Annotation of src/usr.bin/ssh/packet.c, Revision 1.78
1.1 deraadt 1: /*
1.15 deraadt 2: * Author: Tatu Ylonen <ylo@cs.hut.fi>
3: * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
4: * All rights reserved
1.35 deraadt 5: * This file contains code implementing the packet protocol and communication
6: * with the other side. This same code is used both on client and server side.
1.29 markus 7: *
1.35 deraadt 8: * As far as I am concerned, the code I have written for this software
9: * can be used freely for any purpose. Any derived versions of this
10: * software must be clearly marked as such, and if the derived work is
11: * incompatible with the protocol description in the RFC file, it must be
12: * called by a name other than "ssh" or "Secure Shell".
1.29 markus 13: *
1.25 markus 14: *
15: * SSH2 packet format added by Markus Friedl.
1.69 markus 16: * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
1.25 markus 17: *
1.35 deraadt 18: * Redistribution and use in source and binary forms, with or without
19: * modification, are permitted provided that the following conditions
20: * are met:
21: * 1. Redistributions of source code must retain the above copyright
22: * notice, this list of conditions and the following disclaimer.
23: * 2. Redistributions in binary form must reproduce the above copyright
24: * notice, this list of conditions and the following disclaimer in the
25: * documentation and/or other materials provided with the distribution.
26: *
27: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
28: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
29: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
30: * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
31: * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
32: * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
33: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
34: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
35: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
36: * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1.15 deraadt 37: */
1.1 deraadt 38:
39: #include "includes.h"
1.78 ! markus 40: RCSID("$OpenBSD: packet.c,v 1.77 2001/12/20 22:50:24 djm 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"
1.64 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:
78: /* Protocol flags for the remote side. */
1.40 markus 79: static u_int remote_protocol_flags = 0;
1.1 deraadt 80:
81: /* Encryption context for receiving data. This is only used for decryption. */
82: static CipherContext receive_context;
1.14 markus 83:
84: /* Encryption context for sending data. This is only used for encryption. */
1.1 deraadt 85: static CipherContext send_context;
86:
87: /* Buffer for raw input data from the socket. */
88: static Buffer input;
89:
90: /* Buffer for raw output data going to the socket. */
91: static Buffer output;
92:
93: /* Buffer for the partial outgoing packet being constructed. */
94: static Buffer outgoing_packet;
95:
96: /* Buffer for the incoming packet currently being processed. */
97: static Buffer incoming_packet;
98:
99: /* Scratch buffer for packet compression/decompression. */
100: static Buffer compression_buffer;
1.60 markus 101: static int compression_buffer_ready = 0;
1.1 deraadt 102:
103: /* Flag indicating whether packet compression/decompression is enabled. */
104: static int packet_compression = 0;
105:
1.12 markus 106: /* default maximum packet size */
107: int max_packet_size = 32768;
108:
1.1 deraadt 109: /* Flag indicating whether this module has been initialized. */
110: static int initialized = 0;
111:
112: /* Set to true if the connection is interactive. */
113: static int interactive_mode = 0;
114:
1.25 markus 115: /* Session key information for Encryption and MAC */
1.57 markus 116: Newkeys *newkeys[MODE_MAX];
1.25 markus 117:
1.71 markus 118: /* roundup current message to extra_pad bytes */
119: static u_char extra_pad = 0;
120:
1.16 markus 121: /*
122: * Sets the descriptors used for communication. Disables encryption until
123: * packet_set_encryption_key is called.
124: */
1.2 provos 125: void
126: packet_set_connection(int fd_in, int fd_out)
1.1 deraadt 127: {
1.37 markus 128: Cipher *none = cipher_by_name("none");
129: if (none == NULL)
130: fatal("packet_set_connection: cannot load cipher 'none'");
1.14 markus 131: connection_in = fd_in;
132: connection_out = fd_out;
1.40 markus 133: cipher_init(&send_context, none, (u_char *) "", 0, NULL, 0);
134: cipher_init(&receive_context, none, (u_char *) "", 0, NULL, 0);
1.62 markus 135: newkeys[MODE_IN] = newkeys[MODE_OUT] = NULL;
1.14 markus 136: if (!initialized) {
137: initialized = 1;
138: buffer_init(&input);
139: buffer_init(&output);
140: buffer_init(&outgoing_packet);
141: buffer_init(&incoming_packet);
142: }
143: /* Kludge: arrange the close function to be called from fatal(). */
144: fatal_add_cleanup((void (*) (void *)) packet_close, NULL);
1.1 deraadt 145: }
146:
1.19 markus 147: /* Returns 1 if remote host is connected via socket, 0 if not. */
148:
149: int
1.73 itojun 150: packet_connection_is_on_socket(void)
1.19 markus 151: {
152: struct sockaddr_storage from, to;
153: socklen_t fromlen, tolen;
154:
155: /* filedescriptors in and out are the same, so it's a socket */
156: if (connection_in == connection_out)
157: return 1;
158: fromlen = sizeof(from);
159: memset(&from, 0, sizeof(from));
1.20 markus 160: if (getpeername(connection_in, (struct sockaddr *)&from, &fromlen) < 0)
1.19 markus 161: return 0;
162: tolen = sizeof(to);
163: memset(&to, 0, sizeof(to));
1.20 markus 164: if (getpeername(connection_out, (struct sockaddr *)&to, &tolen) < 0)
1.19 markus 165: return 0;
166: if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0)
167: return 0;
168: if (from.ss_family != AF_INET && from.ss_family != AF_INET6)
169: return 0;
170: return 1;
171: }
172:
173: /* returns 1 if connection is via ipv4 */
174:
175: int
1.73 itojun 176: packet_connection_is_ipv4(void)
1.19 markus 177: {
178: struct sockaddr_storage to;
1.21 deraadt 179: socklen_t tolen = sizeof(to);
1.19 markus 180:
181: memset(&to, 0, sizeof(to));
182: if (getsockname(connection_out, (struct sockaddr *)&to, &tolen) < 0)
183: return 0;
184: if (to.ss_family != AF_INET)
185: return 0;
186: return 1;
187: }
188:
1.1 deraadt 189: /* Sets the connection into non-blocking mode. */
190:
1.2 provos 191: void
1.73 itojun 192: packet_set_nonblocking(void)
1.1 deraadt 193: {
1.14 markus 194: /* Set the socket into non-blocking mode. */
195: if (fcntl(connection_in, F_SETFL, O_NONBLOCK) < 0)
196: error("fcntl O_NONBLOCK: %.100s", strerror(errno));
197:
198: if (connection_out != connection_in) {
199: if (fcntl(connection_out, F_SETFL, O_NONBLOCK) < 0)
200: error("fcntl O_NONBLOCK: %.100s", strerror(errno));
201: }
1.1 deraadt 202: }
203:
204: /* Returns the socket used for reading. */
205:
1.2 provos 206: int
1.73 itojun 207: packet_get_connection_in(void)
1.1 deraadt 208: {
1.14 markus 209: return connection_in;
1.1 deraadt 210: }
211:
212: /* Returns the descriptor used for writing. */
213:
1.2 provos 214: int
1.73 itojun 215: packet_get_connection_out(void)
1.1 deraadt 216: {
1.14 markus 217: return connection_out;
1.1 deraadt 218: }
219:
220: /* Closes the connection and clears and frees internal data structures. */
221:
1.2 provos 222: void
1.73 itojun 223: packet_close(void)
1.1 deraadt 224: {
1.14 markus 225: if (!initialized)
226: return;
227: initialized = 0;
228: if (connection_in == connection_out) {
229: shutdown(connection_out, SHUT_RDWR);
230: close(connection_out);
231: } else {
232: close(connection_in);
233: close(connection_out);
234: }
235: buffer_free(&input);
236: buffer_free(&output);
237: buffer_free(&outgoing_packet);
238: buffer_free(&incoming_packet);
1.60 markus 239: if (compression_buffer_ready) {
1.14 markus 240: buffer_free(&compression_buffer);
241: buffer_compress_uninit();
242: }
1.1 deraadt 243: }
244:
245: /* Sets remote side protocol flags. */
246:
1.2 provos 247: void
1.40 markus 248: packet_set_protocol_flags(u_int protocol_flags)
1.1 deraadt 249: {
1.14 markus 250: remote_protocol_flags = protocol_flags;
1.1 deraadt 251: }
252:
253: /* Returns the remote protocol flags set earlier by the above function. */
254:
1.40 markus 255: u_int
1.73 itojun 256: packet_get_protocol_flags(void)
1.1 deraadt 257: {
1.14 markus 258: return remote_protocol_flags;
1.1 deraadt 259: }
260:
1.16 markus 261: /*
262: * Starts packet compression from the next packet on in both directions.
263: * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip.
264: */
1.1 deraadt 265:
1.68 itojun 266: static void
267: packet_init_compression(void)
1.60 markus 268: {
269: if (compression_buffer_ready == 1)
270: return;
271: compression_buffer_ready = 1;
272: buffer_init(&compression_buffer);
273: }
274:
1.2 provos 275: void
276: packet_start_compression(int level)
1.1 deraadt 277: {
1.62 markus 278: if (packet_compression && !compat20)
1.14 markus 279: fatal("Compression already enabled.");
280: packet_compression = 1;
1.60 markus 281: packet_init_compression();
282: buffer_compress_init_send(level);
283: buffer_compress_init_recv();
1.1 deraadt 284: }
285:
1.16 markus 286: /*
287: * Causes any further packets to be encrypted using the given key. The same
288: * key is used for both sending and reception. However, both directions are
289: * encrypted independently of each other.
290: */
1.2 provos 291: void
1.40 markus 292: packet_set_encryption_key(const u_char *key, u_int keylen,
1.37 markus 293: int number)
1.1 deraadt 294: {
1.37 markus 295: Cipher *cipher = cipher_by_number(number);
296: if (cipher == NULL)
297: fatal("packet_set_encryption_key: unknown cipher number %d", number);
1.25 markus 298: if (keylen < 20)
1.37 markus 299: fatal("packet_set_encryption_key: keylen too small: %d", keylen);
300: cipher_init(&receive_context, cipher, key, keylen, NULL, 0);
301: cipher_init(&send_context, cipher, key, keylen, NULL, 0);
1.1 deraadt 302: }
303:
1.62 markus 304: /* Start constructing a packet to send. */
1.2 provos 305: void
1.62 markus 306: packet_start(u_char type)
1.1 deraadt 307: {
1.62 markus 308: u_char buf[9];
309: int len;
1.1 deraadt 310:
1.62 markus 311: DBG(debug("packet_start[%d]", type));
312: len = compat20 ? 6 : 9;
313: memset(buf, 0, len - 1);
314: buf[len - 1] = type;
1.14 markus 315: buffer_clear(&outgoing_packet);
1.62 markus 316: buffer_append(&outgoing_packet, buf, len);
1.25 markus 317: }
318:
1.62 markus 319: /* Append payload. */
1.2 provos 320: void
321: packet_put_char(int value)
1.1 deraadt 322: {
1.14 markus 323: char ch = value;
324: buffer_append(&outgoing_packet, &ch, 1);
1.1 deraadt 325: }
1.2 provos 326: void
1.40 markus 327: packet_put_int(u_int value)
1.1 deraadt 328: {
1.14 markus 329: buffer_put_int(&outgoing_packet, value);
1.1 deraadt 330: }
1.2 provos 331: void
1.76 stevesk 332: packet_put_string(const void *buf, u_int len)
1.1 deraadt 333: {
1.14 markus 334: buffer_put_string(&outgoing_packet, buf, len);
1.1 deraadt 335: }
1.24 markus 336: void
337: packet_put_cstring(const char *str)
338: {
1.65 markus 339: buffer_put_cstring(&outgoing_packet, str);
1.24 markus 340: }
341: void
1.76 stevesk 342: packet_put_raw(const void *buf, u_int len)
1.24 markus 343: {
344: buffer_append(&outgoing_packet, buf, len);
345: }
1.2 provos 346: void
1.14 markus 347: packet_put_bignum(BIGNUM * value)
1.1 deraadt 348: {
1.14 markus 349: buffer_put_bignum(&outgoing_packet, value);
1.1 deraadt 350: }
1.24 markus 351: void
352: packet_put_bignum2(BIGNUM * value)
353: {
354: buffer_put_bignum2(&outgoing_packet, value);
355: }
1.1 deraadt 356:
1.16 markus 357: /*
358: * Finalizes and sends the packet. If the encryption key has been set,
359: * encrypts the packet before sending.
360: */
1.14 markus 361:
1.68 itojun 362: static void
1.49 itojun 363: packet_send1(void)
1.1 deraadt 364: {
1.14 markus 365: char buf[8], *cp;
366: int i, padding, len;
1.40 markus 367: u_int checksum;
1.14 markus 368: u_int32_t rand = 0;
369:
1.16 markus 370: /*
371: * If using packet compression, compress the payload of the outgoing
372: * packet.
373: */
1.14 markus 374: if (packet_compression) {
375: buffer_clear(&compression_buffer);
376: /* Skip padding. */
377: buffer_consume(&outgoing_packet, 8);
378: /* padding */
379: buffer_append(&compression_buffer, "\0\0\0\0\0\0\0\0", 8);
380: buffer_compress(&outgoing_packet, &compression_buffer);
381: buffer_clear(&outgoing_packet);
382: buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer),
1.75 deraadt 383: buffer_len(&compression_buffer));
1.14 markus 384: }
385: /* Compute packet length without padding (add checksum, remove padding). */
386: len = buffer_len(&outgoing_packet) + 4 - 8;
387:
1.32 markus 388: /* Insert padding. Initialized to zero in packet_start1() */
1.14 markus 389: padding = 8 - len % 8;
1.62 markus 390: if (send_context.cipher->number != SSH_CIPHER_NONE) {
1.14 markus 391: cp = buffer_ptr(&outgoing_packet);
392: for (i = 0; i < padding; i++) {
393: if (i % 4 == 0)
394: rand = arc4random();
395: cp[7 - i] = rand & 0xff;
396: rand >>= 8;
397: }
398: }
399: buffer_consume(&outgoing_packet, 8 - padding);
400:
401: /* Add check bytes. */
1.40 markus 402: checksum = ssh_crc32((u_char *) buffer_ptr(&outgoing_packet),
1.34 deraadt 403: buffer_len(&outgoing_packet));
1.14 markus 404: PUT_32BIT(buf, checksum);
405: buffer_append(&outgoing_packet, buf, 4);
1.1 deraadt 406:
407: #ifdef PACKET_DEBUG
1.14 markus 408: fprintf(stderr, "packet_send plain: ");
409: buffer_dump(&outgoing_packet);
1.1 deraadt 410: #endif
411:
1.14 markus 412: /* Append to output. */
413: PUT_32BIT(buf, len);
414: buffer_append(&output, buf, 4);
1.76 stevesk 415: cp = buffer_append_space(&output, buffer_len(&outgoing_packet));
1.62 markus 416: cipher_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet),
1.75 deraadt 417: buffer_len(&outgoing_packet));
1.14 markus 418:
1.1 deraadt 419: #ifdef PACKET_DEBUG
1.14 markus 420: fprintf(stderr, "encrypted: ");
421: buffer_dump(&output);
1.1 deraadt 422: #endif
423:
1.14 markus 424: buffer_clear(&outgoing_packet);
1.1 deraadt 425:
1.16 markus 426: /*
427: * Note that the packet is now only buffered in output. It won\'t be
428: * actually sent until packet_write_wait or packet_write_poll is
429: * called.
430: */
1.1 deraadt 431: }
432:
1.68 itojun 433: static void
1.57 markus 434: set_newkeys(int mode)
435: {
436: Enc *enc;
437: Mac *mac;
438: Comp *comp;
439: CipherContext *cc;
440:
441: debug("newkeys: mode %d", mode);
442:
443: cc = (mode == MODE_OUT) ? &send_context : &receive_context;
444: if (newkeys[mode] != NULL) {
445: debug("newkeys: rekeying");
1.59 markus 446: /* todo: free old keys, reset compression/cipher-ctxt; */
1.57 markus 447: memset(cc, 0, sizeof(*cc));
1.59 markus 448: enc = &newkeys[mode]->enc;
449: mac = &newkeys[mode]->mac;
450: comp = &newkeys[mode]->comp;
1.61 markus 451: memset(mac->key, 0, mac->key_len);
1.59 markus 452: xfree(enc->name);
453: xfree(enc->iv);
454: xfree(enc->key);
455: xfree(mac->name);
456: xfree(mac->key);
457: xfree(comp->name);
1.58 markus 458: xfree(newkeys[mode]);
1.57 markus 459: }
460: newkeys[mode] = kex_get_newkeys(mode);
461: if (newkeys[mode] == NULL)
462: fatal("newkeys: no keys for mode %d", mode);
463: enc = &newkeys[mode]->enc;
464: mac = &newkeys[mode]->mac;
465: comp = &newkeys[mode]->comp;
466: if (mac->md != NULL)
467: mac->enabled = 1;
468: DBG(debug("cipher_init_context: %d", mode));
469: cipher_init(cc, enc->cipher, enc->key, enc->cipher->key_len,
470: enc->iv, enc->cipher->block_size);
1.59 markus 471: memset(enc->iv, 0, enc->cipher->block_size);
472: memset(enc->key, 0, enc->cipher->key_len);
1.57 markus 473: if (comp->type != 0 && comp->enabled == 0) {
1.60 markus 474: packet_init_compression();
475: if (mode == MODE_OUT)
476: buffer_compress_init_send(6);
477: else
478: buffer_compress_init_recv();
1.57 markus 479: comp->enabled = 1;
480: }
481: }
482:
1.16 markus 483: /*
1.25 markus 484: * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue)
485: */
1.68 itojun 486: static void
1.49 itojun 487: packet_send2(void)
1.25 markus 488: {
1.50 markus 489: static u_int32_t seqnr = 0;
1.62 markus 490: u_char type, *ucp, *macbuf = NULL;
1.71 markus 491: u_char padlen, pad;
1.25 markus 492: char *cp;
1.40 markus 493: u_int packet_length = 0;
1.71 markus 494: u_int i, len;
1.25 markus 495: u_int32_t rand = 0;
496: Enc *enc = NULL;
497: Mac *mac = NULL;
498: Comp *comp = NULL;
499: int block_size;
500:
1.57 markus 501: if (newkeys[MODE_OUT] != NULL) {
502: enc = &newkeys[MODE_OUT]->enc;
503: mac = &newkeys[MODE_OUT]->mac;
504: comp = &newkeys[MODE_OUT]->comp;
1.25 markus 505: }
1.37 markus 506: block_size = enc ? enc->cipher->block_size : 8;
1.25 markus 507:
1.62 markus 508: ucp = (u_char *) buffer_ptr(&outgoing_packet);
509: type = ucp[5];
1.25 markus 510:
511: #ifdef PACKET_DEBUG
512: fprintf(stderr, "plain: ");
513: buffer_dump(&outgoing_packet);
514: #endif
515:
516: if (comp && comp->enabled) {
517: len = buffer_len(&outgoing_packet);
518: /* skip header, compress only payload */
519: buffer_consume(&outgoing_packet, 5);
520: buffer_clear(&compression_buffer);
521: buffer_compress(&outgoing_packet, &compression_buffer);
522: buffer_clear(&outgoing_packet);
523: buffer_append(&outgoing_packet, "\0\0\0\0\0", 5);
524: buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer),
525: buffer_len(&compression_buffer));
526: DBG(debug("compression: raw %d compressed %d", len,
527: buffer_len(&outgoing_packet)));
528: }
529:
530: /* sizeof (packet_len + pad_len + payload) */
531: len = buffer_len(&outgoing_packet);
532:
533: /*
534: * calc size of padding, alloc space, get random data,
535: * minimum padding is 4 bytes
536: */
537: padlen = block_size - (len % block_size);
538: if (padlen < 4)
539: padlen += block_size;
1.71 markus 540: if (extra_pad) {
541: /* will wrap if extra_pad+padlen > 255 */
542: extra_pad = roundup(extra_pad, block_size);
543: pad = extra_pad - ((len + padlen) % extra_pad);
544: debug("packet_send2: adding %d (len %d padlen %d extra_pad %d)",
545: pad, len, padlen, extra_pad);
546: padlen += pad;
547: extra_pad = 0;
548: }
1.76 stevesk 549: cp = buffer_append_space(&outgoing_packet, padlen);
1.38 markus 550: if (enc && enc->cipher->number != SSH_CIPHER_NONE) {
1.32 markus 551: /* random padding */
1.25 markus 552: for (i = 0; i < padlen; i++) {
553: if (i % 4 == 0)
554: rand = arc4random();
555: cp[i] = rand & 0xff;
1.52 markus 556: rand >>= 8;
1.25 markus 557: }
1.32 markus 558: } else {
559: /* clear padding */
560: memset(cp, 0, padlen);
1.25 markus 561: }
562: /* packet_length includes payload, padding and padding length field */
563: packet_length = buffer_len(&outgoing_packet) - 4;
1.62 markus 564: ucp = (u_char *)buffer_ptr(&outgoing_packet);
565: PUT_32BIT(ucp, packet_length);
566: ucp[4] = padlen;
1.25 markus 567: DBG(debug("send: len %d (includes padlen %d)", packet_length+4, padlen));
568:
569: /* compute MAC over seqnr and packet(length fields, payload, padding) */
570: if (mac && mac->enabled) {
1.50 markus 571: macbuf = mac_compute(mac, seqnr,
1.40 markus 572: (u_char *) buffer_ptr(&outgoing_packet),
1.50 markus 573: buffer_len(&outgoing_packet));
1.36 markus 574: DBG(debug("done calc MAC out #%d", seqnr));
1.25 markus 575: }
576: /* encrypt packet and append to output buffer. */
1.76 stevesk 577: cp = buffer_append_space(&output, buffer_len(&outgoing_packet));
1.62 markus 578: cipher_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet),
1.25 markus 579: buffer_len(&outgoing_packet));
580: /* append unencrypted MAC */
581: if (mac && mac->enabled)
582: buffer_append(&output, (char *)macbuf, mac->mac_len);
583: #ifdef PACKET_DEBUG
584: fprintf(stderr, "encrypted: ");
585: buffer_dump(&output);
586: #endif
1.29 markus 587: /* increment sequence number for outgoing packets */
588: if (++seqnr == 0)
589: log("outgoing seqnr wraps around");
1.25 markus 590: buffer_clear(&outgoing_packet);
591:
1.57 markus 592: if (type == SSH2_MSG_NEWKEYS)
593: set_newkeys(MODE_OUT);
1.25 markus 594: }
595:
596: void
1.73 itojun 597: packet_send(void)
1.25 markus 598: {
1.62 markus 599: if (compat20)
1.25 markus 600: packet_send2();
601: else
602: packet_send1();
603: DBG(debug("packet_send done"));
604: }
605:
606: /*
1.16 markus 607: * Waits until a packet has been received, and returns its type. Note that
608: * no other data is processed until this returns, so this function should not
609: * be used during the interactive session.
610: */
1.1 deraadt 611:
1.2 provos 612: int
1.77 djm 613: packet_read_seqnr(int *payload_len_ptr, u_int32_t *seqnr_p)
1.1 deraadt 614: {
1.14 markus 615: int type, len;
1.56 millert 616: fd_set *setp;
1.14 markus 617: char buf[8192];
1.25 markus 618: DBG(debug("packet_read()"));
1.14 markus 619:
1.56 millert 620: setp = (fd_set *)xmalloc(howmany(connection_in+1, NFDBITS) *
621: sizeof(fd_mask));
622:
1.14 markus 623: /* Since we are blocking, ensure that all written packets have been sent. */
624: packet_write_wait();
625:
626: /* Stay in the loop until we have received a complete packet. */
627: for (;;) {
628: /* Try to read a packet from the buffer. */
1.77 djm 629: type = packet_read_poll_seqnr(payload_len_ptr, seqnr_p);
1.62 markus 630: if (!compat20 && (
1.32 markus 631: type == SSH_SMSG_SUCCESS
1.14 markus 632: || type == SSH_SMSG_FAILURE
633: || type == SSH_CMSG_EOF
1.32 markus 634: || type == SSH_CMSG_EXIT_CONFIRMATION))
1.78 ! markus 635: packet_done();
1.14 markus 636: /* If we got a packet, return it. */
1.56 millert 637: if (type != SSH_MSG_NONE) {
638: xfree(setp);
1.14 markus 639: return type;
1.56 millert 640: }
1.16 markus 641: /*
642: * Otherwise, wait for some data to arrive, add it to the
643: * buffer, and try again.
644: */
1.56 millert 645: memset(setp, 0, howmany(connection_in + 1, NFDBITS) *
646: sizeof(fd_mask));
647: FD_SET(connection_in, setp);
1.16 markus 648:
1.14 markus 649: /* Wait for some data to arrive. */
1.56 millert 650: while (select(connection_in + 1, setp, NULL, NULL, NULL) == -1 &&
1.51 deraadt 651: (errno == EAGAIN || errno == EINTR))
652: ;
1.16 markus 653:
1.14 markus 654: /* Read data from the socket. */
655: len = read(connection_in, buf, sizeof(buf));
1.18 markus 656: if (len == 0) {
657: log("Connection closed by %.200s", get_remote_ipaddr());
658: fatal_cleanup();
659: }
1.14 markus 660: if (len < 0)
661: fatal("Read from socket failed: %.100s", strerror(errno));
662: /* Append it to the buffer. */
663: packet_process_incoming(buf, len);
664: }
665: /* NOTREACHED */
1.1 deraadt 666: }
667:
1.77 djm 668: int
669: packet_read(int *payload_len_ptr)
670: {
671: return packet_read_seqnr(payload_len_ptr, NULL);
672: }
673:
1.16 markus 674: /*
675: * Waits until a packet has been received, verifies that its type matches
676: * that given, and gives a fatal error and exits if there is a mismatch.
677: */
1.1 deraadt 678:
1.2 provos 679: void
680: packet_read_expect(int *payload_len_ptr, int expected_type)
1.1 deraadt 681: {
1.14 markus 682: int type;
1.1 deraadt 683:
1.14 markus 684: type = packet_read(payload_len_ptr);
685: if (type != expected_type)
686: packet_disconnect("Protocol error: expected packet type %d, got %d",
1.25 markus 687: expected_type, type);
1.1 deraadt 688: }
689:
690: /* Checks if a full packet is available in the data received so far via
1.14 markus 691: * packet_process_incoming. If so, reads the packet; otherwise returns
692: * SSH_MSG_NONE. This does not wait for data from the connection.
693: *
694: * SSH_MSG_DISCONNECT is handled specially here. Also,
695: * SSH_MSG_IGNORE messages are skipped by this function and are never returned
696: * to higher levels.
697: *
698: * The returned payload_len does include space consumed by:
699: * Packet length
700: * Padding
701: * Packet type
702: * Check bytes
703: */
1.1 deraadt 704:
1.68 itojun 705: static int
1.25 markus 706: packet_read_poll1(int *payload_len_ptr)
1.1 deraadt 707: {
1.40 markus 708: u_int len, padded_len;
1.62 markus 709: u_char *ucp, type;
710: char *cp;
1.40 markus 711: u_int checksum, stored_checksum;
1.14 markus 712:
713: /* Check if input size is less than minimum packet size. */
714: if (buffer_len(&input) < 4 + 8)
715: return SSH_MSG_NONE;
716: /* Get length of incoming packet. */
1.40 markus 717: ucp = (u_char *) buffer_ptr(&input);
1.14 markus 718: len = GET_32BIT(ucp);
719: if (len < 1 + 2 + 2 || len > 256 * 1024)
720: packet_disconnect("Bad packet length %d.", len);
721: padded_len = (len + 8) & ~7;
722:
723: /* Check if the packet has been entirely received. */
724: if (buffer_len(&input) < 4 + padded_len)
725: return SSH_MSG_NONE;
726:
727: /* The entire packet is in buffer. */
728:
729: /* Consume packet length. */
730: buffer_consume(&input, 4);
731:
1.62 markus 732: /*
733: * Cryptographic attack detector for ssh
734: * (C)1998 CORE-SDI, Buenos Aires Argentina
735: * Ariel Futoransky(futo@core-sdi.com)
736: */
737: if (receive_context.cipher->number != SSH_CIPHER_NONE &&
738: detect_attack(buffer_ptr(&input), padded_len, NULL) == DEATTACK_DETECTED)
739: packet_disconnect("crc32 compensation attack: network attack detected");
740:
741: /* Decrypt data to incoming_packet. */
1.14 markus 742: buffer_clear(&incoming_packet);
1.76 stevesk 743: cp = buffer_append_space(&incoming_packet, padded_len);
1.62 markus 744: cipher_decrypt(&receive_context, cp, buffer_ptr(&input), padded_len);
745:
1.14 markus 746: buffer_consume(&input, padded_len);
1.1 deraadt 747:
748: #ifdef PACKET_DEBUG
1.14 markus 749: fprintf(stderr, "read_poll plain: ");
750: buffer_dump(&incoming_packet);
1.1 deraadt 751: #endif
752:
1.14 markus 753: /* Compute packet checksum. */
1.40 markus 754: checksum = ssh_crc32((u_char *) buffer_ptr(&incoming_packet),
1.25 markus 755: buffer_len(&incoming_packet) - 4);
1.14 markus 756:
757: /* Skip padding. */
758: buffer_consume(&incoming_packet, 8 - len % 8);
759:
760: /* Test check bytes. */
761: if (len != buffer_len(&incoming_packet))
1.77 djm 762: packet_disconnect("packet_read_poll1: len %d != buffer_len %d.",
1.25 markus 763: len, buffer_len(&incoming_packet));
1.14 markus 764:
1.40 markus 765: ucp = (u_char *) buffer_ptr(&incoming_packet) + len - 4;
1.14 markus 766: stored_checksum = GET_32BIT(ucp);
767: if (checksum != stored_checksum)
768: packet_disconnect("Corrupted check bytes on input.");
769: buffer_consume_end(&incoming_packet, 4);
770:
771: if (packet_compression) {
772: buffer_clear(&compression_buffer);
773: buffer_uncompress(&incoming_packet, &compression_buffer);
774: buffer_clear(&incoming_packet);
775: buffer_append(&incoming_packet, buffer_ptr(&compression_buffer),
1.25 markus 776: buffer_len(&compression_buffer));
1.14 markus 777: }
1.62 markus 778: type = buffer_get_char(&incoming_packet);
1.14 markus 779: *payload_len_ptr = buffer_len(&incoming_packet);
1.62 markus 780: return type;
1.1 deraadt 781: }
1.14 markus 782:
1.68 itojun 783: static int
1.77 djm 784: packet_read_poll2(int *payload_len_ptr, u_int32_t *seqnr_p)
1.25 markus 785: {
1.50 markus 786: static u_int32_t seqnr = 0;
787: static u_int packet_length = 0;
1.40 markus 788: u_int padlen, need;
1.62 markus 789: u_char *macbuf, *ucp, type;
1.25 markus 790: char *cp;
791: int maclen, block_size;
792: Enc *enc = NULL;
793: Mac *mac = NULL;
794: Comp *comp = NULL;
795:
1.57 markus 796: if (newkeys[MODE_IN] != NULL) {
797: enc = &newkeys[MODE_IN]->enc;
798: mac = &newkeys[MODE_IN]->mac;
799: comp = &newkeys[MODE_IN]->comp;
1.25 markus 800: }
801: maclen = mac && mac->enabled ? mac->mac_len : 0;
1.37 markus 802: block_size = enc ? enc->cipher->block_size : 8;
1.25 markus 803:
804: if (packet_length == 0) {
805: /*
806: * check if input size is less than the cipher block size,
807: * decrypt first block and extract length of incoming packet
808: */
809: if (buffer_len(&input) < block_size)
810: return SSH_MSG_NONE;
811: buffer_clear(&incoming_packet);
1.76 stevesk 812: cp = buffer_append_space(&incoming_packet, block_size);
1.62 markus 813: cipher_decrypt(&receive_context, cp, buffer_ptr(&input),
1.25 markus 814: block_size);
1.40 markus 815: ucp = (u_char *) buffer_ptr(&incoming_packet);
1.25 markus 816: packet_length = GET_32BIT(ucp);
817: if (packet_length < 1 + 4 || packet_length > 256 * 1024) {
818: buffer_dump(&incoming_packet);
819: packet_disconnect("Bad packet length %d.", packet_length);
820: }
821: DBG(debug("input: packet len %d", packet_length+4));
822: buffer_consume(&input, block_size);
823: }
824: /* we have a partial packet of block_size bytes */
825: need = 4 + packet_length - block_size;
826: DBG(debug("partial packet %d, need %d, maclen %d", block_size,
827: need, maclen));
828: if (need % block_size != 0)
829: fatal("padding error: need %d block %d mod %d",
830: need, block_size, need % block_size);
831: /*
832: * check if the entire packet has been received and
833: * decrypt into incoming_packet
834: */
835: if (buffer_len(&input) < need + maclen)
836: return SSH_MSG_NONE;
837: #ifdef PACKET_DEBUG
838: fprintf(stderr, "read_poll enc/full: ");
839: buffer_dump(&input);
840: #endif
1.76 stevesk 841: cp = buffer_append_space(&incoming_packet, need);
1.62 markus 842: cipher_decrypt(&receive_context, cp, buffer_ptr(&input), need);
1.25 markus 843: buffer_consume(&input, need);
844: /*
845: * compute MAC over seqnr and packet,
846: * increment sequence number for incoming packet
847: */
1.29 markus 848: if (mac && mac->enabled) {
1.50 markus 849: macbuf = mac_compute(mac, seqnr,
1.40 markus 850: (u_char *) buffer_ptr(&incoming_packet),
1.50 markus 851: buffer_len(&incoming_packet));
1.25 markus 852: if (memcmp(macbuf, buffer_ptr(&input), mac->mac_len) != 0)
1.36 markus 853: packet_disconnect("Corrupted MAC on input.");
854: DBG(debug("MAC #%d ok", seqnr));
1.25 markus 855: buffer_consume(&input, mac->mac_len);
856: }
1.77 djm 857: if (seqnr_p != NULL)
858: *seqnr_p = seqnr;
1.29 markus 859: if (++seqnr == 0)
860: log("incoming seqnr wraps around");
1.25 markus 861:
862: /* get padlen */
1.76 stevesk 863: cp = buffer_ptr(&incoming_packet);
864: cp += 4;
1.62 markus 865: padlen = (u_char) *cp;
1.25 markus 866: DBG(debug("input: padlen %d", padlen));
867: if (padlen < 4)
868: packet_disconnect("Corrupted padlen %d on input.", padlen);
869:
870: /* skip packet size + padlen, discard padding */
871: buffer_consume(&incoming_packet, 4 + 1);
872: buffer_consume_end(&incoming_packet, padlen);
873:
874: DBG(debug("input: len before de-compress %d", buffer_len(&incoming_packet)));
875: if (comp && comp->enabled) {
876: buffer_clear(&compression_buffer);
877: buffer_uncompress(&incoming_packet, &compression_buffer);
878: buffer_clear(&incoming_packet);
879: buffer_append(&incoming_packet, buffer_ptr(&compression_buffer),
880: buffer_len(&compression_buffer));
881: DBG(debug("input: len after de-compress %d", buffer_len(&incoming_packet)));
882: }
883: /*
884: * get packet type, implies consume.
885: * return length of payload (without type field)
886: */
1.62 markus 887: type = buffer_get_char(&incoming_packet);
1.57 markus 888: if (type == SSH2_MSG_NEWKEYS)
889: set_newkeys(MODE_IN);
1.62 markus 890: *payload_len_ptr = buffer_len(&incoming_packet);
1.25 markus 891: #ifdef PACKET_DEBUG
1.55 deraadt 892: fprintf(stderr, "read/plain[%d]:\r\n", type);
1.25 markus 893: buffer_dump(&incoming_packet);
894: #endif
1.62 markus 895: /* reset for next packet */
896: packet_length = 0;
897: return type;
1.25 markus 898: }
899:
900: int
1.77 djm 901: packet_read_poll_seqnr(int *payload_len_ptr, u_int32_t *seqnr_p)
1.25 markus 902: {
1.62 markus 903: int reason;
904: u_char type;
1.25 markus 905: char *msg;
1.62 markus 906:
1.25 markus 907: for (;;) {
1.62 markus 908: if (compat20) {
1.77 djm 909: type = packet_read_poll2(payload_len_ptr, seqnr_p);
1.62 markus 910: if (type)
1.25 markus 911: DBG(debug("received packet type %d", type));
1.74 deraadt 912: switch (type) {
1.25 markus 913: case SSH2_MSG_IGNORE:
914: break;
915: case SSH2_MSG_DEBUG:
916: packet_get_char();
917: msg = packet_get_string(NULL);
918: debug("Remote: %.900s", msg);
919: xfree(msg);
920: msg = packet_get_string(NULL);
921: xfree(msg);
922: break;
923: case SSH2_MSG_DISCONNECT:
924: reason = packet_get_int();
925: msg = packet_get_string(NULL);
1.41 markus 926: log("Received disconnect from %s: %d: %.400s", get_remote_ipaddr(),
927: reason, msg);
1.25 markus 928: xfree(msg);
929: fatal_cleanup();
930: break;
931: default:
932: return type;
933: break;
1.48 stevesk 934: }
1.25 markus 935: } else {
1.62 markus 936: type = packet_read_poll1(payload_len_ptr);
1.74 deraadt 937: switch (type) {
1.25 markus 938: case SSH_MSG_IGNORE:
939: break;
940: case SSH_MSG_DEBUG:
941: msg = packet_get_string(NULL);
942: debug("Remote: %.900s", msg);
943: xfree(msg);
944: break;
945: case SSH_MSG_DISCONNECT:
946: msg = packet_get_string(NULL);
1.41 markus 947: log("Received disconnect from %s: %.400s", get_remote_ipaddr(),
948: msg);
1.25 markus 949: fatal_cleanup();
950: xfree(msg);
951: break;
952: default:
1.62 markus 953: if (type)
1.25 markus 954: DBG(debug("received packet type %d", type));
955: return type;
956: break;
1.48 stevesk 957: }
1.25 markus 958: }
959: }
1.77 djm 960: }
961:
962: int
963: packet_read_poll(int *payload_len_ptr)
964: {
965: return packet_read_poll_seqnr(payload_len_ptr, NULL);
1.25 markus 966: }
967:
1.16 markus 968: /*
969: * Buffers the given amount of input characters. This is intended to be used
970: * together with packet_read_poll.
971: */
1.1 deraadt 972:
1.2 provos 973: void
1.40 markus 974: packet_process_incoming(const char *buf, u_int len)
1.1 deraadt 975: {
1.14 markus 976: buffer_append(&input, buf, len);
1.1 deraadt 977: }
978:
979: /* Returns a character from the packet. */
980:
1.40 markus 981: u_int
1.73 itojun 982: packet_get_char(void)
1.1 deraadt 983: {
1.14 markus 984: char ch;
985: buffer_get(&incoming_packet, &ch, 1);
1.40 markus 986: return (u_char) ch;
1.1 deraadt 987: }
988:
989: /* Returns an integer from the packet data. */
990:
1.40 markus 991: u_int
1.73 itojun 992: packet_get_int(void)
1.1 deraadt 993: {
1.14 markus 994: return buffer_get_int(&incoming_packet);
1.1 deraadt 995: }
996:
1.16 markus 997: /*
998: * Returns an arbitrary precision integer from the packet data. The integer
999: * must have been initialized before this call.
1000: */
1.1 deraadt 1001:
1.2 provos 1002: void
1.14 markus 1003: packet_get_bignum(BIGNUM * value, int *length_ptr)
1.1 deraadt 1004: {
1.14 markus 1005: *length_ptr = buffer_get_bignum(&incoming_packet, value);
1.24 markus 1006: }
1007:
1008: void
1009: packet_get_bignum2(BIGNUM * value, int *length_ptr)
1010: {
1011: *length_ptr = buffer_get_bignum2(&incoming_packet, value);
1012: }
1013:
1.76 stevesk 1014: void *
1.24 markus 1015: packet_get_raw(int *length_ptr)
1016: {
1017: int bytes = buffer_len(&incoming_packet);
1018: if (length_ptr != NULL)
1019: *length_ptr = bytes;
1020: return buffer_ptr(&incoming_packet);
1.28 markus 1021: }
1022:
1023: int
1024: packet_remaining(void)
1025: {
1026: return buffer_len(&incoming_packet);
1.1 deraadt 1027: }
1028:
1.16 markus 1029: /*
1030: * Returns a string from the packet data. The string is allocated using
1031: * xmalloc; it is the responsibility of the calling program to free it when
1032: * no longer needed. The length_ptr argument may be NULL, or point to an
1033: * integer into which the length of the string is stored.
1034: */
1.1 deraadt 1035:
1.76 stevesk 1036: void *
1.40 markus 1037: packet_get_string(u_int *length_ptr)
1.1 deraadt 1038: {
1.14 markus 1039: return buffer_get_string(&incoming_packet, length_ptr);
1.1 deraadt 1040: }
1041:
1.16 markus 1042: /*
1043: * Sends a diagnostic message from the server to the client. This message
1044: * can be sent at any time (but not while constructing another message). The
1045: * message is printed immediately, but only if the client is being executed
1046: * in verbose mode. These messages are primarily intended to ease debugging
1047: * authentication problems. The length of the formatted message must not
1048: * exceed 1024 bytes. This will automatically call packet_write_wait.
1049: */
1.1 deraadt 1050:
1.2 provos 1051: void
1.14 markus 1052: packet_send_debug(const char *fmt,...)
1.1 deraadt 1053: {
1.14 markus 1054: char buf[1024];
1055: va_list args;
1.39 markus 1056:
1057: if (compat20 && (datafellows & SSH_BUG_DEBUG))
1058: return;
1.14 markus 1059:
1060: va_start(args, fmt);
1061: vsnprintf(buf, sizeof(buf), fmt, args);
1062: va_end(args);
1063:
1.30 markus 1064: if (compat20) {
1065: packet_start(SSH2_MSG_DEBUG);
1066: packet_put_char(0); /* bool: always display */
1067: packet_put_cstring(buf);
1068: packet_put_cstring("");
1069: } else {
1070: packet_start(SSH_MSG_DEBUG);
1071: packet_put_cstring(buf);
1072: }
1.14 markus 1073: packet_send();
1074: packet_write_wait();
1.1 deraadt 1075: }
1076:
1.16 markus 1077: /*
1078: * Logs the error plus constructs and sends a disconnect packet, closes the
1079: * connection, and exits. This function never returns. The error message
1080: * should not contain a newline. The length of the formatted message must
1081: * not exceed 1024 bytes.
1082: */
1.1 deraadt 1083:
1.2 provos 1084: void
1.14 markus 1085: packet_disconnect(const char *fmt,...)
1.1 deraadt 1086: {
1.14 markus 1087: char buf[1024];
1088: va_list args;
1089: static int disconnecting = 0;
1090: if (disconnecting) /* Guard against recursive invocations. */
1091: fatal("packet_disconnect called recursively.");
1092: disconnecting = 1;
1093:
1.16 markus 1094: /*
1095: * Format the message. Note that the caller must make sure the
1096: * message is of limited size.
1097: */
1.14 markus 1098: va_start(args, fmt);
1099: vsnprintf(buf, sizeof(buf), fmt, args);
1100: va_end(args);
1101:
1102: /* Send the disconnect message to the other side, and wait for it to get sent. */
1.25 markus 1103: if (compat20) {
1104: packet_start(SSH2_MSG_DISCONNECT);
1105: packet_put_int(SSH2_DISCONNECT_PROTOCOL_ERROR);
1106: packet_put_cstring(buf);
1107: packet_put_cstring("");
1108: } else {
1109: packet_start(SSH_MSG_DISCONNECT);
1.65 markus 1110: packet_put_cstring(buf);
1.25 markus 1111: }
1.14 markus 1112: packet_send();
1113: packet_write_wait();
1114:
1115: /* Stop listening for connections. */
1.67 markus 1116: channel_close_all();
1.14 markus 1117:
1118: /* Close the connection. */
1119: packet_close();
1.1 deraadt 1120:
1.14 markus 1121: /* Display the error locally and exit. */
1.17 markus 1122: log("Disconnecting: %.100s", buf);
1123: fatal_cleanup();
1.1 deraadt 1124: }
1125:
1.16 markus 1126: /* Checks if there is any buffered output, and tries to write some of the output. */
1.1 deraadt 1127:
1.2 provos 1128: void
1.73 itojun 1129: packet_write_poll(void)
1.1 deraadt 1130: {
1.14 markus 1131: int len = buffer_len(&output);
1132: if (len > 0) {
1133: len = write(connection_out, buffer_ptr(&output), len);
1134: if (len <= 0) {
1135: if (errno == EAGAIN)
1136: return;
1137: else
1138: fatal("Write failed: %.100s", strerror(errno));
1139: }
1140: buffer_consume(&output, len);
1141: }
1.1 deraadt 1142: }
1143:
1.16 markus 1144: /*
1145: * Calls packet_write_poll repeatedly until all pending output data has been
1146: * written.
1147: */
1.1 deraadt 1148:
1.2 provos 1149: void
1.73 itojun 1150: packet_write_wait(void)
1.1 deraadt 1151: {
1.56 millert 1152: fd_set *setp;
1153:
1154: setp = (fd_set *)xmalloc(howmany(connection_out + 1, NFDBITS) *
1155: sizeof(fd_mask));
1.14 markus 1156: packet_write_poll();
1157: while (packet_have_data_to_write()) {
1.56 millert 1158: memset(setp, 0, howmany(connection_out + 1, NFDBITS) *
1159: sizeof(fd_mask));
1160: FD_SET(connection_out, setp);
1161: while (select(connection_out + 1, NULL, setp, NULL, NULL) == -1 &&
1.51 deraadt 1162: (errno == EAGAIN || errno == EINTR))
1163: ;
1.14 markus 1164: packet_write_poll();
1165: }
1.56 millert 1166: xfree(setp);
1.1 deraadt 1167: }
1168:
1169: /* Returns true if there is buffered data to write to the connection. */
1170:
1.2 provos 1171: int
1.73 itojun 1172: packet_have_data_to_write(void)
1.1 deraadt 1173: {
1.14 markus 1174: return buffer_len(&output) != 0;
1.1 deraadt 1175: }
1176:
1177: /* Returns true if there is not too much data to write to the connection. */
1178:
1.2 provos 1179: int
1.73 itojun 1180: packet_not_very_much_data_to_write(void)
1.1 deraadt 1181: {
1.14 markus 1182: if (interactive_mode)
1183: return buffer_len(&output) < 16384;
1184: else
1185: return buffer_len(&output) < 128 * 1024;
1.1 deraadt 1186: }
1187:
1188: /* Informs that the current session is interactive. Sets IP flags for that. */
1189:
1.2 provos 1190: void
1.43 markus 1191: packet_set_interactive(int interactive)
1.1 deraadt 1192: {
1.43 markus 1193: static int called = 0;
1.44 markus 1194: int lowdelay = IPTOS_LOWDELAY;
1195: int throughput = IPTOS_THROUGHPUT;
1196: int on = 1;
1197:
1.43 markus 1198: if (called)
1199: return;
1200: called = 1;
1.1 deraadt 1201:
1.14 markus 1202: /* Record that we are in interactive mode. */
1203: interactive_mode = interactive;
1.1 deraadt 1204:
1.19 markus 1205: /* Only set socket options if using a socket. */
1206: if (!packet_connection_is_on_socket())
1.14 markus 1207: return;
1.19 markus 1208: /*
1.42 markus 1209: * IPTOS_LOWDELAY and IPTOS_THROUGHPUT are IPv4 only
1.19 markus 1210: */
1.14 markus 1211: if (interactive) {
1.16 markus 1212: /*
1213: * Set IP options for an interactive connection. Use
1214: * IPTOS_LOWDELAY and TCP_NODELAY.
1215: */
1.42 markus 1216: if (packet_connection_is_ipv4()) {
1217: if (setsockopt(connection_in, IPPROTO_IP, IP_TOS,
1218: (void *) &lowdelay, sizeof(lowdelay)) < 0)
1219: error("setsockopt IPTOS_LOWDELAY: %.100s",
1220: strerror(errno));
1221: }
1.14 markus 1222: if (setsockopt(connection_in, IPPROTO_TCP, TCP_NODELAY, (void *) &on,
1.19 markus 1223: sizeof(on)) < 0)
1.14 markus 1224: error("setsockopt TCP_NODELAY: %.100s", strerror(errno));
1.42 markus 1225: } else if (packet_connection_is_ipv4()) {
1.16 markus 1226: /*
1227: * Set IP options for a non-interactive connection. Use
1228: * IPTOS_THROUGHPUT.
1229: */
1.14 markus 1230: if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, (void *) &throughput,
1.19 markus 1231: sizeof(throughput)) < 0)
1.14 markus 1232: error("setsockopt IPTOS_THROUGHPUT: %.100s", strerror(errno));
1233: }
1.1 deraadt 1234: }
1235:
1236: /* Returns true if the current connection is interactive. */
1237:
1.2 provos 1238: int
1.73 itojun 1239: packet_is_interactive(void)
1.1 deraadt 1240: {
1.14 markus 1241: return interactive_mode;
1.12 markus 1242: }
1243:
1244: int
1245: packet_set_maxsize(int s)
1246: {
1.14 markus 1247: static int called = 0;
1248: if (called) {
1.25 markus 1249: log("packet_set_maxsize: called twice: old %d new %d",
1250: max_packet_size, s);
1.14 markus 1251: return -1;
1252: }
1253: if (s < 4 * 1024 || s > 1024 * 1024) {
1254: log("packet_set_maxsize: bad size %d", s);
1255: return -1;
1256: }
1.70 markus 1257: called = 1;
1.66 markus 1258: debug("packet_set_maxsize: setting to %d", s);
1.14 markus 1259: max_packet_size = s;
1260: return s;
1.53 markus 1261: }
1262:
1.71 markus 1263: /* roundup current message to pad bytes */
1264: void
1265: packet_add_padding(u_char pad)
1266: {
1267: extra_pad = pad;
1268: }
1269:
1.53 markus 1270: /*
1271: * 9.2. Ignored Data Message
1.61 markus 1272: *
1.53 markus 1273: * byte SSH_MSG_IGNORE
1274: * string data
1.61 markus 1275: *
1.53 markus 1276: * All implementations MUST understand (and ignore) this message at any
1277: * time (after receiving the protocol version). No implementation is
1278: * required to send them. This message can be used as an additional
1279: * protection measure against advanced traffic analysis techniques.
1280: */
1.54 markus 1281: void
1282: packet_send_ignore(int nbytes)
1283: {
1284: u_int32_t rand = 0;
1285: int i;
1286:
1287: packet_start(compat20 ? SSH2_MSG_IGNORE : SSH_MSG_IGNORE);
1.53 markus 1288: packet_put_int(nbytes);
1.75 deraadt 1289: for (i = 0; i < nbytes; i++) {
1.53 markus 1290: if (i % 4 == 0)
1291: rand = arc4random();
1292: packet_put_char(rand & 0xff);
1293: rand >>= 8;
1294: }
1.1 deraadt 1295: }
![[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