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[u/mdw/putty] / ssh.c
1 #include <windows.h>
2 #include <stdio.h>
3 #include <stdlib.h>
4 #include <stdarg.h>
5 #include <assert.h>
6
7 #include "putty.h"
8 #include "tree234.h"
9 #include "ssh.h"
10
11 #ifndef FALSE
12 #define FALSE 0
13 #endif
14 #ifndef TRUE
15 #define TRUE 1
16 #endif
17
18 #define logevent(s) { logevent(s); \
19 if ((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)) \
20 { fprintf(stderr, "%s\n", s); fflush(stderr); } }
21
22 /* logevent, only printf-formatted. */
23 void logeventf(char *fmt, ...)
24 {
25 va_list ap;
26 char stuff[200];
27
28 va_start(ap, fmt);
29 vsprintf(stuff, fmt, ap);
30 va_end(ap);
31 logevent(stuff);
32 }
33
34 #define bombout(msg) ( ssh->state = SSH_STATE_CLOSED, \
35 (ssh->s ? sk_close(ssh->s), ssh->s = NULL : 0), \
36 logeventf msg, connection_fatal msg )
37
38 #define SSH1_MSG_DISCONNECT 1 /* 0x1 */
39 #define SSH1_SMSG_PUBLIC_KEY 2 /* 0x2 */
40 #define SSH1_CMSG_SESSION_KEY 3 /* 0x3 */
41 #define SSH1_CMSG_USER 4 /* 0x4 */
42 #define SSH1_CMSG_AUTH_RSA 6 /* 0x6 */
43 #define SSH1_SMSG_AUTH_RSA_CHALLENGE 7 /* 0x7 */
44 #define SSH1_CMSG_AUTH_RSA_RESPONSE 8 /* 0x8 */
45 #define SSH1_CMSG_AUTH_PASSWORD 9 /* 0x9 */
46 #define SSH1_CMSG_REQUEST_PTY 10 /* 0xa */
47 #define SSH1_CMSG_WINDOW_SIZE 11 /* 0xb */
48 #define SSH1_CMSG_EXEC_SHELL 12 /* 0xc */
49 #define SSH1_CMSG_EXEC_CMD 13 /* 0xd */
50 #define SSH1_SMSG_SUCCESS 14 /* 0xe */
51 #define SSH1_SMSG_FAILURE 15 /* 0xf */
52 #define SSH1_CMSG_STDIN_DATA 16 /* 0x10 */
53 #define SSH1_SMSG_STDOUT_DATA 17 /* 0x11 */
54 #define SSH1_SMSG_STDERR_DATA 18 /* 0x12 */
55 #define SSH1_CMSG_EOF 19 /* 0x13 */
56 #define SSH1_SMSG_EXIT_STATUS 20 /* 0x14 */
57 #define SSH1_MSG_CHANNEL_OPEN_CONFIRMATION 21 /* 0x15 */
58 #define SSH1_MSG_CHANNEL_OPEN_FAILURE 22 /* 0x16 */
59 #define SSH1_MSG_CHANNEL_DATA 23 /* 0x17 */
60 #define SSH1_MSG_CHANNEL_CLOSE 24 /* 0x18 */
61 #define SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION 25 /* 0x19 */
62 #define SSH1_SMSG_X11_OPEN 27 /* 0x1b */
63 #define SSH1_CMSG_PORT_FORWARD_REQUEST 28 /* 0x1c */
64 #define SSH1_MSG_PORT_OPEN 29 /* 0x1d */
65 #define SSH1_CMSG_AGENT_REQUEST_FORWARDING 30 /* 0x1e */
66 #define SSH1_SMSG_AGENT_OPEN 31 /* 0x1f */
67 #define SSH1_MSG_IGNORE 32 /* 0x20 */
68 #define SSH1_CMSG_EXIT_CONFIRMATION 33 /* 0x21 */
69 #define SSH1_CMSG_X11_REQUEST_FORWARDING 34 /* 0x22 */
70 #define SSH1_CMSG_AUTH_RHOSTS_RSA 35 /* 0x23 */
71 #define SSH1_MSG_DEBUG 36 /* 0x24 */
72 #define SSH1_CMSG_REQUEST_COMPRESSION 37 /* 0x25 */
73 #define SSH1_CMSG_AUTH_TIS 39 /* 0x27 */
74 #define SSH1_SMSG_AUTH_TIS_CHALLENGE 40 /* 0x28 */
75 #define SSH1_CMSG_AUTH_TIS_RESPONSE 41 /* 0x29 */
76 #define SSH1_CMSG_AUTH_CCARD 70 /* 0x46 */
77 #define SSH1_SMSG_AUTH_CCARD_CHALLENGE 71 /* 0x47 */
78 #define SSH1_CMSG_AUTH_CCARD_RESPONSE 72 /* 0x48 */
79
80 #define SSH1_AUTH_TIS 5 /* 0x5 */
81 #define SSH1_AUTH_CCARD 16 /* 0x10 */
82
83 #define SSH1_PROTOFLAG_SCREEN_NUMBER 1 /* 0x1 */
84 /* Mask for protoflags we will echo back to server if seen */
85 #define SSH1_PROTOFLAGS_SUPPORTED 0 /* 0x1 */
86
87 #define SSH2_MSG_DISCONNECT 1 /* 0x1 */
88 #define SSH2_MSG_IGNORE 2 /* 0x2 */
89 #define SSH2_MSG_UNIMPLEMENTED 3 /* 0x3 */
90 #define SSH2_MSG_DEBUG 4 /* 0x4 */
91 #define SSH2_MSG_SERVICE_REQUEST 5 /* 0x5 */
92 #define SSH2_MSG_SERVICE_ACCEPT 6 /* 0x6 */
93 #define SSH2_MSG_KEXINIT 20 /* 0x14 */
94 #define SSH2_MSG_NEWKEYS 21 /* 0x15 */
95 #define SSH2_MSG_KEXDH_INIT 30 /* 0x1e */
96 #define SSH2_MSG_KEXDH_REPLY 31 /* 0x1f */
97 #define SSH2_MSG_KEX_DH_GEX_REQUEST 30 /* 0x1e */
98 #define SSH2_MSG_KEX_DH_GEX_GROUP 31 /* 0x1f */
99 #define SSH2_MSG_KEX_DH_GEX_INIT 32 /* 0x20 */
100 #define SSH2_MSG_KEX_DH_GEX_REPLY 33 /* 0x21 */
101 #define SSH2_MSG_USERAUTH_REQUEST 50 /* 0x32 */
102 #define SSH2_MSG_USERAUTH_FAILURE 51 /* 0x33 */
103 #define SSH2_MSG_USERAUTH_SUCCESS 52 /* 0x34 */
104 #define SSH2_MSG_USERAUTH_BANNER 53 /* 0x35 */
105 #define SSH2_MSG_USERAUTH_PK_OK 60 /* 0x3c */
106 #define SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ 60 /* 0x3c */
107 #define SSH2_MSG_USERAUTH_INFO_REQUEST 60 /* 0x3c */
108 #define SSH2_MSG_USERAUTH_INFO_RESPONSE 61 /* 0x3d */
109 #define SSH2_MSG_GLOBAL_REQUEST 80 /* 0x50 */
110 #define SSH2_MSG_REQUEST_SUCCESS 81 /* 0x51 */
111 #define SSH2_MSG_REQUEST_FAILURE 82 /* 0x52 */
112 #define SSH2_MSG_CHANNEL_OPEN 90 /* 0x5a */
113 #define SSH2_MSG_CHANNEL_OPEN_CONFIRMATION 91 /* 0x5b */
114 #define SSH2_MSG_CHANNEL_OPEN_FAILURE 92 /* 0x5c */
115 #define SSH2_MSG_CHANNEL_WINDOW_ADJUST 93 /* 0x5d */
116 #define SSH2_MSG_CHANNEL_DATA 94 /* 0x5e */
117 #define SSH2_MSG_CHANNEL_EXTENDED_DATA 95 /* 0x5f */
118 #define SSH2_MSG_CHANNEL_EOF 96 /* 0x60 */
119 #define SSH2_MSG_CHANNEL_CLOSE 97 /* 0x61 */
120 #define SSH2_MSG_CHANNEL_REQUEST 98 /* 0x62 */
121 #define SSH2_MSG_CHANNEL_SUCCESS 99 /* 0x63 */
122 #define SSH2_MSG_CHANNEL_FAILURE 100 /* 0x64 */
123
124 /*
125 * Packet type contexts, so that ssh2_pkt_type can correctly decode
126 * the ambiguous type numbers back into the correct type strings.
127 */
128 #define SSH2_PKTCTX_DHGROUP1 0x0001
129 #define SSH2_PKTCTX_DHGEX 0x0002
130 #define SSH2_PKTCTX_PUBLICKEY 0x0010
131 #define SSH2_PKTCTX_PASSWORD 0x0020
132 #define SSH2_PKTCTX_KBDINTER 0x0040
133 #define SSH2_PKTCTX_AUTH_MASK 0x00F0
134
135 #define SSH2_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT 1 /* 0x1 */
136 #define SSH2_DISCONNECT_PROTOCOL_ERROR 2 /* 0x2 */
137 #define SSH2_DISCONNECT_KEY_EXCHANGE_FAILED 3 /* 0x3 */
138 #define SSH2_DISCONNECT_HOST_AUTHENTICATION_FAILED 4 /* 0x4 */
139 #define SSH2_DISCONNECT_MAC_ERROR 5 /* 0x5 */
140 #define SSH2_DISCONNECT_COMPRESSION_ERROR 6 /* 0x6 */
141 #define SSH2_DISCONNECT_SERVICE_NOT_AVAILABLE 7 /* 0x7 */
142 #define SSH2_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED 8 /* 0x8 */
143 #define SSH2_DISCONNECT_HOST_KEY_NOT_VERIFIABLE 9 /* 0x9 */
144 #define SSH2_DISCONNECT_CONNECTION_LOST 10 /* 0xa */
145 #define SSH2_DISCONNECT_BY_APPLICATION 11 /* 0xb */
146 #define SSH2_DISCONNECT_TOO_MANY_CONNECTIONS 12 /* 0xc */
147 #define SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER 13 /* 0xd */
148 #define SSH2_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE 14 /* 0xe */
149 #define SSH2_DISCONNECT_ILLEGAL_USER_NAME 15 /* 0xf */
150
151 static const char *const ssh2_disconnect_reasons[] = {
152 NULL,
153 "SSH_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT",
154 "SSH_DISCONNECT_PROTOCOL_ERROR",
155 "SSH_DISCONNECT_KEY_EXCHANGE_FAILED",
156 "SSH_DISCONNECT_HOST_AUTHENTICATION_FAILED",
157 "SSH_DISCONNECT_MAC_ERROR",
158 "SSH_DISCONNECT_COMPRESSION_ERROR",
159 "SSH_DISCONNECT_SERVICE_NOT_AVAILABLE",
160 "SSH_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED",
161 "SSH_DISCONNECT_HOST_KEY_NOT_VERIFIABLE",
162 "SSH_DISCONNECT_CONNECTION_LOST",
163 "SSH_DISCONNECT_BY_APPLICATION",
164 "SSH_DISCONNECT_TOO_MANY_CONNECTIONS",
165 "SSH_DISCONNECT_AUTH_CANCELLED_BY_USER",
166 "SSH_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE",
167 "SSH_DISCONNECT_ILLEGAL_USER_NAME",
168 };
169
170 #define SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED 1 /* 0x1 */
171 #define SSH2_OPEN_CONNECT_FAILED 2 /* 0x2 */
172 #define SSH2_OPEN_UNKNOWN_CHANNEL_TYPE 3 /* 0x3 */
173 #define SSH2_OPEN_RESOURCE_SHORTAGE 4 /* 0x4 */
174
175 #define SSH2_EXTENDED_DATA_STDERR 1 /* 0x1 */
176
177 /*
178 * Various remote-bug flags.
179 */
180 #define BUG_CHOKES_ON_SSH1_IGNORE 1
181 #define BUG_SSH2_HMAC 2
182 #define BUG_NEEDS_SSH1_PLAIN_PASSWORD 4
183 #define BUG_CHOKES_ON_RSA 8
184 #define BUG_SSH2_RSA_PADDING 16
185 #define BUG_SSH2_DERIVEKEY 32
186 #define BUG_SSH2_DH_GEX 64
187
188 #define translate(x) if (type == x) return #x
189 #define translatec(x,ctx) if (type == x && (pkt_ctx & ctx)) return #x
190 char *ssh1_pkt_type(int type)
191 {
192 translate(SSH1_MSG_DISCONNECT);
193 translate(SSH1_SMSG_PUBLIC_KEY);
194 translate(SSH1_CMSG_SESSION_KEY);
195 translate(SSH1_CMSG_USER);
196 translate(SSH1_CMSG_AUTH_RSA);
197 translate(SSH1_SMSG_AUTH_RSA_CHALLENGE);
198 translate(SSH1_CMSG_AUTH_RSA_RESPONSE);
199 translate(SSH1_CMSG_AUTH_PASSWORD);
200 translate(SSH1_CMSG_REQUEST_PTY);
201 translate(SSH1_CMSG_WINDOW_SIZE);
202 translate(SSH1_CMSG_EXEC_SHELL);
203 translate(SSH1_CMSG_EXEC_CMD);
204 translate(SSH1_SMSG_SUCCESS);
205 translate(SSH1_SMSG_FAILURE);
206 translate(SSH1_CMSG_STDIN_DATA);
207 translate(SSH1_SMSG_STDOUT_DATA);
208 translate(SSH1_SMSG_STDERR_DATA);
209 translate(SSH1_CMSG_EOF);
210 translate(SSH1_SMSG_EXIT_STATUS);
211 translate(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION);
212 translate(SSH1_MSG_CHANNEL_OPEN_FAILURE);
213 translate(SSH1_MSG_CHANNEL_DATA);
214 translate(SSH1_MSG_CHANNEL_CLOSE);
215 translate(SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION);
216 translate(SSH1_SMSG_X11_OPEN);
217 translate(SSH1_CMSG_PORT_FORWARD_REQUEST);
218 translate(SSH1_MSG_PORT_OPEN);
219 translate(SSH1_CMSG_AGENT_REQUEST_FORWARDING);
220 translate(SSH1_SMSG_AGENT_OPEN);
221 translate(SSH1_MSG_IGNORE);
222 translate(SSH1_CMSG_EXIT_CONFIRMATION);
223 translate(SSH1_CMSG_X11_REQUEST_FORWARDING);
224 translate(SSH1_CMSG_AUTH_RHOSTS_RSA);
225 translate(SSH1_MSG_DEBUG);
226 translate(SSH1_CMSG_REQUEST_COMPRESSION);
227 translate(SSH1_CMSG_AUTH_TIS);
228 translate(SSH1_SMSG_AUTH_TIS_CHALLENGE);
229 translate(SSH1_CMSG_AUTH_TIS_RESPONSE);
230 translate(SSH1_CMSG_AUTH_CCARD);
231 translate(SSH1_SMSG_AUTH_CCARD_CHALLENGE);
232 translate(SSH1_CMSG_AUTH_CCARD_RESPONSE);
233 return "unknown";
234 }
235 char *ssh2_pkt_type(int pkt_ctx, int type)
236 {
237 translate(SSH2_MSG_DISCONNECT);
238 translate(SSH2_MSG_IGNORE);
239 translate(SSH2_MSG_UNIMPLEMENTED);
240 translate(SSH2_MSG_DEBUG);
241 translate(SSH2_MSG_SERVICE_REQUEST);
242 translate(SSH2_MSG_SERVICE_ACCEPT);
243 translate(SSH2_MSG_KEXINIT);
244 translate(SSH2_MSG_NEWKEYS);
245 translatec(SSH2_MSG_KEXDH_INIT, SSH2_PKTCTX_DHGROUP1);
246 translatec(SSH2_MSG_KEXDH_REPLY, SSH2_PKTCTX_DHGROUP1);
247 translatec(SSH2_MSG_KEX_DH_GEX_REQUEST, SSH2_PKTCTX_DHGEX);
248 translatec(SSH2_MSG_KEX_DH_GEX_GROUP, SSH2_PKTCTX_DHGEX);
249 translatec(SSH2_MSG_KEX_DH_GEX_INIT, SSH2_PKTCTX_DHGEX);
250 translatec(SSH2_MSG_KEX_DH_GEX_REPLY, SSH2_PKTCTX_DHGEX);
251 translate(SSH2_MSG_USERAUTH_REQUEST);
252 translate(SSH2_MSG_USERAUTH_FAILURE);
253 translate(SSH2_MSG_USERAUTH_SUCCESS);
254 translate(SSH2_MSG_USERAUTH_BANNER);
255 translatec(SSH2_MSG_USERAUTH_PK_OK, SSH2_PKTCTX_PUBLICKEY);
256 translatec(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, SSH2_PKTCTX_PASSWORD);
257 translatec(SSH2_MSG_USERAUTH_INFO_REQUEST, SSH2_PKTCTX_KBDINTER);
258 translatec(SSH2_MSG_USERAUTH_INFO_RESPONSE, SSH2_PKTCTX_KBDINTER);
259 translate(SSH2_MSG_GLOBAL_REQUEST);
260 translate(SSH2_MSG_REQUEST_SUCCESS);
261 translate(SSH2_MSG_REQUEST_FAILURE);
262 translate(SSH2_MSG_CHANNEL_OPEN);
263 translate(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
264 translate(SSH2_MSG_CHANNEL_OPEN_FAILURE);
265 translate(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
266 translate(SSH2_MSG_CHANNEL_DATA);
267 translate(SSH2_MSG_CHANNEL_EXTENDED_DATA);
268 translate(SSH2_MSG_CHANNEL_EOF);
269 translate(SSH2_MSG_CHANNEL_CLOSE);
270 translate(SSH2_MSG_CHANNEL_REQUEST);
271 translate(SSH2_MSG_CHANNEL_SUCCESS);
272 translate(SSH2_MSG_CHANNEL_FAILURE);
273 return "unknown";
274 }
275 #undef translate
276 #undef translatec
277
278 #define GET_32BIT(cp) \
279 (((unsigned long)(unsigned char)(cp)[0] << 24) | \
280 ((unsigned long)(unsigned char)(cp)[1] << 16) | \
281 ((unsigned long)(unsigned char)(cp)[2] << 8) | \
282 ((unsigned long)(unsigned char)(cp)[3]))
283
284 #define PUT_32BIT(cp, value) { \
285 (cp)[0] = (unsigned char)((value) >> 24); \
286 (cp)[1] = (unsigned char)((value) >> 16); \
287 (cp)[2] = (unsigned char)((value) >> 8); \
288 (cp)[3] = (unsigned char)(value); }
289
290 enum { PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR, PKT_BIGNUM };
291
292 /* Coroutine mechanics for the sillier bits of the code */
293 #define crBegin(v) { int *crLine = &v; switch(v) { case 0:;
294 #define crState(t) \
295 struct t *s; \
296 if (!ssh->t) ssh->t = smalloc(sizeof(struct t)); \
297 s = ssh->t;
298 #define crFinish(z) } *crLine = 0; return (z); }
299 #define crFinishV } *crLine = 0; return; }
300 #define crReturn(z) \
301 do {\
302 *crLine =__LINE__; return (z); case __LINE__:;\
303 } while (0)
304 #define crReturnV \
305 do {\
306 *crLine=__LINE__; return; case __LINE__:;\
307 } while (0)
308 #define crStop(z) do{ *crLine = 0; return (z); }while(0)
309 #define crStopV do{ *crLine = 0; return; }while(0)
310 #define crWaitUntil(c) do { crReturn(0); } while (!(c))
311 #define crWaitUntilV(c) do { crReturnV; } while (!(c))
312
313 typedef struct ssh_tag *Ssh;
314
315 extern char *x11_init(Socket *, char *, void *, void *);
316 extern void x11_close(Socket);
317 extern int x11_send(Socket, char *, int);
318 extern void *x11_invent_auth(char *, int, char *, int);
319 extern void x11_unthrottle(Socket s);
320 extern void x11_override_throttle(Socket s, int enable);
321
322 extern char *pfd_newconnect(Socket * s, char *hostname, int port, void *c);
323 extern char *pfd_addforward(char *desthost, int destport, int port,
324 void *backhandle);
325 extern void pfd_close(Socket s);
326 extern int pfd_send(Socket s, char *data, int len);
327 extern void pfd_confirm(Socket s);
328 extern void pfd_unthrottle(Socket s);
329 extern void pfd_override_throttle(Socket s, int enable);
330
331 static void ssh2_pkt_init(Ssh, int pkt_type);
332 static void ssh2_pkt_addbool(Ssh, unsigned char value);
333 static void ssh2_pkt_adduint32(Ssh, unsigned long value);
334 static void ssh2_pkt_addstring_start(Ssh);
335 static void ssh2_pkt_addstring_str(Ssh, char *data);
336 static void ssh2_pkt_addstring_data(Ssh, char *data, int len);
337 static void ssh2_pkt_addstring(Ssh, char *data);
338 static char *ssh2_mpint_fmt(Bignum b, int *len);
339 static void ssh2_pkt_addmp(Ssh, Bignum b);
340 static int ssh2_pkt_construct(Ssh);
341 static void ssh2_pkt_send(Ssh);
342
343 /*
344 * Buffer management constants. There are several of these for
345 * various different purposes:
346 *
347 * - SSH1_BUFFER_LIMIT is the amount of backlog that must build up
348 * on a local data stream before we throttle the whole SSH
349 * connection (in SSH1 only). Throttling the whole connection is
350 * pretty drastic so we set this high in the hope it won't
351 * happen very often.
352 *
353 * - SSH_MAX_BACKLOG is the amount of backlog that must build up
354 * on the SSH connection itself before we defensively throttle
355 * _all_ local data streams. This is pretty drastic too (though
356 * thankfully unlikely in SSH2 since the window mechanism should
357 * ensure that the server never has any need to throttle its end
358 * of the connection), so we set this high as well.
359 *
360 * - OUR_V2_WINSIZE is the maximum window size we present on SSH2
361 * channels.
362 */
363
364 #define SSH1_BUFFER_LIMIT 32768
365 #define SSH_MAX_BACKLOG 32768
366 #define OUR_V2_WINSIZE 16384
367
368 const static struct ssh_kex *kex_algs[] = {
369 &ssh_diffiehellman_gex,
370 &ssh_diffiehellman
371 };
372
373 const static struct ssh_signkey *hostkey_algs[] = { &ssh_rsa, &ssh_dss };
374
375 static void *nullmac_make_context(void)
376 {
377 return NULL;
378 }
379 static void nullmac_free_context(void *handle)
380 {
381 }
382 static void nullmac_key(void *handle, unsigned char *key)
383 {
384 }
385 static void nullmac_generate(void *handle, unsigned char *blk, int len,
386 unsigned long seq)
387 {
388 }
389 static int nullmac_verify(void *handle, unsigned char *blk, int len,
390 unsigned long seq)
391 {
392 return 1;
393 }
394 const static struct ssh_mac ssh_mac_none = {
395 nullmac_make_context, nullmac_free_context, nullmac_key,
396 nullmac_generate, nullmac_verify, "none", 0
397 };
398 const static struct ssh_mac *macs[] = {
399 &ssh_sha1, &ssh_md5, &ssh_mac_none
400 };
401 const static struct ssh_mac *buggymacs[] = {
402 &ssh_sha1_buggy, &ssh_md5, &ssh_mac_none
403 };
404
405 static void *ssh_comp_none_init(void)
406 {
407 return NULL;
408 }
409 static void ssh_comp_none_cleanup(void *handle)
410 {
411 }
412 static int ssh_comp_none_block(void *handle, unsigned char *block, int len,
413 unsigned char **outblock, int *outlen)
414 {
415 return 0;
416 }
417 static int ssh_comp_none_disable(void *handle)
418 {
419 return 0;
420 }
421 const static struct ssh_compress ssh_comp_none = {
422 "none",
423 ssh_comp_none_init, ssh_comp_none_cleanup, ssh_comp_none_block,
424 ssh_comp_none_init, ssh_comp_none_cleanup, ssh_comp_none_block,
425 ssh_comp_none_disable, NULL
426 };
427 extern const struct ssh_compress ssh_zlib;
428 const static struct ssh_compress *compressions[] = {
429 &ssh_zlib, &ssh_comp_none
430 };
431
432 enum { /* channel types */
433 CHAN_MAINSESSION,
434 CHAN_X11,
435 CHAN_AGENT,
436 CHAN_SOCKDATA,
437 CHAN_SOCKDATA_DORMANT /* one the remote hasn't confirmed */
438 };
439
440 /*
441 * 2-3-4 tree storing channels.
442 */
443 struct ssh_channel {
444 Ssh ssh; /* pointer back to main context */
445 unsigned remoteid, localid;
446 int type;
447 /*
448 * In SSH1, this value contains four bits:
449 *
450 * 1 We have sent SSH1_MSG_CHANNEL_CLOSE.
451 * 2 We have sent SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION.
452 * 4 We have received SSH1_MSG_CHANNEL_CLOSE.
453 * 8 We have received SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION.
454 *
455 * A channel is completely finished with when all four bits are set.
456 */
457 int closes;
458 union {
459 struct ssh1_data_channel {
460 int throttling;
461 } v1;
462 struct ssh2_data_channel {
463 bufchain outbuffer;
464 unsigned remwindow, remmaxpkt;
465 unsigned locwindow;
466 } v2;
467 } v;
468 union {
469 struct ssh_agent_channel {
470 unsigned char *message;
471 unsigned char msglen[4];
472 int lensofar, totallen;
473 } a;
474 struct ssh_x11_channel {
475 Socket s;
476 } x11;
477 struct ssh_pfd_channel {
478 Socket s;
479 } pfd;
480 } u;
481 };
482
483 /*
484 * 2-3-4 tree storing remote->local port forwardings. SSH 1 and SSH
485 * 2 use this structure in different ways, reflecting SSH 2's
486 * altogether saner approach to port forwarding.
487 *
488 * In SSH 1, you arrange a remote forwarding by sending the server
489 * the remote port number, and the local destination host:port.
490 * When a connection comes in, the server sends you back that
491 * host:port pair, and you connect to it. This is a ready-made
492 * security hole if you're not on the ball: a malicious server
493 * could send you back _any_ host:port pair, so if you trustingly
494 * connect to the address it gives you then you've just opened the
495 * entire inside of your corporate network just by connecting
496 * through it to a dodgy SSH server. Hence, we must store a list of
497 * host:port pairs we _are_ trying to forward to, and reject a
498 * connection request from the server if it's not in the list.
499 *
500 * In SSH 2, each side of the connection minds its own business and
501 * doesn't send unnecessary information to the other. You arrange a
502 * remote forwarding by sending the server just the remote port
503 * number. When a connection comes in, the server tells you which
504 * of its ports was connected to; and _you_ have to remember what
505 * local host:port pair went with that port number.
506 *
507 * Hence: in SSH 1 this structure stores host:port pairs we intend
508 * to allow connections to, and is indexed by those host:port
509 * pairs. In SSH 2 it stores a mapping from source port to
510 * destination host:port pair, and is indexed by source port.
511 */
512 struct ssh_rportfwd {
513 unsigned sport, dport;
514 char dhost[256];
515 };
516
517 struct Packet {
518 long length;
519 int type;
520 unsigned char *data;
521 unsigned char *body;
522 long savedpos;
523 long maxlen;
524 };
525
526 static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt);
527 static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt);
528 static void ssh_size(void *handle, int width, int height);
529 static void ssh_special(void *handle, Telnet_Special);
530 static int ssh2_try_send(struct ssh_channel *c);
531 static void ssh2_add_channel_data(struct ssh_channel *c, char *buf, int len);
532 static void ssh_throttle_all(Ssh ssh, int enable, int bufsize);
533 static void ssh2_set_window(struct ssh_channel *c, unsigned newwin);
534 static int ssh_sendbuffer(void *handle);
535
536 struct rdpkt1_state_tag {
537 long len, pad, biglen, to_read;
538 unsigned long realcrc, gotcrc;
539 unsigned char *p;
540 int i;
541 int chunk;
542 };
543
544 struct rdpkt2_state_tag {
545 long len, pad, payload, packetlen, maclen;
546 int i;
547 int cipherblk;
548 unsigned long incoming_sequence;
549 };
550
551 struct ssh_tag {
552 const struct plug_function_table *fn;
553 /* the above field _must_ be first in the structure */
554
555 SHA_State exhash, exhashbase;
556
557 Socket s;
558
559 void *ldisc;
560
561 unsigned char session_key[32];
562 int v1_compressing;
563 int v1_remote_protoflags;
564 int v1_local_protoflags;
565 int agentfwd_enabled;
566 int X11_fwd_enabled;
567 int remote_bugs;
568 const struct ssh_cipher *cipher;
569 void *v1_cipher_ctx;
570 void *crcda_ctx;
571 const struct ssh2_cipher *cscipher, *sccipher;
572 void *cs_cipher_ctx, *sc_cipher_ctx;
573 const struct ssh_mac *csmac, *scmac;
574 void *cs_mac_ctx, *sc_mac_ctx;
575 const struct ssh_compress *cscomp, *sccomp;
576 void *cs_comp_ctx, *sc_comp_ctx;
577 const struct ssh_kex *kex;
578 const struct ssh_signkey *hostkey;
579 unsigned char v2_session_id[20];
580 void *kex_ctx;
581
582 char *savedhost;
583 int savedport;
584 int send_ok;
585 int echoing, editing;
586
587 void *frontend;
588
589 int term_width, term_height;
590
591 tree234 *channels; /* indexed by local id */
592 struct ssh_channel *mainchan; /* primary session channel */
593 int exitcode;
594
595 tree234 *rportfwds;
596
597 enum {
598 SSH_STATE_PREPACKET,
599 SSH_STATE_BEFORE_SIZE,
600 SSH_STATE_INTERMED,
601 SSH_STATE_SESSION,
602 SSH_STATE_CLOSED
603 } state;
604
605 int size_needed, eof_needed;
606
607 struct Packet pktin;
608 struct Packet pktout;
609 unsigned char *deferred_send_data;
610 int deferred_len, deferred_size;
611
612 /*
613 * Gross hack: pscp will try to start SFTP but fall back to
614 * scp1 if that fails. This variable is the means by which
615 * scp.c can reach into the SSH code and find out which one it
616 * got.
617 */
618 int fallback_cmd;
619
620 /*
621 * Used for username and password input.
622 */
623 char *userpass_input_buffer;
624 int userpass_input_buflen;
625 int userpass_input_bufpos;
626 int userpass_input_echo;
627
628 char *portfwd_strptr;
629 int pkt_ctx;
630
631 void *x11auth;
632
633 int version;
634 int v1_throttle_count;
635 int overall_bufsize;
636 int throttled_all;
637 int v1_stdout_throttling;
638 int v2_outgoing_sequence;
639
640 int ssh1_rdpkt_crstate;
641 int ssh2_rdpkt_crstate;
642 int do_ssh_init_crstate;
643 int ssh_gotdata_crstate;
644 int ssh1_protocol_crstate;
645 int do_ssh1_login_crstate;
646 int do_ssh2_transport_crstate;
647 int do_ssh2_authconn_crstate;
648
649 void *do_ssh_init_state;
650 void *do_ssh1_login_state;
651 void *do_ssh2_transport_state;
652 void *do_ssh2_authconn_state;
653
654 struct rdpkt1_state_tag rdpkt1_state;
655 struct rdpkt2_state_tag rdpkt2_state;
656
657 void (*protocol) (Ssh ssh, unsigned char *in, int inlen, int ispkt);
658 int (*s_rdpkt) (Ssh ssh, unsigned char **data, int *datalen);
659 };
660
661 static int ssh_channelcmp(void *av, void *bv)
662 {
663 struct ssh_channel *a = (struct ssh_channel *) av;
664 struct ssh_channel *b = (struct ssh_channel *) bv;
665 if (a->localid < b->localid)
666 return -1;
667 if (a->localid > b->localid)
668 return +1;
669 return 0;
670 }
671 static int ssh_channelfind(void *av, void *bv)
672 {
673 unsigned *a = (unsigned *) av;
674 struct ssh_channel *b = (struct ssh_channel *) bv;
675 if (*a < b->localid)
676 return -1;
677 if (*a > b->localid)
678 return +1;
679 return 0;
680 }
681
682 static int ssh_rportcmp_ssh1(void *av, void *bv)
683 {
684 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
685 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
686 int i;
687 if ( (i = strcmp(a->dhost, b->dhost)) != 0)
688 return i < 0 ? -1 : +1;
689 if (a->dport > b->dport)
690 return +1;
691 if (a->dport < b->dport)
692 return -1;
693 return 0;
694 }
695
696 static int ssh_rportcmp_ssh2(void *av, void *bv)
697 {
698 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
699 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
700
701 if (a->sport > b->sport)
702 return +1;
703 if (a->sport < b->sport)
704 return -1;
705 return 0;
706 }
707
708 static int alloc_channel_id(Ssh ssh)
709 {
710 const unsigned CHANNEL_NUMBER_OFFSET = 256;
711 unsigned low, high, mid;
712 int tsize;
713 struct ssh_channel *c;
714
715 /*
716 * First-fit allocation of channel numbers: always pick the
717 * lowest unused one. To do this, binary-search using the
718 * counted B-tree to find the largest channel ID which is in a
719 * contiguous sequence from the beginning. (Precisely
720 * everything in that sequence must have ID equal to its tree
721 * index plus CHANNEL_NUMBER_OFFSET.)
722 */
723 tsize = count234(ssh->channels);
724
725 low = -1;
726 high = tsize;
727 while (high - low > 1) {
728 mid = (high + low) / 2;
729 c = index234(ssh->channels, mid);
730 if (c->localid == mid + CHANNEL_NUMBER_OFFSET)
731 low = mid; /* this one is fine */
732 else
733 high = mid; /* this one is past it */
734 }
735 /*
736 * Now low points to either -1, or the tree index of the
737 * largest ID in the initial sequence.
738 */
739 {
740 unsigned i = low + 1 + CHANNEL_NUMBER_OFFSET;
741 assert(NULL == find234(ssh->channels, &i, ssh_channelfind));
742 }
743 return low + 1 + CHANNEL_NUMBER_OFFSET;
744 }
745
746 static void c_write(Ssh ssh, char *buf, int len)
747 {
748 if ((flags & FLAG_STDERR)) {
749 int i;
750 for (i = 0; i < len; i++)
751 if (buf[i] != '\r')
752 fputc(buf[i], stderr);
753 return;
754 }
755 from_backend(ssh->frontend, 1, buf, len);
756 }
757
758 static void c_write_untrusted(Ssh ssh, char *buf, int len)
759 {
760 int i;
761 for (i = 0; i < len; i++) {
762 if (buf[i] == '\n')
763 c_write(ssh, "\r\n", 2);
764 else if ((buf[i] & 0x60) || (buf[i] == '\r'))
765 c_write(ssh, buf + i, 1);
766 }
767 }
768
769 static void c_write_str(Ssh ssh, char *buf)
770 {
771 c_write(ssh, buf, strlen(buf));
772 }
773
774 /*
775 * Collect incoming data in the incoming packet buffer.
776 * Decipher and verify the packet when it is completely read.
777 * Drop SSH1_MSG_DEBUG and SSH1_MSG_IGNORE packets.
778 * Update the *data and *datalen variables.
779 * Return the additional nr of bytes needed, or 0 when
780 * a complete packet is available.
781 */
782 static int ssh1_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
783 {
784 struct rdpkt1_state_tag *st = &ssh->rdpkt1_state;
785
786 crBegin(ssh->ssh1_rdpkt_crstate);
787
788 next_packet:
789
790 ssh->pktin.type = 0;
791 ssh->pktin.length = 0;
792
793 for (st->i = st->len = 0; st->i < 4; st->i++) {
794 while ((*datalen) == 0)
795 crReturn(4 - st->i);
796 st->len = (st->len << 8) + **data;
797 (*data)++, (*datalen)--;
798 }
799
800 st->pad = 8 - (st->len % 8);
801 st->biglen = st->len + st->pad;
802 ssh->pktin.length = st->len - 5;
803
804 if (ssh->pktin.maxlen < st->biglen) {
805 ssh->pktin.maxlen = st->biglen;
806 ssh->pktin.data = srealloc(ssh->pktin.data, st->biglen + APIEXTRA);
807 }
808
809 st->to_read = st->biglen;
810 st->p = ssh->pktin.data;
811 while (st->to_read > 0) {
812 st->chunk = st->to_read;
813 while ((*datalen) == 0)
814 crReturn(st->to_read);
815 if (st->chunk > (*datalen))
816 st->chunk = (*datalen);
817 memcpy(st->p, *data, st->chunk);
818 *data += st->chunk;
819 *datalen -= st->chunk;
820 st->p += st->chunk;
821 st->to_read -= st->chunk;
822 }
823
824 if (ssh->cipher && detect_attack(ssh->crcda_ctx, ssh->pktin.data,
825 st->biglen, NULL)) {
826 bombout(("Network attack (CRC compensation) detected!"));
827 crReturn(0);
828 }
829
830 if (ssh->cipher)
831 ssh->cipher->decrypt(ssh->v1_cipher_ctx, ssh->pktin.data, st->biglen);
832
833 st->realcrc = crc32(ssh->pktin.data, st->biglen - 4);
834 st->gotcrc = GET_32BIT(ssh->pktin.data + st->biglen - 4);
835 if (st->gotcrc != st->realcrc) {
836 bombout(("Incorrect CRC received on packet"));
837 crReturn(0);
838 }
839
840 ssh->pktin.body = ssh->pktin.data + st->pad + 1;
841
842 if (ssh->v1_compressing) {
843 unsigned char *decompblk;
844 int decomplen;
845 zlib_decompress_block(ssh->sc_comp_ctx,
846 ssh->pktin.body - 1, ssh->pktin.length + 1,
847 &decompblk, &decomplen);
848
849 if (ssh->pktin.maxlen < st->pad + decomplen) {
850 ssh->pktin.maxlen = st->pad + decomplen;
851 ssh->pktin.data = srealloc(ssh->pktin.data,
852 ssh->pktin.maxlen + APIEXTRA);
853 ssh->pktin.body = ssh->pktin.data + st->pad + 1;
854 }
855
856 memcpy(ssh->pktin.body - 1, decompblk, decomplen);
857 sfree(decompblk);
858 ssh->pktin.length = decomplen - 1;
859 }
860
861 ssh->pktin.type = ssh->pktin.body[-1];
862
863 log_packet(PKT_INCOMING, ssh->pktin.type, ssh1_pkt_type(ssh->pktin.type),
864 ssh->pktin.body, ssh->pktin.length);
865
866 if (ssh->pktin.type == SSH1_SMSG_STDOUT_DATA ||
867 ssh->pktin.type == SSH1_SMSG_STDERR_DATA ||
868 ssh->pktin.type == SSH1_MSG_DEBUG ||
869 ssh->pktin.type == SSH1_SMSG_AUTH_TIS_CHALLENGE ||
870 ssh->pktin.type == SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
871 long stringlen = GET_32BIT(ssh->pktin.body);
872 if (stringlen + 4 != ssh->pktin.length) {
873 bombout(("Received data packet with bogus string length"));
874 crReturn(0);
875 }
876 }
877
878 if (ssh->pktin.type == SSH1_MSG_DEBUG) {
879 /* log debug message */
880 char buf[512];
881 int stringlen = GET_32BIT(ssh->pktin.body);
882 strcpy(buf, "Remote debug message: ");
883 if (stringlen > 480)
884 stringlen = 480;
885 memcpy(buf + 8, ssh->pktin.body + 4, stringlen);
886 buf[8 + stringlen] = '\0';
887 logevent(buf);
888 goto next_packet;
889 } else if (ssh->pktin.type == SSH1_MSG_IGNORE) {
890 /* do nothing */
891 goto next_packet;
892 }
893
894 if (ssh->pktin.type == SSH1_MSG_DISCONNECT) {
895 /* log reason code in disconnect message */
896 char buf[256];
897 unsigned msglen = GET_32BIT(ssh->pktin.body);
898 unsigned nowlen;
899 strcpy(buf, "Remote sent disconnect: ");
900 nowlen = strlen(buf);
901 if (msglen > sizeof(buf) - nowlen - 1)
902 msglen = sizeof(buf) - nowlen - 1;
903 memcpy(buf + nowlen, ssh->pktin.body + 4, msglen);
904 buf[nowlen + msglen] = '\0';
905 /* logevent(buf); (this is now done within the bombout macro) */
906 bombout(("Server sent disconnect message:\n\"%s\"", buf+nowlen));
907 crReturn(0);
908 }
909
910 crFinish(0);
911 }
912
913 static int ssh2_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
914 {
915 struct rdpkt2_state_tag *st = &ssh->rdpkt2_state;
916
917 crBegin(ssh->ssh2_rdpkt_crstate);
918
919 next_packet:
920 ssh->pktin.type = 0;
921 ssh->pktin.length = 0;
922 if (ssh->sccipher)
923 st->cipherblk = ssh->sccipher->blksize;
924 else
925 st->cipherblk = 8;
926 if (st->cipherblk < 8)
927 st->cipherblk = 8;
928
929 if (ssh->pktin.maxlen < st->cipherblk) {
930 ssh->pktin.maxlen = st->cipherblk;
931 ssh->pktin.data = srealloc(ssh->pktin.data, st->cipherblk + APIEXTRA);
932 }
933
934 /*
935 * Acquire and decrypt the first block of the packet. This will
936 * contain the length and padding details.
937 */
938 for (st->i = st->len = 0; st->i < st->cipherblk; st->i++) {
939 while ((*datalen) == 0)
940 crReturn(st->cipherblk - st->i);
941 ssh->pktin.data[st->i] = *(*data)++;
942 (*datalen)--;
943 }
944
945 if (ssh->sccipher)
946 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
947 ssh->pktin.data, st->cipherblk);
948
949 /*
950 * Now get the length and padding figures.
951 */
952 st->len = GET_32BIT(ssh->pktin.data);
953 st->pad = ssh->pktin.data[4];
954
955 /*
956 * _Completely_ silly lengths should be stomped on before they
957 * do us any more damage.
958 */
959 if (st->len < 0 || st->pad < 0 || st->len + st->pad < 0) {
960 bombout(("Incoming packet was garbled on decryption"));
961 crReturn(0);
962 }
963
964 /*
965 * This enables us to deduce the payload length.
966 */
967 st->payload = st->len - st->pad - 1;
968
969 ssh->pktin.length = st->payload + 5;
970
971 /*
972 * So now we can work out the total packet length.
973 */
974 st->packetlen = st->len + 4;
975 st->maclen = ssh->scmac ? ssh->scmac->len : 0;
976
977 /*
978 * Adjust memory allocation if packet is too big.
979 */
980 if (ssh->pktin.maxlen < st->packetlen + st->maclen) {
981 ssh->pktin.maxlen = st->packetlen + st->maclen;
982 ssh->pktin.data = srealloc(ssh->pktin.data,
983 ssh->pktin.maxlen + APIEXTRA);
984 }
985
986 /*
987 * Read and decrypt the remainder of the packet.
988 */
989 for (st->i = st->cipherblk; st->i < st->packetlen + st->maclen;
990 st->i++) {
991 while ((*datalen) == 0)
992 crReturn(st->packetlen + st->maclen - st->i);
993 ssh->pktin.data[st->i] = *(*data)++;
994 (*datalen)--;
995 }
996 /* Decrypt everything _except_ the MAC. */
997 if (ssh->sccipher)
998 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
999 ssh->pktin.data + st->cipherblk,
1000 st->packetlen - st->cipherblk);
1001
1002 /*
1003 * Check the MAC.
1004 */
1005 if (ssh->scmac
1006 && !ssh->scmac->verify(ssh->sc_mac_ctx, ssh->pktin.data, st->len + 4,
1007 st->incoming_sequence)) {
1008 bombout(("Incorrect MAC received on packet"));
1009 crReturn(0);
1010 }
1011 st->incoming_sequence++; /* whether or not we MACed */
1012
1013 /*
1014 * Decompress packet payload.
1015 */
1016 {
1017 unsigned char *newpayload;
1018 int newlen;
1019 if (ssh->sccomp &&
1020 ssh->sccomp->decompress(ssh->sc_comp_ctx,
1021 ssh->pktin.data + 5, ssh->pktin.length - 5,
1022 &newpayload, &newlen)) {
1023 if (ssh->pktin.maxlen < newlen + 5) {
1024 ssh->pktin.maxlen = newlen + 5;
1025 ssh->pktin.data = srealloc(ssh->pktin.data,
1026 ssh->pktin.maxlen + APIEXTRA);
1027 }
1028 ssh->pktin.length = 5 + newlen;
1029 memcpy(ssh->pktin.data + 5, newpayload, newlen);
1030 sfree(newpayload);
1031 }
1032 }
1033
1034 ssh->pktin.savedpos = 6;
1035 ssh->pktin.type = ssh->pktin.data[5];
1036
1037 log_packet(PKT_INCOMING, ssh->pktin.type,
1038 ssh2_pkt_type(ssh->pkt_ctx, ssh->pktin.type),
1039 ssh->pktin.data+6, ssh->pktin.length-6);
1040
1041 switch (ssh->pktin.type) {
1042 /*
1043 * These packets we must handle instantly.
1044 */
1045 case SSH2_MSG_DISCONNECT:
1046 {
1047 /* log reason code in disconnect message */
1048 char buf[256];
1049 int reason = GET_32BIT(ssh->pktin.data + 6);
1050 unsigned msglen = GET_32BIT(ssh->pktin.data + 10);
1051 unsigned nowlen;
1052 if (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) {
1053 sprintf(buf, "Received disconnect message (%s)",
1054 ssh2_disconnect_reasons[reason]);
1055 } else {
1056 sprintf(buf, "Received disconnect message (unknown type %d)",
1057 reason);
1058 }
1059 logevent(buf);
1060 strcpy(buf, "Disconnection message text: ");
1061 nowlen = strlen(buf);
1062 if (msglen > sizeof(buf) - nowlen - 1)
1063 msglen = sizeof(buf) - nowlen - 1;
1064 memcpy(buf + nowlen, ssh->pktin.data + 14, msglen);
1065 buf[nowlen + msglen] = '\0';
1066 logevent(buf);
1067 bombout(("Server sent disconnect message\ntype %d (%s):\n\"%s\"",
1068 reason,
1069 (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) ?
1070 ssh2_disconnect_reasons[reason] : "unknown",
1071 buf+nowlen));
1072 crReturn(0);
1073 }
1074 break;
1075 case SSH2_MSG_IGNORE:
1076 goto next_packet;
1077 case SSH2_MSG_DEBUG:
1078 {
1079 /* log the debug message */
1080 char buf[512];
1081 /* int display = ssh->pktin.body[6]; */
1082 int stringlen = GET_32BIT(ssh->pktin.data+7);
1083 int prefix;
1084 strcpy(buf, "Remote debug message: ");
1085 prefix = strlen(buf);
1086 if (stringlen > (int)(sizeof(buf)-prefix-1))
1087 stringlen = sizeof(buf)-prefix-1;
1088 memcpy(buf + prefix, ssh->pktin.data + 11, stringlen);
1089 buf[prefix + stringlen] = '\0';
1090 logevent(buf);
1091 }
1092 goto next_packet; /* FIXME: print the debug message */
1093
1094 /*
1095 * These packets we need do nothing about here.
1096 */
1097 case SSH2_MSG_UNIMPLEMENTED:
1098 case SSH2_MSG_SERVICE_REQUEST:
1099 case SSH2_MSG_SERVICE_ACCEPT:
1100 case SSH2_MSG_KEXINIT:
1101 case SSH2_MSG_NEWKEYS:
1102 case SSH2_MSG_KEXDH_INIT:
1103 case SSH2_MSG_KEXDH_REPLY:
1104 /* case SSH2_MSG_KEX_DH_GEX_REQUEST: duplicate case value */
1105 /* case SSH2_MSG_KEX_DH_GEX_GROUP: duplicate case value */
1106 case SSH2_MSG_KEX_DH_GEX_INIT:
1107 case SSH2_MSG_KEX_DH_GEX_REPLY:
1108 case SSH2_MSG_USERAUTH_REQUEST:
1109 case SSH2_MSG_USERAUTH_FAILURE:
1110 case SSH2_MSG_USERAUTH_SUCCESS:
1111 case SSH2_MSG_USERAUTH_BANNER:
1112 case SSH2_MSG_USERAUTH_PK_OK:
1113 /* case SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ: duplicate case value */
1114 /* case SSH2_MSG_USERAUTH_INFO_REQUEST: duplicate case value */
1115 case SSH2_MSG_USERAUTH_INFO_RESPONSE:
1116 case SSH2_MSG_GLOBAL_REQUEST:
1117 case SSH2_MSG_REQUEST_SUCCESS:
1118 case SSH2_MSG_REQUEST_FAILURE:
1119 case SSH2_MSG_CHANNEL_OPEN:
1120 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION:
1121 case SSH2_MSG_CHANNEL_OPEN_FAILURE:
1122 case SSH2_MSG_CHANNEL_WINDOW_ADJUST:
1123 case SSH2_MSG_CHANNEL_DATA:
1124 case SSH2_MSG_CHANNEL_EXTENDED_DATA:
1125 case SSH2_MSG_CHANNEL_EOF:
1126 case SSH2_MSG_CHANNEL_CLOSE:
1127 case SSH2_MSG_CHANNEL_REQUEST:
1128 case SSH2_MSG_CHANNEL_SUCCESS:
1129 case SSH2_MSG_CHANNEL_FAILURE:
1130 break;
1131
1132 /*
1133 * For anything else we send SSH2_MSG_UNIMPLEMENTED.
1134 */
1135 default:
1136 ssh2_pkt_init(ssh, SSH2_MSG_UNIMPLEMENTED);
1137 ssh2_pkt_adduint32(ssh, st->incoming_sequence - 1);
1138 ssh2_pkt_send(ssh);
1139 break;
1140 }
1141
1142 crFinish(0);
1143 }
1144
1145 static void ssh1_pktout_size(Ssh ssh, int len)
1146 {
1147 int pad, biglen;
1148
1149 len += 5; /* type and CRC */
1150 pad = 8 - (len % 8);
1151 biglen = len + pad;
1152
1153 ssh->pktout.length = len - 5;
1154 if (ssh->pktout.maxlen < biglen) {
1155 ssh->pktout.maxlen = biglen;
1156 #ifdef MSCRYPTOAPI
1157 /* Allocate enough buffer space for extra block
1158 * for MS CryptEncrypt() */
1159 ssh->pktout.data = srealloc(ssh->pktout.data, biglen + 12);
1160 #else
1161 ssh->pktout.data = srealloc(ssh->pktout.data, biglen + 4);
1162 #endif
1163 }
1164 ssh->pktout.body = ssh->pktout.data + 4 + pad + 1;
1165 }
1166
1167 static void s_wrpkt_start(Ssh ssh, int type, int len)
1168 {
1169 ssh1_pktout_size(ssh, len);
1170 ssh->pktout.type = type;
1171 }
1172
1173 static int s_wrpkt_prepare(Ssh ssh)
1174 {
1175 int pad, len, biglen, i;
1176 unsigned long crc;
1177
1178 ssh->pktout.body[-1] = ssh->pktout.type;
1179
1180 log_packet(PKT_OUTGOING, ssh->pktout.type, ssh1_pkt_type(ssh->pktout.type),
1181 ssh->pktout.body, ssh->pktout.length);
1182
1183 if (ssh->v1_compressing) {
1184 unsigned char *compblk;
1185 int complen;
1186 zlib_compress_block(ssh->cs_comp_ctx,
1187 ssh->pktout.body - 1, ssh->pktout.length + 1,
1188 &compblk, &complen);
1189 ssh1_pktout_size(ssh, complen - 1);
1190 memcpy(ssh->pktout.body - 1, compblk, complen);
1191 sfree(compblk);
1192 }
1193
1194 len = ssh->pktout.length + 5; /* type and CRC */
1195 pad = 8 - (len % 8);
1196 biglen = len + pad;
1197
1198 for (i = 0; i < pad; i++)
1199 ssh->pktout.data[i + 4] = random_byte();
1200 crc = crc32(ssh->pktout.data + 4, biglen - 4);
1201 PUT_32BIT(ssh->pktout.data + biglen, crc);
1202 PUT_32BIT(ssh->pktout.data, len);
1203
1204 if (ssh->cipher)
1205 ssh->cipher->encrypt(ssh->v1_cipher_ctx, ssh->pktout.data + 4, biglen);
1206
1207 return biglen + 4;
1208 }
1209
1210 static void s_wrpkt(Ssh ssh)
1211 {
1212 int len, backlog;
1213 len = s_wrpkt_prepare(ssh);
1214 backlog = sk_write(ssh->s, ssh->pktout.data, len);
1215 if (backlog > SSH_MAX_BACKLOG)
1216 ssh_throttle_all(ssh, 1, backlog);
1217 }
1218
1219 static void s_wrpkt_defer(Ssh ssh)
1220 {
1221 int len;
1222 len = s_wrpkt_prepare(ssh);
1223 if (ssh->deferred_len + len > ssh->deferred_size) {
1224 ssh->deferred_size = ssh->deferred_len + len + 128;
1225 ssh->deferred_send_data = srealloc(ssh->deferred_send_data,
1226 ssh->deferred_size);
1227 }
1228 memcpy(ssh->deferred_send_data + ssh->deferred_len, ssh->pktout.data, len);
1229 ssh->deferred_len += len;
1230 }
1231
1232 /*
1233 * Construct a packet with the specified contents.
1234 */
1235 static void construct_packet(Ssh ssh, int pkttype, va_list ap1, va_list ap2)
1236 {
1237 unsigned char *p, *argp, argchar;
1238 unsigned long argint;
1239 int pktlen, argtype, arglen;
1240 Bignum bn;
1241
1242 pktlen = 0;
1243 while ((argtype = va_arg(ap1, int)) != PKT_END) {
1244 switch (argtype) {
1245 case PKT_INT:
1246 (void) va_arg(ap1, int);
1247 pktlen += 4;
1248 break;
1249 case PKT_CHAR:
1250 (void) va_arg(ap1, char);
1251 pktlen++;
1252 break;
1253 case PKT_DATA:
1254 (void) va_arg(ap1, unsigned char *);
1255 arglen = va_arg(ap1, int);
1256 pktlen += arglen;
1257 break;
1258 case PKT_STR:
1259 argp = va_arg(ap1, unsigned char *);
1260 arglen = strlen(argp);
1261 pktlen += 4 + arglen;
1262 break;
1263 case PKT_BIGNUM:
1264 bn = va_arg(ap1, Bignum);
1265 pktlen += ssh1_bignum_length(bn);
1266 break;
1267 default:
1268 assert(0);
1269 }
1270 }
1271
1272 s_wrpkt_start(ssh, pkttype, pktlen);
1273 p = ssh->pktout.body;
1274
1275 while ((argtype = va_arg(ap2, int)) != PKT_END) {
1276 switch (argtype) {
1277 case PKT_INT:
1278 argint = va_arg(ap2, int);
1279 PUT_32BIT(p, argint);
1280 p += 4;
1281 break;
1282 case PKT_CHAR:
1283 argchar = va_arg(ap2, unsigned char);
1284 *p = argchar;
1285 p++;
1286 break;
1287 case PKT_DATA:
1288 argp = va_arg(ap2, unsigned char *);
1289 arglen = va_arg(ap2, int);
1290 memcpy(p, argp, arglen);
1291 p += arglen;
1292 break;
1293 case PKT_STR:
1294 argp = va_arg(ap2, unsigned char *);
1295 arglen = strlen(argp);
1296 PUT_32BIT(p, arglen);
1297 memcpy(p + 4, argp, arglen);
1298 p += 4 + arglen;
1299 break;
1300 case PKT_BIGNUM:
1301 bn = va_arg(ap2, Bignum);
1302 p += ssh1_write_bignum(p, bn);
1303 break;
1304 }
1305 }
1306 }
1307
1308 static void send_packet(Ssh ssh, int pkttype, ...)
1309 {
1310 va_list ap1, ap2;
1311 va_start(ap1, pkttype);
1312 va_start(ap2, pkttype);
1313 construct_packet(ssh, pkttype, ap1, ap2);
1314 s_wrpkt(ssh);
1315 }
1316
1317 static void defer_packet(Ssh ssh, int pkttype, ...)
1318 {
1319 va_list ap1, ap2;
1320 va_start(ap1, pkttype);
1321 va_start(ap2, pkttype);
1322 construct_packet(ssh, pkttype, ap1, ap2);
1323 s_wrpkt_defer(ssh);
1324 }
1325
1326 static int ssh_versioncmp(char *a, char *b)
1327 {
1328 char *ae, *be;
1329 unsigned long av, bv;
1330
1331 av = strtoul(a, &ae, 10);
1332 bv = strtoul(b, &be, 10);
1333 if (av != bv)
1334 return (av < bv ? -1 : +1);
1335 if (*ae == '.')
1336 ae++;
1337 if (*be == '.')
1338 be++;
1339 av = strtoul(ae, &ae, 10);
1340 bv = strtoul(be, &be, 10);
1341 if (av != bv)
1342 return (av < bv ? -1 : +1);
1343 return 0;
1344 }
1345
1346 /*
1347 * Utility routines for putting an SSH-protocol `string' and
1348 * `uint32' into a SHA state.
1349 */
1350 #include <stdio.h>
1351 static void sha_string(SHA_State * s, void *str, int len)
1352 {
1353 unsigned char lenblk[4];
1354 PUT_32BIT(lenblk, len);
1355 SHA_Bytes(s, lenblk, 4);
1356 SHA_Bytes(s, str, len);
1357 }
1358
1359 static void sha_uint32(SHA_State * s, unsigned i)
1360 {
1361 unsigned char intblk[4];
1362 PUT_32BIT(intblk, i);
1363 SHA_Bytes(s, intblk, 4);
1364 }
1365
1366 /*
1367 * SSH2 packet construction functions.
1368 */
1369 static void ssh2_pkt_ensure(Ssh ssh, int length)
1370 {
1371 if (ssh->pktout.maxlen < length) {
1372 ssh->pktout.maxlen = length + 256;
1373 ssh->pktout.data = srealloc(ssh->pktout.data,
1374 ssh->pktout.maxlen + APIEXTRA);
1375 if (!ssh->pktout.data)
1376 fatalbox("Out of memory");
1377 }
1378 }
1379 static void ssh2_pkt_adddata(Ssh ssh, void *data, int len)
1380 {
1381 ssh->pktout.length += len;
1382 ssh2_pkt_ensure(ssh, ssh->pktout.length);
1383 memcpy(ssh->pktout.data + ssh->pktout.length - len, data, len);
1384 }
1385 static void ssh2_pkt_addbyte(Ssh ssh, unsigned char byte)
1386 {
1387 ssh2_pkt_adddata(ssh, &byte, 1);
1388 }
1389 static void ssh2_pkt_init(Ssh ssh, int pkt_type)
1390 {
1391 ssh->pktout.length = 5;
1392 ssh2_pkt_addbyte(ssh, (unsigned char) pkt_type);
1393 }
1394 static void ssh2_pkt_addbool(Ssh ssh, unsigned char value)
1395 {
1396 ssh2_pkt_adddata(ssh, &value, 1);
1397 }
1398 static void ssh2_pkt_adduint32(Ssh ssh, unsigned long value)
1399 {
1400 unsigned char x[4];
1401 PUT_32BIT(x, value);
1402 ssh2_pkt_adddata(ssh, x, 4);
1403 }
1404 static void ssh2_pkt_addstring_start(Ssh ssh)
1405 {
1406 ssh2_pkt_adduint32(ssh, 0);
1407 ssh->pktout.savedpos = ssh->pktout.length;
1408 }
1409 static void ssh2_pkt_addstring_str(Ssh ssh, char *data)
1410 {
1411 ssh2_pkt_adddata(ssh, data, strlen(data));
1412 PUT_32BIT(ssh->pktout.data + ssh->pktout.savedpos - 4,
1413 ssh->pktout.length - ssh->pktout.savedpos);
1414 }
1415 static void ssh2_pkt_addstring_data(Ssh ssh, char *data, int len)
1416 {
1417 ssh2_pkt_adddata(ssh, data, len);
1418 PUT_32BIT(ssh->pktout.data + ssh->pktout.savedpos - 4,
1419 ssh->pktout.length - ssh->pktout.savedpos);
1420 }
1421 static void ssh2_pkt_addstring(Ssh ssh, char *data)
1422 {
1423 ssh2_pkt_addstring_start(ssh);
1424 ssh2_pkt_addstring_str(ssh, data);
1425 }
1426 static char *ssh2_mpint_fmt(Bignum b, int *len)
1427 {
1428 unsigned char *p;
1429 int i, n = (bignum_bitcount(b) + 7) / 8;
1430 p = smalloc(n + 1);
1431 if (!p)
1432 fatalbox("out of memory");
1433 p[0] = 0;
1434 for (i = 1; i <= n; i++)
1435 p[i] = bignum_byte(b, n - i);
1436 i = 0;
1437 while (i <= n && p[i] == 0 && (p[i + 1] & 0x80) == 0)
1438 i++;
1439 memmove(p, p + i, n + 1 - i);
1440 *len = n + 1 - i;
1441 return p;
1442 }
1443 static void ssh2_pkt_addmp(Ssh ssh, Bignum b)
1444 {
1445 unsigned char *p;
1446 int len;
1447 p = ssh2_mpint_fmt(b, &len);
1448 ssh2_pkt_addstring_start(ssh);
1449 ssh2_pkt_addstring_data(ssh, p, len);
1450 sfree(p);
1451 }
1452
1453 /*
1454 * Construct an SSH2 final-form packet: compress it, encrypt it,
1455 * put the MAC on it. Final packet, ready to be sent, is stored in
1456 * ssh->pktout.data. Total length is returned.
1457 */
1458 static int ssh2_pkt_construct(Ssh ssh)
1459 {
1460 int cipherblk, maclen, padding, i;
1461
1462 log_packet(PKT_OUTGOING, ssh->pktout.data[5],
1463 ssh2_pkt_type(ssh->pkt_ctx, ssh->pktout.data[5]),
1464 ssh->pktout.data + 6, ssh->pktout.length - 6);
1465
1466 /*
1467 * Compress packet payload.
1468 */
1469 {
1470 unsigned char *newpayload;
1471 int newlen;
1472 if (ssh->cscomp &&
1473 ssh->cscomp->compress(ssh->cs_comp_ctx, ssh->pktout.data + 5,
1474 ssh->pktout.length - 5,
1475 &newpayload, &newlen)) {
1476 ssh->pktout.length = 5;
1477 ssh2_pkt_adddata(ssh, newpayload, newlen);
1478 sfree(newpayload);
1479 }
1480 }
1481
1482 /*
1483 * Add padding. At least four bytes, and must also bring total
1484 * length (minus MAC) up to a multiple of the block size.
1485 */
1486 cipherblk = ssh->cscipher ? ssh->cscipher->blksize : 8; /* block size */
1487 cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */
1488 padding = 4;
1489 padding +=
1490 (cipherblk - (ssh->pktout.length + padding) % cipherblk) % cipherblk;
1491 maclen = ssh->csmac ? ssh->csmac->len : 0;
1492 ssh2_pkt_ensure(ssh, ssh->pktout.length + padding + maclen);
1493 ssh->pktout.data[4] = padding;
1494 for (i = 0; i < padding; i++)
1495 ssh->pktout.data[ssh->pktout.length + i] = random_byte();
1496 PUT_32BIT(ssh->pktout.data, ssh->pktout.length + padding - 4);
1497 if (ssh->csmac)
1498 ssh->csmac->generate(ssh->cs_mac_ctx, ssh->pktout.data,
1499 ssh->pktout.length + padding,
1500 ssh->v2_outgoing_sequence);
1501 ssh->v2_outgoing_sequence++; /* whether or not we MACed */
1502
1503 if (ssh->cscipher)
1504 ssh->cscipher->encrypt(ssh->cs_cipher_ctx,
1505 ssh->pktout.data, ssh->pktout.length + padding);
1506
1507 /* Ready-to-send packet starts at ssh->pktout.data. We return length. */
1508 return ssh->pktout.length + padding + maclen;
1509 }
1510
1511 /*
1512 * Construct and send an SSH2 packet immediately.
1513 */
1514 static void ssh2_pkt_send(Ssh ssh)
1515 {
1516 int len;
1517 int backlog;
1518 len = ssh2_pkt_construct(ssh);
1519 backlog = sk_write(ssh->s, ssh->pktout.data, len);
1520 if (backlog > SSH_MAX_BACKLOG)
1521 ssh_throttle_all(ssh, 1, backlog);
1522 }
1523
1524 /*
1525 * Construct an SSH2 packet and add it to a deferred data block.
1526 * Useful for sending multiple packets in a single sk_write() call,
1527 * to prevent a traffic-analysing listener from being able to work
1528 * out the length of any particular packet (such as the password
1529 * packet).
1530 *
1531 * Note that because SSH2 sequence-numbers its packets, this can
1532 * NOT be used as an m4-style `defer' allowing packets to be
1533 * constructed in one order and sent in another.
1534 */
1535 static void ssh2_pkt_defer(Ssh ssh)
1536 {
1537 int len = ssh2_pkt_construct(ssh);
1538 if (ssh->deferred_len + len > ssh->deferred_size) {
1539 ssh->deferred_size = ssh->deferred_len + len + 128;
1540 ssh->deferred_send_data = srealloc(ssh->deferred_send_data,
1541 ssh->deferred_size);
1542 }
1543 memcpy(ssh->deferred_send_data + ssh->deferred_len, ssh->pktout.data, len);
1544 ssh->deferred_len += len;
1545 }
1546
1547 /*
1548 * Send the whole deferred data block constructed by
1549 * ssh2_pkt_defer() or SSH1's defer_packet().
1550 */
1551 static void ssh_pkt_defersend(Ssh ssh)
1552 {
1553 int backlog;
1554 backlog = sk_write(ssh->s, ssh->deferred_send_data, ssh->deferred_len);
1555 ssh->deferred_len = ssh->deferred_size = 0;
1556 sfree(ssh->deferred_send_data);
1557 ssh->deferred_send_data = NULL;
1558 if (backlog > SSH_MAX_BACKLOG)
1559 ssh_throttle_all(ssh, 1, backlog);
1560 }
1561
1562 #if 0
1563 void bndebug(char *string, Bignum b)
1564 {
1565 unsigned char *p;
1566 int i, len;
1567 p = ssh2_mpint_fmt(b, &len);
1568 debug(("%s", string));
1569 for (i = 0; i < len; i++)
1570 debug((" %02x", p[i]));
1571 debug(("\n"));
1572 sfree(p);
1573 }
1574 #endif
1575
1576 static void sha_mpint(SHA_State * s, Bignum b)
1577 {
1578 unsigned char *p;
1579 int len;
1580 p = ssh2_mpint_fmt(b, &len);
1581 sha_string(s, p, len);
1582 sfree(p);
1583 }
1584
1585 /*
1586 * SSH2 packet decode functions.
1587 */
1588 static unsigned long ssh2_pkt_getuint32(Ssh ssh)
1589 {
1590 unsigned long value;
1591 if (ssh->pktin.length - ssh->pktin.savedpos < 4)
1592 return 0; /* arrgh, no way to decline (FIXME?) */
1593 value = GET_32BIT(ssh->pktin.data + ssh->pktin.savedpos);
1594 ssh->pktin.savedpos += 4;
1595 return value;
1596 }
1597 static int ssh2_pkt_getbool(Ssh ssh)
1598 {
1599 unsigned long value;
1600 if (ssh->pktin.length - ssh->pktin.savedpos < 1)
1601 return 0; /* arrgh, no way to decline (FIXME?) */
1602 value = ssh->pktin.data[ssh->pktin.savedpos] != 0;
1603 ssh->pktin.savedpos++;
1604 return value;
1605 }
1606 static void ssh2_pkt_getstring(Ssh ssh, char **p, int *length)
1607 {
1608 *p = NULL;
1609 *length = 0;
1610 if (ssh->pktin.length - ssh->pktin.savedpos < 4)
1611 return;
1612 *length = GET_32BIT(ssh->pktin.data + ssh->pktin.savedpos);
1613 ssh->pktin.savedpos += 4;
1614 if (ssh->pktin.length - ssh->pktin.savedpos < *length)
1615 return;
1616 *p = ssh->pktin.data + ssh->pktin.savedpos;
1617 ssh->pktin.savedpos += *length;
1618 }
1619 static Bignum ssh2_pkt_getmp(Ssh ssh)
1620 {
1621 char *p;
1622 int length;
1623 Bignum b;
1624
1625 ssh2_pkt_getstring(ssh, &p, &length);
1626 if (!p)
1627 return NULL;
1628 if (p[0] & 0x80) {
1629 bombout(("internal error: Can't handle negative mpints"));
1630 return NULL;
1631 }
1632 b = bignum_from_bytes(p, length);
1633 return b;
1634 }
1635
1636 /*
1637 * Helper function to add an SSH2 signature blob to a packet.
1638 * Expects to be shown the public key blob as well as the signature
1639 * blob. Normally works just like ssh2_pkt_addstring, but will
1640 * fiddle with the signature packet if necessary for
1641 * BUG_SSH2_RSA_PADDING.
1642 */
1643 static void ssh2_add_sigblob(Ssh ssh, void *pkblob_v, int pkblob_len,
1644 void *sigblob_v, int sigblob_len)
1645 {
1646 unsigned char *pkblob = (unsigned char *)pkblob_v;
1647 unsigned char *sigblob = (unsigned char *)sigblob_v;
1648
1649 /* dmemdump(pkblob, pkblob_len); */
1650 /* dmemdump(sigblob, sigblob_len); */
1651
1652 /*
1653 * See if this is in fact an ssh-rsa signature and a buggy
1654 * server; otherwise we can just do this the easy way.
1655 */
1656 if ((ssh->remote_bugs & BUG_SSH2_RSA_PADDING) &&
1657 (GET_32BIT(pkblob) == 7 && !memcmp(pkblob+4, "ssh-rsa", 7))) {
1658 int pos, len, siglen;
1659
1660 /*
1661 * Find the byte length of the modulus.
1662 */
1663
1664 pos = 4+7; /* skip over "ssh-rsa" */
1665 pos += 4 + GET_32BIT(pkblob+pos); /* skip over exponent */
1666 len = GET_32BIT(pkblob+pos); /* find length of modulus */
1667 pos += 4; /* find modulus itself */
1668 while (len > 0 && pkblob[pos] == 0)
1669 len--, pos++;
1670 /* debug(("modulus length is %d\n", len)); */
1671
1672 /*
1673 * Now find the signature integer.
1674 */
1675 pos = 4+7; /* skip over "ssh-rsa" */
1676 siglen = GET_32BIT(sigblob+pos);
1677 /* debug(("signature length is %d\n", siglen)); */
1678
1679 if (len != siglen) {
1680 unsigned char newlen[4];
1681 ssh2_pkt_addstring_start(ssh);
1682 ssh2_pkt_addstring_data(ssh, sigblob, pos);
1683 /* dmemdump(sigblob, pos); */
1684 pos += 4; /* point to start of actual sig */
1685 PUT_32BIT(newlen, len);
1686 ssh2_pkt_addstring_data(ssh, newlen, 4);
1687 /* dmemdump(newlen, 4); */
1688 newlen[0] = 0;
1689 while (len-- > siglen) {
1690 ssh2_pkt_addstring_data(ssh, newlen, 1);
1691 /* dmemdump(newlen, 1); */
1692 }
1693 ssh2_pkt_addstring_data(ssh, sigblob+pos, siglen);
1694 /* dmemdump(sigblob+pos, siglen); */
1695 return;
1696 }
1697
1698 /* Otherwise fall through and do it the easy way. */
1699 }
1700
1701 ssh2_pkt_addstring_start(ssh);
1702 ssh2_pkt_addstring_data(ssh, sigblob, sigblob_len);
1703 }
1704
1705 /*
1706 * Examine the remote side's version string and compare it against
1707 * a list of known buggy implementations.
1708 */
1709 static void ssh_detect_bugs(Ssh ssh, char *vstring)
1710 {
1711 char *imp; /* pointer to implementation part */
1712 imp = vstring;
1713 imp += strcspn(imp, "-");
1714 if (*imp) imp++;
1715 imp += strcspn(imp, "-");
1716 if (*imp) imp++;
1717
1718 ssh->remote_bugs = 0;
1719
1720 if (cfg.sshbug_ignore1 == BUG_ON ||
1721 (cfg.sshbug_ignore1 == BUG_AUTO &&
1722 (!strcmp(imp, "1.2.18") || !strcmp(imp, "1.2.19") ||
1723 !strcmp(imp, "1.2.20") || !strcmp(imp, "1.2.21") ||
1724 !strcmp(imp, "1.2.22") || !strcmp(imp, "Cisco-1.25")))) {
1725 /*
1726 * These versions don't support SSH1_MSG_IGNORE, so we have
1727 * to use a different defence against password length
1728 * sniffing.
1729 */
1730 ssh->remote_bugs |= BUG_CHOKES_ON_SSH1_IGNORE;
1731 logevent("We believe remote version has SSH1 ignore bug");
1732 }
1733
1734 if (cfg.sshbug_plainpw1 == BUG_ON ||
1735 (cfg.sshbug_plainpw1 == BUG_AUTO &&
1736 (!strcmp(imp, "Cisco-1.25")))) {
1737 /*
1738 * These versions need a plain password sent; they can't
1739 * handle having a null and a random length of data after
1740 * the password.
1741 */
1742 ssh->remote_bugs |= BUG_NEEDS_SSH1_PLAIN_PASSWORD;
1743 logevent("We believe remote version needs a plain SSH1 password");
1744 }
1745
1746 if (cfg.sshbug_rsa1 == BUG_ON ||
1747 (cfg.sshbug_rsa1 == BUG_AUTO &&
1748 (!strcmp(imp, "Cisco-1.25")))) {
1749 /*
1750 * These versions apparently have no clue whatever about
1751 * RSA authentication and will panic and die if they see
1752 * an AUTH_RSA message.
1753 */
1754 ssh->remote_bugs |= BUG_CHOKES_ON_RSA;
1755 logevent("We believe remote version can't handle RSA authentication");
1756 }
1757
1758 if (cfg.sshbug_hmac2 == BUG_ON ||
1759 (cfg.sshbug_hmac2 == BUG_AUTO &&
1760 (!strncmp(imp, "2.1.0", 5) || !strncmp(imp, "2.0.", 4) ||
1761 !strncmp(imp, "2.2.0", 5) || !strncmp(imp, "2.3.0", 5) ||
1762 !strncmp(imp, "2.1 ", 4)))) {
1763 /*
1764 * These versions have the HMAC bug.
1765 */
1766 ssh->remote_bugs |= BUG_SSH2_HMAC;
1767 logevent("We believe remote version has SSH2 HMAC bug");
1768 }
1769
1770 if (cfg.sshbug_derivekey2 == BUG_ON ||
1771 (cfg.sshbug_derivekey2 == BUG_AUTO &&
1772 (!strncmp(imp, "2.0.", 4)))) {
1773 /*
1774 * These versions have the key-derivation bug (failing to
1775 * include the literal shared secret in the hashes that
1776 * generate the keys).
1777 */
1778 ssh->remote_bugs |= BUG_SSH2_DERIVEKEY;
1779 logevent("We believe remote version has SSH2 key-derivation bug");
1780 }
1781
1782 if (cfg.sshbug_rsapad2 == BUG_ON ||
1783 (cfg.sshbug_rsapad2 == BUG_AUTO &&
1784 ((!strncmp(imp, "OpenSSH_2.", 10) && imp[10]>='5' && imp[10]<='9') ||
1785 (!strncmp(imp, "OpenSSH_3.", 10) && imp[10]>='0' && imp[10]<='2')))){
1786 /*
1787 * These versions have the SSH2 RSA padding bug.
1788 */
1789 ssh->remote_bugs |= BUG_SSH2_RSA_PADDING;
1790 logevent("We believe remote version has SSH2 RSA padding bug");
1791 }
1792
1793 if (cfg.sshbug_dhgex2 == BUG_ON) {
1794 /*
1795 * These versions have the SSH2 DH GEX bug.
1796 */
1797 ssh->remote_bugs |= BUG_SSH2_DH_GEX;
1798 logevent("We believe remote version has SSH2 DH group exchange bug");
1799 }
1800 }
1801
1802 static int do_ssh_init(Ssh ssh, unsigned char c)
1803 {
1804 struct do_ssh_init_state {
1805 int vslen;
1806 char version[10];
1807 char *vstring;
1808 int vstrsize;
1809 int i;
1810 int proto1, proto2;
1811 };
1812 crState(do_ssh_init_state);
1813
1814 crBegin(ssh->do_ssh_init_crstate);
1815
1816 /* Search for the string "SSH-" in the input. */
1817 s->i = 0;
1818 while (1) {
1819 static const int transS[] = { 1, 2, 2, 1 };
1820 static const int transH[] = { 0, 0, 3, 0 };
1821 static const int transminus[] = { 0, 0, 0, -1 };
1822 if (c == 'S')
1823 s->i = transS[s->i];
1824 else if (c == 'H')
1825 s->i = transH[s->i];
1826 else if (c == '-')
1827 s->i = transminus[s->i];
1828 else
1829 s->i = 0;
1830 if (s->i < 0)
1831 break;
1832 crReturn(1); /* get another character */
1833 }
1834
1835 s->vstrsize = 16;
1836 s->vstring = smalloc(s->vstrsize);
1837 strcpy(s->vstring, "SSH-");
1838 s->vslen = 4;
1839 s->i = 0;
1840 while (1) {
1841 crReturn(1); /* get another char */
1842 if (s->vslen >= s->vstrsize - 1) {
1843 s->vstrsize += 16;
1844 s->vstring = srealloc(s->vstring, s->vstrsize);
1845 }
1846 s->vstring[s->vslen++] = c;
1847 if (s->i >= 0) {
1848 if (c == '-') {
1849 s->version[s->i] = '\0';
1850 s->i = -1;
1851 } else if (s->i < sizeof(s->version) - 1)
1852 s->version[s->i++] = c;
1853 } else if (c == '\n')
1854 break;
1855 }
1856
1857 ssh->agentfwd_enabled = FALSE;
1858 ssh->rdpkt2_state.incoming_sequence = 0;
1859
1860 s->vstring[s->vslen] = 0;
1861 s->vstring[strcspn(s->vstring, "\r\n")] = '\0';/* remove EOL chars */
1862 {
1863 char *vlog;
1864 vlog = smalloc(20 + s->vslen);
1865 sprintf(vlog, "Server version: %s", s->vstring);
1866 logevent(vlog);
1867 sfree(vlog);
1868 }
1869 ssh_detect_bugs(ssh, s->vstring);
1870
1871 /*
1872 * Decide which SSH protocol version to support.
1873 */
1874
1875 /* Anything strictly below "2.0" means protocol 1 is supported. */
1876 s->proto1 = ssh_versioncmp(s->version, "2.0") < 0;
1877 /* Anything greater or equal to "1.99" means protocol 2 is supported. */
1878 s->proto2 = ssh_versioncmp(s->version, "1.99") >= 0;
1879
1880 if (cfg.sshprot == 0 && !s->proto1) {
1881 bombout(("SSH protocol version 1 required by user but not provided by server"));
1882 crReturn(0);
1883 }
1884 if (cfg.sshprot == 3 && !s->proto2) {
1885 bombout(("SSH protocol version 2 required by user but not provided by server"));
1886 crReturn(0);
1887 }
1888
1889 if (s->proto2 && (cfg.sshprot >= 2 || !s->proto1)) {
1890 /*
1891 * Use v2 protocol.
1892 */
1893 char verstring[80], vlog[100];
1894 sprintf(verstring, "SSH-2.0-%s", sshver);
1895 SHA_Init(&ssh->exhashbase);
1896 /*
1897 * Hash our version string and their version string.
1898 */
1899 sha_string(&ssh->exhashbase, verstring, strlen(verstring));
1900 sha_string(&ssh->exhashbase, s->vstring, strcspn(s->vstring, "\r\n"));
1901 sprintf(vlog, "We claim version: %s", verstring);
1902 logevent(vlog);
1903 strcat(verstring, "\n");
1904 logevent("Using SSH protocol version 2");
1905 sk_write(ssh->s, verstring, strlen(verstring));
1906 ssh->protocol = ssh2_protocol;
1907 ssh->version = 2;
1908 ssh->s_rdpkt = ssh2_rdpkt;
1909 } else {
1910 /*
1911 * Use v1 protocol.
1912 */
1913 char verstring[80], vlog[100];
1914 sprintf(verstring, "SSH-%s-%s",
1915 (ssh_versioncmp(s->version, "1.5") <= 0 ? s->version : "1.5"),
1916 sshver);
1917 sprintf(vlog, "We claim version: %s", verstring);
1918 logevent(vlog);
1919 strcat(verstring, "\n");
1920
1921 logevent("Using SSH protocol version 1");
1922 sk_write(ssh->s, verstring, strlen(verstring));
1923 ssh->protocol = ssh1_protocol;
1924 ssh->version = 1;
1925 ssh->s_rdpkt = ssh1_rdpkt;
1926 }
1927 ssh->state = SSH_STATE_BEFORE_SIZE;
1928
1929 sfree(s->vstring);
1930
1931 crFinish(0);
1932 }
1933
1934 static void ssh_gotdata(Ssh ssh, unsigned char *data, int datalen)
1935 {
1936 crBegin(ssh->ssh_gotdata_crstate);
1937
1938 /*
1939 * To begin with, feed the characters one by one to the
1940 * protocol initialisation / selection function do_ssh_init().
1941 * When that returns 0, we're done with the initial greeting
1942 * exchange and can move on to packet discipline.
1943 */
1944 while (1) {
1945 int ret; /* need not be kept across crReturn */
1946 if (datalen == 0)
1947 crReturnV; /* more data please */
1948 ret = do_ssh_init(ssh, *data);
1949 data++;
1950 datalen--;
1951 if (ret == 0)
1952 break;
1953 }
1954
1955 /*
1956 * We emerge from that loop when the initial negotiation is
1957 * over and we have selected an s_rdpkt function. Now pass
1958 * everything to s_rdpkt, and then pass the resulting packets
1959 * to the proper protocol handler.
1960 */
1961 if (datalen == 0)
1962 crReturnV;
1963 while (1) {
1964 while (datalen > 0) {
1965 if (ssh->s_rdpkt(ssh, &data, &datalen) == 0) {
1966 if (ssh->state == SSH_STATE_CLOSED) {
1967 return;
1968 }
1969 ssh->protocol(ssh, NULL, 0, 1);
1970 if (ssh->state == SSH_STATE_CLOSED) {
1971 return;
1972 }
1973 }
1974 }
1975 crReturnV;
1976 }
1977 crFinishV;
1978 }
1979
1980 static int ssh_closing(Plug plug, char *error_msg, int error_code,
1981 int calling_back)
1982 {
1983 Ssh ssh = (Ssh) plug;
1984 ssh->state = SSH_STATE_CLOSED;
1985 if (ssh->s) {
1986 sk_close(ssh->s);
1987 ssh->s = NULL;
1988 }
1989 if (error_msg) {
1990 /* A socket error has occurred. */
1991 logevent(error_msg);
1992 connection_fatal(error_msg);
1993 } else {
1994 /* Otherwise, the remote side closed the connection normally. */
1995 }
1996 return 0;
1997 }
1998
1999 static int ssh_receive(Plug plug, int urgent, char *data, int len)
2000 {
2001 Ssh ssh = (Ssh) plug;
2002 ssh_gotdata(ssh, data, len);
2003 if (ssh->state == SSH_STATE_CLOSED) {
2004 if (ssh->s) {
2005 sk_close(ssh->s);
2006 ssh->s = NULL;
2007 }
2008 return 0;
2009 }
2010 return 1;
2011 }
2012
2013 static void ssh_sent(Plug plug, int bufsize)
2014 {
2015 Ssh ssh = (Ssh) plug;
2016 /*
2017 * If the send backlog on the SSH socket itself clears, we
2018 * should unthrottle the whole world if it was throttled.
2019 */
2020 if (bufsize < SSH_MAX_BACKLOG)
2021 ssh_throttle_all(ssh, 0, bufsize);
2022 }
2023
2024 /*
2025 * Connect to specified host and port.
2026 * Returns an error message, or NULL on success.
2027 * Also places the canonical host name into `realhost'. It must be
2028 * freed by the caller.
2029 */
2030 static char *connect_to_host(Ssh ssh, char *host, int port,
2031 char **realhost, int nodelay)
2032 {
2033 static const struct plug_function_table fn_table = {
2034 ssh_closing,
2035 ssh_receive,
2036 ssh_sent,
2037 NULL
2038 };
2039
2040 SockAddr addr;
2041 char *err;
2042
2043 ssh->savedhost = smalloc(1 + strlen(host));
2044 if (!ssh->savedhost)
2045 fatalbox("Out of memory");
2046 strcpy(ssh->savedhost, host);
2047
2048 if (port < 0)
2049 port = 22; /* default ssh port */
2050 ssh->savedport = port;
2051
2052 /*
2053 * Try to find host.
2054 */
2055 {
2056 char buf[200];
2057 sprintf(buf, "Looking up host \"%.170s\"", host);
2058 logevent(buf);
2059 }
2060 addr = sk_namelookup(host, realhost);
2061 if ((err = sk_addr_error(addr)))
2062 return err;
2063
2064 /*
2065 * Open socket.
2066 */
2067 {
2068 char buf[200], addrbuf[100];
2069 sk_getaddr(addr, addrbuf, 100);
2070 sprintf(buf, "Connecting to %.100s port %d", addrbuf, port);
2071 logevent(buf);
2072 }
2073 ssh->fn = &fn_table;
2074 ssh->s = new_connection(addr, *realhost, port, 0, 1, nodelay, (Plug) ssh);
2075 if ((err = sk_socket_error(ssh->s))) {
2076 ssh->s = NULL;
2077 return err;
2078 }
2079
2080 return NULL;
2081 }
2082
2083 /*
2084 * Throttle or unthrottle the SSH connection.
2085 */
2086 static void ssh1_throttle(Ssh ssh, int adjust)
2087 {
2088 int old_count = ssh->v1_throttle_count;
2089 ssh->v1_throttle_count += adjust;
2090 assert(ssh->v1_throttle_count >= 0);
2091 if (ssh->v1_throttle_count && !old_count) {
2092 sk_set_frozen(ssh->s, 1);
2093 } else if (!ssh->v1_throttle_count && old_count) {
2094 sk_set_frozen(ssh->s, 0);
2095 }
2096 }
2097
2098 /*
2099 * Throttle or unthrottle _all_ local data streams (for when sends
2100 * on the SSH connection itself back up).
2101 */
2102 static void ssh_throttle_all(Ssh ssh, int enable, int bufsize)
2103 {
2104 int i;
2105 struct ssh_channel *c;
2106
2107 if (enable == ssh->throttled_all)
2108 return;
2109 ssh->throttled_all = enable;
2110 ssh->overall_bufsize = bufsize;
2111 if (!ssh->channels)
2112 return;
2113 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
2114 switch (c->type) {
2115 case CHAN_MAINSESSION:
2116 /*
2117 * This is treated separately, outside the switch.
2118 */
2119 break;
2120 case CHAN_X11:
2121 x11_override_throttle(c->u.x11.s, enable);
2122 break;
2123 case CHAN_AGENT:
2124 /* Agent channels require no buffer management. */
2125 break;
2126 case CHAN_SOCKDATA:
2127 pfd_override_throttle(c->u.x11.s, enable);
2128 break;
2129 }
2130 }
2131 }
2132
2133 /*
2134 * Username and password input, abstracted off into routines
2135 * reusable in several places - even between SSH1 and SSH2.
2136 */
2137
2138 /* Set up a username or password input loop on a given buffer. */
2139 void setup_userpass_input(Ssh ssh, char *buffer, int buflen, int echo)
2140 {
2141 ssh->userpass_input_buffer = buffer;
2142 ssh->userpass_input_buflen = buflen;
2143 ssh->userpass_input_bufpos = 0;
2144 ssh->userpass_input_echo = echo;
2145 }
2146
2147 /*
2148 * Process some terminal data in the course of username/password
2149 * input. Returns >0 for success (line of input returned in
2150 * buffer), <0 for failure (user hit ^C/^D, bomb out and exit), 0
2151 * for inconclusive (keep waiting for more input please).
2152 */
2153 int process_userpass_input(Ssh ssh, unsigned char *in, int inlen)
2154 {
2155 char c;
2156
2157 while (inlen--) {
2158 switch (c = *in++) {
2159 case 10:
2160 case 13:
2161 ssh->userpass_input_buffer[ssh->userpass_input_bufpos] = 0;
2162 ssh->userpass_input_buffer[ssh->userpass_input_buflen-1] = 0;
2163 return +1;
2164 break;
2165 case 8:
2166 case 127:
2167 if (ssh->userpass_input_bufpos > 0) {
2168 if (ssh->userpass_input_echo)
2169 c_write_str(ssh, "\b \b");
2170 ssh->userpass_input_bufpos--;
2171 }
2172 break;
2173 case 21:
2174 case 27:
2175 while (ssh->userpass_input_bufpos > 0) {
2176 if (ssh->userpass_input_echo)
2177 c_write_str(ssh, "\b \b");
2178 ssh->userpass_input_bufpos--;
2179 }
2180 break;
2181 case 3:
2182 case 4:
2183 return -1;
2184 break;
2185 default:
2186 if (((c >= ' ' && c <= '~') ||
2187 ((unsigned char) c >= 160))
2188 && ssh->userpass_input_bufpos < ssh->userpass_input_buflen-1) {
2189 ssh->userpass_input_buffer[ssh->userpass_input_bufpos++] = c;
2190 if (ssh->userpass_input_echo)
2191 c_write(ssh, &c, 1);
2192 }
2193 break;
2194 }
2195 }
2196 return 0;
2197 }
2198
2199 /*
2200 * Handle the key exchange and user authentication phases.
2201 */
2202 static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
2203 {
2204 int i, j;
2205 unsigned char cookie[8];
2206 struct RSAKey servkey, hostkey;
2207 struct MD5Context md5c;
2208 struct do_ssh1_login_state {
2209 int len;
2210 unsigned char *rsabuf, *keystr1, *keystr2;
2211 unsigned long supported_ciphers_mask, supported_auths_mask;
2212 int tried_publickey, tried_agent;
2213 int tis_auth_refused, ccard_auth_refused;
2214 unsigned char session_id[16];
2215 int cipher_type;
2216 char username[100];
2217 void *publickey_blob;
2218 int publickey_bloblen;
2219 char password[100];
2220 char prompt[200];
2221 int pos;
2222 char c;
2223 int pwpkt_type;
2224 unsigned char request[5], *response, *p;
2225 int responselen;
2226 int keyi, nkeys;
2227 int authed;
2228 struct RSAKey key;
2229 Bignum challenge;
2230 char *commentp;
2231 int commentlen;
2232 };
2233 crState(do_ssh1_login_state);
2234
2235 crBegin(ssh->do_ssh1_login_crstate);
2236
2237 if (!ispkt)
2238 crWaitUntil(ispkt);
2239
2240 if (ssh->pktin.type != SSH1_SMSG_PUBLIC_KEY) {
2241 bombout(("Public key packet not received"));
2242 crReturn(0);
2243 }
2244
2245 logevent("Received public keys");
2246
2247 memcpy(cookie, ssh->pktin.body, 8);
2248
2249 i = makekey(ssh->pktin.body + 8, &servkey, &s->keystr1, 0);
2250 j = makekey(ssh->pktin.body + 8 + i, &hostkey, &s->keystr2, 0);
2251
2252 /*
2253 * Log the host key fingerprint.
2254 */
2255 {
2256 char logmsg[80];
2257 logevent("Host key fingerprint is:");
2258 strcpy(logmsg, " ");
2259 hostkey.comment = NULL;
2260 rsa_fingerprint(logmsg + strlen(logmsg),
2261 sizeof(logmsg) - strlen(logmsg), &hostkey);
2262 logevent(logmsg);
2263 }
2264
2265 ssh->v1_remote_protoflags = GET_32BIT(ssh->pktin.body + 8 + i + j);
2266 s->supported_ciphers_mask = GET_32BIT(ssh->pktin.body + 12 + i + j);
2267 s->supported_auths_mask = GET_32BIT(ssh->pktin.body + 16 + i + j);
2268
2269 ssh->v1_local_protoflags =
2270 ssh->v1_remote_protoflags & SSH1_PROTOFLAGS_SUPPORTED;
2271 ssh->v1_local_protoflags |= SSH1_PROTOFLAG_SCREEN_NUMBER;
2272
2273 MD5Init(&md5c);
2274 MD5Update(&md5c, s->keystr2, hostkey.bytes);
2275 MD5Update(&md5c, s->keystr1, servkey.bytes);
2276 MD5Update(&md5c, ssh->pktin.body, 8);
2277 MD5Final(s->session_id, &md5c);
2278
2279 for (i = 0; i < 32; i++)
2280 ssh->session_key[i] = random_byte();
2281
2282 s->len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes);
2283
2284 s->rsabuf = smalloc(s->len);
2285 if (!s->rsabuf)
2286 fatalbox("Out of memory");
2287
2288 /*
2289 * Verify the host key.
2290 */
2291 {
2292 /*
2293 * First format the key into a string.
2294 */
2295 int len = rsastr_len(&hostkey);
2296 char fingerprint[100];
2297 char *keystr = smalloc(len);
2298 if (!keystr)
2299 fatalbox("Out of memory");
2300 rsastr_fmt(keystr, &hostkey);
2301 rsa_fingerprint(fingerprint, sizeof(fingerprint), &hostkey);
2302 verify_ssh_host_key(ssh->savedhost, ssh->savedport, "rsa", keystr,
2303 fingerprint);
2304 sfree(keystr);
2305 }
2306
2307 for (i = 0; i < 32; i++) {
2308 s->rsabuf[i] = ssh->session_key[i];
2309 if (i < 16)
2310 s->rsabuf[i] ^= s->session_id[i];
2311 }
2312
2313 if (hostkey.bytes > servkey.bytes) {
2314 rsaencrypt(s->rsabuf, 32, &servkey);
2315 rsaencrypt(s->rsabuf, servkey.bytes, &hostkey);
2316 } else {
2317 rsaencrypt(s->rsabuf, 32, &hostkey);
2318 rsaencrypt(s->rsabuf, hostkey.bytes, &servkey);
2319 }
2320
2321 logevent("Encrypted session key");
2322
2323 {
2324 int cipher_chosen = 0, warn = 0;
2325 char *cipher_string = NULL;
2326 int i;
2327 for (i = 0; !cipher_chosen && i < CIPHER_MAX; i++) {
2328 int next_cipher = cfg.ssh_cipherlist[i];
2329 if (next_cipher == CIPHER_WARN) {
2330 /* If/when we choose a cipher, warn about it */
2331 warn = 1;
2332 } else if (next_cipher == CIPHER_AES) {
2333 /* XXX Probably don't need to mention this. */
2334 logevent("AES not supported in SSH1, skipping");
2335 } else {
2336 switch (next_cipher) {
2337 case CIPHER_3DES: s->cipher_type = SSH_CIPHER_3DES;
2338 cipher_string = "3DES"; break;
2339 case CIPHER_BLOWFISH: s->cipher_type = SSH_CIPHER_BLOWFISH;
2340 cipher_string = "Blowfish"; break;
2341 case CIPHER_DES: s->cipher_type = SSH_CIPHER_DES;
2342 cipher_string = "single-DES"; break;
2343 }
2344 if (s->supported_ciphers_mask & (1 << s->cipher_type))
2345 cipher_chosen = 1;
2346 }
2347 }
2348 if (!cipher_chosen) {
2349 if ((s->supported_ciphers_mask & (1 << SSH_CIPHER_3DES)) == 0)
2350 bombout(("Server violates SSH 1 protocol by not "
2351 "supporting 3DES encryption"));
2352 else
2353 /* shouldn't happen */
2354 bombout(("No supported ciphers found"));
2355 crReturn(0);
2356 }
2357
2358 /* Warn about chosen cipher if necessary. */
2359 if (warn)
2360 askcipher(cipher_string, 0);
2361 }
2362
2363 switch (s->cipher_type) {
2364 case SSH_CIPHER_3DES:
2365 logevent("Using 3DES encryption");
2366 break;
2367 case SSH_CIPHER_DES:
2368 logevent("Using single-DES encryption");
2369 break;
2370 case SSH_CIPHER_BLOWFISH:
2371 logevent("Using Blowfish encryption");
2372 break;
2373 }
2374
2375 send_packet(ssh, SSH1_CMSG_SESSION_KEY,
2376 PKT_CHAR, s->cipher_type,
2377 PKT_DATA, cookie, 8,
2378 PKT_CHAR, (s->len * 8) >> 8, PKT_CHAR, (s->len * 8) & 0xFF,
2379 PKT_DATA, s->rsabuf, s->len,
2380 PKT_INT, ssh->v1_local_protoflags, PKT_END);
2381
2382 logevent("Trying to enable encryption...");
2383
2384 sfree(s->rsabuf);
2385
2386 ssh->cipher = (s->cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 :
2387 s->cipher_type == SSH_CIPHER_DES ? &ssh_des :
2388 &ssh_3des);
2389 ssh->v1_cipher_ctx = ssh->cipher->make_context();
2390 ssh->cipher->sesskey(ssh->v1_cipher_ctx, ssh->session_key);
2391 {
2392 char buf[256];
2393 sprintf(buf, "Initialised %.200s encryption", ssh->cipher->text_name);
2394 logevent(buf);
2395 }
2396
2397 ssh->crcda_ctx = crcda_make_context();
2398 logevent("Installing CRC compensation attack detector");
2399
2400 crWaitUntil(ispkt);
2401
2402 if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
2403 bombout(("Encryption not successfully enabled"));
2404 crReturn(0);
2405 }
2406
2407 logevent("Successfully started encryption");
2408
2409 fflush(stdout);
2410 {
2411 if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
2412 if (ssh_get_line && !ssh_getline_pw_only) {
2413 if (!ssh_get_line("login as: ",
2414 s->username, sizeof(s->username), FALSE)) {
2415 /*
2416 * get_line failed to get a username.
2417 * Terminate.
2418 */
2419 logevent("No username provided. Abandoning session.");
2420 ssh->state = SSH_STATE_CLOSED;
2421 crReturn(1);
2422 }
2423 } else {
2424 int ret; /* need not be kept over crReturn */
2425 c_write_str(ssh, "login as: ");
2426 ssh->send_ok = 1;
2427
2428 setup_userpass_input(ssh, s->username, sizeof(s->username), 1);
2429 do {
2430 crWaitUntil(!ispkt);
2431 ret = process_userpass_input(ssh, in, inlen);
2432 } while (ret == 0);
2433 if (ret < 0)
2434 cleanup_exit(0);
2435 c_write_str(ssh, "\r\n");
2436 }
2437 } else {
2438 strncpy(s->username, cfg.username, sizeof(s->username));
2439 s->username[sizeof(s->username)-1] = '\0';
2440 }
2441
2442 send_packet(ssh, SSH1_CMSG_USER, PKT_STR, s->username, PKT_END);
2443 {
2444 char userlog[22 + sizeof(s->username)];
2445 sprintf(userlog, "Sent username \"%s\"", s->username);
2446 logevent(userlog);
2447 if (flags & FLAG_INTERACTIVE &&
2448 (!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) {
2449 strcat(userlog, "\r\n");
2450 c_write_str(ssh, userlog);
2451 }
2452 }
2453 }
2454
2455 crWaitUntil(ispkt);
2456
2457 if ((ssh->remote_bugs & BUG_CHOKES_ON_RSA)) {
2458 /* We must not attempt PK auth. Pretend we've already tried it. */
2459 s->tried_publickey = s->tried_agent = 1;
2460 } else {
2461 s->tried_publickey = s->tried_agent = 0;
2462 }
2463 s->tis_auth_refused = s->ccard_auth_refused = 0;
2464 /* Load the public half of cfg.keyfile so we notice if it's in Pageant */
2465 if (*cfg.keyfile) {
2466 if (!rsakey_pubblob(cfg.keyfile,
2467 &s->publickey_blob, &s->publickey_bloblen))
2468 s->publickey_blob = NULL;
2469 } else
2470 s->publickey_blob = NULL;
2471
2472 while (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2473 s->pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
2474
2475 if (agent_exists() && !s->tried_agent) {
2476 /*
2477 * Attempt RSA authentication using Pageant.
2478 */
2479 void *r;
2480
2481 s->authed = FALSE;
2482 s->tried_agent = 1;
2483 logevent("Pageant is running. Requesting keys.");
2484
2485 /* Request the keys held by the agent. */
2486 PUT_32BIT(s->request, 1);
2487 s->request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES;
2488 agent_query(s->request, 5, &r, &s->responselen);
2489 s->response = (unsigned char *) r;
2490 if (s->response && s->responselen >= 5 &&
2491 s->response[4] == SSH1_AGENT_RSA_IDENTITIES_ANSWER) {
2492 s->p = s->response + 5;
2493 s->nkeys = GET_32BIT(s->p);
2494 s->p += 4;
2495 {
2496 char buf[64];
2497 sprintf(buf, "Pageant has %d SSH1 keys", s->nkeys);
2498 logevent(buf);
2499 }
2500 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
2501 {
2502 char buf[64];
2503 sprintf(buf, "Trying Pageant key #%d", s->keyi);
2504 logevent(buf);
2505 }
2506 if (s->publickey_blob &&
2507 !memcmp(s->p, s->publickey_blob,
2508 s->publickey_bloblen)) {
2509 logevent("This key matches configured key file");
2510 s->tried_publickey = 1;
2511 }
2512 s->p += 4;
2513 s->p += ssh1_read_bignum(s->p, &s->key.exponent);
2514 s->p += ssh1_read_bignum(s->p, &s->key.modulus);
2515 s->commentlen = GET_32BIT(s->p);
2516 s->p += 4;
2517 s->commentp = s->p;
2518 s->p += s->commentlen;
2519 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
2520 PKT_BIGNUM, s->key.modulus, PKT_END);
2521 crWaitUntil(ispkt);
2522 if (ssh->pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
2523 logevent("Key refused");
2524 continue;
2525 }
2526 logevent("Received RSA challenge");
2527 ssh1_read_bignum(ssh->pktin.body, &s->challenge);
2528 {
2529 char *agentreq, *q, *ret;
2530 void *vret;
2531 int len, retlen;
2532 len = 1 + 4; /* message type, bit count */
2533 len += ssh1_bignum_length(s->key.exponent);
2534 len += ssh1_bignum_length(s->key.modulus);
2535 len += ssh1_bignum_length(s->challenge);
2536 len += 16; /* session id */
2537 len += 4; /* response format */
2538 agentreq = smalloc(4 + len);
2539 PUT_32BIT(agentreq, len);
2540 q = agentreq + 4;
2541 *q++ = SSH1_AGENTC_RSA_CHALLENGE;
2542 PUT_32BIT(q, bignum_bitcount(s->key.modulus));
2543 q += 4;
2544 q += ssh1_write_bignum(q, s->key.exponent);
2545 q += ssh1_write_bignum(q, s->key.modulus);
2546 q += ssh1_write_bignum(q, s->challenge);
2547 memcpy(q, s->session_id, 16);
2548 q += 16;
2549 PUT_32BIT(q, 1); /* response format */
2550 agent_query(agentreq, len + 4, &vret, &retlen);
2551 ret = vret;
2552 sfree(agentreq);
2553 if (ret) {
2554 if (ret[4] == SSH1_AGENT_RSA_RESPONSE) {
2555 logevent("Sending Pageant's response");
2556 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
2557 PKT_DATA, ret + 5, 16,
2558 PKT_END);
2559 sfree(ret);
2560 crWaitUntil(ispkt);
2561 if (ssh->pktin.type == SSH1_SMSG_SUCCESS) {
2562 logevent
2563 ("Pageant's response accepted");
2564 if (flags & FLAG_VERBOSE) {
2565 c_write_str(ssh, "Authenticated using"
2566 " RSA key \"");
2567 c_write(ssh, s->commentp,
2568 s->commentlen);
2569 c_write_str(ssh, "\" from agent\r\n");
2570 }
2571 s->authed = TRUE;
2572 } else
2573 logevent
2574 ("Pageant's response not accepted");
2575 } else {
2576 logevent
2577 ("Pageant failed to answer challenge");
2578 sfree(ret);
2579 }
2580 } else {
2581 logevent("No reply received from Pageant");
2582 }
2583 }
2584 freebn(s->key.exponent);
2585 freebn(s->key.modulus);
2586 freebn(s->challenge);
2587 if (s->authed)
2588 break;
2589 }
2590 }
2591 if (s->authed)
2592 break;
2593 }
2594 if (*cfg.keyfile && !s->tried_publickey)
2595 s->pwpkt_type = SSH1_CMSG_AUTH_RSA;
2596
2597 if (cfg.try_tis_auth &&
2598 (s->supported_auths_mask & (1 << SSH1_AUTH_TIS)) &&
2599 !s->tis_auth_refused) {
2600 s->pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
2601 logevent("Requested TIS authentication");
2602 send_packet(ssh, SSH1_CMSG_AUTH_TIS, PKT_END);
2603 crWaitUntil(ispkt);
2604 if (ssh->pktin.type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
2605 logevent("TIS authentication declined");
2606 if (flags & FLAG_INTERACTIVE)
2607 c_write_str(ssh, "TIS authentication refused.\r\n");
2608 s->tis_auth_refused = 1;
2609 continue;
2610 } else {
2611 int challengelen = GET_32BIT(ssh->pktin.body);
2612 logevent("Received TIS challenge");
2613 if (challengelen > sizeof(s->prompt) - 1)
2614 challengelen = sizeof(s->prompt) - 1;/* prevent overrun */
2615 memcpy(s->prompt, ssh->pktin.body + 4, challengelen);
2616 /* Prompt heuristic comes from OpenSSH */
2617 strncpy(s->prompt + challengelen,
2618 memchr(s->prompt, '\n', challengelen) ?
2619 "": "\r\nResponse: ",
2620 (sizeof s->prompt) - challengelen);
2621 s->prompt[(sizeof s->prompt) - 1] = '\0';
2622 }
2623 }
2624 if (cfg.try_tis_auth &&
2625 (s->supported_auths_mask & (1 << SSH1_AUTH_CCARD)) &&
2626 !s->ccard_auth_refused) {
2627 s->pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE;
2628 logevent("Requested CryptoCard authentication");
2629 send_packet(ssh, SSH1_CMSG_AUTH_CCARD, PKT_END);
2630 crWaitUntil(ispkt);
2631 if (ssh->pktin.type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
2632 logevent("CryptoCard authentication declined");
2633 c_write_str(ssh, "CryptoCard authentication refused.\r\n");
2634 s->ccard_auth_refused = 1;
2635 continue;
2636 } else {
2637 int challengelen = GET_32BIT(ssh->pktin.body);
2638 logevent("Received CryptoCard challenge");
2639 if (challengelen > sizeof(s->prompt) - 1)
2640 challengelen = sizeof(s->prompt) - 1;/* prevent overrun */
2641 memcpy(s->prompt, ssh->pktin.body + 4, challengelen);
2642 strncpy(s->prompt + challengelen,
2643 memchr(s->prompt, '\n', challengelen) ?
2644 "" : "\r\nResponse: ",
2645 sizeof(s->prompt) - challengelen);
2646 s->prompt[sizeof(s->prompt) - 1] = '\0';
2647 }
2648 }
2649 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
2650 sprintf(s->prompt, "%.90s@%.90s's password: ",
2651 s->username, ssh->savedhost);
2652 }
2653 if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) {
2654 char *comment = NULL;
2655 int type;
2656 char msgbuf[256];
2657 if (flags & FLAG_VERBOSE)
2658 c_write_str(ssh, "Trying public key authentication.\r\n");
2659 sprintf(msgbuf, "Trying public key \"%.200s\"", cfg.keyfile);
2660 logevent(msgbuf);
2661 type = key_type(cfg.keyfile);
2662 if (type != SSH_KEYTYPE_SSH1) {
2663 sprintf(msgbuf, "Key is of wrong type (%s)",
2664 key_type_to_str(type));
2665 logevent(msgbuf);
2666 c_write_str(ssh, msgbuf);
2667 c_write_str(ssh, "\r\n");
2668 s->tried_publickey = 1;
2669 continue;
2670 }
2671 if (!rsakey_encrypted(cfg.keyfile, &comment)) {
2672 if (flags & FLAG_VERBOSE)
2673 c_write_str(ssh, "No passphrase required.\r\n");
2674 goto tryauth;
2675 }
2676 sprintf(s->prompt, "Passphrase for key \"%.100s\": ", comment);
2677 sfree(comment);
2678 }
2679
2680 /*
2681 * Show password prompt, having first obtained it via a TIS
2682 * or CryptoCard exchange if we're doing TIS or CryptoCard
2683 * authentication.
2684 */
2685 if (ssh_get_line) {
2686 if (!ssh_get_line(s->prompt, s->password,
2687 sizeof(s->password), TRUE)) {
2688 /*
2689 * get_line failed to get a password (for example
2690 * because one was supplied on the command line
2691 * which has already failed to work). Terminate.
2692 */
2693 send_packet(ssh, SSH1_MSG_DISCONNECT,
2694 PKT_STR, "No more passwords available to try",
2695 PKT_END);
2696 logevent("Unable to authenticate");
2697 connection_fatal("Unable to authenticate");
2698 ssh->state = SSH_STATE_CLOSED;
2699 crReturn(1);
2700 }
2701 } else {
2702 /* Prompt may have come from server. We've munged it a bit, so
2703 * we know it to be zero-terminated at least once. */
2704 int ret; /* need not be saved over crReturn */
2705 c_write_untrusted(ssh, s->prompt, strlen(s->prompt));
2706 s->pos = 0;
2707
2708 setup_userpass_input(ssh, s->password, sizeof(s->password), 0);
2709 do {
2710 crWaitUntil(!ispkt);
2711 ret = process_userpass_input(ssh, in, inlen);
2712 } while (ret == 0);
2713 if (ret < 0)
2714 cleanup_exit(0);
2715 c_write_str(ssh, "\r\n");
2716 }
2717
2718 tryauth:
2719 if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) {
2720 /*
2721 * Try public key authentication with the specified
2722 * key file.
2723 */
2724 s->tried_publickey = 1;
2725
2726 {
2727 int ret = loadrsakey(cfg.keyfile, &s->key, s->password);
2728 if (ret == 0) {
2729 c_write_str(ssh, "Couldn't load private key from ");
2730 c_write_str(ssh, cfg.keyfile);
2731 c_write_str(ssh, ".\r\n");
2732 continue; /* go and try password */
2733 }
2734 if (ret == -1) {
2735 c_write_str(ssh, "Wrong passphrase.\r\n");
2736 s->tried_publickey = 0;
2737 continue; /* try again */
2738 }
2739 }
2740
2741 /*
2742 * Send a public key attempt.
2743 */
2744 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
2745 PKT_BIGNUM, s->key.modulus, PKT_END);
2746
2747 crWaitUntil(ispkt);
2748 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2749 c_write_str(ssh, "Server refused our public key.\r\n");
2750 continue; /* go and try password */
2751 }
2752 if (ssh->pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
2753 bombout(("Bizarre response to offer of public key"));
2754 crReturn(0);
2755 }
2756
2757 {
2758 int i;
2759 unsigned char buffer[32];
2760 Bignum challenge, response;
2761
2762 ssh1_read_bignum(ssh->pktin.body, &challenge);
2763 response = rsadecrypt(challenge, &s->key);
2764 freebn(s->key.private_exponent);/* burn the evidence */
2765
2766 for (i = 0; i < 32; i++) {
2767 buffer[i] = bignum_byte(response, 31 - i);
2768 }
2769
2770 MD5Init(&md5c);
2771 MD5Update(&md5c, buffer, 32);
2772 MD5Update(&md5c, s->session_id, 16);
2773 MD5Final(buffer, &md5c);
2774
2775 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
2776 PKT_DATA, buffer, 16, PKT_END);
2777
2778 freebn(challenge);
2779 freebn(response);
2780 }
2781
2782 crWaitUntil(ispkt);
2783 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2784 if (flags & FLAG_VERBOSE)
2785 c_write_str(ssh, "Failed to authenticate with"
2786 " our public key.\r\n");
2787 continue; /* go and try password */
2788 } else if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
2789 bombout(("Bizarre response to RSA authentication response"));
2790 crReturn(0);
2791 }
2792
2793 break; /* we're through! */
2794 } else {
2795 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
2796 /*
2797 * Defence against traffic analysis: we send a
2798 * whole bunch of packets containing strings of
2799 * different lengths. One of these strings is the
2800 * password, in a SSH1_CMSG_AUTH_PASSWORD packet.
2801 * The others are all random data in
2802 * SSH1_MSG_IGNORE packets. This way a passive
2803 * listener can't tell which is the password, and
2804 * hence can't deduce the password length.
2805 *
2806 * Anybody with a password length greater than 16
2807 * bytes is going to have enough entropy in their
2808 * password that a listener won't find it _that_
2809 * much help to know how long it is. So what we'll
2810 * do is:
2811 *
2812 * - if password length < 16, we send 15 packets
2813 * containing string lengths 1 through 15
2814 *
2815 * - otherwise, we let N be the nearest multiple
2816 * of 8 below the password length, and send 8
2817 * packets containing string lengths N through
2818 * N+7. This won't obscure the order of
2819 * magnitude of the password length, but it will
2820 * introduce a bit of extra uncertainty.
2821 *
2822 * A few servers (the old 1.2.18 through 1.2.22)
2823 * can't deal with SSH1_MSG_IGNORE. For these
2824 * servers, we need an alternative defence. We make
2825 * use of the fact that the password is interpreted
2826 * as a C string: so we can append a NUL, then some
2827 * random data.
2828 *
2829 * One server (a Cisco one) can deal with neither
2830 * SSH1_MSG_IGNORE _nor_ a padded password string.
2831 * For this server we are left with no defences
2832 * against password length sniffing.
2833 */
2834 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE)) {
2835 /*
2836 * The server can deal with SSH1_MSG_IGNORE, so
2837 * we can use the primary defence.
2838 */
2839 int bottom, top, pwlen, i;
2840 char *randomstr;
2841
2842 pwlen = strlen(s->password);
2843 if (pwlen < 16) {
2844 bottom = 0; /* zero length passwords are OK! :-) */
2845 top = 15;
2846 } else {
2847 bottom = pwlen & ~7;
2848 top = bottom + 7;
2849 }
2850
2851 assert(pwlen >= bottom && pwlen <= top);
2852
2853 randomstr = smalloc(top + 1);
2854
2855 for (i = bottom; i <= top; i++) {
2856 if (i == pwlen)
2857 defer_packet(ssh, s->pwpkt_type,
2858 PKT_STR, s->password, PKT_END);
2859 else {
2860 for (j = 0; j < i; j++) {
2861 do {
2862 randomstr[j] = random_byte();
2863 } while (randomstr[j] == '\0');
2864 }
2865 randomstr[i] = '\0';
2866 defer_packet(ssh, SSH1_MSG_IGNORE,
2867 PKT_STR, randomstr, PKT_END);
2868 }
2869 }
2870 logevent("Sending password with camouflage packets");
2871 ssh_pkt_defersend(ssh);
2872 }
2873 else if (!(ssh->remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) {
2874 /*
2875 * The server can't deal with SSH1_MSG_IGNORE
2876 * but can deal with padded passwords, so we
2877 * can use the secondary defence.
2878 */
2879 char string[64];
2880 char *ss;
2881 int len;
2882
2883 len = strlen(s->password);
2884 if (len < sizeof(string)) {
2885 ss = string;
2886 strcpy(string, s->password);
2887 len++; /* cover the zero byte */
2888 while (len < sizeof(string)) {
2889 string[len++] = (char) random_byte();
2890 }
2891 } else {
2892 ss = s->password;
2893 }
2894 logevent("Sending length-padded password");
2895 send_packet(ssh, s->pwpkt_type, PKT_INT, len,
2896 PKT_DATA, ss, len, PKT_END);
2897 } else {
2898 /*
2899 * The server has _both_
2900 * BUG_CHOKES_ON_SSH1_IGNORE and
2901 * BUG_NEEDS_SSH1_PLAIN_PASSWORD. There is
2902 * therefore nothing we can do.
2903 */
2904 int len;
2905 len = strlen(s->password);
2906 logevent("Sending unpadded password");
2907 send_packet(ssh, s->pwpkt_type, PKT_INT, len,
2908 PKT_DATA, s->password, len, PKT_END);
2909 }
2910 } else {
2911 send_packet(ssh, s->pwpkt_type, PKT_STR, s->password, PKT_END);
2912 }
2913 }
2914 logevent("Sent password");
2915 memset(s->password, 0, strlen(s->password));
2916 crWaitUntil(ispkt);
2917 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2918 if (flags & FLAG_VERBOSE)
2919 c_write_str(ssh, "Access denied\r\n");
2920 logevent("Authentication refused");
2921 } else if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
2922 bombout(("Strange packet received, type %d", ssh->pktin.type));
2923 crReturn(0);
2924 }
2925 }
2926
2927 logevent("Authentication successful");
2928
2929 crFinish(1);
2930 }
2931
2932 void sshfwd_close(struct ssh_channel *c)
2933 {
2934 Ssh ssh = c->ssh;
2935
2936 if (c && !c->closes) {
2937 /*
2938 * If the channel's remoteid is -1, we have sent
2939 * CHANNEL_OPEN for this channel, but it hasn't even been
2940 * acknowledged by the server. So we must set a close flag
2941 * on it now, and then when the server acks the channel
2942 * open, we can close it then.
2943 */
2944 if (((int)c->remoteid) != -1) {
2945 if (ssh->version == 1) {
2946 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid,
2947 PKT_END);
2948 } else {
2949 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
2950 ssh2_pkt_adduint32(ssh, c->remoteid);
2951 ssh2_pkt_send(ssh);
2952 }
2953 }
2954 c->closes = 1; /* sent MSG_CLOSE */
2955 if (c->type == CHAN_X11) {
2956 c->u.x11.s = NULL;
2957 logevent("Forwarded X11 connection terminated");
2958 } else if (c->type == CHAN_SOCKDATA ||
2959 c->type == CHAN_SOCKDATA_DORMANT) {
2960 c->u.pfd.s = NULL;
2961 logevent("Forwarded port closed");
2962 }
2963 }
2964 }
2965
2966 int sshfwd_write(struct ssh_channel *c, char *buf, int len)
2967 {
2968 Ssh ssh = c->ssh;
2969
2970 if (ssh->version == 1) {
2971 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
2972 PKT_INT, c->remoteid,
2973 PKT_INT, len, PKT_DATA, buf, len, PKT_END);
2974 /*
2975 * In SSH1 we can return 0 here - implying that forwarded
2976 * connections are never individually throttled - because
2977 * the only circumstance that can cause throttling will be
2978 * the whole SSH connection backing up, in which case
2979 * _everything_ will be throttled as a whole.
2980 */
2981 return 0;
2982 } else {
2983 ssh2_add_channel_data(c, buf, len);
2984 return ssh2_try_send(c);
2985 }
2986 }
2987
2988 void sshfwd_unthrottle(struct ssh_channel *c, int bufsize)
2989 {
2990 Ssh ssh = c->ssh;
2991
2992 if (ssh->version == 1) {
2993 if (c->v.v1.throttling && bufsize < SSH1_BUFFER_LIMIT) {
2994 c->v.v1.throttling = 0;
2995 ssh1_throttle(ssh, -1);
2996 }
2997 } else {
2998 ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
2999 }
3000 }
3001
3002 static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
3003 {
3004 crBegin(ssh->ssh1_protocol_crstate);
3005
3006 random_init();
3007
3008 while (!do_ssh1_login(ssh, in, inlen, ispkt)) {
3009 crReturnV;
3010 }
3011 if (ssh->state == SSH_STATE_CLOSED)
3012 crReturnV;
3013
3014 if (cfg.agentfwd && agent_exists()) {
3015 logevent("Requesting agent forwarding");
3016 send_packet(ssh, SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END);
3017 do {
3018 crReturnV;
3019 } while (!ispkt);
3020 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3021 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3022 bombout(("Protocol confusion"));
3023 crReturnV;
3024 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3025 logevent("Agent forwarding refused");
3026 } else {
3027 logevent("Agent forwarding enabled");
3028 ssh->agentfwd_enabled = TRUE;
3029 }
3030 }
3031
3032 if (cfg.x11_forward) {
3033 char proto[20], data[64];
3034 logevent("Requesting X11 forwarding");
3035 ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
3036 data, sizeof(data));
3037 if (ssh->v1_local_protoflags & SSH1_PROTOFLAG_SCREEN_NUMBER) {
3038 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
3039 PKT_STR, proto, PKT_STR, data,
3040 PKT_INT, 0, PKT_END);
3041 } else {
3042 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
3043 PKT_STR, proto, PKT_STR, data, PKT_END);
3044 }
3045 do {
3046 crReturnV;
3047 } while (!ispkt);
3048 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3049 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3050 bombout(("Protocol confusion"));
3051 crReturnV;
3052 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3053 logevent("X11 forwarding refused");
3054 } else {
3055 logevent("X11 forwarding enabled");
3056 ssh->X11_fwd_enabled = TRUE;
3057 }
3058 }
3059
3060 {
3061 char type;
3062 int n;
3063 int sport,dport,sserv,dserv;
3064 char sports[256], dports[256], host[256];
3065 char buf[1024];
3066 struct servent *se;
3067
3068 ssh->rportfwds = newtree234(ssh_rportcmp_ssh1);
3069 /* Add port forwardings. */
3070 ssh->portfwd_strptr = cfg.portfwd;
3071 while (*ssh->portfwd_strptr) {
3072 type = *ssh->portfwd_strptr++;
3073 n = 0;
3074 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != '\t')
3075 sports[n++] = *ssh->portfwd_strptr++;
3076 sports[n] = 0;
3077 if (*ssh->portfwd_strptr == '\t')
3078 ssh->portfwd_strptr++;
3079 n = 0;
3080 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':')
3081 host[n++] = *ssh->portfwd_strptr++;
3082 host[n] = 0;
3083 if (*ssh->portfwd_strptr == ':')
3084 ssh->portfwd_strptr++;
3085 n = 0;
3086 while (*ssh->portfwd_strptr)
3087 dports[n++] = *ssh->portfwd_strptr++;
3088 dports[n] = 0;
3089 ssh->portfwd_strptr++;
3090 dport = atoi(dports);
3091 dserv = 0;
3092 if (dport == 0) {
3093 dserv = 1;
3094 se = getservbyname(dports, NULL);
3095 if (se != NULL) {
3096 dport = ntohs(se->s_port);
3097 } else {
3098 sprintf(buf,
3099 "Service lookup failed for destination port \"%s\"",
3100 dports);
3101 logevent(buf);
3102 }
3103 }
3104 sport = atoi(sports);
3105 sserv = 0;
3106 if (sport == 0) {
3107 sserv = 1;
3108 se = getservbyname(sports, NULL);
3109 if (se != NULL) {
3110 sport = ntohs(se->s_port);
3111 } else {
3112 sprintf(buf,
3113 "Service lookup failed for source port \"%s\"",
3114 sports);
3115 logevent(buf);
3116 }
3117 }
3118 if (sport && dport) {
3119 if (type == 'L') {
3120 pfd_addforward(host, dport, sport, ssh);
3121 sprintf(buf, "Local port %.*s%.*s%d%.*s forwarding to"
3122 " %s:%.*s%.*s%d%.*s",
3123 sserv ? strlen(sports) : 0, sports,
3124 sserv, "(", sport, sserv, ")",
3125 host,
3126 dserv ? strlen(dports) : 0, dports,
3127 dserv, "(", dport, dserv, ")");
3128 logevent(buf);
3129 } else {
3130 struct ssh_rportfwd *pf;
3131 pf = smalloc(sizeof(*pf));
3132 strcpy(pf->dhost, host);
3133 pf->dport = dport;
3134 if (add234(ssh->rportfwds, pf) != pf) {
3135 sprintf(buf,
3136 "Duplicate remote port forwarding to %s:%d",
3137 host, dport);
3138 logevent(buf);
3139 sfree(pf);
3140 } else {
3141 sprintf(buf, "Requesting remote port %.*s%.*s%d%.*s"
3142 " forward to %s:%.*s%.*s%d%.*s",
3143 sserv ? strlen(sports) : 0, sports,
3144 sserv, "(", sport, sserv, ")",
3145 host,
3146 dserv ? strlen(dports) : 0, dports,
3147 dserv, "(", dport, dserv, ")");
3148 logevent(buf);
3149 send_packet(ssh, SSH1_CMSG_PORT_FORWARD_REQUEST,
3150 PKT_INT, sport,
3151 PKT_STR, host,
3152 PKT_INT, dport,
3153 PKT_END);
3154 do {
3155 crReturnV;
3156 } while (!ispkt);
3157 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3158 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3159 bombout(("Protocol confusion"));
3160 crReturnV;
3161 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3162 c_write_str(ssh, "Server refused port"
3163 " forwarding\r\n");
3164 }
3165 logevent("Remote port forwarding enabled");
3166 }
3167 }
3168 }
3169 }
3170 }
3171
3172 if (!cfg.nopty) {
3173 send_packet(ssh, SSH1_CMSG_REQUEST_PTY,
3174 PKT_STR, cfg.termtype,
3175 PKT_INT, ssh->term_height,
3176 PKT_INT, ssh->term_width,
3177 PKT_INT, 0, PKT_INT, 0, PKT_CHAR, 0, PKT_END);
3178 ssh->state = SSH_STATE_INTERMED;
3179 do {
3180 crReturnV;
3181 } while (!ispkt);
3182 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3183 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3184 bombout(("Protocol confusion"));
3185 crReturnV;
3186 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3187 c_write_str(ssh, "Server refused to allocate pty\r\n");
3188 ssh->editing = ssh->echoing = 1;
3189 }
3190 logevent("Allocated pty");
3191 } else {
3192 ssh->editing = ssh->echoing = 1;
3193 }
3194
3195 if (cfg.compression) {
3196 send_packet(ssh, SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END);
3197 do {
3198 crReturnV;
3199 } while (!ispkt);
3200 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3201 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3202 bombout(("Protocol confusion"));
3203 crReturnV;
3204 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3205 c_write_str(ssh, "Server refused to compress\r\n");
3206 }
3207 logevent("Started compression");
3208 ssh->v1_compressing = TRUE;
3209 ssh->cs_comp_ctx = zlib_compress_init();
3210 logevent("Initialised zlib (RFC1950) compression");
3211 ssh->sc_comp_ctx = zlib_decompress_init();
3212 logevent("Initialised zlib (RFC1950) decompression");
3213 }
3214
3215 /*
3216 * Start the shell or command.
3217 *
3218 * Special case: if the first-choice command is an SSH2
3219 * subsystem (hence not usable here) and the second choice
3220 * exists, we fall straight back to that.
3221 */
3222 {
3223 char *cmd = cfg.remote_cmd_ptr;
3224
3225 if (cfg.ssh_subsys && cfg.remote_cmd_ptr2) {
3226 cmd = cfg.remote_cmd_ptr2;
3227 ssh->fallback_cmd = TRUE;
3228 }
3229 if (*cmd)
3230 send_packet(ssh, SSH1_CMSG_EXEC_CMD, PKT_STR, cmd, PKT_END);
3231 else
3232 send_packet(ssh, SSH1_CMSG_EXEC_SHELL, PKT_END);
3233 logevent("Started session");
3234 }
3235
3236 ssh->state = SSH_STATE_SESSION;
3237 if (ssh->size_needed)
3238 ssh_size(ssh, ssh->term_width, ssh->term_height);
3239 if (ssh->eof_needed)
3240 ssh_special(ssh, TS_EOF);
3241
3242 if (ssh->ldisc)
3243 ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */
3244 ssh->send_ok = 1;
3245 ssh->channels = newtree234(ssh_channelcmp);
3246 while (1) {
3247 crReturnV;
3248 if (ispkt) {
3249 if (ssh->pktin.type == SSH1_SMSG_STDOUT_DATA ||
3250 ssh->pktin.type == SSH1_SMSG_STDERR_DATA) {
3251 long len = GET_32BIT(ssh->pktin.body);
3252 int bufsize =
3253 from_backend(ssh->frontend,
3254 ssh->pktin.type == SSH1_SMSG_STDERR_DATA,
3255 ssh->pktin.body + 4, len);
3256 if (!ssh->v1_stdout_throttling && bufsize > SSH1_BUFFER_LIMIT) {
3257 ssh->v1_stdout_throttling = 1;
3258 ssh1_throttle(ssh, +1);
3259 }
3260 } else if (ssh->pktin.type == SSH1_MSG_DISCONNECT) {
3261 ssh->state = SSH_STATE_CLOSED;
3262 logevent("Received disconnect request");
3263 crReturnV;
3264 } else if (ssh->pktin.type == SSH1_SMSG_X11_OPEN) {
3265 /* Remote side is trying to open a channel to talk to our
3266 * X-Server. Give them back a local channel number. */
3267 struct ssh_channel *c;
3268
3269 logevent("Received X11 connect request");
3270 /* Refuse if X11 forwarding is disabled. */
3271 if (!ssh->X11_fwd_enabled) {
3272 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3273 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
3274 logevent("Rejected X11 connect request");
3275 } else {
3276 c = smalloc(sizeof(struct ssh_channel));
3277 c->ssh = ssh;
3278
3279 if (x11_init(&c->u.x11.s, cfg.x11_display, c,
3280 ssh->x11auth) != NULL) {
3281 logevent("opening X11 forward connection failed");
3282 sfree(c);
3283 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3284 PKT_INT, GET_32BIT(ssh->pktin.body),
3285 PKT_END);
3286 } else {
3287 logevent
3288 ("opening X11 forward connection succeeded");
3289 c->remoteid = GET_32BIT(ssh->pktin.body);
3290 c->localid = alloc_channel_id(ssh);
3291 c->closes = 0;
3292 c->v.v1.throttling = 0;
3293 c->type = CHAN_X11; /* identify channel type */
3294 add234(ssh->channels, c);
3295 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3296 PKT_INT, c->remoteid, PKT_INT,
3297 c->localid, PKT_END);
3298 logevent("Opened X11 forward channel");
3299 }
3300 }
3301 } else if (ssh->pktin.type == SSH1_SMSG_AGENT_OPEN) {
3302 /* Remote side is trying to open a channel to talk to our
3303 * agent. Give them back a local channel number. */
3304 struct ssh_channel *c;
3305
3306 /* Refuse if agent forwarding is disabled. */
3307 if (!ssh->agentfwd_enabled) {
3308 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3309 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
3310 } else {
3311 c = smalloc(sizeof(struct ssh_channel));
3312 c->ssh = ssh;
3313 c->remoteid = GET_32BIT(ssh->pktin.body);
3314 c->localid = alloc_channel_id(ssh);
3315 c->closes = 0;
3316 c->v.v1.throttling = 0;
3317 c->type = CHAN_AGENT; /* identify channel type */
3318 c->u.a.lensofar = 0;
3319 add234(ssh->channels, c);
3320 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3321 PKT_INT, c->remoteid, PKT_INT, c->localid,
3322 PKT_END);
3323 }
3324 } else if (ssh->pktin.type == SSH1_MSG_PORT_OPEN) {
3325 /* Remote side is trying to open a channel to talk to a
3326 * forwarded port. Give them back a local channel number. */
3327 struct ssh_channel *c;
3328 struct ssh_rportfwd pf;
3329 int hostsize, port;
3330 char host[256], buf[1024];
3331 char *p, *h, *e;
3332 c = smalloc(sizeof(struct ssh_channel));
3333 c->ssh = ssh;
3334
3335 hostsize = GET_32BIT(ssh->pktin.body+4);
3336 for(h = host, p = ssh->pktin.body+8; hostsize != 0; hostsize--) {
3337 if (h+1 < host+sizeof(host))
3338 *h++ = *p;
3339 p++;
3340 }
3341 *h = 0;
3342 port = GET_32BIT(p);
3343
3344 strcpy(pf.dhost, host);
3345 pf.dport = port;
3346
3347 if (find234(ssh->rportfwds, &pf, NULL) == NULL) {
3348 sprintf(buf, "Rejected remote port open request for %s:%d",
3349 host, port);
3350 logevent(buf);
3351 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3352 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
3353 } else {
3354 sprintf(buf, "Received remote port open request for %s:%d",
3355 host, port);
3356 logevent(buf);
3357 e = pfd_newconnect(&c->u.pfd.s, host, port, c);
3358 if (e != NULL) {
3359 char buf[256];
3360 sprintf(buf, "Port open failed: %s", e);
3361 logevent(buf);
3362 sfree(c);
3363 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3364 PKT_INT, GET_32BIT(ssh->pktin.body),
3365 PKT_END);
3366 } else {
3367 c->remoteid = GET_32BIT(ssh->pktin.body);
3368 c->localid = alloc_channel_id(ssh);
3369 c->closes = 0;
3370 c->v.v1.throttling = 0;
3371 c->type = CHAN_SOCKDATA; /* identify channel type */
3372 add234(ssh->channels, c);
3373 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3374 PKT_INT, c->remoteid, PKT_INT,
3375 c->localid, PKT_END);
3376 logevent("Forwarded port opened successfully");
3377 }
3378 }
3379
3380 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_OPEN_CONFIRMATION) {
3381 unsigned int remoteid = GET_32BIT(ssh->pktin.body);
3382 unsigned int localid = GET_32BIT(ssh->pktin.body+4);
3383 struct ssh_channel *c;
3384
3385 c = find234(ssh->channels, &remoteid, ssh_channelfind);
3386 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
3387 c->remoteid = localid;
3388 c->type = CHAN_SOCKDATA;
3389 c->v.v1.throttling = 0;
3390 pfd_confirm(c->u.pfd.s);
3391 }
3392
3393 if (c && c->closes) {
3394 /*
3395 * We have a pending close on this channel,
3396 * which we decided on before the server acked
3397 * the channel open. So now we know the
3398 * remoteid, we can close it again.
3399 */
3400 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE,
3401 PKT_INT, c->remoteid, PKT_END);
3402 }
3403
3404 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_OPEN_FAILURE) {
3405 unsigned int remoteid = GET_32BIT(ssh->pktin.body);
3406 unsigned int localid = GET_32BIT(ssh->pktin.body+4);
3407 struct ssh_channel *c;
3408
3409 c = find234(ssh->channels, &remoteid, ssh_channelfind);
3410 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
3411 logevent("Forwarded connection refused by server");
3412 pfd_close(c->u.pfd.s);
3413 del234(ssh->channels, c);
3414 sfree(c);
3415 }
3416
3417 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ||
3418 ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION) {
3419 /* Remote side closes a channel. */
3420 unsigned i = GET_32BIT(ssh->pktin.body);
3421 struct ssh_channel *c;
3422 c = find234(ssh->channels, &i, ssh_channelfind);
3423 if (c && ((int)c->remoteid) != -1) {
3424 int closetype;
3425 closetype =
3426 (ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ? 1 : 2);
3427
3428 if ((c->closes == 0) && (c->type == CHAN_X11)) {
3429 logevent("Forwarded X11 connection terminated");
3430 assert(c->u.x11.s != NULL);
3431 x11_close(c->u.x11.s);
3432 c->u.x11.s = NULL;
3433 }
3434 if ((c->closes == 0) && (c->type == CHAN_SOCKDATA)) {
3435 logevent("Forwarded port closed");
3436 assert(c->u.pfd.s != NULL);
3437 pfd_close(c->u.pfd.s);
3438 c->u.pfd.s = NULL;
3439 }
3440
3441 c->closes |= (closetype << 2); /* seen this message */
3442 if (!(c->closes & closetype)) {
3443 send_packet(ssh, ssh->pktin.type, PKT_INT, c->remoteid,
3444 PKT_END);
3445 c->closes |= closetype; /* sent it too */
3446 }
3447
3448 if (c->closes == 15) {
3449 del234(ssh->channels, c);
3450 sfree(c);
3451 }
3452 } else {
3453 bombout(("Received CHANNEL_CLOSE%s for %s channel %d\n",
3454 ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ? "" :
3455 "_CONFIRMATION", c ? "half-open" : "nonexistent",
3456 i));
3457 }
3458 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_DATA) {
3459 /* Data sent down one of our channels. */
3460 int i = GET_32BIT(ssh->pktin.body);
3461 int len = GET_32BIT(ssh->pktin.body + 4);
3462 unsigned char *p = ssh->pktin.body + 8;
3463 struct ssh_channel *c;
3464 c = find234(ssh->channels, &i, ssh_channelfind);
3465 if (c) {
3466 int bufsize;
3467 switch (c->type) {
3468 case CHAN_X11:
3469 bufsize = x11_send(c->u.x11.s, p, len);
3470 break;
3471 case CHAN_SOCKDATA:
3472 bufsize = pfd_send(c->u.pfd.s, p, len);
3473 break;
3474 case CHAN_AGENT:
3475 /* Data for an agent message. Buffer it. */
3476 while (len > 0) {
3477 if (c->u.a.lensofar < 4) {
3478 int l = min(4 - c->u.a.lensofar, len);
3479 memcpy(c->u.a.msglen + c->u.a.lensofar, p,
3480 l);
3481 p += l;
3482 len -= l;
3483 c->u.a.lensofar += l;
3484 }
3485 if (c->u.a.lensofar == 4) {
3486 c->u.a.totallen =
3487 4 + GET_32BIT(c->u.a.msglen);
3488 c->u.a.message = smalloc(c->u.a.totallen);
3489 memcpy(c->u.a.message, c->u.a.msglen, 4);
3490 }
3491 if (c->u.a.lensofar >= 4 && len > 0) {
3492 int l =
3493 min(c->u.a.totallen - c->u.a.lensofar,
3494 len);
3495 memcpy(c->u.a.message + c->u.a.lensofar, p,
3496 l);
3497 p += l;
3498 len -= l;
3499 c->u.a.lensofar += l;
3500 }
3501 if (c->u.a.lensofar == c->u.a.totallen) {
3502 void *reply, *sentreply;
3503 int replylen;
3504 agent_query(c->u.a.message,
3505 c->u.a.totallen, &reply,
3506 &replylen);
3507 if (reply)
3508 sentreply = reply;
3509 else {
3510 /* Fake SSH_AGENT_FAILURE. */
3511 sentreply = "\0\0\0\1\5";
3512 replylen = 5;
3513 }
3514 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
3515 PKT_INT, c->remoteid,
3516 PKT_INT, replylen,
3517 PKT_DATA, sentreply, replylen,
3518 PKT_END);
3519 if (reply)
3520 sfree(reply);
3521 sfree(c->u.a.message);
3522 c->u.a.lensofar = 0;
3523 }
3524 }
3525 bufsize = 0; /* agent channels never back up */
3526 break;
3527 }
3528 if (!c->v.v1.throttling && bufsize > SSH1_BUFFER_LIMIT) {
3529 c->v.v1.throttling = 1;
3530 ssh1_throttle(ssh, +1);
3531 }
3532 }
3533 } else if (ssh->pktin.type == SSH1_SMSG_SUCCESS) {
3534 /* may be from EXEC_SHELL on some servers */
3535 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3536 /* may be from EXEC_SHELL on some servers
3537 * if no pty is available or in other odd cases. Ignore */
3538 } else if (ssh->pktin.type == SSH1_SMSG_EXIT_STATUS) {
3539 char buf[100];
3540 ssh->exitcode = GET_32BIT(ssh->pktin.body);
3541 sprintf(buf, "Server sent command exit status %d",
3542 ssh->exitcode);
3543 logevent(buf);
3544 send_packet(ssh, SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
3545 /*
3546 * In case `helpful' firewalls or proxies tack
3547 * extra human-readable text on the end of the
3548 * session which we might mistake for another
3549 * encrypted packet, we close the session once
3550 * we've sent EXIT_CONFIRMATION.
3551 */
3552 ssh->state = SSH_STATE_CLOSED;
3553 crReturnV;
3554 } else {
3555 bombout(("Strange packet received: type %d", ssh->pktin.type));
3556 crReturnV;
3557 }
3558 } else {
3559 while (inlen > 0) {
3560 int len = min(inlen, 512);
3561 send_packet(ssh, SSH1_CMSG_STDIN_DATA,
3562 PKT_INT, len, PKT_DATA, in, len, PKT_END);
3563 in += len;
3564 inlen -= len;
3565 }
3566 }
3567 }
3568
3569 crFinishV;
3570 }
3571
3572 /*
3573 * Utility routine for decoding comma-separated strings in KEXINIT.
3574 */
3575 static int in_commasep_string(char *needle, char *haystack, int haylen)
3576 {
3577 int needlen = strlen(needle);
3578 while (1) {
3579 /*
3580 * Is it at the start of the string?
3581 */
3582 if (haylen >= needlen && /* haystack is long enough */
3583 !memcmp(needle, haystack, needlen) && /* initial match */
3584 (haylen == needlen || haystack[needlen] == ',')
3585 /* either , or EOS follows */
3586 )
3587 return 1;
3588 /*
3589 * If not, search for the next comma and resume after that.
3590 * If no comma found, terminate.
3591 */
3592 while (haylen > 0 && *haystack != ',')
3593 haylen--, haystack++;
3594 if (haylen == 0)
3595 return 0;
3596 haylen--, haystack++; /* skip over comma itself */
3597 }
3598 }
3599
3600 /*
3601 * SSH2 key creation method.
3602 */
3603 static void ssh2_mkkey(Ssh ssh, Bignum K, char *H, char *sessid, char chr,
3604 char *keyspace)
3605 {
3606 SHA_State s;
3607 /* First 20 bytes. */
3608 SHA_Init(&s);
3609 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
3610 sha_mpint(&s, K);
3611 SHA_Bytes(&s, H, 20);
3612 SHA_Bytes(&s, &chr, 1);
3613 SHA_Bytes(&s, sessid, 20);
3614 SHA_Final(&s, keyspace);
3615 /* Next 20 bytes. */
3616 SHA_Init(&s);
3617 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
3618 sha_mpint(&s, K);
3619 SHA_Bytes(&s, H, 20);
3620 SHA_Bytes(&s, keyspace, 20);
3621 SHA_Final(&s, keyspace + 20);
3622 }
3623
3624 /*
3625 * Handle the SSH2 transport layer.
3626 */
3627 static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
3628 {
3629 struct do_ssh2_transport_state {
3630 int nbits, pbits, warn;
3631 Bignum p, g, e, f, K;
3632 int kex_init_value, kex_reply_value;
3633 const struct ssh_mac **maclist;
3634 int nmacs;
3635 const struct ssh2_cipher *cscipher_tobe;
3636 const struct ssh2_cipher *sccipher_tobe;
3637 const struct ssh_mac *csmac_tobe;
3638 const struct ssh_mac *scmac_tobe;
3639 const struct ssh_compress *cscomp_tobe;
3640 const struct ssh_compress *sccomp_tobe;
3641 char *hostkeydata, *sigdata, *keystr, *fingerprint;
3642 int hostkeylen, siglen;
3643 void *hkey; /* actual host key */
3644 unsigned char exchange_hash[20];
3645 int n_preferred_ciphers;
3646 const struct ssh2_ciphers *preferred_ciphers[CIPHER_MAX];
3647 const struct ssh_compress *preferred_comp;
3648 int first_kex;
3649 };
3650 crState(do_ssh2_transport_state);
3651
3652 crBegin(ssh->do_ssh2_transport_crstate);
3653
3654 s->cscipher_tobe = s->sccipher_tobe = NULL;
3655 s->csmac_tobe = s->scmac_tobe = NULL;
3656 s->cscomp_tobe = s->sccomp_tobe = NULL;
3657
3658 random_init();
3659 s->first_kex = 1;
3660
3661 {
3662 int i;
3663 /*
3664 * Set up the preferred ciphers. (NULL => warn below here)
3665 */
3666 s->n_preferred_ciphers = 0;
3667 for (i = 0; i < CIPHER_MAX; i++) {
3668 switch (cfg.ssh_cipherlist[i]) {
3669 case CIPHER_BLOWFISH:
3670 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_blowfish;
3671 break;
3672 case CIPHER_DES:
3673 if (cfg.ssh2_des_cbc) {
3674 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_des;
3675 }
3676 break;
3677 case CIPHER_3DES:
3678 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_3des;
3679 break;
3680 case CIPHER_AES:
3681 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_aes;
3682 break;
3683 case CIPHER_WARN:
3684 /* Flag for later. Don't bother if it's the last in
3685 * the list. */
3686 if (i < CIPHER_MAX - 1) {
3687 s->preferred_ciphers[s->n_preferred_ciphers++] = NULL;
3688 }
3689 break;
3690 }
3691 }
3692 }
3693
3694 /*
3695 * Set up preferred compression.
3696 */
3697 if (cfg.compression)
3698 s->preferred_comp = &ssh_zlib;
3699 else
3700 s->preferred_comp = &ssh_comp_none;
3701
3702 /*
3703 * Be prepared to work around the buggy MAC problem.
3704 */
3705 if (ssh->remote_bugs & BUG_SSH2_HMAC)
3706 s->maclist = buggymacs, s->nmacs = lenof(buggymacs);
3707 else
3708 s->maclist = macs, s->nmacs = lenof(macs);
3709
3710 begin_key_exchange:
3711 {
3712 int i, j, cipherstr_started;
3713
3714 /*
3715 * Construct and send our key exchange packet.
3716 */
3717 ssh2_pkt_init(ssh, SSH2_MSG_KEXINIT);
3718 for (i = 0; i < 16; i++)
3719 ssh2_pkt_addbyte(ssh, (unsigned char) random_byte());
3720 /* List key exchange algorithms. */
3721 ssh2_pkt_addstring_start(ssh);
3722 for (i = 0; i < lenof(kex_algs); i++) {
3723 if (kex_algs[i] == &ssh_diffiehellman_gex &&
3724 (ssh->remote_bugs & BUG_SSH2_DH_GEX))
3725 continue;
3726 ssh2_pkt_addstring_str(ssh, kex_algs[i]->name);
3727 if (i < lenof(kex_algs) - 1)
3728 ssh2_pkt_addstring_str(ssh, ",");
3729 }
3730 /* List server host key algorithms. */
3731 ssh2_pkt_addstring_start(ssh);
3732 for (i = 0; i < lenof(hostkey_algs); i++) {
3733 ssh2_pkt_addstring_str(ssh, hostkey_algs[i]->name);
3734 if (i < lenof(hostkey_algs) - 1)
3735 ssh2_pkt_addstring_str(ssh, ",");
3736 }
3737 /* List client->server encryption algorithms. */
3738 ssh2_pkt_addstring_start(ssh);
3739 cipherstr_started = 0;
3740 for (i = 0; i < s->n_preferred_ciphers; i++) {
3741 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3742 if (!c) continue; /* warning flag */
3743 for (j = 0; j < c->nciphers; j++) {
3744 if (cipherstr_started)
3745 ssh2_pkt_addstring_str(ssh, ",");
3746 ssh2_pkt_addstring_str(ssh, c->list[j]->name);
3747 cipherstr_started = 1;
3748 }
3749 }
3750 /* List server->client encryption algorithms. */
3751 ssh2_pkt_addstring_start(ssh);
3752 cipherstr_started = 0;
3753 for (i = 0; i < s->n_preferred_ciphers; i++) {
3754 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3755 if (!c) continue; /* warning flag */
3756 for (j = 0; j < c->nciphers; j++) {
3757 if (cipherstr_started)
3758 ssh2_pkt_addstring_str(ssh, ",");
3759 ssh2_pkt_addstring_str(ssh, c->list[j]->name);
3760 cipherstr_started = 1;
3761 }
3762 }
3763 /* List client->server MAC algorithms. */
3764 ssh2_pkt_addstring_start(ssh);
3765 for (i = 0; i < s->nmacs; i++) {
3766 ssh2_pkt_addstring_str(ssh, s->maclist[i]->name);
3767 if (i < s->nmacs - 1)
3768 ssh2_pkt_addstring_str(ssh, ",");
3769 }
3770 /* List server->client MAC algorithms. */
3771 ssh2_pkt_addstring_start(ssh);
3772 for (i = 0; i < s->nmacs; i++) {
3773 ssh2_pkt_addstring_str(ssh, s->maclist[i]->name);
3774 if (i < s->nmacs - 1)
3775 ssh2_pkt_addstring_str(ssh, ",");
3776 }
3777 /* List client->server compression algorithms. */
3778 ssh2_pkt_addstring_start(ssh);
3779 for (i = 0; i < lenof(compressions) + 1; i++) {
3780 const struct ssh_compress *c =
3781 i == 0 ? s->preferred_comp : compressions[i - 1];
3782 ssh2_pkt_addstring_str(ssh, c->name);
3783 if (i < lenof(compressions))
3784 ssh2_pkt_addstring_str(ssh, ",");
3785 }
3786 /* List server->client compression algorithms. */
3787 ssh2_pkt_addstring_start(ssh);
3788 for (i = 0; i < lenof(compressions) + 1; i++) {
3789 const struct ssh_compress *c =
3790 i == 0 ? s->preferred_comp : compressions[i - 1];
3791 ssh2_pkt_addstring_str(ssh, c->name);
3792 if (i < lenof(compressions))
3793 ssh2_pkt_addstring_str(ssh, ",");
3794 }
3795 /* List client->server languages. Empty list. */
3796 ssh2_pkt_addstring_start(ssh);
3797 /* List server->client languages. Empty list. */
3798 ssh2_pkt_addstring_start(ssh);
3799 /* First KEX packet does _not_ follow, because we're not that brave. */
3800 ssh2_pkt_addbool(ssh, FALSE);
3801 /* Reserved. */
3802 ssh2_pkt_adduint32(ssh, 0);
3803 }
3804
3805 ssh->exhash = ssh->exhashbase;
3806 sha_string(&ssh->exhash, ssh->pktout.data + 5, ssh->pktout.length - 5);
3807
3808 ssh2_pkt_send(ssh);
3809
3810 if (!ispkt)
3811 crWaitUntil(ispkt);
3812 sha_string(&ssh->exhash, ssh->pktin.data + 5, ssh->pktin.length - 5);
3813
3814 /*
3815 * Now examine the other side's KEXINIT to see what we're up
3816 * to.
3817 */
3818 {
3819 char *str;
3820 int i, j, len;
3821
3822 if (ssh->pktin.type != SSH2_MSG_KEXINIT) {
3823 bombout(("expected key exchange packet from server"));
3824 crReturn(0);
3825 }
3826 ssh->kex = NULL;
3827 ssh->hostkey = NULL;
3828 s->cscipher_tobe = NULL;
3829 s->sccipher_tobe = NULL;
3830 s->csmac_tobe = NULL;
3831 s->scmac_tobe = NULL;
3832 s->cscomp_tobe = NULL;
3833 s->sccomp_tobe = NULL;
3834 ssh->pktin.savedpos += 16; /* skip garbage cookie */
3835 ssh2_pkt_getstring(ssh, &str, &len); /* key exchange algorithms */
3836 for (i = 0; i < lenof(kex_algs); i++) {
3837 if (kex_algs[i] == &ssh_diffiehellman_gex &&
3838 (ssh->remote_bugs & BUG_SSH2_DH_GEX))
3839 continue;
3840 if (in_commasep_string(kex_algs[i]->name, str, len)) {
3841 ssh->kex = kex_algs[i];
3842 break;
3843 }
3844 }
3845 ssh2_pkt_getstring(ssh, &str, &len); /* host key algorithms */
3846 for (i = 0; i < lenof(hostkey_algs); i++) {
3847 if (in_commasep_string(hostkey_algs[i]->name, str, len)) {
3848 ssh->hostkey = hostkey_algs[i];
3849 break;
3850 }
3851 }
3852 ssh2_pkt_getstring(ssh, &str, &len); /* client->server cipher */
3853 s->warn = 0;
3854 for (i = 0; i < s->n_preferred_ciphers; i++) {
3855 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3856 if (!c) {
3857 s->warn = 1;
3858 } else {
3859 for (j = 0; j < c->nciphers; j++) {
3860 if (in_commasep_string(c->list[j]->name, str, len)) {
3861 s->cscipher_tobe = c->list[j];
3862 break;
3863 }
3864 }
3865 }
3866 if (s->cscipher_tobe) {
3867 if (s->warn)
3868 askcipher(s->cscipher_tobe->name, 1);
3869 break;
3870 }
3871 }
3872 if (!s->cscipher_tobe) {
3873 bombout(("Couldn't agree a client-to-server cipher (available: %s)", str));
3874 crReturn(0);
3875 }
3876
3877 ssh2_pkt_getstring(ssh, &str, &len); /* server->client cipher */
3878 s->warn = 0;
3879 for (i = 0; i < s->n_preferred_ciphers; i++) {
3880 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3881 if (!c) {
3882 s->warn = 1;
3883 } else {
3884 for (j = 0; j < c->nciphers; j++) {
3885 if (in_commasep_string(c->list[j]->name, str, len)) {
3886 s->sccipher_tobe = c->list[j];
3887 break;
3888 }
3889 }
3890 }
3891 if (s->sccipher_tobe) {
3892 if (s->warn)
3893 askcipher(s->sccipher_tobe->name, 2);
3894 break;
3895 }
3896 }
3897 if (!s->sccipher_tobe) {
3898 bombout(("Couldn't agree a server-to-client cipher (available: %s)", str));
3899 crReturn(0);
3900 }
3901
3902 ssh2_pkt_getstring(ssh, &str, &len); /* client->server mac */
3903 for (i = 0; i < s->nmacs; i++) {
3904 if (in_commasep_string(s->maclist[i]->name, str, len)) {
3905 s->csmac_tobe = s->maclist[i];
3906 break;
3907 }
3908 }
3909 ssh2_pkt_getstring(ssh, &str, &len); /* server->client mac */
3910 for (i = 0; i < s->nmacs; i++) {
3911 if (in_commasep_string(s->maclist[i]->name, str, len)) {
3912 s->scmac_tobe = s->maclist[i];
3913 break;
3914 }
3915 }
3916 ssh2_pkt_getstring(ssh, &str, &len); /* client->server compression */
3917 for (i = 0; i < lenof(compressions) + 1; i++) {
3918 const struct ssh_compress *c =
3919 i == 0 ? s->preferred_comp : compressions[i - 1];
3920 if (in_commasep_string(c->name, str, len)) {
3921 s->cscomp_tobe = c;
3922 break;
3923 }
3924 }
3925 ssh2_pkt_getstring(ssh, &str, &len); /* server->client compression */
3926 for (i = 0; i < lenof(compressions) + 1; i++) {
3927 const struct ssh_compress *c =
3928 i == 0 ? s->preferred_comp : compressions[i - 1];
3929 if (in_commasep_string(c->name, str, len)) {
3930 s->sccomp_tobe = c;
3931 break;
3932 }
3933 }
3934 }
3935
3936 /*
3937 * Work out the number of bits of key we will need from the key
3938 * exchange. We start with the maximum key length of either
3939 * cipher...
3940 */
3941 {
3942 int csbits, scbits;
3943
3944 csbits = s->cscipher_tobe->keylen;
3945 scbits = s->sccipher_tobe->keylen;
3946 s->nbits = (csbits > scbits ? csbits : scbits);
3947 }
3948 /* The keys only have 160-bit entropy, since they're based on
3949 * a SHA-1 hash. So cap the key size at 160 bits. */
3950 if (s->nbits > 160)
3951 s->nbits = 160;
3952
3953 /*
3954 * If we're doing Diffie-Hellman group exchange, start by
3955 * requesting a group.
3956 */
3957 if (ssh->kex == &ssh_diffiehellman_gex) {
3958 logevent("Doing Diffie-Hellman group exchange");
3959 ssh->pkt_ctx |= SSH2_PKTCTX_DHGEX;
3960 /*
3961 * Work out how big a DH group we will need to allow that
3962 * much data.
3963 */
3964 s->pbits = 512 << ((s->nbits - 1) / 64);
3965 ssh2_pkt_init(ssh, SSH2_MSG_KEX_DH_GEX_REQUEST);
3966 ssh2_pkt_adduint32(ssh, s->pbits);
3967 ssh2_pkt_send(ssh);
3968
3969 crWaitUntil(ispkt);
3970 if (ssh->pktin.type != SSH2_MSG_KEX_DH_GEX_GROUP) {
3971 bombout(("expected key exchange group packet from server"));
3972 crReturn(0);
3973 }
3974 s->p = ssh2_pkt_getmp(ssh);
3975 s->g = ssh2_pkt_getmp(ssh);
3976 ssh->kex_ctx = dh_setup_group(s->p, s->g);
3977 s->kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT;
3978 s->kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY;
3979 } else {
3980 ssh->pkt_ctx |= SSH2_PKTCTX_DHGROUP1;
3981 ssh->kex_ctx = dh_setup_group1();
3982 s->kex_init_value = SSH2_MSG_KEXDH_INIT;
3983 s->kex_reply_value = SSH2_MSG_KEXDH_REPLY;
3984 }
3985
3986 logevent("Doing Diffie-Hellman key exchange");
3987 /*
3988 * Now generate and send e for Diffie-Hellman.
3989 */
3990 s->e = dh_create_e(ssh->kex_ctx, s->nbits * 2);
3991 ssh2_pkt_init(ssh, s->kex_init_value);
3992 ssh2_pkt_addmp(ssh, s->e);
3993 ssh2_pkt_send(ssh);
3994
3995 crWaitUntil(ispkt);
3996 if (ssh->pktin.type != s->kex_reply_value) {
3997 bombout(("expected key exchange reply packet from server"));
3998 crReturn(0);
3999 }
4000 ssh2_pkt_getstring(ssh, &s->hostkeydata, &s->hostkeylen);
4001 s->f = ssh2_pkt_getmp(ssh);
4002 ssh2_pkt_getstring(ssh, &s->sigdata, &s->siglen);
4003
4004 s->K = dh_find_K(ssh->kex_ctx, s->f);
4005
4006 sha_string(&ssh->exhash, s->hostkeydata, s->hostkeylen);
4007 if (ssh->kex == &ssh_diffiehellman_gex) {
4008 sha_uint32(&ssh->exhash, s->pbits);
4009 sha_mpint(&ssh->exhash, s->p);
4010 sha_mpint(&ssh->exhash, s->g);
4011 }
4012 sha_mpint(&ssh->exhash, s->e);
4013 sha_mpint(&ssh->exhash, s->f);
4014 sha_mpint(&ssh->exhash, s->K);
4015 SHA_Final(&ssh->exhash, s->exchange_hash);
4016
4017 dh_cleanup(ssh->kex_ctx);
4018
4019 #if 0
4020 debug(("Exchange hash is:\n"));
4021 dmemdump(s->exchange_hash, 20);
4022 #endif
4023
4024 s->hkey = ssh->hostkey->newkey(s->hostkeydata, s->hostkeylen);
4025 if (!s->hkey ||
4026 !ssh->hostkey->verifysig(s->hkey, s->sigdata, s->siglen,
4027 s->exchange_hash, 20)) {
4028 bombout(("Server's host key did not match the signature supplied"));
4029 crReturn(0);
4030 }
4031
4032 /*
4033 * Authenticate remote host: verify host key. (We've already
4034 * checked the signature of the exchange hash.)
4035 */
4036 s->keystr = ssh->hostkey->fmtkey(s->hkey);
4037 s->fingerprint = ssh->hostkey->fingerprint(s->hkey);
4038 verify_ssh_host_key(ssh->savedhost, ssh->savedport, ssh->hostkey->keytype,
4039 s->keystr, s->fingerprint);
4040 if (s->first_kex) { /* don't bother logging this in rekeys */
4041 logevent("Host key fingerprint is:");
4042 logevent(s->fingerprint);
4043 }
4044 sfree(s->fingerprint);
4045 sfree(s->keystr);
4046 ssh->hostkey->freekey(s->hkey);
4047
4048 /*
4049 * Send SSH2_MSG_NEWKEYS.
4050 */
4051 ssh2_pkt_init(ssh, SSH2_MSG_NEWKEYS);
4052 ssh2_pkt_send(ssh);
4053
4054 /*
4055 * Expect SSH2_MSG_NEWKEYS from server.
4056 */
4057 crWaitUntil(ispkt);
4058 if (ssh->pktin.type != SSH2_MSG_NEWKEYS) {
4059 bombout(("expected new-keys packet from server"));
4060 crReturn(0);
4061 }
4062
4063 /*
4064 * Create and initialise session keys.
4065 */
4066 if (ssh->cs_cipher_ctx)
4067 ssh->cscipher->free_context(ssh->cs_cipher_ctx);
4068 ssh->cscipher = s->cscipher_tobe;
4069 ssh->cs_cipher_ctx = ssh->cscipher->make_context();
4070
4071 if (ssh->sc_cipher_ctx)
4072 ssh->sccipher->free_context(ssh->sc_cipher_ctx);
4073 ssh->sccipher = s->sccipher_tobe;
4074 ssh->sc_cipher_ctx = ssh->sccipher->make_context();
4075
4076 if (ssh->cs_mac_ctx)
4077 ssh->csmac->free_context(ssh->cs_mac_ctx);
4078 ssh->csmac = s->csmac_tobe;
4079 ssh->cs_mac_ctx = ssh->csmac->make_context();
4080
4081 if (ssh->sc_mac_ctx)
4082 ssh->scmac->free_context(ssh->sc_mac_ctx);
4083 ssh->scmac = s->scmac_tobe;
4084 ssh->sc_mac_ctx = ssh->scmac->make_context();
4085
4086 if (ssh->cs_comp_ctx)
4087 ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
4088 ssh->cscomp = s->cscomp_tobe;
4089 ssh->cs_comp_ctx = ssh->cscomp->compress_init();
4090
4091 if (ssh->sc_comp_ctx)
4092 ssh->sccomp->decompress_cleanup(ssh->sc_comp_ctx);
4093 ssh->sccomp = s->sccomp_tobe;
4094 ssh->sc_comp_ctx = ssh->sccomp->decompress_init();
4095
4096 /*
4097 * Set IVs after keys. Here we use the exchange hash from the
4098 * _first_ key exchange.
4099 */
4100 {
4101 unsigned char keyspace[40];
4102 if (s->first_kex)
4103 memcpy(ssh->v2_session_id, s->exchange_hash,
4104 sizeof(s->exchange_hash));
4105 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'C',keyspace);
4106 ssh->cscipher->setkey(ssh->cs_cipher_ctx, keyspace);
4107 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'D',keyspace);
4108 ssh->sccipher->setkey(ssh->sc_cipher_ctx, keyspace);
4109 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'A',keyspace);
4110 ssh->cscipher->setiv(ssh->cs_cipher_ctx, keyspace);
4111 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'B',keyspace);
4112 ssh->sccipher->setiv(ssh->sc_cipher_ctx, keyspace);
4113 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'E',keyspace);
4114 ssh->csmac->setkey(ssh->cs_mac_ctx, keyspace);
4115 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'F',keyspace);
4116 ssh->scmac->setkey(ssh->sc_mac_ctx, keyspace);
4117 }
4118 {
4119 char buf[256];
4120 sprintf(buf, "Initialised %.200s client->server encryption",
4121 ssh->cscipher->text_name);
4122 logevent(buf);
4123 sprintf(buf, "Initialised %.200s server->client encryption",
4124 ssh->sccipher->text_name);
4125 logevent(buf);
4126 if (ssh->cscomp->text_name) {
4127 sprintf(buf, "Initialised %.200s compression",
4128 ssh->cscomp->text_name);
4129 logevent(buf);
4130 }
4131 if (ssh->sccomp->text_name) {
4132 sprintf(buf, "Initialised %.200s decompression",
4133 ssh->sccomp->text_name);
4134 logevent(buf);
4135 }
4136 }
4137
4138
4139 /*
4140 * If this is the first key exchange phase, we must pass the
4141 * SSH2_MSG_NEWKEYS packet to the next layer, not because it
4142 * wants to see it but because it will need time to initialise
4143 * itself before it sees an actual packet. In subsequent key
4144 * exchange phases, we don't pass SSH2_MSG_NEWKEYS on, because
4145 * it would only confuse the layer above.
4146 */
4147 if (!s->first_kex) {
4148 crReturn(0);
4149 }
4150 s->first_kex = 0;
4151
4152 /*
4153 * Now we're encrypting. Begin returning 1 to the protocol main
4154 * function so that other things can run on top of the
4155 * transport. If we ever see a KEXINIT, we must go back to the
4156 * start.
4157 */
4158 while (!(ispkt && ssh->pktin.type == SSH2_MSG_KEXINIT)) {
4159 crReturn(1);
4160 }
4161 logevent("Server initiated key re-exchange");
4162 goto begin_key_exchange;
4163
4164 crFinish(1);
4165 }
4166
4167 /*
4168 * Add data to an SSH2 channel output buffer.
4169 */
4170 static void ssh2_add_channel_data(struct ssh_channel *c, char *buf,
4171 int len)
4172 {
4173 bufchain_add(&c->v.v2.outbuffer, buf, len);
4174 }
4175
4176 /*
4177 * Attempt to send data on an SSH2 channel.
4178 */
4179 static int ssh2_try_send(struct ssh_channel *c)
4180 {
4181 Ssh ssh = c->ssh;
4182
4183 while (c->v.v2.remwindow > 0 && bufchain_size(&c->v.v2.outbuffer) > 0) {
4184 int len;
4185 void *data;
4186 bufchain_prefix(&c->v.v2.outbuffer, &data, &len);
4187 if ((unsigned)len > c->v.v2.remwindow)
4188 len = c->v.v2.remwindow;
4189 if ((unsigned)len > c->v.v2.remmaxpkt)
4190 len = c->v.v2.remmaxpkt;
4191 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_DATA);
4192 ssh2_pkt_adduint32(ssh, c->remoteid);
4193 ssh2_pkt_addstring_start(ssh);
4194 ssh2_pkt_addstring_data(ssh, data, len);
4195 ssh2_pkt_send(ssh);
4196 bufchain_consume(&c->v.v2.outbuffer, len);
4197 c->v.v2.remwindow -= len;
4198 }
4199
4200 /*
4201 * After having sent as much data as we can, return the amount
4202 * still buffered.
4203 */
4204 return bufchain_size(&c->v.v2.outbuffer);
4205 }
4206
4207 /*
4208 * Potentially enlarge the window on an SSH2 channel.
4209 */
4210 static void ssh2_set_window(struct ssh_channel *c, unsigned newwin)
4211 {
4212 Ssh ssh = c->ssh;
4213
4214 /*
4215 * Never send WINDOW_ADJUST for a channel that the remote side
4216 * already thinks it's closed; there's no point, since it won't
4217 * be sending any more data anyway.
4218 */
4219 if (c->closes != 0)
4220 return;
4221
4222 if (newwin > c->v.v2.locwindow) {
4223 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST);
4224 ssh2_pkt_adduint32(ssh, c->remoteid);
4225 ssh2_pkt_adduint32(ssh, newwin - c->v.v2.locwindow);
4226 ssh2_pkt_send(ssh);
4227 c->v.v2.locwindow = newwin;
4228 }
4229 }
4230
4231 /*
4232 * Handle the SSH2 userauth and connection layers.
4233 */
4234 static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
4235 {
4236 struct do_ssh2_authconn_state {
4237 enum {
4238 AUTH_INVALID, AUTH_PUBLICKEY_AGENT, AUTH_PUBLICKEY_FILE,
4239 AUTH_PASSWORD,
4240 AUTH_KEYBOARD_INTERACTIVE
4241 } method;
4242 enum {
4243 AUTH_TYPE_NONE,
4244 AUTH_TYPE_PUBLICKEY,
4245 AUTH_TYPE_PUBLICKEY_OFFER_LOUD,
4246 AUTH_TYPE_PUBLICKEY_OFFER_QUIET,
4247 AUTH_TYPE_PASSWORD,
4248 AUTH_TYPE_KEYBOARD_INTERACTIVE,
4249 AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET
4250 } type;
4251 int gotit, need_pw, can_pubkey, can_passwd, can_keyb_inter;
4252 int tried_pubkey_config, tried_agent, tried_keyb_inter;
4253 int kbd_inter_running;
4254 int we_are_in;
4255 int num_prompts, curr_prompt, echo;
4256 char username[100];
4257 int got_username;
4258 char pwprompt[200];
4259 char password[100];
4260 void *publickey_blob;
4261 int publickey_bloblen;
4262 unsigned char request[5], *response, *p;
4263 int responselen;
4264 int keyi, nkeys;
4265 int authed;
4266 char *pkblob, *alg, *commentp;
4267 int pklen, alglen, commentlen;
4268 int siglen, retlen, len;
4269 char *q, *agentreq, *ret;
4270 int try_send;
4271 };
4272 crState(do_ssh2_authconn_state);
4273
4274 crBegin(ssh->do_ssh2_authconn_crstate);
4275
4276 /*
4277 * Request userauth protocol, and await a response to it.
4278 */
4279 ssh2_pkt_init(ssh, SSH2_MSG_SERVICE_REQUEST);
4280 ssh2_pkt_addstring(ssh, "ssh-userauth");
4281 ssh2_pkt_send(ssh);
4282 crWaitUntilV(ispkt);
4283 if (ssh->pktin.type != SSH2_MSG_SERVICE_ACCEPT) {
4284 bombout(("Server refused user authentication protocol"));
4285 crReturnV;
4286 }
4287
4288 /*
4289 * We repeat this whole loop, including the username prompt,
4290 * until we manage a successful authentication. If the user
4291 * types the wrong _password_, they can be sent back to the
4292 * beginning to try another username, if this is configured on.
4293 * (If they specify a username in the config, they are never
4294 * asked, even if they do give a wrong password.)
4295 *
4296 * I think this best serves the needs of
4297 *
4298 * - the people who have no configuration, no keys, and just
4299 * want to try repeated (username,password) pairs until they
4300 * type both correctly
4301 *
4302 * - people who have keys and configuration but occasionally
4303 * need to fall back to passwords
4304 *
4305 * - people with a key held in Pageant, who might not have
4306 * logged in to a particular machine before; so they want to
4307 * type a username, and then _either_ their key will be
4308 * accepted, _or_ they will type a password. If they mistype
4309 * the username they will want to be able to get back and
4310 * retype it!
4311 */
4312 s->username[0] = '\0';
4313 s->got_username = FALSE;
4314 do {
4315 /*
4316 * Get a username.
4317 */
4318 if (s->got_username && !cfg.change_username) {
4319 /*
4320 * We got a username last time round this loop, and
4321 * with change_username turned off we don't try to get
4322 * it again.
4323 */
4324 } else if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
4325 if (ssh_get_line && !ssh_getline_pw_only) {
4326 if (!ssh_get_line("login as: ",
4327 s->username, sizeof(s->username), FALSE)) {
4328 /*
4329 * get_line failed to get a username.
4330 * Terminate.
4331 */
4332 logevent("No username provided. Abandoning session.");
4333 ssh->state = SSH_STATE_CLOSED;
4334 crReturnV;
4335 }
4336 } else {
4337 int ret; /* need not be saved across crReturn */
4338 c_write_str(ssh, "login as: ");
4339 ssh->send_ok = 1;
4340 setup_userpass_input(ssh, s->username, sizeof(s->username), 1);
4341 do {
4342 crWaitUntilV(!ispkt);
4343 ret = process_userpass_input(ssh, in, inlen);
4344 } while (ret == 0);
4345 if (ret < 0)
4346 cleanup_exit(0);
4347 }
4348 c_write_str(ssh, "\r\n");
4349 s->username[strcspn(s->username, "\n\r")] = '\0';
4350 } else {
4351 char stuff[200];
4352 strncpy(s->username, cfg.username, sizeof(s->username));
4353 s->username[sizeof(s->username)-1] = '\0';
4354 if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
4355 sprintf(stuff, "Using username \"%s\".\r\n", s->username);
4356 c_write_str(ssh, stuff);
4357 }
4358 }
4359 s->got_username = TRUE;
4360
4361 /*
4362 * Send an authentication request using method "none": (a)
4363 * just in case it succeeds, and (b) so that we know what
4364 * authentication methods we can usefully try next.
4365 */
4366 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4367
4368 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4369 ssh2_pkt_addstring(ssh, s->username);
4370 ssh2_pkt_addstring(ssh, "ssh-connection");/* service requested */
4371 ssh2_pkt_addstring(ssh, "none"); /* method */
4372 ssh2_pkt_send(ssh);
4373 s->type = AUTH_TYPE_NONE;
4374 s->gotit = FALSE;
4375 s->we_are_in = FALSE;
4376
4377 s->tried_pubkey_config = FALSE;
4378 s->tried_agent = FALSE;
4379 s->tried_keyb_inter = FALSE;
4380 s->kbd_inter_running = FALSE;
4381 /* Load the pub half of cfg.keyfile so we notice if it's in Pageant */
4382 if (*cfg.keyfile) {
4383 int keytype;
4384 logeventf("Reading private key file \"%.150s\"", cfg.keyfile);
4385 keytype = key_type(cfg.keyfile);
4386 if (keytype == SSH_KEYTYPE_SSH2) {
4387 s->publickey_blob =
4388 ssh2_userkey_loadpub(cfg.keyfile, NULL,
4389 &s->publickey_bloblen);
4390 } else {
4391 char msgbuf[256];
4392 logeventf("Unable to use this key file (%s)",
4393 key_type_to_str(keytype));
4394 sprintf(msgbuf, "Unable to use key file \"%.150s\" (%s)\r\n",
4395 cfg.keyfile, key_type_to_str(keytype));
4396 c_write_str(ssh, msgbuf);
4397 s->publickey_blob = NULL;
4398 }
4399 } else
4400 s->publickey_blob = NULL;
4401
4402 while (1) {
4403 /*
4404 * Wait for the result of the last authentication request.
4405 */
4406 if (!s->gotit)
4407 crWaitUntilV(ispkt);
4408 while (ssh->pktin.type == SSH2_MSG_USERAUTH_BANNER) {
4409 char *banner;
4410 int size;
4411 /*
4412 * Don't show the banner if we're operating in
4413 * non-verbose non-interactive mode. (It's probably
4414 * a script, which means nobody will read the
4415 * banner _anyway_, and moreover the printing of
4416 * the banner will screw up processing on the
4417 * output of (say) plink.)
4418 */
4419 if (flags & (FLAG_VERBOSE | FLAG_INTERACTIVE)) {
4420 ssh2_pkt_getstring(ssh, &banner, &size);
4421 if (banner)
4422 c_write_untrusted(ssh, banner, size);
4423 }
4424 crWaitUntilV(ispkt);
4425 }
4426 if (ssh->pktin.type == SSH2_MSG_USERAUTH_SUCCESS) {
4427 logevent("Access granted");
4428 s->we_are_in = TRUE;
4429 break;
4430 }
4431
4432 if (s->kbd_inter_running &&
4433 ssh->pktin.type == SSH2_MSG_USERAUTH_INFO_REQUEST) {
4434 /*
4435 * This is either a further set-of-prompts packet
4436 * in keyboard-interactive authentication, or it's
4437 * the same one and we came back here with `gotit'
4438 * set. In the former case, we must reset the
4439 * curr_prompt variable.
4440 */
4441 if (!s->gotit)
4442 s->curr_prompt = 0;
4443 } else if (ssh->pktin.type != SSH2_MSG_USERAUTH_FAILURE) {
4444 bombout(("Strange packet received during authentication: type %d",
4445 ssh->pktin.type));
4446 crReturnV;
4447 }
4448
4449 s->gotit = FALSE;
4450
4451 /*
4452 * OK, we're now sitting on a USERAUTH_FAILURE message, so
4453 * we can look at the string in it and know what we can
4454 * helpfully try next.
4455 */
4456 if (ssh->pktin.type == SSH2_MSG_USERAUTH_FAILURE) {
4457 char *methods;
4458 int methlen;
4459 ssh2_pkt_getstring(ssh, &methods, &methlen);
4460 s->kbd_inter_running = FALSE;
4461 if (!ssh2_pkt_getbool(ssh)) {
4462 /*
4463 * We have received an unequivocal Access
4464 * Denied. This can translate to a variety of
4465 * messages:
4466 *
4467 * - if we'd just tried "none" authentication,
4468 * it's not worth printing anything at all
4469 *
4470 * - if we'd just tried a public key _offer_,
4471 * the message should be "Server refused our
4472 * key" (or no message at all if the key
4473 * came from Pageant)
4474 *
4475 * - if we'd just tried anything else, the
4476 * message really should be "Access denied".
4477 *
4478 * Additionally, if we'd just tried password
4479 * authentication, we should break out of this
4480 * whole loop so as to go back to the username
4481 * prompt.
4482 */
4483 if (s->type == AUTH_TYPE_NONE) {
4484 /* do nothing */
4485 } else if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD ||
4486 s->type == AUTH_TYPE_PUBLICKEY_OFFER_QUIET) {
4487 if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD)
4488 c_write_str(ssh, "Server refused our key\r\n");
4489 logevent("Server refused public key");
4490 } else if (s->type==AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET) {
4491 /* server declined keyboard-interactive; ignore */
4492 } else {
4493 c_write_str(ssh, "Access denied\r\n");
4494 logevent("Access denied");
4495 if (s->type == AUTH_TYPE_PASSWORD) {
4496 s->we_are_in = FALSE;
4497 break;
4498 }
4499 }
4500 } else {
4501 c_write_str(ssh, "Further authentication required\r\n");
4502 logevent("Further authentication required");
4503 }
4504
4505 s->can_pubkey =
4506 in_commasep_string("publickey", methods, methlen);
4507 s->can_passwd =
4508 in_commasep_string("password", methods, methlen);
4509 s->can_keyb_inter = cfg.try_ki_auth &&
4510 in_commasep_string("keyboard-interactive", methods, methlen);
4511 }
4512
4513 s->method = 0;
4514 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4515
4516 /*
4517 * Most password/passphrase prompts will be
4518 * non-echoing, so we set this to 0 by default.
4519 * Exception is that some keyboard-interactive prompts
4520 * can be echoing, in which case we'll set this to 1.
4521 */
4522 s->echo = 0;
4523
4524 if (!s->method && s->can_pubkey &&
4525 agent_exists() && !s->tried_agent) {
4526 /*
4527 * Attempt public-key authentication using Pageant.
4528 */
4529 void *r;
4530 s->authed = FALSE;
4531
4532 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4533 ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
4534
4535 s->tried_agent = TRUE;
4536
4537 logevent("Pageant is running. Requesting keys.");
4538
4539 /* Request the keys held by the agent. */
4540 PUT_32BIT(s->request, 1);
4541 s->request[4] = SSH2_AGENTC_REQUEST_IDENTITIES;
4542 agent_query(s->request, 5, &r, &s->responselen);
4543 s->response = (unsigned char *) r;
4544 if (s->response && s->responselen >= 5 &&
4545 s->response[4] == SSH2_AGENT_IDENTITIES_ANSWER) {
4546 s->p = s->response + 5;
4547 s->nkeys = GET_32BIT(s->p);
4548 s->p += 4;
4549 {
4550 char buf[64];
4551 sprintf(buf, "Pageant has %d SSH2 keys", s->nkeys);
4552 logevent(buf);
4553 }
4554 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
4555 void *vret;
4556
4557 {
4558 char buf[64];
4559 sprintf(buf, "Trying Pageant key #%d", s->keyi);
4560 logevent(buf);
4561 }
4562 s->pklen = GET_32BIT(s->p);
4563 s->p += 4;
4564 if (s->publickey_blob &&
4565 s->pklen == s->publickey_bloblen &&
4566 !memcmp(s->p, s->publickey_blob,
4567 s->publickey_bloblen)) {
4568 logevent("This key matches configured key file");
4569 s->tried_pubkey_config = 1;
4570 }
4571 s->pkblob = s->p;
4572 s->p += s->pklen;
4573 s->alglen = GET_32BIT(s->pkblob);
4574 s->alg = s->pkblob + 4;
4575 s->commentlen = GET_32BIT(s->p);
4576 s->p += 4;
4577 s->commentp = s->p;
4578 s->p += s->commentlen;
4579 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4580 ssh2_pkt_addstring(ssh, s->username);
4581 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4582 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4583 ssh2_pkt_addbool(ssh, FALSE); /* no signature included */
4584 ssh2_pkt_addstring_start(ssh);
4585 ssh2_pkt_addstring_data(ssh, s->alg, s->alglen);
4586 ssh2_pkt_addstring_start(ssh);
4587 ssh2_pkt_addstring_data(ssh, s->pkblob, s->pklen);
4588 ssh2_pkt_send(ssh);
4589
4590 crWaitUntilV(ispkt);
4591 if (ssh->pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
4592 logevent("Key refused");
4593 continue;
4594 }
4595
4596 if (flags & FLAG_VERBOSE) {
4597 c_write_str(ssh, "Authenticating with "
4598 "public key \"");
4599 c_write(ssh, s->commentp, s->commentlen);
4600 c_write_str(ssh, "\" from agent\r\n");
4601 }
4602
4603 /*
4604 * Server is willing to accept the key.
4605 * Construct a SIGN_REQUEST.
4606 */
4607 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4608 ssh2_pkt_addstring(ssh, s->username);
4609 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4610 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4611 ssh2_pkt_addbool(ssh, TRUE);
4612 ssh2_pkt_addstring_start(ssh);
4613 ssh2_pkt_addstring_data(ssh, s->alg, s->alglen);
4614 ssh2_pkt_addstring_start(ssh);
4615 ssh2_pkt_addstring_data(ssh, s->pkblob, s->pklen);
4616
4617 s->siglen = ssh->pktout.length - 5 + 4 + 20;
4618 s->len = 1; /* message type */
4619 s->len += 4 + s->pklen; /* key blob */
4620 s->len += 4 + s->siglen; /* data to sign */
4621 s->len += 4; /* flags */
4622 s->agentreq = smalloc(4 + s->len);
4623 PUT_32BIT(s->agentreq, s->len);
4624 s->q = s->agentreq + 4;
4625 *s->q++ = SSH2_AGENTC_SIGN_REQUEST;
4626 PUT_32BIT(s->q, s->pklen);
4627 s->q += 4;
4628 memcpy(s->q, s->pkblob, s->pklen);
4629 s->q += s->pklen;
4630 PUT_32BIT(s->q, s->siglen);
4631 s->q += 4;
4632 /* Now the data to be signed... */
4633 PUT_32BIT(s->q, 20);
4634 s->q += 4;
4635 memcpy(s->q, ssh->v2_session_id, 20);
4636 s->q += 20;
4637 memcpy(s->q, ssh->pktout.data + 5,
4638 ssh->pktout.length - 5);
4639 s->q += ssh->pktout.length - 5;
4640 /* And finally the (zero) flags word. */
4641 PUT_32BIT(s->q, 0);
4642 agent_query(s->agentreq, s->len + 4, &vret, &s->retlen);
4643 s->ret = vret;
4644 sfree(s->agentreq);
4645 if (s->ret) {
4646 if (s->ret[4] == SSH2_AGENT_SIGN_RESPONSE) {
4647 logevent("Sending Pageant's response");
4648 ssh2_add_sigblob(ssh, s->pkblob, s->pklen,
4649 s->ret + 9,
4650 GET_32BIT(s->ret + 5));
4651 ssh2_pkt_send(ssh);
4652 s->authed = TRUE;
4653 break;
4654 } else {
4655 logevent
4656 ("Pageant failed to answer challenge");
4657 sfree(s->ret);
4658 }
4659 }
4660 }
4661 if (s->authed)
4662 continue;
4663 }
4664 }
4665
4666 if (!s->method && s->can_pubkey && s->publickey_blob
4667 && !s->tried_pubkey_config) {
4668 unsigned char *pub_blob;
4669 char *algorithm, *comment;
4670 int pub_blob_len;
4671
4672 s->tried_pubkey_config = TRUE;
4673
4674 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4675 ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
4676
4677 /*
4678 * Try the public key supplied in the configuration.
4679 *
4680 * First, offer the public blob to see if the server is
4681 * willing to accept it.
4682 */
4683 pub_blob = ssh2_userkey_loadpub(cfg.keyfile, &algorithm,
4684 &pub_blob_len);
4685 if (pub_blob) {
4686 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4687 ssh2_pkt_addstring(ssh, s->username);
4688 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4689 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4690 ssh2_pkt_addbool(ssh, FALSE); /* no signature included */
4691 ssh2_pkt_addstring(ssh, algorithm);
4692 ssh2_pkt_addstring_start(ssh);
4693 ssh2_pkt_addstring_data(ssh, pub_blob, pub_blob_len);
4694 ssh2_pkt_send(ssh);
4695 logevent("Offered public key"); /* FIXME */
4696
4697 crWaitUntilV(ispkt);
4698 if (ssh->pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
4699 s->gotit = TRUE;
4700 s->type = AUTH_TYPE_PUBLICKEY_OFFER_LOUD;
4701 continue; /* key refused; give up on it */
4702 }
4703
4704 logevent("Offer of public key accepted");
4705 /*
4706 * Actually attempt a serious authentication using
4707 * the key.
4708 */
4709 if (ssh2_userkey_encrypted(cfg.keyfile, &comment)) {
4710 sprintf(s->pwprompt,
4711 "Passphrase for key \"%.100s\": ",
4712 comment);
4713 s->need_pw = TRUE;
4714 } else {
4715 s->need_pw = FALSE;
4716 }
4717 c_write_str(ssh, "Authenticating with public key \"");
4718 c_write_str(ssh, comment);
4719 c_write_str(ssh, "\"\r\n");
4720 s->method = AUTH_PUBLICKEY_FILE;
4721 }
4722 }
4723
4724 if (!s->method && s->can_keyb_inter && !s->tried_keyb_inter) {
4725 s->method = AUTH_KEYBOARD_INTERACTIVE;
4726 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
4727 s->tried_keyb_inter = TRUE;
4728
4729 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4730 ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;
4731
4732 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4733 ssh2_pkt_addstring(ssh, s->username);
4734 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4735 ssh2_pkt_addstring(ssh, "keyboard-interactive"); /* method */
4736 ssh2_pkt_addstring(ssh, ""); /* lang */
4737 ssh2_pkt_addstring(ssh, "");
4738 ssh2_pkt_send(ssh);
4739
4740 crWaitUntilV(ispkt);
4741 if (ssh->pktin.type != SSH2_MSG_USERAUTH_INFO_REQUEST) {
4742 if (ssh->pktin.type == SSH2_MSG_USERAUTH_FAILURE)
4743 s->gotit = TRUE;
4744 logevent("Keyboard-interactive authentication refused");
4745 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET;
4746 continue;
4747 }
4748
4749 s->kbd_inter_running = TRUE;
4750 s->curr_prompt = 0;
4751 }
4752
4753 if (s->kbd_inter_running) {
4754 s->method = AUTH_KEYBOARD_INTERACTIVE;
4755 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
4756 s->tried_keyb_inter = TRUE;
4757
4758 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4759 ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;
4760
4761 if (s->curr_prompt == 0) {
4762 /*
4763 * We've got a fresh USERAUTH_INFO_REQUEST.
4764 * Display header data, and start going through
4765 * the prompts.
4766 */
4767 char *name, *inst, *lang;
4768 int name_len, inst_len, lang_len;
4769
4770 ssh2_pkt_getstring(ssh, &name, &name_len);
4771 ssh2_pkt_getstring(ssh, &inst, &inst_len);
4772 ssh2_pkt_getstring(ssh, &lang, &lang_len);
4773 if (name_len > 0) {
4774 c_write_untrusted(ssh, name, name_len);
4775 c_write_str(ssh, "\r\n");
4776 }
4777 if (inst_len > 0) {
4778 c_write_untrusted(ssh, inst, inst_len);
4779 c_write_str(ssh, "\r\n");
4780 }
4781 s->num_prompts = ssh2_pkt_getuint32(ssh);
4782 }
4783
4784 /*
4785 * If there are prompts remaining in the packet,
4786 * display one and get a response.
4787 */
4788 if (s->curr_prompt < s->num_prompts) {
4789 char *prompt;
4790 int prompt_len;
4791
4792 ssh2_pkt_getstring(ssh, &prompt, &prompt_len);
4793 if (prompt_len > 0) {
4794 strncpy(s->pwprompt, prompt, sizeof(s->pwprompt));
4795 s->pwprompt[prompt_len < sizeof(s->pwprompt) ?
4796 prompt_len : sizeof(s->pwprompt)-1] = '\0';
4797 } else {
4798 strcpy(s->pwprompt,
4799 "<server failed to send prompt>: ");
4800 }
4801 s->echo = ssh2_pkt_getbool(ssh);
4802 s->need_pw = TRUE;
4803 } else
4804 s->need_pw = FALSE;
4805 }
4806
4807 if (!s->method && s->can_passwd) {
4808 s->method = AUTH_PASSWORD;
4809 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4810 ssh->pkt_ctx |= SSH2_PKTCTX_PASSWORD;
4811 sprintf(s->pwprompt, "%.90s@%.90s's password: ", s->username,
4812 ssh->savedhost);
4813 s->need_pw = TRUE;
4814 }
4815
4816 if (s->need_pw) {
4817 if (ssh_get_line) {
4818 if (!ssh_get_line(s->pwprompt, s->password,
4819 sizeof(s->password), TRUE)) {
4820 /*
4821 * get_line failed to get a password (for
4822 * example because one was supplied on the
4823 * command line which has already failed to
4824 * work). Terminate.
4825 */
4826 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
4827 ssh2_pkt_adduint32(ssh,SSH2_DISCONNECT_BY_APPLICATION);
4828 ssh2_pkt_addstring(ssh, "No more passwords available"
4829 " to try");
4830 ssh2_pkt_addstring(ssh, "en"); /* language tag */
4831 ssh2_pkt_send(ssh);
4832 logevent("Unable to authenticate");
4833 connection_fatal("Unable to authenticate");
4834 ssh->state = SSH_STATE_CLOSED;
4835 crReturnV;
4836 }
4837 } else {
4838 int ret; /* need not be saved across crReturn */
4839 c_write_untrusted(ssh, s->pwprompt, strlen(s->pwprompt));
4840 ssh->send_ok = 1;
4841
4842 setup_userpass_input(ssh, s->password,
4843 sizeof(s->password), s->echo);
4844 do {
4845 crWaitUntilV(!ispkt);
4846 ret = process_userpass_input(ssh, in, inlen);
4847 } while (ret == 0);
4848 if (ret < 0)
4849 cleanup_exit(0);
4850 c_write_str(ssh, "\r\n");
4851 }
4852 }
4853
4854 if (s->method == AUTH_PUBLICKEY_FILE) {
4855 /*
4856 * We have our passphrase. Now try the actual authentication.
4857 */
4858 struct ssh2_userkey *key;
4859
4860 key = ssh2_load_userkey(cfg.keyfile, s->password);
4861 if (key == SSH2_WRONG_PASSPHRASE || key == NULL) {
4862 if (key == SSH2_WRONG_PASSPHRASE) {
4863 c_write_str(ssh, "Wrong passphrase\r\n");
4864 s->tried_pubkey_config = FALSE;
4865 } else {
4866 c_write_str(ssh, "Unable to load private key\r\n");
4867 s->tried_pubkey_config = TRUE;
4868 }
4869 /* Send a spurious AUTH_NONE to return to the top. */
4870 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4871 ssh2_pkt_addstring(ssh, s->username);
4872 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4873 ssh2_pkt_addstring(ssh, "none"); /* method */
4874 ssh2_pkt_send(ssh);
4875 s->type = AUTH_TYPE_NONE;
4876 } else {
4877 unsigned char *pkblob, *sigblob, *sigdata;
4878 int pkblob_len, sigblob_len, sigdata_len;
4879
4880 /*
4881 * We have loaded the private key and the server
4882 * has announced that it's willing to accept it.
4883 * Hallelujah. Generate a signature and send it.
4884 */
4885 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4886 ssh2_pkt_addstring(ssh, s->username);
4887 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4888 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4889 ssh2_pkt_addbool(ssh, TRUE);
4890 ssh2_pkt_addstring(ssh, key->alg->name);
4891 pkblob = key->alg->public_blob(key->data, &pkblob_len);
4892 ssh2_pkt_addstring_start(ssh);
4893 ssh2_pkt_addstring_data(ssh, pkblob, pkblob_len);
4894
4895 /*
4896 * The data to be signed is:
4897 *
4898 * string session-id
4899 *
4900 * followed by everything so far placed in the
4901 * outgoing packet.
4902 */
4903 sigdata_len = ssh->pktout.length - 5 + 4 + 20;
4904 sigdata = smalloc(sigdata_len);
4905 PUT_32BIT(sigdata, 20);
4906 memcpy(sigdata + 4, ssh->v2_session_id, 20);
4907 memcpy(sigdata + 24, ssh->pktout.data + 5,
4908 ssh->pktout.length - 5);
4909 sigblob = key->alg->sign(key->data, sigdata,
4910 sigdata_len, &sigblob_len);
4911 ssh2_add_sigblob(ssh, pkblob, pkblob_len,
4912 sigblob, sigblob_len);
4913 sfree(pkblob);
4914 sfree(sigblob);
4915 sfree(sigdata);
4916
4917 ssh2_pkt_send(ssh);
4918 s->type = AUTH_TYPE_PUBLICKEY;
4919 }
4920 } else if (s->method == AUTH_PASSWORD) {
4921 /*
4922 * We send the password packet lumped tightly together with
4923 * an SSH_MSG_IGNORE packet. The IGNORE packet contains a
4924 * string long enough to make the total length of the two
4925 * packets constant. This should ensure that a passive
4926 * listener doing traffic analyis can't work out the length
4927 * of the password.
4928 *
4929 * For this to work, we need an assumption about the
4930 * maximum length of the password packet. I think 256 is
4931 * pretty conservative. Anyone using a password longer than
4932 * that probably doesn't have much to worry about from
4933 * people who find out how long their password is!
4934 */
4935 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4936 ssh2_pkt_addstring(ssh, s->username);
4937 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4938 ssh2_pkt_addstring(ssh, "password");
4939 ssh2_pkt_addbool(ssh, FALSE);
4940 ssh2_pkt_addstring(ssh, s->password);
4941 ssh2_pkt_defer(ssh);
4942 /*
4943 * We'll include a string that's an exact multiple of the
4944 * cipher block size. If the cipher is NULL for some
4945 * reason, we don't do this trick at all because we gain
4946 * nothing by it.
4947 */
4948 if (ssh->cscipher) {
4949 int stringlen, i;
4950
4951 stringlen = (256 - ssh->deferred_len);
4952 stringlen += ssh->cscipher->blksize - 1;
4953 stringlen -= (stringlen % ssh->cscipher->blksize);
4954 if (ssh->cscomp) {
4955 /*
4956 * Temporarily disable actual compression,
4957 * so we can guarantee to get this string
4958 * exactly the length we want it. The
4959 * compression-disabling routine should
4960 * return an integer indicating how many
4961 * bytes we should adjust our string length
4962 * by.
4963 */
4964 stringlen -=
4965 ssh->cscomp->disable_compression(ssh->cs_comp_ctx);
4966 }
4967 ssh2_pkt_init(ssh, SSH2_MSG_IGNORE);
4968 ssh2_pkt_addstring_start(ssh);
4969 for (i = 0; i < stringlen; i++) {
4970 char c = (char) random_byte();
4971 ssh2_pkt_addstring_data(ssh, &c, 1);
4972 }
4973 ssh2_pkt_defer(ssh);
4974 }
4975 ssh_pkt_defersend(ssh);
4976 logevent("Sent password");
4977 s->type = AUTH_TYPE_PASSWORD;
4978 } else if (s->method == AUTH_KEYBOARD_INTERACTIVE) {
4979 if (s->curr_prompt == 0) {
4980 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_INFO_RESPONSE);
4981 ssh2_pkt_adduint32(ssh, s->num_prompts);
4982 }
4983 if (s->need_pw) { /* only add pw if we just got one! */
4984 ssh2_pkt_addstring(ssh, s->password);
4985 memset(s->password, 0, sizeof(s->password));
4986 s->curr_prompt++;
4987 }
4988 if (s->curr_prompt >= s->num_prompts) {
4989 ssh2_pkt_send(ssh);
4990 } else {
4991 /*
4992 * If there are prompts remaining, we set
4993 * `gotit' so that we won't attempt to get
4994 * another packet. Then we go back round the
4995 * loop and will end up retrieving another
4996 * prompt out of the existing packet. Funky or
4997 * what?
4998 */
4999 s->gotit = TRUE;
5000 }
5001 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
5002 } else {
5003 c_write_str(ssh, "No supported authentication methods"
5004 " left to try!\r\n");
5005 logevent("No supported authentications offered."
5006 " Disconnecting");
5007 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5008 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5009 ssh2_pkt_addstring(ssh, "No supported authentication"
5010 " methods available");
5011 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5012 ssh2_pkt_send(ssh);
5013 ssh->state = SSH_STATE_CLOSED;
5014 crReturnV;
5015 }
5016 }
5017 } while (!s->we_are_in);
5018
5019 /*
5020 * Now we're authenticated for the connection protocol. The
5021 * connection protocol will automatically have started at this
5022 * point; there's no need to send SERVICE_REQUEST.
5023 */
5024
5025 /*
5026 * So now create a channel with a session in it.
5027 */
5028 ssh->channels = newtree234(ssh_channelcmp);
5029 ssh->mainchan = smalloc(sizeof(struct ssh_channel));
5030 ssh->mainchan->ssh = ssh;
5031 ssh->mainchan->localid = alloc_channel_id(ssh);
5032 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN);
5033 ssh2_pkt_addstring(ssh, "session");
5034 ssh2_pkt_adduint32(ssh, ssh->mainchan->localid);
5035 ssh->mainchan->v.v2.locwindow = OUR_V2_WINSIZE;
5036 ssh2_pkt_adduint32(ssh, ssh->mainchan->v.v2.locwindow);/* our window size */
5037 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
5038 ssh2_pkt_send(ssh);
5039 crWaitUntilV(ispkt);
5040 if (ssh->pktin.type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
5041 bombout(("Server refused to open a session"));
5042 crReturnV;
5043 /* FIXME: error data comes back in FAILURE packet */
5044 }
5045 if (ssh2_pkt_getuint32(ssh) != ssh->mainchan->localid) {
5046 bombout(("Server's channel confirmation cited wrong channel"));
5047 crReturnV;
5048 }
5049 ssh->mainchan->remoteid = ssh2_pkt_getuint32(ssh);
5050 ssh->mainchan->type = CHAN_MAINSESSION;
5051 ssh->mainchan->closes = 0;
5052 ssh->mainchan->v.v2.remwindow = ssh2_pkt_getuint32(ssh);
5053 ssh->mainchan->v.v2.remmaxpkt = ssh2_pkt_getuint32(ssh);
5054 bufchain_init(&ssh->mainchan->v.v2.outbuffer);
5055 add234(ssh->channels, ssh->mainchan);
5056 logevent("Opened channel for session");
5057
5058 /*
5059 * Potentially enable X11 forwarding.
5060 */
5061 if (cfg.x11_forward) {
5062 char proto[20], data[64];
5063 logevent("Requesting X11 forwarding");
5064 ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
5065 data, sizeof(data));
5066 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5067 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
5068 ssh2_pkt_addstring(ssh, "x11-req");
5069 ssh2_pkt_addbool(ssh, 1); /* want reply */
5070 ssh2_pkt_addbool(ssh, 0); /* many connections */
5071 ssh2_pkt_addstring(ssh, proto);
5072 ssh2_pkt_addstring(ssh, data);
5073 ssh2_pkt_adduint32(ssh, 0); /* screen number */
5074 ssh2_pkt_send(ssh);
5075
5076 do {
5077 crWaitUntilV(ispkt);
5078 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5079 unsigned i = ssh2_pkt_getuint32(ssh);
5080 struct ssh_channel *c;
5081 c = find234(ssh->channels, &i, ssh_channelfind);
5082 if (!c)
5083 continue; /* nonexistent channel */
5084 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5085 }
5086 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5087
5088 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5089 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5090 bombout(("Unexpected response to X11 forwarding request:"
5091 " packet type %d", ssh->pktin.type));
5092 crReturnV;
5093 }
5094 logevent("X11 forwarding refused");
5095 } else {
5096 logevent("X11 forwarding enabled");
5097 ssh->X11_fwd_enabled = TRUE;
5098 }
5099 }
5100
5101 /*
5102 * Enable port forwardings.
5103 */
5104 {
5105 char type;
5106 int n;
5107 int sport,dport,sserv,dserv;
5108 char sports[256], dports[256], host[256];
5109 char buf[1024];
5110 struct servent *se;
5111
5112 ssh->rportfwds = newtree234(ssh_rportcmp_ssh2);
5113 /* Add port forwardings. */
5114 ssh->portfwd_strptr = cfg.portfwd;
5115 while (*ssh->portfwd_strptr) {
5116 type = *ssh->portfwd_strptr++;
5117 n = 0;
5118 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != '\t')
5119 sports[n++] = *ssh->portfwd_strptr++;
5120 sports[n] = 0;
5121 if (*ssh->portfwd_strptr == '\t')
5122 ssh->portfwd_strptr++;
5123 n = 0;
5124 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':')
5125 host[n++] = *ssh->portfwd_strptr++;
5126 host[n] = 0;
5127 if (*ssh->portfwd_strptr == ':')
5128 ssh->portfwd_strptr++;
5129 n = 0;
5130 while (*ssh->portfwd_strptr)
5131 dports[n++] = *ssh->portfwd_strptr++;
5132 dports[n] = 0;
5133 ssh->portfwd_strptr++;
5134 dport = atoi(dports);
5135 dserv = 0;
5136 if (dport == 0) {
5137 dserv = 1;
5138 se = getservbyname(dports, NULL);
5139 if (se != NULL) {
5140 dport = ntohs(se->s_port);
5141 } else {
5142 sprintf(buf,
5143 "Service lookup failed for destination port \"%s\"",
5144 dports);
5145 logevent(buf);
5146 }
5147 }
5148 sport = atoi(sports);
5149 sserv = 0;
5150 if (sport == 0) {
5151 sserv = 1;
5152 se = getservbyname(sports, NULL);
5153 if (se != NULL) {
5154 sport = ntohs(se->s_port);
5155 } else {
5156 sprintf(buf,
5157 "Service lookup failed for source port \"%s\"",
5158 sports);
5159 logevent(buf);
5160 }
5161 }
5162 if (sport && dport) {
5163 if (type == 'L') {
5164 pfd_addforward(host, dport, sport, ssh);
5165 sprintf(buf, "Local port %.*s%.*s%d%.*s forwarding to"
5166 " %s:%.*s%.*s%d%.*s",
5167 sserv ? strlen(sports) : 0, sports,
5168 sserv, "(", sport, sserv, ")",
5169 host,
5170 dserv ? strlen(dports) : 0, dports,
5171 dserv, "(", dport, dserv, ")");
5172 logevent(buf);
5173 } else {
5174 struct ssh_rportfwd *pf;
5175 pf = smalloc(sizeof(*pf));
5176 strcpy(pf->dhost, host);
5177 pf->dport = dport;
5178 pf->sport = sport;
5179 if (add234(ssh->rportfwds, pf) != pf) {
5180 sprintf(buf,
5181 "Duplicate remote port forwarding to %s:%d",
5182 host, dport);
5183 logevent(buf);
5184 sfree(pf);
5185 } else {
5186 sprintf(buf, "Requesting remote port %.*s%.*s%d%.*s"
5187 " forward to %s:%.*s%.*s%d%.*s",
5188 sserv ? strlen(sports) : 0, sports,
5189 sserv, "(", sport, sserv, ")",
5190 host,
5191 dserv ? strlen(dports) : 0, dports,
5192 dserv, "(", dport, dserv, ")");
5193 logevent(buf);
5194 ssh2_pkt_init(ssh, SSH2_MSG_GLOBAL_REQUEST);
5195 ssh2_pkt_addstring(ssh, "tcpip-forward");
5196 ssh2_pkt_addbool(ssh, 1);/* want reply */
5197 if (cfg.rport_acceptall)
5198 ssh2_pkt_addstring(ssh, "0.0.0.0");
5199 else
5200 ssh2_pkt_addstring(ssh, "127.0.0.1");
5201 ssh2_pkt_adduint32(ssh, sport);
5202 ssh2_pkt_send(ssh);
5203
5204 do {
5205 crWaitUntilV(ispkt);
5206 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5207 unsigned i = ssh2_pkt_getuint32(ssh);
5208 struct ssh_channel *c;
5209 c = find234(ssh->channels, &i, ssh_channelfind);
5210 if (!c)
5211 continue;/* nonexistent channel */
5212 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5213 }
5214 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5215
5216 if (ssh->pktin.type != SSH2_MSG_REQUEST_SUCCESS) {
5217 if (ssh->pktin.type != SSH2_MSG_REQUEST_FAILURE) {
5218 bombout(("Unexpected response to port "
5219 "forwarding request: packet type %d",
5220 ssh->pktin.type));
5221 crReturnV;
5222 }
5223 logevent("Server refused this port forwarding");
5224 } else {
5225 logevent("Remote port forwarding enabled");
5226 }
5227 }
5228 }
5229 }
5230 }
5231 }
5232
5233 /*
5234 * Potentially enable agent forwarding.
5235 */
5236 if (cfg.agentfwd && agent_exists()) {
5237 logevent("Requesting OpenSSH-style agent forwarding");
5238 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5239 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
5240 ssh2_pkt_addstring(ssh, "auth-agent-req@openssh.com");
5241 ssh2_pkt_addbool(ssh, 1); /* want reply */
5242 ssh2_pkt_send(ssh);
5243
5244 do {
5245 crWaitUntilV(ispkt);
5246 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5247 unsigned i = ssh2_pkt_getuint32(ssh);
5248 struct ssh_channel *c;
5249 c = find234(ssh->channels, &i, ssh_channelfind);
5250 if (!c)
5251 continue; /* nonexistent channel */
5252 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5253 }
5254 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5255
5256 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5257 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5258 bombout(("Unexpected response to agent forwarding request:"
5259 " packet type %d", ssh->pktin.type));
5260 crReturnV;
5261 }
5262 logevent("Agent forwarding refused");
5263 } else {
5264 logevent("Agent forwarding enabled");
5265 ssh->agentfwd_enabled = TRUE;
5266 }
5267 }
5268
5269 /*
5270 * Now allocate a pty for the session.
5271 */
5272 if (!cfg.nopty) {
5273 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5274 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid); /* recipient channel */
5275 ssh2_pkt_addstring(ssh, "pty-req");
5276 ssh2_pkt_addbool(ssh, 1); /* want reply */
5277 ssh2_pkt_addstring(ssh, cfg.termtype);
5278 ssh2_pkt_adduint32(ssh, ssh->term_width);
5279 ssh2_pkt_adduint32(ssh, ssh->term_height);
5280 ssh2_pkt_adduint32(ssh, 0); /* pixel width */
5281 ssh2_pkt_adduint32(ssh, 0); /* pixel height */
5282 ssh2_pkt_addstring_start(ssh);
5283 ssh2_pkt_addstring_data(ssh, "\0", 1); /* TTY_OP_END, no special options */
5284 ssh2_pkt_send(ssh);
5285 ssh->state = SSH_STATE_INTERMED;
5286
5287 do {
5288 crWaitUntilV(ispkt);
5289 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5290 unsigned i = ssh2_pkt_getuint32(ssh);
5291 struct ssh_channel *c;
5292 c = find234(ssh->channels, &i, ssh_channelfind);
5293 if (!c)
5294 continue; /* nonexistent channel */
5295 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5296 }
5297 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5298
5299 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5300 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5301 bombout(("Unexpected response to pty request:"
5302 " packet type %d", ssh->pktin.type));
5303 crReturnV;
5304 }
5305 c_write_str(ssh, "Server refused to allocate pty\r\n");
5306 ssh->editing = ssh->echoing = 1;
5307 } else {
5308 logevent("Allocated pty");
5309 }
5310 } else {
5311 ssh->editing = ssh->echoing = 1;
5312 }
5313
5314 /*
5315 * Start a shell or a remote command. We may have to attempt
5316 * this twice if the config data has provided a second choice
5317 * of command.
5318 */
5319 while (1) {
5320 int subsys;
5321 char *cmd;
5322
5323 if (ssh->fallback_cmd) {
5324 subsys = cfg.ssh_subsys2;
5325 cmd = cfg.remote_cmd_ptr2;
5326 } else {
5327 subsys = cfg.ssh_subsys;
5328 cmd = cfg.remote_cmd_ptr;
5329 }
5330
5331 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5332 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid); /* recipient channel */
5333 if (subsys) {
5334 ssh2_pkt_addstring(ssh, "subsystem");
5335 ssh2_pkt_addbool(ssh, 1); /* want reply */
5336 ssh2_pkt_addstring(ssh, cmd);
5337 } else if (*cmd) {
5338 ssh2_pkt_addstring(ssh, "exec");
5339 ssh2_pkt_addbool(ssh, 1); /* want reply */
5340 ssh2_pkt_addstring(ssh, cmd);
5341 } else {
5342 ssh2_pkt_addstring(ssh, "shell");
5343 ssh2_pkt_addbool(ssh, 1); /* want reply */
5344 }
5345 ssh2_pkt_send(ssh);
5346 do {
5347 crWaitUntilV(ispkt);
5348 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5349 unsigned i = ssh2_pkt_getuint32(ssh);
5350 struct ssh_channel *c;
5351 c = find234(ssh->channels, &i, ssh_channelfind);
5352 if (!c)
5353 continue; /* nonexistent channel */
5354 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5355 }
5356 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5357 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5358 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5359 bombout(("Unexpected response to shell/command request:"
5360 " packet type %d", ssh->pktin.type));
5361 crReturnV;
5362 }
5363 /*
5364 * We failed to start the command. If this is the
5365 * fallback command, we really are finished; if it's
5366 * not, and if the fallback command exists, try falling
5367 * back to it before complaining.
5368 */
5369 if (!ssh->fallback_cmd && cfg.remote_cmd_ptr2 != NULL) {
5370 logevent("Primary command failed; attempting fallback");
5371 ssh->fallback_cmd = TRUE;
5372 continue;
5373 }
5374 bombout(("Server refused to start a shell/command"));
5375 crReturnV;
5376 } else {
5377 logevent("Started a shell/command");
5378 }
5379 break;
5380 }
5381
5382 ssh->state = SSH_STATE_SESSION;
5383 if (ssh->size_needed)
5384 ssh_size(ssh, ssh->term_width, ssh->term_height);
5385 if (ssh->eof_needed)
5386 ssh_special(ssh, TS_EOF);
5387
5388 /*
5389 * Transfer data!
5390 */
5391 if (ssh->ldisc)
5392 ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */
5393 ssh->send_ok = 1;
5394 while (1) {
5395 crReturnV;
5396 s->try_send = FALSE;
5397 if (ispkt) {
5398 if (ssh->pktin.type == SSH2_MSG_CHANNEL_DATA ||
5399 ssh->pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA) {
5400 char *data;
5401 int length;
5402 unsigned i = ssh2_pkt_getuint32(ssh);
5403 struct ssh_channel *c;
5404 c = find234(ssh->channels, &i, ssh_channelfind);
5405 if (!c)
5406 continue; /* nonexistent channel */
5407 if (ssh->pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
5408 ssh2_pkt_getuint32(ssh) != SSH2_EXTENDED_DATA_STDERR)
5409 continue; /* extended but not stderr */
5410 ssh2_pkt_getstring(ssh, &data, &length);
5411 if (data) {
5412 int bufsize;
5413 c->v.v2.locwindow -= length;
5414 switch (c->type) {
5415 case CHAN_MAINSESSION:
5416 bufsize =
5417 from_backend(ssh->frontend, ssh->pktin.type ==
5418 SSH2_MSG_CHANNEL_EXTENDED_DATA,
5419 data, length);
5420 break;
5421 case CHAN_X11:
5422 bufsize = x11_send(c->u.x11.s, data, length);
5423 break;
5424 case CHAN_SOCKDATA:
5425 bufsize = pfd_send(c->u.pfd.s, data, length);
5426 break;
5427 case CHAN_AGENT:
5428 while (length > 0) {
5429 if (c->u.a.lensofar < 4) {
5430 int l = min(4 - c->u.a.lensofar, length);
5431 memcpy(c->u.a.msglen + c->u.a.lensofar,
5432 data, l);
5433 data += l;
5434 length -= l;
5435 c->u.a.lensofar += l;
5436 }
5437 if (c->u.a.lensofar == 4) {
5438 c->u.a.totallen =
5439 4 + GET_32BIT(c->u.a.msglen);
5440 c->u.a.message = smalloc(c->u.a.totallen);
5441 memcpy(c->u.a.message, c->u.a.msglen, 4);
5442 }
5443 if (c->u.a.lensofar >= 4 && length > 0) {
5444 int l =
5445 min(c->u.a.totallen - c->u.a.lensofar,
5446 length);
5447 memcpy(c->u.a.message + c->u.a.lensofar,
5448 data, l);
5449 data += l;
5450 length -= l;
5451 c->u.a.lensofar += l;
5452 }
5453 if (c->u.a.lensofar == c->u.a.totallen) {
5454 void *reply, *sentreply;
5455 int replylen;
5456 agent_query(c->u.a.message,
5457 c->u.a.totallen, &reply,
5458 &replylen);
5459 if (reply)
5460 sentreply = reply;
5461 else {
5462 /* Fake SSH_AGENT_FAILURE. */
5463 sentreply = "\0\0\0\1\5";
5464 replylen = 5;
5465 }
5466 ssh2_add_channel_data(c, sentreply, replylen);
5467 s->try_send = TRUE;
5468 if (reply)
5469 sfree(reply);
5470 sfree(c->u.a.message);
5471 c->u.a.lensofar = 0;
5472 }
5473 }
5474 bufsize = 0;
5475 break;
5476 }
5477 /*
5478 * If we are not buffering too much data,
5479 * enlarge the window again at the remote side.
5480 */
5481 if (bufsize < OUR_V2_WINSIZE)
5482 ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
5483 }
5484 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_EOF) {
5485 unsigned i = ssh2_pkt_getuint32(ssh);
5486 struct ssh_channel *c;
5487
5488 c = find234(ssh->channels, &i, ssh_channelfind);
5489 if (!c)
5490 continue; /* nonexistent channel */
5491
5492 if (c->type == CHAN_X11) {
5493 /*
5494 * Remote EOF on an X11 channel means we should
5495 * wrap up and close the channel ourselves.
5496 */
5497 x11_close(c->u.x11.s);
5498 sshfwd_close(c);
5499 } else if (c->type == CHAN_AGENT) {
5500 sshfwd_close(c);
5501 } else if (c->type == CHAN_SOCKDATA) {
5502 pfd_close(c->u.pfd.s);
5503 sshfwd_close(c);
5504 }
5505 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_CLOSE) {
5506 unsigned i = ssh2_pkt_getuint32(ssh);
5507 struct ssh_channel *c;
5508
5509 c = find234(ssh->channels, &i, ssh_channelfind);
5510 if (!c || ((int)c->remoteid) == -1) {
5511 bombout(("Received CHANNEL_CLOSE for %s channel %d\n",
5512 c ? "half-open" : "nonexistent", i));
5513 }
5514 /* Do pre-close processing on the channel. */
5515 switch (c->type) {
5516 case CHAN_MAINSESSION:
5517 break; /* nothing to see here, move along */
5518 case CHAN_X11:
5519 if (c->u.x11.s != NULL)
5520 x11_close(c->u.x11.s);
5521 sshfwd_close(c);
5522 break;
5523 case CHAN_AGENT:
5524 sshfwd_close(c);
5525 break;
5526 case CHAN_SOCKDATA:
5527 if (c->u.pfd.s != NULL)
5528 pfd_close(c->u.pfd.s);
5529 sshfwd_close(c);
5530 break;
5531 }
5532 if (c->closes == 0) {
5533 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
5534 ssh2_pkt_adduint32(ssh, c->remoteid);
5535 ssh2_pkt_send(ssh);
5536 }
5537 del234(ssh->channels, c);
5538 bufchain_clear(&c->v.v2.outbuffer);
5539 sfree(c);
5540
5541 /*
5542 * See if that was the last channel left open.
5543 */
5544 if (count234(ssh->channels) == 0) {
5545 #if 0
5546 /*
5547 * We used to send SSH_MSG_DISCONNECT here,
5548 * because I'd believed that _every_ conforming
5549 * SSH2 connection had to end with a disconnect
5550 * being sent by at least one side; apparently
5551 * I was wrong and it's perfectly OK to
5552 * unceremoniously slam the connection shut
5553 * when you're done, and indeed OpenSSH feels
5554 * this is more polite than sending a
5555 * DISCONNECT. So now we don't.
5556 */
5557 logevent("All channels closed. Disconnecting");
5558 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5559 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5560 ssh2_pkt_addstring(ssh, "All open channels closed");
5561 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5562 ssh2_pkt_send(ssh);
5563 #endif
5564 ssh->state = SSH_STATE_CLOSED;
5565 crReturnV;
5566 }
5567 continue; /* remote sends close; ignore (FIXME) */
5568 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5569 unsigned i = ssh2_pkt_getuint32(ssh);
5570 struct ssh_channel *c;
5571 c = find234(ssh->channels, &i, ssh_channelfind);
5572 if (!c)
5573 continue; /* nonexistent channel */
5574 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5575 s->try_send = TRUE;
5576 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
5577 unsigned i = ssh2_pkt_getuint32(ssh);
5578 struct ssh_channel *c;
5579 c = find234(ssh->channels, &i, ssh_channelfind);
5580 if (!c)
5581 continue; /* nonexistent channel */
5582 if (c->type != CHAN_SOCKDATA_DORMANT)
5583 continue; /* dunno why they're confirming this */
5584 c->remoteid = ssh2_pkt_getuint32(ssh);
5585 c->type = CHAN_SOCKDATA;
5586 c->v.v2.remwindow = ssh2_pkt_getuint32(ssh);
5587 c->v.v2.remmaxpkt = ssh2_pkt_getuint32(ssh);
5588 if (c->u.pfd.s)
5589 pfd_confirm(c->u.pfd.s);
5590 if (c->closes) {
5591 /*
5592 * We have a pending close on this channel,
5593 * which we decided on before the server acked
5594 * the channel open. So now we know the
5595 * remoteid, we can close it again.
5596 */
5597 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
5598 ssh2_pkt_adduint32(ssh, c->remoteid);
5599 ssh2_pkt_send(ssh);
5600 }
5601 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN_FAILURE) {
5602 unsigned i = ssh2_pkt_getuint32(ssh);
5603 struct ssh_channel *c;
5604 c = find234(ssh->channels, &i, ssh_channelfind);
5605 if (!c)
5606 continue; /* nonexistent channel */
5607 if (c->type != CHAN_SOCKDATA_DORMANT)
5608 continue; /* dunno why they're failing this */
5609
5610 logevent("Forwarded connection refused by server");
5611
5612 pfd_close(c->u.pfd.s);
5613
5614 del234(ssh->channels, c);
5615 sfree(c);
5616 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_REQUEST) {
5617 unsigned localid;
5618 char *type;
5619 int typelen, want_reply;
5620 struct ssh_channel *c;
5621
5622 localid = ssh2_pkt_getuint32(ssh);
5623 ssh2_pkt_getstring(ssh, &type, &typelen);
5624 want_reply = ssh2_pkt_getbool(ssh);
5625
5626 /*
5627 * First, check that the channel exists. Otherwise,
5628 * we can instantly disconnect with a rude message.
5629 */
5630 c = find234(ssh->channels, &localid, ssh_channelfind);
5631 if (!c) {
5632 char buf[80];
5633 sprintf(buf, "Received channel request for nonexistent"
5634 " channel %d", localid);
5635 logevent(buf);
5636 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5637 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5638 ssh2_pkt_addstring(ssh, buf);
5639 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5640 ssh2_pkt_send(ssh);
5641 connection_fatal("%s", buf);
5642 ssh->state = SSH_STATE_CLOSED;
5643 crReturnV;
5644 }
5645
5646 /*
5647 * Having got the channel number, we now look at
5648 * the request type string to see if it's something
5649 * we recognise.
5650 */
5651 if (typelen == 11 && !memcmp(type, "exit-status", 11) &&
5652 c == ssh->mainchan) {
5653 /* We recognise "exit-status" on the primary channel. */
5654 char buf[100];
5655 ssh->exitcode = ssh2_pkt_getuint32(ssh);
5656 sprintf(buf, "Server sent command exit status %d",
5657 ssh->exitcode);
5658 logevent(buf);
5659 if (want_reply) {
5660 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_SUCCESS);
5661 ssh2_pkt_adduint32(ssh, c->remoteid);
5662 ssh2_pkt_send(ssh);
5663 }
5664 } else {
5665 /*
5666 * This is a channel request we don't know
5667 * about, so we now either ignore the request
5668 * or respond with CHANNEL_FAILURE, depending
5669 * on want_reply.
5670 */
5671 if (want_reply) {
5672 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_FAILURE);
5673 ssh2_pkt_adduint32(ssh, c->remoteid);
5674 ssh2_pkt_send(ssh);
5675 }
5676 }
5677 } else if (ssh->pktin.type == SSH2_MSG_GLOBAL_REQUEST) {
5678 char *type;
5679 int typelen, want_reply;
5680
5681 ssh2_pkt_getstring(ssh, &type, &typelen);
5682 want_reply = ssh2_pkt_getbool(ssh);
5683
5684 /*
5685 * We currently don't support any global requests
5686 * at all, so we either ignore the request or
5687 * respond with REQUEST_FAILURE, depending on
5688 * want_reply.
5689 */
5690 if (want_reply) {
5691 ssh2_pkt_init(ssh, SSH2_MSG_REQUEST_FAILURE);
5692 ssh2_pkt_send(ssh);
5693 }
5694 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN) {
5695 char *type;
5696 int typelen;
5697 char *error = NULL;
5698 struct ssh_channel *c;
5699 unsigned remid, winsize, pktsize;
5700 ssh2_pkt_getstring(ssh, &type, &typelen);
5701 c = smalloc(sizeof(struct ssh_channel));
5702 c->ssh = ssh;
5703
5704 remid = ssh2_pkt_getuint32(ssh);
5705 winsize = ssh2_pkt_getuint32(ssh);
5706 pktsize = ssh2_pkt_getuint32(ssh);
5707
5708 if (typelen == 3 && !memcmp(type, "x11", 3)) {
5709 if (!ssh->X11_fwd_enabled)
5710 error = "X11 forwarding is not enabled";
5711 else if (x11_init(&c->u.x11.s, cfg.x11_display, c,
5712 ssh->x11auth) != NULL) {
5713 error = "Unable to open an X11 connection";
5714 } else {
5715 c->type = CHAN_X11;
5716 }
5717 } else if (typelen == 15 &&
5718 !memcmp(type, "forwarded-tcpip", 15)) {
5719 struct ssh_rportfwd pf, *realpf;
5720 char *dummy;
5721 int dummylen;
5722 ssh2_pkt_getstring(ssh, &dummy, &dummylen);/* skip address */
5723 pf.sport = ssh2_pkt_getuint32(ssh);
5724 realpf = find234(ssh->rportfwds, &pf, NULL);
5725 if (realpf == NULL) {
5726 error = "Remote port is not recognised";
5727 } else {
5728 char *e = pfd_newconnect(&c->u.pfd.s, realpf->dhost,
5729 realpf->dport, c);
5730 char buf[1024];
5731 sprintf(buf, "Received remote port open request for %s:%d",
5732 realpf->dhost, realpf->dport);
5733 logevent(buf);
5734 if (e != NULL) {
5735 sprintf(buf, "Port open failed: %s", e);
5736 logevent(buf);
5737 error = "Port open failed";
5738 } else {
5739 logevent("Forwarded port opened successfully");
5740 c->type = CHAN_SOCKDATA;
5741 }
5742 }
5743 } else if (typelen == 22 &&
5744 !memcmp(type, "auth-agent@openssh.com", 3)) {
5745 if (!ssh->agentfwd_enabled)
5746 error = "Agent forwarding is not enabled";
5747 else {
5748 c->type = CHAN_AGENT; /* identify channel type */
5749 c->u.a.lensofar = 0;
5750 }
5751 } else {
5752 error = "Unsupported channel type requested";
5753 }
5754
5755 c->remoteid = remid;
5756 if (error) {
5757 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN_FAILURE);
5758 ssh2_pkt_adduint32(ssh, c->remoteid);
5759 ssh2_pkt_adduint32(ssh, SSH2_OPEN_CONNECT_FAILED);
5760 ssh2_pkt_addstring(ssh, error);
5761 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5762 ssh2_pkt_send(ssh);
5763 sfree(c);
5764 } else {
5765 c->localid = alloc_channel_id(ssh);
5766 c->closes = 0;
5767 c->v.v2.locwindow = OUR_V2_WINSIZE;
5768 c->v.v2.remwindow = winsize;
5769 c->v.v2.remmaxpkt = pktsize;
5770 bufchain_init(&c->v.v2.outbuffer);
5771 add234(ssh->channels, c);
5772 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
5773 ssh2_pkt_adduint32(ssh, c->remoteid);
5774 ssh2_pkt_adduint32(ssh, c->localid);
5775 ssh2_pkt_adduint32(ssh, c->v.v2.locwindow);
5776 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
5777 ssh2_pkt_send(ssh);
5778 }
5779 } else {
5780 bombout(("Strange packet received: type %d", ssh->pktin.type));
5781 crReturnV;
5782 }
5783 } else {
5784 /*
5785 * We have spare data. Add it to the channel buffer.
5786 */
5787 ssh2_add_channel_data(ssh->mainchan, in, inlen);
5788 s->try_send = TRUE;
5789 }
5790 if (s->try_send) {
5791 int i;
5792 struct ssh_channel *c;
5793 /*
5794 * Try to send data on all channels if we can.
5795 */
5796 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
5797 int bufsize = ssh2_try_send(c);
5798 if (bufsize == 0) {
5799 switch (c->type) {
5800 case CHAN_MAINSESSION:
5801 /* stdin need not receive an unthrottle
5802 * notification since it will be polled */
5803 break;
5804 case CHAN_X11:
5805 x11_unthrottle(c->u.x11.s);
5806 break;
5807 case CHAN_AGENT:
5808 /* agent sockets are request/response and need no
5809 * buffer management */
5810 break;
5811 case CHAN_SOCKDATA:
5812 pfd_unthrottle(c->u.pfd.s);
5813 break;
5814 }
5815 }
5816 }
5817 }
5818 }
5819
5820 crFinishV;
5821 }
5822
5823 /*
5824 * Handle the top-level SSH2 protocol.
5825 */
5826 static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
5827 {
5828 if (do_ssh2_transport(ssh, in, inlen, ispkt) == 0)
5829 return;
5830 do_ssh2_authconn(ssh, in, inlen, ispkt);
5831 }
5832
5833 /*
5834 * Called to set up the connection.
5835 *
5836 * Returns an error message, or NULL on success.
5837 */
5838 static char *ssh_init(void *frontend_handle, void **backend_handle,
5839 char *host, int port, char **realhost, int nodelay)
5840 {
5841 char *p;
5842 Ssh ssh;
5843
5844 ssh = smalloc(sizeof(*ssh));
5845 ssh->s = NULL;
5846 ssh->cipher = NULL;
5847 ssh->v1_cipher_ctx = NULL;
5848 ssh->crcda_ctx = NULL;
5849 ssh->cscipher = NULL;
5850 ssh->cs_cipher_ctx = NULL;
5851 ssh->sccipher = NULL;
5852 ssh->sc_cipher_ctx = NULL;
5853 ssh->csmac = NULL;
5854 ssh->sc_mac_ctx = NULL;
5855 ssh->scmac = NULL;
5856 ssh->sc_mac_ctx = NULL;
5857 ssh->cscomp = NULL;
5858 ssh->cs_comp_ctx = NULL;
5859 ssh->sccomp = NULL;
5860 ssh->sc_comp_ctx = NULL;
5861 ssh->kex = NULL;
5862 ssh->hostkey = NULL;
5863 ssh->exitcode = -1;
5864 ssh->state = SSH_STATE_PREPACKET;
5865 ssh->size_needed = FALSE;
5866 ssh->eof_needed = FALSE;
5867 ssh->ldisc = NULL;
5868 {
5869 static const struct Packet empty = { 0, 0, NULL, NULL, 0 };
5870 ssh->pktin = ssh->pktout = empty;
5871 }
5872 ssh->deferred_send_data = NULL;
5873 ssh->deferred_len = 0;
5874 ssh->deferred_size = 0;
5875 ssh->fallback_cmd = 0;
5876 ssh->pkt_ctx = 0;
5877 ssh->x11auth = NULL;
5878 ssh->v2_outgoing_sequence = 0;
5879 ssh->ssh1_rdpkt_crstate = 0;
5880 ssh->ssh2_rdpkt_crstate = 0;
5881 ssh->do_ssh_init_crstate = 0;
5882 ssh->ssh_gotdata_crstate = 0;
5883 ssh->ssh1_protocol_crstate = 0;
5884 ssh->do_ssh1_login_crstate = 0;
5885 ssh->do_ssh2_transport_crstate = 0;
5886 ssh->do_ssh2_authconn_crstate = 0;
5887 ssh->do_ssh_init_state = NULL;
5888 ssh->do_ssh1_login_state = NULL;
5889 ssh->do_ssh2_transport_state = NULL;
5890 ssh->do_ssh2_authconn_state = NULL;
5891
5892 *backend_handle = ssh;
5893
5894 #ifdef MSCRYPTOAPI
5895 if (crypto_startup() == 0)
5896 return "Microsoft high encryption pack not installed!";
5897 #endif
5898
5899 ssh->frontend = frontend_handle;
5900 ssh->term_width = cfg.width;
5901 ssh->term_height = cfg.height;
5902
5903 ssh->send_ok = 0;
5904 ssh->editing = 0;
5905 ssh->echoing = 0;
5906 ssh->v1_throttle_count = 0;
5907 ssh->overall_bufsize = 0;
5908 ssh->fallback_cmd = 0;
5909
5910 p = connect_to_host(ssh, host, port, realhost, nodelay);
5911 if (p != NULL)
5912 return p;
5913
5914 return NULL;
5915 }
5916
5917 /*
5918 * Called to send data down the Telnet connection.
5919 */
5920 static int ssh_send(void *handle, char *buf, int len)
5921 {
5922 Ssh ssh = (Ssh) handle;
5923
5924 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
5925 return 0;
5926
5927 ssh->protocol(ssh, buf, len, 0);
5928
5929 return ssh_sendbuffer(ssh);
5930 }
5931
5932 /*
5933 * Called to query the current amount of buffered stdin data.
5934 */
5935 static int ssh_sendbuffer(void *handle)
5936 {
5937 Ssh ssh = (Ssh) handle;
5938 int override_value;
5939
5940 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
5941 return 0;
5942
5943 /*
5944 * If the SSH socket itself has backed up, add the total backup
5945 * size on that to any individual buffer on the stdin channel.
5946 */
5947 override_value = 0;
5948 if (ssh->throttled_all)
5949 override_value = ssh->overall_bufsize;
5950
5951 if (ssh->version == 1) {
5952 return override_value;
5953 } else if (ssh->version == 2) {
5954 if (!ssh->mainchan || ssh->mainchan->closes > 0)
5955 return override_value;
5956 else
5957 return (override_value +
5958 bufchain_size(&ssh->mainchan->v.v2.outbuffer));
5959 }
5960
5961 return 0;
5962 }
5963
5964 /*
5965 * Called to set the size of the window from SSH's POV.
5966 */
5967 static void ssh_size(void *handle, int width, int height)
5968 {
5969 Ssh ssh = (Ssh) handle;
5970
5971 ssh->term_width = width;
5972 ssh->term_height = height;
5973
5974 switch (ssh->state) {
5975 case SSH_STATE_BEFORE_SIZE:
5976 case SSH_STATE_PREPACKET:
5977 case SSH_STATE_CLOSED:
5978 break; /* do nothing */
5979 case SSH_STATE_INTERMED:
5980 ssh->size_needed = TRUE; /* buffer for later */
5981 break;
5982 case SSH_STATE_SESSION:
5983 if (!cfg.nopty) {
5984 if (ssh->version == 1) {
5985 send_packet(ssh, SSH1_CMSG_WINDOW_SIZE,
5986 PKT_INT, ssh->term_height,
5987 PKT_INT, ssh->term_width,
5988 PKT_INT, 0, PKT_INT, 0, PKT_END);
5989 } else {
5990 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5991 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
5992 ssh2_pkt_addstring(ssh, "window-change");
5993 ssh2_pkt_addbool(ssh, 0);
5994 ssh2_pkt_adduint32(ssh, ssh->term_width);
5995 ssh2_pkt_adduint32(ssh, ssh->term_height);
5996 ssh2_pkt_adduint32(ssh, 0);
5997 ssh2_pkt_adduint32(ssh, 0);
5998 ssh2_pkt_send(ssh);
5999 }
6000 }
6001 break;
6002 }
6003 }
6004
6005 /*
6006 * Send Telnet special codes. TS_EOF is useful for `plink', so you
6007 * can send an EOF and collect resulting output (e.g. `plink
6008 * hostname sort').
6009 */
6010 static void ssh_special(void *handle, Telnet_Special code)
6011 {
6012 Ssh ssh = (Ssh) handle;
6013
6014 if (code == TS_EOF) {
6015 if (ssh->state != SSH_STATE_SESSION) {
6016 /*
6017 * Buffer the EOF in case we are pre-SESSION, so we can
6018 * send it as soon as we reach SESSION.
6019 */
6020 if (code == TS_EOF)
6021 ssh->eof_needed = TRUE;
6022 return;
6023 }
6024 if (ssh->version == 1) {
6025 send_packet(ssh, SSH1_CMSG_EOF, PKT_END);
6026 } else {
6027 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_EOF);
6028 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
6029 ssh2_pkt_send(ssh);
6030 }
6031 logevent("Sent EOF message");
6032 } else if (code == TS_PING) {
6033 if (ssh->state == SSH_STATE_CLOSED
6034 || ssh->state == SSH_STATE_PREPACKET) return;
6035 if (ssh->version == 1) {
6036 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE))
6037 send_packet(ssh, SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
6038 } else {
6039 ssh2_pkt_init(ssh, SSH2_MSG_IGNORE);
6040 ssh2_pkt_addstring_start(ssh);
6041 ssh2_pkt_send(ssh);
6042 }
6043 } else {
6044 /* do nothing */
6045 }
6046 }
6047
6048 void *new_sock_channel(void *handle, Socket s)
6049 {
6050 Ssh ssh = (Ssh) handle;
6051 struct ssh_channel *c;
6052 c = smalloc(sizeof(struct ssh_channel));
6053 c->ssh = ssh;
6054
6055 if (c) {
6056 c->remoteid = -1; /* to be set when open confirmed */
6057 c->localid = alloc_channel_id(ssh);
6058 c->closes = 0;
6059 c->type = CHAN_SOCKDATA_DORMANT;/* identify channel type */
6060 c->u.pfd.s = s;
6061 bufchain_init(&c->v.v2.outbuffer);
6062 add234(ssh->channels, c);
6063 }
6064 return c;
6065 }
6066
6067 /*
6068 * This is called when stdout/stderr (the entity to which
6069 * from_backend sends data) manages to clear some backlog.
6070 */
6071 void ssh_unthrottle(void *handle, int bufsize)
6072 {
6073 Ssh ssh = (Ssh) handle;
6074 if (ssh->version == 1) {
6075 if (ssh->v1_stdout_throttling && bufsize < SSH1_BUFFER_LIMIT) {
6076 ssh->v1_stdout_throttling = 0;
6077 ssh1_throttle(ssh, -1);
6078 }
6079 } else {
6080 if (ssh->mainchan && ssh->mainchan->closes == 0)
6081 ssh2_set_window(ssh->mainchan, OUR_V2_WINSIZE - bufsize);
6082 }
6083 }
6084
6085 void ssh_send_port_open(void *channel, char *hostname, int port, char *org)
6086 {
6087 struct ssh_channel *c = (struct ssh_channel *)channel;
6088 Ssh ssh = c->ssh;
6089 char buf[1024];
6090
6091 sprintf(buf, "Opening forwarded connection to %.512s:%d", hostname, port);
6092 logevent(buf);
6093
6094 if (ssh->version == 1) {
6095 send_packet(ssh, SSH1_MSG_PORT_OPEN,
6096 PKT_INT, c->localid,
6097 PKT_STR, hostname,
6098 PKT_INT, port,
6099 //PKT_STR, <org:orgport>,
6100 PKT_END);
6101 } else {
6102 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN);
6103 ssh2_pkt_addstring(ssh, "direct-tcpip");
6104 ssh2_pkt_adduint32(ssh, c->localid);
6105 c->v.v2.locwindow = OUR_V2_WINSIZE;
6106 ssh2_pkt_adduint32(ssh, c->v.v2.locwindow);/* our window size */
6107 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
6108 ssh2_pkt_addstring(ssh, hostname);
6109 ssh2_pkt_adduint32(ssh, port);
6110 /*
6111 * We make up values for the originator data; partly it's
6112 * too much hassle to keep track, and partly I'm not
6113 * convinced the server should be told details like that
6114 * about my local network configuration.
6115 */
6116 ssh2_pkt_addstring(ssh, "client-side-connection");
6117 ssh2_pkt_adduint32(ssh, 0);
6118 ssh2_pkt_send(ssh);
6119 }
6120 }
6121
6122
6123 static Socket ssh_socket(void *handle)
6124 {
6125 Ssh ssh = (Ssh) handle;
6126 return ssh->s;
6127 }
6128
6129 static int ssh_sendok(void *handle)
6130 {
6131 Ssh ssh = (Ssh) handle;
6132 return ssh->send_ok;
6133 }
6134
6135 static int ssh_ldisc(void *handle, int option)
6136 {
6137 Ssh ssh = (Ssh) handle;
6138 if (option == LD_ECHO)
6139 return ssh->echoing;
6140 if (option == LD_EDIT)
6141 return ssh->editing;
6142 return FALSE;
6143 }
6144
6145 static void ssh_provide_ldisc(void *handle, void *ldisc)
6146 {
6147 Ssh ssh = (Ssh) handle;
6148 ssh->ldisc = ldisc;
6149 }
6150
6151 static int ssh_return_exitcode(void *handle)
6152 {
6153 Ssh ssh = (Ssh) handle;
6154 return ssh->exitcode;
6155 }
6156
6157 /*
6158 * Gross hack: pscp will try to start SFTP but fall back to scp1 if
6159 * that fails. This variable is the means by which scp.c can reach
6160 * into the SSH code and find out which one it got.
6161 */
6162 extern int ssh_fallback_cmd(void *handle)
6163 {
6164 Ssh ssh = (Ssh) handle;
6165 return ssh->fallback_cmd;
6166 }
6167
6168 Backend ssh_backend = {
6169 ssh_init,
6170 ssh_send,
6171 ssh_sendbuffer,
6172 ssh_size,
6173 ssh_special,
6174 ssh_socket,
6175 ssh_return_exitcode,
6176 ssh_sendok,
6177 ssh_ldisc,
6178 ssh_provide_ldisc,
6179 ssh_unthrottle,
6180 22
6181 };
Local modifications for Simon Tatham's `PuTTY' SSH client and terminal emulator