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442d35a3e6128fd1976b6abdb55d1423f2f167f5
[u/mdw/putty] / ssh.c
1 #include <stdio.h>
2 #include <stdlib.h>
3 #include <stdarg.h>
4 #include <assert.h>
5
6 #include "putty.h"
7 #include "tree234.h"
8 #include "ssh.h"
9
10 #ifndef FALSE
11 #define FALSE 0
12 #endif
13 #ifndef TRUE
14 #define TRUE 1
15 #endif
16
17 #define SSH1_MSG_DISCONNECT 1 /* 0x1 */
18 #define SSH1_SMSG_PUBLIC_KEY 2 /* 0x2 */
19 #define SSH1_CMSG_SESSION_KEY 3 /* 0x3 */
20 #define SSH1_CMSG_USER 4 /* 0x4 */
21 #define SSH1_CMSG_AUTH_RSA 6 /* 0x6 */
22 #define SSH1_SMSG_AUTH_RSA_CHALLENGE 7 /* 0x7 */
23 #define SSH1_CMSG_AUTH_RSA_RESPONSE 8 /* 0x8 */
24 #define SSH1_CMSG_AUTH_PASSWORD 9 /* 0x9 */
25 #define SSH1_CMSG_REQUEST_PTY 10 /* 0xa */
26 #define SSH1_CMSG_WINDOW_SIZE 11 /* 0xb */
27 #define SSH1_CMSG_EXEC_SHELL 12 /* 0xc */
28 #define SSH1_CMSG_EXEC_CMD 13 /* 0xd */
29 #define SSH1_SMSG_SUCCESS 14 /* 0xe */
30 #define SSH1_SMSG_FAILURE 15 /* 0xf */
31 #define SSH1_CMSG_STDIN_DATA 16 /* 0x10 */
32 #define SSH1_SMSG_STDOUT_DATA 17 /* 0x11 */
33 #define SSH1_SMSG_STDERR_DATA 18 /* 0x12 */
34 #define SSH1_CMSG_EOF 19 /* 0x13 */
35 #define SSH1_SMSG_EXIT_STATUS 20 /* 0x14 */
36 #define SSH1_MSG_CHANNEL_OPEN_CONFIRMATION 21 /* 0x15 */
37 #define SSH1_MSG_CHANNEL_OPEN_FAILURE 22 /* 0x16 */
38 #define SSH1_MSG_CHANNEL_DATA 23 /* 0x17 */
39 #define SSH1_MSG_CHANNEL_CLOSE 24 /* 0x18 */
40 #define SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION 25 /* 0x19 */
41 #define SSH1_SMSG_X11_OPEN 27 /* 0x1b */
42 #define SSH1_CMSG_PORT_FORWARD_REQUEST 28 /* 0x1c */
43 #define SSH1_MSG_PORT_OPEN 29 /* 0x1d */
44 #define SSH1_CMSG_AGENT_REQUEST_FORWARDING 30 /* 0x1e */
45 #define SSH1_SMSG_AGENT_OPEN 31 /* 0x1f */
46 #define SSH1_MSG_IGNORE 32 /* 0x20 */
47 #define SSH1_CMSG_EXIT_CONFIRMATION 33 /* 0x21 */
48 #define SSH1_CMSG_X11_REQUEST_FORWARDING 34 /* 0x22 */
49 #define SSH1_CMSG_AUTH_RHOSTS_RSA 35 /* 0x23 */
50 #define SSH1_MSG_DEBUG 36 /* 0x24 */
51 #define SSH1_CMSG_REQUEST_COMPRESSION 37 /* 0x25 */
52 #define SSH1_CMSG_AUTH_TIS 39 /* 0x27 */
53 #define SSH1_SMSG_AUTH_TIS_CHALLENGE 40 /* 0x28 */
54 #define SSH1_CMSG_AUTH_TIS_RESPONSE 41 /* 0x29 */
55 #define SSH1_CMSG_AUTH_CCARD 70 /* 0x46 */
56 #define SSH1_SMSG_AUTH_CCARD_CHALLENGE 71 /* 0x47 */
57 #define SSH1_CMSG_AUTH_CCARD_RESPONSE 72 /* 0x48 */
58
59 #define SSH1_AUTH_TIS 5 /* 0x5 */
60 #define SSH1_AUTH_CCARD 16 /* 0x10 */
61
62 #define SSH1_PROTOFLAG_SCREEN_NUMBER 1 /* 0x1 */
63 /* Mask for protoflags we will echo back to server if seen */
64 #define SSH1_PROTOFLAGS_SUPPORTED 0 /* 0x1 */
65
66 #define SSH2_MSG_DISCONNECT 1 /* 0x1 */
67 #define SSH2_MSG_IGNORE 2 /* 0x2 */
68 #define SSH2_MSG_UNIMPLEMENTED 3 /* 0x3 */
69 #define SSH2_MSG_DEBUG 4 /* 0x4 */
70 #define SSH2_MSG_SERVICE_REQUEST 5 /* 0x5 */
71 #define SSH2_MSG_SERVICE_ACCEPT 6 /* 0x6 */
72 #define SSH2_MSG_KEXINIT 20 /* 0x14 */
73 #define SSH2_MSG_NEWKEYS 21 /* 0x15 */
74 #define SSH2_MSG_KEXDH_INIT 30 /* 0x1e */
75 #define SSH2_MSG_KEXDH_REPLY 31 /* 0x1f */
76 #define SSH2_MSG_KEX_DH_GEX_REQUEST 30 /* 0x1e */
77 #define SSH2_MSG_KEX_DH_GEX_GROUP 31 /* 0x1f */
78 #define SSH2_MSG_KEX_DH_GEX_INIT 32 /* 0x20 */
79 #define SSH2_MSG_KEX_DH_GEX_REPLY 33 /* 0x21 */
80 #define SSH2_MSG_USERAUTH_REQUEST 50 /* 0x32 */
81 #define SSH2_MSG_USERAUTH_FAILURE 51 /* 0x33 */
82 #define SSH2_MSG_USERAUTH_SUCCESS 52 /* 0x34 */
83 #define SSH2_MSG_USERAUTH_BANNER 53 /* 0x35 */
84 #define SSH2_MSG_USERAUTH_PK_OK 60 /* 0x3c */
85 #define SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ 60 /* 0x3c */
86 #define SSH2_MSG_USERAUTH_INFO_REQUEST 60 /* 0x3c */
87 #define SSH2_MSG_USERAUTH_INFO_RESPONSE 61 /* 0x3d */
88 #define SSH2_MSG_GLOBAL_REQUEST 80 /* 0x50 */
89 #define SSH2_MSG_REQUEST_SUCCESS 81 /* 0x51 */
90 #define SSH2_MSG_REQUEST_FAILURE 82 /* 0x52 */
91 #define SSH2_MSG_CHANNEL_OPEN 90 /* 0x5a */
92 #define SSH2_MSG_CHANNEL_OPEN_CONFIRMATION 91 /* 0x5b */
93 #define SSH2_MSG_CHANNEL_OPEN_FAILURE 92 /* 0x5c */
94 #define SSH2_MSG_CHANNEL_WINDOW_ADJUST 93 /* 0x5d */
95 #define SSH2_MSG_CHANNEL_DATA 94 /* 0x5e */
96 #define SSH2_MSG_CHANNEL_EXTENDED_DATA 95 /* 0x5f */
97 #define SSH2_MSG_CHANNEL_EOF 96 /* 0x60 */
98 #define SSH2_MSG_CHANNEL_CLOSE 97 /* 0x61 */
99 #define SSH2_MSG_CHANNEL_REQUEST 98 /* 0x62 */
100 #define SSH2_MSG_CHANNEL_SUCCESS 99 /* 0x63 */
101 #define SSH2_MSG_CHANNEL_FAILURE 100 /* 0x64 */
102
103 /*
104 * Packet type contexts, so that ssh2_pkt_type can correctly decode
105 * the ambiguous type numbers back into the correct type strings.
106 */
107 #define SSH2_PKTCTX_DHGROUP1 0x0001
108 #define SSH2_PKTCTX_DHGEX 0x0002
109 #define SSH2_PKTCTX_PUBLICKEY 0x0010
110 #define SSH2_PKTCTX_PASSWORD 0x0020
111 #define SSH2_PKTCTX_KBDINTER 0x0040
112 #define SSH2_PKTCTX_AUTH_MASK 0x00F0
113
114 #define SSH2_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT 1 /* 0x1 */
115 #define SSH2_DISCONNECT_PROTOCOL_ERROR 2 /* 0x2 */
116 #define SSH2_DISCONNECT_KEY_EXCHANGE_FAILED 3 /* 0x3 */
117 #define SSH2_DISCONNECT_HOST_AUTHENTICATION_FAILED 4 /* 0x4 */
118 #define SSH2_DISCONNECT_MAC_ERROR 5 /* 0x5 */
119 #define SSH2_DISCONNECT_COMPRESSION_ERROR 6 /* 0x6 */
120 #define SSH2_DISCONNECT_SERVICE_NOT_AVAILABLE 7 /* 0x7 */
121 #define SSH2_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED 8 /* 0x8 */
122 #define SSH2_DISCONNECT_HOST_KEY_NOT_VERIFIABLE 9 /* 0x9 */
123 #define SSH2_DISCONNECT_CONNECTION_LOST 10 /* 0xa */
124 #define SSH2_DISCONNECT_BY_APPLICATION 11 /* 0xb */
125 #define SSH2_DISCONNECT_TOO_MANY_CONNECTIONS 12 /* 0xc */
126 #define SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER 13 /* 0xd */
127 #define SSH2_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE 14 /* 0xe */
128 #define SSH2_DISCONNECT_ILLEGAL_USER_NAME 15 /* 0xf */
129
130 static const char *const ssh2_disconnect_reasons[] = {
131 NULL,
132 "SSH_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT",
133 "SSH_DISCONNECT_PROTOCOL_ERROR",
134 "SSH_DISCONNECT_KEY_EXCHANGE_FAILED",
135 "SSH_DISCONNECT_HOST_AUTHENTICATION_FAILED",
136 "SSH_DISCONNECT_MAC_ERROR",
137 "SSH_DISCONNECT_COMPRESSION_ERROR",
138 "SSH_DISCONNECT_SERVICE_NOT_AVAILABLE",
139 "SSH_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED",
140 "SSH_DISCONNECT_HOST_KEY_NOT_VERIFIABLE",
141 "SSH_DISCONNECT_CONNECTION_LOST",
142 "SSH_DISCONNECT_BY_APPLICATION",
143 "SSH_DISCONNECT_TOO_MANY_CONNECTIONS",
144 "SSH_DISCONNECT_AUTH_CANCELLED_BY_USER",
145 "SSH_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE",
146 "SSH_DISCONNECT_ILLEGAL_USER_NAME",
147 };
148
149 #define SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED 1 /* 0x1 */
150 #define SSH2_OPEN_CONNECT_FAILED 2 /* 0x2 */
151 #define SSH2_OPEN_UNKNOWN_CHANNEL_TYPE 3 /* 0x3 */
152 #define SSH2_OPEN_RESOURCE_SHORTAGE 4 /* 0x4 */
153
154 #define SSH2_EXTENDED_DATA_STDERR 1 /* 0x1 */
155
156 /*
157 * Various remote-bug flags.
158 */
159 #define BUG_CHOKES_ON_SSH1_IGNORE 1
160 #define BUG_SSH2_HMAC 2
161 #define BUG_NEEDS_SSH1_PLAIN_PASSWORD 4
162 #define BUG_CHOKES_ON_RSA 8
163 #define BUG_SSH2_RSA_PADDING 16
164 #define BUG_SSH2_DERIVEKEY 32
165 #define BUG_SSH2_DH_GEX 64
166
167 #define translate(x) if (type == x) return #x
168 #define translatec(x,ctx) if (type == x && (pkt_ctx & ctx)) return #x
169 char *ssh1_pkt_type(int type)
170 {
171 translate(SSH1_MSG_DISCONNECT);
172 translate(SSH1_SMSG_PUBLIC_KEY);
173 translate(SSH1_CMSG_SESSION_KEY);
174 translate(SSH1_CMSG_USER);
175 translate(SSH1_CMSG_AUTH_RSA);
176 translate(SSH1_SMSG_AUTH_RSA_CHALLENGE);
177 translate(SSH1_CMSG_AUTH_RSA_RESPONSE);
178 translate(SSH1_CMSG_AUTH_PASSWORD);
179 translate(SSH1_CMSG_REQUEST_PTY);
180 translate(SSH1_CMSG_WINDOW_SIZE);
181 translate(SSH1_CMSG_EXEC_SHELL);
182 translate(SSH1_CMSG_EXEC_CMD);
183 translate(SSH1_SMSG_SUCCESS);
184 translate(SSH1_SMSG_FAILURE);
185 translate(SSH1_CMSG_STDIN_DATA);
186 translate(SSH1_SMSG_STDOUT_DATA);
187 translate(SSH1_SMSG_STDERR_DATA);
188 translate(SSH1_CMSG_EOF);
189 translate(SSH1_SMSG_EXIT_STATUS);
190 translate(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION);
191 translate(SSH1_MSG_CHANNEL_OPEN_FAILURE);
192 translate(SSH1_MSG_CHANNEL_DATA);
193 translate(SSH1_MSG_CHANNEL_CLOSE);
194 translate(SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION);
195 translate(SSH1_SMSG_X11_OPEN);
196 translate(SSH1_CMSG_PORT_FORWARD_REQUEST);
197 translate(SSH1_MSG_PORT_OPEN);
198 translate(SSH1_CMSG_AGENT_REQUEST_FORWARDING);
199 translate(SSH1_SMSG_AGENT_OPEN);
200 translate(SSH1_MSG_IGNORE);
201 translate(SSH1_CMSG_EXIT_CONFIRMATION);
202 translate(SSH1_CMSG_X11_REQUEST_FORWARDING);
203 translate(SSH1_CMSG_AUTH_RHOSTS_RSA);
204 translate(SSH1_MSG_DEBUG);
205 translate(SSH1_CMSG_REQUEST_COMPRESSION);
206 translate(SSH1_CMSG_AUTH_TIS);
207 translate(SSH1_SMSG_AUTH_TIS_CHALLENGE);
208 translate(SSH1_CMSG_AUTH_TIS_RESPONSE);
209 translate(SSH1_CMSG_AUTH_CCARD);
210 translate(SSH1_SMSG_AUTH_CCARD_CHALLENGE);
211 translate(SSH1_CMSG_AUTH_CCARD_RESPONSE);
212 return "unknown";
213 }
214 char *ssh2_pkt_type(int pkt_ctx, int type)
215 {
216 translate(SSH2_MSG_DISCONNECT);
217 translate(SSH2_MSG_IGNORE);
218 translate(SSH2_MSG_UNIMPLEMENTED);
219 translate(SSH2_MSG_DEBUG);
220 translate(SSH2_MSG_SERVICE_REQUEST);
221 translate(SSH2_MSG_SERVICE_ACCEPT);
222 translate(SSH2_MSG_KEXINIT);
223 translate(SSH2_MSG_NEWKEYS);
224 translatec(SSH2_MSG_KEXDH_INIT, SSH2_PKTCTX_DHGROUP1);
225 translatec(SSH2_MSG_KEXDH_REPLY, SSH2_PKTCTX_DHGROUP1);
226 translatec(SSH2_MSG_KEX_DH_GEX_REQUEST, SSH2_PKTCTX_DHGEX);
227 translatec(SSH2_MSG_KEX_DH_GEX_GROUP, SSH2_PKTCTX_DHGEX);
228 translatec(SSH2_MSG_KEX_DH_GEX_INIT, SSH2_PKTCTX_DHGEX);
229 translatec(SSH2_MSG_KEX_DH_GEX_REPLY, SSH2_PKTCTX_DHGEX);
230 translate(SSH2_MSG_USERAUTH_REQUEST);
231 translate(SSH2_MSG_USERAUTH_FAILURE);
232 translate(SSH2_MSG_USERAUTH_SUCCESS);
233 translate(SSH2_MSG_USERAUTH_BANNER);
234 translatec(SSH2_MSG_USERAUTH_PK_OK, SSH2_PKTCTX_PUBLICKEY);
235 translatec(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, SSH2_PKTCTX_PASSWORD);
236 translatec(SSH2_MSG_USERAUTH_INFO_REQUEST, SSH2_PKTCTX_KBDINTER);
237 translatec(SSH2_MSG_USERAUTH_INFO_RESPONSE, SSH2_PKTCTX_KBDINTER);
238 translate(SSH2_MSG_GLOBAL_REQUEST);
239 translate(SSH2_MSG_REQUEST_SUCCESS);
240 translate(SSH2_MSG_REQUEST_FAILURE);
241 translate(SSH2_MSG_CHANNEL_OPEN);
242 translate(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
243 translate(SSH2_MSG_CHANNEL_OPEN_FAILURE);
244 translate(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
245 translate(SSH2_MSG_CHANNEL_DATA);
246 translate(SSH2_MSG_CHANNEL_EXTENDED_DATA);
247 translate(SSH2_MSG_CHANNEL_EOF);
248 translate(SSH2_MSG_CHANNEL_CLOSE);
249 translate(SSH2_MSG_CHANNEL_REQUEST);
250 translate(SSH2_MSG_CHANNEL_SUCCESS);
251 translate(SSH2_MSG_CHANNEL_FAILURE);
252 return "unknown";
253 }
254 #undef translate
255 #undef translatec
256
257 #define GET_32BIT(cp) \
258 (((unsigned long)(unsigned char)(cp)[0] << 24) | \
259 ((unsigned long)(unsigned char)(cp)[1] << 16) | \
260 ((unsigned long)(unsigned char)(cp)[2] << 8) | \
261 ((unsigned long)(unsigned char)(cp)[3]))
262
263 #define PUT_32BIT(cp, value) { \
264 (cp)[0] = (unsigned char)((value) >> 24); \
265 (cp)[1] = (unsigned char)((value) >> 16); \
266 (cp)[2] = (unsigned char)((value) >> 8); \
267 (cp)[3] = (unsigned char)(value); }
268
269 enum { PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR, PKT_BIGNUM };
270
271 /* Coroutine mechanics for the sillier bits of the code */
272 #define crBegin(v) { int *crLine = &v; switch(v) { case 0:;
273 #define crState(t) \
274 struct t *s; \
275 if (!ssh->t) ssh->t = smalloc(sizeof(struct t)); \
276 s = ssh->t;
277 #define crFinish(z) } *crLine = 0; return (z); }
278 #define crFinishV } *crLine = 0; return; }
279 #define crReturn(z) \
280 do {\
281 *crLine =__LINE__; return (z); case __LINE__:;\
282 } while (0)
283 #define crReturnV \
284 do {\
285 *crLine=__LINE__; return; case __LINE__:;\
286 } while (0)
287 #define crStop(z) do{ *crLine = 0; return (z); }while(0)
288 #define crStopV do{ *crLine = 0; return; }while(0)
289 #define crWaitUntil(c) do { crReturn(0); } while (!(c))
290 #define crWaitUntilV(c) do { crReturnV; } while (!(c))
291
292 typedef struct ssh_tag *Ssh;
293
294 extern char *x11_init(Socket *, char *, void *, void *);
295 extern void x11_close(Socket);
296 extern int x11_send(Socket, char *, int);
297 extern void *x11_invent_auth(char *, int, char *, int);
298 extern void x11_unthrottle(Socket s);
299 extern void x11_override_throttle(Socket s, int enable);
300 extern int x11_get_screen_number(char *display);
301
302 extern char *pfd_newconnect(Socket * s, char *hostname, int port, void *c);
303 extern char *pfd_addforward(char *desthost, int destport, char *srcaddr,
304 int port, void *backhandle);
305 extern void pfd_close(Socket s);
306 extern int pfd_send(Socket s, char *data, int len);
307 extern void pfd_confirm(Socket s);
308 extern void pfd_unthrottle(Socket s);
309 extern void pfd_override_throttle(Socket s, int enable);
310
311 static void ssh2_pkt_init(Ssh, int pkt_type);
312 static void ssh2_pkt_addbool(Ssh, unsigned char value);
313 static void ssh2_pkt_adduint32(Ssh, unsigned long value);
314 static void ssh2_pkt_addstring_start(Ssh);
315 static void ssh2_pkt_addstring_str(Ssh, char *data);
316 static void ssh2_pkt_addstring_data(Ssh, char *data, int len);
317 static void ssh2_pkt_addstring(Ssh, char *data);
318 static unsigned char *ssh2_mpint_fmt(Bignum b, int *len);
319 static void ssh2_pkt_addmp(Ssh, Bignum b);
320 static int ssh2_pkt_construct(Ssh);
321 static void ssh2_pkt_send(Ssh);
322
323 /*
324 * Buffer management constants. There are several of these for
325 * various different purposes:
326 *
327 * - SSH1_BUFFER_LIMIT is the amount of backlog that must build up
328 * on a local data stream before we throttle the whole SSH
329 * connection (in SSH1 only). Throttling the whole connection is
330 * pretty drastic so we set this high in the hope it won't
331 * happen very often.
332 *
333 * - SSH_MAX_BACKLOG is the amount of backlog that must build up
334 * on the SSH connection itself before we defensively throttle
335 * _all_ local data streams. This is pretty drastic too (though
336 * thankfully unlikely in SSH2 since the window mechanism should
337 * ensure that the server never has any need to throttle its end
338 * of the connection), so we set this high as well.
339 *
340 * - OUR_V2_WINSIZE is the maximum window size we present on SSH2
341 * channels.
342 */
343
344 #define SSH1_BUFFER_LIMIT 32768
345 #define SSH_MAX_BACKLOG 32768
346 #define OUR_V2_WINSIZE 16384
347
348 const static struct ssh_kex *kex_algs[] = {
349 &ssh_diffiehellman_gex,
350 &ssh_diffiehellman
351 };
352
353 const static struct ssh_signkey *hostkey_algs[] = { &ssh_rsa, &ssh_dss };
354
355 static void *nullmac_make_context(void)
356 {
357 return NULL;
358 }
359 static void nullmac_free_context(void *handle)
360 {
361 }
362 static void nullmac_key(void *handle, unsigned char *key)
363 {
364 }
365 static void nullmac_generate(void *handle, unsigned char *blk, int len,
366 unsigned long seq)
367 {
368 }
369 static int nullmac_verify(void *handle, unsigned char *blk, int len,
370 unsigned long seq)
371 {
372 return 1;
373 }
374 const static struct ssh_mac ssh_mac_none = {
375 nullmac_make_context, nullmac_free_context, nullmac_key,
376 nullmac_generate, nullmac_verify, "none", 0
377 };
378 const static struct ssh_mac *macs[] = {
379 &ssh_sha1, &ssh_md5, &ssh_mac_none
380 };
381 const static struct ssh_mac *buggymacs[] = {
382 &ssh_sha1_buggy, &ssh_md5, &ssh_mac_none
383 };
384
385 static void *ssh_comp_none_init(void)
386 {
387 return NULL;
388 }
389 static void ssh_comp_none_cleanup(void *handle)
390 {
391 }
392 static int ssh_comp_none_block(void *handle, unsigned char *block, int len,
393 unsigned char **outblock, int *outlen)
394 {
395 return 0;
396 }
397 static int ssh_comp_none_disable(void *handle)
398 {
399 return 0;
400 }
401 const static struct ssh_compress ssh_comp_none = {
402 "none",
403 ssh_comp_none_init, ssh_comp_none_cleanup, ssh_comp_none_block,
404 ssh_comp_none_init, ssh_comp_none_cleanup, ssh_comp_none_block,
405 ssh_comp_none_disable, NULL
406 };
407 extern const struct ssh_compress ssh_zlib;
408 const static struct ssh_compress *compressions[] = {
409 &ssh_zlib, &ssh_comp_none
410 };
411
412 enum { /* channel types */
413 CHAN_MAINSESSION,
414 CHAN_X11,
415 CHAN_AGENT,
416 CHAN_SOCKDATA,
417 CHAN_SOCKDATA_DORMANT /* one the remote hasn't confirmed */
418 };
419
420 /*
421 * 2-3-4 tree storing channels.
422 */
423 struct ssh_channel {
424 Ssh ssh; /* pointer back to main context */
425 unsigned remoteid, localid;
426 int type;
427 /*
428 * In SSH1, this value contains four bits:
429 *
430 * 1 We have sent SSH1_MSG_CHANNEL_CLOSE.
431 * 2 We have sent SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION.
432 * 4 We have received SSH1_MSG_CHANNEL_CLOSE.
433 * 8 We have received SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION.
434 *
435 * A channel is completely finished with when all four bits are set.
436 */
437 int closes;
438 union {
439 struct ssh1_data_channel {
440 int throttling;
441 } v1;
442 struct ssh2_data_channel {
443 bufchain outbuffer;
444 unsigned remwindow, remmaxpkt;
445 unsigned locwindow;
446 } v2;
447 } v;
448 union {
449 struct ssh_agent_channel {
450 unsigned char *message;
451 unsigned char msglen[4];
452 int lensofar, totallen;
453 } a;
454 struct ssh_x11_channel {
455 Socket s;
456 } x11;
457 struct ssh_pfd_channel {
458 Socket s;
459 } pfd;
460 } u;
461 };
462
463 /*
464 * 2-3-4 tree storing remote->local port forwardings. SSH 1 and SSH
465 * 2 use this structure in different ways, reflecting SSH 2's
466 * altogether saner approach to port forwarding.
467 *
468 * In SSH 1, you arrange a remote forwarding by sending the server
469 * the remote port number, and the local destination host:port.
470 * When a connection comes in, the server sends you back that
471 * host:port pair, and you connect to it. This is a ready-made
472 * security hole if you're not on the ball: a malicious server
473 * could send you back _any_ host:port pair, so if you trustingly
474 * connect to the address it gives you then you've just opened the
475 * entire inside of your corporate network just by connecting
476 * through it to a dodgy SSH server. Hence, we must store a list of
477 * host:port pairs we _are_ trying to forward to, and reject a
478 * connection request from the server if it's not in the list.
479 *
480 * In SSH 2, each side of the connection minds its own business and
481 * doesn't send unnecessary information to the other. You arrange a
482 * remote forwarding by sending the server just the remote port
483 * number. When a connection comes in, the server tells you which
484 * of its ports was connected to; and _you_ have to remember what
485 * local host:port pair went with that port number.
486 *
487 * Hence: in SSH 1 this structure stores host:port pairs we intend
488 * to allow connections to, and is indexed by those host:port
489 * pairs. In SSH 2 it stores a mapping from source port to
490 * destination host:port pair, and is indexed by source port.
491 */
492 struct ssh_rportfwd {
493 unsigned sport, dport;
494 char dhost[256];
495 };
496
497 struct Packet {
498 long length;
499 int type;
500 unsigned char *data;
501 unsigned char *body;
502 long savedpos;
503 long maxlen;
504 };
505
506 static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt);
507 static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt);
508 static void ssh_size(void *handle, int width, int height);
509 static void ssh_special(void *handle, Telnet_Special);
510 static int ssh2_try_send(struct ssh_channel *c);
511 static void ssh2_add_channel_data(struct ssh_channel *c, char *buf, int len);
512 static void ssh_throttle_all(Ssh ssh, int enable, int bufsize);
513 static void ssh2_set_window(struct ssh_channel *c, unsigned newwin);
514 static int ssh_sendbuffer(void *handle);
515
516 struct rdpkt1_state_tag {
517 long len, pad, biglen, to_read;
518 unsigned long realcrc, gotcrc;
519 unsigned char *p;
520 int i;
521 int chunk;
522 };
523
524 struct rdpkt2_state_tag {
525 long len, pad, payload, packetlen, maclen;
526 int i;
527 int cipherblk;
528 unsigned long incoming_sequence;
529 };
530
531 struct ssh_tag {
532 const struct plug_function_table *fn;
533 /* the above field _must_ be first in the structure */
534
535 SHA_State exhash, exhashbase;
536
537 Socket s;
538
539 void *ldisc;
540 void *logctx;
541
542 unsigned char session_key[32];
543 int v1_compressing;
544 int v1_remote_protoflags;
545 int v1_local_protoflags;
546 int agentfwd_enabled;
547 int X11_fwd_enabled;
548 int remote_bugs;
549 const struct ssh_cipher *cipher;
550 void *v1_cipher_ctx;
551 void *crcda_ctx;
552 const struct ssh2_cipher *cscipher, *sccipher;
553 void *cs_cipher_ctx, *sc_cipher_ctx;
554 const struct ssh_mac *csmac, *scmac;
555 void *cs_mac_ctx, *sc_mac_ctx;
556 const struct ssh_compress *cscomp, *sccomp;
557 void *cs_comp_ctx, *sc_comp_ctx;
558 const struct ssh_kex *kex;
559 const struct ssh_signkey *hostkey;
560 unsigned char v2_session_id[20];
561 void *kex_ctx;
562
563 char *savedhost;
564 int savedport;
565 int send_ok;
566 int echoing, editing;
567
568 void *frontend;
569
570 int term_width, term_height;
571
572 tree234 *channels; /* indexed by local id */
573 struct ssh_channel *mainchan; /* primary session channel */
574 int exitcode;
575
576 tree234 *rportfwds;
577
578 enum {
579 SSH_STATE_PREPACKET,
580 SSH_STATE_BEFORE_SIZE,
581 SSH_STATE_INTERMED,
582 SSH_STATE_SESSION,
583 SSH_STATE_CLOSED
584 } state;
585
586 int size_needed, eof_needed;
587
588 struct Packet pktin;
589 struct Packet pktout;
590 unsigned char *deferred_send_data;
591 int deferred_len, deferred_size;
592
593 /*
594 * Gross hack: pscp will try to start SFTP but fall back to
595 * scp1 if that fails. This variable is the means by which
596 * scp.c can reach into the SSH code and find out which one it
597 * got.
598 */
599 int fallback_cmd;
600
601 /*
602 * Used for username and password input.
603 */
604 char *userpass_input_buffer;
605 int userpass_input_buflen;
606 int userpass_input_bufpos;
607 int userpass_input_echo;
608
609 char *portfwd_strptr;
610 int pkt_ctx;
611
612 void *x11auth;
613
614 int version;
615 int v1_throttle_count;
616 int overall_bufsize;
617 int throttled_all;
618 int v1_stdout_throttling;
619 int v2_outgoing_sequence;
620
621 int ssh1_rdpkt_crstate;
622 int ssh2_rdpkt_crstate;
623 int do_ssh_init_crstate;
624 int ssh_gotdata_crstate;
625 int ssh1_protocol_crstate;
626 int do_ssh1_login_crstate;
627 int do_ssh2_transport_crstate;
628 int do_ssh2_authconn_crstate;
629
630 void *do_ssh_init_state;
631 void *do_ssh1_login_state;
632 void *do_ssh2_transport_state;
633 void *do_ssh2_authconn_state;
634
635 struct rdpkt1_state_tag rdpkt1_state;
636 struct rdpkt2_state_tag rdpkt2_state;
637
638 void (*protocol) (Ssh ssh, unsigned char *in, int inlen, int ispkt);
639 int (*s_rdpkt) (Ssh ssh, unsigned char **data, int *datalen);
640 };
641
642 #define logevent(s) logevent(ssh->frontend, s)
643
644 /* logevent, only printf-formatted. */
645 void logeventf(Ssh ssh, char *fmt, ...)
646 {
647 va_list ap;
648 char *buf;
649
650 va_start(ap, fmt);
651 buf = dupvprintf(fmt, ap);
652 va_end(ap);
653 logevent(buf);
654 sfree(buf);
655 }
656
657 #define bombout(msg) ( ssh->state = SSH_STATE_CLOSED, \
658 (ssh->s ? sk_close(ssh->s), ssh->s = NULL : 0), \
659 logeventf msg, connection_fatal msg )
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((ssh,"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((ssh,"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 if (ssh->logctx)
864 log_packet(ssh->logctx,
865 PKT_INCOMING, ssh->pktin.type,
866 ssh1_pkt_type(ssh->pktin.type),
867 ssh->pktin.body, ssh->pktin.length);
868
869 if (ssh->pktin.type == SSH1_SMSG_STDOUT_DATA ||
870 ssh->pktin.type == SSH1_SMSG_STDERR_DATA ||
871 ssh->pktin.type == SSH1_MSG_DEBUG ||
872 ssh->pktin.type == SSH1_SMSG_AUTH_TIS_CHALLENGE ||
873 ssh->pktin.type == SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
874 long stringlen = GET_32BIT(ssh->pktin.body);
875 if (stringlen + 4 != ssh->pktin.length) {
876 bombout((ssh,"Received data packet with bogus string length"));
877 crReturn(0);
878 }
879 }
880
881 if (ssh->pktin.type == SSH1_MSG_DEBUG) {
882 /* log debug message */
883 char buf[512];
884 int stringlen = GET_32BIT(ssh->pktin.body);
885 strcpy(buf, "Remote debug message: ");
886 if (stringlen > 480)
887 stringlen = 480;
888 memcpy(buf + 8, ssh->pktin.body + 4, stringlen);
889 buf[8 + stringlen] = '\0';
890 logevent(buf);
891 goto next_packet;
892 } else if (ssh->pktin.type == SSH1_MSG_IGNORE) {
893 /* do nothing */
894 goto next_packet;
895 }
896
897 if (ssh->pktin.type == SSH1_MSG_DISCONNECT) {
898 /* log reason code in disconnect message */
899 char buf[256];
900 unsigned msglen = GET_32BIT(ssh->pktin.body);
901 unsigned nowlen;
902 strcpy(buf, "Remote sent disconnect: ");
903 nowlen = strlen(buf);
904 if (msglen > sizeof(buf) - nowlen - 1)
905 msglen = sizeof(buf) - nowlen - 1;
906 memcpy(buf + nowlen, ssh->pktin.body + 4, msglen);
907 buf[nowlen + msglen] = '\0';
908 /* logevent(buf); (this is now done within the bombout macro) */
909 bombout((ssh,"Server sent disconnect message:\n\"%s\"", buf+nowlen));
910 crReturn(0);
911 }
912
913 crFinish(0);
914 }
915
916 static int ssh2_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
917 {
918 struct rdpkt2_state_tag *st = &ssh->rdpkt2_state;
919
920 crBegin(ssh->ssh2_rdpkt_crstate);
921
922 next_packet:
923 ssh->pktin.type = 0;
924 ssh->pktin.length = 0;
925 if (ssh->sccipher)
926 st->cipherblk = ssh->sccipher->blksize;
927 else
928 st->cipherblk = 8;
929 if (st->cipherblk < 8)
930 st->cipherblk = 8;
931
932 if (ssh->pktin.maxlen < st->cipherblk) {
933 ssh->pktin.maxlen = st->cipherblk;
934 ssh->pktin.data = srealloc(ssh->pktin.data, st->cipherblk + APIEXTRA);
935 }
936
937 /*
938 * Acquire and decrypt the first block of the packet. This will
939 * contain the length and padding details.
940 */
941 for (st->i = st->len = 0; st->i < st->cipherblk; st->i++) {
942 while ((*datalen) == 0)
943 crReturn(st->cipherblk - st->i);
944 ssh->pktin.data[st->i] = *(*data)++;
945 (*datalen)--;
946 }
947
948 if (ssh->sccipher)
949 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
950 ssh->pktin.data, st->cipherblk);
951
952 /*
953 * Now get the length and padding figures.
954 */
955 st->len = GET_32BIT(ssh->pktin.data);
956 st->pad = ssh->pktin.data[4];
957
958 /*
959 * _Completely_ silly lengths should be stomped on before they
960 * do us any more damage.
961 */
962 if (st->len < 0 || st->pad < 0 || st->len + st->pad < 0) {
963 bombout((ssh,"Incoming packet was garbled on decryption"));
964 crReturn(0);
965 }
966
967 /*
968 * This enables us to deduce the payload length.
969 */
970 st->payload = st->len - st->pad - 1;
971
972 ssh->pktin.length = st->payload + 5;
973
974 /*
975 * So now we can work out the total packet length.
976 */
977 st->packetlen = st->len + 4;
978 st->maclen = ssh->scmac ? ssh->scmac->len : 0;
979
980 /*
981 * Adjust memory allocation if packet is too big.
982 */
983 if (ssh->pktin.maxlen < st->packetlen + st->maclen) {
984 ssh->pktin.maxlen = st->packetlen + st->maclen;
985 ssh->pktin.data = srealloc(ssh->pktin.data,
986 ssh->pktin.maxlen + APIEXTRA);
987 }
988
989 /*
990 * Read and decrypt the remainder of the packet.
991 */
992 for (st->i = st->cipherblk; st->i < st->packetlen + st->maclen;
993 st->i++) {
994 while ((*datalen) == 0)
995 crReturn(st->packetlen + st->maclen - st->i);
996 ssh->pktin.data[st->i] = *(*data)++;
997 (*datalen)--;
998 }
999 /* Decrypt everything _except_ the MAC. */
1000 if (ssh->sccipher)
1001 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
1002 ssh->pktin.data + st->cipherblk,
1003 st->packetlen - st->cipherblk);
1004
1005 /*
1006 * Check the MAC.
1007 */
1008 if (ssh->scmac
1009 && !ssh->scmac->verify(ssh->sc_mac_ctx, ssh->pktin.data, st->len + 4,
1010 st->incoming_sequence)) {
1011 bombout((ssh,"Incorrect MAC received on packet"));
1012 crReturn(0);
1013 }
1014 st->incoming_sequence++; /* whether or not we MACed */
1015
1016 /*
1017 * Decompress packet payload.
1018 */
1019 {
1020 unsigned char *newpayload;
1021 int newlen;
1022 if (ssh->sccomp &&
1023 ssh->sccomp->decompress(ssh->sc_comp_ctx,
1024 ssh->pktin.data + 5, ssh->pktin.length - 5,
1025 &newpayload, &newlen)) {
1026 if (ssh->pktin.maxlen < newlen + 5) {
1027 ssh->pktin.maxlen = newlen + 5;
1028 ssh->pktin.data = srealloc(ssh->pktin.data,
1029 ssh->pktin.maxlen + APIEXTRA);
1030 }
1031 ssh->pktin.length = 5 + newlen;
1032 memcpy(ssh->pktin.data + 5, newpayload, newlen);
1033 sfree(newpayload);
1034 }
1035 }
1036
1037 ssh->pktin.savedpos = 6;
1038 ssh->pktin.type = ssh->pktin.data[5];
1039
1040 if (ssh->logctx)
1041 log_packet(ssh->logctx, PKT_INCOMING, ssh->pktin.type,
1042 ssh2_pkt_type(ssh->pkt_ctx, ssh->pktin.type),
1043 ssh->pktin.data+6, ssh->pktin.length-6);
1044
1045 switch (ssh->pktin.type) {
1046 /*
1047 * These packets we must handle instantly.
1048 */
1049 case SSH2_MSG_DISCONNECT:
1050 {
1051 /* log reason code in disconnect message */
1052 char *buf;
1053 int nowlen;
1054 int reason = GET_32BIT(ssh->pktin.data + 6);
1055 unsigned msglen = GET_32BIT(ssh->pktin.data + 10);
1056
1057 if (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) {
1058 buf = dupprintf("Received disconnect message (%s)",
1059 ssh2_disconnect_reasons[reason]);
1060 } else {
1061 buf = dupprintf("Received disconnect message (unknown"
1062 " type %d)", reason);
1063 }
1064 logevent(buf);
1065 sfree(buf);
1066 buf = dupprintf("Disconnection message text: %n%.*s",
1067 &nowlen, msglen, ssh->pktin.data + 14);
1068 logevent(buf);
1069 bombout((ssh,"Server sent disconnect message\ntype %d (%s):\n\"%s\"",
1070 reason,
1071 (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) ?
1072 ssh2_disconnect_reasons[reason] : "unknown",
1073 buf+nowlen));
1074 sfree(buf);
1075 crReturn(0);
1076 }
1077 break;
1078 case SSH2_MSG_IGNORE:
1079 goto next_packet;
1080 case SSH2_MSG_DEBUG:
1081 {
1082 /* log the debug message */
1083 char buf[512];
1084 /* int display = ssh->pktin.body[6]; */
1085 int stringlen = GET_32BIT(ssh->pktin.data+7);
1086 int prefix;
1087 strcpy(buf, "Remote debug message: ");
1088 prefix = strlen(buf);
1089 if (stringlen > (int)(sizeof(buf)-prefix-1))
1090 stringlen = sizeof(buf)-prefix-1;
1091 memcpy(buf + prefix, ssh->pktin.data + 11, stringlen);
1092 buf[prefix + stringlen] = '\0';
1093 logevent(buf);
1094 }
1095 goto next_packet; /* FIXME: print the debug message */
1096
1097 /*
1098 * These packets we need do nothing about here.
1099 */
1100 case SSH2_MSG_UNIMPLEMENTED:
1101 case SSH2_MSG_SERVICE_REQUEST:
1102 case SSH2_MSG_SERVICE_ACCEPT:
1103 case SSH2_MSG_KEXINIT:
1104 case SSH2_MSG_NEWKEYS:
1105 case SSH2_MSG_KEXDH_INIT:
1106 case SSH2_MSG_KEXDH_REPLY:
1107 /* case SSH2_MSG_KEX_DH_GEX_REQUEST: duplicate case value */
1108 /* case SSH2_MSG_KEX_DH_GEX_GROUP: duplicate case value */
1109 case SSH2_MSG_KEX_DH_GEX_INIT:
1110 case SSH2_MSG_KEX_DH_GEX_REPLY:
1111 case SSH2_MSG_USERAUTH_REQUEST:
1112 case SSH2_MSG_USERAUTH_FAILURE:
1113 case SSH2_MSG_USERAUTH_SUCCESS:
1114 case SSH2_MSG_USERAUTH_BANNER:
1115 case SSH2_MSG_USERAUTH_PK_OK:
1116 /* case SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ: duplicate case value */
1117 /* case SSH2_MSG_USERAUTH_INFO_REQUEST: duplicate case value */
1118 case SSH2_MSG_USERAUTH_INFO_RESPONSE:
1119 case SSH2_MSG_GLOBAL_REQUEST:
1120 case SSH2_MSG_REQUEST_SUCCESS:
1121 case SSH2_MSG_REQUEST_FAILURE:
1122 case SSH2_MSG_CHANNEL_OPEN:
1123 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION:
1124 case SSH2_MSG_CHANNEL_OPEN_FAILURE:
1125 case SSH2_MSG_CHANNEL_WINDOW_ADJUST:
1126 case SSH2_MSG_CHANNEL_DATA:
1127 case SSH2_MSG_CHANNEL_EXTENDED_DATA:
1128 case SSH2_MSG_CHANNEL_EOF:
1129 case SSH2_MSG_CHANNEL_CLOSE:
1130 case SSH2_MSG_CHANNEL_REQUEST:
1131 case SSH2_MSG_CHANNEL_SUCCESS:
1132 case SSH2_MSG_CHANNEL_FAILURE:
1133 break;
1134
1135 /*
1136 * For anything else we send SSH2_MSG_UNIMPLEMENTED.
1137 */
1138 default:
1139 ssh2_pkt_init(ssh, SSH2_MSG_UNIMPLEMENTED);
1140 ssh2_pkt_adduint32(ssh, st->incoming_sequence - 1);
1141 ssh2_pkt_send(ssh);
1142 break;
1143 }
1144
1145 crFinish(0);
1146 }
1147
1148 static void ssh1_pktout_size(Ssh ssh, int len)
1149 {
1150 int pad, biglen;
1151
1152 len += 5; /* type and CRC */
1153 pad = 8 - (len % 8);
1154 biglen = len + pad;
1155
1156 ssh->pktout.length = len - 5;
1157 if (ssh->pktout.maxlen < biglen) {
1158 ssh->pktout.maxlen = biglen;
1159 #ifdef MSCRYPTOAPI
1160 /* Allocate enough buffer space for extra block
1161 * for MS CryptEncrypt() */
1162 ssh->pktout.data = srealloc(ssh->pktout.data, biglen + 12);
1163 #else
1164 ssh->pktout.data = srealloc(ssh->pktout.data, biglen + 4);
1165 #endif
1166 }
1167 ssh->pktout.body = ssh->pktout.data + 4 + pad + 1;
1168 }
1169
1170 static void s_wrpkt_start(Ssh ssh, int type, int len)
1171 {
1172 ssh1_pktout_size(ssh, len);
1173 ssh->pktout.type = type;
1174 }
1175
1176 static int s_wrpkt_prepare(Ssh ssh)
1177 {
1178 int pad, len, biglen, i;
1179 unsigned long crc;
1180
1181 ssh->pktout.body[-1] = ssh->pktout.type;
1182
1183 if (ssh->logctx)
1184 log_packet(ssh->logctx, PKT_OUTGOING, ssh->pktout.type,
1185 ssh1_pkt_type(ssh->pktout.type),
1186 ssh->pktout.body, ssh->pktout.length);
1187
1188 if (ssh->v1_compressing) {
1189 unsigned char *compblk;
1190 int complen;
1191 zlib_compress_block(ssh->cs_comp_ctx,
1192 ssh->pktout.body - 1, ssh->pktout.length + 1,
1193 &compblk, &complen);
1194 ssh1_pktout_size(ssh, complen - 1);
1195 memcpy(ssh->pktout.body - 1, compblk, complen);
1196 sfree(compblk);
1197 }
1198
1199 len = ssh->pktout.length + 5; /* type and CRC */
1200 pad = 8 - (len % 8);
1201 biglen = len + pad;
1202
1203 for (i = 0; i < pad; i++)
1204 ssh->pktout.data[i + 4] = random_byte();
1205 crc = crc32(ssh->pktout.data + 4, biglen - 4);
1206 PUT_32BIT(ssh->pktout.data + biglen, crc);
1207 PUT_32BIT(ssh->pktout.data, len);
1208
1209 if (ssh->cipher)
1210 ssh->cipher->encrypt(ssh->v1_cipher_ctx, ssh->pktout.data + 4, biglen);
1211
1212 return biglen + 4;
1213 }
1214
1215 static void s_wrpkt(Ssh ssh)
1216 {
1217 int len, backlog;
1218 len = s_wrpkt_prepare(ssh);
1219 backlog = sk_write(ssh->s, (char *)ssh->pktout.data, len);
1220 if (backlog > SSH_MAX_BACKLOG)
1221 ssh_throttle_all(ssh, 1, backlog);
1222 }
1223
1224 static void s_wrpkt_defer(Ssh ssh)
1225 {
1226 int len;
1227 len = s_wrpkt_prepare(ssh);
1228 if (ssh->deferred_len + len > ssh->deferred_size) {
1229 ssh->deferred_size = ssh->deferred_len + len + 128;
1230 ssh->deferred_send_data = srealloc(ssh->deferred_send_data,
1231 ssh->deferred_size);
1232 }
1233 memcpy(ssh->deferred_send_data + ssh->deferred_len, ssh->pktout.data, len);
1234 ssh->deferred_len += len;
1235 }
1236
1237 /*
1238 * Construct a packet with the specified contents.
1239 */
1240 static void construct_packet(Ssh ssh, int pkttype, va_list ap1, va_list ap2)
1241 {
1242 unsigned char *p, *argp, argchar;
1243 unsigned long argint;
1244 int pktlen, argtype, arglen;
1245 Bignum bn;
1246
1247 pktlen = 0;
1248 while ((argtype = va_arg(ap1, int)) != PKT_END) {
1249 switch (argtype) {
1250 case PKT_INT:
1251 (void) va_arg(ap1, int);
1252 pktlen += 4;
1253 break;
1254 case PKT_CHAR:
1255 (void) va_arg(ap1, int);
1256 pktlen++;
1257 break;
1258 case PKT_DATA:
1259 (void) va_arg(ap1, unsigned char *);
1260 arglen = va_arg(ap1, int);
1261 pktlen += arglen;
1262 break;
1263 case PKT_STR:
1264 argp = va_arg(ap1, unsigned char *);
1265 arglen = strlen((char *)argp);
1266 pktlen += 4 + arglen;
1267 break;
1268 case PKT_BIGNUM:
1269 bn = va_arg(ap1, Bignum);
1270 pktlen += ssh1_bignum_length(bn);
1271 break;
1272 default:
1273 assert(0);
1274 }
1275 }
1276
1277 s_wrpkt_start(ssh, pkttype, pktlen);
1278 p = ssh->pktout.body;
1279
1280 while ((argtype = va_arg(ap2, int)) != PKT_END) {
1281 switch (argtype) {
1282 case PKT_INT:
1283 argint = va_arg(ap2, int);
1284 PUT_32BIT(p, argint);
1285 p += 4;
1286 break;
1287 case PKT_CHAR:
1288 argchar = (unsigned char) va_arg(ap2, int);
1289 *p = argchar;
1290 p++;
1291 break;
1292 case PKT_DATA:
1293 argp = va_arg(ap2, unsigned char *);
1294 arglen = va_arg(ap2, int);
1295 memcpy(p, argp, arglen);
1296 p += arglen;
1297 break;
1298 case PKT_STR:
1299 argp = va_arg(ap2, unsigned char *);
1300 arglen = strlen((char *)argp);
1301 PUT_32BIT(p, arglen);
1302 memcpy(p + 4, argp, arglen);
1303 p += 4 + arglen;
1304 break;
1305 case PKT_BIGNUM:
1306 bn = va_arg(ap2, Bignum);
1307 p += ssh1_write_bignum(p, bn);
1308 break;
1309 }
1310 }
1311 }
1312
1313 static void send_packet(Ssh ssh, int pkttype, ...)
1314 {
1315 va_list ap1, ap2;
1316 va_start(ap1, pkttype);
1317 va_start(ap2, pkttype);
1318 construct_packet(ssh, pkttype, ap1, ap2);
1319 s_wrpkt(ssh);
1320 }
1321
1322 static void defer_packet(Ssh ssh, int pkttype, ...)
1323 {
1324 va_list ap1, ap2;
1325 va_start(ap1, pkttype);
1326 va_start(ap2, pkttype);
1327 construct_packet(ssh, pkttype, ap1, ap2);
1328 s_wrpkt_defer(ssh);
1329 }
1330
1331 static int ssh_versioncmp(char *a, char *b)
1332 {
1333 char *ae, *be;
1334 unsigned long av, bv;
1335
1336 av = strtoul(a, &ae, 10);
1337 bv = strtoul(b, &be, 10);
1338 if (av != bv)
1339 return (av < bv ? -1 : +1);
1340 if (*ae == '.')
1341 ae++;
1342 if (*be == '.')
1343 be++;
1344 av = strtoul(ae, &ae, 10);
1345 bv = strtoul(be, &be, 10);
1346 if (av != bv)
1347 return (av < bv ? -1 : +1);
1348 return 0;
1349 }
1350
1351 /*
1352 * Utility routines for putting an SSH-protocol `string' and
1353 * `uint32' into a SHA state.
1354 */
1355 #include <stdio.h>
1356 static void sha_string(SHA_State * s, void *str, int len)
1357 {
1358 unsigned char lenblk[4];
1359 PUT_32BIT(lenblk, len);
1360 SHA_Bytes(s, lenblk, 4);
1361 SHA_Bytes(s, str, len);
1362 }
1363
1364 static void sha_uint32(SHA_State * s, unsigned i)
1365 {
1366 unsigned char intblk[4];
1367 PUT_32BIT(intblk, i);
1368 SHA_Bytes(s, intblk, 4);
1369 }
1370
1371 /*
1372 * SSH2 packet construction functions.
1373 */
1374 static void ssh2_pkt_ensure(Ssh ssh, int length)
1375 {
1376 if (ssh->pktout.maxlen < length) {
1377 ssh->pktout.maxlen = length + 256;
1378 ssh->pktout.data = srealloc(ssh->pktout.data,
1379 ssh->pktout.maxlen + APIEXTRA);
1380 if (!ssh->pktout.data)
1381 fatalbox("Out of memory");
1382 }
1383 }
1384 static void ssh2_pkt_adddata(Ssh ssh, void *data, int len)
1385 {
1386 ssh->pktout.length += len;
1387 ssh2_pkt_ensure(ssh, ssh->pktout.length);
1388 memcpy(ssh->pktout.data + ssh->pktout.length - len, data, len);
1389 }
1390 static void ssh2_pkt_addbyte(Ssh ssh, unsigned char byte)
1391 {
1392 ssh2_pkt_adddata(ssh, &byte, 1);
1393 }
1394 static void ssh2_pkt_init(Ssh ssh, int pkt_type)
1395 {
1396 ssh->pktout.length = 5;
1397 ssh2_pkt_addbyte(ssh, (unsigned char) pkt_type);
1398 }
1399 static void ssh2_pkt_addbool(Ssh ssh, unsigned char value)
1400 {
1401 ssh2_pkt_adddata(ssh, &value, 1);
1402 }
1403 static void ssh2_pkt_adduint32(Ssh ssh, unsigned long value)
1404 {
1405 unsigned char x[4];
1406 PUT_32BIT(x, value);
1407 ssh2_pkt_adddata(ssh, x, 4);
1408 }
1409 static void ssh2_pkt_addstring_start(Ssh ssh)
1410 {
1411 ssh2_pkt_adduint32(ssh, 0);
1412 ssh->pktout.savedpos = ssh->pktout.length;
1413 }
1414 static void ssh2_pkt_addstring_str(Ssh ssh, char *data)
1415 {
1416 ssh2_pkt_adddata(ssh, data, strlen(data));
1417 PUT_32BIT(ssh->pktout.data + ssh->pktout.savedpos - 4,
1418 ssh->pktout.length - ssh->pktout.savedpos);
1419 }
1420 static void ssh2_pkt_addstring_data(Ssh ssh, char *data, int len)
1421 {
1422 ssh2_pkt_adddata(ssh, data, len);
1423 PUT_32BIT(ssh->pktout.data + ssh->pktout.savedpos - 4,
1424 ssh->pktout.length - ssh->pktout.savedpos);
1425 }
1426 static void ssh2_pkt_addstring(Ssh ssh, char *data)
1427 {
1428 ssh2_pkt_addstring_start(ssh);
1429 ssh2_pkt_addstring_str(ssh, data);
1430 }
1431 static unsigned char *ssh2_mpint_fmt(Bignum b, int *len)
1432 {
1433 unsigned char *p;
1434 int i, n = (bignum_bitcount(b) + 7) / 8;
1435 p = smalloc(n + 1);
1436 if (!p)
1437 fatalbox("out of memory");
1438 p[0] = 0;
1439 for (i = 1; i <= n; i++)
1440 p[i] = bignum_byte(b, n - i);
1441 i = 0;
1442 while (i <= n && p[i] == 0 && (p[i + 1] & 0x80) == 0)
1443 i++;
1444 memmove(p, p + i, n + 1 - i);
1445 *len = n + 1 - i;
1446 return p;
1447 }
1448 static void ssh2_pkt_addmp(Ssh ssh, Bignum b)
1449 {
1450 unsigned char *p;
1451 int len;
1452 p = ssh2_mpint_fmt(b, &len);
1453 ssh2_pkt_addstring_start(ssh);
1454 ssh2_pkt_addstring_data(ssh, (char *)p, len);
1455 sfree(p);
1456 }
1457
1458 /*
1459 * Construct an SSH2 final-form packet: compress it, encrypt it,
1460 * put the MAC on it. Final packet, ready to be sent, is stored in
1461 * ssh->pktout.data. Total length is returned.
1462 */
1463 static int ssh2_pkt_construct(Ssh ssh)
1464 {
1465 int cipherblk, maclen, padding, i;
1466
1467 if (ssh->logctx)
1468 log_packet(ssh->logctx, PKT_OUTGOING, ssh->pktout.data[5],
1469 ssh2_pkt_type(ssh->pkt_ctx, ssh->pktout.data[5]),
1470 ssh->pktout.data + 6, ssh->pktout.length - 6);
1471
1472 /*
1473 * Compress packet payload.
1474 */
1475 {
1476 unsigned char *newpayload;
1477 int newlen;
1478 if (ssh->cscomp &&
1479 ssh->cscomp->compress(ssh->cs_comp_ctx, ssh->pktout.data + 5,
1480 ssh->pktout.length - 5,
1481 &newpayload, &newlen)) {
1482 ssh->pktout.length = 5;
1483 ssh2_pkt_adddata(ssh, newpayload, newlen);
1484 sfree(newpayload);
1485 }
1486 }
1487
1488 /*
1489 * Add padding. At least four bytes, and must also bring total
1490 * length (minus MAC) up to a multiple of the block size.
1491 */
1492 cipherblk = ssh->cscipher ? ssh->cscipher->blksize : 8; /* block size */
1493 cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */
1494 padding = 4;
1495 padding +=
1496 (cipherblk - (ssh->pktout.length + padding) % cipherblk) % cipherblk;
1497 maclen = ssh->csmac ? ssh->csmac->len : 0;
1498 ssh2_pkt_ensure(ssh, ssh->pktout.length + padding + maclen);
1499 ssh->pktout.data[4] = padding;
1500 for (i = 0; i < padding; i++)
1501 ssh->pktout.data[ssh->pktout.length + i] = random_byte();
1502 PUT_32BIT(ssh->pktout.data, ssh->pktout.length + padding - 4);
1503 if (ssh->csmac)
1504 ssh->csmac->generate(ssh->cs_mac_ctx, ssh->pktout.data,
1505 ssh->pktout.length + padding,
1506 ssh->v2_outgoing_sequence);
1507 ssh->v2_outgoing_sequence++; /* whether or not we MACed */
1508
1509 if (ssh->cscipher)
1510 ssh->cscipher->encrypt(ssh->cs_cipher_ctx,
1511 ssh->pktout.data, ssh->pktout.length + padding);
1512
1513 /* Ready-to-send packet starts at ssh->pktout.data. We return length. */
1514 return ssh->pktout.length + padding + maclen;
1515 }
1516
1517 /*
1518 * Construct and send an SSH2 packet immediately.
1519 */
1520 static void ssh2_pkt_send(Ssh ssh)
1521 {
1522 int len;
1523 int backlog;
1524 len = ssh2_pkt_construct(ssh);
1525 backlog = sk_write(ssh->s, (char *)ssh->pktout.data, len);
1526 if (backlog > SSH_MAX_BACKLOG)
1527 ssh_throttle_all(ssh, 1, backlog);
1528 }
1529
1530 /*
1531 * Construct an SSH2 packet and add it to a deferred data block.
1532 * Useful for sending multiple packets in a single sk_write() call,
1533 * to prevent a traffic-analysing listener from being able to work
1534 * out the length of any particular packet (such as the password
1535 * packet).
1536 *
1537 * Note that because SSH2 sequence-numbers its packets, this can
1538 * NOT be used as an m4-style `defer' allowing packets to be
1539 * constructed in one order and sent in another.
1540 */
1541 static void ssh2_pkt_defer(Ssh ssh)
1542 {
1543 int len = ssh2_pkt_construct(ssh);
1544 if (ssh->deferred_len + len > ssh->deferred_size) {
1545 ssh->deferred_size = ssh->deferred_len + len + 128;
1546 ssh->deferred_send_data = srealloc(ssh->deferred_send_data,
1547 ssh->deferred_size);
1548 }
1549 memcpy(ssh->deferred_send_data + ssh->deferred_len, ssh->pktout.data, len);
1550 ssh->deferred_len += len;
1551 }
1552
1553 /*
1554 * Send the whole deferred data block constructed by
1555 * ssh2_pkt_defer() or SSH1's defer_packet().
1556 */
1557 static void ssh_pkt_defersend(Ssh ssh)
1558 {
1559 int backlog;
1560 backlog = sk_write(ssh->s, (char *)ssh->deferred_send_data,
1561 ssh->deferred_len);
1562 ssh->deferred_len = ssh->deferred_size = 0;
1563 sfree(ssh->deferred_send_data);
1564 ssh->deferred_send_data = NULL;
1565 if (backlog > SSH_MAX_BACKLOG)
1566 ssh_throttle_all(ssh, 1, backlog);
1567 }
1568
1569 #if 0
1570 void bndebug(char *string, Bignum b)
1571 {
1572 unsigned char *p;
1573 int i, len;
1574 p = ssh2_mpint_fmt(b, &len);
1575 debug(("%s", string));
1576 for (i = 0; i < len; i++)
1577 debug((" %02x", p[i]));
1578 debug(("\n"));
1579 sfree(p);
1580 }
1581 #endif
1582
1583 static void sha_mpint(SHA_State * s, Bignum b)
1584 {
1585 unsigned char *p;
1586 int len;
1587 p = ssh2_mpint_fmt(b, &len);
1588 sha_string(s, p, len);
1589 sfree(p);
1590 }
1591
1592 /*
1593 * SSH2 packet decode functions.
1594 */
1595 static unsigned long ssh2_pkt_getuint32(Ssh ssh)
1596 {
1597 unsigned long value;
1598 if (ssh->pktin.length - ssh->pktin.savedpos < 4)
1599 return 0; /* arrgh, no way to decline (FIXME?) */
1600 value = GET_32BIT(ssh->pktin.data + ssh->pktin.savedpos);
1601 ssh->pktin.savedpos += 4;
1602 return value;
1603 }
1604 static int ssh2_pkt_getbool(Ssh ssh)
1605 {
1606 unsigned long value;
1607 if (ssh->pktin.length - ssh->pktin.savedpos < 1)
1608 return 0; /* arrgh, no way to decline (FIXME?) */
1609 value = ssh->pktin.data[ssh->pktin.savedpos] != 0;
1610 ssh->pktin.savedpos++;
1611 return value;
1612 }
1613 static void ssh2_pkt_getstring(Ssh ssh, char **p, int *length)
1614 {
1615 int len;
1616 *p = NULL;
1617 *length = 0;
1618 if (ssh->pktin.length - ssh->pktin.savedpos < 4)
1619 return;
1620 len = GET_32BIT(ssh->pktin.data + ssh->pktin.savedpos);
1621 if (len < 0)
1622 return;
1623 *length = len;
1624 ssh->pktin.savedpos += 4;
1625 if (ssh->pktin.length - ssh->pktin.savedpos < *length)
1626 return;
1627 *p = (char *)(ssh->pktin.data + ssh->pktin.savedpos);
1628 ssh->pktin.savedpos += *length;
1629 }
1630 static Bignum ssh2_pkt_getmp(Ssh ssh)
1631 {
1632 char *p;
1633 int length;
1634 Bignum b;
1635
1636 ssh2_pkt_getstring(ssh, &p, &length);
1637 if (!p)
1638 return NULL;
1639 if (p[0] & 0x80) {
1640 bombout((ssh,"internal error: Can't handle negative mpints"));
1641 return NULL;
1642 }
1643 b = bignum_from_bytes((unsigned char *)p, length);
1644 return b;
1645 }
1646
1647 /*
1648 * Helper function to add an SSH2 signature blob to a packet.
1649 * Expects to be shown the public key blob as well as the signature
1650 * blob. Normally works just like ssh2_pkt_addstring, but will
1651 * fiddle with the signature packet if necessary for
1652 * BUG_SSH2_RSA_PADDING.
1653 */
1654 static void ssh2_add_sigblob(Ssh ssh, void *pkblob_v, int pkblob_len,
1655 void *sigblob_v, int sigblob_len)
1656 {
1657 unsigned char *pkblob = (unsigned char *)pkblob_v;
1658 unsigned char *sigblob = (unsigned char *)sigblob_v;
1659
1660 /* dmemdump(pkblob, pkblob_len); */
1661 /* dmemdump(sigblob, sigblob_len); */
1662
1663 /*
1664 * See if this is in fact an ssh-rsa signature and a buggy
1665 * server; otherwise we can just do this the easy way.
1666 */
1667 if ((ssh->remote_bugs & BUG_SSH2_RSA_PADDING) &&
1668 (GET_32BIT(pkblob) == 7 && !memcmp(pkblob+4, "ssh-rsa", 7))) {
1669 int pos, len, siglen;
1670
1671 /*
1672 * Find the byte length of the modulus.
1673 */
1674
1675 pos = 4+7; /* skip over "ssh-rsa" */
1676 pos += 4 + GET_32BIT(pkblob+pos); /* skip over exponent */
1677 len = GET_32BIT(pkblob+pos); /* find length of modulus */
1678 pos += 4; /* find modulus itself */
1679 while (len > 0 && pkblob[pos] == 0)
1680 len--, pos++;
1681 /* debug(("modulus length is %d\n", len)); */
1682
1683 /*
1684 * Now find the signature integer.
1685 */
1686 pos = 4+7; /* skip over "ssh-rsa" */
1687 siglen = GET_32BIT(sigblob+pos);
1688 /* debug(("signature length is %d\n", siglen)); */
1689
1690 if (len != siglen) {
1691 unsigned char newlen[4];
1692 ssh2_pkt_addstring_start(ssh);
1693 ssh2_pkt_addstring_data(ssh, (char *)sigblob, pos);
1694 /* dmemdump(sigblob, pos); */
1695 pos += 4; /* point to start of actual sig */
1696 PUT_32BIT(newlen, len);
1697 ssh2_pkt_addstring_data(ssh, (char *)newlen, 4);
1698 /* dmemdump(newlen, 4); */
1699 newlen[0] = 0;
1700 while (len-- > siglen) {
1701 ssh2_pkt_addstring_data(ssh, (char *)newlen, 1);
1702 /* dmemdump(newlen, 1); */
1703 }
1704 ssh2_pkt_addstring_data(ssh, (char *)(sigblob+pos), siglen);
1705 /* dmemdump(sigblob+pos, siglen); */
1706 return;
1707 }
1708
1709 /* Otherwise fall through and do it the easy way. */
1710 }
1711
1712 ssh2_pkt_addstring_start(ssh);
1713 ssh2_pkt_addstring_data(ssh, (char *)sigblob, sigblob_len);
1714 }
1715
1716 /*
1717 * Examine the remote side's version string and compare it against
1718 * a list of known buggy implementations.
1719 */
1720 static void ssh_detect_bugs(Ssh ssh, char *vstring)
1721 {
1722 char *imp; /* pointer to implementation part */
1723 imp = vstring;
1724 imp += strcspn(imp, "-");
1725 if (*imp) imp++;
1726 imp += strcspn(imp, "-");
1727 if (*imp) imp++;
1728
1729 ssh->remote_bugs = 0;
1730
1731 if (cfg.sshbug_ignore1 == BUG_ON ||
1732 (cfg.sshbug_ignore1 == BUG_AUTO &&
1733 (!strcmp(imp, "1.2.18") || !strcmp(imp, "1.2.19") ||
1734 !strcmp(imp, "1.2.20") || !strcmp(imp, "1.2.21") ||
1735 !strcmp(imp, "1.2.22") || !strcmp(imp, "Cisco-1.25")))) {
1736 /*
1737 * These versions don't support SSH1_MSG_IGNORE, so we have
1738 * to use a different defence against password length
1739 * sniffing.
1740 */
1741 ssh->remote_bugs |= BUG_CHOKES_ON_SSH1_IGNORE;
1742 logevent("We believe remote version has SSH1 ignore bug");
1743 }
1744
1745 if (cfg.sshbug_plainpw1 == BUG_ON ||
1746 (cfg.sshbug_plainpw1 == BUG_AUTO &&
1747 (!strcmp(imp, "Cisco-1.25")))) {
1748 /*
1749 * These versions need a plain password sent; they can't
1750 * handle having a null and a random length of data after
1751 * the password.
1752 */
1753 ssh->remote_bugs |= BUG_NEEDS_SSH1_PLAIN_PASSWORD;
1754 logevent("We believe remote version needs a plain SSH1 password");
1755 }
1756
1757 if (cfg.sshbug_rsa1 == BUG_ON ||
1758 (cfg.sshbug_rsa1 == BUG_AUTO &&
1759 (!strcmp(imp, "Cisco-1.25")))) {
1760 /*
1761 * These versions apparently have no clue whatever about
1762 * RSA authentication and will panic and die if they see
1763 * an AUTH_RSA message.
1764 */
1765 ssh->remote_bugs |= BUG_CHOKES_ON_RSA;
1766 logevent("We believe remote version can't handle RSA authentication");
1767 }
1768
1769 if (cfg.sshbug_hmac2 == BUG_ON ||
1770 (cfg.sshbug_hmac2 == BUG_AUTO &&
1771 (wc_match("2.1.0*", imp) || wc_match("2.0.*", imp) ||
1772 wc_match("2.2.0*", imp) || wc_match("2.3.0*", imp) ||
1773 wc_match("2.1 *", imp)))) {
1774 /*
1775 * These versions have the HMAC bug.
1776 */
1777 ssh->remote_bugs |= BUG_SSH2_HMAC;
1778 logevent("We believe remote version has SSH2 HMAC bug");
1779 }
1780
1781 if (cfg.sshbug_derivekey2 == BUG_ON ||
1782 (cfg.sshbug_derivekey2 == BUG_AUTO &&
1783 (wc_match("2.0.0*", imp) || wc_match("2.0.1[01]*", imp) ))) {
1784 /*
1785 * These versions have the key-derivation bug (failing to
1786 * include the literal shared secret in the hashes that
1787 * generate the keys).
1788 */
1789 ssh->remote_bugs |= BUG_SSH2_DERIVEKEY;
1790 logevent("We believe remote version has SSH2 key-derivation bug");
1791 }
1792
1793 if (cfg.sshbug_rsapad2 == BUG_ON ||
1794 (cfg.sshbug_rsapad2 == BUG_AUTO &&
1795 (wc_match("OpenSSH_2.[5-9]*", imp) ||
1796 wc_match("OpenSSH_3.[0-2]*", imp)))) {
1797 /*
1798 * These versions have the SSH2 RSA padding bug.
1799 */
1800 ssh->remote_bugs |= BUG_SSH2_RSA_PADDING;
1801 logevent("We believe remote version has SSH2 RSA padding bug");
1802 }
1803
1804 if (cfg.sshbug_dhgex2 == BUG_ON) {
1805 /*
1806 * User specified the SSH2 DH GEX bug.
1807 */
1808 ssh->remote_bugs |= BUG_SSH2_DH_GEX;
1809 logevent("We believe remote version has SSH2 DH group exchange bug");
1810 }
1811 }
1812
1813 static int do_ssh_init(Ssh ssh, unsigned char c)
1814 {
1815 struct do_ssh_init_state {
1816 int vslen;
1817 char version[10];
1818 char *vstring;
1819 int vstrsize;
1820 int i;
1821 int proto1, proto2;
1822 };
1823 crState(do_ssh_init_state);
1824
1825 crBegin(ssh->do_ssh_init_crstate);
1826
1827 /* Search for the string "SSH-" in the input. */
1828 s->i = 0;
1829 while (1) {
1830 static const int transS[] = { 1, 2, 2, 1 };
1831 static const int transH[] = { 0, 0, 3, 0 };
1832 static const int transminus[] = { 0, 0, 0, -1 };
1833 if (c == 'S')
1834 s->i = transS[s->i];
1835 else if (c == 'H')
1836 s->i = transH[s->i];
1837 else if (c == '-')
1838 s->i = transminus[s->i];
1839 else
1840 s->i = 0;
1841 if (s->i < 0)
1842 break;
1843 crReturn(1); /* get another character */
1844 }
1845
1846 s->vstrsize = 16;
1847 s->vstring = smalloc(s->vstrsize);
1848 strcpy(s->vstring, "SSH-");
1849 s->vslen = 4;
1850 s->i = 0;
1851 while (1) {
1852 crReturn(1); /* get another char */
1853 if (s->vslen >= s->vstrsize - 1) {
1854 s->vstrsize += 16;
1855 s->vstring = srealloc(s->vstring, s->vstrsize);
1856 }
1857 s->vstring[s->vslen++] = c;
1858 if (s->i >= 0) {
1859 if (c == '-') {
1860 s->version[s->i] = '\0';
1861 s->i = -1;
1862 } else if (s->i < sizeof(s->version) - 1)
1863 s->version[s->i++] = c;
1864 } else if (c == '\n')
1865 break;
1866 }
1867
1868 ssh->agentfwd_enabled = FALSE;
1869 ssh->rdpkt2_state.incoming_sequence = 0;
1870
1871 s->vstring[s->vslen] = 0;
1872 s->vstring[strcspn(s->vstring, "\r\n")] = '\0';/* remove EOL chars */
1873 {
1874 char *vlog;
1875 vlog = smalloc(20 + s->vslen);
1876 sprintf(vlog, "Server version: %s", s->vstring);
1877 logevent(vlog);
1878 sfree(vlog);
1879 }
1880 ssh_detect_bugs(ssh, s->vstring);
1881
1882 /*
1883 * Decide which SSH protocol version to support.
1884 */
1885
1886 /* Anything strictly below "2.0" means protocol 1 is supported. */
1887 s->proto1 = ssh_versioncmp(s->version, "2.0") < 0;
1888 /* Anything greater or equal to "1.99" means protocol 2 is supported. */
1889 s->proto2 = ssh_versioncmp(s->version, "1.99") >= 0;
1890
1891 if (cfg.sshprot == 0 && !s->proto1) {
1892 bombout((ssh,"SSH protocol version 1 required by user but not provided by server"));
1893 crReturn(0);
1894 }
1895 if (cfg.sshprot == 3 && !s->proto2) {
1896 bombout((ssh,"SSH protocol version 2 required by user but not provided by server"));
1897 crReturn(0);
1898 }
1899
1900 if (s->proto2 && (cfg.sshprot >= 2 || !s->proto1)) {
1901 /*
1902 * Use v2 protocol.
1903 */
1904 char verstring[80], vlog[100];
1905 sprintf(verstring, "SSH-2.0-%s", sshver);
1906 SHA_Init(&ssh->exhashbase);
1907 /*
1908 * Hash our version string and their version string.
1909 */
1910 sha_string(&ssh->exhashbase, verstring, strlen(verstring));
1911 sha_string(&ssh->exhashbase, s->vstring, strcspn(s->vstring, "\r\n"));
1912 sprintf(vlog, "We claim version: %s", verstring);
1913 logevent(vlog);
1914 strcat(verstring, "\n");
1915 logevent("Using SSH protocol version 2");
1916 sk_write(ssh->s, verstring, strlen(verstring));
1917 ssh->protocol = ssh2_protocol;
1918 ssh->version = 2;
1919 ssh->s_rdpkt = ssh2_rdpkt;
1920 } else {
1921 /*
1922 * Use v1 protocol.
1923 */
1924 char verstring[80], vlog[100];
1925 sprintf(verstring, "SSH-%s-%s",
1926 (ssh_versioncmp(s->version, "1.5") <= 0 ? s->version : "1.5"),
1927 sshver);
1928 sprintf(vlog, "We claim version: %s", verstring);
1929 logevent(vlog);
1930 strcat(verstring, "\n");
1931
1932 logevent("Using SSH protocol version 1");
1933 sk_write(ssh->s, verstring, strlen(verstring));
1934 ssh->protocol = ssh1_protocol;
1935 ssh->version = 1;
1936 ssh->s_rdpkt = ssh1_rdpkt;
1937 }
1938 ssh->state = SSH_STATE_BEFORE_SIZE;
1939
1940 sfree(s->vstring);
1941
1942 crFinish(0);
1943 }
1944
1945 static void ssh_gotdata(Ssh ssh, unsigned char *data, int datalen)
1946 {
1947 crBegin(ssh->ssh_gotdata_crstate);
1948
1949 /*
1950 * To begin with, feed the characters one by one to the
1951 * protocol initialisation / selection function do_ssh_init().
1952 * When that returns 0, we're done with the initial greeting
1953 * exchange and can move on to packet discipline.
1954 */
1955 while (1) {
1956 int ret; /* need not be kept across crReturn */
1957 if (datalen == 0)
1958 crReturnV; /* more data please */
1959 ret = do_ssh_init(ssh, *data);
1960 data++;
1961 datalen--;
1962 if (ret == 0)
1963 break;
1964 }
1965
1966 /*
1967 * We emerge from that loop when the initial negotiation is
1968 * over and we have selected an s_rdpkt function. Now pass
1969 * everything to s_rdpkt, and then pass the resulting packets
1970 * to the proper protocol handler.
1971 */
1972 if (datalen == 0)
1973 crReturnV;
1974 while (1) {
1975 while (datalen > 0) {
1976 if (ssh->s_rdpkt(ssh, &data, &datalen) == 0) {
1977 if (ssh->state == SSH_STATE_CLOSED) {
1978 return;
1979 }
1980 ssh->protocol(ssh, NULL, 0, 1);
1981 if (ssh->state == SSH_STATE_CLOSED) {
1982 return;
1983 }
1984 }
1985 }
1986 crReturnV;
1987 }
1988 crFinishV;
1989 }
1990
1991 static int ssh_closing(Plug plug, char *error_msg, int error_code,
1992 int calling_back)
1993 {
1994 Ssh ssh = (Ssh) plug;
1995 ssh->state = SSH_STATE_CLOSED;
1996 if (ssh->s) {
1997 sk_close(ssh->s);
1998 ssh->s = NULL;
1999 }
2000 if (error_msg) {
2001 /* A socket error has occurred. */
2002 logevent(error_msg);
2003 connection_fatal(ssh->frontend, error_msg);
2004 } else {
2005 /* Otherwise, the remote side closed the connection normally. */
2006 }
2007 return 0;
2008 }
2009
2010 static int ssh_receive(Plug plug, int urgent, char *data, int len)
2011 {
2012 Ssh ssh = (Ssh) plug;
2013 ssh_gotdata(ssh, (unsigned char *)data, len);
2014 if (ssh->state == SSH_STATE_CLOSED) {
2015 if (ssh->s) {
2016 sk_close(ssh->s);
2017 ssh->s = NULL;
2018 }
2019 return 0;
2020 }
2021 return 1;
2022 }
2023
2024 static void ssh_sent(Plug plug, int bufsize)
2025 {
2026 Ssh ssh = (Ssh) plug;
2027 /*
2028 * If the send backlog on the SSH socket itself clears, we
2029 * should unthrottle the whole world if it was throttled.
2030 */
2031 if (bufsize < SSH_MAX_BACKLOG)
2032 ssh_throttle_all(ssh, 0, bufsize);
2033 }
2034
2035 /*
2036 * Connect to specified host and port.
2037 * Returns an error message, or NULL on success.
2038 * Also places the canonical host name into `realhost'. It must be
2039 * freed by the caller.
2040 */
2041 static char *connect_to_host(Ssh ssh, char *host, int port,
2042 char **realhost, int nodelay)
2043 {
2044 static const struct plug_function_table fn_table = {
2045 ssh_closing,
2046 ssh_receive,
2047 ssh_sent,
2048 NULL
2049 };
2050
2051 SockAddr addr;
2052 char *err;
2053
2054 ssh->savedhost = smalloc(1 + strlen(host));
2055 if (!ssh->savedhost)
2056 fatalbox("Out of memory");
2057 strcpy(ssh->savedhost, host);
2058
2059 if (port < 0)
2060 port = 22; /* default ssh port */
2061 ssh->savedport = port;
2062
2063 /*
2064 * Try to find host.
2065 */
2066 logeventf(ssh, "Looking up host \"%s\"", host);
2067 addr = name_lookup(host, port, realhost);
2068 if ((err = sk_addr_error(addr)) != NULL)
2069 return err;
2070
2071 /*
2072 * Open socket.
2073 */
2074 {
2075 char addrbuf[100];
2076 sk_getaddr(addr, addrbuf, 100);
2077 logeventf(ssh, "Connecting to %s port %d", addrbuf, port);
2078 }
2079 ssh->fn = &fn_table;
2080 ssh->s = new_connection(addr, *realhost, port, 0, 1, nodelay, (Plug) ssh);
2081 if ((err = sk_socket_error(ssh->s)) != NULL) {
2082 ssh->s = NULL;
2083 return err;
2084 }
2085
2086 return NULL;
2087 }
2088
2089 /*
2090 * Throttle or unthrottle the SSH connection.
2091 */
2092 static void ssh1_throttle(Ssh ssh, int adjust)
2093 {
2094 int old_count = ssh->v1_throttle_count;
2095 ssh->v1_throttle_count += adjust;
2096 assert(ssh->v1_throttle_count >= 0);
2097 if (ssh->v1_throttle_count && !old_count) {
2098 sk_set_frozen(ssh->s, 1);
2099 } else if (!ssh->v1_throttle_count && old_count) {
2100 sk_set_frozen(ssh->s, 0);
2101 }
2102 }
2103
2104 /*
2105 * Throttle or unthrottle _all_ local data streams (for when sends
2106 * on the SSH connection itself back up).
2107 */
2108 static void ssh_throttle_all(Ssh ssh, int enable, int bufsize)
2109 {
2110 int i;
2111 struct ssh_channel *c;
2112
2113 if (enable == ssh->throttled_all)
2114 return;
2115 ssh->throttled_all = enable;
2116 ssh->overall_bufsize = bufsize;
2117 if (!ssh->channels)
2118 return;
2119 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
2120 switch (c->type) {
2121 case CHAN_MAINSESSION:
2122 /*
2123 * This is treated separately, outside the switch.
2124 */
2125 break;
2126 case CHAN_X11:
2127 x11_override_throttle(c->u.x11.s, enable);
2128 break;
2129 case CHAN_AGENT:
2130 /* Agent channels require no buffer management. */
2131 break;
2132 case CHAN_SOCKDATA:
2133 pfd_override_throttle(c->u.x11.s, enable);
2134 break;
2135 }
2136 }
2137 }
2138
2139 /*
2140 * Username and password input, abstracted off into routines
2141 * reusable in several places - even between SSH1 and SSH2.
2142 */
2143
2144 /* Set up a username or password input loop on a given buffer. */
2145 void setup_userpass_input(Ssh ssh, char *buffer, int buflen, int echo)
2146 {
2147 ssh->userpass_input_buffer = buffer;
2148 ssh->userpass_input_buflen = buflen;
2149 ssh->userpass_input_bufpos = 0;
2150 ssh->userpass_input_echo = echo;
2151 }
2152
2153 /*
2154 * Process some terminal data in the course of username/password
2155 * input. Returns >0 for success (line of input returned in
2156 * buffer), <0 for failure (user hit ^C/^D, bomb out and exit), 0
2157 * for inconclusive (keep waiting for more input please).
2158 */
2159 int process_userpass_input(Ssh ssh, unsigned char *in, int inlen)
2160 {
2161 char c;
2162
2163 while (inlen--) {
2164 switch (c = *in++) {
2165 case 10:
2166 case 13:
2167 ssh->userpass_input_buffer[ssh->userpass_input_bufpos] = 0;
2168 ssh->userpass_input_buffer[ssh->userpass_input_buflen-1] = 0;
2169 return +1;
2170 break;
2171 case 8:
2172 case 127:
2173 if (ssh->userpass_input_bufpos > 0) {
2174 if (ssh->userpass_input_echo)
2175 c_write_str(ssh, "\b \b");
2176 ssh->userpass_input_bufpos--;
2177 }
2178 break;
2179 case 21:
2180 case 27:
2181 while (ssh->userpass_input_bufpos > 0) {
2182 if (ssh->userpass_input_echo)
2183 c_write_str(ssh, "\b \b");
2184 ssh->userpass_input_bufpos--;
2185 }
2186 break;
2187 case 3:
2188 case 4:
2189 return -1;
2190 break;
2191 default:
2192 if (((c >= ' ' && c <= '~') ||
2193 ((unsigned char) c >= 160))
2194 && ssh->userpass_input_bufpos < ssh->userpass_input_buflen-1) {
2195 ssh->userpass_input_buffer[ssh->userpass_input_bufpos++] = c;
2196 if (ssh->userpass_input_echo)
2197 c_write(ssh, &c, 1);
2198 }
2199 break;
2200 }
2201 }
2202 return 0;
2203 }
2204
2205 /*
2206 * Handle the key exchange and user authentication phases.
2207 */
2208 static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
2209 {
2210 int i, j;
2211 unsigned char cookie[8];
2212 struct RSAKey servkey, hostkey;
2213 struct MD5Context md5c;
2214 struct do_ssh1_login_state {
2215 int len;
2216 unsigned char *rsabuf, *keystr1, *keystr2;
2217 unsigned long supported_ciphers_mask, supported_auths_mask;
2218 int tried_publickey, tried_agent;
2219 int tis_auth_refused, ccard_auth_refused;
2220 unsigned char session_id[16];
2221 int cipher_type;
2222 char username[100];
2223 void *publickey_blob;
2224 int publickey_bloblen;
2225 char password[100];
2226 char prompt[200];
2227 int pos;
2228 char c;
2229 int pwpkt_type;
2230 unsigned char request[5], *response, *p;
2231 int responselen;
2232 int keyi, nkeys;
2233 int authed;
2234 struct RSAKey key;
2235 Bignum challenge;
2236 char *commentp;
2237 int commentlen;
2238 };
2239 crState(do_ssh1_login_state);
2240
2241 crBegin(ssh->do_ssh1_login_crstate);
2242
2243 if (!ispkt)
2244 crWaitUntil(ispkt);
2245
2246 if (ssh->pktin.type != SSH1_SMSG_PUBLIC_KEY) {
2247 bombout((ssh,"Public key packet not received"));
2248 crReturn(0);
2249 }
2250
2251 logevent("Received public keys");
2252
2253 memcpy(cookie, ssh->pktin.body, 8);
2254
2255 i = makekey(ssh->pktin.body + 8, &servkey, &s->keystr1, 0);
2256 j = makekey(ssh->pktin.body + 8 + i, &hostkey, &s->keystr2, 0);
2257
2258 /*
2259 * Log the host key fingerprint.
2260 */
2261 {
2262 char logmsg[80];
2263 logevent("Host key fingerprint is:");
2264 strcpy(logmsg, " ");
2265 hostkey.comment = NULL;
2266 rsa_fingerprint(logmsg + strlen(logmsg),
2267 sizeof(logmsg) - strlen(logmsg), &hostkey);
2268 logevent(logmsg);
2269 }
2270
2271 ssh->v1_remote_protoflags = GET_32BIT(ssh->pktin.body + 8 + i + j);
2272 s->supported_ciphers_mask = GET_32BIT(ssh->pktin.body + 12 + i + j);
2273 s->supported_auths_mask = GET_32BIT(ssh->pktin.body + 16 + i + j);
2274
2275 ssh->v1_local_protoflags =
2276 ssh->v1_remote_protoflags & SSH1_PROTOFLAGS_SUPPORTED;
2277 ssh->v1_local_protoflags |= SSH1_PROTOFLAG_SCREEN_NUMBER;
2278
2279 MD5Init(&md5c);
2280 MD5Update(&md5c, s->keystr2, hostkey.bytes);
2281 MD5Update(&md5c, s->keystr1, servkey.bytes);
2282 MD5Update(&md5c, ssh->pktin.body, 8);
2283 MD5Final(s->session_id, &md5c);
2284
2285 for (i = 0; i < 32; i++)
2286 ssh->session_key[i] = random_byte();
2287
2288 s->len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes);
2289
2290 s->rsabuf = smalloc(s->len);
2291 if (!s->rsabuf)
2292 fatalbox("Out of memory");
2293
2294 /*
2295 * Verify the host key.
2296 */
2297 {
2298 /*
2299 * First format the key into a string.
2300 */
2301 int len = rsastr_len(&hostkey);
2302 char fingerprint[100];
2303 char *keystr = smalloc(len);
2304 if (!keystr)
2305 fatalbox("Out of memory");
2306 rsastr_fmt(keystr, &hostkey);
2307 rsa_fingerprint(fingerprint, sizeof(fingerprint), &hostkey);
2308 verify_ssh_host_key(ssh->frontend,
2309 ssh->savedhost, ssh->savedport, "rsa", keystr,
2310 fingerprint);
2311 sfree(keystr);
2312 }
2313
2314 for (i = 0; i < 32; i++) {
2315 s->rsabuf[i] = ssh->session_key[i];
2316 if (i < 16)
2317 s->rsabuf[i] ^= s->session_id[i];
2318 }
2319
2320 if (hostkey.bytes > servkey.bytes) {
2321 rsaencrypt(s->rsabuf, 32, &servkey);
2322 rsaencrypt(s->rsabuf, servkey.bytes, &hostkey);
2323 } else {
2324 rsaencrypt(s->rsabuf, 32, &hostkey);
2325 rsaencrypt(s->rsabuf, hostkey.bytes, &servkey);
2326 }
2327
2328 logevent("Encrypted session key");
2329
2330 {
2331 int cipher_chosen = 0, warn = 0;
2332 char *cipher_string = NULL;
2333 int i;
2334 for (i = 0; !cipher_chosen && i < CIPHER_MAX; i++) {
2335 int next_cipher = cfg.ssh_cipherlist[i];
2336 if (next_cipher == CIPHER_WARN) {
2337 /* If/when we choose a cipher, warn about it */
2338 warn = 1;
2339 } else if (next_cipher == CIPHER_AES) {
2340 /* XXX Probably don't need to mention this. */
2341 logevent("AES not supported in SSH1, skipping");
2342 } else {
2343 switch (next_cipher) {
2344 case CIPHER_3DES: s->cipher_type = SSH_CIPHER_3DES;
2345 cipher_string = "3DES"; break;
2346 case CIPHER_BLOWFISH: s->cipher_type = SSH_CIPHER_BLOWFISH;
2347 cipher_string = "Blowfish"; break;
2348 case CIPHER_DES: s->cipher_type = SSH_CIPHER_DES;
2349 cipher_string = "single-DES"; break;
2350 }
2351 if (s->supported_ciphers_mask & (1 << s->cipher_type))
2352 cipher_chosen = 1;
2353 }
2354 }
2355 if (!cipher_chosen) {
2356 if ((s->supported_ciphers_mask & (1 << SSH_CIPHER_3DES)) == 0)
2357 bombout((ssh,"Server violates SSH 1 protocol by not "
2358 "supporting 3DES encryption"));
2359 else
2360 /* shouldn't happen */
2361 bombout((ssh,"No supported ciphers found"));
2362 crReturn(0);
2363 }
2364
2365 /* Warn about chosen cipher if necessary. */
2366 if (warn)
2367 askcipher(ssh->frontend, cipher_string, 0);
2368 }
2369
2370 switch (s->cipher_type) {
2371 case SSH_CIPHER_3DES:
2372 logevent("Using 3DES encryption");
2373 break;
2374 case SSH_CIPHER_DES:
2375 logevent("Using single-DES encryption");
2376 break;
2377 case SSH_CIPHER_BLOWFISH:
2378 logevent("Using Blowfish encryption");
2379 break;
2380 }
2381
2382 send_packet(ssh, SSH1_CMSG_SESSION_KEY,
2383 PKT_CHAR, s->cipher_type,
2384 PKT_DATA, cookie, 8,
2385 PKT_CHAR, (s->len * 8) >> 8, PKT_CHAR, (s->len * 8) & 0xFF,
2386 PKT_DATA, s->rsabuf, s->len,
2387 PKT_INT, ssh->v1_local_protoflags, PKT_END);
2388
2389 logevent("Trying to enable encryption...");
2390
2391 sfree(s->rsabuf);
2392
2393 ssh->cipher = (s->cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 :
2394 s->cipher_type == SSH_CIPHER_DES ? &ssh_des :
2395 &ssh_3des);
2396 ssh->v1_cipher_ctx = ssh->cipher->make_context();
2397 ssh->cipher->sesskey(ssh->v1_cipher_ctx, ssh->session_key);
2398 logeventf(ssh, "Initialised %s encryption", ssh->cipher->text_name);
2399
2400 ssh->crcda_ctx = crcda_make_context();
2401 logevent("Installing CRC compensation attack detector");
2402
2403 crWaitUntil(ispkt);
2404
2405 if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
2406 bombout((ssh,"Encryption not successfully enabled"));
2407 crReturn(0);
2408 }
2409
2410 logevent("Successfully started encryption");
2411
2412 fflush(stdout);
2413 {
2414 if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
2415 if (ssh_get_line && !ssh_getline_pw_only) {
2416 if (!ssh_get_line("login as: ",
2417 s->username, sizeof(s->username), FALSE)) {
2418 /*
2419 * get_line failed to get a username.
2420 * Terminate.
2421 */
2422 logevent("No username provided. Abandoning session.");
2423 ssh->state = SSH_STATE_CLOSED;
2424 crReturn(1);
2425 }
2426 } else {
2427 int ret; /* need not be kept over crReturn */
2428 c_write_str(ssh, "login as: ");
2429 ssh->send_ok = 1;
2430
2431 setup_userpass_input(ssh, s->username, sizeof(s->username), 1);
2432 do {
2433 crWaitUntil(!ispkt);
2434 ret = process_userpass_input(ssh, in, inlen);
2435 } while (ret == 0);
2436 if (ret < 0)
2437 cleanup_exit(0);
2438 c_write_str(ssh, "\r\n");
2439 }
2440 } else {
2441 strncpy(s->username, cfg.username, sizeof(s->username));
2442 s->username[sizeof(s->username)-1] = '\0';
2443 }
2444
2445 send_packet(ssh, SSH1_CMSG_USER, PKT_STR, s->username, PKT_END);
2446 {
2447 char userlog[22 + sizeof(s->username)];
2448 sprintf(userlog, "Sent username \"%s\"", s->username);
2449 logevent(userlog);
2450 if (flags & FLAG_INTERACTIVE &&
2451 (!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) {
2452 strcat(userlog, "\r\n");
2453 c_write_str(ssh, userlog);
2454 }
2455 }
2456 }
2457
2458 crWaitUntil(ispkt);
2459
2460 if ((ssh->remote_bugs & BUG_CHOKES_ON_RSA)) {
2461 /* We must not attempt PK auth. Pretend we've already tried it. */
2462 s->tried_publickey = s->tried_agent = 1;
2463 } else {
2464 s->tried_publickey = s->tried_agent = 0;
2465 }
2466 s->tis_auth_refused = s->ccard_auth_refused = 0;
2467 /* Load the public half of cfg.keyfile so we notice if it's in Pageant */
2468 if (*cfg.keyfile) {
2469 if (!rsakey_pubblob(cfg.keyfile,
2470 &s->publickey_blob, &s->publickey_bloblen))
2471 s->publickey_blob = NULL;
2472 } else
2473 s->publickey_blob = NULL;
2474
2475 while (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2476 s->pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
2477
2478 if (agent_exists() && !s->tried_agent) {
2479 /*
2480 * Attempt RSA authentication using Pageant.
2481 */
2482 void *r;
2483
2484 s->authed = FALSE;
2485 s->tried_agent = 1;
2486 logevent("Pageant is running. Requesting keys.");
2487
2488 /* Request the keys held by the agent. */
2489 PUT_32BIT(s->request, 1);
2490 s->request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES;
2491 agent_query(s->request, 5, &r, &s->responselen);
2492 s->response = (unsigned char *) r;
2493 if (s->response && s->responselen >= 5 &&
2494 s->response[4] == SSH1_AGENT_RSA_IDENTITIES_ANSWER) {
2495 s->p = s->response + 5;
2496 s->nkeys = GET_32BIT(s->p);
2497 s->p += 4;
2498 {
2499 char buf[64];
2500 sprintf(buf, "Pageant has %d SSH1 keys", s->nkeys);
2501 logevent(buf);
2502 }
2503 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
2504 {
2505 char buf[64];
2506 sprintf(buf, "Trying Pageant key #%d", s->keyi);
2507 logevent(buf);
2508 }
2509 if (s->publickey_blob &&
2510 !memcmp(s->p, s->publickey_blob,
2511 s->publickey_bloblen)) {
2512 logevent("This key matches configured key file");
2513 s->tried_publickey = 1;
2514 }
2515 s->p += 4;
2516 s->p += ssh1_read_bignum(s->p, &s->key.exponent);
2517 s->p += ssh1_read_bignum(s->p, &s->key.modulus);
2518 s->commentlen = GET_32BIT(s->p);
2519 s->p += 4;
2520 s->commentp = (char *)s->p;
2521 s->p += s->commentlen;
2522 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
2523 PKT_BIGNUM, s->key.modulus, PKT_END);
2524 crWaitUntil(ispkt);
2525 if (ssh->pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
2526 logevent("Key refused");
2527 continue;
2528 }
2529 logevent("Received RSA challenge");
2530 ssh1_read_bignum(ssh->pktin.body, &s->challenge);
2531 {
2532 char *agentreq, *q, *ret;
2533 void *vret;
2534 int len, retlen;
2535 len = 1 + 4; /* message type, bit count */
2536 len += ssh1_bignum_length(s->key.exponent);
2537 len += ssh1_bignum_length(s->key.modulus);
2538 len += ssh1_bignum_length(s->challenge);
2539 len += 16; /* session id */
2540 len += 4; /* response format */
2541 agentreq = smalloc(4 + len);
2542 PUT_32BIT(agentreq, len);
2543 q = agentreq + 4;
2544 *q++ = SSH1_AGENTC_RSA_CHALLENGE;
2545 PUT_32BIT(q, bignum_bitcount(s->key.modulus));
2546 q += 4;
2547 q += ssh1_write_bignum(q, s->key.exponent);
2548 q += ssh1_write_bignum(q, s->key.modulus);
2549 q += ssh1_write_bignum(q, s->challenge);
2550 memcpy(q, s->session_id, 16);
2551 q += 16;
2552 PUT_32BIT(q, 1); /* response format */
2553 agent_query(agentreq, len + 4, &vret, &retlen);
2554 ret = vret;
2555 sfree(agentreq);
2556 if (ret) {
2557 if (ret[4] == SSH1_AGENT_RSA_RESPONSE) {
2558 logevent("Sending Pageant's response");
2559 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
2560 PKT_DATA, ret + 5, 16,
2561 PKT_END);
2562 sfree(ret);
2563 crWaitUntil(ispkt);
2564 if (ssh->pktin.type == SSH1_SMSG_SUCCESS) {
2565 logevent
2566 ("Pageant's response accepted");
2567 if (flags & FLAG_VERBOSE) {
2568 c_write_str(ssh, "Authenticated using"
2569 " RSA key \"");
2570 c_write(ssh, s->commentp,
2571 s->commentlen);
2572 c_write_str(ssh, "\" from agent\r\n");
2573 }
2574 s->authed = TRUE;
2575 } else
2576 logevent
2577 ("Pageant's response not accepted");
2578 } else {
2579 logevent
2580 ("Pageant failed to answer challenge");
2581 sfree(ret);
2582 }
2583 } else {
2584 logevent("No reply received from Pageant");
2585 }
2586 }
2587 freebn(s->key.exponent);
2588 freebn(s->key.modulus);
2589 freebn(s->challenge);
2590 if (s->authed)
2591 break;
2592 }
2593 }
2594 if (s->authed)
2595 break;
2596 }
2597 if (*cfg.keyfile && !s->tried_publickey)
2598 s->pwpkt_type = SSH1_CMSG_AUTH_RSA;
2599
2600 if (cfg.try_tis_auth &&
2601 (s->supported_auths_mask & (1 << SSH1_AUTH_TIS)) &&
2602 !s->tis_auth_refused) {
2603 s->pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
2604 logevent("Requested TIS authentication");
2605 send_packet(ssh, SSH1_CMSG_AUTH_TIS, PKT_END);
2606 crWaitUntil(ispkt);
2607 if (ssh->pktin.type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
2608 logevent("TIS authentication declined");
2609 if (flags & FLAG_INTERACTIVE)
2610 c_write_str(ssh, "TIS authentication refused.\r\n");
2611 s->tis_auth_refused = 1;
2612 continue;
2613 } else {
2614 int challengelen = GET_32BIT(ssh->pktin.body);
2615 logevent("Received TIS challenge");
2616 if (challengelen > sizeof(s->prompt) - 1)
2617 challengelen = sizeof(s->prompt) - 1;/* prevent overrun */
2618 memcpy(s->prompt, ssh->pktin.body + 4, challengelen);
2619 /* Prompt heuristic comes from OpenSSH */
2620 strncpy(s->prompt + challengelen,
2621 memchr(s->prompt, '\n', challengelen) ?
2622 "": "\r\nResponse: ",
2623 (sizeof s->prompt) - challengelen);
2624 s->prompt[(sizeof s->prompt) - 1] = '\0';
2625 }
2626 }
2627 if (cfg.try_tis_auth &&
2628 (s->supported_auths_mask & (1 << SSH1_AUTH_CCARD)) &&
2629 !s->ccard_auth_refused) {
2630 s->pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE;
2631 logevent("Requested CryptoCard authentication");
2632 send_packet(ssh, SSH1_CMSG_AUTH_CCARD, PKT_END);
2633 crWaitUntil(ispkt);
2634 if (ssh->pktin.type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
2635 logevent("CryptoCard authentication declined");
2636 c_write_str(ssh, "CryptoCard authentication refused.\r\n");
2637 s->ccard_auth_refused = 1;
2638 continue;
2639 } else {
2640 int challengelen = GET_32BIT(ssh->pktin.body);
2641 logevent("Received CryptoCard challenge");
2642 if (challengelen > sizeof(s->prompt) - 1)
2643 challengelen = sizeof(s->prompt) - 1;/* prevent overrun */
2644 memcpy(s->prompt, ssh->pktin.body + 4, challengelen);
2645 strncpy(s->prompt + challengelen,
2646 memchr(s->prompt, '\n', challengelen) ?
2647 "" : "\r\nResponse: ",
2648 sizeof(s->prompt) - challengelen);
2649 s->prompt[sizeof(s->prompt) - 1] = '\0';
2650 }
2651 }
2652 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
2653 sprintf(s->prompt, "%.90s@%.90s's password: ",
2654 s->username, ssh->savedhost);
2655 }
2656 if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) {
2657 char *comment = NULL;
2658 int type;
2659 char msgbuf[256];
2660 if (flags & FLAG_VERBOSE)
2661 c_write_str(ssh, "Trying public key authentication.\r\n");
2662 logeventf(ssh, "Trying public key \"%s\"", cfg.keyfile);
2663 type = key_type(cfg.keyfile);
2664 if (type != SSH_KEYTYPE_SSH1) {
2665 sprintf(msgbuf, "Key is of wrong type (%s)",
2666 key_type_to_str(type));
2667 logevent(msgbuf);
2668 c_write_str(ssh, msgbuf);
2669 c_write_str(ssh, "\r\n");
2670 s->tried_publickey = 1;
2671 continue;
2672 }
2673 if (!rsakey_encrypted(cfg.keyfile, &comment)) {
2674 if (flags & FLAG_VERBOSE)
2675 c_write_str(ssh, "No passphrase required.\r\n");
2676 goto tryauth;
2677 }
2678 sprintf(s->prompt, "Passphrase for key \"%.100s\": ", comment);
2679 sfree(comment);
2680 }
2681
2682 /*
2683 * Show password prompt, having first obtained it via a TIS
2684 * or CryptoCard exchange if we're doing TIS or CryptoCard
2685 * authentication.
2686 */
2687 if (ssh_get_line) {
2688 if (!ssh_get_line(s->prompt, s->password,
2689 sizeof(s->password), TRUE)) {
2690 /*
2691 * get_line failed to get a password (for example
2692 * because one was supplied on the command line
2693 * which has already failed to work). Terminate.
2694 */
2695 send_packet(ssh, SSH1_MSG_DISCONNECT,
2696 PKT_STR, "No more passwords available to try",
2697 PKT_END);
2698 logevent("Unable to authenticate");
2699 connection_fatal(ssh->frontend, "Unable to authenticate");
2700 ssh->state = SSH_STATE_CLOSED;
2701 crReturn(1);
2702 }
2703 } else {
2704 /* Prompt may have come from server. We've munged it a bit, so
2705 * we know it to be zero-terminated at least once. */
2706 int ret; /* need not be saved over crReturn */
2707 c_write_untrusted(ssh, s->prompt, strlen(s->prompt));
2708 s->pos = 0;
2709
2710 setup_userpass_input(ssh, s->password, sizeof(s->password), 0);
2711 do {
2712 crWaitUntil(!ispkt);
2713 ret = process_userpass_input(ssh, in, inlen);
2714 } while (ret == 0);
2715 if (ret < 0)
2716 cleanup_exit(0);
2717 c_write_str(ssh, "\r\n");
2718 }
2719
2720 tryauth:
2721 if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) {
2722 /*
2723 * Try public key authentication with the specified
2724 * key file.
2725 */
2726 s->tried_publickey = 1;
2727
2728 {
2729 int ret = loadrsakey(cfg.keyfile, &s->key, s->password);
2730 if (ret == 0) {
2731 c_write_str(ssh, "Couldn't load private key from ");
2732 c_write_str(ssh, cfg.keyfile);
2733 c_write_str(ssh, ".\r\n");
2734 continue; /* go and try password */
2735 }
2736 if (ret == -1) {
2737 c_write_str(ssh, "Wrong passphrase.\r\n");
2738 s->tried_publickey = 0;
2739 continue; /* try again */
2740 }
2741 }
2742
2743 /*
2744 * Send a public key attempt.
2745 */
2746 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
2747 PKT_BIGNUM, s->key.modulus, PKT_END);
2748
2749 crWaitUntil(ispkt);
2750 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2751 c_write_str(ssh, "Server refused our public key.\r\n");
2752 continue; /* go and try password */
2753 }
2754 if (ssh->pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
2755 bombout((ssh,"Bizarre response to offer of public key"));
2756 crReturn(0);
2757 }
2758
2759 {
2760 int i;
2761 unsigned char buffer[32];
2762 Bignum challenge, response;
2763
2764 ssh1_read_bignum(ssh->pktin.body, &challenge);
2765 response = rsadecrypt(challenge, &s->key);
2766 freebn(s->key.private_exponent);/* burn the evidence */
2767
2768 for (i = 0; i < 32; i++) {
2769 buffer[i] = bignum_byte(response, 31 - i);
2770 }
2771
2772 MD5Init(&md5c);
2773 MD5Update(&md5c, buffer, 32);
2774 MD5Update(&md5c, s->session_id, 16);
2775 MD5Final(buffer, &md5c);
2776
2777 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
2778 PKT_DATA, buffer, 16, PKT_END);
2779
2780 freebn(challenge);
2781 freebn(response);
2782 }
2783
2784 crWaitUntil(ispkt);
2785 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2786 if (flags & FLAG_VERBOSE)
2787 c_write_str(ssh, "Failed to authenticate with"
2788 " our public key.\r\n");
2789 continue; /* go and try password */
2790 } else if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
2791 bombout((ssh,"Bizarre response to RSA authentication response"));
2792 crReturn(0);
2793 }
2794
2795 break; /* we're through! */
2796 } else {
2797 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
2798 /*
2799 * Defence against traffic analysis: we send a
2800 * whole bunch of packets containing strings of
2801 * different lengths. One of these strings is the
2802 * password, in a SSH1_CMSG_AUTH_PASSWORD packet.
2803 * The others are all random data in
2804 * SSH1_MSG_IGNORE packets. This way a passive
2805 * listener can't tell which is the password, and
2806 * hence can't deduce the password length.
2807 *
2808 * Anybody with a password length greater than 16
2809 * bytes is going to have enough entropy in their
2810 * password that a listener won't find it _that_
2811 * much help to know how long it is. So what we'll
2812 * do is:
2813 *
2814 * - if password length < 16, we send 15 packets
2815 * containing string lengths 1 through 15
2816 *
2817 * - otherwise, we let N be the nearest multiple
2818 * of 8 below the password length, and send 8
2819 * packets containing string lengths N through
2820 * N+7. This won't obscure the order of
2821 * magnitude of the password length, but it will
2822 * introduce a bit of extra uncertainty.
2823 *
2824 * A few servers (the old 1.2.18 through 1.2.22)
2825 * can't deal with SSH1_MSG_IGNORE. For these
2826 * servers, we need an alternative defence. We make
2827 * use of the fact that the password is interpreted
2828 * as a C string: so we can append a NUL, then some
2829 * random data.
2830 *
2831 * One server (a Cisco one) can deal with neither
2832 * SSH1_MSG_IGNORE _nor_ a padded password string.
2833 * For this server we are left with no defences
2834 * against password length sniffing.
2835 */
2836 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE)) {
2837 /*
2838 * The server can deal with SSH1_MSG_IGNORE, so
2839 * we can use the primary defence.
2840 */
2841 int bottom, top, pwlen, i;
2842 char *randomstr;
2843
2844 pwlen = strlen(s->password);
2845 if (pwlen < 16) {
2846 bottom = 0; /* zero length passwords are OK! :-) */
2847 top = 15;
2848 } else {
2849 bottom = pwlen & ~7;
2850 top = bottom + 7;
2851 }
2852
2853 assert(pwlen >= bottom && pwlen <= top);
2854
2855 randomstr = smalloc(top + 1);
2856
2857 for (i = bottom; i <= top; i++) {
2858 if (i == pwlen)
2859 defer_packet(ssh, s->pwpkt_type,
2860 PKT_STR, s->password, PKT_END);
2861 else {
2862 for (j = 0; j < i; j++) {
2863 do {
2864 randomstr[j] = random_byte();
2865 } while (randomstr[j] == '\0');
2866 }
2867 randomstr[i] = '\0';
2868 defer_packet(ssh, SSH1_MSG_IGNORE,
2869 PKT_STR, randomstr, PKT_END);
2870 }
2871 }
2872 logevent("Sending password with camouflage packets");
2873 ssh_pkt_defersend(ssh);
2874 }
2875 else if (!(ssh->remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) {
2876 /*
2877 * The server can't deal with SSH1_MSG_IGNORE
2878 * but can deal with padded passwords, so we
2879 * can use the secondary defence.
2880 */
2881 char string[64];
2882 char *ss;
2883 int len;
2884
2885 len = strlen(s->password);
2886 if (len < sizeof(string)) {
2887 ss = string;
2888 strcpy(string, s->password);
2889 len++; /* cover the zero byte */
2890 while (len < sizeof(string)) {
2891 string[len++] = (char) random_byte();
2892 }
2893 } else {
2894 ss = s->password;
2895 }
2896 logevent("Sending length-padded password");
2897 send_packet(ssh, s->pwpkt_type, PKT_INT, len,
2898 PKT_DATA, ss, len, PKT_END);
2899 } else {
2900 /*
2901 * The server has _both_
2902 * BUG_CHOKES_ON_SSH1_IGNORE and
2903 * BUG_NEEDS_SSH1_PLAIN_PASSWORD. There is
2904 * therefore nothing we can do.
2905 */
2906 int len;
2907 len = strlen(s->password);
2908 logevent("Sending unpadded password");
2909 send_packet(ssh, s->pwpkt_type, PKT_INT, len,
2910 PKT_DATA, s->password, len, PKT_END);
2911 }
2912 } else {
2913 send_packet(ssh, s->pwpkt_type, PKT_STR, s->password, PKT_END);
2914 }
2915 }
2916 logevent("Sent password");
2917 memset(s->password, 0, strlen(s->password));
2918 crWaitUntil(ispkt);
2919 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2920 if (flags & FLAG_VERBOSE)
2921 c_write_str(ssh, "Access denied\r\n");
2922 logevent("Authentication refused");
2923 } else if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
2924 bombout((ssh,"Strange packet received, type %d", ssh->pktin.type));
2925 crReturn(0);
2926 }
2927 }
2928
2929 logevent("Authentication successful");
2930
2931 crFinish(1);
2932 }
2933
2934 void sshfwd_close(struct ssh_channel *c)
2935 {
2936 Ssh ssh = c->ssh;
2937
2938 if (c && !c->closes) {
2939 /*
2940 * If the channel's remoteid is -1, we have sent
2941 * CHANNEL_OPEN for this channel, but it hasn't even been
2942 * acknowledged by the server. So we must set a close flag
2943 * on it now, and then when the server acks the channel
2944 * open, we can close it then.
2945 */
2946 if (((int)c->remoteid) != -1) {
2947 if (ssh->version == 1) {
2948 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid,
2949 PKT_END);
2950 } else {
2951 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
2952 ssh2_pkt_adduint32(ssh, c->remoteid);
2953 ssh2_pkt_send(ssh);
2954 }
2955 }
2956 c->closes = 1; /* sent MSG_CLOSE */
2957 if (c->type == CHAN_X11) {
2958 c->u.x11.s = NULL;
2959 logevent("Forwarded X11 connection terminated");
2960 } else if (c->type == CHAN_SOCKDATA ||
2961 c->type == CHAN_SOCKDATA_DORMANT) {
2962 c->u.pfd.s = NULL;
2963 logevent("Forwarded port closed");
2964 }
2965 }
2966 }
2967
2968 int sshfwd_write(struct ssh_channel *c, char *buf, int len)
2969 {
2970 Ssh ssh = c->ssh;
2971
2972 if (ssh->version == 1) {
2973 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
2974 PKT_INT, c->remoteid,
2975 PKT_INT, len, PKT_DATA, buf, len, PKT_END);
2976 /*
2977 * In SSH1 we can return 0 here - implying that forwarded
2978 * connections are never individually throttled - because
2979 * the only circumstance that can cause throttling will be
2980 * the whole SSH connection backing up, in which case
2981 * _everything_ will be throttled as a whole.
2982 */
2983 return 0;
2984 } else {
2985 ssh2_add_channel_data(c, buf, len);
2986 return ssh2_try_send(c);
2987 }
2988 }
2989
2990 void sshfwd_unthrottle(struct ssh_channel *c, int bufsize)
2991 {
2992 Ssh ssh = c->ssh;
2993
2994 if (ssh->version == 1) {
2995 if (c->v.v1.throttling && bufsize < SSH1_BUFFER_LIMIT) {
2996 c->v.v1.throttling = 0;
2997 ssh1_throttle(ssh, -1);
2998 }
2999 } else {
3000 ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
3001 }
3002 }
3003
3004 static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
3005 {
3006 crBegin(ssh->ssh1_protocol_crstate);
3007
3008 random_init();
3009
3010 while (!do_ssh1_login(ssh, in, inlen, ispkt)) {
3011 crReturnV;
3012 }
3013 if (ssh->state == SSH_STATE_CLOSED)
3014 crReturnV;
3015
3016 if (cfg.agentfwd && agent_exists()) {
3017 logevent("Requesting agent forwarding");
3018 send_packet(ssh, SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END);
3019 do {
3020 crReturnV;
3021 } while (!ispkt);
3022 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3023 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3024 bombout((ssh,"Protocol confusion"));
3025 crReturnV;
3026 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3027 logevent("Agent forwarding refused");
3028 } else {
3029 logevent("Agent forwarding enabled");
3030 ssh->agentfwd_enabled = TRUE;
3031 }
3032 }
3033
3034 if (cfg.x11_forward) {
3035 char proto[20], data[64];
3036 logevent("Requesting X11 forwarding");
3037 ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
3038 data, sizeof(data));
3039 if (ssh->v1_local_protoflags & SSH1_PROTOFLAG_SCREEN_NUMBER) {
3040 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
3041 PKT_STR, proto, PKT_STR, data,
3042 PKT_INT, x11_get_screen_number(cfg.x11_display),
3043 PKT_END);
3044 } else {
3045 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
3046 PKT_STR, proto, PKT_STR, data, PKT_END);
3047 }
3048 do {
3049 crReturnV;
3050 } while (!ispkt);
3051 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3052 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3053 bombout((ssh,"Protocol confusion"));
3054 crReturnV;
3055 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3056 logevent("X11 forwarding refused");
3057 } else {
3058 logevent("X11 forwarding enabled");
3059 ssh->X11_fwd_enabled = TRUE;
3060 }
3061 }
3062
3063 {
3064 char type;
3065 int n;
3066 int sport,dport,sserv,dserv;
3067 char sports[256], dports[256], saddr[256], host[256];
3068
3069 ssh->rportfwds = newtree234(ssh_rportcmp_ssh1);
3070 /* Add port forwardings. */
3071 ssh->portfwd_strptr = cfg.portfwd;
3072 while (*ssh->portfwd_strptr) {
3073 type = *ssh->portfwd_strptr++;
3074 saddr[0] = '\0';
3075 n = 0;
3076 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != '\t') {
3077 if (*ssh->portfwd_strptr == ':') {
3078 /*
3079 * We've seen a colon in the middle of the
3080 * source port number. This means that
3081 * everything we've seen until now is the
3082 * source _address_, so we'll move it into
3083 * saddr and start sports from the beginning
3084 * again.
3085 */
3086 ssh->portfwd_strptr++;
3087 sports[n] = '\0';
3088 strcpy(saddr, sports);
3089 n = 0;
3090 }
3091 if (n < 255) sports[n++] = *ssh->portfwd_strptr++;
3092 }
3093 sports[n] = 0;
3094 if (*ssh->portfwd_strptr == '\t')
3095 ssh->portfwd_strptr++;
3096 n = 0;
3097 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':') {
3098 if (n < 255) host[n++] = *ssh->portfwd_strptr++;
3099 }
3100 host[n] = 0;
3101 if (*ssh->portfwd_strptr == ':')
3102 ssh->portfwd_strptr++;
3103 n = 0;
3104 while (*ssh->portfwd_strptr) {
3105 if (n < 255) dports[n++] = *ssh->portfwd_strptr++;
3106 }
3107 dports[n] = 0;
3108 ssh->portfwd_strptr++;
3109 dport = atoi(dports);
3110 dserv = 0;
3111 if (dport == 0) {
3112 dserv = 1;
3113 dport = net_service_lookup(dports);
3114 if (!dport) {
3115 logeventf(ssh, "Service lookup failed for"
3116 " destination port \"%s\"", dports);
3117 }
3118 }
3119 sport = atoi(sports);
3120 sserv = 0;
3121 if (sport == 0) {
3122 sserv = 1;
3123 sport = net_service_lookup(sports);
3124 if (!sport) {
3125 logeventf(ssh, "Service lookup failed for source"
3126 " port \"%s\"", sports);
3127 }
3128 }
3129 if (sport && dport) {
3130 if (type == 'L') {
3131 pfd_addforward(host, dport, *saddr ? saddr : NULL,
3132 sport, ssh);
3133 logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
3134 " forwarding to %s:%.*s%.*s%d%.*s",
3135 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
3136 (int)(*saddr?1:0), ":",
3137 (int)(sserv ? strlen(sports) : 0), sports,
3138 sserv, "(", sport, sserv, ")",
3139 host,
3140 (int)(dserv ? strlen(dports) : 0), dports,
3141 dserv, "(", dport, dserv, ")");
3142 } else {
3143 struct ssh_rportfwd *pf;
3144 pf = smalloc(sizeof(*pf));
3145 strcpy(pf->dhost, host);
3146 pf->dport = dport;
3147 if (saddr) {
3148 logeventf(ssh,
3149 "SSH1 cannot handle source address spec \"%s:%d\"; ignoring",
3150 saddr, sport);
3151 }
3152 if (add234(ssh->rportfwds, pf) != pf) {
3153 logeventf(ssh,
3154 "Duplicate remote port forwarding to %s:%d",
3155 host, dport);
3156 sfree(pf);
3157 } else {
3158 logeventf(ssh, "Requesting remote port %.*s%.*s%d%.*s"
3159 " forward to %s:%.*s%.*s%d%.*s",
3160 (int)(sserv ? strlen(sports) : 0), sports,
3161 sserv, "(", sport, sserv, ")",
3162 host,
3163 (int)(dserv ? strlen(dports) : 0), dports,
3164 dserv, "(", dport, dserv, ")");
3165 send_packet(ssh, SSH1_CMSG_PORT_FORWARD_REQUEST,
3166 PKT_INT, sport,
3167 PKT_STR, host,
3168 PKT_INT, dport,
3169 PKT_END);
3170 do {
3171 crReturnV;
3172 } while (!ispkt);
3173 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3174 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3175 bombout((ssh,"Protocol confusion"));
3176 crReturnV;
3177 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3178 c_write_str(ssh, "Server refused port"
3179 " forwarding\r\n");
3180 }
3181 logevent("Remote port forwarding enabled");
3182 }
3183 }
3184 }
3185 }
3186 }
3187
3188 if (!cfg.nopty) {
3189 send_packet(ssh, SSH1_CMSG_REQUEST_PTY,
3190 PKT_STR, cfg.termtype,
3191 PKT_INT, ssh->term_height,
3192 PKT_INT, ssh->term_width,
3193 PKT_INT, 0, PKT_INT, 0, PKT_CHAR, 0, PKT_END);
3194 ssh->state = SSH_STATE_INTERMED;
3195 do {
3196 crReturnV;
3197 } while (!ispkt);
3198 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3199 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3200 bombout((ssh,"Protocol confusion"));
3201 crReturnV;
3202 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3203 c_write_str(ssh, "Server refused to allocate pty\r\n");
3204 ssh->editing = ssh->echoing = 1;
3205 }
3206 logevent("Allocated pty");
3207 } else {
3208 ssh->editing = ssh->echoing = 1;
3209 }
3210
3211 if (cfg.compression) {
3212 send_packet(ssh, SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END);
3213 do {
3214 crReturnV;
3215 } while (!ispkt);
3216 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3217 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3218 bombout((ssh,"Protocol confusion"));
3219 crReturnV;
3220 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3221 c_write_str(ssh, "Server refused to compress\r\n");
3222 }
3223 logevent("Started compression");
3224 ssh->v1_compressing = TRUE;
3225 ssh->cs_comp_ctx = zlib_compress_init();
3226 logevent("Initialised zlib (RFC1950) compression");
3227 ssh->sc_comp_ctx = zlib_decompress_init();
3228 logevent("Initialised zlib (RFC1950) decompression");
3229 }
3230
3231 /*
3232 * Start the shell or command.
3233 *
3234 * Special case: if the first-choice command is an SSH2
3235 * subsystem (hence not usable here) and the second choice
3236 * exists, we fall straight back to that.
3237 */
3238 {
3239 char *cmd = cfg.remote_cmd_ptr;
3240
3241 if (cfg.ssh_subsys && cfg.remote_cmd_ptr2) {
3242 cmd = cfg.remote_cmd_ptr2;
3243 ssh->fallback_cmd = TRUE;
3244 }
3245 if (*cmd)
3246 send_packet(ssh, SSH1_CMSG_EXEC_CMD, PKT_STR, cmd, PKT_END);
3247 else
3248 send_packet(ssh, SSH1_CMSG_EXEC_SHELL, PKT_END);
3249 logevent("Started session");
3250 }
3251
3252 ssh->state = SSH_STATE_SESSION;
3253 if (ssh->size_needed)
3254 ssh_size(ssh, ssh->term_width, ssh->term_height);
3255 if (ssh->eof_needed)
3256 ssh_special(ssh, TS_EOF);
3257
3258 if (ssh->ldisc)
3259 ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */
3260 ssh->send_ok = 1;
3261 ssh->channels = newtree234(ssh_channelcmp);
3262 while (1) {
3263 crReturnV;
3264 if (ispkt) {
3265 if (ssh->pktin.type == SSH1_SMSG_STDOUT_DATA ||
3266 ssh->pktin.type == SSH1_SMSG_STDERR_DATA) {
3267 long len = GET_32BIT(ssh->pktin.body);
3268 int bufsize =
3269 from_backend(ssh->frontend,
3270 ssh->pktin.type == SSH1_SMSG_STDERR_DATA,
3271 (char *)(ssh->pktin.body) + 4, len);
3272 if (!ssh->v1_stdout_throttling && bufsize > SSH1_BUFFER_LIMIT) {
3273 ssh->v1_stdout_throttling = 1;
3274 ssh1_throttle(ssh, +1);
3275 }
3276 } else if (ssh->pktin.type == SSH1_MSG_DISCONNECT) {
3277 ssh->state = SSH_STATE_CLOSED;
3278 logevent("Received disconnect request");
3279 crReturnV;
3280 } else if (ssh->pktin.type == SSH1_SMSG_X11_OPEN) {
3281 /* Remote side is trying to open a channel to talk to our
3282 * X-Server. Give them back a local channel number. */
3283 struct ssh_channel *c;
3284
3285 logevent("Received X11 connect request");
3286 /* Refuse if X11 forwarding is disabled. */
3287 if (!ssh->X11_fwd_enabled) {
3288 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3289 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
3290 logevent("Rejected X11 connect request");
3291 } else {
3292 c = smalloc(sizeof(struct ssh_channel));
3293 c->ssh = ssh;
3294
3295 if (x11_init(&c->u.x11.s, cfg.x11_display, c,
3296 ssh->x11auth) != NULL) {
3297 logevent("opening X11 forward connection failed");
3298 sfree(c);
3299 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3300 PKT_INT, GET_32BIT(ssh->pktin.body),
3301 PKT_END);
3302 } else {
3303 logevent
3304 ("opening X11 forward connection succeeded");
3305 c->remoteid = GET_32BIT(ssh->pktin.body);
3306 c->localid = alloc_channel_id(ssh);
3307 c->closes = 0;
3308 c->v.v1.throttling = 0;
3309 c->type = CHAN_X11; /* identify channel type */
3310 add234(ssh->channels, c);
3311 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3312 PKT_INT, c->remoteid, PKT_INT,
3313 c->localid, PKT_END);
3314 logevent("Opened X11 forward channel");
3315 }
3316 }
3317 } else if (ssh->pktin.type == SSH1_SMSG_AGENT_OPEN) {
3318 /* Remote side is trying to open a channel to talk to our
3319 * agent. Give them back a local channel number. */
3320 struct ssh_channel *c;
3321
3322 /* Refuse if agent forwarding is disabled. */
3323 if (!ssh->agentfwd_enabled) {
3324 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3325 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
3326 } else {
3327 c = smalloc(sizeof(struct ssh_channel));
3328 c->ssh = ssh;
3329 c->remoteid = GET_32BIT(ssh->pktin.body);
3330 c->localid = alloc_channel_id(ssh);
3331 c->closes = 0;
3332 c->v.v1.throttling = 0;
3333 c->type = CHAN_AGENT; /* identify channel type */
3334 c->u.a.lensofar = 0;
3335 add234(ssh->channels, c);
3336 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3337 PKT_INT, c->remoteid, PKT_INT, c->localid,
3338 PKT_END);
3339 }
3340 } else if (ssh->pktin.type == SSH1_MSG_PORT_OPEN) {
3341 /* Remote side is trying to open a channel to talk to a
3342 * forwarded port. Give them back a local channel number. */
3343 struct ssh_channel *c;
3344 struct ssh_rportfwd pf;
3345 int hostsize, port;
3346 char host[256], buf[1024];
3347 char *p, *h, *e;
3348 c = smalloc(sizeof(struct ssh_channel));
3349 c->ssh = ssh;
3350
3351 hostsize = GET_32BIT(ssh->pktin.body+4);
3352 for (h = host, p = (char *)(ssh->pktin.body+8);
3353 hostsize != 0; hostsize--) {
3354 if (h+1 < host+sizeof(host))
3355 *h++ = *p;
3356 p++;
3357 }
3358 *h = 0;
3359 port = GET_32BIT(p);
3360
3361 strcpy(pf.dhost, host);
3362 pf.dport = port;
3363
3364 if (find234(ssh->rportfwds, &pf, NULL) == NULL) {
3365 sprintf(buf, "Rejected remote port open request for %s:%d",
3366 host, port);
3367 logevent(buf);
3368 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3369 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
3370 } else {
3371 sprintf(buf, "Received remote port open request for %s:%d",
3372 host, port);
3373 logevent(buf);
3374 e = pfd_newconnect(&c->u.pfd.s, host, port, c);
3375 if (e != NULL) {
3376 char buf[256];
3377 sprintf(buf, "Port open failed: %s", e);
3378 logevent(buf);
3379 sfree(c);
3380 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3381 PKT_INT, GET_32BIT(ssh->pktin.body),
3382 PKT_END);
3383 } else {
3384 c->remoteid = GET_32BIT(ssh->pktin.body);
3385 c->localid = alloc_channel_id(ssh);
3386 c->closes = 0;
3387 c->v.v1.throttling = 0;
3388 c->type = CHAN_SOCKDATA; /* identify channel type */
3389 add234(ssh->channels, c);
3390 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3391 PKT_INT, c->remoteid, PKT_INT,
3392 c->localid, PKT_END);
3393 logevent("Forwarded port opened successfully");
3394 }
3395 }
3396
3397 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_OPEN_CONFIRMATION) {
3398 unsigned int remoteid = GET_32BIT(ssh->pktin.body);
3399 unsigned int localid = GET_32BIT(ssh->pktin.body+4);
3400 struct ssh_channel *c;
3401
3402 c = find234(ssh->channels, &remoteid, ssh_channelfind);
3403 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
3404 c->remoteid = localid;
3405 c->type = CHAN_SOCKDATA;
3406 c->v.v1.throttling = 0;
3407 pfd_confirm(c->u.pfd.s);
3408 }
3409
3410 if (c && c->closes) {
3411 /*
3412 * We have a pending close on this channel,
3413 * which we decided on before the server acked
3414 * the channel open. So now we know the
3415 * remoteid, we can close it again.
3416 */
3417 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE,
3418 PKT_INT, c->remoteid, PKT_END);
3419 }
3420
3421 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_OPEN_FAILURE) {
3422 unsigned int remoteid = GET_32BIT(ssh->pktin.body);
3423 struct ssh_channel *c;
3424
3425 c = find234(ssh->channels, &remoteid, ssh_channelfind);
3426 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
3427 logevent("Forwarded connection refused by server");
3428 pfd_close(c->u.pfd.s);
3429 del234(ssh->channels, c);
3430 sfree(c);
3431 }
3432
3433 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ||
3434 ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION) {
3435 /* Remote side closes a channel. */
3436 unsigned i = GET_32BIT(ssh->pktin.body);
3437 struct ssh_channel *c;
3438 c = find234(ssh->channels, &i, ssh_channelfind);
3439 if (c && ((int)c->remoteid) != -1) {
3440 int closetype;
3441 closetype =
3442 (ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ? 1 : 2);
3443
3444 if ((c->closes == 0) && (c->type == CHAN_X11)) {
3445 logevent("Forwarded X11 connection terminated");
3446 assert(c->u.x11.s != NULL);
3447 x11_close(c->u.x11.s);
3448 c->u.x11.s = NULL;
3449 }
3450 if ((c->closes == 0) && (c->type == CHAN_SOCKDATA)) {
3451 logevent("Forwarded port closed");
3452 assert(c->u.pfd.s != NULL);
3453 pfd_close(c->u.pfd.s);
3454 c->u.pfd.s = NULL;
3455 }
3456
3457 c->closes |= (closetype << 2); /* seen this message */
3458 if (!(c->closes & closetype)) {
3459 send_packet(ssh, ssh->pktin.type, PKT_INT, c->remoteid,
3460 PKT_END);
3461 c->closes |= closetype; /* sent it too */
3462 }
3463
3464 if (c->closes == 15) {
3465 del234(ssh->channels, c);
3466 sfree(c);
3467 }
3468 } else {
3469 bombout((ssh,"Received CHANNEL_CLOSE%s for %s channel %d\n",
3470 ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ? "" :
3471 "_CONFIRMATION", c ? "half-open" : "nonexistent",
3472 i));
3473 }
3474 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_DATA) {
3475 /* Data sent down one of our channels. */
3476 int i = GET_32BIT(ssh->pktin.body);
3477 int len = GET_32BIT(ssh->pktin.body + 4);
3478 unsigned char *p = ssh->pktin.body + 8;
3479 struct ssh_channel *c;
3480 c = find234(ssh->channels, &i, ssh_channelfind);
3481 if (c) {
3482 int bufsize;
3483 switch (c->type) {
3484 case CHAN_X11:
3485 bufsize = x11_send(c->u.x11.s, (char *)p, len);
3486 break;
3487 case CHAN_SOCKDATA:
3488 bufsize = pfd_send(c->u.pfd.s, (char *)p, len);
3489 break;
3490 case CHAN_AGENT:
3491 /* Data for an agent message. Buffer it. */
3492 while (len > 0) {
3493 if (c->u.a.lensofar < 4) {
3494 int l = min(4 - c->u.a.lensofar, len);
3495 memcpy(c->u.a.msglen + 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 == 4) {
3502 c->u.a.totallen =
3503 4 + GET_32BIT(c->u.a.msglen);
3504 c->u.a.message = smalloc(c->u.a.totallen);
3505 memcpy(c->u.a.message, c->u.a.msglen, 4);
3506 }
3507 if (c->u.a.lensofar >= 4 && len > 0) {
3508 int l =
3509 min(c->u.a.totallen - c->u.a.lensofar,
3510 len);
3511 memcpy(c->u.a.message + c->u.a.lensofar, p,
3512 l);
3513 p += l;
3514 len -= l;
3515 c->u.a.lensofar += l;
3516 }
3517 if (c->u.a.lensofar == c->u.a.totallen) {
3518 void *reply, *sentreply;
3519 int replylen;
3520 agent_query(c->u.a.message,
3521 c->u.a.totallen, &reply,
3522 &replylen);
3523 if (reply)
3524 sentreply = reply;
3525 else {
3526 /* Fake SSH_AGENT_FAILURE. */
3527 sentreply = "\0\0\0\1\5";
3528 replylen = 5;
3529 }
3530 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
3531 PKT_INT, c->remoteid,
3532 PKT_INT, replylen,
3533 PKT_DATA, sentreply, replylen,
3534 PKT_END);
3535 if (reply)
3536 sfree(reply);
3537 sfree(c->u.a.message);
3538 c->u.a.lensofar = 0;
3539 }
3540 }
3541 bufsize = 0; /* agent channels never back up */
3542 break;
3543 }
3544 if (!c->v.v1.throttling && bufsize > SSH1_BUFFER_LIMIT) {
3545 c->v.v1.throttling = 1;
3546 ssh1_throttle(ssh, +1);
3547 }
3548 }
3549 } else if (ssh->pktin.type == SSH1_SMSG_SUCCESS) {
3550 /* may be from EXEC_SHELL on some servers */
3551 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3552 /* may be from EXEC_SHELL on some servers
3553 * if no pty is available or in other odd cases. Ignore */
3554 } else if (ssh->pktin.type == SSH1_SMSG_EXIT_STATUS) {
3555 char buf[100];
3556 ssh->exitcode = GET_32BIT(ssh->pktin.body);
3557 sprintf(buf, "Server sent command exit status %d",
3558 ssh->exitcode);
3559 logevent(buf);
3560 send_packet(ssh, SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
3561 /*
3562 * In case `helpful' firewalls or proxies tack
3563 * extra human-readable text on the end of the
3564 * session which we might mistake for another
3565 * encrypted packet, we close the session once
3566 * we've sent EXIT_CONFIRMATION.
3567 */
3568 ssh->state = SSH_STATE_CLOSED;
3569 crReturnV;
3570 } else {
3571 bombout((ssh,"Strange packet received: type %d", ssh->pktin.type));
3572 crReturnV;
3573 }
3574 } else {
3575 while (inlen > 0) {
3576 int len = min(inlen, 512);
3577 send_packet(ssh, SSH1_CMSG_STDIN_DATA,
3578 PKT_INT, len, PKT_DATA, in, len, PKT_END);
3579 in += len;
3580 inlen -= len;
3581 }
3582 }
3583 }
3584
3585 crFinishV;
3586 }
3587
3588 /*
3589 * Utility routine for decoding comma-separated strings in KEXINIT.
3590 */
3591 static int in_commasep_string(char *needle, char *haystack, int haylen)
3592 {
3593 int needlen;
3594 if (!needle || !haystack) /* protect against null pointers */
3595 return 0;
3596 needlen = strlen(needle);
3597 while (1) {
3598 /*
3599 * Is it at the start of the string?
3600 */
3601 if (haylen >= needlen && /* haystack is long enough */
3602 !memcmp(needle, haystack, needlen) && /* initial match */
3603 (haylen == needlen || haystack[needlen] == ',')
3604 /* either , or EOS follows */
3605 )
3606 return 1;
3607 /*
3608 * If not, search for the next comma and resume after that.
3609 * If no comma found, terminate.
3610 */
3611 while (haylen > 0 && *haystack != ',')
3612 haylen--, haystack++;
3613 if (haylen == 0)
3614 return 0;
3615 haylen--, haystack++; /* skip over comma itself */
3616 }
3617 }
3618
3619 /*
3620 * SSH2 key creation method.
3621 */
3622 static void ssh2_mkkey(Ssh ssh, Bignum K, unsigned char *H,
3623 unsigned char *sessid, char chr,
3624 unsigned char *keyspace)
3625 {
3626 SHA_State s;
3627 /* First 20 bytes. */
3628 SHA_Init(&s);
3629 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
3630 sha_mpint(&s, K);
3631 SHA_Bytes(&s, H, 20);
3632 SHA_Bytes(&s, &chr, 1);
3633 SHA_Bytes(&s, sessid, 20);
3634 SHA_Final(&s, keyspace);
3635 /* Next 20 bytes. */
3636 SHA_Init(&s);
3637 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
3638 sha_mpint(&s, K);
3639 SHA_Bytes(&s, H, 20);
3640 SHA_Bytes(&s, keyspace, 20);
3641 SHA_Final(&s, keyspace + 20);
3642 }
3643
3644 /*
3645 * Handle the SSH2 transport layer.
3646 */
3647 static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
3648 {
3649 struct do_ssh2_transport_state {
3650 int nbits, pbits, warn;
3651 Bignum p, g, e, f, K;
3652 int kex_init_value, kex_reply_value;
3653 const struct ssh_mac **maclist;
3654 int nmacs;
3655 const struct ssh2_cipher *cscipher_tobe;
3656 const struct ssh2_cipher *sccipher_tobe;
3657 const struct ssh_mac *csmac_tobe;
3658 const struct ssh_mac *scmac_tobe;
3659 const struct ssh_compress *cscomp_tobe;
3660 const struct ssh_compress *sccomp_tobe;
3661 char *hostkeydata, *sigdata, *keystr, *fingerprint;
3662 int hostkeylen, siglen;
3663 void *hkey; /* actual host key */
3664 unsigned char exchange_hash[20];
3665 int n_preferred_ciphers;
3666 const struct ssh2_ciphers *preferred_ciphers[CIPHER_MAX];
3667 const struct ssh_compress *preferred_comp;
3668 int first_kex;
3669 };
3670 crState(do_ssh2_transport_state);
3671
3672 crBegin(ssh->do_ssh2_transport_crstate);
3673
3674 s->cscipher_tobe = s->sccipher_tobe = NULL;
3675 s->csmac_tobe = s->scmac_tobe = NULL;
3676 s->cscomp_tobe = s->sccomp_tobe = NULL;
3677
3678 random_init();
3679 s->first_kex = 1;
3680
3681 {
3682 int i;
3683 /*
3684 * Set up the preferred ciphers. (NULL => warn below here)
3685 */
3686 s->n_preferred_ciphers = 0;
3687 for (i = 0; i < CIPHER_MAX; i++) {
3688 switch (cfg.ssh_cipherlist[i]) {
3689 case CIPHER_BLOWFISH:
3690 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_blowfish;
3691 break;
3692 case CIPHER_DES:
3693 if (cfg.ssh2_des_cbc) {
3694 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_des;
3695 }
3696 break;
3697 case CIPHER_3DES:
3698 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_3des;
3699 break;
3700 case CIPHER_AES:
3701 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_aes;
3702 break;
3703 case CIPHER_WARN:
3704 /* Flag for later. Don't bother if it's the last in
3705 * the list. */
3706 if (i < CIPHER_MAX - 1) {
3707 s->preferred_ciphers[s->n_preferred_ciphers++] = NULL;
3708 }
3709 break;
3710 }
3711 }
3712 }
3713
3714 /*
3715 * Set up preferred compression.
3716 */
3717 if (cfg.compression)
3718 s->preferred_comp = &ssh_zlib;
3719 else
3720 s->preferred_comp = &ssh_comp_none;
3721
3722 /*
3723 * Be prepared to work around the buggy MAC problem.
3724 */
3725 if (ssh->remote_bugs & BUG_SSH2_HMAC)
3726 s->maclist = buggymacs, s->nmacs = lenof(buggymacs);
3727 else
3728 s->maclist = macs, s->nmacs = lenof(macs);
3729
3730 begin_key_exchange:
3731 {
3732 int i, j, cipherstr_started;
3733
3734 /*
3735 * Construct and send our key exchange packet.
3736 */
3737 ssh2_pkt_init(ssh, SSH2_MSG_KEXINIT);
3738 for (i = 0; i < 16; i++)
3739 ssh2_pkt_addbyte(ssh, (unsigned char) random_byte());
3740 /* List key exchange algorithms. */
3741 ssh2_pkt_addstring_start(ssh);
3742 for (i = 0; i < lenof(kex_algs); i++) {
3743 if (kex_algs[i] == &ssh_diffiehellman_gex &&
3744 (ssh->remote_bugs & BUG_SSH2_DH_GEX))
3745 continue;
3746 ssh2_pkt_addstring_str(ssh, kex_algs[i]->name);
3747 if (i < lenof(kex_algs) - 1)
3748 ssh2_pkt_addstring_str(ssh, ",");
3749 }
3750 /* List server host key algorithms. */
3751 ssh2_pkt_addstring_start(ssh);
3752 for (i = 0; i < lenof(hostkey_algs); i++) {
3753 ssh2_pkt_addstring_str(ssh, hostkey_algs[i]->name);
3754 if (i < lenof(hostkey_algs) - 1)
3755 ssh2_pkt_addstring_str(ssh, ",");
3756 }
3757 /* List client->server encryption algorithms. */
3758 ssh2_pkt_addstring_start(ssh);
3759 cipherstr_started = 0;
3760 for (i = 0; i < s->n_preferred_ciphers; i++) {
3761 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3762 if (!c) continue; /* warning flag */
3763 for (j = 0; j < c->nciphers; j++) {
3764 if (cipherstr_started)
3765 ssh2_pkt_addstring_str(ssh, ",");
3766 ssh2_pkt_addstring_str(ssh, c->list[j]->name);
3767 cipherstr_started = 1;
3768 }
3769 }
3770 /* List server->client encryption algorithms. */
3771 ssh2_pkt_addstring_start(ssh);
3772 cipherstr_started = 0;
3773 for (i = 0; i < s->n_preferred_ciphers; i++) {
3774 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3775 if (!c) continue; /* warning flag */
3776 for (j = 0; j < c->nciphers; j++) {
3777 if (cipherstr_started)
3778 ssh2_pkt_addstring_str(ssh, ",");
3779 ssh2_pkt_addstring_str(ssh, c->list[j]->name);
3780 cipherstr_started = 1;
3781 }
3782 }
3783 /* List client->server MAC algorithms. */
3784 ssh2_pkt_addstring_start(ssh);
3785 for (i = 0; i < s->nmacs; i++) {
3786 ssh2_pkt_addstring_str(ssh, s->maclist[i]->name);
3787 if (i < s->nmacs - 1)
3788 ssh2_pkt_addstring_str(ssh, ",");
3789 }
3790 /* List server->client MAC algorithms. */
3791 ssh2_pkt_addstring_start(ssh);
3792 for (i = 0; i < s->nmacs; i++) {
3793 ssh2_pkt_addstring_str(ssh, s->maclist[i]->name);
3794 if (i < s->nmacs - 1)
3795 ssh2_pkt_addstring_str(ssh, ",");
3796 }
3797 /* List client->server compression algorithms. */
3798 ssh2_pkt_addstring_start(ssh);
3799 for (i = 0; i < lenof(compressions) + 1; i++) {
3800 const struct ssh_compress *c =
3801 i == 0 ? s->preferred_comp : compressions[i - 1];
3802 ssh2_pkt_addstring_str(ssh, c->name);
3803 if (i < lenof(compressions))
3804 ssh2_pkt_addstring_str(ssh, ",");
3805 }
3806 /* List server->client compression algorithms. */
3807 ssh2_pkt_addstring_start(ssh);
3808 for (i = 0; i < lenof(compressions) + 1; i++) {
3809 const struct ssh_compress *c =
3810 i == 0 ? s->preferred_comp : compressions[i - 1];
3811 ssh2_pkt_addstring_str(ssh, c->name);
3812 if (i < lenof(compressions))
3813 ssh2_pkt_addstring_str(ssh, ",");
3814 }
3815 /* List client->server languages. Empty list. */
3816 ssh2_pkt_addstring_start(ssh);
3817 /* List server->client languages. Empty list. */
3818 ssh2_pkt_addstring_start(ssh);
3819 /* First KEX packet does _not_ follow, because we're not that brave. */
3820 ssh2_pkt_addbool(ssh, FALSE);
3821 /* Reserved. */
3822 ssh2_pkt_adduint32(ssh, 0);
3823 }
3824
3825 ssh->exhash = ssh->exhashbase;
3826 sha_string(&ssh->exhash, ssh->pktout.data + 5, ssh->pktout.length - 5);
3827
3828 ssh2_pkt_send(ssh);
3829
3830 if (!ispkt)
3831 crWaitUntil(ispkt);
3832 if (ssh->pktin.length > 5)
3833 sha_string(&ssh->exhash, ssh->pktin.data + 5, ssh->pktin.length - 5);
3834
3835 /*
3836 * Now examine the other side's KEXINIT to see what we're up
3837 * to.
3838 */
3839 {
3840 char *str;
3841 int i, j, len;
3842
3843 if (ssh->pktin.type != SSH2_MSG_KEXINIT) {
3844 bombout((ssh,"expected key exchange packet from server"));
3845 crReturn(0);
3846 }
3847 ssh->kex = NULL;
3848 ssh->hostkey = NULL;
3849 s->cscipher_tobe = NULL;
3850 s->sccipher_tobe = NULL;
3851 s->csmac_tobe = NULL;
3852 s->scmac_tobe = NULL;
3853 s->cscomp_tobe = NULL;
3854 s->sccomp_tobe = NULL;
3855 ssh->pktin.savedpos += 16; /* skip garbage cookie */
3856 ssh2_pkt_getstring(ssh, &str, &len); /* key exchange algorithms */
3857 for (i = 0; i < lenof(kex_algs); i++) {
3858 if (kex_algs[i] == &ssh_diffiehellman_gex &&
3859 (ssh->remote_bugs & BUG_SSH2_DH_GEX))
3860 continue;
3861 if (in_commasep_string(kex_algs[i]->name, str, len)) {
3862 ssh->kex = kex_algs[i];
3863 break;
3864 }
3865 }
3866 ssh2_pkt_getstring(ssh, &str, &len); /* host key algorithms */
3867 for (i = 0; i < lenof(hostkey_algs); i++) {
3868 if (in_commasep_string(hostkey_algs[i]->name, str, len)) {
3869 ssh->hostkey = hostkey_algs[i];
3870 break;
3871 }
3872 }
3873 ssh2_pkt_getstring(ssh, &str, &len); /* client->server cipher */
3874 s->warn = 0;
3875 for (i = 0; i < s->n_preferred_ciphers; i++) {
3876 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3877 if (!c) {
3878 s->warn = 1;
3879 } else {
3880 for (j = 0; j < c->nciphers; j++) {
3881 if (in_commasep_string(c->list[j]->name, str, len)) {
3882 s->cscipher_tobe = c->list[j];
3883 break;
3884 }
3885 }
3886 }
3887 if (s->cscipher_tobe) {
3888 if (s->warn)
3889 askcipher(ssh->frontend, s->cscipher_tobe->name, 1);
3890 break;
3891 }
3892 }
3893 if (!s->cscipher_tobe) {
3894 bombout((ssh,"Couldn't agree a client-to-server cipher (available: %s)",
3895 str ? str : "(null)"));
3896 crReturn(0);
3897 }
3898
3899 ssh2_pkt_getstring(ssh, &str, &len); /* server->client cipher */
3900 s->warn = 0;
3901 for (i = 0; i < s->n_preferred_ciphers; i++) {
3902 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3903 if (!c) {
3904 s->warn = 1;
3905 } else {
3906 for (j = 0; j < c->nciphers; j++) {
3907 if (in_commasep_string(c->list[j]->name, str, len)) {
3908 s->sccipher_tobe = c->list[j];
3909 break;
3910 }
3911 }
3912 }
3913 if (s->sccipher_tobe) {
3914 if (s->warn)
3915 askcipher(ssh->frontend, s->sccipher_tobe->name, 2);
3916 break;
3917 }
3918 }
3919 if (!s->sccipher_tobe) {
3920 bombout((ssh,"Couldn't agree a server-to-client cipher (available: %s)",
3921 str ? str : "(null)"));
3922 crReturn(0);
3923 }
3924
3925 ssh2_pkt_getstring(ssh, &str, &len); /* client->server mac */
3926 for (i = 0; i < s->nmacs; i++) {
3927 if (in_commasep_string(s->maclist[i]->name, str, len)) {
3928 s->csmac_tobe = s->maclist[i];
3929 break;
3930 }
3931 }
3932 ssh2_pkt_getstring(ssh, &str, &len); /* server->client mac */
3933 for (i = 0; i < s->nmacs; i++) {
3934 if (in_commasep_string(s->maclist[i]->name, str, len)) {
3935 s->scmac_tobe = s->maclist[i];
3936 break;
3937 }
3938 }
3939 ssh2_pkt_getstring(ssh, &str, &len); /* client->server compression */
3940 for (i = 0; i < lenof(compressions) + 1; i++) {
3941 const struct ssh_compress *c =
3942 i == 0 ? s->preferred_comp : compressions[i - 1];
3943 if (in_commasep_string(c->name, str, len)) {
3944 s->cscomp_tobe = c;
3945 break;
3946 }
3947 }
3948 ssh2_pkt_getstring(ssh, &str, &len); /* server->client compression */
3949 for (i = 0; i < lenof(compressions) + 1; i++) {
3950 const struct ssh_compress *c =
3951 i == 0 ? s->preferred_comp : compressions[i - 1];
3952 if (in_commasep_string(c->name, str, len)) {
3953 s->sccomp_tobe = c;
3954 break;
3955 }
3956 }
3957 }
3958
3959 /*
3960 * Work out the number of bits of key we will need from the key
3961 * exchange. We start with the maximum key length of either
3962 * cipher...
3963 */
3964 {
3965 int csbits, scbits;
3966
3967 csbits = s->cscipher_tobe->keylen;
3968 scbits = s->sccipher_tobe->keylen;
3969 s->nbits = (csbits > scbits ? csbits : scbits);
3970 }
3971 /* The keys only have 160-bit entropy, since they're based on
3972 * a SHA-1 hash. So cap the key size at 160 bits. */
3973 if (s->nbits > 160)
3974 s->nbits = 160;
3975
3976 /*
3977 * If we're doing Diffie-Hellman group exchange, start by
3978 * requesting a group.
3979 */
3980 if (ssh->kex == &ssh_diffiehellman_gex) {
3981 logevent("Doing Diffie-Hellman group exchange");
3982 ssh->pkt_ctx |= SSH2_PKTCTX_DHGEX;
3983 /*
3984 * Work out how big a DH group we will need to allow that
3985 * much data.
3986 */
3987 s->pbits = 512 << ((s->nbits - 1) / 64);
3988 ssh2_pkt_init(ssh, SSH2_MSG_KEX_DH_GEX_REQUEST);
3989 ssh2_pkt_adduint32(ssh, s->pbits);
3990 ssh2_pkt_send(ssh);
3991
3992 crWaitUntil(ispkt);
3993 if (ssh->pktin.type != SSH2_MSG_KEX_DH_GEX_GROUP) {
3994 bombout((ssh,"expected key exchange group packet from server"));
3995 crReturn(0);
3996 }
3997 s->p = ssh2_pkt_getmp(ssh);
3998 s->g = ssh2_pkt_getmp(ssh);
3999 ssh->kex_ctx = dh_setup_group(s->p, s->g);
4000 s->kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT;
4001 s->kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY;
4002 } else {
4003 ssh->pkt_ctx |= SSH2_PKTCTX_DHGROUP1;
4004 ssh->kex_ctx = dh_setup_group1();
4005 s->kex_init_value = SSH2_MSG_KEXDH_INIT;
4006 s->kex_reply_value = SSH2_MSG_KEXDH_REPLY;
4007 }
4008
4009 logevent("Doing Diffie-Hellman key exchange");
4010 /*
4011 * Now generate and send e for Diffie-Hellman.
4012 */
4013 s->e = dh_create_e(ssh->kex_ctx, s->nbits * 2);
4014 ssh2_pkt_init(ssh, s->kex_init_value);
4015 ssh2_pkt_addmp(ssh, s->e);
4016 ssh2_pkt_send(ssh);
4017
4018 crWaitUntil(ispkt);
4019 if (ssh->pktin.type != s->kex_reply_value) {
4020 bombout((ssh,"expected key exchange reply packet from server"));
4021 crReturn(0);
4022 }
4023 ssh2_pkt_getstring(ssh, &s->hostkeydata, &s->hostkeylen);
4024 s->f = ssh2_pkt_getmp(ssh);
4025 ssh2_pkt_getstring(ssh, &s->sigdata, &s->siglen);
4026
4027 s->K = dh_find_K(ssh->kex_ctx, s->f);
4028
4029 sha_string(&ssh->exhash, s->hostkeydata, s->hostkeylen);
4030 if (ssh->kex == &ssh_diffiehellman_gex) {
4031 sha_uint32(&ssh->exhash, s->pbits);
4032 sha_mpint(&ssh->exhash, s->p);
4033 sha_mpint(&ssh->exhash, s->g);
4034 }
4035 sha_mpint(&ssh->exhash, s->e);
4036 sha_mpint(&ssh->exhash, s->f);
4037 sha_mpint(&ssh->exhash, s->K);
4038 SHA_Final(&ssh->exhash, s->exchange_hash);
4039
4040 dh_cleanup(ssh->kex_ctx);
4041
4042 #if 0
4043 debug(("Exchange hash is:\n"));
4044 dmemdump(s->exchange_hash, 20);
4045 #endif
4046
4047 s->hkey = ssh->hostkey->newkey(s->hostkeydata, s->hostkeylen);
4048 if (!s->hkey ||
4049 !ssh->hostkey->verifysig(s->hkey, s->sigdata, s->siglen,
4050 (char *)s->exchange_hash, 20)) {
4051 bombout((ssh,"Server's host key did not match the signature supplied"));
4052 crReturn(0);
4053 }
4054
4055 /*
4056 * Authenticate remote host: verify host key. (We've already
4057 * checked the signature of the exchange hash.)
4058 */
4059 s->keystr = ssh->hostkey->fmtkey(s->hkey);
4060 s->fingerprint = ssh->hostkey->fingerprint(s->hkey);
4061 verify_ssh_host_key(ssh->frontend,
4062 ssh->savedhost, ssh->savedport, ssh->hostkey->keytype,
4063 s->keystr, s->fingerprint);
4064 if (s->first_kex) { /* don't bother logging this in rekeys */
4065 logevent("Host key fingerprint is:");
4066 logevent(s->fingerprint);
4067 }
4068 sfree(s->fingerprint);
4069 sfree(s->keystr);
4070 ssh->hostkey->freekey(s->hkey);
4071
4072 /*
4073 * Send SSH2_MSG_NEWKEYS.
4074 */
4075 ssh2_pkt_init(ssh, SSH2_MSG_NEWKEYS);
4076 ssh2_pkt_send(ssh);
4077
4078 /*
4079 * Expect SSH2_MSG_NEWKEYS from server.
4080 */
4081 crWaitUntil(ispkt);
4082 if (ssh->pktin.type != SSH2_MSG_NEWKEYS) {
4083 bombout((ssh,"expected new-keys packet from server"));
4084 crReturn(0);
4085 }
4086
4087 /*
4088 * Create and initialise session keys.
4089 */
4090 if (ssh->cs_cipher_ctx)
4091 ssh->cscipher->free_context(ssh->cs_cipher_ctx);
4092 ssh->cscipher = s->cscipher_tobe;
4093 ssh->cs_cipher_ctx = ssh->cscipher->make_context();
4094
4095 if (ssh->sc_cipher_ctx)
4096 ssh->sccipher->free_context(ssh->sc_cipher_ctx);
4097 ssh->sccipher = s->sccipher_tobe;
4098 ssh->sc_cipher_ctx = ssh->sccipher->make_context();
4099
4100 if (ssh->cs_mac_ctx)
4101 ssh->csmac->free_context(ssh->cs_mac_ctx);
4102 ssh->csmac = s->csmac_tobe;
4103 ssh->cs_mac_ctx = ssh->csmac->make_context();
4104
4105 if (ssh->sc_mac_ctx)
4106 ssh->scmac->free_context(ssh->sc_mac_ctx);
4107 ssh->scmac = s->scmac_tobe;
4108 ssh->sc_mac_ctx = ssh->scmac->make_context();
4109
4110 if (ssh->cs_comp_ctx)
4111 ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
4112 ssh->cscomp = s->cscomp_tobe;
4113 ssh->cs_comp_ctx = ssh->cscomp->compress_init();
4114
4115 if (ssh->sc_comp_ctx)
4116 ssh->sccomp->decompress_cleanup(ssh->sc_comp_ctx);
4117 ssh->sccomp = s->sccomp_tobe;
4118 ssh->sc_comp_ctx = ssh->sccomp->decompress_init();
4119
4120 /*
4121 * Set IVs after keys. Here we use the exchange hash from the
4122 * _first_ key exchange.
4123 */
4124 {
4125 unsigned char keyspace[40];
4126 if (s->first_kex)
4127 memcpy(ssh->v2_session_id, s->exchange_hash,
4128 sizeof(s->exchange_hash));
4129 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'C',keyspace);
4130 ssh->cscipher->setkey(ssh->cs_cipher_ctx, keyspace);
4131 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'D',keyspace);
4132 ssh->sccipher->setkey(ssh->sc_cipher_ctx, keyspace);
4133 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'A',keyspace);
4134 ssh->cscipher->setiv(ssh->cs_cipher_ctx, keyspace);
4135 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'B',keyspace);
4136 ssh->sccipher->setiv(ssh->sc_cipher_ctx, keyspace);
4137 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'E',keyspace);
4138 ssh->csmac->setkey(ssh->cs_mac_ctx, keyspace);
4139 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'F',keyspace);
4140 ssh->scmac->setkey(ssh->sc_mac_ctx, keyspace);
4141 }
4142 logeventf(ssh, "Initialised %.200s client->server encryption",
4143 ssh->cscipher->text_name);
4144 logeventf(ssh, "Initialised %.200s server->client encryption",
4145 ssh->sccipher->text_name);
4146 if (ssh->cscomp->text_name)
4147 logeventf(ssh, "Initialised %s compression",
4148 ssh->cscomp->text_name);
4149 if (ssh->sccomp->text_name)
4150 logeventf(ssh, "Initialised %s decompression",
4151 ssh->sccomp->text_name);
4152
4153 /*
4154 * If this is the first key exchange phase, we must pass the
4155 * SSH2_MSG_NEWKEYS packet to the next layer, not because it
4156 * wants to see it but because it will need time to initialise
4157 * itself before it sees an actual packet. In subsequent key
4158 * exchange phases, we don't pass SSH2_MSG_NEWKEYS on, because
4159 * it would only confuse the layer above.
4160 */
4161 if (!s->first_kex) {
4162 crReturn(0);
4163 }
4164 s->first_kex = 0;
4165
4166 /*
4167 * Now we're encrypting. Begin returning 1 to the protocol main
4168 * function so that other things can run on top of the
4169 * transport. If we ever see a KEXINIT, we must go back to the
4170 * start.
4171 */
4172 while (!(ispkt && ssh->pktin.type == SSH2_MSG_KEXINIT)) {
4173 crReturn(1);
4174 }
4175 logevent("Server initiated key re-exchange");
4176 goto begin_key_exchange;
4177
4178 crFinish(1);
4179 }
4180
4181 /*
4182 * Add data to an SSH2 channel output buffer.
4183 */
4184 static void ssh2_add_channel_data(struct ssh_channel *c, char *buf,
4185 int len)
4186 {
4187 bufchain_add(&c->v.v2.outbuffer, buf, len);
4188 }
4189
4190 /*
4191 * Attempt to send data on an SSH2 channel.
4192 */
4193 static int ssh2_try_send(struct ssh_channel *c)
4194 {
4195 Ssh ssh = c->ssh;
4196
4197 while (c->v.v2.remwindow > 0 && bufchain_size(&c->v.v2.outbuffer) > 0) {
4198 int len;
4199 void *data;
4200 bufchain_prefix(&c->v.v2.outbuffer, &data, &len);
4201 if ((unsigned)len > c->v.v2.remwindow)
4202 len = c->v.v2.remwindow;
4203 if ((unsigned)len > c->v.v2.remmaxpkt)
4204 len = c->v.v2.remmaxpkt;
4205 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_DATA);
4206 ssh2_pkt_adduint32(ssh, c->remoteid);
4207 ssh2_pkt_addstring_start(ssh);
4208 ssh2_pkt_addstring_data(ssh, data, len);
4209 ssh2_pkt_send(ssh);
4210 bufchain_consume(&c->v.v2.outbuffer, len);
4211 c->v.v2.remwindow -= len;
4212 }
4213
4214 /*
4215 * After having sent as much data as we can, return the amount
4216 * still buffered.
4217 */
4218 return bufchain_size(&c->v.v2.outbuffer);
4219 }
4220
4221 /*
4222 * Potentially enlarge the window on an SSH2 channel.
4223 */
4224 static void ssh2_set_window(struct ssh_channel *c, unsigned newwin)
4225 {
4226 Ssh ssh = c->ssh;
4227
4228 /*
4229 * Never send WINDOW_ADJUST for a channel that the remote side
4230 * already thinks it's closed; there's no point, since it won't
4231 * be sending any more data anyway.
4232 */
4233 if (c->closes != 0)
4234 return;
4235
4236 if (newwin > c->v.v2.locwindow) {
4237 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST);
4238 ssh2_pkt_adduint32(ssh, c->remoteid);
4239 ssh2_pkt_adduint32(ssh, newwin - c->v.v2.locwindow);
4240 ssh2_pkt_send(ssh);
4241 c->v.v2.locwindow = newwin;
4242 }
4243 }
4244
4245 /*
4246 * Handle the SSH2 userauth and connection layers.
4247 */
4248 static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
4249 {
4250 struct do_ssh2_authconn_state {
4251 enum {
4252 AUTH_INVALID, AUTH_PUBLICKEY_AGENT, AUTH_PUBLICKEY_FILE,
4253 AUTH_PASSWORD,
4254 AUTH_KEYBOARD_INTERACTIVE
4255 } method;
4256 enum {
4257 AUTH_TYPE_NONE,
4258 AUTH_TYPE_PUBLICKEY,
4259 AUTH_TYPE_PUBLICKEY_OFFER_LOUD,
4260 AUTH_TYPE_PUBLICKEY_OFFER_QUIET,
4261 AUTH_TYPE_PASSWORD,
4262 AUTH_TYPE_KEYBOARD_INTERACTIVE,
4263 AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET
4264 } type;
4265 int gotit, need_pw, can_pubkey, can_passwd, can_keyb_inter;
4266 int tried_pubkey_config, tried_agent, tried_keyb_inter;
4267 int kbd_inter_running;
4268 int we_are_in;
4269 int num_prompts, curr_prompt, echo;
4270 char username[100];
4271 int got_username;
4272 char pwprompt[200];
4273 char password[100];
4274 void *publickey_blob;
4275 int publickey_bloblen;
4276 unsigned char request[5], *response, *p;
4277 int responselen;
4278 int keyi, nkeys;
4279 int authed;
4280 char *pkblob, *alg, *commentp;
4281 int pklen, alglen, commentlen;
4282 int siglen, retlen, len;
4283 char *q, *agentreq, *ret;
4284 int try_send;
4285 };
4286 crState(do_ssh2_authconn_state);
4287
4288 crBegin(ssh->do_ssh2_authconn_crstate);
4289
4290 /*
4291 * Request userauth protocol, and await a response to it.
4292 */
4293 ssh2_pkt_init(ssh, SSH2_MSG_SERVICE_REQUEST);
4294 ssh2_pkt_addstring(ssh, "ssh-userauth");
4295 ssh2_pkt_send(ssh);
4296 crWaitUntilV(ispkt);
4297 if (ssh->pktin.type != SSH2_MSG_SERVICE_ACCEPT) {
4298 bombout((ssh,"Server refused user authentication protocol"));
4299 crReturnV;
4300 }
4301
4302 /*
4303 * We repeat this whole loop, including the username prompt,
4304 * until we manage a successful authentication. If the user
4305 * types the wrong _password_, they can be sent back to the
4306 * beginning to try another username, if this is configured on.
4307 * (If they specify a username in the config, they are never
4308 * asked, even if they do give a wrong password.)
4309 *
4310 * I think this best serves the needs of
4311 *
4312 * - the people who have no configuration, no keys, and just
4313 * want to try repeated (username,password) pairs until they
4314 * type both correctly
4315 *
4316 * - people who have keys and configuration but occasionally
4317 * need to fall back to passwords
4318 *
4319 * - people with a key held in Pageant, who might not have
4320 * logged in to a particular machine before; so they want to
4321 * type a username, and then _either_ their key will be
4322 * accepted, _or_ they will type a password. If they mistype
4323 * the username they will want to be able to get back and
4324 * retype it!
4325 */
4326 s->username[0] = '\0';
4327 s->got_username = FALSE;
4328 do {
4329 /*
4330 * Get a username.
4331 */
4332 if (s->got_username && !cfg.change_username) {
4333 /*
4334 * We got a username last time round this loop, and
4335 * with change_username turned off we don't try to get
4336 * it again.
4337 */
4338 } else if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
4339 if (ssh_get_line && !ssh_getline_pw_only) {
4340 if (!ssh_get_line("login as: ",
4341 s->username, sizeof(s->username), FALSE)) {
4342 /*
4343 * get_line failed to get a username.
4344 * Terminate.
4345 */
4346 logevent("No username provided. Abandoning session.");
4347 ssh->state = SSH_STATE_CLOSED;
4348 crReturnV;
4349 }
4350 } else {
4351 int ret; /* need not be saved across crReturn */
4352 c_write_str(ssh, "login as: ");
4353 ssh->send_ok = 1;
4354 setup_userpass_input(ssh, s->username, sizeof(s->username), 1);
4355 do {
4356 crWaitUntilV(!ispkt);
4357 ret = process_userpass_input(ssh, in, inlen);
4358 } while (ret == 0);
4359 if (ret < 0)
4360 cleanup_exit(0);
4361 c_write_str(ssh, "\r\n");
4362 }
4363 s->username[strcspn(s->username, "\n\r")] = '\0';
4364 } else {
4365 char *stuff;
4366 strncpy(s->username, cfg.username, sizeof(s->username));
4367 s->username[sizeof(s->username)-1] = '\0';
4368 if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
4369 stuff = dupprintf("Using username \"%s\".\r\n", s->username);
4370 c_write_str(ssh, stuff);
4371 sfree(stuff);
4372 }
4373 }
4374 s->got_username = TRUE;
4375
4376 /*
4377 * Send an authentication request using method "none": (a)
4378 * just in case it succeeds, and (b) so that we know what
4379 * authentication methods we can usefully try next.
4380 */
4381 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4382
4383 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4384 ssh2_pkt_addstring(ssh, s->username);
4385 ssh2_pkt_addstring(ssh, "ssh-connection");/* service requested */
4386 ssh2_pkt_addstring(ssh, "none"); /* method */
4387 ssh2_pkt_send(ssh);
4388 s->type = AUTH_TYPE_NONE;
4389 s->gotit = FALSE;
4390 s->we_are_in = FALSE;
4391
4392 s->tried_pubkey_config = FALSE;
4393 s->tried_agent = FALSE;
4394 s->tried_keyb_inter = FALSE;
4395 s->kbd_inter_running = FALSE;
4396 /* Load the pub half of cfg.keyfile so we notice if it's in Pageant */
4397 if (*cfg.keyfile) {
4398 int keytype;
4399 logeventf(ssh, "Reading private key file \"%.150s\"", cfg.keyfile);
4400 keytype = key_type(cfg.keyfile);
4401 if (keytype == SSH_KEYTYPE_SSH2) {
4402 s->publickey_blob =
4403 ssh2_userkey_loadpub(cfg.keyfile, NULL,
4404 &s->publickey_bloblen);
4405 } else {
4406 char *msgbuf;
4407 logeventf(ssh, "Unable to use this key file (%s)",
4408 key_type_to_str(keytype));
4409 msgbuf = dupprintf("Unable to use key file \"%.150s\""
4410 " (%s)\r\n", cfg.keyfile,
4411 key_type_to_str(keytype));
4412 c_write_str(ssh, msgbuf);
4413 sfree(msgbuf);
4414 s->publickey_blob = NULL;
4415 }
4416 } else
4417 s->publickey_blob = NULL;
4418
4419 while (1) {
4420 /*
4421 * Wait for the result of the last authentication request.
4422 */
4423 if (!s->gotit)
4424 crWaitUntilV(ispkt);
4425 while (ssh->pktin.type == SSH2_MSG_USERAUTH_BANNER) {
4426 char *banner;
4427 int size;
4428 /*
4429 * Don't show the banner if we're operating in
4430 * non-verbose non-interactive mode. (It's probably
4431 * a script, which means nobody will read the
4432 * banner _anyway_, and moreover the printing of
4433 * the banner will screw up processing on the
4434 * output of (say) plink.)
4435 */
4436 if (flags & (FLAG_VERBOSE | FLAG_INTERACTIVE)) {
4437 ssh2_pkt_getstring(ssh, &banner, &size);
4438 if (banner)
4439 c_write_untrusted(ssh, banner, size);
4440 }
4441 crWaitUntilV(ispkt);
4442 }
4443 if (ssh->pktin.type == SSH2_MSG_USERAUTH_SUCCESS) {
4444 logevent("Access granted");
4445 s->we_are_in = TRUE;
4446 break;
4447 }
4448
4449 if (s->kbd_inter_running &&
4450 ssh->pktin.type == SSH2_MSG_USERAUTH_INFO_REQUEST) {
4451 /*
4452 * This is either a further set-of-prompts packet
4453 * in keyboard-interactive authentication, or it's
4454 * the same one and we came back here with `gotit'
4455 * set. In the former case, we must reset the
4456 * curr_prompt variable.
4457 */
4458 if (!s->gotit)
4459 s->curr_prompt = 0;
4460 } else if (ssh->pktin.type != SSH2_MSG_USERAUTH_FAILURE) {
4461 bombout((ssh,"Strange packet received during authentication: type %d",
4462 ssh->pktin.type));
4463 crReturnV;
4464 }
4465
4466 s->gotit = FALSE;
4467
4468 /*
4469 * OK, we're now sitting on a USERAUTH_FAILURE message, so
4470 * we can look at the string in it and know what we can
4471 * helpfully try next.
4472 */
4473 if (ssh->pktin.type == SSH2_MSG_USERAUTH_FAILURE) {
4474 char *methods;
4475 int methlen;
4476 ssh2_pkt_getstring(ssh, &methods, &methlen);
4477 s->kbd_inter_running = FALSE;
4478 if (!ssh2_pkt_getbool(ssh)) {
4479 /*
4480 * We have received an unequivocal Access
4481 * Denied. This can translate to a variety of
4482 * messages:
4483 *
4484 * - if we'd just tried "none" authentication,
4485 * it's not worth printing anything at all
4486 *
4487 * - if we'd just tried a public key _offer_,
4488 * the message should be "Server refused our
4489 * key" (or no message at all if the key
4490 * came from Pageant)
4491 *
4492 * - if we'd just tried anything else, the
4493 * message really should be "Access denied".
4494 *
4495 * Additionally, if we'd just tried password
4496 * authentication, we should break out of this
4497 * whole loop so as to go back to the username
4498 * prompt.
4499 */
4500 if (s->type == AUTH_TYPE_NONE) {
4501 /* do nothing */
4502 } else if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD ||
4503 s->type == AUTH_TYPE_PUBLICKEY_OFFER_QUIET) {
4504 if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD)
4505 c_write_str(ssh, "Server refused our key\r\n");
4506 logevent("Server refused public key");
4507 } else if (s->type==AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET) {
4508 /* server declined keyboard-interactive; ignore */
4509 } else {
4510 c_write_str(ssh, "Access denied\r\n");
4511 logevent("Access denied");
4512 if (s->type == AUTH_TYPE_PASSWORD) {
4513 s->we_are_in = FALSE;
4514 break;
4515 }
4516 }
4517 } else {
4518 c_write_str(ssh, "Further authentication required\r\n");
4519 logevent("Further authentication required");
4520 }
4521
4522 s->can_pubkey =
4523 in_commasep_string("publickey", methods, methlen);
4524 s->can_passwd =
4525 in_commasep_string("password", methods, methlen);
4526 s->can_keyb_inter = cfg.try_ki_auth &&
4527 in_commasep_string("keyboard-interactive", methods, methlen);
4528 }
4529
4530 s->method = 0;
4531 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4532
4533 /*
4534 * Most password/passphrase prompts will be
4535 * non-echoing, so we set this to 0 by default.
4536 * Exception is that some keyboard-interactive prompts
4537 * can be echoing, in which case we'll set this to 1.
4538 */
4539 s->echo = 0;
4540
4541 if (!s->method && s->can_pubkey &&
4542 agent_exists() && !s->tried_agent) {
4543 /*
4544 * Attempt public-key authentication using Pageant.
4545 */
4546 void *r;
4547 s->authed = FALSE;
4548
4549 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4550 ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
4551
4552 s->tried_agent = TRUE;
4553
4554 logevent("Pageant is running. Requesting keys.");
4555
4556 /* Request the keys held by the agent. */
4557 PUT_32BIT(s->request, 1);
4558 s->request[4] = SSH2_AGENTC_REQUEST_IDENTITIES;
4559 agent_query(s->request, 5, &r, &s->responselen);
4560 s->response = (unsigned char *) r;
4561 if (s->response && s->responselen >= 5 &&
4562 s->response[4] == SSH2_AGENT_IDENTITIES_ANSWER) {
4563 s->p = s->response + 5;
4564 s->nkeys = GET_32BIT(s->p);
4565 s->p += 4;
4566 {
4567 char buf[64];
4568 sprintf(buf, "Pageant has %d SSH2 keys", s->nkeys);
4569 logevent(buf);
4570 }
4571 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
4572 void *vret;
4573
4574 {
4575 char buf[64];
4576 sprintf(buf, "Trying Pageant key #%d", s->keyi);
4577 logevent(buf);
4578 }
4579 s->pklen = GET_32BIT(s->p);
4580 s->p += 4;
4581 if (s->publickey_blob &&
4582 s->pklen == s->publickey_bloblen &&
4583 !memcmp(s->p, s->publickey_blob,
4584 s->publickey_bloblen)) {
4585 logevent("This key matches configured key file");
4586 s->tried_pubkey_config = 1;
4587 }
4588 s->pkblob = (char *)s->p;
4589 s->p += s->pklen;
4590 s->alglen = GET_32BIT(s->pkblob);
4591 s->alg = s->pkblob + 4;
4592 s->commentlen = GET_32BIT(s->p);
4593 s->p += 4;
4594 s->commentp = (char *)s->p;
4595 s->p += s->commentlen;
4596 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4597 ssh2_pkt_addstring(ssh, s->username);
4598 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4599 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4600 ssh2_pkt_addbool(ssh, FALSE); /* no signature included */
4601 ssh2_pkt_addstring_start(ssh);
4602 ssh2_pkt_addstring_data(ssh, s->alg, s->alglen);
4603 ssh2_pkt_addstring_start(ssh);
4604 ssh2_pkt_addstring_data(ssh, s->pkblob, s->pklen);
4605 ssh2_pkt_send(ssh);
4606
4607 crWaitUntilV(ispkt);
4608 if (ssh->pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
4609 logevent("Key refused");
4610 continue;
4611 }
4612
4613 if (flags & FLAG_VERBOSE) {
4614 c_write_str(ssh, "Authenticating with "
4615 "public key \"");
4616 c_write(ssh, s->commentp, s->commentlen);
4617 c_write_str(ssh, "\" from agent\r\n");
4618 }
4619
4620 /*
4621 * Server is willing to accept the key.
4622 * Construct a SIGN_REQUEST.
4623 */
4624 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4625 ssh2_pkt_addstring(ssh, s->username);
4626 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4627 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4628 ssh2_pkt_addbool(ssh, TRUE);
4629 ssh2_pkt_addstring_start(ssh);
4630 ssh2_pkt_addstring_data(ssh, s->alg, s->alglen);
4631 ssh2_pkt_addstring_start(ssh);
4632 ssh2_pkt_addstring_data(ssh, s->pkblob, s->pklen);
4633
4634 s->siglen = ssh->pktout.length - 5 + 4 + 20;
4635 s->len = 1; /* message type */
4636 s->len += 4 + s->pklen; /* key blob */
4637 s->len += 4 + s->siglen; /* data to sign */
4638 s->len += 4; /* flags */
4639 s->agentreq = smalloc(4 + s->len);
4640 PUT_32BIT(s->agentreq, s->len);
4641 s->q = s->agentreq + 4;
4642 *s->q++ = SSH2_AGENTC_SIGN_REQUEST;
4643 PUT_32BIT(s->q, s->pklen);
4644 s->q += 4;
4645 memcpy(s->q, s->pkblob, s->pklen);
4646 s->q += s->pklen;
4647 PUT_32BIT(s->q, s->siglen);
4648 s->q += 4;
4649 /* Now the data to be signed... */
4650 PUT_32BIT(s->q, 20);
4651 s->q += 4;
4652 memcpy(s->q, ssh->v2_session_id, 20);
4653 s->q += 20;
4654 memcpy(s->q, ssh->pktout.data + 5,
4655 ssh->pktout.length - 5);
4656 s->q += ssh->pktout.length - 5;
4657 /* And finally the (zero) flags word. */
4658 PUT_32BIT(s->q, 0);
4659 agent_query(s->agentreq, s->len + 4, &vret, &s->retlen);
4660 s->ret = vret;
4661 sfree(s->agentreq);
4662 if (s->ret) {
4663 if (s->ret[4] == SSH2_AGENT_SIGN_RESPONSE) {
4664 logevent("Sending Pageant's response");
4665 ssh2_add_sigblob(ssh, s->pkblob, s->pklen,
4666 s->ret + 9,
4667 GET_32BIT(s->ret + 5));
4668 ssh2_pkt_send(ssh);
4669 s->authed = TRUE;
4670 break;
4671 } else {
4672 logevent
4673 ("Pageant failed to answer challenge");
4674 sfree(s->ret);
4675 }
4676 }
4677 }
4678 if (s->authed)
4679 continue;
4680 }
4681 }
4682
4683 if (!s->method && s->can_pubkey && s->publickey_blob
4684 && !s->tried_pubkey_config) {
4685 unsigned char *pub_blob;
4686 char *algorithm, *comment;
4687 int pub_blob_len;
4688
4689 s->tried_pubkey_config = TRUE;
4690
4691 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4692 ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
4693
4694 /*
4695 * Try the public key supplied in the configuration.
4696 *
4697 * First, offer the public blob to see if the server is
4698 * willing to accept it.
4699 */
4700 pub_blob =
4701 (unsigned char *)ssh2_userkey_loadpub(cfg.keyfile,
4702 &algorithm,
4703 &pub_blob_len);
4704 if (pub_blob) {
4705 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4706 ssh2_pkt_addstring(ssh, s->username);
4707 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4708 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4709 ssh2_pkt_addbool(ssh, FALSE); /* no signature included */
4710 ssh2_pkt_addstring(ssh, algorithm);
4711 ssh2_pkt_addstring_start(ssh);
4712 ssh2_pkt_addstring_data(ssh, (char *)pub_blob,
4713 pub_blob_len);
4714 ssh2_pkt_send(ssh);
4715 logevent("Offered public key"); /* FIXME */
4716
4717 crWaitUntilV(ispkt);
4718 if (ssh->pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
4719 s->gotit = TRUE;
4720 s->type = AUTH_TYPE_PUBLICKEY_OFFER_LOUD;
4721 continue; /* key refused; give up on it */
4722 }
4723
4724 logevent("Offer of public key accepted");
4725 /*
4726 * Actually attempt a serious authentication using
4727 * the key.
4728 */
4729 if (ssh2_userkey_encrypted(cfg.keyfile, &comment)) {
4730 sprintf(s->pwprompt,
4731 "Passphrase for key \"%.100s\": ",
4732 comment);
4733 s->need_pw = TRUE;
4734 } else {
4735 s->need_pw = FALSE;
4736 }
4737 c_write_str(ssh, "Authenticating with public key \"");
4738 c_write_str(ssh, comment);
4739 c_write_str(ssh, "\"\r\n");
4740 s->method = AUTH_PUBLICKEY_FILE;
4741 }
4742 }
4743
4744 if (!s->method && s->can_keyb_inter && !s->tried_keyb_inter) {
4745 s->method = AUTH_KEYBOARD_INTERACTIVE;
4746 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
4747 s->tried_keyb_inter = TRUE;
4748
4749 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4750 ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;
4751
4752 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4753 ssh2_pkt_addstring(ssh, s->username);
4754 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4755 ssh2_pkt_addstring(ssh, "keyboard-interactive"); /* method */
4756 ssh2_pkt_addstring(ssh, ""); /* lang */
4757 ssh2_pkt_addstring(ssh, "");
4758 ssh2_pkt_send(ssh);
4759
4760 crWaitUntilV(ispkt);
4761 if (ssh->pktin.type != SSH2_MSG_USERAUTH_INFO_REQUEST) {
4762 if (ssh->pktin.type == SSH2_MSG_USERAUTH_FAILURE)
4763 s->gotit = TRUE;
4764 logevent("Keyboard-interactive authentication refused");
4765 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET;
4766 continue;
4767 }
4768
4769 s->kbd_inter_running = TRUE;
4770 s->curr_prompt = 0;
4771 }
4772
4773 if (s->kbd_inter_running) {
4774 s->method = AUTH_KEYBOARD_INTERACTIVE;
4775 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
4776 s->tried_keyb_inter = TRUE;
4777
4778 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4779 ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;
4780
4781 if (s->curr_prompt == 0) {
4782 /*
4783 * We've got a fresh USERAUTH_INFO_REQUEST.
4784 * Display header data, and start going through
4785 * the prompts.
4786 */
4787 char *name, *inst, *lang;
4788 int name_len, inst_len, lang_len;
4789
4790 ssh2_pkt_getstring(ssh, &name, &name_len);
4791 ssh2_pkt_getstring(ssh, &inst, &inst_len);
4792 ssh2_pkt_getstring(ssh, &lang, &lang_len);
4793 if (name_len > 0) {
4794 c_write_untrusted(ssh, name, name_len);
4795 c_write_str(ssh, "\r\n");
4796 }
4797 if (inst_len > 0) {
4798 c_write_untrusted(ssh, inst, inst_len);
4799 c_write_str(ssh, "\r\n");
4800 }
4801 s->num_prompts = ssh2_pkt_getuint32(ssh);
4802 }
4803
4804 /*
4805 * If there are prompts remaining in the packet,
4806 * display one and get a response.
4807 */
4808 if (s->curr_prompt < s->num_prompts) {
4809 char *prompt;
4810 int prompt_len;
4811
4812 ssh2_pkt_getstring(ssh, &prompt, &prompt_len);
4813 if (prompt_len > 0) {
4814 strncpy(s->pwprompt, prompt, sizeof(s->pwprompt));
4815 s->pwprompt[prompt_len < sizeof(s->pwprompt) ?
4816 prompt_len : sizeof(s->pwprompt)-1] = '\0';
4817 } else {
4818 strcpy(s->pwprompt,
4819 "<server failed to send prompt>: ");
4820 }
4821 s->echo = ssh2_pkt_getbool(ssh);
4822 s->need_pw = TRUE;
4823 } else
4824 s->need_pw = FALSE;
4825 }
4826
4827 if (!s->method && s->can_passwd) {
4828 s->method = AUTH_PASSWORD;
4829 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4830 ssh->pkt_ctx |= SSH2_PKTCTX_PASSWORD;
4831 sprintf(s->pwprompt, "%.90s@%.90s's password: ", s->username,
4832 ssh->savedhost);
4833 s->need_pw = TRUE;
4834 }
4835
4836 if (s->need_pw) {
4837 if (ssh_get_line) {
4838 if (!ssh_get_line(s->pwprompt, s->password,
4839 sizeof(s->password), TRUE)) {
4840 /*
4841 * get_line failed to get a password (for
4842 * example because one was supplied on the
4843 * command line which has already failed to
4844 * work). Terminate.
4845 */
4846 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
4847 ssh2_pkt_adduint32(ssh,SSH2_DISCONNECT_BY_APPLICATION);
4848 ssh2_pkt_addstring(ssh, "No more passwords available"
4849 " to try");
4850 ssh2_pkt_addstring(ssh, "en"); /* language tag */
4851 ssh2_pkt_send(ssh);
4852 logevent("Unable to authenticate");
4853 connection_fatal(ssh->frontend,
4854 "Unable to authenticate");
4855 ssh->state = SSH_STATE_CLOSED;
4856 crReturnV;
4857 }
4858 } else {
4859 int ret; /* need not be saved across crReturn */
4860 c_write_untrusted(ssh, s->pwprompt, strlen(s->pwprompt));
4861 ssh->send_ok = 1;
4862
4863 setup_userpass_input(ssh, s->password,
4864 sizeof(s->password), s->echo);
4865 do {
4866 crWaitUntilV(!ispkt);
4867 ret = process_userpass_input(ssh, in, inlen);
4868 } while (ret == 0);
4869 if (ret < 0)
4870 cleanup_exit(0);
4871 c_write_str(ssh, "\r\n");
4872 }
4873 }
4874
4875 if (s->method == AUTH_PUBLICKEY_FILE) {
4876 /*
4877 * We have our passphrase. Now try the actual authentication.
4878 */
4879 struct ssh2_userkey *key;
4880
4881 key = ssh2_load_userkey(cfg.keyfile, s->password);
4882 if (key == SSH2_WRONG_PASSPHRASE || key == NULL) {
4883 if (key == SSH2_WRONG_PASSPHRASE) {
4884 c_write_str(ssh, "Wrong passphrase\r\n");
4885 s->tried_pubkey_config = FALSE;
4886 } else {
4887 c_write_str(ssh, "Unable to load private key\r\n");
4888 s->tried_pubkey_config = TRUE;
4889 }
4890 /* Send a spurious AUTH_NONE to return to the top. */
4891 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4892 ssh2_pkt_addstring(ssh, s->username);
4893 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4894 ssh2_pkt_addstring(ssh, "none"); /* method */
4895 ssh2_pkt_send(ssh);
4896 s->type = AUTH_TYPE_NONE;
4897 } else {
4898 unsigned char *pkblob, *sigblob, *sigdata;
4899 int pkblob_len, sigblob_len, sigdata_len;
4900
4901 /*
4902 * We have loaded the private key and the server
4903 * has announced that it's willing to accept it.
4904 * Hallelujah. Generate a signature and send it.
4905 */
4906 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4907 ssh2_pkt_addstring(ssh, s->username);
4908 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4909 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4910 ssh2_pkt_addbool(ssh, TRUE);
4911 ssh2_pkt_addstring(ssh, key->alg->name);
4912 pkblob = key->alg->public_blob(key->data, &pkblob_len);
4913 ssh2_pkt_addstring_start(ssh);
4914 ssh2_pkt_addstring_data(ssh, (char *)pkblob, pkblob_len);
4915
4916 /*
4917 * The data to be signed is:
4918 *
4919 * string session-id
4920 *
4921 * followed by everything so far placed in the
4922 * outgoing packet.
4923 */
4924 sigdata_len = ssh->pktout.length - 5 + 4 + 20;
4925 sigdata = smalloc(sigdata_len);
4926 PUT_32BIT(sigdata, 20);
4927 memcpy(sigdata + 4, ssh->v2_session_id, 20);
4928 memcpy(sigdata + 24, ssh->pktout.data + 5,
4929 ssh->pktout.length - 5);
4930 sigblob = key->alg->sign(key->data, (char *)sigdata,
4931 sigdata_len, &sigblob_len);
4932 ssh2_add_sigblob(ssh, pkblob, pkblob_len,
4933 sigblob, sigblob_len);
4934 sfree(pkblob);
4935 sfree(sigblob);
4936 sfree(sigdata);
4937
4938 ssh2_pkt_send(ssh);
4939 s->type = AUTH_TYPE_PUBLICKEY;
4940 }
4941 } else if (s->method == AUTH_PASSWORD) {
4942 /*
4943 * We send the password packet lumped tightly together with
4944 * an SSH_MSG_IGNORE packet. The IGNORE packet contains a
4945 * string long enough to make the total length of the two
4946 * packets constant. This should ensure that a passive
4947 * listener doing traffic analyis can't work out the length
4948 * of the password.
4949 *
4950 * For this to work, we need an assumption about the
4951 * maximum length of the password packet. I think 256 is
4952 * pretty conservative. Anyone using a password longer than
4953 * that probably doesn't have much to worry about from
4954 * people who find out how long their password is!
4955 */
4956 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4957 ssh2_pkt_addstring(ssh, s->username);
4958 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4959 ssh2_pkt_addstring(ssh, "password");
4960 ssh2_pkt_addbool(ssh, FALSE);
4961 ssh2_pkt_addstring(ssh, s->password);
4962 ssh2_pkt_defer(ssh);
4963 /*
4964 * We'll include a string that's an exact multiple of the
4965 * cipher block size. If the cipher is NULL for some
4966 * reason, we don't do this trick at all because we gain
4967 * nothing by it.
4968 */
4969 if (ssh->cscipher) {
4970 int stringlen, i;
4971
4972 stringlen = (256 - ssh->deferred_len);
4973 stringlen += ssh->cscipher->blksize - 1;
4974 stringlen -= (stringlen % ssh->cscipher->blksize);
4975 if (ssh->cscomp) {
4976 /*
4977 * Temporarily disable actual compression,
4978 * so we can guarantee to get this string
4979 * exactly the length we want it. The
4980 * compression-disabling routine should
4981 * return an integer indicating how many
4982 * bytes we should adjust our string length
4983 * by.
4984 */
4985 stringlen -=
4986 ssh->cscomp->disable_compression(ssh->cs_comp_ctx);
4987 }
4988 ssh2_pkt_init(ssh, SSH2_MSG_IGNORE);
4989 ssh2_pkt_addstring_start(ssh);
4990 for (i = 0; i < stringlen; i++) {
4991 char c = (char) random_byte();
4992 ssh2_pkt_addstring_data(ssh, &c, 1);
4993 }
4994 ssh2_pkt_defer(ssh);
4995 }
4996 ssh_pkt_defersend(ssh);
4997 logevent("Sent password");
4998 s->type = AUTH_TYPE_PASSWORD;
4999 } else if (s->method == AUTH_KEYBOARD_INTERACTIVE) {
5000 if (s->curr_prompt == 0) {
5001 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_INFO_RESPONSE);
5002 ssh2_pkt_adduint32(ssh, s->num_prompts);
5003 }
5004 if (s->need_pw) { /* only add pw if we just got one! */
5005 ssh2_pkt_addstring(ssh, s->password);
5006 memset(s->password, 0, sizeof(s->password));
5007 s->curr_prompt++;
5008 }
5009 if (s->curr_prompt >= s->num_prompts) {
5010 ssh2_pkt_send(ssh);
5011 } else {
5012 /*
5013 * If there are prompts remaining, we set
5014 * `gotit' so that we won't attempt to get
5015 * another packet. Then we go back round the
5016 * loop and will end up retrieving another
5017 * prompt out of the existing packet. Funky or
5018 * what?
5019 */
5020 s->gotit = TRUE;
5021 }
5022 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
5023 } else {
5024 c_write_str(ssh, "No supported authentication methods"
5025 " left to try!\r\n");
5026 logevent("No supported authentications offered."
5027 " Disconnecting");
5028 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5029 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5030 ssh2_pkt_addstring(ssh, "No supported authentication"
5031 " methods available");
5032 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5033 ssh2_pkt_send(ssh);
5034 ssh->state = SSH_STATE_CLOSED;
5035 crReturnV;
5036 }
5037 }
5038 } while (!s->we_are_in);
5039
5040 /*
5041 * Now we're authenticated for the connection protocol. The
5042 * connection protocol will automatically have started at this
5043 * point; there's no need to send SERVICE_REQUEST.
5044 */
5045
5046 /*
5047 * So now create a channel with a session in it.
5048 */
5049 ssh->channels = newtree234(ssh_channelcmp);
5050 ssh->mainchan = smalloc(sizeof(struct ssh_channel));
5051 ssh->mainchan->ssh = ssh;
5052 ssh->mainchan->localid = alloc_channel_id(ssh);
5053 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN);
5054 ssh2_pkt_addstring(ssh, "session");
5055 ssh2_pkt_adduint32(ssh, ssh->mainchan->localid);
5056 ssh->mainchan->v.v2.locwindow = OUR_V2_WINSIZE;
5057 ssh2_pkt_adduint32(ssh, ssh->mainchan->v.v2.locwindow);/* our window size */
5058 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
5059 ssh2_pkt_send(ssh);
5060 crWaitUntilV(ispkt);
5061 if (ssh->pktin.type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
5062 bombout((ssh,"Server refused to open a session"));
5063 crReturnV;
5064 /* FIXME: error data comes back in FAILURE packet */
5065 }
5066 if (ssh2_pkt_getuint32(ssh) != ssh->mainchan->localid) {
5067 bombout((ssh,"Server's channel confirmation cited wrong channel"));
5068 crReturnV;
5069 }
5070 ssh->mainchan->remoteid = ssh2_pkt_getuint32(ssh);
5071 ssh->mainchan->type = CHAN_MAINSESSION;
5072 ssh->mainchan->closes = 0;
5073 ssh->mainchan->v.v2.remwindow = ssh2_pkt_getuint32(ssh);
5074 ssh->mainchan->v.v2.remmaxpkt = ssh2_pkt_getuint32(ssh);
5075 bufchain_init(&ssh->mainchan->v.v2.outbuffer);
5076 add234(ssh->channels, ssh->mainchan);
5077 logevent("Opened channel for session");
5078
5079 /*
5080 * Potentially enable X11 forwarding.
5081 */
5082 if (cfg.x11_forward) {
5083 char proto[20], data[64];
5084 logevent("Requesting X11 forwarding");
5085 ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
5086 data, sizeof(data));
5087 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5088 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
5089 ssh2_pkt_addstring(ssh, "x11-req");
5090 ssh2_pkt_addbool(ssh, 1); /* want reply */
5091 ssh2_pkt_addbool(ssh, 0); /* many connections */
5092 ssh2_pkt_addstring(ssh, proto);
5093 ssh2_pkt_addstring(ssh, data);
5094 ssh2_pkt_adduint32(ssh, x11_get_screen_number(cfg.x11_display));
5095 ssh2_pkt_send(ssh);
5096
5097 do {
5098 crWaitUntilV(ispkt);
5099 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5100 unsigned i = ssh2_pkt_getuint32(ssh);
5101 struct ssh_channel *c;
5102 c = find234(ssh->channels, &i, ssh_channelfind);
5103 if (!c)
5104 continue; /* nonexistent channel */
5105 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5106 }
5107 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5108
5109 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5110 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5111 bombout((ssh,"Unexpected response to X11 forwarding request:"
5112 " packet type %d", ssh->pktin.type));
5113 crReturnV;
5114 }
5115 logevent("X11 forwarding refused");
5116 } else {
5117 logevent("X11 forwarding enabled");
5118 ssh->X11_fwd_enabled = TRUE;
5119 }
5120 }
5121
5122 /*
5123 * Enable port forwardings.
5124 */
5125 {
5126 char type;
5127 int n;
5128 int sport,dport,sserv,dserv;
5129 char sports[256], dports[256], saddr[256], host[256];
5130
5131 ssh->rportfwds = newtree234(ssh_rportcmp_ssh2);
5132 /* Add port forwardings. */
5133 ssh->portfwd_strptr = cfg.portfwd;
5134 while (*ssh->portfwd_strptr) {
5135 type = *ssh->portfwd_strptr++;
5136 saddr[0] = '\0';
5137 n = 0;
5138 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != '\t') {
5139 if (*ssh->portfwd_strptr == ':') {
5140 /*
5141 * We've seen a colon in the middle of the
5142 * source port number. This means that
5143 * everything we've seen until now is the
5144 * source _address_, so we'll move it into
5145 * saddr and start sports from the beginning
5146 * again.
5147 */
5148 ssh->portfwd_strptr++;
5149 sports[n] = '\0';
5150 strcpy(saddr, sports);
5151 n = 0;
5152 }
5153 if (n < 255) sports[n++] = *ssh->portfwd_strptr++;
5154 }
5155 sports[n] = 0;
5156 if (*ssh->portfwd_strptr == '\t')
5157 ssh->portfwd_strptr++;
5158 n = 0;
5159 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':') {
5160 if (n < 255) host[n++] = *ssh->portfwd_strptr++;
5161 }
5162 host[n] = 0;
5163 if (*ssh->portfwd_strptr == ':')
5164 ssh->portfwd_strptr++;
5165 n = 0;
5166 while (*ssh->portfwd_strptr) {
5167 if (n < 255) dports[n++] = *ssh->portfwd_strptr++;
5168 }
5169 dports[n] = 0;
5170 ssh->portfwd_strptr++;
5171 dport = atoi(dports);
5172 dserv = 0;
5173 if (dport == 0) {
5174 dserv = 1;
5175 dport = net_service_lookup(dports);
5176 if (!dport) {
5177 logeventf(ssh, "Service lookup failed for destination"
5178 " port \"%s\"", dports);
5179 }
5180 }
5181 sport = atoi(sports);
5182 sserv = 0;
5183 if (sport == 0) {
5184 sserv = 1;
5185 sport = net_service_lookup(sports);
5186 if (!sport) {
5187 logeventf(ssh, "Service lookup failed for source"
5188 " port \"%s\"", sports);
5189 }
5190 }
5191 if (sport && dport) {
5192 if (type == 'L') {
5193 pfd_addforward(host, dport, *saddr ? saddr : NULL,
5194 sport, ssh);
5195 logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
5196 " forwarding to %s:%.*s%.*s%d%.*s",
5197 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
5198 (int)(*saddr?1:0), ":",
5199 (int)(sserv ? strlen(sports) : 0), sports,
5200 sserv, "(", sport, sserv, ")",
5201 host,
5202 (int)(dserv ? strlen(dports) : 0), dports,
5203 dserv, "(", dport, dserv, ")");
5204 } else {
5205 struct ssh_rportfwd *pf;
5206 pf = smalloc(sizeof(*pf));
5207 strcpy(pf->dhost, host);
5208 pf->dport = dport;
5209 pf->sport = sport;
5210 if (add234(ssh->rportfwds, pf) != pf) {
5211 logeventf(ssh, "Duplicate remote port forwarding"
5212 " to %s:%d", host, dport);
5213 sfree(pf);
5214 } else {
5215 logeventf(ssh, "Requesting remote port "
5216 "%.*s%.*s%.*s%.*s%d%.*s"
5217 " forward to %s:%.*s%.*s%d%.*s",
5218 (int)(*saddr?strlen(saddr):0),
5219 *saddr?saddr:NULL,
5220 (int)(*saddr?1:0), ":",
5221 (int)(sserv ? strlen(sports) : 0), sports,
5222 sserv, "(", sport, sserv, ")",
5223 host,
5224 (int)(dserv ? strlen(dports) : 0), dports,
5225 dserv, "(", dport, dserv, ")");
5226 ssh2_pkt_init(ssh, SSH2_MSG_GLOBAL_REQUEST);
5227 ssh2_pkt_addstring(ssh, "tcpip-forward");
5228 ssh2_pkt_addbool(ssh, 1);/* want reply */
5229 if (*saddr)
5230 ssh2_pkt_addstring(ssh, saddr);
5231 if (cfg.rport_acceptall)
5232 ssh2_pkt_addstring(ssh, "0.0.0.0");
5233 else
5234 ssh2_pkt_addstring(ssh, "127.0.0.1");
5235 ssh2_pkt_adduint32(ssh, sport);
5236 ssh2_pkt_send(ssh);
5237
5238 do {
5239 crWaitUntilV(ispkt);
5240 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5241 unsigned i = ssh2_pkt_getuint32(ssh);
5242 struct ssh_channel *c;
5243 c = find234(ssh->channels, &i, ssh_channelfind);
5244 if (!c)
5245 continue;/* nonexistent channel */
5246 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5247 }
5248 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5249
5250 if (ssh->pktin.type != SSH2_MSG_REQUEST_SUCCESS) {
5251 if (ssh->pktin.type != SSH2_MSG_REQUEST_FAILURE) {
5252 bombout((ssh,"Unexpected response to port "
5253 "forwarding request: packet type %d",
5254 ssh->pktin.type));
5255 crReturnV;
5256 }
5257 logevent("Server refused this port forwarding");
5258 } else {
5259 logevent("Remote port forwarding enabled");
5260 }
5261 }
5262 }
5263 }
5264 }
5265 }
5266
5267 /*
5268 * Potentially enable agent forwarding.
5269 */
5270 if (cfg.agentfwd && agent_exists()) {
5271 logevent("Requesting OpenSSH-style agent forwarding");
5272 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5273 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
5274 ssh2_pkt_addstring(ssh, "auth-agent-req@openssh.com");
5275 ssh2_pkt_addbool(ssh, 1); /* want reply */
5276 ssh2_pkt_send(ssh);
5277
5278 do {
5279 crWaitUntilV(ispkt);
5280 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5281 unsigned i = ssh2_pkt_getuint32(ssh);
5282 struct ssh_channel *c;
5283 c = find234(ssh->channels, &i, ssh_channelfind);
5284 if (!c)
5285 continue; /* nonexistent channel */
5286 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5287 }
5288 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5289
5290 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5291 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5292 bombout((ssh,"Unexpected response to agent forwarding request:"
5293 " packet type %d", ssh->pktin.type));
5294 crReturnV;
5295 }
5296 logevent("Agent forwarding refused");
5297 } else {
5298 logevent("Agent forwarding enabled");
5299 ssh->agentfwd_enabled = TRUE;
5300 }
5301 }
5302
5303 /*
5304 * Now allocate a pty for the session.
5305 */
5306 if (!cfg.nopty) {
5307 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5308 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid); /* recipient channel */
5309 ssh2_pkt_addstring(ssh, "pty-req");
5310 ssh2_pkt_addbool(ssh, 1); /* want reply */
5311 ssh2_pkt_addstring(ssh, cfg.termtype);
5312 ssh2_pkt_adduint32(ssh, ssh->term_width);
5313 ssh2_pkt_adduint32(ssh, ssh->term_height);
5314 ssh2_pkt_adduint32(ssh, 0); /* pixel width */
5315 ssh2_pkt_adduint32(ssh, 0); /* pixel height */
5316 ssh2_pkt_addstring_start(ssh);
5317 ssh2_pkt_addstring_data(ssh, "\0", 1); /* TTY_OP_END, no special options */
5318 ssh2_pkt_send(ssh);
5319 ssh->state = SSH_STATE_INTERMED;
5320
5321 do {
5322 crWaitUntilV(ispkt);
5323 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5324 unsigned i = ssh2_pkt_getuint32(ssh);
5325 struct ssh_channel *c;
5326 c = find234(ssh->channels, &i, ssh_channelfind);
5327 if (!c)
5328 continue; /* nonexistent channel */
5329 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5330 }
5331 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5332
5333 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5334 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5335 bombout((ssh,"Unexpected response to pty request:"
5336 " packet type %d", ssh->pktin.type));
5337 crReturnV;
5338 }
5339 c_write_str(ssh, "Server refused to allocate pty\r\n");
5340 ssh->editing = ssh->echoing = 1;
5341 } else {
5342 logevent("Allocated pty");
5343 }
5344 } else {
5345 ssh->editing = ssh->echoing = 1;
5346 }
5347
5348 /*
5349 * Start a shell or a remote command. We may have to attempt
5350 * this twice if the config data has provided a second choice
5351 * of command.
5352 */
5353 while (1) {
5354 int subsys;
5355 char *cmd;
5356
5357 if (ssh->fallback_cmd) {
5358 subsys = cfg.ssh_subsys2;
5359 cmd = cfg.remote_cmd_ptr2;
5360 } else {
5361 subsys = cfg.ssh_subsys;
5362 cmd = cfg.remote_cmd_ptr;
5363 }
5364
5365 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5366 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid); /* recipient channel */
5367 if (subsys) {
5368 ssh2_pkt_addstring(ssh, "subsystem");
5369 ssh2_pkt_addbool(ssh, 1); /* want reply */
5370 ssh2_pkt_addstring(ssh, cmd);
5371 } else if (*cmd) {
5372 ssh2_pkt_addstring(ssh, "exec");
5373 ssh2_pkt_addbool(ssh, 1); /* want reply */
5374 ssh2_pkt_addstring(ssh, cmd);
5375 } else {
5376 ssh2_pkt_addstring(ssh, "shell");
5377 ssh2_pkt_addbool(ssh, 1); /* want reply */
5378 }
5379 ssh2_pkt_send(ssh);
5380 do {
5381 crWaitUntilV(ispkt);
5382 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5383 unsigned i = ssh2_pkt_getuint32(ssh);
5384 struct ssh_channel *c;
5385 c = find234(ssh->channels, &i, ssh_channelfind);
5386 if (!c)
5387 continue; /* nonexistent channel */
5388 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5389 }
5390 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5391 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5392 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5393 bombout((ssh,"Unexpected response to shell/command request:"
5394 " packet type %d", ssh->pktin.type));
5395 crReturnV;
5396 }
5397 /*
5398 * We failed to start the command. If this is the
5399 * fallback command, we really are finished; if it's
5400 * not, and if the fallback command exists, try falling
5401 * back to it before complaining.
5402 */
5403 if (!ssh->fallback_cmd && cfg.remote_cmd_ptr2 != NULL) {
5404 logevent("Primary command failed; attempting fallback");
5405 ssh->fallback_cmd = TRUE;
5406 continue;
5407 }
5408 bombout((ssh,"Server refused to start a shell/command"));
5409 crReturnV;
5410 } else {
5411 logevent("Started a shell/command");
5412 }
5413 break;
5414 }
5415
5416 ssh->state = SSH_STATE_SESSION;
5417 if (ssh->size_needed)
5418 ssh_size(ssh, ssh->term_width, ssh->term_height);
5419 if (ssh->eof_needed)
5420 ssh_special(ssh, TS_EOF);
5421
5422 /*
5423 * Transfer data!
5424 */
5425 if (ssh->ldisc)
5426 ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */
5427 ssh->send_ok = 1;
5428 while (1) {
5429 crReturnV;
5430 s->try_send = FALSE;
5431 if (ispkt) {
5432 if (ssh->pktin.type == SSH2_MSG_CHANNEL_DATA ||
5433 ssh->pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA) {
5434 char *data;
5435 int length;
5436 unsigned i = ssh2_pkt_getuint32(ssh);
5437 struct ssh_channel *c;
5438 c = find234(ssh->channels, &i, ssh_channelfind);
5439 if (!c)
5440 continue; /* nonexistent channel */
5441 if (ssh->pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
5442 ssh2_pkt_getuint32(ssh) != SSH2_EXTENDED_DATA_STDERR)
5443 continue; /* extended but not stderr */
5444 ssh2_pkt_getstring(ssh, &data, &length);
5445 if (data) {
5446 int bufsize;
5447 c->v.v2.locwindow -= length;
5448 switch (c->type) {
5449 case CHAN_MAINSESSION:
5450 bufsize =
5451 from_backend(ssh->frontend, ssh->pktin.type ==
5452 SSH2_MSG_CHANNEL_EXTENDED_DATA,
5453 data, length);
5454 break;
5455 case CHAN_X11:
5456 bufsize = x11_send(c->u.x11.s, data, length);
5457 break;
5458 case CHAN_SOCKDATA:
5459 bufsize = pfd_send(c->u.pfd.s, data, length);
5460 break;
5461 case CHAN_AGENT:
5462 while (length > 0) {
5463 if (c->u.a.lensofar < 4) {
5464 int l = min(4 - c->u.a.lensofar, length);
5465 memcpy(c->u.a.msglen + c->u.a.lensofar,
5466 data, l);
5467 data += l;
5468 length -= l;
5469 c->u.a.lensofar += l;
5470 }
5471 if (c->u.a.lensofar == 4) {
5472 c->u.a.totallen =
5473 4 + GET_32BIT(c->u.a.msglen);
5474 c->u.a.message = smalloc(c->u.a.totallen);
5475 memcpy(c->u.a.message, c->u.a.msglen, 4);
5476 }
5477 if (c->u.a.lensofar >= 4 && length > 0) {
5478 int l =
5479 min(c->u.a.totallen - c->u.a.lensofar,
5480 length);
5481 memcpy(c->u.a.message + c->u.a.lensofar,
5482 data, l);
5483 data += l;
5484 length -= l;
5485 c->u.a.lensofar += l;
5486 }
5487 if (c->u.a.lensofar == c->u.a.totallen) {
5488 void *reply, *sentreply;
5489 int replylen;
5490 agent_query(c->u.a.message,
5491 c->u.a.totallen, &reply,
5492 &replylen);
5493 if (reply)
5494 sentreply = reply;
5495 else {
5496 /* Fake SSH_AGENT_FAILURE. */
5497 sentreply = "\0\0\0\1\5";
5498 replylen = 5;
5499 }
5500 ssh2_add_channel_data(c, sentreply, replylen);
5501 s->try_send = TRUE;
5502 if (reply)
5503 sfree(reply);
5504 sfree(c->u.a.message);
5505 c->u.a.lensofar = 0;
5506 }
5507 }
5508 bufsize = 0;
5509 break;
5510 }
5511 /*
5512 * If we are not buffering too much data,
5513 * enlarge the window again at the remote side.
5514 */
5515 if (bufsize < OUR_V2_WINSIZE)
5516 ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
5517 }
5518 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_EOF) {
5519 unsigned i = ssh2_pkt_getuint32(ssh);
5520 struct ssh_channel *c;
5521
5522 c = find234(ssh->channels, &i, ssh_channelfind);
5523 if (!c)
5524 continue; /* nonexistent channel */
5525
5526 if (c->type == CHAN_X11) {
5527 /*
5528 * Remote EOF on an X11 channel means we should
5529 * wrap up and close the channel ourselves.
5530 */
5531 x11_close(c->u.x11.s);
5532 sshfwd_close(c);
5533 } else if (c->type == CHAN_AGENT) {
5534 sshfwd_close(c);
5535 } else if (c->type == CHAN_SOCKDATA) {
5536 pfd_close(c->u.pfd.s);
5537 sshfwd_close(c);
5538 }
5539 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_CLOSE) {
5540 unsigned i = ssh2_pkt_getuint32(ssh);
5541 struct ssh_channel *c;
5542
5543 c = find234(ssh->channels, &i, ssh_channelfind);
5544 if (!c || ((int)c->remoteid) == -1) {
5545 bombout((ssh,"Received CHANNEL_CLOSE for %s channel %d\n",
5546 c ? "half-open" : "nonexistent", i));
5547 }
5548 /* Do pre-close processing on the channel. */
5549 switch (c->type) {
5550 case CHAN_MAINSESSION:
5551 break; /* nothing to see here, move along */
5552 case CHAN_X11:
5553 if (c->u.x11.s != NULL)
5554 x11_close(c->u.x11.s);
5555 sshfwd_close(c);
5556 break;
5557 case CHAN_AGENT:
5558 sshfwd_close(c);
5559 break;
5560 case CHAN_SOCKDATA:
5561 if (c->u.pfd.s != NULL)
5562 pfd_close(c->u.pfd.s);
5563 sshfwd_close(c);
5564 break;
5565 }
5566 if (c->closes == 0) {
5567 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
5568 ssh2_pkt_adduint32(ssh, c->remoteid);
5569 ssh2_pkt_send(ssh);
5570 }
5571 del234(ssh->channels, c);
5572 bufchain_clear(&c->v.v2.outbuffer);
5573 sfree(c);
5574
5575 /*
5576 * See if that was the last channel left open.
5577 */
5578 if (count234(ssh->channels) == 0) {
5579 #if 0
5580 /*
5581 * We used to send SSH_MSG_DISCONNECT here,
5582 * because I'd believed that _every_ conforming
5583 * SSH2 connection had to end with a disconnect
5584 * being sent by at least one side; apparently
5585 * I was wrong and it's perfectly OK to
5586 * unceremoniously slam the connection shut
5587 * when you're done, and indeed OpenSSH feels
5588 * this is more polite than sending a
5589 * DISCONNECT. So now we don't.
5590 */
5591 logevent("All channels closed. Disconnecting");
5592 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5593 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5594 ssh2_pkt_addstring(ssh, "All open channels closed");
5595 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5596 ssh2_pkt_send(ssh);
5597 #endif
5598 ssh->state = SSH_STATE_CLOSED;
5599 crReturnV;
5600 }
5601 continue; /* remote sends close; ignore (FIXME) */
5602 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5603 unsigned i = ssh2_pkt_getuint32(ssh);
5604 struct ssh_channel *c;
5605 c = find234(ssh->channels, &i, ssh_channelfind);
5606 if (!c)
5607 continue; /* nonexistent channel */
5608 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5609 s->try_send = TRUE;
5610 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
5611 unsigned i = ssh2_pkt_getuint32(ssh);
5612 struct ssh_channel *c;
5613 c = find234(ssh->channels, &i, ssh_channelfind);
5614 if (!c)
5615 continue; /* nonexistent channel */
5616 if (c->type != CHAN_SOCKDATA_DORMANT)
5617 continue; /* dunno why they're confirming this */
5618 c->remoteid = ssh2_pkt_getuint32(ssh);
5619 c->type = CHAN_SOCKDATA;
5620 c->v.v2.remwindow = ssh2_pkt_getuint32(ssh);
5621 c->v.v2.remmaxpkt = ssh2_pkt_getuint32(ssh);
5622 if (c->u.pfd.s)
5623 pfd_confirm(c->u.pfd.s);
5624 if (c->closes) {
5625 /*
5626 * We have a pending close on this channel,
5627 * which we decided on before the server acked
5628 * the channel open. So now we know the
5629 * remoteid, we can close it again.
5630 */
5631 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
5632 ssh2_pkt_adduint32(ssh, c->remoteid);
5633 ssh2_pkt_send(ssh);
5634 }
5635 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN_FAILURE) {
5636 unsigned i = ssh2_pkt_getuint32(ssh);
5637 struct ssh_channel *c;
5638 c = find234(ssh->channels, &i, ssh_channelfind);
5639 if (!c)
5640 continue; /* nonexistent channel */
5641 if (c->type != CHAN_SOCKDATA_DORMANT)
5642 continue; /* dunno why they're failing this */
5643
5644 logevent("Forwarded connection refused by server");
5645
5646 pfd_close(c->u.pfd.s);
5647
5648 del234(ssh->channels, c);
5649 sfree(c);
5650 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_REQUEST) {
5651 unsigned localid;
5652 char *type;
5653 int typelen, want_reply;
5654 struct ssh_channel *c;
5655
5656 localid = ssh2_pkt_getuint32(ssh);
5657 ssh2_pkt_getstring(ssh, &type, &typelen);
5658 want_reply = ssh2_pkt_getbool(ssh);
5659
5660 /*
5661 * First, check that the channel exists. Otherwise,
5662 * we can instantly disconnect with a rude message.
5663 */
5664 c = find234(ssh->channels, &localid, ssh_channelfind);
5665 if (!c) {
5666 char buf[80];
5667 sprintf(buf, "Received channel request for nonexistent"
5668 " channel %d", localid);
5669 logevent(buf);
5670 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5671 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5672 ssh2_pkt_addstring(ssh, buf);
5673 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5674 ssh2_pkt_send(ssh);
5675 connection_fatal("%s", buf);
5676 ssh->state = SSH_STATE_CLOSED;
5677 crReturnV;
5678 }
5679
5680 /*
5681 * Having got the channel number, we now look at
5682 * the request type string to see if it's something
5683 * we recognise.
5684 */
5685 if (typelen == 11 && !memcmp(type, "exit-status", 11) &&
5686 c == ssh->mainchan) {
5687 /* We recognise "exit-status" on the primary channel. */
5688 char buf[100];
5689 ssh->exitcode = ssh2_pkt_getuint32(ssh);
5690 sprintf(buf, "Server sent command exit status %d",
5691 ssh->exitcode);
5692 logevent(buf);
5693 if (want_reply) {
5694 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_SUCCESS);
5695 ssh2_pkt_adduint32(ssh, c->remoteid);
5696 ssh2_pkt_send(ssh);
5697 }
5698 } else {
5699 /*
5700 * This is a channel request we don't know
5701 * about, so we now either ignore the request
5702 * or respond with CHANNEL_FAILURE, depending
5703 * on want_reply.
5704 */
5705 if (want_reply) {
5706 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_FAILURE);
5707 ssh2_pkt_adduint32(ssh, c->remoteid);
5708 ssh2_pkt_send(ssh);
5709 }
5710 }
5711 } else if (ssh->pktin.type == SSH2_MSG_GLOBAL_REQUEST) {
5712 char *type;
5713 int typelen, want_reply;
5714
5715 ssh2_pkt_getstring(ssh, &type, &typelen);
5716 want_reply = ssh2_pkt_getbool(ssh);
5717
5718 /*
5719 * We currently don't support any global requests
5720 * at all, so we either ignore the request or
5721 * respond with REQUEST_FAILURE, depending on
5722 * want_reply.
5723 */
5724 if (want_reply) {
5725 ssh2_pkt_init(ssh, SSH2_MSG_REQUEST_FAILURE);
5726 ssh2_pkt_send(ssh);
5727 }
5728 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN) {
5729 char *type;
5730 int typelen;
5731 char *error = NULL;
5732 struct ssh_channel *c;
5733 unsigned remid, winsize, pktsize;
5734 ssh2_pkt_getstring(ssh, &type, &typelen);
5735 c = smalloc(sizeof(struct ssh_channel));
5736 c->ssh = ssh;
5737
5738 remid = ssh2_pkt_getuint32(ssh);
5739 winsize = ssh2_pkt_getuint32(ssh);
5740 pktsize = ssh2_pkt_getuint32(ssh);
5741
5742 if (typelen == 3 && !memcmp(type, "x11", 3)) {
5743 if (!ssh->X11_fwd_enabled)
5744 error = "X11 forwarding is not enabled";
5745 else if (x11_init(&c->u.x11.s, cfg.x11_display, c,
5746 ssh->x11auth) != NULL) {
5747 error = "Unable to open an X11 connection";
5748 } else {
5749 c->type = CHAN_X11;
5750 }
5751 } else if (typelen == 15 &&
5752 !memcmp(type, "forwarded-tcpip", 15)) {
5753 struct ssh_rportfwd pf, *realpf;
5754 char *dummy;
5755 int dummylen;
5756 ssh2_pkt_getstring(ssh, &dummy, &dummylen);/* skip address */
5757 pf.sport = ssh2_pkt_getuint32(ssh);
5758 realpf = find234(ssh->rportfwds, &pf, NULL);
5759 if (realpf == NULL) {
5760 error = "Remote port is not recognised";
5761 } else {
5762 char *e = pfd_newconnect(&c->u.pfd.s, realpf->dhost,
5763 realpf->dport, c);
5764 logeventf(ssh, "Received remote port open request"
5765 " for %s:%d", realpf->dhost, realpf->dport);
5766 if (e != NULL) {
5767 logeventf(ssh, "Port open failed: %s", e);
5768 error = "Port open failed";
5769 } else {
5770 logevent("Forwarded port opened successfully");
5771 c->type = CHAN_SOCKDATA;
5772 }
5773 }
5774 } else if (typelen == 22 &&
5775 !memcmp(type, "auth-agent@openssh.com", 3)) {
5776 if (!ssh->agentfwd_enabled)
5777 error = "Agent forwarding is not enabled";
5778 else {
5779 c->type = CHAN_AGENT; /* identify channel type */
5780 c->u.a.lensofar = 0;
5781 }
5782 } else {
5783 error = "Unsupported channel type requested";
5784 }
5785
5786 c->remoteid = remid;
5787 if (error) {
5788 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN_FAILURE);
5789 ssh2_pkt_adduint32(ssh, c->remoteid);
5790 ssh2_pkt_adduint32(ssh, SSH2_OPEN_CONNECT_FAILED);
5791 ssh2_pkt_addstring(ssh, error);
5792 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5793 ssh2_pkt_send(ssh);
5794 sfree(c);
5795 } else {
5796 c->localid = alloc_channel_id(ssh);
5797 c->closes = 0;
5798 c->v.v2.locwindow = OUR_V2_WINSIZE;
5799 c->v.v2.remwindow = winsize;
5800 c->v.v2.remmaxpkt = pktsize;
5801 bufchain_init(&c->v.v2.outbuffer);
5802 add234(ssh->channels, c);
5803 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
5804 ssh2_pkt_adduint32(ssh, c->remoteid);
5805 ssh2_pkt_adduint32(ssh, c->localid);
5806 ssh2_pkt_adduint32(ssh, c->v.v2.locwindow);
5807 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
5808 ssh2_pkt_send(ssh);
5809 }
5810 } else {
5811 bombout((ssh,"Strange packet received: type %d", ssh->pktin.type));
5812 crReturnV;
5813 }
5814 } else {
5815 /*
5816 * We have spare data. Add it to the channel buffer.
5817 */
5818 ssh2_add_channel_data(ssh->mainchan, (char *)in, inlen);
5819 s->try_send = TRUE;
5820 }
5821 if (s->try_send) {
5822 int i;
5823 struct ssh_channel *c;
5824 /*
5825 * Try to send data on all channels if we can.
5826 */
5827 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
5828 int bufsize = ssh2_try_send(c);
5829 if (bufsize == 0) {
5830 switch (c->type) {
5831 case CHAN_MAINSESSION:
5832 /* stdin need not receive an unthrottle
5833 * notification since it will be polled */
5834 break;
5835 case CHAN_X11:
5836 x11_unthrottle(c->u.x11.s);
5837 break;
5838 case CHAN_AGENT:
5839 /* agent sockets are request/response and need no
5840 * buffer management */
5841 break;
5842 case CHAN_SOCKDATA:
5843 pfd_unthrottle(c->u.pfd.s);
5844 break;
5845 }
5846 }
5847 }
5848 }
5849 }
5850
5851 crFinishV;
5852 }
5853
5854 /*
5855 * Handle the top-level SSH2 protocol.
5856 */
5857 static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
5858 {
5859 if (do_ssh2_transport(ssh, in, inlen, ispkt) == 0)
5860 return;
5861 do_ssh2_authconn(ssh, in, inlen, ispkt);
5862 }
5863
5864 /*
5865 * Called to set up the connection.
5866 *
5867 * Returns an error message, or NULL on success.
5868 */
5869 static char *ssh_init(void *frontend_handle, void **backend_handle,
5870 char *host, int port, char **realhost, int nodelay)
5871 {
5872 char *p;
5873 Ssh ssh;
5874
5875 ssh = smalloc(sizeof(*ssh));
5876 ssh->s = NULL;
5877 ssh->cipher = NULL;
5878 ssh->v1_cipher_ctx = NULL;
5879 ssh->crcda_ctx = NULL;
5880 ssh->cscipher = NULL;
5881 ssh->cs_cipher_ctx = NULL;
5882 ssh->sccipher = NULL;
5883 ssh->sc_cipher_ctx = NULL;
5884 ssh->csmac = NULL;
5885 ssh->cs_mac_ctx = NULL;
5886 ssh->scmac = NULL;
5887 ssh->sc_mac_ctx = NULL;
5888 ssh->cscomp = NULL;
5889 ssh->cs_comp_ctx = NULL;
5890 ssh->sccomp = NULL;
5891 ssh->sc_comp_ctx = NULL;
5892 ssh->kex = NULL;
5893 ssh->hostkey = NULL;
5894 ssh->exitcode = -1;
5895 ssh->state = SSH_STATE_PREPACKET;
5896 ssh->size_needed = FALSE;
5897 ssh->eof_needed = FALSE;
5898 ssh->ldisc = NULL;
5899 ssh->logctx = NULL;
5900 {
5901 static const struct Packet empty = { 0, 0, NULL, NULL, 0 };
5902 ssh->pktin = ssh->pktout = empty;
5903 }
5904 ssh->deferred_send_data = NULL;
5905 ssh->deferred_len = 0;
5906 ssh->deferred_size = 0;
5907 ssh->fallback_cmd = 0;
5908 ssh->pkt_ctx = 0;
5909 ssh->x11auth = NULL;
5910 ssh->v1_compressing = FALSE;
5911 ssh->v2_outgoing_sequence = 0;
5912 ssh->ssh1_rdpkt_crstate = 0;
5913 ssh->ssh2_rdpkt_crstate = 0;
5914 ssh->do_ssh_init_crstate = 0;
5915 ssh->ssh_gotdata_crstate = 0;
5916 ssh->ssh1_protocol_crstate = 0;
5917 ssh->do_ssh1_login_crstate = 0;
5918 ssh->do_ssh2_transport_crstate = 0;
5919 ssh->do_ssh2_authconn_crstate = 0;
5920 ssh->do_ssh_init_state = NULL;
5921 ssh->do_ssh1_login_state = NULL;
5922 ssh->do_ssh2_transport_state = NULL;
5923 ssh->do_ssh2_authconn_state = NULL;
5924 ssh->mainchan = NULL;
5925 ssh->throttled_all = 0;
5926 ssh->v1_stdout_throttling = 0;
5927
5928 *backend_handle = ssh;
5929
5930 #ifdef MSCRYPTOAPI
5931 if (crypto_startup() == 0)
5932 return "Microsoft high encryption pack not installed!";
5933 #endif
5934
5935 ssh->frontend = frontend_handle;
5936 ssh->term_width = cfg.width;
5937 ssh->term_height = cfg.height;
5938
5939 ssh->send_ok = 0;
5940 ssh->editing = 0;
5941 ssh->echoing = 0;
5942 ssh->v1_throttle_count = 0;
5943 ssh->overall_bufsize = 0;
5944 ssh->fallback_cmd = 0;
5945
5946 p = connect_to_host(ssh, host, port, realhost, nodelay);
5947 if (p != NULL)
5948 return p;
5949
5950 return NULL;
5951 }
5952
5953 /*
5954 * Called to send data down the Telnet connection.
5955 */
5956 static int ssh_send(void *handle, char *buf, int len)
5957 {
5958 Ssh ssh = (Ssh) handle;
5959
5960 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
5961 return 0;
5962
5963 ssh->protocol(ssh, (unsigned char *)buf, len, 0);
5964
5965 return ssh_sendbuffer(ssh);
5966 }
5967
5968 /*
5969 * Called to query the current amount of buffered stdin data.
5970 */
5971 static int ssh_sendbuffer(void *handle)
5972 {
5973 Ssh ssh = (Ssh) handle;
5974 int override_value;
5975
5976 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
5977 return 0;
5978
5979 /*
5980 * If the SSH socket itself has backed up, add the total backup
5981 * size on that to any individual buffer on the stdin channel.
5982 */
5983 override_value = 0;
5984 if (ssh->throttled_all)
5985 override_value = ssh->overall_bufsize;
5986
5987 if (ssh->version == 1) {
5988 return override_value;
5989 } else if (ssh->version == 2) {
5990 if (!ssh->mainchan || ssh->mainchan->closes > 0)
5991 return override_value;
5992 else
5993 return (override_value +
5994 bufchain_size(&ssh->mainchan->v.v2.outbuffer));
5995 }
5996
5997 return 0;
5998 }
5999
6000 /*
6001 * Called to set the size of the window from SSH's POV.
6002 */
6003 static void ssh_size(void *handle, int width, int height)
6004 {
6005 Ssh ssh = (Ssh) handle;
6006
6007 ssh->term_width = width;
6008 ssh->term_height = height;
6009
6010 switch (ssh->state) {
6011 case SSH_STATE_BEFORE_SIZE:
6012 case SSH_STATE_PREPACKET:
6013 case SSH_STATE_CLOSED:
6014 break; /* do nothing */
6015 case SSH_STATE_INTERMED:
6016 ssh->size_needed = TRUE; /* buffer for later */
6017 break;
6018 case SSH_STATE_SESSION:
6019 if (!cfg.nopty) {
6020 if (ssh->version == 1) {
6021 send_packet(ssh, SSH1_CMSG_WINDOW_SIZE,
6022 PKT_INT, ssh->term_height,
6023 PKT_INT, ssh->term_width,
6024 PKT_INT, 0, PKT_INT, 0, PKT_END);
6025 } else {
6026 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
6027 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
6028 ssh2_pkt_addstring(ssh, "window-change");
6029 ssh2_pkt_addbool(ssh, 0);
6030 ssh2_pkt_adduint32(ssh, ssh->term_width);
6031 ssh2_pkt_adduint32(ssh, ssh->term_height);
6032 ssh2_pkt_adduint32(ssh, 0);
6033 ssh2_pkt_adduint32(ssh, 0);
6034 ssh2_pkt_send(ssh);
6035 }
6036 }
6037 break;
6038 }
6039 }
6040
6041 /*
6042 * Send Telnet special codes. TS_EOF is useful for `plink', so you
6043 * can send an EOF and collect resulting output (e.g. `plink
6044 * hostname sort').
6045 */
6046 static void ssh_special(void *handle, Telnet_Special code)
6047 {
6048 Ssh ssh = (Ssh) handle;
6049
6050 if (code == TS_EOF) {
6051 if (ssh->state != SSH_STATE_SESSION) {
6052 /*
6053 * Buffer the EOF in case we are pre-SESSION, so we can
6054 * send it as soon as we reach SESSION.
6055 */
6056 if (code == TS_EOF)
6057 ssh->eof_needed = TRUE;
6058 return;
6059 }
6060 if (ssh->version == 1) {
6061 send_packet(ssh, SSH1_CMSG_EOF, PKT_END);
6062 } else {
6063 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_EOF);
6064 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
6065 ssh2_pkt_send(ssh);
6066 }
6067 logevent("Sent EOF message");
6068 } else if (code == TS_PING) {
6069 if (ssh->state == SSH_STATE_CLOSED
6070 || ssh->state == SSH_STATE_PREPACKET) return;
6071 if (ssh->version == 1) {
6072 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE))
6073 send_packet(ssh, SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
6074 } else {
6075 ssh2_pkt_init(ssh, SSH2_MSG_IGNORE);
6076 ssh2_pkt_addstring_start(ssh);
6077 ssh2_pkt_send(ssh);
6078 }
6079 } else {
6080 /* do nothing */
6081 }
6082 }
6083
6084 void *new_sock_channel(void *handle, Socket s)
6085 {
6086 Ssh ssh = (Ssh) handle;
6087 struct ssh_channel *c;
6088 c = smalloc(sizeof(struct ssh_channel));
6089 c->ssh = ssh;
6090
6091 if (c) {
6092 c->remoteid = -1; /* to be set when open confirmed */
6093 c->localid = alloc_channel_id(ssh);
6094 c->closes = 0;
6095 c->type = CHAN_SOCKDATA_DORMANT;/* identify channel type */
6096 c->u.pfd.s = s;
6097 bufchain_init(&c->v.v2.outbuffer);
6098 add234(ssh->channels, c);
6099 }
6100 return c;
6101 }
6102
6103 /*
6104 * This is called when stdout/stderr (the entity to which
6105 * from_backend sends data) manages to clear some backlog.
6106 */
6107 void ssh_unthrottle(void *handle, int bufsize)
6108 {
6109 Ssh ssh = (Ssh) handle;
6110 if (ssh->version == 1) {
6111 if (ssh->v1_stdout_throttling && bufsize < SSH1_BUFFER_LIMIT) {
6112 ssh->v1_stdout_throttling = 0;
6113 ssh1_throttle(ssh, -1);
6114 }
6115 } else {
6116 if (ssh->mainchan && ssh->mainchan->closes == 0)
6117 ssh2_set_window(ssh->mainchan, OUR_V2_WINSIZE - bufsize);
6118 }
6119 }
6120
6121 void ssh_send_port_open(void *channel, char *hostname, int port, char *org)
6122 {
6123 struct ssh_channel *c = (struct ssh_channel *)channel;
6124 Ssh ssh = c->ssh;
6125
6126 logeventf(ssh, "Opening forwarded connection to %s:%d", hostname, port);
6127
6128 if (ssh->version == 1) {
6129 send_packet(ssh, SSH1_MSG_PORT_OPEN,
6130 PKT_INT, c->localid,
6131 PKT_STR, hostname,
6132 PKT_INT, port,
6133 //PKT_STR, <org:orgport>,
6134 PKT_END);
6135 } else {
6136 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN);
6137 ssh2_pkt_addstring(ssh, "direct-tcpip");
6138 ssh2_pkt_adduint32(ssh, c->localid);
6139 c->v.v2.locwindow = OUR_V2_WINSIZE;
6140 ssh2_pkt_adduint32(ssh, c->v.v2.locwindow);/* our window size */
6141 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
6142 ssh2_pkt_addstring(ssh, hostname);
6143 ssh2_pkt_adduint32(ssh, port);
6144 /*
6145 * We make up values for the originator data; partly it's
6146 * too much hassle to keep track, and partly I'm not
6147 * convinced the server should be told details like that
6148 * about my local network configuration.
6149 */
6150 ssh2_pkt_addstring(ssh, "client-side-connection");
6151 ssh2_pkt_adduint32(ssh, 0);
6152 ssh2_pkt_send(ssh);
6153 }
6154 }
6155
6156
6157 static Socket ssh_socket(void *handle)
6158 {
6159 Ssh ssh = (Ssh) handle;
6160 return ssh->s;
6161 }
6162
6163 static int ssh_sendok(void *handle)
6164 {
6165 Ssh ssh = (Ssh) handle;
6166 return ssh->send_ok;
6167 }
6168
6169 static int ssh_ldisc(void *handle, int option)
6170 {
6171 Ssh ssh = (Ssh) handle;
6172 if (option == LD_ECHO)
6173 return ssh->echoing;
6174 if (option == LD_EDIT)
6175 return ssh->editing;
6176 return FALSE;
6177 }
6178
6179 static void ssh_provide_ldisc(void *handle, void *ldisc)
6180 {
6181 Ssh ssh = (Ssh) handle;
6182 ssh->ldisc = ldisc;
6183 }
6184
6185 static void ssh_provide_logctx(void *handle, void *logctx)
6186 {
6187 Ssh ssh = (Ssh) handle;
6188 ssh->logctx = logctx;
6189 }
6190
6191 static int ssh_return_exitcode(void *handle)
6192 {
6193 Ssh ssh = (Ssh) handle;
6194 return ssh->exitcode;
6195 }
6196
6197 /*
6198 * Gross hack: pscp will try to start SFTP but fall back to scp1 if
6199 * that fails. This variable is the means by which scp.c can reach
6200 * into the SSH code and find out which one it got.
6201 */
6202 extern int ssh_fallback_cmd(void *handle)
6203 {
6204 Ssh ssh = (Ssh) handle;
6205 return ssh->fallback_cmd;
6206 }
6207
6208 Backend ssh_backend = {
6209 ssh_init,
6210 ssh_send,
6211 ssh_sendbuffer,
6212 ssh_size,
6213 ssh_special,
6214 ssh_socket,
6215 ssh_return_exitcode,
6216 ssh_sendok,
6217 ssh_ldisc,
6218 ssh_provide_ldisc,
6219 ssh_provide_logctx,
6220 ssh_unthrottle,
6221 22
6222 };
Local modifications for Simon Tatham's `PuTTY' SSH client and terminal emulator