xref: /openssh-portable/packet.c (revision 4d28fa78)
1 /* $OpenBSD: packet.c,v 1.286 2019/06/28 13:35:04 deraadt 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 "compat.h"
81 #include "ssh2.h"
82 #include "cipher.h"
83 #include "sshkey.h"
84 #include "kex.h"
85 #include "digest.h"
86 #include "mac.h"
87 #include "log.h"
88 #include "canohost.h"
89 #include "misc.h"
90 #include "channels.h"
91 #include "ssh.h"
92 #include "packet.h"
93 #include "ssherr.h"
94 #include "sshbuf.h"
95 
96 #ifdef PACKET_DEBUG
97 #define DBG(x) x
98 #else
99 #define DBG(x)
100 #endif
101 
102 #define PACKET_MAX_SIZE (256 * 1024)
103 
104 struct packet_state {
105 	u_int32_t seqnr;
106 	u_int32_t packets;
107 	u_int64_t blocks;
108 	u_int64_t bytes;
109 };
110 
111 struct packet {
112 	TAILQ_ENTRY(packet) next;
113 	u_char type;
114 	struct sshbuf *payload;
115 };
116 
117 struct session_state {
118 	/*
119 	 * This variable contains the file descriptors used for
120 	 * communicating with the other side.  connection_in is used for
121 	 * reading; connection_out for writing.  These can be the same
122 	 * descriptor, in which case it is assumed to be a socket.
123 	 */
124 	int connection_in;
125 	int connection_out;
126 
127 	/* Protocol flags for the remote side. */
128 	u_int remote_protocol_flags;
129 
130 	/* Encryption context for receiving data.  Only used for decryption. */
131 	struct sshcipher_ctx *receive_context;
132 
133 	/* Encryption context for sending data.  Only used for encryption. */
134 	struct sshcipher_ctx *send_context;
135 
136 	/* Buffer for raw input data from the socket. */
137 	struct sshbuf *input;
138 
139 	/* Buffer for raw output data going to the socket. */
140 	struct sshbuf *output;
141 
142 	/* Buffer for the partial outgoing packet being constructed. */
143 	struct sshbuf *outgoing_packet;
144 
145 	/* Buffer for the incoming packet currently being processed. */
146 	struct sshbuf *incoming_packet;
147 
148 	/* Scratch buffer for packet compression/decompression. */
149 	struct sshbuf *compression_buffer;
150 
151 	/* Incoming/outgoing compression dictionaries */
152 	z_stream compression_in_stream;
153 	z_stream compression_out_stream;
154 	int compression_in_started;
155 	int compression_out_started;
156 	int compression_in_failures;
157 	int compression_out_failures;
158 
159 	/* default maximum packet size */
160 	u_int max_packet_size;
161 
162 	/* Flag indicating whether this module has been initialized. */
163 	int initialized;
164 
165 	/* Set to true if the connection is interactive. */
166 	int interactive_mode;
167 
168 	/* Set to true if we are the server side. */
169 	int server_side;
170 
171 	/* Set to true if we are authenticated. */
172 	int after_authentication;
173 
174 	int keep_alive_timeouts;
175 
176 	/* The maximum time that we will wait to send or receive a packet */
177 	int packet_timeout_ms;
178 
179 	/* Session key information for Encryption and MAC */
180 	struct newkeys *newkeys[MODE_MAX];
181 	struct packet_state p_read, p_send;
182 
183 	/* Volume-based rekeying */
184 	u_int64_t max_blocks_in, max_blocks_out, rekey_limit;
185 
186 	/* Time-based rekeying */
187 	u_int32_t rekey_interval;	/* how often in seconds */
188 	time_t rekey_time;	/* time of last rekeying */
189 
190 	/* roundup current message to extra_pad bytes */
191 	u_char extra_pad;
192 
193 	/* XXX discard incoming data after MAC error */
194 	u_int packet_discard;
195 	size_t packet_discard_mac_already;
196 	struct sshmac *packet_discard_mac;
197 
198 	/* Used in packet_read_poll2() */
199 	u_int packlen;
200 
201 	/* Used in packet_send2 */
202 	int rekeying;
203 
204 	/* Used in ssh_packet_send_mux() */
205 	int mux;
206 
207 	/* Used in packet_set_interactive */
208 	int set_interactive_called;
209 
210 	/* Used in packet_set_maxsize */
211 	int set_maxsize_called;
212 
213 	/* One-off warning about weak ciphers */
214 	int cipher_warning_done;
215 
216 	/* Hook for fuzzing inbound packets */
217 	ssh_packet_hook_fn *hook_in;
218 	void *hook_in_ctx;
219 
220 	TAILQ_HEAD(, packet) outgoing;
221 };
222 
223 struct ssh *
224 ssh_alloc_session_state(void)
225 {
226 	struct ssh *ssh = NULL;
227 	struct session_state *state = NULL;
228 
229 	if ((ssh = calloc(1, sizeof(*ssh))) == NULL ||
230 	    (state = calloc(1, sizeof(*state))) == NULL ||
231 	    (ssh->kex = kex_new()) == NULL ||
232 	    (state->input = sshbuf_new()) == NULL ||
233 	    (state->output = sshbuf_new()) == NULL ||
234 	    (state->outgoing_packet = sshbuf_new()) == NULL ||
235 	    (state->incoming_packet = sshbuf_new()) == NULL)
236 		goto fail;
237 	TAILQ_INIT(&state->outgoing);
238 	TAILQ_INIT(&ssh->private_keys);
239 	TAILQ_INIT(&ssh->public_keys);
240 	state->connection_in = -1;
241 	state->connection_out = -1;
242 	state->max_packet_size = 32768;
243 	state->packet_timeout_ms = -1;
244 	state->p_send.packets = state->p_read.packets = 0;
245 	state->initialized = 1;
246 	/*
247 	 * ssh_packet_send2() needs to queue packets until
248 	 * we've done the initial key exchange.
249 	 */
250 	state->rekeying = 1;
251 	ssh->state = state;
252 	return ssh;
253  fail:
254 	if (ssh) {
255 		kex_free(ssh->kex);
256 		free(ssh);
257 	}
258 	if (state) {
259 		sshbuf_free(state->input);
260 		sshbuf_free(state->output);
261 		sshbuf_free(state->incoming_packet);
262 		sshbuf_free(state->outgoing_packet);
263 		free(state);
264 	}
265 	return NULL;
266 }
267 
268 void
269 ssh_packet_set_input_hook(struct ssh *ssh, ssh_packet_hook_fn *hook, void *ctx)
270 {
271 	ssh->state->hook_in = hook;
272 	ssh->state->hook_in_ctx = ctx;
273 }
274 
275 /* Returns nonzero if rekeying is in progress */
276 int
277 ssh_packet_is_rekeying(struct ssh *ssh)
278 {
279 	return ssh->state->rekeying || ssh->kex->done == 0;
280 }
281 
282 /*
283  * Sets the descriptors used for communication.
284  */
285 struct ssh *
286 ssh_packet_set_connection(struct ssh *ssh, int fd_in, int fd_out)
287 {
288 	struct session_state *state;
289 	const struct sshcipher *none = cipher_by_name("none");
290 	int r;
291 
292 	if (none == NULL) {
293 		error("%s: cannot load cipher 'none'", __func__);
294 		return NULL;
295 	}
296 	if (ssh == NULL)
297 		ssh = ssh_alloc_session_state();
298 	if (ssh == NULL) {
299 		error("%s: could not allocate state", __func__);
300 		return NULL;
301 	}
302 	state = ssh->state;
303 	state->connection_in = fd_in;
304 	state->connection_out = fd_out;
305 	if ((r = cipher_init(&state->send_context, none,
306 	    (const u_char *)"", 0, NULL, 0, CIPHER_ENCRYPT)) != 0 ||
307 	    (r = cipher_init(&state->receive_context, none,
308 	    (const u_char *)"", 0, NULL, 0, CIPHER_DECRYPT)) != 0) {
309 		error("%s: cipher_init failed: %s", __func__, ssh_err(r));
310 		free(ssh); /* XXX need ssh_free_session_state? */
311 		return NULL;
312 	}
313 	state->newkeys[MODE_IN] = state->newkeys[MODE_OUT] = NULL;
314 	/*
315 	 * Cache the IP address of the remote connection for use in error
316 	 * messages that might be generated after the connection has closed.
317 	 */
318 	(void)ssh_remote_ipaddr(ssh);
319 	return ssh;
320 }
321 
322 void
323 ssh_packet_set_timeout(struct ssh *ssh, int timeout, int count)
324 {
325 	struct session_state *state = ssh->state;
326 
327 	if (timeout <= 0 || count <= 0) {
328 		state->packet_timeout_ms = -1;
329 		return;
330 	}
331 	if ((INT_MAX / 1000) / count < timeout)
332 		state->packet_timeout_ms = INT_MAX;
333 	else
334 		state->packet_timeout_ms = timeout * count * 1000;
335 }
336 
337 void
338 ssh_packet_set_mux(struct ssh *ssh)
339 {
340 	ssh->state->mux = 1;
341 	ssh->state->rekeying = 0;
342 }
343 
344 int
345 ssh_packet_get_mux(struct ssh *ssh)
346 {
347 	return ssh->state->mux;
348 }
349 
350 int
351 ssh_packet_set_log_preamble(struct ssh *ssh, const char *fmt, ...)
352 {
353 	va_list args;
354 	int r;
355 
356 	free(ssh->log_preamble);
357 	if (fmt == NULL)
358 		ssh->log_preamble = NULL;
359 	else {
360 		va_start(args, fmt);
361 		r = vasprintf(&ssh->log_preamble, fmt, args);
362 		va_end(args);
363 		if (r < 0 || ssh->log_preamble == NULL)
364 			return SSH_ERR_ALLOC_FAIL;
365 	}
366 	return 0;
367 }
368 
369 int
370 ssh_packet_stop_discard(struct ssh *ssh)
371 {
372 	struct session_state *state = ssh->state;
373 	int r;
374 
375 	if (state->packet_discard_mac) {
376 		char buf[1024];
377 		size_t dlen = PACKET_MAX_SIZE;
378 
379 		if (dlen > state->packet_discard_mac_already)
380 			dlen -= state->packet_discard_mac_already;
381 		memset(buf, 'a', sizeof(buf));
382 		while (sshbuf_len(state->incoming_packet) < dlen)
383 			if ((r = sshbuf_put(state->incoming_packet, buf,
384 			    sizeof(buf))) != 0)
385 				return r;
386 		(void) mac_compute(state->packet_discard_mac,
387 		    state->p_read.seqnr,
388 		    sshbuf_ptr(state->incoming_packet), dlen,
389 		    NULL, 0);
390 	}
391 	logit("Finished discarding for %.200s port %d",
392 	    ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
393 	return SSH_ERR_MAC_INVALID;
394 }
395 
396 static int
397 ssh_packet_start_discard(struct ssh *ssh, struct sshenc *enc,
398     struct sshmac *mac, size_t mac_already, u_int discard)
399 {
400 	struct session_state *state = ssh->state;
401 	int r;
402 
403 	if (enc == NULL || !cipher_is_cbc(enc->cipher) || (mac && mac->etm)) {
404 		if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0)
405 			return r;
406 		return SSH_ERR_MAC_INVALID;
407 	}
408 	/*
409 	 * Record number of bytes over which the mac has already
410 	 * been computed in order to minimize timing attacks.
411 	 */
412 	if (mac && mac->enabled) {
413 		state->packet_discard_mac = mac;
414 		state->packet_discard_mac_already = mac_already;
415 	}
416 	if (sshbuf_len(state->input) >= discard)
417 		return ssh_packet_stop_discard(ssh);
418 	state->packet_discard = discard - sshbuf_len(state->input);
419 	return 0;
420 }
421 
422 /* Returns 1 if remote host is connected via socket, 0 if not. */
423 
424 int
425 ssh_packet_connection_is_on_socket(struct ssh *ssh)
426 {
427 	struct session_state *state;
428 	struct sockaddr_storage from, to;
429 	socklen_t fromlen, tolen;
430 
431 	if (ssh == NULL || ssh->state == NULL)
432 		return 0;
433 
434 	state = ssh->state;
435 	if (state->connection_in == -1 || state->connection_out == -1)
436 		return 0;
437 	/* filedescriptors in and out are the same, so it's a socket */
438 	if (state->connection_in == state->connection_out)
439 		return 1;
440 	fromlen = sizeof(from);
441 	memset(&from, 0, sizeof(from));
442 	if (getpeername(state->connection_in, (struct sockaddr *)&from,
443 	    &fromlen) == -1)
444 		return 0;
445 	tolen = sizeof(to);
446 	memset(&to, 0, sizeof(to));
447 	if (getpeername(state->connection_out, (struct sockaddr *)&to,
448 	    &tolen) == -1)
449 		return 0;
450 	if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0)
451 		return 0;
452 	if (from.ss_family != AF_INET && from.ss_family != AF_INET6)
453 		return 0;
454 	return 1;
455 }
456 
457 void
458 ssh_packet_get_bytes(struct ssh *ssh, u_int64_t *ibytes, u_int64_t *obytes)
459 {
460 	if (ibytes)
461 		*ibytes = ssh->state->p_read.bytes;
462 	if (obytes)
463 		*obytes = ssh->state->p_send.bytes;
464 }
465 
466 int
467 ssh_packet_connection_af(struct ssh *ssh)
468 {
469 	struct sockaddr_storage to;
470 	socklen_t tolen = sizeof(to);
471 
472 	memset(&to, 0, sizeof(to));
473 	if (getsockname(ssh->state->connection_out, (struct sockaddr *)&to,
474 	    &tolen) == -1)
475 		return 0;
476 #ifdef IPV4_IN_IPV6
477 	if (to.ss_family == AF_INET6 &&
478 	    IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)&to)->sin6_addr))
479 		return AF_INET;
480 #endif
481 	return to.ss_family;
482 }
483 
484 /* Sets the connection into non-blocking mode. */
485 
486 void
487 ssh_packet_set_nonblocking(struct ssh *ssh)
488 {
489 	/* Set the socket into non-blocking mode. */
490 	set_nonblock(ssh->state->connection_in);
491 
492 	if (ssh->state->connection_out != ssh->state->connection_in)
493 		set_nonblock(ssh->state->connection_out);
494 }
495 
496 /* Returns the socket used for reading. */
497 
498 int
499 ssh_packet_get_connection_in(struct ssh *ssh)
500 {
501 	return ssh->state->connection_in;
502 }
503 
504 /* Returns the descriptor used for writing. */
505 
506 int
507 ssh_packet_get_connection_out(struct ssh *ssh)
508 {
509 	return ssh->state->connection_out;
510 }
511 
512 /*
513  * Returns the IP-address of the remote host as a string.  The returned
514  * string must not be freed.
515  */
516 
517 const char *
518 ssh_remote_ipaddr(struct ssh *ssh)
519 {
520 	int sock;
521 
522 	/* Check whether we have cached the ipaddr. */
523 	if (ssh->remote_ipaddr == NULL) {
524 		if (ssh_packet_connection_is_on_socket(ssh)) {
525 			sock = ssh->state->connection_in;
526 			ssh->remote_ipaddr = get_peer_ipaddr(sock);
527 			ssh->remote_port = get_peer_port(sock);
528 			ssh->local_ipaddr = get_local_ipaddr(sock);
529 			ssh->local_port = get_local_port(sock);
530 		} else {
531 			ssh->remote_ipaddr = strdup("UNKNOWN");
532 			ssh->remote_port = 65535;
533 			ssh->local_ipaddr = strdup("UNKNOWN");
534 			ssh->local_port = 65535;
535 		}
536 	}
537 	return ssh->remote_ipaddr;
538 }
539 
540 /* Returns the port number of the remote host. */
541 
542 int
543 ssh_remote_port(struct ssh *ssh)
544 {
545 	(void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */
546 	return ssh->remote_port;
547 }
548 
549 /*
550  * Returns the IP-address of the local host as a string.  The returned
551  * string must not be freed.
552  */
553 
554 const char *
555 ssh_local_ipaddr(struct ssh *ssh)
556 {
557 	(void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */
558 	return ssh->local_ipaddr;
559 }
560 
561 /* Returns the port number of the local host. */
562 
563 int
564 ssh_local_port(struct ssh *ssh)
565 {
566 	(void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */
567 	return ssh->local_port;
568 }
569 
570 /* Returns the routing domain of the input socket, or NULL if unavailable */
571 const char *
572 ssh_packet_rdomain_in(struct ssh *ssh)
573 {
574 	if (ssh->rdomain_in != NULL)
575 		return ssh->rdomain_in;
576 	if (!ssh_packet_connection_is_on_socket(ssh))
577 		return NULL;
578 	ssh->rdomain_in = get_rdomain(ssh->state->connection_in);
579 	return ssh->rdomain_in;
580 }
581 
582 /* Closes the connection and clears and frees internal data structures. */
583 
584 static void
585 ssh_packet_close_internal(struct ssh *ssh, int do_close)
586 {
587 	struct session_state *state = ssh->state;
588 	u_int mode;
589 
590 	if (!state->initialized)
591 		return;
592 	state->initialized = 0;
593 	if (do_close) {
594 		if (state->connection_in == state->connection_out) {
595 			close(state->connection_out);
596 		} else {
597 			close(state->connection_in);
598 			close(state->connection_out);
599 		}
600 	}
601 	sshbuf_free(state->input);
602 	sshbuf_free(state->output);
603 	sshbuf_free(state->outgoing_packet);
604 	sshbuf_free(state->incoming_packet);
605 	for (mode = 0; mode < MODE_MAX; mode++) {
606 		kex_free_newkeys(state->newkeys[mode]);	/* current keys */
607 		state->newkeys[mode] = NULL;
608 		ssh_clear_newkeys(ssh, mode);		/* next keys */
609 	}
610 	/* compression state is in shared mem, so we can only release it once */
611 	if (do_close && state->compression_buffer) {
612 		sshbuf_free(state->compression_buffer);
613 		if (state->compression_out_started) {
614 			z_streamp stream = &state->compression_out_stream;
615 			debug("compress outgoing: "
616 			    "raw data %llu, compressed %llu, factor %.2f",
617 				(unsigned long long)stream->total_in,
618 				(unsigned long long)stream->total_out,
619 				stream->total_in == 0 ? 0.0 :
620 				(double) stream->total_out / stream->total_in);
621 			if (state->compression_out_failures == 0)
622 				deflateEnd(stream);
623 		}
624 		if (state->compression_in_started) {
625 			z_streamp stream = &state->compression_in_stream;
626 			debug("compress incoming: "
627 			    "raw data %llu, compressed %llu, factor %.2f",
628 			    (unsigned long long)stream->total_out,
629 			    (unsigned long long)stream->total_in,
630 			    stream->total_out == 0 ? 0.0 :
631 			    (double) stream->total_in / stream->total_out);
632 			if (state->compression_in_failures == 0)
633 				inflateEnd(stream);
634 		}
635 	}
636 	cipher_free(state->send_context);
637 	cipher_free(state->receive_context);
638 	state->send_context = state->receive_context = NULL;
639 	if (do_close) {
640 		free(ssh->local_ipaddr);
641 		ssh->local_ipaddr = NULL;
642 		free(ssh->remote_ipaddr);
643 		ssh->remote_ipaddr = NULL;
644 		free(ssh->state);
645 		ssh->state = NULL;
646 	}
647 }
648 
649 void
650 ssh_packet_close(struct ssh *ssh)
651 {
652 	ssh_packet_close_internal(ssh, 1);
653 }
654 
655 void
656 ssh_packet_clear_keys(struct ssh *ssh)
657 {
658 	ssh_packet_close_internal(ssh, 0);
659 }
660 
661 /* Sets remote side protocol flags. */
662 
663 void
664 ssh_packet_set_protocol_flags(struct ssh *ssh, u_int protocol_flags)
665 {
666 	ssh->state->remote_protocol_flags = protocol_flags;
667 }
668 
669 /* Returns the remote protocol flags set earlier by the above function. */
670 
671 u_int
672 ssh_packet_get_protocol_flags(struct ssh *ssh)
673 {
674 	return ssh->state->remote_protocol_flags;
675 }
676 
677 /*
678  * Starts packet compression from the next packet on in both directions.
679  * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip.
680  */
681 
682 static int
683 ssh_packet_init_compression(struct ssh *ssh)
684 {
685 	if (!ssh->state->compression_buffer &&
686 	   ((ssh->state->compression_buffer = sshbuf_new()) == NULL))
687 		return SSH_ERR_ALLOC_FAIL;
688 	return 0;
689 }
690 
691 static int
692 start_compression_out(struct ssh *ssh, int level)
693 {
694 	if (level < 1 || level > 9)
695 		return SSH_ERR_INVALID_ARGUMENT;
696 	debug("Enabling compression at level %d.", level);
697 	if (ssh->state->compression_out_started == 1)
698 		deflateEnd(&ssh->state->compression_out_stream);
699 	switch (deflateInit(&ssh->state->compression_out_stream, level)) {
700 	case Z_OK:
701 		ssh->state->compression_out_started = 1;
702 		break;
703 	case Z_MEM_ERROR:
704 		return SSH_ERR_ALLOC_FAIL;
705 	default:
706 		return SSH_ERR_INTERNAL_ERROR;
707 	}
708 	return 0;
709 }
710 
711 static int
712 start_compression_in(struct ssh *ssh)
713 {
714 	if (ssh->state->compression_in_started == 1)
715 		inflateEnd(&ssh->state->compression_in_stream);
716 	switch (inflateInit(&ssh->state->compression_in_stream)) {
717 	case Z_OK:
718 		ssh->state->compression_in_started = 1;
719 		break;
720 	case Z_MEM_ERROR:
721 		return SSH_ERR_ALLOC_FAIL;
722 	default:
723 		return SSH_ERR_INTERNAL_ERROR;
724 	}
725 	return 0;
726 }
727 
728 /* XXX remove need for separate compression buffer */
729 static int
730 compress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out)
731 {
732 	u_char buf[4096];
733 	int r, status;
734 
735 	if (ssh->state->compression_out_started != 1)
736 		return SSH_ERR_INTERNAL_ERROR;
737 
738 	/* This case is not handled below. */
739 	if (sshbuf_len(in) == 0)
740 		return 0;
741 
742 	/* Input is the contents of the input buffer. */
743 	if ((ssh->state->compression_out_stream.next_in =
744 	    sshbuf_mutable_ptr(in)) == NULL)
745 		return SSH_ERR_INTERNAL_ERROR;
746 	ssh->state->compression_out_stream.avail_in = sshbuf_len(in);
747 
748 	/* Loop compressing until deflate() returns with avail_out != 0. */
749 	do {
750 		/* Set up fixed-size output buffer. */
751 		ssh->state->compression_out_stream.next_out = buf;
752 		ssh->state->compression_out_stream.avail_out = sizeof(buf);
753 
754 		/* Compress as much data into the buffer as possible. */
755 		status = deflate(&ssh->state->compression_out_stream,
756 		    Z_PARTIAL_FLUSH);
757 		switch (status) {
758 		case Z_MEM_ERROR:
759 			return SSH_ERR_ALLOC_FAIL;
760 		case Z_OK:
761 			/* Append compressed data to output_buffer. */
762 			if ((r = sshbuf_put(out, buf, sizeof(buf) -
763 			    ssh->state->compression_out_stream.avail_out)) != 0)
764 				return r;
765 			break;
766 		case Z_STREAM_ERROR:
767 		default:
768 			ssh->state->compression_out_failures++;
769 			return SSH_ERR_INVALID_FORMAT;
770 		}
771 	} while (ssh->state->compression_out_stream.avail_out == 0);
772 	return 0;
773 }
774 
775 static int
776 uncompress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out)
777 {
778 	u_char buf[4096];
779 	int r, status;
780 
781 	if (ssh->state->compression_in_started != 1)
782 		return SSH_ERR_INTERNAL_ERROR;
783 
784 	if ((ssh->state->compression_in_stream.next_in =
785 	    sshbuf_mutable_ptr(in)) == NULL)
786 		return SSH_ERR_INTERNAL_ERROR;
787 	ssh->state->compression_in_stream.avail_in = sshbuf_len(in);
788 
789 	for (;;) {
790 		/* Set up fixed-size output buffer. */
791 		ssh->state->compression_in_stream.next_out = buf;
792 		ssh->state->compression_in_stream.avail_out = sizeof(buf);
793 
794 		status = inflate(&ssh->state->compression_in_stream,
795 		    Z_PARTIAL_FLUSH);
796 		switch (status) {
797 		case Z_OK:
798 			if ((r = sshbuf_put(out, buf, sizeof(buf) -
799 			    ssh->state->compression_in_stream.avail_out)) != 0)
800 				return r;
801 			break;
802 		case Z_BUF_ERROR:
803 			/*
804 			 * Comments in zlib.h say that we should keep calling
805 			 * inflate() until we get an error.  This appears to
806 			 * be the error that we get.
807 			 */
808 			return 0;
809 		case Z_DATA_ERROR:
810 			return SSH_ERR_INVALID_FORMAT;
811 		case Z_MEM_ERROR:
812 			return SSH_ERR_ALLOC_FAIL;
813 		case Z_STREAM_ERROR:
814 		default:
815 			ssh->state->compression_in_failures++;
816 			return SSH_ERR_INTERNAL_ERROR;
817 		}
818 	}
819 	/* NOTREACHED */
820 }
821 
822 void
823 ssh_clear_newkeys(struct ssh *ssh, int mode)
824 {
825 	if (ssh->kex && ssh->kex->newkeys[mode]) {
826 		kex_free_newkeys(ssh->kex->newkeys[mode]);
827 		ssh->kex->newkeys[mode] = NULL;
828 	}
829 }
830 
831 int
832 ssh_set_newkeys(struct ssh *ssh, int mode)
833 {
834 	struct session_state *state = ssh->state;
835 	struct sshenc *enc;
836 	struct sshmac *mac;
837 	struct sshcomp *comp;
838 	struct sshcipher_ctx **ccp;
839 	struct packet_state *ps;
840 	u_int64_t *max_blocks;
841 	const char *wmsg;
842 	int r, crypt_type;
843 	const char *dir = mode == MODE_OUT ? "out" : "in";
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("%s: rekeying %s, input %llu bytes %llu blocks, "
860 		   "output %llu bytes %llu blocks", __func__, dir,
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("%s: cipher_init_context: %s", __func__, dir));
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 %s after %llu blocks", dir,
924 	    (unsigned long long)*max_blocks);
925 	return 0;
926 }
927 
928 #define MAX_PACKETS	(1U<<31)
929 static int
930 ssh_packet_need_rekeying(struct ssh *ssh, u_int outbound_packet_len)
931 {
932 	struct session_state *state = ssh->state;
933 	u_int32_t out_blocks;
934 
935 	/* XXX client can't cope with rekeying pre-auth */
936 	if (!state->after_authentication)
937 		return 0;
938 
939 	/* Haven't keyed yet or KEX in progress. */
940 	if (ssh_packet_is_rekeying(ssh))
941 		return 0;
942 
943 	/* Peer can't rekey */
944 	if (ssh->compat & SSH_BUG_NOREKEY)
945 		return 0;
946 
947 	/*
948 	 * Permit one packet in or out per rekey - this allows us to
949 	 * make progress when rekey limits are very small.
950 	 */
951 	if (state->p_send.packets == 0 && state->p_read.packets == 0)
952 		return 0;
953 
954 	/* Time-based rekeying */
955 	if (state->rekey_interval != 0 &&
956 	    (int64_t)state->rekey_time + state->rekey_interval <= monotime())
957 		return 1;
958 
959 	/*
960 	 * Always rekey when MAX_PACKETS sent in either direction
961 	 * As per RFC4344 section 3.1 we do this after 2^31 packets.
962 	 */
963 	if (state->p_send.packets > MAX_PACKETS ||
964 	    state->p_read.packets > MAX_PACKETS)
965 		return 1;
966 
967 	/* Rekey after (cipher-specific) maximum blocks */
968 	out_blocks = ROUNDUP(outbound_packet_len,
969 	    state->newkeys[MODE_OUT]->enc.block_size);
970 	return (state->max_blocks_out &&
971 	    (state->p_send.blocks + out_blocks > state->max_blocks_out)) ||
972 	    (state->max_blocks_in &&
973 	    (state->p_read.blocks > state->max_blocks_in));
974 }
975 
976 /*
977  * Delayed compression for SSH2 is enabled after authentication:
978  * This happens on the server side after a SSH2_MSG_USERAUTH_SUCCESS is sent,
979  * and on the client side after a SSH2_MSG_USERAUTH_SUCCESS is received.
980  */
981 static int
982 ssh_packet_enable_delayed_compress(struct ssh *ssh)
983 {
984 	struct session_state *state = ssh->state;
985 	struct sshcomp *comp = NULL;
986 	int r, mode;
987 
988 	/*
989 	 * Remember that we are past the authentication step, so rekeying
990 	 * with COMP_DELAYED will turn on compression immediately.
991 	 */
992 	state->after_authentication = 1;
993 	for (mode = 0; mode < MODE_MAX; mode++) {
994 		/* protocol error: USERAUTH_SUCCESS received before NEWKEYS */
995 		if (state->newkeys[mode] == NULL)
996 			continue;
997 		comp = &state->newkeys[mode]->comp;
998 		if (comp && !comp->enabled && comp->type == COMP_DELAYED) {
999 			if ((r = ssh_packet_init_compression(ssh)) != 0)
1000 				return r;
1001 			if (mode == MODE_OUT) {
1002 				if ((r = start_compression_out(ssh, 6)) != 0)
1003 					return r;
1004 			} else {
1005 				if ((r = start_compression_in(ssh)) != 0)
1006 					return r;
1007 			}
1008 			comp->enabled = 1;
1009 		}
1010 	}
1011 	return 0;
1012 }
1013 
1014 /* Used to mute debug logging for noisy packet types */
1015 int
1016 ssh_packet_log_type(u_char type)
1017 {
1018 	switch (type) {
1019 	case SSH2_MSG_CHANNEL_DATA:
1020 	case SSH2_MSG_CHANNEL_EXTENDED_DATA:
1021 	case SSH2_MSG_CHANNEL_WINDOW_ADJUST:
1022 		return 0;
1023 	default:
1024 		return 1;
1025 	}
1026 }
1027 
1028 /*
1029  * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue)
1030  */
1031 int
1032 ssh_packet_send2_wrapped(struct ssh *ssh)
1033 {
1034 	struct session_state *state = ssh->state;
1035 	u_char type, *cp, macbuf[SSH_DIGEST_MAX_LENGTH];
1036 	u_char tmp, padlen, pad = 0;
1037 	u_int authlen = 0, aadlen = 0;
1038 	u_int len;
1039 	struct sshenc *enc   = NULL;
1040 	struct sshmac *mac   = NULL;
1041 	struct sshcomp *comp = NULL;
1042 	int r, block_size;
1043 
1044 	if (state->newkeys[MODE_OUT] != NULL) {
1045 		enc  = &state->newkeys[MODE_OUT]->enc;
1046 		mac  = &state->newkeys[MODE_OUT]->mac;
1047 		comp = &state->newkeys[MODE_OUT]->comp;
1048 		/* disable mac for authenticated encryption */
1049 		if ((authlen = cipher_authlen(enc->cipher)) != 0)
1050 			mac = NULL;
1051 	}
1052 	block_size = enc ? enc->block_size : 8;
1053 	aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0;
1054 
1055 	type = (sshbuf_ptr(state->outgoing_packet))[5];
1056 	if (ssh_packet_log_type(type))
1057 		debug3("send packet: type %u", type);
1058 #ifdef PACKET_DEBUG
1059 	fprintf(stderr, "plain:     ");
1060 	sshbuf_dump(state->outgoing_packet, stderr);
1061 #endif
1062 
1063 	if (comp && comp->enabled) {
1064 		len = sshbuf_len(state->outgoing_packet);
1065 		/* skip header, compress only payload */
1066 		if ((r = sshbuf_consume(state->outgoing_packet, 5)) != 0)
1067 			goto out;
1068 		sshbuf_reset(state->compression_buffer);
1069 		if ((r = compress_buffer(ssh, state->outgoing_packet,
1070 		    state->compression_buffer)) != 0)
1071 			goto out;
1072 		sshbuf_reset(state->outgoing_packet);
1073 		if ((r = sshbuf_put(state->outgoing_packet,
1074 		    "\0\0\0\0\0", 5)) != 0 ||
1075 		    (r = sshbuf_putb(state->outgoing_packet,
1076 		    state->compression_buffer)) != 0)
1077 			goto out;
1078 		DBG(debug("compression: raw %d compressed %zd", len,
1079 		    sshbuf_len(state->outgoing_packet)));
1080 	}
1081 
1082 	/* sizeof (packet_len + pad_len + payload) */
1083 	len = sshbuf_len(state->outgoing_packet);
1084 
1085 	/*
1086 	 * calc size of padding, alloc space, get random data,
1087 	 * minimum padding is 4 bytes
1088 	 */
1089 	len -= aadlen; /* packet length is not encrypted for EtM modes */
1090 	padlen = block_size - (len % block_size);
1091 	if (padlen < 4)
1092 		padlen += block_size;
1093 	if (state->extra_pad) {
1094 		tmp = state->extra_pad;
1095 		state->extra_pad =
1096 		    ROUNDUP(state->extra_pad, block_size);
1097 		/* check if roundup overflowed */
1098 		if (state->extra_pad < tmp)
1099 			return SSH_ERR_INVALID_ARGUMENT;
1100 		tmp = (len + padlen) % state->extra_pad;
1101 		/* Check whether pad calculation below will underflow */
1102 		if (tmp > state->extra_pad)
1103 			return SSH_ERR_INVALID_ARGUMENT;
1104 		pad = state->extra_pad - tmp;
1105 		DBG(debug3("%s: adding %d (len %d padlen %d extra_pad %d)",
1106 		    __func__, pad, len, padlen, state->extra_pad));
1107 		tmp = padlen;
1108 		padlen += pad;
1109 		/* Check whether padlen calculation overflowed */
1110 		if (padlen < tmp)
1111 			return SSH_ERR_INVALID_ARGUMENT; /* overflow */
1112 		state->extra_pad = 0;
1113 	}
1114 	if ((r = sshbuf_reserve(state->outgoing_packet, padlen, &cp)) != 0)
1115 		goto out;
1116 	if (enc && !cipher_ctx_is_plaintext(state->send_context)) {
1117 		/* random padding */
1118 		arc4random_buf(cp, padlen);
1119 	} else {
1120 		/* clear padding */
1121 		explicit_bzero(cp, padlen);
1122 	}
1123 	/* sizeof (packet_len + pad_len + payload + padding) */
1124 	len = sshbuf_len(state->outgoing_packet);
1125 	cp = sshbuf_mutable_ptr(state->outgoing_packet);
1126 	if (cp == NULL) {
1127 		r = SSH_ERR_INTERNAL_ERROR;
1128 		goto out;
1129 	}
1130 	/* packet_length includes payload, padding and padding length field */
1131 	POKE_U32(cp, len - 4);
1132 	cp[4] = padlen;
1133 	DBG(debug("send: len %d (includes padlen %d, aadlen %d)",
1134 	    len, padlen, aadlen));
1135 
1136 	/* compute MAC over seqnr and packet(length fields, payload, padding) */
1137 	if (mac && mac->enabled && !mac->etm) {
1138 		if ((r = mac_compute(mac, state->p_send.seqnr,
1139 		    sshbuf_ptr(state->outgoing_packet), len,
1140 		    macbuf, sizeof(macbuf))) != 0)
1141 			goto out;
1142 		DBG(debug("done calc MAC out #%d", state->p_send.seqnr));
1143 	}
1144 	/* encrypt packet and append to output buffer. */
1145 	if ((r = sshbuf_reserve(state->output,
1146 	    sshbuf_len(state->outgoing_packet) + authlen, &cp)) != 0)
1147 		goto out;
1148 	if ((r = cipher_crypt(state->send_context, state->p_send.seqnr, cp,
1149 	    sshbuf_ptr(state->outgoing_packet),
1150 	    len - aadlen, aadlen, authlen)) != 0)
1151 		goto out;
1152 	/* append unencrypted MAC */
1153 	if (mac && mac->enabled) {
1154 		if (mac->etm) {
1155 			/* EtM: compute mac over aadlen + cipher text */
1156 			if ((r = mac_compute(mac, state->p_send.seqnr,
1157 			    cp, len, macbuf, sizeof(macbuf))) != 0)
1158 				goto out;
1159 			DBG(debug("done calc MAC(EtM) out #%d",
1160 			    state->p_send.seqnr));
1161 		}
1162 		if ((r = sshbuf_put(state->output, macbuf, mac->mac_len)) != 0)
1163 			goto out;
1164 	}
1165 #ifdef PACKET_DEBUG
1166 	fprintf(stderr, "encrypted: ");
1167 	sshbuf_dump(state->output, stderr);
1168 #endif
1169 	/* increment sequence number for outgoing packets */
1170 	if (++state->p_send.seqnr == 0)
1171 		logit("outgoing seqnr wraps around");
1172 	if (++state->p_send.packets == 0)
1173 		if (!(ssh->compat & SSH_BUG_NOREKEY))
1174 			return SSH_ERR_NEED_REKEY;
1175 	state->p_send.blocks += len / block_size;
1176 	state->p_send.bytes += len;
1177 	sshbuf_reset(state->outgoing_packet);
1178 
1179 	if (type == SSH2_MSG_NEWKEYS)
1180 		r = ssh_set_newkeys(ssh, MODE_OUT);
1181 	else if (type == SSH2_MSG_USERAUTH_SUCCESS && state->server_side)
1182 		r = ssh_packet_enable_delayed_compress(ssh);
1183 	else
1184 		r = 0;
1185  out:
1186 	return r;
1187 }
1188 
1189 /* returns non-zero if the specified packet type is usec by KEX */
1190 static int
1191 ssh_packet_type_is_kex(u_char type)
1192 {
1193 	return
1194 	    type >= SSH2_MSG_TRANSPORT_MIN &&
1195 	    type <= SSH2_MSG_TRANSPORT_MAX &&
1196 	    type != SSH2_MSG_SERVICE_REQUEST &&
1197 	    type != SSH2_MSG_SERVICE_ACCEPT &&
1198 	    type != SSH2_MSG_EXT_INFO;
1199 }
1200 
1201 int
1202 ssh_packet_send2(struct ssh *ssh)
1203 {
1204 	struct session_state *state = ssh->state;
1205 	struct packet *p;
1206 	u_char type;
1207 	int r, need_rekey;
1208 
1209 	if (sshbuf_len(state->outgoing_packet) < 6)
1210 		return SSH_ERR_INTERNAL_ERROR;
1211 	type = sshbuf_ptr(state->outgoing_packet)[5];
1212 	need_rekey = !ssh_packet_type_is_kex(type) &&
1213 	    ssh_packet_need_rekeying(ssh, sshbuf_len(state->outgoing_packet));
1214 
1215 	/*
1216 	 * During rekeying we can only send key exchange messages.
1217 	 * Queue everything else.
1218 	 */
1219 	if ((need_rekey || state->rekeying) && !ssh_packet_type_is_kex(type)) {
1220 		if (need_rekey)
1221 			debug3("%s: rekex triggered", __func__);
1222 		debug("enqueue packet: %u", type);
1223 		p = calloc(1, sizeof(*p));
1224 		if (p == NULL)
1225 			return SSH_ERR_ALLOC_FAIL;
1226 		p->type = type;
1227 		p->payload = state->outgoing_packet;
1228 		TAILQ_INSERT_TAIL(&state->outgoing, p, next);
1229 		state->outgoing_packet = sshbuf_new();
1230 		if (state->outgoing_packet == NULL)
1231 			return SSH_ERR_ALLOC_FAIL;
1232 		if (need_rekey) {
1233 			/*
1234 			 * This packet triggered a rekey, so send the
1235 			 * KEXINIT now.
1236 			 * NB. reenters this function via kex_start_rekex().
1237 			 */
1238 			return kex_start_rekex(ssh);
1239 		}
1240 		return 0;
1241 	}
1242 
1243 	/* rekeying starts with sending KEXINIT */
1244 	if (type == SSH2_MSG_KEXINIT)
1245 		state->rekeying = 1;
1246 
1247 	if ((r = ssh_packet_send2_wrapped(ssh)) != 0)
1248 		return r;
1249 
1250 	/* after a NEWKEYS message we can send the complete queue */
1251 	if (type == SSH2_MSG_NEWKEYS) {
1252 		state->rekeying = 0;
1253 		state->rekey_time = monotime();
1254 		while ((p = TAILQ_FIRST(&state->outgoing))) {
1255 			type = p->type;
1256 			/*
1257 			 * If this packet triggers a rekex, then skip the
1258 			 * remaining packets in the queue for now.
1259 			 * NB. re-enters this function via kex_start_rekex.
1260 			 */
1261 			if (ssh_packet_need_rekeying(ssh,
1262 			    sshbuf_len(p->payload))) {
1263 				debug3("%s: queued packet triggered rekex",
1264 				    __func__);
1265 				return kex_start_rekex(ssh);
1266 			}
1267 			debug("dequeue packet: %u", type);
1268 			sshbuf_free(state->outgoing_packet);
1269 			state->outgoing_packet = p->payload;
1270 			TAILQ_REMOVE(&state->outgoing, p, next);
1271 			memset(p, 0, sizeof(*p));
1272 			free(p);
1273 			if ((r = ssh_packet_send2_wrapped(ssh)) != 0)
1274 				return r;
1275 		}
1276 	}
1277 	return 0;
1278 }
1279 
1280 /*
1281  * Waits until a packet has been received, and returns its type.  Note that
1282  * no other data is processed until this returns, so this function should not
1283  * be used during the interactive session.
1284  */
1285 
1286 int
1287 ssh_packet_read_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
1288 {
1289 	struct session_state *state = ssh->state;
1290 	int len, r, ms_remain;
1291 	fd_set *setp;
1292 	char buf[8192];
1293 	struct timeval timeout, start, *timeoutp = NULL;
1294 
1295 	DBG(debug("packet_read()"));
1296 
1297 	setp = calloc(howmany(state->connection_in + 1,
1298 	    NFDBITS), sizeof(fd_mask));
1299 	if (setp == NULL)
1300 		return SSH_ERR_ALLOC_FAIL;
1301 
1302 	/*
1303 	 * Since we are blocking, ensure that all written packets have
1304 	 * been sent.
1305 	 */
1306 	if ((r = ssh_packet_write_wait(ssh)) != 0)
1307 		goto out;
1308 
1309 	/* Stay in the loop until we have received a complete packet. */
1310 	for (;;) {
1311 		/* Try to read a packet from the buffer. */
1312 		r = ssh_packet_read_poll_seqnr(ssh, typep, seqnr_p);
1313 		if (r != 0)
1314 			break;
1315 		/* If we got a packet, return it. */
1316 		if (*typep != SSH_MSG_NONE)
1317 			break;
1318 		/*
1319 		 * Otherwise, wait for some data to arrive, add it to the
1320 		 * buffer, and try again.
1321 		 */
1322 		memset(setp, 0, howmany(state->connection_in + 1,
1323 		    NFDBITS) * sizeof(fd_mask));
1324 		FD_SET(state->connection_in, setp);
1325 
1326 		if (state->packet_timeout_ms > 0) {
1327 			ms_remain = state->packet_timeout_ms;
1328 			timeoutp = &timeout;
1329 		}
1330 		/* Wait for some data to arrive. */
1331 		for (;;) {
1332 			if (state->packet_timeout_ms != -1) {
1333 				ms_to_timeval(&timeout, ms_remain);
1334 				monotime_tv(&start);
1335 			}
1336 			if ((r = select(state->connection_in + 1, setp,
1337 			    NULL, NULL, timeoutp)) >= 0)
1338 				break;
1339 			if (errno != EAGAIN && errno != EINTR &&
1340 			    errno != EWOULDBLOCK) {
1341 				r = SSH_ERR_SYSTEM_ERROR;
1342 				goto out;
1343 			}
1344 			if (state->packet_timeout_ms == -1)
1345 				continue;
1346 			ms_subtract_diff(&start, &ms_remain);
1347 			if (ms_remain <= 0) {
1348 				r = 0;
1349 				break;
1350 			}
1351 		}
1352 		if (r == 0) {
1353 			r = SSH_ERR_CONN_TIMEOUT;
1354 			goto out;
1355 		}
1356 		/* Read data from the socket. */
1357 		len = read(state->connection_in, buf, sizeof(buf));
1358 		if (len == 0) {
1359 			r = SSH_ERR_CONN_CLOSED;
1360 			goto out;
1361 		}
1362 		if (len == -1) {
1363 			r = SSH_ERR_SYSTEM_ERROR;
1364 			goto out;
1365 		}
1366 
1367 		/* Append it to the buffer. */
1368 		if ((r = ssh_packet_process_incoming(ssh, buf, len)) != 0)
1369 			goto out;
1370 	}
1371  out:
1372 	free(setp);
1373 	return r;
1374 }
1375 
1376 int
1377 ssh_packet_read(struct ssh *ssh)
1378 {
1379 	u_char type;
1380 	int r;
1381 
1382 	if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0)
1383 		fatal("%s: %s", __func__, ssh_err(r));
1384 	return type;
1385 }
1386 
1387 /*
1388  * Waits until a packet has been received, verifies that its type matches
1389  * that given, and gives a fatal error and exits if there is a mismatch.
1390  */
1391 
1392 int
1393 ssh_packet_read_expect(struct ssh *ssh, u_int expected_type)
1394 {
1395 	int r;
1396 	u_char type;
1397 
1398 	if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0)
1399 		return r;
1400 	if (type != expected_type) {
1401 		if ((r = sshpkt_disconnect(ssh,
1402 		    "Protocol error: expected packet type %d, got %d",
1403 		    expected_type, type)) != 0)
1404 			return r;
1405 		return SSH_ERR_PROTOCOL_ERROR;
1406 	}
1407 	return 0;
1408 }
1409 
1410 static int
1411 ssh_packet_read_poll2_mux(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
1412 {
1413 	struct session_state *state = ssh->state;
1414 	const u_char *cp;
1415 	size_t need;
1416 	int r;
1417 
1418 	if (ssh->kex)
1419 		return SSH_ERR_INTERNAL_ERROR;
1420 	*typep = SSH_MSG_NONE;
1421 	cp = sshbuf_ptr(state->input);
1422 	if (state->packlen == 0) {
1423 		if (sshbuf_len(state->input) < 4 + 1)
1424 			return 0; /* packet is incomplete */
1425 		state->packlen = PEEK_U32(cp);
1426 		if (state->packlen < 4 + 1 ||
1427 		    state->packlen > PACKET_MAX_SIZE)
1428 			return SSH_ERR_MESSAGE_INCOMPLETE;
1429 	}
1430 	need = state->packlen + 4;
1431 	if (sshbuf_len(state->input) < need)
1432 		return 0; /* packet is incomplete */
1433 	sshbuf_reset(state->incoming_packet);
1434 	if ((r = sshbuf_put(state->incoming_packet, cp + 4,
1435 	    state->packlen)) != 0 ||
1436 	    (r = sshbuf_consume(state->input, need)) != 0 ||
1437 	    (r = sshbuf_get_u8(state->incoming_packet, NULL)) != 0 ||
1438 	    (r = sshbuf_get_u8(state->incoming_packet, typep)) != 0)
1439 		return r;
1440 	if (ssh_packet_log_type(*typep))
1441 		debug3("%s: type %u", __func__, *typep);
1442 	/* sshbuf_dump(state->incoming_packet, stderr); */
1443 	/* reset for next packet */
1444 	state->packlen = 0;
1445 	return r;
1446 }
1447 
1448 int
1449 ssh_packet_read_poll2(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
1450 {
1451 	struct session_state *state = ssh->state;
1452 	u_int padlen, need;
1453 	u_char *cp;
1454 	u_int maclen, aadlen = 0, authlen = 0, block_size;
1455 	struct sshenc *enc   = NULL;
1456 	struct sshmac *mac   = NULL;
1457 	struct sshcomp *comp = NULL;
1458 	int r;
1459 
1460 	if (state->mux)
1461 		return ssh_packet_read_poll2_mux(ssh, typep, seqnr_p);
1462 
1463 	*typep = SSH_MSG_NONE;
1464 
1465 	if (state->packet_discard)
1466 		return 0;
1467 
1468 	if (state->newkeys[MODE_IN] != NULL) {
1469 		enc  = &state->newkeys[MODE_IN]->enc;
1470 		mac  = &state->newkeys[MODE_IN]->mac;
1471 		comp = &state->newkeys[MODE_IN]->comp;
1472 		/* disable mac for authenticated encryption */
1473 		if ((authlen = cipher_authlen(enc->cipher)) != 0)
1474 			mac = NULL;
1475 	}
1476 	maclen = mac && mac->enabled ? mac->mac_len : 0;
1477 	block_size = enc ? enc->block_size : 8;
1478 	aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0;
1479 
1480 	if (aadlen && state->packlen == 0) {
1481 		if (cipher_get_length(state->receive_context,
1482 		    &state->packlen, state->p_read.seqnr,
1483 		    sshbuf_ptr(state->input), sshbuf_len(state->input)) != 0)
1484 			return 0;
1485 		if (state->packlen < 1 + 4 ||
1486 		    state->packlen > PACKET_MAX_SIZE) {
1487 #ifdef PACKET_DEBUG
1488 			sshbuf_dump(state->input, stderr);
1489 #endif
1490 			logit("Bad packet length %u.", state->packlen);
1491 			if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0)
1492 				return r;
1493 			return SSH_ERR_CONN_CORRUPT;
1494 		}
1495 		sshbuf_reset(state->incoming_packet);
1496 	} else if (state->packlen == 0) {
1497 		/*
1498 		 * check if input size is less than the cipher block size,
1499 		 * decrypt first block and extract length of incoming packet
1500 		 */
1501 		if (sshbuf_len(state->input) < block_size)
1502 			return 0;
1503 		sshbuf_reset(state->incoming_packet);
1504 		if ((r = sshbuf_reserve(state->incoming_packet, block_size,
1505 		    &cp)) != 0)
1506 			goto out;
1507 		if ((r = cipher_crypt(state->receive_context,
1508 		    state->p_send.seqnr, cp, sshbuf_ptr(state->input),
1509 		    block_size, 0, 0)) != 0)
1510 			goto out;
1511 		state->packlen = PEEK_U32(sshbuf_ptr(state->incoming_packet));
1512 		if (state->packlen < 1 + 4 ||
1513 		    state->packlen > PACKET_MAX_SIZE) {
1514 #ifdef PACKET_DEBUG
1515 			fprintf(stderr, "input: \n");
1516 			sshbuf_dump(state->input, stderr);
1517 			fprintf(stderr, "incoming_packet: \n");
1518 			sshbuf_dump(state->incoming_packet, stderr);
1519 #endif
1520 			logit("Bad packet length %u.", state->packlen);
1521 			return ssh_packet_start_discard(ssh, enc, mac, 0,
1522 			    PACKET_MAX_SIZE);
1523 		}
1524 		if ((r = sshbuf_consume(state->input, block_size)) != 0)
1525 			goto out;
1526 	}
1527 	DBG(debug("input: packet len %u", state->packlen+4));
1528 
1529 	if (aadlen) {
1530 		/* only the payload is encrypted */
1531 		need = state->packlen;
1532 	} else {
1533 		/*
1534 		 * the payload size and the payload are encrypted, but we
1535 		 * have a partial packet of block_size bytes
1536 		 */
1537 		need = 4 + state->packlen - block_size;
1538 	}
1539 	DBG(debug("partial packet: block %d, need %d, maclen %d, authlen %d,"
1540 	    " aadlen %d", block_size, need, maclen, authlen, aadlen));
1541 	if (need % block_size != 0) {
1542 		logit("padding error: need %d block %d mod %d",
1543 		    need, block_size, need % block_size);
1544 		return ssh_packet_start_discard(ssh, enc, mac, 0,
1545 		    PACKET_MAX_SIZE - block_size);
1546 	}
1547 	/*
1548 	 * check if the entire packet has been received and
1549 	 * decrypt into incoming_packet:
1550 	 * 'aadlen' bytes are unencrypted, but authenticated.
1551 	 * 'need' bytes are encrypted, followed by either
1552 	 * 'authlen' bytes of authentication tag or
1553 	 * 'maclen' bytes of message authentication code.
1554 	 */
1555 	if (sshbuf_len(state->input) < aadlen + need + authlen + maclen)
1556 		return 0; /* packet is incomplete */
1557 #ifdef PACKET_DEBUG
1558 	fprintf(stderr, "read_poll enc/full: ");
1559 	sshbuf_dump(state->input, stderr);
1560 #endif
1561 	/* EtM: check mac over encrypted input */
1562 	if (mac && mac->enabled && mac->etm) {
1563 		if ((r = mac_check(mac, state->p_read.seqnr,
1564 		    sshbuf_ptr(state->input), aadlen + need,
1565 		    sshbuf_ptr(state->input) + aadlen + need + authlen,
1566 		    maclen)) != 0) {
1567 			if (r == SSH_ERR_MAC_INVALID)
1568 				logit("Corrupted MAC on input.");
1569 			goto out;
1570 		}
1571 	}
1572 	if ((r = sshbuf_reserve(state->incoming_packet, aadlen + need,
1573 	    &cp)) != 0)
1574 		goto out;
1575 	if ((r = cipher_crypt(state->receive_context, state->p_read.seqnr, cp,
1576 	    sshbuf_ptr(state->input), need, aadlen, authlen)) != 0)
1577 		goto out;
1578 	if ((r = sshbuf_consume(state->input, aadlen + need + authlen)) != 0)
1579 		goto out;
1580 	if (mac && mac->enabled) {
1581 		/* Not EtM: check MAC over cleartext */
1582 		if (!mac->etm && (r = mac_check(mac, state->p_read.seqnr,
1583 		    sshbuf_ptr(state->incoming_packet),
1584 		    sshbuf_len(state->incoming_packet),
1585 		    sshbuf_ptr(state->input), maclen)) != 0) {
1586 			if (r != SSH_ERR_MAC_INVALID)
1587 				goto out;
1588 			logit("Corrupted MAC on input.");
1589 			if (need + block_size > PACKET_MAX_SIZE)
1590 				return SSH_ERR_INTERNAL_ERROR;
1591 			return ssh_packet_start_discard(ssh, enc, mac,
1592 			    sshbuf_len(state->incoming_packet),
1593 			    PACKET_MAX_SIZE - need - block_size);
1594 		}
1595 		/* Remove MAC from input buffer */
1596 		DBG(debug("MAC #%d ok", state->p_read.seqnr));
1597 		if ((r = sshbuf_consume(state->input, mac->mac_len)) != 0)
1598 			goto out;
1599 	}
1600 	if (seqnr_p != NULL)
1601 		*seqnr_p = state->p_read.seqnr;
1602 	if (++state->p_read.seqnr == 0)
1603 		logit("incoming seqnr wraps around");
1604 	if (++state->p_read.packets == 0)
1605 		if (!(ssh->compat & SSH_BUG_NOREKEY))
1606 			return SSH_ERR_NEED_REKEY;
1607 	state->p_read.blocks += (state->packlen + 4) / block_size;
1608 	state->p_read.bytes += state->packlen + 4;
1609 
1610 	/* get padlen */
1611 	padlen = sshbuf_ptr(state->incoming_packet)[4];
1612 	DBG(debug("input: padlen %d", padlen));
1613 	if (padlen < 4)	{
1614 		if ((r = sshpkt_disconnect(ssh,
1615 		    "Corrupted padlen %d on input.", padlen)) != 0 ||
1616 		    (r = ssh_packet_write_wait(ssh)) != 0)
1617 			return r;
1618 		return SSH_ERR_CONN_CORRUPT;
1619 	}
1620 
1621 	/* skip packet size + padlen, discard padding */
1622 	if ((r = sshbuf_consume(state->incoming_packet, 4 + 1)) != 0 ||
1623 	    ((r = sshbuf_consume_end(state->incoming_packet, padlen)) != 0))
1624 		goto out;
1625 
1626 	DBG(debug("input: len before de-compress %zd",
1627 	    sshbuf_len(state->incoming_packet)));
1628 	if (comp && comp->enabled) {
1629 		sshbuf_reset(state->compression_buffer);
1630 		if ((r = uncompress_buffer(ssh, state->incoming_packet,
1631 		    state->compression_buffer)) != 0)
1632 			goto out;
1633 		sshbuf_reset(state->incoming_packet);
1634 		if ((r = sshbuf_putb(state->incoming_packet,
1635 		    state->compression_buffer)) != 0)
1636 			goto out;
1637 		DBG(debug("input: len after de-compress %zd",
1638 		    sshbuf_len(state->incoming_packet)));
1639 	}
1640 	/*
1641 	 * get packet type, implies consume.
1642 	 * return length of payload (without type field)
1643 	 */
1644 	if ((r = sshbuf_get_u8(state->incoming_packet, typep)) != 0)
1645 		goto out;
1646 	if (ssh_packet_log_type(*typep))
1647 		debug3("receive packet: type %u", *typep);
1648 	if (*typep < SSH2_MSG_MIN || *typep >= SSH2_MSG_LOCAL_MIN) {
1649 		if ((r = sshpkt_disconnect(ssh,
1650 		    "Invalid ssh2 packet type: %d", *typep)) != 0 ||
1651 		    (r = ssh_packet_write_wait(ssh)) != 0)
1652 			return r;
1653 		return SSH_ERR_PROTOCOL_ERROR;
1654 	}
1655 	if (state->hook_in != NULL &&
1656 	    (r = state->hook_in(ssh, state->incoming_packet, typep,
1657 	    state->hook_in_ctx)) != 0)
1658 		return r;
1659 	if (*typep == SSH2_MSG_USERAUTH_SUCCESS && !state->server_side)
1660 		r = ssh_packet_enable_delayed_compress(ssh);
1661 	else
1662 		r = 0;
1663 #ifdef PACKET_DEBUG
1664 	fprintf(stderr, "read/plain[%d]:\r\n", *typep);
1665 	sshbuf_dump(state->incoming_packet, stderr);
1666 #endif
1667 	/* reset for next packet */
1668 	state->packlen = 0;
1669 
1670 	/* do we need to rekey? */
1671 	if (ssh_packet_need_rekeying(ssh, 0)) {
1672 		debug3("%s: rekex triggered", __func__);
1673 		if ((r = kex_start_rekex(ssh)) != 0)
1674 			return r;
1675 	}
1676  out:
1677 	return r;
1678 }
1679 
1680 int
1681 ssh_packet_read_poll_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
1682 {
1683 	struct session_state *state = ssh->state;
1684 	u_int reason, seqnr;
1685 	int r;
1686 	u_char *msg;
1687 
1688 	for (;;) {
1689 		msg = NULL;
1690 		r = ssh_packet_read_poll2(ssh, typep, seqnr_p);
1691 		if (r != 0)
1692 			return r;
1693 		if (*typep) {
1694 			state->keep_alive_timeouts = 0;
1695 			DBG(debug("received packet type %d", *typep));
1696 		}
1697 		switch (*typep) {
1698 		case SSH2_MSG_IGNORE:
1699 			debug3("Received SSH2_MSG_IGNORE");
1700 			break;
1701 		case SSH2_MSG_DEBUG:
1702 			if ((r = sshpkt_get_u8(ssh, NULL)) != 0 ||
1703 			    (r = sshpkt_get_string(ssh, &msg, NULL)) != 0 ||
1704 			    (r = sshpkt_get_string(ssh, NULL, NULL)) != 0) {
1705 				free(msg);
1706 				return r;
1707 			}
1708 			debug("Remote: %.900s", msg);
1709 			free(msg);
1710 			break;
1711 		case SSH2_MSG_DISCONNECT:
1712 			if ((r = sshpkt_get_u32(ssh, &reason)) != 0 ||
1713 			    (r = sshpkt_get_string(ssh, &msg, NULL)) != 0)
1714 				return r;
1715 			/* Ignore normal client exit notifications */
1716 			do_log2(ssh->state->server_side &&
1717 			    reason == SSH2_DISCONNECT_BY_APPLICATION ?
1718 			    SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_ERROR,
1719 			    "Received disconnect from %s port %d:"
1720 			    "%u: %.400s", ssh_remote_ipaddr(ssh),
1721 			    ssh_remote_port(ssh), reason, msg);
1722 			free(msg);
1723 			return SSH_ERR_DISCONNECTED;
1724 		case SSH2_MSG_UNIMPLEMENTED:
1725 			if ((r = sshpkt_get_u32(ssh, &seqnr)) != 0)
1726 				return r;
1727 			debug("Received SSH2_MSG_UNIMPLEMENTED for %u",
1728 			    seqnr);
1729 			break;
1730 		default:
1731 			return 0;
1732 		}
1733 	}
1734 }
1735 
1736 /*
1737  * Buffers the given amount of input characters.  This is intended to be used
1738  * together with packet_read_poll.
1739  */
1740 
1741 int
1742 ssh_packet_process_incoming(struct ssh *ssh, const char *buf, u_int len)
1743 {
1744 	struct session_state *state = ssh->state;
1745 	int r;
1746 
1747 	if (state->packet_discard) {
1748 		state->keep_alive_timeouts = 0; /* ?? */
1749 		if (len >= state->packet_discard) {
1750 			if ((r = ssh_packet_stop_discard(ssh)) != 0)
1751 				return r;
1752 		}
1753 		state->packet_discard -= len;
1754 		return 0;
1755 	}
1756 	if ((r = sshbuf_put(ssh->state->input, buf, len)) != 0)
1757 		return r;
1758 
1759 	return 0;
1760 }
1761 
1762 int
1763 ssh_packet_remaining(struct ssh *ssh)
1764 {
1765 	return sshbuf_len(ssh->state->incoming_packet);
1766 }
1767 
1768 /*
1769  * Sends a diagnostic message from the server to the client.  This message
1770  * can be sent at any time (but not while constructing another message). The
1771  * message is printed immediately, but only if the client is being executed
1772  * in verbose mode.  These messages are primarily intended to ease debugging
1773  * authentication problems.   The length of the formatted message must not
1774  * exceed 1024 bytes.  This will automatically call ssh_packet_write_wait.
1775  */
1776 void
1777 ssh_packet_send_debug(struct ssh *ssh, const char *fmt,...)
1778 {
1779 	char buf[1024];
1780 	va_list args;
1781 	int r;
1782 
1783 	if ((ssh->compat & SSH_BUG_DEBUG))
1784 		return;
1785 
1786 	va_start(args, fmt);
1787 	vsnprintf(buf, sizeof(buf), fmt, args);
1788 	va_end(args);
1789 
1790 	debug3("sending debug message: %s", buf);
1791 
1792 	if ((r = sshpkt_start(ssh, SSH2_MSG_DEBUG)) != 0 ||
1793 	    (r = sshpkt_put_u8(ssh, 0)) != 0 || /* always display */
1794 	    (r = sshpkt_put_cstring(ssh, buf)) != 0 ||
1795 	    (r = sshpkt_put_cstring(ssh, "")) != 0 ||
1796 	    (r = sshpkt_send(ssh)) != 0 ||
1797 	    (r = ssh_packet_write_wait(ssh)) != 0)
1798 		fatal("%s: %s", __func__, ssh_err(r));
1799 }
1800 
1801 void
1802 sshpkt_fmt_connection_id(struct ssh *ssh, char *s, size_t l)
1803 {
1804 	snprintf(s, l, "%.200s%s%s port %d",
1805 	    ssh->log_preamble ? ssh->log_preamble : "",
1806 	    ssh->log_preamble ? " " : "",
1807 	    ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
1808 }
1809 
1810 /*
1811  * Pretty-print connection-terminating errors and exit.
1812  */
1813 static void
1814 sshpkt_vfatal(struct ssh *ssh, int r, const char *fmt, va_list ap)
1815 {
1816 	char *tag = NULL, remote_id[512];
1817 
1818 	sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id));
1819 
1820 	switch (r) {
1821 	case SSH_ERR_CONN_CLOSED:
1822 		ssh_packet_clear_keys(ssh);
1823 		logdie("Connection closed by %s", remote_id);
1824 	case SSH_ERR_CONN_TIMEOUT:
1825 		ssh_packet_clear_keys(ssh);
1826 		logdie("Connection %s %s timed out",
1827 		    ssh->state->server_side ? "from" : "to", remote_id);
1828 	case SSH_ERR_DISCONNECTED:
1829 		ssh_packet_clear_keys(ssh);
1830 		logdie("Disconnected from %s", remote_id);
1831 	case SSH_ERR_SYSTEM_ERROR:
1832 		if (errno == ECONNRESET) {
1833 			ssh_packet_clear_keys(ssh);
1834 			logdie("Connection reset by %s", remote_id);
1835 		}
1836 		/* FALLTHROUGH */
1837 	case SSH_ERR_NO_CIPHER_ALG_MATCH:
1838 	case SSH_ERR_NO_MAC_ALG_MATCH:
1839 	case SSH_ERR_NO_COMPRESS_ALG_MATCH:
1840 	case SSH_ERR_NO_KEX_ALG_MATCH:
1841 	case SSH_ERR_NO_HOSTKEY_ALG_MATCH:
1842 		if (ssh && ssh->kex && ssh->kex->failed_choice) {
1843 			ssh_packet_clear_keys(ssh);
1844 			logdie("Unable to negotiate with %s: %s. "
1845 			    "Their offer: %s", remote_id, ssh_err(r),
1846 			    ssh->kex->failed_choice);
1847 		}
1848 		/* FALLTHROUGH */
1849 	default:
1850 		if (vasprintf(&tag, fmt, ap) == -1) {
1851 			ssh_packet_clear_keys(ssh);
1852 			logdie("%s: could not allocate failure message",
1853 			    __func__);
1854 		}
1855 		ssh_packet_clear_keys(ssh);
1856 		logdie("%s%sConnection %s %s: %s",
1857 		    tag != NULL ? tag : "", tag != NULL ? ": " : "",
1858 		    ssh->state->server_side ? "from" : "to",
1859 		    remote_id, ssh_err(r));
1860 	}
1861 }
1862 
1863 void
1864 sshpkt_fatal(struct ssh *ssh, int r, const char *fmt, ...)
1865 {
1866 	va_list ap;
1867 
1868 	va_start(ap, fmt);
1869 	sshpkt_vfatal(ssh, r, fmt, ap);
1870 	/* NOTREACHED */
1871 	va_end(ap);
1872 	logdie("%s: should have exited", __func__);
1873 }
1874 
1875 /*
1876  * Logs the error plus constructs and sends a disconnect packet, closes the
1877  * connection, and exits.  This function never returns. The error message
1878  * should not contain a newline.  The length of the formatted message must
1879  * not exceed 1024 bytes.
1880  */
1881 void
1882 ssh_packet_disconnect(struct ssh *ssh, const char *fmt,...)
1883 {
1884 	char buf[1024], remote_id[512];
1885 	va_list args;
1886 	static int disconnecting = 0;
1887 	int r;
1888 
1889 	if (disconnecting)	/* Guard against recursive invocations. */
1890 		fatal("packet_disconnect called recursively.");
1891 	disconnecting = 1;
1892 
1893 	/*
1894 	 * Format the message.  Note that the caller must make sure the
1895 	 * message is of limited size.
1896 	 */
1897 	sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id));
1898 	va_start(args, fmt);
1899 	vsnprintf(buf, sizeof(buf), fmt, args);
1900 	va_end(args);
1901 
1902 	/* Display the error locally */
1903 	logit("Disconnecting %s: %.100s", remote_id, buf);
1904 
1905 	/*
1906 	 * Send the disconnect message to the other side, and wait
1907 	 * for it to get sent.
1908 	 */
1909 	if ((r = sshpkt_disconnect(ssh, "%s", buf)) != 0)
1910 		sshpkt_fatal(ssh, r, "%s", __func__);
1911 
1912 	if ((r = ssh_packet_write_wait(ssh)) != 0)
1913 		sshpkt_fatal(ssh, r, "%s", __func__);
1914 
1915 	/* Close the connection. */
1916 	ssh_packet_close(ssh);
1917 	cleanup_exit(255);
1918 }
1919 
1920 /*
1921  * Checks if there is any buffered output, and tries to write some of
1922  * the output.
1923  */
1924 int
1925 ssh_packet_write_poll(struct ssh *ssh)
1926 {
1927 	struct session_state *state = ssh->state;
1928 	int len = sshbuf_len(state->output);
1929 	int r;
1930 
1931 	if (len > 0) {
1932 		len = write(state->connection_out,
1933 		    sshbuf_ptr(state->output), len);
1934 		if (len == -1) {
1935 			if (errno == EINTR || errno == EAGAIN ||
1936 			    errno == EWOULDBLOCK)
1937 				return 0;
1938 			return SSH_ERR_SYSTEM_ERROR;
1939 		}
1940 		if (len == 0)
1941 			return SSH_ERR_CONN_CLOSED;
1942 		if ((r = sshbuf_consume(state->output, len)) != 0)
1943 			return r;
1944 	}
1945 	return 0;
1946 }
1947 
1948 /*
1949  * Calls packet_write_poll repeatedly until all pending output data has been
1950  * written.
1951  */
1952 int
1953 ssh_packet_write_wait(struct ssh *ssh)
1954 {
1955 	fd_set *setp;
1956 	int ret, r, ms_remain = 0;
1957 	struct timeval start, timeout, *timeoutp = NULL;
1958 	struct session_state *state = ssh->state;
1959 
1960 	setp = calloc(howmany(state->connection_out + 1,
1961 	    NFDBITS), sizeof(fd_mask));
1962 	if (setp == NULL)
1963 		return SSH_ERR_ALLOC_FAIL;
1964 	if ((r = ssh_packet_write_poll(ssh)) != 0) {
1965 		free(setp);
1966 		return r;
1967 	}
1968 	while (ssh_packet_have_data_to_write(ssh)) {
1969 		memset(setp, 0, howmany(state->connection_out + 1,
1970 		    NFDBITS) * sizeof(fd_mask));
1971 		FD_SET(state->connection_out, setp);
1972 
1973 		if (state->packet_timeout_ms > 0) {
1974 			ms_remain = state->packet_timeout_ms;
1975 			timeoutp = &timeout;
1976 		}
1977 		for (;;) {
1978 			if (state->packet_timeout_ms != -1) {
1979 				ms_to_timeval(&timeout, ms_remain);
1980 				monotime_tv(&start);
1981 			}
1982 			if ((ret = select(state->connection_out + 1,
1983 			    NULL, setp, NULL, timeoutp)) >= 0)
1984 				break;
1985 			if (errno != EAGAIN && errno != EINTR &&
1986 			    errno != EWOULDBLOCK)
1987 				break;
1988 			if (state->packet_timeout_ms == -1)
1989 				continue;
1990 			ms_subtract_diff(&start, &ms_remain);
1991 			if (ms_remain <= 0) {
1992 				ret = 0;
1993 				break;
1994 			}
1995 		}
1996 		if (ret == 0) {
1997 			free(setp);
1998 			return SSH_ERR_CONN_TIMEOUT;
1999 		}
2000 		if ((r = ssh_packet_write_poll(ssh)) != 0) {
2001 			free(setp);
2002 			return r;
2003 		}
2004 	}
2005 	free(setp);
2006 	return 0;
2007 }
2008 
2009 /* Returns true if there is buffered data to write to the connection. */
2010 
2011 int
2012 ssh_packet_have_data_to_write(struct ssh *ssh)
2013 {
2014 	return sshbuf_len(ssh->state->output) != 0;
2015 }
2016 
2017 /* Returns true if there is not too much data to write to the connection. */
2018 
2019 int
2020 ssh_packet_not_very_much_data_to_write(struct ssh *ssh)
2021 {
2022 	if (ssh->state->interactive_mode)
2023 		return sshbuf_len(ssh->state->output) < 16384;
2024 	else
2025 		return sshbuf_len(ssh->state->output) < 128 * 1024;
2026 }
2027 
2028 void
2029 ssh_packet_set_tos(struct ssh *ssh, int tos)
2030 {
2031 #ifndef IP_TOS_IS_BROKEN
2032 	if (!ssh_packet_connection_is_on_socket(ssh) || tos == INT_MAX)
2033 		return;
2034 	switch (ssh_packet_connection_af(ssh)) {
2035 # ifdef IP_TOS
2036 	case AF_INET:
2037 		debug3("%s: set IP_TOS 0x%02x", __func__, tos);
2038 		if (setsockopt(ssh->state->connection_in,
2039 		    IPPROTO_IP, IP_TOS, &tos, sizeof(tos)) == -1)
2040 			error("setsockopt IP_TOS %d: %.100s:",
2041 			    tos, strerror(errno));
2042 		break;
2043 # endif /* IP_TOS */
2044 # ifdef IPV6_TCLASS
2045 	case AF_INET6:
2046 		debug3("%s: set IPV6_TCLASS 0x%02x", __func__, tos);
2047 		if (setsockopt(ssh->state->connection_in,
2048 		    IPPROTO_IPV6, IPV6_TCLASS, &tos, sizeof(tos)) == -1)
2049 			error("setsockopt IPV6_TCLASS %d: %.100s:",
2050 			    tos, strerror(errno));
2051 		break;
2052 # endif /* IPV6_TCLASS */
2053 	}
2054 #endif /* IP_TOS_IS_BROKEN */
2055 }
2056 
2057 /* Informs that the current session is interactive.  Sets IP flags for that. */
2058 
2059 void
2060 ssh_packet_set_interactive(struct ssh *ssh, int interactive, int qos_interactive, int qos_bulk)
2061 {
2062 	struct session_state *state = ssh->state;
2063 
2064 	if (state->set_interactive_called)
2065 		return;
2066 	state->set_interactive_called = 1;
2067 
2068 	/* Record that we are in interactive mode. */
2069 	state->interactive_mode = interactive;
2070 
2071 	/* Only set socket options if using a socket.  */
2072 	if (!ssh_packet_connection_is_on_socket(ssh))
2073 		return;
2074 	set_nodelay(state->connection_in);
2075 	ssh_packet_set_tos(ssh, interactive ? qos_interactive :
2076 	    qos_bulk);
2077 }
2078 
2079 /* Returns true if the current connection is interactive. */
2080 
2081 int
2082 ssh_packet_is_interactive(struct ssh *ssh)
2083 {
2084 	return ssh->state->interactive_mode;
2085 }
2086 
2087 int
2088 ssh_packet_set_maxsize(struct ssh *ssh, u_int s)
2089 {
2090 	struct session_state *state = ssh->state;
2091 
2092 	if (state->set_maxsize_called) {
2093 		logit("packet_set_maxsize: called twice: old %d new %d",
2094 		    state->max_packet_size, s);
2095 		return -1;
2096 	}
2097 	if (s < 4 * 1024 || s > 1024 * 1024) {
2098 		logit("packet_set_maxsize: bad size %d", s);
2099 		return -1;
2100 	}
2101 	state->set_maxsize_called = 1;
2102 	debug("packet_set_maxsize: setting to %d", s);
2103 	state->max_packet_size = s;
2104 	return s;
2105 }
2106 
2107 int
2108 ssh_packet_inc_alive_timeouts(struct ssh *ssh)
2109 {
2110 	return ++ssh->state->keep_alive_timeouts;
2111 }
2112 
2113 void
2114 ssh_packet_set_alive_timeouts(struct ssh *ssh, int ka)
2115 {
2116 	ssh->state->keep_alive_timeouts = ka;
2117 }
2118 
2119 u_int
2120 ssh_packet_get_maxsize(struct ssh *ssh)
2121 {
2122 	return ssh->state->max_packet_size;
2123 }
2124 
2125 void
2126 ssh_packet_set_rekey_limits(struct ssh *ssh, u_int64_t bytes, u_int32_t seconds)
2127 {
2128 	debug3("rekey after %llu bytes, %u seconds", (unsigned long long)bytes,
2129 	    (unsigned int)seconds);
2130 	ssh->state->rekey_limit = bytes;
2131 	ssh->state->rekey_interval = seconds;
2132 }
2133 
2134 time_t
2135 ssh_packet_get_rekey_timeout(struct ssh *ssh)
2136 {
2137 	time_t seconds;
2138 
2139 	seconds = ssh->state->rekey_time + ssh->state->rekey_interval -
2140 	    monotime();
2141 	return (seconds <= 0 ? 1 : seconds);
2142 }
2143 
2144 void
2145 ssh_packet_set_server(struct ssh *ssh)
2146 {
2147 	ssh->state->server_side = 1;
2148 	ssh->kex->server = 1; /* XXX unify? */
2149 }
2150 
2151 void
2152 ssh_packet_set_authenticated(struct ssh *ssh)
2153 {
2154 	ssh->state->after_authentication = 1;
2155 }
2156 
2157 void *
2158 ssh_packet_get_input(struct ssh *ssh)
2159 {
2160 	return (void *)ssh->state->input;
2161 }
2162 
2163 void *
2164 ssh_packet_get_output(struct ssh *ssh)
2165 {
2166 	return (void *)ssh->state->output;
2167 }
2168 
2169 /* Reset after_authentication and reset compression in post-auth privsep */
2170 static int
2171 ssh_packet_set_postauth(struct ssh *ssh)
2172 {
2173 	int r;
2174 
2175 	debug("%s: called", __func__);
2176 	/* This was set in net child, but is not visible in user child */
2177 	ssh->state->after_authentication = 1;
2178 	ssh->state->rekeying = 0;
2179 	if ((r = ssh_packet_enable_delayed_compress(ssh)) != 0)
2180 		return r;
2181 	return 0;
2182 }
2183 
2184 /* Packet state (de-)serialization for privsep */
2185 
2186 /* turn kex into a blob for packet state serialization */
2187 static int
2188 kex_to_blob(struct sshbuf *m, struct kex *kex)
2189 {
2190 	int r;
2191 
2192 	if ((r = sshbuf_put_string(m, kex->session_id,
2193 	    kex->session_id_len)) != 0 ||
2194 	    (r = sshbuf_put_u32(m, kex->we_need)) != 0 ||
2195 	    (r = sshbuf_put_cstring(m, kex->hostkey_alg)) != 0 ||
2196 	    (r = sshbuf_put_u32(m, kex->hostkey_type)) != 0 ||
2197 	    (r = sshbuf_put_u32(m, kex->hostkey_nid)) != 0 ||
2198 	    (r = sshbuf_put_u32(m, kex->kex_type)) != 0 ||
2199 	    (r = sshbuf_put_stringb(m, kex->my)) != 0 ||
2200 	    (r = sshbuf_put_stringb(m, kex->peer)) != 0 ||
2201 	    (r = sshbuf_put_stringb(m, kex->client_version)) != 0 ||
2202 	    (r = sshbuf_put_stringb(m, kex->server_version)) != 0 ||
2203 	    (r = sshbuf_put_u32(m, kex->flags)) != 0)
2204 		return r;
2205 	return 0;
2206 }
2207 
2208 /* turn key exchange results into a blob for packet state serialization */
2209 static int
2210 newkeys_to_blob(struct sshbuf *m, struct ssh *ssh, int mode)
2211 {
2212 	struct sshbuf *b;
2213 	struct sshcipher_ctx *cc;
2214 	struct sshcomp *comp;
2215 	struct sshenc *enc;
2216 	struct sshmac *mac;
2217 	struct newkeys *newkey;
2218 	int r;
2219 
2220 	if ((newkey = ssh->state->newkeys[mode]) == NULL)
2221 		return SSH_ERR_INTERNAL_ERROR;
2222 	enc = &newkey->enc;
2223 	mac = &newkey->mac;
2224 	comp = &newkey->comp;
2225 	cc = (mode == MODE_OUT) ? ssh->state->send_context :
2226 	    ssh->state->receive_context;
2227 	if ((r = cipher_get_keyiv(cc, enc->iv, enc->iv_len)) != 0)
2228 		return r;
2229 	if ((b = sshbuf_new()) == NULL)
2230 		return SSH_ERR_ALLOC_FAIL;
2231 	if ((r = sshbuf_put_cstring(b, enc->name)) != 0 ||
2232 	    (r = sshbuf_put_u32(b, enc->enabled)) != 0 ||
2233 	    (r = sshbuf_put_u32(b, enc->block_size)) != 0 ||
2234 	    (r = sshbuf_put_string(b, enc->key, enc->key_len)) != 0 ||
2235 	    (r = sshbuf_put_string(b, enc->iv, enc->iv_len)) != 0)
2236 		goto out;
2237 	if (cipher_authlen(enc->cipher) == 0) {
2238 		if ((r = sshbuf_put_cstring(b, mac->name)) != 0 ||
2239 		    (r = sshbuf_put_u32(b, mac->enabled)) != 0 ||
2240 		    (r = sshbuf_put_string(b, mac->key, mac->key_len)) != 0)
2241 			goto out;
2242 	}
2243 	if ((r = sshbuf_put_u32(b, comp->type)) != 0 ||
2244 	    (r = sshbuf_put_cstring(b, comp->name)) != 0)
2245 		goto out;
2246 	r = sshbuf_put_stringb(m, b);
2247  out:
2248 	sshbuf_free(b);
2249 	return r;
2250 }
2251 
2252 /* serialize packet state into a blob */
2253 int
2254 ssh_packet_get_state(struct ssh *ssh, struct sshbuf *m)
2255 {
2256 	struct session_state *state = ssh->state;
2257 	int r;
2258 
2259 	if ((r = kex_to_blob(m, ssh->kex)) != 0 ||
2260 	    (r = newkeys_to_blob(m, ssh, MODE_OUT)) != 0 ||
2261 	    (r = newkeys_to_blob(m, ssh, MODE_IN)) != 0 ||
2262 	    (r = sshbuf_put_u64(m, state->rekey_limit)) != 0 ||
2263 	    (r = sshbuf_put_u32(m, state->rekey_interval)) != 0 ||
2264 	    (r = sshbuf_put_u32(m, state->p_send.seqnr)) != 0 ||
2265 	    (r = sshbuf_put_u64(m, state->p_send.blocks)) != 0 ||
2266 	    (r = sshbuf_put_u32(m, state->p_send.packets)) != 0 ||
2267 	    (r = sshbuf_put_u64(m, state->p_send.bytes)) != 0 ||
2268 	    (r = sshbuf_put_u32(m, state->p_read.seqnr)) != 0 ||
2269 	    (r = sshbuf_put_u64(m, state->p_read.blocks)) != 0 ||
2270 	    (r = sshbuf_put_u32(m, state->p_read.packets)) != 0 ||
2271 	    (r = sshbuf_put_u64(m, state->p_read.bytes)) != 0 ||
2272 	    (r = sshbuf_put_stringb(m, state->input)) != 0 ||
2273 	    (r = sshbuf_put_stringb(m, state->output)) != 0)
2274 		return r;
2275 
2276 	return 0;
2277 }
2278 
2279 /* restore key exchange results from blob for packet state de-serialization */
2280 static int
2281 newkeys_from_blob(struct sshbuf *m, struct ssh *ssh, int mode)
2282 {
2283 	struct sshbuf *b = NULL;
2284 	struct sshcomp *comp;
2285 	struct sshenc *enc;
2286 	struct sshmac *mac;
2287 	struct newkeys *newkey = NULL;
2288 	size_t keylen, ivlen, maclen;
2289 	int r;
2290 
2291 	if ((newkey = calloc(1, sizeof(*newkey))) == NULL) {
2292 		r = SSH_ERR_ALLOC_FAIL;
2293 		goto out;
2294 	}
2295 	if ((r = sshbuf_froms(m, &b)) != 0)
2296 		goto out;
2297 #ifdef DEBUG_PK
2298 	sshbuf_dump(b, stderr);
2299 #endif
2300 	enc = &newkey->enc;
2301 	mac = &newkey->mac;
2302 	comp = &newkey->comp;
2303 
2304 	if ((r = sshbuf_get_cstring(b, &enc->name, NULL)) != 0 ||
2305 	    (r = sshbuf_get_u32(b, (u_int *)&enc->enabled)) != 0 ||
2306 	    (r = sshbuf_get_u32(b, &enc->block_size)) != 0 ||
2307 	    (r = sshbuf_get_string(b, &enc->key, &keylen)) != 0 ||
2308 	    (r = sshbuf_get_string(b, &enc->iv, &ivlen)) != 0)
2309 		goto out;
2310 	if ((enc->cipher = cipher_by_name(enc->name)) == NULL) {
2311 		r = SSH_ERR_INVALID_FORMAT;
2312 		goto out;
2313 	}
2314 	if (cipher_authlen(enc->cipher) == 0) {
2315 		if ((r = sshbuf_get_cstring(b, &mac->name, NULL)) != 0)
2316 			goto out;
2317 		if ((r = mac_setup(mac, mac->name)) != 0)
2318 			goto out;
2319 		if ((r = sshbuf_get_u32(b, (u_int *)&mac->enabled)) != 0 ||
2320 		    (r = sshbuf_get_string(b, &mac->key, &maclen)) != 0)
2321 			goto out;
2322 		if (maclen > mac->key_len) {
2323 			r = SSH_ERR_INVALID_FORMAT;
2324 			goto out;
2325 		}
2326 		mac->key_len = maclen;
2327 	}
2328 	if ((r = sshbuf_get_u32(b, &comp->type)) != 0 ||
2329 	    (r = sshbuf_get_cstring(b, &comp->name, NULL)) != 0)
2330 		goto out;
2331 	if (sshbuf_len(b) != 0) {
2332 		r = SSH_ERR_INVALID_FORMAT;
2333 		goto out;
2334 	}
2335 	enc->key_len = keylen;
2336 	enc->iv_len = ivlen;
2337 	ssh->kex->newkeys[mode] = newkey;
2338 	newkey = NULL;
2339 	r = 0;
2340  out:
2341 	free(newkey);
2342 	sshbuf_free(b);
2343 	return r;
2344 }
2345 
2346 /* restore kex from blob for packet state de-serialization */
2347 static int
2348 kex_from_blob(struct sshbuf *m, struct kex **kexp)
2349 {
2350 	struct kex *kex;
2351 	int r;
2352 
2353 	if ((kex = kex_new()) == NULL)
2354 		return SSH_ERR_ALLOC_FAIL;
2355 	if ((r = sshbuf_get_string(m, &kex->session_id, &kex->session_id_len)) != 0 ||
2356 	    (r = sshbuf_get_u32(m, &kex->we_need)) != 0 ||
2357 	    (r = sshbuf_get_cstring(m, &kex->hostkey_alg, NULL)) != 0 ||
2358 	    (r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_type)) != 0 ||
2359 	    (r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_nid)) != 0 ||
2360 	    (r = sshbuf_get_u32(m, &kex->kex_type)) != 0 ||
2361 	    (r = sshbuf_get_stringb(m, kex->my)) != 0 ||
2362 	    (r = sshbuf_get_stringb(m, kex->peer)) != 0 ||
2363 	    (r = sshbuf_get_stringb(m, kex->client_version)) != 0 ||
2364 	    (r = sshbuf_get_stringb(m, kex->server_version)) != 0 ||
2365 	    (r = sshbuf_get_u32(m, &kex->flags)) != 0)
2366 		goto out;
2367 	kex->server = 1;
2368 	kex->done = 1;
2369 	r = 0;
2370  out:
2371 	if (r != 0 || kexp == NULL) {
2372 		kex_free(kex);
2373 		if (kexp != NULL)
2374 			*kexp = NULL;
2375 	} else {
2376 		kex_free(*kexp);
2377 		*kexp = kex;
2378 	}
2379 	return r;
2380 }
2381 
2382 /*
2383  * Restore packet state from content of blob 'm' (de-serialization).
2384  * Note that 'm' will be partially consumed on parsing or any other errors.
2385  */
2386 int
2387 ssh_packet_set_state(struct ssh *ssh, struct sshbuf *m)
2388 {
2389 	struct session_state *state = ssh->state;
2390 	const u_char *input, *output;
2391 	size_t ilen, olen;
2392 	int r;
2393 
2394 	if ((r = kex_from_blob(m, &ssh->kex)) != 0 ||
2395 	    (r = newkeys_from_blob(m, ssh, MODE_OUT)) != 0 ||
2396 	    (r = newkeys_from_blob(m, ssh, MODE_IN)) != 0 ||
2397 	    (r = sshbuf_get_u64(m, &state->rekey_limit)) != 0 ||
2398 	    (r = sshbuf_get_u32(m, &state->rekey_interval)) != 0 ||
2399 	    (r = sshbuf_get_u32(m, &state->p_send.seqnr)) != 0 ||
2400 	    (r = sshbuf_get_u64(m, &state->p_send.blocks)) != 0 ||
2401 	    (r = sshbuf_get_u32(m, &state->p_send.packets)) != 0 ||
2402 	    (r = sshbuf_get_u64(m, &state->p_send.bytes)) != 0 ||
2403 	    (r = sshbuf_get_u32(m, &state->p_read.seqnr)) != 0 ||
2404 	    (r = sshbuf_get_u64(m, &state->p_read.blocks)) != 0 ||
2405 	    (r = sshbuf_get_u32(m, &state->p_read.packets)) != 0 ||
2406 	    (r = sshbuf_get_u64(m, &state->p_read.bytes)) != 0)
2407 		return r;
2408 	/*
2409 	 * We set the time here so that in post-auth privsep slave we
2410 	 * count from the completion of the authentication.
2411 	 */
2412 	state->rekey_time = monotime();
2413 	/* XXX ssh_set_newkeys overrides p_read.packets? XXX */
2414 	if ((r = ssh_set_newkeys(ssh, MODE_IN)) != 0 ||
2415 	    (r = ssh_set_newkeys(ssh, MODE_OUT)) != 0)
2416 		return r;
2417 
2418 	if ((r = ssh_packet_set_postauth(ssh)) != 0)
2419 		return r;
2420 
2421 	sshbuf_reset(state->input);
2422 	sshbuf_reset(state->output);
2423 	if ((r = sshbuf_get_string_direct(m, &input, &ilen)) != 0 ||
2424 	    (r = sshbuf_get_string_direct(m, &output, &olen)) != 0 ||
2425 	    (r = sshbuf_put(state->input, input, ilen)) != 0 ||
2426 	    (r = sshbuf_put(state->output, output, olen)) != 0)
2427 		return r;
2428 
2429 	if (sshbuf_len(m))
2430 		return SSH_ERR_INVALID_FORMAT;
2431 	debug3("%s: done", __func__);
2432 	return 0;
2433 }
2434 
2435 /* NEW API */
2436 
2437 /* put data to the outgoing packet */
2438 
2439 int
2440 sshpkt_put(struct ssh *ssh, const void *v, size_t len)
2441 {
2442 	return sshbuf_put(ssh->state->outgoing_packet, v, len);
2443 }
2444 
2445 int
2446 sshpkt_putb(struct ssh *ssh, const struct sshbuf *b)
2447 {
2448 	return sshbuf_putb(ssh->state->outgoing_packet, b);
2449 }
2450 
2451 int
2452 sshpkt_put_u8(struct ssh *ssh, u_char val)
2453 {
2454 	return sshbuf_put_u8(ssh->state->outgoing_packet, val);
2455 }
2456 
2457 int
2458 sshpkt_put_u32(struct ssh *ssh, u_int32_t val)
2459 {
2460 	return sshbuf_put_u32(ssh->state->outgoing_packet, val);
2461 }
2462 
2463 int
2464 sshpkt_put_u64(struct ssh *ssh, u_int64_t val)
2465 {
2466 	return sshbuf_put_u64(ssh->state->outgoing_packet, val);
2467 }
2468 
2469 int
2470 sshpkt_put_string(struct ssh *ssh, const void *v, size_t len)
2471 {
2472 	return sshbuf_put_string(ssh->state->outgoing_packet, v, len);
2473 }
2474 
2475 int
2476 sshpkt_put_cstring(struct ssh *ssh, const void *v)
2477 {
2478 	return sshbuf_put_cstring(ssh->state->outgoing_packet, v);
2479 }
2480 
2481 int
2482 sshpkt_put_stringb(struct ssh *ssh, const struct sshbuf *v)
2483 {
2484 	return sshbuf_put_stringb(ssh->state->outgoing_packet, v);
2485 }
2486 
2487 int
2488 sshpkt_getb_froms(struct ssh *ssh, struct sshbuf **valp)
2489 {
2490 	return sshbuf_froms(ssh->state->incoming_packet, valp);
2491 }
2492 
2493 #ifdef WITH_OPENSSL
2494 #ifdef OPENSSL_HAS_ECC
2495 int
2496 sshpkt_put_ec(struct ssh *ssh, const EC_POINT *v, const EC_GROUP *g)
2497 {
2498 	return sshbuf_put_ec(ssh->state->outgoing_packet, v, g);
2499 }
2500 #endif /* OPENSSL_HAS_ECC */
2501 
2502 
2503 int
2504 sshpkt_put_bignum2(struct ssh *ssh, const BIGNUM *v)
2505 {
2506 	return sshbuf_put_bignum2(ssh->state->outgoing_packet, v);
2507 }
2508 #endif /* WITH_OPENSSL */
2509 
2510 /* fetch data from the incoming packet */
2511 
2512 int
2513 sshpkt_get(struct ssh *ssh, void *valp, size_t len)
2514 {
2515 	return sshbuf_get(ssh->state->incoming_packet, valp, len);
2516 }
2517 
2518 int
2519 sshpkt_get_u8(struct ssh *ssh, u_char *valp)
2520 {
2521 	return sshbuf_get_u8(ssh->state->incoming_packet, valp);
2522 }
2523 
2524 int
2525 sshpkt_get_u32(struct ssh *ssh, u_int32_t *valp)
2526 {
2527 	return sshbuf_get_u32(ssh->state->incoming_packet, valp);
2528 }
2529 
2530 int
2531 sshpkt_get_u64(struct ssh *ssh, u_int64_t *valp)
2532 {
2533 	return sshbuf_get_u64(ssh->state->incoming_packet, valp);
2534 }
2535 
2536 int
2537 sshpkt_get_string(struct ssh *ssh, u_char **valp, size_t *lenp)
2538 {
2539 	return sshbuf_get_string(ssh->state->incoming_packet, valp, lenp);
2540 }
2541 
2542 int
2543 sshpkt_get_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp)
2544 {
2545 	return sshbuf_get_string_direct(ssh->state->incoming_packet, valp, lenp);
2546 }
2547 
2548 int
2549 sshpkt_peek_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp)
2550 {
2551 	return sshbuf_peek_string_direct(ssh->state->incoming_packet, valp, lenp);
2552 }
2553 
2554 int
2555 sshpkt_get_cstring(struct ssh *ssh, char **valp, size_t *lenp)
2556 {
2557 	return sshbuf_get_cstring(ssh->state->incoming_packet, valp, lenp);
2558 }
2559 
2560 #ifdef WITH_OPENSSL
2561 #ifdef OPENSSL_HAS_ECC
2562 int
2563 sshpkt_get_ec(struct ssh *ssh, EC_POINT *v, const EC_GROUP *g)
2564 {
2565 	return sshbuf_get_ec(ssh->state->incoming_packet, v, g);
2566 }
2567 #endif /* OPENSSL_HAS_ECC */
2568 
2569 int
2570 sshpkt_get_bignum2(struct ssh *ssh, BIGNUM **valp)
2571 {
2572 	return sshbuf_get_bignum2(ssh->state->incoming_packet, valp);
2573 }
2574 #endif /* WITH_OPENSSL */
2575 
2576 int
2577 sshpkt_get_end(struct ssh *ssh)
2578 {
2579 	if (sshbuf_len(ssh->state->incoming_packet) > 0)
2580 		return SSH_ERR_UNEXPECTED_TRAILING_DATA;
2581 	return 0;
2582 }
2583 
2584 const u_char *
2585 sshpkt_ptr(struct ssh *ssh, size_t *lenp)
2586 {
2587 	if (lenp != NULL)
2588 		*lenp = sshbuf_len(ssh->state->incoming_packet);
2589 	return sshbuf_ptr(ssh->state->incoming_packet);
2590 }
2591 
2592 /* start a new packet */
2593 
2594 int
2595 sshpkt_start(struct ssh *ssh, u_char type)
2596 {
2597 	u_char buf[6]; /* u32 packet length, u8 pad len, u8 type */
2598 
2599 	DBG(debug("packet_start[%d]", type));
2600 	memset(buf, 0, sizeof(buf));
2601 	buf[sizeof(buf) - 1] = type;
2602 	sshbuf_reset(ssh->state->outgoing_packet);
2603 	return sshbuf_put(ssh->state->outgoing_packet, buf, sizeof(buf));
2604 }
2605 
2606 static int
2607 ssh_packet_send_mux(struct ssh *ssh)
2608 {
2609 	struct session_state *state = ssh->state;
2610 	u_char type, *cp;
2611 	size_t len;
2612 	int r;
2613 
2614 	if (ssh->kex)
2615 		return SSH_ERR_INTERNAL_ERROR;
2616 	len = sshbuf_len(state->outgoing_packet);
2617 	if (len < 6)
2618 		return SSH_ERR_INTERNAL_ERROR;
2619 	cp = sshbuf_mutable_ptr(state->outgoing_packet);
2620 	type = cp[5];
2621 	if (ssh_packet_log_type(type))
2622 		debug3("%s: type %u", __func__, type);
2623 	/* drop everything, but the connection protocol */
2624 	if (type >= SSH2_MSG_CONNECTION_MIN &&
2625 	    type <= SSH2_MSG_CONNECTION_MAX) {
2626 		POKE_U32(cp, len - 4);
2627 		if ((r = sshbuf_putb(state->output,
2628 		    state->outgoing_packet)) != 0)
2629 			return r;
2630 		/* sshbuf_dump(state->output, stderr); */
2631 	}
2632 	sshbuf_reset(state->outgoing_packet);
2633 	return 0;
2634 }
2635 
2636 /*
2637  * 9.2.  Ignored Data Message
2638  *
2639  *   byte      SSH_MSG_IGNORE
2640  *   string    data
2641  *
2642  * All implementations MUST understand (and ignore) this message at any
2643  * time (after receiving the protocol version). No implementation is
2644  * required to send them. This message can be used as an additional
2645  * protection measure against advanced traffic analysis techniques.
2646  */
2647 int
2648 sshpkt_msg_ignore(struct ssh *ssh, u_int nbytes)
2649 {
2650 	u_int32_t rnd = 0;
2651 	int r;
2652 	u_int i;
2653 
2654 	if ((r = sshpkt_start(ssh, SSH2_MSG_IGNORE)) != 0 ||
2655 	    (r = sshpkt_put_u32(ssh, nbytes)) != 0)
2656 		return r;
2657 	for (i = 0; i < nbytes; i++) {
2658 		if (i % 4 == 0)
2659 			rnd = arc4random();
2660 		if ((r = sshpkt_put_u8(ssh, (u_char)rnd & 0xff)) != 0)
2661 			return r;
2662 		rnd >>= 8;
2663 	}
2664 	return 0;
2665 }
2666 
2667 /* send it */
2668 
2669 int
2670 sshpkt_send(struct ssh *ssh)
2671 {
2672 	if (ssh->state && ssh->state->mux)
2673 		return ssh_packet_send_mux(ssh);
2674 	return ssh_packet_send2(ssh);
2675 }
2676 
2677 int
2678 sshpkt_disconnect(struct ssh *ssh, const char *fmt,...)
2679 {
2680 	char buf[1024];
2681 	va_list args;
2682 	int r;
2683 
2684 	va_start(args, fmt);
2685 	vsnprintf(buf, sizeof(buf), fmt, args);
2686 	va_end(args);
2687 
2688 	if ((r = sshpkt_start(ssh, SSH2_MSG_DISCONNECT)) != 0 ||
2689 	    (r = sshpkt_put_u32(ssh, SSH2_DISCONNECT_PROTOCOL_ERROR)) != 0 ||
2690 	    (r = sshpkt_put_cstring(ssh, buf)) != 0 ||
2691 	    (r = sshpkt_put_cstring(ssh, "")) != 0 ||
2692 	    (r = sshpkt_send(ssh)) != 0)
2693 		return r;
2694 	return 0;
2695 }
2696 
2697 /* roundup current message to pad bytes */
2698 int
2699 sshpkt_add_padding(struct ssh *ssh, u_char pad)
2700 {
2701 	ssh->state->extra_pad = pad;
2702 	return 0;
2703 }
2704