Annotation of src/usr.bin/ssh/packet.c, Revision 1.123
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:
41: #include <sys/queue.h>
1.121 stevesk 42:
43: #include <netinet/in_systm.h>
44: #include <netinet/ip.h>
1.1 deraadt 45:
46: #include "xmalloc.h"
47: #include "buffer.h"
48: #include "packet.h"
49: #include "bufaux.h"
50: #include "crc32.h"
51: #include "getput.h"
52:
53: #include "compress.h"
1.9 dugsong 54: #include "deattack.h"
1.64 markus 55: #include "channels.h"
1.1 deraadt 56:
1.25 markus 57: #include "compat.h"
1.45 markus 58: #include "ssh1.h"
1.25 markus 59: #include "ssh2.h"
60:
1.37 markus 61: #include "cipher.h"
1.25 markus 62: #include "kex.h"
1.50 markus 63: #include "mac.h"
1.46 markus 64: #include "log.h"
65: #include "canohost.h"
1.87 stevesk 66: #include "misc.h"
1.95 markus 67: #include "ssh.h"
1.25 markus 68:
69: #ifdef PACKET_DEBUG
70: #define DBG(x) x
71: #else
72: #define DBG(x)
73: #endif
74:
1.16 markus 75: /*
76: * This variable contains the file descriptors used for communicating with
77: * the other side. connection_in is used for reading; connection_out for
78: * writing. These can be the same descriptor, in which case it is assumed to
79: * be a socket.
80: */
1.1 deraadt 81: static int connection_in = -1;
82: static int connection_out = -1;
83:
84: /* Protocol flags for the remote side. */
1.40 markus 85: static u_int remote_protocol_flags = 0;
1.1 deraadt 86:
87: /* Encryption context for receiving data. This is only used for decryption. */
88: static CipherContext receive_context;
1.14 markus 89:
90: /* Encryption context for sending data. This is only used for encryption. */
1.1 deraadt 91: static CipherContext send_context;
92:
93: /* Buffer for raw input data from the socket. */
1.91 markus 94: Buffer input;
1.1 deraadt 95:
96: /* Buffer for raw output data going to the socket. */
1.91 markus 97: Buffer output;
1.1 deraadt 98:
99: /* Buffer for the partial outgoing packet being constructed. */
100: static Buffer outgoing_packet;
101:
102: /* Buffer for the incoming packet currently being processed. */
103: static Buffer incoming_packet;
104:
105: /* Scratch buffer for packet compression/decompression. */
106: static Buffer compression_buffer;
1.60 markus 107: static int compression_buffer_ready = 0;
1.1 deraadt 108:
109: /* Flag indicating whether packet compression/decompression is enabled. */
110: static int packet_compression = 0;
111:
1.12 markus 112: /* default maximum packet size */
1.108 markus 113: u_int max_packet_size = 32768;
1.12 markus 114:
1.1 deraadt 115: /* Flag indicating whether this module has been initialized. */
116: static int initialized = 0;
117:
118: /* Set to true if the connection is interactive. */
119: static int interactive_mode = 0;
120:
1.118 markus 121: /* Set to true if we are the server side. */
122: static int server_side = 0;
123:
124: /* Set to true if we are authenticated. */
125: static int after_authentication = 0;
126:
1.25 markus 127: /* Session key information for Encryption and MAC */
1.57 markus 128: Newkeys *newkeys[MODE_MAX];
1.105 markus 129: static struct packet_state {
130: u_int32_t seqnr;
131: u_int32_t packets;
132: u_int64_t blocks;
133: } p_read, p_send;
134:
135: static u_int64_t max_blocks_in, max_blocks_out;
136: static u_int32_t rekey_limit;
1.25 markus 137:
1.95 markus 138: /* Session key for protocol v1 */
139: static u_char ssh1_key[SSH_SESSION_KEY_LENGTH];
140: static u_int ssh1_keylen;
141:
1.71 markus 142: /* roundup current message to extra_pad bytes */
143: static u_char extra_pad = 0;
144:
1.105 markus 145: struct packet {
146: TAILQ_ENTRY(packet) next;
147: u_char type;
148: Buffer payload;
149: };
150: TAILQ_HEAD(, packet) outgoing;
151:
1.16 markus 152: /*
153: * Sets the descriptors used for communication. Disables encryption until
154: * packet_set_encryption_key is called.
155: */
1.2 provos 156: void
157: packet_set_connection(int fd_in, int fd_out)
1.1 deraadt 158: {
1.37 markus 159: Cipher *none = cipher_by_name("none");
1.97 deraadt 160:
1.37 markus 161: if (none == NULL)
162: fatal("packet_set_connection: cannot load cipher 'none'");
1.14 markus 163: connection_in = fd_in;
164: connection_out = fd_out;
1.113 deraadt 165: cipher_init(&send_context, none, (const u_char *)"",
166: 0, NULL, 0, CIPHER_ENCRYPT);
167: cipher_init(&receive_context, none, (const u_char *)"",
168: 0, NULL, 0, CIPHER_DECRYPT);
1.62 markus 169: newkeys[MODE_IN] = newkeys[MODE_OUT] = NULL;
1.14 markus 170: if (!initialized) {
171: initialized = 1;
172: buffer_init(&input);
173: buffer_init(&output);
174: buffer_init(&outgoing_packet);
175: buffer_init(&incoming_packet);
1.105 markus 176: TAILQ_INIT(&outgoing);
1.14 markus 177: }
1.1 deraadt 178: }
179:
1.19 markus 180: /* Returns 1 if remote host is connected via socket, 0 if not. */
181:
182: int
1.73 itojun 183: packet_connection_is_on_socket(void)
1.19 markus 184: {
185: struct sockaddr_storage from, to;
186: socklen_t fromlen, tolen;
187:
188: /* filedescriptors in and out are the same, so it's a socket */
189: if (connection_in == connection_out)
190: return 1;
191: fromlen = sizeof(from);
192: memset(&from, 0, sizeof(from));
1.20 markus 193: if (getpeername(connection_in, (struct sockaddr *)&from, &fromlen) < 0)
1.19 markus 194: return 0;
195: tolen = sizeof(to);
196: memset(&to, 0, sizeof(to));
1.20 markus 197: if (getpeername(connection_out, (struct sockaddr *)&to, &tolen) < 0)
1.19 markus 198: return 0;
199: if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0)
200: return 0;
201: if (from.ss_family != AF_INET && from.ss_family != AF_INET6)
202: return 0;
203: return 1;
204: }
205:
1.92 markus 206: /*
1.91 markus 207: * Exports an IV from the CipherContext required to export the key
208: * state back from the unprivileged child to the privileged parent
209: * process.
210: */
211:
212: void
213: packet_get_keyiv(int mode, u_char *iv, u_int len)
214: {
215: CipherContext *cc;
216:
217: if (mode == MODE_OUT)
218: cc = &send_context;
219: else
220: cc = &receive_context;
221:
222: cipher_get_keyiv(cc, iv, len);
223: }
224:
225: int
226: packet_get_keycontext(int mode, u_char *dat)
227: {
228: CipherContext *cc;
1.92 markus 229:
1.91 markus 230: if (mode == MODE_OUT)
231: cc = &send_context;
232: else
233: cc = &receive_context;
234:
235: return (cipher_get_keycontext(cc, dat));
236: }
237:
238: void
239: packet_set_keycontext(int mode, u_char *dat)
240: {
241: CipherContext *cc;
1.92 markus 242:
1.91 markus 243: if (mode == MODE_OUT)
244: cc = &send_context;
245: else
246: cc = &receive_context;
247:
248: cipher_set_keycontext(cc, dat);
249: }
250:
251: int
252: packet_get_keyiv_len(int mode)
253: {
254: CipherContext *cc;
255:
256: if (mode == MODE_OUT)
257: cc = &send_context;
258: else
259: cc = &receive_context;
260:
261: return (cipher_get_keyiv_len(cc));
262: }
263: void
264: packet_set_iv(int mode, u_char *dat)
265: {
266: CipherContext *cc;
267:
268: if (mode == MODE_OUT)
269: cc = &send_context;
270: else
271: cc = &receive_context;
272:
273: cipher_set_keyiv(cc, dat);
274: }
275: int
1.107 deraadt 276: packet_get_ssh1_cipher(void)
1.91 markus 277: {
278: return (cipher_get_number(receive_context.cipher));
279: }
280:
1.105 markus 281: void
282: packet_get_state(int mode, u_int32_t *seqnr, u_int64_t *blocks, u_int32_t *packets)
283: {
284: struct packet_state *state;
1.104 markus 285:
1.105 markus 286: state = (mode == MODE_IN) ? &p_read : &p_send;
287: *seqnr = state->seqnr;
288: *blocks = state->blocks;
289: *packets = state->packets;
1.91 markus 290: }
291:
292: void
1.105 markus 293: packet_set_state(int mode, u_int32_t seqnr, u_int64_t blocks, u_int32_t packets)
1.91 markus 294: {
1.105 markus 295: struct packet_state *state;
296:
297: state = (mode == MODE_IN) ? &p_read : &p_send;
298: state->seqnr = seqnr;
299: state->blocks = blocks;
300: state->packets = packets;
1.91 markus 301: }
302:
1.19 markus 303: /* returns 1 if connection is via ipv4 */
304:
305: int
1.73 itojun 306: packet_connection_is_ipv4(void)
1.19 markus 307: {
308: struct sockaddr_storage to;
1.21 deraadt 309: socklen_t tolen = sizeof(to);
1.19 markus 310:
311: memset(&to, 0, sizeof(to));
312: if (getsockname(connection_out, (struct sockaddr *)&to, &tolen) < 0)
313: return 0;
314: if (to.ss_family != AF_INET)
315: return 0;
316: return 1;
317: }
318:
1.1 deraadt 319: /* Sets the connection into non-blocking mode. */
320:
1.2 provos 321: void
1.73 itojun 322: packet_set_nonblocking(void)
1.1 deraadt 323: {
1.14 markus 324: /* Set the socket into non-blocking mode. */
1.114 djm 325: set_nonblock(connection_in);
1.14 markus 326:
1.114 djm 327: if (connection_out != connection_in)
328: set_nonblock(connection_out);
1.1 deraadt 329: }
330:
331: /* Returns the socket used for reading. */
332:
1.2 provos 333: int
1.73 itojun 334: packet_get_connection_in(void)
1.1 deraadt 335: {
1.14 markus 336: return connection_in;
1.1 deraadt 337: }
338:
339: /* Returns the descriptor used for writing. */
340:
1.2 provos 341: int
1.73 itojun 342: packet_get_connection_out(void)
1.1 deraadt 343: {
1.14 markus 344: return connection_out;
1.1 deraadt 345: }
346:
347: /* Closes the connection and clears and frees internal data structures. */
348:
1.2 provos 349: void
1.73 itojun 350: packet_close(void)
1.1 deraadt 351: {
1.14 markus 352: if (!initialized)
353: return;
354: initialized = 0;
355: if (connection_in == connection_out) {
356: shutdown(connection_out, SHUT_RDWR);
357: close(connection_out);
358: } else {
359: close(connection_in);
360: close(connection_out);
361: }
362: buffer_free(&input);
363: buffer_free(&output);
364: buffer_free(&outgoing_packet);
365: buffer_free(&incoming_packet);
1.60 markus 366: if (compression_buffer_ready) {
1.14 markus 367: buffer_free(&compression_buffer);
368: buffer_compress_uninit();
369: }
1.88 markus 370: cipher_cleanup(&send_context);
371: cipher_cleanup(&receive_context);
1.1 deraadt 372: }
373:
374: /* Sets remote side protocol flags. */
375:
1.2 provos 376: void
1.40 markus 377: packet_set_protocol_flags(u_int protocol_flags)
1.1 deraadt 378: {
1.14 markus 379: remote_protocol_flags = protocol_flags;
1.1 deraadt 380: }
381:
382: /* Returns the remote protocol flags set earlier by the above function. */
383:
1.40 markus 384: u_int
1.73 itojun 385: packet_get_protocol_flags(void)
1.1 deraadt 386: {
1.14 markus 387: return remote_protocol_flags;
1.1 deraadt 388: }
389:
1.16 markus 390: /*
391: * Starts packet compression from the next packet on in both directions.
392: * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip.
393: */
1.1 deraadt 394:
1.68 itojun 395: static void
396: packet_init_compression(void)
1.60 markus 397: {
398: if (compression_buffer_ready == 1)
399: return;
400: compression_buffer_ready = 1;
401: buffer_init(&compression_buffer);
402: }
403:
1.2 provos 404: void
405: packet_start_compression(int level)
1.1 deraadt 406: {
1.62 markus 407: if (packet_compression && !compat20)
1.14 markus 408: fatal("Compression already enabled.");
409: packet_compression = 1;
1.60 markus 410: packet_init_compression();
411: buffer_compress_init_send(level);
412: buffer_compress_init_recv();
1.1 deraadt 413: }
414:
1.16 markus 415: /*
416: * Causes any further packets to be encrypted using the given key. The same
417: * key is used for both sending and reception. However, both directions are
418: * encrypted independently of each other.
419: */
1.95 markus 420:
1.2 provos 421: void
1.40 markus 422: packet_set_encryption_key(const u_char *key, u_int keylen,
1.37 markus 423: int number)
1.1 deraadt 424: {
1.37 markus 425: Cipher *cipher = cipher_by_number(number);
1.97 deraadt 426:
1.37 markus 427: if (cipher == NULL)
428: fatal("packet_set_encryption_key: unknown cipher number %d", number);
1.25 markus 429: if (keylen < 20)
1.37 markus 430: fatal("packet_set_encryption_key: keylen too small: %d", keylen);
1.95 markus 431: if (keylen > SSH_SESSION_KEY_LENGTH)
432: fatal("packet_set_encryption_key: keylen too big: %d", keylen);
433: memcpy(ssh1_key, key, keylen);
434: ssh1_keylen = keylen;
1.88 markus 435: cipher_init(&send_context, cipher, key, keylen, NULL, 0, CIPHER_ENCRYPT);
436: cipher_init(&receive_context, cipher, key, keylen, NULL, 0, CIPHER_DECRYPT);
1.95 markus 437: }
438:
439: u_int
440: packet_get_encryption_key(u_char *key)
441: {
442: if (key == NULL)
443: return (ssh1_keylen);
444: memcpy(key, ssh1_key, ssh1_keylen);
445: return (ssh1_keylen);
1.1 deraadt 446: }
447:
1.62 markus 448: /* Start constructing a packet to send. */
1.2 provos 449: void
1.62 markus 450: packet_start(u_char type)
1.1 deraadt 451: {
1.62 markus 452: u_char buf[9];
453: int len;
1.1 deraadt 454:
1.62 markus 455: DBG(debug("packet_start[%d]", type));
456: len = compat20 ? 6 : 9;
457: memset(buf, 0, len - 1);
458: buf[len - 1] = type;
1.14 markus 459: buffer_clear(&outgoing_packet);
1.62 markus 460: buffer_append(&outgoing_packet, buf, len);
1.25 markus 461: }
462:
1.62 markus 463: /* Append payload. */
1.2 provos 464: void
465: packet_put_char(int value)
1.1 deraadt 466: {
1.14 markus 467: char ch = value;
1.97 deraadt 468:
1.14 markus 469: buffer_append(&outgoing_packet, &ch, 1);
1.1 deraadt 470: }
1.2 provos 471: void
1.40 markus 472: packet_put_int(u_int value)
1.1 deraadt 473: {
1.14 markus 474: buffer_put_int(&outgoing_packet, value);
1.1 deraadt 475: }
1.2 provos 476: void
1.76 stevesk 477: packet_put_string(const void *buf, u_int len)
1.1 deraadt 478: {
1.14 markus 479: buffer_put_string(&outgoing_packet, buf, len);
1.1 deraadt 480: }
1.24 markus 481: void
482: packet_put_cstring(const char *str)
483: {
1.65 markus 484: buffer_put_cstring(&outgoing_packet, str);
1.24 markus 485: }
486: void
1.76 stevesk 487: packet_put_raw(const void *buf, u_int len)
1.24 markus 488: {
489: buffer_append(&outgoing_packet, buf, len);
490: }
1.2 provos 491: void
1.14 markus 492: packet_put_bignum(BIGNUM * value)
1.1 deraadt 493: {
1.14 markus 494: buffer_put_bignum(&outgoing_packet, value);
1.1 deraadt 495: }
1.24 markus 496: void
497: packet_put_bignum2(BIGNUM * value)
498: {
499: buffer_put_bignum2(&outgoing_packet, value);
500: }
1.1 deraadt 501:
1.16 markus 502: /*
503: * Finalizes and sends the packet. If the encryption key has been set,
504: * encrypts the packet before sending.
505: */
1.14 markus 506:
1.68 itojun 507: static void
1.49 itojun 508: packet_send1(void)
1.1 deraadt 509: {
1.89 markus 510: u_char buf[8], *cp;
1.14 markus 511: int i, padding, len;
1.40 markus 512: u_int checksum;
1.115 avsm 513: u_int32_t rnd = 0;
1.14 markus 514:
1.16 markus 515: /*
516: * If using packet compression, compress the payload of the outgoing
517: * packet.
518: */
1.14 markus 519: if (packet_compression) {
520: buffer_clear(&compression_buffer);
521: /* Skip padding. */
522: buffer_consume(&outgoing_packet, 8);
523: /* padding */
524: buffer_append(&compression_buffer, "\0\0\0\0\0\0\0\0", 8);
525: buffer_compress(&outgoing_packet, &compression_buffer);
526: buffer_clear(&outgoing_packet);
527: buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer),
1.75 deraadt 528: buffer_len(&compression_buffer));
1.14 markus 529: }
530: /* Compute packet length without padding (add checksum, remove padding). */
531: len = buffer_len(&outgoing_packet) + 4 - 8;
532:
1.32 markus 533: /* Insert padding. Initialized to zero in packet_start1() */
1.14 markus 534: padding = 8 - len % 8;
1.88 markus 535: if (!send_context.plaintext) {
1.14 markus 536: cp = buffer_ptr(&outgoing_packet);
537: for (i = 0; i < padding; i++) {
538: if (i % 4 == 0)
1.115 avsm 539: rnd = arc4random();
540: cp[7 - i] = rnd & 0xff;
541: rnd >>= 8;
1.14 markus 542: }
543: }
544: buffer_consume(&outgoing_packet, 8 - padding);
545:
546: /* Add check bytes. */
1.83 stevesk 547: checksum = ssh_crc32(buffer_ptr(&outgoing_packet),
1.34 deraadt 548: buffer_len(&outgoing_packet));
1.14 markus 549: PUT_32BIT(buf, checksum);
550: buffer_append(&outgoing_packet, buf, 4);
1.1 deraadt 551:
552: #ifdef PACKET_DEBUG
1.14 markus 553: fprintf(stderr, "packet_send plain: ");
554: buffer_dump(&outgoing_packet);
1.1 deraadt 555: #endif
556:
1.14 markus 557: /* Append to output. */
558: PUT_32BIT(buf, len);
559: buffer_append(&output, buf, 4);
1.76 stevesk 560: cp = buffer_append_space(&output, buffer_len(&outgoing_packet));
1.88 markus 561: cipher_crypt(&send_context, cp, buffer_ptr(&outgoing_packet),
1.75 deraadt 562: buffer_len(&outgoing_packet));
1.14 markus 563:
1.1 deraadt 564: #ifdef PACKET_DEBUG
1.14 markus 565: fprintf(stderr, "encrypted: ");
566: buffer_dump(&output);
1.1 deraadt 567: #endif
568:
1.14 markus 569: buffer_clear(&outgoing_packet);
1.1 deraadt 570:
1.16 markus 571: /*
1.120 djm 572: * Note that the packet is now only buffered in output. It won't be
1.16 markus 573: * actually sent until packet_write_wait or packet_write_poll is
574: * called.
575: */
1.1 deraadt 576: }
577:
1.91 markus 578: void
1.57 markus 579: set_newkeys(int mode)
580: {
581: Enc *enc;
582: Mac *mac;
583: Comp *comp;
584: CipherContext *cc;
1.105 markus 585: u_int64_t *max_blocks;
1.115 avsm 586: int crypt_type;
1.57 markus 587:
1.100 markus 588: debug2("set_newkeys: mode %d", mode);
1.57 markus 589:
1.88 markus 590: if (mode == MODE_OUT) {
591: cc = &send_context;
1.115 avsm 592: crypt_type = CIPHER_ENCRYPT;
1.105 markus 593: p_send.packets = p_send.blocks = 0;
594: max_blocks = &max_blocks_out;
1.88 markus 595: } else {
596: cc = &receive_context;
1.115 avsm 597: crypt_type = CIPHER_DECRYPT;
1.105 markus 598: p_read.packets = p_read.blocks = 0;
599: max_blocks = &max_blocks_in;
1.88 markus 600: }
1.57 markus 601: if (newkeys[mode] != NULL) {
1.100 markus 602: debug("set_newkeys: rekeying");
1.88 markus 603: cipher_cleanup(cc);
1.59 markus 604: enc = &newkeys[mode]->enc;
605: mac = &newkeys[mode]->mac;
606: comp = &newkeys[mode]->comp;
1.61 markus 607: memset(mac->key, 0, mac->key_len);
1.59 markus 608: xfree(enc->name);
609: xfree(enc->iv);
610: xfree(enc->key);
611: xfree(mac->name);
612: xfree(mac->key);
613: xfree(comp->name);
1.58 markus 614: xfree(newkeys[mode]);
1.57 markus 615: }
616: newkeys[mode] = kex_get_newkeys(mode);
617: if (newkeys[mode] == NULL)
618: fatal("newkeys: no keys for mode %d", mode);
619: enc = &newkeys[mode]->enc;
620: mac = &newkeys[mode]->mac;
621: comp = &newkeys[mode]->comp;
622: if (mac->md != NULL)
623: mac->enabled = 1;
624: DBG(debug("cipher_init_context: %d", mode));
1.88 markus 625: cipher_init(cc, enc->cipher, enc->key, enc->key_len,
1.115 avsm 626: enc->iv, enc->block_size, crypt_type);
1.91 markus 627: /* Deleting the keys does not gain extra security */
628: /* memset(enc->iv, 0, enc->block_size);
629: memset(enc->key, 0, enc->key_len); */
1.118 markus 630: if ((comp->type == COMP_ZLIB ||
631: (comp->type == COMP_DELAYED && after_authentication)) &&
632: comp->enabled == 0) {
1.60 markus 633: packet_init_compression();
634: if (mode == MODE_OUT)
635: buffer_compress_init_send(6);
636: else
637: buffer_compress_init_recv();
1.57 markus 638: comp->enabled = 1;
639: }
1.109 markus 640: /*
641: * The 2^(blocksize*2) limit is too expensive for 3DES,
642: * blowfish, etc, so enforce a 1GB limit for small blocksizes.
643: */
644: if (enc->block_size >= 16)
645: *max_blocks = (u_int64_t)1 << (enc->block_size*2);
646: else
647: *max_blocks = ((u_int64_t)1 << 30) / enc->block_size;
1.105 markus 648: if (rekey_limit)
649: *max_blocks = MIN(*max_blocks, rekey_limit / enc->block_size);
1.57 markus 650: }
651:
1.16 markus 652: /*
1.118 markus 653: * Delayed compression for SSH2 is enabled after authentication:
654: * This happans on the server side after a SSH2_MSG_USERAUTH_SUCCESS is sent,
655: * and on the client side after a SSH2_MSG_USERAUTH_SUCCESS is received.
656: */
657: static void
658: packet_enable_delayed_compress(void)
659: {
660: Comp *comp = NULL;
661: int mode;
662:
663: /*
664: * Remember that we are past the authentication step, so rekeying
665: * with COMP_DELAYED will turn on compression immediately.
666: */
667: after_authentication = 1;
668: for (mode = 0; mode < MODE_MAX; mode++) {
669: comp = &newkeys[mode]->comp;
670: if (comp && !comp->enabled && comp->type == COMP_DELAYED) {
1.119 markus 671: packet_init_compression();
1.118 markus 672: if (mode == MODE_OUT)
673: buffer_compress_init_send(6);
674: else
675: buffer_compress_init_recv();
676: comp->enabled = 1;
677: }
678: }
679: }
680:
681: /*
1.25 markus 682: * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue)
683: */
1.68 itojun 684: static void
1.105 markus 685: packet_send2_wrapped(void)
1.25 markus 686: {
1.89 markus 687: u_char type, *cp, *macbuf = NULL;
1.71 markus 688: u_char padlen, pad;
1.40 markus 689: u_int packet_length = 0;
1.71 markus 690: u_int i, len;
1.115 avsm 691: u_int32_t rnd = 0;
1.25 markus 692: Enc *enc = NULL;
693: Mac *mac = NULL;
694: Comp *comp = NULL;
695: int block_size;
696:
1.57 markus 697: if (newkeys[MODE_OUT] != NULL) {
698: enc = &newkeys[MODE_OUT]->enc;
699: mac = &newkeys[MODE_OUT]->mac;
700: comp = &newkeys[MODE_OUT]->comp;
1.25 markus 701: }
1.88 markus 702: block_size = enc ? enc->block_size : 8;
1.25 markus 703:
1.89 markus 704: cp = buffer_ptr(&outgoing_packet);
705: type = cp[5];
1.25 markus 706:
707: #ifdef PACKET_DEBUG
708: fprintf(stderr, "plain: ");
709: buffer_dump(&outgoing_packet);
710: #endif
711:
712: if (comp && comp->enabled) {
713: len = buffer_len(&outgoing_packet);
714: /* skip header, compress only payload */
715: buffer_consume(&outgoing_packet, 5);
716: buffer_clear(&compression_buffer);
717: buffer_compress(&outgoing_packet, &compression_buffer);
718: buffer_clear(&outgoing_packet);
719: buffer_append(&outgoing_packet, "\0\0\0\0\0", 5);
720: buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer),
721: buffer_len(&compression_buffer));
722: DBG(debug("compression: raw %d compressed %d", len,
723: buffer_len(&outgoing_packet)));
724: }
725:
726: /* sizeof (packet_len + pad_len + payload) */
727: len = buffer_len(&outgoing_packet);
728:
729: /*
730: * calc size of padding, alloc space, get random data,
731: * minimum padding is 4 bytes
732: */
733: padlen = block_size - (len % block_size);
734: if (padlen < 4)
735: padlen += block_size;
1.71 markus 736: if (extra_pad) {
737: /* will wrap if extra_pad+padlen > 255 */
738: extra_pad = roundup(extra_pad, block_size);
739: pad = extra_pad - ((len + padlen) % extra_pad);
1.93 markus 740: debug3("packet_send2: adding %d (len %d padlen %d extra_pad %d)",
1.71 markus 741: pad, len, padlen, extra_pad);
742: padlen += pad;
743: extra_pad = 0;
744: }
1.76 stevesk 745: cp = buffer_append_space(&outgoing_packet, padlen);
1.88 markus 746: if (enc && !send_context.plaintext) {
1.32 markus 747: /* random padding */
1.25 markus 748: for (i = 0; i < padlen; i++) {
749: if (i % 4 == 0)
1.115 avsm 750: rnd = arc4random();
751: cp[i] = rnd & 0xff;
752: rnd >>= 8;
1.25 markus 753: }
1.32 markus 754: } else {
755: /* clear padding */
756: memset(cp, 0, padlen);
1.25 markus 757: }
758: /* packet_length includes payload, padding and padding length field */
759: packet_length = buffer_len(&outgoing_packet) - 4;
1.89 markus 760: cp = buffer_ptr(&outgoing_packet);
761: PUT_32BIT(cp, packet_length);
762: cp[4] = padlen;
1.25 markus 763: DBG(debug("send: len %d (includes padlen %d)", packet_length+4, padlen));
764:
765: /* compute MAC over seqnr and packet(length fields, payload, padding) */
766: if (mac && mac->enabled) {
1.105 markus 767: macbuf = mac_compute(mac, p_send.seqnr,
1.83 stevesk 768: buffer_ptr(&outgoing_packet),
1.50 markus 769: buffer_len(&outgoing_packet));
1.105 markus 770: DBG(debug("done calc MAC out #%d", p_send.seqnr));
1.25 markus 771: }
772: /* encrypt packet and append to output buffer. */
1.76 stevesk 773: cp = buffer_append_space(&output, buffer_len(&outgoing_packet));
1.88 markus 774: cipher_crypt(&send_context, cp, buffer_ptr(&outgoing_packet),
1.25 markus 775: buffer_len(&outgoing_packet));
776: /* append unencrypted MAC */
777: if (mac && mac->enabled)
778: buffer_append(&output, (char *)macbuf, mac->mac_len);
779: #ifdef PACKET_DEBUG
780: fprintf(stderr, "encrypted: ");
781: buffer_dump(&output);
782: #endif
1.29 markus 783: /* increment sequence number for outgoing packets */
1.105 markus 784: if (++p_send.seqnr == 0)
1.106 itojun 785: logit("outgoing seqnr wraps around");
1.105 markus 786: if (++p_send.packets == 0)
787: if (!(datafellows & SSH_BUG_NOREKEY))
788: fatal("XXX too many packets with same key");
789: p_send.blocks += (packet_length + 4) / block_size;
1.25 markus 790: buffer_clear(&outgoing_packet);
791:
1.57 markus 792: if (type == SSH2_MSG_NEWKEYS)
793: set_newkeys(MODE_OUT);
1.118 markus 794: else if (type == SSH2_MSG_USERAUTH_SUCCESS && server_side)
795: packet_enable_delayed_compress();
1.25 markus 796: }
797:
1.105 markus 798: static void
799: packet_send2(void)
800: {
801: static int rekeying = 0;
802: struct packet *p;
803: u_char type, *cp;
804:
805: cp = buffer_ptr(&outgoing_packet);
806: type = cp[5];
807:
808: /* during rekeying we can only send key exchange messages */
809: if (rekeying) {
810: if (!((type >= SSH2_MSG_TRANSPORT_MIN) &&
811: (type <= SSH2_MSG_TRANSPORT_MAX))) {
812: debug("enqueue packet: %u", type);
813: p = xmalloc(sizeof(*p));
814: p->type = type;
815: memcpy(&p->payload, &outgoing_packet, sizeof(Buffer));
816: buffer_init(&outgoing_packet);
817: TAILQ_INSERT_TAIL(&outgoing, p, next);
818: return;
819: }
820: }
821:
822: /* rekeying starts with sending KEXINIT */
823: if (type == SSH2_MSG_KEXINIT)
824: rekeying = 1;
825:
826: packet_send2_wrapped();
827:
828: /* after a NEWKEYS message we can send the complete queue */
829: if (type == SSH2_MSG_NEWKEYS) {
830: rekeying = 0;
831: while ((p = TAILQ_FIRST(&outgoing))) {
832: type = p->type;
833: debug("dequeue packet: %u", type);
834: buffer_free(&outgoing_packet);
835: memcpy(&outgoing_packet, &p->payload,
836: sizeof(Buffer));
837: TAILQ_REMOVE(&outgoing, p, next);
838: xfree(p);
839: packet_send2_wrapped();
840: }
841: }
842: }
843:
1.25 markus 844: void
1.73 itojun 845: packet_send(void)
1.25 markus 846: {
1.62 markus 847: if (compat20)
1.25 markus 848: packet_send2();
849: else
850: packet_send1();
851: DBG(debug("packet_send done"));
852: }
853:
854: /*
1.16 markus 855: * Waits until a packet has been received, and returns its type. Note that
856: * no other data is processed until this returns, so this function should not
857: * be used during the interactive session.
858: */
1.1 deraadt 859:
1.2 provos 860: int
1.82 markus 861: packet_read_seqnr(u_int32_t *seqnr_p)
1.1 deraadt 862: {
1.14 markus 863: int type, len;
1.56 millert 864: fd_set *setp;
1.14 markus 865: char buf[8192];
1.25 markus 866: DBG(debug("packet_read()"));
1.14 markus 867:
1.56 millert 868: setp = (fd_set *)xmalloc(howmany(connection_in+1, NFDBITS) *
869: sizeof(fd_mask));
870:
1.14 markus 871: /* Since we are blocking, ensure that all written packets have been sent. */
872: packet_write_wait();
873:
874: /* Stay in the loop until we have received a complete packet. */
875: for (;;) {
876: /* Try to read a packet from the buffer. */
1.82 markus 877: type = packet_read_poll_seqnr(seqnr_p);
1.62 markus 878: if (!compat20 && (
1.32 markus 879: type == SSH_SMSG_SUCCESS
1.14 markus 880: || type == SSH_SMSG_FAILURE
881: || type == SSH_CMSG_EOF
1.32 markus 882: || type == SSH_CMSG_EXIT_CONFIRMATION))
1.79 markus 883: packet_check_eom();
1.14 markus 884: /* If we got a packet, return it. */
1.56 millert 885: if (type != SSH_MSG_NONE) {
886: xfree(setp);
1.14 markus 887: return type;
1.56 millert 888: }
1.16 markus 889: /*
890: * Otherwise, wait for some data to arrive, add it to the
891: * buffer, and try again.
892: */
1.56 millert 893: memset(setp, 0, howmany(connection_in + 1, NFDBITS) *
894: sizeof(fd_mask));
895: FD_SET(connection_in, setp);
1.16 markus 896:
1.14 markus 897: /* Wait for some data to arrive. */
1.56 millert 898: while (select(connection_in + 1, setp, NULL, NULL, NULL) == -1 &&
1.51 deraadt 899: (errno == EAGAIN || errno == EINTR))
900: ;
1.16 markus 901:
1.14 markus 902: /* Read data from the socket. */
903: len = read(connection_in, buf, sizeof(buf));
1.18 markus 904: if (len == 0) {
1.106 itojun 905: logit("Connection closed by %.200s", get_remote_ipaddr());
1.112 markus 906: cleanup_exit(255);
1.18 markus 907: }
1.14 markus 908: if (len < 0)
909: fatal("Read from socket failed: %.100s", strerror(errno));
910: /* Append it to the buffer. */
911: packet_process_incoming(buf, len);
912: }
913: /* NOTREACHED */
1.1 deraadt 914: }
915:
1.77 djm 916: int
1.82 markus 917: packet_read(void)
1.77 djm 918: {
1.82 markus 919: return packet_read_seqnr(NULL);
1.77 djm 920: }
921:
1.16 markus 922: /*
923: * Waits until a packet has been received, verifies that its type matches
924: * that given, and gives a fatal error and exits if there is a mismatch.
925: */
1.1 deraadt 926:
1.2 provos 927: void
1.82 markus 928: packet_read_expect(int expected_type)
1.1 deraadt 929: {
1.14 markus 930: int type;
1.1 deraadt 931:
1.82 markus 932: type = packet_read();
1.14 markus 933: if (type != expected_type)
934: packet_disconnect("Protocol error: expected packet type %d, got %d",
1.25 markus 935: expected_type, type);
1.1 deraadt 936: }
937:
938: /* Checks if a full packet is available in the data received so far via
1.14 markus 939: * packet_process_incoming. If so, reads the packet; otherwise returns
940: * SSH_MSG_NONE. This does not wait for data from the connection.
941: *
942: * SSH_MSG_DISCONNECT is handled specially here. Also,
943: * SSH_MSG_IGNORE messages are skipped by this function and are never returned
944: * to higher levels.
945: */
1.1 deraadt 946:
1.68 itojun 947: static int
1.82 markus 948: packet_read_poll1(void)
1.1 deraadt 949: {
1.40 markus 950: u_int len, padded_len;
1.89 markus 951: u_char *cp, type;
1.40 markus 952: u_int checksum, stored_checksum;
1.14 markus 953:
954: /* Check if input size is less than minimum packet size. */
955: if (buffer_len(&input) < 4 + 8)
956: return SSH_MSG_NONE;
957: /* Get length of incoming packet. */
1.89 markus 958: cp = buffer_ptr(&input);
959: len = GET_32BIT(cp);
1.14 markus 960: if (len < 1 + 2 + 2 || len > 256 * 1024)
1.98 markus 961: packet_disconnect("Bad packet length %u.", len);
1.14 markus 962: padded_len = (len + 8) & ~7;
963:
964: /* Check if the packet has been entirely received. */
965: if (buffer_len(&input) < 4 + padded_len)
966: return SSH_MSG_NONE;
967:
968: /* The entire packet is in buffer. */
969:
970: /* Consume packet length. */
971: buffer_consume(&input, 4);
972:
1.62 markus 973: /*
974: * Cryptographic attack detector for ssh
975: * (C)1998 CORE-SDI, Buenos Aires Argentina
976: * Ariel Futoransky(futo@core-sdi.com)
977: */
1.88 markus 978: if (!receive_context.plaintext &&
1.62 markus 979: detect_attack(buffer_ptr(&input), padded_len, NULL) == DEATTACK_DETECTED)
980: packet_disconnect("crc32 compensation attack: network attack detected");
981:
982: /* Decrypt data to incoming_packet. */
1.14 markus 983: buffer_clear(&incoming_packet);
1.76 stevesk 984: cp = buffer_append_space(&incoming_packet, padded_len);
1.88 markus 985: cipher_crypt(&receive_context, cp, buffer_ptr(&input), padded_len);
1.62 markus 986:
1.14 markus 987: buffer_consume(&input, padded_len);
1.1 deraadt 988:
989: #ifdef PACKET_DEBUG
1.14 markus 990: fprintf(stderr, "read_poll plain: ");
991: buffer_dump(&incoming_packet);
1.1 deraadt 992: #endif
993:
1.14 markus 994: /* Compute packet checksum. */
1.83 stevesk 995: checksum = ssh_crc32(buffer_ptr(&incoming_packet),
1.25 markus 996: buffer_len(&incoming_packet) - 4);
1.14 markus 997:
998: /* Skip padding. */
999: buffer_consume(&incoming_packet, 8 - len % 8);
1000:
1001: /* Test check bytes. */
1002: if (len != buffer_len(&incoming_packet))
1.77 djm 1003: packet_disconnect("packet_read_poll1: len %d != buffer_len %d.",
1.25 markus 1004: len, buffer_len(&incoming_packet));
1.14 markus 1005:
1.89 markus 1006: cp = (u_char *)buffer_ptr(&incoming_packet) + len - 4;
1007: stored_checksum = GET_32BIT(cp);
1.14 markus 1008: if (checksum != stored_checksum)
1009: packet_disconnect("Corrupted check bytes on input.");
1010: buffer_consume_end(&incoming_packet, 4);
1011:
1012: if (packet_compression) {
1013: buffer_clear(&compression_buffer);
1014: buffer_uncompress(&incoming_packet, &compression_buffer);
1015: buffer_clear(&incoming_packet);
1016: buffer_append(&incoming_packet, buffer_ptr(&compression_buffer),
1.25 markus 1017: buffer_len(&compression_buffer));
1.14 markus 1018: }
1.62 markus 1019: type = buffer_get_char(&incoming_packet);
1.116 markus 1020: if (type < SSH_MSG_MIN || type > SSH_MSG_MAX)
1021: packet_disconnect("Invalid ssh1 packet type: %d", type);
1.62 markus 1022: return type;
1.1 deraadt 1023: }
1.14 markus 1024:
1.68 itojun 1025: static int
1.82 markus 1026: packet_read_poll2(u_int32_t *seqnr_p)
1.25 markus 1027: {
1.50 markus 1028: static u_int packet_length = 0;
1.40 markus 1029: u_int padlen, need;
1.89 markus 1030: u_char *macbuf, *cp, type;
1.117 djm 1031: u_int maclen, block_size;
1.25 markus 1032: Enc *enc = NULL;
1033: Mac *mac = NULL;
1034: Comp *comp = NULL;
1035:
1.57 markus 1036: if (newkeys[MODE_IN] != NULL) {
1037: enc = &newkeys[MODE_IN]->enc;
1038: mac = &newkeys[MODE_IN]->mac;
1039: comp = &newkeys[MODE_IN]->comp;
1.25 markus 1040: }
1041: maclen = mac && mac->enabled ? mac->mac_len : 0;
1.88 markus 1042: block_size = enc ? enc->block_size : 8;
1.25 markus 1043:
1044: if (packet_length == 0) {
1045: /*
1046: * check if input size is less than the cipher block size,
1047: * decrypt first block and extract length of incoming packet
1048: */
1049: if (buffer_len(&input) < block_size)
1050: return SSH_MSG_NONE;
1051: buffer_clear(&incoming_packet);
1.76 stevesk 1052: cp = buffer_append_space(&incoming_packet, block_size);
1.88 markus 1053: cipher_crypt(&receive_context, cp, buffer_ptr(&input),
1.25 markus 1054: block_size);
1.89 markus 1055: cp = buffer_ptr(&incoming_packet);
1056: packet_length = GET_32BIT(cp);
1.25 markus 1057: if (packet_length < 1 + 4 || packet_length > 256 * 1024) {
1.110 markus 1058: #ifdef PACKET_DEBUG
1.25 markus 1059: buffer_dump(&incoming_packet);
1.110 markus 1060: #endif
1.98 markus 1061: packet_disconnect("Bad packet length %u.", packet_length);
1.25 markus 1062: }
1.98 markus 1063: DBG(debug("input: packet len %u", packet_length+4));
1.25 markus 1064: buffer_consume(&input, block_size);
1065: }
1066: /* we have a partial packet of block_size bytes */
1067: need = 4 + packet_length - block_size;
1068: DBG(debug("partial packet %d, need %d, maclen %d", block_size,
1069: need, maclen));
1070: if (need % block_size != 0)
1071: fatal("padding error: need %d block %d mod %d",
1072: need, block_size, need % block_size);
1073: /*
1074: * check if the entire packet has been received and
1075: * decrypt into incoming_packet
1076: */
1077: if (buffer_len(&input) < need + maclen)
1078: return SSH_MSG_NONE;
1079: #ifdef PACKET_DEBUG
1080: fprintf(stderr, "read_poll enc/full: ");
1081: buffer_dump(&input);
1082: #endif
1.76 stevesk 1083: cp = buffer_append_space(&incoming_packet, need);
1.88 markus 1084: cipher_crypt(&receive_context, cp, buffer_ptr(&input), need);
1.25 markus 1085: buffer_consume(&input, need);
1086: /*
1087: * compute MAC over seqnr and packet,
1088: * increment sequence number for incoming packet
1089: */
1.29 markus 1090: if (mac && mac->enabled) {
1.105 markus 1091: macbuf = mac_compute(mac, p_read.seqnr,
1.83 stevesk 1092: buffer_ptr(&incoming_packet),
1.50 markus 1093: buffer_len(&incoming_packet));
1.25 markus 1094: if (memcmp(macbuf, buffer_ptr(&input), mac->mac_len) != 0)
1.36 markus 1095: packet_disconnect("Corrupted MAC on input.");
1.105 markus 1096: DBG(debug("MAC #%d ok", p_read.seqnr));
1.25 markus 1097: buffer_consume(&input, mac->mac_len);
1098: }
1.77 djm 1099: if (seqnr_p != NULL)
1.105 markus 1100: *seqnr_p = p_read.seqnr;
1101: if (++p_read.seqnr == 0)
1.106 itojun 1102: logit("incoming seqnr wraps around");
1.105 markus 1103: if (++p_read.packets == 0)
1104: if (!(datafellows & SSH_BUG_NOREKEY))
1105: fatal("XXX too many packets with same key");
1106: p_read.blocks += (packet_length + 4) / block_size;
1.25 markus 1107:
1108: /* get padlen */
1.76 stevesk 1109: cp = buffer_ptr(&incoming_packet);
1.89 markus 1110: padlen = cp[4];
1.25 markus 1111: DBG(debug("input: padlen %d", padlen));
1112: if (padlen < 4)
1113: packet_disconnect("Corrupted padlen %d on input.", padlen);
1114:
1115: /* skip packet size + padlen, discard padding */
1116: buffer_consume(&incoming_packet, 4 + 1);
1117: buffer_consume_end(&incoming_packet, padlen);
1118:
1119: DBG(debug("input: len before de-compress %d", buffer_len(&incoming_packet)));
1120: if (comp && comp->enabled) {
1121: buffer_clear(&compression_buffer);
1122: buffer_uncompress(&incoming_packet, &compression_buffer);
1123: buffer_clear(&incoming_packet);
1124: buffer_append(&incoming_packet, buffer_ptr(&compression_buffer),
1125: buffer_len(&compression_buffer));
1.97 deraadt 1126: DBG(debug("input: len after de-compress %d",
1127: buffer_len(&incoming_packet)));
1.25 markus 1128: }
1129: /*
1130: * get packet type, implies consume.
1131: * return length of payload (without type field)
1132: */
1.62 markus 1133: type = buffer_get_char(&incoming_packet);
1.116 markus 1134: if (type < SSH2_MSG_MIN || type >= SSH2_MSG_LOCAL_MIN)
1135: packet_disconnect("Invalid ssh2 packet type: %d", type);
1.57 markus 1136: if (type == SSH2_MSG_NEWKEYS)
1137: set_newkeys(MODE_IN);
1.118 markus 1138: else if (type == SSH2_MSG_USERAUTH_SUCCESS && !server_side)
1139: packet_enable_delayed_compress();
1.25 markus 1140: #ifdef PACKET_DEBUG
1.55 deraadt 1141: fprintf(stderr, "read/plain[%d]:\r\n", type);
1.25 markus 1142: buffer_dump(&incoming_packet);
1143: #endif
1.62 markus 1144: /* reset for next packet */
1145: packet_length = 0;
1146: return type;
1.25 markus 1147: }
1148:
1149: int
1.82 markus 1150: packet_read_poll_seqnr(u_int32_t *seqnr_p)
1.25 markus 1151: {
1.96 deraadt 1152: u_int reason, seqnr;
1.62 markus 1153: u_char type;
1.25 markus 1154: char *msg;
1.62 markus 1155:
1.25 markus 1156: for (;;) {
1.62 markus 1157: if (compat20) {
1.82 markus 1158: type = packet_read_poll2(seqnr_p);
1.62 markus 1159: if (type)
1.25 markus 1160: DBG(debug("received packet type %d", type));
1.74 deraadt 1161: switch (type) {
1.25 markus 1162: case SSH2_MSG_IGNORE:
1163: break;
1164: case SSH2_MSG_DEBUG:
1165: packet_get_char();
1166: msg = packet_get_string(NULL);
1167: debug("Remote: %.900s", msg);
1168: xfree(msg);
1169: msg = packet_get_string(NULL);
1170: xfree(msg);
1171: break;
1172: case SSH2_MSG_DISCONNECT:
1173: reason = packet_get_int();
1174: msg = packet_get_string(NULL);
1.106 itojun 1175: logit("Received disconnect from %s: %u: %.400s",
1.96 deraadt 1176: get_remote_ipaddr(), reason, msg);
1.25 markus 1177: xfree(msg);
1.112 markus 1178: cleanup_exit(255);
1.84 markus 1179: break;
1180: case SSH2_MSG_UNIMPLEMENTED:
1181: seqnr = packet_get_int();
1.96 deraadt 1182: debug("Received SSH2_MSG_UNIMPLEMENTED for %u",
1183: seqnr);
1.25 markus 1184: break;
1185: default:
1186: return type;
1187: break;
1.48 stevesk 1188: }
1.25 markus 1189: } else {
1.82 markus 1190: type = packet_read_poll1();
1.74 deraadt 1191: switch (type) {
1.25 markus 1192: case SSH_MSG_IGNORE:
1193: break;
1194: case SSH_MSG_DEBUG:
1195: msg = packet_get_string(NULL);
1196: debug("Remote: %.900s", msg);
1197: xfree(msg);
1198: break;
1199: case SSH_MSG_DISCONNECT:
1200: msg = packet_get_string(NULL);
1.106 itojun 1201: logit("Received disconnect from %s: %.400s",
1.96 deraadt 1202: get_remote_ipaddr(), msg);
1.112 markus 1203: cleanup_exit(255);
1.25 markus 1204: xfree(msg);
1205: break;
1206: default:
1.62 markus 1207: if (type)
1.25 markus 1208: DBG(debug("received packet type %d", type));
1209: return type;
1210: break;
1.48 stevesk 1211: }
1.25 markus 1212: }
1213: }
1.77 djm 1214: }
1215:
1216: int
1.82 markus 1217: packet_read_poll(void)
1.77 djm 1218: {
1.82 markus 1219: return packet_read_poll_seqnr(NULL);
1.25 markus 1220: }
1221:
1.16 markus 1222: /*
1223: * Buffers the given amount of input characters. This is intended to be used
1224: * together with packet_read_poll.
1225: */
1.1 deraadt 1226:
1.2 provos 1227: void
1.40 markus 1228: packet_process_incoming(const char *buf, u_int len)
1.1 deraadt 1229: {
1.14 markus 1230: buffer_append(&input, buf, len);
1.1 deraadt 1231: }
1232:
1233: /* Returns a character from the packet. */
1234:
1.40 markus 1235: u_int
1.73 itojun 1236: packet_get_char(void)
1.1 deraadt 1237: {
1.14 markus 1238: char ch;
1.97 deraadt 1239:
1.14 markus 1240: buffer_get(&incoming_packet, &ch, 1);
1.40 markus 1241: return (u_char) ch;
1.1 deraadt 1242: }
1243:
1244: /* Returns an integer from the packet data. */
1245:
1.40 markus 1246: u_int
1.73 itojun 1247: packet_get_int(void)
1.1 deraadt 1248: {
1.14 markus 1249: return buffer_get_int(&incoming_packet);
1.1 deraadt 1250: }
1251:
1.16 markus 1252: /*
1253: * Returns an arbitrary precision integer from the packet data. The integer
1254: * must have been initialized before this call.
1255: */
1.1 deraadt 1256:
1.2 provos 1257: void
1.80 markus 1258: packet_get_bignum(BIGNUM * value)
1.1 deraadt 1259: {
1.81 markus 1260: buffer_get_bignum(&incoming_packet, value);
1.24 markus 1261: }
1262:
1263: void
1.80 markus 1264: packet_get_bignum2(BIGNUM * value)
1.24 markus 1265: {
1.81 markus 1266: buffer_get_bignum2(&incoming_packet, value);
1.24 markus 1267: }
1268:
1.76 stevesk 1269: void *
1.117 djm 1270: packet_get_raw(u_int *length_ptr)
1.24 markus 1271: {
1.117 djm 1272: u_int bytes = buffer_len(&incoming_packet);
1.97 deraadt 1273:
1.24 markus 1274: if (length_ptr != NULL)
1275: *length_ptr = bytes;
1276: return buffer_ptr(&incoming_packet);
1.28 markus 1277: }
1278:
1279: int
1280: packet_remaining(void)
1281: {
1282: return buffer_len(&incoming_packet);
1.1 deraadt 1283: }
1284:
1.16 markus 1285: /*
1286: * Returns a string from the packet data. The string is allocated using
1287: * xmalloc; it is the responsibility of the calling program to free it when
1288: * no longer needed. The length_ptr argument may be NULL, or point to an
1289: * integer into which the length of the string is stored.
1290: */
1.1 deraadt 1291:
1.76 stevesk 1292: void *
1.40 markus 1293: packet_get_string(u_int *length_ptr)
1.1 deraadt 1294: {
1.14 markus 1295: return buffer_get_string(&incoming_packet, length_ptr);
1.1 deraadt 1296: }
1297:
1.16 markus 1298: /*
1299: * Sends a diagnostic message from the server to the client. This message
1300: * can be sent at any time (but not while constructing another message). The
1301: * message is printed immediately, but only if the client is being executed
1302: * in verbose mode. These messages are primarily intended to ease debugging
1303: * authentication problems. The length of the formatted message must not
1304: * exceed 1024 bytes. This will automatically call packet_write_wait.
1305: */
1.1 deraadt 1306:
1.2 provos 1307: void
1.14 markus 1308: packet_send_debug(const char *fmt,...)
1.1 deraadt 1309: {
1.14 markus 1310: char buf[1024];
1311: va_list args;
1.39 markus 1312:
1313: if (compat20 && (datafellows & SSH_BUG_DEBUG))
1314: return;
1.14 markus 1315:
1316: va_start(args, fmt);
1317: vsnprintf(buf, sizeof(buf), fmt, args);
1318: va_end(args);
1319:
1.30 markus 1320: if (compat20) {
1321: packet_start(SSH2_MSG_DEBUG);
1322: packet_put_char(0); /* bool: always display */
1323: packet_put_cstring(buf);
1324: packet_put_cstring("");
1325: } else {
1326: packet_start(SSH_MSG_DEBUG);
1327: packet_put_cstring(buf);
1328: }
1.14 markus 1329: packet_send();
1330: packet_write_wait();
1.1 deraadt 1331: }
1332:
1.16 markus 1333: /*
1334: * Logs the error plus constructs and sends a disconnect packet, closes the
1335: * connection, and exits. This function never returns. The error message
1336: * should not contain a newline. The length of the formatted message must
1337: * not exceed 1024 bytes.
1338: */
1.1 deraadt 1339:
1.2 provos 1340: void
1.14 markus 1341: packet_disconnect(const char *fmt,...)
1.1 deraadt 1342: {
1.14 markus 1343: char buf[1024];
1344: va_list args;
1345: static int disconnecting = 0;
1.97 deraadt 1346:
1.14 markus 1347: if (disconnecting) /* Guard against recursive invocations. */
1348: fatal("packet_disconnect called recursively.");
1349: disconnecting = 1;
1350:
1.16 markus 1351: /*
1352: * Format the message. Note that the caller must make sure the
1353: * message is of limited size.
1354: */
1.14 markus 1355: va_start(args, fmt);
1356: vsnprintf(buf, sizeof(buf), fmt, args);
1357: va_end(args);
1358:
1.99 markus 1359: /* Display the error locally */
1.106 itojun 1360: logit("Disconnecting: %.100s", buf);
1.99 markus 1361:
1.14 markus 1362: /* Send the disconnect message to the other side, and wait for it to get sent. */
1.25 markus 1363: if (compat20) {
1364: packet_start(SSH2_MSG_DISCONNECT);
1365: packet_put_int(SSH2_DISCONNECT_PROTOCOL_ERROR);
1366: packet_put_cstring(buf);
1367: packet_put_cstring("");
1368: } else {
1369: packet_start(SSH_MSG_DISCONNECT);
1.65 markus 1370: packet_put_cstring(buf);
1.25 markus 1371: }
1.14 markus 1372: packet_send();
1373: packet_write_wait();
1374:
1375: /* Stop listening for connections. */
1.67 markus 1376: channel_close_all();
1.14 markus 1377:
1378: /* Close the connection. */
1379: packet_close();
1.112 markus 1380: cleanup_exit(255);
1.1 deraadt 1381: }
1382:
1.16 markus 1383: /* Checks if there is any buffered output, and tries to write some of the output. */
1.1 deraadt 1384:
1.2 provos 1385: void
1.73 itojun 1386: packet_write_poll(void)
1.1 deraadt 1387: {
1.14 markus 1388: int len = buffer_len(&output);
1.97 deraadt 1389:
1.14 markus 1390: if (len > 0) {
1391: len = write(connection_out, buffer_ptr(&output), len);
1392: if (len <= 0) {
1393: if (errno == EAGAIN)
1394: return;
1395: else
1396: fatal("Write failed: %.100s", strerror(errno));
1397: }
1398: buffer_consume(&output, len);
1399: }
1.1 deraadt 1400: }
1401:
1.16 markus 1402: /*
1403: * Calls packet_write_poll repeatedly until all pending output data has been
1404: * written.
1405: */
1.1 deraadt 1406:
1.2 provos 1407: void
1.73 itojun 1408: packet_write_wait(void)
1.1 deraadt 1409: {
1.56 millert 1410: fd_set *setp;
1411:
1412: setp = (fd_set *)xmalloc(howmany(connection_out + 1, NFDBITS) *
1413: sizeof(fd_mask));
1.14 markus 1414: packet_write_poll();
1415: while (packet_have_data_to_write()) {
1.56 millert 1416: memset(setp, 0, howmany(connection_out + 1, NFDBITS) *
1417: sizeof(fd_mask));
1418: FD_SET(connection_out, setp);
1419: while (select(connection_out + 1, NULL, setp, NULL, NULL) == -1 &&
1.51 deraadt 1420: (errno == EAGAIN || errno == EINTR))
1421: ;
1.14 markus 1422: packet_write_poll();
1423: }
1.56 millert 1424: xfree(setp);
1.1 deraadt 1425: }
1426:
1427: /* Returns true if there is buffered data to write to the connection. */
1428:
1.2 provos 1429: int
1.73 itojun 1430: packet_have_data_to_write(void)
1.1 deraadt 1431: {
1.14 markus 1432: return buffer_len(&output) != 0;
1.1 deraadt 1433: }
1434:
1435: /* Returns true if there is not too much data to write to the connection. */
1436:
1.2 provos 1437: int
1.73 itojun 1438: packet_not_very_much_data_to_write(void)
1.1 deraadt 1439: {
1.14 markus 1440: if (interactive_mode)
1441: return buffer_len(&output) < 16384;
1442: else
1443: return buffer_len(&output) < 128 * 1024;
1.1 deraadt 1444: }
1445:
1.102 markus 1446: static void
1.101 markus 1447: packet_set_tos(int interactive)
1448: {
1449: int tos = interactive ? IPTOS_LOWDELAY : IPTOS_THROUGHPUT;
1450:
1451: if (!packet_connection_is_on_socket() ||
1452: !packet_connection_is_ipv4())
1453: return;
1454: if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, &tos,
1455: sizeof(tos)) < 0)
1456: error("setsockopt IP_TOS %d: %.100s:",
1457: tos, strerror(errno));
1458: }
1459:
1.1 deraadt 1460: /* Informs that the current session is interactive. Sets IP flags for that. */
1461:
1.2 provos 1462: void
1.43 markus 1463: packet_set_interactive(int interactive)
1.1 deraadt 1464: {
1.43 markus 1465: static int called = 0;
1.44 markus 1466:
1.43 markus 1467: if (called)
1468: return;
1469: called = 1;
1.1 deraadt 1470:
1.14 markus 1471: /* Record that we are in interactive mode. */
1472: interactive_mode = interactive;
1.1 deraadt 1473:
1.19 markus 1474: /* Only set socket options if using a socket. */
1475: if (!packet_connection_is_on_socket())
1.14 markus 1476: return;
1.122 dtucker 1477: set_nodelay(connection_in);
1.101 markus 1478: packet_set_tos(interactive);
1.1 deraadt 1479: }
1480:
1481: /* Returns true if the current connection is interactive. */
1482:
1.2 provos 1483: int
1.73 itojun 1484: packet_is_interactive(void)
1.1 deraadt 1485: {
1.14 markus 1486: return interactive_mode;
1.12 markus 1487: }
1488:
1.113 deraadt 1489: int
1.108 markus 1490: packet_set_maxsize(u_int s)
1.12 markus 1491: {
1.14 markus 1492: static int called = 0;
1.97 deraadt 1493:
1.14 markus 1494: if (called) {
1.106 itojun 1495: logit("packet_set_maxsize: called twice: old %d new %d",
1.25 markus 1496: max_packet_size, s);
1.14 markus 1497: return -1;
1498: }
1499: if (s < 4 * 1024 || s > 1024 * 1024) {
1.106 itojun 1500: logit("packet_set_maxsize: bad size %d", s);
1.14 markus 1501: return -1;
1502: }
1.70 markus 1503: called = 1;
1.66 markus 1504: debug("packet_set_maxsize: setting to %d", s);
1.14 markus 1505: max_packet_size = s;
1506: return s;
1.53 markus 1507: }
1508:
1.71 markus 1509: /* roundup current message to pad bytes */
1510: void
1511: packet_add_padding(u_char pad)
1512: {
1513: extra_pad = pad;
1514: }
1515:
1.53 markus 1516: /*
1517: * 9.2. Ignored Data Message
1.61 markus 1518: *
1.53 markus 1519: * byte SSH_MSG_IGNORE
1520: * string data
1.61 markus 1521: *
1.53 markus 1522: * All implementations MUST understand (and ignore) this message at any
1523: * time (after receiving the protocol version). No implementation is
1524: * required to send them. This message can be used as an additional
1525: * protection measure against advanced traffic analysis techniques.
1526: */
1.54 markus 1527: void
1528: packet_send_ignore(int nbytes)
1529: {
1.115 avsm 1530: u_int32_t rnd = 0;
1.54 markus 1531: int i;
1532:
1533: packet_start(compat20 ? SSH2_MSG_IGNORE : SSH_MSG_IGNORE);
1.53 markus 1534: packet_put_int(nbytes);
1.75 deraadt 1535: for (i = 0; i < nbytes; i++) {
1.53 markus 1536: if (i % 4 == 0)
1.115 avsm 1537: rnd = arc4random();
1538: packet_put_char(rnd & 0xff);
1539: rnd >>= 8;
1.53 markus 1540: }
1.105 markus 1541: }
1542:
1.113 deraadt 1543: #define MAX_PACKETS (1U<<31)
1.105 markus 1544: int
1545: packet_need_rekeying(void)
1546: {
1547: if (datafellows & SSH_BUG_NOREKEY)
1548: return 0;
1549: return
1550: (p_send.packets > MAX_PACKETS) ||
1551: (p_read.packets > MAX_PACKETS) ||
1552: (max_blocks_out && (p_send.blocks > max_blocks_out)) ||
1553: (max_blocks_in && (p_read.blocks > max_blocks_in));
1554: }
1555:
1556: void
1557: packet_set_rekey_limit(u_int32_t bytes)
1558: {
1559: rekey_limit = bytes;
1.118 markus 1560: }
1561:
1562: void
1563: packet_set_server(void)
1564: {
1565: server_side = 1;
1566: }
1567:
1568: void
1569: packet_set_authenticated(void)
1570: {
1571: after_authentication = 1;
1.1 deraadt 1572: }
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