 logevent("Remote port forwarding enabled");
3198 }
3199 }
3200 }
3201 }
3202 }
3203
3204 if (!ssh->cfg.nopty) {
3205 send_packet(ssh, SSH1_CMSG_REQUEST_PTY,
3206 PKT_STR, ssh->cfg.termtype,
3207 PKT_INT, ssh->term_height,
3208 PKT_INT, ssh->term_width,
3209 PKT_INT, 0, PKT_INT, 0, PKT_CHAR, 0, PKT_END);
3210 ssh->state = SSH_STATE_INTERMED;
3211 do {
3212 crReturnV;
3213 } while (!ispkt);
3214 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3215 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3216 bombout((ssh,"Protocol confusion"));
3217 crReturnV;
3218 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3219 c_write_str(ssh, "Server refused to allocate pty\r\n");
3220 ssh->editing = ssh->echoing = 1;
3221 }
3222 logevent("Allocated pty");
3223 } else {
3224 ssh->editing = ssh->echoing = 1;
3225 }
3226
3227 if (ssh->cfg.compression) {
3228 send_packet(ssh, SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END);
3229 do {
3230 crReturnV;
3231 } while (!ispkt);
3232 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3233 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3234 bombout((ssh,"Protocol confusion"));
3235 crReturnV;
3236 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3237 c_write_str(ssh, "Server refused to compress\r\n");
3238 }
3239 logevent("Started compression");
3240 ssh->v1_compressing = TRUE;
3241 ssh->cs_comp_ctx = zlib_compress_init();
3242 logevent("Initialised zlib (RFC1950) compression");
3243 ssh->sc_comp_ctx = zlib_decompress_init();
3244 logevent("Initialised zlib (RFC1950) decompression");
3245 }
3246
3247 /*
3248 * Start the shell or command.
3249 *
3250 * Special case: if the first-choice command is an SSH2
3251 * subsystem (hence not usable here) and the second choice
3252 * exists, we fall straight back to that.
3253 */
3254 {
3255 char *cmd = ssh->cfg.remote_cmd_ptr;
3256
3257 if (ssh->cfg.ssh_subsys && ssh->cfg.remote_cmd_ptr2) {
3258 cmd = ssh->cfg.remote_cmd_ptr2;
3259 ssh->fallback_cmd = TRUE;
3260 }
3261 if (*cmd)
3262 send_packet(ssh, SSH1_CMSG_EXEC_CMD, PKT_STR, cmd, PKT_END);
3263 else
3264 send_packet(ssh, SSH1_CMSG_EXEC_SHELL, PKT_END);
3265 logevent("Started session");
3266 }
3267
3268 ssh->state = SSH_STATE_SESSION;
3269 if (ssh->size_needed)
3270 ssh_size(ssh, ssh->term_width, ssh->term_height);
3271 if (ssh->eof_needed)
3272 ssh_special(ssh, TS_EOF);
3273
3274 if (ssh->ldisc)
3275 ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */
3276 ssh->send_ok = 1;
3277 ssh->channels = newtree234(ssh_channelcmp);
3278 while (1) {
3279 crReturnV;
3280 if (ispkt) {
3281 if (ssh->pktin.type == SSH1_SMSG_STDOUT_DATA ||
3282 ssh->pktin.type == SSH1_SMSG_STDERR_DATA) {
3283 long len = GET_32BIT(ssh->pktin.body);
3284 int bufsize =
3285 from_backend(ssh->frontend,
3286 ssh->pktin.type == SSH1_SMSG_STDERR_DATA,
3287 (char *)(ssh->pktin.body) + 4, len);
3288 if (!ssh->v1_stdout_throttling && bufsize > SSH1_BUFFER_LIMIT) {
3289 ssh->v1_stdout_throttling = 1;
3290 ssh1_throttle(ssh, +1);
3291 }
3292 } else if (ssh->pktin.type == SSH1_MSG_DISCONNECT) {
3293 ssh->state = SSH_STATE_CLOSED;
3294 logevent("Received disconnect request");
3295 crReturnV;
3296 } else if (ssh->pktin.type == SSH1_SMSG_X11_OPEN) {
3297 /* Remote side is trying to open a channel to talk to our
3298 * X-Server. Give them back a local channel number. */
3299 struct ssh_channel *c;
3300
3301 logevent("Received X11 connect request");
3302 /* Refuse if X11 forwarding is disabled. */
3303 if (!ssh->X11_fwd_enabled) {
3304 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3305 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
3306 logevent("Rejected X11 connect request");
3307 } else {
3308 c = smalloc(sizeof(struct ssh_channel));
3309 c->ssh = ssh;
3310
3311 if (x11_init(&c->u.x11.s, ssh->cfg.x11_display, c,
3312 ssh->x11auth, NULL, -1, &ssh->cfg) != NULL) {
3313 logevent("opening X11 forward connection failed");
3314 sfree(c);
3315 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3316 PKT_INT, GET_32BIT(ssh->pktin.body),
3317 PKT_END);
3318 } else {
3319 logevent
3320 ("opening X11 forward connection succeeded");
3321 c->remoteid = GET_32BIT(ssh->pktin.body);
3322 c->localid = alloc_channel_id(ssh);
3323 c->closes = 0;
3324 c->v.v1.throttling = 0;
3325 c->type = CHAN_X11; /* identify channel type */
3326 add234(ssh->channels, c);
3327 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3328 PKT_INT, c->remoteid, PKT_INT,
3329 c->localid, PKT_END);
3330 logevent("Opened X11 forward channel");
3331 }
3332 }
3333 } else if (ssh->pktin.type == SSH1_SMSG_AGENT_OPEN) {
3334 /* Remote side is trying to open a channel to talk to our
3335 * agent. Give them back a local channel number. */
3336 struct ssh_channel *c;
3337
3338 /* Refuse if agent forwarding is disabled. */
3339 if (!ssh->agentfwd_enabled) {
3340 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3341 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
3342 } else {
3343 c = smalloc(sizeof(struct ssh_channel));
3344 c->ssh = ssh;
3345 c->remoteid = GET_32BIT(ssh->pktin.body);
3346 c->localid = alloc_channel_id(ssh);
3347 c->closes = 0;
3348 c->v.v1.throttling = 0;
3349 c->type = CHAN_AGENT; /* identify channel type */
3350 c->u.a.lensofar = 0;
3351 add234(ssh->channels, c);
3352 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3353 PKT_INT, c->remoteid, PKT_INT, c->localid,
3354 PKT_END);
3355 }
3356 } else if (ssh->pktin.type == SSH1_MSG_PORT_OPEN) {
3357 /* Remote side is trying to open a channel to talk to a
3358 * forwarded port. Give them back a local channel number. */
3359 struct ssh_channel *c;
3360 struct ssh_rportfwd pf;
3361 int hostsize, port;
3362 char host[256], buf[1024];
3363 char *p, *h, *e;
3364 c = smalloc(sizeof(struct ssh_channel));
3365 c->ssh = ssh;
3366
3367 hostsize = GET_32BIT(ssh->pktin.body+4);
3368 for (h = host, p = (char *)(ssh->pktin.body+8);
3369 hostsize != 0; hostsize--) {
3370 if (h+1 < host+sizeof(host))
3371 *h++ = *p;
3372 p++;
3373 }
3374 *h = 0;
3375 port = GET_32BIT(p);
3376
3377 strcpy(pf.dhost, host);
3378 pf.dport = port;
3379
3380 if (find234(ssh->rportfwds, &pf, NULL) == NULL) {
3381 sprintf(buf, "Rejected remote port open request for %s:%d",
3382 host, port);
3383 logevent(buf);
3384 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3385 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
3386 } else {
3387 sprintf(buf, "Received remote port open request for %s:%d",
3388 host, port);
3389 logevent(buf);
3390 e = pfd_newconnect(&c->u.pfd.s, host, port, c, &ssh->cfg);
3391 if (e != NULL) {
3392 char buf[256];
3393 sprintf(buf, "Port open failed: %s", e);
3394 logevent(buf);
3395 sfree(c);
3396 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3397 PKT_INT, GET_32BIT(ssh->pktin.body),
3398 PKT_END);
3399 } else {
3400 c->remoteid = GET_32BIT(ssh->pktin.body);
3401 c->localid = alloc_channel_id(ssh);
3402 c->closes = 0;
3403 c->v.v1.throttling = 0;
3404 c->type = CHAN_SOCKDATA; /* identify channel type */
3405 add234(ssh->channels, c);
3406 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3407 PKT_INT, c->remoteid, PKT_INT,
3408 c->localid, PKT_END);
3409 logevent("Forwarded port opened successfully");
3410 }
3411 }
3412
3413 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_OPEN_CONFIRMATION) {
3414 unsigned int remoteid = GET_32BIT(ssh->pktin.body);
3415 unsigned int localid = GET_32BIT(ssh->pktin.body+4);
3416 struct ssh_channel *c;
3417
3418 c = find234(ssh->channels, &remoteid, ssh_channelfind);
3419 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
3420 c->remoteid = localid;
3421 c->type = CHAN_SOCKDATA;
3422 c->v.v1.throttling = 0;
3423 pfd_confirm(c->u.pfd.s);
3424 }
3425
3426 if (c && c->closes) {
3427 /*
3428 * We have a pending close on this channel,
3429 * which we decided on before the server acked
3430 * the channel open. So now we know the
3431 * remoteid, we can close it again.
3432 */
3433 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE,
3434 PKT_INT, c->remoteid, PKT_END);
3435 }
3436
3437 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_OPEN_FAILURE) {
3438 unsigned int remoteid = GET_32BIT(ssh->pktin.body);
3439 struct ssh_channel *c;
3440
3441 c = find234(ssh->channels, &remoteid, ssh_channelfind);
3442 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
3443 logevent("Forwarded connection refused by server");
3444 pfd_close(c->u.pfd.s);
3445 del234(ssh->channels, c);
3446 sfree(c);
3447 }
3448
3449 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ||
3450 ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION) {
3451 /* Remote side closes a channel. */
3452 unsigned i = GET_32BIT(ssh->pktin.body);
3453 struct ssh_channel *c;
3454 c = find234(ssh->channels, &i, ssh_channelfind);
3455 if (c && ((int)c->remoteid) != -1) {
3456 int closetype;
3457 closetype =
3458 (ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ? 1 : 2);
3459
3460 if ((c->closes == 0) && (c->type == CHAN_X11)) {
3461 logevent("Forwarded X11 connection terminated");
3462 assert(c->u.x11.s != NULL);
3463 x11_close(c->u.x11.s);
3464 c->u.x11.s = NULL;
3465 }
3466 if ((c->closes == 0) && (c->type == CHAN_SOCKDATA)) {
3467 logevent("Forwarded port closed");
3468 assert(c->u.pfd.s != NULL);
3469 pfd_close(c->u.pfd.s);
3470 c->u.pfd.s = NULL;
3471 }
3472
3473 c->closes |= (closetype << 2); /* seen this message */
3474 if (!(c->closes & closetype)) {
3475 send_packet(ssh, ssh->pktin.type, PKT_INT, c->remoteid,
3476 PKT_END);
3477 c->closes |= closetype; /* sent it too */
3478 }
3479
3480 if (c->closes == 15) {
3481 del234(ssh->channels, c);
3482 sfree(c);
3483 }
3484 } else {
3485 bombout((ssh,"Received CHANNEL_CLOSE%s for %s channel %d\n",
3486 ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ? "" :
3487 "_CONFIRMATION", c ? "half-open" : "nonexistent",
3488 i));
3489 }
3490 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_DATA) {
3491 /* Data sent down one of our channels. */
3492 int i = GET_32BIT(ssh->pktin.body);
3493 int len = GET_32BIT(ssh->pktin.body + 4);
3494 unsigned char *p = ssh->pktin.body + 8;
3495 struct ssh_channel *c;
3496 c = find234(ssh->channels, &i, ssh_channelfind);
3497 if (c) {
3498 int bufsize;
3499 switch (c->type) {
3500 case CHAN_X11:
3501 bufsize = x11_send(c->u.x11.s, (char *)p, len);
3502 break;
3503 case CHAN_SOCKDATA:
3504 bufsize = pfd_send(c->u.pfd.s, (char *)p, len);
3505 break;
3506 case CHAN_AGENT:
3507 /* Data for an agent message. Buffer it. */
3508 while (len > 0) {
3509 if (c->u.a.lensofar < 4) {
3510 int l = min(4 - c->u.a.lensofar, len);
3511 memcpy(c->u.a.msglen + c->u.a.lensofar, p,
3512 l);
3513 p += l;
3514 len -= l;
3515 c->u.a.lensofar += l;
3516 }
3517 if (c->u.a.lensofar == 4) {
3518 c->u.a.totallen =
3519 4 + GET_32BIT(c->u.a.msglen);
3520 c->u.a.message = smalloc(c->u.a.totallen);
3521 memcpy(c->u.a.message, c->u.a.msglen, 4);
3522 }
3523 if (c->u.a.lensofar >= 4 && len > 0) {
3524 int l =
3525 min(c->u.a.totallen - c->u.a.lensofar,
3526 len);
3527 memcpy(c->u.a.message + c->u.a.lensofar, p,
3528 l);
3529 p += l;
3530 len -= l;
3531 c->u.a.lensofar += l;
3532 }
3533 if (c->u.a.lensofar == c->u.a.totallen) {
3534 void *reply, *sentreply;
3535 int replylen;
3536 agent_query(c->u.a.message,
3537 c->u.a.totallen, &reply,
3538 &replylen);
3539 if (reply)
3540 sentreply = reply;
3541 else {
3542 /* Fake SSH_AGENT_FAILURE. */
3543 sentreply = "\0\0\0\1\5";
3544 replylen = 5;
3545 }
3546 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
3547 PKT_INT, c->remoteid,
3548 PKT_INT, replylen,
3549 PKT_DATA, sentreply, replylen,
3550 PKT_END);
3551 if (reply)
3552 sfree(reply);
3553 sfree(c->u.a.message);
3554 c->u.a.lensofar = 0;
3555 }
3556 }
3557 bufsize = 0; /* agent channels never back up */
3558 break;
3559 }
3560 if (!c->v.v1.throttling && bufsize > SSH1_BUFFER_LIMIT) {
3561 c->v.v1.throttling = 1;
3562 ssh1_throttle(ssh, +1);
3563 }
3564 }
3565 } else if (ssh->pktin.type == SSH1_SMSG_SUCCESS) {
3566 /* may be from EXEC_SHELL on some servers */
3567 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3568 /* may be from EXEC_SHELL on some servers
3569 * if no pty is available or in other odd cases. Ignore */
3570 } else if (ssh->pktin.type == SSH1_SMSG_EXIT_STATUS) {
3571 char buf[100];
3572 ssh->exitcode = GET_32BIT(ssh->pktin.body);
3573 sprintf(buf, "Server sent command exit status %d",
3574 ssh->exitcode);
3575 logevent(buf);
3576 send_packet(ssh, SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
3577 /*
3578 * In case `helpful' firewalls or proxies tack
3579 * extra human-readable text on the end of the
3580 * session which we might mistake for another
3581 * encrypted packet, we close the session once
3582 * we've sent EXIT_CONFIRMATION.
3583 */
3584 ssh->state = SSH_STATE_CLOSED;
3585 crReturnV;
3586 } else {
3587 bombout((ssh,"Strange packet received: type %d", ssh->pktin.type));
3588 crReturnV;
3589 }
3590 } else {
3591 while (inlen > 0) {
3592 int len = min(inlen, 512);
3593 send_packet(ssh, SSH1_CMSG_STDIN_DATA,
3594 PKT_INT, len, PKT_DATA, in, len, PKT_END);
3595 in += len;
3596 inlen -= len;
3597 }
3598 }
3599 }
3600
3601 crFinishV;
3602 }
3603
3604 /*
3605 * Utility routine for decoding comma-separated strings in KEXINIT.
3606 */
3607 static int in_commasep_string(char *needle, char *haystack, int haylen)
3608 {
3609 int needlen;
3610 if (!needle || !haystack) /* protect against null pointers */
3611 return 0;
3612 needlen = strlen(needle);
3613 while (1) {
3614 /*
3615 * Is it at the start of the string?
3616 */
3617 if (haylen >= needlen && /* haystack is long enough */
3618 !memcmp(needle, haystack, needlen) && /* initial match */
3619 (haylen == needlen || haystack[needlen] == ',')
3620 /* either , or EOS follows */
3621 )
3622 return 1;
3623 /*
3624 * If not, search for the next comma and resume after that.
3625 * If no comma found, terminate.
3626 */
3627 while (haylen > 0 && *haystack != ',')
3628 haylen--, haystack++;
3629 if (haylen == 0)
3630 return 0;
3631 haylen--, haystack++; /* skip over comma itself */
3632 }
3633 }
3634
3635 /*
3636 * SSH2 key creation method.
3637 */
3638 static void ssh2_mkkey(Ssh ssh, Bignum K, unsigned char *H,
3639 unsigned char *sessid, char chr,
3640 unsigned char *keyspace)
3641 {
3642 SHA_State s;
3643 /* First 20 bytes. */
3644 SHA_Init(&s);
3645 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
3646 sha_mpint(&s, K);
3647 SHA_Bytes(&s, H, 20);
3648 SHA_Bytes(&s, &chr, 1);
3649 SHA_Bytes(&s, sessid, 20);
3650 SHA_Final(&s, keyspace);
3651 /* Next 20 bytes. */
3652 SHA_Init(&s);
3653 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
3654 sha_mpint(&s, K);
3655 SHA_Bytes(&s, H, 20);
3656 SHA_Bytes(&s, keyspace, 20);
3657 SHA_Final(&s, keyspace + 20);
3658 }
3659
3660 /*
3661 * Handle the SSH2 transport layer.
3662 */
3663 static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
3664 {
3665 struct do_ssh2_transport_state {
3666 int nbits, pbits, warn;
3667 Bignum p, g, e, f, K;
3668 int kex_init_value, kex_reply_value;
3669 const struct ssh_mac **maclist;
3670 int nmacs;
3671 const struct ssh2_cipher *cscipher_tobe;
3672 const struct ssh2_cipher *sccipher_tobe;
3673 const struct ssh_mac *csmac_tobe;
3674 const struct ssh_mac *scmac_tobe;
3675 const struct ssh_compress *cscomp_tobe;
3676 const struct ssh_compress *sccomp_tobe;
3677 char *hostkeydata, *sigdata, *keystr, *fingerprint;
3678 int hostkeylen, siglen;
3679 void *hkey; /* actual host key */
3680 unsigned char exchange_hash[20];
3681 int n_preferred_ciphers;
3682 const struct ssh2_ciphers *preferred_ciphers[CIPHER_MAX];
3683 const struct ssh_compress *preferred_comp;
3684 int first_kex;
3685 };
3686 crState(do_ssh2_transport_state);
3687
3688 crBegin(ssh->do_ssh2_transport_crstate);
3689
3690 s->cscipher_tobe = s->sccipher_tobe = NULL;
3691 s->csmac_tobe = s->scmac_tobe = NULL;
3692 s->cscomp_tobe = s->sccomp_tobe = NULL;
3693
3694 random_init();
3695 s->first_kex = 1;
3696
3697 {
3698 int i;
3699 /*
3700 * Set up the preferred ciphers. (NULL => warn below here)
3701 */
3702 s->n_preferred_ciphers = 0;
3703 for (i = 0; i < CIPHER_MAX; i++) {
3704 switch (ssh->cfg.ssh_cipherlist[i]) {
3705 case CIPHER_BLOWFISH:
3706 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_blowfish;
3707 break;
3708 case CIPHER_DES:
3709 if (ssh->cfg.ssh2_des_cbc) {
3710 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_des;
3711 }
3712 break;
3713 case CIPHER_3DES:
3714 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_3des;
3715 break;
3716 case CIPHER_AES:
3717 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_aes;
3718 break;
3719 case CIPHER_WARN:
3720 /* Flag for later. Don't bother if it's the last in
3721 * the list. */
3722 if (i < CIPHER_MAX - 1) {
3723 s->preferred_ciphers[s->n_preferred_ciphers++] = NULL;
3724 }
3725 break;
3726 }
3727 }
3728 }
3729
3730 /*
3731 * Set up preferred compression.
3732 */
3733 if (ssh->cfg.compression)
3734 s->preferred_comp = &ssh_zlib;
3735 else
3736 s->preferred_comp = &ssh_comp_none;
3737
3738 /*
3739 * Be prepared to work around the buggy MAC problem.
3740 */
3741 if (ssh->remote_bugs & BUG_SSH2_HMAC)
3742 s->maclist = buggymacs, s->nmacs = lenof(buggymacs);
3743 else
3744 s->maclist = macs, s->nmacs = lenof(macs);
3745
3746 begin_key_exchange:
3747 {
3748 int i, j, cipherstr_started;
3749
3750 /*
3751 * Construct and send our key exchange packet.
3752 */
3753 ssh2_pkt_init(ssh, SSH2_MSG_KEXINIT);
3754 for (i = 0; i < 16; i++)
3755 ssh2_pkt_addbyte(ssh, (unsigned char) random_byte());
3756 /* List key exchange algorithms. */
3757 ssh2_pkt_addstring_start(ssh);
3758 for (i = 0; i < lenof(kex_algs); i++) {
3759 if (kex_algs[i] == &ssh_diffiehellman_gex &&
3760 (ssh->remote_bugs & BUG_SSH2_DH_GEX))
3761 continue;
3762 ssh2_pkt_addstring_str(ssh, kex_algs[i]->name);
3763 if (i < lenof(kex_algs) - 1)
3764 ssh2_pkt_addstring_str(ssh, ",");
3765 }
3766 /* List server host key algorithms. */
3767 ssh2_pkt_addstring_start(ssh);
3768 for (i = 0; i < lenof(hostkey_algs); i++) {
3769 ssh2_pkt_addstring_str(ssh, hostkey_algs[i]->name);
3770 if (i < lenof(hostkey_algs) - 1)
3771 ssh2_pkt_addstring_str(ssh, ",");
3772 }
3773 /* List client->server encryption algorithms. */
3774 ssh2_pkt_addstring_start(ssh);
3775 cipherstr_started = 0;
3776 for (i = 0; i < s->n_preferred_ciphers; i++) {
3777 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3778 if (!c) continue; /* warning flag */
3779 for (j = 0; j < c->nciphers; j++) {
3780 if (cipherstr_started)
3781 ssh2_pkt_addstring_str(ssh, ",");
3782 ssh2_pkt_addstring_str(ssh, c->list[j]->name);
3783 cipherstr_started = 1;
3784 }
3785 }
3786 /* List server->client encryption algorithms. */
3787 ssh2_pkt_addstring_start(ssh);
3788 cipherstr_started = 0;
3789 for (i = 0; i < s->n_preferred_ciphers; i++) {
3790 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3791 if (!c) continue; /* warning flag */
3792 for (j = 0; j < c->nciphers; j++) {
3793 if (cipherstr_started)
3794 ssh2_pkt_addstring_str(ssh, ",");
3795 ssh2_pkt_addstring_str(ssh, c->list[j]->name);
3796 cipherstr_started = 1;
3797 }
3798 }
3799 /* List client->server MAC algorithms. */
3800 ssh2_pkt_addstring_start(ssh);
3801 for (i = 0; i < s->nmacs; i++) {
3802 ssh2_pkt_addstring_str(ssh, s->maclist[i]->name);
3803 if (i < s->nmacs - 1)
3804 ssh2_pkt_addstring_str(ssh, ",");
3805 }
3806 /* List server->client MAC algorithms. */
3807 ssh2_pkt_addstring_start(ssh);
3808 for (i = 0; i < s->nmacs; i++) {
3809 ssh2_pkt_addstring_str(ssh, s->maclist[i]->name);
3810 if (i < s->nmacs - 1)
3811 ssh2_pkt_addstring_str(ssh, ",");
3812 }
3813 /* List client->server compression algorithms. */
3814 ssh2_pkt_addstring_start(ssh);
3815 for (i = 0; i < lenof(compressions) + 1; i++) {
3816 const struct ssh_compress *c =
3817 i == 0 ? s->preferred_comp : compressions[i - 1];
3818 ssh2_pkt_addstring_str(ssh, c->name);
3819 if (i < lenof(compressions))
3820 ssh2_pkt_addstring_str(ssh, ",");
3821 }
3822 /* List server->client compression algorithms. */
3823 ssh2_pkt_addstring_start(ssh);
3824 for (i = 0; i < lenof(compressions) + 1; i++) {
3825 const struct ssh_compress *c =
3826 i == 0 ? s->preferred_comp : compressions[i - 1];
3827 ssh2_pkt_addstring_str(ssh, c->name);
3828 if (i < lenof(compressions))
3829 ssh2_pkt_addstring_str(ssh, ",");
3830 }
3831 /* List client->server languages. Empty list. */
3832 ssh2_pkt_addstring_start(ssh);
3833 /* List server->client languages. Empty list. */
3834 ssh2_pkt_addstring_start(ssh);
3835 /* First KEX packet does _not_ follow, because we're not that brave. */
3836 ssh2_pkt_addbool(ssh, FALSE);
3837 /* Reserved. */
3838 ssh2_pkt_adduint32(ssh, 0);
3839 }
3840
3841 ssh->exhash = ssh->exhashbase;
3842 sha_string(&ssh->exhash, ssh->pktout.data + 5, ssh->pktout.length - 5);
3843
3844 ssh2_pkt_send(ssh);
3845
3846 if (!ispkt)
3847 crWaitUntil(ispkt);
3848 if (ssh->pktin.length > 5)
3849 sha_string(&ssh->exhash, ssh->pktin.data + 5, ssh->pktin.length - 5);
3850
3851 /*
3852 * Now examine the other side's KEXINIT to see what we're up
3853 * to.
3854 */
3855 {
3856 char *str;
3857 int i, j, len;
3858
3859 if (ssh->pktin.type != SSH2_MSG_KEXINIT) {
3860 bombout((ssh,"expected key exchange packet from server"));
3861 crReturn(0);
3862 }
3863 ssh->kex = NULL;
3864 ssh->hostkey = NULL;
3865 s->cscipher_tobe = NULL;
3866 s->sccipher_tobe = NULL;
3867 s->csmac_tobe = NULL;
3868 s->scmac_tobe = NULL;
3869 s->cscomp_tobe = NULL;
3870 s->sccomp_tobe = NULL;
3871 ssh->pktin.savedpos += 16; /* skip garbage cookie */
3872 ssh2_pkt_getstring(ssh, &str, &len); /* key exchange algorithms */
3873 for (i = 0; i < lenof(kex_algs); i++) {
3874 if (kex_algs[i] == &ssh_diffiehellman_gex &&
3875 (ssh->remote_bugs & BUG_SSH2_DH_GEX))
3876 continue;
3877 if (in_commasep_string(kex_algs[i]->name, str, len)) {
3878 ssh->kex = kex_algs[i];
3879 break;
3880 }
3881 }
3882 ssh2_pkt_getstring(ssh, &str, &len); /* host key algorithms */
3883 for (i = 0; i < lenof(hostkey_algs); i++) {
3884 if (in_commasep_string(hostkey_algs[i]->name, str, len)) {
3885 ssh->hostkey = hostkey_algs[i];
3886 break;
3887 }
3888 }
3889 ssh2_pkt_getstring(ssh, &str, &len); /* client->server cipher */
3890 s->warn = 0;
3891 for (i = 0; i < s->n_preferred_ciphers; i++) {
3892 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3893 if (!c) {
3894 s->warn = 1;
3895 } else {
3896 for (j = 0; j < c->nciphers; j++) {
3897 if (in_commasep_string(c->list[j]->name, str, len)) {
3898 s->cscipher_tobe = c->list[j];
3899 break;
3900 }
3901 }
3902 }
3903 if (s->cscipher_tobe) {
3904 if (s->warn)
3905 askcipher(ssh->frontend, s->cscipher_tobe->name, 1);
3906 break;
3907 }
3908 }
3909 if (!s->cscipher_tobe) {
3910 bombout((ssh,"Couldn't agree a client-to-server cipher (available: %s)",
3911 str ? str : "(null)"));
3912 crReturn(0);
3913 }
3914
3915 ssh2_pkt_getstring(ssh, &str, &len); /* server->client cipher */
3916 s->warn = 0;
3917 for (i = 0; i < s->n_preferred_ciphers; i++) {
3918 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3919 if (!c) {
3920 s->warn = 1;
3921 } else {
3922 for (j = 0; j < c->nciphers; j++) {
3923 if (in_commasep_string(c->list[j]->name, str, len)) {
3924 s->sccipher_tobe = c->list[j];
3925 break;
3926 }
3927 }
3928 }
3929 if (s->sccipher_tobe) {
3930 if (s->warn)
3931 askcipher(ssh->frontend, s->sccipher_tobe->name, 2);
3932 break;
3933 }
3934 }
3935 if (!s->sccipher_tobe) {
3936 bombout((ssh,"Couldn't agree a server-to-client cipher (available: %s)",
3937 str ? str : "(null)"));
3938 crReturn(0);
3939 }
3940
3941 ssh2_pkt_getstring(ssh, &str, &len); /* client->server mac */
3942 for (i = 0; i < s->nmacs; i++) {
3943 if (in_commasep_string(s->maclist[i]->name, str, len)) {
3944 s->csmac_tobe = s->maclist[i];
3945 break;
3946 }
3947 }
3948 ssh2_pkt_getstring(ssh, &str, &len); /* server->client mac */
3949 for (i = 0; i < s->nmacs; i++) {
3950 if (in_commasep_string(s->maclist[i]->name, str, len)) {
3951 s->scmac_tobe = s->maclist[i];
3952 break;
3953 }
3954 }
3955 ssh2_pkt_getstring(ssh, &str, &len); /* client->server compression */
3956 for (i = 0; i < lenof(compressions) + 1; i++) {
3957 const struct ssh_compress *c =
3958 i == 0 ? s->preferred_comp : compressions[i - 1];
3959 if (in_commasep_string(c->name, str, len)) {
3960 s->cscomp_tobe = c;
3961 break;
3962 }
3963 }
3964 ssh2_pkt_getstring(ssh, &str, &len); /* server->client compression */
3965 for (i = 0; i < lenof(compressions) + 1; i++) {
3966 const struct ssh_compress *c =
3967 i == 0 ? s->preferred_comp : compressions[i - 1];
3968 if (in_commasep_string(c->name, str, len)) {
3969 s->sccomp_tobe = c;
3970 break;
3971 }
3972 }
3973 }
3974
3975 /*
3976 * Work out the number of bits of key we will need from the key
3977 * exchange. We start with the maximum key length of either
3978 * cipher...
3979 */
3980 {
3981 int csbits, scbits;
3982
3983 csbits = s->cscipher_tobe->keylen;
3984 scbits = s->sccipher_tobe->keylen;
3985 s->nbits = (csbits > scbits ? csbits : scbits);
3986 }
3987 /* The keys only have 160-bit entropy, since they're based on
3988 * a SHA-1 hash. So cap the key size at 160 bits. */
3989 if (s->nbits > 160)
3990 s->nbits = 160;
3991
3992 /*
3993 * If we're doing Diffie-Hellman group exchange, start by
3994 * requesting a group.
3995 */
3996 if (ssh->kex == &ssh_diffiehellman_gex) {
3997 logevent("Doing Diffie-Hellman group exchange");
3998 ssh->pkt_ctx |= SSH2_PKTCTX_DHGEX;
3999 /*
4000 * Work out how big a DH group we will need to allow that
4001 * much data.
4002 */
4003 s->pbits = 512 << ((s->nbits - 1) / 64);
4004 ssh2_pkt_init(ssh, SSH2_MSG_KEX_DH_GEX_REQUEST);
4005 ssh2_pkt_adduint32(ssh, s->pbits);
4006 ssh2_pkt_send(ssh);
4007
4008 crWaitUntil(ispkt);
4009 if (ssh->pktin.type != SSH2_MSG_KEX_DH_GEX_GROUP) {
4010 bombout((ssh,"expected key exchange group packet from server"));
4011 crReturn(0);
4012 }
4013 s->p = ssh2_pkt_getmp(ssh);
4014 s->g = ssh2_pkt_getmp(ssh);
4015 ssh->kex_ctx = dh_setup_group(s->p, s->g);
4016 s->kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT;
4017 s->kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY;
4018 } else {
4019 ssh->pkt_ctx |= SSH2_PKTCTX_DHGROUP1;
4020 ssh->kex_ctx = dh_setup_group1();
4021 s->kex_init_value = SSH2_MSG_KEXDH_INIT;
4022 s->kex_reply_value = SSH2_MSG_KEXDH_REPLY;
4023 }
4024
4025 logevent("Doing Diffie-Hellman key exchange");
4026 /*
4027 * Now generate and send e for Diffie-Hellman.
4028 */
4029 s->e = dh_create_e(ssh->kex_ctx, s->nbits * 2);
4030 ssh2_pkt_init(ssh, s->kex_init_value);
4031 ssh2_pkt_addmp(ssh, s->e);
4032 ssh2_pkt_send(ssh);
4033
4034 crWaitUntil(ispkt);
4035 if (ssh->pktin.type != s->kex_reply_value) {
4036 bombout((ssh,"expected key exchange reply packet from server"));
4037 crReturn(0);
4038 }
4039 ssh2_pkt_getstring(ssh, &s->hostkeydata, &s->hostkeylen);
4040 s->f = ssh2_pkt_getmp(ssh);
4041 ssh2_pkt_getstring(ssh, &s->sigdata, &s->siglen);
4042
4043 s->K = dh_find_K(ssh->kex_ctx, s->f);
4044
4045 sha_string(&ssh->exhash, s->hostkeydata, s->hostkeylen);
4046 if (ssh->kex == &ssh_diffiehellman_gex) {
4047 sha_uint32(&ssh->exhash, s->pbits);
4048 sha_mpint(&ssh->exhash, s->p);
4049 sha_mpint(&ssh->exhash, s->g);
4050 }
4051 sha_mpint(&ssh->exhash, s->e);
4052 sha_mpint(&ssh->exhash, s->f);
4053 sha_mpint(&ssh->exhash, s->K);
4054 SHA_Final(&ssh->exhash, s->exchange_hash);
4055
4056 dh_cleanup(ssh->kex_ctx);
4057 ssh->kex_ctx = NULL;
4058
4059 #if 0
4060 debug(("Exchange hash is:\n"));
4061 dmemdump(s->exchange_hash, 20);
4062 #endif
4063
4064 s->hkey = ssh->hostkey->newkey(s->hostkeydata, s->hostkeylen);
4065 if (!s->hkey ||
4066 !ssh->hostkey->verifysig(s->hkey, s->sigdata, s->siglen,
4067 (char *)s->exchange_hash, 20)) {
4068 bombout((ssh,"Server's host key did not match the signature supplied"));
4069 crReturn(0);
4070 }
4071
4072 /*
4073 * Authenticate remote host: verify host key. (We've already
4074 * checked the signature of the exchange hash.)
4075 */
4076 s->keystr = ssh->hostkey->fmtkey(s->hkey);
4077 s->fingerprint = ssh->hostkey->fingerprint(s->hkey);
4078 verify_ssh_host_key(ssh->frontend,
4079 ssh->savedhost, ssh->savedport, ssh->hostkey->keytype,
4080 s->keystr, s->fingerprint);
4081 if (s->first_kex) { /* don't bother logging this in rekeys */
4082 logevent("Host key fingerprint is:");
4083 logevent(s->fingerprint);
4084 }
4085 sfree(s->fingerprint);
4086 sfree(s->keystr);
4087 ssh->hostkey->freekey(s->hkey);
4088
4089 /*
4090 * Send SSH2_MSG_NEWKEYS.
4091 */
4092 ssh2_pkt_init(ssh, SSH2_MSG_NEWKEYS);
4093 ssh2_pkt_send(ssh);
4094
4095 /*
4096 * Expect SSH2_MSG_NEWKEYS from server.
4097 */
4098 crWaitUntil(ispkt);
4099 if (ssh->pktin.type != SSH2_MSG_NEWKEYS) {
4100 bombout((ssh,"expected new-keys packet from server"));
4101 crReturn(0);
4102 }
4103
4104 /*
4105 * Create and initialise session keys.
4106 */
4107 if (ssh->cs_cipher_ctx)
4108 ssh->cscipher->free_context(ssh->cs_cipher_ctx);
4109 ssh->cscipher = s->cscipher_tobe;
4110 ssh->cs_cipher_ctx = ssh->cscipher->make_context();
4111
4112 if (ssh->sc_cipher_ctx)
4113 ssh->sccipher->free_context(ssh->sc_cipher_ctx);
4114 ssh->sccipher = s->sccipher_tobe;
4115 ssh->sc_cipher_ctx = ssh->sccipher->make_context();
4116
4117 if (ssh->cs_mac_ctx)
4118 ssh->csmac->free_context(ssh->cs_mac_ctx);
4119 ssh->csmac = s->csmac_tobe;
4120 ssh->cs_mac_ctx = ssh->csmac->make_context();
4121
4122 if (ssh->sc_mac_ctx)
4123 ssh->scmac->free_context(ssh->sc_mac_ctx);
4124 ssh->scmac = s->scmac_tobe;
4125 ssh->sc_mac_ctx = ssh->scmac->make_context();
4126
4127 if (ssh->cs_comp_ctx)
4128 ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
4129 ssh->cscomp = s->cscomp_tobe;
4130 ssh->cs_comp_ctx = ssh->cscomp->compress_init();
4131
4132 if (ssh->sc_comp_ctx)
4133 ssh->sccomp->decompress_cleanup(ssh->sc_comp_ctx);
4134 ssh->sccomp = s->sccomp_tobe;
4135 ssh->sc_comp_ctx = ssh->sccomp->decompress_init();
4136
4137 /*
4138 * Set IVs after keys. Here we use the exchange hash from the
4139 * _first_ key exchange.
4140 */
4141 {
4142 unsigned char keyspace[40];
4143 if (s->first_kex)
4144 memcpy(ssh->v2_session_id, s->exchange_hash,
4145 sizeof(s->exchange_hash));
4146 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'C',keyspace);
4147 ssh->cscipher->setkey(ssh->cs_cipher_ctx, keyspace);
4148 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'D',keyspace);
4149 ssh->sccipher->setkey(ssh->sc_cipher_ctx, keyspace);
4150 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'A',keyspace);
4151 ssh->cscipher->setiv(ssh->cs_cipher_ctx, keyspace);
4152 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'B',keyspace);
4153 ssh->sccipher->setiv(ssh->sc_cipher_ctx, keyspace);
4154 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'E',keyspace);
4155 ssh->csmac->setkey(ssh->cs_mac_ctx, keyspace);
4156 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'F',keyspace);
4157 ssh->scmac->setkey(ssh->sc_mac_ctx, keyspace);
4158 }
4159 logeventf(ssh, "Initialised %.200s client->server encryption",
4160 ssh->cscipher->text_name);
4161 logeventf(ssh, "Initialised %.200s server->client encryption",
4162 ssh->sccipher->text_name);
4163 if (ssh->cscomp->text_name)
4164 logeventf(ssh, "Initialised %s compression",
4165 ssh->cscomp->text_name);
4166 if (ssh->sccomp->text_name)
4167 logeventf(ssh, "Initialised %s decompression",
4168 ssh->sccomp->text_name);
4169
4170 /*
4171 * If this is the first key exchange phase, we must pass the
4172 * SSH2_MSG_NEWKEYS packet to the next layer, not because it
4173 * wants to see it but because it will need time to initialise
4174 * itself before it sees an actual packet. In subsequent key
4175 * exchange phases, we don't pass SSH2_MSG_NEWKEYS on, because
4176 * it would only confuse the layer above.
4177 */
4178 if (!s->first_kex) {
4179 crReturn(0);
4180 }
4181 s->first_kex = 0;
4182
4183 /*
4184 * Now we're encrypting. Begin returning 1 to the protocol main
4185 * function so that other things can run on top of the
4186 * transport. If we ever see a KEXINIT, we must go back to the
4187 * start.
4188 */
4189 while (!(ispkt && ssh->pktin.type == SSH2_MSG_KEXINIT)) {
4190 crReturn(1);
4191 }
4192 logevent("Server initiated key re-exchange");
4193 goto begin_key_exchange;
4194
4195 crFinish(1);
4196 }
4197
4198 /*
4199 * Add data to an SSH2 channel output buffer.
4200 */
4201 static void ssh2_add_channel_data(struct ssh_channel *c, char *buf,
4202 int len)
4203 {
4204 bufchain_add(&c->v.v2.outbuffer, buf, len);
4205 }
4206
4207 /*
4208 * Attempt to send data on an SSH2 channel.
4209 */
4210 static int ssh2_try_send(struct ssh_channel *c)
4211 {
4212 Ssh ssh = c->ssh;
4213
4214 while (c->v.v2.remwindow > 0 && bufchain_size(&c->v.v2.outbuffer) > 0) {
4215 int len;
4216 void *data;
4217 bufchain_prefix(&c->v.v2.outbuffer, &data, &len);
4218 if ((unsigned)len > c->v.v2.remwindow)
4219 len = c->v.v2.remwindow;
4220 if ((unsigned)len > c->v.v2.remmaxpkt)
4221 len = c->v.v2.remmaxpkt;
4222 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_DATA);
4223 ssh2_pkt_adduint32(ssh, c->remoteid);
4224 ssh2_pkt_addstring_start(ssh);
4225 ssh2_pkt_addstring_data(ssh, data, len);
4226 ssh2_pkt_send(ssh);
4227 bufchain_consume(&c->v.v2.outbuffer, len);
4228 c->v.v2.remwindow -= len;
4229 }
4230
4231 /*
4232 * After having sent as much data as we can, return the amount
4233 * still buffered.
4234 */
4235 return bufchain_size(&c->v.v2.outbuffer);
4236 }
4237
4238 /*
4239 * Potentially enlarge the window on an SSH2 channel.
4240 */
4241 static void ssh2_set_window(struct ssh_channel *c, unsigned newwin)
4242 {
4243 Ssh ssh = c->ssh;
4244
4245 /*
4246 * Never send WINDOW_ADJUST for a channel that the remote side
4247 * already thinks it's closed; there's no point, since it won't
4248 * be sending any more data anyway.
4249 */
4250 if (c->closes != 0)
4251 return;
4252
4253 if (newwin > c->v.v2.locwindow) {
4254 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST);
4255 ssh2_pkt_adduint32(ssh, c->remoteid);
4256 ssh2_pkt_adduint32(ssh, newwin - c->v.v2.locwindow);
4257 ssh2_pkt_send(ssh);
4258 c->v.v2.locwindow = newwin;
4259 }
4260 }
4261
4262 /*
4263 * Handle the SSH2 userauth and connection layers.
4264 */
4265 static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
4266 {
4267 struct do_ssh2_authconn_state {
4268 enum {
4269 AUTH_INVALID, AUTH_PUBLICKEY_AGENT, AUTH_PUBLICKEY_FILE,
4270 AUTH_PASSWORD,
4271 AUTH_KEYBOARD_INTERACTIVE
4272 } method;
4273 enum {
4274 AUTH_TYPE_NONE,
4275 AUTH_TYPE_PUBLICKEY,
4276 AUTH_TYPE_PUBLICKEY_OFFER_LOUD,
4277 AUTH_TYPE_PUBLICKEY_OFFER_QUIET,
4278 AUTH_TYPE_PASSWORD,
4279 AUTH_TYPE_KEYBOARD_INTERACTIVE,
4280 AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET
4281 } type;
4282 int gotit, need_pw, can_pubkey, can_passwd, can_keyb_inter;
4283 int tried_pubkey_config, tried_agent, tried_keyb_inter;
4284 int kbd_inter_running;
4285 int we_are_in;
4286 int num_prompts, curr_prompt, echo;
4287 char username[100];
4288 int got_username;
4289 char pwprompt[200];
4290 char password[100];
4291 void *publickey_blob;
4292 int publickey_bloblen;
4293 unsigned char request[5], *response, *p;
4294 int responselen;
4295 int keyi, nkeys;
4296 int authed;
4297 char *pkblob, *alg, *commentp;
4298 int pklen, alglen, commentlen;
4299 int siglen, retlen, len;
4300 char *q, *agentreq, *ret;
4301 int try_send;
4302 };
4303 crState(do_ssh2_authconn_state);
4304
4305 crBegin(ssh->do_ssh2_authconn_crstate);
4306
4307 /*
4308 * Request userauth protocol, and await a response to it.
4309 */
4310 ssh2_pkt_init(ssh, SSH2_MSG_SERVICE_REQUEST);
4311 ssh2_pkt_addstring(ssh, "ssh-userauth");
4312 ssh2_pkt_send(ssh);
4313 crWaitUntilV(ispkt);
4314 if (ssh->pktin.type != SSH2_MSG_SERVICE_ACCEPT) {
4315 bombout((ssh,"Server refused user authentication protocol"));
4316 crReturnV;
4317 }
4318
4319 /*
4320 * We repeat this whole loop, including the username prompt,
4321 * until we manage a successful authentication. If the user
4322 * types the wrong _password_, they can be sent back to the
4323 * beginning to try another username, if this is configured on.
4324 * (If they specify a username in the config, they are never
4325 * asked, even if they do give a wrong password.)
4326 *
4327 * I think this best serves the needs of
4328 *
4329 * - the people who have no configuration, no keys, and just
4330 * want to try repeated (username,password) pairs until they
4331 * type both correctly
4332 *
4333 * - people who have keys and configuration but occasionally
4334 * need to fall back to passwords
4335 *
4336 * - people with a key held in Pageant, who might not have
4337 * logged in to a particular machine before; so they want to
4338 * type a username, and then _either_ their key will be
4339 * accepted, _or_ they will type a password. If they mistype
4340 * the username they will want to be able to get back and
4341 * retype it!
4342 */
4343 s->username[0] = '\0';
4344 s->got_username = FALSE;
4345 do {
4346 /*
4347 * Get a username.
4348 */
4349 if (s->got_username && !ssh->cfg.change_username) {
4350 /*
4351 * We got a username last time round this loop, and
4352 * with change_username turned off we don't try to get
4353 * it again.
4354 */
4355 } else if ((flags & FLAG_INTERACTIVE) && !*ssh->cfg.username) {
4356 if (ssh_get_line && !ssh_getline_pw_only) {
4357 if (!ssh_get_line("login as: ",
4358 s->username, sizeof(s->username), FALSE)) {
4359 /*
4360 * get_line failed to get a username.
4361 * Terminate.
4362 */
4363 logevent("No username provided. Abandoning session.");
4364 ssh->state = SSH_STATE_CLOSED;
4365 crReturnV;
4366 }
4367 } else {
4368 int ret; /* need not be saved across crReturn */
4369 c_write_str(ssh, "login as: ");
4370 ssh->send_ok = 1;
4371 setup_userpass_input(ssh, s->username, sizeof(s->username), 1);
4372 do {
4373 crWaitUntilV(!ispkt);
4374 ret = process_userpass_input(ssh, in, inlen);
4375 } while (ret == 0);
4376 if (ret < 0)
4377 cleanup_exit(0);
4378 c_write_str(ssh, "\r\n");
4379 }
4380 s->username[strcspn(s->username, "\n\r")] = '\0';
4381 } else {
4382 char *stuff;
4383 strncpy(s->username, ssh->cfg.username, sizeof(s->username));
4384 s->username[sizeof(s->username)-1] = '\0';
4385 if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
4386 stuff = dupprintf("Using username \"%s\".\r\n", s->username);
4387 c_write_str(ssh, stuff);
4388 sfree(stuff);
4389 }
4390 }
4391 s->got_username = TRUE;
4392
4393 /*
4394 * Send an authentication request using method "none": (a)
4395 * just in case it succeeds, and (b) so that we know what
4396 * authentication methods we can usefully try next.
4397 */
4398 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4399
4400 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4401 ssh2_pkt_addstring(ssh, s->username);
4402 ssh2_pkt_addstring(ssh, "ssh-connection");/* service requested */
4403 ssh2_pkt_addstring(ssh, "none"); /* method */
4404 ssh2_pkt_send(ssh);
4405 s->type = AUTH_TYPE_NONE;
4406 s->gotit = FALSE;
4407 s->we_are_in = FALSE;
4408
4409 s->tried_pubkey_config = FALSE;
4410 s->tried_agent = FALSE;
4411 s->tried_keyb_inter = FALSE;
4412 s->kbd_inter_running = FALSE;
4413 /* Load the pub half of ssh->cfg.keyfile so we notice if it's in Pageant */
4414 if (!filename_is_null(ssh->cfg.keyfile)) {
4415 int keytype;
4416 logeventf(ssh, "Reading private key file \"%.150s\"",
4417 filename_to_str(&ssh->cfg.keyfile));
4418 keytype = key_type(&ssh->cfg.keyfile);
4419 if (keytype == SSH_KEYTYPE_SSH2) {
4420 s->publickey_blob =
4421 ssh2_userkey_loadpub(&ssh->cfg.keyfile, NULL,
4422 &s->publickey_bloblen);
4423 } else {
4424 char *msgbuf;
4425 logeventf(ssh, "Unable to use this key file (%s)",
4426 key_type_to_str(keytype));
4427 msgbuf = dupprintf("Unable to use key file \"%.150s\""
4428 " (%s)\r\n",
4429 filename_to_str(&ssh->cfg.keyfile),
4430 key_type_to_str(keytype));
4431 c_write_str(ssh, msgbuf);
4432 sfree(msgbuf);
4433 s->publickey_blob = NULL;
4434 }
4435 } else
4436 s->publickey_blob = NULL;
4437
4438 while (1) {
4439 /*
4440 * Wait for the result of the last authentication request.
4441 */
4442 if (!s->gotit)
4443 crWaitUntilV(ispkt);
4444 while (ssh->pktin.type == SSH2_MSG_USERAUTH_BANNER) {
4445 char *banner;
4446 int size;
4447 /*
4448 * Don't show the banner if we're operating in
4449 * non-verbose non-interactive mode. (It's probably
4450 * a script, which means nobody will read the
4451 * banner _anyway_, and moreover the printing of
4452 * the banner will screw up processing on the
4453 * output of (say) plink.)
4454 */
4455 if (flags & (FLAG_VERBOSE | FLAG_INTERACTIVE)) {
4456 ssh2_pkt_getstring(ssh, &banner, &size);
4457 if (banner)
4458 c_write_untrusted(ssh, banner, size);
4459 }
4460 crWaitUntilV(ispkt);
4461 }
4462 if (ssh->pktin.type == SSH2_MSG_USERAUTH_SUCCESS) {
4463 logevent("Access granted");
4464 s->we_are_in = TRUE;
4465 break;
4466 }
4467
4468 if (s->kbd_inter_running &&
4469 ssh->pktin.type == SSH2_MSG_USERAUTH_INFO_REQUEST) {
4470 /*
4471 * This is either a further set-of-prompts packet
4472 * in keyboard-interactive authentication, or it's
4473 * the same one and we came back here with `gotit'
4474 * set. In the former case, we must reset the
4475 * curr_prompt variable.
4476 */
4477 if (!s->gotit)
4478 s->curr_prompt = 0;
4479 } else if (ssh->pktin.type != SSH2_MSG_USERAUTH_FAILURE) {
4480 bombout((ssh,"Strange packet received during authentication: type %d",
4481 ssh->pktin.type));
4482 crReturnV;
4483 }
4484
4485 s->gotit = FALSE;
4486
4487 /*
4488 * OK, we're now sitting on a USERAUTH_FAILURE message, so
4489 * we can look at the string in it and know what we can
4490 * helpfully try next.
4491 */
4492 if (ssh->pktin.type == SSH2_MSG_USERAUTH_FAILURE) {
4493 char *methods;
4494 int methlen;
4495 ssh2_pkt_getstring(ssh, &methods, &methlen);
4496 s->kbd_inter_running = FALSE;
4497 if (!ssh2_pkt_getbool(ssh)) {
4498 /*
4499 * We have received an unequivocal Access
4500 * Denied. This can translate to a variety of
4501 * messages:
4502 *
4503 * - if we'd just tried "none" authentication,
4504 * it's not worth printing anything at all
4505 *
4506 * - if we'd just tried a public key _offer_,
4507 * the message should be "Server refused our
4508 * key" (or no message at all if the key
4509 * came from Pageant)
4510 *
4511 * - if we'd just tried anything else, the
4512 * message really should be "Access denied".
4513 *
4514 * Additionally, if we'd just tried password
4515 * authentication, we should break out of this
4516 * whole loop so as to go back to the username
4517 * prompt.
4518 */
4519 if (s->type == AUTH_TYPE_NONE) {
4520 /* do nothing */
4521 } else if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD ||
4522 s->type == AUTH_TYPE_PUBLICKEY_OFFER_QUIET) {
4523 if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD)
4524 c_write_str(ssh, "Server refused our key\r\n");
4525 logevent("Server refused public key");
4526 } else if (s->type==AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET) {
4527 /* server declined keyboard-interactive; ignore */
4528 } else {
4529 c_write_str(ssh, "Access denied\r\n");
4530 logevent("Access denied");
4531 if (s->type == AUTH_TYPE_PASSWORD) {
4532 s->we_are_in = FALSE;
4533 break;
4534 }
4535 }
4536 } else {
4537 c_write_str(ssh, "Further authentication required\r\n");
4538 logevent("Further authentication required");
4539 }
4540
4541 s->can_pubkey =
4542 in_commasep_string("publickey", methods, methlen);
4543 s->can_passwd =
4544 in_commasep_string("password", methods, methlen);
4545 s->can_keyb_inter = ssh->cfg.try_ki_auth &&
4546 in_commasep_string("keyboard-interactive", methods, methlen);
4547 }
4548
4549 s->method = 0;
4550 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4551
4552 /*
4553 * Most password/passphrase prompts will be
4554 * non-echoing, so we set this to 0 by default.
4555 * Exception is that some keyboard-interactive prompts
4556 * can be echoing, in which case we'll set this to 1.
4557 */
4558 s->echo = 0;
4559
4560 if (!s->method && s->can_pubkey &&
4561 agent_exists() && !s->tried_agent) {
4562 /*
4563 * Attempt public-key authentication using Pageant.
4564 */
4565 void *r;
4566 s->authed = FALSE;
4567
4568 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4569 ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
4570
4571 s->tried_agent = TRUE;
4572
4573 logevent("Pageant is running. Requesting keys.");
4574
4575 /* Request the keys held by the agent. */
4576 PUT_32BIT(s->request, 1);
4577 s->request[4] = SSH2_AGENTC_REQUEST_IDENTITIES;
4578 agent_query(s->request, 5, &r, &s->responselen);
4579 s->response = (unsigned char *) r;
4580 if (s->response && s->responselen >= 5 &&
4581 s->response[4] == SSH2_AGENT_IDENTITIES_ANSWER) {
4582 s->p = s->response + 5;
4583 s->nkeys = GET_32BIT(s->p);
4584 s->p += 4;
4585 {
4586 char buf[64];
4587 sprintf(buf, "Pageant has %d SSH2 keys", s->nkeys);
4588 logevent(buf);
4589 }
4590 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
4591 void *vret;
4592
4593 {
4594 char buf[64];
4595 sprintf(buf, "Trying Pageant key #%d", s->keyi);
4596 logevent(buf);
4597 }
4598 s->pklen = GET_32BIT(s->p);
4599 s->p += 4;
4600 if (s->publickey_blob &&
4601 s->pklen == s->publickey_bloblen &&
4602 !memcmp(s->p, s->publickey_blob,
4603 s->publickey_bloblen)) {
4604 logevent("This key matches configured key file");
4605 s->tried_pubkey_config = 1;
4606 }
4607 s->pkblob = (char *)s->p;
4608 s->p += s->pklen;
4609 s->alglen = GET_32BIT(s->pkblob);
4610 s->alg = s->pkblob + 4;
4611 s->commentlen = GET_32BIT(s->p);
4612 s->p += 4;
4613 s->commentp = (char *)s->p;
4614 s->p += s->commentlen;
4615 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4616 ssh2_pkt_addstring(ssh, s->username);
4617 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4618 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4619 ssh2_pkt_addbool(ssh, FALSE); /* no signature included */
4620 ssh2_pkt_addstring_start(ssh);
4621 ssh2_pkt_addstring_data(ssh, s->alg, s->alglen);
4622 ssh2_pkt_addstring_start(ssh);
4623 ssh2_pkt_addstring_data(ssh, s->pkblob, s->pklen);
4624 ssh2_pkt_send(ssh);
4625
4626 crWaitUntilV(ispkt);
4627 if (ssh->pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
4628 logevent("Key refused");
4629 continue;
4630 }
4631
4632 if (flags & FLAG_VERBOSE) {
4633 c_write_str(ssh, "Authenticating with "
4634 "public key \"");
4635 c_write(ssh, s->commentp, s->commentlen);
4636 c_write_str(ssh, "\" from agent\r\n");
4637 }
4638
4639 /*
4640 * Server is willing to accept the key.
4641 * Construct a SIGN_REQUEST.
4642 */
4643 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4644 ssh2_pkt_addstring(ssh, s->username);
4645 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4646 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4647 ssh2_pkt_addbool(ssh, TRUE);
4648 ssh2_pkt_addstring_start(ssh);
4649 ssh2_pkt_addstring_data(ssh, s->alg, s->alglen);
4650 ssh2_pkt_addstring_start(ssh);
4651 ssh2_pkt_addstring_data(ssh, s->pkblob, s->pklen);
4652
4653 s->siglen = ssh->pktout.length - 5 + 4 + 20;
4654 if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
4655 s->siglen -= 4;
4656 s->len = 1; /* message type */
4657 s->len += 4 + s->pklen; /* key blob */
4658 s->len += 4 + s->siglen; /* data to sign */
4659 s->len += 4; /* flags */
4660 s->agentreq = smalloc(4 + s->len);
4661 PUT_32BIT(s->agentreq, s->len);
4662 s->q = s->agentreq + 4;
4663 *s->q++ = SSH2_AGENTC_SIGN_REQUEST;
4664 PUT_32BIT(s->q, s->pklen);
4665 s->q += 4;
4666 memcpy(s->q, s->pkblob, s->pklen);
4667 s->q += s->pklen;
4668 PUT_32BIT(s->q, s->siglen);
4669 s->q += 4;
4670 /* Now the data to be signed... */
4671 if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
4672 PUT_32BIT(s->q, 20);
4673 s->q += 4;
4674 }
4675 memcpy(s->q, ssh->v2_session_id, 20);
4676 s->q += 20;
4677 memcpy(s->q, ssh->pktout.data + 5,
4678 ssh->pktout.length - 5);
4679 s->q += ssh->pktout.length - 5;
4680 /* And finally the (zero) flags word. */
4681 PUT_32BIT(s->q, 0);
4682 agent_query(s->agentreq, s->len + 4, &vret, &s->retlen);
4683 s->ret = vret;
4684 sfree(s->agentreq);
4685 if (s->ret) {
4686 if (s->ret[4] == SSH2_AGENT_SIGN_RESPONSE) {
4687 logevent("Sending Pageant's response");
4688 ssh2_add_sigblob(ssh, s->pkblob, s->pklen,
4689 s->ret + 9,
4690 GET_32BIT(s->ret + 5));
4691 ssh2_pkt_send(ssh);
4692 s->authed = TRUE;
4693 break;
4694 } else {
4695 logevent
4696 ("Pageant failed to answer challenge");
4697 sfree(s->ret);
4698 }
4699 }
4700 }
4701 if (s->authed)
4702 continue;
4703 }
4704 }
4705
4706 if (!s->method && s->can_pubkey && s->publickey_blob
4707 && !s->tried_pubkey_config) {
4708 unsigned char *pub_blob;
4709 char *algorithm, *comment;
4710 int pub_blob_len;
4711
4712 s->tried_pubkey_config = TRUE;
4713
4714 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4715 ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
4716
4717 /*
4718 * Try the public key supplied in the configuration.
4719 *
4720 * First, offer the public blob to see if the server is
4721 * willing to accept it.
4722 */
4723 pub_blob =
4724 (unsigned char *)ssh2_userkey_loadpub(&ssh->cfg.keyfile,
4725 &algorithm,
4726 &pub_blob_len);
4727 if (pub_blob) {
4728 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4729 ssh2_pkt_addstring(ssh, s->username);
4730 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4731 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4732 ssh2_pkt_addbool(ssh, FALSE); /* no signature included */
4733 ssh2_pkt_addstring(ssh, algorithm);
4734 ssh2_pkt_addstring_start(ssh);
4735 ssh2_pkt_addstring_data(ssh, (char *)pub_blob,
4736 pub_blob_len);
4737 ssh2_pkt_send(ssh);
4738 logevent("Offered public key"); /* FIXME */
4739
4740 crWaitUntilV(ispkt);
4741 if (ssh->pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
4742 s->gotit = TRUE;
4743 s->type = AUTH_TYPE_PUBLICKEY_OFFER_LOUD;
4744 continue; /* key refused; give up on it */
4745 }
4746
4747 logevent("Offer of public key accepted");
4748 /*
4749 * Actually attempt a serious authentication using
4750 * the key.
4751 */
4752 if (ssh2_userkey_encrypted(&ssh->cfg.keyfile, &comment)) {
4753 sprintf(s->pwprompt,
4754 "Passphrase for key \"%.100s\": ",
4755 comment);
4756 s->need_pw = TRUE;
4757 } else {
4758 s->need_pw = FALSE;
4759 }
4760 c_write_str(ssh, "Authenticating with public key \"");
4761 c_write_str(ssh, comment);
4762 c_write_str(ssh, "\"\r\n");
4763 s->method = AUTH_PUBLICKEY_FILE;
4764 }
4765 }
4766
4767 if (!s->method && s->can_keyb_inter && !s->tried_keyb_inter) {
4768 s->method = AUTH_KEYBOARD_INTERACTIVE;
4769 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
4770 s->tried_keyb_inter = TRUE;
4771
4772 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4773 ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;
4774
4775 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4776 ssh2_pkt_addstring(ssh, s->username);
4777 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4778 ssh2_pkt_addstring(ssh, "keyboard-interactive"); /* method */
4779 ssh2_pkt_addstring(ssh, ""); /* lang */
4780 ssh2_pkt_addstring(ssh, "");
4781 ssh2_pkt_send(ssh);
4782
4783 crWaitUntilV(ispkt);
4784 if (ssh->pktin.type != SSH2_MSG_USERAUTH_INFO_REQUEST) {
4785 if (ssh->pktin.type == SSH2_MSG_USERAUTH_FAILURE)
4786 s->gotit = TRUE;
4787 logevent("Keyboard-interactive authentication refused");
4788 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET;
4789 continue;
4790 }
4791
4792 s->kbd_inter_running = TRUE;
4793 s->curr_prompt = 0;
4794 }
4795
4796 if (s->kbd_inter_running) {
4797 s->method = AUTH_KEYBOARD_INTERACTIVE;
4798 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
4799 s->tried_keyb_inter = TRUE;
4800
4801 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4802 ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;
4803
4804 if (s->curr_prompt == 0) {
4805 /*
4806 * We've got a fresh USERAUTH_INFO_REQUEST.
4807 * Display header data, and start going through
4808 * the prompts.
4809 */
4810 char *name, *inst, *lang;
4811 int name_len, inst_len, lang_len;
4812
4813 ssh2_pkt_getstring(ssh, &name, &name_len);
4814 ssh2_pkt_getstring(ssh, &inst, &inst_len);
4815 ssh2_pkt_getstring(ssh, &lang, &lang_len);
4816 if (name_len > 0) {
4817 c_write_untrusted(ssh, name, name_len);
4818 c_write_str(ssh, "\r\n");
4819 }
4820 if (inst_len > 0) {
4821 c_write_untrusted(ssh, inst, inst_len);
4822 c_write_str(ssh, "\r\n");
4823 }
4824 s->num_prompts = ssh2_pkt_getuint32(ssh);
4825 }
4826
4827 /*
4828 * If there are prompts remaining in the packet,
4829 * display one and get a response.
4830 */
4831 if (s->curr_prompt < s->num_prompts) {
4832 char *prompt;
4833 int prompt_len;
4834
4835 ssh2_pkt_getstring(ssh, &prompt, &prompt_len);
4836 if (prompt_len > 0) {
4837 strncpy(s->pwprompt, prompt, sizeof(s->pwprompt));
4838 s->pwprompt[prompt_len < sizeof(s->pwprompt) ?
4839 prompt_len : sizeof(s->pwprompt)-1] = '\0';
4840 } else {
4841 strcpy(s->pwprompt,
4842 "<server failed to send prompt>: ");
4843 }
4844 s->echo = ssh2_pkt_getbool(ssh);
4845 s->need_pw = TRUE;
4846 } else
4847 s->need_pw = FALSE;
4848 }
4849
4850 if (!s->method && s->can_passwd) {
4851 s->method = AUTH_PASSWORD;
4852 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4853 ssh->pkt_ctx |= SSH2_PKTCTX_PASSWORD;
4854 sprintf(s->pwprompt, "%.90s@%.90s's password: ", s->username,
4855 ssh->savedhost);
4856 s->need_pw = TRUE;
4857 }
4858
4859 if (s->need_pw) {
4860 if (ssh_get_line) {
4861 if (!ssh_get_line(s->pwprompt, s->password,
4862 sizeof(s->password), TRUE)) {
4863 /*
4864 * get_line failed to get a password (for
4865 * example because one was supplied on the
4866 * command line which has already failed to
4867 * work). Terminate.
4868 */
4869 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
4870 ssh2_pkt_adduint32(ssh,SSH2_DISCONNECT_BY_APPLICATION);
4871 ssh2_pkt_addstring(ssh, "No more passwords available"
4872 " to try");
4873 ssh2_pkt_addstring(ssh, "en"); /* language tag */
4874 ssh2_pkt_send(ssh);
4875 logevent("Unable to authenticate");
4876 connection_fatal(ssh->frontend,
4877 "Unable to authenticate");
4878 ssh->state = SSH_STATE_CLOSED;
4879 crReturnV;
4880 }
4881 } else {
4882 int ret; /* need not be saved across crReturn */
4883 c_write_untrusted(ssh, s->pwprompt, strlen(s->pwprompt));
4884 ssh->send_ok = 1;
4885
4886 setup_userpass_input(ssh, s->password,
4887 sizeof(s->password), s->echo);
4888 do {
4889 crWaitUntilV(!ispkt);
4890 ret = process_userpass_input(ssh, in, inlen);
4891 } while (ret == 0);
4892 if (ret < 0)
4893 cleanup_exit(0);
4894 c_write_str(ssh, "\r\n");
4895 }
4896 }
4897
4898 if (s->method == AUTH_PUBLICKEY_FILE) {
4899 /*
4900 * We have our passphrase. Now try the actual authentication.
4901 */
4902 struct ssh2_userkey *key;
4903
4904 key = ssh2_load_userkey(&ssh->cfg.keyfile, s->password);
4905 if (key == SSH2_WRONG_PASSPHRASE || key == NULL) {
4906 if (key == SSH2_WRONG_PASSPHRASE) {
4907 c_write_str(ssh, "Wrong passphrase\r\n");
4908 s->tried_pubkey_config = FALSE;
4909 } else {
4910 c_write_str(ssh, "Unable to load private key\r\n");
4911 s->tried_pubkey_config = TRUE;
4912 }
4913 /* Send a spurious AUTH_NONE to return to the top. */
4914 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4915 ssh2_pkt_addstring(ssh, s->username);
4916 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4917 ssh2_pkt_addstring(ssh, "none"); /* method */
4918 ssh2_pkt_send(ssh);
4919 s->type = AUTH_TYPE_NONE;
4920 } else {
4921 unsigned char *pkblob, *sigblob, *sigdata;
4922 int pkblob_len, sigblob_len, sigdata_len;
4923 int p;
4924
4925 /*
4926 * We have loaded the private key and the server
4927 * has announced that it's willing to accept it.
4928 * Hallelujah. Generate a signature and send it.
4929 */
4930 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4931 ssh2_pkt_addstring(ssh, s->username);
4932 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4933 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4934 ssh2_pkt_addbool(ssh, TRUE);
4935 ssh2_pkt_addstring(ssh, key->alg->name);
4936 pkblob = key->alg->public_blob(key->data, &pkblob_len);
4937 ssh2_pkt_addstring_start(ssh);
4938 ssh2_pkt_addstring_data(ssh, (char *)pkblob, pkblob_len);
4939
4940 /*
4941 * The data to be signed is:
4942 *
4943 * string session-id
4944 *
4945 * followed by everything so far placed in the
4946 * outgoing packet.
4947 */
4948 sigdata_len = ssh->pktout.length - 5 + 4 + 20;
4949 if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
4950 sigdata_len -= 4;
4951 sigdata = smalloc(sigdata_len);
4952 p = 0;
4953 if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
4954 PUT_32BIT(sigdata+p, 20);
4955 p += 4;
4956 }
4957 memcpy(sigdata+p, ssh->v2_session_id, 20); p += 20;
4958 memcpy(sigdata+p, ssh->pktout.data + 5,
4959 ssh->pktout.length - 5);
4960 p += ssh->pktout.length - 5;
4961 assert(p == sigdata_len);
4962 sigblob = key->alg->sign(key->data, (char *)sigdata,
4963 sigdata_len, &sigblob_len);
4964 ssh2_add_sigblob(ssh, pkblob, pkblob_len,
4965 sigblob, sigblob_len);
4966 sfree(pkblob);
4967 sfree(sigblob);
4968 sfree(sigdata);
4969
4970 ssh2_pkt_send(ssh);
4971 s->type = AUTH_TYPE_PUBLICKEY;
4972 }
4973 } else if (s->method == AUTH_PASSWORD) {
4974 /*
4975 * We send the password packet lumped tightly together with
4976 * an SSH_MSG_IGNORE packet. The IGNORE packet contains a
4977 * string long enough to make the total length of the two
4978 * packets constant. This should ensure that a passive
4979 * listener doing traffic analyis can't work out the length
4980 * of the password.
4981 *
4982 * For this to work, we need an assumption about the
4983 * maximum length of the password packet. I think 256 is
4984 * pretty conservative. Anyone using a password longer than
4985 * that probably doesn't have much to worry about from
4986 * people who find out how long their password is!
4987 */
4988 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4989 ssh2_pkt_addstring(ssh, s->username);
4990 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4991 ssh2_pkt_addstring(ssh, "password");
4992 ssh2_pkt_addbool(ssh, FALSE);
4993 ssh2_pkt_addstring(ssh, s->password);
4994 memset(s->password, 0, sizeof(s->password));
4995 ssh2_pkt_defer(ssh);
4996 /*
4997 * We'll include a string that's an exact multiple of the
4998 * cipher block size. If the cipher is NULL for some
4999 * reason, we don't do this trick at all because we gain
5000 * nothing by it.
5001 */
5002 if (ssh->cscipher) {
5003 int stringlen, i;
5004
5005 stringlen = (256 - ssh->deferred_len);
5006 stringlen += ssh->cscipher->blksize - 1;
5007 stringlen -= (stringlen % ssh->cscipher->blksize);
5008 if (ssh->cscomp) {
5009 /*
5010 * Temporarily disable actual compression,
5011 * so we can guarantee to get this string
5012 * exactly the length we want it. The
5013 * compression-disabling routine should
5014 * return an integer indicating how many
5015 * bytes we should adjust our string length
5016 * by.
5017 */
5018 stringlen -=
5019 ssh->cscomp->disable_compression(ssh->cs_comp_ctx);
5020 }
5021 ssh2_pkt_init(ssh, SSH2_MSG_IGNORE);
5022 ssh2_pkt_addstring_start(ssh);
5023 for (i = 0; i < stringlen; i++) {
5024 char c = (char) random_byte();
5025 ssh2_pkt_addstring_data(ssh, &c, 1);
5026 }
5027 ssh2_pkt_defer(ssh);
5028 }
5029 ssh_pkt_defersend(ssh);
5030 logevent("Sent password");
5031 s->type = AUTH_TYPE_PASSWORD;
5032 } else if (s->method == AUTH_KEYBOARD_INTERACTIVE) {
5033 if (s->curr_prompt == 0) {
5034 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_INFO_RESPONSE);
5035 ssh2_pkt_adduint32(ssh, s->num_prompts);
5036 }
5037 if (s->need_pw) { /* only add pw if we just got one! */
5038 ssh2_pkt_addstring(ssh, s->password);
5039 memset(s->password, 0, sizeof(s->password));
5040 s->curr_prompt++;
5041 }
5042 if (s->curr_prompt >= s->num_prompts) {
5043 ssh2_pkt_send(ssh);
5044 } else {
5045 /*
5046 * If there are prompts remaining, we set
5047 * `gotit' so that we won't attempt to get
5048 * another packet. Then we go back round the
5049 * loop and will end up retrieving another
5050 * prompt out of the existing packet. Funky or
5051 * what?
5052 */
5053 s->gotit = TRUE;
5054 }
5055 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
5056 } else {
5057 c_write_str(ssh, "No supported authentication methods"
5058 " left to try!\r\n");
5059 logevent("No supported authentications offered."
5060 " Disconnecting");
5061 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5062 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5063 ssh2_pkt_addstring(ssh, "No supported authentication"
5064 " methods available");
5065 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5066 ssh2_pkt_send(ssh);
5067 ssh->state = SSH_STATE_CLOSED;
5068 crReturnV;
5069 }
5070 }
5071 } while (!s->we_are_in);
5072
5073 /*
5074 * Now we're authenticated for the connection protocol. The
5075 * connection protocol will automatically have started at this
5076 * point; there's no need to send SERVICE_REQUEST.
5077 */
5078
5079 /*
5080 * So now create a channel with a session in it.
5081 */
5082 ssh->channels = newtree234(ssh_channelcmp);
5083 ssh->mainchan = smalloc(sizeof(struct ssh_channel));
5084 ssh->mainchan->ssh = ssh;
5085 ssh->mainchan->localid = alloc_channel_id(ssh);
5086 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN);
5087 ssh2_pkt_addstring(ssh, "session");
5088 ssh2_pkt_adduint32(ssh, ssh->mainchan->localid);
5089 ssh->mainchan->v.v2.locwindow = OUR_V2_WINSIZE;
5090 ssh2_pkt_adduint32(ssh, ssh->mainchan->v.v2.locwindow);/* our window size */
5091 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
5092 ssh2_pkt_send(ssh);
5093 crWaitUntilV(ispkt);
5094 if (ssh->pktin.type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
5095 bombout((ssh,"Server refused to open a session"));
5096 crReturnV;
5097 /* FIXME: error data comes back in FAILURE packet */
5098 }
5099 if (ssh2_pkt_getuint32(ssh) != ssh->mainchan->localid) {
5100 bombout((ssh,"Server's channel confirmation cited wrong channel"));
5101 crReturnV;
5102 }
5103 ssh->mainchan->remoteid = ssh2_pkt_getuint32(ssh);
5104 ssh->mainchan->type = CHAN_MAINSESSION;
5105 ssh->mainchan->closes = 0;
5106 ssh->mainchan->v.v2.remwindow = ssh2_pkt_getuint32(ssh);
5107 ssh->mainchan->v.v2.remmaxpkt = ssh2_pkt_getuint32(ssh);
5108 bufchain_init(&ssh->mainchan->v.v2.outbuffer);
5109 add234(ssh->channels, ssh->mainchan);
5110 logevent("Opened channel for session");
5111
5112 /*
5113 * Potentially enable X11 forwarding.
5114 */
5115 if (ssh->cfg.x11_forward) {
5116 char proto[20], data[64];
5117 logevent("Requesting X11 forwarding");
5118 ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
5119 data, sizeof(data), ssh->cfg.x11_auth);
5120 x11_get_real_auth(ssh->x11auth, ssh->cfg.x11_display);
5121 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5122 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
5123 ssh2_pkt_addstring(ssh, "x11-req");
5124 ssh2_pkt_addbool(ssh, 1); /* want reply */
5125 ssh2_pkt_addbool(ssh, 0); /* many connections */
5126 ssh2_pkt_addstring(ssh, proto);
5127 ssh2_pkt_addstring(ssh, data);
5128 ssh2_pkt_adduint32(ssh, x11_get_screen_number(ssh->cfg.x11_display));
5129 ssh2_pkt_send(ssh);
5130
5131 do {
5132 crWaitUntilV(ispkt);
5133 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5134 unsigned i = ssh2_pkt_getuint32(ssh);
5135 struct ssh_channel *c;
5136 c = find234(ssh->channels, &i, ssh_channelfind);
5137 if (!c)
5138 continue; /* nonexistent channel */
5139 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5140 }
5141 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5142
5143 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5144 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5145 bombout((ssh,"Unexpected response to X11 forwarding request:"
5146 " packet type %d", ssh->pktin.type));
5147 crReturnV;
5148 }
5149 logevent("X11 forwarding refused");
5150 } else {
5151 logevent("X11 forwarding enabled");
5152 ssh->X11_fwd_enabled = TRUE;
5153 }
5154 }
5155
5156 /*
5157 * Enable port forwardings.
5158 */
5159 {
5160 char type;
5161 int n;
5162 int sport,dport,sserv,dserv;
5163 char sports[256], dports[256], saddr[256], host[256];
5164
5165 ssh->rportfwds = newtree234(ssh_rportcmp_ssh2);
5166 /* Add port forwardings. */
5167 ssh->portfwd_strptr = ssh->cfg.portfwd;
5168 while (*ssh->portfwd_strptr) {
5169 type = *ssh->portfwd_strptr++;
5170 saddr[0] = '\0';
5171 n = 0;
5172 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != '\t') {
5173 if (*ssh->portfwd_strptr == ':') {
5174 /*
5175 * We've seen a colon in the middle of the
5176 * source port number. This means that
5177 * everything we've seen until now is the
5178 * source _address_, so we'll move it into
5179 * saddr and start sports from the beginning
5180 * again.
5181 */
5182 ssh->portfwd_strptr++;
5183 sports[n] = '\0';
5184 strcpy(saddr, sports);
5185 n = 0;
5186 }
5187 if (n < 255) sports[n++] = *ssh->portfwd_strptr++;
5188 }
5189 sports[n] = 0;
5190 if (*ssh->portfwd_strptr == '\t')
5191 ssh->portfwd_strptr++;
5192 n = 0;
5193 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':') {
5194 if (n < 255) host[n++] = *ssh->portfwd_strptr++;
5195 }
5196 host[n] = 0;
5197 if (*ssh->portfwd_strptr == ':')
5198 ssh->portfwd_strptr++;
5199 n = 0;
5200 while (*ssh->portfwd_strptr) {
5201 if (n < 255) dports[n++] = *ssh->portfwd_strptr++;
5202 }
5203 dports[n] = 0;
5204 ssh->portfwd_strptr++;
5205 dport = atoi(dports);
5206 dserv = 0;
5207 if (dport == 0) {
5208 dserv = 1;
5209 dport = net_service_lookup(dports);
5210 if (!dport) {
5211 logeventf(ssh, "Service lookup failed for destination"
5212 " port \"%s\"", dports);
5213 }
5214 }
5215 sport = atoi(sports);
5216 sserv = 0;
5217 if (sport == 0) {
5218 sserv = 1;
5219 sport = net_service_lookup(sports);
5220 if (!sport) {
5221 logeventf(ssh, "Service lookup failed for source"
5222 " port \"%s\"", sports);
5223 }
5224 }
5225 if (sport && dport) {
5226 if (type == 'L') {
5227 pfd_addforward(host, dport, *saddr ? saddr : NULL,
5228 sport, ssh, &ssh->cfg);
5229 logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
5230 " forwarding to %s:%.*s%.*s%d%.*s",
5231 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
5232 (int)(*saddr?1:0), ":",
5233 (int)(sserv ? strlen(sports) : 0), sports,
5234 sserv, "(", sport, sserv, ")",
5235 host,
5236 (int)(dserv ? strlen(dports) : 0), dports,
5237 dserv, "(", dport, dserv, ")");
5238 } else {
5239 struct ssh_rportfwd *pf;
5240 pf = smalloc(sizeof(*pf));
5241 strcpy(pf->dhost, host);
5242 pf->dport = dport;
5243 pf->sport = sport;
5244 if (add234(ssh->rportfwds, pf) != pf) {
5245 logeventf(ssh, "Duplicate remote port forwarding"
5246 " to %s:%d", host, dport);
5247 sfree(pf);
5248 } else {
5249 logeventf(ssh, "Requesting remote port "
5250 "%.*s%.*s%.*s%.*s%d%.*s"
5251 " forward to %s:%.*s%.*s%d%.*s",
5252 (int)(*saddr?strlen(saddr):0),
5253 *saddr?saddr:NULL,
5254 (int)(*saddr?1:0), ":",
5255 (int)(sserv ? strlen(sports) : 0), sports,
5256 sserv, "(", sport, sserv, ")",
5257 host,
5258 (int)(dserv ? strlen(dports) : 0), dports,
5259 dserv, "(", dport, dserv, ")");
5260 ssh2_pkt_init(ssh, SSH2_MSG_GLOBAL_REQUEST);
5261 ssh2_pkt_addstring(ssh, "tcpip-forward");
5262 ssh2_pkt_addbool(ssh, 1);/* want reply */
5263 if (*saddr)
5264 ssh2_pkt_addstring(ssh, saddr);
5265 if (ssh->cfg.rport_acceptall)
5266 ssh2_pkt_addstring(ssh, "0.0.0.0");
5267 else
5268 ssh2_pkt_addstring(ssh, "127.0.0.1");
5269 ssh2_pkt_adduint32(ssh, sport);
5270 ssh2_pkt_send(ssh);
5271
5272 do {
5273 crWaitUntilV(ispkt);
5274 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5275 unsigned i = ssh2_pkt_getuint32(ssh);
5276 struct ssh_channel *c;
5277 c = find234(ssh->channels, &i, ssh_channelfind);
5278 if (!c)
5279 continue;/* nonexistent channel */
5280 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5281 }
5282 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5283
5284 if (ssh->pktin.type != SSH2_MSG_REQUEST_SUCCESS) {
5285 if (ssh->pktin.type != SSH2_MSG_REQUEST_FAILURE) {
5286 bombout((ssh,"Unexpected response to port "
5287 "forwarding request: packet type %d",
5288 ssh->pktin.type));
5289 crReturnV;
5290 }
5291 logevent("Server refused this port forwarding");
5292 } else {
5293 logevent("Remote port forwarding enabled");
5294 }
5295 }
5296 }
5297 }
5298 }
5299 }
5300
5301 /*
5302 * Potentially enable agent forwarding.
5303 */
5304 if (ssh->cfg.agentfwd && agent_exists()) {
5305 logevent("Requesting OpenSSH-style agent forwarding");
5306 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5307 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
5308 ssh2_pkt_addstring(ssh, "auth-agent-req@openssh.com");
5309 ssh2_pkt_addbool(ssh, 1); /* want reply */
5310 ssh2_pkt_send(ssh);
5311
5312 do {
5313 crWaitUntilV(ispkt);
5314 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5315 unsigned i = ssh2_pkt_getuint32(ssh);
5316 struct ssh_channel *c;
5317 c = find234(ssh->channels, &i, ssh_channelfind);
5318 if (!c)
5319 continue; /* nonexistent channel */
5320 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5321 }
5322 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5323
5324 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5325 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5326 bombout((ssh,"Unexpected response to agent forwarding request:"
5327 " packet type %d", ssh->pktin.type));
5328 crReturnV;
5329 }
5330 logevent("Agent forwarding refused");
5331 } else {
5332 logevent("Agent forwarding enabled");
5333 ssh->agentfwd_enabled = TRUE;
5334 }
5335 }
5336
5337 /*
5338 * Now allocate a pty for the session.
5339 */
5340 if (!ssh->cfg.nopty) {
5341 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5342 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid); /* recipient channel */
5343 ssh2_pkt_addstring(ssh, "pty-req");
5344 ssh2_pkt_addbool(ssh, 1); /* want reply */
5345 ssh2_pkt_addstring(ssh, ssh->cfg.termtype);
5346 ssh2_pkt_adduint32(ssh, ssh->term_width);
5347 ssh2_pkt_adduint32(ssh, ssh->term_height);
5348 ssh2_pkt_adduint32(ssh, 0); /* pixel width */
5349 ssh2_pkt_adduint32(ssh, 0); /* pixel height */
5350 ssh2_pkt_addstring_start(ssh);
5351 ssh2_pkt_addstring_data(ssh, "\0", 1); /* TTY_OP_END, no special options */
5352 ssh2_pkt_send(ssh);
5353 ssh->state = SSH_STATE_INTERMED;
5354
5355 do {
5356 crWaitUntilV(ispkt);
5357 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5358 unsigned i = ssh2_pkt_getuint32(ssh);
5359 struct ssh_channel *c;
5360 c = find234(ssh->channels, &i, ssh_channelfind);
5361 if (!c)
5362 continue; /* nonexistent channel */
5363 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5364 }
5365 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5366
5367 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5368 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5369 bombout((ssh,"Unexpected response to pty request:"
5370 " packet type %d", ssh->pktin.type));
5371 crReturnV;
5372 }
5373 c_write_str(ssh, "Server refused to allocate pty\r\n");
5374 ssh->editing = ssh->echoing = 1;
5375 } else {
5376 logevent("Allocated pty");
5377 }
5378 } else {
5379 ssh->editing = ssh->echoing = 1;
5380 }
5381
5382 /*
5383 * Start a shell or a remote command. We may have to attempt
5384 * this twice if the config data has provided a second choice
5385 * of command.
5386 */
5387 while (1) {
5388 int subsys;
5389 char *cmd;
5390
5391 if (ssh->fallback_cmd) {
5392 subsys = ssh->cfg.ssh_subsys2;
5393 cmd = ssh->cfg.remote_cmd_ptr2;
5394 } else {
5395 subsys = ssh->cfg.ssh_subsys;
5396 cmd = ssh->cfg.remote_cmd_ptr;
5397 }
5398
5399 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5400 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid); /* recipient channel */
5401 if (subsys) {
5402 ssh2_pkt_addstring(ssh, "subsystem");
5403 ssh2_pkt_addbool(ssh, 1); /* want reply */
5404 ssh2_pkt_addstring(ssh, cmd);
5405 } else if (*cmd) {
5406 ssh2_pkt_addstring(ssh, "exec");
5407 ssh2_pkt_addbool(ssh, 1); /* want reply */
5408 ssh2_pkt_addstring(ssh, cmd);
5409 } else {
5410 ssh2_pkt_addstring(ssh, "shell");
5411 ssh2_pkt_addbool(ssh, 1); /* want reply */
5412 }
5413 ssh2_pkt_send(ssh);
5414 do {
5415 crWaitUntilV(ispkt);
5416 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5417 unsigned i = ssh2_pkt_getuint32(ssh);
5418 struct ssh_channel *c;
5419 c = find234(ssh->channels, &i, ssh_channelfind);
5420 if (!c)
5421 continue; /* nonexistent channel */
5422 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5423 }
5424 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5425 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5426 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5427 bombout((ssh,"Unexpected response to shell/command request:"
5428 " packet type %d", ssh->pktin.type));
5429 crReturnV;
5430 }
5431 /*
5432 * We failed to start the command. If this is the
5433 * fallback command, we really are finished; if it's
5434 * not, and if the fallback command exists, try falling
5435 * back to it before complaining.
5436 */
5437 if (!ssh->fallback_cmd && ssh->cfg.remote_cmd_ptr2 != NULL) {
5438 logevent("Primary command failed; attempting fallback");
5439 ssh->fallback_cmd = TRUE;
5440 continue;
5441 }
5442 bombout((ssh,"Server refused to start a shell/command"));
5443 crReturnV;
5444 } else {
5445 logevent("Started a shell/command");
5446 }
5447 break;
5448 }
5449
5450 ssh->state = SSH_STATE_SESSION;
5451 if (ssh->size_needed)
5452 ssh_size(ssh, ssh->term_width, ssh->term_height);
5453 if (ssh->eof_needed)
5454 ssh_special(ssh, TS_EOF);
5455
5456 /*
5457 * Transfer data!
5458 */
5459 if (ssh->ldisc)
5460 ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */
5461 ssh->send_ok = 1;
5462 while (1) {
5463 crReturnV;
5464 s->try_send = FALSE;
5465 if (ispkt) {
5466 if (ssh->pktin.type == SSH2_MSG_CHANNEL_DATA ||
5467 ssh->pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA) {
5468 char *data;
5469 int length;
5470 unsigned i = ssh2_pkt_getuint32(ssh);
5471 struct ssh_channel *c;
5472 c = find234(ssh->channels, &i, ssh_channelfind);
5473 if (!c)
5474 continue; /* nonexistent channel */
5475 if (ssh->pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
5476 ssh2_pkt_getuint32(ssh) != SSH2_EXTENDED_DATA_STDERR)
5477 continue; /* extended but not stderr */
5478 ssh2_pkt_getstring(ssh, &data, &length);
5479 if (data) {
5480 int bufsize;
5481 c->v.v2.locwindow -= length;
5482 switch (c->type) {
5483 case CHAN_MAINSESSION:
5484 bufsize =
5485 from_backend(ssh->frontend, ssh->pktin.type ==
5486 SSH2_MSG_CHANNEL_EXTENDED_DATA,
5487 data, length);
5488 break;
5489 case CHAN_X11:
5490 bufsize = x11_send(c->u.x11.s, data, length);
5491 break;
5492 case CHAN_SOCKDATA:
5493 bufsize = pfd_send(c->u.pfd.s, data, length);
5494 break;
5495 case CHAN_AGENT:
5496 while (length > 0) {
5497 if (c->u.a.lensofar < 4) {
5498 int l = min(4 - c->u.a.lensofar, length);
5499 memcpy(c->u.a.msglen + c->u.a.lensofar,
5500 data, l);
5501 data += l;
5502 length -= l;
5503 c->u.a.lensofar += l;
5504 }
5505 if (c->u.a.lensofar == 4) {
5506 c->u.a.totallen =
5507 4 + GET_32BIT(c->u.a.msglen);
5508 c->u.a.message = smalloc(c->u.a.totallen);
5509 memcpy(c->u.a.message, c->u.a.msglen, 4);
5510 }
5511 if (c->u.a.lensofar >= 4 && length > 0) {
5512 int l =
5513 min(c->u.a.totallen - c->u.a.lensofar,
5514 length);
5515 memcpy(c->u.a.message + c->u.a.lensofar,
5516 data, l);
5517 data += l;
5518 length -= l;
5519 c->u.a.lensofar += l;
5520 }
5521 if (c->u.a.lensofar == c->u.a.totallen) {
5522 void *reply, *sentreply;
5523 int replylen;
5524 agent_query(c->u.a.message,
5525 c->u.a.totallen, &reply,
5526 &replylen);
5527 if (reply)
5528 sentreply = reply;
5529 else {
5530 /* Fake SSH_AGENT_FAILURE. */
5531 sentreply = "\0\0\0\1\5";
5532 replylen = 5;
5533 }
5534 ssh2_add_channel_data(c, sentreply, replylen);
5535 s->try_send = TRUE;
5536 if (reply)
5537 sfree(reply);
5538 sfree(c->u.a.message);
5539 c->u.a.lensofar = 0;
5540 }
5541 }
5542 bufsize = 0;
5543 break;
5544 }
5545 /*
5546 * If we are not buffering too much data,
5547 * enlarge the window again at the remote side.
5548 */
5549 if (bufsize < OUR_V2_WINSIZE)
5550 ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
5551 }
5552 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_EOF) {
5553 unsigned i = ssh2_pkt_getuint32(ssh);
5554 struct ssh_channel *c;
5555
5556 c = find234(ssh->channels, &i, ssh_channelfind);
5557 if (!c)
5558 continue; /* nonexistent channel */
5559
5560 if (c->type == CHAN_X11) {
5561 /*
5562 * Remote EOF on an X11 channel means we should
5563 * wrap up and close the channel ourselves.
5564 */
5565 x11_close(c->u.x11.s);
5566 sshfwd_close(c);
5567 } else if (c->type == CHAN_AGENT) {
5568 sshfwd_close(c);
5569 } else if (c->type == CHAN_SOCKDATA) {
5570 pfd_close(c->u.pfd.s);
5571 sshfwd_close(c);
5572 }
5573 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_CLOSE) {
5574 unsigned i = ssh2_pkt_getuint32(ssh);
5575 struct ssh_channel *c;
5576
5577 c = find234(ssh->channels, &i, ssh_channelfind);
5578 if (!c || ((int)c->remoteid) == -1) {
5579 bombout((ssh,"Received CHANNEL_CLOSE for %s channel %d\n",
5580 c ? "half-open" : "nonexistent", i));
5581 }
5582 /* Do pre-close processing on the channel. */
5583 switch (c->type) {
5584 case CHAN_MAINSESSION:
5585 break; /* nothing to see here, move along */
5586 case CHAN_X11:
5587 if (c->u.x11.s != NULL)
5588 x11_close(c->u.x11.s);
5589 sshfwd_close(c);
5590 break;
5591 case CHAN_AGENT:
5592 sshfwd_close(c);
5593 break;
5594 case CHAN_SOCKDATA:
5595 if (c->u.pfd.s != NULL)
5596 pfd_close(c->u.pfd.s);
5597 sshfwd_close(c);
5598 break;
5599 }
5600 if (c->closes == 0) {
5601 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
5602 ssh2_pkt_adduint32(ssh, c->remoteid);
5603 ssh2_pkt_send(ssh);
5604 }
5605 del234(ssh->channels, c);
5606 bufchain_clear(&c->v.v2.outbuffer);
5607 sfree(c);
5608
5609 /*
5610 * See if that was the last channel left open.
5611 */
5612 if (count234(ssh->channels) == 0) {
5613 #if 0
5614 /*
5615 * We used to send SSH_MSG_DISCONNECT here,
5616 * because I'd believed that _every_ conforming
5617 * SSH2 connection had to end with a disconnect
5618 * being sent by at least one side; apparently
5619 * I was wrong and it's perfectly OK to
5620 * unceremoniously slam the connection shut
5621 * when you're done, and indeed OpenSSH feels
5622 * this is more polite than sending a
5623 * DISCONNECT. So now we don't.
5624 */
5625 logevent("All channels closed. Disconnecting");
5626 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5627 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5628 ssh2_pkt_addstring(ssh, "All open channels closed");
5629 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5630 ssh2_pkt_send(ssh);
5631 #endif
5632 ssh->state = SSH_STATE_CLOSED;
5633 crReturnV;
5634 }
5635 continue; /* remote sends close; ignore (FIXME) */
5636 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5637 unsigned i = ssh2_pkt_getuint32(ssh);
5638 struct ssh_channel *c;
5639 c = find234(ssh->channels, &i, ssh_channelfind);
5640 if (!c || c->closes)
5641 continue; /* nonexistent or closing channel */
5642 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5643 s->try_send = TRUE;
5644 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
5645 unsigned i = ssh2_pkt_getuint32(ssh);
5646 struct ssh_channel *c;
5647 c = find234(ssh->channels, &i, ssh_channelfind);
5648 if (!c)
5649 continue; /* nonexistent channel */
5650 if (c->type != CHAN_SOCKDATA_DORMANT)
5651 continue; /* dunno why they're confirming this */
5652 c->remoteid = ssh2_pkt_getuint32(ssh);
5653 c->type = CHAN_SOCKDATA;
5654 c->v.v2.remwindow = ssh2_pkt_getuint32(ssh);
5655 c->v.v2.remmaxpkt = ssh2_pkt_getuint32(ssh);
5656 if (c->u.pfd.s)
5657 pfd_confirm(c->u.pfd.s);
5658 if (c->closes) {
5659 /*
5660 * We have a pending close on this channel,
5661 * which we decided on before the server acked
5662 * the channel open. So now we know the
5663 * remoteid, we can close it again.
5664 */
5665 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
5666 ssh2_pkt_adduint32(ssh, c->remoteid);
5667 ssh2_pkt_send(ssh);
5668 }
5669 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN_FAILURE) {
5670 unsigned i = ssh2_pkt_getuint32(ssh);
5671 struct ssh_channel *c;
5672 c = find234(ssh->channels, &i, ssh_channelfind);
5673 if (!c)
5674 continue; /* nonexistent channel */
5675 if (c->type != CHAN_SOCKDATA_DORMANT)
5676 continue; /* dunno why they're failing this */
5677
5678 logevent("Forwarded connection refused by server");
5679
5680 pfd_close(c->u.pfd.s);
5681
5682 del234(ssh->channels, c);
5683 sfree(c);
5684 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_REQUEST) {
5685 unsigned localid;
5686 char *type;
5687 int typelen, want_reply;
5688 struct ssh_channel *c;
5689
5690 localid = ssh2_pkt_getuint32(ssh);
5691 ssh2_pkt_getstring(ssh, &type, &typelen);
5692 want_reply = ssh2_pkt_getbool(ssh);
5693
5694 /*
5695 * First, check that the channel exists. Otherwise,
5696 * we can instantly disconnect with a rude message.
5697 */
5698 c = find234(ssh->channels, &localid, ssh_channelfind);
5699 if (!c) {
5700 char buf[80];
5701 sprintf(buf, "Received channel request for nonexistent"
5702 " channel %d", localid);
5703 logevent(buf);
5704 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5705 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5706 ssh2_pkt_addstring(ssh, buf);
5707 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5708 ssh2_pkt_send(ssh);
5709 connection_fatal("%s", buf);
5710 ssh->state = SSH_STATE_CLOSED;
5711 crReturnV;
5712 }
5713
5714 /*
5715 * Having got the channel number, we now look at
5716 * the request type string to see if it's something
5717 * we recognise.
5718 */
5719 if (typelen == 11 && !memcmp(type, "exit-status", 11) &&
5720 c == ssh->mainchan) {
5721 /* We recognise "exit-status" on the primary channel. */
5722 char buf[100];
5723 ssh->exitcode = ssh2_pkt_getuint32(ssh);
5724 sprintf(buf, "Server sent command exit status %d",
5725 ssh->exitcode);
5726 logevent(buf);
5727 if (want_reply) {
5728 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_SUCCESS);
5729 ssh2_pkt_adduint32(ssh, c->remoteid);
5730 ssh2_pkt_send(ssh);
5731 }
5732 } else {
5733 /*
5734 * This is a channel request we don't know
5735 * about, so we now either ignore the request
5736 * or respond with CHANNEL_FAILURE, depending
5737 * on want_reply.
5738 */
5739 if (want_reply) {
5740 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_FAILURE);
5741 ssh2_pkt_adduint32(ssh, c->remoteid);
5742 ssh2_pkt_send(ssh);
5743 }
5744 }
5745 } else if (ssh->pktin.type == SSH2_MSG_GLOBAL_REQUEST) {
5746 char *type;
5747 int typelen, want_reply;
5748
5749 ssh2_pkt_getstring(ssh, &type, &typelen);
5750 want_reply = ssh2_pkt_getbool(ssh);
5751
5752 /*
5753 * We currently don't support any global requests
5754 * at all, so we either ignore the request or
5755 * respond with REQUEST_FAILURE, depending on
5756 * want_reply.
5757 */
5758 if (want_reply) {
5759 ssh2_pkt_init(ssh, SSH2_MSG_REQUEST_FAILURE);
5760 ssh2_pkt_send(ssh);
5761 }
5762 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN) {
5763 char *type;
5764 int typelen;
5765 char *peeraddr;
5766 int peeraddrlen;
5767 int port;
5768 char *error = NULL;
5769 struct ssh_channel *c;
5770 unsigned remid, winsize, pktsize;
5771 ssh2_pkt_getstring(ssh, &type, &typelen);
5772 c = smalloc(sizeof(struct ssh_channel));
5773 c->ssh = ssh;
5774
5775 remid = ssh2_pkt_getuint32(ssh);
5776 winsize = ssh2_pkt_getuint32(ssh);
5777 pktsize = ssh2_pkt_getuint32(ssh);
5778 ssh2_pkt_getstring(ssh, &peeraddr, &peeraddrlen);
5779 port = ssh2_pkt_getuint32(ssh);
5780
5781 if (typelen == 3 && !memcmp(type, "x11", 3)) {
5782 char *addrstr = smalloc(peeraddrlen+1);
5783 memcpy(addrstr, peeraddr, peeraddrlen);
5784 peeraddr[peeraddrlen] = '\0';
5785
5786 if (!ssh->X11_fwd_enabled)
5787 error = "X11 forwarding is not enabled";
5788 else if (x11_init(&c->u.x11.s, ssh->cfg.x11_display, c,
5789 ssh->x11auth, addrstr, port,
5790 &ssh->cfg) != NULL) {
5791 error = "Unable to open an X11 connection";
5792 } else {
5793 c->type = CHAN_X11;
5794 }
5795
5796 sfree(addrstr);
5797 } else if (typelen == 15 &&
5798 !memcmp(type, "forwarded-tcpip", 15)) {
5799 struct ssh_rportfwd pf, *realpf;
5800 char *dummy;
5801 int dummylen;
5802 ssh2_pkt_getstring(ssh, &dummy, &dummylen);/* skip address */
5803 pf.sport = ssh2_pkt_getuint32(ssh);
5804 realpf = find234(ssh->rportfwds, &pf, NULL);
5805 if (realpf == NULL) {
5806 error = "Remote port is not recognised";
5807 } else {
5808 char *e = pfd_newconnect(&c->u.pfd.s, realpf->dhost,
5809 realpf->dport, c, &ssh->cfg);
5810 logeventf(ssh, "Received remote port open request"
5811 " for %s:%d", realpf->dhost, realpf->dport);
5812 if (e != NULL) {
5813 logeventf(ssh, "Port open failed: %s", e);
5814 error = "Port open failed";
5815 } else {
5816 logevent("Forwarded port opened successfully");
5817 c->type = CHAN_SOCKDATA;
5818 }
5819 }
5820 } else if (typelen == 22 &&
5821 !memcmp(type, "auth-agent@openssh.com", 3)) {
5822 if (!ssh->agentfwd_enabled)
5823 error = "Agent forwarding is not enabled";
5824 else {
5825 c->type = CHAN_AGENT; /* identify channel type */
5826 c->u.a.lensofar = 0;
5827 }
5828 } else {
5829 error = "Unsupported channel type requested";
5830 }
5831
5832 c->remoteid = remid;
5833 if (error) {
5834 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN_FAILURE);
5835 ssh2_pkt_adduint32(ssh, c->remoteid);
5836 ssh2_pkt_adduint32(ssh, SSH2_OPEN_CONNECT_FAILED);
5837 ssh2_pkt_addstring(ssh, error);
5838 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5839 ssh2_pkt_send(ssh);
5840 sfree(c);
5841 } else {
5842 c->localid = alloc_channel_id(ssh);
5843 c->closes = 0;
5844 c->v.v2.locwindow = OUR_V2_WINSIZE;
5845 c->v.v2.remwindow = winsize;
5846 c->v.v2.remmaxpkt = pktsize;
5847 bufchain_init(&c->v.v2.outbuffer);
5848 add234(ssh->channels, c);
5849 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
5850 ssh2_pkt_adduint32(ssh, c->remoteid);
5851 ssh2_pkt_adduint32(ssh, c->localid);
5852 ssh2_pkt_adduint32(ssh, c->v.v2.locwindow);
5853 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
5854 ssh2_pkt_send(ssh);
5855 }
5856 } else {
5857 bombout((ssh,"Strange packet received: type %d", ssh->pktin.type));
5858 crReturnV;
5859 }
5860 } else {
5861 /*
5862 * We have spare data. Add it to the channel buffer.
5863 */
5864 ssh2_add_channel_data(ssh->mainchan, (char *)in, inlen);
5865 s->try_send = TRUE;
5866 }
5867 if (s->try_send) {
5868 int i;
5869 struct ssh_channel *c;
5870 /*
5871 * Try to send data on all channels if we can.
5872 */
5873 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
5874 int bufsize;
5875 if (c->closes)
5876 continue; /* don't send on closing channels */
5877 bufsize = ssh2_try_send(c);
5878 if (bufsize == 0) {
5879 switch (c->type) {
5880 case CHAN_MAINSESSION:
5881 /* stdin need not receive an unthrottle
5882 * notification since it will be polled */
5883 break;
5884 case CHAN_X11:
5885 x11_unthrottle(c->u.x11.s);
5886 break;
5887 case CHAN_AGENT:
5888 /* agent sockets are request/response and need no
5889 * buffer management */
5890 break;
5891 case CHAN_SOCKDATA:
5892 pfd_unthrottle(c->u.pfd.s);
5893 break;
5894 }
5895 }
5896 }
5897 }
5898 }
5899
5900 crFinishV;
5901 }
5902
5903 /*
5904 * Handle the top-level SSH2 protocol.
5905 */
5906 static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
5907 {
5908 if (do_ssh2_transport(ssh, in, inlen, ispkt) == 0)
5909 return;
5910 do_ssh2_authconn(ssh, in, inlen, ispkt);
5911 }
5912
5913 /*
5914 * Called to set up the connection.
5915 *
5916 * Returns an error message, or NULL on success.
5917 */
5918 static char *ssh_init(void *frontend_handle, void **backend_handle,
5919 Config *cfg,
5920 char *host, int port, char **realhost, int nodelay)
5921 {
5922 char *p;
5923 Ssh ssh;
5924
5925 ssh = smalloc(sizeof(*ssh));
5926 ssh->cfg = *cfg; /* STRUCTURE COPY */
5927 ssh->s = NULL;
5928 ssh->cipher = NULL;
5929 ssh->v1_cipher_ctx = NULL;
5930 ssh->crcda_ctx = NULL;
5931 ssh->cscipher = NULL;
5932 ssh->cs_cipher_ctx = NULL;
5933 ssh->sccipher = NULL;
5934 ssh->sc_cipher_ctx = NULL;
5935 ssh->csmac = NULL;
5936 ssh->cs_mac_ctx = NULL;
5937 ssh->scmac = NULL;
5938 ssh->sc_mac_ctx = NULL;
5939 ssh->cscomp = NULL;
5940 ssh->cs_comp_ctx = NULL;
5941 ssh->sccomp = NULL;
5942 ssh->sc_comp_ctx = NULL;
5943 ssh->kex = NULL;
5944 ssh->kex_ctx = NULL;
5945 ssh->hostkey = NULL;
5946 ssh->exitcode = -1;
5947 ssh->state = SSH_STATE_PREPACKET;
5948 ssh->size_needed = FALSE;
5949 ssh->eof_needed = FALSE;
5950 ssh->ldisc = NULL;
5951 ssh->logctx = NULL;
5952 {
5953 static const struct Packet empty = { 0, 0, NULL, NULL, 0 };
5954 ssh->pktin = ssh->pktout = empty;
5955 }
5956 ssh->deferred_send_data = NULL;
5957 ssh->deferred_len = 0;
5958 ssh->deferred_size = 0;
5959 ssh->fallback_cmd = 0;
5960 ssh->pkt_ctx = 0;
5961 ssh->x11auth = NULL;
5962 ssh->v1_compressing = FALSE;
5963 ssh->v2_outgoing_sequence = 0;
5964 ssh->ssh1_rdpkt_crstate = 0;
5965 ssh->ssh2_rdpkt_crstate = 0;
5966 ssh->do_ssh_init_crstate = 0;
5967 ssh->ssh_gotdata_crstate = 0;
5968 ssh->ssh1_protocol_crstate = 0;
5969 ssh->do_ssh1_login_crstate = 0;
5970 ssh->do_ssh2_transport_crstate = 0;
5971 ssh->do_ssh2_authconn_crstate = 0;
5972 ssh->do_ssh_init_state = NULL;
5973 ssh->do_ssh1_login_state = NULL;
5974 ssh->do_ssh2_transport_state = NULL;
5975 ssh->do_ssh2_authconn_state = NULL;
5976 ssh->mainchan = NULL;
5977 ssh->throttled_all = 0;
5978 ssh->v1_stdout_throttling = 0;
5979
5980 *backend_handle = ssh;
5981
5982 #ifdef MSCRYPTOAPI
5983 if (crypto_startup() == 0)
5984 return "Microsoft high encryption pack not installed!";
5985 #endif
5986
5987 ssh->frontend = frontend_handle;
5988 ssh->term_width = ssh->cfg.width;
5989 ssh->term_height = ssh->cfg.height;
5990
5991 ssh->channels = NULL;
5992 ssh->rportfwds = NULL;
5993
5994 ssh->send_ok = 0;
5995 ssh->editing = 0;
5996 ssh->echoing = 0;
5997 ssh->v1_throttle_count = 0;
5998 ssh->overall_bufsize = 0;
5999 ssh->fallback_cmd = 0;
6000
6001 ssh->protocol = NULL;
6002
6003 p = connect_to_host(ssh, host, port, realhost, nodelay);
6004 if (p != NULL)
6005 return p;
6006
6007 return NULL;
6008 }
6009
6010 static void ssh_free(void *handle)
6011 {
6012 Ssh ssh = (Ssh) handle;
6013 struct ssh_channel *c;
6014 struct ssh_rportfwd *pf;
6015
6016 if (ssh->v1_cipher_ctx)
6017 ssh->cipher->free_context(ssh->v1_cipher_ctx);
6018 if (ssh->cs_cipher_ctx)
6019 ssh->cscipher->free_context(ssh->cs_cipher_ctx);
6020 if (ssh->sc_cipher_ctx)
6021 ssh->sccipher->free_context(ssh->sc_cipher_ctx);
6022 if (ssh->cs_mac_ctx)
6023 ssh->csmac->free_context(ssh->cs_mac_ctx);
6024 if (ssh->sc_mac_ctx)
6025 ssh->scmac->free_context(ssh->sc_mac_ctx);
6026 if (ssh->cs_comp_ctx)
6027 ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
6028 if (ssh->sc_comp_ctx)
6029 ssh->sccomp->compress_cleanup(ssh->sc_comp_ctx);
6030 if (ssh->kex_ctx)
6031 dh_cleanup(ssh->kex_ctx);
6032 sfree(ssh->savedhost);
6033
6034 if (ssh->channels) {
6035 while ((c = delpos234(ssh->channels, 0)) != NULL) {
6036 switch (c->type) {
6037 case CHAN_X11:
6038 if (c->u.x11.s != NULL)
6039 x11_close(c->u.x11.s);
6040 break;
6041 case CHAN_SOCKDATA:
6042 if (c->u.pfd.s != NULL)
6043 pfd_close(c->u.pfd.s);
6044 break;
6045 }
6046 sfree(c);
6047 }
6048 freetree234(ssh->channels);
6049 }
6050
6051 if (ssh->rportfwds) {
6052 while ((pf = delpos234(ssh->rportfwds, 0)) != NULL)
6053 sfree(pf);
6054 freetree234(ssh->rportfwds);
6055 }
6056 sfree(ssh->deferred_send_data);
6057 if (ssh->x11auth)
6058 x11_free_auth(ssh->x11auth);
6059 sfree(ssh->do_ssh_init_state);
6060 sfree(ssh->do_ssh1_login_state);
6061 sfree(ssh->do_ssh2_transport_state);
6062 sfree(ssh->do_ssh2_authconn_state);
6063
6064 if (ssh->s)
6065 sk_close(ssh->s);
6066 sfree(ssh);
6067 }
6068
6069 /*
6070 * Reconfigure the SSH backend.
6071 *
6072 * Currently, this function does nothing very useful. In future,
6073 * however, we could do some handy things with it. For example, we
6074 * could make the port forwarding configurer active in the Change
6075 * Settings box, and this routine could close down existing
6076 * forwardings and open up new ones in response to changes.
6077 */
6078 static void ssh_reconfig(void *handle, Config *cfg)
6079 {
6080 Ssh ssh = (Ssh) handle;
6081 ssh->cfg = *cfg; /* STRUCTURE COPY */
6082 }
6083
6084 /*
6085 * Called to send data down the Telnet connection.
6086 */
6087 static int ssh_send(void *handle, char *buf, int len)
6088 {
6089 Ssh ssh = (Ssh) handle;
6090
6091 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
6092 return 0;
6093
6094 ssh->protocol(ssh, (unsigned char *)buf, len, 0);
6095
6096 return ssh_sendbuffer(ssh);
6097 }
6098
6099 /*
6100 * Called to query the current amount of buffered stdin data.
6101 */
6102 static int ssh_sendbuffer(void *handle)
6103 {
6104 Ssh ssh = (Ssh) handle;
6105 int override_value;
6106
6107 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
6108 return 0;
6109
6110 /*
6111 * If the SSH socket itself has backed up, add the total backup
6112 * size on that to any individual buffer on the stdin channel.
6113 */
6114 override_value = 0;
6115 if (ssh->throttled_all)
6116 override_value = ssh->overall_bufsize;
6117
6118 if (ssh->version == 1) {
6119 return override_value;
6120 } else if (ssh->version == 2) {
6121 if (!ssh->mainchan || ssh->mainchan->closes > 0)
6122 return override_value;
6123 else
6124 return (override_value +
6125 bufchain_size(&ssh->mainchan->v.v2.outbuffer));
6126 }
6127
6128 return 0;
6129 }
6130
6131 /*
6132 * Called to set the size of the window from SSH's POV.
6133 */
6134 static void ssh_size(void *handle, int width, int height)
6135 {
6136 Ssh ssh = (Ssh) handle;
6137
6138 ssh->term_width = width;
6139 ssh->term_height = height;
6140
6141 switch (ssh->state) {
6142 case SSH_STATE_BEFORE_SIZE:
6143 case SSH_STATE_PREPACKET:
6144 case SSH_STATE_CLOSED:
6145 break; /* do nothing */
6146 case SSH_STATE_INTERMED:
6147 ssh->size_needed = TRUE; /* buffer for later */
6148 break;
6149 case SSH_STATE_SESSION:
6150 if (!ssh->cfg.nopty) {
6151 if (ssh->version == 1) {
6152 send_packet(ssh, SSH1_CMSG_WINDOW_SIZE,
6153 PKT_INT, ssh->term_height,
6154 PKT_INT, ssh->term_width,
6155 PKT_INT, 0, PKT_INT, 0, PKT_END);
6156 } else {
6157 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
6158 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
6159 ssh2_pkt_addstring(ssh, "window-change");
6160 ssh2_pkt_addbool(ssh, 0);
6161 ssh2_pkt_adduint32(ssh, ssh->term_width);
6162 ssh2_pkt_adduint32(ssh, ssh->term_height);
6163 ssh2_pkt_adduint32(ssh, 0);
6164 ssh2_pkt_adduint32(ssh, 0);
6165 ssh2_pkt_send(ssh);
6166 }
6167 }
6168 break;
6169 }
6170 }
6171
6172 /*
6173 * Send Telnet special codes. TS_EOF is useful for `plink', so you
6174 * can send an EOF and collect resulting output (e.g. `plink
6175 * hostname sort').
6176 */
6177 static void ssh_special(void *handle, Telnet_Special code)
6178 {
6179 Ssh ssh = (Ssh) handle;
6180
6181 if (code == TS_EOF) {
6182 if (ssh->state != SSH_STATE_SESSION) {
6183 /*
6184 * Buffer the EOF in case we are pre-SESSION, so we can
6185 * send it as soon as we reach SESSION.
6186 */
6187 if (code == TS_EOF)
6188 ssh->eof_needed = TRUE;
6189 return;
6190 }
6191 if (ssh->version == 1) {
6192 send_packet(ssh, SSH1_CMSG_EOF, PKT_END);
6193 } else {
6194 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_EOF);
6195 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
6196 ssh2_pkt_send(ssh);
6197 }
6198 logevent("Sent EOF message");
6199 } else if (code == TS_PING) {
6200 if (ssh->state == SSH_STATE_CLOSED
6201 || ssh->state == SSH_STATE_PREPACKET) return;
6202 if (ssh->version == 1) {
6203 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE))
6204 send_packet(ssh, SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
6205 } else {
6206 ssh2_pkt_init(ssh, SSH2_MSG_IGNORE);
6207 ssh2_pkt_addstring_start(ssh);
6208 ssh2_pkt_send(ssh);
6209 }
6210 } else {
6211 /* do nothing */
6212 }
6213 }
6214
6215 void *new_sock_channel(void *handle, Socket s)
6216 {
6217 Ssh ssh = (Ssh) handle;
6218 struct ssh_channel *c;
6219 c = smalloc(sizeof(struct ssh_channel));
6220 c->ssh = ssh;
6221
6222 if (c) {
6223 c->remoteid = -1; /* to be set when open confirmed */
6224 c->localid = alloc_channel_id(ssh);
6225 c->closes = 0;
6226 c->type = CHAN_SOCKDATA_DORMANT;/* identify channel type */
6227 c->u.pfd.s = s;
6228 bufchain_init(&c->v.v2.outbuffer);
6229 add234(ssh->channels, c);
6230 }
6231 return c;
6232 }
6233
6234 /*
6235 * This is called when stdout/stderr (the entity to which
6236 * from_backend sends data) manages to clear some backlog.
6237 */
6238 static void ssh_unthrottle(void *handle, int bufsize)
6239 {
6240 Ssh ssh = (Ssh) handle;
6241 if (ssh->version == 1) {
6242 if (ssh->v1_stdout_throttling && bufsize < SSH1_BUFFER_LIMIT) {
6243 ssh->v1_stdout_throttling = 0;
6244 ssh1_throttle(ssh, -1);
6245 }
6246 } else {
6247 if (ssh->mainchan && ssh->mainchan->closes == 0)
6248 ssh2_set_window(ssh->mainchan, OUR_V2_WINSIZE - bufsize);
6249 }
6250 }
6251
6252 void ssh_send_port_open(void *channel, char *hostname, int port, char *org)
6253 {
6254 struct ssh_channel *c = (struct ssh_channel *)channel;
6255 Ssh ssh = c->ssh;
6256
6257 logeventf(ssh, "Opening forwarded connection to %s:%d", hostname, port);
6258
6259 if (ssh->version == 1) {
6260 send_packet(ssh, SSH1_MSG_PORT_OPEN,
6261 PKT_INT, c->localid,
6262 PKT_STR, hostname,
6263 PKT_INT, port,
6264 //PKT_STR, <org:orgport>,
6265 PKT_END);
6266 } else {
6267 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN);
6268 ssh2_pkt_addstring(ssh, "direct-tcpip");
6269 ssh2_pkt_adduint32(ssh, c->localid);
6270 c->v.v2.locwindow = OUR_V2_WINSIZE;
6271 ssh2_pkt_adduint32(ssh, c->v.v2.locwindow);/* our window size */
6272 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
6273 ssh2_pkt_addstring(ssh, hostname);
6274 ssh2_pkt_adduint32(ssh, port);
6275 /*
6276 * We make up values for the originator data; partly it's
6277 * too much hassle to keep track, and partly I'm not
6278 * convinced the server should be told details like that
6279 * about my local network configuration.
6280 */
6281 ssh2_pkt_addstring(ssh, "client-side-connection");
6282 ssh2_pkt_adduint32(ssh, 0);
6283 ssh2_pkt_send(ssh);
6284 }
6285 }
6286
6287
6288 static Socket ssh_socket(void *handle)
6289 {
6290 Ssh ssh = (Ssh) handle;
6291 return ssh->s;
6292 }
6293
6294 static int ssh_sendok(void *handle)
6295 {
6296 Ssh ssh = (Ssh) handle;
6297 return ssh->send_ok;
6298 }
6299
6300 static int ssh_ldisc(void *handle, int option)
6301 {
6302 Ssh ssh = (Ssh) handle;
6303 if (option == LD_ECHO)
6304 return ssh->echoing;
6305 if (option == LD_EDIT)
6306 return ssh->editing;
6307 return FALSE;
6308 }
6309
6310 static void ssh_provide_ldisc(void *handle, void *ldisc)
6311 {
6312 Ssh ssh = (Ssh) handle;
6313 ssh->ldisc = ldisc;
6314 }
6315
6316 static void ssh_provide_logctx(void *handle, void *logctx)
6317 {
6318 Ssh ssh = (Ssh) handle;
6319 ssh->logctx = logctx;
6320 }
6321
6322 static int ssh_return_exitcode(void *handle)
6323 {
6324 Ssh ssh = (Ssh) handle;
6325 return ssh->exitcode;
6326 }
6327
6328 /*
6329 * Gross hack: pscp will try to start SFTP but fall back to scp1 if
6330 * that fails. This variable is the means by which scp.c can reach
6331 * into the SSH code and find out which one it got.
6332 */
6333 extern int ssh_fallback_cmd(void *handle)
6334 {
6335 Ssh ssh = (Ssh) handle;
6336 return ssh->fallback_cmd;
6337 }
6338
6339 Backend ssh_backend = {
6340 ssh_init,
6341 ssh_free,
6342 ssh_reconfig,
6343 ssh_send,
6344 ssh_sendbuffer,
6345 ssh_size,
6346 ssh_special,
6347 ssh_socket,
6348 ssh_return_exitcode,
6349 ssh_sendok,
6350 ssh_ldisc,
6351 ssh_provide_ldisc,
6352 ssh_provide_logctx,
6353 ssh_unthrottle,
6354 22
6355 };
Local modifications for Simon Tatham's `PuTTY' SSH client and terminal emulator