Annotation of src/usr.bin/ssh/packet.c, Revision 1.135
1.135 ! stevesk 1: /* $OpenBSD: packet.c,v 1.134 2006/07/10 16:37:36 stevesk Exp $ */
1.1 deraadt 2: /*
1.15 deraadt 3: * Author: Tatu Ylonen <ylo@cs.hut.fi>
4: * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5: * All rights reserved
1.35 deraadt 6: * This file contains code implementing the packet protocol and communication
7: * with the other side. This same code is used both on client and server side.
1.29 markus 8: *
1.35 deraadt 9: * As far as I am concerned, the code I have written for this software
10: * can be used freely for any purpose. Any derived versions of this
11: * software must be clearly marked as such, and if the derived work is
12: * incompatible with the protocol description in the RFC file, it must be
13: * called by a name other than "ssh" or "Secure Shell".
1.29 markus 14: *
1.25 markus 15: *
16: * SSH2 packet format added by Markus Friedl.
1.69 markus 17: * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
1.25 markus 18: *
1.35 deraadt 19: * Redistribution and use in source and binary forms, with or without
20: * modification, are permitted provided that the following conditions
21: * are met:
22: * 1. Redistributions of source code must retain the above copyright
23: * notice, this list of conditions and the following disclaimer.
24: * 2. Redistributions in binary form must reproduce the above copyright
25: * notice, this list of conditions and the following disclaimer in the
26: * documentation and/or other materials provided with the distribution.
27: *
28: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
29: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
30: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
31: * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
32: * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
33: * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
34: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
35: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
36: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
37: * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1.15 deraadt 38: */
1.1 deraadt 39:
40: #include "includes.h"
1.105 markus 41:
42: #include <sys/queue.h>
1.133 stevesk 43: #include <sys/types.h>
1.132 stevesk 44: #include <sys/socket.h>
1.121 stevesk 45:
46: #include <netinet/in_systm.h>
1.132 stevesk 47: #include <netinet/in.h>
1.121 stevesk 48: #include <netinet/ip.h>
1.134 stevesk 49:
1.135 ! stevesk 50: #include <errno.h>
1.134 stevesk 51: #include <stdarg.h>
1.1 deraadt 52:
53: #include "xmalloc.h"
54: #include "buffer.h"
55: #include "packet.h"
56: #include "bufaux.h"
57: #include "crc32.h"
58:
59: #include "compress.h"
1.9 dugsong 60: #include "deattack.h"
1.64 markus 61: #include "channels.h"
1.1 deraadt 62:
1.25 markus 63: #include "compat.h"
1.45 markus 64: #include "ssh1.h"
1.25 markus 65: #include "ssh2.h"
66:
1.37 markus 67: #include "cipher.h"
1.25 markus 68: #include "kex.h"
1.50 markus 69: #include "mac.h"
1.46 markus 70: #include "log.h"
71: #include "canohost.h"
1.87 stevesk 72: #include "misc.h"
1.95 markus 73: #include "ssh.h"
1.25 markus 74:
75: #ifdef PACKET_DEBUG
76: #define DBG(x) x
77: #else
78: #define DBG(x)
79: #endif
80:
1.16 markus 81: /*
82: * This variable contains the file descriptors used for communicating with
83: * the other side. connection_in is used for reading; connection_out for
84: * writing. These can be the same descriptor, in which case it is assumed to
85: * be a socket.
86: */
1.1 deraadt 87: static int connection_in = -1;
88: static int connection_out = -1;
89:
90: /* Protocol flags for the remote side. */
1.40 markus 91: static u_int remote_protocol_flags = 0;
1.1 deraadt 92:
93: /* Encryption context for receiving data. This is only used for decryption. */
94: static CipherContext receive_context;
1.14 markus 95:
96: /* Encryption context for sending data. This is only used for encryption. */
1.1 deraadt 97: static CipherContext send_context;
98:
99: /* Buffer for raw input data from the socket. */
1.91 markus 100: Buffer input;
1.1 deraadt 101:
102: /* Buffer for raw output data going to the socket. */
1.91 markus 103: Buffer output;
1.1 deraadt 104:
105: /* Buffer for the partial outgoing packet being constructed. */
106: static Buffer outgoing_packet;
107:
108: /* Buffer for the incoming packet currently being processed. */
109: static Buffer incoming_packet;
110:
111: /* Scratch buffer for packet compression/decompression. */
112: static Buffer compression_buffer;
1.60 markus 113: static int compression_buffer_ready = 0;
1.1 deraadt 114:
115: /* Flag indicating whether packet compression/decompression is enabled. */
116: static int packet_compression = 0;
117:
1.12 markus 118: /* default maximum packet size */
1.108 markus 119: u_int max_packet_size = 32768;
1.12 markus 120:
1.1 deraadt 121: /* Flag indicating whether this module has been initialized. */
122: static int initialized = 0;
123:
124: /* Set to true if the connection is interactive. */
125: static int interactive_mode = 0;
126:
1.118 markus 127: /* Set to true if we are the server side. */
128: static int server_side = 0;
129:
130: /* Set to true if we are authenticated. */
131: static int after_authentication = 0;
132:
1.25 markus 133: /* Session key information for Encryption and MAC */
1.57 markus 134: Newkeys *newkeys[MODE_MAX];
1.105 markus 135: static struct packet_state {
136: u_int32_t seqnr;
137: u_int32_t packets;
138: u_int64_t blocks;
139: } p_read, p_send;
140:
141: static u_int64_t max_blocks_in, max_blocks_out;
142: static u_int32_t rekey_limit;
1.25 markus 143:
1.95 markus 144: /* Session key for protocol v1 */
145: static u_char ssh1_key[SSH_SESSION_KEY_LENGTH];
146: static u_int ssh1_keylen;
147:
1.71 markus 148: /* roundup current message to extra_pad bytes */
149: static u_char extra_pad = 0;
150:
1.105 markus 151: struct packet {
152: TAILQ_ENTRY(packet) next;
153: u_char type;
154: Buffer payload;
155: };
156: TAILQ_HEAD(, packet) outgoing;
157:
1.16 markus 158: /*
159: * Sets the descriptors used for communication. Disables encryption until
160: * packet_set_encryption_key is called.
161: */
1.2 provos 162: void
163: packet_set_connection(int fd_in, int fd_out)
1.1 deraadt 164: {
1.37 markus 165: Cipher *none = cipher_by_name("none");
1.97 deraadt 166:
1.37 markus 167: if (none == NULL)
168: fatal("packet_set_connection: cannot load cipher 'none'");
1.14 markus 169: connection_in = fd_in;
170: connection_out = fd_out;
1.113 deraadt 171: cipher_init(&send_context, none, (const u_char *)"",
172: 0, NULL, 0, CIPHER_ENCRYPT);
173: cipher_init(&receive_context, none, (const u_char *)"",
174: 0, NULL, 0, CIPHER_DECRYPT);
1.62 markus 175: newkeys[MODE_IN] = newkeys[MODE_OUT] = NULL;
1.14 markus 176: if (!initialized) {
177: initialized = 1;
178: buffer_init(&input);
179: buffer_init(&output);
180: buffer_init(&outgoing_packet);
181: buffer_init(&incoming_packet);
1.105 markus 182: TAILQ_INIT(&outgoing);
1.14 markus 183: }
1.1 deraadt 184: }
185:
1.19 markus 186: /* Returns 1 if remote host is connected via socket, 0 if not. */
187:
188: int
1.73 itojun 189: packet_connection_is_on_socket(void)
1.19 markus 190: {
191: struct sockaddr_storage from, to;
192: socklen_t fromlen, tolen;
193:
194: /* filedescriptors in and out are the same, so it's a socket */
195: if (connection_in == connection_out)
196: return 1;
197: fromlen = sizeof(from);
198: memset(&from, 0, sizeof(from));
1.20 markus 199: if (getpeername(connection_in, (struct sockaddr *)&from, &fromlen) < 0)
1.19 markus 200: return 0;
201: tolen = sizeof(to);
202: memset(&to, 0, sizeof(to));
1.20 markus 203: if (getpeername(connection_out, (struct sockaddr *)&to, &tolen) < 0)
1.19 markus 204: return 0;
205: if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0)
206: return 0;
207: if (from.ss_family != AF_INET && from.ss_family != AF_INET6)
208: return 0;
209: return 1;
210: }
211:
1.92 markus 212: /*
1.91 markus 213: * Exports an IV from the CipherContext required to export the key
214: * state back from the unprivileged child to the privileged parent
215: * process.
216: */
217:
218: void
219: packet_get_keyiv(int mode, u_char *iv, u_int len)
220: {
221: CipherContext *cc;
222:
223: if (mode == MODE_OUT)
224: cc = &send_context;
225: else
226: cc = &receive_context;
227:
228: cipher_get_keyiv(cc, iv, len);
229: }
230:
231: int
232: packet_get_keycontext(int mode, u_char *dat)
233: {
234: CipherContext *cc;
1.92 markus 235:
1.91 markus 236: if (mode == MODE_OUT)
237: cc = &send_context;
238: else
239: cc = &receive_context;
240:
241: return (cipher_get_keycontext(cc, dat));
242: }
243:
244: void
245: packet_set_keycontext(int mode, u_char *dat)
246: {
247: CipherContext *cc;
1.92 markus 248:
1.91 markus 249: if (mode == MODE_OUT)
250: cc = &send_context;
251: else
252: cc = &receive_context;
253:
254: cipher_set_keycontext(cc, dat);
255: }
256:
257: int
258: packet_get_keyiv_len(int mode)
259: {
260: CipherContext *cc;
261:
262: if (mode == MODE_OUT)
263: cc = &send_context;
264: else
265: cc = &receive_context;
266:
267: return (cipher_get_keyiv_len(cc));
268: }
1.125 deraadt 269:
1.91 markus 270: void
271: packet_set_iv(int mode, u_char *dat)
272: {
273: CipherContext *cc;
274:
275: if (mode == MODE_OUT)
276: cc = &send_context;
277: else
278: cc = &receive_context;
279:
280: cipher_set_keyiv(cc, dat);
281: }
1.125 deraadt 282:
1.91 markus 283: int
1.107 deraadt 284: packet_get_ssh1_cipher(void)
1.91 markus 285: {
286: return (cipher_get_number(receive_context.cipher));
287: }
288:
1.105 markus 289: void
290: packet_get_state(int mode, u_int32_t *seqnr, u_int64_t *blocks, u_int32_t *packets)
291: {
292: struct packet_state *state;
1.104 markus 293:
1.105 markus 294: state = (mode == MODE_IN) ? &p_read : &p_send;
295: *seqnr = state->seqnr;
296: *blocks = state->blocks;
297: *packets = state->packets;
1.91 markus 298: }
299:
300: void
1.105 markus 301: packet_set_state(int mode, u_int32_t seqnr, u_int64_t blocks, u_int32_t packets)
1.91 markus 302: {
1.105 markus 303: struct packet_state *state;
304:
305: state = (mode == MODE_IN) ? &p_read : &p_send;
306: state->seqnr = seqnr;
307: state->blocks = blocks;
308: state->packets = packets;
1.91 markus 309: }
310:
1.19 markus 311: /* returns 1 if connection is via ipv4 */
312:
313: int
1.73 itojun 314: packet_connection_is_ipv4(void)
1.19 markus 315: {
316: struct sockaddr_storage to;
1.21 deraadt 317: socklen_t tolen = sizeof(to);
1.19 markus 318:
319: memset(&to, 0, sizeof(to));
320: if (getsockname(connection_out, (struct sockaddr *)&to, &tolen) < 0)
321: return 0;
322: if (to.ss_family != AF_INET)
323: return 0;
324: return 1;
325: }
326:
1.1 deraadt 327: /* Sets the connection into non-blocking mode. */
328:
1.2 provos 329: void
1.73 itojun 330: packet_set_nonblocking(void)
1.1 deraadt 331: {
1.14 markus 332: /* Set the socket into non-blocking mode. */
1.114 djm 333: set_nonblock(connection_in);
1.14 markus 334:
1.114 djm 335: if (connection_out != connection_in)
336: set_nonblock(connection_out);
1.1 deraadt 337: }
338:
339: /* Returns the socket used for reading. */
340:
1.2 provos 341: int
1.73 itojun 342: packet_get_connection_in(void)
1.1 deraadt 343: {
1.14 markus 344: return connection_in;
1.1 deraadt 345: }
346:
347: /* Returns the descriptor used for writing. */
348:
1.2 provos 349: int
1.73 itojun 350: packet_get_connection_out(void)
1.1 deraadt 351: {
1.14 markus 352: return connection_out;
1.1 deraadt 353: }
354:
355: /* Closes the connection and clears and frees internal data structures. */
356:
1.2 provos 357: void
1.73 itojun 358: packet_close(void)
1.1 deraadt 359: {
1.14 markus 360: if (!initialized)
361: return;
362: initialized = 0;
363: if (connection_in == connection_out) {
364: shutdown(connection_out, SHUT_RDWR);
365: close(connection_out);
366: } else {
367: close(connection_in);
368: close(connection_out);
369: }
370: buffer_free(&input);
371: buffer_free(&output);
372: buffer_free(&outgoing_packet);
373: buffer_free(&incoming_packet);
1.60 markus 374: if (compression_buffer_ready) {
1.14 markus 375: buffer_free(&compression_buffer);
376: buffer_compress_uninit();
377: }
1.88 markus 378: cipher_cleanup(&send_context);
379: cipher_cleanup(&receive_context);
1.1 deraadt 380: }
381:
382: /* Sets remote side protocol flags. */
383:
1.2 provos 384: void
1.40 markus 385: packet_set_protocol_flags(u_int protocol_flags)
1.1 deraadt 386: {
1.14 markus 387: remote_protocol_flags = protocol_flags;
1.1 deraadt 388: }
389:
390: /* Returns the remote protocol flags set earlier by the above function. */
391:
1.40 markus 392: u_int
1.73 itojun 393: packet_get_protocol_flags(void)
1.1 deraadt 394: {
1.14 markus 395: return remote_protocol_flags;
1.1 deraadt 396: }
397:
1.16 markus 398: /*
399: * Starts packet compression from the next packet on in both directions.
400: * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip.
401: */
1.1 deraadt 402:
1.68 itojun 403: static void
404: packet_init_compression(void)
1.60 markus 405: {
406: if (compression_buffer_ready == 1)
407: return;
408: compression_buffer_ready = 1;
409: buffer_init(&compression_buffer);
410: }
411:
1.2 provos 412: void
413: packet_start_compression(int level)
1.1 deraadt 414: {
1.62 markus 415: if (packet_compression && !compat20)
1.14 markus 416: fatal("Compression already enabled.");
417: packet_compression = 1;
1.60 markus 418: packet_init_compression();
419: buffer_compress_init_send(level);
420: buffer_compress_init_recv();
1.1 deraadt 421: }
422:
1.16 markus 423: /*
424: * Causes any further packets to be encrypted using the given key. The same
425: * key is used for both sending and reception. However, both directions are
426: * encrypted independently of each other.
427: */
1.95 markus 428:
1.2 provos 429: void
1.40 markus 430: packet_set_encryption_key(const u_char *key, u_int keylen,
1.37 markus 431: int number)
1.1 deraadt 432: {
1.37 markus 433: Cipher *cipher = cipher_by_number(number);
1.97 deraadt 434:
1.37 markus 435: if (cipher == NULL)
436: fatal("packet_set_encryption_key: unknown cipher number %d", number);
1.25 markus 437: if (keylen < 20)
1.37 markus 438: fatal("packet_set_encryption_key: keylen too small: %d", keylen);
1.95 markus 439: if (keylen > SSH_SESSION_KEY_LENGTH)
440: fatal("packet_set_encryption_key: keylen too big: %d", keylen);
441: memcpy(ssh1_key, key, keylen);
442: ssh1_keylen = keylen;
1.88 markus 443: cipher_init(&send_context, cipher, key, keylen, NULL, 0, CIPHER_ENCRYPT);
444: cipher_init(&receive_context, cipher, key, keylen, NULL, 0, CIPHER_DECRYPT);
1.95 markus 445: }
446:
447: u_int
448: packet_get_encryption_key(u_char *key)
449: {
450: if (key == NULL)
451: return (ssh1_keylen);
452: memcpy(key, ssh1_key, ssh1_keylen);
453: return (ssh1_keylen);
1.1 deraadt 454: }
455:
1.62 markus 456: /* Start constructing a packet to send. */
1.2 provos 457: void
1.62 markus 458: packet_start(u_char type)
1.1 deraadt 459: {
1.62 markus 460: u_char buf[9];
461: int len;
1.1 deraadt 462:
1.62 markus 463: DBG(debug("packet_start[%d]", type));
464: len = compat20 ? 6 : 9;
465: memset(buf, 0, len - 1);
466: buf[len - 1] = type;
1.14 markus 467: buffer_clear(&outgoing_packet);
1.62 markus 468: buffer_append(&outgoing_packet, buf, len);
1.25 markus 469: }
470:
1.62 markus 471: /* Append payload. */
1.2 provos 472: void
473: packet_put_char(int value)
1.1 deraadt 474: {
1.14 markus 475: char ch = value;
1.97 deraadt 476:
1.14 markus 477: buffer_append(&outgoing_packet, &ch, 1);
1.1 deraadt 478: }
1.125 deraadt 479:
1.2 provos 480: void
1.40 markus 481: packet_put_int(u_int value)
1.1 deraadt 482: {
1.14 markus 483: buffer_put_int(&outgoing_packet, value);
1.1 deraadt 484: }
1.125 deraadt 485:
1.2 provos 486: void
1.76 stevesk 487: packet_put_string(const void *buf, u_int len)
1.1 deraadt 488: {
1.14 markus 489: buffer_put_string(&outgoing_packet, buf, len);
1.1 deraadt 490: }
1.125 deraadt 491:
1.24 markus 492: void
493: packet_put_cstring(const char *str)
494: {
1.65 markus 495: buffer_put_cstring(&outgoing_packet, str);
1.24 markus 496: }
1.125 deraadt 497:
1.24 markus 498: void
1.76 stevesk 499: packet_put_raw(const void *buf, u_int len)
1.24 markus 500: {
501: buffer_append(&outgoing_packet, buf, len);
502: }
1.125 deraadt 503:
1.2 provos 504: void
1.14 markus 505: packet_put_bignum(BIGNUM * value)
1.1 deraadt 506: {
1.14 markus 507: buffer_put_bignum(&outgoing_packet, value);
1.1 deraadt 508: }
1.125 deraadt 509:
1.24 markus 510: void
511: packet_put_bignum2(BIGNUM * value)
512: {
513: buffer_put_bignum2(&outgoing_packet, value);
514: }
1.1 deraadt 515:
1.16 markus 516: /*
517: * Finalizes and sends the packet. If the encryption key has been set,
518: * encrypts the packet before sending.
519: */
1.14 markus 520:
1.68 itojun 521: static void
1.49 itojun 522: packet_send1(void)
1.1 deraadt 523: {
1.89 markus 524: u_char buf[8], *cp;
1.14 markus 525: int i, padding, len;
1.40 markus 526: u_int checksum;
1.115 avsm 527: u_int32_t rnd = 0;
1.14 markus 528:
1.16 markus 529: /*
530: * If using packet compression, compress the payload of the outgoing
531: * packet.
532: */
1.14 markus 533: if (packet_compression) {
534: buffer_clear(&compression_buffer);
535: /* Skip padding. */
536: buffer_consume(&outgoing_packet, 8);
537: /* padding */
538: buffer_append(&compression_buffer, "\0\0\0\0\0\0\0\0", 8);
539: buffer_compress(&outgoing_packet, &compression_buffer);
540: buffer_clear(&outgoing_packet);
541: buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer),
1.75 deraadt 542: buffer_len(&compression_buffer));
1.14 markus 543: }
544: /* Compute packet length without padding (add checksum, remove padding). */
545: len = buffer_len(&outgoing_packet) + 4 - 8;
546:
1.32 markus 547: /* Insert padding. Initialized to zero in packet_start1() */
1.14 markus 548: padding = 8 - len % 8;
1.88 markus 549: if (!send_context.plaintext) {
1.14 markus 550: cp = buffer_ptr(&outgoing_packet);
551: for (i = 0; i < padding; i++) {
552: if (i % 4 == 0)
1.115 avsm 553: rnd = arc4random();
554: cp[7 - i] = rnd & 0xff;
555: rnd >>= 8;
1.14 markus 556: }
557: }
558: buffer_consume(&outgoing_packet, 8 - padding);
559:
560: /* Add check bytes. */
1.83 stevesk 561: checksum = ssh_crc32(buffer_ptr(&outgoing_packet),
1.34 deraadt 562: buffer_len(&outgoing_packet));
1.131 djm 563: put_u32(buf, checksum);
1.14 markus 564: buffer_append(&outgoing_packet, buf, 4);
1.1 deraadt 565:
566: #ifdef PACKET_DEBUG
1.14 markus 567: fprintf(stderr, "packet_send plain: ");
568: buffer_dump(&outgoing_packet);
1.1 deraadt 569: #endif
570:
1.14 markus 571: /* Append to output. */
1.131 djm 572: put_u32(buf, len);
1.14 markus 573: buffer_append(&output, buf, 4);
1.76 stevesk 574: cp = buffer_append_space(&output, buffer_len(&outgoing_packet));
1.88 markus 575: cipher_crypt(&send_context, cp, buffer_ptr(&outgoing_packet),
1.75 deraadt 576: buffer_len(&outgoing_packet));
1.14 markus 577:
1.1 deraadt 578: #ifdef PACKET_DEBUG
1.14 markus 579: fprintf(stderr, "encrypted: ");
580: buffer_dump(&output);
1.1 deraadt 581: #endif
582:
1.14 markus 583: buffer_clear(&outgoing_packet);
1.1 deraadt 584:
1.16 markus 585: /*
1.120 djm 586: * Note that the packet is now only buffered in output. It won't be
1.16 markus 587: * actually sent until packet_write_wait or packet_write_poll is
588: * called.
589: */
1.1 deraadt 590: }
591:
1.91 markus 592: void
1.57 markus 593: set_newkeys(int mode)
594: {
595: Enc *enc;
596: Mac *mac;
597: Comp *comp;
598: CipherContext *cc;
1.105 markus 599: u_int64_t *max_blocks;
1.115 avsm 600: int crypt_type;
1.57 markus 601:
1.100 markus 602: debug2("set_newkeys: mode %d", mode);
1.57 markus 603:
1.88 markus 604: if (mode == MODE_OUT) {
605: cc = &send_context;
1.115 avsm 606: crypt_type = CIPHER_ENCRYPT;
1.105 markus 607: p_send.packets = p_send.blocks = 0;
608: max_blocks = &max_blocks_out;
1.88 markus 609: } else {
610: cc = &receive_context;
1.115 avsm 611: crypt_type = CIPHER_DECRYPT;
1.105 markus 612: p_read.packets = p_read.blocks = 0;
613: max_blocks = &max_blocks_in;
1.88 markus 614: }
1.57 markus 615: if (newkeys[mode] != NULL) {
1.100 markus 616: debug("set_newkeys: rekeying");
1.88 markus 617: cipher_cleanup(cc);
1.59 markus 618: enc = &newkeys[mode]->enc;
619: mac = &newkeys[mode]->mac;
620: comp = &newkeys[mode]->comp;
1.61 markus 621: memset(mac->key, 0, mac->key_len);
1.59 markus 622: xfree(enc->name);
623: xfree(enc->iv);
624: xfree(enc->key);
625: xfree(mac->name);
626: xfree(mac->key);
627: xfree(comp->name);
1.58 markus 628: xfree(newkeys[mode]);
1.57 markus 629: }
630: newkeys[mode] = kex_get_newkeys(mode);
631: if (newkeys[mode] == NULL)
632: fatal("newkeys: no keys for mode %d", mode);
633: enc = &newkeys[mode]->enc;
634: mac = &newkeys[mode]->mac;
635: comp = &newkeys[mode]->comp;
636: if (mac->md != NULL)
637: mac->enabled = 1;
638: DBG(debug("cipher_init_context: %d", mode));
1.88 markus 639: cipher_init(cc, enc->cipher, enc->key, enc->key_len,
1.115 avsm 640: enc->iv, enc->block_size, crypt_type);
1.91 markus 641: /* Deleting the keys does not gain extra security */
642: /* memset(enc->iv, 0, enc->block_size);
643: memset(enc->key, 0, enc->key_len); */
1.118 markus 644: if ((comp->type == COMP_ZLIB ||
645: (comp->type == COMP_DELAYED && after_authentication)) &&
646: comp->enabled == 0) {
1.60 markus 647: packet_init_compression();
648: if (mode == MODE_OUT)
649: buffer_compress_init_send(6);
650: else
651: buffer_compress_init_recv();
1.57 markus 652: comp->enabled = 1;
653: }
1.109 markus 654: /*
655: * The 2^(blocksize*2) limit is too expensive for 3DES,
656: * blowfish, etc, so enforce a 1GB limit for small blocksizes.
657: */
658: if (enc->block_size >= 16)
659: *max_blocks = (u_int64_t)1 << (enc->block_size*2);
660: else
661: *max_blocks = ((u_int64_t)1 << 30) / enc->block_size;
1.105 markus 662: if (rekey_limit)
663: *max_blocks = MIN(*max_blocks, rekey_limit / enc->block_size);
1.57 markus 664: }
665:
1.16 markus 666: /*
1.118 markus 667: * Delayed compression for SSH2 is enabled after authentication:
668: * This happans on the server side after a SSH2_MSG_USERAUTH_SUCCESS is sent,
669: * and on the client side after a SSH2_MSG_USERAUTH_SUCCESS is received.
670: */
671: static void
672: packet_enable_delayed_compress(void)
673: {
674: Comp *comp = NULL;
675: int mode;
676:
677: /*
678: * Remember that we are past the authentication step, so rekeying
679: * with COMP_DELAYED will turn on compression immediately.
680: */
681: after_authentication = 1;
682: for (mode = 0; mode < MODE_MAX; mode++) {
683: comp = &newkeys[mode]->comp;
684: if (comp && !comp->enabled && comp->type == COMP_DELAYED) {
1.119 markus 685: packet_init_compression();
1.118 markus 686: if (mode == MODE_OUT)
687: buffer_compress_init_send(6);
688: else
689: buffer_compress_init_recv();
690: comp->enabled = 1;
691: }
692: }
693: }
694:
695: /*
1.25 markus 696: * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue)
697: */
1.68 itojun 698: static void
1.105 markus 699: packet_send2_wrapped(void)
1.25 markus 700: {
1.89 markus 701: u_char type, *cp, *macbuf = NULL;
1.71 markus 702: u_char padlen, pad;
1.40 markus 703: u_int packet_length = 0;
1.71 markus 704: u_int i, len;
1.115 avsm 705: u_int32_t rnd = 0;
1.25 markus 706: Enc *enc = NULL;
707: Mac *mac = NULL;
708: Comp *comp = NULL;
709: int block_size;
710:
1.57 markus 711: if (newkeys[MODE_OUT] != NULL) {
712: enc = &newkeys[MODE_OUT]->enc;
713: mac = &newkeys[MODE_OUT]->mac;
714: comp = &newkeys[MODE_OUT]->comp;
1.25 markus 715: }
1.88 markus 716: block_size = enc ? enc->block_size : 8;
1.25 markus 717:
1.89 markus 718: cp = buffer_ptr(&outgoing_packet);
719: type = cp[5];
1.25 markus 720:
721: #ifdef PACKET_DEBUG
722: fprintf(stderr, "plain: ");
723: buffer_dump(&outgoing_packet);
724: #endif
725:
726: if (comp && comp->enabled) {
727: len = buffer_len(&outgoing_packet);
728: /* skip header, compress only payload */
729: buffer_consume(&outgoing_packet, 5);
730: buffer_clear(&compression_buffer);
731: buffer_compress(&outgoing_packet, &compression_buffer);
732: buffer_clear(&outgoing_packet);
733: buffer_append(&outgoing_packet, "\0\0\0\0\0", 5);
734: buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer),
735: buffer_len(&compression_buffer));
736: DBG(debug("compression: raw %d compressed %d", len,
737: buffer_len(&outgoing_packet)));
738: }
739:
740: /* sizeof (packet_len + pad_len + payload) */
741: len = buffer_len(&outgoing_packet);
742:
743: /*
744: * calc size of padding, alloc space, get random data,
745: * minimum padding is 4 bytes
746: */
747: padlen = block_size - (len % block_size);
748: if (padlen < 4)
749: padlen += block_size;
1.71 markus 750: if (extra_pad) {
751: /* will wrap if extra_pad+padlen > 255 */
752: extra_pad = roundup(extra_pad, block_size);
753: pad = extra_pad - ((len + padlen) % extra_pad);
1.93 markus 754: debug3("packet_send2: adding %d (len %d padlen %d extra_pad %d)",
1.71 markus 755: pad, len, padlen, extra_pad);
756: padlen += pad;
757: extra_pad = 0;
758: }
1.76 stevesk 759: cp = buffer_append_space(&outgoing_packet, padlen);
1.88 markus 760: if (enc && !send_context.plaintext) {
1.32 markus 761: /* random padding */
1.25 markus 762: for (i = 0; i < padlen; i++) {
763: if (i % 4 == 0)
1.115 avsm 764: rnd = arc4random();
765: cp[i] = rnd & 0xff;
766: rnd >>= 8;
1.25 markus 767: }
1.32 markus 768: } else {
769: /* clear padding */
770: memset(cp, 0, padlen);
1.25 markus 771: }
772: /* packet_length includes payload, padding and padding length field */
773: packet_length = buffer_len(&outgoing_packet) - 4;
1.89 markus 774: cp = buffer_ptr(&outgoing_packet);
1.131 djm 775: put_u32(cp, packet_length);
1.89 markus 776: cp[4] = padlen;
1.25 markus 777: DBG(debug("send: len %d (includes padlen %d)", packet_length+4, padlen));
778:
779: /* compute MAC over seqnr and packet(length fields, payload, padding) */
780: if (mac && mac->enabled) {
1.105 markus 781: macbuf = mac_compute(mac, p_send.seqnr,
1.83 stevesk 782: buffer_ptr(&outgoing_packet),
1.50 markus 783: buffer_len(&outgoing_packet));
1.105 markus 784: DBG(debug("done calc MAC out #%d", p_send.seqnr));
1.25 markus 785: }
786: /* encrypt packet and append to output buffer. */
1.76 stevesk 787: cp = buffer_append_space(&output, buffer_len(&outgoing_packet));
1.88 markus 788: cipher_crypt(&send_context, cp, buffer_ptr(&outgoing_packet),
1.25 markus 789: buffer_len(&outgoing_packet));
790: /* append unencrypted MAC */
791: if (mac && mac->enabled)
1.130 deraadt 792: buffer_append(&output, macbuf, mac->mac_len);
1.25 markus 793: #ifdef PACKET_DEBUG
794: fprintf(stderr, "encrypted: ");
795: buffer_dump(&output);
796: #endif
1.29 markus 797: /* increment sequence number for outgoing packets */
1.105 markus 798: if (++p_send.seqnr == 0)
1.106 itojun 799: logit("outgoing seqnr wraps around");
1.105 markus 800: if (++p_send.packets == 0)
801: if (!(datafellows & SSH_BUG_NOREKEY))
802: fatal("XXX too many packets with same key");
803: p_send.blocks += (packet_length + 4) / block_size;
1.25 markus 804: buffer_clear(&outgoing_packet);
805:
1.57 markus 806: if (type == SSH2_MSG_NEWKEYS)
807: set_newkeys(MODE_OUT);
1.118 markus 808: else if (type == SSH2_MSG_USERAUTH_SUCCESS && server_side)
809: packet_enable_delayed_compress();
1.25 markus 810: }
811:
1.105 markus 812: static void
813: packet_send2(void)
814: {
815: static int rekeying = 0;
816: struct packet *p;
817: u_char type, *cp;
818:
819: cp = buffer_ptr(&outgoing_packet);
820: type = cp[5];
821:
822: /* during rekeying we can only send key exchange messages */
823: if (rekeying) {
824: if (!((type >= SSH2_MSG_TRANSPORT_MIN) &&
825: (type <= SSH2_MSG_TRANSPORT_MAX))) {
826: debug("enqueue packet: %u", type);
827: p = xmalloc(sizeof(*p));
828: p->type = type;
829: memcpy(&p->payload, &outgoing_packet, sizeof(Buffer));
830: buffer_init(&outgoing_packet);
831: TAILQ_INSERT_TAIL(&outgoing, p, next);
832: return;
833: }
834: }
835:
836: /* rekeying starts with sending KEXINIT */
837: if (type == SSH2_MSG_KEXINIT)
838: rekeying = 1;
839:
840: packet_send2_wrapped();
841:
842: /* after a NEWKEYS message we can send the complete queue */
843: if (type == SSH2_MSG_NEWKEYS) {
844: rekeying = 0;
845: while ((p = TAILQ_FIRST(&outgoing))) {
846: type = p->type;
847: debug("dequeue packet: %u", type);
848: buffer_free(&outgoing_packet);
849: memcpy(&outgoing_packet, &p->payload,
850: sizeof(Buffer));
851: TAILQ_REMOVE(&outgoing, p, next);
852: xfree(p);
853: packet_send2_wrapped();
854: }
855: }
856: }
857:
1.25 markus 858: void
1.73 itojun 859: packet_send(void)
1.25 markus 860: {
1.62 markus 861: if (compat20)
1.25 markus 862: packet_send2();
863: else
864: packet_send1();
865: DBG(debug("packet_send done"));
866: }
867:
868: /*
1.16 markus 869: * Waits until a packet has been received, and returns its type. Note that
870: * no other data is processed until this returns, so this function should not
871: * be used during the interactive session.
872: */
1.1 deraadt 873:
1.2 provos 874: int
1.82 markus 875: packet_read_seqnr(u_int32_t *seqnr_p)
1.1 deraadt 876: {
1.14 markus 877: int type, len;
1.56 millert 878: fd_set *setp;
1.14 markus 879: char buf[8192];
1.25 markus 880: DBG(debug("packet_read()"));
1.14 markus 881:
1.127 djm 882: setp = (fd_set *)xcalloc(howmany(connection_in+1, NFDBITS),
1.56 millert 883: sizeof(fd_mask));
884:
1.14 markus 885: /* Since we are blocking, ensure that all written packets have been sent. */
886: packet_write_wait();
887:
888: /* Stay in the loop until we have received a complete packet. */
889: for (;;) {
890: /* Try to read a packet from the buffer. */
1.82 markus 891: type = packet_read_poll_seqnr(seqnr_p);
1.62 markus 892: if (!compat20 && (
1.32 markus 893: type == SSH_SMSG_SUCCESS
1.14 markus 894: || type == SSH_SMSG_FAILURE
895: || type == SSH_CMSG_EOF
1.32 markus 896: || type == SSH_CMSG_EXIT_CONFIRMATION))
1.79 markus 897: packet_check_eom();
1.14 markus 898: /* If we got a packet, return it. */
1.56 millert 899: if (type != SSH_MSG_NONE) {
900: xfree(setp);
1.14 markus 901: return type;
1.56 millert 902: }
1.16 markus 903: /*
904: * Otherwise, wait for some data to arrive, add it to the
905: * buffer, and try again.
906: */
1.56 millert 907: memset(setp, 0, howmany(connection_in + 1, NFDBITS) *
908: sizeof(fd_mask));
909: FD_SET(connection_in, setp);
1.16 markus 910:
1.14 markus 911: /* Wait for some data to arrive. */
1.56 millert 912: while (select(connection_in + 1, setp, NULL, NULL, NULL) == -1 &&
1.51 deraadt 913: (errno == EAGAIN || errno == EINTR))
914: ;
1.16 markus 915:
1.14 markus 916: /* Read data from the socket. */
917: len = read(connection_in, buf, sizeof(buf));
1.18 markus 918: if (len == 0) {
1.106 itojun 919: logit("Connection closed by %.200s", get_remote_ipaddr());
1.112 markus 920: cleanup_exit(255);
1.18 markus 921: }
1.14 markus 922: if (len < 0)
923: fatal("Read from socket failed: %.100s", strerror(errno));
924: /* Append it to the buffer. */
925: packet_process_incoming(buf, len);
926: }
927: /* NOTREACHED */
1.1 deraadt 928: }
929:
1.77 djm 930: int
1.82 markus 931: packet_read(void)
1.77 djm 932: {
1.82 markus 933: return packet_read_seqnr(NULL);
1.77 djm 934: }
935:
1.16 markus 936: /*
937: * Waits until a packet has been received, verifies that its type matches
938: * that given, and gives a fatal error and exits if there is a mismatch.
939: */
1.1 deraadt 940:
1.2 provos 941: void
1.82 markus 942: packet_read_expect(int expected_type)
1.1 deraadt 943: {
1.14 markus 944: int type;
1.1 deraadt 945:
1.82 markus 946: type = packet_read();
1.14 markus 947: if (type != expected_type)
948: packet_disconnect("Protocol error: expected packet type %d, got %d",
1.25 markus 949: expected_type, type);
1.1 deraadt 950: }
951:
952: /* Checks if a full packet is available in the data received so far via
1.14 markus 953: * packet_process_incoming. If so, reads the packet; otherwise returns
954: * SSH_MSG_NONE. This does not wait for data from the connection.
955: *
956: * SSH_MSG_DISCONNECT is handled specially here. Also,
957: * SSH_MSG_IGNORE messages are skipped by this function and are never returned
958: * to higher levels.
959: */
1.1 deraadt 960:
1.68 itojun 961: static int
1.82 markus 962: packet_read_poll1(void)
1.1 deraadt 963: {
1.40 markus 964: u_int len, padded_len;
1.89 markus 965: u_char *cp, type;
1.40 markus 966: u_int checksum, stored_checksum;
1.14 markus 967:
968: /* Check if input size is less than minimum packet size. */
969: if (buffer_len(&input) < 4 + 8)
970: return SSH_MSG_NONE;
971: /* Get length of incoming packet. */
1.89 markus 972: cp = buffer_ptr(&input);
1.131 djm 973: len = get_u32(cp);
1.14 markus 974: if (len < 1 + 2 + 2 || len > 256 * 1024)
1.98 markus 975: packet_disconnect("Bad packet length %u.", len);
1.14 markus 976: padded_len = (len + 8) & ~7;
977:
978: /* Check if the packet has been entirely received. */
979: if (buffer_len(&input) < 4 + padded_len)
980: return SSH_MSG_NONE;
981:
982: /* The entire packet is in buffer. */
983:
984: /* Consume packet length. */
985: buffer_consume(&input, 4);
986:
1.62 markus 987: /*
988: * Cryptographic attack detector for ssh
989: * (C)1998 CORE-SDI, Buenos Aires Argentina
990: * Ariel Futoransky(futo@core-sdi.com)
991: */
1.88 markus 992: if (!receive_context.plaintext &&
1.126 djm 993: detect_attack(buffer_ptr(&input), padded_len) == DEATTACK_DETECTED)
1.62 markus 994: packet_disconnect("crc32 compensation attack: network attack detected");
995:
996: /* Decrypt data to incoming_packet. */
1.14 markus 997: buffer_clear(&incoming_packet);
1.76 stevesk 998: cp = buffer_append_space(&incoming_packet, padded_len);
1.88 markus 999: cipher_crypt(&receive_context, cp, buffer_ptr(&input), padded_len);
1.62 markus 1000:
1.14 markus 1001: buffer_consume(&input, padded_len);
1.1 deraadt 1002:
1003: #ifdef PACKET_DEBUG
1.14 markus 1004: fprintf(stderr, "read_poll plain: ");
1005: buffer_dump(&incoming_packet);
1.1 deraadt 1006: #endif
1007:
1.14 markus 1008: /* Compute packet checksum. */
1.83 stevesk 1009: checksum = ssh_crc32(buffer_ptr(&incoming_packet),
1.25 markus 1010: buffer_len(&incoming_packet) - 4);
1.14 markus 1011:
1012: /* Skip padding. */
1013: buffer_consume(&incoming_packet, 8 - len % 8);
1014:
1015: /* Test check bytes. */
1016: if (len != buffer_len(&incoming_packet))
1.77 djm 1017: packet_disconnect("packet_read_poll1: len %d != buffer_len %d.",
1.25 markus 1018: len, buffer_len(&incoming_packet));
1.14 markus 1019:
1.89 markus 1020: cp = (u_char *)buffer_ptr(&incoming_packet) + len - 4;
1.131 djm 1021: stored_checksum = get_u32(cp);
1.14 markus 1022: if (checksum != stored_checksum)
1023: packet_disconnect("Corrupted check bytes on input.");
1024: buffer_consume_end(&incoming_packet, 4);
1025:
1026: if (packet_compression) {
1027: buffer_clear(&compression_buffer);
1028: buffer_uncompress(&incoming_packet, &compression_buffer);
1029: buffer_clear(&incoming_packet);
1030: buffer_append(&incoming_packet, buffer_ptr(&compression_buffer),
1.25 markus 1031: buffer_len(&compression_buffer));
1.14 markus 1032: }
1.62 markus 1033: type = buffer_get_char(&incoming_packet);
1.116 markus 1034: if (type < SSH_MSG_MIN || type > SSH_MSG_MAX)
1035: packet_disconnect("Invalid ssh1 packet type: %d", type);
1.62 markus 1036: return type;
1.1 deraadt 1037: }
1.14 markus 1038:
1.68 itojun 1039: static int
1.82 markus 1040: packet_read_poll2(u_int32_t *seqnr_p)
1.25 markus 1041: {
1.50 markus 1042: static u_int packet_length = 0;
1.40 markus 1043: u_int padlen, need;
1.89 markus 1044: u_char *macbuf, *cp, type;
1.117 djm 1045: u_int maclen, block_size;
1.25 markus 1046: Enc *enc = NULL;
1047: Mac *mac = NULL;
1048: Comp *comp = NULL;
1049:
1.57 markus 1050: if (newkeys[MODE_IN] != NULL) {
1051: enc = &newkeys[MODE_IN]->enc;
1052: mac = &newkeys[MODE_IN]->mac;
1053: comp = &newkeys[MODE_IN]->comp;
1.25 markus 1054: }
1055: maclen = mac && mac->enabled ? mac->mac_len : 0;
1.88 markus 1056: block_size = enc ? enc->block_size : 8;
1.25 markus 1057:
1058: if (packet_length == 0) {
1059: /*
1060: * check if input size is less than the cipher block size,
1061: * decrypt first block and extract length of incoming packet
1062: */
1063: if (buffer_len(&input) < block_size)
1064: return SSH_MSG_NONE;
1065: buffer_clear(&incoming_packet);
1.76 stevesk 1066: cp = buffer_append_space(&incoming_packet, block_size);
1.88 markus 1067: cipher_crypt(&receive_context, cp, buffer_ptr(&input),
1.25 markus 1068: block_size);
1.89 markus 1069: cp = buffer_ptr(&incoming_packet);
1.131 djm 1070: packet_length = get_u32(cp);
1.25 markus 1071: if (packet_length < 1 + 4 || packet_length > 256 * 1024) {
1.110 markus 1072: #ifdef PACKET_DEBUG
1.25 markus 1073: buffer_dump(&incoming_packet);
1.110 markus 1074: #endif
1.98 markus 1075: packet_disconnect("Bad packet length %u.", packet_length);
1.25 markus 1076: }
1.98 markus 1077: DBG(debug("input: packet len %u", packet_length+4));
1.25 markus 1078: buffer_consume(&input, block_size);
1079: }
1080: /* we have a partial packet of block_size bytes */
1081: need = 4 + packet_length - block_size;
1082: DBG(debug("partial packet %d, need %d, maclen %d", block_size,
1083: need, maclen));
1084: if (need % block_size != 0)
1085: fatal("padding error: need %d block %d mod %d",
1086: need, block_size, need % block_size);
1087: /*
1088: * check if the entire packet has been received and
1089: * decrypt into incoming_packet
1090: */
1091: if (buffer_len(&input) < need + maclen)
1092: return SSH_MSG_NONE;
1093: #ifdef PACKET_DEBUG
1094: fprintf(stderr, "read_poll enc/full: ");
1095: buffer_dump(&input);
1096: #endif
1.76 stevesk 1097: cp = buffer_append_space(&incoming_packet, need);
1.88 markus 1098: cipher_crypt(&receive_context, cp, buffer_ptr(&input), need);
1.25 markus 1099: buffer_consume(&input, need);
1100: /*
1101: * compute MAC over seqnr and packet,
1102: * increment sequence number for incoming packet
1103: */
1.29 markus 1104: if (mac && mac->enabled) {
1.105 markus 1105: macbuf = mac_compute(mac, p_read.seqnr,
1.83 stevesk 1106: buffer_ptr(&incoming_packet),
1.50 markus 1107: buffer_len(&incoming_packet));
1.25 markus 1108: if (memcmp(macbuf, buffer_ptr(&input), mac->mac_len) != 0)
1.36 markus 1109: packet_disconnect("Corrupted MAC on input.");
1.105 markus 1110: DBG(debug("MAC #%d ok", p_read.seqnr));
1.25 markus 1111: buffer_consume(&input, mac->mac_len);
1112: }
1.77 djm 1113: if (seqnr_p != NULL)
1.105 markus 1114: *seqnr_p = p_read.seqnr;
1115: if (++p_read.seqnr == 0)
1.106 itojun 1116: logit("incoming seqnr wraps around");
1.105 markus 1117: if (++p_read.packets == 0)
1118: if (!(datafellows & SSH_BUG_NOREKEY))
1119: fatal("XXX too many packets with same key");
1120: p_read.blocks += (packet_length + 4) / block_size;
1.25 markus 1121:
1122: /* get padlen */
1.76 stevesk 1123: cp = buffer_ptr(&incoming_packet);
1.89 markus 1124: padlen = cp[4];
1.25 markus 1125: DBG(debug("input: padlen %d", padlen));
1126: if (padlen < 4)
1127: packet_disconnect("Corrupted padlen %d on input.", padlen);
1128:
1129: /* skip packet size + padlen, discard padding */
1130: buffer_consume(&incoming_packet, 4 + 1);
1131: buffer_consume_end(&incoming_packet, padlen);
1132:
1133: DBG(debug("input: len before de-compress %d", buffer_len(&incoming_packet)));
1134: if (comp && comp->enabled) {
1135: buffer_clear(&compression_buffer);
1136: buffer_uncompress(&incoming_packet, &compression_buffer);
1137: buffer_clear(&incoming_packet);
1138: buffer_append(&incoming_packet, buffer_ptr(&compression_buffer),
1139: buffer_len(&compression_buffer));
1.97 deraadt 1140: DBG(debug("input: len after de-compress %d",
1141: buffer_len(&incoming_packet)));
1.25 markus 1142: }
1143: /*
1144: * get packet type, implies consume.
1145: * return length of payload (without type field)
1146: */
1.62 markus 1147: type = buffer_get_char(&incoming_packet);
1.116 markus 1148: if (type < SSH2_MSG_MIN || type >= SSH2_MSG_LOCAL_MIN)
1149: packet_disconnect("Invalid ssh2 packet type: %d", type);
1.57 markus 1150: if (type == SSH2_MSG_NEWKEYS)
1151: set_newkeys(MODE_IN);
1.118 markus 1152: else if (type == SSH2_MSG_USERAUTH_SUCCESS && !server_side)
1153: packet_enable_delayed_compress();
1.25 markus 1154: #ifdef PACKET_DEBUG
1.55 deraadt 1155: fprintf(stderr, "read/plain[%d]:\r\n", type);
1.25 markus 1156: buffer_dump(&incoming_packet);
1157: #endif
1.62 markus 1158: /* reset for next packet */
1159: packet_length = 0;
1160: return type;
1.25 markus 1161: }
1162:
1163: int
1.82 markus 1164: packet_read_poll_seqnr(u_int32_t *seqnr_p)
1.25 markus 1165: {
1.96 deraadt 1166: u_int reason, seqnr;
1.62 markus 1167: u_char type;
1.25 markus 1168: char *msg;
1.62 markus 1169:
1.25 markus 1170: for (;;) {
1.62 markus 1171: if (compat20) {
1.82 markus 1172: type = packet_read_poll2(seqnr_p);
1.62 markus 1173: if (type)
1.25 markus 1174: DBG(debug("received packet type %d", type));
1.74 deraadt 1175: switch (type) {
1.25 markus 1176: case SSH2_MSG_IGNORE:
1177: break;
1178: case SSH2_MSG_DEBUG:
1179: packet_get_char();
1180: msg = packet_get_string(NULL);
1181: debug("Remote: %.900s", msg);
1182: xfree(msg);
1183: msg = packet_get_string(NULL);
1184: xfree(msg);
1185: break;
1186: case SSH2_MSG_DISCONNECT:
1187: reason = packet_get_int();
1188: msg = packet_get_string(NULL);
1.106 itojun 1189: logit("Received disconnect from %s: %u: %.400s",
1.96 deraadt 1190: get_remote_ipaddr(), reason, msg);
1.25 markus 1191: xfree(msg);
1.112 markus 1192: cleanup_exit(255);
1.84 markus 1193: break;
1194: case SSH2_MSG_UNIMPLEMENTED:
1195: seqnr = packet_get_int();
1.96 deraadt 1196: debug("Received SSH2_MSG_UNIMPLEMENTED for %u",
1197: seqnr);
1.25 markus 1198: break;
1199: default:
1200: return type;
1.48 stevesk 1201: }
1.25 markus 1202: } else {
1.82 markus 1203: type = packet_read_poll1();
1.74 deraadt 1204: switch (type) {
1.25 markus 1205: case SSH_MSG_IGNORE:
1206: break;
1207: case SSH_MSG_DEBUG:
1208: msg = packet_get_string(NULL);
1209: debug("Remote: %.900s", msg);
1210: xfree(msg);
1211: break;
1212: case SSH_MSG_DISCONNECT:
1213: msg = packet_get_string(NULL);
1.106 itojun 1214: logit("Received disconnect from %s: %.400s",
1.96 deraadt 1215: get_remote_ipaddr(), msg);
1.112 markus 1216: cleanup_exit(255);
1.25 markus 1217: xfree(msg);
1218: break;
1219: default:
1.62 markus 1220: if (type)
1.25 markus 1221: DBG(debug("received packet type %d", type));
1222: return type;
1.48 stevesk 1223: }
1.25 markus 1224: }
1225: }
1.77 djm 1226: }
1227:
1228: int
1.82 markus 1229: packet_read_poll(void)
1.77 djm 1230: {
1.82 markus 1231: return packet_read_poll_seqnr(NULL);
1.25 markus 1232: }
1233:
1.16 markus 1234: /*
1235: * Buffers the given amount of input characters. This is intended to be used
1236: * together with packet_read_poll.
1237: */
1.1 deraadt 1238:
1.2 provos 1239: void
1.40 markus 1240: packet_process_incoming(const char *buf, u_int len)
1.1 deraadt 1241: {
1.14 markus 1242: buffer_append(&input, buf, len);
1.1 deraadt 1243: }
1244:
1245: /* Returns a character from the packet. */
1246:
1.40 markus 1247: u_int
1.73 itojun 1248: packet_get_char(void)
1.1 deraadt 1249: {
1.14 markus 1250: char ch;
1.97 deraadt 1251:
1.14 markus 1252: buffer_get(&incoming_packet, &ch, 1);
1.40 markus 1253: return (u_char) ch;
1.1 deraadt 1254: }
1255:
1256: /* Returns an integer from the packet data. */
1257:
1.40 markus 1258: u_int
1.73 itojun 1259: packet_get_int(void)
1.1 deraadt 1260: {
1.14 markus 1261: return buffer_get_int(&incoming_packet);
1.1 deraadt 1262: }
1263:
1.16 markus 1264: /*
1265: * Returns an arbitrary precision integer from the packet data. The integer
1266: * must have been initialized before this call.
1267: */
1.1 deraadt 1268:
1.2 provos 1269: void
1.80 markus 1270: packet_get_bignum(BIGNUM * value)
1.1 deraadt 1271: {
1.81 markus 1272: buffer_get_bignum(&incoming_packet, value);
1.24 markus 1273: }
1274:
1275: void
1.80 markus 1276: packet_get_bignum2(BIGNUM * value)
1.24 markus 1277: {
1.81 markus 1278: buffer_get_bignum2(&incoming_packet, value);
1.24 markus 1279: }
1280:
1.76 stevesk 1281: void *
1.117 djm 1282: packet_get_raw(u_int *length_ptr)
1.24 markus 1283: {
1.117 djm 1284: u_int bytes = buffer_len(&incoming_packet);
1.97 deraadt 1285:
1.24 markus 1286: if (length_ptr != NULL)
1287: *length_ptr = bytes;
1288: return buffer_ptr(&incoming_packet);
1.28 markus 1289: }
1290:
1291: int
1292: packet_remaining(void)
1293: {
1294: return buffer_len(&incoming_packet);
1.1 deraadt 1295: }
1296:
1.16 markus 1297: /*
1298: * Returns a string from the packet data. The string is allocated using
1299: * xmalloc; it is the responsibility of the calling program to free it when
1300: * no longer needed. The length_ptr argument may be NULL, or point to an
1301: * integer into which the length of the string is stored.
1302: */
1.1 deraadt 1303:
1.76 stevesk 1304: void *
1.40 markus 1305: packet_get_string(u_int *length_ptr)
1.1 deraadt 1306: {
1.14 markus 1307: return buffer_get_string(&incoming_packet, length_ptr);
1.1 deraadt 1308: }
1309:
1.16 markus 1310: /*
1311: * Sends a diagnostic message from the server to the client. This message
1312: * can be sent at any time (but not while constructing another message). The
1313: * message is printed immediately, but only if the client is being executed
1314: * in verbose mode. These messages are primarily intended to ease debugging
1315: * authentication problems. The length of the formatted message must not
1316: * exceed 1024 bytes. This will automatically call packet_write_wait.
1317: */
1.1 deraadt 1318:
1.2 provos 1319: void
1.14 markus 1320: packet_send_debug(const char *fmt,...)
1.1 deraadt 1321: {
1.14 markus 1322: char buf[1024];
1323: va_list args;
1.39 markus 1324:
1325: if (compat20 && (datafellows & SSH_BUG_DEBUG))
1326: return;
1.14 markus 1327:
1328: va_start(args, fmt);
1329: vsnprintf(buf, sizeof(buf), fmt, args);
1330: va_end(args);
1331:
1.30 markus 1332: if (compat20) {
1333: packet_start(SSH2_MSG_DEBUG);
1334: packet_put_char(0); /* bool: always display */
1335: packet_put_cstring(buf);
1336: packet_put_cstring("");
1337: } else {
1338: packet_start(SSH_MSG_DEBUG);
1339: packet_put_cstring(buf);
1340: }
1.14 markus 1341: packet_send();
1342: packet_write_wait();
1.1 deraadt 1343: }
1344:
1.16 markus 1345: /*
1346: * Logs the error plus constructs and sends a disconnect packet, closes the
1347: * connection, and exits. This function never returns. The error message
1348: * should not contain a newline. The length of the formatted message must
1349: * not exceed 1024 bytes.
1350: */
1.1 deraadt 1351:
1.2 provos 1352: void
1.14 markus 1353: packet_disconnect(const char *fmt,...)
1.1 deraadt 1354: {
1.14 markus 1355: char buf[1024];
1356: va_list args;
1357: static int disconnecting = 0;
1.97 deraadt 1358:
1.14 markus 1359: if (disconnecting) /* Guard against recursive invocations. */
1360: fatal("packet_disconnect called recursively.");
1361: disconnecting = 1;
1362:
1.16 markus 1363: /*
1364: * Format the message. Note that the caller must make sure the
1365: * message is of limited size.
1366: */
1.14 markus 1367: va_start(args, fmt);
1368: vsnprintf(buf, sizeof(buf), fmt, args);
1369: va_end(args);
1370:
1.99 markus 1371: /* Display the error locally */
1.106 itojun 1372: logit("Disconnecting: %.100s", buf);
1.99 markus 1373:
1.14 markus 1374: /* Send the disconnect message to the other side, and wait for it to get sent. */
1.25 markus 1375: if (compat20) {
1376: packet_start(SSH2_MSG_DISCONNECT);
1377: packet_put_int(SSH2_DISCONNECT_PROTOCOL_ERROR);
1378: packet_put_cstring(buf);
1379: packet_put_cstring("");
1380: } else {
1381: packet_start(SSH_MSG_DISCONNECT);
1.65 markus 1382: packet_put_cstring(buf);
1.25 markus 1383: }
1.14 markus 1384: packet_send();
1385: packet_write_wait();
1386:
1387: /* Stop listening for connections. */
1.67 markus 1388: channel_close_all();
1.14 markus 1389:
1390: /* Close the connection. */
1391: packet_close();
1.112 markus 1392: cleanup_exit(255);
1.1 deraadt 1393: }
1394:
1.16 markus 1395: /* Checks if there is any buffered output, and tries to write some of the output. */
1.1 deraadt 1396:
1.2 provos 1397: void
1.73 itojun 1398: packet_write_poll(void)
1.1 deraadt 1399: {
1.14 markus 1400: int len = buffer_len(&output);
1.97 deraadt 1401:
1.14 markus 1402: if (len > 0) {
1403: len = write(connection_out, buffer_ptr(&output), len);
1404: if (len <= 0) {
1405: if (errno == EAGAIN)
1406: return;
1407: else
1408: fatal("Write failed: %.100s", strerror(errno));
1409: }
1410: buffer_consume(&output, len);
1411: }
1.1 deraadt 1412: }
1413:
1.16 markus 1414: /*
1415: * Calls packet_write_poll repeatedly until all pending output data has been
1416: * written.
1417: */
1.1 deraadt 1418:
1.2 provos 1419: void
1.73 itojun 1420: packet_write_wait(void)
1.1 deraadt 1421: {
1.56 millert 1422: fd_set *setp;
1423:
1.127 djm 1424: setp = (fd_set *)xcalloc(howmany(connection_out + 1, NFDBITS),
1.56 millert 1425: sizeof(fd_mask));
1.14 markus 1426: packet_write_poll();
1427: while (packet_have_data_to_write()) {
1.56 millert 1428: memset(setp, 0, howmany(connection_out + 1, NFDBITS) *
1429: sizeof(fd_mask));
1430: FD_SET(connection_out, setp);
1431: while (select(connection_out + 1, NULL, setp, NULL, NULL) == -1 &&
1.51 deraadt 1432: (errno == EAGAIN || errno == EINTR))
1433: ;
1.14 markus 1434: packet_write_poll();
1435: }
1.56 millert 1436: xfree(setp);
1.1 deraadt 1437: }
1438:
1439: /* Returns true if there is buffered data to write to the connection. */
1440:
1.2 provos 1441: int
1.73 itojun 1442: packet_have_data_to_write(void)
1.1 deraadt 1443: {
1.14 markus 1444: return buffer_len(&output) != 0;
1.1 deraadt 1445: }
1446:
1447: /* Returns true if there is not too much data to write to the connection. */
1448:
1.2 provos 1449: int
1.73 itojun 1450: packet_not_very_much_data_to_write(void)
1.1 deraadt 1451: {
1.14 markus 1452: if (interactive_mode)
1453: return buffer_len(&output) < 16384;
1454: else
1455: return buffer_len(&output) < 128 * 1024;
1.1 deraadt 1456: }
1457:
1.102 markus 1458: static void
1.101 markus 1459: packet_set_tos(int interactive)
1460: {
1461: int tos = interactive ? IPTOS_LOWDELAY : IPTOS_THROUGHPUT;
1462:
1463: if (!packet_connection_is_on_socket() ||
1464: !packet_connection_is_ipv4())
1465: return;
1466: if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, &tos,
1467: sizeof(tos)) < 0)
1468: error("setsockopt IP_TOS %d: %.100s:",
1469: tos, strerror(errno));
1470: }
1471:
1.1 deraadt 1472: /* Informs that the current session is interactive. Sets IP flags for that. */
1473:
1.2 provos 1474: void
1.43 markus 1475: packet_set_interactive(int interactive)
1.1 deraadt 1476: {
1.43 markus 1477: static int called = 0;
1.44 markus 1478:
1.43 markus 1479: if (called)
1480: return;
1481: called = 1;
1.1 deraadt 1482:
1.14 markus 1483: /* Record that we are in interactive mode. */
1484: interactive_mode = interactive;
1.1 deraadt 1485:
1.19 markus 1486: /* Only set socket options if using a socket. */
1487: if (!packet_connection_is_on_socket())
1.14 markus 1488: return;
1.122 dtucker 1489: set_nodelay(connection_in);
1.101 markus 1490: packet_set_tos(interactive);
1.1 deraadt 1491: }
1492:
1493: /* Returns true if the current connection is interactive. */
1494:
1.2 provos 1495: int
1.73 itojun 1496: packet_is_interactive(void)
1.1 deraadt 1497: {
1.14 markus 1498: return interactive_mode;
1.12 markus 1499: }
1500:
1.113 deraadt 1501: int
1.108 markus 1502: packet_set_maxsize(u_int s)
1.12 markus 1503: {
1.14 markus 1504: static int called = 0;
1.97 deraadt 1505:
1.14 markus 1506: if (called) {
1.106 itojun 1507: logit("packet_set_maxsize: called twice: old %d new %d",
1.25 markus 1508: max_packet_size, s);
1.14 markus 1509: return -1;
1510: }
1511: if (s < 4 * 1024 || s > 1024 * 1024) {
1.106 itojun 1512: logit("packet_set_maxsize: bad size %d", s);
1.14 markus 1513: return -1;
1514: }
1.70 markus 1515: called = 1;
1.66 markus 1516: debug("packet_set_maxsize: setting to %d", s);
1.14 markus 1517: max_packet_size = s;
1518: return s;
1.53 markus 1519: }
1520:
1.71 markus 1521: /* roundup current message to pad bytes */
1522: void
1523: packet_add_padding(u_char pad)
1524: {
1525: extra_pad = pad;
1526: }
1527:
1.53 markus 1528: /*
1529: * 9.2. Ignored Data Message
1.61 markus 1530: *
1.53 markus 1531: * byte SSH_MSG_IGNORE
1532: * string data
1.61 markus 1533: *
1.53 markus 1534: * All implementations MUST understand (and ignore) this message at any
1535: * time (after receiving the protocol version). No implementation is
1536: * required to send them. This message can be used as an additional
1537: * protection measure against advanced traffic analysis techniques.
1538: */
1.54 markus 1539: void
1540: packet_send_ignore(int nbytes)
1541: {
1.115 avsm 1542: u_int32_t rnd = 0;
1.54 markus 1543: int i;
1544:
1545: packet_start(compat20 ? SSH2_MSG_IGNORE : SSH_MSG_IGNORE);
1.53 markus 1546: packet_put_int(nbytes);
1.75 deraadt 1547: for (i = 0; i < nbytes; i++) {
1.53 markus 1548: if (i % 4 == 0)
1.115 avsm 1549: rnd = arc4random();
1.129 deraadt 1550: packet_put_char((u_char)rnd & 0xff);
1.115 avsm 1551: rnd >>= 8;
1.53 markus 1552: }
1.105 markus 1553: }
1554:
1.113 deraadt 1555: #define MAX_PACKETS (1U<<31)
1.105 markus 1556: int
1557: packet_need_rekeying(void)
1558: {
1559: if (datafellows & SSH_BUG_NOREKEY)
1560: return 0;
1561: return
1562: (p_send.packets > MAX_PACKETS) ||
1563: (p_read.packets > MAX_PACKETS) ||
1564: (max_blocks_out && (p_send.blocks > max_blocks_out)) ||
1565: (max_blocks_in && (p_read.blocks > max_blocks_in));
1566: }
1567:
1568: void
1569: packet_set_rekey_limit(u_int32_t bytes)
1570: {
1571: rekey_limit = bytes;
1.118 markus 1572: }
1573:
1574: void
1575: packet_set_server(void)
1576: {
1577: server_side = 1;
1578: }
1579:
1580: void
1581: packet_set_authenticated(void)
1582: {
1583: after_authentication = 1;
1.1 deraadt 1584: }
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