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1 | /* $OpenBSD: packet.c,v 1.166 2009/06/27 09:29:06 andreas Exp $ */ | |
2 | /* | |
3 | * Author: Tatu Ylonen <ylo@cs.hut.fi> | |
4 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland | |
5 | * All rights reserved | |
6 | * This file contains code implementing the packet protocol and communication | |
7 | * with the other side. This same code is used both on client and server side. | |
8 | * | |
9 | * As far as I am concerned, the code I have written for this software | |
10 | * can be used freely for any purpose. Any derived versions of this | |
11 | * software must be clearly marked as such, and if the derived work is | |
12 | * incompatible with the protocol description in the RFC file, it must be | |
13 | * called by a name other than "ssh" or "Secure Shell". | |
14 | * | |
15 | * | |
16 | * SSH2 packet format added by Markus Friedl. | |
17 | * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. | |
18 | * | |
19 | * Redistribution and use in source and binary forms, with or without | |
20 | * modification, are permitted provided that the following conditions | |
21 | * are met: | |
22 | * 1. Redistributions of source code must retain the above copyright | |
23 | * notice, this list of conditions and the following disclaimer. | |
24 | * 2. Redistributions in binary form must reproduce the above copyright | |
25 | * notice, this list of conditions and the following disclaimer in the | |
26 | * documentation and/or other materials provided with the distribution. | |
27 | * | |
28 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR | |
29 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES | |
30 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. | |
31 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, | |
32 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
33 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
34 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
35 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
36 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | |
37 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
38 | */ | |
39 | ||
40 | #include "includes.h" | |
41 | ||
42 | #include <sys/types.h> | |
43 | #include "openbsd-compat/sys-queue.h" | |
44 | #include <sys/param.h> | |
45 | #include <sys/socket.h> | |
46 | #ifdef HAVE_SYS_TIME_H | |
47 | # include <sys/time.h> | |
48 | #endif | |
49 | ||
50 | #include <netinet/in.h> | |
51 | #include <netinet/ip.h> | |
52 | #include <arpa/inet.h> | |
53 | ||
54 | #include <errno.h> | |
55 | #include <stdarg.h> | |
56 | #include <stdio.h> | |
57 | #include <stdlib.h> | |
58 | #include <string.h> | |
59 | #include <unistd.h> | |
60 | #include <signal.h> | |
61 | ||
62 | #include "xmalloc.h" | |
63 | #include "buffer.h" | |
64 | #include "packet.h" | |
65 | #include "crc32.h" | |
66 | #include "compress.h" | |
67 | #include "deattack.h" | |
68 | #include "channels.h" | |
69 | #include "compat.h" | |
70 | #include "ssh1.h" | |
71 | #include "ssh2.h" | |
72 | #include "cipher.h" | |
73 | #include "key.h" | |
74 | #include "kex.h" | |
75 | #include "mac.h" | |
76 | #include "log.h" | |
77 | #include "canohost.h" | |
78 | #include "misc.h" | |
79 | #include "ssh.h" | |
80 | #include "roaming.h" | |
81 | ||
82 | #ifdef PACKET_DEBUG | |
83 | #define DBG(x) x | |
84 | #else | |
85 | #define DBG(x) | |
86 | #endif | |
87 | ||
88 | #define PACKET_MAX_SIZE (256 * 1024) | |
89 | ||
90 | struct packet_state { | |
91 | u_int32_t seqnr; | |
92 | u_int32_t packets; | |
93 | u_int64_t blocks; | |
94 | u_int64_t bytes; | |
95 | }; | |
96 | ||
97 | struct packet { | |
98 | TAILQ_ENTRY(packet) next; | |
99 | u_char type; | |
100 | Buffer payload; | |
101 | }; | |
102 | ||
103 | struct session_state { | |
104 | /* | |
105 | * This variable contains the file descriptors used for | |
106 | * communicating with the other side. connection_in is used for | |
107 | * reading; connection_out for writing. These can be the same | |
108 | * descriptor, in which case it is assumed to be a socket. | |
109 | */ | |
110 | int connection_in; | |
111 | int connection_out; | |
112 | ||
113 | /* Protocol flags for the remote side. */ | |
114 | u_int remote_protocol_flags; | |
115 | ||
116 | /* Encryption context for receiving data. Only used for decryption. */ | |
117 | CipherContext receive_context; | |
118 | ||
119 | /* Encryption context for sending data. Only used for encryption. */ | |
120 | CipherContext send_context; | |
121 | ||
122 | /* Buffer for raw input data from the socket. */ | |
123 | Buffer input; | |
124 | ||
125 | /* Buffer for raw output data going to the socket. */ | |
126 | Buffer output; | |
127 | ||
128 | /* Buffer for the partial outgoing packet being constructed. */ | |
129 | Buffer outgoing_packet; | |
130 | ||
131 | /* Buffer for the incoming packet currently being processed. */ | |
132 | Buffer incoming_packet; | |
133 | ||
134 | /* Scratch buffer for packet compression/decompression. */ | |
135 | Buffer compression_buffer; | |
136 | int compression_buffer_ready; | |
137 | ||
138 | /* | |
139 | * Flag indicating whether packet compression/decompression is | |
140 | * enabled. | |
141 | */ | |
142 | int packet_compression; | |
143 | ||
144 | /* default maximum packet size */ | |
145 | u_int max_packet_size; | |
146 | ||
147 | /* Flag indicating whether this module has been initialized. */ | |
148 | int initialized; | |
149 | ||
150 | /* Set to true if the connection is interactive. */ | |
151 | int interactive_mode; | |
152 | ||
153 | /* Set to true if we are the server side. */ | |
154 | int server_side; | |
155 | ||
156 | /* Set to true if we are authenticated. */ | |
157 | int after_authentication; | |
158 | ||
159 | int keep_alive_timeouts; | |
160 | ||
161 | /* The maximum time that we will wait to send or receive a packet */ | |
162 | int packet_timeout_ms; | |
163 | ||
164 | /* Session key information for Encryption and MAC */ | |
165 | Newkeys *newkeys[MODE_MAX]; | |
166 | struct packet_state p_read, p_send; | |
167 | ||
168 | u_int64_t max_blocks_in, max_blocks_out; | |
169 | u_int32_t rekey_limit; | |
170 | ||
171 | /* Session key for protocol v1 */ | |
172 | u_char ssh1_key[SSH_SESSION_KEY_LENGTH]; | |
173 | u_int ssh1_keylen; | |
174 | ||
175 | /* roundup current message to extra_pad bytes */ | |
176 | u_char extra_pad; | |
177 | ||
178 | /* XXX discard incoming data after MAC error */ | |
179 | u_int packet_discard; | |
180 | Mac *packet_discard_mac; | |
181 | ||
182 | /* Used in packet_read_poll2() */ | |
183 | u_int packlen; | |
184 | ||
185 | /* Used in packet_send2 */ | |
186 | int rekeying; | |
187 | ||
188 | /* Used in packet_set_interactive */ | |
189 | int set_interactive_called; | |
190 | ||
191 | /* Used in packet_set_maxsize */ | |
192 | int set_maxsize_called; | |
193 | ||
194 | TAILQ_HEAD(, packet) outgoing; | |
195 | }; | |
196 | ||
197 | static struct session_state *active_state, *backup_state; | |
198 | ||
199 | static struct session_state * | |
200 | alloc_session_state(void) | |
201 | { | |
202 | struct session_state *s = xcalloc(1, sizeof(*s)); | |
203 | ||
204 | s->connection_in = -1; | |
205 | s->connection_out = -1; | |
206 | s->max_packet_size = 32768; | |
207 | s->packet_timeout_ms = -1; | |
208 | return s; | |
209 | } | |
210 | ||
211 | /* | |
212 | * Sets the descriptors used for communication. Disables encryption until | |
213 | * packet_set_encryption_key is called. | |
214 | */ | |
215 | void | |
216 | packet_set_connection(int fd_in, int fd_out) | |
217 | { | |
218 | Cipher *none = cipher_by_name("none"); | |
219 | ||
220 | if (none == NULL) | |
221 | fatal("packet_set_connection: cannot load cipher 'none'"); | |
222 | if (active_state == NULL) | |
223 | active_state = alloc_session_state(); | |
224 | active_state->connection_in = fd_in; | |
225 | active_state->connection_out = fd_out; | |
226 | cipher_init(&active_state->send_context, none, (const u_char *)"", | |
227 | 0, NULL, 0, CIPHER_ENCRYPT); | |
228 | cipher_init(&active_state->receive_context, none, (const u_char *)"", | |
229 | 0, NULL, 0, CIPHER_DECRYPT); | |
230 | active_state->newkeys[MODE_IN] = active_state->newkeys[MODE_OUT] = NULL; | |
231 | if (!active_state->initialized) { | |
232 | active_state->initialized = 1; | |
233 | buffer_init(&active_state->input); | |
234 | buffer_init(&active_state->output); | |
235 | buffer_init(&active_state->outgoing_packet); | |
236 | buffer_init(&active_state->incoming_packet); | |
237 | TAILQ_INIT(&active_state->outgoing); | |
238 | active_state->p_send.packets = active_state->p_read.packets = 0; | |
239 | } | |
240 | } | |
241 | ||
242 | void | |
243 | packet_set_timeout(int timeout, int count) | |
244 | { | |
245 | if (timeout == 0 || count == 0) { | |
246 | active_state->packet_timeout_ms = -1; | |
247 | return; | |
248 | } | |
249 | if ((INT_MAX / 1000) / count < timeout) | |
250 | active_state->packet_timeout_ms = INT_MAX; | |
251 | else | |
252 | active_state->packet_timeout_ms = timeout * count * 1000; | |
253 | } | |
254 | ||
255 | static void | |
256 | packet_stop_discard(void) | |
257 | { | |
258 | if (active_state->packet_discard_mac) { | |
259 | char buf[1024]; | |
260 | ||
261 | memset(buf, 'a', sizeof(buf)); | |
262 | while (buffer_len(&active_state->incoming_packet) < | |
263 | PACKET_MAX_SIZE) | |
264 | buffer_append(&active_state->incoming_packet, buf, | |
265 | sizeof(buf)); | |
266 | (void) mac_compute(active_state->packet_discard_mac, | |
267 | active_state->p_read.seqnr, | |
268 | buffer_ptr(&active_state->incoming_packet), | |
269 | PACKET_MAX_SIZE); | |
270 | } | |
271 | logit("Finished discarding for %.200s", get_remote_ipaddr()); | |
272 | cleanup_exit(255); | |
273 | } | |
274 | ||
275 | static void | |
276 | packet_start_discard(Enc *enc, Mac *mac, u_int packet_length, u_int discard) | |
277 | { | |
278 | if (enc == NULL || !cipher_is_cbc(enc->cipher)) | |
279 | packet_disconnect("Packet corrupt"); | |
280 | if (packet_length != PACKET_MAX_SIZE && mac && mac->enabled) | |
281 | active_state->packet_discard_mac = mac; | |
282 | if (buffer_len(&active_state->input) >= discard) | |
283 | packet_stop_discard(); | |
284 | active_state->packet_discard = discard - | |
285 | buffer_len(&active_state->input); | |
286 | } | |
287 | ||
288 | /* Returns 1 if remote host is connected via socket, 0 if not. */ | |
289 | ||
290 | int | |
291 | packet_connection_is_on_socket(void) | |
292 | { | |
293 | struct sockaddr_storage from, to; | |
294 | socklen_t fromlen, tolen; | |
295 | ||
296 | /* filedescriptors in and out are the same, so it's a socket */ | |
297 | if (active_state->connection_in == active_state->connection_out) | |
298 | return 1; | |
299 | fromlen = sizeof(from); | |
300 | memset(&from, 0, sizeof(from)); | |
301 | if (getpeername(active_state->connection_in, (struct sockaddr *)&from, | |
302 | &fromlen) < 0) | |
303 | return 0; | |
304 | tolen = sizeof(to); | |
305 | memset(&to, 0, sizeof(to)); | |
306 | if (getpeername(active_state->connection_out, (struct sockaddr *)&to, | |
307 | &tolen) < 0) | |
308 | return 0; | |
309 | if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0) | |
310 | return 0; | |
311 | if (from.ss_family != AF_INET && from.ss_family != AF_INET6) | |
312 | return 0; | |
313 | return 1; | |
314 | } | |
315 | ||
316 | /* | |
317 | * Exports an IV from the CipherContext required to export the key | |
318 | * state back from the unprivileged child to the privileged parent | |
319 | * process. | |
320 | */ | |
321 | ||
322 | void | |
323 | packet_get_keyiv(int mode, u_char *iv, u_int len) | |
324 | { | |
325 | CipherContext *cc; | |
326 | ||
327 | if (mode == MODE_OUT) | |
328 | cc = &active_state->send_context; | |
329 | else | |
330 | cc = &active_state->receive_context; | |
331 | ||
332 | cipher_get_keyiv(cc, iv, len); | |
333 | } | |
334 | ||
335 | int | |
336 | packet_get_keycontext(int mode, u_char *dat) | |
337 | { | |
338 | CipherContext *cc; | |
339 | ||
340 | if (mode == MODE_OUT) | |
341 | cc = &active_state->send_context; | |
342 | else | |
343 | cc = &active_state->receive_context; | |
344 | ||
345 | return (cipher_get_keycontext(cc, dat)); | |
346 | } | |
347 | ||
348 | void | |
349 | packet_set_keycontext(int mode, u_char *dat) | |
350 | { | |
351 | CipherContext *cc; | |
352 | ||
353 | if (mode == MODE_OUT) | |
354 | cc = &active_state->send_context; | |
355 | else | |
356 | cc = &active_state->receive_context; | |
357 | ||
358 | cipher_set_keycontext(cc, dat); | |
359 | } | |
360 | ||
361 | int | |
362 | packet_get_keyiv_len(int mode) | |
363 | { | |
364 | CipherContext *cc; | |
365 | ||
366 | if (mode == MODE_OUT) | |
367 | cc = &active_state->send_context; | |
368 | else | |
369 | cc = &active_state->receive_context; | |
370 | ||
371 | return (cipher_get_keyiv_len(cc)); | |
372 | } | |
373 | ||
374 | void | |
375 | packet_set_iv(int mode, u_char *dat) | |
376 | { | |
377 | CipherContext *cc; | |
378 | ||
379 | if (mode == MODE_OUT) | |
380 | cc = &active_state->send_context; | |
381 | else | |
382 | cc = &active_state->receive_context; | |
383 | ||
384 | cipher_set_keyiv(cc, dat); | |
385 | } | |
386 | ||
387 | int | |
388 | packet_get_ssh1_cipher(void) | |
389 | { | |
390 | return (cipher_get_number(active_state->receive_context.cipher)); | |
391 | } | |
392 | ||
393 | void | |
394 | packet_get_state(int mode, u_int32_t *seqnr, u_int64_t *blocks, u_int32_t *packets, | |
395 | u_int64_t *bytes) | |
396 | { | |
397 | struct packet_state *state; | |
398 | ||
399 | state = (mode == MODE_IN) ? | |
400 | &active_state->p_read : &active_state->p_send; | |
401 | if (seqnr) | |
402 | *seqnr = state->seqnr; | |
403 | if (blocks) | |
404 | *blocks = state->blocks; | |
405 | if (packets) | |
406 | *packets = state->packets; | |
407 | if (bytes) | |
408 | *bytes = state->bytes; | |
409 | } | |
410 | ||
411 | void | |
412 | packet_set_state(int mode, u_int32_t seqnr, u_int64_t blocks, u_int32_t packets, | |
413 | u_int64_t bytes) | |
414 | { | |
415 | struct packet_state *state; | |
416 | ||
417 | state = (mode == MODE_IN) ? | |
418 | &active_state->p_read : &active_state->p_send; | |
419 | state->seqnr = seqnr; | |
420 | state->blocks = blocks; | |
421 | state->packets = packets; | |
422 | state->bytes = bytes; | |
423 | } | |
424 | ||
425 | /* returns 1 if connection is via ipv4 */ | |
426 | ||
427 | int | |
428 | packet_connection_is_ipv4(void) | |
429 | { | |
430 | struct sockaddr_storage to; | |
431 | socklen_t tolen = sizeof(to); | |
432 | ||
433 | memset(&to, 0, sizeof(to)); | |
434 | if (getsockname(active_state->connection_out, (struct sockaddr *)&to, | |
435 | &tolen) < 0) | |
436 | return 0; | |
437 | if (to.ss_family == AF_INET) | |
438 | return 1; | |
439 | #ifdef IPV4_IN_IPV6 | |
440 | if (to.ss_family == AF_INET6 && | |
441 | IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)&to)->sin6_addr)) | |
442 | return 1; | |
443 | #endif | |
444 | return 0; | |
445 | } | |
446 | ||
447 | /* Sets the connection into non-blocking mode. */ | |
448 | ||
449 | void | |
450 | packet_set_nonblocking(void) | |
451 | { | |
452 | /* Set the socket into non-blocking mode. */ | |
453 | set_nonblock(active_state->connection_in); | |
454 | ||
455 | if (active_state->connection_out != active_state->connection_in) | |
456 | set_nonblock(active_state->connection_out); | |
457 | } | |
458 | ||
459 | /* Returns the socket used for reading. */ | |
460 | ||
461 | int | |
462 | packet_get_connection_in(void) | |
463 | { | |
464 | return active_state->connection_in; | |
465 | } | |
466 | ||
467 | /* Returns the descriptor used for writing. */ | |
468 | ||
469 | int | |
470 | packet_get_connection_out(void) | |
471 | { | |
472 | return active_state->connection_out; | |
473 | } | |
474 | ||
475 | /* Closes the connection and clears and frees internal data structures. */ | |
476 | ||
477 | void | |
478 | packet_close(void) | |
479 | { | |
480 | if (!active_state->initialized) | |
481 | return; | |
482 | active_state->initialized = 0; | |
483 | if (active_state->connection_in == active_state->connection_out) { | |
484 | shutdown(active_state->connection_out, SHUT_RDWR); | |
485 | close(active_state->connection_out); | |
486 | } else { | |
487 | close(active_state->connection_in); | |
488 | close(active_state->connection_out); | |
489 | } | |
490 | buffer_free(&active_state->input); | |
491 | buffer_free(&active_state->output); | |
492 | buffer_free(&active_state->outgoing_packet); | |
493 | buffer_free(&active_state->incoming_packet); | |
494 | if (active_state->compression_buffer_ready) { | |
495 | buffer_free(&active_state->compression_buffer); | |
496 | buffer_compress_uninit(); | |
497 | } | |
498 | cipher_cleanup(&active_state->send_context); | |
499 | cipher_cleanup(&active_state->receive_context); | |
500 | } | |
501 | ||
502 | /* Sets remote side protocol flags. */ | |
503 | ||
504 | void | |
505 | packet_set_protocol_flags(u_int protocol_flags) | |
506 | { | |
507 | active_state->remote_protocol_flags = protocol_flags; | |
508 | } | |
509 | ||
510 | /* Returns the remote protocol flags set earlier by the above function. */ | |
511 | ||
512 | u_int | |
513 | packet_get_protocol_flags(void) | |
514 | { | |
515 | return active_state->remote_protocol_flags; | |
516 | } | |
517 | ||
518 | /* | |
519 | * Starts packet compression from the next packet on in both directions. | |
520 | * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip. | |
521 | */ | |
522 | ||
523 | static void | |
524 | packet_init_compression(void) | |
525 | { | |
526 | if (active_state->compression_buffer_ready == 1) | |
527 | return; | |
528 | active_state->compression_buffer_ready = 1; | |
529 | buffer_init(&active_state->compression_buffer); | |
530 | } | |
531 | ||
532 | void | |
533 | packet_start_compression(int level) | |
534 | { | |
535 | if (active_state->packet_compression && !compat20) | |
536 | fatal("Compression already enabled."); | |
537 | active_state->packet_compression = 1; | |
538 | packet_init_compression(); | |
539 | buffer_compress_init_send(level); | |
540 | buffer_compress_init_recv(); | |
541 | } | |
542 | ||
543 | /* | |
544 | * Causes any further packets to be encrypted using the given key. The same | |
545 | * key is used for both sending and reception. However, both directions are | |
546 | * encrypted independently of each other. | |
547 | */ | |
548 | ||
549 | void | |
550 | packet_set_encryption_key(const u_char *key, u_int keylen, | |
551 | int number) | |
552 | { | |
553 | Cipher *cipher = cipher_by_number(number); | |
554 | ||
555 | if (cipher == NULL) | |
556 | fatal("packet_set_encryption_key: unknown cipher number %d", number); | |
557 | if (keylen < 20) | |
558 | fatal("packet_set_encryption_key: keylen too small: %d", keylen); | |
559 | if (keylen > SSH_SESSION_KEY_LENGTH) | |
560 | fatal("packet_set_encryption_key: keylen too big: %d", keylen); | |
561 | memcpy(active_state->ssh1_key, key, keylen); | |
562 | active_state->ssh1_keylen = keylen; | |
563 | cipher_init(&active_state->send_context, cipher, key, keylen, NULL, | |
564 | 0, CIPHER_ENCRYPT); | |
565 | cipher_init(&active_state->receive_context, cipher, key, keylen, NULL, | |
566 | 0, CIPHER_DECRYPT); | |
567 | } | |
568 | ||
569 | u_int | |
570 | packet_get_encryption_key(u_char *key) | |
571 | { | |
572 | if (key == NULL) | |
573 | return (active_state->ssh1_keylen); | |
574 | memcpy(key, active_state->ssh1_key, active_state->ssh1_keylen); | |
575 | return (active_state->ssh1_keylen); | |
576 | } | |
577 | ||
578 | /* Start constructing a packet to send. */ | |
579 | void | |
580 | packet_start(u_char type) | |
581 | { | |
582 | u_char buf[9]; | |
583 | int len; | |
584 | ||
585 | DBG(debug("packet_start[%d]", type)); | |
586 | len = compat20 ? 6 : 9; | |
587 | memset(buf, 0, len - 1); | |
588 | buf[len - 1] = type; | |
589 | buffer_clear(&active_state->outgoing_packet); | |
590 | buffer_append(&active_state->outgoing_packet, buf, len); | |
591 | } | |
592 | ||
593 | /* Append payload. */ | |
594 | void | |
595 | packet_put_char(int value) | |
596 | { | |
597 | char ch = value; | |
598 | ||
599 | buffer_append(&active_state->outgoing_packet, &ch, 1); | |
600 | } | |
601 | ||
602 | void | |
603 | packet_put_int(u_int value) | |
604 | { | |
605 | buffer_put_int(&active_state->outgoing_packet, value); | |
606 | } | |
607 | ||
608 | void | |
609 | packet_put_int64(u_int64_t value) | |
610 | { | |
611 | buffer_put_int64(&active_state->outgoing_packet, value); | |
612 | } | |
613 | ||
614 | void | |
615 | packet_put_string(const void *buf, u_int len) | |
616 | { | |
617 | buffer_put_string(&active_state->outgoing_packet, buf, len); | |
618 | } | |
619 | ||
620 | void | |
621 | packet_put_cstring(const char *str) | |
622 | { | |
623 | buffer_put_cstring(&active_state->outgoing_packet, str); | |
624 | } | |
625 | ||
626 | void | |
627 | packet_put_raw(const void *buf, u_int len) | |
628 | { | |
629 | buffer_append(&active_state->outgoing_packet, buf, len); | |
630 | } | |
631 | ||
632 | void | |
633 | packet_put_bignum(BIGNUM * value) | |
634 | { | |
635 | buffer_put_bignum(&active_state->outgoing_packet, value); | |
636 | } | |
637 | ||
638 | void | |
639 | packet_put_bignum2(BIGNUM * value) | |
640 | { | |
641 | buffer_put_bignum2(&active_state->outgoing_packet, value); | |
642 | } | |
643 | ||
644 | /* | |
645 | * Finalizes and sends the packet. If the encryption key has been set, | |
646 | * encrypts the packet before sending. | |
647 | */ | |
648 | ||
649 | static void | |
650 | packet_send1(void) | |
651 | { | |
652 | u_char buf[8], *cp; | |
653 | int i, padding, len; | |
654 | u_int checksum; | |
655 | u_int32_t rnd = 0; | |
656 | ||
657 | /* | |
658 | * If using packet compression, compress the payload of the outgoing | |
659 | * packet. | |
660 | */ | |
661 | if (active_state->packet_compression) { | |
662 | buffer_clear(&active_state->compression_buffer); | |
663 | /* Skip padding. */ | |
664 | buffer_consume(&active_state->outgoing_packet, 8); | |
665 | /* padding */ | |
666 | buffer_append(&active_state->compression_buffer, | |
667 | "\0\0\0\0\0\0\0\0", 8); | |
668 | buffer_compress(&active_state->outgoing_packet, | |
669 | &active_state->compression_buffer); | |
670 | buffer_clear(&active_state->outgoing_packet); | |
671 | buffer_append(&active_state->outgoing_packet, | |
672 | buffer_ptr(&active_state->compression_buffer), | |
673 | buffer_len(&active_state->compression_buffer)); | |
674 | } | |
675 | /* Compute packet length without padding (add checksum, remove padding). */ | |
676 | len = buffer_len(&active_state->outgoing_packet) + 4 - 8; | |
677 | ||
678 | /* Insert padding. Initialized to zero in packet_start1() */ | |
679 | padding = 8 - len % 8; | |
680 | if (!active_state->send_context.plaintext) { | |
681 | cp = buffer_ptr(&active_state->outgoing_packet); | |
682 | for (i = 0; i < padding; i++) { | |
683 | if (i % 4 == 0) | |
684 | rnd = arc4random(); | |
685 | cp[7 - i] = rnd & 0xff; | |
686 | rnd >>= 8; | |
687 | } | |
688 | } | |
689 | buffer_consume(&active_state->outgoing_packet, 8 - padding); | |
690 | ||
691 | /* Add check bytes. */ | |
692 | checksum = ssh_crc32(buffer_ptr(&active_state->outgoing_packet), | |
693 | buffer_len(&active_state->outgoing_packet)); | |
694 | put_u32(buf, checksum); | |
695 | buffer_append(&active_state->outgoing_packet, buf, 4); | |
696 | ||
697 | #ifdef PACKET_DEBUG | |
698 | fprintf(stderr, "packet_send plain: "); | |
699 | buffer_dump(&active_state->outgoing_packet); | |
700 | #endif | |
701 | ||
702 | /* Append to output. */ | |
703 | put_u32(buf, len); | |
704 | buffer_append(&active_state->output, buf, 4); | |
705 | cp = buffer_append_space(&active_state->output, | |
706 | buffer_len(&active_state->outgoing_packet)); | |
707 | cipher_crypt(&active_state->send_context, cp, | |
708 | buffer_ptr(&active_state->outgoing_packet), | |
709 | buffer_len(&active_state->outgoing_packet)); | |
710 | ||
711 | #ifdef PACKET_DEBUG | |
712 | fprintf(stderr, "encrypted: "); | |
713 | buffer_dump(&active_state->output); | |
714 | #endif | |
715 | active_state->p_send.packets++; | |
716 | active_state->p_send.bytes += len + | |
717 | buffer_len(&active_state->outgoing_packet); | |
718 | buffer_clear(&active_state->outgoing_packet); | |
719 | ||
720 | /* | |
721 | * Note that the packet is now only buffered in output. It won't be | |
722 | * actually sent until packet_write_wait or packet_write_poll is | |
723 | * called. | |
724 | */ | |
725 | } | |
726 | ||
727 | void | |
728 | set_newkeys(int mode) | |
729 | { | |
730 | Enc *enc; | |
731 | Mac *mac; | |
732 | Comp *comp; | |
733 | CipherContext *cc; | |
734 | u_int64_t *max_blocks; | |
735 | int crypt_type; | |
736 | ||
737 | debug2("set_newkeys: mode %d", mode); | |
738 | ||
739 | if (mode == MODE_OUT) { | |
740 | cc = &active_state->send_context; | |
741 | crypt_type = CIPHER_ENCRYPT; | |
742 | active_state->p_send.packets = active_state->p_send.blocks = 0; | |
743 | max_blocks = &active_state->max_blocks_out; | |
744 | } else { | |
745 | cc = &active_state->receive_context; | |
746 | crypt_type = CIPHER_DECRYPT; | |
747 | active_state->p_read.packets = active_state->p_read.blocks = 0; | |
748 | max_blocks = &active_state->max_blocks_in; | |
749 | } | |
750 | if (active_state->newkeys[mode] != NULL) { | |
751 | debug("set_newkeys: rekeying"); | |
752 | cipher_cleanup(cc); | |
753 | enc = &active_state->newkeys[mode]->enc; | |
754 | mac = &active_state->newkeys[mode]->mac; | |
755 | comp = &active_state->newkeys[mode]->comp; | |
756 | mac_clear(mac); | |
757 | xfree(enc->name); | |
758 | xfree(enc->iv); | |
759 | xfree(enc->key); | |
760 | xfree(mac->name); | |
761 | xfree(mac->key); | |
762 | xfree(comp->name); | |
763 | xfree(active_state->newkeys[mode]); | |
764 | } | |
765 | active_state->newkeys[mode] = kex_get_newkeys(mode); | |
766 | if (active_state->newkeys[mode] == NULL) | |
767 | fatal("newkeys: no keys for mode %d", mode); | |
768 | enc = &active_state->newkeys[mode]->enc; | |
769 | mac = &active_state->newkeys[mode]->mac; | |
770 | comp = &active_state->newkeys[mode]->comp; | |
771 | if (mac_init(mac) == 0) | |
772 | mac->enabled = 1; | |
773 | DBG(debug("cipher_init_context: %d", mode)); | |
774 | cipher_init(cc, enc->cipher, enc->key, enc->key_len, | |
775 | enc->iv, enc->block_size, crypt_type); | |
776 | /* Deleting the keys does not gain extra security */ | |
777 | /* memset(enc->iv, 0, enc->block_size); | |
778 | memset(enc->key, 0, enc->key_len); | |
779 | memset(mac->key, 0, mac->key_len); */ | |
780 | if ((comp->type == COMP_ZLIB || | |
781 | (comp->type == COMP_DELAYED && | |
782 | active_state->after_authentication)) && comp->enabled == 0) { | |
783 | packet_init_compression(); | |
784 | if (mode == MODE_OUT) | |
785 | buffer_compress_init_send(6); | |
786 | else | |
787 | buffer_compress_init_recv(); | |
788 | comp->enabled = 1; | |
789 | } | |
790 | /* | |
791 | * The 2^(blocksize*2) limit is too expensive for 3DES, | |
792 | * blowfish, etc, so enforce a 1GB limit for small blocksizes. | |
793 | */ | |
794 | if (enc->block_size >= 16) | |
795 | *max_blocks = (u_int64_t)1 << (enc->block_size*2); | |
796 | else | |
797 | *max_blocks = ((u_int64_t)1 << 30) / enc->block_size; | |
798 | if (active_state->rekey_limit) | |
799 | *max_blocks = MIN(*max_blocks, | |
800 | active_state->rekey_limit / enc->block_size); | |
801 | } | |
802 | ||
803 | /* | |
804 | * Delayed compression for SSH2 is enabled after authentication: | |
805 | * This happens on the server side after a SSH2_MSG_USERAUTH_SUCCESS is sent, | |
806 | * and on the client side after a SSH2_MSG_USERAUTH_SUCCESS is received. | |
807 | */ | |
808 | static void | |
809 | packet_enable_delayed_compress(void) | |
810 | { | |
811 | Comp *comp = NULL; | |
812 | int mode; | |
813 | ||
814 | /* | |
815 | * Remember that we are past the authentication step, so rekeying | |
816 | * with COMP_DELAYED will turn on compression immediately. | |
817 | */ | |
818 | active_state->after_authentication = 1; | |
819 | for (mode = 0; mode < MODE_MAX; mode++) { | |
820 | /* protocol error: USERAUTH_SUCCESS received before NEWKEYS */ | |
821 | if (active_state->newkeys[mode] == NULL) | |
822 | continue; | |
823 | comp = &active_state->newkeys[mode]->comp; | |
824 | if (comp && !comp->enabled && comp->type == COMP_DELAYED) { | |
825 | packet_init_compression(); | |
826 | if (mode == MODE_OUT) | |
827 | buffer_compress_init_send(6); | |
828 | else | |
829 | buffer_compress_init_recv(); | |
830 | comp->enabled = 1; | |
831 | } | |
832 | } | |
833 | } | |
834 | ||
835 | /* | |
836 | * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue) | |
837 | */ | |
838 | static void | |
839 | packet_send2_wrapped(void) | |
840 | { | |
841 | u_char type, *cp, *macbuf = NULL; | |
842 | u_char padlen, pad; | |
843 | u_int packet_length = 0; | |
844 | u_int i, len; | |
845 | u_int32_t rnd = 0; | |
846 | Enc *enc = NULL; | |
847 | Mac *mac = NULL; | |
848 | Comp *comp = NULL; | |
849 | int block_size; | |
850 | ||
851 | if (active_state->newkeys[MODE_OUT] != NULL) { | |
852 | enc = &active_state->newkeys[MODE_OUT]->enc; | |
853 | mac = &active_state->newkeys[MODE_OUT]->mac; | |
854 | comp = &active_state->newkeys[MODE_OUT]->comp; | |
855 | } | |
856 | block_size = enc ? enc->block_size : 8; | |
857 | ||
858 | cp = buffer_ptr(&active_state->outgoing_packet); | |
859 | type = cp[5]; | |
860 | ||
861 | #ifdef PACKET_DEBUG | |
862 | fprintf(stderr, "plain: "); | |
863 | buffer_dump(&active_state->outgoing_packet); | |
864 | #endif | |
865 | ||
866 | if (comp && comp->enabled) { | |
867 | len = buffer_len(&active_state->outgoing_packet); | |
868 | /* skip header, compress only payload */ | |
869 | buffer_consume(&active_state->outgoing_packet, 5); | |
870 | buffer_clear(&active_state->compression_buffer); | |
871 | buffer_compress(&active_state->outgoing_packet, | |
872 | &active_state->compression_buffer); | |
873 | buffer_clear(&active_state->outgoing_packet); | |
874 | buffer_append(&active_state->outgoing_packet, "\0\0\0\0\0", 5); | |
875 | buffer_append(&active_state->outgoing_packet, | |
876 | buffer_ptr(&active_state->compression_buffer), | |
877 | buffer_len(&active_state->compression_buffer)); | |
878 | DBG(debug("compression: raw %d compressed %d", len, | |
879 | buffer_len(&active_state->outgoing_packet))); | |
880 | } | |
881 | ||
882 | /* sizeof (packet_len + pad_len + payload) */ | |
883 | len = buffer_len(&active_state->outgoing_packet); | |
884 | ||
885 | /* | |
886 | * calc size of padding, alloc space, get random data, | |
887 | * minimum padding is 4 bytes | |
888 | */ | |
889 | padlen = block_size - (len % block_size); | |
890 | if (padlen < 4) | |
891 | padlen += block_size; | |
892 | if (active_state->extra_pad) { | |
893 | /* will wrap if extra_pad+padlen > 255 */ | |
894 | active_state->extra_pad = | |
895 | roundup(active_state->extra_pad, block_size); | |
896 | pad = active_state->extra_pad - | |
897 | ((len + padlen) % active_state->extra_pad); | |
898 | debug3("packet_send2: adding %d (len %d padlen %d extra_pad %d)", | |
899 | pad, len, padlen, active_state->extra_pad); | |
900 | padlen += pad; | |
901 | active_state->extra_pad = 0; | |
902 | } | |
903 | cp = buffer_append_space(&active_state->outgoing_packet, padlen); | |
904 | if (enc && !active_state->send_context.plaintext) { | |
905 | /* random padding */ | |
906 | for (i = 0; i < padlen; i++) { | |
907 | if (i % 4 == 0) | |
908 | rnd = arc4random(); | |
909 | cp[i] = rnd & 0xff; | |
910 | rnd >>= 8; | |
911 | } | |
912 | } else { | |
913 | /* clear padding */ | |
914 | memset(cp, 0, padlen); | |
915 | } | |
916 | /* packet_length includes payload, padding and padding length field */ | |
917 | packet_length = buffer_len(&active_state->outgoing_packet) - 4; | |
918 | cp = buffer_ptr(&active_state->outgoing_packet); | |
919 | put_u32(cp, packet_length); | |
920 | cp[4] = padlen; | |
921 | DBG(debug("send: len %d (includes padlen %d)", packet_length+4, padlen)); | |
922 | ||
923 | /* compute MAC over seqnr and packet(length fields, payload, padding) */ | |
924 | if (mac && mac->enabled) { | |
925 | macbuf = mac_compute(mac, active_state->p_send.seqnr, | |
926 | buffer_ptr(&active_state->outgoing_packet), | |
927 | buffer_len(&active_state->outgoing_packet)); | |
928 | DBG(debug("done calc MAC out #%d", active_state->p_send.seqnr)); | |
929 | } | |
930 | /* encrypt packet and append to output buffer. */ | |
931 | cp = buffer_append_space(&active_state->output, | |
932 | buffer_len(&active_state->outgoing_packet)); | |
933 | cipher_crypt(&active_state->send_context, cp, | |
934 | buffer_ptr(&active_state->outgoing_packet), | |
935 | buffer_len(&active_state->outgoing_packet)); | |
936 | /* append unencrypted MAC */ | |
937 | if (mac && mac->enabled) | |
938 | buffer_append(&active_state->output, macbuf, mac->mac_len); | |
939 | #ifdef PACKET_DEBUG | |
940 | fprintf(stderr, "encrypted: "); | |
941 | buffer_dump(&active_state->output); | |
942 | #endif | |
943 | /* increment sequence number for outgoing packets */ | |
944 | if (++active_state->p_send.seqnr == 0) | |
945 | logit("outgoing seqnr wraps around"); | |
946 | if (++active_state->p_send.packets == 0) | |
947 | if (!(datafellows & SSH_BUG_NOREKEY)) | |
948 | fatal("XXX too many packets with same key"); | |
949 | active_state->p_send.blocks += (packet_length + 4) / block_size; | |
950 | active_state->p_send.bytes += packet_length + 4; | |
951 | buffer_clear(&active_state->outgoing_packet); | |
952 | ||
953 | if (type == SSH2_MSG_NEWKEYS) | |
954 | set_newkeys(MODE_OUT); | |
955 | else if (type == SSH2_MSG_USERAUTH_SUCCESS && active_state->server_side) | |
956 | packet_enable_delayed_compress(); | |
957 | } | |
958 | ||
959 | static void | |
960 | packet_send2(void) | |
961 | { | |
962 | struct packet *p; | |
963 | u_char type, *cp; | |
964 | ||
965 | cp = buffer_ptr(&active_state->outgoing_packet); | |
966 | type = cp[5]; | |
967 | ||
968 | /* during rekeying we can only send key exchange messages */ | |
969 | if (active_state->rekeying) { | |
970 | if (!((type >= SSH2_MSG_TRANSPORT_MIN) && | |
971 | (type <= SSH2_MSG_TRANSPORT_MAX))) { | |
972 | debug("enqueue packet: %u", type); | |
973 | p = xmalloc(sizeof(*p)); | |
974 | p->type = type; | |
975 | memcpy(&p->payload, &active_state->outgoing_packet, | |
976 | sizeof(Buffer)); | |
977 | buffer_init(&active_state->outgoing_packet); | |
978 | TAILQ_INSERT_TAIL(&active_state->outgoing, p, next); | |
979 | return; | |
980 | } | |
981 | } | |
982 | ||
983 | /* rekeying starts with sending KEXINIT */ | |
984 | if (type == SSH2_MSG_KEXINIT) | |
985 | active_state->rekeying = 1; | |
986 | ||
987 | packet_send2_wrapped(); | |
988 | ||
989 | /* after a NEWKEYS message we can send the complete queue */ | |
990 | if (type == SSH2_MSG_NEWKEYS) { | |
991 | active_state->rekeying = 0; | |
992 | while ((p = TAILQ_FIRST(&active_state->outgoing))) { | |
993 | type = p->type; | |
994 | debug("dequeue packet: %u", type); | |
995 | buffer_free(&active_state->outgoing_packet); | |
996 | memcpy(&active_state->outgoing_packet, &p->payload, | |
997 | sizeof(Buffer)); | |
998 | TAILQ_REMOVE(&active_state->outgoing, p, next); | |
999 | xfree(p); | |
1000 | packet_send2_wrapped(); | |
1001 | } | |
1002 | } | |
1003 | } | |
1004 | ||
1005 | void | |
1006 | packet_send(void) | |
1007 | { | |
1008 | if (compat20) | |
1009 | packet_send2(); | |
1010 | else | |
1011 | packet_send1(); | |
1012 | DBG(debug("packet_send done")); | |
1013 | } | |
1014 | ||
1015 | /* | |
1016 | * Waits until a packet has been received, and returns its type. Note that | |
1017 | * no other data is processed until this returns, so this function should not | |
1018 | * be used during the interactive session. | |
1019 | */ | |
1020 | ||
1021 | int | |
1022 | packet_read_seqnr(u_int32_t *seqnr_p) | |
1023 | { | |
1024 | int type, len, ret, ms_remain, cont; | |
1025 | fd_set *setp; | |
1026 | char buf[8192]; | |
1027 | struct timeval timeout, start, *timeoutp = NULL; | |
1028 | ||
1029 | DBG(debug("packet_read()")); | |
1030 | ||
1031 | setp = (fd_set *)xcalloc(howmany(active_state->connection_in + 1, | |
1032 | NFDBITS), sizeof(fd_mask)); | |
1033 | ||
1034 | /* Since we are blocking, ensure that all written packets have been sent. */ | |
1035 | packet_write_wait(); | |
1036 | ||
1037 | /* Stay in the loop until we have received a complete packet. */ | |
1038 | for (;;) { | |
1039 | /* Try to read a packet from the buffer. */ | |
1040 | type = packet_read_poll_seqnr(seqnr_p); | |
1041 | if (!compat20 && ( | |
1042 | type == SSH_SMSG_SUCCESS | |
1043 | || type == SSH_SMSG_FAILURE | |
1044 | || type == SSH_CMSG_EOF | |
1045 | || type == SSH_CMSG_EXIT_CONFIRMATION)) | |
1046 | packet_check_eom(); | |
1047 | /* If we got a packet, return it. */ | |
1048 | if (type != SSH_MSG_NONE) { | |
1049 | xfree(setp); | |
1050 | return type; | |
1051 | } | |
1052 | /* | |
1053 | * Otherwise, wait for some data to arrive, add it to the | |
1054 | * buffer, and try again. | |
1055 | */ | |
1056 | memset(setp, 0, howmany(active_state->connection_in + 1, | |
1057 | NFDBITS) * sizeof(fd_mask)); | |
1058 | FD_SET(active_state->connection_in, setp); | |
1059 | ||
1060 | if (active_state->packet_timeout_ms > 0) { | |
1061 | ms_remain = active_state->packet_timeout_ms; | |
1062 | timeoutp = &timeout; | |
1063 | } | |
1064 | /* Wait for some data to arrive. */ | |
1065 | for (;;) { | |
1066 | if (active_state->packet_timeout_ms != -1) { | |
1067 | ms_to_timeval(&timeout, ms_remain); | |
1068 | gettimeofday(&start, NULL); | |
1069 | } | |
1070 | if ((ret = select(active_state->connection_in + 1, setp, | |
1071 | NULL, NULL, timeoutp)) >= 0) | |
1072 | break; | |
1073 | if (errno != EAGAIN && errno != EINTR && | |
1074 | errno != EWOULDBLOCK) | |
1075 | break; | |
1076 | if (active_state->packet_timeout_ms == -1) | |
1077 | continue; | |
1078 | ms_subtract_diff(&start, &ms_remain); | |
1079 | if (ms_remain <= 0) { | |
1080 | ret = 0; | |
1081 | break; | |
1082 | } | |
1083 | } | |
1084 | if (ret == 0) { | |
1085 | logit("Connection to %.200s timed out while " | |
1086 | "waiting to read", get_remote_ipaddr()); | |
1087 | cleanup_exit(255); | |
1088 | } | |
1089 | /* Read data from the socket. */ | |
1090 | do { | |
1091 | cont = 0; | |
1092 | len = roaming_read(active_state->connection_in, buf, | |
1093 | sizeof(buf), &cont); | |
1094 | } while (len == 0 && cont); | |
1095 | if (len == 0) { | |
1096 | logit("Connection closed by %.200s", get_remote_ipaddr()); | |
1097 | cleanup_exit(255); | |
1098 | } | |
1099 | if (len < 0) | |
1100 | fatal("Read from socket failed: %.100s", strerror(errno)); | |
1101 | /* Append it to the buffer. */ | |
1102 | packet_process_incoming(buf, len); | |
1103 | } | |
1104 | /* NOTREACHED */ | |
1105 | } | |
1106 | ||
1107 | int | |
1108 | packet_read(void) | |
1109 | { | |
1110 | return packet_read_seqnr(NULL); | |
1111 | } | |
1112 | ||
1113 | /* | |
1114 | * Waits until a packet has been received, verifies that its type matches | |
1115 | * that given, and gives a fatal error and exits if there is a mismatch. | |
1116 | */ | |
1117 | ||
1118 | void | |
1119 | packet_read_expect(int expected_type) | |
1120 | { | |
1121 | int type; | |
1122 | ||
1123 | type = packet_read(); | |
1124 | if (type != expected_type) | |
1125 | packet_disconnect("Protocol error: expected packet type %d, got %d", | |
1126 | expected_type, type); | |
1127 | } | |
1128 | ||
1129 | /* Checks if a full packet is available in the data received so far via | |
1130 | * packet_process_incoming. If so, reads the packet; otherwise returns | |
1131 | * SSH_MSG_NONE. This does not wait for data from the connection. | |
1132 | * | |
1133 | * SSH_MSG_DISCONNECT is handled specially here. Also, | |
1134 | * SSH_MSG_IGNORE messages are skipped by this function and are never returned | |
1135 | * to higher levels. | |
1136 | */ | |
1137 | ||
1138 | static int | |
1139 | packet_read_poll1(void) | |
1140 | { | |
1141 | u_int len, padded_len; | |
1142 | u_char *cp, type; | |
1143 | u_int checksum, stored_checksum; | |
1144 | ||
1145 | /* Check if input size is less than minimum packet size. */ | |
1146 | if (buffer_len(&active_state->input) < 4 + 8) | |
1147 | return SSH_MSG_NONE; | |
1148 | /* Get length of incoming packet. */ | |
1149 | cp = buffer_ptr(&active_state->input); | |
1150 | len = get_u32(cp); | |
1151 | if (len < 1 + 2 + 2 || len > 256 * 1024) | |
1152 | packet_disconnect("Bad packet length %u.", len); | |
1153 | padded_len = (len + 8) & ~7; | |
1154 | ||
1155 | /* Check if the packet has been entirely received. */ | |
1156 | if (buffer_len(&active_state->input) < 4 + padded_len) | |
1157 | return SSH_MSG_NONE; | |
1158 | ||
1159 | /* The entire packet is in buffer. */ | |
1160 | ||
1161 | /* Consume packet length. */ | |
1162 | buffer_consume(&active_state->input, 4); | |
1163 | ||
1164 | /* | |
1165 | * Cryptographic attack detector for ssh | |
1166 | * (C)1998 CORE-SDI, Buenos Aires Argentina | |
1167 | * Ariel Futoransky(futo@core-sdi.com) | |
1168 | */ | |
1169 | if (!active_state->receive_context.plaintext) { | |
1170 | switch (detect_attack(buffer_ptr(&active_state->input), | |
1171 | padded_len)) { | |
1172 | case DEATTACK_DETECTED: | |
1173 | packet_disconnect("crc32 compensation attack: " | |
1174 | "network attack detected"); | |
1175 | case DEATTACK_DOS_DETECTED: | |
1176 | packet_disconnect("deattack denial of " | |
1177 | "service detected"); | |
1178 | } | |
1179 | } | |
1180 | ||
1181 | /* Decrypt data to incoming_packet. */ | |
1182 | buffer_clear(&active_state->incoming_packet); | |
1183 | cp = buffer_append_space(&active_state->incoming_packet, padded_len); | |
1184 | cipher_crypt(&active_state->receive_context, cp, | |
1185 | buffer_ptr(&active_state->input), padded_len); | |
1186 | ||
1187 | buffer_consume(&active_state->input, padded_len); | |
1188 | ||
1189 | #ifdef PACKET_DEBUG | |
1190 | fprintf(stderr, "read_poll plain: "); | |
1191 | buffer_dump(&active_state->incoming_packet); | |
1192 | #endif | |
1193 | ||
1194 | /* Compute packet checksum. */ | |
1195 | checksum = ssh_crc32(buffer_ptr(&active_state->incoming_packet), | |
1196 | buffer_len(&active_state->incoming_packet) - 4); | |
1197 | ||
1198 | /* Skip padding. */ | |
1199 | buffer_consume(&active_state->incoming_packet, 8 - len % 8); | |
1200 | ||
1201 | /* Test check bytes. */ | |
1202 | if (len != buffer_len(&active_state->incoming_packet)) | |
1203 | packet_disconnect("packet_read_poll1: len %d != buffer_len %d.", | |
1204 | len, buffer_len(&active_state->incoming_packet)); | |
1205 | ||
1206 | cp = (u_char *)buffer_ptr(&active_state->incoming_packet) + len - 4; | |
1207 | stored_checksum = get_u32(cp); | |
1208 | if (checksum != stored_checksum) | |
1209 | packet_disconnect("Corrupted check bytes on input."); | |
1210 | buffer_consume_end(&active_state->incoming_packet, 4); | |
1211 | ||
1212 | if (active_state->packet_compression) { | |
1213 | buffer_clear(&active_state->compression_buffer); | |
1214 | buffer_uncompress(&active_state->incoming_packet, | |
1215 | &active_state->compression_buffer); | |
1216 | buffer_clear(&active_state->incoming_packet); | |
1217 | buffer_append(&active_state->incoming_packet, | |
1218 | buffer_ptr(&active_state->compression_buffer), | |
1219 | buffer_len(&active_state->compression_buffer)); | |
1220 | } | |
1221 | active_state->p_read.packets++; | |
1222 | active_state->p_read.bytes += padded_len + 4; | |
1223 | type = buffer_get_char(&active_state->incoming_packet); | |
1224 | if (type < SSH_MSG_MIN || type > SSH_MSG_MAX) | |
1225 | packet_disconnect("Invalid ssh1 packet type: %d", type); | |
1226 | return type; | |
1227 | } | |
1228 | ||
1229 | static int | |
1230 | packet_read_poll2(u_int32_t *seqnr_p) | |
1231 | { | |
1232 | u_int padlen, need; | |
1233 | u_char *macbuf, *cp, type; | |
1234 | u_int maclen, block_size; | |
1235 | Enc *enc = NULL; | |
1236 | Mac *mac = NULL; | |
1237 | Comp *comp = NULL; | |
1238 | ||
1239 | if (active_state->packet_discard) | |
1240 | return SSH_MSG_NONE; | |
1241 | ||
1242 | if (active_state->newkeys[MODE_IN] != NULL) { | |
1243 | enc = &active_state->newkeys[MODE_IN]->enc; | |
1244 | mac = &active_state->newkeys[MODE_IN]->mac; | |
1245 | comp = &active_state->newkeys[MODE_IN]->comp; | |
1246 | } | |
1247 | maclen = mac && mac->enabled ? mac->mac_len : 0; | |
1248 | block_size = enc ? enc->block_size : 8; | |
1249 | ||
1250 | if (active_state->packlen == 0) { | |
1251 | /* | |
1252 | * check if input size is less than the cipher block size, | |
1253 | * decrypt first block and extract length of incoming packet | |
1254 | */ | |
1255 | if (buffer_len(&active_state->input) < block_size) | |
1256 | return SSH_MSG_NONE; | |
1257 | buffer_clear(&active_state->incoming_packet); | |
1258 | cp = buffer_append_space(&active_state->incoming_packet, | |
1259 | block_size); | |
1260 | cipher_crypt(&active_state->receive_context, cp, | |
1261 | buffer_ptr(&active_state->input), block_size); | |
1262 | cp = buffer_ptr(&active_state->incoming_packet); | |
1263 | active_state->packlen = get_u32(cp); | |
1264 | if (active_state->packlen < 1 + 4 || | |
1265 | active_state->packlen > PACKET_MAX_SIZE) { | |
1266 | #ifdef PACKET_DEBUG | |
1267 | buffer_dump(&active_state->incoming_packet); | |
1268 | #endif | |
1269 | logit("Bad packet length %u.", active_state->packlen); | |
1270 | packet_start_discard(enc, mac, active_state->packlen, | |
1271 | PACKET_MAX_SIZE); | |
1272 | return SSH_MSG_NONE; | |
1273 | } | |
1274 | DBG(debug("input: packet len %u", active_state->packlen+4)); | |
1275 | buffer_consume(&active_state->input, block_size); | |
1276 | } | |
1277 | /* we have a partial packet of block_size bytes */ | |
1278 | need = 4 + active_state->packlen - block_size; | |
1279 | DBG(debug("partial packet %d, need %d, maclen %d", block_size, | |
1280 | need, maclen)); | |
1281 | if (need % block_size != 0) { | |
1282 | logit("padding error: need %d block %d mod %d", | |
1283 | need, block_size, need % block_size); | |
1284 | packet_start_discard(enc, mac, active_state->packlen, | |
1285 | PACKET_MAX_SIZE - block_size); | |
1286 | return SSH_MSG_NONE; | |
1287 | } | |
1288 | /* | |
1289 | * check if the entire packet has been received and | |
1290 | * decrypt into incoming_packet | |
1291 | */ | |
1292 | if (buffer_len(&active_state->input) < need + maclen) | |
1293 | return SSH_MSG_NONE; | |
1294 | #ifdef PACKET_DEBUG | |
1295 | fprintf(stderr, "read_poll enc/full: "); | |
1296 | buffer_dump(&active_state->input); | |
1297 | #endif | |
1298 | cp = buffer_append_space(&active_state->incoming_packet, need); | |
1299 | cipher_crypt(&active_state->receive_context, cp, | |
1300 | buffer_ptr(&active_state->input), need); | |
1301 | buffer_consume(&active_state->input, need); | |
1302 | /* | |
1303 | * compute MAC over seqnr and packet, | |
1304 | * increment sequence number for incoming packet | |
1305 | */ | |
1306 | if (mac && mac->enabled) { | |
1307 | macbuf = mac_compute(mac, active_state->p_read.seqnr, | |
1308 | buffer_ptr(&active_state->incoming_packet), | |
1309 | buffer_len(&active_state->incoming_packet)); | |
1310 | if (memcmp(macbuf, buffer_ptr(&active_state->input), | |
1311 | mac->mac_len) != 0) { | |
1312 | logit("Corrupted MAC on input."); | |
1313 | if (need > PACKET_MAX_SIZE) | |
1314 | fatal("internal error need %d", need); | |
1315 | packet_start_discard(enc, mac, active_state->packlen, | |
1316 | PACKET_MAX_SIZE - need); | |
1317 | return SSH_MSG_NONE; | |
1318 | } | |
1319 | ||
1320 | DBG(debug("MAC #%d ok", active_state->p_read.seqnr)); | |
1321 | buffer_consume(&active_state->input, mac->mac_len); | |
1322 | } | |
1323 | /* XXX now it's safe to use fatal/packet_disconnect */ | |
1324 | if (seqnr_p != NULL) | |
1325 | *seqnr_p = active_state->p_read.seqnr; | |
1326 | if (++active_state->p_read.seqnr == 0) | |
1327 | logit("incoming seqnr wraps around"); | |
1328 | if (++active_state->p_read.packets == 0) | |
1329 | if (!(datafellows & SSH_BUG_NOREKEY)) | |
1330 | fatal("XXX too many packets with same key"); | |
1331 | active_state->p_read.blocks += (active_state->packlen + 4) / block_size; | |
1332 | active_state->p_read.bytes += active_state->packlen + 4; | |
1333 | ||
1334 | /* get padlen */ | |
1335 | cp = buffer_ptr(&active_state->incoming_packet); | |
1336 | padlen = cp[4]; | |
1337 | DBG(debug("input: padlen %d", padlen)); | |
1338 | if (padlen < 4) | |
1339 | packet_disconnect("Corrupted padlen %d on input.", padlen); | |
1340 | ||
1341 | /* skip packet size + padlen, discard padding */ | |
1342 | buffer_consume(&active_state->incoming_packet, 4 + 1); | |
1343 | buffer_consume_end(&active_state->incoming_packet, padlen); | |
1344 | ||
1345 | DBG(debug("input: len before de-compress %d", | |
1346 | buffer_len(&active_state->incoming_packet))); | |
1347 | if (comp && comp->enabled) { | |
1348 | buffer_clear(&active_state->compression_buffer); | |
1349 | buffer_uncompress(&active_state->incoming_packet, | |
1350 | &active_state->compression_buffer); | |
1351 | buffer_clear(&active_state->incoming_packet); | |
1352 | buffer_append(&active_state->incoming_packet, | |
1353 | buffer_ptr(&active_state->compression_buffer), | |
1354 | buffer_len(&active_state->compression_buffer)); | |
1355 | DBG(debug("input: len after de-compress %d", | |
1356 | buffer_len(&active_state->incoming_packet))); | |
1357 | } | |
1358 | /* | |
1359 | * get packet type, implies consume. | |
1360 | * return length of payload (without type field) | |
1361 | */ | |
1362 | type = buffer_get_char(&active_state->incoming_packet); | |
1363 | if (type < SSH2_MSG_MIN || type >= SSH2_MSG_LOCAL_MIN) | |
1364 | packet_disconnect("Invalid ssh2 packet type: %d", type); | |
1365 | if (type == SSH2_MSG_NEWKEYS) | |
1366 | set_newkeys(MODE_IN); | |
1367 | else if (type == SSH2_MSG_USERAUTH_SUCCESS && | |
1368 | !active_state->server_side) | |
1369 | packet_enable_delayed_compress(); | |
1370 | #ifdef PACKET_DEBUG | |
1371 | fprintf(stderr, "read/plain[%d]:\r\n", type); | |
1372 | buffer_dump(&active_state->incoming_packet); | |
1373 | #endif | |
1374 | /* reset for next packet */ | |
1375 | active_state->packlen = 0; | |
1376 | return type; | |
1377 | } | |
1378 | ||
1379 | int | |
1380 | packet_read_poll_seqnr(u_int32_t *seqnr_p) | |
1381 | { | |
1382 | u_int reason, seqnr; | |
1383 | u_char type; | |
1384 | char *msg; | |
1385 | ||
1386 | for (;;) { | |
1387 | if (compat20) { | |
1388 | type = packet_read_poll2(seqnr_p); | |
1389 | if (type) { | |
1390 | active_state->keep_alive_timeouts = 0; | |
1391 | DBG(debug("received packet type %d", type)); | |
1392 | } | |
1393 | switch (type) { | |
1394 | case SSH2_MSG_IGNORE: | |
1395 | debug3("Received SSH2_MSG_IGNORE"); | |
1396 | break; | |
1397 | case SSH2_MSG_DEBUG: | |
1398 | packet_get_char(); | |
1399 | msg = packet_get_string(NULL); | |
1400 | debug("Remote: %.900s", msg); | |
1401 | xfree(msg); | |
1402 | msg = packet_get_string(NULL); | |
1403 | xfree(msg); | |
1404 | break; | |
1405 | case SSH2_MSG_DISCONNECT: | |
1406 | reason = packet_get_int(); | |
1407 | msg = packet_get_string(NULL); | |
1408 | logit("Received disconnect from %s: %u: %.400s", | |
1409 | get_remote_ipaddr(), reason, msg); | |
1410 | xfree(msg); | |
1411 | cleanup_exit(255); | |
1412 | break; | |
1413 | case SSH2_MSG_UNIMPLEMENTED: | |
1414 | seqnr = packet_get_int(); | |
1415 | debug("Received SSH2_MSG_UNIMPLEMENTED for %u", | |
1416 | seqnr); | |
1417 | break; | |
1418 | default: | |
1419 | return type; | |
1420 | } | |
1421 | } else { | |
1422 | type = packet_read_poll1(); | |
1423 | switch (type) { | |
1424 | case SSH_MSG_IGNORE: | |
1425 | break; | |
1426 | case SSH_MSG_DEBUG: | |
1427 | msg = packet_get_string(NULL); | |
1428 | debug("Remote: %.900s", msg); | |
1429 | xfree(msg); | |
1430 | break; | |
1431 | case SSH_MSG_DISCONNECT: | |
1432 | msg = packet_get_string(NULL); | |
1433 | logit("Received disconnect from %s: %.400s", | |
1434 | get_remote_ipaddr(), msg); | |
1435 | cleanup_exit(255); | |
1436 | break; | |
1437 | default: | |
1438 | if (type) | |
1439 | DBG(debug("received packet type %d", type)); | |
1440 | return type; | |
1441 | } | |
1442 | } | |
1443 | } | |
1444 | } | |
1445 | ||
1446 | int | |
1447 | packet_read_poll(void) | |
1448 | { | |
1449 | return packet_read_poll_seqnr(NULL); | |
1450 | } | |
1451 | ||
1452 | /* | |
1453 | * Buffers the given amount of input characters. This is intended to be used | |
1454 | * together with packet_read_poll. | |
1455 | */ | |
1456 | ||
1457 | void | |
1458 | packet_process_incoming(const char *buf, u_int len) | |
1459 | { | |
1460 | if (active_state->packet_discard) { | |
1461 | active_state->keep_alive_timeouts = 0; /* ?? */ | |
1462 | if (len >= active_state->packet_discard) | |
1463 | packet_stop_discard(); | |
1464 | active_state->packet_discard -= len; | |
1465 | return; | |
1466 | } | |
1467 | buffer_append(&active_state->input, buf, len); | |
1468 | } | |
1469 | ||
1470 | /* Returns a character from the packet. */ | |
1471 | ||
1472 | u_int | |
1473 | packet_get_char(void) | |
1474 | { | |
1475 | char ch; | |
1476 | ||
1477 | buffer_get(&active_state->incoming_packet, &ch, 1); | |
1478 | return (u_char) ch; | |
1479 | } | |
1480 | ||
1481 | /* Returns an integer from the packet data. */ | |
1482 | ||
1483 | u_int | |
1484 | packet_get_int(void) | |
1485 | { | |
1486 | return buffer_get_int(&active_state->incoming_packet); | |
1487 | } | |
1488 | ||
1489 | /* Returns an 64 bit integer from the packet data. */ | |
1490 | ||
1491 | u_int64_t | |
1492 | packet_get_int64(void) | |
1493 | { | |
1494 | return buffer_get_int64(&active_state->incoming_packet); | |
1495 | } | |
1496 | ||
1497 | /* | |
1498 | * Returns an arbitrary precision integer from the packet data. The integer | |
1499 | * must have been initialized before this call. | |
1500 | */ | |
1501 | ||
1502 | void | |
1503 | packet_get_bignum(BIGNUM * value) | |
1504 | { | |
1505 | buffer_get_bignum(&active_state->incoming_packet, value); | |
1506 | } | |
1507 | ||
1508 | void | |
1509 | packet_get_bignum2(BIGNUM * value) | |
1510 | { | |
1511 | buffer_get_bignum2(&active_state->incoming_packet, value); | |
1512 | } | |
1513 | ||
1514 | void * | |
1515 | packet_get_raw(u_int *length_ptr) | |
1516 | { | |
1517 | u_int bytes = buffer_len(&active_state->incoming_packet); | |
1518 | ||
1519 | if (length_ptr != NULL) | |
1520 | *length_ptr = bytes; | |
1521 | return buffer_ptr(&active_state->incoming_packet); | |
1522 | } | |
1523 | ||
1524 | int | |
1525 | packet_remaining(void) | |
1526 | { | |
1527 | return buffer_len(&active_state->incoming_packet); | |
1528 | } | |
1529 | ||
1530 | /* | |
1531 | * Returns a string from the packet data. The string is allocated using | |
1532 | * xmalloc; it is the responsibility of the calling program to free it when | |
1533 | * no longer needed. The length_ptr argument may be NULL, or point to an | |
1534 | * integer into which the length of the string is stored. | |
1535 | */ | |
1536 | ||
1537 | void * | |
1538 | packet_get_string(u_int *length_ptr) | |
1539 | { | |
1540 | return buffer_get_string(&active_state->incoming_packet, length_ptr); | |
1541 | } | |
1542 | ||
1543 | void * | |
1544 | packet_get_string_ptr(u_int *length_ptr) | |
1545 | { | |
1546 | return buffer_get_string_ptr(&active_state->incoming_packet, length_ptr); | |
1547 | } | |
1548 | ||
1549 | /* | |
1550 | * Sends a diagnostic message from the server to the client. This message | |
1551 | * can be sent at any time (but not while constructing another message). The | |
1552 | * message is printed immediately, but only if the client is being executed | |
1553 | * in verbose mode. These messages are primarily intended to ease debugging | |
1554 | * authentication problems. The length of the formatted message must not | |
1555 | * exceed 1024 bytes. This will automatically call packet_write_wait. | |
1556 | */ | |
1557 | ||
1558 | void | |
1559 | packet_send_debug(const char *fmt,...) | |
1560 | { | |
1561 | char buf[1024]; | |
1562 | va_list args; | |
1563 | ||
1564 | if (compat20 && (datafellows & SSH_BUG_DEBUG)) | |
1565 | return; | |
1566 | ||
1567 | va_start(args, fmt); | |
1568 | vsnprintf(buf, sizeof(buf), fmt, args); | |
1569 | va_end(args); | |
1570 | ||
1571 | if (compat20) { | |
1572 | packet_start(SSH2_MSG_DEBUG); | |
1573 | packet_put_char(0); /* bool: always display */ | |
1574 | packet_put_cstring(buf); | |
1575 | packet_put_cstring(""); | |
1576 | } else { | |
1577 | packet_start(SSH_MSG_DEBUG); | |
1578 | packet_put_cstring(buf); | |
1579 | } | |
1580 | packet_send(); | |
1581 | packet_write_wait(); | |
1582 | } | |
1583 | ||
1584 | /* | |
1585 | * Logs the error plus constructs and sends a disconnect packet, closes the | |
1586 | * connection, and exits. This function never returns. The error message | |
1587 | * should not contain a newline. The length of the formatted message must | |
1588 | * not exceed 1024 bytes. | |
1589 | */ | |
1590 | ||
1591 | void | |
1592 | packet_disconnect(const char *fmt,...) | |
1593 | { | |
1594 | char buf[1024]; | |
1595 | va_list args; | |
1596 | static int disconnecting = 0; | |
1597 | ||
1598 | if (disconnecting) /* Guard against recursive invocations. */ | |
1599 | fatal("packet_disconnect called recursively."); | |
1600 | disconnecting = 1; | |
1601 | ||
1602 | /* | |
1603 | * Format the message. Note that the caller must make sure the | |
1604 | * message is of limited size. | |
1605 | */ | |
1606 | va_start(args, fmt); | |
1607 | vsnprintf(buf, sizeof(buf), fmt, args); | |
1608 | va_end(args); | |
1609 | ||
1610 | /* Display the error locally */ | |
1611 | logit("Disconnecting: %.100s", buf); | |
1612 | ||
1613 | /* Send the disconnect message to the other side, and wait for it to get sent. */ | |
1614 | if (compat20) { | |
1615 | packet_start(SSH2_MSG_DISCONNECT); | |
1616 | packet_put_int(SSH2_DISCONNECT_PROTOCOL_ERROR); | |
1617 | packet_put_cstring(buf); | |
1618 | packet_put_cstring(""); | |
1619 | } else { | |
1620 | packet_start(SSH_MSG_DISCONNECT); | |
1621 | packet_put_cstring(buf); | |
1622 | } | |
1623 | packet_send(); | |
1624 | packet_write_wait(); | |
1625 | ||
1626 | /* Stop listening for connections. */ | |
1627 | channel_close_all(); | |
1628 | ||
1629 | /* Close the connection. */ | |
1630 | packet_close(); | |
1631 | cleanup_exit(255); | |
1632 | } | |
1633 | ||
1634 | /* Checks if there is any buffered output, and tries to write some of the output. */ | |
1635 | ||
1636 | void | |
1637 | packet_write_poll(void) | |
1638 | { | |
1639 | int len = buffer_len(&active_state->output); | |
1640 | int cont; | |
1641 | ||
1642 | if (len > 0) { | |
1643 | cont = 0; | |
1644 | len = roaming_write(active_state->connection_out, | |
1645 | buffer_ptr(&active_state->output), len, &cont); | |
1646 | if (len == -1) { | |
1647 | if (errno == EINTR || errno == EAGAIN || | |
1648 | errno == EWOULDBLOCK) | |
1649 | return; | |
1650 | fatal("Write failed: %.100s", strerror(errno)); | |
1651 | } | |
1652 | if (len == 0 && !cont) | |
1653 | fatal("Write connection closed"); | |
1654 | buffer_consume(&active_state->output, len); | |
1655 | } | |
1656 | } | |
1657 | ||
1658 | /* | |
1659 | * Calls packet_write_poll repeatedly until all pending output data has been | |
1660 | * written. | |
1661 | */ | |
1662 | ||
1663 | void | |
1664 | packet_write_wait(void) | |
1665 | { | |
1666 | fd_set *setp; | |
1667 | int ret, ms_remain; | |
1668 | struct timeval start, timeout, *timeoutp = NULL; | |
1669 | ||
1670 | setp = (fd_set *)xcalloc(howmany(active_state->connection_out + 1, | |
1671 | NFDBITS), sizeof(fd_mask)); | |
1672 | packet_write_poll(); | |
1673 | while (packet_have_data_to_write()) { | |
1674 | memset(setp, 0, howmany(active_state->connection_out + 1, | |
1675 | NFDBITS) * sizeof(fd_mask)); | |
1676 | FD_SET(active_state->connection_out, setp); | |
1677 | ||
1678 | if (active_state->packet_timeout_ms > 0) { | |
1679 | ms_remain = active_state->packet_timeout_ms; | |
1680 | timeoutp = &timeout; | |
1681 | } | |
1682 | for (;;) { | |
1683 | if (active_state->packet_timeout_ms != -1) { | |
1684 | ms_to_timeval(&timeout, ms_remain); | |
1685 | gettimeofday(&start, NULL); | |
1686 | } | |
1687 | if ((ret = select(active_state->connection_out + 1, | |
1688 | NULL, setp, NULL, timeoutp)) >= 0) | |
1689 | break; | |
1690 | if (errno != EAGAIN && errno != EINTR && | |
1691 | errno != EWOULDBLOCK) | |
1692 | break; | |
1693 | if (active_state->packet_timeout_ms == -1) | |
1694 | continue; | |
1695 | ms_subtract_diff(&start, &ms_remain); | |
1696 | if (ms_remain <= 0) { | |
1697 | ret = 0; | |
1698 | break; | |
1699 | } | |
1700 | } | |
1701 | if (ret == 0) { | |
1702 | logit("Connection to %.200s timed out while " | |
1703 | "waiting to write", get_remote_ipaddr()); | |
1704 | cleanup_exit(255); | |
1705 | } | |
1706 | packet_write_poll(); | |
1707 | } | |
1708 | xfree(setp); | |
1709 | } | |
1710 | ||
1711 | /* Returns true if there is buffered data to write to the connection. */ | |
1712 | ||
1713 | int | |
1714 | packet_have_data_to_write(void) | |
1715 | { | |
1716 | return buffer_len(&active_state->output) != 0; | |
1717 | } | |
1718 | ||
1719 | /* Returns true if there is not too much data to write to the connection. */ | |
1720 | ||
1721 | int | |
1722 | packet_not_very_much_data_to_write(void) | |
1723 | { | |
1724 | if (active_state->interactive_mode) | |
1725 | return buffer_len(&active_state->output) < 16384; | |
1726 | else | |
1727 | return buffer_len(&active_state->output) < 128 * 1024; | |
1728 | } | |
1729 | ||
1730 | static void | |
1731 | packet_set_tos(int interactive) | |
1732 | { | |
1733 | #if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN) | |
1734 | int tos = interactive ? IPTOS_LOWDELAY : IPTOS_THROUGHPUT; | |
1735 | ||
1736 | if (!packet_connection_is_on_socket() || | |
1737 | !packet_connection_is_ipv4()) | |
1738 | return; | |
1739 | if (setsockopt(active_state->connection_in, IPPROTO_IP, IP_TOS, &tos, | |
1740 | sizeof(tos)) < 0) | |
1741 | error("setsockopt IP_TOS %d: %.100s:", | |
1742 | tos, strerror(errno)); | |
1743 | #endif | |
1744 | } | |
1745 | ||
1746 | /* Informs that the current session is interactive. Sets IP flags for that. */ | |
1747 | ||
1748 | void | |
1749 | packet_set_interactive(int interactive) | |
1750 | { | |
1751 | if (active_state->set_interactive_called) | |
1752 | return; | |
1753 | active_state->set_interactive_called = 1; | |
1754 | ||
1755 | /* Record that we are in interactive mode. */ | |
1756 | active_state->interactive_mode = interactive; | |
1757 | ||
1758 | /* Only set socket options if using a socket. */ | |
1759 | if (!packet_connection_is_on_socket()) | |
1760 | return; | |
1761 | set_nodelay(active_state->connection_in); | |
1762 | packet_set_tos(interactive); | |
1763 | } | |
1764 | ||
1765 | /* Returns true if the current connection is interactive. */ | |
1766 | ||
1767 | int | |
1768 | packet_is_interactive(void) | |
1769 | { | |
1770 | return active_state->interactive_mode; | |
1771 | } | |
1772 | ||
1773 | int | |
1774 | packet_set_maxsize(u_int s) | |
1775 | { | |
1776 | if (active_state->set_maxsize_called) { | |
1777 | logit("packet_set_maxsize: called twice: old %d new %d", | |
1778 | active_state->max_packet_size, s); | |
1779 | return -1; | |
1780 | } | |
1781 | if (s < 4 * 1024 || s > 1024 * 1024) { | |
1782 | logit("packet_set_maxsize: bad size %d", s); | |
1783 | return -1; | |
1784 | } | |
1785 | active_state->set_maxsize_called = 1; | |
1786 | debug("packet_set_maxsize: setting to %d", s); | |
1787 | active_state->max_packet_size = s; | |
1788 | return s; | |
1789 | } | |
1790 | ||
1791 | int | |
1792 | packet_inc_alive_timeouts(void) | |
1793 | { | |
1794 | return ++active_state->keep_alive_timeouts; | |
1795 | } | |
1796 | ||
1797 | void | |
1798 | packet_set_alive_timeouts(int ka) | |
1799 | { | |
1800 | active_state->keep_alive_timeouts = ka; | |
1801 | } | |
1802 | ||
1803 | u_int | |
1804 | packet_get_maxsize(void) | |
1805 | { | |
1806 | return active_state->max_packet_size; | |
1807 | } | |
1808 | ||
1809 | /* roundup current message to pad bytes */ | |
1810 | void | |
1811 | packet_add_padding(u_char pad) | |
1812 | { | |
1813 | active_state->extra_pad = pad; | |
1814 | } | |
1815 | ||
1816 | /* | |
1817 | * 9.2. Ignored Data Message | |
1818 | * | |
1819 | * byte SSH_MSG_IGNORE | |
1820 | * string data | |
1821 | * | |
1822 | * All implementations MUST understand (and ignore) this message at any | |
1823 | * time (after receiving the protocol version). No implementation is | |
1824 | * required to send them. This message can be used as an additional | |
1825 | * protection measure against advanced traffic analysis techniques. | |
1826 | */ | |
1827 | void | |
1828 | packet_send_ignore(int nbytes) | |
1829 | { | |
1830 | u_int32_t rnd = 0; | |
1831 | int i; | |
1832 | ||
1833 | packet_start(compat20 ? SSH2_MSG_IGNORE : SSH_MSG_IGNORE); | |
1834 | packet_put_int(nbytes); | |
1835 | for (i = 0; i < nbytes; i++) { | |
1836 | if (i % 4 == 0) | |
1837 | rnd = arc4random(); | |
1838 | packet_put_char((u_char)rnd & 0xff); | |
1839 | rnd >>= 8; | |
1840 | } | |
1841 | } | |
1842 | ||
1843 | #define MAX_PACKETS (1U<<31) | |
1844 | int | |
1845 | packet_need_rekeying(void) | |
1846 | { | |
1847 | if (datafellows & SSH_BUG_NOREKEY) | |
1848 | return 0; | |
1849 | return | |
1850 | (active_state->p_send.packets > MAX_PACKETS) || | |
1851 | (active_state->p_read.packets > MAX_PACKETS) || | |
1852 | (active_state->max_blocks_out && | |
1853 | (active_state->p_send.blocks > active_state->max_blocks_out)) || | |
1854 | (active_state->max_blocks_in && | |
1855 | (active_state->p_read.blocks > active_state->max_blocks_in)); | |
1856 | } | |
1857 | ||
1858 | void | |
1859 | packet_set_rekey_limit(u_int32_t bytes) | |
1860 | { | |
1861 | active_state->rekey_limit = bytes; | |
1862 | } | |
1863 | ||
1864 | void | |
1865 | packet_set_server(void) | |
1866 | { | |
1867 | active_state->server_side = 1; | |
1868 | } | |
1869 | ||
1870 | void | |
1871 | packet_set_authenticated(void) | |
1872 | { | |
1873 | active_state->after_authentication = 1; | |
1874 | } | |
1875 | ||
1876 | void * | |
1877 | packet_get_input(void) | |
1878 | { | |
1879 | return (void *)&active_state->input; | |
1880 | } | |
1881 | ||
1882 | void * | |
1883 | packet_get_output(void) | |
1884 | { | |
1885 | return (void *)&active_state->output; | |
1886 | } | |
1887 | ||
1888 | void * | |
1889 | packet_get_newkeys(int mode) | |
1890 | { | |
1891 | return (void *)active_state->newkeys[mode]; | |
1892 | } | |
1893 | ||
1894 | /* | |
1895 | * Save the state for the real connection, and use a separate state when | |
1896 | * resuming a suspended connection. | |
1897 | */ | |
1898 | void | |
1899 | packet_backup_state(void) | |
1900 | { | |
1901 | struct session_state *tmp; | |
1902 | ||
1903 | close(active_state->connection_in); | |
1904 | active_state->connection_in = -1; | |
1905 | close(active_state->connection_out); | |
1906 | active_state->connection_out = -1; | |
1907 | if (backup_state) | |
1908 | tmp = backup_state; | |
1909 | else | |
1910 | tmp = alloc_session_state(); | |
1911 | backup_state = active_state; | |
1912 | active_state = tmp; | |
1913 | } | |
1914 | ||
1915 | /* | |
1916 | * Swap in the old state when resuming a connecion. | |
1917 | */ | |
1918 | void | |
1919 | packet_restore_state(void) | |
1920 | { | |
1921 | struct session_state *tmp; | |
1922 | void *buf; | |
1923 | u_int len; | |
1924 | ||
1925 | tmp = backup_state; | |
1926 | backup_state = active_state; | |
1927 | active_state = tmp; | |
1928 | active_state->connection_in = backup_state->connection_in; | |
1929 | backup_state->connection_in = -1; | |
1930 | active_state->connection_out = backup_state->connection_out; | |
1931 | backup_state->connection_out = -1; | |
1932 | len = buffer_len(&backup_state->input); | |
1933 | if (len > 0) { | |
1934 | buf = buffer_ptr(&backup_state->input); | |
1935 | buffer_append(&active_state->input, buf, len); | |
1936 | buffer_clear(&backup_state->input); | |
1937 | add_recv_bytes(len); | |
1938 | } | |
1939 | } |