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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" | |
6c0fa2b1 | 40 | RCSID("$OpenBSD: packet.c,v 1.76 2001/12/19 17:16:13 stevesk Exp $"); |
8efc0c15 | 41 | |
42 | #include "xmalloc.h" | |
43 | #include "buffer.h" | |
44 | #include "packet.h" | |
45 | #include "bufaux.h" | |
8efc0c15 | 46 | #include "crc32.h" |
8efc0c15 | 47 | #include "getput.h" |
48 | ||
49 | #include "compress.h" | |
50 | #include "deattack.h" | |
a5efa1bb | 51 | #include "channels.h" |
8efc0c15 | 52 | |
7e7327a1 | 53 | #include "compat.h" |
42f11eb2 | 54 | #include "ssh1.h" |
7e7327a1 | 55 | #include "ssh2.h" |
56 | ||
94ec8c6b | 57 | #include "cipher.h" |
7e7327a1 | 58 | #include "kex.h" |
b2552997 | 59 | #include "mac.h" |
42f11eb2 | 60 | #include "log.h" |
61 | #include "canohost.h" | |
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; | |
1e3b8b07 | 133 | cipher_init(&send_context, none, (u_char *) "", 0, NULL, 0); |
134 | cipher_init(&receive_context, none, (u_char *) "", 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. */ | |
1e3b8b07 | 402 | checksum = ssh_crc32((u_char *) 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 | |
08dcb5d7 | 508 | ucp = (u_char *) buffer_ptr(&outgoing_packet); |
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; | |
08dcb5d7 | 564 | ucp = (u_char *)buffer_ptr(&outgoing_packet); |
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, |
1e3b8b07 | 572 | (u_char *) 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 | |
613 | packet_read(int *payload_len_ptr) | |
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. */ | |
629 | type = packet_read_poll(payload_len_ptr); | |
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)) |
5260325f | 635 | packet_integrity_check(*payload_len_ptr, 0, type); |
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 | ||
aa3378df | 668 | /* |
669 | * Waits until a packet has been received, verifies that its type matches | |
670 | * that given, and gives a fatal error and exits if there is a mismatch. | |
671 | */ | |
8efc0c15 | 672 | |
673 | void | |
674 | packet_read_expect(int *payload_len_ptr, int expected_type) | |
675 | { | |
5260325f | 676 | int type; |
8efc0c15 | 677 | |
5260325f | 678 | type = packet_read(payload_len_ptr); |
679 | if (type != expected_type) | |
680 | packet_disconnect("Protocol error: expected packet type %d, got %d", | |
7e7327a1 | 681 | expected_type, type); |
8efc0c15 | 682 | } |
683 | ||
684 | /* Checks if a full packet is available in the data received so far via | |
5260325f | 685 | * packet_process_incoming. If so, reads the packet; otherwise returns |
686 | * SSH_MSG_NONE. This does not wait for data from the connection. | |
687 | * | |
688 | * SSH_MSG_DISCONNECT is handled specially here. Also, | |
689 | * SSH_MSG_IGNORE messages are skipped by this function and are never returned | |
690 | * to higher levels. | |
691 | * | |
692 | * The returned payload_len does include space consumed by: | |
693 | * Packet length | |
694 | * Padding | |
695 | * Packet type | |
696 | * Check bytes | |
697 | */ | |
8efc0c15 | 698 | |
396c147e | 699 | static int |
7e7327a1 | 700 | packet_read_poll1(int *payload_len_ptr) |
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. */ | |
1e3b8b07 | 711 | ucp = (u_char *) 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. */ | |
1e3b8b07 | 748 | checksum = ssh_crc32((u_char *) 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)) |
756 | packet_disconnect("packet_read_poll: len %d != buffer_len %d.", | |
7e7327a1 | 757 | len, buffer_len(&incoming_packet)); |
5260325f | 758 | |
1e3b8b07 | 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); |
5260325f | 773 | *payload_len_ptr = buffer_len(&incoming_packet); |
08dcb5d7 | 774 | return type; |
5260325f | 775 | } |
776 | ||
396c147e | 777 | static int |
7e7327a1 | 778 | packet_read_poll2(int *payload_len_ptr) |
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); |
1e3b8b07 | 809 | ucp = (u_char *) 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, |
1e3b8b07 | 844 | (u_char *) 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 | } | |
6ae2364d | 851 | if (++seqnr == 0) |
852 | log("incoming seqnr wraps around"); | |
7e7327a1 | 853 | |
854 | /* get padlen */ | |
6c0fa2b1 | 855 | cp = buffer_ptr(&incoming_packet); |
856 | cp += 4; | |
08dcb5d7 | 857 | padlen = (u_char) *cp; |
7e7327a1 | 858 | DBG(debug("input: padlen %d", padlen)); |
859 | if (padlen < 4) | |
860 | packet_disconnect("Corrupted padlen %d on input.", padlen); | |
861 | ||
862 | /* skip packet size + padlen, discard padding */ | |
863 | buffer_consume(&incoming_packet, 4 + 1); | |
864 | buffer_consume_end(&incoming_packet, padlen); | |
865 | ||
866 | DBG(debug("input: len before de-compress %d", buffer_len(&incoming_packet))); | |
867 | if (comp && comp->enabled) { | |
868 | buffer_clear(&compression_buffer); | |
869 | buffer_uncompress(&incoming_packet, &compression_buffer); | |
870 | buffer_clear(&incoming_packet); | |
871 | buffer_append(&incoming_packet, buffer_ptr(&compression_buffer), | |
872 | buffer_len(&compression_buffer)); | |
873 | DBG(debug("input: len after de-compress %d", buffer_len(&incoming_packet))); | |
874 | } | |
875 | /* | |
876 | * get packet type, implies consume. | |
877 | * return length of payload (without type field) | |
878 | */ | |
08dcb5d7 | 879 | type = buffer_get_char(&incoming_packet); |
d1ac6175 | 880 | if (type == SSH2_MSG_NEWKEYS) |
881 | set_newkeys(MODE_IN); | |
08dcb5d7 | 882 | *payload_len_ptr = buffer_len(&incoming_packet); |
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 | |
893 | packet_read_poll(int *payload_len_ptr) | |
894 | { | |
08dcb5d7 | 895 | int reason; |
896 | u_char type; | |
7e7327a1 | 897 | char *msg; |
7e7327a1 | 898 | |
08dcb5d7 | 899 | for (;;) { |
900 | if (compat20) { | |
901 | type = packet_read_poll2(payload_len_ptr); | |
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; | |
923 | default: | |
924 | return type; | |
925 | break; | |
2b87da3b | 926 | } |
7e7327a1 | 927 | } else { |
08dcb5d7 | 928 | type = packet_read_poll1(payload_len_ptr); |
6aacefa7 | 929 | switch (type) { |
7e7327a1 | 930 | case SSH_MSG_IGNORE: |
931 | break; | |
932 | case SSH_MSG_DEBUG: | |
933 | msg = packet_get_string(NULL); | |
934 | debug("Remote: %.900s", msg); | |
935 | xfree(msg); | |
936 | break; | |
937 | case SSH_MSG_DISCONNECT: | |
938 | msg = packet_get_string(NULL); | |
7c49df64 | 939 | log("Received disconnect from %s: %.400s", get_remote_ipaddr(), |
940 | msg); | |
7e7327a1 | 941 | fatal_cleanup(); |
942 | xfree(msg); | |
943 | break; | |
944 | default: | |
08dcb5d7 | 945 | if (type) |
7e7327a1 | 946 | DBG(debug("received packet type %d", type)); |
947 | return type; | |
948 | break; | |
2b87da3b | 949 | } |
7e7327a1 | 950 | } |
951 | } | |
952 | } | |
953 | ||
aa3378df | 954 | /* |
955 | * Buffers the given amount of input characters. This is intended to be used | |
956 | * together with packet_read_poll. | |
957 | */ | |
8efc0c15 | 958 | |
959 | void | |
1e3b8b07 | 960 | packet_process_incoming(const char *buf, u_int len) |
8efc0c15 | 961 | { |
5260325f | 962 | buffer_append(&input, buf, len); |
8efc0c15 | 963 | } |
964 | ||
965 | /* Returns a character from the packet. */ | |
966 | ||
1e3b8b07 | 967 | u_int |
d5bb9418 | 968 | packet_get_char(void) |
8efc0c15 | 969 | { |
5260325f | 970 | char ch; |
971 | buffer_get(&incoming_packet, &ch, 1); | |
1e3b8b07 | 972 | return (u_char) ch; |
8efc0c15 | 973 | } |
974 | ||
975 | /* Returns an integer from the packet data. */ | |
976 | ||
1e3b8b07 | 977 | u_int |
d5bb9418 | 978 | packet_get_int(void) |
8efc0c15 | 979 | { |
5260325f | 980 | return buffer_get_int(&incoming_packet); |
8efc0c15 | 981 | } |
982 | ||
aa3378df | 983 | /* |
984 | * Returns an arbitrary precision integer from the packet data. The integer | |
985 | * must have been initialized before this call. | |
986 | */ | |
8efc0c15 | 987 | |
988 | void | |
5260325f | 989 | packet_get_bignum(BIGNUM * value, int *length_ptr) |
8efc0c15 | 990 | { |
5260325f | 991 | *length_ptr = buffer_get_bignum(&incoming_packet, value); |
8efc0c15 | 992 | } |
993 | ||
7e7327a1 | 994 | void |
995 | packet_get_bignum2(BIGNUM * value, int *length_ptr) | |
996 | { | |
997 | *length_ptr = buffer_get_bignum2(&incoming_packet, value); | |
998 | } | |
999 | ||
6c0fa2b1 | 1000 | void * |
7e7327a1 | 1001 | packet_get_raw(int *length_ptr) |
1002 | { | |
1003 | int bytes = buffer_len(&incoming_packet); | |
1004 | if (length_ptr != NULL) | |
1005 | *length_ptr = bytes; | |
1006 | return buffer_ptr(&incoming_packet); | |
1007 | } | |
1008 | ||
6ae2364d | 1009 | int |
1010 | packet_remaining(void) | |
1011 | { | |
1012 | return buffer_len(&incoming_packet); | |
1013 | } | |
1014 | ||
aa3378df | 1015 | /* |
1016 | * Returns a string from the packet data. The string is allocated using | |
1017 | * xmalloc; it is the responsibility of the calling program to free it when | |
1018 | * no longer needed. The length_ptr argument may be NULL, or point to an | |
1019 | * integer into which the length of the string is stored. | |
1020 | */ | |
8efc0c15 | 1021 | |
6c0fa2b1 | 1022 | void * |
1e3b8b07 | 1023 | packet_get_string(u_int *length_ptr) |
8efc0c15 | 1024 | { |
5260325f | 1025 | return buffer_get_string(&incoming_packet, length_ptr); |
8efc0c15 | 1026 | } |
1027 | ||
aa3378df | 1028 | /* |
1029 | * Sends a diagnostic message from the server to the client. This message | |
1030 | * can be sent at any time (but not while constructing another message). The | |
1031 | * message is printed immediately, but only if the client is being executed | |
1032 | * in verbose mode. These messages are primarily intended to ease debugging | |
1033 | * authentication problems. The length of the formatted message must not | |
1034 | * exceed 1024 bytes. This will automatically call packet_write_wait. | |
1035 | */ | |
8efc0c15 | 1036 | |
1037 | void | |
5260325f | 1038 | packet_send_debug(const char *fmt,...) |
8efc0c15 | 1039 | { |
5260325f | 1040 | char buf[1024]; |
1041 | va_list args; | |
1042 | ||
f72fc97f | 1043 | if (compat20 && (datafellows & SSH_BUG_DEBUG)) |
1044 | return; | |
1045 | ||
5260325f | 1046 | va_start(args, fmt); |
1047 | vsnprintf(buf, sizeof(buf), fmt, args); | |
1048 | va_end(args); | |
1049 | ||
c4bc58eb | 1050 | if (compat20) { |
1051 | packet_start(SSH2_MSG_DEBUG); | |
1052 | packet_put_char(0); /* bool: always display */ | |
1053 | packet_put_cstring(buf); | |
1054 | packet_put_cstring(""); | |
1055 | } else { | |
1056 | packet_start(SSH_MSG_DEBUG); | |
1057 | packet_put_cstring(buf); | |
1058 | } | |
5260325f | 1059 | packet_send(); |
1060 | packet_write_wait(); | |
8efc0c15 | 1061 | } |
1062 | ||
aa3378df | 1063 | /* |
1064 | * Logs the error plus constructs and sends a disconnect packet, closes the | |
1065 | * connection, and exits. This function never returns. The error message | |
1066 | * should not contain a newline. The length of the formatted message must | |
1067 | * not exceed 1024 bytes. | |
1068 | */ | |
8efc0c15 | 1069 | |
1070 | void | |
5260325f | 1071 | packet_disconnect(const char *fmt,...) |
1072 | { | |
1073 | char buf[1024]; | |
1074 | va_list args; | |
1075 | static int disconnecting = 0; | |
1076 | if (disconnecting) /* Guard against recursive invocations. */ | |
1077 | fatal("packet_disconnect called recursively."); | |
1078 | disconnecting = 1; | |
1079 | ||
aa3378df | 1080 | /* |
1081 | * Format the message. Note that the caller must make sure the | |
1082 | * message is of limited size. | |
1083 | */ | |
5260325f | 1084 | va_start(args, fmt); |
1085 | vsnprintf(buf, sizeof(buf), fmt, args); | |
1086 | va_end(args); | |
1087 | ||
1088 | /* Send the disconnect message to the other side, and wait for it to get sent. */ | |
7e7327a1 | 1089 | if (compat20) { |
1090 | packet_start(SSH2_MSG_DISCONNECT); | |
1091 | packet_put_int(SSH2_DISCONNECT_PROTOCOL_ERROR); | |
1092 | packet_put_cstring(buf); | |
1093 | packet_put_cstring(""); | |
1094 | } else { | |
1095 | packet_start(SSH_MSG_DISCONNECT); | |
449c5ba5 | 1096 | packet_put_cstring(buf); |
7e7327a1 | 1097 | } |
5260325f | 1098 | packet_send(); |
1099 | packet_write_wait(); | |
1100 | ||
1101 | /* Stop listening for connections. */ | |
d6746a0b | 1102 | channel_close_all(); |
5260325f | 1103 | |
1104 | /* Close the connection. */ | |
1105 | packet_close(); | |
1106 | ||
1107 | /* Display the error locally and exit. */ | |
57112b5a | 1108 | log("Disconnecting: %.100s", buf); |
1109 | fatal_cleanup(); | |
8efc0c15 | 1110 | } |
1111 | ||
aa3378df | 1112 | /* Checks if there is any buffered output, and tries to write some of the output. */ |
8efc0c15 | 1113 | |
1114 | void | |
d5bb9418 | 1115 | packet_write_poll(void) |
8efc0c15 | 1116 | { |
5260325f | 1117 | int len = buffer_len(&output); |
1118 | if (len > 0) { | |
1119 | len = write(connection_out, buffer_ptr(&output), len); | |
1120 | if (len <= 0) { | |
1121 | if (errno == EAGAIN) | |
1122 | return; | |
1123 | else | |
1124 | fatal("Write failed: %.100s", strerror(errno)); | |
1125 | } | |
1126 | buffer_consume(&output, len); | |
1127 | } | |
8efc0c15 | 1128 | } |
1129 | ||
aa3378df | 1130 | /* |
1131 | * Calls packet_write_poll repeatedly until all pending output data has been | |
1132 | * written. | |
1133 | */ | |
8efc0c15 | 1134 | |
1135 | void | |
d5bb9418 | 1136 | packet_write_wait(void) |
8efc0c15 | 1137 | { |
20e04e90 | 1138 | fd_set *setp; |
1139 | ||
1140 | setp = (fd_set *)xmalloc(howmany(connection_out + 1, NFDBITS) * | |
1141 | sizeof(fd_mask)); | |
5260325f | 1142 | packet_write_poll(); |
1143 | while (packet_have_data_to_write()) { | |
20e04e90 | 1144 | memset(setp, 0, howmany(connection_out + 1, NFDBITS) * |
1145 | sizeof(fd_mask)); | |
1146 | FD_SET(connection_out, setp); | |
1147 | while (select(connection_out + 1, NULL, setp, NULL, NULL) == -1 && | |
fd193ca4 | 1148 | (errno == EAGAIN || errno == EINTR)) |
1149 | ; | |
5260325f | 1150 | packet_write_poll(); |
1151 | } | |
20e04e90 | 1152 | xfree(setp); |
8efc0c15 | 1153 | } |
1154 | ||
1155 | /* Returns true if there is buffered data to write to the connection. */ | |
1156 | ||
1157 | int | |
d5bb9418 | 1158 | packet_have_data_to_write(void) |
8efc0c15 | 1159 | { |
5260325f | 1160 | return buffer_len(&output) != 0; |
8efc0c15 | 1161 | } |
1162 | ||
1163 | /* Returns true if there is not too much data to write to the connection. */ | |
1164 | ||
1165 | int | |
d5bb9418 | 1166 | packet_not_very_much_data_to_write(void) |
8efc0c15 | 1167 | { |
5260325f | 1168 | if (interactive_mode) |
1169 | return buffer_len(&output) < 16384; | |
1170 | else | |
1171 | return buffer_len(&output) < 128 * 1024; | |
8efc0c15 | 1172 | } |
1173 | ||
1174 | /* Informs that the current session is interactive. Sets IP flags for that. */ | |
1175 | ||
1176 | void | |
b5c334cc | 1177 | packet_set_interactive(int interactive) |
8efc0c15 | 1178 | { |
b5c334cc | 1179 | static int called = 0; |
64e0e67e | 1180 | #if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN) |
b5c334cc | 1181 | int lowdelay = IPTOS_LOWDELAY; |
1182 | int throughput = IPTOS_THROUGHPUT; | |
64e0e67e | 1183 | #endif |
5260325f | 1184 | int on = 1; |
1185 | ||
b5c334cc | 1186 | if (called) |
1187 | return; | |
1188 | called = 1; | |
1189 | ||
5260325f | 1190 | /* Record that we are in interactive mode. */ |
1191 | interactive_mode = interactive; | |
1192 | ||
48e671d5 | 1193 | /* Only set socket options if using a socket. */ |
1194 | if (!packet_connection_is_on_socket()) | |
5260325f | 1195 | return; |
48e671d5 | 1196 | /* |
f546c780 | 1197 | * IPTOS_LOWDELAY and IPTOS_THROUGHPUT are IPv4 only |
48e671d5 | 1198 | */ |
5260325f | 1199 | if (interactive) { |
aa3378df | 1200 | /* |
1201 | * Set IP options for an interactive connection. Use | |
1202 | * IPTOS_LOWDELAY and TCP_NODELAY. | |
1203 | */ | |
132dd316 | 1204 | #if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN) |
f546c780 | 1205 | if (packet_connection_is_ipv4()) { |
0e3c1f95 | 1206 | if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, |
f546c780 | 1207 | (void *) &lowdelay, sizeof(lowdelay)) < 0) |
0e3c1f95 | 1208 | error("setsockopt IPTOS_LOWDELAY: %.100s", |
f546c780 | 1209 | strerror(errno)); |
1210 | } | |
c04f75f1 | 1211 | #endif |
5260325f | 1212 | if (setsockopt(connection_in, IPPROTO_TCP, TCP_NODELAY, (void *) &on, |
48e671d5 | 1213 | sizeof(on)) < 0) |
5260325f | 1214 | error("setsockopt TCP_NODELAY: %.100s", strerror(errno)); |
f546c780 | 1215 | } else if (packet_connection_is_ipv4()) { |
aa3378df | 1216 | /* |
1217 | * Set IP options for a non-interactive connection. Use | |
1218 | * IPTOS_THROUGHPUT. | |
1219 | */ | |
132dd316 | 1220 | #if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN) |
5260325f | 1221 | if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, (void *) &throughput, |
48e671d5 | 1222 | sizeof(throughput)) < 0) |
5260325f | 1223 | error("setsockopt IPTOS_THROUGHPUT: %.100s", strerror(errno)); |
c04f75f1 | 1224 | #endif |
5260325f | 1225 | } |
8efc0c15 | 1226 | } |
1227 | ||
1228 | /* Returns true if the current connection is interactive. */ | |
1229 | ||
1230 | int | |
d5bb9418 | 1231 | packet_is_interactive(void) |
8efc0c15 | 1232 | { |
5260325f | 1233 | return interactive_mode; |
8efc0c15 | 1234 | } |
9d6b7add | 1235 | |
1236 | int | |
1237 | packet_set_maxsize(int s) | |
1238 | { | |
5260325f | 1239 | static int called = 0; |
1240 | if (called) { | |
7e7327a1 | 1241 | log("packet_set_maxsize: called twice: old %d new %d", |
1242 | max_packet_size, s); | |
5260325f | 1243 | return -1; |
1244 | } | |
1245 | if (s < 4 * 1024 || s > 1024 * 1024) { | |
1246 | log("packet_set_maxsize: bad size %d", s); | |
1247 | return -1; | |
1248 | } | |
b6350327 | 1249 | called = 1; |
76735fe3 | 1250 | debug("packet_set_maxsize: setting to %d", s); |
5260325f | 1251 | max_packet_size = s; |
1252 | return s; | |
9d6b7add | 1253 | } |
a6215e53 | 1254 | |
b4b701be | 1255 | /* roundup current message to pad bytes */ |
1256 | void | |
1257 | packet_add_padding(u_char pad) | |
1258 | { | |
1259 | extra_pad = pad; | |
1260 | } | |
1261 | ||
a6215e53 | 1262 | /* |
1263 | * 9.2. Ignored Data Message | |
cd332296 | 1264 | * |
a6215e53 | 1265 | * byte SSH_MSG_IGNORE |
1266 | * string data | |
cd332296 | 1267 | * |
a6215e53 | 1268 | * All implementations MUST understand (and ignore) this message at any |
1269 | * time (after receiving the protocol version). No implementation is | |
1270 | * required to send them. This message can be used as an additional | |
1271 | * protection measure against advanced traffic analysis techniques. | |
1272 | */ | |
95ce5599 | 1273 | void |
1274 | packet_send_ignore(int nbytes) | |
1275 | { | |
1276 | u_int32_t rand = 0; | |
1277 | int i; | |
1278 | ||
1279 | packet_start(compat20 ? SSH2_MSG_IGNORE : SSH_MSG_IGNORE); | |
a6215e53 | 1280 | packet_put_int(nbytes); |
184eed6a | 1281 | for (i = 0; i < nbytes; i++) { |
a6215e53 | 1282 | if (i % 4 == 0) |
1283 | rand = arc4random(); | |
1284 | packet_put_char(rand & 0xff); | |
1285 | rand >>= 8; | |
1286 | } | |
1287 | } |