Annotation of src/usr.bin/ssh/packet.c, Revision 1.58
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"
1.58 ! markus 40: RCSID("$OpenBSD: packet.c,v 1.57 2001/04/03 23:32:12 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: clear_enc_keys(Enc *enc, int len)
128: {
129: memset(enc->iv, 0, len);
130: memset(enc->key, 0, len);
131: xfree(enc->iv);
132: xfree(enc->key);
133: enc->iv = NULL;
134: enc->key = NULL;
135: }
136: void
137: packet_set_ssh2_format(void)
138: {
1.31 markus 139: DBG(debug("use_ssh2_packet_format"));
1.25 markus 140: use_ssh2_packet_format = 1;
1.57 markus 141: newkeys[MODE_IN] = newkeys[MODE_OUT] = NULL;
1.25 markus 142: }
143:
1.16 markus 144: /*
145: * Sets the descriptors used for communication. Disables encryption until
146: * packet_set_encryption_key is called.
147: */
1.2 provos 148: void
149: packet_set_connection(int fd_in, int fd_out)
1.1 deraadt 150: {
1.37 markus 151: Cipher *none = cipher_by_name("none");
152: if (none == NULL)
153: fatal("packet_set_connection: cannot load cipher 'none'");
1.14 markus 154: connection_in = fd_in;
155: connection_out = fd_out;
156: cipher_type = SSH_CIPHER_NONE;
1.40 markus 157: cipher_init(&send_context, none, (u_char *) "", 0, NULL, 0);
158: cipher_init(&receive_context, none, (u_char *) "", 0, NULL, 0);
1.14 markus 159: if (!initialized) {
160: initialized = 1;
161: buffer_init(&input);
162: buffer_init(&output);
163: buffer_init(&outgoing_packet);
164: buffer_init(&incoming_packet);
165: }
166: /* Kludge: arrange the close function to be called from fatal(). */
167: fatal_add_cleanup((void (*) (void *)) packet_close, NULL);
1.1 deraadt 168: }
169:
1.19 markus 170: /* Returns 1 if remote host is connected via socket, 0 if not. */
171:
172: int
173: packet_connection_is_on_socket()
174: {
175: struct sockaddr_storage from, to;
176: socklen_t fromlen, tolen;
177:
178: /* filedescriptors in and out are the same, so it's a socket */
179: if (connection_in == connection_out)
180: return 1;
181: fromlen = sizeof(from);
182: memset(&from, 0, sizeof(from));
1.20 markus 183: if (getpeername(connection_in, (struct sockaddr *)&from, &fromlen) < 0)
1.19 markus 184: return 0;
185: tolen = sizeof(to);
186: memset(&to, 0, sizeof(to));
1.20 markus 187: if (getpeername(connection_out, (struct sockaddr *)&to, &tolen) < 0)
1.19 markus 188: return 0;
189: if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0)
190: return 0;
191: if (from.ss_family != AF_INET && from.ss_family != AF_INET6)
192: return 0;
193: return 1;
194: }
195:
196: /* returns 1 if connection is via ipv4 */
197:
198: int
199: packet_connection_is_ipv4()
200: {
201: struct sockaddr_storage to;
1.21 deraadt 202: socklen_t tolen = sizeof(to);
1.19 markus 203:
204: memset(&to, 0, sizeof(to));
205: if (getsockname(connection_out, (struct sockaddr *)&to, &tolen) < 0)
206: return 0;
207: if (to.ss_family != AF_INET)
208: return 0;
209: return 1;
210: }
211:
1.1 deraadt 212: /* Sets the connection into non-blocking mode. */
213:
1.2 provos 214: void
215: packet_set_nonblocking()
1.1 deraadt 216: {
1.14 markus 217: /* Set the socket into non-blocking mode. */
218: if (fcntl(connection_in, F_SETFL, O_NONBLOCK) < 0)
219: error("fcntl O_NONBLOCK: %.100s", strerror(errno));
220:
221: if (connection_out != connection_in) {
222: if (fcntl(connection_out, F_SETFL, O_NONBLOCK) < 0)
223: error("fcntl O_NONBLOCK: %.100s", strerror(errno));
224: }
1.1 deraadt 225: }
226:
227: /* Returns the socket used for reading. */
228:
1.2 provos 229: int
230: packet_get_connection_in()
1.1 deraadt 231: {
1.14 markus 232: return connection_in;
1.1 deraadt 233: }
234:
235: /* Returns the descriptor used for writing. */
236:
1.2 provos 237: int
238: packet_get_connection_out()
1.1 deraadt 239: {
1.14 markus 240: return connection_out;
1.1 deraadt 241: }
242:
243: /* Closes the connection and clears and frees internal data structures. */
244:
1.2 provos 245: void
246: packet_close()
1.1 deraadt 247: {
1.14 markus 248: if (!initialized)
249: return;
250: initialized = 0;
251: if (connection_in == connection_out) {
252: shutdown(connection_out, SHUT_RDWR);
253: close(connection_out);
254: } else {
255: close(connection_in);
256: close(connection_out);
257: }
258: buffer_free(&input);
259: buffer_free(&output);
260: buffer_free(&outgoing_packet);
261: buffer_free(&incoming_packet);
262: if (packet_compression) {
263: buffer_free(&compression_buffer);
264: buffer_compress_uninit();
265: }
1.1 deraadt 266: }
267:
268: /* Sets remote side protocol flags. */
269:
1.2 provos 270: void
1.40 markus 271: packet_set_protocol_flags(u_int protocol_flags)
1.1 deraadt 272: {
1.14 markus 273: remote_protocol_flags = protocol_flags;
274: channel_set_options((protocol_flags & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) != 0);
1.1 deraadt 275: }
276:
277: /* Returns the remote protocol flags set earlier by the above function. */
278:
1.40 markus 279: u_int
1.2 provos 280: packet_get_protocol_flags()
1.1 deraadt 281: {
1.14 markus 282: return remote_protocol_flags;
1.1 deraadt 283: }
284:
1.16 markus 285: /*
286: * Starts packet compression from the next packet on in both directions.
287: * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip.
288: */
1.1 deraadt 289:
1.25 markus 290: /*** XXXXX todo: kex means re-init */
1.2 provos 291: void
292: packet_start_compression(int level)
1.1 deraadt 293: {
1.14 markus 294: if (packet_compression)
295: fatal("Compression already enabled.");
296: packet_compression = 1;
297: buffer_init(&compression_buffer);
298: buffer_compress_init(level);
1.1 deraadt 299: }
300:
1.16 markus 301: /*
302: * Encrypts the given number of bytes, copying from src to dest. bytes is
303: * known to be a multiple of 8.
304: */
1.1 deraadt 305:
1.2 provos 306: void
1.14 markus 307: packet_encrypt(CipherContext * cc, void *dest, void *src,
1.40 markus 308: u_int bytes)
1.1 deraadt 309: {
1.14 markus 310: cipher_encrypt(cc, dest, src, bytes);
1.1 deraadt 311: }
312:
1.16 markus 313: /*
314: * Decrypts the given number of bytes, copying from src to dest. bytes is
315: * known to be a multiple of 8.
316: */
1.1 deraadt 317:
1.2 provos 318: void
1.40 markus 319: packet_decrypt(CipherContext *context, void *dest, void *src, u_int bytes)
1.1 deraadt 320: {
1.16 markus 321: /*
322: * Cryptographic attack detector for ssh - Modifications for packet.c
323: * (C)1998 CORE-SDI, Buenos Aires Argentina Ariel Futoransky(futo@core-sdi.com)
324: */
1.37 markus 325: if (!compat20 &&
326: context->cipher->number != SSH_CIPHER_NONE &&
327: detect_attack(src, bytes, NULL) == DEATTACK_DETECTED)
1.14 markus 328: packet_disconnect("crc32 compensation attack: network attack detected");
329:
1.37 markus 330: cipher_decrypt(context, dest, src, bytes);
1.1 deraadt 331: }
332:
1.16 markus 333: /*
334: * Causes any further packets to be encrypted using the given key. The same
335: * key is used for both sending and reception. However, both directions are
336: * encrypted independently of each other.
337: */
1.1 deraadt 338:
1.2 provos 339: void
1.40 markus 340: packet_set_encryption_key(const u_char *key, u_int keylen,
1.37 markus 341: int number)
1.1 deraadt 342: {
1.37 markus 343: Cipher *cipher = cipher_by_number(number);
344: if (cipher == NULL)
345: fatal("packet_set_encryption_key: unknown cipher number %d", number);
1.25 markus 346: if (keylen < 20)
1.37 markus 347: fatal("packet_set_encryption_key: keylen too small: %d", keylen);
348: cipher_init(&receive_context, cipher, key, keylen, NULL, 0);
349: cipher_init(&send_context, cipher, key, keylen, NULL, 0);
1.1 deraadt 350: }
351:
352: /* Starts constructing a packet to send. */
353:
1.2 provos 354: void
1.25 markus 355: packet_start1(int type)
1.1 deraadt 356: {
1.14 markus 357: char buf[9];
1.1 deraadt 358:
1.14 markus 359: buffer_clear(&outgoing_packet);
360: memset(buf, 0, 8);
361: buf[8] = type;
362: buffer_append(&outgoing_packet, buf, 9);
1.1 deraadt 363: }
364:
1.25 markus 365: void
366: packet_start2(int type)
367: {
368: char buf[4+1+1];
369:
370: buffer_clear(&outgoing_packet);
371: memset(buf, 0, sizeof buf);
372: /* buf[0..3] = payload_len; */
373: /* buf[4] = pad_len; */
374: buf[5] = type & 0xff;
375: buffer_append(&outgoing_packet, buf, sizeof buf);
376: }
377:
378: void
379: packet_start(int type)
380: {
1.55 deraadt 381: DBG(debug("packet_start[%d]", type));
1.25 markus 382: if (use_ssh2_packet_format)
383: packet_start2(type);
384: else
385: packet_start1(type);
386: }
387:
1.1 deraadt 388: /* Appends a character to the packet data. */
389:
1.2 provos 390: void
391: packet_put_char(int value)
1.1 deraadt 392: {
1.14 markus 393: char ch = value;
394: buffer_append(&outgoing_packet, &ch, 1);
1.1 deraadt 395: }
396:
397: /* Appends an integer to the packet data. */
398:
1.2 provos 399: void
1.40 markus 400: packet_put_int(u_int value)
1.1 deraadt 401: {
1.14 markus 402: buffer_put_int(&outgoing_packet, value);
1.1 deraadt 403: }
404:
405: /* Appends a string to packet data. */
406:
1.2 provos 407: void
1.40 markus 408: packet_put_string(const char *buf, u_int len)
1.1 deraadt 409: {
1.14 markus 410: buffer_put_string(&outgoing_packet, buf, len);
1.1 deraadt 411: }
1.24 markus 412: void
413: packet_put_cstring(const char *str)
414: {
415: buffer_put_string(&outgoing_packet, str, strlen(str));
416: }
417:
418: void
1.40 markus 419: packet_put_raw(const char *buf, u_int len)
1.24 markus 420: {
421: buffer_append(&outgoing_packet, buf, len);
422: }
423:
1.1 deraadt 424:
425: /* Appends an arbitrary precision integer to packet data. */
426:
1.2 provos 427: void
1.14 markus 428: packet_put_bignum(BIGNUM * value)
1.1 deraadt 429: {
1.14 markus 430: buffer_put_bignum(&outgoing_packet, value);
1.1 deraadt 431: }
1.24 markus 432: void
433: packet_put_bignum2(BIGNUM * value)
434: {
435: buffer_put_bignum2(&outgoing_packet, value);
436: }
1.1 deraadt 437:
1.16 markus 438: /*
439: * Finalizes and sends the packet. If the encryption key has been set,
440: * encrypts the packet before sending.
441: */
1.14 markus 442:
1.2 provos 443: void
1.49 itojun 444: packet_send1(void)
1.1 deraadt 445: {
1.14 markus 446: char buf[8], *cp;
447: int i, padding, len;
1.40 markus 448: u_int checksum;
1.14 markus 449: u_int32_t rand = 0;
450:
1.16 markus 451: /*
452: * If using packet compression, compress the payload of the outgoing
453: * packet.
454: */
1.14 markus 455: if (packet_compression) {
456: buffer_clear(&compression_buffer);
457: /* Skip padding. */
458: buffer_consume(&outgoing_packet, 8);
459: /* padding */
460: buffer_append(&compression_buffer, "\0\0\0\0\0\0\0\0", 8);
461: buffer_compress(&outgoing_packet, &compression_buffer);
462: buffer_clear(&outgoing_packet);
463: buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer),
464: buffer_len(&compression_buffer));
465: }
466: /* Compute packet length without padding (add checksum, remove padding). */
467: len = buffer_len(&outgoing_packet) + 4 - 8;
468:
1.32 markus 469: /* Insert padding. Initialized to zero in packet_start1() */
1.14 markus 470: padding = 8 - len % 8;
471: if (cipher_type != SSH_CIPHER_NONE) {
472: cp = buffer_ptr(&outgoing_packet);
473: for (i = 0; i < padding; i++) {
474: if (i % 4 == 0)
475: rand = arc4random();
476: cp[7 - i] = rand & 0xff;
477: rand >>= 8;
478: }
479: }
480: buffer_consume(&outgoing_packet, 8 - padding);
481:
482: /* Add check bytes. */
1.40 markus 483: checksum = ssh_crc32((u_char *) buffer_ptr(&outgoing_packet),
1.34 deraadt 484: buffer_len(&outgoing_packet));
1.14 markus 485: PUT_32BIT(buf, checksum);
486: buffer_append(&outgoing_packet, buf, 4);
1.1 deraadt 487:
488: #ifdef PACKET_DEBUG
1.14 markus 489: fprintf(stderr, "packet_send plain: ");
490: buffer_dump(&outgoing_packet);
1.1 deraadt 491: #endif
492:
1.14 markus 493: /* Append to output. */
494: PUT_32BIT(buf, len);
495: buffer_append(&output, buf, 4);
496: buffer_append_space(&output, &cp, buffer_len(&outgoing_packet));
497: packet_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet),
498: buffer_len(&outgoing_packet));
499:
1.1 deraadt 500: #ifdef PACKET_DEBUG
1.14 markus 501: fprintf(stderr, "encrypted: ");
502: buffer_dump(&output);
1.1 deraadt 503: #endif
504:
1.14 markus 505: buffer_clear(&outgoing_packet);
1.1 deraadt 506:
1.16 markus 507: /*
508: * Note that the packet is now only buffered in output. It won\'t be
509: * actually sent until packet_write_wait or packet_write_poll is
510: * called.
511: */
1.1 deraadt 512: }
513:
1.57 markus 514: void
515: set_newkeys(int mode)
516: {
517: Enc *enc;
518: Mac *mac;
519: Comp *comp;
520: CipherContext *cc;
521:
522: debug("newkeys: mode %d", mode);
523:
524: cc = (mode == MODE_OUT) ? &send_context : &receive_context;
525: if (newkeys[mode] != NULL) {
526: debug("newkeys: rekeying");
527: memset(cc, 0, sizeof(*cc));
1.58 ! markus 528: /* todo: free old keys, reset compression/cipher-ctxt; */
! 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);
542: clear_enc_keys(enc, enc->cipher->key_len);
543: if (comp->type != 0 && comp->enabled == 0) {
544: comp->enabled = 1;
545: if (! packet_compression)
546: packet_start_compression(6);
547: }
548: }
549:
1.16 markus 550: /*
1.25 markus 551: * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue)
552: */
553: void
1.49 itojun 554: packet_send2(void)
1.25 markus 555: {
1.50 markus 556: static u_int32_t seqnr = 0;
1.40 markus 557: u_char *macbuf = NULL;
1.25 markus 558: char *cp;
1.40 markus 559: u_int packet_length = 0;
560: u_int i, padlen, len;
1.25 markus 561: u_int32_t rand = 0;
562: int type;
563: Enc *enc = NULL;
564: Mac *mac = NULL;
565: Comp *comp = NULL;
566: int block_size;
567:
1.57 markus 568: if (newkeys[MODE_OUT] != NULL) {
569: enc = &newkeys[MODE_OUT]->enc;
570: mac = &newkeys[MODE_OUT]->mac;
571: comp = &newkeys[MODE_OUT]->comp;
1.25 markus 572: }
1.37 markus 573: block_size = enc ? enc->cipher->block_size : 8;
1.25 markus 574:
575: cp = buffer_ptr(&outgoing_packet);
576: type = cp[5] & 0xff;
577:
578: #ifdef PACKET_DEBUG
579: fprintf(stderr, "plain: ");
580: buffer_dump(&outgoing_packet);
581: #endif
582:
583: if (comp && comp->enabled) {
584: len = buffer_len(&outgoing_packet);
585: /* skip header, compress only payload */
586: buffer_consume(&outgoing_packet, 5);
587: buffer_clear(&compression_buffer);
588: buffer_compress(&outgoing_packet, &compression_buffer);
589: buffer_clear(&outgoing_packet);
590: buffer_append(&outgoing_packet, "\0\0\0\0\0", 5);
591: buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer),
592: buffer_len(&compression_buffer));
593: DBG(debug("compression: raw %d compressed %d", len,
594: buffer_len(&outgoing_packet)));
595: }
596:
597: /* sizeof (packet_len + pad_len + payload) */
598: len = buffer_len(&outgoing_packet);
599:
600: /*
601: * calc size of padding, alloc space, get random data,
602: * minimum padding is 4 bytes
603: */
604: padlen = block_size - (len % block_size);
605: if (padlen < 4)
606: padlen += block_size;
607: buffer_append_space(&outgoing_packet, &cp, padlen);
1.38 markus 608: if (enc && enc->cipher->number != SSH_CIPHER_NONE) {
1.32 markus 609: /* random padding */
1.25 markus 610: for (i = 0; i < padlen; i++) {
611: if (i % 4 == 0)
612: rand = arc4random();
613: cp[i] = rand & 0xff;
1.52 markus 614: rand >>= 8;
1.25 markus 615: }
1.32 markus 616: } else {
617: /* clear padding */
618: memset(cp, 0, padlen);
1.25 markus 619: }
620: /* packet_length includes payload, padding and padding length field */
621: packet_length = buffer_len(&outgoing_packet) - 4;
622: cp = buffer_ptr(&outgoing_packet);
623: PUT_32BIT(cp, packet_length);
624: cp[4] = padlen & 0xff;
625: DBG(debug("send: len %d (includes padlen %d)", packet_length+4, padlen));
626:
627: /* compute MAC over seqnr and packet(length fields, payload, padding) */
628: if (mac && mac->enabled) {
1.50 markus 629: macbuf = mac_compute(mac, seqnr,
1.40 markus 630: (u_char *) buffer_ptr(&outgoing_packet),
1.50 markus 631: buffer_len(&outgoing_packet));
1.36 markus 632: DBG(debug("done calc MAC out #%d", seqnr));
1.25 markus 633: }
634: /* encrypt packet and append to output buffer. */
635: buffer_append_space(&output, &cp, buffer_len(&outgoing_packet));
636: packet_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet),
637: buffer_len(&outgoing_packet));
638: /* append unencrypted MAC */
639: if (mac && mac->enabled)
640: buffer_append(&output, (char *)macbuf, mac->mac_len);
641: #ifdef PACKET_DEBUG
642: fprintf(stderr, "encrypted: ");
643: buffer_dump(&output);
644: #endif
1.29 markus 645: /* increment sequence number for outgoing packets */
646: if (++seqnr == 0)
647: log("outgoing seqnr wraps around");
1.25 markus 648: buffer_clear(&outgoing_packet);
649:
1.57 markus 650: if (type == SSH2_MSG_NEWKEYS)
651: set_newkeys(MODE_OUT);
1.25 markus 652: }
653:
654: void
655: packet_send()
656: {
657: if (use_ssh2_packet_format)
658: packet_send2();
659: else
660: packet_send1();
661: DBG(debug("packet_send done"));
662: }
663:
664: /*
1.16 markus 665: * Waits until a packet has been received, and returns its type. Note that
666: * no other data is processed until this returns, so this function should not
667: * be used during the interactive session.
668: */
1.1 deraadt 669:
1.2 provos 670: int
671: packet_read(int *payload_len_ptr)
1.1 deraadt 672: {
1.14 markus 673: int type, len;
1.56 millert 674: fd_set *setp;
1.14 markus 675: char buf[8192];
1.25 markus 676: DBG(debug("packet_read()"));
1.14 markus 677:
1.56 millert 678: setp = (fd_set *)xmalloc(howmany(connection_in+1, NFDBITS) *
679: sizeof(fd_mask));
680:
1.14 markus 681: /* Since we are blocking, ensure that all written packets have been sent. */
682: packet_write_wait();
683:
684: /* Stay in the loop until we have received a complete packet. */
685: for (;;) {
686: /* Try to read a packet from the buffer. */
687: type = packet_read_poll(payload_len_ptr);
1.32 markus 688: if (!use_ssh2_packet_format && (
689: type == SSH_SMSG_SUCCESS
1.14 markus 690: || type == SSH_SMSG_FAILURE
691: || type == SSH_CMSG_EOF
1.32 markus 692: || type == SSH_CMSG_EXIT_CONFIRMATION))
1.14 markus 693: packet_integrity_check(*payload_len_ptr, 0, type);
694: /* If we got a packet, return it. */
1.56 millert 695: if (type != SSH_MSG_NONE) {
696: xfree(setp);
1.14 markus 697: return type;
1.56 millert 698: }
1.16 markus 699: /*
700: * Otherwise, wait for some data to arrive, add it to the
701: * buffer, and try again.
702: */
1.56 millert 703: memset(setp, 0, howmany(connection_in + 1, NFDBITS) *
704: sizeof(fd_mask));
705: FD_SET(connection_in, setp);
1.16 markus 706:
1.14 markus 707: /* Wait for some data to arrive. */
1.56 millert 708: while (select(connection_in + 1, setp, NULL, NULL, NULL) == -1 &&
1.51 deraadt 709: (errno == EAGAIN || errno == EINTR))
710: ;
1.16 markus 711:
1.14 markus 712: /* Read data from the socket. */
713: len = read(connection_in, buf, sizeof(buf));
1.18 markus 714: if (len == 0) {
715: log("Connection closed by %.200s", get_remote_ipaddr());
716: fatal_cleanup();
717: }
1.14 markus 718: if (len < 0)
719: fatal("Read from socket failed: %.100s", strerror(errno));
720: /* Append it to the buffer. */
721: packet_process_incoming(buf, len);
722: }
723: /* NOTREACHED */
1.1 deraadt 724: }
725:
1.16 markus 726: /*
727: * Waits until a packet has been received, verifies that its type matches
728: * that given, and gives a fatal error and exits if there is a mismatch.
729: */
1.1 deraadt 730:
1.2 provos 731: void
732: packet_read_expect(int *payload_len_ptr, int expected_type)
1.1 deraadt 733: {
1.14 markus 734: int type;
1.1 deraadt 735:
1.14 markus 736: type = packet_read(payload_len_ptr);
737: if (type != expected_type)
738: packet_disconnect("Protocol error: expected packet type %d, got %d",
1.25 markus 739: expected_type, type);
1.1 deraadt 740: }
741:
742: /* Checks if a full packet is available in the data received so far via
1.14 markus 743: * packet_process_incoming. If so, reads the packet; otherwise returns
744: * SSH_MSG_NONE. This does not wait for data from the connection.
745: *
746: * SSH_MSG_DISCONNECT is handled specially here. Also,
747: * SSH_MSG_IGNORE messages are skipped by this function and are never returned
748: * to higher levels.
749: *
750: * The returned payload_len does include space consumed by:
751: * Packet length
752: * Padding
753: * Packet type
754: * Check bytes
755: */
1.1 deraadt 756:
1.2 provos 757: int
1.25 markus 758: packet_read_poll1(int *payload_len_ptr)
1.1 deraadt 759: {
1.40 markus 760: u_int len, padded_len;
761: u_char *ucp;
1.25 markus 762: char buf[8], *cp;
1.40 markus 763: u_int checksum, stored_checksum;
1.14 markus 764:
765: /* Check if input size is less than minimum packet size. */
766: if (buffer_len(&input) < 4 + 8)
767: return SSH_MSG_NONE;
768: /* Get length of incoming packet. */
1.40 markus 769: ucp = (u_char *) buffer_ptr(&input);
1.14 markus 770: len = GET_32BIT(ucp);
771: if (len < 1 + 2 + 2 || len > 256 * 1024)
772: packet_disconnect("Bad packet length %d.", len);
773: padded_len = (len + 8) & ~7;
774:
775: /* Check if the packet has been entirely received. */
776: if (buffer_len(&input) < 4 + padded_len)
777: return SSH_MSG_NONE;
778:
779: /* The entire packet is in buffer. */
780:
781: /* Consume packet length. */
782: buffer_consume(&input, 4);
783:
784: /* Copy data to incoming_packet. */
785: buffer_clear(&incoming_packet);
786: buffer_append_space(&incoming_packet, &cp, padded_len);
787: packet_decrypt(&receive_context, cp, buffer_ptr(&input), padded_len);
788: buffer_consume(&input, padded_len);
1.1 deraadt 789:
790: #ifdef PACKET_DEBUG
1.14 markus 791: fprintf(stderr, "read_poll plain: ");
792: buffer_dump(&incoming_packet);
1.1 deraadt 793: #endif
794:
1.14 markus 795: /* Compute packet checksum. */
1.40 markus 796: checksum = ssh_crc32((u_char *) buffer_ptr(&incoming_packet),
1.25 markus 797: buffer_len(&incoming_packet) - 4);
1.14 markus 798:
799: /* Skip padding. */
800: buffer_consume(&incoming_packet, 8 - len % 8);
801:
802: /* Test check bytes. */
803:
804: if (len != buffer_len(&incoming_packet))
805: packet_disconnect("packet_read_poll: len %d != buffer_len %d.",
1.25 markus 806: len, buffer_len(&incoming_packet));
1.14 markus 807:
1.40 markus 808: ucp = (u_char *) buffer_ptr(&incoming_packet) + len - 4;
1.14 markus 809: stored_checksum = GET_32BIT(ucp);
810: if (checksum != stored_checksum)
811: packet_disconnect("Corrupted check bytes on input.");
812: buffer_consume_end(&incoming_packet, 4);
813:
814: /* If using packet compression, decompress the packet. */
815: if (packet_compression) {
816: buffer_clear(&compression_buffer);
817: buffer_uncompress(&incoming_packet, &compression_buffer);
818: buffer_clear(&incoming_packet);
819: buffer_append(&incoming_packet, buffer_ptr(&compression_buffer),
1.25 markus 820: buffer_len(&compression_buffer));
1.14 markus 821: }
822: /* Get packet type. */
823: buffer_get(&incoming_packet, &buf[0], 1);
824:
825: /* Return length of payload (without type field). */
826: *payload_len_ptr = buffer_len(&incoming_packet);
827:
828: /* Return type. */
1.40 markus 829: return (u_char) buf[0];
1.1 deraadt 830: }
1.14 markus 831:
1.25 markus 832: int
833: packet_read_poll2(int *payload_len_ptr)
834: {
1.50 markus 835: static u_int32_t seqnr = 0;
836: static u_int packet_length = 0;
1.40 markus 837: u_int padlen, need;
838: u_char buf[8], *macbuf;
839: u_char *ucp;
1.25 markus 840: char *cp;
841: int type;
842: int maclen, block_size;
843: Enc *enc = NULL;
844: Mac *mac = NULL;
845: Comp *comp = NULL;
846:
1.57 markus 847: if (newkeys[MODE_IN] != NULL) {
848: enc = &newkeys[MODE_IN]->enc;
849: mac = &newkeys[MODE_IN]->mac;
850: comp = &newkeys[MODE_IN]->comp;
1.25 markus 851: }
852: maclen = mac && mac->enabled ? mac->mac_len : 0;
1.37 markus 853: block_size = enc ? enc->cipher->block_size : 8;
1.25 markus 854:
855: if (packet_length == 0) {
856: /*
857: * check if input size is less than the cipher block size,
858: * decrypt first block and extract length of incoming packet
859: */
860: if (buffer_len(&input) < block_size)
861: return SSH_MSG_NONE;
862: buffer_clear(&incoming_packet);
863: buffer_append_space(&incoming_packet, &cp, block_size);
864: packet_decrypt(&receive_context, cp, buffer_ptr(&input),
865: block_size);
1.40 markus 866: ucp = (u_char *) buffer_ptr(&incoming_packet);
1.25 markus 867: packet_length = GET_32BIT(ucp);
868: if (packet_length < 1 + 4 || packet_length > 256 * 1024) {
869: buffer_dump(&incoming_packet);
870: packet_disconnect("Bad packet length %d.", packet_length);
871: }
872: DBG(debug("input: packet len %d", packet_length+4));
873: buffer_consume(&input, block_size);
874: }
875: /* we have a partial packet of block_size bytes */
876: need = 4 + packet_length - block_size;
877: DBG(debug("partial packet %d, need %d, maclen %d", block_size,
878: need, maclen));
879: if (need % block_size != 0)
880: fatal("padding error: need %d block %d mod %d",
881: need, block_size, need % block_size);
882: /*
883: * check if the entire packet has been received and
884: * decrypt into incoming_packet
885: */
886: if (buffer_len(&input) < need + maclen)
887: return SSH_MSG_NONE;
888: #ifdef PACKET_DEBUG
889: fprintf(stderr, "read_poll enc/full: ");
890: buffer_dump(&input);
891: #endif
892: buffer_append_space(&incoming_packet, &cp, need);
893: packet_decrypt(&receive_context, cp, buffer_ptr(&input), need);
894: buffer_consume(&input, need);
895: /*
896: * compute MAC over seqnr and packet,
897: * increment sequence number for incoming packet
898: */
1.29 markus 899: if (mac && mac->enabled) {
1.50 markus 900: macbuf = mac_compute(mac, seqnr,
1.40 markus 901: (u_char *) buffer_ptr(&incoming_packet),
1.50 markus 902: buffer_len(&incoming_packet));
1.25 markus 903: if (memcmp(macbuf, buffer_ptr(&input), mac->mac_len) != 0)
1.36 markus 904: packet_disconnect("Corrupted MAC on input.");
905: DBG(debug("MAC #%d ok", seqnr));
1.25 markus 906: buffer_consume(&input, mac->mac_len);
907: }
1.29 markus 908: if (++seqnr == 0)
909: log("incoming seqnr wraps around");
1.25 markus 910:
911: /* get padlen */
912: cp = buffer_ptr(&incoming_packet) + 4;
913: padlen = *cp & 0xff;
914: DBG(debug("input: padlen %d", padlen));
915: if (padlen < 4)
916: packet_disconnect("Corrupted padlen %d on input.", padlen);
917:
918: /* skip packet size + padlen, discard padding */
919: buffer_consume(&incoming_packet, 4 + 1);
920: buffer_consume_end(&incoming_packet, padlen);
921:
922: DBG(debug("input: len before de-compress %d", buffer_len(&incoming_packet)));
923: if (comp && comp->enabled) {
924: buffer_clear(&compression_buffer);
925: buffer_uncompress(&incoming_packet, &compression_buffer);
926: buffer_clear(&incoming_packet);
927: buffer_append(&incoming_packet, buffer_ptr(&compression_buffer),
928: buffer_len(&compression_buffer));
929: DBG(debug("input: len after de-compress %d", buffer_len(&incoming_packet)));
930: }
931: /*
932: * get packet type, implies consume.
933: * return length of payload (without type field)
934: */
935: buffer_get(&incoming_packet, (char *)&buf[0], 1);
936: *payload_len_ptr = buffer_len(&incoming_packet);
937:
938: /* reset for next packet */
939: packet_length = 0;
940:
941: /* extract packet type */
1.40 markus 942: type = (u_char)buf[0];
1.25 markus 943:
1.57 markus 944: if (type == SSH2_MSG_NEWKEYS)
945: set_newkeys(MODE_IN);
1.25 markus 946:
947: #ifdef PACKET_DEBUG
1.55 deraadt 948: fprintf(stderr, "read/plain[%d]:\r\n", type);
1.25 markus 949: buffer_dump(&incoming_packet);
950: #endif
1.40 markus 951: return (u_char)type;
1.25 markus 952: }
953:
954: int
955: packet_read_poll(int *payload_len_ptr)
956: {
957: char *msg;
958: for (;;) {
959: int type = use_ssh2_packet_format ?
960: packet_read_poll2(payload_len_ptr):
961: packet_read_poll1(payload_len_ptr);
962:
963: if(compat20) {
964: int reason;
965: if (type != 0)
966: DBG(debug("received packet type %d", type));
967: switch(type) {
968: case SSH2_MSG_IGNORE:
969: break;
970: case SSH2_MSG_DEBUG:
971: packet_get_char();
972: msg = packet_get_string(NULL);
973: debug("Remote: %.900s", msg);
974: xfree(msg);
975: msg = packet_get_string(NULL);
976: xfree(msg);
977: break;
978: case SSH2_MSG_DISCONNECT:
979: reason = packet_get_int();
980: msg = packet_get_string(NULL);
1.41 markus 981: log("Received disconnect from %s: %d: %.400s", get_remote_ipaddr(),
982: reason, msg);
1.25 markus 983: xfree(msg);
984: fatal_cleanup();
985: break;
986: default:
987: return type;
988: break;
1.48 stevesk 989: }
1.25 markus 990: } else {
991: switch(type) {
992: case SSH_MSG_IGNORE:
993: break;
994: case SSH_MSG_DEBUG:
995: msg = packet_get_string(NULL);
996: debug("Remote: %.900s", msg);
997: xfree(msg);
998: break;
999: case SSH_MSG_DISCONNECT:
1000: msg = packet_get_string(NULL);
1.41 markus 1001: log("Received disconnect from %s: %.400s", get_remote_ipaddr(),
1002: msg);
1.25 markus 1003: fatal_cleanup();
1004: xfree(msg);
1005: break;
1006: default:
1007: if (type != 0)
1008: DBG(debug("received packet type %d", type));
1009: return type;
1010: break;
1.48 stevesk 1011: }
1.25 markus 1012: }
1013: }
1014: }
1015:
1.16 markus 1016: /*
1017: * Buffers the given amount of input characters. This is intended to be used
1018: * together with packet_read_poll.
1019: */
1.1 deraadt 1020:
1.2 provos 1021: void
1.40 markus 1022: packet_process_incoming(const char *buf, u_int len)
1.1 deraadt 1023: {
1.14 markus 1024: buffer_append(&input, buf, len);
1.1 deraadt 1025: }
1026:
1027: /* Returns a character from the packet. */
1028:
1.40 markus 1029: u_int
1.2 provos 1030: packet_get_char()
1.1 deraadt 1031: {
1.14 markus 1032: char ch;
1033: buffer_get(&incoming_packet, &ch, 1);
1.40 markus 1034: return (u_char) ch;
1.1 deraadt 1035: }
1036:
1037: /* Returns an integer from the packet data. */
1038:
1.40 markus 1039: u_int
1.2 provos 1040: packet_get_int()
1.1 deraadt 1041: {
1.14 markus 1042: return buffer_get_int(&incoming_packet);
1.1 deraadt 1043: }
1044:
1.16 markus 1045: /*
1046: * Returns an arbitrary precision integer from the packet data. The integer
1047: * must have been initialized before this call.
1048: */
1.1 deraadt 1049:
1.2 provos 1050: void
1.14 markus 1051: packet_get_bignum(BIGNUM * value, int *length_ptr)
1.1 deraadt 1052: {
1.14 markus 1053: *length_ptr = buffer_get_bignum(&incoming_packet, value);
1.24 markus 1054: }
1055:
1056: void
1057: packet_get_bignum2(BIGNUM * value, int *length_ptr)
1058: {
1059: *length_ptr = buffer_get_bignum2(&incoming_packet, value);
1060: }
1061:
1062: char *
1063: packet_get_raw(int *length_ptr)
1064: {
1065: int bytes = buffer_len(&incoming_packet);
1066: if (length_ptr != NULL)
1067: *length_ptr = bytes;
1068: return buffer_ptr(&incoming_packet);
1.28 markus 1069: }
1070:
1071: int
1072: packet_remaining(void)
1073: {
1074: return buffer_len(&incoming_packet);
1.1 deraadt 1075: }
1076:
1.16 markus 1077: /*
1078: * Returns a string from the packet data. The string is allocated using
1079: * xmalloc; it is the responsibility of the calling program to free it when
1080: * no longer needed. The length_ptr argument may be NULL, or point to an
1081: * integer into which the length of the string is stored.
1082: */
1.1 deraadt 1083:
1.16 markus 1084: char *
1.40 markus 1085: packet_get_string(u_int *length_ptr)
1.1 deraadt 1086: {
1.14 markus 1087: return buffer_get_string(&incoming_packet, length_ptr);
1.1 deraadt 1088: }
1089:
1.16 markus 1090: /*
1091: * Sends a diagnostic message from the server to the client. This message
1092: * can be sent at any time (but not while constructing another message). The
1093: * message is printed immediately, but only if the client is being executed
1094: * in verbose mode. These messages are primarily intended to ease debugging
1095: * authentication problems. The length of the formatted message must not
1096: * exceed 1024 bytes. This will automatically call packet_write_wait.
1097: */
1.1 deraadt 1098:
1.2 provos 1099: void
1.14 markus 1100: packet_send_debug(const char *fmt,...)
1.1 deraadt 1101: {
1.14 markus 1102: char buf[1024];
1103: va_list args;
1.39 markus 1104:
1105: if (compat20 && (datafellows & SSH_BUG_DEBUG))
1106: return;
1.14 markus 1107:
1108: va_start(args, fmt);
1109: vsnprintf(buf, sizeof(buf), fmt, args);
1110: va_end(args);
1111:
1.30 markus 1112: if (compat20) {
1113: packet_start(SSH2_MSG_DEBUG);
1114: packet_put_char(0); /* bool: always display */
1115: packet_put_cstring(buf);
1116: packet_put_cstring("");
1117: } else {
1118: packet_start(SSH_MSG_DEBUG);
1119: packet_put_cstring(buf);
1120: }
1.14 markus 1121: packet_send();
1122: packet_write_wait();
1.1 deraadt 1123: }
1124:
1.16 markus 1125: /*
1126: * Logs the error plus constructs and sends a disconnect packet, closes the
1127: * connection, and exits. This function never returns. The error message
1128: * should not contain a newline. The length of the formatted message must
1129: * not exceed 1024 bytes.
1130: */
1.1 deraadt 1131:
1.2 provos 1132: void
1.14 markus 1133: packet_disconnect(const char *fmt,...)
1.1 deraadt 1134: {
1.14 markus 1135: char buf[1024];
1136: va_list args;
1137: static int disconnecting = 0;
1138: if (disconnecting) /* Guard against recursive invocations. */
1139: fatal("packet_disconnect called recursively.");
1140: disconnecting = 1;
1141:
1.16 markus 1142: /*
1143: * Format the message. Note that the caller must make sure the
1144: * message is of limited size.
1145: */
1.14 markus 1146: va_start(args, fmt);
1147: vsnprintf(buf, sizeof(buf), fmt, args);
1148: va_end(args);
1149:
1150: /* Send the disconnect message to the other side, and wait for it to get sent. */
1.25 markus 1151: if (compat20) {
1152: packet_start(SSH2_MSG_DISCONNECT);
1153: packet_put_int(SSH2_DISCONNECT_PROTOCOL_ERROR);
1154: packet_put_cstring(buf);
1155: packet_put_cstring("");
1156: } else {
1157: packet_start(SSH_MSG_DISCONNECT);
1158: packet_put_string(buf, strlen(buf));
1159: }
1.14 markus 1160: packet_send();
1161: packet_write_wait();
1162:
1163: /* Stop listening for connections. */
1164: channel_stop_listening();
1165:
1166: /* Close the connection. */
1167: packet_close();
1.1 deraadt 1168:
1.14 markus 1169: /* Display the error locally and exit. */
1.17 markus 1170: log("Disconnecting: %.100s", buf);
1171: fatal_cleanup();
1.1 deraadt 1172: }
1173:
1.16 markus 1174: /* Checks if there is any buffered output, and tries to write some of the output. */
1.1 deraadt 1175:
1.2 provos 1176: void
1177: packet_write_poll()
1.1 deraadt 1178: {
1.14 markus 1179: int len = buffer_len(&output);
1180: if (len > 0) {
1181: len = write(connection_out, buffer_ptr(&output), len);
1182: if (len <= 0) {
1183: if (errno == EAGAIN)
1184: return;
1185: else
1186: fatal("Write failed: %.100s", strerror(errno));
1187: }
1188: buffer_consume(&output, len);
1189: }
1.1 deraadt 1190: }
1191:
1.16 markus 1192: /*
1193: * Calls packet_write_poll repeatedly until all pending output data has been
1194: * written.
1195: */
1.1 deraadt 1196:
1.2 provos 1197: void
1198: packet_write_wait()
1.1 deraadt 1199: {
1.56 millert 1200: fd_set *setp;
1201:
1202: setp = (fd_set *)xmalloc(howmany(connection_out + 1, NFDBITS) *
1203: sizeof(fd_mask));
1.14 markus 1204: packet_write_poll();
1205: while (packet_have_data_to_write()) {
1.56 millert 1206: memset(setp, 0, howmany(connection_out + 1, NFDBITS) *
1207: sizeof(fd_mask));
1208: FD_SET(connection_out, setp);
1209: while (select(connection_out + 1, NULL, setp, NULL, NULL) == -1 &&
1.51 deraadt 1210: (errno == EAGAIN || errno == EINTR))
1211: ;
1.14 markus 1212: packet_write_poll();
1213: }
1.56 millert 1214: xfree(setp);
1.1 deraadt 1215: }
1216:
1217: /* Returns true if there is buffered data to write to the connection. */
1218:
1.2 provos 1219: int
1220: packet_have_data_to_write()
1.1 deraadt 1221: {
1.14 markus 1222: return buffer_len(&output) != 0;
1.1 deraadt 1223: }
1224:
1225: /* Returns true if there is not too much data to write to the connection. */
1226:
1.2 provos 1227: int
1228: packet_not_very_much_data_to_write()
1.1 deraadt 1229: {
1.14 markus 1230: if (interactive_mode)
1231: return buffer_len(&output) < 16384;
1232: else
1233: return buffer_len(&output) < 128 * 1024;
1.1 deraadt 1234: }
1235:
1236: /* Informs that the current session is interactive. Sets IP flags for that. */
1237:
1.2 provos 1238: void
1.43 markus 1239: packet_set_interactive(int interactive)
1.1 deraadt 1240: {
1.43 markus 1241: static int called = 0;
1.44 markus 1242: int lowdelay = IPTOS_LOWDELAY;
1243: int throughput = IPTOS_THROUGHPUT;
1244: int on = 1;
1245:
1.43 markus 1246: if (called)
1247: return;
1248: called = 1;
1.1 deraadt 1249:
1.14 markus 1250: /* Record that we are in interactive mode. */
1251: interactive_mode = interactive;
1.1 deraadt 1252:
1.19 markus 1253: /* Only set socket options if using a socket. */
1254: if (!packet_connection_is_on_socket())
1.14 markus 1255: return;
1.19 markus 1256: /*
1.42 markus 1257: * IPTOS_LOWDELAY and IPTOS_THROUGHPUT are IPv4 only
1.19 markus 1258: */
1.14 markus 1259: if (interactive) {
1.16 markus 1260: /*
1261: * Set IP options for an interactive connection. Use
1262: * IPTOS_LOWDELAY and TCP_NODELAY.
1263: */
1.42 markus 1264: if (packet_connection_is_ipv4()) {
1265: if (setsockopt(connection_in, IPPROTO_IP, IP_TOS,
1266: (void *) &lowdelay, sizeof(lowdelay)) < 0)
1267: error("setsockopt IPTOS_LOWDELAY: %.100s",
1268: strerror(errno));
1269: }
1.14 markus 1270: if (setsockopt(connection_in, IPPROTO_TCP, TCP_NODELAY, (void *) &on,
1.19 markus 1271: sizeof(on)) < 0)
1.14 markus 1272: error("setsockopt TCP_NODELAY: %.100s", strerror(errno));
1.42 markus 1273: } else if (packet_connection_is_ipv4()) {
1.16 markus 1274: /*
1275: * Set IP options for a non-interactive connection. Use
1276: * IPTOS_THROUGHPUT.
1277: */
1.14 markus 1278: if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, (void *) &throughput,
1.19 markus 1279: sizeof(throughput)) < 0)
1.14 markus 1280: error("setsockopt IPTOS_THROUGHPUT: %.100s", strerror(errno));
1281: }
1.1 deraadt 1282: }
1283:
1284: /* Returns true if the current connection is interactive. */
1285:
1.2 provos 1286: int
1287: packet_is_interactive()
1.1 deraadt 1288: {
1.14 markus 1289: return interactive_mode;
1.12 markus 1290: }
1291:
1292: int
1293: packet_set_maxsize(int s)
1294: {
1.14 markus 1295: static int called = 0;
1296: if (called) {
1.25 markus 1297: log("packet_set_maxsize: called twice: old %d new %d",
1298: max_packet_size, s);
1.14 markus 1299: return -1;
1300: }
1301: if (s < 4 * 1024 || s > 1024 * 1024) {
1302: log("packet_set_maxsize: bad size %d", s);
1303: return -1;
1304: }
1305: log("packet_set_maxsize: setting to %d", s);
1306: max_packet_size = s;
1307: return s;
1.53 markus 1308: }
1309:
1310: /*
1311: * 9.2. Ignored Data Message
1312: *
1313: * byte SSH_MSG_IGNORE
1314: * string data
1315: *
1316: * All implementations MUST understand (and ignore) this message at any
1317: * time (after receiving the protocol version). No implementation is
1318: * required to send them. This message can be used as an additional
1319: * protection measure against advanced traffic analysis techniques.
1320: */
1321: /* size of current + ignore message should be n*sumlen bytes (w/o mac) */
1322: void
1323: packet_inject_ignore(int sumlen)
1324: {
1.54 markus 1325: int blocksize, padlen, have, need, nb, mini, nbytes;
1.53 markus 1326: Enc *enc = NULL;
1327:
1328: if (use_ssh2_packet_format == 0)
1329: return;
1330:
1331: have = buffer_len(&outgoing_packet);
1332: debug2("packet_inject_ignore: current %d", have);
1.57 markus 1333: if (newkeys[MODE_OUT] != NULL)
1334: enc = &newkeys[MODE_OUT]->enc;
1.53 markus 1335: blocksize = enc ? enc->cipher->block_size : 8;
1336: padlen = blocksize - (have % blocksize);
1337: if (padlen < 4)
1338: padlen += blocksize;
1339: have += padlen;
1340: have /= blocksize; /* # of blocks for current message */
1341:
1342: nb = roundup(sumlen, blocksize) / blocksize; /* blocks for both */
1343: mini = roundup(5+1+4+4, blocksize) / blocksize; /* minsize ignore msg */
1344: need = nb - (have % nb); /* blocks for ignore */
1345: if (need <= mini)
1346: need += nb;
1347: nbytes = (need - mini) * blocksize; /* size of ignore payload */
1348: debug2("packet_inject_ignore: block %d have %d nb %d mini %d need %d",
1349: blocksize, have, nb, mini, need);
1350:
1351: /* enqueue current message and append a ignore message */
1352: packet_send();
1.54 markus 1353: packet_send_ignore(nbytes);
1354: }
1355:
1356: void
1357: packet_send_ignore(int nbytes)
1358: {
1359: u_int32_t rand = 0;
1360: int i;
1361:
1362: packet_start(compat20 ? SSH2_MSG_IGNORE : SSH_MSG_IGNORE);
1.53 markus 1363: packet_put_int(nbytes);
1364: for(i = 0; i < nbytes; i++) {
1365: if (i % 4 == 0)
1366: rand = arc4random();
1367: packet_put_char(rand & 0xff);
1368: rand >>= 8;
1369: }
1.1 deraadt 1370: }
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