Annotation of src/usr.bin/ssh/packet.c, Revision 1.121.2.1
1.121.2.1! brad 1: /* $OpenBSD: packet.c,v 1.144 2006/09/16 19:53:37 djm Exp $ */
1.1 deraadt 2: /*
1.15 deraadt 3: * Author: Tatu Ylonen <ylo@cs.hut.fi>
4: * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5: * All rights reserved
1.35 deraadt 6: * This file contains code implementing the packet protocol and communication
7: * with the other side. This same code is used both on client and server side.
1.29 markus 8: *
1.35 deraadt 9: * As far as I am concerned, the code I have written for this software
10: * can be used freely for any purpose. Any derived versions of this
11: * software must be clearly marked as such, and if the derived work is
12: * incompatible with the protocol description in the RFC file, it must be
13: * called by a name other than "ssh" or "Secure Shell".
1.29 markus 14: *
1.25 markus 15: *
16: * SSH2 packet format added by Markus Friedl.
1.69 markus 17: * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
1.25 markus 18: *
1.35 deraadt 19: * Redistribution and use in source and binary forms, with or without
20: * modification, are permitted provided that the following conditions
21: * are met:
22: * 1. Redistributions of source code must retain the above copyright
23: * notice, this list of conditions and the following disclaimer.
24: * 2. Redistributions in binary form must reproduce the above copyright
25: * notice, this list of conditions and the following disclaimer in the
26: * documentation and/or other materials provided with the distribution.
27: *
28: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
29: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
30: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
31: * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
32: * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
33: * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
34: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
35: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
36: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
37: * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1.15 deraadt 38: */
1.1 deraadt 39:
1.121.2.1! brad 40: #include <sys/types.h>
1.105 markus 41: #include <sys/queue.h>
1.121.2.1! brad 42: #include <sys/socket.h>
! 43: #include <sys/time.h>
! 44: #include <sys/param.h>
1.121 stevesk 45:
46: #include <netinet/in_systm.h>
1.121.2.1! brad 47: #include <netinet/in.h>
1.121 stevesk 48: #include <netinet/ip.h>
1.1 deraadt 49:
1.121.2.1! brad 50: #include <errno.h>
! 51: #include <stdarg.h>
! 52: #include <stdio.h>
! 53: #include <stdlib.h>
! 54: #include <string.h>
! 55: #include <unistd.h>
! 56: #include <signal.h>
! 57:
1.1 deraadt 58: #include "xmalloc.h"
59: #include "buffer.h"
60: #include "packet.h"
61: #include "crc32.h"
62: #include "compress.h"
1.9 dugsong 63: #include "deattack.h"
1.64 markus 64: #include "channels.h"
1.25 markus 65: #include "compat.h"
1.45 markus 66: #include "ssh1.h"
1.25 markus 67: #include "ssh2.h"
1.37 markus 68: #include "cipher.h"
1.121.2.1! brad 69: #include "key.h"
1.25 markus 70: #include "kex.h"
1.50 markus 71: #include "mac.h"
1.46 markus 72: #include "log.h"
73: #include "canohost.h"
1.87 stevesk 74: #include "misc.h"
1.95 markus 75: #include "ssh.h"
1.25 markus 76:
77: #ifdef PACKET_DEBUG
78: #define DBG(x) x
79: #else
80: #define DBG(x)
81: #endif
82:
1.16 markus 83: /*
84: * This variable contains the file descriptors used for communicating with
85: * the other side. connection_in is used for reading; connection_out for
86: * writing. These can be the same descriptor, in which case it is assumed to
87: * be a socket.
88: */
1.1 deraadt 89: static int connection_in = -1;
90: static int connection_out = -1;
91:
92: /* Protocol flags for the remote side. */
1.40 markus 93: static u_int remote_protocol_flags = 0;
1.1 deraadt 94:
95: /* Encryption context for receiving data. This is only used for decryption. */
96: static CipherContext receive_context;
1.14 markus 97:
98: /* Encryption context for sending data. This is only used for encryption. */
1.1 deraadt 99: static CipherContext send_context;
100:
101: /* Buffer for raw input data from the socket. */
1.91 markus 102: Buffer input;
1.1 deraadt 103:
104: /* Buffer for raw output data going to the socket. */
1.91 markus 105: Buffer output;
1.1 deraadt 106:
107: /* Buffer for the partial outgoing packet being constructed. */
108: static Buffer outgoing_packet;
109:
110: /* Buffer for the incoming packet currently being processed. */
111: static Buffer incoming_packet;
112:
113: /* Scratch buffer for packet compression/decompression. */
114: static Buffer compression_buffer;
1.60 markus 115: static int compression_buffer_ready = 0;
1.1 deraadt 116:
117: /* Flag indicating whether packet compression/decompression is enabled. */
118: static int packet_compression = 0;
119:
1.12 markus 120: /* default maximum packet size */
1.108 markus 121: u_int max_packet_size = 32768;
1.12 markus 122:
1.1 deraadt 123: /* Flag indicating whether this module has been initialized. */
124: static int initialized = 0;
125:
126: /* Set to true if the connection is interactive. */
127: static int interactive_mode = 0;
128:
1.118 markus 129: /* Set to true if we are the server side. */
130: static int server_side = 0;
131:
132: /* Set to true if we are authenticated. */
133: static int after_authentication = 0;
134:
1.25 markus 135: /* Session key information for Encryption and MAC */
1.57 markus 136: Newkeys *newkeys[MODE_MAX];
1.105 markus 137: static struct packet_state {
138: u_int32_t seqnr;
139: u_int32_t packets;
140: u_int64_t blocks;
141: } p_read, p_send;
142:
143: static u_int64_t max_blocks_in, max_blocks_out;
144: static u_int32_t rekey_limit;
1.25 markus 145:
1.95 markus 146: /* Session key for protocol v1 */
147: static u_char ssh1_key[SSH_SESSION_KEY_LENGTH];
148: static u_int ssh1_keylen;
149:
1.71 markus 150: /* roundup current message to extra_pad bytes */
151: static u_char extra_pad = 0;
152:
1.105 markus 153: struct packet {
154: TAILQ_ENTRY(packet) next;
155: u_char type;
156: Buffer payload;
157: };
158: TAILQ_HEAD(, packet) outgoing;
159:
1.16 markus 160: /*
161: * Sets the descriptors used for communication. Disables encryption until
162: * packet_set_encryption_key is called.
163: */
1.2 provos 164: void
165: packet_set_connection(int fd_in, int fd_out)
1.1 deraadt 166: {
1.37 markus 167: Cipher *none = cipher_by_name("none");
1.97 deraadt 168:
1.37 markus 169: if (none == NULL)
170: fatal("packet_set_connection: cannot load cipher 'none'");
1.14 markus 171: connection_in = fd_in;
172: connection_out = fd_out;
1.113 deraadt 173: cipher_init(&send_context, none, (const u_char *)"",
174: 0, NULL, 0, CIPHER_ENCRYPT);
175: cipher_init(&receive_context, none, (const u_char *)"",
176: 0, NULL, 0, CIPHER_DECRYPT);
1.62 markus 177: newkeys[MODE_IN] = newkeys[MODE_OUT] = NULL;
1.14 markus 178: if (!initialized) {
179: initialized = 1;
180: buffer_init(&input);
181: buffer_init(&output);
182: buffer_init(&outgoing_packet);
183: buffer_init(&incoming_packet);
1.105 markus 184: TAILQ_INIT(&outgoing);
1.14 markus 185: }
1.1 deraadt 186: }
187:
1.19 markus 188: /* Returns 1 if remote host is connected via socket, 0 if not. */
189:
190: int
1.73 itojun 191: packet_connection_is_on_socket(void)
1.19 markus 192: {
193: struct sockaddr_storage from, to;
194: socklen_t fromlen, tolen;
195:
196: /* filedescriptors in and out are the same, so it's a socket */
197: if (connection_in == connection_out)
198: return 1;
199: fromlen = sizeof(from);
200: memset(&from, 0, sizeof(from));
1.20 markus 201: if (getpeername(connection_in, (struct sockaddr *)&from, &fromlen) < 0)
1.19 markus 202: return 0;
203: tolen = sizeof(to);
204: memset(&to, 0, sizeof(to));
1.20 markus 205: if (getpeername(connection_out, (struct sockaddr *)&to, &tolen) < 0)
1.19 markus 206: return 0;
207: if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0)
208: return 0;
209: if (from.ss_family != AF_INET && from.ss_family != AF_INET6)
210: return 0;
211: return 1;
212: }
213:
1.92 markus 214: /*
1.91 markus 215: * Exports an IV from the CipherContext required to export the key
216: * state back from the unprivileged child to the privileged parent
217: * process.
218: */
219:
220: void
221: packet_get_keyiv(int mode, u_char *iv, u_int len)
222: {
223: CipherContext *cc;
224:
225: if (mode == MODE_OUT)
226: cc = &send_context;
227: else
228: cc = &receive_context;
229:
230: cipher_get_keyiv(cc, iv, len);
231: }
232:
233: int
234: packet_get_keycontext(int mode, u_char *dat)
235: {
236: CipherContext *cc;
1.92 markus 237:
1.91 markus 238: if (mode == MODE_OUT)
239: cc = &send_context;
240: else
241: cc = &receive_context;
242:
243: return (cipher_get_keycontext(cc, dat));
244: }
245:
246: void
247: packet_set_keycontext(int mode, u_char *dat)
248: {
249: CipherContext *cc;
1.92 markus 250:
1.91 markus 251: if (mode == MODE_OUT)
252: cc = &send_context;
253: else
254: cc = &receive_context;
255:
256: cipher_set_keycontext(cc, dat);
257: }
258:
259: int
260: packet_get_keyiv_len(int mode)
261: {
262: CipherContext *cc;
263:
264: if (mode == MODE_OUT)
265: cc = &send_context;
266: else
267: cc = &receive_context;
268:
269: return (cipher_get_keyiv_len(cc));
270: }
1.121.2.1! brad 271:
1.91 markus 272: void
273: packet_set_iv(int mode, u_char *dat)
274: {
275: CipherContext *cc;
276:
277: if (mode == MODE_OUT)
278: cc = &send_context;
279: else
280: cc = &receive_context;
281:
282: cipher_set_keyiv(cc, dat);
283: }
1.121.2.1! brad 284:
1.91 markus 285: int
1.107 deraadt 286: packet_get_ssh1_cipher(void)
1.91 markus 287: {
288: return (cipher_get_number(receive_context.cipher));
289: }
290:
1.105 markus 291: void
292: packet_get_state(int mode, u_int32_t *seqnr, u_int64_t *blocks, u_int32_t *packets)
293: {
294: struct packet_state *state;
1.104 markus 295:
1.105 markus 296: state = (mode == MODE_IN) ? &p_read : &p_send;
297: *seqnr = state->seqnr;
298: *blocks = state->blocks;
299: *packets = state->packets;
1.91 markus 300: }
301:
302: void
1.105 markus 303: packet_set_state(int mode, u_int32_t seqnr, u_int64_t blocks, u_int32_t packets)
1.91 markus 304: {
1.105 markus 305: struct packet_state *state;
306:
307: state = (mode == MODE_IN) ? &p_read : &p_send;
308: state->seqnr = seqnr;
309: state->blocks = blocks;
310: state->packets = packets;
1.91 markus 311: }
312:
1.19 markus 313: /* returns 1 if connection is via ipv4 */
314:
315: int
1.73 itojun 316: packet_connection_is_ipv4(void)
1.19 markus 317: {
318: struct sockaddr_storage to;
1.21 deraadt 319: socklen_t tolen = sizeof(to);
1.19 markus 320:
321: memset(&to, 0, sizeof(to));
322: if (getsockname(connection_out, (struct sockaddr *)&to, &tolen) < 0)
323: return 0;
324: if (to.ss_family != AF_INET)
325: return 0;
326: return 1;
327: }
328:
1.1 deraadt 329: /* Sets the connection into non-blocking mode. */
330:
1.2 provos 331: void
1.73 itojun 332: packet_set_nonblocking(void)
1.1 deraadt 333: {
1.14 markus 334: /* Set the socket into non-blocking mode. */
1.114 djm 335: set_nonblock(connection_in);
1.14 markus 336:
1.114 djm 337: if (connection_out != connection_in)
338: set_nonblock(connection_out);
1.1 deraadt 339: }
340:
341: /* Returns the socket used for reading. */
342:
1.2 provos 343: int
1.73 itojun 344: packet_get_connection_in(void)
1.1 deraadt 345: {
1.14 markus 346: return connection_in;
1.1 deraadt 347: }
348:
349: /* Returns the descriptor used for writing. */
350:
1.2 provos 351: int
1.73 itojun 352: packet_get_connection_out(void)
1.1 deraadt 353: {
1.14 markus 354: return connection_out;
1.1 deraadt 355: }
356:
357: /* Closes the connection and clears and frees internal data structures. */
358:
1.2 provos 359: void
1.73 itojun 360: packet_close(void)
1.1 deraadt 361: {
1.14 markus 362: if (!initialized)
363: return;
364: initialized = 0;
365: if (connection_in == connection_out) {
366: shutdown(connection_out, SHUT_RDWR);
367: close(connection_out);
368: } else {
369: close(connection_in);
370: close(connection_out);
371: }
372: buffer_free(&input);
373: buffer_free(&output);
374: buffer_free(&outgoing_packet);
375: buffer_free(&incoming_packet);
1.60 markus 376: if (compression_buffer_ready) {
1.14 markus 377: buffer_free(&compression_buffer);
378: buffer_compress_uninit();
379: }
1.88 markus 380: cipher_cleanup(&send_context);
381: cipher_cleanup(&receive_context);
1.1 deraadt 382: }
383:
384: /* Sets remote side protocol flags. */
385:
1.2 provos 386: void
1.40 markus 387: packet_set_protocol_flags(u_int protocol_flags)
1.1 deraadt 388: {
1.14 markus 389: remote_protocol_flags = protocol_flags;
1.1 deraadt 390: }
391:
392: /* Returns the remote protocol flags set earlier by the above function. */
393:
1.40 markus 394: u_int
1.73 itojun 395: packet_get_protocol_flags(void)
1.1 deraadt 396: {
1.14 markus 397: return remote_protocol_flags;
1.1 deraadt 398: }
399:
1.16 markus 400: /*
401: * Starts packet compression from the next packet on in both directions.
402: * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip.
403: */
1.1 deraadt 404:
1.68 itojun 405: static void
406: packet_init_compression(void)
1.60 markus 407: {
408: if (compression_buffer_ready == 1)
409: return;
410: compression_buffer_ready = 1;
411: buffer_init(&compression_buffer);
412: }
413:
1.2 provos 414: void
415: packet_start_compression(int level)
1.1 deraadt 416: {
1.62 markus 417: if (packet_compression && !compat20)
1.14 markus 418: fatal("Compression already enabled.");
419: packet_compression = 1;
1.60 markus 420: packet_init_compression();
421: buffer_compress_init_send(level);
422: buffer_compress_init_recv();
1.1 deraadt 423: }
424:
1.16 markus 425: /*
426: * Causes any further packets to be encrypted using the given key. The same
427: * key is used for both sending and reception. However, both directions are
428: * encrypted independently of each other.
429: */
1.95 markus 430:
1.2 provos 431: void
1.40 markus 432: packet_set_encryption_key(const u_char *key, u_int keylen,
1.37 markus 433: int number)
1.1 deraadt 434: {
1.37 markus 435: Cipher *cipher = cipher_by_number(number);
1.97 deraadt 436:
1.37 markus 437: if (cipher == NULL)
438: fatal("packet_set_encryption_key: unknown cipher number %d", number);
1.25 markus 439: if (keylen < 20)
1.37 markus 440: fatal("packet_set_encryption_key: keylen too small: %d", keylen);
1.95 markus 441: if (keylen > SSH_SESSION_KEY_LENGTH)
442: fatal("packet_set_encryption_key: keylen too big: %d", keylen);
443: memcpy(ssh1_key, key, keylen);
444: ssh1_keylen = keylen;
1.88 markus 445: cipher_init(&send_context, cipher, key, keylen, NULL, 0, CIPHER_ENCRYPT);
446: cipher_init(&receive_context, cipher, key, keylen, NULL, 0, CIPHER_DECRYPT);
1.95 markus 447: }
448:
449: u_int
450: packet_get_encryption_key(u_char *key)
451: {
452: if (key == NULL)
453: return (ssh1_keylen);
454: memcpy(key, ssh1_key, ssh1_keylen);
455: return (ssh1_keylen);
1.1 deraadt 456: }
457:
1.62 markus 458: /* Start constructing a packet to send. */
1.2 provos 459: void
1.62 markus 460: packet_start(u_char type)
1.1 deraadt 461: {
1.62 markus 462: u_char buf[9];
463: int len;
1.1 deraadt 464:
1.62 markus 465: DBG(debug("packet_start[%d]", type));
466: len = compat20 ? 6 : 9;
467: memset(buf, 0, len - 1);
468: buf[len - 1] = type;
1.14 markus 469: buffer_clear(&outgoing_packet);
1.62 markus 470: buffer_append(&outgoing_packet, buf, len);
1.25 markus 471: }
472:
1.62 markus 473: /* Append payload. */
1.2 provos 474: void
475: packet_put_char(int value)
1.1 deraadt 476: {
1.14 markus 477: char ch = value;
1.97 deraadt 478:
1.14 markus 479: buffer_append(&outgoing_packet, &ch, 1);
1.1 deraadt 480: }
1.121.2.1! brad 481:
1.2 provos 482: void
1.40 markus 483: packet_put_int(u_int value)
1.1 deraadt 484: {
1.14 markus 485: buffer_put_int(&outgoing_packet, value);
1.1 deraadt 486: }
1.121.2.1! brad 487:
1.2 provos 488: void
1.76 stevesk 489: packet_put_string(const void *buf, u_int len)
1.1 deraadt 490: {
1.14 markus 491: buffer_put_string(&outgoing_packet, buf, len);
1.1 deraadt 492: }
1.121.2.1! brad 493:
1.24 markus 494: void
495: packet_put_cstring(const char *str)
496: {
1.65 markus 497: buffer_put_cstring(&outgoing_packet, str);
1.24 markus 498: }
1.121.2.1! brad 499:
1.24 markus 500: void
1.76 stevesk 501: packet_put_raw(const void *buf, u_int len)
1.24 markus 502: {
503: buffer_append(&outgoing_packet, buf, len);
504: }
1.121.2.1! brad 505:
1.2 provos 506: void
1.14 markus 507: packet_put_bignum(BIGNUM * value)
1.1 deraadt 508: {
1.14 markus 509: buffer_put_bignum(&outgoing_packet, value);
1.1 deraadt 510: }
1.121.2.1! brad 511:
1.24 markus 512: void
513: packet_put_bignum2(BIGNUM * value)
514: {
515: buffer_put_bignum2(&outgoing_packet, value);
516: }
1.1 deraadt 517:
1.16 markus 518: /*
519: * Finalizes and sends the packet. If the encryption key has been set,
520: * encrypts the packet before sending.
521: */
1.14 markus 522:
1.68 itojun 523: static void
1.49 itojun 524: packet_send1(void)
1.1 deraadt 525: {
1.89 markus 526: u_char buf[8], *cp;
1.14 markus 527: int i, padding, len;
1.40 markus 528: u_int checksum;
1.115 avsm 529: u_int32_t rnd = 0;
1.14 markus 530:
1.16 markus 531: /*
532: * If using packet compression, compress the payload of the outgoing
533: * packet.
534: */
1.14 markus 535: if (packet_compression) {
536: buffer_clear(&compression_buffer);
537: /* Skip padding. */
538: buffer_consume(&outgoing_packet, 8);
539: /* padding */
540: buffer_append(&compression_buffer, "\0\0\0\0\0\0\0\0", 8);
541: buffer_compress(&outgoing_packet, &compression_buffer);
542: buffer_clear(&outgoing_packet);
543: buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer),
1.75 deraadt 544: buffer_len(&compression_buffer));
1.14 markus 545: }
546: /* Compute packet length without padding (add checksum, remove padding). */
547: len = buffer_len(&outgoing_packet) + 4 - 8;
548:
1.32 markus 549: /* Insert padding. Initialized to zero in packet_start1() */
1.14 markus 550: padding = 8 - len % 8;
1.88 markus 551: if (!send_context.plaintext) {
1.14 markus 552: cp = buffer_ptr(&outgoing_packet);
553: for (i = 0; i < padding; i++) {
554: if (i % 4 == 0)
1.115 avsm 555: rnd = arc4random();
556: cp[7 - i] = rnd & 0xff;
557: rnd >>= 8;
1.14 markus 558: }
559: }
560: buffer_consume(&outgoing_packet, 8 - padding);
561:
562: /* Add check bytes. */
1.83 stevesk 563: checksum = ssh_crc32(buffer_ptr(&outgoing_packet),
1.34 deraadt 564: buffer_len(&outgoing_packet));
1.121.2.1! brad 565: put_u32(buf, checksum);
1.14 markus 566: buffer_append(&outgoing_packet, buf, 4);
1.1 deraadt 567:
568: #ifdef PACKET_DEBUG
1.14 markus 569: fprintf(stderr, "packet_send plain: ");
570: buffer_dump(&outgoing_packet);
1.1 deraadt 571: #endif
572:
1.14 markus 573: /* Append to output. */
1.121.2.1! brad 574: put_u32(buf, len);
1.14 markus 575: buffer_append(&output, buf, 4);
1.76 stevesk 576: cp = buffer_append_space(&output, buffer_len(&outgoing_packet));
1.88 markus 577: cipher_crypt(&send_context, cp, buffer_ptr(&outgoing_packet),
1.75 deraadt 578: buffer_len(&outgoing_packet));
1.14 markus 579:
1.1 deraadt 580: #ifdef PACKET_DEBUG
1.14 markus 581: fprintf(stderr, "encrypted: ");
582: buffer_dump(&output);
1.1 deraadt 583: #endif
584:
1.14 markus 585: buffer_clear(&outgoing_packet);
1.1 deraadt 586:
1.16 markus 587: /*
1.120 djm 588: * Note that the packet is now only buffered in output. It won't be
1.16 markus 589: * actually sent until packet_write_wait or packet_write_poll is
590: * called.
591: */
1.1 deraadt 592: }
593:
1.91 markus 594: void
1.57 markus 595: set_newkeys(int mode)
596: {
597: Enc *enc;
598: Mac *mac;
599: Comp *comp;
600: CipherContext *cc;
1.105 markus 601: u_int64_t *max_blocks;
1.115 avsm 602: int crypt_type;
1.57 markus 603:
1.100 markus 604: debug2("set_newkeys: mode %d", mode);
1.57 markus 605:
1.88 markus 606: if (mode == MODE_OUT) {
607: cc = &send_context;
1.115 avsm 608: crypt_type = CIPHER_ENCRYPT;
1.105 markus 609: p_send.packets = p_send.blocks = 0;
610: max_blocks = &max_blocks_out;
1.88 markus 611: } else {
612: cc = &receive_context;
1.115 avsm 613: crypt_type = CIPHER_DECRYPT;
1.105 markus 614: p_read.packets = p_read.blocks = 0;
615: max_blocks = &max_blocks_in;
1.88 markus 616: }
1.57 markus 617: if (newkeys[mode] != NULL) {
1.100 markus 618: debug("set_newkeys: rekeying");
1.88 markus 619: cipher_cleanup(cc);
1.59 markus 620: enc = &newkeys[mode]->enc;
621: mac = &newkeys[mode]->mac;
622: comp = &newkeys[mode]->comp;
1.61 markus 623: memset(mac->key, 0, mac->key_len);
1.59 markus 624: xfree(enc->name);
625: xfree(enc->iv);
626: xfree(enc->key);
627: xfree(mac->name);
628: xfree(mac->key);
629: xfree(comp->name);
1.58 markus 630: xfree(newkeys[mode]);
1.57 markus 631: }
632: newkeys[mode] = kex_get_newkeys(mode);
633: if (newkeys[mode] == NULL)
634: fatal("newkeys: no keys for mode %d", mode);
635: enc = &newkeys[mode]->enc;
636: mac = &newkeys[mode]->mac;
637: comp = &newkeys[mode]->comp;
638: if (mac->md != NULL)
639: mac->enabled = 1;
640: DBG(debug("cipher_init_context: %d", mode));
1.88 markus 641: cipher_init(cc, enc->cipher, enc->key, enc->key_len,
1.115 avsm 642: enc->iv, enc->block_size, crypt_type);
1.91 markus 643: /* Deleting the keys does not gain extra security */
644: /* memset(enc->iv, 0, enc->block_size);
645: memset(enc->key, 0, enc->key_len); */
1.118 markus 646: if ((comp->type == COMP_ZLIB ||
647: (comp->type == COMP_DELAYED && after_authentication)) &&
648: comp->enabled == 0) {
1.60 markus 649: packet_init_compression();
650: if (mode == MODE_OUT)
651: buffer_compress_init_send(6);
652: else
653: buffer_compress_init_recv();
1.57 markus 654: comp->enabled = 1;
655: }
1.109 markus 656: /*
657: * The 2^(blocksize*2) limit is too expensive for 3DES,
658: * blowfish, etc, so enforce a 1GB limit for small blocksizes.
659: */
660: if (enc->block_size >= 16)
661: *max_blocks = (u_int64_t)1 << (enc->block_size*2);
662: else
663: *max_blocks = ((u_int64_t)1 << 30) / enc->block_size;
1.105 markus 664: if (rekey_limit)
665: *max_blocks = MIN(*max_blocks, rekey_limit / enc->block_size);
1.57 markus 666: }
667:
1.16 markus 668: /*
1.118 markus 669: * Delayed compression for SSH2 is enabled after authentication:
1.121.2.1! brad 670: * This happens on the server side after a SSH2_MSG_USERAUTH_SUCCESS is sent,
1.118 markus 671: * and on the client side after a SSH2_MSG_USERAUTH_SUCCESS is received.
672: */
673: static void
674: packet_enable_delayed_compress(void)
675: {
676: Comp *comp = NULL;
677: int mode;
678:
679: /*
680: * Remember that we are past the authentication step, so rekeying
681: * with COMP_DELAYED will turn on compression immediately.
682: */
683: after_authentication = 1;
684: for (mode = 0; mode < MODE_MAX; mode++) {
685: comp = &newkeys[mode]->comp;
686: if (comp && !comp->enabled && comp->type == COMP_DELAYED) {
1.119 markus 687: packet_init_compression();
1.118 markus 688: if (mode == MODE_OUT)
689: buffer_compress_init_send(6);
690: else
691: buffer_compress_init_recv();
692: comp->enabled = 1;
693: }
694: }
695: }
696:
697: /*
1.25 markus 698: * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue)
699: */
1.68 itojun 700: static void
1.105 markus 701: packet_send2_wrapped(void)
1.25 markus 702: {
1.89 markus 703: u_char type, *cp, *macbuf = NULL;
1.71 markus 704: u_char padlen, pad;
1.40 markus 705: u_int packet_length = 0;
1.71 markus 706: u_int i, len;
1.115 avsm 707: u_int32_t rnd = 0;
1.25 markus 708: Enc *enc = NULL;
709: Mac *mac = NULL;
710: Comp *comp = NULL;
711: int block_size;
712:
1.57 markus 713: if (newkeys[MODE_OUT] != NULL) {
714: enc = &newkeys[MODE_OUT]->enc;
715: mac = &newkeys[MODE_OUT]->mac;
716: comp = &newkeys[MODE_OUT]->comp;
1.25 markus 717: }
1.88 markus 718: block_size = enc ? enc->block_size : 8;
1.25 markus 719:
1.89 markus 720: cp = buffer_ptr(&outgoing_packet);
721: type = cp[5];
1.25 markus 722:
723: #ifdef PACKET_DEBUG
724: fprintf(stderr, "plain: ");
725: buffer_dump(&outgoing_packet);
726: #endif
727:
728: if (comp && comp->enabled) {
729: len = buffer_len(&outgoing_packet);
730: /* skip header, compress only payload */
731: buffer_consume(&outgoing_packet, 5);
732: buffer_clear(&compression_buffer);
733: buffer_compress(&outgoing_packet, &compression_buffer);
734: buffer_clear(&outgoing_packet);
735: buffer_append(&outgoing_packet, "\0\0\0\0\0", 5);
736: buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer),
737: buffer_len(&compression_buffer));
738: DBG(debug("compression: raw %d compressed %d", len,
739: buffer_len(&outgoing_packet)));
740: }
741:
742: /* sizeof (packet_len + pad_len + payload) */
743: len = buffer_len(&outgoing_packet);
744:
745: /*
746: * calc size of padding, alloc space, get random data,
747: * minimum padding is 4 bytes
748: */
749: padlen = block_size - (len % block_size);
750: if (padlen < 4)
751: padlen += block_size;
1.71 markus 752: if (extra_pad) {
753: /* will wrap if extra_pad+padlen > 255 */
754: extra_pad = roundup(extra_pad, block_size);
755: pad = extra_pad - ((len + padlen) % extra_pad);
1.93 markus 756: debug3("packet_send2: adding %d (len %d padlen %d extra_pad %d)",
1.71 markus 757: pad, len, padlen, extra_pad);
758: padlen += pad;
759: extra_pad = 0;
760: }
1.76 stevesk 761: cp = buffer_append_space(&outgoing_packet, padlen);
1.88 markus 762: if (enc && !send_context.plaintext) {
1.32 markus 763: /* random padding */
1.25 markus 764: for (i = 0; i < padlen; i++) {
765: if (i % 4 == 0)
1.115 avsm 766: rnd = arc4random();
767: cp[i] = rnd & 0xff;
768: rnd >>= 8;
1.25 markus 769: }
1.32 markus 770: } else {
771: /* clear padding */
772: memset(cp, 0, padlen);
1.25 markus 773: }
774: /* packet_length includes payload, padding and padding length field */
775: packet_length = buffer_len(&outgoing_packet) - 4;
1.89 markus 776: cp = buffer_ptr(&outgoing_packet);
1.121.2.1! brad 777: put_u32(cp, packet_length);
1.89 markus 778: cp[4] = padlen;
1.25 markus 779: DBG(debug("send: len %d (includes padlen %d)", packet_length+4, padlen));
780:
781: /* compute MAC over seqnr and packet(length fields, payload, padding) */
782: if (mac && mac->enabled) {
1.105 markus 783: macbuf = mac_compute(mac, p_send.seqnr,
1.83 stevesk 784: buffer_ptr(&outgoing_packet),
1.50 markus 785: buffer_len(&outgoing_packet));
1.105 markus 786: DBG(debug("done calc MAC out #%d", p_send.seqnr));
1.25 markus 787: }
788: /* encrypt packet and append to output buffer. */
1.76 stevesk 789: cp = buffer_append_space(&output, buffer_len(&outgoing_packet));
1.88 markus 790: cipher_crypt(&send_context, cp, buffer_ptr(&outgoing_packet),
1.25 markus 791: buffer_len(&outgoing_packet));
792: /* append unencrypted MAC */
793: if (mac && mac->enabled)
1.121.2.1! brad 794: buffer_append(&output, macbuf, mac->mac_len);
1.25 markus 795: #ifdef PACKET_DEBUG
796: fprintf(stderr, "encrypted: ");
797: buffer_dump(&output);
798: #endif
1.29 markus 799: /* increment sequence number for outgoing packets */
1.105 markus 800: if (++p_send.seqnr == 0)
1.106 itojun 801: logit("outgoing seqnr wraps around");
1.105 markus 802: if (++p_send.packets == 0)
803: if (!(datafellows & SSH_BUG_NOREKEY))
804: fatal("XXX too many packets with same key");
805: p_send.blocks += (packet_length + 4) / block_size;
1.25 markus 806: buffer_clear(&outgoing_packet);
807:
1.57 markus 808: if (type == SSH2_MSG_NEWKEYS)
809: set_newkeys(MODE_OUT);
1.118 markus 810: else if (type == SSH2_MSG_USERAUTH_SUCCESS && server_side)
811: packet_enable_delayed_compress();
1.25 markus 812: }
813:
1.105 markus 814: static void
815: packet_send2(void)
816: {
817: static int rekeying = 0;
818: struct packet *p;
819: u_char type, *cp;
820:
821: cp = buffer_ptr(&outgoing_packet);
822: type = cp[5];
823:
824: /* during rekeying we can only send key exchange messages */
825: if (rekeying) {
826: if (!((type >= SSH2_MSG_TRANSPORT_MIN) &&
827: (type <= SSH2_MSG_TRANSPORT_MAX))) {
828: debug("enqueue packet: %u", type);
829: p = xmalloc(sizeof(*p));
830: p->type = type;
831: memcpy(&p->payload, &outgoing_packet, sizeof(Buffer));
832: buffer_init(&outgoing_packet);
833: TAILQ_INSERT_TAIL(&outgoing, p, next);
834: return;
835: }
836: }
837:
838: /* rekeying starts with sending KEXINIT */
839: if (type == SSH2_MSG_KEXINIT)
840: rekeying = 1;
841:
842: packet_send2_wrapped();
843:
844: /* after a NEWKEYS message we can send the complete queue */
845: if (type == SSH2_MSG_NEWKEYS) {
846: rekeying = 0;
847: while ((p = TAILQ_FIRST(&outgoing))) {
848: type = p->type;
849: debug("dequeue packet: %u", type);
850: buffer_free(&outgoing_packet);
851: memcpy(&outgoing_packet, &p->payload,
852: sizeof(Buffer));
853: TAILQ_REMOVE(&outgoing, p, next);
854: xfree(p);
855: packet_send2_wrapped();
856: }
857: }
858: }
859:
1.25 markus 860: void
1.73 itojun 861: packet_send(void)
1.25 markus 862: {
1.62 markus 863: if (compat20)
1.25 markus 864: packet_send2();
865: else
866: packet_send1();
867: DBG(debug("packet_send done"));
868: }
869:
870: /*
1.16 markus 871: * Waits until a packet has been received, and returns its type. Note that
872: * no other data is processed until this returns, so this function should not
873: * be used during the interactive session.
874: */
1.1 deraadt 875:
1.2 provos 876: int
1.82 markus 877: packet_read_seqnr(u_int32_t *seqnr_p)
1.1 deraadt 878: {
1.14 markus 879: int type, len;
1.56 millert 880: fd_set *setp;
1.14 markus 881: char buf[8192];
1.25 markus 882: DBG(debug("packet_read()"));
1.14 markus 883:
1.121.2.1! brad 884: setp = (fd_set *)xcalloc(howmany(connection_in+1, NFDBITS),
1.56 millert 885: sizeof(fd_mask));
886:
1.14 markus 887: /* Since we are blocking, ensure that all written packets have been sent. */
888: packet_write_wait();
889:
890: /* Stay in the loop until we have received a complete packet. */
891: for (;;) {
892: /* Try to read a packet from the buffer. */
1.82 markus 893: type = packet_read_poll_seqnr(seqnr_p);
1.62 markus 894: if (!compat20 && (
1.32 markus 895: type == SSH_SMSG_SUCCESS
1.14 markus 896: || type == SSH_SMSG_FAILURE
897: || type == SSH_CMSG_EOF
1.32 markus 898: || type == SSH_CMSG_EXIT_CONFIRMATION))
1.79 markus 899: packet_check_eom();
1.14 markus 900: /* If we got a packet, return it. */
1.56 millert 901: if (type != SSH_MSG_NONE) {
902: xfree(setp);
1.14 markus 903: return type;
1.56 millert 904: }
1.16 markus 905: /*
906: * Otherwise, wait for some data to arrive, add it to the
907: * buffer, and try again.
908: */
1.56 millert 909: memset(setp, 0, howmany(connection_in + 1, NFDBITS) *
910: sizeof(fd_mask));
911: FD_SET(connection_in, setp);
1.16 markus 912:
1.14 markus 913: /* Wait for some data to arrive. */
1.56 millert 914: while (select(connection_in + 1, setp, NULL, NULL, NULL) == -1 &&
1.51 deraadt 915: (errno == EAGAIN || errno == EINTR))
916: ;
1.16 markus 917:
1.14 markus 918: /* Read data from the socket. */
919: len = read(connection_in, buf, sizeof(buf));
1.18 markus 920: if (len == 0) {
1.106 itojun 921: logit("Connection closed by %.200s", get_remote_ipaddr());
1.112 markus 922: cleanup_exit(255);
1.18 markus 923: }
1.14 markus 924: if (len < 0)
925: fatal("Read from socket failed: %.100s", strerror(errno));
926: /* Append it to the buffer. */
927: packet_process_incoming(buf, len);
928: }
929: /* NOTREACHED */
1.1 deraadt 930: }
931:
1.77 djm 932: int
1.82 markus 933: packet_read(void)
1.77 djm 934: {
1.82 markus 935: return packet_read_seqnr(NULL);
1.77 djm 936: }
937:
1.16 markus 938: /*
939: * Waits until a packet has been received, verifies that its type matches
940: * that given, and gives a fatal error and exits if there is a mismatch.
941: */
1.1 deraadt 942:
1.2 provos 943: void
1.82 markus 944: packet_read_expect(int expected_type)
1.1 deraadt 945: {
1.14 markus 946: int type;
1.1 deraadt 947:
1.82 markus 948: type = packet_read();
1.14 markus 949: if (type != expected_type)
950: packet_disconnect("Protocol error: expected packet type %d, got %d",
1.25 markus 951: expected_type, type);
1.1 deraadt 952: }
953:
954: /* Checks if a full packet is available in the data received so far via
1.14 markus 955: * packet_process_incoming. If so, reads the packet; otherwise returns
956: * SSH_MSG_NONE. This does not wait for data from the connection.
957: *
958: * SSH_MSG_DISCONNECT is handled specially here. Also,
959: * SSH_MSG_IGNORE messages are skipped by this function and are never returned
960: * to higher levels.
961: */
1.1 deraadt 962:
1.68 itojun 963: static int
1.82 markus 964: packet_read_poll1(void)
1.1 deraadt 965: {
1.40 markus 966: u_int len, padded_len;
1.89 markus 967: u_char *cp, type;
1.40 markus 968: u_int checksum, stored_checksum;
1.14 markus 969:
970: /* Check if input size is less than minimum packet size. */
971: if (buffer_len(&input) < 4 + 8)
972: return SSH_MSG_NONE;
973: /* Get length of incoming packet. */
1.89 markus 974: cp = buffer_ptr(&input);
1.121.2.1! brad 975: len = get_u32(cp);
1.14 markus 976: if (len < 1 + 2 + 2 || len > 256 * 1024)
1.98 markus 977: packet_disconnect("Bad packet length %u.", len);
1.14 markus 978: padded_len = (len + 8) & ~7;
979:
980: /* Check if the packet has been entirely received. */
981: if (buffer_len(&input) < 4 + padded_len)
982: return SSH_MSG_NONE;
983:
984: /* The entire packet is in buffer. */
985:
986: /* Consume packet length. */
987: buffer_consume(&input, 4);
988:
1.62 markus 989: /*
990: * Cryptographic attack detector for ssh
991: * (C)1998 CORE-SDI, Buenos Aires Argentina
992: * Ariel Futoransky(futo@core-sdi.com)
993: */
1.121.2.1! brad 994: if (!receive_context.plaintext) {
! 995: switch (detect_attack(buffer_ptr(&input), padded_len)) {
! 996: case DEATTACK_DETECTED:
! 997: packet_disconnect("crc32 compensation attack: "
! 998: "network attack detected");
! 999: case DEATTACK_DOS_DETECTED:
! 1000: packet_disconnect("deattack denial of "
! 1001: "service detected");
! 1002: }
! 1003: }
1.62 markus 1004:
1005: /* Decrypt data to incoming_packet. */
1.14 markus 1006: buffer_clear(&incoming_packet);
1.76 stevesk 1007: cp = buffer_append_space(&incoming_packet, padded_len);
1.88 markus 1008: cipher_crypt(&receive_context, cp, buffer_ptr(&input), padded_len);
1.62 markus 1009:
1.14 markus 1010: buffer_consume(&input, padded_len);
1.1 deraadt 1011:
1012: #ifdef PACKET_DEBUG
1.14 markus 1013: fprintf(stderr, "read_poll plain: ");
1014: buffer_dump(&incoming_packet);
1.1 deraadt 1015: #endif
1016:
1.14 markus 1017: /* Compute packet checksum. */
1.83 stevesk 1018: checksum = ssh_crc32(buffer_ptr(&incoming_packet),
1.25 markus 1019: buffer_len(&incoming_packet) - 4);
1.14 markus 1020:
1021: /* Skip padding. */
1022: buffer_consume(&incoming_packet, 8 - len % 8);
1023:
1024: /* Test check bytes. */
1025: if (len != buffer_len(&incoming_packet))
1.77 djm 1026: packet_disconnect("packet_read_poll1: len %d != buffer_len %d.",
1.25 markus 1027: len, buffer_len(&incoming_packet));
1.14 markus 1028:
1.89 markus 1029: cp = (u_char *)buffer_ptr(&incoming_packet) + len - 4;
1.121.2.1! brad 1030: stored_checksum = get_u32(cp);
1.14 markus 1031: if (checksum != stored_checksum)
1032: packet_disconnect("Corrupted check bytes on input.");
1033: buffer_consume_end(&incoming_packet, 4);
1034:
1035: if (packet_compression) {
1036: buffer_clear(&compression_buffer);
1037: buffer_uncompress(&incoming_packet, &compression_buffer);
1038: buffer_clear(&incoming_packet);
1039: buffer_append(&incoming_packet, buffer_ptr(&compression_buffer),
1.25 markus 1040: buffer_len(&compression_buffer));
1.14 markus 1041: }
1.62 markus 1042: type = buffer_get_char(&incoming_packet);
1.116 markus 1043: if (type < SSH_MSG_MIN || type > SSH_MSG_MAX)
1044: packet_disconnect("Invalid ssh1 packet type: %d", type);
1.62 markus 1045: return type;
1.1 deraadt 1046: }
1.14 markus 1047:
1.68 itojun 1048: static int
1.82 markus 1049: packet_read_poll2(u_int32_t *seqnr_p)
1.25 markus 1050: {
1.50 markus 1051: static u_int packet_length = 0;
1.40 markus 1052: u_int padlen, need;
1.89 markus 1053: u_char *macbuf, *cp, type;
1.117 djm 1054: u_int maclen, block_size;
1.25 markus 1055: Enc *enc = NULL;
1056: Mac *mac = NULL;
1057: Comp *comp = NULL;
1058:
1.57 markus 1059: if (newkeys[MODE_IN] != NULL) {
1060: enc = &newkeys[MODE_IN]->enc;
1061: mac = &newkeys[MODE_IN]->mac;
1062: comp = &newkeys[MODE_IN]->comp;
1.25 markus 1063: }
1064: maclen = mac && mac->enabled ? mac->mac_len : 0;
1.88 markus 1065: block_size = enc ? enc->block_size : 8;
1.25 markus 1066:
1067: if (packet_length == 0) {
1068: /*
1069: * check if input size is less than the cipher block size,
1070: * decrypt first block and extract length of incoming packet
1071: */
1072: if (buffer_len(&input) < block_size)
1073: return SSH_MSG_NONE;
1074: buffer_clear(&incoming_packet);
1.76 stevesk 1075: cp = buffer_append_space(&incoming_packet, block_size);
1.88 markus 1076: cipher_crypt(&receive_context, cp, buffer_ptr(&input),
1.25 markus 1077: block_size);
1.89 markus 1078: cp = buffer_ptr(&incoming_packet);
1.121.2.1! brad 1079: packet_length = get_u32(cp);
1.25 markus 1080: if (packet_length < 1 + 4 || packet_length > 256 * 1024) {
1.110 markus 1081: #ifdef PACKET_DEBUG
1.25 markus 1082: buffer_dump(&incoming_packet);
1.110 markus 1083: #endif
1.98 markus 1084: packet_disconnect("Bad packet length %u.", packet_length);
1.25 markus 1085: }
1.98 markus 1086: DBG(debug("input: packet len %u", packet_length+4));
1.25 markus 1087: buffer_consume(&input, block_size);
1088: }
1089: /* we have a partial packet of block_size bytes */
1090: need = 4 + packet_length - block_size;
1091: DBG(debug("partial packet %d, need %d, maclen %d", block_size,
1092: need, maclen));
1093: if (need % block_size != 0)
1094: fatal("padding error: need %d block %d mod %d",
1095: need, block_size, need % block_size);
1096: /*
1097: * check if the entire packet has been received and
1098: * decrypt into incoming_packet
1099: */
1100: if (buffer_len(&input) < need + maclen)
1101: return SSH_MSG_NONE;
1102: #ifdef PACKET_DEBUG
1103: fprintf(stderr, "read_poll enc/full: ");
1104: buffer_dump(&input);
1105: #endif
1.76 stevesk 1106: cp = buffer_append_space(&incoming_packet, need);
1.88 markus 1107: cipher_crypt(&receive_context, cp, buffer_ptr(&input), need);
1.25 markus 1108: buffer_consume(&input, need);
1109: /*
1110: * compute MAC over seqnr and packet,
1111: * increment sequence number for incoming packet
1112: */
1.29 markus 1113: if (mac && mac->enabled) {
1.105 markus 1114: macbuf = mac_compute(mac, p_read.seqnr,
1.83 stevesk 1115: buffer_ptr(&incoming_packet),
1.50 markus 1116: buffer_len(&incoming_packet));
1.25 markus 1117: if (memcmp(macbuf, buffer_ptr(&input), mac->mac_len) != 0)
1.36 markus 1118: packet_disconnect("Corrupted MAC on input.");
1.105 markus 1119: DBG(debug("MAC #%d ok", p_read.seqnr));
1.25 markus 1120: buffer_consume(&input, mac->mac_len);
1121: }
1.77 djm 1122: if (seqnr_p != NULL)
1.105 markus 1123: *seqnr_p = p_read.seqnr;
1124: if (++p_read.seqnr == 0)
1.106 itojun 1125: logit("incoming seqnr wraps around");
1.105 markus 1126: if (++p_read.packets == 0)
1127: if (!(datafellows & SSH_BUG_NOREKEY))
1128: fatal("XXX too many packets with same key");
1129: p_read.blocks += (packet_length + 4) / block_size;
1.25 markus 1130:
1131: /* get padlen */
1.76 stevesk 1132: cp = buffer_ptr(&incoming_packet);
1.89 markus 1133: padlen = cp[4];
1.25 markus 1134: DBG(debug("input: padlen %d", padlen));
1135: if (padlen < 4)
1136: packet_disconnect("Corrupted padlen %d on input.", padlen);
1137:
1138: /* skip packet size + padlen, discard padding */
1139: buffer_consume(&incoming_packet, 4 + 1);
1140: buffer_consume_end(&incoming_packet, padlen);
1141:
1142: DBG(debug("input: len before de-compress %d", buffer_len(&incoming_packet)));
1143: if (comp && comp->enabled) {
1144: buffer_clear(&compression_buffer);
1145: buffer_uncompress(&incoming_packet, &compression_buffer);
1146: buffer_clear(&incoming_packet);
1147: buffer_append(&incoming_packet, buffer_ptr(&compression_buffer),
1148: buffer_len(&compression_buffer));
1.97 deraadt 1149: DBG(debug("input: len after de-compress %d",
1150: buffer_len(&incoming_packet)));
1.25 markus 1151: }
1152: /*
1153: * get packet type, implies consume.
1154: * return length of payload (without type field)
1155: */
1.62 markus 1156: type = buffer_get_char(&incoming_packet);
1.116 markus 1157: if (type < SSH2_MSG_MIN || type >= SSH2_MSG_LOCAL_MIN)
1158: packet_disconnect("Invalid ssh2 packet type: %d", type);
1.57 markus 1159: if (type == SSH2_MSG_NEWKEYS)
1160: set_newkeys(MODE_IN);
1.118 markus 1161: else if (type == SSH2_MSG_USERAUTH_SUCCESS && !server_side)
1162: packet_enable_delayed_compress();
1.25 markus 1163: #ifdef PACKET_DEBUG
1.55 deraadt 1164: fprintf(stderr, "read/plain[%d]:\r\n", type);
1.25 markus 1165: buffer_dump(&incoming_packet);
1166: #endif
1.62 markus 1167: /* reset for next packet */
1168: packet_length = 0;
1169: return type;
1.25 markus 1170: }
1171:
1172: int
1.82 markus 1173: packet_read_poll_seqnr(u_int32_t *seqnr_p)
1.25 markus 1174: {
1.96 deraadt 1175: u_int reason, seqnr;
1.62 markus 1176: u_char type;
1.25 markus 1177: char *msg;
1.62 markus 1178:
1.25 markus 1179: for (;;) {
1.62 markus 1180: if (compat20) {
1.82 markus 1181: type = packet_read_poll2(seqnr_p);
1.62 markus 1182: if (type)
1.25 markus 1183: DBG(debug("received packet type %d", type));
1.74 deraadt 1184: switch (type) {
1.25 markus 1185: case SSH2_MSG_IGNORE:
1186: break;
1187: case SSH2_MSG_DEBUG:
1188: packet_get_char();
1189: msg = packet_get_string(NULL);
1190: debug("Remote: %.900s", msg);
1191: xfree(msg);
1192: msg = packet_get_string(NULL);
1193: xfree(msg);
1194: break;
1195: case SSH2_MSG_DISCONNECT:
1196: reason = packet_get_int();
1197: msg = packet_get_string(NULL);
1.106 itojun 1198: logit("Received disconnect from %s: %u: %.400s",
1.96 deraadt 1199: get_remote_ipaddr(), reason, msg);
1.25 markus 1200: xfree(msg);
1.112 markus 1201: cleanup_exit(255);
1.84 markus 1202: break;
1203: case SSH2_MSG_UNIMPLEMENTED:
1204: seqnr = packet_get_int();
1.96 deraadt 1205: debug("Received SSH2_MSG_UNIMPLEMENTED for %u",
1206: seqnr);
1.25 markus 1207: break;
1208: default:
1209: return type;
1.48 stevesk 1210: }
1.25 markus 1211: } else {
1.82 markus 1212: type = packet_read_poll1();
1.74 deraadt 1213: switch (type) {
1.25 markus 1214: case SSH_MSG_IGNORE:
1215: break;
1216: case SSH_MSG_DEBUG:
1217: msg = packet_get_string(NULL);
1218: debug("Remote: %.900s", msg);
1219: xfree(msg);
1220: break;
1221: case SSH_MSG_DISCONNECT:
1222: msg = packet_get_string(NULL);
1.106 itojun 1223: logit("Received disconnect from %s: %.400s",
1.96 deraadt 1224: get_remote_ipaddr(), msg);
1.112 markus 1225: cleanup_exit(255);
1.25 markus 1226: xfree(msg);
1227: break;
1228: default:
1.62 markus 1229: if (type)
1.25 markus 1230: DBG(debug("received packet type %d", type));
1231: return type;
1.48 stevesk 1232: }
1.25 markus 1233: }
1234: }
1.77 djm 1235: }
1236:
1237: int
1.82 markus 1238: packet_read_poll(void)
1.77 djm 1239: {
1.82 markus 1240: return packet_read_poll_seqnr(NULL);
1.25 markus 1241: }
1242:
1.16 markus 1243: /*
1244: * Buffers the given amount of input characters. This is intended to be used
1245: * together with packet_read_poll.
1246: */
1.1 deraadt 1247:
1.2 provos 1248: void
1.40 markus 1249: packet_process_incoming(const char *buf, u_int len)
1.1 deraadt 1250: {
1.14 markus 1251: buffer_append(&input, buf, len);
1.1 deraadt 1252: }
1253:
1254: /* Returns a character from the packet. */
1255:
1.40 markus 1256: u_int
1.73 itojun 1257: packet_get_char(void)
1.1 deraadt 1258: {
1.14 markus 1259: char ch;
1.97 deraadt 1260:
1.14 markus 1261: buffer_get(&incoming_packet, &ch, 1);
1.40 markus 1262: return (u_char) ch;
1.1 deraadt 1263: }
1264:
1265: /* Returns an integer from the packet data. */
1266:
1.40 markus 1267: u_int
1.73 itojun 1268: packet_get_int(void)
1.1 deraadt 1269: {
1.14 markus 1270: return buffer_get_int(&incoming_packet);
1.1 deraadt 1271: }
1272:
1.16 markus 1273: /*
1274: * Returns an arbitrary precision integer from the packet data. The integer
1275: * must have been initialized before this call.
1276: */
1.1 deraadt 1277:
1.2 provos 1278: void
1.80 markus 1279: packet_get_bignum(BIGNUM * value)
1.1 deraadt 1280: {
1.81 markus 1281: buffer_get_bignum(&incoming_packet, value);
1.24 markus 1282: }
1283:
1284: void
1.80 markus 1285: packet_get_bignum2(BIGNUM * value)
1.24 markus 1286: {
1.81 markus 1287: buffer_get_bignum2(&incoming_packet, value);
1.24 markus 1288: }
1289:
1.76 stevesk 1290: void *
1.117 djm 1291: packet_get_raw(u_int *length_ptr)
1.24 markus 1292: {
1.117 djm 1293: u_int bytes = buffer_len(&incoming_packet);
1.97 deraadt 1294:
1.24 markus 1295: if (length_ptr != NULL)
1296: *length_ptr = bytes;
1297: return buffer_ptr(&incoming_packet);
1.28 markus 1298: }
1299:
1300: int
1301: packet_remaining(void)
1302: {
1303: return buffer_len(&incoming_packet);
1.1 deraadt 1304: }
1305:
1.16 markus 1306: /*
1307: * Returns a string from the packet data. The string is allocated using
1308: * xmalloc; it is the responsibility of the calling program to free it when
1309: * no longer needed. The length_ptr argument may be NULL, or point to an
1310: * integer into which the length of the string is stored.
1311: */
1.1 deraadt 1312:
1.76 stevesk 1313: void *
1.40 markus 1314: packet_get_string(u_int *length_ptr)
1.1 deraadt 1315: {
1.14 markus 1316: return buffer_get_string(&incoming_packet, length_ptr);
1.1 deraadt 1317: }
1318:
1.16 markus 1319: /*
1320: * Sends a diagnostic message from the server to the client. This message
1321: * can be sent at any time (but not while constructing another message). The
1322: * message is printed immediately, but only if the client is being executed
1323: * in verbose mode. These messages are primarily intended to ease debugging
1324: * authentication problems. The length of the formatted message must not
1325: * exceed 1024 bytes. This will automatically call packet_write_wait.
1326: */
1.1 deraadt 1327:
1.2 provos 1328: void
1.14 markus 1329: packet_send_debug(const char *fmt,...)
1.1 deraadt 1330: {
1.14 markus 1331: char buf[1024];
1332: va_list args;
1.39 markus 1333:
1334: if (compat20 && (datafellows & SSH_BUG_DEBUG))
1335: return;
1.14 markus 1336:
1337: va_start(args, fmt);
1338: vsnprintf(buf, sizeof(buf), fmt, args);
1339: va_end(args);
1340:
1.30 markus 1341: if (compat20) {
1342: packet_start(SSH2_MSG_DEBUG);
1343: packet_put_char(0); /* bool: always display */
1344: packet_put_cstring(buf);
1345: packet_put_cstring("");
1346: } else {
1347: packet_start(SSH_MSG_DEBUG);
1348: packet_put_cstring(buf);
1349: }
1.14 markus 1350: packet_send();
1351: packet_write_wait();
1.1 deraadt 1352: }
1353:
1.16 markus 1354: /*
1355: * Logs the error plus constructs and sends a disconnect packet, closes the
1356: * connection, and exits. This function never returns. The error message
1357: * should not contain a newline. The length of the formatted message must
1358: * not exceed 1024 bytes.
1359: */
1.1 deraadt 1360:
1.2 provos 1361: void
1.14 markus 1362: packet_disconnect(const char *fmt,...)
1.1 deraadt 1363: {
1.14 markus 1364: char buf[1024];
1365: va_list args;
1366: static int disconnecting = 0;
1.97 deraadt 1367:
1.14 markus 1368: if (disconnecting) /* Guard against recursive invocations. */
1369: fatal("packet_disconnect called recursively.");
1370: disconnecting = 1;
1371:
1.16 markus 1372: /*
1373: * Format the message. Note that the caller must make sure the
1374: * message is of limited size.
1375: */
1.14 markus 1376: va_start(args, fmt);
1377: vsnprintf(buf, sizeof(buf), fmt, args);
1378: va_end(args);
1379:
1.99 markus 1380: /* Display the error locally */
1.106 itojun 1381: logit("Disconnecting: %.100s", buf);
1.99 markus 1382:
1.14 markus 1383: /* Send the disconnect message to the other side, and wait for it to get sent. */
1.25 markus 1384: if (compat20) {
1385: packet_start(SSH2_MSG_DISCONNECT);
1386: packet_put_int(SSH2_DISCONNECT_PROTOCOL_ERROR);
1387: packet_put_cstring(buf);
1388: packet_put_cstring("");
1389: } else {
1390: packet_start(SSH_MSG_DISCONNECT);
1.65 markus 1391: packet_put_cstring(buf);
1.25 markus 1392: }
1.14 markus 1393: packet_send();
1394: packet_write_wait();
1395:
1396: /* Stop listening for connections. */
1.67 markus 1397: channel_close_all();
1.14 markus 1398:
1399: /* Close the connection. */
1400: packet_close();
1.112 markus 1401: cleanup_exit(255);
1.1 deraadt 1402: }
1403:
1.16 markus 1404: /* Checks if there is any buffered output, and tries to write some of the output. */
1.1 deraadt 1405:
1.2 provos 1406: void
1.73 itojun 1407: packet_write_poll(void)
1.1 deraadt 1408: {
1.14 markus 1409: int len = buffer_len(&output);
1.97 deraadt 1410:
1.14 markus 1411: if (len > 0) {
1412: len = write(connection_out, buffer_ptr(&output), len);
1413: if (len <= 0) {
1414: if (errno == EAGAIN)
1415: return;
1416: else
1417: fatal("Write failed: %.100s", strerror(errno));
1418: }
1419: buffer_consume(&output, len);
1420: }
1.1 deraadt 1421: }
1422:
1.16 markus 1423: /*
1424: * Calls packet_write_poll repeatedly until all pending output data has been
1425: * written.
1426: */
1.1 deraadt 1427:
1.2 provos 1428: void
1.73 itojun 1429: packet_write_wait(void)
1.1 deraadt 1430: {
1.56 millert 1431: fd_set *setp;
1432:
1.121.2.1! brad 1433: setp = (fd_set *)xcalloc(howmany(connection_out + 1, NFDBITS),
1.56 millert 1434: sizeof(fd_mask));
1.14 markus 1435: packet_write_poll();
1436: while (packet_have_data_to_write()) {
1.56 millert 1437: memset(setp, 0, howmany(connection_out + 1, NFDBITS) *
1438: sizeof(fd_mask));
1439: FD_SET(connection_out, setp);
1440: while (select(connection_out + 1, NULL, setp, NULL, NULL) == -1 &&
1.51 deraadt 1441: (errno == EAGAIN || errno == EINTR))
1442: ;
1.14 markus 1443: packet_write_poll();
1444: }
1.56 millert 1445: xfree(setp);
1.1 deraadt 1446: }
1447:
1448: /* Returns true if there is buffered data to write to the connection. */
1449:
1.2 provos 1450: int
1.73 itojun 1451: packet_have_data_to_write(void)
1.1 deraadt 1452: {
1.14 markus 1453: return buffer_len(&output) != 0;
1.1 deraadt 1454: }
1455:
1456: /* Returns true if there is not too much data to write to the connection. */
1457:
1.2 provos 1458: int
1.73 itojun 1459: packet_not_very_much_data_to_write(void)
1.1 deraadt 1460: {
1.14 markus 1461: if (interactive_mode)
1462: return buffer_len(&output) < 16384;
1463: else
1464: return buffer_len(&output) < 128 * 1024;
1.1 deraadt 1465: }
1466:
1.102 markus 1467: static void
1.101 markus 1468: packet_set_tos(int interactive)
1469: {
1470: int tos = interactive ? IPTOS_LOWDELAY : IPTOS_THROUGHPUT;
1471:
1472: if (!packet_connection_is_on_socket() ||
1473: !packet_connection_is_ipv4())
1474: return;
1475: if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, &tos,
1476: sizeof(tos)) < 0)
1477: error("setsockopt IP_TOS %d: %.100s:",
1478: tos, strerror(errno));
1479: }
1480:
1.1 deraadt 1481: /* Informs that the current session is interactive. Sets IP flags for that. */
1482:
1.2 provos 1483: void
1.43 markus 1484: packet_set_interactive(int interactive)
1.1 deraadt 1485: {
1.43 markus 1486: static int called = 0;
1.44 markus 1487:
1.43 markus 1488: if (called)
1489: return;
1490: called = 1;
1.1 deraadt 1491:
1.14 markus 1492: /* Record that we are in interactive mode. */
1493: interactive_mode = interactive;
1.1 deraadt 1494:
1.19 markus 1495: /* Only set socket options if using a socket. */
1496: if (!packet_connection_is_on_socket())
1.14 markus 1497: return;
1.121.2.1! brad 1498: set_nodelay(connection_in);
1.101 markus 1499: packet_set_tos(interactive);
1.1 deraadt 1500: }
1501:
1502: /* Returns true if the current connection is interactive. */
1503:
1.2 provos 1504: int
1.73 itojun 1505: packet_is_interactive(void)
1.1 deraadt 1506: {
1.14 markus 1507: return interactive_mode;
1.12 markus 1508: }
1509:
1.113 deraadt 1510: int
1.108 markus 1511: packet_set_maxsize(u_int s)
1.12 markus 1512: {
1.14 markus 1513: static int called = 0;
1.97 deraadt 1514:
1.14 markus 1515: if (called) {
1.106 itojun 1516: logit("packet_set_maxsize: called twice: old %d new %d",
1.25 markus 1517: max_packet_size, s);
1.14 markus 1518: return -1;
1519: }
1520: if (s < 4 * 1024 || s > 1024 * 1024) {
1.106 itojun 1521: logit("packet_set_maxsize: bad size %d", s);
1.14 markus 1522: return -1;
1523: }
1.70 markus 1524: called = 1;
1.66 markus 1525: debug("packet_set_maxsize: setting to %d", s);
1.14 markus 1526: max_packet_size = s;
1527: return s;
1.53 markus 1528: }
1529:
1.71 markus 1530: /* roundup current message to pad bytes */
1531: void
1532: packet_add_padding(u_char pad)
1533: {
1534: extra_pad = pad;
1535: }
1536:
1.53 markus 1537: /*
1538: * 9.2. Ignored Data Message
1.61 markus 1539: *
1.53 markus 1540: * byte SSH_MSG_IGNORE
1541: * string data
1.61 markus 1542: *
1.53 markus 1543: * All implementations MUST understand (and ignore) this message at any
1544: * time (after receiving the protocol version). No implementation is
1545: * required to send them. This message can be used as an additional
1546: * protection measure against advanced traffic analysis techniques.
1547: */
1.54 markus 1548: void
1549: packet_send_ignore(int nbytes)
1550: {
1.115 avsm 1551: u_int32_t rnd = 0;
1.54 markus 1552: int i;
1553:
1554: packet_start(compat20 ? SSH2_MSG_IGNORE : SSH_MSG_IGNORE);
1.53 markus 1555: packet_put_int(nbytes);
1.75 deraadt 1556: for (i = 0; i < nbytes; i++) {
1.53 markus 1557: if (i % 4 == 0)
1.115 avsm 1558: rnd = arc4random();
1.121.2.1! brad 1559: packet_put_char((u_char)rnd & 0xff);
1.115 avsm 1560: rnd >>= 8;
1.53 markus 1561: }
1.105 markus 1562: }
1563:
1.113 deraadt 1564: #define MAX_PACKETS (1U<<31)
1.105 markus 1565: int
1566: packet_need_rekeying(void)
1567: {
1568: if (datafellows & SSH_BUG_NOREKEY)
1569: return 0;
1570: return
1571: (p_send.packets > MAX_PACKETS) ||
1572: (p_read.packets > MAX_PACKETS) ||
1573: (max_blocks_out && (p_send.blocks > max_blocks_out)) ||
1574: (max_blocks_in && (p_read.blocks > max_blocks_in));
1575: }
1576:
1577: void
1578: packet_set_rekey_limit(u_int32_t bytes)
1579: {
1580: rekey_limit = bytes;
1.118 markus 1581: }
1582:
1583: void
1584: packet_set_server(void)
1585: {
1586: server_side = 1;
1587: }
1588:
1589: void
1590: packet_set_authenticated(void)
1591: {
1592: after_authentication = 1;
1.1 deraadt 1593: }
![[BACK]](/icons/back.gif){kind=icon}
Return to packet.c CVS log ![[TXT]](/icons/text.gif){kind=icon}
![[DIR]](/icons/dir.gif){kind=icon}
Up to [local] / src / usr.bin / ssh