xref: /freebsd/crypto/openssh/packet.c (revision ddd5b8e9b4d8957fce018c520657cdfa4ecffad3)
1 /* $OpenBSD: packet.c,v 1.181 2013/02/10 23:35:24 djm Exp $ */
2 /* $FreeBSD$ */
3 /*
4  * Author: Tatu Ylonen <ylo@cs.hut.fi>
5  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
6  *                    All rights reserved
7  * This file contains code implementing the packet protocol and communication
8  * with the other side.  This same code is used both on client and server side.
9  *
10  * As far as I am concerned, the code I have written for this software
11  * can be used freely for any purpose.  Any derived versions of this
12  * software must be clearly marked as such, and if the derived work is
13  * incompatible with the protocol description in the RFC file, it must be
14  * called by a name other than "ssh" or "Secure Shell".
15  *
16  *
17  * SSH2 packet format added by Markus Friedl.
18  * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
19  *
20  * Redistribution and use in source and binary forms, with or without
21  * modification, are permitted provided that the following conditions
22  * are met:
23  * 1. Redistributions of source code must retain the above copyright
24  *    notice, this list of conditions and the following disclaimer.
25  * 2. Redistributions in binary form must reproduce the above copyright
26  *    notice, this list of conditions and the following disclaimer in the
27  *    documentation and/or other materials provided with the distribution.
28  *
29  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
30  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
31  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
32  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
33  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
34  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
35  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
36  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
37  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
38  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
39  */
40 
41 #include "includes.h"
42 
43 #include <sys/types.h>
44 #include "openbsd-compat/sys-queue.h"
45 #include <sys/param.h>
46 #include <sys/socket.h>
47 #ifdef HAVE_SYS_TIME_H
48 # include <sys/time.h>
49 #endif
50 
51 #include <netinet/in.h>
52 #include <netinet/ip.h>
53 #include <arpa/inet.h>
54 
55 #include <errno.h>
56 #include <stdarg.h>
57 #include <stdio.h>
58 #include <stdlib.h>
59 #include <string.h>
60 #include <unistd.h>
61 #include <signal.h>
62 
63 #include "xmalloc.h"
64 #include "buffer.h"
65 #include "packet.h"
66 #include "crc32.h"
67 #include "compress.h"
68 #include "deattack.h"
69 #include "channels.h"
70 #include "compat.h"
71 #include "ssh1.h"
72 #include "ssh2.h"
73 #include "cipher.h"
74 #include "key.h"
75 #include "kex.h"
76 #include "mac.h"
77 #include "log.h"
78 #include "canohost.h"
79 #include "misc.h"
80 #include "ssh.h"
81 #include "roaming.h"
82 
83 #ifdef PACKET_DEBUG
84 #define DBG(x) x
85 #else
86 #define DBG(x)
87 #endif
88 
89 #define PACKET_MAX_SIZE (256 * 1024)
90 
91 struct packet_state {
92 	u_int32_t seqnr;
93 	u_int32_t packets;
94 	u_int64_t blocks;
95 	u_int64_t bytes;
96 };
97 
98 struct packet {
99 	TAILQ_ENTRY(packet) next;
100 	u_char type;
101 	Buffer payload;
102 };
103 
104 struct session_state {
105 	/*
106 	 * This variable contains the file descriptors used for
107 	 * communicating with the other side.  connection_in is used for
108 	 * reading; connection_out for writing.  These can be the same
109 	 * descriptor, in which case it is assumed to be a socket.
110 	 */
111 	int connection_in;
112 	int connection_out;
113 
114 	/* Protocol flags for the remote side. */
115 	u_int remote_protocol_flags;
116 
117 	/* Encryption context for receiving data.  Only used for decryption. */
118 	CipherContext receive_context;
119 
120 	/* Encryption context for sending data.  Only used for encryption. */
121 	CipherContext send_context;
122 
123 	/* Buffer for raw input data from the socket. */
124 	Buffer input;
125 
126 	/* Buffer for raw output data going to the socket. */
127 	Buffer output;
128 
129 	/* Buffer for the partial outgoing packet being constructed. */
130 	Buffer outgoing_packet;
131 
132 	/* Buffer for the incoming packet currently being processed. */
133 	Buffer incoming_packet;
134 
135 	/* Scratch buffer for packet compression/decompression. */
136 	Buffer compression_buffer;
137 	int compression_buffer_ready;
138 
139 	/*
140 	 * Flag indicating whether packet compression/decompression is
141 	 * enabled.
142 	 */
143 	int packet_compression;
144 
145 	/* default maximum packet size */
146 	u_int max_packet_size;
147 
148 	/* Flag indicating whether this module has been initialized. */
149 	int initialized;
150 
151 	/* Set to true if the connection is interactive. */
152 	int interactive_mode;
153 
154 	/* Set to true if we are the server side. */
155 	int server_side;
156 
157 	/* Set to true if we are authenticated. */
158 	int after_authentication;
159 
160 	int keep_alive_timeouts;
161 
162 	/* The maximum time that we will wait to send or receive a packet */
163 	int packet_timeout_ms;
164 
165 	/* Session key information for Encryption and MAC */
166 	Newkeys *newkeys[MODE_MAX];
167 	struct packet_state p_read, p_send;
168 
169 	u_int64_t max_blocks_in, max_blocks_out;
170 	u_int32_t rekey_limit;
171 
172 	/* Session key for protocol v1 */
173 	u_char ssh1_key[SSH_SESSION_KEY_LENGTH];
174 	u_int ssh1_keylen;
175 
176 	/* roundup current message to extra_pad bytes */
177 	u_char extra_pad;
178 
179 	/* XXX discard incoming data after MAC error */
180 	u_int packet_discard;
181 	Mac *packet_discard_mac;
182 
183 	/* Used in packet_read_poll2() */
184 	u_int packlen;
185 
186 	/* Used in packet_send2 */
187 	int rekeying;
188 
189 	/* Used in packet_set_interactive */
190 	int set_interactive_called;
191 
192 	/* Used in packet_set_maxsize */
193 	int set_maxsize_called;
194 
195 	TAILQ_HEAD(, packet) outgoing;
196 };
197 
198 static struct session_state *active_state, *backup_state;
199 #ifdef	NONE_CIPHER_ENABLED
200 static int rekey_requested = 0;
201 #endif
202 
203 static struct session_state *
204 alloc_session_state(void)
205 {
206 	struct session_state *s = xcalloc(1, sizeof(*s));
207 
208 	s->connection_in = -1;
209 	s->connection_out = -1;
210 	s->max_packet_size = 32768;
211 	s->packet_timeout_ms = -1;
212 	return s;
213 }
214 
215 /*
216  * Sets the descriptors used for communication.  Disables encryption until
217  * packet_set_encryption_key is called.
218  */
219 void
220 packet_set_connection(int fd_in, int fd_out)
221 {
222 	Cipher *none = cipher_by_name("none");
223 
224 	if (none == NULL)
225 		fatal("packet_set_connection: cannot load cipher 'none'");
226 	if (active_state == NULL)
227 		active_state = alloc_session_state();
228 	active_state->connection_in = fd_in;
229 	active_state->connection_out = fd_out;
230 	cipher_init(&active_state->send_context, none, (const u_char *)"",
231 	    0, NULL, 0, CIPHER_ENCRYPT);
232 	cipher_init(&active_state->receive_context, none, (const u_char *)"",
233 	    0, NULL, 0, CIPHER_DECRYPT);
234 	active_state->newkeys[MODE_IN] = active_state->newkeys[MODE_OUT] = NULL;
235 	if (!active_state->initialized) {
236 		active_state->initialized = 1;
237 		buffer_init(&active_state->input);
238 		buffer_init(&active_state->output);
239 		buffer_init(&active_state->outgoing_packet);
240 		buffer_init(&active_state->incoming_packet);
241 		TAILQ_INIT(&active_state->outgoing);
242 		active_state->p_send.packets = active_state->p_read.packets = 0;
243 	}
244 }
245 
246 void
247 packet_set_timeout(int timeout, int count)
248 {
249 	if (timeout <= 0 || count <= 0) {
250 		active_state->packet_timeout_ms = -1;
251 		return;
252 	}
253 	if ((INT_MAX / 1000) / count < timeout)
254 		active_state->packet_timeout_ms = INT_MAX;
255 	else
256 		active_state->packet_timeout_ms = timeout * count * 1000;
257 }
258 
259 static void
260 packet_stop_discard(void)
261 {
262 	if (active_state->packet_discard_mac) {
263 		char buf[1024];
264 
265 		memset(buf, 'a', sizeof(buf));
266 		while (buffer_len(&active_state->incoming_packet) <
267 		    PACKET_MAX_SIZE)
268 			buffer_append(&active_state->incoming_packet, buf,
269 			    sizeof(buf));
270 		(void) mac_compute(active_state->packet_discard_mac,
271 		    active_state->p_read.seqnr,
272 		    buffer_ptr(&active_state->incoming_packet),
273 		    PACKET_MAX_SIZE);
274 	}
275 	logit("Finished discarding for %.200s", get_remote_ipaddr());
276 	cleanup_exit(255);
277 }
278 
279 static void
280 packet_start_discard(Enc *enc, Mac *mac, u_int packet_length, u_int discard)
281 {
282 	if (enc == NULL || !cipher_is_cbc(enc->cipher) || (mac && mac->etm))
283 		packet_disconnect("Packet corrupt");
284 	if (packet_length != PACKET_MAX_SIZE && mac && mac->enabled)
285 		active_state->packet_discard_mac = mac;
286 	if (buffer_len(&active_state->input) >= discard)
287 		packet_stop_discard();
288 	active_state->packet_discard = discard -
289 	    buffer_len(&active_state->input);
290 }
291 
292 /* Returns 1 if remote host is connected via socket, 0 if not. */
293 
294 int
295 packet_connection_is_on_socket(void)
296 {
297 	struct sockaddr_storage from, to;
298 	socklen_t fromlen, tolen;
299 
300 	/* filedescriptors in and out are the same, so it's a socket */
301 	if (active_state->connection_in == active_state->connection_out)
302 		return 1;
303 	fromlen = sizeof(from);
304 	memset(&from, 0, sizeof(from));
305 	if (getpeername(active_state->connection_in, (struct sockaddr *)&from,
306 	    &fromlen) < 0)
307 		return 0;
308 	tolen = sizeof(to);
309 	memset(&to, 0, sizeof(to));
310 	if (getpeername(active_state->connection_out, (struct sockaddr *)&to,
311 	    &tolen) < 0)
312 		return 0;
313 	if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0)
314 		return 0;
315 	if (from.ss_family != AF_INET && from.ss_family != AF_INET6)
316 		return 0;
317 	return 1;
318 }
319 
320 /*
321  * Exports an IV from the CipherContext required to export the key
322  * state back from the unprivileged child to the privileged parent
323  * process.
324  */
325 
326 void
327 packet_get_keyiv(int mode, u_char *iv, u_int len)
328 {
329 	CipherContext *cc;
330 
331 	if (mode == MODE_OUT)
332 		cc = &active_state->send_context;
333 	else
334 		cc = &active_state->receive_context;
335 
336 	cipher_get_keyiv(cc, iv, len);
337 }
338 
339 int
340 packet_get_keycontext(int mode, u_char *dat)
341 {
342 	CipherContext *cc;
343 
344 	if (mode == MODE_OUT)
345 		cc = &active_state->send_context;
346 	else
347 		cc = &active_state->receive_context;
348 
349 	return (cipher_get_keycontext(cc, dat));
350 }
351 
352 void
353 packet_set_keycontext(int mode, u_char *dat)
354 {
355 	CipherContext *cc;
356 
357 	if (mode == MODE_OUT)
358 		cc = &active_state->send_context;
359 	else
360 		cc = &active_state->receive_context;
361 
362 	cipher_set_keycontext(cc, dat);
363 }
364 
365 int
366 packet_get_keyiv_len(int mode)
367 {
368 	CipherContext *cc;
369 
370 	if (mode == MODE_OUT)
371 		cc = &active_state->send_context;
372 	else
373 		cc = &active_state->receive_context;
374 
375 	return (cipher_get_keyiv_len(cc));
376 }
377 
378 void
379 packet_set_iv(int mode, u_char *dat)
380 {
381 	CipherContext *cc;
382 
383 	if (mode == MODE_OUT)
384 		cc = &active_state->send_context;
385 	else
386 		cc = &active_state->receive_context;
387 
388 	cipher_set_keyiv(cc, dat);
389 }
390 
391 int
392 packet_get_ssh1_cipher(void)
393 {
394 	return (cipher_get_number(active_state->receive_context.cipher));
395 }
396 
397 void
398 packet_get_state(int mode, u_int32_t *seqnr, u_int64_t *blocks,
399     u_int32_t *packets, u_int64_t *bytes)
400 {
401 	struct packet_state *state;
402 
403 	state = (mode == MODE_IN) ?
404 	    &active_state->p_read : &active_state->p_send;
405 	if (seqnr)
406 		*seqnr = state->seqnr;
407 	if (blocks)
408 		*blocks = state->blocks;
409 	if (packets)
410 		*packets = state->packets;
411 	if (bytes)
412 		*bytes = state->bytes;
413 }
414 
415 void
416 packet_set_state(int mode, u_int32_t seqnr, u_int64_t blocks, u_int32_t packets,
417     u_int64_t bytes)
418 {
419 	struct packet_state *state;
420 
421 	state = (mode == MODE_IN) ?
422 	    &active_state->p_read : &active_state->p_send;
423 	state->seqnr = seqnr;
424 	state->blocks = blocks;
425 	state->packets = packets;
426 	state->bytes = bytes;
427 }
428 
429 static int
430 packet_connection_af(void)
431 {
432 	struct sockaddr_storage to;
433 	socklen_t tolen = sizeof(to);
434 
435 	memset(&to, 0, sizeof(to));
436 	if (getsockname(active_state->connection_out, (struct sockaddr *)&to,
437 	    &tolen) < 0)
438 		return 0;
439 #ifdef IPV4_IN_IPV6
440 	if (to.ss_family == AF_INET6 &&
441 	    IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)&to)->sin6_addr))
442 		return AF_INET;
443 #endif
444 	return to.ss_family;
445 }
446 
447 /* Sets the connection into non-blocking mode. */
448 
449 void
450 packet_set_nonblocking(void)
451 {
452 	/* Set the socket into non-blocking mode. */
453 	set_nonblock(active_state->connection_in);
454 
455 	if (active_state->connection_out != active_state->connection_in)
456 		set_nonblock(active_state->connection_out);
457 }
458 
459 /* Returns the socket used for reading. */
460 
461 int
462 packet_get_connection_in(void)
463 {
464 	return active_state->connection_in;
465 }
466 
467 /* Returns the descriptor used for writing. */
468 
469 int
470 packet_get_connection_out(void)
471 {
472 	return active_state->connection_out;
473 }
474 
475 /* Closes the connection and clears and frees internal data structures. */
476 
477 void
478 packet_close(void)
479 {
480 	if (!active_state->initialized)
481 		return;
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);
486 	} else {
487 		close(active_state->connection_in);
488 		close(active_state->connection_out);
489 	}
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();
497 	}
498 	cipher_cleanup(&active_state->send_context);
499 	cipher_cleanup(&active_state->receive_context);
500 }
501 
502 /* Sets remote side protocol flags. */
503 
504 void
505 packet_set_protocol_flags(u_int protocol_flags)
506 {
507 	active_state->remote_protocol_flags = protocol_flags;
508 }
509 
510 /* Returns the remote protocol flags set earlier by the above function. */
511 
512 u_int
513 packet_get_protocol_flags(void)
514 {
515 	return active_state->remote_protocol_flags;
516 }
517 
518 /*
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.
521  */
522 
523 static void
524 packet_init_compression(void)
525 {
526 	if (active_state->compression_buffer_ready == 1)
527 		return;
528 	active_state->compression_buffer_ready = 1;
529 	buffer_init(&active_state->compression_buffer);
530 }
531 
532 void
533 packet_start_compression(int level)
534 {
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();
541 }
542 
543 /*
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.
547  */
548 
549 void
550 packet_set_encryption_key(const u_char *key, u_int keylen, int number)
551 {
552 	Cipher *cipher = cipher_by_number(number);
553 
554 	if (cipher == NULL)
555 		fatal("packet_set_encryption_key: unknown cipher number %d", number);
556 	if (keylen < 20)
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,
563 	    0, CIPHER_ENCRYPT);
564 	cipher_init(&active_state->receive_context, cipher, key, keylen, NULL,
565 	    0, CIPHER_DECRYPT);
566 }
567 
568 u_int
569 packet_get_encryption_key(u_char *key)
570 {
571 	if (key == NULL)
572 		return (active_state->ssh1_keylen);
573 	memcpy(key, active_state->ssh1_key, active_state->ssh1_keylen);
574 	return (active_state->ssh1_keylen);
575 }
576 
577 /* Start constructing a packet to send. */
578 void
579 packet_start(u_char type)
580 {
581 	u_char buf[9];
582 	int len;
583 
584 	DBG(debug("packet_start[%d]", type));
585 	len = compat20 ? 6 : 9;
586 	memset(buf, 0, len - 1);
587 	buf[len - 1] = type;
588 	buffer_clear(&active_state->outgoing_packet);
589 	buffer_append(&active_state->outgoing_packet, buf, len);
590 }
591 
592 /* Append payload. */
593 void
594 packet_put_char(int value)
595 {
596 	char ch = value;
597 
598 	buffer_append(&active_state->outgoing_packet, &ch, 1);
599 }
600 
601 void
602 packet_put_int(u_int value)
603 {
604 	buffer_put_int(&active_state->outgoing_packet, value);
605 }
606 
607 void
608 packet_put_int64(u_int64_t value)
609 {
610 	buffer_put_int64(&active_state->outgoing_packet, value);
611 }
612 
613 void
614 packet_put_string(const void *buf, u_int len)
615 {
616 	buffer_put_string(&active_state->outgoing_packet, buf, len);
617 }
618 
619 void
620 packet_put_cstring(const char *str)
621 {
622 	buffer_put_cstring(&active_state->outgoing_packet, str);
623 }
624 
625 void
626 packet_put_raw(const void *buf, u_int len)
627 {
628 	buffer_append(&active_state->outgoing_packet, buf, len);
629 }
630 
631 void
632 packet_put_bignum(BIGNUM * value)
633 {
634 	buffer_put_bignum(&active_state->outgoing_packet, value);
635 }
636 
637 void
638 packet_put_bignum2(BIGNUM * value)
639 {
640 	buffer_put_bignum2(&active_state->outgoing_packet, value);
641 }
642 
643 #ifdef OPENSSL_HAS_ECC
644 void
645 packet_put_ecpoint(const EC_GROUP *curve, const EC_POINT *point)
646 {
647 	buffer_put_ecpoint(&active_state->outgoing_packet, curve, point);
648 }
649 #endif
650 
651 /*
652  * Finalizes and sends the packet.  If the encryption key has been set,
653  * encrypts the packet before sending.
654  */
655 
656 static void
657 packet_send1(void)
658 {
659 	u_char buf[8], *cp;
660 	int i, padding, len;
661 	u_int checksum;
662 	u_int32_t rnd = 0;
663 
664 	/*
665 	 * If using packet compression, compress the payload of the outgoing
666 	 * packet.
667 	 */
668 	if (active_state->packet_compression) {
669 		buffer_clear(&active_state->compression_buffer);
670 		/* Skip padding. */
671 		buffer_consume(&active_state->outgoing_packet, 8);
672 		/* padding */
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));
681 	}
682 	/* Compute packet length without padding (add checksum, remove padding). */
683 	len = buffer_len(&active_state->outgoing_packet) + 4 - 8;
684 
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++) {
690 			if (i % 4 == 0)
691 				rnd = arc4random();
692 			cp[7 - i] = rnd & 0xff;
693 			rnd >>= 8;
694 		}
695 	}
696 	buffer_consume(&active_state->outgoing_packet, 8 - padding);
697 
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);
703 
704 #ifdef PACKET_DEBUG
705 	fprintf(stderr, "packet_send plain: ");
706 	buffer_dump(&active_state->outgoing_packet);
707 #endif
708 
709 	/* Append to output. */
710 	put_u32(buf, len);
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), 0, 0);
717 
718 #ifdef PACKET_DEBUG
719 	fprintf(stderr, "encrypted: ");
720 	buffer_dump(&active_state->output);
721 #endif
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);
726 
727 	/*
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
730 	 * called.
731 	 */
732 }
733 
734 void
735 set_newkeys(int mode)
736 {
737 	Enc *enc;
738 	Mac *mac;
739 	Comp *comp;
740 	CipherContext *cc;
741 	u_int64_t *max_blocks;
742 	int crypt_type;
743 
744 	debug2("set_newkeys: mode %d", mode);
745 
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;
751 	} else {
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;
756 	}
757 	if (active_state->newkeys[mode] != NULL) {
758 		debug("set_newkeys: rekeying");
759 		cipher_cleanup(cc);
760 		enc  = &active_state->newkeys[mode]->enc;
761 		mac  = &active_state->newkeys[mode]->mac;
762 		comp = &active_state->newkeys[mode]->comp;
763 		mac_clear(mac);
764 		memset(enc->iv,  0, enc->iv_len);
765 		memset(enc->key, 0, enc->key_len);
766 		memset(mac->key, 0, mac->key_len);
767 		xfree(enc->name);
768 		xfree(enc->iv);
769 		xfree(enc->key);
770 		xfree(mac->name);
771 		xfree(mac->key);
772 		xfree(comp->name);
773 		xfree(active_state->newkeys[mode]);
774 	}
775 	active_state->newkeys[mode] = kex_get_newkeys(mode);
776 	if (active_state->newkeys[mode] == NULL)
777 		fatal("newkeys: no keys for mode %d", mode);
778 	enc  = &active_state->newkeys[mode]->enc;
779 	mac  = &active_state->newkeys[mode]->mac;
780 	comp = &active_state->newkeys[mode]->comp;
781 	if (cipher_authlen(enc->cipher) == 0 && mac_init(mac) == 0)
782 		mac->enabled = 1;
783 	DBG(debug("cipher_init_context: %d", mode));
784 	cipher_init(cc, enc->cipher, enc->key, enc->key_len,
785 	    enc->iv, enc->iv_len, crypt_type);
786 	/* Deleting the keys does not gain extra security */
787 	/* memset(enc->iv,  0, enc->block_size);
788 	   memset(enc->key, 0, enc->key_len);
789 	   memset(mac->key, 0, mac->key_len); */
790 	if ((comp->type == COMP_ZLIB ||
791 	    (comp->type == COMP_DELAYED &&
792 	     active_state->after_authentication)) && comp->enabled == 0) {
793 		packet_init_compression();
794 		if (mode == MODE_OUT)
795 			buffer_compress_init_send(6);
796 		else
797 			buffer_compress_init_recv();
798 		comp->enabled = 1;
799 	}
800 	/*
801 	 * The 2^(blocksize*2) limit is too expensive for 3DES,
802 	 * blowfish, etc, so enforce a 1GB limit for small blocksizes.
803 	 */
804 	if (enc->block_size >= 16)
805 		*max_blocks = (u_int64_t)1 << (enc->block_size*2);
806 	else
807 		*max_blocks = ((u_int64_t)1 << 30) / enc->block_size;
808 	if (active_state->rekey_limit)
809 		*max_blocks = MIN(*max_blocks,
810 		    active_state->rekey_limit / enc->block_size);
811 }
812 
813 /*
814  * Delayed compression for SSH2 is enabled after authentication:
815  * This happens on the server side after a SSH2_MSG_USERAUTH_SUCCESS is sent,
816  * and on the client side after a SSH2_MSG_USERAUTH_SUCCESS is received.
817  */
818 static void
819 packet_enable_delayed_compress(void)
820 {
821 	Comp *comp = NULL;
822 	int mode;
823 
824 	/*
825 	 * Remember that we are past the authentication step, so rekeying
826 	 * with COMP_DELAYED will turn on compression immediately.
827 	 */
828 	active_state->after_authentication = 1;
829 	for (mode = 0; mode < MODE_MAX; mode++) {
830 		/* protocol error: USERAUTH_SUCCESS received before NEWKEYS */
831 		if (active_state->newkeys[mode] == NULL)
832 			continue;
833 		comp = &active_state->newkeys[mode]->comp;
834 		if (comp && !comp->enabled && comp->type == COMP_DELAYED) {
835 			packet_init_compression();
836 			if (mode == MODE_OUT)
837 				buffer_compress_init_send(6);
838 			else
839 				buffer_compress_init_recv();
840 			comp->enabled = 1;
841 		}
842 	}
843 }
844 
845 /*
846  * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue)
847  */
848 static void
849 packet_send2_wrapped(void)
850 {
851 	u_char type, *cp, *macbuf = NULL;
852 	u_char padlen, pad = 0;
853 	u_int i, len, authlen = 0, aadlen = 0;
854 	u_int32_t rnd = 0;
855 	Enc *enc   = NULL;
856 	Mac *mac   = NULL;
857 	Comp *comp = NULL;
858 	int block_size;
859 
860 	if (active_state->newkeys[MODE_OUT] != NULL) {
861 		enc  = &active_state->newkeys[MODE_OUT]->enc;
862 		mac  = &active_state->newkeys[MODE_OUT]->mac;
863 		comp = &active_state->newkeys[MODE_OUT]->comp;
864 		/* disable mac for authenticated encryption */
865 		if ((authlen = cipher_authlen(enc->cipher)) != 0)
866 			mac = NULL;
867 	}
868 	block_size = enc ? enc->block_size : 8;
869 	aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0;
870 
871 	cp = buffer_ptr(&active_state->outgoing_packet);
872 	type = cp[5];
873 
874 #ifdef PACKET_DEBUG
875 	fprintf(stderr, "plain:     ");
876 	buffer_dump(&active_state->outgoing_packet);
877 #endif
878 
879 	if (comp && comp->enabled) {
880 		len = buffer_len(&active_state->outgoing_packet);
881 		/* skip header, compress only payload */
882 		buffer_consume(&active_state->outgoing_packet, 5);
883 		buffer_clear(&active_state->compression_buffer);
884 		buffer_compress(&active_state->outgoing_packet,
885 		    &active_state->compression_buffer);
886 		buffer_clear(&active_state->outgoing_packet);
887 		buffer_append(&active_state->outgoing_packet, "\0\0\0\0\0", 5);
888 		buffer_append(&active_state->outgoing_packet,
889 		    buffer_ptr(&active_state->compression_buffer),
890 		    buffer_len(&active_state->compression_buffer));
891 		DBG(debug("compression: raw %d compressed %d", len,
892 		    buffer_len(&active_state->outgoing_packet)));
893 	}
894 
895 	/* sizeof (packet_len + pad_len + payload) */
896 	len = buffer_len(&active_state->outgoing_packet);
897 
898 	/*
899 	 * calc size of padding, alloc space, get random data,
900 	 * minimum padding is 4 bytes
901 	 */
902 	len -= aadlen; /* packet length is not encrypted for EtM modes */
903 	padlen = block_size - (len % block_size);
904 	if (padlen < 4)
905 		padlen += block_size;
906 	if (active_state->extra_pad) {
907 		/* will wrap if extra_pad+padlen > 255 */
908 		active_state->extra_pad =
909 		    roundup(active_state->extra_pad, block_size);
910 		pad = active_state->extra_pad -
911 		    ((len + padlen) % active_state->extra_pad);
912 		debug3("packet_send2: adding %d (len %d padlen %d extra_pad %d)",
913 		    pad, len, padlen, active_state->extra_pad);
914 		padlen += pad;
915 		active_state->extra_pad = 0;
916 	}
917 	cp = buffer_append_space(&active_state->outgoing_packet, padlen);
918 	if (enc && !active_state->send_context.plaintext) {
919 		/* random padding */
920 		for (i = 0; i < padlen; i++) {
921 			if (i % 4 == 0)
922 				rnd = arc4random();
923 			cp[i] = rnd & 0xff;
924 			rnd >>= 8;
925 		}
926 	} else {
927 		/* clear padding */
928 		memset(cp, 0, padlen);
929 	}
930 	/* sizeof (packet_len + pad_len + payload + padding) */
931 	len = buffer_len(&active_state->outgoing_packet);
932 	cp = buffer_ptr(&active_state->outgoing_packet);
933 	/* packet_length includes payload, padding and padding length field */
934 	put_u32(cp, len - 4);
935 	cp[4] = padlen;
936 	DBG(debug("send: len %d (includes padlen %d, aadlen %d)",
937 	    len, padlen, aadlen));
938 
939 	/* compute MAC over seqnr and packet(length fields, payload, padding) */
940 	if (mac && mac->enabled && !mac->etm) {
941 		macbuf = mac_compute(mac, active_state->p_send.seqnr,
942 		    buffer_ptr(&active_state->outgoing_packet), len);
943 		DBG(debug("done calc MAC out #%d", active_state->p_send.seqnr));
944 	}
945 	/* encrypt packet and append to output buffer. */
946 	cp = buffer_append_space(&active_state->output, len + authlen);
947 	cipher_crypt(&active_state->send_context, cp,
948 	    buffer_ptr(&active_state->outgoing_packet),
949 	    len - aadlen, aadlen, authlen);
950 	/* append unencrypted MAC */
951 	if (mac && mac->enabled) {
952 		if (mac->etm) {
953 			/* EtM: compute mac over aadlen + cipher text */
954 			macbuf = mac_compute(mac,
955 			    active_state->p_send.seqnr, cp, len);
956 			DBG(debug("done calc MAC(EtM) out #%d",
957 			    active_state->p_send.seqnr));
958 		}
959 		buffer_append(&active_state->output, macbuf, mac->mac_len);
960 	}
961 #ifdef PACKET_DEBUG
962 	fprintf(stderr, "encrypted: ");
963 	buffer_dump(&active_state->output);
964 #endif
965 	/* increment sequence number for outgoing packets */
966 	if (++active_state->p_send.seqnr == 0)
967 		logit("outgoing seqnr wraps around");
968 	if (++active_state->p_send.packets == 0)
969 		if (!(datafellows & SSH_BUG_NOREKEY))
970 			fatal("XXX too many packets with same key");
971 	active_state->p_send.blocks += len / block_size;
972 	active_state->p_send.bytes += len;
973 	buffer_clear(&active_state->outgoing_packet);
974 
975 	if (type == SSH2_MSG_NEWKEYS)
976 		set_newkeys(MODE_OUT);
977 	else if (type == SSH2_MSG_USERAUTH_SUCCESS && active_state->server_side)
978 		packet_enable_delayed_compress();
979 }
980 
981 static void
982 packet_send2(void)
983 {
984 	struct packet *p;
985 	u_char type, *cp;
986 
987 	cp = buffer_ptr(&active_state->outgoing_packet);
988 	type = cp[5];
989 
990 	/* during rekeying we can only send key exchange messages */
991 	if (active_state->rekeying) {
992 		if ((type < SSH2_MSG_TRANSPORT_MIN) ||
993 		    (type > SSH2_MSG_TRANSPORT_MAX) ||
994 		    (type == SSH2_MSG_SERVICE_REQUEST) ||
995 		    (type == SSH2_MSG_SERVICE_ACCEPT)) {
996 			debug("enqueue packet: %u", type);
997 			p = xmalloc(sizeof(*p));
998 			p->type = type;
999 			memcpy(&p->payload, &active_state->outgoing_packet,
1000 			    sizeof(Buffer));
1001 			buffer_init(&active_state->outgoing_packet);
1002 			TAILQ_INSERT_TAIL(&active_state->outgoing, p, next);
1003 			return;
1004 		}
1005 	}
1006 
1007 	/* rekeying starts with sending KEXINIT */
1008 	if (type == SSH2_MSG_KEXINIT)
1009 		active_state->rekeying = 1;
1010 
1011 	packet_send2_wrapped();
1012 
1013 	/* after a NEWKEYS message we can send the complete queue */
1014 	if (type == SSH2_MSG_NEWKEYS) {
1015 		active_state->rekeying = 0;
1016 		while ((p = TAILQ_FIRST(&active_state->outgoing))) {
1017 			type = p->type;
1018 			debug("dequeue packet: %u", type);
1019 			buffer_free(&active_state->outgoing_packet);
1020 			memcpy(&active_state->outgoing_packet, &p->payload,
1021 			    sizeof(Buffer));
1022 			TAILQ_REMOVE(&active_state->outgoing, p, next);
1023 			xfree(p);
1024 			packet_send2_wrapped();
1025 		}
1026 	}
1027 }
1028 
1029 void
1030 packet_send(void)
1031 {
1032 	if (compat20)
1033 		packet_send2();
1034 	else
1035 		packet_send1();
1036 	DBG(debug("packet_send done"));
1037 }
1038 
1039 /*
1040  * Waits until a packet has been received, and returns its type.  Note that
1041  * no other data is processed until this returns, so this function should not
1042  * be used during the interactive session.
1043  */
1044 
1045 int
1046 packet_read_seqnr(u_int32_t *seqnr_p)
1047 {
1048 	int type, len, ret, ms_remain, cont;
1049 	fd_set *setp;
1050 	char buf[8192];
1051 	struct timeval timeout, start, *timeoutp = NULL;
1052 
1053 	DBG(debug("packet_read()"));
1054 
1055 	setp = (fd_set *)xcalloc(howmany(active_state->connection_in + 1,
1056 	    NFDBITS), sizeof(fd_mask));
1057 
1058 	/* Since we are blocking, ensure that all written packets have been sent. */
1059 	packet_write_wait();
1060 
1061 	/* Stay in the loop until we have received a complete packet. */
1062 	for (;;) {
1063 		/* Try to read a packet from the buffer. */
1064 		type = packet_read_poll_seqnr(seqnr_p);
1065 		if (!compat20 && (
1066 		    type == SSH_SMSG_SUCCESS
1067 		    || type == SSH_SMSG_FAILURE
1068 		    || type == SSH_CMSG_EOF
1069 		    || type == SSH_CMSG_EXIT_CONFIRMATION))
1070 			packet_check_eom();
1071 		/* If we got a packet, return it. */
1072 		if (type != SSH_MSG_NONE) {
1073 			xfree(setp);
1074 			return type;
1075 		}
1076 		/*
1077 		 * Otherwise, wait for some data to arrive, add it to the
1078 		 * buffer, and try again.
1079 		 */
1080 		memset(setp, 0, howmany(active_state->connection_in + 1,
1081 		    NFDBITS) * sizeof(fd_mask));
1082 		FD_SET(active_state->connection_in, setp);
1083 
1084 		if (active_state->packet_timeout_ms > 0) {
1085 			ms_remain = active_state->packet_timeout_ms;
1086 			timeoutp = &timeout;
1087 		}
1088 		/* Wait for some data to arrive. */
1089 		for (;;) {
1090 			if (active_state->packet_timeout_ms != -1) {
1091 				ms_to_timeval(&timeout, ms_remain);
1092 				gettimeofday(&start, NULL);
1093 			}
1094 			if ((ret = select(active_state->connection_in + 1, setp,
1095 			    NULL, NULL, timeoutp)) >= 0)
1096 				break;
1097 			if (errno != EAGAIN && errno != EINTR &&
1098 			    errno != EWOULDBLOCK)
1099 				break;
1100 			if (active_state->packet_timeout_ms == -1)
1101 				continue;
1102 			ms_subtract_diff(&start, &ms_remain);
1103 			if (ms_remain <= 0) {
1104 				ret = 0;
1105 				break;
1106 			}
1107 		}
1108 		if (ret == 0) {
1109 			logit("Connection to %.200s timed out while "
1110 			    "waiting to read", get_remote_ipaddr());
1111 			cleanup_exit(255);
1112 		}
1113 		/* Read data from the socket. */
1114 		do {
1115 			cont = 0;
1116 			len = roaming_read(active_state->connection_in, buf,
1117 			    sizeof(buf), &cont);
1118 		} while (len == 0 && cont);
1119 		if (len == 0) {
1120 			logit("Connection closed by %.200s", get_remote_ipaddr());
1121 			cleanup_exit(255);
1122 		}
1123 		if (len < 0)
1124 			fatal("Read from socket failed: %.100s", strerror(errno));
1125 		/* Append it to the buffer. */
1126 		packet_process_incoming(buf, len);
1127 	}
1128 	/* NOTREACHED */
1129 }
1130 
1131 int
1132 packet_read(void)
1133 {
1134 	return packet_read_seqnr(NULL);
1135 }
1136 
1137 /*
1138  * Waits until a packet has been received, verifies that its type matches
1139  * that given, and gives a fatal error and exits if there is a mismatch.
1140  */
1141 
1142 void
1143 packet_read_expect(int expected_type)
1144 {
1145 	int type;
1146 
1147 	type = packet_read();
1148 	if (type != expected_type)
1149 		packet_disconnect("Protocol error: expected packet type %d, got %d",
1150 		    expected_type, type);
1151 }
1152 
1153 /* Checks if a full packet is available in the data received so far via
1154  * packet_process_incoming.  If so, reads the packet; otherwise returns
1155  * SSH_MSG_NONE.  This does not wait for data from the connection.
1156  *
1157  * SSH_MSG_DISCONNECT is handled specially here.  Also,
1158  * SSH_MSG_IGNORE messages are skipped by this function and are never returned
1159  * to higher levels.
1160  */
1161 
1162 static int
1163 packet_read_poll1(void)
1164 {
1165 	u_int len, padded_len;
1166 	u_char *cp, type;
1167 	u_int checksum, stored_checksum;
1168 
1169 	/* Check if input size is less than minimum packet size. */
1170 	if (buffer_len(&active_state->input) < 4 + 8)
1171 		return SSH_MSG_NONE;
1172 	/* Get length of incoming packet. */
1173 	cp = buffer_ptr(&active_state->input);
1174 	len = get_u32(cp);
1175 	if (len < 1 + 2 + 2 || len > 256 * 1024)
1176 		packet_disconnect("Bad packet length %u.", len);
1177 	padded_len = (len + 8) & ~7;
1178 
1179 	/* Check if the packet has been entirely received. */
1180 	if (buffer_len(&active_state->input) < 4 + padded_len)
1181 		return SSH_MSG_NONE;
1182 
1183 	/* The entire packet is in buffer. */
1184 
1185 	/* Consume packet length. */
1186 	buffer_consume(&active_state->input, 4);
1187 
1188 	/*
1189 	 * Cryptographic attack detector for ssh
1190 	 * (C)1998 CORE-SDI, Buenos Aires Argentina
1191 	 * Ariel Futoransky(futo@core-sdi.com)
1192 	 */
1193 	if (!active_state->receive_context.plaintext) {
1194 		switch (detect_attack(buffer_ptr(&active_state->input),
1195 		    padded_len)) {
1196 		case DEATTACK_DETECTED:
1197 			packet_disconnect("crc32 compensation attack: "
1198 			    "network attack detected");
1199 		case DEATTACK_DOS_DETECTED:
1200 			packet_disconnect("deattack denial of "
1201 			    "service detected");
1202 		}
1203 	}
1204 
1205 	/* Decrypt data to incoming_packet. */
1206 	buffer_clear(&active_state->incoming_packet);
1207 	cp = buffer_append_space(&active_state->incoming_packet, padded_len);
1208 	cipher_crypt(&active_state->receive_context, cp,
1209 	    buffer_ptr(&active_state->input), padded_len, 0, 0);
1210 
1211 	buffer_consume(&active_state->input, padded_len);
1212 
1213 #ifdef PACKET_DEBUG
1214 	fprintf(stderr, "read_poll plain: ");
1215 	buffer_dump(&active_state->incoming_packet);
1216 #endif
1217 
1218 	/* Compute packet checksum. */
1219 	checksum = ssh_crc32(buffer_ptr(&active_state->incoming_packet),
1220 	    buffer_len(&active_state->incoming_packet) - 4);
1221 
1222 	/* Skip padding. */
1223 	buffer_consume(&active_state->incoming_packet, 8 - len % 8);
1224 
1225 	/* Test check bytes. */
1226 	if (len != buffer_len(&active_state->incoming_packet))
1227 		packet_disconnect("packet_read_poll1: len %d != buffer_len %d.",
1228 		    len, buffer_len(&active_state->incoming_packet));
1229 
1230 	cp = (u_char *)buffer_ptr(&active_state->incoming_packet) + len - 4;
1231 	stored_checksum = get_u32(cp);
1232 	if (checksum != stored_checksum)
1233 		packet_disconnect("Corrupted check bytes on input.");
1234 	buffer_consume_end(&active_state->incoming_packet, 4);
1235 
1236 	if (active_state->packet_compression) {
1237 		buffer_clear(&active_state->compression_buffer);
1238 		buffer_uncompress(&active_state->incoming_packet,
1239 		    &active_state->compression_buffer);
1240 		buffer_clear(&active_state->incoming_packet);
1241 		buffer_append(&active_state->incoming_packet,
1242 		    buffer_ptr(&active_state->compression_buffer),
1243 		    buffer_len(&active_state->compression_buffer));
1244 	}
1245 	active_state->p_read.packets++;
1246 	active_state->p_read.bytes += padded_len + 4;
1247 	type = buffer_get_char(&active_state->incoming_packet);
1248 	if (type < SSH_MSG_MIN || type > SSH_MSG_MAX)
1249 		packet_disconnect("Invalid ssh1 packet type: %d", type);
1250 	return type;
1251 }
1252 
1253 static int
1254 packet_read_poll2(u_int32_t *seqnr_p)
1255 {
1256 	u_int padlen, need;
1257 	u_char *macbuf = NULL, *cp, type;
1258 	u_int maclen, authlen = 0, aadlen = 0, block_size;
1259 	Enc *enc   = NULL;
1260 	Mac *mac   = NULL;
1261 	Comp *comp = NULL;
1262 
1263 	if (active_state->packet_discard)
1264 		return SSH_MSG_NONE;
1265 
1266 	if (active_state->newkeys[MODE_IN] != NULL) {
1267 		enc  = &active_state->newkeys[MODE_IN]->enc;
1268 		mac  = &active_state->newkeys[MODE_IN]->mac;
1269 		comp = &active_state->newkeys[MODE_IN]->comp;
1270 		/* disable mac for authenticated encryption */
1271 		if ((authlen = cipher_authlen(enc->cipher)) != 0)
1272 			mac = NULL;
1273 	}
1274 	maclen = mac && mac->enabled ? mac->mac_len : 0;
1275 	block_size = enc ? enc->block_size : 8;
1276 	aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0;
1277 
1278 	if (aadlen && active_state->packlen == 0) {
1279 		if (buffer_len(&active_state->input) < 4)
1280 			return SSH_MSG_NONE;
1281 		cp = buffer_ptr(&active_state->input);
1282 		active_state->packlen = get_u32(cp);
1283 		if (active_state->packlen < 1 + 4 ||
1284 		    active_state->packlen > PACKET_MAX_SIZE) {
1285 #ifdef PACKET_DEBUG
1286 			buffer_dump(&active_state->input);
1287 #endif
1288 			logit("Bad packet length %u.", active_state->packlen);
1289 			packet_disconnect("Packet corrupt");
1290 		}
1291 		buffer_clear(&active_state->incoming_packet);
1292 	} else if (active_state->packlen == 0) {
1293 		/*
1294 		 * check if input size is less than the cipher block size,
1295 		 * decrypt first block and extract length of incoming packet
1296 		 */
1297 		if (buffer_len(&active_state->input) < block_size)
1298 			return SSH_MSG_NONE;
1299 		buffer_clear(&active_state->incoming_packet);
1300 		cp = buffer_append_space(&active_state->incoming_packet,
1301 		    block_size);
1302 		cipher_crypt(&active_state->receive_context, cp,
1303 		    buffer_ptr(&active_state->input), block_size, 0, 0);
1304 		cp = buffer_ptr(&active_state->incoming_packet);
1305 
1306 		active_state->packlen = get_u32(cp);
1307 		if (active_state->packlen < 1 + 4 ||
1308 		    active_state->packlen > PACKET_MAX_SIZE) {
1309 #ifdef PACKET_DEBUG
1310 			buffer_dump(&active_state->incoming_packet);
1311 #endif
1312 			logit("Bad packet length %u.", active_state->packlen);
1313 			packet_start_discard(enc, mac, active_state->packlen,
1314 			    PACKET_MAX_SIZE);
1315 			return SSH_MSG_NONE;
1316 		}
1317 		buffer_consume(&active_state->input, block_size);
1318 	}
1319 	DBG(debug("input: packet len %u", active_state->packlen+4));
1320 	if (aadlen) {
1321 		/* only the payload is encrypted */
1322 		need = active_state->packlen;
1323 	} else {
1324 		/*
1325 		 * the payload size and the payload are encrypted, but we
1326 		 * have a partial packet of block_size bytes
1327 		 */
1328 		need = 4 + active_state->packlen - block_size;
1329 	}
1330 	DBG(debug("partial packet: block %d, need %d, maclen %d, authlen %d,"
1331 	    " aadlen %d", block_size, need, maclen, authlen, aadlen));
1332 	if (need % block_size != 0) {
1333 		logit("padding error: need %d block %d mod %d",
1334 		    need, block_size, need % block_size);
1335 		packet_start_discard(enc, mac, active_state->packlen,
1336 		    PACKET_MAX_SIZE - block_size);
1337 		return SSH_MSG_NONE;
1338 	}
1339 	/*
1340 	 * check if the entire packet has been received and
1341 	 * decrypt into incoming_packet:
1342 	 * 'aadlen' bytes are unencrypted, but authenticated.
1343 	 * 'need' bytes are encrypted, followed by either
1344 	 * 'authlen' bytes of authentication tag or
1345 	 * 'maclen' bytes of message authentication code.
1346 	 */
1347 	if (buffer_len(&active_state->input) < aadlen + need + authlen + maclen)
1348 		return SSH_MSG_NONE;
1349 #ifdef PACKET_DEBUG
1350 	fprintf(stderr, "read_poll enc/full: ");
1351 	buffer_dump(&active_state->input);
1352 #endif
1353 	/* EtM: compute mac over encrypted input */
1354 	if (mac && mac->enabled && mac->etm)
1355 		macbuf = mac_compute(mac, active_state->p_read.seqnr,
1356 		    buffer_ptr(&active_state->input), aadlen + need);
1357 	cp = buffer_append_space(&active_state->incoming_packet, aadlen + need);
1358 	cipher_crypt(&active_state->receive_context, cp,
1359 	    buffer_ptr(&active_state->input), need, aadlen, authlen);
1360 	buffer_consume(&active_state->input, aadlen + need + authlen);
1361 	/*
1362 	 * compute MAC over seqnr and packet,
1363 	 * increment sequence number for incoming packet
1364 	 */
1365 	if (mac && mac->enabled) {
1366 		if (!mac->etm)
1367 			macbuf = mac_compute(mac, active_state->p_read.seqnr,
1368 			    buffer_ptr(&active_state->incoming_packet),
1369 			    buffer_len(&active_state->incoming_packet));
1370 		if (timingsafe_bcmp(macbuf, buffer_ptr(&active_state->input),
1371 		    mac->mac_len) != 0) {
1372 			logit("Corrupted MAC on input.");
1373 			if (need > PACKET_MAX_SIZE)
1374 				fatal("internal error need %d", need);
1375 			packet_start_discard(enc, mac, active_state->packlen,
1376 			    PACKET_MAX_SIZE - need);
1377 			return SSH_MSG_NONE;
1378 		}
1379 
1380 		DBG(debug("MAC #%d ok", active_state->p_read.seqnr));
1381 		buffer_consume(&active_state->input, mac->mac_len);
1382 	}
1383 	/* XXX now it's safe to use fatal/packet_disconnect */
1384 	if (seqnr_p != NULL)
1385 		*seqnr_p = active_state->p_read.seqnr;
1386 	if (++active_state->p_read.seqnr == 0)
1387 		logit("incoming seqnr wraps around");
1388 	if (++active_state->p_read.packets == 0)
1389 		if (!(datafellows & SSH_BUG_NOREKEY))
1390 			fatal("XXX too many packets with same key");
1391 	active_state->p_read.blocks += (active_state->packlen + 4) / block_size;
1392 	active_state->p_read.bytes += active_state->packlen + 4;
1393 
1394 	/* get padlen */
1395 	cp = buffer_ptr(&active_state->incoming_packet);
1396 	padlen = cp[4];
1397 	DBG(debug("input: padlen %d", padlen));
1398 	if (padlen < 4)
1399 		packet_disconnect("Corrupted padlen %d on input.", padlen);
1400 
1401 	/* skip packet size + padlen, discard padding */
1402 	buffer_consume(&active_state->incoming_packet, 4 + 1);
1403 	buffer_consume_end(&active_state->incoming_packet, padlen);
1404 
1405 	DBG(debug("input: len before de-compress %d",
1406 	    buffer_len(&active_state->incoming_packet)));
1407 	if (comp && comp->enabled) {
1408 		buffer_clear(&active_state->compression_buffer);
1409 		buffer_uncompress(&active_state->incoming_packet,
1410 		    &active_state->compression_buffer);
1411 		buffer_clear(&active_state->incoming_packet);
1412 		buffer_append(&active_state->incoming_packet,
1413 		    buffer_ptr(&active_state->compression_buffer),
1414 		    buffer_len(&active_state->compression_buffer));
1415 		DBG(debug("input: len after de-compress %d",
1416 		    buffer_len(&active_state->incoming_packet)));
1417 	}
1418 	/*
1419 	 * get packet type, implies consume.
1420 	 * return length of payload (without type field)
1421 	 */
1422 	type = buffer_get_char(&active_state->incoming_packet);
1423 	if (type < SSH2_MSG_MIN || type >= SSH2_MSG_LOCAL_MIN)
1424 		packet_disconnect("Invalid ssh2 packet type: %d", type);
1425 	if (type == SSH2_MSG_NEWKEYS)
1426 		set_newkeys(MODE_IN);
1427 	else if (type == SSH2_MSG_USERAUTH_SUCCESS &&
1428 	    !active_state->server_side)
1429 		packet_enable_delayed_compress();
1430 #ifdef PACKET_DEBUG
1431 	fprintf(stderr, "read/plain[%d]:\r\n", type);
1432 	buffer_dump(&active_state->incoming_packet);
1433 #endif
1434 	/* reset for next packet */
1435 	active_state->packlen = 0;
1436 	return type;
1437 }
1438 
1439 int
1440 packet_read_poll_seqnr(u_int32_t *seqnr_p)
1441 {
1442 	u_int reason, seqnr;
1443 	u_char type;
1444 	char *msg;
1445 
1446 	for (;;) {
1447 		if (compat20) {
1448 			type = packet_read_poll2(seqnr_p);
1449 			if (type) {
1450 				active_state->keep_alive_timeouts = 0;
1451 				DBG(debug("received packet type %d", type));
1452 			}
1453 			switch (type) {
1454 			case SSH2_MSG_IGNORE:
1455 				debug3("Received SSH2_MSG_IGNORE");
1456 				break;
1457 			case SSH2_MSG_DEBUG:
1458 				packet_get_char();
1459 				msg = packet_get_string(NULL);
1460 				debug("Remote: %.900s", msg);
1461 				xfree(msg);
1462 				msg = packet_get_string(NULL);
1463 				xfree(msg);
1464 				break;
1465 			case SSH2_MSG_DISCONNECT:
1466 				reason = packet_get_int();
1467 				msg = packet_get_string(NULL);
1468 				error("Received disconnect from %s: %u: %.400s",
1469 				    get_remote_ipaddr(), reason, msg);
1470 				xfree(msg);
1471 				cleanup_exit(255);
1472 				break;
1473 			case SSH2_MSG_UNIMPLEMENTED:
1474 				seqnr = packet_get_int();
1475 				debug("Received SSH2_MSG_UNIMPLEMENTED for %u",
1476 				    seqnr);
1477 				break;
1478 			default:
1479 				return type;
1480 			}
1481 		} else {
1482 			type = packet_read_poll1();
1483 			switch (type) {
1484 			case SSH_MSG_IGNORE:
1485 				break;
1486 			case SSH_MSG_DEBUG:
1487 				msg = packet_get_string(NULL);
1488 				debug("Remote: %.900s", msg);
1489 				xfree(msg);
1490 				break;
1491 			case SSH_MSG_DISCONNECT:
1492 				msg = packet_get_string(NULL);
1493 				error("Received disconnect from %s: %.400s",
1494 				    get_remote_ipaddr(), msg);
1495 				cleanup_exit(255);
1496 				break;
1497 			default:
1498 				if (type)
1499 					DBG(debug("received packet type %d", type));
1500 				return type;
1501 			}
1502 		}
1503 	}
1504 }
1505 
1506 /*
1507  * Buffers the given amount of input characters.  This is intended to be used
1508  * together with packet_read_poll.
1509  */
1510 
1511 void
1512 packet_process_incoming(const char *buf, u_int len)
1513 {
1514 	if (active_state->packet_discard) {
1515 		active_state->keep_alive_timeouts = 0; /* ?? */
1516 		if (len >= active_state->packet_discard)
1517 			packet_stop_discard();
1518 		active_state->packet_discard -= len;
1519 		return;
1520 	}
1521 	buffer_append(&active_state->input, buf, len);
1522 }
1523 
1524 /* Returns a character from the packet. */
1525 
1526 u_int
1527 packet_get_char(void)
1528 {
1529 	char ch;
1530 
1531 	buffer_get(&active_state->incoming_packet, &ch, 1);
1532 	return (u_char) ch;
1533 }
1534 
1535 /* Returns an integer from the packet data. */
1536 
1537 u_int
1538 packet_get_int(void)
1539 {
1540 	return buffer_get_int(&active_state->incoming_packet);
1541 }
1542 
1543 /* Returns an 64 bit integer from the packet data. */
1544 
1545 u_int64_t
1546 packet_get_int64(void)
1547 {
1548 	return buffer_get_int64(&active_state->incoming_packet);
1549 }
1550 
1551 /*
1552  * Returns an arbitrary precision integer from the packet data.  The integer
1553  * must have been initialized before this call.
1554  */
1555 
1556 void
1557 packet_get_bignum(BIGNUM * value)
1558 {
1559 	buffer_get_bignum(&active_state->incoming_packet, value);
1560 }
1561 
1562 void
1563 packet_get_bignum2(BIGNUM * value)
1564 {
1565 	buffer_get_bignum2(&active_state->incoming_packet, value);
1566 }
1567 
1568 #ifdef OPENSSL_HAS_ECC
1569 void
1570 packet_get_ecpoint(const EC_GROUP *curve, EC_POINT *point)
1571 {
1572 	buffer_get_ecpoint(&active_state->incoming_packet, curve, point);
1573 }
1574 #endif
1575 
1576 void *
1577 packet_get_raw(u_int *length_ptr)
1578 {
1579 	u_int bytes = buffer_len(&active_state->incoming_packet);
1580 
1581 	if (length_ptr != NULL)
1582 		*length_ptr = bytes;
1583 	return buffer_ptr(&active_state->incoming_packet);
1584 }
1585 
1586 int
1587 packet_remaining(void)
1588 {
1589 	return buffer_len(&active_state->incoming_packet);
1590 }
1591 
1592 /*
1593  * Returns a string from the packet data.  The string is allocated using
1594  * xmalloc; it is the responsibility of the calling program to free it when
1595  * no longer needed.  The length_ptr argument may be NULL, or point to an
1596  * integer into which the length of the string is stored.
1597  */
1598 
1599 void *
1600 packet_get_string(u_int *length_ptr)
1601 {
1602 	return buffer_get_string(&active_state->incoming_packet, length_ptr);
1603 }
1604 
1605 void *
1606 packet_get_string_ptr(u_int *length_ptr)
1607 {
1608 	return buffer_get_string_ptr(&active_state->incoming_packet, length_ptr);
1609 }
1610 
1611 /* Ensures the returned string has no embedded \0 characters in it. */
1612 char *
1613 packet_get_cstring(u_int *length_ptr)
1614 {
1615 	return buffer_get_cstring(&active_state->incoming_packet, length_ptr);
1616 }
1617 
1618 /*
1619  * Sends a diagnostic message from the server to the client.  This message
1620  * can be sent at any time (but not while constructing another message). The
1621  * message is printed immediately, but only if the client is being executed
1622  * in verbose mode.  These messages are primarily intended to ease debugging
1623  * authentication problems.   The length of the formatted message must not
1624  * exceed 1024 bytes.  This will automatically call packet_write_wait.
1625  */
1626 
1627 void
1628 packet_send_debug(const char *fmt,...)
1629 {
1630 	char buf[1024];
1631 	va_list args;
1632 
1633 	if (compat20 && (datafellows & SSH_BUG_DEBUG))
1634 		return;
1635 
1636 	va_start(args, fmt);
1637 	vsnprintf(buf, sizeof(buf), fmt, args);
1638 	va_end(args);
1639 
1640 	if (compat20) {
1641 		packet_start(SSH2_MSG_DEBUG);
1642 		packet_put_char(0);	/* bool: always display */
1643 		packet_put_cstring(buf);
1644 		packet_put_cstring("");
1645 	} else {
1646 		packet_start(SSH_MSG_DEBUG);
1647 		packet_put_cstring(buf);
1648 	}
1649 	packet_send();
1650 	packet_write_wait();
1651 }
1652 
1653 /*
1654  * Logs the error plus constructs and sends a disconnect packet, closes the
1655  * connection, and exits.  This function never returns. The error message
1656  * should not contain a newline.  The length of the formatted message must
1657  * not exceed 1024 bytes.
1658  */
1659 
1660 void
1661 packet_disconnect(const char *fmt,...)
1662 {
1663 	char buf[1024];
1664 	va_list args;
1665 	static int disconnecting = 0;
1666 
1667 	if (disconnecting)	/* Guard against recursive invocations. */
1668 		fatal("packet_disconnect called recursively.");
1669 	disconnecting = 1;
1670 
1671 	/*
1672 	 * Format the message.  Note that the caller must make sure the
1673 	 * message is of limited size.
1674 	 */
1675 	va_start(args, fmt);
1676 	vsnprintf(buf, sizeof(buf), fmt, args);
1677 	va_end(args);
1678 
1679 	/* Display the error locally */
1680 	logit("Disconnecting: %.100s", buf);
1681 
1682 	/* Send the disconnect message to the other side, and wait for it to get sent. */
1683 	if (compat20) {
1684 		packet_start(SSH2_MSG_DISCONNECT);
1685 		packet_put_int(SSH2_DISCONNECT_PROTOCOL_ERROR);
1686 		packet_put_cstring(buf);
1687 		packet_put_cstring("");
1688 	} else {
1689 		packet_start(SSH_MSG_DISCONNECT);
1690 		packet_put_cstring(buf);
1691 	}
1692 	packet_send();
1693 	packet_write_wait();
1694 
1695 	/* Stop listening for connections. */
1696 	channel_close_all();
1697 
1698 	/* Close the connection. */
1699 	packet_close();
1700 	cleanup_exit(255);
1701 }
1702 
1703 /* Checks if there is any buffered output, and tries to write some of the output. */
1704 
1705 void
1706 packet_write_poll(void)
1707 {
1708 	int len = buffer_len(&active_state->output);
1709 	int cont;
1710 
1711 	if (len > 0) {
1712 		cont = 0;
1713 		len = roaming_write(active_state->connection_out,
1714 		    buffer_ptr(&active_state->output), len, &cont);
1715 		if (len == -1) {
1716 			if (errno == EINTR || errno == EAGAIN ||
1717 			    errno == EWOULDBLOCK)
1718 				return;
1719 			fatal("Write failed: %.100s", strerror(errno));
1720 		}
1721 		if (len == 0 && !cont)
1722 			fatal("Write connection closed");
1723 		buffer_consume(&active_state->output, len);
1724 	}
1725 }
1726 
1727 /*
1728  * Calls packet_write_poll repeatedly until all pending output data has been
1729  * written.
1730  */
1731 
1732 void
1733 packet_write_wait(void)
1734 {
1735 	fd_set *setp;
1736 	int ret, ms_remain;
1737 	struct timeval start, timeout, *timeoutp = NULL;
1738 
1739 	setp = (fd_set *)xcalloc(howmany(active_state->connection_out + 1,
1740 	    NFDBITS), sizeof(fd_mask));
1741 	packet_write_poll();
1742 	while (packet_have_data_to_write()) {
1743 		memset(setp, 0, howmany(active_state->connection_out + 1,
1744 		    NFDBITS) * sizeof(fd_mask));
1745 		FD_SET(active_state->connection_out, setp);
1746 
1747 		if (active_state->packet_timeout_ms > 0) {
1748 			ms_remain = active_state->packet_timeout_ms;
1749 			timeoutp = &timeout;
1750 		}
1751 		for (;;) {
1752 			if (active_state->packet_timeout_ms != -1) {
1753 				ms_to_timeval(&timeout, ms_remain);
1754 				gettimeofday(&start, NULL);
1755 			}
1756 			if ((ret = select(active_state->connection_out + 1,
1757 			    NULL, setp, NULL, timeoutp)) >= 0)
1758 				break;
1759 			if (errno != EAGAIN && errno != EINTR &&
1760 			    errno != EWOULDBLOCK)
1761 				break;
1762 			if (active_state->packet_timeout_ms == -1)
1763 				continue;
1764 			ms_subtract_diff(&start, &ms_remain);
1765 			if (ms_remain <= 0) {
1766 				ret = 0;
1767 				break;
1768 			}
1769 		}
1770 		if (ret == 0) {
1771 			logit("Connection to %.200s timed out while "
1772 			    "waiting to write", get_remote_ipaddr());
1773 			cleanup_exit(255);
1774 		}
1775 		packet_write_poll();
1776 	}
1777 	xfree(setp);
1778 }
1779 
1780 /* Returns true if there is buffered data to write to the connection. */
1781 
1782 int
1783 packet_have_data_to_write(void)
1784 {
1785 	return buffer_len(&active_state->output) != 0;
1786 }
1787 
1788 /* Returns true if there is not too much data to write to the connection. */
1789 
1790 int
1791 packet_not_very_much_data_to_write(void)
1792 {
1793 	if (active_state->interactive_mode)
1794 		return buffer_len(&active_state->output) < 16384;
1795 	else
1796 		return buffer_len(&active_state->output) < 128 * 1024;
1797 }
1798 
1799 static void
1800 packet_set_tos(int tos)
1801 {
1802 #ifndef IP_TOS_IS_BROKEN
1803 	if (!packet_connection_is_on_socket())
1804 		return;
1805 	switch (packet_connection_af()) {
1806 # ifdef IP_TOS
1807 	case AF_INET:
1808 		debug3("%s: set IP_TOS 0x%02x", __func__, tos);
1809 		if (setsockopt(active_state->connection_in,
1810 		    IPPROTO_IP, IP_TOS, &tos, sizeof(tos)) < 0)
1811 			error("setsockopt IP_TOS %d: %.100s:",
1812 			    tos, strerror(errno));
1813 		break;
1814 # endif /* IP_TOS */
1815 # ifdef IPV6_TCLASS
1816 	case AF_INET6:
1817 		debug3("%s: set IPV6_TCLASS 0x%02x", __func__, tos);
1818 		if (setsockopt(active_state->connection_in,
1819 		    IPPROTO_IPV6, IPV6_TCLASS, &tos, sizeof(tos)) < 0)
1820 			error("setsockopt IPV6_TCLASS %d: %.100s:",
1821 			    tos, strerror(errno));
1822 		break;
1823 # endif /* IPV6_TCLASS */
1824 	}
1825 #endif /* IP_TOS_IS_BROKEN */
1826 }
1827 
1828 /* Informs that the current session is interactive.  Sets IP flags for that. */
1829 
1830 void
1831 packet_set_interactive(int interactive, int qos_interactive, int qos_bulk)
1832 {
1833 	if (active_state->set_interactive_called)
1834 		return;
1835 	active_state->set_interactive_called = 1;
1836 
1837 	/* Record that we are in interactive mode. */
1838 	active_state->interactive_mode = interactive;
1839 
1840 	/* Only set socket options if using a socket.  */
1841 	if (!packet_connection_is_on_socket())
1842 		return;
1843 	set_nodelay(active_state->connection_in);
1844 	packet_set_tos(interactive ? qos_interactive : qos_bulk);
1845 }
1846 
1847 /* Returns true if the current connection is interactive. */
1848 
1849 int
1850 packet_is_interactive(void)
1851 {
1852 	return active_state->interactive_mode;
1853 }
1854 
1855 int
1856 packet_set_maxsize(u_int s)
1857 {
1858 	if (active_state->set_maxsize_called) {
1859 		logit("packet_set_maxsize: called twice: old %d new %d",
1860 		    active_state->max_packet_size, s);
1861 		return -1;
1862 	}
1863 	if (s < 4 * 1024 || s > 1024 * 1024) {
1864 		logit("packet_set_maxsize: bad size %d", s);
1865 		return -1;
1866 	}
1867 	active_state->set_maxsize_called = 1;
1868 	debug("packet_set_maxsize: setting to %d", s);
1869 	active_state->max_packet_size = s;
1870 	return s;
1871 }
1872 
1873 int
1874 packet_inc_alive_timeouts(void)
1875 {
1876 	return ++active_state->keep_alive_timeouts;
1877 }
1878 
1879 void
1880 packet_set_alive_timeouts(int ka)
1881 {
1882 	active_state->keep_alive_timeouts = ka;
1883 }
1884 
1885 u_int
1886 packet_get_maxsize(void)
1887 {
1888 	return active_state->max_packet_size;
1889 }
1890 
1891 /* roundup current message to pad bytes */
1892 void
1893 packet_add_padding(u_char pad)
1894 {
1895 	active_state->extra_pad = pad;
1896 }
1897 
1898 /*
1899  * 9.2.  Ignored Data Message
1900  *
1901  *   byte      SSH_MSG_IGNORE
1902  *   string    data
1903  *
1904  * All implementations MUST understand (and ignore) this message at any
1905  * time (after receiving the protocol version). No implementation is
1906  * required to send them. This message can be used as an additional
1907  * protection measure against advanced traffic analysis techniques.
1908  */
1909 void
1910 packet_send_ignore(int nbytes)
1911 {
1912 	u_int32_t rnd = 0;
1913 	int i;
1914 
1915 	packet_start(compat20 ? SSH2_MSG_IGNORE : SSH_MSG_IGNORE);
1916 	packet_put_int(nbytes);
1917 	for (i = 0; i < nbytes; i++) {
1918 		if (i % 4 == 0)
1919 			rnd = arc4random();
1920 		packet_put_char((u_char)rnd & 0xff);
1921 		rnd >>= 8;
1922 	}
1923 }
1924 
1925 #ifdef	NONE_CIPHER_ENABLED
1926 void
1927 packet_request_rekeying(void)
1928 {
1929 	rekey_requested = 1;
1930 }
1931 #endif
1932 
1933 #define MAX_PACKETS	(1U<<31)
1934 int
1935 packet_need_rekeying(void)
1936 {
1937 	if (datafellows & SSH_BUG_NOREKEY)
1938 		return 0;
1939 #ifdef	NONE_CIPHER_ENABLED
1940 	if (rekey_requested == 1) {
1941 		rekey_requested = 0;
1942 		return 1;
1943 	}
1944 #endif
1945 	return
1946 	    (active_state->p_send.packets > MAX_PACKETS) ||
1947 	    (active_state->p_read.packets > MAX_PACKETS) ||
1948 	    (active_state->max_blocks_out &&
1949 	        (active_state->p_send.blocks > active_state->max_blocks_out)) ||
1950 	    (active_state->max_blocks_in &&
1951 	        (active_state->p_read.blocks > active_state->max_blocks_in));
1952 }
1953 
1954 void
1955 packet_set_rekey_limit(u_int32_t bytes)
1956 {
1957 	active_state->rekey_limit = bytes;
1958 }
1959 
1960 void
1961 packet_set_server(void)
1962 {
1963 	active_state->server_side = 1;
1964 }
1965 
1966 void
1967 packet_set_authenticated(void)
1968 {
1969 	active_state->after_authentication = 1;
1970 }
1971 
1972 void *
1973 packet_get_input(void)
1974 {
1975 	return (void *)&active_state->input;
1976 }
1977 
1978 void *
1979 packet_get_output(void)
1980 {
1981 	return (void *)&active_state->output;
1982 }
1983 
1984 void *
1985 packet_get_newkeys(int mode)
1986 {
1987 	return (void *)active_state->newkeys[mode];
1988 }
1989 
1990 /*
1991  * Save the state for the real connection, and use a separate state when
1992  * resuming a suspended connection.
1993  */
1994 void
1995 packet_backup_state(void)
1996 {
1997 	struct session_state *tmp;
1998 
1999 	close(active_state->connection_in);
2000 	active_state->connection_in = -1;
2001 	close(active_state->connection_out);
2002 	active_state->connection_out = -1;
2003 	if (backup_state)
2004 		tmp = backup_state;
2005 	else
2006 		tmp = alloc_session_state();
2007 	backup_state = active_state;
2008 	active_state = tmp;
2009 }
2010 
2011 /*
2012  * Swap in the old state when resuming a connecion.
2013  */
2014 void
2015 packet_restore_state(void)
2016 {
2017 	struct session_state *tmp;
2018 	void *buf;
2019 	u_int len;
2020 
2021 	tmp = backup_state;
2022 	backup_state = active_state;
2023 	active_state = tmp;
2024 	active_state->connection_in = backup_state->connection_in;
2025 	backup_state->connection_in = -1;
2026 	active_state->connection_out = backup_state->connection_out;
2027 	backup_state->connection_out = -1;
2028 	len = buffer_len(&backup_state->input);
2029 	if (len > 0) {
2030 		buf = buffer_ptr(&backup_state->input);
2031 		buffer_append(&active_state->input, buf, len);
2032 		buffer_clear(&backup_state->input);
2033 		add_recv_bytes(len);
2034 	}
2035 }
2036 
2037 #ifdef	NONE_CIPHER_ENABLED
2038 int
2039 packet_get_authentication_state(void)
2040 {
2041 	return (active_state->after_authentication);
2042 }
2043 #endif
2044