1 /* $OpenBSD: packet.c,v 1.172 2010/11/13 23:27:50 djm 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,
395 u_int32_t *packets, u_int64_t *bytes)
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, int number)
552 Cipher *cipher = cipher_by_number(number);
555 fatal("packet_set_encryption_key: unknown cipher number %d", number);
557 fatal("packet_set_encryption_key: keylen too small: %d", keylen);
558 if (keylen > SSH_SESSION_KEY_LENGTH)
559 fatal("packet_set_encryption_key: keylen too big: %d", keylen);
560 memcpy(active_state->ssh1_key, key, keylen);
561 active_state->ssh1_keylen = keylen;
562 cipher_init(&active_state->send_context, cipher, key, keylen, NULL,
564 cipher_init(&active_state->receive_context, cipher, key, keylen, NULL,
569 packet_get_encryption_key(u_char *key)
572 return (active_state->ssh1_keylen);
573 memcpy(key, active_state->ssh1_key, active_state->ssh1_keylen);
574 return (active_state->ssh1_keylen);
577 /* Start constructing a packet to send. */
579 packet_start(u_char type)
584 DBG(debug("packet_start[%d]", type));
585 len = compat20 ? 6 : 9;
586 memset(buf, 0, len - 1);
588 buffer_clear(&active_state->outgoing_packet);
589 buffer_append(&active_state->outgoing_packet, buf, len);
592 /* Append payload. */
594 packet_put_char(int value)
598 buffer_append(&active_state->outgoing_packet, &ch, 1);
602 packet_put_int(u_int value)
604 buffer_put_int(&active_state->outgoing_packet, value);
608 packet_put_int64(u_int64_t value)
610 buffer_put_int64(&active_state->outgoing_packet, value);
614 packet_put_string(const void *buf, u_int len)
616 buffer_put_string(&active_state->outgoing_packet, buf, len);
620 packet_put_cstring(const char *str)
622 buffer_put_cstring(&active_state->outgoing_packet, str);
626 packet_put_raw(const void *buf, u_int len)
628 buffer_append(&active_state->outgoing_packet, buf, len);
632 packet_put_bignum(BIGNUM * value)
634 buffer_put_bignum(&active_state->outgoing_packet, value);
638 packet_put_bignum2(BIGNUM * value)
640 buffer_put_bignum2(&active_state->outgoing_packet, value);
643 #ifdef OPENSSL_HAS_ECC
645 packet_put_ecpoint(const EC_GROUP *curve, const EC_POINT *point)
647 buffer_put_ecpoint(&active_state->outgoing_packet, curve, point);
652 * Finalizes and sends the packet. If the encryption key has been set,
653 * encrypts the packet before sending.
665 * If using packet compression, compress the payload of the outgoing
668 if (active_state->packet_compression) {
669 buffer_clear(&active_state->compression_buffer);
671 buffer_consume(&active_state->outgoing_packet, 8);
673 buffer_append(&active_state->compression_buffer,
674 "\0\0\0\0\0\0\0\0", 8);
675 buffer_compress(&active_state->outgoing_packet,
676 &active_state->compression_buffer);
677 buffer_clear(&active_state->outgoing_packet);
678 buffer_append(&active_state->outgoing_packet,
679 buffer_ptr(&active_state->compression_buffer),
680 buffer_len(&active_state->compression_buffer));
682 /* Compute packet length without padding (add checksum, remove padding). */
683 len = buffer_len(&active_state->outgoing_packet) + 4 - 8;
685 /* Insert padding. Initialized to zero in packet_start1() */
686 padding = 8 - len % 8;
687 if (!active_state->send_context.plaintext) {
688 cp = buffer_ptr(&active_state->outgoing_packet);
689 for (i = 0; i < padding; i++) {
692 cp[7 - i] = rnd & 0xff;
696 buffer_consume(&active_state->outgoing_packet, 8 - padding);
698 /* Add check bytes. */
699 checksum = ssh_crc32(buffer_ptr(&active_state->outgoing_packet),
700 buffer_len(&active_state->outgoing_packet));
701 put_u32(buf, checksum);
702 buffer_append(&active_state->outgoing_packet, buf, 4);
705 fprintf(stderr, "packet_send plain: ");
706 buffer_dump(&active_state->outgoing_packet);
709 /* Append to output. */
711 buffer_append(&active_state->output, buf, 4);
712 cp = buffer_append_space(&active_state->output,
713 buffer_len(&active_state->outgoing_packet));
714 cipher_crypt(&active_state->send_context, cp,
715 buffer_ptr(&active_state->outgoing_packet),
716 buffer_len(&active_state->outgoing_packet));
719 fprintf(stderr, "encrypted: ");
720 buffer_dump(&active_state->output);
722 active_state->p_send.packets++;
723 active_state->p_send.bytes += len +
724 buffer_len(&active_state->outgoing_packet);
725 buffer_clear(&active_state->outgoing_packet);
728 * Note that the packet is now only buffered in output. It won't be
729 * actually sent until packet_write_wait or packet_write_poll is
735 set_newkeys(int mode)
741 u_int64_t *max_blocks;
744 debug2("set_newkeys: mode %d", mode);
746 if (mode == MODE_OUT) {
747 cc = &active_state->send_context;
748 crypt_type = CIPHER_ENCRYPT;
749 active_state->p_send.packets = active_state->p_send.blocks = 0;
750 max_blocks = &active_state->max_blocks_out;
752 cc = &active_state->receive_context;
753 crypt_type = CIPHER_DECRYPT;
754 active_state->p_read.packets = active_state->p_read.blocks = 0;
755 max_blocks = &active_state->max_blocks_in;
757 if (active_state->newkeys[mode] != NULL) {
758 debug("set_newkeys: rekeying");
760 enc = &active_state->newkeys[mode]->enc;
761 mac = &active_state->newkeys[mode]->mac;
762 comp = &active_state->newkeys[mode]->comp;
770 xfree(active_state->newkeys[mode]);
772 active_state->newkeys[mode] = kex_get_newkeys(mode);
773 if (active_state->newkeys[mode] == NULL)
774 fatal("newkeys: no keys for mode %d", mode);
775 enc = &active_state->newkeys[mode]->enc;
776 mac = &active_state->newkeys[mode]->mac;
777 comp = &active_state->newkeys[mode]->comp;
778 if (mac_init(mac) == 0)
780 DBG(debug("cipher_init_context: %d", mode));
781 cipher_init(cc, enc->cipher, enc->key, enc->key_len,
782 enc->iv, enc->block_size, crypt_type);
783 /* Deleting the keys does not gain extra security */
784 /* memset(enc->iv, 0, enc->block_size);
785 memset(enc->key, 0, enc->key_len);
786 memset(mac->key, 0, mac->key_len); */
787 if ((comp->type == COMP_ZLIB ||
788 (comp->type == COMP_DELAYED &&
789 active_state->after_authentication)) && comp->enabled == 0) {
790 packet_init_compression();
791 if (mode == MODE_OUT)
792 buffer_compress_init_send(6);
794 buffer_compress_init_recv();
798 * The 2^(blocksize*2) limit is too expensive for 3DES,
799 * blowfish, etc, so enforce a 1GB limit for small blocksizes.
801 if (enc->block_size >= 16)
802 *max_blocks = (u_int64_t)1 << (enc->block_size*2);
804 *max_blocks = ((u_int64_t)1 << 30) / enc->block_size;
805 if (active_state->rekey_limit)
806 *max_blocks = MIN(*max_blocks,
807 active_state->rekey_limit / enc->block_size);
811 * Delayed compression for SSH2 is enabled after authentication:
812 * This happens on the server side after a SSH2_MSG_USERAUTH_SUCCESS is sent,
813 * and on the client side after a SSH2_MSG_USERAUTH_SUCCESS is received.
816 packet_enable_delayed_compress(void)
822 * Remember that we are past the authentication step, so rekeying
823 * with COMP_DELAYED will turn on compression immediately.
825 active_state->after_authentication = 1;
826 for (mode = 0; mode < MODE_MAX; mode++) {
827 /* protocol error: USERAUTH_SUCCESS received before NEWKEYS */
828 if (active_state->newkeys[mode] == NULL)
830 comp = &active_state->newkeys[mode]->comp;
831 if (comp && !comp->enabled && comp->type == COMP_DELAYED) {
832 packet_init_compression();
833 if (mode == MODE_OUT)
834 buffer_compress_init_send(6);
836 buffer_compress_init_recv();
843 * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue)
846 packet_send2_wrapped(void)
848 u_char type, *cp, *macbuf = NULL;
850 u_int packet_length = 0;
858 if (active_state->newkeys[MODE_OUT] != NULL) {
859 enc = &active_state->newkeys[MODE_OUT]->enc;
860 mac = &active_state->newkeys[MODE_OUT]->mac;
861 comp = &active_state->newkeys[MODE_OUT]->comp;
863 block_size = enc ? enc->block_size : 8;
865 cp = buffer_ptr(&active_state->outgoing_packet);
869 fprintf(stderr, "plain: ");
870 buffer_dump(&active_state->outgoing_packet);
873 if (comp && comp->enabled) {
874 len = buffer_len(&active_state->outgoing_packet);
875 /* skip header, compress only payload */
876 buffer_consume(&active_state->outgoing_packet, 5);
877 buffer_clear(&active_state->compression_buffer);
878 buffer_compress(&active_state->outgoing_packet,
879 &active_state->compression_buffer);
880 buffer_clear(&active_state->outgoing_packet);
881 buffer_append(&active_state->outgoing_packet, "\0\0\0\0\0", 5);
882 buffer_append(&active_state->outgoing_packet,
883 buffer_ptr(&active_state->compression_buffer),
884 buffer_len(&active_state->compression_buffer));
885 DBG(debug("compression: raw %d compressed %d", len,
886 buffer_len(&active_state->outgoing_packet)));
889 /* sizeof (packet_len + pad_len + payload) */
890 len = buffer_len(&active_state->outgoing_packet);
893 * calc size of padding, alloc space, get random data,
894 * minimum padding is 4 bytes
896 padlen = block_size - (len % block_size);
898 padlen += block_size;
899 if (active_state->extra_pad) {
900 /* will wrap if extra_pad+padlen > 255 */
901 active_state->extra_pad =
902 roundup(active_state->extra_pad, block_size);
903 pad = active_state->extra_pad -
904 ((len + padlen) % active_state->extra_pad);
905 debug3("packet_send2: adding %d (len %d padlen %d extra_pad %d)",
906 pad, len, padlen, active_state->extra_pad);
908 active_state->extra_pad = 0;
910 cp = buffer_append_space(&active_state->outgoing_packet, padlen);
911 if (enc && !active_state->send_context.plaintext) {
913 for (i = 0; i < padlen; i++) {
921 memset(cp, 0, padlen);
923 /* packet_length includes payload, padding and padding length field */
924 packet_length = buffer_len(&active_state->outgoing_packet) - 4;
925 cp = buffer_ptr(&active_state->outgoing_packet);
926 put_u32(cp, packet_length);
928 DBG(debug("send: len %d (includes padlen %d)", packet_length+4, padlen));
930 /* compute MAC over seqnr and packet(length fields, payload, padding) */
931 if (mac && mac->enabled) {
932 macbuf = mac_compute(mac, active_state->p_send.seqnr,
933 buffer_ptr(&active_state->outgoing_packet),
934 buffer_len(&active_state->outgoing_packet));
935 DBG(debug("done calc MAC out #%d", active_state->p_send.seqnr));
937 /* encrypt packet and append to output buffer. */
938 cp = buffer_append_space(&active_state->output,
939 buffer_len(&active_state->outgoing_packet));
940 cipher_crypt(&active_state->send_context, cp,
941 buffer_ptr(&active_state->outgoing_packet),
942 buffer_len(&active_state->outgoing_packet));
943 /* append unencrypted MAC */
944 if (mac && mac->enabled)
945 buffer_append(&active_state->output, macbuf, mac->mac_len);
947 fprintf(stderr, "encrypted: ");
948 buffer_dump(&active_state->output);
950 /* increment sequence number for outgoing packets */
951 if (++active_state->p_send.seqnr == 0)
952 logit("outgoing seqnr wraps around");
953 if (++active_state->p_send.packets == 0)
954 if (!(datafellows & SSH_BUG_NOREKEY))
955 fatal("XXX too many packets with same key");
956 active_state->p_send.blocks += (packet_length + 4) / block_size;
957 active_state->p_send.bytes += packet_length + 4;
958 buffer_clear(&active_state->outgoing_packet);
960 if (type == SSH2_MSG_NEWKEYS)
961 set_newkeys(MODE_OUT);
962 else if (type == SSH2_MSG_USERAUTH_SUCCESS && active_state->server_side)
963 packet_enable_delayed_compress();
972 cp = buffer_ptr(&active_state->outgoing_packet);
975 /* during rekeying we can only send key exchange messages */
976 if (active_state->rekeying) {
977 if (!((type >= SSH2_MSG_TRANSPORT_MIN) &&
978 (type <= SSH2_MSG_TRANSPORT_MAX))) {
979 debug("enqueue packet: %u", type);
980 p = xmalloc(sizeof(*p));
982 memcpy(&p->payload, &active_state->outgoing_packet,
984 buffer_init(&active_state->outgoing_packet);
985 TAILQ_INSERT_TAIL(&active_state->outgoing, p, next);
990 /* rekeying starts with sending KEXINIT */
991 if (type == SSH2_MSG_KEXINIT)
992 active_state->rekeying = 1;
994 packet_send2_wrapped();
996 /* after a NEWKEYS message we can send the complete queue */
997 if (type == SSH2_MSG_NEWKEYS) {
998 active_state->rekeying = 0;
999 while ((p = TAILQ_FIRST(&active_state->outgoing))) {
1001 debug("dequeue packet: %u", type);
1002 buffer_free(&active_state->outgoing_packet);
1003 memcpy(&active_state->outgoing_packet, &p->payload,
1005 TAILQ_REMOVE(&active_state->outgoing, p, next);
1007 packet_send2_wrapped();
1019 DBG(debug("packet_send done"));
1023 * Waits until a packet has been received, and returns its type. Note that
1024 * no other data is processed until this returns, so this function should not
1025 * be used during the interactive session.
1029 packet_read_seqnr(u_int32_t *seqnr_p)
1031 int type, len, ret, ms_remain, cont;
1034 struct timeval timeout, start, *timeoutp = NULL;
1036 DBG(debug("packet_read()"));
1038 setp = (fd_set *)xcalloc(howmany(active_state->connection_in + 1,
1039 NFDBITS), sizeof(fd_mask));
1041 /* Since we are blocking, ensure that all written packets have been sent. */
1042 packet_write_wait();
1044 /* Stay in the loop until we have received a complete packet. */
1046 /* Try to read a packet from the buffer. */
1047 type = packet_read_poll_seqnr(seqnr_p);
1049 type == SSH_SMSG_SUCCESS
1050 || type == SSH_SMSG_FAILURE
1051 || type == SSH_CMSG_EOF
1052 || type == SSH_CMSG_EXIT_CONFIRMATION))
1054 /* If we got a packet, return it. */
1055 if (type != SSH_MSG_NONE) {
1060 * Otherwise, wait for some data to arrive, add it to the
1061 * buffer, and try again.
1063 memset(setp, 0, howmany(active_state->connection_in + 1,
1064 NFDBITS) * sizeof(fd_mask));
1065 FD_SET(active_state->connection_in, setp);
1067 if (active_state->packet_timeout_ms > 0) {
1068 ms_remain = active_state->packet_timeout_ms;
1069 timeoutp = &timeout;
1071 /* Wait for some data to arrive. */
1073 if (active_state->packet_timeout_ms != -1) {
1074 ms_to_timeval(&timeout, ms_remain);
1075 gettimeofday(&start, NULL);
1077 if ((ret = select(active_state->connection_in + 1, setp,
1078 NULL, NULL, timeoutp)) >= 0)
1080 if (errno != EAGAIN && errno != EINTR &&
1081 errno != EWOULDBLOCK)
1083 if (active_state->packet_timeout_ms == -1)
1085 ms_subtract_diff(&start, &ms_remain);
1086 if (ms_remain <= 0) {
1092 logit("Connection to %.200s timed out while "
1093 "waiting to read", get_remote_ipaddr());
1096 /* Read data from the socket. */
1099 len = roaming_read(active_state->connection_in, buf,
1100 sizeof(buf), &cont);
1101 } while (len == 0 && cont);
1103 logit("Connection closed by %.200s", get_remote_ipaddr());
1107 fatal("Read from socket failed: %.100s", strerror(errno));
1108 /* Append it to the buffer. */
1109 packet_process_incoming(buf, len);
1117 return packet_read_seqnr(NULL);
1121 * Waits until a packet has been received, verifies that its type matches
1122 * that given, and gives a fatal error and exits if there is a mismatch.
1126 packet_read_expect(int expected_type)
1130 type = packet_read();
1131 if (type != expected_type)
1132 packet_disconnect("Protocol error: expected packet type %d, got %d",
1133 expected_type, type);
1136 /* Checks if a full packet is available in the data received so far via
1137 * packet_process_incoming. If so, reads the packet; otherwise returns
1138 * SSH_MSG_NONE. This does not wait for data from the connection.
1140 * SSH_MSG_DISCONNECT is handled specially here. Also,
1141 * SSH_MSG_IGNORE messages are skipped by this function and are never returned
1146 packet_read_poll1(void)
1148 u_int len, padded_len;
1150 u_int checksum, stored_checksum;
1152 /* Check if input size is less than minimum packet size. */
1153 if (buffer_len(&active_state->input) < 4 + 8)
1154 return SSH_MSG_NONE;
1155 /* Get length of incoming packet. */
1156 cp = buffer_ptr(&active_state->input);
1158 if (len < 1 + 2 + 2 || len > 256 * 1024)
1159 packet_disconnect("Bad packet length %u.", len);
1160 padded_len = (len + 8) & ~7;
1162 /* Check if the packet has been entirely received. */
1163 if (buffer_len(&active_state->input) < 4 + padded_len)
1164 return SSH_MSG_NONE;
1166 /* The entire packet is in buffer. */
1168 /* Consume packet length. */
1169 buffer_consume(&active_state->input, 4);
1172 * Cryptographic attack detector for ssh
1173 * (C)1998 CORE-SDI, Buenos Aires Argentina
1174 * Ariel Futoransky(futo@core-sdi.com)
1176 if (!active_state->receive_context.plaintext) {
1177 switch (detect_attack(buffer_ptr(&active_state->input),
1179 case DEATTACK_DETECTED:
1180 packet_disconnect("crc32 compensation attack: "
1181 "network attack detected");
1182 case DEATTACK_DOS_DETECTED:
1183 packet_disconnect("deattack denial of "
1184 "service detected");
1188 /* Decrypt data to incoming_packet. */
1189 buffer_clear(&active_state->incoming_packet);
1190 cp = buffer_append_space(&active_state->incoming_packet, padded_len);
1191 cipher_crypt(&active_state->receive_context, cp,
1192 buffer_ptr(&active_state->input), padded_len);
1194 buffer_consume(&active_state->input, padded_len);
1197 fprintf(stderr, "read_poll plain: ");
1198 buffer_dump(&active_state->incoming_packet);
1201 /* Compute packet checksum. */
1202 checksum = ssh_crc32(buffer_ptr(&active_state->incoming_packet),
1203 buffer_len(&active_state->incoming_packet) - 4);
1206 buffer_consume(&active_state->incoming_packet, 8 - len % 8);
1208 /* Test check bytes. */
1209 if (len != buffer_len(&active_state->incoming_packet))
1210 packet_disconnect("packet_read_poll1: len %d != buffer_len %d.",
1211 len, buffer_len(&active_state->incoming_packet));
1213 cp = (u_char *)buffer_ptr(&active_state->incoming_packet) + len - 4;
1214 stored_checksum = get_u32(cp);
1215 if (checksum != stored_checksum)
1216 packet_disconnect("Corrupted check bytes on input.");
1217 buffer_consume_end(&active_state->incoming_packet, 4);
1219 if (active_state->packet_compression) {
1220 buffer_clear(&active_state->compression_buffer);
1221 buffer_uncompress(&active_state->incoming_packet,
1222 &active_state->compression_buffer);
1223 buffer_clear(&active_state->incoming_packet);
1224 buffer_append(&active_state->incoming_packet,
1225 buffer_ptr(&active_state->compression_buffer),
1226 buffer_len(&active_state->compression_buffer));
1228 active_state->p_read.packets++;
1229 active_state->p_read.bytes += padded_len + 4;
1230 type = buffer_get_char(&active_state->incoming_packet);
1231 if (type < SSH_MSG_MIN || type > SSH_MSG_MAX)
1232 packet_disconnect("Invalid ssh1 packet type: %d", type);
1237 packet_read_poll2(u_int32_t *seqnr_p)
1240 u_char *macbuf, *cp, type;
1241 u_int maclen, block_size;
1246 if (active_state->packet_discard)
1247 return SSH_MSG_NONE;
1249 if (active_state->newkeys[MODE_IN] != NULL) {
1250 enc = &active_state->newkeys[MODE_IN]->enc;
1251 mac = &active_state->newkeys[MODE_IN]->mac;
1252 comp = &active_state->newkeys[MODE_IN]->comp;
1254 maclen = mac && mac->enabled ? mac->mac_len : 0;
1255 block_size = enc ? enc->block_size : 8;
1257 if (active_state->packlen == 0) {
1259 * check if input size is less than the cipher block size,
1260 * decrypt first block and extract length of incoming packet
1262 if (buffer_len(&active_state->input) < block_size)
1263 return SSH_MSG_NONE;
1264 buffer_clear(&active_state->incoming_packet);
1265 cp = buffer_append_space(&active_state->incoming_packet,
1267 cipher_crypt(&active_state->receive_context, cp,
1268 buffer_ptr(&active_state->input), block_size);
1269 cp = buffer_ptr(&active_state->incoming_packet);
1270 active_state->packlen = get_u32(cp);
1271 if (active_state->packlen < 1 + 4 ||
1272 active_state->packlen > PACKET_MAX_SIZE) {
1274 buffer_dump(&active_state->incoming_packet);
1276 logit("Bad packet length %u.", active_state->packlen);
1277 packet_start_discard(enc, mac, active_state->packlen,
1279 return SSH_MSG_NONE;
1281 DBG(debug("input: packet len %u", active_state->packlen+4));
1282 buffer_consume(&active_state->input, block_size);
1284 /* we have a partial packet of block_size bytes */
1285 need = 4 + active_state->packlen - block_size;
1286 DBG(debug("partial packet %d, need %d, maclen %d", block_size,
1288 if (need % block_size != 0) {
1289 logit("padding error: need %d block %d mod %d",
1290 need, block_size, need % block_size);
1291 packet_start_discard(enc, mac, active_state->packlen,
1292 PACKET_MAX_SIZE - block_size);
1293 return SSH_MSG_NONE;
1296 * check if the entire packet has been received and
1297 * decrypt into incoming_packet
1299 if (buffer_len(&active_state->input) < need + maclen)
1300 return SSH_MSG_NONE;
1302 fprintf(stderr, "read_poll enc/full: ");
1303 buffer_dump(&active_state->input);
1305 cp = buffer_append_space(&active_state->incoming_packet, need);
1306 cipher_crypt(&active_state->receive_context, cp,
1307 buffer_ptr(&active_state->input), need);
1308 buffer_consume(&active_state->input, need);
1310 * compute MAC over seqnr and packet,
1311 * increment sequence number for incoming packet
1313 if (mac && mac->enabled) {
1314 macbuf = mac_compute(mac, active_state->p_read.seqnr,
1315 buffer_ptr(&active_state->incoming_packet),
1316 buffer_len(&active_state->incoming_packet));
1317 if (timingsafe_bcmp(macbuf, buffer_ptr(&active_state->input),
1318 mac->mac_len) != 0) {
1319 logit("Corrupted MAC on input.");
1320 if (need > PACKET_MAX_SIZE)
1321 fatal("internal error need %d", need);
1322 packet_start_discard(enc, mac, active_state->packlen,
1323 PACKET_MAX_SIZE - need);
1324 return SSH_MSG_NONE;
1327 DBG(debug("MAC #%d ok", active_state->p_read.seqnr));
1328 buffer_consume(&active_state->input, mac->mac_len);
1330 /* XXX now it's safe to use fatal/packet_disconnect */
1331 if (seqnr_p != NULL)
1332 *seqnr_p = active_state->p_read.seqnr;
1333 if (++active_state->p_read.seqnr == 0)
1334 logit("incoming seqnr wraps around");
1335 if (++active_state->p_read.packets == 0)
1336 if (!(datafellows & SSH_BUG_NOREKEY))
1337 fatal("XXX too many packets with same key");
1338 active_state->p_read.blocks += (active_state->packlen + 4) / block_size;
1339 active_state->p_read.bytes += active_state->packlen + 4;
1342 cp = buffer_ptr(&active_state->incoming_packet);
1344 DBG(debug("input: padlen %d", padlen));
1346 packet_disconnect("Corrupted padlen %d on input.", padlen);
1348 /* skip packet size + padlen, discard padding */
1349 buffer_consume(&active_state->incoming_packet, 4 + 1);
1350 buffer_consume_end(&active_state->incoming_packet, padlen);
1352 DBG(debug("input: len before de-compress %d",
1353 buffer_len(&active_state->incoming_packet)));
1354 if (comp && comp->enabled) {
1355 buffer_clear(&active_state->compression_buffer);
1356 buffer_uncompress(&active_state->incoming_packet,
1357 &active_state->compression_buffer);
1358 buffer_clear(&active_state->incoming_packet);
1359 buffer_append(&active_state->incoming_packet,
1360 buffer_ptr(&active_state->compression_buffer),
1361 buffer_len(&active_state->compression_buffer));
1362 DBG(debug("input: len after de-compress %d",
1363 buffer_len(&active_state->incoming_packet)));
1366 * get packet type, implies consume.
1367 * return length of payload (without type field)
1369 type = buffer_get_char(&active_state->incoming_packet);
1370 if (type < SSH2_MSG_MIN || type >= SSH2_MSG_LOCAL_MIN)
1371 packet_disconnect("Invalid ssh2 packet type: %d", type);
1372 if (type == SSH2_MSG_NEWKEYS)
1373 set_newkeys(MODE_IN);
1374 else if (type == SSH2_MSG_USERAUTH_SUCCESS &&
1375 !active_state->server_side)
1376 packet_enable_delayed_compress();
1378 fprintf(stderr, "read/plain[%d]:\r\n", type);
1379 buffer_dump(&active_state->incoming_packet);
1381 /* reset for next packet */
1382 active_state->packlen = 0;
1387 packet_read_poll_seqnr(u_int32_t *seqnr_p)
1389 u_int reason, seqnr;
1395 type = packet_read_poll2(seqnr_p);
1397 active_state->keep_alive_timeouts = 0;
1398 DBG(debug("received packet type %d", type));
1401 case SSH2_MSG_IGNORE:
1402 debug3("Received SSH2_MSG_IGNORE");
1404 case SSH2_MSG_DEBUG:
1406 msg = packet_get_string(NULL);
1407 debug("Remote: %.900s", msg);
1409 msg = packet_get_string(NULL);
1412 case SSH2_MSG_DISCONNECT:
1413 reason = packet_get_int();
1414 msg = packet_get_string(NULL);
1415 logit("Received disconnect from %s: %u: %.400s",
1416 get_remote_ipaddr(), reason, msg);
1420 case SSH2_MSG_UNIMPLEMENTED:
1421 seqnr = packet_get_int();
1422 debug("Received SSH2_MSG_UNIMPLEMENTED for %u",
1429 type = packet_read_poll1();
1431 case SSH_MSG_IGNORE:
1434 msg = packet_get_string(NULL);
1435 debug("Remote: %.900s", msg);
1438 case SSH_MSG_DISCONNECT:
1439 msg = packet_get_string(NULL);
1440 logit("Received disconnect from %s: %.400s",
1441 get_remote_ipaddr(), msg);
1446 DBG(debug("received packet type %d", type));
1454 packet_read_poll(void)
1456 return packet_read_poll_seqnr(NULL);
1460 * Buffers the given amount of input characters. This is intended to be used
1461 * together with packet_read_poll.
1465 packet_process_incoming(const char *buf, u_int len)
1467 if (active_state->packet_discard) {
1468 active_state->keep_alive_timeouts = 0; /* ?? */
1469 if (len >= active_state->packet_discard)
1470 packet_stop_discard();
1471 active_state->packet_discard -= len;
1474 buffer_append(&active_state->input, buf, len);
1477 /* Returns a character from the packet. */
1480 packet_get_char(void)
1484 buffer_get(&active_state->incoming_packet, &ch, 1);
1488 /* Returns an integer from the packet data. */
1491 packet_get_int(void)
1493 return buffer_get_int(&active_state->incoming_packet);
1496 /* Returns an 64 bit integer from the packet data. */
1499 packet_get_int64(void)
1501 return buffer_get_int64(&active_state->incoming_packet);
1505 * Returns an arbitrary precision integer from the packet data. The integer
1506 * must have been initialized before this call.
1510 packet_get_bignum(BIGNUM * value)
1512 buffer_get_bignum(&active_state->incoming_packet, value);
1516 packet_get_bignum2(BIGNUM * value)
1518 buffer_get_bignum2(&active_state->incoming_packet, value);
1521 #ifdef OPENSSL_HAS_ECC
1523 packet_get_ecpoint(const EC_GROUP *curve, EC_POINT *point)
1525 buffer_get_ecpoint(&active_state->incoming_packet, curve, point);
1530 packet_get_raw(u_int *length_ptr)
1532 u_int bytes = buffer_len(&active_state->incoming_packet);
1534 if (length_ptr != NULL)
1535 *length_ptr = bytes;
1536 return buffer_ptr(&active_state->incoming_packet);
1540 packet_remaining(void)
1542 return buffer_len(&active_state->incoming_packet);
1546 * Returns a string from the packet data. The string is allocated using
1547 * xmalloc; it is the responsibility of the calling program to free it when
1548 * no longer needed. The length_ptr argument may be NULL, or point to an
1549 * integer into which the length of the string is stored.
1553 packet_get_string(u_int *length_ptr)
1555 return buffer_get_string(&active_state->incoming_packet, length_ptr);
1559 packet_get_string_ptr(u_int *length_ptr)
1561 return buffer_get_string_ptr(&active_state->incoming_packet, length_ptr);
1564 /* Ensures the returned string has no embedded \0 characters in it. */
1566 packet_get_cstring(u_int *length_ptr)
1568 return buffer_get_cstring(&active_state->incoming_packet, length_ptr);
1572 * Sends a diagnostic message from the server to the client. This message
1573 * can be sent at any time (but not while constructing another message). The
1574 * message is printed immediately, but only if the client is being executed
1575 * in verbose mode. These messages are primarily intended to ease debugging
1576 * authentication problems. The length of the formatted message must not
1577 * exceed 1024 bytes. This will automatically call packet_write_wait.
1581 packet_send_debug(const char *fmt,...)
1586 if (compat20 && (datafellows & SSH_BUG_DEBUG))
1589 va_start(args, fmt);
1590 vsnprintf(buf, sizeof(buf), fmt, args);
1594 packet_start(SSH2_MSG_DEBUG);
1595 packet_put_char(0); /* bool: always display */
1596 packet_put_cstring(buf);
1597 packet_put_cstring("");
1599 packet_start(SSH_MSG_DEBUG);
1600 packet_put_cstring(buf);
1603 packet_write_wait();
1607 * Logs the error plus constructs and sends a disconnect packet, closes the
1608 * connection, and exits. This function never returns. The error message
1609 * should not contain a newline. The length of the formatted message must
1610 * not exceed 1024 bytes.
1614 packet_disconnect(const char *fmt,...)
1618 static int disconnecting = 0;
1620 if (disconnecting) /* Guard against recursive invocations. */
1621 fatal("packet_disconnect called recursively.");
1625 * Format the message. Note that the caller must make sure the
1626 * message is of limited size.
1628 va_start(args, fmt);
1629 vsnprintf(buf, sizeof(buf), fmt, args);
1632 /* Display the error locally */
1633 logit("Disconnecting: %.100s", buf);
1635 /* Send the disconnect message to the other side, and wait for it to get sent. */
1637 packet_start(SSH2_MSG_DISCONNECT);
1638 packet_put_int(SSH2_DISCONNECT_PROTOCOL_ERROR);
1639 packet_put_cstring(buf);
1640 packet_put_cstring("");
1642 packet_start(SSH_MSG_DISCONNECT);
1643 packet_put_cstring(buf);
1646 packet_write_wait();
1648 /* Stop listening for connections. */
1649 channel_close_all();
1651 /* Close the connection. */
1656 /* Checks if there is any buffered output, and tries to write some of the output. */
1659 packet_write_poll(void)
1661 int len = buffer_len(&active_state->output);
1666 len = roaming_write(active_state->connection_out,
1667 buffer_ptr(&active_state->output), len, &cont);
1669 if (errno == EINTR || errno == EAGAIN ||
1670 errno == EWOULDBLOCK)
1672 fatal("Write failed: %.100s", strerror(errno));
1674 if (len == 0 && !cont)
1675 fatal("Write connection closed");
1676 buffer_consume(&active_state->output, len);
1681 * Calls packet_write_poll repeatedly until all pending output data has been
1686 packet_write_wait(void)
1690 struct timeval start, timeout, *timeoutp = NULL;
1692 setp = (fd_set *)xcalloc(howmany(active_state->connection_out + 1,
1693 NFDBITS), sizeof(fd_mask));
1694 packet_write_poll();
1695 while (packet_have_data_to_write()) {
1696 memset(setp, 0, howmany(active_state->connection_out + 1,
1697 NFDBITS) * sizeof(fd_mask));
1698 FD_SET(active_state->connection_out, setp);
1700 if (active_state->packet_timeout_ms > 0) {
1701 ms_remain = active_state->packet_timeout_ms;
1702 timeoutp = &timeout;
1705 if (active_state->packet_timeout_ms != -1) {
1706 ms_to_timeval(&timeout, ms_remain);
1707 gettimeofday(&start, NULL);
1709 if ((ret = select(active_state->connection_out + 1,
1710 NULL, setp, NULL, timeoutp)) >= 0)
1712 if (errno != EAGAIN && errno != EINTR &&
1713 errno != EWOULDBLOCK)
1715 if (active_state->packet_timeout_ms == -1)
1717 ms_subtract_diff(&start, &ms_remain);
1718 if (ms_remain <= 0) {
1724 logit("Connection to %.200s timed out while "
1725 "waiting to write", get_remote_ipaddr());
1728 packet_write_poll();
1733 /* Returns true if there is buffered data to write to the connection. */
1736 packet_have_data_to_write(void)
1738 return buffer_len(&active_state->output) != 0;
1741 /* Returns true if there is not too much data to write to the connection. */
1744 packet_not_very_much_data_to_write(void)
1746 if (active_state->interactive_mode)
1747 return buffer_len(&active_state->output) < 16384;
1749 return buffer_len(&active_state->output) < 128 * 1024;
1753 packet_set_tos(int tos)
1755 #if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN)
1756 if (!packet_connection_is_on_socket() ||
1757 !packet_connection_is_ipv4())
1759 debug3("%s: set IP_TOS 0x%02x", __func__, tos);
1760 if (setsockopt(active_state->connection_in, IPPROTO_IP, IP_TOS, &tos,
1762 error("setsockopt IP_TOS %d: %.100s:",
1763 tos, strerror(errno));
1767 /* Informs that the current session is interactive. Sets IP flags for that. */
1770 packet_set_interactive(int interactive, int qos_interactive, int qos_bulk)
1772 if (active_state->set_interactive_called)
1774 active_state->set_interactive_called = 1;
1776 /* Record that we are in interactive mode. */
1777 active_state->interactive_mode = interactive;
1779 /* Only set socket options if using a socket. */
1780 if (!packet_connection_is_on_socket())
1782 set_nodelay(active_state->connection_in);
1783 packet_set_tos(interactive ? qos_interactive : qos_bulk);
1786 /* Returns true if the current connection is interactive. */
1789 packet_is_interactive(void)
1791 return active_state->interactive_mode;
1795 packet_set_maxsize(u_int s)
1797 if (active_state->set_maxsize_called) {
1798 logit("packet_set_maxsize: called twice: old %d new %d",
1799 active_state->max_packet_size, s);
1802 if (s < 4 * 1024 || s > 1024 * 1024) {
1803 logit("packet_set_maxsize: bad size %d", s);
1806 active_state->set_maxsize_called = 1;
1807 debug("packet_set_maxsize: setting to %d", s);
1808 active_state->max_packet_size = s;
1813 packet_inc_alive_timeouts(void)
1815 return ++active_state->keep_alive_timeouts;
1819 packet_set_alive_timeouts(int ka)
1821 active_state->keep_alive_timeouts = ka;
1825 packet_get_maxsize(void)
1827 return active_state->max_packet_size;
1830 /* roundup current message to pad bytes */
1832 packet_add_padding(u_char pad)
1834 active_state->extra_pad = pad;
1838 * 9.2. Ignored Data Message
1840 * byte SSH_MSG_IGNORE
1843 * All implementations MUST understand (and ignore) this message at any
1844 * time (after receiving the protocol version). No implementation is
1845 * required to send them. This message can be used as an additional
1846 * protection measure against advanced traffic analysis techniques.
1849 packet_send_ignore(int nbytes)
1854 packet_start(compat20 ? SSH2_MSG_IGNORE : SSH_MSG_IGNORE);
1855 packet_put_int(nbytes);
1856 for (i = 0; i < nbytes; i++) {
1859 packet_put_char((u_char)rnd & 0xff);
1864 #define MAX_PACKETS (1U<<31)
1866 packet_need_rekeying(void)
1868 if (datafellows & SSH_BUG_NOREKEY)
1871 (active_state->p_send.packets > MAX_PACKETS) ||
1872 (active_state->p_read.packets > MAX_PACKETS) ||
1873 (active_state->max_blocks_out &&
1874 (active_state->p_send.blocks > active_state->max_blocks_out)) ||
1875 (active_state->max_blocks_in &&
1876 (active_state->p_read.blocks > active_state->max_blocks_in));
1880 packet_set_rekey_limit(u_int32_t bytes)
1882 active_state->rekey_limit = bytes;
1886 packet_set_server(void)
1888 active_state->server_side = 1;
1892 packet_set_authenticated(void)
1894 active_state->after_authentication = 1;
1898 packet_get_input(void)
1900 return (void *)&active_state->input;
1904 packet_get_output(void)
1906 return (void *)&active_state->output;
1910 packet_get_newkeys(int mode)
1912 return (void *)active_state->newkeys[mode];
1916 * Save the state for the real connection, and use a separate state when
1917 * resuming a suspended connection.
1920 packet_backup_state(void)
1922 struct session_state *tmp;
1924 close(active_state->connection_in);
1925 active_state->connection_in = -1;
1926 close(active_state->connection_out);
1927 active_state->connection_out = -1;
1931 tmp = alloc_session_state();
1932 backup_state = active_state;
1937 * Swap in the old state when resuming a connecion.
1940 packet_restore_state(void)
1942 struct session_state *tmp;
1947 backup_state = active_state;
1949 active_state->connection_in = backup_state->connection_in;
1950 backup_state->connection_in = -1;
1951 active_state->connection_out = backup_state->connection_out;
1952 backup_state->connection_out = -1;
1953 len = buffer_len(&backup_state->input);
1955 buf = buffer_ptr(&backup_state->input);
1956 buffer_append(&active_state->input, buf, len);
1957 buffer_clear(&backup_state->input);
1958 add_recv_bytes(len);