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8efc0c15 | 1 | /* |
5260325f | 2 | * Author: Tatu Ylonen <ylo@cs.hut.fi> |
5260325f | 3 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland |
4 | * All rights reserved | |
5260325f | 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. | |
7e7327a1 | 7 | * |
bcbf86ec | 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 | * | |
7e7327a1 | 15 | * SSH2 packet format added by Markus Friedl. |
bcbf86ec | 16 | * Copyright (c) 2000 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. | |
7e7327a1 | 26 | * |
bcbf86ec | 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. | |
5260325f | 37 | */ |
8efc0c15 | 38 | |
39 | #include "includes.h" | |
449c5ba5 | 40 | RCSID("$OpenBSD: packet.c,v 1.65 2001/06/07 20:23:04 markus Exp $"); |
8efc0c15 | 41 | |
42 | #include "xmalloc.h" | |
43 | #include "buffer.h" | |
44 | #include "packet.h" | |
45 | #include "bufaux.h" | |
8efc0c15 | 46 | #include "crc32.h" |
8efc0c15 | 47 | #include "getput.h" |
48 | ||
49 | #include "compress.h" | |
50 | #include "deattack.h" | |
a5efa1bb | 51 | #include "channels.h" |
8efc0c15 | 52 | |
7e7327a1 | 53 | #include "compat.h" |
42f11eb2 | 54 | #include "ssh1.h" |
7e7327a1 | 55 | #include "ssh2.h" |
56 | ||
94ec8c6b | 57 | #include "cipher.h" |
7e7327a1 | 58 | #include "kex.h" |
b2552997 | 59 | #include "mac.h" |
42f11eb2 | 60 | #include "log.h" |
61 | #include "canohost.h" | |
7e7327a1 | 62 | |
63 | #ifdef PACKET_DEBUG | |
64 | #define DBG(x) x | |
65 | #else | |
66 | #define DBG(x) | |
67 | #endif | |
68 | ||
aa3378df | 69 | /* |
70 | * This variable contains the file descriptors used for communicating with | |
71 | * the other side. connection_in is used for reading; connection_out for | |
72 | * writing. These can be the same descriptor, in which case it is assumed to | |
73 | * be a socket. | |
74 | */ | |
8efc0c15 | 75 | static int connection_in = -1; |
76 | static int connection_out = -1; | |
77 | ||
8efc0c15 | 78 | /* Protocol flags for the remote side. */ |
1e3b8b07 | 79 | static u_int remote_protocol_flags = 0; |
8efc0c15 | 80 | |
81 | /* Encryption context for receiving data. This is only used for decryption. */ | |
82 | static CipherContext receive_context; | |
5260325f | 83 | |
84 | /* Encryption context for sending data. This is only used for encryption. */ | |
8efc0c15 | 85 | static CipherContext send_context; |
86 | ||
87 | /* Buffer for raw input data from the socket. */ | |
88 | static Buffer input; | |
89 | ||
90 | /* Buffer for raw output data going to the socket. */ | |
91 | static Buffer output; | |
92 | ||
93 | /* Buffer for the partial outgoing packet being constructed. */ | |
94 | static Buffer outgoing_packet; | |
95 | ||
96 | /* Buffer for the incoming packet currently being processed. */ | |
97 | static Buffer incoming_packet; | |
98 | ||
99 | /* Scratch buffer for packet compression/decompression. */ | |
100 | static Buffer compression_buffer; | |
6ba22c93 | 101 | static int compression_buffer_ready = 0; |
8efc0c15 | 102 | |
103 | /* Flag indicating whether packet compression/decompression is enabled. */ | |
104 | static int packet_compression = 0; | |
105 | ||
9d6b7add | 106 | /* default maximum packet size */ |
107 | int max_packet_size = 32768; | |
108 | ||
8efc0c15 | 109 | /* Flag indicating whether this module has been initialized. */ |
110 | static int initialized = 0; | |
111 | ||
112 | /* Set to true if the connection is interactive. */ | |
113 | static int interactive_mode = 0; | |
114 | ||
7e7327a1 | 115 | /* Session key information for Encryption and MAC */ |
d1ac6175 | 116 | Newkeys *newkeys[MODE_MAX]; |
7e7327a1 | 117 | |
aa3378df | 118 | /* |
119 | * Sets the descriptors used for communication. Disables encryption until | |
120 | * packet_set_encryption_key is called. | |
121 | */ | |
8efc0c15 | 122 | void |
123 | packet_set_connection(int fd_in, int fd_out) | |
124 | { | |
94ec8c6b | 125 | Cipher *none = cipher_by_name("none"); |
126 | if (none == NULL) | |
127 | fatal("packet_set_connection: cannot load cipher 'none'"); | |
5260325f | 128 | connection_in = fd_in; |
129 | connection_out = fd_out; | |
1e3b8b07 | 130 | cipher_init(&send_context, none, (u_char *) "", 0, NULL, 0); |
131 | cipher_init(&receive_context, none, (u_char *) "", 0, NULL, 0); | |
08dcb5d7 | 132 | newkeys[MODE_IN] = newkeys[MODE_OUT] = NULL; |
5260325f | 133 | if (!initialized) { |
134 | initialized = 1; | |
135 | buffer_init(&input); | |
136 | buffer_init(&output); | |
137 | buffer_init(&outgoing_packet); | |
138 | buffer_init(&incoming_packet); | |
139 | } | |
140 | /* Kludge: arrange the close function to be called from fatal(). */ | |
141 | fatal_add_cleanup((void (*) (void *)) packet_close, NULL); | |
8efc0c15 | 142 | } |
143 | ||
48e671d5 | 144 | /* Returns 1 if remote host is connected via socket, 0 if not. */ |
145 | ||
146 | int | |
147 | packet_connection_is_on_socket() | |
148 | { | |
149 | struct sockaddr_storage from, to; | |
150 | socklen_t fromlen, tolen; | |
151 | ||
152 | /* filedescriptors in and out are the same, so it's a socket */ | |
153 | if (connection_in == connection_out) | |
154 | return 1; | |
155 | fromlen = sizeof(from); | |
156 | memset(&from, 0, sizeof(from)); | |
9bc5ddfe | 157 | if (getpeername(connection_in, (struct sockaddr *)&from, &fromlen) < 0) |
48e671d5 | 158 | return 0; |
159 | tolen = sizeof(to); | |
160 | memset(&to, 0, sizeof(to)); | |
9bc5ddfe | 161 | if (getpeername(connection_out, (struct sockaddr *)&to, &tolen) < 0) |
48e671d5 | 162 | return 0; |
163 | if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0) | |
164 | return 0; | |
165 | if (from.ss_family != AF_INET && from.ss_family != AF_INET6) | |
166 | return 0; | |
167 | return 1; | |
168 | } | |
169 | ||
170 | /* returns 1 if connection is via ipv4 */ | |
171 | ||
172 | int | |
173 | packet_connection_is_ipv4() | |
174 | { | |
175 | struct sockaddr_storage to; | |
d45317d8 | 176 | socklen_t tolen = sizeof(to); |
48e671d5 | 177 | |
178 | memset(&to, 0, sizeof(to)); | |
179 | if (getsockname(connection_out, (struct sockaddr *)&to, &tolen) < 0) | |
180 | return 0; | |
181 | if (to.ss_family != AF_INET) | |
182 | return 0; | |
183 | return 1; | |
184 | } | |
185 | ||
8efc0c15 | 186 | /* Sets the connection into non-blocking mode. */ |
187 | ||
188 | void | |
189 | packet_set_nonblocking() | |
190 | { | |
5260325f | 191 | /* Set the socket into non-blocking mode. */ |
192 | if (fcntl(connection_in, F_SETFL, O_NONBLOCK) < 0) | |
193 | error("fcntl O_NONBLOCK: %.100s", strerror(errno)); | |
8efc0c15 | 194 | |
5260325f | 195 | if (connection_out != connection_in) { |
196 | if (fcntl(connection_out, F_SETFL, O_NONBLOCK) < 0) | |
197 | error("fcntl O_NONBLOCK: %.100s", strerror(errno)); | |
198 | } | |
8efc0c15 | 199 | } |
200 | ||
201 | /* Returns the socket used for reading. */ | |
202 | ||
203 | int | |
204 | packet_get_connection_in() | |
205 | { | |
5260325f | 206 | return connection_in; |
8efc0c15 | 207 | } |
208 | ||
209 | /* Returns the descriptor used for writing. */ | |
210 | ||
211 | int | |
212 | packet_get_connection_out() | |
213 | { | |
5260325f | 214 | return connection_out; |
8efc0c15 | 215 | } |
216 | ||
217 | /* Closes the connection and clears and frees internal data structures. */ | |
218 | ||
219 | void | |
220 | packet_close() | |
221 | { | |
5260325f | 222 | if (!initialized) |
223 | return; | |
224 | initialized = 0; | |
225 | if (connection_in == connection_out) { | |
226 | shutdown(connection_out, SHUT_RDWR); | |
227 | close(connection_out); | |
228 | } else { | |
229 | close(connection_in); | |
230 | close(connection_out); | |
231 | } | |
232 | buffer_free(&input); | |
233 | buffer_free(&output); | |
234 | buffer_free(&outgoing_packet); | |
235 | buffer_free(&incoming_packet); | |
6ba22c93 | 236 | if (compression_buffer_ready) { |
5260325f | 237 | buffer_free(&compression_buffer); |
238 | buffer_compress_uninit(); | |
239 | } | |
8efc0c15 | 240 | } |
241 | ||
242 | /* Sets remote side protocol flags. */ | |
243 | ||
244 | void | |
1e3b8b07 | 245 | packet_set_protocol_flags(u_int protocol_flags) |
8efc0c15 | 246 | { |
5260325f | 247 | remote_protocol_flags = protocol_flags; |
8efc0c15 | 248 | } |
249 | ||
250 | /* Returns the remote protocol flags set earlier by the above function. */ | |
251 | ||
1e3b8b07 | 252 | u_int |
8efc0c15 | 253 | packet_get_protocol_flags() |
254 | { | |
5260325f | 255 | return remote_protocol_flags; |
8efc0c15 | 256 | } |
257 | ||
aa3378df | 258 | /* |
259 | * Starts packet compression from the next packet on in both directions. | |
260 | * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip. | |
261 | */ | |
8efc0c15 | 262 | |
6ba22c93 | 263 | void |
264 | packet_init_compression() | |
265 | { | |
266 | if (compression_buffer_ready == 1) | |
267 | return; | |
268 | compression_buffer_ready = 1; | |
269 | buffer_init(&compression_buffer); | |
270 | } | |
271 | ||
8efc0c15 | 272 | void |
273 | packet_start_compression(int level) | |
274 | { | |
08dcb5d7 | 275 | if (packet_compression && !compat20) |
5260325f | 276 | fatal("Compression already enabled."); |
277 | packet_compression = 1; | |
6ba22c93 | 278 | packet_init_compression(); |
279 | buffer_compress_init_send(level); | |
280 | buffer_compress_init_recv(); | |
8efc0c15 | 281 | } |
282 | ||
aa3378df | 283 | /* |
284 | * Causes any further packets to be encrypted using the given key. The same | |
285 | * key is used for both sending and reception. However, both directions are | |
286 | * encrypted independently of each other. | |
287 | */ | |
8efc0c15 | 288 | void |
1e3b8b07 | 289 | packet_set_encryption_key(const u_char *key, u_int keylen, |
94ec8c6b | 290 | int number) |
8efc0c15 | 291 | { |
94ec8c6b | 292 | Cipher *cipher = cipher_by_number(number); |
293 | if (cipher == NULL) | |
294 | fatal("packet_set_encryption_key: unknown cipher number %d", number); | |
7e7327a1 | 295 | if (keylen < 20) |
94ec8c6b | 296 | fatal("packet_set_encryption_key: keylen too small: %d", keylen); |
297 | cipher_init(&receive_context, cipher, key, keylen, NULL, 0); | |
298 | cipher_init(&send_context, cipher, key, keylen, NULL, 0); | |
8efc0c15 | 299 | } |
300 | ||
08dcb5d7 | 301 | /* Start constructing a packet to send. */ |
8efc0c15 | 302 | void |
08dcb5d7 | 303 | packet_start(u_char type) |
8efc0c15 | 304 | { |
08dcb5d7 | 305 | u_char buf[9]; |
306 | int len; | |
7e7327a1 | 307 | |
12bf85ed | 308 | DBG(debug("packet_start[%d]", type)); |
08dcb5d7 | 309 | len = compat20 ? 6 : 9; |
310 | memset(buf, 0, len - 1); | |
311 | buf[len - 1] = type; | |
312 | buffer_clear(&outgoing_packet); | |
313 | buffer_append(&outgoing_packet, buf, len); | |
7e7327a1 | 314 | } |
315 | ||
08dcb5d7 | 316 | /* Append payload. */ |
8efc0c15 | 317 | void |
318 | packet_put_char(int value) | |
319 | { | |
5260325f | 320 | char ch = value; |
321 | buffer_append(&outgoing_packet, &ch, 1); | |
8efc0c15 | 322 | } |
8efc0c15 | 323 | void |
1e3b8b07 | 324 | packet_put_int(u_int value) |
8efc0c15 | 325 | { |
5260325f | 326 | buffer_put_int(&outgoing_packet, value); |
8efc0c15 | 327 | } |
8efc0c15 | 328 | void |
1e3b8b07 | 329 | packet_put_string(const char *buf, u_int len) |
8efc0c15 | 330 | { |
5260325f | 331 | buffer_put_string(&outgoing_packet, buf, len); |
8efc0c15 | 332 | } |
7e7327a1 | 333 | void |
334 | packet_put_cstring(const char *str) | |
335 | { | |
449c5ba5 | 336 | buffer_put_cstring(&outgoing_packet, str); |
7e7327a1 | 337 | } |
7e7327a1 | 338 | void |
1e3b8b07 | 339 | packet_put_raw(const char *buf, u_int len) |
7e7327a1 | 340 | { |
341 | buffer_append(&outgoing_packet, buf, len); | |
342 | } | |
8efc0c15 | 343 | void |
5260325f | 344 | packet_put_bignum(BIGNUM * value) |
8efc0c15 | 345 | { |
5260325f | 346 | buffer_put_bignum(&outgoing_packet, value); |
8efc0c15 | 347 | } |
7e7327a1 | 348 | void |
349 | packet_put_bignum2(BIGNUM * value) | |
350 | { | |
351 | buffer_put_bignum2(&outgoing_packet, value); | |
352 | } | |
8efc0c15 | 353 | |
aa3378df | 354 | /* |
355 | * Finalizes and sends the packet. If the encryption key has been set, | |
356 | * encrypts the packet before sending. | |
357 | */ | |
5260325f | 358 | |
8efc0c15 | 359 | void |
5ca51e19 | 360 | packet_send1(void) |
8efc0c15 | 361 | { |
5260325f | 362 | char buf[8], *cp; |
363 | int i, padding, len; | |
1e3b8b07 | 364 | u_int checksum; |
5260325f | 365 | u_int32_t rand = 0; |
366 | ||
aa3378df | 367 | /* |
368 | * If using packet compression, compress the payload of the outgoing | |
369 | * packet. | |
370 | */ | |
5260325f | 371 | if (packet_compression) { |
372 | buffer_clear(&compression_buffer); | |
373 | /* Skip padding. */ | |
374 | buffer_consume(&outgoing_packet, 8); | |
375 | /* padding */ | |
376 | buffer_append(&compression_buffer, "\0\0\0\0\0\0\0\0", 8); | |
377 | buffer_compress(&outgoing_packet, &compression_buffer); | |
378 | buffer_clear(&outgoing_packet); | |
379 | buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer), | |
380 | buffer_len(&compression_buffer)); | |
381 | } | |
382 | /* Compute packet length without padding (add checksum, remove padding). */ | |
383 | len = buffer_len(&outgoing_packet) + 4 - 8; | |
384 | ||
1d1ffb87 | 385 | /* Insert padding. Initialized to zero in packet_start1() */ |
5260325f | 386 | padding = 8 - len % 8; |
08dcb5d7 | 387 | if (send_context.cipher->number != SSH_CIPHER_NONE) { |
5260325f | 388 | cp = buffer_ptr(&outgoing_packet); |
389 | for (i = 0; i < padding; i++) { | |
390 | if (i % 4 == 0) | |
391 | rand = arc4random(); | |
392 | cp[7 - i] = rand & 0xff; | |
393 | rand >>= 8; | |
394 | } | |
395 | } | |
396 | buffer_consume(&outgoing_packet, 8 - padding); | |
397 | ||
398 | /* Add check bytes. */ | |
1e3b8b07 | 399 | checksum = ssh_crc32((u_char *) buffer_ptr(&outgoing_packet), |
2e73a022 | 400 | buffer_len(&outgoing_packet)); |
5260325f | 401 | PUT_32BIT(buf, checksum); |
402 | buffer_append(&outgoing_packet, buf, 4); | |
8efc0c15 | 403 | |
404 | #ifdef PACKET_DEBUG | |
5260325f | 405 | fprintf(stderr, "packet_send plain: "); |
406 | buffer_dump(&outgoing_packet); | |
8efc0c15 | 407 | #endif |
408 | ||
5260325f | 409 | /* Append to output. */ |
410 | PUT_32BIT(buf, len); | |
411 | buffer_append(&output, buf, 4); | |
412 | buffer_append_space(&output, &cp, buffer_len(&outgoing_packet)); | |
08dcb5d7 | 413 | cipher_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet), |
5260325f | 414 | buffer_len(&outgoing_packet)); |
415 | ||
8efc0c15 | 416 | #ifdef PACKET_DEBUG |
5260325f | 417 | fprintf(stderr, "encrypted: "); |
418 | buffer_dump(&output); | |
8efc0c15 | 419 | #endif |
420 | ||
5260325f | 421 | buffer_clear(&outgoing_packet); |
8efc0c15 | 422 | |
aa3378df | 423 | /* |
424 | * Note that the packet is now only buffered in output. It won\'t be | |
425 | * actually sent until packet_write_wait or packet_write_poll is | |
426 | * called. | |
427 | */ | |
8efc0c15 | 428 | } |
429 | ||
d1ac6175 | 430 | void |
431 | set_newkeys(int mode) | |
432 | { | |
433 | Enc *enc; | |
434 | Mac *mac; | |
435 | Comp *comp; | |
436 | CipherContext *cc; | |
437 | ||
438 | debug("newkeys: mode %d", mode); | |
439 | ||
440 | cc = (mode == MODE_OUT) ? &send_context : &receive_context; | |
441 | if (newkeys[mode] != NULL) { | |
442 | debug("newkeys: rekeying"); | |
d8ee838b | 443 | /* todo: free old keys, reset compression/cipher-ctxt; */ |
a7ca6275 | 444 | memset(cc, 0, sizeof(*cc)); |
445 | enc = &newkeys[mode]->enc; | |
446 | mac = &newkeys[mode]->mac; | |
447 | comp = &newkeys[mode]->comp; | |
cd332296 | 448 | memset(mac->key, 0, mac->key_len); |
a7ca6275 | 449 | xfree(enc->name); |
450 | xfree(enc->iv); | |
451 | xfree(enc->key); | |
452 | xfree(mac->name); | |
453 | xfree(mac->key); | |
454 | xfree(comp->name); | |
d8ee838b | 455 | xfree(newkeys[mode]); |
d1ac6175 | 456 | } |
457 | newkeys[mode] = kex_get_newkeys(mode); | |
458 | if (newkeys[mode] == NULL) | |
459 | fatal("newkeys: no keys for mode %d", mode); | |
460 | enc = &newkeys[mode]->enc; | |
461 | mac = &newkeys[mode]->mac; | |
462 | comp = &newkeys[mode]->comp; | |
463 | if (mac->md != NULL) | |
464 | mac->enabled = 1; | |
465 | DBG(debug("cipher_init_context: %d", mode)); | |
466 | cipher_init(cc, enc->cipher, enc->key, enc->cipher->key_len, | |
467 | enc->iv, enc->cipher->block_size); | |
a7ca6275 | 468 | memset(enc->iv, 0, enc->cipher->block_size); |
469 | memset(enc->key, 0, enc->cipher->key_len); | |
d1ac6175 | 470 | if (comp->type != 0 && comp->enabled == 0) { |
6ba22c93 | 471 | packet_init_compression(); |
472 | if (mode == MODE_OUT) | |
473 | buffer_compress_init_send(6); | |
474 | else | |
475 | buffer_compress_init_recv(); | |
d1ac6175 | 476 | comp->enabled = 1; |
d1ac6175 | 477 | } |
478 | } | |
479 | ||
7e7327a1 | 480 | /* |
481 | * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue) | |
482 | */ | |
483 | void | |
5ca51e19 | 484 | packet_send2(void) |
7e7327a1 | 485 | { |
b2552997 | 486 | static u_int32_t seqnr = 0; |
08dcb5d7 | 487 | u_char type, *ucp, *macbuf = NULL; |
7e7327a1 | 488 | char *cp; |
1e3b8b07 | 489 | u_int packet_length = 0; |
490 | u_int i, padlen, len; | |
7e7327a1 | 491 | u_int32_t rand = 0; |
7e7327a1 | 492 | Enc *enc = NULL; |
493 | Mac *mac = NULL; | |
494 | Comp *comp = NULL; | |
495 | int block_size; | |
496 | ||
d1ac6175 | 497 | if (newkeys[MODE_OUT] != NULL) { |
498 | enc = &newkeys[MODE_OUT]->enc; | |
499 | mac = &newkeys[MODE_OUT]->mac; | |
500 | comp = &newkeys[MODE_OUT]->comp; | |
7e7327a1 | 501 | } |
94ec8c6b | 502 | block_size = enc ? enc->cipher->block_size : 8; |
7e7327a1 | 503 | |
08dcb5d7 | 504 | ucp = (u_char *) buffer_ptr(&outgoing_packet); |
505 | type = ucp[5]; | |
7e7327a1 | 506 | |
507 | #ifdef PACKET_DEBUG | |
508 | fprintf(stderr, "plain: "); | |
509 | buffer_dump(&outgoing_packet); | |
510 | #endif | |
511 | ||
512 | if (comp && comp->enabled) { | |
513 | len = buffer_len(&outgoing_packet); | |
514 | /* skip header, compress only payload */ | |
515 | buffer_consume(&outgoing_packet, 5); | |
516 | buffer_clear(&compression_buffer); | |
517 | buffer_compress(&outgoing_packet, &compression_buffer); | |
518 | buffer_clear(&outgoing_packet); | |
519 | buffer_append(&outgoing_packet, "\0\0\0\0\0", 5); | |
520 | buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer), | |
521 | buffer_len(&compression_buffer)); | |
522 | DBG(debug("compression: raw %d compressed %d", len, | |
523 | buffer_len(&outgoing_packet))); | |
524 | } | |
525 | ||
526 | /* sizeof (packet_len + pad_len + payload) */ | |
527 | len = buffer_len(&outgoing_packet); | |
528 | ||
529 | /* | |
530 | * calc size of padding, alloc space, get random data, | |
531 | * minimum padding is 4 bytes | |
532 | */ | |
533 | padlen = block_size - (len % block_size); | |
534 | if (padlen < 4) | |
535 | padlen += block_size; | |
536 | buffer_append_space(&outgoing_packet, &cp, padlen); | |
94ec8c6b | 537 | if (enc && enc->cipher->number != SSH_CIPHER_NONE) { |
1d1ffb87 | 538 | /* random padding */ |
7e7327a1 | 539 | for (i = 0; i < padlen; i++) { |
540 | if (i % 4 == 0) | |
541 | rand = arc4random(); | |
542 | cp[i] = rand & 0xff; | |
6e18cb71 | 543 | rand >>= 8; |
7e7327a1 | 544 | } |
1d1ffb87 | 545 | } else { |
546 | /* clear padding */ | |
547 | memset(cp, 0, padlen); | |
7e7327a1 | 548 | } |
549 | /* packet_length includes payload, padding and padding length field */ | |
550 | packet_length = buffer_len(&outgoing_packet) - 4; | |
08dcb5d7 | 551 | ucp = (u_char *)buffer_ptr(&outgoing_packet); |
552 | PUT_32BIT(ucp, packet_length); | |
553 | ucp[4] = padlen; | |
7e7327a1 | 554 | DBG(debug("send: len %d (includes padlen %d)", packet_length+4, padlen)); |
555 | ||
556 | /* compute MAC over seqnr and packet(length fields, payload, padding) */ | |
557 | if (mac && mac->enabled) { | |
b2552997 | 558 | macbuf = mac_compute(mac, seqnr, |
1e3b8b07 | 559 | (u_char *) buffer_ptr(&outgoing_packet), |
b2552997 | 560 | buffer_len(&outgoing_packet)); |
94ec8c6b | 561 | DBG(debug("done calc MAC out #%d", seqnr)); |
7e7327a1 | 562 | } |
563 | /* encrypt packet and append to output buffer. */ | |
564 | buffer_append_space(&output, &cp, buffer_len(&outgoing_packet)); | |
08dcb5d7 | 565 | cipher_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet), |
7e7327a1 | 566 | buffer_len(&outgoing_packet)); |
567 | /* append unencrypted MAC */ | |
568 | if (mac && mac->enabled) | |
569 | buffer_append(&output, (char *)macbuf, mac->mac_len); | |
570 | #ifdef PACKET_DEBUG | |
571 | fprintf(stderr, "encrypted: "); | |
572 | buffer_dump(&output); | |
573 | #endif | |
6ae2364d | 574 | /* increment sequence number for outgoing packets */ |
575 | if (++seqnr == 0) | |
576 | log("outgoing seqnr wraps around"); | |
7e7327a1 | 577 | buffer_clear(&outgoing_packet); |
578 | ||
d1ac6175 | 579 | if (type == SSH2_MSG_NEWKEYS) |
580 | set_newkeys(MODE_OUT); | |
7e7327a1 | 581 | } |
582 | ||
583 | void | |
584 | packet_send() | |
585 | { | |
08dcb5d7 | 586 | if (compat20) |
7e7327a1 | 587 | packet_send2(); |
588 | else | |
589 | packet_send1(); | |
590 | DBG(debug("packet_send done")); | |
591 | } | |
592 | ||
aa3378df | 593 | /* |
594 | * Waits until a packet has been received, and returns its type. Note that | |
595 | * no other data is processed until this returns, so this function should not | |
596 | * be used during the interactive session. | |
597 | */ | |
8efc0c15 | 598 | |
599 | int | |
600 | packet_read(int *payload_len_ptr) | |
601 | { | |
5260325f | 602 | int type, len; |
20e04e90 | 603 | fd_set *setp; |
5260325f | 604 | char buf[8192]; |
7e7327a1 | 605 | DBG(debug("packet_read()")); |
5260325f | 606 | |
20e04e90 | 607 | setp = (fd_set *)xmalloc(howmany(connection_in+1, NFDBITS) * |
608 | sizeof(fd_mask)); | |
609 | ||
5260325f | 610 | /* Since we are blocking, ensure that all written packets have been sent. */ |
611 | packet_write_wait(); | |
612 | ||
613 | /* Stay in the loop until we have received a complete packet. */ | |
614 | for (;;) { | |
615 | /* Try to read a packet from the buffer. */ | |
616 | type = packet_read_poll(payload_len_ptr); | |
08dcb5d7 | 617 | if (!compat20 && ( |
1d1ffb87 | 618 | type == SSH_SMSG_SUCCESS |
5260325f | 619 | || type == SSH_SMSG_FAILURE |
620 | || type == SSH_CMSG_EOF | |
1d1ffb87 | 621 | || type == SSH_CMSG_EXIT_CONFIRMATION)) |
5260325f | 622 | packet_integrity_check(*payload_len_ptr, 0, type); |
623 | /* If we got a packet, return it. */ | |
20e04e90 | 624 | if (type != SSH_MSG_NONE) { |
625 | xfree(setp); | |
5260325f | 626 | return type; |
20e04e90 | 627 | } |
aa3378df | 628 | /* |
629 | * Otherwise, wait for some data to arrive, add it to the | |
630 | * buffer, and try again. | |
631 | */ | |
20e04e90 | 632 | memset(setp, 0, howmany(connection_in + 1, NFDBITS) * |
633 | sizeof(fd_mask)); | |
634 | FD_SET(connection_in, setp); | |
aa3378df | 635 | |
5260325f | 636 | /* Wait for some data to arrive. */ |
20e04e90 | 637 | while (select(connection_in + 1, setp, NULL, NULL, NULL) == -1 && |
fd193ca4 | 638 | (errno == EAGAIN || errno == EINTR)) |
639 | ; | |
aa3378df | 640 | |
5260325f | 641 | /* Read data from the socket. */ |
642 | len = read(connection_in, buf, sizeof(buf)); | |
89cafde6 | 643 | if (len == 0) { |
644 | log("Connection closed by %.200s", get_remote_ipaddr()); | |
645 | fatal_cleanup(); | |
646 | } | |
5260325f | 647 | if (len < 0) |
648 | fatal("Read from socket failed: %.100s", strerror(errno)); | |
649 | /* Append it to the buffer. */ | |
650 | packet_process_incoming(buf, len); | |
651 | } | |
652 | /* NOTREACHED */ | |
8efc0c15 | 653 | } |
654 | ||
aa3378df | 655 | /* |
656 | * Waits until a packet has been received, verifies that its type matches | |
657 | * that given, and gives a fatal error and exits if there is a mismatch. | |
658 | */ | |
8efc0c15 | 659 | |
660 | void | |
661 | packet_read_expect(int *payload_len_ptr, int expected_type) | |
662 | { | |
5260325f | 663 | int type; |
8efc0c15 | 664 | |
5260325f | 665 | type = packet_read(payload_len_ptr); |
666 | if (type != expected_type) | |
667 | packet_disconnect("Protocol error: expected packet type %d, got %d", | |
7e7327a1 | 668 | expected_type, type); |
8efc0c15 | 669 | } |
670 | ||
671 | /* Checks if a full packet is available in the data received so far via | |
5260325f | 672 | * packet_process_incoming. If so, reads the packet; otherwise returns |
673 | * SSH_MSG_NONE. This does not wait for data from the connection. | |
674 | * | |
675 | * SSH_MSG_DISCONNECT is handled specially here. Also, | |
676 | * SSH_MSG_IGNORE messages are skipped by this function and are never returned | |
677 | * to higher levels. | |
678 | * | |
679 | * The returned payload_len does include space consumed by: | |
680 | * Packet length | |
681 | * Padding | |
682 | * Packet type | |
683 | * Check bytes | |
684 | */ | |
8efc0c15 | 685 | |
686 | int | |
7e7327a1 | 687 | packet_read_poll1(int *payload_len_ptr) |
8efc0c15 | 688 | { |
1e3b8b07 | 689 | u_int len, padded_len; |
08dcb5d7 | 690 | u_char *ucp, type; |
691 | char *cp; | |
1e3b8b07 | 692 | u_int checksum, stored_checksum; |
5260325f | 693 | |
5260325f | 694 | /* Check if input size is less than minimum packet size. */ |
695 | if (buffer_len(&input) < 4 + 8) | |
696 | return SSH_MSG_NONE; | |
697 | /* Get length of incoming packet. */ | |
1e3b8b07 | 698 | ucp = (u_char *) buffer_ptr(&input); |
5260325f | 699 | len = GET_32BIT(ucp); |
700 | if (len < 1 + 2 + 2 || len > 256 * 1024) | |
701 | packet_disconnect("Bad packet length %d.", len); | |
702 | padded_len = (len + 8) & ~7; | |
703 | ||
704 | /* Check if the packet has been entirely received. */ | |
705 | if (buffer_len(&input) < 4 + padded_len) | |
706 | return SSH_MSG_NONE; | |
707 | ||
708 | /* The entire packet is in buffer. */ | |
709 | ||
710 | /* Consume packet length. */ | |
711 | buffer_consume(&input, 4); | |
712 | ||
08dcb5d7 | 713 | /* |
714 | * Cryptographic attack detector for ssh | |
715 | * (C)1998 CORE-SDI, Buenos Aires Argentina | |
716 | * Ariel Futoransky(futo@core-sdi.com) | |
717 | */ | |
718 | if (receive_context.cipher->number != SSH_CIPHER_NONE && | |
719 | detect_attack(buffer_ptr(&input), padded_len, NULL) == DEATTACK_DETECTED) | |
720 | packet_disconnect("crc32 compensation attack: network attack detected"); | |
721 | ||
722 | /* Decrypt data to incoming_packet. */ | |
5260325f | 723 | buffer_clear(&incoming_packet); |
724 | buffer_append_space(&incoming_packet, &cp, padded_len); | |
08dcb5d7 | 725 | cipher_decrypt(&receive_context, cp, buffer_ptr(&input), padded_len); |
726 | ||
5260325f | 727 | buffer_consume(&input, padded_len); |
8efc0c15 | 728 | |
729 | #ifdef PACKET_DEBUG | |
5260325f | 730 | fprintf(stderr, "read_poll plain: "); |
731 | buffer_dump(&incoming_packet); | |
8efc0c15 | 732 | #endif |
5260325f | 733 | |
734 | /* Compute packet checksum. */ | |
1e3b8b07 | 735 | checksum = ssh_crc32((u_char *) buffer_ptr(&incoming_packet), |
7e7327a1 | 736 | buffer_len(&incoming_packet) - 4); |
5260325f | 737 | |
738 | /* Skip padding. */ | |
739 | buffer_consume(&incoming_packet, 8 - len % 8); | |
740 | ||
741 | /* Test check bytes. */ | |
5260325f | 742 | if (len != buffer_len(&incoming_packet)) |
743 | packet_disconnect("packet_read_poll: len %d != buffer_len %d.", | |
7e7327a1 | 744 | len, buffer_len(&incoming_packet)); |
5260325f | 745 | |
1e3b8b07 | 746 | ucp = (u_char *) buffer_ptr(&incoming_packet) + len - 4; |
5260325f | 747 | stored_checksum = GET_32BIT(ucp); |
748 | if (checksum != stored_checksum) | |
749 | packet_disconnect("Corrupted check bytes on input."); | |
750 | buffer_consume_end(&incoming_packet, 4); | |
751 | ||
5260325f | 752 | if (packet_compression) { |
753 | buffer_clear(&compression_buffer); | |
754 | buffer_uncompress(&incoming_packet, &compression_buffer); | |
755 | buffer_clear(&incoming_packet); | |
756 | buffer_append(&incoming_packet, buffer_ptr(&compression_buffer), | |
7e7327a1 | 757 | buffer_len(&compression_buffer)); |
5260325f | 758 | } |
08dcb5d7 | 759 | type = buffer_get_char(&incoming_packet); |
5260325f | 760 | *payload_len_ptr = buffer_len(&incoming_packet); |
08dcb5d7 | 761 | return type; |
5260325f | 762 | } |
763 | ||
7e7327a1 | 764 | int |
765 | packet_read_poll2(int *payload_len_ptr) | |
766 | { | |
b2552997 | 767 | static u_int32_t seqnr = 0; |
768 | static u_int packet_length = 0; | |
1e3b8b07 | 769 | u_int padlen, need; |
08dcb5d7 | 770 | u_char *macbuf, *ucp, type; |
7e7327a1 | 771 | char *cp; |
7e7327a1 | 772 | int maclen, block_size; |
773 | Enc *enc = NULL; | |
774 | Mac *mac = NULL; | |
775 | Comp *comp = NULL; | |
776 | ||
d1ac6175 | 777 | if (newkeys[MODE_IN] != NULL) { |
778 | enc = &newkeys[MODE_IN]->enc; | |
779 | mac = &newkeys[MODE_IN]->mac; | |
780 | comp = &newkeys[MODE_IN]->comp; | |
7e7327a1 | 781 | } |
782 | maclen = mac && mac->enabled ? mac->mac_len : 0; | |
94ec8c6b | 783 | block_size = enc ? enc->cipher->block_size : 8; |
7e7327a1 | 784 | |
785 | if (packet_length == 0) { | |
786 | /* | |
787 | * check if input size is less than the cipher block size, | |
788 | * decrypt first block and extract length of incoming packet | |
789 | */ | |
790 | if (buffer_len(&input) < block_size) | |
791 | return SSH_MSG_NONE; | |
792 | buffer_clear(&incoming_packet); | |
793 | buffer_append_space(&incoming_packet, &cp, block_size); | |
08dcb5d7 | 794 | cipher_decrypt(&receive_context, cp, buffer_ptr(&input), |
7e7327a1 | 795 | block_size); |
1e3b8b07 | 796 | ucp = (u_char *) buffer_ptr(&incoming_packet); |
7e7327a1 | 797 | packet_length = GET_32BIT(ucp); |
798 | if (packet_length < 1 + 4 || packet_length > 256 * 1024) { | |
799 | buffer_dump(&incoming_packet); | |
800 | packet_disconnect("Bad packet length %d.", packet_length); | |
801 | } | |
802 | DBG(debug("input: packet len %d", packet_length+4)); | |
803 | buffer_consume(&input, block_size); | |
804 | } | |
805 | /* we have a partial packet of block_size bytes */ | |
806 | need = 4 + packet_length - block_size; | |
807 | DBG(debug("partial packet %d, need %d, maclen %d", block_size, | |
808 | need, maclen)); | |
809 | if (need % block_size != 0) | |
810 | fatal("padding error: need %d block %d mod %d", | |
811 | need, block_size, need % block_size); | |
812 | /* | |
813 | * check if the entire packet has been received and | |
814 | * decrypt into incoming_packet | |
815 | */ | |
816 | if (buffer_len(&input) < need + maclen) | |
817 | return SSH_MSG_NONE; | |
818 | #ifdef PACKET_DEBUG | |
819 | fprintf(stderr, "read_poll enc/full: "); | |
820 | buffer_dump(&input); | |
821 | #endif | |
822 | buffer_append_space(&incoming_packet, &cp, need); | |
08dcb5d7 | 823 | cipher_decrypt(&receive_context, cp, buffer_ptr(&input), need); |
7e7327a1 | 824 | buffer_consume(&input, need); |
825 | /* | |
826 | * compute MAC over seqnr and packet, | |
827 | * increment sequence number for incoming packet | |
828 | */ | |
6ae2364d | 829 | if (mac && mac->enabled) { |
b2552997 | 830 | macbuf = mac_compute(mac, seqnr, |
1e3b8b07 | 831 | (u_char *) buffer_ptr(&incoming_packet), |
b2552997 | 832 | buffer_len(&incoming_packet)); |
7e7327a1 | 833 | if (memcmp(macbuf, buffer_ptr(&input), mac->mac_len) != 0) |
94ec8c6b | 834 | packet_disconnect("Corrupted MAC on input."); |
835 | DBG(debug("MAC #%d ok", seqnr)); | |
7e7327a1 | 836 | buffer_consume(&input, mac->mac_len); |
837 | } | |
6ae2364d | 838 | if (++seqnr == 0) |
839 | log("incoming seqnr wraps around"); | |
7e7327a1 | 840 | |
841 | /* get padlen */ | |
842 | cp = buffer_ptr(&incoming_packet) + 4; | |
08dcb5d7 | 843 | padlen = (u_char) *cp; |
7e7327a1 | 844 | DBG(debug("input: padlen %d", padlen)); |
845 | if (padlen < 4) | |
846 | packet_disconnect("Corrupted padlen %d on input.", padlen); | |
847 | ||
848 | /* skip packet size + padlen, discard padding */ | |
849 | buffer_consume(&incoming_packet, 4 + 1); | |
850 | buffer_consume_end(&incoming_packet, padlen); | |
851 | ||
852 | DBG(debug("input: len before de-compress %d", buffer_len(&incoming_packet))); | |
853 | if (comp && comp->enabled) { | |
854 | buffer_clear(&compression_buffer); | |
855 | buffer_uncompress(&incoming_packet, &compression_buffer); | |
856 | buffer_clear(&incoming_packet); | |
857 | buffer_append(&incoming_packet, buffer_ptr(&compression_buffer), | |
858 | buffer_len(&compression_buffer)); | |
859 | DBG(debug("input: len after de-compress %d", buffer_len(&incoming_packet))); | |
860 | } | |
861 | /* | |
862 | * get packet type, implies consume. | |
863 | * return length of payload (without type field) | |
864 | */ | |
08dcb5d7 | 865 | type = buffer_get_char(&incoming_packet); |
d1ac6175 | 866 | if (type == SSH2_MSG_NEWKEYS) |
867 | set_newkeys(MODE_IN); | |
08dcb5d7 | 868 | *payload_len_ptr = buffer_len(&incoming_packet); |
7e7327a1 | 869 | #ifdef PACKET_DEBUG |
12bf85ed | 870 | fprintf(stderr, "read/plain[%d]:\r\n", type); |
7e7327a1 | 871 | buffer_dump(&incoming_packet); |
872 | #endif | |
08dcb5d7 | 873 | /* reset for next packet */ |
874 | packet_length = 0; | |
875 | return type; | |
7e7327a1 | 876 | } |
877 | ||
878 | int | |
879 | packet_read_poll(int *payload_len_ptr) | |
880 | { | |
08dcb5d7 | 881 | int reason; |
882 | u_char type; | |
7e7327a1 | 883 | char *msg; |
7e7327a1 | 884 | |
08dcb5d7 | 885 | for (;;) { |
886 | if (compat20) { | |
887 | type = packet_read_poll2(payload_len_ptr); | |
888 | if (type) | |
7e7327a1 | 889 | DBG(debug("received packet type %d", type)); |
890 | switch(type) { | |
891 | case SSH2_MSG_IGNORE: | |
892 | break; | |
893 | case SSH2_MSG_DEBUG: | |
894 | packet_get_char(); | |
895 | msg = packet_get_string(NULL); | |
896 | debug("Remote: %.900s", msg); | |
897 | xfree(msg); | |
898 | msg = packet_get_string(NULL); | |
899 | xfree(msg); | |
900 | break; | |
901 | case SSH2_MSG_DISCONNECT: | |
902 | reason = packet_get_int(); | |
903 | msg = packet_get_string(NULL); | |
7c49df64 | 904 | log("Received disconnect from %s: %d: %.400s", get_remote_ipaddr(), |
905 | reason, msg); | |
7e7327a1 | 906 | xfree(msg); |
907 | fatal_cleanup(); | |
908 | break; | |
909 | default: | |
910 | return type; | |
911 | break; | |
2b87da3b | 912 | } |
7e7327a1 | 913 | } else { |
08dcb5d7 | 914 | type = packet_read_poll1(payload_len_ptr); |
7e7327a1 | 915 | switch(type) { |
916 | case SSH_MSG_IGNORE: | |
917 | break; | |
918 | case SSH_MSG_DEBUG: | |
919 | msg = packet_get_string(NULL); | |
920 | debug("Remote: %.900s", msg); | |
921 | xfree(msg); | |
922 | break; | |
923 | case SSH_MSG_DISCONNECT: | |
924 | msg = packet_get_string(NULL); | |
7c49df64 | 925 | log("Received disconnect from %s: %.400s", get_remote_ipaddr(), |
926 | msg); | |
7e7327a1 | 927 | fatal_cleanup(); |
928 | xfree(msg); | |
929 | break; | |
930 | default: | |
08dcb5d7 | 931 | if (type) |
7e7327a1 | 932 | DBG(debug("received packet type %d", type)); |
933 | return type; | |
934 | break; | |
2b87da3b | 935 | } |
7e7327a1 | 936 | } |
937 | } | |
938 | } | |
939 | ||
aa3378df | 940 | /* |
941 | * Buffers the given amount of input characters. This is intended to be used | |
942 | * together with packet_read_poll. | |
943 | */ | |
8efc0c15 | 944 | |
945 | void | |
1e3b8b07 | 946 | packet_process_incoming(const char *buf, u_int len) |
8efc0c15 | 947 | { |
5260325f | 948 | buffer_append(&input, buf, len); |
8efc0c15 | 949 | } |
950 | ||
951 | /* Returns a character from the packet. */ | |
952 | ||
1e3b8b07 | 953 | u_int |
8efc0c15 | 954 | packet_get_char() |
955 | { | |
5260325f | 956 | char ch; |
957 | buffer_get(&incoming_packet, &ch, 1); | |
1e3b8b07 | 958 | return (u_char) ch; |
8efc0c15 | 959 | } |
960 | ||
961 | /* Returns an integer from the packet data. */ | |
962 | ||
1e3b8b07 | 963 | u_int |
8efc0c15 | 964 | packet_get_int() |
965 | { | |
5260325f | 966 | return buffer_get_int(&incoming_packet); |
8efc0c15 | 967 | } |
968 | ||
aa3378df | 969 | /* |
970 | * Returns an arbitrary precision integer from the packet data. The integer | |
971 | * must have been initialized before this call. | |
972 | */ | |
8efc0c15 | 973 | |
974 | void | |
5260325f | 975 | packet_get_bignum(BIGNUM * value, int *length_ptr) |
8efc0c15 | 976 | { |
5260325f | 977 | *length_ptr = buffer_get_bignum(&incoming_packet, value); |
8efc0c15 | 978 | } |
979 | ||
7e7327a1 | 980 | void |
981 | packet_get_bignum2(BIGNUM * value, int *length_ptr) | |
982 | { | |
983 | *length_ptr = buffer_get_bignum2(&incoming_packet, value); | |
984 | } | |
985 | ||
986 | char * | |
987 | packet_get_raw(int *length_ptr) | |
988 | { | |
989 | int bytes = buffer_len(&incoming_packet); | |
990 | if (length_ptr != NULL) | |
991 | *length_ptr = bytes; | |
992 | return buffer_ptr(&incoming_packet); | |
993 | } | |
994 | ||
6ae2364d | 995 | int |
996 | packet_remaining(void) | |
997 | { | |
998 | return buffer_len(&incoming_packet); | |
999 | } | |
1000 | ||
aa3378df | 1001 | /* |
1002 | * Returns a string from the packet data. The string is allocated using | |
1003 | * xmalloc; it is the responsibility of the calling program to free it when | |
1004 | * no longer needed. The length_ptr argument may be NULL, or point to an | |
1005 | * integer into which the length of the string is stored. | |
1006 | */ | |
8efc0c15 | 1007 | |
aa3378df | 1008 | char * |
1e3b8b07 | 1009 | packet_get_string(u_int *length_ptr) |
8efc0c15 | 1010 | { |
5260325f | 1011 | return buffer_get_string(&incoming_packet, length_ptr); |
8efc0c15 | 1012 | } |
1013 | ||
aa3378df | 1014 | /* |
1015 | * Sends a diagnostic message from the server to the client. This message | |
1016 | * can be sent at any time (but not while constructing another message). The | |
1017 | * message is printed immediately, but only if the client is being executed | |
1018 | * in verbose mode. These messages are primarily intended to ease debugging | |
1019 | * authentication problems. The length of the formatted message must not | |
1020 | * exceed 1024 bytes. This will automatically call packet_write_wait. | |
1021 | */ | |
8efc0c15 | 1022 | |
1023 | void | |
5260325f | 1024 | packet_send_debug(const char *fmt,...) |
8efc0c15 | 1025 | { |
5260325f | 1026 | char buf[1024]; |
1027 | va_list args; | |
1028 | ||
f72fc97f | 1029 | if (compat20 && (datafellows & SSH_BUG_DEBUG)) |
1030 | return; | |
1031 | ||
5260325f | 1032 | va_start(args, fmt); |
1033 | vsnprintf(buf, sizeof(buf), fmt, args); | |
1034 | va_end(args); | |
1035 | ||
c4bc58eb | 1036 | if (compat20) { |
1037 | packet_start(SSH2_MSG_DEBUG); | |
1038 | packet_put_char(0); /* bool: always display */ | |
1039 | packet_put_cstring(buf); | |
1040 | packet_put_cstring(""); | |
1041 | } else { | |
1042 | packet_start(SSH_MSG_DEBUG); | |
1043 | packet_put_cstring(buf); | |
1044 | } | |
5260325f | 1045 | packet_send(); |
1046 | packet_write_wait(); | |
8efc0c15 | 1047 | } |
1048 | ||
aa3378df | 1049 | /* |
1050 | * Logs the error plus constructs and sends a disconnect packet, closes the | |
1051 | * connection, and exits. This function never returns. The error message | |
1052 | * should not contain a newline. The length of the formatted message must | |
1053 | * not exceed 1024 bytes. | |
1054 | */ | |
8efc0c15 | 1055 | |
1056 | void | |
5260325f | 1057 | packet_disconnect(const char *fmt,...) |
1058 | { | |
1059 | char buf[1024]; | |
1060 | va_list args; | |
1061 | static int disconnecting = 0; | |
1062 | if (disconnecting) /* Guard against recursive invocations. */ | |
1063 | fatal("packet_disconnect called recursively."); | |
1064 | disconnecting = 1; | |
1065 | ||
aa3378df | 1066 | /* |
1067 | * Format the message. Note that the caller must make sure the | |
1068 | * message is of limited size. | |
1069 | */ | |
5260325f | 1070 | va_start(args, fmt); |
1071 | vsnprintf(buf, sizeof(buf), fmt, args); | |
1072 | va_end(args); | |
1073 | ||
1074 | /* Send the disconnect message to the other side, and wait for it to get sent. */ | |
7e7327a1 | 1075 | if (compat20) { |
1076 | packet_start(SSH2_MSG_DISCONNECT); | |
1077 | packet_put_int(SSH2_DISCONNECT_PROTOCOL_ERROR); | |
1078 | packet_put_cstring(buf); | |
1079 | packet_put_cstring(""); | |
1080 | } else { | |
1081 | packet_start(SSH_MSG_DISCONNECT); | |
449c5ba5 | 1082 | packet_put_cstring(buf); |
7e7327a1 | 1083 | } |
5260325f | 1084 | packet_send(); |
1085 | packet_write_wait(); | |
1086 | ||
1087 | /* Stop listening for connections. */ | |
1088 | channel_stop_listening(); | |
1089 | ||
1090 | /* Close the connection. */ | |
1091 | packet_close(); | |
1092 | ||
1093 | /* Display the error locally and exit. */ | |
57112b5a | 1094 | log("Disconnecting: %.100s", buf); |
1095 | fatal_cleanup(); | |
8efc0c15 | 1096 | } |
1097 | ||
aa3378df | 1098 | /* Checks if there is any buffered output, and tries to write some of the output. */ |
8efc0c15 | 1099 | |
1100 | void | |
1101 | packet_write_poll() | |
1102 | { | |
5260325f | 1103 | int len = buffer_len(&output); |
1104 | if (len > 0) { | |
1105 | len = write(connection_out, buffer_ptr(&output), len); | |
1106 | if (len <= 0) { | |
1107 | if (errno == EAGAIN) | |
1108 | return; | |
1109 | else | |
1110 | fatal("Write failed: %.100s", strerror(errno)); | |
1111 | } | |
1112 | buffer_consume(&output, len); | |
1113 | } | |
8efc0c15 | 1114 | } |
1115 | ||
aa3378df | 1116 | /* |
1117 | * Calls packet_write_poll repeatedly until all pending output data has been | |
1118 | * written. | |
1119 | */ | |
8efc0c15 | 1120 | |
1121 | void | |
1122 | packet_write_wait() | |
1123 | { | |
20e04e90 | 1124 | fd_set *setp; |
1125 | ||
1126 | setp = (fd_set *)xmalloc(howmany(connection_out + 1, NFDBITS) * | |
1127 | sizeof(fd_mask)); | |
5260325f | 1128 | packet_write_poll(); |
1129 | while (packet_have_data_to_write()) { | |
20e04e90 | 1130 | memset(setp, 0, howmany(connection_out + 1, NFDBITS) * |
1131 | sizeof(fd_mask)); | |
1132 | FD_SET(connection_out, setp); | |
1133 | while (select(connection_out + 1, NULL, setp, NULL, NULL) == -1 && | |
fd193ca4 | 1134 | (errno == EAGAIN || errno == EINTR)) |
1135 | ; | |
5260325f | 1136 | packet_write_poll(); |
1137 | } | |
20e04e90 | 1138 | xfree(setp); |
8efc0c15 | 1139 | } |
1140 | ||
1141 | /* Returns true if there is buffered data to write to the connection. */ | |
1142 | ||
1143 | int | |
1144 | packet_have_data_to_write() | |
1145 | { | |
5260325f | 1146 | return buffer_len(&output) != 0; |
8efc0c15 | 1147 | } |
1148 | ||
1149 | /* Returns true if there is not too much data to write to the connection. */ | |
1150 | ||
1151 | int | |
1152 | packet_not_very_much_data_to_write() | |
1153 | { | |
5260325f | 1154 | if (interactive_mode) |
1155 | return buffer_len(&output) < 16384; | |
1156 | else | |
1157 | return buffer_len(&output) < 128 * 1024; | |
8efc0c15 | 1158 | } |
1159 | ||
1160 | /* Informs that the current session is interactive. Sets IP flags for that. */ | |
1161 | ||
1162 | void | |
b5c334cc | 1163 | packet_set_interactive(int interactive) |
8efc0c15 | 1164 | { |
b5c334cc | 1165 | static int called = 0; |
64e0e67e | 1166 | #if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN) |
b5c334cc | 1167 | int lowdelay = IPTOS_LOWDELAY; |
1168 | int throughput = IPTOS_THROUGHPUT; | |
64e0e67e | 1169 | #endif |
5260325f | 1170 | int on = 1; |
1171 | ||
b5c334cc | 1172 | if (called) |
1173 | return; | |
1174 | called = 1; | |
1175 | ||
5260325f | 1176 | /* Record that we are in interactive mode. */ |
1177 | interactive_mode = interactive; | |
1178 | ||
48e671d5 | 1179 | /* Only set socket options if using a socket. */ |
1180 | if (!packet_connection_is_on_socket()) | |
5260325f | 1181 | return; |
48e671d5 | 1182 | /* |
f546c780 | 1183 | * IPTOS_LOWDELAY and IPTOS_THROUGHPUT are IPv4 only |
48e671d5 | 1184 | */ |
5260325f | 1185 | if (interactive) { |
aa3378df | 1186 | /* |
1187 | * Set IP options for an interactive connection. Use | |
1188 | * IPTOS_LOWDELAY and TCP_NODELAY. | |
1189 | */ | |
132dd316 | 1190 | #if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN) |
f546c780 | 1191 | if (packet_connection_is_ipv4()) { |
0e3c1f95 | 1192 | if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, |
f546c780 | 1193 | (void *) &lowdelay, sizeof(lowdelay)) < 0) |
0e3c1f95 | 1194 | error("setsockopt IPTOS_LOWDELAY: %.100s", |
f546c780 | 1195 | strerror(errno)); |
1196 | } | |
c04f75f1 | 1197 | #endif |
5260325f | 1198 | if (setsockopt(connection_in, IPPROTO_TCP, TCP_NODELAY, (void *) &on, |
48e671d5 | 1199 | sizeof(on)) < 0) |
5260325f | 1200 | error("setsockopt TCP_NODELAY: %.100s", strerror(errno)); |
f546c780 | 1201 | } else if (packet_connection_is_ipv4()) { |
aa3378df | 1202 | /* |
1203 | * Set IP options for a non-interactive connection. Use | |
1204 | * IPTOS_THROUGHPUT. | |
1205 | */ | |
132dd316 | 1206 | #if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN) |
5260325f | 1207 | if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, (void *) &throughput, |
48e671d5 | 1208 | sizeof(throughput)) < 0) |
5260325f | 1209 | error("setsockopt IPTOS_THROUGHPUT: %.100s", strerror(errno)); |
c04f75f1 | 1210 | #endif |
5260325f | 1211 | } |
8efc0c15 | 1212 | } |
1213 | ||
1214 | /* Returns true if the current connection is interactive. */ | |
1215 | ||
1216 | int | |
1217 | packet_is_interactive() | |
1218 | { | |
5260325f | 1219 | return interactive_mode; |
8efc0c15 | 1220 | } |
9d6b7add | 1221 | |
1222 | int | |
1223 | packet_set_maxsize(int s) | |
1224 | { | |
5260325f | 1225 | static int called = 0; |
1226 | if (called) { | |
7e7327a1 | 1227 | log("packet_set_maxsize: called twice: old %d new %d", |
1228 | max_packet_size, s); | |
5260325f | 1229 | return -1; |
1230 | } | |
1231 | if (s < 4 * 1024 || s > 1024 * 1024) { | |
1232 | log("packet_set_maxsize: bad size %d", s); | |
1233 | return -1; | |
1234 | } | |
1235 | log("packet_set_maxsize: setting to %d", s); | |
1236 | max_packet_size = s; | |
1237 | return s; | |
9d6b7add | 1238 | } |
a6215e53 | 1239 | |
1240 | /* | |
1241 | * 9.2. Ignored Data Message | |
cd332296 | 1242 | * |
a6215e53 | 1243 | * byte SSH_MSG_IGNORE |
1244 | * string data | |
cd332296 | 1245 | * |
a6215e53 | 1246 | * All implementations MUST understand (and ignore) this message at any |
1247 | * time (after receiving the protocol version). No implementation is | |
1248 | * required to send them. This message can be used as an additional | |
1249 | * protection measure against advanced traffic analysis techniques. | |
1250 | */ | |
1251 | /* size of current + ignore message should be n*sumlen bytes (w/o mac) */ | |
1252 | void | |
1253 | packet_inject_ignore(int sumlen) | |
1254 | { | |
95ce5599 | 1255 | int blocksize, padlen, have, need, nb, mini, nbytes; |
a6215e53 | 1256 | Enc *enc = NULL; |
1257 | ||
08dcb5d7 | 1258 | if (compat20 == 0) |
a6215e53 | 1259 | return; |
1260 | ||
1261 | have = buffer_len(&outgoing_packet); | |
1262 | debug2("packet_inject_ignore: current %d", have); | |
d1ac6175 | 1263 | if (newkeys[MODE_OUT] != NULL) |
1264 | enc = &newkeys[MODE_OUT]->enc; | |
a6215e53 | 1265 | blocksize = enc ? enc->cipher->block_size : 8; |
1266 | padlen = blocksize - (have % blocksize); | |
1267 | if (padlen < 4) | |
1268 | padlen += blocksize; | |
1269 | have += padlen; | |
1270 | have /= blocksize; /* # of blocks for current message */ | |
1271 | ||
1272 | nb = roundup(sumlen, blocksize) / blocksize; /* blocks for both */ | |
1273 | mini = roundup(5+1+4+4, blocksize) / blocksize; /* minsize ignore msg */ | |
1274 | need = nb - (have % nb); /* blocks for ignore */ | |
1275 | if (need <= mini) | |
1276 | need += nb; | |
1277 | nbytes = (need - mini) * blocksize; /* size of ignore payload */ | |
1278 | debug2("packet_inject_ignore: block %d have %d nb %d mini %d need %d", | |
1279 | blocksize, have, nb, mini, need); | |
1280 | ||
1281 | /* enqueue current message and append a ignore message */ | |
1282 | packet_send(); | |
95ce5599 | 1283 | packet_send_ignore(nbytes); |
1284 | } | |
1285 | ||
1286 | void | |
1287 | packet_send_ignore(int nbytes) | |
1288 | { | |
1289 | u_int32_t rand = 0; | |
1290 | int i; | |
1291 | ||
1292 | packet_start(compat20 ? SSH2_MSG_IGNORE : SSH_MSG_IGNORE); | |
a6215e53 | 1293 | packet_put_int(nbytes); |
1294 | for(i = 0; i < nbytes; i++) { | |
1295 | if (i % 4 == 0) | |
1296 | rand = arc4random(); | |
1297 | packet_put_char(rand & 0xff); | |
1298 | rand >>= 8; | |
1299 | } | |
1300 | } |