Annotation of src/usr.bin/ssh/packet.c, Revision 1.110
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"
1.110 ! markus 40: RCSID("$OpenBSD: packet.c,v 1.109 2003/07/10 14:42:28 markus Exp $");
1.105 markus 41:
42: #include <sys/queue.h>
1.1 deraadt 43:
44: #include "xmalloc.h"
45: #include "buffer.h"
46: #include "packet.h"
47: #include "bufaux.h"
48: #include "crc32.h"
49: #include "getput.h"
50:
51: #include "compress.h"
1.9 dugsong 52: #include "deattack.h"
1.64 markus 53: #include "channels.h"
1.1 deraadt 54:
1.25 markus 55: #include "compat.h"
1.45 markus 56: #include "ssh1.h"
1.25 markus 57: #include "ssh2.h"
58:
1.37 markus 59: #include "cipher.h"
1.25 markus 60: #include "kex.h"
1.50 markus 61: #include "mac.h"
1.46 markus 62: #include "log.h"
63: #include "canohost.h"
1.87 stevesk 64: #include "misc.h"
1.95 markus 65: #include "ssh.h"
1.25 markus 66:
67: #ifdef PACKET_DEBUG
68: #define DBG(x) x
69: #else
70: #define DBG(x)
71: #endif
72:
1.16 markus 73: /*
74: * This variable contains the file descriptors used for communicating with
75: * the other side. connection_in is used for reading; connection_out for
76: * writing. These can be the same descriptor, in which case it is assumed to
77: * be a socket.
78: */
1.1 deraadt 79: static int connection_in = -1;
80: static int connection_out = -1;
81:
82: /* Protocol flags for the remote side. */
1.40 markus 83: static u_int remote_protocol_flags = 0;
1.1 deraadt 84:
85: /* Encryption context for receiving data. This is only used for decryption. */
86: static CipherContext receive_context;
1.14 markus 87:
88: /* Encryption context for sending data. This is only used for encryption. */
1.1 deraadt 89: static CipherContext send_context;
90:
91: /* Buffer for raw input data from the socket. */
1.91 markus 92: Buffer input;
1.1 deraadt 93:
94: /* Buffer for raw output data going to the socket. */
1.91 markus 95: Buffer output;
1.1 deraadt 96:
97: /* Buffer for the partial outgoing packet being constructed. */
98: static Buffer outgoing_packet;
99:
100: /* Buffer for the incoming packet currently being processed. */
101: static Buffer incoming_packet;
102:
103: /* Scratch buffer for packet compression/decompression. */
104: static Buffer compression_buffer;
1.60 markus 105: static int compression_buffer_ready = 0;
1.1 deraadt 106:
107: /* Flag indicating whether packet compression/decompression is enabled. */
108: static int packet_compression = 0;
109:
1.12 markus 110: /* default maximum packet size */
1.108 markus 111: u_int max_packet_size = 32768;
1.12 markus 112:
1.1 deraadt 113: /* Flag indicating whether this module has been initialized. */
114: static int initialized = 0;
115:
116: /* Set to true if the connection is interactive. */
117: static int interactive_mode = 0;
118:
1.25 markus 119: /* Session key information for Encryption and MAC */
1.57 markus 120: Newkeys *newkeys[MODE_MAX];
1.105 markus 121: static struct packet_state {
122: u_int32_t seqnr;
123: u_int32_t packets;
124: u_int64_t blocks;
125: } p_read, p_send;
126:
127: static u_int64_t max_blocks_in, max_blocks_out;
128: static u_int32_t rekey_limit;
1.25 markus 129:
1.95 markus 130: /* Session key for protocol v1 */
131: static u_char ssh1_key[SSH_SESSION_KEY_LENGTH];
132: static u_int ssh1_keylen;
133:
1.71 markus 134: /* roundup current message to extra_pad bytes */
135: static u_char extra_pad = 0;
136:
1.105 markus 137: struct packet {
138: TAILQ_ENTRY(packet) next;
139: u_char type;
140: Buffer payload;
141: };
142: TAILQ_HEAD(, packet) outgoing;
143:
1.16 markus 144: /*
145: * Sets the descriptors used for communication. Disables encryption until
146: * packet_set_encryption_key is called.
147: */
1.2 provos 148: void
149: packet_set_connection(int fd_in, int fd_out)
1.1 deraadt 150: {
1.37 markus 151: Cipher *none = cipher_by_name("none");
1.97 deraadt 152:
1.37 markus 153: if (none == NULL)
154: fatal("packet_set_connection: cannot load cipher 'none'");
1.14 markus 155: connection_in = fd_in;
156: connection_out = fd_out;
1.88 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
1.107 deraadt 268: packet_get_ssh1_cipher(void)
1.91 markus 269: {
270: return (cipher_get_number(receive_context.cipher));
271: }
272:
1.105 markus 273: void
274: packet_get_state(int mode, u_int32_t *seqnr, u_int64_t *blocks, u_int32_t *packets)
275: {
276: struct packet_state *state;
1.104 markus 277:
1.105 markus 278: state = (mode == MODE_IN) ? &p_read : &p_send;
279: *seqnr = state->seqnr;
280: *blocks = state->blocks;
281: *packets = state->packets;
1.91 markus 282: }
283:
284: void
1.105 markus 285: packet_set_state(int mode, u_int32_t seqnr, u_int64_t blocks, u_int32_t packets)
1.91 markus 286: {
1.105 markus 287: struct packet_state *state;
288:
289: state = (mode == MODE_IN) ? &p_read : &p_send;
290: state->seqnr = seqnr;
291: state->blocks = blocks;
292: state->packets = packets;
1.91 markus 293: }
294:
1.19 markus 295: /* returns 1 if connection is via ipv4 */
296:
297: int
1.73 itojun 298: packet_connection_is_ipv4(void)
1.19 markus 299: {
300: struct sockaddr_storage to;
1.21 deraadt 301: socklen_t tolen = sizeof(to);
1.19 markus 302:
303: memset(&to, 0, sizeof(to));
304: if (getsockname(connection_out, (struct sockaddr *)&to, &tolen) < 0)
305: return 0;
306: if (to.ss_family != AF_INET)
307: return 0;
308: return 1;
309: }
310:
1.1 deraadt 311: /* Sets the connection into non-blocking mode. */
312:
1.2 provos 313: void
1.73 itojun 314: packet_set_nonblocking(void)
1.1 deraadt 315: {
1.14 markus 316: /* Set the socket into non-blocking mode. */
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: }
1.109 markus 633: /*
634: * The 2^(blocksize*2) limit is too expensive for 3DES,
635: * blowfish, etc, so enforce a 1GB limit for small blocksizes.
636: */
637: if (enc->block_size >= 16)
638: *max_blocks = (u_int64_t)1 << (enc->block_size*2);
639: else
640: *max_blocks = ((u_int64_t)1 << 30) / enc->block_size;
1.105 markus 641: if (rekey_limit)
642: *max_blocks = MIN(*max_blocks, rekey_limit / enc->block_size);
1.57 markus 643: }
644:
1.16 markus 645: /*
1.25 markus 646: * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue)
647: */
1.68 itojun 648: static void
1.105 markus 649: packet_send2_wrapped(void)
1.25 markus 650: {
1.89 markus 651: u_char type, *cp, *macbuf = NULL;
1.71 markus 652: u_char padlen, pad;
1.40 markus 653: u_int packet_length = 0;
1.71 markus 654: u_int i, len;
1.25 markus 655: u_int32_t rand = 0;
656: Enc *enc = NULL;
657: Mac *mac = NULL;
658: Comp *comp = NULL;
659: int block_size;
660:
1.57 markus 661: if (newkeys[MODE_OUT] != NULL) {
662: enc = &newkeys[MODE_OUT]->enc;
663: mac = &newkeys[MODE_OUT]->mac;
664: comp = &newkeys[MODE_OUT]->comp;
1.25 markus 665: }
1.88 markus 666: block_size = enc ? enc->block_size : 8;
1.25 markus 667:
1.89 markus 668: cp = buffer_ptr(&outgoing_packet);
669: type = cp[5];
1.25 markus 670:
671: #ifdef PACKET_DEBUG
672: fprintf(stderr, "plain: ");
673: buffer_dump(&outgoing_packet);
674: #endif
675:
676: if (comp && comp->enabled) {
677: len = buffer_len(&outgoing_packet);
678: /* skip header, compress only payload */
679: buffer_consume(&outgoing_packet, 5);
680: buffer_clear(&compression_buffer);
681: buffer_compress(&outgoing_packet, &compression_buffer);
682: buffer_clear(&outgoing_packet);
683: buffer_append(&outgoing_packet, "\0\0\0\0\0", 5);
684: buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer),
685: buffer_len(&compression_buffer));
686: DBG(debug("compression: raw %d compressed %d", len,
687: buffer_len(&outgoing_packet)));
688: }
689:
690: /* sizeof (packet_len + pad_len + payload) */
691: len = buffer_len(&outgoing_packet);
692:
693: /*
694: * calc size of padding, alloc space, get random data,
695: * minimum padding is 4 bytes
696: */
697: padlen = block_size - (len % block_size);
698: if (padlen < 4)
699: padlen += block_size;
1.71 markus 700: if (extra_pad) {
701: /* will wrap if extra_pad+padlen > 255 */
702: extra_pad = roundup(extra_pad, block_size);
703: pad = extra_pad - ((len + padlen) % extra_pad);
1.93 markus 704: debug3("packet_send2: adding %d (len %d padlen %d extra_pad %d)",
1.71 markus 705: pad, len, padlen, extra_pad);
706: padlen += pad;
707: extra_pad = 0;
708: }
1.76 stevesk 709: cp = buffer_append_space(&outgoing_packet, padlen);
1.88 markus 710: if (enc && !send_context.plaintext) {
1.32 markus 711: /* random padding */
1.25 markus 712: for (i = 0; i < padlen; i++) {
713: if (i % 4 == 0)
714: rand = arc4random();
715: cp[i] = rand & 0xff;
1.52 markus 716: rand >>= 8;
1.25 markus 717: }
1.32 markus 718: } else {
719: /* clear padding */
720: memset(cp, 0, padlen);
1.25 markus 721: }
722: /* packet_length includes payload, padding and padding length field */
723: packet_length = buffer_len(&outgoing_packet) - 4;
1.89 markus 724: cp = buffer_ptr(&outgoing_packet);
725: PUT_32BIT(cp, packet_length);
726: cp[4] = padlen;
1.25 markus 727: DBG(debug("send: len %d (includes padlen %d)", packet_length+4, padlen));
728:
729: /* compute MAC over seqnr and packet(length fields, payload, padding) */
730: if (mac && mac->enabled) {
1.105 markus 731: macbuf = mac_compute(mac, p_send.seqnr,
1.83 stevesk 732: buffer_ptr(&outgoing_packet),
1.50 markus 733: buffer_len(&outgoing_packet));
1.105 markus 734: DBG(debug("done calc MAC out #%d", p_send.seqnr));
1.25 markus 735: }
736: /* encrypt packet and append to output buffer. */
1.76 stevesk 737: cp = buffer_append_space(&output, buffer_len(&outgoing_packet));
1.88 markus 738: cipher_crypt(&send_context, cp, buffer_ptr(&outgoing_packet),
1.25 markus 739: buffer_len(&outgoing_packet));
740: /* append unencrypted MAC */
741: if (mac && mac->enabled)
742: buffer_append(&output, (char *)macbuf, mac->mac_len);
743: #ifdef PACKET_DEBUG
744: fprintf(stderr, "encrypted: ");
745: buffer_dump(&output);
746: #endif
1.29 markus 747: /* increment sequence number for outgoing packets */
1.105 markus 748: if (++p_send.seqnr == 0)
1.106 itojun 749: logit("outgoing seqnr wraps around");
1.105 markus 750: if (++p_send.packets == 0)
751: if (!(datafellows & SSH_BUG_NOREKEY))
752: fatal("XXX too many packets with same key");
753: p_send.blocks += (packet_length + 4) / block_size;
1.25 markus 754: buffer_clear(&outgoing_packet);
755:
1.57 markus 756: if (type == SSH2_MSG_NEWKEYS)
757: set_newkeys(MODE_OUT);
1.25 markus 758: }
759:
1.105 markus 760: static void
761: packet_send2(void)
762: {
763: static int rekeying = 0;
764: struct packet *p;
765: u_char type, *cp;
766:
767: cp = buffer_ptr(&outgoing_packet);
768: type = cp[5];
769:
770: /* during rekeying we can only send key exchange messages */
771: if (rekeying) {
772: if (!((type >= SSH2_MSG_TRANSPORT_MIN) &&
773: (type <= SSH2_MSG_TRANSPORT_MAX))) {
774: debug("enqueue packet: %u", type);
775: p = xmalloc(sizeof(*p));
776: p->type = type;
777: memcpy(&p->payload, &outgoing_packet, sizeof(Buffer));
778: buffer_init(&outgoing_packet);
779: TAILQ_INSERT_TAIL(&outgoing, p, next);
780: return;
781: }
782: }
783:
784: /* rekeying starts with sending KEXINIT */
785: if (type == SSH2_MSG_KEXINIT)
786: rekeying = 1;
787:
788: packet_send2_wrapped();
789:
790: /* after a NEWKEYS message we can send the complete queue */
791: if (type == SSH2_MSG_NEWKEYS) {
792: rekeying = 0;
793: while ((p = TAILQ_FIRST(&outgoing))) {
794: type = p->type;
795: debug("dequeue packet: %u", type);
796: buffer_free(&outgoing_packet);
797: memcpy(&outgoing_packet, &p->payload,
798: sizeof(Buffer));
799: TAILQ_REMOVE(&outgoing, p, next);
800: xfree(p);
801: packet_send2_wrapped();
802: }
803: }
804: }
805:
1.25 markus 806: void
1.73 itojun 807: packet_send(void)
1.25 markus 808: {
1.62 markus 809: if (compat20)
1.25 markus 810: packet_send2();
811: else
812: packet_send1();
813: DBG(debug("packet_send done"));
814: }
815:
816: /*
1.16 markus 817: * Waits until a packet has been received, and returns its type. Note that
818: * no other data is processed until this returns, so this function should not
819: * be used during the interactive session.
820: */
1.1 deraadt 821:
1.2 provos 822: int
1.82 markus 823: packet_read_seqnr(u_int32_t *seqnr_p)
1.1 deraadt 824: {
1.14 markus 825: int type, len;
1.56 millert 826: fd_set *setp;
1.14 markus 827: char buf[8192];
1.25 markus 828: DBG(debug("packet_read()"));
1.14 markus 829:
1.56 millert 830: setp = (fd_set *)xmalloc(howmany(connection_in+1, NFDBITS) *
831: sizeof(fd_mask));
832:
1.14 markus 833: /* Since we are blocking, ensure that all written packets have been sent. */
834: packet_write_wait();
835:
836: /* Stay in the loop until we have received a complete packet. */
837: for (;;) {
838: /* Try to read a packet from the buffer. */
1.82 markus 839: type = packet_read_poll_seqnr(seqnr_p);
1.62 markus 840: if (!compat20 && (
1.32 markus 841: type == SSH_SMSG_SUCCESS
1.14 markus 842: || type == SSH_SMSG_FAILURE
843: || type == SSH_CMSG_EOF
1.32 markus 844: || type == SSH_CMSG_EXIT_CONFIRMATION))
1.79 markus 845: packet_check_eom();
1.14 markus 846: /* If we got a packet, return it. */
1.56 millert 847: if (type != SSH_MSG_NONE) {
848: xfree(setp);
1.14 markus 849: return type;
1.56 millert 850: }
1.16 markus 851: /*
852: * Otherwise, wait for some data to arrive, add it to the
853: * buffer, and try again.
854: */
1.56 millert 855: memset(setp, 0, howmany(connection_in + 1, NFDBITS) *
856: sizeof(fd_mask));
857: FD_SET(connection_in, setp);
1.16 markus 858:
1.14 markus 859: /* Wait for some data to arrive. */
1.56 millert 860: while (select(connection_in + 1, setp, NULL, NULL, NULL) == -1 &&
1.51 deraadt 861: (errno == EAGAIN || errno == EINTR))
862: ;
1.16 markus 863:
1.14 markus 864: /* Read data from the socket. */
865: len = read(connection_in, buf, sizeof(buf));
1.18 markus 866: if (len == 0) {
1.106 itojun 867: logit("Connection closed by %.200s", get_remote_ipaddr());
1.18 markus 868: fatal_cleanup();
869: }
1.14 markus 870: if (len < 0)
871: fatal("Read from socket failed: %.100s", strerror(errno));
872: /* Append it to the buffer. */
873: packet_process_incoming(buf, len);
874: }
875: /* NOTREACHED */
1.1 deraadt 876: }
877:
1.77 djm 878: int
1.82 markus 879: packet_read(void)
1.77 djm 880: {
1.82 markus 881: return packet_read_seqnr(NULL);
1.77 djm 882: }
883:
1.16 markus 884: /*
885: * Waits until a packet has been received, verifies that its type matches
886: * that given, and gives a fatal error and exits if there is a mismatch.
887: */
1.1 deraadt 888:
1.2 provos 889: void
1.82 markus 890: packet_read_expect(int expected_type)
1.1 deraadt 891: {
1.14 markus 892: int type;
1.1 deraadt 893:
1.82 markus 894: type = packet_read();
1.14 markus 895: if (type != expected_type)
896: packet_disconnect("Protocol error: expected packet type %d, got %d",
1.25 markus 897: expected_type, type);
1.1 deraadt 898: }
899:
900: /* Checks if a full packet is available in the data received so far via
1.14 markus 901: * packet_process_incoming. If so, reads the packet; otherwise returns
902: * SSH_MSG_NONE. This does not wait for data from the connection.
903: *
904: * SSH_MSG_DISCONNECT is handled specially here. Also,
905: * SSH_MSG_IGNORE messages are skipped by this function and are never returned
906: * to higher levels.
907: */
1.1 deraadt 908:
1.68 itojun 909: static int
1.82 markus 910: packet_read_poll1(void)
1.1 deraadt 911: {
1.40 markus 912: u_int len, padded_len;
1.89 markus 913: u_char *cp, type;
1.40 markus 914: u_int checksum, stored_checksum;
1.14 markus 915:
916: /* Check if input size is less than minimum packet size. */
917: if (buffer_len(&input) < 4 + 8)
918: return SSH_MSG_NONE;
919: /* Get length of incoming packet. */
1.89 markus 920: cp = buffer_ptr(&input);
921: len = GET_32BIT(cp);
1.14 markus 922: if (len < 1 + 2 + 2 || len > 256 * 1024)
1.98 markus 923: packet_disconnect("Bad packet length %u.", len);
1.14 markus 924: padded_len = (len + 8) & ~7;
925:
926: /* Check if the packet has been entirely received. */
927: if (buffer_len(&input) < 4 + padded_len)
928: return SSH_MSG_NONE;
929:
930: /* The entire packet is in buffer. */
931:
932: /* Consume packet length. */
933: buffer_consume(&input, 4);
934:
1.62 markus 935: /*
936: * Cryptographic attack detector for ssh
937: * (C)1998 CORE-SDI, Buenos Aires Argentina
938: * Ariel Futoransky(futo@core-sdi.com)
939: */
1.88 markus 940: if (!receive_context.plaintext &&
1.62 markus 941: detect_attack(buffer_ptr(&input), padded_len, NULL) == DEATTACK_DETECTED)
942: packet_disconnect("crc32 compensation attack: network attack detected");
943:
944: /* Decrypt data to incoming_packet. */
1.14 markus 945: buffer_clear(&incoming_packet);
1.76 stevesk 946: cp = buffer_append_space(&incoming_packet, padded_len);
1.88 markus 947: cipher_crypt(&receive_context, cp, buffer_ptr(&input), padded_len);
1.62 markus 948:
1.14 markus 949: buffer_consume(&input, padded_len);
1.1 deraadt 950:
951: #ifdef PACKET_DEBUG
1.14 markus 952: fprintf(stderr, "read_poll plain: ");
953: buffer_dump(&incoming_packet);
1.1 deraadt 954: #endif
955:
1.14 markus 956: /* Compute packet checksum. */
1.83 stevesk 957: checksum = ssh_crc32(buffer_ptr(&incoming_packet),
1.25 markus 958: buffer_len(&incoming_packet) - 4);
1.14 markus 959:
960: /* Skip padding. */
961: buffer_consume(&incoming_packet, 8 - len % 8);
962:
963: /* Test check bytes. */
964: if (len != buffer_len(&incoming_packet))
1.77 djm 965: packet_disconnect("packet_read_poll1: len %d != buffer_len %d.",
1.25 markus 966: len, buffer_len(&incoming_packet));
1.14 markus 967:
1.89 markus 968: cp = (u_char *)buffer_ptr(&incoming_packet) + len - 4;
969: stored_checksum = GET_32BIT(cp);
1.14 markus 970: if (checksum != stored_checksum)
971: packet_disconnect("Corrupted check bytes on input.");
972: buffer_consume_end(&incoming_packet, 4);
973:
974: if (packet_compression) {
975: buffer_clear(&compression_buffer);
976: buffer_uncompress(&incoming_packet, &compression_buffer);
977: buffer_clear(&incoming_packet);
978: buffer_append(&incoming_packet, buffer_ptr(&compression_buffer),
1.25 markus 979: buffer_len(&compression_buffer));
1.14 markus 980: }
1.62 markus 981: type = buffer_get_char(&incoming_packet);
982: return type;
1.1 deraadt 983: }
1.14 markus 984:
1.68 itojun 985: static int
1.82 markus 986: packet_read_poll2(u_int32_t *seqnr_p)
1.25 markus 987: {
1.50 markus 988: static u_int packet_length = 0;
1.40 markus 989: u_int padlen, need;
1.89 markus 990: u_char *macbuf, *cp, type;
1.25 markus 991: int maclen, block_size;
992: Enc *enc = NULL;
993: Mac *mac = NULL;
994: Comp *comp = NULL;
995:
1.57 markus 996: if (newkeys[MODE_IN] != NULL) {
997: enc = &newkeys[MODE_IN]->enc;
998: mac = &newkeys[MODE_IN]->mac;
999: comp = &newkeys[MODE_IN]->comp;
1.25 markus 1000: }
1001: maclen = mac && mac->enabled ? mac->mac_len : 0;
1.88 markus 1002: block_size = enc ? enc->block_size : 8;
1.25 markus 1003:
1004: if (packet_length == 0) {
1005: /*
1006: * check if input size is less than the cipher block size,
1007: * decrypt first block and extract length of incoming packet
1008: */
1009: if (buffer_len(&input) < block_size)
1010: return SSH_MSG_NONE;
1011: buffer_clear(&incoming_packet);
1.76 stevesk 1012: cp = buffer_append_space(&incoming_packet, block_size);
1.88 markus 1013: cipher_crypt(&receive_context, cp, buffer_ptr(&input),
1.25 markus 1014: block_size);
1.89 markus 1015: cp = buffer_ptr(&incoming_packet);
1016: packet_length = GET_32BIT(cp);
1.25 markus 1017: if (packet_length < 1 + 4 || packet_length > 256 * 1024) {
1.110 ! markus 1018: #ifdef PACKET_DEBUG
1.25 markus 1019: buffer_dump(&incoming_packet);
1.110 ! markus 1020: #endif
1.98 markus 1021: packet_disconnect("Bad packet length %u.", packet_length);
1.25 markus 1022: }
1.98 markus 1023: DBG(debug("input: packet len %u", packet_length+4));
1.25 markus 1024: buffer_consume(&input, block_size);
1025: }
1026: /* we have a partial packet of block_size bytes */
1027: need = 4 + packet_length - block_size;
1028: DBG(debug("partial packet %d, need %d, maclen %d", block_size,
1029: need, maclen));
1030: if (need % block_size != 0)
1031: fatal("padding error: need %d block %d mod %d",
1032: need, block_size, need % block_size);
1033: /*
1034: * check if the entire packet has been received and
1035: * decrypt into incoming_packet
1036: */
1037: if (buffer_len(&input) < need + maclen)
1038: return SSH_MSG_NONE;
1039: #ifdef PACKET_DEBUG
1040: fprintf(stderr, "read_poll enc/full: ");
1041: buffer_dump(&input);
1042: #endif
1.76 stevesk 1043: cp = buffer_append_space(&incoming_packet, need);
1.88 markus 1044: cipher_crypt(&receive_context, cp, buffer_ptr(&input), need);
1.25 markus 1045: buffer_consume(&input, need);
1046: /*
1047: * compute MAC over seqnr and packet,
1048: * increment sequence number for incoming packet
1049: */
1.29 markus 1050: if (mac && mac->enabled) {
1.105 markus 1051: macbuf = mac_compute(mac, p_read.seqnr,
1.83 stevesk 1052: buffer_ptr(&incoming_packet),
1.50 markus 1053: buffer_len(&incoming_packet));
1.25 markus 1054: if (memcmp(macbuf, buffer_ptr(&input), mac->mac_len) != 0)
1.36 markus 1055: packet_disconnect("Corrupted MAC on input.");
1.105 markus 1056: DBG(debug("MAC #%d ok", p_read.seqnr));
1.25 markus 1057: buffer_consume(&input, mac->mac_len);
1058: }
1.77 djm 1059: if (seqnr_p != NULL)
1.105 markus 1060: *seqnr_p = p_read.seqnr;
1061: if (++p_read.seqnr == 0)
1.106 itojun 1062: logit("incoming seqnr wraps around");
1.105 markus 1063: if (++p_read.packets == 0)
1064: if (!(datafellows & SSH_BUG_NOREKEY))
1065: fatal("XXX too many packets with same key");
1066: p_read.blocks += (packet_length + 4) / block_size;
1.25 markus 1067:
1068: /* get padlen */
1.76 stevesk 1069: cp = buffer_ptr(&incoming_packet);
1.89 markus 1070: padlen = cp[4];
1.25 markus 1071: DBG(debug("input: padlen %d", padlen));
1072: if (padlen < 4)
1073: packet_disconnect("Corrupted padlen %d on input.", padlen);
1074:
1075: /* skip packet size + padlen, discard padding */
1076: buffer_consume(&incoming_packet, 4 + 1);
1077: buffer_consume_end(&incoming_packet, padlen);
1078:
1079: DBG(debug("input: len before de-compress %d", buffer_len(&incoming_packet)));
1080: if (comp && comp->enabled) {
1081: buffer_clear(&compression_buffer);
1082: buffer_uncompress(&incoming_packet, &compression_buffer);
1083: buffer_clear(&incoming_packet);
1084: buffer_append(&incoming_packet, buffer_ptr(&compression_buffer),
1085: buffer_len(&compression_buffer));
1.97 deraadt 1086: DBG(debug("input: len after de-compress %d",
1087: buffer_len(&incoming_packet)));
1.25 markus 1088: }
1089: /*
1090: * get packet type, implies consume.
1091: * return length of payload (without type field)
1092: */
1.62 markus 1093: type = buffer_get_char(&incoming_packet);
1.57 markus 1094: if (type == SSH2_MSG_NEWKEYS)
1095: set_newkeys(MODE_IN);
1.25 markus 1096: #ifdef PACKET_DEBUG
1.55 deraadt 1097: fprintf(stderr, "read/plain[%d]:\r\n", type);
1.25 markus 1098: buffer_dump(&incoming_packet);
1099: #endif
1.62 markus 1100: /* reset for next packet */
1101: packet_length = 0;
1102: return type;
1.25 markus 1103: }
1104:
1105: int
1.82 markus 1106: packet_read_poll_seqnr(u_int32_t *seqnr_p)
1.25 markus 1107: {
1.96 deraadt 1108: u_int reason, seqnr;
1.62 markus 1109: u_char type;
1.25 markus 1110: char *msg;
1.62 markus 1111:
1.25 markus 1112: for (;;) {
1.62 markus 1113: if (compat20) {
1.82 markus 1114: type = packet_read_poll2(seqnr_p);
1.62 markus 1115: if (type)
1.25 markus 1116: DBG(debug("received packet type %d", type));
1.74 deraadt 1117: switch (type) {
1.25 markus 1118: case SSH2_MSG_IGNORE:
1119: break;
1120: case SSH2_MSG_DEBUG:
1121: packet_get_char();
1122: msg = packet_get_string(NULL);
1123: debug("Remote: %.900s", msg);
1124: xfree(msg);
1125: msg = packet_get_string(NULL);
1126: xfree(msg);
1127: break;
1128: case SSH2_MSG_DISCONNECT:
1129: reason = packet_get_int();
1130: msg = packet_get_string(NULL);
1.106 itojun 1131: logit("Received disconnect from %s: %u: %.400s",
1.96 deraadt 1132: get_remote_ipaddr(), reason, msg);
1.25 markus 1133: xfree(msg);
1134: fatal_cleanup();
1.84 markus 1135: break;
1136: case SSH2_MSG_UNIMPLEMENTED:
1137: seqnr = packet_get_int();
1.96 deraadt 1138: debug("Received SSH2_MSG_UNIMPLEMENTED for %u",
1139: seqnr);
1.25 markus 1140: break;
1141: default:
1142: return type;
1143: break;
1.48 stevesk 1144: }
1.25 markus 1145: } else {
1.82 markus 1146: type = packet_read_poll1();
1.74 deraadt 1147: switch (type) {
1.25 markus 1148: case SSH_MSG_IGNORE:
1149: break;
1150: case SSH_MSG_DEBUG:
1151: msg = packet_get_string(NULL);
1152: debug("Remote: %.900s", msg);
1153: xfree(msg);
1154: break;
1155: case SSH_MSG_DISCONNECT:
1156: msg = packet_get_string(NULL);
1.106 itojun 1157: logit("Received disconnect from %s: %.400s",
1.96 deraadt 1158: get_remote_ipaddr(), msg);
1.25 markus 1159: fatal_cleanup();
1160: xfree(msg);
1161: break;
1162: default:
1.62 markus 1163: if (type)
1.25 markus 1164: DBG(debug("received packet type %d", type));
1165: return type;
1166: break;
1.48 stevesk 1167: }
1.25 markus 1168: }
1169: }
1.77 djm 1170: }
1171:
1172: int
1.82 markus 1173: packet_read_poll(void)
1.77 djm 1174: {
1.82 markus 1175: return packet_read_poll_seqnr(NULL);
1.25 markus 1176: }
1177:
1.16 markus 1178: /*
1179: * Buffers the given amount of input characters. This is intended to be used
1180: * together with packet_read_poll.
1181: */
1.1 deraadt 1182:
1.2 provos 1183: void
1.40 markus 1184: packet_process_incoming(const char *buf, u_int len)
1.1 deraadt 1185: {
1.14 markus 1186: buffer_append(&input, buf, len);
1.1 deraadt 1187: }
1188:
1189: /* Returns a character from the packet. */
1190:
1.40 markus 1191: u_int
1.73 itojun 1192: packet_get_char(void)
1.1 deraadt 1193: {
1.14 markus 1194: char ch;
1.97 deraadt 1195:
1.14 markus 1196: buffer_get(&incoming_packet, &ch, 1);
1.40 markus 1197: return (u_char) ch;
1.1 deraadt 1198: }
1199:
1200: /* Returns an integer from the packet data. */
1201:
1.40 markus 1202: u_int
1.73 itojun 1203: packet_get_int(void)
1.1 deraadt 1204: {
1.14 markus 1205: return buffer_get_int(&incoming_packet);
1.1 deraadt 1206: }
1207:
1.16 markus 1208: /*
1209: * Returns an arbitrary precision integer from the packet data. The integer
1210: * must have been initialized before this call.
1211: */
1.1 deraadt 1212:
1.2 provos 1213: void
1.80 markus 1214: packet_get_bignum(BIGNUM * value)
1.1 deraadt 1215: {
1.81 markus 1216: buffer_get_bignum(&incoming_packet, value);
1.24 markus 1217: }
1218:
1219: void
1.80 markus 1220: packet_get_bignum2(BIGNUM * value)
1.24 markus 1221: {
1.81 markus 1222: buffer_get_bignum2(&incoming_packet, value);
1.24 markus 1223: }
1224:
1.76 stevesk 1225: void *
1.24 markus 1226: packet_get_raw(int *length_ptr)
1227: {
1228: int bytes = buffer_len(&incoming_packet);
1.97 deraadt 1229:
1.24 markus 1230: if (length_ptr != NULL)
1231: *length_ptr = bytes;
1232: return buffer_ptr(&incoming_packet);
1.28 markus 1233: }
1234:
1235: int
1236: packet_remaining(void)
1237: {
1238: return buffer_len(&incoming_packet);
1.1 deraadt 1239: }
1240:
1.16 markus 1241: /*
1242: * Returns a string from the packet data. The string is allocated using
1243: * xmalloc; it is the responsibility of the calling program to free it when
1244: * no longer needed. The length_ptr argument may be NULL, or point to an
1245: * integer into which the length of the string is stored.
1246: */
1.1 deraadt 1247:
1.76 stevesk 1248: void *
1.40 markus 1249: packet_get_string(u_int *length_ptr)
1.1 deraadt 1250: {
1.14 markus 1251: return buffer_get_string(&incoming_packet, length_ptr);
1.1 deraadt 1252: }
1253:
1.16 markus 1254: /*
1255: * Sends a diagnostic message from the server to the client. This message
1256: * can be sent at any time (but not while constructing another message). The
1257: * message is printed immediately, but only if the client is being executed
1258: * in verbose mode. These messages are primarily intended to ease debugging
1259: * authentication problems. The length of the formatted message must not
1260: * exceed 1024 bytes. This will automatically call packet_write_wait.
1261: */
1.1 deraadt 1262:
1.2 provos 1263: void
1.14 markus 1264: packet_send_debug(const char *fmt,...)
1.1 deraadt 1265: {
1.14 markus 1266: char buf[1024];
1267: va_list args;
1.39 markus 1268:
1269: if (compat20 && (datafellows & SSH_BUG_DEBUG))
1270: return;
1.14 markus 1271:
1272: va_start(args, fmt);
1273: vsnprintf(buf, sizeof(buf), fmt, args);
1274: va_end(args);
1275:
1.30 markus 1276: if (compat20) {
1277: packet_start(SSH2_MSG_DEBUG);
1278: packet_put_char(0); /* bool: always display */
1279: packet_put_cstring(buf);
1280: packet_put_cstring("");
1281: } else {
1282: packet_start(SSH_MSG_DEBUG);
1283: packet_put_cstring(buf);
1284: }
1.14 markus 1285: packet_send();
1286: packet_write_wait();
1.1 deraadt 1287: }
1288:
1.16 markus 1289: /*
1290: * Logs the error plus constructs and sends a disconnect packet, closes the
1291: * connection, and exits. This function never returns. The error message
1292: * should not contain a newline. The length of the formatted message must
1293: * not exceed 1024 bytes.
1294: */
1.1 deraadt 1295:
1.2 provos 1296: void
1.14 markus 1297: packet_disconnect(const char *fmt,...)
1.1 deraadt 1298: {
1.14 markus 1299: char buf[1024];
1300: va_list args;
1301: static int disconnecting = 0;
1.97 deraadt 1302:
1.14 markus 1303: if (disconnecting) /* Guard against recursive invocations. */
1304: fatal("packet_disconnect called recursively.");
1305: disconnecting = 1;
1306:
1.16 markus 1307: /*
1308: * Format the message. Note that the caller must make sure the
1309: * message is of limited size.
1310: */
1.14 markus 1311: va_start(args, fmt);
1312: vsnprintf(buf, sizeof(buf), fmt, args);
1313: va_end(args);
1314:
1.99 markus 1315: /* Display the error locally */
1.106 itojun 1316: logit("Disconnecting: %.100s", buf);
1.99 markus 1317:
1.14 markus 1318: /* Send the disconnect message to the other side, and wait for it to get sent. */
1.25 markus 1319: if (compat20) {
1320: packet_start(SSH2_MSG_DISCONNECT);
1321: packet_put_int(SSH2_DISCONNECT_PROTOCOL_ERROR);
1322: packet_put_cstring(buf);
1323: packet_put_cstring("");
1324: } else {
1325: packet_start(SSH_MSG_DISCONNECT);
1.65 markus 1326: packet_put_cstring(buf);
1.25 markus 1327: }
1.14 markus 1328: packet_send();
1329: packet_write_wait();
1330:
1331: /* Stop listening for connections. */
1.67 markus 1332: channel_close_all();
1.14 markus 1333:
1334: /* Close the connection. */
1335: packet_close();
1.1 deraadt 1336:
1.17 markus 1337: fatal_cleanup();
1.1 deraadt 1338: }
1339:
1.16 markus 1340: /* Checks if there is any buffered output, and tries to write some of the output. */
1.1 deraadt 1341:
1.2 provos 1342: void
1.73 itojun 1343: packet_write_poll(void)
1.1 deraadt 1344: {
1.14 markus 1345: int len = buffer_len(&output);
1.97 deraadt 1346:
1.14 markus 1347: if (len > 0) {
1348: len = write(connection_out, buffer_ptr(&output), len);
1349: if (len <= 0) {
1350: if (errno == EAGAIN)
1351: return;
1352: else
1353: fatal("Write failed: %.100s", strerror(errno));
1354: }
1355: buffer_consume(&output, len);
1356: }
1.1 deraadt 1357: }
1358:
1.16 markus 1359: /*
1360: * Calls packet_write_poll repeatedly until all pending output data has been
1361: * written.
1362: */
1.1 deraadt 1363:
1.2 provos 1364: void
1.73 itojun 1365: packet_write_wait(void)
1.1 deraadt 1366: {
1.56 millert 1367: fd_set *setp;
1368:
1369: setp = (fd_set *)xmalloc(howmany(connection_out + 1, NFDBITS) *
1370: sizeof(fd_mask));
1.14 markus 1371: packet_write_poll();
1372: while (packet_have_data_to_write()) {
1.56 millert 1373: memset(setp, 0, howmany(connection_out + 1, NFDBITS) *
1374: sizeof(fd_mask));
1375: FD_SET(connection_out, setp);
1376: while (select(connection_out + 1, NULL, setp, NULL, NULL) == -1 &&
1.51 deraadt 1377: (errno == EAGAIN || errno == EINTR))
1378: ;
1.14 markus 1379: packet_write_poll();
1380: }
1.56 millert 1381: xfree(setp);
1.1 deraadt 1382: }
1383:
1384: /* Returns true if there is buffered data to write to the connection. */
1385:
1.2 provos 1386: int
1.73 itojun 1387: packet_have_data_to_write(void)
1.1 deraadt 1388: {
1.14 markus 1389: return buffer_len(&output) != 0;
1.1 deraadt 1390: }
1391:
1392: /* Returns true if there is not too much data to write to the connection. */
1393:
1.2 provos 1394: int
1.73 itojun 1395: packet_not_very_much_data_to_write(void)
1.1 deraadt 1396: {
1.14 markus 1397: if (interactive_mode)
1398: return buffer_len(&output) < 16384;
1399: else
1400: return buffer_len(&output) < 128 * 1024;
1.1 deraadt 1401: }
1402:
1.102 markus 1403: static void
1.101 markus 1404: packet_set_tos(int interactive)
1405: {
1406: int tos = interactive ? IPTOS_LOWDELAY : IPTOS_THROUGHPUT;
1407:
1408: if (!packet_connection_is_on_socket() ||
1409: !packet_connection_is_ipv4())
1410: return;
1411: if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, &tos,
1412: sizeof(tos)) < 0)
1413: error("setsockopt IP_TOS %d: %.100s:",
1414: tos, strerror(errno));
1415: }
1416:
1.1 deraadt 1417: /* Informs that the current session is interactive. Sets IP flags for that. */
1418:
1.2 provos 1419: void
1.43 markus 1420: packet_set_interactive(int interactive)
1.1 deraadt 1421: {
1.43 markus 1422: static int called = 0;
1.44 markus 1423:
1.43 markus 1424: if (called)
1425: return;
1426: called = 1;
1.1 deraadt 1427:
1.14 markus 1428: /* Record that we are in interactive mode. */
1429: interactive_mode = interactive;
1.1 deraadt 1430:
1.19 markus 1431: /* Only set socket options if using a socket. */
1432: if (!packet_connection_is_on_socket())
1.14 markus 1433: return;
1.101 markus 1434: if (interactive)
1.86 stevesk 1435: set_nodelay(connection_in);
1.101 markus 1436: packet_set_tos(interactive);
1.1 deraadt 1437: }
1438:
1439: /* Returns true if the current connection is interactive. */
1440:
1.2 provos 1441: int
1.73 itojun 1442: packet_is_interactive(void)
1.1 deraadt 1443: {
1.14 markus 1444: return interactive_mode;
1.12 markus 1445: }
1446:
1.108 markus 1447: u_int
1448: packet_set_maxsize(u_int s)
1.12 markus 1449: {
1.14 markus 1450: static int called = 0;
1.97 deraadt 1451:
1.14 markus 1452: if (called) {
1.106 itojun 1453: logit("packet_set_maxsize: called twice: old %d new %d",
1.25 markus 1454: max_packet_size, s);
1.14 markus 1455: return -1;
1456: }
1457: if (s < 4 * 1024 || s > 1024 * 1024) {
1.106 itojun 1458: logit("packet_set_maxsize: bad size %d", s);
1.14 markus 1459: return -1;
1460: }
1.70 markus 1461: called = 1;
1.66 markus 1462: debug("packet_set_maxsize: setting to %d", s);
1.14 markus 1463: max_packet_size = s;
1464: return s;
1.53 markus 1465: }
1466:
1.71 markus 1467: /* roundup current message to pad bytes */
1468: void
1469: packet_add_padding(u_char pad)
1470: {
1471: extra_pad = pad;
1472: }
1473:
1.53 markus 1474: /*
1475: * 9.2. Ignored Data Message
1.61 markus 1476: *
1.53 markus 1477: * byte SSH_MSG_IGNORE
1478: * string data
1.61 markus 1479: *
1.53 markus 1480: * All implementations MUST understand (and ignore) this message at any
1481: * time (after receiving the protocol version). No implementation is
1482: * required to send them. This message can be used as an additional
1483: * protection measure against advanced traffic analysis techniques.
1484: */
1.54 markus 1485: void
1486: packet_send_ignore(int nbytes)
1487: {
1488: u_int32_t rand = 0;
1489: int i;
1490:
1491: packet_start(compat20 ? SSH2_MSG_IGNORE : SSH_MSG_IGNORE);
1.53 markus 1492: packet_put_int(nbytes);
1.75 deraadt 1493: for (i = 0; i < nbytes; i++) {
1.53 markus 1494: if (i % 4 == 0)
1495: rand = arc4random();
1496: packet_put_char(rand & 0xff);
1497: rand >>= 8;
1498: }
1.105 markus 1499: }
1500:
1501: #define MAX_PACKETS (1<<31)
1502: int
1503: packet_need_rekeying(void)
1504: {
1505: if (datafellows & SSH_BUG_NOREKEY)
1506: return 0;
1507: return
1508: (p_send.packets > MAX_PACKETS) ||
1509: (p_read.packets > MAX_PACKETS) ||
1510: (max_blocks_out && (p_send.blocks > max_blocks_out)) ||
1511: (max_blocks_in && (p_read.blocks > max_blocks_in));
1512: }
1513:
1514: void
1515: packet_set_rekey_limit(u_int32_t bytes)
1516: {
1517: rekey_limit = bytes;
1.1 deraadt 1518: }
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