1 /* $OpenBSD: packet.c,v 1.291 2020/03/06 18:20:44 markus Exp $ */
2 /*
3 * Author: Tatu Ylonen <ylo@cs.hut.fi>
4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * All rights reserved
6 * This file contains code implementing the packet protocol and communication
7 * with the other side. This same code is used both on client and server side.
8 *
9 * As far as I am concerned, the code I have written for this software
10 * can be used freely for any purpose. Any derived versions of this
11 * software must be clearly marked as such, and if the derived work is
12 * incompatible with the protocol description in the RFC file, it must be
13 * called by a name other than "ssh" or "Secure Shell".
14 *
15 *
16 * SSH2 packet format added by Markus Friedl.
17 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
18 *
19 * Redistribution and use in source and binary forms, with or without
20 * modification, are permitted provided that the following conditions
21 * are met:
22 * 1. Redistributions of source code must retain the above copyright
23 * notice, this list of conditions and the following disclaimer.
24 * 2. Redistributions in binary form must reproduce the above copyright
25 * notice, this list of conditions and the following disclaimer in the
26 * documentation and/or other materials provided with the distribution.
27 *
28 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
29 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
30 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
31 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
32 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
33 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
34 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
35 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
36 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
37 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
38 */
39
40 #include "includes.h"
41
42 #include <sys/types.h>
43 #include "openbsd-compat/sys-queue.h"
44 #include <sys/socket.h>
45 #ifdef HAVE_SYS_TIME_H
46 # include <sys/time.h>
47 #endif
48
49 #include <netinet/in.h>
50 #include <netinet/ip.h>
51 #include <arpa/inet.h>
52
53 #include <errno.h>
54 #include <netdb.h>
55 #include <stdarg.h>
56 #include <stdio.h>
57 #include <stdlib.h>
58 #include <string.h>
59 #include <unistd.h>
60 #include <limits.h>
61 #ifdef HAVE_POLL_H
62 #include <poll.h>
63 #endif
64 #include <signal.h>
65 #include <time.h>
66
67 /*
68 * Explicitly include OpenSSL before zlib as some versions of OpenSSL have
69 * "free_func" in their headers, which zlib typedefs.
70 */
71 #ifdef WITH_OPENSSL
72 # include <openssl/bn.h>
73 # include <openssl/evp.h>
74 # ifdef OPENSSL_HAS_ECC
75 # include <openssl/ec.h>
76 # endif
77 #endif
78
79 #ifdef WITH_ZLIB
80 #include <zlib.h>
81 #endif
82
83 #include "xmalloc.h"
84 #include "compat.h"
85 #include "ssh2.h"
86 #include "cipher.h"
87 #include "sshkey.h"
88 #include "kex.h"
89 #include "digest.h"
90 #include "mac.h"
91 #include "log.h"
92 #include "canohost.h"
93 #include "misc.h"
94 #include "channels.h"
95 #include "ssh.h"
96 #include "packet.h"
97 #include "ssherr.h"
98 #include "sshbuf.h"
99
100 #ifdef PACKET_DEBUG
101 #define DBG(x) x
102 #else
103 #define DBG(x)
104 #endif
105
106 #define PACKET_MAX_SIZE (256 * 1024)
107
108 struct packet_state {
109 u_int32_t seqnr;
110 u_int32_t packets;
111 u_int64_t blocks;
112 u_int64_t bytes;
113 };
114
115 struct packet {
116 TAILQ_ENTRY(packet) next;
117 u_char type;
118 struct sshbuf *payload;
119 };
120
121 struct session_state {
122 /*
123 * This variable contains the file descriptors used for
124 * communicating with the other side. connection_in is used for
125 * reading; connection_out for writing. These can be the same
126 * descriptor, in which case it is assumed to be a socket.
127 */
128 int connection_in;
129 int connection_out;
130
131 /* Protocol flags for the remote side. */
132 u_int remote_protocol_flags;
133
134 /* Encryption context for receiving data. Only used for decryption. */
135 struct sshcipher_ctx *receive_context;
136
137 /* Encryption context for sending data. Only used for encryption. */
138 struct sshcipher_ctx *send_context;
139
140 /* Buffer for raw input data from the socket. */
141 struct sshbuf *input;
142
143 /* Buffer for raw output data going to the socket. */
144 struct sshbuf *output;
145
146 /* Buffer for the partial outgoing packet being constructed. */
147 struct sshbuf *outgoing_packet;
148
149 /* Buffer for the incoming packet currently being processed. */
150 struct sshbuf *incoming_packet;
151
152 /* Scratch buffer for packet compression/decompression. */
153 struct sshbuf *compression_buffer;
154
155 #ifdef WITH_ZLIB
156 /* Incoming/outgoing compression dictionaries */
157 z_stream compression_in_stream;
158 z_stream compression_out_stream;
159 #endif
160 int compression_in_started;
161 int compression_out_started;
162 int compression_in_failures;
163 int compression_out_failures;
164
165 /* default maximum packet size */
166 u_int max_packet_size;
167
168 /* Flag indicating whether this module has been initialized. */
169 int initialized;
170
171 /* Set to true if the connection is interactive. */
172 int interactive_mode;
173
174 /* Set to true if we are the server side. */
175 int server_side;
176
177 /* Set to true if we are authenticated. */
178 int after_authentication;
179
180 int keep_alive_timeouts;
181
182 /* The maximum time that we will wait to send or receive a packet */
183 int packet_timeout_ms;
184
185 /* Session key information for Encryption and MAC */
186 struct newkeys *newkeys[MODE_MAX];
187 struct packet_state p_read, p_send;
188
189 /* Volume-based rekeying */
190 u_int64_t max_blocks_in, max_blocks_out, rekey_limit;
191
192 /* Time-based rekeying */
193 u_int32_t rekey_interval; /* how often in seconds */
194 time_t rekey_time; /* time of last rekeying */
195
196 /* roundup current message to extra_pad bytes */
197 u_char extra_pad;
198
199 /* XXX discard incoming data after MAC error */
200 u_int packet_discard;
201 size_t packet_discard_mac_already;
202 struct sshmac *packet_discard_mac;
203
204 /* Used in packet_read_poll2() */
205 u_int packlen;
206
207 /* Used in packet_send2 */
208 int rekeying;
209
210 /* Used in ssh_packet_send_mux() */
211 int mux;
212
213 /* Used in packet_set_interactive */
214 int set_interactive_called;
215
216 /* Used in packet_set_maxsize */
217 int set_maxsize_called;
218
219 /* One-off warning about weak ciphers */
220 int cipher_warning_done;
221
222 /* Hook for fuzzing inbound packets */
223 ssh_packet_hook_fn *hook_in;
224 void *hook_in_ctx;
225
226 TAILQ_HEAD(, packet) outgoing;
227 };
228
229 struct ssh *
ssh_alloc_session_state(void)230 ssh_alloc_session_state(void)
231 {
232 struct ssh *ssh = NULL;
233 struct session_state *state = NULL;
234
235 if ((ssh = calloc(1, sizeof(*ssh))) == NULL ||
236 (state = calloc(1, sizeof(*state))) == NULL ||
237 (ssh->kex = kex_new()) == NULL ||
238 (state->input = sshbuf_new()) == NULL ||
239 (state->output = sshbuf_new()) == NULL ||
240 (state->outgoing_packet = sshbuf_new()) == NULL ||
241 (state->incoming_packet = sshbuf_new()) == NULL)
242 goto fail;
243 TAILQ_INIT(&state->outgoing);
244 TAILQ_INIT(&ssh->private_keys);
245 TAILQ_INIT(&ssh->public_keys);
246 state->connection_in = -1;
247 state->connection_out = -1;
248 state->max_packet_size = 32768;
249 state->packet_timeout_ms = -1;
250 state->p_send.packets = state->p_read.packets = 0;
251 state->initialized = 1;
252 /*
253 * ssh_packet_send2() needs to queue packets until
254 * we've done the initial key exchange.
255 */
256 state->rekeying = 1;
257 ssh->state = state;
258 return ssh;
259 fail:
260 if (ssh) {
261 kex_free(ssh->kex);
262 free(ssh);
263 }
264 if (state) {
265 sshbuf_free(state->input);
266 sshbuf_free(state->output);
267 sshbuf_free(state->incoming_packet);
268 sshbuf_free(state->outgoing_packet);
269 free(state);
270 }
271 return NULL;
272 }
273
274 void
ssh_packet_set_input_hook(struct ssh * ssh,ssh_packet_hook_fn * hook,void * ctx)275 ssh_packet_set_input_hook(struct ssh *ssh, ssh_packet_hook_fn *hook, void *ctx)
276 {
277 ssh->state->hook_in = hook;
278 ssh->state->hook_in_ctx = ctx;
279 }
280
281 /* Returns nonzero if rekeying is in progress */
282 int
ssh_packet_is_rekeying(struct ssh * ssh)283 ssh_packet_is_rekeying(struct ssh *ssh)
284 {
285 return ssh->state->rekeying || ssh->kex->done == 0;
286 }
287
288 /*
289 * Sets the descriptors used for communication.
290 */
291 struct ssh *
ssh_packet_set_connection(struct ssh * ssh,int fd_in,int fd_out)292 ssh_packet_set_connection(struct ssh *ssh, int fd_in, int fd_out)
293 {
294 struct session_state *state;
295 const struct sshcipher *none = cipher_by_name("none");
296 int r;
297
298 if (none == NULL) {
299 error("%s: cannot load cipher 'none'", __func__);
300 return NULL;
301 }
302 if (ssh == NULL)
303 ssh = ssh_alloc_session_state();
304 if (ssh == NULL) {
305 error("%s: could not allocate state", __func__);
306 return NULL;
307 }
308 state = ssh->state;
309 state->connection_in = fd_in;
310 state->connection_out = fd_out;
311 if ((r = cipher_init(&state->send_context, none,
312 (const u_char *)"", 0, NULL, 0, CIPHER_ENCRYPT)) != 0 ||
313 (r = cipher_init(&state->receive_context, none,
314 (const u_char *)"", 0, NULL, 0, CIPHER_DECRYPT)) != 0) {
315 error("%s: cipher_init failed: %s", __func__, ssh_err(r));
316 free(ssh); /* XXX need ssh_free_session_state? */
317 return NULL;
318 }
319 state->newkeys[MODE_IN] = state->newkeys[MODE_OUT] = NULL;
320 /*
321 * Cache the IP address of the remote connection for use in error
322 * messages that might be generated after the connection has closed.
323 */
324 (void)ssh_remote_ipaddr(ssh);
325 return ssh;
326 }
327
328 void
ssh_packet_set_timeout(struct ssh * ssh,int timeout,int count)329 ssh_packet_set_timeout(struct ssh *ssh, int timeout, int count)
330 {
331 struct session_state *state = ssh->state;
332
333 if (timeout <= 0 || count <= 0) {
334 state->packet_timeout_ms = -1;
335 return;
336 }
337 if ((INT_MAX / 1000) / count < timeout)
338 state->packet_timeout_ms = INT_MAX;
339 else
340 state->packet_timeout_ms = timeout * count * 1000;
341 }
342
343 void
ssh_packet_set_mux(struct ssh * ssh)344 ssh_packet_set_mux(struct ssh *ssh)
345 {
346 ssh->state->mux = 1;
347 ssh->state->rekeying = 0;
348 }
349
350 int
ssh_packet_get_mux(struct ssh * ssh)351 ssh_packet_get_mux(struct ssh *ssh)
352 {
353 return ssh->state->mux;
354 }
355
356 int
ssh_packet_set_log_preamble(struct ssh * ssh,const char * fmt,...)357 ssh_packet_set_log_preamble(struct ssh *ssh, const char *fmt, ...)
358 {
359 va_list args;
360 int r;
361
362 free(ssh->log_preamble);
363 if (fmt == NULL)
364 ssh->log_preamble = NULL;
365 else {
366 va_start(args, fmt);
367 r = vasprintf(&ssh->log_preamble, fmt, args);
368 va_end(args);
369 if (r < 0 || ssh->log_preamble == NULL)
370 return SSH_ERR_ALLOC_FAIL;
371 }
372 return 0;
373 }
374
375 int
ssh_packet_stop_discard(struct ssh * ssh)376 ssh_packet_stop_discard(struct ssh *ssh)
377 {
378 struct session_state *state = ssh->state;
379 int r;
380
381 if (state->packet_discard_mac) {
382 char buf[1024];
383 size_t dlen = PACKET_MAX_SIZE;
384
385 if (dlen > state->packet_discard_mac_already)
386 dlen -= state->packet_discard_mac_already;
387 memset(buf, 'a', sizeof(buf));
388 while (sshbuf_len(state->incoming_packet) < dlen)
389 if ((r = sshbuf_put(state->incoming_packet, buf,
390 sizeof(buf))) != 0)
391 return r;
392 (void) mac_compute(state->packet_discard_mac,
393 state->p_read.seqnr,
394 sshbuf_ptr(state->incoming_packet), dlen,
395 NULL, 0);
396 }
397 logit("Finished discarding for %.200s port %d",
398 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
399 return SSH_ERR_MAC_INVALID;
400 }
401
402 static int
ssh_packet_start_discard(struct ssh * ssh,struct sshenc * enc,struct sshmac * mac,size_t mac_already,u_int discard)403 ssh_packet_start_discard(struct ssh *ssh, struct sshenc *enc,
404 struct sshmac *mac, size_t mac_already, u_int discard)
405 {
406 struct session_state *state = ssh->state;
407 int r;
408
409 if (enc == NULL || !cipher_is_cbc(enc->cipher) || (mac && mac->etm)) {
410 if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0)
411 return r;
412 return SSH_ERR_MAC_INVALID;
413 }
414 /*
415 * Record number of bytes over which the mac has already
416 * been computed in order to minimize timing attacks.
417 */
418 if (mac && mac->enabled) {
419 state->packet_discard_mac = mac;
420 state->packet_discard_mac_already = mac_already;
421 }
422 if (sshbuf_len(state->input) >= discard)
423 return ssh_packet_stop_discard(ssh);
424 state->packet_discard = discard - sshbuf_len(state->input);
425 return 0;
426 }
427
428 /* Returns 1 if remote host is connected via socket, 0 if not. */
429
430 int
ssh_packet_connection_is_on_socket(struct ssh * ssh)431 ssh_packet_connection_is_on_socket(struct ssh *ssh)
432 {
433 struct session_state *state;
434 struct sockaddr_storage from, to;
435 socklen_t fromlen, tolen;
436
437 if (ssh == NULL || ssh->state == NULL)
438 return 0;
439
440 state = ssh->state;
441 if (state->connection_in == -1 || state->connection_out == -1)
442 return 0;
443 /* filedescriptors in and out are the same, so it's a socket */
444 if (state->connection_in == state->connection_out)
445 return 1;
446 fromlen = sizeof(from);
447 memset(&from, 0, sizeof(from));
448 if (getpeername(state->connection_in, (struct sockaddr *)&from,
449 &fromlen) == -1)
450 return 0;
451 tolen = sizeof(to);
452 memset(&to, 0, sizeof(to));
453 if (getpeername(state->connection_out, (struct sockaddr *)&to,
454 &tolen) == -1)
455 return 0;
456 if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0)
457 return 0;
458 if (from.ss_family != AF_INET && from.ss_family != AF_INET6)
459 return 0;
460 return 1;
461 }
462
463 void
ssh_packet_get_bytes(struct ssh * ssh,u_int64_t * ibytes,u_int64_t * obytes)464 ssh_packet_get_bytes(struct ssh *ssh, u_int64_t *ibytes, u_int64_t *obytes)
465 {
466 if (ibytes)
467 *ibytes = ssh->state->p_read.bytes;
468 if (obytes)
469 *obytes = ssh->state->p_send.bytes;
470 }
471
472 int
ssh_packet_connection_af(struct ssh * ssh)473 ssh_packet_connection_af(struct ssh *ssh)
474 {
475 struct sockaddr_storage to;
476 socklen_t tolen = sizeof(to);
477
478 memset(&to, 0, sizeof(to));
479 if (getsockname(ssh->state->connection_out, (struct sockaddr *)&to,
480 &tolen) == -1)
481 return 0;
482 #ifdef IPV4_IN_IPV6
483 if (to.ss_family == AF_INET6 &&
484 IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)&to)->sin6_addr))
485 return AF_INET;
486 #endif
487 return to.ss_family;
488 }
489
490 /* Sets the connection into non-blocking mode. */
491
492 void
ssh_packet_set_nonblocking(struct ssh * ssh)493 ssh_packet_set_nonblocking(struct ssh *ssh)
494 {
495 /* Set the socket into non-blocking mode. */
496 set_nonblock(ssh->state->connection_in);
497
498 if (ssh->state->connection_out != ssh->state->connection_in)
499 set_nonblock(ssh->state->connection_out);
500 }
501
502 /* Returns the socket used for reading. */
503
504 int
ssh_packet_get_connection_in(struct ssh * ssh)505 ssh_packet_get_connection_in(struct ssh *ssh)
506 {
507 return ssh->state->connection_in;
508 }
509
510 /* Returns the descriptor used for writing. */
511
512 int
ssh_packet_get_connection_out(struct ssh * ssh)513 ssh_packet_get_connection_out(struct ssh *ssh)
514 {
515 return ssh->state->connection_out;
516 }
517
518 /*
519 * Returns the IP-address of the remote host as a string. The returned
520 * string must not be freed.
521 */
522
523 const char *
ssh_remote_ipaddr(struct ssh * ssh)524 ssh_remote_ipaddr(struct ssh *ssh)
525 {
526 int sock;
527
528 /* Check whether we have cached the ipaddr. */
529 if (ssh->remote_ipaddr == NULL) {
530 if (ssh_packet_connection_is_on_socket(ssh)) {
531 sock = ssh->state->connection_in;
532 ssh->remote_ipaddr = get_peer_ipaddr(sock);
533 ssh->remote_port = get_peer_port(sock);
534 ssh->local_ipaddr = get_local_ipaddr(sock);
535 ssh->local_port = get_local_port(sock);
536 } else {
537 ssh->remote_ipaddr = xstrdup("UNKNOWN");
538 ssh->remote_port = 65535;
539 ssh->local_ipaddr = xstrdup("UNKNOWN");
540 ssh->local_port = 65535;
541 }
542 }
543 return ssh->remote_ipaddr;
544 }
545
546 /* Returns the port number of the remote host. */
547
548 int
ssh_remote_port(struct ssh * ssh)549 ssh_remote_port(struct ssh *ssh)
550 {
551 (void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */
552 return ssh->remote_port;
553 }
554
555 /*
556 * Returns the IP-address of the local host as a string. The returned
557 * string must not be freed.
558 */
559
560 const char *
ssh_local_ipaddr(struct ssh * ssh)561 ssh_local_ipaddr(struct ssh *ssh)
562 {
563 (void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */
564 return ssh->local_ipaddr;
565 }
566
567 /* Returns the port number of the local host. */
568
569 int
ssh_local_port(struct ssh * ssh)570 ssh_local_port(struct ssh *ssh)
571 {
572 (void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */
573 return ssh->local_port;
574 }
575
576 /* Returns the routing domain of the input socket, or NULL if unavailable */
577 const char *
ssh_packet_rdomain_in(struct ssh * ssh)578 ssh_packet_rdomain_in(struct ssh *ssh)
579 {
580 if (ssh->rdomain_in != NULL)
581 return ssh->rdomain_in;
582 if (!ssh_packet_connection_is_on_socket(ssh))
583 return NULL;
584 ssh->rdomain_in = get_rdomain(ssh->state->connection_in);
585 return ssh->rdomain_in;
586 }
587
588 /* Closes the connection and clears and frees internal data structures. */
589
590 static void
ssh_packet_close_internal(struct ssh * ssh,int do_close)591 ssh_packet_close_internal(struct ssh *ssh, int do_close)
592 {
593 struct session_state *state = ssh->state;
594 u_int mode;
595
596 if (!state->initialized)
597 return;
598 state->initialized = 0;
599 if (do_close) {
600 if (state->connection_in == state->connection_out) {
601 close(state->connection_out);
602 } else {
603 close(state->connection_in);
604 close(state->connection_out);
605 }
606 }
607 sshbuf_free(state->input);
608 sshbuf_free(state->output);
609 sshbuf_free(state->outgoing_packet);
610 sshbuf_free(state->incoming_packet);
611 for (mode = 0; mode < MODE_MAX; mode++) {
612 kex_free_newkeys(state->newkeys[mode]); /* current keys */
613 state->newkeys[mode] = NULL;
614 ssh_clear_newkeys(ssh, mode); /* next keys */
615 }
616 #ifdef WITH_ZLIB
617 /* compression state is in shared mem, so we can only release it once */
618 if (do_close && state->compression_buffer) {
619 sshbuf_free(state->compression_buffer);
620 if (state->compression_out_started) {
621 z_streamp stream = &state->compression_out_stream;
622 debug("compress outgoing: "
623 "raw data %llu, compressed %llu, factor %.2f",
624 (unsigned long long)stream->total_in,
625 (unsigned long long)stream->total_out,
626 stream->total_in == 0 ? 0.0 :
627 (double) stream->total_out / stream->total_in);
628 if (state->compression_out_failures == 0)
629 deflateEnd(stream);
630 }
631 if (state->compression_in_started) {
632 z_streamp stream = &state->compression_in_stream;
633 debug("compress incoming: "
634 "raw data %llu, compressed %llu, factor %.2f",
635 (unsigned long long)stream->total_out,
636 (unsigned long long)stream->total_in,
637 stream->total_out == 0 ? 0.0 :
638 (double) stream->total_in / stream->total_out);
639 if (state->compression_in_failures == 0)
640 inflateEnd(stream);
641 }
642 }
643 #endif /* WITH_ZLIB */
644 cipher_free(state->send_context);
645 cipher_free(state->receive_context);
646 state->send_context = state->receive_context = NULL;
647 if (do_close) {
648 free(ssh->local_ipaddr);
649 ssh->local_ipaddr = NULL;
650 free(ssh->remote_ipaddr);
651 ssh->remote_ipaddr = NULL;
652 free(ssh->state);
653 ssh->state = NULL;
654 }
655 }
656
657 void
ssh_packet_close(struct ssh * ssh)658 ssh_packet_close(struct ssh *ssh)
659 {
660 ssh_packet_close_internal(ssh, 1);
661 }
662
663 void
ssh_packet_clear_keys(struct ssh * ssh)664 ssh_packet_clear_keys(struct ssh *ssh)
665 {
666 ssh_packet_close_internal(ssh, 0);
667 }
668
669 /* Sets remote side protocol flags. */
670
671 void
ssh_packet_set_protocol_flags(struct ssh * ssh,u_int protocol_flags)672 ssh_packet_set_protocol_flags(struct ssh *ssh, u_int protocol_flags)
673 {
674 ssh->state->remote_protocol_flags = protocol_flags;
675 }
676
677 /* Returns the remote protocol flags set earlier by the above function. */
678
679 u_int
ssh_packet_get_protocol_flags(struct ssh * ssh)680 ssh_packet_get_protocol_flags(struct ssh *ssh)
681 {
682 return ssh->state->remote_protocol_flags;
683 }
684
685 /*
686 * Starts packet compression from the next packet on in both directions.
687 * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip.
688 */
689
690 static int
ssh_packet_init_compression(struct ssh * ssh)691 ssh_packet_init_compression(struct ssh *ssh)
692 {
693 if (!ssh->state->compression_buffer &&
694 ((ssh->state->compression_buffer = sshbuf_new()) == NULL))
695 return SSH_ERR_ALLOC_FAIL;
696 return 0;
697 }
698
699 #ifdef WITH_ZLIB
700 static int
start_compression_out(struct ssh * ssh,int level)701 start_compression_out(struct ssh *ssh, int level)
702 {
703 if (level < 1 || level > 9)
704 return SSH_ERR_INVALID_ARGUMENT;
705 debug("Enabling compression at level %d.", level);
706 if (ssh->state->compression_out_started == 1)
707 deflateEnd(&ssh->state->compression_out_stream);
708 switch (deflateInit(&ssh->state->compression_out_stream, level)) {
709 case Z_OK:
710 ssh->state->compression_out_started = 1;
711 break;
712 case Z_MEM_ERROR:
713 return SSH_ERR_ALLOC_FAIL;
714 default:
715 return SSH_ERR_INTERNAL_ERROR;
716 }
717 return 0;
718 }
719
720 static int
start_compression_in(struct ssh * ssh)721 start_compression_in(struct ssh *ssh)
722 {
723 if (ssh->state->compression_in_started == 1)
724 inflateEnd(&ssh->state->compression_in_stream);
725 switch (inflateInit(&ssh->state->compression_in_stream)) {
726 case Z_OK:
727 ssh->state->compression_in_started = 1;
728 break;
729 case Z_MEM_ERROR:
730 return SSH_ERR_ALLOC_FAIL;
731 default:
732 return SSH_ERR_INTERNAL_ERROR;
733 }
734 return 0;
735 }
736
737 /* XXX remove need for separate compression buffer */
738 static int
compress_buffer(struct ssh * ssh,struct sshbuf * in,struct sshbuf * out)739 compress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out)
740 {
741 u_char buf[4096];
742 int r, status;
743
744 if (ssh->state->compression_out_started != 1)
745 return SSH_ERR_INTERNAL_ERROR;
746
747 /* This case is not handled below. */
748 if (sshbuf_len(in) == 0)
749 return 0;
750
751 /* Input is the contents of the input buffer. */
752 if ((ssh->state->compression_out_stream.next_in =
753 sshbuf_mutable_ptr(in)) == NULL)
754 return SSH_ERR_INTERNAL_ERROR;
755 ssh->state->compression_out_stream.avail_in = sshbuf_len(in);
756
757 /* Loop compressing until deflate() returns with avail_out != 0. */
758 do {
759 /* Set up fixed-size output buffer. */
760 ssh->state->compression_out_stream.next_out = buf;
761 ssh->state->compression_out_stream.avail_out = sizeof(buf);
762
763 /* Compress as much data into the buffer as possible. */
764 status = deflate(&ssh->state->compression_out_stream,
765 Z_PARTIAL_FLUSH);
766 switch (status) {
767 case Z_MEM_ERROR:
768 return SSH_ERR_ALLOC_FAIL;
769 case Z_OK:
770 /* Append compressed data to output_buffer. */
771 if ((r = sshbuf_put(out, buf, sizeof(buf) -
772 ssh->state->compression_out_stream.avail_out)) != 0)
773 return r;
774 break;
775 case Z_STREAM_ERROR:
776 default:
777 ssh->state->compression_out_failures++;
778 return SSH_ERR_INVALID_FORMAT;
779 }
780 } while (ssh->state->compression_out_stream.avail_out == 0);
781 return 0;
782 }
783
784 static int
uncompress_buffer(struct ssh * ssh,struct sshbuf * in,struct sshbuf * out)785 uncompress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out)
786 {
787 u_char buf[4096];
788 int r, status;
789
790 if (ssh->state->compression_in_started != 1)
791 return SSH_ERR_INTERNAL_ERROR;
792
793 if ((ssh->state->compression_in_stream.next_in =
794 sshbuf_mutable_ptr(in)) == NULL)
795 return SSH_ERR_INTERNAL_ERROR;
796 ssh->state->compression_in_stream.avail_in = sshbuf_len(in);
797
798 for (;;) {
799 /* Set up fixed-size output buffer. */
800 ssh->state->compression_in_stream.next_out = buf;
801 ssh->state->compression_in_stream.avail_out = sizeof(buf);
802
803 status = inflate(&ssh->state->compression_in_stream,
804 Z_PARTIAL_FLUSH);
805 switch (status) {
806 case Z_OK:
807 if ((r = sshbuf_put(out, buf, sizeof(buf) -
808 ssh->state->compression_in_stream.avail_out)) != 0)
809 return r;
810 break;
811 case Z_BUF_ERROR:
812 /*
813 * Comments in zlib.h say that we should keep calling
814 * inflate() until we get an error. This appears to
815 * be the error that we get.
816 */
817 return 0;
818 case Z_DATA_ERROR:
819 return SSH_ERR_INVALID_FORMAT;
820 case Z_MEM_ERROR:
821 return SSH_ERR_ALLOC_FAIL;
822 case Z_STREAM_ERROR:
823 default:
824 ssh->state->compression_in_failures++;
825 return SSH_ERR_INTERNAL_ERROR;
826 }
827 }
828 /* NOTREACHED */
829 }
830
831 #else /* WITH_ZLIB */
832
833 static int
start_compression_out(struct ssh * ssh,int level)834 start_compression_out(struct ssh *ssh, int level)
835 {
836 return SSH_ERR_INTERNAL_ERROR;
837 }
838
839 static int
start_compression_in(struct ssh * ssh)840 start_compression_in(struct ssh *ssh)
841 {
842 return SSH_ERR_INTERNAL_ERROR;
843 }
844
845 static int
compress_buffer(struct ssh * ssh,struct sshbuf * in,struct sshbuf * out)846 compress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out)
847 {
848 return SSH_ERR_INTERNAL_ERROR;
849 }
850
851 static int
uncompress_buffer(struct ssh * ssh,struct sshbuf * in,struct sshbuf * out)852 uncompress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out)
853 {
854 return SSH_ERR_INTERNAL_ERROR;
855 }
856 #endif /* WITH_ZLIB */
857
858 void
ssh_clear_newkeys(struct ssh * ssh,int mode)859 ssh_clear_newkeys(struct ssh *ssh, int mode)
860 {
861 if (ssh->kex && ssh->kex->newkeys[mode]) {
862 kex_free_newkeys(ssh->kex->newkeys[mode]);
863 ssh->kex->newkeys[mode] = NULL;
864 }
865 }
866
867 int
ssh_set_newkeys(struct ssh * ssh,int mode)868 ssh_set_newkeys(struct ssh *ssh, int mode)
869 {
870 struct session_state *state = ssh->state;
871 struct sshenc *enc;
872 struct sshmac *mac;
873 struct sshcomp *comp;
874 struct sshcipher_ctx **ccp;
875 struct packet_state *ps;
876 u_int64_t *max_blocks;
877 const char *wmsg;
878 int r, crypt_type;
879 const char *dir = mode == MODE_OUT ? "out" : "in";
880
881 debug2("set_newkeys: mode %d", mode);
882
883 if (mode == MODE_OUT) {
884 ccp = &state->send_context;
885 crypt_type = CIPHER_ENCRYPT;
886 ps = &state->p_send;
887 max_blocks = &state->max_blocks_out;
888 } else {
889 ccp = &state->receive_context;
890 crypt_type = CIPHER_DECRYPT;
891 ps = &state->p_read;
892 max_blocks = &state->max_blocks_in;
893 }
894 if (state->newkeys[mode] != NULL) {
895 debug("%s: rekeying %s, input %llu bytes %llu blocks, "
896 "output %llu bytes %llu blocks", __func__, dir,
897 (unsigned long long)state->p_read.bytes,
898 (unsigned long long)state->p_read.blocks,
899 (unsigned long long)state->p_send.bytes,
900 (unsigned long long)state->p_send.blocks);
901 kex_free_newkeys(state->newkeys[mode]);
902 state->newkeys[mode] = NULL;
903 }
904 /* note that both bytes and the seqnr are not reset */
905 ps->packets = ps->blocks = 0;
906 /* move newkeys from kex to state */
907 if ((state->newkeys[mode] = ssh->kex->newkeys[mode]) == NULL)
908 return SSH_ERR_INTERNAL_ERROR;
909 ssh->kex->newkeys[mode] = NULL;
910 enc = &state->newkeys[mode]->enc;
911 mac = &state->newkeys[mode]->mac;
912 comp = &state->newkeys[mode]->comp;
913 if (cipher_authlen(enc->cipher) == 0) {
914 if ((r = mac_init(mac)) != 0)
915 return r;
916 }
917 mac->enabled = 1;
918 DBG(debug("%s: cipher_init_context: %s", __func__, dir));
919 cipher_free(*ccp);
920 *ccp = NULL;
921 if ((r = cipher_init(ccp, enc->cipher, enc->key, enc->key_len,
922 enc->iv, enc->iv_len, crypt_type)) != 0)
923 return r;
924 if (!state->cipher_warning_done &&
925 (wmsg = cipher_warning_message(*ccp)) != NULL) {
926 error("Warning: %s", wmsg);
927 state->cipher_warning_done = 1;
928 }
929 /* Deleting the keys does not gain extra security */
930 /* explicit_bzero(enc->iv, enc->block_size);
931 explicit_bzero(enc->key, enc->key_len);
932 explicit_bzero(mac->key, mac->key_len); */
933 if ((comp->type == COMP_ZLIB ||
934 (comp->type == COMP_DELAYED &&
935 state->after_authentication)) && comp->enabled == 0) {
936 if ((r = ssh_packet_init_compression(ssh)) < 0)
937 return r;
938 if (mode == MODE_OUT) {
939 if ((r = start_compression_out(ssh, 6)) != 0)
940 return r;
941 } else {
942 if ((r = start_compression_in(ssh)) != 0)
943 return r;
944 }
945 comp->enabled = 1;
946 }
947 /*
948 * The 2^(blocksize*2) limit is too expensive for 3DES,
949 * so enforce a 1GB limit for small blocksizes.
950 * See RFC4344 section 3.2.
951 */
952 if (enc->block_size >= 16)
953 *max_blocks = (u_int64_t)1 << (enc->block_size*2);
954 else
955 *max_blocks = ((u_int64_t)1 << 30) / enc->block_size;
956 if (state->rekey_limit)
957 *max_blocks = MINIMUM(*max_blocks,
958 state->rekey_limit / enc->block_size);
959 debug("rekey %s after %llu blocks", dir,
960 (unsigned long long)*max_blocks);
961 return 0;
962 }
963
964 #define MAX_PACKETS (1U<<31)
965 static int
ssh_packet_need_rekeying(struct ssh * ssh,u_int outbound_packet_len)966 ssh_packet_need_rekeying(struct ssh *ssh, u_int outbound_packet_len)
967 {
968 struct session_state *state = ssh->state;
969 u_int32_t out_blocks;
970
971 /* XXX client can't cope with rekeying pre-auth */
972 if (!state->after_authentication)
973 return 0;
974
975 /* Haven't keyed yet or KEX in progress. */
976 if (ssh_packet_is_rekeying(ssh))
977 return 0;
978
979 /* Peer can't rekey */
980 if (ssh->compat & SSH_BUG_NOREKEY)
981 return 0;
982
983 /*
984 * Permit one packet in or out per rekey - this allows us to
985 * make progress when rekey limits are very small.
986 */
987 if (state->p_send.packets == 0 && state->p_read.packets == 0)
988 return 0;
989
990 /* Time-based rekeying */
991 if (state->rekey_interval != 0 &&
992 (int64_t)state->rekey_time + state->rekey_interval <= monotime())
993 return 1;
994
995 /*
996 * Always rekey when MAX_PACKETS sent in either direction
997 * As per RFC4344 section 3.1 we do this after 2^31 packets.
998 */
999 if (state->p_send.packets > MAX_PACKETS ||
1000 state->p_read.packets > MAX_PACKETS)
1001 return 1;
1002
1003 /* Rekey after (cipher-specific) maximum blocks */
1004 out_blocks = ROUNDUP(outbound_packet_len,
1005 state->newkeys[MODE_OUT]->enc.block_size);
1006 return (state->max_blocks_out &&
1007 (state->p_send.blocks + out_blocks > state->max_blocks_out)) ||
1008 (state->max_blocks_in &&
1009 (state->p_read.blocks > state->max_blocks_in));
1010 }
1011
1012 /*
1013 * Delayed compression for SSH2 is enabled after authentication:
1014 * This happens on the server side after a SSH2_MSG_USERAUTH_SUCCESS is sent,
1015 * and on the client side after a SSH2_MSG_USERAUTH_SUCCESS is received.
1016 */
1017 static int
ssh_packet_enable_delayed_compress(struct ssh * ssh)1018 ssh_packet_enable_delayed_compress(struct ssh *ssh)
1019 {
1020 struct session_state *state = ssh->state;
1021 struct sshcomp *comp = NULL;
1022 int r, mode;
1023
1024 /*
1025 * Remember that we are past the authentication step, so rekeying
1026 * with COMP_DELAYED will turn on compression immediately.
1027 */
1028 state->after_authentication = 1;
1029 for (mode = 0; mode < MODE_MAX; mode++) {
1030 /* protocol error: USERAUTH_SUCCESS received before NEWKEYS */
1031 if (state->newkeys[mode] == NULL)
1032 continue;
1033 comp = &state->newkeys[mode]->comp;
1034 if (comp && !comp->enabled && comp->type == COMP_DELAYED) {
1035 if ((r = ssh_packet_init_compression(ssh)) != 0)
1036 return r;
1037 if (mode == MODE_OUT) {
1038 if ((r = start_compression_out(ssh, 6)) != 0)
1039 return r;
1040 } else {
1041 if ((r = start_compression_in(ssh)) != 0)
1042 return r;
1043 }
1044 comp->enabled = 1;
1045 }
1046 }
1047 return 0;
1048 }
1049
1050 /* Used to mute debug logging for noisy packet types */
1051 int
ssh_packet_log_type(u_char type)1052 ssh_packet_log_type(u_char type)
1053 {
1054 switch (type) {
1055 case SSH2_MSG_CHANNEL_DATA:
1056 case SSH2_MSG_CHANNEL_EXTENDED_DATA:
1057 case SSH2_MSG_CHANNEL_WINDOW_ADJUST:
1058 return 0;
1059 default:
1060 return 1;
1061 }
1062 }
1063
1064 /*
1065 * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue)
1066 */
1067 int
ssh_packet_send2_wrapped(struct ssh * ssh)1068 ssh_packet_send2_wrapped(struct ssh *ssh)
1069 {
1070 struct session_state *state = ssh->state;
1071 u_char type, *cp, macbuf[SSH_DIGEST_MAX_LENGTH];
1072 u_char tmp, padlen, pad = 0;
1073 u_int authlen = 0, aadlen = 0;
1074 u_int len;
1075 struct sshenc *enc = NULL;
1076 struct sshmac *mac = NULL;
1077 struct sshcomp *comp = NULL;
1078 int r, block_size;
1079
1080 if (state->newkeys[MODE_OUT] != NULL) {
1081 enc = &state->newkeys[MODE_OUT]->enc;
1082 mac = &state->newkeys[MODE_OUT]->mac;
1083 comp = &state->newkeys[MODE_OUT]->comp;
1084 /* disable mac for authenticated encryption */
1085 if ((authlen = cipher_authlen(enc->cipher)) != 0)
1086 mac = NULL;
1087 }
1088 block_size = enc ? enc->block_size : 8;
1089 aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0;
1090
1091 type = (sshbuf_ptr(state->outgoing_packet))[5];
1092 if (ssh_packet_log_type(type))
1093 debug3("send packet: type %u", type);
1094 #ifdef PACKET_DEBUG
1095 fprintf(stderr, "plain: ");
1096 sshbuf_dump(state->outgoing_packet, stderr);
1097 #endif
1098
1099 if (comp && comp->enabled) {
1100 len = sshbuf_len(state->outgoing_packet);
1101 /* skip header, compress only payload */
1102 if ((r = sshbuf_consume(state->outgoing_packet, 5)) != 0)
1103 goto out;
1104 sshbuf_reset(state->compression_buffer);
1105 if ((r = compress_buffer(ssh, state->outgoing_packet,
1106 state->compression_buffer)) != 0)
1107 goto out;
1108 sshbuf_reset(state->outgoing_packet);
1109 if ((r = sshbuf_put(state->outgoing_packet,
1110 "\0\0\0\0\0", 5)) != 0 ||
1111 (r = sshbuf_putb(state->outgoing_packet,
1112 state->compression_buffer)) != 0)
1113 goto out;
1114 DBG(debug("compression: raw %d compressed %zd", len,
1115 sshbuf_len(state->outgoing_packet)));
1116 }
1117
1118 /* sizeof (packet_len + pad_len + payload) */
1119 len = sshbuf_len(state->outgoing_packet);
1120
1121 /*
1122 * calc size of padding, alloc space, get random data,
1123 * minimum padding is 4 bytes
1124 */
1125 len -= aadlen; /* packet length is not encrypted for EtM modes */
1126 padlen = block_size - (len % block_size);
1127 if (padlen < 4)
1128 padlen += block_size;
1129 if (state->extra_pad) {
1130 tmp = state->extra_pad;
1131 state->extra_pad =
1132 ROUNDUP(state->extra_pad, block_size);
1133 /* check if roundup overflowed */
1134 if (state->extra_pad < tmp)
1135 return SSH_ERR_INVALID_ARGUMENT;
1136 tmp = (len + padlen) % state->extra_pad;
1137 /* Check whether pad calculation below will underflow */
1138 if (tmp > state->extra_pad)
1139 return SSH_ERR_INVALID_ARGUMENT;
1140 pad = state->extra_pad - tmp;
1141 DBG(debug3("%s: adding %d (len %d padlen %d extra_pad %d)",
1142 __func__, pad, len, padlen, state->extra_pad));
1143 tmp = padlen;
1144 padlen += pad;
1145 /* Check whether padlen calculation overflowed */
1146 if (padlen < tmp)
1147 return SSH_ERR_INVALID_ARGUMENT; /* overflow */
1148 state->extra_pad = 0;
1149 }
1150 if ((r = sshbuf_reserve(state->outgoing_packet, padlen, &cp)) != 0)
1151 goto out;
1152 if (enc && !cipher_ctx_is_plaintext(state->send_context)) {
1153 /* random padding */
1154 arc4random_buf(cp, padlen);
1155 } else {
1156 /* clear padding */
1157 explicit_bzero(cp, padlen);
1158 }
1159 /* sizeof (packet_len + pad_len + payload + padding) */
1160 len = sshbuf_len(state->outgoing_packet);
1161 cp = sshbuf_mutable_ptr(state->outgoing_packet);
1162 if (cp == NULL) {
1163 r = SSH_ERR_INTERNAL_ERROR;
1164 goto out;
1165 }
1166 /* packet_length includes payload, padding and padding length field */
1167 POKE_U32(cp, len - 4);
1168 cp[4] = padlen;
1169 DBG(debug("send: len %d (includes padlen %d, aadlen %d)",
1170 len, padlen, aadlen));
1171
1172 /* compute MAC over seqnr and packet(length fields, payload, padding) */
1173 if (mac && mac->enabled && !mac->etm) {
1174 if ((r = mac_compute(mac, state->p_send.seqnr,
1175 sshbuf_ptr(state->outgoing_packet), len,
1176 macbuf, sizeof(macbuf))) != 0)
1177 goto out;
1178 DBG(debug("done calc MAC out #%d", state->p_send.seqnr));
1179 }
1180 /* encrypt packet and append to output buffer. */
1181 if ((r = sshbuf_reserve(state->output,
1182 sshbuf_len(state->outgoing_packet) + authlen, &cp)) != 0)
1183 goto out;
1184 if ((r = cipher_crypt(state->send_context, state->p_send.seqnr, cp,
1185 sshbuf_ptr(state->outgoing_packet),
1186 len - aadlen, aadlen, authlen)) != 0)
1187 goto out;
1188 /* append unencrypted MAC */
1189 if (mac && mac->enabled) {
1190 if (mac->etm) {
1191 /* EtM: compute mac over aadlen + cipher text */
1192 if ((r = mac_compute(mac, state->p_send.seqnr,
1193 cp, len, macbuf, sizeof(macbuf))) != 0)
1194 goto out;
1195 DBG(debug("done calc MAC(EtM) out #%d",
1196 state->p_send.seqnr));
1197 }
1198 if ((r = sshbuf_put(state->output, macbuf, mac->mac_len)) != 0)
1199 goto out;
1200 }
1201 #ifdef PACKET_DEBUG
1202 fprintf(stderr, "encrypted: ");
1203 sshbuf_dump(state->output, stderr);
1204 #endif
1205 /* increment sequence number for outgoing packets */
1206 if (++state->p_send.seqnr == 0)
1207 logit("outgoing seqnr wraps around");
1208 if (++state->p_send.packets == 0)
1209 if (!(ssh->compat & SSH_BUG_NOREKEY))
1210 return SSH_ERR_NEED_REKEY;
1211 state->p_send.blocks += len / block_size;
1212 state->p_send.bytes += len;
1213 sshbuf_reset(state->outgoing_packet);
1214
1215 if (type == SSH2_MSG_NEWKEYS)
1216 r = ssh_set_newkeys(ssh, MODE_OUT);
1217 else if (type == SSH2_MSG_USERAUTH_SUCCESS && state->server_side)
1218 r = ssh_packet_enable_delayed_compress(ssh);
1219 else
1220 r = 0;
1221 out:
1222 return r;
1223 }
1224
1225 /* returns non-zero if the specified packet type is usec by KEX */
1226 static int
ssh_packet_type_is_kex(u_char type)1227 ssh_packet_type_is_kex(u_char type)
1228 {
1229 return
1230 type >= SSH2_MSG_TRANSPORT_MIN &&
1231 type <= SSH2_MSG_TRANSPORT_MAX &&
1232 type != SSH2_MSG_SERVICE_REQUEST &&
1233 type != SSH2_MSG_SERVICE_ACCEPT &&
1234 type != SSH2_MSG_EXT_INFO;
1235 }
1236
1237 int
ssh_packet_send2(struct ssh * ssh)1238 ssh_packet_send2(struct ssh *ssh)
1239 {
1240 struct session_state *state = ssh->state;
1241 struct packet *p;
1242 u_char type;
1243 int r, need_rekey;
1244
1245 if (sshbuf_len(state->outgoing_packet) < 6)
1246 return SSH_ERR_INTERNAL_ERROR;
1247 type = sshbuf_ptr(state->outgoing_packet)[5];
1248 need_rekey = !ssh_packet_type_is_kex(type) &&
1249 ssh_packet_need_rekeying(ssh, sshbuf_len(state->outgoing_packet));
1250
1251 /*
1252 * During rekeying we can only send key exchange messages.
1253 * Queue everything else.
1254 */
1255 if ((need_rekey || state->rekeying) && !ssh_packet_type_is_kex(type)) {
1256 if (need_rekey)
1257 debug3("%s: rekex triggered", __func__);
1258 debug("enqueue packet: %u", type);
1259 p = calloc(1, sizeof(*p));
1260 if (p == NULL)
1261 return SSH_ERR_ALLOC_FAIL;
1262 p->type = type;
1263 p->payload = state->outgoing_packet;
1264 TAILQ_INSERT_TAIL(&state->outgoing, p, next);
1265 state->outgoing_packet = sshbuf_new();
1266 if (state->outgoing_packet == NULL)
1267 return SSH_ERR_ALLOC_FAIL;
1268 if (need_rekey) {
1269 /*
1270 * This packet triggered a rekey, so send the
1271 * KEXINIT now.
1272 * NB. reenters this function via kex_start_rekex().
1273 */
1274 return kex_start_rekex(ssh);
1275 }
1276 return 0;
1277 }
1278
1279 /* rekeying starts with sending KEXINIT */
1280 if (type == SSH2_MSG_KEXINIT)
1281 state->rekeying = 1;
1282
1283 if ((r = ssh_packet_send2_wrapped(ssh)) != 0)
1284 return r;
1285
1286 /* after a NEWKEYS message we can send the complete queue */
1287 if (type == SSH2_MSG_NEWKEYS) {
1288 state->rekeying = 0;
1289 state->rekey_time = monotime();
1290 while ((p = TAILQ_FIRST(&state->outgoing))) {
1291 type = p->type;
1292 /*
1293 * If this packet triggers a rekex, then skip the
1294 * remaining packets in the queue for now.
1295 * NB. re-enters this function via kex_start_rekex.
1296 */
1297 if (ssh_packet_need_rekeying(ssh,
1298 sshbuf_len(p->payload))) {
1299 debug3("%s: queued packet triggered rekex",
1300 __func__);
1301 return kex_start_rekex(ssh);
1302 }
1303 debug("dequeue packet: %u", type);
1304 sshbuf_free(state->outgoing_packet);
1305 state->outgoing_packet = p->payload;
1306 TAILQ_REMOVE(&state->outgoing, p, next);
1307 memset(p, 0, sizeof(*p));
1308 free(p);
1309 if ((r = ssh_packet_send2_wrapped(ssh)) != 0)
1310 return r;
1311 }
1312 }
1313 return 0;
1314 }
1315
1316 /*
1317 * Waits until a packet has been received, and returns its type. Note that
1318 * no other data is processed until this returns, so this function should not
1319 * be used during the interactive session.
1320 */
1321
1322 int
ssh_packet_read_seqnr(struct ssh * ssh,u_char * typep,u_int32_t * seqnr_p)1323 ssh_packet_read_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
1324 {
1325 struct session_state *state = ssh->state;
1326 int len, r, ms_remain;
1327 fd_set *setp;
1328 char buf[8192];
1329 struct timeval timeout, start, *timeoutp = NULL;
1330
1331 DBG(debug("packet_read()"));
1332
1333 setp = calloc(howmany(state->connection_in + 1,
1334 NFDBITS), sizeof(fd_mask));
1335 if (setp == NULL)
1336 return SSH_ERR_ALLOC_FAIL;
1337
1338 /*
1339 * Since we are blocking, ensure that all written packets have
1340 * been sent.
1341 */
1342 if ((r = ssh_packet_write_wait(ssh)) != 0)
1343 goto out;
1344
1345 /* Stay in the loop until we have received a complete packet. */
1346 for (;;) {
1347 /* Try to read a packet from the buffer. */
1348 r = ssh_packet_read_poll_seqnr(ssh, typep, seqnr_p);
1349 if (r != 0)
1350 break;
1351 /* If we got a packet, return it. */
1352 if (*typep != SSH_MSG_NONE)
1353 break;
1354 /*
1355 * Otherwise, wait for some data to arrive, add it to the
1356 * buffer, and try again.
1357 */
1358 memset(setp, 0, howmany(state->connection_in + 1,
1359 NFDBITS) * sizeof(fd_mask));
1360 FD_SET(state->connection_in, setp);
1361
1362 if (state->packet_timeout_ms > 0) {
1363 ms_remain = state->packet_timeout_ms;
1364 timeoutp = &timeout;
1365 }
1366 /* Wait for some data to arrive. */
1367 for (;;) {
1368 if (state->packet_timeout_ms > 0) {
1369 ms_to_timeval(&timeout, ms_remain);
1370 monotime_tv(&start);
1371 }
1372 if ((r = select(state->connection_in + 1, setp,
1373 NULL, NULL, timeoutp)) >= 0)
1374 break;
1375 if (errno != EAGAIN && errno != EINTR &&
1376 errno != EWOULDBLOCK) {
1377 r = SSH_ERR_SYSTEM_ERROR;
1378 goto out;
1379 }
1380 if (state->packet_timeout_ms <= 0)
1381 continue;
1382 ms_subtract_diff(&start, &ms_remain);
1383 if (ms_remain <= 0) {
1384 r = 0;
1385 break;
1386 }
1387 }
1388 if (r == 0) {
1389 r = SSH_ERR_CONN_TIMEOUT;
1390 goto out;
1391 }
1392 /* Read data from the socket. */
1393 len = read(state->connection_in, buf, sizeof(buf));
1394 if (len == 0) {
1395 r = SSH_ERR_CONN_CLOSED;
1396 goto out;
1397 }
1398 if (len == -1) {
1399 r = SSH_ERR_SYSTEM_ERROR;
1400 goto out;
1401 }
1402
1403 /* Append it to the buffer. */
1404 if ((r = ssh_packet_process_incoming(ssh, buf, len)) != 0)
1405 goto out;
1406 }
1407 out:
1408 free(setp);
1409 return r;
1410 }
1411
1412 int
ssh_packet_read(struct ssh * ssh)1413 ssh_packet_read(struct ssh *ssh)
1414 {
1415 u_char type;
1416 int r;
1417
1418 if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0)
1419 fatal("%s: %s", __func__, ssh_err(r));
1420 return type;
1421 }
1422
1423 /*
1424 * Waits until a packet has been received, verifies that its type matches
1425 * that given, and gives a fatal error and exits if there is a mismatch.
1426 */
1427
1428 int
ssh_packet_read_expect(struct ssh * ssh,u_int expected_type)1429 ssh_packet_read_expect(struct ssh *ssh, u_int expected_type)
1430 {
1431 int r;
1432 u_char type;
1433
1434 if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0)
1435 return r;
1436 if (type != expected_type) {
1437 if ((r = sshpkt_disconnect(ssh,
1438 "Protocol error: expected packet type %d, got %d",
1439 expected_type, type)) != 0)
1440 return r;
1441 return SSH_ERR_PROTOCOL_ERROR;
1442 }
1443 return 0;
1444 }
1445
1446 static int
ssh_packet_read_poll2_mux(struct ssh * ssh,u_char * typep,u_int32_t * seqnr_p)1447 ssh_packet_read_poll2_mux(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
1448 {
1449 struct session_state *state = ssh->state;
1450 const u_char *cp;
1451 size_t need;
1452 int r;
1453
1454 if (ssh->kex)
1455 return SSH_ERR_INTERNAL_ERROR;
1456 *typep = SSH_MSG_NONE;
1457 cp = sshbuf_ptr(state->input);
1458 if (state->packlen == 0) {
1459 if (sshbuf_len(state->input) < 4 + 1)
1460 return 0; /* packet is incomplete */
1461 state->packlen = PEEK_U32(cp);
1462 if (state->packlen < 4 + 1 ||
1463 state->packlen > PACKET_MAX_SIZE)
1464 return SSH_ERR_MESSAGE_INCOMPLETE;
1465 }
1466 need = state->packlen + 4;
1467 if (sshbuf_len(state->input) < need)
1468 return 0; /* packet is incomplete */
1469 sshbuf_reset(state->incoming_packet);
1470 if ((r = sshbuf_put(state->incoming_packet, cp + 4,
1471 state->packlen)) != 0 ||
1472 (r = sshbuf_consume(state->input, need)) != 0 ||
1473 (r = sshbuf_get_u8(state->incoming_packet, NULL)) != 0 ||
1474 (r = sshbuf_get_u8(state->incoming_packet, typep)) != 0)
1475 return r;
1476 if (ssh_packet_log_type(*typep))
1477 debug3("%s: type %u", __func__, *typep);
1478 /* sshbuf_dump(state->incoming_packet, stderr); */
1479 /* reset for next packet */
1480 state->packlen = 0;
1481 return r;
1482 }
1483
1484 int
ssh_packet_read_poll2(struct ssh * ssh,u_char * typep,u_int32_t * seqnr_p)1485 ssh_packet_read_poll2(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
1486 {
1487 struct session_state *state = ssh->state;
1488 u_int padlen, need;
1489 u_char *cp;
1490 u_int maclen, aadlen = 0, authlen = 0, block_size;
1491 struct sshenc *enc = NULL;
1492 struct sshmac *mac = NULL;
1493 struct sshcomp *comp = NULL;
1494 int r;
1495
1496 if (state->mux)
1497 return ssh_packet_read_poll2_mux(ssh, typep, seqnr_p);
1498
1499 *typep = SSH_MSG_NONE;
1500
1501 if (state->packet_discard)
1502 return 0;
1503
1504 if (state->newkeys[MODE_IN] != NULL) {
1505 enc = &state->newkeys[MODE_IN]->enc;
1506 mac = &state->newkeys[MODE_IN]->mac;
1507 comp = &state->newkeys[MODE_IN]->comp;
1508 /* disable mac for authenticated encryption */
1509 if ((authlen = cipher_authlen(enc->cipher)) != 0)
1510 mac = NULL;
1511 }
1512 maclen = mac && mac->enabled ? mac->mac_len : 0;
1513 block_size = enc ? enc->block_size : 8;
1514 aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0;
1515
1516 if (aadlen && state->packlen == 0) {
1517 if (cipher_get_length(state->receive_context,
1518 &state->packlen, state->p_read.seqnr,
1519 sshbuf_ptr(state->input), sshbuf_len(state->input)) != 0)
1520 return 0;
1521 if (state->packlen < 1 + 4 ||
1522 state->packlen > PACKET_MAX_SIZE) {
1523 #ifdef PACKET_DEBUG
1524 sshbuf_dump(state->input, stderr);
1525 #endif
1526 logit("Bad packet length %u.", state->packlen);
1527 if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0)
1528 return r;
1529 return SSH_ERR_CONN_CORRUPT;
1530 }
1531 sshbuf_reset(state->incoming_packet);
1532 } else if (state->packlen == 0) {
1533 /*
1534 * check if input size is less than the cipher block size,
1535 * decrypt first block and extract length of incoming packet
1536 */
1537 if (sshbuf_len(state->input) < block_size)
1538 return 0;
1539 sshbuf_reset(state->incoming_packet);
1540 if ((r = sshbuf_reserve(state->incoming_packet, block_size,
1541 &cp)) != 0)
1542 goto out;
1543 if ((r = cipher_crypt(state->receive_context,
1544 state->p_send.seqnr, cp, sshbuf_ptr(state->input),
1545 block_size, 0, 0)) != 0)
1546 goto out;
1547 state->packlen = PEEK_U32(sshbuf_ptr(state->incoming_packet));
1548 if (state->packlen < 1 + 4 ||
1549 state->packlen > PACKET_MAX_SIZE) {
1550 #ifdef PACKET_DEBUG
1551 fprintf(stderr, "input: \n");
1552 sshbuf_dump(state->input, stderr);
1553 fprintf(stderr, "incoming_packet: \n");
1554 sshbuf_dump(state->incoming_packet, stderr);
1555 #endif
1556 logit("Bad packet length %u.", state->packlen);
1557 return ssh_packet_start_discard(ssh, enc, mac, 0,
1558 PACKET_MAX_SIZE);
1559 }
1560 if ((r = sshbuf_consume(state->input, block_size)) != 0)
1561 goto out;
1562 }
1563 DBG(debug("input: packet len %u", state->packlen+4));
1564
1565 if (aadlen) {
1566 /* only the payload is encrypted */
1567 need = state->packlen;
1568 } else {
1569 /*
1570 * the payload size and the payload are encrypted, but we
1571 * have a partial packet of block_size bytes
1572 */
1573 need = 4 + state->packlen - block_size;
1574 }
1575 DBG(debug("partial packet: block %d, need %d, maclen %d, authlen %d,"
1576 " aadlen %d", block_size, need, maclen, authlen, aadlen));
1577 if (need % block_size != 0) {
1578 logit("padding error: need %d block %d mod %d",
1579 need, block_size, need % block_size);
1580 return ssh_packet_start_discard(ssh, enc, mac, 0,
1581 PACKET_MAX_SIZE - block_size);
1582 }
1583 /*
1584 * check if the entire packet has been received and
1585 * decrypt into incoming_packet:
1586 * 'aadlen' bytes are unencrypted, but authenticated.
1587 * 'need' bytes are encrypted, followed by either
1588 * 'authlen' bytes of authentication tag or
1589 * 'maclen' bytes of message authentication code.
1590 */
1591 if (sshbuf_len(state->input) < aadlen + need + authlen + maclen)
1592 return 0; /* packet is incomplete */
1593 #ifdef PACKET_DEBUG
1594 fprintf(stderr, "read_poll enc/full: ");
1595 sshbuf_dump(state->input, stderr);
1596 #endif
1597 /* EtM: check mac over encrypted input */
1598 if (mac && mac->enabled && mac->etm) {
1599 if ((r = mac_check(mac, state->p_read.seqnr,
1600 sshbuf_ptr(state->input), aadlen + need,
1601 sshbuf_ptr(state->input) + aadlen + need + authlen,
1602 maclen)) != 0) {
1603 if (r == SSH_ERR_MAC_INVALID)
1604 logit("Corrupted MAC on input.");
1605 goto out;
1606 }
1607 }
1608 if ((r = sshbuf_reserve(state->incoming_packet, aadlen + need,
1609 &cp)) != 0)
1610 goto out;
1611 if ((r = cipher_crypt(state->receive_context, state->p_read.seqnr, cp,
1612 sshbuf_ptr(state->input), need, aadlen, authlen)) != 0)
1613 goto out;
1614 if ((r = sshbuf_consume(state->input, aadlen + need + authlen)) != 0)
1615 goto out;
1616 if (mac && mac->enabled) {
1617 /* Not EtM: check MAC over cleartext */
1618 if (!mac->etm && (r = mac_check(mac, state->p_read.seqnr,
1619 sshbuf_ptr(state->incoming_packet),
1620 sshbuf_len(state->incoming_packet),
1621 sshbuf_ptr(state->input), maclen)) != 0) {
1622 if (r != SSH_ERR_MAC_INVALID)
1623 goto out;
1624 logit("Corrupted MAC on input.");
1625 if (need + block_size > PACKET_MAX_SIZE)
1626 return SSH_ERR_INTERNAL_ERROR;
1627 return ssh_packet_start_discard(ssh, enc, mac,
1628 sshbuf_len(state->incoming_packet),
1629 PACKET_MAX_SIZE - need - block_size);
1630 }
1631 /* Remove MAC from input buffer */
1632 DBG(debug("MAC #%d ok", state->p_read.seqnr));
1633 if ((r = sshbuf_consume(state->input, mac->mac_len)) != 0)
1634 goto out;
1635 }
1636 if (seqnr_p != NULL)
1637 *seqnr_p = state->p_read.seqnr;
1638 if (++state->p_read.seqnr == 0)
1639 logit("incoming seqnr wraps around");
1640 if (++state->p_read.packets == 0)
1641 if (!(ssh->compat & SSH_BUG_NOREKEY))
1642 return SSH_ERR_NEED_REKEY;
1643 state->p_read.blocks += (state->packlen + 4) / block_size;
1644 state->p_read.bytes += state->packlen + 4;
1645
1646 /* get padlen */
1647 padlen = sshbuf_ptr(state->incoming_packet)[4];
1648 DBG(debug("input: padlen %d", padlen));
1649 if (padlen < 4) {
1650 if ((r = sshpkt_disconnect(ssh,
1651 "Corrupted padlen %d on input.", padlen)) != 0 ||
1652 (r = ssh_packet_write_wait(ssh)) != 0)
1653 return r;
1654 return SSH_ERR_CONN_CORRUPT;
1655 }
1656
1657 /* skip packet size + padlen, discard padding */
1658 if ((r = sshbuf_consume(state->incoming_packet, 4 + 1)) != 0 ||
1659 ((r = sshbuf_consume_end(state->incoming_packet, padlen)) != 0))
1660 goto out;
1661
1662 DBG(debug("input: len before de-compress %zd",
1663 sshbuf_len(state->incoming_packet)));
1664 if (comp && comp->enabled) {
1665 sshbuf_reset(state->compression_buffer);
1666 if ((r = uncompress_buffer(ssh, state->incoming_packet,
1667 state->compression_buffer)) != 0)
1668 goto out;
1669 sshbuf_reset(state->incoming_packet);
1670 if ((r = sshbuf_putb(state->incoming_packet,
1671 state->compression_buffer)) != 0)
1672 goto out;
1673 DBG(debug("input: len after de-compress %zd",
1674 sshbuf_len(state->incoming_packet)));
1675 }
1676 /*
1677 * get packet type, implies consume.
1678 * return length of payload (without type field)
1679 */
1680 if ((r = sshbuf_get_u8(state->incoming_packet, typep)) != 0)
1681 goto out;
1682 if (ssh_packet_log_type(*typep))
1683 debug3("receive packet: type %u", *typep);
1684 if (*typep < SSH2_MSG_MIN || *typep >= SSH2_MSG_LOCAL_MIN) {
1685 if ((r = sshpkt_disconnect(ssh,
1686 "Invalid ssh2 packet type: %d", *typep)) != 0 ||
1687 (r = ssh_packet_write_wait(ssh)) != 0)
1688 return r;
1689 return SSH_ERR_PROTOCOL_ERROR;
1690 }
1691 if (state->hook_in != NULL &&
1692 (r = state->hook_in(ssh, state->incoming_packet, typep,
1693 state->hook_in_ctx)) != 0)
1694 return r;
1695 if (*typep == SSH2_MSG_USERAUTH_SUCCESS && !state->server_side)
1696 r = ssh_packet_enable_delayed_compress(ssh);
1697 else
1698 r = 0;
1699 #ifdef PACKET_DEBUG
1700 fprintf(stderr, "read/plain[%d]:\r\n", *typep);
1701 sshbuf_dump(state->incoming_packet, stderr);
1702 #endif
1703 /* reset for next packet */
1704 state->packlen = 0;
1705
1706 /* do we need to rekey? */
1707 if (ssh_packet_need_rekeying(ssh, 0)) {
1708 debug3("%s: rekex triggered", __func__);
1709 if ((r = kex_start_rekex(ssh)) != 0)
1710 return r;
1711 }
1712 out:
1713 return r;
1714 }
1715
1716 int
ssh_packet_read_poll_seqnr(struct ssh * ssh,u_char * typep,u_int32_t * seqnr_p)1717 ssh_packet_read_poll_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
1718 {
1719 struct session_state *state = ssh->state;
1720 u_int reason, seqnr;
1721 int r;
1722 u_char *msg;
1723
1724 for (;;) {
1725 msg = NULL;
1726 r = ssh_packet_read_poll2(ssh, typep, seqnr_p);
1727 if (r != 0)
1728 return r;
1729 if (*typep) {
1730 state->keep_alive_timeouts = 0;
1731 DBG(debug("received packet type %d", *typep));
1732 }
1733 switch (*typep) {
1734 case SSH2_MSG_IGNORE:
1735 debug3("Received SSH2_MSG_IGNORE");
1736 break;
1737 case SSH2_MSG_DEBUG:
1738 if ((r = sshpkt_get_u8(ssh, NULL)) != 0 ||
1739 (r = sshpkt_get_string(ssh, &msg, NULL)) != 0 ||
1740 (r = sshpkt_get_string(ssh, NULL, NULL)) != 0) {
1741 free(msg);
1742 return r;
1743 }
1744 debug("Remote: %.900s", msg);
1745 free(msg);
1746 break;
1747 case SSH2_MSG_DISCONNECT:
1748 if ((r = sshpkt_get_u32(ssh, &reason)) != 0 ||
1749 (r = sshpkt_get_string(ssh, &msg, NULL)) != 0)
1750 return r;
1751 /* Ignore normal client exit notifications */
1752 do_log2(ssh->state->server_side &&
1753 reason == SSH2_DISCONNECT_BY_APPLICATION ?
1754 SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_ERROR,
1755 "Received disconnect from %s port %d:"
1756 "%u: %.400s", ssh_remote_ipaddr(ssh),
1757 ssh_remote_port(ssh), reason, msg);
1758 free(msg);
1759 return SSH_ERR_DISCONNECTED;
1760 case SSH2_MSG_UNIMPLEMENTED:
1761 if ((r = sshpkt_get_u32(ssh, &seqnr)) != 0)
1762 return r;
1763 debug("Received SSH2_MSG_UNIMPLEMENTED for %u",
1764 seqnr);
1765 break;
1766 default:
1767 return 0;
1768 }
1769 }
1770 }
1771
1772 /*
1773 * Buffers the given amount of input characters. This is intended to be used
1774 * together with packet_read_poll.
1775 */
1776
1777 int
ssh_packet_process_incoming(struct ssh * ssh,const char * buf,u_int len)1778 ssh_packet_process_incoming(struct ssh *ssh, const char *buf, u_int len)
1779 {
1780 struct session_state *state = ssh->state;
1781 int r;
1782
1783 if (state->packet_discard) {
1784 state->keep_alive_timeouts = 0; /* ?? */
1785 if (len >= state->packet_discard) {
1786 if ((r = ssh_packet_stop_discard(ssh)) != 0)
1787 return r;
1788 }
1789 state->packet_discard -= len;
1790 return 0;
1791 }
1792 if ((r = sshbuf_put(ssh->state->input, buf, len)) != 0)
1793 return r;
1794
1795 return 0;
1796 }
1797
1798 int
ssh_packet_remaining(struct ssh * ssh)1799 ssh_packet_remaining(struct ssh *ssh)
1800 {
1801 return sshbuf_len(ssh->state->incoming_packet);
1802 }
1803
1804 /*
1805 * Sends a diagnostic message from the server to the client. This message
1806 * can be sent at any time (but not while constructing another message). The
1807 * message is printed immediately, but only if the client is being executed
1808 * in verbose mode. These messages are primarily intended to ease debugging
1809 * authentication problems. The length of the formatted message must not
1810 * exceed 1024 bytes. This will automatically call ssh_packet_write_wait.
1811 */
1812 void
ssh_packet_send_debug(struct ssh * ssh,const char * fmt,...)1813 ssh_packet_send_debug(struct ssh *ssh, const char *fmt,...)
1814 {
1815 char buf[1024];
1816 va_list args;
1817 int r;
1818
1819 if ((ssh->compat & SSH_BUG_DEBUG))
1820 return;
1821
1822 va_start(args, fmt);
1823 vsnprintf(buf, sizeof(buf), fmt, args);
1824 va_end(args);
1825
1826 debug3("sending debug message: %s", buf);
1827
1828 if ((r = sshpkt_start(ssh, SSH2_MSG_DEBUG)) != 0 ||
1829 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* always display */
1830 (r = sshpkt_put_cstring(ssh, buf)) != 0 ||
1831 (r = sshpkt_put_cstring(ssh, "")) != 0 ||
1832 (r = sshpkt_send(ssh)) != 0 ||
1833 (r = ssh_packet_write_wait(ssh)) != 0)
1834 fatal("%s: %s", __func__, ssh_err(r));
1835 }
1836
1837 void
sshpkt_fmt_connection_id(struct ssh * ssh,char * s,size_t l)1838 sshpkt_fmt_connection_id(struct ssh *ssh, char *s, size_t l)
1839 {
1840 snprintf(s, l, "%.200s%s%s port %d",
1841 ssh->log_preamble ? ssh->log_preamble : "",
1842 ssh->log_preamble ? " " : "",
1843 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
1844 }
1845
1846 /*
1847 * Pretty-print connection-terminating errors and exit.
1848 */
1849 static void
sshpkt_vfatal(struct ssh * ssh,int r,const char * fmt,va_list ap)1850 sshpkt_vfatal(struct ssh *ssh, int r, const char *fmt, va_list ap)
1851 {
1852 char *tag = NULL, remote_id[512];
1853 int oerrno = errno;
1854
1855 sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id));
1856
1857 switch (r) {
1858 case SSH_ERR_CONN_CLOSED:
1859 ssh_packet_clear_keys(ssh);
1860 logdie("Connection closed by %s", remote_id);
1861 case SSH_ERR_CONN_TIMEOUT:
1862 ssh_packet_clear_keys(ssh);
1863 logdie("Connection %s %s timed out",
1864 ssh->state->server_side ? "from" : "to", remote_id);
1865 case SSH_ERR_DISCONNECTED:
1866 ssh_packet_clear_keys(ssh);
1867 logdie("Disconnected from %s", remote_id);
1868 case SSH_ERR_SYSTEM_ERROR:
1869 if (errno == ECONNRESET) {
1870 ssh_packet_clear_keys(ssh);
1871 logdie("Connection reset by %s", remote_id);
1872 }
1873 /* FALLTHROUGH */
1874 case SSH_ERR_NO_CIPHER_ALG_MATCH:
1875 case SSH_ERR_NO_MAC_ALG_MATCH:
1876 case SSH_ERR_NO_COMPRESS_ALG_MATCH:
1877 case SSH_ERR_NO_KEX_ALG_MATCH:
1878 case SSH_ERR_NO_HOSTKEY_ALG_MATCH:
1879 if (ssh && ssh->kex && ssh->kex->failed_choice) {
1880 ssh_packet_clear_keys(ssh);
1881 errno = oerrno;
1882 logdie("Unable to negotiate with %s: %s. "
1883 "Their offer: %s", remote_id, ssh_err(r),
1884 ssh->kex->failed_choice);
1885 }
1886 /* FALLTHROUGH */
1887 default:
1888 if (vasprintf(&tag, fmt, ap) == -1) {
1889 ssh_packet_clear_keys(ssh);
1890 logdie("%s: could not allocate failure message",
1891 __func__);
1892 }
1893 ssh_packet_clear_keys(ssh);
1894 errno = oerrno;
1895 logdie("%s%sConnection %s %s: %s",
1896 tag != NULL ? tag : "", tag != NULL ? ": " : "",
1897 ssh->state->server_side ? "from" : "to",
1898 remote_id, ssh_err(r));
1899 }
1900 }
1901
1902 void
sshpkt_fatal(struct ssh * ssh,int r,const char * fmt,...)1903 sshpkt_fatal(struct ssh *ssh, int r, const char *fmt, ...)
1904 {
1905 va_list ap;
1906
1907 va_start(ap, fmt);
1908 sshpkt_vfatal(ssh, r, fmt, ap);
1909 /* NOTREACHED */
1910 va_end(ap);
1911 logdie("%s: should have exited", __func__);
1912 }
1913
1914 /*
1915 * Logs the error plus constructs and sends a disconnect packet, closes the
1916 * connection, and exits. This function never returns. The error message
1917 * should not contain a newline. The length of the formatted message must
1918 * not exceed 1024 bytes.
1919 */
1920 void
ssh_packet_disconnect(struct ssh * ssh,const char * fmt,...)1921 ssh_packet_disconnect(struct ssh *ssh, const char *fmt,...)
1922 {
1923 char buf[1024], remote_id[512];
1924 va_list args;
1925 static int disconnecting = 0;
1926 int r;
1927
1928 if (disconnecting) /* Guard against recursive invocations. */
1929 fatal("packet_disconnect called recursively.");
1930 disconnecting = 1;
1931
1932 /*
1933 * Format the message. Note that the caller must make sure the
1934 * message is of limited size.
1935 */
1936 sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id));
1937 va_start(args, fmt);
1938 vsnprintf(buf, sizeof(buf), fmt, args);
1939 va_end(args);
1940
1941 /* Display the error locally */
1942 logit("Disconnecting %s: %.100s", remote_id, buf);
1943
1944 /*
1945 * Send the disconnect message to the other side, and wait
1946 * for it to get sent.
1947 */
1948 if ((r = sshpkt_disconnect(ssh, "%s", buf)) != 0)
1949 sshpkt_fatal(ssh, r, "%s", __func__);
1950
1951 if ((r = ssh_packet_write_wait(ssh)) != 0)
1952 sshpkt_fatal(ssh, r, "%s", __func__);
1953
1954 /* Close the connection. */
1955 ssh_packet_close(ssh);
1956 cleanup_exit(255);
1957 }
1958
1959 /*
1960 * Checks if there is any buffered output, and tries to write some of
1961 * the output.
1962 */
1963 int
ssh_packet_write_poll(struct ssh * ssh)1964 ssh_packet_write_poll(struct ssh *ssh)
1965 {
1966 struct session_state *state = ssh->state;
1967 int len = sshbuf_len(state->output);
1968 int r;
1969
1970 if (len > 0) {
1971 len = write(state->connection_out,
1972 sshbuf_ptr(state->output), len);
1973 if (len == -1) {
1974 if (errno == EINTR || errno == EAGAIN ||
1975 errno == EWOULDBLOCK)
1976 return 0;
1977 return SSH_ERR_SYSTEM_ERROR;
1978 }
1979 if (len == 0)
1980 return SSH_ERR_CONN_CLOSED;
1981 if ((r = sshbuf_consume(state->output, len)) != 0)
1982 return r;
1983 }
1984 return 0;
1985 }
1986
1987 /*
1988 * Calls packet_write_poll repeatedly until all pending output data has been
1989 * written.
1990 */
1991 int
ssh_packet_write_wait(struct ssh * ssh)1992 ssh_packet_write_wait(struct ssh *ssh)
1993 {
1994 fd_set *setp;
1995 int ret, r, ms_remain = 0;
1996 struct timeval start, timeout, *timeoutp = NULL;
1997 struct session_state *state = ssh->state;
1998
1999 setp = calloc(howmany(state->connection_out + 1,
2000 NFDBITS), sizeof(fd_mask));
2001 if (setp == NULL)
2002 return SSH_ERR_ALLOC_FAIL;
2003 if ((r = ssh_packet_write_poll(ssh)) != 0) {
2004 free(setp);
2005 return r;
2006 }
2007 while (ssh_packet_have_data_to_write(ssh)) {
2008 memset(setp, 0, howmany(state->connection_out + 1,
2009 NFDBITS) * sizeof(fd_mask));
2010 FD_SET(state->connection_out, setp);
2011
2012 if (state->packet_timeout_ms > 0) {
2013 ms_remain = state->packet_timeout_ms;
2014 timeoutp = &timeout;
2015 }
2016 for (;;) {
2017 if (state->packet_timeout_ms > 0) {
2018 ms_to_timeval(&timeout, ms_remain);
2019 monotime_tv(&start);
2020 }
2021 if ((ret = select(state->connection_out + 1,
2022 NULL, setp, NULL, timeoutp)) >= 0)
2023 break;
2024 if (errno != EAGAIN && errno != EINTR &&
2025 errno != EWOULDBLOCK)
2026 break;
2027 if (state->packet_timeout_ms <= 0)
2028 continue;
2029 ms_subtract_diff(&start, &ms_remain);
2030 if (ms_remain <= 0) {
2031 ret = 0;
2032 break;
2033 }
2034 }
2035 if (ret == 0) {
2036 free(setp);
2037 return SSH_ERR_CONN_TIMEOUT;
2038 }
2039 if ((r = ssh_packet_write_poll(ssh)) != 0) {
2040 free(setp);
2041 return r;
2042 }
2043 }
2044 free(setp);
2045 return 0;
2046 }
2047
2048 /* Returns true if there is buffered data to write to the connection. */
2049
2050 int
ssh_packet_have_data_to_write(struct ssh * ssh)2051 ssh_packet_have_data_to_write(struct ssh *ssh)
2052 {
2053 return sshbuf_len(ssh->state->output) != 0;
2054 }
2055
2056 /* Returns true if there is not too much data to write to the connection. */
2057
2058 int
ssh_packet_not_very_much_data_to_write(struct ssh * ssh)2059 ssh_packet_not_very_much_data_to_write(struct ssh *ssh)
2060 {
2061 if (ssh->state->interactive_mode)
2062 return sshbuf_len(ssh->state->output) < 16384;
2063 else
2064 return sshbuf_len(ssh->state->output) < 128 * 1024;
2065 }
2066
2067 void
ssh_packet_set_tos(struct ssh * ssh,int tos)2068 ssh_packet_set_tos(struct ssh *ssh, int tos)
2069 {
2070 #ifndef IP_TOS_IS_BROKEN
2071 if (!ssh_packet_connection_is_on_socket(ssh) || tos == INT_MAX)
2072 return;
2073 switch (ssh_packet_connection_af(ssh)) {
2074 # ifdef IP_TOS
2075 case AF_INET:
2076 debug3("%s: set IP_TOS 0x%02x", __func__, tos);
2077 if (setsockopt(ssh->state->connection_in,
2078 IPPROTO_IP, IP_TOS, &tos, sizeof(tos)) == -1)
2079 error("setsockopt IP_TOS %d: %.100s:",
2080 tos, strerror(errno));
2081 break;
2082 # endif /* IP_TOS */
2083 # ifdef IPV6_TCLASS
2084 case AF_INET6:
2085 debug3("%s: set IPV6_TCLASS 0x%02x", __func__, tos);
2086 if (setsockopt(ssh->state->connection_in,
2087 IPPROTO_IPV6, IPV6_TCLASS, &tos, sizeof(tos)) == -1)
2088 error("setsockopt IPV6_TCLASS %d: %.100s:",
2089 tos, strerror(errno));
2090 break;
2091 # endif /* IPV6_TCLASS */
2092 }
2093 #endif /* IP_TOS_IS_BROKEN */
2094 }
2095
2096 /* Informs that the current session is interactive. Sets IP flags for that. */
2097
2098 void
ssh_packet_set_interactive(struct ssh * ssh,int interactive,int qos_interactive,int qos_bulk)2099 ssh_packet_set_interactive(struct ssh *ssh, int interactive, int qos_interactive, int qos_bulk)
2100 {
2101 struct session_state *state = ssh->state;
2102
2103 if (state->set_interactive_called)
2104 return;
2105 state->set_interactive_called = 1;
2106
2107 /* Record that we are in interactive mode. */
2108 state->interactive_mode = interactive;
2109
2110 /* Only set socket options if using a socket. */
2111 if (!ssh_packet_connection_is_on_socket(ssh))
2112 return;
2113 set_nodelay(state->connection_in);
2114 ssh_packet_set_tos(ssh, interactive ? qos_interactive :
2115 qos_bulk);
2116 }
2117
2118 /* Returns true if the current connection is interactive. */
2119
2120 int
ssh_packet_is_interactive(struct ssh * ssh)2121 ssh_packet_is_interactive(struct ssh *ssh)
2122 {
2123 return ssh->state->interactive_mode;
2124 }
2125
2126 int
ssh_packet_set_maxsize(struct ssh * ssh,u_int s)2127 ssh_packet_set_maxsize(struct ssh *ssh, u_int s)
2128 {
2129 struct session_state *state = ssh->state;
2130
2131 if (state->set_maxsize_called) {
2132 logit("packet_set_maxsize: called twice: old %d new %d",
2133 state->max_packet_size, s);
2134 return -1;
2135 }
2136 if (s < 4 * 1024 || s > 1024 * 1024) {
2137 logit("packet_set_maxsize: bad size %d", s);
2138 return -1;
2139 }
2140 state->set_maxsize_called = 1;
2141 debug("packet_set_maxsize: setting to %d", s);
2142 state->max_packet_size = s;
2143 return s;
2144 }
2145
2146 int
ssh_packet_inc_alive_timeouts(struct ssh * ssh)2147 ssh_packet_inc_alive_timeouts(struct ssh *ssh)
2148 {
2149 return ++ssh->state->keep_alive_timeouts;
2150 }
2151
2152 void
ssh_packet_set_alive_timeouts(struct ssh * ssh,int ka)2153 ssh_packet_set_alive_timeouts(struct ssh *ssh, int ka)
2154 {
2155 ssh->state->keep_alive_timeouts = ka;
2156 }
2157
2158 u_int
ssh_packet_get_maxsize(struct ssh * ssh)2159 ssh_packet_get_maxsize(struct ssh *ssh)
2160 {
2161 return ssh->state->max_packet_size;
2162 }
2163
2164 void
ssh_packet_set_rekey_limits(struct ssh * ssh,u_int64_t bytes,u_int32_t seconds)2165 ssh_packet_set_rekey_limits(struct ssh *ssh, u_int64_t bytes, u_int32_t seconds)
2166 {
2167 debug3("rekey after %llu bytes, %u seconds", (unsigned long long)bytes,
2168 (unsigned int)seconds);
2169 ssh->state->rekey_limit = bytes;
2170 ssh->state->rekey_interval = seconds;
2171 }
2172
2173 time_t
ssh_packet_get_rekey_timeout(struct ssh * ssh)2174 ssh_packet_get_rekey_timeout(struct ssh *ssh)
2175 {
2176 time_t seconds;
2177
2178 seconds = ssh->state->rekey_time + ssh->state->rekey_interval -
2179 monotime();
2180 return (seconds <= 0 ? 1 : seconds);
2181 }
2182
2183 void
ssh_packet_set_server(struct ssh * ssh)2184 ssh_packet_set_server(struct ssh *ssh)
2185 {
2186 ssh->state->server_side = 1;
2187 ssh->kex->server = 1; /* XXX unify? */
2188 }
2189
2190 void
ssh_packet_set_authenticated(struct ssh * ssh)2191 ssh_packet_set_authenticated(struct ssh *ssh)
2192 {
2193 ssh->state->after_authentication = 1;
2194 }
2195
2196 void *
ssh_packet_get_input(struct ssh * ssh)2197 ssh_packet_get_input(struct ssh *ssh)
2198 {
2199 return (void *)ssh->state->input;
2200 }
2201
2202 void *
ssh_packet_get_output(struct ssh * ssh)2203 ssh_packet_get_output(struct ssh *ssh)
2204 {
2205 return (void *)ssh->state->output;
2206 }
2207
2208 /* Reset after_authentication and reset compression in post-auth privsep */
2209 static int
ssh_packet_set_postauth(struct ssh * ssh)2210 ssh_packet_set_postauth(struct ssh *ssh)
2211 {
2212 int r;
2213
2214 debug("%s: called", __func__);
2215 /* This was set in net child, but is not visible in user child */
2216 ssh->state->after_authentication = 1;
2217 ssh->state->rekeying = 0;
2218 if ((r = ssh_packet_enable_delayed_compress(ssh)) != 0)
2219 return r;
2220 return 0;
2221 }
2222
2223 /* Packet state (de-)serialization for privsep */
2224
2225 /* turn kex into a blob for packet state serialization */
2226 static int
kex_to_blob(struct sshbuf * m,struct kex * kex)2227 kex_to_blob(struct sshbuf *m, struct kex *kex)
2228 {
2229 int r;
2230
2231 if ((r = sshbuf_put_string(m, kex->session_id,
2232 kex->session_id_len)) != 0 ||
2233 (r = sshbuf_put_u32(m, kex->we_need)) != 0 ||
2234 (r = sshbuf_put_cstring(m, kex->hostkey_alg)) != 0 ||
2235 (r = sshbuf_put_u32(m, kex->hostkey_type)) != 0 ||
2236 (r = sshbuf_put_u32(m, kex->hostkey_nid)) != 0 ||
2237 (r = sshbuf_put_u32(m, kex->kex_type)) != 0 ||
2238 (r = sshbuf_put_stringb(m, kex->my)) != 0 ||
2239 (r = sshbuf_put_stringb(m, kex->peer)) != 0 ||
2240 (r = sshbuf_put_stringb(m, kex->client_version)) != 0 ||
2241 (r = sshbuf_put_stringb(m, kex->server_version)) != 0 ||
2242 (r = sshbuf_put_u32(m, kex->flags)) != 0)
2243 return r;
2244 return 0;
2245 }
2246
2247 /* turn key exchange results into a blob for packet state serialization */
2248 static int
newkeys_to_blob(struct sshbuf * m,struct ssh * ssh,int mode)2249 newkeys_to_blob(struct sshbuf *m, struct ssh *ssh, int mode)
2250 {
2251 struct sshbuf *b;
2252 struct sshcipher_ctx *cc;
2253 struct sshcomp *comp;
2254 struct sshenc *enc;
2255 struct sshmac *mac;
2256 struct newkeys *newkey;
2257 int r;
2258
2259 if ((newkey = ssh->state->newkeys[mode]) == NULL)
2260 return SSH_ERR_INTERNAL_ERROR;
2261 enc = &newkey->enc;
2262 mac = &newkey->mac;
2263 comp = &newkey->comp;
2264 cc = (mode == MODE_OUT) ? ssh->state->send_context :
2265 ssh->state->receive_context;
2266 if ((r = cipher_get_keyiv(cc, enc->iv, enc->iv_len)) != 0)
2267 return r;
2268 if ((b = sshbuf_new()) == NULL)
2269 return SSH_ERR_ALLOC_FAIL;
2270 if ((r = sshbuf_put_cstring(b, enc->name)) != 0 ||
2271 (r = sshbuf_put_u32(b, enc->enabled)) != 0 ||
2272 (r = sshbuf_put_u32(b, enc->block_size)) != 0 ||
2273 (r = sshbuf_put_string(b, enc->key, enc->key_len)) != 0 ||
2274 (r = sshbuf_put_string(b, enc->iv, enc->iv_len)) != 0)
2275 goto out;
2276 if (cipher_authlen(enc->cipher) == 0) {
2277 if ((r = sshbuf_put_cstring(b, mac->name)) != 0 ||
2278 (r = sshbuf_put_u32(b, mac->enabled)) != 0 ||
2279 (r = sshbuf_put_string(b, mac->key, mac->key_len)) != 0)
2280 goto out;
2281 }
2282 if ((r = sshbuf_put_u32(b, comp->type)) != 0 ||
2283 (r = sshbuf_put_cstring(b, comp->name)) != 0)
2284 goto out;
2285 r = sshbuf_put_stringb(m, b);
2286 out:
2287 sshbuf_free(b);
2288 return r;
2289 }
2290
2291 /* serialize packet state into a blob */
2292 int
ssh_packet_get_state(struct ssh * ssh,struct sshbuf * m)2293 ssh_packet_get_state(struct ssh *ssh, struct sshbuf *m)
2294 {
2295 struct session_state *state = ssh->state;
2296 int r;
2297
2298 if ((r = kex_to_blob(m, ssh->kex)) != 0 ||
2299 (r = newkeys_to_blob(m, ssh, MODE_OUT)) != 0 ||
2300 (r = newkeys_to_blob(m, ssh, MODE_IN)) != 0 ||
2301 (r = sshbuf_put_u64(m, state->rekey_limit)) != 0 ||
2302 (r = sshbuf_put_u32(m, state->rekey_interval)) != 0 ||
2303 (r = sshbuf_put_u32(m, state->p_send.seqnr)) != 0 ||
2304 (r = sshbuf_put_u64(m, state->p_send.blocks)) != 0 ||
2305 (r = sshbuf_put_u32(m, state->p_send.packets)) != 0 ||
2306 (r = sshbuf_put_u64(m, state->p_send.bytes)) != 0 ||
2307 (r = sshbuf_put_u32(m, state->p_read.seqnr)) != 0 ||
2308 (r = sshbuf_put_u64(m, state->p_read.blocks)) != 0 ||
2309 (r = sshbuf_put_u32(m, state->p_read.packets)) != 0 ||
2310 (r = sshbuf_put_u64(m, state->p_read.bytes)) != 0 ||
2311 (r = sshbuf_put_stringb(m, state->input)) != 0 ||
2312 (r = sshbuf_put_stringb(m, state->output)) != 0)
2313 return r;
2314
2315 return 0;
2316 }
2317
2318 /* restore key exchange results from blob for packet state de-serialization */
2319 static int
newkeys_from_blob(struct sshbuf * m,struct ssh * ssh,int mode)2320 newkeys_from_blob(struct sshbuf *m, struct ssh *ssh, int mode)
2321 {
2322 struct sshbuf *b = NULL;
2323 struct sshcomp *comp;
2324 struct sshenc *enc;
2325 struct sshmac *mac;
2326 struct newkeys *newkey = NULL;
2327 size_t keylen, ivlen, maclen;
2328 int r;
2329
2330 if ((newkey = calloc(1, sizeof(*newkey))) == NULL) {
2331 r = SSH_ERR_ALLOC_FAIL;
2332 goto out;
2333 }
2334 if ((r = sshbuf_froms(m, &b)) != 0)
2335 goto out;
2336 #ifdef DEBUG_PK
2337 sshbuf_dump(b, stderr);
2338 #endif
2339 enc = &newkey->enc;
2340 mac = &newkey->mac;
2341 comp = &newkey->comp;
2342
2343 if ((r = sshbuf_get_cstring(b, &enc->name, NULL)) != 0 ||
2344 (r = sshbuf_get_u32(b, (u_int *)&enc->enabled)) != 0 ||
2345 (r = sshbuf_get_u32(b, &enc->block_size)) != 0 ||
2346 (r = sshbuf_get_string(b, &enc->key, &keylen)) != 0 ||
2347 (r = sshbuf_get_string(b, &enc->iv, &ivlen)) != 0)
2348 goto out;
2349 if ((enc->cipher = cipher_by_name(enc->name)) == NULL) {
2350 r = SSH_ERR_INVALID_FORMAT;
2351 goto out;
2352 }
2353 if (cipher_authlen(enc->cipher) == 0) {
2354 if ((r = sshbuf_get_cstring(b, &mac->name, NULL)) != 0)
2355 goto out;
2356 if ((r = mac_setup(mac, mac->name)) != 0)
2357 goto out;
2358 if ((r = sshbuf_get_u32(b, (u_int *)&mac->enabled)) != 0 ||
2359 (r = sshbuf_get_string(b, &mac->key, &maclen)) != 0)
2360 goto out;
2361 if (maclen > mac->key_len) {
2362 r = SSH_ERR_INVALID_FORMAT;
2363 goto out;
2364 }
2365 mac->key_len = maclen;
2366 }
2367 if ((r = sshbuf_get_u32(b, &comp->type)) != 0 ||
2368 (r = sshbuf_get_cstring(b, &comp->name, NULL)) != 0)
2369 goto out;
2370 if (sshbuf_len(b) != 0) {
2371 r = SSH_ERR_INVALID_FORMAT;
2372 goto out;
2373 }
2374 enc->key_len = keylen;
2375 enc->iv_len = ivlen;
2376 ssh->kex->newkeys[mode] = newkey;
2377 newkey = NULL;
2378 r = 0;
2379 out:
2380 free(newkey);
2381 sshbuf_free(b);
2382 return r;
2383 }
2384
2385 /* restore kex from blob for packet state de-serialization */
2386 static int
kex_from_blob(struct sshbuf * m,struct kex ** kexp)2387 kex_from_blob(struct sshbuf *m, struct kex **kexp)
2388 {
2389 struct kex *kex;
2390 int r;
2391
2392 if ((kex = kex_new()) == NULL)
2393 return SSH_ERR_ALLOC_FAIL;
2394 if ((r = sshbuf_get_string(m, &kex->session_id, &kex->session_id_len)) != 0 ||
2395 (r = sshbuf_get_u32(m, &kex->we_need)) != 0 ||
2396 (r = sshbuf_get_cstring(m, &kex->hostkey_alg, NULL)) != 0 ||
2397 (r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_type)) != 0 ||
2398 (r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_nid)) != 0 ||
2399 (r = sshbuf_get_u32(m, &kex->kex_type)) != 0 ||
2400 (r = sshbuf_get_stringb(m, kex->my)) != 0 ||
2401 (r = sshbuf_get_stringb(m, kex->peer)) != 0 ||
2402 (r = sshbuf_get_stringb(m, kex->client_version)) != 0 ||
2403 (r = sshbuf_get_stringb(m, kex->server_version)) != 0 ||
2404 (r = sshbuf_get_u32(m, &kex->flags)) != 0)
2405 goto out;
2406 kex->server = 1;
2407 kex->done = 1;
2408 r = 0;
2409 out:
2410 if (r != 0 || kexp == NULL) {
2411 kex_free(kex);
2412 if (kexp != NULL)
2413 *kexp = NULL;
2414 } else {
2415 kex_free(*kexp);
2416 *kexp = kex;
2417 }
2418 return r;
2419 }
2420
2421 /*
2422 * Restore packet state from content of blob 'm' (de-serialization).
2423 * Note that 'm' will be partially consumed on parsing or any other errors.
2424 */
2425 int
ssh_packet_set_state(struct ssh * ssh,struct sshbuf * m)2426 ssh_packet_set_state(struct ssh *ssh, struct sshbuf *m)
2427 {
2428 struct session_state *state = ssh->state;
2429 const u_char *input, *output;
2430 size_t ilen, olen;
2431 int r;
2432
2433 if ((r = kex_from_blob(m, &ssh->kex)) != 0 ||
2434 (r = newkeys_from_blob(m, ssh, MODE_OUT)) != 0 ||
2435 (r = newkeys_from_blob(m, ssh, MODE_IN)) != 0 ||
2436 (r = sshbuf_get_u64(m, &state->rekey_limit)) != 0 ||
2437 (r = sshbuf_get_u32(m, &state->rekey_interval)) != 0 ||
2438 (r = sshbuf_get_u32(m, &state->p_send.seqnr)) != 0 ||
2439 (r = sshbuf_get_u64(m, &state->p_send.blocks)) != 0 ||
2440 (r = sshbuf_get_u32(m, &state->p_send.packets)) != 0 ||
2441 (r = sshbuf_get_u64(m, &state->p_send.bytes)) != 0 ||
2442 (r = sshbuf_get_u32(m, &state->p_read.seqnr)) != 0 ||
2443 (r = sshbuf_get_u64(m, &state->p_read.blocks)) != 0 ||
2444 (r = sshbuf_get_u32(m, &state->p_read.packets)) != 0 ||
2445 (r = sshbuf_get_u64(m, &state->p_read.bytes)) != 0)
2446 return r;
2447 /*
2448 * We set the time here so that in post-auth privsep slave we
2449 * count from the completion of the authentication.
2450 */
2451 state->rekey_time = monotime();
2452 /* XXX ssh_set_newkeys overrides p_read.packets? XXX */
2453 if ((r = ssh_set_newkeys(ssh, MODE_IN)) != 0 ||
2454 (r = ssh_set_newkeys(ssh, MODE_OUT)) != 0)
2455 return r;
2456
2457 if ((r = ssh_packet_set_postauth(ssh)) != 0)
2458 return r;
2459
2460 sshbuf_reset(state->input);
2461 sshbuf_reset(state->output);
2462 if ((r = sshbuf_get_string_direct(m, &input, &ilen)) != 0 ||
2463 (r = sshbuf_get_string_direct(m, &output, &olen)) != 0 ||
2464 (r = sshbuf_put(state->input, input, ilen)) != 0 ||
2465 (r = sshbuf_put(state->output, output, olen)) != 0)
2466 return r;
2467
2468 if (sshbuf_len(m))
2469 return SSH_ERR_INVALID_FORMAT;
2470 debug3("%s: done", __func__);
2471 return 0;
2472 }
2473
2474 /* NEW API */
2475
2476 /* put data to the outgoing packet */
2477
2478 int
sshpkt_put(struct ssh * ssh,const void * v,size_t len)2479 sshpkt_put(struct ssh *ssh, const void *v, size_t len)
2480 {
2481 return sshbuf_put(ssh->state->outgoing_packet, v, len);
2482 }
2483
2484 int
sshpkt_putb(struct ssh * ssh,const struct sshbuf * b)2485 sshpkt_putb(struct ssh *ssh, const struct sshbuf *b)
2486 {
2487 return sshbuf_putb(ssh->state->outgoing_packet, b);
2488 }
2489
2490 int
sshpkt_put_u8(struct ssh * ssh,u_char val)2491 sshpkt_put_u8(struct ssh *ssh, u_char val)
2492 {
2493 return sshbuf_put_u8(ssh->state->outgoing_packet, val);
2494 }
2495
2496 int
sshpkt_put_u32(struct ssh * ssh,u_int32_t val)2497 sshpkt_put_u32(struct ssh *ssh, u_int32_t val)
2498 {
2499 return sshbuf_put_u32(ssh->state->outgoing_packet, val);
2500 }
2501
2502 int
sshpkt_put_u64(struct ssh * ssh,u_int64_t val)2503 sshpkt_put_u64(struct ssh *ssh, u_int64_t val)
2504 {
2505 return sshbuf_put_u64(ssh->state->outgoing_packet, val);
2506 }
2507
2508 int
sshpkt_put_string(struct ssh * ssh,const void * v,size_t len)2509 sshpkt_put_string(struct ssh *ssh, const void *v, size_t len)
2510 {
2511 return sshbuf_put_string(ssh->state->outgoing_packet, v, len);
2512 }
2513
2514 int
sshpkt_put_cstring(struct ssh * ssh,const void * v)2515 sshpkt_put_cstring(struct ssh *ssh, const void *v)
2516 {
2517 return sshbuf_put_cstring(ssh->state->outgoing_packet, v);
2518 }
2519
2520 int
sshpkt_put_stringb(struct ssh * ssh,const struct sshbuf * v)2521 sshpkt_put_stringb(struct ssh *ssh, const struct sshbuf *v)
2522 {
2523 return sshbuf_put_stringb(ssh->state->outgoing_packet, v);
2524 }
2525
2526 int
sshpkt_getb_froms(struct ssh * ssh,struct sshbuf ** valp)2527 sshpkt_getb_froms(struct ssh *ssh, struct sshbuf **valp)
2528 {
2529 return sshbuf_froms(ssh->state->incoming_packet, valp);
2530 }
2531
2532 #ifdef WITH_OPENSSL
2533 #ifdef OPENSSL_HAS_ECC
2534 int
sshpkt_put_ec(struct ssh * ssh,const EC_POINT * v,const EC_GROUP * g)2535 sshpkt_put_ec(struct ssh *ssh, const EC_POINT *v, const EC_GROUP *g)
2536 {
2537 return sshbuf_put_ec(ssh->state->outgoing_packet, v, g);
2538 }
2539 #endif /* OPENSSL_HAS_ECC */
2540
2541
2542 int
sshpkt_put_bignum2(struct ssh * ssh,const BIGNUM * v)2543 sshpkt_put_bignum2(struct ssh *ssh, const BIGNUM *v)
2544 {
2545 return sshbuf_put_bignum2(ssh->state->outgoing_packet, v);
2546 }
2547 #endif /* WITH_OPENSSL */
2548
2549 /* fetch data from the incoming packet */
2550
2551 int
sshpkt_get(struct ssh * ssh,void * valp,size_t len)2552 sshpkt_get(struct ssh *ssh, void *valp, size_t len)
2553 {
2554 return sshbuf_get(ssh->state->incoming_packet, valp, len);
2555 }
2556
2557 int
sshpkt_get_u8(struct ssh * ssh,u_char * valp)2558 sshpkt_get_u8(struct ssh *ssh, u_char *valp)
2559 {
2560 return sshbuf_get_u8(ssh->state->incoming_packet, valp);
2561 }
2562
2563 int
sshpkt_get_u32(struct ssh * ssh,u_int32_t * valp)2564 sshpkt_get_u32(struct ssh *ssh, u_int32_t *valp)
2565 {
2566 return sshbuf_get_u32(ssh->state->incoming_packet, valp);
2567 }
2568
2569 int
sshpkt_get_u64(struct ssh * ssh,u_int64_t * valp)2570 sshpkt_get_u64(struct ssh *ssh, u_int64_t *valp)
2571 {
2572 return sshbuf_get_u64(ssh->state->incoming_packet, valp);
2573 }
2574
2575 int
sshpkt_get_string(struct ssh * ssh,u_char ** valp,size_t * lenp)2576 sshpkt_get_string(struct ssh *ssh, u_char **valp, size_t *lenp)
2577 {
2578 return sshbuf_get_string(ssh->state->incoming_packet, valp, lenp);
2579 }
2580
2581 int
sshpkt_get_string_direct(struct ssh * ssh,const u_char ** valp,size_t * lenp)2582 sshpkt_get_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp)
2583 {
2584 return sshbuf_get_string_direct(ssh->state->incoming_packet, valp, lenp);
2585 }
2586
2587 int
sshpkt_peek_string_direct(struct ssh * ssh,const u_char ** valp,size_t * lenp)2588 sshpkt_peek_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp)
2589 {
2590 return sshbuf_peek_string_direct(ssh->state->incoming_packet, valp, lenp);
2591 }
2592
2593 int
sshpkt_get_cstring(struct ssh * ssh,char ** valp,size_t * lenp)2594 sshpkt_get_cstring(struct ssh *ssh, char **valp, size_t *lenp)
2595 {
2596 return sshbuf_get_cstring(ssh->state->incoming_packet, valp, lenp);
2597 }
2598
2599 #ifdef WITH_OPENSSL
2600 #ifdef OPENSSL_HAS_ECC
2601 int
sshpkt_get_ec(struct ssh * ssh,EC_POINT * v,const EC_GROUP * g)2602 sshpkt_get_ec(struct ssh *ssh, EC_POINT *v, const EC_GROUP *g)
2603 {
2604 return sshbuf_get_ec(ssh->state->incoming_packet, v, g);
2605 }
2606 #endif /* OPENSSL_HAS_ECC */
2607
2608 int
sshpkt_get_bignum2(struct ssh * ssh,BIGNUM ** valp)2609 sshpkt_get_bignum2(struct ssh *ssh, BIGNUM **valp)
2610 {
2611 return sshbuf_get_bignum2(ssh->state->incoming_packet, valp);
2612 }
2613 #endif /* WITH_OPENSSL */
2614
2615 int
sshpkt_get_end(struct ssh * ssh)2616 sshpkt_get_end(struct ssh *ssh)
2617 {
2618 if (sshbuf_len(ssh->state->incoming_packet) > 0)
2619 return SSH_ERR_UNEXPECTED_TRAILING_DATA;
2620 return 0;
2621 }
2622
2623 const u_char *
sshpkt_ptr(struct ssh * ssh,size_t * lenp)2624 sshpkt_ptr(struct ssh *ssh, size_t *lenp)
2625 {
2626 if (lenp != NULL)
2627 *lenp = sshbuf_len(ssh->state->incoming_packet);
2628 return sshbuf_ptr(ssh->state->incoming_packet);
2629 }
2630
2631 /* start a new packet */
2632
2633 int
sshpkt_start(struct ssh * ssh,u_char type)2634 sshpkt_start(struct ssh *ssh, u_char type)
2635 {
2636 u_char buf[6]; /* u32 packet length, u8 pad len, u8 type */
2637
2638 DBG(debug("packet_start[%d]", type));
2639 memset(buf, 0, sizeof(buf));
2640 buf[sizeof(buf) - 1] = type;
2641 sshbuf_reset(ssh->state->outgoing_packet);
2642 return sshbuf_put(ssh->state->outgoing_packet, buf, sizeof(buf));
2643 }
2644
2645 static int
ssh_packet_send_mux(struct ssh * ssh)2646 ssh_packet_send_mux(struct ssh *ssh)
2647 {
2648 struct session_state *state = ssh->state;
2649 u_char type, *cp;
2650 size_t len;
2651 int r;
2652
2653 if (ssh->kex)
2654 return SSH_ERR_INTERNAL_ERROR;
2655 len = sshbuf_len(state->outgoing_packet);
2656 if (len < 6)
2657 return SSH_ERR_INTERNAL_ERROR;
2658 cp = sshbuf_mutable_ptr(state->outgoing_packet);
2659 type = cp[5];
2660 if (ssh_packet_log_type(type))
2661 debug3("%s: type %u", __func__, type);
2662 /* drop everything, but the connection protocol */
2663 if (type >= SSH2_MSG_CONNECTION_MIN &&
2664 type <= SSH2_MSG_CONNECTION_MAX) {
2665 POKE_U32(cp, len - 4);
2666 if ((r = sshbuf_putb(state->output,
2667 state->outgoing_packet)) != 0)
2668 return r;
2669 /* sshbuf_dump(state->output, stderr); */
2670 }
2671 sshbuf_reset(state->outgoing_packet);
2672 return 0;
2673 }
2674
2675 /*
2676 * 9.2. Ignored Data Message
2677 *
2678 * byte SSH_MSG_IGNORE
2679 * string data
2680 *
2681 * All implementations MUST understand (and ignore) this message at any
2682 * time (after receiving the protocol version). No implementation is
2683 * required to send them. This message can be used as an additional
2684 * protection measure against advanced traffic analysis techniques.
2685 */
2686 int
sshpkt_msg_ignore(struct ssh * ssh,u_int nbytes)2687 sshpkt_msg_ignore(struct ssh *ssh, u_int nbytes)
2688 {
2689 u_int32_t rnd = 0;
2690 int r;
2691 u_int i;
2692
2693 if ((r = sshpkt_start(ssh, SSH2_MSG_IGNORE)) != 0 ||
2694 (r = sshpkt_put_u32(ssh, nbytes)) != 0)
2695 return r;
2696 for (i = 0; i < nbytes; i++) {
2697 if (i % 4 == 0)
2698 rnd = arc4random();
2699 if ((r = sshpkt_put_u8(ssh, (u_char)rnd & 0xff)) != 0)
2700 return r;
2701 rnd >>= 8;
2702 }
2703 return 0;
2704 }
2705
2706 /* send it */
2707
2708 int
sshpkt_send(struct ssh * ssh)2709 sshpkt_send(struct ssh *ssh)
2710 {
2711 if (ssh->state && ssh->state->mux)
2712 return ssh_packet_send_mux(ssh);
2713 return ssh_packet_send2(ssh);
2714 }
2715
2716 int
sshpkt_disconnect(struct ssh * ssh,const char * fmt,...)2717 sshpkt_disconnect(struct ssh *ssh, const char *fmt,...)
2718 {
2719 char buf[1024];
2720 va_list args;
2721 int r;
2722
2723 va_start(args, fmt);
2724 vsnprintf(buf, sizeof(buf), fmt, args);
2725 va_end(args);
2726
2727 if ((r = sshpkt_start(ssh, SSH2_MSG_DISCONNECT)) != 0 ||
2728 (r = sshpkt_put_u32(ssh, SSH2_DISCONNECT_PROTOCOL_ERROR)) != 0 ||
2729 (r = sshpkt_put_cstring(ssh, buf)) != 0 ||
2730 (r = sshpkt_put_cstring(ssh, "")) != 0 ||
2731 (r = sshpkt_send(ssh)) != 0)
2732 return r;
2733 return 0;
2734 }
2735
2736 /* roundup current message to pad bytes */
2737 int
sshpkt_add_padding(struct ssh * ssh,u_char pad)2738 sshpkt_add_padding(struct ssh *ssh, u_char pad)
2739 {
2740 ssh->state->extra_pad = pad;
2741 return 0;
2742 }
2743