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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" | |
bcc0381e | 40 | RCSID("$OpenBSD: packet.c,v 1.86 2002/01/24 21:09:25 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" | |
7e7327a1 | 62 | |
63 | #ifdef PACKET_DEBUG | |
64 | #define DBG(x) x | |
65 | #else | |
66 | #define DBG(x) | |
67 | #endif | |
68 | ||
aa3378df | 69 | /* |
70 | * This variable contains the file descriptors used for communicating with | |
71 | * the other side. connection_in is used for reading; connection_out for | |
72 | * writing. These can be the same descriptor, in which case it is assumed to | |
73 | * be a socket. | |
74 | */ | |
8efc0c15 | 75 | static int connection_in = -1; |
76 | static int connection_out = -1; | |
77 | ||
8efc0c15 | 78 | /* Protocol flags for the remote side. */ |
1e3b8b07 | 79 | static u_int remote_protocol_flags = 0; |
8efc0c15 | 80 | |
81 | /* Encryption context for receiving data. This is only used for decryption. */ | |
82 | static CipherContext receive_context; | |
5260325f | 83 | |
84 | /* Encryption context for sending data. This is only used for encryption. */ | |
8efc0c15 | 85 | static CipherContext send_context; |
86 | ||
87 | /* Buffer for raw input data from the socket. */ | |
88 | static Buffer input; | |
89 | ||
90 | /* Buffer for raw output data going to the socket. */ | |
91 | static Buffer output; | |
92 | ||
93 | /* Buffer for the partial outgoing packet being constructed. */ | |
94 | static Buffer outgoing_packet; | |
95 | ||
96 | /* Buffer for the incoming packet currently being processed. */ | |
97 | static Buffer incoming_packet; | |
98 | ||
99 | /* Scratch buffer for packet compression/decompression. */ | |
100 | static Buffer compression_buffer; | |
6ba22c93 | 101 | static int compression_buffer_ready = 0; |
8efc0c15 | 102 | |
103 | /* Flag indicating whether packet compression/decompression is enabled. */ | |
104 | static int packet_compression = 0; | |
105 | ||
9d6b7add | 106 | /* default maximum packet size */ |
107 | int max_packet_size = 32768; | |
108 | ||
8efc0c15 | 109 | /* Flag indicating whether this module has been initialized. */ |
110 | static int initialized = 0; | |
111 | ||
112 | /* Set to true if the connection is interactive. */ | |
113 | static int interactive_mode = 0; | |
114 | ||
7e7327a1 | 115 | /* Session key information for Encryption and MAC */ |
d1ac6175 | 116 | Newkeys *newkeys[MODE_MAX]; |
7e7327a1 | 117 | |
b4b701be | 118 | /* roundup current message to extra_pad bytes */ |
119 | static u_char extra_pad = 0; | |
120 | ||
aa3378df | 121 | /* |
122 | * Sets the descriptors used for communication. Disables encryption until | |
123 | * packet_set_encryption_key is called. | |
124 | */ | |
8efc0c15 | 125 | void |
126 | packet_set_connection(int fd_in, int fd_out) | |
127 | { | |
94ec8c6b | 128 | Cipher *none = cipher_by_name("none"); |
129 | if (none == NULL) | |
130 | fatal("packet_set_connection: cannot load cipher 'none'"); | |
5260325f | 131 | connection_in = fd_in; |
132 | connection_out = fd_out; | |
e6207598 | 133 | cipher_init(&send_context, none, "", 0, NULL, 0); |
134 | cipher_init(&receive_context, none, "", 0, NULL, 0); | |
08dcb5d7 | 135 | newkeys[MODE_IN] = newkeys[MODE_OUT] = NULL; |
5260325f | 136 | if (!initialized) { |
137 | initialized = 1; | |
138 | buffer_init(&input); | |
139 | buffer_init(&output); | |
140 | buffer_init(&outgoing_packet); | |
141 | buffer_init(&incoming_packet); | |
142 | } | |
143 | /* Kludge: arrange the close function to be called from fatal(). */ | |
144 | fatal_add_cleanup((void (*) (void *)) packet_close, NULL); | |
8efc0c15 | 145 | } |
146 | ||
48e671d5 | 147 | /* Returns 1 if remote host is connected via socket, 0 if not. */ |
148 | ||
149 | int | |
d5bb9418 | 150 | packet_connection_is_on_socket(void) |
48e671d5 | 151 | { |
152 | struct sockaddr_storage from, to; | |
153 | socklen_t fromlen, tolen; | |
154 | ||
155 | /* filedescriptors in and out are the same, so it's a socket */ | |
156 | if (connection_in == connection_out) | |
157 | return 1; | |
158 | fromlen = sizeof(from); | |
159 | memset(&from, 0, sizeof(from)); | |
9bc5ddfe | 160 | if (getpeername(connection_in, (struct sockaddr *)&from, &fromlen) < 0) |
48e671d5 | 161 | return 0; |
162 | tolen = sizeof(to); | |
163 | memset(&to, 0, sizeof(to)); | |
9bc5ddfe | 164 | if (getpeername(connection_out, (struct sockaddr *)&to, &tolen) < 0) |
48e671d5 | 165 | return 0; |
166 | if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0) | |
167 | return 0; | |
168 | if (from.ss_family != AF_INET && from.ss_family != AF_INET6) | |
169 | return 0; | |
170 | return 1; | |
171 | } | |
172 | ||
173 | /* returns 1 if connection is via ipv4 */ | |
174 | ||
175 | int | |
d5bb9418 | 176 | packet_connection_is_ipv4(void) |
48e671d5 | 177 | { |
178 | struct sockaddr_storage to; | |
d45317d8 | 179 | socklen_t tolen = sizeof(to); |
48e671d5 | 180 | |
181 | memset(&to, 0, sizeof(to)); | |
182 | if (getsockname(connection_out, (struct sockaddr *)&to, &tolen) < 0) | |
183 | return 0; | |
184 | if (to.ss_family != AF_INET) | |
185 | return 0; | |
186 | return 1; | |
187 | } | |
188 | ||
8efc0c15 | 189 | /* Sets the connection into non-blocking mode. */ |
190 | ||
191 | void | |
d5bb9418 | 192 | packet_set_nonblocking(void) |
8efc0c15 | 193 | { |
5260325f | 194 | /* Set the socket into non-blocking mode. */ |
195 | if (fcntl(connection_in, F_SETFL, O_NONBLOCK) < 0) | |
196 | error("fcntl O_NONBLOCK: %.100s", strerror(errno)); | |
8efc0c15 | 197 | |
5260325f | 198 | if (connection_out != connection_in) { |
199 | if (fcntl(connection_out, F_SETFL, O_NONBLOCK) < 0) | |
200 | error("fcntl O_NONBLOCK: %.100s", strerror(errno)); | |
201 | } | |
8efc0c15 | 202 | } |
203 | ||
204 | /* Returns the socket used for reading. */ | |
205 | ||
206 | int | |
d5bb9418 | 207 | packet_get_connection_in(void) |
8efc0c15 | 208 | { |
5260325f | 209 | return connection_in; |
8efc0c15 | 210 | } |
211 | ||
212 | /* Returns the descriptor used for writing. */ | |
213 | ||
214 | int | |
d5bb9418 | 215 | packet_get_connection_out(void) |
8efc0c15 | 216 | { |
5260325f | 217 | return connection_out; |
8efc0c15 | 218 | } |
219 | ||
220 | /* Closes the connection and clears and frees internal data structures. */ | |
221 | ||
222 | void | |
d5bb9418 | 223 | packet_close(void) |
8efc0c15 | 224 | { |
5260325f | 225 | if (!initialized) |
226 | return; | |
227 | initialized = 0; | |
228 | if (connection_in == connection_out) { | |
229 | shutdown(connection_out, SHUT_RDWR); | |
230 | close(connection_out); | |
231 | } else { | |
232 | close(connection_in); | |
233 | close(connection_out); | |
234 | } | |
235 | buffer_free(&input); | |
236 | buffer_free(&output); | |
237 | buffer_free(&outgoing_packet); | |
238 | buffer_free(&incoming_packet); | |
6ba22c93 | 239 | if (compression_buffer_ready) { |
5260325f | 240 | buffer_free(&compression_buffer); |
241 | buffer_compress_uninit(); | |
242 | } | |
8efc0c15 | 243 | } |
244 | ||
245 | /* Sets remote side protocol flags. */ | |
246 | ||
247 | void | |
1e3b8b07 | 248 | packet_set_protocol_flags(u_int protocol_flags) |
8efc0c15 | 249 | { |
5260325f | 250 | remote_protocol_flags = protocol_flags; |
8efc0c15 | 251 | } |
252 | ||
253 | /* Returns the remote protocol flags set earlier by the above function. */ | |
254 | ||
1e3b8b07 | 255 | u_int |
d5bb9418 | 256 | packet_get_protocol_flags(void) |
8efc0c15 | 257 | { |
5260325f | 258 | return remote_protocol_flags; |
8efc0c15 | 259 | } |
260 | ||
aa3378df | 261 | /* |
262 | * Starts packet compression from the next packet on in both directions. | |
263 | * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip. | |
264 | */ | |
8efc0c15 | 265 | |
396c147e | 266 | static void |
267 | packet_init_compression(void) | |
6ba22c93 | 268 | { |
269 | if (compression_buffer_ready == 1) | |
270 | return; | |
271 | compression_buffer_ready = 1; | |
272 | buffer_init(&compression_buffer); | |
273 | } | |
274 | ||
8efc0c15 | 275 | void |
276 | packet_start_compression(int level) | |
277 | { | |
08dcb5d7 | 278 | if (packet_compression && !compat20) |
5260325f | 279 | fatal("Compression already enabled."); |
280 | packet_compression = 1; | |
6ba22c93 | 281 | packet_init_compression(); |
282 | buffer_compress_init_send(level); | |
283 | buffer_compress_init_recv(); | |
8efc0c15 | 284 | } |
285 | ||
aa3378df | 286 | /* |
287 | * Causes any further packets to be encrypted using the given key. The same | |
288 | * key is used for both sending and reception. However, both directions are | |
289 | * encrypted independently of each other. | |
290 | */ | |
8efc0c15 | 291 | void |
1e3b8b07 | 292 | packet_set_encryption_key(const u_char *key, u_int keylen, |
94ec8c6b | 293 | int number) |
8efc0c15 | 294 | { |
94ec8c6b | 295 | Cipher *cipher = cipher_by_number(number); |
296 | if (cipher == NULL) | |
297 | fatal("packet_set_encryption_key: unknown cipher number %d", number); | |
7e7327a1 | 298 | if (keylen < 20) |
94ec8c6b | 299 | fatal("packet_set_encryption_key: keylen too small: %d", keylen); |
300 | cipher_init(&receive_context, cipher, key, keylen, NULL, 0); | |
301 | cipher_init(&send_context, cipher, key, keylen, NULL, 0); | |
8efc0c15 | 302 | } |
303 | ||
08dcb5d7 | 304 | /* Start constructing a packet to send. */ |
8efc0c15 | 305 | void |
08dcb5d7 | 306 | packet_start(u_char type) |
8efc0c15 | 307 | { |
08dcb5d7 | 308 | u_char buf[9]; |
309 | int len; | |
7e7327a1 | 310 | |
12bf85ed | 311 | DBG(debug("packet_start[%d]", type)); |
08dcb5d7 | 312 | len = compat20 ? 6 : 9; |
313 | memset(buf, 0, len - 1); | |
314 | buf[len - 1] = type; | |
315 | buffer_clear(&outgoing_packet); | |
316 | buffer_append(&outgoing_packet, buf, len); | |
7e7327a1 | 317 | } |
318 | ||
08dcb5d7 | 319 | /* Append payload. */ |
8efc0c15 | 320 | void |
321 | packet_put_char(int value) | |
322 | { | |
5260325f | 323 | char ch = value; |
324 | buffer_append(&outgoing_packet, &ch, 1); | |
8efc0c15 | 325 | } |
8efc0c15 | 326 | void |
1e3b8b07 | 327 | packet_put_int(u_int value) |
8efc0c15 | 328 | { |
5260325f | 329 | buffer_put_int(&outgoing_packet, value); |
8efc0c15 | 330 | } |
8efc0c15 | 331 | void |
6c0fa2b1 | 332 | packet_put_string(const void *buf, u_int len) |
8efc0c15 | 333 | { |
5260325f | 334 | buffer_put_string(&outgoing_packet, buf, len); |
8efc0c15 | 335 | } |
7e7327a1 | 336 | void |
337 | packet_put_cstring(const char *str) | |
338 | { | |
449c5ba5 | 339 | buffer_put_cstring(&outgoing_packet, str); |
7e7327a1 | 340 | } |
7e7327a1 | 341 | void |
6c0fa2b1 | 342 | packet_put_raw(const void *buf, u_int len) |
7e7327a1 | 343 | { |
344 | buffer_append(&outgoing_packet, buf, len); | |
345 | } | |
8efc0c15 | 346 | void |
5260325f | 347 | packet_put_bignum(BIGNUM * value) |
8efc0c15 | 348 | { |
5260325f | 349 | buffer_put_bignum(&outgoing_packet, value); |
8efc0c15 | 350 | } |
7e7327a1 | 351 | void |
352 | packet_put_bignum2(BIGNUM * value) | |
353 | { | |
354 | buffer_put_bignum2(&outgoing_packet, value); | |
355 | } | |
8efc0c15 | 356 | |
aa3378df | 357 | /* |
358 | * Finalizes and sends the packet. If the encryption key has been set, | |
359 | * encrypts the packet before sending. | |
360 | */ | |
5260325f | 361 | |
396c147e | 362 | static void |
5ca51e19 | 363 | packet_send1(void) |
8efc0c15 | 364 | { |
5260325f | 365 | char buf[8], *cp; |
366 | int i, padding, len; | |
1e3b8b07 | 367 | u_int checksum; |
5260325f | 368 | u_int32_t rand = 0; |
369 | ||
aa3378df | 370 | /* |
371 | * If using packet compression, compress the payload of the outgoing | |
372 | * packet. | |
373 | */ | |
5260325f | 374 | if (packet_compression) { |
375 | buffer_clear(&compression_buffer); | |
376 | /* Skip padding. */ | |
377 | buffer_consume(&outgoing_packet, 8); | |
378 | /* padding */ | |
379 | buffer_append(&compression_buffer, "\0\0\0\0\0\0\0\0", 8); | |
380 | buffer_compress(&outgoing_packet, &compression_buffer); | |
381 | buffer_clear(&outgoing_packet); | |
382 | buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer), | |
184eed6a | 383 | buffer_len(&compression_buffer)); |
5260325f | 384 | } |
385 | /* Compute packet length without padding (add checksum, remove padding). */ | |
386 | len = buffer_len(&outgoing_packet) + 4 - 8; | |
387 | ||
1d1ffb87 | 388 | /* Insert padding. Initialized to zero in packet_start1() */ |
5260325f | 389 | padding = 8 - len % 8; |
08dcb5d7 | 390 | if (send_context.cipher->number != SSH_CIPHER_NONE) { |
5260325f | 391 | cp = buffer_ptr(&outgoing_packet); |
392 | for (i = 0; i < padding; i++) { | |
393 | if (i % 4 == 0) | |
394 | rand = arc4random(); | |
395 | cp[7 - i] = rand & 0xff; | |
396 | rand >>= 8; | |
397 | } | |
398 | } | |
399 | buffer_consume(&outgoing_packet, 8 - padding); | |
400 | ||
401 | /* Add check bytes. */ | |
20905a8e | 402 | checksum = ssh_crc32(buffer_ptr(&outgoing_packet), |
2e73a022 | 403 | buffer_len(&outgoing_packet)); |
5260325f | 404 | PUT_32BIT(buf, checksum); |
405 | buffer_append(&outgoing_packet, buf, 4); | |
8efc0c15 | 406 | |
407 | #ifdef PACKET_DEBUG | |
5260325f | 408 | fprintf(stderr, "packet_send plain: "); |
409 | buffer_dump(&outgoing_packet); | |
8efc0c15 | 410 | #endif |
411 | ||
5260325f | 412 | /* Append to output. */ |
413 | PUT_32BIT(buf, len); | |
414 | buffer_append(&output, buf, 4); | |
6c0fa2b1 | 415 | cp = buffer_append_space(&output, buffer_len(&outgoing_packet)); |
08dcb5d7 | 416 | cipher_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet), |
184eed6a | 417 | buffer_len(&outgoing_packet)); |
5260325f | 418 | |
8efc0c15 | 419 | #ifdef PACKET_DEBUG |
5260325f | 420 | fprintf(stderr, "encrypted: "); |
421 | buffer_dump(&output); | |
8efc0c15 | 422 | #endif |
423 | ||
5260325f | 424 | buffer_clear(&outgoing_packet); |
8efc0c15 | 425 | |
aa3378df | 426 | /* |
427 | * Note that the packet is now only buffered in output. It won\'t be | |
428 | * actually sent until packet_write_wait or packet_write_poll is | |
429 | * called. | |
430 | */ | |
8efc0c15 | 431 | } |
432 | ||
396c147e | 433 | static void |
d1ac6175 | 434 | set_newkeys(int mode) |
435 | { | |
436 | Enc *enc; | |
437 | Mac *mac; | |
438 | Comp *comp; | |
439 | CipherContext *cc; | |
440 | ||
441 | debug("newkeys: mode %d", mode); | |
442 | ||
443 | cc = (mode == MODE_OUT) ? &send_context : &receive_context; | |
444 | if (newkeys[mode] != NULL) { | |
445 | debug("newkeys: rekeying"); | |
d8ee838b | 446 | /* todo: free old keys, reset compression/cipher-ctxt; */ |
a7ca6275 | 447 | memset(cc, 0, sizeof(*cc)); |
448 | enc = &newkeys[mode]->enc; | |
449 | mac = &newkeys[mode]->mac; | |
450 | comp = &newkeys[mode]->comp; | |
cd332296 | 451 | memset(mac->key, 0, mac->key_len); |
a7ca6275 | 452 | xfree(enc->name); |
453 | xfree(enc->iv); | |
454 | xfree(enc->key); | |
455 | xfree(mac->name); | |
456 | xfree(mac->key); | |
457 | xfree(comp->name); | |
d8ee838b | 458 | xfree(newkeys[mode]); |
d1ac6175 | 459 | } |
460 | newkeys[mode] = kex_get_newkeys(mode); | |
461 | if (newkeys[mode] == NULL) | |
462 | fatal("newkeys: no keys for mode %d", mode); | |
463 | enc = &newkeys[mode]->enc; | |
464 | mac = &newkeys[mode]->mac; | |
465 | comp = &newkeys[mode]->comp; | |
466 | if (mac->md != NULL) | |
467 | mac->enabled = 1; | |
468 | DBG(debug("cipher_init_context: %d", mode)); | |
469 | cipher_init(cc, enc->cipher, enc->key, enc->cipher->key_len, | |
470 | enc->iv, enc->cipher->block_size); | |
a7ca6275 | 471 | memset(enc->iv, 0, enc->cipher->block_size); |
472 | memset(enc->key, 0, enc->cipher->key_len); | |
d1ac6175 | 473 | if (comp->type != 0 && comp->enabled == 0) { |
6ba22c93 | 474 | packet_init_compression(); |
475 | if (mode == MODE_OUT) | |
476 | buffer_compress_init_send(6); | |
477 | else | |
478 | buffer_compress_init_recv(); | |
d1ac6175 | 479 | comp->enabled = 1; |
d1ac6175 | 480 | } |
481 | } | |
482 | ||
7e7327a1 | 483 | /* |
484 | * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue) | |
485 | */ | |
396c147e | 486 | static void |
5ca51e19 | 487 | packet_send2(void) |
7e7327a1 | 488 | { |
b2552997 | 489 | static u_int32_t seqnr = 0; |
08dcb5d7 | 490 | u_char type, *ucp, *macbuf = NULL; |
b4b701be | 491 | u_char padlen, pad; |
7e7327a1 | 492 | char *cp; |
1e3b8b07 | 493 | u_int packet_length = 0; |
b4b701be | 494 | u_int i, len; |
7e7327a1 | 495 | u_int32_t rand = 0; |
7e7327a1 | 496 | Enc *enc = NULL; |
497 | Mac *mac = NULL; | |
498 | Comp *comp = NULL; | |
499 | int block_size; | |
500 | ||
d1ac6175 | 501 | if (newkeys[MODE_OUT] != NULL) { |
502 | enc = &newkeys[MODE_OUT]->enc; | |
503 | mac = &newkeys[MODE_OUT]->mac; | |
504 | comp = &newkeys[MODE_OUT]->comp; | |
7e7327a1 | 505 | } |
94ec8c6b | 506 | block_size = enc ? enc->cipher->block_size : 8; |
7e7327a1 | 507 | |
20905a8e | 508 | ucp = buffer_ptr(&outgoing_packet); |
08dcb5d7 | 509 | type = ucp[5]; |
7e7327a1 | 510 | |
511 | #ifdef PACKET_DEBUG | |
512 | fprintf(stderr, "plain: "); | |
513 | buffer_dump(&outgoing_packet); | |
514 | #endif | |
515 | ||
516 | if (comp && comp->enabled) { | |
517 | len = buffer_len(&outgoing_packet); | |
518 | /* skip header, compress only payload */ | |
519 | buffer_consume(&outgoing_packet, 5); | |
520 | buffer_clear(&compression_buffer); | |
521 | buffer_compress(&outgoing_packet, &compression_buffer); | |
522 | buffer_clear(&outgoing_packet); | |
523 | buffer_append(&outgoing_packet, "\0\0\0\0\0", 5); | |
524 | buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer), | |
525 | buffer_len(&compression_buffer)); | |
526 | DBG(debug("compression: raw %d compressed %d", len, | |
527 | buffer_len(&outgoing_packet))); | |
528 | } | |
529 | ||
530 | /* sizeof (packet_len + pad_len + payload) */ | |
531 | len = buffer_len(&outgoing_packet); | |
532 | ||
533 | /* | |
534 | * calc size of padding, alloc space, get random data, | |
535 | * minimum padding is 4 bytes | |
536 | */ | |
537 | padlen = block_size - (len % block_size); | |
538 | if (padlen < 4) | |
539 | padlen += block_size; | |
b4b701be | 540 | if (extra_pad) { |
541 | /* will wrap if extra_pad+padlen > 255 */ | |
542 | extra_pad = roundup(extra_pad, block_size); | |
543 | pad = extra_pad - ((len + padlen) % extra_pad); | |
544 | debug("packet_send2: adding %d (len %d padlen %d extra_pad %d)", | |
545 | pad, len, padlen, extra_pad); | |
546 | padlen += pad; | |
547 | extra_pad = 0; | |
548 | } | |
6c0fa2b1 | 549 | cp = buffer_append_space(&outgoing_packet, padlen); |
94ec8c6b | 550 | if (enc && enc->cipher->number != SSH_CIPHER_NONE) { |
1d1ffb87 | 551 | /* random padding */ |
7e7327a1 | 552 | for (i = 0; i < padlen; i++) { |
553 | if (i % 4 == 0) | |
554 | rand = arc4random(); | |
555 | cp[i] = rand & 0xff; | |
6e18cb71 | 556 | rand >>= 8; |
7e7327a1 | 557 | } |
1d1ffb87 | 558 | } else { |
559 | /* clear padding */ | |
560 | memset(cp, 0, padlen); | |
7e7327a1 | 561 | } |
562 | /* packet_length includes payload, padding and padding length field */ | |
563 | packet_length = buffer_len(&outgoing_packet) - 4; | |
20905a8e | 564 | ucp = buffer_ptr(&outgoing_packet); |
08dcb5d7 | 565 | PUT_32BIT(ucp, packet_length); |
566 | ucp[4] = padlen; | |
7e7327a1 | 567 | DBG(debug("send: len %d (includes padlen %d)", packet_length+4, padlen)); |
568 | ||
569 | /* compute MAC over seqnr and packet(length fields, payload, padding) */ | |
570 | if (mac && mac->enabled) { | |
b2552997 | 571 | macbuf = mac_compute(mac, seqnr, |
20905a8e | 572 | buffer_ptr(&outgoing_packet), |
b2552997 | 573 | buffer_len(&outgoing_packet)); |
94ec8c6b | 574 | DBG(debug("done calc MAC out #%d", seqnr)); |
7e7327a1 | 575 | } |
576 | /* encrypt packet and append to output buffer. */ | |
6c0fa2b1 | 577 | cp = buffer_append_space(&output, buffer_len(&outgoing_packet)); |
08dcb5d7 | 578 | cipher_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet), |
7e7327a1 | 579 | buffer_len(&outgoing_packet)); |
580 | /* append unencrypted MAC */ | |
581 | if (mac && mac->enabled) | |
582 | buffer_append(&output, (char *)macbuf, mac->mac_len); | |
583 | #ifdef PACKET_DEBUG | |
584 | fprintf(stderr, "encrypted: "); | |
585 | buffer_dump(&output); | |
586 | #endif | |
6ae2364d | 587 | /* increment sequence number for outgoing packets */ |
588 | if (++seqnr == 0) | |
589 | log("outgoing seqnr wraps around"); | |
7e7327a1 | 590 | buffer_clear(&outgoing_packet); |
591 | ||
d1ac6175 | 592 | if (type == SSH2_MSG_NEWKEYS) |
593 | set_newkeys(MODE_OUT); | |
7e7327a1 | 594 | } |
595 | ||
596 | void | |
d5bb9418 | 597 | packet_send(void) |
7e7327a1 | 598 | { |
08dcb5d7 | 599 | if (compat20) |
7e7327a1 | 600 | packet_send2(); |
601 | else | |
602 | packet_send1(); | |
603 | DBG(debug("packet_send done")); | |
604 | } | |
605 | ||
aa3378df | 606 | /* |
607 | * Waits until a packet has been received, and returns its type. Note that | |
608 | * no other data is processed until this returns, so this function should not | |
609 | * be used during the interactive session. | |
610 | */ | |
8efc0c15 | 611 | |
612 | int | |
54a5250f | 613 | packet_read_seqnr(u_int32_t *seqnr_p) |
8efc0c15 | 614 | { |
5260325f | 615 | int type, len; |
20e04e90 | 616 | fd_set *setp; |
5260325f | 617 | char buf[8192]; |
7e7327a1 | 618 | DBG(debug("packet_read()")); |
5260325f | 619 | |
20e04e90 | 620 | setp = (fd_set *)xmalloc(howmany(connection_in+1, NFDBITS) * |
621 | sizeof(fd_mask)); | |
622 | ||
5260325f | 623 | /* Since we are blocking, ensure that all written packets have been sent. */ |
624 | packet_write_wait(); | |
625 | ||
626 | /* Stay in the loop until we have received a complete packet. */ | |
627 | for (;;) { | |
628 | /* Try to read a packet from the buffer. */ | |
54a5250f | 629 | type = packet_read_poll_seqnr(seqnr_p); |
08dcb5d7 | 630 | if (!compat20 && ( |
1d1ffb87 | 631 | type == SSH_SMSG_SUCCESS |
5260325f | 632 | || type == SSH_SMSG_FAILURE |
633 | || type == SSH_CMSG_EOF | |
1d1ffb87 | 634 | || type == SSH_CMSG_EXIT_CONFIRMATION)) |
95500969 | 635 | packet_check_eom(); |
5260325f | 636 | /* If we got a packet, return it. */ |
20e04e90 | 637 | if (type != SSH_MSG_NONE) { |
638 | xfree(setp); | |
5260325f | 639 | return type; |
20e04e90 | 640 | } |
aa3378df | 641 | /* |
642 | * Otherwise, wait for some data to arrive, add it to the | |
643 | * buffer, and try again. | |
644 | */ | |
20e04e90 | 645 | memset(setp, 0, howmany(connection_in + 1, NFDBITS) * |
646 | sizeof(fd_mask)); | |
647 | FD_SET(connection_in, setp); | |
aa3378df | 648 | |
5260325f | 649 | /* Wait for some data to arrive. */ |
20e04e90 | 650 | while (select(connection_in + 1, setp, NULL, NULL, NULL) == -1 && |
fd193ca4 | 651 | (errno == EAGAIN || errno == EINTR)) |
652 | ; | |
aa3378df | 653 | |
5260325f | 654 | /* Read data from the socket. */ |
655 | len = read(connection_in, buf, sizeof(buf)); | |
89cafde6 | 656 | if (len == 0) { |
657 | log("Connection closed by %.200s", get_remote_ipaddr()); | |
658 | fatal_cleanup(); | |
659 | } | |
5260325f | 660 | if (len < 0) |
661 | fatal("Read from socket failed: %.100s", strerror(errno)); | |
662 | /* Append it to the buffer. */ | |
663 | packet_process_incoming(buf, len); | |
664 | } | |
665 | /* NOTREACHED */ | |
8efc0c15 | 666 | } |
667 | ||
24ca6821 | 668 | int |
54a5250f | 669 | packet_read(void) |
24ca6821 | 670 | { |
54a5250f | 671 | return packet_read_seqnr(NULL); |
24ca6821 | 672 | } |
673 | ||
aa3378df | 674 | /* |
675 | * Waits until a packet has been received, verifies that its type matches | |
676 | * that given, and gives a fatal error and exits if there is a mismatch. | |
677 | */ | |
8efc0c15 | 678 | |
679 | void | |
54a5250f | 680 | packet_read_expect(int expected_type) |
8efc0c15 | 681 | { |
5260325f | 682 | int type; |
8efc0c15 | 683 | |
54a5250f | 684 | type = packet_read(); |
5260325f | 685 | if (type != expected_type) |
686 | packet_disconnect("Protocol error: expected packet type %d, got %d", | |
7e7327a1 | 687 | expected_type, type); |
8efc0c15 | 688 | } |
689 | ||
690 | /* Checks if a full packet is available in the data received so far via | |
5260325f | 691 | * packet_process_incoming. If so, reads the packet; otherwise returns |
692 | * SSH_MSG_NONE. This does not wait for data from the connection. | |
693 | * | |
694 | * SSH_MSG_DISCONNECT is handled specially here. Also, | |
695 | * SSH_MSG_IGNORE messages are skipped by this function and are never returned | |
696 | * to higher levels. | |
5260325f | 697 | */ |
8efc0c15 | 698 | |
396c147e | 699 | static int |
54a5250f | 700 | packet_read_poll1(void) |
8efc0c15 | 701 | { |
1e3b8b07 | 702 | u_int len, padded_len; |
08dcb5d7 | 703 | u_char *ucp, type; |
704 | char *cp; | |
1e3b8b07 | 705 | u_int checksum, stored_checksum; |
5260325f | 706 | |
5260325f | 707 | /* Check if input size is less than minimum packet size. */ |
708 | if (buffer_len(&input) < 4 + 8) | |
709 | return SSH_MSG_NONE; | |
710 | /* Get length of incoming packet. */ | |
20905a8e | 711 | ucp = buffer_ptr(&input); |
5260325f | 712 | len = GET_32BIT(ucp); |
713 | if (len < 1 + 2 + 2 || len > 256 * 1024) | |
714 | packet_disconnect("Bad packet length %d.", len); | |
715 | padded_len = (len + 8) & ~7; | |
716 | ||
717 | /* Check if the packet has been entirely received. */ | |
718 | if (buffer_len(&input) < 4 + padded_len) | |
719 | return SSH_MSG_NONE; | |
720 | ||
721 | /* The entire packet is in buffer. */ | |
722 | ||
723 | /* Consume packet length. */ | |
724 | buffer_consume(&input, 4); | |
725 | ||
08dcb5d7 | 726 | /* |
727 | * Cryptographic attack detector for ssh | |
728 | * (C)1998 CORE-SDI, Buenos Aires Argentina | |
729 | * Ariel Futoransky(futo@core-sdi.com) | |
730 | */ | |
731 | if (receive_context.cipher->number != SSH_CIPHER_NONE && | |
732 | detect_attack(buffer_ptr(&input), padded_len, NULL) == DEATTACK_DETECTED) | |
733 | packet_disconnect("crc32 compensation attack: network attack detected"); | |
734 | ||
735 | /* Decrypt data to incoming_packet. */ | |
5260325f | 736 | buffer_clear(&incoming_packet); |
6c0fa2b1 | 737 | cp = buffer_append_space(&incoming_packet, padded_len); |
08dcb5d7 | 738 | cipher_decrypt(&receive_context, cp, buffer_ptr(&input), padded_len); |
739 | ||
5260325f | 740 | buffer_consume(&input, padded_len); |
8efc0c15 | 741 | |
742 | #ifdef PACKET_DEBUG | |
5260325f | 743 | fprintf(stderr, "read_poll plain: "); |
744 | buffer_dump(&incoming_packet); | |
8efc0c15 | 745 | #endif |
5260325f | 746 | |
747 | /* Compute packet checksum. */ | |
20905a8e | 748 | checksum = ssh_crc32(buffer_ptr(&incoming_packet), |
7e7327a1 | 749 | buffer_len(&incoming_packet) - 4); |
5260325f | 750 | |
751 | /* Skip padding. */ | |
752 | buffer_consume(&incoming_packet, 8 - len % 8); | |
753 | ||
754 | /* Test check bytes. */ | |
5260325f | 755 | if (len != buffer_len(&incoming_packet)) |
24ca6821 | 756 | packet_disconnect("packet_read_poll1: len %d != buffer_len %d.", |
7e7327a1 | 757 | len, buffer_len(&incoming_packet)); |
5260325f | 758 | |
20905a8e | 759 | ucp = (u_char *)buffer_ptr(&incoming_packet) + len - 4; |
5260325f | 760 | stored_checksum = GET_32BIT(ucp); |
761 | if (checksum != stored_checksum) | |
762 | packet_disconnect("Corrupted check bytes on input."); | |
763 | buffer_consume_end(&incoming_packet, 4); | |
764 | ||
5260325f | 765 | if (packet_compression) { |
766 | buffer_clear(&compression_buffer); | |
767 | buffer_uncompress(&incoming_packet, &compression_buffer); | |
768 | buffer_clear(&incoming_packet); | |
769 | buffer_append(&incoming_packet, buffer_ptr(&compression_buffer), | |
7e7327a1 | 770 | buffer_len(&compression_buffer)); |
5260325f | 771 | } |
08dcb5d7 | 772 | type = buffer_get_char(&incoming_packet); |
08dcb5d7 | 773 | return type; |
5260325f | 774 | } |
775 | ||
396c147e | 776 | static int |
54a5250f | 777 | packet_read_poll2(u_int32_t *seqnr_p) |
7e7327a1 | 778 | { |
b2552997 | 779 | static u_int32_t seqnr = 0; |
780 | static u_int packet_length = 0; | |
1e3b8b07 | 781 | u_int padlen, need; |
08dcb5d7 | 782 | u_char *macbuf, *ucp, type; |
7e7327a1 | 783 | char *cp; |
7e7327a1 | 784 | int maclen, block_size; |
785 | Enc *enc = NULL; | |
786 | Mac *mac = NULL; | |
787 | Comp *comp = NULL; | |
788 | ||
d1ac6175 | 789 | if (newkeys[MODE_IN] != NULL) { |
790 | enc = &newkeys[MODE_IN]->enc; | |
791 | mac = &newkeys[MODE_IN]->mac; | |
792 | comp = &newkeys[MODE_IN]->comp; | |
7e7327a1 | 793 | } |
794 | maclen = mac && mac->enabled ? mac->mac_len : 0; | |
94ec8c6b | 795 | block_size = enc ? enc->cipher->block_size : 8; |
7e7327a1 | 796 | |
797 | if (packet_length == 0) { | |
798 | /* | |
799 | * check if input size is less than the cipher block size, | |
800 | * decrypt first block and extract length of incoming packet | |
801 | */ | |
802 | if (buffer_len(&input) < block_size) | |
803 | return SSH_MSG_NONE; | |
804 | buffer_clear(&incoming_packet); | |
6c0fa2b1 | 805 | cp = buffer_append_space(&incoming_packet, block_size); |
08dcb5d7 | 806 | cipher_decrypt(&receive_context, cp, buffer_ptr(&input), |
7e7327a1 | 807 | block_size); |
20905a8e | 808 | ucp = buffer_ptr(&incoming_packet); |
7e7327a1 | 809 | packet_length = GET_32BIT(ucp); |
810 | if (packet_length < 1 + 4 || packet_length > 256 * 1024) { | |
811 | buffer_dump(&incoming_packet); | |
812 | packet_disconnect("Bad packet length %d.", packet_length); | |
813 | } | |
814 | DBG(debug("input: packet len %d", packet_length+4)); | |
815 | buffer_consume(&input, block_size); | |
816 | } | |
817 | /* we have a partial packet of block_size bytes */ | |
818 | need = 4 + packet_length - block_size; | |
819 | DBG(debug("partial packet %d, need %d, maclen %d", block_size, | |
820 | need, maclen)); | |
821 | if (need % block_size != 0) | |
822 | fatal("padding error: need %d block %d mod %d", | |
823 | need, block_size, need % block_size); | |
824 | /* | |
825 | * check if the entire packet has been received and | |
826 | * decrypt into incoming_packet | |
827 | */ | |
828 | if (buffer_len(&input) < need + maclen) | |
829 | return SSH_MSG_NONE; | |
830 | #ifdef PACKET_DEBUG | |
831 | fprintf(stderr, "read_poll enc/full: "); | |
832 | buffer_dump(&input); | |
833 | #endif | |
6c0fa2b1 | 834 | cp = buffer_append_space(&incoming_packet, need); |
08dcb5d7 | 835 | cipher_decrypt(&receive_context, cp, buffer_ptr(&input), need); |
7e7327a1 | 836 | buffer_consume(&input, need); |
837 | /* | |
838 | * compute MAC over seqnr and packet, | |
839 | * increment sequence number for incoming packet | |
840 | */ | |
6ae2364d | 841 | if (mac && mac->enabled) { |
b2552997 | 842 | macbuf = mac_compute(mac, seqnr, |
20905a8e | 843 | buffer_ptr(&incoming_packet), |
b2552997 | 844 | buffer_len(&incoming_packet)); |
7e7327a1 | 845 | if (memcmp(macbuf, buffer_ptr(&input), mac->mac_len) != 0) |
94ec8c6b | 846 | packet_disconnect("Corrupted MAC on input."); |
847 | DBG(debug("MAC #%d ok", seqnr)); | |
7e7327a1 | 848 | buffer_consume(&input, mac->mac_len); |
849 | } | |
24ca6821 | 850 | if (seqnr_p != NULL) |
851 | *seqnr_p = seqnr; | |
6ae2364d | 852 | if (++seqnr == 0) |
853 | log("incoming seqnr wraps around"); | |
7e7327a1 | 854 | |
855 | /* get padlen */ | |
6c0fa2b1 | 856 | cp = buffer_ptr(&incoming_packet); |
857 | cp += 4; | |
08dcb5d7 | 858 | padlen = (u_char) *cp; |
7e7327a1 | 859 | DBG(debug("input: padlen %d", padlen)); |
860 | if (padlen < 4) | |
861 | packet_disconnect("Corrupted padlen %d on input.", padlen); | |
862 | ||
863 | /* skip packet size + padlen, discard padding */ | |
864 | buffer_consume(&incoming_packet, 4 + 1); | |
865 | buffer_consume_end(&incoming_packet, padlen); | |
866 | ||
867 | DBG(debug("input: len before de-compress %d", buffer_len(&incoming_packet))); | |
868 | if (comp && comp->enabled) { | |
869 | buffer_clear(&compression_buffer); | |
870 | buffer_uncompress(&incoming_packet, &compression_buffer); | |
871 | buffer_clear(&incoming_packet); | |
872 | buffer_append(&incoming_packet, buffer_ptr(&compression_buffer), | |
873 | buffer_len(&compression_buffer)); | |
874 | DBG(debug("input: len after de-compress %d", buffer_len(&incoming_packet))); | |
875 | } | |
876 | /* | |
877 | * get packet type, implies consume. | |
878 | * return length of payload (without type field) | |
879 | */ | |
08dcb5d7 | 880 | type = buffer_get_char(&incoming_packet); |
d1ac6175 | 881 | if (type == SSH2_MSG_NEWKEYS) |
882 | set_newkeys(MODE_IN); | |
7e7327a1 | 883 | #ifdef PACKET_DEBUG |
12bf85ed | 884 | fprintf(stderr, "read/plain[%d]:\r\n", type); |
7e7327a1 | 885 | buffer_dump(&incoming_packet); |
886 | #endif | |
08dcb5d7 | 887 | /* reset for next packet */ |
888 | packet_length = 0; | |
889 | return type; | |
7e7327a1 | 890 | } |
891 | ||
892 | int | |
54a5250f | 893 | packet_read_poll_seqnr(u_int32_t *seqnr_p) |
7e7327a1 | 894 | { |
5a5f4c37 | 895 | int reason, seqnr; |
08dcb5d7 | 896 | u_char type; |
7e7327a1 | 897 | char *msg; |
7e7327a1 | 898 | |
08dcb5d7 | 899 | for (;;) { |
900 | if (compat20) { | |
54a5250f | 901 | type = packet_read_poll2(seqnr_p); |
08dcb5d7 | 902 | if (type) |
7e7327a1 | 903 | DBG(debug("received packet type %d", type)); |
6aacefa7 | 904 | switch (type) { |
7e7327a1 | 905 | case SSH2_MSG_IGNORE: |
906 | break; | |
907 | case SSH2_MSG_DEBUG: | |
908 | packet_get_char(); | |
909 | msg = packet_get_string(NULL); | |
910 | debug("Remote: %.900s", msg); | |
911 | xfree(msg); | |
912 | msg = packet_get_string(NULL); | |
913 | xfree(msg); | |
914 | break; | |
915 | case SSH2_MSG_DISCONNECT: | |
916 | reason = packet_get_int(); | |
917 | msg = packet_get_string(NULL); | |
7c49df64 | 918 | log("Received disconnect from %s: %d: %.400s", get_remote_ipaddr(), |
919 | reason, msg); | |
7e7327a1 | 920 | xfree(msg); |
921 | fatal_cleanup(); | |
922 | break; | |
5a5f4c37 | 923 | case SSH2_MSG_UNIMPLEMENTED: |
924 | seqnr = packet_get_int(); | |
925 | debug("Received SSH2_MSG_UNIMPLEMENTED for %d", seqnr); | |
926 | break; | |
7e7327a1 | 927 | default: |
928 | return type; | |
929 | break; | |
2b87da3b | 930 | } |
7e7327a1 | 931 | } else { |
54a5250f | 932 | type = packet_read_poll1(); |
6aacefa7 | 933 | switch (type) { |
7e7327a1 | 934 | case SSH_MSG_IGNORE: |
935 | break; | |
936 | case SSH_MSG_DEBUG: | |
937 | msg = packet_get_string(NULL); | |
938 | debug("Remote: %.900s", msg); | |
939 | xfree(msg); | |
940 | break; | |
941 | case SSH_MSG_DISCONNECT: | |
942 | msg = packet_get_string(NULL); | |
7c49df64 | 943 | log("Received disconnect from %s: %.400s", get_remote_ipaddr(), |
944 | msg); | |
7e7327a1 | 945 | fatal_cleanup(); |
946 | xfree(msg); | |
947 | break; | |
948 | default: | |
08dcb5d7 | 949 | if (type) |
7e7327a1 | 950 | DBG(debug("received packet type %d", type)); |
951 | return type; | |
952 | break; | |
2b87da3b | 953 | } |
7e7327a1 | 954 | } |
955 | } | |
956 | } | |
957 | ||
24ca6821 | 958 | int |
54a5250f | 959 | packet_read_poll(void) |
24ca6821 | 960 | { |
54a5250f | 961 | return packet_read_poll_seqnr(NULL); |
24ca6821 | 962 | } |
963 | ||
aa3378df | 964 | /* |
965 | * Buffers the given amount of input characters. This is intended to be used | |
966 | * together with packet_read_poll. | |
967 | */ | |
8efc0c15 | 968 | |
969 | void | |
1e3b8b07 | 970 | packet_process_incoming(const char *buf, u_int len) |
8efc0c15 | 971 | { |
5260325f | 972 | buffer_append(&input, buf, len); |
8efc0c15 | 973 | } |
974 | ||
975 | /* Returns a character from the packet. */ | |
976 | ||
1e3b8b07 | 977 | u_int |
d5bb9418 | 978 | packet_get_char(void) |
8efc0c15 | 979 | { |
5260325f | 980 | char ch; |
981 | buffer_get(&incoming_packet, &ch, 1); | |
1e3b8b07 | 982 | return (u_char) ch; |
8efc0c15 | 983 | } |
984 | ||
985 | /* Returns an integer from the packet data. */ | |
986 | ||
1e3b8b07 | 987 | u_int |
d5bb9418 | 988 | packet_get_int(void) |
8efc0c15 | 989 | { |
5260325f | 990 | return buffer_get_int(&incoming_packet); |
8efc0c15 | 991 | } |
992 | ||
aa3378df | 993 | /* |
994 | * Returns an arbitrary precision integer from the packet data. The integer | |
995 | * must have been initialized before this call. | |
996 | */ | |
8efc0c15 | 997 | |
998 | void | |
20b279e6 | 999 | packet_get_bignum(BIGNUM * value) |
8efc0c15 | 1000 | { |
4ef6f649 | 1001 | buffer_get_bignum(&incoming_packet, value); |
8efc0c15 | 1002 | } |
1003 | ||
7e7327a1 | 1004 | void |
20b279e6 | 1005 | packet_get_bignum2(BIGNUM * value) |
7e7327a1 | 1006 | { |
4ef6f649 | 1007 | buffer_get_bignum2(&incoming_packet, value); |
7e7327a1 | 1008 | } |
1009 | ||
6c0fa2b1 | 1010 | void * |
7e7327a1 | 1011 | packet_get_raw(int *length_ptr) |
1012 | { | |
1013 | int bytes = buffer_len(&incoming_packet); | |
1014 | if (length_ptr != NULL) | |
1015 | *length_ptr = bytes; | |
1016 | return buffer_ptr(&incoming_packet); | |
1017 | } | |
1018 | ||
6ae2364d | 1019 | int |
1020 | packet_remaining(void) | |
1021 | { | |
1022 | return buffer_len(&incoming_packet); | |
1023 | } | |
1024 | ||
aa3378df | 1025 | /* |
1026 | * Returns a string from the packet data. The string is allocated using | |
1027 | * xmalloc; it is the responsibility of the calling program to free it when | |
1028 | * no longer needed. The length_ptr argument may be NULL, or point to an | |
1029 | * integer into which the length of the string is stored. | |
1030 | */ | |
8efc0c15 | 1031 | |
6c0fa2b1 | 1032 | void * |
1e3b8b07 | 1033 | packet_get_string(u_int *length_ptr) |
8efc0c15 | 1034 | { |
5260325f | 1035 | return buffer_get_string(&incoming_packet, length_ptr); |
8efc0c15 | 1036 | } |
1037 | ||
aa3378df | 1038 | /* |
1039 | * Sends a diagnostic message from the server to the client. This message | |
1040 | * can be sent at any time (but not while constructing another message). The | |
1041 | * message is printed immediately, but only if the client is being executed | |
1042 | * in verbose mode. These messages are primarily intended to ease debugging | |
1043 | * authentication problems. The length of the formatted message must not | |
1044 | * exceed 1024 bytes. This will automatically call packet_write_wait. | |
1045 | */ | |
8efc0c15 | 1046 | |
1047 | void | |
5260325f | 1048 | packet_send_debug(const char *fmt,...) |
8efc0c15 | 1049 | { |
5260325f | 1050 | char buf[1024]; |
1051 | va_list args; | |
1052 | ||
f72fc97f | 1053 | if (compat20 && (datafellows & SSH_BUG_DEBUG)) |
1054 | return; | |
1055 | ||
5260325f | 1056 | va_start(args, fmt); |
1057 | vsnprintf(buf, sizeof(buf), fmt, args); | |
1058 | va_end(args); | |
1059 | ||
c4bc58eb | 1060 | if (compat20) { |
1061 | packet_start(SSH2_MSG_DEBUG); | |
1062 | packet_put_char(0); /* bool: always display */ | |
1063 | packet_put_cstring(buf); | |
1064 | packet_put_cstring(""); | |
1065 | } else { | |
1066 | packet_start(SSH_MSG_DEBUG); | |
1067 | packet_put_cstring(buf); | |
1068 | } | |
5260325f | 1069 | packet_send(); |
1070 | packet_write_wait(); | |
8efc0c15 | 1071 | } |
1072 | ||
aa3378df | 1073 | /* |
1074 | * Logs the error plus constructs and sends a disconnect packet, closes the | |
1075 | * connection, and exits. This function never returns. The error message | |
1076 | * should not contain a newline. The length of the formatted message must | |
1077 | * not exceed 1024 bytes. | |
1078 | */ | |
8efc0c15 | 1079 | |
1080 | void | |
5260325f | 1081 | packet_disconnect(const char *fmt,...) |
1082 | { | |
1083 | char buf[1024]; | |
1084 | va_list args; | |
1085 | static int disconnecting = 0; | |
1086 | if (disconnecting) /* Guard against recursive invocations. */ | |
1087 | fatal("packet_disconnect called recursively."); | |
1088 | disconnecting = 1; | |
1089 | ||
aa3378df | 1090 | /* |
1091 | * Format the message. Note that the caller must make sure the | |
1092 | * message is of limited size. | |
1093 | */ | |
5260325f | 1094 | va_start(args, fmt); |
1095 | vsnprintf(buf, sizeof(buf), fmt, args); | |
1096 | va_end(args); | |
1097 | ||
1098 | /* Send the disconnect message to the other side, and wait for it to get sent. */ | |
7e7327a1 | 1099 | if (compat20) { |
1100 | packet_start(SSH2_MSG_DISCONNECT); | |
1101 | packet_put_int(SSH2_DISCONNECT_PROTOCOL_ERROR); | |
1102 | packet_put_cstring(buf); | |
1103 | packet_put_cstring(""); | |
1104 | } else { | |
1105 | packet_start(SSH_MSG_DISCONNECT); | |
449c5ba5 | 1106 | packet_put_cstring(buf); |
7e7327a1 | 1107 | } |
5260325f | 1108 | packet_send(); |
1109 | packet_write_wait(); | |
1110 | ||
1111 | /* Stop listening for connections. */ | |
d6746a0b | 1112 | channel_close_all(); |
5260325f | 1113 | |
1114 | /* Close the connection. */ | |
1115 | packet_close(); | |
1116 | ||
1117 | /* Display the error locally and exit. */ | |
57112b5a | 1118 | log("Disconnecting: %.100s", buf); |
1119 | fatal_cleanup(); | |
8efc0c15 | 1120 | } |
1121 | ||
aa3378df | 1122 | /* Checks if there is any buffered output, and tries to write some of the output. */ |
8efc0c15 | 1123 | |
1124 | void | |
d5bb9418 | 1125 | packet_write_poll(void) |
8efc0c15 | 1126 | { |
5260325f | 1127 | int len = buffer_len(&output); |
1128 | if (len > 0) { | |
1129 | len = write(connection_out, buffer_ptr(&output), len); | |
1130 | if (len <= 0) { | |
1131 | if (errno == EAGAIN) | |
1132 | return; | |
1133 | else | |
1134 | fatal("Write failed: %.100s", strerror(errno)); | |
1135 | } | |
1136 | buffer_consume(&output, len); | |
1137 | } | |
8efc0c15 | 1138 | } |
1139 | ||
aa3378df | 1140 | /* |
1141 | * Calls packet_write_poll repeatedly until all pending output data has been | |
1142 | * written. | |
1143 | */ | |
8efc0c15 | 1144 | |
1145 | void | |
d5bb9418 | 1146 | packet_write_wait(void) |
8efc0c15 | 1147 | { |
20e04e90 | 1148 | fd_set *setp; |
1149 | ||
1150 | setp = (fd_set *)xmalloc(howmany(connection_out + 1, NFDBITS) * | |
1151 | sizeof(fd_mask)); | |
5260325f | 1152 | packet_write_poll(); |
1153 | while (packet_have_data_to_write()) { | |
20e04e90 | 1154 | memset(setp, 0, howmany(connection_out + 1, NFDBITS) * |
1155 | sizeof(fd_mask)); | |
1156 | FD_SET(connection_out, setp); | |
1157 | while (select(connection_out + 1, NULL, setp, NULL, NULL) == -1 && | |
fd193ca4 | 1158 | (errno == EAGAIN || errno == EINTR)) |
1159 | ; | |
5260325f | 1160 | packet_write_poll(); |
1161 | } | |
20e04e90 | 1162 | xfree(setp); |
8efc0c15 | 1163 | } |
1164 | ||
1165 | /* Returns true if there is buffered data to write to the connection. */ | |
1166 | ||
1167 | int | |
d5bb9418 | 1168 | packet_have_data_to_write(void) |
8efc0c15 | 1169 | { |
5260325f | 1170 | return buffer_len(&output) != 0; |
8efc0c15 | 1171 | } |
1172 | ||
1173 | /* Returns true if there is not too much data to write to the connection. */ | |
1174 | ||
1175 | int | |
d5bb9418 | 1176 | packet_not_very_much_data_to_write(void) |
8efc0c15 | 1177 | { |
5260325f | 1178 | if (interactive_mode) |
1179 | return buffer_len(&output) < 16384; | |
1180 | else | |
1181 | return buffer_len(&output) < 128 * 1024; | |
8efc0c15 | 1182 | } |
1183 | ||
1184 | /* Informs that the current session is interactive. Sets IP flags for that. */ | |
1185 | ||
1186 | void | |
b5c334cc | 1187 | packet_set_interactive(int interactive) |
8efc0c15 | 1188 | { |
b5c334cc | 1189 | static int called = 0; |
64e0e67e | 1190 | #if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN) |
b5c334cc | 1191 | int lowdelay = IPTOS_LOWDELAY; |
1192 | int throughput = IPTOS_THROUGHPUT; | |
64e0e67e | 1193 | #endif |
5260325f | 1194 | |
b5c334cc | 1195 | if (called) |
1196 | return; | |
1197 | called = 1; | |
1198 | ||
5260325f | 1199 | /* Record that we are in interactive mode. */ |
1200 | interactive_mode = interactive; | |
1201 | ||
48e671d5 | 1202 | /* Only set socket options if using a socket. */ |
1203 | if (!packet_connection_is_on_socket()) | |
5260325f | 1204 | return; |
48e671d5 | 1205 | /* |
f546c780 | 1206 | * IPTOS_LOWDELAY and IPTOS_THROUGHPUT are IPv4 only |
48e671d5 | 1207 | */ |
5260325f | 1208 | if (interactive) { |
aa3378df | 1209 | /* |
1210 | * Set IP options for an interactive connection. Use | |
1211 | * IPTOS_LOWDELAY and TCP_NODELAY. | |
1212 | */ | |
132dd316 | 1213 | #if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN) |
f546c780 | 1214 | if (packet_connection_is_ipv4()) { |
0e3c1f95 | 1215 | if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, |
f546c780 | 1216 | (void *) &lowdelay, sizeof(lowdelay)) < 0) |
0e3c1f95 | 1217 | error("setsockopt IPTOS_LOWDELAY: %.100s", |
f546c780 | 1218 | strerror(errno)); |
1219 | } | |
c04f75f1 | 1220 | #endif |
bcc0381e | 1221 | set_nodelay(connection_in); |
f546c780 | 1222 | } else if (packet_connection_is_ipv4()) { |
aa3378df | 1223 | /* |
1224 | * Set IP options for a non-interactive connection. Use | |
1225 | * IPTOS_THROUGHPUT. | |
1226 | */ | |
132dd316 | 1227 | #if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN) |
5260325f | 1228 | if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, (void *) &throughput, |
48e671d5 | 1229 | sizeof(throughput)) < 0) |
5260325f | 1230 | error("setsockopt IPTOS_THROUGHPUT: %.100s", strerror(errno)); |
c04f75f1 | 1231 | #endif |
5260325f | 1232 | } |
8efc0c15 | 1233 | } |
1234 | ||
1235 | /* Returns true if the current connection is interactive. */ | |
1236 | ||
1237 | int | |
d5bb9418 | 1238 | packet_is_interactive(void) |
8efc0c15 | 1239 | { |
5260325f | 1240 | return interactive_mode; |
8efc0c15 | 1241 | } |
9d6b7add | 1242 | |
1243 | int | |
1244 | packet_set_maxsize(int s) | |
1245 | { | |
5260325f | 1246 | static int called = 0; |
1247 | if (called) { | |
7e7327a1 | 1248 | log("packet_set_maxsize: called twice: old %d new %d", |
1249 | max_packet_size, s); | |
5260325f | 1250 | return -1; |
1251 | } | |
1252 | if (s < 4 * 1024 || s > 1024 * 1024) { | |
1253 | log("packet_set_maxsize: bad size %d", s); | |
1254 | return -1; | |
1255 | } | |
b6350327 | 1256 | called = 1; |
76735fe3 | 1257 | debug("packet_set_maxsize: setting to %d", s); |
5260325f | 1258 | max_packet_size = s; |
1259 | return s; | |
9d6b7add | 1260 | } |
a6215e53 | 1261 | |
b4b701be | 1262 | /* roundup current message to pad bytes */ |
1263 | void | |
1264 | packet_add_padding(u_char pad) | |
1265 | { | |
1266 | extra_pad = pad; | |
1267 | } | |
1268 | ||
a6215e53 | 1269 | /* |
1270 | * 9.2. Ignored Data Message | |
cd332296 | 1271 | * |
a6215e53 | 1272 | * byte SSH_MSG_IGNORE |
1273 | * string data | |
cd332296 | 1274 | * |
a6215e53 | 1275 | * All implementations MUST understand (and ignore) this message at any |
1276 | * time (after receiving the protocol version). No implementation is | |
1277 | * required to send them. This message can be used as an additional | |
1278 | * protection measure against advanced traffic analysis techniques. | |
1279 | */ | |
95ce5599 | 1280 | void |
1281 | packet_send_ignore(int nbytes) | |
1282 | { | |
1283 | u_int32_t rand = 0; | |
1284 | int i; | |
1285 | ||
1286 | packet_start(compat20 ? SSH2_MSG_IGNORE : SSH_MSG_IGNORE); | |
a6215e53 | 1287 | packet_put_int(nbytes); |
184eed6a | 1288 | for (i = 0; i < nbytes; i++) { |
a6215e53 | 1289 | if (i % 4 == 0) |
1290 | rand = arc4random(); | |
1291 | packet_put_char(rand & 0xff); | |
1292 | rand >>= 8; | |
1293 | } | |
1294 | } |