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1 | /* $OpenBSD: packet.c,v 1.163 2009/05/28 16:50:16 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 | TAILQ_HEAD(, packet) outgoing; | |
186 | }; | |
187 | ||
188 | static struct session_state *active_state; | |
189 | ||
190 | static struct session_state * | |
191 | alloc_session_state() | |
192 | { | |
193 | struct session_state *s = xcalloc(1, sizeof(*s)); | |
194 | ||
195 | s->connection_in = -1; | |
196 | s->connection_out = -1; | |
197 | s->max_packet_size = 32768; | |
198 | s->packet_timeout_ms = -1; | |
199 | return s; | |
200 | } | |
201 | ||
202 | /* | |
203 | * Sets the descriptors used for communication. Disables encryption until | |
204 | * packet_set_encryption_key is called. | |
205 | */ | |
206 | void | |
207 | packet_set_connection(int fd_in, int fd_out) | |
208 | { | |
209 | Cipher *none = cipher_by_name("none"); | |
210 | ||
211 | if (none == NULL) | |
212 | fatal("packet_set_connection: cannot load cipher 'none'"); | |
213 | if (active_state == NULL) | |
214 | active_state = alloc_session_state(); | |
215 | active_state->connection_in = fd_in; | |
216 | active_state->connection_out = fd_out; | |
217 | cipher_init(&active_state->send_context, none, (const u_char *)"", | |
218 | 0, NULL, 0, CIPHER_ENCRYPT); | |
219 | cipher_init(&active_state->receive_context, none, (const u_char *)"", | |
220 | 0, NULL, 0, CIPHER_DECRYPT); | |
221 | active_state->newkeys[MODE_IN] = active_state->newkeys[MODE_OUT] = NULL; | |
222 | if (!active_state->initialized) { | |
223 | active_state->initialized = 1; | |
224 | buffer_init(&active_state->input); | |
225 | buffer_init(&active_state->output); | |
226 | buffer_init(&active_state->outgoing_packet); | |
227 | buffer_init(&active_state->incoming_packet); | |
228 | TAILQ_INIT(&active_state->outgoing); | |
229 | active_state->p_send.packets = active_state->p_read.packets = 0; | |
230 | } | |
231 | } | |
232 | ||
233 | void | |
234 | packet_set_timeout(int timeout, int count) | |
235 | { | |
236 | if (timeout == 0 || count == 0) { | |
237 | active_state->packet_timeout_ms = -1; | |
238 | return; | |
239 | } | |
240 | if ((INT_MAX / 1000) / count < timeout) | |
241 | active_state->packet_timeout_ms = INT_MAX; | |
242 | else | |
243 | active_state->packet_timeout_ms = timeout * count * 1000; | |
244 | } | |
245 | ||
246 | static void | |
247 | packet_stop_discard(void) | |
248 | { | |
249 | if (active_state->packet_discard_mac) { | |
250 | char buf[1024]; | |
251 | ||
252 | memset(buf, 'a', sizeof(buf)); | |
253 | while (buffer_len(&active_state->incoming_packet) < | |
254 | PACKET_MAX_SIZE) | |
255 | buffer_append(&active_state->incoming_packet, buf, | |
256 | sizeof(buf)); | |
257 | (void) mac_compute(active_state->packet_discard_mac, | |
258 | active_state->p_read.seqnr, | |
259 | buffer_ptr(&active_state->incoming_packet), | |
260 | PACKET_MAX_SIZE); | |
261 | } | |
262 | logit("Finished discarding for %.200s", get_remote_ipaddr()); | |
263 | cleanup_exit(255); | |
264 | } | |
265 | ||
266 | static void | |
267 | packet_start_discard(Enc *enc, Mac *mac, u_int packet_length, u_int discard) | |
268 | { | |
269 | if (enc == NULL || !cipher_is_cbc(enc->cipher)) | |
270 | packet_disconnect("Packet corrupt"); | |
271 | if (packet_length != PACKET_MAX_SIZE && mac && mac->enabled) | |
272 | active_state->packet_discard_mac = mac; | |
273 | if (buffer_len(&active_state->input) >= discard) | |
274 | packet_stop_discard(); | |
275 | active_state->packet_discard = discard - | |
276 | buffer_len(&active_state->input); | |
277 | } | |
278 | ||
279 | /* Returns 1 if remote host is connected via socket, 0 if not. */ | |
280 | ||
281 | int | |
282 | packet_connection_is_on_socket(void) | |
283 | { | |
284 | struct sockaddr_storage from, to; | |
285 | socklen_t fromlen, tolen; | |
286 | ||
287 | /* filedescriptors in and out are the same, so it's a socket */ | |
288 | if (active_state->connection_in == active_state->connection_out) | |
289 | return 1; | |
290 | fromlen = sizeof(from); | |
291 | memset(&from, 0, sizeof(from)); | |
292 | if (getpeername(active_state->connection_in, (struct sockaddr *)&from, | |
293 | &fromlen) < 0) | |
294 | return 0; | |
295 | tolen = sizeof(to); | |
296 | memset(&to, 0, sizeof(to)); | |
297 | if (getpeername(active_state->connection_out, (struct sockaddr *)&to, | |
298 | &tolen) < 0) | |
299 | return 0; | |
300 | if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0) | |
301 | return 0; | |
302 | if (from.ss_family != AF_INET && from.ss_family != AF_INET6) | |
303 | return 0; | |
304 | return 1; | |
305 | } | |
306 | ||
307 | /* | |
308 | * Exports an IV from the CipherContext required to export the key | |
309 | * state back from the unprivileged child to the privileged parent | |
310 | * process. | |
311 | */ | |
312 | ||
313 | void | |
314 | packet_get_keyiv(int mode, u_char *iv, u_int len) | |
315 | { | |
316 | CipherContext *cc; | |
317 | ||
318 | if (mode == MODE_OUT) | |
319 | cc = &active_state->send_context; | |
320 | else | |
321 | cc = &active_state->receive_context; | |
322 | ||
323 | cipher_get_keyiv(cc, iv, len); | |
324 | } | |
325 | ||
326 | int | |
327 | packet_get_keycontext(int mode, u_char *dat) | |
328 | { | |
329 | CipherContext *cc; | |
330 | ||
331 | if (mode == MODE_OUT) | |
332 | cc = &active_state->send_context; | |
333 | else | |
334 | cc = &active_state->receive_context; | |
335 | ||
336 | return (cipher_get_keycontext(cc, dat)); | |
337 | } | |
338 | ||
339 | void | |
340 | packet_set_keycontext(int mode, u_char *dat) | |
341 | { | |
342 | CipherContext *cc; | |
343 | ||
344 | if (mode == MODE_OUT) | |
345 | cc = &active_state->send_context; | |
346 | else | |
347 | cc = &active_state->receive_context; | |
348 | ||
349 | cipher_set_keycontext(cc, dat); | |
350 | } | |
351 | ||
352 | int | |
353 | packet_get_keyiv_len(int mode) | |
354 | { | |
355 | CipherContext *cc; | |
356 | ||
357 | if (mode == MODE_OUT) | |
358 | cc = &active_state->send_context; | |
359 | else | |
360 | cc = &active_state->receive_context; | |
361 | ||
362 | return (cipher_get_keyiv_len(cc)); | |
363 | } | |
364 | ||
365 | void | |
366 | packet_set_iv(int mode, u_char *dat) | |
367 | { | |
368 | CipherContext *cc; | |
369 | ||
370 | if (mode == MODE_OUT) | |
371 | cc = &active_state->send_context; | |
372 | else | |
373 | cc = &active_state->receive_context; | |
374 | ||
375 | cipher_set_keyiv(cc, dat); | |
376 | } | |
377 | ||
378 | int | |
379 | packet_get_ssh1_cipher(void) | |
380 | { | |
381 | return (cipher_get_number(active_state->receive_context.cipher)); | |
382 | } | |
383 | ||
384 | void | |
385 | packet_get_state(int mode, u_int32_t *seqnr, u_int64_t *blocks, u_int32_t *packets, | |
386 | u_int64_t *bytes) | |
387 | { | |
388 | struct packet_state *state; | |
389 | ||
390 | state = (mode == MODE_IN) ? | |
391 | &active_state->p_read : &active_state->p_send; | |
392 | if (seqnr) | |
393 | *seqnr = state->seqnr; | |
394 | if (blocks) | |
395 | *blocks = state->blocks; | |
396 | if (packets) | |
397 | *packets = state->packets; | |
398 | if (bytes) | |
399 | *bytes = state->bytes; | |
400 | } | |
401 | ||
402 | void | |
403 | packet_set_state(int mode, u_int32_t seqnr, u_int64_t blocks, u_int32_t packets, | |
404 | u_int64_t bytes) | |
405 | { | |
406 | struct packet_state *state; | |
407 | ||
408 | state = (mode == MODE_IN) ? | |
409 | &active_state->p_read : &active_state->p_send; | |
410 | state->seqnr = seqnr; | |
411 | state->blocks = blocks; | |
412 | state->packets = packets; | |
413 | state->bytes = bytes; | |
414 | } | |
415 | ||
416 | /* returns 1 if connection is via ipv4 */ | |
417 | ||
418 | int | |
419 | packet_connection_is_ipv4(void) | |
420 | { | |
421 | struct sockaddr_storage to; | |
422 | socklen_t tolen = sizeof(to); | |
423 | ||
424 | memset(&to, 0, sizeof(to)); | |
425 | if (getsockname(active_state->connection_out, (struct sockaddr *)&to, | |
426 | &tolen) < 0) | |
427 | return 0; | |
428 | if (to.ss_family == AF_INET) | |
429 | return 1; | |
430 | #ifdef IPV4_IN_IPV6 | |
431 | if (to.ss_family == AF_INET6 && | |
432 | IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)&to)->sin6_addr)) | |
433 | return 1; | |
434 | #endif | |
435 | return 0; | |
436 | } | |
437 | ||
438 | /* Sets the connection into non-blocking mode. */ | |
439 | ||
440 | void | |
441 | packet_set_nonblocking(void) | |
442 | { | |
443 | /* Set the socket into non-blocking mode. */ | |
444 | set_nonblock(active_state->connection_in); | |
445 | ||
446 | if (active_state->connection_out != active_state->connection_in) | |
447 | set_nonblock(active_state->connection_out); | |
448 | } | |
449 | ||
450 | /* Returns the socket used for reading. */ | |
451 | ||
452 | int | |
453 | packet_get_connection_in(void) | |
454 | { | |
455 | return active_state->connection_in; | |
456 | } | |
457 | ||
458 | /* Returns the descriptor used for writing. */ | |
459 | ||
460 | int | |
461 | packet_get_connection_out(void) | |
462 | { | |
463 | return active_state->connection_out; | |
464 | } | |
465 | ||
466 | /* Closes the connection and clears and frees internal data structures. */ | |
467 | ||
468 | void | |
469 | packet_close(void) | |
470 | { | |
471 | if (!active_state->initialized) | |
472 | return; | |
473 | active_state->initialized = 0; | |
474 | if (active_state->connection_in == active_state->connection_out) { | |
475 | shutdown(active_state->connection_out, SHUT_RDWR); | |
476 | close(active_state->connection_out); | |
477 | } else { | |
478 | close(active_state->connection_in); | |
479 | close(active_state->connection_out); | |
480 | } | |
481 | buffer_free(&active_state->input); | |
482 | buffer_free(&active_state->output); | |
483 | buffer_free(&active_state->outgoing_packet); | |
484 | buffer_free(&active_state->incoming_packet); | |
485 | if (active_state->compression_buffer_ready) { | |
486 | buffer_free(&active_state->compression_buffer); | |
487 | buffer_compress_uninit(); | |
488 | } | |
489 | cipher_cleanup(&active_state->send_context); | |
490 | cipher_cleanup(&active_state->receive_context); | |
491 | } | |
492 | ||
493 | /* Sets remote side protocol flags. */ | |
494 | ||
495 | void | |
496 | packet_set_protocol_flags(u_int protocol_flags) | |
497 | { | |
498 | active_state->remote_protocol_flags = protocol_flags; | |
499 | } | |
500 | ||
501 | /* Returns the remote protocol flags set earlier by the above function. */ | |
502 | ||
503 | u_int | |
504 | packet_get_protocol_flags(void) | |
505 | { | |
506 | return active_state->remote_protocol_flags; | |
507 | } | |
508 | ||
509 | /* | |
510 | * Starts packet compression from the next packet on in both directions. | |
511 | * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip. | |
512 | */ | |
513 | ||
514 | static void | |
515 | packet_init_compression(void) | |
516 | { | |
517 | if (active_state->compression_buffer_ready == 1) | |
518 | return; | |
519 | active_state->compression_buffer_ready = 1; | |
520 | buffer_init(&active_state->compression_buffer); | |
521 | } | |
522 | ||
523 | void | |
524 | packet_start_compression(int level) | |
525 | { | |
526 | if (active_state->packet_compression && !compat20) | |
527 | fatal("Compression already enabled."); | |
528 | active_state->packet_compression = 1; | |
529 | packet_init_compression(); | |
530 | buffer_compress_init_send(level); | |
531 | buffer_compress_init_recv(); | |
532 | } | |
533 | ||
534 | /* | |
535 | * Causes any further packets to be encrypted using the given key. The same | |
536 | * key is used for both sending and reception. However, both directions are | |
537 | * encrypted independently of each other. | |
538 | */ | |
539 | ||
540 | void | |
541 | packet_set_encryption_key(const u_char *key, u_int keylen, | |
542 | int number) | |
543 | { | |
544 | Cipher *cipher = cipher_by_number(number); | |
545 | ||
546 | if (cipher == NULL) | |
547 | fatal("packet_set_encryption_key: unknown cipher number %d", number); | |
548 | if (keylen < 20) | |
549 | fatal("packet_set_encryption_key: keylen too small: %d", keylen); | |
550 | if (keylen > SSH_SESSION_KEY_LENGTH) | |
551 | fatal("packet_set_encryption_key: keylen too big: %d", keylen); | |
552 | memcpy(active_state->ssh1_key, key, keylen); | |
553 | active_state->ssh1_keylen = keylen; | |
554 | cipher_init(&active_state->send_context, cipher, key, keylen, NULL, | |
555 | 0, CIPHER_ENCRYPT); | |
556 | cipher_init(&active_state->receive_context, cipher, key, keylen, NULL, | |
557 | 0, CIPHER_DECRYPT); | |
558 | } | |
559 | ||
560 | u_int | |
561 | packet_get_encryption_key(u_char *key) | |
562 | { | |
563 | if (key == NULL) | |
564 | return (active_state->ssh1_keylen); | |
565 | memcpy(key, active_state->ssh1_key, active_state->ssh1_keylen); | |
566 | return (active_state->ssh1_keylen); | |
567 | } | |
568 | ||
569 | /* Start constructing a packet to send. */ | |
570 | void | |
571 | packet_start(u_char type) | |
572 | { | |
573 | u_char buf[9]; | |
574 | int len; | |
575 | ||
576 | DBG(debug("packet_start[%d]", type)); | |
577 | len = compat20 ? 6 : 9; | |
578 | memset(buf, 0, len - 1); | |
579 | buf[len - 1] = type; | |
580 | buffer_clear(&active_state->outgoing_packet); | |
581 | buffer_append(&active_state->outgoing_packet, buf, len); | |
582 | } | |
583 | ||
584 | /* Append payload. */ | |
585 | void | |
586 | packet_put_char(int value) | |
587 | { | |
588 | char ch = value; | |
589 | ||
590 | buffer_append(&active_state->outgoing_packet, &ch, 1); | |
591 | } | |
592 | ||
593 | void | |
594 | packet_put_int(u_int value) | |
595 | { | |
596 | buffer_put_int(&active_state->outgoing_packet, value); | |
597 | } | |
598 | ||
599 | void | |
600 | packet_put_int64(u_int64_t value) | |
601 | { | |
602 | buffer_put_int64(&active_state->outgoing_packet, value); | |
603 | } | |
604 | ||
605 | void | |
606 | packet_put_string(const void *buf, u_int len) | |
607 | { | |
608 | buffer_put_string(&active_state->outgoing_packet, buf, len); | |
609 | } | |
610 | ||
611 | void | |
612 | packet_put_cstring(const char *str) | |
613 | { | |
614 | buffer_put_cstring(&active_state->outgoing_packet, str); | |
615 | } | |
616 | ||
617 | void | |
618 | packet_put_raw(const void *buf, u_int len) | |
619 | { | |
620 | buffer_append(&active_state->outgoing_packet, buf, len); | |
621 | } | |
622 | ||
623 | void | |
624 | packet_put_bignum(BIGNUM * value) | |
625 | { | |
626 | buffer_put_bignum(&active_state->outgoing_packet, value); | |
627 | } | |
628 | ||
629 | void | |
630 | packet_put_bignum2(BIGNUM * value) | |
631 | { | |
632 | buffer_put_bignum2(&active_state->outgoing_packet, value); | |
633 | } | |
634 | ||
635 | /* | |
636 | * Finalizes and sends the packet. If the encryption key has been set, | |
637 | * encrypts the packet before sending. | |
638 | */ | |
639 | ||
640 | static void | |
641 | packet_send1(void) | |
642 | { | |
643 | u_char buf[8], *cp; | |
644 | int i, padding, len; | |
645 | u_int checksum; | |
646 | u_int32_t rnd = 0; | |
647 | ||
648 | /* | |
649 | * If using packet compression, compress the payload of the outgoing | |
650 | * packet. | |
651 | */ | |
652 | if (active_state->packet_compression) { | |
653 | buffer_clear(&active_state->compression_buffer); | |
654 | /* Skip padding. */ | |
655 | buffer_consume(&active_state->outgoing_packet, 8); | |
656 | /* padding */ | |
657 | buffer_append(&active_state->compression_buffer, | |
658 | "\0\0\0\0\0\0\0\0", 8); | |
659 | buffer_compress(&active_state->outgoing_packet, | |
660 | &active_state->compression_buffer); | |
661 | buffer_clear(&active_state->outgoing_packet); | |
662 | buffer_append(&active_state->outgoing_packet, | |
663 | buffer_ptr(&active_state->compression_buffer), | |
664 | buffer_len(&active_state->compression_buffer)); | |
665 | } | |
666 | /* Compute packet length without padding (add checksum, remove padding). */ | |
667 | len = buffer_len(&active_state->outgoing_packet) + 4 - 8; | |
668 | ||
669 | /* Insert padding. Initialized to zero in packet_start1() */ | |
670 | padding = 8 - len % 8; | |
671 | if (!active_state->send_context.plaintext) { | |
672 | cp = buffer_ptr(&active_state->outgoing_packet); | |
673 | for (i = 0; i < padding; i++) { | |
674 | if (i % 4 == 0) | |
675 | rnd = arc4random(); | |
676 | cp[7 - i] = rnd & 0xff; | |
677 | rnd >>= 8; | |
678 | } | |
679 | } | |
680 | buffer_consume(&active_state->outgoing_packet, 8 - padding); | |
681 | ||
682 | /* Add check bytes. */ | |
683 | checksum = ssh_crc32(buffer_ptr(&active_state->outgoing_packet), | |
684 | buffer_len(&active_state->outgoing_packet)); | |
685 | put_u32(buf, checksum); | |
686 | buffer_append(&active_state->outgoing_packet, buf, 4); | |
687 | ||
688 | #ifdef PACKET_DEBUG | |
689 | fprintf(stderr, "packet_send plain: "); | |
690 | buffer_dump(&active_state->outgoing_packet); | |
691 | #endif | |
692 | ||
693 | /* Append to output. */ | |
694 | put_u32(buf, len); | |
695 | buffer_append(&active_state->output, buf, 4); | |
696 | cp = buffer_append_space(&active_state->output, | |
697 | buffer_len(&active_state->outgoing_packet)); | |
698 | cipher_crypt(&active_state->send_context, cp, | |
699 | buffer_ptr(&active_state->outgoing_packet), | |
700 | buffer_len(&active_state->outgoing_packet)); | |
701 | ||
702 | #ifdef PACKET_DEBUG | |
703 | fprintf(stderr, "encrypted: "); | |
704 | buffer_dump(&active_state->output); | |
705 | #endif | |
706 | active_state->p_send.packets++; | |
707 | active_state->p_send.bytes += len + | |
708 | buffer_len(&active_state->outgoing_packet); | |
709 | buffer_clear(&active_state->outgoing_packet); | |
710 | ||
711 | /* | |
712 | * Note that the packet is now only buffered in output. It won't be | |
713 | * actually sent until packet_write_wait or packet_write_poll is | |
714 | * called. | |
715 | */ | |
716 | } | |
717 | ||
718 | void | |
719 | set_newkeys(int mode) | |
720 | { | |
721 | Enc *enc; | |
722 | Mac *mac; | |
723 | Comp *comp; | |
724 | CipherContext *cc; | |
725 | u_int64_t *max_blocks; | |
726 | int crypt_type; | |
727 | ||
728 | debug2("set_newkeys: mode %d", mode); | |
729 | ||
730 | if (mode == MODE_OUT) { | |
731 | cc = &active_state->send_context; | |
732 | crypt_type = CIPHER_ENCRYPT; | |
733 | active_state->p_send.packets = active_state->p_send.blocks = 0; | |
734 | max_blocks = &active_state->max_blocks_out; | |
735 | } else { | |
736 | cc = &active_state->receive_context; | |
737 | crypt_type = CIPHER_DECRYPT; | |
738 | active_state->p_read.packets = active_state->p_read.blocks = 0; | |
739 | max_blocks = &active_state->max_blocks_in; | |
740 | } | |
741 | if (active_state->newkeys[mode] != NULL) { | |
742 | debug("set_newkeys: rekeying"); | |
743 | cipher_cleanup(cc); | |
744 | enc = &active_state->newkeys[mode]->enc; | |
745 | mac = &active_state->newkeys[mode]->mac; | |
746 | comp = &active_state->newkeys[mode]->comp; | |
747 | mac_clear(mac); | |
748 | xfree(enc->name); | |
749 | xfree(enc->iv); | |
750 | xfree(enc->key); | |
751 | xfree(mac->name); | |
752 | xfree(mac->key); | |
753 | xfree(comp->name); | |
754 | xfree(active_state->newkeys[mode]); | |
755 | } | |
756 | active_state->newkeys[mode] = kex_get_newkeys(mode); | |
757 | if (active_state->newkeys[mode] == NULL) | |
758 | fatal("newkeys: no keys for mode %d", mode); | |
759 | enc = &active_state->newkeys[mode]->enc; | |
760 | mac = &active_state->newkeys[mode]->mac; | |
761 | comp = &active_state->newkeys[mode]->comp; | |
762 | if (mac_init(mac) == 0) | |
763 | mac->enabled = 1; | |
764 | DBG(debug("cipher_init_context: %d", mode)); | |
765 | cipher_init(cc, enc->cipher, enc->key, enc->key_len, | |
766 | enc->iv, enc->block_size, crypt_type); | |
767 | /* Deleting the keys does not gain extra security */ | |
768 | /* memset(enc->iv, 0, enc->block_size); | |
769 | memset(enc->key, 0, enc->key_len); | |
770 | memset(mac->key, 0, mac->key_len); */ | |
771 | if ((comp->type == COMP_ZLIB || | |
772 | (comp->type == COMP_DELAYED && | |
773 | active_state->after_authentication)) && comp->enabled == 0) { | |
774 | packet_init_compression(); | |
775 | if (mode == MODE_OUT) | |
776 | buffer_compress_init_send(6); | |
777 | else | |
778 | buffer_compress_init_recv(); | |
779 | comp->enabled = 1; | |
780 | } | |
781 | /* | |
782 | * The 2^(blocksize*2) limit is too expensive for 3DES, | |
783 | * blowfish, etc, so enforce a 1GB limit for small blocksizes. | |
784 | */ | |
785 | if (enc->block_size >= 16) | |
786 | *max_blocks = (u_int64_t)1 << (enc->block_size*2); | |
787 | else | |
788 | *max_blocks = ((u_int64_t)1 << 30) / enc->block_size; | |
789 | if (active_state->rekey_limit) | |
790 | *max_blocks = MIN(*max_blocks, | |
791 | active_state->rekey_limit / enc->block_size); | |
792 | } | |
793 | ||
794 | /* | |
795 | * Delayed compression for SSH2 is enabled after authentication: | |
796 | * This happens on the server side after a SSH2_MSG_USERAUTH_SUCCESS is sent, | |
797 | * and on the client side after a SSH2_MSG_USERAUTH_SUCCESS is received. | |
798 | */ | |
799 | static void | |
800 | packet_enable_delayed_compress(void) | |
801 | { | |
802 | Comp *comp = NULL; | |
803 | int mode; | |
804 | ||
805 | /* | |
806 | * Remember that we are past the authentication step, so rekeying | |
807 | * with COMP_DELAYED will turn on compression immediately. | |
808 | */ | |
809 | active_state->after_authentication = 1; | |
810 | for (mode = 0; mode < MODE_MAX; mode++) { | |
811 | /* protocol error: USERAUTH_SUCCESS received before NEWKEYS */ | |
812 | if (active_state->newkeys[mode] == NULL) | |
813 | continue; | |
814 | comp = &active_state->newkeys[mode]->comp; | |
815 | if (comp && !comp->enabled && comp->type == COMP_DELAYED) { | |
816 | packet_init_compression(); | |
817 | if (mode == MODE_OUT) | |
818 | buffer_compress_init_send(6); | |
819 | else | |
820 | buffer_compress_init_recv(); | |
821 | comp->enabled = 1; | |
822 | } | |
823 | } | |
824 | } | |
825 | ||
826 | /* | |
827 | * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue) | |
828 | */ | |
829 | static void | |
830 | packet_send2_wrapped(void) | |
831 | { | |
832 | u_char type, *cp, *macbuf = NULL; | |
833 | u_char padlen, pad; | |
834 | u_int packet_length = 0; | |
835 | u_int i, len; | |
836 | u_int32_t rnd = 0; | |
837 | Enc *enc = NULL; | |
838 | Mac *mac = NULL; | |
839 | Comp *comp = NULL; | |
840 | int block_size; | |
841 | ||
842 | if (active_state->newkeys[MODE_OUT] != NULL) { | |
843 | enc = &active_state->newkeys[MODE_OUT]->enc; | |
844 | mac = &active_state->newkeys[MODE_OUT]->mac; | |
845 | comp = &active_state->newkeys[MODE_OUT]->comp; | |
846 | } | |
847 | block_size = enc ? enc->block_size : 8; | |
848 | ||
849 | cp = buffer_ptr(&active_state->outgoing_packet); | |
850 | type = cp[5]; | |
851 | ||
852 | #ifdef PACKET_DEBUG | |
853 | fprintf(stderr, "plain: "); | |
854 | buffer_dump(&active_state->outgoing_packet); | |
855 | #endif | |
856 | ||
857 | if (comp && comp->enabled) { | |
858 | len = buffer_len(&active_state->outgoing_packet); | |
859 | /* skip header, compress only payload */ | |
860 | buffer_consume(&active_state->outgoing_packet, 5); | |
861 | buffer_clear(&active_state->compression_buffer); | |
862 | buffer_compress(&active_state->outgoing_packet, | |
863 | &active_state->compression_buffer); | |
864 | buffer_clear(&active_state->outgoing_packet); | |
865 | buffer_append(&active_state->outgoing_packet, "\0\0\0\0\0", 5); | |
866 | buffer_append(&active_state->outgoing_packet, | |
867 | buffer_ptr(&active_state->compression_buffer), | |
868 | buffer_len(&active_state->compression_buffer)); | |
869 | DBG(debug("compression: raw %d compressed %d", len, | |
870 | buffer_len(&active_state->outgoing_packet))); | |
871 | } | |
872 | ||
873 | /* sizeof (packet_len + pad_len + payload) */ | |
874 | len = buffer_len(&active_state->outgoing_packet); | |
875 | ||
876 | /* | |
877 | * calc size of padding, alloc space, get random data, | |
878 | * minimum padding is 4 bytes | |
879 | */ | |
880 | padlen = block_size - (len % block_size); | |
881 | if (padlen < 4) | |
882 | padlen += block_size; | |
883 | if (active_state->extra_pad) { | |
884 | /* will wrap if extra_pad+padlen > 255 */ | |
885 | active_state->extra_pad = | |
886 | roundup(active_state->extra_pad, block_size); | |
887 | pad = active_state->extra_pad - | |
888 | ((len + padlen) % active_state->extra_pad); | |
889 | debug3("packet_send2: adding %d (len %d padlen %d extra_pad %d)", | |
890 | pad, len, padlen, active_state->extra_pad); | |
891 | padlen += pad; | |
892 | active_state->extra_pad = 0; | |
893 | } | |
894 | cp = buffer_append_space(&active_state->outgoing_packet, padlen); | |
895 | if (enc && !active_state->send_context.plaintext) { | |
896 | /* random padding */ | |
897 | for (i = 0; i < padlen; i++) { | |
898 | if (i % 4 == 0) | |
899 | rnd = arc4random(); | |
900 | cp[i] = rnd & 0xff; | |
901 | rnd >>= 8; | |
902 | } | |
903 | } else { | |
904 | /* clear padding */ | |
905 | memset(cp, 0, padlen); | |
906 | } | |
907 | /* packet_length includes payload, padding and padding length field */ | |
908 | packet_length = buffer_len(&active_state->outgoing_packet) - 4; | |
909 | cp = buffer_ptr(&active_state->outgoing_packet); | |
910 | put_u32(cp, packet_length); | |
911 | cp[4] = padlen; | |
912 | DBG(debug("send: len %d (includes padlen %d)", packet_length+4, padlen)); | |
913 | ||
914 | /* compute MAC over seqnr and packet(length fields, payload, padding) */ | |
915 | if (mac && mac->enabled) { | |
916 | macbuf = mac_compute(mac, active_state->p_send.seqnr, | |
917 | buffer_ptr(&active_state->outgoing_packet), | |
918 | buffer_len(&active_state->outgoing_packet)); | |
919 | DBG(debug("done calc MAC out #%d", active_state->p_send.seqnr)); | |
920 | } | |
921 | /* encrypt packet and append to output buffer. */ | |
922 | cp = buffer_append_space(&active_state->output, | |
923 | buffer_len(&active_state->outgoing_packet)); | |
924 | cipher_crypt(&active_state->send_context, cp, | |
925 | buffer_ptr(&active_state->outgoing_packet), | |
926 | buffer_len(&active_state->outgoing_packet)); | |
927 | /* append unencrypted MAC */ | |
928 | if (mac && mac->enabled) | |
929 | buffer_append(&active_state->output, macbuf, mac->mac_len); | |
930 | #ifdef PACKET_DEBUG | |
931 | fprintf(stderr, "encrypted: "); | |
932 | buffer_dump(&active_state->output); | |
933 | #endif | |
934 | /* increment sequence number for outgoing packets */ | |
935 | if (++active_state->p_send.seqnr == 0) | |
936 | logit("outgoing seqnr wraps around"); | |
937 | if (++active_state->p_send.packets == 0) | |
938 | if (!(datafellows & SSH_BUG_NOREKEY)) | |
939 | fatal("XXX too many packets with same key"); | |
940 | active_state->p_send.blocks += (packet_length + 4) / block_size; | |
941 | active_state->p_send.bytes += packet_length + 4; | |
942 | buffer_clear(&active_state->outgoing_packet); | |
943 | ||
944 | if (type == SSH2_MSG_NEWKEYS) | |
945 | set_newkeys(MODE_OUT); | |
946 | else if (type == SSH2_MSG_USERAUTH_SUCCESS && active_state->server_side) | |
947 | packet_enable_delayed_compress(); | |
948 | } | |
949 | ||
950 | static void | |
951 | packet_send2(void) | |
952 | { | |
953 | static int rekeying = 0; | |
954 | struct packet *p; | |
955 | u_char type, *cp; | |
956 | ||
957 | cp = buffer_ptr(&active_state->outgoing_packet); | |
958 | type = cp[5]; | |
959 | ||
960 | /* during rekeying we can only send key exchange messages */ | |
961 | if (rekeying) { | |
962 | if (!((type >= SSH2_MSG_TRANSPORT_MIN) && | |
963 | (type <= SSH2_MSG_TRANSPORT_MAX))) { | |
964 | debug("enqueue packet: %u", type); | |
965 | p = xmalloc(sizeof(*p)); | |
966 | p->type = type; | |
967 | memcpy(&p->payload, &active_state->outgoing_packet, | |
968 | sizeof(Buffer)); | |
969 | buffer_init(&active_state->outgoing_packet); | |
970 | TAILQ_INSERT_TAIL(&active_state->outgoing, p, next); | |
971 | return; | |
972 | } | |
973 | } | |
974 | ||
975 | /* rekeying starts with sending KEXINIT */ | |
976 | if (type == SSH2_MSG_KEXINIT) | |
977 | rekeying = 1; | |
978 | ||
979 | packet_send2_wrapped(); | |
980 | ||
981 | /* after a NEWKEYS message we can send the complete queue */ | |
982 | if (type == SSH2_MSG_NEWKEYS) { | |
983 | rekeying = 0; | |
984 | while ((p = TAILQ_FIRST(&active_state->outgoing))) { | |
985 | type = p->type; | |
986 | debug("dequeue packet: %u", type); | |
987 | buffer_free(&active_state->outgoing_packet); | |
988 | memcpy(&active_state->outgoing_packet, &p->payload, | |
989 | sizeof(Buffer)); | |
990 | TAILQ_REMOVE(&active_state->outgoing, p, next); | |
991 | xfree(p); | |
992 | packet_send2_wrapped(); | |
993 | } | |
994 | } | |
995 | } | |
996 | ||
997 | void | |
998 | packet_send(void) | |
999 | { | |
1000 | if (compat20) | |
1001 | packet_send2(); | |
1002 | else | |
1003 | packet_send1(); | |
1004 | DBG(debug("packet_send done")); | |
1005 | } | |
1006 | ||
1007 | /* | |
1008 | * Waits until a packet has been received, and returns its type. Note that | |
1009 | * no other data is processed until this returns, so this function should not | |
1010 | * be used during the interactive session. | |
1011 | */ | |
1012 | ||
1013 | int | |
1014 | packet_read_seqnr(u_int32_t *seqnr_p) | |
1015 | { | |
1016 | int type, len, ret, ms_remain, cont; | |
1017 | fd_set *setp; | |
1018 | char buf[8192]; | |
1019 | struct timeval timeout, start, *timeoutp = NULL; | |
1020 | ||
1021 | DBG(debug("packet_read()")); | |
1022 | ||
1023 | setp = (fd_set *)xcalloc(howmany(active_state->connection_in + 1, | |
1024 | NFDBITS), sizeof(fd_mask)); | |
1025 | ||
1026 | /* Since we are blocking, ensure that all written packets have been sent. */ | |
1027 | packet_write_wait(); | |
1028 | ||
1029 | /* Stay in the loop until we have received a complete packet. */ | |
1030 | for (;;) { | |
1031 | /* Try to read a packet from the buffer. */ | |
1032 | type = packet_read_poll_seqnr(seqnr_p); | |
1033 | if (!compat20 && ( | |
1034 | type == SSH_SMSG_SUCCESS | |
1035 | || type == SSH_SMSG_FAILURE | |
1036 | || type == SSH_CMSG_EOF | |
1037 | || type == SSH_CMSG_EXIT_CONFIRMATION)) | |
1038 | packet_check_eom(); | |
1039 | /* If we got a packet, return it. */ | |
1040 | if (type != SSH_MSG_NONE) { | |
1041 | xfree(setp); | |
1042 | return type; | |
1043 | } | |
1044 | /* | |
1045 | * Otherwise, wait for some data to arrive, add it to the | |
1046 | * buffer, and try again. | |
1047 | */ | |
1048 | memset(setp, 0, howmany(active_state->connection_in + 1, | |
1049 | NFDBITS) * sizeof(fd_mask)); | |
1050 | FD_SET(active_state->connection_in, setp); | |
1051 | ||
1052 | if (active_state->packet_timeout_ms > 0) { | |
1053 | ms_remain = active_state->packet_timeout_ms; | |
1054 | timeoutp = &timeout; | |
1055 | } | |
1056 | /* Wait for some data to arrive. */ | |
1057 | for (;;) { | |
1058 | if (active_state->packet_timeout_ms != -1) { | |
1059 | ms_to_timeval(&timeout, ms_remain); | |
1060 | gettimeofday(&start, NULL); | |
1061 | } | |
1062 | if ((ret = select(active_state->connection_in + 1, setp, | |
1063 | NULL, NULL, timeoutp)) >= 0) | |
1064 | break; | |
1065 | if (errno != EAGAIN && errno != EINTR) | |
1066 | break; | |
1067 | if (active_state->packet_timeout_ms == -1) | |
1068 | continue; | |
1069 | ms_subtract_diff(&start, &ms_remain); | |
1070 | if (ms_remain <= 0) { | |
1071 | ret = 0; | |
1072 | break; | |
1073 | } | |
1074 | } | |
1075 | if (ret == 0) { | |
1076 | logit("Connection to %.200s timed out while " | |
1077 | "waiting to read", get_remote_ipaddr()); | |
1078 | cleanup_exit(255); | |
1079 | } | |
1080 | /* Read data from the socket. */ | |
1081 | do { | |
1082 | cont = 0; | |
1083 | len = roaming_read(active_state->connection_in, buf, | |
1084 | sizeof(buf), &cont); | |
1085 | } while (len == 0 && cont); | |
1086 | if (len == 0) { | |
1087 | logit("Connection closed by %.200s", get_remote_ipaddr()); | |
1088 | cleanup_exit(255); | |
1089 | } | |
1090 | if (len < 0) | |
1091 | fatal("Read from socket failed: %.100s", strerror(errno)); | |
1092 | /* Append it to the buffer. */ | |
1093 | packet_process_incoming(buf, len); | |
1094 | } | |
1095 | /* NOTREACHED */ | |
1096 | } | |
1097 | ||
1098 | int | |
1099 | packet_read(void) | |
1100 | { | |
1101 | return packet_read_seqnr(NULL); | |
1102 | } | |
1103 | ||
1104 | /* | |
1105 | * Waits until a packet has been received, verifies that its type matches | |
1106 | * that given, and gives a fatal error and exits if there is a mismatch. | |
1107 | */ | |
1108 | ||
1109 | void | |
1110 | packet_read_expect(int expected_type) | |
1111 | { | |
1112 | int type; | |
1113 | ||
1114 | type = packet_read(); | |
1115 | if (type != expected_type) | |
1116 | packet_disconnect("Protocol error: expected packet type %d, got %d", | |
1117 | expected_type, type); | |
1118 | } | |
1119 | ||
1120 | /* Checks if a full packet is available in the data received so far via | |
1121 | * packet_process_incoming. If so, reads the packet; otherwise returns | |
1122 | * SSH_MSG_NONE. This does not wait for data from the connection. | |
1123 | * | |
1124 | * SSH_MSG_DISCONNECT is handled specially here. Also, | |
1125 | * SSH_MSG_IGNORE messages are skipped by this function and are never returned | |
1126 | * to higher levels. | |
1127 | */ | |
1128 | ||
1129 | static int | |
1130 | packet_read_poll1(void) | |
1131 | { | |
1132 | u_int len, padded_len; | |
1133 | u_char *cp, type; | |
1134 | u_int checksum, stored_checksum; | |
1135 | ||
1136 | /* Check if input size is less than minimum packet size. */ | |
1137 | if (buffer_len(&active_state->input) < 4 + 8) | |
1138 | return SSH_MSG_NONE; | |
1139 | /* Get length of incoming packet. */ | |
1140 | cp = buffer_ptr(&active_state->input); | |
1141 | len = get_u32(cp); | |
1142 | if (len < 1 + 2 + 2 || len > 256 * 1024) | |
1143 | packet_disconnect("Bad packet length %u.", len); | |
1144 | padded_len = (len + 8) & ~7; | |
1145 | ||
1146 | /* Check if the packet has been entirely received. */ | |
1147 | if (buffer_len(&active_state->input) < 4 + padded_len) | |
1148 | return SSH_MSG_NONE; | |
1149 | ||
1150 | /* The entire packet is in buffer. */ | |
1151 | ||
1152 | /* Consume packet length. */ | |
1153 | buffer_consume(&active_state->input, 4); | |
1154 | ||
1155 | /* | |
1156 | * Cryptographic attack detector for ssh | |
1157 | * (C)1998 CORE-SDI, Buenos Aires Argentina | |
1158 | * Ariel Futoransky(futo@core-sdi.com) | |
1159 | */ | |
1160 | if (!active_state->receive_context.plaintext) { | |
1161 | switch (detect_attack(buffer_ptr(&active_state->input), | |
1162 | padded_len)) { | |
1163 | case DEATTACK_DETECTED: | |
1164 | packet_disconnect("crc32 compensation attack: " | |
1165 | "network attack detected"); | |
1166 | case DEATTACK_DOS_DETECTED: | |
1167 | packet_disconnect("deattack denial of " | |
1168 | "service detected"); | |
1169 | } | |
1170 | } | |
1171 | ||
1172 | /* Decrypt data to incoming_packet. */ | |
1173 | buffer_clear(&active_state->incoming_packet); | |
1174 | cp = buffer_append_space(&active_state->incoming_packet, padded_len); | |
1175 | cipher_crypt(&active_state->receive_context, cp, | |
1176 | buffer_ptr(&active_state->input), padded_len); | |
1177 | ||
1178 | buffer_consume(&active_state->input, padded_len); | |
1179 | ||
1180 | #ifdef PACKET_DEBUG | |
1181 | fprintf(stderr, "read_poll plain: "); | |
1182 | buffer_dump(&active_state->incoming_packet); | |
1183 | #endif | |
1184 | ||
1185 | /* Compute packet checksum. */ | |
1186 | checksum = ssh_crc32(buffer_ptr(&active_state->incoming_packet), | |
1187 | buffer_len(&active_state->incoming_packet) - 4); | |
1188 | ||
1189 | /* Skip padding. */ | |
1190 | buffer_consume(&active_state->incoming_packet, 8 - len % 8); | |
1191 | ||
1192 | /* Test check bytes. */ | |
1193 | if (len != buffer_len(&active_state->incoming_packet)) | |
1194 | packet_disconnect("packet_read_poll1: len %d != buffer_len %d.", | |
1195 | len, buffer_len(&active_state->incoming_packet)); | |
1196 | ||
1197 | cp = (u_char *)buffer_ptr(&active_state->incoming_packet) + len - 4; | |
1198 | stored_checksum = get_u32(cp); | |
1199 | if (checksum != stored_checksum) | |
1200 | packet_disconnect("Corrupted check bytes on input."); | |
1201 | buffer_consume_end(&active_state->incoming_packet, 4); | |
1202 | ||
1203 | if (active_state->packet_compression) { | |
1204 | buffer_clear(&active_state->compression_buffer); | |
1205 | buffer_uncompress(&active_state->incoming_packet, | |
1206 | &active_state->compression_buffer); | |
1207 | buffer_clear(&active_state->incoming_packet); | |
1208 | buffer_append(&active_state->incoming_packet, | |
1209 | buffer_ptr(&active_state->compression_buffer), | |
1210 | buffer_len(&active_state->compression_buffer)); | |
1211 | } | |
1212 | active_state->p_read.packets++; | |
1213 | active_state->p_read.bytes += padded_len + 4; | |
1214 | type = buffer_get_char(&active_state->incoming_packet); | |
1215 | if (type < SSH_MSG_MIN || type > SSH_MSG_MAX) | |
1216 | packet_disconnect("Invalid ssh1 packet type: %d", type); | |
1217 | return type; | |
1218 | } | |
1219 | ||
1220 | static int | |
1221 | packet_read_poll2(u_int32_t *seqnr_p) | |
1222 | { | |
1223 | u_int padlen, need; | |
1224 | u_char *macbuf, *cp, type; | |
1225 | u_int maclen, block_size; | |
1226 | Enc *enc = NULL; | |
1227 | Mac *mac = NULL; | |
1228 | Comp *comp = NULL; | |
1229 | ||
1230 | if (active_state->packet_discard) | |
1231 | return SSH_MSG_NONE; | |
1232 | ||
1233 | if (active_state->newkeys[MODE_IN] != NULL) { | |
1234 | enc = &active_state->newkeys[MODE_IN]->enc; | |
1235 | mac = &active_state->newkeys[MODE_IN]->mac; | |
1236 | comp = &active_state->newkeys[MODE_IN]->comp; | |
1237 | } | |
1238 | maclen = mac && mac->enabled ? mac->mac_len : 0; | |
1239 | block_size = enc ? enc->block_size : 8; | |
1240 | ||
1241 | if (active_state->packlen == 0) { | |
1242 | /* | |
1243 | * check if input size is less than the cipher block size, | |
1244 | * decrypt first block and extract length of incoming packet | |
1245 | */ | |
1246 | if (buffer_len(&active_state->input) < block_size) | |
1247 | return SSH_MSG_NONE; | |
1248 | buffer_clear(&active_state->incoming_packet); | |
1249 | cp = buffer_append_space(&active_state->incoming_packet, | |
1250 | block_size); | |
1251 | cipher_crypt(&active_state->receive_context, cp, | |
1252 | buffer_ptr(&active_state->input), block_size); | |
1253 | cp = buffer_ptr(&active_state->incoming_packet); | |
1254 | active_state->packlen = get_u32(cp); | |
1255 | if (active_state->packlen < 1 + 4 || | |
1256 | active_state->packlen > PACKET_MAX_SIZE) { | |
1257 | #ifdef PACKET_DEBUG | |
1258 | buffer_dump(&active_state->incoming_packet); | |
1259 | #endif | |
1260 | logit("Bad packet length %u.", active_state->packlen); | |
1261 | packet_start_discard(enc, mac, active_state->packlen, | |
1262 | PACKET_MAX_SIZE); | |
1263 | return SSH_MSG_NONE; | |
1264 | } | |
1265 | DBG(debug("input: packet len %u", active_state->packlen+4)); | |
1266 | buffer_consume(&active_state->input, block_size); | |
1267 | } | |
1268 | /* we have a partial packet of block_size bytes */ | |
1269 | need = 4 + active_state->packlen - block_size; | |
1270 | DBG(debug("partial packet %d, need %d, maclen %d", block_size, | |
1271 | need, maclen)); | |
1272 | if (need % block_size != 0) { | |
1273 | logit("padding error: need %d block %d mod %d", | |
1274 | need, block_size, need % block_size); | |
1275 | packet_start_discard(enc, mac, active_state->packlen, | |
1276 | PACKET_MAX_SIZE - block_size); | |
1277 | return SSH_MSG_NONE; | |
1278 | } | |
1279 | /* | |
1280 | * check if the entire packet has been received and | |
1281 | * decrypt into incoming_packet | |
1282 | */ | |
1283 | if (buffer_len(&active_state->input) < need + maclen) | |
1284 | return SSH_MSG_NONE; | |
1285 | #ifdef PACKET_DEBUG | |
1286 | fprintf(stderr, "read_poll enc/full: "); | |
1287 | buffer_dump(&active_state->input); | |
1288 | #endif | |
1289 | cp = buffer_append_space(&active_state->incoming_packet, need); | |
1290 | cipher_crypt(&active_state->receive_context, cp, | |
1291 | buffer_ptr(&active_state->input), need); | |
1292 | buffer_consume(&active_state->input, need); | |
1293 | /* | |
1294 | * compute MAC over seqnr and packet, | |
1295 | * increment sequence number for incoming packet | |
1296 | */ | |
1297 | if (mac && mac->enabled) { | |
1298 | macbuf = mac_compute(mac, active_state->p_read.seqnr, | |
1299 | buffer_ptr(&active_state->incoming_packet), | |
1300 | buffer_len(&active_state->incoming_packet)); | |
1301 | if (memcmp(macbuf, buffer_ptr(&active_state->input), | |
1302 | mac->mac_len) != 0) { | |
1303 | logit("Corrupted MAC on input."); | |
1304 | if (need > PACKET_MAX_SIZE) | |
1305 | fatal("internal error need %d", need); | |
1306 | packet_start_discard(enc, mac, active_state->packlen, | |
1307 | PACKET_MAX_SIZE - need); | |
1308 | return SSH_MSG_NONE; | |
1309 | } | |
1310 | ||
1311 | DBG(debug("MAC #%d ok", active_state->p_read.seqnr)); | |
1312 | buffer_consume(&active_state->input, mac->mac_len); | |
1313 | } | |
1314 | /* XXX now it's safe to use fatal/packet_disconnect */ | |
1315 | if (seqnr_p != NULL) | |
1316 | *seqnr_p = active_state->p_read.seqnr; | |
1317 | if (++active_state->p_read.seqnr == 0) | |
1318 | logit("incoming seqnr wraps around"); | |
1319 | if (++active_state->p_read.packets == 0) | |
1320 | if (!(datafellows & SSH_BUG_NOREKEY)) | |
1321 | fatal("XXX too many packets with same key"); | |
1322 | active_state->p_read.blocks += (active_state->packlen + 4) / block_size; | |
1323 | active_state->p_read.bytes += active_state->packlen + 4; | |
1324 | ||
1325 | /* get padlen */ | |
1326 | cp = buffer_ptr(&active_state->incoming_packet); | |
1327 | padlen = cp[4]; | |
1328 | DBG(debug("input: padlen %d", padlen)); | |
1329 | if (padlen < 4) | |
1330 | packet_disconnect("Corrupted padlen %d on input.", padlen); | |
1331 | ||
1332 | /* skip packet size + padlen, discard padding */ | |
1333 | buffer_consume(&active_state->incoming_packet, 4 + 1); | |
1334 | buffer_consume_end(&active_state->incoming_packet, padlen); | |
1335 | ||
1336 | DBG(debug("input: len before de-compress %d", | |
1337 | buffer_len(&active_state->incoming_packet))); | |
1338 | if (comp && comp->enabled) { | |
1339 | buffer_clear(&active_state->compression_buffer); | |
1340 | buffer_uncompress(&active_state->incoming_packet, | |
1341 | &active_state->compression_buffer); | |
1342 | buffer_clear(&active_state->incoming_packet); | |
1343 | buffer_append(&active_state->incoming_packet, | |
1344 | buffer_ptr(&active_state->compression_buffer), | |
1345 | buffer_len(&active_state->compression_buffer)); | |
1346 | DBG(debug("input: len after de-compress %d", | |
1347 | buffer_len(&active_state->incoming_packet))); | |
1348 | } | |
1349 | /* | |
1350 | * get packet type, implies consume. | |
1351 | * return length of payload (without type field) | |
1352 | */ | |
1353 | type = buffer_get_char(&active_state->incoming_packet); | |
1354 | if (type < SSH2_MSG_MIN || type >= SSH2_MSG_LOCAL_MIN) | |
1355 | packet_disconnect("Invalid ssh2 packet type: %d", type); | |
1356 | if (type == SSH2_MSG_NEWKEYS) | |
1357 | set_newkeys(MODE_IN); | |
1358 | else if (type == SSH2_MSG_USERAUTH_SUCCESS && | |
1359 | !active_state->server_side) | |
1360 | packet_enable_delayed_compress(); | |
1361 | #ifdef PACKET_DEBUG | |
1362 | fprintf(stderr, "read/plain[%d]:\r\n", type); | |
1363 | buffer_dump(&active_state->incoming_packet); | |
1364 | #endif | |
1365 | /* reset for next packet */ | |
1366 | active_state->packlen = 0; | |
1367 | return type; | |
1368 | } | |
1369 | ||
1370 | int | |
1371 | packet_read_poll_seqnr(u_int32_t *seqnr_p) | |
1372 | { | |
1373 | u_int reason, seqnr; | |
1374 | u_char type; | |
1375 | char *msg; | |
1376 | ||
1377 | for (;;) { | |
1378 | if (compat20) { | |
1379 | type = packet_read_poll2(seqnr_p); | |
1380 | if (type) { | |
1381 | active_state->keep_alive_timeouts = 0; | |
1382 | DBG(debug("received packet type %d", type)); | |
1383 | } | |
1384 | switch (type) { | |
1385 | case SSH2_MSG_IGNORE: | |
1386 | debug3("Received SSH2_MSG_IGNORE"); | |
1387 | break; | |
1388 | case SSH2_MSG_DEBUG: | |
1389 | packet_get_char(); | |
1390 | msg = packet_get_string(NULL); | |
1391 | debug("Remote: %.900s", msg); | |
1392 | xfree(msg); | |
1393 | msg = packet_get_string(NULL); | |
1394 | xfree(msg); | |
1395 | break; | |
1396 | case SSH2_MSG_DISCONNECT: | |
1397 | reason = packet_get_int(); | |
1398 | msg = packet_get_string(NULL); | |
1399 | logit("Received disconnect from %s: %u: %.400s", | |
1400 | get_remote_ipaddr(), reason, msg); | |
1401 | xfree(msg); | |
1402 | cleanup_exit(255); | |
1403 | break; | |
1404 | case SSH2_MSG_UNIMPLEMENTED: | |
1405 | seqnr = packet_get_int(); | |
1406 | debug("Received SSH2_MSG_UNIMPLEMENTED for %u", | |
1407 | seqnr); | |
1408 | break; | |
1409 | default: | |
1410 | return type; | |
1411 | } | |
1412 | } else { | |
1413 | type = packet_read_poll1(); | |
1414 | switch (type) { | |
1415 | case SSH_MSG_IGNORE: | |
1416 | break; | |
1417 | case SSH_MSG_DEBUG: | |
1418 | msg = packet_get_string(NULL); | |
1419 | debug("Remote: %.900s", msg); | |
1420 | xfree(msg); | |
1421 | break; | |
1422 | case SSH_MSG_DISCONNECT: | |
1423 | msg = packet_get_string(NULL); | |
1424 | logit("Received disconnect from %s: %.400s", | |
1425 | get_remote_ipaddr(), msg); | |
1426 | cleanup_exit(255); | |
1427 | break; | |
1428 | default: | |
1429 | if (type) | |
1430 | DBG(debug("received packet type %d", type)); | |
1431 | return type; | |
1432 | } | |
1433 | } | |
1434 | } | |
1435 | } | |
1436 | ||
1437 | int | |
1438 | packet_read_poll(void) | |
1439 | { | |
1440 | return packet_read_poll_seqnr(NULL); | |
1441 | } | |
1442 | ||
1443 | /* | |
1444 | * Buffers the given amount of input characters. This is intended to be used | |
1445 | * together with packet_read_poll. | |
1446 | */ | |
1447 | ||
1448 | void | |
1449 | packet_process_incoming(const char *buf, u_int len) | |
1450 | { | |
1451 | if (active_state->packet_discard) { | |
1452 | active_state->keep_alive_timeouts = 0; /* ?? */ | |
1453 | if (len >= active_state->packet_discard) | |
1454 | packet_stop_discard(); | |
1455 | active_state->packet_discard -= len; | |
1456 | return; | |
1457 | } | |
1458 | buffer_append(&active_state->input, buf, len); | |
1459 | } | |
1460 | ||
1461 | /* Returns a character from the packet. */ | |
1462 | ||
1463 | u_int | |
1464 | packet_get_char(void) | |
1465 | { | |
1466 | char ch; | |
1467 | ||
1468 | buffer_get(&active_state->incoming_packet, &ch, 1); | |
1469 | return (u_char) ch; | |
1470 | } | |
1471 | ||
1472 | /* Returns an integer from the packet data. */ | |
1473 | ||
1474 | u_int | |
1475 | packet_get_int(void) | |
1476 | { | |
1477 | return buffer_get_int(&active_state->incoming_packet); | |
1478 | } | |
1479 | ||
1480 | /* Returns an 64 bit integer from the packet data. */ | |
1481 | ||
1482 | u_int64_t | |
1483 | packet_get_int64(void) | |
1484 | { | |
1485 | return buffer_get_int64(&active_state->incoming_packet); | |
1486 | } | |
1487 | ||
1488 | /* | |
1489 | * Returns an arbitrary precision integer from the packet data. The integer | |
1490 | * must have been initialized before this call. | |
1491 | */ | |
1492 | ||
1493 | void | |
1494 | packet_get_bignum(BIGNUM * value) | |
1495 | { | |
1496 | buffer_get_bignum(&active_state->incoming_packet, value); | |
1497 | } | |
1498 | ||
1499 | void | |
1500 | packet_get_bignum2(BIGNUM * value) | |
1501 | { | |
1502 | buffer_get_bignum2(&active_state->incoming_packet, value); | |
1503 | } | |
1504 | ||
1505 | void * | |
1506 | packet_get_raw(u_int *length_ptr) | |
1507 | { | |
1508 | u_int bytes = buffer_len(&active_state->incoming_packet); | |
1509 | ||
1510 | if (length_ptr != NULL) | |
1511 | *length_ptr = bytes; | |
1512 | return buffer_ptr(&active_state->incoming_packet); | |
1513 | } | |
1514 | ||
1515 | int | |
1516 | packet_remaining(void) | |
1517 | { | |
1518 | return buffer_len(&active_state->incoming_packet); | |
1519 | } | |
1520 | ||
1521 | /* | |
1522 | * Returns a string from the packet data. The string is allocated using | |
1523 | * xmalloc; it is the responsibility of the calling program to free it when | |
1524 | * no longer needed. The length_ptr argument may be NULL, or point to an | |
1525 | * integer into which the length of the string is stored. | |
1526 | */ | |
1527 | ||
1528 | void * | |
1529 | packet_get_string(u_int *length_ptr) | |
1530 | { | |
1531 | return buffer_get_string(&active_state->incoming_packet, length_ptr); | |
1532 | } | |
1533 | ||
1534 | void * | |
1535 | packet_get_string_ptr(u_int *length_ptr) | |
1536 | { | |
1537 | return buffer_get_string_ptr(&active_state->incoming_packet, length_ptr); | |
1538 | } | |
1539 | ||
1540 | /* | |
1541 | * Sends a diagnostic message from the server to the client. This message | |
1542 | * can be sent at any time (but not while constructing another message). The | |
1543 | * message is printed immediately, but only if the client is being executed | |
1544 | * in verbose mode. These messages are primarily intended to ease debugging | |
1545 | * authentication problems. The length of the formatted message must not | |
1546 | * exceed 1024 bytes. This will automatically call packet_write_wait. | |
1547 | */ | |
1548 | ||
1549 | void | |
1550 | packet_send_debug(const char *fmt,...) | |
1551 | { | |
1552 | char buf[1024]; | |
1553 | va_list args; | |
1554 | ||
1555 | if (compat20 && (datafellows & SSH_BUG_DEBUG)) | |
1556 | return; | |
1557 | ||
1558 | va_start(args, fmt); | |
1559 | vsnprintf(buf, sizeof(buf), fmt, args); | |
1560 | va_end(args); | |
1561 | ||
1562 | if (compat20) { | |
1563 | packet_start(SSH2_MSG_DEBUG); | |
1564 | packet_put_char(0); /* bool: always display */ | |
1565 | packet_put_cstring(buf); | |
1566 | packet_put_cstring(""); | |
1567 | } else { | |
1568 | packet_start(SSH_MSG_DEBUG); | |
1569 | packet_put_cstring(buf); | |
1570 | } | |
1571 | packet_send(); | |
1572 | packet_write_wait(); | |
1573 | } | |
1574 | ||
1575 | /* | |
1576 | * Logs the error plus constructs and sends a disconnect packet, closes the | |
1577 | * connection, and exits. This function never returns. The error message | |
1578 | * should not contain a newline. The length of the formatted message must | |
1579 | * not exceed 1024 bytes. | |
1580 | */ | |
1581 | ||
1582 | void | |
1583 | packet_disconnect(const char *fmt,...) | |
1584 | { | |
1585 | char buf[1024]; | |
1586 | va_list args; | |
1587 | static int disconnecting = 0; | |
1588 | ||
1589 | if (disconnecting) /* Guard against recursive invocations. */ | |
1590 | fatal("packet_disconnect called recursively."); | |
1591 | disconnecting = 1; | |
1592 | ||
1593 | /* | |
1594 | * Format the message. Note that the caller must make sure the | |
1595 | * message is of limited size. | |
1596 | */ | |
1597 | va_start(args, fmt); | |
1598 | vsnprintf(buf, sizeof(buf), fmt, args); | |
1599 | va_end(args); | |
1600 | ||
1601 | /* Display the error locally */ | |
1602 | logit("Disconnecting: %.100s", buf); | |
1603 | ||
1604 | /* Send the disconnect message to the other side, and wait for it to get sent. */ | |
1605 | if (compat20) { | |
1606 | packet_start(SSH2_MSG_DISCONNECT); | |
1607 | packet_put_int(SSH2_DISCONNECT_PROTOCOL_ERROR); | |
1608 | packet_put_cstring(buf); | |
1609 | packet_put_cstring(""); | |
1610 | } else { | |
1611 | packet_start(SSH_MSG_DISCONNECT); | |
1612 | packet_put_cstring(buf); | |
1613 | } | |
1614 | packet_send(); | |
1615 | packet_write_wait(); | |
1616 | ||
1617 | /* Stop listening for connections. */ | |
1618 | channel_close_all(); | |
1619 | ||
1620 | /* Close the connection. */ | |
1621 | packet_close(); | |
1622 | cleanup_exit(255); | |
1623 | } | |
1624 | ||
1625 | /* Checks if there is any buffered output, and tries to write some of the output. */ | |
1626 | ||
1627 | void | |
1628 | packet_write_poll(void) | |
1629 | { | |
1630 | int len = buffer_len(&active_state->output); | |
1631 | int cont; | |
1632 | ||
1633 | if (len > 0) { | |
1634 | cont = 0; | |
1635 | len = roaming_write(active_state->connection_out, | |
1636 | buffer_ptr(&active_state->output), len, &cont); | |
1637 | if (len == -1) { | |
1638 | if (errno == EINTR || errno == EAGAIN) | |
1639 | return; | |
1640 | fatal("Write failed: %.100s", strerror(errno)); | |
1641 | } | |
1642 | if (len == 0 && !cont) | |
1643 | fatal("Write connection closed"); | |
1644 | buffer_consume(&active_state->output, len); | |
1645 | } | |
1646 | } | |
1647 | ||
1648 | /* | |
1649 | * Calls packet_write_poll repeatedly until all pending output data has been | |
1650 | * written. | |
1651 | */ | |
1652 | ||
1653 | void | |
1654 | packet_write_wait(void) | |
1655 | { | |
1656 | fd_set *setp; | |
1657 | int ret, ms_remain; | |
1658 | struct timeval start, timeout, *timeoutp = NULL; | |
1659 | ||
1660 | setp = (fd_set *)xcalloc(howmany(active_state->connection_out + 1, | |
1661 | NFDBITS), sizeof(fd_mask)); | |
1662 | packet_write_poll(); | |
1663 | while (packet_have_data_to_write()) { | |
1664 | memset(setp, 0, howmany(active_state->connection_out + 1, | |
1665 | NFDBITS) * sizeof(fd_mask)); | |
1666 | FD_SET(active_state->connection_out, setp); | |
1667 | ||
1668 | if (active_state->packet_timeout_ms > 0) { | |
1669 | ms_remain = active_state->packet_timeout_ms; | |
1670 | timeoutp = &timeout; | |
1671 | } | |
1672 | for (;;) { | |
1673 | if (active_state->packet_timeout_ms != -1) { | |
1674 | ms_to_timeval(&timeout, ms_remain); | |
1675 | gettimeofday(&start, NULL); | |
1676 | } | |
1677 | if ((ret = select(active_state->connection_out + 1, | |
1678 | NULL, setp, NULL, timeoutp)) >= 0) | |
1679 | break; | |
1680 | if (errno != EAGAIN && errno != EINTR) | |
1681 | break; | |
1682 | if (active_state->packet_timeout_ms == -1) | |
1683 | continue; | |
1684 | ms_subtract_diff(&start, &ms_remain); | |
1685 | if (ms_remain <= 0) { | |
1686 | ret = 0; | |
1687 | break; | |
1688 | } | |
1689 | } | |
1690 | if (ret == 0) { | |
1691 | logit("Connection to %.200s timed out while " | |
1692 | "waiting to write", get_remote_ipaddr()); | |
1693 | cleanup_exit(255); | |
1694 | } | |
1695 | packet_write_poll(); | |
1696 | } | |
1697 | xfree(setp); | |
1698 | } | |
1699 | ||
1700 | /* Returns true if there is buffered data to write to the connection. */ | |
1701 | ||
1702 | int | |
1703 | packet_have_data_to_write(void) | |
1704 | { | |
1705 | return buffer_len(&active_state->output) != 0; | |
1706 | } | |
1707 | ||
1708 | /* Returns true if there is not too much data to write to the connection. */ | |
1709 | ||
1710 | int | |
1711 | packet_not_very_much_data_to_write(void) | |
1712 | { | |
1713 | if (active_state->interactive_mode) | |
1714 | return buffer_len(&active_state->output) < 16384; | |
1715 | else | |
1716 | return buffer_len(&active_state->output) < 128 * 1024; | |
1717 | } | |
1718 | ||
1719 | static void | |
1720 | packet_set_tos(int interactive) | |
1721 | { | |
1722 | #if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN) | |
1723 | int tos = interactive ? IPTOS_LOWDELAY : IPTOS_THROUGHPUT; | |
1724 | ||
1725 | if (!packet_connection_is_on_socket() || | |
1726 | !packet_connection_is_ipv4()) | |
1727 | return; | |
1728 | if (setsockopt(active_state->connection_in, IPPROTO_IP, IP_TOS, &tos, | |
1729 | sizeof(tos)) < 0) | |
1730 | error("setsockopt IP_TOS %d: %.100s:", | |
1731 | tos, strerror(errno)); | |
1732 | #endif | |
1733 | } | |
1734 | ||
1735 | /* Informs that the current session is interactive. Sets IP flags for that. */ | |
1736 | ||
1737 | void | |
1738 | packet_set_interactive(int interactive) | |
1739 | { | |
1740 | static int called = 0; | |
1741 | ||
1742 | if (called) | |
1743 | return; | |
1744 | called = 1; | |
1745 | ||
1746 | /* Record that we are in interactive mode. */ | |
1747 | active_state->interactive_mode = interactive; | |
1748 | ||
1749 | /* Only set socket options if using a socket. */ | |
1750 | if (!packet_connection_is_on_socket()) | |
1751 | return; | |
1752 | set_nodelay(active_state->connection_in); | |
1753 | packet_set_tos(interactive); | |
1754 | } | |
1755 | ||
1756 | /* Returns true if the current connection is interactive. */ | |
1757 | ||
1758 | int | |
1759 | packet_is_interactive(void) | |
1760 | { | |
1761 | return active_state->interactive_mode; | |
1762 | } | |
1763 | ||
1764 | int | |
1765 | packet_set_maxsize(u_int s) | |
1766 | { | |
1767 | static int called = 0; | |
1768 | ||
1769 | if (called) { | |
1770 | logit("packet_set_maxsize: called twice: old %d new %d", | |
1771 | active_state->max_packet_size, s); | |
1772 | return -1; | |
1773 | } | |
1774 | if (s < 4 * 1024 || s > 1024 * 1024) { | |
1775 | logit("packet_set_maxsize: bad size %d", s); | |
1776 | return -1; | |
1777 | } | |
1778 | called = 1; | |
1779 | debug("packet_set_maxsize: setting to %d", s); | |
1780 | active_state->max_packet_size = s; | |
1781 | return s; | |
1782 | } | |
1783 | ||
1784 | int | |
1785 | packet_inc_alive_timeouts(void) | |
1786 | { | |
1787 | return ++active_state->keep_alive_timeouts; | |
1788 | } | |
1789 | ||
1790 | void | |
1791 | packet_set_alive_timeouts(int ka) | |
1792 | { | |
1793 | active_state->keep_alive_timeouts = ka; | |
1794 | } | |
1795 | ||
1796 | u_int | |
1797 | packet_get_maxsize(void) | |
1798 | { | |
1799 | return active_state->max_packet_size; | |
1800 | } | |
1801 | ||
1802 | /* roundup current message to pad bytes */ | |
1803 | void | |
1804 | packet_add_padding(u_char pad) | |
1805 | { | |
1806 | active_state->extra_pad = pad; | |
1807 | } | |
1808 | ||
1809 | /* | |
1810 | * 9.2. Ignored Data Message | |
1811 | * | |
1812 | * byte SSH_MSG_IGNORE | |
1813 | * string data | |
1814 | * | |
1815 | * All implementations MUST understand (and ignore) this message at any | |
1816 | * time (after receiving the protocol version). No implementation is | |
1817 | * required to send them. This message can be used as an additional | |
1818 | * protection measure against advanced traffic analysis techniques. | |
1819 | */ | |
1820 | void | |
1821 | packet_send_ignore(int nbytes) | |
1822 | { | |
1823 | u_int32_t rnd = 0; | |
1824 | int i; | |
1825 | ||
1826 | packet_start(compat20 ? SSH2_MSG_IGNORE : SSH_MSG_IGNORE); | |
1827 | packet_put_int(nbytes); | |
1828 | for (i = 0; i < nbytes; i++) { | |
1829 | if (i % 4 == 0) | |
1830 | rnd = arc4random(); | |
1831 | packet_put_char((u_char)rnd & 0xff); | |
1832 | rnd >>= 8; | |
1833 | } | |
1834 | } | |
1835 | ||
1836 | #define MAX_PACKETS (1U<<31) | |
1837 | int | |
1838 | packet_need_rekeying(void) | |
1839 | { | |
1840 | if (datafellows & SSH_BUG_NOREKEY) | |
1841 | return 0; | |
1842 | return | |
1843 | (active_state->p_send.packets > MAX_PACKETS) || | |
1844 | (active_state->p_read.packets > MAX_PACKETS) || | |
1845 | (active_state->max_blocks_out && | |
1846 | (active_state->p_send.blocks > active_state->max_blocks_out)) || | |
1847 | (active_state->max_blocks_in && | |
1848 | (active_state->p_read.blocks > active_state->max_blocks_in)); | |
1849 | } | |
1850 | ||
1851 | void | |
1852 | packet_set_rekey_limit(u_int32_t bytes) | |
1853 | { | |
1854 | active_state->rekey_limit = bytes; | |
1855 | } | |
1856 | ||
1857 | void | |
1858 | packet_set_server(void) | |
1859 | { | |
1860 | active_state->server_side = 1; | |
1861 | } | |
1862 | ||
1863 | void | |
1864 | packet_set_authenticated(void) | |
1865 | { | |
1866 | active_state->after_authentication = 1; | |
1867 | } | |
1868 | ||
1869 | void * | |
1870 | packet_get_input(void) | |
1871 | { | |
1872 | return (void *)&active_state->input; | |
1873 | } | |
1874 | ||
1875 | void * | |
1876 | packet_get_output(void) | |
1877 | { | |
1878 | return (void *)&active_state->output; | |
1879 | } | |
1880 | ||
1881 | void * | |
1882 | packet_get_newkeys(int mode) | |
1883 | { | |
1884 | return (void *)active_state->newkeys[mode]; | |
1885 | } |