xref: /openssh-portable/packet.c (revision c77bc73c)
1 /* $OpenBSD: packet.c,v 1.277 2018/07/16 03:09:13 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 <signal.h>
62 #include <time.h>
63 
64 /*
65  * Explicitly include OpenSSL before zlib as some versions of OpenSSL have
66  * "free_func" in their headers, which zlib typedefs.
67  */
68 #ifdef WITH_OPENSSL
69 # include <openssl/bn.h>
70 # include <openssl/evp.h>
71 # ifdef OPENSSL_HAS_ECC
72 #  include <openssl/ec.h>
73 # endif
74 #endif
75 
76 #include <zlib.h>
77 
78 #include "xmalloc.h"
79 #include "crc32.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 	    (state->input = sshbuf_new()) == NULL ||
232 	    (state->output = sshbuf_new()) == NULL ||
233 	    (state->outgoing_packet = sshbuf_new()) == NULL ||
234 	    (state->incoming_packet = sshbuf_new()) == NULL)
235 		goto fail;
236 	TAILQ_INIT(&state->outgoing);
237 	TAILQ_INIT(&ssh->private_keys);
238 	TAILQ_INIT(&ssh->public_keys);
239 	state->connection_in = -1;
240 	state->connection_out = -1;
241 	state->max_packet_size = 32768;
242 	state->packet_timeout_ms = -1;
243 	state->p_send.packets = state->p_read.packets = 0;
244 	state->initialized = 1;
245 	/*
246 	 * ssh_packet_send2() needs to queue packets until
247 	 * we've done the initial key exchange.
248 	 */
249 	state->rekeying = 1;
250 	ssh->state = state;
251 	return ssh;
252  fail:
253 	if (state) {
254 		sshbuf_free(state->input);
255 		sshbuf_free(state->output);
256 		sshbuf_free(state->incoming_packet);
257 		sshbuf_free(state->outgoing_packet);
258 		free(state);
259 	}
260 	free(ssh);
261 	return NULL;
262 }
263 
264 void
265 ssh_packet_set_input_hook(struct ssh *ssh, ssh_packet_hook_fn *hook, void *ctx)
266 {
267 	ssh->state->hook_in = hook;
268 	ssh->state->hook_in_ctx = ctx;
269 }
270 
271 /* Returns nonzero if rekeying is in progress */
272 int
273 ssh_packet_is_rekeying(struct ssh *ssh)
274 {
275 	return ssh->state->rekeying ||
276 	    (ssh->kex != NULL && ssh->kex->done == 0);
277 }
278 
279 /*
280  * Sets the descriptors used for communication.
281  */
282 struct ssh *
283 ssh_packet_set_connection(struct ssh *ssh, int fd_in, int fd_out)
284 {
285 	struct session_state *state;
286 	const struct sshcipher *none = cipher_by_name("none");
287 	int r;
288 
289 	if (none == NULL) {
290 		error("%s: cannot load cipher 'none'", __func__);
291 		return NULL;
292 	}
293 	if (ssh == NULL)
294 		ssh = ssh_alloc_session_state();
295 	if (ssh == NULL) {
296 		error("%s: cound not allocate state", __func__);
297 		return NULL;
298 	}
299 	state = ssh->state;
300 	state->connection_in = fd_in;
301 	state->connection_out = fd_out;
302 	if ((r = cipher_init(&state->send_context, none,
303 	    (const u_char *)"", 0, NULL, 0, CIPHER_ENCRYPT)) != 0 ||
304 	    (r = cipher_init(&state->receive_context, none,
305 	    (const u_char *)"", 0, NULL, 0, CIPHER_DECRYPT)) != 0) {
306 		error("%s: cipher_init failed: %s", __func__, ssh_err(r));
307 		free(ssh); /* XXX need ssh_free_session_state? */
308 		return NULL;
309 	}
310 	state->newkeys[MODE_IN] = state->newkeys[MODE_OUT] = NULL;
311 	/*
312 	 * Cache the IP address of the remote connection for use in error
313 	 * messages that might be generated after the connection has closed.
314 	 */
315 	(void)ssh_remote_ipaddr(ssh);
316 	return ssh;
317 }
318 
319 void
320 ssh_packet_set_timeout(struct ssh *ssh, int timeout, int count)
321 {
322 	struct session_state *state = ssh->state;
323 
324 	if (timeout <= 0 || count <= 0) {
325 		state->packet_timeout_ms = -1;
326 		return;
327 	}
328 	if ((INT_MAX / 1000) / count < timeout)
329 		state->packet_timeout_ms = INT_MAX;
330 	else
331 		state->packet_timeout_ms = timeout * count * 1000;
332 }
333 
334 void
335 ssh_packet_set_mux(struct ssh *ssh)
336 {
337 	ssh->state->mux = 1;
338 	ssh->state->rekeying = 0;
339 }
340 
341 int
342 ssh_packet_get_mux(struct ssh *ssh)
343 {
344 	return ssh->state->mux;
345 }
346 
347 int
348 ssh_packet_set_log_preamble(struct ssh *ssh, const char *fmt, ...)
349 {
350 	va_list args;
351 	int r;
352 
353 	free(ssh->log_preamble);
354 	if (fmt == NULL)
355 		ssh->log_preamble = NULL;
356 	else {
357 		va_start(args, fmt);
358 		r = vasprintf(&ssh->log_preamble, fmt, args);
359 		va_end(args);
360 		if (r < 0 || ssh->log_preamble == NULL)
361 			return SSH_ERR_ALLOC_FAIL;
362 	}
363 	return 0;
364 }
365 
366 int
367 ssh_packet_stop_discard(struct ssh *ssh)
368 {
369 	struct session_state *state = ssh->state;
370 	int r;
371 
372 	if (state->packet_discard_mac) {
373 		char buf[1024];
374 		size_t dlen = PACKET_MAX_SIZE;
375 
376 		if (dlen > state->packet_discard_mac_already)
377 			dlen -= state->packet_discard_mac_already;
378 		memset(buf, 'a', sizeof(buf));
379 		while (sshbuf_len(state->incoming_packet) < dlen)
380 			if ((r = sshbuf_put(state->incoming_packet, buf,
381 			    sizeof(buf))) != 0)
382 				return r;
383 		(void) mac_compute(state->packet_discard_mac,
384 		    state->p_read.seqnr,
385 		    sshbuf_ptr(state->incoming_packet), dlen,
386 		    NULL, 0);
387 	}
388 	logit("Finished discarding for %.200s port %d",
389 	    ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
390 	return SSH_ERR_MAC_INVALID;
391 }
392 
393 static int
394 ssh_packet_start_discard(struct ssh *ssh, struct sshenc *enc,
395     struct sshmac *mac, size_t mac_already, u_int discard)
396 {
397 	struct session_state *state = ssh->state;
398 	int r;
399 
400 	if (enc == NULL || !cipher_is_cbc(enc->cipher) || (mac && mac->etm)) {
401 		if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0)
402 			return r;
403 		return SSH_ERR_MAC_INVALID;
404 	}
405 	/*
406 	 * Record number of bytes over which the mac has already
407 	 * been computed in order to minimize timing attacks.
408 	 */
409 	if (mac && mac->enabled) {
410 		state->packet_discard_mac = mac;
411 		state->packet_discard_mac_already = mac_already;
412 	}
413 	if (sshbuf_len(state->input) >= discard)
414 		return ssh_packet_stop_discard(ssh);
415 	state->packet_discard = discard - sshbuf_len(state->input);
416 	return 0;
417 }
418 
419 /* Returns 1 if remote host is connected via socket, 0 if not. */
420 
421 int
422 ssh_packet_connection_is_on_socket(struct ssh *ssh)
423 {
424 	struct session_state *state;
425 	struct sockaddr_storage from, to;
426 	socklen_t fromlen, tolen;
427 
428 	if (ssh == NULL || ssh->state == NULL)
429 		return 0;
430 
431 	state = ssh->state;
432 	if (state->connection_in == -1 || state->connection_out == -1)
433 		return 0;
434 	/* filedescriptors in and out are the same, so it's a socket */
435 	if (state->connection_in == state->connection_out)
436 		return 1;
437 	fromlen = sizeof(from);
438 	memset(&from, 0, sizeof(from));
439 	if (getpeername(state->connection_in, (struct sockaddr *)&from,
440 	    &fromlen) < 0)
441 		return 0;
442 	tolen = sizeof(to);
443 	memset(&to, 0, sizeof(to));
444 	if (getpeername(state->connection_out, (struct sockaddr *)&to,
445 	    &tolen) < 0)
446 		return 0;
447 	if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0)
448 		return 0;
449 	if (from.ss_family != AF_INET && from.ss_family != AF_INET6)
450 		return 0;
451 	return 1;
452 }
453 
454 void
455 ssh_packet_get_bytes(struct ssh *ssh, u_int64_t *ibytes, u_int64_t *obytes)
456 {
457 	if (ibytes)
458 		*ibytes = ssh->state->p_read.bytes;
459 	if (obytes)
460 		*obytes = ssh->state->p_send.bytes;
461 }
462 
463 int
464 ssh_packet_connection_af(struct ssh *ssh)
465 {
466 	struct sockaddr_storage to;
467 	socklen_t tolen = sizeof(to);
468 
469 	memset(&to, 0, sizeof(to));
470 	if (getsockname(ssh->state->connection_out, (struct sockaddr *)&to,
471 	    &tolen) < 0)
472 		return 0;
473 #ifdef IPV4_IN_IPV6
474 	if (to.ss_family == AF_INET6 &&
475 	    IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)&to)->sin6_addr))
476 		return AF_INET;
477 #endif
478 	return to.ss_family;
479 }
480 
481 /* Sets the connection into non-blocking mode. */
482 
483 void
484 ssh_packet_set_nonblocking(struct ssh *ssh)
485 {
486 	/* Set the socket into non-blocking mode. */
487 	set_nonblock(ssh->state->connection_in);
488 
489 	if (ssh->state->connection_out != ssh->state->connection_in)
490 		set_nonblock(ssh->state->connection_out);
491 }
492 
493 /* Returns the socket used for reading. */
494 
495 int
496 ssh_packet_get_connection_in(struct ssh *ssh)
497 {
498 	return ssh->state->connection_in;
499 }
500 
501 /* Returns the descriptor used for writing. */
502 
503 int
504 ssh_packet_get_connection_out(struct ssh *ssh)
505 {
506 	return ssh->state->connection_out;
507 }
508 
509 /*
510  * Returns the IP-address of the remote host as a string.  The returned
511  * string must not be freed.
512  */
513 
514 const char *
515 ssh_remote_ipaddr(struct ssh *ssh)
516 {
517 	int sock;
518 
519 	/* Check whether we have cached the ipaddr. */
520 	if (ssh->remote_ipaddr == NULL) {
521 		if (ssh_packet_connection_is_on_socket(ssh)) {
522 			sock = ssh->state->connection_in;
523 			ssh->remote_ipaddr = get_peer_ipaddr(sock);
524 			ssh->remote_port = get_peer_port(sock);
525 			ssh->local_ipaddr = get_local_ipaddr(sock);
526 			ssh->local_port = get_local_port(sock);
527 		} else {
528 			ssh->remote_ipaddr = strdup("UNKNOWN");
529 			ssh->remote_port = 65535;
530 			ssh->local_ipaddr = strdup("UNKNOWN");
531 			ssh->local_port = 65535;
532 		}
533 	}
534 	return ssh->remote_ipaddr;
535 }
536 
537 /* Returns the port number of the remote host. */
538 
539 int
540 ssh_remote_port(struct ssh *ssh)
541 {
542 	(void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */
543 	return ssh->remote_port;
544 }
545 
546 /*
547  * Returns the IP-address of the local host as a string.  The returned
548  * string must not be freed.
549  */
550 
551 const char *
552 ssh_local_ipaddr(struct ssh *ssh)
553 {
554 	(void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */
555 	return ssh->local_ipaddr;
556 }
557 
558 /* Returns the port number of the local host. */
559 
560 int
561 ssh_local_port(struct ssh *ssh)
562 {
563 	(void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */
564 	return ssh->local_port;
565 }
566 
567 /* Returns the routing domain of the input socket, or NULL if unavailable */
568 const char *
569 ssh_packet_rdomain_in(struct ssh *ssh)
570 {
571 	if (ssh->rdomain_in != NULL)
572 		return ssh->rdomain_in;
573 	if (!ssh_packet_connection_is_on_socket(ssh))
574 		return NULL;
575 	ssh->rdomain_in = get_rdomain(ssh->state->connection_in);
576 	return ssh->rdomain_in;
577 }
578 
579 /* Closes the connection and clears and frees internal data structures. */
580 
581 static void
582 ssh_packet_close_internal(struct ssh *ssh, int do_close)
583 {
584 	struct session_state *state = ssh->state;
585 	u_int mode;
586 
587 	if (!state->initialized)
588 		return;
589 	state->initialized = 0;
590 	if (do_close) {
591 		if (state->connection_in == state->connection_out) {
592 			close(state->connection_out);
593 		} else {
594 			close(state->connection_in);
595 			close(state->connection_out);
596 		}
597 	}
598 	sshbuf_free(state->input);
599 	sshbuf_free(state->output);
600 	sshbuf_free(state->outgoing_packet);
601 	sshbuf_free(state->incoming_packet);
602 	for (mode = 0; mode < MODE_MAX; mode++) {
603 		kex_free_newkeys(state->newkeys[mode]);	/* current keys */
604 		state->newkeys[mode] = NULL;
605 		ssh_clear_newkeys(ssh, mode);		/* next keys */
606 	}
607 	/* compression state is in shared mem, so we can only release it once */
608 	if (do_close && state->compression_buffer) {
609 		sshbuf_free(state->compression_buffer);
610 		if (state->compression_out_started) {
611 			z_streamp stream = &state->compression_out_stream;
612 			debug("compress outgoing: "
613 			    "raw data %llu, compressed %llu, factor %.2f",
614 				(unsigned long long)stream->total_in,
615 				(unsigned long long)stream->total_out,
616 				stream->total_in == 0 ? 0.0 :
617 				(double) stream->total_out / stream->total_in);
618 			if (state->compression_out_failures == 0)
619 				deflateEnd(stream);
620 		}
621 		if (state->compression_in_started) {
622 			z_streamp stream = &state->compression_in_stream;
623 			debug("compress incoming: "
624 			    "raw data %llu, compressed %llu, factor %.2f",
625 			    (unsigned long long)stream->total_out,
626 			    (unsigned long long)stream->total_in,
627 			    stream->total_out == 0 ? 0.0 :
628 			    (double) stream->total_in / stream->total_out);
629 			if (state->compression_in_failures == 0)
630 				inflateEnd(stream);
631 		}
632 	}
633 	cipher_free(state->send_context);
634 	cipher_free(state->receive_context);
635 	state->send_context = state->receive_context = NULL;
636 	if (do_close) {
637 		free(ssh->local_ipaddr);
638 		ssh->local_ipaddr = NULL;
639 		free(ssh->remote_ipaddr);
640 		ssh->remote_ipaddr = NULL;
641 		free(ssh->state);
642 		ssh->state = NULL;
643 	}
644 }
645 
646 void
647 ssh_packet_close(struct ssh *ssh)
648 {
649 	ssh_packet_close_internal(ssh, 1);
650 }
651 
652 void
653 ssh_packet_clear_keys(struct ssh *ssh)
654 {
655 	ssh_packet_close_internal(ssh, 0);
656 }
657 
658 /* Sets remote side protocol flags. */
659 
660 void
661 ssh_packet_set_protocol_flags(struct ssh *ssh, u_int protocol_flags)
662 {
663 	ssh->state->remote_protocol_flags = protocol_flags;
664 }
665 
666 /* Returns the remote protocol flags set earlier by the above function. */
667 
668 u_int
669 ssh_packet_get_protocol_flags(struct ssh *ssh)
670 {
671 	return ssh->state->remote_protocol_flags;
672 }
673 
674 /*
675  * Starts packet compression from the next packet on in both directions.
676  * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip.
677  */
678 
679 static int
680 ssh_packet_init_compression(struct ssh *ssh)
681 {
682 	if (!ssh->state->compression_buffer &&
683 	   ((ssh->state->compression_buffer = sshbuf_new()) == NULL))
684 		return SSH_ERR_ALLOC_FAIL;
685 	return 0;
686 }
687 
688 static int
689 start_compression_out(struct ssh *ssh, int level)
690 {
691 	if (level < 1 || level > 9)
692 		return SSH_ERR_INVALID_ARGUMENT;
693 	debug("Enabling compression at level %d.", level);
694 	if (ssh->state->compression_out_started == 1)
695 		deflateEnd(&ssh->state->compression_out_stream);
696 	switch (deflateInit(&ssh->state->compression_out_stream, level)) {
697 	case Z_OK:
698 		ssh->state->compression_out_started = 1;
699 		break;
700 	case Z_MEM_ERROR:
701 		return SSH_ERR_ALLOC_FAIL;
702 	default:
703 		return SSH_ERR_INTERNAL_ERROR;
704 	}
705 	return 0;
706 }
707 
708 static int
709 start_compression_in(struct ssh *ssh)
710 {
711 	if (ssh->state->compression_in_started == 1)
712 		inflateEnd(&ssh->state->compression_in_stream);
713 	switch (inflateInit(&ssh->state->compression_in_stream)) {
714 	case Z_OK:
715 		ssh->state->compression_in_started = 1;
716 		break;
717 	case Z_MEM_ERROR:
718 		return SSH_ERR_ALLOC_FAIL;
719 	default:
720 		return SSH_ERR_INTERNAL_ERROR;
721 	}
722 	return 0;
723 }
724 
725 /* XXX remove need for separate compression buffer */
726 static int
727 compress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out)
728 {
729 	u_char buf[4096];
730 	int r, status;
731 
732 	if (ssh->state->compression_out_started != 1)
733 		return SSH_ERR_INTERNAL_ERROR;
734 
735 	/* This case is not handled below. */
736 	if (sshbuf_len(in) == 0)
737 		return 0;
738 
739 	/* Input is the contents of the input buffer. */
740 	if ((ssh->state->compression_out_stream.next_in =
741 	    sshbuf_mutable_ptr(in)) == NULL)
742 		return SSH_ERR_INTERNAL_ERROR;
743 	ssh->state->compression_out_stream.avail_in = sshbuf_len(in);
744 
745 	/* Loop compressing until deflate() returns with avail_out != 0. */
746 	do {
747 		/* Set up fixed-size output buffer. */
748 		ssh->state->compression_out_stream.next_out = buf;
749 		ssh->state->compression_out_stream.avail_out = sizeof(buf);
750 
751 		/* Compress as much data into the buffer as possible. */
752 		status = deflate(&ssh->state->compression_out_stream,
753 		    Z_PARTIAL_FLUSH);
754 		switch (status) {
755 		case Z_MEM_ERROR:
756 			return SSH_ERR_ALLOC_FAIL;
757 		case Z_OK:
758 			/* Append compressed data to output_buffer. */
759 			if ((r = sshbuf_put(out, buf, sizeof(buf) -
760 			    ssh->state->compression_out_stream.avail_out)) != 0)
761 				return r;
762 			break;
763 		case Z_STREAM_ERROR:
764 		default:
765 			ssh->state->compression_out_failures++;
766 			return SSH_ERR_INVALID_FORMAT;
767 		}
768 	} while (ssh->state->compression_out_stream.avail_out == 0);
769 	return 0;
770 }
771 
772 static int
773 uncompress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out)
774 {
775 	u_char buf[4096];
776 	int r, status;
777 
778 	if (ssh->state->compression_in_started != 1)
779 		return SSH_ERR_INTERNAL_ERROR;
780 
781 	if ((ssh->state->compression_in_stream.next_in =
782 	    sshbuf_mutable_ptr(in)) == NULL)
783 		return SSH_ERR_INTERNAL_ERROR;
784 	ssh->state->compression_in_stream.avail_in = sshbuf_len(in);
785 
786 	for (;;) {
787 		/* Set up fixed-size output buffer. */
788 		ssh->state->compression_in_stream.next_out = buf;
789 		ssh->state->compression_in_stream.avail_out = sizeof(buf);
790 
791 		status = inflate(&ssh->state->compression_in_stream,
792 		    Z_PARTIAL_FLUSH);
793 		switch (status) {
794 		case Z_OK:
795 			if ((r = sshbuf_put(out, buf, sizeof(buf) -
796 			    ssh->state->compression_in_stream.avail_out)) != 0)
797 				return r;
798 			break;
799 		case Z_BUF_ERROR:
800 			/*
801 			 * Comments in zlib.h say that we should keep calling
802 			 * inflate() until we get an error.  This appears to
803 			 * be the error that we get.
804 			 */
805 			return 0;
806 		case Z_DATA_ERROR:
807 			return SSH_ERR_INVALID_FORMAT;
808 		case Z_MEM_ERROR:
809 			return SSH_ERR_ALLOC_FAIL;
810 		case Z_STREAM_ERROR:
811 		default:
812 			ssh->state->compression_in_failures++;
813 			return SSH_ERR_INTERNAL_ERROR;
814 		}
815 	}
816 	/* NOTREACHED */
817 }
818 
819 void
820 ssh_clear_newkeys(struct ssh *ssh, int mode)
821 {
822 	if (ssh->kex && ssh->kex->newkeys[mode]) {
823 		kex_free_newkeys(ssh->kex->newkeys[mode]);
824 		ssh->kex->newkeys[mode] = NULL;
825 	}
826 }
827 
828 int
829 ssh_set_newkeys(struct ssh *ssh, int mode)
830 {
831 	struct session_state *state = ssh->state;
832 	struct sshenc *enc;
833 	struct sshmac *mac;
834 	struct sshcomp *comp;
835 	struct sshcipher_ctx **ccp;
836 	struct packet_state *ps;
837 	u_int64_t *max_blocks;
838 	const char *wmsg;
839 	int r, crypt_type;
840 
841 	debug2("set_newkeys: mode %d", mode);
842 
843 	if (mode == MODE_OUT) {
844 		ccp = &state->send_context;
845 		crypt_type = CIPHER_ENCRYPT;
846 		ps = &state->p_send;
847 		max_blocks = &state->max_blocks_out;
848 	} else {
849 		ccp = &state->receive_context;
850 		crypt_type = CIPHER_DECRYPT;
851 		ps = &state->p_read;
852 		max_blocks = &state->max_blocks_in;
853 	}
854 	if (state->newkeys[mode] != NULL) {
855 		debug("set_newkeys: rekeying, input %llu bytes %llu blocks, "
856 		   "output %llu bytes %llu blocks",
857 		   (unsigned long long)state->p_read.bytes,
858 		   (unsigned long long)state->p_read.blocks,
859 		   (unsigned long long)state->p_send.bytes,
860 		   (unsigned long long)state->p_send.blocks);
861 		cipher_free(*ccp);
862 		*ccp = NULL;
863 		kex_free_newkeys(state->newkeys[mode]);
864 		state->newkeys[mode] = NULL;
865 	}
866 	/* note that both bytes and the seqnr are not reset */
867 	ps->packets = ps->blocks = 0;
868 	/* move newkeys from kex to state */
869 	if ((state->newkeys[mode] = ssh->kex->newkeys[mode]) == NULL)
870 		return SSH_ERR_INTERNAL_ERROR;
871 	ssh->kex->newkeys[mode] = NULL;
872 	enc  = &state->newkeys[mode]->enc;
873 	mac  = &state->newkeys[mode]->mac;
874 	comp = &state->newkeys[mode]->comp;
875 	if (cipher_authlen(enc->cipher) == 0) {
876 		if ((r = mac_init(mac)) != 0)
877 			return r;
878 	}
879 	mac->enabled = 1;
880 	DBG(debug("cipher_init_context: %d", mode));
881 	if ((r = cipher_init(ccp, enc->cipher, enc->key, enc->key_len,
882 	    enc->iv, enc->iv_len, crypt_type)) != 0)
883 		return r;
884 	if (!state->cipher_warning_done &&
885 	    (wmsg = cipher_warning_message(*ccp)) != NULL) {
886 		error("Warning: %s", wmsg);
887 		state->cipher_warning_done = 1;
888 	}
889 	/* Deleting the keys does not gain extra security */
890 	/* explicit_bzero(enc->iv,  enc->block_size);
891 	   explicit_bzero(enc->key, enc->key_len);
892 	   explicit_bzero(mac->key, mac->key_len); */
893 	if ((comp->type == COMP_ZLIB ||
894 	    (comp->type == COMP_DELAYED &&
895 	     state->after_authentication)) && comp->enabled == 0) {
896 		if ((r = ssh_packet_init_compression(ssh)) < 0)
897 			return r;
898 		if (mode == MODE_OUT) {
899 			if ((r = start_compression_out(ssh, 6)) != 0)
900 				return r;
901 		} else {
902 			if ((r = start_compression_in(ssh)) != 0)
903 				return r;
904 		}
905 		comp->enabled = 1;
906 	}
907 	/*
908 	 * The 2^(blocksize*2) limit is too expensive for 3DES,
909 	 * so enforce a 1GB limit for small blocksizes.
910 	 * See RFC4344 section 3.2.
911 	 */
912 	if (enc->block_size >= 16)
913 		*max_blocks = (u_int64_t)1 << (enc->block_size*2);
914 	else
915 		*max_blocks = ((u_int64_t)1 << 30) / enc->block_size;
916 	if (state->rekey_limit)
917 		*max_blocks = MINIMUM(*max_blocks,
918 		    state->rekey_limit / enc->block_size);
919 	debug("rekey after %llu blocks", (unsigned long long)*max_blocks);
920 	return 0;
921 }
922 
923 #define MAX_PACKETS	(1U<<31)
924 static int
925 ssh_packet_need_rekeying(struct ssh *ssh, u_int outbound_packet_len)
926 {
927 	struct session_state *state = ssh->state;
928 	u_int32_t out_blocks;
929 
930 	/* XXX client can't cope with rekeying pre-auth */
931 	if (!state->after_authentication)
932 		return 0;
933 
934 	/* Haven't keyed yet or KEX in progress. */
935 	if (ssh->kex == NULL || ssh_packet_is_rekeying(ssh))
936 		return 0;
937 
938 	/* Peer can't rekey */
939 	if (ssh->compat & SSH_BUG_NOREKEY)
940 		return 0;
941 
942 	/*
943 	 * Permit one packet in or out per rekey - this allows us to
944 	 * make progress when rekey limits are very small.
945 	 */
946 	if (state->p_send.packets == 0 && state->p_read.packets == 0)
947 		return 0;
948 
949 	/* Time-based rekeying */
950 	if (state->rekey_interval != 0 &&
951 	    (int64_t)state->rekey_time + state->rekey_interval <= monotime())
952 		return 1;
953 
954 	/*
955 	 * Always rekey when MAX_PACKETS sent in either direction
956 	 * As per RFC4344 section 3.1 we do this after 2^31 packets.
957 	 */
958 	if (state->p_send.packets > MAX_PACKETS ||
959 	    state->p_read.packets > MAX_PACKETS)
960 		return 1;
961 
962 	/* Rekey after (cipher-specific) maximum blocks */
963 	out_blocks = ROUNDUP(outbound_packet_len,
964 	    state->newkeys[MODE_OUT]->enc.block_size);
965 	return (state->max_blocks_out &&
966 	    (state->p_send.blocks + out_blocks > state->max_blocks_out)) ||
967 	    (state->max_blocks_in &&
968 	    (state->p_read.blocks > state->max_blocks_in));
969 }
970 
971 /*
972  * Delayed compression for SSH2 is enabled after authentication:
973  * This happens on the server side after a SSH2_MSG_USERAUTH_SUCCESS is sent,
974  * and on the client side after a SSH2_MSG_USERAUTH_SUCCESS is received.
975  */
976 static int
977 ssh_packet_enable_delayed_compress(struct ssh *ssh)
978 {
979 	struct session_state *state = ssh->state;
980 	struct sshcomp *comp = NULL;
981 	int r, mode;
982 
983 	/*
984 	 * Remember that we are past the authentication step, so rekeying
985 	 * with COMP_DELAYED will turn on compression immediately.
986 	 */
987 	state->after_authentication = 1;
988 	for (mode = 0; mode < MODE_MAX; mode++) {
989 		/* protocol error: USERAUTH_SUCCESS received before NEWKEYS */
990 		if (state->newkeys[mode] == NULL)
991 			continue;
992 		comp = &state->newkeys[mode]->comp;
993 		if (comp && !comp->enabled && comp->type == COMP_DELAYED) {
994 			if ((r = ssh_packet_init_compression(ssh)) != 0)
995 				return r;
996 			if (mode == MODE_OUT) {
997 				if ((r = start_compression_out(ssh, 6)) != 0)
998 					return r;
999 			} else {
1000 				if ((r = start_compression_in(ssh)) != 0)
1001 					return r;
1002 			}
1003 			comp->enabled = 1;
1004 		}
1005 	}
1006 	return 0;
1007 }
1008 
1009 /* Used to mute debug logging for noisy packet types */
1010 int
1011 ssh_packet_log_type(u_char type)
1012 {
1013 	switch (type) {
1014 	case SSH2_MSG_CHANNEL_DATA:
1015 	case SSH2_MSG_CHANNEL_EXTENDED_DATA:
1016 	case SSH2_MSG_CHANNEL_WINDOW_ADJUST:
1017 		return 0;
1018 	default:
1019 		return 1;
1020 	}
1021 }
1022 
1023 /*
1024  * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue)
1025  */
1026 int
1027 ssh_packet_send2_wrapped(struct ssh *ssh)
1028 {
1029 	struct session_state *state = ssh->state;
1030 	u_char type, *cp, macbuf[SSH_DIGEST_MAX_LENGTH];
1031 	u_char tmp, padlen, pad = 0;
1032 	u_int authlen = 0, aadlen = 0;
1033 	u_int len;
1034 	struct sshenc *enc   = NULL;
1035 	struct sshmac *mac   = NULL;
1036 	struct sshcomp *comp = NULL;
1037 	int r, block_size;
1038 
1039 	if (state->newkeys[MODE_OUT] != NULL) {
1040 		enc  = &state->newkeys[MODE_OUT]->enc;
1041 		mac  = &state->newkeys[MODE_OUT]->mac;
1042 		comp = &state->newkeys[MODE_OUT]->comp;
1043 		/* disable mac for authenticated encryption */
1044 		if ((authlen = cipher_authlen(enc->cipher)) != 0)
1045 			mac = NULL;
1046 	}
1047 	block_size = enc ? enc->block_size : 8;
1048 	aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0;
1049 
1050 	type = (sshbuf_ptr(state->outgoing_packet))[5];
1051 	if (ssh_packet_log_type(type))
1052 		debug3("send packet: type %u", type);
1053 #ifdef PACKET_DEBUG
1054 	fprintf(stderr, "plain:     ");
1055 	sshbuf_dump(state->outgoing_packet, stderr);
1056 #endif
1057 
1058 	if (comp && comp->enabled) {
1059 		len = sshbuf_len(state->outgoing_packet);
1060 		/* skip header, compress only payload */
1061 		if ((r = sshbuf_consume(state->outgoing_packet, 5)) != 0)
1062 			goto out;
1063 		sshbuf_reset(state->compression_buffer);
1064 		if ((r = compress_buffer(ssh, state->outgoing_packet,
1065 		    state->compression_buffer)) != 0)
1066 			goto out;
1067 		sshbuf_reset(state->outgoing_packet);
1068 		if ((r = sshbuf_put(state->outgoing_packet,
1069 		    "\0\0\0\0\0", 5)) != 0 ||
1070 		    (r = sshbuf_putb(state->outgoing_packet,
1071 		    state->compression_buffer)) != 0)
1072 			goto out;
1073 		DBG(debug("compression: raw %d compressed %zd", len,
1074 		    sshbuf_len(state->outgoing_packet)));
1075 	}
1076 
1077 	/* sizeof (packet_len + pad_len + payload) */
1078 	len = sshbuf_len(state->outgoing_packet);
1079 
1080 	/*
1081 	 * calc size of padding, alloc space, get random data,
1082 	 * minimum padding is 4 bytes
1083 	 */
1084 	len -= aadlen; /* packet length is not encrypted for EtM modes */
1085 	padlen = block_size - (len % block_size);
1086 	if (padlen < 4)
1087 		padlen += block_size;
1088 	if (state->extra_pad) {
1089 		tmp = state->extra_pad;
1090 		state->extra_pad =
1091 		    ROUNDUP(state->extra_pad, block_size);
1092 		/* check if roundup overflowed */
1093 		if (state->extra_pad < tmp)
1094 			return SSH_ERR_INVALID_ARGUMENT;
1095 		tmp = (len + padlen) % state->extra_pad;
1096 		/* Check whether pad calculation below will underflow */
1097 		if (tmp > state->extra_pad)
1098 			return SSH_ERR_INVALID_ARGUMENT;
1099 		pad = state->extra_pad - tmp;
1100 		DBG(debug3("%s: adding %d (len %d padlen %d extra_pad %d)",
1101 		    __func__, pad, len, padlen, state->extra_pad));
1102 		tmp = padlen;
1103 		padlen += pad;
1104 		/* Check whether padlen calculation overflowed */
1105 		if (padlen < tmp)
1106 			return SSH_ERR_INVALID_ARGUMENT; /* overflow */
1107 		state->extra_pad = 0;
1108 	}
1109 	if ((r = sshbuf_reserve(state->outgoing_packet, padlen, &cp)) != 0)
1110 		goto out;
1111 	if (enc && !cipher_ctx_is_plaintext(state->send_context)) {
1112 		/* random padding */
1113 		arc4random_buf(cp, padlen);
1114 	} else {
1115 		/* clear padding */
1116 		explicit_bzero(cp, padlen);
1117 	}
1118 	/* sizeof (packet_len + pad_len + payload + padding) */
1119 	len = sshbuf_len(state->outgoing_packet);
1120 	cp = sshbuf_mutable_ptr(state->outgoing_packet);
1121 	if (cp == NULL) {
1122 		r = SSH_ERR_INTERNAL_ERROR;
1123 		goto out;
1124 	}
1125 	/* packet_length includes payload, padding and padding length field */
1126 	POKE_U32(cp, len - 4);
1127 	cp[4] = padlen;
1128 	DBG(debug("send: len %d (includes padlen %d, aadlen %d)",
1129 	    len, padlen, aadlen));
1130 
1131 	/* compute MAC over seqnr and packet(length fields, payload, padding) */
1132 	if (mac && mac->enabled && !mac->etm) {
1133 		if ((r = mac_compute(mac, state->p_send.seqnr,
1134 		    sshbuf_ptr(state->outgoing_packet), len,
1135 		    macbuf, sizeof(macbuf))) != 0)
1136 			goto out;
1137 		DBG(debug("done calc MAC out #%d", state->p_send.seqnr));
1138 	}
1139 	/* encrypt packet and append to output buffer. */
1140 	if ((r = sshbuf_reserve(state->output,
1141 	    sshbuf_len(state->outgoing_packet) + authlen, &cp)) != 0)
1142 		goto out;
1143 	if ((r = cipher_crypt(state->send_context, state->p_send.seqnr, cp,
1144 	    sshbuf_ptr(state->outgoing_packet),
1145 	    len - aadlen, aadlen, authlen)) != 0)
1146 		goto out;
1147 	/* append unencrypted MAC */
1148 	if (mac && mac->enabled) {
1149 		if (mac->etm) {
1150 			/* EtM: compute mac over aadlen + cipher text */
1151 			if ((r = mac_compute(mac, state->p_send.seqnr,
1152 			    cp, len, macbuf, sizeof(macbuf))) != 0)
1153 				goto out;
1154 			DBG(debug("done calc MAC(EtM) out #%d",
1155 			    state->p_send.seqnr));
1156 		}
1157 		if ((r = sshbuf_put(state->output, macbuf, mac->mac_len)) != 0)
1158 			goto out;
1159 	}
1160 #ifdef PACKET_DEBUG
1161 	fprintf(stderr, "encrypted: ");
1162 	sshbuf_dump(state->output, stderr);
1163 #endif
1164 	/* increment sequence number for outgoing packets */
1165 	if (++state->p_send.seqnr == 0)
1166 		logit("outgoing seqnr wraps around");
1167 	if (++state->p_send.packets == 0)
1168 		if (!(ssh->compat & SSH_BUG_NOREKEY))
1169 			return SSH_ERR_NEED_REKEY;
1170 	state->p_send.blocks += len / block_size;
1171 	state->p_send.bytes += len;
1172 	sshbuf_reset(state->outgoing_packet);
1173 
1174 	if (type == SSH2_MSG_NEWKEYS)
1175 		r = ssh_set_newkeys(ssh, MODE_OUT);
1176 	else if (type == SSH2_MSG_USERAUTH_SUCCESS && state->server_side)
1177 		r = ssh_packet_enable_delayed_compress(ssh);
1178 	else
1179 		r = 0;
1180  out:
1181 	return r;
1182 }
1183 
1184 /* returns non-zero if the specified packet type is usec by KEX */
1185 static int
1186 ssh_packet_type_is_kex(u_char type)
1187 {
1188 	return
1189 	    type >= SSH2_MSG_TRANSPORT_MIN &&
1190 	    type <= SSH2_MSG_TRANSPORT_MAX &&
1191 	    type != SSH2_MSG_SERVICE_REQUEST &&
1192 	    type != SSH2_MSG_SERVICE_ACCEPT &&
1193 	    type != SSH2_MSG_EXT_INFO;
1194 }
1195 
1196 int
1197 ssh_packet_send2(struct ssh *ssh)
1198 {
1199 	struct session_state *state = ssh->state;
1200 	struct packet *p;
1201 	u_char type;
1202 	int r, need_rekey;
1203 
1204 	if (sshbuf_len(state->outgoing_packet) < 6)
1205 		return SSH_ERR_INTERNAL_ERROR;
1206 	type = sshbuf_ptr(state->outgoing_packet)[5];
1207 	need_rekey = !ssh_packet_type_is_kex(type) &&
1208 	    ssh_packet_need_rekeying(ssh, sshbuf_len(state->outgoing_packet));
1209 
1210 	/*
1211 	 * During rekeying we can only send key exchange messages.
1212 	 * Queue everything else.
1213 	 */
1214 	if ((need_rekey || state->rekeying) && !ssh_packet_type_is_kex(type)) {
1215 		if (need_rekey)
1216 			debug3("%s: rekex triggered", __func__);
1217 		debug("enqueue packet: %u", type);
1218 		p = calloc(1, sizeof(*p));
1219 		if (p == NULL)
1220 			return SSH_ERR_ALLOC_FAIL;
1221 		p->type = type;
1222 		p->payload = state->outgoing_packet;
1223 		TAILQ_INSERT_TAIL(&state->outgoing, p, next);
1224 		state->outgoing_packet = sshbuf_new();
1225 		if (state->outgoing_packet == NULL)
1226 			return SSH_ERR_ALLOC_FAIL;
1227 		if (need_rekey) {
1228 			/*
1229 			 * This packet triggered a rekey, so send the
1230 			 * KEXINIT now.
1231 			 * NB. reenters this function via kex_start_rekex().
1232 			 */
1233 			return kex_start_rekex(ssh);
1234 		}
1235 		return 0;
1236 	}
1237 
1238 	/* rekeying starts with sending KEXINIT */
1239 	if (type == SSH2_MSG_KEXINIT)
1240 		state->rekeying = 1;
1241 
1242 	if ((r = ssh_packet_send2_wrapped(ssh)) != 0)
1243 		return r;
1244 
1245 	/* after a NEWKEYS message we can send the complete queue */
1246 	if (type == SSH2_MSG_NEWKEYS) {
1247 		state->rekeying = 0;
1248 		state->rekey_time = monotime();
1249 		while ((p = TAILQ_FIRST(&state->outgoing))) {
1250 			type = p->type;
1251 			/*
1252 			 * If this packet triggers a rekex, then skip the
1253 			 * remaining packets in the queue for now.
1254 			 * NB. re-enters this function via kex_start_rekex.
1255 			 */
1256 			if (ssh_packet_need_rekeying(ssh,
1257 			    sshbuf_len(p->payload))) {
1258 				debug3("%s: queued packet triggered rekex",
1259 				    __func__);
1260 				return kex_start_rekex(ssh);
1261 			}
1262 			debug("dequeue packet: %u", type);
1263 			sshbuf_free(state->outgoing_packet);
1264 			state->outgoing_packet = p->payload;
1265 			TAILQ_REMOVE(&state->outgoing, p, next);
1266 			memset(p, 0, sizeof(*p));
1267 			free(p);
1268 			if ((r = ssh_packet_send2_wrapped(ssh)) != 0)
1269 				return r;
1270 		}
1271 	}
1272 	return 0;
1273 }
1274 
1275 /*
1276  * Waits until a packet has been received, and returns its type.  Note that
1277  * no other data is processed until this returns, so this function should not
1278  * be used during the interactive session.
1279  */
1280 
1281 int
1282 ssh_packet_read_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
1283 {
1284 	struct session_state *state = ssh->state;
1285 	int len, r, ms_remain;
1286 	fd_set *setp;
1287 	char buf[8192];
1288 	struct timeval timeout, start, *timeoutp = NULL;
1289 
1290 	DBG(debug("packet_read()"));
1291 
1292 	setp = calloc(howmany(state->connection_in + 1,
1293 	    NFDBITS), sizeof(fd_mask));
1294 	if (setp == NULL)
1295 		return SSH_ERR_ALLOC_FAIL;
1296 
1297 	/*
1298 	 * Since we are blocking, ensure that all written packets have
1299 	 * been sent.
1300 	 */
1301 	if ((r = ssh_packet_write_wait(ssh)) != 0)
1302 		goto out;
1303 
1304 	/* Stay in the loop until we have received a complete packet. */
1305 	for (;;) {
1306 		/* Try to read a packet from the buffer. */
1307 		r = ssh_packet_read_poll_seqnr(ssh, typep, seqnr_p);
1308 		if (r != 0)
1309 			break;
1310 		/* If we got a packet, return it. */
1311 		if (*typep != SSH_MSG_NONE)
1312 			break;
1313 		/*
1314 		 * Otherwise, wait for some data to arrive, add it to the
1315 		 * buffer, and try again.
1316 		 */
1317 		memset(setp, 0, howmany(state->connection_in + 1,
1318 		    NFDBITS) * sizeof(fd_mask));
1319 		FD_SET(state->connection_in, setp);
1320 
1321 		if (state->packet_timeout_ms > 0) {
1322 			ms_remain = state->packet_timeout_ms;
1323 			timeoutp = &timeout;
1324 		}
1325 		/* Wait for some data to arrive. */
1326 		for (;;) {
1327 			if (state->packet_timeout_ms != -1) {
1328 				ms_to_timeval(&timeout, ms_remain);
1329 				monotime_tv(&start);
1330 			}
1331 			if ((r = select(state->connection_in + 1, setp,
1332 			    NULL, NULL, timeoutp)) >= 0)
1333 				break;
1334 			if (errno != EAGAIN && errno != EINTR &&
1335 			    errno != EWOULDBLOCK) {
1336 				r = SSH_ERR_SYSTEM_ERROR;
1337 				goto out;
1338 			}
1339 			if (state->packet_timeout_ms == -1)
1340 				continue;
1341 			ms_subtract_diff(&start, &ms_remain);
1342 			if (ms_remain <= 0) {
1343 				r = 0;
1344 				break;
1345 			}
1346 		}
1347 		if (r == 0) {
1348 			r = SSH_ERR_CONN_TIMEOUT;
1349 			goto out;
1350 		}
1351 		/* Read data from the socket. */
1352 		len = read(state->connection_in, buf, sizeof(buf));
1353 		if (len == 0) {
1354 			r = SSH_ERR_CONN_CLOSED;
1355 			goto out;
1356 		}
1357 		if (len < 0) {
1358 			r = SSH_ERR_SYSTEM_ERROR;
1359 			goto out;
1360 		}
1361 
1362 		/* Append it to the buffer. */
1363 		if ((r = ssh_packet_process_incoming(ssh, buf, len)) != 0)
1364 			goto out;
1365 	}
1366  out:
1367 	free(setp);
1368 	return r;
1369 }
1370 
1371 int
1372 ssh_packet_read(struct ssh *ssh)
1373 {
1374 	u_char type;
1375 	int r;
1376 
1377 	if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0)
1378 		fatal("%s: %s", __func__, ssh_err(r));
1379 	return type;
1380 }
1381 
1382 /*
1383  * Waits until a packet has been received, verifies that its type matches
1384  * that given, and gives a fatal error and exits if there is a mismatch.
1385  */
1386 
1387 int
1388 ssh_packet_read_expect(struct ssh *ssh, u_int expected_type)
1389 {
1390 	int r;
1391 	u_char type;
1392 
1393 	if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0)
1394 		return r;
1395 	if (type != expected_type) {
1396 		if ((r = sshpkt_disconnect(ssh,
1397 		    "Protocol error: expected packet type %d, got %d",
1398 		    expected_type, type)) != 0)
1399 			return r;
1400 		return SSH_ERR_PROTOCOL_ERROR;
1401 	}
1402 	return 0;
1403 }
1404 
1405 static int
1406 ssh_packet_read_poll2_mux(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
1407 {
1408 	struct session_state *state = ssh->state;
1409 	const u_char *cp;
1410 	size_t need;
1411 	int r;
1412 
1413 	if (ssh->kex)
1414 		return SSH_ERR_INTERNAL_ERROR;
1415 	*typep = SSH_MSG_NONE;
1416 	cp = sshbuf_ptr(state->input);
1417 	if (state->packlen == 0) {
1418 		if (sshbuf_len(state->input) < 4 + 1)
1419 			return 0; /* packet is incomplete */
1420 		state->packlen = PEEK_U32(cp);
1421 		if (state->packlen < 4 + 1 ||
1422 		    state->packlen > PACKET_MAX_SIZE)
1423 			return SSH_ERR_MESSAGE_INCOMPLETE;
1424 	}
1425 	need = state->packlen + 4;
1426 	if (sshbuf_len(state->input) < need)
1427 		return 0; /* packet is incomplete */
1428 	sshbuf_reset(state->incoming_packet);
1429 	if ((r = sshbuf_put(state->incoming_packet, cp + 4,
1430 	    state->packlen)) != 0 ||
1431 	    (r = sshbuf_consume(state->input, need)) != 0 ||
1432 	    (r = sshbuf_get_u8(state->incoming_packet, NULL)) != 0 ||
1433 	    (r = sshbuf_get_u8(state->incoming_packet, typep)) != 0)
1434 		return r;
1435 	if (ssh_packet_log_type(*typep))
1436 		debug3("%s: type %u", __func__, *typep);
1437 	/* sshbuf_dump(state->incoming_packet, stderr); */
1438 	/* reset for next packet */
1439 	state->packlen = 0;
1440 	return r;
1441 }
1442 
1443 int
1444 ssh_packet_read_poll2(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
1445 {
1446 	struct session_state *state = ssh->state;
1447 	u_int padlen, need;
1448 	u_char *cp;
1449 	u_int maclen, aadlen = 0, authlen = 0, block_size;
1450 	struct sshenc *enc   = NULL;
1451 	struct sshmac *mac   = NULL;
1452 	struct sshcomp *comp = NULL;
1453 	int r;
1454 
1455 	if (state->mux)
1456 		return ssh_packet_read_poll2_mux(ssh, typep, seqnr_p);
1457 
1458 	*typep = SSH_MSG_NONE;
1459 
1460 	if (state->packet_discard)
1461 		return 0;
1462 
1463 	if (state->newkeys[MODE_IN] != NULL) {
1464 		enc  = &state->newkeys[MODE_IN]->enc;
1465 		mac  = &state->newkeys[MODE_IN]->mac;
1466 		comp = &state->newkeys[MODE_IN]->comp;
1467 		/* disable mac for authenticated encryption */
1468 		if ((authlen = cipher_authlen(enc->cipher)) != 0)
1469 			mac = NULL;
1470 	}
1471 	maclen = mac && mac->enabled ? mac->mac_len : 0;
1472 	block_size = enc ? enc->block_size : 8;
1473 	aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0;
1474 
1475 	if (aadlen && state->packlen == 0) {
1476 		if (cipher_get_length(state->receive_context,
1477 		    &state->packlen, state->p_read.seqnr,
1478 		    sshbuf_ptr(state->input), sshbuf_len(state->input)) != 0)
1479 			return 0;
1480 		if (state->packlen < 1 + 4 ||
1481 		    state->packlen > PACKET_MAX_SIZE) {
1482 #ifdef PACKET_DEBUG
1483 			sshbuf_dump(state->input, stderr);
1484 #endif
1485 			logit("Bad packet length %u.", state->packlen);
1486 			if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0)
1487 				return r;
1488 			return SSH_ERR_CONN_CORRUPT;
1489 		}
1490 		sshbuf_reset(state->incoming_packet);
1491 	} else if (state->packlen == 0) {
1492 		/*
1493 		 * check if input size is less than the cipher block size,
1494 		 * decrypt first block and extract length of incoming packet
1495 		 */
1496 		if (sshbuf_len(state->input) < block_size)
1497 			return 0;
1498 		sshbuf_reset(state->incoming_packet);
1499 		if ((r = sshbuf_reserve(state->incoming_packet, block_size,
1500 		    &cp)) != 0)
1501 			goto out;
1502 		if ((r = cipher_crypt(state->receive_context,
1503 		    state->p_send.seqnr, cp, sshbuf_ptr(state->input),
1504 		    block_size, 0, 0)) != 0)
1505 			goto out;
1506 		state->packlen = PEEK_U32(sshbuf_ptr(state->incoming_packet));
1507 		if (state->packlen < 1 + 4 ||
1508 		    state->packlen > PACKET_MAX_SIZE) {
1509 #ifdef PACKET_DEBUG
1510 			fprintf(stderr, "input: \n");
1511 			sshbuf_dump(state->input, stderr);
1512 			fprintf(stderr, "incoming_packet: \n");
1513 			sshbuf_dump(state->incoming_packet, stderr);
1514 #endif
1515 			logit("Bad packet length %u.", state->packlen);
1516 			return ssh_packet_start_discard(ssh, enc, mac, 0,
1517 			    PACKET_MAX_SIZE);
1518 		}
1519 		if ((r = sshbuf_consume(state->input, block_size)) != 0)
1520 			goto out;
1521 	}
1522 	DBG(debug("input: packet len %u", state->packlen+4));
1523 
1524 	if (aadlen) {
1525 		/* only the payload is encrypted */
1526 		need = state->packlen;
1527 	} else {
1528 		/*
1529 		 * the payload size and the payload are encrypted, but we
1530 		 * have a partial packet of block_size bytes
1531 		 */
1532 		need = 4 + state->packlen - block_size;
1533 	}
1534 	DBG(debug("partial packet: block %d, need %d, maclen %d, authlen %d,"
1535 	    " aadlen %d", block_size, need, maclen, authlen, aadlen));
1536 	if (need % block_size != 0) {
1537 		logit("padding error: need %d block %d mod %d",
1538 		    need, block_size, need % block_size);
1539 		return ssh_packet_start_discard(ssh, enc, mac, 0,
1540 		    PACKET_MAX_SIZE - block_size);
1541 	}
1542 	/*
1543 	 * check if the entire packet has been received and
1544 	 * decrypt into incoming_packet:
1545 	 * 'aadlen' bytes are unencrypted, but authenticated.
1546 	 * 'need' bytes are encrypted, followed by either
1547 	 * 'authlen' bytes of authentication tag or
1548 	 * 'maclen' bytes of message authentication code.
1549 	 */
1550 	if (sshbuf_len(state->input) < aadlen + need + authlen + maclen)
1551 		return 0; /* packet is incomplete */
1552 #ifdef PACKET_DEBUG
1553 	fprintf(stderr, "read_poll enc/full: ");
1554 	sshbuf_dump(state->input, stderr);
1555 #endif
1556 	/* EtM: check mac over encrypted input */
1557 	if (mac && mac->enabled && mac->etm) {
1558 		if ((r = mac_check(mac, state->p_read.seqnr,
1559 		    sshbuf_ptr(state->input), aadlen + need,
1560 		    sshbuf_ptr(state->input) + aadlen + need + authlen,
1561 		    maclen)) != 0) {
1562 			if (r == SSH_ERR_MAC_INVALID)
1563 				logit("Corrupted MAC on input.");
1564 			goto out;
1565 		}
1566 	}
1567 	if ((r = sshbuf_reserve(state->incoming_packet, aadlen + need,
1568 	    &cp)) != 0)
1569 		goto out;
1570 	if ((r = cipher_crypt(state->receive_context, state->p_read.seqnr, cp,
1571 	    sshbuf_ptr(state->input), need, aadlen, authlen)) != 0)
1572 		goto out;
1573 	if ((r = sshbuf_consume(state->input, aadlen + need + authlen)) != 0)
1574 		goto out;
1575 	if (mac && mac->enabled) {
1576 		/* Not EtM: check MAC over cleartext */
1577 		if (!mac->etm && (r = mac_check(mac, state->p_read.seqnr,
1578 		    sshbuf_ptr(state->incoming_packet),
1579 		    sshbuf_len(state->incoming_packet),
1580 		    sshbuf_ptr(state->input), maclen)) != 0) {
1581 			if (r != SSH_ERR_MAC_INVALID)
1582 				goto out;
1583 			logit("Corrupted MAC on input.");
1584 			if (need + block_size > PACKET_MAX_SIZE)
1585 				return SSH_ERR_INTERNAL_ERROR;
1586 			return ssh_packet_start_discard(ssh, enc, mac,
1587 			    sshbuf_len(state->incoming_packet),
1588 			    PACKET_MAX_SIZE - need - block_size);
1589 		}
1590 		/* Remove MAC from input buffer */
1591 		DBG(debug("MAC #%d ok", state->p_read.seqnr));
1592 		if ((r = sshbuf_consume(state->input, mac->mac_len)) != 0)
1593 			goto out;
1594 	}
1595 	if (seqnr_p != NULL)
1596 		*seqnr_p = state->p_read.seqnr;
1597 	if (++state->p_read.seqnr == 0)
1598 		logit("incoming seqnr wraps around");
1599 	if (++state->p_read.packets == 0)
1600 		if (!(ssh->compat & SSH_BUG_NOREKEY))
1601 			return SSH_ERR_NEED_REKEY;
1602 	state->p_read.blocks += (state->packlen + 4) / block_size;
1603 	state->p_read.bytes += state->packlen + 4;
1604 
1605 	/* get padlen */
1606 	padlen = sshbuf_ptr(state->incoming_packet)[4];
1607 	DBG(debug("input: padlen %d", padlen));
1608 	if (padlen < 4)	{
1609 		if ((r = sshpkt_disconnect(ssh,
1610 		    "Corrupted padlen %d on input.", padlen)) != 0 ||
1611 		    (r = ssh_packet_write_wait(ssh)) != 0)
1612 			return r;
1613 		return SSH_ERR_CONN_CORRUPT;
1614 	}
1615 
1616 	/* skip packet size + padlen, discard padding */
1617 	if ((r = sshbuf_consume(state->incoming_packet, 4 + 1)) != 0 ||
1618 	    ((r = sshbuf_consume_end(state->incoming_packet, padlen)) != 0))
1619 		goto out;
1620 
1621 	DBG(debug("input: len before de-compress %zd",
1622 	    sshbuf_len(state->incoming_packet)));
1623 	if (comp && comp->enabled) {
1624 		sshbuf_reset(state->compression_buffer);
1625 		if ((r = uncompress_buffer(ssh, state->incoming_packet,
1626 		    state->compression_buffer)) != 0)
1627 			goto out;
1628 		sshbuf_reset(state->incoming_packet);
1629 		if ((r = sshbuf_putb(state->incoming_packet,
1630 		    state->compression_buffer)) != 0)
1631 			goto out;
1632 		DBG(debug("input: len after de-compress %zd",
1633 		    sshbuf_len(state->incoming_packet)));
1634 	}
1635 	/*
1636 	 * get packet type, implies consume.
1637 	 * return length of payload (without type field)
1638 	 */
1639 	if ((r = sshbuf_get_u8(state->incoming_packet, typep)) != 0)
1640 		goto out;
1641 	if (ssh_packet_log_type(*typep))
1642 		debug3("receive packet: type %u", *typep);
1643 	if (*typep < SSH2_MSG_MIN || *typep >= SSH2_MSG_LOCAL_MIN) {
1644 		if ((r = sshpkt_disconnect(ssh,
1645 		    "Invalid ssh2 packet type: %d", *typep)) != 0 ||
1646 		    (r = ssh_packet_write_wait(ssh)) != 0)
1647 			return r;
1648 		return SSH_ERR_PROTOCOL_ERROR;
1649 	}
1650 	if (state->hook_in != NULL &&
1651 	    (r = state->hook_in(ssh, state->incoming_packet, typep,
1652 	    state->hook_in_ctx)) != 0)
1653 		return r;
1654 	if (*typep == SSH2_MSG_USERAUTH_SUCCESS && !state->server_side)
1655 		r = ssh_packet_enable_delayed_compress(ssh);
1656 	else
1657 		r = 0;
1658 #ifdef PACKET_DEBUG
1659 	fprintf(stderr, "read/plain[%d]:\r\n", *typep);
1660 	sshbuf_dump(state->incoming_packet, stderr);
1661 #endif
1662 	/* reset for next packet */
1663 	state->packlen = 0;
1664 
1665 	/* do we need to rekey? */
1666 	if (ssh_packet_need_rekeying(ssh, 0)) {
1667 		debug3("%s: rekex triggered", __func__);
1668 		if ((r = kex_start_rekex(ssh)) != 0)
1669 			return r;
1670 	}
1671  out:
1672 	return r;
1673 }
1674 
1675 int
1676 ssh_packet_read_poll_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
1677 {
1678 	struct session_state *state = ssh->state;
1679 	u_int reason, seqnr;
1680 	int r;
1681 	u_char *msg;
1682 
1683 	for (;;) {
1684 		msg = NULL;
1685 		r = ssh_packet_read_poll2(ssh, typep, seqnr_p);
1686 		if (r != 0)
1687 			return r;
1688 		if (*typep) {
1689 			state->keep_alive_timeouts = 0;
1690 			DBG(debug("received packet type %d", *typep));
1691 		}
1692 		switch (*typep) {
1693 		case SSH2_MSG_IGNORE:
1694 			debug3("Received SSH2_MSG_IGNORE");
1695 			break;
1696 		case SSH2_MSG_DEBUG:
1697 			if ((r = sshpkt_get_u8(ssh, NULL)) != 0 ||
1698 			    (r = sshpkt_get_string(ssh, &msg, NULL)) != 0 ||
1699 			    (r = sshpkt_get_string(ssh, NULL, NULL)) != 0) {
1700 				free(msg);
1701 				return r;
1702 			}
1703 			debug("Remote: %.900s", msg);
1704 			free(msg);
1705 			break;
1706 		case SSH2_MSG_DISCONNECT:
1707 			if ((r = sshpkt_get_u32(ssh, &reason)) != 0 ||
1708 			    (r = sshpkt_get_string(ssh, &msg, NULL)) != 0)
1709 				return r;
1710 			/* Ignore normal client exit notifications */
1711 			do_log2(ssh->state->server_side &&
1712 			    reason == SSH2_DISCONNECT_BY_APPLICATION ?
1713 			    SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_ERROR,
1714 			    "Received disconnect from %s port %d:"
1715 			    "%u: %.400s", ssh_remote_ipaddr(ssh),
1716 			    ssh_remote_port(ssh), reason, msg);
1717 			free(msg);
1718 			return SSH_ERR_DISCONNECTED;
1719 		case SSH2_MSG_UNIMPLEMENTED:
1720 			if ((r = sshpkt_get_u32(ssh, &seqnr)) != 0)
1721 				return r;
1722 			debug("Received SSH2_MSG_UNIMPLEMENTED for %u",
1723 			    seqnr);
1724 			break;
1725 		default:
1726 			return 0;
1727 		}
1728 	}
1729 }
1730 
1731 /*
1732  * Buffers the given amount of input characters.  This is intended to be used
1733  * together with packet_read_poll.
1734  */
1735 
1736 int
1737 ssh_packet_process_incoming(struct ssh *ssh, const char *buf, u_int len)
1738 {
1739 	struct session_state *state = ssh->state;
1740 	int r;
1741 
1742 	if (state->packet_discard) {
1743 		state->keep_alive_timeouts = 0; /* ?? */
1744 		if (len >= state->packet_discard) {
1745 			if ((r = ssh_packet_stop_discard(ssh)) != 0)
1746 				return r;
1747 		}
1748 		state->packet_discard -= len;
1749 		return 0;
1750 	}
1751 	if ((r = sshbuf_put(ssh->state->input, buf, len)) != 0)
1752 		return r;
1753 
1754 	return 0;
1755 }
1756 
1757 int
1758 ssh_packet_remaining(struct ssh *ssh)
1759 {
1760 	return sshbuf_len(ssh->state->incoming_packet);
1761 }
1762 
1763 /*
1764  * Sends a diagnostic message from the server to the client.  This message
1765  * can be sent at any time (but not while constructing another message). The
1766  * message is printed immediately, but only if the client is being executed
1767  * in verbose mode.  These messages are primarily intended to ease debugging
1768  * authentication problems.   The length of the formatted message must not
1769  * exceed 1024 bytes.  This will automatically call ssh_packet_write_wait.
1770  */
1771 void
1772 ssh_packet_send_debug(struct ssh *ssh, const char *fmt,...)
1773 {
1774 	char buf[1024];
1775 	va_list args;
1776 	int r;
1777 
1778 	if ((ssh->compat & SSH_BUG_DEBUG))
1779 		return;
1780 
1781 	va_start(args, fmt);
1782 	vsnprintf(buf, sizeof(buf), fmt, args);
1783 	va_end(args);
1784 
1785 	debug3("sending debug message: %s", buf);
1786 
1787 	if ((r = sshpkt_start(ssh, SSH2_MSG_DEBUG)) != 0 ||
1788 	    (r = sshpkt_put_u8(ssh, 0)) != 0 || /* always display */
1789 	    (r = sshpkt_put_cstring(ssh, buf)) != 0 ||
1790 	    (r = sshpkt_put_cstring(ssh, "")) != 0 ||
1791 	    (r = sshpkt_send(ssh)) != 0 ||
1792 	    (r = ssh_packet_write_wait(ssh)) != 0)
1793 		fatal("%s: %s", __func__, ssh_err(r));
1794 }
1795 
1796 void
1797 sshpkt_fmt_connection_id(struct ssh *ssh, char *s, size_t l)
1798 {
1799 	snprintf(s, l, "%.200s%s%s port %d",
1800 	    ssh->log_preamble ? ssh->log_preamble : "",
1801 	    ssh->log_preamble ? " " : "",
1802 	    ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
1803 }
1804 
1805 /*
1806  * Pretty-print connection-terminating errors and exit.
1807  */
1808 void
1809 sshpkt_fatal(struct ssh *ssh, const char *tag, int r)
1810 {
1811 	char remote_id[512];
1812 
1813 	sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id));
1814 
1815 	switch (r) {
1816 	case SSH_ERR_CONN_CLOSED:
1817 		ssh_packet_clear_keys(ssh);
1818 		logdie("Connection closed by %s", remote_id);
1819 	case SSH_ERR_CONN_TIMEOUT:
1820 		ssh_packet_clear_keys(ssh);
1821 		logdie("Connection %s %s timed out",
1822 		    ssh->state->server_side ? "from" : "to", remote_id);
1823 	case SSH_ERR_DISCONNECTED:
1824 		ssh_packet_clear_keys(ssh);
1825 		logdie("Disconnected from %s", remote_id);
1826 	case SSH_ERR_SYSTEM_ERROR:
1827 		if (errno == ECONNRESET) {
1828 			ssh_packet_clear_keys(ssh);
1829 			logdie("Connection reset by %s", remote_id);
1830 		}
1831 		/* FALLTHROUGH */
1832 	case SSH_ERR_NO_CIPHER_ALG_MATCH:
1833 	case SSH_ERR_NO_MAC_ALG_MATCH:
1834 	case SSH_ERR_NO_COMPRESS_ALG_MATCH:
1835 	case SSH_ERR_NO_KEX_ALG_MATCH:
1836 	case SSH_ERR_NO_HOSTKEY_ALG_MATCH:
1837 		if (ssh && ssh->kex && ssh->kex->failed_choice) {
1838 			ssh_packet_clear_keys(ssh);
1839 			logdie("Unable to negotiate with %s: %s. "
1840 			    "Their offer: %s", remote_id, ssh_err(r),
1841 			    ssh->kex->failed_choice);
1842 		}
1843 		/* FALLTHROUGH */
1844 	default:
1845 		ssh_packet_clear_keys(ssh);
1846 		logdie("%s%sConnection %s %s: %s",
1847 		    tag != NULL ? tag : "", tag != NULL ? ": " : "",
1848 		    ssh->state->server_side ? "from" : "to",
1849 		    remote_id, ssh_err(r));
1850 	}
1851 }
1852 
1853 /*
1854  * Logs the error plus constructs and sends a disconnect packet, closes the
1855  * connection, and exits.  This function never returns. The error message
1856  * should not contain a newline.  The length of the formatted message must
1857  * not exceed 1024 bytes.
1858  */
1859 void
1860 ssh_packet_disconnect(struct ssh *ssh, const char *fmt,...)
1861 {
1862 	char buf[1024], remote_id[512];
1863 	va_list args;
1864 	static int disconnecting = 0;
1865 	int r;
1866 
1867 	if (disconnecting)	/* Guard against recursive invocations. */
1868 		fatal("packet_disconnect called recursively.");
1869 	disconnecting = 1;
1870 
1871 	/*
1872 	 * Format the message.  Note that the caller must make sure the
1873 	 * message is of limited size.
1874 	 */
1875 	sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id));
1876 	va_start(args, fmt);
1877 	vsnprintf(buf, sizeof(buf), fmt, args);
1878 	va_end(args);
1879 
1880 	/* Display the error locally */
1881 	logit("Disconnecting %s: %.100s", remote_id, buf);
1882 
1883 	/*
1884 	 * Send the disconnect message to the other side, and wait
1885 	 * for it to get sent.
1886 	 */
1887 	if ((r = sshpkt_disconnect(ssh, "%s", buf)) != 0)
1888 		sshpkt_fatal(ssh, __func__, r);
1889 
1890 	if ((r = ssh_packet_write_wait(ssh)) != 0)
1891 		sshpkt_fatal(ssh, __func__, r);
1892 
1893 	/* Close the connection. */
1894 	ssh_packet_close(ssh);
1895 	cleanup_exit(255);
1896 }
1897 
1898 /*
1899  * Checks if there is any buffered output, and tries to write some of
1900  * the output.
1901  */
1902 int
1903 ssh_packet_write_poll(struct ssh *ssh)
1904 {
1905 	struct session_state *state = ssh->state;
1906 	int len = sshbuf_len(state->output);
1907 	int r;
1908 
1909 	if (len > 0) {
1910 		len = write(state->connection_out,
1911 		    sshbuf_ptr(state->output), len);
1912 		if (len == -1) {
1913 			if (errno == EINTR || errno == EAGAIN ||
1914 			    errno == EWOULDBLOCK)
1915 				return 0;
1916 			return SSH_ERR_SYSTEM_ERROR;
1917 		}
1918 		if (len == 0)
1919 			return SSH_ERR_CONN_CLOSED;
1920 		if ((r = sshbuf_consume(state->output, len)) != 0)
1921 			return r;
1922 	}
1923 	return 0;
1924 }
1925 
1926 /*
1927  * Calls packet_write_poll repeatedly until all pending output data has been
1928  * written.
1929  */
1930 int
1931 ssh_packet_write_wait(struct ssh *ssh)
1932 {
1933 	fd_set *setp;
1934 	int ret, r, ms_remain = 0;
1935 	struct timeval start, timeout, *timeoutp = NULL;
1936 	struct session_state *state = ssh->state;
1937 
1938 	setp = calloc(howmany(state->connection_out + 1,
1939 	    NFDBITS), sizeof(fd_mask));
1940 	if (setp == NULL)
1941 		return SSH_ERR_ALLOC_FAIL;
1942 	if ((r = ssh_packet_write_poll(ssh)) != 0) {
1943 		free(setp);
1944 		return r;
1945 	}
1946 	while (ssh_packet_have_data_to_write(ssh)) {
1947 		memset(setp, 0, howmany(state->connection_out + 1,
1948 		    NFDBITS) * sizeof(fd_mask));
1949 		FD_SET(state->connection_out, setp);
1950 
1951 		if (state->packet_timeout_ms > 0) {
1952 			ms_remain = state->packet_timeout_ms;
1953 			timeoutp = &timeout;
1954 		}
1955 		for (;;) {
1956 			if (state->packet_timeout_ms != -1) {
1957 				ms_to_timeval(&timeout, ms_remain);
1958 				monotime_tv(&start);
1959 			}
1960 			if ((ret = select(state->connection_out + 1,
1961 			    NULL, setp, NULL, timeoutp)) >= 0)
1962 				break;
1963 			if (errno != EAGAIN && errno != EINTR &&
1964 			    errno != EWOULDBLOCK)
1965 				break;
1966 			if (state->packet_timeout_ms == -1)
1967 				continue;
1968 			ms_subtract_diff(&start, &ms_remain);
1969 			if (ms_remain <= 0) {
1970 				ret = 0;
1971 				break;
1972 			}
1973 		}
1974 		if (ret == 0) {
1975 			free(setp);
1976 			return SSH_ERR_CONN_TIMEOUT;
1977 		}
1978 		if ((r = ssh_packet_write_poll(ssh)) != 0) {
1979 			free(setp);
1980 			return r;
1981 		}
1982 	}
1983 	free(setp);
1984 	return 0;
1985 }
1986 
1987 /* Returns true if there is buffered data to write to the connection. */
1988 
1989 int
1990 ssh_packet_have_data_to_write(struct ssh *ssh)
1991 {
1992 	return sshbuf_len(ssh->state->output) != 0;
1993 }
1994 
1995 /* Returns true if there is not too much data to write to the connection. */
1996 
1997 int
1998 ssh_packet_not_very_much_data_to_write(struct ssh *ssh)
1999 {
2000 	if (ssh->state->interactive_mode)
2001 		return sshbuf_len(ssh->state->output) < 16384;
2002 	else
2003 		return sshbuf_len(ssh->state->output) < 128 * 1024;
2004 }
2005 
2006 void
2007 ssh_packet_set_tos(struct ssh *ssh, int tos)
2008 {
2009 #ifndef IP_TOS_IS_BROKEN
2010 	if (!ssh_packet_connection_is_on_socket(ssh) || tos == INT_MAX)
2011 		return;
2012 	switch (ssh_packet_connection_af(ssh)) {
2013 # ifdef IP_TOS
2014 	case AF_INET:
2015 		debug3("%s: set IP_TOS 0x%02x", __func__, tos);
2016 		if (setsockopt(ssh->state->connection_in,
2017 		    IPPROTO_IP, IP_TOS, &tos, sizeof(tos)) < 0)
2018 			error("setsockopt IP_TOS %d: %.100s:",
2019 			    tos, strerror(errno));
2020 		break;
2021 # endif /* IP_TOS */
2022 # ifdef IPV6_TCLASS
2023 	case AF_INET6:
2024 		debug3("%s: set IPV6_TCLASS 0x%02x", __func__, tos);
2025 		if (setsockopt(ssh->state->connection_in,
2026 		    IPPROTO_IPV6, IPV6_TCLASS, &tos, sizeof(tos)) < 0)
2027 			error("setsockopt IPV6_TCLASS %d: %.100s:",
2028 			    tos, strerror(errno));
2029 		break;
2030 # endif /* IPV6_TCLASS */
2031 	}
2032 #endif /* IP_TOS_IS_BROKEN */
2033 }
2034 
2035 /* Informs that the current session is interactive.  Sets IP flags for that. */
2036 
2037 void
2038 ssh_packet_set_interactive(struct ssh *ssh, int interactive, int qos_interactive, int qos_bulk)
2039 {
2040 	struct session_state *state = ssh->state;
2041 
2042 	if (state->set_interactive_called)
2043 		return;
2044 	state->set_interactive_called = 1;
2045 
2046 	/* Record that we are in interactive mode. */
2047 	state->interactive_mode = interactive;
2048 
2049 	/* Only set socket options if using a socket.  */
2050 	if (!ssh_packet_connection_is_on_socket(ssh))
2051 		return;
2052 	set_nodelay(state->connection_in);
2053 	ssh_packet_set_tos(ssh, interactive ? qos_interactive :
2054 	    qos_bulk);
2055 }
2056 
2057 /* Returns true if the current connection is interactive. */
2058 
2059 int
2060 ssh_packet_is_interactive(struct ssh *ssh)
2061 {
2062 	return ssh->state->interactive_mode;
2063 }
2064 
2065 int
2066 ssh_packet_set_maxsize(struct ssh *ssh, u_int s)
2067 {
2068 	struct session_state *state = ssh->state;
2069 
2070 	if (state->set_maxsize_called) {
2071 		logit("packet_set_maxsize: called twice: old %d new %d",
2072 		    state->max_packet_size, s);
2073 		return -1;
2074 	}
2075 	if (s < 4 * 1024 || s > 1024 * 1024) {
2076 		logit("packet_set_maxsize: bad size %d", s);
2077 		return -1;
2078 	}
2079 	state->set_maxsize_called = 1;
2080 	debug("packet_set_maxsize: setting to %d", s);
2081 	state->max_packet_size = s;
2082 	return s;
2083 }
2084 
2085 int
2086 ssh_packet_inc_alive_timeouts(struct ssh *ssh)
2087 {
2088 	return ++ssh->state->keep_alive_timeouts;
2089 }
2090 
2091 void
2092 ssh_packet_set_alive_timeouts(struct ssh *ssh, int ka)
2093 {
2094 	ssh->state->keep_alive_timeouts = ka;
2095 }
2096 
2097 u_int
2098 ssh_packet_get_maxsize(struct ssh *ssh)
2099 {
2100 	return ssh->state->max_packet_size;
2101 }
2102 
2103 void
2104 ssh_packet_set_rekey_limits(struct ssh *ssh, u_int64_t bytes, u_int32_t seconds)
2105 {
2106 	debug3("rekey after %llu bytes, %u seconds", (unsigned long long)bytes,
2107 	    (unsigned int)seconds);
2108 	ssh->state->rekey_limit = bytes;
2109 	ssh->state->rekey_interval = seconds;
2110 }
2111 
2112 time_t
2113 ssh_packet_get_rekey_timeout(struct ssh *ssh)
2114 {
2115 	time_t seconds;
2116 
2117 	seconds = ssh->state->rekey_time + ssh->state->rekey_interval -
2118 	    monotime();
2119 	return (seconds <= 0 ? 1 : seconds);
2120 }
2121 
2122 void
2123 ssh_packet_set_server(struct ssh *ssh)
2124 {
2125 	ssh->state->server_side = 1;
2126 }
2127 
2128 void
2129 ssh_packet_set_authenticated(struct ssh *ssh)
2130 {
2131 	ssh->state->after_authentication = 1;
2132 }
2133 
2134 void *
2135 ssh_packet_get_input(struct ssh *ssh)
2136 {
2137 	return (void *)ssh->state->input;
2138 }
2139 
2140 void *
2141 ssh_packet_get_output(struct ssh *ssh)
2142 {
2143 	return (void *)ssh->state->output;
2144 }
2145 
2146 /* Reset after_authentication and reset compression in post-auth privsep */
2147 static int
2148 ssh_packet_set_postauth(struct ssh *ssh)
2149 {
2150 	int r;
2151 
2152 	debug("%s: called", __func__);
2153 	/* This was set in net child, but is not visible in user child */
2154 	ssh->state->after_authentication = 1;
2155 	ssh->state->rekeying = 0;
2156 	if ((r = ssh_packet_enable_delayed_compress(ssh)) != 0)
2157 		return r;
2158 	return 0;
2159 }
2160 
2161 /* Packet state (de-)serialization for privsep */
2162 
2163 /* turn kex into a blob for packet state serialization */
2164 static int
2165 kex_to_blob(struct sshbuf *m, struct kex *kex)
2166 {
2167 	int r;
2168 
2169 	if ((r = sshbuf_put_string(m, kex->session_id,
2170 	    kex->session_id_len)) != 0 ||
2171 	    (r = sshbuf_put_u32(m, kex->we_need)) != 0 ||
2172 	    (r = sshbuf_put_cstring(m, kex->hostkey_alg)) != 0 ||
2173 	    (r = sshbuf_put_u32(m, kex->hostkey_type)) != 0 ||
2174 	    (r = sshbuf_put_u32(m, kex->hostkey_nid)) != 0 ||
2175 	    (r = sshbuf_put_u32(m, kex->kex_type)) != 0 ||
2176 	    (r = sshbuf_put_stringb(m, kex->my)) != 0 ||
2177 	    (r = sshbuf_put_stringb(m, kex->peer)) != 0 ||
2178 	    (r = sshbuf_put_u32(m, kex->flags)) != 0 ||
2179 	    (r = sshbuf_put_cstring(m, kex->client_version_string)) != 0 ||
2180 	    (r = sshbuf_put_cstring(m, kex->server_version_string)) != 0)
2181 		return r;
2182 	return 0;
2183 }
2184 
2185 /* turn key exchange results into a blob for packet state serialization */
2186 static int
2187 newkeys_to_blob(struct sshbuf *m, struct ssh *ssh, int mode)
2188 {
2189 	struct sshbuf *b;
2190 	struct sshcipher_ctx *cc;
2191 	struct sshcomp *comp;
2192 	struct sshenc *enc;
2193 	struct sshmac *mac;
2194 	struct newkeys *newkey;
2195 	int r;
2196 
2197 	if ((newkey = ssh->state->newkeys[mode]) == NULL)
2198 		return SSH_ERR_INTERNAL_ERROR;
2199 	enc = &newkey->enc;
2200 	mac = &newkey->mac;
2201 	comp = &newkey->comp;
2202 	cc = (mode == MODE_OUT) ? ssh->state->send_context :
2203 	    ssh->state->receive_context;
2204 	if ((r = cipher_get_keyiv(cc, enc->iv, enc->iv_len)) != 0)
2205 		return r;
2206 	if ((b = sshbuf_new()) == NULL)
2207 		return SSH_ERR_ALLOC_FAIL;
2208 	if ((r = sshbuf_put_cstring(b, enc->name)) != 0 ||
2209 	    (r = sshbuf_put_u32(b, enc->enabled)) != 0 ||
2210 	    (r = sshbuf_put_u32(b, enc->block_size)) != 0 ||
2211 	    (r = sshbuf_put_string(b, enc->key, enc->key_len)) != 0 ||
2212 	    (r = sshbuf_put_string(b, enc->iv, enc->iv_len)) != 0)
2213 		goto out;
2214 	if (cipher_authlen(enc->cipher) == 0) {
2215 		if ((r = sshbuf_put_cstring(b, mac->name)) != 0 ||
2216 		    (r = sshbuf_put_u32(b, mac->enabled)) != 0 ||
2217 		    (r = sshbuf_put_string(b, mac->key, mac->key_len)) != 0)
2218 			goto out;
2219 	}
2220 	if ((r = sshbuf_put_u32(b, comp->type)) != 0 ||
2221 	    (r = sshbuf_put_cstring(b, comp->name)) != 0)
2222 		goto out;
2223 	r = sshbuf_put_stringb(m, b);
2224  out:
2225 	sshbuf_free(b);
2226 	return r;
2227 }
2228 
2229 /* serialize packet state into a blob */
2230 int
2231 ssh_packet_get_state(struct ssh *ssh, struct sshbuf *m)
2232 {
2233 	struct session_state *state = ssh->state;
2234 	int r;
2235 
2236 	if ((r = kex_to_blob(m, ssh->kex)) != 0 ||
2237 	    (r = newkeys_to_blob(m, ssh, MODE_OUT)) != 0 ||
2238 	    (r = newkeys_to_blob(m, ssh, MODE_IN)) != 0 ||
2239 	    (r = sshbuf_put_u64(m, state->rekey_limit)) != 0 ||
2240 	    (r = sshbuf_put_u32(m, state->rekey_interval)) != 0 ||
2241 	    (r = sshbuf_put_u32(m, state->p_send.seqnr)) != 0 ||
2242 	    (r = sshbuf_put_u64(m, state->p_send.blocks)) != 0 ||
2243 	    (r = sshbuf_put_u32(m, state->p_send.packets)) != 0 ||
2244 	    (r = sshbuf_put_u64(m, state->p_send.bytes)) != 0 ||
2245 	    (r = sshbuf_put_u32(m, state->p_read.seqnr)) != 0 ||
2246 	    (r = sshbuf_put_u64(m, state->p_read.blocks)) != 0 ||
2247 	    (r = sshbuf_put_u32(m, state->p_read.packets)) != 0 ||
2248 	    (r = sshbuf_put_u64(m, state->p_read.bytes)) != 0 ||
2249 	    (r = sshbuf_put_stringb(m, state->input)) != 0 ||
2250 	    (r = sshbuf_put_stringb(m, state->output)) != 0)
2251 		return r;
2252 
2253 	return 0;
2254 }
2255 
2256 /* restore key exchange results from blob for packet state de-serialization */
2257 static int
2258 newkeys_from_blob(struct sshbuf *m, struct ssh *ssh, int mode)
2259 {
2260 	struct sshbuf *b = NULL;
2261 	struct sshcomp *comp;
2262 	struct sshenc *enc;
2263 	struct sshmac *mac;
2264 	struct newkeys *newkey = NULL;
2265 	size_t keylen, ivlen, maclen;
2266 	int r;
2267 
2268 	if ((newkey = calloc(1, sizeof(*newkey))) == NULL) {
2269 		r = SSH_ERR_ALLOC_FAIL;
2270 		goto out;
2271 	}
2272 	if ((r = sshbuf_froms(m, &b)) != 0)
2273 		goto out;
2274 #ifdef DEBUG_PK
2275 	sshbuf_dump(b, stderr);
2276 #endif
2277 	enc = &newkey->enc;
2278 	mac = &newkey->mac;
2279 	comp = &newkey->comp;
2280 
2281 	if ((r = sshbuf_get_cstring(b, &enc->name, NULL)) != 0 ||
2282 	    (r = sshbuf_get_u32(b, (u_int *)&enc->enabled)) != 0 ||
2283 	    (r = sshbuf_get_u32(b, &enc->block_size)) != 0 ||
2284 	    (r = sshbuf_get_string(b, &enc->key, &keylen)) != 0 ||
2285 	    (r = sshbuf_get_string(b, &enc->iv, &ivlen)) != 0)
2286 		goto out;
2287 	if ((enc->cipher = cipher_by_name(enc->name)) == NULL) {
2288 		r = SSH_ERR_INVALID_FORMAT;
2289 		goto out;
2290 	}
2291 	if (cipher_authlen(enc->cipher) == 0) {
2292 		if ((r = sshbuf_get_cstring(b, &mac->name, NULL)) != 0)
2293 			goto out;
2294 		if ((r = mac_setup(mac, mac->name)) != 0)
2295 			goto out;
2296 		if ((r = sshbuf_get_u32(b, (u_int *)&mac->enabled)) != 0 ||
2297 		    (r = sshbuf_get_string(b, &mac->key, &maclen)) != 0)
2298 			goto out;
2299 		if (maclen > mac->key_len) {
2300 			r = SSH_ERR_INVALID_FORMAT;
2301 			goto out;
2302 		}
2303 		mac->key_len = maclen;
2304 	}
2305 	if ((r = sshbuf_get_u32(b, &comp->type)) != 0 ||
2306 	    (r = sshbuf_get_cstring(b, &comp->name, NULL)) != 0)
2307 		goto out;
2308 	if (sshbuf_len(b) != 0) {
2309 		r = SSH_ERR_INVALID_FORMAT;
2310 		goto out;
2311 	}
2312 	enc->key_len = keylen;
2313 	enc->iv_len = ivlen;
2314 	ssh->kex->newkeys[mode] = newkey;
2315 	newkey = NULL;
2316 	r = 0;
2317  out:
2318 	free(newkey);
2319 	sshbuf_free(b);
2320 	return r;
2321 }
2322 
2323 /* restore kex from blob for packet state de-serialization */
2324 static int
2325 kex_from_blob(struct sshbuf *m, struct kex **kexp)
2326 {
2327 	struct kex *kex;
2328 	int r;
2329 
2330 	if ((kex = calloc(1, sizeof(struct kex))) == NULL ||
2331 	    (kex->my = sshbuf_new()) == NULL ||
2332 	    (kex->peer = sshbuf_new()) == NULL) {
2333 		r = SSH_ERR_ALLOC_FAIL;
2334 		goto out;
2335 	}
2336 	if ((r = sshbuf_get_string(m, &kex->session_id, &kex->session_id_len)) != 0 ||
2337 	    (r = sshbuf_get_u32(m, &kex->we_need)) != 0 ||
2338 	    (r = sshbuf_get_cstring(m, &kex->hostkey_alg, NULL)) != 0 ||
2339 	    (r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_type)) != 0 ||
2340 	    (r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_nid)) != 0 ||
2341 	    (r = sshbuf_get_u32(m, &kex->kex_type)) != 0 ||
2342 	    (r = sshbuf_get_stringb(m, kex->my)) != 0 ||
2343 	    (r = sshbuf_get_stringb(m, kex->peer)) != 0 ||
2344 	    (r = sshbuf_get_u32(m, &kex->flags)) != 0 ||
2345 	    (r = sshbuf_get_cstring(m, &kex->client_version_string, NULL)) != 0 ||
2346 	    (r = sshbuf_get_cstring(m, &kex->server_version_string, NULL)) != 0)
2347 		goto out;
2348 	kex->server = 1;
2349 	kex->done = 1;
2350 	r = 0;
2351  out:
2352 	if (r != 0 || kexp == NULL) {
2353 		if (kex != NULL) {
2354 			sshbuf_free(kex->my);
2355 			sshbuf_free(kex->peer);
2356 			free(kex);
2357 		}
2358 		if (kexp != NULL)
2359 			*kexp = NULL;
2360 	} else {
2361 		*kexp = kex;
2362 	}
2363 	return r;
2364 }
2365 
2366 /*
2367  * Restore packet state from content of blob 'm' (de-serialization).
2368  * Note that 'm' will be partially consumed on parsing or any other errors.
2369  */
2370 int
2371 ssh_packet_set_state(struct ssh *ssh, struct sshbuf *m)
2372 {
2373 	struct session_state *state = ssh->state;
2374 	const u_char *input, *output;
2375 	size_t ilen, olen;
2376 	int r;
2377 
2378 	if ((r = kex_from_blob(m, &ssh->kex)) != 0 ||
2379 	    (r = newkeys_from_blob(m, ssh, MODE_OUT)) != 0 ||
2380 	    (r = newkeys_from_blob(m, ssh, MODE_IN)) != 0 ||
2381 	    (r = sshbuf_get_u64(m, &state->rekey_limit)) != 0 ||
2382 	    (r = sshbuf_get_u32(m, &state->rekey_interval)) != 0 ||
2383 	    (r = sshbuf_get_u32(m, &state->p_send.seqnr)) != 0 ||
2384 	    (r = sshbuf_get_u64(m, &state->p_send.blocks)) != 0 ||
2385 	    (r = sshbuf_get_u32(m, &state->p_send.packets)) != 0 ||
2386 	    (r = sshbuf_get_u64(m, &state->p_send.bytes)) != 0 ||
2387 	    (r = sshbuf_get_u32(m, &state->p_read.seqnr)) != 0 ||
2388 	    (r = sshbuf_get_u64(m, &state->p_read.blocks)) != 0 ||
2389 	    (r = sshbuf_get_u32(m, &state->p_read.packets)) != 0 ||
2390 	    (r = sshbuf_get_u64(m, &state->p_read.bytes)) != 0)
2391 		return r;
2392 	/*
2393 	 * We set the time here so that in post-auth privsep slave we
2394 	 * count from the completion of the authentication.
2395 	 */
2396 	state->rekey_time = monotime();
2397 	/* XXX ssh_set_newkeys overrides p_read.packets? XXX */
2398 	if ((r = ssh_set_newkeys(ssh, MODE_IN)) != 0 ||
2399 	    (r = ssh_set_newkeys(ssh, MODE_OUT)) != 0)
2400 		return r;
2401 
2402 	if ((r = ssh_packet_set_postauth(ssh)) != 0)
2403 		return r;
2404 
2405 	sshbuf_reset(state->input);
2406 	sshbuf_reset(state->output);
2407 	if ((r = sshbuf_get_string_direct(m, &input, &ilen)) != 0 ||
2408 	    (r = sshbuf_get_string_direct(m, &output, &olen)) != 0 ||
2409 	    (r = sshbuf_put(state->input, input, ilen)) != 0 ||
2410 	    (r = sshbuf_put(state->output, output, olen)) != 0)
2411 		return r;
2412 
2413 	if (sshbuf_len(m))
2414 		return SSH_ERR_INVALID_FORMAT;
2415 	debug3("%s: done", __func__);
2416 	return 0;
2417 }
2418 
2419 /* NEW API */
2420 
2421 /* put data to the outgoing packet */
2422 
2423 int
2424 sshpkt_put(struct ssh *ssh, const void *v, size_t len)
2425 {
2426 	return sshbuf_put(ssh->state->outgoing_packet, v, len);
2427 }
2428 
2429 int
2430 sshpkt_putb(struct ssh *ssh, const struct sshbuf *b)
2431 {
2432 	return sshbuf_putb(ssh->state->outgoing_packet, b);
2433 }
2434 
2435 int
2436 sshpkt_put_u8(struct ssh *ssh, u_char val)
2437 {
2438 	return sshbuf_put_u8(ssh->state->outgoing_packet, val);
2439 }
2440 
2441 int
2442 sshpkt_put_u32(struct ssh *ssh, u_int32_t val)
2443 {
2444 	return sshbuf_put_u32(ssh->state->outgoing_packet, val);
2445 }
2446 
2447 int
2448 sshpkt_put_u64(struct ssh *ssh, u_int64_t val)
2449 {
2450 	return sshbuf_put_u64(ssh->state->outgoing_packet, val);
2451 }
2452 
2453 int
2454 sshpkt_put_string(struct ssh *ssh, const void *v, size_t len)
2455 {
2456 	return sshbuf_put_string(ssh->state->outgoing_packet, v, len);
2457 }
2458 
2459 int
2460 sshpkt_put_cstring(struct ssh *ssh, const void *v)
2461 {
2462 	return sshbuf_put_cstring(ssh->state->outgoing_packet, v);
2463 }
2464 
2465 int
2466 sshpkt_put_stringb(struct ssh *ssh, const struct sshbuf *v)
2467 {
2468 	return sshbuf_put_stringb(ssh->state->outgoing_packet, v);
2469 }
2470 
2471 #ifdef WITH_OPENSSL
2472 #ifdef OPENSSL_HAS_ECC
2473 int
2474 sshpkt_put_ec(struct ssh *ssh, const EC_POINT *v, const EC_GROUP *g)
2475 {
2476 	return sshbuf_put_ec(ssh->state->outgoing_packet, v, g);
2477 }
2478 #endif /* OPENSSL_HAS_ECC */
2479 
2480 
2481 int
2482 sshpkt_put_bignum2(struct ssh *ssh, const BIGNUM *v)
2483 {
2484 	return sshbuf_put_bignum2(ssh->state->outgoing_packet, v);
2485 }
2486 #endif /* WITH_OPENSSL */
2487 
2488 /* fetch data from the incoming packet */
2489 
2490 int
2491 sshpkt_get(struct ssh *ssh, void *valp, size_t len)
2492 {
2493 	return sshbuf_get(ssh->state->incoming_packet, valp, len);
2494 }
2495 
2496 int
2497 sshpkt_get_u8(struct ssh *ssh, u_char *valp)
2498 {
2499 	return sshbuf_get_u8(ssh->state->incoming_packet, valp);
2500 }
2501 
2502 int
2503 sshpkt_get_u32(struct ssh *ssh, u_int32_t *valp)
2504 {
2505 	return sshbuf_get_u32(ssh->state->incoming_packet, valp);
2506 }
2507 
2508 int
2509 sshpkt_get_u64(struct ssh *ssh, u_int64_t *valp)
2510 {
2511 	return sshbuf_get_u64(ssh->state->incoming_packet, valp);
2512 }
2513 
2514 int
2515 sshpkt_get_string(struct ssh *ssh, u_char **valp, size_t *lenp)
2516 {
2517 	return sshbuf_get_string(ssh->state->incoming_packet, valp, lenp);
2518 }
2519 
2520 int
2521 sshpkt_get_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp)
2522 {
2523 	return sshbuf_get_string_direct(ssh->state->incoming_packet, valp, lenp);
2524 }
2525 
2526 int
2527 sshpkt_peek_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp)
2528 {
2529 	return sshbuf_peek_string_direct(ssh->state->incoming_packet, valp, lenp);
2530 }
2531 
2532 int
2533 sshpkt_get_cstring(struct ssh *ssh, char **valp, size_t *lenp)
2534 {
2535 	return sshbuf_get_cstring(ssh->state->incoming_packet, valp, lenp);
2536 }
2537 
2538 #ifdef WITH_OPENSSL
2539 #ifdef OPENSSL_HAS_ECC
2540 int
2541 sshpkt_get_ec(struct ssh *ssh, EC_POINT *v, const EC_GROUP *g)
2542 {
2543 	return sshbuf_get_ec(ssh->state->incoming_packet, v, g);
2544 }
2545 #endif /* OPENSSL_HAS_ECC */
2546 
2547 
2548 int
2549 sshpkt_get_bignum2(struct ssh *ssh, BIGNUM *v)
2550 {
2551 	return sshbuf_get_bignum2(ssh->state->incoming_packet, v);
2552 }
2553 #endif /* WITH_OPENSSL */
2554 
2555 int
2556 sshpkt_get_end(struct ssh *ssh)
2557 {
2558 	if (sshbuf_len(ssh->state->incoming_packet) > 0)
2559 		return SSH_ERR_UNEXPECTED_TRAILING_DATA;
2560 	return 0;
2561 }
2562 
2563 const u_char *
2564 sshpkt_ptr(struct ssh *ssh, size_t *lenp)
2565 {
2566 	if (lenp != NULL)
2567 		*lenp = sshbuf_len(ssh->state->incoming_packet);
2568 	return sshbuf_ptr(ssh->state->incoming_packet);
2569 }
2570 
2571 /* start a new packet */
2572 
2573 int
2574 sshpkt_start(struct ssh *ssh, u_char type)
2575 {
2576 	u_char buf[6]; /* u32 packet length, u8 pad len, u8 type */
2577 
2578 	DBG(debug("packet_start[%d]", type));
2579 	memset(buf, 0, sizeof(buf));
2580 	buf[sizeof(buf) - 1] = type;
2581 	sshbuf_reset(ssh->state->outgoing_packet);
2582 	return sshbuf_put(ssh->state->outgoing_packet, buf, sizeof(buf));
2583 }
2584 
2585 static int
2586 ssh_packet_send_mux(struct ssh *ssh)
2587 {
2588 	struct session_state *state = ssh->state;
2589 	u_char type, *cp;
2590 	size_t len;
2591 	int r;
2592 
2593 	if (ssh->kex)
2594 		return SSH_ERR_INTERNAL_ERROR;
2595 	len = sshbuf_len(state->outgoing_packet);
2596 	if (len < 6)
2597 		return SSH_ERR_INTERNAL_ERROR;
2598 	cp = sshbuf_mutable_ptr(state->outgoing_packet);
2599 	type = cp[5];
2600 	if (ssh_packet_log_type(type))
2601 		debug3("%s: type %u", __func__, type);
2602 	/* drop everything, but the connection protocol */
2603 	if (type >= SSH2_MSG_CONNECTION_MIN &&
2604 	    type <= SSH2_MSG_CONNECTION_MAX) {
2605 		POKE_U32(cp, len - 4);
2606 		if ((r = sshbuf_putb(state->output,
2607 		    state->outgoing_packet)) != 0)
2608 			return r;
2609 		/* sshbuf_dump(state->output, stderr); */
2610 	}
2611 	sshbuf_reset(state->outgoing_packet);
2612 	return 0;
2613 }
2614 
2615 /*
2616  * 9.2.  Ignored Data Message
2617  *
2618  *   byte      SSH_MSG_IGNORE
2619  *   string    data
2620  *
2621  * All implementations MUST understand (and ignore) this message at any
2622  * time (after receiving the protocol version). No implementation is
2623  * required to send them. This message can be used as an additional
2624  * protection measure against advanced traffic analysis techniques.
2625  */
2626 int
2627 sshpkt_msg_ignore(struct ssh *ssh, u_int nbytes)
2628 {
2629 	u_int32_t rnd = 0;
2630 	int r;
2631 	u_int i;
2632 
2633 	if ((r = sshpkt_start(ssh, SSH2_MSG_IGNORE)) != 0 ||
2634 	    (r = sshpkt_put_u32(ssh, nbytes)) != 0)
2635 		return r;
2636 	for (i = 0; i < nbytes; i++) {
2637 		if (i % 4 == 0)
2638 			rnd = arc4random();
2639 		if ((r = sshpkt_put_u8(ssh, (u_char)rnd & 0xff)) != 0)
2640 			return r;
2641 		rnd >>= 8;
2642 	}
2643 	return 0;
2644 }
2645 
2646 /* send it */
2647 
2648 int
2649 sshpkt_send(struct ssh *ssh)
2650 {
2651 	if (ssh->state && ssh->state->mux)
2652 		return ssh_packet_send_mux(ssh);
2653 	return ssh_packet_send2(ssh);
2654 }
2655 
2656 int
2657 sshpkt_disconnect(struct ssh *ssh, const char *fmt,...)
2658 {
2659 	char buf[1024];
2660 	va_list args;
2661 	int r;
2662 
2663 	va_start(args, fmt);
2664 	vsnprintf(buf, sizeof(buf), fmt, args);
2665 	va_end(args);
2666 
2667 	if ((r = sshpkt_start(ssh, SSH2_MSG_DISCONNECT)) != 0 ||
2668 	    (r = sshpkt_put_u32(ssh, SSH2_DISCONNECT_PROTOCOL_ERROR)) != 0 ||
2669 	    (r = sshpkt_put_cstring(ssh, buf)) != 0 ||
2670 	    (r = sshpkt_put_cstring(ssh, "")) != 0 ||
2671 	    (r = sshpkt_send(ssh)) != 0)
2672 		return r;
2673 	return 0;
2674 }
2675 
2676 /* roundup current message to pad bytes */
2677 int
2678 sshpkt_add_padding(struct ssh *ssh, u_char pad)
2679 {
2680 	ssh->state->extra_pad = pad;
2681 	return 0;
2682 }
2683