Annotation of src/usr.bin/ssh/packet.c, Revision 1.59
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.
1.35 deraadt 16: * Copyright (c) 2000 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"
1.59 ! markus 40: RCSID("$OpenBSD: packet.c,v 1.58 2001/04/04 09:48:34 markus Exp $");
1.1 deraadt 41:
42: #include "xmalloc.h"
43: #include "buffer.h"
44: #include "packet.h"
45: #include "bufaux.h"
46: #include "crc32.h"
47: #include "getput.h"
48:
49: #include "compress.h"
1.9 dugsong 50: #include "deattack.h"
1.23 markus 51: #include "channels.h"
1.1 deraadt 52:
1.25 markus 53: #include "compat.h"
1.45 markus 54: #include "ssh1.h"
1.25 markus 55: #include "ssh2.h"
56:
1.37 markus 57: #include "cipher.h"
1.25 markus 58: #include "kex.h"
1.50 markus 59: #include "mac.h"
1.46 markus 60: #include "log.h"
61: #include "canohost.h"
1.25 markus 62:
63: #ifdef PACKET_DEBUG
64: #define DBG(x) x
65: #else
66: #define DBG(x)
67: #endif
68:
1.16 markus 69: /*
70: * This variable contains the file descriptors used for communicating with
71: * the other side. connection_in is used for reading; connection_out for
72: * writing. These can be the same descriptor, in which case it is assumed to
73: * be a socket.
74: */
1.1 deraadt 75: static int connection_in = -1;
76: static int connection_out = -1;
77:
1.16 markus 78: /*
79: * Cipher type. This value is only used to determine whether to pad the
80: * packets with zeroes or random data.
81: */
1.1 deraadt 82: static int cipher_type = SSH_CIPHER_NONE;
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. */
94: static Buffer input;
95:
96: /* Buffer for raw output data going to the socket. */
97: static Buffer output;
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;
107:
108: /* Flag indicating whether packet compression/decompression is enabled. */
109: static int packet_compression = 0;
110:
1.12 markus 111: /* default maximum packet size */
112: int max_packet_size = 32768;
113:
1.1 deraadt 114: /* Flag indicating whether this module has been initialized. */
115: static int initialized = 0;
116:
117: /* Set to true if the connection is interactive. */
118: static int interactive_mode = 0;
119:
1.25 markus 120: /* True if SSH2 packet format is used */
121: int use_ssh2_packet_format = 0;
122:
123: /* Session key information for Encryption and MAC */
1.57 markus 124: Newkeys *newkeys[MODE_MAX];
1.25 markus 125:
126: void
127: packet_set_ssh2_format(void)
128: {
1.31 markus 129: DBG(debug("use_ssh2_packet_format"));
1.25 markus 130: use_ssh2_packet_format = 1;
1.57 markus 131: newkeys[MODE_IN] = newkeys[MODE_OUT] = NULL;
1.25 markus 132: }
133:
1.16 markus 134: /*
135: * Sets the descriptors used for communication. Disables encryption until
136: * packet_set_encryption_key is called.
137: */
1.2 provos 138: void
139: packet_set_connection(int fd_in, int fd_out)
1.1 deraadt 140: {
1.37 markus 141: Cipher *none = cipher_by_name("none");
142: if (none == NULL)
143: fatal("packet_set_connection: cannot load cipher 'none'");
1.14 markus 144: connection_in = fd_in;
145: connection_out = fd_out;
146: cipher_type = SSH_CIPHER_NONE;
1.40 markus 147: cipher_init(&send_context, none, (u_char *) "", 0, NULL, 0);
148: cipher_init(&receive_context, none, (u_char *) "", 0, NULL, 0);
1.14 markus 149: if (!initialized) {
150: initialized = 1;
151: buffer_init(&input);
152: buffer_init(&output);
153: buffer_init(&outgoing_packet);
154: buffer_init(&incoming_packet);
155: }
156: /* Kludge: arrange the close function to be called from fatal(). */
157: fatal_add_cleanup((void (*) (void *)) packet_close, NULL);
1.1 deraadt 158: }
159:
1.19 markus 160: /* Returns 1 if remote host is connected via socket, 0 if not. */
161:
162: int
163: packet_connection_is_on_socket()
164: {
165: struct sockaddr_storage from, to;
166: socklen_t fromlen, tolen;
167:
168: /* filedescriptors in and out are the same, so it's a socket */
169: if (connection_in == connection_out)
170: return 1;
171: fromlen = sizeof(from);
172: memset(&from, 0, sizeof(from));
1.20 markus 173: if (getpeername(connection_in, (struct sockaddr *)&from, &fromlen) < 0)
1.19 markus 174: return 0;
175: tolen = sizeof(to);
176: memset(&to, 0, sizeof(to));
1.20 markus 177: if (getpeername(connection_out, (struct sockaddr *)&to, &tolen) < 0)
1.19 markus 178: return 0;
179: if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0)
180: return 0;
181: if (from.ss_family != AF_INET && from.ss_family != AF_INET6)
182: return 0;
183: return 1;
184: }
185:
186: /* returns 1 if connection is via ipv4 */
187:
188: int
189: packet_connection_is_ipv4()
190: {
191: struct sockaddr_storage to;
1.21 deraadt 192: socklen_t tolen = sizeof(to);
1.19 markus 193:
194: memset(&to, 0, sizeof(to));
195: if (getsockname(connection_out, (struct sockaddr *)&to, &tolen) < 0)
196: return 0;
197: if (to.ss_family != AF_INET)
198: return 0;
199: return 1;
200: }
201:
1.1 deraadt 202: /* Sets the connection into non-blocking mode. */
203:
1.2 provos 204: void
205: packet_set_nonblocking()
1.1 deraadt 206: {
1.14 markus 207: /* Set the socket into non-blocking mode. */
208: if (fcntl(connection_in, F_SETFL, O_NONBLOCK) < 0)
209: error("fcntl O_NONBLOCK: %.100s", strerror(errno));
210:
211: if (connection_out != connection_in) {
212: if (fcntl(connection_out, F_SETFL, O_NONBLOCK) < 0)
213: error("fcntl O_NONBLOCK: %.100s", strerror(errno));
214: }
1.1 deraadt 215: }
216:
217: /* Returns the socket used for reading. */
218:
1.2 provos 219: int
220: packet_get_connection_in()
1.1 deraadt 221: {
1.14 markus 222: return connection_in;
1.1 deraadt 223: }
224:
225: /* Returns the descriptor used for writing. */
226:
1.2 provos 227: int
228: packet_get_connection_out()
1.1 deraadt 229: {
1.14 markus 230: return connection_out;
1.1 deraadt 231: }
232:
233: /* Closes the connection and clears and frees internal data structures. */
234:
1.2 provos 235: void
236: packet_close()
1.1 deraadt 237: {
1.14 markus 238: if (!initialized)
239: return;
240: initialized = 0;
241: if (connection_in == connection_out) {
242: shutdown(connection_out, SHUT_RDWR);
243: close(connection_out);
244: } else {
245: close(connection_in);
246: close(connection_out);
247: }
248: buffer_free(&input);
249: buffer_free(&output);
250: buffer_free(&outgoing_packet);
251: buffer_free(&incoming_packet);
252: if (packet_compression) {
253: buffer_free(&compression_buffer);
254: buffer_compress_uninit();
255: }
1.1 deraadt 256: }
257:
258: /* Sets remote side protocol flags. */
259:
1.2 provos 260: void
1.40 markus 261: packet_set_protocol_flags(u_int protocol_flags)
1.1 deraadt 262: {
1.14 markus 263: remote_protocol_flags = protocol_flags;
264: channel_set_options((protocol_flags & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) != 0);
1.1 deraadt 265: }
266:
267: /* Returns the remote protocol flags set earlier by the above function. */
268:
1.40 markus 269: u_int
1.2 provos 270: packet_get_protocol_flags()
1.1 deraadt 271: {
1.14 markus 272: return remote_protocol_flags;
1.1 deraadt 273: }
274:
1.16 markus 275: /*
276: * Starts packet compression from the next packet on in both directions.
277: * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip.
278: */
1.1 deraadt 279:
1.25 markus 280: /*** XXXXX todo: kex means re-init */
1.2 provos 281: void
282: packet_start_compression(int level)
1.1 deraadt 283: {
1.14 markus 284: if (packet_compression)
285: fatal("Compression already enabled.");
286: packet_compression = 1;
287: buffer_init(&compression_buffer);
288: buffer_compress_init(level);
1.1 deraadt 289: }
290:
1.16 markus 291: /*
292: * Encrypts the given number of bytes, copying from src to dest. bytes is
293: * known to be a multiple of 8.
294: */
1.1 deraadt 295:
1.2 provos 296: void
1.14 markus 297: packet_encrypt(CipherContext * cc, void *dest, void *src,
1.40 markus 298: u_int bytes)
1.1 deraadt 299: {
1.14 markus 300: cipher_encrypt(cc, dest, src, bytes);
1.1 deraadt 301: }
302:
1.16 markus 303: /*
304: * Decrypts the given number of bytes, copying from src to dest. bytes is
305: * known to be a multiple of 8.
306: */
1.1 deraadt 307:
1.2 provos 308: void
1.40 markus 309: packet_decrypt(CipherContext *context, void *dest, void *src, u_int bytes)
1.1 deraadt 310: {
1.16 markus 311: /*
312: * Cryptographic attack detector for ssh - Modifications for packet.c
313: * (C)1998 CORE-SDI, Buenos Aires Argentina Ariel Futoransky(futo@core-sdi.com)
314: */
1.37 markus 315: if (!compat20 &&
316: context->cipher->number != SSH_CIPHER_NONE &&
317: detect_attack(src, bytes, NULL) == DEATTACK_DETECTED)
1.14 markus 318: packet_disconnect("crc32 compensation attack: network attack detected");
319:
1.37 markus 320: cipher_decrypt(context, dest, src, bytes);
1.1 deraadt 321: }
322:
1.16 markus 323: /*
324: * Causes any further packets to be encrypted using the given key. The same
325: * key is used for both sending and reception. However, both directions are
326: * encrypted independently of each other.
327: */
1.1 deraadt 328:
1.2 provos 329: void
1.40 markus 330: packet_set_encryption_key(const u_char *key, u_int keylen,
1.37 markus 331: int number)
1.1 deraadt 332: {
1.37 markus 333: Cipher *cipher = cipher_by_number(number);
334: if (cipher == NULL)
335: fatal("packet_set_encryption_key: unknown cipher number %d", number);
1.25 markus 336: if (keylen < 20)
1.37 markus 337: fatal("packet_set_encryption_key: keylen too small: %d", keylen);
338: cipher_init(&receive_context, cipher, key, keylen, NULL, 0);
339: cipher_init(&send_context, cipher, key, keylen, NULL, 0);
1.1 deraadt 340: }
341:
342: /* Starts constructing a packet to send. */
343:
1.2 provos 344: void
1.25 markus 345: packet_start1(int type)
1.1 deraadt 346: {
1.14 markus 347: char buf[9];
1.1 deraadt 348:
1.14 markus 349: buffer_clear(&outgoing_packet);
350: memset(buf, 0, 8);
351: buf[8] = type;
352: buffer_append(&outgoing_packet, buf, 9);
1.1 deraadt 353: }
354:
1.25 markus 355: void
356: packet_start2(int type)
357: {
358: char buf[4+1+1];
359:
360: buffer_clear(&outgoing_packet);
361: memset(buf, 0, sizeof buf);
362: /* buf[0..3] = payload_len; */
363: /* buf[4] = pad_len; */
364: buf[5] = type & 0xff;
365: buffer_append(&outgoing_packet, buf, sizeof buf);
366: }
367:
368: void
369: packet_start(int type)
370: {
1.55 deraadt 371: DBG(debug("packet_start[%d]", type));
1.25 markus 372: if (use_ssh2_packet_format)
373: packet_start2(type);
374: else
375: packet_start1(type);
376: }
377:
1.1 deraadt 378: /* Appends a character to the packet data. */
379:
1.2 provos 380: void
381: packet_put_char(int value)
1.1 deraadt 382: {
1.14 markus 383: char ch = value;
384: buffer_append(&outgoing_packet, &ch, 1);
1.1 deraadt 385: }
386:
387: /* Appends an integer to the packet data. */
388:
1.2 provos 389: void
1.40 markus 390: packet_put_int(u_int value)
1.1 deraadt 391: {
1.14 markus 392: buffer_put_int(&outgoing_packet, value);
1.1 deraadt 393: }
394:
395: /* Appends a string to packet data. */
396:
1.2 provos 397: void
1.40 markus 398: packet_put_string(const char *buf, u_int len)
1.1 deraadt 399: {
1.14 markus 400: buffer_put_string(&outgoing_packet, buf, len);
1.1 deraadt 401: }
1.24 markus 402: void
403: packet_put_cstring(const char *str)
404: {
405: buffer_put_string(&outgoing_packet, str, strlen(str));
406: }
407:
408: void
1.40 markus 409: packet_put_raw(const char *buf, u_int len)
1.24 markus 410: {
411: buffer_append(&outgoing_packet, buf, len);
412: }
413:
1.1 deraadt 414:
415: /* Appends an arbitrary precision integer to packet data. */
416:
1.2 provos 417: void
1.14 markus 418: packet_put_bignum(BIGNUM * value)
1.1 deraadt 419: {
1.14 markus 420: buffer_put_bignum(&outgoing_packet, value);
1.1 deraadt 421: }
1.24 markus 422: void
423: packet_put_bignum2(BIGNUM * value)
424: {
425: buffer_put_bignum2(&outgoing_packet, value);
426: }
1.1 deraadt 427:
1.16 markus 428: /*
429: * Finalizes and sends the packet. If the encryption key has been set,
430: * encrypts the packet before sending.
431: */
1.14 markus 432:
1.2 provos 433: void
1.49 itojun 434: packet_send1(void)
1.1 deraadt 435: {
1.14 markus 436: char buf[8], *cp;
437: int i, padding, len;
1.40 markus 438: u_int checksum;
1.14 markus 439: u_int32_t rand = 0;
440:
1.16 markus 441: /*
442: * If using packet compression, compress the payload of the outgoing
443: * packet.
444: */
1.14 markus 445: if (packet_compression) {
446: buffer_clear(&compression_buffer);
447: /* Skip padding. */
448: buffer_consume(&outgoing_packet, 8);
449: /* padding */
450: buffer_append(&compression_buffer, "\0\0\0\0\0\0\0\0", 8);
451: buffer_compress(&outgoing_packet, &compression_buffer);
452: buffer_clear(&outgoing_packet);
453: buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer),
454: buffer_len(&compression_buffer));
455: }
456: /* Compute packet length without padding (add checksum, remove padding). */
457: len = buffer_len(&outgoing_packet) + 4 - 8;
458:
1.32 markus 459: /* Insert padding. Initialized to zero in packet_start1() */
1.14 markus 460: padding = 8 - len % 8;
461: if (cipher_type != SSH_CIPHER_NONE) {
462: cp = buffer_ptr(&outgoing_packet);
463: for (i = 0; i < padding; i++) {
464: if (i % 4 == 0)
465: rand = arc4random();
466: cp[7 - i] = rand & 0xff;
467: rand >>= 8;
468: }
469: }
470: buffer_consume(&outgoing_packet, 8 - padding);
471:
472: /* Add check bytes. */
1.40 markus 473: checksum = ssh_crc32((u_char *) buffer_ptr(&outgoing_packet),
1.34 deraadt 474: buffer_len(&outgoing_packet));
1.14 markus 475: PUT_32BIT(buf, checksum);
476: buffer_append(&outgoing_packet, buf, 4);
1.1 deraadt 477:
478: #ifdef PACKET_DEBUG
1.14 markus 479: fprintf(stderr, "packet_send plain: ");
480: buffer_dump(&outgoing_packet);
1.1 deraadt 481: #endif
482:
1.14 markus 483: /* Append to output. */
484: PUT_32BIT(buf, len);
485: buffer_append(&output, buf, 4);
486: buffer_append_space(&output, &cp, buffer_len(&outgoing_packet));
487: packet_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet),
488: buffer_len(&outgoing_packet));
489:
1.1 deraadt 490: #ifdef PACKET_DEBUG
1.14 markus 491: fprintf(stderr, "encrypted: ");
492: buffer_dump(&output);
1.1 deraadt 493: #endif
494:
1.14 markus 495: buffer_clear(&outgoing_packet);
1.1 deraadt 496:
1.16 markus 497: /*
498: * Note that the packet is now only buffered in output. It won\'t be
499: * actually sent until packet_write_wait or packet_write_poll is
500: * called.
501: */
1.1 deraadt 502: }
503:
1.57 markus 504: void
505: set_newkeys(int mode)
506: {
507: Enc *enc;
508: Mac *mac;
509: Comp *comp;
510: CipherContext *cc;
511:
512: debug("newkeys: mode %d", mode);
513:
514: cc = (mode == MODE_OUT) ? &send_context : &receive_context;
515: if (newkeys[mode] != NULL) {
516: debug("newkeys: rekeying");
1.59 ! markus 517: /* todo: free old keys, reset compression/cipher-ctxt; */
1.57 markus 518: memset(cc, 0, sizeof(*cc));
1.59 ! markus 519: enc = &newkeys[mode]->enc;
! 520: mac = &newkeys[mode]->mac;
! 521: comp = &newkeys[mode]->comp;
! 522: memset(mac->key, 0, mac->key_len);
! 523: xfree(enc->name);
! 524: xfree(enc->iv);
! 525: xfree(enc->key);
! 526: xfree(mac->name);
! 527: xfree(mac->key);
! 528: xfree(comp->name);
1.58 markus 529: xfree(newkeys[mode]);
1.57 markus 530: }
531: newkeys[mode] = kex_get_newkeys(mode);
532: if (newkeys[mode] == NULL)
533: fatal("newkeys: no keys for mode %d", mode);
534: enc = &newkeys[mode]->enc;
535: mac = &newkeys[mode]->mac;
536: comp = &newkeys[mode]->comp;
537: if (mac->md != NULL)
538: mac->enabled = 1;
539: DBG(debug("cipher_init_context: %d", mode));
540: cipher_init(cc, enc->cipher, enc->key, enc->cipher->key_len,
541: enc->iv, enc->cipher->block_size);
1.59 ! markus 542: memset(enc->iv, 0, enc->cipher->block_size);
! 543: memset(enc->key, 0, enc->cipher->key_len);
1.57 markus 544: if (comp->type != 0 && comp->enabled == 0) {
545: comp->enabled = 1;
546: if (! packet_compression)
547: packet_start_compression(6);
548: }
549: }
550:
1.16 markus 551: /*
1.25 markus 552: * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue)
553: */
554: void
1.49 itojun 555: packet_send2(void)
1.25 markus 556: {
1.50 markus 557: static u_int32_t seqnr = 0;
1.40 markus 558: u_char *macbuf = NULL;
1.25 markus 559: char *cp;
1.40 markus 560: u_int packet_length = 0;
561: u_int i, padlen, len;
1.25 markus 562: u_int32_t rand = 0;
563: int type;
564: Enc *enc = NULL;
565: Mac *mac = NULL;
566: Comp *comp = NULL;
567: int block_size;
568:
1.57 markus 569: if (newkeys[MODE_OUT] != NULL) {
570: enc = &newkeys[MODE_OUT]->enc;
571: mac = &newkeys[MODE_OUT]->mac;
572: comp = &newkeys[MODE_OUT]->comp;
1.25 markus 573: }
1.37 markus 574: block_size = enc ? enc->cipher->block_size : 8;
1.25 markus 575:
576: cp = buffer_ptr(&outgoing_packet);
577: type = cp[5] & 0xff;
578:
579: #ifdef PACKET_DEBUG
580: fprintf(stderr, "plain: ");
581: buffer_dump(&outgoing_packet);
582: #endif
583:
584: if (comp && comp->enabled) {
585: len = buffer_len(&outgoing_packet);
586: /* skip header, compress only payload */
587: buffer_consume(&outgoing_packet, 5);
588: buffer_clear(&compression_buffer);
589: buffer_compress(&outgoing_packet, &compression_buffer);
590: buffer_clear(&outgoing_packet);
591: buffer_append(&outgoing_packet, "\0\0\0\0\0", 5);
592: buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer),
593: buffer_len(&compression_buffer));
594: DBG(debug("compression: raw %d compressed %d", len,
595: buffer_len(&outgoing_packet)));
596: }
597:
598: /* sizeof (packet_len + pad_len + payload) */
599: len = buffer_len(&outgoing_packet);
600:
601: /*
602: * calc size of padding, alloc space, get random data,
603: * minimum padding is 4 bytes
604: */
605: padlen = block_size - (len % block_size);
606: if (padlen < 4)
607: padlen += block_size;
608: buffer_append_space(&outgoing_packet, &cp, padlen);
1.38 markus 609: if (enc && enc->cipher->number != SSH_CIPHER_NONE) {
1.32 markus 610: /* random padding */
1.25 markus 611: for (i = 0; i < padlen; i++) {
612: if (i % 4 == 0)
613: rand = arc4random();
614: cp[i] = rand & 0xff;
1.52 markus 615: rand >>= 8;
1.25 markus 616: }
1.32 markus 617: } else {
618: /* clear padding */
619: memset(cp, 0, padlen);
1.25 markus 620: }
621: /* packet_length includes payload, padding and padding length field */
622: packet_length = buffer_len(&outgoing_packet) - 4;
623: cp = buffer_ptr(&outgoing_packet);
624: PUT_32BIT(cp, packet_length);
625: cp[4] = padlen & 0xff;
626: DBG(debug("send: len %d (includes padlen %d)", packet_length+4, padlen));
627:
628: /* compute MAC over seqnr and packet(length fields, payload, padding) */
629: if (mac && mac->enabled) {
1.50 markus 630: macbuf = mac_compute(mac, seqnr,
1.40 markus 631: (u_char *) buffer_ptr(&outgoing_packet),
1.50 markus 632: buffer_len(&outgoing_packet));
1.36 markus 633: DBG(debug("done calc MAC out #%d", seqnr));
1.25 markus 634: }
635: /* encrypt packet and append to output buffer. */
636: buffer_append_space(&output, &cp, buffer_len(&outgoing_packet));
637: packet_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet),
638: buffer_len(&outgoing_packet));
639: /* append unencrypted MAC */
640: if (mac && mac->enabled)
641: buffer_append(&output, (char *)macbuf, mac->mac_len);
642: #ifdef PACKET_DEBUG
643: fprintf(stderr, "encrypted: ");
644: buffer_dump(&output);
645: #endif
1.29 markus 646: /* increment sequence number for outgoing packets */
647: if (++seqnr == 0)
648: log("outgoing seqnr wraps around");
1.25 markus 649: buffer_clear(&outgoing_packet);
650:
1.57 markus 651: if (type == SSH2_MSG_NEWKEYS)
652: set_newkeys(MODE_OUT);
1.25 markus 653: }
654:
655: void
656: packet_send()
657: {
658: if (use_ssh2_packet_format)
659: packet_send2();
660: else
661: packet_send1();
662: DBG(debug("packet_send done"));
663: }
664:
665: /*
1.16 markus 666: * Waits until a packet has been received, and returns its type. Note that
667: * no other data is processed until this returns, so this function should not
668: * be used during the interactive session.
669: */
1.1 deraadt 670:
1.2 provos 671: int
672: packet_read(int *payload_len_ptr)
1.1 deraadt 673: {
1.14 markus 674: int type, len;
1.56 millert 675: fd_set *setp;
1.14 markus 676: char buf[8192];
1.25 markus 677: DBG(debug("packet_read()"));
1.14 markus 678:
1.56 millert 679: setp = (fd_set *)xmalloc(howmany(connection_in+1, NFDBITS) *
680: sizeof(fd_mask));
681:
1.14 markus 682: /* Since we are blocking, ensure that all written packets have been sent. */
683: packet_write_wait();
684:
685: /* Stay in the loop until we have received a complete packet. */
686: for (;;) {
687: /* Try to read a packet from the buffer. */
688: type = packet_read_poll(payload_len_ptr);
1.32 markus 689: if (!use_ssh2_packet_format && (
690: type == SSH_SMSG_SUCCESS
1.14 markus 691: || type == SSH_SMSG_FAILURE
692: || type == SSH_CMSG_EOF
1.32 markus 693: || type == SSH_CMSG_EXIT_CONFIRMATION))
1.14 markus 694: packet_integrity_check(*payload_len_ptr, 0, type);
695: /* If we got a packet, return it. */
1.56 millert 696: if (type != SSH_MSG_NONE) {
697: xfree(setp);
1.14 markus 698: return type;
1.56 millert 699: }
1.16 markus 700: /*
701: * Otherwise, wait for some data to arrive, add it to the
702: * buffer, and try again.
703: */
1.56 millert 704: memset(setp, 0, howmany(connection_in + 1, NFDBITS) *
705: sizeof(fd_mask));
706: FD_SET(connection_in, setp);
1.16 markus 707:
1.14 markus 708: /* Wait for some data to arrive. */
1.56 millert 709: while (select(connection_in + 1, setp, NULL, NULL, NULL) == -1 &&
1.51 deraadt 710: (errno == EAGAIN || errno == EINTR))
711: ;
1.16 markus 712:
1.14 markus 713: /* Read data from the socket. */
714: len = read(connection_in, buf, sizeof(buf));
1.18 markus 715: if (len == 0) {
716: log("Connection closed by %.200s", get_remote_ipaddr());
717: fatal_cleanup();
718: }
1.14 markus 719: if (len < 0)
720: fatal("Read from socket failed: %.100s", strerror(errno));
721: /* Append it to the buffer. */
722: packet_process_incoming(buf, len);
723: }
724: /* NOTREACHED */
1.1 deraadt 725: }
726:
1.16 markus 727: /*
728: * Waits until a packet has been received, verifies that its type matches
729: * that given, and gives a fatal error and exits if there is a mismatch.
730: */
1.1 deraadt 731:
1.2 provos 732: void
733: packet_read_expect(int *payload_len_ptr, int expected_type)
1.1 deraadt 734: {
1.14 markus 735: int type;
1.1 deraadt 736:
1.14 markus 737: type = packet_read(payload_len_ptr);
738: if (type != expected_type)
739: packet_disconnect("Protocol error: expected packet type %d, got %d",
1.25 markus 740: expected_type, type);
1.1 deraadt 741: }
742:
743: /* Checks if a full packet is available in the data received so far via
1.14 markus 744: * packet_process_incoming. If so, reads the packet; otherwise returns
745: * SSH_MSG_NONE. This does not wait for data from the connection.
746: *
747: * SSH_MSG_DISCONNECT is handled specially here. Also,
748: * SSH_MSG_IGNORE messages are skipped by this function and are never returned
749: * to higher levels.
750: *
751: * The returned payload_len does include space consumed by:
752: * Packet length
753: * Padding
754: * Packet type
755: * Check bytes
756: */
1.1 deraadt 757:
1.2 provos 758: int
1.25 markus 759: packet_read_poll1(int *payload_len_ptr)
1.1 deraadt 760: {
1.40 markus 761: u_int len, padded_len;
762: u_char *ucp;
1.25 markus 763: char buf[8], *cp;
1.40 markus 764: u_int checksum, stored_checksum;
1.14 markus 765:
766: /* Check if input size is less than minimum packet size. */
767: if (buffer_len(&input) < 4 + 8)
768: return SSH_MSG_NONE;
769: /* Get length of incoming packet. */
1.40 markus 770: ucp = (u_char *) buffer_ptr(&input);
1.14 markus 771: len = GET_32BIT(ucp);
772: if (len < 1 + 2 + 2 || len > 256 * 1024)
773: packet_disconnect("Bad packet length %d.", len);
774: padded_len = (len + 8) & ~7;
775:
776: /* Check if the packet has been entirely received. */
777: if (buffer_len(&input) < 4 + padded_len)
778: return SSH_MSG_NONE;
779:
780: /* The entire packet is in buffer. */
781:
782: /* Consume packet length. */
783: buffer_consume(&input, 4);
784:
785: /* Copy data to incoming_packet. */
786: buffer_clear(&incoming_packet);
787: buffer_append_space(&incoming_packet, &cp, padded_len);
788: packet_decrypt(&receive_context, cp, buffer_ptr(&input), padded_len);
789: buffer_consume(&input, padded_len);
1.1 deraadt 790:
791: #ifdef PACKET_DEBUG
1.14 markus 792: fprintf(stderr, "read_poll plain: ");
793: buffer_dump(&incoming_packet);
1.1 deraadt 794: #endif
795:
1.14 markus 796: /* Compute packet checksum. */
1.40 markus 797: checksum = ssh_crc32((u_char *) buffer_ptr(&incoming_packet),
1.25 markus 798: buffer_len(&incoming_packet) - 4);
1.14 markus 799:
800: /* Skip padding. */
801: buffer_consume(&incoming_packet, 8 - len % 8);
802:
803: /* Test check bytes. */
804:
805: if (len != buffer_len(&incoming_packet))
806: packet_disconnect("packet_read_poll: len %d != buffer_len %d.",
1.25 markus 807: len, buffer_len(&incoming_packet));
1.14 markus 808:
1.40 markus 809: ucp = (u_char *) buffer_ptr(&incoming_packet) + len - 4;
1.14 markus 810: stored_checksum = GET_32BIT(ucp);
811: if (checksum != stored_checksum)
812: packet_disconnect("Corrupted check bytes on input.");
813: buffer_consume_end(&incoming_packet, 4);
814:
815: /* If using packet compression, decompress the packet. */
816: if (packet_compression) {
817: buffer_clear(&compression_buffer);
818: buffer_uncompress(&incoming_packet, &compression_buffer);
819: buffer_clear(&incoming_packet);
820: buffer_append(&incoming_packet, buffer_ptr(&compression_buffer),
1.25 markus 821: buffer_len(&compression_buffer));
1.14 markus 822: }
823: /* Get packet type. */
824: buffer_get(&incoming_packet, &buf[0], 1);
825:
826: /* Return length of payload (without type field). */
827: *payload_len_ptr = buffer_len(&incoming_packet);
828:
829: /* Return type. */
1.40 markus 830: return (u_char) buf[0];
1.1 deraadt 831: }
1.14 markus 832:
1.25 markus 833: int
834: packet_read_poll2(int *payload_len_ptr)
835: {
1.50 markus 836: static u_int32_t seqnr = 0;
837: static u_int packet_length = 0;
1.40 markus 838: u_int padlen, need;
839: u_char buf[8], *macbuf;
840: u_char *ucp;
1.25 markus 841: char *cp;
842: int type;
843: int maclen, block_size;
844: Enc *enc = NULL;
845: Mac *mac = NULL;
846: Comp *comp = NULL;
847:
1.57 markus 848: if (newkeys[MODE_IN] != NULL) {
849: enc = &newkeys[MODE_IN]->enc;
850: mac = &newkeys[MODE_IN]->mac;
851: comp = &newkeys[MODE_IN]->comp;
1.25 markus 852: }
853: maclen = mac && mac->enabled ? mac->mac_len : 0;
1.37 markus 854: block_size = enc ? enc->cipher->block_size : 8;
1.25 markus 855:
856: if (packet_length == 0) {
857: /*
858: * check if input size is less than the cipher block size,
859: * decrypt first block and extract length of incoming packet
860: */
861: if (buffer_len(&input) < block_size)
862: return SSH_MSG_NONE;
863: buffer_clear(&incoming_packet);
864: buffer_append_space(&incoming_packet, &cp, block_size);
865: packet_decrypt(&receive_context, cp, buffer_ptr(&input),
866: block_size);
1.40 markus 867: ucp = (u_char *) buffer_ptr(&incoming_packet);
1.25 markus 868: packet_length = GET_32BIT(ucp);
869: if (packet_length < 1 + 4 || packet_length > 256 * 1024) {
870: buffer_dump(&incoming_packet);
871: packet_disconnect("Bad packet length %d.", packet_length);
872: }
873: DBG(debug("input: packet len %d", packet_length+4));
874: buffer_consume(&input, block_size);
875: }
876: /* we have a partial packet of block_size bytes */
877: need = 4 + packet_length - block_size;
878: DBG(debug("partial packet %d, need %d, maclen %d", block_size,
879: need, maclen));
880: if (need % block_size != 0)
881: fatal("padding error: need %d block %d mod %d",
882: need, block_size, need % block_size);
883: /*
884: * check if the entire packet has been received and
885: * decrypt into incoming_packet
886: */
887: if (buffer_len(&input) < need + maclen)
888: return SSH_MSG_NONE;
889: #ifdef PACKET_DEBUG
890: fprintf(stderr, "read_poll enc/full: ");
891: buffer_dump(&input);
892: #endif
893: buffer_append_space(&incoming_packet, &cp, need);
894: packet_decrypt(&receive_context, cp, buffer_ptr(&input), need);
895: buffer_consume(&input, need);
896: /*
897: * compute MAC over seqnr and packet,
898: * increment sequence number for incoming packet
899: */
1.29 markus 900: if (mac && mac->enabled) {
1.50 markus 901: macbuf = mac_compute(mac, seqnr,
1.40 markus 902: (u_char *) buffer_ptr(&incoming_packet),
1.50 markus 903: buffer_len(&incoming_packet));
1.25 markus 904: if (memcmp(macbuf, buffer_ptr(&input), mac->mac_len) != 0)
1.36 markus 905: packet_disconnect("Corrupted MAC on input.");
906: DBG(debug("MAC #%d ok", seqnr));
1.25 markus 907: buffer_consume(&input, mac->mac_len);
908: }
1.29 markus 909: if (++seqnr == 0)
910: log("incoming seqnr wraps around");
1.25 markus 911:
912: /* get padlen */
913: cp = buffer_ptr(&incoming_packet) + 4;
914: padlen = *cp & 0xff;
915: DBG(debug("input: padlen %d", padlen));
916: if (padlen < 4)
917: packet_disconnect("Corrupted padlen %d on input.", padlen);
918:
919: /* skip packet size + padlen, discard padding */
920: buffer_consume(&incoming_packet, 4 + 1);
921: buffer_consume_end(&incoming_packet, padlen);
922:
923: DBG(debug("input: len before de-compress %d", buffer_len(&incoming_packet)));
924: if (comp && comp->enabled) {
925: buffer_clear(&compression_buffer);
926: buffer_uncompress(&incoming_packet, &compression_buffer);
927: buffer_clear(&incoming_packet);
928: buffer_append(&incoming_packet, buffer_ptr(&compression_buffer),
929: buffer_len(&compression_buffer));
930: DBG(debug("input: len after de-compress %d", buffer_len(&incoming_packet)));
931: }
932: /*
933: * get packet type, implies consume.
934: * return length of payload (without type field)
935: */
936: buffer_get(&incoming_packet, (char *)&buf[0], 1);
937: *payload_len_ptr = buffer_len(&incoming_packet);
938:
939: /* reset for next packet */
940: packet_length = 0;
941:
942: /* extract packet type */
1.40 markus 943: type = (u_char)buf[0];
1.25 markus 944:
1.57 markus 945: if (type == SSH2_MSG_NEWKEYS)
946: set_newkeys(MODE_IN);
1.25 markus 947:
948: #ifdef PACKET_DEBUG
1.55 deraadt 949: fprintf(stderr, "read/plain[%d]:\r\n", type);
1.25 markus 950: buffer_dump(&incoming_packet);
951: #endif
1.40 markus 952: return (u_char)type;
1.25 markus 953: }
954:
955: int
956: packet_read_poll(int *payload_len_ptr)
957: {
958: char *msg;
959: for (;;) {
960: int type = use_ssh2_packet_format ?
961: packet_read_poll2(payload_len_ptr):
962: packet_read_poll1(payload_len_ptr);
963:
964: if(compat20) {
965: int reason;
966: if (type != 0)
967: DBG(debug("received packet type %d", type));
968: switch(type) {
969: case SSH2_MSG_IGNORE:
970: break;
971: case SSH2_MSG_DEBUG:
972: packet_get_char();
973: msg = packet_get_string(NULL);
974: debug("Remote: %.900s", msg);
975: xfree(msg);
976: msg = packet_get_string(NULL);
977: xfree(msg);
978: break;
979: case SSH2_MSG_DISCONNECT:
980: reason = packet_get_int();
981: msg = packet_get_string(NULL);
1.41 markus 982: log("Received disconnect from %s: %d: %.400s", get_remote_ipaddr(),
983: reason, msg);
1.25 markus 984: xfree(msg);
985: fatal_cleanup();
986: break;
987: default:
988: return type;
989: break;
1.48 stevesk 990: }
1.25 markus 991: } else {
992: switch(type) {
993: case SSH_MSG_IGNORE:
994: break;
995: case SSH_MSG_DEBUG:
996: msg = packet_get_string(NULL);
997: debug("Remote: %.900s", msg);
998: xfree(msg);
999: break;
1000: case SSH_MSG_DISCONNECT:
1001: msg = packet_get_string(NULL);
1.41 markus 1002: log("Received disconnect from %s: %.400s", get_remote_ipaddr(),
1003: msg);
1.25 markus 1004: fatal_cleanup();
1005: xfree(msg);
1006: break;
1007: default:
1008: if (type != 0)
1009: DBG(debug("received packet type %d", type));
1010: return type;
1011: break;
1.48 stevesk 1012: }
1.25 markus 1013: }
1014: }
1015: }
1016:
1.16 markus 1017: /*
1018: * Buffers the given amount of input characters. This is intended to be used
1019: * together with packet_read_poll.
1020: */
1.1 deraadt 1021:
1.2 provos 1022: void
1.40 markus 1023: packet_process_incoming(const char *buf, u_int len)
1.1 deraadt 1024: {
1.14 markus 1025: buffer_append(&input, buf, len);
1.1 deraadt 1026: }
1027:
1028: /* Returns a character from the packet. */
1029:
1.40 markus 1030: u_int
1.2 provos 1031: packet_get_char()
1.1 deraadt 1032: {
1.14 markus 1033: char ch;
1034: buffer_get(&incoming_packet, &ch, 1);
1.40 markus 1035: return (u_char) ch;
1.1 deraadt 1036: }
1037:
1038: /* Returns an integer from the packet data. */
1039:
1.40 markus 1040: u_int
1.2 provos 1041: packet_get_int()
1.1 deraadt 1042: {
1.14 markus 1043: return buffer_get_int(&incoming_packet);
1.1 deraadt 1044: }
1045:
1.16 markus 1046: /*
1047: * Returns an arbitrary precision integer from the packet data. The integer
1048: * must have been initialized before this call.
1049: */
1.1 deraadt 1050:
1.2 provos 1051: void
1.14 markus 1052: packet_get_bignum(BIGNUM * value, int *length_ptr)
1.1 deraadt 1053: {
1.14 markus 1054: *length_ptr = buffer_get_bignum(&incoming_packet, value);
1.24 markus 1055: }
1056:
1057: void
1058: packet_get_bignum2(BIGNUM * value, int *length_ptr)
1059: {
1060: *length_ptr = buffer_get_bignum2(&incoming_packet, value);
1061: }
1062:
1063: char *
1064: packet_get_raw(int *length_ptr)
1065: {
1066: int bytes = buffer_len(&incoming_packet);
1067: if (length_ptr != NULL)
1068: *length_ptr = bytes;
1069: return buffer_ptr(&incoming_packet);
1.28 markus 1070: }
1071:
1072: int
1073: packet_remaining(void)
1074: {
1075: return buffer_len(&incoming_packet);
1.1 deraadt 1076: }
1077:
1.16 markus 1078: /*
1079: * Returns a string from the packet data. The string is allocated using
1080: * xmalloc; it is the responsibility of the calling program to free it when
1081: * no longer needed. The length_ptr argument may be NULL, or point to an
1082: * integer into which the length of the string is stored.
1083: */
1.1 deraadt 1084:
1.16 markus 1085: char *
1.40 markus 1086: packet_get_string(u_int *length_ptr)
1.1 deraadt 1087: {
1.14 markus 1088: return buffer_get_string(&incoming_packet, length_ptr);
1.1 deraadt 1089: }
1090:
1.16 markus 1091: /*
1092: * Sends a diagnostic message from the server to the client. This message
1093: * can be sent at any time (but not while constructing another message). The
1094: * message is printed immediately, but only if the client is being executed
1095: * in verbose mode. These messages are primarily intended to ease debugging
1096: * authentication problems. The length of the formatted message must not
1097: * exceed 1024 bytes. This will automatically call packet_write_wait.
1098: */
1.1 deraadt 1099:
1.2 provos 1100: void
1.14 markus 1101: packet_send_debug(const char *fmt,...)
1.1 deraadt 1102: {
1.14 markus 1103: char buf[1024];
1104: va_list args;
1.39 markus 1105:
1106: if (compat20 && (datafellows & SSH_BUG_DEBUG))
1107: return;
1.14 markus 1108:
1109: va_start(args, fmt);
1110: vsnprintf(buf, sizeof(buf), fmt, args);
1111: va_end(args);
1112:
1.30 markus 1113: if (compat20) {
1114: packet_start(SSH2_MSG_DEBUG);
1115: packet_put_char(0); /* bool: always display */
1116: packet_put_cstring(buf);
1117: packet_put_cstring("");
1118: } else {
1119: packet_start(SSH_MSG_DEBUG);
1120: packet_put_cstring(buf);
1121: }
1.14 markus 1122: packet_send();
1123: packet_write_wait();
1.1 deraadt 1124: }
1125:
1.16 markus 1126: /*
1127: * Logs the error plus constructs and sends a disconnect packet, closes the
1128: * connection, and exits. This function never returns. The error message
1129: * should not contain a newline. The length of the formatted message must
1130: * not exceed 1024 bytes.
1131: */
1.1 deraadt 1132:
1.2 provos 1133: void
1.14 markus 1134: packet_disconnect(const char *fmt,...)
1.1 deraadt 1135: {
1.14 markus 1136: char buf[1024];
1137: va_list args;
1138: static int disconnecting = 0;
1139: if (disconnecting) /* Guard against recursive invocations. */
1140: fatal("packet_disconnect called recursively.");
1141: disconnecting = 1;
1142:
1.16 markus 1143: /*
1144: * Format the message. Note that the caller must make sure the
1145: * message is of limited size.
1146: */
1.14 markus 1147: va_start(args, fmt);
1148: vsnprintf(buf, sizeof(buf), fmt, args);
1149: va_end(args);
1150:
1151: /* Send the disconnect message to the other side, and wait for it to get sent. */
1.25 markus 1152: if (compat20) {
1153: packet_start(SSH2_MSG_DISCONNECT);
1154: packet_put_int(SSH2_DISCONNECT_PROTOCOL_ERROR);
1155: packet_put_cstring(buf);
1156: packet_put_cstring("");
1157: } else {
1158: packet_start(SSH_MSG_DISCONNECT);
1159: packet_put_string(buf, strlen(buf));
1160: }
1.14 markus 1161: packet_send();
1162: packet_write_wait();
1163:
1164: /* Stop listening for connections. */
1165: channel_stop_listening();
1166:
1167: /* Close the connection. */
1168: packet_close();
1.1 deraadt 1169:
1.14 markus 1170: /* Display the error locally and exit. */
1.17 markus 1171: log("Disconnecting: %.100s", buf);
1172: fatal_cleanup();
1.1 deraadt 1173: }
1174:
1.16 markus 1175: /* Checks if there is any buffered output, and tries to write some of the output. */
1.1 deraadt 1176:
1.2 provos 1177: void
1178: packet_write_poll()
1.1 deraadt 1179: {
1.14 markus 1180: int len = buffer_len(&output);
1181: if (len > 0) {
1182: len = write(connection_out, buffer_ptr(&output), len);
1183: if (len <= 0) {
1184: if (errno == EAGAIN)
1185: return;
1186: else
1187: fatal("Write failed: %.100s", strerror(errno));
1188: }
1189: buffer_consume(&output, len);
1190: }
1.1 deraadt 1191: }
1192:
1.16 markus 1193: /*
1194: * Calls packet_write_poll repeatedly until all pending output data has been
1195: * written.
1196: */
1.1 deraadt 1197:
1.2 provos 1198: void
1199: packet_write_wait()
1.1 deraadt 1200: {
1.56 millert 1201: fd_set *setp;
1202:
1203: setp = (fd_set *)xmalloc(howmany(connection_out + 1, NFDBITS) *
1204: sizeof(fd_mask));
1.14 markus 1205: packet_write_poll();
1206: while (packet_have_data_to_write()) {
1.56 millert 1207: memset(setp, 0, howmany(connection_out + 1, NFDBITS) *
1208: sizeof(fd_mask));
1209: FD_SET(connection_out, setp);
1210: while (select(connection_out + 1, NULL, setp, NULL, NULL) == -1 &&
1.51 deraadt 1211: (errno == EAGAIN || errno == EINTR))
1212: ;
1.14 markus 1213: packet_write_poll();
1214: }
1.56 millert 1215: xfree(setp);
1.1 deraadt 1216: }
1217:
1218: /* Returns true if there is buffered data to write to the connection. */
1219:
1.2 provos 1220: int
1221: packet_have_data_to_write()
1.1 deraadt 1222: {
1.14 markus 1223: return buffer_len(&output) != 0;
1.1 deraadt 1224: }
1225:
1226: /* Returns true if there is not too much data to write to the connection. */
1227:
1.2 provos 1228: int
1229: packet_not_very_much_data_to_write()
1.1 deraadt 1230: {
1.14 markus 1231: if (interactive_mode)
1232: return buffer_len(&output) < 16384;
1233: else
1234: return buffer_len(&output) < 128 * 1024;
1.1 deraadt 1235: }
1236:
1237: /* Informs that the current session is interactive. Sets IP flags for that. */
1238:
1.2 provos 1239: void
1.43 markus 1240: packet_set_interactive(int interactive)
1.1 deraadt 1241: {
1.43 markus 1242: static int called = 0;
1.44 markus 1243: int lowdelay = IPTOS_LOWDELAY;
1244: int throughput = IPTOS_THROUGHPUT;
1245: int on = 1;
1246:
1.43 markus 1247: if (called)
1248: return;
1249: called = 1;
1.1 deraadt 1250:
1.14 markus 1251: /* Record that we are in interactive mode. */
1252: interactive_mode = interactive;
1.1 deraadt 1253:
1.19 markus 1254: /* Only set socket options if using a socket. */
1255: if (!packet_connection_is_on_socket())
1.14 markus 1256: return;
1.19 markus 1257: /*
1.42 markus 1258: * IPTOS_LOWDELAY and IPTOS_THROUGHPUT are IPv4 only
1.19 markus 1259: */
1.14 markus 1260: if (interactive) {
1.16 markus 1261: /*
1262: * Set IP options for an interactive connection. Use
1263: * IPTOS_LOWDELAY and TCP_NODELAY.
1264: */
1.42 markus 1265: if (packet_connection_is_ipv4()) {
1266: if (setsockopt(connection_in, IPPROTO_IP, IP_TOS,
1267: (void *) &lowdelay, sizeof(lowdelay)) < 0)
1268: error("setsockopt IPTOS_LOWDELAY: %.100s",
1269: strerror(errno));
1270: }
1.14 markus 1271: if (setsockopt(connection_in, IPPROTO_TCP, TCP_NODELAY, (void *) &on,
1.19 markus 1272: sizeof(on)) < 0)
1.14 markus 1273: error("setsockopt TCP_NODELAY: %.100s", strerror(errno));
1.42 markus 1274: } else if (packet_connection_is_ipv4()) {
1.16 markus 1275: /*
1276: * Set IP options for a non-interactive connection. Use
1277: * IPTOS_THROUGHPUT.
1278: */
1.14 markus 1279: if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, (void *) &throughput,
1.19 markus 1280: sizeof(throughput)) < 0)
1.14 markus 1281: error("setsockopt IPTOS_THROUGHPUT: %.100s", strerror(errno));
1282: }
1.1 deraadt 1283: }
1284:
1285: /* Returns true if the current connection is interactive. */
1286:
1.2 provos 1287: int
1288: packet_is_interactive()
1.1 deraadt 1289: {
1.14 markus 1290: return interactive_mode;
1.12 markus 1291: }
1292:
1293: int
1294: packet_set_maxsize(int s)
1295: {
1.14 markus 1296: static int called = 0;
1297: if (called) {
1.25 markus 1298: log("packet_set_maxsize: called twice: old %d new %d",
1299: max_packet_size, s);
1.14 markus 1300: return -1;
1301: }
1302: if (s < 4 * 1024 || s > 1024 * 1024) {
1303: log("packet_set_maxsize: bad size %d", s);
1304: return -1;
1305: }
1306: log("packet_set_maxsize: setting to %d", s);
1307: max_packet_size = s;
1308: return s;
1.53 markus 1309: }
1310:
1311: /*
1312: * 9.2. Ignored Data Message
1313: *
1314: * byte SSH_MSG_IGNORE
1315: * string data
1316: *
1317: * All implementations MUST understand (and ignore) this message at any
1318: * time (after receiving the protocol version). No implementation is
1319: * required to send them. This message can be used as an additional
1320: * protection measure against advanced traffic analysis techniques.
1321: */
1322: /* size of current + ignore message should be n*sumlen bytes (w/o mac) */
1323: void
1324: packet_inject_ignore(int sumlen)
1325: {
1.54 markus 1326: int blocksize, padlen, have, need, nb, mini, nbytes;
1.53 markus 1327: Enc *enc = NULL;
1328:
1329: if (use_ssh2_packet_format == 0)
1330: return;
1331:
1332: have = buffer_len(&outgoing_packet);
1333: debug2("packet_inject_ignore: current %d", have);
1.57 markus 1334: if (newkeys[MODE_OUT] != NULL)
1335: enc = &newkeys[MODE_OUT]->enc;
1.53 markus 1336: blocksize = enc ? enc->cipher->block_size : 8;
1337: padlen = blocksize - (have % blocksize);
1338: if (padlen < 4)
1339: padlen += blocksize;
1340: have += padlen;
1341: have /= blocksize; /* # of blocks for current message */
1342:
1343: nb = roundup(sumlen, blocksize) / blocksize; /* blocks for both */
1344: mini = roundup(5+1+4+4, blocksize) / blocksize; /* minsize ignore msg */
1345: need = nb - (have % nb); /* blocks for ignore */
1346: if (need <= mini)
1347: need += nb;
1348: nbytes = (need - mini) * blocksize; /* size of ignore payload */
1349: debug2("packet_inject_ignore: block %d have %d nb %d mini %d need %d",
1350: blocksize, have, nb, mini, need);
1351:
1352: /* enqueue current message and append a ignore message */
1353: packet_send();
1.54 markus 1354: packet_send_ignore(nbytes);
1355: }
1356:
1357: void
1358: packet_send_ignore(int nbytes)
1359: {
1360: u_int32_t rand = 0;
1361: int i;
1362:
1363: packet_start(compat20 ? SSH2_MSG_IGNORE : SSH_MSG_IGNORE);
1.53 markus 1364: packet_put_int(nbytes);
1365: for(i = 0; i < nbytes; i++) {
1366: if (i % 4 == 0)
1367: rand = arc4random();
1368: packet_put_char(rand & 0xff);
1369: rand >>= 8;
1370: }
1.1 deraadt 1371: }
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