1 /* $OpenBSD: packet.c,v 1.166 2009/06/27 09:29:06 andreas Exp $ */
3 * Author: Tatu Ylonen <ylo@cs.hut.fi>
4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
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.
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".
16 * SSH2 packet format added by Markus Friedl.
17 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
19 * Redistribution and use in source and binary forms, with or without
20 * modification, are permitted provided that the following conditions
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.
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.
42 #include <sys/types.h>
43 #include "openbsd-compat/sys-queue.h"
44 #include <sys/param.h>
45 #include <sys/socket.h>
46 #ifdef HAVE_SYS_TIME_H
47 # include <sys/time.h>
50 #include <netinet/in.h>
51 #include <netinet/ip.h>
52 #include <arpa/inet.h>
88 #define PACKET_MAX_SIZE (256 * 1024)
98 TAILQ_ENTRY(packet) next;
103 struct session_state {
105 * This variable contains the file descriptors used for
106 * communicating with the other side. connection_in is used for
107 * reading; connection_out for writing. These can be the same
108 * descriptor, in which case it is assumed to be a socket.
113 /* Protocol flags for the remote side. */
114 u_int remote_protocol_flags;
116 /* Encryption context for receiving data. Only used for decryption. */
117 CipherContext receive_context;
119 /* Encryption context for sending data. Only used for encryption. */
120 CipherContext send_context;
122 /* Buffer for raw input data from the socket. */
125 /* Buffer for raw output data going to the socket. */
128 /* Buffer for the partial outgoing packet being constructed. */
129 Buffer outgoing_packet;
131 /* Buffer for the incoming packet currently being processed. */
132 Buffer incoming_packet;
134 /* Scratch buffer for packet compression/decompression. */
135 Buffer compression_buffer;
136 int compression_buffer_ready;
139 * Flag indicating whether packet compression/decompression is
142 int packet_compression;
144 /* default maximum packet size */
145 u_int max_packet_size;
147 /* Flag indicating whether this module has been initialized. */
150 /* Set to true if the connection is interactive. */
151 int interactive_mode;
153 /* Set to true if we are the server side. */
156 /* Set to true if we are authenticated. */
157 int after_authentication;
159 int keep_alive_timeouts;
161 /* The maximum time that we will wait to send or receive a packet */
162 int packet_timeout_ms;
164 /* Session key information for Encryption and MAC */
165 Newkeys *newkeys[MODE_MAX];
166 struct packet_state p_read, p_send;
168 u_int64_t max_blocks_in, max_blocks_out;
169 u_int32_t rekey_limit;
171 /* Session key for protocol v1 */
172 u_char ssh1_key[SSH_SESSION_KEY_LENGTH];
175 /* roundup current message to extra_pad bytes */
178 /* XXX discard incoming data after MAC error */
179 u_int packet_discard;
180 Mac *packet_discard_mac;
182 /* Used in packet_read_poll2() */
185 /* Used in packet_send2 */
188 /* Used in packet_set_interactive */
189 int set_interactive_called;
191 /* Used in packet_set_maxsize */
192 int set_maxsize_called;
194 TAILQ_HEAD(, packet) outgoing;
197 static struct session_state *active_state, *backup_state;
199 static struct session_state *
200 alloc_session_state(void)
202 struct session_state *s = xcalloc(1, sizeof(*s));
204 s->connection_in = -1;
205 s->connection_out = -1;
206 s->max_packet_size = 32768;
207 s->packet_timeout_ms = -1;
212 * Sets the descriptors used for communication. Disables encryption until
213 * packet_set_encryption_key is called.
216 packet_set_connection(int fd_in, int fd_out)
218 Cipher *none = cipher_by_name("none");
221 fatal("packet_set_connection: cannot load cipher 'none'");
222 if (active_state == NULL)
223 active_state = alloc_session_state();
224 active_state->connection_in = fd_in;
225 active_state->connection_out = fd_out;
226 cipher_init(&active_state->send_context, none, (const u_char *)"",
227 0, NULL, 0, CIPHER_ENCRYPT);
228 cipher_init(&active_state->receive_context, none, (const u_char *)"",
229 0, NULL, 0, CIPHER_DECRYPT);
230 active_state->newkeys[MODE_IN] = active_state->newkeys[MODE_OUT] = NULL;
231 if (!active_state->initialized) {
232 active_state->initialized = 1;
233 buffer_init(&active_state->input);
234 buffer_init(&active_state->output);
235 buffer_init(&active_state->outgoing_packet);
236 buffer_init(&active_state->incoming_packet);
237 TAILQ_INIT(&active_state->outgoing);
238 active_state->p_send.packets = active_state->p_read.packets = 0;
243 packet_set_timeout(int timeout, int count)
245 if (timeout == 0 || count == 0) {
246 active_state->packet_timeout_ms = -1;
249 if ((INT_MAX / 1000) / count < timeout)
250 active_state->packet_timeout_ms = INT_MAX;
252 active_state->packet_timeout_ms = timeout * count * 1000;
256 packet_stop_discard(void)
258 if (active_state->packet_discard_mac) {
261 memset(buf, 'a', sizeof(buf));
262 while (buffer_len(&active_state->incoming_packet) <
264 buffer_append(&active_state->incoming_packet, buf,
266 (void) mac_compute(active_state->packet_discard_mac,
267 active_state->p_read.seqnr,
268 buffer_ptr(&active_state->incoming_packet),
271 logit("Finished discarding for %.200s", get_remote_ipaddr());
276 packet_start_discard(Enc *enc, Mac *mac, u_int packet_length, u_int discard)
278 if (enc == NULL || !cipher_is_cbc(enc->cipher))
279 packet_disconnect("Packet corrupt");
280 if (packet_length != PACKET_MAX_SIZE && mac && mac->enabled)
281 active_state->packet_discard_mac = mac;
282 if (buffer_len(&active_state->input) >= discard)
283 packet_stop_discard();
284 active_state->packet_discard = discard -
285 buffer_len(&active_state->input);
288 /* Returns 1 if remote host is connected via socket, 0 if not. */
291 packet_connection_is_on_socket(void)
293 struct sockaddr_storage from, to;
294 socklen_t fromlen, tolen;
296 /* filedescriptors in and out are the same, so it's a socket */
297 if (active_state->connection_in == active_state->connection_out)
299 fromlen = sizeof(from);
300 memset(&from, 0, sizeof(from));
301 if (getpeername(active_state->connection_in, (struct sockaddr *)&from,
305 memset(&to, 0, sizeof(to));
306 if (getpeername(active_state->connection_out, (struct sockaddr *)&to,
309 if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0)
311 if (from.ss_family != AF_INET && from.ss_family != AF_INET6)
317 * Exports an IV from the CipherContext required to export the key
318 * state back from the unprivileged child to the privileged parent
323 packet_get_keyiv(int mode, u_char *iv, u_int len)
327 if (mode == MODE_OUT)
328 cc = &active_state->send_context;
330 cc = &active_state->receive_context;
332 cipher_get_keyiv(cc, iv, len);
336 packet_get_keycontext(int mode, u_char *dat)
340 if (mode == MODE_OUT)
341 cc = &active_state->send_context;
343 cc = &active_state->receive_context;
345 return (cipher_get_keycontext(cc, dat));
349 packet_set_keycontext(int mode, u_char *dat)
353 if (mode == MODE_OUT)
354 cc = &active_state->send_context;
356 cc = &active_state->receive_context;
358 cipher_set_keycontext(cc, dat);
362 packet_get_keyiv_len(int mode)
366 if (mode == MODE_OUT)
367 cc = &active_state->send_context;
369 cc = &active_state->receive_context;
371 return (cipher_get_keyiv_len(cc));
375 packet_set_iv(int mode, u_char *dat)
379 if (mode == MODE_OUT)
380 cc = &active_state->send_context;
382 cc = &active_state->receive_context;
384 cipher_set_keyiv(cc, dat);
388 packet_get_ssh1_cipher(void)
390 return (cipher_get_number(active_state->receive_context.cipher));
394 packet_get_state(int mode, u_int32_t *seqnr, u_int64_t *blocks, u_int32_t *packets,
397 struct packet_state *state;
399 state = (mode == MODE_IN) ?
400 &active_state->p_read : &active_state->p_send;
402 *seqnr = state->seqnr;
404 *blocks = state->blocks;
406 *packets = state->packets;
408 *bytes = state->bytes;
412 packet_set_state(int mode, u_int32_t seqnr, u_int64_t blocks, u_int32_t packets,
415 struct packet_state *state;
417 state = (mode == MODE_IN) ?
418 &active_state->p_read : &active_state->p_send;
419 state->seqnr = seqnr;
420 state->blocks = blocks;
421 state->packets = packets;
422 state->bytes = bytes;
425 /* returns 1 if connection is via ipv4 */
428 packet_connection_is_ipv4(void)
430 struct sockaddr_storage to;
431 socklen_t tolen = sizeof(to);
433 memset(&to, 0, sizeof(to));
434 if (getsockname(active_state->connection_out, (struct sockaddr *)&to,
437 if (to.ss_family == AF_INET)
440 if (to.ss_family == AF_INET6 &&
441 IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)&to)->sin6_addr))
447 /* Sets the connection into non-blocking mode. */
450 packet_set_nonblocking(void)
452 /* Set the socket into non-blocking mode. */
453 set_nonblock(active_state->connection_in);
455 if (active_state->connection_out != active_state->connection_in)
456 set_nonblock(active_state->connection_out);
459 /* Returns the socket used for reading. */
462 packet_get_connection_in(void)
464 return active_state->connection_in;
467 /* Returns the descriptor used for writing. */
470 packet_get_connection_out(void)
472 return active_state->connection_out;
475 /* Closes the connection and clears and frees internal data structures. */
480 if (!active_state->initialized)
482 active_state->initialized = 0;
483 if (active_state->connection_in == active_state->connection_out) {
484 shutdown(active_state->connection_out, SHUT_RDWR);
485 close(active_state->connection_out);
487 close(active_state->connection_in);
488 close(active_state->connection_out);
490 buffer_free(&active_state->input);
491 buffer_free(&active_state->output);
492 buffer_free(&active_state->outgoing_packet);
493 buffer_free(&active_state->incoming_packet);
494 if (active_state->compression_buffer_ready) {
495 buffer_free(&active_state->compression_buffer);
496 buffer_compress_uninit();
498 cipher_cleanup(&active_state->send_context);
499 cipher_cleanup(&active_state->receive_context);
502 /* Sets remote side protocol flags. */
505 packet_set_protocol_flags(u_int protocol_flags)
507 active_state->remote_protocol_flags = protocol_flags;
510 /* Returns the remote protocol flags set earlier by the above function. */
513 packet_get_protocol_flags(void)
515 return active_state->remote_protocol_flags;
519 * Starts packet compression from the next packet on in both directions.
520 * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip.
524 packet_init_compression(void)
526 if (active_state->compression_buffer_ready == 1)
528 active_state->compression_buffer_ready = 1;
529 buffer_init(&active_state->compression_buffer);
533 packet_start_compression(int level)
535 if (active_state->packet_compression && !compat20)
536 fatal("Compression already enabled.");
537 active_state->packet_compression = 1;
538 packet_init_compression();
539 buffer_compress_init_send(level);
540 buffer_compress_init_recv();
544 * Causes any further packets to be encrypted using the given key. The same
545 * key is used for both sending and reception. However, both directions are
546 * encrypted independently of each other.
550 packet_set_encryption_key(const u_char *key, u_int keylen,
553 Cipher *cipher = cipher_by_number(number);
556 fatal("packet_set_encryption_key: unknown cipher number %d", number);
558 fatal("packet_set_encryption_key: keylen too small: %d", keylen);
559 if (keylen > SSH_SESSION_KEY_LENGTH)
560 fatal("packet_set_encryption_key: keylen too big: %d", keylen);
561 memcpy(active_state->ssh1_key, key, keylen);
562 active_state->ssh1_keylen = keylen;
563 cipher_init(&active_state->send_context, cipher, key, keylen, NULL,
565 cipher_init(&active_state->receive_context, cipher, key, keylen, NULL,
570 packet_get_encryption_key(u_char *key)
573 return (active_state->ssh1_keylen);
574 memcpy(key, active_state->ssh1_key, active_state->ssh1_keylen);
575 return (active_state->ssh1_keylen);
578 /* Start constructing a packet to send. */
580 packet_start(u_char type)
585 DBG(debug("packet_start[%d]", type));
586 len = compat20 ? 6 : 9;
587 memset(buf, 0, len - 1);
589 buffer_clear(&active_state->outgoing_packet);
590 buffer_append(&active_state->outgoing_packet, buf, len);
593 /* Append payload. */
595 packet_put_char(int value)
599 buffer_append(&active_state->outgoing_packet, &ch, 1);
603 packet_put_int(u_int value)
605 buffer_put_int(&active_state->outgoing_packet, value);
609 packet_put_int64(u_int64_t value)
611 buffer_put_int64(&active_state->outgoing_packet, value);
615 packet_put_string(const void *buf, u_int len)
617 buffer_put_string(&active_state->outgoing_packet, buf, len);
621 packet_put_cstring(const char *str)
623 buffer_put_cstring(&active_state->outgoing_packet, str);
627 packet_put_raw(const void *buf, u_int len)
629 buffer_append(&active_state->outgoing_packet, buf, len);
633 packet_put_bignum(BIGNUM * value)
635 buffer_put_bignum(&active_state->outgoing_packet, value);
639 packet_put_bignum2(BIGNUM * value)
641 buffer_put_bignum2(&active_state->outgoing_packet, value);
645 * Finalizes and sends the packet. If the encryption key has been set,
646 * encrypts the packet before sending.
658 * If using packet compression, compress the payload of the outgoing
661 if (active_state->packet_compression) {
662 buffer_clear(&active_state->compression_buffer);
664 buffer_consume(&active_state->outgoing_packet, 8);
666 buffer_append(&active_state->compression_buffer,
667 "\0\0\0\0\0\0\0\0", 8);
668 buffer_compress(&active_state->outgoing_packet,
669 &active_state->compression_buffer);
670 buffer_clear(&active_state->outgoing_packet);
671 buffer_append(&active_state->outgoing_packet,
672 buffer_ptr(&active_state->compression_buffer),
673 buffer_len(&active_state->compression_buffer));
675 /* Compute packet length without padding (add checksum, remove padding). */
676 len = buffer_len(&active_state->outgoing_packet) + 4 - 8;
678 /* Insert padding. Initialized to zero in packet_start1() */
679 padding = 8 - len % 8;
680 if (!active_state->send_context.plaintext) {
681 cp = buffer_ptr(&active_state->outgoing_packet);
682 for (i = 0; i < padding; i++) {
685 cp[7 - i] = rnd & 0xff;
689 buffer_consume(&active_state->outgoing_packet, 8 - padding);
691 /* Add check bytes. */
692 checksum = ssh_crc32(buffer_ptr(&active_state->outgoing_packet),
693 buffer_len(&active_state->outgoing_packet));
694 put_u32(buf, checksum);
695 buffer_append(&active_state->outgoing_packet, buf, 4);
698 fprintf(stderr, "packet_send plain: ");
699 buffer_dump(&active_state->outgoing_packet);
702 /* Append to output. */
704 buffer_append(&active_state->output, buf, 4);
705 cp = buffer_append_space(&active_state->output,
706 buffer_len(&active_state->outgoing_packet));
707 cipher_crypt(&active_state->send_context, cp,
708 buffer_ptr(&active_state->outgoing_packet),
709 buffer_len(&active_state->outgoing_packet));
712 fprintf(stderr, "encrypted: ");
713 buffer_dump(&active_state->output);
715 active_state->p_send.packets++;
716 active_state->p_send.bytes += len +
717 buffer_len(&active_state->outgoing_packet);
718 buffer_clear(&active_state->outgoing_packet);
721 * Note that the packet is now only buffered in output. It won't be
722 * actually sent until packet_write_wait or packet_write_poll is
728 set_newkeys(int mode)
734 u_int64_t *max_blocks;
737 debug2("set_newkeys: mode %d", mode);
739 if (mode == MODE_OUT) {
740 cc = &active_state->send_context;
741 crypt_type = CIPHER_ENCRYPT;
742 active_state->p_send.packets = active_state->p_send.blocks = 0;
743 max_blocks = &active_state->max_blocks_out;
745 cc = &active_state->receive_context;
746 crypt_type = CIPHER_DECRYPT;
747 active_state->p_read.packets = active_state->p_read.blocks = 0;
748 max_blocks = &active_state->max_blocks_in;
750 if (active_state->newkeys[mode] != NULL) {
751 debug("set_newkeys: rekeying");
753 enc = &active_state->newkeys[mode]->enc;
754 mac = &active_state->newkeys[mode]->mac;
755 comp = &active_state->newkeys[mode]->comp;
763 xfree(active_state->newkeys[mode]);
765 active_state->newkeys[mode] = kex_get_newkeys(mode);
766 if (active_state->newkeys[mode] == NULL)
767 fatal("newkeys: no keys for mode %d", mode);
768 enc = &active_state->newkeys[mode]->enc;
769 mac = &active_state->newkeys[mode]->mac;
770 comp = &active_state->newkeys[mode]->comp;
771 if (mac_init(mac) == 0)
773 DBG(debug("cipher_init_context: %d", mode));
774 cipher_init(cc, enc->cipher, enc->key, enc->key_len,
775 enc->iv, enc->block_size, crypt_type);
776 /* Deleting the keys does not gain extra security */
777 /* memset(enc->iv, 0, enc->block_size);
778 memset(enc->key, 0, enc->key_len);
779 memset(mac->key, 0, mac->key_len); */
780 if ((comp->type == COMP_ZLIB ||
781 (comp->type == COMP_DELAYED &&
782 active_state->after_authentication)) && comp->enabled == 0) {
783 packet_init_compression();
784 if (mode == MODE_OUT)
785 buffer_compress_init_send(6);
787 buffer_compress_init_recv();
791 * The 2^(blocksize*2) limit is too expensive for 3DES,
792 * blowfish, etc, so enforce a 1GB limit for small blocksizes.
794 if (enc->block_size >= 16)
795 *max_blocks = (u_int64_t)1 << (enc->block_size*2);
797 *max_blocks = ((u_int64_t)1 << 30) / enc->block_size;
798 if (active_state->rekey_limit)
799 *max_blocks = MIN(*max_blocks,
800 active_state->rekey_limit / enc->block_size);
804 * Delayed compression for SSH2 is enabled after authentication:
805 * This happens on the server side after a SSH2_MSG_USERAUTH_SUCCESS is sent,
806 * and on the client side after a SSH2_MSG_USERAUTH_SUCCESS is received.
809 packet_enable_delayed_compress(void)
815 * Remember that we are past the authentication step, so rekeying
816 * with COMP_DELAYED will turn on compression immediately.
818 active_state->after_authentication = 1;
819 for (mode = 0; mode < MODE_MAX; mode++) {
820 /* protocol error: USERAUTH_SUCCESS received before NEWKEYS */
821 if (active_state->newkeys[mode] == NULL)
823 comp = &active_state->newkeys[mode]->comp;
824 if (comp && !comp->enabled && comp->type == COMP_DELAYED) {
825 packet_init_compression();
826 if (mode == MODE_OUT)
827 buffer_compress_init_send(6);
829 buffer_compress_init_recv();
836 * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue)
839 packet_send2_wrapped(void)
841 u_char type, *cp, *macbuf = NULL;
843 u_int packet_length = 0;
851 if (active_state->newkeys[MODE_OUT] != NULL) {
852 enc = &active_state->newkeys[MODE_OUT]->enc;
853 mac = &active_state->newkeys[MODE_OUT]->mac;
854 comp = &active_state->newkeys[MODE_OUT]->comp;
856 block_size = enc ? enc->block_size : 8;
858 cp = buffer_ptr(&active_state->outgoing_packet);
862 fprintf(stderr, "plain: ");
863 buffer_dump(&active_state->outgoing_packet);
866 if (comp && comp->enabled) {
867 len = buffer_len(&active_state->outgoing_packet);
868 /* skip header, compress only payload */
869 buffer_consume(&active_state->outgoing_packet, 5);
870 buffer_clear(&active_state->compression_buffer);
871 buffer_compress(&active_state->outgoing_packet,
872 &active_state->compression_buffer);
873 buffer_clear(&active_state->outgoing_packet);
874 buffer_append(&active_state->outgoing_packet, "\0\0\0\0\0", 5);
875 buffer_append(&active_state->outgoing_packet,
876 buffer_ptr(&active_state->compression_buffer),
877 buffer_len(&active_state->compression_buffer));
878 DBG(debug("compression: raw %d compressed %d", len,
879 buffer_len(&active_state->outgoing_packet)));
882 /* sizeof (packet_len + pad_len + payload) */
883 len = buffer_len(&active_state->outgoing_packet);
886 * calc size of padding, alloc space, get random data,
887 * minimum padding is 4 bytes
889 padlen = block_size - (len % block_size);
891 padlen += block_size;
892 if (active_state->extra_pad) {
893 /* will wrap if extra_pad+padlen > 255 */
894 active_state->extra_pad =
895 roundup(active_state->extra_pad, block_size);
896 pad = active_state->extra_pad -
897 ((len + padlen) % active_state->extra_pad);
898 debug3("packet_send2: adding %d (len %d padlen %d extra_pad %d)",
899 pad, len, padlen, active_state->extra_pad);
901 active_state->extra_pad = 0;
903 cp = buffer_append_space(&active_state->outgoing_packet, padlen);
904 if (enc && !active_state->send_context.plaintext) {
906 for (i = 0; i < padlen; i++) {
914 memset(cp, 0, padlen);
916 /* packet_length includes payload, padding and padding length field */
917 packet_length = buffer_len(&active_state->outgoing_packet) - 4;
918 cp = buffer_ptr(&active_state->outgoing_packet);
919 put_u32(cp, packet_length);
921 DBG(debug("send: len %d (includes padlen %d)", packet_length+4, padlen));
923 /* compute MAC over seqnr and packet(length fields, payload, padding) */
924 if (mac && mac->enabled) {
925 macbuf = mac_compute(mac, active_state->p_send.seqnr,
926 buffer_ptr(&active_state->outgoing_packet),
927 buffer_len(&active_state->outgoing_packet));
928 DBG(debug("done calc MAC out #%d", active_state->p_send.seqnr));
930 /* encrypt packet and append to output buffer. */
931 cp = buffer_append_space(&active_state->output,
932 buffer_len(&active_state->outgoing_packet));
933 cipher_crypt(&active_state->send_context, cp,
934 buffer_ptr(&active_state->outgoing_packet),
935 buffer_len(&active_state->outgoing_packet));
936 /* append unencrypted MAC */
937 if (mac && mac->enabled)
938 buffer_append(&active_state->output, macbuf, mac->mac_len);
940 fprintf(stderr, "encrypted: ");
941 buffer_dump(&active_state->output);
943 /* increment sequence number for outgoing packets */
944 if (++active_state->p_send.seqnr == 0)
945 logit("outgoing seqnr wraps around");
946 if (++active_state->p_send.packets == 0)
947 if (!(datafellows & SSH_BUG_NOREKEY))
948 fatal("XXX too many packets with same key");
949 active_state->p_send.blocks += (packet_length + 4) / block_size;
950 active_state->p_send.bytes += packet_length + 4;
951 buffer_clear(&active_state->outgoing_packet);
953 if (type == SSH2_MSG_NEWKEYS)
954 set_newkeys(MODE_OUT);
955 else if (type == SSH2_MSG_USERAUTH_SUCCESS && active_state->server_side)
956 packet_enable_delayed_compress();
965 cp = buffer_ptr(&active_state->outgoing_packet);
968 /* during rekeying we can only send key exchange messages */
969 if (active_state->rekeying) {
970 if (!((type >= SSH2_MSG_TRANSPORT_MIN) &&
971 (type <= SSH2_MSG_TRANSPORT_MAX))) {
972 debug("enqueue packet: %u", type);
973 p = xmalloc(sizeof(*p));
975 memcpy(&p->payload, &active_state->outgoing_packet,
977 buffer_init(&active_state->outgoing_packet);
978 TAILQ_INSERT_TAIL(&active_state->outgoing, p, next);
983 /* rekeying starts with sending KEXINIT */
984 if (type == SSH2_MSG_KEXINIT)
985 active_state->rekeying = 1;
987 packet_send2_wrapped();
989 /* after a NEWKEYS message we can send the complete queue */
990 if (type == SSH2_MSG_NEWKEYS) {
991 active_state->rekeying = 0;
992 while ((p = TAILQ_FIRST(&active_state->outgoing))) {
994 debug("dequeue packet: %u", type);
995 buffer_free(&active_state->outgoing_packet);
996 memcpy(&active_state->outgoing_packet, &p->payload,
998 TAILQ_REMOVE(&active_state->outgoing, p, next);
1000 packet_send2_wrapped();
1012 DBG(debug("packet_send done"));
1016 * Waits until a packet has been received, and returns its type. Note that
1017 * no other data is processed until this returns, so this function should not
1018 * be used during the interactive session.
1022 packet_read_seqnr(u_int32_t *seqnr_p)
1024 int type, len, ret, ms_remain, cont;
1027 struct timeval timeout, start, *timeoutp = NULL;
1029 DBG(debug("packet_read()"));
1031 setp = (fd_set *)xcalloc(howmany(active_state->connection_in + 1,
1032 NFDBITS), sizeof(fd_mask));
1034 /* Since we are blocking, ensure that all written packets have been sent. */
1035 packet_write_wait();
1037 /* Stay in the loop until we have received a complete packet. */
1039 /* Try to read a packet from the buffer. */
1040 type = packet_read_poll_seqnr(seqnr_p);
1042 type == SSH_SMSG_SUCCESS
1043 || type == SSH_SMSG_FAILURE
1044 || type == SSH_CMSG_EOF
1045 || type == SSH_CMSG_EXIT_CONFIRMATION))
1047 /* If we got a packet, return it. */
1048 if (type != SSH_MSG_NONE) {
1053 * Otherwise, wait for some data to arrive, add it to the
1054 * buffer, and try again.
1056 memset(setp, 0, howmany(active_state->connection_in + 1,
1057 NFDBITS) * sizeof(fd_mask));
1058 FD_SET(active_state->connection_in, setp);
1060 if (active_state->packet_timeout_ms > 0) {
1061 ms_remain = active_state->packet_timeout_ms;
1062 timeoutp = &timeout;
1064 /* Wait for some data to arrive. */
1066 if (active_state->packet_timeout_ms != -1) {
1067 ms_to_timeval(&timeout, ms_remain);
1068 gettimeofday(&start, NULL);
1070 if ((ret = select(active_state->connection_in + 1, setp,
1071 NULL, NULL, timeoutp)) >= 0)
1073 if (errno != EAGAIN && errno != EINTR &&
1074 errno != EWOULDBLOCK)
1076 if (active_state->packet_timeout_ms == -1)
1078 ms_subtract_diff(&start, &ms_remain);
1079 if (ms_remain <= 0) {
1085 logit("Connection to %.200s timed out while "
1086 "waiting to read", get_remote_ipaddr());
1089 /* Read data from the socket. */
1092 len = roaming_read(active_state->connection_in, buf,
1093 sizeof(buf), &cont);
1094 } while (len == 0 && cont);
1096 logit("Connection closed by %.200s", get_remote_ipaddr());
1100 fatal("Read from socket failed: %.100s", strerror(errno));
1101 /* Append it to the buffer. */
1102 packet_process_incoming(buf, len);
1110 return packet_read_seqnr(NULL);
1114 * Waits until a packet has been received, verifies that its type matches
1115 * that given, and gives a fatal error and exits if there is a mismatch.
1119 packet_read_expect(int expected_type)
1123 type = packet_read();
1124 if (type != expected_type)
1125 packet_disconnect("Protocol error: expected packet type %d, got %d",
1126 expected_type, type);
1129 /* Checks if a full packet is available in the data received so far via
1130 * packet_process_incoming. If so, reads the packet; otherwise returns
1131 * SSH_MSG_NONE. This does not wait for data from the connection.
1133 * SSH_MSG_DISCONNECT is handled specially here. Also,
1134 * SSH_MSG_IGNORE messages are skipped by this function and are never returned
1139 packet_read_poll1(void)
1141 u_int len, padded_len;
1143 u_int checksum, stored_checksum;
1145 /* Check if input size is less than minimum packet size. */
1146 if (buffer_len(&active_state->input) < 4 + 8)
1147 return SSH_MSG_NONE;
1148 /* Get length of incoming packet. */
1149 cp = buffer_ptr(&active_state->input);
1151 if (len < 1 + 2 + 2 || len > 256 * 1024)
1152 packet_disconnect("Bad packet length %u.", len);
1153 padded_len = (len + 8) & ~7;
1155 /* Check if the packet has been entirely received. */
1156 if (buffer_len(&active_state->input) < 4 + padded_len)
1157 return SSH_MSG_NONE;
1159 /* The entire packet is in buffer. */
1161 /* Consume packet length. */
1162 buffer_consume(&active_state->input, 4);
1165 * Cryptographic attack detector for ssh
1166 * (C)1998 CORE-SDI, Buenos Aires Argentina
1167 * Ariel Futoransky(futo@core-sdi.com)
1169 if (!active_state->receive_context.plaintext) {
1170 switch (detect_attack(buffer_ptr(&active_state->input),
1172 case DEATTACK_DETECTED:
1173 packet_disconnect("crc32 compensation attack: "
1174 "network attack detected");
1175 case DEATTACK_DOS_DETECTED:
1176 packet_disconnect("deattack denial of "
1177 "service detected");
1181 /* Decrypt data to incoming_packet. */
1182 buffer_clear(&active_state->incoming_packet);
1183 cp = buffer_append_space(&active_state->incoming_packet, padded_len);
1184 cipher_crypt(&active_state->receive_context, cp,
1185 buffer_ptr(&active_state->input), padded_len);
1187 buffer_consume(&active_state->input, padded_len);
1190 fprintf(stderr, "read_poll plain: ");
1191 buffer_dump(&active_state->incoming_packet);
1194 /* Compute packet checksum. */
1195 checksum = ssh_crc32(buffer_ptr(&active_state->incoming_packet),
1196 buffer_len(&active_state->incoming_packet) - 4);
1199 buffer_consume(&active_state->incoming_packet, 8 - len % 8);
1201 /* Test check bytes. */
1202 if (len != buffer_len(&active_state->incoming_packet))
1203 packet_disconnect("packet_read_poll1: len %d != buffer_len %d.",
1204 len, buffer_len(&active_state->incoming_packet));
1206 cp = (u_char *)buffer_ptr(&active_state->incoming_packet) + len - 4;
1207 stored_checksum = get_u32(cp);
1208 if (checksum != stored_checksum)
1209 packet_disconnect("Corrupted check bytes on input.");
1210 buffer_consume_end(&active_state->incoming_packet, 4);
1212 if (active_state->packet_compression) {
1213 buffer_clear(&active_state->compression_buffer);
1214 buffer_uncompress(&active_state->incoming_packet,
1215 &active_state->compression_buffer);
1216 buffer_clear(&active_state->incoming_packet);
1217 buffer_append(&active_state->incoming_packet,
1218 buffer_ptr(&active_state->compression_buffer),
1219 buffer_len(&active_state->compression_buffer));
1221 active_state->p_read.packets++;
1222 active_state->p_read.bytes += padded_len + 4;
1223 type = buffer_get_char(&active_state->incoming_packet);
1224 if (type < SSH_MSG_MIN || type > SSH_MSG_MAX)
1225 packet_disconnect("Invalid ssh1 packet type: %d", type);
1230 packet_read_poll2(u_int32_t *seqnr_p)
1233 u_char *macbuf, *cp, type;
1234 u_int maclen, block_size;
1239 if (active_state->packet_discard)
1240 return SSH_MSG_NONE;
1242 if (active_state->newkeys[MODE_IN] != NULL) {
1243 enc = &active_state->newkeys[MODE_IN]->enc;
1244 mac = &active_state->newkeys[MODE_IN]->mac;
1245 comp = &active_state->newkeys[MODE_IN]->comp;
1247 maclen = mac && mac->enabled ? mac->mac_len : 0;
1248 block_size = enc ? enc->block_size : 8;
1250 if (active_state->packlen == 0) {
1252 * check if input size is less than the cipher block size,
1253 * decrypt first block and extract length of incoming packet
1255 if (buffer_len(&active_state->input) < block_size)
1256 return SSH_MSG_NONE;
1257 buffer_clear(&active_state->incoming_packet);
1258 cp = buffer_append_space(&active_state->incoming_packet,
1260 cipher_crypt(&active_state->receive_context, cp,
1261 buffer_ptr(&active_state->input), block_size);
1262 cp = buffer_ptr(&active_state->incoming_packet);
1263 active_state->packlen = get_u32(cp);
1264 if (active_state->packlen < 1 + 4 ||
1265 active_state->packlen > PACKET_MAX_SIZE) {
1267 buffer_dump(&active_state->incoming_packet);
1269 logit("Bad packet length %u.", active_state->packlen);
1270 packet_start_discard(enc, mac, active_state->packlen,
1272 return SSH_MSG_NONE;
1274 DBG(debug("input: packet len %u", active_state->packlen+4));
1275 buffer_consume(&active_state->input, block_size);
1277 /* we have a partial packet of block_size bytes */
1278 need = 4 + active_state->packlen - block_size;
1279 DBG(debug("partial packet %d, need %d, maclen %d", block_size,
1281 if (need % block_size != 0) {
1282 logit("padding error: need %d block %d mod %d",
1283 need, block_size, need % block_size);
1284 packet_start_discard(enc, mac, active_state->packlen,
1285 PACKET_MAX_SIZE - block_size);
1286 return SSH_MSG_NONE;
1289 * check if the entire packet has been received and
1290 * decrypt into incoming_packet
1292 if (buffer_len(&active_state->input) < need + maclen)
1293 return SSH_MSG_NONE;
1295 fprintf(stderr, "read_poll enc/full: ");
1296 buffer_dump(&active_state->input);
1298 cp = buffer_append_space(&active_state->incoming_packet, need);
1299 cipher_crypt(&active_state->receive_context, cp,
1300 buffer_ptr(&active_state->input), need);
1301 buffer_consume(&active_state->input, need);
1303 * compute MAC over seqnr and packet,
1304 * increment sequence number for incoming packet
1306 if (mac && mac->enabled) {
1307 macbuf = mac_compute(mac, active_state->p_read.seqnr,
1308 buffer_ptr(&active_state->incoming_packet),
1309 buffer_len(&active_state->incoming_packet));
1310 if (memcmp(macbuf, buffer_ptr(&active_state->input),
1311 mac->mac_len) != 0) {
1312 logit("Corrupted MAC on input.");
1313 if (need > PACKET_MAX_SIZE)
1314 fatal("internal error need %d", need);
1315 packet_start_discard(enc, mac, active_state->packlen,
1316 PACKET_MAX_SIZE - need);
1317 return SSH_MSG_NONE;
1320 DBG(debug("MAC #%d ok", active_state->p_read.seqnr));
1321 buffer_consume(&active_state->input, mac->mac_len);
1323 /* XXX now it's safe to use fatal/packet_disconnect */
1324 if (seqnr_p != NULL)
1325 *seqnr_p = active_state->p_read.seqnr;
1326 if (++active_state->p_read.seqnr == 0)
1327 logit("incoming seqnr wraps around");
1328 if (++active_state->p_read.packets == 0)
1329 if (!(datafellows & SSH_BUG_NOREKEY))
1330 fatal("XXX too many packets with same key");
1331 active_state->p_read.blocks += (active_state->packlen + 4) / block_size;
1332 active_state->p_read.bytes += active_state->packlen + 4;
1335 cp = buffer_ptr(&active_state->incoming_packet);
1337 DBG(debug("input: padlen %d", padlen));
1339 packet_disconnect("Corrupted padlen %d on input.", padlen);
1341 /* skip packet size + padlen, discard padding */
1342 buffer_consume(&active_state->incoming_packet, 4 + 1);
1343 buffer_consume_end(&active_state->incoming_packet, padlen);
1345 DBG(debug("input: len before de-compress %d",
1346 buffer_len(&active_state->incoming_packet)));
1347 if (comp && comp->enabled) {
1348 buffer_clear(&active_state->compression_buffer);
1349 buffer_uncompress(&active_state->incoming_packet,
1350 &active_state->compression_buffer);
1351 buffer_clear(&active_state->incoming_packet);
1352 buffer_append(&active_state->incoming_packet,
1353 buffer_ptr(&active_state->compression_buffer),
1354 buffer_len(&active_state->compression_buffer));
1355 DBG(debug("input: len after de-compress %d",
1356 buffer_len(&active_state->incoming_packet)));
1359 * get packet type, implies consume.
1360 * return length of payload (without type field)
1362 type = buffer_get_char(&active_state->incoming_packet);
1363 if (type < SSH2_MSG_MIN || type >= SSH2_MSG_LOCAL_MIN)
1364 packet_disconnect("Invalid ssh2 packet type: %d", type);
1365 if (type == SSH2_MSG_NEWKEYS)
1366 set_newkeys(MODE_IN);
1367 else if (type == SSH2_MSG_USERAUTH_SUCCESS &&
1368 !active_state->server_side)
1369 packet_enable_delayed_compress();
1371 fprintf(stderr, "read/plain[%d]:\r\n", type);
1372 buffer_dump(&active_state->incoming_packet);
1374 /* reset for next packet */
1375 active_state->packlen = 0;
1380 packet_read_poll_seqnr(u_int32_t *seqnr_p)
1382 u_int reason, seqnr;
1388 type = packet_read_poll2(seqnr_p);
1390 active_state->keep_alive_timeouts = 0;
1391 DBG(debug("received packet type %d", type));
1394 case SSH2_MSG_IGNORE:
1395 debug3("Received SSH2_MSG_IGNORE");
1397 case SSH2_MSG_DEBUG:
1399 msg = packet_get_string(NULL);
1400 debug("Remote: %.900s", msg);
1402 msg = packet_get_string(NULL);
1405 case SSH2_MSG_DISCONNECT:
1406 reason = packet_get_int();
1407 msg = packet_get_string(NULL);
1408 logit("Received disconnect from %s: %u: %.400s",
1409 get_remote_ipaddr(), reason, msg);
1413 case SSH2_MSG_UNIMPLEMENTED:
1414 seqnr = packet_get_int();
1415 debug("Received SSH2_MSG_UNIMPLEMENTED for %u",
1422 type = packet_read_poll1();
1424 case SSH_MSG_IGNORE:
1427 msg = packet_get_string(NULL);
1428 debug("Remote: %.900s", msg);
1431 case SSH_MSG_DISCONNECT:
1432 msg = packet_get_string(NULL);
1433 logit("Received disconnect from %s: %.400s",
1434 get_remote_ipaddr(), msg);
1439 DBG(debug("received packet type %d", type));
1447 packet_read_poll(void)
1449 return packet_read_poll_seqnr(NULL);
1453 * Buffers the given amount of input characters. This is intended to be used
1454 * together with packet_read_poll.
1458 packet_process_incoming(const char *buf, u_int len)
1460 if (active_state->packet_discard) {
1461 active_state->keep_alive_timeouts = 0; /* ?? */
1462 if (len >= active_state->packet_discard)
1463 packet_stop_discard();
1464 active_state->packet_discard -= len;
1467 buffer_append(&active_state->input, buf, len);
1470 /* Returns a character from the packet. */
1473 packet_get_char(void)
1477 buffer_get(&active_state->incoming_packet, &ch, 1);
1481 /* Returns an integer from the packet data. */
1484 packet_get_int(void)
1486 return buffer_get_int(&active_state->incoming_packet);
1489 /* Returns an 64 bit integer from the packet data. */
1492 packet_get_int64(void)
1494 return buffer_get_int64(&active_state->incoming_packet);
1498 * Returns an arbitrary precision integer from the packet data. The integer
1499 * must have been initialized before this call.
1503 packet_get_bignum(BIGNUM * value)
1505 buffer_get_bignum(&active_state->incoming_packet, value);
1509 packet_get_bignum2(BIGNUM * value)
1511 buffer_get_bignum2(&active_state->incoming_packet, value);
1515 packet_get_raw(u_int *length_ptr)
1517 u_int bytes = buffer_len(&active_state->incoming_packet);
1519 if (length_ptr != NULL)
1520 *length_ptr = bytes;
1521 return buffer_ptr(&active_state->incoming_packet);
1525 packet_remaining(void)
1527 return buffer_len(&active_state->incoming_packet);
1531 * Returns a string from the packet data. The string is allocated using
1532 * xmalloc; it is the responsibility of the calling program to free it when
1533 * no longer needed. The length_ptr argument may be NULL, or point to an
1534 * integer into which the length of the string is stored.
1538 packet_get_string(u_int *length_ptr)
1540 return buffer_get_string(&active_state->incoming_packet, length_ptr);
1544 packet_get_string_ptr(u_int *length_ptr)
1546 return buffer_get_string_ptr(&active_state->incoming_packet, length_ptr);
1550 * Sends a diagnostic message from the server to the client. This message
1551 * can be sent at any time (but not while constructing another message). The
1552 * message is printed immediately, but only if the client is being executed
1553 * in verbose mode. These messages are primarily intended to ease debugging
1554 * authentication problems. The length of the formatted message must not
1555 * exceed 1024 bytes. This will automatically call packet_write_wait.
1559 packet_send_debug(const char *fmt,...)
1564 if (compat20 && (datafellows & SSH_BUG_DEBUG))
1567 va_start(args, fmt);
1568 vsnprintf(buf, sizeof(buf), fmt, args);
1572 packet_start(SSH2_MSG_DEBUG);
1573 packet_put_char(0); /* bool: always display */
1574 packet_put_cstring(buf);
1575 packet_put_cstring("");
1577 packet_start(SSH_MSG_DEBUG);
1578 packet_put_cstring(buf);
1581 packet_write_wait();
1585 * Logs the error plus constructs and sends a disconnect packet, closes the
1586 * connection, and exits. This function never returns. The error message
1587 * should not contain a newline. The length of the formatted message must
1588 * not exceed 1024 bytes.
1592 packet_disconnect(const char *fmt,...)
1596 static int disconnecting = 0;
1598 if (disconnecting) /* Guard against recursive invocations. */
1599 fatal("packet_disconnect called recursively.");
1603 * Format the message. Note that the caller must make sure the
1604 * message is of limited size.
1606 va_start(args, fmt);
1607 vsnprintf(buf, sizeof(buf), fmt, args);
1610 /* Display the error locally */
1611 logit("Disconnecting: %.100s", buf);
1613 /* Send the disconnect message to the other side, and wait for it to get sent. */
1615 packet_start(SSH2_MSG_DISCONNECT);
1616 packet_put_int(SSH2_DISCONNECT_PROTOCOL_ERROR);
1617 packet_put_cstring(buf);
1618 packet_put_cstring("");
1620 packet_start(SSH_MSG_DISCONNECT);
1621 packet_put_cstring(buf);
1624 packet_write_wait();
1626 /* Stop listening for connections. */
1627 channel_close_all();
1629 /* Close the connection. */
1634 /* Checks if there is any buffered output, and tries to write some of the output. */
1637 packet_write_poll(void)
1639 int len = buffer_len(&active_state->output);
1644 len = roaming_write(active_state->connection_out,
1645 buffer_ptr(&active_state->output), len, &cont);
1647 if (errno == EINTR || errno == EAGAIN ||
1648 errno == EWOULDBLOCK)
1650 fatal("Write failed: %.100s", strerror(errno));
1652 if (len == 0 && !cont)
1653 fatal("Write connection closed");
1654 buffer_consume(&active_state->output, len);
1659 * Calls packet_write_poll repeatedly until all pending output data has been
1664 packet_write_wait(void)
1668 struct timeval start, timeout, *timeoutp = NULL;
1670 setp = (fd_set *)xcalloc(howmany(active_state->connection_out + 1,
1671 NFDBITS), sizeof(fd_mask));
1672 packet_write_poll();
1673 while (packet_have_data_to_write()) {
1674 memset(setp, 0, howmany(active_state->connection_out + 1,
1675 NFDBITS) * sizeof(fd_mask));
1676 FD_SET(active_state->connection_out, setp);
1678 if (active_state->packet_timeout_ms > 0) {
1679 ms_remain = active_state->packet_timeout_ms;
1680 timeoutp = &timeout;
1683 if (active_state->packet_timeout_ms != -1) {
1684 ms_to_timeval(&timeout, ms_remain);
1685 gettimeofday(&start, NULL);
1687 if ((ret = select(active_state->connection_out + 1,
1688 NULL, setp, NULL, timeoutp)) >= 0)
1690 if (errno != EAGAIN && errno != EINTR &&
1691 errno != EWOULDBLOCK)
1693 if (active_state->packet_timeout_ms == -1)
1695 ms_subtract_diff(&start, &ms_remain);
1696 if (ms_remain <= 0) {
1702 logit("Connection to %.200s timed out while "
1703 "waiting to write", get_remote_ipaddr());
1706 packet_write_poll();
1711 /* Returns true if there is buffered data to write to the connection. */
1714 packet_have_data_to_write(void)
1716 return buffer_len(&active_state->output) != 0;
1719 /* Returns true if there is not too much data to write to the connection. */
1722 packet_not_very_much_data_to_write(void)
1724 if (active_state->interactive_mode)
1725 return buffer_len(&active_state->output) < 16384;
1727 return buffer_len(&active_state->output) < 128 * 1024;
1731 packet_set_tos(int interactive)
1733 #if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN)
1734 int tos = interactive ? IPTOS_LOWDELAY : IPTOS_THROUGHPUT;
1736 if (!packet_connection_is_on_socket() ||
1737 !packet_connection_is_ipv4())
1739 if (setsockopt(active_state->connection_in, IPPROTO_IP, IP_TOS, &tos,
1741 error("setsockopt IP_TOS %d: %.100s:",
1742 tos, strerror(errno));
1746 /* Informs that the current session is interactive. Sets IP flags for that. */
1749 packet_set_interactive(int interactive)
1751 if (active_state->set_interactive_called)
1753 active_state->set_interactive_called = 1;
1755 /* Record that we are in interactive mode. */
1756 active_state->interactive_mode = interactive;
1758 /* Only set socket options if using a socket. */
1759 if (!packet_connection_is_on_socket())
1761 set_nodelay(active_state->connection_in);
1762 packet_set_tos(interactive);
1765 /* Returns true if the current connection is interactive. */
1768 packet_is_interactive(void)
1770 return active_state->interactive_mode;
1774 packet_set_maxsize(u_int s)
1776 if (active_state->set_maxsize_called) {
1777 logit("packet_set_maxsize: called twice: old %d new %d",
1778 active_state->max_packet_size, s);
1781 if (s < 4 * 1024 || s > 1024 * 1024) {
1782 logit("packet_set_maxsize: bad size %d", s);
1785 active_state->set_maxsize_called = 1;
1786 debug("packet_set_maxsize: setting to %d", s);
1787 active_state->max_packet_size = s;
1792 packet_inc_alive_timeouts(void)
1794 return ++active_state->keep_alive_timeouts;
1798 packet_set_alive_timeouts(int ka)
1800 active_state->keep_alive_timeouts = ka;
1804 packet_get_maxsize(void)
1806 return active_state->max_packet_size;
1809 /* roundup current message to pad bytes */
1811 packet_add_padding(u_char pad)
1813 active_state->extra_pad = pad;
1817 * 9.2. Ignored Data Message
1819 * byte SSH_MSG_IGNORE
1822 * All implementations MUST understand (and ignore) this message at any
1823 * time (after receiving the protocol version). No implementation is
1824 * required to send them. This message can be used as an additional
1825 * protection measure against advanced traffic analysis techniques.
1828 packet_send_ignore(int nbytes)
1833 packet_start(compat20 ? SSH2_MSG_IGNORE : SSH_MSG_IGNORE);
1834 packet_put_int(nbytes);
1835 for (i = 0; i < nbytes; i++) {
1838 packet_put_char((u_char)rnd & 0xff);
1843 #define MAX_PACKETS (1U<<31)
1845 packet_need_rekeying(void)
1847 if (datafellows & SSH_BUG_NOREKEY)
1850 (active_state->p_send.packets > MAX_PACKETS) ||
1851 (active_state->p_read.packets > MAX_PACKETS) ||
1852 (active_state->max_blocks_out &&
1853 (active_state->p_send.blocks > active_state->max_blocks_out)) ||
1854 (active_state->max_blocks_in &&
1855 (active_state->p_read.blocks > active_state->max_blocks_in));
1859 packet_set_rekey_limit(u_int32_t bytes)
1861 active_state->rekey_limit = bytes;
1865 packet_set_server(void)
1867 active_state->server_side = 1;
1871 packet_set_authenticated(void)
1873 active_state->after_authentication = 1;
1877 packet_get_input(void)
1879 return (void *)&active_state->input;
1883 packet_get_output(void)
1885 return (void *)&active_state->output;
1889 packet_get_newkeys(int mode)
1891 return (void *)active_state->newkeys[mode];
1895 * Save the state for the real connection, and use a separate state when
1896 * resuming a suspended connection.
1899 packet_backup_state(void)
1901 struct session_state *tmp;
1903 close(active_state->connection_in);
1904 active_state->connection_in = -1;
1905 close(active_state->connection_out);
1906 active_state->connection_out = -1;
1910 tmp = alloc_session_state();
1911 backup_state = active_state;
1916 * Swap in the old state when resuming a connecion.
1919 packet_restore_state(void)
1921 struct session_state *tmp;
1926 backup_state = active_state;
1928 active_state->connection_in = backup_state->connection_in;
1929 backup_state->connection_in = -1;
1930 active_state->connection_out = backup_state->connection_out;
1931 backup_state->connection_out = -1;
1932 len = buffer_len(&backup_state->input);
1934 buf = buffer_ptr(&backup_state->input);
1935 buffer_append(&active_state->input, buf, len);
1936 buffer_clear(&backup_state->input);
1937 add_recv_bytes(len);