Annotation of src/usr.bin/ssh/packet.c, Revision 1.105
1.1 deraadt 1: /*
1.15 deraadt 2: * Author: Tatu Ylonen <ylo@cs.hut.fi>
3: * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
4: * All rights reserved
1.35 deraadt 5: * This file contains code implementing the packet protocol and communication
6: * with the other side. This same code is used both on client and server side.
1.29 markus 7: *
1.35 deraadt 8: * As far as I am concerned, the code I have written for this software
9: * can be used freely for any purpose. Any derived versions of this
10: * software must be clearly marked as such, and if the derived work is
11: * incompatible with the protocol description in the RFC file, it must be
12: * called by a name other than "ssh" or "Secure Shell".
1.29 markus 13: *
1.25 markus 14: *
15: * SSH2 packet format added by Markus Friedl.
1.69 markus 16: * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
1.25 markus 17: *
1.35 deraadt 18: * Redistribution and use in source and binary forms, with or without
19: * modification, are permitted provided that the following conditions
20: * are met:
21: * 1. Redistributions of source code must retain the above copyright
22: * notice, this list of conditions and the following disclaimer.
23: * 2. Redistributions in binary form must reproduce the above copyright
24: * notice, this list of conditions and the following disclaimer in the
25: * documentation and/or other materials provided with the distribution.
26: *
27: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
28: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
29: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
30: * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
31: * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
32: * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
33: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
34: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
35: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
36: * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1.15 deraadt 37: */
1.1 deraadt 38:
39: #include "includes.h"
1.105 ! markus 40: RCSID("$OpenBSD: packet.c,v 1.104 2003/04/01 10:22:21 markus Exp $");
! 41:
! 42: #include <sys/queue.h>
1.1 deraadt 43:
44: #include "xmalloc.h"
45: #include "buffer.h"
46: #include "packet.h"
47: #include "bufaux.h"
48: #include "crc32.h"
49: #include "getput.h"
50:
51: #include "compress.h"
1.9 dugsong 52: #include "deattack.h"
1.64 markus 53: #include "channels.h"
1.1 deraadt 54:
1.25 markus 55: #include "compat.h"
1.45 markus 56: #include "ssh1.h"
1.25 markus 57: #include "ssh2.h"
58:
1.37 markus 59: #include "cipher.h"
1.25 markus 60: #include "kex.h"
1.50 markus 61: #include "mac.h"
1.46 markus 62: #include "log.h"
63: #include "canohost.h"
1.87 stevesk 64: #include "misc.h"
1.95 markus 65: #include "ssh.h"
1.25 markus 66:
67: #ifdef PACKET_DEBUG
68: #define DBG(x) x
69: #else
70: #define DBG(x)
71: #endif
72:
1.16 markus 73: /*
74: * This variable contains the file descriptors used for communicating with
75: * the other side. connection_in is used for reading; connection_out for
76: * writing. These can be the same descriptor, in which case it is assumed to
77: * be a socket.
78: */
1.1 deraadt 79: static int connection_in = -1;
80: static int connection_out = -1;
81:
82: /* Protocol flags for the remote side. */
1.40 markus 83: static u_int remote_protocol_flags = 0;
1.1 deraadt 84:
85: /* Encryption context for receiving data. This is only used for decryption. */
86: static CipherContext receive_context;
1.14 markus 87:
88: /* Encryption context for sending data. This is only used for encryption. */
1.1 deraadt 89: static CipherContext send_context;
90:
91: /* Buffer for raw input data from the socket. */
1.91 markus 92: Buffer input;
1.1 deraadt 93:
94: /* Buffer for raw output data going to the socket. */
1.91 markus 95: Buffer output;
1.1 deraadt 96:
97: /* Buffer for the partial outgoing packet being constructed. */
98: static Buffer outgoing_packet;
99:
100: /* Buffer for the incoming packet currently being processed. */
101: static Buffer incoming_packet;
102:
103: /* Scratch buffer for packet compression/decompression. */
104: static Buffer compression_buffer;
1.60 markus 105: static int compression_buffer_ready = 0;
1.1 deraadt 106:
107: /* Flag indicating whether packet compression/decompression is enabled. */
108: static int packet_compression = 0;
109:
1.12 markus 110: /* default maximum packet size */
111: int max_packet_size = 32768;
112:
1.1 deraadt 113: /* Flag indicating whether this module has been initialized. */
114: static int initialized = 0;
115:
116: /* Set to true if the connection is interactive. */
117: static int interactive_mode = 0;
118:
1.25 markus 119: /* Session key information for Encryption and MAC */
1.57 markus 120: Newkeys *newkeys[MODE_MAX];
1.105 ! markus 121: static struct packet_state {
! 122: u_int32_t seqnr;
! 123: u_int32_t packets;
! 124: u_int64_t blocks;
! 125: } p_read, p_send;
! 126:
! 127: static u_int64_t max_blocks_in, max_blocks_out;
! 128: static u_int32_t rekey_limit;
1.25 markus 129:
1.95 markus 130: /* Session key for protocol v1 */
131: static u_char ssh1_key[SSH_SESSION_KEY_LENGTH];
132: static u_int ssh1_keylen;
133:
1.71 markus 134: /* roundup current message to extra_pad bytes */
135: static u_char extra_pad = 0;
136:
1.105 ! markus 137: struct packet {
! 138: TAILQ_ENTRY(packet) next;
! 139: u_char type;
! 140: Buffer payload;
! 141: };
! 142: TAILQ_HEAD(, packet) outgoing;
! 143:
1.16 markus 144: /*
145: * Sets the descriptors used for communication. Disables encryption until
146: * packet_set_encryption_key is called.
147: */
1.2 provos 148: void
149: packet_set_connection(int fd_in, int fd_out)
1.1 deraadt 150: {
1.37 markus 151: Cipher *none = cipher_by_name("none");
1.97 deraadt 152:
1.37 markus 153: if (none == NULL)
154: fatal("packet_set_connection: cannot load cipher 'none'");
1.14 markus 155: connection_in = fd_in;
156: connection_out = fd_out;
1.88 markus 157: cipher_init(&send_context, none, "", 0, NULL, 0, CIPHER_ENCRYPT);
158: cipher_init(&receive_context, none, "", 0, NULL, 0, CIPHER_DECRYPT);
1.62 markus 159: newkeys[MODE_IN] = newkeys[MODE_OUT] = NULL;
1.14 markus 160: if (!initialized) {
161: initialized = 1;
162: buffer_init(&input);
163: buffer_init(&output);
164: buffer_init(&outgoing_packet);
165: buffer_init(&incoming_packet);
1.105 ! markus 166: TAILQ_INIT(&outgoing);
1.14 markus 167: }
168: /* Kludge: arrange the close function to be called from fatal(). */
169: fatal_add_cleanup((void (*) (void *)) packet_close, NULL);
1.1 deraadt 170: }
171:
1.19 markus 172: /* Returns 1 if remote host is connected via socket, 0 if not. */
173:
174: int
1.73 itojun 175: packet_connection_is_on_socket(void)
1.19 markus 176: {
177: struct sockaddr_storage from, to;
178: socklen_t fromlen, tolen;
179:
180: /* filedescriptors in and out are the same, so it's a socket */
181: if (connection_in == connection_out)
182: return 1;
183: fromlen = sizeof(from);
184: memset(&from, 0, sizeof(from));
1.20 markus 185: if (getpeername(connection_in, (struct sockaddr *)&from, &fromlen) < 0)
1.19 markus 186: return 0;
187: tolen = sizeof(to);
188: memset(&to, 0, sizeof(to));
1.20 markus 189: if (getpeername(connection_out, (struct sockaddr *)&to, &tolen) < 0)
1.19 markus 190: return 0;
191: if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0)
192: return 0;
193: if (from.ss_family != AF_INET && from.ss_family != AF_INET6)
194: return 0;
195: return 1;
196: }
197:
1.92 markus 198: /*
1.91 markus 199: * Exports an IV from the CipherContext required to export the key
200: * state back from the unprivileged child to the privileged parent
201: * process.
202: */
203:
204: void
205: packet_get_keyiv(int mode, u_char *iv, u_int len)
206: {
207: CipherContext *cc;
208:
209: if (mode == MODE_OUT)
210: cc = &send_context;
211: else
212: cc = &receive_context;
213:
214: cipher_get_keyiv(cc, iv, len);
215: }
216:
217: int
218: packet_get_keycontext(int mode, u_char *dat)
219: {
220: CipherContext *cc;
1.92 markus 221:
1.91 markus 222: if (mode == MODE_OUT)
223: cc = &send_context;
224: else
225: cc = &receive_context;
226:
227: return (cipher_get_keycontext(cc, dat));
228: }
229:
230: void
231: packet_set_keycontext(int mode, u_char *dat)
232: {
233: CipherContext *cc;
1.92 markus 234:
1.91 markus 235: if (mode == MODE_OUT)
236: cc = &send_context;
237: else
238: cc = &receive_context;
239:
240: cipher_set_keycontext(cc, dat);
241: }
242:
243: int
244: packet_get_keyiv_len(int mode)
245: {
246: CipherContext *cc;
247:
248: if (mode == MODE_OUT)
249: cc = &send_context;
250: else
251: cc = &receive_context;
252:
253: return (cipher_get_keyiv_len(cc));
254: }
255: void
256: packet_set_iv(int mode, u_char *dat)
257: {
258: CipherContext *cc;
259:
260: if (mode == MODE_OUT)
261: cc = &send_context;
262: else
263: cc = &receive_context;
264:
265: cipher_set_keyiv(cc, dat);
266: }
267: int
268: packet_get_ssh1_cipher()
269: {
270: return (cipher_get_number(receive_context.cipher));
271: }
272:
1.105 ! markus 273: void
! 274: packet_get_state(int mode, u_int32_t *seqnr, u_int64_t *blocks, u_int32_t *packets)
! 275: {
! 276: struct packet_state *state;
1.104 markus 277:
1.105 ! markus 278: state = (mode == MODE_IN) ? &p_read : &p_send;
! 279: *seqnr = state->seqnr;
! 280: *blocks = state->blocks;
! 281: *packets = state->packets;
1.91 markus 282: }
283:
284: void
1.105 ! markus 285: packet_set_state(int mode, u_int32_t seqnr, u_int64_t blocks, u_int32_t packets)
1.91 markus 286: {
1.105 ! markus 287: struct packet_state *state;
! 288:
! 289: state = (mode == MODE_IN) ? &p_read : &p_send;
! 290: state->seqnr = seqnr;
! 291: state->blocks = blocks;
! 292: state->packets = packets;
1.91 markus 293: }
294:
1.19 markus 295: /* returns 1 if connection is via ipv4 */
296:
297: int
1.73 itojun 298: packet_connection_is_ipv4(void)
1.19 markus 299: {
300: struct sockaddr_storage to;
1.21 deraadt 301: socklen_t tolen = sizeof(to);
1.19 markus 302:
303: memset(&to, 0, sizeof(to));
304: if (getsockname(connection_out, (struct sockaddr *)&to, &tolen) < 0)
305: return 0;
306: if (to.ss_family != AF_INET)
307: return 0;
308: return 1;
309: }
310:
1.1 deraadt 311: /* Sets the connection into non-blocking mode. */
312:
1.2 provos 313: void
1.73 itojun 314: packet_set_nonblocking(void)
1.1 deraadt 315: {
1.14 markus 316: /* Set the socket into non-blocking mode. */
317: if (fcntl(connection_in, F_SETFL, O_NONBLOCK) < 0)
318: error("fcntl O_NONBLOCK: %.100s", strerror(errno));
319:
320: if (connection_out != connection_in) {
321: if (fcntl(connection_out, F_SETFL, O_NONBLOCK) < 0)
322: error("fcntl O_NONBLOCK: %.100s", strerror(errno));
323: }
1.1 deraadt 324: }
325:
326: /* Returns the socket used for reading. */
327:
1.2 provos 328: int
1.73 itojun 329: packet_get_connection_in(void)
1.1 deraadt 330: {
1.14 markus 331: return connection_in;
1.1 deraadt 332: }
333:
334: /* Returns the descriptor used for writing. */
335:
1.2 provos 336: int
1.73 itojun 337: packet_get_connection_out(void)
1.1 deraadt 338: {
1.14 markus 339: return connection_out;
1.1 deraadt 340: }
341:
342: /* Closes the connection and clears and frees internal data structures. */
343:
1.2 provos 344: void
1.73 itojun 345: packet_close(void)
1.1 deraadt 346: {
1.14 markus 347: if (!initialized)
348: return;
349: initialized = 0;
350: if (connection_in == connection_out) {
351: shutdown(connection_out, SHUT_RDWR);
352: close(connection_out);
353: } else {
354: close(connection_in);
355: close(connection_out);
356: }
357: buffer_free(&input);
358: buffer_free(&output);
359: buffer_free(&outgoing_packet);
360: buffer_free(&incoming_packet);
1.60 markus 361: if (compression_buffer_ready) {
1.14 markus 362: buffer_free(&compression_buffer);
363: buffer_compress_uninit();
364: }
1.88 markus 365: cipher_cleanup(&send_context);
366: cipher_cleanup(&receive_context);
1.1 deraadt 367: }
368:
369: /* Sets remote side protocol flags. */
370:
1.2 provos 371: void
1.40 markus 372: packet_set_protocol_flags(u_int protocol_flags)
1.1 deraadt 373: {
1.14 markus 374: remote_protocol_flags = protocol_flags;
1.1 deraadt 375: }
376:
377: /* Returns the remote protocol flags set earlier by the above function. */
378:
1.40 markus 379: u_int
1.73 itojun 380: packet_get_protocol_flags(void)
1.1 deraadt 381: {
1.14 markus 382: return remote_protocol_flags;
1.1 deraadt 383: }
384:
1.16 markus 385: /*
386: * Starts packet compression from the next packet on in both directions.
387: * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip.
388: */
1.1 deraadt 389:
1.68 itojun 390: static void
391: packet_init_compression(void)
1.60 markus 392: {
393: if (compression_buffer_ready == 1)
394: return;
395: compression_buffer_ready = 1;
396: buffer_init(&compression_buffer);
397: }
398:
1.2 provos 399: void
400: packet_start_compression(int level)
1.1 deraadt 401: {
1.62 markus 402: if (packet_compression && !compat20)
1.14 markus 403: fatal("Compression already enabled.");
404: packet_compression = 1;
1.60 markus 405: packet_init_compression();
406: buffer_compress_init_send(level);
407: buffer_compress_init_recv();
1.1 deraadt 408: }
409:
1.16 markus 410: /*
411: * Causes any further packets to be encrypted using the given key. The same
412: * key is used for both sending and reception. However, both directions are
413: * encrypted independently of each other.
414: */
1.95 markus 415:
1.2 provos 416: void
1.40 markus 417: packet_set_encryption_key(const u_char *key, u_int keylen,
1.37 markus 418: int number)
1.1 deraadt 419: {
1.37 markus 420: Cipher *cipher = cipher_by_number(number);
1.97 deraadt 421:
1.37 markus 422: if (cipher == NULL)
423: fatal("packet_set_encryption_key: unknown cipher number %d", number);
1.25 markus 424: if (keylen < 20)
1.37 markus 425: fatal("packet_set_encryption_key: keylen too small: %d", keylen);
1.95 markus 426: if (keylen > SSH_SESSION_KEY_LENGTH)
427: fatal("packet_set_encryption_key: keylen too big: %d", keylen);
428: memcpy(ssh1_key, key, keylen);
429: ssh1_keylen = keylen;
1.88 markus 430: cipher_init(&send_context, cipher, key, keylen, NULL, 0, CIPHER_ENCRYPT);
431: cipher_init(&receive_context, cipher, key, keylen, NULL, 0, CIPHER_DECRYPT);
1.95 markus 432: }
433:
434: u_int
435: packet_get_encryption_key(u_char *key)
436: {
437: if (key == NULL)
438: return (ssh1_keylen);
439: memcpy(key, ssh1_key, ssh1_keylen);
440: return (ssh1_keylen);
1.1 deraadt 441: }
442:
1.62 markus 443: /* Start constructing a packet to send. */
1.2 provos 444: void
1.62 markus 445: packet_start(u_char type)
1.1 deraadt 446: {
1.62 markus 447: u_char buf[9];
448: int len;
1.1 deraadt 449:
1.62 markus 450: DBG(debug("packet_start[%d]", type));
451: len = compat20 ? 6 : 9;
452: memset(buf, 0, len - 1);
453: buf[len - 1] = type;
1.14 markus 454: buffer_clear(&outgoing_packet);
1.62 markus 455: buffer_append(&outgoing_packet, buf, len);
1.25 markus 456: }
457:
1.62 markus 458: /* Append payload. */
1.2 provos 459: void
460: packet_put_char(int value)
1.1 deraadt 461: {
1.14 markus 462: char ch = value;
1.97 deraadt 463:
1.14 markus 464: buffer_append(&outgoing_packet, &ch, 1);
1.1 deraadt 465: }
1.2 provos 466: void
1.40 markus 467: packet_put_int(u_int value)
1.1 deraadt 468: {
1.14 markus 469: buffer_put_int(&outgoing_packet, value);
1.1 deraadt 470: }
1.2 provos 471: void
1.76 stevesk 472: packet_put_string(const void *buf, u_int len)
1.1 deraadt 473: {
1.14 markus 474: buffer_put_string(&outgoing_packet, buf, len);
1.1 deraadt 475: }
1.24 markus 476: void
477: packet_put_cstring(const char *str)
478: {
1.65 markus 479: buffer_put_cstring(&outgoing_packet, str);
1.24 markus 480: }
481: void
1.76 stevesk 482: packet_put_raw(const void *buf, u_int len)
1.24 markus 483: {
484: buffer_append(&outgoing_packet, buf, len);
485: }
1.2 provos 486: void
1.14 markus 487: packet_put_bignum(BIGNUM * value)
1.1 deraadt 488: {
1.14 markus 489: buffer_put_bignum(&outgoing_packet, value);
1.1 deraadt 490: }
1.24 markus 491: void
492: packet_put_bignum2(BIGNUM * value)
493: {
494: buffer_put_bignum2(&outgoing_packet, value);
495: }
1.1 deraadt 496:
1.16 markus 497: /*
498: * Finalizes and sends the packet. If the encryption key has been set,
499: * encrypts the packet before sending.
500: */
1.14 markus 501:
1.68 itojun 502: static void
1.49 itojun 503: packet_send1(void)
1.1 deraadt 504: {
1.89 markus 505: u_char buf[8], *cp;
1.14 markus 506: int i, padding, len;
1.40 markus 507: u_int checksum;
1.14 markus 508: u_int32_t rand = 0;
509:
1.16 markus 510: /*
511: * If using packet compression, compress the payload of the outgoing
512: * packet.
513: */
1.14 markus 514: if (packet_compression) {
515: buffer_clear(&compression_buffer);
516: /* Skip padding. */
517: buffer_consume(&outgoing_packet, 8);
518: /* padding */
519: buffer_append(&compression_buffer, "\0\0\0\0\0\0\0\0", 8);
520: buffer_compress(&outgoing_packet, &compression_buffer);
521: buffer_clear(&outgoing_packet);
522: buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer),
1.75 deraadt 523: buffer_len(&compression_buffer));
1.14 markus 524: }
525: /* Compute packet length without padding (add checksum, remove padding). */
526: len = buffer_len(&outgoing_packet) + 4 - 8;
527:
1.32 markus 528: /* Insert padding. Initialized to zero in packet_start1() */
1.14 markus 529: padding = 8 - len % 8;
1.88 markus 530: if (!send_context.plaintext) {
1.14 markus 531: cp = buffer_ptr(&outgoing_packet);
532: for (i = 0; i < padding; i++) {
533: if (i % 4 == 0)
534: rand = arc4random();
535: cp[7 - i] = rand & 0xff;
536: rand >>= 8;
537: }
538: }
539: buffer_consume(&outgoing_packet, 8 - padding);
540:
541: /* Add check bytes. */
1.83 stevesk 542: checksum = ssh_crc32(buffer_ptr(&outgoing_packet),
1.34 deraadt 543: buffer_len(&outgoing_packet));
1.14 markus 544: PUT_32BIT(buf, checksum);
545: buffer_append(&outgoing_packet, buf, 4);
1.1 deraadt 546:
547: #ifdef PACKET_DEBUG
1.14 markus 548: fprintf(stderr, "packet_send plain: ");
549: buffer_dump(&outgoing_packet);
1.1 deraadt 550: #endif
551:
1.14 markus 552: /* Append to output. */
553: PUT_32BIT(buf, len);
554: buffer_append(&output, buf, 4);
1.76 stevesk 555: cp = buffer_append_space(&output, buffer_len(&outgoing_packet));
1.88 markus 556: cipher_crypt(&send_context, cp, buffer_ptr(&outgoing_packet),
1.75 deraadt 557: buffer_len(&outgoing_packet));
1.14 markus 558:
1.1 deraadt 559: #ifdef PACKET_DEBUG
1.14 markus 560: fprintf(stderr, "encrypted: ");
561: buffer_dump(&output);
1.1 deraadt 562: #endif
563:
1.14 markus 564: buffer_clear(&outgoing_packet);
1.1 deraadt 565:
1.16 markus 566: /*
567: * Note that the packet is now only buffered in output. It won\'t be
568: * actually sent until packet_write_wait or packet_write_poll is
569: * called.
570: */
1.1 deraadt 571: }
572:
1.91 markus 573: void
1.57 markus 574: set_newkeys(int mode)
575: {
576: Enc *enc;
577: Mac *mac;
578: Comp *comp;
579: CipherContext *cc;
1.105 ! markus 580: u_int64_t *max_blocks;
1.88 markus 581: int encrypt;
1.57 markus 582:
1.100 markus 583: debug2("set_newkeys: mode %d", mode);
1.57 markus 584:
1.88 markus 585: if (mode == MODE_OUT) {
586: cc = &send_context;
587: encrypt = CIPHER_ENCRYPT;
1.105 ! markus 588: p_send.packets = p_send.blocks = 0;
! 589: max_blocks = &max_blocks_out;
1.88 markus 590: } else {
591: cc = &receive_context;
592: encrypt = CIPHER_DECRYPT;
1.105 ! markus 593: p_read.packets = p_read.blocks = 0;
! 594: max_blocks = &max_blocks_in;
1.88 markus 595: }
1.57 markus 596: if (newkeys[mode] != NULL) {
1.100 markus 597: debug("set_newkeys: rekeying");
1.88 markus 598: cipher_cleanup(cc);
1.59 markus 599: enc = &newkeys[mode]->enc;
600: mac = &newkeys[mode]->mac;
601: comp = &newkeys[mode]->comp;
1.61 markus 602: memset(mac->key, 0, mac->key_len);
1.59 markus 603: xfree(enc->name);
604: xfree(enc->iv);
605: xfree(enc->key);
606: xfree(mac->name);
607: xfree(mac->key);
608: xfree(comp->name);
1.58 markus 609: xfree(newkeys[mode]);
1.57 markus 610: }
611: newkeys[mode] = kex_get_newkeys(mode);
612: if (newkeys[mode] == NULL)
613: fatal("newkeys: no keys for mode %d", mode);
614: enc = &newkeys[mode]->enc;
615: mac = &newkeys[mode]->mac;
616: comp = &newkeys[mode]->comp;
617: if (mac->md != NULL)
618: mac->enabled = 1;
619: DBG(debug("cipher_init_context: %d", mode));
1.88 markus 620: cipher_init(cc, enc->cipher, enc->key, enc->key_len,
621: enc->iv, enc->block_size, encrypt);
1.91 markus 622: /* Deleting the keys does not gain extra security */
623: /* memset(enc->iv, 0, enc->block_size);
624: memset(enc->key, 0, enc->key_len); */
1.57 markus 625: if (comp->type != 0 && comp->enabled == 0) {
1.60 markus 626: packet_init_compression();
627: if (mode == MODE_OUT)
628: buffer_compress_init_send(6);
629: else
630: buffer_compress_init_recv();
1.57 markus 631: comp->enabled = 1;
632: }
1.105 ! markus 633: *max_blocks = ((u_int64_t)1 << (enc->block_size*2));
! 634: if (rekey_limit)
! 635: *max_blocks = MIN(*max_blocks, rekey_limit / enc->block_size);
1.57 markus 636: }
637:
1.16 markus 638: /*
1.25 markus 639: * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue)
640: */
1.68 itojun 641: static void
1.105 ! markus 642: packet_send2_wrapped(void)
1.25 markus 643: {
1.89 markus 644: u_char type, *cp, *macbuf = NULL;
1.71 markus 645: u_char padlen, pad;
1.40 markus 646: u_int packet_length = 0;
1.71 markus 647: u_int i, len;
1.25 markus 648: u_int32_t rand = 0;
649: Enc *enc = NULL;
650: Mac *mac = NULL;
651: Comp *comp = NULL;
652: int block_size;
653:
1.57 markus 654: if (newkeys[MODE_OUT] != NULL) {
655: enc = &newkeys[MODE_OUT]->enc;
656: mac = &newkeys[MODE_OUT]->mac;
657: comp = &newkeys[MODE_OUT]->comp;
1.25 markus 658: }
1.88 markus 659: block_size = enc ? enc->block_size : 8;
1.25 markus 660:
1.89 markus 661: cp = buffer_ptr(&outgoing_packet);
662: type = cp[5];
1.25 markus 663:
664: #ifdef PACKET_DEBUG
665: fprintf(stderr, "plain: ");
666: buffer_dump(&outgoing_packet);
667: #endif
668:
669: if (comp && comp->enabled) {
670: len = buffer_len(&outgoing_packet);
671: /* skip header, compress only payload */
672: buffer_consume(&outgoing_packet, 5);
673: buffer_clear(&compression_buffer);
674: buffer_compress(&outgoing_packet, &compression_buffer);
675: buffer_clear(&outgoing_packet);
676: buffer_append(&outgoing_packet, "\0\0\0\0\0", 5);
677: buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer),
678: buffer_len(&compression_buffer));
679: DBG(debug("compression: raw %d compressed %d", len,
680: buffer_len(&outgoing_packet)));
681: }
682:
683: /* sizeof (packet_len + pad_len + payload) */
684: len = buffer_len(&outgoing_packet);
685:
686: /*
687: * calc size of padding, alloc space, get random data,
688: * minimum padding is 4 bytes
689: */
690: padlen = block_size - (len % block_size);
691: if (padlen < 4)
692: padlen += block_size;
1.71 markus 693: if (extra_pad) {
694: /* will wrap if extra_pad+padlen > 255 */
695: extra_pad = roundup(extra_pad, block_size);
696: pad = extra_pad - ((len + padlen) % extra_pad);
1.93 markus 697: debug3("packet_send2: adding %d (len %d padlen %d extra_pad %d)",
1.71 markus 698: pad, len, padlen, extra_pad);
699: padlen += pad;
700: extra_pad = 0;
701: }
1.76 stevesk 702: cp = buffer_append_space(&outgoing_packet, padlen);
1.88 markus 703: if (enc && !send_context.plaintext) {
1.32 markus 704: /* random padding */
1.25 markus 705: for (i = 0; i < padlen; i++) {
706: if (i % 4 == 0)
707: rand = arc4random();
708: cp[i] = rand & 0xff;
1.52 markus 709: rand >>= 8;
1.25 markus 710: }
1.32 markus 711: } else {
712: /* clear padding */
713: memset(cp, 0, padlen);
1.25 markus 714: }
715: /* packet_length includes payload, padding and padding length field */
716: packet_length = buffer_len(&outgoing_packet) - 4;
1.89 markus 717: cp = buffer_ptr(&outgoing_packet);
718: PUT_32BIT(cp, packet_length);
719: cp[4] = padlen;
1.25 markus 720: DBG(debug("send: len %d (includes padlen %d)", packet_length+4, padlen));
721:
722: /* compute MAC over seqnr and packet(length fields, payload, padding) */
723: if (mac && mac->enabled) {
1.105 ! markus 724: macbuf = mac_compute(mac, p_send.seqnr,
1.83 stevesk 725: buffer_ptr(&outgoing_packet),
1.50 markus 726: buffer_len(&outgoing_packet));
1.105 ! markus 727: DBG(debug("done calc MAC out #%d", p_send.seqnr));
1.25 markus 728: }
729: /* encrypt packet and append to output buffer. */
1.76 stevesk 730: cp = buffer_append_space(&output, buffer_len(&outgoing_packet));
1.88 markus 731: cipher_crypt(&send_context, cp, buffer_ptr(&outgoing_packet),
1.25 markus 732: buffer_len(&outgoing_packet));
733: /* append unencrypted MAC */
734: if (mac && mac->enabled)
735: buffer_append(&output, (char *)macbuf, mac->mac_len);
736: #ifdef PACKET_DEBUG
737: fprintf(stderr, "encrypted: ");
738: buffer_dump(&output);
739: #endif
1.29 markus 740: /* increment sequence number for outgoing packets */
1.105 ! markus 741: if (++p_send.seqnr == 0)
1.29 markus 742: log("outgoing seqnr wraps around");
1.105 ! markus 743: if (++p_send.packets == 0)
! 744: if (!(datafellows & SSH_BUG_NOREKEY))
! 745: fatal("XXX too many packets with same key");
! 746: p_send.blocks += (packet_length + 4) / block_size;
1.25 markus 747: buffer_clear(&outgoing_packet);
748:
1.57 markus 749: if (type == SSH2_MSG_NEWKEYS)
750: set_newkeys(MODE_OUT);
1.25 markus 751: }
752:
1.105 ! markus 753: static void
! 754: packet_send2(void)
! 755: {
! 756: static int rekeying = 0;
! 757: struct packet *p;
! 758: u_char type, *cp;
! 759:
! 760: cp = buffer_ptr(&outgoing_packet);
! 761: type = cp[5];
! 762:
! 763: /* during rekeying we can only send key exchange messages */
! 764: if (rekeying) {
! 765: if (!((type >= SSH2_MSG_TRANSPORT_MIN) &&
! 766: (type <= SSH2_MSG_TRANSPORT_MAX))) {
! 767: debug("enqueue packet: %u", type);
! 768: p = xmalloc(sizeof(*p));
! 769: p->type = type;
! 770: memcpy(&p->payload, &outgoing_packet, sizeof(Buffer));
! 771: buffer_init(&outgoing_packet);
! 772: TAILQ_INSERT_TAIL(&outgoing, p, next);
! 773: return;
! 774: }
! 775: }
! 776:
! 777: /* rekeying starts with sending KEXINIT */
! 778: if (type == SSH2_MSG_KEXINIT)
! 779: rekeying = 1;
! 780:
! 781: packet_send2_wrapped();
! 782:
! 783: /* after a NEWKEYS message we can send the complete queue */
! 784: if (type == SSH2_MSG_NEWKEYS) {
! 785: rekeying = 0;
! 786: while ((p = TAILQ_FIRST(&outgoing))) {
! 787: type = p->type;
! 788: debug("dequeue packet: %u", type);
! 789: buffer_free(&outgoing_packet);
! 790: memcpy(&outgoing_packet, &p->payload,
! 791: sizeof(Buffer));
! 792: TAILQ_REMOVE(&outgoing, p, next);
! 793: xfree(p);
! 794: packet_send2_wrapped();
! 795: }
! 796: }
! 797: }
! 798:
1.25 markus 799: void
1.73 itojun 800: packet_send(void)
1.25 markus 801: {
1.62 markus 802: if (compat20)
1.25 markus 803: packet_send2();
804: else
805: packet_send1();
806: DBG(debug("packet_send done"));
807: }
808:
809: /*
1.16 markus 810: * Waits until a packet has been received, and returns its type. Note that
811: * no other data is processed until this returns, so this function should not
812: * be used during the interactive session.
813: */
1.1 deraadt 814:
1.2 provos 815: int
1.82 markus 816: packet_read_seqnr(u_int32_t *seqnr_p)
1.1 deraadt 817: {
1.14 markus 818: int type, len;
1.56 millert 819: fd_set *setp;
1.14 markus 820: char buf[8192];
1.25 markus 821: DBG(debug("packet_read()"));
1.14 markus 822:
1.56 millert 823: setp = (fd_set *)xmalloc(howmany(connection_in+1, NFDBITS) *
824: sizeof(fd_mask));
825:
1.14 markus 826: /* Since we are blocking, ensure that all written packets have been sent. */
827: packet_write_wait();
828:
829: /* Stay in the loop until we have received a complete packet. */
830: for (;;) {
831: /* Try to read a packet from the buffer. */
1.82 markus 832: type = packet_read_poll_seqnr(seqnr_p);
1.62 markus 833: if (!compat20 && (
1.32 markus 834: type == SSH_SMSG_SUCCESS
1.14 markus 835: || type == SSH_SMSG_FAILURE
836: || type == SSH_CMSG_EOF
1.32 markus 837: || type == SSH_CMSG_EXIT_CONFIRMATION))
1.79 markus 838: packet_check_eom();
1.14 markus 839: /* If we got a packet, return it. */
1.56 millert 840: if (type != SSH_MSG_NONE) {
841: xfree(setp);
1.14 markus 842: return type;
1.56 millert 843: }
1.16 markus 844: /*
845: * Otherwise, wait for some data to arrive, add it to the
846: * buffer, and try again.
847: */
1.56 millert 848: memset(setp, 0, howmany(connection_in + 1, NFDBITS) *
849: sizeof(fd_mask));
850: FD_SET(connection_in, setp);
1.16 markus 851:
1.14 markus 852: /* Wait for some data to arrive. */
1.56 millert 853: while (select(connection_in + 1, setp, NULL, NULL, NULL) == -1 &&
1.51 deraadt 854: (errno == EAGAIN || errno == EINTR))
855: ;
1.16 markus 856:
1.14 markus 857: /* Read data from the socket. */
858: len = read(connection_in, buf, sizeof(buf));
1.18 markus 859: if (len == 0) {
860: log("Connection closed by %.200s", get_remote_ipaddr());
861: fatal_cleanup();
862: }
1.14 markus 863: if (len < 0)
864: fatal("Read from socket failed: %.100s", strerror(errno));
865: /* Append it to the buffer. */
866: packet_process_incoming(buf, len);
867: }
868: /* NOTREACHED */
1.1 deraadt 869: }
870:
1.77 djm 871: int
1.82 markus 872: packet_read(void)
1.77 djm 873: {
1.82 markus 874: return packet_read_seqnr(NULL);
1.77 djm 875: }
876:
1.16 markus 877: /*
878: * Waits until a packet has been received, verifies that its type matches
879: * that given, and gives a fatal error and exits if there is a mismatch.
880: */
1.1 deraadt 881:
1.2 provos 882: void
1.82 markus 883: packet_read_expect(int expected_type)
1.1 deraadt 884: {
1.14 markus 885: int type;
1.1 deraadt 886:
1.82 markus 887: type = packet_read();
1.14 markus 888: if (type != expected_type)
889: packet_disconnect("Protocol error: expected packet type %d, got %d",
1.25 markus 890: expected_type, type);
1.1 deraadt 891: }
892:
893: /* Checks if a full packet is available in the data received so far via
1.14 markus 894: * packet_process_incoming. If so, reads the packet; otherwise returns
895: * SSH_MSG_NONE. This does not wait for data from the connection.
896: *
897: * SSH_MSG_DISCONNECT is handled specially here. Also,
898: * SSH_MSG_IGNORE messages are skipped by this function and are never returned
899: * to higher levels.
900: */
1.1 deraadt 901:
1.68 itojun 902: static int
1.82 markus 903: packet_read_poll1(void)
1.1 deraadt 904: {
1.40 markus 905: u_int len, padded_len;
1.89 markus 906: u_char *cp, type;
1.40 markus 907: u_int checksum, stored_checksum;
1.14 markus 908:
909: /* Check if input size is less than minimum packet size. */
910: if (buffer_len(&input) < 4 + 8)
911: return SSH_MSG_NONE;
912: /* Get length of incoming packet. */
1.89 markus 913: cp = buffer_ptr(&input);
914: len = GET_32BIT(cp);
1.14 markus 915: if (len < 1 + 2 + 2 || len > 256 * 1024)
1.98 markus 916: packet_disconnect("Bad packet length %u.", len);
1.14 markus 917: padded_len = (len + 8) & ~7;
918:
919: /* Check if the packet has been entirely received. */
920: if (buffer_len(&input) < 4 + padded_len)
921: return SSH_MSG_NONE;
922:
923: /* The entire packet is in buffer. */
924:
925: /* Consume packet length. */
926: buffer_consume(&input, 4);
927:
1.62 markus 928: /*
929: * Cryptographic attack detector for ssh
930: * (C)1998 CORE-SDI, Buenos Aires Argentina
931: * Ariel Futoransky(futo@core-sdi.com)
932: */
1.88 markus 933: if (!receive_context.plaintext &&
1.62 markus 934: detect_attack(buffer_ptr(&input), padded_len, NULL) == DEATTACK_DETECTED)
935: packet_disconnect("crc32 compensation attack: network attack detected");
936:
937: /* Decrypt data to incoming_packet. */
1.14 markus 938: buffer_clear(&incoming_packet);
1.76 stevesk 939: cp = buffer_append_space(&incoming_packet, padded_len);
1.88 markus 940: cipher_crypt(&receive_context, cp, buffer_ptr(&input), padded_len);
1.62 markus 941:
1.14 markus 942: buffer_consume(&input, padded_len);
1.1 deraadt 943:
944: #ifdef PACKET_DEBUG
1.14 markus 945: fprintf(stderr, "read_poll plain: ");
946: buffer_dump(&incoming_packet);
1.1 deraadt 947: #endif
948:
1.14 markus 949: /* Compute packet checksum. */
1.83 stevesk 950: checksum = ssh_crc32(buffer_ptr(&incoming_packet),
1.25 markus 951: buffer_len(&incoming_packet) - 4);
1.14 markus 952:
953: /* Skip padding. */
954: buffer_consume(&incoming_packet, 8 - len % 8);
955:
956: /* Test check bytes. */
957: if (len != buffer_len(&incoming_packet))
1.77 djm 958: packet_disconnect("packet_read_poll1: len %d != buffer_len %d.",
1.25 markus 959: len, buffer_len(&incoming_packet));
1.14 markus 960:
1.89 markus 961: cp = (u_char *)buffer_ptr(&incoming_packet) + len - 4;
962: stored_checksum = GET_32BIT(cp);
1.14 markus 963: if (checksum != stored_checksum)
964: packet_disconnect("Corrupted check bytes on input.");
965: buffer_consume_end(&incoming_packet, 4);
966:
967: if (packet_compression) {
968: buffer_clear(&compression_buffer);
969: buffer_uncompress(&incoming_packet, &compression_buffer);
970: buffer_clear(&incoming_packet);
971: buffer_append(&incoming_packet, buffer_ptr(&compression_buffer),
1.25 markus 972: buffer_len(&compression_buffer));
1.14 markus 973: }
1.62 markus 974: type = buffer_get_char(&incoming_packet);
975: return type;
1.1 deraadt 976: }
1.14 markus 977:
1.68 itojun 978: static int
1.82 markus 979: packet_read_poll2(u_int32_t *seqnr_p)
1.25 markus 980: {
1.50 markus 981: static u_int packet_length = 0;
1.40 markus 982: u_int padlen, need;
1.89 markus 983: u_char *macbuf, *cp, type;
1.25 markus 984: int maclen, block_size;
985: Enc *enc = NULL;
986: Mac *mac = NULL;
987: Comp *comp = NULL;
988:
1.57 markus 989: if (newkeys[MODE_IN] != NULL) {
990: enc = &newkeys[MODE_IN]->enc;
991: mac = &newkeys[MODE_IN]->mac;
992: comp = &newkeys[MODE_IN]->comp;
1.25 markus 993: }
994: maclen = mac && mac->enabled ? mac->mac_len : 0;
1.88 markus 995: block_size = enc ? enc->block_size : 8;
1.25 markus 996:
997: if (packet_length == 0) {
998: /*
999: * check if input size is less than the cipher block size,
1000: * decrypt first block and extract length of incoming packet
1001: */
1002: if (buffer_len(&input) < block_size)
1003: return SSH_MSG_NONE;
1004: buffer_clear(&incoming_packet);
1.76 stevesk 1005: cp = buffer_append_space(&incoming_packet, block_size);
1.88 markus 1006: cipher_crypt(&receive_context, cp, buffer_ptr(&input),
1.25 markus 1007: block_size);
1.89 markus 1008: cp = buffer_ptr(&incoming_packet);
1009: packet_length = GET_32BIT(cp);
1.25 markus 1010: if (packet_length < 1 + 4 || packet_length > 256 * 1024) {
1011: buffer_dump(&incoming_packet);
1.98 markus 1012: packet_disconnect("Bad packet length %u.", packet_length);
1.25 markus 1013: }
1.98 markus 1014: DBG(debug("input: packet len %u", packet_length+4));
1.25 markus 1015: buffer_consume(&input, block_size);
1016: }
1017: /* we have a partial packet of block_size bytes */
1018: need = 4 + packet_length - block_size;
1019: DBG(debug("partial packet %d, need %d, maclen %d", block_size,
1020: need, maclen));
1021: if (need % block_size != 0)
1022: fatal("padding error: need %d block %d mod %d",
1023: need, block_size, need % block_size);
1024: /*
1025: * check if the entire packet has been received and
1026: * decrypt into incoming_packet
1027: */
1028: if (buffer_len(&input) < need + maclen)
1029: return SSH_MSG_NONE;
1030: #ifdef PACKET_DEBUG
1031: fprintf(stderr, "read_poll enc/full: ");
1032: buffer_dump(&input);
1033: #endif
1.76 stevesk 1034: cp = buffer_append_space(&incoming_packet, need);
1.88 markus 1035: cipher_crypt(&receive_context, cp, buffer_ptr(&input), need);
1.25 markus 1036: buffer_consume(&input, need);
1037: /*
1038: * compute MAC over seqnr and packet,
1039: * increment sequence number for incoming packet
1040: */
1.29 markus 1041: if (mac && mac->enabled) {
1.105 ! markus 1042: macbuf = mac_compute(mac, p_read.seqnr,
1.83 stevesk 1043: buffer_ptr(&incoming_packet),
1.50 markus 1044: buffer_len(&incoming_packet));
1.25 markus 1045: if (memcmp(macbuf, buffer_ptr(&input), mac->mac_len) != 0)
1.36 markus 1046: packet_disconnect("Corrupted MAC on input.");
1.105 ! markus 1047: DBG(debug("MAC #%d ok", p_read.seqnr));
1.25 markus 1048: buffer_consume(&input, mac->mac_len);
1049: }
1.77 djm 1050: if (seqnr_p != NULL)
1.105 ! markus 1051: *seqnr_p = p_read.seqnr;
! 1052: if (++p_read.seqnr == 0)
1.29 markus 1053: log("incoming seqnr wraps around");
1.105 ! markus 1054: if (++p_read.packets == 0)
! 1055: if (!(datafellows & SSH_BUG_NOREKEY))
! 1056: fatal("XXX too many packets with same key");
! 1057: p_read.blocks += (packet_length + 4) / block_size;
1.25 markus 1058:
1059: /* get padlen */
1.76 stevesk 1060: cp = buffer_ptr(&incoming_packet);
1.89 markus 1061: padlen = cp[4];
1.25 markus 1062: DBG(debug("input: padlen %d", padlen));
1063: if (padlen < 4)
1064: packet_disconnect("Corrupted padlen %d on input.", padlen);
1065:
1066: /* skip packet size + padlen, discard padding */
1067: buffer_consume(&incoming_packet, 4 + 1);
1068: buffer_consume_end(&incoming_packet, padlen);
1069:
1070: DBG(debug("input: len before de-compress %d", buffer_len(&incoming_packet)));
1071: if (comp && comp->enabled) {
1072: buffer_clear(&compression_buffer);
1073: buffer_uncompress(&incoming_packet, &compression_buffer);
1074: buffer_clear(&incoming_packet);
1075: buffer_append(&incoming_packet, buffer_ptr(&compression_buffer),
1076: buffer_len(&compression_buffer));
1.97 deraadt 1077: DBG(debug("input: len after de-compress %d",
1078: buffer_len(&incoming_packet)));
1.25 markus 1079: }
1080: /*
1081: * get packet type, implies consume.
1082: * return length of payload (without type field)
1083: */
1.62 markus 1084: type = buffer_get_char(&incoming_packet);
1.57 markus 1085: if (type == SSH2_MSG_NEWKEYS)
1086: set_newkeys(MODE_IN);
1.25 markus 1087: #ifdef PACKET_DEBUG
1.55 deraadt 1088: fprintf(stderr, "read/plain[%d]:\r\n", type);
1.25 markus 1089: buffer_dump(&incoming_packet);
1090: #endif
1.62 markus 1091: /* reset for next packet */
1092: packet_length = 0;
1093: return type;
1.25 markus 1094: }
1095:
1096: int
1.82 markus 1097: packet_read_poll_seqnr(u_int32_t *seqnr_p)
1.25 markus 1098: {
1.96 deraadt 1099: u_int reason, seqnr;
1.62 markus 1100: u_char type;
1.25 markus 1101: char *msg;
1.62 markus 1102:
1.25 markus 1103: for (;;) {
1.62 markus 1104: if (compat20) {
1.82 markus 1105: type = packet_read_poll2(seqnr_p);
1.62 markus 1106: if (type)
1.25 markus 1107: DBG(debug("received packet type %d", type));
1.74 deraadt 1108: switch (type) {
1.25 markus 1109: case SSH2_MSG_IGNORE:
1110: break;
1111: case SSH2_MSG_DEBUG:
1112: packet_get_char();
1113: msg = packet_get_string(NULL);
1114: debug("Remote: %.900s", msg);
1115: xfree(msg);
1116: msg = packet_get_string(NULL);
1117: xfree(msg);
1118: break;
1119: case SSH2_MSG_DISCONNECT:
1120: reason = packet_get_int();
1121: msg = packet_get_string(NULL);
1.96 deraadt 1122: log("Received disconnect from %s: %u: %.400s",
1123: get_remote_ipaddr(), reason, msg);
1.25 markus 1124: xfree(msg);
1125: fatal_cleanup();
1.84 markus 1126: break;
1127: case SSH2_MSG_UNIMPLEMENTED:
1128: seqnr = packet_get_int();
1.96 deraadt 1129: debug("Received SSH2_MSG_UNIMPLEMENTED for %u",
1130: seqnr);
1.25 markus 1131: break;
1132: default:
1133: return type;
1134: break;
1.48 stevesk 1135: }
1.25 markus 1136: } else {
1.82 markus 1137: type = packet_read_poll1();
1.74 deraadt 1138: switch (type) {
1.25 markus 1139: case SSH_MSG_IGNORE:
1140: break;
1141: case SSH_MSG_DEBUG:
1142: msg = packet_get_string(NULL);
1143: debug("Remote: %.900s", msg);
1144: xfree(msg);
1145: break;
1146: case SSH_MSG_DISCONNECT:
1147: msg = packet_get_string(NULL);
1.96 deraadt 1148: log("Received disconnect from %s: %.400s",
1149: get_remote_ipaddr(), msg);
1.25 markus 1150: fatal_cleanup();
1151: xfree(msg);
1152: break;
1153: default:
1.62 markus 1154: if (type)
1.25 markus 1155: DBG(debug("received packet type %d", type));
1156: return type;
1157: break;
1.48 stevesk 1158: }
1.25 markus 1159: }
1160: }
1.77 djm 1161: }
1162:
1163: int
1.82 markus 1164: packet_read_poll(void)
1.77 djm 1165: {
1.82 markus 1166: return packet_read_poll_seqnr(NULL);
1.25 markus 1167: }
1168:
1.16 markus 1169: /*
1170: * Buffers the given amount of input characters. This is intended to be used
1171: * together with packet_read_poll.
1172: */
1.1 deraadt 1173:
1.2 provos 1174: void
1.40 markus 1175: packet_process_incoming(const char *buf, u_int len)
1.1 deraadt 1176: {
1.14 markus 1177: buffer_append(&input, buf, len);
1.1 deraadt 1178: }
1179:
1180: /* Returns a character from the packet. */
1181:
1.40 markus 1182: u_int
1.73 itojun 1183: packet_get_char(void)
1.1 deraadt 1184: {
1.14 markus 1185: char ch;
1.97 deraadt 1186:
1.14 markus 1187: buffer_get(&incoming_packet, &ch, 1);
1.40 markus 1188: return (u_char) ch;
1.1 deraadt 1189: }
1190:
1191: /* Returns an integer from the packet data. */
1192:
1.40 markus 1193: u_int
1.73 itojun 1194: packet_get_int(void)
1.1 deraadt 1195: {
1.14 markus 1196: return buffer_get_int(&incoming_packet);
1.1 deraadt 1197: }
1198:
1.16 markus 1199: /*
1200: * Returns an arbitrary precision integer from the packet data. The integer
1201: * must have been initialized before this call.
1202: */
1.1 deraadt 1203:
1.2 provos 1204: void
1.80 markus 1205: packet_get_bignum(BIGNUM * value)
1.1 deraadt 1206: {
1.81 markus 1207: buffer_get_bignum(&incoming_packet, value);
1.24 markus 1208: }
1209:
1210: void
1.80 markus 1211: packet_get_bignum2(BIGNUM * value)
1.24 markus 1212: {
1.81 markus 1213: buffer_get_bignum2(&incoming_packet, value);
1.24 markus 1214: }
1215:
1.76 stevesk 1216: void *
1.24 markus 1217: packet_get_raw(int *length_ptr)
1218: {
1219: int bytes = buffer_len(&incoming_packet);
1.97 deraadt 1220:
1.24 markus 1221: if (length_ptr != NULL)
1222: *length_ptr = bytes;
1223: return buffer_ptr(&incoming_packet);
1.28 markus 1224: }
1225:
1226: int
1227: packet_remaining(void)
1228: {
1229: return buffer_len(&incoming_packet);
1.1 deraadt 1230: }
1231:
1.16 markus 1232: /*
1233: * Returns a string from the packet data. The string is allocated using
1234: * xmalloc; it is the responsibility of the calling program to free it when
1235: * no longer needed. The length_ptr argument may be NULL, or point to an
1236: * integer into which the length of the string is stored.
1237: */
1.1 deraadt 1238:
1.76 stevesk 1239: void *
1.40 markus 1240: packet_get_string(u_int *length_ptr)
1.1 deraadt 1241: {
1.14 markus 1242: return buffer_get_string(&incoming_packet, length_ptr);
1.1 deraadt 1243: }
1244:
1.16 markus 1245: /*
1246: * Sends a diagnostic message from the server to the client. This message
1247: * can be sent at any time (but not while constructing another message). The
1248: * message is printed immediately, but only if the client is being executed
1249: * in verbose mode. These messages are primarily intended to ease debugging
1250: * authentication problems. The length of the formatted message must not
1251: * exceed 1024 bytes. This will automatically call packet_write_wait.
1252: */
1.1 deraadt 1253:
1.2 provos 1254: void
1.14 markus 1255: packet_send_debug(const char *fmt,...)
1.1 deraadt 1256: {
1.14 markus 1257: char buf[1024];
1258: va_list args;
1.39 markus 1259:
1260: if (compat20 && (datafellows & SSH_BUG_DEBUG))
1261: return;
1.14 markus 1262:
1263: va_start(args, fmt);
1264: vsnprintf(buf, sizeof(buf), fmt, args);
1265: va_end(args);
1266:
1.30 markus 1267: if (compat20) {
1268: packet_start(SSH2_MSG_DEBUG);
1269: packet_put_char(0); /* bool: always display */
1270: packet_put_cstring(buf);
1271: packet_put_cstring("");
1272: } else {
1273: packet_start(SSH_MSG_DEBUG);
1274: packet_put_cstring(buf);
1275: }
1.14 markus 1276: packet_send();
1277: packet_write_wait();
1.1 deraadt 1278: }
1279:
1.16 markus 1280: /*
1281: * Logs the error plus constructs and sends a disconnect packet, closes the
1282: * connection, and exits. This function never returns. The error message
1283: * should not contain a newline. The length of the formatted message must
1284: * not exceed 1024 bytes.
1285: */
1.1 deraadt 1286:
1.2 provos 1287: void
1.14 markus 1288: packet_disconnect(const char *fmt,...)
1.1 deraadt 1289: {
1.14 markus 1290: char buf[1024];
1291: va_list args;
1292: static int disconnecting = 0;
1.97 deraadt 1293:
1.14 markus 1294: if (disconnecting) /* Guard against recursive invocations. */
1295: fatal("packet_disconnect called recursively.");
1296: disconnecting = 1;
1297:
1.16 markus 1298: /*
1299: * Format the message. Note that the caller must make sure the
1300: * message is of limited size.
1301: */
1.14 markus 1302: va_start(args, fmt);
1303: vsnprintf(buf, sizeof(buf), fmt, args);
1304: va_end(args);
1305:
1.99 markus 1306: /* Display the error locally */
1307: log("Disconnecting: %.100s", buf);
1308:
1.14 markus 1309: /* Send the disconnect message to the other side, and wait for it to get sent. */
1.25 markus 1310: if (compat20) {
1311: packet_start(SSH2_MSG_DISCONNECT);
1312: packet_put_int(SSH2_DISCONNECT_PROTOCOL_ERROR);
1313: packet_put_cstring(buf);
1314: packet_put_cstring("");
1315: } else {
1316: packet_start(SSH_MSG_DISCONNECT);
1.65 markus 1317: packet_put_cstring(buf);
1.25 markus 1318: }
1.14 markus 1319: packet_send();
1320: packet_write_wait();
1321:
1322: /* Stop listening for connections. */
1.67 markus 1323: channel_close_all();
1.14 markus 1324:
1325: /* Close the connection. */
1326: packet_close();
1.1 deraadt 1327:
1.17 markus 1328: fatal_cleanup();
1.1 deraadt 1329: }
1330:
1.16 markus 1331: /* Checks if there is any buffered output, and tries to write some of the output. */
1.1 deraadt 1332:
1.2 provos 1333: void
1.73 itojun 1334: packet_write_poll(void)
1.1 deraadt 1335: {
1.14 markus 1336: int len = buffer_len(&output);
1.97 deraadt 1337:
1.14 markus 1338: if (len > 0) {
1339: len = write(connection_out, buffer_ptr(&output), len);
1340: if (len <= 0) {
1341: if (errno == EAGAIN)
1342: return;
1343: else
1344: fatal("Write failed: %.100s", strerror(errno));
1345: }
1346: buffer_consume(&output, len);
1347: }
1.1 deraadt 1348: }
1349:
1.16 markus 1350: /*
1351: * Calls packet_write_poll repeatedly until all pending output data has been
1352: * written.
1353: */
1.1 deraadt 1354:
1.2 provos 1355: void
1.73 itojun 1356: packet_write_wait(void)
1.1 deraadt 1357: {
1.56 millert 1358: fd_set *setp;
1359:
1360: setp = (fd_set *)xmalloc(howmany(connection_out + 1, NFDBITS) *
1361: sizeof(fd_mask));
1.14 markus 1362: packet_write_poll();
1363: while (packet_have_data_to_write()) {
1.56 millert 1364: memset(setp, 0, howmany(connection_out + 1, NFDBITS) *
1365: sizeof(fd_mask));
1366: FD_SET(connection_out, setp);
1367: while (select(connection_out + 1, NULL, setp, NULL, NULL) == -1 &&
1.51 deraadt 1368: (errno == EAGAIN || errno == EINTR))
1369: ;
1.14 markus 1370: packet_write_poll();
1371: }
1.56 millert 1372: xfree(setp);
1.1 deraadt 1373: }
1374:
1375: /* Returns true if there is buffered data to write to the connection. */
1376:
1.2 provos 1377: int
1.73 itojun 1378: packet_have_data_to_write(void)
1.1 deraadt 1379: {
1.14 markus 1380: return buffer_len(&output) != 0;
1.1 deraadt 1381: }
1382:
1383: /* Returns true if there is not too much data to write to the connection. */
1384:
1.2 provos 1385: int
1.73 itojun 1386: packet_not_very_much_data_to_write(void)
1.1 deraadt 1387: {
1.14 markus 1388: if (interactive_mode)
1389: return buffer_len(&output) < 16384;
1390: else
1391: return buffer_len(&output) < 128 * 1024;
1.1 deraadt 1392: }
1393:
1.102 markus 1394: static void
1.101 markus 1395: packet_set_tos(int interactive)
1396: {
1397: int tos = interactive ? IPTOS_LOWDELAY : IPTOS_THROUGHPUT;
1398:
1399: if (!packet_connection_is_on_socket() ||
1400: !packet_connection_is_ipv4())
1401: return;
1402: if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, &tos,
1403: sizeof(tos)) < 0)
1404: error("setsockopt IP_TOS %d: %.100s:",
1405: tos, strerror(errno));
1406: }
1407:
1.1 deraadt 1408: /* Informs that the current session is interactive. Sets IP flags for that. */
1409:
1.2 provos 1410: void
1.43 markus 1411: packet_set_interactive(int interactive)
1.1 deraadt 1412: {
1.43 markus 1413: static int called = 0;
1.44 markus 1414:
1.43 markus 1415: if (called)
1416: return;
1417: called = 1;
1.1 deraadt 1418:
1.14 markus 1419: /* Record that we are in interactive mode. */
1420: interactive_mode = interactive;
1.1 deraadt 1421:
1.19 markus 1422: /* Only set socket options if using a socket. */
1423: if (!packet_connection_is_on_socket())
1.14 markus 1424: return;
1.101 markus 1425: if (interactive)
1.86 stevesk 1426: set_nodelay(connection_in);
1.101 markus 1427: packet_set_tos(interactive);
1.1 deraadt 1428: }
1429:
1430: /* Returns true if the current connection is interactive. */
1431:
1.2 provos 1432: int
1.73 itojun 1433: packet_is_interactive(void)
1.1 deraadt 1434: {
1.14 markus 1435: return interactive_mode;
1.12 markus 1436: }
1437:
1438: int
1439: packet_set_maxsize(int s)
1440: {
1.14 markus 1441: static int called = 0;
1.97 deraadt 1442:
1.14 markus 1443: if (called) {
1.25 markus 1444: log("packet_set_maxsize: called twice: old %d new %d",
1445: max_packet_size, s);
1.14 markus 1446: return -1;
1447: }
1448: if (s < 4 * 1024 || s > 1024 * 1024) {
1449: log("packet_set_maxsize: bad size %d", s);
1450: return -1;
1451: }
1.70 markus 1452: called = 1;
1.66 markus 1453: debug("packet_set_maxsize: setting to %d", s);
1.14 markus 1454: max_packet_size = s;
1455: return s;
1.53 markus 1456: }
1457:
1.71 markus 1458: /* roundup current message to pad bytes */
1459: void
1460: packet_add_padding(u_char pad)
1461: {
1462: extra_pad = pad;
1463: }
1464:
1.53 markus 1465: /*
1466: * 9.2. Ignored Data Message
1.61 markus 1467: *
1.53 markus 1468: * byte SSH_MSG_IGNORE
1469: * string data
1.61 markus 1470: *
1.53 markus 1471: * All implementations MUST understand (and ignore) this message at any
1472: * time (after receiving the protocol version). No implementation is
1473: * required to send them. This message can be used as an additional
1474: * protection measure against advanced traffic analysis techniques.
1475: */
1.54 markus 1476: void
1477: packet_send_ignore(int nbytes)
1478: {
1479: u_int32_t rand = 0;
1480: int i;
1481:
1482: packet_start(compat20 ? SSH2_MSG_IGNORE : SSH_MSG_IGNORE);
1.53 markus 1483: packet_put_int(nbytes);
1.75 deraadt 1484: for (i = 0; i < nbytes; i++) {
1.53 markus 1485: if (i % 4 == 0)
1486: rand = arc4random();
1487: packet_put_char(rand & 0xff);
1488: rand >>= 8;
1489: }
1.105 ! markus 1490: }
! 1491:
! 1492: #define MAX_PACKETS (1<<31)
! 1493: int
! 1494: packet_need_rekeying(void)
! 1495: {
! 1496: if (datafellows & SSH_BUG_NOREKEY)
! 1497: return 0;
! 1498: return
! 1499: (p_send.packets > MAX_PACKETS) ||
! 1500: (p_read.packets > MAX_PACKETS) ||
! 1501: (max_blocks_out && (p_send.blocks > max_blocks_out)) ||
! 1502: (max_blocks_in && (p_read.blocks > max_blocks_in));
! 1503: }
! 1504:
! 1505: void
! 1506: packet_set_rekey_limit(u_int32_t bytes)
! 1507: {
! 1508: rekey_limit = bytes;
1.1 deraadt 1509: }
![[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