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In merging the username and password input functions I inadvertently
[u/mdw/putty] / ssh.c
1 #include <stdio.h>
2 #include <stdlib.h>
3 #include <stdarg.h>
4 #include <assert.h>
5
6 #include "putty.h"
7 #include "tree234.h"
8 #include "ssh.h"
9
10 #ifndef FALSE
11 #define FALSE 0
12 #endif
13 #ifndef TRUE
14 #define TRUE 1
15 #endif
16
17 #define SSH1_MSG_DISCONNECT 1 /* 0x1 */
18 #define SSH1_SMSG_PUBLIC_KEY 2 /* 0x2 */
19 #define SSH1_CMSG_SESSION_KEY 3 /* 0x3 */
20 #define SSH1_CMSG_USER 4 /* 0x4 */
21 #define SSH1_CMSG_AUTH_RSA 6 /* 0x6 */
22 #define SSH1_SMSG_AUTH_RSA_CHALLENGE 7 /* 0x7 */
23 #define SSH1_CMSG_AUTH_RSA_RESPONSE 8 /* 0x8 */
24 #define SSH1_CMSG_AUTH_PASSWORD 9 /* 0x9 */
25 #define SSH1_CMSG_REQUEST_PTY 10 /* 0xa */
26 #define SSH1_CMSG_WINDOW_SIZE 11 /* 0xb */
27 #define SSH1_CMSG_EXEC_SHELL 12 /* 0xc */
28 #define SSH1_CMSG_EXEC_CMD 13 /* 0xd */
29 #define SSH1_SMSG_SUCCESS 14 /* 0xe */
30 #define SSH1_SMSG_FAILURE 15 /* 0xf */
31 #define SSH1_CMSG_STDIN_DATA 16 /* 0x10 */
32 #define SSH1_SMSG_STDOUT_DATA 17 /* 0x11 */
33 #define SSH1_SMSG_STDERR_DATA 18 /* 0x12 */
34 #define SSH1_CMSG_EOF 19 /* 0x13 */
35 #define SSH1_SMSG_EXIT_STATUS 20 /* 0x14 */
36 #define SSH1_MSG_CHANNEL_OPEN_CONFIRMATION 21 /* 0x15 */
37 #define SSH1_MSG_CHANNEL_OPEN_FAILURE 22 /* 0x16 */
38 #define SSH1_MSG_CHANNEL_DATA 23 /* 0x17 */
39 #define SSH1_MSG_CHANNEL_CLOSE 24 /* 0x18 */
40 #define SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION 25 /* 0x19 */
41 #define SSH1_SMSG_X11_OPEN 27 /* 0x1b */
42 #define SSH1_CMSG_PORT_FORWARD_REQUEST 28 /* 0x1c */
43 #define SSH1_MSG_PORT_OPEN 29 /* 0x1d */
44 #define SSH1_CMSG_AGENT_REQUEST_FORWARDING 30 /* 0x1e */
45 #define SSH1_SMSG_AGENT_OPEN 31 /* 0x1f */
46 #define SSH1_MSG_IGNORE 32 /* 0x20 */
47 #define SSH1_CMSG_EXIT_CONFIRMATION 33 /* 0x21 */
48 #define SSH1_CMSG_X11_REQUEST_FORWARDING 34 /* 0x22 */
49 #define SSH1_CMSG_AUTH_RHOSTS_RSA 35 /* 0x23 */
50 #define SSH1_MSG_DEBUG 36 /* 0x24 */
51 #define SSH1_CMSG_REQUEST_COMPRESSION 37 /* 0x25 */
52 #define SSH1_CMSG_AUTH_TIS 39 /* 0x27 */
53 #define SSH1_SMSG_AUTH_TIS_CHALLENGE 40 /* 0x28 */
54 #define SSH1_CMSG_AUTH_TIS_RESPONSE 41 /* 0x29 */
55 #define SSH1_CMSG_AUTH_CCARD 70 /* 0x46 */
56 #define SSH1_SMSG_AUTH_CCARD_CHALLENGE 71 /* 0x47 */
57 #define SSH1_CMSG_AUTH_CCARD_RESPONSE 72 /* 0x48 */
58
59 #define SSH1_AUTH_TIS 5 /* 0x5 */
60 #define SSH1_AUTH_CCARD 16 /* 0x10 */
61
62 #define SSH1_PROTOFLAG_SCREEN_NUMBER 1 /* 0x1 */
63 /* Mask for protoflags we will echo back to server if seen */
64 #define SSH1_PROTOFLAGS_SUPPORTED 0 /* 0x1 */
65
66 #define SSH2_MSG_DISCONNECT 1 /* 0x1 */
67 #define SSH2_MSG_IGNORE 2 /* 0x2 */
68 #define SSH2_MSG_UNIMPLEMENTED 3 /* 0x3 */
69 #define SSH2_MSG_DEBUG 4 /* 0x4 */
70 #define SSH2_MSG_SERVICE_REQUEST 5 /* 0x5 */
71 #define SSH2_MSG_SERVICE_ACCEPT 6 /* 0x6 */
72 #define SSH2_MSG_KEXINIT 20 /* 0x14 */
73 #define SSH2_MSG_NEWKEYS 21 /* 0x15 */
74 #define SSH2_MSG_KEXDH_INIT 30 /* 0x1e */
75 #define SSH2_MSG_KEXDH_REPLY 31 /* 0x1f */
76 #define SSH2_MSG_KEX_DH_GEX_REQUEST 30 /* 0x1e */
77 #define SSH2_MSG_KEX_DH_GEX_GROUP 31 /* 0x1f */
78 #define SSH2_MSG_KEX_DH_GEX_INIT 32 /* 0x20 */
79 #define SSH2_MSG_KEX_DH_GEX_REPLY 33 /* 0x21 */
80 #define SSH2_MSG_USERAUTH_REQUEST 50 /* 0x32 */
81 #define SSH2_MSG_USERAUTH_FAILURE 51 /* 0x33 */
82 #define SSH2_MSG_USERAUTH_SUCCESS 52 /* 0x34 */
83 #define SSH2_MSG_USERAUTH_BANNER 53 /* 0x35 */
84 #define SSH2_MSG_USERAUTH_PK_OK 60 /* 0x3c */
85 #define SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ 60 /* 0x3c */
86 #define SSH2_MSG_USERAUTH_INFO_REQUEST 60 /* 0x3c */
87 #define SSH2_MSG_USERAUTH_INFO_RESPONSE 61 /* 0x3d */
88 #define SSH2_MSG_GLOBAL_REQUEST 80 /* 0x50 */
89 #define SSH2_MSG_REQUEST_SUCCESS 81 /* 0x51 */
90 #define SSH2_MSG_REQUEST_FAILURE 82 /* 0x52 */
91 #define SSH2_MSG_CHANNEL_OPEN 90 /* 0x5a */
92 #define SSH2_MSG_CHANNEL_OPEN_CONFIRMATION 91 /* 0x5b */
93 #define SSH2_MSG_CHANNEL_OPEN_FAILURE 92 /* 0x5c */
94 #define SSH2_MSG_CHANNEL_WINDOW_ADJUST 93 /* 0x5d */
95 #define SSH2_MSG_CHANNEL_DATA 94 /* 0x5e */
96 #define SSH2_MSG_CHANNEL_EXTENDED_DATA 95 /* 0x5f */
97 #define SSH2_MSG_CHANNEL_EOF 96 /* 0x60 */
98 #define SSH2_MSG_CHANNEL_CLOSE 97 /* 0x61 */
99 #define SSH2_MSG_CHANNEL_REQUEST 98 /* 0x62 */
100 #define SSH2_MSG_CHANNEL_SUCCESS 99 /* 0x63 */
101 #define SSH2_MSG_CHANNEL_FAILURE 100 /* 0x64 */
102
103 /*
104 * Packet type contexts, so that ssh2_pkt_type can correctly decode
105 * the ambiguous type numbers back into the correct type strings.
106 */
107 #define SSH2_PKTCTX_DHGROUP1 0x0001
108 #define SSH2_PKTCTX_DHGEX 0x0002
109 #define SSH2_PKTCTX_PUBLICKEY 0x0010
110 #define SSH2_PKTCTX_PASSWORD 0x0020
111 #define SSH2_PKTCTX_KBDINTER 0x0040
112 #define SSH2_PKTCTX_AUTH_MASK 0x00F0
113
114 #define SSH2_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT 1 /* 0x1 */
115 #define SSH2_DISCONNECT_PROTOCOL_ERROR 2 /* 0x2 */
116 #define SSH2_DISCONNECT_KEY_EXCHANGE_FAILED 3 /* 0x3 */
117 #define SSH2_DISCONNECT_HOST_AUTHENTICATION_FAILED 4 /* 0x4 */
118 #define SSH2_DISCONNECT_MAC_ERROR 5 /* 0x5 */
119 #define SSH2_DISCONNECT_COMPRESSION_ERROR 6 /* 0x6 */
120 #define SSH2_DISCONNECT_SERVICE_NOT_AVAILABLE 7 /* 0x7 */
121 #define SSH2_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED 8 /* 0x8 */
122 #define SSH2_DISCONNECT_HOST_KEY_NOT_VERIFIABLE 9 /* 0x9 */
123 #define SSH2_DISCONNECT_CONNECTION_LOST 10 /* 0xa */
124 #define SSH2_DISCONNECT_BY_APPLICATION 11 /* 0xb */
125 #define SSH2_DISCONNECT_TOO_MANY_CONNECTIONS 12 /* 0xc */
126 #define SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER 13 /* 0xd */
127 #define SSH2_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE 14 /* 0xe */
128 #define SSH2_DISCONNECT_ILLEGAL_USER_NAME 15 /* 0xf */
129
130 static const char *const ssh2_disconnect_reasons[] = {
131 NULL,
132 "SSH_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT",
133 "SSH_DISCONNECT_PROTOCOL_ERROR",
134 "SSH_DISCONNECT_KEY_EXCHANGE_FAILED",
135 "SSH_DISCONNECT_HOST_AUTHENTICATION_FAILED",
136 "SSH_DISCONNECT_MAC_ERROR",
137 "SSH_DISCONNECT_COMPRESSION_ERROR",
138 "SSH_DISCONNECT_SERVICE_NOT_AVAILABLE",
139 "SSH_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED",
140 "SSH_DISCONNECT_HOST_KEY_NOT_VERIFIABLE",
141 "SSH_DISCONNECT_CONNECTION_LOST",
142 "SSH_DISCONNECT_BY_APPLICATION",
143 "SSH_DISCONNECT_TOO_MANY_CONNECTIONS",
144 "SSH_DISCONNECT_AUTH_CANCELLED_BY_USER",
145 "SSH_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE",
146 "SSH_DISCONNECT_ILLEGAL_USER_NAME",
147 };
148
149 #define SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED 1 /* 0x1 */
150 #define SSH2_OPEN_CONNECT_FAILED 2 /* 0x2 */
151 #define SSH2_OPEN_UNKNOWN_CHANNEL_TYPE 3 /* 0x3 */
152 #define SSH2_OPEN_RESOURCE_SHORTAGE 4 /* 0x4 */
153
154 #define SSH2_EXTENDED_DATA_STDERR 1 /* 0x1 */
155
156 /*
157 * Various remote-bug flags.
158 */
159 #define BUG_CHOKES_ON_SSH1_IGNORE 1
160 #define BUG_SSH2_HMAC 2
161 #define BUG_NEEDS_SSH1_PLAIN_PASSWORD 4
162 #define BUG_CHOKES_ON_RSA 8
163 #define BUG_SSH2_RSA_PADDING 16
164 #define BUG_SSH2_DERIVEKEY 32
165 #define BUG_SSH2_DH_GEX 64
166 #define BUG_SSH2_PK_SESSIONID 128
167
168 #define translate(x) if (type == x) return #x
169 #define translatec(x,ctx) if (type == x && (pkt_ctx & ctx)) return #x
170 static char *ssh1_pkt_type(int type)
171 {
172 translate(SSH1_MSG_DISCONNECT);
173 translate(SSH1_SMSG_PUBLIC_KEY);
174 translate(SSH1_CMSG_SESSION_KEY);
175 translate(SSH1_CMSG_USER);
176 translate(SSH1_CMSG_AUTH_RSA);
177 translate(SSH1_SMSG_AUTH_RSA_CHALLENGE);
178 translate(SSH1_CMSG_AUTH_RSA_RESPONSE);
179 translate(SSH1_CMSG_AUTH_PASSWORD);
180 translate(SSH1_CMSG_REQUEST_PTY);
181 translate(SSH1_CMSG_WINDOW_SIZE);
182 translate(SSH1_CMSG_EXEC_SHELL);
183 translate(SSH1_CMSG_EXEC_CMD);
184 translate(SSH1_SMSG_SUCCESS);
185 translate(SSH1_SMSG_FAILURE);
186 translate(SSH1_CMSG_STDIN_DATA);
187 translate(SSH1_SMSG_STDOUT_DATA);
188 translate(SSH1_SMSG_STDERR_DATA);
189 translate(SSH1_CMSG_EOF);
190 translate(SSH1_SMSG_EXIT_STATUS);
191 translate(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION);
192 translate(SSH1_MSG_CHANNEL_OPEN_FAILURE);
193 translate(SSH1_MSG_CHANNEL_DATA);
194 translate(SSH1_MSG_CHANNEL_CLOSE);
195 translate(SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION);
196 translate(SSH1_SMSG_X11_OPEN);
197 translate(SSH1_CMSG_PORT_FORWARD_REQUEST);
198 translate(SSH1_MSG_PORT_OPEN);
199 translate(SSH1_CMSG_AGENT_REQUEST_FORWARDING);
200 translate(SSH1_SMSG_AGENT_OPEN);
201 translate(SSH1_MSG_IGNORE);
202 translate(SSH1_CMSG_EXIT_CONFIRMATION);
203 translate(SSH1_CMSG_X11_REQUEST_FORWARDING);
204 translate(SSH1_CMSG_AUTH_RHOSTS_RSA);
205 translate(SSH1_MSG_DEBUG);
206 translate(SSH1_CMSG_REQUEST_COMPRESSION);
207 translate(SSH1_CMSG_AUTH_TIS);
208 translate(SSH1_SMSG_AUTH_TIS_CHALLENGE);
209 translate(SSH1_CMSG_AUTH_TIS_RESPONSE);
210 translate(SSH1_CMSG_AUTH_CCARD);
211 translate(SSH1_SMSG_AUTH_CCARD_CHALLENGE);
212 translate(SSH1_CMSG_AUTH_CCARD_RESPONSE);
213 return "unknown";
214 }
215 static char *ssh2_pkt_type(int pkt_ctx, int type)
216 {
217 translate(SSH2_MSG_DISCONNECT);
218 translate(SSH2_MSG_IGNORE);
219 translate(SSH2_MSG_UNIMPLEMENTED);
220 translate(SSH2_MSG_DEBUG);
221 translate(SSH2_MSG_SERVICE_REQUEST);
222 translate(SSH2_MSG_SERVICE_ACCEPT);
223 translate(SSH2_MSG_KEXINIT);
224 translate(SSH2_MSG_NEWKEYS);
225 translatec(SSH2_MSG_KEXDH_INIT, SSH2_PKTCTX_DHGROUP1);
226 translatec(SSH2_MSG_KEXDH_REPLY, SSH2_PKTCTX_DHGROUP1);
227 translatec(SSH2_MSG_KEX_DH_GEX_REQUEST, SSH2_PKTCTX_DHGEX);
228 translatec(SSH2_MSG_KEX_DH_GEX_GROUP, SSH2_PKTCTX_DHGEX);
229 translatec(SSH2_MSG_KEX_DH_GEX_INIT, SSH2_PKTCTX_DHGEX);
230 translatec(SSH2_MSG_KEX_DH_GEX_REPLY, SSH2_PKTCTX_DHGEX);
231 translate(SSH2_MSG_USERAUTH_REQUEST);
232 translate(SSH2_MSG_USERAUTH_FAILURE);
233 translate(SSH2_MSG_USERAUTH_SUCCESS);
234 translate(SSH2_MSG_USERAUTH_BANNER);
235 translatec(SSH2_MSG_USERAUTH_PK_OK, SSH2_PKTCTX_PUBLICKEY);
236 translatec(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, SSH2_PKTCTX_PASSWORD);
237 translatec(SSH2_MSG_USERAUTH_INFO_REQUEST, SSH2_PKTCTX_KBDINTER);
238 translatec(SSH2_MSG_USERAUTH_INFO_RESPONSE, SSH2_PKTCTX_KBDINTER);
239 translate(SSH2_MSG_GLOBAL_REQUEST);
240 translate(SSH2_MSG_REQUEST_SUCCESS);
241 translate(SSH2_MSG_REQUEST_FAILURE);
242 translate(SSH2_MSG_CHANNEL_OPEN);
243 translate(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
244 translate(SSH2_MSG_CHANNEL_OPEN_FAILURE);
245 translate(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
246 translate(SSH2_MSG_CHANNEL_DATA);
247 translate(SSH2_MSG_CHANNEL_EXTENDED_DATA);
248 translate(SSH2_MSG_CHANNEL_EOF);
249 translate(SSH2_MSG_CHANNEL_CLOSE);
250 translate(SSH2_MSG_CHANNEL_REQUEST);
251 translate(SSH2_MSG_CHANNEL_SUCCESS);
252 translate(SSH2_MSG_CHANNEL_FAILURE);
253 return "unknown";
254 }
255 #undef translate
256 #undef translatec
257
258 #define GET_32BIT(cp) \
259 (((unsigned long)(unsigned char)(cp)[0] << 24) | \
260 ((unsigned long)(unsigned char)(cp)[1] << 16) | \
261 ((unsigned long)(unsigned char)(cp)[2] << 8) | \
262 ((unsigned long)(unsigned char)(cp)[3]))
263
264 #define PUT_32BIT(cp, value) { \
265 (cp)[0] = (unsigned char)((value) >> 24); \
266 (cp)[1] = (unsigned char)((value) >> 16); \
267 (cp)[2] = (unsigned char)((value) >> 8); \
268 (cp)[3] = (unsigned char)(value); }
269
270 enum { PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR, PKT_BIGNUM };
271
272 /* Coroutine mechanics for the sillier bits of the code */
273 #define crBegin(v) { int *crLine = &v; switch(v) { case 0:;
274 #define crState(t) \
275 struct t *s; \
276 if (!ssh->t) ssh->t = smalloc(sizeof(struct t)); \
277 s = ssh->t;
278 #define crFinish(z) } *crLine = 0; return (z); }
279 #define crFinishV } *crLine = 0; return; }
280 #define crReturn(z) \
281 do {\
282 *crLine =__LINE__; return (z); case __LINE__:;\
283 } while (0)
284 #define crReturnV \
285 do {\
286 *crLine=__LINE__; return; case __LINE__:;\
287 } while (0)
288 #define crStop(z) do{ *crLine = 0; return (z); }while(0)
289 #define crStopV do{ *crLine = 0; return; }while(0)
290 #define crWaitUntil(c) do { crReturn(0); } while (!(c))
291 #define crWaitUntilV(c) do { crReturnV; } while (!(c))
292
293 typedef struct ssh_tag *Ssh;
294
295 static void ssh2_pkt_init(Ssh, int pkt_type);
296 static void ssh2_pkt_addbool(Ssh, unsigned char value);
297 static void ssh2_pkt_adduint32(Ssh, unsigned long value);
298 static void ssh2_pkt_addstring_start(Ssh);
299 static void ssh2_pkt_addstring_str(Ssh, char *data);
300 static void ssh2_pkt_addstring_data(Ssh, char *data, int len);
301 static void ssh2_pkt_addstring(Ssh, char *data);
302 static unsigned char *ssh2_mpint_fmt(Bignum b, int *len);
303 static void ssh2_pkt_addmp(Ssh, Bignum b);
304 static int ssh2_pkt_construct(Ssh);
305 static void ssh2_pkt_send(Ssh);
306
307 /*
308 * Buffer management constants. There are several of these for
309 * various different purposes:
310 *
311 * - SSH1_BUFFER_LIMIT is the amount of backlog that must build up
312 * on a local data stream before we throttle the whole SSH
313 * connection (in SSH1 only). Throttling the whole connection is
314 * pretty drastic so we set this high in the hope it won't
315 * happen very often.
316 *
317 * - SSH_MAX_BACKLOG is the amount of backlog that must build up
318 * on the SSH connection itself before we defensively throttle
319 * _all_ local data streams. This is pretty drastic too (though
320 * thankfully unlikely in SSH2 since the window mechanism should
321 * ensure that the server never has any need to throttle its end
322 * of the connection), so we set this high as well.
323 *
324 * - OUR_V2_WINSIZE is the maximum window size we present on SSH2
325 * channels.
326 */
327
328 #define SSH1_BUFFER_LIMIT 32768
329 #define SSH_MAX_BACKLOG 32768
330 #define OUR_V2_WINSIZE 16384
331
332 const static struct ssh_kex *kex_algs[] = {
333 &ssh_diffiehellman_gex,
334 &ssh_diffiehellman
335 };
336
337 const static struct ssh_signkey *hostkey_algs[] = { &ssh_rsa, &ssh_dss };
338
339 static void *nullmac_make_context(void)
340 {
341 return NULL;
342 }
343 static void nullmac_free_context(void *handle)
344 {
345 }
346 static void nullmac_key(void *handle, unsigned char *key)
347 {
348 }
349 static void nullmac_generate(void *handle, unsigned char *blk, int len,
350 unsigned long seq)
351 {
352 }
353 static int nullmac_verify(void *handle, unsigned char *blk, int len,
354 unsigned long seq)
355 {
356 return 1;
357 }
358 const static struct ssh_mac ssh_mac_none = {
359 nullmac_make_context, nullmac_free_context, nullmac_key,
360 nullmac_generate, nullmac_verify, "none", 0
361 };
362 const static struct ssh_mac *macs[] = {
363 &ssh_sha1, &ssh_md5, &ssh_mac_none
364 };
365 const static struct ssh_mac *buggymacs[] = {
366 &ssh_sha1_buggy, &ssh_md5, &ssh_mac_none
367 };
368
369 static void *ssh_comp_none_init(void)
370 {
371 return NULL;
372 }
373 static void ssh_comp_none_cleanup(void *handle)
374 {
375 }
376 static int ssh_comp_none_block(void *handle, unsigned char *block, int len,
377 unsigned char **outblock, int *outlen)
378 {
379 return 0;
380 }
381 static int ssh_comp_none_disable(void *handle)
382 {
383 return 0;
384 }
385 const static struct ssh_compress ssh_comp_none = {
386 "none",
387 ssh_comp_none_init, ssh_comp_none_cleanup, ssh_comp_none_block,
388 ssh_comp_none_init, ssh_comp_none_cleanup, ssh_comp_none_block,
389 ssh_comp_none_disable, NULL
390 };
391 extern const struct ssh_compress ssh_zlib;
392 const static struct ssh_compress *compressions[] = {
393 &ssh_zlib, &ssh_comp_none
394 };
395
396 enum { /* channel types */
397 CHAN_MAINSESSION,
398 CHAN_X11,
399 CHAN_AGENT,
400 CHAN_SOCKDATA,
401 CHAN_SOCKDATA_DORMANT /* one the remote hasn't confirmed */
402 };
403
404 /*
405 * 2-3-4 tree storing channels.
406 */
407 struct ssh_channel {
408 Ssh ssh; /* pointer back to main context */
409 unsigned remoteid, localid;
410 int type;
411 /*
412 * In SSH1, this value contains four bits:
413 *
414 * 1 We have sent SSH1_MSG_CHANNEL_CLOSE.
415 * 2 We have sent SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION.
416 * 4 We have received SSH1_MSG_CHANNEL_CLOSE.
417 * 8 We have received SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION.
418 *
419 * A channel is completely finished with when all four bits are set.
420 */
421 int closes;
422 union {
423 struct ssh1_data_channel {
424 int throttling;
425 } v1;
426 struct ssh2_data_channel {
427 bufchain outbuffer;
428 unsigned remwindow, remmaxpkt;
429 unsigned locwindow;
430 } v2;
431 } v;
432 union {
433 struct ssh_agent_channel {
434 unsigned char *message;
435 unsigned char msglen[4];
436 int lensofar, totallen;
437 } a;
438 struct ssh_x11_channel {
439 Socket s;
440 } x11;
441 struct ssh_pfd_channel {
442 Socket s;
443 } pfd;
444 } u;
445 };
446
447 /*
448 * 2-3-4 tree storing remote->local port forwardings. SSH 1 and SSH
449 * 2 use this structure in different ways, reflecting SSH 2's
450 * altogether saner approach to port forwarding.
451 *
452 * In SSH 1, you arrange a remote forwarding by sending the server
453 * the remote port number, and the local destination host:port.
454 * When a connection comes in, the server sends you back that
455 * host:port pair, and you connect to it. This is a ready-made
456 * security hole if you're not on the ball: a malicious server
457 * could send you back _any_ host:port pair, so if you trustingly
458 * connect to the address it gives you then you've just opened the
459 * entire inside of your corporate network just by connecting
460 * through it to a dodgy SSH server. Hence, we must store a list of
461 * host:port pairs we _are_ trying to forward to, and reject a
462 * connection request from the server if it's not in the list.
463 *
464 * In SSH 2, each side of the connection minds its own business and
465 * doesn't send unnecessary information to the other. You arrange a
466 * remote forwarding by sending the server just the remote port
467 * number. When a connection comes in, the server tells you which
468 * of its ports was connected to; and _you_ have to remember what
469 * local host:port pair went with that port number.
470 *
471 * Hence: in SSH 1 this structure stores host:port pairs we intend
472 * to allow connections to, and is indexed by those host:port
473 * pairs. In SSH 2 it stores a mapping from source port to
474 * destination host:port pair, and is indexed by source port.
475 */
476 struct ssh_rportfwd {
477 unsigned sport, dport;
478 char dhost[256];
479 };
480
481 struct Packet {
482 long length;
483 int type;
484 unsigned char *data;
485 unsigned char *body;
486 long savedpos;
487 long maxlen;
488 };
489
490 static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt);
491 static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt);
492 static void ssh_size(void *handle, int width, int height);
493 static void ssh_special(void *handle, Telnet_Special);
494 static int ssh2_try_send(struct ssh_channel *c);
495 static void ssh2_add_channel_data(struct ssh_channel *c, char *buf, int len);
496 static void ssh_throttle_all(Ssh ssh, int enable, int bufsize);
497 static void ssh2_set_window(struct ssh_channel *c, unsigned newwin);
498 static int ssh_sendbuffer(void *handle);
499
500 struct rdpkt1_state_tag {
501 long len, pad, biglen, to_read;
502 unsigned long realcrc, gotcrc;
503 unsigned char *p;
504 int i;
505 int chunk;
506 };
507
508 struct rdpkt2_state_tag {
509 long len, pad, payload, packetlen, maclen;
510 int i;
511 int cipherblk;
512 unsigned long incoming_sequence;
513 };
514
515 struct ssh_tag {
516 const struct plug_function_table *fn;
517 /* the above field _must_ be first in the structure */
518
519 SHA_State exhash, exhashbase;
520
521 Socket s;
522
523 void *ldisc;
524 void *logctx;
525
526 unsigned char session_key[32];
527 int v1_compressing;
528 int v1_remote_protoflags;
529 int v1_local_protoflags;
530 int agentfwd_enabled;
531 int X11_fwd_enabled;
532 int remote_bugs;
533 const struct ssh_cipher *cipher;
534 void *v1_cipher_ctx;
535 void *crcda_ctx;
536 const struct ssh2_cipher *cscipher, *sccipher;
537 void *cs_cipher_ctx, *sc_cipher_ctx;
538 const struct ssh_mac *csmac, *scmac;
539 void *cs_mac_ctx, *sc_mac_ctx;
540 const struct ssh_compress *cscomp, *sccomp;
541 void *cs_comp_ctx, *sc_comp_ctx;
542 const struct ssh_kex *kex;
543 const struct ssh_signkey *hostkey;
544 unsigned char v2_session_id[20];
545 void *kex_ctx;
546
547 char *savedhost;
548 int savedport;
549 int send_ok;
550 int echoing, editing;
551
552 void *frontend;
553
554 int term_width, term_height;
555
556 tree234 *channels; /* indexed by local id */
557 struct ssh_channel *mainchan; /* primary session channel */
558 int exitcode;
559
560 tree234 *rportfwds;
561
562 enum {
563 SSH_STATE_PREPACKET,
564 SSH_STATE_BEFORE_SIZE,
565 SSH_STATE_INTERMED,
566 SSH_STATE_SESSION,
567 SSH_STATE_CLOSED
568 } state;
569
570 int size_needed, eof_needed;
571
572 struct Packet pktin;
573 struct Packet pktout;
574 unsigned char *deferred_send_data;
575 int deferred_len, deferred_size;
576
577 /*
578 * Gross hack: pscp will try to start SFTP but fall back to
579 * scp1 if that fails. This variable is the means by which
580 * scp.c can reach into the SSH code and find out which one it
581 * got.
582 */
583 int fallback_cmd;
584
585 /*
586 * Used for username and password input.
587 */
588 char *userpass_input_buffer;
589 int userpass_input_buflen;
590 int userpass_input_bufpos;
591 int userpass_input_echo;
592
593 char *portfwd_strptr;
594 int pkt_ctx;
595
596 void *x11auth;
597
598 int version;
599 int v1_throttle_count;
600 int overall_bufsize;
601 int throttled_all;
602 int v1_stdout_throttling;
603 int v2_outgoing_sequence;
604
605 int ssh1_rdpkt_crstate;
606 int ssh2_rdpkt_crstate;
607 int do_ssh_init_crstate;
608 int ssh_gotdata_crstate;
609 int ssh1_protocol_crstate;
610 int do_ssh1_login_crstate;
611 int do_ssh2_transport_crstate;
612 int do_ssh2_authconn_crstate;
613
614 void *do_ssh_init_state;
615 void *do_ssh1_login_state;
616 void *do_ssh2_transport_state;
617 void *do_ssh2_authconn_state;
618
619 struct rdpkt1_state_tag rdpkt1_state;
620 struct rdpkt2_state_tag rdpkt2_state;
621
622 void (*protocol) (Ssh ssh, unsigned char *in, int inlen, int ispkt);
623 int (*s_rdpkt) (Ssh ssh, unsigned char **data, int *datalen);
624
625 /*
626 * We maintain a full _copy_ of a Config structure here, not
627 * merely a pointer to it. That way, when we're passed a new
628 * one for reconfiguration, we can check the differences and
629 * potentially reconfigure port forwardings etc in mid-session.
630 */
631 Config cfg;
632 };
633
634 #define logevent(s) logevent(ssh->frontend, s)
635
636 /* logevent, only printf-formatted. */
637 static void logeventf(Ssh ssh, char *fmt, ...)
638 {
639 va_list ap;
640 char *buf;
641
642 va_start(ap, fmt);
643 buf = dupvprintf(fmt, ap);
644 va_end(ap);
645 logevent(buf);
646 sfree(buf);
647 }
648
649 #define bombout(msg) ( ssh->state = SSH_STATE_CLOSED, \
650 (ssh->s ? sk_close(ssh->s), ssh->s = NULL : 0), \
651 logeventf msg, connection_fatal msg )
652
653 static int ssh_channelcmp(void *av, void *bv)
654 {
655 struct ssh_channel *a = (struct ssh_channel *) av;
656 struct ssh_channel *b = (struct ssh_channel *) bv;
657 if (a->localid < b->localid)
658 return -1;
659 if (a->localid > b->localid)
660 return +1;
661 return 0;
662 }
663 static int ssh_channelfind(void *av, void *bv)
664 {
665 unsigned *a = (unsigned *) av;
666 struct ssh_channel *b = (struct ssh_channel *) bv;
667 if (*a < b->localid)
668 return -1;
669 if (*a > b->localid)
670 return +1;
671 return 0;
672 }
673
674 static int ssh_rportcmp_ssh1(void *av, void *bv)
675 {
676 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
677 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
678 int i;
679 if ( (i = strcmp(a->dhost, b->dhost)) != 0)
680 return i < 0 ? -1 : +1;
681 if (a->dport > b->dport)
682 return +1;
683 if (a->dport < b->dport)
684 return -1;
685 return 0;
686 }
687
688 static int ssh_rportcmp_ssh2(void *av, void *bv)
689 {
690 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
691 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
692
693 if (a->sport > b->sport)
694 return +1;
695 if (a->sport < b->sport)
696 return -1;
697 return 0;
698 }
699
700 static int alloc_channel_id(Ssh ssh)
701 {
702 const unsigned CHANNEL_NUMBER_OFFSET = 256;
703 unsigned low, high, mid;
704 int tsize;
705 struct ssh_channel *c;
706
707 /*
708 * First-fit allocation of channel numbers: always pick the
709 * lowest unused one. To do this, binary-search using the
710 * counted B-tree to find the largest channel ID which is in a
711 * contiguous sequence from the beginning. (Precisely
712 * everything in that sequence must have ID equal to its tree
713 * index plus CHANNEL_NUMBER_OFFSET.)
714 */
715 tsize = count234(ssh->channels);
716
717 low = -1;
718 high = tsize;
719 while (high - low > 1) {
720 mid = (high + low) / 2;
721 c = index234(ssh->channels, mid);
722 if (c->localid == mid + CHANNEL_NUMBER_OFFSET)
723 low = mid; /* this one is fine */
724 else
725 high = mid; /* this one is past it */
726 }
727 /*
728 * Now low points to either -1, or the tree index of the
729 * largest ID in the initial sequence.
730 */
731 {
732 unsigned i = low + 1 + CHANNEL_NUMBER_OFFSET;
733 assert(NULL == find234(ssh->channels, &i, ssh_channelfind));
734 }
735 return low + 1 + CHANNEL_NUMBER_OFFSET;
736 }
737
738 static void c_write(Ssh ssh, const char *buf, int len)
739 {
740 if ((flags & FLAG_STDERR)) {
741 int i;
742 for (i = 0; i < len; i++)
743 if (buf[i] != '\r')
744 fputc(buf[i], stderr);
745 return;
746 }
747 from_backend(ssh->frontend, 1, buf, len);
748 }
749
750 static void c_write_untrusted(Ssh ssh, const char *buf, int len)
751 {
752 int i;
753 for (i = 0; i < len; i++) {
754 if (buf[i] == '\n')
755 c_write(ssh, "\r\n", 2);
756 else if ((buf[i] & 0x60) || (buf[i] == '\r'))
757 c_write(ssh, buf + i, 1);
758 }
759 }
760
761 static void c_write_str(Ssh ssh, const char *buf)
762 {
763 c_write(ssh, buf, strlen(buf));
764 }
765
766 /*
767 * Collect incoming data in the incoming packet buffer.
768 * Decipher and verify the packet when it is completely read.
769 * Drop SSH1_MSG_DEBUG and SSH1_MSG_IGNORE packets.
770 * Update the *data and *datalen variables.
771 * Return the additional nr of bytes needed, or 0 when
772 * a complete packet is available.
773 */
774 static int ssh1_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
775 {
776 struct rdpkt1_state_tag *st = &ssh->rdpkt1_state;
777
778 crBegin(ssh->ssh1_rdpkt_crstate);
779
780 next_packet:
781
782 ssh->pktin.type = 0;
783 ssh->pktin.length = 0;
784
785 for (st->i = st->len = 0; st->i < 4; st->i++) {
786 while ((*datalen) == 0)
787 crReturn(4 - st->i);
788 st->len = (st->len << 8) + **data;
789 (*data)++, (*datalen)--;
790 }
791
792 st->pad = 8 - (st->len % 8);
793 st->biglen = st->len + st->pad;
794 ssh->pktin.length = st->len - 5;
795
796 if (ssh->pktin.maxlen < st->biglen) {
797 ssh->pktin.maxlen = st->biglen;
798 ssh->pktin.data = srealloc(ssh->pktin.data, st->biglen + APIEXTRA);
799 }
800
801 st->to_read = st->biglen;
802 st->p = ssh->pktin.data;
803 while (st->to_read > 0) {
804 st->chunk = st->to_read;
805 while ((*datalen) == 0)
806 crReturn(st->to_read);
807 if (st->chunk > (*datalen))
808 st->chunk = (*datalen);
809 memcpy(st->p, *data, st->chunk);
810 *data += st->chunk;
811 *datalen -= st->chunk;
812 st->p += st->chunk;
813 st->to_read -= st->chunk;
814 }
815
816 if (ssh->cipher && detect_attack(ssh->crcda_ctx, ssh->pktin.data,
817 st->biglen, NULL)) {
818 bombout((ssh,"Network attack (CRC compensation) detected!"));
819 crReturn(0);
820 }
821
822 if (ssh->cipher)
823 ssh->cipher->decrypt(ssh->v1_cipher_ctx, ssh->pktin.data, st->biglen);
824
825 st->realcrc = crc32(ssh->pktin.data, st->biglen - 4);
826 st->gotcrc = GET_32BIT(ssh->pktin.data + st->biglen - 4);
827 if (st->gotcrc != st->realcrc) {
828 bombout((ssh,"Incorrect CRC received on packet"));
829 crReturn(0);
830 }
831
832 ssh->pktin.body = ssh->pktin.data + st->pad + 1;
833
834 if (ssh->v1_compressing) {
835 unsigned char *decompblk;
836 int decomplen;
837 zlib_decompress_block(ssh->sc_comp_ctx,
838 ssh->pktin.body - 1, ssh->pktin.length + 1,
839 &decompblk, &decomplen);
840
841 if (ssh->pktin.maxlen < st->pad + decomplen) {
842 ssh->pktin.maxlen = st->pad + decomplen;
843 ssh->pktin.data = srealloc(ssh->pktin.data,
844 ssh->pktin.maxlen + APIEXTRA);
845 ssh->pktin.body = ssh->pktin.data + st->pad + 1;
846 }
847
848 memcpy(ssh->pktin.body - 1, decompblk, decomplen);
849 sfree(decompblk);
850 ssh->pktin.length = decomplen - 1;
851 }
852
853 ssh->pktin.type = ssh->pktin.body[-1];
854
855 if (ssh->logctx)
856 log_packet(ssh->logctx,
857 PKT_INCOMING, ssh->pktin.type,
858 ssh1_pkt_type(ssh->pktin.type),
859 ssh->pktin.body, ssh->pktin.length);
860
861 if (ssh->pktin.type == SSH1_SMSG_STDOUT_DATA ||
862 ssh->pktin.type == SSH1_SMSG_STDERR_DATA ||
863 ssh->pktin.type == SSH1_MSG_DEBUG ||
864 ssh->pktin.type == SSH1_SMSG_AUTH_TIS_CHALLENGE ||
865 ssh->pktin.type == SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
866 long stringlen = GET_32BIT(ssh->pktin.body);
867 if (stringlen + 4 != ssh->pktin.length) {
868 bombout((ssh,"Received data packet with bogus string length"));
869 crReturn(0);
870 }
871 }
872
873 if (ssh->pktin.type == SSH1_MSG_DEBUG) {
874 /* log debug message */
875 char buf[512];
876 int stringlen = GET_32BIT(ssh->pktin.body);
877 strcpy(buf, "Remote debug message: ");
878 if (stringlen > 480)
879 stringlen = 480;
880 memcpy(buf + 8, ssh->pktin.body + 4, stringlen);
881 buf[8 + stringlen] = '\0';
882 logevent(buf);
883 goto next_packet;
884 } else if (ssh->pktin.type == SSH1_MSG_IGNORE) {
885 /* do nothing */
886 goto next_packet;
887 }
888
889 if (ssh->pktin.type == SSH1_MSG_DISCONNECT) {
890 /* log reason code in disconnect message */
891 char buf[256];
892 unsigned msglen = GET_32BIT(ssh->pktin.body);
893 unsigned nowlen;
894 strcpy(buf, "Remote sent disconnect: ");
895 nowlen = strlen(buf);
896 if (msglen > sizeof(buf) - nowlen - 1)
897 msglen = sizeof(buf) - nowlen - 1;
898 memcpy(buf + nowlen, ssh->pktin.body + 4, msglen);
899 buf[nowlen + msglen] = '\0';
900 /* logevent(buf); (this is now done within the bombout macro) */
901 bombout((ssh,"Server sent disconnect message:\n\"%s\"", buf+nowlen));
902 crReturn(0);
903 }
904
905 crFinish(0);
906 }
907
908 static int ssh2_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
909 {
910 struct rdpkt2_state_tag *st = &ssh->rdpkt2_state;
911
912 crBegin(ssh->ssh2_rdpkt_crstate);
913
914 next_packet:
915 ssh->pktin.type = 0;
916 ssh->pktin.length = 0;
917 if (ssh->sccipher)
918 st->cipherblk = ssh->sccipher->blksize;
919 else
920 st->cipherblk = 8;
921 if (st->cipherblk < 8)
922 st->cipherblk = 8;
923
924 if (ssh->pktin.maxlen < st->cipherblk) {
925 ssh->pktin.maxlen = st->cipherblk;
926 ssh->pktin.data = srealloc(ssh->pktin.data, st->cipherblk + APIEXTRA);
927 }
928
929 /*
930 * Acquire and decrypt the first block of the packet. This will
931 * contain the length and padding details.
932 */
933 for (st->i = st->len = 0; st->i < st->cipherblk; st->i++) {
934 while ((*datalen) == 0)
935 crReturn(st->cipherblk - st->i);
936 ssh->pktin.data[st->i] = *(*data)++;
937 (*datalen)--;
938 }
939
940 if (ssh->sccipher)
941 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
942 ssh->pktin.data, st->cipherblk);
943
944 /*
945 * Now get the length and padding figures.
946 */
947 st->len = GET_32BIT(ssh->pktin.data);
948 st->pad = ssh->pktin.data[4];
949
950 /*
951 * _Completely_ silly lengths should be stomped on before they
952 * do us any more damage.
953 */
954 if (st->len < 0 || st->pad < 0 || st->len + st->pad < 0) {
955 bombout((ssh,"Incoming packet was garbled on decryption"));
956 crReturn(0);
957 }
958
959 /*
960 * This enables us to deduce the payload length.
961 */
962 st->payload = st->len - st->pad - 1;
963
964 ssh->pktin.length = st->payload + 5;
965
966 /*
967 * So now we can work out the total packet length.
968 */
969 st->packetlen = st->len + 4;
970 st->maclen = ssh->scmac ? ssh->scmac->len : 0;
971
972 /*
973 * Adjust memory allocation if packet is too big.
974 */
975 if (ssh->pktin.maxlen < st->packetlen + st->maclen) {
976 ssh->pktin.maxlen = st->packetlen + st->maclen;
977 ssh->pktin.data = srealloc(ssh->pktin.data,
978 ssh->pktin.maxlen + APIEXTRA);
979 }
980
981 /*
982 * Read and decrypt the remainder of the packet.
983 */
984 for (st->i = st->cipherblk; st->i < st->packetlen + st->maclen;
985 st->i++) {
986 while ((*datalen) == 0)
987 crReturn(st->packetlen + st->maclen - st->i);
988 ssh->pktin.data[st->i] = *(*data)++;
989 (*datalen)--;
990 }
991 /* Decrypt everything _except_ the MAC. */
992 if (ssh->sccipher)
993 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
994 ssh->pktin.data + st->cipherblk,
995 st->packetlen - st->cipherblk);
996
997 /*
998 * Check the MAC.
999 */
1000 if (ssh->scmac
1001 && !ssh->scmac->verify(ssh->sc_mac_ctx, ssh->pktin.data, st->len + 4,
1002 st->incoming_sequence)) {
1003 bombout((ssh,"Incorrect MAC received on packet"));
1004 crReturn(0);
1005 }
1006 st->incoming_sequence++; /* whether or not we MACed */
1007
1008 /*
1009 * Decompress packet payload.
1010 */
1011 {
1012 unsigned char *newpayload;
1013 int newlen;
1014 if (ssh->sccomp &&
1015 ssh->sccomp->decompress(ssh->sc_comp_ctx,
1016 ssh->pktin.data + 5, ssh->pktin.length - 5,
1017 &newpayload, &newlen)) {
1018 if (ssh->pktin.maxlen < newlen + 5) {
1019 ssh->pktin.maxlen = newlen + 5;
1020 ssh->pktin.data = srealloc(ssh->pktin.data,
1021 ssh->pktin.maxlen + APIEXTRA);
1022 }
1023 ssh->pktin.length = 5 + newlen;
1024 memcpy(ssh->pktin.data + 5, newpayload, newlen);
1025 sfree(newpayload);
1026 }
1027 }
1028
1029 ssh->pktin.savedpos = 6;
1030 ssh->pktin.type = ssh->pktin.data[5];
1031
1032 if (ssh->logctx)
1033 log_packet(ssh->logctx, PKT_INCOMING, ssh->pktin.type,
1034 ssh2_pkt_type(ssh->pkt_ctx, ssh->pktin.type),
1035 ssh->pktin.data+6, ssh->pktin.length-6);
1036
1037 switch (ssh->pktin.type) {
1038 /*
1039 * These packets we must handle instantly.
1040 */
1041 case SSH2_MSG_DISCONNECT:
1042 {
1043 /* log reason code in disconnect message */
1044 char *buf;
1045 int nowlen;
1046 int reason = GET_32BIT(ssh->pktin.data + 6);
1047 unsigned msglen = GET_32BIT(ssh->pktin.data + 10);
1048
1049 if (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) {
1050 buf = dupprintf("Received disconnect message (%s)",
1051 ssh2_disconnect_reasons[reason]);
1052 } else {
1053 buf = dupprintf("Received disconnect message (unknown"
1054 " type %d)", reason);
1055 }
1056 logevent(buf);
1057 sfree(buf);
1058 buf = dupprintf("Disconnection message text: %n%.*s",
1059 &nowlen, msglen, ssh->pktin.data + 14);
1060 logevent(buf);
1061 bombout((ssh,"Server sent disconnect message\ntype %d (%s):\n\"%s\"",
1062 reason,
1063 (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) ?
1064 ssh2_disconnect_reasons[reason] : "unknown",
1065 buf+nowlen));
1066 sfree(buf);
1067 crReturn(0);
1068 }
1069 break;
1070 case SSH2_MSG_IGNORE:
1071 goto next_packet;
1072 case SSH2_MSG_DEBUG:
1073 {
1074 /* log the debug message */
1075 char buf[512];
1076 /* int display = ssh->pktin.body[6]; */
1077 int stringlen = GET_32BIT(ssh->pktin.data+7);
1078 int prefix;
1079 strcpy(buf, "Remote debug message: ");
1080 prefix = strlen(buf);
1081 if (stringlen > (int)(sizeof(buf)-prefix-1))
1082 stringlen = sizeof(buf)-prefix-1;
1083 memcpy(buf + prefix, ssh->pktin.data + 11, stringlen);
1084 buf[prefix + stringlen] = '\0';
1085 logevent(buf);
1086 }
1087 goto next_packet; /* FIXME: print the debug message */
1088
1089 /*
1090 * These packets we need do nothing about here.
1091 */
1092 case SSH2_MSG_UNIMPLEMENTED:
1093 case SSH2_MSG_SERVICE_REQUEST:
1094 case SSH2_MSG_SERVICE_ACCEPT:
1095 case SSH2_MSG_KEXINIT:
1096 case SSH2_MSG_NEWKEYS:
1097 case SSH2_MSG_KEXDH_INIT:
1098 case SSH2_MSG_KEXDH_REPLY:
1099 /* case SSH2_MSG_KEX_DH_GEX_REQUEST: duplicate case value */
1100 /* case SSH2_MSG_KEX_DH_GEX_GROUP: duplicate case value */
1101 case SSH2_MSG_KEX_DH_GEX_INIT:
1102 case SSH2_MSG_KEX_DH_GEX_REPLY:
1103 case SSH2_MSG_USERAUTH_REQUEST:
1104 case SSH2_MSG_USERAUTH_FAILURE:
1105 case SSH2_MSG_USERAUTH_SUCCESS:
1106 case SSH2_MSG_USERAUTH_BANNER:
1107 case SSH2_MSG_USERAUTH_PK_OK:
1108 /* case SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ: duplicate case value */
1109 /* case SSH2_MSG_USERAUTH_INFO_REQUEST: duplicate case value */
1110 case SSH2_MSG_USERAUTH_INFO_RESPONSE:
1111 case SSH2_MSG_GLOBAL_REQUEST:
1112 case SSH2_MSG_REQUEST_SUCCESS:
1113 case SSH2_MSG_REQUEST_FAILURE:
1114 case SSH2_MSG_CHANNEL_OPEN:
1115 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION:
1116 case SSH2_MSG_CHANNEL_OPEN_FAILURE:
1117 case SSH2_MSG_CHANNEL_WINDOW_ADJUST:
1118 case SSH2_MSG_CHANNEL_DATA:
1119 case SSH2_MSG_CHANNEL_EXTENDED_DATA:
1120 case SSH2_MSG_CHANNEL_EOF:
1121 case SSH2_MSG_CHANNEL_CLOSE:
1122 case SSH2_MSG_CHANNEL_REQUEST:
1123 case SSH2_MSG_CHANNEL_SUCCESS:
1124 case SSH2_MSG_CHANNEL_FAILURE:
1125 break;
1126
1127 /*
1128 * For anything else we send SSH2_MSG_UNIMPLEMENTED.
1129 */
1130 default:
1131 ssh2_pkt_init(ssh, SSH2_MSG_UNIMPLEMENTED);
1132 ssh2_pkt_adduint32(ssh, st->incoming_sequence - 1);
1133 ssh2_pkt_send(ssh);
1134 break;
1135 }
1136
1137 crFinish(0);
1138 }
1139
1140 static void ssh1_pktout_size(Ssh ssh, int len)
1141 {
1142 int pad, biglen;
1143
1144 len += 5; /* type and CRC */
1145 pad = 8 - (len % 8);
1146 biglen = len + pad;
1147
1148 ssh->pktout.length = len - 5;
1149 if (ssh->pktout.maxlen < biglen) {
1150 ssh->pktout.maxlen = biglen;
1151 #ifdef MSCRYPTOAPI
1152 /* Allocate enough buffer space for extra block
1153 * for MS CryptEncrypt() */
1154 ssh->pktout.data = srealloc(ssh->pktout.data, biglen + 12);
1155 #else
1156 ssh->pktout.data = srealloc(ssh->pktout.data, biglen + 4);
1157 #endif
1158 }
1159 ssh->pktout.body = ssh->pktout.data + 4 + pad + 1;
1160 }
1161
1162 static void s_wrpkt_start(Ssh ssh, int type, int len)
1163 {
1164 ssh1_pktout_size(ssh, len);
1165 ssh->pktout.type = type;
1166 }
1167
1168 static int s_wrpkt_prepare(Ssh ssh)
1169 {
1170 int pad, biglen, i;
1171 unsigned long crc;
1172 #ifdef __SC__
1173 /*
1174 * XXX various versions of SC (including 8.8.4) screw up the
1175 * register allocation in this function and use the same register
1176 * (D6) for len and as a temporary, with predictable results. The
1177 * following sledgehammer prevents this.
1178 */
1179 volatile
1180 #endif
1181 int len;
1182
1183 ssh->pktout.body[-1] = ssh->pktout.type;
1184
1185 if (ssh->logctx)
1186 log_packet(ssh->logctx, PKT_OUTGOING, ssh->pktout.type,
1187 ssh1_pkt_type(ssh->pktout.type),
1188 ssh->pktout.body, ssh->pktout.length);
1189
1190 if (ssh->v1_compressing) {
1191 unsigned char *compblk;
1192 int complen;
1193 zlib_compress_block(ssh->cs_comp_ctx,
1194 ssh->pktout.body - 1, ssh->pktout.length + 1,
1195 &compblk, &complen);
1196 ssh1_pktout_size(ssh, complen - 1);
1197 memcpy(ssh->pktout.body - 1, compblk, complen);
1198 sfree(compblk);
1199 }
1200
1201 len = ssh->pktout.length + 5; /* type and CRC */
1202 pad = 8 - (len % 8);
1203 biglen = len + pad;
1204
1205 for (i = 0; i < pad; i++)
1206 ssh->pktout.data[i + 4] = random_byte();
1207 crc = crc32(ssh->pktout.data + 4, biglen - 4);
1208 PUT_32BIT(ssh->pktout.data + biglen, crc);
1209 PUT_32BIT(ssh->pktout.data, len);
1210
1211 if (ssh->cipher)
1212 ssh->cipher->encrypt(ssh->v1_cipher_ctx, ssh->pktout.data + 4, biglen);
1213
1214 return biglen + 4;
1215 }
1216
1217 static void s_wrpkt(Ssh ssh)
1218 {
1219 int len, backlog;
1220 len = s_wrpkt_prepare(ssh);
1221 backlog = sk_write(ssh->s, (char *)ssh->pktout.data, len);
1222 if (backlog > SSH_MAX_BACKLOG)
1223 ssh_throttle_all(ssh, 1, backlog);
1224 }
1225
1226 static void s_wrpkt_defer(Ssh ssh)
1227 {
1228 int len;
1229 len = s_wrpkt_prepare(ssh);
1230 if (ssh->deferred_len + len > ssh->deferred_size) {
1231 ssh->deferred_size = ssh->deferred_len + len + 128;
1232 ssh->deferred_send_data = srealloc(ssh->deferred_send_data,
1233 ssh->deferred_size);
1234 }
1235 memcpy(ssh->deferred_send_data + ssh->deferred_len, ssh->pktout.data, len);
1236 ssh->deferred_len += len;
1237 }
1238
1239 /*
1240 * Construct a packet with the specified contents.
1241 */
1242 static void construct_packet(Ssh ssh, int pkttype, va_list ap1, va_list ap2)
1243 {
1244 unsigned char *p, *argp, argchar;
1245 unsigned long argint;
1246 int pktlen, argtype, arglen;
1247 Bignum bn;
1248
1249 pktlen = 0;
1250 while ((argtype = va_arg(ap1, int)) != PKT_END) {
1251 switch (argtype) {
1252 case PKT_INT:
1253 (void) va_arg(ap1, int);
1254 pktlen += 4;
1255 break;
1256 case PKT_CHAR:
1257 (void) va_arg(ap1, int);
1258 pktlen++;
1259 break;
1260 case PKT_DATA:
1261 (void) va_arg(ap1, unsigned char *);
1262 arglen = va_arg(ap1, int);
1263 pktlen += arglen;
1264 break;
1265 case PKT_STR:
1266 argp = va_arg(ap1, unsigned char *);
1267 arglen = strlen((char *)argp);
1268 pktlen += 4 + arglen;
1269 break;
1270 case PKT_BIGNUM:
1271 bn = va_arg(ap1, Bignum);
1272 pktlen += ssh1_bignum_length(bn);
1273 break;
1274 default:
1275 assert(0);
1276 }
1277 }
1278
1279 s_wrpkt_start(ssh, pkttype, pktlen);
1280 p = ssh->pktout.body;
1281
1282 while ((argtype = va_arg(ap2, int)) != PKT_END) {
1283 switch (argtype) {
1284 case PKT_INT:
1285 argint = va_arg(ap2, int);
1286 PUT_32BIT(p, argint);
1287 p += 4;
1288 break;
1289 case PKT_CHAR:
1290 argchar = (unsigned char) va_arg(ap2, int);
1291 *p = argchar;
1292 p++;
1293 break;
1294 case PKT_DATA:
1295 argp = va_arg(ap2, unsigned char *);
1296 arglen = va_arg(ap2, int);
1297 memcpy(p, argp, arglen);
1298 p += arglen;
1299 break;
1300 case PKT_STR:
1301 argp = va_arg(ap2, unsigned char *);
1302 arglen = strlen((char *)argp);
1303 PUT_32BIT(p, arglen);
1304 memcpy(p + 4, argp, arglen);
1305 p += 4 + arglen;
1306 break;
1307 case PKT_BIGNUM:
1308 bn = va_arg(ap2, Bignum);
1309 p += ssh1_write_bignum(p, bn);
1310 break;
1311 }
1312 }
1313 }
1314
1315 static void send_packet(Ssh ssh, int pkttype, ...)
1316 {
1317 va_list ap1, ap2;
1318 va_start(ap1, pkttype);
1319 va_start(ap2, pkttype);
1320 construct_packet(ssh, pkttype, ap1, ap2);
1321 s_wrpkt(ssh);
1322 }
1323
1324 static void defer_packet(Ssh ssh, int pkttype, ...)
1325 {
1326 va_list ap1, ap2;
1327 va_start(ap1, pkttype);
1328 va_start(ap2, pkttype);
1329 construct_packet(ssh, pkttype, ap1, ap2);
1330 s_wrpkt_defer(ssh);
1331 }
1332
1333 static int ssh_versioncmp(char *a, char *b)
1334 {
1335 char *ae, *be;
1336 unsigned long av, bv;
1337
1338 av = strtoul(a, &ae, 10);
1339 bv = strtoul(b, &be, 10);
1340 if (av != bv)
1341 return (av < bv ? -1 : +1);
1342 if (*ae == '.')
1343 ae++;
1344 if (*be == '.')
1345 be++;
1346 av = strtoul(ae, &ae, 10);
1347 bv = strtoul(be, &be, 10);
1348 if (av != bv)
1349 return (av < bv ? -1 : +1);
1350 return 0;
1351 }
1352
1353 /*
1354 * Utility routines for putting an SSH-protocol `string' and
1355 * `uint32' into a SHA state.
1356 */
1357 #include <stdio.h>
1358 static void sha_string(SHA_State * s, void *str, int len)
1359 {
1360 unsigned char lenblk[4];
1361 PUT_32BIT(lenblk, len);
1362 SHA_Bytes(s, lenblk, 4);
1363 SHA_Bytes(s, str, len);
1364 }
1365
1366 static void sha_uint32(SHA_State * s, unsigned i)
1367 {
1368 unsigned char intblk[4];
1369 PUT_32BIT(intblk, i);
1370 SHA_Bytes(s, intblk, 4);
1371 }
1372
1373 /*
1374 * SSH2 packet construction functions.
1375 */
1376 static void ssh2_pkt_ensure(Ssh ssh, int length)
1377 {
1378 if (ssh->pktout.maxlen < length) {
1379 ssh->pktout.maxlen = length + 256;
1380 ssh->pktout.data = srealloc(ssh->pktout.data,
1381 ssh->pktout.maxlen + APIEXTRA);
1382 if (!ssh->pktout.data)
1383 fatalbox("Out of memory");
1384 }
1385 }
1386 static void ssh2_pkt_adddata(Ssh ssh, void *data, int len)
1387 {
1388 ssh->pktout.length += len;
1389 ssh2_pkt_ensure(ssh, ssh->pktout.length);
1390 memcpy(ssh->pktout.data + ssh->pktout.length - len, data, len);
1391 }
1392 static void ssh2_pkt_addbyte(Ssh ssh, unsigned char byte)
1393 {
1394 ssh2_pkt_adddata(ssh, &byte, 1);
1395 }
1396 static void ssh2_pkt_init(Ssh ssh, int pkt_type)
1397 {
1398 ssh->pktout.length = 5;
1399 ssh2_pkt_addbyte(ssh, (unsigned char) pkt_type);
1400 }
1401 static void ssh2_pkt_addbool(Ssh ssh, unsigned char value)
1402 {
1403 ssh2_pkt_adddata(ssh, &value, 1);
1404 }
1405 static void ssh2_pkt_adduint32(Ssh ssh, unsigned long value)
1406 {
1407 unsigned char x[4];
1408 PUT_32BIT(x, value);
1409 ssh2_pkt_adddata(ssh, x, 4);
1410 }
1411 static void ssh2_pkt_addstring_start(Ssh ssh)
1412 {
1413 ssh2_pkt_adduint32(ssh, 0);
1414 ssh->pktout.savedpos = ssh->pktout.length;
1415 }
1416 static void ssh2_pkt_addstring_str(Ssh ssh, char *data)
1417 {
1418 ssh2_pkt_adddata(ssh, data, strlen(data));
1419 PUT_32BIT(ssh->pktout.data + ssh->pktout.savedpos - 4,
1420 ssh->pktout.length - ssh->pktout.savedpos);
1421 }
1422 static void ssh2_pkt_addstring_data(Ssh ssh, char *data, int len)
1423 {
1424 ssh2_pkt_adddata(ssh, data, len);
1425 PUT_32BIT(ssh->pktout.data + ssh->pktout.savedpos - 4,
1426 ssh->pktout.length - ssh->pktout.savedpos);
1427 }
1428 static void ssh2_pkt_addstring(Ssh ssh, char *data)
1429 {
1430 ssh2_pkt_addstring_start(ssh);
1431 ssh2_pkt_addstring_str(ssh, data);
1432 }
1433 static unsigned char *ssh2_mpint_fmt(Bignum b, int *len)
1434 {
1435 unsigned char *p;
1436 int i, n = (bignum_bitcount(b) + 7) / 8;
1437 p = smalloc(n + 1);
1438 if (!p)
1439 fatalbox("out of memory");
1440 p[0] = 0;
1441 for (i = 1; i <= n; i++)
1442 p[i] = bignum_byte(b, n - i);
1443 i = 0;
1444 while (i <= n && p[i] == 0 && (p[i + 1] & 0x80) == 0)
1445 i++;
1446 memmove(p, p + i, n + 1 - i);
1447 *len = n + 1 - i;
1448 return p;
1449 }
1450 static void ssh2_pkt_addmp(Ssh ssh, Bignum b)
1451 {
1452 unsigned char *p;
1453 int len;
1454 p = ssh2_mpint_fmt(b, &len);
1455 ssh2_pkt_addstring_start(ssh);
1456 ssh2_pkt_addstring_data(ssh, (char *)p, len);
1457 sfree(p);
1458 }
1459
1460 /*
1461 * Construct an SSH2 final-form packet: compress it, encrypt it,
1462 * put the MAC on it. Final packet, ready to be sent, is stored in
1463 * ssh->pktout.data. Total length is returned.
1464 */
1465 static int ssh2_pkt_construct(Ssh ssh)
1466 {
1467 int cipherblk, maclen, padding, i;
1468
1469 if (ssh->logctx)
1470 log_packet(ssh->logctx, PKT_OUTGOING, ssh->pktout.data[5],
1471 ssh2_pkt_type(ssh->pkt_ctx, ssh->pktout.data[5]),
1472 ssh->pktout.data + 6, ssh->pktout.length - 6);
1473
1474 /*
1475 * Compress packet payload.
1476 */
1477 {
1478 unsigned char *newpayload;
1479 int newlen;
1480 if (ssh->cscomp &&
1481 ssh->cscomp->compress(ssh->cs_comp_ctx, ssh->pktout.data + 5,
1482 ssh->pktout.length - 5,
1483 &newpayload, &newlen)) {
1484 ssh->pktout.length = 5;
1485 ssh2_pkt_adddata(ssh, newpayload, newlen);
1486 sfree(newpayload);
1487 }
1488 }
1489
1490 /*
1491 * Add padding. At least four bytes, and must also bring total
1492 * length (minus MAC) up to a multiple of the block size.
1493 */
1494 cipherblk = ssh->cscipher ? ssh->cscipher->blksize : 8; /* block size */
1495 cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */
1496 padding = 4;
1497 padding +=
1498 (cipherblk - (ssh->pktout.length + padding) % cipherblk) % cipherblk;
1499 maclen = ssh->csmac ? ssh->csmac->len : 0;
1500 ssh2_pkt_ensure(ssh, ssh->pktout.length + padding + maclen);
1501 ssh->pktout.data[4] = padding;
1502 for (i = 0; i < padding; i++)
1503 ssh->pktout.data[ssh->pktout.length + i] = random_byte();
1504 PUT_32BIT(ssh->pktout.data, ssh->pktout.length + padding - 4);
1505 if (ssh->csmac)
1506 ssh->csmac->generate(ssh->cs_mac_ctx, ssh->pktout.data,
1507 ssh->pktout.length + padding,
1508 ssh->v2_outgoing_sequence);
1509 ssh->v2_outgoing_sequence++; /* whether or not we MACed */
1510
1511 if (ssh->cscipher)
1512 ssh->cscipher->encrypt(ssh->cs_cipher_ctx,
1513 ssh->pktout.data, ssh->pktout.length + padding);
1514
1515 /* Ready-to-send packet starts at ssh->pktout.data. We return length. */
1516 return ssh->pktout.length + padding + maclen;
1517 }
1518
1519 /*
1520 * Construct and send an SSH2 packet immediately.
1521 */
1522 static void ssh2_pkt_send(Ssh ssh)
1523 {
1524 int len;
1525 int backlog;
1526 len = ssh2_pkt_construct(ssh);
1527 backlog = sk_write(ssh->s, (char *)ssh->pktout.data, len);
1528 if (backlog > SSH_MAX_BACKLOG)
1529 ssh_throttle_all(ssh, 1, backlog);
1530 }
1531
1532 /*
1533 * Construct an SSH2 packet and add it to a deferred data block.
1534 * Useful for sending multiple packets in a single sk_write() call,
1535 * to prevent a traffic-analysing listener from being able to work
1536 * out the length of any particular packet (such as the password
1537 * packet).
1538 *
1539 * Note that because SSH2 sequence-numbers its packets, this can
1540 * NOT be used as an m4-style `defer' allowing packets to be
1541 * constructed in one order and sent in another.
1542 */
1543 static void ssh2_pkt_defer(Ssh ssh)
1544 {
1545 int len = ssh2_pkt_construct(ssh);
1546 if (ssh->deferred_len + len > ssh->deferred_size) {
1547 ssh->deferred_size = ssh->deferred_len + len + 128;
1548 ssh->deferred_send_data = srealloc(ssh->deferred_send_data,
1549 ssh->deferred_size);
1550 }
1551 memcpy(ssh->deferred_send_data + ssh->deferred_len, ssh->pktout.data, len);
1552 ssh->deferred_len += len;
1553 }
1554
1555 /*
1556 * Send the whole deferred data block constructed by
1557 * ssh2_pkt_defer() or SSH1's defer_packet().
1558 */
1559 static void ssh_pkt_defersend(Ssh ssh)
1560 {
1561 int backlog;
1562 backlog = sk_write(ssh->s, (char *)ssh->deferred_send_data,
1563 ssh->deferred_len);
1564 ssh->deferred_len = ssh->deferred_size = 0;
1565 sfree(ssh->deferred_send_data);
1566 ssh->deferred_send_data = NULL;
1567 if (backlog > SSH_MAX_BACKLOG)
1568 ssh_throttle_all(ssh, 1, backlog);
1569 }
1570
1571 #if 0
1572 void bndebug(char *string, Bignum b)
1573 {
1574 unsigned char *p;
1575 int i, len;
1576 p = ssh2_mpint_fmt(b, &len);
1577 debug(("%s", string));
1578 for (i = 0; i < len; i++)
1579 debug((" %02x", p[i]));
1580 debug(("\n"));
1581 sfree(p);
1582 }
1583 #endif
1584
1585 static void sha_mpint(SHA_State * s, Bignum b)
1586 {
1587 unsigned char *p;
1588 int len;
1589 p = ssh2_mpint_fmt(b, &len);
1590 sha_string(s, p, len);
1591 sfree(p);
1592 }
1593
1594 /*
1595 * SSH2 packet decode functions.
1596 */
1597 static unsigned long ssh2_pkt_getuint32(Ssh ssh)
1598 {
1599 unsigned long value;
1600 if (ssh->pktin.length - ssh->pktin.savedpos < 4)
1601 return 0; /* arrgh, no way to decline (FIXME?) */
1602 value = GET_32BIT(ssh->pktin.data + ssh->pktin.savedpos);
1603 ssh->pktin.savedpos += 4;
1604 return value;
1605 }
1606 static int ssh2_pkt_getbool(Ssh ssh)
1607 {
1608 unsigned long value;
1609 if (ssh->pktin.length - ssh->pktin.savedpos < 1)
1610 return 0; /* arrgh, no way to decline (FIXME?) */
1611 value = ssh->pktin.data[ssh->pktin.savedpos] != 0;
1612 ssh->pktin.savedpos++;
1613 return value;
1614 }
1615 static void ssh2_pkt_getstring(Ssh ssh, char **p, int *length)
1616 {
1617 int len;
1618 *p = NULL;
1619 *length = 0;
1620 if (ssh->pktin.length - ssh->pktin.savedpos < 4)
1621 return;
1622 len = GET_32BIT(ssh->pktin.data + ssh->pktin.savedpos);
1623 if (len < 0)
1624 return;
1625 *length = len;
1626 ssh->pktin.savedpos += 4;
1627 if (ssh->pktin.length - ssh->pktin.savedpos < *length)
1628 return;
1629 *p = (char *)(ssh->pktin.data + ssh->pktin.savedpos);
1630 ssh->pktin.savedpos += *length;
1631 }
1632 static Bignum ssh2_pkt_getmp(Ssh ssh)
1633 {
1634 char *p;
1635 int length;
1636 Bignum b;
1637
1638 ssh2_pkt_getstring(ssh, &p, &length);
1639 if (!p)
1640 return NULL;
1641 if (p[0] & 0x80) {
1642 bombout((ssh,"internal error: Can't handle negative mpints"));
1643 return NULL;
1644 }
1645 b = bignum_from_bytes((unsigned char *)p, length);
1646 return b;
1647 }
1648
1649 /*
1650 * Helper function to add an SSH2 signature blob to a packet.
1651 * Expects to be shown the public key blob as well as the signature
1652 * blob. Normally works just like ssh2_pkt_addstring, but will
1653 * fiddle with the signature packet if necessary for
1654 * BUG_SSH2_RSA_PADDING.
1655 */
1656 static void ssh2_add_sigblob(Ssh ssh, void *pkblob_v, int pkblob_len,
1657 void *sigblob_v, int sigblob_len)
1658 {
1659 unsigned char *pkblob = (unsigned char *)pkblob_v;
1660 unsigned char *sigblob = (unsigned char *)sigblob_v;
1661
1662 /* dmemdump(pkblob, pkblob_len); */
1663 /* dmemdump(sigblob, sigblob_len); */
1664
1665 /*
1666 * See if this is in fact an ssh-rsa signature and a buggy
1667 * server; otherwise we can just do this the easy way.
1668 */
1669 if ((ssh->remote_bugs & BUG_SSH2_RSA_PADDING) &&
1670 (GET_32BIT(pkblob) == 7 && !memcmp(pkblob+4, "ssh-rsa", 7))) {
1671 int pos, len, siglen;
1672
1673 /*
1674 * Find the byte length of the modulus.
1675 */
1676
1677 pos = 4+7; /* skip over "ssh-rsa" */
1678 pos += 4 + GET_32BIT(pkblob+pos); /* skip over exponent */
1679 len = GET_32BIT(pkblob+pos); /* find length of modulus */
1680 pos += 4; /* find modulus itself */
1681 while (len > 0 && pkblob[pos] == 0)
1682 len--, pos++;
1683 /* debug(("modulus length is %d\n", len)); */
1684
1685 /*
1686 * Now find the signature integer.
1687 */
1688 pos = 4+7; /* skip over "ssh-rsa" */
1689 siglen = GET_32BIT(sigblob+pos);
1690 /* debug(("signature length is %d\n", siglen)); */
1691
1692 if (len != siglen) {
1693 unsigned char newlen[4];
1694 ssh2_pkt_addstring_start(ssh);
1695 ssh2_pkt_addstring_data(ssh, (char *)sigblob, pos);
1696 /* dmemdump(sigblob, pos); */
1697 pos += 4; /* point to start of actual sig */
1698 PUT_32BIT(newlen, len);
1699 ssh2_pkt_addstring_data(ssh, (char *)newlen, 4);
1700 /* dmemdump(newlen, 4); */
1701 newlen[0] = 0;
1702 while (len-- > siglen) {
1703 ssh2_pkt_addstring_data(ssh, (char *)newlen, 1);
1704 /* dmemdump(newlen, 1); */
1705 }
1706 ssh2_pkt_addstring_data(ssh, (char *)(sigblob+pos), siglen);
1707 /* dmemdump(sigblob+pos, siglen); */
1708 return;
1709 }
1710
1711 /* Otherwise fall through and do it the easy way. */
1712 }
1713
1714 ssh2_pkt_addstring_start(ssh);
1715 ssh2_pkt_addstring_data(ssh, (char *)sigblob, sigblob_len);
1716 }
1717
1718 /*
1719 * Examine the remote side's version string and compare it against
1720 * a list of known buggy implementations.
1721 */
1722 static void ssh_detect_bugs(Ssh ssh, char *vstring)
1723 {
1724 char *imp; /* pointer to implementation part */
1725 imp = vstring;
1726 imp += strcspn(imp, "-");
1727 if (*imp) imp++;
1728 imp += strcspn(imp, "-");
1729 if (*imp) imp++;
1730
1731 ssh->remote_bugs = 0;
1732
1733 if (ssh->cfg.sshbug_ignore1 == FORCE_ON ||
1734 (ssh->cfg.sshbug_ignore1 == AUTO &&
1735 (!strcmp(imp, "1.2.18") || !strcmp(imp, "1.2.19") ||
1736 !strcmp(imp, "1.2.20") || !strcmp(imp, "1.2.21") ||
1737 !strcmp(imp, "1.2.22") || !strcmp(imp, "Cisco-1.25")))) {
1738 /*
1739 * These versions don't support SSH1_MSG_IGNORE, so we have
1740 * to use a different defence against password length
1741 * sniffing.
1742 */
1743 ssh->remote_bugs |= BUG_CHOKES_ON_SSH1_IGNORE;
1744 logevent("We believe remote version has SSH1 ignore bug");
1745 }
1746
1747 if (ssh->cfg.sshbug_plainpw1 == FORCE_ON ||
1748 (ssh->cfg.sshbug_plainpw1 == AUTO &&
1749 (!strcmp(imp, "Cisco-1.25")))) {
1750 /*
1751 * These versions need a plain password sent; they can't
1752 * handle having a null and a random length of data after
1753 * the password.
1754 */
1755 ssh->remote_bugs |= BUG_NEEDS_SSH1_PLAIN_PASSWORD;
1756 logevent("We believe remote version needs a plain SSH1 password");
1757 }
1758
1759 if (ssh->cfg.sshbug_rsa1 == FORCE_ON ||
1760 (ssh->cfg.sshbug_rsa1 == AUTO &&
1761 (!strcmp(imp, "Cisco-1.25")))) {
1762 /*
1763 * These versions apparently have no clue whatever about
1764 * RSA authentication and will panic and die if they see
1765 * an AUTH_RSA message.
1766 */
1767 ssh->remote_bugs |= BUG_CHOKES_ON_RSA;
1768 logevent("We believe remote version can't handle RSA authentication");
1769 }
1770
1771 if (ssh->cfg.sshbug_hmac2 == FORCE_ON ||
1772 (ssh->cfg.sshbug_hmac2 == AUTO &&
1773 (wc_match("2.1.0*", imp) || wc_match("2.0.*", imp) ||
1774 wc_match("2.2.0*", imp) || wc_match("2.3.0*", imp) ||
1775 wc_match("2.1 *", imp)))) {
1776 /*
1777 * These versions have the HMAC bug.
1778 */
1779 ssh->remote_bugs |= BUG_SSH2_HMAC;
1780 logevent("We believe remote version has SSH2 HMAC bug");
1781 }
1782
1783 if (ssh->cfg.sshbug_derivekey2 == FORCE_ON ||
1784 (ssh->cfg.sshbug_derivekey2 == AUTO &&
1785 (wc_match("2.0.0*", imp) || wc_match("2.0.10*", imp) ))) {
1786 /*
1787 * These versions have the key-derivation bug (failing to
1788 * include the literal shared secret in the hashes that
1789 * generate the keys).
1790 */
1791 ssh->remote_bugs |= BUG_SSH2_DERIVEKEY;
1792 logevent("We believe remote version has SSH2 key-derivation bug");
1793 }
1794
1795 if (ssh->cfg.sshbug_rsapad2 == FORCE_ON ||
1796 (ssh->cfg.sshbug_rsapad2 == AUTO &&
1797 (wc_match("OpenSSH_2.[5-9]*", imp) ||
1798 wc_match("OpenSSH_3.[0-2]*", imp)))) {
1799 /*
1800 * These versions have the SSH2 RSA padding bug.
1801 */
1802 ssh->remote_bugs |= BUG_SSH2_RSA_PADDING;
1803 logevent("We believe remote version has SSH2 RSA padding bug");
1804 }
1805
1806 if (ssh->cfg.sshbug_pksessid2 == FORCE_ON ||
1807 (ssh->cfg.sshbug_pksessid2 == AUTO &&
1808 wc_match("OpenSSH_2.[0-2]*", imp))) {
1809 /*
1810 * These versions have the SSH2 session-ID bug in
1811 * public-key authentication.
1812 */
1813 ssh->remote_bugs |= BUG_SSH2_PK_SESSIONID;
1814 logevent("We believe remote version has SSH2 public-key-session-ID bug");
1815 }
1816
1817 if (ssh->cfg.sshbug_dhgex2 == FORCE_ON) {
1818 /*
1819 * User specified the SSH2 DH GEX bug.
1820 */
1821 ssh->remote_bugs |= BUG_SSH2_DH_GEX;
1822 logevent("We believe remote version has SSH2 DH group exchange bug");
1823 }
1824 }
1825
1826 static int do_ssh_init(Ssh ssh, unsigned char c)
1827 {
1828 struct do_ssh_init_state {
1829 int vslen;
1830 char version[10];
1831 char *vstring;
1832 int vstrsize;
1833 int i;
1834 int proto1, proto2;
1835 };
1836 crState(do_ssh_init_state);
1837
1838 crBegin(ssh->do_ssh_init_crstate);
1839
1840 /* Search for the string "SSH-" in the input. */
1841 s->i = 0;
1842 while (1) {
1843 static const int transS[] = { 1, 2, 2, 1 };
1844 static const int transH[] = { 0, 0, 3, 0 };
1845 static const int transminus[] = { 0, 0, 0, -1 };
1846 if (c == 'S')
1847 s->i = transS[s->i];
1848 else if (c == 'H')
1849 s->i = transH[s->i];
1850 else if (c == '-')
1851 s->i = transminus[s->i];
1852 else
1853 s->i = 0;
1854 if (s->i < 0)
1855 break;
1856 crReturn(1); /* get another character */
1857 }
1858
1859 s->vstrsize = 16;
1860 s->vstring = smalloc(s->vstrsize);
1861 strcpy(s->vstring, "SSH-");
1862 s->vslen = 4;
1863 s->i = 0;
1864 while (1) {
1865 crReturn(1); /* get another char */
1866 if (s->vslen >= s->vstrsize - 1) {
1867 s->vstrsize += 16;
1868 s->vstring = srealloc(s->vstring, s->vstrsize);
1869 }
1870 s->vstring[s->vslen++] = c;
1871 if (s->i >= 0) {
1872 if (c == '-') {
1873 s->version[s->i] = '\0';
1874 s->i = -1;
1875 } else if (s->i < sizeof(s->version) - 1)
1876 s->version[s->i++] = c;
1877 } else if (c == '\012')
1878 break;
1879 }
1880
1881 ssh->agentfwd_enabled = FALSE;
1882 ssh->rdpkt2_state.incoming_sequence = 0;
1883
1884 s->vstring[s->vslen] = 0;
1885 s->vstring[strcspn(s->vstring, "\r\n")] = '\0';/* remove EOL chars */
1886 {
1887 char *vlog;
1888 vlog = smalloc(20 + s->vslen);
1889 sprintf(vlog, "Server version: %s", s->vstring);
1890 logevent(vlog);
1891 sfree(vlog);
1892 }
1893 ssh_detect_bugs(ssh, s->vstring);
1894
1895 /*
1896 * Decide which SSH protocol version to support.
1897 */
1898
1899 /* Anything strictly below "2.0" means protocol 1 is supported. */
1900 s->proto1 = ssh_versioncmp(s->version, "2.0") < 0;
1901 /* Anything greater or equal to "1.99" means protocol 2 is supported. */
1902 s->proto2 = ssh_versioncmp(s->version, "1.99") >= 0;
1903
1904 if (ssh->cfg.sshprot == 0 && !s->proto1) {
1905 bombout((ssh,"SSH protocol version 1 required by user but not provided by server"));
1906 crReturn(0);
1907 }
1908 if (ssh->cfg.sshprot == 3 && !s->proto2) {
1909 bombout((ssh,"SSH protocol version 2 required by user but not provided by server"));
1910 crReturn(0);
1911 }
1912
1913 if (s->proto2 && (ssh->cfg.sshprot >= 2 || !s->proto1)) {
1914 /*
1915 * Use v2 protocol.
1916 */
1917 char verstring[80], vlog[100];
1918 sprintf(verstring, "SSH-2.0-%s", sshver);
1919 SHA_Init(&ssh->exhashbase);
1920 /*
1921 * Hash our version string and their version string.
1922 */
1923 sha_string(&ssh->exhashbase, verstring, strlen(verstring));
1924 sha_string(&ssh->exhashbase, s->vstring, strcspn(s->vstring, "\r\n"));
1925 sprintf(vlog, "We claim version: %s", verstring);
1926 logevent(vlog);
1927 strcat(verstring, "\012");
1928 logevent("Using SSH protocol version 2");
1929 sk_write(ssh->s, verstring, strlen(verstring));
1930 ssh->protocol = ssh2_protocol;
1931 ssh->version = 2;
1932 ssh->s_rdpkt = ssh2_rdpkt;
1933 } else {
1934 /*
1935 * Use v1 protocol.
1936 */
1937 char verstring[80], vlog[100];
1938 sprintf(verstring, "SSH-%s-%s",
1939 (ssh_versioncmp(s->version, "1.5") <= 0 ? s->version : "1.5"),
1940 sshver);
1941 sprintf(vlog, "We claim version: %s", verstring);
1942 logevent(vlog);
1943 strcat(verstring, "\012");
1944
1945 logevent("Using SSH protocol version 1");
1946 sk_write(ssh->s, verstring, strlen(verstring));
1947 ssh->protocol = ssh1_protocol;
1948 ssh->version = 1;
1949 ssh->s_rdpkt = ssh1_rdpkt;
1950 }
1951 ssh->state = SSH_STATE_BEFORE_SIZE;
1952
1953 sfree(s->vstring);
1954
1955 crFinish(0);
1956 }
1957
1958 static void ssh_gotdata(Ssh ssh, unsigned char *data, int datalen)
1959 {
1960 crBegin(ssh->ssh_gotdata_crstate);
1961
1962 /*
1963 * To begin with, feed the characters one by one to the
1964 * protocol initialisation / selection function do_ssh_init().
1965 * When that returns 0, we're done with the initial greeting
1966 * exchange and can move on to packet discipline.
1967 */
1968 while (1) {
1969 int ret; /* need not be kept across crReturn */
1970 if (datalen == 0)
1971 crReturnV; /* more data please */
1972 ret = do_ssh_init(ssh, *data);
1973 data++;
1974 datalen--;
1975 if (ret == 0)
1976 break;
1977 }
1978
1979 /*
1980 * We emerge from that loop when the initial negotiation is
1981 * over and we have selected an s_rdpkt function. Now pass
1982 * everything to s_rdpkt, and then pass the resulting packets
1983 * to the proper protocol handler.
1984 */
1985 if (datalen == 0)
1986 crReturnV;
1987 while (1) {
1988 while (datalen > 0) {
1989 if (ssh->s_rdpkt(ssh, &data, &datalen) == 0) {
1990 if (ssh->state == SSH_STATE_CLOSED) {
1991 return;
1992 }
1993 ssh->protocol(ssh, NULL, 0, 1);
1994 if (ssh->state == SSH_STATE_CLOSED) {
1995 return;
1996 }
1997 }
1998 }
1999 crReturnV;
2000 }
2001 crFinishV;
2002 }
2003
2004 static int ssh_closing(Plug plug, char *error_msg, int error_code,
2005 int calling_back)
2006 {
2007 Ssh ssh = (Ssh) plug;
2008 ssh->state = SSH_STATE_CLOSED;
2009 if (ssh->s) {
2010 sk_close(ssh->s);
2011 ssh->s = NULL;
2012 }
2013 if (error_msg) {
2014 /* A socket error has occurred. */
2015 logevent(error_msg);
2016 connection_fatal(ssh->frontend, error_msg);
2017 } else {
2018 /* Otherwise, the remote side closed the connection normally. */
2019 }
2020 return 0;
2021 }
2022
2023 static int ssh_receive(Plug plug, int urgent, char *data, int len)
2024 {
2025 Ssh ssh = (Ssh) plug;
2026 ssh_gotdata(ssh, (unsigned char *)data, len);
2027 if (ssh->state == SSH_STATE_CLOSED) {
2028 if (ssh->s) {
2029 sk_close(ssh->s);
2030 ssh->s = NULL;
2031 }
2032 return 0;
2033 }
2034 return 1;
2035 }
2036
2037 static void ssh_sent(Plug plug, int bufsize)
2038 {
2039 Ssh ssh = (Ssh) plug;
2040 /*
2041 * If the send backlog on the SSH socket itself clears, we
2042 * should unthrottle the whole world if it was throttled.
2043 */
2044 if (bufsize < SSH_MAX_BACKLOG)
2045 ssh_throttle_all(ssh, 0, bufsize);
2046 }
2047
2048 /*
2049 * Connect to specified host and port.
2050 * Returns an error message, or NULL on success.
2051 * Also places the canonical host name into `realhost'. It must be
2052 * freed by the caller.
2053 */
2054 static char *connect_to_host(Ssh ssh, char *host, int port,
2055 char **realhost, int nodelay)
2056 {
2057 static const struct plug_function_table fn_table = {
2058 ssh_closing,
2059 ssh_receive,
2060 ssh_sent,
2061 NULL
2062 };
2063
2064 SockAddr addr;
2065 char *err;
2066
2067 ssh->savedhost = smalloc(1 + strlen(host));
2068 if (!ssh->savedhost)
2069 fatalbox("Out of memory");
2070 strcpy(ssh->savedhost, host);
2071
2072 if (port < 0)
2073 port = 22; /* default ssh port */
2074 ssh->savedport = port;
2075
2076 /*
2077 * Try to find host.
2078 */
2079 logeventf(ssh, "Looking up host \"%s\"", host);
2080 addr = name_lookup(host, port, realhost, &ssh->cfg);
2081 if ((err = sk_addr_error(addr)) != NULL)
2082 return err;
2083
2084 /*
2085 * Open socket.
2086 */
2087 {
2088 char addrbuf[100];
2089 sk_getaddr(addr, addrbuf, 100);
2090 logeventf(ssh, "Connecting to %s port %d", addrbuf, port);
2091 }
2092 ssh->fn = &fn_table;
2093 ssh->s = new_connection(addr, *realhost, port,
2094 0, 1, nodelay, (Plug) ssh, &ssh->cfg);
2095 if ((err = sk_socket_error(ssh->s)) != NULL) {
2096 ssh->s = NULL;
2097 return err;
2098 }
2099
2100 return NULL;
2101 }
2102
2103 /*
2104 * Throttle or unthrottle the SSH connection.
2105 */
2106 static void ssh1_throttle(Ssh ssh, int adjust)
2107 {
2108 int old_count = ssh->v1_throttle_count;
2109 ssh->v1_throttle_count += adjust;
2110 assert(ssh->v1_throttle_count >= 0);
2111 if (ssh->v1_throttle_count && !old_count) {
2112 sk_set_frozen(ssh->s, 1);
2113 } else if (!ssh->v1_throttle_count && old_count) {
2114 sk_set_frozen(ssh->s, 0);
2115 }
2116 }
2117
2118 /*
2119 * Throttle or unthrottle _all_ local data streams (for when sends
2120 * on the SSH connection itself back up).
2121 */
2122 static void ssh_throttle_all(Ssh ssh, int enable, int bufsize)
2123 {
2124 int i;
2125 struct ssh_channel *c;
2126
2127 if (enable == ssh->throttled_all)
2128 return;
2129 ssh->throttled_all = enable;
2130 ssh->overall_bufsize = bufsize;
2131 if (!ssh->channels)
2132 return;
2133 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
2134 switch (c->type) {
2135 case CHAN_MAINSESSION:
2136 /*
2137 * This is treated separately, outside the switch.
2138 */
2139 break;
2140 case CHAN_X11:
2141 x11_override_throttle(c->u.x11.s, enable);
2142 break;
2143 case CHAN_AGENT:
2144 /* Agent channels require no buffer management. */
2145 break;
2146 case CHAN_SOCKDATA:
2147 pfd_override_throttle(c->u.x11.s, enable);
2148 break;
2149 }
2150 }
2151 }
2152
2153 /*
2154 * Username and password input, abstracted off into routines
2155 * reusable in several places - even between SSH1 and SSH2.
2156 */
2157
2158 /* Set up a username or password input loop on a given buffer. */
2159 static void setup_userpass_input(Ssh ssh, char *buffer, int buflen, int echo)
2160 {
2161 ssh->userpass_input_buffer = buffer;
2162 ssh->userpass_input_buflen = buflen;
2163 ssh->userpass_input_bufpos = 0;
2164 ssh->userpass_input_echo = echo;
2165 }
2166
2167 /*
2168 * Process some terminal data in the course of username/password
2169 * input. Returns >0 for success (line of input returned in
2170 * buffer), <0 for failure (user hit ^C/^D, bomb out and exit), 0
2171 * for inconclusive (keep waiting for more input please).
2172 */
2173 static int process_userpass_input(Ssh ssh, unsigned char *in, int inlen)
2174 {
2175 char c;
2176
2177 while (inlen--) {
2178 switch (c = *in++) {
2179 case 10:
2180 case 13:
2181 ssh->userpass_input_buffer[ssh->userpass_input_bufpos] = 0;
2182 ssh->userpass_input_buffer[ssh->userpass_input_buflen-1] = 0;
2183 return +1;
2184 break;
2185 case 8:
2186 case 127:
2187 if (ssh->userpass_input_bufpos > 0) {
2188 if (ssh->userpass_input_echo)
2189 c_write_str(ssh, "\b \b");
2190 ssh->userpass_input_bufpos--;
2191 }
2192 break;
2193 case 21:
2194 case 27:
2195 while (ssh->userpass_input_bufpos > 0) {
2196 if (ssh->userpass_input_echo)
2197 c_write_str(ssh, "\b \b");
2198 ssh->userpass_input_bufpos--;
2199 }
2200 break;
2201 case 3:
2202 case 4:
2203 return -1;
2204 break;
2205 default:
2206 /*
2207 * This simplistic check for printability is disabled
2208 * when we're doing password input, because some people
2209 * have control characters in their passwords.o
2210 */
2211 if ((!ssh->userpass_input_echo ||
2212 (c >= ' ' && c <= '~') ||
2213 ((unsigned char) c >= 160))
2214 && ssh->userpass_input_bufpos < ssh->userpass_input_buflen-1) {
2215 ssh->userpass_input_buffer[ssh->userpass_input_bufpos++] = c;
2216 if (ssh->userpass_input_echo)
2217 c_write(ssh, &c, 1);
2218 }
2219 break;
2220 }
2221 }
2222 return 0;
2223 }
2224
2225 /*
2226 * Handle the key exchange and user authentication phases.
2227 */
2228 static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
2229 {
2230 int i, j;
2231 unsigned char cookie[8];
2232 struct RSAKey servkey, hostkey;
2233 struct MD5Context md5c;
2234 struct do_ssh1_login_state {
2235 int len;
2236 unsigned char *rsabuf, *keystr1, *keystr2;
2237 unsigned long supported_ciphers_mask, supported_auths_mask;
2238 int tried_publickey, tried_agent;
2239 int tis_auth_refused, ccard_auth_refused;
2240 unsigned char session_id[16];
2241 int cipher_type;
2242 char username[100];
2243 void *publickey_blob;
2244 int publickey_bloblen;
2245 char password[100];
2246 char prompt[200];
2247 int pos;
2248 char c;
2249 int pwpkt_type;
2250 unsigned char request[5], *response, *p;
2251 int responselen;
2252 int keyi, nkeys;
2253 int authed;
2254 struct RSAKey key;
2255 Bignum challenge;
2256 char *commentp;
2257 int commentlen;
2258 };
2259 crState(do_ssh1_login_state);
2260
2261 crBegin(ssh->do_ssh1_login_crstate);
2262
2263 if (!ispkt)
2264 crWaitUntil(ispkt);
2265
2266 if (ssh->pktin.type != SSH1_SMSG_PUBLIC_KEY) {
2267 bombout((ssh,"Public key packet not received"));
2268 crReturn(0);
2269 }
2270
2271 logevent("Received public keys");
2272
2273 memcpy(cookie, ssh->pktin.body, 8);
2274
2275 i = makekey(ssh->pktin.body + 8, &servkey, &s->keystr1, 0);
2276 j = makekey(ssh->pktin.body + 8 + i, &hostkey, &s->keystr2, 0);
2277
2278 /*
2279 * Log the host key fingerprint.
2280 */
2281 {
2282 char logmsg[80];
2283 logevent("Host key fingerprint is:");
2284 strcpy(logmsg, " ");
2285 hostkey.comment = NULL;
2286 rsa_fingerprint(logmsg + strlen(logmsg),
2287 sizeof(logmsg) - strlen(logmsg), &hostkey);
2288 logevent(logmsg);
2289 }
2290
2291 ssh->v1_remote_protoflags = GET_32BIT(ssh->pktin.body + 8 + i + j);
2292 s->supported_ciphers_mask = GET_32BIT(ssh->pktin.body + 12 + i + j);
2293 s->supported_auths_mask = GET_32BIT(ssh->pktin.body + 16 + i + j);
2294
2295 ssh->v1_local_protoflags =
2296 ssh->v1_remote_protoflags & SSH1_PROTOFLAGS_SUPPORTED;
2297 ssh->v1_local_protoflags |= SSH1_PROTOFLAG_SCREEN_NUMBER;
2298
2299 MD5Init(&md5c);
2300 MD5Update(&md5c, s->keystr2, hostkey.bytes);
2301 MD5Update(&md5c, s->keystr1, servkey.bytes);
2302 MD5Update(&md5c, ssh->pktin.body, 8);
2303 MD5Final(s->session_id, &md5c);
2304
2305 for (i = 0; i < 32; i++)
2306 ssh->session_key[i] = random_byte();
2307
2308 s->len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes);
2309
2310 s->rsabuf = smalloc(s->len);
2311 if (!s->rsabuf)
2312 fatalbox("Out of memory");
2313
2314 /*
2315 * Verify the host key.
2316 */
2317 {
2318 /*
2319 * First format the key into a string.
2320 */
2321 int len = rsastr_len(&hostkey);
2322 char fingerprint[100];
2323 char *keystr = smalloc(len);
2324 if (!keystr)
2325 fatalbox("Out of memory");
2326 rsastr_fmt(keystr, &hostkey);
2327 rsa_fingerprint(fingerprint, sizeof(fingerprint), &hostkey);
2328 verify_ssh_host_key(ssh->frontend,
2329 ssh->savedhost, ssh->savedport, "rsa", keystr,
2330 fingerprint);
2331 sfree(keystr);
2332 }
2333
2334 for (i = 0; i < 32; i++) {
2335 s->rsabuf[i] = ssh->session_key[i];
2336 if (i < 16)
2337 s->rsabuf[i] ^= s->session_id[i];
2338 }
2339
2340 if (hostkey.bytes > servkey.bytes) {
2341 rsaencrypt(s->rsabuf, 32, &servkey);
2342 rsaencrypt(s->rsabuf, servkey.bytes, &hostkey);
2343 } else {
2344 rsaencrypt(s->rsabuf, 32, &hostkey);
2345 rsaencrypt(s->rsabuf, hostkey.bytes, &servkey);
2346 }
2347
2348 logevent("Encrypted session key");
2349
2350 {
2351 int cipher_chosen = 0, warn = 0;
2352 char *cipher_string = NULL;
2353 int i;
2354 for (i = 0; !cipher_chosen && i < CIPHER_MAX; i++) {
2355 int next_cipher = ssh->cfg.ssh_cipherlist[i];
2356 if (next_cipher == CIPHER_WARN) {
2357 /* If/when we choose a cipher, warn about it */
2358 warn = 1;
2359 } else if (next_cipher == CIPHER_AES) {
2360 /* XXX Probably don't need to mention this. */
2361 logevent("AES not supported in SSH1, skipping");
2362 } else {
2363 switch (next_cipher) {
2364 case CIPHER_3DES: s->cipher_type = SSH_CIPHER_3DES;
2365 cipher_string = "3DES"; break;
2366 case CIPHER_BLOWFISH: s->cipher_type = SSH_CIPHER_BLOWFISH;
2367 cipher_string = "Blowfish"; break;
2368 case CIPHER_DES: s->cipher_type = SSH_CIPHER_DES;
2369 cipher_string = "single-DES"; break;
2370 }
2371 if (s->supported_ciphers_mask & (1 << s->cipher_type))
2372 cipher_chosen = 1;
2373 }
2374 }
2375 if (!cipher_chosen) {
2376 if ((s->supported_ciphers_mask & (1 << SSH_CIPHER_3DES)) == 0)
2377 bombout((ssh,"Server violates SSH 1 protocol by not "
2378 "supporting 3DES encryption"));
2379 else
2380 /* shouldn't happen */
2381 bombout((ssh,"No supported ciphers found"));
2382 crReturn(0);
2383 }
2384
2385 /* Warn about chosen cipher if necessary. */
2386 if (warn)
2387 askcipher(ssh->frontend, cipher_string, 0);
2388 }
2389
2390 switch (s->cipher_type) {
2391 case SSH_CIPHER_3DES:
2392 logevent("Using 3DES encryption");
2393 break;
2394 case SSH_CIPHER_DES:
2395 logevent("Using single-DES encryption");
2396 break;
2397 case SSH_CIPHER_BLOWFISH:
2398 logevent("Using Blowfish encryption");
2399 break;
2400 }
2401
2402 send_packet(ssh, SSH1_CMSG_SESSION_KEY,
2403 PKT_CHAR, s->cipher_type,
2404 PKT_DATA, cookie, 8,
2405 PKT_CHAR, (s->len * 8) >> 8, PKT_CHAR, (s->len * 8) & 0xFF,
2406 PKT_DATA, s->rsabuf, s->len,
2407 PKT_INT, ssh->v1_local_protoflags, PKT_END);
2408
2409 logevent("Trying to enable encryption...");
2410
2411 sfree(s->rsabuf);
2412
2413 ssh->cipher = (s->cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 :
2414 s->cipher_type == SSH_CIPHER_DES ? &ssh_des :
2415 &ssh_3des);
2416 ssh->v1_cipher_ctx = ssh->cipher->make_context();
2417 ssh->cipher->sesskey(ssh->v1_cipher_ctx, ssh->session_key);
2418 logeventf(ssh, "Initialised %s encryption", ssh->cipher->text_name);
2419
2420 ssh->crcda_ctx = crcda_make_context();
2421 logevent("Installing CRC compensation attack detector");
2422
2423 crWaitUntil(ispkt);
2424
2425 if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
2426 bombout((ssh,"Encryption not successfully enabled"));
2427 crReturn(0);
2428 }
2429
2430 logevent("Successfully started encryption");
2431
2432 fflush(stdout);
2433 {
2434 if ((flags & FLAG_INTERACTIVE) && !*ssh->cfg.username) {
2435 if (ssh_get_line && !ssh_getline_pw_only) {
2436 if (!ssh_get_line("login as: ",
2437 s->username, sizeof(s->username), FALSE)) {
2438 /*
2439 * get_line failed to get a username.
2440 * Terminate.
2441 */
2442 logevent("No username provided. Abandoning session.");
2443 ssh->state = SSH_STATE_CLOSED;
2444 crReturn(1);
2445 }
2446 } else {
2447 int ret; /* need not be kept over crReturn */
2448 c_write_str(ssh, "login as: ");
2449 ssh->send_ok = 1;
2450
2451 setup_userpass_input(ssh, s->username, sizeof(s->username), 1);
2452 do {
2453 crWaitUntil(!ispkt);
2454 ret = process_userpass_input(ssh, in, inlen);
2455 } while (ret == 0);
2456 if (ret < 0)
2457 cleanup_exit(0);
2458 c_write_str(ssh, "\r\n");
2459 }
2460 } else {
2461 strncpy(s->username, ssh->cfg.username, sizeof(s->username));
2462 s->username[sizeof(s->username)-1] = '\0';
2463 }
2464
2465 send_packet(ssh, SSH1_CMSG_USER, PKT_STR, s->username, PKT_END);
2466 {
2467 char userlog[22 + sizeof(s->username)];
2468 sprintf(userlog, "Sent username \"%s\"", s->username);
2469 logevent(userlog);
2470 if (flags & FLAG_INTERACTIVE &&
2471 (!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) {
2472 strcat(userlog, "\r\n");
2473 c_write_str(ssh, userlog);
2474 }
2475 }
2476 }
2477
2478 crWaitUntil(ispkt);
2479
2480 if ((ssh->remote_bugs & BUG_CHOKES_ON_RSA)) {
2481 /* We must not attempt PK auth. Pretend we've already tried it. */
2482 s->tried_publickey = s->tried_agent = 1;
2483 } else {
2484 s->tried_publickey = s->tried_agent = 0;
2485 }
2486 s->tis_auth_refused = s->ccard_auth_refused = 0;
2487 /* Load the public half of ssh->cfg.keyfile so we notice if it's in Pageant */
2488 if (!filename_is_null(ssh->cfg.keyfile)) {
2489 if (!rsakey_pubblob(&ssh->cfg.keyfile,
2490 &s->publickey_blob, &s->publickey_bloblen))
2491 s->publickey_blob = NULL;
2492 } else
2493 s->publickey_blob = NULL;
2494
2495 while (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2496 s->pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
2497
2498 if (agent_exists() && !s->tried_agent) {
2499 /*
2500 * Attempt RSA authentication using Pageant.
2501 */
2502 void *r;
2503
2504 s->authed = FALSE;
2505 s->tried_agent = 1;
2506 logevent("Pageant is running. Requesting keys.");
2507
2508 /* Request the keys held by the agent. */
2509 PUT_32BIT(s->request, 1);
2510 s->request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES;
2511 agent_query(s->request, 5, &r, &s->responselen);
2512 s->response = (unsigned char *) r;
2513 if (s->response && s->responselen >= 5 &&
2514 s->response[4] == SSH1_AGENT_RSA_IDENTITIES_ANSWER) {
2515 s->p = s->response + 5;
2516 s->nkeys = GET_32BIT(s->p);
2517 s->p += 4;
2518 {
2519 char buf[64];
2520 sprintf(buf, "Pageant has %d SSH1 keys", s->nkeys);
2521 logevent(buf);
2522 }
2523 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
2524 {
2525 char buf[64];
2526 sprintf(buf, "Trying Pageant key #%d", s->keyi);
2527 logevent(buf);
2528 }
2529 if (s->publickey_blob &&
2530 !memcmp(s->p, s->publickey_blob,
2531 s->publickey_bloblen)) {
2532 logevent("This key matches configured key file");
2533 s->tried_publickey = 1;
2534 }
2535 s->p += 4;
2536 s->p += ssh1_read_bignum(s->p, &s->key.exponent);
2537 s->p += ssh1_read_bignum(s->p, &s->key.modulus);
2538 s->commentlen = GET_32BIT(s->p);
2539 s->p += 4;
2540 s->commentp = (char *)s->p;
2541 s->p += s->commentlen;
2542 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
2543 PKT_BIGNUM, s->key.modulus, PKT_END);
2544 crWaitUntil(ispkt);
2545 if (ssh->pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
2546 logevent("Key refused");
2547 continue;
2548 }
2549 logevent("Received RSA challenge");
2550 ssh1_read_bignum(ssh->pktin.body, &s->challenge);
2551 {
2552 char *agentreq, *q, *ret;
2553 void *vret;
2554 int len, retlen;
2555 len = 1 + 4; /* message type, bit count */
2556 len += ssh1_bignum_length(s->key.exponent);
2557 len += ssh1_bignum_length(s->key.modulus);
2558 len += ssh1_bignum_length(s->challenge);
2559 len += 16; /* session id */
2560 len += 4; /* response format */
2561 agentreq = smalloc(4 + len);
2562 PUT_32BIT(agentreq, len);
2563 q = agentreq + 4;
2564 *q++ = SSH1_AGENTC_RSA_CHALLENGE;
2565 PUT_32BIT(q, bignum_bitcount(s->key.modulus));
2566 q += 4;
2567 q += ssh1_write_bignum(q, s->key.exponent);
2568 q += ssh1_write_bignum(q, s->key.modulus);
2569 q += ssh1_write_bignum(q, s->challenge);
2570 memcpy(q, s->session_id, 16);
2571 q += 16;
2572 PUT_32BIT(q, 1); /* response format */
2573 agent_query(agentreq, len + 4, &vret, &retlen);
2574 ret = vret;
2575 sfree(agentreq);
2576 if (ret) {
2577 if (ret[4] == SSH1_AGENT_RSA_RESPONSE) {
2578 logevent("Sending Pageant's response");
2579 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
2580 PKT_DATA, ret + 5, 16,
2581 PKT_END);
2582 sfree(ret);
2583 crWaitUntil(ispkt);
2584 if (ssh->pktin.type == SSH1_SMSG_SUCCESS) {
2585 logevent
2586 ("Pageant's response accepted");
2587 if (flags & FLAG_VERBOSE) {
2588 c_write_str(ssh, "Authenticated using"
2589 " RSA key \"");
2590 c_write(ssh, s->commentp,
2591 s->commentlen);
2592 c_write_str(ssh, "\" from agent\r\n");
2593 }
2594 s->authed = TRUE;
2595 } else
2596 logevent
2597 ("Pageant's response not accepted");
2598 } else {
2599 logevent
2600 ("Pageant failed to answer challenge");
2601 sfree(ret);
2602 }
2603 } else {
2604 logevent("No reply received from Pageant");
2605 }
2606 }
2607 freebn(s->key.exponent);
2608 freebn(s->key.modulus);
2609 freebn(s->challenge);
2610 if (s->authed)
2611 break;
2612 }
2613 }
2614 if (s->authed)
2615 break;
2616 }
2617 if (!filename_is_null(ssh->cfg.keyfile) && !s->tried_publickey)
2618 s->pwpkt_type = SSH1_CMSG_AUTH_RSA;
2619
2620 if (ssh->cfg.try_tis_auth &&
2621 (s->supported_auths_mask & (1 << SSH1_AUTH_TIS)) &&
2622 !s->tis_auth_refused) {
2623 s->pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
2624 logevent("Requested TIS authentication");
2625 send_packet(ssh, SSH1_CMSG_AUTH_TIS, PKT_END);
2626 crWaitUntil(ispkt);
2627 if (ssh->pktin.type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
2628 logevent("TIS authentication declined");
2629 if (flags & FLAG_INTERACTIVE)
2630 c_write_str(ssh, "TIS authentication refused.\r\n");
2631 s->tis_auth_refused = 1;
2632 continue;
2633 } else {
2634 int challengelen = GET_32BIT(ssh->pktin.body);
2635 logevent("Received TIS challenge");
2636 if (challengelen > sizeof(s->prompt) - 1)
2637 challengelen = sizeof(s->prompt) - 1;/* prevent overrun */
2638 memcpy(s->prompt, ssh->pktin.body + 4, challengelen);
2639 /* Prompt heuristic comes from OpenSSH */
2640 strncpy(s->prompt + challengelen,
2641 memchr(s->prompt, '\n', challengelen) ?
2642 "": "\r\nResponse: ",
2643 (sizeof s->prompt) - challengelen);
2644 s->prompt[(sizeof s->prompt) - 1] = '\0';
2645 }
2646 }
2647 if (ssh->cfg.try_tis_auth &&
2648 (s->supported_auths_mask & (1 << SSH1_AUTH_CCARD)) &&
2649 !s->ccard_auth_refused) {
2650 s->pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE;
2651 logevent("Requested CryptoCard authentication");
2652 send_packet(ssh, SSH1_CMSG_AUTH_CCARD, PKT_END);
2653 crWaitUntil(ispkt);
2654 if (ssh->pktin.type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
2655 logevent("CryptoCard authentication declined");
2656 c_write_str(ssh, "CryptoCard authentication refused.\r\n");
2657 s->ccard_auth_refused = 1;
2658 continue;
2659 } else {
2660 int challengelen = GET_32BIT(ssh->pktin.body);
2661 logevent("Received CryptoCard challenge");
2662 if (challengelen > sizeof(s->prompt) - 1)
2663 challengelen = sizeof(s->prompt) - 1;/* prevent overrun */
2664 memcpy(s->prompt, ssh->pktin.body + 4, challengelen);
2665 strncpy(s->prompt + challengelen,
2666 memchr(s->prompt, '\n', challengelen) ?
2667 "" : "\r\nResponse: ",
2668 sizeof(s->prompt) - challengelen);
2669 s->prompt[sizeof(s->prompt) - 1] = '\0';
2670 }
2671 }
2672 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
2673 sprintf(s->prompt, "%.90s@%.90s's password: ",
2674 s->username, ssh->savedhost);
2675 }
2676 if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) {
2677 char *comment = NULL;
2678 int type;
2679 char msgbuf[256];
2680 if (flags & FLAG_VERBOSE)
2681 c_write_str(ssh, "Trying public key authentication.\r\n");
2682 logeventf(ssh, "Trying public key \"%s\"",
2683 filename_to_str(&ssh->cfg.keyfile));
2684 type = key_type(&ssh->cfg.keyfile);
2685 if (type != SSH_KEYTYPE_SSH1) {
2686 sprintf(msgbuf, "Key is of wrong type (%s)",
2687 key_type_to_str(type));
2688 logevent(msgbuf);
2689 c_write_str(ssh, msgbuf);
2690 c_write_str(ssh, "\r\n");
2691 s->tried_publickey = 1;
2692 continue;
2693 }
2694 if (!rsakey_encrypted(&ssh->cfg.keyfile, &comment)) {
2695 if (flags & FLAG_VERBOSE)
2696 c_write_str(ssh, "No passphrase required.\r\n");
2697 goto tryauth;
2698 }
2699 sprintf(s->prompt, "Passphrase for key \"%.100s\": ", comment);
2700 sfree(comment);
2701 }
2702
2703 /*
2704 * Show password prompt, having first obtained it via a TIS
2705 * or CryptoCard exchange if we're doing TIS or CryptoCard
2706 * authentication.
2707 */
2708 if (ssh_get_line) {
2709 if (!ssh_get_line(s->prompt, s->password,
2710 sizeof(s->password), TRUE)) {
2711 /*
2712 * get_line failed to get a password (for example
2713 * because one was supplied on the command line
2714 * which has already failed to work). Terminate.
2715 */
2716 send_packet(ssh, SSH1_MSG_DISCONNECT,
2717 PKT_STR, "No more passwords available to try",
2718 PKT_END);
2719 logevent("Unable to authenticate");
2720 connection_fatal(ssh->frontend, "Unable to authenticate");
2721 ssh->state = SSH_STATE_CLOSED;
2722 crReturn(1);
2723 }
2724 } else {
2725 /* Prompt may have come from server. We've munged it a bit, so
2726 * we know it to be zero-terminated at least once. */
2727 int ret; /* need not be saved over crReturn */
2728 c_write_untrusted(ssh, s->prompt, strlen(s->prompt));
2729 s->pos = 0;
2730
2731 setup_userpass_input(ssh, s->password, sizeof(s->password), 0);
2732 do {
2733 crWaitUntil(!ispkt);
2734 ret = process_userpass_input(ssh, in, inlen);
2735 } while (ret == 0);
2736 if (ret < 0)
2737 cleanup_exit(0);
2738 c_write_str(ssh, "\r\n");
2739 }
2740
2741 tryauth:
2742 if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) {
2743 /*
2744 * Try public key authentication with the specified
2745 * key file.
2746 */
2747 s->tried_publickey = 1;
2748
2749 {
2750 int ret = loadrsakey(&ssh->cfg.keyfile, &s->key, s->password);
2751 if (ret == 0) {
2752 c_write_str(ssh, "Couldn't load private key from ");
2753 c_write_str(ssh, filename_to_str(&ssh->cfg.keyfile));
2754 c_write_str(ssh, ".\r\n");
2755 continue; /* go and try password */
2756 }
2757 if (ret == -1) {
2758 c_write_str(ssh, "Wrong passphrase.\r\n");
2759 s->tried_publickey = 0;
2760 continue; /* try again */
2761 }
2762 }
2763
2764 /*
2765 * Send a public key attempt.
2766 */
2767 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
2768 PKT_BIGNUM, s->key.modulus, PKT_END);
2769
2770 crWaitUntil(ispkt);
2771 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2772 c_write_str(ssh, "Server refused our public key.\r\n");
2773 continue; /* go and try password */
2774 }
2775 if (ssh->pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
2776 bombout((ssh,"Bizarre response to offer of public key"));
2777 crReturn(0);
2778 }
2779
2780 {
2781 int i;
2782 unsigned char buffer[32];
2783 Bignum challenge, response;
2784
2785 ssh1_read_bignum(ssh->pktin.body, &challenge);
2786 response = rsadecrypt(challenge, &s->key);
2787 freebn(s->key.private_exponent);/* burn the evidence */
2788
2789 for (i = 0; i < 32; i++) {
2790 buffer[i] = bignum_byte(response, 31 - i);
2791 }
2792
2793 MD5Init(&md5c);
2794 MD5Update(&md5c, buffer, 32);
2795 MD5Update(&md5c, s->session_id, 16);
2796 MD5Final(buffer, &md5c);
2797
2798 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
2799 PKT_DATA, buffer, 16, PKT_END);
2800
2801 freebn(challenge);
2802 freebn(response);
2803 }
2804
2805 crWaitUntil(ispkt);
2806 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2807 if (flags & FLAG_VERBOSE)
2808 c_write_str(ssh, "Failed to authenticate with"
2809 " our public key.\r\n");
2810 continue; /* go and try password */
2811 } else if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
2812 bombout((ssh,"Bizarre response to RSA authentication response"));
2813 crReturn(0);
2814 }
2815
2816 break; /* we're through! */
2817 } else {
2818 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
2819 /*
2820 * Defence against traffic analysis: we send a
2821 * whole bunch of packets containing strings of
2822 * different lengths. One of these strings is the
2823 * password, in a SSH1_CMSG_AUTH_PASSWORD packet.
2824 * The others are all random data in
2825 * SSH1_MSG_IGNORE packets. This way a passive
2826 * listener can't tell which is the password, and
2827 * hence can't deduce the password length.
2828 *
2829 * Anybody with a password length greater than 16
2830 * bytes is going to have enough entropy in their
2831 * password that a listener won't find it _that_
2832 * much help to know how long it is. So what we'll
2833 * do is:
2834 *
2835 * - if password length < 16, we send 15 packets
2836 * containing string lengths 1 through 15
2837 *
2838 * - otherwise, we let N be the nearest multiple
2839 * of 8 below the password length, and send 8
2840 * packets containing string lengths N through
2841 * N+7. This won't obscure the order of
2842 * magnitude of the password length, but it will
2843 * introduce a bit of extra uncertainty.
2844 *
2845 * A few servers (the old 1.2.18 through 1.2.22)
2846 * can't deal with SSH1_MSG_IGNORE. For these
2847 * servers, we need an alternative defence. We make
2848 * use of the fact that the password is interpreted
2849 * as a C string: so we can append a NUL, then some
2850 * random data.
2851 *
2852 * One server (a Cisco one) can deal with neither
2853 * SSH1_MSG_IGNORE _nor_ a padded password string.
2854 * For this server we are left with no defences
2855 * against password length sniffing.
2856 */
2857 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE)) {
2858 /*
2859 * The server can deal with SSH1_MSG_IGNORE, so
2860 * we can use the primary defence.
2861 */
2862 int bottom, top, pwlen, i;
2863 char *randomstr;
2864
2865 pwlen = strlen(s->password);
2866 if (pwlen < 16) {
2867 bottom = 0; /* zero length passwords are OK! :-) */
2868 top = 15;
2869 } else {
2870 bottom = pwlen & ~7;
2871 top = bottom + 7;
2872 }
2873
2874 assert(pwlen >= bottom && pwlen <= top);
2875
2876 randomstr = smalloc(top + 1);
2877
2878 for (i = bottom; i <= top; i++) {
2879 if (i == pwlen)
2880 defer_packet(ssh, s->pwpkt_type,
2881 PKT_STR, s->password, PKT_END);
2882 else {
2883 for (j = 0; j < i; j++) {
2884 do {
2885 randomstr[j] = random_byte();
2886 } while (randomstr[j] == '\0');
2887 }
2888 randomstr[i] = '\0';
2889 defer_packet(ssh, SSH1_MSG_IGNORE,
2890 PKT_STR, randomstr, PKT_END);
2891 }
2892 }
2893 logevent("Sending password with camouflage packets");
2894 ssh_pkt_defersend(ssh);
2895 }
2896 else if (!(ssh->remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) {
2897 /*
2898 * The server can't deal with SSH1_MSG_IGNORE
2899 * but can deal with padded passwords, so we
2900 * can use the secondary defence.
2901 */
2902 char string[64];
2903 char *ss;
2904 int len;
2905
2906 len = strlen(s->password);
2907 if (len < sizeof(string)) {
2908 ss = string;
2909 strcpy(string, s->password);
2910 len++; /* cover the zero byte */
2911 while (len < sizeof(string)) {
2912 string[len++] = (char) random_byte();
2913 }
2914 } else {
2915 ss = s->password;
2916 }
2917 logevent("Sending length-padded password");
2918 send_packet(ssh, s->pwpkt_type, PKT_INT, len,
2919 PKT_DATA, ss, len, PKT_END);
2920 } else {
2921 /*
2922 * The server has _both_
2923 * BUG_CHOKES_ON_SSH1_IGNORE and
2924 * BUG_NEEDS_SSH1_PLAIN_PASSWORD. There is
2925 * therefore nothing we can do.
2926 */
2927 int len;
2928 len = strlen(s->password);
2929 logevent("Sending unpadded password");
2930 send_packet(ssh, s->pwpkt_type, PKT_INT, len,
2931 PKT_DATA, s->password, len, PKT_END);
2932 }
2933 } else {
2934 send_packet(ssh, s->pwpkt_type, PKT_STR, s->password, PKT_END);
2935 }
2936 }
2937 logevent("Sent password");
2938 memset(s->password, 0, strlen(s->password));
2939 crWaitUntil(ispkt);
2940 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2941 if (flags & FLAG_VERBOSE)
2942 c_write_str(ssh, "Access denied\r\n");
2943 logevent("Authentication refused");
2944 } else if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
2945 bombout((ssh,"Strange packet received, type %d", ssh->pktin.type));
2946 crReturn(0);
2947 }
2948 }
2949
2950 logevent("Authentication successful");
2951
2952 crFinish(1);
2953 }
2954
2955 void sshfwd_close(struct ssh_channel *c)
2956 {
2957 Ssh ssh = c->ssh;
2958
2959 if (c && !c->closes) {
2960 /*
2961 * If the channel's remoteid is -1, we have sent
2962 * CHANNEL_OPEN for this channel, but it hasn't even been
2963 * acknowledged by the server. So we must set a close flag
2964 * on it now, and then when the server acks the channel
2965 * open, we can close it then.
2966 */
2967 if (((int)c->remoteid) != -1) {
2968 if (ssh->version == 1) {
2969 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid,
2970 PKT_END);
2971 } else {
2972 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
2973 ssh2_pkt_adduint32(ssh, c->remoteid);
2974 ssh2_pkt_send(ssh);
2975 }
2976 }
2977 c->closes = 1; /* sent MSG_CLOSE */
2978 if (c->type == CHAN_X11) {
2979 c->u.x11.s = NULL;
2980 logevent("Forwarded X11 connection terminated");
2981 } else if (c->type == CHAN_SOCKDATA ||
2982 c->type == CHAN_SOCKDATA_DORMANT) {
2983 c->u.pfd.s = NULL;
2984 logevent("Forwarded port closed");
2985 }
2986 }
2987 }
2988
2989 int sshfwd_write(struct ssh_channel *c, char *buf, int len)
2990 {
2991 Ssh ssh = c->ssh;
2992
2993 if (ssh->version == 1) {
2994 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
2995 PKT_INT, c->remoteid,
2996 PKT_INT, len, PKT_DATA, buf, len, PKT_END);
2997 /*
2998 * In SSH1 we can return 0 here - implying that forwarded
2999 * connections are never individually throttled - because
3000 * the only circumstance that can cause throttling will be
3001 * the whole SSH connection backing up, in which case
3002 * _everything_ will be throttled as a whole.
3003 */
3004 return 0;
3005 } else {
3006 ssh2_add_channel_data(c, buf, len);
3007 return ssh2_try_send(c);
3008 }
3009 }
3010
3011 void sshfwd_unthrottle(struct ssh_channel *c, int bufsize)
3012 {
3013 Ssh ssh = c->ssh;
3014
3015 if (ssh->version == 1) {
3016 if (c->v.v1.throttling && bufsize < SSH1_BUFFER_LIMIT) {
3017 c->v.v1.throttling = 0;
3018 ssh1_throttle(ssh, -1);
3019 }
3020 } else {
3021 ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
3022 }
3023 }
3024
3025 static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
3026 {
3027 crBegin(ssh->ssh1_protocol_crstate);
3028
3029 random_init();
3030
3031 while (!do_ssh1_login(ssh, in, inlen, ispkt)) {
3032 crReturnV;
3033 }
3034 if (ssh->state == SSH_STATE_CLOSED)
3035 crReturnV;
3036
3037 if (ssh->cfg.agentfwd && agent_exists()) {
3038 logevent("Requesting agent forwarding");
3039 send_packet(ssh, SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END);
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("Agent forwarding refused");
3049 } else {
3050 logevent("Agent forwarding enabled");
3051 ssh->agentfwd_enabled = TRUE;
3052 }
3053 }
3054
3055 if (ssh->cfg.x11_forward) {
3056 char proto[20], data[64];
3057 logevent("Requesting X11 forwarding");
3058 ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
3059 data, sizeof(data), ssh->cfg.x11_auth);
3060 x11_get_real_auth(ssh->x11auth, ssh->cfg.x11_display);
3061 if (ssh->v1_local_protoflags & SSH1_PROTOFLAG_SCREEN_NUMBER) {
3062 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
3063 PKT_STR, proto, PKT_STR, data,
3064 PKT_INT, x11_get_screen_number(ssh->cfg.x11_display),
3065 PKT_END);
3066 } else {
3067 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
3068 PKT_STR, proto, PKT_STR, data, PKT_END);
3069 }
3070 do {
3071 crReturnV;
3072 } while (!ispkt);
3073 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3074 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3075 bombout((ssh,"Protocol confusion"));
3076 crReturnV;
3077 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3078 logevent("X11 forwarding refused");
3079 } else {
3080 logevent("X11 forwarding enabled");
3081 ssh->X11_fwd_enabled = TRUE;
3082 }
3083 }
3084
3085 {
3086 char type;
3087 int n;
3088 int sport,dport,sserv,dserv;
3089 char sports[256], dports[256], saddr[256], host[256];
3090
3091 ssh->rportfwds = newtree234(ssh_rportcmp_ssh1);
3092 /* Add port forwardings. */
3093 ssh->portfwd_strptr = ssh->cfg.portfwd;
3094 while (*ssh->portfwd_strptr) {
3095 type = *ssh->portfwd_strptr++;
3096 saddr[0] = '\0';
3097 n = 0;
3098 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != '\t') {
3099 if (*ssh->portfwd_strptr == ':') {
3100 /*
3101 * We've seen a colon in the middle of the
3102 * source port number. This means that
3103 * everything we've seen until now is the
3104 * source _address_, so we'll move it into
3105 * saddr and start sports from the beginning
3106 * again.
3107 */
3108 ssh->portfwd_strptr++;
3109 sports[n] = '\0';
3110 strcpy(saddr, sports);
3111 n = 0;
3112 }
3113 if (n < 255) sports[n++] = *ssh->portfwd_strptr++;
3114 }
3115 sports[n] = 0;
3116 if (*ssh->portfwd_strptr == '\t')
3117 ssh->portfwd_strptr++;
3118 n = 0;
3119 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':') {
3120 if (n < 255) host[n++] = *ssh->portfwd_strptr++;
3121 }
3122 host[n] = 0;
3123 if (*ssh->portfwd_strptr == ':')
3124 ssh->portfwd_strptr++;
3125 n = 0;
3126 while (*ssh->portfwd_strptr) {
3127 if (n < 255) dports[n++] = *ssh->portfwd_strptr++;
3128 }
3129 dports[n] = 0;
3130 ssh->portfwd_strptr++;
3131 dport = atoi(dports);
3132 dserv = 0;
3133 if (dport == 0) {
3134 dserv = 1;
3135 dport = net_service_lookup(dports);
3136 if (!dport) {
3137 logeventf(ssh, "Service lookup failed for"
3138 " destination port \"%s\"", dports);
3139 }
3140 }
3141 sport = atoi(sports);
3142 sserv = 0;
3143 if (sport == 0) {
3144 sserv = 1;
3145 sport = net_service_lookup(sports);
3146 if (!sport) {
3147 logeventf(ssh, "Service lookup failed for source"
3148 " port \"%s\"", sports);
3149 }
3150 }
3151 if (sport && dport) {
3152 if (type == 'L') {
3153 pfd_addforward(host, dport, *saddr ? saddr : NULL,
3154 sport, ssh, &ssh->cfg);
3155 logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
3156 " forwarding to %s:%.*s%.*s%d%.*s",
3157 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
3158 (int)(*saddr?1:0), ":",
3159 (int)(sserv ? strlen(sports) : 0), sports,
3160 sserv, "(", sport, sserv, ")",
3161 host,
3162 (int)(dserv ? strlen(dports) : 0), dports,
3163 dserv, "(", dport, dserv, ")");
3164 } else {
3165 struct ssh_rportfwd *pf;
3166 pf = smalloc(sizeof(*pf));
3167 strcpy(pf->dhost, host);
3168 pf->dport = dport;
3169 if (saddr) {
3170 logeventf(ssh,
3171 "SSH1 cannot handle source address spec \"%s:%d\"; ignoring",
3172 saddr, sport);
3173 }
3174 if (add234(ssh->rportfwds, pf) != pf) {
3175 logeventf(ssh,
3176 "Duplicate remote port forwarding to %s:%d",
3177 host, dport);
3178 sfree(pf);
3179 } else {
3180 logeventf(ssh, "Requesting remote port %.*s%.*s%d%.*s"
3181 " forward to %s:%.*s%.*s%d%.*s",
3182 (int)(sserv ? strlen(sports) : 0), sports,
3183 sserv, "(", sport, sserv, ")",
3184 host,
3185 (int)(dserv ? strlen(dports) : 0), dports,
3186 dserv, "(", dport, dserv, ")");
3187 send_packet(ssh, SSH1_CMSG_PORT_FORWARD_REQUEST,
3188 PKT_INT, sport,
3189 PKT_STR, host,
3190 PKT_INT, dport,
3191 PKT_END);
3192 do {
3193 crReturnV;
3194 } while (!ispkt);
3195 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3196 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3197 bombout((ssh,"Protocol confusion"));
3198 crReturnV;
3199 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3200 c_write_str(ssh, "Server refused port"
3201 " forwarding\r\n");
3202 }
3203 logevent("Remote port forwarding enabled");
3204 }
3205 }
3206 }
3207 }
3208 }
3209
3210 if (!ssh->cfg.nopty) {
3211 send_packet(ssh, SSH1_CMSG_REQUEST_PTY,
3212 PKT_STR, ssh->cfg.termtype,
3213 PKT_INT, ssh->term_height,
3214 PKT_INT, ssh->term_width,
3215 PKT_INT, 0, PKT_INT, 0, PKT_CHAR, 0, PKT_END);
3216 ssh->state = SSH_STATE_INTERMED;
3217 do {
3218 crReturnV;
3219 } while (!ispkt);
3220 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3221 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3222 bombout((ssh,"Protocol confusion"));
3223 crReturnV;
3224 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3225 c_write_str(ssh, "Server refused to allocate pty\r\n");
3226 ssh->editing = ssh->echoing = 1;
3227 }
3228 logevent("Allocated pty");
3229 } else {
3230 ssh->editing = ssh->echoing = 1;
3231 }
3232
3233 if (ssh->cfg.compression) {
3234 send_packet(ssh, SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END);
3235 do {
3236 crReturnV;
3237 } while (!ispkt);
3238 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3239 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3240 bombout((ssh,"Protocol confusion"));
3241 crReturnV;
3242 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3243 c_write_str(ssh, "Server refused to compress\r\n");
3244 }
3245 logevent("Started compression");
3246 ssh->v1_compressing = TRUE;
3247 ssh->cs_comp_ctx = zlib_compress_init();
3248 logevent("Initialised zlib (RFC1950) compression");
3249 ssh->sc_comp_ctx = zlib_decompress_init();
3250 logevent("Initialised zlib (RFC1950) decompression");
3251 }
3252
3253 /*
3254 * Start the shell or command.
3255 *
3256 * Special case: if the first-choice command is an SSH2
3257 * subsystem (hence not usable here) and the second choice
3258 * exists, we fall straight back to that.
3259 */
3260 {
3261 char *cmd = ssh->cfg.remote_cmd_ptr;
3262
3263 if (ssh->cfg.ssh_subsys && ssh->cfg.remote_cmd_ptr2) {
3264 cmd = ssh->cfg.remote_cmd_ptr2;
3265 ssh->fallback_cmd = TRUE;
3266 }
3267 if (*cmd)
3268 send_packet(ssh, SSH1_CMSG_EXEC_CMD, PKT_STR, cmd, PKT_END);
3269 else
3270 send_packet(ssh, SSH1_CMSG_EXEC_SHELL, PKT_END);
3271 logevent("Started session");
3272 }
3273
3274 ssh->state = SSH_STATE_SESSION;
3275 if (ssh->size_needed)
3276 ssh_size(ssh, ssh->term_width, ssh->term_height);
3277 if (ssh->eof_needed)
3278 ssh_special(ssh, TS_EOF);
3279
3280 if (ssh->ldisc)
3281 ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */
3282 ssh->send_ok = 1;
3283 ssh->channels = newtree234(ssh_channelcmp);
3284 while (1) {
3285 crReturnV;
3286 if (ispkt) {
3287 if (ssh->pktin.type == SSH1_SMSG_STDOUT_DATA ||
3288 ssh->pktin.type == SSH1_SMSG_STDERR_DATA) {
3289 long len = GET_32BIT(ssh->pktin.body);
3290 int bufsize =
3291 from_backend(ssh->frontend,
3292 ssh->pktin.type == SSH1_SMSG_STDERR_DATA,
3293 (char *)(ssh->pktin.body) + 4, len);
3294 if (!ssh->v1_stdout_throttling && bufsize > SSH1_BUFFER_LIMIT) {
3295 ssh->v1_stdout_throttling = 1;
3296 ssh1_throttle(ssh, +1);
3297 }
3298 } else if (ssh->pktin.type == SSH1_MSG_DISCONNECT) {
3299 ssh->state = SSH_STATE_CLOSED;
3300 logevent("Received disconnect request");
3301 crReturnV;
3302 } else if (ssh->pktin.type == SSH1_SMSG_X11_OPEN) {
3303 /* Remote side is trying to open a channel to talk to our
3304 * X-Server. Give them back a local channel number. */
3305 struct ssh_channel *c;
3306
3307 logevent("Received X11 connect request");
3308 /* Refuse if X11 forwarding is disabled. */
3309 if (!ssh->X11_fwd_enabled) {
3310 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3311 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
3312 logevent("Rejected X11 connect request");
3313 } else {
3314 c = smalloc(sizeof(struct ssh_channel));
3315 c->ssh = ssh;
3316
3317 if (x11_init(&c->u.x11.s, ssh->cfg.x11_display, c,
3318 ssh->x11auth, NULL, -1, &ssh->cfg) != NULL) {
3319 logevent("opening X11 forward connection failed");
3320 sfree(c);
3321 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3322 PKT_INT, GET_32BIT(ssh->pktin.body),
3323 PKT_END);
3324 } else {
3325 logevent
3326 ("opening X11 forward connection succeeded");
3327 c->remoteid = GET_32BIT(ssh->pktin.body);
3328 c->localid = alloc_channel_id(ssh);
3329 c->closes = 0;
3330 c->v.v1.throttling = 0;
3331 c->type = CHAN_X11; /* identify channel type */
3332 add234(ssh->channels, c);
3333 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3334 PKT_INT, c->remoteid, PKT_INT,
3335 c->localid, PKT_END);
3336 logevent("Opened X11 forward channel");
3337 }
3338 }
3339 } else if (ssh->pktin.type == SSH1_SMSG_AGENT_OPEN) {
3340 /* Remote side is trying to open a channel to talk to our
3341 * agent. Give them back a local channel number. */
3342 struct ssh_channel *c;
3343
3344 /* Refuse if agent forwarding is disabled. */
3345 if (!ssh->agentfwd_enabled) {
3346 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3347 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
3348 } else {
3349 c = smalloc(sizeof(struct ssh_channel));
3350 c->ssh = ssh;
3351 c->remoteid = GET_32BIT(ssh->pktin.body);
3352 c->localid = alloc_channel_id(ssh);
3353 c->closes = 0;
3354 c->v.v1.throttling = 0;
3355 c->type = CHAN_AGENT; /* identify channel type */
3356 c->u.a.lensofar = 0;
3357 add234(ssh->channels, c);
3358 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3359 PKT_INT, c->remoteid, PKT_INT, c->localid,
3360 PKT_END);
3361 }
3362 } else if (ssh->pktin.type == SSH1_MSG_PORT_OPEN) {
3363 /* Remote side is trying to open a channel to talk to a
3364 * forwarded port. Give them back a local channel number. */
3365 struct ssh_channel *c;
3366 struct ssh_rportfwd pf;
3367 int hostsize, port;
3368 char host[256], buf[1024];
3369 char *p, *h, *e;
3370 c = smalloc(sizeof(struct ssh_channel));
3371 c->ssh = ssh;
3372
3373 hostsize = GET_32BIT(ssh->pktin.body+4);
3374 for (h = host, p = (char *)(ssh->pktin.body+8);
3375 hostsize != 0; hostsize--) {
3376 if (h+1 < host+sizeof(host))
3377 *h++ = *p;
3378 p++;
3379 }
3380 *h = 0;
3381 port = GET_32BIT(p);
3382
3383 strcpy(pf.dhost, host);
3384 pf.dport = port;
3385
3386 if (find234(ssh->rportfwds, &pf, NULL) == NULL) {
3387 sprintf(buf, "Rejected remote port open request for %s:%d",
3388 host, port);
3389 logevent(buf);
3390 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3391 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
3392 } else {
3393 sprintf(buf, "Received remote port open request for %s:%d",
3394 host, port);
3395 logevent(buf);
3396 e = pfd_newconnect(&c->u.pfd.s, host, port, c, &ssh->cfg);
3397 if (e != NULL) {
3398 char buf[256];
3399 sprintf(buf, "Port open failed: %s", e);
3400 logevent(buf);
3401 sfree(c);
3402 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3403 PKT_INT, GET_32BIT(ssh->pktin.body),
3404 PKT_END);
3405 } else {
3406 c->remoteid = GET_32BIT(ssh->pktin.body);
3407 c->localid = alloc_channel_id(ssh);
3408 c->closes = 0;
3409 c->v.v1.throttling = 0;
3410 c->type = CHAN_SOCKDATA; /* identify channel type */
3411 add234(ssh->channels, c);
3412 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3413 PKT_INT, c->remoteid, PKT_INT,
3414 c->localid, PKT_END);
3415 logevent("Forwarded port opened successfully");
3416 }
3417 }
3418
3419 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_OPEN_CONFIRMATION) {
3420 unsigned int remoteid = GET_32BIT(ssh->pktin.body);
3421 unsigned int localid = GET_32BIT(ssh->pktin.body+4);
3422 struct ssh_channel *c;
3423
3424 c = find234(ssh->channels, &remoteid, ssh_channelfind);
3425 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
3426 c->remoteid = localid;
3427 c->type = CHAN_SOCKDATA;
3428 c->v.v1.throttling = 0;
3429 pfd_confirm(c->u.pfd.s);
3430 }
3431
3432 if (c && c->closes) {
3433 /*
3434 * We have a pending close on this channel,
3435 * which we decided on before the server acked
3436 * the channel open. So now we know the
3437 * remoteid, we can close it again.
3438 */
3439 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE,
3440 PKT_INT, c->remoteid, PKT_END);
3441 }
3442
3443 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_OPEN_FAILURE) {
3444 unsigned int remoteid = GET_32BIT(ssh->pktin.body);
3445 struct ssh_channel *c;
3446
3447 c = find234(ssh->channels, &remoteid, ssh_channelfind);
3448 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
3449 logevent("Forwarded connection refused by server");
3450 pfd_close(c->u.pfd.s);
3451 del234(ssh->channels, c);
3452 sfree(c);
3453 }
3454
3455 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ||
3456 ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION) {
3457 /* Remote side closes a channel. */
3458 unsigned i = GET_32BIT(ssh->pktin.body);
3459 struct ssh_channel *c;
3460 c = find234(ssh->channels, &i, ssh_channelfind);
3461 if (c && ((int)c->remoteid) != -1) {
3462 int closetype;
3463 closetype =
3464 (ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ? 1 : 2);
3465
3466 if ((c->closes == 0) && (c->type == CHAN_X11)) {
3467 logevent("Forwarded X11 connection terminated");
3468 assert(c->u.x11.s != NULL);
3469 x11_close(c->u.x11.s);
3470 c->u.x11.s = NULL;
3471 }
3472 if ((c->closes == 0) && (c->type == CHAN_SOCKDATA)) {
3473 logevent("Forwarded port closed");
3474 assert(c->u.pfd.s != NULL);
3475 pfd_close(c->u.pfd.s);
3476 c->u.pfd.s = NULL;
3477 }
3478
3479 c->closes |= (closetype << 2); /* seen this message */
3480 if (!(c->closes & closetype)) {
3481 send_packet(ssh, ssh->pktin.type, PKT_INT, c->remoteid,
3482 PKT_END);
3483 c->closes |= closetype; /* sent it too */
3484 }
3485
3486 if (c->closes == 15) {
3487 del234(ssh->channels, c);
3488 sfree(c);
3489 }
3490 } else {
3491 bombout((ssh,"Received CHANNEL_CLOSE%s for %s channel %d\n",
3492 ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ? "" :
3493 "_CONFIRMATION", c ? "half-open" : "nonexistent",
3494 i));
3495 }
3496 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_DATA) {
3497 /* Data sent down one of our channels. */
3498 int i = GET_32BIT(ssh->pktin.body);
3499 int len = GET_32BIT(ssh->pktin.body + 4);
3500 unsigned char *p = ssh->pktin.body + 8;
3501 struct ssh_channel *c;
3502 c = find234(ssh->channels, &i, ssh_channelfind);
3503 if (c) {
3504 int bufsize;
3505 switch (c->type) {
3506 case CHAN_X11:
3507 bufsize = x11_send(c->u.x11.s, (char *)p, len);
3508 break;
3509 case CHAN_SOCKDATA:
3510 bufsize = pfd_send(c->u.pfd.s, (char *)p, len);
3511 break;
3512 case CHAN_AGENT:
3513 /* Data for an agent message. Buffer it. */
3514 while (len > 0) {
3515 if (c->u.a.lensofar < 4) {
3516 int l = min(4 - c->u.a.lensofar, len);
3517 memcpy(c->u.a.msglen + c->u.a.lensofar, p,
3518 l);
3519 p += l;
3520 len -= l;
3521 c->u.a.lensofar += l;
3522 }
3523 if (c->u.a.lensofar == 4) {
3524 c->u.a.totallen =
3525 4 + GET_32BIT(c->u.a.msglen);
3526 c->u.a.message = smalloc(c->u.a.totallen);
3527 memcpy(c->u.a.message, c->u.a.msglen, 4);
3528 }
3529 if (c->u.a.lensofar >= 4 && len > 0) {
3530 int l =
3531 min(c->u.a.totallen - c->u.a.lensofar,
3532 len);
3533 memcpy(c->u.a.message + c->u.a.lensofar, p,
3534 l);
3535 p += l;
3536 len -= l;
3537 c->u.a.lensofar += l;
3538 }
3539 if (c->u.a.lensofar == c->u.a.totallen) {
3540 void *reply, *sentreply;
3541 int replylen;
3542 agent_query(c->u.a.message,
3543 c->u.a.totallen, &reply,
3544 &replylen);
3545 if (reply)
3546 sentreply = reply;
3547 else {
3548 /* Fake SSH_AGENT_FAILURE. */
3549 sentreply = "\0\0\0\1\5";
3550 replylen = 5;
3551 }
3552 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
3553 PKT_INT, c->remoteid,
3554 PKT_INT, replylen,
3555 PKT_DATA, sentreply, replylen,
3556 PKT_END);
3557 if (reply)
3558 sfree(reply);
3559 sfree(c->u.a.message);
3560 c->u.a.lensofar = 0;
3561 }
3562 }
3563 bufsize = 0; /* agent channels never back up */
3564 break;
3565 }
3566 if (!c->v.v1.throttling && bufsize > SSH1_BUFFER_LIMIT) {
3567 c->v.v1.throttling = 1;
3568 ssh1_throttle(ssh, +1);
3569 }
3570 }
3571 } else if (ssh->pktin.type == SSH1_SMSG_SUCCESS) {
3572 /* may be from EXEC_SHELL on some servers */
3573 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3574 /* may be from EXEC_SHELL on some servers
3575 * if no pty is available or in other odd cases. Ignore */
3576 } else if (ssh->pktin.type == SSH1_SMSG_EXIT_STATUS) {
3577 char buf[100];
3578 ssh->exitcode = GET_32BIT(ssh->pktin.body);
3579 sprintf(buf, "Server sent command exit status %d",
3580 ssh->exitcode);
3581 logevent(buf);
3582 send_packet(ssh, SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
3583 /*
3584 * In case `helpful' firewalls or proxies tack
3585 * extra human-readable text on the end of the
3586 * session which we might mistake for another
3587 * encrypted packet, we close the session once
3588 * we've sent EXIT_CONFIRMATION.
3589 */
3590 ssh->state = SSH_STATE_CLOSED;
3591 crReturnV;
3592 } else {
3593 bombout((ssh,"Strange packet received: type %d", ssh->pktin.type));
3594 crReturnV;
3595 }
3596 } else {
3597 while (inlen > 0) {
3598 int len = min(inlen, 512);
3599 send_packet(ssh, SSH1_CMSG_STDIN_DATA,
3600 PKT_INT, len, PKT_DATA, in, len, PKT_END);
3601 in += len;
3602 inlen -= len;
3603 }
3604 }
3605 }
3606
3607 crFinishV;
3608 }
3609
3610 /*
3611 * Utility routine for decoding comma-separated strings in KEXINIT.
3612 */
3613 static int in_commasep_string(char *needle, char *haystack, int haylen)
3614 {
3615 int needlen;
3616 if (!needle || !haystack) /* protect against null pointers */
3617 return 0;
3618 needlen = strlen(needle);
3619 while (1) {
3620 /*
3621 * Is it at the start of the string?
3622 */
3623 if (haylen >= needlen && /* haystack is long enough */
3624 !memcmp(needle, haystack, needlen) && /* initial match */
3625 (haylen == needlen || haystack[needlen] == ',')
3626 /* either , or EOS follows */
3627 )
3628 return 1;
3629 /*
3630 * If not, search for the next comma and resume after that.
3631 * If no comma found, terminate.
3632 */
3633 while (haylen > 0 && *haystack != ',')
3634 haylen--, haystack++;
3635 if (haylen == 0)
3636 return 0;
3637 haylen--, haystack++; /* skip over comma itself */
3638 }
3639 }
3640
3641 /*
3642 * SSH2 key creation method.
3643 */
3644 static void ssh2_mkkey(Ssh ssh, Bignum K, unsigned char *H,
3645 unsigned char *sessid, char chr,
3646 unsigned char *keyspace)
3647 {
3648 SHA_State s;
3649 /* First 20 bytes. */
3650 SHA_Init(&s);
3651 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
3652 sha_mpint(&s, K);
3653 SHA_Bytes(&s, H, 20);
3654 SHA_Bytes(&s, &chr, 1);
3655 SHA_Bytes(&s, sessid, 20);
3656 SHA_Final(&s, keyspace);
3657 /* Next 20 bytes. */
3658 SHA_Init(&s);
3659 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
3660 sha_mpint(&s, K);
3661 SHA_Bytes(&s, H, 20);
3662 SHA_Bytes(&s, keyspace, 20);
3663 SHA_Final(&s, keyspace + 20);
3664 }
3665
3666 /*
3667 * Handle the SSH2 transport layer.
3668 */
3669 static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
3670 {
3671 struct do_ssh2_transport_state {
3672 int nbits, pbits, warn;
3673 Bignum p, g, e, f, K;
3674 int kex_init_value, kex_reply_value;
3675 const struct ssh_mac **maclist;
3676 int nmacs;
3677 const struct ssh2_cipher *cscipher_tobe;
3678 const struct ssh2_cipher *sccipher_tobe;
3679 const struct ssh_mac *csmac_tobe;
3680 const struct ssh_mac *scmac_tobe;
3681 const struct ssh_compress *cscomp_tobe;
3682 const struct ssh_compress *sccomp_tobe;
3683 char *hostkeydata, *sigdata, *keystr, *fingerprint;
3684 int hostkeylen, siglen;
3685 void *hkey; /* actual host key */
3686 unsigned char exchange_hash[20];
3687 int n_preferred_ciphers;
3688 const struct ssh2_ciphers *preferred_ciphers[CIPHER_MAX];
3689 const struct ssh_compress *preferred_comp;
3690 int first_kex;
3691 };
3692 crState(do_ssh2_transport_state);
3693
3694 crBegin(ssh->do_ssh2_transport_crstate);
3695
3696 s->cscipher_tobe = s->sccipher_tobe = NULL;
3697 s->csmac_tobe = s->scmac_tobe = NULL;
3698 s->cscomp_tobe = s->sccomp_tobe = NULL;
3699
3700 random_init();
3701 s->first_kex = 1;
3702
3703 {
3704 int i;
3705 /*
3706 * Set up the preferred ciphers. (NULL => warn below here)
3707 */
3708 s->n_preferred_ciphers = 0;
3709 for (i = 0; i < CIPHER_MAX; i++) {
3710 switch (ssh->cfg.ssh_cipherlist[i]) {
3711 case CIPHER_BLOWFISH:
3712 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_blowfish;
3713 break;
3714 case CIPHER_DES:
3715 if (ssh->cfg.ssh2_des_cbc) {
3716 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_des;
3717 }
3718 break;
3719 case CIPHER_3DES:
3720 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_3des;
3721 break;
3722 case CIPHER_AES:
3723 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_aes;
3724 break;
3725 case CIPHER_WARN:
3726 /* Flag for later. Don't bother if it's the last in
3727 * the list. */
3728 if (i < CIPHER_MAX - 1) {
3729 s->preferred_ciphers[s->n_preferred_ciphers++] = NULL;
3730 }
3731 break;
3732 }
3733 }
3734 }
3735
3736 /*
3737 * Set up preferred compression.
3738 */
3739 if (ssh->cfg.compression)
3740 s->preferred_comp = &ssh_zlib;
3741 else
3742 s->preferred_comp = &ssh_comp_none;
3743
3744 /*
3745 * Be prepared to work around the buggy MAC problem.
3746 */
3747 if (ssh->remote_bugs & BUG_SSH2_HMAC)
3748 s->maclist = buggymacs, s->nmacs = lenof(buggymacs);
3749 else
3750 s->maclist = macs, s->nmacs = lenof(macs);
3751
3752 begin_key_exchange:
3753 {
3754 int i, j, cipherstr_started;
3755
3756 /*
3757 * Construct and send our key exchange packet.
3758 */
3759 ssh2_pkt_init(ssh, SSH2_MSG_KEXINIT);
3760 for (i = 0; i < 16; i++)
3761 ssh2_pkt_addbyte(ssh, (unsigned char) random_byte());
3762 /* List key exchange algorithms. */
3763 ssh2_pkt_addstring_start(ssh);
3764 for (i = 0; i < lenof(kex_algs); i++) {
3765 if (kex_algs[i] == &ssh_diffiehellman_gex &&
3766 (ssh->remote_bugs & BUG_SSH2_DH_GEX))
3767 continue;
3768 ssh2_pkt_addstring_str(ssh, kex_algs[i]->name);
3769 if (i < lenof(kex_algs) - 1)
3770 ssh2_pkt_addstring_str(ssh, ",");
3771 }
3772 /* List server host key algorithms. */
3773 ssh2_pkt_addstring_start(ssh);
3774 for (i = 0; i < lenof(hostkey_algs); i++) {
3775 ssh2_pkt_addstring_str(ssh, hostkey_algs[i]->name);
3776 if (i < lenof(hostkey_algs) - 1)
3777 ssh2_pkt_addstring_str(ssh, ",");
3778 }
3779 /* List client->server encryption algorithms. */
3780 ssh2_pkt_addstring_start(ssh);
3781 cipherstr_started = 0;
3782 for (i = 0; i < s->n_preferred_ciphers; i++) {
3783 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3784 if (!c) continue; /* warning flag */
3785 for (j = 0; j < c->nciphers; j++) {
3786 if (cipherstr_started)
3787 ssh2_pkt_addstring_str(ssh, ",");
3788 ssh2_pkt_addstring_str(ssh, c->list[j]->name);
3789 cipherstr_started = 1;
3790 }
3791 }
3792 /* List server->client encryption algorithms. */
3793 ssh2_pkt_addstring_start(ssh);
3794 cipherstr_started = 0;
3795 for (i = 0; i < s->n_preferred_ciphers; i++) {
3796 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3797 if (!c) continue; /* warning flag */
3798 for (j = 0; j < c->nciphers; j++) {
3799 if (cipherstr_started)
3800 ssh2_pkt_addstring_str(ssh, ",");
3801 ssh2_pkt_addstring_str(ssh, c->list[j]->name);
3802 cipherstr_started = 1;
3803 }
3804 }
3805 /* List client->server MAC algorithms. */
3806 ssh2_pkt_addstring_start(ssh);
3807 for (i = 0; i < s->nmacs; i++) {
3808 ssh2_pkt_addstring_str(ssh, s->maclist[i]->name);
3809 if (i < s->nmacs - 1)
3810 ssh2_pkt_addstring_str(ssh, ",");
3811 }
3812 /* List server->client MAC algorithms. */
3813 ssh2_pkt_addstring_start(ssh);
3814 for (i = 0; i < s->nmacs; i++) {
3815 ssh2_pkt_addstring_str(ssh, s->maclist[i]->name);
3816 if (i < s->nmacs - 1)
3817 ssh2_pkt_addstring_str(ssh, ",");
3818 }
3819 /* List client->server compression algorithms. */
3820 ssh2_pkt_addstring_start(ssh);
3821 for (i = 0; i < lenof(compressions) + 1; i++) {
3822 const struct ssh_compress *c =
3823 i == 0 ? s->preferred_comp : compressions[i - 1];
3824 ssh2_pkt_addstring_str(ssh, c->name);
3825 if (i < lenof(compressions))
3826 ssh2_pkt_addstring_str(ssh, ",");
3827 }
3828 /* List server->client compression algorithms. */
3829 ssh2_pkt_addstring_start(ssh);
3830 for (i = 0; i < lenof(compressions) + 1; i++) {
3831 const struct ssh_compress *c =
3832 i == 0 ? s->preferred_comp : compressions[i - 1];
3833 ssh2_pkt_addstring_str(ssh, c->name);
3834 if (i < lenof(compressions))
3835 ssh2_pkt_addstring_str(ssh, ",");
3836 }
3837 /* List client->server languages. Empty list. */
3838 ssh2_pkt_addstring_start(ssh);
3839 /* List server->client languages. Empty list. */
3840 ssh2_pkt_addstring_start(ssh);
3841 /* First KEX packet does _not_ follow, because we're not that brave. */
3842 ssh2_pkt_addbool(ssh, FALSE);
3843 /* Reserved. */
3844 ssh2_pkt_adduint32(ssh, 0);
3845 }
3846
3847 ssh->exhash = ssh->exhashbase;
3848 sha_string(&ssh->exhash, ssh->pktout.data + 5, ssh->pktout.length - 5);
3849
3850 ssh2_pkt_send(ssh);
3851
3852 if (!ispkt)
3853 crWaitUntil(ispkt);
3854 if (ssh->pktin.length > 5)
3855 sha_string(&ssh->exhash, ssh->pktin.data + 5, ssh->pktin.length - 5);
3856
3857 /*
3858 * Now examine the other side's KEXINIT to see what we're up
3859 * to.
3860 */
3861 {
3862 char *str;
3863 int i, j, len;
3864
3865 if (ssh->pktin.type != SSH2_MSG_KEXINIT) {
3866 bombout((ssh,"expected key exchange packet from server"));
3867 crReturn(0);
3868 }
3869 ssh->kex = NULL;
3870 ssh->hostkey = NULL;
3871 s->cscipher_tobe = NULL;
3872 s->sccipher_tobe = NULL;
3873 s->csmac_tobe = NULL;
3874 s->scmac_tobe = NULL;
3875 s->cscomp_tobe = NULL;
3876 s->sccomp_tobe = NULL;
3877 ssh->pktin.savedpos += 16; /* skip garbage cookie */
3878 ssh2_pkt_getstring(ssh, &str, &len); /* key exchange algorithms */
3879 for (i = 0; i < lenof(kex_algs); i++) {
3880 if (kex_algs[i] == &ssh_diffiehellman_gex &&
3881 (ssh->remote_bugs & BUG_SSH2_DH_GEX))
3882 continue;
3883 if (in_commasep_string(kex_algs[i]->name, str, len)) {
3884 ssh->kex = kex_algs[i];
3885 break;
3886 }
3887 }
3888 ssh2_pkt_getstring(ssh, &str, &len); /* host key algorithms */
3889 for (i = 0; i < lenof(hostkey_algs); i++) {
3890 if (in_commasep_string(hostkey_algs[i]->name, str, len)) {
3891 ssh->hostkey = hostkey_algs[i];
3892 break;
3893 }
3894 }
3895 ssh2_pkt_getstring(ssh, &str, &len); /* client->server cipher */
3896 s->warn = 0;
3897 for (i = 0; i < s->n_preferred_ciphers; i++) {
3898 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3899 if (!c) {
3900 s->warn = 1;
3901 } else {
3902 for (j = 0; j < c->nciphers; j++) {
3903 if (in_commasep_string(c->list[j]->name, str, len)) {
3904 s->cscipher_tobe = c->list[j];
3905 break;
3906 }
3907 }
3908 }
3909 if (s->cscipher_tobe) {
3910 if (s->warn)
3911 askcipher(ssh->frontend, s->cscipher_tobe->name, 1);
3912 break;
3913 }
3914 }
3915 if (!s->cscipher_tobe) {
3916 bombout((ssh,"Couldn't agree a client-to-server cipher (available: %s)",
3917 str ? str : "(null)"));
3918 crReturn(0);
3919 }
3920
3921 ssh2_pkt_getstring(ssh, &str, &len); /* server->client cipher */
3922 s->warn = 0;
3923 for (i = 0; i < s->n_preferred_ciphers; i++) {
3924 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3925 if (!c) {
3926 s->warn = 1;
3927 } else {
3928 for (j = 0; j < c->nciphers; j++) {
3929 if (in_commasep_string(c->list[j]->name, str, len)) {
3930 s->sccipher_tobe = c->list[j];
3931 break;
3932 }
3933 }
3934 }
3935 if (s->sccipher_tobe) {
3936 if (s->warn)
3937 askcipher(ssh->frontend, s->sccipher_tobe->name, 2);
3938 break;
3939 }
3940 }
3941 if (!s->sccipher_tobe) {
3942 bombout((ssh,"Couldn't agree a server-to-client cipher (available: %s)",
3943 str ? str : "(null)"));
3944 crReturn(0);
3945 }
3946
3947 ssh2_pkt_getstring(ssh, &str, &len); /* client->server mac */
3948 for (i = 0; i < s->nmacs; i++) {
3949 if (in_commasep_string(s->maclist[i]->name, str, len)) {
3950 s->csmac_tobe = s->maclist[i];
3951 break;
3952 }
3953 }
3954 ssh2_pkt_getstring(ssh, &str, &len); /* server->client mac */
3955 for (i = 0; i < s->nmacs; i++) {
3956 if (in_commasep_string(s->maclist[i]->name, str, len)) {
3957 s->scmac_tobe = s->maclist[i];
3958 break;
3959 }
3960 }
3961 ssh2_pkt_getstring(ssh, &str, &len); /* client->server compression */
3962 for (i = 0; i < lenof(compressions) + 1; i++) {
3963 const struct ssh_compress *c =
3964 i == 0 ? s->preferred_comp : compressions[i - 1];
3965 if (in_commasep_string(c->name, str, len)) {
3966 s->cscomp_tobe = c;
3967 break;
3968 }
3969 }
3970 ssh2_pkt_getstring(ssh, &str, &len); /* server->client compression */
3971 for (i = 0; i < lenof(compressions) + 1; i++) {
3972 const struct ssh_compress *c =
3973 i == 0 ? s->preferred_comp : compressions[i - 1];
3974 if (in_commasep_string(c->name, str, len)) {
3975 s->sccomp_tobe = c;
3976 break;
3977 }
3978 }
3979 }
3980
3981 /*
3982 * Work out the number of bits of key we will need from the key
3983 * exchange. We start with the maximum key length of either
3984 * cipher...
3985 */
3986 {
3987 int csbits, scbits;
3988
3989 csbits = s->cscipher_tobe->keylen;
3990 scbits = s->sccipher_tobe->keylen;
3991 s->nbits = (csbits > scbits ? csbits : scbits);
3992 }
3993 /* The keys only have 160-bit entropy, since they're based on
3994 * a SHA-1 hash. So cap the key size at 160 bits. */
3995 if (s->nbits > 160)
3996 s->nbits = 160;
3997
3998 /*
3999 * If we're doing Diffie-Hellman group exchange, start by
4000 * requesting a group.
4001 */
4002 if (ssh->kex == &ssh_diffiehellman_gex) {
4003 logevent("Doing Diffie-Hellman group exchange");
4004 ssh->pkt_ctx |= SSH2_PKTCTX_DHGEX;
4005 /*
4006 * Work out how big a DH group we will need to allow that
4007 * much data.
4008 */
4009 s->pbits = 512 << ((s->nbits - 1) / 64);
4010 ssh2_pkt_init(ssh, SSH2_MSG_KEX_DH_GEX_REQUEST);
4011 ssh2_pkt_adduint32(ssh, s->pbits);
4012 ssh2_pkt_send(ssh);
4013
4014 crWaitUntil(ispkt);
4015 if (ssh->pktin.type != SSH2_MSG_KEX_DH_GEX_GROUP) {
4016 bombout((ssh,"expected key exchange group packet from server"));
4017 crReturn(0);
4018 }
4019 s->p = ssh2_pkt_getmp(ssh);
4020 s->g = ssh2_pkt_getmp(ssh);
4021 ssh->kex_ctx = dh_setup_group(s->p, s->g);
4022 s->kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT;
4023 s->kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY;
4024 } else {
4025 ssh->pkt_ctx |= SSH2_PKTCTX_DHGROUP1;
4026 ssh->kex_ctx = dh_setup_group1();
4027 s->kex_init_value = SSH2_MSG_KEXDH_INIT;
4028 s->kex_reply_value = SSH2_MSG_KEXDH_REPLY;
4029 }
4030
4031 logevent("Doing Diffie-Hellman key exchange");
4032 /*
4033 * Now generate and send e for Diffie-Hellman.
4034 */
4035 s->e = dh_create_e(ssh->kex_ctx, s->nbits * 2);
4036 ssh2_pkt_init(ssh, s->kex_init_value);
4037 ssh2_pkt_addmp(ssh, s->e);
4038 ssh2_pkt_send(ssh);
4039
4040 crWaitUntil(ispkt);
4041 if (ssh->pktin.type != s->kex_reply_value) {
4042 bombout((ssh,"expected key exchange reply packet from server"));
4043 crReturn(0);
4044 }
4045 ssh2_pkt_getstring(ssh, &s->hostkeydata, &s->hostkeylen);
4046 s->f = ssh2_pkt_getmp(ssh);
4047 ssh2_pkt_getstring(ssh, &s->sigdata, &s->siglen);
4048
4049 s->K = dh_find_K(ssh->kex_ctx, s->f);
4050
4051 sha_string(&ssh->exhash, s->hostkeydata, s->hostkeylen);
4052 if (ssh->kex == &ssh_diffiehellman_gex) {
4053 sha_uint32(&ssh->exhash, s->pbits);
4054 sha_mpint(&ssh->exhash, s->p);
4055 sha_mpint(&ssh->exhash, s->g);
4056 }
4057 sha_mpint(&ssh->exhash, s->e);
4058 sha_mpint(&ssh->exhash, s->f);
4059 sha_mpint(&ssh->exhash, s->K);
4060 SHA_Final(&ssh->exhash, s->exchange_hash);
4061
4062 dh_cleanup(ssh->kex_ctx);
4063 ssh->kex_ctx = NULL;
4064
4065 #if 0
4066 debug(("Exchange hash is:\n"));
4067 dmemdump(s->exchange_hash, 20);
4068 #endif
4069
4070 s->hkey = ssh->hostkey->newkey(s->hostkeydata, s->hostkeylen);
4071 if (!s->hkey ||
4072 !ssh->hostkey->verifysig(s->hkey, s->sigdata, s->siglen,
4073 (char *)s->exchange_hash, 20)) {
4074 bombout((ssh,"Server's host key did not match the signature supplied"));
4075 crReturn(0);
4076 }
4077
4078 /*
4079 * Authenticate remote host: verify host key. (We've already
4080 * checked the signature of the exchange hash.)
4081 */
4082 s->keystr = ssh->hostkey->fmtkey(s->hkey);
4083 s->fingerprint = ssh->hostkey->fingerprint(s->hkey);
4084 verify_ssh_host_key(ssh->frontend,
4085 ssh->savedhost, ssh->savedport, ssh->hostkey->keytype,
4086 s->keystr, s->fingerprint);
4087 if (s->first_kex) { /* don't bother logging this in rekeys */
4088 logevent("Host key fingerprint is:");
4089 logevent(s->fingerprint);
4090 }
4091 sfree(s->fingerprint);
4092 sfree(s->keystr);
4093 ssh->hostkey->freekey(s->hkey);
4094
4095 /*
4096 * Send SSH2_MSG_NEWKEYS.
4097 */
4098 ssh2_pkt_init(ssh, SSH2_MSG_NEWKEYS);
4099 ssh2_pkt_send(ssh);
4100
4101 /*
4102 * Expect SSH2_MSG_NEWKEYS from server.
4103 */
4104 crWaitUntil(ispkt);
4105 if (ssh->pktin.type != SSH2_MSG_NEWKEYS) {
4106 bombout((ssh,"expected new-keys packet from server"));
4107 crReturn(0);
4108 }
4109
4110 /*
4111 * Create and initialise session keys.
4112 */
4113 if (ssh->cs_cipher_ctx)
4114 ssh->cscipher->free_context(ssh->cs_cipher_ctx);
4115 ssh->cscipher = s->cscipher_tobe;
4116 ssh->cs_cipher_ctx = ssh->cscipher->make_context();
4117
4118 if (ssh->sc_cipher_ctx)
4119 ssh->sccipher->free_context(ssh->sc_cipher_ctx);
4120 ssh->sccipher = s->sccipher_tobe;
4121 ssh->sc_cipher_ctx = ssh->sccipher->make_context();
4122
4123 if (ssh->cs_mac_ctx)
4124 ssh->csmac->free_context(ssh->cs_mac_ctx);
4125 ssh->csmac = s->csmac_tobe;
4126 ssh->cs_mac_ctx = ssh->csmac->make_context();
4127
4128 if (ssh->sc_mac_ctx)
4129 ssh->scmac->free_context(ssh->sc_mac_ctx);
4130 ssh->scmac = s->scmac_tobe;
4131 ssh->sc_mac_ctx = ssh->scmac->make_context();
4132
4133 if (ssh->cs_comp_ctx)
4134 ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
4135 ssh->cscomp = s->cscomp_tobe;
4136 ssh->cs_comp_ctx = ssh->cscomp->compress_init();
4137
4138 if (ssh->sc_comp_ctx)
4139 ssh->sccomp->decompress_cleanup(ssh->sc_comp_ctx);
4140 ssh->sccomp = s->sccomp_tobe;
4141 ssh->sc_comp_ctx = ssh->sccomp->decompress_init();
4142
4143 /*
4144 * Set IVs after keys. Here we use the exchange hash from the
4145 * _first_ key exchange.
4146 */
4147 {
4148 unsigned char keyspace[40];
4149 if (s->first_kex)
4150 memcpy(ssh->v2_session_id, s->exchange_hash,
4151 sizeof(s->exchange_hash));
4152 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'C',keyspace);
4153 ssh->cscipher->setkey(ssh->cs_cipher_ctx, keyspace);
4154 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'D',keyspace);
4155 ssh->sccipher->setkey(ssh->sc_cipher_ctx, keyspace);
4156 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'A',keyspace);
4157 ssh->cscipher->setiv(ssh->cs_cipher_ctx, keyspace);
4158 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'B',keyspace);
4159 ssh->sccipher->setiv(ssh->sc_cipher_ctx, keyspace);
4160 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'E',keyspace);
4161 ssh->csmac->setkey(ssh->cs_mac_ctx, keyspace);
4162 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'F',keyspace);
4163 ssh->scmac->setkey(ssh->sc_mac_ctx, keyspace);
4164 }
4165 logeventf(ssh, "Initialised %.200s client->server encryption",
4166 ssh->cscipher->text_name);
4167 logeventf(ssh, "Initialised %.200s server->client encryption",
4168 ssh->sccipher->text_name);
4169 if (ssh->cscomp->text_name)
4170 logeventf(ssh, "Initialised %s compression",
4171 ssh->cscomp->text_name);
4172 if (ssh->sccomp->text_name)
4173 logeventf(ssh, "Initialised %s decompression",
4174 ssh->sccomp->text_name);
4175
4176 /*
4177 * If this is the first key exchange phase, we must pass the
4178 * SSH2_MSG_NEWKEYS packet to the next layer, not because it
4179 * wants to see it but because it will need time to initialise
4180 * itself before it sees an actual packet. In subsequent key
4181 * exchange phases, we don't pass SSH2_MSG_NEWKEYS on, because
4182 * it would only confuse the layer above.
4183 */
4184 if (!s->first_kex) {
4185 crReturn(0);
4186 }
4187 s->first_kex = 0;
4188
4189 /*
4190 * Now we're encrypting. Begin returning 1 to the protocol main
4191 * function so that other things can run on top of the
4192 * transport. If we ever see a KEXINIT, we must go back to the
4193 * start.
4194 */
4195 while (!(ispkt && ssh->pktin.type == SSH2_MSG_KEXINIT)) {
4196 crReturn(1);
4197 }
4198 logevent("Server initiated key re-exchange");
4199 goto begin_key_exchange;
4200
4201 crFinish(1);
4202 }
4203
4204 /*
4205 * Add data to an SSH2 channel output buffer.
4206 */
4207 static void ssh2_add_channel_data(struct ssh_channel *c, char *buf,
4208 int len)
4209 {
4210 bufchain_add(&c->v.v2.outbuffer, buf, len);
4211 }
4212
4213 /*
4214 * Attempt to send data on an SSH2 channel.
4215 */
4216 static int ssh2_try_send(struct ssh_channel *c)
4217 {
4218 Ssh ssh = c->ssh;
4219
4220 while (c->v.v2.remwindow > 0 && bufchain_size(&c->v.v2.outbuffer) > 0) {
4221 int len;
4222 void *data;
4223 bufchain_prefix(&c->v.v2.outbuffer, &data, &len);
4224 if ((unsigned)len > c->v.v2.remwindow)
4225 len = c->v.v2.remwindow;
4226 if ((unsigned)len > c->v.v2.remmaxpkt)
4227 len = c->v.v2.remmaxpkt;
4228 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_DATA);
4229 ssh2_pkt_adduint32(ssh, c->remoteid);
4230 ssh2_pkt_addstring_start(ssh);
4231 ssh2_pkt_addstring_data(ssh, data, len);
4232 ssh2_pkt_send(ssh);
4233 bufchain_consume(&c->v.v2.outbuffer, len);
4234 c->v.v2.remwindow -= len;
4235 }
4236
4237 /*
4238 * After having sent as much data as we can, return the amount
4239 * still buffered.
4240 */
4241 return bufchain_size(&c->v.v2.outbuffer);
4242 }
4243
4244 /*
4245 * Potentially enlarge the window on an SSH2 channel.
4246 */
4247 static void ssh2_set_window(struct ssh_channel *c, unsigned newwin)
4248 {
4249 Ssh ssh = c->ssh;
4250
4251 /*
4252 * Never send WINDOW_ADJUST for a channel that the remote side
4253 * already thinks it's closed; there's no point, since it won't
4254 * be sending any more data anyway.
4255 */
4256 if (c->closes != 0)
4257 return;
4258
4259 if (newwin > c->v.v2.locwindow) {
4260 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST);
4261 ssh2_pkt_adduint32(ssh, c->remoteid);
4262 ssh2_pkt_adduint32(ssh, newwin - c->v.v2.locwindow);
4263 ssh2_pkt_send(ssh);
4264 c->v.v2.locwindow = newwin;
4265 }
4266 }
4267
4268 /*
4269 * Handle the SSH2 userauth and connection layers.
4270 */
4271 static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
4272 {
4273 struct do_ssh2_authconn_state {
4274 enum {
4275 AUTH_INVALID, AUTH_PUBLICKEY_AGENT, AUTH_PUBLICKEY_FILE,
4276 AUTH_PASSWORD,
4277 AUTH_KEYBOARD_INTERACTIVE
4278 } method;
4279 enum {
4280 AUTH_TYPE_NONE,
4281 AUTH_TYPE_PUBLICKEY,
4282 AUTH_TYPE_PUBLICKEY_OFFER_LOUD,
4283 AUTH_TYPE_PUBLICKEY_OFFER_QUIET,
4284 AUTH_TYPE_PASSWORD,
4285 AUTH_TYPE_KEYBOARD_INTERACTIVE,
4286 AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET
4287 } type;
4288 int gotit, need_pw, can_pubkey, can_passwd, can_keyb_inter;
4289 int tried_pubkey_config, tried_agent, tried_keyb_inter;
4290 int kbd_inter_running;
4291 int we_are_in;
4292 int num_prompts, curr_prompt, echo;
4293 char username[100];
4294 int got_username;
4295 char pwprompt[200];
4296 char password[100];
4297 void *publickey_blob;
4298 int publickey_bloblen;
4299 unsigned char request[5], *response, *p;
4300 int responselen;
4301 int keyi, nkeys;
4302 int authed;
4303 char *pkblob, *alg, *commentp;
4304 int pklen, alglen, commentlen;
4305 int siglen, retlen, len;
4306 char *q, *agentreq, *ret;
4307 int try_send;
4308 };
4309 crState(do_ssh2_authconn_state);
4310
4311 crBegin(ssh->do_ssh2_authconn_crstate);
4312
4313 /*
4314 * Request userauth protocol, and await a response to it.
4315 */
4316 ssh2_pkt_init(ssh, SSH2_MSG_SERVICE_REQUEST);
4317 ssh2_pkt_addstring(ssh, "ssh-userauth");
4318 ssh2_pkt_send(ssh);
4319 crWaitUntilV(ispkt);
4320 if (ssh->pktin.type != SSH2_MSG_SERVICE_ACCEPT) {
4321 bombout((ssh,"Server refused user authentication protocol"));
4322 crReturnV;
4323 }
4324
4325 /*
4326 * We repeat this whole loop, including the username prompt,
4327 * until we manage a successful authentication. If the user
4328 * types the wrong _password_, they can be sent back to the
4329 * beginning to try another username, if this is configured on.
4330 * (If they specify a username in the config, they are never
4331 * asked, even if they do give a wrong password.)
4332 *
4333 * I think this best serves the needs of
4334 *
4335 * - the people who have no configuration, no keys, and just
4336 * want to try repeated (username,password) pairs until they
4337 * type both correctly
4338 *
4339 * - people who have keys and configuration but occasionally
4340 * need to fall back to passwords
4341 *
4342 * - people with a key held in Pageant, who might not have
4343 * logged in to a particular machine before; so they want to
4344 * type a username, and then _either_ their key will be
4345 * accepted, _or_ they will type a password. If they mistype
4346 * the username they will want to be able to get back and
4347 * retype it!
4348 */
4349 s->username[0] = '\0';
4350 s->got_username = FALSE;
4351 do {
4352 /*
4353 * Get a username.
4354 */
4355 if (s->got_username && !ssh->cfg.change_username) {
4356 /*
4357 * We got a username last time round this loop, and
4358 * with change_username turned off we don't try to get
4359 * it again.
4360 */
4361 } else if ((flags & FLAG_INTERACTIVE) && !*ssh->cfg.username) {
4362 if (ssh_get_line && !ssh_getline_pw_only) {
4363 if (!ssh_get_line("login as: ",
4364 s->username, sizeof(s->username), FALSE)) {
4365 /*
4366 * get_line failed to get a username.
4367 * Terminate.
4368 */
4369 logevent("No username provided. Abandoning session.");
4370 ssh->state = SSH_STATE_CLOSED;
4371 crReturnV;
4372 }
4373 } else {
4374 int ret; /* need not be saved across crReturn */
4375 c_write_str(ssh, "login as: ");
4376 ssh->send_ok = 1;
4377 setup_userpass_input(ssh, s->username, sizeof(s->username), 1);
4378 do {
4379 crWaitUntilV(!ispkt);
4380 ret = process_userpass_input(ssh, in, inlen);
4381 } while (ret == 0);
4382 if (ret < 0)
4383 cleanup_exit(0);
4384 c_write_str(ssh, "\r\n");
4385 }
4386 s->username[strcspn(s->username, "\n\r")] = '\0';
4387 } else {
4388 char *stuff;
4389 strncpy(s->username, ssh->cfg.username, sizeof(s->username));
4390 s->username[sizeof(s->username)-1] = '\0';
4391 if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
4392 stuff = dupprintf("Using username \"%s\".\r\n", s->username);
4393 c_write_str(ssh, stuff);
4394 sfree(stuff);
4395 }
4396 }
4397 s->got_username = TRUE;
4398
4399 /*
4400 * Send an authentication request using method "none": (a)
4401 * just in case it succeeds, and (b) so that we know what
4402 * authentication methods we can usefully try next.
4403 */
4404 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4405
4406 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4407 ssh2_pkt_addstring(ssh, s->username);
4408 ssh2_pkt_addstring(ssh, "ssh-connection");/* service requested */
4409 ssh2_pkt_addstring(ssh, "none"); /* method */
4410 ssh2_pkt_send(ssh);
4411 s->type = AUTH_TYPE_NONE;
4412 s->gotit = FALSE;
4413 s->we_are_in = FALSE;
4414
4415 s->tried_pubkey_config = FALSE;
4416 s->tried_agent = FALSE;
4417 s->tried_keyb_inter = FALSE;
4418 s->kbd_inter_running = FALSE;
4419 /* Load the pub half of ssh->cfg.keyfile so we notice if it's in Pageant */
4420 if (!filename_is_null(ssh->cfg.keyfile)) {
4421 int keytype;
4422 logeventf(ssh, "Reading private key file \"%.150s\"",
4423 filename_to_str(&ssh->cfg.keyfile));
4424 keytype = key_type(&ssh->cfg.keyfile);
4425 if (keytype == SSH_KEYTYPE_SSH2) {
4426 s->publickey_blob =
4427 ssh2_userkey_loadpub(&ssh->cfg.keyfile, NULL,
4428 &s->publickey_bloblen);
4429 } else {
4430 char *msgbuf;
4431 logeventf(ssh, "Unable to use this key file (%s)",
4432 key_type_to_str(keytype));
4433 msgbuf = dupprintf("Unable to use key file \"%.150s\""
4434 " (%s)\r\n",
4435 filename_to_str(&ssh->cfg.keyfile),
4436 key_type_to_str(keytype));
4437 c_write_str(ssh, msgbuf);
4438 sfree(msgbuf);
4439 s->publickey_blob = NULL;
4440 }
4441 } else
4442 s->publickey_blob = NULL;
4443
4444 while (1) {
4445 /*
4446 * Wait for the result of the last authentication request.
4447 */
4448 if (!s->gotit)
4449 crWaitUntilV(ispkt);
4450 while (ssh->pktin.type == SSH2_MSG_USERAUTH_BANNER) {
4451 char *banner;
4452 int size;
4453 /*
4454 * Don't show the banner if we're operating in
4455 * non-verbose non-interactive mode. (It's probably
4456 * a script, which means nobody will read the
4457 * banner _anyway_, and moreover the printing of
4458 * the banner will screw up processing on the
4459 * output of (say) plink.)
4460 */
4461 if (flags & (FLAG_VERBOSE | FLAG_INTERACTIVE)) {
4462 ssh2_pkt_getstring(ssh, &banner, &size);
4463 if (banner)
4464 c_write_untrusted(ssh, banner, size);
4465 }
4466 crWaitUntilV(ispkt);
4467 }
4468 if (ssh->pktin.type == SSH2_MSG_USERAUTH_SUCCESS) {
4469 logevent("Access granted");
4470 s->we_are_in = TRUE;
4471 break;
4472 }
4473
4474 if (s->kbd_inter_running &&
4475 ssh->pktin.type == SSH2_MSG_USERAUTH_INFO_REQUEST) {
4476 /*
4477 * This is either a further set-of-prompts packet
4478 * in keyboard-interactive authentication, or it's
4479 * the same one and we came back here with `gotit'
4480 * set. In the former case, we must reset the
4481 * curr_prompt variable.
4482 */
4483 if (!s->gotit)
4484 s->curr_prompt = 0;
4485 } else if (ssh->pktin.type != SSH2_MSG_USERAUTH_FAILURE) {
4486 bombout((ssh,"Strange packet received during authentication: type %d",
4487 ssh->pktin.type));
4488 crReturnV;
4489 }
4490
4491 s->gotit = FALSE;
4492
4493 /*
4494 * OK, we're now sitting on a USERAUTH_FAILURE message, so
4495 * we can look at the string in it and know what we can
4496 * helpfully try next.
4497 */
4498 if (ssh->pktin.type == SSH2_MSG_USERAUTH_FAILURE) {
4499 char *methods;
4500 int methlen;
4501 ssh2_pkt_getstring(ssh, &methods, &methlen);
4502 s->kbd_inter_running = FALSE;
4503 if (!ssh2_pkt_getbool(ssh)) {
4504 /*
4505 * We have received an unequivocal Access
4506 * Denied. This can translate to a variety of
4507 * messages:
4508 *
4509 * - if we'd just tried "none" authentication,
4510 * it's not worth printing anything at all
4511 *
4512 * - if we'd just tried a public key _offer_,
4513 * the message should be "Server refused our
4514 * key" (or no message at all if the key
4515 * came from Pageant)
4516 *
4517 * - if we'd just tried anything else, the
4518 * message really should be "Access denied".
4519 *
4520 * Additionally, if we'd just tried password
4521 * authentication, we should break out of this
4522 * whole loop so as to go back to the username
4523 * prompt.
4524 */
4525 if (s->type == AUTH_TYPE_NONE) {
4526 /* do nothing */
4527 } else if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD ||
4528 s->type == AUTH_TYPE_PUBLICKEY_OFFER_QUIET) {
4529 if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD)
4530 c_write_str(ssh, "Server refused our key\r\n");
4531 logevent("Server refused public key");
4532 } else if (s->type==AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET) {
4533 /* server declined keyboard-interactive; ignore */
4534 } else {
4535 c_write_str(ssh, "Access denied\r\n");
4536 logevent("Access denied");
4537 if (s->type == AUTH_TYPE_PASSWORD) {
4538 s->we_are_in = FALSE;
4539 break;
4540 }
4541 }
4542 } else {
4543 c_write_str(ssh, "Further authentication required\r\n");
4544 logevent("Further authentication required");
4545 }
4546
4547 s->can_pubkey =
4548 in_commasep_string("publickey", methods, methlen);
4549 s->can_passwd =
4550 in_commasep_string("password", methods, methlen);
4551 s->can_keyb_inter = ssh->cfg.try_ki_auth &&
4552 in_commasep_string("keyboard-interactive", methods, methlen);
4553 }
4554
4555 s->method = 0;
4556 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4557
4558 /*
4559 * Most password/passphrase prompts will be
4560 * non-echoing, so we set this to 0 by default.
4561 * Exception is that some keyboard-interactive prompts
4562 * can be echoing, in which case we'll set this to 1.
4563 */
4564 s->echo = 0;
4565
4566 if (!s->method && s->can_pubkey &&
4567 agent_exists() && !s->tried_agent) {
4568 /*
4569 * Attempt public-key authentication using Pageant.
4570 */
4571 void *r;
4572 s->authed = FALSE;
4573
4574 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4575 ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
4576
4577 s->tried_agent = TRUE;
4578
4579 logevent("Pageant is running. Requesting keys.");
4580
4581 /* Request the keys held by the agent. */
4582 PUT_32BIT(s->request, 1);
4583 s->request[4] = SSH2_AGENTC_REQUEST_IDENTITIES;
4584 agent_query(s->request, 5, &r, &s->responselen);
4585 s->response = (unsigned char *) r;
4586 if (s->response && s->responselen >= 5 &&
4587 s->response[4] == SSH2_AGENT_IDENTITIES_ANSWER) {
4588 s->p = s->response + 5;
4589 s->nkeys = GET_32BIT(s->p);
4590 s->p += 4;
4591 {
4592 char buf[64];
4593 sprintf(buf, "Pageant has %d SSH2 keys", s->nkeys);
4594 logevent(buf);
4595 }
4596 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
4597 void *vret;
4598
4599 {
4600 char buf[64];
4601 sprintf(buf, "Trying Pageant key #%d", s->keyi);
4602 logevent(buf);
4603 }
4604 s->pklen = GET_32BIT(s->p);
4605 s->p += 4;
4606 if (s->publickey_blob &&
4607 s->pklen == s->publickey_bloblen &&
4608 !memcmp(s->p, s->publickey_blob,
4609 s->publickey_bloblen)) {
4610 logevent("This key matches configured key file");
4611 s->tried_pubkey_config = 1;
4612 }
4613 s->pkblob = (char *)s->p;
4614 s->p += s->pklen;
4615 s->alglen = GET_32BIT(s->pkblob);
4616 s->alg = s->pkblob + 4;
4617 s->commentlen = GET_32BIT(s->p);
4618 s->p += 4;
4619 s->commentp = (char *)s->p;
4620 s->p += s->commentlen;
4621 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4622 ssh2_pkt_addstring(ssh, s->username);
4623 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4624 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4625 ssh2_pkt_addbool(ssh, FALSE); /* no signature included */
4626 ssh2_pkt_addstring_start(ssh);
4627 ssh2_pkt_addstring_data(ssh, s->alg, s->alglen);
4628 ssh2_pkt_addstring_start(ssh);
4629 ssh2_pkt_addstring_data(ssh, s->pkblob, s->pklen);
4630 ssh2_pkt_send(ssh);
4631
4632 crWaitUntilV(ispkt);
4633 if (ssh->pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
4634 logevent("Key refused");
4635 continue;
4636 }
4637
4638 if (flags & FLAG_VERBOSE) {
4639 c_write_str(ssh, "Authenticating with "
4640 "public key \"");
4641 c_write(ssh, s->commentp, s->commentlen);
4642 c_write_str(ssh, "\" from agent\r\n");
4643 }
4644
4645 /*
4646 * Server is willing to accept the key.
4647 * Construct a SIGN_REQUEST.
4648 */
4649 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4650 ssh2_pkt_addstring(ssh, s->username);
4651 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4652 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4653 ssh2_pkt_addbool(ssh, TRUE);
4654 ssh2_pkt_addstring_start(ssh);
4655 ssh2_pkt_addstring_data(ssh, s->alg, s->alglen);
4656 ssh2_pkt_addstring_start(ssh);
4657 ssh2_pkt_addstring_data(ssh, s->pkblob, s->pklen);
4658
4659 s->siglen = ssh->pktout.length - 5 + 4 + 20;
4660 if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
4661 s->siglen -= 4;
4662 s->len = 1; /* message type */
4663 s->len += 4 + s->pklen; /* key blob */
4664 s->len += 4 + s->siglen; /* data to sign */
4665 s->len += 4; /* flags */
4666 s->agentreq = smalloc(4 + s->len);
4667 PUT_32BIT(s->agentreq, s->len);
4668 s->q = s->agentreq + 4;
4669 *s->q++ = SSH2_AGENTC_SIGN_REQUEST;
4670 PUT_32BIT(s->q, s->pklen);
4671 s->q += 4;
4672 memcpy(s->q, s->pkblob, s->pklen);
4673 s->q += s->pklen;
4674 PUT_32BIT(s->q, s->siglen);
4675 s->q += 4;
4676 /* Now the data to be signed... */
4677 if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
4678 PUT_32BIT(s->q, 20);
4679 s->q += 4;
4680 }
4681 memcpy(s->q, ssh->v2_session_id, 20);
4682 s->q += 20;
4683 memcpy(s->q, ssh->pktout.data + 5,
4684 ssh->pktout.length - 5);
4685 s->q += ssh->pktout.length - 5;
4686 /* And finally the (zero) flags word. */
4687 PUT_32BIT(s->q, 0);
4688 agent_query(s->agentreq, s->len + 4, &vret, &s->retlen);
4689 s->ret = vret;
4690 sfree(s->agentreq);
4691 if (s->ret) {
4692 if (s->ret[4] == SSH2_AGENT_SIGN_RESPONSE) {
4693 logevent("Sending Pageant's response");
4694 ssh2_add_sigblob(ssh, s->pkblob, s->pklen,
4695 s->ret + 9,
4696 GET_32BIT(s->ret + 5));
4697 ssh2_pkt_send(ssh);
4698 s->authed = TRUE;
4699 break;
4700 } else {
4701 logevent
4702 ("Pageant failed to answer challenge");
4703 sfree(s->ret);
4704 }
4705 }
4706 }
4707 if (s->authed)
4708 continue;
4709 }
4710 }
4711
4712 if (!s->method && s->can_pubkey && s->publickey_blob
4713 && !s->tried_pubkey_config) {
4714 unsigned char *pub_blob;
4715 char *algorithm, *comment;
4716 int pub_blob_len;
4717
4718 s->tried_pubkey_config = TRUE;
4719
4720 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4721 ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
4722
4723 /*
4724 * Try the public key supplied in the configuration.
4725 *
4726 * First, offer the public blob to see if the server is
4727 * willing to accept it.
4728 */
4729 pub_blob =
4730 (unsigned char *)ssh2_userkey_loadpub(&ssh->cfg.keyfile,
4731 &algorithm,
4732 &pub_blob_len);
4733 if (pub_blob) {
4734 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4735 ssh2_pkt_addstring(ssh, s->username);
4736 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4737 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4738 ssh2_pkt_addbool(ssh, FALSE); /* no signature included */
4739 ssh2_pkt_addstring(ssh, algorithm);
4740 ssh2_pkt_addstring_start(ssh);
4741 ssh2_pkt_addstring_data(ssh, (char *)pub_blob,
4742 pub_blob_len);
4743 ssh2_pkt_send(ssh);
4744 logevent("Offered public key"); /* FIXME */
4745
4746 crWaitUntilV(ispkt);
4747 if (ssh->pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
4748 s->gotit = TRUE;
4749 s->type = AUTH_TYPE_PUBLICKEY_OFFER_LOUD;
4750 continue; /* key refused; give up on it */
4751 }
4752
4753 logevent("Offer of public key accepted");
4754 /*
4755 * Actually attempt a serious authentication using
4756 * the key.
4757 */
4758 if (ssh2_userkey_encrypted(&ssh->cfg.keyfile, &comment)) {
4759 sprintf(s->pwprompt,
4760 "Passphrase for key \"%.100s\": ",
4761 comment);
4762 s->need_pw = TRUE;
4763 } else {
4764 s->need_pw = FALSE;
4765 }
4766 c_write_str(ssh, "Authenticating with public key \"");
4767 c_write_str(ssh, comment);
4768 c_write_str(ssh, "\"\r\n");
4769 s->method = AUTH_PUBLICKEY_FILE;
4770 }
4771 }
4772
4773 if (!s->method && s->can_keyb_inter && !s->tried_keyb_inter) {
4774 s->method = AUTH_KEYBOARD_INTERACTIVE;
4775 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
4776 s->tried_keyb_inter = TRUE;
4777
4778 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4779 ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;
4780
4781 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4782 ssh2_pkt_addstring(ssh, s->username);
4783 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4784 ssh2_pkt_addstring(ssh, "keyboard-interactive"); /* method */
4785 ssh2_pkt_addstring(ssh, ""); /* lang */
4786 ssh2_pkt_addstring(ssh, "");
4787 ssh2_pkt_send(ssh);
4788
4789 crWaitUntilV(ispkt);
4790 if (ssh->pktin.type != SSH2_MSG_USERAUTH_INFO_REQUEST) {
4791 if (ssh->pktin.type == SSH2_MSG_USERAUTH_FAILURE)
4792 s->gotit = TRUE;
4793 logevent("Keyboard-interactive authentication refused");
4794 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET;
4795 continue;
4796 }
4797
4798 s->kbd_inter_running = TRUE;
4799 s->curr_prompt = 0;
4800 }
4801
4802 if (s->kbd_inter_running) {
4803 s->method = AUTH_KEYBOARD_INTERACTIVE;
4804 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
4805 s->tried_keyb_inter = TRUE;
4806
4807 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4808 ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;
4809
4810 if (s->curr_prompt == 0) {
4811 /*
4812 * We've got a fresh USERAUTH_INFO_REQUEST.
4813 * Display header data, and start going through
4814 * the prompts.
4815 */
4816 char *name, *inst, *lang;
4817 int name_len, inst_len, lang_len;
4818
4819 ssh2_pkt_getstring(ssh, &name, &name_len);
4820 ssh2_pkt_getstring(ssh, &inst, &inst_len);
4821 ssh2_pkt_getstring(ssh, &lang, &lang_len);
4822 if (name_len > 0) {
4823 c_write_untrusted(ssh, name, name_len);
4824 c_write_str(ssh, "\r\n");
4825 }
4826 if (inst_len > 0) {
4827 c_write_untrusted(ssh, inst, inst_len);
4828 c_write_str(ssh, "\r\n");
4829 }
4830 s->num_prompts = ssh2_pkt_getuint32(ssh);
4831 }
4832
4833 /*
4834 * If there are prompts remaining in the packet,
4835 * display one and get a response.
4836 */
4837 if (s->curr_prompt < s->num_prompts) {
4838 char *prompt;
4839 int prompt_len;
4840
4841 ssh2_pkt_getstring(ssh, &prompt, &prompt_len);
4842 if (prompt_len > 0) {
4843 strncpy(s->pwprompt, prompt, sizeof(s->pwprompt));
4844 s->pwprompt[prompt_len < sizeof(s->pwprompt) ?
4845 prompt_len : sizeof(s->pwprompt)-1] = '\0';
4846 } else {
4847 strcpy(s->pwprompt,
4848 "<server failed to send prompt>: ");
4849 }
4850 s->echo = ssh2_pkt_getbool(ssh);
4851 s->need_pw = TRUE;
4852 } else
4853 s->need_pw = FALSE;
4854 }
4855
4856 if (!s->method && s->can_passwd) {
4857 s->method = AUTH_PASSWORD;
4858 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4859 ssh->pkt_ctx |= SSH2_PKTCTX_PASSWORD;
4860 sprintf(s->pwprompt, "%.90s@%.90s's password: ", s->username,
4861 ssh->savedhost);
4862 s->need_pw = TRUE;
4863 }
4864
4865 if (s->need_pw) {
4866 if (ssh_get_line) {
4867 if (!ssh_get_line(s->pwprompt, s->password,
4868 sizeof(s->password), TRUE)) {
4869 /*
4870 * get_line failed to get a password (for
4871 * example because one was supplied on the
4872 * command line which has already failed to
4873 * work). Terminate.
4874 */
4875 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
4876 ssh2_pkt_adduint32(ssh,SSH2_DISCONNECT_BY_APPLICATION);
4877 ssh2_pkt_addstring(ssh, "No more passwords available"
4878 " to try");
4879 ssh2_pkt_addstring(ssh, "en"); /* language tag */
4880 ssh2_pkt_send(ssh);
4881 logevent("Unable to authenticate");
4882 connection_fatal(ssh->frontend,
4883 "Unable to authenticate");
4884 ssh->state = SSH_STATE_CLOSED;
4885 crReturnV;
4886 }
4887 } else {
4888 int ret; /* need not be saved across crReturn */
4889 c_write_untrusted(ssh, s->pwprompt, strlen(s->pwprompt));
4890 ssh->send_ok = 1;
4891
4892 setup_userpass_input(ssh, s->password,
4893 sizeof(s->password), s->echo);
4894 do {
4895 crWaitUntilV(!ispkt);
4896 ret = process_userpass_input(ssh, in, inlen);
4897 } while (ret == 0);
4898 if (ret < 0)
4899 cleanup_exit(0);
4900 c_write_str(ssh, "\r\n");
4901 }
4902 }
4903
4904 if (s->method == AUTH_PUBLICKEY_FILE) {
4905 /*
4906 * We have our passphrase. Now try the actual authentication.
4907 */
4908 struct ssh2_userkey *key;
4909
4910 key = ssh2_load_userkey(&ssh->cfg.keyfile, s->password);
4911 if (key == SSH2_WRONG_PASSPHRASE || key == NULL) {
4912 if (key == SSH2_WRONG_PASSPHRASE) {
4913 c_write_str(ssh, "Wrong passphrase\r\n");
4914 s->tried_pubkey_config = FALSE;
4915 } else {
4916 c_write_str(ssh, "Unable to load private key\r\n");
4917 s->tried_pubkey_config = TRUE;
4918 }
4919 /* Send a spurious AUTH_NONE to return to the top. */
4920 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4921 ssh2_pkt_addstring(ssh, s->username);
4922 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4923 ssh2_pkt_addstring(ssh, "none"); /* method */
4924 ssh2_pkt_send(ssh);
4925 s->type = AUTH_TYPE_NONE;
4926 } else {
4927 unsigned char *pkblob, *sigblob, *sigdata;
4928 int pkblob_len, sigblob_len, sigdata_len;
4929 int p;
4930
4931 /*
4932 * We have loaded the private key and the server
4933 * has announced that it's willing to accept it.
4934 * Hallelujah. Generate a signature and send it.
4935 */
4936 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4937 ssh2_pkt_addstring(ssh, s->username);
4938 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4939 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4940 ssh2_pkt_addbool(ssh, TRUE);
4941 ssh2_pkt_addstring(ssh, key->alg->name);
4942 pkblob = key->alg->public_blob(key->data, &pkblob_len);
4943 ssh2_pkt_addstring_start(ssh);
4944 ssh2_pkt_addstring_data(ssh, (char *)pkblob, pkblob_len);
4945
4946 /*
4947 * The data to be signed is:
4948 *
4949 * string session-id
4950 *
4951 * followed by everything so far placed in the
4952 * outgoing packet.
4953 */
4954 sigdata_len = ssh->pktout.length - 5 + 4 + 20;
4955 if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
4956 sigdata_len -= 4;
4957 sigdata = smalloc(sigdata_len);
4958 p = 0;
4959 if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
4960 PUT_32BIT(sigdata+p, 20);
4961 p += 4;
4962 }
4963 memcpy(sigdata+p, ssh->v2_session_id, 20); p += 20;
4964 memcpy(sigdata+p, ssh->pktout.data + 5,
4965 ssh->pktout.length - 5);
4966 p += ssh->pktout.length - 5;
4967 assert(p == sigdata_len);
4968 sigblob = key->alg->sign(key->data, (char *)sigdata,
4969 sigdata_len, &sigblob_len);
4970 ssh2_add_sigblob(ssh, pkblob, pkblob_len,
4971 sigblob, sigblob_len);
4972 sfree(pkblob);
4973 sfree(sigblob);
4974 sfree(sigdata);
4975
4976 ssh2_pkt_send(ssh);
4977 s->type = AUTH_TYPE_PUBLICKEY;
4978 }
4979 } else if (s->method == AUTH_PASSWORD) {
4980 /*
4981 * We send the password packet lumped tightly together with
4982 * an SSH_MSG_IGNORE packet. The IGNORE packet contains a
4983 * string long enough to make the total length of the two
4984 * packets constant. This should ensure that a passive
4985 * listener doing traffic analyis can't work out the length
4986 * of the password.
4987 *
4988 * For this to work, we need an assumption about the
4989 * maximum length of the password packet. I think 256 is
4990 * pretty conservative. Anyone using a password longer than
4991 * that probably doesn't have much to worry about from
4992 * people who find out how long their password is!
4993 */
4994 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4995 ssh2_pkt_addstring(ssh, s->username);
4996 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4997 ssh2_pkt_addstring(ssh, "password");
4998 ssh2_pkt_addbool(ssh, FALSE);
4999 ssh2_pkt_addstring(ssh, s->password);
5000 memset(s->password, 0, sizeof(s->password));
5001 ssh2_pkt_defer(ssh);
5002 /*
5003 * We'll include a string that's an exact multiple of the
5004 * cipher block size. If the cipher is NULL for some
5005 * reason, we don't do this trick at all because we gain
5006 * nothing by it.
5007 */
5008 if (ssh->cscipher) {
5009 int stringlen, i;
5010
5011 stringlen = (256 - ssh->deferred_len);
5012 stringlen += ssh->cscipher->blksize - 1;
5013 stringlen -= (stringlen % ssh->cscipher->blksize);
5014 if (ssh->cscomp) {
5015 /*
5016 * Temporarily disable actual compression,
5017 * so we can guarantee to get this string
5018 * exactly the length we want it. The
5019 * compression-disabling routine should
5020 * return an integer indicating how many
5021 * bytes we should adjust our string length
5022 * by.
5023 */
5024 stringlen -=
5025 ssh->cscomp->disable_compression(ssh->cs_comp_ctx);
5026 }
5027 ssh2_pkt_init(ssh, SSH2_MSG_IGNORE);
5028 ssh2_pkt_addstring_start(ssh);
5029 for (i = 0; i < stringlen; i++) {
5030 char c = (char) random_byte();
5031 ssh2_pkt_addstring_data(ssh, &c, 1);
5032 }
5033 ssh2_pkt_defer(ssh);
5034 }
5035 ssh_pkt_defersend(ssh);
5036 logevent("Sent password");
5037 s->type = AUTH_TYPE_PASSWORD;
5038 } else if (s->method == AUTH_KEYBOARD_INTERACTIVE) {
5039 if (s->curr_prompt == 0) {
5040 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_INFO_RESPONSE);
5041 ssh2_pkt_adduint32(ssh, s->num_prompts);
5042 }
5043 if (s->need_pw) { /* only add pw if we just got one! */
5044 ssh2_pkt_addstring(ssh, s->password);
5045 memset(s->password, 0, sizeof(s->password));
5046 s->curr_prompt++;
5047 }
5048 if (s->curr_prompt >= s->num_prompts) {
5049 ssh2_pkt_send(ssh);
5050 } else {
5051 /*
5052 * If there are prompts remaining, we set
5053 * `gotit' so that we won't attempt to get
5054 * another packet. Then we go back round the
5055 * loop and will end up retrieving another
5056 * prompt out of the existing packet. Funky or
5057 * what?
5058 */
5059 s->gotit = TRUE;
5060 }
5061 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
5062 } else {
5063 c_write_str(ssh, "No supported authentication methods"
5064 " left to try!\r\n");
5065 logevent("No supported authentications offered."
5066 " Disconnecting");
5067 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5068 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5069 ssh2_pkt_addstring(ssh, "No supported authentication"
5070 " methods available");
5071 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5072 ssh2_pkt_send(ssh);
5073 ssh->state = SSH_STATE_CLOSED;
5074 crReturnV;
5075 }
5076 }
5077 } while (!s->we_are_in);
5078
5079 /*
5080 * Now we're authenticated for the connection protocol. The
5081 * connection protocol will automatically have started at this
5082 * point; there's no need to send SERVICE_REQUEST.
5083 */
5084
5085 /*
5086 * So now create a channel with a session in it.
5087 */
5088 ssh->channels = newtree234(ssh_channelcmp);
5089 ssh->mainchan = smalloc(sizeof(struct ssh_channel));
5090 ssh->mainchan->ssh = ssh;
5091 ssh->mainchan->localid = alloc_channel_id(ssh);
5092 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN);
5093 ssh2_pkt_addstring(ssh, "session");
5094 ssh2_pkt_adduint32(ssh, ssh->mainchan->localid);
5095 ssh->mainchan->v.v2.locwindow = OUR_V2_WINSIZE;
5096 ssh2_pkt_adduint32(ssh, ssh->mainchan->v.v2.locwindow);/* our window size */
5097 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
5098 ssh2_pkt_send(ssh);
5099 crWaitUntilV(ispkt);
5100 if (ssh->pktin.type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
5101 bombout((ssh,"Server refused to open a session"));
5102 crReturnV;
5103 /* FIXME: error data comes back in FAILURE packet */
5104 }
5105 if (ssh2_pkt_getuint32(ssh) != ssh->mainchan->localid) {
5106 bombout((ssh,"Server's channel confirmation cited wrong channel"));
5107 crReturnV;
5108 }
5109 ssh->mainchan->remoteid = ssh2_pkt_getuint32(ssh);
5110 ssh->mainchan->type = CHAN_MAINSESSION;
5111 ssh->mainchan->closes = 0;
5112 ssh->mainchan->v.v2.remwindow = ssh2_pkt_getuint32(ssh);
5113 ssh->mainchan->v.v2.remmaxpkt = ssh2_pkt_getuint32(ssh);
5114 bufchain_init(&ssh->mainchan->v.v2.outbuffer);
5115 add234(ssh->channels, ssh->mainchan);
5116 logevent("Opened channel for session");
5117
5118 /*
5119 * Potentially enable X11 forwarding.
5120 */
5121 if (ssh->cfg.x11_forward) {
5122 char proto[20], data[64];
5123 logevent("Requesting X11 forwarding");
5124 ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
5125 data, sizeof(data), ssh->cfg.x11_auth);
5126 x11_get_real_auth(ssh->x11auth, ssh->cfg.x11_display);
5127 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5128 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
5129 ssh2_pkt_addstring(ssh, "x11-req");
5130 ssh2_pkt_addbool(ssh, 1); /* want reply */
5131 ssh2_pkt_addbool(ssh, 0); /* many connections */
5132 ssh2_pkt_addstring(ssh, proto);
5133 ssh2_pkt_addstring(ssh, data);
5134 ssh2_pkt_adduint32(ssh, x11_get_screen_number(ssh->cfg.x11_display));
5135 ssh2_pkt_send(ssh);
5136
5137 do {
5138 crWaitUntilV(ispkt);
5139 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5140 unsigned i = ssh2_pkt_getuint32(ssh);
5141 struct ssh_channel *c;
5142 c = find234(ssh->channels, &i, ssh_channelfind);
5143 if (!c)
5144 continue; /* nonexistent channel */
5145 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5146 }
5147 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5148
5149 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5150 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5151 bombout((ssh,"Unexpected response to X11 forwarding request:"
5152 " packet type %d", ssh->pktin.type));
5153 crReturnV;
5154 }
5155 logevent("X11 forwarding refused");
5156 } else {
5157 logevent("X11 forwarding enabled");
5158 ssh->X11_fwd_enabled = TRUE;
5159 }
5160 }
5161
5162 /*
5163 * Enable port forwardings.
5164 */
5165 {
5166 char type;
5167 int n;
5168 int sport,dport,sserv,dserv;
5169 char sports[256], dports[256], saddr[256], host[256];
5170
5171 ssh->rportfwds = newtree234(ssh_rportcmp_ssh2);
5172 /* Add port forwardings. */
5173 ssh->portfwd_strptr = ssh->cfg.portfwd;
5174 while (*ssh->portfwd_strptr) {
5175 type = *ssh->portfwd_strptr++;
5176 saddr[0] = '\0';
5177 n = 0;
5178 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != '\t') {
5179 if (*ssh->portfwd_strptr == ':') {
5180 /*
5181 * We've seen a colon in the middle of the
5182 * source port number. This means that
5183 * everything we've seen until now is the
5184 * source _address_, so we'll move it into
5185 * saddr and start sports from the beginning
5186 * again.
5187 */
5188 ssh->portfwd_strptr++;
5189 sports[n] = '\0';
5190 strcpy(saddr, sports);
5191 n = 0;
5192 }
5193 if (n < 255) sports[n++] = *ssh->portfwd_strptr++;
5194 }
5195 sports[n] = 0;
5196 if (*ssh->portfwd_strptr == '\t')
5197 ssh->portfwd_strptr++;
5198 n = 0;
5199 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':') {
5200 if (n < 255) host[n++] = *ssh->portfwd_strptr++;
5201 }
5202 host[n] = 0;
5203 if (*ssh->portfwd_strptr == ':')
5204 ssh->portfwd_strptr++;
5205 n = 0;
5206 while (*ssh->portfwd_strptr) {
5207 if (n < 255) dports[n++] = *ssh->portfwd_strptr++;
5208 }
5209 dports[n] = 0;
5210 ssh->portfwd_strptr++;
5211 dport = atoi(dports);
5212 dserv = 0;
5213 if (dport == 0) {
5214 dserv = 1;
5215 dport = net_service_lookup(dports);
5216 if (!dport) {
5217 logeventf(ssh, "Service lookup failed for destination"
5218 " port \"%s\"", dports);
5219 }
5220 }
5221 sport = atoi(sports);
5222 sserv = 0;
5223 if (sport == 0) {
5224 sserv = 1;
5225 sport = net_service_lookup(sports);
5226 if (!sport) {
5227 logeventf(ssh, "Service lookup failed for source"
5228 " port \"%s\"", sports);
5229 }
5230 }
5231 if (sport && dport) {
5232 if (type == 'L') {
5233 pfd_addforward(host, dport, *saddr ? saddr : NULL,
5234 sport, ssh, &ssh->cfg);
5235 logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
5236 " forwarding to %s:%.*s%.*s%d%.*s",
5237 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
5238 (int)(*saddr?1:0), ":",
5239 (int)(sserv ? strlen(sports) : 0), sports,
5240 sserv, "(", sport, sserv, ")",
5241 host,
5242 (int)(dserv ? strlen(dports) : 0), dports,
5243 dserv, "(", dport, dserv, ")");
5244 } else {
5245 struct ssh_rportfwd *pf;
5246 pf = smalloc(sizeof(*pf));
5247 strcpy(pf->dhost, host);
5248 pf->dport = dport;
5249 pf->sport = sport;
5250 if (add234(ssh->rportfwds, pf) != pf) {
5251 logeventf(ssh, "Duplicate remote port forwarding"
5252 " to %s:%d", host, dport);
5253 sfree(pf);
5254 } else {
5255 logeventf(ssh, "Requesting remote port "
5256 "%.*s%.*s%.*s%.*s%d%.*s"
5257 " forward to %s:%.*s%.*s%d%.*s",
5258 (int)(*saddr?strlen(saddr):0),
5259 *saddr?saddr:NULL,
5260 (int)(*saddr?1:0), ":",
5261 (int)(sserv ? strlen(sports) : 0), sports,
5262 sserv, "(", sport, sserv, ")",
5263 host,
5264 (int)(dserv ? strlen(dports) : 0), dports,
5265 dserv, "(", dport, dserv, ")");
5266 ssh2_pkt_init(ssh, SSH2_MSG_GLOBAL_REQUEST);
5267 ssh2_pkt_addstring(ssh, "tcpip-forward");
5268 ssh2_pkt_addbool(ssh, 1);/* want reply */
5269 if (*saddr)
5270 ssh2_pkt_addstring(ssh, saddr);
5271 if (ssh->cfg.rport_acceptall)
5272 ssh2_pkt_addstring(ssh, "0.0.0.0");
5273 else
5274 ssh2_pkt_addstring(ssh, "127.0.0.1");
5275 ssh2_pkt_adduint32(ssh, sport);
5276 ssh2_pkt_send(ssh);
5277
5278 do {
5279 crWaitUntilV(ispkt);
5280 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5281 unsigned i = ssh2_pkt_getuint32(ssh);
5282 struct ssh_channel *c;
5283 c = find234(ssh->channels, &i, ssh_channelfind);
5284 if (!c)
5285 continue;/* nonexistent channel */
5286 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5287 }
5288 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5289
5290 if (ssh->pktin.type != SSH2_MSG_REQUEST_SUCCESS) {
5291 if (ssh->pktin.type != SSH2_MSG_REQUEST_FAILURE) {
5292 bombout((ssh,"Unexpected response to port "
5293 "forwarding request: packet type %d",
5294 ssh->pktin.type));
5295 crReturnV;
5296 }
5297 logevent("Server refused this port forwarding");
5298 } else {
5299 logevent("Remote port forwarding enabled");
5300 }
5301 }
5302 }
5303 }
5304 }
5305 }
5306
5307 /*
5308 * Potentially enable agent forwarding.
5309 */
5310 if (ssh->cfg.agentfwd && agent_exists()) {
5311 logevent("Requesting OpenSSH-style agent forwarding");
5312 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5313 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
5314 ssh2_pkt_addstring(ssh, "auth-agent-req@openssh.com");
5315 ssh2_pkt_addbool(ssh, 1); /* want reply */
5316 ssh2_pkt_send(ssh);
5317
5318 do {
5319 crWaitUntilV(ispkt);
5320 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5321 unsigned i = ssh2_pkt_getuint32(ssh);
5322 struct ssh_channel *c;
5323 c = find234(ssh->channels, &i, ssh_channelfind);
5324 if (!c)
5325 continue; /* nonexistent channel */
5326 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5327 }
5328 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5329
5330 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5331 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5332 bombout((ssh,"Unexpected response to agent forwarding request:"
5333 " packet type %d", ssh->pktin.type));
5334 crReturnV;
5335 }
5336 logevent("Agent forwarding refused");
5337 } else {
5338 logevent("Agent forwarding enabled");
5339 ssh->agentfwd_enabled = TRUE;
5340 }
5341 }
5342
5343 /*
5344 * Now allocate a pty for the session.
5345 */
5346 if (!ssh->cfg.nopty) {
5347 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5348 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid); /* recipient channel */
5349 ssh2_pkt_addstring(ssh, "pty-req");
5350 ssh2_pkt_addbool(ssh, 1); /* want reply */
5351 ssh2_pkt_addstring(ssh, ssh->cfg.termtype);
5352 ssh2_pkt_adduint32(ssh, ssh->term_width);
5353 ssh2_pkt_adduint32(ssh, ssh->term_height);
5354 ssh2_pkt_adduint32(ssh, 0); /* pixel width */
5355 ssh2_pkt_adduint32(ssh, 0); /* pixel height */
5356 ssh2_pkt_addstring_start(ssh);
5357 ssh2_pkt_addstring_data(ssh, "\0", 1); /* TTY_OP_END, no special options */
5358 ssh2_pkt_send(ssh);
5359 ssh->state = SSH_STATE_INTERMED;
5360
5361 do {
5362 crWaitUntilV(ispkt);
5363 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5364 unsigned i = ssh2_pkt_getuint32(ssh);
5365 struct ssh_channel *c;
5366 c = find234(ssh->channels, &i, ssh_channelfind);
5367 if (!c)
5368 continue; /* nonexistent channel */
5369 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5370 }
5371 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5372
5373 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5374 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5375 bombout((ssh,"Unexpected response to pty request:"
5376 " packet type %d", ssh->pktin.type));
5377 crReturnV;
5378 }
5379 c_write_str(ssh, "Server refused to allocate pty\r\n");
5380 ssh->editing = ssh->echoing = 1;
5381 } else {
5382 logevent("Allocated pty");
5383 }
5384 } else {
5385 ssh->editing = ssh->echoing = 1;
5386 }
5387
5388 /*
5389 * Start a shell or a remote command. We may have to attempt
5390 * this twice if the config data has provided a second choice
5391 * of command.
5392 */
5393 while (1) {
5394 int subsys;
5395 char *cmd;
5396
5397 if (ssh->fallback_cmd) {
5398 subsys = ssh->cfg.ssh_subsys2;
5399 cmd = ssh->cfg.remote_cmd_ptr2;
5400 } else {
5401 subsys = ssh->cfg.ssh_subsys;
5402 cmd = ssh->cfg.remote_cmd_ptr;
5403 }
5404
5405 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5406 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid); /* recipient channel */
5407 if (subsys) {
5408 ssh2_pkt_addstring(ssh, "subsystem");
5409 ssh2_pkt_addbool(ssh, 1); /* want reply */
5410 ssh2_pkt_addstring(ssh, cmd);
5411 } else if (*cmd) {
5412 ssh2_pkt_addstring(ssh, "exec");
5413 ssh2_pkt_addbool(ssh, 1); /* want reply */
5414 ssh2_pkt_addstring(ssh, cmd);
5415 } else {
5416 ssh2_pkt_addstring(ssh, "shell");
5417 ssh2_pkt_addbool(ssh, 1); /* want reply */
5418 }
5419 ssh2_pkt_send(ssh);
5420 do {
5421 crWaitUntilV(ispkt);
5422 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5423 unsigned i = ssh2_pkt_getuint32(ssh);
5424 struct ssh_channel *c;
5425 c = find234(ssh->channels, &i, ssh_channelfind);
5426 if (!c)
5427 continue; /* nonexistent channel */
5428 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5429 }
5430 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5431 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5432 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5433 bombout((ssh,"Unexpected response to shell/command request:"
5434 " packet type %d", ssh->pktin.type));
5435 crReturnV;
5436 }
5437 /*
5438 * We failed to start the command. If this is the
5439 * fallback command, we really are finished; if it's
5440 * not, and if the fallback command exists, try falling
5441 * back to it before complaining.
5442 */
5443 if (!ssh->fallback_cmd && ssh->cfg.remote_cmd_ptr2 != NULL) {
5444 logevent("Primary command failed; attempting fallback");
5445 ssh->fallback_cmd = TRUE;
5446 continue;
5447 }
5448 bombout((ssh,"Server refused to start a shell/command"));
5449 crReturnV;
5450 } else {
5451 logevent("Started a shell/command");
5452 }
5453 break;
5454 }
5455
5456 ssh->state = SSH_STATE_SESSION;
5457 if (ssh->size_needed)
5458 ssh_size(ssh, ssh->term_width, ssh->term_height);
5459 if (ssh->eof_needed)
5460 ssh_special(ssh, TS_EOF);
5461
5462 /*
5463 * Transfer data!
5464 */
5465 if (ssh->ldisc)
5466 ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */
5467 ssh->send_ok = 1;
5468 while (1) {
5469 crReturnV;
5470 s->try_send = FALSE;
5471 if (ispkt) {
5472 if (ssh->pktin.type == SSH2_MSG_CHANNEL_DATA ||
5473 ssh->pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA) {
5474 char *data;
5475 int length;
5476 unsigned i = ssh2_pkt_getuint32(ssh);
5477 struct ssh_channel *c;
5478 c = find234(ssh->channels, &i, ssh_channelfind);
5479 if (!c)
5480 continue; /* nonexistent channel */
5481 if (ssh->pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
5482 ssh2_pkt_getuint32(ssh) != SSH2_EXTENDED_DATA_STDERR)
5483 continue; /* extended but not stderr */
5484 ssh2_pkt_getstring(ssh, &data, &length);
5485 if (data) {
5486 int bufsize;
5487 c->v.v2.locwindow -= length;
5488 switch (c->type) {
5489 case CHAN_MAINSESSION:
5490 bufsize =
5491 from_backend(ssh->frontend, ssh->pktin.type ==
5492 SSH2_MSG_CHANNEL_EXTENDED_DATA,
5493 data, length);
5494 break;
5495 case CHAN_X11:
5496 bufsize = x11_send(c->u.x11.s, data, length);
5497 break;
5498 case CHAN_SOCKDATA:
5499 bufsize = pfd_send(c->u.pfd.s, data, length);
5500 break;
5501 case CHAN_AGENT:
5502 while (length > 0) {
5503 if (c->u.a.lensofar < 4) {
5504 int l = min(4 - c->u.a.lensofar, length);
5505 memcpy(c->u.a.msglen + c->u.a.lensofar,
5506 data, l);
5507 data += l;
5508 length -= l;
5509 c->u.a.lensofar += l;
5510 }
5511 if (c->u.a.lensofar == 4) {
5512 c->u.a.totallen =
5513 4 + GET_32BIT(c->u.a.msglen);
5514 c->u.a.message = smalloc(c->u.a.totallen);
5515 memcpy(c->u.a.message, c->u.a.msglen, 4);
5516 }
5517 if (c->u.a.lensofar >= 4 && length > 0) {
5518 int l =
5519 min(c->u.a.totallen - c->u.a.lensofar,
5520 length);
5521 memcpy(c->u.a.message + c->u.a.lensofar,
5522 data, l);
5523 data += l;
5524 length -= l;
5525 c->u.a.lensofar += l;
5526 }
5527 if (c->u.a.lensofar == c->u.a.totallen) {
5528 void *reply, *sentreply;
5529 int replylen;
5530 agent_query(c->u.a.message,
5531 c->u.a.totallen, &reply,
5532 &replylen);
5533 if (reply)
5534 sentreply = reply;
5535 else {
5536 /* Fake SSH_AGENT_FAILURE. */
5537 sentreply = "\0\0\0\1\5";
5538 replylen = 5;
5539 }
5540 ssh2_add_channel_data(c, sentreply, replylen);
5541 s->try_send = TRUE;
5542 if (reply)
5543 sfree(reply);
5544 sfree(c->u.a.message);
5545 c->u.a.lensofar = 0;
5546 }
5547 }
5548 bufsize = 0;
5549 break;
5550 }
5551 /*
5552 * If we are not buffering too much data,
5553 * enlarge the window again at the remote side.
5554 */
5555 if (bufsize < OUR_V2_WINSIZE)
5556 ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
5557 }
5558 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_EOF) {
5559 unsigned i = ssh2_pkt_getuint32(ssh);
5560 struct ssh_channel *c;
5561
5562 c = find234(ssh->channels, &i, ssh_channelfind);
5563 if (!c)
5564 continue; /* nonexistent channel */
5565
5566 if (c->type == CHAN_X11) {
5567 /*
5568 * Remote EOF on an X11 channel means we should
5569 * wrap up and close the channel ourselves.
5570 */
5571 x11_close(c->u.x11.s);
5572 sshfwd_close(c);
5573 } else if (c->type == CHAN_AGENT) {
5574 sshfwd_close(c);
5575 } else if (c->type == CHAN_SOCKDATA) {
5576 pfd_close(c->u.pfd.s);
5577 sshfwd_close(c);
5578 }
5579 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_CLOSE) {
5580 unsigned i = ssh2_pkt_getuint32(ssh);
5581 struct ssh_channel *c;
5582
5583 c = find234(ssh->channels, &i, ssh_channelfind);
5584 if (!c || ((int)c->remoteid) == -1) {
5585 bombout((ssh,"Received CHANNEL_CLOSE for %s channel %d\n",
5586 c ? "half-open" : "nonexistent", i));
5587 }
5588 /* Do pre-close processing on the channel. */
5589 switch (c->type) {
5590 case CHAN_MAINSESSION:
5591 break; /* nothing to see here, move along */
5592 case CHAN_X11:
5593 if (c->u.x11.s != NULL)
5594 x11_close(c->u.x11.s);
5595 sshfwd_close(c);
5596 break;
5597 case CHAN_AGENT:
5598 sshfwd_close(c);
5599 break;
5600 case CHAN_SOCKDATA:
5601 if (c->u.pfd.s != NULL)
5602 pfd_close(c->u.pfd.s);
5603 sshfwd_close(c);
5604 break;
5605 }
5606 if (c->closes == 0) {
5607 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
5608 ssh2_pkt_adduint32(ssh, c->remoteid);
5609 ssh2_pkt_send(ssh);
5610 }
5611 del234(ssh->channels, c);
5612 bufchain_clear(&c->v.v2.outbuffer);
5613 sfree(c);
5614
5615 /*
5616 * See if that was the last channel left open.
5617 */
5618 if (count234(ssh->channels) == 0) {
5619 #if 0
5620 /*
5621 * We used to send SSH_MSG_DISCONNECT here,
5622 * because I'd believed that _every_ conforming
5623 * SSH2 connection had to end with a disconnect
5624 * being sent by at least one side; apparently
5625 * I was wrong and it's perfectly OK to
5626 * unceremoniously slam the connection shut
5627 * when you're done, and indeed OpenSSH feels
5628 * this is more polite than sending a
5629 * DISCONNECT. So now we don't.
5630 */
5631 logevent("All channels closed. Disconnecting");
5632 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5633 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5634 ssh2_pkt_addstring(ssh, "All open channels closed");
5635 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5636 ssh2_pkt_send(ssh);
5637 #endif
5638 ssh->state = SSH_STATE_CLOSED;
5639 crReturnV;
5640 }
5641 continue; /* remote sends close; ignore (FIXME) */
5642 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5643 unsigned i = ssh2_pkt_getuint32(ssh);
5644 struct ssh_channel *c;
5645 c = find234(ssh->channels, &i, ssh_channelfind);
5646 if (!c || c->closes)
5647 continue; /* nonexistent or closing channel */
5648 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5649 s->try_send = TRUE;
5650 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
5651 unsigned i = ssh2_pkt_getuint32(ssh);
5652 struct ssh_channel *c;
5653 c = find234(ssh->channels, &i, ssh_channelfind);
5654 if (!c)
5655 continue; /* nonexistent channel */
5656 if (c->type != CHAN_SOCKDATA_DORMANT)
5657 continue; /* dunno why they're confirming this */
5658 c->remoteid = ssh2_pkt_getuint32(ssh);
5659 c->type = CHAN_SOCKDATA;
5660 c->v.v2.remwindow = ssh2_pkt_getuint32(ssh);
5661 c->v.v2.remmaxpkt = ssh2_pkt_getuint32(ssh);
5662 if (c->u.pfd.s)
5663 pfd_confirm(c->u.pfd.s);
5664 if (c->closes) {
5665 /*
5666 * We have a pending close on this channel,
5667 * which we decided on before the server acked
5668 * the channel open. So now we know the
5669 * remoteid, we can close it again.
5670 */
5671 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
5672 ssh2_pkt_adduint32(ssh, c->remoteid);
5673 ssh2_pkt_send(ssh);
5674 }
5675 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN_FAILURE) {
5676 unsigned i = ssh2_pkt_getuint32(ssh);
5677 struct ssh_channel *c;
5678 c = find234(ssh->channels, &i, ssh_channelfind);
5679 if (!c)
5680 continue; /* nonexistent channel */
5681 if (c->type != CHAN_SOCKDATA_DORMANT)
5682 continue; /* dunno why they're failing this */
5683
5684 logevent("Forwarded connection refused by server");
5685
5686 pfd_close(c->u.pfd.s);
5687
5688 del234(ssh->channels, c);
5689 sfree(c);
5690 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_REQUEST) {
5691 unsigned localid;
5692 char *type;
5693 int typelen, want_reply;
5694 struct ssh_channel *c;
5695
5696 localid = ssh2_pkt_getuint32(ssh);
5697 ssh2_pkt_getstring(ssh, &type, &typelen);
5698 want_reply = ssh2_pkt_getbool(ssh);
5699
5700 /*
5701 * First, check that the channel exists. Otherwise,
5702 * we can instantly disconnect with a rude message.
5703 */
5704 c = find234(ssh->channels, &localid, ssh_channelfind);
5705 if (!c) {
5706 char buf[80];
5707 sprintf(buf, "Received channel request for nonexistent"
5708 " channel %d", localid);
5709 logevent(buf);
5710 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5711 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5712 ssh2_pkt_addstring(ssh, buf);
5713 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5714 ssh2_pkt_send(ssh);
5715 connection_fatal("%s", buf);
5716 ssh->state = SSH_STATE_CLOSED;
5717 crReturnV;
5718 }
5719
5720 /*
5721 * Having got the channel number, we now look at
5722 * the request type string to see if it's something
5723 * we recognise.
5724 */
5725 if (typelen == 11 && !memcmp(type, "exit-status", 11) &&
5726 c == ssh->mainchan) {
5727 /* We recognise "exit-status" on the primary channel. */
5728 char buf[100];
5729 ssh->exitcode = ssh2_pkt_getuint32(ssh);
5730 sprintf(buf, "Server sent command exit status %d",
5731 ssh->exitcode);
5732 logevent(buf);
5733 if (want_reply) {
5734 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_SUCCESS);
5735 ssh2_pkt_adduint32(ssh, c->remoteid);
5736 ssh2_pkt_send(ssh);
5737 }
5738 } else {
5739 /*
5740 * This is a channel request we don't know
5741 * about, so we now either ignore the request
5742 * or respond with CHANNEL_FAILURE, depending
5743 * on want_reply.
5744 */
5745 if (want_reply) {
5746 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_FAILURE);
5747 ssh2_pkt_adduint32(ssh, c->remoteid);
5748 ssh2_pkt_send(ssh);
5749 }
5750 }
5751 } else if (ssh->pktin.type == SSH2_MSG_GLOBAL_REQUEST) {
5752 char *type;
5753 int typelen, want_reply;
5754
5755 ssh2_pkt_getstring(ssh, &type, &typelen);
5756 want_reply = ssh2_pkt_getbool(ssh);
5757
5758 /*
5759 * We currently don't support any global requests
5760 * at all, so we either ignore the request or
5761 * respond with REQUEST_FAILURE, depending on
5762 * want_reply.
5763 */
5764 if (want_reply) {
5765 ssh2_pkt_init(ssh, SSH2_MSG_REQUEST_FAILURE);
5766 ssh2_pkt_send(ssh);
5767 }
5768 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN) {
5769 char *type;
5770 int typelen;
5771 char *peeraddr;
5772 int peeraddrlen;
5773 int port;
5774 char *error = NULL;
5775 struct ssh_channel *c;
5776 unsigned remid, winsize, pktsize;
5777 ssh2_pkt_getstring(ssh, &type, &typelen);
5778 c = smalloc(sizeof(struct ssh_channel));
5779 c->ssh = ssh;
5780
5781 remid = ssh2_pkt_getuint32(ssh);
5782 winsize = ssh2_pkt_getuint32(ssh);
5783 pktsize = ssh2_pkt_getuint32(ssh);
5784 ssh2_pkt_getstring(ssh, &peeraddr, &peeraddrlen);
5785 port = ssh2_pkt_getuint32(ssh);
5786
5787 if (typelen == 3 && !memcmp(type, "x11", 3)) {
5788 char *addrstr = smalloc(peeraddrlen+1);
5789 memcpy(addrstr, peeraddr, peeraddrlen);
5790 peeraddr[peeraddrlen] = '\0';
5791
5792 if (!ssh->X11_fwd_enabled)
5793 error = "X11 forwarding is not enabled";
5794 else if (x11_init(&c->u.x11.s, ssh->cfg.x11_display, c,
5795 ssh->x11auth, addrstr, port,
5796 &ssh->cfg) != NULL) {
5797 error = "Unable to open an X11 connection";
5798 } else {
5799 c->type = CHAN_X11;
5800 }
5801
5802 sfree(addrstr);
5803 } else if (typelen == 15 &&
5804 !memcmp(type, "forwarded-tcpip", 15)) {
5805 struct ssh_rportfwd pf, *realpf;
5806 char *dummy;
5807 int dummylen;
5808 ssh2_pkt_getstring(ssh, &dummy, &dummylen);/* skip address */
5809 pf.sport = ssh2_pkt_getuint32(ssh);
5810 realpf = find234(ssh->rportfwds, &pf, NULL);
5811 if (realpf == NULL) {
5812 error = "Remote port is not recognised";
5813 } else {
5814 char *e = pfd_newconnect(&c->u.pfd.s, realpf->dhost,
5815 realpf->dport, c, &ssh->cfg);
5816 logeventf(ssh, "Received remote port open request"
5817 " for %s:%d", realpf->dhost, realpf->dport);
5818 if (e != NULL) {
5819 logeventf(ssh, "Port open failed: %s", e);
5820 error = "Port open failed";
5821 } else {
5822 logevent("Forwarded port opened successfully");
5823 c->type = CHAN_SOCKDATA;
5824 }
5825 }
5826 } else if (typelen == 22 &&
5827 !memcmp(type, "auth-agent@openssh.com", 3)) {
5828 if (!ssh->agentfwd_enabled)
5829 error = "Agent forwarding is not enabled";
5830 else {
5831 c->type = CHAN_AGENT; /* identify channel type */
5832 c->u.a.lensofar = 0;
5833 }
5834 } else {
5835 error = "Unsupported channel type requested";
5836 }
5837
5838 c->remoteid = remid;
5839 if (error) {
5840 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN_FAILURE);
5841 ssh2_pkt_adduint32(ssh, c->remoteid);
5842 ssh2_pkt_adduint32(ssh, SSH2_OPEN_CONNECT_FAILED);
5843 ssh2_pkt_addstring(ssh, error);
5844 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5845 ssh2_pkt_send(ssh);
5846 sfree(c);
5847 } else {
5848 c->localid = alloc_channel_id(ssh);
5849 c->closes = 0;
5850 c->v.v2.locwindow = OUR_V2_WINSIZE;
5851 c->v.v2.remwindow = winsize;
5852 c->v.v2.remmaxpkt = pktsize;
5853 bufchain_init(&c->v.v2.outbuffer);
5854 add234(ssh->channels, c);
5855 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
5856 ssh2_pkt_adduint32(ssh, c->remoteid);
5857 ssh2_pkt_adduint32(ssh, c->localid);
5858 ssh2_pkt_adduint32(ssh, c->v.v2.locwindow);
5859 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
5860 ssh2_pkt_send(ssh);
5861 }
5862 } else {
5863 bombout((ssh,"Strange packet received: type %d", ssh->pktin.type));
5864 crReturnV;
5865 }
5866 } else {
5867 /*
5868 * We have spare data. Add it to the channel buffer.
5869 */
5870 ssh2_add_channel_data(ssh->mainchan, (char *)in, inlen);
5871 s->try_send = TRUE;
5872 }
5873 if (s->try_send) {
5874 int i;
5875 struct ssh_channel *c;
5876 /*
5877 * Try to send data on all channels if we can.
5878 */
5879 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
5880 int bufsize;
5881 if (c->closes)
5882 continue; /* don't send on closing channels */
5883 bufsize = ssh2_try_send(c);
5884 if (bufsize == 0) {
5885 switch (c->type) {
5886 case CHAN_MAINSESSION:
5887 /* stdin need not receive an unthrottle
5888 * notification since it will be polled */
5889 break;
5890 case CHAN_X11:
5891 x11_unthrottle(c->u.x11.s);
5892 break;
5893 case CHAN_AGENT:
5894 /* agent sockets are request/response and need no
5895 * buffer management */
5896 break;
5897 case CHAN_SOCKDATA:
5898 pfd_unthrottle(c->u.pfd.s);
5899 break;
5900 }
5901 }
5902 }
5903 }
5904 }
5905
5906 crFinishV;
5907 }
5908
5909 /*
5910 * Handle the top-level SSH2 protocol.
5911 */
5912 static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
5913 {
5914 if (do_ssh2_transport(ssh, in, inlen, ispkt) == 0)
5915 return;
5916 do_ssh2_authconn(ssh, in, inlen, ispkt);
5917 }
5918
5919 /*
5920 * Called to set up the connection.
5921 *
5922 * Returns an error message, or NULL on success.
5923 */
5924 static char *ssh_init(void *frontend_handle, void **backend_handle,
5925 Config *cfg,
5926 char *host, int port, char **realhost, int nodelay)
5927 {
5928 char *p;
5929 Ssh ssh;
5930
5931 ssh = smalloc(sizeof(*ssh));
5932 ssh->cfg = *cfg; /* STRUCTURE COPY */
5933 ssh->s = NULL;
5934 ssh->cipher = NULL;
5935 ssh->v1_cipher_ctx = NULL;
5936 ssh->crcda_ctx = NULL;
5937 ssh->cscipher = NULL;
5938 ssh->cs_cipher_ctx = NULL;
5939 ssh->sccipher = NULL;
5940 ssh->sc_cipher_ctx = NULL;
5941 ssh->csmac = NULL;
5942 ssh->cs_mac_ctx = NULL;
5943 ssh->scmac = NULL;
5944 ssh->sc_mac_ctx = NULL;
5945 ssh->cscomp = NULL;
5946 ssh->cs_comp_ctx = NULL;
5947 ssh->sccomp = NULL;
5948 ssh->sc_comp_ctx = NULL;
5949 ssh->kex = NULL;
5950 ssh->kex_ctx = NULL;
5951 ssh->hostkey = NULL;
5952 ssh->exitcode = -1;
5953 ssh->state = SSH_STATE_PREPACKET;
5954 ssh->size_needed = FALSE;
5955 ssh->eof_needed = FALSE;
5956 ssh->ldisc = NULL;
5957 ssh->logctx = NULL;
5958 {
5959 static const struct Packet empty = { 0, 0, NULL, NULL, 0 };
5960 ssh->pktin = ssh->pktout = empty;
5961 }
5962 ssh->deferred_send_data = NULL;
5963 ssh->deferred_len = 0;
5964 ssh->deferred_size = 0;
5965 ssh->fallback_cmd = 0;
5966 ssh->pkt_ctx = 0;
5967 ssh->x11auth = NULL;
5968 ssh->v1_compressing = FALSE;
5969 ssh->v2_outgoing_sequence = 0;
5970 ssh->ssh1_rdpkt_crstate = 0;
5971 ssh->ssh2_rdpkt_crstate = 0;
5972 ssh->do_ssh_init_crstate = 0;
5973 ssh->ssh_gotdata_crstate = 0;
5974 ssh->ssh1_protocol_crstate = 0;
5975 ssh->do_ssh1_login_crstate = 0;
5976 ssh->do_ssh2_transport_crstate = 0;
5977 ssh->do_ssh2_authconn_crstate = 0;
5978 ssh->do_ssh_init_state = NULL;
5979 ssh->do_ssh1_login_state = NULL;
5980 ssh->do_ssh2_transport_state = NULL;
5981 ssh->do_ssh2_authconn_state = NULL;
5982 ssh->mainchan = NULL;
5983 ssh->throttled_all = 0;
5984 ssh->v1_stdout_throttling = 0;
5985
5986 *backend_handle = ssh;
5987
5988 #ifdef MSCRYPTOAPI
5989 if (crypto_startup() == 0)
5990 return "Microsoft high encryption pack not installed!";
5991 #endif
5992
5993 ssh->frontend = frontend_handle;
5994 ssh->term_width = ssh->cfg.width;
5995 ssh->term_height = ssh->cfg.height;
5996
5997 ssh->channels = NULL;
5998 ssh->rportfwds = NULL;
5999
6000 ssh->send_ok = 0;
6001 ssh->editing = 0;
6002 ssh->echoing = 0;
6003 ssh->v1_throttle_count = 0;
6004 ssh->overall_bufsize = 0;
6005 ssh->fallback_cmd = 0;
6006
6007 ssh->protocol = NULL;
6008
6009 p = connect_to_host(ssh, host, port, realhost, nodelay);
6010 if (p != NULL)
6011 return p;
6012
6013 return NULL;
6014 }
6015
6016 static void ssh_free(void *handle)
6017 {
6018 Ssh ssh = (Ssh) handle;
6019 struct ssh_channel *c;
6020 struct ssh_rportfwd *pf;
6021
6022 if (ssh->v1_cipher_ctx)
6023 ssh->cipher->free_context(ssh->v1_cipher_ctx);
6024 if (ssh->cs_cipher_ctx)
6025 ssh->cscipher->free_context(ssh->cs_cipher_ctx);
6026 if (ssh->sc_cipher_ctx)
6027 ssh->sccipher->free_context(ssh->sc_cipher_ctx);
6028 if (ssh->cs_mac_ctx)
6029 ssh->csmac->free_context(ssh->cs_mac_ctx);
6030 if (ssh->sc_mac_ctx)
6031 ssh->scmac->free_context(ssh->sc_mac_ctx);
6032 if (ssh->cs_comp_ctx)
6033 ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
6034 if (ssh->sc_comp_ctx)
6035 ssh->sccomp->compress_cleanup(ssh->sc_comp_ctx);
6036 if (ssh->kex_ctx)
6037 dh_cleanup(ssh->kex_ctx);
6038 sfree(ssh->savedhost);
6039
6040 if (ssh->channels) {
6041 while ((c = delpos234(ssh->channels, 0)) != NULL) {
6042 switch (c->type) {
6043 case CHAN_X11:
6044 if (c->u.x11.s != NULL)
6045 x11_close(c->u.x11.s);
6046 break;
6047 case CHAN_SOCKDATA:
6048 if (c->u.pfd.s != NULL)
6049 pfd_close(c->u.pfd.s);
6050 break;
6051 }
6052 sfree(c);
6053 }
6054 freetree234(ssh->channels);
6055 }
6056
6057 if (ssh->rportfwds) {
6058 while ((pf = delpos234(ssh->rportfwds, 0)) != NULL)
6059 sfree(pf);
6060 freetree234(ssh->rportfwds);
6061 }
6062 sfree(ssh->deferred_send_data);
6063 if (ssh->x11auth)
6064 x11_free_auth(ssh->x11auth);
6065 sfree(ssh->do_ssh_init_state);
6066 sfree(ssh->do_ssh1_login_state);
6067 sfree(ssh->do_ssh2_transport_state);
6068 sfree(ssh->do_ssh2_authconn_state);
6069
6070 if (ssh->s)
6071 sk_close(ssh->s);
6072 sfree(ssh);
6073 }
6074
6075 /*
6076 * Reconfigure the SSH backend.
6077 *
6078 * Currently, this function does nothing very useful. In future,
6079 * however, we could do some handy things with it. For example, we
6080 * could make the port forwarding configurer active in the Change
6081 * Settings box, and this routine could close down existing
6082 * forwardings and open up new ones in response to changes.
6083 */
6084 static void ssh_reconfig(void *handle, Config *cfg)
6085 {
6086 Ssh ssh = (Ssh) handle;
6087 ssh->cfg = *cfg; /* STRUCTURE COPY */
6088 }
6089
6090 /*
6091 * Called to send data down the Telnet connection.
6092 */
6093 static int ssh_send(void *handle, char *buf, int len)
6094 {
6095 Ssh ssh = (Ssh) handle;
6096
6097 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
6098 return 0;
6099
6100 ssh->protocol(ssh, (unsigned char *)buf, len, 0);
6101
6102 return ssh_sendbuffer(ssh);
6103 }
6104
6105 /*
6106 * Called to query the current amount of buffered stdin data.
6107 */
6108 static int ssh_sendbuffer(void *handle)
6109 {
6110 Ssh ssh = (Ssh) handle;
6111 int override_value;
6112
6113 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
6114 return 0;
6115
6116 /*
6117 * If the SSH socket itself has backed up, add the total backup
6118 * size on that to any individual buffer on the stdin channel.
6119 */
6120 override_value = 0;
6121 if (ssh->throttled_all)
6122 override_value = ssh->overall_bufsize;
6123
6124 if (ssh->version == 1) {
6125 return override_value;
6126 } else if (ssh->version == 2) {
6127 if (!ssh->mainchan || ssh->mainchan->closes > 0)
6128 return override_value;
6129 else
6130 return (override_value +
6131 bufchain_size(&ssh->mainchan->v.v2.outbuffer));
6132 }
6133
6134 return 0;
6135 }
6136
6137 /*
6138 * Called to set the size of the window from SSH's POV.
6139 */
6140 static void ssh_size(void *handle, int width, int height)
6141 {
6142 Ssh ssh = (Ssh) handle;
6143
6144 ssh->term_width = width;
6145 ssh->term_height = height;
6146
6147 switch (ssh->state) {
6148 case SSH_STATE_BEFORE_SIZE:
6149 case SSH_STATE_PREPACKET:
6150 case SSH_STATE_CLOSED:
6151 break; /* do nothing */
6152 case SSH_STATE_INTERMED:
6153 ssh->size_needed = TRUE; /* buffer for later */
6154 break;
6155 case SSH_STATE_SESSION:
6156 if (!ssh->cfg.nopty) {
6157 if (ssh->version == 1) {
6158 send_packet(ssh, SSH1_CMSG_WINDOW_SIZE,
6159 PKT_INT, ssh->term_height,
6160 PKT_INT, ssh->term_width,
6161 PKT_INT, 0, PKT_INT, 0, PKT_END);
6162 } else {
6163 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
6164 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
6165 ssh2_pkt_addstring(ssh, "window-change");
6166 ssh2_pkt_addbool(ssh, 0);
6167 ssh2_pkt_adduint32(ssh, ssh->term_width);
6168 ssh2_pkt_adduint32(ssh, ssh->term_height);
6169 ssh2_pkt_adduint32(ssh, 0);
6170 ssh2_pkt_adduint32(ssh, 0);
6171 ssh2_pkt_send(ssh);
6172 }
6173 }
6174 break;
6175 }
6176 }
6177
6178 /*
6179 * Send Telnet special codes. TS_EOF is useful for `plink', so you
6180 * can send an EOF and collect resulting output (e.g. `plink
6181 * hostname sort').
6182 */
6183 static void ssh_special(void *handle, Telnet_Special code)
6184 {
6185 Ssh ssh = (Ssh) handle;
6186
6187 if (code == TS_EOF) {
6188 if (ssh->state != SSH_STATE_SESSION) {
6189 /*
6190 * Buffer the EOF in case we are pre-SESSION, so we can
6191 * send it as soon as we reach SESSION.
6192 */
6193 if (code == TS_EOF)
6194 ssh->eof_needed = TRUE;
6195 return;
6196 }
6197 if (ssh->version == 1) {
6198 send_packet(ssh, SSH1_CMSG_EOF, PKT_END);
6199 } else {
6200 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_EOF);
6201 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
6202 ssh2_pkt_send(ssh);
6203 }
6204 logevent("Sent EOF message");
6205 } else if (code == TS_PING) {
6206 if (ssh->state == SSH_STATE_CLOSED
6207 || ssh->state == SSH_STATE_PREPACKET) return;
6208 if (ssh->version == 1) {
6209 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE))
6210 send_packet(ssh, SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
6211 } else {
6212 ssh2_pkt_init(ssh, SSH2_MSG_IGNORE);
6213 ssh2_pkt_addstring_start(ssh);
6214 ssh2_pkt_send(ssh);
6215 }
6216 } else {
6217 /* do nothing */
6218 }
6219 }
6220
6221 void *new_sock_channel(void *handle, Socket s)
6222 {
6223 Ssh ssh = (Ssh) handle;
6224 struct ssh_channel *c;
6225 c = smalloc(sizeof(struct ssh_channel));
6226 c->ssh = ssh;
6227
6228 if (c) {
6229 c->remoteid = -1; /* to be set when open confirmed */
6230 c->localid = alloc_channel_id(ssh);
6231 c->closes = 0;
6232 c->type = CHAN_SOCKDATA_DORMANT;/* identify channel type */
6233 c->u.pfd.s = s;
6234 bufchain_init(&c->v.v2.outbuffer);
6235 add234(ssh->channels, c);
6236 }
6237 return c;
6238 }
6239
6240 /*
6241 * This is called when stdout/stderr (the entity to which
6242 * from_backend sends data) manages to clear some backlog.
6243 */
6244 static void ssh_unthrottle(void *handle, int bufsize)
6245 {
6246 Ssh ssh = (Ssh) handle;
6247 if (ssh->version == 1) {
6248 if (ssh->v1_stdout_throttling && bufsize < SSH1_BUFFER_LIMIT) {
6249 ssh->v1_stdout_throttling = 0;
6250 ssh1_throttle(ssh, -1);
6251 }
6252 } else {
6253 if (ssh->mainchan && ssh->mainchan->closes == 0)
6254 ssh2_set_window(ssh->mainchan, OUR_V2_WINSIZE - bufsize);
6255 }
6256 }
6257
6258 void ssh_send_port_open(void *channel, char *hostname, int port, char *org)
6259 {
6260 struct ssh_channel *c = (struct ssh_channel *)channel;
6261 Ssh ssh = c->ssh;
6262
6263 logeventf(ssh, "Opening forwarded connection to %s:%d", hostname, port);
6264
6265 if (ssh->version == 1) {
6266 send_packet(ssh, SSH1_MSG_PORT_OPEN,
6267 PKT_INT, c->localid,
6268 PKT_STR, hostname,
6269 PKT_INT, port,
6270 //PKT_STR, <org:orgport>,
6271 PKT_END);
6272 } else {
6273 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN);
6274 ssh2_pkt_addstring(ssh, "direct-tcpip");
6275 ssh2_pkt_adduint32(ssh, c->localid);
6276 c->v.v2.locwindow = OUR_V2_WINSIZE;
6277 ssh2_pkt_adduint32(ssh, c->v.v2.locwindow);/* our window size */
6278 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
6279 ssh2_pkt_addstring(ssh, hostname);
6280 ssh2_pkt_adduint32(ssh, port);
6281 /*
6282 * We make up values for the originator data; partly it's
6283 * too much hassle to keep track, and partly I'm not
6284 * convinced the server should be told details like that
6285 * about my local network configuration.
6286 */
6287 ssh2_pkt_addstring(ssh, "client-side-connection");
6288 ssh2_pkt_adduint32(ssh, 0);
6289 ssh2_pkt_send(ssh);
6290 }
6291 }
6292
6293
6294 static Socket ssh_socket(void *handle)
6295 {
6296 Ssh ssh = (Ssh) handle;
6297 return ssh->s;
6298 }
6299
6300 static int ssh_sendok(void *handle)
6301 {
6302 Ssh ssh = (Ssh) handle;
6303 return ssh->send_ok;
6304 }
6305
6306 static int ssh_ldisc(void *handle, int option)
6307 {
6308 Ssh ssh = (Ssh) handle;
6309 if (option == LD_ECHO)
6310 return ssh->echoing;
6311 if (option == LD_EDIT)
6312 return ssh->editing;
6313 return FALSE;
6314 }
6315
6316 static void ssh_provide_ldisc(void *handle, void *ldisc)
6317 {
6318 Ssh ssh = (Ssh) handle;
6319 ssh->ldisc = ldisc;
6320 }
6321
6322 static void ssh_provide_logctx(void *handle, void *logctx)
6323 {
6324 Ssh ssh = (Ssh) handle;
6325 ssh->logctx = logctx;
6326 }
6327
6328 static int ssh_return_exitcode(void *handle)
6329 {
6330 Ssh ssh = (Ssh) handle;
6331 return ssh->exitcode;
6332 }
6333
6334 /*
6335 * Gross hack: pscp will try to start SFTP but fall back to scp1 if
6336 * that fails. This variable is the means by which scp.c can reach
6337 * into the SSH code and find out which one it got.
6338 */
6339 extern int ssh_fallback_cmd(void *handle)
6340 {
6341 Ssh ssh = (Ssh) handle;
6342 return ssh->fallback_cmd;
6343 }
6344
6345 Backend ssh_backend = {
6346 ssh_init,
6347 ssh_free,
6348 ssh_reconfig,
6349 ssh_send,
6350 ssh_sendbuffer,
6351 ssh_size,
6352 ssh_special,
6353 ssh_socket,
6354 ssh_return_exitcode,
6355 ssh_sendok,
6356 ssh_ldisc,
6357 ssh_provide_ldisc,
6358 ssh_provide_logctx,
6359 ssh_unthrottle,
6360 22
6361 };
Local modifications for Simon Tatham's `PuTTY' SSH client and terminal emulator