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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" | |
a49dfdec | 40 | RCSID("$OpenBSD: packet.c,v 1.93 2002/03/24 16:01:13 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" | |
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. */ | |
e050d348 | 89 | Buffer input; |
8efc0c15 | 90 | |
91 | /* Buffer for raw output data going to the socket. */ | |
e050d348 | 92 | Buffer output; |
8efc0c15 | 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]; |
e050d348 | 118 | static u_int32_t read_seqnr = 0; |
119 | static u_int32_t send_seqnr = 0; | |
7e7327a1 | 120 | |
b4b701be | 121 | /* roundup current message to extra_pad bytes */ |
122 | static u_char extra_pad = 0; | |
123 | ||
aa3378df | 124 | /* |
125 | * Sets the descriptors used for communication. Disables encryption until | |
126 | * packet_set_encryption_key is called. | |
127 | */ | |
8efc0c15 | 128 | void |
129 | packet_set_connection(int fd_in, int fd_out) | |
130 | { | |
94ec8c6b | 131 | Cipher *none = cipher_by_name("none"); |
132 | if (none == NULL) | |
133 | fatal("packet_set_connection: cannot load cipher 'none'"); | |
5260325f | 134 | connection_in = fd_in; |
135 | connection_out = fd_out; | |
3ee832e5 | 136 | cipher_init(&send_context, none, "", 0, NULL, 0, CIPHER_ENCRYPT); |
137 | cipher_init(&receive_context, none, "", 0, NULL, 0, CIPHER_DECRYPT); | |
08dcb5d7 | 138 | newkeys[MODE_IN] = newkeys[MODE_OUT] = NULL; |
5260325f | 139 | if (!initialized) { |
140 | initialized = 1; | |
141 | buffer_init(&input); | |
142 | buffer_init(&output); | |
143 | buffer_init(&outgoing_packet); | |
144 | buffer_init(&incoming_packet); | |
145 | } | |
146 | /* Kludge: arrange the close function to be called from fatal(). */ | |
147 | fatal_add_cleanup((void (*) (void *)) packet_close, NULL); | |
8efc0c15 | 148 | } |
149 | ||
48e671d5 | 150 | /* Returns 1 if remote host is connected via socket, 0 if not. */ |
151 | ||
152 | int | |
d5bb9418 | 153 | packet_connection_is_on_socket(void) |
48e671d5 | 154 | { |
155 | struct sockaddr_storage from, to; | |
156 | socklen_t fromlen, tolen; | |
157 | ||
158 | /* filedescriptors in and out are the same, so it's a socket */ | |
159 | if (connection_in == connection_out) | |
160 | return 1; | |
161 | fromlen = sizeof(from); | |
162 | memset(&from, 0, sizeof(from)); | |
9bc5ddfe | 163 | if (getpeername(connection_in, (struct sockaddr *)&from, &fromlen) < 0) |
48e671d5 | 164 | return 0; |
165 | tolen = sizeof(to); | |
166 | memset(&to, 0, sizeof(to)); | |
9bc5ddfe | 167 | if (getpeername(connection_out, (struct sockaddr *)&to, &tolen) < 0) |
48e671d5 | 168 | return 0; |
169 | if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0) | |
170 | return 0; | |
171 | if (from.ss_family != AF_INET && from.ss_family != AF_INET6) | |
172 | return 0; | |
173 | return 1; | |
174 | } | |
175 | ||
762715ce | 176 | /* |
e050d348 | 177 | * Exports an IV from the CipherContext required to export the key |
178 | * state back from the unprivileged child to the privileged parent | |
179 | * process. | |
180 | */ | |
181 | ||
182 | void | |
183 | packet_get_keyiv(int mode, u_char *iv, u_int len) | |
184 | { | |
185 | CipherContext *cc; | |
186 | ||
187 | if (mode == MODE_OUT) | |
188 | cc = &send_context; | |
189 | else | |
190 | cc = &receive_context; | |
191 | ||
192 | cipher_get_keyiv(cc, iv, len); | |
193 | } | |
194 | ||
195 | int | |
196 | packet_get_keycontext(int mode, u_char *dat) | |
197 | { | |
198 | CipherContext *cc; | |
762715ce | 199 | |
e050d348 | 200 | if (mode == MODE_OUT) |
201 | cc = &send_context; | |
202 | else | |
203 | cc = &receive_context; | |
204 | ||
205 | return (cipher_get_keycontext(cc, dat)); | |
206 | } | |
207 | ||
208 | void | |
209 | packet_set_keycontext(int mode, u_char *dat) | |
210 | { | |
211 | CipherContext *cc; | |
762715ce | 212 | |
e050d348 | 213 | if (mode == MODE_OUT) |
214 | cc = &send_context; | |
215 | else | |
216 | cc = &receive_context; | |
217 | ||
218 | cipher_set_keycontext(cc, dat); | |
219 | } | |
220 | ||
221 | int | |
222 | packet_get_keyiv_len(int mode) | |
223 | { | |
224 | CipherContext *cc; | |
225 | ||
226 | if (mode == MODE_OUT) | |
227 | cc = &send_context; | |
228 | else | |
229 | cc = &receive_context; | |
230 | ||
231 | return (cipher_get_keyiv_len(cc)); | |
232 | } | |
233 | void | |
234 | packet_set_iv(int mode, u_char *dat) | |
235 | { | |
236 | CipherContext *cc; | |
237 | ||
238 | if (mode == MODE_OUT) | |
239 | cc = &send_context; | |
240 | else | |
241 | cc = &receive_context; | |
242 | ||
243 | cipher_set_keyiv(cc, dat); | |
244 | } | |
245 | int | |
246 | packet_get_ssh1_cipher() | |
247 | { | |
248 | return (cipher_get_number(receive_context.cipher)); | |
249 | } | |
250 | ||
251 | ||
252 | u_int32_t | |
253 | packet_get_seqnr(int mode) | |
254 | { | |
255 | return (mode == MODE_IN ? read_seqnr : send_seqnr); | |
256 | } | |
257 | ||
258 | void | |
259 | packet_set_seqnr(int mode, u_int32_t seqnr) | |
260 | { | |
261 | if (mode == MODE_IN) | |
262 | read_seqnr = seqnr; | |
263 | else if (mode == MODE_OUT) | |
264 | send_seqnr = seqnr; | |
265 | else | |
266 | fatal("%s: bad mode %d", __FUNCTION__, mode); | |
267 | } | |
268 | ||
48e671d5 | 269 | /* returns 1 if connection is via ipv4 */ |
270 | ||
271 | int | |
d5bb9418 | 272 | packet_connection_is_ipv4(void) |
48e671d5 | 273 | { |
274 | struct sockaddr_storage to; | |
d45317d8 | 275 | socklen_t tolen = sizeof(to); |
48e671d5 | 276 | |
277 | memset(&to, 0, sizeof(to)); | |
278 | if (getsockname(connection_out, (struct sockaddr *)&to, &tolen) < 0) | |
279 | return 0; | |
280 | if (to.ss_family != AF_INET) | |
281 | return 0; | |
282 | return 1; | |
283 | } | |
284 | ||
8efc0c15 | 285 | /* Sets the connection into non-blocking mode. */ |
286 | ||
287 | void | |
d5bb9418 | 288 | packet_set_nonblocking(void) |
8efc0c15 | 289 | { |
5260325f | 290 | /* Set the socket into non-blocking mode. */ |
291 | if (fcntl(connection_in, F_SETFL, O_NONBLOCK) < 0) | |
292 | error("fcntl O_NONBLOCK: %.100s", strerror(errno)); | |
8efc0c15 | 293 | |
5260325f | 294 | if (connection_out != connection_in) { |
295 | if (fcntl(connection_out, F_SETFL, O_NONBLOCK) < 0) | |
296 | error("fcntl O_NONBLOCK: %.100s", strerror(errno)); | |
297 | } | |
8efc0c15 | 298 | } |
299 | ||
300 | /* Returns the socket used for reading. */ | |
301 | ||
302 | int | |
d5bb9418 | 303 | packet_get_connection_in(void) |
8efc0c15 | 304 | { |
5260325f | 305 | return connection_in; |
8efc0c15 | 306 | } |
307 | ||
308 | /* Returns the descriptor used for writing. */ | |
309 | ||
310 | int | |
d5bb9418 | 311 | packet_get_connection_out(void) |
8efc0c15 | 312 | { |
5260325f | 313 | return connection_out; |
8efc0c15 | 314 | } |
315 | ||
316 | /* Closes the connection and clears and frees internal data structures. */ | |
317 | ||
318 | void | |
d5bb9418 | 319 | packet_close(void) |
8efc0c15 | 320 | { |
5260325f | 321 | if (!initialized) |
322 | return; | |
323 | initialized = 0; | |
324 | if (connection_in == connection_out) { | |
325 | shutdown(connection_out, SHUT_RDWR); | |
326 | close(connection_out); | |
327 | } else { | |
328 | close(connection_in); | |
329 | close(connection_out); | |
330 | } | |
331 | buffer_free(&input); | |
332 | buffer_free(&output); | |
333 | buffer_free(&outgoing_packet); | |
334 | buffer_free(&incoming_packet); | |
6ba22c93 | 335 | if (compression_buffer_ready) { |
5260325f | 336 | buffer_free(&compression_buffer); |
337 | buffer_compress_uninit(); | |
338 | } | |
3ee832e5 | 339 | cipher_cleanup(&send_context); |
340 | cipher_cleanup(&receive_context); | |
8efc0c15 | 341 | } |
342 | ||
343 | /* Sets remote side protocol flags. */ | |
344 | ||
345 | void | |
1e3b8b07 | 346 | packet_set_protocol_flags(u_int protocol_flags) |
8efc0c15 | 347 | { |
5260325f | 348 | remote_protocol_flags = protocol_flags; |
8efc0c15 | 349 | } |
350 | ||
351 | /* Returns the remote protocol flags set earlier by the above function. */ | |
352 | ||
1e3b8b07 | 353 | u_int |
d5bb9418 | 354 | packet_get_protocol_flags(void) |
8efc0c15 | 355 | { |
5260325f | 356 | return remote_protocol_flags; |
8efc0c15 | 357 | } |
358 | ||
aa3378df | 359 | /* |
360 | * Starts packet compression from the next packet on in both directions. | |
361 | * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip. | |
362 | */ | |
8efc0c15 | 363 | |
396c147e | 364 | static void |
365 | packet_init_compression(void) | |
6ba22c93 | 366 | { |
367 | if (compression_buffer_ready == 1) | |
368 | return; | |
369 | compression_buffer_ready = 1; | |
370 | buffer_init(&compression_buffer); | |
371 | } | |
372 | ||
8efc0c15 | 373 | void |
374 | packet_start_compression(int level) | |
375 | { | |
08dcb5d7 | 376 | if (packet_compression && !compat20) |
5260325f | 377 | fatal("Compression already enabled."); |
378 | packet_compression = 1; | |
6ba22c93 | 379 | packet_init_compression(); |
380 | buffer_compress_init_send(level); | |
381 | buffer_compress_init_recv(); | |
8efc0c15 | 382 | } |
383 | ||
aa3378df | 384 | /* |
385 | * Causes any further packets to be encrypted using the given key. The same | |
386 | * key is used for both sending and reception. However, both directions are | |
387 | * encrypted independently of each other. | |
388 | */ | |
8efc0c15 | 389 | void |
1e3b8b07 | 390 | packet_set_encryption_key(const u_char *key, u_int keylen, |
94ec8c6b | 391 | int number) |
8efc0c15 | 392 | { |
94ec8c6b | 393 | Cipher *cipher = cipher_by_number(number); |
394 | if (cipher == NULL) | |
395 | fatal("packet_set_encryption_key: unknown cipher number %d", number); | |
7e7327a1 | 396 | if (keylen < 20) |
94ec8c6b | 397 | fatal("packet_set_encryption_key: keylen too small: %d", keylen); |
3ee832e5 | 398 | cipher_init(&send_context, cipher, key, keylen, NULL, 0, CIPHER_ENCRYPT); |
399 | cipher_init(&receive_context, cipher, key, keylen, NULL, 0, CIPHER_DECRYPT); | |
8efc0c15 | 400 | } |
401 | ||
08dcb5d7 | 402 | /* Start constructing a packet to send. */ |
8efc0c15 | 403 | void |
08dcb5d7 | 404 | packet_start(u_char type) |
8efc0c15 | 405 | { |
08dcb5d7 | 406 | u_char buf[9]; |
407 | int len; | |
7e7327a1 | 408 | |
12bf85ed | 409 | DBG(debug("packet_start[%d]", type)); |
08dcb5d7 | 410 | len = compat20 ? 6 : 9; |
411 | memset(buf, 0, len - 1); | |
412 | buf[len - 1] = type; | |
413 | buffer_clear(&outgoing_packet); | |
414 | buffer_append(&outgoing_packet, buf, len); | |
7e7327a1 | 415 | } |
416 | ||
08dcb5d7 | 417 | /* Append payload. */ |
8efc0c15 | 418 | void |
419 | packet_put_char(int value) | |
420 | { | |
5260325f | 421 | char ch = value; |
422 | buffer_append(&outgoing_packet, &ch, 1); | |
8efc0c15 | 423 | } |
8efc0c15 | 424 | void |
1e3b8b07 | 425 | packet_put_int(u_int value) |
8efc0c15 | 426 | { |
5260325f | 427 | buffer_put_int(&outgoing_packet, value); |
8efc0c15 | 428 | } |
8efc0c15 | 429 | void |
6c0fa2b1 | 430 | packet_put_string(const void *buf, u_int len) |
8efc0c15 | 431 | { |
5260325f | 432 | buffer_put_string(&outgoing_packet, buf, len); |
8efc0c15 | 433 | } |
7e7327a1 | 434 | void |
435 | packet_put_cstring(const char *str) | |
436 | { | |
449c5ba5 | 437 | buffer_put_cstring(&outgoing_packet, str); |
7e7327a1 | 438 | } |
7e7327a1 | 439 | void |
6c0fa2b1 | 440 | packet_put_raw(const void *buf, u_int len) |
7e7327a1 | 441 | { |
442 | buffer_append(&outgoing_packet, buf, len); | |
443 | } | |
8efc0c15 | 444 | void |
5260325f | 445 | packet_put_bignum(BIGNUM * value) |
8efc0c15 | 446 | { |
5260325f | 447 | buffer_put_bignum(&outgoing_packet, value); |
8efc0c15 | 448 | } |
7e7327a1 | 449 | void |
450 | packet_put_bignum2(BIGNUM * value) | |
451 | { | |
452 | buffer_put_bignum2(&outgoing_packet, value); | |
453 | } | |
8efc0c15 | 454 | |
aa3378df | 455 | /* |
456 | * Finalizes and sends the packet. If the encryption key has been set, | |
457 | * encrypts the packet before sending. | |
458 | */ | |
5260325f | 459 | |
396c147e | 460 | static void |
5ca51e19 | 461 | packet_send1(void) |
8efc0c15 | 462 | { |
a318bbf4 | 463 | u_char buf[8], *cp; |
5260325f | 464 | int i, padding, len; |
1e3b8b07 | 465 | u_int checksum; |
5260325f | 466 | u_int32_t rand = 0; |
467 | ||
aa3378df | 468 | /* |
469 | * If using packet compression, compress the payload of the outgoing | |
470 | * packet. | |
471 | */ | |
5260325f | 472 | if (packet_compression) { |
473 | buffer_clear(&compression_buffer); | |
474 | /* Skip padding. */ | |
475 | buffer_consume(&outgoing_packet, 8); | |
476 | /* padding */ | |
477 | buffer_append(&compression_buffer, "\0\0\0\0\0\0\0\0", 8); | |
478 | buffer_compress(&outgoing_packet, &compression_buffer); | |
479 | buffer_clear(&outgoing_packet); | |
480 | buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer), | |
184eed6a | 481 | buffer_len(&compression_buffer)); |
5260325f | 482 | } |
483 | /* Compute packet length without padding (add checksum, remove padding). */ | |
484 | len = buffer_len(&outgoing_packet) + 4 - 8; | |
485 | ||
1d1ffb87 | 486 | /* Insert padding. Initialized to zero in packet_start1() */ |
5260325f | 487 | padding = 8 - len % 8; |
3ee832e5 | 488 | if (!send_context.plaintext) { |
5260325f | 489 | cp = buffer_ptr(&outgoing_packet); |
490 | for (i = 0; i < padding; i++) { | |
491 | if (i % 4 == 0) | |
492 | rand = arc4random(); | |
493 | cp[7 - i] = rand & 0xff; | |
494 | rand >>= 8; | |
495 | } | |
496 | } | |
497 | buffer_consume(&outgoing_packet, 8 - padding); | |
498 | ||
499 | /* Add check bytes. */ | |
20905a8e | 500 | checksum = ssh_crc32(buffer_ptr(&outgoing_packet), |
2e73a022 | 501 | buffer_len(&outgoing_packet)); |
5260325f | 502 | PUT_32BIT(buf, checksum); |
503 | buffer_append(&outgoing_packet, buf, 4); | |
8efc0c15 | 504 | |
505 | #ifdef PACKET_DEBUG | |
5260325f | 506 | fprintf(stderr, "packet_send plain: "); |
507 | buffer_dump(&outgoing_packet); | |
8efc0c15 | 508 | #endif |
509 | ||
5260325f | 510 | /* Append to output. */ |
511 | PUT_32BIT(buf, len); | |
512 | buffer_append(&output, buf, 4); | |
6c0fa2b1 | 513 | cp = buffer_append_space(&output, buffer_len(&outgoing_packet)); |
3ee832e5 | 514 | cipher_crypt(&send_context, cp, buffer_ptr(&outgoing_packet), |
184eed6a | 515 | buffer_len(&outgoing_packet)); |
5260325f | 516 | |
8efc0c15 | 517 | #ifdef PACKET_DEBUG |
5260325f | 518 | fprintf(stderr, "encrypted: "); |
519 | buffer_dump(&output); | |
8efc0c15 | 520 | #endif |
521 | ||
5260325f | 522 | buffer_clear(&outgoing_packet); |
8efc0c15 | 523 | |
aa3378df | 524 | /* |
525 | * Note that the packet is now only buffered in output. It won\'t be | |
526 | * actually sent until packet_write_wait or packet_write_poll is | |
527 | * called. | |
528 | */ | |
8efc0c15 | 529 | } |
530 | ||
e050d348 | 531 | void |
d1ac6175 | 532 | set_newkeys(int mode) |
533 | { | |
534 | Enc *enc; | |
535 | Mac *mac; | |
536 | Comp *comp; | |
537 | CipherContext *cc; | |
3ee832e5 | 538 | int encrypt; |
d1ac6175 | 539 | |
540 | debug("newkeys: mode %d", mode); | |
541 | ||
3ee832e5 | 542 | if (mode == MODE_OUT) { |
543 | cc = &send_context; | |
544 | encrypt = CIPHER_ENCRYPT; | |
545 | } else { | |
546 | cc = &receive_context; | |
547 | encrypt = CIPHER_DECRYPT; | |
548 | } | |
d1ac6175 | 549 | if (newkeys[mode] != NULL) { |
550 | debug("newkeys: rekeying"); | |
3ee832e5 | 551 | cipher_cleanup(cc); |
a7ca6275 | 552 | enc = &newkeys[mode]->enc; |
553 | mac = &newkeys[mode]->mac; | |
554 | comp = &newkeys[mode]->comp; | |
cd332296 | 555 | memset(mac->key, 0, mac->key_len); |
a7ca6275 | 556 | xfree(enc->name); |
557 | xfree(enc->iv); | |
558 | xfree(enc->key); | |
559 | xfree(mac->name); | |
560 | xfree(mac->key); | |
561 | xfree(comp->name); | |
d8ee838b | 562 | xfree(newkeys[mode]); |
d1ac6175 | 563 | } |
564 | newkeys[mode] = kex_get_newkeys(mode); | |
565 | if (newkeys[mode] == NULL) | |
566 | fatal("newkeys: no keys for mode %d", mode); | |
567 | enc = &newkeys[mode]->enc; | |
568 | mac = &newkeys[mode]->mac; | |
569 | comp = &newkeys[mode]->comp; | |
570 | if (mac->md != NULL) | |
571 | mac->enabled = 1; | |
572 | DBG(debug("cipher_init_context: %d", mode)); | |
3ee832e5 | 573 | cipher_init(cc, enc->cipher, enc->key, enc->key_len, |
574 | enc->iv, enc->block_size, encrypt); | |
e050d348 | 575 | /* Deleting the keys does not gain extra security */ |
576 | /* memset(enc->iv, 0, enc->block_size); | |
577 | memset(enc->key, 0, enc->key_len); */ | |
d1ac6175 | 578 | if (comp->type != 0 && comp->enabled == 0) { |
6ba22c93 | 579 | packet_init_compression(); |
580 | if (mode == MODE_OUT) | |
581 | buffer_compress_init_send(6); | |
582 | else | |
583 | buffer_compress_init_recv(); | |
d1ac6175 | 584 | comp->enabled = 1; |
d1ac6175 | 585 | } |
586 | } | |
587 | ||
7e7327a1 | 588 | /* |
589 | * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue) | |
590 | */ | |
396c147e | 591 | static void |
5ca51e19 | 592 | packet_send2(void) |
7e7327a1 | 593 | { |
a318bbf4 | 594 | u_char type, *cp, *macbuf = NULL; |
b4b701be | 595 | u_char padlen, pad; |
1e3b8b07 | 596 | u_int packet_length = 0; |
b4b701be | 597 | u_int i, len; |
7e7327a1 | 598 | u_int32_t rand = 0; |
7e7327a1 | 599 | Enc *enc = NULL; |
600 | Mac *mac = NULL; | |
601 | Comp *comp = NULL; | |
602 | int block_size; | |
603 | ||
d1ac6175 | 604 | if (newkeys[MODE_OUT] != NULL) { |
605 | enc = &newkeys[MODE_OUT]->enc; | |
606 | mac = &newkeys[MODE_OUT]->mac; | |
607 | comp = &newkeys[MODE_OUT]->comp; | |
7e7327a1 | 608 | } |
3ee832e5 | 609 | block_size = enc ? enc->block_size : 8; |
7e7327a1 | 610 | |
a318bbf4 | 611 | cp = buffer_ptr(&outgoing_packet); |
612 | type = cp[5]; | |
7e7327a1 | 613 | |
614 | #ifdef PACKET_DEBUG | |
615 | fprintf(stderr, "plain: "); | |
616 | buffer_dump(&outgoing_packet); | |
617 | #endif | |
618 | ||
619 | if (comp && comp->enabled) { | |
620 | len = buffer_len(&outgoing_packet); | |
621 | /* skip header, compress only payload */ | |
622 | buffer_consume(&outgoing_packet, 5); | |
623 | buffer_clear(&compression_buffer); | |
624 | buffer_compress(&outgoing_packet, &compression_buffer); | |
625 | buffer_clear(&outgoing_packet); | |
626 | buffer_append(&outgoing_packet, "\0\0\0\0\0", 5); | |
627 | buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer), | |
628 | buffer_len(&compression_buffer)); | |
629 | DBG(debug("compression: raw %d compressed %d", len, | |
630 | buffer_len(&outgoing_packet))); | |
631 | } | |
632 | ||
633 | /* sizeof (packet_len + pad_len + payload) */ | |
634 | len = buffer_len(&outgoing_packet); | |
635 | ||
636 | /* | |
637 | * calc size of padding, alloc space, get random data, | |
638 | * minimum padding is 4 bytes | |
639 | */ | |
640 | padlen = block_size - (len % block_size); | |
641 | if (padlen < 4) | |
642 | padlen += block_size; | |
b4b701be | 643 | if (extra_pad) { |
644 | /* will wrap if extra_pad+padlen > 255 */ | |
645 | extra_pad = roundup(extra_pad, block_size); | |
646 | pad = extra_pad - ((len + padlen) % extra_pad); | |
a49dfdec | 647 | debug3("packet_send2: adding %d (len %d padlen %d extra_pad %d)", |
b4b701be | 648 | pad, len, padlen, extra_pad); |
649 | padlen += pad; | |
650 | extra_pad = 0; | |
651 | } | |
6c0fa2b1 | 652 | cp = buffer_append_space(&outgoing_packet, padlen); |
3ee832e5 | 653 | if (enc && !send_context.plaintext) { |
1d1ffb87 | 654 | /* random padding */ |
7e7327a1 | 655 | for (i = 0; i < padlen; i++) { |
656 | if (i % 4 == 0) | |
657 | rand = arc4random(); | |
658 | cp[i] = rand & 0xff; | |
6e18cb71 | 659 | rand >>= 8; |
7e7327a1 | 660 | } |
1d1ffb87 | 661 | } else { |
662 | /* clear padding */ | |
663 | memset(cp, 0, padlen); | |
7e7327a1 | 664 | } |
665 | /* packet_length includes payload, padding and padding length field */ | |
666 | packet_length = buffer_len(&outgoing_packet) - 4; | |
a318bbf4 | 667 | cp = buffer_ptr(&outgoing_packet); |
668 | PUT_32BIT(cp, packet_length); | |
669 | cp[4] = padlen; | |
7e7327a1 | 670 | DBG(debug("send: len %d (includes padlen %d)", packet_length+4, padlen)); |
671 | ||
672 | /* compute MAC over seqnr and packet(length fields, payload, padding) */ | |
673 | if (mac && mac->enabled) { | |
e050d348 | 674 | macbuf = mac_compute(mac, send_seqnr, |
20905a8e | 675 | buffer_ptr(&outgoing_packet), |
b2552997 | 676 | buffer_len(&outgoing_packet)); |
e050d348 | 677 | DBG(debug("done calc MAC out #%d", send_seqnr)); |
7e7327a1 | 678 | } |
679 | /* encrypt packet and append to output buffer. */ | |
6c0fa2b1 | 680 | cp = buffer_append_space(&output, buffer_len(&outgoing_packet)); |
3ee832e5 | 681 | cipher_crypt(&send_context, cp, buffer_ptr(&outgoing_packet), |
7e7327a1 | 682 | buffer_len(&outgoing_packet)); |
683 | /* append unencrypted MAC */ | |
684 | if (mac && mac->enabled) | |
685 | buffer_append(&output, (char *)macbuf, mac->mac_len); | |
686 | #ifdef PACKET_DEBUG | |
687 | fprintf(stderr, "encrypted: "); | |
688 | buffer_dump(&output); | |
689 | #endif | |
6ae2364d | 690 | /* increment sequence number for outgoing packets */ |
e050d348 | 691 | if (++send_seqnr == 0) |
6ae2364d | 692 | log("outgoing seqnr wraps around"); |
7e7327a1 | 693 | buffer_clear(&outgoing_packet); |
694 | ||
d1ac6175 | 695 | if (type == SSH2_MSG_NEWKEYS) |
696 | set_newkeys(MODE_OUT); | |
7e7327a1 | 697 | } |
698 | ||
699 | void | |
d5bb9418 | 700 | packet_send(void) |
7e7327a1 | 701 | { |
08dcb5d7 | 702 | if (compat20) |
7e7327a1 | 703 | packet_send2(); |
704 | else | |
705 | packet_send1(); | |
706 | DBG(debug("packet_send done")); | |
707 | } | |
708 | ||
aa3378df | 709 | /* |
710 | * Waits until a packet has been received, and returns its type. Note that | |
711 | * no other data is processed until this returns, so this function should not | |
712 | * be used during the interactive session. | |
713 | */ | |
8efc0c15 | 714 | |
715 | int | |
54a5250f | 716 | packet_read_seqnr(u_int32_t *seqnr_p) |
8efc0c15 | 717 | { |
5260325f | 718 | int type, len; |
20e04e90 | 719 | fd_set *setp; |
5260325f | 720 | char buf[8192]; |
7e7327a1 | 721 | DBG(debug("packet_read()")); |
5260325f | 722 | |
20e04e90 | 723 | setp = (fd_set *)xmalloc(howmany(connection_in+1, NFDBITS) * |
724 | sizeof(fd_mask)); | |
725 | ||
5260325f | 726 | /* Since we are blocking, ensure that all written packets have been sent. */ |
727 | packet_write_wait(); | |
728 | ||
729 | /* Stay in the loop until we have received a complete packet. */ | |
730 | for (;;) { | |
731 | /* Try to read a packet from the buffer. */ | |
54a5250f | 732 | type = packet_read_poll_seqnr(seqnr_p); |
08dcb5d7 | 733 | if (!compat20 && ( |
1d1ffb87 | 734 | type == SSH_SMSG_SUCCESS |
5260325f | 735 | || type == SSH_SMSG_FAILURE |
736 | || type == SSH_CMSG_EOF | |
1d1ffb87 | 737 | || type == SSH_CMSG_EXIT_CONFIRMATION)) |
95500969 | 738 | packet_check_eom(); |
5260325f | 739 | /* If we got a packet, return it. */ |
20e04e90 | 740 | if (type != SSH_MSG_NONE) { |
741 | xfree(setp); | |
5260325f | 742 | return type; |
20e04e90 | 743 | } |
aa3378df | 744 | /* |
745 | * Otherwise, wait for some data to arrive, add it to the | |
746 | * buffer, and try again. | |
747 | */ | |
20e04e90 | 748 | memset(setp, 0, howmany(connection_in + 1, NFDBITS) * |
749 | sizeof(fd_mask)); | |
750 | FD_SET(connection_in, setp); | |
aa3378df | 751 | |
5260325f | 752 | /* Wait for some data to arrive. */ |
20e04e90 | 753 | while (select(connection_in + 1, setp, NULL, NULL, NULL) == -1 && |
fd193ca4 | 754 | (errno == EAGAIN || errno == EINTR)) |
755 | ; | |
aa3378df | 756 | |
5260325f | 757 | /* Read data from the socket. */ |
758 | len = read(connection_in, buf, sizeof(buf)); | |
89cafde6 | 759 | if (len == 0) { |
760 | log("Connection closed by %.200s", get_remote_ipaddr()); | |
761 | fatal_cleanup(); | |
762 | } | |
5260325f | 763 | if (len < 0) |
764 | fatal("Read from socket failed: %.100s", strerror(errno)); | |
765 | /* Append it to the buffer. */ | |
766 | packet_process_incoming(buf, len); | |
767 | } | |
768 | /* NOTREACHED */ | |
8efc0c15 | 769 | } |
770 | ||
24ca6821 | 771 | int |
54a5250f | 772 | packet_read(void) |
24ca6821 | 773 | { |
54a5250f | 774 | return packet_read_seqnr(NULL); |
24ca6821 | 775 | } |
776 | ||
aa3378df | 777 | /* |
778 | * Waits until a packet has been received, verifies that its type matches | |
779 | * that given, and gives a fatal error and exits if there is a mismatch. | |
780 | */ | |
8efc0c15 | 781 | |
782 | void | |
54a5250f | 783 | packet_read_expect(int expected_type) |
8efc0c15 | 784 | { |
5260325f | 785 | int type; |
8efc0c15 | 786 | |
54a5250f | 787 | type = packet_read(); |
5260325f | 788 | if (type != expected_type) |
789 | packet_disconnect("Protocol error: expected packet type %d, got %d", | |
7e7327a1 | 790 | expected_type, type); |
8efc0c15 | 791 | } |
792 | ||
793 | /* Checks if a full packet is available in the data received so far via | |
5260325f | 794 | * packet_process_incoming. If so, reads the packet; otherwise returns |
795 | * SSH_MSG_NONE. This does not wait for data from the connection. | |
796 | * | |
797 | * SSH_MSG_DISCONNECT is handled specially here. Also, | |
798 | * SSH_MSG_IGNORE messages are skipped by this function and are never returned | |
799 | * to higher levels. | |
5260325f | 800 | */ |
8efc0c15 | 801 | |
396c147e | 802 | static int |
54a5250f | 803 | packet_read_poll1(void) |
8efc0c15 | 804 | { |
1e3b8b07 | 805 | u_int len, padded_len; |
a318bbf4 | 806 | u_char *cp, type; |
1e3b8b07 | 807 | u_int checksum, stored_checksum; |
5260325f | 808 | |
5260325f | 809 | /* Check if input size is less than minimum packet size. */ |
810 | if (buffer_len(&input) < 4 + 8) | |
811 | return SSH_MSG_NONE; | |
812 | /* Get length of incoming packet. */ | |
a318bbf4 | 813 | cp = buffer_ptr(&input); |
814 | len = GET_32BIT(cp); | |
5260325f | 815 | if (len < 1 + 2 + 2 || len > 256 * 1024) |
816 | packet_disconnect("Bad packet length %d.", len); | |
817 | padded_len = (len + 8) & ~7; | |
818 | ||
819 | /* Check if the packet has been entirely received. */ | |
820 | if (buffer_len(&input) < 4 + padded_len) | |
821 | return SSH_MSG_NONE; | |
822 | ||
823 | /* The entire packet is in buffer. */ | |
824 | ||
825 | /* Consume packet length. */ | |
826 | buffer_consume(&input, 4); | |
827 | ||
08dcb5d7 | 828 | /* |
829 | * Cryptographic attack detector for ssh | |
830 | * (C)1998 CORE-SDI, Buenos Aires Argentina | |
831 | * Ariel Futoransky(futo@core-sdi.com) | |
832 | */ | |
3ee832e5 | 833 | if (!receive_context.plaintext && |
08dcb5d7 | 834 | detect_attack(buffer_ptr(&input), padded_len, NULL) == DEATTACK_DETECTED) |
835 | packet_disconnect("crc32 compensation attack: network attack detected"); | |
836 | ||
837 | /* Decrypt data to incoming_packet. */ | |
5260325f | 838 | buffer_clear(&incoming_packet); |
6c0fa2b1 | 839 | cp = buffer_append_space(&incoming_packet, padded_len); |
3ee832e5 | 840 | cipher_crypt(&receive_context, cp, buffer_ptr(&input), padded_len); |
08dcb5d7 | 841 | |
5260325f | 842 | buffer_consume(&input, padded_len); |
8efc0c15 | 843 | |
844 | #ifdef PACKET_DEBUG | |
5260325f | 845 | fprintf(stderr, "read_poll plain: "); |
846 | buffer_dump(&incoming_packet); | |
8efc0c15 | 847 | #endif |
5260325f | 848 | |
849 | /* Compute packet checksum. */ | |
20905a8e | 850 | checksum = ssh_crc32(buffer_ptr(&incoming_packet), |
7e7327a1 | 851 | buffer_len(&incoming_packet) - 4); |
5260325f | 852 | |
853 | /* Skip padding. */ | |
854 | buffer_consume(&incoming_packet, 8 - len % 8); | |
855 | ||
856 | /* Test check bytes. */ | |
5260325f | 857 | if (len != buffer_len(&incoming_packet)) |
24ca6821 | 858 | packet_disconnect("packet_read_poll1: len %d != buffer_len %d.", |
7e7327a1 | 859 | len, buffer_len(&incoming_packet)); |
5260325f | 860 | |
a318bbf4 | 861 | cp = (u_char *)buffer_ptr(&incoming_packet) + len - 4; |
862 | stored_checksum = GET_32BIT(cp); | |
5260325f | 863 | if (checksum != stored_checksum) |
864 | packet_disconnect("Corrupted check bytes on input."); | |
865 | buffer_consume_end(&incoming_packet, 4); | |
866 | ||
5260325f | 867 | if (packet_compression) { |
868 | buffer_clear(&compression_buffer); | |
869 | buffer_uncompress(&incoming_packet, &compression_buffer); | |
870 | buffer_clear(&incoming_packet); | |
871 | buffer_append(&incoming_packet, buffer_ptr(&compression_buffer), | |
7e7327a1 | 872 | buffer_len(&compression_buffer)); |
5260325f | 873 | } |
08dcb5d7 | 874 | type = buffer_get_char(&incoming_packet); |
08dcb5d7 | 875 | return type; |
5260325f | 876 | } |
877 | ||
396c147e | 878 | static int |
54a5250f | 879 | packet_read_poll2(u_int32_t *seqnr_p) |
7e7327a1 | 880 | { |
b2552997 | 881 | static u_int packet_length = 0; |
1e3b8b07 | 882 | u_int padlen, need; |
a318bbf4 | 883 | u_char *macbuf, *cp, type; |
7e7327a1 | 884 | int maclen, block_size; |
885 | Enc *enc = NULL; | |
886 | Mac *mac = NULL; | |
887 | Comp *comp = NULL; | |
888 | ||
d1ac6175 | 889 | if (newkeys[MODE_IN] != NULL) { |
890 | enc = &newkeys[MODE_IN]->enc; | |
891 | mac = &newkeys[MODE_IN]->mac; | |
892 | comp = &newkeys[MODE_IN]->comp; | |
7e7327a1 | 893 | } |
894 | maclen = mac && mac->enabled ? mac->mac_len : 0; | |
3ee832e5 | 895 | block_size = enc ? enc->block_size : 8; |
7e7327a1 | 896 | |
897 | if (packet_length == 0) { | |
898 | /* | |
899 | * check if input size is less than the cipher block size, | |
900 | * decrypt first block and extract length of incoming packet | |
901 | */ | |
902 | if (buffer_len(&input) < block_size) | |
903 | return SSH_MSG_NONE; | |
904 | buffer_clear(&incoming_packet); | |
6c0fa2b1 | 905 | cp = buffer_append_space(&incoming_packet, block_size); |
3ee832e5 | 906 | cipher_crypt(&receive_context, cp, buffer_ptr(&input), |
7e7327a1 | 907 | block_size); |
a318bbf4 | 908 | cp = buffer_ptr(&incoming_packet); |
909 | packet_length = GET_32BIT(cp); | |
7e7327a1 | 910 | if (packet_length < 1 + 4 || packet_length > 256 * 1024) { |
911 | buffer_dump(&incoming_packet); | |
912 | packet_disconnect("Bad packet length %d.", packet_length); | |
913 | } | |
914 | DBG(debug("input: packet len %d", packet_length+4)); | |
915 | buffer_consume(&input, block_size); | |
916 | } | |
917 | /* we have a partial packet of block_size bytes */ | |
918 | need = 4 + packet_length - block_size; | |
919 | DBG(debug("partial packet %d, need %d, maclen %d", block_size, | |
920 | need, maclen)); | |
921 | if (need % block_size != 0) | |
922 | fatal("padding error: need %d block %d mod %d", | |
923 | need, block_size, need % block_size); | |
924 | /* | |
925 | * check if the entire packet has been received and | |
926 | * decrypt into incoming_packet | |
927 | */ | |
928 | if (buffer_len(&input) < need + maclen) | |
929 | return SSH_MSG_NONE; | |
930 | #ifdef PACKET_DEBUG | |
931 | fprintf(stderr, "read_poll enc/full: "); | |
932 | buffer_dump(&input); | |
933 | #endif | |
6c0fa2b1 | 934 | cp = buffer_append_space(&incoming_packet, need); |
3ee832e5 | 935 | cipher_crypt(&receive_context, cp, buffer_ptr(&input), need); |
7e7327a1 | 936 | buffer_consume(&input, need); |
937 | /* | |
938 | * compute MAC over seqnr and packet, | |
939 | * increment sequence number for incoming packet | |
940 | */ | |
6ae2364d | 941 | if (mac && mac->enabled) { |
e050d348 | 942 | macbuf = mac_compute(mac, read_seqnr, |
20905a8e | 943 | buffer_ptr(&incoming_packet), |
b2552997 | 944 | buffer_len(&incoming_packet)); |
7e7327a1 | 945 | if (memcmp(macbuf, buffer_ptr(&input), mac->mac_len) != 0) |
94ec8c6b | 946 | packet_disconnect("Corrupted MAC on input."); |
e050d348 | 947 | DBG(debug("MAC #%d ok", read_seqnr)); |
7e7327a1 | 948 | buffer_consume(&input, mac->mac_len); |
949 | } | |
24ca6821 | 950 | if (seqnr_p != NULL) |
e050d348 | 951 | *seqnr_p = read_seqnr; |
952 | if (++read_seqnr == 0) | |
6ae2364d | 953 | log("incoming seqnr wraps around"); |
7e7327a1 | 954 | |
955 | /* get padlen */ | |
6c0fa2b1 | 956 | cp = buffer_ptr(&incoming_packet); |
a318bbf4 | 957 | padlen = cp[4]; |
7e7327a1 | 958 | DBG(debug("input: padlen %d", padlen)); |
959 | if (padlen < 4) | |
960 | packet_disconnect("Corrupted padlen %d on input.", padlen); | |
961 | ||
962 | /* skip packet size + padlen, discard padding */ | |
963 | buffer_consume(&incoming_packet, 4 + 1); | |
964 | buffer_consume_end(&incoming_packet, padlen); | |
965 | ||
966 | DBG(debug("input: len before de-compress %d", buffer_len(&incoming_packet))); | |
967 | if (comp && comp->enabled) { | |
968 | buffer_clear(&compression_buffer); | |
969 | buffer_uncompress(&incoming_packet, &compression_buffer); | |
970 | buffer_clear(&incoming_packet); | |
971 | buffer_append(&incoming_packet, buffer_ptr(&compression_buffer), | |
972 | buffer_len(&compression_buffer)); | |
973 | DBG(debug("input: len after de-compress %d", buffer_len(&incoming_packet))); | |
974 | } | |
975 | /* | |
976 | * get packet type, implies consume. | |
977 | * return length of payload (without type field) | |
978 | */ | |
08dcb5d7 | 979 | type = buffer_get_char(&incoming_packet); |
d1ac6175 | 980 | if (type == SSH2_MSG_NEWKEYS) |
981 | set_newkeys(MODE_IN); | |
7e7327a1 | 982 | #ifdef PACKET_DEBUG |
12bf85ed | 983 | fprintf(stderr, "read/plain[%d]:\r\n", type); |
7e7327a1 | 984 | buffer_dump(&incoming_packet); |
985 | #endif | |
08dcb5d7 | 986 | /* reset for next packet */ |
987 | packet_length = 0; | |
988 | return type; | |
7e7327a1 | 989 | } |
990 | ||
991 | int | |
54a5250f | 992 | packet_read_poll_seqnr(u_int32_t *seqnr_p) |
7e7327a1 | 993 | { |
5a5f4c37 | 994 | int reason, seqnr; |
08dcb5d7 | 995 | u_char type; |
7e7327a1 | 996 | char *msg; |
7e7327a1 | 997 | |
08dcb5d7 | 998 | for (;;) { |
999 | if (compat20) { | |
54a5250f | 1000 | type = packet_read_poll2(seqnr_p); |
08dcb5d7 | 1001 | if (type) |
7e7327a1 | 1002 | DBG(debug("received packet type %d", type)); |
6aacefa7 | 1003 | switch (type) { |
7e7327a1 | 1004 | case SSH2_MSG_IGNORE: |
1005 | break; | |
1006 | case SSH2_MSG_DEBUG: | |
1007 | packet_get_char(); | |
1008 | msg = packet_get_string(NULL); | |
1009 | debug("Remote: %.900s", msg); | |
1010 | xfree(msg); | |
1011 | msg = packet_get_string(NULL); | |
1012 | xfree(msg); | |
1013 | break; | |
1014 | case SSH2_MSG_DISCONNECT: | |
1015 | reason = packet_get_int(); | |
1016 | msg = packet_get_string(NULL); | |
7c49df64 | 1017 | log("Received disconnect from %s: %d: %.400s", get_remote_ipaddr(), |
1018 | reason, msg); | |
7e7327a1 | 1019 | xfree(msg); |
1020 | fatal_cleanup(); | |
1021 | break; | |
5a5f4c37 | 1022 | case SSH2_MSG_UNIMPLEMENTED: |
1023 | seqnr = packet_get_int(); | |
1024 | debug("Received SSH2_MSG_UNIMPLEMENTED for %d", seqnr); | |
1025 | break; | |
7e7327a1 | 1026 | default: |
1027 | return type; | |
1028 | break; | |
2b87da3b | 1029 | } |
7e7327a1 | 1030 | } else { |
54a5250f | 1031 | type = packet_read_poll1(); |
6aacefa7 | 1032 | switch (type) { |
7e7327a1 | 1033 | case SSH_MSG_IGNORE: |
1034 | break; | |
1035 | case SSH_MSG_DEBUG: | |
1036 | msg = packet_get_string(NULL); | |
1037 | debug("Remote: %.900s", msg); | |
1038 | xfree(msg); | |
1039 | break; | |
1040 | case SSH_MSG_DISCONNECT: | |
1041 | msg = packet_get_string(NULL); | |
7c49df64 | 1042 | log("Received disconnect from %s: %.400s", get_remote_ipaddr(), |
1043 | msg); | |
7e7327a1 | 1044 | fatal_cleanup(); |
1045 | xfree(msg); | |
1046 | break; | |
1047 | default: | |
08dcb5d7 | 1048 | if (type) |
7e7327a1 | 1049 | DBG(debug("received packet type %d", type)); |
1050 | return type; | |
1051 | break; | |
2b87da3b | 1052 | } |
7e7327a1 | 1053 | } |
1054 | } | |
1055 | } | |
1056 | ||
24ca6821 | 1057 | int |
54a5250f | 1058 | packet_read_poll(void) |
24ca6821 | 1059 | { |
54a5250f | 1060 | return packet_read_poll_seqnr(NULL); |
24ca6821 | 1061 | } |
1062 | ||
aa3378df | 1063 | /* |
1064 | * Buffers the given amount of input characters. This is intended to be used | |
1065 | * together with packet_read_poll. | |
1066 | */ | |
8efc0c15 | 1067 | |
1068 | void | |
1e3b8b07 | 1069 | packet_process_incoming(const char *buf, u_int len) |
8efc0c15 | 1070 | { |
5260325f | 1071 | buffer_append(&input, buf, len); |
8efc0c15 | 1072 | } |
1073 | ||
1074 | /* Returns a character from the packet. */ | |
1075 | ||
1e3b8b07 | 1076 | u_int |
d5bb9418 | 1077 | packet_get_char(void) |
8efc0c15 | 1078 | { |
5260325f | 1079 | char ch; |
1080 | buffer_get(&incoming_packet, &ch, 1); | |
1e3b8b07 | 1081 | return (u_char) ch; |
8efc0c15 | 1082 | } |
1083 | ||
1084 | /* Returns an integer from the packet data. */ | |
1085 | ||
1e3b8b07 | 1086 | u_int |
d5bb9418 | 1087 | packet_get_int(void) |
8efc0c15 | 1088 | { |
5260325f | 1089 | return buffer_get_int(&incoming_packet); |
8efc0c15 | 1090 | } |
1091 | ||
aa3378df | 1092 | /* |
1093 | * Returns an arbitrary precision integer from the packet data. The integer | |
1094 | * must have been initialized before this call. | |
1095 | */ | |
8efc0c15 | 1096 | |
1097 | void | |
20b279e6 | 1098 | packet_get_bignum(BIGNUM * value) |
8efc0c15 | 1099 | { |
4ef6f649 | 1100 | buffer_get_bignum(&incoming_packet, value); |
8efc0c15 | 1101 | } |
1102 | ||
7e7327a1 | 1103 | void |
20b279e6 | 1104 | packet_get_bignum2(BIGNUM * value) |
7e7327a1 | 1105 | { |
4ef6f649 | 1106 | buffer_get_bignum2(&incoming_packet, value); |
7e7327a1 | 1107 | } |
1108 | ||
6c0fa2b1 | 1109 | void * |
7e7327a1 | 1110 | packet_get_raw(int *length_ptr) |
1111 | { | |
1112 | int bytes = buffer_len(&incoming_packet); | |
1113 | if (length_ptr != NULL) | |
1114 | *length_ptr = bytes; | |
1115 | return buffer_ptr(&incoming_packet); | |
1116 | } | |
1117 | ||
6ae2364d | 1118 | int |
1119 | packet_remaining(void) | |
1120 | { | |
1121 | return buffer_len(&incoming_packet); | |
1122 | } | |
1123 | ||
aa3378df | 1124 | /* |
1125 | * Returns a string from the packet data. The string is allocated using | |
1126 | * xmalloc; it is the responsibility of the calling program to free it when | |
1127 | * no longer needed. The length_ptr argument may be NULL, or point to an | |
1128 | * integer into which the length of the string is stored. | |
1129 | */ | |
8efc0c15 | 1130 | |
6c0fa2b1 | 1131 | void * |
1e3b8b07 | 1132 | packet_get_string(u_int *length_ptr) |
8efc0c15 | 1133 | { |
5260325f | 1134 | return buffer_get_string(&incoming_packet, length_ptr); |
8efc0c15 | 1135 | } |
1136 | ||
aa3378df | 1137 | /* |
1138 | * Sends a diagnostic message from the server to the client. This message | |
1139 | * can be sent at any time (but not while constructing another message). The | |
1140 | * message is printed immediately, but only if the client is being executed | |
1141 | * in verbose mode. These messages are primarily intended to ease debugging | |
1142 | * authentication problems. The length of the formatted message must not | |
1143 | * exceed 1024 bytes. This will automatically call packet_write_wait. | |
1144 | */ | |
8efc0c15 | 1145 | |
1146 | void | |
5260325f | 1147 | packet_send_debug(const char *fmt,...) |
8efc0c15 | 1148 | { |
5260325f | 1149 | char buf[1024]; |
1150 | va_list args; | |
1151 | ||
f72fc97f | 1152 | if (compat20 && (datafellows & SSH_BUG_DEBUG)) |
1153 | return; | |
1154 | ||
5260325f | 1155 | va_start(args, fmt); |
1156 | vsnprintf(buf, sizeof(buf), fmt, args); | |
1157 | va_end(args); | |
1158 | ||
c4bc58eb | 1159 | if (compat20) { |
1160 | packet_start(SSH2_MSG_DEBUG); | |
1161 | packet_put_char(0); /* bool: always display */ | |
1162 | packet_put_cstring(buf); | |
1163 | packet_put_cstring(""); | |
1164 | } else { | |
1165 | packet_start(SSH_MSG_DEBUG); | |
1166 | packet_put_cstring(buf); | |
1167 | } | |
5260325f | 1168 | packet_send(); |
1169 | packet_write_wait(); | |
8efc0c15 | 1170 | } |
1171 | ||
aa3378df | 1172 | /* |
1173 | * Logs the error plus constructs and sends a disconnect packet, closes the | |
1174 | * connection, and exits. This function never returns. The error message | |
1175 | * should not contain a newline. The length of the formatted message must | |
1176 | * not exceed 1024 bytes. | |
1177 | */ | |
8efc0c15 | 1178 | |
1179 | void | |
5260325f | 1180 | packet_disconnect(const char *fmt,...) |
1181 | { | |
1182 | char buf[1024]; | |
1183 | va_list args; | |
1184 | static int disconnecting = 0; | |
1185 | if (disconnecting) /* Guard against recursive invocations. */ | |
1186 | fatal("packet_disconnect called recursively."); | |
1187 | disconnecting = 1; | |
1188 | ||
aa3378df | 1189 | /* |
1190 | * Format the message. Note that the caller must make sure the | |
1191 | * message is of limited size. | |
1192 | */ | |
5260325f | 1193 | va_start(args, fmt); |
1194 | vsnprintf(buf, sizeof(buf), fmt, args); | |
1195 | va_end(args); | |
1196 | ||
1197 | /* Send the disconnect message to the other side, and wait for it to get sent. */ | |
7e7327a1 | 1198 | if (compat20) { |
1199 | packet_start(SSH2_MSG_DISCONNECT); | |
1200 | packet_put_int(SSH2_DISCONNECT_PROTOCOL_ERROR); | |
1201 | packet_put_cstring(buf); | |
1202 | packet_put_cstring(""); | |
1203 | } else { | |
1204 | packet_start(SSH_MSG_DISCONNECT); | |
449c5ba5 | 1205 | packet_put_cstring(buf); |
7e7327a1 | 1206 | } |
5260325f | 1207 | packet_send(); |
1208 | packet_write_wait(); | |
1209 | ||
1210 | /* Stop listening for connections. */ | |
d6746a0b | 1211 | channel_close_all(); |
5260325f | 1212 | |
1213 | /* Close the connection. */ | |
1214 | packet_close(); | |
1215 | ||
1216 | /* Display the error locally and exit. */ | |
57112b5a | 1217 | log("Disconnecting: %.100s", buf); |
1218 | fatal_cleanup(); | |
8efc0c15 | 1219 | } |
1220 | ||
aa3378df | 1221 | /* Checks if there is any buffered output, and tries to write some of the output. */ |
8efc0c15 | 1222 | |
1223 | void | |
d5bb9418 | 1224 | packet_write_poll(void) |
8efc0c15 | 1225 | { |
5260325f | 1226 | int len = buffer_len(&output); |
1227 | if (len > 0) { | |
1228 | len = write(connection_out, buffer_ptr(&output), len); | |
1229 | if (len <= 0) { | |
1230 | if (errno == EAGAIN) | |
1231 | return; | |
1232 | else | |
1233 | fatal("Write failed: %.100s", strerror(errno)); | |
1234 | } | |
1235 | buffer_consume(&output, len); | |
1236 | } | |
8efc0c15 | 1237 | } |
1238 | ||
aa3378df | 1239 | /* |
1240 | * Calls packet_write_poll repeatedly until all pending output data has been | |
1241 | * written. | |
1242 | */ | |
8efc0c15 | 1243 | |
1244 | void | |
d5bb9418 | 1245 | packet_write_wait(void) |
8efc0c15 | 1246 | { |
20e04e90 | 1247 | fd_set *setp; |
1248 | ||
1249 | setp = (fd_set *)xmalloc(howmany(connection_out + 1, NFDBITS) * | |
1250 | sizeof(fd_mask)); | |
5260325f | 1251 | packet_write_poll(); |
1252 | while (packet_have_data_to_write()) { | |
20e04e90 | 1253 | memset(setp, 0, howmany(connection_out + 1, NFDBITS) * |
1254 | sizeof(fd_mask)); | |
1255 | FD_SET(connection_out, setp); | |
1256 | while (select(connection_out + 1, NULL, setp, NULL, NULL) == -1 && | |
fd193ca4 | 1257 | (errno == EAGAIN || errno == EINTR)) |
1258 | ; | |
5260325f | 1259 | packet_write_poll(); |
1260 | } | |
20e04e90 | 1261 | xfree(setp); |
8efc0c15 | 1262 | } |
1263 | ||
1264 | /* Returns true if there is buffered data to write to the connection. */ | |
1265 | ||
1266 | int | |
d5bb9418 | 1267 | packet_have_data_to_write(void) |
8efc0c15 | 1268 | { |
5260325f | 1269 | return buffer_len(&output) != 0; |
8efc0c15 | 1270 | } |
1271 | ||
1272 | /* Returns true if there is not too much data to write to the connection. */ | |
1273 | ||
1274 | int | |
d5bb9418 | 1275 | packet_not_very_much_data_to_write(void) |
8efc0c15 | 1276 | { |
5260325f | 1277 | if (interactive_mode) |
1278 | return buffer_len(&output) < 16384; | |
1279 | else | |
1280 | return buffer_len(&output) < 128 * 1024; | |
8efc0c15 | 1281 | } |
1282 | ||
1283 | /* Informs that the current session is interactive. Sets IP flags for that. */ | |
1284 | ||
1285 | void | |
b5c334cc | 1286 | packet_set_interactive(int interactive) |
8efc0c15 | 1287 | { |
b5c334cc | 1288 | static int called = 0; |
64e0e67e | 1289 | #if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN) |
b5c334cc | 1290 | int lowdelay = IPTOS_LOWDELAY; |
1291 | int throughput = IPTOS_THROUGHPUT; | |
64e0e67e | 1292 | #endif |
5260325f | 1293 | |
b5c334cc | 1294 | if (called) |
1295 | return; | |
1296 | called = 1; | |
1297 | ||
5260325f | 1298 | /* Record that we are in interactive mode. */ |
1299 | interactive_mode = interactive; | |
1300 | ||
48e671d5 | 1301 | /* Only set socket options if using a socket. */ |
1302 | if (!packet_connection_is_on_socket()) | |
5260325f | 1303 | return; |
48e671d5 | 1304 | /* |
f546c780 | 1305 | * IPTOS_LOWDELAY and IPTOS_THROUGHPUT are IPv4 only |
48e671d5 | 1306 | */ |
5260325f | 1307 | if (interactive) { |
aa3378df | 1308 | /* |
1309 | * Set IP options for an interactive connection. Use | |
1310 | * IPTOS_LOWDELAY and TCP_NODELAY. | |
1311 | */ | |
132dd316 | 1312 | #if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN) |
f546c780 | 1313 | if (packet_connection_is_ipv4()) { |
0e3c1f95 | 1314 | if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, |
db518d9b | 1315 | &lowdelay, sizeof(lowdelay)) < 0) |
0e3c1f95 | 1316 | error("setsockopt IPTOS_LOWDELAY: %.100s", |
f546c780 | 1317 | strerror(errno)); |
1318 | } | |
c04f75f1 | 1319 | #endif |
bcc0381e | 1320 | set_nodelay(connection_in); |
f546c780 | 1321 | } else if (packet_connection_is_ipv4()) { |
aa3378df | 1322 | /* |
1323 | * Set IP options for a non-interactive connection. Use | |
1324 | * IPTOS_THROUGHPUT. | |
1325 | */ | |
132dd316 | 1326 | #if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN) |
db518d9b | 1327 | if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, &throughput, |
48e671d5 | 1328 | sizeof(throughput)) < 0) |
5260325f | 1329 | error("setsockopt IPTOS_THROUGHPUT: %.100s", strerror(errno)); |
c04f75f1 | 1330 | #endif |
5260325f | 1331 | } |
8efc0c15 | 1332 | } |
1333 | ||
1334 | /* Returns true if the current connection is interactive. */ | |
1335 | ||
1336 | int | |
d5bb9418 | 1337 | packet_is_interactive(void) |
8efc0c15 | 1338 | { |
5260325f | 1339 | return interactive_mode; |
8efc0c15 | 1340 | } |
9d6b7add | 1341 | |
1342 | int | |
1343 | packet_set_maxsize(int s) | |
1344 | { | |
5260325f | 1345 | static int called = 0; |
1346 | if (called) { | |
7e7327a1 | 1347 | log("packet_set_maxsize: called twice: old %d new %d", |
1348 | max_packet_size, s); | |
5260325f | 1349 | return -1; |
1350 | } | |
1351 | if (s < 4 * 1024 || s > 1024 * 1024) { | |
1352 | log("packet_set_maxsize: bad size %d", s); | |
1353 | return -1; | |
1354 | } | |
b6350327 | 1355 | called = 1; |
76735fe3 | 1356 | debug("packet_set_maxsize: setting to %d", s); |
5260325f | 1357 | max_packet_size = s; |
1358 | return s; | |
9d6b7add | 1359 | } |
a6215e53 | 1360 | |
b4b701be | 1361 | /* roundup current message to pad bytes */ |
1362 | void | |
1363 | packet_add_padding(u_char pad) | |
1364 | { | |
1365 | extra_pad = pad; | |
1366 | } | |
1367 | ||
a6215e53 | 1368 | /* |
1369 | * 9.2. Ignored Data Message | |
cd332296 | 1370 | * |
a6215e53 | 1371 | * byte SSH_MSG_IGNORE |
1372 | * string data | |
cd332296 | 1373 | * |
a6215e53 | 1374 | * All implementations MUST understand (and ignore) this message at any |
1375 | * time (after receiving the protocol version). No implementation is | |
1376 | * required to send them. This message can be used as an additional | |
1377 | * protection measure against advanced traffic analysis techniques. | |
1378 | */ | |
95ce5599 | 1379 | void |
1380 | packet_send_ignore(int nbytes) | |
1381 | { | |
1382 | u_int32_t rand = 0; | |
1383 | int i; | |
1384 | ||
1385 | packet_start(compat20 ? SSH2_MSG_IGNORE : SSH_MSG_IGNORE); | |
a6215e53 | 1386 | packet_put_int(nbytes); |
184eed6a | 1387 | for (i = 0; i < nbytes; i++) { |
a6215e53 | 1388 | if (i % 4 == 0) |
1389 | rand = arc4random(); | |
1390 | packet_put_char(rand & 0xff); | |
1391 | rand >>= 8; | |
1392 | } | |
1393 | } |