Annotation of src/usr.bin/ssh/packet.c, Revision 1.54
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"
1.54 ! markus 40: RCSID("$OpenBSD: packet.c,v 1.53 2001/02/28 09:57:06 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 */
124: Kex *kex = NULL;
125:
126: void
127: packet_set_kex(Kex *k)
128: {
129: if( k->mac[MODE_IN ].key == NULL ||
130: k->enc[MODE_IN ].key == NULL ||
131: k->enc[MODE_IN ].iv == NULL ||
132: k->mac[MODE_OUT].key == NULL ||
133: k->enc[MODE_OUT].key == NULL ||
134: k->enc[MODE_OUT].iv == NULL)
135: fatal("bad KEX");
136: kex = k;
137: }
138: void
139: clear_enc_keys(Enc *enc, int len)
140: {
141: memset(enc->iv, 0, len);
142: memset(enc->key, 0, len);
143: xfree(enc->iv);
144: xfree(enc->key);
145: enc->iv = NULL;
146: enc->key = NULL;
147: }
148: void
149: packet_set_ssh2_format(void)
150: {
1.31 markus 151: DBG(debug("use_ssh2_packet_format"));
1.25 markus 152: use_ssh2_packet_format = 1;
153: }
154:
1.16 markus 155: /*
156: * Sets the descriptors used for communication. Disables encryption until
157: * packet_set_encryption_key is called.
158: */
1.2 provos 159: void
160: packet_set_connection(int fd_in, int fd_out)
1.1 deraadt 161: {
1.37 markus 162: Cipher *none = cipher_by_name("none");
163: if (none == NULL)
164: fatal("packet_set_connection: cannot load cipher 'none'");
1.14 markus 165: connection_in = fd_in;
166: connection_out = fd_out;
167: cipher_type = SSH_CIPHER_NONE;
1.40 markus 168: cipher_init(&send_context, none, (u_char *) "", 0, NULL, 0);
169: cipher_init(&receive_context, none, (u_char *) "", 0, NULL, 0);
1.14 markus 170: if (!initialized) {
171: initialized = 1;
172: buffer_init(&input);
173: buffer_init(&output);
174: buffer_init(&outgoing_packet);
175: buffer_init(&incoming_packet);
176: }
177: /* Kludge: arrange the close function to be called from fatal(). */
178: fatal_add_cleanup((void (*) (void *)) packet_close, NULL);
1.1 deraadt 179: }
180:
1.19 markus 181: /* Returns 1 if remote host is connected via socket, 0 if not. */
182:
183: int
184: packet_connection_is_on_socket()
185: {
186: struct sockaddr_storage from, to;
187: socklen_t fromlen, tolen;
188:
189: /* filedescriptors in and out are the same, so it's a socket */
190: if (connection_in == connection_out)
191: return 1;
192: fromlen = sizeof(from);
193: memset(&from, 0, sizeof(from));
1.20 markus 194: if (getpeername(connection_in, (struct sockaddr *)&from, &fromlen) < 0)
1.19 markus 195: return 0;
196: tolen = sizeof(to);
197: memset(&to, 0, sizeof(to));
1.20 markus 198: if (getpeername(connection_out, (struct sockaddr *)&to, &tolen) < 0)
1.19 markus 199: return 0;
200: if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0)
201: return 0;
202: if (from.ss_family != AF_INET && from.ss_family != AF_INET6)
203: return 0;
204: return 1;
205: }
206:
207: /* returns 1 if connection is via ipv4 */
208:
209: int
210: packet_connection_is_ipv4()
211: {
212: struct sockaddr_storage to;
1.21 deraadt 213: socklen_t tolen = sizeof(to);
1.19 markus 214:
215: memset(&to, 0, sizeof(to));
216: if (getsockname(connection_out, (struct sockaddr *)&to, &tolen) < 0)
217: return 0;
218: if (to.ss_family != AF_INET)
219: return 0;
220: return 1;
221: }
222:
1.1 deraadt 223: /* Sets the connection into non-blocking mode. */
224:
1.2 provos 225: void
226: packet_set_nonblocking()
1.1 deraadt 227: {
1.14 markus 228: /* Set the socket into non-blocking mode. */
229: if (fcntl(connection_in, F_SETFL, O_NONBLOCK) < 0)
230: error("fcntl O_NONBLOCK: %.100s", strerror(errno));
231:
232: if (connection_out != connection_in) {
233: if (fcntl(connection_out, F_SETFL, O_NONBLOCK) < 0)
234: error("fcntl O_NONBLOCK: %.100s", strerror(errno));
235: }
1.1 deraadt 236: }
237:
238: /* Returns the socket used for reading. */
239:
1.2 provos 240: int
241: packet_get_connection_in()
1.1 deraadt 242: {
1.14 markus 243: return connection_in;
1.1 deraadt 244: }
245:
246: /* Returns the descriptor used for writing. */
247:
1.2 provos 248: int
249: packet_get_connection_out()
1.1 deraadt 250: {
1.14 markus 251: return connection_out;
1.1 deraadt 252: }
253:
254: /* Closes the connection and clears and frees internal data structures. */
255:
1.2 provos 256: void
257: packet_close()
1.1 deraadt 258: {
1.14 markus 259: if (!initialized)
260: return;
261: initialized = 0;
262: if (connection_in == connection_out) {
263: shutdown(connection_out, SHUT_RDWR);
264: close(connection_out);
265: } else {
266: close(connection_in);
267: close(connection_out);
268: }
269: buffer_free(&input);
270: buffer_free(&output);
271: buffer_free(&outgoing_packet);
272: buffer_free(&incoming_packet);
273: if (packet_compression) {
274: buffer_free(&compression_buffer);
275: buffer_compress_uninit();
276: }
1.1 deraadt 277: }
278:
279: /* Sets remote side protocol flags. */
280:
1.2 provos 281: void
1.40 markus 282: packet_set_protocol_flags(u_int protocol_flags)
1.1 deraadt 283: {
1.14 markus 284: remote_protocol_flags = protocol_flags;
285: channel_set_options((protocol_flags & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) != 0);
1.1 deraadt 286: }
287:
288: /* Returns the remote protocol flags set earlier by the above function. */
289:
1.40 markus 290: u_int
1.2 provos 291: packet_get_protocol_flags()
1.1 deraadt 292: {
1.14 markus 293: return remote_protocol_flags;
1.1 deraadt 294: }
295:
1.16 markus 296: /*
297: * Starts packet compression from the next packet on in both directions.
298: * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip.
299: */
1.1 deraadt 300:
1.25 markus 301: /*** XXXXX todo: kex means re-init */
1.2 provos 302: void
303: packet_start_compression(int level)
1.1 deraadt 304: {
1.14 markus 305: if (packet_compression)
306: fatal("Compression already enabled.");
307: packet_compression = 1;
308: buffer_init(&compression_buffer);
309: buffer_compress_init(level);
1.1 deraadt 310: }
311:
1.16 markus 312: /*
313: * Encrypts the given number of bytes, copying from src to dest. bytes is
314: * known to be a multiple of 8.
315: */
1.1 deraadt 316:
1.2 provos 317: void
1.14 markus 318: packet_encrypt(CipherContext * cc, void *dest, void *src,
1.40 markus 319: u_int bytes)
1.1 deraadt 320: {
1.14 markus 321: cipher_encrypt(cc, dest, src, bytes);
1.1 deraadt 322: }
323:
1.16 markus 324: /*
325: * Decrypts the given number of bytes, copying from src to dest. bytes is
326: * known to be a multiple of 8.
327: */
1.1 deraadt 328:
1.2 provos 329: void
1.40 markus 330: packet_decrypt(CipherContext *context, void *dest, void *src, u_int bytes)
1.1 deraadt 331: {
1.16 markus 332: /*
333: * Cryptographic attack detector for ssh - Modifications for packet.c
334: * (C)1998 CORE-SDI, Buenos Aires Argentina Ariel Futoransky(futo@core-sdi.com)
335: */
1.37 markus 336: if (!compat20 &&
337: context->cipher->number != SSH_CIPHER_NONE &&
338: detect_attack(src, bytes, NULL) == DEATTACK_DETECTED)
1.14 markus 339: packet_disconnect("crc32 compensation attack: network attack detected");
340:
1.37 markus 341: cipher_decrypt(context, dest, src, bytes);
1.1 deraadt 342: }
343:
1.16 markus 344: /*
345: * Causes any further packets to be encrypted using the given key. The same
346: * key is used for both sending and reception. However, both directions are
347: * encrypted independently of each other.
348: */
1.1 deraadt 349:
1.2 provos 350: void
1.40 markus 351: packet_set_encryption_key(const u_char *key, u_int keylen,
1.37 markus 352: int number)
1.1 deraadt 353: {
1.37 markus 354: Cipher *cipher = cipher_by_number(number);
355: if (cipher == NULL)
356: fatal("packet_set_encryption_key: unknown cipher number %d", number);
1.25 markus 357: if (keylen < 20)
1.37 markus 358: fatal("packet_set_encryption_key: keylen too small: %d", keylen);
359: cipher_init(&receive_context, cipher, key, keylen, NULL, 0);
360: cipher_init(&send_context, cipher, key, keylen, NULL, 0);
1.1 deraadt 361: }
362:
363: /* Starts constructing a packet to send. */
364:
1.2 provos 365: void
1.25 markus 366: packet_start1(int type)
1.1 deraadt 367: {
1.14 markus 368: char buf[9];
1.1 deraadt 369:
1.14 markus 370: buffer_clear(&outgoing_packet);
371: memset(buf, 0, 8);
372: buf[8] = type;
373: buffer_append(&outgoing_packet, buf, 9);
1.1 deraadt 374: }
375:
1.25 markus 376: void
377: packet_start2(int type)
378: {
379: char buf[4+1+1];
380:
381: buffer_clear(&outgoing_packet);
382: memset(buf, 0, sizeof buf);
383: /* buf[0..3] = payload_len; */
384: /* buf[4] = pad_len; */
385: buf[5] = type & 0xff;
386: buffer_append(&outgoing_packet, buf, sizeof buf);
387: }
388:
389: void
390: packet_start(int type)
391: {
392: DBG(debug("packet_start[%d]",type));
393: if (use_ssh2_packet_format)
394: packet_start2(type);
395: else
396: packet_start1(type);
397: }
398:
1.1 deraadt 399: /* Appends a character to the packet data. */
400:
1.2 provos 401: void
402: packet_put_char(int value)
1.1 deraadt 403: {
1.14 markus 404: char ch = value;
405: buffer_append(&outgoing_packet, &ch, 1);
1.1 deraadt 406: }
407:
408: /* Appends an integer to the packet data. */
409:
1.2 provos 410: void
1.40 markus 411: packet_put_int(u_int value)
1.1 deraadt 412: {
1.14 markus 413: buffer_put_int(&outgoing_packet, value);
1.1 deraadt 414: }
415:
416: /* Appends a string to packet data. */
417:
1.2 provos 418: void
1.40 markus 419: packet_put_string(const char *buf, u_int len)
1.1 deraadt 420: {
1.14 markus 421: buffer_put_string(&outgoing_packet, buf, len);
1.1 deraadt 422: }
1.24 markus 423: void
424: packet_put_cstring(const char *str)
425: {
426: buffer_put_string(&outgoing_packet, str, strlen(str));
427: }
428:
429: void
1.40 markus 430: packet_put_raw(const char *buf, u_int len)
1.24 markus 431: {
432: buffer_append(&outgoing_packet, buf, len);
433: }
434:
1.1 deraadt 435:
436: /* Appends an arbitrary precision integer to packet data. */
437:
1.2 provos 438: void
1.14 markus 439: packet_put_bignum(BIGNUM * value)
1.1 deraadt 440: {
1.14 markus 441: buffer_put_bignum(&outgoing_packet, value);
1.1 deraadt 442: }
1.24 markus 443: void
444: packet_put_bignum2(BIGNUM * value)
445: {
446: buffer_put_bignum2(&outgoing_packet, value);
447: }
1.1 deraadt 448:
1.16 markus 449: /*
450: * Finalizes and sends the packet. If the encryption key has been set,
451: * encrypts the packet before sending.
452: */
1.14 markus 453:
1.2 provos 454: void
1.49 itojun 455: packet_send1(void)
1.1 deraadt 456: {
1.14 markus 457: char buf[8], *cp;
458: int i, padding, len;
1.40 markus 459: u_int checksum;
1.14 markus 460: u_int32_t rand = 0;
461:
1.16 markus 462: /*
463: * If using packet compression, compress the payload of the outgoing
464: * packet.
465: */
1.14 markus 466: if (packet_compression) {
467: buffer_clear(&compression_buffer);
468: /* Skip padding. */
469: buffer_consume(&outgoing_packet, 8);
470: /* padding */
471: buffer_append(&compression_buffer, "\0\0\0\0\0\0\0\0", 8);
472: buffer_compress(&outgoing_packet, &compression_buffer);
473: buffer_clear(&outgoing_packet);
474: buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer),
475: buffer_len(&compression_buffer));
476: }
477: /* Compute packet length without padding (add checksum, remove padding). */
478: len = buffer_len(&outgoing_packet) + 4 - 8;
479:
1.32 markus 480: /* Insert padding. Initialized to zero in packet_start1() */
1.14 markus 481: padding = 8 - len % 8;
482: if (cipher_type != SSH_CIPHER_NONE) {
483: cp = buffer_ptr(&outgoing_packet);
484: for (i = 0; i < padding; i++) {
485: if (i % 4 == 0)
486: rand = arc4random();
487: cp[7 - i] = rand & 0xff;
488: rand >>= 8;
489: }
490: }
491: buffer_consume(&outgoing_packet, 8 - padding);
492:
493: /* Add check bytes. */
1.40 markus 494: checksum = ssh_crc32((u_char *) buffer_ptr(&outgoing_packet),
1.34 deraadt 495: buffer_len(&outgoing_packet));
1.14 markus 496: PUT_32BIT(buf, checksum);
497: buffer_append(&outgoing_packet, buf, 4);
1.1 deraadt 498:
499: #ifdef PACKET_DEBUG
1.14 markus 500: fprintf(stderr, "packet_send plain: ");
501: buffer_dump(&outgoing_packet);
1.1 deraadt 502: #endif
503:
1.14 markus 504: /* Append to output. */
505: PUT_32BIT(buf, len);
506: buffer_append(&output, buf, 4);
507: buffer_append_space(&output, &cp, buffer_len(&outgoing_packet));
508: packet_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet),
509: buffer_len(&outgoing_packet));
510:
1.1 deraadt 511: #ifdef PACKET_DEBUG
1.14 markus 512: fprintf(stderr, "encrypted: ");
513: buffer_dump(&output);
1.1 deraadt 514: #endif
515:
1.14 markus 516: buffer_clear(&outgoing_packet);
1.1 deraadt 517:
1.16 markus 518: /*
519: * Note that the packet is now only buffered in output. It won\'t be
520: * actually sent until packet_write_wait or packet_write_poll is
521: * called.
522: */
1.1 deraadt 523: }
524:
1.16 markus 525: /*
1.25 markus 526: * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue)
527: */
528: void
1.49 itojun 529: packet_send2(void)
1.25 markus 530: {
1.50 markus 531: static u_int32_t seqnr = 0;
1.40 markus 532: u_char *macbuf = NULL;
1.25 markus 533: char *cp;
1.40 markus 534: u_int packet_length = 0;
535: u_int i, padlen, len;
1.25 markus 536: u_int32_t rand = 0;
537: int type;
538: Enc *enc = NULL;
539: Mac *mac = NULL;
540: Comp *comp = NULL;
541: int block_size;
542:
543: if (kex != NULL) {
544: enc = &kex->enc[MODE_OUT];
545: mac = &kex->mac[MODE_OUT];
546: comp = &kex->comp[MODE_OUT];
547: }
1.37 markus 548: block_size = enc ? enc->cipher->block_size : 8;
1.25 markus 549:
550: cp = buffer_ptr(&outgoing_packet);
551: type = cp[5] & 0xff;
552:
553: #ifdef PACKET_DEBUG
554: fprintf(stderr, "plain: ");
555: buffer_dump(&outgoing_packet);
556: #endif
557:
558: if (comp && comp->enabled) {
559: len = buffer_len(&outgoing_packet);
560: /* skip header, compress only payload */
561: buffer_consume(&outgoing_packet, 5);
562: buffer_clear(&compression_buffer);
563: buffer_compress(&outgoing_packet, &compression_buffer);
564: buffer_clear(&outgoing_packet);
565: buffer_append(&outgoing_packet, "\0\0\0\0\0", 5);
566: buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer),
567: buffer_len(&compression_buffer));
568: DBG(debug("compression: raw %d compressed %d", len,
569: buffer_len(&outgoing_packet)));
570: }
571:
572: /* sizeof (packet_len + pad_len + payload) */
573: len = buffer_len(&outgoing_packet);
574:
575: /*
576: * calc size of padding, alloc space, get random data,
577: * minimum padding is 4 bytes
578: */
579: padlen = block_size - (len % block_size);
580: if (padlen < 4)
581: padlen += block_size;
582: buffer_append_space(&outgoing_packet, &cp, padlen);
1.38 markus 583: if (enc && enc->cipher->number != SSH_CIPHER_NONE) {
1.32 markus 584: /* random padding */
1.25 markus 585: for (i = 0; i < padlen; i++) {
586: if (i % 4 == 0)
587: rand = arc4random();
588: cp[i] = rand & 0xff;
1.52 markus 589: rand >>= 8;
1.25 markus 590: }
1.32 markus 591: } else {
592: /* clear padding */
593: memset(cp, 0, padlen);
1.25 markus 594: }
595: /* packet_length includes payload, padding and padding length field */
596: packet_length = buffer_len(&outgoing_packet) - 4;
597: cp = buffer_ptr(&outgoing_packet);
598: PUT_32BIT(cp, packet_length);
599: cp[4] = padlen & 0xff;
600: DBG(debug("send: len %d (includes padlen %d)", packet_length+4, padlen));
601:
602: /* compute MAC over seqnr and packet(length fields, payload, padding) */
603: if (mac && mac->enabled) {
1.50 markus 604: macbuf = mac_compute(mac, seqnr,
1.40 markus 605: (u_char *) buffer_ptr(&outgoing_packet),
1.50 markus 606: buffer_len(&outgoing_packet));
1.36 markus 607: DBG(debug("done calc MAC out #%d", seqnr));
1.25 markus 608: }
609: /* encrypt packet and append to output buffer. */
610: buffer_append_space(&output, &cp, buffer_len(&outgoing_packet));
611: packet_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet),
612: buffer_len(&outgoing_packet));
613: /* append unencrypted MAC */
614: if (mac && mac->enabled)
615: buffer_append(&output, (char *)macbuf, mac->mac_len);
616: #ifdef PACKET_DEBUG
617: fprintf(stderr, "encrypted: ");
618: buffer_dump(&output);
619: #endif
1.29 markus 620: /* increment sequence number for outgoing packets */
621: if (++seqnr == 0)
622: log("outgoing seqnr wraps around");
1.25 markus 623: buffer_clear(&outgoing_packet);
624:
625: if (type == SSH2_MSG_NEWKEYS) {
626: if (kex==NULL || mac==NULL || enc==NULL || comp==NULL)
627: fatal("packet_send2: no KEX");
628: if (mac->md != NULL)
629: mac->enabled = 1;
1.37 markus 630: DBG(debug("cipher_init send_context"));
631: cipher_init(&send_context, enc->cipher,
632: enc->key, enc->cipher->key_len,
633: enc->iv, enc->cipher->block_size);
1.25 markus 634: clear_enc_keys(enc, kex->we_need);
635: if (comp->type != 0 && comp->enabled == 0) {
636: comp->enabled = 1;
637: if (! packet_compression)
638: packet_start_compression(6);
639: }
640: }
641: }
642:
643: void
644: packet_send()
645: {
646: if (use_ssh2_packet_format)
647: packet_send2();
648: else
649: packet_send1();
650: DBG(debug("packet_send done"));
651: }
652:
653: /*
1.16 markus 654: * Waits until a packet has been received, and returns its type. Note that
655: * no other data is processed until this returns, so this function should not
656: * be used during the interactive session.
657: */
1.1 deraadt 658:
1.2 provos 659: int
660: packet_read(int *payload_len_ptr)
1.1 deraadt 661: {
1.14 markus 662: int type, len;
663: fd_set set;
664: char buf[8192];
1.25 markus 665: DBG(debug("packet_read()"));
1.14 markus 666:
667: /* Since we are blocking, ensure that all written packets have been sent. */
668: packet_write_wait();
669:
670: /* Stay in the loop until we have received a complete packet. */
671: for (;;) {
672: /* Try to read a packet from the buffer. */
673: type = packet_read_poll(payload_len_ptr);
1.32 markus 674: if (!use_ssh2_packet_format && (
675: type == SSH_SMSG_SUCCESS
1.14 markus 676: || type == SSH_SMSG_FAILURE
677: || type == SSH_CMSG_EOF
1.32 markus 678: || type == SSH_CMSG_EXIT_CONFIRMATION))
1.14 markus 679: packet_integrity_check(*payload_len_ptr, 0, type);
680: /* If we got a packet, return it. */
681: if (type != SSH_MSG_NONE)
682: return type;
1.16 markus 683: /*
684: * Otherwise, wait for some data to arrive, add it to the
685: * buffer, and try again.
686: */
1.14 markus 687: FD_ZERO(&set);
688: FD_SET(connection_in, &set);
1.16 markus 689:
1.14 markus 690: /* Wait for some data to arrive. */
1.51 deraadt 691: while (select(connection_in + 1, &set, NULL, NULL, NULL) == -1 &&
692: (errno == EAGAIN || errno == EINTR))
693: ;
1.16 markus 694:
1.14 markus 695: /* Read data from the socket. */
696: len = read(connection_in, buf, sizeof(buf));
1.18 markus 697: if (len == 0) {
698: log("Connection closed by %.200s", get_remote_ipaddr());
699: fatal_cleanup();
700: }
1.14 markus 701: if (len < 0)
702: fatal("Read from socket failed: %.100s", strerror(errno));
703: /* Append it to the buffer. */
704: packet_process_incoming(buf, len);
705: }
706: /* NOTREACHED */
1.1 deraadt 707: }
708:
1.16 markus 709: /*
710: * Waits until a packet has been received, verifies that its type matches
711: * that given, and gives a fatal error and exits if there is a mismatch.
712: */
1.1 deraadt 713:
1.2 provos 714: void
715: packet_read_expect(int *payload_len_ptr, int expected_type)
1.1 deraadt 716: {
1.14 markus 717: int type;
1.1 deraadt 718:
1.14 markus 719: type = packet_read(payload_len_ptr);
720: if (type != expected_type)
721: packet_disconnect("Protocol error: expected packet type %d, got %d",
1.25 markus 722: expected_type, type);
1.1 deraadt 723: }
724:
725: /* Checks if a full packet is available in the data received so far via
1.14 markus 726: * packet_process_incoming. If so, reads the packet; otherwise returns
727: * SSH_MSG_NONE. This does not wait for data from the connection.
728: *
729: * SSH_MSG_DISCONNECT is handled specially here. Also,
730: * SSH_MSG_IGNORE messages are skipped by this function and are never returned
731: * to higher levels.
732: *
733: * The returned payload_len does include space consumed by:
734: * Packet length
735: * Padding
736: * Packet type
737: * Check bytes
738: */
1.1 deraadt 739:
1.2 provos 740: int
1.25 markus 741: packet_read_poll1(int *payload_len_ptr)
1.1 deraadt 742: {
1.40 markus 743: u_int len, padded_len;
744: u_char *ucp;
1.25 markus 745: char buf[8], *cp;
1.40 markus 746: u_int checksum, stored_checksum;
1.14 markus 747:
748: /* Check if input size is less than minimum packet size. */
749: if (buffer_len(&input) < 4 + 8)
750: return SSH_MSG_NONE;
751: /* Get length of incoming packet. */
1.40 markus 752: ucp = (u_char *) buffer_ptr(&input);
1.14 markus 753: len = GET_32BIT(ucp);
754: if (len < 1 + 2 + 2 || len > 256 * 1024)
755: packet_disconnect("Bad packet length %d.", len);
756: padded_len = (len + 8) & ~7;
757:
758: /* Check if the packet has been entirely received. */
759: if (buffer_len(&input) < 4 + padded_len)
760: return SSH_MSG_NONE;
761:
762: /* The entire packet is in buffer. */
763:
764: /* Consume packet length. */
765: buffer_consume(&input, 4);
766:
767: /* Copy data to incoming_packet. */
768: buffer_clear(&incoming_packet);
769: buffer_append_space(&incoming_packet, &cp, padded_len);
770: packet_decrypt(&receive_context, cp, buffer_ptr(&input), padded_len);
771: buffer_consume(&input, padded_len);
1.1 deraadt 772:
773: #ifdef PACKET_DEBUG
1.14 markus 774: fprintf(stderr, "read_poll plain: ");
775: buffer_dump(&incoming_packet);
1.1 deraadt 776: #endif
777:
1.14 markus 778: /* Compute packet checksum. */
1.40 markus 779: checksum = ssh_crc32((u_char *) buffer_ptr(&incoming_packet),
1.25 markus 780: buffer_len(&incoming_packet) - 4);
1.14 markus 781:
782: /* Skip padding. */
783: buffer_consume(&incoming_packet, 8 - len % 8);
784:
785: /* Test check bytes. */
786:
787: if (len != buffer_len(&incoming_packet))
788: packet_disconnect("packet_read_poll: len %d != buffer_len %d.",
1.25 markus 789: len, buffer_len(&incoming_packet));
1.14 markus 790:
1.40 markus 791: ucp = (u_char *) buffer_ptr(&incoming_packet) + len - 4;
1.14 markus 792: stored_checksum = GET_32BIT(ucp);
793: if (checksum != stored_checksum)
794: packet_disconnect("Corrupted check bytes on input.");
795: buffer_consume_end(&incoming_packet, 4);
796:
797: /* If using packet compression, decompress the packet. */
798: if (packet_compression) {
799: buffer_clear(&compression_buffer);
800: buffer_uncompress(&incoming_packet, &compression_buffer);
801: buffer_clear(&incoming_packet);
802: buffer_append(&incoming_packet, buffer_ptr(&compression_buffer),
1.25 markus 803: buffer_len(&compression_buffer));
1.14 markus 804: }
805: /* Get packet type. */
806: buffer_get(&incoming_packet, &buf[0], 1);
807:
808: /* Return length of payload (without type field). */
809: *payload_len_ptr = buffer_len(&incoming_packet);
810:
811: /* Return type. */
1.40 markus 812: return (u_char) buf[0];
1.1 deraadt 813: }
1.14 markus 814:
1.25 markus 815: int
816: packet_read_poll2(int *payload_len_ptr)
817: {
1.50 markus 818: static u_int32_t seqnr = 0;
819: static u_int packet_length = 0;
1.40 markus 820: u_int padlen, need;
821: u_char buf[8], *macbuf;
822: u_char *ucp;
1.25 markus 823: char *cp;
824: int type;
825: int maclen, block_size;
826: Enc *enc = NULL;
827: Mac *mac = NULL;
828: Comp *comp = NULL;
829:
830: if (kex != NULL) {
831: enc = &kex->enc[MODE_IN];
832: mac = &kex->mac[MODE_IN];
833: comp = &kex->comp[MODE_IN];
834: }
835: maclen = mac && mac->enabled ? mac->mac_len : 0;
1.37 markus 836: block_size = enc ? enc->cipher->block_size : 8;
1.25 markus 837:
838: if (packet_length == 0) {
839: /*
840: * check if input size is less than the cipher block size,
841: * decrypt first block and extract length of incoming packet
842: */
843: if (buffer_len(&input) < block_size)
844: return SSH_MSG_NONE;
845: buffer_clear(&incoming_packet);
846: buffer_append_space(&incoming_packet, &cp, block_size);
847: packet_decrypt(&receive_context, cp, buffer_ptr(&input),
848: block_size);
1.40 markus 849: ucp = (u_char *) buffer_ptr(&incoming_packet);
1.25 markus 850: packet_length = GET_32BIT(ucp);
851: if (packet_length < 1 + 4 || packet_length > 256 * 1024) {
852: buffer_dump(&incoming_packet);
853: packet_disconnect("Bad packet length %d.", packet_length);
854: }
855: DBG(debug("input: packet len %d", packet_length+4));
856: buffer_consume(&input, block_size);
857: }
858: /* we have a partial packet of block_size bytes */
859: need = 4 + packet_length - block_size;
860: DBG(debug("partial packet %d, need %d, maclen %d", block_size,
861: need, maclen));
862: if (need % block_size != 0)
863: fatal("padding error: need %d block %d mod %d",
864: need, block_size, need % block_size);
865: /*
866: * check if the entire packet has been received and
867: * decrypt into incoming_packet
868: */
869: if (buffer_len(&input) < need + maclen)
870: return SSH_MSG_NONE;
871: #ifdef PACKET_DEBUG
872: fprintf(stderr, "read_poll enc/full: ");
873: buffer_dump(&input);
874: #endif
875: buffer_append_space(&incoming_packet, &cp, need);
876: packet_decrypt(&receive_context, cp, buffer_ptr(&input), need);
877: buffer_consume(&input, need);
878: /*
879: * compute MAC over seqnr and packet,
880: * increment sequence number for incoming packet
881: */
1.29 markus 882: if (mac && mac->enabled) {
1.50 markus 883: macbuf = mac_compute(mac, seqnr,
1.40 markus 884: (u_char *) buffer_ptr(&incoming_packet),
1.50 markus 885: buffer_len(&incoming_packet));
1.25 markus 886: if (memcmp(macbuf, buffer_ptr(&input), mac->mac_len) != 0)
1.36 markus 887: packet_disconnect("Corrupted MAC on input.");
888: DBG(debug("MAC #%d ok", seqnr));
1.25 markus 889: buffer_consume(&input, mac->mac_len);
890: }
1.29 markus 891: if (++seqnr == 0)
892: log("incoming seqnr wraps around");
1.25 markus 893:
894: /* get padlen */
895: cp = buffer_ptr(&incoming_packet) + 4;
896: padlen = *cp & 0xff;
897: DBG(debug("input: padlen %d", padlen));
898: if (padlen < 4)
899: packet_disconnect("Corrupted padlen %d on input.", padlen);
900:
901: /* skip packet size + padlen, discard padding */
902: buffer_consume(&incoming_packet, 4 + 1);
903: buffer_consume_end(&incoming_packet, padlen);
904:
905: DBG(debug("input: len before de-compress %d", buffer_len(&incoming_packet)));
906: if (comp && comp->enabled) {
907: buffer_clear(&compression_buffer);
908: buffer_uncompress(&incoming_packet, &compression_buffer);
909: buffer_clear(&incoming_packet);
910: buffer_append(&incoming_packet, buffer_ptr(&compression_buffer),
911: buffer_len(&compression_buffer));
912: DBG(debug("input: len after de-compress %d", buffer_len(&incoming_packet)));
913: }
914: /*
915: * get packet type, implies consume.
916: * return length of payload (without type field)
917: */
918: buffer_get(&incoming_packet, (char *)&buf[0], 1);
919: *payload_len_ptr = buffer_len(&incoming_packet);
920:
921: /* reset for next packet */
922: packet_length = 0;
923:
924: /* extract packet type */
1.40 markus 925: type = (u_char)buf[0];
1.25 markus 926:
927: if (type == SSH2_MSG_NEWKEYS) {
928: if (kex==NULL || mac==NULL || enc==NULL || comp==NULL)
929: fatal("packet_read_poll2: no KEX");
930: if (mac->md != NULL)
931: mac->enabled = 1;
1.37 markus 932: DBG(debug("cipher_init receive_context"));
933: cipher_init(&receive_context, enc->cipher,
934: enc->key, enc->cipher->key_len,
935: enc->iv, enc->cipher->block_size);
1.25 markus 936: clear_enc_keys(enc, kex->we_need);
937: if (comp->type != 0 && comp->enabled == 0) {
938: comp->enabled = 1;
939: if (! packet_compression)
940: packet_start_compression(6);
941: }
942: }
943:
944: #ifdef PACKET_DEBUG
945: fprintf(stderr, "read/plain[%d]:\r\n",type);
946: buffer_dump(&incoming_packet);
947: #endif
1.40 markus 948: return (u_char)type;
1.25 markus 949: }
950:
951: int
952: packet_read_poll(int *payload_len_ptr)
953: {
954: char *msg;
955: for (;;) {
956: int type = use_ssh2_packet_format ?
957: packet_read_poll2(payload_len_ptr):
958: packet_read_poll1(payload_len_ptr);
959:
960: if(compat20) {
961: int reason;
962: if (type != 0)
963: DBG(debug("received packet type %d", type));
964: switch(type) {
965: case SSH2_MSG_IGNORE:
966: break;
967: case SSH2_MSG_DEBUG:
968: packet_get_char();
969: msg = packet_get_string(NULL);
970: debug("Remote: %.900s", msg);
971: xfree(msg);
972: msg = packet_get_string(NULL);
973: xfree(msg);
974: break;
975: case SSH2_MSG_DISCONNECT:
976: reason = packet_get_int();
977: msg = packet_get_string(NULL);
1.41 markus 978: log("Received disconnect from %s: %d: %.400s", get_remote_ipaddr(),
979: reason, msg);
1.25 markus 980: xfree(msg);
981: fatal_cleanup();
982: break;
983: default:
984: return type;
985: break;
1.48 stevesk 986: }
1.25 markus 987: } else {
988: switch(type) {
989: case SSH_MSG_IGNORE:
990: break;
991: case SSH_MSG_DEBUG:
992: msg = packet_get_string(NULL);
993: debug("Remote: %.900s", msg);
994: xfree(msg);
995: break;
996: case SSH_MSG_DISCONNECT:
997: msg = packet_get_string(NULL);
1.41 markus 998: log("Received disconnect from %s: %.400s", get_remote_ipaddr(),
999: msg);
1.25 markus 1000: fatal_cleanup();
1001: xfree(msg);
1002: break;
1003: default:
1004: if (type != 0)
1005: DBG(debug("received packet type %d", type));
1006: return type;
1007: break;
1.48 stevesk 1008: }
1.25 markus 1009: }
1010: }
1011: }
1012:
1.16 markus 1013: /*
1014: * Buffers the given amount of input characters. This is intended to be used
1015: * together with packet_read_poll.
1016: */
1.1 deraadt 1017:
1.2 provos 1018: void
1.40 markus 1019: packet_process_incoming(const char *buf, u_int len)
1.1 deraadt 1020: {
1.14 markus 1021: buffer_append(&input, buf, len);
1.1 deraadt 1022: }
1023:
1024: /* Returns a character from the packet. */
1025:
1.40 markus 1026: u_int
1.2 provos 1027: packet_get_char()
1.1 deraadt 1028: {
1.14 markus 1029: char ch;
1030: buffer_get(&incoming_packet, &ch, 1);
1.40 markus 1031: return (u_char) ch;
1.1 deraadt 1032: }
1033:
1034: /* Returns an integer from the packet data. */
1035:
1.40 markus 1036: u_int
1.2 provos 1037: packet_get_int()
1.1 deraadt 1038: {
1.14 markus 1039: return buffer_get_int(&incoming_packet);
1.1 deraadt 1040: }
1041:
1.16 markus 1042: /*
1043: * Returns an arbitrary precision integer from the packet data. The integer
1044: * must have been initialized before this call.
1045: */
1.1 deraadt 1046:
1.2 provos 1047: void
1.14 markus 1048: packet_get_bignum(BIGNUM * value, int *length_ptr)
1.1 deraadt 1049: {
1.14 markus 1050: *length_ptr = buffer_get_bignum(&incoming_packet, value);
1.24 markus 1051: }
1052:
1053: void
1054: packet_get_bignum2(BIGNUM * value, int *length_ptr)
1055: {
1056: *length_ptr = buffer_get_bignum2(&incoming_packet, value);
1057: }
1058:
1059: char *
1060: packet_get_raw(int *length_ptr)
1061: {
1062: int bytes = buffer_len(&incoming_packet);
1063: if (length_ptr != NULL)
1064: *length_ptr = bytes;
1065: return buffer_ptr(&incoming_packet);
1.28 markus 1066: }
1067:
1068: int
1069: packet_remaining(void)
1070: {
1071: return buffer_len(&incoming_packet);
1.1 deraadt 1072: }
1073:
1.16 markus 1074: /*
1075: * Returns a string from the packet data. The string is allocated using
1076: * xmalloc; it is the responsibility of the calling program to free it when
1077: * no longer needed. The length_ptr argument may be NULL, or point to an
1078: * integer into which the length of the string is stored.
1079: */
1.1 deraadt 1080:
1.16 markus 1081: char *
1.40 markus 1082: packet_get_string(u_int *length_ptr)
1.1 deraadt 1083: {
1.14 markus 1084: return buffer_get_string(&incoming_packet, length_ptr);
1.1 deraadt 1085: }
1086:
1.16 markus 1087: /*
1088: * Sends a diagnostic message from the server to the client. This message
1089: * can be sent at any time (but not while constructing another message). The
1090: * message is printed immediately, but only if the client is being executed
1091: * in verbose mode. These messages are primarily intended to ease debugging
1092: * authentication problems. The length of the formatted message must not
1093: * exceed 1024 bytes. This will automatically call packet_write_wait.
1094: */
1.1 deraadt 1095:
1.2 provos 1096: void
1.14 markus 1097: packet_send_debug(const char *fmt,...)
1.1 deraadt 1098: {
1.14 markus 1099: char buf[1024];
1100: va_list args;
1.39 markus 1101:
1102: if (compat20 && (datafellows & SSH_BUG_DEBUG))
1103: return;
1.14 markus 1104:
1105: va_start(args, fmt);
1106: vsnprintf(buf, sizeof(buf), fmt, args);
1107: va_end(args);
1108:
1.30 markus 1109: if (compat20) {
1110: packet_start(SSH2_MSG_DEBUG);
1111: packet_put_char(0); /* bool: always display */
1112: packet_put_cstring(buf);
1113: packet_put_cstring("");
1114: } else {
1115: packet_start(SSH_MSG_DEBUG);
1116: packet_put_cstring(buf);
1117: }
1.14 markus 1118: packet_send();
1119: packet_write_wait();
1.1 deraadt 1120: }
1121:
1.16 markus 1122: /*
1123: * Logs the error plus constructs and sends a disconnect packet, closes the
1124: * connection, and exits. This function never returns. The error message
1125: * should not contain a newline. The length of the formatted message must
1126: * not exceed 1024 bytes.
1127: */
1.1 deraadt 1128:
1.2 provos 1129: void
1.14 markus 1130: packet_disconnect(const char *fmt,...)
1.1 deraadt 1131: {
1.14 markus 1132: char buf[1024];
1133: va_list args;
1134: static int disconnecting = 0;
1135: if (disconnecting) /* Guard against recursive invocations. */
1136: fatal("packet_disconnect called recursively.");
1137: disconnecting = 1;
1138:
1.16 markus 1139: /*
1140: * Format the message. Note that the caller must make sure the
1141: * message is of limited size.
1142: */
1.14 markus 1143: va_start(args, fmt);
1144: vsnprintf(buf, sizeof(buf), fmt, args);
1145: va_end(args);
1146:
1147: /* Send the disconnect message to the other side, and wait for it to get sent. */
1.25 markus 1148: if (compat20) {
1149: packet_start(SSH2_MSG_DISCONNECT);
1150: packet_put_int(SSH2_DISCONNECT_PROTOCOL_ERROR);
1151: packet_put_cstring(buf);
1152: packet_put_cstring("");
1153: } else {
1154: packet_start(SSH_MSG_DISCONNECT);
1155: packet_put_string(buf, strlen(buf));
1156: }
1.14 markus 1157: packet_send();
1158: packet_write_wait();
1159:
1160: /* Stop listening for connections. */
1161: channel_stop_listening();
1162:
1163: /* Close the connection. */
1164: packet_close();
1.1 deraadt 1165:
1.14 markus 1166: /* Display the error locally and exit. */
1.17 markus 1167: log("Disconnecting: %.100s", buf);
1168: fatal_cleanup();
1.1 deraadt 1169: }
1170:
1.16 markus 1171: /* Checks if there is any buffered output, and tries to write some of the output. */
1.1 deraadt 1172:
1.2 provos 1173: void
1174: packet_write_poll()
1.1 deraadt 1175: {
1.14 markus 1176: int len = buffer_len(&output);
1177: if (len > 0) {
1178: len = write(connection_out, buffer_ptr(&output), len);
1179: if (len <= 0) {
1180: if (errno == EAGAIN)
1181: return;
1182: else
1183: fatal("Write failed: %.100s", strerror(errno));
1184: }
1185: buffer_consume(&output, len);
1186: }
1.1 deraadt 1187: }
1188:
1.16 markus 1189: /*
1190: * Calls packet_write_poll repeatedly until all pending output data has been
1191: * written.
1192: */
1.1 deraadt 1193:
1.2 provos 1194: void
1195: packet_write_wait()
1.1 deraadt 1196: {
1.14 markus 1197: packet_write_poll();
1198: while (packet_have_data_to_write()) {
1199: fd_set set;
1.51 deraadt 1200:
1.14 markus 1201: FD_ZERO(&set);
1202: FD_SET(connection_out, &set);
1.51 deraadt 1203: while (select(connection_out + 1, NULL, &set, NULL, NULL) == -1 &&
1204: (errno == EAGAIN || errno == EINTR))
1205: ;
1.14 markus 1206: packet_write_poll();
1207: }
1.1 deraadt 1208: }
1209:
1210: /* Returns true if there is buffered data to write to the connection. */
1211:
1.2 provos 1212: int
1213: packet_have_data_to_write()
1.1 deraadt 1214: {
1.14 markus 1215: return buffer_len(&output) != 0;
1.1 deraadt 1216: }
1217:
1218: /* Returns true if there is not too much data to write to the connection. */
1219:
1.2 provos 1220: int
1221: packet_not_very_much_data_to_write()
1.1 deraadt 1222: {
1.14 markus 1223: if (interactive_mode)
1224: return buffer_len(&output) < 16384;
1225: else
1226: return buffer_len(&output) < 128 * 1024;
1.1 deraadt 1227: }
1228:
1229: /* Informs that the current session is interactive. Sets IP flags for that. */
1230:
1.2 provos 1231: void
1.43 markus 1232: packet_set_interactive(int interactive)
1.1 deraadt 1233: {
1.43 markus 1234: static int called = 0;
1.44 markus 1235: int lowdelay = IPTOS_LOWDELAY;
1236: int throughput = IPTOS_THROUGHPUT;
1237: int on = 1;
1238:
1.43 markus 1239: if (called)
1240: return;
1241: called = 1;
1.1 deraadt 1242:
1.14 markus 1243: /* Record that we are in interactive mode. */
1244: interactive_mode = interactive;
1.1 deraadt 1245:
1.19 markus 1246: /* Only set socket options if using a socket. */
1247: if (!packet_connection_is_on_socket())
1.14 markus 1248: return;
1.19 markus 1249: /*
1.42 markus 1250: * IPTOS_LOWDELAY and IPTOS_THROUGHPUT are IPv4 only
1.19 markus 1251: */
1.14 markus 1252: if (interactive) {
1.16 markus 1253: /*
1254: * Set IP options for an interactive connection. Use
1255: * IPTOS_LOWDELAY and TCP_NODELAY.
1256: */
1.42 markus 1257: if (packet_connection_is_ipv4()) {
1258: if (setsockopt(connection_in, IPPROTO_IP, IP_TOS,
1259: (void *) &lowdelay, sizeof(lowdelay)) < 0)
1260: error("setsockopt IPTOS_LOWDELAY: %.100s",
1261: strerror(errno));
1262: }
1.14 markus 1263: if (setsockopt(connection_in, IPPROTO_TCP, TCP_NODELAY, (void *) &on,
1.19 markus 1264: sizeof(on)) < 0)
1.14 markus 1265: error("setsockopt TCP_NODELAY: %.100s", strerror(errno));
1.42 markus 1266: } else if (packet_connection_is_ipv4()) {
1.16 markus 1267: /*
1268: * Set IP options for a non-interactive connection. Use
1269: * IPTOS_THROUGHPUT.
1270: */
1.14 markus 1271: if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, (void *) &throughput,
1.19 markus 1272: sizeof(throughput)) < 0)
1.14 markus 1273: error("setsockopt IPTOS_THROUGHPUT: %.100s", strerror(errno));
1274: }
1.1 deraadt 1275: }
1276:
1277: /* Returns true if the current connection is interactive. */
1278:
1.2 provos 1279: int
1280: packet_is_interactive()
1.1 deraadt 1281: {
1.14 markus 1282: return interactive_mode;
1.12 markus 1283: }
1284:
1285: int
1286: packet_set_maxsize(int s)
1287: {
1.14 markus 1288: static int called = 0;
1289: if (called) {
1.25 markus 1290: log("packet_set_maxsize: called twice: old %d new %d",
1291: max_packet_size, s);
1.14 markus 1292: return -1;
1293: }
1294: if (s < 4 * 1024 || s > 1024 * 1024) {
1295: log("packet_set_maxsize: bad size %d", s);
1296: return -1;
1297: }
1298: log("packet_set_maxsize: setting to %d", s);
1299: max_packet_size = s;
1300: return s;
1.53 markus 1301: }
1302:
1303: /*
1304: * 9.2. Ignored Data Message
1305: *
1306: * byte SSH_MSG_IGNORE
1307: * string data
1308: *
1309: * All implementations MUST understand (and ignore) this message at any
1310: * time (after receiving the protocol version). No implementation is
1311: * required to send them. This message can be used as an additional
1312: * protection measure against advanced traffic analysis techniques.
1313: */
1314: /* size of current + ignore message should be n*sumlen bytes (w/o mac) */
1315: void
1316: packet_inject_ignore(int sumlen)
1317: {
1.54 ! markus 1318: int blocksize, padlen, have, need, nb, mini, nbytes;
1.53 markus 1319: Enc *enc = NULL;
1320:
1321: if (use_ssh2_packet_format == 0)
1322: return;
1323:
1324: have = buffer_len(&outgoing_packet);
1325: debug2("packet_inject_ignore: current %d", have);
1326: if (kex != NULL)
1327: enc = &kex->enc[MODE_OUT];
1328: blocksize = enc ? enc->cipher->block_size : 8;
1329: padlen = blocksize - (have % blocksize);
1330: if (padlen < 4)
1331: padlen += blocksize;
1332: have += padlen;
1333: have /= blocksize; /* # of blocks for current message */
1334:
1335: nb = roundup(sumlen, blocksize) / blocksize; /* blocks for both */
1336: mini = roundup(5+1+4+4, blocksize) / blocksize; /* minsize ignore msg */
1337: need = nb - (have % nb); /* blocks for ignore */
1338: if (need <= mini)
1339: need += nb;
1340: nbytes = (need - mini) * blocksize; /* size of ignore payload */
1341: debug2("packet_inject_ignore: block %d have %d nb %d mini %d need %d",
1342: blocksize, have, nb, mini, need);
1343:
1344: /* enqueue current message and append a ignore message */
1345: packet_send();
1.54 ! markus 1346: packet_send_ignore(nbytes);
! 1347: }
! 1348:
! 1349: void
! 1350: packet_send_ignore(int nbytes)
! 1351: {
! 1352: u_int32_t rand = 0;
! 1353: int i;
! 1354:
! 1355: packet_start(compat20 ? SSH2_MSG_IGNORE : SSH_MSG_IGNORE);
1.53 markus 1356: packet_put_int(nbytes);
1357: for(i = 0; i < nbytes; i++) {
1358: if (i % 4 == 0)
1359: rand = arc4random();
1360: packet_put_char(rand & 0xff);
1361: rand >>= 8;
1362: }
1.1 deraadt 1363: }
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