xref: /openssh-portable/packet.c (revision e9552d60)
1 /* $OpenBSD: packet.c,v 1.283 2019/03/01 03:29:32 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 	const char *dir = mode == MODE_OUT ? "out" : "in";
845 
846 	debug2("set_newkeys: mode %d", mode);
847 
848 	if (mode == MODE_OUT) {
849 		ccp = &state->send_context;
850 		crypt_type = CIPHER_ENCRYPT;
851 		ps = &state->p_send;
852 		max_blocks = &state->max_blocks_out;
853 	} else {
854 		ccp = &state->receive_context;
855 		crypt_type = CIPHER_DECRYPT;
856 		ps = &state->p_read;
857 		max_blocks = &state->max_blocks_in;
858 	}
859 	if (state->newkeys[mode] != NULL) {
860 		debug("%s: rekeying %s, input %llu bytes %llu blocks, "
861 		   "output %llu bytes %llu blocks", __func__, dir,
862 		   (unsigned long long)state->p_read.bytes,
863 		   (unsigned long long)state->p_read.blocks,
864 		   (unsigned long long)state->p_send.bytes,
865 		   (unsigned long long)state->p_send.blocks);
866 		kex_free_newkeys(state->newkeys[mode]);
867 		state->newkeys[mode] = NULL;
868 	}
869 	/* note that both bytes and the seqnr are not reset */
870 	ps->packets = ps->blocks = 0;
871 	/* move newkeys from kex to state */
872 	if ((state->newkeys[mode] = ssh->kex->newkeys[mode]) == NULL)
873 		return SSH_ERR_INTERNAL_ERROR;
874 	ssh->kex->newkeys[mode] = NULL;
875 	enc  = &state->newkeys[mode]->enc;
876 	mac  = &state->newkeys[mode]->mac;
877 	comp = &state->newkeys[mode]->comp;
878 	if (cipher_authlen(enc->cipher) == 0) {
879 		if ((r = mac_init(mac)) != 0)
880 			return r;
881 	}
882 	mac->enabled = 1;
883 	DBG(debug("%s: cipher_init_context: %s", __func__, dir));
884 	cipher_free(*ccp);
885 	*ccp = NULL;
886 	if ((r = cipher_init(ccp, enc->cipher, enc->key, enc->key_len,
887 	    enc->iv, enc->iv_len, crypt_type)) != 0)
888 		return r;
889 	if (!state->cipher_warning_done &&
890 	    (wmsg = cipher_warning_message(*ccp)) != NULL) {
891 		error("Warning: %s", wmsg);
892 		state->cipher_warning_done = 1;
893 	}
894 	/* Deleting the keys does not gain extra security */
895 	/* explicit_bzero(enc->iv,  enc->block_size);
896 	   explicit_bzero(enc->key, enc->key_len);
897 	   explicit_bzero(mac->key, mac->key_len); */
898 	if ((comp->type == COMP_ZLIB ||
899 	    (comp->type == COMP_DELAYED &&
900 	     state->after_authentication)) && comp->enabled == 0) {
901 		if ((r = ssh_packet_init_compression(ssh)) < 0)
902 			return r;
903 		if (mode == MODE_OUT) {
904 			if ((r = start_compression_out(ssh, 6)) != 0)
905 				return r;
906 		} else {
907 			if ((r = start_compression_in(ssh)) != 0)
908 				return r;
909 		}
910 		comp->enabled = 1;
911 	}
912 	/*
913 	 * The 2^(blocksize*2) limit is too expensive for 3DES,
914 	 * so enforce a 1GB limit for small blocksizes.
915 	 * See RFC4344 section 3.2.
916 	 */
917 	if (enc->block_size >= 16)
918 		*max_blocks = (u_int64_t)1 << (enc->block_size*2);
919 	else
920 		*max_blocks = ((u_int64_t)1 << 30) / enc->block_size;
921 	if (state->rekey_limit)
922 		*max_blocks = MINIMUM(*max_blocks,
923 		    state->rekey_limit / enc->block_size);
924 	debug("rekey %s after %llu blocks", dir,
925 	    (unsigned long long)*max_blocks);
926 	return 0;
927 }
928 
929 #define MAX_PACKETS	(1U<<31)
930 static int
931 ssh_packet_need_rekeying(struct ssh *ssh, u_int outbound_packet_len)
932 {
933 	struct session_state *state = ssh->state;
934 	u_int32_t out_blocks;
935 
936 	/* XXX client can't cope with rekeying pre-auth */
937 	if (!state->after_authentication)
938 		return 0;
939 
940 	/* Haven't keyed yet or KEX in progress. */
941 	if (ssh_packet_is_rekeying(ssh))
942 		return 0;
943 
944 	/* Peer can't rekey */
945 	if (ssh->compat & SSH_BUG_NOREKEY)
946 		return 0;
947 
948 	/*
949 	 * Permit one packet in or out per rekey - this allows us to
950 	 * make progress when rekey limits are very small.
951 	 */
952 	if (state->p_send.packets == 0 && state->p_read.packets == 0)
953 		return 0;
954 
955 	/* Time-based rekeying */
956 	if (state->rekey_interval != 0 &&
957 	    (int64_t)state->rekey_time + state->rekey_interval <= monotime())
958 		return 1;
959 
960 	/*
961 	 * Always rekey when MAX_PACKETS sent in either direction
962 	 * As per RFC4344 section 3.1 we do this after 2^31 packets.
963 	 */
964 	if (state->p_send.packets > MAX_PACKETS ||
965 	    state->p_read.packets > MAX_PACKETS)
966 		return 1;
967 
968 	/* Rekey after (cipher-specific) maximum blocks */
969 	out_blocks = ROUNDUP(outbound_packet_len,
970 	    state->newkeys[MODE_OUT]->enc.block_size);
971 	return (state->max_blocks_out &&
972 	    (state->p_send.blocks + out_blocks > state->max_blocks_out)) ||
973 	    (state->max_blocks_in &&
974 	    (state->p_read.blocks > state->max_blocks_in));
975 }
976 
977 /*
978  * Delayed compression for SSH2 is enabled after authentication:
979  * This happens on the server side after a SSH2_MSG_USERAUTH_SUCCESS is sent,
980  * and on the client side after a SSH2_MSG_USERAUTH_SUCCESS is received.
981  */
982 static int
983 ssh_packet_enable_delayed_compress(struct ssh *ssh)
984 {
985 	struct session_state *state = ssh->state;
986 	struct sshcomp *comp = NULL;
987 	int r, mode;
988 
989 	/*
990 	 * Remember that we are past the authentication step, so rekeying
991 	 * with COMP_DELAYED will turn on compression immediately.
992 	 */
993 	state->after_authentication = 1;
994 	for (mode = 0; mode < MODE_MAX; mode++) {
995 		/* protocol error: USERAUTH_SUCCESS received before NEWKEYS */
996 		if (state->newkeys[mode] == NULL)
997 			continue;
998 		comp = &state->newkeys[mode]->comp;
999 		if (comp && !comp->enabled && comp->type == COMP_DELAYED) {
1000 			if ((r = ssh_packet_init_compression(ssh)) != 0)
1001 				return r;
1002 			if (mode == MODE_OUT) {
1003 				if ((r = start_compression_out(ssh, 6)) != 0)
1004 					return r;
1005 			} else {
1006 				if ((r = start_compression_in(ssh)) != 0)
1007 					return r;
1008 			}
1009 			comp->enabled = 1;
1010 		}
1011 	}
1012 	return 0;
1013 }
1014 
1015 /* Used to mute debug logging for noisy packet types */
1016 int
1017 ssh_packet_log_type(u_char type)
1018 {
1019 	switch (type) {
1020 	case SSH2_MSG_CHANNEL_DATA:
1021 	case SSH2_MSG_CHANNEL_EXTENDED_DATA:
1022 	case SSH2_MSG_CHANNEL_WINDOW_ADJUST:
1023 		return 0;
1024 	default:
1025 		return 1;
1026 	}
1027 }
1028 
1029 /*
1030  * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue)
1031  */
1032 int
1033 ssh_packet_send2_wrapped(struct ssh *ssh)
1034 {
1035 	struct session_state *state = ssh->state;
1036 	u_char type, *cp, macbuf[SSH_DIGEST_MAX_LENGTH];
1037 	u_char tmp, padlen, pad = 0;
1038 	u_int authlen = 0, aadlen = 0;
1039 	u_int len;
1040 	struct sshenc *enc   = NULL;
1041 	struct sshmac *mac   = NULL;
1042 	struct sshcomp *comp = NULL;
1043 	int r, block_size;
1044 
1045 	if (state->newkeys[MODE_OUT] != NULL) {
1046 		enc  = &state->newkeys[MODE_OUT]->enc;
1047 		mac  = &state->newkeys[MODE_OUT]->mac;
1048 		comp = &state->newkeys[MODE_OUT]->comp;
1049 		/* disable mac for authenticated encryption */
1050 		if ((authlen = cipher_authlen(enc->cipher)) != 0)
1051 			mac = NULL;
1052 	}
1053 	block_size = enc ? enc->block_size : 8;
1054 	aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0;
1055 
1056 	type = (sshbuf_ptr(state->outgoing_packet))[5];
1057 	if (ssh_packet_log_type(type))
1058 		debug3("send packet: type %u", type);
1059 #ifdef PACKET_DEBUG
1060 	fprintf(stderr, "plain:     ");
1061 	sshbuf_dump(state->outgoing_packet, stderr);
1062 #endif
1063 
1064 	if (comp && comp->enabled) {
1065 		len = sshbuf_len(state->outgoing_packet);
1066 		/* skip header, compress only payload */
1067 		if ((r = sshbuf_consume(state->outgoing_packet, 5)) != 0)
1068 			goto out;
1069 		sshbuf_reset(state->compression_buffer);
1070 		if ((r = compress_buffer(ssh, state->outgoing_packet,
1071 		    state->compression_buffer)) != 0)
1072 			goto out;
1073 		sshbuf_reset(state->outgoing_packet);
1074 		if ((r = sshbuf_put(state->outgoing_packet,
1075 		    "\0\0\0\0\0", 5)) != 0 ||
1076 		    (r = sshbuf_putb(state->outgoing_packet,
1077 		    state->compression_buffer)) != 0)
1078 			goto out;
1079 		DBG(debug("compression: raw %d compressed %zd", len,
1080 		    sshbuf_len(state->outgoing_packet)));
1081 	}
1082 
1083 	/* sizeof (packet_len + pad_len + payload) */
1084 	len = sshbuf_len(state->outgoing_packet);
1085 
1086 	/*
1087 	 * calc size of padding, alloc space, get random data,
1088 	 * minimum padding is 4 bytes
1089 	 */
1090 	len -= aadlen; /* packet length is not encrypted for EtM modes */
1091 	padlen = block_size - (len % block_size);
1092 	if (padlen < 4)
1093 		padlen += block_size;
1094 	if (state->extra_pad) {
1095 		tmp = state->extra_pad;
1096 		state->extra_pad =
1097 		    ROUNDUP(state->extra_pad, block_size);
1098 		/* check if roundup overflowed */
1099 		if (state->extra_pad < tmp)
1100 			return SSH_ERR_INVALID_ARGUMENT;
1101 		tmp = (len + padlen) % state->extra_pad;
1102 		/* Check whether pad calculation below will underflow */
1103 		if (tmp > state->extra_pad)
1104 			return SSH_ERR_INVALID_ARGUMENT;
1105 		pad = state->extra_pad - tmp;
1106 		DBG(debug3("%s: adding %d (len %d padlen %d extra_pad %d)",
1107 		    __func__, pad, len, padlen, state->extra_pad));
1108 		tmp = padlen;
1109 		padlen += pad;
1110 		/* Check whether padlen calculation overflowed */
1111 		if (padlen < tmp)
1112 			return SSH_ERR_INVALID_ARGUMENT; /* overflow */
1113 		state->extra_pad = 0;
1114 	}
1115 	if ((r = sshbuf_reserve(state->outgoing_packet, padlen, &cp)) != 0)
1116 		goto out;
1117 	if (enc && !cipher_ctx_is_plaintext(state->send_context)) {
1118 		/* random padding */
1119 		arc4random_buf(cp, padlen);
1120 	} else {
1121 		/* clear padding */
1122 		explicit_bzero(cp, padlen);
1123 	}
1124 	/* sizeof (packet_len + pad_len + payload + padding) */
1125 	len = sshbuf_len(state->outgoing_packet);
1126 	cp = sshbuf_mutable_ptr(state->outgoing_packet);
1127 	if (cp == NULL) {
1128 		r = SSH_ERR_INTERNAL_ERROR;
1129 		goto out;
1130 	}
1131 	/* packet_length includes payload, padding and padding length field */
1132 	POKE_U32(cp, len - 4);
1133 	cp[4] = padlen;
1134 	DBG(debug("send: len %d (includes padlen %d, aadlen %d)",
1135 	    len, padlen, aadlen));
1136 
1137 	/* compute MAC over seqnr and packet(length fields, payload, padding) */
1138 	if (mac && mac->enabled && !mac->etm) {
1139 		if ((r = mac_compute(mac, state->p_send.seqnr,
1140 		    sshbuf_ptr(state->outgoing_packet), len,
1141 		    macbuf, sizeof(macbuf))) != 0)
1142 			goto out;
1143 		DBG(debug("done calc MAC out #%d", state->p_send.seqnr));
1144 	}
1145 	/* encrypt packet and append to output buffer. */
1146 	if ((r = sshbuf_reserve(state->output,
1147 	    sshbuf_len(state->outgoing_packet) + authlen, &cp)) != 0)
1148 		goto out;
1149 	if ((r = cipher_crypt(state->send_context, state->p_send.seqnr, cp,
1150 	    sshbuf_ptr(state->outgoing_packet),
1151 	    len - aadlen, aadlen, authlen)) != 0)
1152 		goto out;
1153 	/* append unencrypted MAC */
1154 	if (mac && mac->enabled) {
1155 		if (mac->etm) {
1156 			/* EtM: compute mac over aadlen + cipher text */
1157 			if ((r = mac_compute(mac, state->p_send.seqnr,
1158 			    cp, len, macbuf, sizeof(macbuf))) != 0)
1159 				goto out;
1160 			DBG(debug("done calc MAC(EtM) out #%d",
1161 			    state->p_send.seqnr));
1162 		}
1163 		if ((r = sshbuf_put(state->output, macbuf, mac->mac_len)) != 0)
1164 			goto out;
1165 	}
1166 #ifdef PACKET_DEBUG
1167 	fprintf(stderr, "encrypted: ");
1168 	sshbuf_dump(state->output, stderr);
1169 #endif
1170 	/* increment sequence number for outgoing packets */
1171 	if (++state->p_send.seqnr == 0)
1172 		logit("outgoing seqnr wraps around");
1173 	if (++state->p_send.packets == 0)
1174 		if (!(ssh->compat & SSH_BUG_NOREKEY))
1175 			return SSH_ERR_NEED_REKEY;
1176 	state->p_send.blocks += len / block_size;
1177 	state->p_send.bytes += len;
1178 	sshbuf_reset(state->outgoing_packet);
1179 
1180 	if (type == SSH2_MSG_NEWKEYS)
1181 		r = ssh_set_newkeys(ssh, MODE_OUT);
1182 	else if (type == SSH2_MSG_USERAUTH_SUCCESS && state->server_side)
1183 		r = ssh_packet_enable_delayed_compress(ssh);
1184 	else
1185 		r = 0;
1186  out:
1187 	return r;
1188 }
1189 
1190 /* returns non-zero if the specified packet type is usec by KEX */
1191 static int
1192 ssh_packet_type_is_kex(u_char type)
1193 {
1194 	return
1195 	    type >= SSH2_MSG_TRANSPORT_MIN &&
1196 	    type <= SSH2_MSG_TRANSPORT_MAX &&
1197 	    type != SSH2_MSG_SERVICE_REQUEST &&
1198 	    type != SSH2_MSG_SERVICE_ACCEPT &&
1199 	    type != SSH2_MSG_EXT_INFO;
1200 }
1201 
1202 int
1203 ssh_packet_send2(struct ssh *ssh)
1204 {
1205 	struct session_state *state = ssh->state;
1206 	struct packet *p;
1207 	u_char type;
1208 	int r, need_rekey;
1209 
1210 	if (sshbuf_len(state->outgoing_packet) < 6)
1211 		return SSH_ERR_INTERNAL_ERROR;
1212 	type = sshbuf_ptr(state->outgoing_packet)[5];
1213 	need_rekey = !ssh_packet_type_is_kex(type) &&
1214 	    ssh_packet_need_rekeying(ssh, sshbuf_len(state->outgoing_packet));
1215 
1216 	/*
1217 	 * During rekeying we can only send key exchange messages.
1218 	 * Queue everything else.
1219 	 */
1220 	if ((need_rekey || state->rekeying) && !ssh_packet_type_is_kex(type)) {
1221 		if (need_rekey)
1222 			debug3("%s: rekex triggered", __func__);
1223 		debug("enqueue packet: %u", type);
1224 		p = calloc(1, sizeof(*p));
1225 		if (p == NULL)
1226 			return SSH_ERR_ALLOC_FAIL;
1227 		p->type = type;
1228 		p->payload = state->outgoing_packet;
1229 		TAILQ_INSERT_TAIL(&state->outgoing, p, next);
1230 		state->outgoing_packet = sshbuf_new();
1231 		if (state->outgoing_packet == NULL)
1232 			return SSH_ERR_ALLOC_FAIL;
1233 		if (need_rekey) {
1234 			/*
1235 			 * This packet triggered a rekey, so send the
1236 			 * KEXINIT now.
1237 			 * NB. reenters this function via kex_start_rekex().
1238 			 */
1239 			return kex_start_rekex(ssh);
1240 		}
1241 		return 0;
1242 	}
1243 
1244 	/* rekeying starts with sending KEXINIT */
1245 	if (type == SSH2_MSG_KEXINIT)
1246 		state->rekeying = 1;
1247 
1248 	if ((r = ssh_packet_send2_wrapped(ssh)) != 0)
1249 		return r;
1250 
1251 	/* after a NEWKEYS message we can send the complete queue */
1252 	if (type == SSH2_MSG_NEWKEYS) {
1253 		state->rekeying = 0;
1254 		state->rekey_time = monotime();
1255 		while ((p = TAILQ_FIRST(&state->outgoing))) {
1256 			type = p->type;
1257 			/*
1258 			 * If this packet triggers a rekex, then skip the
1259 			 * remaining packets in the queue for now.
1260 			 * NB. re-enters this function via kex_start_rekex.
1261 			 */
1262 			if (ssh_packet_need_rekeying(ssh,
1263 			    sshbuf_len(p->payload))) {
1264 				debug3("%s: queued packet triggered rekex",
1265 				    __func__);
1266 				return kex_start_rekex(ssh);
1267 			}
1268 			debug("dequeue packet: %u", type);
1269 			sshbuf_free(state->outgoing_packet);
1270 			state->outgoing_packet = p->payload;
1271 			TAILQ_REMOVE(&state->outgoing, p, next);
1272 			memset(p, 0, sizeof(*p));
1273 			free(p);
1274 			if ((r = ssh_packet_send2_wrapped(ssh)) != 0)
1275 				return r;
1276 		}
1277 	}
1278 	return 0;
1279 }
1280 
1281 /*
1282  * Waits until a packet has been received, and returns its type.  Note that
1283  * no other data is processed until this returns, so this function should not
1284  * be used during the interactive session.
1285  */
1286 
1287 int
1288 ssh_packet_read_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
1289 {
1290 	struct session_state *state = ssh->state;
1291 	int len, r, ms_remain;
1292 	fd_set *setp;
1293 	char buf[8192];
1294 	struct timeval timeout, start, *timeoutp = NULL;
1295 
1296 	DBG(debug("packet_read()"));
1297 
1298 	setp = calloc(howmany(state->connection_in + 1,
1299 	    NFDBITS), sizeof(fd_mask));
1300 	if (setp == NULL)
1301 		return SSH_ERR_ALLOC_FAIL;
1302 
1303 	/*
1304 	 * Since we are blocking, ensure that all written packets have
1305 	 * been sent.
1306 	 */
1307 	if ((r = ssh_packet_write_wait(ssh)) != 0)
1308 		goto out;
1309 
1310 	/* Stay in the loop until we have received a complete packet. */
1311 	for (;;) {
1312 		/* Try to read a packet from the buffer. */
1313 		r = ssh_packet_read_poll_seqnr(ssh, typep, seqnr_p);
1314 		if (r != 0)
1315 			break;
1316 		/* If we got a packet, return it. */
1317 		if (*typep != SSH_MSG_NONE)
1318 			break;
1319 		/*
1320 		 * Otherwise, wait for some data to arrive, add it to the
1321 		 * buffer, and try again.
1322 		 */
1323 		memset(setp, 0, howmany(state->connection_in + 1,
1324 		    NFDBITS) * sizeof(fd_mask));
1325 		FD_SET(state->connection_in, setp);
1326 
1327 		if (state->packet_timeout_ms > 0) {
1328 			ms_remain = state->packet_timeout_ms;
1329 			timeoutp = &timeout;
1330 		}
1331 		/* Wait for some data to arrive. */
1332 		for (;;) {
1333 			if (state->packet_timeout_ms != -1) {
1334 				ms_to_timeval(&timeout, ms_remain);
1335 				monotime_tv(&start);
1336 			}
1337 			if ((r = select(state->connection_in + 1, setp,
1338 			    NULL, NULL, timeoutp)) >= 0)
1339 				break;
1340 			if (errno != EAGAIN && errno != EINTR &&
1341 			    errno != EWOULDBLOCK) {
1342 				r = SSH_ERR_SYSTEM_ERROR;
1343 				goto out;
1344 			}
1345 			if (state->packet_timeout_ms == -1)
1346 				continue;
1347 			ms_subtract_diff(&start, &ms_remain);
1348 			if (ms_remain <= 0) {
1349 				r = 0;
1350 				break;
1351 			}
1352 		}
1353 		if (r == 0) {
1354 			r = SSH_ERR_CONN_TIMEOUT;
1355 			goto out;
1356 		}
1357 		/* Read data from the socket. */
1358 		len = read(state->connection_in, buf, sizeof(buf));
1359 		if (len == 0) {
1360 			r = SSH_ERR_CONN_CLOSED;
1361 			goto out;
1362 		}
1363 		if (len < 0) {
1364 			r = SSH_ERR_SYSTEM_ERROR;
1365 			goto out;
1366 		}
1367 
1368 		/* Append it to the buffer. */
1369 		if ((r = ssh_packet_process_incoming(ssh, buf, len)) != 0)
1370 			goto out;
1371 	}
1372  out:
1373 	free(setp);
1374 	return r;
1375 }
1376 
1377 int
1378 ssh_packet_read(struct ssh *ssh)
1379 {
1380 	u_char type;
1381 	int r;
1382 
1383 	if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0)
1384 		fatal("%s: %s", __func__, ssh_err(r));
1385 	return type;
1386 }
1387 
1388 /*
1389  * Waits until a packet has been received, verifies that its type matches
1390  * that given, and gives a fatal error and exits if there is a mismatch.
1391  */
1392 
1393 int
1394 ssh_packet_read_expect(struct ssh *ssh, u_int expected_type)
1395 {
1396 	int r;
1397 	u_char type;
1398 
1399 	if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0)
1400 		return r;
1401 	if (type != expected_type) {
1402 		if ((r = sshpkt_disconnect(ssh,
1403 		    "Protocol error: expected packet type %d, got %d",
1404 		    expected_type, type)) != 0)
1405 			return r;
1406 		return SSH_ERR_PROTOCOL_ERROR;
1407 	}
1408 	return 0;
1409 }
1410 
1411 static int
1412 ssh_packet_read_poll2_mux(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
1413 {
1414 	struct session_state *state = ssh->state;
1415 	const u_char *cp;
1416 	size_t need;
1417 	int r;
1418 
1419 	if (ssh->kex)
1420 		return SSH_ERR_INTERNAL_ERROR;
1421 	*typep = SSH_MSG_NONE;
1422 	cp = sshbuf_ptr(state->input);
1423 	if (state->packlen == 0) {
1424 		if (sshbuf_len(state->input) < 4 + 1)
1425 			return 0; /* packet is incomplete */
1426 		state->packlen = PEEK_U32(cp);
1427 		if (state->packlen < 4 + 1 ||
1428 		    state->packlen > PACKET_MAX_SIZE)
1429 			return SSH_ERR_MESSAGE_INCOMPLETE;
1430 	}
1431 	need = state->packlen + 4;
1432 	if (sshbuf_len(state->input) < need)
1433 		return 0; /* packet is incomplete */
1434 	sshbuf_reset(state->incoming_packet);
1435 	if ((r = sshbuf_put(state->incoming_packet, cp + 4,
1436 	    state->packlen)) != 0 ||
1437 	    (r = sshbuf_consume(state->input, need)) != 0 ||
1438 	    (r = sshbuf_get_u8(state->incoming_packet, NULL)) != 0 ||
1439 	    (r = sshbuf_get_u8(state->incoming_packet, typep)) != 0)
1440 		return r;
1441 	if (ssh_packet_log_type(*typep))
1442 		debug3("%s: type %u", __func__, *typep);
1443 	/* sshbuf_dump(state->incoming_packet, stderr); */
1444 	/* reset for next packet */
1445 	state->packlen = 0;
1446 	return r;
1447 }
1448 
1449 int
1450 ssh_packet_read_poll2(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
1451 {
1452 	struct session_state *state = ssh->state;
1453 	u_int padlen, need;
1454 	u_char *cp;
1455 	u_int maclen, aadlen = 0, authlen = 0, block_size;
1456 	struct sshenc *enc   = NULL;
1457 	struct sshmac *mac   = NULL;
1458 	struct sshcomp *comp = NULL;
1459 	int r;
1460 
1461 	if (state->mux)
1462 		return ssh_packet_read_poll2_mux(ssh, typep, seqnr_p);
1463 
1464 	*typep = SSH_MSG_NONE;
1465 
1466 	if (state->packet_discard)
1467 		return 0;
1468 
1469 	if (state->newkeys[MODE_IN] != NULL) {
1470 		enc  = &state->newkeys[MODE_IN]->enc;
1471 		mac  = &state->newkeys[MODE_IN]->mac;
1472 		comp = &state->newkeys[MODE_IN]->comp;
1473 		/* disable mac for authenticated encryption */
1474 		if ((authlen = cipher_authlen(enc->cipher)) != 0)
1475 			mac = NULL;
1476 	}
1477 	maclen = mac && mac->enabled ? mac->mac_len : 0;
1478 	block_size = enc ? enc->block_size : 8;
1479 	aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0;
1480 
1481 	if (aadlen && state->packlen == 0) {
1482 		if (cipher_get_length(state->receive_context,
1483 		    &state->packlen, state->p_read.seqnr,
1484 		    sshbuf_ptr(state->input), sshbuf_len(state->input)) != 0)
1485 			return 0;
1486 		if (state->packlen < 1 + 4 ||
1487 		    state->packlen > PACKET_MAX_SIZE) {
1488 #ifdef PACKET_DEBUG
1489 			sshbuf_dump(state->input, stderr);
1490 #endif
1491 			logit("Bad packet length %u.", state->packlen);
1492 			if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0)
1493 				return r;
1494 			return SSH_ERR_CONN_CORRUPT;
1495 		}
1496 		sshbuf_reset(state->incoming_packet);
1497 	} else if (state->packlen == 0) {
1498 		/*
1499 		 * check if input size is less than the cipher block size,
1500 		 * decrypt first block and extract length of incoming packet
1501 		 */
1502 		if (sshbuf_len(state->input) < block_size)
1503 			return 0;
1504 		sshbuf_reset(state->incoming_packet);
1505 		if ((r = sshbuf_reserve(state->incoming_packet, block_size,
1506 		    &cp)) != 0)
1507 			goto out;
1508 		if ((r = cipher_crypt(state->receive_context,
1509 		    state->p_send.seqnr, cp, sshbuf_ptr(state->input),
1510 		    block_size, 0, 0)) != 0)
1511 			goto out;
1512 		state->packlen = PEEK_U32(sshbuf_ptr(state->incoming_packet));
1513 		if (state->packlen < 1 + 4 ||
1514 		    state->packlen > PACKET_MAX_SIZE) {
1515 #ifdef PACKET_DEBUG
1516 			fprintf(stderr, "input: \n");
1517 			sshbuf_dump(state->input, stderr);
1518 			fprintf(stderr, "incoming_packet: \n");
1519 			sshbuf_dump(state->incoming_packet, stderr);
1520 #endif
1521 			logit("Bad packet length %u.", state->packlen);
1522 			return ssh_packet_start_discard(ssh, enc, mac, 0,
1523 			    PACKET_MAX_SIZE);
1524 		}
1525 		if ((r = sshbuf_consume(state->input, block_size)) != 0)
1526 			goto out;
1527 	}
1528 	DBG(debug("input: packet len %u", state->packlen+4));
1529 
1530 	if (aadlen) {
1531 		/* only the payload is encrypted */
1532 		need = state->packlen;
1533 	} else {
1534 		/*
1535 		 * the payload size and the payload are encrypted, but we
1536 		 * have a partial packet of block_size bytes
1537 		 */
1538 		need = 4 + state->packlen - block_size;
1539 	}
1540 	DBG(debug("partial packet: block %d, need %d, maclen %d, authlen %d,"
1541 	    " aadlen %d", block_size, need, maclen, authlen, aadlen));
1542 	if (need % block_size != 0) {
1543 		logit("padding error: need %d block %d mod %d",
1544 		    need, block_size, need % block_size);
1545 		return ssh_packet_start_discard(ssh, enc, mac, 0,
1546 		    PACKET_MAX_SIZE - block_size);
1547 	}
1548 	/*
1549 	 * check if the entire packet has been received and
1550 	 * decrypt into incoming_packet:
1551 	 * 'aadlen' bytes are unencrypted, but authenticated.
1552 	 * 'need' bytes are encrypted, followed by either
1553 	 * 'authlen' bytes of authentication tag or
1554 	 * 'maclen' bytes of message authentication code.
1555 	 */
1556 	if (sshbuf_len(state->input) < aadlen + need + authlen + maclen)
1557 		return 0; /* packet is incomplete */
1558 #ifdef PACKET_DEBUG
1559 	fprintf(stderr, "read_poll enc/full: ");
1560 	sshbuf_dump(state->input, stderr);
1561 #endif
1562 	/* EtM: check mac over encrypted input */
1563 	if (mac && mac->enabled && mac->etm) {
1564 		if ((r = mac_check(mac, state->p_read.seqnr,
1565 		    sshbuf_ptr(state->input), aadlen + need,
1566 		    sshbuf_ptr(state->input) + aadlen + need + authlen,
1567 		    maclen)) != 0) {
1568 			if (r == SSH_ERR_MAC_INVALID)
1569 				logit("Corrupted MAC on input.");
1570 			goto out;
1571 		}
1572 	}
1573 	if ((r = sshbuf_reserve(state->incoming_packet, aadlen + need,
1574 	    &cp)) != 0)
1575 		goto out;
1576 	if ((r = cipher_crypt(state->receive_context, state->p_read.seqnr, cp,
1577 	    sshbuf_ptr(state->input), need, aadlen, authlen)) != 0)
1578 		goto out;
1579 	if ((r = sshbuf_consume(state->input, aadlen + need + authlen)) != 0)
1580 		goto out;
1581 	if (mac && mac->enabled) {
1582 		/* Not EtM: check MAC over cleartext */
1583 		if (!mac->etm && (r = mac_check(mac, state->p_read.seqnr,
1584 		    sshbuf_ptr(state->incoming_packet),
1585 		    sshbuf_len(state->incoming_packet),
1586 		    sshbuf_ptr(state->input), maclen)) != 0) {
1587 			if (r != SSH_ERR_MAC_INVALID)
1588 				goto out;
1589 			logit("Corrupted MAC on input.");
1590 			if (need + block_size > PACKET_MAX_SIZE)
1591 				return SSH_ERR_INTERNAL_ERROR;
1592 			return ssh_packet_start_discard(ssh, enc, mac,
1593 			    sshbuf_len(state->incoming_packet),
1594 			    PACKET_MAX_SIZE - need - block_size);
1595 		}
1596 		/* Remove MAC from input buffer */
1597 		DBG(debug("MAC #%d ok", state->p_read.seqnr));
1598 		if ((r = sshbuf_consume(state->input, mac->mac_len)) != 0)
1599 			goto out;
1600 	}
1601 	if (seqnr_p != NULL)
1602 		*seqnr_p = state->p_read.seqnr;
1603 	if (++state->p_read.seqnr == 0)
1604 		logit("incoming seqnr wraps around");
1605 	if (++state->p_read.packets == 0)
1606 		if (!(ssh->compat & SSH_BUG_NOREKEY))
1607 			return SSH_ERR_NEED_REKEY;
1608 	state->p_read.blocks += (state->packlen + 4) / block_size;
1609 	state->p_read.bytes += state->packlen + 4;
1610 
1611 	/* get padlen */
1612 	padlen = sshbuf_ptr(state->incoming_packet)[4];
1613 	DBG(debug("input: padlen %d", padlen));
1614 	if (padlen < 4)	{
1615 		if ((r = sshpkt_disconnect(ssh,
1616 		    "Corrupted padlen %d on input.", padlen)) != 0 ||
1617 		    (r = ssh_packet_write_wait(ssh)) != 0)
1618 			return r;
1619 		return SSH_ERR_CONN_CORRUPT;
1620 	}
1621 
1622 	/* skip packet size + padlen, discard padding */
1623 	if ((r = sshbuf_consume(state->incoming_packet, 4 + 1)) != 0 ||
1624 	    ((r = sshbuf_consume_end(state->incoming_packet, padlen)) != 0))
1625 		goto out;
1626 
1627 	DBG(debug("input: len before de-compress %zd",
1628 	    sshbuf_len(state->incoming_packet)));
1629 	if (comp && comp->enabled) {
1630 		sshbuf_reset(state->compression_buffer);
1631 		if ((r = uncompress_buffer(ssh, state->incoming_packet,
1632 		    state->compression_buffer)) != 0)
1633 			goto out;
1634 		sshbuf_reset(state->incoming_packet);
1635 		if ((r = sshbuf_putb(state->incoming_packet,
1636 		    state->compression_buffer)) != 0)
1637 			goto out;
1638 		DBG(debug("input: len after de-compress %zd",
1639 		    sshbuf_len(state->incoming_packet)));
1640 	}
1641 	/*
1642 	 * get packet type, implies consume.
1643 	 * return length of payload (without type field)
1644 	 */
1645 	if ((r = sshbuf_get_u8(state->incoming_packet, typep)) != 0)
1646 		goto out;
1647 	if (ssh_packet_log_type(*typep))
1648 		debug3("receive packet: type %u", *typep);
1649 	if (*typep < SSH2_MSG_MIN || *typep >= SSH2_MSG_LOCAL_MIN) {
1650 		if ((r = sshpkt_disconnect(ssh,
1651 		    "Invalid ssh2 packet type: %d", *typep)) != 0 ||
1652 		    (r = ssh_packet_write_wait(ssh)) != 0)
1653 			return r;
1654 		return SSH_ERR_PROTOCOL_ERROR;
1655 	}
1656 	if (state->hook_in != NULL &&
1657 	    (r = state->hook_in(ssh, state->incoming_packet, typep,
1658 	    state->hook_in_ctx)) != 0)
1659 		return r;
1660 	if (*typep == SSH2_MSG_USERAUTH_SUCCESS && !state->server_side)
1661 		r = ssh_packet_enable_delayed_compress(ssh);
1662 	else
1663 		r = 0;
1664 #ifdef PACKET_DEBUG
1665 	fprintf(stderr, "read/plain[%d]:\r\n", *typep);
1666 	sshbuf_dump(state->incoming_packet, stderr);
1667 #endif
1668 	/* reset for next packet */
1669 	state->packlen = 0;
1670 
1671 	/* do we need to rekey? */
1672 	if (ssh_packet_need_rekeying(ssh, 0)) {
1673 		debug3("%s: rekex triggered", __func__);
1674 		if ((r = kex_start_rekex(ssh)) != 0)
1675 			return r;
1676 	}
1677  out:
1678 	return r;
1679 }
1680 
1681 int
1682 ssh_packet_read_poll_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
1683 {
1684 	struct session_state *state = ssh->state;
1685 	u_int reason, seqnr;
1686 	int r;
1687 	u_char *msg;
1688 
1689 	for (;;) {
1690 		msg = NULL;
1691 		r = ssh_packet_read_poll2(ssh, typep, seqnr_p);
1692 		if (r != 0)
1693 			return r;
1694 		if (*typep) {
1695 			state->keep_alive_timeouts = 0;
1696 			DBG(debug("received packet type %d", *typep));
1697 		}
1698 		switch (*typep) {
1699 		case SSH2_MSG_IGNORE:
1700 			debug3("Received SSH2_MSG_IGNORE");
1701 			break;
1702 		case SSH2_MSG_DEBUG:
1703 			if ((r = sshpkt_get_u8(ssh, NULL)) != 0 ||
1704 			    (r = sshpkt_get_string(ssh, &msg, NULL)) != 0 ||
1705 			    (r = sshpkt_get_string(ssh, NULL, NULL)) != 0) {
1706 				free(msg);
1707 				return r;
1708 			}
1709 			debug("Remote: %.900s", msg);
1710 			free(msg);
1711 			break;
1712 		case SSH2_MSG_DISCONNECT:
1713 			if ((r = sshpkt_get_u32(ssh, &reason)) != 0 ||
1714 			    (r = sshpkt_get_string(ssh, &msg, NULL)) != 0)
1715 				return r;
1716 			/* Ignore normal client exit notifications */
1717 			do_log2(ssh->state->server_side &&
1718 			    reason == SSH2_DISCONNECT_BY_APPLICATION ?
1719 			    SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_ERROR,
1720 			    "Received disconnect from %s port %d:"
1721 			    "%u: %.400s", ssh_remote_ipaddr(ssh),
1722 			    ssh_remote_port(ssh), reason, msg);
1723 			free(msg);
1724 			return SSH_ERR_DISCONNECTED;
1725 		case SSH2_MSG_UNIMPLEMENTED:
1726 			if ((r = sshpkt_get_u32(ssh, &seqnr)) != 0)
1727 				return r;
1728 			debug("Received SSH2_MSG_UNIMPLEMENTED for %u",
1729 			    seqnr);
1730 			break;
1731 		default:
1732 			return 0;
1733 		}
1734 	}
1735 }
1736 
1737 /*
1738  * Buffers the given amount of input characters.  This is intended to be used
1739  * together with packet_read_poll.
1740  */
1741 
1742 int
1743 ssh_packet_process_incoming(struct ssh *ssh, const char *buf, u_int len)
1744 {
1745 	struct session_state *state = ssh->state;
1746 	int r;
1747 
1748 	if (state->packet_discard) {
1749 		state->keep_alive_timeouts = 0; /* ?? */
1750 		if (len >= state->packet_discard) {
1751 			if ((r = ssh_packet_stop_discard(ssh)) != 0)
1752 				return r;
1753 		}
1754 		state->packet_discard -= len;
1755 		return 0;
1756 	}
1757 	if ((r = sshbuf_put(ssh->state->input, buf, len)) != 0)
1758 		return r;
1759 
1760 	return 0;
1761 }
1762 
1763 int
1764 ssh_packet_remaining(struct ssh *ssh)
1765 {
1766 	return sshbuf_len(ssh->state->incoming_packet);
1767 }
1768 
1769 /*
1770  * Sends a diagnostic message from the server to the client.  This message
1771  * can be sent at any time (but not while constructing another message). The
1772  * message is printed immediately, but only if the client is being executed
1773  * in verbose mode.  These messages are primarily intended to ease debugging
1774  * authentication problems.   The length of the formatted message must not
1775  * exceed 1024 bytes.  This will automatically call ssh_packet_write_wait.
1776  */
1777 void
1778 ssh_packet_send_debug(struct ssh *ssh, const char *fmt,...)
1779 {
1780 	char buf[1024];
1781 	va_list args;
1782 	int r;
1783 
1784 	if ((ssh->compat & SSH_BUG_DEBUG))
1785 		return;
1786 
1787 	va_start(args, fmt);
1788 	vsnprintf(buf, sizeof(buf), fmt, args);
1789 	va_end(args);
1790 
1791 	debug3("sending debug message: %s", buf);
1792 
1793 	if ((r = sshpkt_start(ssh, SSH2_MSG_DEBUG)) != 0 ||
1794 	    (r = sshpkt_put_u8(ssh, 0)) != 0 || /* always display */
1795 	    (r = sshpkt_put_cstring(ssh, buf)) != 0 ||
1796 	    (r = sshpkt_put_cstring(ssh, "")) != 0 ||
1797 	    (r = sshpkt_send(ssh)) != 0 ||
1798 	    (r = ssh_packet_write_wait(ssh)) != 0)
1799 		fatal("%s: %s", __func__, ssh_err(r));
1800 }
1801 
1802 void
1803 sshpkt_fmt_connection_id(struct ssh *ssh, char *s, size_t l)
1804 {
1805 	snprintf(s, l, "%.200s%s%s port %d",
1806 	    ssh->log_preamble ? ssh->log_preamble : "",
1807 	    ssh->log_preamble ? " " : "",
1808 	    ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
1809 }
1810 
1811 /*
1812  * Pretty-print connection-terminating errors and exit.
1813  */
1814 static void
1815 sshpkt_vfatal(struct ssh *ssh, int r, const char *fmt, va_list ap)
1816 {
1817 	char *tag = NULL, remote_id[512];
1818 
1819 	sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id));
1820 
1821 	switch (r) {
1822 	case SSH_ERR_CONN_CLOSED:
1823 		ssh_packet_clear_keys(ssh);
1824 		logdie("Connection closed by %s", remote_id);
1825 	case SSH_ERR_CONN_TIMEOUT:
1826 		ssh_packet_clear_keys(ssh);
1827 		logdie("Connection %s %s timed out",
1828 		    ssh->state->server_side ? "from" : "to", remote_id);
1829 	case SSH_ERR_DISCONNECTED:
1830 		ssh_packet_clear_keys(ssh);
1831 		logdie("Disconnected from %s", remote_id);
1832 	case SSH_ERR_SYSTEM_ERROR:
1833 		if (errno == ECONNRESET) {
1834 			ssh_packet_clear_keys(ssh);
1835 			logdie("Connection reset by %s", remote_id);
1836 		}
1837 		/* FALLTHROUGH */
1838 	case SSH_ERR_NO_CIPHER_ALG_MATCH:
1839 	case SSH_ERR_NO_MAC_ALG_MATCH:
1840 	case SSH_ERR_NO_COMPRESS_ALG_MATCH:
1841 	case SSH_ERR_NO_KEX_ALG_MATCH:
1842 	case SSH_ERR_NO_HOSTKEY_ALG_MATCH:
1843 		if (ssh && ssh->kex && ssh->kex->failed_choice) {
1844 			ssh_packet_clear_keys(ssh);
1845 			logdie("Unable to negotiate with %s: %s. "
1846 			    "Their offer: %s", remote_id, ssh_err(r),
1847 			    ssh->kex->failed_choice);
1848 		}
1849 		/* FALLTHROUGH */
1850 	default:
1851 		if (vasprintf(&tag, fmt, ap) == -1) {
1852 			ssh_packet_clear_keys(ssh);
1853 			logdie("%s: could not allocate failure message",
1854 			    __func__);
1855 		}
1856 		ssh_packet_clear_keys(ssh);
1857 		logdie("%s%sConnection %s %s: %s",
1858 		    tag != NULL ? tag : "", tag != NULL ? ": " : "",
1859 		    ssh->state->server_side ? "from" : "to",
1860 		    remote_id, ssh_err(r));
1861 	}
1862 }
1863 
1864 void
1865 sshpkt_fatal(struct ssh *ssh, int r, const char *fmt, ...)
1866 {
1867 	va_list ap;
1868 
1869 	va_start(ap, fmt);
1870 	sshpkt_vfatal(ssh, r, fmt, ap);
1871 	/* NOTREACHED */
1872 	va_end(ap);
1873 	logdie("%s: should have exited", __func__);
1874 }
1875 
1876 /*
1877  * Logs the error plus constructs and sends a disconnect packet, closes the
1878  * connection, and exits.  This function never returns. The error message
1879  * should not contain a newline.  The length of the formatted message must
1880  * not exceed 1024 bytes.
1881  */
1882 void
1883 ssh_packet_disconnect(struct ssh *ssh, const char *fmt,...)
1884 {
1885 	char buf[1024], remote_id[512];
1886 	va_list args;
1887 	static int disconnecting = 0;
1888 	int r;
1889 
1890 	if (disconnecting)	/* Guard against recursive invocations. */
1891 		fatal("packet_disconnect called recursively.");
1892 	disconnecting = 1;
1893 
1894 	/*
1895 	 * Format the message.  Note that the caller must make sure the
1896 	 * message is of limited size.
1897 	 */
1898 	sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id));
1899 	va_start(args, fmt);
1900 	vsnprintf(buf, sizeof(buf), fmt, args);
1901 	va_end(args);
1902 
1903 	/* Display the error locally */
1904 	logit("Disconnecting %s: %.100s", remote_id, buf);
1905 
1906 	/*
1907 	 * Send the disconnect message to the other side, and wait
1908 	 * for it to get sent.
1909 	 */
1910 	if ((r = sshpkt_disconnect(ssh, "%s", buf)) != 0)
1911 		sshpkt_fatal(ssh, r, "%s", __func__);
1912 
1913 	if ((r = ssh_packet_write_wait(ssh)) != 0)
1914 		sshpkt_fatal(ssh, r, "%s", __func__);
1915 
1916 	/* Close the connection. */
1917 	ssh_packet_close(ssh);
1918 	cleanup_exit(255);
1919 }
1920 
1921 /*
1922  * Checks if there is any buffered output, and tries to write some of
1923  * the output.
1924  */
1925 int
1926 ssh_packet_write_poll(struct ssh *ssh)
1927 {
1928 	struct session_state *state = ssh->state;
1929 	int len = sshbuf_len(state->output);
1930 	int r;
1931 
1932 	if (len > 0) {
1933 		len = write(state->connection_out,
1934 		    sshbuf_ptr(state->output), len);
1935 		if (len == -1) {
1936 			if (errno == EINTR || errno == EAGAIN ||
1937 			    errno == EWOULDBLOCK)
1938 				return 0;
1939 			return SSH_ERR_SYSTEM_ERROR;
1940 		}
1941 		if (len == 0)
1942 			return SSH_ERR_CONN_CLOSED;
1943 		if ((r = sshbuf_consume(state->output, len)) != 0)
1944 			return r;
1945 	}
1946 	return 0;
1947 }
1948 
1949 /*
1950  * Calls packet_write_poll repeatedly until all pending output data has been
1951  * written.
1952  */
1953 int
1954 ssh_packet_write_wait(struct ssh *ssh)
1955 {
1956 	fd_set *setp;
1957 	int ret, r, ms_remain = 0;
1958 	struct timeval start, timeout, *timeoutp = NULL;
1959 	struct session_state *state = ssh->state;
1960 
1961 	setp = calloc(howmany(state->connection_out + 1,
1962 	    NFDBITS), sizeof(fd_mask));
1963 	if (setp == NULL)
1964 		return SSH_ERR_ALLOC_FAIL;
1965 	if ((r = ssh_packet_write_poll(ssh)) != 0) {
1966 		free(setp);
1967 		return r;
1968 	}
1969 	while (ssh_packet_have_data_to_write(ssh)) {
1970 		memset(setp, 0, howmany(state->connection_out + 1,
1971 		    NFDBITS) * sizeof(fd_mask));
1972 		FD_SET(state->connection_out, setp);
1973 
1974 		if (state->packet_timeout_ms > 0) {
1975 			ms_remain = state->packet_timeout_ms;
1976 			timeoutp = &timeout;
1977 		}
1978 		for (;;) {
1979 			if (state->packet_timeout_ms != -1) {
1980 				ms_to_timeval(&timeout, ms_remain);
1981 				monotime_tv(&start);
1982 			}
1983 			if ((ret = select(state->connection_out + 1,
1984 			    NULL, setp, NULL, timeoutp)) >= 0)
1985 				break;
1986 			if (errno != EAGAIN && errno != EINTR &&
1987 			    errno != EWOULDBLOCK)
1988 				break;
1989 			if (state->packet_timeout_ms == -1)
1990 				continue;
1991 			ms_subtract_diff(&start, &ms_remain);
1992 			if (ms_remain <= 0) {
1993 				ret = 0;
1994 				break;
1995 			}
1996 		}
1997 		if (ret == 0) {
1998 			free(setp);
1999 			return SSH_ERR_CONN_TIMEOUT;
2000 		}
2001 		if ((r = ssh_packet_write_poll(ssh)) != 0) {
2002 			free(setp);
2003 			return r;
2004 		}
2005 	}
2006 	free(setp);
2007 	return 0;
2008 }
2009 
2010 /* Returns true if there is buffered data to write to the connection. */
2011 
2012 int
2013 ssh_packet_have_data_to_write(struct ssh *ssh)
2014 {
2015 	return sshbuf_len(ssh->state->output) != 0;
2016 }
2017 
2018 /* Returns true if there is not too much data to write to the connection. */
2019 
2020 int
2021 ssh_packet_not_very_much_data_to_write(struct ssh *ssh)
2022 {
2023 	if (ssh->state->interactive_mode)
2024 		return sshbuf_len(ssh->state->output) < 16384;
2025 	else
2026 		return sshbuf_len(ssh->state->output) < 128 * 1024;
2027 }
2028 
2029 void
2030 ssh_packet_set_tos(struct ssh *ssh, int tos)
2031 {
2032 #ifndef IP_TOS_IS_BROKEN
2033 	if (!ssh_packet_connection_is_on_socket(ssh) || tos == INT_MAX)
2034 		return;
2035 	switch (ssh_packet_connection_af(ssh)) {
2036 # ifdef IP_TOS
2037 	case AF_INET:
2038 		debug3("%s: set IP_TOS 0x%02x", __func__, tos);
2039 		if (setsockopt(ssh->state->connection_in,
2040 		    IPPROTO_IP, IP_TOS, &tos, sizeof(tos)) < 0)
2041 			error("setsockopt IP_TOS %d: %.100s:",
2042 			    tos, strerror(errno));
2043 		break;
2044 # endif /* IP_TOS */
2045 # ifdef IPV6_TCLASS
2046 	case AF_INET6:
2047 		debug3("%s: set IPV6_TCLASS 0x%02x", __func__, tos);
2048 		if (setsockopt(ssh->state->connection_in,
2049 		    IPPROTO_IPV6, IPV6_TCLASS, &tos, sizeof(tos)) < 0)
2050 			error("setsockopt IPV6_TCLASS %d: %.100s:",
2051 			    tos, strerror(errno));
2052 		break;
2053 # endif /* IPV6_TCLASS */
2054 	}
2055 #endif /* IP_TOS_IS_BROKEN */
2056 }
2057 
2058 /* Informs that the current session is interactive.  Sets IP flags for that. */
2059 
2060 void
2061 ssh_packet_set_interactive(struct ssh *ssh, int interactive, int qos_interactive, int qos_bulk)
2062 {
2063 	struct session_state *state = ssh->state;
2064 
2065 	if (state->set_interactive_called)
2066 		return;
2067 	state->set_interactive_called = 1;
2068 
2069 	/* Record that we are in interactive mode. */
2070 	state->interactive_mode = interactive;
2071 
2072 	/* Only set socket options if using a socket.  */
2073 	if (!ssh_packet_connection_is_on_socket(ssh))
2074 		return;
2075 	set_nodelay(state->connection_in);
2076 	ssh_packet_set_tos(ssh, interactive ? qos_interactive :
2077 	    qos_bulk);
2078 }
2079 
2080 /* Returns true if the current connection is interactive. */
2081 
2082 int
2083 ssh_packet_is_interactive(struct ssh *ssh)
2084 {
2085 	return ssh->state->interactive_mode;
2086 }
2087 
2088 int
2089 ssh_packet_set_maxsize(struct ssh *ssh, u_int s)
2090 {
2091 	struct session_state *state = ssh->state;
2092 
2093 	if (state->set_maxsize_called) {
2094 		logit("packet_set_maxsize: called twice: old %d new %d",
2095 		    state->max_packet_size, s);
2096 		return -1;
2097 	}
2098 	if (s < 4 * 1024 || s > 1024 * 1024) {
2099 		logit("packet_set_maxsize: bad size %d", s);
2100 		return -1;
2101 	}
2102 	state->set_maxsize_called = 1;
2103 	debug("packet_set_maxsize: setting to %d", s);
2104 	state->max_packet_size = s;
2105 	return s;
2106 }
2107 
2108 int
2109 ssh_packet_inc_alive_timeouts(struct ssh *ssh)
2110 {
2111 	return ++ssh->state->keep_alive_timeouts;
2112 }
2113 
2114 void
2115 ssh_packet_set_alive_timeouts(struct ssh *ssh, int ka)
2116 {
2117 	ssh->state->keep_alive_timeouts = ka;
2118 }
2119 
2120 u_int
2121 ssh_packet_get_maxsize(struct ssh *ssh)
2122 {
2123 	return ssh->state->max_packet_size;
2124 }
2125 
2126 void
2127 ssh_packet_set_rekey_limits(struct ssh *ssh, u_int64_t bytes, u_int32_t seconds)
2128 {
2129 	debug3("rekey after %llu bytes, %u seconds", (unsigned long long)bytes,
2130 	    (unsigned int)seconds);
2131 	ssh->state->rekey_limit = bytes;
2132 	ssh->state->rekey_interval = seconds;
2133 }
2134 
2135 time_t
2136 ssh_packet_get_rekey_timeout(struct ssh *ssh)
2137 {
2138 	time_t seconds;
2139 
2140 	seconds = ssh->state->rekey_time + ssh->state->rekey_interval -
2141 	    monotime();
2142 	return (seconds <= 0 ? 1 : seconds);
2143 }
2144 
2145 void
2146 ssh_packet_set_server(struct ssh *ssh)
2147 {
2148 	ssh->state->server_side = 1;
2149 	ssh->kex->server = 1; /* XXX unify? */
2150 }
2151 
2152 void
2153 ssh_packet_set_authenticated(struct ssh *ssh)
2154 {
2155 	ssh->state->after_authentication = 1;
2156 }
2157 
2158 void *
2159 ssh_packet_get_input(struct ssh *ssh)
2160 {
2161 	return (void *)ssh->state->input;
2162 }
2163 
2164 void *
2165 ssh_packet_get_output(struct ssh *ssh)
2166 {
2167 	return (void *)ssh->state->output;
2168 }
2169 
2170 /* Reset after_authentication and reset compression in post-auth privsep */
2171 static int
2172 ssh_packet_set_postauth(struct ssh *ssh)
2173 {
2174 	int r;
2175 
2176 	debug("%s: called", __func__);
2177 	/* This was set in net child, but is not visible in user child */
2178 	ssh->state->after_authentication = 1;
2179 	ssh->state->rekeying = 0;
2180 	if ((r = ssh_packet_enable_delayed_compress(ssh)) != 0)
2181 		return r;
2182 	return 0;
2183 }
2184 
2185 /* Packet state (de-)serialization for privsep */
2186 
2187 /* turn kex into a blob for packet state serialization */
2188 static int
2189 kex_to_blob(struct sshbuf *m, struct kex *kex)
2190 {
2191 	int r;
2192 
2193 	if ((r = sshbuf_put_string(m, kex->session_id,
2194 	    kex->session_id_len)) != 0 ||
2195 	    (r = sshbuf_put_u32(m, kex->we_need)) != 0 ||
2196 	    (r = sshbuf_put_cstring(m, kex->hostkey_alg)) != 0 ||
2197 	    (r = sshbuf_put_u32(m, kex->hostkey_type)) != 0 ||
2198 	    (r = sshbuf_put_u32(m, kex->hostkey_nid)) != 0 ||
2199 	    (r = sshbuf_put_u32(m, kex->kex_type)) != 0 ||
2200 	    (r = sshbuf_put_stringb(m, kex->my)) != 0 ||
2201 	    (r = sshbuf_put_stringb(m, kex->peer)) != 0 ||
2202 	    (r = sshbuf_put_stringb(m, kex->client_version)) != 0 ||
2203 	    (r = sshbuf_put_stringb(m, kex->server_version)) != 0 ||
2204 	    (r = sshbuf_put_u32(m, kex->flags)) != 0)
2205 		return r;
2206 	return 0;
2207 }
2208 
2209 /* turn key exchange results into a blob for packet state serialization */
2210 static int
2211 newkeys_to_blob(struct sshbuf *m, struct ssh *ssh, int mode)
2212 {
2213 	struct sshbuf *b;
2214 	struct sshcipher_ctx *cc;
2215 	struct sshcomp *comp;
2216 	struct sshenc *enc;
2217 	struct sshmac *mac;
2218 	struct newkeys *newkey;
2219 	int r;
2220 
2221 	if ((newkey = ssh->state->newkeys[mode]) == NULL)
2222 		return SSH_ERR_INTERNAL_ERROR;
2223 	enc = &newkey->enc;
2224 	mac = &newkey->mac;
2225 	comp = &newkey->comp;
2226 	cc = (mode == MODE_OUT) ? ssh->state->send_context :
2227 	    ssh->state->receive_context;
2228 	if ((r = cipher_get_keyiv(cc, enc->iv, enc->iv_len)) != 0)
2229 		return r;
2230 	if ((b = sshbuf_new()) == NULL)
2231 		return SSH_ERR_ALLOC_FAIL;
2232 	if ((r = sshbuf_put_cstring(b, enc->name)) != 0 ||
2233 	    (r = sshbuf_put_u32(b, enc->enabled)) != 0 ||
2234 	    (r = sshbuf_put_u32(b, enc->block_size)) != 0 ||
2235 	    (r = sshbuf_put_string(b, enc->key, enc->key_len)) != 0 ||
2236 	    (r = sshbuf_put_string(b, enc->iv, enc->iv_len)) != 0)
2237 		goto out;
2238 	if (cipher_authlen(enc->cipher) == 0) {
2239 		if ((r = sshbuf_put_cstring(b, mac->name)) != 0 ||
2240 		    (r = sshbuf_put_u32(b, mac->enabled)) != 0 ||
2241 		    (r = sshbuf_put_string(b, mac->key, mac->key_len)) != 0)
2242 			goto out;
2243 	}
2244 	if ((r = sshbuf_put_u32(b, comp->type)) != 0 ||
2245 	    (r = sshbuf_put_cstring(b, comp->name)) != 0)
2246 		goto out;
2247 	r = sshbuf_put_stringb(m, b);
2248  out:
2249 	sshbuf_free(b);
2250 	return r;
2251 }
2252 
2253 /* serialize packet state into a blob */
2254 int
2255 ssh_packet_get_state(struct ssh *ssh, struct sshbuf *m)
2256 {
2257 	struct session_state *state = ssh->state;
2258 	int r;
2259 
2260 	if ((r = kex_to_blob(m, ssh->kex)) != 0 ||
2261 	    (r = newkeys_to_blob(m, ssh, MODE_OUT)) != 0 ||
2262 	    (r = newkeys_to_blob(m, ssh, MODE_IN)) != 0 ||
2263 	    (r = sshbuf_put_u64(m, state->rekey_limit)) != 0 ||
2264 	    (r = sshbuf_put_u32(m, state->rekey_interval)) != 0 ||
2265 	    (r = sshbuf_put_u32(m, state->p_send.seqnr)) != 0 ||
2266 	    (r = sshbuf_put_u64(m, state->p_send.blocks)) != 0 ||
2267 	    (r = sshbuf_put_u32(m, state->p_send.packets)) != 0 ||
2268 	    (r = sshbuf_put_u64(m, state->p_send.bytes)) != 0 ||
2269 	    (r = sshbuf_put_u32(m, state->p_read.seqnr)) != 0 ||
2270 	    (r = sshbuf_put_u64(m, state->p_read.blocks)) != 0 ||
2271 	    (r = sshbuf_put_u32(m, state->p_read.packets)) != 0 ||
2272 	    (r = sshbuf_put_u64(m, state->p_read.bytes)) != 0 ||
2273 	    (r = sshbuf_put_stringb(m, state->input)) != 0 ||
2274 	    (r = sshbuf_put_stringb(m, state->output)) != 0)
2275 		return r;
2276 
2277 	return 0;
2278 }
2279 
2280 /* restore key exchange results from blob for packet state de-serialization */
2281 static int
2282 newkeys_from_blob(struct sshbuf *m, struct ssh *ssh, int mode)
2283 {
2284 	struct sshbuf *b = NULL;
2285 	struct sshcomp *comp;
2286 	struct sshenc *enc;
2287 	struct sshmac *mac;
2288 	struct newkeys *newkey = NULL;
2289 	size_t keylen, ivlen, maclen;
2290 	int r;
2291 
2292 	if ((newkey = calloc(1, sizeof(*newkey))) == NULL) {
2293 		r = SSH_ERR_ALLOC_FAIL;
2294 		goto out;
2295 	}
2296 	if ((r = sshbuf_froms(m, &b)) != 0)
2297 		goto out;
2298 #ifdef DEBUG_PK
2299 	sshbuf_dump(b, stderr);
2300 #endif
2301 	enc = &newkey->enc;
2302 	mac = &newkey->mac;
2303 	comp = &newkey->comp;
2304 
2305 	if ((r = sshbuf_get_cstring(b, &enc->name, NULL)) != 0 ||
2306 	    (r = sshbuf_get_u32(b, (u_int *)&enc->enabled)) != 0 ||
2307 	    (r = sshbuf_get_u32(b, &enc->block_size)) != 0 ||
2308 	    (r = sshbuf_get_string(b, &enc->key, &keylen)) != 0 ||
2309 	    (r = sshbuf_get_string(b, &enc->iv, &ivlen)) != 0)
2310 		goto out;
2311 	if ((enc->cipher = cipher_by_name(enc->name)) == NULL) {
2312 		r = SSH_ERR_INVALID_FORMAT;
2313 		goto out;
2314 	}
2315 	if (cipher_authlen(enc->cipher) == 0) {
2316 		if ((r = sshbuf_get_cstring(b, &mac->name, NULL)) != 0)
2317 			goto out;
2318 		if ((r = mac_setup(mac, mac->name)) != 0)
2319 			goto out;
2320 		if ((r = sshbuf_get_u32(b, (u_int *)&mac->enabled)) != 0 ||
2321 		    (r = sshbuf_get_string(b, &mac->key, &maclen)) != 0)
2322 			goto out;
2323 		if (maclen > mac->key_len) {
2324 			r = SSH_ERR_INVALID_FORMAT;
2325 			goto out;
2326 		}
2327 		mac->key_len = maclen;
2328 	}
2329 	if ((r = sshbuf_get_u32(b, &comp->type)) != 0 ||
2330 	    (r = sshbuf_get_cstring(b, &comp->name, NULL)) != 0)
2331 		goto out;
2332 	if (sshbuf_len(b) != 0) {
2333 		r = SSH_ERR_INVALID_FORMAT;
2334 		goto out;
2335 	}
2336 	enc->key_len = keylen;
2337 	enc->iv_len = ivlen;
2338 	ssh->kex->newkeys[mode] = newkey;
2339 	newkey = NULL;
2340 	r = 0;
2341  out:
2342 	free(newkey);
2343 	sshbuf_free(b);
2344 	return r;
2345 }
2346 
2347 /* restore kex from blob for packet state de-serialization */
2348 static int
2349 kex_from_blob(struct sshbuf *m, struct kex **kexp)
2350 {
2351 	struct kex *kex;
2352 	int r;
2353 
2354 	if ((kex = kex_new()) == NULL)
2355 		return SSH_ERR_ALLOC_FAIL;
2356 	if ((r = sshbuf_get_string(m, &kex->session_id, &kex->session_id_len)) != 0 ||
2357 	    (r = sshbuf_get_u32(m, &kex->we_need)) != 0 ||
2358 	    (r = sshbuf_get_cstring(m, &kex->hostkey_alg, NULL)) != 0 ||
2359 	    (r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_type)) != 0 ||
2360 	    (r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_nid)) != 0 ||
2361 	    (r = sshbuf_get_u32(m, &kex->kex_type)) != 0 ||
2362 	    (r = sshbuf_get_stringb(m, kex->my)) != 0 ||
2363 	    (r = sshbuf_get_stringb(m, kex->peer)) != 0 ||
2364 	    (r = sshbuf_get_stringb(m, kex->client_version)) != 0 ||
2365 	    (r = sshbuf_get_stringb(m, kex->server_version)) != 0 ||
2366 	    (r = sshbuf_get_u32(m, &kex->flags)) != 0)
2367 		goto out;
2368 	kex->server = 1;
2369 	kex->done = 1;
2370 	r = 0;
2371  out:
2372 	if (r != 0 || kexp == NULL) {
2373 		kex_free(kex);
2374 		if (kexp != NULL)
2375 			*kexp = NULL;
2376 	} else {
2377 		kex_free(*kexp);
2378 		*kexp = kex;
2379 	}
2380 	return r;
2381 }
2382 
2383 /*
2384  * Restore packet state from content of blob 'm' (de-serialization).
2385  * Note that 'm' will be partially consumed on parsing or any other errors.
2386  */
2387 int
2388 ssh_packet_set_state(struct ssh *ssh, struct sshbuf *m)
2389 {
2390 	struct session_state *state = ssh->state;
2391 	const u_char *input, *output;
2392 	size_t ilen, olen;
2393 	int r;
2394 
2395 	if ((r = kex_from_blob(m, &ssh->kex)) != 0 ||
2396 	    (r = newkeys_from_blob(m, ssh, MODE_OUT)) != 0 ||
2397 	    (r = newkeys_from_blob(m, ssh, MODE_IN)) != 0 ||
2398 	    (r = sshbuf_get_u64(m, &state->rekey_limit)) != 0 ||
2399 	    (r = sshbuf_get_u32(m, &state->rekey_interval)) != 0 ||
2400 	    (r = sshbuf_get_u32(m, &state->p_send.seqnr)) != 0 ||
2401 	    (r = sshbuf_get_u64(m, &state->p_send.blocks)) != 0 ||
2402 	    (r = sshbuf_get_u32(m, &state->p_send.packets)) != 0 ||
2403 	    (r = sshbuf_get_u64(m, &state->p_send.bytes)) != 0 ||
2404 	    (r = sshbuf_get_u32(m, &state->p_read.seqnr)) != 0 ||
2405 	    (r = sshbuf_get_u64(m, &state->p_read.blocks)) != 0 ||
2406 	    (r = sshbuf_get_u32(m, &state->p_read.packets)) != 0 ||
2407 	    (r = sshbuf_get_u64(m, &state->p_read.bytes)) != 0)
2408 		return r;
2409 	/*
2410 	 * We set the time here so that in post-auth privsep slave we
2411 	 * count from the completion of the authentication.
2412 	 */
2413 	state->rekey_time = monotime();
2414 	/* XXX ssh_set_newkeys overrides p_read.packets? XXX */
2415 	if ((r = ssh_set_newkeys(ssh, MODE_IN)) != 0 ||
2416 	    (r = ssh_set_newkeys(ssh, MODE_OUT)) != 0)
2417 		return r;
2418 
2419 	if ((r = ssh_packet_set_postauth(ssh)) != 0)
2420 		return r;
2421 
2422 	sshbuf_reset(state->input);
2423 	sshbuf_reset(state->output);
2424 	if ((r = sshbuf_get_string_direct(m, &input, &ilen)) != 0 ||
2425 	    (r = sshbuf_get_string_direct(m, &output, &olen)) != 0 ||
2426 	    (r = sshbuf_put(state->input, input, ilen)) != 0 ||
2427 	    (r = sshbuf_put(state->output, output, olen)) != 0)
2428 		return r;
2429 
2430 	if (sshbuf_len(m))
2431 		return SSH_ERR_INVALID_FORMAT;
2432 	debug3("%s: done", __func__);
2433 	return 0;
2434 }
2435 
2436 /* NEW API */
2437 
2438 /* put data to the outgoing packet */
2439 
2440 int
2441 sshpkt_put(struct ssh *ssh, const void *v, size_t len)
2442 {
2443 	return sshbuf_put(ssh->state->outgoing_packet, v, len);
2444 }
2445 
2446 int
2447 sshpkt_putb(struct ssh *ssh, const struct sshbuf *b)
2448 {
2449 	return sshbuf_putb(ssh->state->outgoing_packet, b);
2450 }
2451 
2452 int
2453 sshpkt_put_u8(struct ssh *ssh, u_char val)
2454 {
2455 	return sshbuf_put_u8(ssh->state->outgoing_packet, val);
2456 }
2457 
2458 int
2459 sshpkt_put_u32(struct ssh *ssh, u_int32_t val)
2460 {
2461 	return sshbuf_put_u32(ssh->state->outgoing_packet, val);
2462 }
2463 
2464 int
2465 sshpkt_put_u64(struct ssh *ssh, u_int64_t val)
2466 {
2467 	return sshbuf_put_u64(ssh->state->outgoing_packet, val);
2468 }
2469 
2470 int
2471 sshpkt_put_string(struct ssh *ssh, const void *v, size_t len)
2472 {
2473 	return sshbuf_put_string(ssh->state->outgoing_packet, v, len);
2474 }
2475 
2476 int
2477 sshpkt_put_cstring(struct ssh *ssh, const void *v)
2478 {
2479 	return sshbuf_put_cstring(ssh->state->outgoing_packet, v);
2480 }
2481 
2482 int
2483 sshpkt_put_stringb(struct ssh *ssh, const struct sshbuf *v)
2484 {
2485 	return sshbuf_put_stringb(ssh->state->outgoing_packet, v);
2486 }
2487 
2488 int
2489 sshpkt_getb_froms(struct ssh *ssh, struct sshbuf **valp)
2490 {
2491 	return sshbuf_froms(ssh->state->incoming_packet, valp);
2492 }
2493 
2494 #ifdef WITH_OPENSSL
2495 #ifdef OPENSSL_HAS_ECC
2496 int
2497 sshpkt_put_ec(struct ssh *ssh, const EC_POINT *v, const EC_GROUP *g)
2498 {
2499 	return sshbuf_put_ec(ssh->state->outgoing_packet, v, g);
2500 }
2501 #endif /* OPENSSL_HAS_ECC */
2502 
2503 
2504 int
2505 sshpkt_put_bignum2(struct ssh *ssh, const BIGNUM *v)
2506 {
2507 	return sshbuf_put_bignum2(ssh->state->outgoing_packet, v);
2508 }
2509 #endif /* WITH_OPENSSL */
2510 
2511 /* fetch data from the incoming packet */
2512 
2513 int
2514 sshpkt_get(struct ssh *ssh, void *valp, size_t len)
2515 {
2516 	return sshbuf_get(ssh->state->incoming_packet, valp, len);
2517 }
2518 
2519 int
2520 sshpkt_get_u8(struct ssh *ssh, u_char *valp)
2521 {
2522 	return sshbuf_get_u8(ssh->state->incoming_packet, valp);
2523 }
2524 
2525 int
2526 sshpkt_get_u32(struct ssh *ssh, u_int32_t *valp)
2527 {
2528 	return sshbuf_get_u32(ssh->state->incoming_packet, valp);
2529 }
2530 
2531 int
2532 sshpkt_get_u64(struct ssh *ssh, u_int64_t *valp)
2533 {
2534 	return sshbuf_get_u64(ssh->state->incoming_packet, valp);
2535 }
2536 
2537 int
2538 sshpkt_get_string(struct ssh *ssh, u_char **valp, size_t *lenp)
2539 {
2540 	return sshbuf_get_string(ssh->state->incoming_packet, valp, lenp);
2541 }
2542 
2543 int
2544 sshpkt_get_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp)
2545 {
2546 	return sshbuf_get_string_direct(ssh->state->incoming_packet, valp, lenp);
2547 }
2548 
2549 int
2550 sshpkt_peek_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp)
2551 {
2552 	return sshbuf_peek_string_direct(ssh->state->incoming_packet, valp, lenp);
2553 }
2554 
2555 int
2556 sshpkt_get_cstring(struct ssh *ssh, char **valp, size_t *lenp)
2557 {
2558 	return sshbuf_get_cstring(ssh->state->incoming_packet, valp, lenp);
2559 }
2560 
2561 #ifdef WITH_OPENSSL
2562 #ifdef OPENSSL_HAS_ECC
2563 int
2564 sshpkt_get_ec(struct ssh *ssh, EC_POINT *v, const EC_GROUP *g)
2565 {
2566 	return sshbuf_get_ec(ssh->state->incoming_packet, v, g);
2567 }
2568 #endif /* OPENSSL_HAS_ECC */
2569 
2570 int
2571 sshpkt_get_bignum2(struct ssh *ssh, BIGNUM **valp)
2572 {
2573 	return sshbuf_get_bignum2(ssh->state->incoming_packet, valp);
2574 }
2575 #endif /* WITH_OPENSSL */
2576 
2577 int
2578 sshpkt_get_end(struct ssh *ssh)
2579 {
2580 	if (sshbuf_len(ssh->state->incoming_packet) > 0)
2581 		return SSH_ERR_UNEXPECTED_TRAILING_DATA;
2582 	return 0;
2583 }
2584 
2585 const u_char *
2586 sshpkt_ptr(struct ssh *ssh, size_t *lenp)
2587 {
2588 	if (lenp != NULL)
2589 		*lenp = sshbuf_len(ssh->state->incoming_packet);
2590 	return sshbuf_ptr(ssh->state->incoming_packet);
2591 }
2592 
2593 /* start a new packet */
2594 
2595 int
2596 sshpkt_start(struct ssh *ssh, u_char type)
2597 {
2598 	u_char buf[6]; /* u32 packet length, u8 pad len, u8 type */
2599 
2600 	DBG(debug("packet_start[%d]", type));
2601 	memset(buf, 0, sizeof(buf));
2602 	buf[sizeof(buf) - 1] = type;
2603 	sshbuf_reset(ssh->state->outgoing_packet);
2604 	return sshbuf_put(ssh->state->outgoing_packet, buf, sizeof(buf));
2605 }
2606 
2607 static int
2608 ssh_packet_send_mux(struct ssh *ssh)
2609 {
2610 	struct session_state *state = ssh->state;
2611 	u_char type, *cp;
2612 	size_t len;
2613 	int r;
2614 
2615 	if (ssh->kex)
2616 		return SSH_ERR_INTERNAL_ERROR;
2617 	len = sshbuf_len(state->outgoing_packet);
2618 	if (len < 6)
2619 		return SSH_ERR_INTERNAL_ERROR;
2620 	cp = sshbuf_mutable_ptr(state->outgoing_packet);
2621 	type = cp[5];
2622 	if (ssh_packet_log_type(type))
2623 		debug3("%s: type %u", __func__, type);
2624 	/* drop everything, but the connection protocol */
2625 	if (type >= SSH2_MSG_CONNECTION_MIN &&
2626 	    type <= SSH2_MSG_CONNECTION_MAX) {
2627 		POKE_U32(cp, len - 4);
2628 		if ((r = sshbuf_putb(state->output,
2629 		    state->outgoing_packet)) != 0)
2630 			return r;
2631 		/* sshbuf_dump(state->output, stderr); */
2632 	}
2633 	sshbuf_reset(state->outgoing_packet);
2634 	return 0;
2635 }
2636 
2637 /*
2638  * 9.2.  Ignored Data Message
2639  *
2640  *   byte      SSH_MSG_IGNORE
2641  *   string    data
2642  *
2643  * All implementations MUST understand (and ignore) this message at any
2644  * time (after receiving the protocol version). No implementation is
2645  * required to send them. This message can be used as an additional
2646  * protection measure against advanced traffic analysis techniques.
2647  */
2648 int
2649 sshpkt_msg_ignore(struct ssh *ssh, u_int nbytes)
2650 {
2651 	u_int32_t rnd = 0;
2652 	int r;
2653 	u_int i;
2654 
2655 	if ((r = sshpkt_start(ssh, SSH2_MSG_IGNORE)) != 0 ||
2656 	    (r = sshpkt_put_u32(ssh, nbytes)) != 0)
2657 		return r;
2658 	for (i = 0; i < nbytes; i++) {
2659 		if (i % 4 == 0)
2660 			rnd = arc4random();
2661 		if ((r = sshpkt_put_u8(ssh, (u_char)rnd & 0xff)) != 0)
2662 			return r;
2663 		rnd >>= 8;
2664 	}
2665 	return 0;
2666 }
2667 
2668 /* send it */
2669 
2670 int
2671 sshpkt_send(struct ssh *ssh)
2672 {
2673 	if (ssh->state && ssh->state->mux)
2674 		return ssh_packet_send_mux(ssh);
2675 	return ssh_packet_send2(ssh);
2676 }
2677 
2678 int
2679 sshpkt_disconnect(struct ssh *ssh, const char *fmt,...)
2680 {
2681 	char buf[1024];
2682 	va_list args;
2683 	int r;
2684 
2685 	va_start(args, fmt);
2686 	vsnprintf(buf, sizeof(buf), fmt, args);
2687 	va_end(args);
2688 
2689 	if ((r = sshpkt_start(ssh, SSH2_MSG_DISCONNECT)) != 0 ||
2690 	    (r = sshpkt_put_u32(ssh, SSH2_DISCONNECT_PROTOCOL_ERROR)) != 0 ||
2691 	    (r = sshpkt_put_cstring(ssh, buf)) != 0 ||
2692 	    (r = sshpkt_put_cstring(ssh, "")) != 0 ||
2693 	    (r = sshpkt_send(ssh)) != 0)
2694 		return r;
2695 	return 0;
2696 }
2697 
2698 /* roundup current message to pad bytes */
2699 int
2700 sshpkt_add_padding(struct ssh *ssh, u_char pad)
2701 {
2702 	ssh->state->extra_pad = pad;
2703 	return 0;
2704 }
2705