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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. |
bcbf86ec | 16 | * Copyright (c) 2000 Markus Friedl. All rights reserved. |
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" | |
7c49df64 | 40 | RCSID("$OpenBSD: packet.c,v 1.41 2001/01/02 20:41:02 markus Exp $"); |
8efc0c15 | 41 | |
42 | #include "xmalloc.h" | |
43 | #include "buffer.h" | |
44 | #include "packet.h" | |
45 | #include "bufaux.h" | |
46 | #include "ssh.h" | |
47 | #include "crc32.h" | |
8efc0c15 | 48 | #include "getput.h" |
49 | ||
50 | #include "compress.h" | |
51 | #include "deattack.h" | |
7368a6c8 | 52 | #include "channels.h" |
8efc0c15 | 53 | |
7e7327a1 | 54 | #include "compat.h" |
55 | #include "ssh2.h" | |
56 | ||
35484284 | 57 | #include <openssl/bn.h> |
58 | #include <openssl/dh.h> | |
59 | #include <openssl/hmac.h> | |
7e7327a1 | 60 | #include "buffer.h" |
94ec8c6b | 61 | #include "cipher.h" |
7e7327a1 | 62 | #include "kex.h" |
63 | #include "hmac.h" | |
64 | ||
65 | #ifdef PACKET_DEBUG | |
66 | #define DBG(x) x | |
67 | #else | |
68 | #define DBG(x) | |
69 | #endif | |
70 | ||
aa3378df | 71 | /* |
72 | * This variable contains the file descriptors used for communicating with | |
73 | * the other side. connection_in is used for reading; connection_out for | |
74 | * writing. These can be the same descriptor, in which case it is assumed to | |
75 | * be a socket. | |
76 | */ | |
8efc0c15 | 77 | static int connection_in = -1; |
78 | static int connection_out = -1; | |
79 | ||
aa3378df | 80 | /* |
81 | * Cipher type. This value is only used to determine whether to pad the | |
82 | * packets with zeroes or random data. | |
83 | */ | |
8efc0c15 | 84 | static int cipher_type = SSH_CIPHER_NONE; |
85 | ||
86 | /* Protocol flags for the remote side. */ | |
1e3b8b07 | 87 | static u_int remote_protocol_flags = 0; |
8efc0c15 | 88 | |
89 | /* Encryption context for receiving data. This is only used for decryption. */ | |
90 | static CipherContext receive_context; | |
5260325f | 91 | |
92 | /* Encryption context for sending data. This is only used for encryption. */ | |
8efc0c15 | 93 | static CipherContext send_context; |
94 | ||
95 | /* Buffer for raw input data from the socket. */ | |
96 | static Buffer input; | |
97 | ||
98 | /* Buffer for raw output data going to the socket. */ | |
99 | static Buffer output; | |
100 | ||
101 | /* Buffer for the partial outgoing packet being constructed. */ | |
102 | static Buffer outgoing_packet; | |
103 | ||
104 | /* Buffer for the incoming packet currently being processed. */ | |
105 | static Buffer incoming_packet; | |
106 | ||
107 | /* Scratch buffer for packet compression/decompression. */ | |
108 | static Buffer compression_buffer; | |
109 | ||
110 | /* Flag indicating whether packet compression/decompression is enabled. */ | |
111 | static int packet_compression = 0; | |
112 | ||
9d6b7add | 113 | /* default maximum packet size */ |
114 | int max_packet_size = 32768; | |
115 | ||
8efc0c15 | 116 | /* Flag indicating whether this module has been initialized. */ |
117 | static int initialized = 0; | |
118 | ||
119 | /* Set to true if the connection is interactive. */ | |
120 | static int interactive_mode = 0; | |
121 | ||
7e7327a1 | 122 | /* True if SSH2 packet format is used */ |
123 | int use_ssh2_packet_format = 0; | |
124 | ||
125 | /* Session key information for Encryption and MAC */ | |
126 | Kex *kex = NULL; | |
127 | ||
128 | void | |
129 | packet_set_kex(Kex *k) | |
130 | { | |
131 | if( k->mac[MODE_IN ].key == NULL || | |
132 | k->enc[MODE_IN ].key == NULL || | |
133 | k->enc[MODE_IN ].iv == NULL || | |
134 | k->mac[MODE_OUT].key == NULL || | |
135 | k->enc[MODE_OUT].key == NULL || | |
136 | k->enc[MODE_OUT].iv == NULL) | |
137 | fatal("bad KEX"); | |
138 | kex = k; | |
139 | } | |
140 | void | |
141 | clear_enc_keys(Enc *enc, int len) | |
142 | { | |
143 | memset(enc->iv, 0, len); | |
144 | memset(enc->key, 0, len); | |
145 | xfree(enc->iv); | |
146 | xfree(enc->key); | |
147 | enc->iv = NULL; | |
148 | enc->key = NULL; | |
149 | } | |
150 | void | |
151 | packet_set_ssh2_format(void) | |
152 | { | |
3189621b | 153 | DBG(debug("use_ssh2_packet_format")); |
7e7327a1 | 154 | use_ssh2_packet_format = 1; |
155 | } | |
156 | ||
aa3378df | 157 | /* |
158 | * Sets the descriptors used for communication. Disables encryption until | |
159 | * packet_set_encryption_key is called. | |
160 | */ | |
8efc0c15 | 161 | void |
162 | packet_set_connection(int fd_in, int fd_out) | |
163 | { | |
94ec8c6b | 164 | Cipher *none = cipher_by_name("none"); |
165 | if (none == NULL) | |
166 | fatal("packet_set_connection: cannot load cipher 'none'"); | |
5260325f | 167 | connection_in = fd_in; |
168 | connection_out = fd_out; | |
169 | cipher_type = SSH_CIPHER_NONE; | |
1e3b8b07 | 170 | cipher_init(&send_context, none, (u_char *) "", 0, NULL, 0); |
171 | cipher_init(&receive_context, none, (u_char *) "", 0, NULL, 0); | |
5260325f | 172 | if (!initialized) { |
173 | initialized = 1; | |
174 | buffer_init(&input); | |
175 | buffer_init(&output); | |
176 | buffer_init(&outgoing_packet); | |
177 | buffer_init(&incoming_packet); | |
178 | } | |
179 | /* Kludge: arrange the close function to be called from fatal(). */ | |
180 | fatal_add_cleanup((void (*) (void *)) packet_close, NULL); | |
8efc0c15 | 181 | } |
182 | ||
48e671d5 | 183 | /* Returns 1 if remote host is connected via socket, 0 if not. */ |
184 | ||
185 | int | |
186 | packet_connection_is_on_socket() | |
187 | { | |
188 | struct sockaddr_storage from, to; | |
189 | socklen_t fromlen, tolen; | |
190 | ||
191 | /* filedescriptors in and out are the same, so it's a socket */ | |
192 | if (connection_in == connection_out) | |
193 | return 1; | |
194 | fromlen = sizeof(from); | |
195 | memset(&from, 0, sizeof(from)); | |
9bc5ddfe | 196 | if (getpeername(connection_in, (struct sockaddr *)&from, &fromlen) < 0) |
48e671d5 | 197 | return 0; |
198 | tolen = sizeof(to); | |
199 | memset(&to, 0, sizeof(to)); | |
9bc5ddfe | 200 | if (getpeername(connection_out, (struct sockaddr *)&to, &tolen) < 0) |
48e671d5 | 201 | return 0; |
202 | if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0) | |
203 | return 0; | |
204 | if (from.ss_family != AF_INET && from.ss_family != AF_INET6) | |
205 | return 0; | |
206 | return 1; | |
207 | } | |
208 | ||
209 | /* returns 1 if connection is via ipv4 */ | |
210 | ||
211 | int | |
212 | packet_connection_is_ipv4() | |
213 | { | |
214 | struct sockaddr_storage to; | |
d45317d8 | 215 | socklen_t tolen = sizeof(to); |
48e671d5 | 216 | |
217 | memset(&to, 0, sizeof(to)); | |
218 | if (getsockname(connection_out, (struct sockaddr *)&to, &tolen) < 0) | |
219 | return 0; | |
220 | if (to.ss_family != AF_INET) | |
221 | return 0; | |
222 | return 1; | |
223 | } | |
224 | ||
8efc0c15 | 225 | /* Sets the connection into non-blocking mode. */ |
226 | ||
227 | void | |
228 | packet_set_nonblocking() | |
229 | { | |
5260325f | 230 | /* Set the socket into non-blocking mode. */ |
231 | if (fcntl(connection_in, F_SETFL, O_NONBLOCK) < 0) | |
232 | error("fcntl O_NONBLOCK: %.100s", strerror(errno)); | |
8efc0c15 | 233 | |
5260325f | 234 | if (connection_out != connection_in) { |
235 | if (fcntl(connection_out, F_SETFL, O_NONBLOCK) < 0) | |
236 | error("fcntl O_NONBLOCK: %.100s", strerror(errno)); | |
237 | } | |
8efc0c15 | 238 | } |
239 | ||
240 | /* Returns the socket used for reading. */ | |
241 | ||
242 | int | |
243 | packet_get_connection_in() | |
244 | { | |
5260325f | 245 | return connection_in; |
8efc0c15 | 246 | } |
247 | ||
248 | /* Returns the descriptor used for writing. */ | |
249 | ||
250 | int | |
251 | packet_get_connection_out() | |
252 | { | |
5260325f | 253 | return connection_out; |
8efc0c15 | 254 | } |
255 | ||
256 | /* Closes the connection and clears and frees internal data structures. */ | |
257 | ||
258 | void | |
259 | packet_close() | |
260 | { | |
5260325f | 261 | if (!initialized) |
262 | return; | |
263 | initialized = 0; | |
264 | if (connection_in == connection_out) { | |
265 | shutdown(connection_out, SHUT_RDWR); | |
266 | close(connection_out); | |
267 | } else { | |
268 | close(connection_in); | |
269 | close(connection_out); | |
270 | } | |
271 | buffer_free(&input); | |
272 | buffer_free(&output); | |
273 | buffer_free(&outgoing_packet); | |
274 | buffer_free(&incoming_packet); | |
275 | if (packet_compression) { | |
276 | buffer_free(&compression_buffer); | |
277 | buffer_compress_uninit(); | |
278 | } | |
8efc0c15 | 279 | } |
280 | ||
281 | /* Sets remote side protocol flags. */ | |
282 | ||
283 | void | |
1e3b8b07 | 284 | packet_set_protocol_flags(u_int protocol_flags) |
8efc0c15 | 285 | { |
5260325f | 286 | remote_protocol_flags = protocol_flags; |
287 | channel_set_options((protocol_flags & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) != 0); | |
8efc0c15 | 288 | } |
289 | ||
290 | /* Returns the remote protocol flags set earlier by the above function. */ | |
291 | ||
1e3b8b07 | 292 | u_int |
8efc0c15 | 293 | packet_get_protocol_flags() |
294 | { | |
5260325f | 295 | return remote_protocol_flags; |
8efc0c15 | 296 | } |
297 | ||
aa3378df | 298 | /* |
299 | * Starts packet compression from the next packet on in both directions. | |
300 | * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip. | |
301 | */ | |
8efc0c15 | 302 | |
7e7327a1 | 303 | /*** XXXXX todo: kex means re-init */ |
8efc0c15 | 304 | void |
305 | packet_start_compression(int level) | |
306 | { | |
5260325f | 307 | if (packet_compression) |
308 | fatal("Compression already enabled."); | |
309 | packet_compression = 1; | |
310 | buffer_init(&compression_buffer); | |
311 | buffer_compress_init(level); | |
8efc0c15 | 312 | } |
313 | ||
aa3378df | 314 | /* |
315 | * Encrypts the given number of bytes, copying from src to dest. bytes is | |
316 | * known to be a multiple of 8. | |
317 | */ | |
8efc0c15 | 318 | |
319 | void | |
5260325f | 320 | packet_encrypt(CipherContext * cc, void *dest, void *src, |
1e3b8b07 | 321 | u_int bytes) |
8efc0c15 | 322 | { |
5260325f | 323 | cipher_encrypt(cc, dest, src, bytes); |
8efc0c15 | 324 | } |
325 | ||
aa3378df | 326 | /* |
327 | * Decrypts the given number of bytes, copying from src to dest. bytes is | |
328 | * known to be a multiple of 8. | |
329 | */ | |
8efc0c15 | 330 | |
331 | void | |
1e3b8b07 | 332 | packet_decrypt(CipherContext *context, void *dest, void *src, u_int bytes) |
8efc0c15 | 333 | { |
aa3378df | 334 | /* |
335 | * Cryptographic attack detector for ssh - Modifications for packet.c | |
336 | * (C)1998 CORE-SDI, Buenos Aires Argentina Ariel Futoransky(futo@core-sdi.com) | |
337 | */ | |
94ec8c6b | 338 | if (!compat20 && |
339 | context->cipher->number != SSH_CIPHER_NONE && | |
340 | detect_attack(src, bytes, NULL) == DEATTACK_DETECTED) | |
5260325f | 341 | packet_disconnect("crc32 compensation attack: network attack detected"); |
342 | ||
94ec8c6b | 343 | cipher_decrypt(context, dest, src, bytes); |
8efc0c15 | 344 | } |
345 | ||
aa3378df | 346 | /* |
347 | * Causes any further packets to be encrypted using the given key. The same | |
348 | * key is used for both sending and reception. However, both directions are | |
349 | * encrypted independently of each other. | |
350 | */ | |
8efc0c15 | 351 | |
352 | void | |
1e3b8b07 | 353 | packet_set_encryption_key(const u_char *key, u_int keylen, |
94ec8c6b | 354 | int number) |
8efc0c15 | 355 | { |
94ec8c6b | 356 | Cipher *cipher = cipher_by_number(number); |
357 | if (cipher == NULL) | |
358 | fatal("packet_set_encryption_key: unknown cipher number %d", number); | |
7e7327a1 | 359 | if (keylen < 20) |
94ec8c6b | 360 | fatal("packet_set_encryption_key: keylen too small: %d", keylen); |
361 | cipher_init(&receive_context, cipher, key, keylen, NULL, 0); | |
362 | cipher_init(&send_context, cipher, key, keylen, NULL, 0); | |
8efc0c15 | 363 | } |
364 | ||
365 | /* Starts constructing a packet to send. */ | |
366 | ||
367 | void | |
7e7327a1 | 368 | packet_start1(int type) |
8efc0c15 | 369 | { |
5260325f | 370 | char buf[9]; |
8efc0c15 | 371 | |
5260325f | 372 | buffer_clear(&outgoing_packet); |
373 | memset(buf, 0, 8); | |
374 | buf[8] = type; | |
375 | buffer_append(&outgoing_packet, buf, 9); | |
8efc0c15 | 376 | } |
377 | ||
7e7327a1 | 378 | void |
379 | packet_start2(int type) | |
380 | { | |
381 | char buf[4+1+1]; | |
382 | ||
383 | buffer_clear(&outgoing_packet); | |
384 | memset(buf, 0, sizeof buf); | |
385 | /* buf[0..3] = payload_len; */ | |
386 | /* buf[4] = pad_len; */ | |
387 | buf[5] = type & 0xff; | |
388 | buffer_append(&outgoing_packet, buf, sizeof buf); | |
389 | } | |
390 | ||
391 | void | |
392 | packet_start(int type) | |
393 | { | |
394 | DBG(debug("packet_start[%d]",type)); | |
395 | if (use_ssh2_packet_format) | |
396 | packet_start2(type); | |
397 | else | |
398 | packet_start1(type); | |
399 | } | |
400 | ||
8efc0c15 | 401 | /* Appends a character to the packet data. */ |
402 | ||
403 | void | |
404 | packet_put_char(int value) | |
405 | { | |
5260325f | 406 | char ch = value; |
407 | buffer_append(&outgoing_packet, &ch, 1); | |
8efc0c15 | 408 | } |
409 | ||
410 | /* Appends an integer to the packet data. */ | |
411 | ||
412 | void | |
1e3b8b07 | 413 | packet_put_int(u_int value) |
8efc0c15 | 414 | { |
5260325f | 415 | buffer_put_int(&outgoing_packet, value); |
8efc0c15 | 416 | } |
417 | ||
418 | /* Appends a string to packet data. */ | |
419 | ||
420 | void | |
1e3b8b07 | 421 | packet_put_string(const char *buf, u_int len) |
8efc0c15 | 422 | { |
5260325f | 423 | buffer_put_string(&outgoing_packet, buf, len); |
8efc0c15 | 424 | } |
7e7327a1 | 425 | void |
426 | packet_put_cstring(const char *str) | |
427 | { | |
428 | buffer_put_string(&outgoing_packet, str, strlen(str)); | |
429 | } | |
430 | ||
431 | void | |
1e3b8b07 | 432 | packet_put_raw(const char *buf, u_int len) |
7e7327a1 | 433 | { |
434 | buffer_append(&outgoing_packet, buf, len); | |
435 | } | |
436 | ||
8efc0c15 | 437 | |
438 | /* Appends an arbitrary precision integer to packet data. */ | |
439 | ||
440 | void | |
5260325f | 441 | packet_put_bignum(BIGNUM * value) |
8efc0c15 | 442 | { |
5260325f | 443 | buffer_put_bignum(&outgoing_packet, value); |
8efc0c15 | 444 | } |
7e7327a1 | 445 | void |
446 | packet_put_bignum2(BIGNUM * value) | |
447 | { | |
448 | buffer_put_bignum2(&outgoing_packet, value); | |
449 | } | |
8efc0c15 | 450 | |
aa3378df | 451 | /* |
452 | * Finalizes and sends the packet. If the encryption key has been set, | |
453 | * encrypts the packet before sending. | |
454 | */ | |
5260325f | 455 | |
8efc0c15 | 456 | void |
7e7327a1 | 457 | packet_send1() |
8efc0c15 | 458 | { |
5260325f | 459 | char buf[8], *cp; |
460 | int i, padding, len; | |
1e3b8b07 | 461 | u_int checksum; |
5260325f | 462 | u_int32_t rand = 0; |
463 | ||
aa3378df | 464 | /* |
465 | * If using packet compression, compress the payload of the outgoing | |
466 | * packet. | |
467 | */ | |
5260325f | 468 | if (packet_compression) { |
469 | buffer_clear(&compression_buffer); | |
470 | /* Skip padding. */ | |
471 | buffer_consume(&outgoing_packet, 8); | |
472 | /* padding */ | |
473 | buffer_append(&compression_buffer, "\0\0\0\0\0\0\0\0", 8); | |
474 | buffer_compress(&outgoing_packet, &compression_buffer); | |
475 | buffer_clear(&outgoing_packet); | |
476 | buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer), | |
477 | buffer_len(&compression_buffer)); | |
478 | } | |
479 | /* Compute packet length without padding (add checksum, remove padding). */ | |
480 | len = buffer_len(&outgoing_packet) + 4 - 8; | |
481 | ||
1d1ffb87 | 482 | /* Insert padding. Initialized to zero in packet_start1() */ |
5260325f | 483 | padding = 8 - len % 8; |
484 | if (cipher_type != SSH_CIPHER_NONE) { | |
485 | cp = buffer_ptr(&outgoing_packet); | |
486 | for (i = 0; i < padding; i++) { | |
487 | if (i % 4 == 0) | |
488 | rand = arc4random(); | |
489 | cp[7 - i] = rand & 0xff; | |
490 | rand >>= 8; | |
491 | } | |
492 | } | |
493 | buffer_consume(&outgoing_packet, 8 - padding); | |
494 | ||
495 | /* Add check bytes. */ | |
1e3b8b07 | 496 | checksum = ssh_crc32((u_char *) buffer_ptr(&outgoing_packet), |
2e73a022 | 497 | buffer_len(&outgoing_packet)); |
5260325f | 498 | PUT_32BIT(buf, checksum); |
499 | buffer_append(&outgoing_packet, buf, 4); | |
8efc0c15 | 500 | |
501 | #ifdef PACKET_DEBUG | |
5260325f | 502 | fprintf(stderr, "packet_send plain: "); |
503 | buffer_dump(&outgoing_packet); | |
8efc0c15 | 504 | #endif |
505 | ||
5260325f | 506 | /* Append to output. */ |
507 | PUT_32BIT(buf, len); | |
508 | buffer_append(&output, buf, 4); | |
509 | buffer_append_space(&output, &cp, buffer_len(&outgoing_packet)); | |
510 | packet_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet), | |
511 | buffer_len(&outgoing_packet)); | |
512 | ||
8efc0c15 | 513 | #ifdef PACKET_DEBUG |
5260325f | 514 | fprintf(stderr, "encrypted: "); |
515 | buffer_dump(&output); | |
8efc0c15 | 516 | #endif |
517 | ||
5260325f | 518 | buffer_clear(&outgoing_packet); |
8efc0c15 | 519 | |
aa3378df | 520 | /* |
521 | * Note that the packet is now only buffered in output. It won\'t be | |
522 | * actually sent until packet_write_wait or packet_write_poll is | |
523 | * called. | |
524 | */ | |
8efc0c15 | 525 | } |
526 | ||
7e7327a1 | 527 | /* |
528 | * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue) | |
529 | */ | |
530 | void | |
531 | packet_send2() | |
532 | { | |
1e3b8b07 | 533 | u_char *macbuf = NULL; |
7e7327a1 | 534 | char *cp; |
1e3b8b07 | 535 | u_int packet_length = 0; |
536 | u_int i, padlen, len; | |
7e7327a1 | 537 | u_int32_t rand = 0; |
1e3b8b07 | 538 | static u_int seqnr = 0; |
7e7327a1 | 539 | int type; |
540 | Enc *enc = NULL; | |
541 | Mac *mac = NULL; | |
542 | Comp *comp = NULL; | |
543 | int block_size; | |
544 | ||
545 | if (kex != NULL) { | |
546 | enc = &kex->enc[MODE_OUT]; | |
547 | mac = &kex->mac[MODE_OUT]; | |
548 | comp = &kex->comp[MODE_OUT]; | |
549 | } | |
94ec8c6b | 550 | block_size = enc ? enc->cipher->block_size : 8; |
7e7327a1 | 551 | |
552 | cp = buffer_ptr(&outgoing_packet); | |
553 | type = cp[5] & 0xff; | |
554 | ||
555 | #ifdef PACKET_DEBUG | |
556 | fprintf(stderr, "plain: "); | |
557 | buffer_dump(&outgoing_packet); | |
558 | #endif | |
559 | ||
560 | if (comp && comp->enabled) { | |
561 | len = buffer_len(&outgoing_packet); | |
562 | /* skip header, compress only payload */ | |
563 | buffer_consume(&outgoing_packet, 5); | |
564 | buffer_clear(&compression_buffer); | |
565 | buffer_compress(&outgoing_packet, &compression_buffer); | |
566 | buffer_clear(&outgoing_packet); | |
567 | buffer_append(&outgoing_packet, "\0\0\0\0\0", 5); | |
568 | buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer), | |
569 | buffer_len(&compression_buffer)); | |
570 | DBG(debug("compression: raw %d compressed %d", len, | |
571 | buffer_len(&outgoing_packet))); | |
572 | } | |
573 | ||
574 | /* sizeof (packet_len + pad_len + payload) */ | |
575 | len = buffer_len(&outgoing_packet); | |
576 | ||
577 | /* | |
578 | * calc size of padding, alloc space, get random data, | |
579 | * minimum padding is 4 bytes | |
580 | */ | |
581 | padlen = block_size - (len % block_size); | |
582 | if (padlen < 4) | |
583 | padlen += block_size; | |
584 | buffer_append_space(&outgoing_packet, &cp, padlen); | |
94ec8c6b | 585 | if (enc && enc->cipher->number != SSH_CIPHER_NONE) { |
1d1ffb87 | 586 | /* random padding */ |
7e7327a1 | 587 | for (i = 0; i < padlen; i++) { |
588 | if (i % 4 == 0) | |
589 | rand = arc4random(); | |
590 | cp[i] = rand & 0xff; | |
591 | rand <<= 8; | |
592 | } | |
1d1ffb87 | 593 | } else { |
594 | /* clear padding */ | |
595 | memset(cp, 0, padlen); | |
7e7327a1 | 596 | } |
597 | /* packet_length includes payload, padding and padding length field */ | |
598 | packet_length = buffer_len(&outgoing_packet) - 4; | |
599 | cp = buffer_ptr(&outgoing_packet); | |
600 | PUT_32BIT(cp, packet_length); | |
601 | cp[4] = padlen & 0xff; | |
602 | DBG(debug("send: len %d (includes padlen %d)", packet_length+4, padlen)); | |
603 | ||
604 | /* compute MAC over seqnr and packet(length fields, payload, padding) */ | |
605 | if (mac && mac->enabled) { | |
606 | macbuf = hmac( mac->md, seqnr, | |
1e3b8b07 | 607 | (u_char *) buffer_ptr(&outgoing_packet), |
7e7327a1 | 608 | buffer_len(&outgoing_packet), |
609 | mac->key, mac->key_len | |
610 | ); | |
94ec8c6b | 611 | DBG(debug("done calc MAC out #%d", seqnr)); |
7e7327a1 | 612 | } |
613 | /* encrypt packet and append to output buffer. */ | |
614 | buffer_append_space(&output, &cp, buffer_len(&outgoing_packet)); | |
615 | packet_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet), | |
616 | buffer_len(&outgoing_packet)); | |
617 | /* append unencrypted MAC */ | |
618 | if (mac && mac->enabled) | |
619 | buffer_append(&output, (char *)macbuf, mac->mac_len); | |
620 | #ifdef PACKET_DEBUG | |
621 | fprintf(stderr, "encrypted: "); | |
622 | buffer_dump(&output); | |
623 | #endif | |
6ae2364d | 624 | /* increment sequence number for outgoing packets */ |
625 | if (++seqnr == 0) | |
626 | log("outgoing seqnr wraps around"); | |
7e7327a1 | 627 | buffer_clear(&outgoing_packet); |
628 | ||
629 | if (type == SSH2_MSG_NEWKEYS) { | |
630 | if (kex==NULL || mac==NULL || enc==NULL || comp==NULL) | |
631 | fatal("packet_send2: no KEX"); | |
632 | if (mac->md != NULL) | |
633 | mac->enabled = 1; | |
94ec8c6b | 634 | DBG(debug("cipher_init send_context")); |
635 | cipher_init(&send_context, enc->cipher, | |
636 | enc->key, enc->cipher->key_len, | |
637 | enc->iv, enc->cipher->block_size); | |
7e7327a1 | 638 | clear_enc_keys(enc, kex->we_need); |
639 | if (comp->type != 0 && comp->enabled == 0) { | |
640 | comp->enabled = 1; | |
641 | if (! packet_compression) | |
642 | packet_start_compression(6); | |
643 | } | |
644 | } | |
645 | } | |
646 | ||
647 | void | |
648 | packet_send() | |
649 | { | |
650 | if (use_ssh2_packet_format) | |
651 | packet_send2(); | |
652 | else | |
653 | packet_send1(); | |
654 | DBG(debug("packet_send done")); | |
655 | } | |
656 | ||
aa3378df | 657 | /* |
658 | * Waits until a packet has been received, and returns its type. Note that | |
659 | * no other data is processed until this returns, so this function should not | |
660 | * be used during the interactive session. | |
661 | */ | |
8efc0c15 | 662 | |
663 | int | |
664 | packet_read(int *payload_len_ptr) | |
665 | { | |
5260325f | 666 | int type, len; |
667 | fd_set set; | |
668 | char buf[8192]; | |
7e7327a1 | 669 | DBG(debug("packet_read()")); |
5260325f | 670 | |
671 | /* Since we are blocking, ensure that all written packets have been sent. */ | |
672 | packet_write_wait(); | |
673 | ||
674 | /* Stay in the loop until we have received a complete packet. */ | |
675 | for (;;) { | |
676 | /* Try to read a packet from the buffer. */ | |
677 | type = packet_read_poll(payload_len_ptr); | |
1d1ffb87 | 678 | if (!use_ssh2_packet_format && ( |
679 | type == SSH_SMSG_SUCCESS | |
5260325f | 680 | || type == SSH_SMSG_FAILURE |
681 | || type == SSH_CMSG_EOF | |
1d1ffb87 | 682 | || type == SSH_CMSG_EXIT_CONFIRMATION)) |
5260325f | 683 | packet_integrity_check(*payload_len_ptr, 0, type); |
684 | /* If we got a packet, return it. */ | |
685 | if (type != SSH_MSG_NONE) | |
686 | return type; | |
aa3378df | 687 | /* |
688 | * Otherwise, wait for some data to arrive, add it to the | |
689 | * buffer, and try again. | |
690 | */ | |
5260325f | 691 | FD_ZERO(&set); |
692 | FD_SET(connection_in, &set); | |
aa3378df | 693 | |
5260325f | 694 | /* Wait for some data to arrive. */ |
695 | select(connection_in + 1, &set, NULL, NULL, NULL); | |
aa3378df | 696 | |
5260325f | 697 | /* Read data from the socket. */ |
698 | len = read(connection_in, buf, sizeof(buf)); | |
89cafde6 | 699 | if (len == 0) { |
700 | log("Connection closed by %.200s", get_remote_ipaddr()); | |
701 | fatal_cleanup(); | |
702 | } | |
5260325f | 703 | if (len < 0) |
704 | fatal("Read from socket failed: %.100s", strerror(errno)); | |
705 | /* Append it to the buffer. */ | |
706 | packet_process_incoming(buf, len); | |
707 | } | |
708 | /* NOTREACHED */ | |
8efc0c15 | 709 | } |
710 | ||
aa3378df | 711 | /* |
712 | * Waits until a packet has been received, verifies that its type matches | |
713 | * that given, and gives a fatal error and exits if there is a mismatch. | |
714 | */ | |
8efc0c15 | 715 | |
716 | void | |
717 | packet_read_expect(int *payload_len_ptr, int expected_type) | |
718 | { | |
5260325f | 719 | int type; |
8efc0c15 | 720 | |
5260325f | 721 | type = packet_read(payload_len_ptr); |
722 | if (type != expected_type) | |
723 | packet_disconnect("Protocol error: expected packet type %d, got %d", | |
7e7327a1 | 724 | expected_type, type); |
8efc0c15 | 725 | } |
726 | ||
727 | /* Checks if a full packet is available in the data received so far via | |
5260325f | 728 | * packet_process_incoming. If so, reads the packet; otherwise returns |
729 | * SSH_MSG_NONE. This does not wait for data from the connection. | |
730 | * | |
731 | * SSH_MSG_DISCONNECT is handled specially here. Also, | |
732 | * SSH_MSG_IGNORE messages are skipped by this function and are never returned | |
733 | * to higher levels. | |
734 | * | |
735 | * The returned payload_len does include space consumed by: | |
736 | * Packet length | |
737 | * Padding | |
738 | * Packet type | |
739 | * Check bytes | |
740 | */ | |
8efc0c15 | 741 | |
742 | int | |
7e7327a1 | 743 | packet_read_poll1(int *payload_len_ptr) |
8efc0c15 | 744 | { |
1e3b8b07 | 745 | u_int len, padded_len; |
746 | u_char *ucp; | |
7e7327a1 | 747 | char buf[8], *cp; |
1e3b8b07 | 748 | u_int checksum, stored_checksum; |
5260325f | 749 | |
5260325f | 750 | /* Check if input size is less than minimum packet size. */ |
751 | if (buffer_len(&input) < 4 + 8) | |
752 | return SSH_MSG_NONE; | |
753 | /* Get length of incoming packet. */ | |
1e3b8b07 | 754 | ucp = (u_char *) buffer_ptr(&input); |
5260325f | 755 | len = GET_32BIT(ucp); |
756 | if (len < 1 + 2 + 2 || len > 256 * 1024) | |
757 | packet_disconnect("Bad packet length %d.", len); | |
758 | padded_len = (len + 8) & ~7; | |
759 | ||
760 | /* Check if the packet has been entirely received. */ | |
761 | if (buffer_len(&input) < 4 + padded_len) | |
762 | return SSH_MSG_NONE; | |
763 | ||
764 | /* The entire packet is in buffer. */ | |
765 | ||
766 | /* Consume packet length. */ | |
767 | buffer_consume(&input, 4); | |
768 | ||
769 | /* Copy data to incoming_packet. */ | |
770 | buffer_clear(&incoming_packet); | |
771 | buffer_append_space(&incoming_packet, &cp, padded_len); | |
772 | packet_decrypt(&receive_context, cp, buffer_ptr(&input), padded_len); | |
773 | buffer_consume(&input, padded_len); | |
8efc0c15 | 774 | |
775 | #ifdef PACKET_DEBUG | |
5260325f | 776 | fprintf(stderr, "read_poll plain: "); |
777 | buffer_dump(&incoming_packet); | |
8efc0c15 | 778 | #endif |
5260325f | 779 | |
780 | /* Compute packet checksum. */ | |
1e3b8b07 | 781 | checksum = ssh_crc32((u_char *) buffer_ptr(&incoming_packet), |
7e7327a1 | 782 | buffer_len(&incoming_packet) - 4); |
5260325f | 783 | |
784 | /* Skip padding. */ | |
785 | buffer_consume(&incoming_packet, 8 - len % 8); | |
786 | ||
787 | /* Test check bytes. */ | |
788 | ||
789 | if (len != buffer_len(&incoming_packet)) | |
790 | packet_disconnect("packet_read_poll: len %d != buffer_len %d.", | |
7e7327a1 | 791 | len, buffer_len(&incoming_packet)); |
5260325f | 792 | |
1e3b8b07 | 793 | ucp = (u_char *) buffer_ptr(&incoming_packet) + len - 4; |
5260325f | 794 | stored_checksum = GET_32BIT(ucp); |
795 | if (checksum != stored_checksum) | |
796 | packet_disconnect("Corrupted check bytes on input."); | |
797 | buffer_consume_end(&incoming_packet, 4); | |
798 | ||
799 | /* If using packet compression, decompress the packet. */ | |
800 | if (packet_compression) { | |
801 | buffer_clear(&compression_buffer); | |
802 | buffer_uncompress(&incoming_packet, &compression_buffer); | |
803 | buffer_clear(&incoming_packet); | |
804 | buffer_append(&incoming_packet, buffer_ptr(&compression_buffer), | |
7e7327a1 | 805 | buffer_len(&compression_buffer)); |
5260325f | 806 | } |
807 | /* Get packet type. */ | |
808 | buffer_get(&incoming_packet, &buf[0], 1); | |
809 | ||
810 | /* Return length of payload (without type field). */ | |
811 | *payload_len_ptr = buffer_len(&incoming_packet); | |
812 | ||
5260325f | 813 | /* Return type. */ |
1e3b8b07 | 814 | return (u_char) buf[0]; |
5260325f | 815 | } |
816 | ||
7e7327a1 | 817 | int |
818 | packet_read_poll2(int *payload_len_ptr) | |
819 | { | |
1e3b8b07 | 820 | u_int padlen, need; |
821 | u_char buf[8], *macbuf; | |
822 | u_char *ucp; | |
7e7327a1 | 823 | char *cp; |
1e3b8b07 | 824 | static u_int packet_length = 0; |
825 | static u_int seqnr = 0; | |
7e7327a1 | 826 | int type; |
827 | int maclen, block_size; | |
828 | Enc *enc = NULL; | |
829 | Mac *mac = NULL; | |
830 | Comp *comp = NULL; | |
831 | ||
832 | if (kex != NULL) { | |
833 | enc = &kex->enc[MODE_IN]; | |
834 | mac = &kex->mac[MODE_IN]; | |
835 | comp = &kex->comp[MODE_IN]; | |
836 | } | |
837 | maclen = mac && mac->enabled ? mac->mac_len : 0; | |
94ec8c6b | 838 | block_size = enc ? enc->cipher->block_size : 8; |
7e7327a1 | 839 | |
840 | if (packet_length == 0) { | |
841 | /* | |
842 | * check if input size is less than the cipher block size, | |
843 | * decrypt first block and extract length of incoming packet | |
844 | */ | |
845 | if (buffer_len(&input) < block_size) | |
846 | return SSH_MSG_NONE; | |
847 | buffer_clear(&incoming_packet); | |
848 | buffer_append_space(&incoming_packet, &cp, block_size); | |
849 | packet_decrypt(&receive_context, cp, buffer_ptr(&input), | |
850 | block_size); | |
1e3b8b07 | 851 | ucp = (u_char *) buffer_ptr(&incoming_packet); |
7e7327a1 | 852 | packet_length = GET_32BIT(ucp); |
853 | if (packet_length < 1 + 4 || packet_length > 256 * 1024) { | |
854 | buffer_dump(&incoming_packet); | |
855 | packet_disconnect("Bad packet length %d.", packet_length); | |
856 | } | |
857 | DBG(debug("input: packet len %d", packet_length+4)); | |
858 | buffer_consume(&input, block_size); | |
859 | } | |
860 | /* we have a partial packet of block_size bytes */ | |
861 | need = 4 + packet_length - block_size; | |
862 | DBG(debug("partial packet %d, need %d, maclen %d", block_size, | |
863 | need, maclen)); | |
864 | if (need % block_size != 0) | |
865 | fatal("padding error: need %d block %d mod %d", | |
866 | need, block_size, need % block_size); | |
867 | /* | |
868 | * check if the entire packet has been received and | |
869 | * decrypt into incoming_packet | |
870 | */ | |
871 | if (buffer_len(&input) < need + maclen) | |
872 | return SSH_MSG_NONE; | |
873 | #ifdef PACKET_DEBUG | |
874 | fprintf(stderr, "read_poll enc/full: "); | |
875 | buffer_dump(&input); | |
876 | #endif | |
877 | buffer_append_space(&incoming_packet, &cp, need); | |
878 | packet_decrypt(&receive_context, cp, buffer_ptr(&input), need); | |
879 | buffer_consume(&input, need); | |
880 | /* | |
881 | * compute MAC over seqnr and packet, | |
882 | * increment sequence number for incoming packet | |
883 | */ | |
6ae2364d | 884 | if (mac && mac->enabled) { |
7e7327a1 | 885 | macbuf = hmac( mac->md, seqnr, |
1e3b8b07 | 886 | (u_char *) buffer_ptr(&incoming_packet), |
7e7327a1 | 887 | buffer_len(&incoming_packet), |
888 | mac->key, mac->key_len | |
889 | ); | |
890 | if (memcmp(macbuf, buffer_ptr(&input), mac->mac_len) != 0) | |
94ec8c6b | 891 | packet_disconnect("Corrupted MAC on input."); |
892 | DBG(debug("MAC #%d ok", seqnr)); | |
7e7327a1 | 893 | buffer_consume(&input, mac->mac_len); |
894 | } | |
6ae2364d | 895 | if (++seqnr == 0) |
896 | log("incoming seqnr wraps around"); | |
7e7327a1 | 897 | |
898 | /* get padlen */ | |
899 | cp = buffer_ptr(&incoming_packet) + 4; | |
900 | padlen = *cp & 0xff; | |
901 | DBG(debug("input: padlen %d", padlen)); | |
902 | if (padlen < 4) | |
903 | packet_disconnect("Corrupted padlen %d on input.", padlen); | |
904 | ||
905 | /* skip packet size + padlen, discard padding */ | |
906 | buffer_consume(&incoming_packet, 4 + 1); | |
907 | buffer_consume_end(&incoming_packet, padlen); | |
908 | ||
909 | DBG(debug("input: len before de-compress %d", buffer_len(&incoming_packet))); | |
910 | if (comp && comp->enabled) { | |
911 | buffer_clear(&compression_buffer); | |
912 | buffer_uncompress(&incoming_packet, &compression_buffer); | |
913 | buffer_clear(&incoming_packet); | |
914 | buffer_append(&incoming_packet, buffer_ptr(&compression_buffer), | |
915 | buffer_len(&compression_buffer)); | |
916 | DBG(debug("input: len after de-compress %d", buffer_len(&incoming_packet))); | |
917 | } | |
918 | /* | |
919 | * get packet type, implies consume. | |
920 | * return length of payload (without type field) | |
921 | */ | |
922 | buffer_get(&incoming_packet, (char *)&buf[0], 1); | |
923 | *payload_len_ptr = buffer_len(&incoming_packet); | |
924 | ||
925 | /* reset for next packet */ | |
926 | packet_length = 0; | |
927 | ||
928 | /* extract packet type */ | |
1e3b8b07 | 929 | type = (u_char)buf[0]; |
7e7327a1 | 930 | |
931 | if (type == SSH2_MSG_NEWKEYS) { | |
932 | if (kex==NULL || mac==NULL || enc==NULL || comp==NULL) | |
933 | fatal("packet_read_poll2: no KEX"); | |
934 | if (mac->md != NULL) | |
935 | mac->enabled = 1; | |
94ec8c6b | 936 | DBG(debug("cipher_init receive_context")); |
937 | cipher_init(&receive_context, enc->cipher, | |
938 | enc->key, enc->cipher->key_len, | |
939 | enc->iv, enc->cipher->block_size); | |
7e7327a1 | 940 | clear_enc_keys(enc, kex->we_need); |
941 | if (comp->type != 0 && comp->enabled == 0) { | |
942 | comp->enabled = 1; | |
943 | if (! packet_compression) | |
944 | packet_start_compression(6); | |
945 | } | |
946 | } | |
947 | ||
948 | #ifdef PACKET_DEBUG | |
949 | fprintf(stderr, "read/plain[%d]:\r\n",type); | |
950 | buffer_dump(&incoming_packet); | |
951 | #endif | |
1e3b8b07 | 952 | return (u_char)type; |
7e7327a1 | 953 | } |
954 | ||
955 | int | |
956 | packet_read_poll(int *payload_len_ptr) | |
957 | { | |
958 | char *msg; | |
959 | for (;;) { | |
960 | int type = use_ssh2_packet_format ? | |
961 | packet_read_poll2(payload_len_ptr): | |
962 | packet_read_poll1(payload_len_ptr); | |
963 | ||
964 | if(compat20) { | |
965 | int reason; | |
966 | if (type != 0) | |
967 | DBG(debug("received packet type %d", type)); | |
968 | switch(type) { | |
969 | case SSH2_MSG_IGNORE: | |
970 | break; | |
971 | case SSH2_MSG_DEBUG: | |
972 | packet_get_char(); | |
973 | msg = packet_get_string(NULL); | |
974 | debug("Remote: %.900s", msg); | |
975 | xfree(msg); | |
976 | msg = packet_get_string(NULL); | |
977 | xfree(msg); | |
978 | break; | |
979 | case SSH2_MSG_DISCONNECT: | |
980 | reason = packet_get_int(); | |
981 | msg = packet_get_string(NULL); | |
7c49df64 | 982 | log("Received disconnect from %s: %d: %.400s", get_remote_ipaddr(), |
983 | reason, msg); | |
7e7327a1 | 984 | xfree(msg); |
985 | fatal_cleanup(); | |
986 | break; | |
987 | default: | |
988 | return type; | |
989 | break; | |
990 | } | |
991 | } else { | |
992 | switch(type) { | |
993 | case SSH_MSG_IGNORE: | |
994 | break; | |
995 | case SSH_MSG_DEBUG: | |
996 | msg = packet_get_string(NULL); | |
997 | debug("Remote: %.900s", msg); | |
998 | xfree(msg); | |
999 | break; | |
1000 | case SSH_MSG_DISCONNECT: | |
1001 | msg = packet_get_string(NULL); | |
7c49df64 | 1002 | log("Received disconnect from %s: %.400s", get_remote_ipaddr(), |
1003 | msg); | |
7e7327a1 | 1004 | fatal_cleanup(); |
1005 | xfree(msg); | |
1006 | break; | |
1007 | default: | |
1008 | if (type != 0) | |
1009 | DBG(debug("received packet type %d", type)); | |
1010 | return type; | |
1011 | break; | |
1012 | } | |
1013 | } | |
1014 | } | |
1015 | } | |
1016 | ||
aa3378df | 1017 | /* |
1018 | * Buffers the given amount of input characters. This is intended to be used | |
1019 | * together with packet_read_poll. | |
1020 | */ | |
8efc0c15 | 1021 | |
1022 | void | |
1e3b8b07 | 1023 | packet_process_incoming(const char *buf, u_int len) |
8efc0c15 | 1024 | { |
5260325f | 1025 | buffer_append(&input, buf, len); |
8efc0c15 | 1026 | } |
1027 | ||
1028 | /* Returns a character from the packet. */ | |
1029 | ||
1e3b8b07 | 1030 | u_int |
8efc0c15 | 1031 | packet_get_char() |
1032 | { | |
5260325f | 1033 | char ch; |
1034 | buffer_get(&incoming_packet, &ch, 1); | |
1e3b8b07 | 1035 | return (u_char) ch; |
8efc0c15 | 1036 | } |
1037 | ||
1038 | /* Returns an integer from the packet data. */ | |
1039 | ||
1e3b8b07 | 1040 | u_int |
8efc0c15 | 1041 | packet_get_int() |
1042 | { | |
5260325f | 1043 | return buffer_get_int(&incoming_packet); |
8efc0c15 | 1044 | } |
1045 | ||
aa3378df | 1046 | /* |
1047 | * Returns an arbitrary precision integer from the packet data. The integer | |
1048 | * must have been initialized before this call. | |
1049 | */ | |
8efc0c15 | 1050 | |
1051 | void | |
5260325f | 1052 | packet_get_bignum(BIGNUM * value, int *length_ptr) |
8efc0c15 | 1053 | { |
5260325f | 1054 | *length_ptr = buffer_get_bignum(&incoming_packet, value); |
8efc0c15 | 1055 | } |
1056 | ||
7e7327a1 | 1057 | void |
1058 | packet_get_bignum2(BIGNUM * value, int *length_ptr) | |
1059 | { | |
1060 | *length_ptr = buffer_get_bignum2(&incoming_packet, value); | |
1061 | } | |
1062 | ||
1063 | char * | |
1064 | packet_get_raw(int *length_ptr) | |
1065 | { | |
1066 | int bytes = buffer_len(&incoming_packet); | |
1067 | if (length_ptr != NULL) | |
1068 | *length_ptr = bytes; | |
1069 | return buffer_ptr(&incoming_packet); | |
1070 | } | |
1071 | ||
6ae2364d | 1072 | int |
1073 | packet_remaining(void) | |
1074 | { | |
1075 | return buffer_len(&incoming_packet); | |
1076 | } | |
1077 | ||
aa3378df | 1078 | /* |
1079 | * Returns a string from the packet data. The string is allocated using | |
1080 | * xmalloc; it is the responsibility of the calling program to free it when | |
1081 | * no longer needed. The length_ptr argument may be NULL, or point to an | |
1082 | * integer into which the length of the string is stored. | |
1083 | */ | |
8efc0c15 | 1084 | |
aa3378df | 1085 | char * |
1e3b8b07 | 1086 | packet_get_string(u_int *length_ptr) |
8efc0c15 | 1087 | { |
5260325f | 1088 | return buffer_get_string(&incoming_packet, length_ptr); |
8efc0c15 | 1089 | } |
1090 | ||
aa3378df | 1091 | /* |
1092 | * Sends a diagnostic message from the server to the client. This message | |
1093 | * can be sent at any time (but not while constructing another message). The | |
1094 | * message is printed immediately, but only if the client is being executed | |
1095 | * in verbose mode. These messages are primarily intended to ease debugging | |
1096 | * authentication problems. The length of the formatted message must not | |
1097 | * exceed 1024 bytes. This will automatically call packet_write_wait. | |
1098 | */ | |
8efc0c15 | 1099 | |
1100 | void | |
5260325f | 1101 | packet_send_debug(const char *fmt,...) |
8efc0c15 | 1102 | { |
5260325f | 1103 | char buf[1024]; |
1104 | va_list args; | |
1105 | ||
f72fc97f | 1106 | if (compat20 && (datafellows & SSH_BUG_DEBUG)) |
1107 | return; | |
1108 | ||
5260325f | 1109 | va_start(args, fmt); |
1110 | vsnprintf(buf, sizeof(buf), fmt, args); | |
1111 | va_end(args); | |
1112 | ||
c4bc58eb | 1113 | if (compat20) { |
1114 | packet_start(SSH2_MSG_DEBUG); | |
1115 | packet_put_char(0); /* bool: always display */ | |
1116 | packet_put_cstring(buf); | |
1117 | packet_put_cstring(""); | |
1118 | } else { | |
1119 | packet_start(SSH_MSG_DEBUG); | |
1120 | packet_put_cstring(buf); | |
1121 | } | |
5260325f | 1122 | packet_send(); |
1123 | packet_write_wait(); | |
8efc0c15 | 1124 | } |
1125 | ||
aa3378df | 1126 | /* |
1127 | * Logs the error plus constructs and sends a disconnect packet, closes the | |
1128 | * connection, and exits. This function never returns. The error message | |
1129 | * should not contain a newline. The length of the formatted message must | |
1130 | * not exceed 1024 bytes. | |
1131 | */ | |
8efc0c15 | 1132 | |
1133 | void | |
5260325f | 1134 | packet_disconnect(const char *fmt,...) |
1135 | { | |
1136 | char buf[1024]; | |
1137 | va_list args; | |
1138 | static int disconnecting = 0; | |
1139 | if (disconnecting) /* Guard against recursive invocations. */ | |
1140 | fatal("packet_disconnect called recursively."); | |
1141 | disconnecting = 1; | |
1142 | ||
aa3378df | 1143 | /* |
1144 | * Format the message. Note that the caller must make sure the | |
1145 | * message is of limited size. | |
1146 | */ | |
5260325f | 1147 | va_start(args, fmt); |
1148 | vsnprintf(buf, sizeof(buf), fmt, args); | |
1149 | va_end(args); | |
1150 | ||
1151 | /* Send the disconnect message to the other side, and wait for it to get sent. */ | |
7e7327a1 | 1152 | if (compat20) { |
1153 | packet_start(SSH2_MSG_DISCONNECT); | |
1154 | packet_put_int(SSH2_DISCONNECT_PROTOCOL_ERROR); | |
1155 | packet_put_cstring(buf); | |
1156 | packet_put_cstring(""); | |
1157 | } else { | |
1158 | packet_start(SSH_MSG_DISCONNECT); | |
1159 | packet_put_string(buf, strlen(buf)); | |
1160 | } | |
5260325f | 1161 | packet_send(); |
1162 | packet_write_wait(); | |
1163 | ||
1164 | /* Stop listening for connections. */ | |
1165 | channel_stop_listening(); | |
1166 | ||
1167 | /* Close the connection. */ | |
1168 | packet_close(); | |
1169 | ||
1170 | /* Display the error locally and exit. */ | |
57112b5a | 1171 | log("Disconnecting: %.100s", buf); |
1172 | fatal_cleanup(); | |
8efc0c15 | 1173 | } |
1174 | ||
aa3378df | 1175 | /* Checks if there is any buffered output, and tries to write some of the output. */ |
8efc0c15 | 1176 | |
1177 | void | |
1178 | packet_write_poll() | |
1179 | { | |
5260325f | 1180 | int len = buffer_len(&output); |
1181 | if (len > 0) { | |
1182 | len = write(connection_out, buffer_ptr(&output), len); | |
1183 | if (len <= 0) { | |
1184 | if (errno == EAGAIN) | |
1185 | return; | |
1186 | else | |
1187 | fatal("Write failed: %.100s", strerror(errno)); | |
1188 | } | |
1189 | buffer_consume(&output, len); | |
1190 | } | |
8efc0c15 | 1191 | } |
1192 | ||
aa3378df | 1193 | /* |
1194 | * Calls packet_write_poll repeatedly until all pending output data has been | |
1195 | * written. | |
1196 | */ | |
8efc0c15 | 1197 | |
1198 | void | |
1199 | packet_write_wait() | |
1200 | { | |
5260325f | 1201 | packet_write_poll(); |
1202 | while (packet_have_data_to_write()) { | |
1203 | fd_set set; | |
1204 | FD_ZERO(&set); | |
1205 | FD_SET(connection_out, &set); | |
1206 | select(connection_out + 1, NULL, &set, NULL, NULL); | |
1207 | packet_write_poll(); | |
1208 | } | |
8efc0c15 | 1209 | } |
1210 | ||
1211 | /* Returns true if there is buffered data to write to the connection. */ | |
1212 | ||
1213 | int | |
1214 | packet_have_data_to_write() | |
1215 | { | |
5260325f | 1216 | return buffer_len(&output) != 0; |
8efc0c15 | 1217 | } |
1218 | ||
1219 | /* Returns true if there is not too much data to write to the connection. */ | |
1220 | ||
1221 | int | |
1222 | packet_not_very_much_data_to_write() | |
1223 | { | |
5260325f | 1224 | if (interactive_mode) |
1225 | return buffer_len(&output) < 16384; | |
1226 | else | |
1227 | return buffer_len(&output) < 128 * 1024; | |
8efc0c15 | 1228 | } |
1229 | ||
1230 | /* Informs that the current session is interactive. Sets IP flags for that. */ | |
1231 | ||
1232 | void | |
1233 | packet_set_interactive(int interactive, int keepalives) | |
1234 | { | |
5260325f | 1235 | int on = 1; |
1236 | ||
1237 | /* Record that we are in interactive mode. */ | |
1238 | interactive_mode = interactive; | |
1239 | ||
48e671d5 | 1240 | /* Only set socket options if using a socket. */ |
1241 | if (!packet_connection_is_on_socket()) | |
5260325f | 1242 | return; |
5260325f | 1243 | if (keepalives) { |
1244 | /* Set keepalives if requested. */ | |
1245 | if (setsockopt(connection_in, SOL_SOCKET, SO_KEEPALIVE, (void *) &on, | |
48e671d5 | 1246 | sizeof(on)) < 0) |
5260325f | 1247 | error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); |
1248 | } | |
48e671d5 | 1249 | /* |
1250 | * IPTOS_LOWDELAY, TCP_NODELAY and IPTOS_THROUGHPUT are IPv4 only | |
1251 | */ | |
1252 | if (!packet_connection_is_ipv4()) | |
1253 | return; | |
5260325f | 1254 | if (interactive) { |
aa3378df | 1255 | /* |
1256 | * Set IP options for an interactive connection. Use | |
1257 | * IPTOS_LOWDELAY and TCP_NODELAY. | |
1258 | */ | |
132dd316 | 1259 | #if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN) |
5260325f | 1260 | int lowdelay = IPTOS_LOWDELAY; |
1261 | if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, (void *) &lowdelay, | |
48e671d5 | 1262 | sizeof(lowdelay)) < 0) |
5260325f | 1263 | error("setsockopt IPTOS_LOWDELAY: %.100s", strerror(errno)); |
c04f75f1 | 1264 | #endif |
5260325f | 1265 | if (setsockopt(connection_in, IPPROTO_TCP, TCP_NODELAY, (void *) &on, |
48e671d5 | 1266 | sizeof(on)) < 0) |
5260325f | 1267 | error("setsockopt TCP_NODELAY: %.100s", strerror(errno)); |
1268 | } else { | |
aa3378df | 1269 | /* |
1270 | * Set IP options for a non-interactive connection. Use | |
1271 | * IPTOS_THROUGHPUT. | |
1272 | */ | |
132dd316 | 1273 | #if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN) |
5260325f | 1274 | int throughput = IPTOS_THROUGHPUT; |
1275 | if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, (void *) &throughput, | |
48e671d5 | 1276 | sizeof(throughput)) < 0) |
5260325f | 1277 | error("setsockopt IPTOS_THROUGHPUT: %.100s", strerror(errno)); |
c04f75f1 | 1278 | #endif |
5260325f | 1279 | } |
8efc0c15 | 1280 | } |
1281 | ||
1282 | /* Returns true if the current connection is interactive. */ | |
1283 | ||
1284 | int | |
1285 | packet_is_interactive() | |
1286 | { | |
5260325f | 1287 | return interactive_mode; |
8efc0c15 | 1288 | } |
9d6b7add | 1289 | |
1290 | int | |
1291 | packet_set_maxsize(int s) | |
1292 | { | |
5260325f | 1293 | static int called = 0; |
1294 | if (called) { | |
7e7327a1 | 1295 | log("packet_set_maxsize: called twice: old %d new %d", |
1296 | max_packet_size, s); | |
5260325f | 1297 | return -1; |
1298 | } | |
1299 | if (s < 4 * 1024 || s > 1024 * 1024) { | |
1300 | log("packet_set_maxsize: bad size %d", s); | |
1301 | return -1; | |
1302 | } | |
1303 | log("packet_set_maxsize: setting to %d", s); | |
1304 | max_packet_size = s; | |
1305 | return s; | |
9d6b7add | 1306 | } |