]>
Commit | Line | Data |
---|---|---|
3c0ef626 | 1 | /* |
2 | * Author: Tatu Ylonen <ylo@cs.hut.fi> | |
3 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland | |
4 | * All rights reserved | |
5 | * This file contains code implementing the packet protocol and communication | |
6 | * with the other side. This same code is used both on client and server side. | |
7 | * | |
8 | * As far as I am concerned, the code I have written for this software | |
9 | * can be used freely for any purpose. Any derived versions of this | |
10 | * software must be clearly marked as such, and if the derived work is | |
11 | * incompatible with the protocol description in the RFC file, it must be | |
12 | * called by a name other than "ssh" or "Secure Shell". | |
13 | * | |
14 | * | |
15 | * SSH2 packet format added by Markus Friedl. | |
16 | * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. | |
17 | * | |
18 | * Redistribution and use in source and binary forms, with or without | |
19 | * modification, are permitted provided that the following conditions | |
20 | * are met: | |
21 | * 1. Redistributions of source code must retain the above copyright | |
22 | * notice, this list of conditions and the following disclaimer. | |
23 | * 2. Redistributions in binary form must reproduce the above copyright | |
24 | * notice, this list of conditions and the following disclaimer in the | |
25 | * documentation and/or other materials provided with the distribution. | |
26 | * | |
27 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR | |
28 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES | |
29 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. | |
30 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, | |
31 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
32 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
33 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
34 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
35 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | |
36 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
37 | */ | |
38 | ||
39 | #include "includes.h" | |
7e82606e | 40 | RCSID("$OpenBSD: packet.c,v 1.115 2004/06/21 17:36:31 avsm Exp $"); |
7cac2b65 | 41 | |
42 | #include "openbsd-compat/sys-queue.h" | |
3c0ef626 | 43 | |
44 | #include "xmalloc.h" | |
45 | #include "buffer.h" | |
46 | #include "packet.h" | |
47 | #include "bufaux.h" | |
48 | #include "crc32.h" | |
49 | #include "getput.h" | |
50 | ||
51 | #include "compress.h" | |
52 | #include "deattack.h" | |
53 | #include "channels.h" | |
54 | ||
55 | #include "compat.h" | |
56 | #include "ssh1.h" | |
57 | #include "ssh2.h" | |
58 | ||
59 | #include "cipher.h" | |
60 | #include "kex.h" | |
61 | #include "mac.h" | |
62 | #include "log.h" | |
63 | #include "canohost.h" | |
1e608e42 | 64 | #include "misc.h" |
44a053a3 | 65 | #include "ssh.h" |
3c0ef626 | 66 | |
67 | #ifdef PACKET_DEBUG | |
68 | #define DBG(x) x | |
69 | #else | |
70 | #define DBG(x) | |
71 | #endif | |
72 | ||
73 | /* | |
74 | * This variable contains the file descriptors used for communicating with | |
75 | * the other side. connection_in is used for reading; connection_out for | |
76 | * writing. These can be the same descriptor, in which case it is assumed to | |
77 | * be a socket. | |
78 | */ | |
79 | static int connection_in = -1; | |
80 | static int connection_out = -1; | |
81 | ||
82 | /* Protocol flags for the remote side. */ | |
83 | static u_int remote_protocol_flags = 0; | |
84 | ||
85 | /* Encryption context for receiving data. This is only used for decryption. */ | |
86 | static CipherContext receive_context; | |
87 | ||
88 | /* Encryption context for sending data. This is only used for encryption. */ | |
89 | static CipherContext send_context; | |
90 | ||
91 | /* Buffer for raw input data from the socket. */ | |
510132b6 | 92 | Buffer input; |
3c0ef626 | 93 | |
94 | /* Buffer for raw output data going to the socket. */ | |
510132b6 | 95 | Buffer output; |
3c0ef626 | 96 | |
97 | /* Buffer for the partial outgoing packet being constructed. */ | |
98 | static Buffer outgoing_packet; | |
99 | ||
100 | /* Buffer for the incoming packet currently being processed. */ | |
101 | static Buffer incoming_packet; | |
102 | ||
103 | /* Scratch buffer for packet compression/decompression. */ | |
104 | static Buffer compression_buffer; | |
105 | static int compression_buffer_ready = 0; | |
106 | ||
107 | /* Flag indicating whether packet compression/decompression is enabled. */ | |
108 | static int packet_compression = 0; | |
109 | ||
110 | /* default maximum packet size */ | |
7cac2b65 | 111 | u_int max_packet_size = 32768; |
3c0ef626 | 112 | |
113 | /* Flag indicating whether this module has been initialized. */ | |
114 | static int initialized = 0; | |
115 | ||
116 | /* Set to true if the connection is interactive. */ | |
117 | static int interactive_mode = 0; | |
118 | ||
119 | /* Session key information for Encryption and MAC */ | |
120 | Newkeys *newkeys[MODE_MAX]; | |
7cac2b65 | 121 | static struct packet_state { |
122 | u_int32_t seqnr; | |
123 | u_int32_t packets; | |
124 | u_int64_t blocks; | |
125 | } p_read, p_send; | |
126 | ||
127 | static u_int64_t max_blocks_in, max_blocks_out; | |
128 | static u_int32_t rekey_limit; | |
3c0ef626 | 129 | |
44a053a3 | 130 | /* Session key for protocol v1 */ |
131 | static u_char ssh1_key[SSH_SESSION_KEY_LENGTH]; | |
132 | static u_int ssh1_keylen; | |
133 | ||
3c0ef626 | 134 | /* roundup current message to extra_pad bytes */ |
135 | static u_char extra_pad = 0; | |
136 | ||
7cac2b65 | 137 | struct packet { |
138 | TAILQ_ENTRY(packet) next; | |
139 | u_char type; | |
140 | Buffer payload; | |
141 | }; | |
142 | TAILQ_HEAD(, packet) outgoing; | |
143 | ||
3c0ef626 | 144 | /* |
145 | * Sets the descriptors used for communication. Disables encryption until | |
146 | * packet_set_encryption_key is called. | |
147 | */ | |
148 | void | |
149 | packet_set_connection(int fd_in, int fd_out) | |
150 | { | |
151 | Cipher *none = cipher_by_name("none"); | |
d03f4262 | 152 | |
3c0ef626 | 153 | if (none == NULL) |
154 | fatal("packet_set_connection: cannot load cipher 'none'"); | |
155 | connection_in = fd_in; | |
156 | connection_out = fd_out; | |
7e82606e | 157 | cipher_init(&send_context, none, (const u_char *)"", |
158 | 0, NULL, 0, CIPHER_ENCRYPT); | |
159 | cipher_init(&receive_context, none, (const u_char *)"", | |
160 | 0, NULL, 0, CIPHER_DECRYPT); | |
3c0ef626 | 161 | newkeys[MODE_IN] = newkeys[MODE_OUT] = NULL; |
162 | if (!initialized) { | |
163 | initialized = 1; | |
164 | buffer_init(&input); | |
165 | buffer_init(&output); | |
166 | buffer_init(&outgoing_packet); | |
167 | buffer_init(&incoming_packet); | |
7cac2b65 | 168 | TAILQ_INIT(&outgoing); |
3c0ef626 | 169 | } |
3c0ef626 | 170 | } |
171 | ||
172 | /* Returns 1 if remote host is connected via socket, 0 if not. */ | |
173 | ||
174 | int | |
1e608e42 | 175 | packet_connection_is_on_socket(void) |
3c0ef626 | 176 | { |
177 | struct sockaddr_storage from, to; | |
178 | socklen_t fromlen, tolen; | |
179 | ||
180 | /* filedescriptors in and out are the same, so it's a socket */ | |
181 | if (connection_in == connection_out) | |
182 | return 1; | |
183 | fromlen = sizeof(from); | |
184 | memset(&from, 0, sizeof(from)); | |
185 | if (getpeername(connection_in, (struct sockaddr *)&from, &fromlen) < 0) | |
186 | return 0; | |
187 | tolen = sizeof(to); | |
188 | memset(&to, 0, sizeof(to)); | |
189 | if (getpeername(connection_out, (struct sockaddr *)&to, &tolen) < 0) | |
190 | return 0; | |
191 | if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0) | |
192 | return 0; | |
193 | if (from.ss_family != AF_INET && from.ss_family != AF_INET6) | |
194 | return 0; | |
195 | return 1; | |
196 | } | |
197 | ||
510132b6 | 198 | /* |
199 | * Exports an IV from the CipherContext required to export the key | |
200 | * state back from the unprivileged child to the privileged parent | |
201 | * process. | |
202 | */ | |
203 | ||
204 | void | |
205 | packet_get_keyiv(int mode, u_char *iv, u_int len) | |
206 | { | |
207 | CipherContext *cc; | |
208 | ||
209 | if (mode == MODE_OUT) | |
210 | cc = &send_context; | |
211 | else | |
212 | cc = &receive_context; | |
213 | ||
214 | cipher_get_keyiv(cc, iv, len); | |
215 | } | |
216 | ||
217 | int | |
218 | packet_get_keycontext(int mode, u_char *dat) | |
219 | { | |
220 | CipherContext *cc; | |
221 | ||
222 | if (mode == MODE_OUT) | |
223 | cc = &send_context; | |
224 | else | |
225 | cc = &receive_context; | |
226 | ||
227 | return (cipher_get_keycontext(cc, dat)); | |
228 | } | |
229 | ||
230 | void | |
231 | packet_set_keycontext(int mode, u_char *dat) | |
232 | { | |
233 | CipherContext *cc; | |
234 | ||
235 | if (mode == MODE_OUT) | |
236 | cc = &send_context; | |
237 | else | |
238 | cc = &receive_context; | |
239 | ||
240 | cipher_set_keycontext(cc, dat); | |
241 | } | |
242 | ||
243 | int | |
244 | packet_get_keyiv_len(int mode) | |
245 | { | |
246 | CipherContext *cc; | |
247 | ||
248 | if (mode == MODE_OUT) | |
249 | cc = &send_context; | |
250 | else | |
251 | cc = &receive_context; | |
252 | ||
253 | return (cipher_get_keyiv_len(cc)); | |
254 | } | |
255 | void | |
256 | packet_set_iv(int mode, u_char *dat) | |
257 | { | |
258 | CipherContext *cc; | |
259 | ||
260 | if (mode == MODE_OUT) | |
261 | cc = &send_context; | |
262 | else | |
263 | cc = &receive_context; | |
264 | ||
265 | cipher_set_keyiv(cc, dat); | |
266 | } | |
267 | int | |
7cac2b65 | 268 | packet_get_ssh1_cipher(void) |
510132b6 | 269 | { |
270 | return (cipher_get_number(receive_context.cipher)); | |
271 | } | |
272 | ||
7cac2b65 | 273 | void |
274 | packet_get_state(int mode, u_int32_t *seqnr, u_int64_t *blocks, u_int32_t *packets) | |
510132b6 | 275 | { |
7cac2b65 | 276 | struct packet_state *state; |
277 | ||
278 | state = (mode == MODE_IN) ? &p_read : &p_send; | |
279 | *seqnr = state->seqnr; | |
280 | *blocks = state->blocks; | |
281 | *packets = state->packets; | |
510132b6 | 282 | } |
283 | ||
284 | void | |
7cac2b65 | 285 | packet_set_state(int mode, u_int32_t seqnr, u_int64_t blocks, u_int32_t packets) |
510132b6 | 286 | { |
7cac2b65 | 287 | struct packet_state *state; |
288 | ||
289 | state = (mode == MODE_IN) ? &p_read : &p_send; | |
290 | state->seqnr = seqnr; | |
291 | state->blocks = blocks; | |
292 | state->packets = packets; | |
510132b6 | 293 | } |
294 | ||
3c0ef626 | 295 | /* returns 1 if connection is via ipv4 */ |
296 | ||
297 | int | |
1e608e42 | 298 | packet_connection_is_ipv4(void) |
3c0ef626 | 299 | { |
300 | struct sockaddr_storage to; | |
301 | socklen_t tolen = sizeof(to); | |
302 | ||
303 | memset(&to, 0, sizeof(to)); | |
304 | if (getsockname(connection_out, (struct sockaddr *)&to, &tolen) < 0) | |
305 | return 0; | |
510132b6 | 306 | if (to.ss_family == AF_INET) |
307 | return 1; | |
308 | #ifdef IPV4_IN_IPV6 | |
540d72c3 | 309 | if (to.ss_family == AF_INET6 && |
510132b6 | 310 | IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)&to)->sin6_addr)) |
311 | return 1; | |
312 | #endif | |
313 | return 0; | |
3c0ef626 | 314 | } |
315 | ||
316 | /* Sets the connection into non-blocking mode. */ | |
317 | ||
318 | void | |
1e608e42 | 319 | packet_set_nonblocking(void) |
3c0ef626 | 320 | { |
321 | /* Set the socket into non-blocking mode. */ | |
7e82606e | 322 | set_nonblock(connection_in); |
3c0ef626 | 323 | |
7e82606e | 324 | if (connection_out != connection_in) |
325 | set_nonblock(connection_out); | |
3c0ef626 | 326 | } |
327 | ||
328 | /* Returns the socket used for reading. */ | |
329 | ||
330 | int | |
1e608e42 | 331 | packet_get_connection_in(void) |
3c0ef626 | 332 | { |
333 | return connection_in; | |
334 | } | |
335 | ||
336 | /* Returns the descriptor used for writing. */ | |
337 | ||
338 | int | |
1e608e42 | 339 | packet_get_connection_out(void) |
3c0ef626 | 340 | { |
341 | return connection_out; | |
342 | } | |
343 | ||
344 | /* Closes the connection and clears and frees internal data structures. */ | |
345 | ||
346 | void | |
1e608e42 | 347 | packet_close(void) |
3c0ef626 | 348 | { |
349 | if (!initialized) | |
350 | return; | |
351 | initialized = 0; | |
352 | if (connection_in == connection_out) { | |
353 | shutdown(connection_out, SHUT_RDWR); | |
354 | close(connection_out); | |
355 | } else { | |
356 | close(connection_in); | |
357 | close(connection_out); | |
358 | } | |
359 | buffer_free(&input); | |
360 | buffer_free(&output); | |
361 | buffer_free(&outgoing_packet); | |
362 | buffer_free(&incoming_packet); | |
363 | if (compression_buffer_ready) { | |
364 | buffer_free(&compression_buffer); | |
365 | buffer_compress_uninit(); | |
366 | } | |
1e608e42 | 367 | cipher_cleanup(&send_context); |
368 | cipher_cleanup(&receive_context); | |
3c0ef626 | 369 | } |
370 | ||
371 | /* Sets remote side protocol flags. */ | |
372 | ||
373 | void | |
374 | packet_set_protocol_flags(u_int protocol_flags) | |
375 | { | |
376 | remote_protocol_flags = protocol_flags; | |
377 | } | |
378 | ||
379 | /* Returns the remote protocol flags set earlier by the above function. */ | |
380 | ||
381 | u_int | |
1e608e42 | 382 | packet_get_protocol_flags(void) |
3c0ef626 | 383 | { |
384 | return remote_protocol_flags; | |
385 | } | |
386 | ||
387 | /* | |
388 | * Starts packet compression from the next packet on in both directions. | |
389 | * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip. | |
390 | */ | |
391 | ||
392 | static void | |
393 | packet_init_compression(void) | |
394 | { | |
395 | if (compression_buffer_ready == 1) | |
396 | return; | |
397 | compression_buffer_ready = 1; | |
398 | buffer_init(&compression_buffer); | |
399 | } | |
400 | ||
401 | void | |
402 | packet_start_compression(int level) | |
403 | { | |
404 | if (packet_compression && !compat20) | |
405 | fatal("Compression already enabled."); | |
406 | packet_compression = 1; | |
407 | packet_init_compression(); | |
408 | buffer_compress_init_send(level); | |
409 | buffer_compress_init_recv(); | |
410 | } | |
411 | ||
412 | /* | |
413 | * Causes any further packets to be encrypted using the given key. The same | |
414 | * key is used for both sending and reception. However, both directions are | |
415 | * encrypted independently of each other. | |
416 | */ | |
44a053a3 | 417 | |
3c0ef626 | 418 | void |
419 | packet_set_encryption_key(const u_char *key, u_int keylen, | |
420 | int number) | |
421 | { | |
422 | Cipher *cipher = cipher_by_number(number); | |
d03f4262 | 423 | |
3c0ef626 | 424 | if (cipher == NULL) |
425 | fatal("packet_set_encryption_key: unknown cipher number %d", number); | |
426 | if (keylen < 20) | |
427 | fatal("packet_set_encryption_key: keylen too small: %d", keylen); | |
44a053a3 | 428 | if (keylen > SSH_SESSION_KEY_LENGTH) |
429 | fatal("packet_set_encryption_key: keylen too big: %d", keylen); | |
430 | memcpy(ssh1_key, key, keylen); | |
431 | ssh1_keylen = keylen; | |
1e608e42 | 432 | cipher_init(&send_context, cipher, key, keylen, NULL, 0, CIPHER_ENCRYPT); |
433 | cipher_init(&receive_context, cipher, key, keylen, NULL, 0, CIPHER_DECRYPT); | |
3c0ef626 | 434 | } |
435 | ||
44a053a3 | 436 | u_int |
437 | packet_get_encryption_key(u_char *key) | |
438 | { | |
439 | if (key == NULL) | |
440 | return (ssh1_keylen); | |
441 | memcpy(key, ssh1_key, ssh1_keylen); | |
442 | return (ssh1_keylen); | |
443 | } | |
444 | ||
3c0ef626 | 445 | /* Start constructing a packet to send. */ |
446 | void | |
447 | packet_start(u_char type) | |
448 | { | |
449 | u_char buf[9]; | |
450 | int len; | |
451 | ||
452 | DBG(debug("packet_start[%d]", type)); | |
453 | len = compat20 ? 6 : 9; | |
454 | memset(buf, 0, len - 1); | |
455 | buf[len - 1] = type; | |
456 | buffer_clear(&outgoing_packet); | |
457 | buffer_append(&outgoing_packet, buf, len); | |
458 | } | |
459 | ||
460 | /* Append payload. */ | |
461 | void | |
462 | packet_put_char(int value) | |
463 | { | |
464 | char ch = value; | |
d03f4262 | 465 | |
3c0ef626 | 466 | buffer_append(&outgoing_packet, &ch, 1); |
467 | } | |
468 | void | |
469 | packet_put_int(u_int value) | |
470 | { | |
471 | buffer_put_int(&outgoing_packet, value); | |
472 | } | |
473 | void | |
1e608e42 | 474 | packet_put_string(const void *buf, u_int len) |
3c0ef626 | 475 | { |
476 | buffer_put_string(&outgoing_packet, buf, len); | |
477 | } | |
478 | void | |
479 | packet_put_cstring(const char *str) | |
480 | { | |
481 | buffer_put_cstring(&outgoing_packet, str); | |
482 | } | |
483 | void | |
1e608e42 | 484 | packet_put_raw(const void *buf, u_int len) |
3c0ef626 | 485 | { |
486 | buffer_append(&outgoing_packet, buf, len); | |
487 | } | |
488 | void | |
489 | packet_put_bignum(BIGNUM * value) | |
490 | { | |
491 | buffer_put_bignum(&outgoing_packet, value); | |
492 | } | |
493 | void | |
494 | packet_put_bignum2(BIGNUM * value) | |
495 | { | |
496 | buffer_put_bignum2(&outgoing_packet, value); | |
497 | } | |
498 | ||
499 | /* | |
500 | * Finalizes and sends the packet. If the encryption key has been set, | |
501 | * encrypts the packet before sending. | |
502 | */ | |
503 | ||
504 | static void | |
505 | packet_send1(void) | |
506 | { | |
1e608e42 | 507 | u_char buf[8], *cp; |
3c0ef626 | 508 | int i, padding, len; |
509 | u_int checksum; | |
7e82606e | 510 | u_int32_t rnd = 0; |
3c0ef626 | 511 | |
512 | /* | |
513 | * If using packet compression, compress the payload of the outgoing | |
514 | * packet. | |
515 | */ | |
516 | if (packet_compression) { | |
517 | buffer_clear(&compression_buffer); | |
518 | /* Skip padding. */ | |
519 | buffer_consume(&outgoing_packet, 8); | |
520 | /* padding */ | |
521 | buffer_append(&compression_buffer, "\0\0\0\0\0\0\0\0", 8); | |
522 | buffer_compress(&outgoing_packet, &compression_buffer); | |
523 | buffer_clear(&outgoing_packet); | |
524 | buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer), | |
1e608e42 | 525 | buffer_len(&compression_buffer)); |
3c0ef626 | 526 | } |
527 | /* Compute packet length without padding (add checksum, remove padding). */ | |
528 | len = buffer_len(&outgoing_packet) + 4 - 8; | |
529 | ||
530 | /* Insert padding. Initialized to zero in packet_start1() */ | |
531 | padding = 8 - len % 8; | |
1e608e42 | 532 | if (!send_context.plaintext) { |
3c0ef626 | 533 | cp = buffer_ptr(&outgoing_packet); |
534 | for (i = 0; i < padding; i++) { | |
535 | if (i % 4 == 0) | |
7e82606e | 536 | rnd = arc4random(); |
537 | cp[7 - i] = rnd & 0xff; | |
538 | rnd >>= 8; | |
3c0ef626 | 539 | } |
540 | } | |
541 | buffer_consume(&outgoing_packet, 8 - padding); | |
542 | ||
543 | /* Add check bytes. */ | |
1e608e42 | 544 | checksum = ssh_crc32(buffer_ptr(&outgoing_packet), |
3c0ef626 | 545 | buffer_len(&outgoing_packet)); |
546 | PUT_32BIT(buf, checksum); | |
547 | buffer_append(&outgoing_packet, buf, 4); | |
548 | ||
549 | #ifdef PACKET_DEBUG | |
550 | fprintf(stderr, "packet_send plain: "); | |
551 | buffer_dump(&outgoing_packet); | |
552 | #endif | |
553 | ||
554 | /* Append to output. */ | |
555 | PUT_32BIT(buf, len); | |
556 | buffer_append(&output, buf, 4); | |
1e608e42 | 557 | cp = buffer_append_space(&output, buffer_len(&outgoing_packet)); |
558 | cipher_crypt(&send_context, cp, buffer_ptr(&outgoing_packet), | |
559 | buffer_len(&outgoing_packet)); | |
3c0ef626 | 560 | |
561 | #ifdef PACKET_DEBUG | |
562 | fprintf(stderr, "encrypted: "); | |
563 | buffer_dump(&output); | |
564 | #endif | |
565 | ||
566 | buffer_clear(&outgoing_packet); | |
567 | ||
568 | /* | |
569 | * Note that the packet is now only buffered in output. It won\'t be | |
570 | * actually sent until packet_write_wait or packet_write_poll is | |
571 | * called. | |
572 | */ | |
573 | } | |
574 | ||
510132b6 | 575 | void |
3c0ef626 | 576 | set_newkeys(int mode) |
577 | { | |
578 | Enc *enc; | |
579 | Mac *mac; | |
580 | Comp *comp; | |
581 | CipherContext *cc; | |
7cac2b65 | 582 | u_int64_t *max_blocks; |
7e82606e | 583 | int crypt_type; |
3c0ef626 | 584 | |
bfe49944 | 585 | debug2("set_newkeys: mode %d", mode); |
3c0ef626 | 586 | |
1e608e42 | 587 | if (mode == MODE_OUT) { |
588 | cc = &send_context; | |
7e82606e | 589 | crypt_type = CIPHER_ENCRYPT; |
7cac2b65 | 590 | p_send.packets = p_send.blocks = 0; |
591 | max_blocks = &max_blocks_out; | |
1e608e42 | 592 | } else { |
593 | cc = &receive_context; | |
7e82606e | 594 | crypt_type = CIPHER_DECRYPT; |
7cac2b65 | 595 | p_read.packets = p_read.blocks = 0; |
596 | max_blocks = &max_blocks_in; | |
1e608e42 | 597 | } |
3c0ef626 | 598 | if (newkeys[mode] != NULL) { |
bfe49944 | 599 | debug("set_newkeys: rekeying"); |
1e608e42 | 600 | cipher_cleanup(cc); |
3c0ef626 | 601 | enc = &newkeys[mode]->enc; |
602 | mac = &newkeys[mode]->mac; | |
603 | comp = &newkeys[mode]->comp; | |
604 | memset(mac->key, 0, mac->key_len); | |
605 | xfree(enc->name); | |
606 | xfree(enc->iv); | |
607 | xfree(enc->key); | |
608 | xfree(mac->name); | |
609 | xfree(mac->key); | |
610 | xfree(comp->name); | |
611 | xfree(newkeys[mode]); | |
612 | } | |
613 | newkeys[mode] = kex_get_newkeys(mode); | |
614 | if (newkeys[mode] == NULL) | |
615 | fatal("newkeys: no keys for mode %d", mode); | |
616 | enc = &newkeys[mode]->enc; | |
617 | mac = &newkeys[mode]->mac; | |
618 | comp = &newkeys[mode]->comp; | |
619 | if (mac->md != NULL) | |
620 | mac->enabled = 1; | |
621 | DBG(debug("cipher_init_context: %d", mode)); | |
1e608e42 | 622 | cipher_init(cc, enc->cipher, enc->key, enc->key_len, |
7e82606e | 623 | enc->iv, enc->block_size, crypt_type); |
510132b6 | 624 | /* Deleting the keys does not gain extra security */ |
625 | /* memset(enc->iv, 0, enc->block_size); | |
626 | memset(enc->key, 0, enc->key_len); */ | |
3c0ef626 | 627 | if (comp->type != 0 && comp->enabled == 0) { |
628 | packet_init_compression(); | |
629 | if (mode == MODE_OUT) | |
630 | buffer_compress_init_send(6); | |
631 | else | |
632 | buffer_compress_init_recv(); | |
633 | comp->enabled = 1; | |
634 | } | |
7cac2b65 | 635 | /* |
636 | * The 2^(blocksize*2) limit is too expensive for 3DES, | |
637 | * blowfish, etc, so enforce a 1GB limit for small blocksizes. | |
638 | */ | |
639 | if (enc->block_size >= 16) | |
640 | *max_blocks = (u_int64_t)1 << (enc->block_size*2); | |
641 | else | |
642 | *max_blocks = ((u_int64_t)1 << 30) / enc->block_size; | |
643 | if (rekey_limit) | |
644 | *max_blocks = MIN(*max_blocks, rekey_limit / enc->block_size); | |
3c0ef626 | 645 | } |
646 | ||
647 | /* | |
648 | * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue) | |
649 | */ | |
650 | static void | |
7cac2b65 | 651 | packet_send2_wrapped(void) |
3c0ef626 | 652 | { |
1e608e42 | 653 | u_char type, *cp, *macbuf = NULL; |
3c0ef626 | 654 | u_char padlen, pad; |
3c0ef626 | 655 | u_int packet_length = 0; |
656 | u_int i, len; | |
7e82606e | 657 | u_int32_t rnd = 0; |
3c0ef626 | 658 | Enc *enc = NULL; |
659 | Mac *mac = NULL; | |
660 | Comp *comp = NULL; | |
661 | int block_size; | |
662 | ||
663 | if (newkeys[MODE_OUT] != NULL) { | |
664 | enc = &newkeys[MODE_OUT]->enc; | |
665 | mac = &newkeys[MODE_OUT]->mac; | |
666 | comp = &newkeys[MODE_OUT]->comp; | |
667 | } | |
1e608e42 | 668 | block_size = enc ? enc->block_size : 8; |
3c0ef626 | 669 | |
1e608e42 | 670 | cp = buffer_ptr(&outgoing_packet); |
671 | type = cp[5]; | |
3c0ef626 | 672 | |
673 | #ifdef PACKET_DEBUG | |
674 | fprintf(stderr, "plain: "); | |
675 | buffer_dump(&outgoing_packet); | |
676 | #endif | |
677 | ||
678 | if (comp && comp->enabled) { | |
679 | len = buffer_len(&outgoing_packet); | |
680 | /* skip header, compress only payload */ | |
681 | buffer_consume(&outgoing_packet, 5); | |
682 | buffer_clear(&compression_buffer); | |
683 | buffer_compress(&outgoing_packet, &compression_buffer); | |
684 | buffer_clear(&outgoing_packet); | |
685 | buffer_append(&outgoing_packet, "\0\0\0\0\0", 5); | |
686 | buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer), | |
687 | buffer_len(&compression_buffer)); | |
688 | DBG(debug("compression: raw %d compressed %d", len, | |
689 | buffer_len(&outgoing_packet))); | |
690 | } | |
691 | ||
692 | /* sizeof (packet_len + pad_len + payload) */ | |
693 | len = buffer_len(&outgoing_packet); | |
694 | ||
695 | /* | |
696 | * calc size of padding, alloc space, get random data, | |
697 | * minimum padding is 4 bytes | |
698 | */ | |
699 | padlen = block_size - (len % block_size); | |
700 | if (padlen < 4) | |
701 | padlen += block_size; | |
702 | if (extra_pad) { | |
703 | /* will wrap if extra_pad+padlen > 255 */ | |
704 | extra_pad = roundup(extra_pad, block_size); | |
705 | pad = extra_pad - ((len + padlen) % extra_pad); | |
510132b6 | 706 | debug3("packet_send2: adding %d (len %d padlen %d extra_pad %d)", |
3c0ef626 | 707 | pad, len, padlen, extra_pad); |
708 | padlen += pad; | |
709 | extra_pad = 0; | |
710 | } | |
1e608e42 | 711 | cp = buffer_append_space(&outgoing_packet, padlen); |
712 | if (enc && !send_context.plaintext) { | |
3c0ef626 | 713 | /* random padding */ |
714 | for (i = 0; i < padlen; i++) { | |
715 | if (i % 4 == 0) | |
7e82606e | 716 | rnd = arc4random(); |
717 | cp[i] = rnd & 0xff; | |
718 | rnd >>= 8; | |
3c0ef626 | 719 | } |
720 | } else { | |
721 | /* clear padding */ | |
722 | memset(cp, 0, padlen); | |
723 | } | |
724 | /* packet_length includes payload, padding and padding length field */ | |
725 | packet_length = buffer_len(&outgoing_packet) - 4; | |
1e608e42 | 726 | cp = buffer_ptr(&outgoing_packet); |
727 | PUT_32BIT(cp, packet_length); | |
728 | cp[4] = padlen; | |
3c0ef626 | 729 | DBG(debug("send: len %d (includes padlen %d)", packet_length+4, padlen)); |
730 | ||
731 | /* compute MAC over seqnr and packet(length fields, payload, padding) */ | |
732 | if (mac && mac->enabled) { | |
7cac2b65 | 733 | macbuf = mac_compute(mac, p_send.seqnr, |
1e608e42 | 734 | buffer_ptr(&outgoing_packet), |
3c0ef626 | 735 | buffer_len(&outgoing_packet)); |
7cac2b65 | 736 | DBG(debug("done calc MAC out #%d", p_send.seqnr)); |
3c0ef626 | 737 | } |
738 | /* encrypt packet and append to output buffer. */ | |
1e608e42 | 739 | cp = buffer_append_space(&output, buffer_len(&outgoing_packet)); |
740 | cipher_crypt(&send_context, cp, buffer_ptr(&outgoing_packet), | |
3c0ef626 | 741 | buffer_len(&outgoing_packet)); |
742 | /* append unencrypted MAC */ | |
743 | if (mac && mac->enabled) | |
744 | buffer_append(&output, (char *)macbuf, mac->mac_len); | |
745 | #ifdef PACKET_DEBUG | |
746 | fprintf(stderr, "encrypted: "); | |
747 | buffer_dump(&output); | |
748 | #endif | |
749 | /* increment sequence number for outgoing packets */ | |
7cac2b65 | 750 | if (++p_send.seqnr == 0) |
751 | logit("outgoing seqnr wraps around"); | |
752 | if (++p_send.packets == 0) | |
753 | if (!(datafellows & SSH_BUG_NOREKEY)) | |
754 | fatal("XXX too many packets with same key"); | |
755 | p_send.blocks += (packet_length + 4) / block_size; | |
3c0ef626 | 756 | buffer_clear(&outgoing_packet); |
757 | ||
758 | if (type == SSH2_MSG_NEWKEYS) | |
759 | set_newkeys(MODE_OUT); | |
760 | } | |
761 | ||
7cac2b65 | 762 | static void |
763 | packet_send2(void) | |
764 | { | |
765 | static int rekeying = 0; | |
766 | struct packet *p; | |
767 | u_char type, *cp; | |
768 | ||
769 | cp = buffer_ptr(&outgoing_packet); | |
770 | type = cp[5]; | |
771 | ||
772 | /* during rekeying we can only send key exchange messages */ | |
773 | if (rekeying) { | |
774 | if (!((type >= SSH2_MSG_TRANSPORT_MIN) && | |
775 | (type <= SSH2_MSG_TRANSPORT_MAX))) { | |
776 | debug("enqueue packet: %u", type); | |
777 | p = xmalloc(sizeof(*p)); | |
778 | p->type = type; | |
779 | memcpy(&p->payload, &outgoing_packet, sizeof(Buffer)); | |
780 | buffer_init(&outgoing_packet); | |
781 | TAILQ_INSERT_TAIL(&outgoing, p, next); | |
782 | return; | |
783 | } | |
784 | } | |
785 | ||
786 | /* rekeying starts with sending KEXINIT */ | |
787 | if (type == SSH2_MSG_KEXINIT) | |
788 | rekeying = 1; | |
789 | ||
790 | packet_send2_wrapped(); | |
791 | ||
792 | /* after a NEWKEYS message we can send the complete queue */ | |
793 | if (type == SSH2_MSG_NEWKEYS) { | |
794 | rekeying = 0; | |
795 | while ((p = TAILQ_FIRST(&outgoing))) { | |
796 | type = p->type; | |
797 | debug("dequeue packet: %u", type); | |
798 | buffer_free(&outgoing_packet); | |
799 | memcpy(&outgoing_packet, &p->payload, | |
800 | sizeof(Buffer)); | |
801 | TAILQ_REMOVE(&outgoing, p, next); | |
802 | xfree(p); | |
803 | packet_send2_wrapped(); | |
804 | } | |
805 | } | |
806 | } | |
807 | ||
3c0ef626 | 808 | void |
1e608e42 | 809 | packet_send(void) |
3c0ef626 | 810 | { |
811 | if (compat20) | |
812 | packet_send2(); | |
813 | else | |
814 | packet_send1(); | |
815 | DBG(debug("packet_send done")); | |
816 | } | |
817 | ||
818 | /* | |
819 | * Waits until a packet has been received, and returns its type. Note that | |
820 | * no other data is processed until this returns, so this function should not | |
821 | * be used during the interactive session. | |
822 | */ | |
823 | ||
824 | int | |
1e608e42 | 825 | packet_read_seqnr(u_int32_t *seqnr_p) |
3c0ef626 | 826 | { |
827 | int type, len; | |
828 | fd_set *setp; | |
829 | char buf[8192]; | |
830 | DBG(debug("packet_read()")); | |
831 | ||
832 | setp = (fd_set *)xmalloc(howmany(connection_in+1, NFDBITS) * | |
833 | sizeof(fd_mask)); | |
834 | ||
835 | /* Since we are blocking, ensure that all written packets have been sent. */ | |
836 | packet_write_wait(); | |
837 | ||
838 | /* Stay in the loop until we have received a complete packet. */ | |
839 | for (;;) { | |
840 | /* Try to read a packet from the buffer. */ | |
1e608e42 | 841 | type = packet_read_poll_seqnr(seqnr_p); |
3c0ef626 | 842 | if (!compat20 && ( |
843 | type == SSH_SMSG_SUCCESS | |
844 | || type == SSH_SMSG_FAILURE | |
845 | || type == SSH_CMSG_EOF | |
846 | || type == SSH_CMSG_EXIT_CONFIRMATION)) | |
1e608e42 | 847 | packet_check_eom(); |
3c0ef626 | 848 | /* If we got a packet, return it. */ |
849 | if (type != SSH_MSG_NONE) { | |
850 | xfree(setp); | |
851 | return type; | |
852 | } | |
853 | /* | |
854 | * Otherwise, wait for some data to arrive, add it to the | |
855 | * buffer, and try again. | |
856 | */ | |
857 | memset(setp, 0, howmany(connection_in + 1, NFDBITS) * | |
858 | sizeof(fd_mask)); | |
859 | FD_SET(connection_in, setp); | |
860 | ||
861 | /* Wait for some data to arrive. */ | |
862 | while (select(connection_in + 1, setp, NULL, NULL, NULL) == -1 && | |
863 | (errno == EAGAIN || errno == EINTR)) | |
864 | ; | |
865 | ||
866 | /* Read data from the socket. */ | |
867 | len = read(connection_in, buf, sizeof(buf)); | |
868 | if (len == 0) { | |
7cac2b65 | 869 | logit("Connection closed by %.200s", get_remote_ipaddr()); |
540d72c3 | 870 | cleanup_exit(255); |
3c0ef626 | 871 | } |
872 | if (len < 0) | |
873 | fatal("Read from socket failed: %.100s", strerror(errno)); | |
874 | /* Append it to the buffer. */ | |
875 | packet_process_incoming(buf, len); | |
876 | } | |
877 | /* NOTREACHED */ | |
878 | } | |
879 | ||
1e608e42 | 880 | int |
881 | packet_read(void) | |
882 | { | |
883 | return packet_read_seqnr(NULL); | |
884 | } | |
885 | ||
3c0ef626 | 886 | /* |
887 | * Waits until a packet has been received, verifies that its type matches | |
888 | * that given, and gives a fatal error and exits if there is a mismatch. | |
889 | */ | |
890 | ||
891 | void | |
1e608e42 | 892 | packet_read_expect(int expected_type) |
3c0ef626 | 893 | { |
894 | int type; | |
895 | ||
1e608e42 | 896 | type = packet_read(); |
3c0ef626 | 897 | if (type != expected_type) |
898 | packet_disconnect("Protocol error: expected packet type %d, got %d", | |
899 | expected_type, type); | |
900 | } | |
901 | ||
902 | /* Checks if a full packet is available in the data received so far via | |
903 | * packet_process_incoming. If so, reads the packet; otherwise returns | |
904 | * SSH_MSG_NONE. This does not wait for data from the connection. | |
905 | * | |
906 | * SSH_MSG_DISCONNECT is handled specially here. Also, | |
907 | * SSH_MSG_IGNORE messages are skipped by this function and are never returned | |
908 | * to higher levels. | |
3c0ef626 | 909 | */ |
910 | ||
911 | static int | |
1e608e42 | 912 | packet_read_poll1(void) |
3c0ef626 | 913 | { |
914 | u_int len, padded_len; | |
1e608e42 | 915 | u_char *cp, type; |
3c0ef626 | 916 | u_int checksum, stored_checksum; |
917 | ||
918 | /* Check if input size is less than minimum packet size. */ | |
919 | if (buffer_len(&input) < 4 + 8) | |
920 | return SSH_MSG_NONE; | |
921 | /* Get length of incoming packet. */ | |
1e608e42 | 922 | cp = buffer_ptr(&input); |
923 | len = GET_32BIT(cp); | |
3c0ef626 | 924 | if (len < 1 + 2 + 2 || len > 256 * 1024) |
bfe49944 | 925 | packet_disconnect("Bad packet length %u.", len); |
3c0ef626 | 926 | padded_len = (len + 8) & ~7; |
927 | ||
928 | /* Check if the packet has been entirely received. */ | |
929 | if (buffer_len(&input) < 4 + padded_len) | |
930 | return SSH_MSG_NONE; | |
931 | ||
932 | /* The entire packet is in buffer. */ | |
933 | ||
934 | /* Consume packet length. */ | |
935 | buffer_consume(&input, 4); | |
936 | ||
937 | /* | |
938 | * Cryptographic attack detector for ssh | |
939 | * (C)1998 CORE-SDI, Buenos Aires Argentina | |
940 | * Ariel Futoransky(futo@core-sdi.com) | |
941 | */ | |
1e608e42 | 942 | if (!receive_context.plaintext && |
3c0ef626 | 943 | detect_attack(buffer_ptr(&input), padded_len, NULL) == DEATTACK_DETECTED) |
944 | packet_disconnect("crc32 compensation attack: network attack detected"); | |
945 | ||
946 | /* Decrypt data to incoming_packet. */ | |
947 | buffer_clear(&incoming_packet); | |
1e608e42 | 948 | cp = buffer_append_space(&incoming_packet, padded_len); |
949 | cipher_crypt(&receive_context, cp, buffer_ptr(&input), padded_len); | |
3c0ef626 | 950 | |
951 | buffer_consume(&input, padded_len); | |
952 | ||
953 | #ifdef PACKET_DEBUG | |
954 | fprintf(stderr, "read_poll plain: "); | |
955 | buffer_dump(&incoming_packet); | |
956 | #endif | |
957 | ||
958 | /* Compute packet checksum. */ | |
1e608e42 | 959 | checksum = ssh_crc32(buffer_ptr(&incoming_packet), |
3c0ef626 | 960 | buffer_len(&incoming_packet) - 4); |
961 | ||
962 | /* Skip padding. */ | |
963 | buffer_consume(&incoming_packet, 8 - len % 8); | |
964 | ||
965 | /* Test check bytes. */ | |
966 | if (len != buffer_len(&incoming_packet)) | |
1e608e42 | 967 | packet_disconnect("packet_read_poll1: len %d != buffer_len %d.", |
3c0ef626 | 968 | len, buffer_len(&incoming_packet)); |
969 | ||
1e608e42 | 970 | cp = (u_char *)buffer_ptr(&incoming_packet) + len - 4; |
971 | stored_checksum = GET_32BIT(cp); | |
3c0ef626 | 972 | if (checksum != stored_checksum) |
973 | packet_disconnect("Corrupted check bytes on input."); | |
974 | buffer_consume_end(&incoming_packet, 4); | |
975 | ||
976 | if (packet_compression) { | |
977 | buffer_clear(&compression_buffer); | |
978 | buffer_uncompress(&incoming_packet, &compression_buffer); | |
979 | buffer_clear(&incoming_packet); | |
980 | buffer_append(&incoming_packet, buffer_ptr(&compression_buffer), | |
981 | buffer_len(&compression_buffer)); | |
982 | } | |
983 | type = buffer_get_char(&incoming_packet); | |
3c0ef626 | 984 | return type; |
985 | } | |
986 | ||
987 | static int | |
1e608e42 | 988 | packet_read_poll2(u_int32_t *seqnr_p) |
3c0ef626 | 989 | { |
3c0ef626 | 990 | static u_int packet_length = 0; |
991 | u_int padlen, need; | |
1e608e42 | 992 | u_char *macbuf, *cp, type; |
3c0ef626 | 993 | int maclen, block_size; |
994 | Enc *enc = NULL; | |
995 | Mac *mac = NULL; | |
996 | Comp *comp = NULL; | |
997 | ||
998 | if (newkeys[MODE_IN] != NULL) { | |
999 | enc = &newkeys[MODE_IN]->enc; | |
1000 | mac = &newkeys[MODE_IN]->mac; | |
1001 | comp = &newkeys[MODE_IN]->comp; | |
1002 | } | |
1003 | maclen = mac && mac->enabled ? mac->mac_len : 0; | |
1e608e42 | 1004 | block_size = enc ? enc->block_size : 8; |
3c0ef626 | 1005 | |
1006 | if (packet_length == 0) { | |
1007 | /* | |
1008 | * check if input size is less than the cipher block size, | |
1009 | * decrypt first block and extract length of incoming packet | |
1010 | */ | |
1011 | if (buffer_len(&input) < block_size) | |
1012 | return SSH_MSG_NONE; | |
1013 | buffer_clear(&incoming_packet); | |
1e608e42 | 1014 | cp = buffer_append_space(&incoming_packet, block_size); |
1015 | cipher_crypt(&receive_context, cp, buffer_ptr(&input), | |
3c0ef626 | 1016 | block_size); |
1e608e42 | 1017 | cp = buffer_ptr(&incoming_packet); |
1018 | packet_length = GET_32BIT(cp); | |
3c0ef626 | 1019 | if (packet_length < 1 + 4 || packet_length > 256 * 1024) { |
29d88157 | 1020 | #ifdef PACKET_DEBUG |
3c0ef626 | 1021 | buffer_dump(&incoming_packet); |
29d88157 | 1022 | #endif |
bfe49944 | 1023 | packet_disconnect("Bad packet length %u.", packet_length); |
3c0ef626 | 1024 | } |
bfe49944 | 1025 | DBG(debug("input: packet len %u", packet_length+4)); |
3c0ef626 | 1026 | buffer_consume(&input, block_size); |
1027 | } | |
1028 | /* we have a partial packet of block_size bytes */ | |
1029 | need = 4 + packet_length - block_size; | |
1030 | DBG(debug("partial packet %d, need %d, maclen %d", block_size, | |
1031 | need, maclen)); | |
1032 | if (need % block_size != 0) | |
1033 | fatal("padding error: need %d block %d mod %d", | |
1034 | need, block_size, need % block_size); | |
1035 | /* | |
1036 | * check if the entire packet has been received and | |
1037 | * decrypt into incoming_packet | |
1038 | */ | |
1039 | if (buffer_len(&input) < need + maclen) | |
1040 | return SSH_MSG_NONE; | |
1041 | #ifdef PACKET_DEBUG | |
1042 | fprintf(stderr, "read_poll enc/full: "); | |
1043 | buffer_dump(&input); | |
1044 | #endif | |
1e608e42 | 1045 | cp = buffer_append_space(&incoming_packet, need); |
1046 | cipher_crypt(&receive_context, cp, buffer_ptr(&input), need); | |
3c0ef626 | 1047 | buffer_consume(&input, need); |
1048 | /* | |
1049 | * compute MAC over seqnr and packet, | |
1050 | * increment sequence number for incoming packet | |
1051 | */ | |
1052 | if (mac && mac->enabled) { | |
7cac2b65 | 1053 | macbuf = mac_compute(mac, p_read.seqnr, |
1e608e42 | 1054 | buffer_ptr(&incoming_packet), |
3c0ef626 | 1055 | buffer_len(&incoming_packet)); |
1056 | if (memcmp(macbuf, buffer_ptr(&input), mac->mac_len) != 0) | |
1057 | packet_disconnect("Corrupted MAC on input."); | |
7cac2b65 | 1058 | DBG(debug("MAC #%d ok", p_read.seqnr)); |
3c0ef626 | 1059 | buffer_consume(&input, mac->mac_len); |
1060 | } | |
1e608e42 | 1061 | if (seqnr_p != NULL) |
7cac2b65 | 1062 | *seqnr_p = p_read.seqnr; |
1063 | if (++p_read.seqnr == 0) | |
1064 | logit("incoming seqnr wraps around"); | |
1065 | if (++p_read.packets == 0) | |
1066 | if (!(datafellows & SSH_BUG_NOREKEY)) | |
1067 | fatal("XXX too many packets with same key"); | |
1068 | p_read.blocks += (packet_length + 4) / block_size; | |
3c0ef626 | 1069 | |
1070 | /* get padlen */ | |
1e608e42 | 1071 | cp = buffer_ptr(&incoming_packet); |
1072 | padlen = cp[4]; | |
3c0ef626 | 1073 | DBG(debug("input: padlen %d", padlen)); |
1074 | if (padlen < 4) | |
1075 | packet_disconnect("Corrupted padlen %d on input.", padlen); | |
1076 | ||
1077 | /* skip packet size + padlen, discard padding */ | |
1078 | buffer_consume(&incoming_packet, 4 + 1); | |
1079 | buffer_consume_end(&incoming_packet, padlen); | |
1080 | ||
1081 | DBG(debug("input: len before de-compress %d", buffer_len(&incoming_packet))); | |
1082 | if (comp && comp->enabled) { | |
1083 | buffer_clear(&compression_buffer); | |
1084 | buffer_uncompress(&incoming_packet, &compression_buffer); | |
1085 | buffer_clear(&incoming_packet); | |
1086 | buffer_append(&incoming_packet, buffer_ptr(&compression_buffer), | |
1087 | buffer_len(&compression_buffer)); | |
d03f4262 | 1088 | DBG(debug("input: len after de-compress %d", |
1089 | buffer_len(&incoming_packet))); | |
3c0ef626 | 1090 | } |
1091 | /* | |
1092 | * get packet type, implies consume. | |
1093 | * return length of payload (without type field) | |
1094 | */ | |
1095 | type = buffer_get_char(&incoming_packet); | |
1096 | if (type == SSH2_MSG_NEWKEYS) | |
1097 | set_newkeys(MODE_IN); | |
3c0ef626 | 1098 | #ifdef PACKET_DEBUG |
1099 | fprintf(stderr, "read/plain[%d]:\r\n", type); | |
1100 | buffer_dump(&incoming_packet); | |
1101 | #endif | |
1102 | /* reset for next packet */ | |
1103 | packet_length = 0; | |
1104 | return type; | |
1105 | } | |
1106 | ||
1107 | int | |
1e608e42 | 1108 | packet_read_poll_seqnr(u_int32_t *seqnr_p) |
3c0ef626 | 1109 | { |
276b07a3 | 1110 | u_int reason, seqnr; |
3c0ef626 | 1111 | u_char type; |
1112 | char *msg; | |
1113 | ||
1114 | for (;;) { | |
1115 | if (compat20) { | |
1e608e42 | 1116 | type = packet_read_poll2(seqnr_p); |
3c0ef626 | 1117 | if (type) |
1118 | DBG(debug("received packet type %d", type)); | |
1e608e42 | 1119 | switch (type) { |
3c0ef626 | 1120 | case SSH2_MSG_IGNORE: |
1121 | break; | |
1122 | case SSH2_MSG_DEBUG: | |
1123 | packet_get_char(); | |
1124 | msg = packet_get_string(NULL); | |
1125 | debug("Remote: %.900s", msg); | |
1126 | xfree(msg); | |
1127 | msg = packet_get_string(NULL); | |
1128 | xfree(msg); | |
1129 | break; | |
1130 | case SSH2_MSG_DISCONNECT: | |
1131 | reason = packet_get_int(); | |
1132 | msg = packet_get_string(NULL); | |
7cac2b65 | 1133 | logit("Received disconnect from %s: %u: %.400s", |
276b07a3 | 1134 | get_remote_ipaddr(), reason, msg); |
3c0ef626 | 1135 | xfree(msg); |
540d72c3 | 1136 | cleanup_exit(255); |
3c0ef626 | 1137 | break; |
1e608e42 | 1138 | case SSH2_MSG_UNIMPLEMENTED: |
1139 | seqnr = packet_get_int(); | |
276b07a3 | 1140 | debug("Received SSH2_MSG_UNIMPLEMENTED for %u", |
1141 | seqnr); | |
1e608e42 | 1142 | break; |
3c0ef626 | 1143 | default: |
1144 | return type; | |
1145 | break; | |
1146 | } | |
1147 | } else { | |
1e608e42 | 1148 | type = packet_read_poll1(); |
1149 | switch (type) { | |
3c0ef626 | 1150 | case SSH_MSG_IGNORE: |
1151 | break; | |
1152 | case SSH_MSG_DEBUG: | |
1153 | msg = packet_get_string(NULL); | |
1154 | debug("Remote: %.900s", msg); | |
1155 | xfree(msg); | |
1156 | break; | |
1157 | case SSH_MSG_DISCONNECT: | |
1158 | msg = packet_get_string(NULL); | |
7cac2b65 | 1159 | logit("Received disconnect from %s: %.400s", |
276b07a3 | 1160 | get_remote_ipaddr(), msg); |
540d72c3 | 1161 | cleanup_exit(255); |
3c0ef626 | 1162 | xfree(msg); |
1163 | break; | |
1164 | default: | |
1165 | if (type) | |
1166 | DBG(debug("received packet type %d", type)); | |
1167 | return type; | |
1168 | break; | |
1169 | } | |
1170 | } | |
1171 | } | |
1172 | } | |
1173 | ||
1e608e42 | 1174 | int |
1175 | packet_read_poll(void) | |
1176 | { | |
1177 | return packet_read_poll_seqnr(NULL); | |
1178 | } | |
1179 | ||
3c0ef626 | 1180 | /* |
1181 | * Buffers the given amount of input characters. This is intended to be used | |
1182 | * together with packet_read_poll. | |
1183 | */ | |
1184 | ||
1185 | void | |
1186 | packet_process_incoming(const char *buf, u_int len) | |
1187 | { | |
1188 | buffer_append(&input, buf, len); | |
1189 | } | |
1190 | ||
1191 | /* Returns a character from the packet. */ | |
1192 | ||
1193 | u_int | |
1e608e42 | 1194 | packet_get_char(void) |
3c0ef626 | 1195 | { |
1196 | char ch; | |
d03f4262 | 1197 | |
3c0ef626 | 1198 | buffer_get(&incoming_packet, &ch, 1); |
1199 | return (u_char) ch; | |
1200 | } | |
1201 | ||
1202 | /* Returns an integer from the packet data. */ | |
1203 | ||
1204 | u_int | |
1e608e42 | 1205 | packet_get_int(void) |
3c0ef626 | 1206 | { |
1207 | return buffer_get_int(&incoming_packet); | |
1208 | } | |
1209 | ||
1210 | /* | |
1211 | * Returns an arbitrary precision integer from the packet data. The integer | |
1212 | * must have been initialized before this call. | |
1213 | */ | |
1214 | ||
1215 | void | |
1e608e42 | 1216 | packet_get_bignum(BIGNUM * value) |
3c0ef626 | 1217 | { |
1e608e42 | 1218 | buffer_get_bignum(&incoming_packet, value); |
3c0ef626 | 1219 | } |
1220 | ||
1221 | void | |
1e608e42 | 1222 | packet_get_bignum2(BIGNUM * value) |
3c0ef626 | 1223 | { |
1e608e42 | 1224 | buffer_get_bignum2(&incoming_packet, value); |
3c0ef626 | 1225 | } |
1226 | ||
1e608e42 | 1227 | void * |
3c0ef626 | 1228 | packet_get_raw(int *length_ptr) |
1229 | { | |
1230 | int bytes = buffer_len(&incoming_packet); | |
d03f4262 | 1231 | |
3c0ef626 | 1232 | if (length_ptr != NULL) |
1233 | *length_ptr = bytes; | |
1234 | return buffer_ptr(&incoming_packet); | |
1235 | } | |
1236 | ||
1237 | int | |
1238 | packet_remaining(void) | |
1239 | { | |
1240 | return buffer_len(&incoming_packet); | |
1241 | } | |
1242 | ||
1243 | /* | |
1244 | * Returns a string from the packet data. The string is allocated using | |
1245 | * xmalloc; it is the responsibility of the calling program to free it when | |
1246 | * no longer needed. The length_ptr argument may be NULL, or point to an | |
1247 | * integer into which the length of the string is stored. | |
1248 | */ | |
1249 | ||
1e608e42 | 1250 | void * |
3c0ef626 | 1251 | packet_get_string(u_int *length_ptr) |
1252 | { | |
1253 | return buffer_get_string(&incoming_packet, length_ptr); | |
1254 | } | |
1255 | ||
1256 | /* | |
1257 | * Sends a diagnostic message from the server to the client. This message | |
1258 | * can be sent at any time (but not while constructing another message). The | |
1259 | * message is printed immediately, but only if the client is being executed | |
1260 | * in verbose mode. These messages are primarily intended to ease debugging | |
1261 | * authentication problems. The length of the formatted message must not | |
1262 | * exceed 1024 bytes. This will automatically call packet_write_wait. | |
1263 | */ | |
1264 | ||
1265 | void | |
1266 | packet_send_debug(const char *fmt,...) | |
1267 | { | |
1268 | char buf[1024]; | |
1269 | va_list args; | |
1270 | ||
1271 | if (compat20 && (datafellows & SSH_BUG_DEBUG)) | |
1272 | return; | |
1273 | ||
1274 | va_start(args, fmt); | |
1275 | vsnprintf(buf, sizeof(buf), fmt, args); | |
1276 | va_end(args); | |
1277 | ||
1278 | if (compat20) { | |
1279 | packet_start(SSH2_MSG_DEBUG); | |
1280 | packet_put_char(0); /* bool: always display */ | |
1281 | packet_put_cstring(buf); | |
1282 | packet_put_cstring(""); | |
1283 | } else { | |
1284 | packet_start(SSH_MSG_DEBUG); | |
1285 | packet_put_cstring(buf); | |
1286 | } | |
1287 | packet_send(); | |
1288 | packet_write_wait(); | |
1289 | } | |
1290 | ||
1291 | /* | |
1292 | * Logs the error plus constructs and sends a disconnect packet, closes the | |
1293 | * connection, and exits. This function never returns. The error message | |
1294 | * should not contain a newline. The length of the formatted message must | |
1295 | * not exceed 1024 bytes. | |
1296 | */ | |
1297 | ||
1298 | void | |
1299 | packet_disconnect(const char *fmt,...) | |
1300 | { | |
1301 | char buf[1024]; | |
1302 | va_list args; | |
1303 | static int disconnecting = 0; | |
d03f4262 | 1304 | |
3c0ef626 | 1305 | if (disconnecting) /* Guard against recursive invocations. */ |
1306 | fatal("packet_disconnect called recursively."); | |
1307 | disconnecting = 1; | |
1308 | ||
1309 | /* | |
1310 | * Format the message. Note that the caller must make sure the | |
1311 | * message is of limited size. | |
1312 | */ | |
1313 | va_start(args, fmt); | |
1314 | vsnprintf(buf, sizeof(buf), fmt, args); | |
1315 | va_end(args); | |
1316 | ||
bfe49944 | 1317 | /* Display the error locally */ |
7cac2b65 | 1318 | logit("Disconnecting: %.100s", buf); |
bfe49944 | 1319 | |
3c0ef626 | 1320 | /* Send the disconnect message to the other side, and wait for it to get sent. */ |
1321 | if (compat20) { | |
1322 | packet_start(SSH2_MSG_DISCONNECT); | |
1323 | packet_put_int(SSH2_DISCONNECT_PROTOCOL_ERROR); | |
1324 | packet_put_cstring(buf); | |
1325 | packet_put_cstring(""); | |
1326 | } else { | |
1327 | packet_start(SSH_MSG_DISCONNECT); | |
1328 | packet_put_cstring(buf); | |
1329 | } | |
1330 | packet_send(); | |
1331 | packet_write_wait(); | |
1332 | ||
1333 | /* Stop listening for connections. */ | |
1334 | channel_close_all(); | |
1335 | ||
1336 | /* Close the connection. */ | |
1337 | packet_close(); | |
540d72c3 | 1338 | cleanup_exit(255); |
3c0ef626 | 1339 | } |
1340 | ||
1341 | /* Checks if there is any buffered output, and tries to write some of the output. */ | |
1342 | ||
1343 | void | |
1e608e42 | 1344 | packet_write_poll(void) |
3c0ef626 | 1345 | { |
1346 | int len = buffer_len(&output); | |
d03f4262 | 1347 | |
3c0ef626 | 1348 | if (len > 0) { |
1349 | len = write(connection_out, buffer_ptr(&output), len); | |
1350 | if (len <= 0) { | |
1351 | if (errno == EAGAIN) | |
1352 | return; | |
1353 | else | |
1354 | fatal("Write failed: %.100s", strerror(errno)); | |
1355 | } | |
1356 | buffer_consume(&output, len); | |
1357 | } | |
1358 | } | |
1359 | ||
1360 | /* | |
1361 | * Calls packet_write_poll repeatedly until all pending output data has been | |
1362 | * written. | |
1363 | */ | |
1364 | ||
1365 | void | |
1e608e42 | 1366 | packet_write_wait(void) |
3c0ef626 | 1367 | { |
1368 | fd_set *setp; | |
1369 | ||
1370 | setp = (fd_set *)xmalloc(howmany(connection_out + 1, NFDBITS) * | |
1371 | sizeof(fd_mask)); | |
1372 | packet_write_poll(); | |
1373 | while (packet_have_data_to_write()) { | |
1374 | memset(setp, 0, howmany(connection_out + 1, NFDBITS) * | |
1375 | sizeof(fd_mask)); | |
1376 | FD_SET(connection_out, setp); | |
1377 | while (select(connection_out + 1, NULL, setp, NULL, NULL) == -1 && | |
1378 | (errno == EAGAIN || errno == EINTR)) | |
1379 | ; | |
1380 | packet_write_poll(); | |
1381 | } | |
1382 | xfree(setp); | |
1383 | } | |
1384 | ||
1385 | /* Returns true if there is buffered data to write to the connection. */ | |
1386 | ||
1387 | int | |
1e608e42 | 1388 | packet_have_data_to_write(void) |
3c0ef626 | 1389 | { |
1390 | return buffer_len(&output) != 0; | |
1391 | } | |
1392 | ||
1393 | /* Returns true if there is not too much data to write to the connection. */ | |
1394 | ||
1395 | int | |
1e608e42 | 1396 | packet_not_very_much_data_to_write(void) |
3c0ef626 | 1397 | { |
1398 | if (interactive_mode) | |
1399 | return buffer_len(&output) < 16384; | |
1400 | else | |
1401 | return buffer_len(&output) < 128 * 1024; | |
1402 | } | |
1403 | ||
7cac2b65 | 1404 | |
bfe49944 | 1405 | static void |
1406 | packet_set_tos(int interactive) | |
1407 | { | |
540d72c3 | 1408 | #if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN) |
bfe49944 | 1409 | int tos = interactive ? IPTOS_LOWDELAY : IPTOS_THROUGHPUT; |
1410 | ||
1411 | if (!packet_connection_is_on_socket() || | |
1412 | !packet_connection_is_ipv4()) | |
1413 | return; | |
1414 | if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, &tos, | |
1415 | sizeof(tos)) < 0) | |
1416 | error("setsockopt IP_TOS %d: %.100s:", | |
1417 | tos, strerror(errno)); | |
7cac2b65 | 1418 | #endif |
540d72c3 | 1419 | } |
bfe49944 | 1420 | |
3c0ef626 | 1421 | /* Informs that the current session is interactive. Sets IP flags for that. */ |
1422 | ||
1423 | void | |
1424 | packet_set_interactive(int interactive) | |
1425 | { | |
1426 | static int called = 0; | |
3c0ef626 | 1427 | |
1428 | if (called) | |
1429 | return; | |
1430 | called = 1; | |
1431 | ||
1432 | /* Record that we are in interactive mode. */ | |
1433 | interactive_mode = interactive; | |
1434 | ||
1435 | /* Only set socket options if using a socket. */ | |
1436 | if (!packet_connection_is_on_socket()) | |
7cac2b65 | 1437 | return; |
bfe49944 | 1438 | if (interactive) |
1e608e42 | 1439 | set_nodelay(connection_in); |
bfe49944 | 1440 | packet_set_tos(interactive); |
3c0ef626 | 1441 | } |
1442 | ||
1443 | /* Returns true if the current connection is interactive. */ | |
1444 | ||
1445 | int | |
1e608e42 | 1446 | packet_is_interactive(void) |
3c0ef626 | 1447 | { |
1448 | return interactive_mode; | |
1449 | } | |
1450 | ||
7e82606e | 1451 | int |
7cac2b65 | 1452 | packet_set_maxsize(u_int s) |
3c0ef626 | 1453 | { |
1454 | static int called = 0; | |
d03f4262 | 1455 | |
3c0ef626 | 1456 | if (called) { |
7cac2b65 | 1457 | logit("packet_set_maxsize: called twice: old %d new %d", |
3c0ef626 | 1458 | max_packet_size, s); |
1459 | return -1; | |
1460 | } | |
1461 | if (s < 4 * 1024 || s > 1024 * 1024) { | |
7cac2b65 | 1462 | logit("packet_set_maxsize: bad size %d", s); |
3c0ef626 | 1463 | return -1; |
1464 | } | |
1465 | called = 1; | |
1466 | debug("packet_set_maxsize: setting to %d", s); | |
1467 | max_packet_size = s; | |
1468 | return s; | |
1469 | } | |
1470 | ||
1471 | /* roundup current message to pad bytes */ | |
1472 | void | |
1473 | packet_add_padding(u_char pad) | |
1474 | { | |
1475 | extra_pad = pad; | |
1476 | } | |
1477 | ||
1478 | /* | |
1479 | * 9.2. Ignored Data Message | |
1480 | * | |
1481 | * byte SSH_MSG_IGNORE | |
1482 | * string data | |
1483 | * | |
1484 | * All implementations MUST understand (and ignore) this message at any | |
1485 | * time (after receiving the protocol version). No implementation is | |
1486 | * required to send them. This message can be used as an additional | |
1487 | * protection measure against advanced traffic analysis techniques. | |
1488 | */ | |
1489 | void | |
1490 | packet_send_ignore(int nbytes) | |
1491 | { | |
7e82606e | 1492 | u_int32_t rnd = 0; |
3c0ef626 | 1493 | int i; |
1494 | ||
1495 | packet_start(compat20 ? SSH2_MSG_IGNORE : SSH_MSG_IGNORE); | |
1496 | packet_put_int(nbytes); | |
1e608e42 | 1497 | for (i = 0; i < nbytes; i++) { |
3c0ef626 | 1498 | if (i % 4 == 0) |
7e82606e | 1499 | rnd = arc4random(); |
1500 | packet_put_char(rnd & 0xff); | |
1501 | rnd >>= 8; | |
3c0ef626 | 1502 | } |
1503 | } | |
7cac2b65 | 1504 | |
7e82606e | 1505 | #define MAX_PACKETS (1U<<31) |
7cac2b65 | 1506 | int |
1507 | packet_need_rekeying(void) | |
1508 | { | |
1509 | if (datafellows & SSH_BUG_NOREKEY) | |
1510 | return 0; | |
1511 | return | |
1512 | (p_send.packets > MAX_PACKETS) || | |
1513 | (p_read.packets > MAX_PACKETS) || | |
1514 | (max_blocks_out && (p_send.blocks > max_blocks_out)) || | |
1515 | (max_blocks_in && (p_read.blocks > max_blocks_in)); | |
1516 | } | |
1517 | ||
1518 | void | |
1519 | packet_set_rekey_limit(u_int32_t bytes) | |
1520 | { | |
1521 | rekey_limit = bytes; | |
1522 | } |