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Commit | Line | Data |
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8efc0c15 | 1 | /* |
5260325f | 2 | * |
3 | * packet.c | |
4 | * | |
5 | * Author: Tatu Ylonen <ylo@cs.hut.fi> | |
6 | * | |
7 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland | |
8 | * All rights reserved | |
9 | * | |
10 | * Created: Sat Mar 18 02:40:40 1995 ylo | |
11 | * | |
12 | * This file contains code implementing the packet protocol and communication | |
13 | * with the other side. This same code is used both on client and server side. | |
14 | * | |
15 | */ | |
8efc0c15 | 16 | |
17 | #include "includes.h" | |
18 | RCSID("$Id$"); | |
19 | ||
20 | #include "xmalloc.h" | |
21 | #include "buffer.h" | |
22 | #include "packet.h" | |
23 | #include "bufaux.h" | |
24 | #include "ssh.h" | |
25 | #include "crc32.h" | |
26 | #include "cipher.h" | |
27 | #include "getput.h" | |
28 | ||
29 | #include "compress.h" | |
30 | #include "deattack.h" | |
31 | ||
aa3378df | 32 | /* |
33 | * This variable contains the file descriptors used for communicating with | |
34 | * the other side. connection_in is used for reading; connection_out for | |
35 | * writing. These can be the same descriptor, in which case it is assumed to | |
36 | * be a socket. | |
37 | */ | |
8efc0c15 | 38 | static int connection_in = -1; |
39 | static int connection_out = -1; | |
40 | ||
aa3378df | 41 | /* |
42 | * Cipher type. This value is only used to determine whether to pad the | |
43 | * packets with zeroes or random data. | |
44 | */ | |
8efc0c15 | 45 | static int cipher_type = SSH_CIPHER_NONE; |
46 | ||
47 | /* Protocol flags for the remote side. */ | |
48 | static unsigned int remote_protocol_flags = 0; | |
49 | ||
50 | /* Encryption context for receiving data. This is only used for decryption. */ | |
51 | static CipherContext receive_context; | |
5260325f | 52 | |
53 | /* Encryption context for sending data. This is only used for encryption. */ | |
8efc0c15 | 54 | static CipherContext send_context; |
55 | ||
56 | /* Buffer for raw input data from the socket. */ | |
57 | static Buffer input; | |
58 | ||
59 | /* Buffer for raw output data going to the socket. */ | |
60 | static Buffer output; | |
61 | ||
62 | /* Buffer for the partial outgoing packet being constructed. */ | |
63 | static Buffer outgoing_packet; | |
64 | ||
65 | /* Buffer for the incoming packet currently being processed. */ | |
66 | static Buffer incoming_packet; | |
67 | ||
68 | /* Scratch buffer for packet compression/decompression. */ | |
69 | static Buffer compression_buffer; | |
70 | ||
71 | /* Flag indicating whether packet compression/decompression is enabled. */ | |
72 | static int packet_compression = 0; | |
73 | ||
9d6b7add | 74 | /* default maximum packet size */ |
75 | int max_packet_size = 32768; | |
76 | ||
8efc0c15 | 77 | /* Flag indicating whether this module has been initialized. */ |
78 | static int initialized = 0; | |
79 | ||
80 | /* Set to true if the connection is interactive. */ | |
81 | static int interactive_mode = 0; | |
82 | ||
aa3378df | 83 | /* |
84 | * Sets the descriptors used for communication. Disables encryption until | |
85 | * packet_set_encryption_key is called. | |
86 | */ | |
8efc0c15 | 87 | |
88 | void | |
89 | packet_set_connection(int fd_in, int fd_out) | |
90 | { | |
5260325f | 91 | connection_in = fd_in; |
92 | connection_out = fd_out; | |
93 | cipher_type = SSH_CIPHER_NONE; | |
94 | cipher_set_key(&send_context, SSH_CIPHER_NONE, (unsigned char *) "", 0, 1); | |
95 | cipher_set_key(&receive_context, SSH_CIPHER_NONE, (unsigned char *) "", 0, 0); | |
96 | if (!initialized) { | |
97 | initialized = 1; | |
98 | buffer_init(&input); | |
99 | buffer_init(&output); | |
100 | buffer_init(&outgoing_packet); | |
101 | buffer_init(&incoming_packet); | |
102 | } | |
103 | /* Kludge: arrange the close function to be called from fatal(). */ | |
104 | fatal_add_cleanup((void (*) (void *)) packet_close, NULL); | |
8efc0c15 | 105 | } |
106 | ||
48e671d5 | 107 | /* Returns 1 if remote host is connected via socket, 0 if not. */ |
108 | ||
109 | int | |
110 | packet_connection_is_on_socket() | |
111 | { | |
112 | struct sockaddr_storage from, to; | |
113 | socklen_t fromlen, tolen; | |
114 | ||
115 | /* filedescriptors in and out are the same, so it's a socket */ | |
116 | if (connection_in == connection_out) | |
117 | return 1; | |
118 | fromlen = sizeof(from); | |
119 | memset(&from, 0, sizeof(from)); | |
9bc5ddfe | 120 | if (getpeername(connection_in, (struct sockaddr *)&from, &fromlen) < 0) |
48e671d5 | 121 | return 0; |
122 | tolen = sizeof(to); | |
123 | memset(&to, 0, sizeof(to)); | |
9bc5ddfe | 124 | if (getpeername(connection_out, (struct sockaddr *)&to, &tolen) < 0) |
48e671d5 | 125 | return 0; |
126 | if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0) | |
127 | return 0; | |
128 | if (from.ss_family != AF_INET && from.ss_family != AF_INET6) | |
129 | return 0; | |
130 | return 1; | |
131 | } | |
132 | ||
133 | /* returns 1 if connection is via ipv4 */ | |
134 | ||
135 | int | |
136 | packet_connection_is_ipv4() | |
137 | { | |
138 | struct sockaddr_storage to; | |
139 | socklen_t tolen; | |
140 | ||
141 | memset(&to, 0, sizeof(to)); | |
142 | if (getsockname(connection_out, (struct sockaddr *)&to, &tolen) < 0) | |
143 | return 0; | |
144 | if (to.ss_family != AF_INET) | |
145 | return 0; | |
146 | return 1; | |
147 | } | |
148 | ||
8efc0c15 | 149 | /* Sets the connection into non-blocking mode. */ |
150 | ||
151 | void | |
152 | packet_set_nonblocking() | |
153 | { | |
5260325f | 154 | /* Set the socket into non-blocking mode. */ |
155 | if (fcntl(connection_in, F_SETFL, O_NONBLOCK) < 0) | |
156 | error("fcntl O_NONBLOCK: %.100s", strerror(errno)); | |
8efc0c15 | 157 | |
5260325f | 158 | if (connection_out != connection_in) { |
159 | if (fcntl(connection_out, F_SETFL, O_NONBLOCK) < 0) | |
160 | error("fcntl O_NONBLOCK: %.100s", strerror(errno)); | |
161 | } | |
8efc0c15 | 162 | } |
163 | ||
164 | /* Returns the socket used for reading. */ | |
165 | ||
166 | int | |
167 | packet_get_connection_in() | |
168 | { | |
5260325f | 169 | return connection_in; |
8efc0c15 | 170 | } |
171 | ||
172 | /* Returns the descriptor used for writing. */ | |
173 | ||
174 | int | |
175 | packet_get_connection_out() | |
176 | { | |
5260325f | 177 | return connection_out; |
8efc0c15 | 178 | } |
179 | ||
180 | /* Closes the connection and clears and frees internal data structures. */ | |
181 | ||
182 | void | |
183 | packet_close() | |
184 | { | |
5260325f | 185 | if (!initialized) |
186 | return; | |
187 | initialized = 0; | |
188 | if (connection_in == connection_out) { | |
189 | shutdown(connection_out, SHUT_RDWR); | |
190 | close(connection_out); | |
191 | } else { | |
192 | close(connection_in); | |
193 | close(connection_out); | |
194 | } | |
195 | buffer_free(&input); | |
196 | buffer_free(&output); | |
197 | buffer_free(&outgoing_packet); | |
198 | buffer_free(&incoming_packet); | |
199 | if (packet_compression) { | |
200 | buffer_free(&compression_buffer); | |
201 | buffer_compress_uninit(); | |
202 | } | |
8efc0c15 | 203 | } |
204 | ||
205 | /* Sets remote side protocol flags. */ | |
206 | ||
207 | void | |
208 | packet_set_protocol_flags(unsigned int protocol_flags) | |
209 | { | |
5260325f | 210 | remote_protocol_flags = protocol_flags; |
211 | channel_set_options((protocol_flags & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) != 0); | |
8efc0c15 | 212 | } |
213 | ||
214 | /* Returns the remote protocol flags set earlier by the above function. */ | |
215 | ||
216 | unsigned int | |
217 | packet_get_protocol_flags() | |
218 | { | |
5260325f | 219 | return remote_protocol_flags; |
8efc0c15 | 220 | } |
221 | ||
aa3378df | 222 | /* |
223 | * Starts packet compression from the next packet on in both directions. | |
224 | * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip. | |
225 | */ | |
8efc0c15 | 226 | |
227 | void | |
228 | packet_start_compression(int level) | |
229 | { | |
5260325f | 230 | if (packet_compression) |
231 | fatal("Compression already enabled."); | |
232 | packet_compression = 1; | |
233 | buffer_init(&compression_buffer); | |
234 | buffer_compress_init(level); | |
8efc0c15 | 235 | } |
236 | ||
aa3378df | 237 | /* |
238 | * Encrypts the given number of bytes, copying from src to dest. bytes is | |
239 | * known to be a multiple of 8. | |
240 | */ | |
8efc0c15 | 241 | |
242 | void | |
5260325f | 243 | packet_encrypt(CipherContext * cc, void *dest, void *src, |
8efc0c15 | 244 | unsigned int bytes) |
245 | { | |
5260325f | 246 | cipher_encrypt(cc, dest, src, bytes); |
8efc0c15 | 247 | } |
248 | ||
aa3378df | 249 | /* |
250 | * Decrypts the given number of bytes, copying from src to dest. bytes is | |
251 | * known to be a multiple of 8. | |
252 | */ | |
8efc0c15 | 253 | |
254 | void | |
5260325f | 255 | packet_decrypt(CipherContext * cc, void *dest, void *src, |
8efc0c15 | 256 | unsigned int bytes) |
257 | { | |
5260325f | 258 | int i; |
259 | ||
260 | if ((bytes % 8) != 0) | |
261 | fatal("packet_decrypt: bad ciphertext length %d", bytes); | |
262 | ||
aa3378df | 263 | /* |
264 | * Cryptographic attack detector for ssh - Modifications for packet.c | |
265 | * (C)1998 CORE-SDI, Buenos Aires Argentina Ariel Futoransky(futo@core-sdi.com) | |
266 | */ | |
5260325f | 267 | |
268 | switch (cc->type) { | |
269 | case SSH_CIPHER_NONE: | |
270 | i = DEATTACK_OK; | |
271 | break; | |
272 | default: | |
273 | i = detect_attack(src, bytes, NULL); | |
274 | break; | |
275 | } | |
276 | ||
277 | if (i == DEATTACK_DETECTED) | |
278 | packet_disconnect("crc32 compensation attack: network attack detected"); | |
279 | ||
280 | cipher_decrypt(cc, dest, src, bytes); | |
8efc0c15 | 281 | } |
282 | ||
aa3378df | 283 | /* |
284 | * Causes any further packets to be encrypted using the given key. The same | |
285 | * key is used for both sending and reception. However, both directions are | |
286 | * encrypted independently of each other. | |
287 | */ | |
8efc0c15 | 288 | |
289 | void | |
290 | packet_set_encryption_key(const unsigned char *key, unsigned int keylen, | |
4d195447 | 291 | int cipher) |
8efc0c15 | 292 | { |
5260325f | 293 | /* All other ciphers use the same key in both directions for now. */ |
294 | cipher_set_key(&receive_context, cipher, key, keylen, 0); | |
295 | cipher_set_key(&send_context, cipher, key, keylen, 1); | |
8efc0c15 | 296 | } |
297 | ||
298 | /* Starts constructing a packet to send. */ | |
299 | ||
300 | void | |
301 | packet_start(int type) | |
302 | { | |
5260325f | 303 | char buf[9]; |
8efc0c15 | 304 | |
5260325f | 305 | buffer_clear(&outgoing_packet); |
306 | memset(buf, 0, 8); | |
307 | buf[8] = type; | |
308 | buffer_append(&outgoing_packet, buf, 9); | |
8efc0c15 | 309 | } |
310 | ||
311 | /* Appends a character to the packet data. */ | |
312 | ||
313 | void | |
314 | packet_put_char(int value) | |
315 | { | |
5260325f | 316 | char ch = value; |
317 | buffer_append(&outgoing_packet, &ch, 1); | |
8efc0c15 | 318 | } |
319 | ||
320 | /* Appends an integer to the packet data. */ | |
321 | ||
322 | void | |
323 | packet_put_int(unsigned int value) | |
324 | { | |
5260325f | 325 | buffer_put_int(&outgoing_packet, value); |
8efc0c15 | 326 | } |
327 | ||
328 | /* Appends a string to packet data. */ | |
329 | ||
330 | void | |
331 | packet_put_string(const char *buf, unsigned int len) | |
332 | { | |
5260325f | 333 | buffer_put_string(&outgoing_packet, buf, len); |
8efc0c15 | 334 | } |
335 | ||
336 | /* Appends an arbitrary precision integer to packet data. */ | |
337 | ||
338 | void | |
5260325f | 339 | packet_put_bignum(BIGNUM * value) |
8efc0c15 | 340 | { |
5260325f | 341 | buffer_put_bignum(&outgoing_packet, value); |
8efc0c15 | 342 | } |
343 | ||
aa3378df | 344 | /* |
345 | * Finalizes and sends the packet. If the encryption key has been set, | |
346 | * encrypts the packet before sending. | |
347 | */ | |
5260325f | 348 | |
8efc0c15 | 349 | void |
350 | packet_send() | |
351 | { | |
5260325f | 352 | char buf[8], *cp; |
353 | int i, padding, len; | |
354 | unsigned int checksum; | |
355 | u_int32_t rand = 0; | |
356 | ||
aa3378df | 357 | /* |
358 | * If using packet compression, compress the payload of the outgoing | |
359 | * packet. | |
360 | */ | |
5260325f | 361 | if (packet_compression) { |
362 | buffer_clear(&compression_buffer); | |
363 | /* Skip padding. */ | |
364 | buffer_consume(&outgoing_packet, 8); | |
365 | /* padding */ | |
366 | buffer_append(&compression_buffer, "\0\0\0\0\0\0\0\0", 8); | |
367 | buffer_compress(&outgoing_packet, &compression_buffer); | |
368 | buffer_clear(&outgoing_packet); | |
369 | buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer), | |
370 | buffer_len(&compression_buffer)); | |
371 | } | |
372 | /* Compute packet length without padding (add checksum, remove padding). */ | |
373 | len = buffer_len(&outgoing_packet) + 4 - 8; | |
374 | ||
375 | /* Insert padding. */ | |
376 | padding = 8 - len % 8; | |
377 | if (cipher_type != SSH_CIPHER_NONE) { | |
378 | cp = buffer_ptr(&outgoing_packet); | |
379 | for (i = 0; i < padding; i++) { | |
380 | if (i % 4 == 0) | |
381 | rand = arc4random(); | |
382 | cp[7 - i] = rand & 0xff; | |
383 | rand >>= 8; | |
384 | } | |
385 | } | |
386 | buffer_consume(&outgoing_packet, 8 - padding); | |
387 | ||
388 | /* Add check bytes. */ | |
389 | checksum = crc32((unsigned char *) buffer_ptr(&outgoing_packet), | |
390 | buffer_len(&outgoing_packet)); | |
391 | PUT_32BIT(buf, checksum); | |
392 | buffer_append(&outgoing_packet, buf, 4); | |
8efc0c15 | 393 | |
394 | #ifdef PACKET_DEBUG | |
5260325f | 395 | fprintf(stderr, "packet_send plain: "); |
396 | buffer_dump(&outgoing_packet); | |
8efc0c15 | 397 | #endif |
398 | ||
5260325f | 399 | /* Append to output. */ |
400 | PUT_32BIT(buf, len); | |
401 | buffer_append(&output, buf, 4); | |
402 | buffer_append_space(&output, &cp, buffer_len(&outgoing_packet)); | |
403 | packet_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet), | |
404 | buffer_len(&outgoing_packet)); | |
405 | ||
8efc0c15 | 406 | #ifdef PACKET_DEBUG |
5260325f | 407 | fprintf(stderr, "encrypted: "); |
408 | buffer_dump(&output); | |
8efc0c15 | 409 | #endif |
410 | ||
5260325f | 411 | buffer_clear(&outgoing_packet); |
8efc0c15 | 412 | |
aa3378df | 413 | /* |
414 | * Note that the packet is now only buffered in output. It won\'t be | |
415 | * actually sent until packet_write_wait or packet_write_poll is | |
416 | * called. | |
417 | */ | |
8efc0c15 | 418 | } |
419 | ||
aa3378df | 420 | /* |
421 | * Waits until a packet has been received, and returns its type. Note that | |
422 | * no other data is processed until this returns, so this function should not | |
423 | * be used during the interactive session. | |
424 | */ | |
8efc0c15 | 425 | |
426 | int | |
427 | packet_read(int *payload_len_ptr) | |
428 | { | |
5260325f | 429 | int type, len; |
430 | fd_set set; | |
431 | char buf[8192]; | |
432 | ||
433 | /* Since we are blocking, ensure that all written packets have been sent. */ | |
434 | packet_write_wait(); | |
435 | ||
436 | /* Stay in the loop until we have received a complete packet. */ | |
437 | for (;;) { | |
438 | /* Try to read a packet from the buffer. */ | |
439 | type = packet_read_poll(payload_len_ptr); | |
440 | if (type == SSH_SMSG_SUCCESS | |
441 | || type == SSH_SMSG_FAILURE | |
442 | || type == SSH_CMSG_EOF | |
443 | || type == SSH_CMSG_EXIT_CONFIRMATION) | |
444 | packet_integrity_check(*payload_len_ptr, 0, type); | |
445 | /* If we got a packet, return it. */ | |
446 | if (type != SSH_MSG_NONE) | |
447 | return type; | |
aa3378df | 448 | /* |
449 | * Otherwise, wait for some data to arrive, add it to the | |
450 | * buffer, and try again. | |
451 | */ | |
5260325f | 452 | FD_ZERO(&set); |
453 | FD_SET(connection_in, &set); | |
aa3378df | 454 | |
5260325f | 455 | /* Wait for some data to arrive. */ |
456 | select(connection_in + 1, &set, NULL, NULL, NULL); | |
aa3378df | 457 | |
5260325f | 458 | /* Read data from the socket. */ |
459 | len = read(connection_in, buf, sizeof(buf)); | |
89cafde6 | 460 | if (len == 0) { |
461 | log("Connection closed by %.200s", get_remote_ipaddr()); | |
462 | fatal_cleanup(); | |
463 | } | |
5260325f | 464 | if (len < 0) |
465 | fatal("Read from socket failed: %.100s", strerror(errno)); | |
466 | /* Append it to the buffer. */ | |
467 | packet_process_incoming(buf, len); | |
468 | } | |
469 | /* NOTREACHED */ | |
8efc0c15 | 470 | } |
471 | ||
aa3378df | 472 | /* |
473 | * Waits until a packet has been received, verifies that its type matches | |
474 | * that given, and gives a fatal error and exits if there is a mismatch. | |
475 | */ | |
8efc0c15 | 476 | |
477 | void | |
478 | packet_read_expect(int *payload_len_ptr, int expected_type) | |
479 | { | |
5260325f | 480 | int type; |
8efc0c15 | 481 | |
5260325f | 482 | type = packet_read(payload_len_ptr); |
483 | if (type != expected_type) | |
484 | packet_disconnect("Protocol error: expected packet type %d, got %d", | |
485 | expected_type, type); | |
8efc0c15 | 486 | } |
487 | ||
488 | /* Checks if a full packet is available in the data received so far via | |
5260325f | 489 | * packet_process_incoming. If so, reads the packet; otherwise returns |
490 | * SSH_MSG_NONE. This does not wait for data from the connection. | |
491 | * | |
492 | * SSH_MSG_DISCONNECT is handled specially here. Also, | |
493 | * SSH_MSG_IGNORE messages are skipped by this function and are never returned | |
494 | * to higher levels. | |
495 | * | |
496 | * The returned payload_len does include space consumed by: | |
497 | * Packet length | |
498 | * Padding | |
499 | * Packet type | |
500 | * Check bytes | |
501 | */ | |
8efc0c15 | 502 | |
503 | int | |
504 | packet_read_poll(int *payload_len_ptr) | |
505 | { | |
5260325f | 506 | unsigned int len, padded_len; |
507 | unsigned char *ucp; | |
508 | char buf[8], *cp; | |
509 | unsigned int checksum, stored_checksum; | |
510 | ||
511 | restart: | |
512 | ||
513 | /* Check if input size is less than minimum packet size. */ | |
514 | if (buffer_len(&input) < 4 + 8) | |
515 | return SSH_MSG_NONE; | |
516 | /* Get length of incoming packet. */ | |
517 | ucp = (unsigned char *) buffer_ptr(&input); | |
518 | len = GET_32BIT(ucp); | |
519 | if (len < 1 + 2 + 2 || len > 256 * 1024) | |
520 | packet_disconnect("Bad packet length %d.", len); | |
521 | padded_len = (len + 8) & ~7; | |
522 | ||
523 | /* Check if the packet has been entirely received. */ | |
524 | if (buffer_len(&input) < 4 + padded_len) | |
525 | return SSH_MSG_NONE; | |
526 | ||
527 | /* The entire packet is in buffer. */ | |
528 | ||
529 | /* Consume packet length. */ | |
530 | buffer_consume(&input, 4); | |
531 | ||
532 | /* Copy data to incoming_packet. */ | |
533 | buffer_clear(&incoming_packet); | |
534 | buffer_append_space(&incoming_packet, &cp, padded_len); | |
535 | packet_decrypt(&receive_context, cp, buffer_ptr(&input), padded_len); | |
536 | buffer_consume(&input, padded_len); | |
8efc0c15 | 537 | |
538 | #ifdef PACKET_DEBUG | |
5260325f | 539 | fprintf(stderr, "read_poll plain: "); |
540 | buffer_dump(&incoming_packet); | |
8efc0c15 | 541 | #endif |
5260325f | 542 | |
543 | /* Compute packet checksum. */ | |
544 | checksum = crc32((unsigned char *) buffer_ptr(&incoming_packet), | |
545 | buffer_len(&incoming_packet) - 4); | |
546 | ||
547 | /* Skip padding. */ | |
548 | buffer_consume(&incoming_packet, 8 - len % 8); | |
549 | ||
550 | /* Test check bytes. */ | |
551 | ||
552 | if (len != buffer_len(&incoming_packet)) | |
553 | packet_disconnect("packet_read_poll: len %d != buffer_len %d.", | |
554 | len, buffer_len(&incoming_packet)); | |
555 | ||
556 | ucp = (unsigned char *) buffer_ptr(&incoming_packet) + len - 4; | |
557 | stored_checksum = GET_32BIT(ucp); | |
558 | if (checksum != stored_checksum) | |
559 | packet_disconnect("Corrupted check bytes on input."); | |
560 | buffer_consume_end(&incoming_packet, 4); | |
561 | ||
562 | /* If using packet compression, decompress the packet. */ | |
563 | if (packet_compression) { | |
564 | buffer_clear(&compression_buffer); | |
565 | buffer_uncompress(&incoming_packet, &compression_buffer); | |
566 | buffer_clear(&incoming_packet); | |
567 | buffer_append(&incoming_packet, buffer_ptr(&compression_buffer), | |
568 | buffer_len(&compression_buffer)); | |
569 | } | |
570 | /* Get packet type. */ | |
571 | buffer_get(&incoming_packet, &buf[0], 1); | |
572 | ||
573 | /* Return length of payload (without type field). */ | |
574 | *payload_len_ptr = buffer_len(&incoming_packet); | |
575 | ||
576 | /* Handle disconnect message. */ | |
57112b5a | 577 | if ((unsigned char) buf[0] == SSH_MSG_DISCONNECT) { |
578 | log("Received disconnect: %.900s", packet_get_string(NULL)); | |
579 | fatal_cleanup(); | |
580 | } | |
5260325f | 581 | |
582 | /* Ignore ignore messages. */ | |
583 | if ((unsigned char) buf[0] == SSH_MSG_IGNORE) | |
584 | goto restart; | |
585 | ||
586 | /* Send debug messages as debugging output. */ | |
587 | if ((unsigned char) buf[0] == SSH_MSG_DEBUG) { | |
588 | debug("Remote: %.900s", packet_get_string(NULL)); | |
589 | goto restart; | |
590 | } | |
591 | /* Return type. */ | |
592 | return (unsigned char) buf[0]; | |
593 | } | |
594 | ||
aa3378df | 595 | /* |
596 | * Buffers the given amount of input characters. This is intended to be used | |
597 | * together with packet_read_poll. | |
598 | */ | |
8efc0c15 | 599 | |
600 | void | |
601 | packet_process_incoming(const char *buf, unsigned int len) | |
602 | { | |
5260325f | 603 | buffer_append(&input, buf, len); |
8efc0c15 | 604 | } |
605 | ||
606 | /* Returns a character from the packet. */ | |
607 | ||
608 | unsigned int | |
609 | packet_get_char() | |
610 | { | |
5260325f | 611 | char ch; |
612 | buffer_get(&incoming_packet, &ch, 1); | |
613 | return (unsigned char) ch; | |
8efc0c15 | 614 | } |
615 | ||
616 | /* Returns an integer from the packet data. */ | |
617 | ||
618 | unsigned int | |
619 | packet_get_int() | |
620 | { | |
5260325f | 621 | return buffer_get_int(&incoming_packet); |
8efc0c15 | 622 | } |
623 | ||
aa3378df | 624 | /* |
625 | * Returns an arbitrary precision integer from the packet data. The integer | |
626 | * must have been initialized before this call. | |
627 | */ | |
8efc0c15 | 628 | |
629 | void | |
5260325f | 630 | packet_get_bignum(BIGNUM * value, int *length_ptr) |
8efc0c15 | 631 | { |
5260325f | 632 | *length_ptr = buffer_get_bignum(&incoming_packet, value); |
8efc0c15 | 633 | } |
634 | ||
aa3378df | 635 | /* |
636 | * Returns a string from the packet data. The string is allocated using | |
637 | * xmalloc; it is the responsibility of the calling program to free it when | |
638 | * no longer needed. The length_ptr argument may be NULL, or point to an | |
639 | * integer into which the length of the string is stored. | |
640 | */ | |
8efc0c15 | 641 | |
aa3378df | 642 | char * |
5260325f | 643 | packet_get_string(unsigned int *length_ptr) |
8efc0c15 | 644 | { |
5260325f | 645 | return buffer_get_string(&incoming_packet, length_ptr); |
8efc0c15 | 646 | } |
647 | ||
aa3378df | 648 | /* |
649 | * Sends a diagnostic message from the server to the client. This message | |
650 | * can be sent at any time (but not while constructing another message). The | |
651 | * message is printed immediately, but only if the client is being executed | |
652 | * in verbose mode. These messages are primarily intended to ease debugging | |
653 | * authentication problems. The length of the formatted message must not | |
654 | * exceed 1024 bytes. This will automatically call packet_write_wait. | |
655 | */ | |
8efc0c15 | 656 | |
657 | void | |
5260325f | 658 | packet_send_debug(const char *fmt,...) |
8efc0c15 | 659 | { |
5260325f | 660 | char buf[1024]; |
661 | va_list args; | |
662 | ||
663 | va_start(args, fmt); | |
664 | vsnprintf(buf, sizeof(buf), fmt, args); | |
665 | va_end(args); | |
666 | ||
667 | packet_start(SSH_MSG_DEBUG); | |
668 | packet_put_string(buf, strlen(buf)); | |
669 | packet_send(); | |
670 | packet_write_wait(); | |
8efc0c15 | 671 | } |
672 | ||
aa3378df | 673 | /* |
674 | * Logs the error plus constructs and sends a disconnect packet, closes the | |
675 | * connection, and exits. This function never returns. The error message | |
676 | * should not contain a newline. The length of the formatted message must | |
677 | * not exceed 1024 bytes. | |
678 | */ | |
8efc0c15 | 679 | |
680 | void | |
5260325f | 681 | packet_disconnect(const char *fmt,...) |
682 | { | |
683 | char buf[1024]; | |
684 | va_list args; | |
685 | static int disconnecting = 0; | |
686 | if (disconnecting) /* Guard against recursive invocations. */ | |
687 | fatal("packet_disconnect called recursively."); | |
688 | disconnecting = 1; | |
689 | ||
aa3378df | 690 | /* |
691 | * Format the message. Note that the caller must make sure the | |
692 | * message is of limited size. | |
693 | */ | |
5260325f | 694 | va_start(args, fmt); |
695 | vsnprintf(buf, sizeof(buf), fmt, args); | |
696 | va_end(args); | |
697 | ||
698 | /* Send the disconnect message to the other side, and wait for it to get sent. */ | |
699 | packet_start(SSH_MSG_DISCONNECT); | |
700 | packet_put_string(buf, strlen(buf)); | |
701 | packet_send(); | |
702 | packet_write_wait(); | |
703 | ||
704 | /* Stop listening for connections. */ | |
705 | channel_stop_listening(); | |
706 | ||
707 | /* Close the connection. */ | |
708 | packet_close(); | |
709 | ||
710 | /* Display the error locally and exit. */ | |
57112b5a | 711 | log("Disconnecting: %.100s", buf); |
712 | fatal_cleanup(); | |
8efc0c15 | 713 | } |
714 | ||
aa3378df | 715 | /* Checks if there is any buffered output, and tries to write some of the output. */ |
8efc0c15 | 716 | |
717 | void | |
718 | packet_write_poll() | |
719 | { | |
5260325f | 720 | int len = buffer_len(&output); |
721 | if (len > 0) { | |
722 | len = write(connection_out, buffer_ptr(&output), len); | |
723 | if (len <= 0) { | |
724 | if (errno == EAGAIN) | |
725 | return; | |
726 | else | |
727 | fatal("Write failed: %.100s", strerror(errno)); | |
728 | } | |
729 | buffer_consume(&output, len); | |
730 | } | |
8efc0c15 | 731 | } |
732 | ||
aa3378df | 733 | /* |
734 | * Calls packet_write_poll repeatedly until all pending output data has been | |
735 | * written. | |
736 | */ | |
8efc0c15 | 737 | |
738 | void | |
739 | packet_write_wait() | |
740 | { | |
5260325f | 741 | packet_write_poll(); |
742 | while (packet_have_data_to_write()) { | |
743 | fd_set set; | |
744 | FD_ZERO(&set); | |
745 | FD_SET(connection_out, &set); | |
746 | select(connection_out + 1, NULL, &set, NULL, NULL); | |
747 | packet_write_poll(); | |
748 | } | |
8efc0c15 | 749 | } |
750 | ||
751 | /* Returns true if there is buffered data to write to the connection. */ | |
752 | ||
753 | int | |
754 | packet_have_data_to_write() | |
755 | { | |
5260325f | 756 | return buffer_len(&output) != 0; |
8efc0c15 | 757 | } |
758 | ||
759 | /* Returns true if there is not too much data to write to the connection. */ | |
760 | ||
761 | int | |
762 | packet_not_very_much_data_to_write() | |
763 | { | |
5260325f | 764 | if (interactive_mode) |
765 | return buffer_len(&output) < 16384; | |
766 | else | |
767 | return buffer_len(&output) < 128 * 1024; | |
8efc0c15 | 768 | } |
769 | ||
770 | /* Informs that the current session is interactive. Sets IP flags for that. */ | |
771 | ||
772 | void | |
773 | packet_set_interactive(int interactive, int keepalives) | |
774 | { | |
5260325f | 775 | int on = 1; |
776 | ||
777 | /* Record that we are in interactive mode. */ | |
778 | interactive_mode = interactive; | |
779 | ||
48e671d5 | 780 | /* Only set socket options if using a socket. */ |
781 | if (!packet_connection_is_on_socket()) | |
5260325f | 782 | return; |
5260325f | 783 | if (keepalives) { |
784 | /* Set keepalives if requested. */ | |
785 | if (setsockopt(connection_in, SOL_SOCKET, SO_KEEPALIVE, (void *) &on, | |
48e671d5 | 786 | sizeof(on)) < 0) |
5260325f | 787 | error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); |
788 | } | |
48e671d5 | 789 | /* |
790 | * IPTOS_LOWDELAY, TCP_NODELAY and IPTOS_THROUGHPUT are IPv4 only | |
791 | */ | |
792 | if (!packet_connection_is_ipv4()) | |
793 | return; | |
5260325f | 794 | if (interactive) { |
aa3378df | 795 | /* |
796 | * Set IP options for an interactive connection. Use | |
797 | * IPTOS_LOWDELAY and TCP_NODELAY. | |
798 | */ | |
5260325f | 799 | int lowdelay = IPTOS_LOWDELAY; |
800 | if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, (void *) &lowdelay, | |
48e671d5 | 801 | sizeof(lowdelay)) < 0) |
5260325f | 802 | error("setsockopt IPTOS_LOWDELAY: %.100s", strerror(errno)); |
803 | if (setsockopt(connection_in, IPPROTO_TCP, TCP_NODELAY, (void *) &on, | |
48e671d5 | 804 | sizeof(on)) < 0) |
5260325f | 805 | error("setsockopt TCP_NODELAY: %.100s", strerror(errno)); |
806 | } else { | |
aa3378df | 807 | /* |
808 | * Set IP options for a non-interactive connection. Use | |
809 | * IPTOS_THROUGHPUT. | |
810 | */ | |
5260325f | 811 | int throughput = IPTOS_THROUGHPUT; |
812 | if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, (void *) &throughput, | |
48e671d5 | 813 | sizeof(throughput)) < 0) |
5260325f | 814 | error("setsockopt IPTOS_THROUGHPUT: %.100s", strerror(errno)); |
815 | } | |
8efc0c15 | 816 | } |
817 | ||
818 | /* Returns true if the current connection is interactive. */ | |
819 | ||
820 | int | |
821 | packet_is_interactive() | |
822 | { | |
5260325f | 823 | return interactive_mode; |
8efc0c15 | 824 | } |
9d6b7add | 825 | |
826 | int | |
827 | packet_set_maxsize(int s) | |
828 | { | |
5260325f | 829 | static int called = 0; |
830 | if (called) { | |
831 | log("packet_set_maxsize: called twice: old %d new %d", max_packet_size, s); | |
832 | return -1; | |
833 | } | |
834 | if (s < 4 * 1024 || s > 1024 * 1024) { | |
835 | log("packet_set_maxsize: bad size %d", s); | |
836 | return -1; | |
837 | } | |
838 | log("packet_set_maxsize: setting to %d", s); | |
839 | max_packet_size = s; | |
840 | return s; | |
9d6b7add | 841 | } |