Annotation of src/usr.bin/ssh/packet.c, Revision 1.38.2.4
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"
1.38.2.4! jason 40: RCSID("$OpenBSD: packet.c,v 1.61 2001/04/05 10:42:51 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"
1.38.2.1 jason 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"
1.38.2.1 jason 59: #include "mac.h"
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. */
1.38.2.1 jason 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;
1.38.2.4! jason 107: static int compression_buffer_ready = 0;
1.1 deraadt 108:
109: /* Flag indicating whether packet compression/decompression is enabled. */
110: static int packet_compression = 0;
111:
1.12 markus 112: /* default maximum packet size */
113: int max_packet_size = 32768;
114:
1.1 deraadt 115: /* Flag indicating whether this module has been initialized. */
116: static int initialized = 0;
117:
118: /* Set to true if the connection is interactive. */
119: static int interactive_mode = 0;
120:
1.25 markus 121: /* True if SSH2 packet format is used */
122: int use_ssh2_packet_format = 0;
123:
124: /* Session key information for Encryption and MAC */
1.38.2.4! jason 125: Newkeys *newkeys[MODE_MAX];
1.25 markus 126:
127: void
128: packet_set_ssh2_format(void)
129: {
1.31 markus 130: DBG(debug("use_ssh2_packet_format"));
1.25 markus 131: use_ssh2_packet_format = 1;
1.38.2.4! jason 132: newkeys[MODE_IN] = newkeys[MODE_OUT] = NULL;
1.25 markus 133: }
134:
1.16 markus 135: /*
136: * Sets the descriptors used for communication. Disables encryption until
137: * packet_set_encryption_key is called.
138: */
1.2 provos 139: void
140: packet_set_connection(int fd_in, int fd_out)
1.1 deraadt 141: {
1.37 markus 142: Cipher *none = cipher_by_name("none");
143: if (none == NULL)
144: fatal("packet_set_connection: cannot load cipher 'none'");
1.14 markus 145: connection_in = fd_in;
146: connection_out = fd_out;
147: cipher_type = SSH_CIPHER_NONE;
1.38.2.1 jason 148: cipher_init(&send_context, none, (u_char *) "", 0, NULL, 0);
149: cipher_init(&receive_context, none, (u_char *) "", 0, NULL, 0);
1.14 markus 150: if (!initialized) {
151: initialized = 1;
152: buffer_init(&input);
153: buffer_init(&output);
154: buffer_init(&outgoing_packet);
155: buffer_init(&incoming_packet);
156: }
157: /* Kludge: arrange the close function to be called from fatal(). */
158: fatal_add_cleanup((void (*) (void *)) packet_close, NULL);
1.1 deraadt 159: }
160:
1.19 markus 161: /* Returns 1 if remote host is connected via socket, 0 if not. */
162:
163: int
164: packet_connection_is_on_socket()
165: {
166: struct sockaddr_storage from, to;
167: socklen_t fromlen, tolen;
168:
169: /* filedescriptors in and out are the same, so it's a socket */
170: if (connection_in == connection_out)
171: return 1;
172: fromlen = sizeof(from);
173: memset(&from, 0, sizeof(from));
1.20 markus 174: if (getpeername(connection_in, (struct sockaddr *)&from, &fromlen) < 0)
1.19 markus 175: return 0;
176: tolen = sizeof(to);
177: memset(&to, 0, sizeof(to));
1.20 markus 178: if (getpeername(connection_out, (struct sockaddr *)&to, &tolen) < 0)
1.19 markus 179: return 0;
180: if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0)
181: return 0;
182: if (from.ss_family != AF_INET && from.ss_family != AF_INET6)
183: return 0;
184: return 1;
185: }
186:
187: /* returns 1 if connection is via ipv4 */
188:
189: int
190: packet_connection_is_ipv4()
191: {
192: struct sockaddr_storage to;
1.21 deraadt 193: socklen_t tolen = sizeof(to);
1.19 markus 194:
195: memset(&to, 0, sizeof(to));
196: if (getsockname(connection_out, (struct sockaddr *)&to, &tolen) < 0)
197: return 0;
198: if (to.ss_family != AF_INET)
199: return 0;
200: return 1;
201: }
202:
1.1 deraadt 203: /* Sets the connection into non-blocking mode. */
204:
1.2 provos 205: void
206: packet_set_nonblocking()
1.1 deraadt 207: {
1.14 markus 208: /* Set the socket into non-blocking mode. */
209: if (fcntl(connection_in, F_SETFL, O_NONBLOCK) < 0)
210: error("fcntl O_NONBLOCK: %.100s", strerror(errno));
211:
212: if (connection_out != connection_in) {
213: if (fcntl(connection_out, F_SETFL, O_NONBLOCK) < 0)
214: error("fcntl O_NONBLOCK: %.100s", strerror(errno));
215: }
1.1 deraadt 216: }
217:
218: /* Returns the socket used for reading. */
219:
1.2 provos 220: int
221: packet_get_connection_in()
1.1 deraadt 222: {
1.14 markus 223: return connection_in;
1.1 deraadt 224: }
225:
226: /* Returns the descriptor used for writing. */
227:
1.2 provos 228: int
229: packet_get_connection_out()
1.1 deraadt 230: {
1.14 markus 231: return connection_out;
1.1 deraadt 232: }
233:
234: /* Closes the connection and clears and frees internal data structures. */
235:
1.2 provos 236: void
237: packet_close()
1.1 deraadt 238: {
1.14 markus 239: if (!initialized)
240: return;
241: initialized = 0;
242: if (connection_in == connection_out) {
243: shutdown(connection_out, SHUT_RDWR);
244: close(connection_out);
245: } else {
246: close(connection_in);
247: close(connection_out);
248: }
249: buffer_free(&input);
250: buffer_free(&output);
251: buffer_free(&outgoing_packet);
252: buffer_free(&incoming_packet);
1.38.2.4! jason 253: if (compression_buffer_ready) {
1.14 markus 254: buffer_free(&compression_buffer);
255: buffer_compress_uninit();
256: }
1.1 deraadt 257: }
258:
259: /* Sets remote side protocol flags. */
260:
1.2 provos 261: void
1.38.2.1 jason 262: packet_set_protocol_flags(u_int protocol_flags)
1.1 deraadt 263: {
1.14 markus 264: remote_protocol_flags = protocol_flags;
265: channel_set_options((protocol_flags & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) != 0);
1.1 deraadt 266: }
267:
268: /* Returns the remote protocol flags set earlier by the above function. */
269:
1.38.2.1 jason 270: u_int
1.2 provos 271: packet_get_protocol_flags()
1.1 deraadt 272: {
1.14 markus 273: return remote_protocol_flags;
1.1 deraadt 274: }
275:
1.16 markus 276: /*
277: * Starts packet compression from the next packet on in both directions.
278: * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip.
279: */
1.1 deraadt 280:
1.38.2.4! jason 281: void
! 282: packet_init_compression()
! 283: {
! 284: if (compression_buffer_ready == 1)
! 285: return;
! 286: compression_buffer_ready = 1;
! 287: buffer_init(&compression_buffer);
! 288: }
! 289:
1.2 provos 290: void
291: packet_start_compression(int level)
1.1 deraadt 292: {
1.38.2.4! jason 293: if (packet_compression && !use_ssh2_packet_format)
1.14 markus 294: fatal("Compression already enabled.");
295: packet_compression = 1;
1.38.2.4! jason 296: packet_init_compression();
! 297: buffer_compress_init_send(level);
! 298: buffer_compress_init_recv();
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,
1.38.2.1 jason 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
1.38.2.1 jason 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
1.38.2.1 jason 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: {
1.38.2.3 jason 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
1.38.2.1 jason 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
1.38.2.1 jason 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
1.38.2.1 jason 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
1.38.2.1 jason 444: packet_send1(void)
1.1 deraadt 445: {
1.14 markus 446: char buf[8], *cp;
447: int i, padding, len;
1.38.2.1 jason 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. */
1.38.2.1 jason 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:
1.38.2.4! jason 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: /* todo: free old keys, reset compression/cipher-ctxt; */
! 528: memset(cc, 0, sizeof(*cc));
! 529: enc = &newkeys[mode]->enc;
! 530: mac = &newkeys[mode]->mac;
! 531: comp = &newkeys[mode]->comp;
! 532: memset(mac->key, 0, mac->key_len);
! 533: xfree(enc->name);
! 534: xfree(enc->iv);
! 535: xfree(enc->key);
! 536: xfree(mac->name);
! 537: xfree(mac->key);
! 538: xfree(comp->name);
! 539: xfree(newkeys[mode]);
! 540: }
! 541: newkeys[mode] = kex_get_newkeys(mode);
! 542: if (newkeys[mode] == NULL)
! 543: fatal("newkeys: no keys for mode %d", mode);
! 544: enc = &newkeys[mode]->enc;
! 545: mac = &newkeys[mode]->mac;
! 546: comp = &newkeys[mode]->comp;
! 547: if (mac->md != NULL)
! 548: mac->enabled = 1;
! 549: DBG(debug("cipher_init_context: %d", mode));
! 550: cipher_init(cc, enc->cipher, enc->key, enc->cipher->key_len,
! 551: enc->iv, enc->cipher->block_size);
! 552: memset(enc->iv, 0, enc->cipher->block_size);
! 553: memset(enc->key, 0, enc->cipher->key_len);
! 554: if (comp->type != 0 && comp->enabled == 0) {
! 555: packet_init_compression();
! 556: if (mode == MODE_OUT)
! 557: buffer_compress_init_send(6);
! 558: else
! 559: buffer_compress_init_recv();
! 560: comp->enabled = 1;
! 561: }
! 562: }
! 563:
1.16 markus 564: /*
1.25 markus 565: * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue)
566: */
567: void
1.38.2.1 jason 568: packet_send2(void)
1.25 markus 569: {
1.38.2.1 jason 570: static u_int32_t seqnr = 0;
571: u_char *macbuf = NULL;
1.25 markus 572: char *cp;
1.38.2.1 jason 573: u_int packet_length = 0;
574: u_int i, padlen, len;
1.25 markus 575: u_int32_t rand = 0;
576: int type;
577: Enc *enc = NULL;
578: Mac *mac = NULL;
579: Comp *comp = NULL;
580: int block_size;
581:
1.38.2.4! jason 582: if (newkeys[MODE_OUT] != NULL) {
! 583: enc = &newkeys[MODE_OUT]->enc;
! 584: mac = &newkeys[MODE_OUT]->mac;
! 585: comp = &newkeys[MODE_OUT]->comp;
1.25 markus 586: }
1.37 markus 587: block_size = enc ? enc->cipher->block_size : 8;
1.25 markus 588:
589: cp = buffer_ptr(&outgoing_packet);
590: type = cp[5] & 0xff;
591:
592: #ifdef PACKET_DEBUG
593: fprintf(stderr, "plain: ");
594: buffer_dump(&outgoing_packet);
595: #endif
596:
597: if (comp && comp->enabled) {
598: len = buffer_len(&outgoing_packet);
599: /* skip header, compress only payload */
600: buffer_consume(&outgoing_packet, 5);
601: buffer_clear(&compression_buffer);
602: buffer_compress(&outgoing_packet, &compression_buffer);
603: buffer_clear(&outgoing_packet);
604: buffer_append(&outgoing_packet, "\0\0\0\0\0", 5);
605: buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer),
606: buffer_len(&compression_buffer));
607: DBG(debug("compression: raw %d compressed %d", len,
608: buffer_len(&outgoing_packet)));
609: }
610:
611: /* sizeof (packet_len + pad_len + payload) */
612: len = buffer_len(&outgoing_packet);
613:
614: /*
615: * calc size of padding, alloc space, get random data,
616: * minimum padding is 4 bytes
617: */
618: padlen = block_size - (len % block_size);
619: if (padlen < 4)
620: padlen += block_size;
621: buffer_append_space(&outgoing_packet, &cp, padlen);
1.38 markus 622: if (enc && enc->cipher->number != SSH_CIPHER_NONE) {
1.32 markus 623: /* random padding */
1.25 markus 624: for (i = 0; i < padlen; i++) {
625: if (i % 4 == 0)
626: rand = arc4random();
627: cp[i] = rand & 0xff;
1.38.2.3 jason 628: rand >>= 8;
1.25 markus 629: }
1.32 markus 630: } else {
631: /* clear padding */
632: memset(cp, 0, padlen);
1.25 markus 633: }
634: /* packet_length includes payload, padding and padding length field */
635: packet_length = buffer_len(&outgoing_packet) - 4;
636: cp = buffer_ptr(&outgoing_packet);
637: PUT_32BIT(cp, packet_length);
638: cp[4] = padlen & 0xff;
639: DBG(debug("send: len %d (includes padlen %d)", packet_length+4, padlen));
640:
641: /* compute MAC over seqnr and packet(length fields, payload, padding) */
642: if (mac && mac->enabled) {
1.38.2.1 jason 643: macbuf = mac_compute(mac, seqnr,
644: (u_char *) buffer_ptr(&outgoing_packet),
645: buffer_len(&outgoing_packet));
1.36 markus 646: DBG(debug("done calc MAC out #%d", seqnr));
1.25 markus 647: }
648: /* encrypt packet and append to output buffer. */
649: buffer_append_space(&output, &cp, buffer_len(&outgoing_packet));
650: packet_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet),
651: buffer_len(&outgoing_packet));
652: /* append unencrypted MAC */
653: if (mac && mac->enabled)
654: buffer_append(&output, (char *)macbuf, mac->mac_len);
655: #ifdef PACKET_DEBUG
656: fprintf(stderr, "encrypted: ");
657: buffer_dump(&output);
658: #endif
1.29 markus 659: /* increment sequence number for outgoing packets */
660: if (++seqnr == 0)
661: log("outgoing seqnr wraps around");
1.25 markus 662: buffer_clear(&outgoing_packet);
663:
1.38.2.4! jason 664: if (type == SSH2_MSG_NEWKEYS)
! 665: set_newkeys(MODE_OUT);
1.25 markus 666: }
667:
668: void
669: packet_send()
670: {
671: if (use_ssh2_packet_format)
672: packet_send2();
673: else
674: packet_send1();
675: DBG(debug("packet_send done"));
676: }
677:
678: /*
1.16 markus 679: * Waits until a packet has been received, and returns its type. Note that
680: * no other data is processed until this returns, so this function should not
681: * be used during the interactive session.
682: */
1.1 deraadt 683:
1.2 provos 684: int
685: packet_read(int *payload_len_ptr)
1.1 deraadt 686: {
1.14 markus 687: int type, len;
1.38.2.3 jason 688: fd_set *setp;
1.14 markus 689: char buf[8192];
1.25 markus 690: DBG(debug("packet_read()"));
1.14 markus 691:
1.38.2.3 jason 692: setp = (fd_set *)xmalloc(howmany(connection_in+1, NFDBITS) *
693: sizeof(fd_mask));
694:
1.14 markus 695: /* Since we are blocking, ensure that all written packets have been sent. */
696: packet_write_wait();
697:
698: /* Stay in the loop until we have received a complete packet. */
699: for (;;) {
700: /* Try to read a packet from the buffer. */
701: type = packet_read_poll(payload_len_ptr);
1.32 markus 702: if (!use_ssh2_packet_format && (
703: type == SSH_SMSG_SUCCESS
1.14 markus 704: || type == SSH_SMSG_FAILURE
705: || type == SSH_CMSG_EOF
1.32 markus 706: || type == SSH_CMSG_EXIT_CONFIRMATION))
1.14 markus 707: packet_integrity_check(*payload_len_ptr, 0, type);
708: /* If we got a packet, return it. */
1.38.2.3 jason 709: if (type != SSH_MSG_NONE) {
710: xfree(setp);
1.14 markus 711: return type;
1.38.2.3 jason 712: }
1.16 markus 713: /*
714: * Otherwise, wait for some data to arrive, add it to the
715: * buffer, and try again.
716: */
1.38.2.3 jason 717: memset(setp, 0, howmany(connection_in + 1, NFDBITS) *
718: sizeof(fd_mask));
719: FD_SET(connection_in, setp);
1.16 markus 720:
1.14 markus 721: /* Wait for some data to arrive. */
1.38.2.3 jason 722: while (select(connection_in + 1, setp, NULL, NULL, NULL) == -1 &&
1.38.2.1 jason 723: (errno == EAGAIN || errno == EINTR))
724: ;
1.16 markus 725:
1.14 markus 726: /* Read data from the socket. */
727: len = read(connection_in, buf, sizeof(buf));
1.18 markus 728: if (len == 0) {
729: log("Connection closed by %.200s", get_remote_ipaddr());
730: fatal_cleanup();
731: }
1.14 markus 732: if (len < 0)
733: fatal("Read from socket failed: %.100s", strerror(errno));
734: /* Append it to the buffer. */
735: packet_process_incoming(buf, len);
736: }
737: /* NOTREACHED */
1.1 deraadt 738: }
739:
1.16 markus 740: /*
741: * Waits until a packet has been received, verifies that its type matches
742: * that given, and gives a fatal error and exits if there is a mismatch.
743: */
1.1 deraadt 744:
1.2 provos 745: void
746: packet_read_expect(int *payload_len_ptr, int expected_type)
1.1 deraadt 747: {
1.14 markus 748: int type;
1.1 deraadt 749:
1.14 markus 750: type = packet_read(payload_len_ptr);
751: if (type != expected_type)
752: packet_disconnect("Protocol error: expected packet type %d, got %d",
1.25 markus 753: expected_type, type);
1.1 deraadt 754: }
755:
756: /* Checks if a full packet is available in the data received so far via
1.14 markus 757: * packet_process_incoming. If so, reads the packet; otherwise returns
758: * SSH_MSG_NONE. This does not wait for data from the connection.
759: *
760: * SSH_MSG_DISCONNECT is handled specially here. Also,
761: * SSH_MSG_IGNORE messages are skipped by this function and are never returned
762: * to higher levels.
763: *
764: * The returned payload_len does include space consumed by:
765: * Packet length
766: * Padding
767: * Packet type
768: * Check bytes
769: */
1.1 deraadt 770:
1.2 provos 771: int
1.25 markus 772: packet_read_poll1(int *payload_len_ptr)
1.1 deraadt 773: {
1.38.2.1 jason 774: u_int len, padded_len;
775: u_char *ucp;
1.25 markus 776: char buf[8], *cp;
1.38.2.1 jason 777: u_int checksum, stored_checksum;
1.14 markus 778:
779: /* Check if input size is less than minimum packet size. */
780: if (buffer_len(&input) < 4 + 8)
781: return SSH_MSG_NONE;
782: /* Get length of incoming packet. */
1.38.2.1 jason 783: ucp = (u_char *) buffer_ptr(&input);
1.14 markus 784: len = GET_32BIT(ucp);
785: if (len < 1 + 2 + 2 || len > 256 * 1024)
786: packet_disconnect("Bad packet length %d.", len);
787: padded_len = (len + 8) & ~7;
788:
789: /* Check if the packet has been entirely received. */
790: if (buffer_len(&input) < 4 + padded_len)
791: return SSH_MSG_NONE;
792:
793: /* The entire packet is in buffer. */
794:
795: /* Consume packet length. */
796: buffer_consume(&input, 4);
797:
798: /* Copy data to incoming_packet. */
799: buffer_clear(&incoming_packet);
800: buffer_append_space(&incoming_packet, &cp, padded_len);
801: packet_decrypt(&receive_context, cp, buffer_ptr(&input), padded_len);
802: buffer_consume(&input, padded_len);
1.1 deraadt 803:
804: #ifdef PACKET_DEBUG
1.14 markus 805: fprintf(stderr, "read_poll plain: ");
806: buffer_dump(&incoming_packet);
1.1 deraadt 807: #endif
808:
1.14 markus 809: /* Compute packet checksum. */
1.38.2.1 jason 810: checksum = ssh_crc32((u_char *) buffer_ptr(&incoming_packet),
1.25 markus 811: buffer_len(&incoming_packet) - 4);
1.14 markus 812:
813: /* Skip padding. */
814: buffer_consume(&incoming_packet, 8 - len % 8);
815:
816: /* Test check bytes. */
817:
818: if (len != buffer_len(&incoming_packet))
819: packet_disconnect("packet_read_poll: len %d != buffer_len %d.",
1.25 markus 820: len, buffer_len(&incoming_packet));
1.14 markus 821:
1.38.2.1 jason 822: ucp = (u_char *) buffer_ptr(&incoming_packet) + len - 4;
1.14 markus 823: stored_checksum = GET_32BIT(ucp);
824: if (checksum != stored_checksum)
825: packet_disconnect("Corrupted check bytes on input.");
826: buffer_consume_end(&incoming_packet, 4);
827:
828: /* If using packet compression, decompress the packet. */
829: if (packet_compression) {
830: buffer_clear(&compression_buffer);
831: buffer_uncompress(&incoming_packet, &compression_buffer);
832: buffer_clear(&incoming_packet);
833: buffer_append(&incoming_packet, buffer_ptr(&compression_buffer),
1.25 markus 834: buffer_len(&compression_buffer));
1.14 markus 835: }
836: /* Get packet type. */
837: buffer_get(&incoming_packet, &buf[0], 1);
838:
839: /* Return length of payload (without type field). */
840: *payload_len_ptr = buffer_len(&incoming_packet);
841:
842: /* Return type. */
1.38.2.1 jason 843: return (u_char) buf[0];
1.1 deraadt 844: }
1.14 markus 845:
1.25 markus 846: int
847: packet_read_poll2(int *payload_len_ptr)
848: {
1.38.2.1 jason 849: static u_int32_t seqnr = 0;
850: static u_int packet_length = 0;
851: u_int padlen, need;
852: u_char buf[8], *macbuf;
853: u_char *ucp;
1.25 markus 854: char *cp;
855: int type;
856: int maclen, block_size;
857: Enc *enc = NULL;
858: Mac *mac = NULL;
859: Comp *comp = NULL;
860:
1.38.2.4! jason 861: if (newkeys[MODE_IN] != NULL) {
! 862: enc = &newkeys[MODE_IN]->enc;
! 863: mac = &newkeys[MODE_IN]->mac;
! 864: comp = &newkeys[MODE_IN]->comp;
1.25 markus 865: }
866: maclen = mac && mac->enabled ? mac->mac_len : 0;
1.37 markus 867: block_size = enc ? enc->cipher->block_size : 8;
1.25 markus 868:
869: if (packet_length == 0) {
870: /*
871: * check if input size is less than the cipher block size,
872: * decrypt first block and extract length of incoming packet
873: */
874: if (buffer_len(&input) < block_size)
875: return SSH_MSG_NONE;
876: buffer_clear(&incoming_packet);
877: buffer_append_space(&incoming_packet, &cp, block_size);
878: packet_decrypt(&receive_context, cp, buffer_ptr(&input),
879: block_size);
1.38.2.1 jason 880: ucp = (u_char *) buffer_ptr(&incoming_packet);
1.25 markus 881: packet_length = GET_32BIT(ucp);
882: if (packet_length < 1 + 4 || packet_length > 256 * 1024) {
883: buffer_dump(&incoming_packet);
884: packet_disconnect("Bad packet length %d.", packet_length);
885: }
886: DBG(debug("input: packet len %d", packet_length+4));
887: buffer_consume(&input, block_size);
888: }
889: /* we have a partial packet of block_size bytes */
890: need = 4 + packet_length - block_size;
891: DBG(debug("partial packet %d, need %d, maclen %d", block_size,
892: need, maclen));
893: if (need % block_size != 0)
894: fatal("padding error: need %d block %d mod %d",
895: need, block_size, need % block_size);
896: /*
897: * check if the entire packet has been received and
898: * decrypt into incoming_packet
899: */
900: if (buffer_len(&input) < need + maclen)
901: return SSH_MSG_NONE;
902: #ifdef PACKET_DEBUG
903: fprintf(stderr, "read_poll enc/full: ");
904: buffer_dump(&input);
905: #endif
906: buffer_append_space(&incoming_packet, &cp, need);
907: packet_decrypt(&receive_context, cp, buffer_ptr(&input), need);
908: buffer_consume(&input, need);
909: /*
910: * compute MAC over seqnr and packet,
911: * increment sequence number for incoming packet
912: */
1.29 markus 913: if (mac && mac->enabled) {
1.38.2.1 jason 914: macbuf = mac_compute(mac, seqnr,
915: (u_char *) buffer_ptr(&incoming_packet),
916: buffer_len(&incoming_packet));
1.25 markus 917: if (memcmp(macbuf, buffer_ptr(&input), mac->mac_len) != 0)
1.36 markus 918: packet_disconnect("Corrupted MAC on input.");
919: DBG(debug("MAC #%d ok", seqnr));
1.25 markus 920: buffer_consume(&input, mac->mac_len);
921: }
1.29 markus 922: if (++seqnr == 0)
923: log("incoming seqnr wraps around");
1.25 markus 924:
925: /* get padlen */
926: cp = buffer_ptr(&incoming_packet) + 4;
927: padlen = *cp & 0xff;
928: DBG(debug("input: padlen %d", padlen));
929: if (padlen < 4)
930: packet_disconnect("Corrupted padlen %d on input.", padlen);
931:
932: /* skip packet size + padlen, discard padding */
933: buffer_consume(&incoming_packet, 4 + 1);
934: buffer_consume_end(&incoming_packet, padlen);
935:
936: DBG(debug("input: len before de-compress %d", buffer_len(&incoming_packet)));
937: if (comp && comp->enabled) {
938: buffer_clear(&compression_buffer);
939: buffer_uncompress(&incoming_packet, &compression_buffer);
940: buffer_clear(&incoming_packet);
941: buffer_append(&incoming_packet, buffer_ptr(&compression_buffer),
942: buffer_len(&compression_buffer));
943: DBG(debug("input: len after de-compress %d", buffer_len(&incoming_packet)));
944: }
945: /*
946: * get packet type, implies consume.
947: * return length of payload (without type field)
948: */
949: buffer_get(&incoming_packet, (char *)&buf[0], 1);
950: *payload_len_ptr = buffer_len(&incoming_packet);
951:
952: /* reset for next packet */
953: packet_length = 0;
954:
955: /* extract packet type */
1.38.2.1 jason 956: type = (u_char)buf[0];
1.25 markus 957:
1.38.2.4! jason 958: if (type == SSH2_MSG_NEWKEYS)
! 959: set_newkeys(MODE_IN);
1.25 markus 960:
961: #ifdef PACKET_DEBUG
1.38.2.3 jason 962: fprintf(stderr, "read/plain[%d]:\r\n", type);
1.25 markus 963: buffer_dump(&incoming_packet);
964: #endif
1.38.2.1 jason 965: return (u_char)type;
1.25 markus 966: }
967:
968: int
969: packet_read_poll(int *payload_len_ptr)
970: {
971: char *msg;
972: for (;;) {
973: int type = use_ssh2_packet_format ?
974: packet_read_poll2(payload_len_ptr):
975: packet_read_poll1(payload_len_ptr);
976:
977: if(compat20) {
978: int reason;
979: if (type != 0)
980: DBG(debug("received packet type %d", type));
981: switch(type) {
982: case SSH2_MSG_IGNORE:
983: break;
984: case SSH2_MSG_DEBUG:
985: packet_get_char();
986: msg = packet_get_string(NULL);
987: debug("Remote: %.900s", msg);
988: xfree(msg);
989: msg = packet_get_string(NULL);
990: xfree(msg);
991: break;
992: case SSH2_MSG_DISCONNECT:
993: reason = packet_get_int();
994: msg = packet_get_string(NULL);
1.38.2.1 jason 995: log("Received disconnect from %s: %d: %.400s", get_remote_ipaddr(),
996: reason, msg);
1.25 markus 997: xfree(msg);
998: fatal_cleanup();
999: break;
1000: default:
1001: return type;
1002: break;
1.38.2.1 jason 1003: }
1.25 markus 1004: } else {
1005: switch(type) {
1006: case SSH_MSG_IGNORE:
1007: break;
1008: case SSH_MSG_DEBUG:
1009: msg = packet_get_string(NULL);
1010: debug("Remote: %.900s", msg);
1011: xfree(msg);
1012: break;
1013: case SSH_MSG_DISCONNECT:
1014: msg = packet_get_string(NULL);
1.38.2.1 jason 1015: log("Received disconnect from %s: %.400s", get_remote_ipaddr(),
1016: msg);
1.25 markus 1017: fatal_cleanup();
1018: xfree(msg);
1019: break;
1020: default:
1021: if (type != 0)
1022: DBG(debug("received packet type %d", type));
1023: return type;
1024: break;
1.38.2.1 jason 1025: }
1.25 markus 1026: }
1027: }
1028: }
1029:
1.16 markus 1030: /*
1031: * Buffers the given amount of input characters. This is intended to be used
1032: * together with packet_read_poll.
1033: */
1.1 deraadt 1034:
1.2 provos 1035: void
1.38.2.1 jason 1036: packet_process_incoming(const char *buf, u_int len)
1.1 deraadt 1037: {
1.14 markus 1038: buffer_append(&input, buf, len);
1.1 deraadt 1039: }
1040:
1041: /* Returns a character from the packet. */
1042:
1.38.2.1 jason 1043: u_int
1.2 provos 1044: packet_get_char()
1.1 deraadt 1045: {
1.14 markus 1046: char ch;
1047: buffer_get(&incoming_packet, &ch, 1);
1.38.2.1 jason 1048: return (u_char) ch;
1.1 deraadt 1049: }
1050:
1051: /* Returns an integer from the packet data. */
1052:
1.38.2.1 jason 1053: u_int
1.2 provos 1054: packet_get_int()
1.1 deraadt 1055: {
1.14 markus 1056: return buffer_get_int(&incoming_packet);
1.1 deraadt 1057: }
1058:
1.16 markus 1059: /*
1060: * Returns an arbitrary precision integer from the packet data. The integer
1061: * must have been initialized before this call.
1062: */
1.1 deraadt 1063:
1.2 provos 1064: void
1.14 markus 1065: packet_get_bignum(BIGNUM * value, int *length_ptr)
1.1 deraadt 1066: {
1.14 markus 1067: *length_ptr = buffer_get_bignum(&incoming_packet, value);
1.24 markus 1068: }
1069:
1070: void
1071: packet_get_bignum2(BIGNUM * value, int *length_ptr)
1072: {
1073: *length_ptr = buffer_get_bignum2(&incoming_packet, value);
1074: }
1075:
1076: char *
1077: packet_get_raw(int *length_ptr)
1078: {
1079: int bytes = buffer_len(&incoming_packet);
1080: if (length_ptr != NULL)
1081: *length_ptr = bytes;
1082: return buffer_ptr(&incoming_packet);
1.28 markus 1083: }
1084:
1085: int
1086: packet_remaining(void)
1087: {
1088: return buffer_len(&incoming_packet);
1.1 deraadt 1089: }
1090:
1.16 markus 1091: /*
1092: * Returns a string from the packet data. The string is allocated using
1093: * xmalloc; it is the responsibility of the calling program to free it when
1094: * no longer needed. The length_ptr argument may be NULL, or point to an
1095: * integer into which the length of the string is stored.
1096: */
1.1 deraadt 1097:
1.16 markus 1098: char *
1.38.2.1 jason 1099: packet_get_string(u_int *length_ptr)
1.1 deraadt 1100: {
1.14 markus 1101: return buffer_get_string(&incoming_packet, length_ptr);
1.1 deraadt 1102: }
1103:
1.16 markus 1104: /*
1105: * Sends a diagnostic message from the server to the client. This message
1106: * can be sent at any time (but not while constructing another message). The
1107: * message is printed immediately, but only if the client is being executed
1108: * in verbose mode. These messages are primarily intended to ease debugging
1109: * authentication problems. The length of the formatted message must not
1110: * exceed 1024 bytes. This will automatically call packet_write_wait.
1111: */
1.1 deraadt 1112:
1.2 provos 1113: void
1.14 markus 1114: packet_send_debug(const char *fmt,...)
1.1 deraadt 1115: {
1.14 markus 1116: char buf[1024];
1117: va_list args;
1118:
1.38.2.1 jason 1119: if (compat20 && (datafellows & SSH_BUG_DEBUG))
1120: return;
1121:
1.14 markus 1122: va_start(args, fmt);
1123: vsnprintf(buf, sizeof(buf), fmt, args);
1124: va_end(args);
1125:
1.30 markus 1126: if (compat20) {
1127: packet_start(SSH2_MSG_DEBUG);
1128: packet_put_char(0); /* bool: always display */
1129: packet_put_cstring(buf);
1130: packet_put_cstring("");
1131: } else {
1132: packet_start(SSH_MSG_DEBUG);
1133: packet_put_cstring(buf);
1134: }
1.14 markus 1135: packet_send();
1136: packet_write_wait();
1.1 deraadt 1137: }
1138:
1.16 markus 1139: /*
1140: * Logs the error plus constructs and sends a disconnect packet, closes the
1141: * connection, and exits. This function never returns. The error message
1142: * should not contain a newline. The length of the formatted message must
1143: * not exceed 1024 bytes.
1144: */
1.1 deraadt 1145:
1.2 provos 1146: void
1.14 markus 1147: packet_disconnect(const char *fmt,...)
1.1 deraadt 1148: {
1.14 markus 1149: char buf[1024];
1150: va_list args;
1151: static int disconnecting = 0;
1152: if (disconnecting) /* Guard against recursive invocations. */
1153: fatal("packet_disconnect called recursively.");
1154: disconnecting = 1;
1155:
1.16 markus 1156: /*
1157: * Format the message. Note that the caller must make sure the
1158: * message is of limited size.
1159: */
1.14 markus 1160: va_start(args, fmt);
1161: vsnprintf(buf, sizeof(buf), fmt, args);
1162: va_end(args);
1163:
1164: /* Send the disconnect message to the other side, and wait for it to get sent. */
1.25 markus 1165: if (compat20) {
1166: packet_start(SSH2_MSG_DISCONNECT);
1167: packet_put_int(SSH2_DISCONNECT_PROTOCOL_ERROR);
1168: packet_put_cstring(buf);
1169: packet_put_cstring("");
1170: } else {
1171: packet_start(SSH_MSG_DISCONNECT);
1172: packet_put_string(buf, strlen(buf));
1173: }
1.14 markus 1174: packet_send();
1175: packet_write_wait();
1176:
1177: /* Stop listening for connections. */
1178: channel_stop_listening();
1179:
1180: /* Close the connection. */
1181: packet_close();
1.1 deraadt 1182:
1.14 markus 1183: /* Display the error locally and exit. */
1.17 markus 1184: log("Disconnecting: %.100s", buf);
1185: fatal_cleanup();
1.1 deraadt 1186: }
1187:
1.16 markus 1188: /* Checks if there is any buffered output, and tries to write some of the output. */
1.1 deraadt 1189:
1.2 provos 1190: void
1191: packet_write_poll()
1.1 deraadt 1192: {
1.14 markus 1193: int len = buffer_len(&output);
1194: if (len > 0) {
1195: len = write(connection_out, buffer_ptr(&output), len);
1196: if (len <= 0) {
1197: if (errno == EAGAIN)
1198: return;
1199: else
1200: fatal("Write failed: %.100s", strerror(errno));
1201: }
1202: buffer_consume(&output, len);
1203: }
1.1 deraadt 1204: }
1205:
1.16 markus 1206: /*
1207: * Calls packet_write_poll repeatedly until all pending output data has been
1208: * written.
1209: */
1.1 deraadt 1210:
1.2 provos 1211: void
1212: packet_write_wait()
1.1 deraadt 1213: {
1.38.2.3 jason 1214: fd_set *setp;
1215:
1216: setp = (fd_set *)xmalloc(howmany(connection_out + 1, NFDBITS) *
1217: sizeof(fd_mask));
1.14 markus 1218: packet_write_poll();
1219: while (packet_have_data_to_write()) {
1.38.2.3 jason 1220: memset(setp, 0, howmany(connection_out + 1, NFDBITS) *
1221: sizeof(fd_mask));
1222: FD_SET(connection_out, setp);
1223: while (select(connection_out + 1, NULL, setp, NULL, NULL) == -1 &&
1.38.2.1 jason 1224: (errno == EAGAIN || errno == EINTR))
1225: ;
1.14 markus 1226: packet_write_poll();
1227: }
1.38.2.3 jason 1228: xfree(setp);
1.1 deraadt 1229: }
1230:
1231: /* Returns true if there is buffered data to write to the connection. */
1232:
1.2 provos 1233: int
1234: packet_have_data_to_write()
1.1 deraadt 1235: {
1.14 markus 1236: return buffer_len(&output) != 0;
1.1 deraadt 1237: }
1238:
1239: /* Returns true if there is not too much data to write to the connection. */
1240:
1.2 provos 1241: int
1242: packet_not_very_much_data_to_write()
1.1 deraadt 1243: {
1.14 markus 1244: if (interactive_mode)
1245: return buffer_len(&output) < 16384;
1246: else
1247: return buffer_len(&output) < 128 * 1024;
1.1 deraadt 1248: }
1249:
1250: /* Informs that the current session is interactive. Sets IP flags for that. */
1251:
1.2 provos 1252: void
1.38.2.1 jason 1253: packet_set_interactive(int interactive)
1.1 deraadt 1254: {
1.38.2.1 jason 1255: static int called = 0;
1256: int lowdelay = IPTOS_LOWDELAY;
1257: int throughput = IPTOS_THROUGHPUT;
1.14 markus 1258: int on = 1;
1.1 deraadt 1259:
1.38.2.1 jason 1260: if (called)
1261: return;
1262: called = 1;
1263:
1.14 markus 1264: /* Record that we are in interactive mode. */
1265: interactive_mode = interactive;
1.1 deraadt 1266:
1.19 markus 1267: /* Only set socket options if using a socket. */
1268: if (!packet_connection_is_on_socket())
1.14 markus 1269: return;
1.19 markus 1270: /*
1.38.2.1 jason 1271: * IPTOS_LOWDELAY and IPTOS_THROUGHPUT are IPv4 only
1.19 markus 1272: */
1.14 markus 1273: if (interactive) {
1.16 markus 1274: /*
1275: * Set IP options for an interactive connection. Use
1276: * IPTOS_LOWDELAY and TCP_NODELAY.
1277: */
1.38.2.1 jason 1278: if (packet_connection_is_ipv4()) {
1279: if (setsockopt(connection_in, IPPROTO_IP, IP_TOS,
1280: (void *) &lowdelay, sizeof(lowdelay)) < 0)
1281: error("setsockopt IPTOS_LOWDELAY: %.100s",
1282: strerror(errno));
1283: }
1.14 markus 1284: if (setsockopt(connection_in, IPPROTO_TCP, TCP_NODELAY, (void *) &on,
1.19 markus 1285: sizeof(on)) < 0)
1.14 markus 1286: error("setsockopt TCP_NODELAY: %.100s", strerror(errno));
1.38.2.1 jason 1287: } else if (packet_connection_is_ipv4()) {
1.16 markus 1288: /*
1289: * Set IP options for a non-interactive connection. Use
1290: * IPTOS_THROUGHPUT.
1291: */
1.14 markus 1292: if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, (void *) &throughput,
1.19 markus 1293: sizeof(throughput)) < 0)
1.14 markus 1294: error("setsockopt IPTOS_THROUGHPUT: %.100s", strerror(errno));
1295: }
1.1 deraadt 1296: }
1297:
1298: /* Returns true if the current connection is interactive. */
1299:
1.2 provos 1300: int
1301: packet_is_interactive()
1.1 deraadt 1302: {
1.14 markus 1303: return interactive_mode;
1.12 markus 1304: }
1305:
1306: int
1307: packet_set_maxsize(int s)
1308: {
1.14 markus 1309: static int called = 0;
1310: if (called) {
1.25 markus 1311: log("packet_set_maxsize: called twice: old %d new %d",
1312: max_packet_size, s);
1.14 markus 1313: return -1;
1314: }
1315: if (s < 4 * 1024 || s > 1024 * 1024) {
1316: log("packet_set_maxsize: bad size %d", s);
1317: return -1;
1318: }
1319: log("packet_set_maxsize: setting to %d", s);
1320: max_packet_size = s;
1321: return s;
1.38.2.3 jason 1322: }
1323:
1324: /*
1325: * 9.2. Ignored Data Message
1.38.2.4! jason 1326: *
1.38.2.3 jason 1327: * byte SSH_MSG_IGNORE
1328: * string data
1.38.2.4! jason 1329: *
1.38.2.3 jason 1330: * All implementations MUST understand (and ignore) this message at any
1331: * time (after receiving the protocol version). No implementation is
1332: * required to send them. This message can be used as an additional
1333: * protection measure against advanced traffic analysis techniques.
1334: */
1335: /* size of current + ignore message should be n*sumlen bytes (w/o mac) */
1336: void
1337: packet_inject_ignore(int sumlen)
1338: {
1339: int blocksize, padlen, have, need, nb, mini, nbytes;
1340: Enc *enc = NULL;
1341:
1342: if (use_ssh2_packet_format == 0)
1343: return;
1344:
1345: have = buffer_len(&outgoing_packet);
1346: debug2("packet_inject_ignore: current %d", have);
1.38.2.4! jason 1347: if (newkeys[MODE_OUT] != NULL)
! 1348: enc = &newkeys[MODE_OUT]->enc;
1.38.2.3 jason 1349: blocksize = enc ? enc->cipher->block_size : 8;
1350: padlen = blocksize - (have % blocksize);
1351: if (padlen < 4)
1352: padlen += blocksize;
1353: have += padlen;
1354: have /= blocksize; /* # of blocks for current message */
1355:
1356: nb = roundup(sumlen, blocksize) / blocksize; /* blocks for both */
1357: mini = roundup(5+1+4+4, blocksize) / blocksize; /* minsize ignore msg */
1358: need = nb - (have % nb); /* blocks for ignore */
1359: if (need <= mini)
1360: need += nb;
1361: nbytes = (need - mini) * blocksize; /* size of ignore payload */
1362: debug2("packet_inject_ignore: block %d have %d nb %d mini %d need %d",
1363: blocksize, have, nb, mini, need);
1364:
1365: /* enqueue current message and append a ignore message */
1366: packet_send();
1367: packet_send_ignore(nbytes);
1368: }
1369:
1370: void
1371: packet_send_ignore(int nbytes)
1372: {
1373: u_int32_t rand = 0;
1374: int i;
1375:
1376: packet_start(compat20 ? SSH2_MSG_IGNORE : SSH_MSG_IGNORE);
1377: packet_put_int(nbytes);
1378: for(i = 0; i < nbytes; i++) {
1379: if (i % 4 == 0)
1380: rand = arc4random();
1381: packet_put_char(rand & 0xff);
1382: rand >>= 8;
1383: }
1.1 deraadt 1384: }
![[BACK]](/icons/back.gif){kind=icon}
Return to packet.c CVS log ![[TXT]](/icons/text.gif){kind=icon}
![[DIR]](/icons/dir.gif){kind=icon}
Up to [local] / src / usr.bin / ssh