xref: /openssh-portable/packet.c (revision f65cf116)
1 /* $OpenBSD: packet.c,v 1.287 2019/12/16 13:58:53 tobhe Exp $ */
2 /*
3  * Author: Tatu Ylonen <ylo@cs.hut.fi>
4  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5  *                    All rights reserved
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.
8  *
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".
14  *
15  *
16  * SSH2 packet format added by Markus Friedl.
17  * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
18  *
19  * Redistribution and use in source and binary forms, with or without
20  * modification, are permitted provided that the following conditions
21  * are met:
22  * 1. Redistributions of source code must retain the above copyright
23  *    notice, this list of conditions and the following disclaimer.
24  * 2. Redistributions in binary form must reproduce the above copyright
25  *    notice, this list of conditions and the following disclaimer in the
26  *    documentation and/or other materials provided with the distribution.
27  *
28  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
29  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
30  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
31  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
32  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
33  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
34  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
35  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
36  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
37  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
38  */
39 
40 #include "includes.h"
41 
42 #include <sys/types.h>
43 #include "openbsd-compat/sys-queue.h"
44 #include <sys/socket.h>
45 #ifdef HAVE_SYS_TIME_H
46 # include <sys/time.h>
47 #endif
48 
49 #include <netinet/in.h>
50 #include <netinet/ip.h>
51 #include <arpa/inet.h>
52 
53 #include <errno.h>
54 #include <netdb.h>
55 #include <stdarg.h>
56 #include <stdio.h>
57 #include <stdlib.h>
58 #include <string.h>
59 #include <unistd.h>
60 #include <limits.h>
61 #ifdef HAVE_POLL_H
62 #include <poll.h>
63 #endif
64 #include <signal.h>
65 #include <time.h>
66 
67 /*
68  * Explicitly include OpenSSL before zlib as some versions of OpenSSL have
69  * "free_func" in their headers, which zlib typedefs.
70  */
71 #ifdef WITH_OPENSSL
72 # include <openssl/bn.h>
73 # include <openssl/evp.h>
74 # ifdef OPENSSL_HAS_ECC
75 #  include <openssl/ec.h>
76 # endif
77 #endif
78 
79 #include <zlib.h>
80 
81 #include "xmalloc.h"
82 #include "compat.h"
83 #include "ssh2.h"
84 #include "cipher.h"
85 #include "sshkey.h"
86 #include "kex.h"
87 #include "digest.h"
88 #include "mac.h"
89 #include "log.h"
90 #include "canohost.h"
91 #include "misc.h"
92 #include "channels.h"
93 #include "ssh.h"
94 #include "packet.h"
95 #include "ssherr.h"
96 #include "sshbuf.h"
97 
98 #ifdef PACKET_DEBUG
99 #define DBG(x) x
100 #else
101 #define DBG(x)
102 #endif
103 
104 #define PACKET_MAX_SIZE (256 * 1024)
105 
106 struct packet_state {
107 	u_int32_t seqnr;
108 	u_int32_t packets;
109 	u_int64_t blocks;
110 	u_int64_t bytes;
111 };
112 
113 struct packet {
114 	TAILQ_ENTRY(packet) next;
115 	u_char type;
116 	struct sshbuf *payload;
117 };
118 
119 struct session_state {
120 	/*
121 	 * This variable contains the file descriptors used for
122 	 * communicating with the other side.  connection_in is used for
123 	 * reading; connection_out for writing.  These can be the same
124 	 * descriptor, in which case it is assumed to be a socket.
125 	 */
126 	int connection_in;
127 	int connection_out;
128 
129 	/* Protocol flags for the remote side. */
130 	u_int remote_protocol_flags;
131 
132 	/* Encryption context for receiving data.  Only used for decryption. */
133 	struct sshcipher_ctx *receive_context;
134 
135 	/* Encryption context for sending data.  Only used for encryption. */
136 	struct sshcipher_ctx *send_context;
137 
138 	/* Buffer for raw input data from the socket. */
139 	struct sshbuf *input;
140 
141 	/* Buffer for raw output data going to the socket. */
142 	struct sshbuf *output;
143 
144 	/* Buffer for the partial outgoing packet being constructed. */
145 	struct sshbuf *outgoing_packet;
146 
147 	/* Buffer for the incoming packet currently being processed. */
148 	struct sshbuf *incoming_packet;
149 
150 	/* Scratch buffer for packet compression/decompression. */
151 	struct sshbuf *compression_buffer;
152 
153 	/* Incoming/outgoing compression dictionaries */
154 	z_stream compression_in_stream;
155 	z_stream compression_out_stream;
156 	int compression_in_started;
157 	int compression_out_started;
158 	int compression_in_failures;
159 	int compression_out_failures;
160 
161 	/* default maximum packet size */
162 	u_int max_packet_size;
163 
164 	/* Flag indicating whether this module has been initialized. */
165 	int initialized;
166 
167 	/* Set to true if the connection is interactive. */
168 	int interactive_mode;
169 
170 	/* Set to true if we are the server side. */
171 	int server_side;
172 
173 	/* Set to true if we are authenticated. */
174 	int after_authentication;
175 
176 	int keep_alive_timeouts;
177 
178 	/* The maximum time that we will wait to send or receive a packet */
179 	int packet_timeout_ms;
180 
181 	/* Session key information for Encryption and MAC */
182 	struct newkeys *newkeys[MODE_MAX];
183 	struct packet_state p_read, p_send;
184 
185 	/* Volume-based rekeying */
186 	u_int64_t max_blocks_in, max_blocks_out, rekey_limit;
187 
188 	/* Time-based rekeying */
189 	u_int32_t rekey_interval;	/* how often in seconds */
190 	time_t rekey_time;	/* time of last rekeying */
191 
192 	/* roundup current message to extra_pad bytes */
193 	u_char extra_pad;
194 
195 	/* XXX discard incoming data after MAC error */
196 	u_int packet_discard;
197 	size_t packet_discard_mac_already;
198 	struct sshmac *packet_discard_mac;
199 
200 	/* Used in packet_read_poll2() */
201 	u_int packlen;
202 
203 	/* Used in packet_send2 */
204 	int rekeying;
205 
206 	/* Used in ssh_packet_send_mux() */
207 	int mux;
208 
209 	/* Used in packet_set_interactive */
210 	int set_interactive_called;
211 
212 	/* Used in packet_set_maxsize */
213 	int set_maxsize_called;
214 
215 	/* One-off warning about weak ciphers */
216 	int cipher_warning_done;
217 
218 	/* Hook for fuzzing inbound packets */
219 	ssh_packet_hook_fn *hook_in;
220 	void *hook_in_ctx;
221 
222 	TAILQ_HEAD(, packet) outgoing;
223 };
224 
225 struct ssh *
226 ssh_alloc_session_state(void)
227 {
228 	struct ssh *ssh = NULL;
229 	struct session_state *state = NULL;
230 
231 	if ((ssh = calloc(1, sizeof(*ssh))) == NULL ||
232 	    (state = calloc(1, sizeof(*state))) == NULL ||
233 	    (ssh->kex = kex_new()) == NULL ||
234 	    (state->input = sshbuf_new()) == NULL ||
235 	    (state->output = sshbuf_new()) == NULL ||
236 	    (state->outgoing_packet = sshbuf_new()) == NULL ||
237 	    (state->incoming_packet = sshbuf_new()) == NULL)
238 		goto fail;
239 	TAILQ_INIT(&state->outgoing);
240 	TAILQ_INIT(&ssh->private_keys);
241 	TAILQ_INIT(&ssh->public_keys);
242 	state->connection_in = -1;
243 	state->connection_out = -1;
244 	state->max_packet_size = 32768;
245 	state->packet_timeout_ms = -1;
246 	state->p_send.packets = state->p_read.packets = 0;
247 	state->initialized = 1;
248 	/*
249 	 * ssh_packet_send2() needs to queue packets until
250 	 * we've done the initial key exchange.
251 	 */
252 	state->rekeying = 1;
253 	ssh->state = state;
254 	return ssh;
255  fail:
256 	if (ssh) {
257 		kex_free(ssh->kex);
258 		free(ssh);
259 	}
260 	if (state) {
261 		sshbuf_free(state->input);
262 		sshbuf_free(state->output);
263 		sshbuf_free(state->incoming_packet);
264 		sshbuf_free(state->outgoing_packet);
265 		free(state);
266 	}
267 	return NULL;
268 }
269 
270 void
271 ssh_packet_set_input_hook(struct ssh *ssh, ssh_packet_hook_fn *hook, void *ctx)
272 {
273 	ssh->state->hook_in = hook;
274 	ssh->state->hook_in_ctx = ctx;
275 }
276 
277 /* Returns nonzero if rekeying is in progress */
278 int
279 ssh_packet_is_rekeying(struct ssh *ssh)
280 {
281 	return ssh->state->rekeying || ssh->kex->done == 0;
282 }
283 
284 /*
285  * Sets the descriptors used for communication.
286  */
287 struct ssh *
288 ssh_packet_set_connection(struct ssh *ssh, int fd_in, int fd_out)
289 {
290 	struct session_state *state;
291 	const struct sshcipher *none = cipher_by_name("none");
292 	int r;
293 
294 	if (none == NULL) {
295 		error("%s: cannot load cipher 'none'", __func__);
296 		return NULL;
297 	}
298 	if (ssh == NULL)
299 		ssh = ssh_alloc_session_state();
300 	if (ssh == NULL) {
301 		error("%s: could not allocate state", __func__);
302 		return NULL;
303 	}
304 	state = ssh->state;
305 	state->connection_in = fd_in;
306 	state->connection_out = fd_out;
307 	if ((r = cipher_init(&state->send_context, none,
308 	    (const u_char *)"", 0, NULL, 0, CIPHER_ENCRYPT)) != 0 ||
309 	    (r = cipher_init(&state->receive_context, none,
310 	    (const u_char *)"", 0, NULL, 0, CIPHER_DECRYPT)) != 0) {
311 		error("%s: cipher_init failed: %s", __func__, ssh_err(r));
312 		free(ssh); /* XXX need ssh_free_session_state? */
313 		return NULL;
314 	}
315 	state->newkeys[MODE_IN] = state->newkeys[MODE_OUT] = NULL;
316 	/*
317 	 * Cache the IP address of the remote connection for use in error
318 	 * messages that might be generated after the connection has closed.
319 	 */
320 	(void)ssh_remote_ipaddr(ssh);
321 	return ssh;
322 }
323 
324 void
325 ssh_packet_set_timeout(struct ssh *ssh, int timeout, int count)
326 {
327 	struct session_state *state = ssh->state;
328 
329 	if (timeout <= 0 || count <= 0) {
330 		state->packet_timeout_ms = -1;
331 		return;
332 	}
333 	if ((INT_MAX / 1000) / count < timeout)
334 		state->packet_timeout_ms = INT_MAX;
335 	else
336 		state->packet_timeout_ms = timeout * count * 1000;
337 }
338 
339 void
340 ssh_packet_set_mux(struct ssh *ssh)
341 {
342 	ssh->state->mux = 1;
343 	ssh->state->rekeying = 0;
344 }
345 
346 int
347 ssh_packet_get_mux(struct ssh *ssh)
348 {
349 	return ssh->state->mux;
350 }
351 
352 int
353 ssh_packet_set_log_preamble(struct ssh *ssh, const char *fmt, ...)
354 {
355 	va_list args;
356 	int r;
357 
358 	free(ssh->log_preamble);
359 	if (fmt == NULL)
360 		ssh->log_preamble = NULL;
361 	else {
362 		va_start(args, fmt);
363 		r = vasprintf(&ssh->log_preamble, fmt, args);
364 		va_end(args);
365 		if (r < 0 || ssh->log_preamble == NULL)
366 			return SSH_ERR_ALLOC_FAIL;
367 	}
368 	return 0;
369 }
370 
371 int
372 ssh_packet_stop_discard(struct ssh *ssh)
373 {
374 	struct session_state *state = ssh->state;
375 	int r;
376 
377 	if (state->packet_discard_mac) {
378 		char buf[1024];
379 		size_t dlen = PACKET_MAX_SIZE;
380 
381 		if (dlen > state->packet_discard_mac_already)
382 			dlen -= state->packet_discard_mac_already;
383 		memset(buf, 'a', sizeof(buf));
384 		while (sshbuf_len(state->incoming_packet) < dlen)
385 			if ((r = sshbuf_put(state->incoming_packet, buf,
386 			    sizeof(buf))) != 0)
387 				return r;
388 		(void) mac_compute(state->packet_discard_mac,
389 		    state->p_read.seqnr,
390 		    sshbuf_ptr(state->incoming_packet), dlen,
391 		    NULL, 0);
392 	}
393 	logit("Finished discarding for %.200s port %d",
394 	    ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
395 	return SSH_ERR_MAC_INVALID;
396 }
397 
398 static int
399 ssh_packet_start_discard(struct ssh *ssh, struct sshenc *enc,
400     struct sshmac *mac, size_t mac_already, u_int discard)
401 {
402 	struct session_state *state = ssh->state;
403 	int r;
404 
405 	if (enc == NULL || !cipher_is_cbc(enc->cipher) || (mac && mac->etm)) {
406 		if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0)
407 			return r;
408 		return SSH_ERR_MAC_INVALID;
409 	}
410 	/*
411 	 * Record number of bytes over which the mac has already
412 	 * been computed in order to minimize timing attacks.
413 	 */
414 	if (mac && mac->enabled) {
415 		state->packet_discard_mac = mac;
416 		state->packet_discard_mac_already = mac_already;
417 	}
418 	if (sshbuf_len(state->input) >= discard)
419 		return ssh_packet_stop_discard(ssh);
420 	state->packet_discard = discard - sshbuf_len(state->input);
421 	return 0;
422 }
423 
424 /* Returns 1 if remote host is connected via socket, 0 if not. */
425 
426 int
427 ssh_packet_connection_is_on_socket(struct ssh *ssh)
428 {
429 	struct session_state *state;
430 	struct sockaddr_storage from, to;
431 	socklen_t fromlen, tolen;
432 
433 	if (ssh == NULL || ssh->state == NULL)
434 		return 0;
435 
436 	state = ssh->state;
437 	if (state->connection_in == -1 || state->connection_out == -1)
438 		return 0;
439 	/* filedescriptors in and out are the same, so it's a socket */
440 	if (state->connection_in == state->connection_out)
441 		return 1;
442 	fromlen = sizeof(from);
443 	memset(&from, 0, sizeof(from));
444 	if (getpeername(state->connection_in, (struct sockaddr *)&from,
445 	    &fromlen) == -1)
446 		return 0;
447 	tolen = sizeof(to);
448 	memset(&to, 0, sizeof(to));
449 	if (getpeername(state->connection_out, (struct sockaddr *)&to,
450 	    &tolen) == -1)
451 		return 0;
452 	if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0)
453 		return 0;
454 	if (from.ss_family != AF_INET && from.ss_family != AF_INET6)
455 		return 0;
456 	return 1;
457 }
458 
459 void
460 ssh_packet_get_bytes(struct ssh *ssh, u_int64_t *ibytes, u_int64_t *obytes)
461 {
462 	if (ibytes)
463 		*ibytes = ssh->state->p_read.bytes;
464 	if (obytes)
465 		*obytes = ssh->state->p_send.bytes;
466 }
467 
468 int
469 ssh_packet_connection_af(struct ssh *ssh)
470 {
471 	struct sockaddr_storage to;
472 	socklen_t tolen = sizeof(to);
473 
474 	memset(&to, 0, sizeof(to));
475 	if (getsockname(ssh->state->connection_out, (struct sockaddr *)&to,
476 	    &tolen) == -1)
477 		return 0;
478 #ifdef IPV4_IN_IPV6
479 	if (to.ss_family == AF_INET6 &&
480 	    IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)&to)->sin6_addr))
481 		return AF_INET;
482 #endif
483 	return to.ss_family;
484 }
485 
486 /* Sets the connection into non-blocking mode. */
487 
488 void
489 ssh_packet_set_nonblocking(struct ssh *ssh)
490 {
491 	/* Set the socket into non-blocking mode. */
492 	set_nonblock(ssh->state->connection_in);
493 
494 	if (ssh->state->connection_out != ssh->state->connection_in)
495 		set_nonblock(ssh->state->connection_out);
496 }
497 
498 /* Returns the socket used for reading. */
499 
500 int
501 ssh_packet_get_connection_in(struct ssh *ssh)
502 {
503 	return ssh->state->connection_in;
504 }
505 
506 /* Returns the descriptor used for writing. */
507 
508 int
509 ssh_packet_get_connection_out(struct ssh *ssh)
510 {
511 	return ssh->state->connection_out;
512 }
513 
514 /*
515  * Returns the IP-address of the remote host as a string.  The returned
516  * string must not be freed.
517  */
518 
519 const char *
520 ssh_remote_ipaddr(struct ssh *ssh)
521 {
522 	int sock;
523 
524 	/* Check whether we have cached the ipaddr. */
525 	if (ssh->remote_ipaddr == NULL) {
526 		if (ssh_packet_connection_is_on_socket(ssh)) {
527 			sock = ssh->state->connection_in;
528 			ssh->remote_ipaddr = get_peer_ipaddr(sock);
529 			ssh->remote_port = get_peer_port(sock);
530 			ssh->local_ipaddr = get_local_ipaddr(sock);
531 			ssh->local_port = get_local_port(sock);
532 		} else {
533 			ssh->remote_ipaddr = xstrdup("UNKNOWN");
534 			ssh->remote_port = 65535;
535 			ssh->local_ipaddr = xstrdup("UNKNOWN");
536 			ssh->local_port = 65535;
537 		}
538 	}
539 	return ssh->remote_ipaddr;
540 }
541 
542 /* Returns the port number of the remote host. */
543 
544 int
545 ssh_remote_port(struct ssh *ssh)
546 {
547 	(void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */
548 	return ssh->remote_port;
549 }
550 
551 /*
552  * Returns the IP-address of the local host as a string.  The returned
553  * string must not be freed.
554  */
555 
556 const char *
557 ssh_local_ipaddr(struct ssh *ssh)
558 {
559 	(void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */
560 	return ssh->local_ipaddr;
561 }
562 
563 /* Returns the port number of the local host. */
564 
565 int
566 ssh_local_port(struct ssh *ssh)
567 {
568 	(void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */
569 	return ssh->local_port;
570 }
571 
572 /* Returns the routing domain of the input socket, or NULL if unavailable */
573 const char *
574 ssh_packet_rdomain_in(struct ssh *ssh)
575 {
576 	if (ssh->rdomain_in != NULL)
577 		return ssh->rdomain_in;
578 	if (!ssh_packet_connection_is_on_socket(ssh))
579 		return NULL;
580 	ssh->rdomain_in = get_rdomain(ssh->state->connection_in);
581 	return ssh->rdomain_in;
582 }
583 
584 /* Closes the connection and clears and frees internal data structures. */
585 
586 static void
587 ssh_packet_close_internal(struct ssh *ssh, int do_close)
588 {
589 	struct session_state *state = ssh->state;
590 	u_int mode;
591 
592 	if (!state->initialized)
593 		return;
594 	state->initialized = 0;
595 	if (do_close) {
596 		if (state->connection_in == state->connection_out) {
597 			close(state->connection_out);
598 		} else {
599 			close(state->connection_in);
600 			close(state->connection_out);
601 		}
602 	}
603 	sshbuf_free(state->input);
604 	sshbuf_free(state->output);
605 	sshbuf_free(state->outgoing_packet);
606 	sshbuf_free(state->incoming_packet);
607 	for (mode = 0; mode < MODE_MAX; mode++) {
608 		kex_free_newkeys(state->newkeys[mode]);	/* current keys */
609 		state->newkeys[mode] = NULL;
610 		ssh_clear_newkeys(ssh, mode);		/* next keys */
611 	}
612 	/* compression state is in shared mem, so we can only release it once */
613 	if (do_close && state->compression_buffer) {
614 		sshbuf_free(state->compression_buffer);
615 		if (state->compression_out_started) {
616 			z_streamp stream = &state->compression_out_stream;
617 			debug("compress outgoing: "
618 			    "raw data %llu, compressed %llu, factor %.2f",
619 				(unsigned long long)stream->total_in,
620 				(unsigned long long)stream->total_out,
621 				stream->total_in == 0 ? 0.0 :
622 				(double) stream->total_out / stream->total_in);
623 			if (state->compression_out_failures == 0)
624 				deflateEnd(stream);
625 		}
626 		if (state->compression_in_started) {
627 			z_streamp stream = &state->compression_in_stream;
628 			debug("compress incoming: "
629 			    "raw data %llu, compressed %llu, factor %.2f",
630 			    (unsigned long long)stream->total_out,
631 			    (unsigned long long)stream->total_in,
632 			    stream->total_out == 0 ? 0.0 :
633 			    (double) stream->total_in / stream->total_out);
634 			if (state->compression_in_failures == 0)
635 				inflateEnd(stream);
636 		}
637 	}
638 	cipher_free(state->send_context);
639 	cipher_free(state->receive_context);
640 	state->send_context = state->receive_context = NULL;
641 	if (do_close) {
642 		free(ssh->local_ipaddr);
643 		ssh->local_ipaddr = NULL;
644 		free(ssh->remote_ipaddr);
645 		ssh->remote_ipaddr = NULL;
646 		free(ssh->state);
647 		ssh->state = NULL;
648 	}
649 }
650 
651 void
652 ssh_packet_close(struct ssh *ssh)
653 {
654 	ssh_packet_close_internal(ssh, 1);
655 }
656 
657 void
658 ssh_packet_clear_keys(struct ssh *ssh)
659 {
660 	ssh_packet_close_internal(ssh, 0);
661 }
662 
663 /* Sets remote side protocol flags. */
664 
665 void
666 ssh_packet_set_protocol_flags(struct ssh *ssh, u_int protocol_flags)
667 {
668 	ssh->state->remote_protocol_flags = protocol_flags;
669 }
670 
671 /* Returns the remote protocol flags set earlier by the above function. */
672 
673 u_int
674 ssh_packet_get_protocol_flags(struct ssh *ssh)
675 {
676 	return ssh->state->remote_protocol_flags;
677 }
678 
679 /*
680  * Starts packet compression from the next packet on in both directions.
681  * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip.
682  */
683 
684 static int
685 ssh_packet_init_compression(struct ssh *ssh)
686 {
687 	if (!ssh->state->compression_buffer &&
688 	   ((ssh->state->compression_buffer = sshbuf_new()) == NULL))
689 		return SSH_ERR_ALLOC_FAIL;
690 	return 0;
691 }
692 
693 static int
694 start_compression_out(struct ssh *ssh, int level)
695 {
696 	if (level < 1 || level > 9)
697 		return SSH_ERR_INVALID_ARGUMENT;
698 	debug("Enabling compression at level %d.", level);
699 	if (ssh->state->compression_out_started == 1)
700 		deflateEnd(&ssh->state->compression_out_stream);
701 	switch (deflateInit(&ssh->state->compression_out_stream, level)) {
702 	case Z_OK:
703 		ssh->state->compression_out_started = 1;
704 		break;
705 	case Z_MEM_ERROR:
706 		return SSH_ERR_ALLOC_FAIL;
707 	default:
708 		return SSH_ERR_INTERNAL_ERROR;
709 	}
710 	return 0;
711 }
712 
713 static int
714 start_compression_in(struct ssh *ssh)
715 {
716 	if (ssh->state->compression_in_started == 1)
717 		inflateEnd(&ssh->state->compression_in_stream);
718 	switch (inflateInit(&ssh->state->compression_in_stream)) {
719 	case Z_OK:
720 		ssh->state->compression_in_started = 1;
721 		break;
722 	case Z_MEM_ERROR:
723 		return SSH_ERR_ALLOC_FAIL;
724 	default:
725 		return SSH_ERR_INTERNAL_ERROR;
726 	}
727 	return 0;
728 }
729 
730 /* XXX remove need for separate compression buffer */
731 static int
732 compress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out)
733 {
734 	u_char buf[4096];
735 	int r, status;
736 
737 	if (ssh->state->compression_out_started != 1)
738 		return SSH_ERR_INTERNAL_ERROR;
739 
740 	/* This case is not handled below. */
741 	if (sshbuf_len(in) == 0)
742 		return 0;
743 
744 	/* Input is the contents of the input buffer. */
745 	if ((ssh->state->compression_out_stream.next_in =
746 	    sshbuf_mutable_ptr(in)) == NULL)
747 		return SSH_ERR_INTERNAL_ERROR;
748 	ssh->state->compression_out_stream.avail_in = sshbuf_len(in);
749 
750 	/* Loop compressing until deflate() returns with avail_out != 0. */
751 	do {
752 		/* Set up fixed-size output buffer. */
753 		ssh->state->compression_out_stream.next_out = buf;
754 		ssh->state->compression_out_stream.avail_out = sizeof(buf);
755 
756 		/* Compress as much data into the buffer as possible. */
757 		status = deflate(&ssh->state->compression_out_stream,
758 		    Z_PARTIAL_FLUSH);
759 		switch (status) {
760 		case Z_MEM_ERROR:
761 			return SSH_ERR_ALLOC_FAIL;
762 		case Z_OK:
763 			/* Append compressed data to output_buffer. */
764 			if ((r = sshbuf_put(out, buf, sizeof(buf) -
765 			    ssh->state->compression_out_stream.avail_out)) != 0)
766 				return r;
767 			break;
768 		case Z_STREAM_ERROR:
769 		default:
770 			ssh->state->compression_out_failures++;
771 			return SSH_ERR_INVALID_FORMAT;
772 		}
773 	} while (ssh->state->compression_out_stream.avail_out == 0);
774 	return 0;
775 }
776 
777 static int
778 uncompress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out)
779 {
780 	u_char buf[4096];
781 	int r, status;
782 
783 	if (ssh->state->compression_in_started != 1)
784 		return SSH_ERR_INTERNAL_ERROR;
785 
786 	if ((ssh->state->compression_in_stream.next_in =
787 	    sshbuf_mutable_ptr(in)) == NULL)
788 		return SSH_ERR_INTERNAL_ERROR;
789 	ssh->state->compression_in_stream.avail_in = sshbuf_len(in);
790 
791 	for (;;) {
792 		/* Set up fixed-size output buffer. */
793 		ssh->state->compression_in_stream.next_out = buf;
794 		ssh->state->compression_in_stream.avail_out = sizeof(buf);
795 
796 		status = inflate(&ssh->state->compression_in_stream,
797 		    Z_PARTIAL_FLUSH);
798 		switch (status) {
799 		case Z_OK:
800 			if ((r = sshbuf_put(out, buf, sizeof(buf) -
801 			    ssh->state->compression_in_stream.avail_out)) != 0)
802 				return r;
803 			break;
804 		case Z_BUF_ERROR:
805 			/*
806 			 * Comments in zlib.h say that we should keep calling
807 			 * inflate() until we get an error.  This appears to
808 			 * be the error that we get.
809 			 */
810 			return 0;
811 		case Z_DATA_ERROR:
812 			return SSH_ERR_INVALID_FORMAT;
813 		case Z_MEM_ERROR:
814 			return SSH_ERR_ALLOC_FAIL;
815 		case Z_STREAM_ERROR:
816 		default:
817 			ssh->state->compression_in_failures++;
818 			return SSH_ERR_INTERNAL_ERROR;
819 		}
820 	}
821 	/* NOTREACHED */
822 }
823 
824 void
825 ssh_clear_newkeys(struct ssh *ssh, int mode)
826 {
827 	if (ssh->kex && ssh->kex->newkeys[mode]) {
828 		kex_free_newkeys(ssh->kex->newkeys[mode]);
829 		ssh->kex->newkeys[mode] = NULL;
830 	}
831 }
832 
833 int
834 ssh_set_newkeys(struct ssh *ssh, int mode)
835 {
836 	struct session_state *state = ssh->state;
837 	struct sshenc *enc;
838 	struct sshmac *mac;
839 	struct sshcomp *comp;
840 	struct sshcipher_ctx **ccp;
841 	struct packet_state *ps;
842 	u_int64_t *max_blocks;
843 	const char *wmsg;
844 	int r, crypt_type;
845 	const char *dir = mode == MODE_OUT ? "out" : "in";
846 
847 	debug2("set_newkeys: mode %d", mode);
848 
849 	if (mode == MODE_OUT) {
850 		ccp = &state->send_context;
851 		crypt_type = CIPHER_ENCRYPT;
852 		ps = &state->p_send;
853 		max_blocks = &state->max_blocks_out;
854 	} else {
855 		ccp = &state->receive_context;
856 		crypt_type = CIPHER_DECRYPT;
857 		ps = &state->p_read;
858 		max_blocks = &state->max_blocks_in;
859 	}
860 	if (state->newkeys[mode] != NULL) {
861 		debug("%s: rekeying %s, input %llu bytes %llu blocks, "
862 		   "output %llu bytes %llu blocks", __func__, dir,
863 		   (unsigned long long)state->p_read.bytes,
864 		   (unsigned long long)state->p_read.blocks,
865 		   (unsigned long long)state->p_send.bytes,
866 		   (unsigned long long)state->p_send.blocks);
867 		kex_free_newkeys(state->newkeys[mode]);
868 		state->newkeys[mode] = NULL;
869 	}
870 	/* note that both bytes and the seqnr are not reset */
871 	ps->packets = ps->blocks = 0;
872 	/* move newkeys from kex to state */
873 	if ((state->newkeys[mode] = ssh->kex->newkeys[mode]) == NULL)
874 		return SSH_ERR_INTERNAL_ERROR;
875 	ssh->kex->newkeys[mode] = NULL;
876 	enc  = &state->newkeys[mode]->enc;
877 	mac  = &state->newkeys[mode]->mac;
878 	comp = &state->newkeys[mode]->comp;
879 	if (cipher_authlen(enc->cipher) == 0) {
880 		if ((r = mac_init(mac)) != 0)
881 			return r;
882 	}
883 	mac->enabled = 1;
884 	DBG(debug("%s: cipher_init_context: %s", __func__, dir));
885 	cipher_free(*ccp);
886 	*ccp = NULL;
887 	if ((r = cipher_init(ccp, enc->cipher, enc->key, enc->key_len,
888 	    enc->iv, enc->iv_len, crypt_type)) != 0)
889 		return r;
890 	if (!state->cipher_warning_done &&
891 	    (wmsg = cipher_warning_message(*ccp)) != NULL) {
892 		error("Warning: %s", wmsg);
893 		state->cipher_warning_done = 1;
894 	}
895 	/* Deleting the keys does not gain extra security */
896 	/* explicit_bzero(enc->iv,  enc->block_size);
897 	   explicit_bzero(enc->key, enc->key_len);
898 	   explicit_bzero(mac->key, mac->key_len); */
899 	if ((comp->type == COMP_ZLIB ||
900 	    (comp->type == COMP_DELAYED &&
901 	     state->after_authentication)) && comp->enabled == 0) {
902 		if ((r = ssh_packet_init_compression(ssh)) < 0)
903 			return r;
904 		if (mode == MODE_OUT) {
905 			if ((r = start_compression_out(ssh, 6)) != 0)
906 				return r;
907 		} else {
908 			if ((r = start_compression_in(ssh)) != 0)
909 				return r;
910 		}
911 		comp->enabled = 1;
912 	}
913 	/*
914 	 * The 2^(blocksize*2) limit is too expensive for 3DES,
915 	 * so enforce a 1GB limit for small blocksizes.
916 	 * See RFC4344 section 3.2.
917 	 */
918 	if (enc->block_size >= 16)
919 		*max_blocks = (u_int64_t)1 << (enc->block_size*2);
920 	else
921 		*max_blocks = ((u_int64_t)1 << 30) / enc->block_size;
922 	if (state->rekey_limit)
923 		*max_blocks = MINIMUM(*max_blocks,
924 		    state->rekey_limit / enc->block_size);
925 	debug("rekey %s after %llu blocks", dir,
926 	    (unsigned long long)*max_blocks);
927 	return 0;
928 }
929 
930 #define MAX_PACKETS	(1U<<31)
931 static int
932 ssh_packet_need_rekeying(struct ssh *ssh, u_int outbound_packet_len)
933 {
934 	struct session_state *state = ssh->state;
935 	u_int32_t out_blocks;
936 
937 	/* XXX client can't cope with rekeying pre-auth */
938 	if (!state->after_authentication)
939 		return 0;
940 
941 	/* Haven't keyed yet or KEX in progress. */
942 	if (ssh_packet_is_rekeying(ssh))
943 		return 0;
944 
945 	/* Peer can't rekey */
946 	if (ssh->compat & SSH_BUG_NOREKEY)
947 		return 0;
948 
949 	/*
950 	 * Permit one packet in or out per rekey - this allows us to
951 	 * make progress when rekey limits are very small.
952 	 */
953 	if (state->p_send.packets == 0 && state->p_read.packets == 0)
954 		return 0;
955 
956 	/* Time-based rekeying */
957 	if (state->rekey_interval != 0 &&
958 	    (int64_t)state->rekey_time + state->rekey_interval <= monotime())
959 		return 1;
960 
961 	/*
962 	 * Always rekey when MAX_PACKETS sent in either direction
963 	 * As per RFC4344 section 3.1 we do this after 2^31 packets.
964 	 */
965 	if (state->p_send.packets > MAX_PACKETS ||
966 	    state->p_read.packets > MAX_PACKETS)
967 		return 1;
968 
969 	/* Rekey after (cipher-specific) maximum blocks */
970 	out_blocks = ROUNDUP(outbound_packet_len,
971 	    state->newkeys[MODE_OUT]->enc.block_size);
972 	return (state->max_blocks_out &&
973 	    (state->p_send.blocks + out_blocks > state->max_blocks_out)) ||
974 	    (state->max_blocks_in &&
975 	    (state->p_read.blocks > state->max_blocks_in));
976 }
977 
978 /*
979  * Delayed compression for SSH2 is enabled after authentication:
980  * This happens on the server side after a SSH2_MSG_USERAUTH_SUCCESS is sent,
981  * and on the client side after a SSH2_MSG_USERAUTH_SUCCESS is received.
982  */
983 static int
984 ssh_packet_enable_delayed_compress(struct ssh *ssh)
985 {
986 	struct session_state *state = ssh->state;
987 	struct sshcomp *comp = NULL;
988 	int r, mode;
989 
990 	/*
991 	 * Remember that we are past the authentication step, so rekeying
992 	 * with COMP_DELAYED will turn on compression immediately.
993 	 */
994 	state->after_authentication = 1;
995 	for (mode = 0; mode < MODE_MAX; mode++) {
996 		/* protocol error: USERAUTH_SUCCESS received before NEWKEYS */
997 		if (state->newkeys[mode] == NULL)
998 			continue;
999 		comp = &state->newkeys[mode]->comp;
1000 		if (comp && !comp->enabled && comp->type == COMP_DELAYED) {
1001 			if ((r = ssh_packet_init_compression(ssh)) != 0)
1002 				return r;
1003 			if (mode == MODE_OUT) {
1004 				if ((r = start_compression_out(ssh, 6)) != 0)
1005 					return r;
1006 			} else {
1007 				if ((r = start_compression_in(ssh)) != 0)
1008 					return r;
1009 			}
1010 			comp->enabled = 1;
1011 		}
1012 	}
1013 	return 0;
1014 }
1015 
1016 /* Used to mute debug logging for noisy packet types */
1017 int
1018 ssh_packet_log_type(u_char type)
1019 {
1020 	switch (type) {
1021 	case SSH2_MSG_CHANNEL_DATA:
1022 	case SSH2_MSG_CHANNEL_EXTENDED_DATA:
1023 	case SSH2_MSG_CHANNEL_WINDOW_ADJUST:
1024 		return 0;
1025 	default:
1026 		return 1;
1027 	}
1028 }
1029 
1030 /*
1031  * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue)
1032  */
1033 int
1034 ssh_packet_send2_wrapped(struct ssh *ssh)
1035 {
1036 	struct session_state *state = ssh->state;
1037 	u_char type, *cp, macbuf[SSH_DIGEST_MAX_LENGTH];
1038 	u_char tmp, padlen, pad = 0;
1039 	u_int authlen = 0, aadlen = 0;
1040 	u_int len;
1041 	struct sshenc *enc   = NULL;
1042 	struct sshmac *mac   = NULL;
1043 	struct sshcomp *comp = NULL;
1044 	int r, block_size;
1045 
1046 	if (state->newkeys[MODE_OUT] != NULL) {
1047 		enc  = &state->newkeys[MODE_OUT]->enc;
1048 		mac  = &state->newkeys[MODE_OUT]->mac;
1049 		comp = &state->newkeys[MODE_OUT]->comp;
1050 		/* disable mac for authenticated encryption */
1051 		if ((authlen = cipher_authlen(enc->cipher)) != 0)
1052 			mac = NULL;
1053 	}
1054 	block_size = enc ? enc->block_size : 8;
1055 	aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0;
1056 
1057 	type = (sshbuf_ptr(state->outgoing_packet))[5];
1058 	if (ssh_packet_log_type(type))
1059 		debug3("send packet: type %u", type);
1060 #ifdef PACKET_DEBUG
1061 	fprintf(stderr, "plain:     ");
1062 	sshbuf_dump(state->outgoing_packet, stderr);
1063 #endif
1064 
1065 	if (comp && comp->enabled) {
1066 		len = sshbuf_len(state->outgoing_packet);
1067 		/* skip header, compress only payload */
1068 		if ((r = sshbuf_consume(state->outgoing_packet, 5)) != 0)
1069 			goto out;
1070 		sshbuf_reset(state->compression_buffer);
1071 		if ((r = compress_buffer(ssh, state->outgoing_packet,
1072 		    state->compression_buffer)) != 0)
1073 			goto out;
1074 		sshbuf_reset(state->outgoing_packet);
1075 		if ((r = sshbuf_put(state->outgoing_packet,
1076 		    "\0\0\0\0\0", 5)) != 0 ||
1077 		    (r = sshbuf_putb(state->outgoing_packet,
1078 		    state->compression_buffer)) != 0)
1079 			goto out;
1080 		DBG(debug("compression: raw %d compressed %zd", len,
1081 		    sshbuf_len(state->outgoing_packet)));
1082 	}
1083 
1084 	/* sizeof (packet_len + pad_len + payload) */
1085 	len = sshbuf_len(state->outgoing_packet);
1086 
1087 	/*
1088 	 * calc size of padding, alloc space, get random data,
1089 	 * minimum padding is 4 bytes
1090 	 */
1091 	len -= aadlen; /* packet length is not encrypted for EtM modes */
1092 	padlen = block_size - (len % block_size);
1093 	if (padlen < 4)
1094 		padlen += block_size;
1095 	if (state->extra_pad) {
1096 		tmp = state->extra_pad;
1097 		state->extra_pad =
1098 		    ROUNDUP(state->extra_pad, block_size);
1099 		/* check if roundup overflowed */
1100 		if (state->extra_pad < tmp)
1101 			return SSH_ERR_INVALID_ARGUMENT;
1102 		tmp = (len + padlen) % state->extra_pad;
1103 		/* Check whether pad calculation below will underflow */
1104 		if (tmp > state->extra_pad)
1105 			return SSH_ERR_INVALID_ARGUMENT;
1106 		pad = state->extra_pad - tmp;
1107 		DBG(debug3("%s: adding %d (len %d padlen %d extra_pad %d)",
1108 		    __func__, pad, len, padlen, state->extra_pad));
1109 		tmp = padlen;
1110 		padlen += pad;
1111 		/* Check whether padlen calculation overflowed */
1112 		if (padlen < tmp)
1113 			return SSH_ERR_INVALID_ARGUMENT; /* overflow */
1114 		state->extra_pad = 0;
1115 	}
1116 	if ((r = sshbuf_reserve(state->outgoing_packet, padlen, &cp)) != 0)
1117 		goto out;
1118 	if (enc && !cipher_ctx_is_plaintext(state->send_context)) {
1119 		/* random padding */
1120 		arc4random_buf(cp, padlen);
1121 	} else {
1122 		/* clear padding */
1123 		explicit_bzero(cp, padlen);
1124 	}
1125 	/* sizeof (packet_len + pad_len + payload + padding) */
1126 	len = sshbuf_len(state->outgoing_packet);
1127 	cp = sshbuf_mutable_ptr(state->outgoing_packet);
1128 	if (cp == NULL) {
1129 		r = SSH_ERR_INTERNAL_ERROR;
1130 		goto out;
1131 	}
1132 	/* packet_length includes payload, padding and padding length field */
1133 	POKE_U32(cp, len - 4);
1134 	cp[4] = padlen;
1135 	DBG(debug("send: len %d (includes padlen %d, aadlen %d)",
1136 	    len, padlen, aadlen));
1137 
1138 	/* compute MAC over seqnr and packet(length fields, payload, padding) */
1139 	if (mac && mac->enabled && !mac->etm) {
1140 		if ((r = mac_compute(mac, state->p_send.seqnr,
1141 		    sshbuf_ptr(state->outgoing_packet), len,
1142 		    macbuf, sizeof(macbuf))) != 0)
1143 			goto out;
1144 		DBG(debug("done calc MAC out #%d", state->p_send.seqnr));
1145 	}
1146 	/* encrypt packet and append to output buffer. */
1147 	if ((r = sshbuf_reserve(state->output,
1148 	    sshbuf_len(state->outgoing_packet) + authlen, &cp)) != 0)
1149 		goto out;
1150 	if ((r = cipher_crypt(state->send_context, state->p_send.seqnr, cp,
1151 	    sshbuf_ptr(state->outgoing_packet),
1152 	    len - aadlen, aadlen, authlen)) != 0)
1153 		goto out;
1154 	/* append unencrypted MAC */
1155 	if (mac && mac->enabled) {
1156 		if (mac->etm) {
1157 			/* EtM: compute mac over aadlen + cipher text */
1158 			if ((r = mac_compute(mac, state->p_send.seqnr,
1159 			    cp, len, macbuf, sizeof(macbuf))) != 0)
1160 				goto out;
1161 			DBG(debug("done calc MAC(EtM) out #%d",
1162 			    state->p_send.seqnr));
1163 		}
1164 		if ((r = sshbuf_put(state->output, macbuf, mac->mac_len)) != 0)
1165 			goto out;
1166 	}
1167 #ifdef PACKET_DEBUG
1168 	fprintf(stderr, "encrypted: ");
1169 	sshbuf_dump(state->output, stderr);
1170 #endif
1171 	/* increment sequence number for outgoing packets */
1172 	if (++state->p_send.seqnr == 0)
1173 		logit("outgoing seqnr wraps around");
1174 	if (++state->p_send.packets == 0)
1175 		if (!(ssh->compat & SSH_BUG_NOREKEY))
1176 			return SSH_ERR_NEED_REKEY;
1177 	state->p_send.blocks += len / block_size;
1178 	state->p_send.bytes += len;
1179 	sshbuf_reset(state->outgoing_packet);
1180 
1181 	if (type == SSH2_MSG_NEWKEYS)
1182 		r = ssh_set_newkeys(ssh, MODE_OUT);
1183 	else if (type == SSH2_MSG_USERAUTH_SUCCESS && state->server_side)
1184 		r = ssh_packet_enable_delayed_compress(ssh);
1185 	else
1186 		r = 0;
1187  out:
1188 	return r;
1189 }
1190 
1191 /* returns non-zero if the specified packet type is usec by KEX */
1192 static int
1193 ssh_packet_type_is_kex(u_char type)
1194 {
1195 	return
1196 	    type >= SSH2_MSG_TRANSPORT_MIN &&
1197 	    type <= SSH2_MSG_TRANSPORT_MAX &&
1198 	    type != SSH2_MSG_SERVICE_REQUEST &&
1199 	    type != SSH2_MSG_SERVICE_ACCEPT &&
1200 	    type != SSH2_MSG_EXT_INFO;
1201 }
1202 
1203 int
1204 ssh_packet_send2(struct ssh *ssh)
1205 {
1206 	struct session_state *state = ssh->state;
1207 	struct packet *p;
1208 	u_char type;
1209 	int r, need_rekey;
1210 
1211 	if (sshbuf_len(state->outgoing_packet) < 6)
1212 		return SSH_ERR_INTERNAL_ERROR;
1213 	type = sshbuf_ptr(state->outgoing_packet)[5];
1214 	need_rekey = !ssh_packet_type_is_kex(type) &&
1215 	    ssh_packet_need_rekeying(ssh, sshbuf_len(state->outgoing_packet));
1216 
1217 	/*
1218 	 * During rekeying we can only send key exchange messages.
1219 	 * Queue everything else.
1220 	 */
1221 	if ((need_rekey || state->rekeying) && !ssh_packet_type_is_kex(type)) {
1222 		if (need_rekey)
1223 			debug3("%s: rekex triggered", __func__);
1224 		debug("enqueue packet: %u", type);
1225 		p = calloc(1, sizeof(*p));
1226 		if (p == NULL)
1227 			return SSH_ERR_ALLOC_FAIL;
1228 		p->type = type;
1229 		p->payload = state->outgoing_packet;
1230 		TAILQ_INSERT_TAIL(&state->outgoing, p, next);
1231 		state->outgoing_packet = sshbuf_new();
1232 		if (state->outgoing_packet == NULL)
1233 			return SSH_ERR_ALLOC_FAIL;
1234 		if (need_rekey) {
1235 			/*
1236 			 * This packet triggered a rekey, so send the
1237 			 * KEXINIT now.
1238 			 * NB. reenters this function via kex_start_rekex().
1239 			 */
1240 			return kex_start_rekex(ssh);
1241 		}
1242 		return 0;
1243 	}
1244 
1245 	/* rekeying starts with sending KEXINIT */
1246 	if (type == SSH2_MSG_KEXINIT)
1247 		state->rekeying = 1;
1248 
1249 	if ((r = ssh_packet_send2_wrapped(ssh)) != 0)
1250 		return r;
1251 
1252 	/* after a NEWKEYS message we can send the complete queue */
1253 	if (type == SSH2_MSG_NEWKEYS) {
1254 		state->rekeying = 0;
1255 		state->rekey_time = monotime();
1256 		while ((p = TAILQ_FIRST(&state->outgoing))) {
1257 			type = p->type;
1258 			/*
1259 			 * If this packet triggers a rekex, then skip the
1260 			 * remaining packets in the queue for now.
1261 			 * NB. re-enters this function via kex_start_rekex.
1262 			 */
1263 			if (ssh_packet_need_rekeying(ssh,
1264 			    sshbuf_len(p->payload))) {
1265 				debug3("%s: queued packet triggered rekex",
1266 				    __func__);
1267 				return kex_start_rekex(ssh);
1268 			}
1269 			debug("dequeue packet: %u", type);
1270 			sshbuf_free(state->outgoing_packet);
1271 			state->outgoing_packet = p->payload;
1272 			TAILQ_REMOVE(&state->outgoing, p, next);
1273 			memset(p, 0, sizeof(*p));
1274 			free(p);
1275 			if ((r = ssh_packet_send2_wrapped(ssh)) != 0)
1276 				return r;
1277 		}
1278 	}
1279 	return 0;
1280 }
1281 
1282 /*
1283  * Waits until a packet has been received, and returns its type.  Note that
1284  * no other data is processed until this returns, so this function should not
1285  * be used during the interactive session.
1286  */
1287 
1288 int
1289 ssh_packet_read_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
1290 {
1291 	struct session_state *state = ssh->state;
1292 	int len, r, ms_remain;
1293 	fd_set *setp;
1294 	char buf[8192];
1295 	struct timeval timeout, start, *timeoutp = NULL;
1296 
1297 	DBG(debug("packet_read()"));
1298 
1299 	setp = calloc(howmany(state->connection_in + 1,
1300 	    NFDBITS), sizeof(fd_mask));
1301 	if (setp == NULL)
1302 		return SSH_ERR_ALLOC_FAIL;
1303 
1304 	/*
1305 	 * Since we are blocking, ensure that all written packets have
1306 	 * been sent.
1307 	 */
1308 	if ((r = ssh_packet_write_wait(ssh)) != 0)
1309 		goto out;
1310 
1311 	/* Stay in the loop until we have received a complete packet. */
1312 	for (;;) {
1313 		/* Try to read a packet from the buffer. */
1314 		r = ssh_packet_read_poll_seqnr(ssh, typep, seqnr_p);
1315 		if (r != 0)
1316 			break;
1317 		/* If we got a packet, return it. */
1318 		if (*typep != SSH_MSG_NONE)
1319 			break;
1320 		/*
1321 		 * Otherwise, wait for some data to arrive, add it to the
1322 		 * buffer, and try again.
1323 		 */
1324 		memset(setp, 0, howmany(state->connection_in + 1,
1325 		    NFDBITS) * sizeof(fd_mask));
1326 		FD_SET(state->connection_in, setp);
1327 
1328 		if (state->packet_timeout_ms > 0) {
1329 			ms_remain = state->packet_timeout_ms;
1330 			timeoutp = &timeout;
1331 		}
1332 		/* Wait for some data to arrive. */
1333 		for (;;) {
1334 			if (state->packet_timeout_ms != -1) {
1335 				ms_to_timeval(&timeout, ms_remain);
1336 				monotime_tv(&start);
1337 			}
1338 			if ((r = select(state->connection_in + 1, setp,
1339 			    NULL, NULL, timeoutp)) >= 0)
1340 				break;
1341 			if (errno != EAGAIN && errno != EINTR &&
1342 			    errno != EWOULDBLOCK) {
1343 				r = SSH_ERR_SYSTEM_ERROR;
1344 				goto out;
1345 			}
1346 			if (state->packet_timeout_ms == -1)
1347 				continue;
1348 			ms_subtract_diff(&start, &ms_remain);
1349 			if (ms_remain <= 0) {
1350 				r = 0;
1351 				break;
1352 			}
1353 		}
1354 		if (r == 0) {
1355 			r = SSH_ERR_CONN_TIMEOUT;
1356 			goto out;
1357 		}
1358 		/* Read data from the socket. */
1359 		len = read(state->connection_in, buf, sizeof(buf));
1360 		if (len == 0) {
1361 			r = SSH_ERR_CONN_CLOSED;
1362 			goto out;
1363 		}
1364 		if (len == -1) {
1365 			r = SSH_ERR_SYSTEM_ERROR;
1366 			goto out;
1367 		}
1368 
1369 		/* Append it to the buffer. */
1370 		if ((r = ssh_packet_process_incoming(ssh, buf, len)) != 0)
1371 			goto out;
1372 	}
1373  out:
1374 	free(setp);
1375 	return r;
1376 }
1377 
1378 int
1379 ssh_packet_read(struct ssh *ssh)
1380 {
1381 	u_char type;
1382 	int r;
1383 
1384 	if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0)
1385 		fatal("%s: %s", __func__, ssh_err(r));
1386 	return type;
1387 }
1388 
1389 /*
1390  * Waits until a packet has been received, verifies that its type matches
1391  * that given, and gives a fatal error and exits if there is a mismatch.
1392  */
1393 
1394 int
1395 ssh_packet_read_expect(struct ssh *ssh, u_int expected_type)
1396 {
1397 	int r;
1398 	u_char type;
1399 
1400 	if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0)
1401 		return r;
1402 	if (type != expected_type) {
1403 		if ((r = sshpkt_disconnect(ssh,
1404 		    "Protocol error: expected packet type %d, got %d",
1405 		    expected_type, type)) != 0)
1406 			return r;
1407 		return SSH_ERR_PROTOCOL_ERROR;
1408 	}
1409 	return 0;
1410 }
1411 
1412 static int
1413 ssh_packet_read_poll2_mux(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
1414 {
1415 	struct session_state *state = ssh->state;
1416 	const u_char *cp;
1417 	size_t need;
1418 	int r;
1419 
1420 	if (ssh->kex)
1421 		return SSH_ERR_INTERNAL_ERROR;
1422 	*typep = SSH_MSG_NONE;
1423 	cp = sshbuf_ptr(state->input);
1424 	if (state->packlen == 0) {
1425 		if (sshbuf_len(state->input) < 4 + 1)
1426 			return 0; /* packet is incomplete */
1427 		state->packlen = PEEK_U32(cp);
1428 		if (state->packlen < 4 + 1 ||
1429 		    state->packlen > PACKET_MAX_SIZE)
1430 			return SSH_ERR_MESSAGE_INCOMPLETE;
1431 	}
1432 	need = state->packlen + 4;
1433 	if (sshbuf_len(state->input) < need)
1434 		return 0; /* packet is incomplete */
1435 	sshbuf_reset(state->incoming_packet);
1436 	if ((r = sshbuf_put(state->incoming_packet, cp + 4,
1437 	    state->packlen)) != 0 ||
1438 	    (r = sshbuf_consume(state->input, need)) != 0 ||
1439 	    (r = sshbuf_get_u8(state->incoming_packet, NULL)) != 0 ||
1440 	    (r = sshbuf_get_u8(state->incoming_packet, typep)) != 0)
1441 		return r;
1442 	if (ssh_packet_log_type(*typep))
1443 		debug3("%s: type %u", __func__, *typep);
1444 	/* sshbuf_dump(state->incoming_packet, stderr); */
1445 	/* reset for next packet */
1446 	state->packlen = 0;
1447 	return r;
1448 }
1449 
1450 int
1451 ssh_packet_read_poll2(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
1452 {
1453 	struct session_state *state = ssh->state;
1454 	u_int padlen, need;
1455 	u_char *cp;
1456 	u_int maclen, aadlen = 0, authlen = 0, block_size;
1457 	struct sshenc *enc   = NULL;
1458 	struct sshmac *mac   = NULL;
1459 	struct sshcomp *comp = NULL;
1460 	int r;
1461 
1462 	if (state->mux)
1463 		return ssh_packet_read_poll2_mux(ssh, typep, seqnr_p);
1464 
1465 	*typep = SSH_MSG_NONE;
1466 
1467 	if (state->packet_discard)
1468 		return 0;
1469 
1470 	if (state->newkeys[MODE_IN] != NULL) {
1471 		enc  = &state->newkeys[MODE_IN]->enc;
1472 		mac  = &state->newkeys[MODE_IN]->mac;
1473 		comp = &state->newkeys[MODE_IN]->comp;
1474 		/* disable mac for authenticated encryption */
1475 		if ((authlen = cipher_authlen(enc->cipher)) != 0)
1476 			mac = NULL;
1477 	}
1478 	maclen = mac && mac->enabled ? mac->mac_len : 0;
1479 	block_size = enc ? enc->block_size : 8;
1480 	aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0;
1481 
1482 	if (aadlen && state->packlen == 0) {
1483 		if (cipher_get_length(state->receive_context,
1484 		    &state->packlen, state->p_read.seqnr,
1485 		    sshbuf_ptr(state->input), sshbuf_len(state->input)) != 0)
1486 			return 0;
1487 		if (state->packlen < 1 + 4 ||
1488 		    state->packlen > PACKET_MAX_SIZE) {
1489 #ifdef PACKET_DEBUG
1490 			sshbuf_dump(state->input, stderr);
1491 #endif
1492 			logit("Bad packet length %u.", state->packlen);
1493 			if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0)
1494 				return r;
1495 			return SSH_ERR_CONN_CORRUPT;
1496 		}
1497 		sshbuf_reset(state->incoming_packet);
1498 	} else if (state->packlen == 0) {
1499 		/*
1500 		 * check if input size is less than the cipher block size,
1501 		 * decrypt first block and extract length of incoming packet
1502 		 */
1503 		if (sshbuf_len(state->input) < block_size)
1504 			return 0;
1505 		sshbuf_reset(state->incoming_packet);
1506 		if ((r = sshbuf_reserve(state->incoming_packet, block_size,
1507 		    &cp)) != 0)
1508 			goto out;
1509 		if ((r = cipher_crypt(state->receive_context,
1510 		    state->p_send.seqnr, cp, sshbuf_ptr(state->input),
1511 		    block_size, 0, 0)) != 0)
1512 			goto out;
1513 		state->packlen = PEEK_U32(sshbuf_ptr(state->incoming_packet));
1514 		if (state->packlen < 1 + 4 ||
1515 		    state->packlen > PACKET_MAX_SIZE) {
1516 #ifdef PACKET_DEBUG
1517 			fprintf(stderr, "input: \n");
1518 			sshbuf_dump(state->input, stderr);
1519 			fprintf(stderr, "incoming_packet: \n");
1520 			sshbuf_dump(state->incoming_packet, stderr);
1521 #endif
1522 			logit("Bad packet length %u.", state->packlen);
1523 			return ssh_packet_start_discard(ssh, enc, mac, 0,
1524 			    PACKET_MAX_SIZE);
1525 		}
1526 		if ((r = sshbuf_consume(state->input, block_size)) != 0)
1527 			goto out;
1528 	}
1529 	DBG(debug("input: packet len %u", state->packlen+4));
1530 
1531 	if (aadlen) {
1532 		/* only the payload is encrypted */
1533 		need = state->packlen;
1534 	} else {
1535 		/*
1536 		 * the payload size and the payload are encrypted, but we
1537 		 * have a partial packet of block_size bytes
1538 		 */
1539 		need = 4 + state->packlen - block_size;
1540 	}
1541 	DBG(debug("partial packet: block %d, need %d, maclen %d, authlen %d,"
1542 	    " aadlen %d", block_size, need, maclen, authlen, aadlen));
1543 	if (need % block_size != 0) {
1544 		logit("padding error: need %d block %d mod %d",
1545 		    need, block_size, need % block_size);
1546 		return ssh_packet_start_discard(ssh, enc, mac, 0,
1547 		    PACKET_MAX_SIZE - block_size);
1548 	}
1549 	/*
1550 	 * check if the entire packet has been received and
1551 	 * decrypt into incoming_packet:
1552 	 * 'aadlen' bytes are unencrypted, but authenticated.
1553 	 * 'need' bytes are encrypted, followed by either
1554 	 * 'authlen' bytes of authentication tag or
1555 	 * 'maclen' bytes of message authentication code.
1556 	 */
1557 	if (sshbuf_len(state->input) < aadlen + need + authlen + maclen)
1558 		return 0; /* packet is incomplete */
1559 #ifdef PACKET_DEBUG
1560 	fprintf(stderr, "read_poll enc/full: ");
1561 	sshbuf_dump(state->input, stderr);
1562 #endif
1563 	/* EtM: check mac over encrypted input */
1564 	if (mac && mac->enabled && mac->etm) {
1565 		if ((r = mac_check(mac, state->p_read.seqnr,
1566 		    sshbuf_ptr(state->input), aadlen + need,
1567 		    sshbuf_ptr(state->input) + aadlen + need + authlen,
1568 		    maclen)) != 0) {
1569 			if (r == SSH_ERR_MAC_INVALID)
1570 				logit("Corrupted MAC on input.");
1571 			goto out;
1572 		}
1573 	}
1574 	if ((r = sshbuf_reserve(state->incoming_packet, aadlen + need,
1575 	    &cp)) != 0)
1576 		goto out;
1577 	if ((r = cipher_crypt(state->receive_context, state->p_read.seqnr, cp,
1578 	    sshbuf_ptr(state->input), need, aadlen, authlen)) != 0)
1579 		goto out;
1580 	if ((r = sshbuf_consume(state->input, aadlen + need + authlen)) != 0)
1581 		goto out;
1582 	if (mac && mac->enabled) {
1583 		/* Not EtM: check MAC over cleartext */
1584 		if (!mac->etm && (r = mac_check(mac, state->p_read.seqnr,
1585 		    sshbuf_ptr(state->incoming_packet),
1586 		    sshbuf_len(state->incoming_packet),
1587 		    sshbuf_ptr(state->input), maclen)) != 0) {
1588 			if (r != SSH_ERR_MAC_INVALID)
1589 				goto out;
1590 			logit("Corrupted MAC on input.");
1591 			if (need + block_size > PACKET_MAX_SIZE)
1592 				return SSH_ERR_INTERNAL_ERROR;
1593 			return ssh_packet_start_discard(ssh, enc, mac,
1594 			    sshbuf_len(state->incoming_packet),
1595 			    PACKET_MAX_SIZE - need - block_size);
1596 		}
1597 		/* Remove MAC from input buffer */
1598 		DBG(debug("MAC #%d ok", state->p_read.seqnr));
1599 		if ((r = sshbuf_consume(state->input, mac->mac_len)) != 0)
1600 			goto out;
1601 	}
1602 	if (seqnr_p != NULL)
1603 		*seqnr_p = state->p_read.seqnr;
1604 	if (++state->p_read.seqnr == 0)
1605 		logit("incoming seqnr wraps around");
1606 	if (++state->p_read.packets == 0)
1607 		if (!(ssh->compat & SSH_BUG_NOREKEY))
1608 			return SSH_ERR_NEED_REKEY;
1609 	state->p_read.blocks += (state->packlen + 4) / block_size;
1610 	state->p_read.bytes += state->packlen + 4;
1611 
1612 	/* get padlen */
1613 	padlen = sshbuf_ptr(state->incoming_packet)[4];
1614 	DBG(debug("input: padlen %d", padlen));
1615 	if (padlen < 4)	{
1616 		if ((r = sshpkt_disconnect(ssh,
1617 		    "Corrupted padlen %d on input.", padlen)) != 0 ||
1618 		    (r = ssh_packet_write_wait(ssh)) != 0)
1619 			return r;
1620 		return SSH_ERR_CONN_CORRUPT;
1621 	}
1622 
1623 	/* skip packet size + padlen, discard padding */
1624 	if ((r = sshbuf_consume(state->incoming_packet, 4 + 1)) != 0 ||
1625 	    ((r = sshbuf_consume_end(state->incoming_packet, padlen)) != 0))
1626 		goto out;
1627 
1628 	DBG(debug("input: len before de-compress %zd",
1629 	    sshbuf_len(state->incoming_packet)));
1630 	if (comp && comp->enabled) {
1631 		sshbuf_reset(state->compression_buffer);
1632 		if ((r = uncompress_buffer(ssh, state->incoming_packet,
1633 		    state->compression_buffer)) != 0)
1634 			goto out;
1635 		sshbuf_reset(state->incoming_packet);
1636 		if ((r = sshbuf_putb(state->incoming_packet,
1637 		    state->compression_buffer)) != 0)
1638 			goto out;
1639 		DBG(debug("input: len after de-compress %zd",
1640 		    sshbuf_len(state->incoming_packet)));
1641 	}
1642 	/*
1643 	 * get packet type, implies consume.
1644 	 * return length of payload (without type field)
1645 	 */
1646 	if ((r = sshbuf_get_u8(state->incoming_packet, typep)) != 0)
1647 		goto out;
1648 	if (ssh_packet_log_type(*typep))
1649 		debug3("receive packet: type %u", *typep);
1650 	if (*typep < SSH2_MSG_MIN || *typep >= SSH2_MSG_LOCAL_MIN) {
1651 		if ((r = sshpkt_disconnect(ssh,
1652 		    "Invalid ssh2 packet type: %d", *typep)) != 0 ||
1653 		    (r = ssh_packet_write_wait(ssh)) != 0)
1654 			return r;
1655 		return SSH_ERR_PROTOCOL_ERROR;
1656 	}
1657 	if (state->hook_in != NULL &&
1658 	    (r = state->hook_in(ssh, state->incoming_packet, typep,
1659 	    state->hook_in_ctx)) != 0)
1660 		return r;
1661 	if (*typep == SSH2_MSG_USERAUTH_SUCCESS && !state->server_side)
1662 		r = ssh_packet_enable_delayed_compress(ssh);
1663 	else
1664 		r = 0;
1665 #ifdef PACKET_DEBUG
1666 	fprintf(stderr, "read/plain[%d]:\r\n", *typep);
1667 	sshbuf_dump(state->incoming_packet, stderr);
1668 #endif
1669 	/* reset for next packet */
1670 	state->packlen = 0;
1671 
1672 	/* do we need to rekey? */
1673 	if (ssh_packet_need_rekeying(ssh, 0)) {
1674 		debug3("%s: rekex triggered", __func__);
1675 		if ((r = kex_start_rekex(ssh)) != 0)
1676 			return r;
1677 	}
1678  out:
1679 	return r;
1680 }
1681 
1682 int
1683 ssh_packet_read_poll_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
1684 {
1685 	struct session_state *state = ssh->state;
1686 	u_int reason, seqnr;
1687 	int r;
1688 	u_char *msg;
1689 
1690 	for (;;) {
1691 		msg = NULL;
1692 		r = ssh_packet_read_poll2(ssh, typep, seqnr_p);
1693 		if (r != 0)
1694 			return r;
1695 		if (*typep) {
1696 			state->keep_alive_timeouts = 0;
1697 			DBG(debug("received packet type %d", *typep));
1698 		}
1699 		switch (*typep) {
1700 		case SSH2_MSG_IGNORE:
1701 			debug3("Received SSH2_MSG_IGNORE");
1702 			break;
1703 		case SSH2_MSG_DEBUG:
1704 			if ((r = sshpkt_get_u8(ssh, NULL)) != 0 ||
1705 			    (r = sshpkt_get_string(ssh, &msg, NULL)) != 0 ||
1706 			    (r = sshpkt_get_string(ssh, NULL, NULL)) != 0) {
1707 				free(msg);
1708 				return r;
1709 			}
1710 			debug("Remote: %.900s", msg);
1711 			free(msg);
1712 			break;
1713 		case SSH2_MSG_DISCONNECT:
1714 			if ((r = sshpkt_get_u32(ssh, &reason)) != 0 ||
1715 			    (r = sshpkt_get_string(ssh, &msg, NULL)) != 0)
1716 				return r;
1717 			/* Ignore normal client exit notifications */
1718 			do_log2(ssh->state->server_side &&
1719 			    reason == SSH2_DISCONNECT_BY_APPLICATION ?
1720 			    SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_ERROR,
1721 			    "Received disconnect from %s port %d:"
1722 			    "%u: %.400s", ssh_remote_ipaddr(ssh),
1723 			    ssh_remote_port(ssh), reason, msg);
1724 			free(msg);
1725 			return SSH_ERR_DISCONNECTED;
1726 		case SSH2_MSG_UNIMPLEMENTED:
1727 			if ((r = sshpkt_get_u32(ssh, &seqnr)) != 0)
1728 				return r;
1729 			debug("Received SSH2_MSG_UNIMPLEMENTED for %u",
1730 			    seqnr);
1731 			break;
1732 		default:
1733 			return 0;
1734 		}
1735 	}
1736 }
1737 
1738 /*
1739  * Buffers the given amount of input characters.  This is intended to be used
1740  * together with packet_read_poll.
1741  */
1742 
1743 int
1744 ssh_packet_process_incoming(struct ssh *ssh, const char *buf, u_int len)
1745 {
1746 	struct session_state *state = ssh->state;
1747 	int r;
1748 
1749 	if (state->packet_discard) {
1750 		state->keep_alive_timeouts = 0; /* ?? */
1751 		if (len >= state->packet_discard) {
1752 			if ((r = ssh_packet_stop_discard(ssh)) != 0)
1753 				return r;
1754 		}
1755 		state->packet_discard -= len;
1756 		return 0;
1757 	}
1758 	if ((r = sshbuf_put(ssh->state->input, buf, len)) != 0)
1759 		return r;
1760 
1761 	return 0;
1762 }
1763 
1764 int
1765 ssh_packet_remaining(struct ssh *ssh)
1766 {
1767 	return sshbuf_len(ssh->state->incoming_packet);
1768 }
1769 
1770 /*
1771  * Sends a diagnostic message from the server to the client.  This message
1772  * can be sent at any time (but not while constructing another message). The
1773  * message is printed immediately, but only if the client is being executed
1774  * in verbose mode.  These messages are primarily intended to ease debugging
1775  * authentication problems.   The length of the formatted message must not
1776  * exceed 1024 bytes.  This will automatically call ssh_packet_write_wait.
1777  */
1778 void
1779 ssh_packet_send_debug(struct ssh *ssh, const char *fmt,...)
1780 {
1781 	char buf[1024];
1782 	va_list args;
1783 	int r;
1784 
1785 	if ((ssh->compat & SSH_BUG_DEBUG))
1786 		return;
1787 
1788 	va_start(args, fmt);
1789 	vsnprintf(buf, sizeof(buf), fmt, args);
1790 	va_end(args);
1791 
1792 	debug3("sending debug message: %s", buf);
1793 
1794 	if ((r = sshpkt_start(ssh, SSH2_MSG_DEBUG)) != 0 ||
1795 	    (r = sshpkt_put_u8(ssh, 0)) != 0 || /* always display */
1796 	    (r = sshpkt_put_cstring(ssh, buf)) != 0 ||
1797 	    (r = sshpkt_put_cstring(ssh, "")) != 0 ||
1798 	    (r = sshpkt_send(ssh)) != 0 ||
1799 	    (r = ssh_packet_write_wait(ssh)) != 0)
1800 		fatal("%s: %s", __func__, ssh_err(r));
1801 }
1802 
1803 void
1804 sshpkt_fmt_connection_id(struct ssh *ssh, char *s, size_t l)
1805 {
1806 	snprintf(s, l, "%.200s%s%s port %d",
1807 	    ssh->log_preamble ? ssh->log_preamble : "",
1808 	    ssh->log_preamble ? " " : "",
1809 	    ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
1810 }
1811 
1812 /*
1813  * Pretty-print connection-terminating errors and exit.
1814  */
1815 static void
1816 sshpkt_vfatal(struct ssh *ssh, int r, const char *fmt, va_list ap)
1817 {
1818 	char *tag = NULL, remote_id[512];
1819 
1820 	sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id));
1821 
1822 	switch (r) {
1823 	case SSH_ERR_CONN_CLOSED:
1824 		ssh_packet_clear_keys(ssh);
1825 		logdie("Connection closed by %s", remote_id);
1826 	case SSH_ERR_CONN_TIMEOUT:
1827 		ssh_packet_clear_keys(ssh);
1828 		logdie("Connection %s %s timed out",
1829 		    ssh->state->server_side ? "from" : "to", remote_id);
1830 	case SSH_ERR_DISCONNECTED:
1831 		ssh_packet_clear_keys(ssh);
1832 		logdie("Disconnected from %s", remote_id);
1833 	case SSH_ERR_SYSTEM_ERROR:
1834 		if (errno == ECONNRESET) {
1835 			ssh_packet_clear_keys(ssh);
1836 			logdie("Connection reset by %s", remote_id);
1837 		}
1838 		/* FALLTHROUGH */
1839 	case SSH_ERR_NO_CIPHER_ALG_MATCH:
1840 	case SSH_ERR_NO_MAC_ALG_MATCH:
1841 	case SSH_ERR_NO_COMPRESS_ALG_MATCH:
1842 	case SSH_ERR_NO_KEX_ALG_MATCH:
1843 	case SSH_ERR_NO_HOSTKEY_ALG_MATCH:
1844 		if (ssh && ssh->kex && ssh->kex->failed_choice) {
1845 			ssh_packet_clear_keys(ssh);
1846 			logdie("Unable to negotiate with %s: %s. "
1847 			    "Their offer: %s", remote_id, ssh_err(r),
1848 			    ssh->kex->failed_choice);
1849 		}
1850 		/* FALLTHROUGH */
1851 	default:
1852 		if (vasprintf(&tag, fmt, ap) == -1) {
1853 			ssh_packet_clear_keys(ssh);
1854 			logdie("%s: could not allocate failure message",
1855 			    __func__);
1856 		}
1857 		ssh_packet_clear_keys(ssh);
1858 		logdie("%s%sConnection %s %s: %s",
1859 		    tag != NULL ? tag : "", tag != NULL ? ": " : "",
1860 		    ssh->state->server_side ? "from" : "to",
1861 		    remote_id, ssh_err(r));
1862 	}
1863 }
1864 
1865 void
1866 sshpkt_fatal(struct ssh *ssh, int r, const char *fmt, ...)
1867 {
1868 	va_list ap;
1869 
1870 	va_start(ap, fmt);
1871 	sshpkt_vfatal(ssh, r, fmt, ap);
1872 	/* NOTREACHED */
1873 	va_end(ap);
1874 	logdie("%s: should have exited", __func__);
1875 }
1876 
1877 /*
1878  * Logs the error plus constructs and sends a disconnect packet, closes the
1879  * connection, and exits.  This function never returns. The error message
1880  * should not contain a newline.  The length of the formatted message must
1881  * not exceed 1024 bytes.
1882  */
1883 void
1884 ssh_packet_disconnect(struct ssh *ssh, const char *fmt,...)
1885 {
1886 	char buf[1024], remote_id[512];
1887 	va_list args;
1888 	static int disconnecting = 0;
1889 	int r;
1890 
1891 	if (disconnecting)	/* Guard against recursive invocations. */
1892 		fatal("packet_disconnect called recursively.");
1893 	disconnecting = 1;
1894 
1895 	/*
1896 	 * Format the message.  Note that the caller must make sure the
1897 	 * message is of limited size.
1898 	 */
1899 	sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id));
1900 	va_start(args, fmt);
1901 	vsnprintf(buf, sizeof(buf), fmt, args);
1902 	va_end(args);
1903 
1904 	/* Display the error locally */
1905 	logit("Disconnecting %s: %.100s", remote_id, buf);
1906 
1907 	/*
1908 	 * Send the disconnect message to the other side, and wait
1909 	 * for it to get sent.
1910 	 */
1911 	if ((r = sshpkt_disconnect(ssh, "%s", buf)) != 0)
1912 		sshpkt_fatal(ssh, r, "%s", __func__);
1913 
1914 	if ((r = ssh_packet_write_wait(ssh)) != 0)
1915 		sshpkt_fatal(ssh, r, "%s", __func__);
1916 
1917 	/* Close the connection. */
1918 	ssh_packet_close(ssh);
1919 	cleanup_exit(255);
1920 }
1921 
1922 /*
1923  * Checks if there is any buffered output, and tries to write some of
1924  * the output.
1925  */
1926 int
1927 ssh_packet_write_poll(struct ssh *ssh)
1928 {
1929 	struct session_state *state = ssh->state;
1930 	int len = sshbuf_len(state->output);
1931 	int r;
1932 
1933 	if (len > 0) {
1934 		len = write(state->connection_out,
1935 		    sshbuf_ptr(state->output), len);
1936 		if (len == -1) {
1937 			if (errno == EINTR || errno == EAGAIN ||
1938 			    errno == EWOULDBLOCK)
1939 				return 0;
1940 			return SSH_ERR_SYSTEM_ERROR;
1941 		}
1942 		if (len == 0)
1943 			return SSH_ERR_CONN_CLOSED;
1944 		if ((r = sshbuf_consume(state->output, len)) != 0)
1945 			return r;
1946 	}
1947 	return 0;
1948 }
1949 
1950 /*
1951  * Calls packet_write_poll repeatedly until all pending output data has been
1952  * written.
1953  */
1954 int
1955 ssh_packet_write_wait(struct ssh *ssh)
1956 {
1957 	fd_set *setp;
1958 	int ret, r, ms_remain = 0;
1959 	struct timeval start, timeout, *timeoutp = NULL;
1960 	struct session_state *state = ssh->state;
1961 
1962 	setp = calloc(howmany(state->connection_out + 1,
1963 	    NFDBITS), sizeof(fd_mask));
1964 	if (setp == NULL)
1965 		return SSH_ERR_ALLOC_FAIL;
1966 	if ((r = ssh_packet_write_poll(ssh)) != 0) {
1967 		free(setp);
1968 		return r;
1969 	}
1970 	while (ssh_packet_have_data_to_write(ssh)) {
1971 		memset(setp, 0, howmany(state->connection_out + 1,
1972 		    NFDBITS) * sizeof(fd_mask));
1973 		FD_SET(state->connection_out, setp);
1974 
1975 		if (state->packet_timeout_ms > 0) {
1976 			ms_remain = state->packet_timeout_ms;
1977 			timeoutp = &timeout;
1978 		}
1979 		for (;;) {
1980 			if (state->packet_timeout_ms != -1) {
1981 				ms_to_timeval(&timeout, ms_remain);
1982 				monotime_tv(&start);
1983 			}
1984 			if ((ret = select(state->connection_out + 1,
1985 			    NULL, setp, NULL, timeoutp)) >= 0)
1986 				break;
1987 			if (errno != EAGAIN && errno != EINTR &&
1988 			    errno != EWOULDBLOCK)
1989 				break;
1990 			if (state->packet_timeout_ms == -1)
1991 				continue;
1992 			ms_subtract_diff(&start, &ms_remain);
1993 			if (ms_remain <= 0) {
1994 				ret = 0;
1995 				break;
1996 			}
1997 		}
1998 		if (ret == 0) {
1999 			free(setp);
2000 			return SSH_ERR_CONN_TIMEOUT;
2001 		}
2002 		if ((r = ssh_packet_write_poll(ssh)) != 0) {
2003 			free(setp);
2004 			return r;
2005 		}
2006 	}
2007 	free(setp);
2008 	return 0;
2009 }
2010 
2011 /* Returns true if there is buffered data to write to the connection. */
2012 
2013 int
2014 ssh_packet_have_data_to_write(struct ssh *ssh)
2015 {
2016 	return sshbuf_len(ssh->state->output) != 0;
2017 }
2018 
2019 /* Returns true if there is not too much data to write to the connection. */
2020 
2021 int
2022 ssh_packet_not_very_much_data_to_write(struct ssh *ssh)
2023 {
2024 	if (ssh->state->interactive_mode)
2025 		return sshbuf_len(ssh->state->output) < 16384;
2026 	else
2027 		return sshbuf_len(ssh->state->output) < 128 * 1024;
2028 }
2029 
2030 void
2031 ssh_packet_set_tos(struct ssh *ssh, int tos)
2032 {
2033 #ifndef IP_TOS_IS_BROKEN
2034 	if (!ssh_packet_connection_is_on_socket(ssh) || tos == INT_MAX)
2035 		return;
2036 	switch (ssh_packet_connection_af(ssh)) {
2037 # ifdef IP_TOS
2038 	case AF_INET:
2039 		debug3("%s: set IP_TOS 0x%02x", __func__, tos);
2040 		if (setsockopt(ssh->state->connection_in,
2041 		    IPPROTO_IP, IP_TOS, &tos, sizeof(tos)) == -1)
2042 			error("setsockopt IP_TOS %d: %.100s:",
2043 			    tos, strerror(errno));
2044 		break;
2045 # endif /* IP_TOS */
2046 # ifdef IPV6_TCLASS
2047 	case AF_INET6:
2048 		debug3("%s: set IPV6_TCLASS 0x%02x", __func__, tos);
2049 		if (setsockopt(ssh->state->connection_in,
2050 		    IPPROTO_IPV6, IPV6_TCLASS, &tos, sizeof(tos)) == -1)
2051 			error("setsockopt IPV6_TCLASS %d: %.100s:",
2052 			    tos, strerror(errno));
2053 		break;
2054 # endif /* IPV6_TCLASS */
2055 	}
2056 #endif /* IP_TOS_IS_BROKEN */
2057 }
2058 
2059 /* Informs that the current session is interactive.  Sets IP flags for that. */
2060 
2061 void
2062 ssh_packet_set_interactive(struct ssh *ssh, int interactive, int qos_interactive, int qos_bulk)
2063 {
2064 	struct session_state *state = ssh->state;
2065 
2066 	if (state->set_interactive_called)
2067 		return;
2068 	state->set_interactive_called = 1;
2069 
2070 	/* Record that we are in interactive mode. */
2071 	state->interactive_mode = interactive;
2072 
2073 	/* Only set socket options if using a socket.  */
2074 	if (!ssh_packet_connection_is_on_socket(ssh))
2075 		return;
2076 	set_nodelay(state->connection_in);
2077 	ssh_packet_set_tos(ssh, interactive ? qos_interactive :
2078 	    qos_bulk);
2079 }
2080 
2081 /* Returns true if the current connection is interactive. */
2082 
2083 int
2084 ssh_packet_is_interactive(struct ssh *ssh)
2085 {
2086 	return ssh->state->interactive_mode;
2087 }
2088 
2089 int
2090 ssh_packet_set_maxsize(struct ssh *ssh, u_int s)
2091 {
2092 	struct session_state *state = ssh->state;
2093 
2094 	if (state->set_maxsize_called) {
2095 		logit("packet_set_maxsize: called twice: old %d new %d",
2096 		    state->max_packet_size, s);
2097 		return -1;
2098 	}
2099 	if (s < 4 * 1024 || s > 1024 * 1024) {
2100 		logit("packet_set_maxsize: bad size %d", s);
2101 		return -1;
2102 	}
2103 	state->set_maxsize_called = 1;
2104 	debug("packet_set_maxsize: setting to %d", s);
2105 	state->max_packet_size = s;
2106 	return s;
2107 }
2108 
2109 int
2110 ssh_packet_inc_alive_timeouts(struct ssh *ssh)
2111 {
2112 	return ++ssh->state->keep_alive_timeouts;
2113 }
2114 
2115 void
2116 ssh_packet_set_alive_timeouts(struct ssh *ssh, int ka)
2117 {
2118 	ssh->state->keep_alive_timeouts = ka;
2119 }
2120 
2121 u_int
2122 ssh_packet_get_maxsize(struct ssh *ssh)
2123 {
2124 	return ssh->state->max_packet_size;
2125 }
2126 
2127 void
2128 ssh_packet_set_rekey_limits(struct ssh *ssh, u_int64_t bytes, u_int32_t seconds)
2129 {
2130 	debug3("rekey after %llu bytes, %u seconds", (unsigned long long)bytes,
2131 	    (unsigned int)seconds);
2132 	ssh->state->rekey_limit = bytes;
2133 	ssh->state->rekey_interval = seconds;
2134 }
2135 
2136 time_t
2137 ssh_packet_get_rekey_timeout(struct ssh *ssh)
2138 {
2139 	time_t seconds;
2140 
2141 	seconds = ssh->state->rekey_time + ssh->state->rekey_interval -
2142 	    monotime();
2143 	return (seconds <= 0 ? 1 : seconds);
2144 }
2145 
2146 void
2147 ssh_packet_set_server(struct ssh *ssh)
2148 {
2149 	ssh->state->server_side = 1;
2150 	ssh->kex->server = 1; /* XXX unify? */
2151 }
2152 
2153 void
2154 ssh_packet_set_authenticated(struct ssh *ssh)
2155 {
2156 	ssh->state->after_authentication = 1;
2157 }
2158 
2159 void *
2160 ssh_packet_get_input(struct ssh *ssh)
2161 {
2162 	return (void *)ssh->state->input;
2163 }
2164 
2165 void *
2166 ssh_packet_get_output(struct ssh *ssh)
2167 {
2168 	return (void *)ssh->state->output;
2169 }
2170 
2171 /* Reset after_authentication and reset compression in post-auth privsep */
2172 static int
2173 ssh_packet_set_postauth(struct ssh *ssh)
2174 {
2175 	int r;
2176 
2177 	debug("%s: called", __func__);
2178 	/* This was set in net child, but is not visible in user child */
2179 	ssh->state->after_authentication = 1;
2180 	ssh->state->rekeying = 0;
2181 	if ((r = ssh_packet_enable_delayed_compress(ssh)) != 0)
2182 		return r;
2183 	return 0;
2184 }
2185 
2186 /* Packet state (de-)serialization for privsep */
2187 
2188 /* turn kex into a blob for packet state serialization */
2189 static int
2190 kex_to_blob(struct sshbuf *m, struct kex *kex)
2191 {
2192 	int r;
2193 
2194 	if ((r = sshbuf_put_string(m, kex->session_id,
2195 	    kex->session_id_len)) != 0 ||
2196 	    (r = sshbuf_put_u32(m, kex->we_need)) != 0 ||
2197 	    (r = sshbuf_put_cstring(m, kex->hostkey_alg)) != 0 ||
2198 	    (r = sshbuf_put_u32(m, kex->hostkey_type)) != 0 ||
2199 	    (r = sshbuf_put_u32(m, kex->hostkey_nid)) != 0 ||
2200 	    (r = sshbuf_put_u32(m, kex->kex_type)) != 0 ||
2201 	    (r = sshbuf_put_stringb(m, kex->my)) != 0 ||
2202 	    (r = sshbuf_put_stringb(m, kex->peer)) != 0 ||
2203 	    (r = sshbuf_put_stringb(m, kex->client_version)) != 0 ||
2204 	    (r = sshbuf_put_stringb(m, kex->server_version)) != 0 ||
2205 	    (r = sshbuf_put_u32(m, kex->flags)) != 0)
2206 		return r;
2207 	return 0;
2208 }
2209 
2210 /* turn key exchange results into a blob for packet state serialization */
2211 static int
2212 newkeys_to_blob(struct sshbuf *m, struct ssh *ssh, int mode)
2213 {
2214 	struct sshbuf *b;
2215 	struct sshcipher_ctx *cc;
2216 	struct sshcomp *comp;
2217 	struct sshenc *enc;
2218 	struct sshmac *mac;
2219 	struct newkeys *newkey;
2220 	int r;
2221 
2222 	if ((newkey = ssh->state->newkeys[mode]) == NULL)
2223 		return SSH_ERR_INTERNAL_ERROR;
2224 	enc = &newkey->enc;
2225 	mac = &newkey->mac;
2226 	comp = &newkey->comp;
2227 	cc = (mode == MODE_OUT) ? ssh->state->send_context :
2228 	    ssh->state->receive_context;
2229 	if ((r = cipher_get_keyiv(cc, enc->iv, enc->iv_len)) != 0)
2230 		return r;
2231 	if ((b = sshbuf_new()) == NULL)
2232 		return SSH_ERR_ALLOC_FAIL;
2233 	if ((r = sshbuf_put_cstring(b, enc->name)) != 0 ||
2234 	    (r = sshbuf_put_u32(b, enc->enabled)) != 0 ||
2235 	    (r = sshbuf_put_u32(b, enc->block_size)) != 0 ||
2236 	    (r = sshbuf_put_string(b, enc->key, enc->key_len)) != 0 ||
2237 	    (r = sshbuf_put_string(b, enc->iv, enc->iv_len)) != 0)
2238 		goto out;
2239 	if (cipher_authlen(enc->cipher) == 0) {
2240 		if ((r = sshbuf_put_cstring(b, mac->name)) != 0 ||
2241 		    (r = sshbuf_put_u32(b, mac->enabled)) != 0 ||
2242 		    (r = sshbuf_put_string(b, mac->key, mac->key_len)) != 0)
2243 			goto out;
2244 	}
2245 	if ((r = sshbuf_put_u32(b, comp->type)) != 0 ||
2246 	    (r = sshbuf_put_cstring(b, comp->name)) != 0)
2247 		goto out;
2248 	r = sshbuf_put_stringb(m, b);
2249  out:
2250 	sshbuf_free(b);
2251 	return r;
2252 }
2253 
2254 /* serialize packet state into a blob */
2255 int
2256 ssh_packet_get_state(struct ssh *ssh, struct sshbuf *m)
2257 {
2258 	struct session_state *state = ssh->state;
2259 	int r;
2260 
2261 	if ((r = kex_to_blob(m, ssh->kex)) != 0 ||
2262 	    (r = newkeys_to_blob(m, ssh, MODE_OUT)) != 0 ||
2263 	    (r = newkeys_to_blob(m, ssh, MODE_IN)) != 0 ||
2264 	    (r = sshbuf_put_u64(m, state->rekey_limit)) != 0 ||
2265 	    (r = sshbuf_put_u32(m, state->rekey_interval)) != 0 ||
2266 	    (r = sshbuf_put_u32(m, state->p_send.seqnr)) != 0 ||
2267 	    (r = sshbuf_put_u64(m, state->p_send.blocks)) != 0 ||
2268 	    (r = sshbuf_put_u32(m, state->p_send.packets)) != 0 ||
2269 	    (r = sshbuf_put_u64(m, state->p_send.bytes)) != 0 ||
2270 	    (r = sshbuf_put_u32(m, state->p_read.seqnr)) != 0 ||
2271 	    (r = sshbuf_put_u64(m, state->p_read.blocks)) != 0 ||
2272 	    (r = sshbuf_put_u32(m, state->p_read.packets)) != 0 ||
2273 	    (r = sshbuf_put_u64(m, state->p_read.bytes)) != 0 ||
2274 	    (r = sshbuf_put_stringb(m, state->input)) != 0 ||
2275 	    (r = sshbuf_put_stringb(m, state->output)) != 0)
2276 		return r;
2277 
2278 	return 0;
2279 }
2280 
2281 /* restore key exchange results from blob for packet state de-serialization */
2282 static int
2283 newkeys_from_blob(struct sshbuf *m, struct ssh *ssh, int mode)
2284 {
2285 	struct sshbuf *b = NULL;
2286 	struct sshcomp *comp;
2287 	struct sshenc *enc;
2288 	struct sshmac *mac;
2289 	struct newkeys *newkey = NULL;
2290 	size_t keylen, ivlen, maclen;
2291 	int r;
2292 
2293 	if ((newkey = calloc(1, sizeof(*newkey))) == NULL) {
2294 		r = SSH_ERR_ALLOC_FAIL;
2295 		goto out;
2296 	}
2297 	if ((r = sshbuf_froms(m, &b)) != 0)
2298 		goto out;
2299 #ifdef DEBUG_PK
2300 	sshbuf_dump(b, stderr);
2301 #endif
2302 	enc = &newkey->enc;
2303 	mac = &newkey->mac;
2304 	comp = &newkey->comp;
2305 
2306 	if ((r = sshbuf_get_cstring(b, &enc->name, NULL)) != 0 ||
2307 	    (r = sshbuf_get_u32(b, (u_int *)&enc->enabled)) != 0 ||
2308 	    (r = sshbuf_get_u32(b, &enc->block_size)) != 0 ||
2309 	    (r = sshbuf_get_string(b, &enc->key, &keylen)) != 0 ||
2310 	    (r = sshbuf_get_string(b, &enc->iv, &ivlen)) != 0)
2311 		goto out;
2312 	if ((enc->cipher = cipher_by_name(enc->name)) == NULL) {
2313 		r = SSH_ERR_INVALID_FORMAT;
2314 		goto out;
2315 	}
2316 	if (cipher_authlen(enc->cipher) == 0) {
2317 		if ((r = sshbuf_get_cstring(b, &mac->name, NULL)) != 0)
2318 			goto out;
2319 		if ((r = mac_setup(mac, mac->name)) != 0)
2320 			goto out;
2321 		if ((r = sshbuf_get_u32(b, (u_int *)&mac->enabled)) != 0 ||
2322 		    (r = sshbuf_get_string(b, &mac->key, &maclen)) != 0)
2323 			goto out;
2324 		if (maclen > mac->key_len) {
2325 			r = SSH_ERR_INVALID_FORMAT;
2326 			goto out;
2327 		}
2328 		mac->key_len = maclen;
2329 	}
2330 	if ((r = sshbuf_get_u32(b, &comp->type)) != 0 ||
2331 	    (r = sshbuf_get_cstring(b, &comp->name, NULL)) != 0)
2332 		goto out;
2333 	if (sshbuf_len(b) != 0) {
2334 		r = SSH_ERR_INVALID_FORMAT;
2335 		goto out;
2336 	}
2337 	enc->key_len = keylen;
2338 	enc->iv_len = ivlen;
2339 	ssh->kex->newkeys[mode] = newkey;
2340 	newkey = NULL;
2341 	r = 0;
2342  out:
2343 	free(newkey);
2344 	sshbuf_free(b);
2345 	return r;
2346 }
2347 
2348 /* restore kex from blob for packet state de-serialization */
2349 static int
2350 kex_from_blob(struct sshbuf *m, struct kex **kexp)
2351 {
2352 	struct kex *kex;
2353 	int r;
2354 
2355 	if ((kex = kex_new()) == NULL)
2356 		return SSH_ERR_ALLOC_FAIL;
2357 	if ((r = sshbuf_get_string(m, &kex->session_id, &kex->session_id_len)) != 0 ||
2358 	    (r = sshbuf_get_u32(m, &kex->we_need)) != 0 ||
2359 	    (r = sshbuf_get_cstring(m, &kex->hostkey_alg, NULL)) != 0 ||
2360 	    (r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_type)) != 0 ||
2361 	    (r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_nid)) != 0 ||
2362 	    (r = sshbuf_get_u32(m, &kex->kex_type)) != 0 ||
2363 	    (r = sshbuf_get_stringb(m, kex->my)) != 0 ||
2364 	    (r = sshbuf_get_stringb(m, kex->peer)) != 0 ||
2365 	    (r = sshbuf_get_stringb(m, kex->client_version)) != 0 ||
2366 	    (r = sshbuf_get_stringb(m, kex->server_version)) != 0 ||
2367 	    (r = sshbuf_get_u32(m, &kex->flags)) != 0)
2368 		goto out;
2369 	kex->server = 1;
2370 	kex->done = 1;
2371 	r = 0;
2372  out:
2373 	if (r != 0 || kexp == NULL) {
2374 		kex_free(kex);
2375 		if (kexp != NULL)
2376 			*kexp = NULL;
2377 	} else {
2378 		kex_free(*kexp);
2379 		*kexp = kex;
2380 	}
2381 	return r;
2382 }
2383 
2384 /*
2385  * Restore packet state from content of blob 'm' (de-serialization).
2386  * Note that 'm' will be partially consumed on parsing or any other errors.
2387  */
2388 int
2389 ssh_packet_set_state(struct ssh *ssh, struct sshbuf *m)
2390 {
2391 	struct session_state *state = ssh->state;
2392 	const u_char *input, *output;
2393 	size_t ilen, olen;
2394 	int r;
2395 
2396 	if ((r = kex_from_blob(m, &ssh->kex)) != 0 ||
2397 	    (r = newkeys_from_blob(m, ssh, MODE_OUT)) != 0 ||
2398 	    (r = newkeys_from_blob(m, ssh, MODE_IN)) != 0 ||
2399 	    (r = sshbuf_get_u64(m, &state->rekey_limit)) != 0 ||
2400 	    (r = sshbuf_get_u32(m, &state->rekey_interval)) != 0 ||
2401 	    (r = sshbuf_get_u32(m, &state->p_send.seqnr)) != 0 ||
2402 	    (r = sshbuf_get_u64(m, &state->p_send.blocks)) != 0 ||
2403 	    (r = sshbuf_get_u32(m, &state->p_send.packets)) != 0 ||
2404 	    (r = sshbuf_get_u64(m, &state->p_send.bytes)) != 0 ||
2405 	    (r = sshbuf_get_u32(m, &state->p_read.seqnr)) != 0 ||
2406 	    (r = sshbuf_get_u64(m, &state->p_read.blocks)) != 0 ||
2407 	    (r = sshbuf_get_u32(m, &state->p_read.packets)) != 0 ||
2408 	    (r = sshbuf_get_u64(m, &state->p_read.bytes)) != 0)
2409 		return r;
2410 	/*
2411 	 * We set the time here so that in post-auth privsep slave we
2412 	 * count from the completion of the authentication.
2413 	 */
2414 	state->rekey_time = monotime();
2415 	/* XXX ssh_set_newkeys overrides p_read.packets? XXX */
2416 	if ((r = ssh_set_newkeys(ssh, MODE_IN)) != 0 ||
2417 	    (r = ssh_set_newkeys(ssh, MODE_OUT)) != 0)
2418 		return r;
2419 
2420 	if ((r = ssh_packet_set_postauth(ssh)) != 0)
2421 		return r;
2422 
2423 	sshbuf_reset(state->input);
2424 	sshbuf_reset(state->output);
2425 	if ((r = sshbuf_get_string_direct(m, &input, &ilen)) != 0 ||
2426 	    (r = sshbuf_get_string_direct(m, &output, &olen)) != 0 ||
2427 	    (r = sshbuf_put(state->input, input, ilen)) != 0 ||
2428 	    (r = sshbuf_put(state->output, output, olen)) != 0)
2429 		return r;
2430 
2431 	if (sshbuf_len(m))
2432 		return SSH_ERR_INVALID_FORMAT;
2433 	debug3("%s: done", __func__);
2434 	return 0;
2435 }
2436 
2437 /* NEW API */
2438 
2439 /* put data to the outgoing packet */
2440 
2441 int
2442 sshpkt_put(struct ssh *ssh, const void *v, size_t len)
2443 {
2444 	return sshbuf_put(ssh->state->outgoing_packet, v, len);
2445 }
2446 
2447 int
2448 sshpkt_putb(struct ssh *ssh, const struct sshbuf *b)
2449 {
2450 	return sshbuf_putb(ssh->state->outgoing_packet, b);
2451 }
2452 
2453 int
2454 sshpkt_put_u8(struct ssh *ssh, u_char val)
2455 {
2456 	return sshbuf_put_u8(ssh->state->outgoing_packet, val);
2457 }
2458 
2459 int
2460 sshpkt_put_u32(struct ssh *ssh, u_int32_t val)
2461 {
2462 	return sshbuf_put_u32(ssh->state->outgoing_packet, val);
2463 }
2464 
2465 int
2466 sshpkt_put_u64(struct ssh *ssh, u_int64_t val)
2467 {
2468 	return sshbuf_put_u64(ssh->state->outgoing_packet, val);
2469 }
2470 
2471 int
2472 sshpkt_put_string(struct ssh *ssh, const void *v, size_t len)
2473 {
2474 	return sshbuf_put_string(ssh->state->outgoing_packet, v, len);
2475 }
2476 
2477 int
2478 sshpkt_put_cstring(struct ssh *ssh, const void *v)
2479 {
2480 	return sshbuf_put_cstring(ssh->state->outgoing_packet, v);
2481 }
2482 
2483 int
2484 sshpkt_put_stringb(struct ssh *ssh, const struct sshbuf *v)
2485 {
2486 	return sshbuf_put_stringb(ssh->state->outgoing_packet, v);
2487 }
2488 
2489 int
2490 sshpkt_getb_froms(struct ssh *ssh, struct sshbuf **valp)
2491 {
2492 	return sshbuf_froms(ssh->state->incoming_packet, valp);
2493 }
2494 
2495 #ifdef WITH_OPENSSL
2496 #ifdef OPENSSL_HAS_ECC
2497 int
2498 sshpkt_put_ec(struct ssh *ssh, const EC_POINT *v, const EC_GROUP *g)
2499 {
2500 	return sshbuf_put_ec(ssh->state->outgoing_packet, v, g);
2501 }
2502 #endif /* OPENSSL_HAS_ECC */
2503 
2504 
2505 int
2506 sshpkt_put_bignum2(struct ssh *ssh, const BIGNUM *v)
2507 {
2508 	return sshbuf_put_bignum2(ssh->state->outgoing_packet, v);
2509 }
2510 #endif /* WITH_OPENSSL */
2511 
2512 /* fetch data from the incoming packet */
2513 
2514 int
2515 sshpkt_get(struct ssh *ssh, void *valp, size_t len)
2516 {
2517 	return sshbuf_get(ssh->state->incoming_packet, valp, len);
2518 }
2519 
2520 int
2521 sshpkt_get_u8(struct ssh *ssh, u_char *valp)
2522 {
2523 	return sshbuf_get_u8(ssh->state->incoming_packet, valp);
2524 }
2525 
2526 int
2527 sshpkt_get_u32(struct ssh *ssh, u_int32_t *valp)
2528 {
2529 	return sshbuf_get_u32(ssh->state->incoming_packet, valp);
2530 }
2531 
2532 int
2533 sshpkt_get_u64(struct ssh *ssh, u_int64_t *valp)
2534 {
2535 	return sshbuf_get_u64(ssh->state->incoming_packet, valp);
2536 }
2537 
2538 int
2539 sshpkt_get_string(struct ssh *ssh, u_char **valp, size_t *lenp)
2540 {
2541 	return sshbuf_get_string(ssh->state->incoming_packet, valp, lenp);
2542 }
2543 
2544 int
2545 sshpkt_get_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp)
2546 {
2547 	return sshbuf_get_string_direct(ssh->state->incoming_packet, valp, lenp);
2548 }
2549 
2550 int
2551 sshpkt_peek_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp)
2552 {
2553 	return sshbuf_peek_string_direct(ssh->state->incoming_packet, valp, lenp);
2554 }
2555 
2556 int
2557 sshpkt_get_cstring(struct ssh *ssh, char **valp, size_t *lenp)
2558 {
2559 	return sshbuf_get_cstring(ssh->state->incoming_packet, valp, lenp);
2560 }
2561 
2562 #ifdef WITH_OPENSSL
2563 #ifdef OPENSSL_HAS_ECC
2564 int
2565 sshpkt_get_ec(struct ssh *ssh, EC_POINT *v, const EC_GROUP *g)
2566 {
2567 	return sshbuf_get_ec(ssh->state->incoming_packet, v, g);
2568 }
2569 #endif /* OPENSSL_HAS_ECC */
2570 
2571 int
2572 sshpkt_get_bignum2(struct ssh *ssh, BIGNUM **valp)
2573 {
2574 	return sshbuf_get_bignum2(ssh->state->incoming_packet, valp);
2575 }
2576 #endif /* WITH_OPENSSL */
2577 
2578 int
2579 sshpkt_get_end(struct ssh *ssh)
2580 {
2581 	if (sshbuf_len(ssh->state->incoming_packet) > 0)
2582 		return SSH_ERR_UNEXPECTED_TRAILING_DATA;
2583 	return 0;
2584 }
2585 
2586 const u_char *
2587 sshpkt_ptr(struct ssh *ssh, size_t *lenp)
2588 {
2589 	if (lenp != NULL)
2590 		*lenp = sshbuf_len(ssh->state->incoming_packet);
2591 	return sshbuf_ptr(ssh->state->incoming_packet);
2592 }
2593 
2594 /* start a new packet */
2595 
2596 int
2597 sshpkt_start(struct ssh *ssh, u_char type)
2598 {
2599 	u_char buf[6]; /* u32 packet length, u8 pad len, u8 type */
2600 
2601 	DBG(debug("packet_start[%d]", type));
2602 	memset(buf, 0, sizeof(buf));
2603 	buf[sizeof(buf) - 1] = type;
2604 	sshbuf_reset(ssh->state->outgoing_packet);
2605 	return sshbuf_put(ssh->state->outgoing_packet, buf, sizeof(buf));
2606 }
2607 
2608 static int
2609 ssh_packet_send_mux(struct ssh *ssh)
2610 {
2611 	struct session_state *state = ssh->state;
2612 	u_char type, *cp;
2613 	size_t len;
2614 	int r;
2615 
2616 	if (ssh->kex)
2617 		return SSH_ERR_INTERNAL_ERROR;
2618 	len = sshbuf_len(state->outgoing_packet);
2619 	if (len < 6)
2620 		return SSH_ERR_INTERNAL_ERROR;
2621 	cp = sshbuf_mutable_ptr(state->outgoing_packet);
2622 	type = cp[5];
2623 	if (ssh_packet_log_type(type))
2624 		debug3("%s: type %u", __func__, type);
2625 	/* drop everything, but the connection protocol */
2626 	if (type >= SSH2_MSG_CONNECTION_MIN &&
2627 	    type <= SSH2_MSG_CONNECTION_MAX) {
2628 		POKE_U32(cp, len - 4);
2629 		if ((r = sshbuf_putb(state->output,
2630 		    state->outgoing_packet)) != 0)
2631 			return r;
2632 		/* sshbuf_dump(state->output, stderr); */
2633 	}
2634 	sshbuf_reset(state->outgoing_packet);
2635 	return 0;
2636 }
2637 
2638 /*
2639  * 9.2.  Ignored Data Message
2640  *
2641  *   byte      SSH_MSG_IGNORE
2642  *   string    data
2643  *
2644  * All implementations MUST understand (and ignore) this message at any
2645  * time (after receiving the protocol version). No implementation is
2646  * required to send them. This message can be used as an additional
2647  * protection measure against advanced traffic analysis techniques.
2648  */
2649 int
2650 sshpkt_msg_ignore(struct ssh *ssh, u_int nbytes)
2651 {
2652 	u_int32_t rnd = 0;
2653 	int r;
2654 	u_int i;
2655 
2656 	if ((r = sshpkt_start(ssh, SSH2_MSG_IGNORE)) != 0 ||
2657 	    (r = sshpkt_put_u32(ssh, nbytes)) != 0)
2658 		return r;
2659 	for (i = 0; i < nbytes; i++) {
2660 		if (i % 4 == 0)
2661 			rnd = arc4random();
2662 		if ((r = sshpkt_put_u8(ssh, (u_char)rnd & 0xff)) != 0)
2663 			return r;
2664 		rnd >>= 8;
2665 	}
2666 	return 0;
2667 }
2668 
2669 /* send it */
2670 
2671 int
2672 sshpkt_send(struct ssh *ssh)
2673 {
2674 	if (ssh->state && ssh->state->mux)
2675 		return ssh_packet_send_mux(ssh);
2676 	return ssh_packet_send2(ssh);
2677 }
2678 
2679 int
2680 sshpkt_disconnect(struct ssh *ssh, const char *fmt,...)
2681 {
2682 	char buf[1024];
2683 	va_list args;
2684 	int r;
2685 
2686 	va_start(args, fmt);
2687 	vsnprintf(buf, sizeof(buf), fmt, args);
2688 	va_end(args);
2689 
2690 	if ((r = sshpkt_start(ssh, SSH2_MSG_DISCONNECT)) != 0 ||
2691 	    (r = sshpkt_put_u32(ssh, SSH2_DISCONNECT_PROTOCOL_ERROR)) != 0 ||
2692 	    (r = sshpkt_put_cstring(ssh, buf)) != 0 ||
2693 	    (r = sshpkt_put_cstring(ssh, "")) != 0 ||
2694 	    (r = sshpkt_send(ssh)) != 0)
2695 		return r;
2696 	return 0;
2697 }
2698 
2699 /* roundup current message to pad bytes */
2700 int
2701 sshpkt_add_padding(struct ssh *ssh, u_char pad)
2702 {
2703 	ssh->state->extra_pad = pad;
2704 	return 0;
2705 }
2706