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dde5bfabbfe67c233357c22f8629eca8ed681957
[u/mdw/putty] / ssh.c
1 #include <stdio.h>
2 #include <stdlib.h>
3 #include <stdarg.h>
4 #include <assert.h>
5
6 #include "putty.h"
7 #include "tree234.h"
8 #include "ssh.h"
9
10 #ifndef FALSE
11 #define FALSE 0
12 #endif
13 #ifndef TRUE
14 #define TRUE 1
15 #endif
16
17 #define SSH1_MSG_DISCONNECT 1 /* 0x1 */
18 #define SSH1_SMSG_PUBLIC_KEY 2 /* 0x2 */
19 #define SSH1_CMSG_SESSION_KEY 3 /* 0x3 */
20 #define SSH1_CMSG_USER 4 /* 0x4 */
21 #define SSH1_CMSG_AUTH_RSA 6 /* 0x6 */
22 #define SSH1_SMSG_AUTH_RSA_CHALLENGE 7 /* 0x7 */
23 #define SSH1_CMSG_AUTH_RSA_RESPONSE 8 /* 0x8 */
24 #define SSH1_CMSG_AUTH_PASSWORD 9 /* 0x9 */
25 #define SSH1_CMSG_REQUEST_PTY 10 /* 0xa */
26 #define SSH1_CMSG_WINDOW_SIZE 11 /* 0xb */
27 #define SSH1_CMSG_EXEC_SHELL 12 /* 0xc */
28 #define SSH1_CMSG_EXEC_CMD 13 /* 0xd */
29 #define SSH1_SMSG_SUCCESS 14 /* 0xe */
30 #define SSH1_SMSG_FAILURE 15 /* 0xf */
31 #define SSH1_CMSG_STDIN_DATA 16 /* 0x10 */
32 #define SSH1_SMSG_STDOUT_DATA 17 /* 0x11 */
33 #define SSH1_SMSG_STDERR_DATA 18 /* 0x12 */
34 #define SSH1_CMSG_EOF 19 /* 0x13 */
35 #define SSH1_SMSG_EXIT_STATUS 20 /* 0x14 */
36 #define SSH1_MSG_CHANNEL_OPEN_CONFIRMATION 21 /* 0x15 */
37 #define SSH1_MSG_CHANNEL_OPEN_FAILURE 22 /* 0x16 */
38 #define SSH1_MSG_CHANNEL_DATA 23 /* 0x17 */
39 #define SSH1_MSG_CHANNEL_CLOSE 24 /* 0x18 */
40 #define SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION 25 /* 0x19 */
41 #define SSH1_SMSG_X11_OPEN 27 /* 0x1b */
42 #define SSH1_CMSG_PORT_FORWARD_REQUEST 28 /* 0x1c */
43 #define SSH1_MSG_PORT_OPEN 29 /* 0x1d */
44 #define SSH1_CMSG_AGENT_REQUEST_FORWARDING 30 /* 0x1e */
45 #define SSH1_SMSG_AGENT_OPEN 31 /* 0x1f */
46 #define SSH1_MSG_IGNORE 32 /* 0x20 */
47 #define SSH1_CMSG_EXIT_CONFIRMATION 33 /* 0x21 */
48 #define SSH1_CMSG_X11_REQUEST_FORWARDING 34 /* 0x22 */
49 #define SSH1_CMSG_AUTH_RHOSTS_RSA 35 /* 0x23 */
50 #define SSH1_MSG_DEBUG 36 /* 0x24 */
51 #define SSH1_CMSG_REQUEST_COMPRESSION 37 /* 0x25 */
52 #define SSH1_CMSG_AUTH_TIS 39 /* 0x27 */
53 #define SSH1_SMSG_AUTH_TIS_CHALLENGE 40 /* 0x28 */
54 #define SSH1_CMSG_AUTH_TIS_RESPONSE 41 /* 0x29 */
55 #define SSH1_CMSG_AUTH_CCARD 70 /* 0x46 */
56 #define SSH1_SMSG_AUTH_CCARD_CHALLENGE 71 /* 0x47 */
57 #define SSH1_CMSG_AUTH_CCARD_RESPONSE 72 /* 0x48 */
58
59 #define SSH1_AUTH_TIS 5 /* 0x5 */
60 #define SSH1_AUTH_CCARD 16 /* 0x10 */
61
62 #define SSH1_PROTOFLAG_SCREEN_NUMBER 1 /* 0x1 */
63 /* Mask for protoflags we will echo back to server if seen */
64 #define SSH1_PROTOFLAGS_SUPPORTED 0 /* 0x1 */
65
66 #define SSH2_MSG_DISCONNECT 1 /* 0x1 */
67 #define SSH2_MSG_IGNORE 2 /* 0x2 */
68 #define SSH2_MSG_UNIMPLEMENTED 3 /* 0x3 */
69 #define SSH2_MSG_DEBUG 4 /* 0x4 */
70 #define SSH2_MSG_SERVICE_REQUEST 5 /* 0x5 */
71 #define SSH2_MSG_SERVICE_ACCEPT 6 /* 0x6 */
72 #define SSH2_MSG_KEXINIT 20 /* 0x14 */
73 #define SSH2_MSG_NEWKEYS 21 /* 0x15 */
74 #define SSH2_MSG_KEXDH_INIT 30 /* 0x1e */
75 #define SSH2_MSG_KEXDH_REPLY 31 /* 0x1f */
76 #define SSH2_MSG_KEX_DH_GEX_REQUEST 30 /* 0x1e */
77 #define SSH2_MSG_KEX_DH_GEX_GROUP 31 /* 0x1f */
78 #define SSH2_MSG_KEX_DH_GEX_INIT 32 /* 0x20 */
79 #define SSH2_MSG_KEX_DH_GEX_REPLY 33 /* 0x21 */
80 #define SSH2_MSG_USERAUTH_REQUEST 50 /* 0x32 */
81 #define SSH2_MSG_USERAUTH_FAILURE 51 /* 0x33 */
82 #define SSH2_MSG_USERAUTH_SUCCESS 52 /* 0x34 */
83 #define SSH2_MSG_USERAUTH_BANNER 53 /* 0x35 */
84 #define SSH2_MSG_USERAUTH_PK_OK 60 /* 0x3c */
85 #define SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ 60 /* 0x3c */
86 #define SSH2_MSG_USERAUTH_INFO_REQUEST 60 /* 0x3c */
87 #define SSH2_MSG_USERAUTH_INFO_RESPONSE 61 /* 0x3d */
88 #define SSH2_MSG_GLOBAL_REQUEST 80 /* 0x50 */
89 #define SSH2_MSG_REQUEST_SUCCESS 81 /* 0x51 */
90 #define SSH2_MSG_REQUEST_FAILURE 82 /* 0x52 */
91 #define SSH2_MSG_CHANNEL_OPEN 90 /* 0x5a */
92 #define SSH2_MSG_CHANNEL_OPEN_CONFIRMATION 91 /* 0x5b */
93 #define SSH2_MSG_CHANNEL_OPEN_FAILURE 92 /* 0x5c */
94 #define SSH2_MSG_CHANNEL_WINDOW_ADJUST 93 /* 0x5d */
95 #define SSH2_MSG_CHANNEL_DATA 94 /* 0x5e */
96 #define SSH2_MSG_CHANNEL_EXTENDED_DATA 95 /* 0x5f */
97 #define SSH2_MSG_CHANNEL_EOF 96 /* 0x60 */
98 #define SSH2_MSG_CHANNEL_CLOSE 97 /* 0x61 */
99 #define SSH2_MSG_CHANNEL_REQUEST 98 /* 0x62 */
100 #define SSH2_MSG_CHANNEL_SUCCESS 99 /* 0x63 */
101 #define SSH2_MSG_CHANNEL_FAILURE 100 /* 0x64 */
102
103 /*
104 * Packet type contexts, so that ssh2_pkt_type can correctly decode
105 * the ambiguous type numbers back into the correct type strings.
106 */
107 #define SSH2_PKTCTX_DHGROUP1 0x0001
108 #define SSH2_PKTCTX_DHGEX 0x0002
109 #define SSH2_PKTCTX_PUBLICKEY 0x0010
110 #define SSH2_PKTCTX_PASSWORD 0x0020
111 #define SSH2_PKTCTX_KBDINTER 0x0040
112 #define SSH2_PKTCTX_AUTH_MASK 0x00F0
113
114 #define SSH2_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT 1 /* 0x1 */
115 #define SSH2_DISCONNECT_PROTOCOL_ERROR 2 /* 0x2 */
116 #define SSH2_DISCONNECT_KEY_EXCHANGE_FAILED 3 /* 0x3 */
117 #define SSH2_DISCONNECT_HOST_AUTHENTICATION_FAILED 4 /* 0x4 */
118 #define SSH2_DISCONNECT_MAC_ERROR 5 /* 0x5 */
119 #define SSH2_DISCONNECT_COMPRESSION_ERROR 6 /* 0x6 */
120 #define SSH2_DISCONNECT_SERVICE_NOT_AVAILABLE 7 /* 0x7 */
121 #define SSH2_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED 8 /* 0x8 */
122 #define SSH2_DISCONNECT_HOST_KEY_NOT_VERIFIABLE 9 /* 0x9 */
123 #define SSH2_DISCONNECT_CONNECTION_LOST 10 /* 0xa */
124 #define SSH2_DISCONNECT_BY_APPLICATION 11 /* 0xb */
125 #define SSH2_DISCONNECT_TOO_MANY_CONNECTIONS 12 /* 0xc */
126 #define SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER 13 /* 0xd */
127 #define SSH2_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE 14 /* 0xe */
128 #define SSH2_DISCONNECT_ILLEGAL_USER_NAME 15 /* 0xf */
129
130 static const char *const ssh2_disconnect_reasons[] = {
131 NULL,
132 "SSH_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT",
133 "SSH_DISCONNECT_PROTOCOL_ERROR",
134 "SSH_DISCONNECT_KEY_EXCHANGE_FAILED",
135 "SSH_DISCONNECT_HOST_AUTHENTICATION_FAILED",
136 "SSH_DISCONNECT_MAC_ERROR",
137 "SSH_DISCONNECT_COMPRESSION_ERROR",
138 "SSH_DISCONNECT_SERVICE_NOT_AVAILABLE",
139 "SSH_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED",
140 "SSH_DISCONNECT_HOST_KEY_NOT_VERIFIABLE",
141 "SSH_DISCONNECT_CONNECTION_LOST",
142 "SSH_DISCONNECT_BY_APPLICATION",
143 "SSH_DISCONNECT_TOO_MANY_CONNECTIONS",
144 "SSH_DISCONNECT_AUTH_CANCELLED_BY_USER",
145 "SSH_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE",
146 "SSH_DISCONNECT_ILLEGAL_USER_NAME",
147 };
148
149 #define SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED 1 /* 0x1 */
150 #define SSH2_OPEN_CONNECT_FAILED 2 /* 0x2 */
151 #define SSH2_OPEN_UNKNOWN_CHANNEL_TYPE 3 /* 0x3 */
152 #define SSH2_OPEN_RESOURCE_SHORTAGE 4 /* 0x4 */
153
154 #define SSH2_EXTENDED_DATA_STDERR 1 /* 0x1 */
155
156 /*
157 * Various remote-bug flags.
158 */
159 #define BUG_CHOKES_ON_SSH1_IGNORE 1
160 #define BUG_SSH2_HMAC 2
161 #define BUG_NEEDS_SSH1_PLAIN_PASSWORD 4
162 #define BUG_CHOKES_ON_RSA 8
163 #define BUG_SSH2_RSA_PADDING 16
164 #define BUG_SSH2_DERIVEKEY 32
165 #define BUG_SSH2_DH_GEX 64
166
167 #define translate(x) if (type == x) return #x
168 #define translatec(x,ctx) if (type == x && (pkt_ctx & ctx)) return #x
169 static char *ssh1_pkt_type(int type)
170 {
171 translate(SSH1_MSG_DISCONNECT);
172 translate(SSH1_SMSG_PUBLIC_KEY);
173 translate(SSH1_CMSG_SESSION_KEY);
174 translate(SSH1_CMSG_USER);
175 translate(SSH1_CMSG_AUTH_RSA);
176 translate(SSH1_SMSG_AUTH_RSA_CHALLENGE);
177 translate(SSH1_CMSG_AUTH_RSA_RESPONSE);
178 translate(SSH1_CMSG_AUTH_PASSWORD);
179 translate(SSH1_CMSG_REQUEST_PTY);
180 translate(SSH1_CMSG_WINDOW_SIZE);
181 translate(SSH1_CMSG_EXEC_SHELL);
182 translate(SSH1_CMSG_EXEC_CMD);
183 translate(SSH1_SMSG_SUCCESS);
184 translate(SSH1_SMSG_FAILURE);
185 translate(SSH1_CMSG_STDIN_DATA);
186 translate(SSH1_SMSG_STDOUT_DATA);
187 translate(SSH1_SMSG_STDERR_DATA);
188 translate(SSH1_CMSG_EOF);
189 translate(SSH1_SMSG_EXIT_STATUS);
190 translate(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION);
191 translate(SSH1_MSG_CHANNEL_OPEN_FAILURE);
192 translate(SSH1_MSG_CHANNEL_DATA);
193 translate(SSH1_MSG_CHANNEL_CLOSE);
194 translate(SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION);
195 translate(SSH1_SMSG_X11_OPEN);
196 translate(SSH1_CMSG_PORT_FORWARD_REQUEST);
197 translate(SSH1_MSG_PORT_OPEN);
198 translate(SSH1_CMSG_AGENT_REQUEST_FORWARDING);
199 translate(SSH1_SMSG_AGENT_OPEN);
200 translate(SSH1_MSG_IGNORE);
201 translate(SSH1_CMSG_EXIT_CONFIRMATION);
202 translate(SSH1_CMSG_X11_REQUEST_FORWARDING);
203 translate(SSH1_CMSG_AUTH_RHOSTS_RSA);
204 translate(SSH1_MSG_DEBUG);
205 translate(SSH1_CMSG_REQUEST_COMPRESSION);
206 translate(SSH1_CMSG_AUTH_TIS);
207 translate(SSH1_SMSG_AUTH_TIS_CHALLENGE);
208 translate(SSH1_CMSG_AUTH_TIS_RESPONSE);
209 translate(SSH1_CMSG_AUTH_CCARD);
210 translate(SSH1_SMSG_AUTH_CCARD_CHALLENGE);
211 translate(SSH1_CMSG_AUTH_CCARD_RESPONSE);
212 return "unknown";
213 }
214 static char *ssh2_pkt_type(int pkt_ctx, int type)
215 {
216 translate(SSH2_MSG_DISCONNECT);
217 translate(SSH2_MSG_IGNORE);
218 translate(SSH2_MSG_UNIMPLEMENTED);
219 translate(SSH2_MSG_DEBUG);
220 translate(SSH2_MSG_SERVICE_REQUEST);
221 translate(SSH2_MSG_SERVICE_ACCEPT);
222 translate(SSH2_MSG_KEXINIT);
223 translate(SSH2_MSG_NEWKEYS);
224 translatec(SSH2_MSG_KEXDH_INIT, SSH2_PKTCTX_DHGROUP1);
225 translatec(SSH2_MSG_KEXDH_REPLY, SSH2_PKTCTX_DHGROUP1);
226 translatec(SSH2_MSG_KEX_DH_GEX_REQUEST, SSH2_PKTCTX_DHGEX);
227 translatec(SSH2_MSG_KEX_DH_GEX_GROUP, SSH2_PKTCTX_DHGEX);
228 translatec(SSH2_MSG_KEX_DH_GEX_INIT, SSH2_PKTCTX_DHGEX);
229 translatec(SSH2_MSG_KEX_DH_GEX_REPLY, SSH2_PKTCTX_DHGEX);
230 translate(SSH2_MSG_USERAUTH_REQUEST);
231 translate(SSH2_MSG_USERAUTH_FAILURE);
232 translate(SSH2_MSG_USERAUTH_SUCCESS);
233 translate(SSH2_MSG_USERAUTH_BANNER);
234 translatec(SSH2_MSG_USERAUTH_PK_OK, SSH2_PKTCTX_PUBLICKEY);
235 translatec(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, SSH2_PKTCTX_PASSWORD);
236 translatec(SSH2_MSG_USERAUTH_INFO_REQUEST, SSH2_PKTCTX_KBDINTER);
237 translatec(SSH2_MSG_USERAUTH_INFO_RESPONSE, SSH2_PKTCTX_KBDINTER);
238 translate(SSH2_MSG_GLOBAL_REQUEST);
239 translate(SSH2_MSG_REQUEST_SUCCESS);
240 translate(SSH2_MSG_REQUEST_FAILURE);
241 translate(SSH2_MSG_CHANNEL_OPEN);
242 translate(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
243 translate(SSH2_MSG_CHANNEL_OPEN_FAILURE);
244 translate(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
245 translate(SSH2_MSG_CHANNEL_DATA);
246 translate(SSH2_MSG_CHANNEL_EXTENDED_DATA);
247 translate(SSH2_MSG_CHANNEL_EOF);
248 translate(SSH2_MSG_CHANNEL_CLOSE);
249 translate(SSH2_MSG_CHANNEL_REQUEST);
250 translate(SSH2_MSG_CHANNEL_SUCCESS);
251 translate(SSH2_MSG_CHANNEL_FAILURE);
252 return "unknown";
253 }
254 #undef translate
255 #undef translatec
256
257 #define GET_32BIT(cp) \
258 (((unsigned long)(unsigned char)(cp)[0] << 24) | \
259 ((unsigned long)(unsigned char)(cp)[1] << 16) | \
260 ((unsigned long)(unsigned char)(cp)[2] << 8) | \
261 ((unsigned long)(unsigned char)(cp)[3]))
262
263 #define PUT_32BIT(cp, value) { \
264 (cp)[0] = (unsigned char)((value) >> 24); \
265 (cp)[1] = (unsigned char)((value) >> 16); \
266 (cp)[2] = (unsigned char)((value) >> 8); \
267 (cp)[3] = (unsigned char)(value); }
268
269 enum { PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR, PKT_BIGNUM };
270
271 /* Coroutine mechanics for the sillier bits of the code */
272 #define crBegin(v) { int *crLine = &v; switch(v) { case 0:;
273 #define crState(t) \
274 struct t *s; \
275 if (!ssh->t) ssh->t = smalloc(sizeof(struct t)); \
276 s = ssh->t;
277 #define crFinish(z) } *crLine = 0; return (z); }
278 #define crFinishV } *crLine = 0; return; }
279 #define crReturn(z) \
280 do {\
281 *crLine =__LINE__; return (z); case __LINE__:;\
282 } while (0)
283 #define crReturnV \
284 do {\
285 *crLine=__LINE__; return; case __LINE__:;\
286 } while (0)
287 #define crStop(z) do{ *crLine = 0; return (z); }while(0)
288 #define crStopV do{ *crLine = 0; return; }while(0)
289 #define crWaitUntil(c) do { crReturn(0); } while (!(c))
290 #define crWaitUntilV(c) do { crReturnV; } while (!(c))
291
292 typedef struct ssh_tag *Ssh;
293
294 static void ssh2_pkt_init(Ssh, int pkt_type);
295 static void ssh2_pkt_addbool(Ssh, unsigned char value);
296 static void ssh2_pkt_adduint32(Ssh, unsigned long value);
297 static void ssh2_pkt_addstring_start(Ssh);
298 static void ssh2_pkt_addstring_str(Ssh, char *data);
299 static void ssh2_pkt_addstring_data(Ssh, char *data, int len);
300 static void ssh2_pkt_addstring(Ssh, char *data);
301 static unsigned char *ssh2_mpint_fmt(Bignum b, int *len);
302 static void ssh2_pkt_addmp(Ssh, Bignum b);
303 static int ssh2_pkt_construct(Ssh);
304 static void ssh2_pkt_send(Ssh);
305
306 /*
307 * Buffer management constants. There are several of these for
308 * various different purposes:
309 *
310 * - SSH1_BUFFER_LIMIT is the amount of backlog that must build up
311 * on a local data stream before we throttle the whole SSH
312 * connection (in SSH1 only). Throttling the whole connection is
313 * pretty drastic so we set this high in the hope it won't
314 * happen very often.
315 *
316 * - SSH_MAX_BACKLOG is the amount of backlog that must build up
317 * on the SSH connection itself before we defensively throttle
318 * _all_ local data streams. This is pretty drastic too (though
319 * thankfully unlikely in SSH2 since the window mechanism should
320 * ensure that the server never has any need to throttle its end
321 * of the connection), so we set this high as well.
322 *
323 * - OUR_V2_WINSIZE is the maximum window size we present on SSH2
324 * channels.
325 */
326
327 #define SSH1_BUFFER_LIMIT 32768
328 #define SSH_MAX_BACKLOG 32768
329 #define OUR_V2_WINSIZE 16384
330
331 const static struct ssh_kex *kex_algs[] = {
332 &ssh_diffiehellman_gex,
333 &ssh_diffiehellman
334 };
335
336 const static struct ssh_signkey *hostkey_algs[] = { &ssh_rsa, &ssh_dss };
337
338 static void *nullmac_make_context(void)
339 {
340 return NULL;
341 }
342 static void nullmac_free_context(void *handle)
343 {
344 }
345 static void nullmac_key(void *handle, unsigned char *key)
346 {
347 }
348 static void nullmac_generate(void *handle, unsigned char *blk, int len,
349 unsigned long seq)
350 {
351 }
352 static int nullmac_verify(void *handle, unsigned char *blk, int len,
353 unsigned long seq)
354 {
355 return 1;
356 }
357 const static struct ssh_mac ssh_mac_none = {
358 nullmac_make_context, nullmac_free_context, nullmac_key,
359 nullmac_generate, nullmac_verify, "none", 0
360 };
361 const static struct ssh_mac *macs[] = {
362 &ssh_sha1, &ssh_md5, &ssh_mac_none
363 };
364 const static struct ssh_mac *buggymacs[] = {
365 &ssh_sha1_buggy, &ssh_md5, &ssh_mac_none
366 };
367
368 static void *ssh_comp_none_init(void)
369 {
370 return NULL;
371 }
372 static void ssh_comp_none_cleanup(void *handle)
373 {
374 }
375 static int ssh_comp_none_block(void *handle, unsigned char *block, int len,
376 unsigned char **outblock, int *outlen)
377 {
378 return 0;
379 }
380 static int ssh_comp_none_disable(void *handle)
381 {
382 return 0;
383 }
384 const static struct ssh_compress ssh_comp_none = {
385 "none",
386 ssh_comp_none_init, ssh_comp_none_cleanup, ssh_comp_none_block,
387 ssh_comp_none_init, ssh_comp_none_cleanup, ssh_comp_none_block,
388 ssh_comp_none_disable, NULL
389 };
390 extern const struct ssh_compress ssh_zlib;
391 const static struct ssh_compress *compressions[] = {
392 &ssh_zlib, &ssh_comp_none
393 };
394
395 enum { /* channel types */
396 CHAN_MAINSESSION,
397 CHAN_X11,
398 CHAN_AGENT,
399 CHAN_SOCKDATA,
400 CHAN_SOCKDATA_DORMANT /* one the remote hasn't confirmed */
401 };
402
403 /*
404 * 2-3-4 tree storing channels.
405 */
406 struct ssh_channel {
407 Ssh ssh; /* pointer back to main context */
408 unsigned remoteid, localid;
409 int type;
410 /*
411 * In SSH1, this value contains four bits:
412 *
413 * 1 We have sent SSH1_MSG_CHANNEL_CLOSE.
414 * 2 We have sent SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION.
415 * 4 We have received SSH1_MSG_CHANNEL_CLOSE.
416 * 8 We have received SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION.
417 *
418 * A channel is completely finished with when all four bits are set.
419 */
420 int closes;
421 union {
422 struct ssh1_data_channel {
423 int throttling;
424 } v1;
425 struct ssh2_data_channel {
426 bufchain outbuffer;
427 unsigned remwindow, remmaxpkt;
428 unsigned locwindow;
429 } v2;
430 } v;
431 union {
432 struct ssh_agent_channel {
433 unsigned char *message;
434 unsigned char msglen[4];
435 int lensofar, totallen;
436 } a;
437 struct ssh_x11_channel {
438 Socket s;
439 } x11;
440 struct ssh_pfd_channel {
441 Socket s;
442 } pfd;
443 } u;
444 };
445
446 /*
447 * 2-3-4 tree storing remote->local port forwardings. SSH 1 and SSH
448 * 2 use this structure in different ways, reflecting SSH 2's
449 * altogether saner approach to port forwarding.
450 *
451 * In SSH 1, you arrange a remote forwarding by sending the server
452 * the remote port number, and the local destination host:port.
453 * When a connection comes in, the server sends you back that
454 * host:port pair, and you connect to it. This is a ready-made
455 * security hole if you're not on the ball: a malicious server
456 * could send you back _any_ host:port pair, so if you trustingly
457 * connect to the address it gives you then you've just opened the
458 * entire inside of your corporate network just by connecting
459 * through it to a dodgy SSH server. Hence, we must store a list of
460 * host:port pairs we _are_ trying to forward to, and reject a
461 * connection request from the server if it's not in the list.
462 *
463 * In SSH 2, each side of the connection minds its own business and
464 * doesn't send unnecessary information to the other. You arrange a
465 * remote forwarding by sending the server just the remote port
466 * number. When a connection comes in, the server tells you which
467 * of its ports was connected to; and _you_ have to remember what
468 * local host:port pair went with that port number.
469 *
470 * Hence: in SSH 1 this structure stores host:port pairs we intend
471 * to allow connections to, and is indexed by those host:port
472 * pairs. In SSH 2 it stores a mapping from source port to
473 * destination host:port pair, and is indexed by source port.
474 */
475 struct ssh_rportfwd {
476 unsigned sport, dport;
477 char dhost[256];
478 };
479
480 struct Packet {
481 long length;
482 int type;
483 unsigned char *data;
484 unsigned char *body;
485 long savedpos;
486 long maxlen;
487 };
488
489 static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt);
490 static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt);
491 static void ssh_size(void *handle, int width, int height);
492 static void ssh_special(void *handle, Telnet_Special);
493 static int ssh2_try_send(struct ssh_channel *c);
494 static void ssh2_add_channel_data(struct ssh_channel *c, char *buf, int len);
495 static void ssh_throttle_all(Ssh ssh, int enable, int bufsize);
496 static void ssh2_set_window(struct ssh_channel *c, unsigned newwin);
497 static int ssh_sendbuffer(void *handle);
498
499 struct rdpkt1_state_tag {
500 long len, pad, biglen, to_read;
501 unsigned long realcrc, gotcrc;
502 unsigned char *p;
503 int i;
504 int chunk;
505 };
506
507 struct rdpkt2_state_tag {
508 long len, pad, payload, packetlen, maclen;
509 int i;
510 int cipherblk;
511 unsigned long incoming_sequence;
512 };
513
514 struct ssh_tag {
515 const struct plug_function_table *fn;
516 /* the above field _must_ be first in the structure */
517
518 SHA_State exhash, exhashbase;
519
520 Socket s;
521
522 void *ldisc;
523 void *logctx;
524
525 unsigned char session_key[32];
526 int v1_compressing;
527 int v1_remote_protoflags;
528 int v1_local_protoflags;
529 int agentfwd_enabled;
530 int X11_fwd_enabled;
531 int remote_bugs;
532 const struct ssh_cipher *cipher;
533 void *v1_cipher_ctx;
534 void *crcda_ctx;
535 const struct ssh2_cipher *cscipher, *sccipher;
536 void *cs_cipher_ctx, *sc_cipher_ctx;
537 const struct ssh_mac *csmac, *scmac;
538 void *cs_mac_ctx, *sc_mac_ctx;
539 const struct ssh_compress *cscomp, *sccomp;
540 void *cs_comp_ctx, *sc_comp_ctx;
541 const struct ssh_kex *kex;
542 const struct ssh_signkey *hostkey;
543 unsigned char v2_session_id[20];
544 void *kex_ctx;
545
546 char *savedhost;
547 int savedport;
548 int send_ok;
549 int echoing, editing;
550
551 void *frontend;
552
553 int term_width, term_height;
554
555 tree234 *channels; /* indexed by local id */
556 struct ssh_channel *mainchan; /* primary session channel */
557 int exitcode;
558
559 tree234 *rportfwds;
560
561 enum {
562 SSH_STATE_PREPACKET,
563 SSH_STATE_BEFORE_SIZE,
564 SSH_STATE_INTERMED,
565 SSH_STATE_SESSION,
566 SSH_STATE_CLOSED
567 } state;
568
569 int size_needed, eof_needed;
570
571 struct Packet pktin;
572 struct Packet pktout;
573 unsigned char *deferred_send_data;
574 int deferred_len, deferred_size;
575
576 /*
577 * Gross hack: pscp will try to start SFTP but fall back to
578 * scp1 if that fails. This variable is the means by which
579 * scp.c can reach into the SSH code and find out which one it
580 * got.
581 */
582 int fallback_cmd;
583
584 /*
585 * Used for username and password input.
586 */
587 char *userpass_input_buffer;
588 int userpass_input_buflen;
589 int userpass_input_bufpos;
590 int userpass_input_echo;
591
592 char *portfwd_strptr;
593 int pkt_ctx;
594
595 void *x11auth;
596
597 int version;
598 int v1_throttle_count;
599 int overall_bufsize;
600 int throttled_all;
601 int v1_stdout_throttling;
602 int v2_outgoing_sequence;
603
604 int ssh1_rdpkt_crstate;
605 int ssh2_rdpkt_crstate;
606 int do_ssh_init_crstate;
607 int ssh_gotdata_crstate;
608 int ssh1_protocol_crstate;
609 int do_ssh1_login_crstate;
610 int do_ssh2_transport_crstate;
611 int do_ssh2_authconn_crstate;
612
613 void *do_ssh_init_state;
614 void *do_ssh1_login_state;
615 void *do_ssh2_transport_state;
616 void *do_ssh2_authconn_state;
617
618 struct rdpkt1_state_tag rdpkt1_state;
619 struct rdpkt2_state_tag rdpkt2_state;
620
621 void (*protocol) (Ssh ssh, unsigned char *in, int inlen, int ispkt);
622 int (*s_rdpkt) (Ssh ssh, unsigned char **data, int *datalen);
623
624 /*
625 * We maintain a full _copy_ of a Config structure here, not
626 * merely a pointer to it. That way, when we're passed a new
627 * one for reconfiguration, we can check the differences and
628 * potentially reconfigure port forwardings etc in mid-session.
629 */
630 Config cfg;
631 };
632
633 #define logevent(s) logevent(ssh->frontend, s)
634
635 /* logevent, only printf-formatted. */
636 static void logeventf(Ssh ssh, char *fmt, ...)
637 {
638 va_list ap;
639 char *buf;
640
641 va_start(ap, fmt);
642 buf = dupvprintf(fmt, ap);
643 va_end(ap);
644 logevent(buf);
645 sfree(buf);
646 }
647
648 #define bombout(msg) ( ssh->state = SSH_STATE_CLOSED, \
649 (ssh->s ? sk_close(ssh->s), ssh->s = NULL : 0), \
650 logeventf msg, connection_fatal msg )
651
652 static int ssh_channelcmp(void *av, void *bv)
653 {
654 struct ssh_channel *a = (struct ssh_channel *) av;
655 struct ssh_channel *b = (struct ssh_channel *) bv;
656 if (a->localid < b->localid)
657 return -1;
658 if (a->localid > b->localid)
659 return +1;
660 return 0;
661 }
662 static int ssh_channelfind(void *av, void *bv)
663 {
664 unsigned *a = (unsigned *) av;
665 struct ssh_channel *b = (struct ssh_channel *) bv;
666 if (*a < b->localid)
667 return -1;
668 if (*a > b->localid)
669 return +1;
670 return 0;
671 }
672
673 static int ssh_rportcmp_ssh1(void *av, void *bv)
674 {
675 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
676 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
677 int i;
678 if ( (i = strcmp(a->dhost, b->dhost)) != 0)
679 return i < 0 ? -1 : +1;
680 if (a->dport > b->dport)
681 return +1;
682 if (a->dport < b->dport)
683 return -1;
684 return 0;
685 }
686
687 static int ssh_rportcmp_ssh2(void *av, void *bv)
688 {
689 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
690 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
691
692 if (a->sport > b->sport)
693 return +1;
694 if (a->sport < b->sport)
695 return -1;
696 return 0;
697 }
698
699 static int alloc_channel_id(Ssh ssh)
700 {
701 const unsigned CHANNEL_NUMBER_OFFSET = 256;
702 unsigned low, high, mid;
703 int tsize;
704 struct ssh_channel *c;
705
706 /*
707 * First-fit allocation of channel numbers: always pick the
708 * lowest unused one. To do this, binary-search using the
709 * counted B-tree to find the largest channel ID which is in a
710 * contiguous sequence from the beginning. (Precisely
711 * everything in that sequence must have ID equal to its tree
712 * index plus CHANNEL_NUMBER_OFFSET.)
713 */
714 tsize = count234(ssh->channels);
715
716 low = -1;
717 high = tsize;
718 while (high - low > 1) {
719 mid = (high + low) / 2;
720 c = index234(ssh->channels, mid);
721 if (c->localid == mid + CHANNEL_NUMBER_OFFSET)
722 low = mid; /* this one is fine */
723 else
724 high = mid; /* this one is past it */
725 }
726 /*
727 * Now low points to either -1, or the tree index of the
728 * largest ID in the initial sequence.
729 */
730 {
731 unsigned i = low + 1 + CHANNEL_NUMBER_OFFSET;
732 assert(NULL == find234(ssh->channels, &i, ssh_channelfind));
733 }
734 return low + 1 + CHANNEL_NUMBER_OFFSET;
735 }
736
737 static void c_write(Ssh ssh, char *buf, int len)
738 {
739 if ((flags & FLAG_STDERR)) {
740 int i;
741 for (i = 0; i < len; i++)
742 if (buf[i] != '\r')
743 fputc(buf[i], stderr);
744 return;
745 }
746 from_backend(ssh->frontend, 1, buf, len);
747 }
748
749 static void c_write_untrusted(Ssh ssh, char *buf, int len)
750 {
751 int i;
752 for (i = 0; i < len; i++) {
753 if (buf[i] == '\n')
754 c_write(ssh, "\r\n", 2);
755 else if ((buf[i] & 0x60) || (buf[i] == '\r'))
756 c_write(ssh, buf + i, 1);
757 }
758 }
759
760 static void c_write_str(Ssh ssh, char *buf)
761 {
762 c_write(ssh, buf, strlen(buf));
763 }
764
765 /*
766 * Collect incoming data in the incoming packet buffer.
767 * Decipher and verify the packet when it is completely read.
768 * Drop SSH1_MSG_DEBUG and SSH1_MSG_IGNORE packets.
769 * Update the *data and *datalen variables.
770 * Return the additional nr of bytes needed, or 0 when
771 * a complete packet is available.
772 */
773 static int ssh1_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
774 {
775 struct rdpkt1_state_tag *st = &ssh->rdpkt1_state;
776
777 crBegin(ssh->ssh1_rdpkt_crstate);
778
779 next_packet:
780
781 ssh->pktin.type = 0;
782 ssh->pktin.length = 0;
783
784 for (st->i = st->len = 0; st->i < 4; st->i++) {
785 while ((*datalen) == 0)
786 crReturn(4 - st->i);
787 st->len = (st->len << 8) + **data;
788 (*data)++, (*datalen)--;
789 }
790
791 st->pad = 8 - (st->len % 8);
792 st->biglen = st->len + st->pad;
793 ssh->pktin.length = st->len - 5;
794
795 if (ssh->pktin.maxlen < st->biglen) {
796 ssh->pktin.maxlen = st->biglen;
797 ssh->pktin.data = srealloc(ssh->pktin.data, st->biglen + APIEXTRA);
798 }
799
800 st->to_read = st->biglen;
801 st->p = ssh->pktin.data;
802 while (st->to_read > 0) {
803 st->chunk = st->to_read;
804 while ((*datalen) == 0)
805 crReturn(st->to_read);
806 if (st->chunk > (*datalen))
807 st->chunk = (*datalen);
808 memcpy(st->p, *data, st->chunk);
809 *data += st->chunk;
810 *datalen -= st->chunk;
811 st->p += st->chunk;
812 st->to_read -= st->chunk;
813 }
814
815 if (ssh->cipher && detect_attack(ssh->crcda_ctx, ssh->pktin.data,
816 st->biglen, NULL)) {
817 bombout((ssh,"Network attack (CRC compensation) detected!"));
818 crReturn(0);
819 }
820
821 if (ssh->cipher)
822 ssh->cipher->decrypt(ssh->v1_cipher_ctx, ssh->pktin.data, st->biglen);
823
824 st->realcrc = crc32(ssh->pktin.data, st->biglen - 4);
825 st->gotcrc = GET_32BIT(ssh->pktin.data + st->biglen - 4);
826 if (st->gotcrc != st->realcrc) {
827 bombout((ssh,"Incorrect CRC received on packet"));
828 crReturn(0);
829 }
830
831 ssh->pktin.body = ssh->pktin.data + st->pad + 1;
832
833 if (ssh->v1_compressing) {
834 unsigned char *decompblk;
835 int decomplen;
836 zlib_decompress_block(ssh->sc_comp_ctx,
837 ssh->pktin.body - 1, ssh->pktin.length + 1,
838 &decompblk, &decomplen);
839
840 if (ssh->pktin.maxlen < st->pad + decomplen) {
841 ssh->pktin.maxlen = st->pad + decomplen;
842 ssh->pktin.data = srealloc(ssh->pktin.data,
843 ssh->pktin.maxlen + APIEXTRA);
844 ssh->pktin.body = ssh->pktin.data + st->pad + 1;
845 }
846
847 memcpy(ssh->pktin.body - 1, decompblk, decomplen);
848 sfree(decompblk);
849 ssh->pktin.length = decomplen - 1;
850 }
851
852 ssh->pktin.type = ssh->pktin.body[-1];
853
854 if (ssh->logctx)
855 log_packet(ssh->logctx,
856 PKT_INCOMING, ssh->pktin.type,
857 ssh1_pkt_type(ssh->pktin.type),
858 ssh->pktin.body, ssh->pktin.length);
859
860 if (ssh->pktin.type == SSH1_SMSG_STDOUT_DATA ||
861 ssh->pktin.type == SSH1_SMSG_STDERR_DATA ||
862 ssh->pktin.type == SSH1_MSG_DEBUG ||
863 ssh->pktin.type == SSH1_SMSG_AUTH_TIS_CHALLENGE ||
864 ssh->pktin.type == SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
865 long stringlen = GET_32BIT(ssh->pktin.body);
866 if (stringlen + 4 != ssh->pktin.length) {
867 bombout((ssh,"Received data packet with bogus string length"));
868 crReturn(0);
869 }
870 }
871
872 if (ssh->pktin.type == SSH1_MSG_DEBUG) {
873 /* log debug message */
874 char buf[512];
875 int stringlen = GET_32BIT(ssh->pktin.body);
876 strcpy(buf, "Remote debug message: ");
877 if (stringlen > 480)
878 stringlen = 480;
879 memcpy(buf + 8, ssh->pktin.body + 4, stringlen);
880 buf[8 + stringlen] = '\0';
881 logevent(buf);
882 goto next_packet;
883 } else if (ssh->pktin.type == SSH1_MSG_IGNORE) {
884 /* do nothing */
885 goto next_packet;
886 }
887
888 if (ssh->pktin.type == SSH1_MSG_DISCONNECT) {
889 /* log reason code in disconnect message */
890 char buf[256];
891 unsigned msglen = GET_32BIT(ssh->pktin.body);
892 unsigned nowlen;
893 strcpy(buf, "Remote sent disconnect: ");
894 nowlen = strlen(buf);
895 if (msglen > sizeof(buf) - nowlen - 1)
896 msglen = sizeof(buf) - nowlen - 1;
897 memcpy(buf + nowlen, ssh->pktin.body + 4, msglen);
898 buf[nowlen + msglen] = '\0';
899 /* logevent(buf); (this is now done within the bombout macro) */
900 bombout((ssh,"Server sent disconnect message:\n\"%s\"", buf+nowlen));
901 crReturn(0);
902 }
903
904 crFinish(0);
905 }
906
907 static int ssh2_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
908 {
909 struct rdpkt2_state_tag *st = &ssh->rdpkt2_state;
910
911 crBegin(ssh->ssh2_rdpkt_crstate);
912
913 next_packet:
914 ssh->pktin.type = 0;
915 ssh->pktin.length = 0;
916 if (ssh->sccipher)
917 st->cipherblk = ssh->sccipher->blksize;
918 else
919 st->cipherblk = 8;
920 if (st->cipherblk < 8)
921 st->cipherblk = 8;
922
923 if (ssh->pktin.maxlen < st->cipherblk) {
924 ssh->pktin.maxlen = st->cipherblk;
925 ssh->pktin.data = srealloc(ssh->pktin.data, st->cipherblk + APIEXTRA);
926 }
927
928 /*
929 * Acquire and decrypt the first block of the packet. This will
930 * contain the length and padding details.
931 */
932 for (st->i = st->len = 0; st->i < st->cipherblk; st->i++) {
933 while ((*datalen) == 0)
934 crReturn(st->cipherblk - st->i);
935 ssh->pktin.data[st->i] = *(*data)++;
936 (*datalen)--;
937 }
938
939 if (ssh->sccipher)
940 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
941 ssh->pktin.data, st->cipherblk);
942
943 /*
944 * Now get the length and padding figures.
945 */
946 st->len = GET_32BIT(ssh->pktin.data);
947 st->pad = ssh->pktin.data[4];
948
949 /*
950 * _Completely_ silly lengths should be stomped on before they
951 * do us any more damage.
952 */
953 if (st->len < 0 || st->pad < 0 || st->len + st->pad < 0) {
954 bombout((ssh,"Incoming packet was garbled on decryption"));
955 crReturn(0);
956 }
957
958 /*
959 * This enables us to deduce the payload length.
960 */
961 st->payload = st->len - st->pad - 1;
962
963 ssh->pktin.length = st->payload + 5;
964
965 /*
966 * So now we can work out the total packet length.
967 */
968 st->packetlen = st->len + 4;
969 st->maclen = ssh->scmac ? ssh->scmac->len : 0;
970
971 /*
972 * Adjust memory allocation if packet is too big.
973 */
974 if (ssh->pktin.maxlen < st->packetlen + st->maclen) {
975 ssh->pktin.maxlen = st->packetlen + st->maclen;
976 ssh->pktin.data = srealloc(ssh->pktin.data,
977 ssh->pktin.maxlen + APIEXTRA);
978 }
979
980 /*
981 * Read and decrypt the remainder of the packet.
982 */
983 for (st->i = st->cipherblk; st->i < st->packetlen + st->maclen;
984 st->i++) {
985 while ((*datalen) == 0)
986 crReturn(st->packetlen + st->maclen - st->i);
987 ssh->pktin.data[st->i] = *(*data)++;
988 (*datalen)--;
989 }
990 /* Decrypt everything _except_ the MAC. */
991 if (ssh->sccipher)
992 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
993 ssh->pktin.data + st->cipherblk,
994 st->packetlen - st->cipherblk);
995
996 /*
997 * Check the MAC.
998 */
999 if (ssh->scmac
1000 && !ssh->scmac->verify(ssh->sc_mac_ctx, ssh->pktin.data, st->len + 4,
1001 st->incoming_sequence)) {
1002 bombout((ssh,"Incorrect MAC received on packet"));
1003 crReturn(0);
1004 }
1005 st->incoming_sequence++; /* whether or not we MACed */
1006
1007 /*
1008 * Decompress packet payload.
1009 */
1010 {
1011 unsigned char *newpayload;
1012 int newlen;
1013 if (ssh->sccomp &&
1014 ssh->sccomp->decompress(ssh->sc_comp_ctx,
1015 ssh->pktin.data + 5, ssh->pktin.length - 5,
1016 &newpayload, &newlen)) {
1017 if (ssh->pktin.maxlen < newlen + 5) {
1018 ssh->pktin.maxlen = newlen + 5;
1019 ssh->pktin.data = srealloc(ssh->pktin.data,
1020 ssh->pktin.maxlen + APIEXTRA);
1021 }
1022 ssh->pktin.length = 5 + newlen;
1023 memcpy(ssh->pktin.data + 5, newpayload, newlen);
1024 sfree(newpayload);
1025 }
1026 }
1027
1028 ssh->pktin.savedpos = 6;
1029 ssh->pktin.type = ssh->pktin.data[5];
1030
1031 if (ssh->logctx)
1032 log_packet(ssh->logctx, PKT_INCOMING, ssh->pktin.type,
1033 ssh2_pkt_type(ssh->pkt_ctx, ssh->pktin.type),
1034 ssh->pktin.data+6, ssh->pktin.length-6);
1035
1036 switch (ssh->pktin.type) {
1037 /*
1038 * These packets we must handle instantly.
1039 */
1040 case SSH2_MSG_DISCONNECT:
1041 {
1042 /* log reason code in disconnect message */
1043 char *buf;
1044 int nowlen;
1045 int reason = GET_32BIT(ssh->pktin.data + 6);
1046 unsigned msglen = GET_32BIT(ssh->pktin.data + 10);
1047
1048 if (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) {
1049 buf = dupprintf("Received disconnect message (%s)",
1050 ssh2_disconnect_reasons[reason]);
1051 } else {
1052 buf = dupprintf("Received disconnect message (unknown"
1053 " type %d)", reason);
1054 }
1055 logevent(buf);
1056 sfree(buf);
1057 buf = dupprintf("Disconnection message text: %n%.*s",
1058 &nowlen, msglen, ssh->pktin.data + 14);
1059 logevent(buf);
1060 bombout((ssh,"Server sent disconnect message\ntype %d (%s):\n\"%s\"",
1061 reason,
1062 (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) ?
1063 ssh2_disconnect_reasons[reason] : "unknown",
1064 buf+nowlen));
1065 sfree(buf);
1066 crReturn(0);
1067 }
1068 break;
1069 case SSH2_MSG_IGNORE:
1070 goto next_packet;
1071 case SSH2_MSG_DEBUG:
1072 {
1073 /* log the debug message */
1074 char buf[512];
1075 /* int display = ssh->pktin.body[6]; */
1076 int stringlen = GET_32BIT(ssh->pktin.data+7);
1077 int prefix;
1078 strcpy(buf, "Remote debug message: ");
1079 prefix = strlen(buf);
1080 if (stringlen > (int)(sizeof(buf)-prefix-1))
1081 stringlen = sizeof(buf)-prefix-1;
1082 memcpy(buf + prefix, ssh->pktin.data + 11, stringlen);
1083 buf[prefix + stringlen] = '\0';
1084 logevent(buf);
1085 }
1086 goto next_packet; /* FIXME: print the debug message */
1087
1088 /*
1089 * These packets we need do nothing about here.
1090 */
1091 case SSH2_MSG_UNIMPLEMENTED:
1092 case SSH2_MSG_SERVICE_REQUEST:
1093 case SSH2_MSG_SERVICE_ACCEPT:
1094 case SSH2_MSG_KEXINIT:
1095 case SSH2_MSG_NEWKEYS:
1096 case SSH2_MSG_KEXDH_INIT:
1097 case SSH2_MSG_KEXDH_REPLY:
1098 /* case SSH2_MSG_KEX_DH_GEX_REQUEST: duplicate case value */
1099 /* case SSH2_MSG_KEX_DH_GEX_GROUP: duplicate case value */
1100 case SSH2_MSG_KEX_DH_GEX_INIT:
1101 case SSH2_MSG_KEX_DH_GEX_REPLY:
1102 case SSH2_MSG_USERAUTH_REQUEST:
1103 case SSH2_MSG_USERAUTH_FAILURE:
1104 case SSH2_MSG_USERAUTH_SUCCESS:
1105 case SSH2_MSG_USERAUTH_BANNER:
1106 case SSH2_MSG_USERAUTH_PK_OK:
1107 /* case SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ: duplicate case value */
1108 /* case SSH2_MSG_USERAUTH_INFO_REQUEST: duplicate case value */
1109 case SSH2_MSG_USERAUTH_INFO_RESPONSE:
1110 case SSH2_MSG_GLOBAL_REQUEST:
1111 case SSH2_MSG_REQUEST_SUCCESS:
1112 case SSH2_MSG_REQUEST_FAILURE:
1113 case SSH2_MSG_CHANNEL_OPEN:
1114 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION:
1115 case SSH2_MSG_CHANNEL_OPEN_FAILURE:
1116 case SSH2_MSG_CHANNEL_WINDOW_ADJUST:
1117 case SSH2_MSG_CHANNEL_DATA:
1118 case SSH2_MSG_CHANNEL_EXTENDED_DATA:
1119 case SSH2_MSG_CHANNEL_EOF:
1120 case SSH2_MSG_CHANNEL_CLOSE:
1121 case SSH2_MSG_CHANNEL_REQUEST:
1122 case SSH2_MSG_CHANNEL_SUCCESS:
1123 case SSH2_MSG_CHANNEL_FAILURE:
1124 break;
1125
1126 /*
1127 * For anything else we send SSH2_MSG_UNIMPLEMENTED.
1128 */
1129 default:
1130 ssh2_pkt_init(ssh, SSH2_MSG_UNIMPLEMENTED);
1131 ssh2_pkt_adduint32(ssh, st->incoming_sequence - 1);
1132 ssh2_pkt_send(ssh);
1133 break;
1134 }
1135
1136 crFinish(0);
1137 }
1138
1139 static void ssh1_pktout_size(Ssh ssh, int len)
1140 {
1141 int pad, biglen;
1142
1143 len += 5; /* type and CRC */
1144 pad = 8 - (len % 8);
1145 biglen = len + pad;
1146
1147 ssh->pktout.length = len - 5;
1148 if (ssh->pktout.maxlen < biglen) {
1149 ssh->pktout.maxlen = biglen;
1150 #ifdef MSCRYPTOAPI
1151 /* Allocate enough buffer space for extra block
1152 * for MS CryptEncrypt() */
1153 ssh->pktout.data = srealloc(ssh->pktout.data, biglen + 12);
1154 #else
1155 ssh->pktout.data = srealloc(ssh->pktout.data, biglen + 4);
1156 #endif
1157 }
1158 ssh->pktout.body = ssh->pktout.data + 4 + pad + 1;
1159 }
1160
1161 static void s_wrpkt_start(Ssh ssh, int type, int len)
1162 {
1163 ssh1_pktout_size(ssh, len);
1164 ssh->pktout.type = type;
1165 }
1166
1167 static int s_wrpkt_prepare(Ssh ssh)
1168 {
1169 int pad, len, biglen, i;
1170 unsigned long crc;
1171
1172 ssh->pktout.body[-1] = ssh->pktout.type;
1173
1174 if (ssh->logctx)
1175 log_packet(ssh->logctx, PKT_OUTGOING, ssh->pktout.type,
1176 ssh1_pkt_type(ssh->pktout.type),
1177 ssh->pktout.body, ssh->pktout.length);
1178
1179 if (ssh->v1_compressing) {
1180 unsigned char *compblk;
1181 int complen;
1182 zlib_compress_block(ssh->cs_comp_ctx,
1183 ssh->pktout.body - 1, ssh->pktout.length + 1,
1184 &compblk, &complen);
1185 ssh1_pktout_size(ssh, complen - 1);
1186 memcpy(ssh->pktout.body - 1, compblk, complen);
1187 sfree(compblk);
1188 }
1189
1190 len = ssh->pktout.length + 5; /* type and CRC */
1191 pad = 8 - (len % 8);
1192 biglen = len + pad;
1193
1194 for (i = 0; i < pad; i++)
1195 ssh->pktout.data[i + 4] = random_byte();
1196 crc = crc32(ssh->pktout.data + 4, biglen - 4);
1197 PUT_32BIT(ssh->pktout.data + biglen, crc);
1198 PUT_32BIT(ssh->pktout.data, len);
1199
1200 if (ssh->cipher)
1201 ssh->cipher->encrypt(ssh->v1_cipher_ctx, ssh->pktout.data + 4, biglen);
1202
1203 return biglen + 4;
1204 }
1205
1206 static void s_wrpkt(Ssh ssh)
1207 {
1208 int len, backlog;
1209 len = s_wrpkt_prepare(ssh);
1210 backlog = sk_write(ssh->s, (char *)ssh->pktout.data, len);
1211 if (backlog > SSH_MAX_BACKLOG)
1212 ssh_throttle_all(ssh, 1, backlog);
1213 }
1214
1215 static void s_wrpkt_defer(Ssh ssh)
1216 {
1217 int len;
1218 len = s_wrpkt_prepare(ssh);
1219 if (ssh->deferred_len + len > ssh->deferred_size) {
1220 ssh->deferred_size = ssh->deferred_len + len + 128;
1221 ssh->deferred_send_data = srealloc(ssh->deferred_send_data,
1222 ssh->deferred_size);
1223 }
1224 memcpy(ssh->deferred_send_data + ssh->deferred_len, ssh->pktout.data, len);
1225 ssh->deferred_len += len;
1226 }
1227
1228 /*
1229 * Construct a packet with the specified contents.
1230 */
1231 static void construct_packet(Ssh ssh, int pkttype, va_list ap1, va_list ap2)
1232 {
1233 unsigned char *p, *argp, argchar;
1234 unsigned long argint;
1235 int pktlen, argtype, arglen;
1236 Bignum bn;
1237
1238 pktlen = 0;
1239 while ((argtype = va_arg(ap1, int)) != PKT_END) {
1240 switch (argtype) {
1241 case PKT_INT:
1242 (void) va_arg(ap1, int);
1243 pktlen += 4;
1244 break;
1245 case PKT_CHAR:
1246 (void) va_arg(ap1, int);
1247 pktlen++;
1248 break;
1249 case PKT_DATA:
1250 (void) va_arg(ap1, unsigned char *);
1251 arglen = va_arg(ap1, int);
1252 pktlen += arglen;
1253 break;
1254 case PKT_STR:
1255 argp = va_arg(ap1, unsigned char *);
1256 arglen = strlen((char *)argp);
1257 pktlen += 4 + arglen;
1258 break;
1259 case PKT_BIGNUM:
1260 bn = va_arg(ap1, Bignum);
1261 pktlen += ssh1_bignum_length(bn);
1262 break;
1263 default:
1264 assert(0);
1265 }
1266 }
1267
1268 s_wrpkt_start(ssh, pkttype, pktlen);
1269 p = ssh->pktout.body;
1270
1271 while ((argtype = va_arg(ap2, int)) != PKT_END) {
1272 switch (argtype) {
1273 case PKT_INT:
1274 argint = va_arg(ap2, int);
1275 PUT_32BIT(p, argint);
1276 p += 4;
1277 break;
1278 case PKT_CHAR:
1279 argchar = (unsigned char) va_arg(ap2, int);
1280 *p = argchar;
1281 p++;
1282 break;
1283 case PKT_DATA:
1284 argp = va_arg(ap2, unsigned char *);
1285 arglen = va_arg(ap2, int);
1286 memcpy(p, argp, arglen);
1287 p += arglen;
1288 break;
1289 case PKT_STR:
1290 argp = va_arg(ap2, unsigned char *);
1291 arglen = strlen((char *)argp);
1292 PUT_32BIT(p, arglen);
1293 memcpy(p + 4, argp, arglen);
1294 p += 4 + arglen;
1295 break;
1296 case PKT_BIGNUM:
1297 bn = va_arg(ap2, Bignum);
1298 p += ssh1_write_bignum(p, bn);
1299 break;
1300 }
1301 }
1302 }
1303
1304 static void send_packet(Ssh ssh, int pkttype, ...)
1305 {
1306 va_list ap1, ap2;
1307 va_start(ap1, pkttype);
1308 va_start(ap2, pkttype);
1309 construct_packet(ssh, pkttype, ap1, ap2);
1310 s_wrpkt(ssh);
1311 }
1312
1313 static void defer_packet(Ssh ssh, int pkttype, ...)
1314 {
1315 va_list ap1, ap2;
1316 va_start(ap1, pkttype);
1317 va_start(ap2, pkttype);
1318 construct_packet(ssh, pkttype, ap1, ap2);
1319 s_wrpkt_defer(ssh);
1320 }
1321
1322 static int ssh_versioncmp(char *a, char *b)
1323 {
1324 char *ae, *be;
1325 unsigned long av, bv;
1326
1327 av = strtoul(a, &ae, 10);
1328 bv = strtoul(b, &be, 10);
1329 if (av != bv)
1330 return (av < bv ? -1 : +1);
1331 if (*ae == '.')
1332 ae++;
1333 if (*be == '.')
1334 be++;
1335 av = strtoul(ae, &ae, 10);
1336 bv = strtoul(be, &be, 10);
1337 if (av != bv)
1338 return (av < bv ? -1 : +1);
1339 return 0;
1340 }
1341
1342 /*
1343 * Utility routines for putting an SSH-protocol `string' and
1344 * `uint32' into a SHA state.
1345 */
1346 #include <stdio.h>
1347 static void sha_string(SHA_State * s, void *str, int len)
1348 {
1349 unsigned char lenblk[4];
1350 PUT_32BIT(lenblk, len);
1351 SHA_Bytes(s, lenblk, 4);
1352 SHA_Bytes(s, str, len);
1353 }
1354
1355 static void sha_uint32(SHA_State * s, unsigned i)
1356 {
1357 unsigned char intblk[4];
1358 PUT_32BIT(intblk, i);
1359 SHA_Bytes(s, intblk, 4);
1360 }
1361
1362 /*
1363 * SSH2 packet construction functions.
1364 */
1365 static void ssh2_pkt_ensure(Ssh ssh, int length)
1366 {
1367 if (ssh->pktout.maxlen < length) {
1368 ssh->pktout.maxlen = length + 256;
1369 ssh->pktout.data = srealloc(ssh->pktout.data,
1370 ssh->pktout.maxlen + APIEXTRA);
1371 if (!ssh->pktout.data)
1372 fatalbox("Out of memory");
1373 }
1374 }
1375 static void ssh2_pkt_adddata(Ssh ssh, void *data, int len)
1376 {
1377 ssh->pktout.length += len;
1378 ssh2_pkt_ensure(ssh, ssh->pktout.length);
1379 memcpy(ssh->pktout.data + ssh->pktout.length - len, data, len);
1380 }
1381 static void ssh2_pkt_addbyte(Ssh ssh, unsigned char byte)
1382 {
1383 ssh2_pkt_adddata(ssh, &byte, 1);
1384 }
1385 static void ssh2_pkt_init(Ssh ssh, int pkt_type)
1386 {
1387 ssh->pktout.length = 5;
1388 ssh2_pkt_addbyte(ssh, (unsigned char) pkt_type);
1389 }
1390 static void ssh2_pkt_addbool(Ssh ssh, unsigned char value)
1391 {
1392 ssh2_pkt_adddata(ssh, &value, 1);
1393 }
1394 static void ssh2_pkt_adduint32(Ssh ssh, unsigned long value)
1395 {
1396 unsigned char x[4];
1397 PUT_32BIT(x, value);
1398 ssh2_pkt_adddata(ssh, x, 4);
1399 }
1400 static void ssh2_pkt_addstring_start(Ssh ssh)
1401 {
1402 ssh2_pkt_adduint32(ssh, 0);
1403 ssh->pktout.savedpos = ssh->pktout.length;
1404 }
1405 static void ssh2_pkt_addstring_str(Ssh ssh, char *data)
1406 {
1407 ssh2_pkt_adddata(ssh, data, strlen(data));
1408 PUT_32BIT(ssh->pktout.data + ssh->pktout.savedpos - 4,
1409 ssh->pktout.length - ssh->pktout.savedpos);
1410 }
1411 static void ssh2_pkt_addstring_data(Ssh ssh, char *data, int len)
1412 {
1413 ssh2_pkt_adddata(ssh, data, len);
1414 PUT_32BIT(ssh->pktout.data + ssh->pktout.savedpos - 4,
1415 ssh->pktout.length - ssh->pktout.savedpos);
1416 }
1417 static void ssh2_pkt_addstring(Ssh ssh, char *data)
1418 {
1419 ssh2_pkt_addstring_start(ssh);
1420 ssh2_pkt_addstring_str(ssh, data);
1421 }
1422 static unsigned char *ssh2_mpint_fmt(Bignum b, int *len)
1423 {
1424 unsigned char *p;
1425 int i, n = (bignum_bitcount(b) + 7) / 8;
1426 p = smalloc(n + 1);
1427 if (!p)
1428 fatalbox("out of memory");
1429 p[0] = 0;
1430 for (i = 1; i <= n; i++)
1431 p[i] = bignum_byte(b, n - i);
1432 i = 0;
1433 while (i <= n && p[i] == 0 && (p[i + 1] & 0x80) == 0)
1434 i++;
1435 memmove(p, p + i, n + 1 - i);
1436 *len = n + 1 - i;
1437 return p;
1438 }
1439 static void ssh2_pkt_addmp(Ssh ssh, Bignum b)
1440 {
1441 unsigned char *p;
1442 int len;
1443 p = ssh2_mpint_fmt(b, &len);
1444 ssh2_pkt_addstring_start(ssh);
1445 ssh2_pkt_addstring_data(ssh, (char *)p, len);
1446 sfree(p);
1447 }
1448
1449 /*
1450 * Construct an SSH2 final-form packet: compress it, encrypt it,
1451 * put the MAC on it. Final packet, ready to be sent, is stored in
1452 * ssh->pktout.data. Total length is returned.
1453 */
1454 static int ssh2_pkt_construct(Ssh ssh)
1455 {
1456 int cipherblk, maclen, padding, i;
1457
1458 if (ssh->logctx)
1459 log_packet(ssh->logctx, PKT_OUTGOING, ssh->pktout.data[5],
1460 ssh2_pkt_type(ssh->pkt_ctx, ssh->pktout.data[5]),
1461 ssh->pktout.data + 6, ssh->pktout.length - 6);
1462
1463 /*
1464 * Compress packet payload.
1465 */
1466 {
1467 unsigned char *newpayload;
1468 int newlen;
1469 if (ssh->cscomp &&
1470 ssh->cscomp->compress(ssh->cs_comp_ctx, ssh->pktout.data + 5,
1471 ssh->pktout.length - 5,
1472 &newpayload, &newlen)) {
1473 ssh->pktout.length = 5;
1474 ssh2_pkt_adddata(ssh, newpayload, newlen);
1475 sfree(newpayload);
1476 }
1477 }
1478
1479 /*
1480 * Add padding. At least four bytes, and must also bring total
1481 * length (minus MAC) up to a multiple of the block size.
1482 */
1483 cipherblk = ssh->cscipher ? ssh->cscipher->blksize : 8; /* block size */
1484 cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */
1485 padding = 4;
1486 padding +=
1487 (cipherblk - (ssh->pktout.length + padding) % cipherblk) % cipherblk;
1488 maclen = ssh->csmac ? ssh->csmac->len : 0;
1489 ssh2_pkt_ensure(ssh, ssh->pktout.length + padding + maclen);
1490 ssh->pktout.data[4] = padding;
1491 for (i = 0; i < padding; i++)
1492 ssh->pktout.data[ssh->pktout.length + i] = random_byte();
1493 PUT_32BIT(ssh->pktout.data, ssh->pktout.length + padding - 4);
1494 if (ssh->csmac)
1495 ssh->csmac->generate(ssh->cs_mac_ctx, ssh->pktout.data,
1496 ssh->pktout.length + padding,
1497 ssh->v2_outgoing_sequence);
1498 ssh->v2_outgoing_sequence++; /* whether or not we MACed */
1499
1500 if (ssh->cscipher)
1501 ssh->cscipher->encrypt(ssh->cs_cipher_ctx,
1502 ssh->pktout.data, ssh->pktout.length + padding);
1503
1504 /* Ready-to-send packet starts at ssh->pktout.data. We return length. */
1505 return ssh->pktout.length + padding + maclen;
1506 }
1507
1508 /*
1509 * Construct and send an SSH2 packet immediately.
1510 */
1511 static void ssh2_pkt_send(Ssh ssh)
1512 {
1513 int len;
1514 int backlog;
1515 len = ssh2_pkt_construct(ssh);
1516 backlog = sk_write(ssh->s, (char *)ssh->pktout.data, len);
1517 if (backlog > SSH_MAX_BACKLOG)
1518 ssh_throttle_all(ssh, 1, backlog);
1519 }
1520
1521 /*
1522 * Construct an SSH2 packet and add it to a deferred data block.
1523 * Useful for sending multiple packets in a single sk_write() call,
1524 * to prevent a traffic-analysing listener from being able to work
1525 * out the length of any particular packet (such as the password
1526 * packet).
1527 *
1528 * Note that because SSH2 sequence-numbers its packets, this can
1529 * NOT be used as an m4-style `defer' allowing packets to be
1530 * constructed in one order and sent in another.
1531 */
1532 static void ssh2_pkt_defer(Ssh ssh)
1533 {
1534 int len = ssh2_pkt_construct(ssh);
1535 if (ssh->deferred_len + len > ssh->deferred_size) {
1536 ssh->deferred_size = ssh->deferred_len + len + 128;
1537 ssh->deferred_send_data = srealloc(ssh->deferred_send_data,
1538 ssh->deferred_size);
1539 }
1540 memcpy(ssh->deferred_send_data + ssh->deferred_len, ssh->pktout.data, len);
1541 ssh->deferred_len += len;
1542 }
1543
1544 /*
1545 * Send the whole deferred data block constructed by
1546 * ssh2_pkt_defer() or SSH1's defer_packet().
1547 */
1548 static void ssh_pkt_defersend(Ssh ssh)
1549 {
1550 int backlog;
1551 backlog = sk_write(ssh->s, (char *)ssh->deferred_send_data,
1552 ssh->deferred_len);
1553 ssh->deferred_len = ssh->deferred_size = 0;
1554 sfree(ssh->deferred_send_data);
1555 ssh->deferred_send_data = NULL;
1556 if (backlog > SSH_MAX_BACKLOG)
1557 ssh_throttle_all(ssh, 1, backlog);
1558 }
1559
1560 #if 0
1561 void bndebug(char *string, Bignum b)
1562 {
1563 unsigned char *p;
1564 int i, len;
1565 p = ssh2_mpint_fmt(b, &len);
1566 debug(("%s", string));
1567 for (i = 0; i < len; i++)
1568 debug((" %02x", p[i]));
1569 debug(("\n"));
1570 sfree(p);
1571 }
1572 #endif
1573
1574 static void sha_mpint(SHA_State * s, Bignum b)
1575 {
1576 unsigned char *p;
1577 int len;
1578 p = ssh2_mpint_fmt(b, &len);
1579 sha_string(s, p, len);
1580 sfree(p);
1581 }
1582
1583 /*
1584 * SSH2 packet decode functions.
1585 */
1586 static unsigned long ssh2_pkt_getuint32(Ssh ssh)
1587 {
1588 unsigned long value;
1589 if (ssh->pktin.length - ssh->pktin.savedpos < 4)
1590 return 0; /* arrgh, no way to decline (FIXME?) */
1591 value = GET_32BIT(ssh->pktin.data + ssh->pktin.savedpos);
1592 ssh->pktin.savedpos += 4;
1593 return value;
1594 }
1595 static int ssh2_pkt_getbool(Ssh ssh)
1596 {
1597 unsigned long value;
1598 if (ssh->pktin.length - ssh->pktin.savedpos < 1)
1599 return 0; /* arrgh, no way to decline (FIXME?) */
1600 value = ssh->pktin.data[ssh->pktin.savedpos] != 0;
1601 ssh->pktin.savedpos++;
1602 return value;
1603 }
1604 static void ssh2_pkt_getstring(Ssh ssh, char **p, int *length)
1605 {
1606 int len;
1607 *p = NULL;
1608 *length = 0;
1609 if (ssh->pktin.length - ssh->pktin.savedpos < 4)
1610 return;
1611 len = GET_32BIT(ssh->pktin.data + ssh->pktin.savedpos);
1612 if (len < 0)
1613 return;
1614 *length = len;
1615 ssh->pktin.savedpos += 4;
1616 if (ssh->pktin.length - ssh->pktin.savedpos < *length)
1617 return;
1618 *p = (char *)(ssh->pktin.data + ssh->pktin.savedpos);
1619 ssh->pktin.savedpos += *length;
1620 }
1621 static Bignum ssh2_pkt_getmp(Ssh ssh)
1622 {
1623 char *p;
1624 int length;
1625 Bignum b;
1626
1627 ssh2_pkt_getstring(ssh, &p, &length);
1628 if (!p)
1629 return NULL;
1630 if (p[0] & 0x80) {
1631 bombout((ssh,"internal error: Can't handle negative mpints"));
1632 return NULL;
1633 }
1634 b = bignum_from_bytes((unsigned char *)p, length);
1635 return b;
1636 }
1637
1638 /*
1639 * Helper function to add an SSH2 signature blob to a packet.
1640 * Expects to be shown the public key blob as well as the signature
1641 * blob. Normally works just like ssh2_pkt_addstring, but will
1642 * fiddle with the signature packet if necessary for
1643 * BUG_SSH2_RSA_PADDING.
1644 */
1645 static void ssh2_add_sigblob(Ssh ssh, void *pkblob_v, int pkblob_len,
1646 void *sigblob_v, int sigblob_len)
1647 {
1648 unsigned char *pkblob = (unsigned char *)pkblob_v;
1649 unsigned char *sigblob = (unsigned char *)sigblob_v;
1650
1651 /* dmemdump(pkblob, pkblob_len); */
1652 /* dmemdump(sigblob, sigblob_len); */
1653
1654 /*
1655 * See if this is in fact an ssh-rsa signature and a buggy
1656 * server; otherwise we can just do this the easy way.
1657 */
1658 if ((ssh->remote_bugs & BUG_SSH2_RSA_PADDING) &&
1659 (GET_32BIT(pkblob) == 7 && !memcmp(pkblob+4, "ssh-rsa", 7))) {
1660 int pos, len, siglen;
1661
1662 /*
1663 * Find the byte length of the modulus.
1664 */
1665
1666 pos = 4+7; /* skip over "ssh-rsa" */
1667 pos += 4 + GET_32BIT(pkblob+pos); /* skip over exponent */
1668 len = GET_32BIT(pkblob+pos); /* find length of modulus */
1669 pos += 4; /* find modulus itself */
1670 while (len > 0 && pkblob[pos] == 0)
1671 len--, pos++;
1672 /* debug(("modulus length is %d\n", len)); */
1673
1674 /*
1675 * Now find the signature integer.
1676 */
1677 pos = 4+7; /* skip over "ssh-rsa" */
1678 siglen = GET_32BIT(sigblob+pos);
1679 /* debug(("signature length is %d\n", siglen)); */
1680
1681 if (len != siglen) {
1682 unsigned char newlen[4];
1683 ssh2_pkt_addstring_start(ssh);
1684 ssh2_pkt_addstring_data(ssh, (char *)sigblob, pos);
1685 /* dmemdump(sigblob, pos); */
1686 pos += 4; /* point to start of actual sig */
1687 PUT_32BIT(newlen, len);
1688 ssh2_pkt_addstring_data(ssh, (char *)newlen, 4);
1689 /* dmemdump(newlen, 4); */
1690 newlen[0] = 0;
1691 while (len-- > siglen) {
1692 ssh2_pkt_addstring_data(ssh, (char *)newlen, 1);
1693 /* dmemdump(newlen, 1); */
1694 }
1695 ssh2_pkt_addstring_data(ssh, (char *)(sigblob+pos), siglen);
1696 /* dmemdump(sigblob+pos, siglen); */
1697 return;
1698 }
1699
1700 /* Otherwise fall through and do it the easy way. */
1701 }
1702
1703 ssh2_pkt_addstring_start(ssh);
1704 ssh2_pkt_addstring_data(ssh, (char *)sigblob, sigblob_len);
1705 }
1706
1707 /*
1708 * Examine the remote side's version string and compare it against
1709 * a list of known buggy implementations.
1710 */
1711 static void ssh_detect_bugs(Ssh ssh, char *vstring)
1712 {
1713 char *imp; /* pointer to implementation part */
1714 imp = vstring;
1715 imp += strcspn(imp, "-");
1716 if (*imp) imp++;
1717 imp += strcspn(imp, "-");
1718 if (*imp) imp++;
1719
1720 ssh->remote_bugs = 0;
1721
1722 if (ssh->cfg.sshbug_ignore1 == BUG_ON ||
1723 (ssh->cfg.sshbug_ignore1 == BUG_AUTO &&
1724 (!strcmp(imp, "1.2.18") || !strcmp(imp, "1.2.19") ||
1725 !strcmp(imp, "1.2.20") || !strcmp(imp, "1.2.21") ||
1726 !strcmp(imp, "1.2.22") || !strcmp(imp, "Cisco-1.25")))) {
1727 /*
1728 * These versions don't support SSH1_MSG_IGNORE, so we have
1729 * to use a different defence against password length
1730 * sniffing.
1731 */
1732 ssh->remote_bugs |= BUG_CHOKES_ON_SSH1_IGNORE;
1733 logevent("We believe remote version has SSH1 ignore bug");
1734 }
1735
1736 if (ssh->cfg.sshbug_plainpw1 == BUG_ON ||
1737 (ssh->cfg.sshbug_plainpw1 == BUG_AUTO &&
1738 (!strcmp(imp, "Cisco-1.25")))) {
1739 /*
1740 * These versions need a plain password sent; they can't
1741 * handle having a null and a random length of data after
1742 * the password.
1743 */
1744 ssh->remote_bugs |= BUG_NEEDS_SSH1_PLAIN_PASSWORD;
1745 logevent("We believe remote version needs a plain SSH1 password");
1746 }
1747
1748 if (ssh->cfg.sshbug_rsa1 == BUG_ON ||
1749 (ssh->cfg.sshbug_rsa1 == BUG_AUTO &&
1750 (!strcmp(imp, "Cisco-1.25")))) {
1751 /*
1752 * These versions apparently have no clue whatever about
1753 * RSA authentication and will panic and die if they see
1754 * an AUTH_RSA message.
1755 */
1756 ssh->remote_bugs |= BUG_CHOKES_ON_RSA;
1757 logevent("We believe remote version can't handle RSA authentication");
1758 }
1759
1760 if (ssh->cfg.sshbug_hmac2 == BUG_ON ||
1761 (ssh->cfg.sshbug_hmac2 == BUG_AUTO &&
1762 (wc_match("2.1.0*", imp) || wc_match("2.0.*", imp) ||
1763 wc_match("2.2.0*", imp) || wc_match("2.3.0*", imp) ||
1764 wc_match("2.1 *", imp)))) {
1765 /*
1766 * These versions have the HMAC bug.
1767 */
1768 ssh->remote_bugs |= BUG_SSH2_HMAC;
1769 logevent("We believe remote version has SSH2 HMAC bug");
1770 }
1771
1772 if (ssh->cfg.sshbug_derivekey2 == BUG_ON ||
1773 (ssh->cfg.sshbug_derivekey2 == BUG_AUTO &&
1774 (wc_match("2.0.0*", imp) || wc_match("2.0.1[01]*", imp) ))) {
1775 /*
1776 * These versions have the key-derivation bug (failing to
1777 * include the literal shared secret in the hashes that
1778 * generate the keys).
1779 */
1780 ssh->remote_bugs |= BUG_SSH2_DERIVEKEY;
1781 logevent("We believe remote version has SSH2 key-derivation bug");
1782 }
1783
1784 if (ssh->cfg.sshbug_rsapad2 == BUG_ON ||
1785 (ssh->cfg.sshbug_rsapad2 == BUG_AUTO &&
1786 (wc_match("OpenSSH_2.[5-9]*", imp) ||
1787 wc_match("OpenSSH_3.[0-2]*", imp)))) {
1788 /*
1789 * These versions have the SSH2 RSA padding bug.
1790 */
1791 ssh->remote_bugs |= BUG_SSH2_RSA_PADDING;
1792 logevent("We believe remote version has SSH2 RSA padding bug");
1793 }
1794
1795 if (ssh->cfg.sshbug_dhgex2 == BUG_ON) {
1796 /*
1797 * User specified the SSH2 DH GEX bug.
1798 */
1799 ssh->remote_bugs |= BUG_SSH2_DH_GEX;
1800 logevent("We believe remote version has SSH2 DH group exchange bug");
1801 }
1802 }
1803
1804 static int do_ssh_init(Ssh ssh, unsigned char c)
1805 {
1806 struct do_ssh_init_state {
1807 int vslen;
1808 char version[10];
1809 char *vstring;
1810 int vstrsize;
1811 int i;
1812 int proto1, proto2;
1813 };
1814 crState(do_ssh_init_state);
1815
1816 crBegin(ssh->do_ssh_init_crstate);
1817
1818 /* Search for the string "SSH-" in the input. */
1819 s->i = 0;
1820 while (1) {
1821 static const int transS[] = { 1, 2, 2, 1 };
1822 static const int transH[] = { 0, 0, 3, 0 };
1823 static const int transminus[] = { 0, 0, 0, -1 };
1824 if (c == 'S')
1825 s->i = transS[s->i];
1826 else if (c == 'H')
1827 s->i = transH[s->i];
1828 else if (c == '-')
1829 s->i = transminus[s->i];
1830 else
1831 s->i = 0;
1832 if (s->i < 0)
1833 break;
1834 crReturn(1); /* get another character */
1835 }
1836
1837 s->vstrsize = 16;
1838 s->vstring = smalloc(s->vstrsize);
1839 strcpy(s->vstring, "SSH-");
1840 s->vslen = 4;
1841 s->i = 0;
1842 while (1) {
1843 crReturn(1); /* get another char */
1844 if (s->vslen >= s->vstrsize - 1) {
1845 s->vstrsize += 16;
1846 s->vstring = srealloc(s->vstring, s->vstrsize);
1847 }
1848 s->vstring[s->vslen++] = c;
1849 if (s->i >= 0) {
1850 if (c == '-') {
1851 s->version[s->i] = '\0';
1852 s->i = -1;
1853 } else if (s->i < sizeof(s->version) - 1)
1854 s->version[s->i++] = c;
1855 } else if (c == '\012')
1856 break;
1857 }
1858
1859 ssh->agentfwd_enabled = FALSE;
1860 ssh->rdpkt2_state.incoming_sequence = 0;
1861
1862 s->vstring[s->vslen] = 0;
1863 s->vstring[strcspn(s->vstring, "\r\n")] = '\0';/* remove EOL chars */
1864 {
1865 char *vlog;
1866 vlog = smalloc(20 + s->vslen);
1867 sprintf(vlog, "Server version: %s", s->vstring);
1868 logevent(vlog);
1869 sfree(vlog);
1870 }
1871 ssh_detect_bugs(ssh, s->vstring);
1872
1873 /*
1874 * Decide which SSH protocol version to support.
1875 */
1876
1877 /* Anything strictly below "2.0" means protocol 1 is supported. */
1878 s->proto1 = ssh_versioncmp(s->version, "2.0") < 0;
1879 /* Anything greater or equal to "1.99" means protocol 2 is supported. */
1880 s->proto2 = ssh_versioncmp(s->version, "1.99") >= 0;
1881
1882 if (ssh->cfg.sshprot == 0 && !s->proto1) {
1883 bombout((ssh,"SSH protocol version 1 required by user but not provided by server"));
1884 crReturn(0);
1885 }
1886 if (ssh->cfg.sshprot == 3 && !s->proto2) {
1887 bombout((ssh,"SSH protocol version 2 required by user but not provided by server"));
1888 crReturn(0);
1889 }
1890
1891 if (s->proto2 && (ssh->cfg.sshprot >= 2 || !s->proto1)) {
1892 /*
1893 * Use v2 protocol.
1894 */
1895 char verstring[80], vlog[100];
1896 sprintf(verstring, "SSH-2.0-%s", sshver);
1897 SHA_Init(&ssh->exhashbase);
1898 /*
1899 * Hash our version string and their version string.
1900 */
1901 sha_string(&ssh->exhashbase, verstring, strlen(verstring));
1902 sha_string(&ssh->exhashbase, s->vstring, strcspn(s->vstring, "\r\n"));
1903 sprintf(vlog, "We claim version: %s", verstring);
1904 logevent(vlog);
1905 strcat(verstring, "\012");
1906 logevent("Using SSH protocol version 2");
1907 sk_write(ssh->s, verstring, strlen(verstring));
1908 ssh->protocol = ssh2_protocol;
1909 ssh->version = 2;
1910 ssh->s_rdpkt = ssh2_rdpkt;
1911 } else {
1912 /*
1913 * Use v1 protocol.
1914 */
1915 char verstring[80], vlog[100];
1916 sprintf(verstring, "SSH-%s-%s",
1917 (ssh_versioncmp(s->version, "1.5") <= 0 ? s->version : "1.5"),
1918 sshver);
1919 sprintf(vlog, "We claim version: %s", verstring);
1920 logevent(vlog);
1921 strcat(verstring, "\012");
1922
1923 logevent("Using SSH protocol version 1");
1924 sk_write(ssh->s, verstring, strlen(verstring));
1925 ssh->protocol = ssh1_protocol;
1926 ssh->version = 1;
1927 ssh->s_rdpkt = ssh1_rdpkt;
1928 }
1929 ssh->state = SSH_STATE_BEFORE_SIZE;
1930
1931 sfree(s->vstring);
1932
1933 crFinish(0);
1934 }
1935
1936 static void ssh_gotdata(Ssh ssh, unsigned char *data, int datalen)
1937 {
1938 crBegin(ssh->ssh_gotdata_crstate);
1939
1940 /*
1941 * To begin with, feed the characters one by one to the
1942 * protocol initialisation / selection function do_ssh_init().
1943 * When that returns 0, we're done with the initial greeting
1944 * exchange and can move on to packet discipline.
1945 */
1946 while (1) {
1947 int ret; /* need not be kept across crReturn */
1948 if (datalen == 0)
1949 crReturnV; /* more data please */
1950 ret = do_ssh_init(ssh, *data);
1951 data++;
1952 datalen--;
1953 if (ret == 0)
1954 break;
1955 }
1956
1957 /*
1958 * We emerge from that loop when the initial negotiation is
1959 * over and we have selected an s_rdpkt function. Now pass
1960 * everything to s_rdpkt, and then pass the resulting packets
1961 * to the proper protocol handler.
1962 */
1963 if (datalen == 0)
1964 crReturnV;
1965 while (1) {
1966 while (datalen > 0) {
1967 if (ssh->s_rdpkt(ssh, &data, &datalen) == 0) {
1968 if (ssh->state == SSH_STATE_CLOSED) {
1969 return;
1970 }
1971 ssh->protocol(ssh, NULL, 0, 1);
1972 if (ssh->state == SSH_STATE_CLOSED) {
1973 return;
1974 }
1975 }
1976 }
1977 crReturnV;
1978 }
1979 crFinishV;
1980 }
1981
1982 static int ssh_closing(Plug plug, char *error_msg, int error_code,
1983 int calling_back)
1984 {
1985 Ssh ssh = (Ssh) plug;
1986 ssh->state = SSH_STATE_CLOSED;
1987 if (ssh->s) {
1988 sk_close(ssh->s);
1989 ssh->s = NULL;
1990 }
1991 if (error_msg) {
1992 /* A socket error has occurred. */
1993 logevent(error_msg);
1994 connection_fatal(ssh->frontend, error_msg);
1995 } else {
1996 /* Otherwise, the remote side closed the connection normally. */
1997 }
1998 return 0;
1999 }
2000
2001 static int ssh_receive(Plug plug, int urgent, char *data, int len)
2002 {
2003 Ssh ssh = (Ssh) plug;
2004 ssh_gotdata(ssh, (unsigned char *)data, len);
2005 if (ssh->state == SSH_STATE_CLOSED) {
2006 if (ssh->s) {
2007 sk_close(ssh->s);
2008 ssh->s = NULL;
2009 }
2010 return 0;
2011 }
2012 return 1;
2013 }
2014
2015 static void ssh_sent(Plug plug, int bufsize)
2016 {
2017 Ssh ssh = (Ssh) plug;
2018 /*
2019 * If the send backlog on the SSH socket itself clears, we
2020 * should unthrottle the whole world if it was throttled.
2021 */
2022 if (bufsize < SSH_MAX_BACKLOG)
2023 ssh_throttle_all(ssh, 0, bufsize);
2024 }
2025
2026 /*
2027 * Connect to specified host and port.
2028 * Returns an error message, or NULL on success.
2029 * Also places the canonical host name into `realhost'. It must be
2030 * freed by the caller.
2031 */
2032 static char *connect_to_host(Ssh ssh, char *host, int port,
2033 char **realhost, int nodelay)
2034 {
2035 static const struct plug_function_table fn_table = {
2036 ssh_closing,
2037 ssh_receive,
2038 ssh_sent,
2039 NULL
2040 };
2041
2042 SockAddr addr;
2043 char *err;
2044
2045 ssh->savedhost = smalloc(1 + strlen(host));
2046 if (!ssh->savedhost)
2047 fatalbox("Out of memory");
2048 strcpy(ssh->savedhost, host);
2049
2050 if (port < 0)
2051 port = 22; /* default ssh port */
2052 ssh->savedport = port;
2053
2054 /*
2055 * Try to find host.
2056 */
2057 logeventf(ssh, "Looking up host \"%s\"", host);
2058 addr = name_lookup(host, port, realhost);
2059 if ((err = sk_addr_error(addr)) != NULL)
2060 return err;
2061
2062 /*
2063 * Open socket.
2064 */
2065 {
2066 char addrbuf[100];
2067 sk_getaddr(addr, addrbuf, 100);
2068 logeventf(ssh, "Connecting to %s port %d", addrbuf, port);
2069 }
2070 ssh->fn = &fn_table;
2071 ssh->s = new_connection(addr, *realhost, port, 0, 1, nodelay, (Plug) ssh);
2072 if ((err = sk_socket_error(ssh->s)) != NULL) {
2073 ssh->s = NULL;
2074 return err;
2075 }
2076
2077 return NULL;
2078 }
2079
2080 /*
2081 * Throttle or unthrottle the SSH connection.
2082 */
2083 static void ssh1_throttle(Ssh ssh, int adjust)
2084 {
2085 int old_count = ssh->v1_throttle_count;
2086 ssh->v1_throttle_count += adjust;
2087 assert(ssh->v1_throttle_count >= 0);
2088 if (ssh->v1_throttle_count && !old_count) {
2089 sk_set_frozen(ssh->s, 1);
2090 } else if (!ssh->v1_throttle_count && old_count) {
2091 sk_set_frozen(ssh->s, 0);
2092 }
2093 }
2094
2095 /*
2096 * Throttle or unthrottle _all_ local data streams (for when sends
2097 * on the SSH connection itself back up).
2098 */
2099 static void ssh_throttle_all(Ssh ssh, int enable, int bufsize)
2100 {
2101 int i;
2102 struct ssh_channel *c;
2103
2104 if (enable == ssh->throttled_all)
2105 return;
2106 ssh->throttled_all = enable;
2107 ssh->overall_bufsize = bufsize;
2108 if (!ssh->channels)
2109 return;
2110 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
2111 switch (c->type) {
2112 case CHAN_MAINSESSION:
2113 /*
2114 * This is treated separately, outside the switch.
2115 */
2116 break;
2117 case CHAN_X11:
2118 x11_override_throttle(c->u.x11.s, enable);
2119 break;
2120 case CHAN_AGENT:
2121 /* Agent channels require no buffer management. */
2122 break;
2123 case CHAN_SOCKDATA:
2124 pfd_override_throttle(c->u.x11.s, enable);
2125 break;
2126 }
2127 }
2128 }
2129
2130 /*
2131 * Username and password input, abstracted off into routines
2132 * reusable in several places - even between SSH1 and SSH2.
2133 */
2134
2135 /* Set up a username or password input loop on a given buffer. */
2136 static void setup_userpass_input(Ssh ssh, char *buffer, int buflen, int echo)
2137 {
2138 ssh->userpass_input_buffer = buffer;
2139 ssh->userpass_input_buflen = buflen;
2140 ssh->userpass_input_bufpos = 0;
2141 ssh->userpass_input_echo = echo;
2142 }
2143
2144 /*
2145 * Process some terminal data in the course of username/password
2146 * input. Returns >0 for success (line of input returned in
2147 * buffer), <0 for failure (user hit ^C/^D, bomb out and exit), 0
2148 * for inconclusive (keep waiting for more input please).
2149 */
2150 static int process_userpass_input(Ssh ssh, unsigned char *in, int inlen)
2151 {
2152 char c;
2153
2154 while (inlen--) {
2155 switch (c = *in++) {
2156 case 10:
2157 case 13:
2158 ssh->userpass_input_buffer[ssh->userpass_input_bufpos] = 0;
2159 ssh->userpass_input_buffer[ssh->userpass_input_buflen-1] = 0;
2160 return +1;
2161 break;
2162 case 8:
2163 case 127:
2164 if (ssh->userpass_input_bufpos > 0) {
2165 if (ssh->userpass_input_echo)
2166 c_write_str(ssh, "\b \b");
2167 ssh->userpass_input_bufpos--;
2168 }
2169 break;
2170 case 21:
2171 case 27:
2172 while (ssh->userpass_input_bufpos > 0) {
2173 if (ssh->userpass_input_echo)
2174 c_write_str(ssh, "\b \b");
2175 ssh->userpass_input_bufpos--;
2176 }
2177 break;
2178 case 3:
2179 case 4:
2180 return -1;
2181 break;
2182 default:
2183 if (((c >= ' ' && c <= '~') ||
2184 ((unsigned char) c >= 160))
2185 && ssh->userpass_input_bufpos < ssh->userpass_input_buflen-1) {
2186 ssh->userpass_input_buffer[ssh->userpass_input_bufpos++] = c;
2187 if (ssh->userpass_input_echo)
2188 c_write(ssh, &c, 1);
2189 }
2190 break;
2191 }
2192 }
2193 return 0;
2194 }
2195
2196 /*
2197 * Handle the key exchange and user authentication phases.
2198 */
2199 static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
2200 {
2201 int i, j;
2202 unsigned char cookie[8];
2203 struct RSAKey servkey, hostkey;
2204 struct MD5Context md5c;
2205 struct do_ssh1_login_state {
2206 int len;
2207 unsigned char *rsabuf, *keystr1, *keystr2;
2208 unsigned long supported_ciphers_mask, supported_auths_mask;
2209 int tried_publickey, tried_agent;
2210 int tis_auth_refused, ccard_auth_refused;
2211 unsigned char session_id[16];
2212 int cipher_type;
2213 char username[100];
2214 void *publickey_blob;
2215 int publickey_bloblen;
2216 char password[100];
2217 char prompt[200];
2218 int pos;
2219 char c;
2220 int pwpkt_type;
2221 unsigned char request[5], *response, *p;
2222 int responselen;
2223 int keyi, nkeys;
2224 int authed;
2225 struct RSAKey key;
2226 Bignum challenge;
2227 char *commentp;
2228 int commentlen;
2229 };
2230 crState(do_ssh1_login_state);
2231
2232 crBegin(ssh->do_ssh1_login_crstate);
2233
2234 if (!ispkt)
2235 crWaitUntil(ispkt);
2236
2237 if (ssh->pktin.type != SSH1_SMSG_PUBLIC_KEY) {
2238 bombout((ssh,"Public key packet not received"));
2239 crReturn(0);
2240 }
2241
2242 logevent("Received public keys");
2243
2244 memcpy(cookie, ssh->pktin.body, 8);
2245
2246 i = makekey(ssh->pktin.body + 8, &servkey, &s->keystr1, 0);
2247 j = makekey(ssh->pktin.body + 8 + i, &hostkey, &s->keystr2, 0);
2248
2249 /*
2250 * Log the host key fingerprint.
2251 */
2252 {
2253 char logmsg[80];
2254 logevent("Host key fingerprint is:");
2255 strcpy(logmsg, " ");
2256 hostkey.comment = NULL;
2257 rsa_fingerprint(logmsg + strlen(logmsg),
2258 sizeof(logmsg) - strlen(logmsg), &hostkey);
2259 logevent(logmsg);
2260 }
2261
2262 ssh->v1_remote_protoflags = GET_32BIT(ssh->pktin.body + 8 + i + j);
2263 s->supported_ciphers_mask = GET_32BIT(ssh->pktin.body + 12 + i + j);
2264 s->supported_auths_mask = GET_32BIT(ssh->pktin.body + 16 + i + j);
2265
2266 ssh->v1_local_protoflags =
2267 ssh->v1_remote_protoflags & SSH1_PROTOFLAGS_SUPPORTED;
2268 ssh->v1_local_protoflags |= SSH1_PROTOFLAG_SCREEN_NUMBER;
2269
2270 MD5Init(&md5c);
2271 MD5Update(&md5c, s->keystr2, hostkey.bytes);
2272 MD5Update(&md5c, s->keystr1, servkey.bytes);
2273 MD5Update(&md5c, ssh->pktin.body, 8);
2274 MD5Final(s->session_id, &md5c);
2275
2276 for (i = 0; i < 32; i++)
2277 ssh->session_key[i] = random_byte();
2278
2279 s->len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes);
2280
2281 s->rsabuf = smalloc(s->len);
2282 if (!s->rsabuf)
2283 fatalbox("Out of memory");
2284
2285 /*
2286 * Verify the host key.
2287 */
2288 {
2289 /*
2290 * First format the key into a string.
2291 */
2292 int len = rsastr_len(&hostkey);
2293 char fingerprint[100];
2294 char *keystr = smalloc(len);
2295 if (!keystr)
2296 fatalbox("Out of memory");
2297 rsastr_fmt(keystr, &hostkey);
2298 rsa_fingerprint(fingerprint, sizeof(fingerprint), &hostkey);
2299 verify_ssh_host_key(ssh->frontend,
2300 ssh->savedhost, ssh->savedport, "rsa", keystr,
2301 fingerprint);
2302 sfree(keystr);
2303 }
2304
2305 for (i = 0; i < 32; i++) {
2306 s->rsabuf[i] = ssh->session_key[i];
2307 if (i < 16)
2308 s->rsabuf[i] ^= s->session_id[i];
2309 }
2310
2311 if (hostkey.bytes > servkey.bytes) {
2312 rsaencrypt(s->rsabuf, 32, &servkey);
2313 rsaencrypt(s->rsabuf, servkey.bytes, &hostkey);
2314 } else {
2315 rsaencrypt(s->rsabuf, 32, &hostkey);
2316 rsaencrypt(s->rsabuf, hostkey.bytes, &servkey);
2317 }
2318
2319 logevent("Encrypted session key");
2320
2321 {
2322 int cipher_chosen = 0, warn = 0;
2323 char *cipher_string = NULL;
2324 int i;
2325 for (i = 0; !cipher_chosen && i < CIPHER_MAX; i++) {
2326 int next_cipher = ssh->cfg.ssh_cipherlist[i];
2327 if (next_cipher == CIPHER_WARN) {
2328 /* If/when we choose a cipher, warn about it */
2329 warn = 1;
2330 } else if (next_cipher == CIPHER_AES) {
2331 /* XXX Probably don't need to mention this. */
2332 logevent("AES not supported in SSH1, skipping");
2333 } else {
2334 switch (next_cipher) {
2335 case CIPHER_3DES: s->cipher_type = SSH_CIPHER_3DES;
2336 cipher_string = "3DES"; break;
2337 case CIPHER_BLOWFISH: s->cipher_type = SSH_CIPHER_BLOWFISH;
2338 cipher_string = "Blowfish"; break;
2339 case CIPHER_DES: s->cipher_type = SSH_CIPHER_DES;
2340 cipher_string = "single-DES"; break;
2341 }
2342 if (s->supported_ciphers_mask & (1 << s->cipher_type))
2343 cipher_chosen = 1;
2344 }
2345 }
2346 if (!cipher_chosen) {
2347 if ((s->supported_ciphers_mask & (1 << SSH_CIPHER_3DES)) == 0)
2348 bombout((ssh,"Server violates SSH 1 protocol by not "
2349 "supporting 3DES encryption"));
2350 else
2351 /* shouldn't happen */
2352 bombout((ssh,"No supported ciphers found"));
2353 crReturn(0);
2354 }
2355
2356 /* Warn about chosen cipher if necessary. */
2357 if (warn)
2358 askcipher(ssh->frontend, cipher_string, 0);
2359 }
2360
2361 switch (s->cipher_type) {
2362 case SSH_CIPHER_3DES:
2363 logevent("Using 3DES encryption");
2364 break;
2365 case SSH_CIPHER_DES:
2366 logevent("Using single-DES encryption");
2367 break;
2368 case SSH_CIPHER_BLOWFISH:
2369 logevent("Using Blowfish encryption");
2370 break;
2371 }
2372
2373 send_packet(ssh, SSH1_CMSG_SESSION_KEY,
2374 PKT_CHAR, s->cipher_type,
2375 PKT_DATA, cookie, 8,
2376 PKT_CHAR, (s->len * 8) >> 8, PKT_CHAR, (s->len * 8) & 0xFF,
2377 PKT_DATA, s->rsabuf, s->len,
2378 PKT_INT, ssh->v1_local_protoflags, PKT_END);
2379
2380 logevent("Trying to enable encryption...");
2381
2382 sfree(s->rsabuf);
2383
2384 ssh->cipher = (s->cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 :
2385 s->cipher_type == SSH_CIPHER_DES ? &ssh_des :
2386 &ssh_3des);
2387 ssh->v1_cipher_ctx = ssh->cipher->make_context();
2388 ssh->cipher->sesskey(ssh->v1_cipher_ctx, ssh->session_key);
2389 logeventf(ssh, "Initialised %s encryption", ssh->cipher->text_name);
2390
2391 ssh->crcda_ctx = crcda_make_context();
2392 logevent("Installing CRC compensation attack detector");
2393
2394 crWaitUntil(ispkt);
2395
2396 if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
2397 bombout((ssh,"Encryption not successfully enabled"));
2398 crReturn(0);
2399 }
2400
2401 logevent("Successfully started encryption");
2402
2403 fflush(stdout);
2404 {
2405 if ((flags & FLAG_INTERACTIVE) && !*ssh->cfg.username) {
2406 if (ssh_get_line && !ssh_getline_pw_only) {
2407 if (!ssh_get_line("login as: ",
2408 s->username, sizeof(s->username), FALSE)) {
2409 /*
2410 * get_line failed to get a username.
2411 * Terminate.
2412 */
2413 logevent("No username provided. Abandoning session.");
2414 ssh->state = SSH_STATE_CLOSED;
2415 crReturn(1);
2416 }
2417 } else {
2418 int ret; /* need not be kept over crReturn */
2419 c_write_str(ssh, "login as: ");
2420 ssh->send_ok = 1;
2421
2422 setup_userpass_input(ssh, s->username, sizeof(s->username), 1);
2423 do {
2424 crWaitUntil(!ispkt);
2425 ret = process_userpass_input(ssh, in, inlen);
2426 } while (ret == 0);
2427 if (ret < 0)
2428 cleanup_exit(0);
2429 c_write_str(ssh, "\r\n");
2430 }
2431 } else {
2432 strncpy(s->username, ssh->cfg.username, sizeof(s->username));
2433 s->username[sizeof(s->username)-1] = '\0';
2434 }
2435
2436 send_packet(ssh, SSH1_CMSG_USER, PKT_STR, s->username, PKT_END);
2437 {
2438 char userlog[22 + sizeof(s->username)];
2439 sprintf(userlog, "Sent username \"%s\"", s->username);
2440 logevent(userlog);
2441 if (flags & FLAG_INTERACTIVE &&
2442 (!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) {
2443 strcat(userlog, "\r\n");
2444 c_write_str(ssh, userlog);
2445 }
2446 }
2447 }
2448
2449 crWaitUntil(ispkt);
2450
2451 if ((ssh->remote_bugs & BUG_CHOKES_ON_RSA)) {
2452 /* We must not attempt PK auth. Pretend we've already tried it. */
2453 s->tried_publickey = s->tried_agent = 1;
2454 } else {
2455 s->tried_publickey = s->tried_agent = 0;
2456 }
2457 s->tis_auth_refused = s->ccard_auth_refused = 0;
2458 /* Load the public half of ssh->cfg.keyfile so we notice if it's in Pageant */
2459 if (*ssh->cfg.keyfile) {
2460 if (!rsakey_pubblob(ssh->cfg.keyfile,
2461 &s->publickey_blob, &s->publickey_bloblen))
2462 s->publickey_blob = NULL;
2463 } else
2464 s->publickey_blob = NULL;
2465
2466 while (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2467 s->pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
2468
2469 if (agent_exists() && !s->tried_agent) {
2470 /*
2471 * Attempt RSA authentication using Pageant.
2472 */
2473 void *r;
2474
2475 s->authed = FALSE;
2476 s->tried_agent = 1;
2477 logevent("Pageant is running. Requesting keys.");
2478
2479 /* Request the keys held by the agent. */
2480 PUT_32BIT(s->request, 1);
2481 s->request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES;
2482 agent_query(s->request, 5, &r, &s->responselen);
2483 s->response = (unsigned char *) r;
2484 if (s->response && s->responselen >= 5 &&
2485 s->response[4] == SSH1_AGENT_RSA_IDENTITIES_ANSWER) {
2486 s->p = s->response + 5;
2487 s->nkeys = GET_32BIT(s->p);
2488 s->p += 4;
2489 {
2490 char buf[64];
2491 sprintf(buf, "Pageant has %d SSH1 keys", s->nkeys);
2492 logevent(buf);
2493 }
2494 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
2495 {
2496 char buf[64];
2497 sprintf(buf, "Trying Pageant key #%d", s->keyi);
2498 logevent(buf);
2499 }
2500 if (s->publickey_blob &&
2501 !memcmp(s->p, s->publickey_blob,
2502 s->publickey_bloblen)) {
2503 logevent("This key matches configured key file");
2504 s->tried_publickey = 1;
2505 }
2506 s->p += 4;
2507 s->p += ssh1_read_bignum(s->p, &s->key.exponent);
2508 s->p += ssh1_read_bignum(s->p, &s->key.modulus);
2509 s->commentlen = GET_32BIT(s->p);
2510 s->p += 4;
2511 s->commentp = (char *)s->p;
2512 s->p += s->commentlen;
2513 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
2514 PKT_BIGNUM, s->key.modulus, PKT_END);
2515 crWaitUntil(ispkt);
2516 if (ssh->pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
2517 logevent("Key refused");
2518 continue;
2519 }
2520 logevent("Received RSA challenge");
2521 ssh1_read_bignum(ssh->pktin.body, &s->challenge);
2522 {
2523 char *agentreq, *q, *ret;
2524 void *vret;
2525 int len, retlen;
2526 len = 1 + 4; /* message type, bit count */
2527 len += ssh1_bignum_length(s->key.exponent);
2528 len += ssh1_bignum_length(s->key.modulus);
2529 len += ssh1_bignum_length(s->challenge);
2530 len += 16; /* session id */
2531 len += 4; /* response format */
2532 agentreq = smalloc(4 + len);
2533 PUT_32BIT(agentreq, len);
2534 q = agentreq + 4;
2535 *q++ = SSH1_AGENTC_RSA_CHALLENGE;
2536 PUT_32BIT(q, bignum_bitcount(s->key.modulus));
2537 q += 4;
2538 q += ssh1_write_bignum(q, s->key.exponent);
2539 q += ssh1_write_bignum(q, s->key.modulus);
2540 q += ssh1_write_bignum(q, s->challenge);
2541 memcpy(q, s->session_id, 16);
2542 q += 16;
2543 PUT_32BIT(q, 1); /* response format */
2544 agent_query(agentreq, len + 4, &vret, &retlen);
2545 ret = vret;
2546 sfree(agentreq);
2547 if (ret) {
2548 if (ret[4] == SSH1_AGENT_RSA_RESPONSE) {
2549 logevent("Sending Pageant's response");
2550 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
2551 PKT_DATA, ret + 5, 16,
2552 PKT_END);
2553 sfree(ret);
2554 crWaitUntil(ispkt);
2555 if (ssh->pktin.type == SSH1_SMSG_SUCCESS) {
2556 logevent
2557 ("Pageant's response accepted");
2558 if (flags & FLAG_VERBOSE) {
2559 c_write_str(ssh, "Authenticated using"
2560 " RSA key \"");
2561 c_write(ssh, s->commentp,
2562 s->commentlen);
2563 c_write_str(ssh, "\" from agent\r\n");
2564 }
2565 s->authed = TRUE;
2566 } else
2567 logevent
2568 ("Pageant's response not accepted");
2569 } else {
2570 logevent
2571 ("Pageant failed to answer challenge");
2572 sfree(ret);
2573 }
2574 } else {
2575 logevent("No reply received from Pageant");
2576 }
2577 }
2578 freebn(s->key.exponent);
2579 freebn(s->key.modulus);
2580 freebn(s->challenge);
2581 if (s->authed)
2582 break;
2583 }
2584 }
2585 if (s->authed)
2586 break;
2587 }
2588 if (*ssh->cfg.keyfile && !s->tried_publickey)
2589 s->pwpkt_type = SSH1_CMSG_AUTH_RSA;
2590
2591 if (ssh->cfg.try_tis_auth &&
2592 (s->supported_auths_mask & (1 << SSH1_AUTH_TIS)) &&
2593 !s->tis_auth_refused) {
2594 s->pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
2595 logevent("Requested TIS authentication");
2596 send_packet(ssh, SSH1_CMSG_AUTH_TIS, PKT_END);
2597 crWaitUntil(ispkt);
2598 if (ssh->pktin.type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
2599 logevent("TIS authentication declined");
2600 if (flags & FLAG_INTERACTIVE)
2601 c_write_str(ssh, "TIS authentication refused.\r\n");
2602 s->tis_auth_refused = 1;
2603 continue;
2604 } else {
2605 int challengelen = GET_32BIT(ssh->pktin.body);
2606 logevent("Received TIS challenge");
2607 if (challengelen > sizeof(s->prompt) - 1)
2608 challengelen = sizeof(s->prompt) - 1;/* prevent overrun */
2609 memcpy(s->prompt, ssh->pktin.body + 4, challengelen);
2610 /* Prompt heuristic comes from OpenSSH */
2611 strncpy(s->prompt + challengelen,
2612 memchr(s->prompt, '\n', challengelen) ?
2613 "": "\r\nResponse: ",
2614 (sizeof s->prompt) - challengelen);
2615 s->prompt[(sizeof s->prompt) - 1] = '\0';
2616 }
2617 }
2618 if (ssh->cfg.try_tis_auth &&
2619 (s->supported_auths_mask & (1 << SSH1_AUTH_CCARD)) &&
2620 !s->ccard_auth_refused) {
2621 s->pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE;
2622 logevent("Requested CryptoCard authentication");
2623 send_packet(ssh, SSH1_CMSG_AUTH_CCARD, PKT_END);
2624 crWaitUntil(ispkt);
2625 if (ssh->pktin.type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
2626 logevent("CryptoCard authentication declined");
2627 c_write_str(ssh, "CryptoCard authentication refused.\r\n");
2628 s->ccard_auth_refused = 1;
2629 continue;
2630 } else {
2631 int challengelen = GET_32BIT(ssh->pktin.body);
2632 logevent("Received CryptoCard challenge");
2633 if (challengelen > sizeof(s->prompt) - 1)
2634 challengelen = sizeof(s->prompt) - 1;/* prevent overrun */
2635 memcpy(s->prompt, ssh->pktin.body + 4, challengelen);
2636 strncpy(s->prompt + challengelen,
2637 memchr(s->prompt, '\n', challengelen) ?
2638 "" : "\r\nResponse: ",
2639 sizeof(s->prompt) - challengelen);
2640 s->prompt[sizeof(s->prompt) - 1] = '\0';
2641 }
2642 }
2643 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
2644 sprintf(s->prompt, "%.90s@%.90s's password: ",
2645 s->username, ssh->savedhost);
2646 }
2647 if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) {
2648 char *comment = NULL;
2649 int type;
2650 char msgbuf[256];
2651 if (flags & FLAG_VERBOSE)
2652 c_write_str(ssh, "Trying public key authentication.\r\n");
2653 logeventf(ssh, "Trying public key \"%s\"", ssh->cfg.keyfile);
2654 type = key_type(ssh->cfg.keyfile);
2655 if (type != SSH_KEYTYPE_SSH1) {
2656 sprintf(msgbuf, "Key is of wrong type (%s)",
2657 key_type_to_str(type));
2658 logevent(msgbuf);
2659 c_write_str(ssh, msgbuf);
2660 c_write_str(ssh, "\r\n");
2661 s->tried_publickey = 1;
2662 continue;
2663 }
2664 if (!rsakey_encrypted(ssh->cfg.keyfile, &comment)) {
2665 if (flags & FLAG_VERBOSE)
2666 c_write_str(ssh, "No passphrase required.\r\n");
2667 goto tryauth;
2668 }
2669 sprintf(s->prompt, "Passphrase for key \"%.100s\": ", comment);
2670 sfree(comment);
2671 }
2672
2673 /*
2674 * Show password prompt, having first obtained it via a TIS
2675 * or CryptoCard exchange if we're doing TIS or CryptoCard
2676 * authentication.
2677 */
2678 if (ssh_get_line) {
2679 if (!ssh_get_line(s->prompt, s->password,
2680 sizeof(s->password), TRUE)) {
2681 /*
2682 * get_line failed to get a password (for example
2683 * because one was supplied on the command line
2684 * which has already failed to work). Terminate.
2685 */
2686 send_packet(ssh, SSH1_MSG_DISCONNECT,
2687 PKT_STR, "No more passwords available to try",
2688 PKT_END);
2689 logevent("Unable to authenticate");
2690 connection_fatal(ssh->frontend, "Unable to authenticate");
2691 ssh->state = SSH_STATE_CLOSED;
2692 crReturn(1);
2693 }
2694 } else {
2695 /* Prompt may have come from server. We've munged it a bit, so
2696 * we know it to be zero-terminated at least once. */
2697 int ret; /* need not be saved over crReturn */
2698 c_write_untrusted(ssh, s->prompt, strlen(s->prompt));
2699 s->pos = 0;
2700
2701 setup_userpass_input(ssh, s->password, sizeof(s->password), 0);
2702 do {
2703 crWaitUntil(!ispkt);
2704 ret = process_userpass_input(ssh, in, inlen);
2705 } while (ret == 0);
2706 if (ret < 0)
2707 cleanup_exit(0);
2708 c_write_str(ssh, "\r\n");
2709 }
2710
2711 tryauth:
2712 if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) {
2713 /*
2714 * Try public key authentication with the specified
2715 * key file.
2716 */
2717 s->tried_publickey = 1;
2718
2719 {
2720 int ret = loadrsakey(ssh->cfg.keyfile, &s->key, s->password);
2721 if (ret == 0) {
2722 c_write_str(ssh, "Couldn't load private key from ");
2723 c_write_str(ssh, ssh->cfg.keyfile);
2724 c_write_str(ssh, ".\r\n");
2725 continue; /* go and try password */
2726 }
2727 if (ret == -1) {
2728 c_write_str(ssh, "Wrong passphrase.\r\n");
2729 s->tried_publickey = 0;
2730 continue; /* try again */
2731 }
2732 }
2733
2734 /*
2735 * Send a public key attempt.
2736 */
2737 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
2738 PKT_BIGNUM, s->key.modulus, PKT_END);
2739
2740 crWaitUntil(ispkt);
2741 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2742 c_write_str(ssh, "Server refused our public key.\r\n");
2743 continue; /* go and try password */
2744 }
2745 if (ssh->pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
2746 bombout((ssh,"Bizarre response to offer of public key"));
2747 crReturn(0);
2748 }
2749
2750 {
2751 int i;
2752 unsigned char buffer[32];
2753 Bignum challenge, response;
2754
2755 ssh1_read_bignum(ssh->pktin.body, &challenge);
2756 response = rsadecrypt(challenge, &s->key);
2757 freebn(s->key.private_exponent);/* burn the evidence */
2758
2759 for (i = 0; i < 32; i++) {
2760 buffer[i] = bignum_byte(response, 31 - i);
2761 }
2762
2763 MD5Init(&md5c);
2764 MD5Update(&md5c, buffer, 32);
2765 MD5Update(&md5c, s->session_id, 16);
2766 MD5Final(buffer, &md5c);
2767
2768 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
2769 PKT_DATA, buffer, 16, PKT_END);
2770
2771 freebn(challenge);
2772 freebn(response);
2773 }
2774
2775 crWaitUntil(ispkt);
2776 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2777 if (flags & FLAG_VERBOSE)
2778 c_write_str(ssh, "Failed to authenticate with"
2779 " our public key.\r\n");
2780 continue; /* go and try password */
2781 } else if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
2782 bombout((ssh,"Bizarre response to RSA authentication response"));
2783 crReturn(0);
2784 }
2785
2786 break; /* we're through! */
2787 } else {
2788 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
2789 /*
2790 * Defence against traffic analysis: we send a
2791 * whole bunch of packets containing strings of
2792 * different lengths. One of these strings is the
2793 * password, in a SSH1_CMSG_AUTH_PASSWORD packet.
2794 * The others are all random data in
2795 * SSH1_MSG_IGNORE packets. This way a passive
2796 * listener can't tell which is the password, and
2797 * hence can't deduce the password length.
2798 *
2799 * Anybody with a password length greater than 16
2800 * bytes is going to have enough entropy in their
2801 * password that a listener won't find it _that_
2802 * much help to know how long it is. So what we'll
2803 * do is:
2804 *
2805 * - if password length < 16, we send 15 packets
2806 * containing string lengths 1 through 15
2807 *
2808 * - otherwise, we let N be the nearest multiple
2809 * of 8 below the password length, and send 8
2810 * packets containing string lengths N through
2811 * N+7. This won't obscure the order of
2812 * magnitude of the password length, but it will
2813 * introduce a bit of extra uncertainty.
2814 *
2815 * A few servers (the old 1.2.18 through 1.2.22)
2816 * can't deal with SSH1_MSG_IGNORE. For these
2817 * servers, we need an alternative defence. We make
2818 * use of the fact that the password is interpreted
2819 * as a C string: so we can append a NUL, then some
2820 * random data.
2821 *
2822 * One server (a Cisco one) can deal with neither
2823 * SSH1_MSG_IGNORE _nor_ a padded password string.
2824 * For this server we are left with no defences
2825 * against password length sniffing.
2826 */
2827 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE)) {
2828 /*
2829 * The server can deal with SSH1_MSG_IGNORE, so
2830 * we can use the primary defence.
2831 */
2832 int bottom, top, pwlen, i;
2833 char *randomstr;
2834
2835 pwlen = strlen(s->password);
2836 if (pwlen < 16) {
2837 bottom = 0; /* zero length passwords are OK! :-) */
2838 top = 15;
2839 } else {
2840 bottom = pwlen & ~7;
2841 top = bottom + 7;
2842 }
2843
2844 assert(pwlen >= bottom && pwlen <= top);
2845
2846 randomstr = smalloc(top + 1);
2847
2848 for (i = bottom; i <= top; i++) {
2849 if (i == pwlen)
2850 defer_packet(ssh, s->pwpkt_type,
2851 PKT_STR, s->password, PKT_END);
2852 else {
2853 for (j = 0; j < i; j++) {
2854 do {
2855 randomstr[j] = random_byte();
2856 } while (randomstr[j] == '\0');
2857 }
2858 randomstr[i] = '\0';
2859 defer_packet(ssh, SSH1_MSG_IGNORE,
2860 PKT_STR, randomstr, PKT_END);
2861 }
2862 }
2863 logevent("Sending password with camouflage packets");
2864 ssh_pkt_defersend(ssh);
2865 }
2866 else if (!(ssh->remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) {
2867 /*
2868 * The server can't deal with SSH1_MSG_IGNORE
2869 * but can deal with padded passwords, so we
2870 * can use the secondary defence.
2871 */
2872 char string[64];
2873 char *ss;
2874 int len;
2875
2876 len = strlen(s->password);
2877 if (len < sizeof(string)) {
2878 ss = string;
2879 strcpy(string, s->password);
2880 len++; /* cover the zero byte */
2881 while (len < sizeof(string)) {
2882 string[len++] = (char) random_byte();
2883 }
2884 } else {
2885 ss = s->password;
2886 }
2887 logevent("Sending length-padded password");
2888 send_packet(ssh, s->pwpkt_type, PKT_INT, len,
2889 PKT_DATA, ss, len, PKT_END);
2890 } else {
2891 /*
2892 * The server has _both_
2893 * BUG_CHOKES_ON_SSH1_IGNORE and
2894 * BUG_NEEDS_SSH1_PLAIN_PASSWORD. There is
2895 * therefore nothing we can do.
2896 */
2897 int len;
2898 len = strlen(s->password);
2899 logevent("Sending unpadded password");
2900 send_packet(ssh, s->pwpkt_type, PKT_INT, len,
2901 PKT_DATA, s->password, len, PKT_END);
2902 }
2903 } else {
2904 send_packet(ssh, s->pwpkt_type, PKT_STR, s->password, PKT_END);
2905 }
2906 }
2907 logevent("Sent password");
2908 memset(s->password, 0, strlen(s->password));
2909 crWaitUntil(ispkt);
2910 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2911 if (flags & FLAG_VERBOSE)
2912 c_write_str(ssh, "Access denied\r\n");
2913 logevent("Authentication refused");
2914 } else if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
2915 bombout((ssh,"Strange packet received, type %d", ssh->pktin.type));
2916 crReturn(0);
2917 }
2918 }
2919
2920 logevent("Authentication successful");
2921
2922 crFinish(1);
2923 }
2924
2925 void sshfwd_close(struct ssh_channel *c)
2926 {
2927 Ssh ssh = c->ssh;
2928
2929 if (c && !c->closes) {
2930 /*
2931 * If the channel's remoteid is -1, we have sent
2932 * CHANNEL_OPEN for this channel, but it hasn't even been
2933 * acknowledged by the server. So we must set a close flag
2934 * on it now, and then when the server acks the channel
2935 * open, we can close it then.
2936 */
2937 if (((int)c->remoteid) != -1) {
2938 if (ssh->version == 1) {
2939 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid,
2940 PKT_END);
2941 } else {
2942 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
2943 ssh2_pkt_adduint32(ssh, c->remoteid);
2944 ssh2_pkt_send(ssh);
2945 }
2946 }
2947 c->closes = 1; /* sent MSG_CLOSE */
2948 if (c->type == CHAN_X11) {
2949 c->u.x11.s = NULL;
2950 logevent("Forwarded X11 connection terminated");
2951 } else if (c->type == CHAN_SOCKDATA ||
2952 c->type == CHAN_SOCKDATA_DORMANT) {
2953 c->u.pfd.s = NULL;
2954 logevent("Forwarded port closed");
2955 }
2956 }
2957 }
2958
2959 int sshfwd_write(struct ssh_channel *c, char *buf, int len)
2960 {
2961 Ssh ssh = c->ssh;
2962
2963 if (ssh->version == 1) {
2964 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
2965 PKT_INT, c->remoteid,
2966 PKT_INT, len, PKT_DATA, buf, len, PKT_END);
2967 /*
2968 * In SSH1 we can return 0 here - implying that forwarded
2969 * connections are never individually throttled - because
2970 * the only circumstance that can cause throttling will be
2971 * the whole SSH connection backing up, in which case
2972 * _everything_ will be throttled as a whole.
2973 */
2974 return 0;
2975 } else {
2976 ssh2_add_channel_data(c, buf, len);
2977 return ssh2_try_send(c);
2978 }
2979 }
2980
2981 void sshfwd_unthrottle(struct ssh_channel *c, int bufsize)
2982 {
2983 Ssh ssh = c->ssh;
2984
2985 if (ssh->version == 1) {
2986 if (c->v.v1.throttling && bufsize < SSH1_BUFFER_LIMIT) {
2987 c->v.v1.throttling = 0;
2988 ssh1_throttle(ssh, -1);
2989 }
2990 } else {
2991 ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
2992 }
2993 }
2994
2995 static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
2996 {
2997 crBegin(ssh->ssh1_protocol_crstate);
2998
2999 random_init();
3000
3001 while (!do_ssh1_login(ssh, in, inlen, ispkt)) {
3002 crReturnV;
3003 }
3004 if (ssh->state == SSH_STATE_CLOSED)
3005 crReturnV;
3006
3007 if (ssh->cfg.agentfwd && agent_exists()) {
3008 logevent("Requesting agent forwarding");
3009 send_packet(ssh, SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END);
3010 do {
3011 crReturnV;
3012 } while (!ispkt);
3013 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3014 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3015 bombout((ssh,"Protocol confusion"));
3016 crReturnV;
3017 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3018 logevent("Agent forwarding refused");
3019 } else {
3020 logevent("Agent forwarding enabled");
3021 ssh->agentfwd_enabled = TRUE;
3022 }
3023 }
3024
3025 if (ssh->cfg.x11_forward) {
3026 char proto[20], data[64];
3027 logevent("Requesting X11 forwarding");
3028 ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
3029 data, sizeof(data), ssh->cfg.x11_auth);
3030 x11_get_real_auth(ssh->x11auth, ssh->cfg.x11_display);
3031 if (ssh->v1_local_protoflags & SSH1_PROTOFLAG_SCREEN_NUMBER) {
3032 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
3033 PKT_STR, proto, PKT_STR, data,
3034 PKT_INT, x11_get_screen_number(ssh->cfg.x11_display),
3035 PKT_END);
3036 } else {
3037 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
3038 PKT_STR, proto, PKT_STR, data, PKT_END);
3039 }
3040 do {
3041 crReturnV;
3042 } while (!ispkt);
3043 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3044 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3045 bombout((ssh,"Protocol confusion"));
3046 crReturnV;
3047 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3048 logevent("X11 forwarding refused");
3049 } else {
3050 logevent("X11 forwarding enabled");
3051 ssh->X11_fwd_enabled = TRUE;
3052 }
3053 }
3054
3055 {
3056 char type;
3057 int n;
3058 int sport,dport,sserv,dserv;
3059 char sports[256], dports[256], saddr[256], host[256];
3060
3061 ssh->rportfwds = newtree234(ssh_rportcmp_ssh1);
3062 /* Add port forwardings. */
3063 ssh->portfwd_strptr = ssh->cfg.portfwd;
3064 while (*ssh->portfwd_strptr) {
3065 type = *ssh->portfwd_strptr++;
3066 saddr[0] = '\0';
3067 n = 0;
3068 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != '\t') {
3069 if (*ssh->portfwd_strptr == ':') {
3070 /*
3071 * We've seen a colon in the middle of the
3072 * source port number. This means that
3073 * everything we've seen until now is the
3074 * source _address_, so we'll move it into
3075 * saddr and start sports from the beginning
3076 * again.
3077 */
3078 ssh->portfwd_strptr++;
3079 sports[n] = '\0';
3080 strcpy(saddr, sports);
3081 n = 0;
3082 }
3083 if (n < 255) sports[n++] = *ssh->portfwd_strptr++;
3084 }
3085 sports[n] = 0;
3086 if (*ssh->portfwd_strptr == '\t')
3087 ssh->portfwd_strptr++;
3088 n = 0;
3089 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':') {
3090 if (n < 255) host[n++] = *ssh->portfwd_strptr++;
3091 }
3092 host[n] = 0;
3093 if (*ssh->portfwd_strptr == ':')
3094 ssh->portfwd_strptr++;
3095 n = 0;
3096 while (*ssh->portfwd_strptr) {
3097 if (n < 255) dports[n++] = *ssh->portfwd_strptr++;
3098 }
3099 dports[n] = 0;
3100 ssh->portfwd_strptr++;
3101 dport = atoi(dports);
3102 dserv = 0;
3103 if (dport == 0) {
3104 dserv = 1;
3105 dport = net_service_lookup(dports);
3106 if (!dport) {
3107 logeventf(ssh, "Service lookup failed for"
3108 " destination port \"%s\"", dports);
3109 }
3110 }
3111 sport = atoi(sports);
3112 sserv = 0;
3113 if (sport == 0) {
3114 sserv = 1;
3115 sport = net_service_lookup(sports);
3116 if (!sport) {
3117 logeventf(ssh, "Service lookup failed for source"
3118 " port \"%s\"", sports);
3119 }
3120 }
3121 if (sport && dport) {
3122 if (type == 'L') {
3123 pfd_addforward(host, dport, *saddr ? saddr : NULL,
3124 sport, ssh, ssh->cfg.lport_acceptall);
3125 logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
3126 " forwarding to %s:%.*s%.*s%d%.*s",
3127 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
3128 (int)(*saddr?1:0), ":",
3129 (int)(sserv ? strlen(sports) : 0), sports,
3130 sserv, "(", sport, sserv, ")",
3131 host,
3132 (int)(dserv ? strlen(dports) : 0), dports,
3133 dserv, "(", dport, dserv, ")");
3134 } else {
3135 struct ssh_rportfwd *pf;
3136 pf = smalloc(sizeof(*pf));
3137 strcpy(pf->dhost, host);
3138 pf->dport = dport;
3139 if (saddr) {
3140 logeventf(ssh,
3141 "SSH1 cannot handle source address spec \"%s:%d\"; ignoring",
3142 saddr, sport);
3143 }
3144 if (add234(ssh->rportfwds, pf) != pf) {
3145 logeventf(ssh,
3146 "Duplicate remote port forwarding to %s:%d",
3147 host, dport);
3148 sfree(pf);
3149 } else {
3150 logeventf(ssh, "Requesting remote port %.*s%.*s%d%.*s"
3151 " forward to %s:%.*s%.*s%d%.*s",
3152 (int)(sserv ? strlen(sports) : 0), sports,
3153 sserv, "(", sport, sserv, ")",
3154 host,
3155 (int)(dserv ? strlen(dports) : 0), dports,
3156 dserv, "(", dport, dserv, ")");
3157 send_packet(ssh, SSH1_CMSG_PORT_FORWARD_REQUEST,
3158 PKT_INT, sport,
3159 PKT_STR, host,
3160 PKT_INT, dport,
3161 PKT_END);
3162 do {
3163 crReturnV;
3164 } while (!ispkt);
3165 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3166 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3167 bombout((ssh,"Protocol confusion"));
3168 crReturnV;
3169 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3170 c_write_str(ssh, "Server refused port"
3171 " forwarding\r\n");
3172 }
3173 logevent("Remote port forwarding enabled");
3174 }
3175 }
3176 }
3177 }
3178 }
3179
3180 if (!ssh->cfg.nopty) {
3181 send_packet(ssh, SSH1_CMSG_REQUEST_PTY,
3182 PKT_STR, ssh->cfg.termtype,
3183 PKT_INT, ssh->term_height,
3184 PKT_INT, ssh->term_width,
3185 PKT_INT, 0, PKT_INT, 0, PKT_CHAR, 0, PKT_END);
3186 ssh->state = SSH_STATE_INTERMED;
3187 do {
3188 crReturnV;
3189 } while (!ispkt);
3190 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3191 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3192 bombout((ssh,"Protocol confusion"));
3193 crReturnV;
3194 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3195 c_write_str(ssh, "Server refused to allocate pty\r\n");
3196 ssh->editing = ssh->echoing = 1;
3197 }
3198 logevent("Allocated pty");
3199 } else {
3200 ssh->editing = ssh->echoing = 1;
3201 }
3202
3203 if (ssh->cfg.compression) {
3204 send_packet(ssh, SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END);
3205 do {
3206 crReturnV;
3207 } while (!ispkt);
3208 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3209 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3210 bombout((ssh,"Protocol confusion"));
3211 crReturnV;
3212 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3213 c_write_str(ssh, "Server refused to compress\r\n");
3214 }
3215 logevent("Started compression");
3216 ssh->v1_compressing = TRUE;
3217 ssh->cs_comp_ctx = zlib_compress_init();
3218 logevent("Initialised zlib (RFC1950) compression");
3219 ssh->sc_comp_ctx = zlib_decompress_init();
3220 logevent("Initialised zlib (RFC1950) decompression");
3221 }
3222
3223 /*
3224 * Start the shell or command.
3225 *
3226 * Special case: if the first-choice command is an SSH2
3227 * subsystem (hence not usable here) and the second choice
3228 * exists, we fall straight back to that.
3229 */
3230 {
3231 char *cmd = ssh->cfg.remote_cmd_ptr;
3232
3233 if (ssh->cfg.ssh_subsys && ssh->cfg.remote_cmd_ptr2) {
3234 cmd = ssh->cfg.remote_cmd_ptr2;
3235 ssh->fallback_cmd = TRUE;
3236 }
3237 if (*cmd)
3238 send_packet(ssh, SSH1_CMSG_EXEC_CMD, PKT_STR, cmd, PKT_END);
3239 else
3240 send_packet(ssh, SSH1_CMSG_EXEC_SHELL, PKT_END);
3241 logevent("Started session");
3242 }
3243
3244 ssh->state = SSH_STATE_SESSION;
3245 if (ssh->size_needed)
3246 ssh_size(ssh, ssh->term_width, ssh->term_height);
3247 if (ssh->eof_needed)
3248 ssh_special(ssh, TS_EOF);
3249
3250 if (ssh->ldisc)
3251 ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */
3252 ssh->send_ok = 1;
3253 ssh->channels = newtree234(ssh_channelcmp);
3254 while (1) {
3255 crReturnV;
3256 if (ispkt) {
3257 if (ssh->pktin.type == SSH1_SMSG_STDOUT_DATA ||
3258 ssh->pktin.type == SSH1_SMSG_STDERR_DATA) {
3259 long len = GET_32BIT(ssh->pktin.body);
3260 int bufsize =
3261 from_backend(ssh->frontend,
3262 ssh->pktin.type == SSH1_SMSG_STDERR_DATA,
3263 (char *)(ssh->pktin.body) + 4, len);
3264 if (!ssh->v1_stdout_throttling && bufsize > SSH1_BUFFER_LIMIT) {
3265 ssh->v1_stdout_throttling = 1;
3266 ssh1_throttle(ssh, +1);
3267 }
3268 } else if (ssh->pktin.type == SSH1_MSG_DISCONNECT) {
3269 ssh->state = SSH_STATE_CLOSED;
3270 logevent("Received disconnect request");
3271 crReturnV;
3272 } else if (ssh->pktin.type == SSH1_SMSG_X11_OPEN) {
3273 /* Remote side is trying to open a channel to talk to our
3274 * X-Server. Give them back a local channel number. */
3275 struct ssh_channel *c;
3276
3277 logevent("Received X11 connect request");
3278 /* Refuse if X11 forwarding is disabled. */
3279 if (!ssh->X11_fwd_enabled) {
3280 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3281 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
3282 logevent("Rejected X11 connect request");
3283 } else {
3284 c = smalloc(sizeof(struct ssh_channel));
3285 c->ssh = ssh;
3286
3287 if (x11_init(&c->u.x11.s, ssh->cfg.x11_display, c,
3288 ssh->x11auth, NULL, -1) != NULL) {
3289 logevent("opening X11 forward connection failed");
3290 sfree(c);
3291 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3292 PKT_INT, GET_32BIT(ssh->pktin.body),
3293 PKT_END);
3294 } else {
3295 logevent
3296 ("opening X11 forward connection succeeded");
3297 c->remoteid = GET_32BIT(ssh->pktin.body);
3298 c->localid = alloc_channel_id(ssh);
3299 c->closes = 0;
3300 c->v.v1.throttling = 0;
3301 c->type = CHAN_X11; /* identify channel type */
3302 add234(ssh->channels, c);
3303 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3304 PKT_INT, c->remoteid, PKT_INT,
3305 c->localid, PKT_END);
3306 logevent("Opened X11 forward channel");
3307 }
3308 }
3309 } else if (ssh->pktin.type == SSH1_SMSG_AGENT_OPEN) {
3310 /* Remote side is trying to open a channel to talk to our
3311 * agent. Give them back a local channel number. */
3312 struct ssh_channel *c;
3313
3314 /* Refuse if agent forwarding is disabled. */
3315 if (!ssh->agentfwd_enabled) {
3316 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3317 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
3318 } else {
3319 c = smalloc(sizeof(struct ssh_channel));
3320 c->ssh = ssh;
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_AGENT; /* identify channel type */
3326 c->u.a.lensofar = 0;
3327 add234(ssh->channels, c);
3328 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3329 PKT_INT, c->remoteid, PKT_INT, c->localid,
3330 PKT_END);
3331 }
3332 } else if (ssh->pktin.type == SSH1_MSG_PORT_OPEN) {
3333 /* Remote side is trying to open a channel to talk to a
3334 * forwarded port. Give them back a local channel number. */
3335 struct ssh_channel *c;
3336 struct ssh_rportfwd pf;
3337 int hostsize, port;
3338 char host[256], buf[1024];
3339 char *p, *h, *e;
3340 c = smalloc(sizeof(struct ssh_channel));
3341 c->ssh = ssh;
3342
3343 hostsize = GET_32BIT(ssh->pktin.body+4);
3344 for (h = host, p = (char *)(ssh->pktin.body+8);
3345 hostsize != 0; hostsize--) {
3346 if (h+1 < host+sizeof(host))
3347 *h++ = *p;
3348 p++;
3349 }
3350 *h = 0;
3351 port = GET_32BIT(p);
3352
3353 strcpy(pf.dhost, host);
3354 pf.dport = port;
3355
3356 if (find234(ssh->rportfwds, &pf, NULL) == NULL) {
3357 sprintf(buf, "Rejected remote port open request for %s:%d",
3358 host, port);
3359 logevent(buf);
3360 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3361 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
3362 } else {
3363 sprintf(buf, "Received remote port open request for %s:%d",
3364 host, port);
3365 logevent(buf);
3366 e = pfd_newconnect(&c->u.pfd.s, host, port, c);
3367 if (e != NULL) {
3368 char buf[256];
3369 sprintf(buf, "Port open failed: %s", e);
3370 logevent(buf);
3371 sfree(c);
3372 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3373 PKT_INT, GET_32BIT(ssh->pktin.body),
3374 PKT_END);
3375 } else {
3376 c->remoteid = GET_32BIT(ssh->pktin.body);
3377 c->localid = alloc_channel_id(ssh);
3378 c->closes = 0;
3379 c->v.v1.throttling = 0;
3380 c->type = CHAN_SOCKDATA; /* identify channel type */
3381 add234(ssh->channels, c);
3382 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3383 PKT_INT, c->remoteid, PKT_INT,
3384 c->localid, PKT_END);
3385 logevent("Forwarded port opened successfully");
3386 }
3387 }
3388
3389 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_OPEN_CONFIRMATION) {
3390 unsigned int remoteid = GET_32BIT(ssh->pktin.body);
3391 unsigned int localid = GET_32BIT(ssh->pktin.body+4);
3392 struct ssh_channel *c;
3393
3394 c = find234(ssh->channels, &remoteid, ssh_channelfind);
3395 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
3396 c->remoteid = localid;
3397 c->type = CHAN_SOCKDATA;
3398 c->v.v1.throttling = 0;
3399 pfd_confirm(c->u.pfd.s);
3400 }
3401
3402 if (c && c->closes) {
3403 /*
3404 * We have a pending close on this channel,
3405 * which we decided on before the server acked
3406 * the channel open. So now we know the
3407 * remoteid, we can close it again.
3408 */
3409 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE,
3410 PKT_INT, c->remoteid, PKT_END);
3411 }
3412
3413 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_OPEN_FAILURE) {
3414 unsigned int remoteid = GET_32BIT(ssh->pktin.body);
3415 struct ssh_channel *c;
3416
3417 c = find234(ssh->channels, &remoteid, ssh_channelfind);
3418 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
3419 logevent("Forwarded connection refused by server");
3420 pfd_close(c->u.pfd.s);
3421 del234(ssh->channels, c);
3422 sfree(c);
3423 }
3424
3425 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ||
3426 ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION) {
3427 /* Remote side closes a channel. */
3428 unsigned i = GET_32BIT(ssh->pktin.body);
3429 struct ssh_channel *c;
3430 c = find234(ssh->channels, &i, ssh_channelfind);
3431 if (c && ((int)c->remoteid) != -1) {
3432 int closetype;
3433 closetype =
3434 (ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ? 1 : 2);
3435
3436 if ((c->closes == 0) && (c->type == CHAN_X11)) {
3437 logevent("Forwarded X11 connection terminated");
3438 assert(c->u.x11.s != NULL);
3439 x11_close(c->u.x11.s);
3440 c->u.x11.s = NULL;
3441 }
3442 if ((c->closes == 0) && (c->type == CHAN_SOCKDATA)) {
3443 logevent("Forwarded port closed");
3444 assert(c->u.pfd.s != NULL);
3445 pfd_close(c->u.pfd.s);
3446 c->u.pfd.s = NULL;
3447 }
3448
3449 c->closes |= (closetype << 2); /* seen this message */
3450 if (!(c->closes & closetype)) {
3451 send_packet(ssh, ssh->pktin.type, PKT_INT, c->remoteid,
3452 PKT_END);
3453 c->closes |= closetype; /* sent it too */
3454 }
3455
3456 if (c->closes == 15) {
3457 del234(ssh->channels, c);
3458 sfree(c);
3459 }
3460 } else {
3461 bombout((ssh,"Received CHANNEL_CLOSE%s for %s channel %d\n",
3462 ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ? "" :
3463 "_CONFIRMATION", c ? "half-open" : "nonexistent",
3464 i));
3465 }
3466 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_DATA) {
3467 /* Data sent down one of our channels. */
3468 int i = GET_32BIT(ssh->pktin.body);
3469 int len = GET_32BIT(ssh->pktin.body + 4);
3470 unsigned char *p = ssh->pktin.body + 8;
3471 struct ssh_channel *c;
3472 c = find234(ssh->channels, &i, ssh_channelfind);
3473 if (c) {
3474 int bufsize;
3475 switch (c->type) {
3476 case CHAN_X11:
3477 bufsize = x11_send(c->u.x11.s, (char *)p, len);
3478 break;
3479 case CHAN_SOCKDATA:
3480 bufsize = pfd_send(c->u.pfd.s, (char *)p, len);
3481 break;
3482 case CHAN_AGENT:
3483 /* Data for an agent message. Buffer it. */
3484 while (len > 0) {
3485 if (c->u.a.lensofar < 4) {
3486 int l = min(4 - c->u.a.lensofar, len);
3487 memcpy(c->u.a.msglen + c->u.a.lensofar, p,
3488 l);
3489 p += l;
3490 len -= l;
3491 c->u.a.lensofar += l;
3492 }
3493 if (c->u.a.lensofar == 4) {
3494 c->u.a.totallen =
3495 4 + GET_32BIT(c->u.a.msglen);
3496 c->u.a.message = smalloc(c->u.a.totallen);
3497 memcpy(c->u.a.message, c->u.a.msglen, 4);
3498 }
3499 if (c->u.a.lensofar >= 4 && len > 0) {
3500 int l =
3501 min(c->u.a.totallen - c->u.a.lensofar,
3502 len);
3503 memcpy(c->u.a.message + c->u.a.lensofar, p,
3504 l);
3505 p += l;
3506 len -= l;
3507 c->u.a.lensofar += l;
3508 }
3509 if (c->u.a.lensofar == c->u.a.totallen) {
3510 void *reply, *sentreply;
3511 int replylen;
3512 agent_query(c->u.a.message,
3513 c->u.a.totallen, &reply,
3514 &replylen);
3515 if (reply)
3516 sentreply = reply;
3517 else {
3518 /* Fake SSH_AGENT_FAILURE. */
3519 sentreply = "\0\0\0\1\5";
3520 replylen = 5;
3521 }
3522 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
3523 PKT_INT, c->remoteid,
3524 PKT_INT, replylen,
3525 PKT_DATA, sentreply, replylen,
3526 PKT_END);
3527 if (reply)
3528 sfree(reply);
3529 sfree(c->u.a.message);
3530 c->u.a.lensofar = 0;
3531 }
3532 }
3533 bufsize = 0; /* agent channels never back up */
3534 break;
3535 }
3536 if (!c->v.v1.throttling && bufsize > SSH1_BUFFER_LIMIT) {
3537 c->v.v1.throttling = 1;
3538 ssh1_throttle(ssh, +1);
3539 }
3540 }
3541 } else if (ssh->pktin.type == SSH1_SMSG_SUCCESS) {
3542 /* may be from EXEC_SHELL on some servers */
3543 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3544 /* may be from EXEC_SHELL on some servers
3545 * if no pty is available or in other odd cases. Ignore */
3546 } else if (ssh->pktin.type == SSH1_SMSG_EXIT_STATUS) {
3547 char buf[100];
3548 ssh->exitcode = GET_32BIT(ssh->pktin.body);
3549 sprintf(buf, "Server sent command exit status %d",
3550 ssh->exitcode);
3551 logevent(buf);
3552 send_packet(ssh, SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
3553 /*
3554 * In case `helpful' firewalls or proxies tack
3555 * extra human-readable text on the end of the
3556 * session which we might mistake for another
3557 * encrypted packet, we close the session once
3558 * we've sent EXIT_CONFIRMATION.
3559 */
3560 ssh->state = SSH_STATE_CLOSED;
3561 crReturnV;
3562 } else {
3563 bombout((ssh,"Strange packet received: type %d", ssh->pktin.type));
3564 crReturnV;
3565 }
3566 } else {
3567 while (inlen > 0) {
3568 int len = min(inlen, 512);
3569 send_packet(ssh, SSH1_CMSG_STDIN_DATA,
3570 PKT_INT, len, PKT_DATA, in, len, PKT_END);
3571 in += len;
3572 inlen -= len;
3573 }
3574 }
3575 }
3576
3577 crFinishV;
3578 }
3579
3580 /*
3581 * Utility routine for decoding comma-separated strings in KEXINIT.
3582 */
3583 static int in_commasep_string(char *needle, char *haystack, int haylen)
3584 {
3585 int needlen;
3586 if (!needle || !haystack) /* protect against null pointers */
3587 return 0;
3588 needlen = strlen(needle);
3589 while (1) {
3590 /*
3591 * Is it at the start of the string?
3592 */
3593 if (haylen >= needlen && /* haystack is long enough */
3594 !memcmp(needle, haystack, needlen) && /* initial match */
3595 (haylen == needlen || haystack[needlen] == ',')
3596 /* either , or EOS follows */
3597 )
3598 return 1;
3599 /*
3600 * If not, search for the next comma and resume after that.
3601 * If no comma found, terminate.
3602 */
3603 while (haylen > 0 && *haystack != ',')
3604 haylen--, haystack++;
3605 if (haylen == 0)
3606 return 0;
3607 haylen--, haystack++; /* skip over comma itself */
3608 }
3609 }
3610
3611 /*
3612 * SSH2 key creation method.
3613 */
3614 static void ssh2_mkkey(Ssh ssh, Bignum K, unsigned char *H,
3615 unsigned char *sessid, char chr,
3616 unsigned char *keyspace)
3617 {
3618 SHA_State s;
3619 /* First 20 bytes. */
3620 SHA_Init(&s);
3621 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
3622 sha_mpint(&s, K);
3623 SHA_Bytes(&s, H, 20);
3624 SHA_Bytes(&s, &chr, 1);
3625 SHA_Bytes(&s, sessid, 20);
3626 SHA_Final(&s, keyspace);
3627 /* Next 20 bytes. */
3628 SHA_Init(&s);
3629 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
3630 sha_mpint(&s, K);
3631 SHA_Bytes(&s, H, 20);
3632 SHA_Bytes(&s, keyspace, 20);
3633 SHA_Final(&s, keyspace + 20);
3634 }
3635
3636 /*
3637 * Handle the SSH2 transport layer.
3638 */
3639 static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
3640 {
3641 struct do_ssh2_transport_state {
3642 int nbits, pbits, warn;
3643 Bignum p, g, e, f, K;
3644 int kex_init_value, kex_reply_value;
3645 const struct ssh_mac **maclist;
3646 int nmacs;
3647 const struct ssh2_cipher *cscipher_tobe;
3648 const struct ssh2_cipher *sccipher_tobe;
3649 const struct ssh_mac *csmac_tobe;
3650 const struct ssh_mac *scmac_tobe;
3651 const struct ssh_compress *cscomp_tobe;
3652 const struct ssh_compress *sccomp_tobe;
3653 char *hostkeydata, *sigdata, *keystr, *fingerprint;
3654 int hostkeylen, siglen;
3655 void *hkey; /* actual host key */
3656 unsigned char exchange_hash[20];
3657 int n_preferred_ciphers;
3658 const struct ssh2_ciphers *preferred_ciphers[CIPHER_MAX];
3659 const struct ssh_compress *preferred_comp;
3660 int first_kex;
3661 };
3662 crState(do_ssh2_transport_state);
3663
3664 crBegin(ssh->do_ssh2_transport_crstate);
3665
3666 s->cscipher_tobe = s->sccipher_tobe = NULL;
3667 s->csmac_tobe = s->scmac_tobe = NULL;
3668 s->cscomp_tobe = s->sccomp_tobe = NULL;
3669
3670 random_init();
3671 s->first_kex = 1;
3672
3673 {
3674 int i;
3675 /*
3676 * Set up the preferred ciphers. (NULL => warn below here)
3677 */
3678 s->n_preferred_ciphers = 0;
3679 for (i = 0; i < CIPHER_MAX; i++) {
3680 switch (ssh->cfg.ssh_cipherlist[i]) {
3681 case CIPHER_BLOWFISH:
3682 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_blowfish;
3683 break;
3684 case CIPHER_DES:
3685 if (ssh->cfg.ssh2_des_cbc) {
3686 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_des;
3687 }
3688 break;
3689 case CIPHER_3DES:
3690 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_3des;
3691 break;
3692 case CIPHER_AES:
3693 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_aes;
3694 break;
3695 case CIPHER_WARN:
3696 /* Flag for later. Don't bother if it's the last in
3697 * the list. */
3698 if (i < CIPHER_MAX - 1) {
3699 s->preferred_ciphers[s->n_preferred_ciphers++] = NULL;
3700 }
3701 break;
3702 }
3703 }
3704 }
3705
3706 /*
3707 * Set up preferred compression.
3708 */
3709 if (ssh->cfg.compression)
3710 s->preferred_comp = &ssh_zlib;
3711 else
3712 s->preferred_comp = &ssh_comp_none;
3713
3714 /*
3715 * Be prepared to work around the buggy MAC problem.
3716 */
3717 if (ssh->remote_bugs & BUG_SSH2_HMAC)
3718 s->maclist = buggymacs, s->nmacs = lenof(buggymacs);
3719 else
3720 s->maclist = macs, s->nmacs = lenof(macs);
3721
3722 begin_key_exchange:
3723 {
3724 int i, j, cipherstr_started;
3725
3726 /*
3727 * Construct and send our key exchange packet.
3728 */
3729 ssh2_pkt_init(ssh, SSH2_MSG_KEXINIT);
3730 for (i = 0; i < 16; i++)
3731 ssh2_pkt_addbyte(ssh, (unsigned char) random_byte());
3732 /* List key exchange algorithms. */
3733 ssh2_pkt_addstring_start(ssh);
3734 for (i = 0; i < lenof(kex_algs); i++) {
3735 if (kex_algs[i] == &ssh_diffiehellman_gex &&
3736 (ssh->remote_bugs & BUG_SSH2_DH_GEX))
3737 continue;
3738 ssh2_pkt_addstring_str(ssh, kex_algs[i]->name);
3739 if (i < lenof(kex_algs) - 1)
3740 ssh2_pkt_addstring_str(ssh, ",");
3741 }
3742 /* List server host key algorithms. */
3743 ssh2_pkt_addstring_start(ssh);
3744 for (i = 0; i < lenof(hostkey_algs); i++) {
3745 ssh2_pkt_addstring_str(ssh, hostkey_algs[i]->name);
3746 if (i < lenof(hostkey_algs) - 1)
3747 ssh2_pkt_addstring_str(ssh, ",");
3748 }
3749 /* List client->server encryption algorithms. */
3750 ssh2_pkt_addstring_start(ssh);
3751 cipherstr_started = 0;
3752 for (i = 0; i < s->n_preferred_ciphers; i++) {
3753 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3754 if (!c) continue; /* warning flag */
3755 for (j = 0; j < c->nciphers; j++) {
3756 if (cipherstr_started)
3757 ssh2_pkt_addstring_str(ssh, ",");
3758 ssh2_pkt_addstring_str(ssh, c->list[j]->name);
3759 cipherstr_started = 1;
3760 }
3761 }
3762 /* List server->client encryption algorithms. */
3763 ssh2_pkt_addstring_start(ssh);
3764 cipherstr_started = 0;
3765 for (i = 0; i < s->n_preferred_ciphers; i++) {
3766 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3767 if (!c) continue; /* warning flag */
3768 for (j = 0; j < c->nciphers; j++) {
3769 if (cipherstr_started)
3770 ssh2_pkt_addstring_str(ssh, ",");
3771 ssh2_pkt_addstring_str(ssh, c->list[j]->name);
3772 cipherstr_started = 1;
3773 }
3774 }
3775 /* List client->server MAC algorithms. */
3776 ssh2_pkt_addstring_start(ssh);
3777 for (i = 0; i < s->nmacs; i++) {
3778 ssh2_pkt_addstring_str(ssh, s->maclist[i]->name);
3779 if (i < s->nmacs - 1)
3780 ssh2_pkt_addstring_str(ssh, ",");
3781 }
3782 /* List server->client MAC algorithms. */
3783 ssh2_pkt_addstring_start(ssh);
3784 for (i = 0; i < s->nmacs; i++) {
3785 ssh2_pkt_addstring_str(ssh, s->maclist[i]->name);
3786 if (i < s->nmacs - 1)
3787 ssh2_pkt_addstring_str(ssh, ",");
3788 }
3789 /* List client->server compression algorithms. */
3790 ssh2_pkt_addstring_start(ssh);
3791 for (i = 0; i < lenof(compressions) + 1; i++) {
3792 const struct ssh_compress *c =
3793 i == 0 ? s->preferred_comp : compressions[i - 1];
3794 ssh2_pkt_addstring_str(ssh, c->name);
3795 if (i < lenof(compressions))
3796 ssh2_pkt_addstring_str(ssh, ",");
3797 }
3798 /* List server->client compression algorithms. */
3799 ssh2_pkt_addstring_start(ssh);
3800 for (i = 0; i < lenof(compressions) + 1; i++) {
3801 const struct ssh_compress *c =
3802 i == 0 ? s->preferred_comp : compressions[i - 1];
3803 ssh2_pkt_addstring_str(ssh, c->name);
3804 if (i < lenof(compressions))
3805 ssh2_pkt_addstring_str(ssh, ",");
3806 }
3807 /* List client->server languages. Empty list. */
3808 ssh2_pkt_addstring_start(ssh);
3809 /* List server->client languages. Empty list. */
3810 ssh2_pkt_addstring_start(ssh);
3811 /* First KEX packet does _not_ follow, because we're not that brave. */
3812 ssh2_pkt_addbool(ssh, FALSE);
3813 /* Reserved. */
3814 ssh2_pkt_adduint32(ssh, 0);
3815 }
3816
3817 ssh->exhash = ssh->exhashbase;
3818 sha_string(&ssh->exhash, ssh->pktout.data + 5, ssh->pktout.length - 5);
3819
3820 ssh2_pkt_send(ssh);
3821
3822 if (!ispkt)
3823 crWaitUntil(ispkt);
3824 if (ssh->pktin.length > 5)
3825 sha_string(&ssh->exhash, ssh->pktin.data + 5, ssh->pktin.length - 5);
3826
3827 /*
3828 * Now examine the other side's KEXINIT to see what we're up
3829 * to.
3830 */
3831 {
3832 char *str;
3833 int i, j, len;
3834
3835 if (ssh->pktin.type != SSH2_MSG_KEXINIT) {
3836 bombout((ssh,"expected key exchange packet from server"));
3837 crReturn(0);
3838 }
3839 ssh->kex = NULL;
3840 ssh->hostkey = NULL;
3841 s->cscipher_tobe = NULL;
3842 s->sccipher_tobe = NULL;
3843 s->csmac_tobe = NULL;
3844 s->scmac_tobe = NULL;
3845 s->cscomp_tobe = NULL;
3846 s->sccomp_tobe = NULL;
3847 ssh->pktin.savedpos += 16; /* skip garbage cookie */
3848 ssh2_pkt_getstring(ssh, &str, &len); /* key exchange algorithms */
3849 for (i = 0; i < lenof(kex_algs); i++) {
3850 if (kex_algs[i] == &ssh_diffiehellman_gex &&
3851 (ssh->remote_bugs & BUG_SSH2_DH_GEX))
3852 continue;
3853 if (in_commasep_string(kex_algs[i]->name, str, len)) {
3854 ssh->kex = kex_algs[i];
3855 break;
3856 }
3857 }
3858 ssh2_pkt_getstring(ssh, &str, &len); /* host key algorithms */
3859 for (i = 0; i < lenof(hostkey_algs); i++) {
3860 if (in_commasep_string(hostkey_algs[i]->name, str, len)) {
3861 ssh->hostkey = hostkey_algs[i];
3862 break;
3863 }
3864 }
3865 ssh2_pkt_getstring(ssh, &str, &len); /* client->server cipher */
3866 s->warn = 0;
3867 for (i = 0; i < s->n_preferred_ciphers; i++) {
3868 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3869 if (!c) {
3870 s->warn = 1;
3871 } else {
3872 for (j = 0; j < c->nciphers; j++) {
3873 if (in_commasep_string(c->list[j]->name, str, len)) {
3874 s->cscipher_tobe = c->list[j];
3875 break;
3876 }
3877 }
3878 }
3879 if (s->cscipher_tobe) {
3880 if (s->warn)
3881 askcipher(ssh->frontend, s->cscipher_tobe->name, 1);
3882 break;
3883 }
3884 }
3885 if (!s->cscipher_tobe) {
3886 bombout((ssh,"Couldn't agree a client-to-server cipher (available: %s)",
3887 str ? str : "(null)"));
3888 crReturn(0);
3889 }
3890
3891 ssh2_pkt_getstring(ssh, &str, &len); /* server->client cipher */
3892 s->warn = 0;
3893 for (i = 0; i < s->n_preferred_ciphers; i++) {
3894 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3895 if (!c) {
3896 s->warn = 1;
3897 } else {
3898 for (j = 0; j < c->nciphers; j++) {
3899 if (in_commasep_string(c->list[j]->name, str, len)) {
3900 s->sccipher_tobe = c->list[j];
3901 break;
3902 }
3903 }
3904 }
3905 if (s->sccipher_tobe) {
3906 if (s->warn)
3907 askcipher(ssh->frontend, s->sccipher_tobe->name, 2);
3908 break;
3909 }
3910 }
3911 if (!s->sccipher_tobe) {
3912 bombout((ssh,"Couldn't agree a server-to-client cipher (available: %s)",
3913 str ? str : "(null)"));
3914 crReturn(0);
3915 }
3916
3917 ssh2_pkt_getstring(ssh, &str, &len); /* client->server mac */
3918 for (i = 0; i < s->nmacs; i++) {
3919 if (in_commasep_string(s->maclist[i]->name, str, len)) {
3920 s->csmac_tobe = s->maclist[i];
3921 break;
3922 }
3923 }
3924 ssh2_pkt_getstring(ssh, &str, &len); /* server->client mac */
3925 for (i = 0; i < s->nmacs; i++) {
3926 if (in_commasep_string(s->maclist[i]->name, str, len)) {
3927 s->scmac_tobe = s->maclist[i];
3928 break;
3929 }
3930 }
3931 ssh2_pkt_getstring(ssh, &str, &len); /* client->server compression */
3932 for (i = 0; i < lenof(compressions) + 1; i++) {
3933 const struct ssh_compress *c =
3934 i == 0 ? s->preferred_comp : compressions[i - 1];
3935 if (in_commasep_string(c->name, str, len)) {
3936 s->cscomp_tobe = c;
3937 break;
3938 }
3939 }
3940 ssh2_pkt_getstring(ssh, &str, &len); /* server->client compression */
3941 for (i = 0; i < lenof(compressions) + 1; i++) {
3942 const struct ssh_compress *c =
3943 i == 0 ? s->preferred_comp : compressions[i - 1];
3944 if (in_commasep_string(c->name, str, len)) {
3945 s->sccomp_tobe = c;
3946 break;
3947 }
3948 }
3949 }
3950
3951 /*
3952 * Work out the number of bits of key we will need from the key
3953 * exchange. We start with the maximum key length of either
3954 * cipher...
3955 */
3956 {
3957 int csbits, scbits;
3958
3959 csbits = s->cscipher_tobe->keylen;
3960 scbits = s->sccipher_tobe->keylen;
3961 s->nbits = (csbits > scbits ? csbits : scbits);
3962 }
3963 /* The keys only have 160-bit entropy, since they're based on
3964 * a SHA-1 hash. So cap the key size at 160 bits. */
3965 if (s->nbits > 160)
3966 s->nbits = 160;
3967
3968 /*
3969 * If we're doing Diffie-Hellman group exchange, start by
3970 * requesting a group.
3971 */
3972 if (ssh->kex == &ssh_diffiehellman_gex) {
3973 logevent("Doing Diffie-Hellman group exchange");
3974 ssh->pkt_ctx |= SSH2_PKTCTX_DHGEX;
3975 /*
3976 * Work out how big a DH group we will need to allow that
3977 * much data.
3978 */
3979 s->pbits = 512 << ((s->nbits - 1) / 64);
3980 ssh2_pkt_init(ssh, SSH2_MSG_KEX_DH_GEX_REQUEST);
3981 ssh2_pkt_adduint32(ssh, s->pbits);
3982 ssh2_pkt_send(ssh);
3983
3984 crWaitUntil(ispkt);
3985 if (ssh->pktin.type != SSH2_MSG_KEX_DH_GEX_GROUP) {
3986 bombout((ssh,"expected key exchange group packet from server"));
3987 crReturn(0);
3988 }
3989 s->p = ssh2_pkt_getmp(ssh);
3990 s->g = ssh2_pkt_getmp(ssh);
3991 ssh->kex_ctx = dh_setup_group(s->p, s->g);
3992 s->kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT;
3993 s->kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY;
3994 } else {
3995 ssh->pkt_ctx |= SSH2_PKTCTX_DHGROUP1;
3996 ssh->kex_ctx = dh_setup_group1();
3997 s->kex_init_value = SSH2_MSG_KEXDH_INIT;
3998 s->kex_reply_value = SSH2_MSG_KEXDH_REPLY;
3999 }
4000
4001 logevent("Doing Diffie-Hellman key exchange");
4002 /*
4003 * Now generate and send e for Diffie-Hellman.
4004 */
4005 s->e = dh_create_e(ssh->kex_ctx, s->nbits * 2);
4006 ssh2_pkt_init(ssh, s->kex_init_value);
4007 ssh2_pkt_addmp(ssh, s->e);
4008 ssh2_pkt_send(ssh);
4009
4010 crWaitUntil(ispkt);
4011 if (ssh->pktin.type != s->kex_reply_value) {
4012 bombout((ssh,"expected key exchange reply packet from server"));
4013 crReturn(0);
4014 }
4015 ssh2_pkt_getstring(ssh, &s->hostkeydata, &s->hostkeylen);
4016 s->f = ssh2_pkt_getmp(ssh);
4017 ssh2_pkt_getstring(ssh, &s->sigdata, &s->siglen);
4018
4019 s->K = dh_find_K(ssh->kex_ctx, s->f);
4020
4021 sha_string(&ssh->exhash, s->hostkeydata, s->hostkeylen);
4022 if (ssh->kex == &ssh_diffiehellman_gex) {
4023 sha_uint32(&ssh->exhash, s->pbits);
4024 sha_mpint(&ssh->exhash, s->p);
4025 sha_mpint(&ssh->exhash, s->g);
4026 }
4027 sha_mpint(&ssh->exhash, s->e);
4028 sha_mpint(&ssh->exhash, s->f);
4029 sha_mpint(&ssh->exhash, s->K);
4030 SHA_Final(&ssh->exhash, s->exchange_hash);
4031
4032 dh_cleanup(ssh->kex_ctx);
4033
4034 #if 0
4035 debug(("Exchange hash is:\n"));
4036 dmemdump(s->exchange_hash, 20);
4037 #endif
4038
4039 s->hkey = ssh->hostkey->newkey(s->hostkeydata, s->hostkeylen);
4040 if (!s->hkey ||
4041 !ssh->hostkey->verifysig(s->hkey, s->sigdata, s->siglen,
4042 (char *)s->exchange_hash, 20)) {
4043 bombout((ssh,"Server's host key did not match the signature supplied"));
4044 crReturn(0);
4045 }
4046
4047 /*
4048 * Authenticate remote host: verify host key. (We've already
4049 * checked the signature of the exchange hash.)
4050 */
4051 s->keystr = ssh->hostkey->fmtkey(s->hkey);
4052 s->fingerprint = ssh->hostkey->fingerprint(s->hkey);
4053 verify_ssh_host_key(ssh->frontend,
4054 ssh->savedhost, ssh->savedport, ssh->hostkey->keytype,
4055 s->keystr, s->fingerprint);
4056 if (s->first_kex) { /* don't bother logging this in rekeys */
4057 logevent("Host key fingerprint is:");
4058 logevent(s->fingerprint);
4059 }
4060 sfree(s->fingerprint);
4061 sfree(s->keystr);
4062 ssh->hostkey->freekey(s->hkey);
4063
4064 /*
4065 * Send SSH2_MSG_NEWKEYS.
4066 */
4067 ssh2_pkt_init(ssh, SSH2_MSG_NEWKEYS);
4068 ssh2_pkt_send(ssh);
4069
4070 /*
4071 * Expect SSH2_MSG_NEWKEYS from server.
4072 */
4073 crWaitUntil(ispkt);
4074 if (ssh->pktin.type != SSH2_MSG_NEWKEYS) {
4075 bombout((ssh,"expected new-keys packet from server"));
4076 crReturn(0);
4077 }
4078
4079 /*
4080 * Create and initialise session keys.
4081 */
4082 if (ssh->cs_cipher_ctx)
4083 ssh->cscipher->free_context(ssh->cs_cipher_ctx);
4084 ssh->cscipher = s->cscipher_tobe;
4085 ssh->cs_cipher_ctx = ssh->cscipher->make_context();
4086
4087 if (ssh->sc_cipher_ctx)
4088 ssh->sccipher->free_context(ssh->sc_cipher_ctx);
4089 ssh->sccipher = s->sccipher_tobe;
4090 ssh->sc_cipher_ctx = ssh->sccipher->make_context();
4091
4092 if (ssh->cs_mac_ctx)
4093 ssh->csmac->free_context(ssh->cs_mac_ctx);
4094 ssh->csmac = s->csmac_tobe;
4095 ssh->cs_mac_ctx = ssh->csmac->make_context();
4096
4097 if (ssh->sc_mac_ctx)
4098 ssh->scmac->free_context(ssh->sc_mac_ctx);
4099 ssh->scmac = s->scmac_tobe;
4100 ssh->sc_mac_ctx = ssh->scmac->make_context();
4101
4102 if (ssh->cs_comp_ctx)
4103 ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
4104 ssh->cscomp = s->cscomp_tobe;
4105 ssh->cs_comp_ctx = ssh->cscomp->compress_init();
4106
4107 if (ssh->sc_comp_ctx)
4108 ssh->sccomp->decompress_cleanup(ssh->sc_comp_ctx);
4109 ssh->sccomp = s->sccomp_tobe;
4110 ssh->sc_comp_ctx = ssh->sccomp->decompress_init();
4111
4112 /*
4113 * Set IVs after keys. Here we use the exchange hash from the
4114 * _first_ key exchange.
4115 */
4116 {
4117 unsigned char keyspace[40];
4118 if (s->first_kex)
4119 memcpy(ssh->v2_session_id, s->exchange_hash,
4120 sizeof(s->exchange_hash));
4121 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'C',keyspace);
4122 ssh->cscipher->setkey(ssh->cs_cipher_ctx, keyspace);
4123 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'D',keyspace);
4124 ssh->sccipher->setkey(ssh->sc_cipher_ctx, keyspace);
4125 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'A',keyspace);
4126 ssh->cscipher->setiv(ssh->cs_cipher_ctx, keyspace);
4127 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'B',keyspace);
4128 ssh->sccipher->setiv(ssh->sc_cipher_ctx, keyspace);
4129 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'E',keyspace);
4130 ssh->csmac->setkey(ssh->cs_mac_ctx, keyspace);
4131 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'F',keyspace);
4132 ssh->scmac->setkey(ssh->sc_mac_ctx, keyspace);
4133 }
4134 logeventf(ssh, "Initialised %.200s client->server encryption",
4135 ssh->cscipher->text_name);
4136 logeventf(ssh, "Initialised %.200s server->client encryption",
4137 ssh->sccipher->text_name);
4138 if (ssh->cscomp->text_name)
4139 logeventf(ssh, "Initialised %s compression",
4140 ssh->cscomp->text_name);
4141 if (ssh->sccomp->text_name)
4142 logeventf(ssh, "Initialised %s decompression",
4143 ssh->sccomp->text_name);
4144
4145 /*
4146 * If this is the first key exchange phase, we must pass the
4147 * SSH2_MSG_NEWKEYS packet to the next layer, not because it
4148 * wants to see it but because it will need time to initialise
4149 * itself before it sees an actual packet. In subsequent key
4150 * exchange phases, we don't pass SSH2_MSG_NEWKEYS on, because
4151 * it would only confuse the layer above.
4152 */
4153 if (!s->first_kex) {
4154 crReturn(0);
4155 }
4156 s->first_kex = 0;
4157
4158 /*
4159 * Now we're encrypting. Begin returning 1 to the protocol main
4160 * function so that other things can run on top of the
4161 * transport. If we ever see a KEXINIT, we must go back to the
4162 * start.
4163 */
4164 while (!(ispkt && ssh->pktin.type == SSH2_MSG_KEXINIT)) {
4165 crReturn(1);
4166 }
4167 logevent("Server initiated key re-exchange");
4168 goto begin_key_exchange;
4169
4170 crFinish(1);
4171 }
4172
4173 /*
4174 * Add data to an SSH2 channel output buffer.
4175 */
4176 static void ssh2_add_channel_data(struct ssh_channel *c, char *buf,
4177 int len)
4178 {
4179 bufchain_add(&c->v.v2.outbuffer, buf, len);
4180 }
4181
4182 /*
4183 * Attempt to send data on an SSH2 channel.
4184 */
4185 static int ssh2_try_send(struct ssh_channel *c)
4186 {
4187 Ssh ssh = c->ssh;
4188
4189 while (c->v.v2.remwindow > 0 && bufchain_size(&c->v.v2.outbuffer) > 0) {
4190 int len;
4191 void *data;
4192 bufchain_prefix(&c->v.v2.outbuffer, &data, &len);
4193 if ((unsigned)len > c->v.v2.remwindow)
4194 len = c->v.v2.remwindow;
4195 if ((unsigned)len > c->v.v2.remmaxpkt)
4196 len = c->v.v2.remmaxpkt;
4197 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_DATA);
4198 ssh2_pkt_adduint32(ssh, c->remoteid);
4199 ssh2_pkt_addstring_start(ssh);
4200 ssh2_pkt_addstring_data(ssh, data, len);
4201 ssh2_pkt_send(ssh);
4202 bufchain_consume(&c->v.v2.outbuffer, len);
4203 c->v.v2.remwindow -= len;
4204 }
4205
4206 /*
4207 * After having sent as much data as we can, return the amount
4208 * still buffered.
4209 */
4210 return bufchain_size(&c->v.v2.outbuffer);
4211 }
4212
4213 /*
4214 * Potentially enlarge the window on an SSH2 channel.
4215 */
4216 static void ssh2_set_window(struct ssh_channel *c, unsigned newwin)
4217 {
4218 Ssh ssh = c->ssh;
4219
4220 /*
4221 * Never send WINDOW_ADJUST for a channel that the remote side
4222 * already thinks it's closed; there's no point, since it won't
4223 * be sending any more data anyway.
4224 */
4225 if (c->closes != 0)
4226 return;
4227
4228 if (newwin > c->v.v2.locwindow) {
4229 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST);
4230 ssh2_pkt_adduint32(ssh, c->remoteid);
4231 ssh2_pkt_adduint32(ssh, newwin - c->v.v2.locwindow);
4232 ssh2_pkt_send(ssh);
4233 c->v.v2.locwindow = newwin;
4234 }
4235 }
4236
4237 /*
4238 * Handle the SSH2 userauth and connection layers.
4239 */
4240 static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
4241 {
4242 struct do_ssh2_authconn_state {
4243 enum {
4244 AUTH_INVALID, AUTH_PUBLICKEY_AGENT, AUTH_PUBLICKEY_FILE,
4245 AUTH_PASSWORD,
4246 AUTH_KEYBOARD_INTERACTIVE
4247 } method;
4248 enum {
4249 AUTH_TYPE_NONE,
4250 AUTH_TYPE_PUBLICKEY,
4251 AUTH_TYPE_PUBLICKEY_OFFER_LOUD,
4252 AUTH_TYPE_PUBLICKEY_OFFER_QUIET,
4253 AUTH_TYPE_PASSWORD,
4254 AUTH_TYPE_KEYBOARD_INTERACTIVE,
4255 AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET
4256 } type;
4257 int gotit, need_pw, can_pubkey, can_passwd, can_keyb_inter;
4258 int tried_pubkey_config, tried_agent, tried_keyb_inter;
4259 int kbd_inter_running;
4260 int we_are_in;
4261 int num_prompts, curr_prompt, echo;
4262 char username[100];
4263 int got_username;
4264 char pwprompt[200];
4265 char password[100];
4266 void *publickey_blob;
4267 int publickey_bloblen;
4268 unsigned char request[5], *response, *p;
4269 int responselen;
4270 int keyi, nkeys;
4271 int authed;
4272 char *pkblob, *alg, *commentp;
4273 int pklen, alglen, commentlen;
4274 int siglen, retlen, len;
4275 char *q, *agentreq, *ret;
4276 int try_send;
4277 };
4278 crState(do_ssh2_authconn_state);
4279
4280 crBegin(ssh->do_ssh2_authconn_crstate);
4281
4282 /*
4283 * Request userauth protocol, and await a response to it.
4284 */
4285 ssh2_pkt_init(ssh, SSH2_MSG_SERVICE_REQUEST);
4286 ssh2_pkt_addstring(ssh, "ssh-userauth");
4287 ssh2_pkt_send(ssh);
4288 crWaitUntilV(ispkt);
4289 if (ssh->pktin.type != SSH2_MSG_SERVICE_ACCEPT) {
4290 bombout((ssh,"Server refused user authentication protocol"));
4291 crReturnV;
4292 }
4293
4294 /*
4295 * We repeat this whole loop, including the username prompt,
4296 * until we manage a successful authentication. If the user
4297 * types the wrong _password_, they can be sent back to the
4298 * beginning to try another username, if this is configured on.
4299 * (If they specify a username in the config, they are never
4300 * asked, even if they do give a wrong password.)
4301 *
4302 * I think this best serves the needs of
4303 *
4304 * - the people who have no configuration, no keys, and just
4305 * want to try repeated (username,password) pairs until they
4306 * type both correctly
4307 *
4308 * - people who have keys and configuration but occasionally
4309 * need to fall back to passwords
4310 *
4311 * - people with a key held in Pageant, who might not have
4312 * logged in to a particular machine before; so they want to
4313 * type a username, and then _either_ their key will be
4314 * accepted, _or_ they will type a password. If they mistype
4315 * the username they will want to be able to get back and
4316 * retype it!
4317 */
4318 s->username[0] = '\0';
4319 s->got_username = FALSE;
4320 do {
4321 /*
4322 * Get a username.
4323 */
4324 if (s->got_username && !ssh->cfg.change_username) {
4325 /*
4326 * We got a username last time round this loop, and
4327 * with change_username turned off we don't try to get
4328 * it again.
4329 */
4330 } else if ((flags & FLAG_INTERACTIVE) && !*ssh->cfg.username) {
4331 if (ssh_get_line && !ssh_getline_pw_only) {
4332 if (!ssh_get_line("login as: ",
4333 s->username, sizeof(s->username), FALSE)) {
4334 /*
4335 * get_line failed to get a username.
4336 * Terminate.
4337 */
4338 logevent("No username provided. Abandoning session.");
4339 ssh->state = SSH_STATE_CLOSED;
4340 crReturnV;
4341 }
4342 } else {
4343 int ret; /* need not be saved across crReturn */
4344 c_write_str(ssh, "login as: ");
4345 ssh->send_ok = 1;
4346 setup_userpass_input(ssh, s->username, sizeof(s->username), 1);
4347 do {
4348 crWaitUntilV(!ispkt);
4349 ret = process_userpass_input(ssh, in, inlen);
4350 } while (ret == 0);
4351 if (ret < 0)
4352 cleanup_exit(0);
4353 c_write_str(ssh, "\r\n");
4354 }
4355 s->username[strcspn(s->username, "\n\r")] = '\0';
4356 } else {
4357 char *stuff;
4358 strncpy(s->username, ssh->cfg.username, sizeof(s->username));
4359 s->username[sizeof(s->username)-1] = '\0';
4360 if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
4361 stuff = dupprintf("Using username \"%s\".\r\n", s->username);
4362 c_write_str(ssh, stuff);
4363 sfree(stuff);
4364 }
4365 }
4366 s->got_username = TRUE;
4367
4368 /*
4369 * Send an authentication request using method "none": (a)
4370 * just in case it succeeds, and (b) so that we know what
4371 * authentication methods we can usefully try next.
4372 */
4373 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4374
4375 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4376 ssh2_pkt_addstring(ssh, s->username);
4377 ssh2_pkt_addstring(ssh, "ssh-connection");/* service requested */
4378 ssh2_pkt_addstring(ssh, "none"); /* method */
4379 ssh2_pkt_send(ssh);
4380 s->type = AUTH_TYPE_NONE;
4381 s->gotit = FALSE;
4382 s->we_are_in = FALSE;
4383
4384 s->tried_pubkey_config = FALSE;
4385 s->tried_agent = FALSE;
4386 s->tried_keyb_inter = FALSE;
4387 s->kbd_inter_running = FALSE;
4388 /* Load the pub half of ssh->cfg.keyfile so we notice if it's in Pageant */
4389 if (*ssh->cfg.keyfile) {
4390 int keytype;
4391 logeventf(ssh, "Reading private key file \"%.150s\"", ssh->cfg.keyfile);
4392 keytype = key_type(ssh->cfg.keyfile);
4393 if (keytype == SSH_KEYTYPE_SSH2) {
4394 s->publickey_blob =
4395 ssh2_userkey_loadpub(ssh->cfg.keyfile, NULL,
4396 &s->publickey_bloblen);
4397 } else {
4398 char *msgbuf;
4399 logeventf(ssh, "Unable to use this key file (%s)",
4400 key_type_to_str(keytype));
4401 msgbuf = dupprintf("Unable to use key file \"%.150s\""
4402 " (%s)\r\n", ssh->cfg.keyfile,
4403 key_type_to_str(keytype));
4404 c_write_str(ssh, msgbuf);
4405 sfree(msgbuf);
4406 s->publickey_blob = NULL;
4407 }
4408 } else
4409 s->publickey_blob = NULL;
4410
4411 while (1) {
4412 /*
4413 * Wait for the result of the last authentication request.
4414 */
4415 if (!s->gotit)
4416 crWaitUntilV(ispkt);
4417 while (ssh->pktin.type == SSH2_MSG_USERAUTH_BANNER) {
4418 char *banner;
4419 int size;
4420 /*
4421 * Don't show the banner if we're operating in
4422 * non-verbose non-interactive mode. (It's probably
4423 * a script, which means nobody will read the
4424 * banner _anyway_, and moreover the printing of
4425 * the banner will screw up processing on the
4426 * output of (say) plink.)
4427 */
4428 if (flags & (FLAG_VERBOSE | FLAG_INTERACTIVE)) {
4429 ssh2_pkt_getstring(ssh, &banner, &size);
4430 if (banner)
4431 c_write_untrusted(ssh, banner, size);
4432 }
4433 crWaitUntilV(ispkt);
4434 }
4435 if (ssh->pktin.type == SSH2_MSG_USERAUTH_SUCCESS) {
4436 logevent("Access granted");
4437 s->we_are_in = TRUE;
4438 break;
4439 }
4440
4441 if (s->kbd_inter_running &&
4442 ssh->pktin.type == SSH2_MSG_USERAUTH_INFO_REQUEST) {
4443 /*
4444 * This is either a further set-of-prompts packet
4445 * in keyboard-interactive authentication, or it's
4446 * the same one and we came back here with `gotit'
4447 * set. In the former case, we must reset the
4448 * curr_prompt variable.
4449 */
4450 if (!s->gotit)
4451 s->curr_prompt = 0;
4452 } else if (ssh->pktin.type != SSH2_MSG_USERAUTH_FAILURE) {
4453 bombout((ssh,"Strange packet received during authentication: type %d",
4454 ssh->pktin.type));
4455 crReturnV;
4456 }
4457
4458 s->gotit = FALSE;
4459
4460 /*
4461 * OK, we're now sitting on a USERAUTH_FAILURE message, so
4462 * we can look at the string in it and know what we can
4463 * helpfully try next.
4464 */
4465 if (ssh->pktin.type == SSH2_MSG_USERAUTH_FAILURE) {
4466 char *methods;
4467 int methlen;
4468 ssh2_pkt_getstring(ssh, &methods, &methlen);
4469 s->kbd_inter_running = FALSE;
4470 if (!ssh2_pkt_getbool(ssh)) {
4471 /*
4472 * We have received an unequivocal Access
4473 * Denied. This can translate to a variety of
4474 * messages:
4475 *
4476 * - if we'd just tried "none" authentication,
4477 * it's not worth printing anything at all
4478 *
4479 * - if we'd just tried a public key _offer_,
4480 * the message should be "Server refused our
4481 * key" (or no message at all if the key
4482 * came from Pageant)
4483 *
4484 * - if we'd just tried anything else, the
4485 * message really should be "Access denied".
4486 *
4487 * Additionally, if we'd just tried password
4488 * authentication, we should break out of this
4489 * whole loop so as to go back to the username
4490 * prompt.
4491 */
4492 if (s->type == AUTH_TYPE_NONE) {
4493 /* do nothing */
4494 } else if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD ||
4495 s->type == AUTH_TYPE_PUBLICKEY_OFFER_QUIET) {
4496 if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD)
4497 c_write_str(ssh, "Server refused our key\r\n");
4498 logevent("Server refused public key");
4499 } else if (s->type==AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET) {
4500 /* server declined keyboard-interactive; ignore */
4501 } else {
4502 c_write_str(ssh, "Access denied\r\n");
4503 logevent("Access denied");
4504 if (s->type == AUTH_TYPE_PASSWORD) {
4505 s->we_are_in = FALSE;
4506 break;
4507 }
4508 }
4509 } else {
4510 c_write_str(ssh, "Further authentication required\r\n");
4511 logevent("Further authentication required");
4512 }
4513
4514 s->can_pubkey =
4515 in_commasep_string("publickey", methods, methlen);
4516 s->can_passwd =
4517 in_commasep_string("password", methods, methlen);
4518 s->can_keyb_inter = ssh->cfg.try_ki_auth &&
4519 in_commasep_string("keyboard-interactive", methods, methlen);
4520 }
4521
4522 s->method = 0;
4523 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4524
4525 /*
4526 * Most password/passphrase prompts will be
4527 * non-echoing, so we set this to 0 by default.
4528 * Exception is that some keyboard-interactive prompts
4529 * can be echoing, in which case we'll set this to 1.
4530 */
4531 s->echo = 0;
4532
4533 if (!s->method && s->can_pubkey &&
4534 agent_exists() && !s->tried_agent) {
4535 /*
4536 * Attempt public-key authentication using Pageant.
4537 */
4538 void *r;
4539 s->authed = FALSE;
4540
4541 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4542 ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
4543
4544 s->tried_agent = TRUE;
4545
4546 logevent("Pageant is running. Requesting keys.");
4547
4548 /* Request the keys held by the agent. */
4549 PUT_32BIT(s->request, 1);
4550 s->request[4] = SSH2_AGENTC_REQUEST_IDENTITIES;
4551 agent_query(s->request, 5, &r, &s->responselen);
4552 s->response = (unsigned char *) r;
4553 if (s->response && s->responselen >= 5 &&
4554 s->response[4] == SSH2_AGENT_IDENTITIES_ANSWER) {
4555 s->p = s->response + 5;
4556 s->nkeys = GET_32BIT(s->p);
4557 s->p += 4;
4558 {
4559 char buf[64];
4560 sprintf(buf, "Pageant has %d SSH2 keys", s->nkeys);
4561 logevent(buf);
4562 }
4563 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
4564 void *vret;
4565
4566 {
4567 char buf[64];
4568 sprintf(buf, "Trying Pageant key #%d", s->keyi);
4569 logevent(buf);
4570 }
4571 s->pklen = GET_32BIT(s->p);
4572 s->p += 4;
4573 if (s->publickey_blob &&
4574 s->pklen == s->publickey_bloblen &&
4575 !memcmp(s->p, s->publickey_blob,
4576 s->publickey_bloblen)) {
4577 logevent("This key matches configured key file");
4578 s->tried_pubkey_config = 1;
4579 }
4580 s->pkblob = (char *)s->p;
4581 s->p += s->pklen;
4582 s->alglen = GET_32BIT(s->pkblob);
4583 s->alg = s->pkblob + 4;
4584 s->commentlen = GET_32BIT(s->p);
4585 s->p += 4;
4586 s->commentp = (char *)s->p;
4587 s->p += s->commentlen;
4588 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4589 ssh2_pkt_addstring(ssh, s->username);
4590 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4591 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4592 ssh2_pkt_addbool(ssh, FALSE); /* no signature included */
4593 ssh2_pkt_addstring_start(ssh);
4594 ssh2_pkt_addstring_data(ssh, s->alg, s->alglen);
4595 ssh2_pkt_addstring_start(ssh);
4596 ssh2_pkt_addstring_data(ssh, s->pkblob, s->pklen);
4597 ssh2_pkt_send(ssh);
4598
4599 crWaitUntilV(ispkt);
4600 if (ssh->pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
4601 logevent("Key refused");
4602 continue;
4603 }
4604
4605 if (flags & FLAG_VERBOSE) {
4606 c_write_str(ssh, "Authenticating with "
4607 "public key \"");
4608 c_write(ssh, s->commentp, s->commentlen);
4609 c_write_str(ssh, "\" from agent\r\n");
4610 }
4611
4612 /*
4613 * Server is willing to accept the key.
4614 * Construct a SIGN_REQUEST.
4615 */
4616 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4617 ssh2_pkt_addstring(ssh, s->username);
4618 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4619 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4620 ssh2_pkt_addbool(ssh, TRUE);
4621 ssh2_pkt_addstring_start(ssh);
4622 ssh2_pkt_addstring_data(ssh, s->alg, s->alglen);
4623 ssh2_pkt_addstring_start(ssh);
4624 ssh2_pkt_addstring_data(ssh, s->pkblob, s->pklen);
4625
4626 s->siglen = ssh->pktout.length - 5 + 4 + 20;
4627 s->len = 1; /* message type */
4628 s->len += 4 + s->pklen; /* key blob */
4629 s->len += 4 + s->siglen; /* data to sign */
4630 s->len += 4; /* flags */
4631 s->agentreq = smalloc(4 + s->len);
4632 PUT_32BIT(s->agentreq, s->len);
4633 s->q = s->agentreq + 4;
4634 *s->q++ = SSH2_AGENTC_SIGN_REQUEST;
4635 PUT_32BIT(s->q, s->pklen);
4636 s->q += 4;
4637 memcpy(s->q, s->pkblob, s->pklen);
4638 s->q += s->pklen;
4639 PUT_32BIT(s->q, s->siglen);
4640 s->q += 4;
4641 /* Now the data to be signed... */
4642 PUT_32BIT(s->q, 20);
4643 s->q += 4;
4644 memcpy(s->q, ssh->v2_session_id, 20);
4645 s->q += 20;
4646 memcpy(s->q, ssh->pktout.data + 5,
4647 ssh->pktout.length - 5);
4648 s->q += ssh->pktout.length - 5;
4649 /* And finally the (zero) flags word. */
4650 PUT_32BIT(s->q, 0);
4651 agent_query(s->agentreq, s->len + 4, &vret, &s->retlen);
4652 s->ret = vret;
4653 sfree(s->agentreq);
4654 if (s->ret) {
4655 if (s->ret[4] == SSH2_AGENT_SIGN_RESPONSE) {
4656 logevent("Sending Pageant's response");
4657 ssh2_add_sigblob(ssh, s->pkblob, s->pklen,
4658 s->ret + 9,
4659 GET_32BIT(s->ret + 5));
4660 ssh2_pkt_send(ssh);
4661 s->authed = TRUE;
4662 break;
4663 } else {
4664 logevent
4665 ("Pageant failed to answer challenge");
4666 sfree(s->ret);
4667 }
4668 }
4669 }
4670 if (s->authed)
4671 continue;
4672 }
4673 }
4674
4675 if (!s->method && s->can_pubkey && s->publickey_blob
4676 && !s->tried_pubkey_config) {
4677 unsigned char *pub_blob;
4678 char *algorithm, *comment;
4679 int pub_blob_len;
4680
4681 s->tried_pubkey_config = TRUE;
4682
4683 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4684 ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
4685
4686 /*
4687 * Try the public key supplied in the configuration.
4688 *
4689 * First, offer the public blob to see if the server is
4690 * willing to accept it.
4691 */
4692 pub_blob =
4693 (unsigned char *)ssh2_userkey_loadpub(ssh->cfg.keyfile,
4694 &algorithm,
4695 &pub_blob_len);
4696 if (pub_blob) {
4697 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4698 ssh2_pkt_addstring(ssh, s->username);
4699 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4700 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4701 ssh2_pkt_addbool(ssh, FALSE); /* no signature included */
4702 ssh2_pkt_addstring(ssh, algorithm);
4703 ssh2_pkt_addstring_start(ssh);
4704 ssh2_pkt_addstring_data(ssh, (char *)pub_blob,
4705 pub_blob_len);
4706 ssh2_pkt_send(ssh);
4707 logevent("Offered public key"); /* FIXME */
4708
4709 crWaitUntilV(ispkt);
4710 if (ssh->pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
4711 s->gotit = TRUE;
4712 s->type = AUTH_TYPE_PUBLICKEY_OFFER_LOUD;
4713 continue; /* key refused; give up on it */
4714 }
4715
4716 logevent("Offer of public key accepted");
4717 /*
4718 * Actually attempt a serious authentication using
4719 * the key.
4720 */
4721 if (ssh2_userkey_encrypted(ssh->cfg.keyfile, &comment)) {
4722 sprintf(s->pwprompt,
4723 "Passphrase for key \"%.100s\": ",
4724 comment);
4725 s->need_pw = TRUE;
4726 } else {
4727 s->need_pw = FALSE;
4728 }
4729 c_write_str(ssh, "Authenticating with public key \"");
4730 c_write_str(ssh, comment);
4731 c_write_str(ssh, "\"\r\n");
4732 s->method = AUTH_PUBLICKEY_FILE;
4733 }
4734 }
4735
4736 if (!s->method && s->can_keyb_inter && !s->tried_keyb_inter) {
4737 s->method = AUTH_KEYBOARD_INTERACTIVE;
4738 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
4739 s->tried_keyb_inter = TRUE;
4740
4741 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4742 ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;
4743
4744 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4745 ssh2_pkt_addstring(ssh, s->username);
4746 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4747 ssh2_pkt_addstring(ssh, "keyboard-interactive"); /* method */
4748 ssh2_pkt_addstring(ssh, ""); /* lang */
4749 ssh2_pkt_addstring(ssh, "");
4750 ssh2_pkt_send(ssh);
4751
4752 crWaitUntilV(ispkt);
4753 if (ssh->pktin.type != SSH2_MSG_USERAUTH_INFO_REQUEST) {
4754 if (ssh->pktin.type == SSH2_MSG_USERAUTH_FAILURE)
4755 s->gotit = TRUE;
4756 logevent("Keyboard-interactive authentication refused");
4757 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET;
4758 continue;
4759 }
4760
4761 s->kbd_inter_running = TRUE;
4762 s->curr_prompt = 0;
4763 }
4764
4765 if (s->kbd_inter_running) {
4766 s->method = AUTH_KEYBOARD_INTERACTIVE;
4767 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
4768 s->tried_keyb_inter = TRUE;
4769
4770 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4771 ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;
4772
4773 if (s->curr_prompt == 0) {
4774 /*
4775 * We've got a fresh USERAUTH_INFO_REQUEST.
4776 * Display header data, and start going through
4777 * the prompts.
4778 */
4779 char *name, *inst, *lang;
4780 int name_len, inst_len, lang_len;
4781
4782 ssh2_pkt_getstring(ssh, &name, &name_len);
4783 ssh2_pkt_getstring(ssh, &inst, &inst_len);
4784 ssh2_pkt_getstring(ssh, &lang, &lang_len);
4785 if (name_len > 0) {
4786 c_write_untrusted(ssh, name, name_len);
4787 c_write_str(ssh, "\r\n");
4788 }
4789 if (inst_len > 0) {
4790 c_write_untrusted(ssh, inst, inst_len);
4791 c_write_str(ssh, "\r\n");
4792 }
4793 s->num_prompts = ssh2_pkt_getuint32(ssh);
4794 }
4795
4796 /*
4797 * If there are prompts remaining in the packet,
4798 * display one and get a response.
4799 */
4800 if (s->curr_prompt < s->num_prompts) {
4801 char *prompt;
4802 int prompt_len;
4803
4804 ssh2_pkt_getstring(ssh, &prompt, &prompt_len);
4805 if (prompt_len > 0) {
4806 strncpy(s->pwprompt, prompt, sizeof(s->pwprompt));
4807 s->pwprompt[prompt_len < sizeof(s->pwprompt) ?
4808 prompt_len : sizeof(s->pwprompt)-1] = '\0';
4809 } else {
4810 strcpy(s->pwprompt,
4811 "<server failed to send prompt>: ");
4812 }
4813 s->echo = ssh2_pkt_getbool(ssh);
4814 s->need_pw = TRUE;
4815 } else
4816 s->need_pw = FALSE;
4817 }
4818
4819 if (!s->method && s->can_passwd) {
4820 s->method = AUTH_PASSWORD;
4821 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4822 ssh->pkt_ctx |= SSH2_PKTCTX_PASSWORD;
4823 sprintf(s->pwprompt, "%.90s@%.90s's password: ", s->username,
4824 ssh->savedhost);
4825 s->need_pw = TRUE;
4826 }
4827
4828 if (s->need_pw) {
4829 if (ssh_get_line) {
4830 if (!ssh_get_line(s->pwprompt, s->password,
4831 sizeof(s->password), TRUE)) {
4832 /*
4833 * get_line failed to get a password (for
4834 * example because one was supplied on the
4835 * command line which has already failed to
4836 * work). Terminate.
4837 */
4838 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
4839 ssh2_pkt_adduint32(ssh,SSH2_DISCONNECT_BY_APPLICATION);
4840 ssh2_pkt_addstring(ssh, "No more passwords available"
4841 " to try");
4842 ssh2_pkt_addstring(ssh, "en"); /* language tag */
4843 ssh2_pkt_send(ssh);
4844 logevent("Unable to authenticate");
4845 connection_fatal(ssh->frontend,
4846 "Unable to authenticate");
4847 ssh->state = SSH_STATE_CLOSED;
4848 crReturnV;
4849 }
4850 } else {
4851 int ret; /* need not be saved across crReturn */
4852 c_write_untrusted(ssh, s->pwprompt, strlen(s->pwprompt));
4853 ssh->send_ok = 1;
4854
4855 setup_userpass_input(ssh, s->password,
4856 sizeof(s->password), s->echo);
4857 do {
4858 crWaitUntilV(!ispkt);
4859 ret = process_userpass_input(ssh, in, inlen);
4860 } while (ret == 0);
4861 if (ret < 0)
4862 cleanup_exit(0);
4863 c_write_str(ssh, "\r\n");
4864 }
4865 }
4866
4867 if (s->method == AUTH_PUBLICKEY_FILE) {
4868 /*
4869 * We have our passphrase. Now try the actual authentication.
4870 */
4871 struct ssh2_userkey *key;
4872
4873 key = ssh2_load_userkey(ssh->cfg.keyfile, s->password);
4874 if (key == SSH2_WRONG_PASSPHRASE || key == NULL) {
4875 if (key == SSH2_WRONG_PASSPHRASE) {
4876 c_write_str(ssh, "Wrong passphrase\r\n");
4877 s->tried_pubkey_config = FALSE;
4878 } else {
4879 c_write_str(ssh, "Unable to load private key\r\n");
4880 s->tried_pubkey_config = TRUE;
4881 }
4882 /* Send a spurious AUTH_NONE to return to the top. */
4883 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4884 ssh2_pkt_addstring(ssh, s->username);
4885 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4886 ssh2_pkt_addstring(ssh, "none"); /* method */
4887 ssh2_pkt_send(ssh);
4888 s->type = AUTH_TYPE_NONE;
4889 } else {
4890 unsigned char *pkblob, *sigblob, *sigdata;
4891 int pkblob_len, sigblob_len, sigdata_len;
4892
4893 /*
4894 * We have loaded the private key and the server
4895 * has announced that it's willing to accept it.
4896 * Hallelujah. Generate a signature and send it.
4897 */
4898 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4899 ssh2_pkt_addstring(ssh, s->username);
4900 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4901 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4902 ssh2_pkt_addbool(ssh, TRUE);
4903 ssh2_pkt_addstring(ssh, key->alg->name);
4904 pkblob = key->alg->public_blob(key->data, &pkblob_len);
4905 ssh2_pkt_addstring_start(ssh);
4906 ssh2_pkt_addstring_data(ssh, (char *)pkblob, pkblob_len);
4907
4908 /*
4909 * The data to be signed is:
4910 *
4911 * string session-id
4912 *
4913 * followed by everything so far placed in the
4914 * outgoing packet.
4915 */
4916 sigdata_len = ssh->pktout.length - 5 + 4 + 20;
4917 sigdata = smalloc(sigdata_len);
4918 PUT_32BIT(sigdata, 20);
4919 memcpy(sigdata + 4, ssh->v2_session_id, 20);
4920 memcpy(sigdata + 24, ssh->pktout.data + 5,
4921 ssh->pktout.length - 5);
4922 sigblob = key->alg->sign(key->data, (char *)sigdata,
4923 sigdata_len, &sigblob_len);
4924 ssh2_add_sigblob(ssh, pkblob, pkblob_len,
4925 sigblob, sigblob_len);
4926 sfree(pkblob);
4927 sfree(sigblob);
4928 sfree(sigdata);
4929
4930 ssh2_pkt_send(ssh);
4931 s->type = AUTH_TYPE_PUBLICKEY;
4932 }
4933 } else if (s->method == AUTH_PASSWORD) {
4934 /*
4935 * We send the password packet lumped tightly together with
4936 * an SSH_MSG_IGNORE packet. The IGNORE packet contains a
4937 * string long enough to make the total length of the two
4938 * packets constant. This should ensure that a passive
4939 * listener doing traffic analyis can't work out the length
4940 * of the password.
4941 *
4942 * For this to work, we need an assumption about the
4943 * maximum length of the password packet. I think 256 is
4944 * pretty conservative. Anyone using a password longer than
4945 * that probably doesn't have much to worry about from
4946 * people who find out how long their password is!
4947 */
4948 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4949 ssh2_pkt_addstring(ssh, s->username);
4950 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4951 ssh2_pkt_addstring(ssh, "password");
4952 ssh2_pkt_addbool(ssh, FALSE);
4953 ssh2_pkt_addstring(ssh, s->password);
4954 memset(s->password, 0, sizeof(s->password));
4955 ssh2_pkt_defer(ssh);
4956 /*
4957 * We'll include a string that's an exact multiple of the
4958 * cipher block size. If the cipher is NULL for some
4959 * reason, we don't do this trick at all because we gain
4960 * nothing by it.
4961 */
4962 if (ssh->cscipher) {
4963 int stringlen, i;
4964
4965 stringlen = (256 - ssh->deferred_len);
4966 stringlen += ssh->cscipher->blksize - 1;
4967 stringlen -= (stringlen % ssh->cscipher->blksize);
4968 if (ssh->cscomp) {
4969 /*
4970 * Temporarily disable actual compression,
4971 * so we can guarantee to get this string
4972 * exactly the length we want it. The
4973 * compression-disabling routine should
4974 * return an integer indicating how many
4975 * bytes we should adjust our string length
4976 * by.
4977 */
4978 stringlen -=
4979 ssh->cscomp->disable_compression(ssh->cs_comp_ctx);
4980 }
4981 ssh2_pkt_init(ssh, SSH2_MSG_IGNORE);
4982 ssh2_pkt_addstring_start(ssh);
4983 for (i = 0; i < stringlen; i++) {
4984 char c = (char) random_byte();
4985 ssh2_pkt_addstring_data(ssh, &c, 1);
4986 }
4987 ssh2_pkt_defer(ssh);
4988 }
4989 ssh_pkt_defersend(ssh);
4990 logevent("Sent password");
4991 s->type = AUTH_TYPE_PASSWORD;
4992 } else if (s->method == AUTH_KEYBOARD_INTERACTIVE) {
4993 if (s->curr_prompt == 0) {
4994 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_INFO_RESPONSE);
4995 ssh2_pkt_adduint32(ssh, s->num_prompts);
4996 }
4997 if (s->need_pw) { /* only add pw if we just got one! */
4998 ssh2_pkt_addstring(ssh, s->password);
4999 memset(s->password, 0, sizeof(s->password));
5000 s->curr_prompt++;
5001 }
5002 if (s->curr_prompt >= s->num_prompts) {
5003 ssh2_pkt_send(ssh);
5004 } else {
5005 /*
5006 * If there are prompts remaining, we set
5007 * `gotit' so that we won't attempt to get
5008 * another packet. Then we go back round the
5009 * loop and will end up retrieving another
5010 * prompt out of the existing packet. Funky or
5011 * what?
5012 */
5013 s->gotit = TRUE;
5014 }
5015 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
5016 } else {
5017 c_write_str(ssh, "No supported authentication methods"
5018 " left to try!\r\n");
5019 logevent("No supported authentications offered."
5020 " Disconnecting");
5021 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5022 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5023 ssh2_pkt_addstring(ssh, "No supported authentication"
5024 " methods available");
5025 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5026 ssh2_pkt_send(ssh);
5027 ssh->state = SSH_STATE_CLOSED;
5028 crReturnV;
5029 }
5030 }
5031 } while (!s->we_are_in);
5032
5033 /*
5034 * Now we're authenticated for the connection protocol. The
5035 * connection protocol will automatically have started at this
5036 * point; there's no need to send SERVICE_REQUEST.
5037 */
5038
5039 /*
5040 * So now create a channel with a session in it.
5041 */
5042 ssh->channels = newtree234(ssh_channelcmp);
5043 ssh->mainchan = smalloc(sizeof(struct ssh_channel));
5044 ssh->mainchan->ssh = ssh;
5045 ssh->mainchan->localid = alloc_channel_id(ssh);
5046 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN);
5047 ssh2_pkt_addstring(ssh, "session");
5048 ssh2_pkt_adduint32(ssh, ssh->mainchan->localid);
5049 ssh->mainchan->v.v2.locwindow = OUR_V2_WINSIZE;
5050 ssh2_pkt_adduint32(ssh, ssh->mainchan->v.v2.locwindow);/* our window size */
5051 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
5052 ssh2_pkt_send(ssh);
5053 crWaitUntilV(ispkt);
5054 if (ssh->pktin.type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
5055 bombout((ssh,"Server refused to open a session"));
5056 crReturnV;
5057 /* FIXME: error data comes back in FAILURE packet */
5058 }
5059 if (ssh2_pkt_getuint32(ssh) != ssh->mainchan->localid) {
5060 bombout((ssh,"Server's channel confirmation cited wrong channel"));
5061 crReturnV;
5062 }
5063 ssh->mainchan->remoteid = ssh2_pkt_getuint32(ssh);
5064 ssh->mainchan->type = CHAN_MAINSESSION;
5065 ssh->mainchan->closes = 0;
5066 ssh->mainchan->v.v2.remwindow = ssh2_pkt_getuint32(ssh);
5067 ssh->mainchan->v.v2.remmaxpkt = ssh2_pkt_getuint32(ssh);
5068 bufchain_init(&ssh->mainchan->v.v2.outbuffer);
5069 add234(ssh->channels, ssh->mainchan);
5070 logevent("Opened channel for session");
5071
5072 /*
5073 * Potentially enable X11 forwarding.
5074 */
5075 if (ssh->cfg.x11_forward) {
5076 char proto[20], data[64];
5077 logevent("Requesting X11 forwarding");
5078 ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
5079 data, sizeof(data), ssh->cfg.x11_auth);
5080 x11_get_real_auth(ssh->x11auth, ssh->cfg.x11_display);
5081 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5082 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
5083 ssh2_pkt_addstring(ssh, "x11-req");
5084 ssh2_pkt_addbool(ssh, 1); /* want reply */
5085 ssh2_pkt_addbool(ssh, 0); /* many connections */
5086 ssh2_pkt_addstring(ssh, proto);
5087 ssh2_pkt_addstring(ssh, data);
5088 ssh2_pkt_adduint32(ssh, x11_get_screen_number(ssh->cfg.x11_display));
5089 ssh2_pkt_send(ssh);
5090
5091 do {
5092 crWaitUntilV(ispkt);
5093 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5094 unsigned i = ssh2_pkt_getuint32(ssh);
5095 struct ssh_channel *c;
5096 c = find234(ssh->channels, &i, ssh_channelfind);
5097 if (!c)
5098 continue; /* nonexistent channel */
5099 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5100 }
5101 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5102
5103 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5104 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5105 bombout((ssh,"Unexpected response to X11 forwarding request:"
5106 " packet type %d", ssh->pktin.type));
5107 crReturnV;
5108 }
5109 logevent("X11 forwarding refused");
5110 } else {
5111 logevent("X11 forwarding enabled");
5112 ssh->X11_fwd_enabled = TRUE;
5113 }
5114 }
5115
5116 /*
5117 * Enable port forwardings.
5118 */
5119 {
5120 char type;
5121 int n;
5122 int sport,dport,sserv,dserv;
5123 char sports[256], dports[256], saddr[256], host[256];
5124
5125 ssh->rportfwds = newtree234(ssh_rportcmp_ssh2);
5126 /* Add port forwardings. */
5127 ssh->portfwd_strptr = ssh->cfg.portfwd;
5128 while (*ssh->portfwd_strptr) {
5129 type = *ssh->portfwd_strptr++;
5130 saddr[0] = '\0';
5131 n = 0;
5132 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != '\t') {
5133 if (*ssh->portfwd_strptr == ':') {
5134 /*
5135 * We've seen a colon in the middle of the
5136 * source port number. This means that
5137 * everything we've seen until now is the
5138 * source _address_, so we'll move it into
5139 * saddr and start sports from the beginning
5140 * again.
5141 */
5142 ssh->portfwd_strptr++;
5143 sports[n] = '\0';
5144 strcpy(saddr, sports);
5145 n = 0;
5146 }
5147 if (n < 255) sports[n++] = *ssh->portfwd_strptr++;
5148 }
5149 sports[n] = 0;
5150 if (*ssh->portfwd_strptr == '\t')
5151 ssh->portfwd_strptr++;
5152 n = 0;
5153 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':') {
5154 if (n < 255) host[n++] = *ssh->portfwd_strptr++;
5155 }
5156 host[n] = 0;
5157 if (*ssh->portfwd_strptr == ':')
5158 ssh->portfwd_strptr++;
5159 n = 0;
5160 while (*ssh->portfwd_strptr) {
5161 if (n < 255) dports[n++] = *ssh->portfwd_strptr++;
5162 }
5163 dports[n] = 0;
5164 ssh->portfwd_strptr++;
5165 dport = atoi(dports);
5166 dserv = 0;
5167 if (dport == 0) {
5168 dserv = 1;
5169 dport = net_service_lookup(dports);
5170 if (!dport) {
5171 logeventf(ssh, "Service lookup failed for destination"
5172 " port \"%s\"", dports);
5173 }
5174 }
5175 sport = atoi(sports);
5176 sserv = 0;
5177 if (sport == 0) {
5178 sserv = 1;
5179 sport = net_service_lookup(sports);
5180 if (!sport) {
5181 logeventf(ssh, "Service lookup failed for source"
5182 " port \"%s\"", sports);
5183 }
5184 }
5185 if (sport && dport) {
5186 if (type == 'L') {
5187 pfd_addforward(host, dport, *saddr ? saddr : NULL,
5188 sport, ssh, ssh->cfg.lport_acceptall);
5189 logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
5190 " forwarding to %s:%.*s%.*s%d%.*s",
5191 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
5192 (int)(*saddr?1:0), ":",
5193 (int)(sserv ? strlen(sports) : 0), sports,
5194 sserv, "(", sport, sserv, ")",
5195 host,
5196 (int)(dserv ? strlen(dports) : 0), dports,
5197 dserv, "(", dport, dserv, ")");
5198 } else {
5199 struct ssh_rportfwd *pf;
5200 pf = smalloc(sizeof(*pf));
5201 strcpy(pf->dhost, host);
5202 pf->dport = dport;
5203 pf->sport = sport;
5204 if (add234(ssh->rportfwds, pf) != pf) {
5205 logeventf(ssh, "Duplicate remote port forwarding"
5206 " to %s:%d", host, dport);
5207 sfree(pf);
5208 } else {
5209 logeventf(ssh, "Requesting remote port "
5210 "%.*s%.*s%.*s%.*s%d%.*s"
5211 " forward to %s:%.*s%.*s%d%.*s",
5212 (int)(*saddr?strlen(saddr):0),
5213 *saddr?saddr:NULL,
5214 (int)(*saddr?1:0), ":",
5215 (int)(sserv ? strlen(sports) : 0), sports,
5216 sserv, "(", sport, sserv, ")",
5217 host,
5218 (int)(dserv ? strlen(dports) : 0), dports,
5219 dserv, "(", dport, dserv, ")");
5220 ssh2_pkt_init(ssh, SSH2_MSG_GLOBAL_REQUEST);
5221 ssh2_pkt_addstring(ssh, "tcpip-forward");
5222 ssh2_pkt_addbool(ssh, 1);/* want reply */
5223 if (*saddr)
5224 ssh2_pkt_addstring(ssh, saddr);
5225 if (ssh->cfg.rport_acceptall)
5226 ssh2_pkt_addstring(ssh, "0.0.0.0");
5227 else
5228 ssh2_pkt_addstring(ssh, "127.0.0.1");
5229 ssh2_pkt_adduint32(ssh, sport);
5230 ssh2_pkt_send(ssh);
5231
5232 do {
5233 crWaitUntilV(ispkt);
5234 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5235 unsigned i = ssh2_pkt_getuint32(ssh);
5236 struct ssh_channel *c;
5237 c = find234(ssh->channels, &i, ssh_channelfind);
5238 if (!c)
5239 continue;/* nonexistent channel */
5240 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5241 }
5242 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5243
5244 if (ssh->pktin.type != SSH2_MSG_REQUEST_SUCCESS) {
5245 if (ssh->pktin.type != SSH2_MSG_REQUEST_FAILURE) {
5246 bombout((ssh,"Unexpected response to port "
5247 "forwarding request: packet type %d",
5248 ssh->pktin.type));
5249 crReturnV;
5250 }
5251 logevent("Server refused this port forwarding");
5252 } else {
5253 logevent("Remote port forwarding enabled");
5254 }
5255 }
5256 }
5257 }
5258 }
5259 }
5260
5261 /*
5262 * Potentially enable agent forwarding.
5263 */
5264 if (ssh->cfg.agentfwd && agent_exists()) {
5265 logevent("Requesting OpenSSH-style agent forwarding");
5266 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5267 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
5268 ssh2_pkt_addstring(ssh, "auth-agent-req@openssh.com");
5269 ssh2_pkt_addbool(ssh, 1); /* want reply */
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_CHANNEL_SUCCESS) {
5285 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5286 bombout((ssh,"Unexpected response to agent forwarding request:"
5287 " packet type %d", ssh->pktin.type));
5288 crReturnV;
5289 }
5290 logevent("Agent forwarding refused");
5291 } else {
5292 logevent("Agent forwarding enabled");
5293 ssh->agentfwd_enabled = TRUE;
5294 }
5295 }
5296
5297 /*
5298 * Now allocate a pty for the session.
5299 */
5300 if (!ssh->cfg.nopty) {
5301 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5302 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid); /* recipient channel */
5303 ssh2_pkt_addstring(ssh, "pty-req");
5304 ssh2_pkt_addbool(ssh, 1); /* want reply */
5305 ssh2_pkt_addstring(ssh, ssh->cfg.termtype);
5306 ssh2_pkt_adduint32(ssh, ssh->term_width);
5307 ssh2_pkt_adduint32(ssh, ssh->term_height);
5308 ssh2_pkt_adduint32(ssh, 0); /* pixel width */
5309 ssh2_pkt_adduint32(ssh, 0); /* pixel height */
5310 ssh2_pkt_addstring_start(ssh);
5311 ssh2_pkt_addstring_data(ssh, "\0", 1); /* TTY_OP_END, no special options */
5312 ssh2_pkt_send(ssh);
5313 ssh->state = SSH_STATE_INTERMED;
5314
5315 do {
5316 crWaitUntilV(ispkt);
5317 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5318 unsigned i = ssh2_pkt_getuint32(ssh);
5319 struct ssh_channel *c;
5320 c = find234(ssh->channels, &i, ssh_channelfind);
5321 if (!c)
5322 continue; /* nonexistent channel */
5323 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5324 }
5325 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5326
5327 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5328 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5329 bombout((ssh,"Unexpected response to pty request:"
5330 " packet type %d", ssh->pktin.type));
5331 crReturnV;
5332 }
5333 c_write_str(ssh, "Server refused to allocate pty\r\n");
5334 ssh->editing = ssh->echoing = 1;
5335 } else {
5336 logevent("Allocated pty");
5337 }
5338 } else {
5339 ssh->editing = ssh->echoing = 1;
5340 }
5341
5342 /*
5343 * Start a shell or a remote command. We may have to attempt
5344 * this twice if the config data has provided a second choice
5345 * of command.
5346 */
5347 while (1) {
5348 int subsys;
5349 char *cmd;
5350
5351 if (ssh->fallback_cmd) {
5352 subsys = ssh->cfg.ssh_subsys2;
5353 cmd = ssh->cfg.remote_cmd_ptr2;
5354 } else {
5355 subsys = ssh->cfg.ssh_subsys;
5356 cmd = ssh->cfg.remote_cmd_ptr;
5357 }
5358
5359 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5360 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid); /* recipient channel */
5361 if (subsys) {
5362 ssh2_pkt_addstring(ssh, "subsystem");
5363 ssh2_pkt_addbool(ssh, 1); /* want reply */
5364 ssh2_pkt_addstring(ssh, cmd);
5365 } else if (*cmd) {
5366 ssh2_pkt_addstring(ssh, "exec");
5367 ssh2_pkt_addbool(ssh, 1); /* want reply */
5368 ssh2_pkt_addstring(ssh, cmd);
5369 } else {
5370 ssh2_pkt_addstring(ssh, "shell");
5371 ssh2_pkt_addbool(ssh, 1); /* want reply */
5372 }
5373 ssh2_pkt_send(ssh);
5374 do {
5375 crWaitUntilV(ispkt);
5376 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5377 unsigned i = ssh2_pkt_getuint32(ssh);
5378 struct ssh_channel *c;
5379 c = find234(ssh->channels, &i, ssh_channelfind);
5380 if (!c)
5381 continue; /* nonexistent channel */
5382 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5383 }
5384 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5385 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5386 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5387 bombout((ssh,"Unexpected response to shell/command request:"
5388 " packet type %d", ssh->pktin.type));
5389 crReturnV;
5390 }
5391 /*
5392 * We failed to start the command. If this is the
5393 * fallback command, we really are finished; if it's
5394 * not, and if the fallback command exists, try falling
5395 * back to it before complaining.
5396 */
5397 if (!ssh->fallback_cmd && ssh->cfg.remote_cmd_ptr2 != NULL) {
5398 logevent("Primary command failed; attempting fallback");
5399 ssh->fallback_cmd = TRUE;
5400 continue;
5401 }
5402 bombout((ssh,"Server refused to start a shell/command"));
5403 crReturnV;
5404 } else {
5405 logevent("Started a shell/command");
5406 }
5407 break;
5408 }
5409
5410 ssh->state = SSH_STATE_SESSION;
5411 if (ssh->size_needed)
5412 ssh_size(ssh, ssh->term_width, ssh->term_height);
5413 if (ssh->eof_needed)
5414 ssh_special(ssh, TS_EOF);
5415
5416 /*
5417 * Transfer data!
5418 */
5419 if (ssh->ldisc)
5420 ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */
5421 ssh->send_ok = 1;
5422 while (1) {
5423 crReturnV;
5424 s->try_send = FALSE;
5425 if (ispkt) {
5426 if (ssh->pktin.type == SSH2_MSG_CHANNEL_DATA ||
5427 ssh->pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA) {
5428 char *data;
5429 int length;
5430 unsigned i = ssh2_pkt_getuint32(ssh);
5431 struct ssh_channel *c;
5432 c = find234(ssh->channels, &i, ssh_channelfind);
5433 if (!c)
5434 continue; /* nonexistent channel */
5435 if (ssh->pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
5436 ssh2_pkt_getuint32(ssh) != SSH2_EXTENDED_DATA_STDERR)
5437 continue; /* extended but not stderr */
5438 ssh2_pkt_getstring(ssh, &data, &length);
5439 if (data) {
5440 int bufsize;
5441 c->v.v2.locwindow -= length;
5442 switch (c->type) {
5443 case CHAN_MAINSESSION:
5444 bufsize =
5445 from_backend(ssh->frontend, ssh->pktin.type ==
5446 SSH2_MSG_CHANNEL_EXTENDED_DATA,
5447 data, length);
5448 break;
5449 case CHAN_X11:
5450 bufsize = x11_send(c->u.x11.s, data, length);
5451 break;
5452 case CHAN_SOCKDATA:
5453 bufsize = pfd_send(c->u.pfd.s, data, length);
5454 break;
5455 case CHAN_AGENT:
5456 while (length > 0) {
5457 if (c->u.a.lensofar < 4) {
5458 int l = min(4 - c->u.a.lensofar, length);
5459 memcpy(c->u.a.msglen + c->u.a.lensofar,
5460 data, l);
5461 data += l;
5462 length -= l;
5463 c->u.a.lensofar += l;
5464 }
5465 if (c->u.a.lensofar == 4) {
5466 c->u.a.totallen =
5467 4 + GET_32BIT(c->u.a.msglen);
5468 c->u.a.message = smalloc(c->u.a.totallen);
5469 memcpy(c->u.a.message, c->u.a.msglen, 4);
5470 }
5471 if (c->u.a.lensofar >= 4 && length > 0) {
5472 int l =
5473 min(c->u.a.totallen - c->u.a.lensofar,
5474 length);
5475 memcpy(c->u.a.message + c->u.a.lensofar,
5476 data, l);
5477 data += l;
5478 length -= l;
5479 c->u.a.lensofar += l;
5480 }
5481 if (c->u.a.lensofar == c->u.a.totallen) {
5482 void *reply, *sentreply;
5483 int replylen;
5484 agent_query(c->u.a.message,
5485 c->u.a.totallen, &reply,
5486 &replylen);
5487 if (reply)
5488 sentreply = reply;
5489 else {
5490 /* Fake SSH_AGENT_FAILURE. */
5491 sentreply = "\0\0\0\1\5";
5492 replylen = 5;
5493 }
5494 ssh2_add_channel_data(c, sentreply, replylen);
5495 s->try_send = TRUE;
5496 if (reply)
5497 sfree(reply);
5498 sfree(c->u.a.message);
5499 c->u.a.lensofar = 0;
5500 }
5501 }
5502 bufsize = 0;
5503 break;
5504 }
5505 /*
5506 * If we are not buffering too much data,
5507 * enlarge the window again at the remote side.
5508 */
5509 if (bufsize < OUR_V2_WINSIZE)
5510 ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
5511 }
5512 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_EOF) {
5513 unsigned i = ssh2_pkt_getuint32(ssh);
5514 struct ssh_channel *c;
5515
5516 c = find234(ssh->channels, &i, ssh_channelfind);
5517 if (!c)
5518 continue; /* nonexistent channel */
5519
5520 if (c->type == CHAN_X11) {
5521 /*
5522 * Remote EOF on an X11 channel means we should
5523 * wrap up and close the channel ourselves.
5524 */
5525 x11_close(c->u.x11.s);
5526 sshfwd_close(c);
5527 } else if (c->type == CHAN_AGENT) {
5528 sshfwd_close(c);
5529 } else if (c->type == CHAN_SOCKDATA) {
5530 pfd_close(c->u.pfd.s);
5531 sshfwd_close(c);
5532 }
5533 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_CLOSE) {
5534 unsigned i = ssh2_pkt_getuint32(ssh);
5535 struct ssh_channel *c;
5536
5537 c = find234(ssh->channels, &i, ssh_channelfind);
5538 if (!c || ((int)c->remoteid) == -1) {
5539 bombout((ssh,"Received CHANNEL_CLOSE for %s channel %d\n",
5540 c ? "half-open" : "nonexistent", i));
5541 }
5542 /* Do pre-close processing on the channel. */
5543 switch (c->type) {
5544 case CHAN_MAINSESSION:
5545 break; /* nothing to see here, move along */
5546 case CHAN_X11:
5547 if (c->u.x11.s != NULL)
5548 x11_close(c->u.x11.s);
5549 sshfwd_close(c);
5550 break;
5551 case CHAN_AGENT:
5552 sshfwd_close(c);
5553 break;
5554 case CHAN_SOCKDATA:
5555 if (c->u.pfd.s != NULL)
5556 pfd_close(c->u.pfd.s);
5557 sshfwd_close(c);
5558 break;
5559 }
5560 if (c->closes == 0) {
5561 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
5562 ssh2_pkt_adduint32(ssh, c->remoteid);
5563 ssh2_pkt_send(ssh);
5564 }
5565 del234(ssh->channels, c);
5566 bufchain_clear(&c->v.v2.outbuffer);
5567 sfree(c);
5568
5569 /*
5570 * See if that was the last channel left open.
5571 */
5572 if (count234(ssh->channels) == 0) {
5573 #if 0
5574 /*
5575 * We used to send SSH_MSG_DISCONNECT here,
5576 * because I'd believed that _every_ conforming
5577 * SSH2 connection had to end with a disconnect
5578 * being sent by at least one side; apparently
5579 * I was wrong and it's perfectly OK to
5580 * unceremoniously slam the connection shut
5581 * when you're done, and indeed OpenSSH feels
5582 * this is more polite than sending a
5583 * DISCONNECT. So now we don't.
5584 */
5585 logevent("All channels closed. Disconnecting");
5586 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5587 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5588 ssh2_pkt_addstring(ssh, "All open channels closed");
5589 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5590 ssh2_pkt_send(ssh);
5591 #endif
5592 ssh->state = SSH_STATE_CLOSED;
5593 crReturnV;
5594 }
5595 continue; /* remote sends close; ignore (FIXME) */
5596 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5597 unsigned i = ssh2_pkt_getuint32(ssh);
5598 struct ssh_channel *c;
5599 c = find234(ssh->channels, &i, ssh_channelfind);
5600 if (!c || c->closes)
5601 continue; /* nonexistent or closing channel */
5602 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5603 s->try_send = TRUE;
5604 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
5605 unsigned i = ssh2_pkt_getuint32(ssh);
5606 struct ssh_channel *c;
5607 c = find234(ssh->channels, &i, ssh_channelfind);
5608 if (!c)
5609 continue; /* nonexistent channel */
5610 if (c->type != CHAN_SOCKDATA_DORMANT)
5611 continue; /* dunno why they're confirming this */
5612 c->remoteid = ssh2_pkt_getuint32(ssh);
5613 c->type = CHAN_SOCKDATA;
5614 c->v.v2.remwindow = ssh2_pkt_getuint32(ssh);
5615 c->v.v2.remmaxpkt = ssh2_pkt_getuint32(ssh);
5616 if (c->u.pfd.s)
5617 pfd_confirm(c->u.pfd.s);
5618 if (c->closes) {
5619 /*
5620 * We have a pending close on this channel,
5621 * which we decided on before the server acked
5622 * the channel open. So now we know the
5623 * remoteid, we can close it again.
5624 */
5625 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
5626 ssh2_pkt_adduint32(ssh, c->remoteid);
5627 ssh2_pkt_send(ssh);
5628 }
5629 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN_FAILURE) {
5630 unsigned i = ssh2_pkt_getuint32(ssh);
5631 struct ssh_channel *c;
5632 c = find234(ssh->channels, &i, ssh_channelfind);
5633 if (!c)
5634 continue; /* nonexistent channel */
5635 if (c->type != CHAN_SOCKDATA_DORMANT)
5636 continue; /* dunno why they're failing this */
5637
5638 logevent("Forwarded connection refused by server");
5639
5640 pfd_close(c->u.pfd.s);
5641
5642 del234(ssh->channels, c);
5643 sfree(c);
5644 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_REQUEST) {
5645 unsigned localid;
5646 char *type;
5647 int typelen, want_reply;
5648 struct ssh_channel *c;
5649
5650 localid = ssh2_pkt_getuint32(ssh);
5651 ssh2_pkt_getstring(ssh, &type, &typelen);
5652 want_reply = ssh2_pkt_getbool(ssh);
5653
5654 /*
5655 * First, check that the channel exists. Otherwise,
5656 * we can instantly disconnect with a rude message.
5657 */
5658 c = find234(ssh->channels, &localid, ssh_channelfind);
5659 if (!c) {
5660 char buf[80];
5661 sprintf(buf, "Received channel request for nonexistent"
5662 " channel %d", localid);
5663 logevent(buf);
5664 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5665 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5666 ssh2_pkt_addstring(ssh, buf);
5667 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5668 ssh2_pkt_send(ssh);
5669 connection_fatal("%s", buf);
5670 ssh->state = SSH_STATE_CLOSED;
5671 crReturnV;
5672 }
5673
5674 /*
5675 * Having got the channel number, we now look at
5676 * the request type string to see if it's something
5677 * we recognise.
5678 */
5679 if (typelen == 11 && !memcmp(type, "exit-status", 11) &&
5680 c == ssh->mainchan) {
5681 /* We recognise "exit-status" on the primary channel. */
5682 char buf[100];
5683 ssh->exitcode = ssh2_pkt_getuint32(ssh);
5684 sprintf(buf, "Server sent command exit status %d",
5685 ssh->exitcode);
5686 logevent(buf);
5687 if (want_reply) {
5688 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_SUCCESS);
5689 ssh2_pkt_adduint32(ssh, c->remoteid);
5690 ssh2_pkt_send(ssh);
5691 }
5692 } else {
5693 /*
5694 * This is a channel request we don't know
5695 * about, so we now either ignore the request
5696 * or respond with CHANNEL_FAILURE, depending
5697 * on want_reply.
5698 */
5699 if (want_reply) {
5700 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_FAILURE);
5701 ssh2_pkt_adduint32(ssh, c->remoteid);
5702 ssh2_pkt_send(ssh);
5703 }
5704 }
5705 } else if (ssh->pktin.type == SSH2_MSG_GLOBAL_REQUEST) {
5706 char *type;
5707 int typelen, want_reply;
5708
5709 ssh2_pkt_getstring(ssh, &type, &typelen);
5710 want_reply = ssh2_pkt_getbool(ssh);
5711
5712 /*
5713 * We currently don't support any global requests
5714 * at all, so we either ignore the request or
5715 * respond with REQUEST_FAILURE, depending on
5716 * want_reply.
5717 */
5718 if (want_reply) {
5719 ssh2_pkt_init(ssh, SSH2_MSG_REQUEST_FAILURE);
5720 ssh2_pkt_send(ssh);
5721 }
5722 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN) {
5723 char *type;
5724 int typelen;
5725 char *peeraddr;
5726 int peeraddrlen;
5727 int port;
5728 char *error = NULL;
5729 struct ssh_channel *c;
5730 unsigned remid, winsize, pktsize;
5731 ssh2_pkt_getstring(ssh, &type, &typelen);
5732 c = smalloc(sizeof(struct ssh_channel));
5733 c->ssh = ssh;
5734
5735 remid = ssh2_pkt_getuint32(ssh);
5736 winsize = ssh2_pkt_getuint32(ssh);
5737 pktsize = ssh2_pkt_getuint32(ssh);
5738 ssh2_pkt_getstring(ssh, &peeraddr, &peeraddrlen);
5739 port = ssh2_pkt_getuint32(ssh);
5740
5741 if (typelen == 3 && !memcmp(type, "x11", 3)) {
5742 char *addrstr = smalloc(peeraddrlen+1);
5743 memcpy(addrstr, peeraddr, peeraddrlen);
5744 peeraddr[peeraddrlen] = '\0';
5745
5746 if (!ssh->X11_fwd_enabled)
5747 error = "X11 forwarding is not enabled";
5748 else if (x11_init(&c->u.x11.s, ssh->cfg.x11_display, c,
5749 ssh->x11auth, addrstr, port) != NULL) {
5750 error = "Unable to open an X11 connection";
5751 } else {
5752 c->type = CHAN_X11;
5753 }
5754
5755 sfree(addrstr);
5756 } else if (typelen == 15 &&
5757 !memcmp(type, "forwarded-tcpip", 15)) {
5758 struct ssh_rportfwd pf, *realpf;
5759 char *dummy;
5760 int dummylen;
5761 ssh2_pkt_getstring(ssh, &dummy, &dummylen);/* skip address */
5762 pf.sport = ssh2_pkt_getuint32(ssh);
5763 realpf = find234(ssh->rportfwds, &pf, NULL);
5764 if (realpf == NULL) {
5765 error = "Remote port is not recognised";
5766 } else {
5767 char *e = pfd_newconnect(&c->u.pfd.s, realpf->dhost,
5768 realpf->dport, c);
5769 logeventf(ssh, "Received remote port open request"
5770 " for %s:%d", realpf->dhost, realpf->dport);
5771 if (e != NULL) {
5772 logeventf(ssh, "Port open failed: %s", e);
5773 error = "Port open failed";
5774 } else {
5775 logevent("Forwarded port opened successfully");
5776 c->type = CHAN_SOCKDATA;
5777 }
5778 }
5779 } else if (typelen == 22 &&
5780 !memcmp(type, "auth-agent@openssh.com", 3)) {
5781 if (!ssh->agentfwd_enabled)
5782 error = "Agent forwarding is not enabled";
5783 else {
5784 c->type = CHAN_AGENT; /* identify channel type */
5785 c->u.a.lensofar = 0;
5786 }
5787 } else {
5788 error = "Unsupported channel type requested";
5789 }
5790
5791 c->remoteid = remid;
5792 if (error) {
5793 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN_FAILURE);
5794 ssh2_pkt_adduint32(ssh, c->remoteid);
5795 ssh2_pkt_adduint32(ssh, SSH2_OPEN_CONNECT_FAILED);
5796 ssh2_pkt_addstring(ssh, error);
5797 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5798 ssh2_pkt_send(ssh);
5799 sfree(c);
5800 } else {
5801 c->localid = alloc_channel_id(ssh);
5802 c->closes = 0;
5803 c->v.v2.locwindow = OUR_V2_WINSIZE;
5804 c->v.v2.remwindow = winsize;
5805 c->v.v2.remmaxpkt = pktsize;
5806 bufchain_init(&c->v.v2.outbuffer);
5807 add234(ssh->channels, c);
5808 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
5809 ssh2_pkt_adduint32(ssh, c->remoteid);
5810 ssh2_pkt_adduint32(ssh, c->localid);
5811 ssh2_pkt_adduint32(ssh, c->v.v2.locwindow);
5812 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
5813 ssh2_pkt_send(ssh);
5814 }
5815 } else {
5816 bombout((ssh,"Strange packet received: type %d", ssh->pktin.type));
5817 crReturnV;
5818 }
5819 } else {
5820 /*
5821 * We have spare data. Add it to the channel buffer.
5822 */
5823 ssh2_add_channel_data(ssh->mainchan, (char *)in, inlen);
5824 s->try_send = TRUE;
5825 }
5826 if (s->try_send) {
5827 int i;
5828 struct ssh_channel *c;
5829 /*
5830 * Try to send data on all channels if we can.
5831 */
5832 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
5833 int bufsize;
5834 if (c->closes)
5835 continue; /* don't send on closing channels */
5836 bufsize = ssh2_try_send(c);
5837 if (bufsize == 0) {
5838 switch (c->type) {
5839 case CHAN_MAINSESSION:
5840 /* stdin need not receive an unthrottle
5841 * notification since it will be polled */
5842 break;
5843 case CHAN_X11:
5844 x11_unthrottle(c->u.x11.s);
5845 break;
5846 case CHAN_AGENT:
5847 /* agent sockets are request/response and need no
5848 * buffer management */
5849 break;
5850 case CHAN_SOCKDATA:
5851 pfd_unthrottle(c->u.pfd.s);
5852 break;
5853 }
5854 }
5855 }
5856 }
5857 }
5858
5859 crFinishV;
5860 }
5861
5862 /*
5863 * Handle the top-level SSH2 protocol.
5864 */
5865 static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
5866 {
5867 if (do_ssh2_transport(ssh, in, inlen, ispkt) == 0)
5868 return;
5869 do_ssh2_authconn(ssh, in, inlen, ispkt);
5870 }
5871
5872 /*
5873 * Called to set up the connection.
5874 *
5875 * Returns an error message, or NULL on success.
5876 */
5877 static char *ssh_init(void *frontend_handle, void **backend_handle,
5878 Config *cfg,
5879 char *host, int port, char **realhost, int nodelay)
5880 {
5881 char *p;
5882 Ssh ssh;
5883
5884 ssh = smalloc(sizeof(*ssh));
5885 ssh->cfg = *cfg; /* STRUCTURE COPY */
5886 ssh->s = NULL;
5887 ssh->cipher = NULL;
5888 ssh->v1_cipher_ctx = NULL;
5889 ssh->crcda_ctx = NULL;
5890 ssh->cscipher = NULL;
5891 ssh->cs_cipher_ctx = NULL;
5892 ssh->sccipher = NULL;
5893 ssh->sc_cipher_ctx = NULL;
5894 ssh->csmac = NULL;
5895 ssh->cs_mac_ctx = NULL;
5896 ssh->scmac = NULL;
5897 ssh->sc_mac_ctx = NULL;
5898 ssh->cscomp = NULL;
5899 ssh->cs_comp_ctx = NULL;
5900 ssh->sccomp = NULL;
5901 ssh->sc_comp_ctx = NULL;
5902 ssh->kex = NULL;
5903 ssh->hostkey = NULL;
5904 ssh->exitcode = -1;
5905 ssh->state = SSH_STATE_PREPACKET;
5906 ssh->size_needed = FALSE;
5907 ssh->eof_needed = FALSE;
5908 ssh->ldisc = NULL;
5909 ssh->logctx = NULL;
5910 {
5911 static const struct Packet empty = { 0, 0, NULL, NULL, 0 };
5912 ssh->pktin = ssh->pktout = empty;
5913 }
5914 ssh->deferred_send_data = NULL;
5915 ssh->deferred_len = 0;
5916 ssh->deferred_size = 0;
5917 ssh->fallback_cmd = 0;
5918 ssh->pkt_ctx = 0;
5919 ssh->x11auth = NULL;
5920 ssh->v1_compressing = FALSE;
5921 ssh->v2_outgoing_sequence = 0;
5922 ssh->ssh1_rdpkt_crstate = 0;
5923 ssh->ssh2_rdpkt_crstate = 0;
5924 ssh->do_ssh_init_crstate = 0;
5925 ssh->ssh_gotdata_crstate = 0;
5926 ssh->ssh1_protocol_crstate = 0;
5927 ssh->do_ssh1_login_crstate = 0;
5928 ssh->do_ssh2_transport_crstate = 0;
5929 ssh->do_ssh2_authconn_crstate = 0;
5930 ssh->do_ssh_init_state = NULL;
5931 ssh->do_ssh1_login_state = NULL;
5932 ssh->do_ssh2_transport_state = NULL;
5933 ssh->do_ssh2_authconn_state = NULL;
5934 ssh->mainchan = NULL;
5935 ssh->throttled_all = 0;
5936 ssh->v1_stdout_throttling = 0;
5937
5938 *backend_handle = ssh;
5939
5940 #ifdef MSCRYPTOAPI
5941 if (crypto_startup() == 0)
5942 return "Microsoft high encryption pack not installed!";
5943 #endif
5944
5945 ssh->frontend = frontend_handle;
5946 ssh->term_width = ssh->cfg.width;
5947 ssh->term_height = ssh->cfg.height;
5948
5949 ssh->send_ok = 0;
5950 ssh->editing = 0;
5951 ssh->echoing = 0;
5952 ssh->v1_throttle_count = 0;
5953 ssh->overall_bufsize = 0;
5954 ssh->fallback_cmd = 0;
5955
5956 ssh->protocol = NULL;
5957
5958 p = connect_to_host(ssh, host, port, realhost, nodelay);
5959 if (p != NULL)
5960 return p;
5961
5962 return NULL;
5963 }
5964
5965 /*
5966 * Reconfigure the SSH backend.
5967 *
5968 * Currently, this function does nothing very useful. In future,
5969 * however, we could do some handy things with it. For example, we
5970 * could make the port forwarding configurer active in the Change
5971 * Settings box, and this routine could close down existing
5972 * forwardings and open up new ones in response to changes.
5973 */
5974 static void ssh_reconfig(void *handle, Config *cfg)
5975 {
5976 Ssh ssh = (Ssh) handle;
5977 ssh->cfg = *cfg; /* STRUCTURE COPY */
5978 }
5979
5980 /*
5981 * Called to send data down the Telnet connection.
5982 */
5983 static int ssh_send(void *handle, char *buf, int len)
5984 {
5985 Ssh ssh = (Ssh) handle;
5986
5987 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
5988 return 0;
5989
5990 ssh->protocol(ssh, (unsigned char *)buf, len, 0);
5991
5992 return ssh_sendbuffer(ssh);
5993 }
5994
5995 /*
5996 * Called to query the current amount of buffered stdin data.
5997 */
5998 static int ssh_sendbuffer(void *handle)
5999 {
6000 Ssh ssh = (Ssh) handle;
6001 int override_value;
6002
6003 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
6004 return 0;
6005
6006 /*
6007 * If the SSH socket itself has backed up, add the total backup
6008 * size on that to any individual buffer on the stdin channel.
6009 */
6010 override_value = 0;
6011 if (ssh->throttled_all)
6012 override_value = ssh->overall_bufsize;
6013
6014 if (ssh->version == 1) {
6015 return override_value;
6016 } else if (ssh->version == 2) {
6017 if (!ssh->mainchan || ssh->mainchan->closes > 0)
6018 return override_value;
6019 else
6020 return (override_value +
6021 bufchain_size(&ssh->mainchan->v.v2.outbuffer));
6022 }
6023
6024 return 0;
6025 }
6026
6027 /*
6028 * Called to set the size of the window from SSH's POV.
6029 */
6030 static void ssh_size(void *handle, int width, int height)
6031 {
6032 Ssh ssh = (Ssh) handle;
6033
6034 ssh->term_width = width;
6035 ssh->term_height = height;
6036
6037 switch (ssh->state) {
6038 case SSH_STATE_BEFORE_SIZE:
6039 case SSH_STATE_PREPACKET:
6040 case SSH_STATE_CLOSED:
6041 break; /* do nothing */
6042 case SSH_STATE_INTERMED:
6043 ssh->size_needed = TRUE; /* buffer for later */
6044 break;
6045 case SSH_STATE_SESSION:
6046 if (!ssh->cfg.nopty) {
6047 if (ssh->version == 1) {
6048 send_packet(ssh, SSH1_CMSG_WINDOW_SIZE,
6049 PKT_INT, ssh->term_height,
6050 PKT_INT, ssh->term_width,
6051 PKT_INT, 0, PKT_INT, 0, PKT_END);
6052 } else {
6053 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
6054 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
6055 ssh2_pkt_addstring(ssh, "window-change");
6056 ssh2_pkt_addbool(ssh, 0);
6057 ssh2_pkt_adduint32(ssh, ssh->term_width);
6058 ssh2_pkt_adduint32(ssh, ssh->term_height);
6059 ssh2_pkt_adduint32(ssh, 0);
6060 ssh2_pkt_adduint32(ssh, 0);
6061 ssh2_pkt_send(ssh);
6062 }
6063 }
6064 break;
6065 }
6066 }
6067
6068 /*
6069 * Send Telnet special codes. TS_EOF is useful for `plink', so you
6070 * can send an EOF and collect resulting output (e.g. `plink
6071 * hostname sort').
6072 */
6073 static void ssh_special(void *handle, Telnet_Special code)
6074 {
6075 Ssh ssh = (Ssh) handle;
6076
6077 if (code == TS_EOF) {
6078 if (ssh->state != SSH_STATE_SESSION) {
6079 /*
6080 * Buffer the EOF in case we are pre-SESSION, so we can
6081 * send it as soon as we reach SESSION.
6082 */
6083 if (code == TS_EOF)
6084 ssh->eof_needed = TRUE;
6085 return;
6086 }
6087 if (ssh->version == 1) {
6088 send_packet(ssh, SSH1_CMSG_EOF, PKT_END);
6089 } else {
6090 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_EOF);
6091 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
6092 ssh2_pkt_send(ssh);
6093 }
6094 logevent("Sent EOF message");
6095 } else if (code == TS_PING) {
6096 if (ssh->state == SSH_STATE_CLOSED
6097 || ssh->state == SSH_STATE_PREPACKET) return;
6098 if (ssh->version == 1) {
6099 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE))
6100 send_packet(ssh, SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
6101 } else {
6102 ssh2_pkt_init(ssh, SSH2_MSG_IGNORE);
6103 ssh2_pkt_addstring_start(ssh);
6104 ssh2_pkt_send(ssh);
6105 }
6106 } else {
6107 /* do nothing */
6108 }
6109 }
6110
6111 void *new_sock_channel(void *handle, Socket s)
6112 {
6113 Ssh ssh = (Ssh) handle;
6114 struct ssh_channel *c;
6115 c = smalloc(sizeof(struct ssh_channel));
6116 c->ssh = ssh;
6117
6118 if (c) {
6119 c->remoteid = -1; /* to be set when open confirmed */
6120 c->localid = alloc_channel_id(ssh);
6121 c->closes = 0;
6122 c->type = CHAN_SOCKDATA_DORMANT;/* identify channel type */
6123 c->u.pfd.s = s;
6124 bufchain_init(&c->v.v2.outbuffer);
6125 add234(ssh->channels, c);
6126 }
6127 return c;
6128 }
6129
6130 /*
6131 * This is called when stdout/stderr (the entity to which
6132 * from_backend sends data) manages to clear some backlog.
6133 */
6134 static void ssh_unthrottle(void *handle, int bufsize)
6135 {
6136 Ssh ssh = (Ssh) handle;
6137 if (ssh->version == 1) {
6138 if (ssh->v1_stdout_throttling && bufsize < SSH1_BUFFER_LIMIT) {
6139 ssh->v1_stdout_throttling = 0;
6140 ssh1_throttle(ssh, -1);
6141 }
6142 } else {
6143 if (ssh->mainchan && ssh->mainchan->closes == 0)
6144 ssh2_set_window(ssh->mainchan, OUR_V2_WINSIZE - bufsize);
6145 }
6146 }
6147
6148 void ssh_send_port_open(void *channel, char *hostname, int port, char *org)
6149 {
6150 struct ssh_channel *c = (struct ssh_channel *)channel;
6151 Ssh ssh = c->ssh;
6152
6153 logeventf(ssh, "Opening forwarded connection to %s:%d", hostname, port);
6154
6155 if (ssh->version == 1) {
6156 send_packet(ssh, SSH1_MSG_PORT_OPEN,
6157 PKT_INT, c->localid,
6158 PKT_STR, hostname,
6159 PKT_INT, port,
6160 //PKT_STR, <org:orgport>,
6161 PKT_END);
6162 } else {
6163 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN);
6164 ssh2_pkt_addstring(ssh, "direct-tcpip");
6165 ssh2_pkt_adduint32(ssh, c->localid);
6166 c->v.v2.locwindow = OUR_V2_WINSIZE;
6167 ssh2_pkt_adduint32(ssh, c->v.v2.locwindow);/* our window size */
6168 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
6169 ssh2_pkt_addstring(ssh, hostname);
6170 ssh2_pkt_adduint32(ssh, port);
6171 /*
6172 * We make up values for the originator data; partly it's
6173 * too much hassle to keep track, and partly I'm not
6174 * convinced the server should be told details like that
6175 * about my local network configuration.
6176 */
6177 ssh2_pkt_addstring(ssh, "client-side-connection");
6178 ssh2_pkt_adduint32(ssh, 0);
6179 ssh2_pkt_send(ssh);
6180 }
6181 }
6182
6183
6184 static Socket ssh_socket(void *handle)
6185 {
6186 Ssh ssh = (Ssh) handle;
6187 return ssh->s;
6188 }
6189
6190 static int ssh_sendok(void *handle)
6191 {
6192 Ssh ssh = (Ssh) handle;
6193 return ssh->send_ok;
6194 }
6195
6196 static int ssh_ldisc(void *handle, int option)
6197 {
6198 Ssh ssh = (Ssh) handle;
6199 if (option == LD_ECHO)
6200 return ssh->echoing;
6201 if (option == LD_EDIT)
6202 return ssh->editing;
6203 return FALSE;
6204 }
6205
6206 static void ssh_provide_ldisc(void *handle, void *ldisc)
6207 {
6208 Ssh ssh = (Ssh) handle;
6209 ssh->ldisc = ldisc;
6210 }
6211
6212 static void ssh_provide_logctx(void *handle, void *logctx)
6213 {
6214 Ssh ssh = (Ssh) handle;
6215 ssh->logctx = logctx;
6216 }
6217
6218 static int ssh_return_exitcode(void *handle)
6219 {
6220 Ssh ssh = (Ssh) handle;
6221 return ssh->exitcode;
6222 }
6223
6224 /*
6225 * Gross hack: pscp will try to start SFTP but fall back to scp1 if
6226 * that fails. This variable is the means by which scp.c can reach
6227 * into the SSH code and find out which one it got.
6228 */
6229 extern int ssh_fallback_cmd(void *handle)
6230 {
6231 Ssh ssh = (Ssh) handle;
6232 return ssh->fallback_cmd;
6233 }
6234
6235 Backend ssh_backend = {
6236 ssh_init,
6237 ssh_reconfig,
6238 ssh_send,
6239 ssh_sendbuffer,
6240 ssh_size,
6241 ssh_special,
6242 ssh_socket,
6243 ssh_return_exitcode,
6244 ssh_sendok,
6245 ssh_ldisc,
6246 ssh_provide_ldisc,
6247 ssh_provide_logctx,
6248 ssh_unthrottle,
6249 22
6250 };
Local modifications for Simon Tatham's `PuTTY' SSH client and terminal emulator