Annotation of src/usr.bin/ssh/packet.c, Revision 1.136
1.136 ! stevesk 1: /* $OpenBSD: packet.c,v 1.135 2006/07/11 20:07:25 stevesk 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:
40: #include "includes.h"
1.105 markus 41:
42: #include <sys/queue.h>
1.133 stevesk 43: #include <sys/types.h>
1.132 stevesk 44: #include <sys/socket.h>
1.121 stevesk 45:
46: #include <netinet/in_systm.h>
1.132 stevesk 47: #include <netinet/in.h>
1.121 stevesk 48: #include <netinet/ip.h>
1.134 stevesk 49:
1.135 stevesk 50: #include <errno.h>
1.134 stevesk 51: #include <stdarg.h>
1.136 ! stevesk 52: #include <unistd.h>
1.1 deraadt 53:
54: #include "xmalloc.h"
55: #include "buffer.h"
56: #include "packet.h"
57: #include "bufaux.h"
58: #include "crc32.h"
59:
60: #include "compress.h"
1.9 dugsong 61: #include "deattack.h"
1.64 markus 62: #include "channels.h"
1.1 deraadt 63:
1.25 markus 64: #include "compat.h"
1.45 markus 65: #include "ssh1.h"
1.25 markus 66: #include "ssh2.h"
67:
1.37 markus 68: #include "cipher.h"
1.25 markus 69: #include "kex.h"
1.50 markus 70: #include "mac.h"
1.46 markus 71: #include "log.h"
72: #include "canohost.h"
1.87 stevesk 73: #include "misc.h"
1.95 markus 74: #include "ssh.h"
1.25 markus 75:
76: #ifdef PACKET_DEBUG
77: #define DBG(x) x
78: #else
79: #define DBG(x)
80: #endif
81:
1.16 markus 82: /*
83: * This variable contains the file descriptors used for communicating with
84: * the other side. connection_in is used for reading; connection_out for
85: * writing. These can be the same descriptor, in which case it is assumed to
86: * be a socket.
87: */
1.1 deraadt 88: static int connection_in = -1;
89: static int connection_out = -1;
90:
91: /* Protocol flags for the remote side. */
1.40 markus 92: static u_int remote_protocol_flags = 0;
1.1 deraadt 93:
94: /* Encryption context for receiving data. This is only used for decryption. */
95: static CipherContext receive_context;
1.14 markus 96:
97: /* Encryption context for sending data. This is only used for encryption. */
1.1 deraadt 98: static CipherContext send_context;
99:
100: /* Buffer for raw input data from the socket. */
1.91 markus 101: Buffer input;
1.1 deraadt 102:
103: /* Buffer for raw output data going to the socket. */
1.91 markus 104: Buffer output;
1.1 deraadt 105:
106: /* Buffer for the partial outgoing packet being constructed. */
107: static Buffer outgoing_packet;
108:
109: /* Buffer for the incoming packet currently being processed. */
110: static Buffer incoming_packet;
111:
112: /* Scratch buffer for packet compression/decompression. */
113: static Buffer compression_buffer;
1.60 markus 114: static int compression_buffer_ready = 0;
1.1 deraadt 115:
116: /* Flag indicating whether packet compression/decompression is enabled. */
117: static int packet_compression = 0;
118:
1.12 markus 119: /* default maximum packet size */
1.108 markus 120: u_int max_packet_size = 32768;
1.12 markus 121:
1.1 deraadt 122: /* Flag indicating whether this module has been initialized. */
123: static int initialized = 0;
124:
125: /* Set to true if the connection is interactive. */
126: static int interactive_mode = 0;
127:
1.118 markus 128: /* Set to true if we are the server side. */
129: static int server_side = 0;
130:
131: /* Set to true if we are authenticated. */
132: static int after_authentication = 0;
133:
1.25 markus 134: /* Session key information for Encryption and MAC */
1.57 markus 135: Newkeys *newkeys[MODE_MAX];
1.105 markus 136: static struct packet_state {
137: u_int32_t seqnr;
138: u_int32_t packets;
139: u_int64_t blocks;
140: } p_read, p_send;
141:
142: static u_int64_t max_blocks_in, max_blocks_out;
143: static u_int32_t rekey_limit;
1.25 markus 144:
1.95 markus 145: /* Session key for protocol v1 */
146: static u_char ssh1_key[SSH_SESSION_KEY_LENGTH];
147: static u_int ssh1_keylen;
148:
1.71 markus 149: /* roundup current message to extra_pad bytes */
150: static u_char extra_pad = 0;
151:
1.105 markus 152: struct packet {
153: TAILQ_ENTRY(packet) next;
154: u_char type;
155: Buffer payload;
156: };
157: TAILQ_HEAD(, packet) outgoing;
158:
1.16 markus 159: /*
160: * Sets the descriptors used for communication. Disables encryption until
161: * packet_set_encryption_key is called.
162: */
1.2 provos 163: void
164: packet_set_connection(int fd_in, int fd_out)
1.1 deraadt 165: {
1.37 markus 166: Cipher *none = cipher_by_name("none");
1.97 deraadt 167:
1.37 markus 168: if (none == NULL)
169: fatal("packet_set_connection: cannot load cipher 'none'");
1.14 markus 170: connection_in = fd_in;
171: connection_out = fd_out;
1.113 deraadt 172: cipher_init(&send_context, none, (const u_char *)"",
173: 0, NULL, 0, CIPHER_ENCRYPT);
174: cipher_init(&receive_context, none, (const u_char *)"",
175: 0, NULL, 0, CIPHER_DECRYPT);
1.62 markus 176: newkeys[MODE_IN] = newkeys[MODE_OUT] = NULL;
1.14 markus 177: if (!initialized) {
178: initialized = 1;
179: buffer_init(&input);
180: buffer_init(&output);
181: buffer_init(&outgoing_packet);
182: buffer_init(&incoming_packet);
1.105 markus 183: TAILQ_INIT(&outgoing);
1.14 markus 184: }
1.1 deraadt 185: }
186:
1.19 markus 187: /* Returns 1 if remote host is connected via socket, 0 if not. */
188:
189: int
1.73 itojun 190: packet_connection_is_on_socket(void)
1.19 markus 191: {
192: struct sockaddr_storage from, to;
193: socklen_t fromlen, tolen;
194:
195: /* filedescriptors in and out are the same, so it's a socket */
196: if (connection_in == connection_out)
197: return 1;
198: fromlen = sizeof(from);
199: memset(&from, 0, sizeof(from));
1.20 markus 200: if (getpeername(connection_in, (struct sockaddr *)&from, &fromlen) < 0)
1.19 markus 201: return 0;
202: tolen = sizeof(to);
203: memset(&to, 0, sizeof(to));
1.20 markus 204: if (getpeername(connection_out, (struct sockaddr *)&to, &tolen) < 0)
1.19 markus 205: return 0;
206: if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0)
207: return 0;
208: if (from.ss_family != AF_INET && from.ss_family != AF_INET6)
209: return 0;
210: return 1;
211: }
212:
1.92 markus 213: /*
1.91 markus 214: * Exports an IV from the CipherContext required to export the key
215: * state back from the unprivileged child to the privileged parent
216: * process.
217: */
218:
219: void
220: packet_get_keyiv(int mode, u_char *iv, u_int len)
221: {
222: CipherContext *cc;
223:
224: if (mode == MODE_OUT)
225: cc = &send_context;
226: else
227: cc = &receive_context;
228:
229: cipher_get_keyiv(cc, iv, len);
230: }
231:
232: int
233: packet_get_keycontext(int mode, u_char *dat)
234: {
235: CipherContext *cc;
1.92 markus 236:
1.91 markus 237: if (mode == MODE_OUT)
238: cc = &send_context;
239: else
240: cc = &receive_context;
241:
242: return (cipher_get_keycontext(cc, dat));
243: }
244:
245: void
246: packet_set_keycontext(int mode, u_char *dat)
247: {
248: CipherContext *cc;
1.92 markus 249:
1.91 markus 250: if (mode == MODE_OUT)
251: cc = &send_context;
252: else
253: cc = &receive_context;
254:
255: cipher_set_keycontext(cc, dat);
256: }
257:
258: int
259: packet_get_keyiv_len(int mode)
260: {
261: CipherContext *cc;
262:
263: if (mode == MODE_OUT)
264: cc = &send_context;
265: else
266: cc = &receive_context;
267:
268: return (cipher_get_keyiv_len(cc));
269: }
1.125 deraadt 270:
1.91 markus 271: void
272: packet_set_iv(int mode, u_char *dat)
273: {
274: CipherContext *cc;
275:
276: if (mode == MODE_OUT)
277: cc = &send_context;
278: else
279: cc = &receive_context;
280:
281: cipher_set_keyiv(cc, dat);
282: }
1.125 deraadt 283:
1.91 markus 284: int
1.107 deraadt 285: packet_get_ssh1_cipher(void)
1.91 markus 286: {
287: return (cipher_get_number(receive_context.cipher));
288: }
289:
1.105 markus 290: void
291: packet_get_state(int mode, u_int32_t *seqnr, u_int64_t *blocks, u_int32_t *packets)
292: {
293: struct packet_state *state;
1.104 markus 294:
1.105 markus 295: state = (mode == MODE_IN) ? &p_read : &p_send;
296: *seqnr = state->seqnr;
297: *blocks = state->blocks;
298: *packets = state->packets;
1.91 markus 299: }
300:
301: void
1.105 markus 302: packet_set_state(int mode, u_int32_t seqnr, u_int64_t blocks, u_int32_t packets)
1.91 markus 303: {
1.105 markus 304: struct packet_state *state;
305:
306: state = (mode == MODE_IN) ? &p_read : &p_send;
307: state->seqnr = seqnr;
308: state->blocks = blocks;
309: state->packets = packets;
1.91 markus 310: }
311:
1.19 markus 312: /* returns 1 if connection is via ipv4 */
313:
314: int
1.73 itojun 315: packet_connection_is_ipv4(void)
1.19 markus 316: {
317: struct sockaddr_storage to;
1.21 deraadt 318: socklen_t tolen = sizeof(to);
1.19 markus 319:
320: memset(&to, 0, sizeof(to));
321: if (getsockname(connection_out, (struct sockaddr *)&to, &tolen) < 0)
322: return 0;
323: if (to.ss_family != AF_INET)
324: return 0;
325: return 1;
326: }
327:
1.1 deraadt 328: /* Sets the connection into non-blocking mode. */
329:
1.2 provos 330: void
1.73 itojun 331: packet_set_nonblocking(void)
1.1 deraadt 332: {
1.14 markus 333: /* Set the socket into non-blocking mode. */
1.114 djm 334: set_nonblock(connection_in);
1.14 markus 335:
1.114 djm 336: if (connection_out != connection_in)
337: set_nonblock(connection_out);
1.1 deraadt 338: }
339:
340: /* Returns the socket used for reading. */
341:
1.2 provos 342: int
1.73 itojun 343: packet_get_connection_in(void)
1.1 deraadt 344: {
1.14 markus 345: return connection_in;
1.1 deraadt 346: }
347:
348: /* Returns the descriptor used for writing. */
349:
1.2 provos 350: int
1.73 itojun 351: packet_get_connection_out(void)
1.1 deraadt 352: {
1.14 markus 353: return connection_out;
1.1 deraadt 354: }
355:
356: /* Closes the connection and clears and frees internal data structures. */
357:
1.2 provos 358: void
1.73 itojun 359: packet_close(void)
1.1 deraadt 360: {
1.14 markus 361: if (!initialized)
362: return;
363: initialized = 0;
364: if (connection_in == connection_out) {
365: shutdown(connection_out, SHUT_RDWR);
366: close(connection_out);
367: } else {
368: close(connection_in);
369: close(connection_out);
370: }
371: buffer_free(&input);
372: buffer_free(&output);
373: buffer_free(&outgoing_packet);
374: buffer_free(&incoming_packet);
1.60 markus 375: if (compression_buffer_ready) {
1.14 markus 376: buffer_free(&compression_buffer);
377: buffer_compress_uninit();
378: }
1.88 markus 379: cipher_cleanup(&send_context);
380: cipher_cleanup(&receive_context);
1.1 deraadt 381: }
382:
383: /* Sets remote side protocol flags. */
384:
1.2 provos 385: void
1.40 markus 386: packet_set_protocol_flags(u_int protocol_flags)
1.1 deraadt 387: {
1.14 markus 388: remote_protocol_flags = protocol_flags;
1.1 deraadt 389: }
390:
391: /* Returns the remote protocol flags set earlier by the above function. */
392:
1.40 markus 393: u_int
1.73 itojun 394: packet_get_protocol_flags(void)
1.1 deraadt 395: {
1.14 markus 396: return remote_protocol_flags;
1.1 deraadt 397: }
398:
1.16 markus 399: /*
400: * Starts packet compression from the next packet on in both directions.
401: * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip.
402: */
1.1 deraadt 403:
1.68 itojun 404: static void
405: packet_init_compression(void)
1.60 markus 406: {
407: if (compression_buffer_ready == 1)
408: return;
409: compression_buffer_ready = 1;
410: buffer_init(&compression_buffer);
411: }
412:
1.2 provos 413: void
414: packet_start_compression(int level)
1.1 deraadt 415: {
1.62 markus 416: if (packet_compression && !compat20)
1.14 markus 417: fatal("Compression already enabled.");
418: packet_compression = 1;
1.60 markus 419: packet_init_compression();
420: buffer_compress_init_send(level);
421: buffer_compress_init_recv();
1.1 deraadt 422: }
423:
1.16 markus 424: /*
425: * Causes any further packets to be encrypted using the given key. The same
426: * key is used for both sending and reception. However, both directions are
427: * encrypted independently of each other.
428: */
1.95 markus 429:
1.2 provos 430: void
1.40 markus 431: packet_set_encryption_key(const u_char *key, u_int keylen,
1.37 markus 432: int number)
1.1 deraadt 433: {
1.37 markus 434: Cipher *cipher = cipher_by_number(number);
1.97 deraadt 435:
1.37 markus 436: if (cipher == NULL)
437: fatal("packet_set_encryption_key: unknown cipher number %d", number);
1.25 markus 438: if (keylen < 20)
1.37 markus 439: fatal("packet_set_encryption_key: keylen too small: %d", keylen);
1.95 markus 440: if (keylen > SSH_SESSION_KEY_LENGTH)
441: fatal("packet_set_encryption_key: keylen too big: %d", keylen);
442: memcpy(ssh1_key, key, keylen);
443: ssh1_keylen = keylen;
1.88 markus 444: cipher_init(&send_context, cipher, key, keylen, NULL, 0, CIPHER_ENCRYPT);
445: cipher_init(&receive_context, cipher, key, keylen, NULL, 0, CIPHER_DECRYPT);
1.95 markus 446: }
447:
448: u_int
449: packet_get_encryption_key(u_char *key)
450: {
451: if (key == NULL)
452: return (ssh1_keylen);
453: memcpy(key, ssh1_key, ssh1_keylen);
454: return (ssh1_keylen);
1.1 deraadt 455: }
456:
1.62 markus 457: /* Start constructing a packet to send. */
1.2 provos 458: void
1.62 markus 459: packet_start(u_char type)
1.1 deraadt 460: {
1.62 markus 461: u_char buf[9];
462: int len;
1.1 deraadt 463:
1.62 markus 464: DBG(debug("packet_start[%d]", type));
465: len = compat20 ? 6 : 9;
466: memset(buf, 0, len - 1);
467: buf[len - 1] = type;
1.14 markus 468: buffer_clear(&outgoing_packet);
1.62 markus 469: buffer_append(&outgoing_packet, buf, len);
1.25 markus 470: }
471:
1.62 markus 472: /* Append payload. */
1.2 provos 473: void
474: packet_put_char(int value)
1.1 deraadt 475: {
1.14 markus 476: char ch = value;
1.97 deraadt 477:
1.14 markus 478: buffer_append(&outgoing_packet, &ch, 1);
1.1 deraadt 479: }
1.125 deraadt 480:
1.2 provos 481: void
1.40 markus 482: packet_put_int(u_int value)
1.1 deraadt 483: {
1.14 markus 484: buffer_put_int(&outgoing_packet, value);
1.1 deraadt 485: }
1.125 deraadt 486:
1.2 provos 487: void
1.76 stevesk 488: packet_put_string(const void *buf, u_int len)
1.1 deraadt 489: {
1.14 markus 490: buffer_put_string(&outgoing_packet, buf, len);
1.1 deraadt 491: }
1.125 deraadt 492:
1.24 markus 493: void
494: packet_put_cstring(const char *str)
495: {
1.65 markus 496: buffer_put_cstring(&outgoing_packet, str);
1.24 markus 497: }
1.125 deraadt 498:
1.24 markus 499: void
1.76 stevesk 500: packet_put_raw(const void *buf, u_int len)
1.24 markus 501: {
502: buffer_append(&outgoing_packet, buf, len);
503: }
1.125 deraadt 504:
1.2 provos 505: void
1.14 markus 506: packet_put_bignum(BIGNUM * value)
1.1 deraadt 507: {
1.14 markus 508: buffer_put_bignum(&outgoing_packet, value);
1.1 deraadt 509: }
1.125 deraadt 510:
1.24 markus 511: void
512: packet_put_bignum2(BIGNUM * value)
513: {
514: buffer_put_bignum2(&outgoing_packet, value);
515: }
1.1 deraadt 516:
1.16 markus 517: /*
518: * Finalizes and sends the packet. If the encryption key has been set,
519: * encrypts the packet before sending.
520: */
1.14 markus 521:
1.68 itojun 522: static void
1.49 itojun 523: packet_send1(void)
1.1 deraadt 524: {
1.89 markus 525: u_char buf[8], *cp;
1.14 markus 526: int i, padding, len;
1.40 markus 527: u_int checksum;
1.115 avsm 528: u_int32_t rnd = 0;
1.14 markus 529:
1.16 markus 530: /*
531: * If using packet compression, compress the payload of the outgoing
532: * packet.
533: */
1.14 markus 534: if (packet_compression) {
535: buffer_clear(&compression_buffer);
536: /* Skip padding. */
537: buffer_consume(&outgoing_packet, 8);
538: /* padding */
539: buffer_append(&compression_buffer, "\0\0\0\0\0\0\0\0", 8);
540: buffer_compress(&outgoing_packet, &compression_buffer);
541: buffer_clear(&outgoing_packet);
542: buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer),
1.75 deraadt 543: buffer_len(&compression_buffer));
1.14 markus 544: }
545: /* Compute packet length without padding (add checksum, remove padding). */
546: len = buffer_len(&outgoing_packet) + 4 - 8;
547:
1.32 markus 548: /* Insert padding. Initialized to zero in packet_start1() */
1.14 markus 549: padding = 8 - len % 8;
1.88 markus 550: if (!send_context.plaintext) {
1.14 markus 551: cp = buffer_ptr(&outgoing_packet);
552: for (i = 0; i < padding; i++) {
553: if (i % 4 == 0)
1.115 avsm 554: rnd = arc4random();
555: cp[7 - i] = rnd & 0xff;
556: rnd >>= 8;
1.14 markus 557: }
558: }
559: buffer_consume(&outgoing_packet, 8 - padding);
560:
561: /* Add check bytes. */
1.83 stevesk 562: checksum = ssh_crc32(buffer_ptr(&outgoing_packet),
1.34 deraadt 563: buffer_len(&outgoing_packet));
1.131 djm 564: put_u32(buf, checksum);
1.14 markus 565: buffer_append(&outgoing_packet, buf, 4);
1.1 deraadt 566:
567: #ifdef PACKET_DEBUG
1.14 markus 568: fprintf(stderr, "packet_send plain: ");
569: buffer_dump(&outgoing_packet);
1.1 deraadt 570: #endif
571:
1.14 markus 572: /* Append to output. */
1.131 djm 573: put_u32(buf, len);
1.14 markus 574: buffer_append(&output, buf, 4);
1.76 stevesk 575: cp = buffer_append_space(&output, buffer_len(&outgoing_packet));
1.88 markus 576: cipher_crypt(&send_context, cp, buffer_ptr(&outgoing_packet),
1.75 deraadt 577: buffer_len(&outgoing_packet));
1.14 markus 578:
1.1 deraadt 579: #ifdef PACKET_DEBUG
1.14 markus 580: fprintf(stderr, "encrypted: ");
581: buffer_dump(&output);
1.1 deraadt 582: #endif
583:
1.14 markus 584: buffer_clear(&outgoing_packet);
1.1 deraadt 585:
1.16 markus 586: /*
1.120 djm 587: * Note that the packet is now only buffered in output. It won't be
1.16 markus 588: * actually sent until packet_write_wait or packet_write_poll is
589: * called.
590: */
1.1 deraadt 591: }
592:
1.91 markus 593: void
1.57 markus 594: set_newkeys(int mode)
595: {
596: Enc *enc;
597: Mac *mac;
598: Comp *comp;
599: CipherContext *cc;
1.105 markus 600: u_int64_t *max_blocks;
1.115 avsm 601: int crypt_type;
1.57 markus 602:
1.100 markus 603: debug2("set_newkeys: mode %d", mode);
1.57 markus 604:
1.88 markus 605: if (mode == MODE_OUT) {
606: cc = &send_context;
1.115 avsm 607: crypt_type = CIPHER_ENCRYPT;
1.105 markus 608: p_send.packets = p_send.blocks = 0;
609: max_blocks = &max_blocks_out;
1.88 markus 610: } else {
611: cc = &receive_context;
1.115 avsm 612: crypt_type = CIPHER_DECRYPT;
1.105 markus 613: p_read.packets = p_read.blocks = 0;
614: max_blocks = &max_blocks_in;
1.88 markus 615: }
1.57 markus 616: if (newkeys[mode] != NULL) {
1.100 markus 617: debug("set_newkeys: rekeying");
1.88 markus 618: cipher_cleanup(cc);
1.59 markus 619: enc = &newkeys[mode]->enc;
620: mac = &newkeys[mode]->mac;
621: comp = &newkeys[mode]->comp;
1.61 markus 622: memset(mac->key, 0, mac->key_len);
1.59 markus 623: xfree(enc->name);
624: xfree(enc->iv);
625: xfree(enc->key);
626: xfree(mac->name);
627: xfree(mac->key);
628: xfree(comp->name);
1.58 markus 629: xfree(newkeys[mode]);
1.57 markus 630: }
631: newkeys[mode] = kex_get_newkeys(mode);
632: if (newkeys[mode] == NULL)
633: fatal("newkeys: no keys for mode %d", mode);
634: enc = &newkeys[mode]->enc;
635: mac = &newkeys[mode]->mac;
636: comp = &newkeys[mode]->comp;
637: if (mac->md != NULL)
638: mac->enabled = 1;
639: DBG(debug("cipher_init_context: %d", mode));
1.88 markus 640: cipher_init(cc, enc->cipher, enc->key, enc->key_len,
1.115 avsm 641: enc->iv, enc->block_size, crypt_type);
1.91 markus 642: /* Deleting the keys does not gain extra security */
643: /* memset(enc->iv, 0, enc->block_size);
644: memset(enc->key, 0, enc->key_len); */
1.118 markus 645: if ((comp->type == COMP_ZLIB ||
646: (comp->type == COMP_DELAYED && after_authentication)) &&
647: comp->enabled == 0) {
1.60 markus 648: packet_init_compression();
649: if (mode == MODE_OUT)
650: buffer_compress_init_send(6);
651: else
652: buffer_compress_init_recv();
1.57 markus 653: comp->enabled = 1;
654: }
1.109 markus 655: /*
656: * The 2^(blocksize*2) limit is too expensive for 3DES,
657: * blowfish, etc, so enforce a 1GB limit for small blocksizes.
658: */
659: if (enc->block_size >= 16)
660: *max_blocks = (u_int64_t)1 << (enc->block_size*2);
661: else
662: *max_blocks = ((u_int64_t)1 << 30) / enc->block_size;
1.105 markus 663: if (rekey_limit)
664: *max_blocks = MIN(*max_blocks, rekey_limit / enc->block_size);
1.57 markus 665: }
666:
1.16 markus 667: /*
1.118 markus 668: * Delayed compression for SSH2 is enabled after authentication:
669: * This happans on the server side after a SSH2_MSG_USERAUTH_SUCCESS is sent,
670: * and on the client side after a SSH2_MSG_USERAUTH_SUCCESS is received.
671: */
672: static void
673: packet_enable_delayed_compress(void)
674: {
675: Comp *comp = NULL;
676: int mode;
677:
678: /*
679: * Remember that we are past the authentication step, so rekeying
680: * with COMP_DELAYED will turn on compression immediately.
681: */
682: after_authentication = 1;
683: for (mode = 0; mode < MODE_MAX; mode++) {
684: comp = &newkeys[mode]->comp;
685: if (comp && !comp->enabled && comp->type == COMP_DELAYED) {
1.119 markus 686: packet_init_compression();
1.118 markus 687: if (mode == MODE_OUT)
688: buffer_compress_init_send(6);
689: else
690: buffer_compress_init_recv();
691: comp->enabled = 1;
692: }
693: }
694: }
695:
696: /*
1.25 markus 697: * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue)
698: */
1.68 itojun 699: static void
1.105 markus 700: packet_send2_wrapped(void)
1.25 markus 701: {
1.89 markus 702: u_char type, *cp, *macbuf = NULL;
1.71 markus 703: u_char padlen, pad;
1.40 markus 704: u_int packet_length = 0;
1.71 markus 705: u_int i, len;
1.115 avsm 706: u_int32_t rnd = 0;
1.25 markus 707: Enc *enc = NULL;
708: Mac *mac = NULL;
709: Comp *comp = NULL;
710: int block_size;
711:
1.57 markus 712: if (newkeys[MODE_OUT] != NULL) {
713: enc = &newkeys[MODE_OUT]->enc;
714: mac = &newkeys[MODE_OUT]->mac;
715: comp = &newkeys[MODE_OUT]->comp;
1.25 markus 716: }
1.88 markus 717: block_size = enc ? enc->block_size : 8;
1.25 markus 718:
1.89 markus 719: cp = buffer_ptr(&outgoing_packet);
720: type = cp[5];
1.25 markus 721:
722: #ifdef PACKET_DEBUG
723: fprintf(stderr, "plain: ");
724: buffer_dump(&outgoing_packet);
725: #endif
726:
727: if (comp && comp->enabled) {
728: len = buffer_len(&outgoing_packet);
729: /* skip header, compress only payload */
730: buffer_consume(&outgoing_packet, 5);
731: buffer_clear(&compression_buffer);
732: buffer_compress(&outgoing_packet, &compression_buffer);
733: buffer_clear(&outgoing_packet);
734: buffer_append(&outgoing_packet, "\0\0\0\0\0", 5);
735: buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer),
736: buffer_len(&compression_buffer));
737: DBG(debug("compression: raw %d compressed %d", len,
738: buffer_len(&outgoing_packet)));
739: }
740:
741: /* sizeof (packet_len + pad_len + payload) */
742: len = buffer_len(&outgoing_packet);
743:
744: /*
745: * calc size of padding, alloc space, get random data,
746: * minimum padding is 4 bytes
747: */
748: padlen = block_size - (len % block_size);
749: if (padlen < 4)
750: padlen += block_size;
1.71 markus 751: if (extra_pad) {
752: /* will wrap if extra_pad+padlen > 255 */
753: extra_pad = roundup(extra_pad, block_size);
754: pad = extra_pad - ((len + padlen) % extra_pad);
1.93 markus 755: debug3("packet_send2: adding %d (len %d padlen %d extra_pad %d)",
1.71 markus 756: pad, len, padlen, extra_pad);
757: padlen += pad;
758: extra_pad = 0;
759: }
1.76 stevesk 760: cp = buffer_append_space(&outgoing_packet, padlen);
1.88 markus 761: if (enc && !send_context.plaintext) {
1.32 markus 762: /* random padding */
1.25 markus 763: for (i = 0; i < padlen; i++) {
764: if (i % 4 == 0)
1.115 avsm 765: rnd = arc4random();
766: cp[i] = rnd & 0xff;
767: rnd >>= 8;
1.25 markus 768: }
1.32 markus 769: } else {
770: /* clear padding */
771: memset(cp, 0, padlen);
1.25 markus 772: }
773: /* packet_length includes payload, padding and padding length field */
774: packet_length = buffer_len(&outgoing_packet) - 4;
1.89 markus 775: cp = buffer_ptr(&outgoing_packet);
1.131 djm 776: put_u32(cp, packet_length);
1.89 markus 777: cp[4] = padlen;
1.25 markus 778: DBG(debug("send: len %d (includes padlen %d)", packet_length+4, padlen));
779:
780: /* compute MAC over seqnr and packet(length fields, payload, padding) */
781: if (mac && mac->enabled) {
1.105 markus 782: macbuf = mac_compute(mac, p_send.seqnr,
1.83 stevesk 783: buffer_ptr(&outgoing_packet),
1.50 markus 784: buffer_len(&outgoing_packet));
1.105 markus 785: DBG(debug("done calc MAC out #%d", p_send.seqnr));
1.25 markus 786: }
787: /* encrypt packet and append to output buffer. */
1.76 stevesk 788: cp = buffer_append_space(&output, buffer_len(&outgoing_packet));
1.88 markus 789: cipher_crypt(&send_context, cp, buffer_ptr(&outgoing_packet),
1.25 markus 790: buffer_len(&outgoing_packet));
791: /* append unencrypted MAC */
792: if (mac && mac->enabled)
1.130 deraadt 793: buffer_append(&output, macbuf, mac->mac_len);
1.25 markus 794: #ifdef PACKET_DEBUG
795: fprintf(stderr, "encrypted: ");
796: buffer_dump(&output);
797: #endif
1.29 markus 798: /* increment sequence number for outgoing packets */
1.105 markus 799: if (++p_send.seqnr == 0)
1.106 itojun 800: logit("outgoing seqnr wraps around");
1.105 markus 801: if (++p_send.packets == 0)
802: if (!(datafellows & SSH_BUG_NOREKEY))
803: fatal("XXX too many packets with same key");
804: p_send.blocks += (packet_length + 4) / block_size;
1.25 markus 805: buffer_clear(&outgoing_packet);
806:
1.57 markus 807: if (type == SSH2_MSG_NEWKEYS)
808: set_newkeys(MODE_OUT);
1.118 markus 809: else if (type == SSH2_MSG_USERAUTH_SUCCESS && server_side)
810: packet_enable_delayed_compress();
1.25 markus 811: }
812:
1.105 markus 813: static void
814: packet_send2(void)
815: {
816: static int rekeying = 0;
817: struct packet *p;
818: u_char type, *cp;
819:
820: cp = buffer_ptr(&outgoing_packet);
821: type = cp[5];
822:
823: /* during rekeying we can only send key exchange messages */
824: if (rekeying) {
825: if (!((type >= SSH2_MSG_TRANSPORT_MIN) &&
826: (type <= SSH2_MSG_TRANSPORT_MAX))) {
827: debug("enqueue packet: %u", type);
828: p = xmalloc(sizeof(*p));
829: p->type = type;
830: memcpy(&p->payload, &outgoing_packet, sizeof(Buffer));
831: buffer_init(&outgoing_packet);
832: TAILQ_INSERT_TAIL(&outgoing, p, next);
833: return;
834: }
835: }
836:
837: /* rekeying starts with sending KEXINIT */
838: if (type == SSH2_MSG_KEXINIT)
839: rekeying = 1;
840:
841: packet_send2_wrapped();
842:
843: /* after a NEWKEYS message we can send the complete queue */
844: if (type == SSH2_MSG_NEWKEYS) {
845: rekeying = 0;
846: while ((p = TAILQ_FIRST(&outgoing))) {
847: type = p->type;
848: debug("dequeue packet: %u", type);
849: buffer_free(&outgoing_packet);
850: memcpy(&outgoing_packet, &p->payload,
851: sizeof(Buffer));
852: TAILQ_REMOVE(&outgoing, p, next);
853: xfree(p);
854: packet_send2_wrapped();
855: }
856: }
857: }
858:
1.25 markus 859: void
1.73 itojun 860: packet_send(void)
1.25 markus 861: {
1.62 markus 862: if (compat20)
1.25 markus 863: packet_send2();
864: else
865: packet_send1();
866: DBG(debug("packet_send done"));
867: }
868:
869: /*
1.16 markus 870: * Waits until a packet has been received, and returns its type. Note that
871: * no other data is processed until this returns, so this function should not
872: * be used during the interactive session.
873: */
1.1 deraadt 874:
1.2 provos 875: int
1.82 markus 876: packet_read_seqnr(u_int32_t *seqnr_p)
1.1 deraadt 877: {
1.14 markus 878: int type, len;
1.56 millert 879: fd_set *setp;
1.14 markus 880: char buf[8192];
1.25 markus 881: DBG(debug("packet_read()"));
1.14 markus 882:
1.127 djm 883: setp = (fd_set *)xcalloc(howmany(connection_in+1, NFDBITS),
1.56 millert 884: sizeof(fd_mask));
885:
1.14 markus 886: /* Since we are blocking, ensure that all written packets have been sent. */
887: packet_write_wait();
888:
889: /* Stay in the loop until we have received a complete packet. */
890: for (;;) {
891: /* Try to read a packet from the buffer. */
1.82 markus 892: type = packet_read_poll_seqnr(seqnr_p);
1.62 markus 893: if (!compat20 && (
1.32 markus 894: type == SSH_SMSG_SUCCESS
1.14 markus 895: || type == SSH_SMSG_FAILURE
896: || type == SSH_CMSG_EOF
1.32 markus 897: || type == SSH_CMSG_EXIT_CONFIRMATION))
1.79 markus 898: packet_check_eom();
1.14 markus 899: /* If we got a packet, return it. */
1.56 millert 900: if (type != SSH_MSG_NONE) {
901: xfree(setp);
1.14 markus 902: return type;
1.56 millert 903: }
1.16 markus 904: /*
905: * Otherwise, wait for some data to arrive, add it to the
906: * buffer, and try again.
907: */
1.56 millert 908: memset(setp, 0, howmany(connection_in + 1, NFDBITS) *
909: sizeof(fd_mask));
910: FD_SET(connection_in, setp);
1.16 markus 911:
1.14 markus 912: /* Wait for some data to arrive. */
1.56 millert 913: while (select(connection_in + 1, setp, NULL, NULL, NULL) == -1 &&
1.51 deraadt 914: (errno == EAGAIN || errno == EINTR))
915: ;
1.16 markus 916:
1.14 markus 917: /* Read data from the socket. */
918: len = read(connection_in, buf, sizeof(buf));
1.18 markus 919: if (len == 0) {
1.106 itojun 920: logit("Connection closed by %.200s", get_remote_ipaddr());
1.112 markus 921: cleanup_exit(255);
1.18 markus 922: }
1.14 markus 923: if (len < 0)
924: fatal("Read from socket failed: %.100s", strerror(errno));
925: /* Append it to the buffer. */
926: packet_process_incoming(buf, len);
927: }
928: /* NOTREACHED */
1.1 deraadt 929: }
930:
1.77 djm 931: int
1.82 markus 932: packet_read(void)
1.77 djm 933: {
1.82 markus 934: return packet_read_seqnr(NULL);
1.77 djm 935: }
936:
1.16 markus 937: /*
938: * Waits until a packet has been received, verifies that its type matches
939: * that given, and gives a fatal error and exits if there is a mismatch.
940: */
1.1 deraadt 941:
1.2 provos 942: void
1.82 markus 943: packet_read_expect(int expected_type)
1.1 deraadt 944: {
1.14 markus 945: int type;
1.1 deraadt 946:
1.82 markus 947: type = packet_read();
1.14 markus 948: if (type != expected_type)
949: packet_disconnect("Protocol error: expected packet type %d, got %d",
1.25 markus 950: expected_type, type);
1.1 deraadt 951: }
952:
953: /* Checks if a full packet is available in the data received so far via
1.14 markus 954: * packet_process_incoming. If so, reads the packet; otherwise returns
955: * SSH_MSG_NONE. This does not wait for data from the connection.
956: *
957: * SSH_MSG_DISCONNECT is handled specially here. Also,
958: * SSH_MSG_IGNORE messages are skipped by this function and are never returned
959: * to higher levels.
960: */
1.1 deraadt 961:
1.68 itojun 962: static int
1.82 markus 963: packet_read_poll1(void)
1.1 deraadt 964: {
1.40 markus 965: u_int len, padded_len;
1.89 markus 966: u_char *cp, type;
1.40 markus 967: u_int checksum, stored_checksum;
1.14 markus 968:
969: /* Check if input size is less than minimum packet size. */
970: if (buffer_len(&input) < 4 + 8)
971: return SSH_MSG_NONE;
972: /* Get length of incoming packet. */
1.89 markus 973: cp = buffer_ptr(&input);
1.131 djm 974: len = get_u32(cp);
1.14 markus 975: if (len < 1 + 2 + 2 || len > 256 * 1024)
1.98 markus 976: packet_disconnect("Bad packet length %u.", len);
1.14 markus 977: padded_len = (len + 8) & ~7;
978:
979: /* Check if the packet has been entirely received. */
980: if (buffer_len(&input) < 4 + padded_len)
981: return SSH_MSG_NONE;
982:
983: /* The entire packet is in buffer. */
984:
985: /* Consume packet length. */
986: buffer_consume(&input, 4);
987:
1.62 markus 988: /*
989: * Cryptographic attack detector for ssh
990: * (C)1998 CORE-SDI, Buenos Aires Argentina
991: * Ariel Futoransky(futo@core-sdi.com)
992: */
1.88 markus 993: if (!receive_context.plaintext &&
1.126 djm 994: detect_attack(buffer_ptr(&input), padded_len) == DEATTACK_DETECTED)
1.62 markus 995: packet_disconnect("crc32 compensation attack: network attack detected");
996:
997: /* Decrypt data to incoming_packet. */
1.14 markus 998: buffer_clear(&incoming_packet);
1.76 stevesk 999: cp = buffer_append_space(&incoming_packet, padded_len);
1.88 markus 1000: cipher_crypt(&receive_context, cp, buffer_ptr(&input), padded_len);
1.62 markus 1001:
1.14 markus 1002: buffer_consume(&input, padded_len);
1.1 deraadt 1003:
1004: #ifdef PACKET_DEBUG
1.14 markus 1005: fprintf(stderr, "read_poll plain: ");
1006: buffer_dump(&incoming_packet);
1.1 deraadt 1007: #endif
1008:
1.14 markus 1009: /* Compute packet checksum. */
1.83 stevesk 1010: checksum = ssh_crc32(buffer_ptr(&incoming_packet),
1.25 markus 1011: buffer_len(&incoming_packet) - 4);
1.14 markus 1012:
1013: /* Skip padding. */
1014: buffer_consume(&incoming_packet, 8 - len % 8);
1015:
1016: /* Test check bytes. */
1017: if (len != buffer_len(&incoming_packet))
1.77 djm 1018: packet_disconnect("packet_read_poll1: len %d != buffer_len %d.",
1.25 markus 1019: len, buffer_len(&incoming_packet));
1.14 markus 1020:
1.89 markus 1021: cp = (u_char *)buffer_ptr(&incoming_packet) + len - 4;
1.131 djm 1022: stored_checksum = get_u32(cp);
1.14 markus 1023: if (checksum != stored_checksum)
1024: packet_disconnect("Corrupted check bytes on input.");
1025: buffer_consume_end(&incoming_packet, 4);
1026:
1027: if (packet_compression) {
1028: buffer_clear(&compression_buffer);
1029: buffer_uncompress(&incoming_packet, &compression_buffer);
1030: buffer_clear(&incoming_packet);
1031: buffer_append(&incoming_packet, buffer_ptr(&compression_buffer),
1.25 markus 1032: buffer_len(&compression_buffer));
1.14 markus 1033: }
1.62 markus 1034: type = buffer_get_char(&incoming_packet);
1.116 markus 1035: if (type < SSH_MSG_MIN || type > SSH_MSG_MAX)
1036: packet_disconnect("Invalid ssh1 packet type: %d", type);
1.62 markus 1037: return type;
1.1 deraadt 1038: }
1.14 markus 1039:
1.68 itojun 1040: static int
1.82 markus 1041: packet_read_poll2(u_int32_t *seqnr_p)
1.25 markus 1042: {
1.50 markus 1043: static u_int packet_length = 0;
1.40 markus 1044: u_int padlen, need;
1.89 markus 1045: u_char *macbuf, *cp, type;
1.117 djm 1046: u_int maclen, block_size;
1.25 markus 1047: Enc *enc = NULL;
1048: Mac *mac = NULL;
1049: Comp *comp = NULL;
1050:
1.57 markus 1051: if (newkeys[MODE_IN] != NULL) {
1052: enc = &newkeys[MODE_IN]->enc;
1053: mac = &newkeys[MODE_IN]->mac;
1054: comp = &newkeys[MODE_IN]->comp;
1.25 markus 1055: }
1056: maclen = mac && mac->enabled ? mac->mac_len : 0;
1.88 markus 1057: block_size = enc ? enc->block_size : 8;
1.25 markus 1058:
1059: if (packet_length == 0) {
1060: /*
1061: * check if input size is less than the cipher block size,
1062: * decrypt first block and extract length of incoming packet
1063: */
1064: if (buffer_len(&input) < block_size)
1065: return SSH_MSG_NONE;
1066: buffer_clear(&incoming_packet);
1.76 stevesk 1067: cp = buffer_append_space(&incoming_packet, block_size);
1.88 markus 1068: cipher_crypt(&receive_context, cp, buffer_ptr(&input),
1.25 markus 1069: block_size);
1.89 markus 1070: cp = buffer_ptr(&incoming_packet);
1.131 djm 1071: packet_length = get_u32(cp);
1.25 markus 1072: if (packet_length < 1 + 4 || packet_length > 256 * 1024) {
1.110 markus 1073: #ifdef PACKET_DEBUG
1.25 markus 1074: buffer_dump(&incoming_packet);
1.110 markus 1075: #endif
1.98 markus 1076: packet_disconnect("Bad packet length %u.", packet_length);
1.25 markus 1077: }
1.98 markus 1078: DBG(debug("input: packet len %u", packet_length+4));
1.25 markus 1079: buffer_consume(&input, block_size);
1080: }
1081: /* we have a partial packet of block_size bytes */
1082: need = 4 + packet_length - block_size;
1083: DBG(debug("partial packet %d, need %d, maclen %d", block_size,
1084: need, maclen));
1085: if (need % block_size != 0)
1086: fatal("padding error: need %d block %d mod %d",
1087: need, block_size, need % block_size);
1088: /*
1089: * check if the entire packet has been received and
1090: * decrypt into incoming_packet
1091: */
1092: if (buffer_len(&input) < need + maclen)
1093: return SSH_MSG_NONE;
1094: #ifdef PACKET_DEBUG
1095: fprintf(stderr, "read_poll enc/full: ");
1096: buffer_dump(&input);
1097: #endif
1.76 stevesk 1098: cp = buffer_append_space(&incoming_packet, need);
1.88 markus 1099: cipher_crypt(&receive_context, cp, buffer_ptr(&input), need);
1.25 markus 1100: buffer_consume(&input, need);
1101: /*
1102: * compute MAC over seqnr and packet,
1103: * increment sequence number for incoming packet
1104: */
1.29 markus 1105: if (mac && mac->enabled) {
1.105 markus 1106: macbuf = mac_compute(mac, p_read.seqnr,
1.83 stevesk 1107: buffer_ptr(&incoming_packet),
1.50 markus 1108: buffer_len(&incoming_packet));
1.25 markus 1109: if (memcmp(macbuf, buffer_ptr(&input), mac->mac_len) != 0)
1.36 markus 1110: packet_disconnect("Corrupted MAC on input.");
1.105 markus 1111: DBG(debug("MAC #%d ok", p_read.seqnr));
1.25 markus 1112: buffer_consume(&input, mac->mac_len);
1113: }
1.77 djm 1114: if (seqnr_p != NULL)
1.105 markus 1115: *seqnr_p = p_read.seqnr;
1116: if (++p_read.seqnr == 0)
1.106 itojun 1117: logit("incoming seqnr wraps around");
1.105 markus 1118: if (++p_read.packets == 0)
1119: if (!(datafellows & SSH_BUG_NOREKEY))
1120: fatal("XXX too many packets with same key");
1121: p_read.blocks += (packet_length + 4) / block_size;
1.25 markus 1122:
1123: /* get padlen */
1.76 stevesk 1124: cp = buffer_ptr(&incoming_packet);
1.89 markus 1125: padlen = cp[4];
1.25 markus 1126: DBG(debug("input: padlen %d", padlen));
1127: if (padlen < 4)
1128: packet_disconnect("Corrupted padlen %d on input.", padlen);
1129:
1130: /* skip packet size + padlen, discard padding */
1131: buffer_consume(&incoming_packet, 4 + 1);
1132: buffer_consume_end(&incoming_packet, padlen);
1133:
1134: DBG(debug("input: len before de-compress %d", buffer_len(&incoming_packet)));
1135: if (comp && comp->enabled) {
1136: buffer_clear(&compression_buffer);
1137: buffer_uncompress(&incoming_packet, &compression_buffer);
1138: buffer_clear(&incoming_packet);
1139: buffer_append(&incoming_packet, buffer_ptr(&compression_buffer),
1140: buffer_len(&compression_buffer));
1.97 deraadt 1141: DBG(debug("input: len after de-compress %d",
1142: buffer_len(&incoming_packet)));
1.25 markus 1143: }
1144: /*
1145: * get packet type, implies consume.
1146: * return length of payload (without type field)
1147: */
1.62 markus 1148: type = buffer_get_char(&incoming_packet);
1.116 markus 1149: if (type < SSH2_MSG_MIN || type >= SSH2_MSG_LOCAL_MIN)
1150: packet_disconnect("Invalid ssh2 packet type: %d", type);
1.57 markus 1151: if (type == SSH2_MSG_NEWKEYS)
1152: set_newkeys(MODE_IN);
1.118 markus 1153: else if (type == SSH2_MSG_USERAUTH_SUCCESS && !server_side)
1154: packet_enable_delayed_compress();
1.25 markus 1155: #ifdef PACKET_DEBUG
1.55 deraadt 1156: fprintf(stderr, "read/plain[%d]:\r\n", type);
1.25 markus 1157: buffer_dump(&incoming_packet);
1158: #endif
1.62 markus 1159: /* reset for next packet */
1160: packet_length = 0;
1161: return type;
1.25 markus 1162: }
1163:
1164: int
1.82 markus 1165: packet_read_poll_seqnr(u_int32_t *seqnr_p)
1.25 markus 1166: {
1.96 deraadt 1167: u_int reason, seqnr;
1.62 markus 1168: u_char type;
1.25 markus 1169: char *msg;
1.62 markus 1170:
1.25 markus 1171: for (;;) {
1.62 markus 1172: if (compat20) {
1.82 markus 1173: type = packet_read_poll2(seqnr_p);
1.62 markus 1174: if (type)
1.25 markus 1175: DBG(debug("received packet type %d", type));
1.74 deraadt 1176: switch (type) {
1.25 markus 1177: case SSH2_MSG_IGNORE:
1178: break;
1179: case SSH2_MSG_DEBUG:
1180: packet_get_char();
1181: msg = packet_get_string(NULL);
1182: debug("Remote: %.900s", msg);
1183: xfree(msg);
1184: msg = packet_get_string(NULL);
1185: xfree(msg);
1186: break;
1187: case SSH2_MSG_DISCONNECT:
1188: reason = packet_get_int();
1189: msg = packet_get_string(NULL);
1.106 itojun 1190: logit("Received disconnect from %s: %u: %.400s",
1.96 deraadt 1191: get_remote_ipaddr(), reason, msg);
1.25 markus 1192: xfree(msg);
1.112 markus 1193: cleanup_exit(255);
1.84 markus 1194: break;
1195: case SSH2_MSG_UNIMPLEMENTED:
1196: seqnr = packet_get_int();
1.96 deraadt 1197: debug("Received SSH2_MSG_UNIMPLEMENTED for %u",
1198: seqnr);
1.25 markus 1199: break;
1200: default:
1201: return type;
1.48 stevesk 1202: }
1.25 markus 1203: } else {
1.82 markus 1204: type = packet_read_poll1();
1.74 deraadt 1205: switch (type) {
1.25 markus 1206: case SSH_MSG_IGNORE:
1207: break;
1208: case SSH_MSG_DEBUG:
1209: msg = packet_get_string(NULL);
1210: debug("Remote: %.900s", msg);
1211: xfree(msg);
1212: break;
1213: case SSH_MSG_DISCONNECT:
1214: msg = packet_get_string(NULL);
1.106 itojun 1215: logit("Received disconnect from %s: %.400s",
1.96 deraadt 1216: get_remote_ipaddr(), msg);
1.112 markus 1217: cleanup_exit(255);
1.25 markus 1218: xfree(msg);
1219: break;
1220: default:
1.62 markus 1221: if (type)
1.25 markus 1222: DBG(debug("received packet type %d", type));
1223: return type;
1.48 stevesk 1224: }
1.25 markus 1225: }
1226: }
1.77 djm 1227: }
1228:
1229: int
1.82 markus 1230: packet_read_poll(void)
1.77 djm 1231: {
1.82 markus 1232: return packet_read_poll_seqnr(NULL);
1.25 markus 1233: }
1234:
1.16 markus 1235: /*
1236: * Buffers the given amount of input characters. This is intended to be used
1237: * together with packet_read_poll.
1238: */
1.1 deraadt 1239:
1.2 provos 1240: void
1.40 markus 1241: packet_process_incoming(const char *buf, u_int len)
1.1 deraadt 1242: {
1.14 markus 1243: buffer_append(&input, buf, len);
1.1 deraadt 1244: }
1245:
1246: /* Returns a character from the packet. */
1247:
1.40 markus 1248: u_int
1.73 itojun 1249: packet_get_char(void)
1.1 deraadt 1250: {
1.14 markus 1251: char ch;
1.97 deraadt 1252:
1.14 markus 1253: buffer_get(&incoming_packet, &ch, 1);
1.40 markus 1254: return (u_char) ch;
1.1 deraadt 1255: }
1256:
1257: /* Returns an integer from the packet data. */
1258:
1.40 markus 1259: u_int
1.73 itojun 1260: packet_get_int(void)
1.1 deraadt 1261: {
1.14 markus 1262: return buffer_get_int(&incoming_packet);
1.1 deraadt 1263: }
1264:
1.16 markus 1265: /*
1266: * Returns an arbitrary precision integer from the packet data. The integer
1267: * must have been initialized before this call.
1268: */
1.1 deraadt 1269:
1.2 provos 1270: void
1.80 markus 1271: packet_get_bignum(BIGNUM * value)
1.1 deraadt 1272: {
1.81 markus 1273: buffer_get_bignum(&incoming_packet, value);
1.24 markus 1274: }
1275:
1276: void
1.80 markus 1277: packet_get_bignum2(BIGNUM * value)
1.24 markus 1278: {
1.81 markus 1279: buffer_get_bignum2(&incoming_packet, value);
1.24 markus 1280: }
1281:
1.76 stevesk 1282: void *
1.117 djm 1283: packet_get_raw(u_int *length_ptr)
1.24 markus 1284: {
1.117 djm 1285: u_int bytes = buffer_len(&incoming_packet);
1.97 deraadt 1286:
1.24 markus 1287: if (length_ptr != NULL)
1288: *length_ptr = bytes;
1289: return buffer_ptr(&incoming_packet);
1.28 markus 1290: }
1291:
1292: int
1293: packet_remaining(void)
1294: {
1295: return buffer_len(&incoming_packet);
1.1 deraadt 1296: }
1297:
1.16 markus 1298: /*
1299: * Returns a string from the packet data. The string is allocated using
1300: * xmalloc; it is the responsibility of the calling program to free it when
1301: * no longer needed. The length_ptr argument may be NULL, or point to an
1302: * integer into which the length of the string is stored.
1303: */
1.1 deraadt 1304:
1.76 stevesk 1305: void *
1.40 markus 1306: packet_get_string(u_int *length_ptr)
1.1 deraadt 1307: {
1.14 markus 1308: return buffer_get_string(&incoming_packet, length_ptr);
1.1 deraadt 1309: }
1310:
1.16 markus 1311: /*
1312: * Sends a diagnostic message from the server to the client. This message
1313: * can be sent at any time (but not while constructing another message). The
1314: * message is printed immediately, but only if the client is being executed
1315: * in verbose mode. These messages are primarily intended to ease debugging
1316: * authentication problems. The length of the formatted message must not
1317: * exceed 1024 bytes. This will automatically call packet_write_wait.
1318: */
1.1 deraadt 1319:
1.2 provos 1320: void
1.14 markus 1321: packet_send_debug(const char *fmt,...)
1.1 deraadt 1322: {
1.14 markus 1323: char buf[1024];
1324: va_list args;
1.39 markus 1325:
1326: if (compat20 && (datafellows & SSH_BUG_DEBUG))
1327: return;
1.14 markus 1328:
1329: va_start(args, fmt);
1330: vsnprintf(buf, sizeof(buf), fmt, args);
1331: va_end(args);
1332:
1.30 markus 1333: if (compat20) {
1334: packet_start(SSH2_MSG_DEBUG);
1335: packet_put_char(0); /* bool: always display */
1336: packet_put_cstring(buf);
1337: packet_put_cstring("");
1338: } else {
1339: packet_start(SSH_MSG_DEBUG);
1340: packet_put_cstring(buf);
1341: }
1.14 markus 1342: packet_send();
1343: packet_write_wait();
1.1 deraadt 1344: }
1345:
1.16 markus 1346: /*
1347: * Logs the error plus constructs and sends a disconnect packet, closes the
1348: * connection, and exits. This function never returns. The error message
1349: * should not contain a newline. The length of the formatted message must
1350: * not exceed 1024 bytes.
1351: */
1.1 deraadt 1352:
1.2 provos 1353: void
1.14 markus 1354: packet_disconnect(const char *fmt,...)
1.1 deraadt 1355: {
1.14 markus 1356: char buf[1024];
1357: va_list args;
1358: static int disconnecting = 0;
1.97 deraadt 1359:
1.14 markus 1360: if (disconnecting) /* Guard against recursive invocations. */
1361: fatal("packet_disconnect called recursively.");
1362: disconnecting = 1;
1363:
1.16 markus 1364: /*
1365: * Format the message. Note that the caller must make sure the
1366: * message is of limited size.
1367: */
1.14 markus 1368: va_start(args, fmt);
1369: vsnprintf(buf, sizeof(buf), fmt, args);
1370: va_end(args);
1371:
1.99 markus 1372: /* Display the error locally */
1.106 itojun 1373: logit("Disconnecting: %.100s", buf);
1.99 markus 1374:
1.14 markus 1375: /* Send the disconnect message to the other side, and wait for it to get sent. */
1.25 markus 1376: if (compat20) {
1377: packet_start(SSH2_MSG_DISCONNECT);
1378: packet_put_int(SSH2_DISCONNECT_PROTOCOL_ERROR);
1379: packet_put_cstring(buf);
1380: packet_put_cstring("");
1381: } else {
1382: packet_start(SSH_MSG_DISCONNECT);
1.65 markus 1383: packet_put_cstring(buf);
1.25 markus 1384: }
1.14 markus 1385: packet_send();
1386: packet_write_wait();
1387:
1388: /* Stop listening for connections. */
1.67 markus 1389: channel_close_all();
1.14 markus 1390:
1391: /* Close the connection. */
1392: packet_close();
1.112 markus 1393: cleanup_exit(255);
1.1 deraadt 1394: }
1395:
1.16 markus 1396: /* Checks if there is any buffered output, and tries to write some of the output. */
1.1 deraadt 1397:
1.2 provos 1398: void
1.73 itojun 1399: packet_write_poll(void)
1.1 deraadt 1400: {
1.14 markus 1401: int len = buffer_len(&output);
1.97 deraadt 1402:
1.14 markus 1403: if (len > 0) {
1404: len = write(connection_out, buffer_ptr(&output), len);
1405: if (len <= 0) {
1406: if (errno == EAGAIN)
1407: return;
1408: else
1409: fatal("Write failed: %.100s", strerror(errno));
1410: }
1411: buffer_consume(&output, len);
1412: }
1.1 deraadt 1413: }
1414:
1.16 markus 1415: /*
1416: * Calls packet_write_poll repeatedly until all pending output data has been
1417: * written.
1418: */
1.1 deraadt 1419:
1.2 provos 1420: void
1.73 itojun 1421: packet_write_wait(void)
1.1 deraadt 1422: {
1.56 millert 1423: fd_set *setp;
1424:
1.127 djm 1425: setp = (fd_set *)xcalloc(howmany(connection_out + 1, NFDBITS),
1.56 millert 1426: sizeof(fd_mask));
1.14 markus 1427: packet_write_poll();
1428: while (packet_have_data_to_write()) {
1.56 millert 1429: memset(setp, 0, howmany(connection_out + 1, NFDBITS) *
1430: sizeof(fd_mask));
1431: FD_SET(connection_out, setp);
1432: while (select(connection_out + 1, NULL, setp, NULL, NULL) == -1 &&
1.51 deraadt 1433: (errno == EAGAIN || errno == EINTR))
1434: ;
1.14 markus 1435: packet_write_poll();
1436: }
1.56 millert 1437: xfree(setp);
1.1 deraadt 1438: }
1439:
1440: /* Returns true if there is buffered data to write to the connection. */
1441:
1.2 provos 1442: int
1.73 itojun 1443: packet_have_data_to_write(void)
1.1 deraadt 1444: {
1.14 markus 1445: return buffer_len(&output) != 0;
1.1 deraadt 1446: }
1447:
1448: /* Returns true if there is not too much data to write to the connection. */
1449:
1.2 provos 1450: int
1.73 itojun 1451: packet_not_very_much_data_to_write(void)
1.1 deraadt 1452: {
1.14 markus 1453: if (interactive_mode)
1454: return buffer_len(&output) < 16384;
1455: else
1456: return buffer_len(&output) < 128 * 1024;
1.1 deraadt 1457: }
1458:
1.102 markus 1459: static void
1.101 markus 1460: packet_set_tos(int interactive)
1461: {
1462: int tos = interactive ? IPTOS_LOWDELAY : IPTOS_THROUGHPUT;
1463:
1464: if (!packet_connection_is_on_socket() ||
1465: !packet_connection_is_ipv4())
1466: return;
1467: if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, &tos,
1468: sizeof(tos)) < 0)
1469: error("setsockopt IP_TOS %d: %.100s:",
1470: tos, strerror(errno));
1471: }
1472:
1.1 deraadt 1473: /* Informs that the current session is interactive. Sets IP flags for that. */
1474:
1.2 provos 1475: void
1.43 markus 1476: packet_set_interactive(int interactive)
1.1 deraadt 1477: {
1.43 markus 1478: static int called = 0;
1.44 markus 1479:
1.43 markus 1480: if (called)
1481: return;
1482: called = 1;
1.1 deraadt 1483:
1.14 markus 1484: /* Record that we are in interactive mode. */
1485: interactive_mode = interactive;
1.1 deraadt 1486:
1.19 markus 1487: /* Only set socket options if using a socket. */
1488: if (!packet_connection_is_on_socket())
1.14 markus 1489: return;
1.122 dtucker 1490: set_nodelay(connection_in);
1.101 markus 1491: packet_set_tos(interactive);
1.1 deraadt 1492: }
1493:
1494: /* Returns true if the current connection is interactive. */
1495:
1.2 provos 1496: int
1.73 itojun 1497: packet_is_interactive(void)
1.1 deraadt 1498: {
1.14 markus 1499: return interactive_mode;
1.12 markus 1500: }
1501:
1.113 deraadt 1502: int
1.108 markus 1503: packet_set_maxsize(u_int s)
1.12 markus 1504: {
1.14 markus 1505: static int called = 0;
1.97 deraadt 1506:
1.14 markus 1507: if (called) {
1.106 itojun 1508: logit("packet_set_maxsize: called twice: old %d new %d",
1.25 markus 1509: max_packet_size, s);
1.14 markus 1510: return -1;
1511: }
1512: if (s < 4 * 1024 || s > 1024 * 1024) {
1.106 itojun 1513: logit("packet_set_maxsize: bad size %d", s);
1.14 markus 1514: return -1;
1515: }
1.70 markus 1516: called = 1;
1.66 markus 1517: debug("packet_set_maxsize: setting to %d", s);
1.14 markus 1518: max_packet_size = s;
1519: return s;
1.53 markus 1520: }
1521:
1.71 markus 1522: /* roundup current message to pad bytes */
1523: void
1524: packet_add_padding(u_char pad)
1525: {
1526: extra_pad = pad;
1527: }
1528:
1.53 markus 1529: /*
1530: * 9.2. Ignored Data Message
1.61 markus 1531: *
1.53 markus 1532: * byte SSH_MSG_IGNORE
1533: * string data
1.61 markus 1534: *
1.53 markus 1535: * All implementations MUST understand (and ignore) this message at any
1536: * time (after receiving the protocol version). No implementation is
1537: * required to send them. This message can be used as an additional
1538: * protection measure against advanced traffic analysis techniques.
1539: */
1.54 markus 1540: void
1541: packet_send_ignore(int nbytes)
1542: {
1.115 avsm 1543: u_int32_t rnd = 0;
1.54 markus 1544: int i;
1545:
1546: packet_start(compat20 ? SSH2_MSG_IGNORE : SSH_MSG_IGNORE);
1.53 markus 1547: packet_put_int(nbytes);
1.75 deraadt 1548: for (i = 0; i < nbytes; i++) {
1.53 markus 1549: if (i % 4 == 0)
1.115 avsm 1550: rnd = arc4random();
1.129 deraadt 1551: packet_put_char((u_char)rnd & 0xff);
1.115 avsm 1552: rnd >>= 8;
1.53 markus 1553: }
1.105 markus 1554: }
1555:
1.113 deraadt 1556: #define MAX_PACKETS (1U<<31)
1.105 markus 1557: int
1558: packet_need_rekeying(void)
1559: {
1560: if (datafellows & SSH_BUG_NOREKEY)
1561: return 0;
1562: return
1563: (p_send.packets > MAX_PACKETS) ||
1564: (p_read.packets > MAX_PACKETS) ||
1565: (max_blocks_out && (p_send.blocks > max_blocks_out)) ||
1566: (max_blocks_in && (p_read.blocks > max_blocks_in));
1567: }
1568:
1569: void
1570: packet_set_rekey_limit(u_int32_t bytes)
1571: {
1572: rekey_limit = bytes;
1.118 markus 1573: }
1574:
1575: void
1576: packet_set_server(void)
1577: {
1578: server_side = 1;
1579: }
1580:
1581: void
1582: packet_set_authenticated(void)
1583: {
1584: after_authentication = 1;
1.1 deraadt 1585: }
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