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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. |
a96070d4 | 16 | * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. |
bcbf86ec | 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" | |
db518d9b | 40 | RCSID("$OpenBSD: packet.c,v 1.90 2002/02/27 21:23:13 stevesk 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" | |
2ac91be1 | 62 | #include "misc.h" |
7e7327a1 | 63 | |
64 | #ifdef PACKET_DEBUG | |
65 | #define DBG(x) x | |
66 | #else | |
67 | #define DBG(x) | |
68 | #endif | |
69 | ||
aa3378df | 70 | /* |
71 | * This variable contains the file descriptors used for communicating with | |
72 | * the other side. connection_in is used for reading; connection_out for | |
73 | * writing. These can be the same descriptor, in which case it is assumed to | |
74 | * be a socket. | |
75 | */ | |
8efc0c15 | 76 | static int connection_in = -1; |
77 | static int connection_out = -1; | |
78 | ||
8efc0c15 | 79 | /* Protocol flags for the remote side. */ |
1e3b8b07 | 80 | static u_int remote_protocol_flags = 0; |
8efc0c15 | 81 | |
82 | /* Encryption context for receiving data. This is only used for decryption. */ | |
83 | static CipherContext receive_context; | |
5260325f | 84 | |
85 | /* Encryption context for sending data. This is only used for encryption. */ | |
8efc0c15 | 86 | static CipherContext send_context; |
87 | ||
88 | /* Buffer for raw input data from the socket. */ | |
89 | static Buffer input; | |
90 | ||
91 | /* Buffer for raw output data going to the socket. */ | |
92 | static Buffer output; | |
93 | ||
94 | /* Buffer for the partial outgoing packet being constructed. */ | |
95 | static Buffer outgoing_packet; | |
96 | ||
97 | /* Buffer for the incoming packet currently being processed. */ | |
98 | static Buffer incoming_packet; | |
99 | ||
100 | /* Scratch buffer for packet compression/decompression. */ | |
101 | static Buffer compression_buffer; | |
6ba22c93 | 102 | static int compression_buffer_ready = 0; |
8efc0c15 | 103 | |
104 | /* Flag indicating whether packet compression/decompression is enabled. */ | |
105 | static int packet_compression = 0; | |
106 | ||
9d6b7add | 107 | /* default maximum packet size */ |
108 | int max_packet_size = 32768; | |
109 | ||
8efc0c15 | 110 | /* Flag indicating whether this module has been initialized. */ |
111 | static int initialized = 0; | |
112 | ||
113 | /* Set to true if the connection is interactive. */ | |
114 | static int interactive_mode = 0; | |
115 | ||
7e7327a1 | 116 | /* Session key information for Encryption and MAC */ |
d1ac6175 | 117 | Newkeys *newkeys[MODE_MAX]; |
7e7327a1 | 118 | |
b4b701be | 119 | /* roundup current message to extra_pad bytes */ |
120 | static u_char extra_pad = 0; | |
121 | ||
aa3378df | 122 | /* |
123 | * Sets the descriptors used for communication. Disables encryption until | |
124 | * packet_set_encryption_key is called. | |
125 | */ | |
8efc0c15 | 126 | void |
127 | packet_set_connection(int fd_in, int fd_out) | |
128 | { | |
94ec8c6b | 129 | Cipher *none = cipher_by_name("none"); |
130 | if (none == NULL) | |
131 | fatal("packet_set_connection: cannot load cipher 'none'"); | |
5260325f | 132 | connection_in = fd_in; |
133 | connection_out = fd_out; | |
3ee832e5 | 134 | cipher_init(&send_context, none, "", 0, NULL, 0, CIPHER_ENCRYPT); |
135 | cipher_init(&receive_context, none, "", 0, NULL, 0, CIPHER_DECRYPT); | |
08dcb5d7 | 136 | newkeys[MODE_IN] = newkeys[MODE_OUT] = NULL; |
5260325f | 137 | if (!initialized) { |
138 | initialized = 1; | |
139 | buffer_init(&input); | |
140 | buffer_init(&output); | |
141 | buffer_init(&outgoing_packet); | |
142 | buffer_init(&incoming_packet); | |
143 | } | |
144 | /* Kludge: arrange the close function to be called from fatal(). */ | |
145 | fatal_add_cleanup((void (*) (void *)) packet_close, NULL); | |
8efc0c15 | 146 | } |
147 | ||
48e671d5 | 148 | /* Returns 1 if remote host is connected via socket, 0 if not. */ |
149 | ||
150 | int | |
d5bb9418 | 151 | packet_connection_is_on_socket(void) |
48e671d5 | 152 | { |
153 | struct sockaddr_storage from, to; | |
154 | socklen_t fromlen, tolen; | |
155 | ||
156 | /* filedescriptors in and out are the same, so it's a socket */ | |
157 | if (connection_in == connection_out) | |
158 | return 1; | |
159 | fromlen = sizeof(from); | |
160 | memset(&from, 0, sizeof(from)); | |
9bc5ddfe | 161 | if (getpeername(connection_in, (struct sockaddr *)&from, &fromlen) < 0) |
48e671d5 | 162 | return 0; |
163 | tolen = sizeof(to); | |
164 | memset(&to, 0, sizeof(to)); | |
9bc5ddfe | 165 | if (getpeername(connection_out, (struct sockaddr *)&to, &tolen) < 0) |
48e671d5 | 166 | return 0; |
167 | if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0) | |
168 | return 0; | |
169 | if (from.ss_family != AF_INET && from.ss_family != AF_INET6) | |
170 | return 0; | |
171 | return 1; | |
172 | } | |
173 | ||
174 | /* returns 1 if connection is via ipv4 */ | |
175 | ||
176 | int | |
d5bb9418 | 177 | packet_connection_is_ipv4(void) |
48e671d5 | 178 | { |
179 | struct sockaddr_storage to; | |
d45317d8 | 180 | socklen_t tolen = sizeof(to); |
48e671d5 | 181 | |
182 | memset(&to, 0, sizeof(to)); | |
183 | if (getsockname(connection_out, (struct sockaddr *)&to, &tolen) < 0) | |
184 | return 0; | |
185 | if (to.ss_family != AF_INET) | |
186 | return 0; | |
187 | return 1; | |
188 | } | |
189 | ||
8efc0c15 | 190 | /* Sets the connection into non-blocking mode. */ |
191 | ||
192 | void | |
d5bb9418 | 193 | packet_set_nonblocking(void) |
8efc0c15 | 194 | { |
5260325f | 195 | /* Set the socket into non-blocking mode. */ |
196 | if (fcntl(connection_in, F_SETFL, O_NONBLOCK) < 0) | |
197 | error("fcntl O_NONBLOCK: %.100s", strerror(errno)); | |
8efc0c15 | 198 | |
5260325f | 199 | if (connection_out != connection_in) { |
200 | if (fcntl(connection_out, F_SETFL, O_NONBLOCK) < 0) | |
201 | error("fcntl O_NONBLOCK: %.100s", strerror(errno)); | |
202 | } | |
8efc0c15 | 203 | } |
204 | ||
205 | /* Returns the socket used for reading. */ | |
206 | ||
207 | int | |
d5bb9418 | 208 | packet_get_connection_in(void) |
8efc0c15 | 209 | { |
5260325f | 210 | return connection_in; |
8efc0c15 | 211 | } |
212 | ||
213 | /* Returns the descriptor used for writing. */ | |
214 | ||
215 | int | |
d5bb9418 | 216 | packet_get_connection_out(void) |
8efc0c15 | 217 | { |
5260325f | 218 | return connection_out; |
8efc0c15 | 219 | } |
220 | ||
221 | /* Closes the connection and clears and frees internal data structures. */ | |
222 | ||
223 | void | |
d5bb9418 | 224 | packet_close(void) |
8efc0c15 | 225 | { |
5260325f | 226 | if (!initialized) |
227 | return; | |
228 | initialized = 0; | |
229 | if (connection_in == connection_out) { | |
230 | shutdown(connection_out, SHUT_RDWR); | |
231 | close(connection_out); | |
232 | } else { | |
233 | close(connection_in); | |
234 | close(connection_out); | |
235 | } | |
236 | buffer_free(&input); | |
237 | buffer_free(&output); | |
238 | buffer_free(&outgoing_packet); | |
239 | buffer_free(&incoming_packet); | |
6ba22c93 | 240 | if (compression_buffer_ready) { |
5260325f | 241 | buffer_free(&compression_buffer); |
242 | buffer_compress_uninit(); | |
243 | } | |
3ee832e5 | 244 | cipher_cleanup(&send_context); |
245 | cipher_cleanup(&receive_context); | |
8efc0c15 | 246 | } |
247 | ||
248 | /* Sets remote side protocol flags. */ | |
249 | ||
250 | void | |
1e3b8b07 | 251 | packet_set_protocol_flags(u_int protocol_flags) |
8efc0c15 | 252 | { |
5260325f | 253 | remote_protocol_flags = protocol_flags; |
8efc0c15 | 254 | } |
255 | ||
256 | /* Returns the remote protocol flags set earlier by the above function. */ | |
257 | ||
1e3b8b07 | 258 | u_int |
d5bb9418 | 259 | packet_get_protocol_flags(void) |
8efc0c15 | 260 | { |
5260325f | 261 | return remote_protocol_flags; |
8efc0c15 | 262 | } |
263 | ||
aa3378df | 264 | /* |
265 | * Starts packet compression from the next packet on in both directions. | |
266 | * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip. | |
267 | */ | |
8efc0c15 | 268 | |
396c147e | 269 | static void |
270 | packet_init_compression(void) | |
6ba22c93 | 271 | { |
272 | if (compression_buffer_ready == 1) | |
273 | return; | |
274 | compression_buffer_ready = 1; | |
275 | buffer_init(&compression_buffer); | |
276 | } | |
277 | ||
8efc0c15 | 278 | void |
279 | packet_start_compression(int level) | |
280 | { | |
08dcb5d7 | 281 | if (packet_compression && !compat20) |
5260325f | 282 | fatal("Compression already enabled."); |
283 | packet_compression = 1; | |
6ba22c93 | 284 | packet_init_compression(); |
285 | buffer_compress_init_send(level); | |
286 | buffer_compress_init_recv(); | |
8efc0c15 | 287 | } |
288 | ||
aa3378df | 289 | /* |
290 | * Causes any further packets to be encrypted using the given key. The same | |
291 | * key is used for both sending and reception. However, both directions are | |
292 | * encrypted independently of each other. | |
293 | */ | |
8efc0c15 | 294 | void |
1e3b8b07 | 295 | packet_set_encryption_key(const u_char *key, u_int keylen, |
94ec8c6b | 296 | int number) |
8efc0c15 | 297 | { |
94ec8c6b | 298 | Cipher *cipher = cipher_by_number(number); |
299 | if (cipher == NULL) | |
300 | fatal("packet_set_encryption_key: unknown cipher number %d", number); | |
7e7327a1 | 301 | if (keylen < 20) |
94ec8c6b | 302 | fatal("packet_set_encryption_key: keylen too small: %d", keylen); |
3ee832e5 | 303 | cipher_init(&send_context, cipher, key, keylen, NULL, 0, CIPHER_ENCRYPT); |
304 | cipher_init(&receive_context, cipher, key, keylen, NULL, 0, CIPHER_DECRYPT); | |
8efc0c15 | 305 | } |
306 | ||
08dcb5d7 | 307 | /* Start constructing a packet to send. */ |
8efc0c15 | 308 | void |
08dcb5d7 | 309 | packet_start(u_char type) |
8efc0c15 | 310 | { |
08dcb5d7 | 311 | u_char buf[9]; |
312 | int len; | |
7e7327a1 | 313 | |
12bf85ed | 314 | DBG(debug("packet_start[%d]", type)); |
08dcb5d7 | 315 | len = compat20 ? 6 : 9; |
316 | memset(buf, 0, len - 1); | |
317 | buf[len - 1] = type; | |
318 | buffer_clear(&outgoing_packet); | |
319 | buffer_append(&outgoing_packet, buf, len); | |
7e7327a1 | 320 | } |
321 | ||
08dcb5d7 | 322 | /* Append payload. */ |
8efc0c15 | 323 | void |
324 | packet_put_char(int value) | |
325 | { | |
5260325f | 326 | char ch = value; |
327 | buffer_append(&outgoing_packet, &ch, 1); | |
8efc0c15 | 328 | } |
8efc0c15 | 329 | void |
1e3b8b07 | 330 | packet_put_int(u_int value) |
8efc0c15 | 331 | { |
5260325f | 332 | buffer_put_int(&outgoing_packet, value); |
8efc0c15 | 333 | } |
8efc0c15 | 334 | void |
6c0fa2b1 | 335 | packet_put_string(const void *buf, u_int len) |
8efc0c15 | 336 | { |
5260325f | 337 | buffer_put_string(&outgoing_packet, buf, len); |
8efc0c15 | 338 | } |
7e7327a1 | 339 | void |
340 | packet_put_cstring(const char *str) | |
341 | { | |
449c5ba5 | 342 | buffer_put_cstring(&outgoing_packet, str); |
7e7327a1 | 343 | } |
7e7327a1 | 344 | void |
6c0fa2b1 | 345 | packet_put_raw(const void *buf, u_int len) |
7e7327a1 | 346 | { |
347 | buffer_append(&outgoing_packet, buf, len); | |
348 | } | |
8efc0c15 | 349 | void |
5260325f | 350 | packet_put_bignum(BIGNUM * value) |
8efc0c15 | 351 | { |
5260325f | 352 | buffer_put_bignum(&outgoing_packet, value); |
8efc0c15 | 353 | } |
7e7327a1 | 354 | void |
355 | packet_put_bignum2(BIGNUM * value) | |
356 | { | |
357 | buffer_put_bignum2(&outgoing_packet, value); | |
358 | } | |
8efc0c15 | 359 | |
aa3378df | 360 | /* |
361 | * Finalizes and sends the packet. If the encryption key has been set, | |
362 | * encrypts the packet before sending. | |
363 | */ | |
5260325f | 364 | |
396c147e | 365 | static void |
5ca51e19 | 366 | packet_send1(void) |
8efc0c15 | 367 | { |
a318bbf4 | 368 | u_char buf[8], *cp; |
5260325f | 369 | int i, padding, len; |
1e3b8b07 | 370 | u_int checksum; |
5260325f | 371 | u_int32_t rand = 0; |
372 | ||
aa3378df | 373 | /* |
374 | * If using packet compression, compress the payload of the outgoing | |
375 | * packet. | |
376 | */ | |
5260325f | 377 | if (packet_compression) { |
378 | buffer_clear(&compression_buffer); | |
379 | /* Skip padding. */ | |
380 | buffer_consume(&outgoing_packet, 8); | |
381 | /* padding */ | |
382 | buffer_append(&compression_buffer, "\0\0\0\0\0\0\0\0", 8); | |
383 | buffer_compress(&outgoing_packet, &compression_buffer); | |
384 | buffer_clear(&outgoing_packet); | |
385 | buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer), | |
184eed6a | 386 | buffer_len(&compression_buffer)); |
5260325f | 387 | } |
388 | /* Compute packet length without padding (add checksum, remove padding). */ | |
389 | len = buffer_len(&outgoing_packet) + 4 - 8; | |
390 | ||
1d1ffb87 | 391 | /* Insert padding. Initialized to zero in packet_start1() */ |
5260325f | 392 | padding = 8 - len % 8; |
3ee832e5 | 393 | if (!send_context.plaintext) { |
5260325f | 394 | cp = buffer_ptr(&outgoing_packet); |
395 | for (i = 0; i < padding; i++) { | |
396 | if (i % 4 == 0) | |
397 | rand = arc4random(); | |
398 | cp[7 - i] = rand & 0xff; | |
399 | rand >>= 8; | |
400 | } | |
401 | } | |
402 | buffer_consume(&outgoing_packet, 8 - padding); | |
403 | ||
404 | /* Add check bytes. */ | |
20905a8e | 405 | checksum = ssh_crc32(buffer_ptr(&outgoing_packet), |
2e73a022 | 406 | buffer_len(&outgoing_packet)); |
5260325f | 407 | PUT_32BIT(buf, checksum); |
408 | buffer_append(&outgoing_packet, buf, 4); | |
8efc0c15 | 409 | |
410 | #ifdef PACKET_DEBUG | |
5260325f | 411 | fprintf(stderr, "packet_send plain: "); |
412 | buffer_dump(&outgoing_packet); | |
8efc0c15 | 413 | #endif |
414 | ||
5260325f | 415 | /* Append to output. */ |
416 | PUT_32BIT(buf, len); | |
417 | buffer_append(&output, buf, 4); | |
6c0fa2b1 | 418 | cp = buffer_append_space(&output, buffer_len(&outgoing_packet)); |
3ee832e5 | 419 | cipher_crypt(&send_context, cp, buffer_ptr(&outgoing_packet), |
184eed6a | 420 | buffer_len(&outgoing_packet)); |
5260325f | 421 | |
8efc0c15 | 422 | #ifdef PACKET_DEBUG |
5260325f | 423 | fprintf(stderr, "encrypted: "); |
424 | buffer_dump(&output); | |
8efc0c15 | 425 | #endif |
426 | ||
5260325f | 427 | buffer_clear(&outgoing_packet); |
8efc0c15 | 428 | |
aa3378df | 429 | /* |
430 | * Note that the packet is now only buffered in output. It won\'t be | |
431 | * actually sent until packet_write_wait or packet_write_poll is | |
432 | * called. | |
433 | */ | |
8efc0c15 | 434 | } |
435 | ||
63284fbb | 436 | static void |
d1ac6175 | 437 | set_newkeys(int mode) |
438 | { | |
439 | Enc *enc; | |
440 | Mac *mac; | |
441 | Comp *comp; | |
442 | CipherContext *cc; | |
3ee832e5 | 443 | int encrypt; |
d1ac6175 | 444 | |
445 | debug("newkeys: mode %d", mode); | |
446 | ||
3ee832e5 | 447 | if (mode == MODE_OUT) { |
448 | cc = &send_context; | |
449 | encrypt = CIPHER_ENCRYPT; | |
450 | } else { | |
451 | cc = &receive_context; | |
452 | encrypt = CIPHER_DECRYPT; | |
453 | } | |
d1ac6175 | 454 | if (newkeys[mode] != NULL) { |
455 | debug("newkeys: rekeying"); | |
3ee832e5 | 456 | cipher_cleanup(cc); |
a7ca6275 | 457 | enc = &newkeys[mode]->enc; |
458 | mac = &newkeys[mode]->mac; | |
459 | comp = &newkeys[mode]->comp; | |
cd332296 | 460 | memset(mac->key, 0, mac->key_len); |
a7ca6275 | 461 | xfree(enc->name); |
462 | xfree(enc->iv); | |
463 | xfree(enc->key); | |
464 | xfree(mac->name); | |
465 | xfree(mac->key); | |
466 | xfree(comp->name); | |
d8ee838b | 467 | xfree(newkeys[mode]); |
d1ac6175 | 468 | } |
469 | newkeys[mode] = kex_get_newkeys(mode); | |
470 | if (newkeys[mode] == NULL) | |
471 | fatal("newkeys: no keys for mode %d", mode); | |
472 | enc = &newkeys[mode]->enc; | |
473 | mac = &newkeys[mode]->mac; | |
474 | comp = &newkeys[mode]->comp; | |
475 | if (mac->md != NULL) | |
476 | mac->enabled = 1; | |
477 | DBG(debug("cipher_init_context: %d", mode)); | |
3ee832e5 | 478 | cipher_init(cc, enc->cipher, enc->key, enc->key_len, |
479 | enc->iv, enc->block_size, encrypt); | |
63284fbb | 480 | memset(enc->iv, 0, enc->block_size); |
481 | memset(enc->key, 0, enc->key_len); | |
d1ac6175 | 482 | if (comp->type != 0 && comp->enabled == 0) { |
6ba22c93 | 483 | packet_init_compression(); |
484 | if (mode == MODE_OUT) | |
485 | buffer_compress_init_send(6); | |
486 | else | |
487 | buffer_compress_init_recv(); | |
d1ac6175 | 488 | comp->enabled = 1; |
d1ac6175 | 489 | } |
490 | } | |
491 | ||
7e7327a1 | 492 | /* |
493 | * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue) | |
494 | */ | |
396c147e | 495 | static void |
5ca51e19 | 496 | packet_send2(void) |
7e7327a1 | 497 | { |
63284fbb | 498 | static u_int32_t seqnr = 0; |
a318bbf4 | 499 | u_char type, *cp, *macbuf = NULL; |
b4b701be | 500 | u_char padlen, pad; |
1e3b8b07 | 501 | u_int packet_length = 0; |
b4b701be | 502 | u_int i, len; |
7e7327a1 | 503 | u_int32_t rand = 0; |
7e7327a1 | 504 | Enc *enc = NULL; |
505 | Mac *mac = NULL; | |
506 | Comp *comp = NULL; | |
507 | int block_size; | |
508 | ||
d1ac6175 | 509 | if (newkeys[MODE_OUT] != NULL) { |
510 | enc = &newkeys[MODE_OUT]->enc; | |
511 | mac = &newkeys[MODE_OUT]->mac; | |
512 | comp = &newkeys[MODE_OUT]->comp; | |
7e7327a1 | 513 | } |
3ee832e5 | 514 | block_size = enc ? enc->block_size : 8; |
7e7327a1 | 515 | |
a318bbf4 | 516 | cp = buffer_ptr(&outgoing_packet); |
517 | type = cp[5]; | |
7e7327a1 | 518 | |
519 | #ifdef PACKET_DEBUG | |
520 | fprintf(stderr, "plain: "); | |
521 | buffer_dump(&outgoing_packet); | |
522 | #endif | |
523 | ||
524 | if (comp && comp->enabled) { | |
525 | len = buffer_len(&outgoing_packet); | |
526 | /* skip header, compress only payload */ | |
527 | buffer_consume(&outgoing_packet, 5); | |
528 | buffer_clear(&compression_buffer); | |
529 | buffer_compress(&outgoing_packet, &compression_buffer); | |
530 | buffer_clear(&outgoing_packet); | |
531 | buffer_append(&outgoing_packet, "\0\0\0\0\0", 5); | |
532 | buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer), | |
533 | buffer_len(&compression_buffer)); | |
534 | DBG(debug("compression: raw %d compressed %d", len, | |
535 | buffer_len(&outgoing_packet))); | |
536 | } | |
537 | ||
538 | /* sizeof (packet_len + pad_len + payload) */ | |
539 | len = buffer_len(&outgoing_packet); | |
540 | ||
541 | /* | |
542 | * calc size of padding, alloc space, get random data, | |
543 | * minimum padding is 4 bytes | |
544 | */ | |
545 | padlen = block_size - (len % block_size); | |
546 | if (padlen < 4) | |
547 | padlen += block_size; | |
b4b701be | 548 | if (extra_pad) { |
549 | /* will wrap if extra_pad+padlen > 255 */ | |
550 | extra_pad = roundup(extra_pad, block_size); | |
551 | pad = extra_pad - ((len + padlen) % extra_pad); | |
552 | debug("packet_send2: adding %d (len %d padlen %d extra_pad %d)", | |
553 | pad, len, padlen, extra_pad); | |
554 | padlen += pad; | |
555 | extra_pad = 0; | |
556 | } | |
6c0fa2b1 | 557 | cp = buffer_append_space(&outgoing_packet, padlen); |
3ee832e5 | 558 | if (enc && !send_context.plaintext) { |
1d1ffb87 | 559 | /* random padding */ |
7e7327a1 | 560 | for (i = 0; i < padlen; i++) { |
561 | if (i % 4 == 0) | |
562 | rand = arc4random(); | |
563 | cp[i] = rand & 0xff; | |
6e18cb71 | 564 | rand >>= 8; |
7e7327a1 | 565 | } |
1d1ffb87 | 566 | } else { |
567 | /* clear padding */ | |
568 | memset(cp, 0, padlen); | |
7e7327a1 | 569 | } |
570 | /* packet_length includes payload, padding and padding length field */ | |
571 | packet_length = buffer_len(&outgoing_packet) - 4; | |
a318bbf4 | 572 | cp = buffer_ptr(&outgoing_packet); |
573 | PUT_32BIT(cp, packet_length); | |
574 | cp[4] = padlen; | |
7e7327a1 | 575 | DBG(debug("send: len %d (includes padlen %d)", packet_length+4, padlen)); |
576 | ||
577 | /* compute MAC over seqnr and packet(length fields, payload, padding) */ | |
578 | if (mac && mac->enabled) { | |
63284fbb | 579 | macbuf = mac_compute(mac, seqnr, |
20905a8e | 580 | buffer_ptr(&outgoing_packet), |
b2552997 | 581 | buffer_len(&outgoing_packet)); |
63284fbb | 582 | DBG(debug("done calc MAC out #%d", seqnr)); |
7e7327a1 | 583 | } |
584 | /* encrypt packet and append to output buffer. */ | |
6c0fa2b1 | 585 | cp = buffer_append_space(&output, buffer_len(&outgoing_packet)); |
3ee832e5 | 586 | cipher_crypt(&send_context, cp, buffer_ptr(&outgoing_packet), |
7e7327a1 | 587 | buffer_len(&outgoing_packet)); |
588 | /* append unencrypted MAC */ | |
589 | if (mac && mac->enabled) | |
590 | buffer_append(&output, (char *)macbuf, mac->mac_len); | |
591 | #ifdef PACKET_DEBUG | |
592 | fprintf(stderr, "encrypted: "); | |
593 | buffer_dump(&output); | |
594 | #endif | |
6ae2364d | 595 | /* increment sequence number for outgoing packets */ |
63284fbb | 596 | if (++seqnr == 0) |
6ae2364d | 597 | log("outgoing seqnr wraps around"); |
7e7327a1 | 598 | buffer_clear(&outgoing_packet); |
599 | ||
d1ac6175 | 600 | if (type == SSH2_MSG_NEWKEYS) |
601 | set_newkeys(MODE_OUT); | |
7e7327a1 | 602 | } |
603 | ||
604 | void | |
d5bb9418 | 605 | packet_send(void) |
7e7327a1 | 606 | { |
08dcb5d7 | 607 | if (compat20) |
7e7327a1 | 608 | packet_send2(); |
609 | else | |
610 | packet_send1(); | |
611 | DBG(debug("packet_send done")); | |
612 | } | |
613 | ||
aa3378df | 614 | /* |
615 | * Waits until a packet has been received, and returns its type. Note that | |
616 | * no other data is processed until this returns, so this function should not | |
617 | * be used during the interactive session. | |
618 | */ | |
8efc0c15 | 619 | |
620 | int | |
54a5250f | 621 | packet_read_seqnr(u_int32_t *seqnr_p) |
8efc0c15 | 622 | { |
5260325f | 623 | int type, len; |
20e04e90 | 624 | fd_set *setp; |
5260325f | 625 | char buf[8192]; |
7e7327a1 | 626 | DBG(debug("packet_read()")); |
5260325f | 627 | |
20e04e90 | 628 | setp = (fd_set *)xmalloc(howmany(connection_in+1, NFDBITS) * |
629 | sizeof(fd_mask)); | |
630 | ||
5260325f | 631 | /* Since we are blocking, ensure that all written packets have been sent. */ |
632 | packet_write_wait(); | |
633 | ||
634 | /* Stay in the loop until we have received a complete packet. */ | |
635 | for (;;) { | |
636 | /* Try to read a packet from the buffer. */ | |
54a5250f | 637 | type = packet_read_poll_seqnr(seqnr_p); |
08dcb5d7 | 638 | if (!compat20 && ( |
1d1ffb87 | 639 | type == SSH_SMSG_SUCCESS |
5260325f | 640 | || type == SSH_SMSG_FAILURE |
641 | || type == SSH_CMSG_EOF | |
1d1ffb87 | 642 | || type == SSH_CMSG_EXIT_CONFIRMATION)) |
95500969 | 643 | packet_check_eom(); |
5260325f | 644 | /* If we got a packet, return it. */ |
20e04e90 | 645 | if (type != SSH_MSG_NONE) { |
646 | xfree(setp); | |
5260325f | 647 | return type; |
20e04e90 | 648 | } |
aa3378df | 649 | /* |
650 | * Otherwise, wait for some data to arrive, add it to the | |
651 | * buffer, and try again. | |
652 | */ | |
20e04e90 | 653 | memset(setp, 0, howmany(connection_in + 1, NFDBITS) * |
654 | sizeof(fd_mask)); | |
655 | FD_SET(connection_in, setp); | |
aa3378df | 656 | |
5260325f | 657 | /* Wait for some data to arrive. */ |
20e04e90 | 658 | while (select(connection_in + 1, setp, NULL, NULL, NULL) == -1 && |
fd193ca4 | 659 | (errno == EAGAIN || errno == EINTR)) |
660 | ; | |
aa3378df | 661 | |
5260325f | 662 | /* Read data from the socket. */ |
663 | len = read(connection_in, buf, sizeof(buf)); | |
89cafde6 | 664 | if (len == 0) { |
665 | log("Connection closed by %.200s", get_remote_ipaddr()); | |
666 | fatal_cleanup(); | |
667 | } | |
5260325f | 668 | if (len < 0) |
669 | fatal("Read from socket failed: %.100s", strerror(errno)); | |
670 | /* Append it to the buffer. */ | |
671 | packet_process_incoming(buf, len); | |
672 | } | |
673 | /* NOTREACHED */ | |
8efc0c15 | 674 | } |
675 | ||
24ca6821 | 676 | int |
54a5250f | 677 | packet_read(void) |
24ca6821 | 678 | { |
54a5250f | 679 | return packet_read_seqnr(NULL); |
24ca6821 | 680 | } |
681 | ||
aa3378df | 682 | /* |
683 | * Waits until a packet has been received, verifies that its type matches | |
684 | * that given, and gives a fatal error and exits if there is a mismatch. | |
685 | */ | |
8efc0c15 | 686 | |
687 | void | |
54a5250f | 688 | packet_read_expect(int expected_type) |
8efc0c15 | 689 | { |
5260325f | 690 | int type; |
8efc0c15 | 691 | |
54a5250f | 692 | type = packet_read(); |
5260325f | 693 | if (type != expected_type) |
694 | packet_disconnect("Protocol error: expected packet type %d, got %d", | |
7e7327a1 | 695 | expected_type, type); |
8efc0c15 | 696 | } |
697 | ||
698 | /* Checks if a full packet is available in the data received so far via | |
5260325f | 699 | * packet_process_incoming. If so, reads the packet; otherwise returns |
700 | * SSH_MSG_NONE. This does not wait for data from the connection. | |
701 | * | |
702 | * SSH_MSG_DISCONNECT is handled specially here. Also, | |
703 | * SSH_MSG_IGNORE messages are skipped by this function and are never returned | |
704 | * to higher levels. | |
5260325f | 705 | */ |
8efc0c15 | 706 | |
396c147e | 707 | static int |
54a5250f | 708 | packet_read_poll1(void) |
8efc0c15 | 709 | { |
1e3b8b07 | 710 | u_int len, padded_len; |
a318bbf4 | 711 | u_char *cp, type; |
1e3b8b07 | 712 | u_int checksum, stored_checksum; |
5260325f | 713 | |
5260325f | 714 | /* Check if input size is less than minimum packet size. */ |
715 | if (buffer_len(&input) < 4 + 8) | |
716 | return SSH_MSG_NONE; | |
717 | /* Get length of incoming packet. */ | |
a318bbf4 | 718 | cp = buffer_ptr(&input); |
719 | len = GET_32BIT(cp); | |
5260325f | 720 | if (len < 1 + 2 + 2 || len > 256 * 1024) |
721 | packet_disconnect("Bad packet length %d.", len); | |
722 | padded_len = (len + 8) & ~7; | |
723 | ||
724 | /* Check if the packet has been entirely received. */ | |
725 | if (buffer_len(&input) < 4 + padded_len) | |
726 | return SSH_MSG_NONE; | |
727 | ||
728 | /* The entire packet is in buffer. */ | |
729 | ||
730 | /* Consume packet length. */ | |
731 | buffer_consume(&input, 4); | |
732 | ||
08dcb5d7 | 733 | /* |
734 | * Cryptographic attack detector for ssh | |
735 | * (C)1998 CORE-SDI, Buenos Aires Argentina | |
736 | * Ariel Futoransky(futo@core-sdi.com) | |
737 | */ | |
3ee832e5 | 738 | if (!receive_context.plaintext && |
08dcb5d7 | 739 | detect_attack(buffer_ptr(&input), padded_len, NULL) == DEATTACK_DETECTED) |
740 | packet_disconnect("crc32 compensation attack: network attack detected"); | |
741 | ||
742 | /* Decrypt data to incoming_packet. */ | |
5260325f | 743 | buffer_clear(&incoming_packet); |
6c0fa2b1 | 744 | cp = buffer_append_space(&incoming_packet, padded_len); |
3ee832e5 | 745 | cipher_crypt(&receive_context, cp, buffer_ptr(&input), padded_len); |
08dcb5d7 | 746 | |
5260325f | 747 | buffer_consume(&input, padded_len); |
8efc0c15 | 748 | |
749 | #ifdef PACKET_DEBUG | |
5260325f | 750 | fprintf(stderr, "read_poll plain: "); |
751 | buffer_dump(&incoming_packet); | |
8efc0c15 | 752 | #endif |
5260325f | 753 | |
754 | /* Compute packet checksum. */ | |
20905a8e | 755 | checksum = ssh_crc32(buffer_ptr(&incoming_packet), |
7e7327a1 | 756 | buffer_len(&incoming_packet) - 4); |
5260325f | 757 | |
758 | /* Skip padding. */ | |
759 | buffer_consume(&incoming_packet, 8 - len % 8); | |
760 | ||
761 | /* Test check bytes. */ | |
5260325f | 762 | if (len != buffer_len(&incoming_packet)) |
24ca6821 | 763 | packet_disconnect("packet_read_poll1: len %d != buffer_len %d.", |
7e7327a1 | 764 | len, buffer_len(&incoming_packet)); |
5260325f | 765 | |
a318bbf4 | 766 | cp = (u_char *)buffer_ptr(&incoming_packet) + len - 4; |
767 | stored_checksum = GET_32BIT(cp); | |
5260325f | 768 | if (checksum != stored_checksum) |
769 | packet_disconnect("Corrupted check bytes on input."); | |
770 | buffer_consume_end(&incoming_packet, 4); | |
771 | ||
5260325f | 772 | if (packet_compression) { |
773 | buffer_clear(&compression_buffer); | |
774 | buffer_uncompress(&incoming_packet, &compression_buffer); | |
775 | buffer_clear(&incoming_packet); | |
776 | buffer_append(&incoming_packet, buffer_ptr(&compression_buffer), | |
7e7327a1 | 777 | buffer_len(&compression_buffer)); |
5260325f | 778 | } |
08dcb5d7 | 779 | type = buffer_get_char(&incoming_packet); |
08dcb5d7 | 780 | return type; |
5260325f | 781 | } |
782 | ||
396c147e | 783 | static int |
54a5250f | 784 | packet_read_poll2(u_int32_t *seqnr_p) |
7e7327a1 | 785 | { |
63284fbb | 786 | static u_int32_t seqnr = 0; |
b2552997 | 787 | static u_int packet_length = 0; |
1e3b8b07 | 788 | u_int padlen, need; |
a318bbf4 | 789 | u_char *macbuf, *cp, type; |
7e7327a1 | 790 | int maclen, block_size; |
791 | Enc *enc = NULL; | |
792 | Mac *mac = NULL; | |
793 | Comp *comp = NULL; | |
794 | ||
d1ac6175 | 795 | if (newkeys[MODE_IN] != NULL) { |
796 | enc = &newkeys[MODE_IN]->enc; | |
797 | mac = &newkeys[MODE_IN]->mac; | |
798 | comp = &newkeys[MODE_IN]->comp; | |
7e7327a1 | 799 | } |
800 | maclen = mac && mac->enabled ? mac->mac_len : 0; | |
3ee832e5 | 801 | block_size = enc ? enc->block_size : 8; |
7e7327a1 | 802 | |
803 | if (packet_length == 0) { | |
804 | /* | |
805 | * check if input size is less than the cipher block size, | |
806 | * decrypt first block and extract length of incoming packet | |
807 | */ | |
808 | if (buffer_len(&input) < block_size) | |
809 | return SSH_MSG_NONE; | |
810 | buffer_clear(&incoming_packet); | |
6c0fa2b1 | 811 | cp = buffer_append_space(&incoming_packet, block_size); |
3ee832e5 | 812 | cipher_crypt(&receive_context, cp, buffer_ptr(&input), |
7e7327a1 | 813 | block_size); |
a318bbf4 | 814 | cp = buffer_ptr(&incoming_packet); |
815 | packet_length = GET_32BIT(cp); | |
7e7327a1 | 816 | if (packet_length < 1 + 4 || packet_length > 256 * 1024) { |
817 | buffer_dump(&incoming_packet); | |
818 | packet_disconnect("Bad packet length %d.", packet_length); | |
819 | } | |
820 | DBG(debug("input: packet len %d", packet_length+4)); | |
821 | buffer_consume(&input, block_size); | |
822 | } | |
823 | /* we have a partial packet of block_size bytes */ | |
824 | need = 4 + packet_length - block_size; | |
825 | DBG(debug("partial packet %d, need %d, maclen %d", block_size, | |
826 | need, maclen)); | |
827 | if (need % block_size != 0) | |
828 | fatal("padding error: need %d block %d mod %d", | |
829 | need, block_size, need % block_size); | |
830 | /* | |
831 | * check if the entire packet has been received and | |
832 | * decrypt into incoming_packet | |
833 | */ | |
834 | if (buffer_len(&input) < need + maclen) | |
835 | return SSH_MSG_NONE; | |
836 | #ifdef PACKET_DEBUG | |
837 | fprintf(stderr, "read_poll enc/full: "); | |
838 | buffer_dump(&input); | |
839 | #endif | |
6c0fa2b1 | 840 | cp = buffer_append_space(&incoming_packet, need); |
3ee832e5 | 841 | cipher_crypt(&receive_context, cp, buffer_ptr(&input), need); |
7e7327a1 | 842 | buffer_consume(&input, need); |
843 | /* | |
844 | * compute MAC over seqnr and packet, | |
845 | * increment sequence number for incoming packet | |
846 | */ | |
6ae2364d | 847 | if (mac && mac->enabled) { |
63284fbb | 848 | macbuf = mac_compute(mac, seqnr, |
20905a8e | 849 | buffer_ptr(&incoming_packet), |
b2552997 | 850 | buffer_len(&incoming_packet)); |
7e7327a1 | 851 | if (memcmp(macbuf, buffer_ptr(&input), mac->mac_len) != 0) |
94ec8c6b | 852 | packet_disconnect("Corrupted MAC on input."); |
63284fbb | 853 | DBG(debug("MAC #%d ok", seqnr)); |
7e7327a1 | 854 | buffer_consume(&input, mac->mac_len); |
855 | } | |
24ca6821 | 856 | if (seqnr_p != NULL) |
63284fbb | 857 | *seqnr_p = seqnr; |
858 | if (++seqnr == 0) | |
6ae2364d | 859 | log("incoming seqnr wraps around"); |
7e7327a1 | 860 | |
861 | /* get padlen */ | |
6c0fa2b1 | 862 | cp = buffer_ptr(&incoming_packet); |
a318bbf4 | 863 | padlen = cp[4]; |
7e7327a1 | 864 | DBG(debug("input: padlen %d", padlen)); |
865 | if (padlen < 4) | |
866 | packet_disconnect("Corrupted padlen %d on input.", padlen); | |
867 | ||
868 | /* skip packet size + padlen, discard padding */ | |
869 | buffer_consume(&incoming_packet, 4 + 1); | |
870 | buffer_consume_end(&incoming_packet, padlen); | |
871 | ||
872 | DBG(debug("input: len before de-compress %d", buffer_len(&incoming_packet))); | |
873 | if (comp && comp->enabled) { | |
874 | buffer_clear(&compression_buffer); | |
875 | buffer_uncompress(&incoming_packet, &compression_buffer); | |
876 | buffer_clear(&incoming_packet); | |
877 | buffer_append(&incoming_packet, buffer_ptr(&compression_buffer), | |
878 | buffer_len(&compression_buffer)); | |
879 | DBG(debug("input: len after de-compress %d", buffer_len(&incoming_packet))); | |
880 | } | |
881 | /* | |
882 | * get packet type, implies consume. | |
883 | * return length of payload (without type field) | |
884 | */ | |
08dcb5d7 | 885 | type = buffer_get_char(&incoming_packet); |
d1ac6175 | 886 | if (type == SSH2_MSG_NEWKEYS) |
887 | set_newkeys(MODE_IN); | |
7e7327a1 | 888 | #ifdef PACKET_DEBUG |
12bf85ed | 889 | fprintf(stderr, "read/plain[%d]:\r\n", type); |
7e7327a1 | 890 | buffer_dump(&incoming_packet); |
891 | #endif | |
08dcb5d7 | 892 | /* reset for next packet */ |
893 | packet_length = 0; | |
894 | return type; | |
7e7327a1 | 895 | } |
896 | ||
897 | int | |
54a5250f | 898 | packet_read_poll_seqnr(u_int32_t *seqnr_p) |
7e7327a1 | 899 | { |
5a5f4c37 | 900 | int reason, seqnr; |
08dcb5d7 | 901 | u_char type; |
7e7327a1 | 902 | char *msg; |
7e7327a1 | 903 | |
08dcb5d7 | 904 | for (;;) { |
905 | if (compat20) { | |
54a5250f | 906 | type = packet_read_poll2(seqnr_p); |
08dcb5d7 | 907 | if (type) |
7e7327a1 | 908 | DBG(debug("received packet type %d", type)); |
6aacefa7 | 909 | switch (type) { |
7e7327a1 | 910 | case SSH2_MSG_IGNORE: |
911 | break; | |
912 | case SSH2_MSG_DEBUG: | |
913 | packet_get_char(); | |
914 | msg = packet_get_string(NULL); | |
915 | debug("Remote: %.900s", msg); | |
916 | xfree(msg); | |
917 | msg = packet_get_string(NULL); | |
918 | xfree(msg); | |
919 | break; | |
920 | case SSH2_MSG_DISCONNECT: | |
921 | reason = packet_get_int(); | |
922 | msg = packet_get_string(NULL); | |
7c49df64 | 923 | log("Received disconnect from %s: %d: %.400s", get_remote_ipaddr(), |
924 | reason, msg); | |
7e7327a1 | 925 | xfree(msg); |
926 | fatal_cleanup(); | |
927 | break; | |
5a5f4c37 | 928 | case SSH2_MSG_UNIMPLEMENTED: |
929 | seqnr = packet_get_int(); | |
930 | debug("Received SSH2_MSG_UNIMPLEMENTED for %d", seqnr); | |
931 | break; | |
7e7327a1 | 932 | default: |
933 | return type; | |
934 | break; | |
2b87da3b | 935 | } |
7e7327a1 | 936 | } else { |
54a5250f | 937 | type = packet_read_poll1(); |
6aacefa7 | 938 | switch (type) { |
7e7327a1 | 939 | case SSH_MSG_IGNORE: |
940 | break; | |
941 | case SSH_MSG_DEBUG: | |
942 | msg = packet_get_string(NULL); | |
943 | debug("Remote: %.900s", msg); | |
944 | xfree(msg); | |
945 | break; | |
946 | case SSH_MSG_DISCONNECT: | |
947 | msg = packet_get_string(NULL); | |
7c49df64 | 948 | log("Received disconnect from %s: %.400s", get_remote_ipaddr(), |
949 | msg); | |
7e7327a1 | 950 | fatal_cleanup(); |
951 | xfree(msg); | |
952 | break; | |
953 | default: | |
08dcb5d7 | 954 | if (type) |
7e7327a1 | 955 | DBG(debug("received packet type %d", type)); |
956 | return type; | |
957 | break; | |
2b87da3b | 958 | } |
7e7327a1 | 959 | } |
960 | } | |
961 | } | |
962 | ||
24ca6821 | 963 | int |
54a5250f | 964 | packet_read_poll(void) |
24ca6821 | 965 | { |
54a5250f | 966 | return packet_read_poll_seqnr(NULL); |
24ca6821 | 967 | } |
968 | ||
aa3378df | 969 | /* |
970 | * Buffers the given amount of input characters. This is intended to be used | |
971 | * together with packet_read_poll. | |
972 | */ | |
8efc0c15 | 973 | |
974 | void | |
1e3b8b07 | 975 | packet_process_incoming(const char *buf, u_int len) |
8efc0c15 | 976 | { |
5260325f | 977 | buffer_append(&input, buf, len); |
8efc0c15 | 978 | } |
979 | ||
980 | /* Returns a character from the packet. */ | |
981 | ||
1e3b8b07 | 982 | u_int |
d5bb9418 | 983 | packet_get_char(void) |
8efc0c15 | 984 | { |
5260325f | 985 | char ch; |
986 | buffer_get(&incoming_packet, &ch, 1); | |
1e3b8b07 | 987 | return (u_char) ch; |
8efc0c15 | 988 | } |
989 | ||
990 | /* Returns an integer from the packet data. */ | |
991 | ||
1e3b8b07 | 992 | u_int |
d5bb9418 | 993 | packet_get_int(void) |
8efc0c15 | 994 | { |
5260325f | 995 | return buffer_get_int(&incoming_packet); |
8efc0c15 | 996 | } |
997 | ||
aa3378df | 998 | /* |
999 | * Returns an arbitrary precision integer from the packet data. The integer | |
1000 | * must have been initialized before this call. | |
1001 | */ | |
8efc0c15 | 1002 | |
1003 | void | |
20b279e6 | 1004 | packet_get_bignum(BIGNUM * value) |
8efc0c15 | 1005 | { |
4ef6f649 | 1006 | buffer_get_bignum(&incoming_packet, value); |
8efc0c15 | 1007 | } |
1008 | ||
7e7327a1 | 1009 | void |
20b279e6 | 1010 | packet_get_bignum2(BIGNUM * value) |
7e7327a1 | 1011 | { |
4ef6f649 | 1012 | buffer_get_bignum2(&incoming_packet, value); |
7e7327a1 | 1013 | } |
1014 | ||
6c0fa2b1 | 1015 | void * |
7e7327a1 | 1016 | packet_get_raw(int *length_ptr) |
1017 | { | |
1018 | int bytes = buffer_len(&incoming_packet); | |
1019 | if (length_ptr != NULL) | |
1020 | *length_ptr = bytes; | |
1021 | return buffer_ptr(&incoming_packet); | |
1022 | } | |
1023 | ||
6ae2364d | 1024 | int |
1025 | packet_remaining(void) | |
1026 | { | |
1027 | return buffer_len(&incoming_packet); | |
1028 | } | |
1029 | ||
aa3378df | 1030 | /* |
1031 | * Returns a string from the packet data. The string is allocated using | |
1032 | * xmalloc; it is the responsibility of the calling program to free it when | |
1033 | * no longer needed. The length_ptr argument may be NULL, or point to an | |
1034 | * integer into which the length of the string is stored. | |
1035 | */ | |
8efc0c15 | 1036 | |
6c0fa2b1 | 1037 | void * |
1e3b8b07 | 1038 | packet_get_string(u_int *length_ptr) |
8efc0c15 | 1039 | { |
5260325f | 1040 | return buffer_get_string(&incoming_packet, length_ptr); |
8efc0c15 | 1041 | } |
1042 | ||
aa3378df | 1043 | /* |
1044 | * Sends a diagnostic message from the server to the client. This message | |
1045 | * can be sent at any time (but not while constructing another message). The | |
1046 | * message is printed immediately, but only if the client is being executed | |
1047 | * in verbose mode. These messages are primarily intended to ease debugging | |
1048 | * authentication problems. The length of the formatted message must not | |
1049 | * exceed 1024 bytes. This will automatically call packet_write_wait. | |
1050 | */ | |
8efc0c15 | 1051 | |
1052 | void | |
5260325f | 1053 | packet_send_debug(const char *fmt,...) |
8efc0c15 | 1054 | { |
5260325f | 1055 | char buf[1024]; |
1056 | va_list args; | |
1057 | ||
f72fc97f | 1058 | if (compat20 && (datafellows & SSH_BUG_DEBUG)) |
1059 | return; | |
1060 | ||
5260325f | 1061 | va_start(args, fmt); |
1062 | vsnprintf(buf, sizeof(buf), fmt, args); | |
1063 | va_end(args); | |
1064 | ||
c4bc58eb | 1065 | if (compat20) { |
1066 | packet_start(SSH2_MSG_DEBUG); | |
1067 | packet_put_char(0); /* bool: always display */ | |
1068 | packet_put_cstring(buf); | |
1069 | packet_put_cstring(""); | |
1070 | } else { | |
1071 | packet_start(SSH_MSG_DEBUG); | |
1072 | packet_put_cstring(buf); | |
1073 | } | |
5260325f | 1074 | packet_send(); |
1075 | packet_write_wait(); | |
8efc0c15 | 1076 | } |
1077 | ||
aa3378df | 1078 | /* |
1079 | * Logs the error plus constructs and sends a disconnect packet, closes the | |
1080 | * connection, and exits. This function never returns. The error message | |
1081 | * should not contain a newline. The length of the formatted message must | |
1082 | * not exceed 1024 bytes. | |
1083 | */ | |
8efc0c15 | 1084 | |
1085 | void | |
5260325f | 1086 | packet_disconnect(const char *fmt,...) |
1087 | { | |
1088 | char buf[1024]; | |
1089 | va_list args; | |
1090 | static int disconnecting = 0; | |
1091 | if (disconnecting) /* Guard against recursive invocations. */ | |
1092 | fatal("packet_disconnect called recursively."); | |
1093 | disconnecting = 1; | |
1094 | ||
aa3378df | 1095 | /* |
1096 | * Format the message. Note that the caller must make sure the | |
1097 | * message is of limited size. | |
1098 | */ | |
5260325f | 1099 | va_start(args, fmt); |
1100 | vsnprintf(buf, sizeof(buf), fmt, args); | |
1101 | va_end(args); | |
1102 | ||
1103 | /* Send the disconnect message to the other side, and wait for it to get sent. */ | |
7e7327a1 | 1104 | if (compat20) { |
1105 | packet_start(SSH2_MSG_DISCONNECT); | |
1106 | packet_put_int(SSH2_DISCONNECT_PROTOCOL_ERROR); | |
1107 | packet_put_cstring(buf); | |
1108 | packet_put_cstring(""); | |
1109 | } else { | |
1110 | packet_start(SSH_MSG_DISCONNECT); | |
449c5ba5 | 1111 | packet_put_cstring(buf); |
7e7327a1 | 1112 | } |
5260325f | 1113 | packet_send(); |
1114 | packet_write_wait(); | |
1115 | ||
1116 | /* Stop listening for connections. */ | |
d6746a0b | 1117 | channel_close_all(); |
5260325f | 1118 | |
1119 | /* Close the connection. */ | |
1120 | packet_close(); | |
1121 | ||
1122 | /* Display the error locally and exit. */ | |
57112b5a | 1123 | log("Disconnecting: %.100s", buf); |
1124 | fatal_cleanup(); | |
8efc0c15 | 1125 | } |
1126 | ||
aa3378df | 1127 | /* Checks if there is any buffered output, and tries to write some of the output. */ |
8efc0c15 | 1128 | |
1129 | void | |
d5bb9418 | 1130 | packet_write_poll(void) |
8efc0c15 | 1131 | { |
5260325f | 1132 | int len = buffer_len(&output); |
1133 | if (len > 0) { | |
1134 | len = write(connection_out, buffer_ptr(&output), len); | |
1135 | if (len <= 0) { | |
1136 | if (errno == EAGAIN) | |
1137 | return; | |
1138 | else | |
1139 | fatal("Write failed: %.100s", strerror(errno)); | |
1140 | } | |
1141 | buffer_consume(&output, len); | |
1142 | } | |
8efc0c15 | 1143 | } |
1144 | ||
aa3378df | 1145 | /* |
1146 | * Calls packet_write_poll repeatedly until all pending output data has been | |
1147 | * written. | |
1148 | */ | |
8efc0c15 | 1149 | |
1150 | void | |
d5bb9418 | 1151 | packet_write_wait(void) |
8efc0c15 | 1152 | { |
20e04e90 | 1153 | fd_set *setp; |
1154 | ||
1155 | setp = (fd_set *)xmalloc(howmany(connection_out + 1, NFDBITS) * | |
1156 | sizeof(fd_mask)); | |
5260325f | 1157 | packet_write_poll(); |
1158 | while (packet_have_data_to_write()) { | |
20e04e90 | 1159 | memset(setp, 0, howmany(connection_out + 1, NFDBITS) * |
1160 | sizeof(fd_mask)); | |
1161 | FD_SET(connection_out, setp); | |
1162 | while (select(connection_out + 1, NULL, setp, NULL, NULL) == -1 && | |
fd193ca4 | 1163 | (errno == EAGAIN || errno == EINTR)) |
1164 | ; | |
5260325f | 1165 | packet_write_poll(); |
1166 | } | |
20e04e90 | 1167 | xfree(setp); |
8efc0c15 | 1168 | } |
1169 | ||
1170 | /* Returns true if there is buffered data to write to the connection. */ | |
1171 | ||
1172 | int | |
d5bb9418 | 1173 | packet_have_data_to_write(void) |
8efc0c15 | 1174 | { |
5260325f | 1175 | return buffer_len(&output) != 0; |
8efc0c15 | 1176 | } |
1177 | ||
1178 | /* Returns true if there is not too much data to write to the connection. */ | |
1179 | ||
1180 | int | |
d5bb9418 | 1181 | packet_not_very_much_data_to_write(void) |
8efc0c15 | 1182 | { |
5260325f | 1183 | if (interactive_mode) |
1184 | return buffer_len(&output) < 16384; | |
1185 | else | |
1186 | return buffer_len(&output) < 128 * 1024; | |
8efc0c15 | 1187 | } |
1188 | ||
1189 | /* Informs that the current session is interactive. Sets IP flags for that. */ | |
1190 | ||
1191 | void | |
b5c334cc | 1192 | packet_set_interactive(int interactive) |
8efc0c15 | 1193 | { |
b5c334cc | 1194 | static int called = 0; |
64e0e67e | 1195 | #if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN) |
b5c334cc | 1196 | int lowdelay = IPTOS_LOWDELAY; |
1197 | int throughput = IPTOS_THROUGHPUT; | |
64e0e67e | 1198 | #endif |
5260325f | 1199 | |
b5c334cc | 1200 | if (called) |
1201 | return; | |
1202 | called = 1; | |
1203 | ||
5260325f | 1204 | /* Record that we are in interactive mode. */ |
1205 | interactive_mode = interactive; | |
1206 | ||
48e671d5 | 1207 | /* Only set socket options if using a socket. */ |
1208 | if (!packet_connection_is_on_socket()) | |
5260325f | 1209 | return; |
48e671d5 | 1210 | /* |
f546c780 | 1211 | * IPTOS_LOWDELAY and IPTOS_THROUGHPUT are IPv4 only |
48e671d5 | 1212 | */ |
5260325f | 1213 | if (interactive) { |
aa3378df | 1214 | /* |
1215 | * Set IP options for an interactive connection. Use | |
1216 | * IPTOS_LOWDELAY and TCP_NODELAY. | |
1217 | */ | |
132dd316 | 1218 | #if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN) |
f546c780 | 1219 | if (packet_connection_is_ipv4()) { |
0e3c1f95 | 1220 | if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, |
db518d9b | 1221 | &lowdelay, sizeof(lowdelay)) < 0) |
0e3c1f95 | 1222 | error("setsockopt IPTOS_LOWDELAY: %.100s", |
f546c780 | 1223 | strerror(errno)); |
1224 | } | |
c04f75f1 | 1225 | #endif |
bcc0381e | 1226 | set_nodelay(connection_in); |
f546c780 | 1227 | } else if (packet_connection_is_ipv4()) { |
aa3378df | 1228 | /* |
1229 | * Set IP options for a non-interactive connection. Use | |
1230 | * IPTOS_THROUGHPUT. | |
1231 | */ | |
132dd316 | 1232 | #if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN) |
db518d9b | 1233 | if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, &throughput, |
48e671d5 | 1234 | sizeof(throughput)) < 0) |
5260325f | 1235 | error("setsockopt IPTOS_THROUGHPUT: %.100s", strerror(errno)); |
c04f75f1 | 1236 | #endif |
5260325f | 1237 | } |
8efc0c15 | 1238 | } |
1239 | ||
1240 | /* Returns true if the current connection is interactive. */ | |
1241 | ||
1242 | int | |
d5bb9418 | 1243 | packet_is_interactive(void) |
8efc0c15 | 1244 | { |
5260325f | 1245 | return interactive_mode; |
8efc0c15 | 1246 | } |
9d6b7add | 1247 | |
1248 | int | |
1249 | packet_set_maxsize(int s) | |
1250 | { | |
5260325f | 1251 | static int called = 0; |
1252 | if (called) { | |
7e7327a1 | 1253 | log("packet_set_maxsize: called twice: old %d new %d", |
1254 | max_packet_size, s); | |
5260325f | 1255 | return -1; |
1256 | } | |
1257 | if (s < 4 * 1024 || s > 1024 * 1024) { | |
1258 | log("packet_set_maxsize: bad size %d", s); | |
1259 | return -1; | |
1260 | } | |
b6350327 | 1261 | called = 1; |
76735fe3 | 1262 | debug("packet_set_maxsize: setting to %d", s); |
5260325f | 1263 | max_packet_size = s; |
1264 | return s; | |
9d6b7add | 1265 | } |
a6215e53 | 1266 | |
b4b701be | 1267 | /* roundup current message to pad bytes */ |
1268 | void | |
1269 | packet_add_padding(u_char pad) | |
1270 | { | |
1271 | extra_pad = pad; | |
1272 | } | |
1273 | ||
a6215e53 | 1274 | /* |
1275 | * 9.2. Ignored Data Message | |
cd332296 | 1276 | * |
a6215e53 | 1277 | * byte SSH_MSG_IGNORE |
1278 | * string data | |
cd332296 | 1279 | * |
a6215e53 | 1280 | * All implementations MUST understand (and ignore) this message at any |
1281 | * time (after receiving the protocol version). No implementation is | |
1282 | * required to send them. This message can be used as an additional | |
1283 | * protection measure against advanced traffic analysis techniques. | |
1284 | */ | |
95ce5599 | 1285 | void |
1286 | packet_send_ignore(int nbytes) | |
1287 | { | |
1288 | u_int32_t rand = 0; | |
1289 | int i; | |
1290 | ||
1291 | packet_start(compat20 ? SSH2_MSG_IGNORE : SSH_MSG_IGNORE); | |
a6215e53 | 1292 | packet_put_int(nbytes); |
184eed6a | 1293 | for (i = 0; i < nbytes; i++) { |
a6215e53 | 1294 | if (i % 4 == 0) |
1295 | rand = arc4random(); | |
1296 | packet_put_char(rand & 0xff); | |
1297 | rand >>= 8; | |
1298 | } | |
1299 | } |