Annotation of src/usr.bin/ssh/packet.c, Revision 1.114
1.1 deraadt 1: /*
1.15 deraadt 2: * Author: Tatu Ylonen <ylo@cs.hut.fi>
3: * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
4: * All rights reserved
1.35 deraadt 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.
1.29 markus 7: *
1.35 deraadt 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".
1.29 markus 13: *
1.25 markus 14: *
15: * SSH2 packet format added by Markus Friedl.
1.69 markus 16: * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
1.25 markus 17: *
1.35 deraadt 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.
26: *
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.
1.15 deraadt 37: */
1.1 deraadt 38:
39: #include "includes.h"
1.114 ! djm 40: RCSID("$OpenBSD: packet.c,v 1.113 2004/05/11 19:01:43 deraadt Exp $");
1.105 markus 41:
42: #include <sys/queue.h>
1.1 deraadt 43:
44: #include "xmalloc.h"
45: #include "buffer.h"
46: #include "packet.h"
47: #include "bufaux.h"
48: #include "crc32.h"
49: #include "getput.h"
50:
51: #include "compress.h"
1.9 dugsong 52: #include "deattack.h"
1.64 markus 53: #include "channels.h"
1.1 deraadt 54:
1.25 markus 55: #include "compat.h"
1.45 markus 56: #include "ssh1.h"
1.25 markus 57: #include "ssh2.h"
58:
1.37 markus 59: #include "cipher.h"
1.25 markus 60: #include "kex.h"
1.50 markus 61: #include "mac.h"
1.46 markus 62: #include "log.h"
63: #include "canohost.h"
1.87 stevesk 64: #include "misc.h"
1.95 markus 65: #include "ssh.h"
1.25 markus 66:
67: #ifdef PACKET_DEBUG
68: #define DBG(x) x
69: #else
70: #define DBG(x)
71: #endif
72:
1.16 markus 73: /*
74: * This variable contains the file descriptors used for communicating with
75: * the other side. connection_in is used for reading; connection_out for
76: * writing. These can be the same descriptor, in which case it is assumed to
77: * be a socket.
78: */
1.1 deraadt 79: static int connection_in = -1;
80: static int connection_out = -1;
81:
82: /* Protocol flags for the remote side. */
1.40 markus 83: static u_int remote_protocol_flags = 0;
1.1 deraadt 84:
85: /* Encryption context for receiving data. This is only used for decryption. */
86: static CipherContext receive_context;
1.14 markus 87:
88: /* Encryption context for sending data. This is only used for encryption. */
1.1 deraadt 89: static CipherContext send_context;
90:
91: /* Buffer for raw input data from the socket. */
1.91 markus 92: Buffer input;
1.1 deraadt 93:
94: /* Buffer for raw output data going to the socket. */
1.91 markus 95: Buffer output;
1.1 deraadt 96:
97: /* Buffer for the partial outgoing packet being constructed. */
98: static Buffer outgoing_packet;
99:
100: /* Buffer for the incoming packet currently being processed. */
101: static Buffer incoming_packet;
102:
103: /* Scratch buffer for packet compression/decompression. */
104: static Buffer compression_buffer;
1.60 markus 105: static int compression_buffer_ready = 0;
1.1 deraadt 106:
107: /* Flag indicating whether packet compression/decompression is enabled. */
108: static int packet_compression = 0;
109:
1.12 markus 110: /* default maximum packet size */
1.108 markus 111: u_int max_packet_size = 32768;
1.12 markus 112:
1.1 deraadt 113: /* Flag indicating whether this module has been initialized. */
114: static int initialized = 0;
115:
116: /* Set to true if the connection is interactive. */
117: static int interactive_mode = 0;
118:
1.25 markus 119: /* Session key information for Encryption and MAC */
1.57 markus 120: Newkeys *newkeys[MODE_MAX];
1.105 markus 121: static struct packet_state {
122: u_int32_t seqnr;
123: u_int32_t packets;
124: u_int64_t blocks;
125: } p_read, p_send;
126:
127: static u_int64_t max_blocks_in, max_blocks_out;
128: static u_int32_t rekey_limit;
1.25 markus 129:
1.95 markus 130: /* Session key for protocol v1 */
131: static u_char ssh1_key[SSH_SESSION_KEY_LENGTH];
132: static u_int ssh1_keylen;
133:
1.71 markus 134: /* roundup current message to extra_pad bytes */
135: static u_char extra_pad = 0;
136:
1.105 markus 137: struct packet {
138: TAILQ_ENTRY(packet) next;
139: u_char type;
140: Buffer payload;
141: };
142: TAILQ_HEAD(, packet) outgoing;
143:
1.16 markus 144: /*
145: * Sets the descriptors used for communication. Disables encryption until
146: * packet_set_encryption_key is called.
147: */
1.2 provos 148: void
149: packet_set_connection(int fd_in, int fd_out)
1.1 deraadt 150: {
1.37 markus 151: Cipher *none = cipher_by_name("none");
1.97 deraadt 152:
1.37 markus 153: if (none == NULL)
154: fatal("packet_set_connection: cannot load cipher 'none'");
1.14 markus 155: connection_in = fd_in;
156: connection_out = fd_out;
1.113 deraadt 157: cipher_init(&send_context, none, (const u_char *)"",
158: 0, NULL, 0, CIPHER_ENCRYPT);
159: cipher_init(&receive_context, none, (const u_char *)"",
160: 0, NULL, 0, CIPHER_DECRYPT);
1.62 markus 161: newkeys[MODE_IN] = newkeys[MODE_OUT] = NULL;
1.14 markus 162: if (!initialized) {
163: initialized = 1;
164: buffer_init(&input);
165: buffer_init(&output);
166: buffer_init(&outgoing_packet);
167: buffer_init(&incoming_packet);
1.105 markus 168: TAILQ_INIT(&outgoing);
1.14 markus 169: }
1.1 deraadt 170: }
171:
1.19 markus 172: /* Returns 1 if remote host is connected via socket, 0 if not. */
173:
174: int
1.73 itojun 175: packet_connection_is_on_socket(void)
1.19 markus 176: {
177: struct sockaddr_storage from, to;
178: socklen_t fromlen, tolen;
179:
180: /* filedescriptors in and out are the same, so it's a socket */
181: if (connection_in == connection_out)
182: return 1;
183: fromlen = sizeof(from);
184: memset(&from, 0, sizeof(from));
1.20 markus 185: if (getpeername(connection_in, (struct sockaddr *)&from, &fromlen) < 0)
1.19 markus 186: return 0;
187: tolen = sizeof(to);
188: memset(&to, 0, sizeof(to));
1.20 markus 189: if (getpeername(connection_out, (struct sockaddr *)&to, &tolen) < 0)
1.19 markus 190: return 0;
191: if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0)
192: return 0;
193: if (from.ss_family != AF_INET && from.ss_family != AF_INET6)
194: return 0;
195: return 1;
196: }
197:
1.92 markus 198: /*
1.91 markus 199: * Exports an IV from the CipherContext required to export the key
200: * state back from the unprivileged child to the privileged parent
201: * process.
202: */
203:
204: void
205: packet_get_keyiv(int mode, u_char *iv, u_int len)
206: {
207: CipherContext *cc;
208:
209: if (mode == MODE_OUT)
210: cc = &send_context;
211: else
212: cc = &receive_context;
213:
214: cipher_get_keyiv(cc, iv, len);
215: }
216:
217: int
218: packet_get_keycontext(int mode, u_char *dat)
219: {
220: CipherContext *cc;
1.92 markus 221:
1.91 markus 222: if (mode == MODE_OUT)
223: cc = &send_context;
224: else
225: cc = &receive_context;
226:
227: return (cipher_get_keycontext(cc, dat));
228: }
229:
230: void
231: packet_set_keycontext(int mode, u_char *dat)
232: {
233: CipherContext *cc;
1.92 markus 234:
1.91 markus 235: if (mode == MODE_OUT)
236: cc = &send_context;
237: else
238: cc = &receive_context;
239:
240: cipher_set_keycontext(cc, dat);
241: }
242:
243: int
244: packet_get_keyiv_len(int mode)
245: {
246: CipherContext *cc;
247:
248: if (mode == MODE_OUT)
249: cc = &send_context;
250: else
251: cc = &receive_context;
252:
253: return (cipher_get_keyiv_len(cc));
254: }
255: void
256: packet_set_iv(int mode, u_char *dat)
257: {
258: CipherContext *cc;
259:
260: if (mode == MODE_OUT)
261: cc = &send_context;
262: else
263: cc = &receive_context;
264:
265: cipher_set_keyiv(cc, dat);
266: }
267: int
1.107 deraadt 268: packet_get_ssh1_cipher(void)
1.91 markus 269: {
270: return (cipher_get_number(receive_context.cipher));
271: }
272:
1.105 markus 273: void
274: packet_get_state(int mode, u_int32_t *seqnr, u_int64_t *blocks, u_int32_t *packets)
275: {
276: struct packet_state *state;
1.104 markus 277:
1.105 markus 278: state = (mode == MODE_IN) ? &p_read : &p_send;
279: *seqnr = state->seqnr;
280: *blocks = state->blocks;
281: *packets = state->packets;
1.91 markus 282: }
283:
284: void
1.105 markus 285: packet_set_state(int mode, u_int32_t seqnr, u_int64_t blocks, u_int32_t packets)
1.91 markus 286: {
1.105 markus 287: struct packet_state *state;
288:
289: state = (mode == MODE_IN) ? &p_read : &p_send;
290: state->seqnr = seqnr;
291: state->blocks = blocks;
292: state->packets = packets;
1.91 markus 293: }
294:
1.19 markus 295: /* returns 1 if connection is via ipv4 */
296:
297: int
1.73 itojun 298: packet_connection_is_ipv4(void)
1.19 markus 299: {
300: struct sockaddr_storage to;
1.21 deraadt 301: socklen_t tolen = sizeof(to);
1.19 markus 302:
303: memset(&to, 0, sizeof(to));
304: if (getsockname(connection_out, (struct sockaddr *)&to, &tolen) < 0)
305: return 0;
306: if (to.ss_family != AF_INET)
307: return 0;
308: return 1;
309: }
310:
1.1 deraadt 311: /* Sets the connection into non-blocking mode. */
312:
1.2 provos 313: void
1.73 itojun 314: packet_set_nonblocking(void)
1.1 deraadt 315: {
1.14 markus 316: /* Set the socket into non-blocking mode. */
1.114 ! djm 317: set_nonblock(connection_in);
1.14 markus 318:
1.114 ! djm 319: if (connection_out != connection_in)
! 320: set_nonblock(connection_out);
1.1 deraadt 321: }
322:
323: /* Returns the socket used for reading. */
324:
1.2 provos 325: int
1.73 itojun 326: packet_get_connection_in(void)
1.1 deraadt 327: {
1.14 markus 328: return connection_in;
1.1 deraadt 329: }
330:
331: /* Returns the descriptor used for writing. */
332:
1.2 provos 333: int
1.73 itojun 334: packet_get_connection_out(void)
1.1 deraadt 335: {
1.14 markus 336: return connection_out;
1.1 deraadt 337: }
338:
339: /* Closes the connection and clears and frees internal data structures. */
340:
1.2 provos 341: void
1.73 itojun 342: packet_close(void)
1.1 deraadt 343: {
1.14 markus 344: if (!initialized)
345: return;
346: initialized = 0;
347: if (connection_in == connection_out) {
348: shutdown(connection_out, SHUT_RDWR);
349: close(connection_out);
350: } else {
351: close(connection_in);
352: close(connection_out);
353: }
354: buffer_free(&input);
355: buffer_free(&output);
356: buffer_free(&outgoing_packet);
357: buffer_free(&incoming_packet);
1.60 markus 358: if (compression_buffer_ready) {
1.14 markus 359: buffer_free(&compression_buffer);
360: buffer_compress_uninit();
361: }
1.88 markus 362: cipher_cleanup(&send_context);
363: cipher_cleanup(&receive_context);
1.1 deraadt 364: }
365:
366: /* Sets remote side protocol flags. */
367:
1.2 provos 368: void
1.40 markus 369: packet_set_protocol_flags(u_int protocol_flags)
1.1 deraadt 370: {
1.14 markus 371: remote_protocol_flags = protocol_flags;
1.1 deraadt 372: }
373:
374: /* Returns the remote protocol flags set earlier by the above function. */
375:
1.40 markus 376: u_int
1.73 itojun 377: packet_get_protocol_flags(void)
1.1 deraadt 378: {
1.14 markus 379: return remote_protocol_flags;
1.1 deraadt 380: }
381:
1.16 markus 382: /*
383: * Starts packet compression from the next packet on in both directions.
384: * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip.
385: */
1.1 deraadt 386:
1.68 itojun 387: static void
388: packet_init_compression(void)
1.60 markus 389: {
390: if (compression_buffer_ready == 1)
391: return;
392: compression_buffer_ready = 1;
393: buffer_init(&compression_buffer);
394: }
395:
1.2 provos 396: void
397: packet_start_compression(int level)
1.1 deraadt 398: {
1.62 markus 399: if (packet_compression && !compat20)
1.14 markus 400: fatal("Compression already enabled.");
401: packet_compression = 1;
1.60 markus 402: packet_init_compression();
403: buffer_compress_init_send(level);
404: buffer_compress_init_recv();
1.1 deraadt 405: }
406:
1.16 markus 407: /*
408: * Causes any further packets to be encrypted using the given key. The same
409: * key is used for both sending and reception. However, both directions are
410: * encrypted independently of each other.
411: */
1.95 markus 412:
1.2 provos 413: void
1.40 markus 414: packet_set_encryption_key(const u_char *key, u_int keylen,
1.37 markus 415: int number)
1.1 deraadt 416: {
1.37 markus 417: Cipher *cipher = cipher_by_number(number);
1.97 deraadt 418:
1.37 markus 419: if (cipher == NULL)
420: fatal("packet_set_encryption_key: unknown cipher number %d", number);
1.25 markus 421: if (keylen < 20)
1.37 markus 422: fatal("packet_set_encryption_key: keylen too small: %d", keylen);
1.95 markus 423: if (keylen > SSH_SESSION_KEY_LENGTH)
424: fatal("packet_set_encryption_key: keylen too big: %d", keylen);
425: memcpy(ssh1_key, key, keylen);
426: ssh1_keylen = keylen;
1.88 markus 427: cipher_init(&send_context, cipher, key, keylen, NULL, 0, CIPHER_ENCRYPT);
428: cipher_init(&receive_context, cipher, key, keylen, NULL, 0, CIPHER_DECRYPT);
1.95 markus 429: }
430:
431: u_int
432: packet_get_encryption_key(u_char *key)
433: {
434: if (key == NULL)
435: return (ssh1_keylen);
436: memcpy(key, ssh1_key, ssh1_keylen);
437: return (ssh1_keylen);
1.1 deraadt 438: }
439:
1.62 markus 440: /* Start constructing a packet to send. */
1.2 provos 441: void
1.62 markus 442: packet_start(u_char type)
1.1 deraadt 443: {
1.62 markus 444: u_char buf[9];
445: int len;
1.1 deraadt 446:
1.62 markus 447: DBG(debug("packet_start[%d]", type));
448: len = compat20 ? 6 : 9;
449: memset(buf, 0, len - 1);
450: buf[len - 1] = type;
1.14 markus 451: buffer_clear(&outgoing_packet);
1.62 markus 452: buffer_append(&outgoing_packet, buf, len);
1.25 markus 453: }
454:
1.62 markus 455: /* Append payload. */
1.2 provos 456: void
457: packet_put_char(int value)
1.1 deraadt 458: {
1.14 markus 459: char ch = value;
1.97 deraadt 460:
1.14 markus 461: buffer_append(&outgoing_packet, &ch, 1);
1.1 deraadt 462: }
1.2 provos 463: void
1.40 markus 464: packet_put_int(u_int value)
1.1 deraadt 465: {
1.14 markus 466: buffer_put_int(&outgoing_packet, value);
1.1 deraadt 467: }
1.2 provos 468: void
1.76 stevesk 469: packet_put_string(const void *buf, u_int len)
1.1 deraadt 470: {
1.14 markus 471: buffer_put_string(&outgoing_packet, buf, len);
1.1 deraadt 472: }
1.24 markus 473: void
474: packet_put_cstring(const char *str)
475: {
1.65 markus 476: buffer_put_cstring(&outgoing_packet, str);
1.24 markus 477: }
478: void
1.76 stevesk 479: packet_put_raw(const void *buf, u_int len)
1.24 markus 480: {
481: buffer_append(&outgoing_packet, buf, len);
482: }
1.2 provos 483: void
1.14 markus 484: packet_put_bignum(BIGNUM * value)
1.1 deraadt 485: {
1.14 markus 486: buffer_put_bignum(&outgoing_packet, value);
1.1 deraadt 487: }
1.24 markus 488: void
489: packet_put_bignum2(BIGNUM * value)
490: {
491: buffer_put_bignum2(&outgoing_packet, value);
492: }
1.1 deraadt 493:
1.16 markus 494: /*
495: * Finalizes and sends the packet. If the encryption key has been set,
496: * encrypts the packet before sending.
497: */
1.14 markus 498:
1.68 itojun 499: static void
1.49 itojun 500: packet_send1(void)
1.1 deraadt 501: {
1.89 markus 502: u_char buf[8], *cp;
1.14 markus 503: int i, padding, len;
1.40 markus 504: u_int checksum;
1.14 markus 505: u_int32_t rand = 0;
506:
1.16 markus 507: /*
508: * If using packet compression, compress the payload of the outgoing
509: * packet.
510: */
1.14 markus 511: if (packet_compression) {
512: buffer_clear(&compression_buffer);
513: /* Skip padding. */
514: buffer_consume(&outgoing_packet, 8);
515: /* padding */
516: buffer_append(&compression_buffer, "\0\0\0\0\0\0\0\0", 8);
517: buffer_compress(&outgoing_packet, &compression_buffer);
518: buffer_clear(&outgoing_packet);
519: buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer),
1.75 deraadt 520: buffer_len(&compression_buffer));
1.14 markus 521: }
522: /* Compute packet length without padding (add checksum, remove padding). */
523: len = buffer_len(&outgoing_packet) + 4 - 8;
524:
1.32 markus 525: /* Insert padding. Initialized to zero in packet_start1() */
1.14 markus 526: padding = 8 - len % 8;
1.88 markus 527: if (!send_context.plaintext) {
1.14 markus 528: cp = buffer_ptr(&outgoing_packet);
529: for (i = 0; i < padding; i++) {
530: if (i % 4 == 0)
531: rand = arc4random();
532: cp[7 - i] = rand & 0xff;
533: rand >>= 8;
534: }
535: }
536: buffer_consume(&outgoing_packet, 8 - padding);
537:
538: /* Add check bytes. */
1.83 stevesk 539: checksum = ssh_crc32(buffer_ptr(&outgoing_packet),
1.34 deraadt 540: buffer_len(&outgoing_packet));
1.14 markus 541: PUT_32BIT(buf, checksum);
542: buffer_append(&outgoing_packet, buf, 4);
1.1 deraadt 543:
544: #ifdef PACKET_DEBUG
1.14 markus 545: fprintf(stderr, "packet_send plain: ");
546: buffer_dump(&outgoing_packet);
1.1 deraadt 547: #endif
548:
1.14 markus 549: /* Append to output. */
550: PUT_32BIT(buf, len);
551: buffer_append(&output, buf, 4);
1.76 stevesk 552: cp = buffer_append_space(&output, buffer_len(&outgoing_packet));
1.88 markus 553: cipher_crypt(&send_context, cp, buffer_ptr(&outgoing_packet),
1.75 deraadt 554: buffer_len(&outgoing_packet));
1.14 markus 555:
1.1 deraadt 556: #ifdef PACKET_DEBUG
1.14 markus 557: fprintf(stderr, "encrypted: ");
558: buffer_dump(&output);
1.1 deraadt 559: #endif
560:
1.14 markus 561: buffer_clear(&outgoing_packet);
1.1 deraadt 562:
1.16 markus 563: /*
564: * Note that the packet is now only buffered in output. It won\'t be
565: * actually sent until packet_write_wait or packet_write_poll is
566: * called.
567: */
1.1 deraadt 568: }
569:
1.91 markus 570: void
1.57 markus 571: set_newkeys(int mode)
572: {
573: Enc *enc;
574: Mac *mac;
575: Comp *comp;
576: CipherContext *cc;
1.105 markus 577: u_int64_t *max_blocks;
1.88 markus 578: int encrypt;
1.57 markus 579:
1.100 markus 580: debug2("set_newkeys: mode %d", mode);
1.57 markus 581:
1.88 markus 582: if (mode == MODE_OUT) {
583: cc = &send_context;
584: encrypt = CIPHER_ENCRYPT;
1.105 markus 585: p_send.packets = p_send.blocks = 0;
586: max_blocks = &max_blocks_out;
1.88 markus 587: } else {
588: cc = &receive_context;
589: encrypt = CIPHER_DECRYPT;
1.105 markus 590: p_read.packets = p_read.blocks = 0;
591: max_blocks = &max_blocks_in;
1.88 markus 592: }
1.57 markus 593: if (newkeys[mode] != NULL) {
1.100 markus 594: debug("set_newkeys: rekeying");
1.88 markus 595: cipher_cleanup(cc);
1.59 markus 596: enc = &newkeys[mode]->enc;
597: mac = &newkeys[mode]->mac;
598: comp = &newkeys[mode]->comp;
1.61 markus 599: memset(mac->key, 0, mac->key_len);
1.59 markus 600: xfree(enc->name);
601: xfree(enc->iv);
602: xfree(enc->key);
603: xfree(mac->name);
604: xfree(mac->key);
605: xfree(comp->name);
1.58 markus 606: xfree(newkeys[mode]);
1.57 markus 607: }
608: newkeys[mode] = kex_get_newkeys(mode);
609: if (newkeys[mode] == NULL)
610: fatal("newkeys: no keys for mode %d", mode);
611: enc = &newkeys[mode]->enc;
612: mac = &newkeys[mode]->mac;
613: comp = &newkeys[mode]->comp;
614: if (mac->md != NULL)
615: mac->enabled = 1;
616: DBG(debug("cipher_init_context: %d", mode));
1.88 markus 617: cipher_init(cc, enc->cipher, enc->key, enc->key_len,
618: enc->iv, enc->block_size, encrypt);
1.91 markus 619: /* Deleting the keys does not gain extra security */
620: /* memset(enc->iv, 0, enc->block_size);
621: memset(enc->key, 0, enc->key_len); */
1.57 markus 622: if (comp->type != 0 && comp->enabled == 0) {
1.60 markus 623: packet_init_compression();
624: if (mode == MODE_OUT)
625: buffer_compress_init_send(6);
626: else
627: buffer_compress_init_recv();
1.57 markus 628: comp->enabled = 1;
629: }
1.109 markus 630: /*
631: * The 2^(blocksize*2) limit is too expensive for 3DES,
632: * blowfish, etc, so enforce a 1GB limit for small blocksizes.
633: */
634: if (enc->block_size >= 16)
635: *max_blocks = (u_int64_t)1 << (enc->block_size*2);
636: else
637: *max_blocks = ((u_int64_t)1 << 30) / enc->block_size;
1.105 markus 638: if (rekey_limit)
639: *max_blocks = MIN(*max_blocks, rekey_limit / enc->block_size);
1.57 markus 640: }
641:
1.16 markus 642: /*
1.25 markus 643: * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue)
644: */
1.68 itojun 645: static void
1.105 markus 646: packet_send2_wrapped(void)
1.25 markus 647: {
1.89 markus 648: u_char type, *cp, *macbuf = NULL;
1.71 markus 649: u_char padlen, pad;
1.40 markus 650: u_int packet_length = 0;
1.71 markus 651: u_int i, len;
1.25 markus 652: u_int32_t rand = 0;
653: Enc *enc = NULL;
654: Mac *mac = NULL;
655: Comp *comp = NULL;
656: int block_size;
657:
1.57 markus 658: if (newkeys[MODE_OUT] != NULL) {
659: enc = &newkeys[MODE_OUT]->enc;
660: mac = &newkeys[MODE_OUT]->mac;
661: comp = &newkeys[MODE_OUT]->comp;
1.25 markus 662: }
1.88 markus 663: block_size = enc ? enc->block_size : 8;
1.25 markus 664:
1.89 markus 665: cp = buffer_ptr(&outgoing_packet);
666: type = cp[5];
1.25 markus 667:
668: #ifdef PACKET_DEBUG
669: fprintf(stderr, "plain: ");
670: buffer_dump(&outgoing_packet);
671: #endif
672:
673: if (comp && comp->enabled) {
674: len = buffer_len(&outgoing_packet);
675: /* skip header, compress only payload */
676: buffer_consume(&outgoing_packet, 5);
677: buffer_clear(&compression_buffer);
678: buffer_compress(&outgoing_packet, &compression_buffer);
679: buffer_clear(&outgoing_packet);
680: buffer_append(&outgoing_packet, "\0\0\0\0\0", 5);
681: buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer),
682: buffer_len(&compression_buffer));
683: DBG(debug("compression: raw %d compressed %d", len,
684: buffer_len(&outgoing_packet)));
685: }
686:
687: /* sizeof (packet_len + pad_len + payload) */
688: len = buffer_len(&outgoing_packet);
689:
690: /*
691: * calc size of padding, alloc space, get random data,
692: * minimum padding is 4 bytes
693: */
694: padlen = block_size - (len % block_size);
695: if (padlen < 4)
696: padlen += block_size;
1.71 markus 697: if (extra_pad) {
698: /* will wrap if extra_pad+padlen > 255 */
699: extra_pad = roundup(extra_pad, block_size);
700: pad = extra_pad - ((len + padlen) % extra_pad);
1.93 markus 701: debug3("packet_send2: adding %d (len %d padlen %d extra_pad %d)",
1.71 markus 702: pad, len, padlen, extra_pad);
703: padlen += pad;
704: extra_pad = 0;
705: }
1.76 stevesk 706: cp = buffer_append_space(&outgoing_packet, padlen);
1.88 markus 707: if (enc && !send_context.plaintext) {
1.32 markus 708: /* random padding */
1.25 markus 709: for (i = 0; i < padlen; i++) {
710: if (i % 4 == 0)
711: rand = arc4random();
712: cp[i] = rand & 0xff;
1.52 markus 713: rand >>= 8;
1.25 markus 714: }
1.32 markus 715: } else {
716: /* clear padding */
717: memset(cp, 0, padlen);
1.25 markus 718: }
719: /* packet_length includes payload, padding and padding length field */
720: packet_length = buffer_len(&outgoing_packet) - 4;
1.89 markus 721: cp = buffer_ptr(&outgoing_packet);
722: PUT_32BIT(cp, packet_length);
723: cp[4] = padlen;
1.25 markus 724: DBG(debug("send: len %d (includes padlen %d)", packet_length+4, padlen));
725:
726: /* compute MAC over seqnr and packet(length fields, payload, padding) */
727: if (mac && mac->enabled) {
1.105 markus 728: macbuf = mac_compute(mac, p_send.seqnr,
1.83 stevesk 729: buffer_ptr(&outgoing_packet),
1.50 markus 730: buffer_len(&outgoing_packet));
1.105 markus 731: DBG(debug("done calc MAC out #%d", p_send.seqnr));
1.25 markus 732: }
733: /* encrypt packet and append to output buffer. */
1.76 stevesk 734: cp = buffer_append_space(&output, buffer_len(&outgoing_packet));
1.88 markus 735: cipher_crypt(&send_context, cp, buffer_ptr(&outgoing_packet),
1.25 markus 736: buffer_len(&outgoing_packet));
737: /* append unencrypted MAC */
738: if (mac && mac->enabled)
739: buffer_append(&output, (char *)macbuf, mac->mac_len);
740: #ifdef PACKET_DEBUG
741: fprintf(stderr, "encrypted: ");
742: buffer_dump(&output);
743: #endif
1.29 markus 744: /* increment sequence number for outgoing packets */
1.105 markus 745: if (++p_send.seqnr == 0)
1.106 itojun 746: logit("outgoing seqnr wraps around");
1.105 markus 747: if (++p_send.packets == 0)
748: if (!(datafellows & SSH_BUG_NOREKEY))
749: fatal("XXX too many packets with same key");
750: p_send.blocks += (packet_length + 4) / block_size;
1.25 markus 751: buffer_clear(&outgoing_packet);
752:
1.57 markus 753: if (type == SSH2_MSG_NEWKEYS)
754: set_newkeys(MODE_OUT);
1.25 markus 755: }
756:
1.105 markus 757: static void
758: packet_send2(void)
759: {
760: static int rekeying = 0;
761: struct packet *p;
762: u_char type, *cp;
763:
764: cp = buffer_ptr(&outgoing_packet);
765: type = cp[5];
766:
767: /* during rekeying we can only send key exchange messages */
768: if (rekeying) {
769: if (!((type >= SSH2_MSG_TRANSPORT_MIN) &&
770: (type <= SSH2_MSG_TRANSPORT_MAX))) {
771: debug("enqueue packet: %u", type);
772: p = xmalloc(sizeof(*p));
773: p->type = type;
774: memcpy(&p->payload, &outgoing_packet, sizeof(Buffer));
775: buffer_init(&outgoing_packet);
776: TAILQ_INSERT_TAIL(&outgoing, p, next);
777: return;
778: }
779: }
780:
781: /* rekeying starts with sending KEXINIT */
782: if (type == SSH2_MSG_KEXINIT)
783: rekeying = 1;
784:
785: packet_send2_wrapped();
786:
787: /* after a NEWKEYS message we can send the complete queue */
788: if (type == SSH2_MSG_NEWKEYS) {
789: rekeying = 0;
790: while ((p = TAILQ_FIRST(&outgoing))) {
791: type = p->type;
792: debug("dequeue packet: %u", type);
793: buffer_free(&outgoing_packet);
794: memcpy(&outgoing_packet, &p->payload,
795: sizeof(Buffer));
796: TAILQ_REMOVE(&outgoing, p, next);
797: xfree(p);
798: packet_send2_wrapped();
799: }
800: }
801: }
802:
1.25 markus 803: void
1.73 itojun 804: packet_send(void)
1.25 markus 805: {
1.62 markus 806: if (compat20)
1.25 markus 807: packet_send2();
808: else
809: packet_send1();
810: DBG(debug("packet_send done"));
811: }
812:
813: /*
1.16 markus 814: * Waits until a packet has been received, and returns its type. Note that
815: * no other data is processed until this returns, so this function should not
816: * be used during the interactive session.
817: */
1.1 deraadt 818:
1.2 provos 819: int
1.82 markus 820: packet_read_seqnr(u_int32_t *seqnr_p)
1.1 deraadt 821: {
1.14 markus 822: int type, len;
1.56 millert 823: fd_set *setp;
1.14 markus 824: char buf[8192];
1.25 markus 825: DBG(debug("packet_read()"));
1.14 markus 826:
1.56 millert 827: setp = (fd_set *)xmalloc(howmany(connection_in+1, NFDBITS) *
828: sizeof(fd_mask));
829:
1.14 markus 830: /* Since we are blocking, ensure that all written packets have been sent. */
831: packet_write_wait();
832:
833: /* Stay in the loop until we have received a complete packet. */
834: for (;;) {
835: /* Try to read a packet from the buffer. */
1.82 markus 836: type = packet_read_poll_seqnr(seqnr_p);
1.62 markus 837: if (!compat20 && (
1.32 markus 838: type == SSH_SMSG_SUCCESS
1.14 markus 839: || type == SSH_SMSG_FAILURE
840: || type == SSH_CMSG_EOF
1.32 markus 841: || type == SSH_CMSG_EXIT_CONFIRMATION))
1.79 markus 842: packet_check_eom();
1.14 markus 843: /* If we got a packet, return it. */
1.56 millert 844: if (type != SSH_MSG_NONE) {
845: xfree(setp);
1.14 markus 846: return type;
1.56 millert 847: }
1.16 markus 848: /*
849: * Otherwise, wait for some data to arrive, add it to the
850: * buffer, and try again.
851: */
1.56 millert 852: memset(setp, 0, howmany(connection_in + 1, NFDBITS) *
853: sizeof(fd_mask));
854: FD_SET(connection_in, setp);
1.16 markus 855:
1.14 markus 856: /* Wait for some data to arrive. */
1.56 millert 857: while (select(connection_in + 1, setp, NULL, NULL, NULL) == -1 &&
1.51 deraadt 858: (errno == EAGAIN || errno == EINTR))
859: ;
1.16 markus 860:
1.14 markus 861: /* Read data from the socket. */
862: len = read(connection_in, buf, sizeof(buf));
1.18 markus 863: if (len == 0) {
1.106 itojun 864: logit("Connection closed by %.200s", get_remote_ipaddr());
1.112 markus 865: cleanup_exit(255);
1.18 markus 866: }
1.14 markus 867: if (len < 0)
868: fatal("Read from socket failed: %.100s", strerror(errno));
869: /* Append it to the buffer. */
870: packet_process_incoming(buf, len);
871: }
872: /* NOTREACHED */
1.1 deraadt 873: }
874:
1.77 djm 875: int
1.82 markus 876: packet_read(void)
1.77 djm 877: {
1.82 markus 878: return packet_read_seqnr(NULL);
1.77 djm 879: }
880:
1.16 markus 881: /*
882: * Waits until a packet has been received, verifies that its type matches
883: * that given, and gives a fatal error and exits if there is a mismatch.
884: */
1.1 deraadt 885:
1.2 provos 886: void
1.82 markus 887: packet_read_expect(int expected_type)
1.1 deraadt 888: {
1.14 markus 889: int type;
1.1 deraadt 890:
1.82 markus 891: type = packet_read();
1.14 markus 892: if (type != expected_type)
893: packet_disconnect("Protocol error: expected packet type %d, got %d",
1.25 markus 894: expected_type, type);
1.1 deraadt 895: }
896:
897: /* Checks if a full packet is available in the data received so far via
1.14 markus 898: * packet_process_incoming. If so, reads the packet; otherwise returns
899: * SSH_MSG_NONE. This does not wait for data from the connection.
900: *
901: * SSH_MSG_DISCONNECT is handled specially here. Also,
902: * SSH_MSG_IGNORE messages are skipped by this function and are never returned
903: * to higher levels.
904: */
1.1 deraadt 905:
1.68 itojun 906: static int
1.82 markus 907: packet_read_poll1(void)
1.1 deraadt 908: {
1.40 markus 909: u_int len, padded_len;
1.89 markus 910: u_char *cp, type;
1.40 markus 911: u_int checksum, stored_checksum;
1.14 markus 912:
913: /* Check if input size is less than minimum packet size. */
914: if (buffer_len(&input) < 4 + 8)
915: return SSH_MSG_NONE;
916: /* Get length of incoming packet. */
1.89 markus 917: cp = buffer_ptr(&input);
918: len = GET_32BIT(cp);
1.14 markus 919: if (len < 1 + 2 + 2 || len > 256 * 1024)
1.98 markus 920: packet_disconnect("Bad packet length %u.", len);
1.14 markus 921: padded_len = (len + 8) & ~7;
922:
923: /* Check if the packet has been entirely received. */
924: if (buffer_len(&input) < 4 + padded_len)
925: return SSH_MSG_NONE;
926:
927: /* The entire packet is in buffer. */
928:
929: /* Consume packet length. */
930: buffer_consume(&input, 4);
931:
1.62 markus 932: /*
933: * Cryptographic attack detector for ssh
934: * (C)1998 CORE-SDI, Buenos Aires Argentina
935: * Ariel Futoransky(futo@core-sdi.com)
936: */
1.88 markus 937: if (!receive_context.plaintext &&
1.62 markus 938: detect_attack(buffer_ptr(&input), padded_len, NULL) == DEATTACK_DETECTED)
939: packet_disconnect("crc32 compensation attack: network attack detected");
940:
941: /* Decrypt data to incoming_packet. */
1.14 markus 942: buffer_clear(&incoming_packet);
1.76 stevesk 943: cp = buffer_append_space(&incoming_packet, padded_len);
1.88 markus 944: cipher_crypt(&receive_context, cp, buffer_ptr(&input), padded_len);
1.62 markus 945:
1.14 markus 946: buffer_consume(&input, padded_len);
1.1 deraadt 947:
948: #ifdef PACKET_DEBUG
1.14 markus 949: fprintf(stderr, "read_poll plain: ");
950: buffer_dump(&incoming_packet);
1.1 deraadt 951: #endif
952:
1.14 markus 953: /* Compute packet checksum. */
1.83 stevesk 954: checksum = ssh_crc32(buffer_ptr(&incoming_packet),
1.25 markus 955: buffer_len(&incoming_packet) - 4);
1.14 markus 956:
957: /* Skip padding. */
958: buffer_consume(&incoming_packet, 8 - len % 8);
959:
960: /* Test check bytes. */
961: if (len != buffer_len(&incoming_packet))
1.77 djm 962: packet_disconnect("packet_read_poll1: len %d != buffer_len %d.",
1.25 markus 963: len, buffer_len(&incoming_packet));
1.14 markus 964:
1.89 markus 965: cp = (u_char *)buffer_ptr(&incoming_packet) + len - 4;
966: stored_checksum = GET_32BIT(cp);
1.14 markus 967: if (checksum != stored_checksum)
968: packet_disconnect("Corrupted check bytes on input.");
969: buffer_consume_end(&incoming_packet, 4);
970:
971: if (packet_compression) {
972: buffer_clear(&compression_buffer);
973: buffer_uncompress(&incoming_packet, &compression_buffer);
974: buffer_clear(&incoming_packet);
975: buffer_append(&incoming_packet, buffer_ptr(&compression_buffer),
1.25 markus 976: buffer_len(&compression_buffer));
1.14 markus 977: }
1.62 markus 978: type = buffer_get_char(&incoming_packet);
979: return type;
1.1 deraadt 980: }
1.14 markus 981:
1.68 itojun 982: static int
1.82 markus 983: packet_read_poll2(u_int32_t *seqnr_p)
1.25 markus 984: {
1.50 markus 985: static u_int packet_length = 0;
1.40 markus 986: u_int padlen, need;
1.89 markus 987: u_char *macbuf, *cp, type;
1.25 markus 988: int maclen, block_size;
989: Enc *enc = NULL;
990: Mac *mac = NULL;
991: Comp *comp = NULL;
992:
1.57 markus 993: if (newkeys[MODE_IN] != NULL) {
994: enc = &newkeys[MODE_IN]->enc;
995: mac = &newkeys[MODE_IN]->mac;
996: comp = &newkeys[MODE_IN]->comp;
1.25 markus 997: }
998: maclen = mac && mac->enabled ? mac->mac_len : 0;
1.88 markus 999: block_size = enc ? enc->block_size : 8;
1.25 markus 1000:
1001: if (packet_length == 0) {
1002: /*
1003: * check if input size is less than the cipher block size,
1004: * decrypt first block and extract length of incoming packet
1005: */
1006: if (buffer_len(&input) < block_size)
1007: return SSH_MSG_NONE;
1008: buffer_clear(&incoming_packet);
1.76 stevesk 1009: cp = buffer_append_space(&incoming_packet, block_size);
1.88 markus 1010: cipher_crypt(&receive_context, cp, buffer_ptr(&input),
1.25 markus 1011: block_size);
1.89 markus 1012: cp = buffer_ptr(&incoming_packet);
1013: packet_length = GET_32BIT(cp);
1.25 markus 1014: if (packet_length < 1 + 4 || packet_length > 256 * 1024) {
1.110 markus 1015: #ifdef PACKET_DEBUG
1.25 markus 1016: buffer_dump(&incoming_packet);
1.110 markus 1017: #endif
1.98 markus 1018: packet_disconnect("Bad packet length %u.", packet_length);
1.25 markus 1019: }
1.98 markus 1020: DBG(debug("input: packet len %u", packet_length+4));
1.25 markus 1021: buffer_consume(&input, block_size);
1022: }
1023: /* we have a partial packet of block_size bytes */
1024: need = 4 + packet_length - block_size;
1025: DBG(debug("partial packet %d, need %d, maclen %d", block_size,
1026: need, maclen));
1027: if (need % block_size != 0)
1028: fatal("padding error: need %d block %d mod %d",
1029: need, block_size, need % block_size);
1030: /*
1031: * check if the entire packet has been received and
1032: * decrypt into incoming_packet
1033: */
1034: if (buffer_len(&input) < need + maclen)
1035: return SSH_MSG_NONE;
1036: #ifdef PACKET_DEBUG
1037: fprintf(stderr, "read_poll enc/full: ");
1038: buffer_dump(&input);
1039: #endif
1.76 stevesk 1040: cp = buffer_append_space(&incoming_packet, need);
1.88 markus 1041: cipher_crypt(&receive_context, cp, buffer_ptr(&input), need);
1.25 markus 1042: buffer_consume(&input, need);
1043: /*
1044: * compute MAC over seqnr and packet,
1045: * increment sequence number for incoming packet
1046: */
1.29 markus 1047: if (mac && mac->enabled) {
1.105 markus 1048: macbuf = mac_compute(mac, p_read.seqnr,
1.83 stevesk 1049: buffer_ptr(&incoming_packet),
1.50 markus 1050: buffer_len(&incoming_packet));
1.25 markus 1051: if (memcmp(macbuf, buffer_ptr(&input), mac->mac_len) != 0)
1.36 markus 1052: packet_disconnect("Corrupted MAC on input.");
1.105 markus 1053: DBG(debug("MAC #%d ok", p_read.seqnr));
1.25 markus 1054: buffer_consume(&input, mac->mac_len);
1055: }
1.77 djm 1056: if (seqnr_p != NULL)
1.105 markus 1057: *seqnr_p = p_read.seqnr;
1058: if (++p_read.seqnr == 0)
1.106 itojun 1059: logit("incoming seqnr wraps around");
1.105 markus 1060: if (++p_read.packets == 0)
1061: if (!(datafellows & SSH_BUG_NOREKEY))
1062: fatal("XXX too many packets with same key");
1063: p_read.blocks += (packet_length + 4) / block_size;
1.25 markus 1064:
1065: /* get padlen */
1.76 stevesk 1066: cp = buffer_ptr(&incoming_packet);
1.89 markus 1067: padlen = cp[4];
1.25 markus 1068: DBG(debug("input: padlen %d", padlen));
1069: if (padlen < 4)
1070: packet_disconnect("Corrupted padlen %d on input.", padlen);
1071:
1072: /* skip packet size + padlen, discard padding */
1073: buffer_consume(&incoming_packet, 4 + 1);
1074: buffer_consume_end(&incoming_packet, padlen);
1075:
1076: DBG(debug("input: len before de-compress %d", buffer_len(&incoming_packet)));
1077: if (comp && comp->enabled) {
1078: buffer_clear(&compression_buffer);
1079: buffer_uncompress(&incoming_packet, &compression_buffer);
1080: buffer_clear(&incoming_packet);
1081: buffer_append(&incoming_packet, buffer_ptr(&compression_buffer),
1082: buffer_len(&compression_buffer));
1.97 deraadt 1083: DBG(debug("input: len after de-compress %d",
1084: buffer_len(&incoming_packet)));
1.25 markus 1085: }
1086: /*
1087: * get packet type, implies consume.
1088: * return length of payload (without type field)
1089: */
1.62 markus 1090: type = buffer_get_char(&incoming_packet);
1.57 markus 1091: if (type == SSH2_MSG_NEWKEYS)
1092: set_newkeys(MODE_IN);
1.25 markus 1093: #ifdef PACKET_DEBUG
1.55 deraadt 1094: fprintf(stderr, "read/plain[%d]:\r\n", type);
1.25 markus 1095: buffer_dump(&incoming_packet);
1096: #endif
1.62 markus 1097: /* reset for next packet */
1098: packet_length = 0;
1099: return type;
1.25 markus 1100: }
1101:
1102: int
1.82 markus 1103: packet_read_poll_seqnr(u_int32_t *seqnr_p)
1.25 markus 1104: {
1.96 deraadt 1105: u_int reason, seqnr;
1.62 markus 1106: u_char type;
1.25 markus 1107: char *msg;
1.62 markus 1108:
1.25 markus 1109: for (;;) {
1.62 markus 1110: if (compat20) {
1.82 markus 1111: type = packet_read_poll2(seqnr_p);
1.62 markus 1112: if (type)
1.25 markus 1113: DBG(debug("received packet type %d", type));
1.74 deraadt 1114: switch (type) {
1.25 markus 1115: case SSH2_MSG_IGNORE:
1116: break;
1117: case SSH2_MSG_DEBUG:
1118: packet_get_char();
1119: msg = packet_get_string(NULL);
1120: debug("Remote: %.900s", msg);
1121: xfree(msg);
1122: msg = packet_get_string(NULL);
1123: xfree(msg);
1124: break;
1125: case SSH2_MSG_DISCONNECT:
1126: reason = packet_get_int();
1127: msg = packet_get_string(NULL);
1.106 itojun 1128: logit("Received disconnect from %s: %u: %.400s",
1.96 deraadt 1129: get_remote_ipaddr(), reason, msg);
1.25 markus 1130: xfree(msg);
1.112 markus 1131: cleanup_exit(255);
1.84 markus 1132: break;
1133: case SSH2_MSG_UNIMPLEMENTED:
1134: seqnr = packet_get_int();
1.96 deraadt 1135: debug("Received SSH2_MSG_UNIMPLEMENTED for %u",
1136: seqnr);
1.25 markus 1137: break;
1138: default:
1139: return type;
1140: break;
1.48 stevesk 1141: }
1.25 markus 1142: } else {
1.82 markus 1143: type = packet_read_poll1();
1.74 deraadt 1144: switch (type) {
1.25 markus 1145: case SSH_MSG_IGNORE:
1146: break;
1147: case SSH_MSG_DEBUG:
1148: msg = packet_get_string(NULL);
1149: debug("Remote: %.900s", msg);
1150: xfree(msg);
1151: break;
1152: case SSH_MSG_DISCONNECT:
1153: msg = packet_get_string(NULL);
1.106 itojun 1154: logit("Received disconnect from %s: %.400s",
1.96 deraadt 1155: get_remote_ipaddr(), msg);
1.112 markus 1156: cleanup_exit(255);
1.25 markus 1157: xfree(msg);
1158: break;
1159: default:
1.62 markus 1160: if (type)
1.25 markus 1161: DBG(debug("received packet type %d", type));
1162: return type;
1163: break;
1.48 stevesk 1164: }
1.25 markus 1165: }
1166: }
1.77 djm 1167: }
1168:
1169: int
1.82 markus 1170: packet_read_poll(void)
1.77 djm 1171: {
1.82 markus 1172: return packet_read_poll_seqnr(NULL);
1.25 markus 1173: }
1174:
1.16 markus 1175: /*
1176: * Buffers the given amount of input characters. This is intended to be used
1177: * together with packet_read_poll.
1178: */
1.1 deraadt 1179:
1.2 provos 1180: void
1.40 markus 1181: packet_process_incoming(const char *buf, u_int len)
1.1 deraadt 1182: {
1.14 markus 1183: buffer_append(&input, buf, len);
1.1 deraadt 1184: }
1185:
1186: /* Returns a character from the packet. */
1187:
1.40 markus 1188: u_int
1.73 itojun 1189: packet_get_char(void)
1.1 deraadt 1190: {
1.14 markus 1191: char ch;
1.97 deraadt 1192:
1.14 markus 1193: buffer_get(&incoming_packet, &ch, 1);
1.40 markus 1194: return (u_char) ch;
1.1 deraadt 1195: }
1196:
1197: /* Returns an integer from the packet data. */
1198:
1.40 markus 1199: u_int
1.73 itojun 1200: packet_get_int(void)
1.1 deraadt 1201: {
1.14 markus 1202: return buffer_get_int(&incoming_packet);
1.1 deraadt 1203: }
1204:
1.16 markus 1205: /*
1206: * Returns an arbitrary precision integer from the packet data. The integer
1207: * must have been initialized before this call.
1208: */
1.1 deraadt 1209:
1.2 provos 1210: void
1.80 markus 1211: packet_get_bignum(BIGNUM * value)
1.1 deraadt 1212: {
1.81 markus 1213: buffer_get_bignum(&incoming_packet, value);
1.24 markus 1214: }
1215:
1216: void
1.80 markus 1217: packet_get_bignum2(BIGNUM * value)
1.24 markus 1218: {
1.81 markus 1219: buffer_get_bignum2(&incoming_packet, value);
1.24 markus 1220: }
1221:
1.76 stevesk 1222: void *
1.24 markus 1223: packet_get_raw(int *length_ptr)
1224: {
1225: int bytes = buffer_len(&incoming_packet);
1.97 deraadt 1226:
1.24 markus 1227: if (length_ptr != NULL)
1228: *length_ptr = bytes;
1229: return buffer_ptr(&incoming_packet);
1.28 markus 1230: }
1231:
1232: int
1233: packet_remaining(void)
1234: {
1235: return buffer_len(&incoming_packet);
1.1 deraadt 1236: }
1237:
1.16 markus 1238: /*
1239: * Returns a string from the packet data. The string is allocated using
1240: * xmalloc; it is the responsibility of the calling program to free it when
1241: * no longer needed. The length_ptr argument may be NULL, or point to an
1242: * integer into which the length of the string is stored.
1243: */
1.1 deraadt 1244:
1.76 stevesk 1245: void *
1.40 markus 1246: packet_get_string(u_int *length_ptr)
1.1 deraadt 1247: {
1.14 markus 1248: return buffer_get_string(&incoming_packet, length_ptr);
1.1 deraadt 1249: }
1250:
1.16 markus 1251: /*
1252: * Sends a diagnostic message from the server to the client. This message
1253: * can be sent at any time (but not while constructing another message). The
1254: * message is printed immediately, but only if the client is being executed
1255: * in verbose mode. These messages are primarily intended to ease debugging
1256: * authentication problems. The length of the formatted message must not
1257: * exceed 1024 bytes. This will automatically call packet_write_wait.
1258: */
1.1 deraadt 1259:
1.2 provos 1260: void
1.14 markus 1261: packet_send_debug(const char *fmt,...)
1.1 deraadt 1262: {
1.14 markus 1263: char buf[1024];
1264: va_list args;
1.39 markus 1265:
1266: if (compat20 && (datafellows & SSH_BUG_DEBUG))
1267: return;
1.14 markus 1268:
1269: va_start(args, fmt);
1270: vsnprintf(buf, sizeof(buf), fmt, args);
1271: va_end(args);
1272:
1.30 markus 1273: if (compat20) {
1274: packet_start(SSH2_MSG_DEBUG);
1275: packet_put_char(0); /* bool: always display */
1276: packet_put_cstring(buf);
1277: packet_put_cstring("");
1278: } else {
1279: packet_start(SSH_MSG_DEBUG);
1280: packet_put_cstring(buf);
1281: }
1.14 markus 1282: packet_send();
1283: packet_write_wait();
1.1 deraadt 1284: }
1285:
1.16 markus 1286: /*
1287: * Logs the error plus constructs and sends a disconnect packet, closes the
1288: * connection, and exits. This function never returns. The error message
1289: * should not contain a newline. The length of the formatted message must
1290: * not exceed 1024 bytes.
1291: */
1.1 deraadt 1292:
1.2 provos 1293: void
1.14 markus 1294: packet_disconnect(const char *fmt,...)
1.1 deraadt 1295: {
1.14 markus 1296: char buf[1024];
1297: va_list args;
1298: static int disconnecting = 0;
1.97 deraadt 1299:
1.14 markus 1300: if (disconnecting) /* Guard against recursive invocations. */
1301: fatal("packet_disconnect called recursively.");
1302: disconnecting = 1;
1303:
1.16 markus 1304: /*
1305: * Format the message. Note that the caller must make sure the
1306: * message is of limited size.
1307: */
1.14 markus 1308: va_start(args, fmt);
1309: vsnprintf(buf, sizeof(buf), fmt, args);
1310: va_end(args);
1311:
1.99 markus 1312: /* Display the error locally */
1.106 itojun 1313: logit("Disconnecting: %.100s", buf);
1.99 markus 1314:
1.14 markus 1315: /* Send the disconnect message to the other side, and wait for it to get sent. */
1.25 markus 1316: if (compat20) {
1317: packet_start(SSH2_MSG_DISCONNECT);
1318: packet_put_int(SSH2_DISCONNECT_PROTOCOL_ERROR);
1319: packet_put_cstring(buf);
1320: packet_put_cstring("");
1321: } else {
1322: packet_start(SSH_MSG_DISCONNECT);
1.65 markus 1323: packet_put_cstring(buf);
1.25 markus 1324: }
1.14 markus 1325: packet_send();
1326: packet_write_wait();
1327:
1328: /* Stop listening for connections. */
1.67 markus 1329: channel_close_all();
1.14 markus 1330:
1331: /* Close the connection. */
1332: packet_close();
1.112 markus 1333: cleanup_exit(255);
1.1 deraadt 1334: }
1335:
1.16 markus 1336: /* Checks if there is any buffered output, and tries to write some of the output. */
1.1 deraadt 1337:
1.2 provos 1338: void
1.73 itojun 1339: packet_write_poll(void)
1.1 deraadt 1340: {
1.14 markus 1341: int len = buffer_len(&output);
1.97 deraadt 1342:
1.14 markus 1343: if (len > 0) {
1344: len = write(connection_out, buffer_ptr(&output), len);
1345: if (len <= 0) {
1346: if (errno == EAGAIN)
1347: return;
1348: else
1349: fatal("Write failed: %.100s", strerror(errno));
1350: }
1351: buffer_consume(&output, len);
1352: }
1.1 deraadt 1353: }
1354:
1.16 markus 1355: /*
1356: * Calls packet_write_poll repeatedly until all pending output data has been
1357: * written.
1358: */
1.1 deraadt 1359:
1.2 provos 1360: void
1.73 itojun 1361: packet_write_wait(void)
1.1 deraadt 1362: {
1.56 millert 1363: fd_set *setp;
1364:
1365: setp = (fd_set *)xmalloc(howmany(connection_out + 1, NFDBITS) *
1366: sizeof(fd_mask));
1.14 markus 1367: packet_write_poll();
1368: while (packet_have_data_to_write()) {
1.56 millert 1369: memset(setp, 0, howmany(connection_out + 1, NFDBITS) *
1370: sizeof(fd_mask));
1371: FD_SET(connection_out, setp);
1372: while (select(connection_out + 1, NULL, setp, NULL, NULL) == -1 &&
1.51 deraadt 1373: (errno == EAGAIN || errno == EINTR))
1374: ;
1.14 markus 1375: packet_write_poll();
1376: }
1.56 millert 1377: xfree(setp);
1.1 deraadt 1378: }
1379:
1380: /* Returns true if there is buffered data to write to the connection. */
1381:
1.2 provos 1382: int
1.73 itojun 1383: packet_have_data_to_write(void)
1.1 deraadt 1384: {
1.14 markus 1385: return buffer_len(&output) != 0;
1.1 deraadt 1386: }
1387:
1388: /* Returns true if there is not too much data to write to the connection. */
1389:
1.2 provos 1390: int
1.73 itojun 1391: packet_not_very_much_data_to_write(void)
1.1 deraadt 1392: {
1.14 markus 1393: if (interactive_mode)
1394: return buffer_len(&output) < 16384;
1395: else
1396: return buffer_len(&output) < 128 * 1024;
1.1 deraadt 1397: }
1398:
1.102 markus 1399: static void
1.101 markus 1400: packet_set_tos(int interactive)
1401: {
1402: int tos = interactive ? IPTOS_LOWDELAY : IPTOS_THROUGHPUT;
1403:
1404: if (!packet_connection_is_on_socket() ||
1405: !packet_connection_is_ipv4())
1406: return;
1407: if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, &tos,
1408: sizeof(tos)) < 0)
1409: error("setsockopt IP_TOS %d: %.100s:",
1410: tos, strerror(errno));
1411: }
1412:
1.1 deraadt 1413: /* Informs that the current session is interactive. Sets IP flags for that. */
1414:
1.2 provos 1415: void
1.43 markus 1416: packet_set_interactive(int interactive)
1.1 deraadt 1417: {
1.43 markus 1418: static int called = 0;
1.44 markus 1419:
1.43 markus 1420: if (called)
1421: return;
1422: called = 1;
1.1 deraadt 1423:
1.14 markus 1424: /* Record that we are in interactive mode. */
1425: interactive_mode = interactive;
1.1 deraadt 1426:
1.19 markus 1427: /* Only set socket options if using a socket. */
1428: if (!packet_connection_is_on_socket())
1.14 markus 1429: return;
1.101 markus 1430: if (interactive)
1.86 stevesk 1431: set_nodelay(connection_in);
1.101 markus 1432: packet_set_tos(interactive);
1.1 deraadt 1433: }
1434:
1435: /* Returns true if the current connection is interactive. */
1436:
1.2 provos 1437: int
1.73 itojun 1438: packet_is_interactive(void)
1.1 deraadt 1439: {
1.14 markus 1440: return interactive_mode;
1.12 markus 1441: }
1442:
1.113 deraadt 1443: int
1.108 markus 1444: packet_set_maxsize(u_int s)
1.12 markus 1445: {
1.14 markus 1446: static int called = 0;
1.97 deraadt 1447:
1.14 markus 1448: if (called) {
1.106 itojun 1449: logit("packet_set_maxsize: called twice: old %d new %d",
1.25 markus 1450: max_packet_size, s);
1.14 markus 1451: return -1;
1452: }
1453: if (s < 4 * 1024 || s > 1024 * 1024) {
1.106 itojun 1454: logit("packet_set_maxsize: bad size %d", s);
1.14 markus 1455: return -1;
1456: }
1.70 markus 1457: called = 1;
1.66 markus 1458: debug("packet_set_maxsize: setting to %d", s);
1.14 markus 1459: max_packet_size = s;
1460: return s;
1.53 markus 1461: }
1462:
1.71 markus 1463: /* roundup current message to pad bytes */
1464: void
1465: packet_add_padding(u_char pad)
1466: {
1467: extra_pad = pad;
1468: }
1469:
1.53 markus 1470: /*
1471: * 9.2. Ignored Data Message
1.61 markus 1472: *
1.53 markus 1473: * byte SSH_MSG_IGNORE
1474: * string data
1.61 markus 1475: *
1.53 markus 1476: * All implementations MUST understand (and ignore) this message at any
1477: * time (after receiving the protocol version). No implementation is
1478: * required to send them. This message can be used as an additional
1479: * protection measure against advanced traffic analysis techniques.
1480: */
1.54 markus 1481: void
1482: packet_send_ignore(int nbytes)
1483: {
1484: u_int32_t rand = 0;
1485: int i;
1486:
1487: packet_start(compat20 ? SSH2_MSG_IGNORE : SSH_MSG_IGNORE);
1.53 markus 1488: packet_put_int(nbytes);
1.75 deraadt 1489: for (i = 0; i < nbytes; i++) {
1.53 markus 1490: if (i % 4 == 0)
1491: rand = arc4random();
1492: packet_put_char(rand & 0xff);
1493: rand >>= 8;
1494: }
1.105 markus 1495: }
1496:
1.113 deraadt 1497: #define MAX_PACKETS (1U<<31)
1.105 markus 1498: int
1499: packet_need_rekeying(void)
1500: {
1501: if (datafellows & SSH_BUG_NOREKEY)
1502: return 0;
1503: return
1504: (p_send.packets > MAX_PACKETS) ||
1505: (p_read.packets > MAX_PACKETS) ||
1506: (max_blocks_out && (p_send.blocks > max_blocks_out)) ||
1507: (max_blocks_in && (p_read.blocks > max_blocks_in));
1508: }
1509:
1510: void
1511: packet_set_rekey_limit(u_int32_t bytes)
1512: {
1513: rekey_limit = bytes;
1.1 deraadt 1514: }
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