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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" | |
2ac91be1 | 40 | RCSID("$OpenBSD: packet.c,v 1.87 2002/01/24 21:13:23 stevesk Exp $"); |
8efc0c15 | 41 | |
42 | #include "xmalloc.h" | |
43 | #include "buffer.h" | |
44 | #include "packet.h" | |
45 | #include "bufaux.h" | |
8efc0c15 | 46 | #include "crc32.h" |
8efc0c15 | 47 | #include "getput.h" |
48 | ||
49 | #include "compress.h" | |
50 | #include "deattack.h" | |
a5efa1bb | 51 | #include "channels.h" |
8efc0c15 | 52 | |
7e7327a1 | 53 | #include "compat.h" |
42f11eb2 | 54 | #include "ssh1.h" |
7e7327a1 | 55 | #include "ssh2.h" |
56 | ||
94ec8c6b | 57 | #include "cipher.h" |
7e7327a1 | 58 | #include "kex.h" |
b2552997 | 59 | #include "mac.h" |
42f11eb2 | 60 | #include "log.h" |
61 | #include "canohost.h" | |
2ac91be1 | 62 | #include "misc.h" |
7e7327a1 | 63 | |
64 | #ifdef PACKET_DEBUG | |
65 | #define DBG(x) x | |
66 | #else | |
67 | #define DBG(x) | |
68 | #endif | |
69 | ||
aa3378df | 70 | /* |
71 | * This variable contains the file descriptors used for communicating with | |
72 | * the other side. connection_in is used for reading; connection_out for | |
73 | * writing. These can be the same descriptor, in which case it is assumed to | |
74 | * be a socket. | |
75 | */ | |
8efc0c15 | 76 | static int connection_in = -1; |
77 | static int connection_out = -1; | |
78 | ||
8efc0c15 | 79 | /* Protocol flags for the remote side. */ |
1e3b8b07 | 80 | static u_int remote_protocol_flags = 0; |
8efc0c15 | 81 | |
82 | /* Encryption context for receiving data. This is only used for decryption. */ | |
83 | static CipherContext receive_context; | |
5260325f | 84 | |
85 | /* Encryption context for sending data. This is only used for encryption. */ | |
8efc0c15 | 86 | static CipherContext send_context; |
87 | ||
88 | /* Buffer for raw input data from the socket. */ | |
89 | static Buffer input; | |
90 | ||
91 | /* Buffer for raw output data going to the socket. */ | |
92 | static Buffer output; | |
93 | ||
94 | /* Buffer for the partial outgoing packet being constructed. */ | |
95 | static Buffer outgoing_packet; | |
96 | ||
97 | /* Buffer for the incoming packet currently being processed. */ | |
98 | static Buffer incoming_packet; | |
99 | ||
100 | /* Scratch buffer for packet compression/decompression. */ | |
101 | static Buffer compression_buffer; | |
6ba22c93 | 102 | static int compression_buffer_ready = 0; |
8efc0c15 | 103 | |
104 | /* Flag indicating whether packet compression/decompression is enabled. */ | |
105 | static int packet_compression = 0; | |
106 | ||
9d6b7add | 107 | /* default maximum packet size */ |
108 | int max_packet_size = 32768; | |
109 | ||
8efc0c15 | 110 | /* Flag indicating whether this module has been initialized. */ |
111 | static int initialized = 0; | |
112 | ||
113 | /* Set to true if the connection is interactive. */ | |
114 | static int interactive_mode = 0; | |
115 | ||
7e7327a1 | 116 | /* Session key information for Encryption and MAC */ |
d1ac6175 | 117 | Newkeys *newkeys[MODE_MAX]; |
7e7327a1 | 118 | |
b4b701be | 119 | /* roundup current message to extra_pad bytes */ |
120 | static u_char extra_pad = 0; | |
121 | ||
aa3378df | 122 | /* |
123 | * Sets the descriptors used for communication. Disables encryption until | |
124 | * packet_set_encryption_key is called. | |
125 | */ | |
8efc0c15 | 126 | void |
127 | packet_set_connection(int fd_in, int fd_out) | |
128 | { | |
94ec8c6b | 129 | Cipher *none = cipher_by_name("none"); |
130 | if (none == NULL) | |
131 | fatal("packet_set_connection: cannot load cipher 'none'"); | |
5260325f | 132 | connection_in = fd_in; |
133 | connection_out = fd_out; | |
e6207598 | 134 | cipher_init(&send_context, none, "", 0, NULL, 0); |
135 | cipher_init(&receive_context, none, "", 0, NULL, 0); | |
08dcb5d7 | 136 | newkeys[MODE_IN] = newkeys[MODE_OUT] = NULL; |
5260325f | 137 | if (!initialized) { |
138 | initialized = 1; | |
139 | buffer_init(&input); | |
140 | buffer_init(&output); | |
141 | buffer_init(&outgoing_packet); | |
142 | buffer_init(&incoming_packet); | |
143 | } | |
144 | /* Kludge: arrange the close function to be called from fatal(). */ | |
145 | fatal_add_cleanup((void (*) (void *)) packet_close, NULL); | |
8efc0c15 | 146 | } |
147 | ||
48e671d5 | 148 | /* Returns 1 if remote host is connected via socket, 0 if not. */ |
149 | ||
150 | int | |
d5bb9418 | 151 | packet_connection_is_on_socket(void) |
48e671d5 | 152 | { |
153 | struct sockaddr_storage from, to; | |
154 | socklen_t fromlen, tolen; | |
155 | ||
156 | /* filedescriptors in and out are the same, so it's a socket */ | |
157 | if (connection_in == connection_out) | |
158 | return 1; | |
159 | fromlen = sizeof(from); | |
160 | memset(&from, 0, sizeof(from)); | |
9bc5ddfe | 161 | if (getpeername(connection_in, (struct sockaddr *)&from, &fromlen) < 0) |
48e671d5 | 162 | return 0; |
163 | tolen = sizeof(to); | |
164 | memset(&to, 0, sizeof(to)); | |
9bc5ddfe | 165 | if (getpeername(connection_out, (struct sockaddr *)&to, &tolen) < 0) |
48e671d5 | 166 | return 0; |
167 | if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0) | |
168 | return 0; | |
169 | if (from.ss_family != AF_INET && from.ss_family != AF_INET6) | |
170 | return 0; | |
171 | return 1; | |
172 | } | |
173 | ||
174 | /* returns 1 if connection is via ipv4 */ | |
175 | ||
176 | int | |
d5bb9418 | 177 | packet_connection_is_ipv4(void) |
48e671d5 | 178 | { |
179 | struct sockaddr_storage to; | |
d45317d8 | 180 | socklen_t tolen = sizeof(to); |
48e671d5 | 181 | |
182 | memset(&to, 0, sizeof(to)); | |
183 | if (getsockname(connection_out, (struct sockaddr *)&to, &tolen) < 0) | |
184 | return 0; | |
185 | if (to.ss_family != AF_INET) | |
186 | return 0; | |
187 | return 1; | |
188 | } | |
189 | ||
8efc0c15 | 190 | /* Sets the connection into non-blocking mode. */ |
191 | ||
192 | void | |
d5bb9418 | 193 | packet_set_nonblocking(void) |
8efc0c15 | 194 | { |
5260325f | 195 | /* Set the socket into non-blocking mode. */ |
196 | if (fcntl(connection_in, F_SETFL, O_NONBLOCK) < 0) | |
197 | error("fcntl O_NONBLOCK: %.100s", strerror(errno)); | |
8efc0c15 | 198 | |
5260325f | 199 | if (connection_out != connection_in) { |
200 | if (fcntl(connection_out, F_SETFL, O_NONBLOCK) < 0) | |
201 | error("fcntl O_NONBLOCK: %.100s", strerror(errno)); | |
202 | } | |
8efc0c15 | 203 | } |
204 | ||
205 | /* Returns the socket used for reading. */ | |
206 | ||
207 | int | |
d5bb9418 | 208 | packet_get_connection_in(void) |
8efc0c15 | 209 | { |
5260325f | 210 | return connection_in; |
8efc0c15 | 211 | } |
212 | ||
213 | /* Returns the descriptor used for writing. */ | |
214 | ||
215 | int | |
d5bb9418 | 216 | packet_get_connection_out(void) |
8efc0c15 | 217 | { |
5260325f | 218 | return connection_out; |
8efc0c15 | 219 | } |
220 | ||
221 | /* Closes the connection and clears and frees internal data structures. */ | |
222 | ||
223 | void | |
d5bb9418 | 224 | packet_close(void) |
8efc0c15 | 225 | { |
5260325f | 226 | if (!initialized) |
227 | return; | |
228 | initialized = 0; | |
229 | if (connection_in == connection_out) { | |
230 | shutdown(connection_out, SHUT_RDWR); | |
231 | close(connection_out); | |
232 | } else { | |
233 | close(connection_in); | |
234 | close(connection_out); | |
235 | } | |
236 | buffer_free(&input); | |
237 | buffer_free(&output); | |
238 | buffer_free(&outgoing_packet); | |
239 | buffer_free(&incoming_packet); | |
6ba22c93 | 240 | if (compression_buffer_ready) { |
5260325f | 241 | buffer_free(&compression_buffer); |
242 | buffer_compress_uninit(); | |
243 | } | |
8efc0c15 | 244 | } |
245 | ||
246 | /* Sets remote side protocol flags. */ | |
247 | ||
248 | void | |
1e3b8b07 | 249 | packet_set_protocol_flags(u_int protocol_flags) |
8efc0c15 | 250 | { |
5260325f | 251 | remote_protocol_flags = protocol_flags; |
8efc0c15 | 252 | } |
253 | ||
254 | /* Returns the remote protocol flags set earlier by the above function. */ | |
255 | ||
1e3b8b07 | 256 | u_int |
d5bb9418 | 257 | packet_get_protocol_flags(void) |
8efc0c15 | 258 | { |
5260325f | 259 | return remote_protocol_flags; |
8efc0c15 | 260 | } |
261 | ||
aa3378df | 262 | /* |
263 | * Starts packet compression from the next packet on in both directions. | |
264 | * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip. | |
265 | */ | |
8efc0c15 | 266 | |
396c147e | 267 | static void |
268 | packet_init_compression(void) | |
6ba22c93 | 269 | { |
270 | if (compression_buffer_ready == 1) | |
271 | return; | |
272 | compression_buffer_ready = 1; | |
273 | buffer_init(&compression_buffer); | |
274 | } | |
275 | ||
8efc0c15 | 276 | void |
277 | packet_start_compression(int level) | |
278 | { | |
08dcb5d7 | 279 | if (packet_compression && !compat20) |
5260325f | 280 | fatal("Compression already enabled."); |
281 | packet_compression = 1; | |
6ba22c93 | 282 | packet_init_compression(); |
283 | buffer_compress_init_send(level); | |
284 | buffer_compress_init_recv(); | |
8efc0c15 | 285 | } |
286 | ||
aa3378df | 287 | /* |
288 | * Causes any further packets to be encrypted using the given key. The same | |
289 | * key is used for both sending and reception. However, both directions are | |
290 | * encrypted independently of each other. | |
291 | */ | |
8efc0c15 | 292 | void |
1e3b8b07 | 293 | packet_set_encryption_key(const u_char *key, u_int keylen, |
94ec8c6b | 294 | int number) |
8efc0c15 | 295 | { |
94ec8c6b | 296 | Cipher *cipher = cipher_by_number(number); |
297 | if (cipher == NULL) | |
298 | fatal("packet_set_encryption_key: unknown cipher number %d", number); | |
7e7327a1 | 299 | if (keylen < 20) |
94ec8c6b | 300 | fatal("packet_set_encryption_key: keylen too small: %d", keylen); |
301 | cipher_init(&receive_context, cipher, key, keylen, NULL, 0); | |
302 | cipher_init(&send_context, cipher, key, keylen, NULL, 0); | |
8efc0c15 | 303 | } |
304 | ||
08dcb5d7 | 305 | /* Start constructing a packet to send. */ |
8efc0c15 | 306 | void |
08dcb5d7 | 307 | packet_start(u_char type) |
8efc0c15 | 308 | { |
08dcb5d7 | 309 | u_char buf[9]; |
310 | int len; | |
7e7327a1 | 311 | |
12bf85ed | 312 | DBG(debug("packet_start[%d]", type)); |
08dcb5d7 | 313 | len = compat20 ? 6 : 9; |
314 | memset(buf, 0, len - 1); | |
315 | buf[len - 1] = type; | |
316 | buffer_clear(&outgoing_packet); | |
317 | buffer_append(&outgoing_packet, buf, len); | |
7e7327a1 | 318 | } |
319 | ||
08dcb5d7 | 320 | /* Append payload. */ |
8efc0c15 | 321 | void |
322 | packet_put_char(int value) | |
323 | { | |
5260325f | 324 | char ch = value; |
325 | buffer_append(&outgoing_packet, &ch, 1); | |
8efc0c15 | 326 | } |
8efc0c15 | 327 | void |
1e3b8b07 | 328 | packet_put_int(u_int value) |
8efc0c15 | 329 | { |
5260325f | 330 | buffer_put_int(&outgoing_packet, value); |
8efc0c15 | 331 | } |
8efc0c15 | 332 | void |
6c0fa2b1 | 333 | packet_put_string(const void *buf, u_int len) |
8efc0c15 | 334 | { |
5260325f | 335 | buffer_put_string(&outgoing_packet, buf, len); |
8efc0c15 | 336 | } |
7e7327a1 | 337 | void |
338 | packet_put_cstring(const char *str) | |
339 | { | |
449c5ba5 | 340 | buffer_put_cstring(&outgoing_packet, str); |
7e7327a1 | 341 | } |
7e7327a1 | 342 | void |
6c0fa2b1 | 343 | packet_put_raw(const void *buf, u_int len) |
7e7327a1 | 344 | { |
345 | buffer_append(&outgoing_packet, buf, len); | |
346 | } | |
8efc0c15 | 347 | void |
5260325f | 348 | packet_put_bignum(BIGNUM * value) |
8efc0c15 | 349 | { |
5260325f | 350 | buffer_put_bignum(&outgoing_packet, value); |
8efc0c15 | 351 | } |
7e7327a1 | 352 | void |
353 | packet_put_bignum2(BIGNUM * value) | |
354 | { | |
355 | buffer_put_bignum2(&outgoing_packet, value); | |
356 | } | |
8efc0c15 | 357 | |
aa3378df | 358 | /* |
359 | * Finalizes and sends the packet. If the encryption key has been set, | |
360 | * encrypts the packet before sending. | |
361 | */ | |
5260325f | 362 | |
396c147e | 363 | static void |
5ca51e19 | 364 | packet_send1(void) |
8efc0c15 | 365 | { |
5260325f | 366 | char buf[8], *cp; |
367 | int i, padding, len; | |
1e3b8b07 | 368 | u_int checksum; |
5260325f | 369 | u_int32_t rand = 0; |
370 | ||
aa3378df | 371 | /* |
372 | * If using packet compression, compress the payload of the outgoing | |
373 | * packet. | |
374 | */ | |
5260325f | 375 | if (packet_compression) { |
376 | buffer_clear(&compression_buffer); | |
377 | /* Skip padding. */ | |
378 | buffer_consume(&outgoing_packet, 8); | |
379 | /* padding */ | |
380 | buffer_append(&compression_buffer, "\0\0\0\0\0\0\0\0", 8); | |
381 | buffer_compress(&outgoing_packet, &compression_buffer); | |
382 | buffer_clear(&outgoing_packet); | |
383 | buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer), | |
184eed6a | 384 | buffer_len(&compression_buffer)); |
5260325f | 385 | } |
386 | /* Compute packet length without padding (add checksum, remove padding). */ | |
387 | len = buffer_len(&outgoing_packet) + 4 - 8; | |
388 | ||
1d1ffb87 | 389 | /* Insert padding. Initialized to zero in packet_start1() */ |
5260325f | 390 | padding = 8 - len % 8; |
08dcb5d7 | 391 | if (send_context.cipher->number != SSH_CIPHER_NONE) { |
5260325f | 392 | cp = buffer_ptr(&outgoing_packet); |
393 | for (i = 0; i < padding; i++) { | |
394 | if (i % 4 == 0) | |
395 | rand = arc4random(); | |
396 | cp[7 - i] = rand & 0xff; | |
397 | rand >>= 8; | |
398 | } | |
399 | } | |
400 | buffer_consume(&outgoing_packet, 8 - padding); | |
401 | ||
402 | /* Add check bytes. */ | |
20905a8e | 403 | checksum = ssh_crc32(buffer_ptr(&outgoing_packet), |
2e73a022 | 404 | buffer_len(&outgoing_packet)); |
5260325f | 405 | PUT_32BIT(buf, checksum); |
406 | buffer_append(&outgoing_packet, buf, 4); | |
8efc0c15 | 407 | |
408 | #ifdef PACKET_DEBUG | |
5260325f | 409 | fprintf(stderr, "packet_send plain: "); |
410 | buffer_dump(&outgoing_packet); | |
8efc0c15 | 411 | #endif |
412 | ||
5260325f | 413 | /* Append to output. */ |
414 | PUT_32BIT(buf, len); | |
415 | buffer_append(&output, buf, 4); | |
6c0fa2b1 | 416 | cp = buffer_append_space(&output, buffer_len(&outgoing_packet)); |
08dcb5d7 | 417 | cipher_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet), |
184eed6a | 418 | buffer_len(&outgoing_packet)); |
5260325f | 419 | |
8efc0c15 | 420 | #ifdef PACKET_DEBUG |
5260325f | 421 | fprintf(stderr, "encrypted: "); |
422 | buffer_dump(&output); | |
8efc0c15 | 423 | #endif |
424 | ||
5260325f | 425 | buffer_clear(&outgoing_packet); |
8efc0c15 | 426 | |
aa3378df | 427 | /* |
428 | * Note that the packet is now only buffered in output. It won\'t be | |
429 | * actually sent until packet_write_wait or packet_write_poll is | |
430 | * called. | |
431 | */ | |
8efc0c15 | 432 | } |
433 | ||
396c147e | 434 | static void |
d1ac6175 | 435 | set_newkeys(int mode) |
436 | { | |
437 | Enc *enc; | |
438 | Mac *mac; | |
439 | Comp *comp; | |
440 | CipherContext *cc; | |
441 | ||
442 | debug("newkeys: mode %d", mode); | |
443 | ||
444 | cc = (mode == MODE_OUT) ? &send_context : &receive_context; | |
445 | if (newkeys[mode] != NULL) { | |
446 | debug("newkeys: rekeying"); | |
d8ee838b | 447 | /* todo: free old keys, reset compression/cipher-ctxt; */ |
a7ca6275 | 448 | memset(cc, 0, sizeof(*cc)); |
449 | enc = &newkeys[mode]->enc; | |
450 | mac = &newkeys[mode]->mac; | |
451 | comp = &newkeys[mode]->comp; | |
cd332296 | 452 | memset(mac->key, 0, mac->key_len); |
a7ca6275 | 453 | xfree(enc->name); |
454 | xfree(enc->iv); | |
455 | xfree(enc->key); | |
456 | xfree(mac->name); | |
457 | xfree(mac->key); | |
458 | xfree(comp->name); | |
d8ee838b | 459 | xfree(newkeys[mode]); |
d1ac6175 | 460 | } |
461 | newkeys[mode] = kex_get_newkeys(mode); | |
462 | if (newkeys[mode] == NULL) | |
463 | fatal("newkeys: no keys for mode %d", mode); | |
464 | enc = &newkeys[mode]->enc; | |
465 | mac = &newkeys[mode]->mac; | |
466 | comp = &newkeys[mode]->comp; | |
467 | if (mac->md != NULL) | |
468 | mac->enabled = 1; | |
469 | DBG(debug("cipher_init_context: %d", mode)); | |
470 | cipher_init(cc, enc->cipher, enc->key, enc->cipher->key_len, | |
471 | enc->iv, enc->cipher->block_size); | |
a7ca6275 | 472 | memset(enc->iv, 0, enc->cipher->block_size); |
473 | memset(enc->key, 0, enc->cipher->key_len); | |
d1ac6175 | 474 | if (comp->type != 0 && comp->enabled == 0) { |
6ba22c93 | 475 | packet_init_compression(); |
476 | if (mode == MODE_OUT) | |
477 | buffer_compress_init_send(6); | |
478 | else | |
479 | buffer_compress_init_recv(); | |
d1ac6175 | 480 | comp->enabled = 1; |
d1ac6175 | 481 | } |
482 | } | |
483 | ||
7e7327a1 | 484 | /* |
485 | * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue) | |
486 | */ | |
396c147e | 487 | static void |
5ca51e19 | 488 | packet_send2(void) |
7e7327a1 | 489 | { |
b2552997 | 490 | static u_int32_t seqnr = 0; |
08dcb5d7 | 491 | u_char type, *ucp, *macbuf = NULL; |
b4b701be | 492 | u_char padlen, pad; |
7e7327a1 | 493 | char *cp; |
1e3b8b07 | 494 | u_int packet_length = 0; |
b4b701be | 495 | u_int i, len; |
7e7327a1 | 496 | u_int32_t rand = 0; |
7e7327a1 | 497 | Enc *enc = NULL; |
498 | Mac *mac = NULL; | |
499 | Comp *comp = NULL; | |
500 | int block_size; | |
501 | ||
d1ac6175 | 502 | if (newkeys[MODE_OUT] != NULL) { |
503 | enc = &newkeys[MODE_OUT]->enc; | |
504 | mac = &newkeys[MODE_OUT]->mac; | |
505 | comp = &newkeys[MODE_OUT]->comp; | |
7e7327a1 | 506 | } |
94ec8c6b | 507 | block_size = enc ? enc->cipher->block_size : 8; |
7e7327a1 | 508 | |
20905a8e | 509 | ucp = buffer_ptr(&outgoing_packet); |
08dcb5d7 | 510 | type = ucp[5]; |
7e7327a1 | 511 | |
512 | #ifdef PACKET_DEBUG | |
513 | fprintf(stderr, "plain: "); | |
514 | buffer_dump(&outgoing_packet); | |
515 | #endif | |
516 | ||
517 | if (comp && comp->enabled) { | |
518 | len = buffer_len(&outgoing_packet); | |
519 | /* skip header, compress only payload */ | |
520 | buffer_consume(&outgoing_packet, 5); | |
521 | buffer_clear(&compression_buffer); | |
522 | buffer_compress(&outgoing_packet, &compression_buffer); | |
523 | buffer_clear(&outgoing_packet); | |
524 | buffer_append(&outgoing_packet, "\0\0\0\0\0", 5); | |
525 | buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer), | |
526 | buffer_len(&compression_buffer)); | |
527 | DBG(debug("compression: raw %d compressed %d", len, | |
528 | buffer_len(&outgoing_packet))); | |
529 | } | |
530 | ||
531 | /* sizeof (packet_len + pad_len + payload) */ | |
532 | len = buffer_len(&outgoing_packet); | |
533 | ||
534 | /* | |
535 | * calc size of padding, alloc space, get random data, | |
536 | * minimum padding is 4 bytes | |
537 | */ | |
538 | padlen = block_size - (len % block_size); | |
539 | if (padlen < 4) | |
540 | padlen += block_size; | |
b4b701be | 541 | if (extra_pad) { |
542 | /* will wrap if extra_pad+padlen > 255 */ | |
543 | extra_pad = roundup(extra_pad, block_size); | |
544 | pad = extra_pad - ((len + padlen) % extra_pad); | |
545 | debug("packet_send2: adding %d (len %d padlen %d extra_pad %d)", | |
546 | pad, len, padlen, extra_pad); | |
547 | padlen += pad; | |
548 | extra_pad = 0; | |
549 | } | |
6c0fa2b1 | 550 | cp = buffer_append_space(&outgoing_packet, padlen); |
94ec8c6b | 551 | if (enc && enc->cipher->number != SSH_CIPHER_NONE) { |
1d1ffb87 | 552 | /* random padding */ |
7e7327a1 | 553 | for (i = 0; i < padlen; i++) { |
554 | if (i % 4 == 0) | |
555 | rand = arc4random(); | |
556 | cp[i] = rand & 0xff; | |
6e18cb71 | 557 | rand >>= 8; |
7e7327a1 | 558 | } |
1d1ffb87 | 559 | } else { |
560 | /* clear padding */ | |
561 | memset(cp, 0, padlen); | |
7e7327a1 | 562 | } |
563 | /* packet_length includes payload, padding and padding length field */ | |
564 | packet_length = buffer_len(&outgoing_packet) - 4; | |
20905a8e | 565 | ucp = buffer_ptr(&outgoing_packet); |
08dcb5d7 | 566 | PUT_32BIT(ucp, packet_length); |
567 | ucp[4] = padlen; | |
7e7327a1 | 568 | DBG(debug("send: len %d (includes padlen %d)", packet_length+4, padlen)); |
569 | ||
570 | /* compute MAC over seqnr and packet(length fields, payload, padding) */ | |
571 | if (mac && mac->enabled) { | |
b2552997 | 572 | macbuf = mac_compute(mac, seqnr, |
20905a8e | 573 | buffer_ptr(&outgoing_packet), |
b2552997 | 574 | buffer_len(&outgoing_packet)); |
94ec8c6b | 575 | DBG(debug("done calc MAC out #%d", seqnr)); |
7e7327a1 | 576 | } |
577 | /* encrypt packet and append to output buffer. */ | |
6c0fa2b1 | 578 | cp = buffer_append_space(&output, buffer_len(&outgoing_packet)); |
08dcb5d7 | 579 | cipher_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet), |
7e7327a1 | 580 | buffer_len(&outgoing_packet)); |
581 | /* append unencrypted MAC */ | |
582 | if (mac && mac->enabled) | |
583 | buffer_append(&output, (char *)macbuf, mac->mac_len); | |
584 | #ifdef PACKET_DEBUG | |
585 | fprintf(stderr, "encrypted: "); | |
586 | buffer_dump(&output); | |
587 | #endif | |
6ae2364d | 588 | /* increment sequence number for outgoing packets */ |
589 | if (++seqnr == 0) | |
590 | log("outgoing seqnr wraps around"); | |
7e7327a1 | 591 | buffer_clear(&outgoing_packet); |
592 | ||
d1ac6175 | 593 | if (type == SSH2_MSG_NEWKEYS) |
594 | set_newkeys(MODE_OUT); | |
7e7327a1 | 595 | } |
596 | ||
597 | void | |
d5bb9418 | 598 | packet_send(void) |
7e7327a1 | 599 | { |
08dcb5d7 | 600 | if (compat20) |
7e7327a1 | 601 | packet_send2(); |
602 | else | |
603 | packet_send1(); | |
604 | DBG(debug("packet_send done")); | |
605 | } | |
606 | ||
aa3378df | 607 | /* |
608 | * Waits until a packet has been received, and returns its type. Note that | |
609 | * no other data is processed until this returns, so this function should not | |
610 | * be used during the interactive session. | |
611 | */ | |
8efc0c15 | 612 | |
613 | int | |
54a5250f | 614 | packet_read_seqnr(u_int32_t *seqnr_p) |
8efc0c15 | 615 | { |
5260325f | 616 | int type, len; |
20e04e90 | 617 | fd_set *setp; |
5260325f | 618 | char buf[8192]; |
7e7327a1 | 619 | DBG(debug("packet_read()")); |
5260325f | 620 | |
20e04e90 | 621 | setp = (fd_set *)xmalloc(howmany(connection_in+1, NFDBITS) * |
622 | sizeof(fd_mask)); | |
623 | ||
5260325f | 624 | /* Since we are blocking, ensure that all written packets have been sent. */ |
625 | packet_write_wait(); | |
626 | ||
627 | /* Stay in the loop until we have received a complete packet. */ | |
628 | for (;;) { | |
629 | /* Try to read a packet from the buffer. */ | |
54a5250f | 630 | type = packet_read_poll_seqnr(seqnr_p); |
08dcb5d7 | 631 | if (!compat20 && ( |
1d1ffb87 | 632 | type == SSH_SMSG_SUCCESS |
5260325f | 633 | || type == SSH_SMSG_FAILURE |
634 | || type == SSH_CMSG_EOF | |
1d1ffb87 | 635 | || type == SSH_CMSG_EXIT_CONFIRMATION)) |
95500969 | 636 | packet_check_eom(); |
5260325f | 637 | /* If we got a packet, return it. */ |
20e04e90 | 638 | if (type != SSH_MSG_NONE) { |
639 | xfree(setp); | |
5260325f | 640 | return type; |
20e04e90 | 641 | } |
aa3378df | 642 | /* |
643 | * Otherwise, wait for some data to arrive, add it to the | |
644 | * buffer, and try again. | |
645 | */ | |
20e04e90 | 646 | memset(setp, 0, howmany(connection_in + 1, NFDBITS) * |
647 | sizeof(fd_mask)); | |
648 | FD_SET(connection_in, setp); | |
aa3378df | 649 | |
5260325f | 650 | /* Wait for some data to arrive. */ |
20e04e90 | 651 | while (select(connection_in + 1, setp, NULL, NULL, NULL) == -1 && |
fd193ca4 | 652 | (errno == EAGAIN || errno == EINTR)) |
653 | ; | |
aa3378df | 654 | |
5260325f | 655 | /* Read data from the socket. */ |
656 | len = read(connection_in, buf, sizeof(buf)); | |
89cafde6 | 657 | if (len == 0) { |
658 | log("Connection closed by %.200s", get_remote_ipaddr()); | |
659 | fatal_cleanup(); | |
660 | } | |
5260325f | 661 | if (len < 0) |
662 | fatal("Read from socket failed: %.100s", strerror(errno)); | |
663 | /* Append it to the buffer. */ | |
664 | packet_process_incoming(buf, len); | |
665 | } | |
666 | /* NOTREACHED */ | |
8efc0c15 | 667 | } |
668 | ||
24ca6821 | 669 | int |
54a5250f | 670 | packet_read(void) |
24ca6821 | 671 | { |
54a5250f | 672 | return packet_read_seqnr(NULL); |
24ca6821 | 673 | } |
674 | ||
aa3378df | 675 | /* |
676 | * Waits until a packet has been received, verifies that its type matches | |
677 | * that given, and gives a fatal error and exits if there is a mismatch. | |
678 | */ | |
8efc0c15 | 679 | |
680 | void | |
54a5250f | 681 | packet_read_expect(int expected_type) |
8efc0c15 | 682 | { |
5260325f | 683 | int type; |
8efc0c15 | 684 | |
54a5250f | 685 | type = packet_read(); |
5260325f | 686 | if (type != expected_type) |
687 | packet_disconnect("Protocol error: expected packet type %d, got %d", | |
7e7327a1 | 688 | expected_type, type); |
8efc0c15 | 689 | } |
690 | ||
691 | /* Checks if a full packet is available in the data received so far via | |
5260325f | 692 | * packet_process_incoming. If so, reads the packet; otherwise returns |
693 | * SSH_MSG_NONE. This does not wait for data from the connection. | |
694 | * | |
695 | * SSH_MSG_DISCONNECT is handled specially here. Also, | |
696 | * SSH_MSG_IGNORE messages are skipped by this function and are never returned | |
697 | * to higher levels. | |
5260325f | 698 | */ |
8efc0c15 | 699 | |
396c147e | 700 | static int |
54a5250f | 701 | packet_read_poll1(void) |
8efc0c15 | 702 | { |
1e3b8b07 | 703 | u_int len, padded_len; |
08dcb5d7 | 704 | u_char *ucp, type; |
705 | char *cp; | |
1e3b8b07 | 706 | u_int checksum, stored_checksum; |
5260325f | 707 | |
5260325f | 708 | /* Check if input size is less than minimum packet size. */ |
709 | if (buffer_len(&input) < 4 + 8) | |
710 | return SSH_MSG_NONE; | |
711 | /* Get length of incoming packet. */ | |
20905a8e | 712 | ucp = buffer_ptr(&input); |
5260325f | 713 | len = GET_32BIT(ucp); |
714 | if (len < 1 + 2 + 2 || len > 256 * 1024) | |
715 | packet_disconnect("Bad packet length %d.", len); | |
716 | padded_len = (len + 8) & ~7; | |
717 | ||
718 | /* Check if the packet has been entirely received. */ | |
719 | if (buffer_len(&input) < 4 + padded_len) | |
720 | return SSH_MSG_NONE; | |
721 | ||
722 | /* The entire packet is in buffer. */ | |
723 | ||
724 | /* Consume packet length. */ | |
725 | buffer_consume(&input, 4); | |
726 | ||
08dcb5d7 | 727 | /* |
728 | * Cryptographic attack detector for ssh | |
729 | * (C)1998 CORE-SDI, Buenos Aires Argentina | |
730 | * Ariel Futoransky(futo@core-sdi.com) | |
731 | */ | |
732 | if (receive_context.cipher->number != SSH_CIPHER_NONE && | |
733 | detect_attack(buffer_ptr(&input), padded_len, NULL) == DEATTACK_DETECTED) | |
734 | packet_disconnect("crc32 compensation attack: network attack detected"); | |
735 | ||
736 | /* Decrypt data to incoming_packet. */ | |
5260325f | 737 | buffer_clear(&incoming_packet); |
6c0fa2b1 | 738 | cp = buffer_append_space(&incoming_packet, padded_len); |
08dcb5d7 | 739 | cipher_decrypt(&receive_context, cp, buffer_ptr(&input), padded_len); |
740 | ||
5260325f | 741 | buffer_consume(&input, padded_len); |
8efc0c15 | 742 | |
743 | #ifdef PACKET_DEBUG | |
5260325f | 744 | fprintf(stderr, "read_poll plain: "); |
745 | buffer_dump(&incoming_packet); | |
8efc0c15 | 746 | #endif |
5260325f | 747 | |
748 | /* Compute packet checksum. */ | |
20905a8e | 749 | checksum = ssh_crc32(buffer_ptr(&incoming_packet), |
7e7327a1 | 750 | buffer_len(&incoming_packet) - 4); |
5260325f | 751 | |
752 | /* Skip padding. */ | |
753 | buffer_consume(&incoming_packet, 8 - len % 8); | |
754 | ||
755 | /* Test check bytes. */ | |
5260325f | 756 | if (len != buffer_len(&incoming_packet)) |
24ca6821 | 757 | packet_disconnect("packet_read_poll1: len %d != buffer_len %d.", |
7e7327a1 | 758 | len, buffer_len(&incoming_packet)); |
5260325f | 759 | |
20905a8e | 760 | ucp = (u_char *)buffer_ptr(&incoming_packet) + len - 4; |
5260325f | 761 | stored_checksum = GET_32BIT(ucp); |
762 | if (checksum != stored_checksum) | |
763 | packet_disconnect("Corrupted check bytes on input."); | |
764 | buffer_consume_end(&incoming_packet, 4); | |
765 | ||
5260325f | 766 | if (packet_compression) { |
767 | buffer_clear(&compression_buffer); | |
768 | buffer_uncompress(&incoming_packet, &compression_buffer); | |
769 | buffer_clear(&incoming_packet); | |
770 | buffer_append(&incoming_packet, buffer_ptr(&compression_buffer), | |
7e7327a1 | 771 | buffer_len(&compression_buffer)); |
5260325f | 772 | } |
08dcb5d7 | 773 | type = buffer_get_char(&incoming_packet); |
08dcb5d7 | 774 | return type; |
5260325f | 775 | } |
776 | ||
396c147e | 777 | static int |
54a5250f | 778 | packet_read_poll2(u_int32_t *seqnr_p) |
7e7327a1 | 779 | { |
b2552997 | 780 | static u_int32_t seqnr = 0; |
781 | static u_int packet_length = 0; | |
1e3b8b07 | 782 | u_int padlen, need; |
08dcb5d7 | 783 | u_char *macbuf, *ucp, type; |
7e7327a1 | 784 | char *cp; |
7e7327a1 | 785 | int maclen, block_size; |
786 | Enc *enc = NULL; | |
787 | Mac *mac = NULL; | |
788 | Comp *comp = NULL; | |
789 | ||
d1ac6175 | 790 | if (newkeys[MODE_IN] != NULL) { |
791 | enc = &newkeys[MODE_IN]->enc; | |
792 | mac = &newkeys[MODE_IN]->mac; | |
793 | comp = &newkeys[MODE_IN]->comp; | |
7e7327a1 | 794 | } |
795 | maclen = mac && mac->enabled ? mac->mac_len : 0; | |
94ec8c6b | 796 | block_size = enc ? enc->cipher->block_size : 8; |
7e7327a1 | 797 | |
798 | if (packet_length == 0) { | |
799 | /* | |
800 | * check if input size is less than the cipher block size, | |
801 | * decrypt first block and extract length of incoming packet | |
802 | */ | |
803 | if (buffer_len(&input) < block_size) | |
804 | return SSH_MSG_NONE; | |
805 | buffer_clear(&incoming_packet); | |
6c0fa2b1 | 806 | cp = buffer_append_space(&incoming_packet, block_size); |
08dcb5d7 | 807 | cipher_decrypt(&receive_context, cp, buffer_ptr(&input), |
7e7327a1 | 808 | block_size); |
20905a8e | 809 | ucp = buffer_ptr(&incoming_packet); |
7e7327a1 | 810 | packet_length = GET_32BIT(ucp); |
811 | if (packet_length < 1 + 4 || packet_length > 256 * 1024) { | |
812 | buffer_dump(&incoming_packet); | |
813 | packet_disconnect("Bad packet length %d.", packet_length); | |
814 | } | |
815 | DBG(debug("input: packet len %d", packet_length+4)); | |
816 | buffer_consume(&input, block_size); | |
817 | } | |
818 | /* we have a partial packet of block_size bytes */ | |
819 | need = 4 + packet_length - block_size; | |
820 | DBG(debug("partial packet %d, need %d, maclen %d", block_size, | |
821 | need, maclen)); | |
822 | if (need % block_size != 0) | |
823 | fatal("padding error: need %d block %d mod %d", | |
824 | need, block_size, need % block_size); | |
825 | /* | |
826 | * check if the entire packet has been received and | |
827 | * decrypt into incoming_packet | |
828 | */ | |
829 | if (buffer_len(&input) < need + maclen) | |
830 | return SSH_MSG_NONE; | |
831 | #ifdef PACKET_DEBUG | |
832 | fprintf(stderr, "read_poll enc/full: "); | |
833 | buffer_dump(&input); | |
834 | #endif | |
6c0fa2b1 | 835 | cp = buffer_append_space(&incoming_packet, need); |
08dcb5d7 | 836 | cipher_decrypt(&receive_context, cp, buffer_ptr(&input), need); |
7e7327a1 | 837 | buffer_consume(&input, need); |
838 | /* | |
839 | * compute MAC over seqnr and packet, | |
840 | * increment sequence number for incoming packet | |
841 | */ | |
6ae2364d | 842 | if (mac && mac->enabled) { |
b2552997 | 843 | macbuf = mac_compute(mac, seqnr, |
20905a8e | 844 | buffer_ptr(&incoming_packet), |
b2552997 | 845 | buffer_len(&incoming_packet)); |
7e7327a1 | 846 | if (memcmp(macbuf, buffer_ptr(&input), mac->mac_len) != 0) |
94ec8c6b | 847 | packet_disconnect("Corrupted MAC on input."); |
848 | DBG(debug("MAC #%d ok", seqnr)); | |
7e7327a1 | 849 | buffer_consume(&input, mac->mac_len); |
850 | } | |
24ca6821 | 851 | if (seqnr_p != NULL) |
852 | *seqnr_p = seqnr; | |
6ae2364d | 853 | if (++seqnr == 0) |
854 | log("incoming seqnr wraps around"); | |
7e7327a1 | 855 | |
856 | /* get padlen */ | |
6c0fa2b1 | 857 | cp = buffer_ptr(&incoming_packet); |
858 | cp += 4; | |
08dcb5d7 | 859 | padlen = (u_char) *cp; |
7e7327a1 | 860 | DBG(debug("input: padlen %d", padlen)); |
861 | if (padlen < 4) | |
862 | packet_disconnect("Corrupted padlen %d on input.", padlen); | |
863 | ||
864 | /* skip packet size + padlen, discard padding */ | |
865 | buffer_consume(&incoming_packet, 4 + 1); | |
866 | buffer_consume_end(&incoming_packet, padlen); | |
867 | ||
868 | DBG(debug("input: len before de-compress %d", buffer_len(&incoming_packet))); | |
869 | if (comp && comp->enabled) { | |
870 | buffer_clear(&compression_buffer); | |
871 | buffer_uncompress(&incoming_packet, &compression_buffer); | |
872 | buffer_clear(&incoming_packet); | |
873 | buffer_append(&incoming_packet, buffer_ptr(&compression_buffer), | |
874 | buffer_len(&compression_buffer)); | |
875 | DBG(debug("input: len after de-compress %d", buffer_len(&incoming_packet))); | |
876 | } | |
877 | /* | |
878 | * get packet type, implies consume. | |
879 | * return length of payload (without type field) | |
880 | */ | |
08dcb5d7 | 881 | type = buffer_get_char(&incoming_packet); |
d1ac6175 | 882 | if (type == SSH2_MSG_NEWKEYS) |
883 | set_newkeys(MODE_IN); | |
7e7327a1 | 884 | #ifdef PACKET_DEBUG |
12bf85ed | 885 | fprintf(stderr, "read/plain[%d]:\r\n", type); |
7e7327a1 | 886 | buffer_dump(&incoming_packet); |
887 | #endif | |
08dcb5d7 | 888 | /* reset for next packet */ |
889 | packet_length = 0; | |
890 | return type; | |
7e7327a1 | 891 | } |
892 | ||
893 | int | |
54a5250f | 894 | packet_read_poll_seqnr(u_int32_t *seqnr_p) |
7e7327a1 | 895 | { |
5a5f4c37 | 896 | int reason, seqnr; |
08dcb5d7 | 897 | u_char type; |
7e7327a1 | 898 | char *msg; |
7e7327a1 | 899 | |
08dcb5d7 | 900 | for (;;) { |
901 | if (compat20) { | |
54a5250f | 902 | type = packet_read_poll2(seqnr_p); |
08dcb5d7 | 903 | if (type) |
7e7327a1 | 904 | DBG(debug("received packet type %d", type)); |
6aacefa7 | 905 | switch (type) { |
7e7327a1 | 906 | case SSH2_MSG_IGNORE: |
907 | break; | |
908 | case SSH2_MSG_DEBUG: | |
909 | packet_get_char(); | |
910 | msg = packet_get_string(NULL); | |
911 | debug("Remote: %.900s", msg); | |
912 | xfree(msg); | |
913 | msg = packet_get_string(NULL); | |
914 | xfree(msg); | |
915 | break; | |
916 | case SSH2_MSG_DISCONNECT: | |
917 | reason = packet_get_int(); | |
918 | msg = packet_get_string(NULL); | |
7c49df64 | 919 | log("Received disconnect from %s: %d: %.400s", get_remote_ipaddr(), |
920 | reason, msg); | |
7e7327a1 | 921 | xfree(msg); |
922 | fatal_cleanup(); | |
923 | break; | |
5a5f4c37 | 924 | case SSH2_MSG_UNIMPLEMENTED: |
925 | seqnr = packet_get_int(); | |
926 | debug("Received SSH2_MSG_UNIMPLEMENTED for %d", seqnr); | |
927 | break; | |
7e7327a1 | 928 | default: |
929 | return type; | |
930 | break; | |
2b87da3b | 931 | } |
7e7327a1 | 932 | } else { |
54a5250f | 933 | type = packet_read_poll1(); |
6aacefa7 | 934 | switch (type) { |
7e7327a1 | 935 | case SSH_MSG_IGNORE: |
936 | break; | |
937 | case SSH_MSG_DEBUG: | |
938 | msg = packet_get_string(NULL); | |
939 | debug("Remote: %.900s", msg); | |
940 | xfree(msg); | |
941 | break; | |
942 | case SSH_MSG_DISCONNECT: | |
943 | msg = packet_get_string(NULL); | |
7c49df64 | 944 | log("Received disconnect from %s: %.400s", get_remote_ipaddr(), |
945 | msg); | |
7e7327a1 | 946 | fatal_cleanup(); |
947 | xfree(msg); | |
948 | break; | |
949 | default: | |
08dcb5d7 | 950 | if (type) |
7e7327a1 | 951 | DBG(debug("received packet type %d", type)); |
952 | return type; | |
953 | break; | |
2b87da3b | 954 | } |
7e7327a1 | 955 | } |
956 | } | |
957 | } | |
958 | ||
24ca6821 | 959 | int |
54a5250f | 960 | packet_read_poll(void) |
24ca6821 | 961 | { |
54a5250f | 962 | return packet_read_poll_seqnr(NULL); |
24ca6821 | 963 | } |
964 | ||
aa3378df | 965 | /* |
966 | * Buffers the given amount of input characters. This is intended to be used | |
967 | * together with packet_read_poll. | |
968 | */ | |
8efc0c15 | 969 | |
970 | void | |
1e3b8b07 | 971 | packet_process_incoming(const char *buf, u_int len) |
8efc0c15 | 972 | { |
5260325f | 973 | buffer_append(&input, buf, len); |
8efc0c15 | 974 | } |
975 | ||
976 | /* Returns a character from the packet. */ | |
977 | ||
1e3b8b07 | 978 | u_int |
d5bb9418 | 979 | packet_get_char(void) |
8efc0c15 | 980 | { |
5260325f | 981 | char ch; |
982 | buffer_get(&incoming_packet, &ch, 1); | |
1e3b8b07 | 983 | return (u_char) ch; |
8efc0c15 | 984 | } |
985 | ||
986 | /* Returns an integer from the packet data. */ | |
987 | ||
1e3b8b07 | 988 | u_int |
d5bb9418 | 989 | packet_get_int(void) |
8efc0c15 | 990 | { |
5260325f | 991 | return buffer_get_int(&incoming_packet); |
8efc0c15 | 992 | } |
993 | ||
aa3378df | 994 | /* |
995 | * Returns an arbitrary precision integer from the packet data. The integer | |
996 | * must have been initialized before this call. | |
997 | */ | |
8efc0c15 | 998 | |
999 | void | |
20b279e6 | 1000 | packet_get_bignum(BIGNUM * value) |
8efc0c15 | 1001 | { |
4ef6f649 | 1002 | buffer_get_bignum(&incoming_packet, value); |
8efc0c15 | 1003 | } |
1004 | ||
7e7327a1 | 1005 | void |
20b279e6 | 1006 | packet_get_bignum2(BIGNUM * value) |
7e7327a1 | 1007 | { |
4ef6f649 | 1008 | buffer_get_bignum2(&incoming_packet, value); |
7e7327a1 | 1009 | } |
1010 | ||
6c0fa2b1 | 1011 | void * |
7e7327a1 | 1012 | packet_get_raw(int *length_ptr) |
1013 | { | |
1014 | int bytes = buffer_len(&incoming_packet); | |
1015 | if (length_ptr != NULL) | |
1016 | *length_ptr = bytes; | |
1017 | return buffer_ptr(&incoming_packet); | |
1018 | } | |
1019 | ||
6ae2364d | 1020 | int |
1021 | packet_remaining(void) | |
1022 | { | |
1023 | return buffer_len(&incoming_packet); | |
1024 | } | |
1025 | ||
aa3378df | 1026 | /* |
1027 | * Returns a string from the packet data. The string is allocated using | |
1028 | * xmalloc; it is the responsibility of the calling program to free it when | |
1029 | * no longer needed. The length_ptr argument may be NULL, or point to an | |
1030 | * integer into which the length of the string is stored. | |
1031 | */ | |
8efc0c15 | 1032 | |
6c0fa2b1 | 1033 | void * |
1e3b8b07 | 1034 | packet_get_string(u_int *length_ptr) |
8efc0c15 | 1035 | { |
5260325f | 1036 | return buffer_get_string(&incoming_packet, length_ptr); |
8efc0c15 | 1037 | } |
1038 | ||
aa3378df | 1039 | /* |
1040 | * Sends a diagnostic message from the server to the client. This message | |
1041 | * can be sent at any time (but not while constructing another message). The | |
1042 | * message is printed immediately, but only if the client is being executed | |
1043 | * in verbose mode. These messages are primarily intended to ease debugging | |
1044 | * authentication problems. The length of the formatted message must not | |
1045 | * exceed 1024 bytes. This will automatically call packet_write_wait. | |
1046 | */ | |
8efc0c15 | 1047 | |
1048 | void | |
5260325f | 1049 | packet_send_debug(const char *fmt,...) |
8efc0c15 | 1050 | { |
5260325f | 1051 | char buf[1024]; |
1052 | va_list args; | |
1053 | ||
f72fc97f | 1054 | if (compat20 && (datafellows & SSH_BUG_DEBUG)) |
1055 | return; | |
1056 | ||
5260325f | 1057 | va_start(args, fmt); |
1058 | vsnprintf(buf, sizeof(buf), fmt, args); | |
1059 | va_end(args); | |
1060 | ||
c4bc58eb | 1061 | if (compat20) { |
1062 | packet_start(SSH2_MSG_DEBUG); | |
1063 | packet_put_char(0); /* bool: always display */ | |
1064 | packet_put_cstring(buf); | |
1065 | packet_put_cstring(""); | |
1066 | } else { | |
1067 | packet_start(SSH_MSG_DEBUG); | |
1068 | packet_put_cstring(buf); | |
1069 | } | |
5260325f | 1070 | packet_send(); |
1071 | packet_write_wait(); | |
8efc0c15 | 1072 | } |
1073 | ||
aa3378df | 1074 | /* |
1075 | * Logs the error plus constructs and sends a disconnect packet, closes the | |
1076 | * connection, and exits. This function never returns. The error message | |
1077 | * should not contain a newline. The length of the formatted message must | |
1078 | * not exceed 1024 bytes. | |
1079 | */ | |
8efc0c15 | 1080 | |
1081 | void | |
5260325f | 1082 | packet_disconnect(const char *fmt,...) |
1083 | { | |
1084 | char buf[1024]; | |
1085 | va_list args; | |
1086 | static int disconnecting = 0; | |
1087 | if (disconnecting) /* Guard against recursive invocations. */ | |
1088 | fatal("packet_disconnect called recursively."); | |
1089 | disconnecting = 1; | |
1090 | ||
aa3378df | 1091 | /* |
1092 | * Format the message. Note that the caller must make sure the | |
1093 | * message is of limited size. | |
1094 | */ | |
5260325f | 1095 | va_start(args, fmt); |
1096 | vsnprintf(buf, sizeof(buf), fmt, args); | |
1097 | va_end(args); | |
1098 | ||
1099 | /* Send the disconnect message to the other side, and wait for it to get sent. */ | |
7e7327a1 | 1100 | if (compat20) { |
1101 | packet_start(SSH2_MSG_DISCONNECT); | |
1102 | packet_put_int(SSH2_DISCONNECT_PROTOCOL_ERROR); | |
1103 | packet_put_cstring(buf); | |
1104 | packet_put_cstring(""); | |
1105 | } else { | |
1106 | packet_start(SSH_MSG_DISCONNECT); | |
449c5ba5 | 1107 | packet_put_cstring(buf); |
7e7327a1 | 1108 | } |
5260325f | 1109 | packet_send(); |
1110 | packet_write_wait(); | |
1111 | ||
1112 | /* Stop listening for connections. */ | |
d6746a0b | 1113 | channel_close_all(); |
5260325f | 1114 | |
1115 | /* Close the connection. */ | |
1116 | packet_close(); | |
1117 | ||
1118 | /* Display the error locally and exit. */ | |
57112b5a | 1119 | log("Disconnecting: %.100s", buf); |
1120 | fatal_cleanup(); | |
8efc0c15 | 1121 | } |
1122 | ||
aa3378df | 1123 | /* Checks if there is any buffered output, and tries to write some of the output. */ |
8efc0c15 | 1124 | |
1125 | void | |
d5bb9418 | 1126 | packet_write_poll(void) |
8efc0c15 | 1127 | { |
5260325f | 1128 | int len = buffer_len(&output); |
1129 | if (len > 0) { | |
1130 | len = write(connection_out, buffer_ptr(&output), len); | |
1131 | if (len <= 0) { | |
1132 | if (errno == EAGAIN) | |
1133 | return; | |
1134 | else | |
1135 | fatal("Write failed: %.100s", strerror(errno)); | |
1136 | } | |
1137 | buffer_consume(&output, len); | |
1138 | } | |
8efc0c15 | 1139 | } |
1140 | ||
aa3378df | 1141 | /* |
1142 | * Calls packet_write_poll repeatedly until all pending output data has been | |
1143 | * written. | |
1144 | */ | |
8efc0c15 | 1145 | |
1146 | void | |
d5bb9418 | 1147 | packet_write_wait(void) |
8efc0c15 | 1148 | { |
20e04e90 | 1149 | fd_set *setp; |
1150 | ||
1151 | setp = (fd_set *)xmalloc(howmany(connection_out + 1, NFDBITS) * | |
1152 | sizeof(fd_mask)); | |
5260325f | 1153 | packet_write_poll(); |
1154 | while (packet_have_data_to_write()) { | |
20e04e90 | 1155 | memset(setp, 0, howmany(connection_out + 1, NFDBITS) * |
1156 | sizeof(fd_mask)); | |
1157 | FD_SET(connection_out, setp); | |
1158 | while (select(connection_out + 1, NULL, setp, NULL, NULL) == -1 && | |
fd193ca4 | 1159 | (errno == EAGAIN || errno == EINTR)) |
1160 | ; | |
5260325f | 1161 | packet_write_poll(); |
1162 | } | |
20e04e90 | 1163 | xfree(setp); |
8efc0c15 | 1164 | } |
1165 | ||
1166 | /* Returns true if there is buffered data to write to the connection. */ | |
1167 | ||
1168 | int | |
d5bb9418 | 1169 | packet_have_data_to_write(void) |
8efc0c15 | 1170 | { |
5260325f | 1171 | return buffer_len(&output) != 0; |
8efc0c15 | 1172 | } |
1173 | ||
1174 | /* Returns true if there is not too much data to write to the connection. */ | |
1175 | ||
1176 | int | |
d5bb9418 | 1177 | packet_not_very_much_data_to_write(void) |
8efc0c15 | 1178 | { |
5260325f | 1179 | if (interactive_mode) |
1180 | return buffer_len(&output) < 16384; | |
1181 | else | |
1182 | return buffer_len(&output) < 128 * 1024; | |
8efc0c15 | 1183 | } |
1184 | ||
1185 | /* Informs that the current session is interactive. Sets IP flags for that. */ | |
1186 | ||
1187 | void | |
b5c334cc | 1188 | packet_set_interactive(int interactive) |
8efc0c15 | 1189 | { |
b5c334cc | 1190 | static int called = 0; |
64e0e67e | 1191 | #if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN) |
b5c334cc | 1192 | int lowdelay = IPTOS_LOWDELAY; |
1193 | int throughput = IPTOS_THROUGHPUT; | |
64e0e67e | 1194 | #endif |
5260325f | 1195 | |
b5c334cc | 1196 | if (called) |
1197 | return; | |
1198 | called = 1; | |
1199 | ||
5260325f | 1200 | /* Record that we are in interactive mode. */ |
1201 | interactive_mode = interactive; | |
1202 | ||
48e671d5 | 1203 | /* Only set socket options if using a socket. */ |
1204 | if (!packet_connection_is_on_socket()) | |
5260325f | 1205 | return; |
48e671d5 | 1206 | /* |
f546c780 | 1207 | * IPTOS_LOWDELAY and IPTOS_THROUGHPUT are IPv4 only |
48e671d5 | 1208 | */ |
5260325f | 1209 | if (interactive) { |
aa3378df | 1210 | /* |
1211 | * Set IP options for an interactive connection. Use | |
1212 | * IPTOS_LOWDELAY and TCP_NODELAY. | |
1213 | */ | |
132dd316 | 1214 | #if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN) |
f546c780 | 1215 | if (packet_connection_is_ipv4()) { |
0e3c1f95 | 1216 | if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, |
f546c780 | 1217 | (void *) &lowdelay, sizeof(lowdelay)) < 0) |
0e3c1f95 | 1218 | error("setsockopt IPTOS_LOWDELAY: %.100s", |
f546c780 | 1219 | strerror(errno)); |
1220 | } | |
c04f75f1 | 1221 | #endif |
bcc0381e | 1222 | set_nodelay(connection_in); |
f546c780 | 1223 | } else if (packet_connection_is_ipv4()) { |
aa3378df | 1224 | /* |
1225 | * Set IP options for a non-interactive connection. Use | |
1226 | * IPTOS_THROUGHPUT. | |
1227 | */ | |
132dd316 | 1228 | #if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN) |
5260325f | 1229 | if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, (void *) &throughput, |
48e671d5 | 1230 | sizeof(throughput)) < 0) |
5260325f | 1231 | error("setsockopt IPTOS_THROUGHPUT: %.100s", strerror(errno)); |
c04f75f1 | 1232 | #endif |
5260325f | 1233 | } |
8efc0c15 | 1234 | } |
1235 | ||
1236 | /* Returns true if the current connection is interactive. */ | |
1237 | ||
1238 | int | |
d5bb9418 | 1239 | packet_is_interactive(void) |
8efc0c15 | 1240 | { |
5260325f | 1241 | return interactive_mode; |
8efc0c15 | 1242 | } |
9d6b7add | 1243 | |
1244 | int | |
1245 | packet_set_maxsize(int s) | |
1246 | { | |
5260325f | 1247 | static int called = 0; |
1248 | if (called) { | |
7e7327a1 | 1249 | log("packet_set_maxsize: called twice: old %d new %d", |
1250 | max_packet_size, s); | |
5260325f | 1251 | return -1; |
1252 | } | |
1253 | if (s < 4 * 1024 || s > 1024 * 1024) { | |
1254 | log("packet_set_maxsize: bad size %d", s); | |
1255 | return -1; | |
1256 | } | |
b6350327 | 1257 | called = 1; |
76735fe3 | 1258 | debug("packet_set_maxsize: setting to %d", s); |
5260325f | 1259 | max_packet_size = s; |
1260 | return s; | |
9d6b7add | 1261 | } |
a6215e53 | 1262 | |
b4b701be | 1263 | /* roundup current message to pad bytes */ |
1264 | void | |
1265 | packet_add_padding(u_char pad) | |
1266 | { | |
1267 | extra_pad = pad; | |
1268 | } | |
1269 | ||
a6215e53 | 1270 | /* |
1271 | * 9.2. Ignored Data Message | |
cd332296 | 1272 | * |
a6215e53 | 1273 | * byte SSH_MSG_IGNORE |
1274 | * string data | |
cd332296 | 1275 | * |
a6215e53 | 1276 | * All implementations MUST understand (and ignore) this message at any |
1277 | * time (after receiving the protocol version). No implementation is | |
1278 | * required to send them. This message can be used as an additional | |
1279 | * protection measure against advanced traffic analysis techniques. | |
1280 | */ | |
95ce5599 | 1281 | void |
1282 | packet_send_ignore(int nbytes) | |
1283 | { | |
1284 | u_int32_t rand = 0; | |
1285 | int i; | |
1286 | ||
1287 | packet_start(compat20 ? SSH2_MSG_IGNORE : SSH_MSG_IGNORE); | |
a6215e53 | 1288 | packet_put_int(nbytes); |
184eed6a | 1289 | for (i = 0; i < nbytes; i++) { |
a6215e53 | 1290 | if (i % 4 == 0) |
1291 | rand = arc4random(); | |
1292 | packet_put_char(rand & 0xff); | |
1293 | rand >>= 8; | |
1294 | } | |
1295 | } |