xref: /openssh-portable/packet.c (revision 7be8572b)
1 /* $OpenBSD: packet.c,v 1.281 2019/01/21 09:54:11 djm 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 #include <poll.h>
62 #include <signal.h>
63 #include <time.h>
64 
65 /*
66  * Explicitly include OpenSSL before zlib as some versions of OpenSSL have
67  * "free_func" in their headers, which zlib typedefs.
68  */
69 #ifdef WITH_OPENSSL
70 # include <openssl/bn.h>
71 # include <openssl/evp.h>
72 # ifdef OPENSSL_HAS_ECC
73 #  include <openssl/ec.h>
74 # endif
75 #endif
76 
77 #include <zlib.h>
78 
79 #include "xmalloc.h"
80 #include "crc32.h"
81 #include "compat.h"
82 #include "ssh2.h"
83 #include "cipher.h"
84 #include "sshkey.h"
85 #include "kex.h"
86 #include "digest.h"
87 #include "mac.h"
88 #include "log.h"
89 #include "canohost.h"
90 #include "misc.h"
91 #include "channels.h"
92 #include "ssh.h"
93 #include "packet.h"
94 #include "ssherr.h"
95 #include "sshbuf.h"
96 
97 #ifdef PACKET_DEBUG
98 #define DBG(x) x
99 #else
100 #define DBG(x)
101 #endif
102 
103 #define PACKET_MAX_SIZE (256 * 1024)
104 
105 struct packet_state {
106 	u_int32_t seqnr;
107 	u_int32_t packets;
108 	u_int64_t blocks;
109 	u_int64_t bytes;
110 };
111 
112 struct packet {
113 	TAILQ_ENTRY(packet) next;
114 	u_char type;
115 	struct sshbuf *payload;
116 };
117 
118 struct session_state {
119 	/*
120 	 * This variable contains the file descriptors used for
121 	 * communicating with the other side.  connection_in is used for
122 	 * reading; connection_out for writing.  These can be the same
123 	 * descriptor, in which case it is assumed to be a socket.
124 	 */
125 	int connection_in;
126 	int connection_out;
127 
128 	/* Protocol flags for the remote side. */
129 	u_int remote_protocol_flags;
130 
131 	/* Encryption context for receiving data.  Only used for decryption. */
132 	struct sshcipher_ctx *receive_context;
133 
134 	/* Encryption context for sending data.  Only used for encryption. */
135 	struct sshcipher_ctx *send_context;
136 
137 	/* Buffer for raw input data from the socket. */
138 	struct sshbuf *input;
139 
140 	/* Buffer for raw output data going to the socket. */
141 	struct sshbuf *output;
142 
143 	/* Buffer for the partial outgoing packet being constructed. */
144 	struct sshbuf *outgoing_packet;
145 
146 	/* Buffer for the incoming packet currently being processed. */
147 	struct sshbuf *incoming_packet;
148 
149 	/* Scratch buffer for packet compression/decompression. */
150 	struct sshbuf *compression_buffer;
151 
152 	/* Incoming/outgoing compression dictionaries */
153 	z_stream compression_in_stream;
154 	z_stream compression_out_stream;
155 	int compression_in_started;
156 	int compression_out_started;
157 	int compression_in_failures;
158 	int compression_out_failures;
159 
160 	/* default maximum packet size */
161 	u_int max_packet_size;
162 
163 	/* Flag indicating whether this module has been initialized. */
164 	int initialized;
165 
166 	/* Set to true if the connection is interactive. */
167 	int interactive_mode;
168 
169 	/* Set to true if we are the server side. */
170 	int server_side;
171 
172 	/* Set to true if we are authenticated. */
173 	int after_authentication;
174 
175 	int keep_alive_timeouts;
176 
177 	/* The maximum time that we will wait to send or receive a packet */
178 	int packet_timeout_ms;
179 
180 	/* Session key information for Encryption and MAC */
181 	struct newkeys *newkeys[MODE_MAX];
182 	struct packet_state p_read, p_send;
183 
184 	/* Volume-based rekeying */
185 	u_int64_t max_blocks_in, max_blocks_out, rekey_limit;
186 
187 	/* Time-based rekeying */
188 	u_int32_t rekey_interval;	/* how often in seconds */
189 	time_t rekey_time;	/* time of last rekeying */
190 
191 	/* roundup current message to extra_pad bytes */
192 	u_char extra_pad;
193 
194 	/* XXX discard incoming data after MAC error */
195 	u_int packet_discard;
196 	size_t packet_discard_mac_already;
197 	struct sshmac *packet_discard_mac;
198 
199 	/* Used in packet_read_poll2() */
200 	u_int packlen;
201 
202 	/* Used in packet_send2 */
203 	int rekeying;
204 
205 	/* Used in ssh_packet_send_mux() */
206 	int mux;
207 
208 	/* Used in packet_set_interactive */
209 	int set_interactive_called;
210 
211 	/* Used in packet_set_maxsize */
212 	int set_maxsize_called;
213 
214 	/* One-off warning about weak ciphers */
215 	int cipher_warning_done;
216 
217 	/* Hook for fuzzing inbound packets */
218 	ssh_packet_hook_fn *hook_in;
219 	void *hook_in_ctx;
220 
221 	TAILQ_HEAD(, packet) outgoing;
222 };
223 
224 struct ssh *
225 ssh_alloc_session_state(void)
226 {
227 	struct ssh *ssh = NULL;
228 	struct session_state *state = NULL;
229 
230 	if ((ssh = calloc(1, sizeof(*ssh))) == NULL ||
231 	    (state = calloc(1, sizeof(*state))) == NULL ||
232 	    (ssh->kex = kex_new()) == NULL ||
233 	    (state->input = sshbuf_new()) == NULL ||
234 	    (state->output = sshbuf_new()) == NULL ||
235 	    (state->outgoing_packet = sshbuf_new()) == NULL ||
236 	    (state->incoming_packet = sshbuf_new()) == NULL)
237 		goto fail;
238 	TAILQ_INIT(&state->outgoing);
239 	TAILQ_INIT(&ssh->private_keys);
240 	TAILQ_INIT(&ssh->public_keys);
241 	state->connection_in = -1;
242 	state->connection_out = -1;
243 	state->max_packet_size = 32768;
244 	state->packet_timeout_ms = -1;
245 	state->p_send.packets = state->p_read.packets = 0;
246 	state->initialized = 1;
247 	/*
248 	 * ssh_packet_send2() needs to queue packets until
249 	 * we've done the initial key exchange.
250 	 */
251 	state->rekeying = 1;
252 	ssh->state = state;
253 	return ssh;
254  fail:
255 	if (ssh) {
256 		kex_free(ssh->kex);
257 		free(ssh);
258 	}
259 	if (state) {
260 		sshbuf_free(state->input);
261 		sshbuf_free(state->output);
262 		sshbuf_free(state->incoming_packet);
263 		sshbuf_free(state->outgoing_packet);
264 		free(state);
265 	}
266 	return NULL;
267 }
268 
269 void
270 ssh_packet_set_input_hook(struct ssh *ssh, ssh_packet_hook_fn *hook, void *ctx)
271 {
272 	ssh->state->hook_in = hook;
273 	ssh->state->hook_in_ctx = ctx;
274 }
275 
276 /* Returns nonzero if rekeying is in progress */
277 int
278 ssh_packet_is_rekeying(struct ssh *ssh)
279 {
280 	return ssh->state->rekeying || ssh->kex->done == 0;
281 }
282 
283 /*
284  * Sets the descriptors used for communication.
285  */
286 struct ssh *
287 ssh_packet_set_connection(struct ssh *ssh, int fd_in, int fd_out)
288 {
289 	struct session_state *state;
290 	const struct sshcipher *none = cipher_by_name("none");
291 	int r;
292 
293 	if (none == NULL) {
294 		error("%s: cannot load cipher 'none'", __func__);
295 		return NULL;
296 	}
297 	if (ssh == NULL)
298 		ssh = ssh_alloc_session_state();
299 	if (ssh == NULL) {
300 		error("%s: cound not allocate state", __func__);
301 		return NULL;
302 	}
303 	state = ssh->state;
304 	state->connection_in = fd_in;
305 	state->connection_out = fd_out;
306 	if ((r = cipher_init(&state->send_context, none,
307 	    (const u_char *)"", 0, NULL, 0, CIPHER_ENCRYPT)) != 0 ||
308 	    (r = cipher_init(&state->receive_context, none,
309 	    (const u_char *)"", 0, NULL, 0, CIPHER_DECRYPT)) != 0) {
310 		error("%s: cipher_init failed: %s", __func__, ssh_err(r));
311 		free(ssh); /* XXX need ssh_free_session_state? */
312 		return NULL;
313 	}
314 	state->newkeys[MODE_IN] = state->newkeys[MODE_OUT] = NULL;
315 	/*
316 	 * Cache the IP address of the remote connection for use in error
317 	 * messages that might be generated after the connection has closed.
318 	 */
319 	(void)ssh_remote_ipaddr(ssh);
320 	return ssh;
321 }
322 
323 void
324 ssh_packet_set_timeout(struct ssh *ssh, int timeout, int count)
325 {
326 	struct session_state *state = ssh->state;
327 
328 	if (timeout <= 0 || count <= 0) {
329 		state->packet_timeout_ms = -1;
330 		return;
331 	}
332 	if ((INT_MAX / 1000) / count < timeout)
333 		state->packet_timeout_ms = INT_MAX;
334 	else
335 		state->packet_timeout_ms = timeout * count * 1000;
336 }
337 
338 void
339 ssh_packet_set_mux(struct ssh *ssh)
340 {
341 	ssh->state->mux = 1;
342 	ssh->state->rekeying = 0;
343 }
344 
345 int
346 ssh_packet_get_mux(struct ssh *ssh)
347 {
348 	return ssh->state->mux;
349 }
350 
351 int
352 ssh_packet_set_log_preamble(struct ssh *ssh, const char *fmt, ...)
353 {
354 	va_list args;
355 	int r;
356 
357 	free(ssh->log_preamble);
358 	if (fmt == NULL)
359 		ssh->log_preamble = NULL;
360 	else {
361 		va_start(args, fmt);
362 		r = vasprintf(&ssh->log_preamble, fmt, args);
363 		va_end(args);
364 		if (r < 0 || ssh->log_preamble == NULL)
365 			return SSH_ERR_ALLOC_FAIL;
366 	}
367 	return 0;
368 }
369 
370 int
371 ssh_packet_stop_discard(struct ssh *ssh)
372 {
373 	struct session_state *state = ssh->state;
374 	int r;
375 
376 	if (state->packet_discard_mac) {
377 		char buf[1024];
378 		size_t dlen = PACKET_MAX_SIZE;
379 
380 		if (dlen > state->packet_discard_mac_already)
381 			dlen -= state->packet_discard_mac_already;
382 		memset(buf, 'a', sizeof(buf));
383 		while (sshbuf_len(state->incoming_packet) < dlen)
384 			if ((r = sshbuf_put(state->incoming_packet, buf,
385 			    sizeof(buf))) != 0)
386 				return r;
387 		(void) mac_compute(state->packet_discard_mac,
388 		    state->p_read.seqnr,
389 		    sshbuf_ptr(state->incoming_packet), dlen,
390 		    NULL, 0);
391 	}
392 	logit("Finished discarding for %.200s port %d",
393 	    ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
394 	return SSH_ERR_MAC_INVALID;
395 }
396 
397 static int
398 ssh_packet_start_discard(struct ssh *ssh, struct sshenc *enc,
399     struct sshmac *mac, size_t mac_already, u_int discard)
400 {
401 	struct session_state *state = ssh->state;
402 	int r;
403 
404 	if (enc == NULL || !cipher_is_cbc(enc->cipher) || (mac && mac->etm)) {
405 		if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0)
406 			return r;
407 		return SSH_ERR_MAC_INVALID;
408 	}
409 	/*
410 	 * Record number of bytes over which the mac has already
411 	 * been computed in order to minimize timing attacks.
412 	 */
413 	if (mac && mac->enabled) {
414 		state->packet_discard_mac = mac;
415 		state->packet_discard_mac_already = mac_already;
416 	}
417 	if (sshbuf_len(state->input) >= discard)
418 		return ssh_packet_stop_discard(ssh);
419 	state->packet_discard = discard - sshbuf_len(state->input);
420 	return 0;
421 }
422 
423 /* Returns 1 if remote host is connected via socket, 0 if not. */
424 
425 int
426 ssh_packet_connection_is_on_socket(struct ssh *ssh)
427 {
428 	struct session_state *state;
429 	struct sockaddr_storage from, to;
430 	socklen_t fromlen, tolen;
431 
432 	if (ssh == NULL || ssh->state == NULL)
433 		return 0;
434 
435 	state = ssh->state;
436 	if (state->connection_in == -1 || state->connection_out == -1)
437 		return 0;
438 	/* filedescriptors in and out are the same, so it's a socket */
439 	if (state->connection_in == state->connection_out)
440 		return 1;
441 	fromlen = sizeof(from);
442 	memset(&from, 0, sizeof(from));
443 	if (getpeername(state->connection_in, (struct sockaddr *)&from,
444 	    &fromlen) < 0)
445 		return 0;
446 	tolen = sizeof(to);
447 	memset(&to, 0, sizeof(to));
448 	if (getpeername(state->connection_out, (struct sockaddr *)&to,
449 	    &tolen) < 0)
450 		return 0;
451 	if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0)
452 		return 0;
453 	if (from.ss_family != AF_INET && from.ss_family != AF_INET6)
454 		return 0;
455 	return 1;
456 }
457 
458 void
459 ssh_packet_get_bytes(struct ssh *ssh, u_int64_t *ibytes, u_int64_t *obytes)
460 {
461 	if (ibytes)
462 		*ibytes = ssh->state->p_read.bytes;
463 	if (obytes)
464 		*obytes = ssh->state->p_send.bytes;
465 }
466 
467 int
468 ssh_packet_connection_af(struct ssh *ssh)
469 {
470 	struct sockaddr_storage to;
471 	socklen_t tolen = sizeof(to);
472 
473 	memset(&to, 0, sizeof(to));
474 	if (getsockname(ssh->state->connection_out, (struct sockaddr *)&to,
475 	    &tolen) < 0)
476 		return 0;
477 #ifdef IPV4_IN_IPV6
478 	if (to.ss_family == AF_INET6 &&
479 	    IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)&to)->sin6_addr))
480 		return AF_INET;
481 #endif
482 	return to.ss_family;
483 }
484 
485 /* Sets the connection into non-blocking mode. */
486 
487 void
488 ssh_packet_set_nonblocking(struct ssh *ssh)
489 {
490 	/* Set the socket into non-blocking mode. */
491 	set_nonblock(ssh->state->connection_in);
492 
493 	if (ssh->state->connection_out != ssh->state->connection_in)
494 		set_nonblock(ssh->state->connection_out);
495 }
496 
497 /* Returns the socket used for reading. */
498 
499 int
500 ssh_packet_get_connection_in(struct ssh *ssh)
501 {
502 	return ssh->state->connection_in;
503 }
504 
505 /* Returns the descriptor used for writing. */
506 
507 int
508 ssh_packet_get_connection_out(struct ssh *ssh)
509 {
510 	return ssh->state->connection_out;
511 }
512 
513 /*
514  * Returns the IP-address of the remote host as a string.  The returned
515  * string must not be freed.
516  */
517 
518 const char *
519 ssh_remote_ipaddr(struct ssh *ssh)
520 {
521 	int sock;
522 
523 	/* Check whether we have cached the ipaddr. */
524 	if (ssh->remote_ipaddr == NULL) {
525 		if (ssh_packet_connection_is_on_socket(ssh)) {
526 			sock = ssh->state->connection_in;
527 			ssh->remote_ipaddr = get_peer_ipaddr(sock);
528 			ssh->remote_port = get_peer_port(sock);
529 			ssh->local_ipaddr = get_local_ipaddr(sock);
530 			ssh->local_port = get_local_port(sock);
531 		} else {
532 			ssh->remote_ipaddr = strdup("UNKNOWN");
533 			ssh->remote_port = 65535;
534 			ssh->local_ipaddr = strdup("UNKNOWN");
535 			ssh->local_port = 65535;
536 		}
537 	}
538 	return ssh->remote_ipaddr;
539 }
540 
541 /* Returns the port number of the remote host. */
542 
543 int
544 ssh_remote_port(struct ssh *ssh)
545 {
546 	(void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */
547 	return ssh->remote_port;
548 }
549 
550 /*
551  * Returns the IP-address of the local host as a string.  The returned
552  * string must not be freed.
553  */
554 
555 const char *
556 ssh_local_ipaddr(struct ssh *ssh)
557 {
558 	(void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */
559 	return ssh->local_ipaddr;
560 }
561 
562 /* Returns the port number of the local host. */
563 
564 int
565 ssh_local_port(struct ssh *ssh)
566 {
567 	(void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */
568 	return ssh->local_port;
569 }
570 
571 /* Returns the routing domain of the input socket, or NULL if unavailable */
572 const char *
573 ssh_packet_rdomain_in(struct ssh *ssh)
574 {
575 	if (ssh->rdomain_in != NULL)
576 		return ssh->rdomain_in;
577 	if (!ssh_packet_connection_is_on_socket(ssh))
578 		return NULL;
579 	ssh->rdomain_in = get_rdomain(ssh->state->connection_in);
580 	return ssh->rdomain_in;
581 }
582 
583 /* Closes the connection and clears and frees internal data structures. */
584 
585 static void
586 ssh_packet_close_internal(struct ssh *ssh, int do_close)
587 {
588 	struct session_state *state = ssh->state;
589 	u_int mode;
590 
591 	if (!state->initialized)
592 		return;
593 	state->initialized = 0;
594 	if (do_close) {
595 		if (state->connection_in == state->connection_out) {
596 			close(state->connection_out);
597 		} else {
598 			close(state->connection_in);
599 			close(state->connection_out);
600 		}
601 	}
602 	sshbuf_free(state->input);
603 	sshbuf_free(state->output);
604 	sshbuf_free(state->outgoing_packet);
605 	sshbuf_free(state->incoming_packet);
606 	for (mode = 0; mode < MODE_MAX; mode++) {
607 		kex_free_newkeys(state->newkeys[mode]);	/* current keys */
608 		state->newkeys[mode] = NULL;
609 		ssh_clear_newkeys(ssh, mode);		/* next keys */
610 	}
611 	/* compression state is in shared mem, so we can only release it once */
612 	if (do_close && state->compression_buffer) {
613 		sshbuf_free(state->compression_buffer);
614 		if (state->compression_out_started) {
615 			z_streamp stream = &state->compression_out_stream;
616 			debug("compress outgoing: "
617 			    "raw data %llu, compressed %llu, factor %.2f",
618 				(unsigned long long)stream->total_in,
619 				(unsigned long long)stream->total_out,
620 				stream->total_in == 0 ? 0.0 :
621 				(double) stream->total_out / stream->total_in);
622 			if (state->compression_out_failures == 0)
623 				deflateEnd(stream);
624 		}
625 		if (state->compression_in_started) {
626 			z_streamp stream = &state->compression_in_stream;
627 			debug("compress incoming: "
628 			    "raw data %llu, compressed %llu, factor %.2f",
629 			    (unsigned long long)stream->total_out,
630 			    (unsigned long long)stream->total_in,
631 			    stream->total_out == 0 ? 0.0 :
632 			    (double) stream->total_in / stream->total_out);
633 			if (state->compression_in_failures == 0)
634 				inflateEnd(stream);
635 		}
636 	}
637 	cipher_free(state->send_context);
638 	cipher_free(state->receive_context);
639 	state->send_context = state->receive_context = NULL;
640 	if (do_close) {
641 		free(ssh->local_ipaddr);
642 		ssh->local_ipaddr = NULL;
643 		free(ssh->remote_ipaddr);
644 		ssh->remote_ipaddr = NULL;
645 		free(ssh->state);
646 		ssh->state = NULL;
647 	}
648 }
649 
650 void
651 ssh_packet_close(struct ssh *ssh)
652 {
653 	ssh_packet_close_internal(ssh, 1);
654 }
655 
656 void
657 ssh_packet_clear_keys(struct ssh *ssh)
658 {
659 	ssh_packet_close_internal(ssh, 0);
660 }
661 
662 /* Sets remote side protocol flags. */
663 
664 void
665 ssh_packet_set_protocol_flags(struct ssh *ssh, u_int protocol_flags)
666 {
667 	ssh->state->remote_protocol_flags = protocol_flags;
668 }
669 
670 /* Returns the remote protocol flags set earlier by the above function. */
671 
672 u_int
673 ssh_packet_get_protocol_flags(struct ssh *ssh)
674 {
675 	return ssh->state->remote_protocol_flags;
676 }
677 
678 /*
679  * Starts packet compression from the next packet on in both directions.
680  * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip.
681  */
682 
683 static int
684 ssh_packet_init_compression(struct ssh *ssh)
685 {
686 	if (!ssh->state->compression_buffer &&
687 	   ((ssh->state->compression_buffer = sshbuf_new()) == NULL))
688 		return SSH_ERR_ALLOC_FAIL;
689 	return 0;
690 }
691 
692 static int
693 start_compression_out(struct ssh *ssh, int level)
694 {
695 	if (level < 1 || level > 9)
696 		return SSH_ERR_INVALID_ARGUMENT;
697 	debug("Enabling compression at level %d.", level);
698 	if (ssh->state->compression_out_started == 1)
699 		deflateEnd(&ssh->state->compression_out_stream);
700 	switch (deflateInit(&ssh->state->compression_out_stream, level)) {
701 	case Z_OK:
702 		ssh->state->compression_out_started = 1;
703 		break;
704 	case Z_MEM_ERROR:
705 		return SSH_ERR_ALLOC_FAIL;
706 	default:
707 		return SSH_ERR_INTERNAL_ERROR;
708 	}
709 	return 0;
710 }
711 
712 static int
713 start_compression_in(struct ssh *ssh)
714 {
715 	if (ssh->state->compression_in_started == 1)
716 		inflateEnd(&ssh->state->compression_in_stream);
717 	switch (inflateInit(&ssh->state->compression_in_stream)) {
718 	case Z_OK:
719 		ssh->state->compression_in_started = 1;
720 		break;
721 	case Z_MEM_ERROR:
722 		return SSH_ERR_ALLOC_FAIL;
723 	default:
724 		return SSH_ERR_INTERNAL_ERROR;
725 	}
726 	return 0;
727 }
728 
729 /* XXX remove need for separate compression buffer */
730 static int
731 compress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out)
732 {
733 	u_char buf[4096];
734 	int r, status;
735 
736 	if (ssh->state->compression_out_started != 1)
737 		return SSH_ERR_INTERNAL_ERROR;
738 
739 	/* This case is not handled below. */
740 	if (sshbuf_len(in) == 0)
741 		return 0;
742 
743 	/* Input is the contents of the input buffer. */
744 	if ((ssh->state->compression_out_stream.next_in =
745 	    sshbuf_mutable_ptr(in)) == NULL)
746 		return SSH_ERR_INTERNAL_ERROR;
747 	ssh->state->compression_out_stream.avail_in = sshbuf_len(in);
748 
749 	/* Loop compressing until deflate() returns with avail_out != 0. */
750 	do {
751 		/* Set up fixed-size output buffer. */
752 		ssh->state->compression_out_stream.next_out = buf;
753 		ssh->state->compression_out_stream.avail_out = sizeof(buf);
754 
755 		/* Compress as much data into the buffer as possible. */
756 		status = deflate(&ssh->state->compression_out_stream,
757 		    Z_PARTIAL_FLUSH);
758 		switch (status) {
759 		case Z_MEM_ERROR:
760 			return SSH_ERR_ALLOC_FAIL;
761 		case Z_OK:
762 			/* Append compressed data to output_buffer. */
763 			if ((r = sshbuf_put(out, buf, sizeof(buf) -
764 			    ssh->state->compression_out_stream.avail_out)) != 0)
765 				return r;
766 			break;
767 		case Z_STREAM_ERROR:
768 		default:
769 			ssh->state->compression_out_failures++;
770 			return SSH_ERR_INVALID_FORMAT;
771 		}
772 	} while (ssh->state->compression_out_stream.avail_out == 0);
773 	return 0;
774 }
775 
776 static int
777 uncompress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out)
778 {
779 	u_char buf[4096];
780 	int r, status;
781 
782 	if (ssh->state->compression_in_started != 1)
783 		return SSH_ERR_INTERNAL_ERROR;
784 
785 	if ((ssh->state->compression_in_stream.next_in =
786 	    sshbuf_mutable_ptr(in)) == NULL)
787 		return SSH_ERR_INTERNAL_ERROR;
788 	ssh->state->compression_in_stream.avail_in = sshbuf_len(in);
789 
790 	for (;;) {
791 		/* Set up fixed-size output buffer. */
792 		ssh->state->compression_in_stream.next_out = buf;
793 		ssh->state->compression_in_stream.avail_out = sizeof(buf);
794 
795 		status = inflate(&ssh->state->compression_in_stream,
796 		    Z_PARTIAL_FLUSH);
797 		switch (status) {
798 		case Z_OK:
799 			if ((r = sshbuf_put(out, buf, sizeof(buf) -
800 			    ssh->state->compression_in_stream.avail_out)) != 0)
801 				return r;
802 			break;
803 		case Z_BUF_ERROR:
804 			/*
805 			 * Comments in zlib.h say that we should keep calling
806 			 * inflate() until we get an error.  This appears to
807 			 * be the error that we get.
808 			 */
809 			return 0;
810 		case Z_DATA_ERROR:
811 			return SSH_ERR_INVALID_FORMAT;
812 		case Z_MEM_ERROR:
813 			return SSH_ERR_ALLOC_FAIL;
814 		case Z_STREAM_ERROR:
815 		default:
816 			ssh->state->compression_in_failures++;
817 			return SSH_ERR_INTERNAL_ERROR;
818 		}
819 	}
820 	/* NOTREACHED */
821 }
822 
823 void
824 ssh_clear_newkeys(struct ssh *ssh, int mode)
825 {
826 	if (ssh->kex && ssh->kex->newkeys[mode]) {
827 		kex_free_newkeys(ssh->kex->newkeys[mode]);
828 		ssh->kex->newkeys[mode] = NULL;
829 	}
830 }
831 
832 int
833 ssh_set_newkeys(struct ssh *ssh, int mode)
834 {
835 	struct session_state *state = ssh->state;
836 	struct sshenc *enc;
837 	struct sshmac *mac;
838 	struct sshcomp *comp;
839 	struct sshcipher_ctx **ccp;
840 	struct packet_state *ps;
841 	u_int64_t *max_blocks;
842 	const char *wmsg;
843 	int r, crypt_type;
844 
845 	debug2("set_newkeys: mode %d", mode);
846 
847 	if (mode == MODE_OUT) {
848 		ccp = &state->send_context;
849 		crypt_type = CIPHER_ENCRYPT;
850 		ps = &state->p_send;
851 		max_blocks = &state->max_blocks_out;
852 	} else {
853 		ccp = &state->receive_context;
854 		crypt_type = CIPHER_DECRYPT;
855 		ps = &state->p_read;
856 		max_blocks = &state->max_blocks_in;
857 	}
858 	if (state->newkeys[mode] != NULL) {
859 		debug("set_newkeys: rekeying, input %llu bytes %llu blocks, "
860 		   "output %llu bytes %llu blocks",
861 		   (unsigned long long)state->p_read.bytes,
862 		   (unsigned long long)state->p_read.blocks,
863 		   (unsigned long long)state->p_send.bytes,
864 		   (unsigned long long)state->p_send.blocks);
865 		kex_free_newkeys(state->newkeys[mode]);
866 		state->newkeys[mode] = NULL;
867 	}
868 	/* note that both bytes and the seqnr are not reset */
869 	ps->packets = ps->blocks = 0;
870 	/* move newkeys from kex to state */
871 	if ((state->newkeys[mode] = ssh->kex->newkeys[mode]) == NULL)
872 		return SSH_ERR_INTERNAL_ERROR;
873 	ssh->kex->newkeys[mode] = NULL;
874 	enc  = &state->newkeys[mode]->enc;
875 	mac  = &state->newkeys[mode]->mac;
876 	comp = &state->newkeys[mode]->comp;
877 	if (cipher_authlen(enc->cipher) == 0) {
878 		if ((r = mac_init(mac)) != 0)
879 			return r;
880 	}
881 	mac->enabled = 1;
882 	DBG(debug("cipher_init_context: %d", mode));
883 	cipher_free(*ccp);
884 	*ccp = NULL;
885 	if ((r = cipher_init(ccp, enc->cipher, enc->key, enc->key_len,
886 	    enc->iv, enc->iv_len, crypt_type)) != 0)
887 		return r;
888 	if (!state->cipher_warning_done &&
889 	    (wmsg = cipher_warning_message(*ccp)) != NULL) {
890 		error("Warning: %s", wmsg);
891 		state->cipher_warning_done = 1;
892 	}
893 	/* Deleting the keys does not gain extra security */
894 	/* explicit_bzero(enc->iv,  enc->block_size);
895 	   explicit_bzero(enc->key, enc->key_len);
896 	   explicit_bzero(mac->key, mac->key_len); */
897 	if ((comp->type == COMP_ZLIB ||
898 	    (comp->type == COMP_DELAYED &&
899 	     state->after_authentication)) && comp->enabled == 0) {
900 		if ((r = ssh_packet_init_compression(ssh)) < 0)
901 			return r;
902 		if (mode == MODE_OUT) {
903 			if ((r = start_compression_out(ssh, 6)) != 0)
904 				return r;
905 		} else {
906 			if ((r = start_compression_in(ssh)) != 0)
907 				return r;
908 		}
909 		comp->enabled = 1;
910 	}
911 	/*
912 	 * The 2^(blocksize*2) limit is too expensive for 3DES,
913 	 * so enforce a 1GB limit for small blocksizes.
914 	 * See RFC4344 section 3.2.
915 	 */
916 	if (enc->block_size >= 16)
917 		*max_blocks = (u_int64_t)1 << (enc->block_size*2);
918 	else
919 		*max_blocks = ((u_int64_t)1 << 30) / enc->block_size;
920 	if (state->rekey_limit)
921 		*max_blocks = MINIMUM(*max_blocks,
922 		    state->rekey_limit / enc->block_size);
923 	debug("rekey after %llu blocks", (unsigned long long)*max_blocks);
924 	return 0;
925 }
926 
927 #define MAX_PACKETS	(1U<<31)
928 static int
929 ssh_packet_need_rekeying(struct ssh *ssh, u_int outbound_packet_len)
930 {
931 	struct session_state *state = ssh->state;
932 	u_int32_t out_blocks;
933 
934 	/* XXX client can't cope with rekeying pre-auth */
935 	if (!state->after_authentication)
936 		return 0;
937 
938 	/* Haven't keyed yet or KEX in progress. */
939 	if (ssh_packet_is_rekeying(ssh))
940 		return 0;
941 
942 	/* Peer can't rekey */
943 	if (ssh->compat & SSH_BUG_NOREKEY)
944 		return 0;
945 
946 	/*
947 	 * Permit one packet in or out per rekey - this allows us to
948 	 * make progress when rekey limits are very small.
949 	 */
950 	if (state->p_send.packets == 0 && state->p_read.packets == 0)
951 		return 0;
952 
953 	/* Time-based rekeying */
954 	if (state->rekey_interval != 0 &&
955 	    (int64_t)state->rekey_time + state->rekey_interval <= monotime())
956 		return 1;
957 
958 	/*
959 	 * Always rekey when MAX_PACKETS sent in either direction
960 	 * As per RFC4344 section 3.1 we do this after 2^31 packets.
961 	 */
962 	if (state->p_send.packets > MAX_PACKETS ||
963 	    state->p_read.packets > MAX_PACKETS)
964 		return 1;
965 
966 	/* Rekey after (cipher-specific) maximum blocks */
967 	out_blocks = ROUNDUP(outbound_packet_len,
968 	    state->newkeys[MODE_OUT]->enc.block_size);
969 	return (state->max_blocks_out &&
970 	    (state->p_send.blocks + out_blocks > state->max_blocks_out)) ||
971 	    (state->max_blocks_in &&
972 	    (state->p_read.blocks > state->max_blocks_in));
973 }
974 
975 /*
976  * Delayed compression for SSH2 is enabled after authentication:
977  * This happens on the server side after a SSH2_MSG_USERAUTH_SUCCESS is sent,
978  * and on the client side after a SSH2_MSG_USERAUTH_SUCCESS is received.
979  */
980 static int
981 ssh_packet_enable_delayed_compress(struct ssh *ssh)
982 {
983 	struct session_state *state = ssh->state;
984 	struct sshcomp *comp = NULL;
985 	int r, mode;
986 
987 	/*
988 	 * Remember that we are past the authentication step, so rekeying
989 	 * with COMP_DELAYED will turn on compression immediately.
990 	 */
991 	state->after_authentication = 1;
992 	for (mode = 0; mode < MODE_MAX; mode++) {
993 		/* protocol error: USERAUTH_SUCCESS received before NEWKEYS */
994 		if (state->newkeys[mode] == NULL)
995 			continue;
996 		comp = &state->newkeys[mode]->comp;
997 		if (comp && !comp->enabled && comp->type == COMP_DELAYED) {
998 			if ((r = ssh_packet_init_compression(ssh)) != 0)
999 				return r;
1000 			if (mode == MODE_OUT) {
1001 				if ((r = start_compression_out(ssh, 6)) != 0)
1002 					return r;
1003 			} else {
1004 				if ((r = start_compression_in(ssh)) != 0)
1005 					return r;
1006 			}
1007 			comp->enabled = 1;
1008 		}
1009 	}
1010 	return 0;
1011 }
1012 
1013 /* Used to mute debug logging for noisy packet types */
1014 int
1015 ssh_packet_log_type(u_char type)
1016 {
1017 	switch (type) {
1018 	case SSH2_MSG_CHANNEL_DATA:
1019 	case SSH2_MSG_CHANNEL_EXTENDED_DATA:
1020 	case SSH2_MSG_CHANNEL_WINDOW_ADJUST:
1021 		return 0;
1022 	default:
1023 		return 1;
1024 	}
1025 }
1026 
1027 /*
1028  * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue)
1029  */
1030 int
1031 ssh_packet_send2_wrapped(struct ssh *ssh)
1032 {
1033 	struct session_state *state = ssh->state;
1034 	u_char type, *cp, macbuf[SSH_DIGEST_MAX_LENGTH];
1035 	u_char tmp, padlen, pad = 0;
1036 	u_int authlen = 0, aadlen = 0;
1037 	u_int len;
1038 	struct sshenc *enc   = NULL;
1039 	struct sshmac *mac   = NULL;
1040 	struct sshcomp *comp = NULL;
1041 	int r, block_size;
1042 
1043 	if (state->newkeys[MODE_OUT] != NULL) {
1044 		enc  = &state->newkeys[MODE_OUT]->enc;
1045 		mac  = &state->newkeys[MODE_OUT]->mac;
1046 		comp = &state->newkeys[MODE_OUT]->comp;
1047 		/* disable mac for authenticated encryption */
1048 		if ((authlen = cipher_authlen(enc->cipher)) != 0)
1049 			mac = NULL;
1050 	}
1051 	block_size = enc ? enc->block_size : 8;
1052 	aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0;
1053 
1054 	type = (sshbuf_ptr(state->outgoing_packet))[5];
1055 	if (ssh_packet_log_type(type))
1056 		debug3("send packet: type %u", type);
1057 #ifdef PACKET_DEBUG
1058 	fprintf(stderr, "plain:     ");
1059 	sshbuf_dump(state->outgoing_packet, stderr);
1060 #endif
1061 
1062 	if (comp && comp->enabled) {
1063 		len = sshbuf_len(state->outgoing_packet);
1064 		/* skip header, compress only payload */
1065 		if ((r = sshbuf_consume(state->outgoing_packet, 5)) != 0)
1066 			goto out;
1067 		sshbuf_reset(state->compression_buffer);
1068 		if ((r = compress_buffer(ssh, state->outgoing_packet,
1069 		    state->compression_buffer)) != 0)
1070 			goto out;
1071 		sshbuf_reset(state->outgoing_packet);
1072 		if ((r = sshbuf_put(state->outgoing_packet,
1073 		    "\0\0\0\0\0", 5)) != 0 ||
1074 		    (r = sshbuf_putb(state->outgoing_packet,
1075 		    state->compression_buffer)) != 0)
1076 			goto out;
1077 		DBG(debug("compression: raw %d compressed %zd", len,
1078 		    sshbuf_len(state->outgoing_packet)));
1079 	}
1080 
1081 	/* sizeof (packet_len + pad_len + payload) */
1082 	len = sshbuf_len(state->outgoing_packet);
1083 
1084 	/*
1085 	 * calc size of padding, alloc space, get random data,
1086 	 * minimum padding is 4 bytes
1087 	 */
1088 	len -= aadlen; /* packet length is not encrypted for EtM modes */
1089 	padlen = block_size - (len % block_size);
1090 	if (padlen < 4)
1091 		padlen += block_size;
1092 	if (state->extra_pad) {
1093 		tmp = state->extra_pad;
1094 		state->extra_pad =
1095 		    ROUNDUP(state->extra_pad, block_size);
1096 		/* check if roundup overflowed */
1097 		if (state->extra_pad < tmp)
1098 			return SSH_ERR_INVALID_ARGUMENT;
1099 		tmp = (len + padlen) % state->extra_pad;
1100 		/* Check whether pad calculation below will underflow */
1101 		if (tmp > state->extra_pad)
1102 			return SSH_ERR_INVALID_ARGUMENT;
1103 		pad = state->extra_pad - tmp;
1104 		DBG(debug3("%s: adding %d (len %d padlen %d extra_pad %d)",
1105 		    __func__, pad, len, padlen, state->extra_pad));
1106 		tmp = padlen;
1107 		padlen += pad;
1108 		/* Check whether padlen calculation overflowed */
1109 		if (padlen < tmp)
1110 			return SSH_ERR_INVALID_ARGUMENT; /* overflow */
1111 		state->extra_pad = 0;
1112 	}
1113 	if ((r = sshbuf_reserve(state->outgoing_packet, padlen, &cp)) != 0)
1114 		goto out;
1115 	if (enc && !cipher_ctx_is_plaintext(state->send_context)) {
1116 		/* random padding */
1117 		arc4random_buf(cp, padlen);
1118 	} else {
1119 		/* clear padding */
1120 		explicit_bzero(cp, padlen);
1121 	}
1122 	/* sizeof (packet_len + pad_len + payload + padding) */
1123 	len = sshbuf_len(state->outgoing_packet);
1124 	cp = sshbuf_mutable_ptr(state->outgoing_packet);
1125 	if (cp == NULL) {
1126 		r = SSH_ERR_INTERNAL_ERROR;
1127 		goto out;
1128 	}
1129 	/* packet_length includes payload, padding and padding length field */
1130 	POKE_U32(cp, len - 4);
1131 	cp[4] = padlen;
1132 	DBG(debug("send: len %d (includes padlen %d, aadlen %d)",
1133 	    len, padlen, aadlen));
1134 
1135 	/* compute MAC over seqnr and packet(length fields, payload, padding) */
1136 	if (mac && mac->enabled && !mac->etm) {
1137 		if ((r = mac_compute(mac, state->p_send.seqnr,
1138 		    sshbuf_ptr(state->outgoing_packet), len,
1139 		    macbuf, sizeof(macbuf))) != 0)
1140 			goto out;
1141 		DBG(debug("done calc MAC out #%d", state->p_send.seqnr));
1142 	}
1143 	/* encrypt packet and append to output buffer. */
1144 	if ((r = sshbuf_reserve(state->output,
1145 	    sshbuf_len(state->outgoing_packet) + authlen, &cp)) != 0)
1146 		goto out;
1147 	if ((r = cipher_crypt(state->send_context, state->p_send.seqnr, cp,
1148 	    sshbuf_ptr(state->outgoing_packet),
1149 	    len - aadlen, aadlen, authlen)) != 0)
1150 		goto out;
1151 	/* append unencrypted MAC */
1152 	if (mac && mac->enabled) {
1153 		if (mac->etm) {
1154 			/* EtM: compute mac over aadlen + cipher text */
1155 			if ((r = mac_compute(mac, state->p_send.seqnr,
1156 			    cp, len, macbuf, sizeof(macbuf))) != 0)
1157 				goto out;
1158 			DBG(debug("done calc MAC(EtM) out #%d",
1159 			    state->p_send.seqnr));
1160 		}
1161 		if ((r = sshbuf_put(state->output, macbuf, mac->mac_len)) != 0)
1162 			goto out;
1163 	}
1164 #ifdef PACKET_DEBUG
1165 	fprintf(stderr, "encrypted: ");
1166 	sshbuf_dump(state->output, stderr);
1167 #endif
1168 	/* increment sequence number for outgoing packets */
1169 	if (++state->p_send.seqnr == 0)
1170 		logit("outgoing seqnr wraps around");
1171 	if (++state->p_send.packets == 0)
1172 		if (!(ssh->compat & SSH_BUG_NOREKEY))
1173 			return SSH_ERR_NEED_REKEY;
1174 	state->p_send.blocks += len / block_size;
1175 	state->p_send.bytes += len;
1176 	sshbuf_reset(state->outgoing_packet);
1177 
1178 	if (type == SSH2_MSG_NEWKEYS)
1179 		r = ssh_set_newkeys(ssh, MODE_OUT);
1180 	else if (type == SSH2_MSG_USERAUTH_SUCCESS && state->server_side)
1181 		r = ssh_packet_enable_delayed_compress(ssh);
1182 	else
1183 		r = 0;
1184  out:
1185 	return r;
1186 }
1187 
1188 /* returns non-zero if the specified packet type is usec by KEX */
1189 static int
1190 ssh_packet_type_is_kex(u_char type)
1191 {
1192 	return
1193 	    type >= SSH2_MSG_TRANSPORT_MIN &&
1194 	    type <= SSH2_MSG_TRANSPORT_MAX &&
1195 	    type != SSH2_MSG_SERVICE_REQUEST &&
1196 	    type != SSH2_MSG_SERVICE_ACCEPT &&
1197 	    type != SSH2_MSG_EXT_INFO;
1198 }
1199 
1200 int
1201 ssh_packet_send2(struct ssh *ssh)
1202 {
1203 	struct session_state *state = ssh->state;
1204 	struct packet *p;
1205 	u_char type;
1206 	int r, need_rekey;
1207 
1208 	if (sshbuf_len(state->outgoing_packet) < 6)
1209 		return SSH_ERR_INTERNAL_ERROR;
1210 	type = sshbuf_ptr(state->outgoing_packet)[5];
1211 	need_rekey = !ssh_packet_type_is_kex(type) &&
1212 	    ssh_packet_need_rekeying(ssh, sshbuf_len(state->outgoing_packet));
1213 
1214 	/*
1215 	 * During rekeying we can only send key exchange messages.
1216 	 * Queue everything else.
1217 	 */
1218 	if ((need_rekey || state->rekeying) && !ssh_packet_type_is_kex(type)) {
1219 		if (need_rekey)
1220 			debug3("%s: rekex triggered", __func__);
1221 		debug("enqueue packet: %u", type);
1222 		p = calloc(1, sizeof(*p));
1223 		if (p == NULL)
1224 			return SSH_ERR_ALLOC_FAIL;
1225 		p->type = type;
1226 		p->payload = state->outgoing_packet;
1227 		TAILQ_INSERT_TAIL(&state->outgoing, p, next);
1228 		state->outgoing_packet = sshbuf_new();
1229 		if (state->outgoing_packet == NULL)
1230 			return SSH_ERR_ALLOC_FAIL;
1231 		if (need_rekey) {
1232 			/*
1233 			 * This packet triggered a rekey, so send the
1234 			 * KEXINIT now.
1235 			 * NB. reenters this function via kex_start_rekex().
1236 			 */
1237 			return kex_start_rekex(ssh);
1238 		}
1239 		return 0;
1240 	}
1241 
1242 	/* rekeying starts with sending KEXINIT */
1243 	if (type == SSH2_MSG_KEXINIT)
1244 		state->rekeying = 1;
1245 
1246 	if ((r = ssh_packet_send2_wrapped(ssh)) != 0)
1247 		return r;
1248 
1249 	/* after a NEWKEYS message we can send the complete queue */
1250 	if (type == SSH2_MSG_NEWKEYS) {
1251 		state->rekeying = 0;
1252 		state->rekey_time = monotime();
1253 		while ((p = TAILQ_FIRST(&state->outgoing))) {
1254 			type = p->type;
1255 			/*
1256 			 * If this packet triggers a rekex, then skip the
1257 			 * remaining packets in the queue for now.
1258 			 * NB. re-enters this function via kex_start_rekex.
1259 			 */
1260 			if (ssh_packet_need_rekeying(ssh,
1261 			    sshbuf_len(p->payload))) {
1262 				debug3("%s: queued packet triggered rekex",
1263 				    __func__);
1264 				return kex_start_rekex(ssh);
1265 			}
1266 			debug("dequeue packet: %u", type);
1267 			sshbuf_free(state->outgoing_packet);
1268 			state->outgoing_packet = p->payload;
1269 			TAILQ_REMOVE(&state->outgoing, p, next);
1270 			memset(p, 0, sizeof(*p));
1271 			free(p);
1272 			if ((r = ssh_packet_send2_wrapped(ssh)) != 0)
1273 				return r;
1274 		}
1275 	}
1276 	return 0;
1277 }
1278 
1279 /*
1280  * Waits until a packet has been received, and returns its type.  Note that
1281  * no other data is processed until this returns, so this function should not
1282  * be used during the interactive session.
1283  */
1284 
1285 int
1286 ssh_packet_read_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
1287 {
1288 	struct session_state *state = ssh->state;
1289 	int len, r, ms_remain;
1290 	fd_set *setp;
1291 	char buf[8192];
1292 	struct timeval timeout, start, *timeoutp = NULL;
1293 
1294 	DBG(debug("packet_read()"));
1295 
1296 	setp = calloc(howmany(state->connection_in + 1,
1297 	    NFDBITS), sizeof(fd_mask));
1298 	if (setp == NULL)
1299 		return SSH_ERR_ALLOC_FAIL;
1300 
1301 	/*
1302 	 * Since we are blocking, ensure that all written packets have
1303 	 * been sent.
1304 	 */
1305 	if ((r = ssh_packet_write_wait(ssh)) != 0)
1306 		goto out;
1307 
1308 	/* Stay in the loop until we have received a complete packet. */
1309 	for (;;) {
1310 		/* Try to read a packet from the buffer. */
1311 		r = ssh_packet_read_poll_seqnr(ssh, typep, seqnr_p);
1312 		if (r != 0)
1313 			break;
1314 		/* If we got a packet, return it. */
1315 		if (*typep != SSH_MSG_NONE)
1316 			break;
1317 		/*
1318 		 * Otherwise, wait for some data to arrive, add it to the
1319 		 * buffer, and try again.
1320 		 */
1321 		memset(setp, 0, howmany(state->connection_in + 1,
1322 		    NFDBITS) * sizeof(fd_mask));
1323 		FD_SET(state->connection_in, setp);
1324 
1325 		if (state->packet_timeout_ms > 0) {
1326 			ms_remain = state->packet_timeout_ms;
1327 			timeoutp = &timeout;
1328 		}
1329 		/* Wait for some data to arrive. */
1330 		for (;;) {
1331 			if (state->packet_timeout_ms != -1) {
1332 				ms_to_timeval(&timeout, ms_remain);
1333 				monotime_tv(&start);
1334 			}
1335 			if ((r = select(state->connection_in + 1, setp,
1336 			    NULL, NULL, timeoutp)) >= 0)
1337 				break;
1338 			if (errno != EAGAIN && errno != EINTR &&
1339 			    errno != EWOULDBLOCK) {
1340 				r = SSH_ERR_SYSTEM_ERROR;
1341 				goto out;
1342 			}
1343 			if (state->packet_timeout_ms == -1)
1344 				continue;
1345 			ms_subtract_diff(&start, &ms_remain);
1346 			if (ms_remain <= 0) {
1347 				r = 0;
1348 				break;
1349 			}
1350 		}
1351 		if (r == 0) {
1352 			r = SSH_ERR_CONN_TIMEOUT;
1353 			goto out;
1354 		}
1355 		/* Read data from the socket. */
1356 		len = read(state->connection_in, buf, sizeof(buf));
1357 		if (len == 0) {
1358 			r = SSH_ERR_CONN_CLOSED;
1359 			goto out;
1360 		}
1361 		if (len < 0) {
1362 			r = SSH_ERR_SYSTEM_ERROR;
1363 			goto out;
1364 		}
1365 
1366 		/* Append it to the buffer. */
1367 		if ((r = ssh_packet_process_incoming(ssh, buf, len)) != 0)
1368 			goto out;
1369 	}
1370  out:
1371 	free(setp);
1372 	return r;
1373 }
1374 
1375 int
1376 ssh_packet_read(struct ssh *ssh)
1377 {
1378 	u_char type;
1379 	int r;
1380 
1381 	if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0)
1382 		fatal("%s: %s", __func__, ssh_err(r));
1383 	return type;
1384 }
1385 
1386 /*
1387  * Waits until a packet has been received, verifies that its type matches
1388  * that given, and gives a fatal error and exits if there is a mismatch.
1389  */
1390 
1391 int
1392 ssh_packet_read_expect(struct ssh *ssh, u_int expected_type)
1393 {
1394 	int r;
1395 	u_char type;
1396 
1397 	if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0)
1398 		return r;
1399 	if (type != expected_type) {
1400 		if ((r = sshpkt_disconnect(ssh,
1401 		    "Protocol error: expected packet type %d, got %d",
1402 		    expected_type, type)) != 0)
1403 			return r;
1404 		return SSH_ERR_PROTOCOL_ERROR;
1405 	}
1406 	return 0;
1407 }
1408 
1409 static int
1410 ssh_packet_read_poll2_mux(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
1411 {
1412 	struct session_state *state = ssh->state;
1413 	const u_char *cp;
1414 	size_t need;
1415 	int r;
1416 
1417 	if (ssh->kex)
1418 		return SSH_ERR_INTERNAL_ERROR;
1419 	*typep = SSH_MSG_NONE;
1420 	cp = sshbuf_ptr(state->input);
1421 	if (state->packlen == 0) {
1422 		if (sshbuf_len(state->input) < 4 + 1)
1423 			return 0; /* packet is incomplete */
1424 		state->packlen = PEEK_U32(cp);
1425 		if (state->packlen < 4 + 1 ||
1426 		    state->packlen > PACKET_MAX_SIZE)
1427 			return SSH_ERR_MESSAGE_INCOMPLETE;
1428 	}
1429 	need = state->packlen + 4;
1430 	if (sshbuf_len(state->input) < need)
1431 		return 0; /* packet is incomplete */
1432 	sshbuf_reset(state->incoming_packet);
1433 	if ((r = sshbuf_put(state->incoming_packet, cp + 4,
1434 	    state->packlen)) != 0 ||
1435 	    (r = sshbuf_consume(state->input, need)) != 0 ||
1436 	    (r = sshbuf_get_u8(state->incoming_packet, NULL)) != 0 ||
1437 	    (r = sshbuf_get_u8(state->incoming_packet, typep)) != 0)
1438 		return r;
1439 	if (ssh_packet_log_type(*typep))
1440 		debug3("%s: type %u", __func__, *typep);
1441 	/* sshbuf_dump(state->incoming_packet, stderr); */
1442 	/* reset for next packet */
1443 	state->packlen = 0;
1444 	return r;
1445 }
1446 
1447 int
1448 ssh_packet_read_poll2(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
1449 {
1450 	struct session_state *state = ssh->state;
1451 	u_int padlen, need;
1452 	u_char *cp;
1453 	u_int maclen, aadlen = 0, authlen = 0, block_size;
1454 	struct sshenc *enc   = NULL;
1455 	struct sshmac *mac   = NULL;
1456 	struct sshcomp *comp = NULL;
1457 	int r;
1458 
1459 	if (state->mux)
1460 		return ssh_packet_read_poll2_mux(ssh, typep, seqnr_p);
1461 
1462 	*typep = SSH_MSG_NONE;
1463 
1464 	if (state->packet_discard)
1465 		return 0;
1466 
1467 	if (state->newkeys[MODE_IN] != NULL) {
1468 		enc  = &state->newkeys[MODE_IN]->enc;
1469 		mac  = &state->newkeys[MODE_IN]->mac;
1470 		comp = &state->newkeys[MODE_IN]->comp;
1471 		/* disable mac for authenticated encryption */
1472 		if ((authlen = cipher_authlen(enc->cipher)) != 0)
1473 			mac = NULL;
1474 	}
1475 	maclen = mac && mac->enabled ? mac->mac_len : 0;
1476 	block_size = enc ? enc->block_size : 8;
1477 	aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0;
1478 
1479 	if (aadlen && state->packlen == 0) {
1480 		if (cipher_get_length(state->receive_context,
1481 		    &state->packlen, state->p_read.seqnr,
1482 		    sshbuf_ptr(state->input), sshbuf_len(state->input)) != 0)
1483 			return 0;
1484 		if (state->packlen < 1 + 4 ||
1485 		    state->packlen > PACKET_MAX_SIZE) {
1486 #ifdef PACKET_DEBUG
1487 			sshbuf_dump(state->input, stderr);
1488 #endif
1489 			logit("Bad packet length %u.", state->packlen);
1490 			if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0)
1491 				return r;
1492 			return SSH_ERR_CONN_CORRUPT;
1493 		}
1494 		sshbuf_reset(state->incoming_packet);
1495 	} else if (state->packlen == 0) {
1496 		/*
1497 		 * check if input size is less than the cipher block size,
1498 		 * decrypt first block and extract length of incoming packet
1499 		 */
1500 		if (sshbuf_len(state->input) < block_size)
1501 			return 0;
1502 		sshbuf_reset(state->incoming_packet);
1503 		if ((r = sshbuf_reserve(state->incoming_packet, block_size,
1504 		    &cp)) != 0)
1505 			goto out;
1506 		if ((r = cipher_crypt(state->receive_context,
1507 		    state->p_send.seqnr, cp, sshbuf_ptr(state->input),
1508 		    block_size, 0, 0)) != 0)
1509 			goto out;
1510 		state->packlen = PEEK_U32(sshbuf_ptr(state->incoming_packet));
1511 		if (state->packlen < 1 + 4 ||
1512 		    state->packlen > PACKET_MAX_SIZE) {
1513 #ifdef PACKET_DEBUG
1514 			fprintf(stderr, "input: \n");
1515 			sshbuf_dump(state->input, stderr);
1516 			fprintf(stderr, "incoming_packet: \n");
1517 			sshbuf_dump(state->incoming_packet, stderr);
1518 #endif
1519 			logit("Bad packet length %u.", state->packlen);
1520 			return ssh_packet_start_discard(ssh, enc, mac, 0,
1521 			    PACKET_MAX_SIZE);
1522 		}
1523 		if ((r = sshbuf_consume(state->input, block_size)) != 0)
1524 			goto out;
1525 	}
1526 	DBG(debug("input: packet len %u", state->packlen+4));
1527 
1528 	if (aadlen) {
1529 		/* only the payload is encrypted */
1530 		need = state->packlen;
1531 	} else {
1532 		/*
1533 		 * the payload size and the payload are encrypted, but we
1534 		 * have a partial packet of block_size bytes
1535 		 */
1536 		need = 4 + state->packlen - block_size;
1537 	}
1538 	DBG(debug("partial packet: block %d, need %d, maclen %d, authlen %d,"
1539 	    " aadlen %d", block_size, need, maclen, authlen, aadlen));
1540 	if (need % block_size != 0) {
1541 		logit("padding error: need %d block %d mod %d",
1542 		    need, block_size, need % block_size);
1543 		return ssh_packet_start_discard(ssh, enc, mac, 0,
1544 		    PACKET_MAX_SIZE - block_size);
1545 	}
1546 	/*
1547 	 * check if the entire packet has been received and
1548 	 * decrypt into incoming_packet:
1549 	 * 'aadlen' bytes are unencrypted, but authenticated.
1550 	 * 'need' bytes are encrypted, followed by either
1551 	 * 'authlen' bytes of authentication tag or
1552 	 * 'maclen' bytes of message authentication code.
1553 	 */
1554 	if (sshbuf_len(state->input) < aadlen + need + authlen + maclen)
1555 		return 0; /* packet is incomplete */
1556 #ifdef PACKET_DEBUG
1557 	fprintf(stderr, "read_poll enc/full: ");
1558 	sshbuf_dump(state->input, stderr);
1559 #endif
1560 	/* EtM: check mac over encrypted input */
1561 	if (mac && mac->enabled && mac->etm) {
1562 		if ((r = mac_check(mac, state->p_read.seqnr,
1563 		    sshbuf_ptr(state->input), aadlen + need,
1564 		    sshbuf_ptr(state->input) + aadlen + need + authlen,
1565 		    maclen)) != 0) {
1566 			if (r == SSH_ERR_MAC_INVALID)
1567 				logit("Corrupted MAC on input.");
1568 			goto out;
1569 		}
1570 	}
1571 	if ((r = sshbuf_reserve(state->incoming_packet, aadlen + need,
1572 	    &cp)) != 0)
1573 		goto out;
1574 	if ((r = cipher_crypt(state->receive_context, state->p_read.seqnr, cp,
1575 	    sshbuf_ptr(state->input), need, aadlen, authlen)) != 0)
1576 		goto out;
1577 	if ((r = sshbuf_consume(state->input, aadlen + need + authlen)) != 0)
1578 		goto out;
1579 	if (mac && mac->enabled) {
1580 		/* Not EtM: check MAC over cleartext */
1581 		if (!mac->etm && (r = mac_check(mac, state->p_read.seqnr,
1582 		    sshbuf_ptr(state->incoming_packet),
1583 		    sshbuf_len(state->incoming_packet),
1584 		    sshbuf_ptr(state->input), maclen)) != 0) {
1585 			if (r != SSH_ERR_MAC_INVALID)
1586 				goto out;
1587 			logit("Corrupted MAC on input.");
1588 			if (need + block_size > PACKET_MAX_SIZE)
1589 				return SSH_ERR_INTERNAL_ERROR;
1590 			return ssh_packet_start_discard(ssh, enc, mac,
1591 			    sshbuf_len(state->incoming_packet),
1592 			    PACKET_MAX_SIZE - need - block_size);
1593 		}
1594 		/* Remove MAC from input buffer */
1595 		DBG(debug("MAC #%d ok", state->p_read.seqnr));
1596 		if ((r = sshbuf_consume(state->input, mac->mac_len)) != 0)
1597 			goto out;
1598 	}
1599 	if (seqnr_p != NULL)
1600 		*seqnr_p = state->p_read.seqnr;
1601 	if (++state->p_read.seqnr == 0)
1602 		logit("incoming seqnr wraps around");
1603 	if (++state->p_read.packets == 0)
1604 		if (!(ssh->compat & SSH_BUG_NOREKEY))
1605 			return SSH_ERR_NEED_REKEY;
1606 	state->p_read.blocks += (state->packlen + 4) / block_size;
1607 	state->p_read.bytes += state->packlen + 4;
1608 
1609 	/* get padlen */
1610 	padlen = sshbuf_ptr(state->incoming_packet)[4];
1611 	DBG(debug("input: padlen %d", padlen));
1612 	if (padlen < 4)	{
1613 		if ((r = sshpkt_disconnect(ssh,
1614 		    "Corrupted padlen %d on input.", padlen)) != 0 ||
1615 		    (r = ssh_packet_write_wait(ssh)) != 0)
1616 			return r;
1617 		return SSH_ERR_CONN_CORRUPT;
1618 	}
1619 
1620 	/* skip packet size + padlen, discard padding */
1621 	if ((r = sshbuf_consume(state->incoming_packet, 4 + 1)) != 0 ||
1622 	    ((r = sshbuf_consume_end(state->incoming_packet, padlen)) != 0))
1623 		goto out;
1624 
1625 	DBG(debug("input: len before de-compress %zd",
1626 	    sshbuf_len(state->incoming_packet)));
1627 	if (comp && comp->enabled) {
1628 		sshbuf_reset(state->compression_buffer);
1629 		if ((r = uncompress_buffer(ssh, state->incoming_packet,
1630 		    state->compression_buffer)) != 0)
1631 			goto out;
1632 		sshbuf_reset(state->incoming_packet);
1633 		if ((r = sshbuf_putb(state->incoming_packet,
1634 		    state->compression_buffer)) != 0)
1635 			goto out;
1636 		DBG(debug("input: len after de-compress %zd",
1637 		    sshbuf_len(state->incoming_packet)));
1638 	}
1639 	/*
1640 	 * get packet type, implies consume.
1641 	 * return length of payload (without type field)
1642 	 */
1643 	if ((r = sshbuf_get_u8(state->incoming_packet, typep)) != 0)
1644 		goto out;
1645 	if (ssh_packet_log_type(*typep))
1646 		debug3("receive packet: type %u", *typep);
1647 	if (*typep < SSH2_MSG_MIN || *typep >= SSH2_MSG_LOCAL_MIN) {
1648 		if ((r = sshpkt_disconnect(ssh,
1649 		    "Invalid ssh2 packet type: %d", *typep)) != 0 ||
1650 		    (r = ssh_packet_write_wait(ssh)) != 0)
1651 			return r;
1652 		return SSH_ERR_PROTOCOL_ERROR;
1653 	}
1654 	if (state->hook_in != NULL &&
1655 	    (r = state->hook_in(ssh, state->incoming_packet, typep,
1656 	    state->hook_in_ctx)) != 0)
1657 		return r;
1658 	if (*typep == SSH2_MSG_USERAUTH_SUCCESS && !state->server_side)
1659 		r = ssh_packet_enable_delayed_compress(ssh);
1660 	else
1661 		r = 0;
1662 #ifdef PACKET_DEBUG
1663 	fprintf(stderr, "read/plain[%d]:\r\n", *typep);
1664 	sshbuf_dump(state->incoming_packet, stderr);
1665 #endif
1666 	/* reset for next packet */
1667 	state->packlen = 0;
1668 
1669 	/* do we need to rekey? */
1670 	if (ssh_packet_need_rekeying(ssh, 0)) {
1671 		debug3("%s: rekex triggered", __func__);
1672 		if ((r = kex_start_rekex(ssh)) != 0)
1673 			return r;
1674 	}
1675  out:
1676 	return r;
1677 }
1678 
1679 int
1680 ssh_packet_read_poll_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
1681 {
1682 	struct session_state *state = ssh->state;
1683 	u_int reason, seqnr;
1684 	int r;
1685 	u_char *msg;
1686 
1687 	for (;;) {
1688 		msg = NULL;
1689 		r = ssh_packet_read_poll2(ssh, typep, seqnr_p);
1690 		if (r != 0)
1691 			return r;
1692 		if (*typep) {
1693 			state->keep_alive_timeouts = 0;
1694 			DBG(debug("received packet type %d", *typep));
1695 		}
1696 		switch (*typep) {
1697 		case SSH2_MSG_IGNORE:
1698 			debug3("Received SSH2_MSG_IGNORE");
1699 			break;
1700 		case SSH2_MSG_DEBUG:
1701 			if ((r = sshpkt_get_u8(ssh, NULL)) != 0 ||
1702 			    (r = sshpkt_get_string(ssh, &msg, NULL)) != 0 ||
1703 			    (r = sshpkt_get_string(ssh, NULL, NULL)) != 0) {
1704 				free(msg);
1705 				return r;
1706 			}
1707 			debug("Remote: %.900s", msg);
1708 			free(msg);
1709 			break;
1710 		case SSH2_MSG_DISCONNECT:
1711 			if ((r = sshpkt_get_u32(ssh, &reason)) != 0 ||
1712 			    (r = sshpkt_get_string(ssh, &msg, NULL)) != 0)
1713 				return r;
1714 			/* Ignore normal client exit notifications */
1715 			do_log2(ssh->state->server_side &&
1716 			    reason == SSH2_DISCONNECT_BY_APPLICATION ?
1717 			    SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_ERROR,
1718 			    "Received disconnect from %s port %d:"
1719 			    "%u: %.400s", ssh_remote_ipaddr(ssh),
1720 			    ssh_remote_port(ssh), reason, msg);
1721 			free(msg);
1722 			return SSH_ERR_DISCONNECTED;
1723 		case SSH2_MSG_UNIMPLEMENTED:
1724 			if ((r = sshpkt_get_u32(ssh, &seqnr)) != 0)
1725 				return r;
1726 			debug("Received SSH2_MSG_UNIMPLEMENTED for %u",
1727 			    seqnr);
1728 			break;
1729 		default:
1730 			return 0;
1731 		}
1732 	}
1733 }
1734 
1735 /*
1736  * Buffers the given amount of input characters.  This is intended to be used
1737  * together with packet_read_poll.
1738  */
1739 
1740 int
1741 ssh_packet_process_incoming(struct ssh *ssh, const char *buf, u_int len)
1742 {
1743 	struct session_state *state = ssh->state;
1744 	int r;
1745 
1746 	if (state->packet_discard) {
1747 		state->keep_alive_timeouts = 0; /* ?? */
1748 		if (len >= state->packet_discard) {
1749 			if ((r = ssh_packet_stop_discard(ssh)) != 0)
1750 				return r;
1751 		}
1752 		state->packet_discard -= len;
1753 		return 0;
1754 	}
1755 	if ((r = sshbuf_put(ssh->state->input, buf, len)) != 0)
1756 		return r;
1757 
1758 	return 0;
1759 }
1760 
1761 int
1762 ssh_packet_remaining(struct ssh *ssh)
1763 {
1764 	return sshbuf_len(ssh->state->incoming_packet);
1765 }
1766 
1767 /*
1768  * Sends a diagnostic message from the server to the client.  This message
1769  * can be sent at any time (but not while constructing another message). The
1770  * message is printed immediately, but only if the client is being executed
1771  * in verbose mode.  These messages are primarily intended to ease debugging
1772  * authentication problems.   The length of the formatted message must not
1773  * exceed 1024 bytes.  This will automatically call ssh_packet_write_wait.
1774  */
1775 void
1776 ssh_packet_send_debug(struct ssh *ssh, const char *fmt,...)
1777 {
1778 	char buf[1024];
1779 	va_list args;
1780 	int r;
1781 
1782 	if ((ssh->compat & SSH_BUG_DEBUG))
1783 		return;
1784 
1785 	va_start(args, fmt);
1786 	vsnprintf(buf, sizeof(buf), fmt, args);
1787 	va_end(args);
1788 
1789 	debug3("sending debug message: %s", buf);
1790 
1791 	if ((r = sshpkt_start(ssh, SSH2_MSG_DEBUG)) != 0 ||
1792 	    (r = sshpkt_put_u8(ssh, 0)) != 0 || /* always display */
1793 	    (r = sshpkt_put_cstring(ssh, buf)) != 0 ||
1794 	    (r = sshpkt_put_cstring(ssh, "")) != 0 ||
1795 	    (r = sshpkt_send(ssh)) != 0 ||
1796 	    (r = ssh_packet_write_wait(ssh)) != 0)
1797 		fatal("%s: %s", __func__, ssh_err(r));
1798 }
1799 
1800 void
1801 sshpkt_fmt_connection_id(struct ssh *ssh, char *s, size_t l)
1802 {
1803 	snprintf(s, l, "%.200s%s%s port %d",
1804 	    ssh->log_preamble ? ssh->log_preamble : "",
1805 	    ssh->log_preamble ? " " : "",
1806 	    ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
1807 }
1808 
1809 /*
1810  * Pretty-print connection-terminating errors and exit.
1811  */
1812 static void
1813 sshpkt_vfatal(struct ssh *ssh, int r, const char *fmt, va_list ap)
1814 {
1815 	char *tag = NULL, remote_id[512];
1816 
1817 	sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id));
1818 
1819 	switch (r) {
1820 	case SSH_ERR_CONN_CLOSED:
1821 		ssh_packet_clear_keys(ssh);
1822 		logdie("Connection closed by %s", remote_id);
1823 	case SSH_ERR_CONN_TIMEOUT:
1824 		ssh_packet_clear_keys(ssh);
1825 		logdie("Connection %s %s timed out",
1826 		    ssh->state->server_side ? "from" : "to", remote_id);
1827 	case SSH_ERR_DISCONNECTED:
1828 		ssh_packet_clear_keys(ssh);
1829 		logdie("Disconnected from %s", remote_id);
1830 	case SSH_ERR_SYSTEM_ERROR:
1831 		if (errno == ECONNRESET) {
1832 			ssh_packet_clear_keys(ssh);
1833 			logdie("Connection reset by %s", remote_id);
1834 		}
1835 		/* FALLTHROUGH */
1836 	case SSH_ERR_NO_CIPHER_ALG_MATCH:
1837 	case SSH_ERR_NO_MAC_ALG_MATCH:
1838 	case SSH_ERR_NO_COMPRESS_ALG_MATCH:
1839 	case SSH_ERR_NO_KEX_ALG_MATCH:
1840 	case SSH_ERR_NO_HOSTKEY_ALG_MATCH:
1841 		if (ssh && ssh->kex && ssh->kex->failed_choice) {
1842 			ssh_packet_clear_keys(ssh);
1843 			logdie("Unable to negotiate with %s: %s. "
1844 			    "Their offer: %s", remote_id, ssh_err(r),
1845 			    ssh->kex->failed_choice);
1846 		}
1847 		/* FALLTHROUGH */
1848 	default:
1849 		if (vasprintf(&tag, fmt, ap) == -1) {
1850 			ssh_packet_clear_keys(ssh);
1851 			logdie("%s: could not allocate failure message",
1852 			    __func__);
1853 		}
1854 		ssh_packet_clear_keys(ssh);
1855 		logdie("%s%sConnection %s %s: %s",
1856 		    tag != NULL ? tag : "", tag != NULL ? ": " : "",
1857 		    ssh->state->server_side ? "from" : "to",
1858 		    remote_id, ssh_err(r));
1859 	}
1860 }
1861 
1862 void
1863 sshpkt_fatal(struct ssh *ssh, int r, const char *fmt, ...)
1864 {
1865 	va_list ap;
1866 
1867 	va_start(ap, fmt);
1868 	sshpkt_vfatal(ssh, r, fmt, ap);
1869 	/* NOTREACHED */
1870 	va_end(ap);
1871 	logdie("%s: should have exited", __func__);
1872 }
1873 
1874 /*
1875  * Logs the error plus constructs and sends a disconnect packet, closes the
1876  * connection, and exits.  This function never returns. The error message
1877  * should not contain a newline.  The length of the formatted message must
1878  * not exceed 1024 bytes.
1879  */
1880 void
1881 ssh_packet_disconnect(struct ssh *ssh, const char *fmt,...)
1882 {
1883 	char buf[1024], remote_id[512];
1884 	va_list args;
1885 	static int disconnecting = 0;
1886 	int r;
1887 
1888 	if (disconnecting)	/* Guard against recursive invocations. */
1889 		fatal("packet_disconnect called recursively.");
1890 	disconnecting = 1;
1891 
1892 	/*
1893 	 * Format the message.  Note that the caller must make sure the
1894 	 * message is of limited size.
1895 	 */
1896 	sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id));
1897 	va_start(args, fmt);
1898 	vsnprintf(buf, sizeof(buf), fmt, args);
1899 	va_end(args);
1900 
1901 	/* Display the error locally */
1902 	logit("Disconnecting %s: %.100s", remote_id, buf);
1903 
1904 	/*
1905 	 * Send the disconnect message to the other side, and wait
1906 	 * for it to get sent.
1907 	 */
1908 	if ((r = sshpkt_disconnect(ssh, "%s", buf)) != 0)
1909 		sshpkt_fatal(ssh, r, "%s", __func__);
1910 
1911 	if ((r = ssh_packet_write_wait(ssh)) != 0)
1912 		sshpkt_fatal(ssh, r, "%s", __func__);
1913 
1914 	/* Close the connection. */
1915 	ssh_packet_close(ssh);
1916 	cleanup_exit(255);
1917 }
1918 
1919 /*
1920  * Checks if there is any buffered output, and tries to write some of
1921  * the output.
1922  */
1923 int
1924 ssh_packet_write_poll(struct ssh *ssh)
1925 {
1926 	struct session_state *state = ssh->state;
1927 	int len = sshbuf_len(state->output);
1928 	int r;
1929 
1930 	if (len > 0) {
1931 		len = write(state->connection_out,
1932 		    sshbuf_ptr(state->output), len);
1933 		if (len == -1) {
1934 			if (errno == EINTR || errno == EAGAIN ||
1935 			    errno == EWOULDBLOCK)
1936 				return 0;
1937 			return SSH_ERR_SYSTEM_ERROR;
1938 		}
1939 		if (len == 0)
1940 			return SSH_ERR_CONN_CLOSED;
1941 		if ((r = sshbuf_consume(state->output, len)) != 0)
1942 			return r;
1943 	}
1944 	return 0;
1945 }
1946 
1947 /*
1948  * Calls packet_write_poll repeatedly until all pending output data has been
1949  * written.
1950  */
1951 int
1952 ssh_packet_write_wait(struct ssh *ssh)
1953 {
1954 	fd_set *setp;
1955 	int ret, r, ms_remain = 0;
1956 	struct timeval start, timeout, *timeoutp = NULL;
1957 	struct session_state *state = ssh->state;
1958 
1959 	setp = calloc(howmany(state->connection_out + 1,
1960 	    NFDBITS), sizeof(fd_mask));
1961 	if (setp == NULL)
1962 		return SSH_ERR_ALLOC_FAIL;
1963 	if ((r = ssh_packet_write_poll(ssh)) != 0) {
1964 		free(setp);
1965 		return r;
1966 	}
1967 	while (ssh_packet_have_data_to_write(ssh)) {
1968 		memset(setp, 0, howmany(state->connection_out + 1,
1969 		    NFDBITS) * sizeof(fd_mask));
1970 		FD_SET(state->connection_out, setp);
1971 
1972 		if (state->packet_timeout_ms > 0) {
1973 			ms_remain = state->packet_timeout_ms;
1974 			timeoutp = &timeout;
1975 		}
1976 		for (;;) {
1977 			if (state->packet_timeout_ms != -1) {
1978 				ms_to_timeval(&timeout, ms_remain);
1979 				monotime_tv(&start);
1980 			}
1981 			if ((ret = select(state->connection_out + 1,
1982 			    NULL, setp, NULL, timeoutp)) >= 0)
1983 				break;
1984 			if (errno != EAGAIN && errno != EINTR &&
1985 			    errno != EWOULDBLOCK)
1986 				break;
1987 			if (state->packet_timeout_ms == -1)
1988 				continue;
1989 			ms_subtract_diff(&start, &ms_remain);
1990 			if (ms_remain <= 0) {
1991 				ret = 0;
1992 				break;
1993 			}
1994 		}
1995 		if (ret == 0) {
1996 			free(setp);
1997 			return SSH_ERR_CONN_TIMEOUT;
1998 		}
1999 		if ((r = ssh_packet_write_poll(ssh)) != 0) {
2000 			free(setp);
2001 			return r;
2002 		}
2003 	}
2004 	free(setp);
2005 	return 0;
2006 }
2007 
2008 /* Returns true if there is buffered data to write to the connection. */
2009 
2010 int
2011 ssh_packet_have_data_to_write(struct ssh *ssh)
2012 {
2013 	return sshbuf_len(ssh->state->output) != 0;
2014 }
2015 
2016 /* Returns true if there is not too much data to write to the connection. */
2017 
2018 int
2019 ssh_packet_not_very_much_data_to_write(struct ssh *ssh)
2020 {
2021 	if (ssh->state->interactive_mode)
2022 		return sshbuf_len(ssh->state->output) < 16384;
2023 	else
2024 		return sshbuf_len(ssh->state->output) < 128 * 1024;
2025 }
2026 
2027 void
2028 ssh_packet_set_tos(struct ssh *ssh, int tos)
2029 {
2030 #ifndef IP_TOS_IS_BROKEN
2031 	if (!ssh_packet_connection_is_on_socket(ssh) || tos == INT_MAX)
2032 		return;
2033 	switch (ssh_packet_connection_af(ssh)) {
2034 # ifdef IP_TOS
2035 	case AF_INET:
2036 		debug3("%s: set IP_TOS 0x%02x", __func__, tos);
2037 		if (setsockopt(ssh->state->connection_in,
2038 		    IPPROTO_IP, IP_TOS, &tos, sizeof(tos)) < 0)
2039 			error("setsockopt IP_TOS %d: %.100s:",
2040 			    tos, strerror(errno));
2041 		break;
2042 # endif /* IP_TOS */
2043 # ifdef IPV6_TCLASS
2044 	case AF_INET6:
2045 		debug3("%s: set IPV6_TCLASS 0x%02x", __func__, tos);
2046 		if (setsockopt(ssh->state->connection_in,
2047 		    IPPROTO_IPV6, IPV6_TCLASS, &tos, sizeof(tos)) < 0)
2048 			error("setsockopt IPV6_TCLASS %d: %.100s:",
2049 			    tos, strerror(errno));
2050 		break;
2051 # endif /* IPV6_TCLASS */
2052 	}
2053 #endif /* IP_TOS_IS_BROKEN */
2054 }
2055 
2056 /* Informs that the current session is interactive.  Sets IP flags for that. */
2057 
2058 void
2059 ssh_packet_set_interactive(struct ssh *ssh, int interactive, int qos_interactive, int qos_bulk)
2060 {
2061 	struct session_state *state = ssh->state;
2062 
2063 	if (state->set_interactive_called)
2064 		return;
2065 	state->set_interactive_called = 1;
2066 
2067 	/* Record that we are in interactive mode. */
2068 	state->interactive_mode = interactive;
2069 
2070 	/* Only set socket options if using a socket.  */
2071 	if (!ssh_packet_connection_is_on_socket(ssh))
2072 		return;
2073 	set_nodelay(state->connection_in);
2074 	ssh_packet_set_tos(ssh, interactive ? qos_interactive :
2075 	    qos_bulk);
2076 }
2077 
2078 /* Returns true if the current connection is interactive. */
2079 
2080 int
2081 ssh_packet_is_interactive(struct ssh *ssh)
2082 {
2083 	return ssh->state->interactive_mode;
2084 }
2085 
2086 int
2087 ssh_packet_set_maxsize(struct ssh *ssh, u_int s)
2088 {
2089 	struct session_state *state = ssh->state;
2090 
2091 	if (state->set_maxsize_called) {
2092 		logit("packet_set_maxsize: called twice: old %d new %d",
2093 		    state->max_packet_size, s);
2094 		return -1;
2095 	}
2096 	if (s < 4 * 1024 || s > 1024 * 1024) {
2097 		logit("packet_set_maxsize: bad size %d", s);
2098 		return -1;
2099 	}
2100 	state->set_maxsize_called = 1;
2101 	debug("packet_set_maxsize: setting to %d", s);
2102 	state->max_packet_size = s;
2103 	return s;
2104 }
2105 
2106 int
2107 ssh_packet_inc_alive_timeouts(struct ssh *ssh)
2108 {
2109 	return ++ssh->state->keep_alive_timeouts;
2110 }
2111 
2112 void
2113 ssh_packet_set_alive_timeouts(struct ssh *ssh, int ka)
2114 {
2115 	ssh->state->keep_alive_timeouts = ka;
2116 }
2117 
2118 u_int
2119 ssh_packet_get_maxsize(struct ssh *ssh)
2120 {
2121 	return ssh->state->max_packet_size;
2122 }
2123 
2124 void
2125 ssh_packet_set_rekey_limits(struct ssh *ssh, u_int64_t bytes, u_int32_t seconds)
2126 {
2127 	debug3("rekey after %llu bytes, %u seconds", (unsigned long long)bytes,
2128 	    (unsigned int)seconds);
2129 	ssh->state->rekey_limit = bytes;
2130 	ssh->state->rekey_interval = seconds;
2131 }
2132 
2133 time_t
2134 ssh_packet_get_rekey_timeout(struct ssh *ssh)
2135 {
2136 	time_t seconds;
2137 
2138 	seconds = ssh->state->rekey_time + ssh->state->rekey_interval -
2139 	    monotime();
2140 	return (seconds <= 0 ? 1 : seconds);
2141 }
2142 
2143 void
2144 ssh_packet_set_server(struct ssh *ssh)
2145 {
2146 	ssh->state->server_side = 1;
2147 	ssh->kex->server = 1; /* XXX unify? */
2148 }
2149 
2150 void
2151 ssh_packet_set_authenticated(struct ssh *ssh)
2152 {
2153 	ssh->state->after_authentication = 1;
2154 }
2155 
2156 void *
2157 ssh_packet_get_input(struct ssh *ssh)
2158 {
2159 	return (void *)ssh->state->input;
2160 }
2161 
2162 void *
2163 ssh_packet_get_output(struct ssh *ssh)
2164 {
2165 	return (void *)ssh->state->output;
2166 }
2167 
2168 /* Reset after_authentication and reset compression in post-auth privsep */
2169 static int
2170 ssh_packet_set_postauth(struct ssh *ssh)
2171 {
2172 	int r;
2173 
2174 	debug("%s: called", __func__);
2175 	/* This was set in net child, but is not visible in user child */
2176 	ssh->state->after_authentication = 1;
2177 	ssh->state->rekeying = 0;
2178 	if ((r = ssh_packet_enable_delayed_compress(ssh)) != 0)
2179 		return r;
2180 	return 0;
2181 }
2182 
2183 /* Packet state (de-)serialization for privsep */
2184 
2185 /* turn kex into a blob for packet state serialization */
2186 static int
2187 kex_to_blob(struct sshbuf *m, struct kex *kex)
2188 {
2189 	int r;
2190 
2191 	if ((r = sshbuf_put_string(m, kex->session_id,
2192 	    kex->session_id_len)) != 0 ||
2193 	    (r = sshbuf_put_u32(m, kex->we_need)) != 0 ||
2194 	    (r = sshbuf_put_cstring(m, kex->hostkey_alg)) != 0 ||
2195 	    (r = sshbuf_put_u32(m, kex->hostkey_type)) != 0 ||
2196 	    (r = sshbuf_put_u32(m, kex->hostkey_nid)) != 0 ||
2197 	    (r = sshbuf_put_u32(m, kex->kex_type)) != 0 ||
2198 	    (r = sshbuf_put_stringb(m, kex->my)) != 0 ||
2199 	    (r = sshbuf_put_stringb(m, kex->peer)) != 0 ||
2200 	    (r = sshbuf_put_stringb(m, kex->client_version)) != 0 ||
2201 	    (r = sshbuf_put_stringb(m, kex->server_version)) != 0 ||
2202 	    (r = sshbuf_put_u32(m, kex->flags)) != 0)
2203 		return r;
2204 	return 0;
2205 }
2206 
2207 /* turn key exchange results into a blob for packet state serialization */
2208 static int
2209 newkeys_to_blob(struct sshbuf *m, struct ssh *ssh, int mode)
2210 {
2211 	struct sshbuf *b;
2212 	struct sshcipher_ctx *cc;
2213 	struct sshcomp *comp;
2214 	struct sshenc *enc;
2215 	struct sshmac *mac;
2216 	struct newkeys *newkey;
2217 	int r;
2218 
2219 	if ((newkey = ssh->state->newkeys[mode]) == NULL)
2220 		return SSH_ERR_INTERNAL_ERROR;
2221 	enc = &newkey->enc;
2222 	mac = &newkey->mac;
2223 	comp = &newkey->comp;
2224 	cc = (mode == MODE_OUT) ? ssh->state->send_context :
2225 	    ssh->state->receive_context;
2226 	if ((r = cipher_get_keyiv(cc, enc->iv, enc->iv_len)) != 0)
2227 		return r;
2228 	if ((b = sshbuf_new()) == NULL)
2229 		return SSH_ERR_ALLOC_FAIL;
2230 	if ((r = sshbuf_put_cstring(b, enc->name)) != 0 ||
2231 	    (r = sshbuf_put_u32(b, enc->enabled)) != 0 ||
2232 	    (r = sshbuf_put_u32(b, enc->block_size)) != 0 ||
2233 	    (r = sshbuf_put_string(b, enc->key, enc->key_len)) != 0 ||
2234 	    (r = sshbuf_put_string(b, enc->iv, enc->iv_len)) != 0)
2235 		goto out;
2236 	if (cipher_authlen(enc->cipher) == 0) {
2237 		if ((r = sshbuf_put_cstring(b, mac->name)) != 0 ||
2238 		    (r = sshbuf_put_u32(b, mac->enabled)) != 0 ||
2239 		    (r = sshbuf_put_string(b, mac->key, mac->key_len)) != 0)
2240 			goto out;
2241 	}
2242 	if ((r = sshbuf_put_u32(b, comp->type)) != 0 ||
2243 	    (r = sshbuf_put_cstring(b, comp->name)) != 0)
2244 		goto out;
2245 	r = sshbuf_put_stringb(m, b);
2246  out:
2247 	sshbuf_free(b);
2248 	return r;
2249 }
2250 
2251 /* serialize packet state into a blob */
2252 int
2253 ssh_packet_get_state(struct ssh *ssh, struct sshbuf *m)
2254 {
2255 	struct session_state *state = ssh->state;
2256 	int r;
2257 
2258 	if ((r = kex_to_blob(m, ssh->kex)) != 0 ||
2259 	    (r = newkeys_to_blob(m, ssh, MODE_OUT)) != 0 ||
2260 	    (r = newkeys_to_blob(m, ssh, MODE_IN)) != 0 ||
2261 	    (r = sshbuf_put_u64(m, state->rekey_limit)) != 0 ||
2262 	    (r = sshbuf_put_u32(m, state->rekey_interval)) != 0 ||
2263 	    (r = sshbuf_put_u32(m, state->p_send.seqnr)) != 0 ||
2264 	    (r = sshbuf_put_u64(m, state->p_send.blocks)) != 0 ||
2265 	    (r = sshbuf_put_u32(m, state->p_send.packets)) != 0 ||
2266 	    (r = sshbuf_put_u64(m, state->p_send.bytes)) != 0 ||
2267 	    (r = sshbuf_put_u32(m, state->p_read.seqnr)) != 0 ||
2268 	    (r = sshbuf_put_u64(m, state->p_read.blocks)) != 0 ||
2269 	    (r = sshbuf_put_u32(m, state->p_read.packets)) != 0 ||
2270 	    (r = sshbuf_put_u64(m, state->p_read.bytes)) != 0 ||
2271 	    (r = sshbuf_put_stringb(m, state->input)) != 0 ||
2272 	    (r = sshbuf_put_stringb(m, state->output)) != 0)
2273 		return r;
2274 
2275 	return 0;
2276 }
2277 
2278 /* restore key exchange results from blob for packet state de-serialization */
2279 static int
2280 newkeys_from_blob(struct sshbuf *m, struct ssh *ssh, int mode)
2281 {
2282 	struct sshbuf *b = NULL;
2283 	struct sshcomp *comp;
2284 	struct sshenc *enc;
2285 	struct sshmac *mac;
2286 	struct newkeys *newkey = NULL;
2287 	size_t keylen, ivlen, maclen;
2288 	int r;
2289 
2290 	if ((newkey = calloc(1, sizeof(*newkey))) == NULL) {
2291 		r = SSH_ERR_ALLOC_FAIL;
2292 		goto out;
2293 	}
2294 	if ((r = sshbuf_froms(m, &b)) != 0)
2295 		goto out;
2296 #ifdef DEBUG_PK
2297 	sshbuf_dump(b, stderr);
2298 #endif
2299 	enc = &newkey->enc;
2300 	mac = &newkey->mac;
2301 	comp = &newkey->comp;
2302 
2303 	if ((r = sshbuf_get_cstring(b, &enc->name, NULL)) != 0 ||
2304 	    (r = sshbuf_get_u32(b, (u_int *)&enc->enabled)) != 0 ||
2305 	    (r = sshbuf_get_u32(b, &enc->block_size)) != 0 ||
2306 	    (r = sshbuf_get_string(b, &enc->key, &keylen)) != 0 ||
2307 	    (r = sshbuf_get_string(b, &enc->iv, &ivlen)) != 0)
2308 		goto out;
2309 	if ((enc->cipher = cipher_by_name(enc->name)) == NULL) {
2310 		r = SSH_ERR_INVALID_FORMAT;
2311 		goto out;
2312 	}
2313 	if (cipher_authlen(enc->cipher) == 0) {
2314 		if ((r = sshbuf_get_cstring(b, &mac->name, NULL)) != 0)
2315 			goto out;
2316 		if ((r = mac_setup(mac, mac->name)) != 0)
2317 			goto out;
2318 		if ((r = sshbuf_get_u32(b, (u_int *)&mac->enabled)) != 0 ||
2319 		    (r = sshbuf_get_string(b, &mac->key, &maclen)) != 0)
2320 			goto out;
2321 		if (maclen > mac->key_len) {
2322 			r = SSH_ERR_INVALID_FORMAT;
2323 			goto out;
2324 		}
2325 		mac->key_len = maclen;
2326 	}
2327 	if ((r = sshbuf_get_u32(b, &comp->type)) != 0 ||
2328 	    (r = sshbuf_get_cstring(b, &comp->name, NULL)) != 0)
2329 		goto out;
2330 	if (sshbuf_len(b) != 0) {
2331 		r = SSH_ERR_INVALID_FORMAT;
2332 		goto out;
2333 	}
2334 	enc->key_len = keylen;
2335 	enc->iv_len = ivlen;
2336 	ssh->kex->newkeys[mode] = newkey;
2337 	newkey = NULL;
2338 	r = 0;
2339  out:
2340 	free(newkey);
2341 	sshbuf_free(b);
2342 	return r;
2343 }
2344 
2345 /* restore kex from blob for packet state de-serialization */
2346 static int
2347 kex_from_blob(struct sshbuf *m, struct kex **kexp)
2348 {
2349 	struct kex *kex;
2350 	int r;
2351 
2352 	if ((kex = kex_new()) == NULL)
2353 		return SSH_ERR_ALLOC_FAIL;
2354 	if ((r = sshbuf_get_string(m, &kex->session_id, &kex->session_id_len)) != 0 ||
2355 	    (r = sshbuf_get_u32(m, &kex->we_need)) != 0 ||
2356 	    (r = sshbuf_get_cstring(m, &kex->hostkey_alg, NULL)) != 0 ||
2357 	    (r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_type)) != 0 ||
2358 	    (r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_nid)) != 0 ||
2359 	    (r = sshbuf_get_u32(m, &kex->kex_type)) != 0 ||
2360 	    (r = sshbuf_get_stringb(m, kex->my)) != 0 ||
2361 	    (r = sshbuf_get_stringb(m, kex->peer)) != 0 ||
2362 	    (r = sshbuf_get_stringb(m, kex->client_version)) != 0 ||
2363 	    (r = sshbuf_get_stringb(m, kex->server_version)) != 0 ||
2364 	    (r = sshbuf_get_u32(m, &kex->flags)) != 0)
2365 		goto out;
2366 	kex->server = 1;
2367 	kex->done = 1;
2368 	r = 0;
2369  out:
2370 	if (r != 0 || kexp == NULL) {
2371 		kex_free(kex);
2372 		if (kexp != NULL)
2373 			*kexp = NULL;
2374 	} else {
2375 		kex_free(*kexp);
2376 		*kexp = kex;
2377 	}
2378 	return r;
2379 }
2380 
2381 /*
2382  * Restore packet state from content of blob 'm' (de-serialization).
2383  * Note that 'm' will be partially consumed on parsing or any other errors.
2384  */
2385 int
2386 ssh_packet_set_state(struct ssh *ssh, struct sshbuf *m)
2387 {
2388 	struct session_state *state = ssh->state;
2389 	const u_char *input, *output;
2390 	size_t ilen, olen;
2391 	int r;
2392 
2393 	if ((r = kex_from_blob(m, &ssh->kex)) != 0 ||
2394 	    (r = newkeys_from_blob(m, ssh, MODE_OUT)) != 0 ||
2395 	    (r = newkeys_from_blob(m, ssh, MODE_IN)) != 0 ||
2396 	    (r = sshbuf_get_u64(m, &state->rekey_limit)) != 0 ||
2397 	    (r = sshbuf_get_u32(m, &state->rekey_interval)) != 0 ||
2398 	    (r = sshbuf_get_u32(m, &state->p_send.seqnr)) != 0 ||
2399 	    (r = sshbuf_get_u64(m, &state->p_send.blocks)) != 0 ||
2400 	    (r = sshbuf_get_u32(m, &state->p_send.packets)) != 0 ||
2401 	    (r = sshbuf_get_u64(m, &state->p_send.bytes)) != 0 ||
2402 	    (r = sshbuf_get_u32(m, &state->p_read.seqnr)) != 0 ||
2403 	    (r = sshbuf_get_u64(m, &state->p_read.blocks)) != 0 ||
2404 	    (r = sshbuf_get_u32(m, &state->p_read.packets)) != 0 ||
2405 	    (r = sshbuf_get_u64(m, &state->p_read.bytes)) != 0)
2406 		return r;
2407 	/*
2408 	 * We set the time here so that in post-auth privsep slave we
2409 	 * count from the completion of the authentication.
2410 	 */
2411 	state->rekey_time = monotime();
2412 	/* XXX ssh_set_newkeys overrides p_read.packets? XXX */
2413 	if ((r = ssh_set_newkeys(ssh, MODE_IN)) != 0 ||
2414 	    (r = ssh_set_newkeys(ssh, MODE_OUT)) != 0)
2415 		return r;
2416 
2417 	if ((r = ssh_packet_set_postauth(ssh)) != 0)
2418 		return r;
2419 
2420 	sshbuf_reset(state->input);
2421 	sshbuf_reset(state->output);
2422 	if ((r = sshbuf_get_string_direct(m, &input, &ilen)) != 0 ||
2423 	    (r = sshbuf_get_string_direct(m, &output, &olen)) != 0 ||
2424 	    (r = sshbuf_put(state->input, input, ilen)) != 0 ||
2425 	    (r = sshbuf_put(state->output, output, olen)) != 0)
2426 		return r;
2427 
2428 	if (sshbuf_len(m))
2429 		return SSH_ERR_INVALID_FORMAT;
2430 	debug3("%s: done", __func__);
2431 	return 0;
2432 }
2433 
2434 /* NEW API */
2435 
2436 /* put data to the outgoing packet */
2437 
2438 int
2439 sshpkt_put(struct ssh *ssh, const void *v, size_t len)
2440 {
2441 	return sshbuf_put(ssh->state->outgoing_packet, v, len);
2442 }
2443 
2444 int
2445 sshpkt_putb(struct ssh *ssh, const struct sshbuf *b)
2446 {
2447 	return sshbuf_putb(ssh->state->outgoing_packet, b);
2448 }
2449 
2450 int
2451 sshpkt_put_u8(struct ssh *ssh, u_char val)
2452 {
2453 	return sshbuf_put_u8(ssh->state->outgoing_packet, val);
2454 }
2455 
2456 int
2457 sshpkt_put_u32(struct ssh *ssh, u_int32_t val)
2458 {
2459 	return sshbuf_put_u32(ssh->state->outgoing_packet, val);
2460 }
2461 
2462 int
2463 sshpkt_put_u64(struct ssh *ssh, u_int64_t val)
2464 {
2465 	return sshbuf_put_u64(ssh->state->outgoing_packet, val);
2466 }
2467 
2468 int
2469 sshpkt_put_string(struct ssh *ssh, const void *v, size_t len)
2470 {
2471 	return sshbuf_put_string(ssh->state->outgoing_packet, v, len);
2472 }
2473 
2474 int
2475 sshpkt_put_cstring(struct ssh *ssh, const void *v)
2476 {
2477 	return sshbuf_put_cstring(ssh->state->outgoing_packet, v);
2478 }
2479 
2480 int
2481 sshpkt_put_stringb(struct ssh *ssh, const struct sshbuf *v)
2482 {
2483 	return sshbuf_put_stringb(ssh->state->outgoing_packet, v);
2484 }
2485 
2486 #ifdef WITH_OPENSSL
2487 #ifdef OPENSSL_HAS_ECC
2488 int
2489 sshpkt_put_ec(struct ssh *ssh, const EC_POINT *v, const EC_GROUP *g)
2490 {
2491 	return sshbuf_put_ec(ssh->state->outgoing_packet, v, g);
2492 }
2493 #endif /* OPENSSL_HAS_ECC */
2494 
2495 
2496 int
2497 sshpkt_put_bignum2(struct ssh *ssh, const BIGNUM *v)
2498 {
2499 	return sshbuf_put_bignum2(ssh->state->outgoing_packet, v);
2500 }
2501 #endif /* WITH_OPENSSL */
2502 
2503 /* fetch data from the incoming packet */
2504 
2505 int
2506 sshpkt_get(struct ssh *ssh, void *valp, size_t len)
2507 {
2508 	return sshbuf_get(ssh->state->incoming_packet, valp, len);
2509 }
2510 
2511 int
2512 sshpkt_get_u8(struct ssh *ssh, u_char *valp)
2513 {
2514 	return sshbuf_get_u8(ssh->state->incoming_packet, valp);
2515 }
2516 
2517 int
2518 sshpkt_get_u32(struct ssh *ssh, u_int32_t *valp)
2519 {
2520 	return sshbuf_get_u32(ssh->state->incoming_packet, valp);
2521 }
2522 
2523 int
2524 sshpkt_get_u64(struct ssh *ssh, u_int64_t *valp)
2525 {
2526 	return sshbuf_get_u64(ssh->state->incoming_packet, valp);
2527 }
2528 
2529 int
2530 sshpkt_get_string(struct ssh *ssh, u_char **valp, size_t *lenp)
2531 {
2532 	return sshbuf_get_string(ssh->state->incoming_packet, valp, lenp);
2533 }
2534 
2535 int
2536 sshpkt_get_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp)
2537 {
2538 	return sshbuf_get_string_direct(ssh->state->incoming_packet, valp, lenp);
2539 }
2540 
2541 int
2542 sshpkt_peek_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp)
2543 {
2544 	return sshbuf_peek_string_direct(ssh->state->incoming_packet, valp, lenp);
2545 }
2546 
2547 int
2548 sshpkt_get_cstring(struct ssh *ssh, char **valp, size_t *lenp)
2549 {
2550 	return sshbuf_get_cstring(ssh->state->incoming_packet, valp, lenp);
2551 }
2552 
2553 #ifdef WITH_OPENSSL
2554 #ifdef OPENSSL_HAS_ECC
2555 int
2556 sshpkt_get_ec(struct ssh *ssh, EC_POINT *v, const EC_GROUP *g)
2557 {
2558 	return sshbuf_get_ec(ssh->state->incoming_packet, v, g);
2559 }
2560 #endif /* OPENSSL_HAS_ECC */
2561 
2562 int
2563 sshpkt_get_bignum2(struct ssh *ssh, BIGNUM **valp)
2564 {
2565 	return sshbuf_get_bignum2(ssh->state->incoming_packet, valp);
2566 }
2567 #endif /* WITH_OPENSSL */
2568 
2569 int
2570 sshpkt_get_end(struct ssh *ssh)
2571 {
2572 	if (sshbuf_len(ssh->state->incoming_packet) > 0)
2573 		return SSH_ERR_UNEXPECTED_TRAILING_DATA;
2574 	return 0;
2575 }
2576 
2577 const u_char *
2578 sshpkt_ptr(struct ssh *ssh, size_t *lenp)
2579 {
2580 	if (lenp != NULL)
2581 		*lenp = sshbuf_len(ssh->state->incoming_packet);
2582 	return sshbuf_ptr(ssh->state->incoming_packet);
2583 }
2584 
2585 /* start a new packet */
2586 
2587 int
2588 sshpkt_start(struct ssh *ssh, u_char type)
2589 {
2590 	u_char buf[6]; /* u32 packet length, u8 pad len, u8 type */
2591 
2592 	DBG(debug("packet_start[%d]", type));
2593 	memset(buf, 0, sizeof(buf));
2594 	buf[sizeof(buf) - 1] = type;
2595 	sshbuf_reset(ssh->state->outgoing_packet);
2596 	return sshbuf_put(ssh->state->outgoing_packet, buf, sizeof(buf));
2597 }
2598 
2599 static int
2600 ssh_packet_send_mux(struct ssh *ssh)
2601 {
2602 	struct session_state *state = ssh->state;
2603 	u_char type, *cp;
2604 	size_t len;
2605 	int r;
2606 
2607 	if (ssh->kex)
2608 		return SSH_ERR_INTERNAL_ERROR;
2609 	len = sshbuf_len(state->outgoing_packet);
2610 	if (len < 6)
2611 		return SSH_ERR_INTERNAL_ERROR;
2612 	cp = sshbuf_mutable_ptr(state->outgoing_packet);
2613 	type = cp[5];
2614 	if (ssh_packet_log_type(type))
2615 		debug3("%s: type %u", __func__, type);
2616 	/* drop everything, but the connection protocol */
2617 	if (type >= SSH2_MSG_CONNECTION_MIN &&
2618 	    type <= SSH2_MSG_CONNECTION_MAX) {
2619 		POKE_U32(cp, len - 4);
2620 		if ((r = sshbuf_putb(state->output,
2621 		    state->outgoing_packet)) != 0)
2622 			return r;
2623 		/* sshbuf_dump(state->output, stderr); */
2624 	}
2625 	sshbuf_reset(state->outgoing_packet);
2626 	return 0;
2627 }
2628 
2629 /*
2630  * 9.2.  Ignored Data Message
2631  *
2632  *   byte      SSH_MSG_IGNORE
2633  *   string    data
2634  *
2635  * All implementations MUST understand (and ignore) this message at any
2636  * time (after receiving the protocol version). No implementation is
2637  * required to send them. This message can be used as an additional
2638  * protection measure against advanced traffic analysis techniques.
2639  */
2640 int
2641 sshpkt_msg_ignore(struct ssh *ssh, u_int nbytes)
2642 {
2643 	u_int32_t rnd = 0;
2644 	int r;
2645 	u_int i;
2646 
2647 	if ((r = sshpkt_start(ssh, SSH2_MSG_IGNORE)) != 0 ||
2648 	    (r = sshpkt_put_u32(ssh, nbytes)) != 0)
2649 		return r;
2650 	for (i = 0; i < nbytes; i++) {
2651 		if (i % 4 == 0)
2652 			rnd = arc4random();
2653 		if ((r = sshpkt_put_u8(ssh, (u_char)rnd & 0xff)) != 0)
2654 			return r;
2655 		rnd >>= 8;
2656 	}
2657 	return 0;
2658 }
2659 
2660 /* send it */
2661 
2662 int
2663 sshpkt_send(struct ssh *ssh)
2664 {
2665 	if (ssh->state && ssh->state->mux)
2666 		return ssh_packet_send_mux(ssh);
2667 	return ssh_packet_send2(ssh);
2668 }
2669 
2670 int
2671 sshpkt_disconnect(struct ssh *ssh, const char *fmt,...)
2672 {
2673 	char buf[1024];
2674 	va_list args;
2675 	int r;
2676 
2677 	va_start(args, fmt);
2678 	vsnprintf(buf, sizeof(buf), fmt, args);
2679 	va_end(args);
2680 
2681 	if ((r = sshpkt_start(ssh, SSH2_MSG_DISCONNECT)) != 0 ||
2682 	    (r = sshpkt_put_u32(ssh, SSH2_DISCONNECT_PROTOCOL_ERROR)) != 0 ||
2683 	    (r = sshpkt_put_cstring(ssh, buf)) != 0 ||
2684 	    (r = sshpkt_put_cstring(ssh, "")) != 0 ||
2685 	    (r = sshpkt_send(ssh)) != 0)
2686 		return r;
2687 	return 0;
2688 }
2689 
2690 /* roundup current message to pad bytes */
2691 int
2692 sshpkt_add_padding(struct ssh *ssh, u_char pad)
2693 {
2694 	ssh->state->extra_pad = pad;
2695 	return 0;
2696 }
2697