1 /* $NetBSD: packet.c,v 1.48 2023/07/26 17:58:15 christos Exp $ */
2 /* $OpenBSD: packet.c,v 1.309 2023/03/03 10:23:42 dtucker Exp $ */
3 /*
4 * Author: Tatu Ylonen <ylo@cs.hut.fi>
5 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
6 * All rights reserved
7 * This file contains code implementing the packet protocol and communication
8 * with the other side. This same code is used both on client and server side.
9 *
10 * As far as I am concerned, the code I have written for this software
11 * can be used freely for any purpose. Any derived versions of this
12 * software must be clearly marked as such, and if the derived work is
13 * incompatible with the protocol description in the RFC file, it must be
14 * called by a name other than "ssh" or "Secure Shell".
15 *
16 *
17 * SSH2 packet format added by Markus Friedl.
18 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
19 *
20 * Redistribution and use in source and binary forms, with or without
21 * modification, are permitted provided that the following conditions
22 * are met:
23 * 1. Redistributions of source code must retain the above copyright
24 * notice, this list of conditions and the following disclaimer.
25 * 2. Redistributions in binary form must reproduce the above copyright
26 * notice, this list of conditions and the following disclaimer in the
27 * documentation and/or other materials provided with the distribution.
28 *
29 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
30 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
31 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
32 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
33 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
34 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
35 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
36 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
37 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
38 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
39 */
40
41 #include "includes.h"
42 __RCSID("$NetBSD: packet.c,v 1.48 2023/07/26 17:58:15 christos Exp $");
43
44 #include <sys/param.h> /* MIN roundup */
45 #include <sys/types.h>
46 #include <sys/queue.h>
47 #include <sys/socket.h>
48 #include <sys/time.h>
49 #include <netinet/in.h>
50 #include <netinet/ip.h>
51
52 #include <errno.h>
53 #include <netdb.h>
54 #include <stdarg.h>
55 #include <stdio.h>
56 #include <stdlib.h>
57 #include <string.h>
58 #include <unistd.h>
59 #include <limits.h>
60 #include <poll.h>
61 #include <signal.h>
62 #include <time.h>
63
64 #ifdef WITH_ZLIB
65 #include <zlib.h>
66 #endif
67
68 #include "xmalloc.h"
69 #include "compat.h"
70 #include "ssh2.h"
71 #include "cipher.h"
72 #include "sshkey.h"
73 #include "kex.h"
74 #include "digest.h"
75 #include "mac.h"
76 #include "log.h"
77 #include "canohost.h"
78 #include "misc.h"
79 #include "channels.h"
80 #include "ssh.h"
81 #include "packet.h"
82 #include "ssherr.h"
83 #include "sshbuf.h"
84
85 #ifdef PACKET_DEBUG
86 #define DBG(x) x
87 #else
88 #define DBG(x)
89 #endif
90
91 #define PACKET_MAX_SIZE (256 * 1024)
92
93 struct packet_state {
94 u_int32_t seqnr;
95 u_int32_t packets;
96 u_int64_t blocks;
97 u_int64_t bytes;
98 };
99
100 struct packet {
101 TAILQ_ENTRY(packet) next;
102 u_char type;
103 struct sshbuf *payload;
104 };
105
106 struct session_state {
107 /*
108 * This variable contains the file descriptors used for
109 * communicating with the other side. connection_in is used for
110 * reading; connection_out for writing. These can be the same
111 * descriptor, in which case it is assumed to be a socket.
112 */
113 int connection_in;
114 int connection_out;
115
116 /* Protocol flags for the remote side. */
117 u_int remote_protocol_flags;
118
119 /* Encryption context for receiving data. Only used for decryption. */
120 struct sshcipher_ctx *receive_context;
121
122 /* Encryption context for sending data. Only used for encryption. */
123 struct sshcipher_ctx *send_context;
124
125 /* Buffer for raw input data from the socket. */
126 struct sshbuf *input;
127
128 /* Buffer for raw output data going to the socket. */
129 struct sshbuf *output;
130
131 /* Buffer for the partial outgoing packet being constructed. */
132 struct sshbuf *outgoing_packet;
133
134 /* Buffer for the incoming packet currently being processed. */
135 struct sshbuf *incoming_packet;
136
137 /* Scratch buffer for packet compression/decompression. */
138 struct sshbuf *compression_buffer;
139
140 #ifdef WITH_ZLIB
141 /* Incoming/outgoing compression dictionaries */
142 z_stream compression_in_stream;
143 z_stream compression_out_stream;
144 #endif
145 int compression_in_started;
146 int compression_out_started;
147 int compression_in_failures;
148 int compression_out_failures;
149
150 /* default maximum packet size */
151 u_int max_packet_size;
152
153 /* Flag indicating whether this module has been initialized. */
154 int initialized;
155
156 /* Set to true if the connection is interactive. */
157 int interactive_mode;
158
159 /* Set to true if we are the server side. */
160 int server_side;
161
162 /* Set to true if we are authenticated. */
163 int after_authentication;
164
165 int keep_alive_timeouts;
166
167 /* The maximum time that we will wait to send or receive a packet */
168 int packet_timeout_ms;
169
170 /* Session key information for Encryption and MAC */
171 struct newkeys *newkeys[MODE_MAX];
172 struct packet_state p_read, p_send;
173
174 /* Volume-based rekeying */
175 u_int64_t max_blocks_in, max_blocks_out, rekey_limit;
176
177 /* Time-based rekeying */
178 u_int32_t rekey_interval; /* how often in seconds */
179 time_t rekey_time; /* time of last rekeying */
180
181 /* roundup current message to extra_pad bytes */
182 u_char extra_pad;
183
184 /* XXX discard incoming data after MAC error */
185 u_int packet_discard;
186 size_t packet_discard_mac_already;
187 struct sshmac *packet_discard_mac;
188
189 /* Used in packet_read_poll2() */
190 u_int packlen;
191
192 /* Used in packet_send2 */
193 int rekeying;
194
195 /* Used in ssh_packet_send_mux() */
196 int mux;
197
198 /* Used in packet_set_interactive */
199 int set_interactive_called;
200
201 /* Used in packet_set_maxsize */
202 int set_maxsize_called;
203
204 /* One-off warning about weak ciphers */
205 int cipher_warning_done;
206
207 /* Hook for fuzzing inbound packets */
208 ssh_packet_hook_fn *hook_in;
209 void *hook_in_ctx;
210
211 TAILQ_HEAD(, packet) outgoing;
212 };
213
214 struct ssh *
ssh_alloc_session_state(void)215 ssh_alloc_session_state(void)
216 {
217 struct ssh *ssh = NULL;
218 struct session_state *state = NULL;
219
220 if ((ssh = calloc(1, sizeof(*ssh))) == NULL ||
221 (state = calloc(1, sizeof(*state))) == NULL ||
222 (ssh->kex = kex_new()) == NULL ||
223 (state->input = sshbuf_new()) == NULL ||
224 (state->output = sshbuf_new()) == NULL ||
225 (state->outgoing_packet = sshbuf_new()) == NULL ||
226 (state->incoming_packet = sshbuf_new()) == NULL)
227 goto fail;
228 TAILQ_INIT(&state->outgoing);
229 TAILQ_INIT(&ssh->private_keys);
230 TAILQ_INIT(&ssh->public_keys);
231 state->connection_in = -1;
232 state->connection_out = -1;
233 state->max_packet_size = 32768;
234 state->packet_timeout_ms = -1;
235 state->p_send.packets = state->p_read.packets = 0;
236 state->initialized = 1;
237 /*
238 * ssh_packet_send2() needs to queue packets until
239 * we've done the initial key exchange.
240 */
241 state->rekeying = 1;
242 ssh->state = state;
243 return ssh;
244 fail:
245 if (ssh) {
246 kex_free(ssh->kex);
247 free(ssh);
248 }
249 if (state) {
250 sshbuf_free(state->input);
251 sshbuf_free(state->output);
252 sshbuf_free(state->incoming_packet);
253 sshbuf_free(state->outgoing_packet);
254 free(state);
255 }
256 return NULL;
257 }
258
259 void
ssh_packet_set_input_hook(struct ssh * ssh,ssh_packet_hook_fn * hook,void * ctx)260 ssh_packet_set_input_hook(struct ssh *ssh, ssh_packet_hook_fn *hook, void *ctx)
261 {
262 ssh->state->hook_in = hook;
263 ssh->state->hook_in_ctx = ctx;
264 }
265
266 /* Returns nonzero if rekeying is in progress */
267 int
ssh_packet_is_rekeying(struct ssh * ssh)268 ssh_packet_is_rekeying(struct ssh *ssh)
269 {
270 return ssh->state->rekeying ||
271 (ssh->kex != NULL && ssh->kex->done == 0);
272 }
273
274 /*
275 * Sets the descriptors used for communication.
276 */
277 struct ssh *
ssh_packet_set_connection(struct ssh * ssh,int fd_in,int fd_out)278 ssh_packet_set_connection(struct ssh *ssh, int fd_in, int fd_out)
279 {
280 struct session_state *state;
281 const struct sshcipher *none = cipher_by_name("none");
282 int r;
283
284 if (none == NULL) {
285 error_f("cannot load cipher 'none'");
286 return NULL;
287 }
288 if (ssh == NULL)
289 ssh = ssh_alloc_session_state();
290 if (ssh == NULL) {
291 error_f("could not allocate state");
292 return NULL;
293 }
294 state = ssh->state;
295 state->connection_in = fd_in;
296 state->connection_out = fd_out;
297 if ((r = cipher_init(&state->send_context, none,
298 (const u_char *)"", 0, NULL, 0, CIPHER_ENCRYPT)) != 0 ||
299 (r = cipher_init(&state->receive_context, none,
300 (const u_char *)"", 0, NULL, 0, CIPHER_DECRYPT)) != 0) {
301 error_fr(r, "cipher_init failed");
302 free(ssh); /* XXX need ssh_free_session_state? */
303 return NULL;
304 }
305 state->newkeys[MODE_IN] = state->newkeys[MODE_OUT] = NULL;
306 /*
307 * Cache the IP address of the remote connection for use in error
308 * messages that might be generated after the connection has closed.
309 */
310 (void)ssh_remote_ipaddr(ssh);
311 return ssh;
312 }
313
314 void
ssh_packet_set_timeout(struct ssh * ssh,int timeout,int count)315 ssh_packet_set_timeout(struct ssh *ssh, int timeout, int count)
316 {
317 struct session_state *state = ssh->state;
318
319 if (timeout <= 0 || count <= 0) {
320 state->packet_timeout_ms = -1;
321 return;
322 }
323 if ((INT_MAX / 1000) / count < timeout)
324 state->packet_timeout_ms = INT_MAX;
325 else
326 state->packet_timeout_ms = timeout * count * 1000;
327 }
328
329 void
ssh_packet_set_mux(struct ssh * ssh)330 ssh_packet_set_mux(struct ssh *ssh)
331 {
332 ssh->state->mux = 1;
333 ssh->state->rekeying = 0;
334 kex_free(ssh->kex);
335 ssh->kex = NULL;
336 }
337
338 int
ssh_packet_get_mux(struct ssh * ssh)339 ssh_packet_get_mux(struct ssh *ssh)
340 {
341 return ssh->state->mux;
342 }
343
344 int
ssh_packet_set_log_preamble(struct ssh * ssh,const char * fmt,...)345 ssh_packet_set_log_preamble(struct ssh *ssh, const char *fmt, ...)
346 {
347 va_list args;
348 int r;
349
350 free(ssh->log_preamble);
351 if (fmt == NULL)
352 ssh->log_preamble = NULL;
353 else {
354 va_start(args, fmt);
355 r = vasprintf(&ssh->log_preamble, fmt, args);
356 va_end(args);
357 if (r < 0 || ssh->log_preamble == NULL)
358 return SSH_ERR_ALLOC_FAIL;
359 }
360 return 0;
361 }
362
363 int
ssh_packet_stop_discard(struct ssh * ssh)364 ssh_packet_stop_discard(struct ssh *ssh)
365 {
366 struct session_state *state = ssh->state;
367 int r;
368
369 if (state->packet_discard_mac) {
370 char buf[1024];
371 size_t dlen = PACKET_MAX_SIZE;
372
373 if (dlen > state->packet_discard_mac_already)
374 dlen -= state->packet_discard_mac_already;
375 memset(buf, 'a', sizeof(buf));
376 while (sshbuf_len(state->incoming_packet) < dlen)
377 if ((r = sshbuf_put(state->incoming_packet, buf,
378 sizeof(buf))) != 0)
379 return r;
380 (void) mac_compute(state->packet_discard_mac,
381 state->p_read.seqnr,
382 sshbuf_ptr(state->incoming_packet), dlen,
383 NULL, 0);
384 }
385 logit("Finished discarding for %.200s port %d",
386 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
387 return SSH_ERR_MAC_INVALID;
388 }
389
390 static int
ssh_packet_start_discard(struct ssh * ssh,struct sshenc * enc,struct sshmac * mac,size_t mac_already,u_int discard)391 ssh_packet_start_discard(struct ssh *ssh, struct sshenc *enc,
392 struct sshmac *mac, size_t mac_already, u_int discard)
393 {
394 struct session_state *state = ssh->state;
395 int r;
396
397 if (enc == NULL || !cipher_is_cbc(enc->cipher) || (mac && mac->etm)) {
398 if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0)
399 return r;
400 return SSH_ERR_MAC_INVALID;
401 }
402 /*
403 * Record number of bytes over which the mac has already
404 * been computed in order to minimize timing attacks.
405 */
406 if (mac && mac->enabled) {
407 state->packet_discard_mac = mac;
408 state->packet_discard_mac_already = mac_already;
409 }
410 if (sshbuf_len(state->input) >= discard)
411 return ssh_packet_stop_discard(ssh);
412 state->packet_discard = discard - sshbuf_len(state->input);
413 return 0;
414 }
415
416 /* Returns 1 if remote host is connected via socket, 0 if not. */
417
418 int
ssh_packet_connection_is_on_socket(struct ssh * ssh)419 ssh_packet_connection_is_on_socket(struct ssh *ssh)
420 {
421 struct session_state *state;
422 struct sockaddr_storage from, to;
423 socklen_t fromlen, tolen;
424
425 if (ssh == NULL || ssh->state == NULL)
426 return 0;
427
428 state = ssh->state;
429 if (state->connection_in == -1 || state->connection_out == -1)
430 return 0;
431 /* filedescriptors in and out are the same, so it's a socket */
432 if (state->connection_in == state->connection_out)
433 return 1;
434 fromlen = sizeof(from);
435 memset(&from, 0, sizeof(from));
436 if (getpeername(state->connection_in, (struct sockaddr *)&from,
437 &fromlen) == -1)
438 return 0;
439 tolen = sizeof(to);
440 memset(&to, 0, sizeof(to));
441 if (getpeername(state->connection_out, (struct sockaddr *)&to,
442 &tolen) == -1)
443 return 0;
444 if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0)
445 return 0;
446 if (from.ss_family != AF_INET && from.ss_family != AF_INET6)
447 return 0;
448 return 1;
449 }
450
451 void
ssh_packet_get_bytes(struct ssh * ssh,u_int64_t * ibytes,u_int64_t * obytes)452 ssh_packet_get_bytes(struct ssh *ssh, u_int64_t *ibytes, u_int64_t *obytes)
453 {
454 if (ibytes)
455 *ibytes = ssh->state->p_read.bytes;
456 if (obytes)
457 *obytes = ssh->state->p_send.bytes;
458 }
459
460 int
ssh_packet_connection_af(struct ssh * ssh)461 ssh_packet_connection_af(struct ssh *ssh)
462 {
463 return get_sock_af(ssh->state->connection_out);
464 }
465
466 /* Sets the connection into non-blocking mode. */
467
468 void
ssh_packet_set_nonblocking(struct ssh * ssh)469 ssh_packet_set_nonblocking(struct ssh *ssh)
470 {
471 /* Set the socket into non-blocking mode. */
472 set_nonblock(ssh->state->connection_in);
473
474 if (ssh->state->connection_out != ssh->state->connection_in)
475 set_nonblock(ssh->state->connection_out);
476 }
477
478 /* Returns the socket used for reading. */
479
480 int
ssh_packet_get_connection_in(struct ssh * ssh)481 ssh_packet_get_connection_in(struct ssh *ssh)
482 {
483 return ssh->state->connection_in;
484 }
485
486 /* Returns the descriptor used for writing. */
487
488 int
ssh_packet_get_connection_out(struct ssh * ssh)489 ssh_packet_get_connection_out(struct ssh *ssh)
490 {
491 return ssh->state->connection_out;
492 }
493
494 /*
495 * Returns the IP-address of the remote host as a string. The returned
496 * string must not be freed.
497 */
498
499 const char *
ssh_remote_ipaddr(struct ssh * ssh)500 ssh_remote_ipaddr(struct ssh *ssh)
501 {
502 int sock;
503
504 /* Check whether we have cached the ipaddr. */
505 if (ssh->remote_ipaddr == NULL) {
506 if (ssh_packet_connection_is_on_socket(ssh)) {
507 sock = ssh->state->connection_in;
508 ssh->remote_ipaddr = get_peer_ipaddr(sock);
509 ssh->remote_port = get_peer_port(sock);
510 ssh->local_ipaddr = get_local_ipaddr(sock);
511 ssh->local_port = get_local_port(sock);
512 } else {
513 ssh->remote_ipaddr = xstrdup("UNKNOWN");
514 ssh->remote_port = 65535;
515 ssh->local_ipaddr = xstrdup("UNKNOWN");
516 ssh->local_port = 65535;
517 }
518 }
519 return ssh->remote_ipaddr;
520 }
521
522 /* Returns the port number of the remote host. */
523
524 int
ssh_remote_port(struct ssh * ssh)525 ssh_remote_port(struct ssh *ssh)
526 {
527 (void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */
528 return ssh->remote_port;
529 }
530
531 /*
532 * Returns the IP-address of the local host as a string. The returned
533 * string must not be freed.
534 */
535
536 const char *
ssh_local_ipaddr(struct ssh * ssh)537 ssh_local_ipaddr(struct ssh *ssh)
538 {
539 (void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */
540 return ssh->local_ipaddr;
541 }
542
543 /* Returns the port number of the local host. */
544
545 int
ssh_local_port(struct ssh * ssh)546 ssh_local_port(struct ssh *ssh)
547 {
548 (void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */
549 return ssh->local_port;
550 }
551
552 /* Returns the routing domain of the input socket, or NULL if unavailable */
553 const char *
ssh_packet_rdomain_in(struct ssh * ssh)554 ssh_packet_rdomain_in(struct ssh *ssh)
555 {
556 if (ssh->rdomain_in != NULL)
557 return ssh->rdomain_in;
558 if (!ssh_packet_connection_is_on_socket(ssh))
559 return NULL;
560 ssh->rdomain_in = get_rdomain(ssh->state->connection_in);
561 return ssh->rdomain_in;
562 }
563
564 /* Closes the connection and clears and frees internal data structures. */
565
566 static void
ssh_packet_close_internal(struct ssh * ssh,int do_close)567 ssh_packet_close_internal(struct ssh *ssh, int do_close)
568 {
569 struct session_state *state = ssh->state;
570 u_int mode;
571
572 if (!state->initialized)
573 return;
574 state->initialized = 0;
575 if (do_close) {
576 if (state->connection_in == state->connection_out) {
577 close(state->connection_out);
578 } else {
579 close(state->connection_in);
580 close(state->connection_out);
581 }
582 }
583 sshbuf_free(state->input);
584 sshbuf_free(state->output);
585 sshbuf_free(state->outgoing_packet);
586 sshbuf_free(state->incoming_packet);
587 for (mode = 0; mode < MODE_MAX; mode++) {
588 kex_free_newkeys(state->newkeys[mode]); /* current keys */
589 state->newkeys[mode] = NULL;
590 ssh_clear_newkeys(ssh, mode); /* next keys */
591 }
592 #ifdef WITH_ZLIB
593 /* compression state is in shared mem, so we can only release it once */
594 if (do_close && state->compression_buffer) {
595 sshbuf_free(state->compression_buffer);
596 if (state->compression_out_started) {
597 z_streamp stream = &state->compression_out_stream;
598 debug("compress outgoing: "
599 "raw data %llu, compressed %llu, factor %.2f",
600 (unsigned long long)stream->total_in,
601 (unsigned long long)stream->total_out,
602 stream->total_in == 0 ? 0.0 :
603 (double) stream->total_out / stream->total_in);
604 if (state->compression_out_failures == 0)
605 deflateEnd(stream);
606 }
607 if (state->compression_in_started) {
608 z_streamp stream = &state->compression_in_stream;
609 debug("compress incoming: "
610 "raw data %llu, compressed %llu, factor %.2f",
611 (unsigned long long)stream->total_out,
612 (unsigned long long)stream->total_in,
613 stream->total_out == 0 ? 0.0 :
614 (double) stream->total_in / stream->total_out);
615 if (state->compression_in_failures == 0)
616 inflateEnd(stream);
617 }
618 }
619 #endif /* WITH_ZLIB */
620 cipher_free(state->send_context);
621 cipher_free(state->receive_context);
622 state->send_context = state->receive_context = NULL;
623 if (do_close) {
624 free(ssh->local_ipaddr);
625 ssh->local_ipaddr = NULL;
626 free(ssh->remote_ipaddr);
627 ssh->remote_ipaddr = NULL;
628 free(ssh->state);
629 ssh->state = NULL;
630 kex_free(ssh->kex);
631 ssh->kex = NULL;
632 }
633 }
634
635 void
ssh_packet_close(struct ssh * ssh)636 ssh_packet_close(struct ssh *ssh)
637 {
638 ssh_packet_close_internal(ssh, 1);
639 }
640
641 void
ssh_packet_clear_keys(struct ssh * ssh)642 ssh_packet_clear_keys(struct ssh *ssh)
643 {
644 ssh_packet_close_internal(ssh, 0);
645 }
646
647 /* Sets remote side protocol flags. */
648
649 void
ssh_packet_set_protocol_flags(struct ssh * ssh,u_int protocol_flags)650 ssh_packet_set_protocol_flags(struct ssh *ssh, u_int protocol_flags)
651 {
652 ssh->state->remote_protocol_flags = protocol_flags;
653 }
654
655 /* Returns the remote protocol flags set earlier by the above function. */
656
657 u_int
ssh_packet_get_protocol_flags(struct ssh * ssh)658 ssh_packet_get_protocol_flags(struct ssh *ssh)
659 {
660 return ssh->state->remote_protocol_flags;
661 }
662
663 /*
664 * Starts packet compression from the next packet on in both directions.
665 * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip.
666 */
667
668 static int
ssh_packet_init_compression(struct ssh * ssh)669 ssh_packet_init_compression(struct ssh *ssh)
670 {
671 if (!ssh->state->compression_buffer &&
672 ((ssh->state->compression_buffer = sshbuf_new()) == NULL))
673 return SSH_ERR_ALLOC_FAIL;
674 return 0;
675 }
676
677 #ifdef WITH_ZLIB
678 static int
start_compression_out(struct ssh * ssh,int level)679 start_compression_out(struct ssh *ssh, int level)
680 {
681 if (level < 1 || level > 9)
682 return SSH_ERR_INVALID_ARGUMENT;
683 debug("Enabling compression at level %d.", level);
684 if (ssh->state->compression_out_started == 1)
685 deflateEnd(&ssh->state->compression_out_stream);
686 switch (deflateInit(&ssh->state->compression_out_stream, level)) {
687 case Z_OK:
688 ssh->state->compression_out_started = 1;
689 break;
690 case Z_MEM_ERROR:
691 return SSH_ERR_ALLOC_FAIL;
692 default:
693 return SSH_ERR_INTERNAL_ERROR;
694 }
695 return 0;
696 }
697
698 static int
start_compression_in(struct ssh * ssh)699 start_compression_in(struct ssh *ssh)
700 {
701 if (ssh->state->compression_in_started == 1)
702 inflateEnd(&ssh->state->compression_in_stream);
703 switch (inflateInit(&ssh->state->compression_in_stream)) {
704 case Z_OK:
705 ssh->state->compression_in_started = 1;
706 break;
707 case Z_MEM_ERROR:
708 return SSH_ERR_ALLOC_FAIL;
709 default:
710 return SSH_ERR_INTERNAL_ERROR;
711 }
712 return 0;
713 }
714
715 /* XXX remove need for separate compression buffer */
716 static int
compress_buffer(struct ssh * ssh,struct sshbuf * in,struct sshbuf * out)717 compress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out)
718 {
719 u_char buf[4096];
720 int r, status;
721
722 if (ssh->state->compression_out_started != 1)
723 return SSH_ERR_INTERNAL_ERROR;
724
725 /* This case is not handled below. */
726 if (sshbuf_len(in) == 0)
727 return 0;
728
729 /* Input is the contents of the input buffer. */
730 if ((ssh->state->compression_out_stream.next_in =
731 sshbuf_mutable_ptr(in)) == NULL)
732 return SSH_ERR_INTERNAL_ERROR;
733 ssh->state->compression_out_stream.avail_in = sshbuf_len(in);
734
735 /* Loop compressing until deflate() returns with avail_out != 0. */
736 do {
737 /* Set up fixed-size output buffer. */
738 ssh->state->compression_out_stream.next_out = buf;
739 ssh->state->compression_out_stream.avail_out = sizeof(buf);
740
741 /* Compress as much data into the buffer as possible. */
742 status = deflate(&ssh->state->compression_out_stream,
743 Z_PARTIAL_FLUSH);
744 switch (status) {
745 case Z_MEM_ERROR:
746 return SSH_ERR_ALLOC_FAIL;
747 case Z_OK:
748 /* Append compressed data to output_buffer. */
749 if ((r = sshbuf_put(out, buf, sizeof(buf) -
750 ssh->state->compression_out_stream.avail_out)) != 0)
751 return r;
752 break;
753 case Z_STREAM_ERROR:
754 default:
755 ssh->state->compression_out_failures++;
756 return SSH_ERR_INVALID_FORMAT;
757 }
758 } while (ssh->state->compression_out_stream.avail_out == 0);
759 return 0;
760 }
761
762 static int
uncompress_buffer(struct ssh * ssh,struct sshbuf * in,struct sshbuf * out)763 uncompress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out)
764 {
765 u_char buf[4096];
766 int r, status;
767
768 if (ssh->state->compression_in_started != 1)
769 return SSH_ERR_INTERNAL_ERROR;
770
771 if ((ssh->state->compression_in_stream.next_in =
772 sshbuf_mutable_ptr(in)) == NULL)
773 return SSH_ERR_INTERNAL_ERROR;
774 ssh->state->compression_in_stream.avail_in = sshbuf_len(in);
775
776 for (;;) {
777 /* Set up fixed-size output buffer. */
778 ssh->state->compression_in_stream.next_out = buf;
779 ssh->state->compression_in_stream.avail_out = sizeof(buf);
780
781 status = inflate(&ssh->state->compression_in_stream,
782 Z_SYNC_FLUSH);
783 switch (status) {
784 case Z_OK:
785 if ((r = sshbuf_put(out, buf, sizeof(buf) -
786 ssh->state->compression_in_stream.avail_out)) != 0)
787 return r;
788 break;
789 case Z_BUF_ERROR:
790 /*
791 * Comments in zlib.h say that we should keep calling
792 * inflate() until we get an error. This appears to
793 * be the error that we get.
794 */
795 return 0;
796 case Z_DATA_ERROR:
797 return SSH_ERR_INVALID_FORMAT;
798 case Z_MEM_ERROR:
799 return SSH_ERR_ALLOC_FAIL;
800 case Z_STREAM_ERROR:
801 default:
802 ssh->state->compression_in_failures++;
803 return SSH_ERR_INTERNAL_ERROR;
804 }
805 }
806 /* NOTREACHED */
807 }
808
809 #else /* WITH_ZLIB */
810
811 static int
start_compression_out(struct ssh * ssh,int level)812 start_compression_out(struct ssh *ssh, int level)
813 {
814 return SSH_ERR_INTERNAL_ERROR;
815 }
816
817 static int
start_compression_in(struct ssh * ssh)818 start_compression_in(struct ssh *ssh)
819 {
820 return SSH_ERR_INTERNAL_ERROR;
821 }
822
823 static int
compress_buffer(struct ssh * ssh,struct sshbuf * in,struct sshbuf * out)824 compress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out)
825 {
826 return SSH_ERR_INTERNAL_ERROR;
827 }
828
829 static int
uncompress_buffer(struct ssh * ssh,struct sshbuf * in,struct sshbuf * out)830 uncompress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out)
831 {
832 return SSH_ERR_INTERNAL_ERROR;
833 }
834 #endif /* WITH_ZLIB */
835
836 void
ssh_clear_newkeys(struct ssh * ssh,int mode)837 ssh_clear_newkeys(struct ssh *ssh, int mode)
838 {
839 if (ssh->kex && ssh->kex->newkeys[mode]) {
840 kex_free_newkeys(ssh->kex->newkeys[mode]);
841 ssh->kex->newkeys[mode] = NULL;
842 }
843 }
844
845 int
ssh_set_newkeys(struct ssh * ssh,int mode)846 ssh_set_newkeys(struct ssh *ssh, int mode)
847 {
848 struct session_state *state = ssh->state;
849 struct sshenc *enc;
850 struct sshmac *mac;
851 struct sshcomp *comp;
852 struct sshcipher_ctx **ccp;
853 struct packet_state *ps;
854 u_int64_t *max_blocks;
855 const char *wmsg;
856 int r, crypt_type;
857 const char *dir = mode == MODE_OUT ? "out" : "in";
858
859 debug2_f("mode %d", mode);
860
861 if (mode == MODE_OUT) {
862 ccp = &state->send_context;
863 crypt_type = CIPHER_ENCRYPT;
864 ps = &state->p_send;
865 max_blocks = &state->max_blocks_out;
866 } else {
867 ccp = &state->receive_context;
868 crypt_type = CIPHER_DECRYPT;
869 ps = &state->p_read;
870 max_blocks = &state->max_blocks_in;
871 }
872 if (state->newkeys[mode] != NULL) {
873 debug_f("rekeying %s, input %llu bytes %llu blocks, "
874 "output %llu bytes %llu blocks", dir,
875 (unsigned long long)state->p_read.bytes,
876 (unsigned long long)state->p_read.blocks,
877 (unsigned long long)state->p_send.bytes,
878 (unsigned long long)state->p_send.blocks);
879 kex_free_newkeys(state->newkeys[mode]);
880 state->newkeys[mode] = NULL;
881 }
882 /* note that both bytes and the seqnr are not reset */
883 ps->packets = ps->blocks = 0;
884 /* move newkeys from kex to state */
885 if ((state->newkeys[mode] = ssh->kex->newkeys[mode]) == NULL)
886 return SSH_ERR_INTERNAL_ERROR;
887 ssh->kex->newkeys[mode] = NULL;
888 enc = &state->newkeys[mode]->enc;
889 mac = &state->newkeys[mode]->mac;
890 comp = &state->newkeys[mode]->comp;
891 if (cipher_authlen(enc->cipher) == 0) {
892 if ((r = mac_init(mac)) != 0)
893 return r;
894 }
895 mac->enabled = 1;
896 DBG(debug_f("cipher_init: %s", dir));
897 cipher_free(*ccp);
898 *ccp = NULL;
899 if ((r = cipher_init(ccp, enc->cipher, enc->key, enc->key_len,
900 enc->iv, enc->iv_len, crypt_type)) != 0)
901 return r;
902 if (!state->cipher_warning_done &&
903 (wmsg = cipher_warning_message(*ccp)) != NULL) {
904 error("Warning: %s", wmsg);
905 state->cipher_warning_done = 1;
906 }
907 /* Deleting the keys does not gain extra security */
908 /* explicit_bzero(enc->iv, enc->block_size);
909 explicit_bzero(enc->key, enc->key_len);
910 explicit_bzero(mac->key, mac->key_len); */
911 if ((comp->type == COMP_ZLIB ||
912 (comp->type == COMP_DELAYED &&
913 state->after_authentication)) && comp->enabled == 0) {
914 if ((r = ssh_packet_init_compression(ssh)) < 0)
915 return r;
916 if (mode == MODE_OUT) {
917 if ((r = start_compression_out(ssh, 6)) != 0)
918 return r;
919 } else {
920 if ((r = start_compression_in(ssh)) != 0)
921 return r;
922 }
923 comp->enabled = 1;
924 }
925 /*
926 * The 2^(blocksize*2) limit is too expensive for 3DES,
927 * so enforce a 1GB limit for small blocksizes.
928 * See RFC4344 section 3.2.
929 */
930 if (enc->block_size >= 16)
931 *max_blocks = (u_int64_t)1 << (enc->block_size*2);
932 else
933 *max_blocks = ((u_int64_t)1 << 30) / enc->block_size;
934 if (state->rekey_limit)
935 *max_blocks = MINIMUM(*max_blocks,
936 state->rekey_limit / enc->block_size);
937 debug("rekey %s after %llu blocks", dir,
938 (unsigned long long)*max_blocks);
939 return 0;
940 }
941
942 #define MAX_PACKETS (1U<<31)
943 static int
ssh_packet_need_rekeying(struct ssh * ssh,u_int outbound_packet_len)944 ssh_packet_need_rekeying(struct ssh *ssh, u_int outbound_packet_len)
945 {
946 struct session_state *state = ssh->state;
947 u_int32_t out_blocks;
948
949 /* XXX client can't cope with rekeying pre-auth */
950 if (!state->after_authentication)
951 return 0;
952
953 /* Haven't keyed yet or KEX in progress. */
954 if (ssh_packet_is_rekeying(ssh))
955 return 0;
956
957 /* Peer can't rekey */
958 if (ssh->compat & SSH_BUG_NOREKEY)
959 return 0;
960
961 /*
962 * Permit one packet in or out per rekey - this allows us to
963 * make progress when rekey limits are very small.
964 */
965 if (state->p_send.packets == 0 && state->p_read.packets == 0)
966 return 0;
967
968 /* Time-based rekeying */
969 if (state->rekey_interval != 0 &&
970 (int64_t)state->rekey_time + state->rekey_interval <= monotime())
971 return 1;
972
973 /*
974 * Always rekey when MAX_PACKETS sent in either direction
975 * As per RFC4344 section 3.1 we do this after 2^31 packets.
976 */
977 if (state->p_send.packets > MAX_PACKETS ||
978 state->p_read.packets > MAX_PACKETS)
979 return 1;
980
981 /* Rekey after (cipher-specific) maximum blocks */
982 out_blocks = ROUNDUP(outbound_packet_len,
983 state->newkeys[MODE_OUT]->enc.block_size);
984 return (state->max_blocks_out &&
985 (state->p_send.blocks + out_blocks > state->max_blocks_out)) ||
986 (state->max_blocks_in &&
987 (state->p_read.blocks > state->max_blocks_in));
988 }
989
990 int
ssh_packet_check_rekey(struct ssh * ssh)991 ssh_packet_check_rekey(struct ssh *ssh)
992 {
993 if (!ssh_packet_need_rekeying(ssh, 0))
994 return 0;
995 debug3_f("rekex triggered");
996 return kex_start_rekex(ssh);
997 }
998
999 /*
1000 * Delayed compression for SSH2 is enabled after authentication:
1001 * This happens on the server side after a SSH2_MSG_USERAUTH_SUCCESS is sent,
1002 * and on the client side after a SSH2_MSG_USERAUTH_SUCCESS is received.
1003 */
1004 static int
ssh_packet_enable_delayed_compress(struct ssh * ssh)1005 ssh_packet_enable_delayed_compress(struct ssh *ssh)
1006 {
1007 struct session_state *state = ssh->state;
1008 struct sshcomp *comp = NULL;
1009 int r, mode;
1010
1011 /*
1012 * Remember that we are past the authentication step, so rekeying
1013 * with COMP_DELAYED will turn on compression immediately.
1014 */
1015 state->after_authentication = 1;
1016 for (mode = 0; mode < MODE_MAX; mode++) {
1017 /* protocol error: USERAUTH_SUCCESS received before NEWKEYS */
1018 if (state->newkeys[mode] == NULL)
1019 continue;
1020 comp = &state->newkeys[mode]->comp;
1021 if (comp && !comp->enabled && comp->type == COMP_DELAYED) {
1022 if ((r = ssh_packet_init_compression(ssh)) != 0)
1023 return r;
1024 if (mode == MODE_OUT) {
1025 if ((r = start_compression_out(ssh, 6)) != 0)
1026 return r;
1027 } else {
1028 if ((r = start_compression_in(ssh)) != 0)
1029 return r;
1030 }
1031 comp->enabled = 1;
1032 }
1033 }
1034 return 0;
1035 }
1036
1037 /* Used to mute debug logging for noisy packet types */
1038 int
ssh_packet_log_type(u_char type)1039 ssh_packet_log_type(u_char type)
1040 {
1041 switch (type) {
1042 case SSH2_MSG_CHANNEL_DATA:
1043 case SSH2_MSG_CHANNEL_EXTENDED_DATA:
1044 case SSH2_MSG_CHANNEL_WINDOW_ADJUST:
1045 return 0;
1046 default:
1047 return 1;
1048 }
1049 }
1050
1051 /*
1052 * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue)
1053 */
1054 int
ssh_packet_send2_wrapped(struct ssh * ssh)1055 ssh_packet_send2_wrapped(struct ssh *ssh)
1056 {
1057 struct session_state *state = ssh->state;
1058 u_char type, *cp, macbuf[SSH_DIGEST_MAX_LENGTH];
1059 u_char tmp, padlen, pad = 0;
1060 u_int authlen = 0, aadlen = 0;
1061 u_int len;
1062 struct sshenc *enc = NULL;
1063 struct sshmac *mac = NULL;
1064 struct sshcomp *comp = NULL;
1065 int r, block_size;
1066
1067 if (state->newkeys[MODE_OUT] != NULL) {
1068 enc = &state->newkeys[MODE_OUT]->enc;
1069 mac = &state->newkeys[MODE_OUT]->mac;
1070 comp = &state->newkeys[MODE_OUT]->comp;
1071 /* disable mac for authenticated encryption */
1072 if ((authlen = cipher_authlen(enc->cipher)) != 0)
1073 mac = NULL;
1074 }
1075 block_size = enc ? enc->block_size : 8;
1076 aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0;
1077
1078 type = (sshbuf_ptr(state->outgoing_packet))[5];
1079 if (ssh_packet_log_type(type))
1080 debug3("send packet: type %u", type);
1081 #ifdef PACKET_DEBUG
1082 fprintf(stderr, "plain: ");
1083 sshbuf_dump(state->outgoing_packet, stderr);
1084 #endif
1085
1086 if (comp && comp->enabled) {
1087 len = sshbuf_len(state->outgoing_packet);
1088 /* skip header, compress only payload */
1089 if ((r = sshbuf_consume(state->outgoing_packet, 5)) != 0)
1090 goto out;
1091 sshbuf_reset(state->compression_buffer);
1092 if ((r = compress_buffer(ssh, state->outgoing_packet,
1093 state->compression_buffer)) != 0)
1094 goto out;
1095 sshbuf_reset(state->outgoing_packet);
1096 if ((r = sshbuf_put(state->outgoing_packet,
1097 "\0\0\0\0\0", 5)) != 0 ||
1098 (r = sshbuf_putb(state->outgoing_packet,
1099 state->compression_buffer)) != 0)
1100 goto out;
1101 DBG(debug("compression: raw %d compressed %zd", len,
1102 sshbuf_len(state->outgoing_packet)));
1103 }
1104
1105 /* sizeof (packet_len + pad_len + payload) */
1106 len = sshbuf_len(state->outgoing_packet);
1107
1108 /*
1109 * calc size of padding, alloc space, get random data,
1110 * minimum padding is 4 bytes
1111 */
1112 len -= aadlen; /* packet length is not encrypted for EtM modes */
1113 padlen = block_size - (len % block_size);
1114 if (padlen < 4)
1115 padlen += block_size;
1116 if (state->extra_pad) {
1117 tmp = state->extra_pad;
1118 state->extra_pad =
1119 ROUNDUP(state->extra_pad, block_size);
1120 /* check if roundup overflowed */
1121 if (state->extra_pad < tmp)
1122 return SSH_ERR_INVALID_ARGUMENT;
1123 tmp = (len + padlen) % state->extra_pad;
1124 /* Check whether pad calculation below will underflow */
1125 if (tmp > state->extra_pad)
1126 return SSH_ERR_INVALID_ARGUMENT;
1127 pad = state->extra_pad - tmp;
1128 DBG(debug3_f("adding %d (len %d padlen %d extra_pad %d)",
1129 pad, len, padlen, state->extra_pad));
1130 tmp = padlen;
1131 padlen += pad;
1132 /* Check whether padlen calculation overflowed */
1133 if (padlen < tmp)
1134 return SSH_ERR_INVALID_ARGUMENT; /* overflow */
1135 state->extra_pad = 0;
1136 }
1137 if ((r = sshbuf_reserve(state->outgoing_packet, padlen, &cp)) != 0)
1138 goto out;
1139 if (enc && !cipher_ctx_is_plaintext(state->send_context)) {
1140 /* random padding */
1141 arc4random_buf(cp, padlen);
1142 } else {
1143 /* clear padding */
1144 explicit_bzero(cp, padlen);
1145 }
1146 /* sizeof (packet_len + pad_len + payload + padding) */
1147 len = sshbuf_len(state->outgoing_packet);
1148 cp = sshbuf_mutable_ptr(state->outgoing_packet);
1149 if (cp == NULL) {
1150 r = SSH_ERR_INTERNAL_ERROR;
1151 goto out;
1152 }
1153 /* packet_length includes payload, padding and padding length field */
1154 POKE_U32(cp, len - 4);
1155 cp[4] = padlen;
1156 DBG(debug("send: len %d (includes padlen %d, aadlen %d)",
1157 len, padlen, aadlen));
1158
1159 /* compute MAC over seqnr and packet(length fields, payload, padding) */
1160 if (mac && mac->enabled && !mac->etm) {
1161 if ((r = mac_compute(mac, state->p_send.seqnr,
1162 sshbuf_ptr(state->outgoing_packet), len,
1163 macbuf, sizeof(macbuf))) != 0)
1164 goto out;
1165 DBG(debug("done calc MAC out #%d", state->p_send.seqnr));
1166 }
1167 /* encrypt packet and append to output buffer. */
1168 if ((r = sshbuf_reserve(state->output,
1169 sshbuf_len(state->outgoing_packet) + authlen, &cp)) != 0)
1170 goto out;
1171 if ((r = cipher_crypt(state->send_context, state->p_send.seqnr, cp,
1172 sshbuf_ptr(state->outgoing_packet),
1173 len - aadlen, aadlen, authlen)) != 0)
1174 goto out;
1175 /* append unencrypted MAC */
1176 if (mac && mac->enabled) {
1177 if (mac->etm) {
1178 /* EtM: compute mac over aadlen + cipher text */
1179 if ((r = mac_compute(mac, state->p_send.seqnr,
1180 cp, len, macbuf, sizeof(macbuf))) != 0)
1181 goto out;
1182 DBG(debug("done calc MAC(EtM) out #%d",
1183 state->p_send.seqnr));
1184 }
1185 if ((r = sshbuf_put(state->output, macbuf, mac->mac_len)) != 0)
1186 goto out;
1187 }
1188 #ifdef PACKET_DEBUG
1189 fprintf(stderr, "encrypted: ");
1190 sshbuf_dump(state->output, stderr);
1191 #endif
1192 /* increment sequence number for outgoing packets */
1193 if (++state->p_send.seqnr == 0)
1194 logit("outgoing seqnr wraps around");
1195 if (++state->p_send.packets == 0)
1196 if (!(ssh->compat & SSH_BUG_NOREKEY))
1197 return SSH_ERR_NEED_REKEY;
1198 state->p_send.blocks += len / block_size;
1199 state->p_send.bytes += len;
1200 sshbuf_reset(state->outgoing_packet);
1201
1202 if (type == SSH2_MSG_NEWKEYS)
1203 r = ssh_set_newkeys(ssh, MODE_OUT);
1204 else if (type == SSH2_MSG_USERAUTH_SUCCESS && state->server_side)
1205 r = ssh_packet_enable_delayed_compress(ssh);
1206 else
1207 r = 0;
1208 out:
1209 if (r < 0)
1210 return r;
1211 else
1212 return len - 4;
1213 }
1214
1215 /* returns non-zero if the specified packet type is usec by KEX */
1216 static int
ssh_packet_type_is_kex(u_char type)1217 ssh_packet_type_is_kex(u_char type)
1218 {
1219 return
1220 type >= SSH2_MSG_TRANSPORT_MIN &&
1221 type <= SSH2_MSG_TRANSPORT_MAX &&
1222 type != SSH2_MSG_SERVICE_REQUEST &&
1223 type != SSH2_MSG_SERVICE_ACCEPT &&
1224 type != SSH2_MSG_EXT_INFO;
1225 }
1226
1227 int
ssh_packet_send2(struct ssh * ssh)1228 ssh_packet_send2(struct ssh *ssh)
1229 {
1230 struct session_state *state = ssh->state;
1231 struct packet *p;
1232 u_char type;
1233 int r, need_rekey;
1234 int packet_length;
1235
1236 if (sshbuf_len(state->outgoing_packet) < 6)
1237 return SSH_ERR_INTERNAL_ERROR;
1238 type = sshbuf_ptr(state->outgoing_packet)[5];
1239 need_rekey = !ssh_packet_type_is_kex(type) &&
1240 ssh_packet_need_rekeying(ssh, sshbuf_len(state->outgoing_packet));
1241
1242 /*
1243 * During rekeying we can only send key exchange messages.
1244 * Queue everything else.
1245 */
1246 if ((need_rekey || state->rekeying) && !ssh_packet_type_is_kex(type)) {
1247 if (need_rekey)
1248 debug3_f("rekex triggered");
1249 debug("enqueue packet: %u", type);
1250 p = calloc(1, sizeof(*p));
1251 if (p == NULL)
1252 return SSH_ERR_ALLOC_FAIL;
1253 p->type = type;
1254 p->payload = state->outgoing_packet;
1255 TAILQ_INSERT_TAIL(&state->outgoing, p, next);
1256 state->outgoing_packet = sshbuf_new();
1257 if (state->outgoing_packet == NULL)
1258 return SSH_ERR_ALLOC_FAIL;
1259 if (need_rekey) {
1260 /*
1261 * This packet triggered a rekey, so send the
1262 * KEXINIT now.
1263 * NB. reenters this function via kex_start_rekex().
1264 */
1265 return kex_start_rekex(ssh);
1266 }
1267 return 0;
1268 }
1269
1270 /* rekeying starts with sending KEXINIT */
1271 if (type == SSH2_MSG_KEXINIT)
1272 state->rekeying = 1;
1273
1274 if ((r = ssh_packet_send2_wrapped(ssh)) < 0)
1275 return r;
1276
1277 packet_length = r;
1278
1279 /* after a NEWKEYS message we can send the complete queue */
1280 if (type == SSH2_MSG_NEWKEYS) {
1281 state->rekeying = 0;
1282 state->rekey_time = monotime();
1283 while ((p = TAILQ_FIRST(&state->outgoing))) {
1284 type = p->type;
1285 /*
1286 * If this packet triggers a rekex, then skip the
1287 * remaining packets in the queue for now.
1288 * NB. re-enters this function via kex_start_rekex.
1289 */
1290 if (ssh_packet_need_rekeying(ssh,
1291 sshbuf_len(p->payload))) {
1292 debug3_f("queued packet triggered rekex");
1293 return kex_start_rekex(ssh);
1294 }
1295 debug("dequeue packet: %u", type);
1296 sshbuf_free(state->outgoing_packet);
1297 state->outgoing_packet = p->payload;
1298 TAILQ_REMOVE(&state->outgoing, p, next);
1299 memset(p, 0, sizeof(*p));
1300 free(p);
1301 if ((r = ssh_packet_send2_wrapped(ssh)) < 0)
1302 return r;
1303 packet_length += r;
1304 }
1305 }
1306 return packet_length;
1307 }
1308
1309 /*
1310 * Waits until a packet has been received, and returns its type. Note that
1311 * no other data is processed until this returns, so this function should not
1312 * be used during the interactive session.
1313 */
1314
1315 int
ssh_packet_read_seqnr(struct ssh * ssh,u_char * typep,u_int32_t * seqnr_p)1316 ssh_packet_read_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
1317 {
1318 struct session_state *state = ssh->state;
1319 int len, r, ms_remain = 0;
1320 struct pollfd pfd;
1321 char buf[8192];
1322 struct timeval start;
1323 struct timespec timespec, *timespecp = NULL;
1324
1325 DBG(debug("packet_read()"));
1326
1327 /*
1328 * Since we are blocking, ensure that all written packets have
1329 * been sent.
1330 */
1331 if ((r = ssh_packet_write_wait(ssh)) < 0)
1332 goto out;
1333
1334 /* Stay in the loop until we have received a complete packet. */
1335 for (;;) {
1336 /* Try to read a packet from the buffer. */
1337 r = ssh_packet_read_poll_seqnr(ssh, typep, seqnr_p);
1338 if (r != 0)
1339 break;
1340 /* If we got a packet, return it. */
1341 if (*typep != SSH_MSG_NONE)
1342 break;
1343 /*
1344 * Otherwise, wait for some data to arrive, add it to the
1345 * buffer, and try again.
1346 */
1347 pfd.fd = state->connection_in;
1348 pfd.events = POLLIN;
1349
1350 if (state->packet_timeout_ms > 0) {
1351 ms_remain = state->packet_timeout_ms;
1352 timespecp = ×pec;
1353 }
1354 /* Wait for some data to arrive. */
1355 for (;;) {
1356 if (state->packet_timeout_ms > 0) {
1357 ms_to_timespec(×pec, ms_remain);
1358 monotime_tv(&start);
1359 }
1360 if ((r = ppoll(&pfd, 1, timespecp, NULL)) >= 0)
1361 break;
1362 if (errno != EAGAIN && errno != EINTR) {
1363 r = SSH_ERR_SYSTEM_ERROR;
1364 goto out;
1365 }
1366 if (state->packet_timeout_ms <= 0)
1367 continue;
1368 ms_subtract_diff(&start, &ms_remain);
1369 if (ms_remain <= 0) {
1370 r = 0;
1371 break;
1372 }
1373 }
1374 if (r == 0) {
1375 r = SSH_ERR_CONN_TIMEOUT;
1376 goto out;
1377 }
1378 /* Read data from the socket. */
1379 len = read(state->connection_in, buf, sizeof(buf));
1380 if (len == 0) {
1381 r = SSH_ERR_CONN_CLOSED;
1382 goto out;
1383 }
1384 if (len == -1) {
1385 r = SSH_ERR_SYSTEM_ERROR;
1386 goto out;
1387 }
1388
1389 /* Append it to the buffer. */
1390 if ((r = ssh_packet_process_incoming(ssh, buf, len)) != 0)
1391 goto out;
1392 }
1393 out:
1394 return r;
1395 }
1396
1397 int
ssh_packet_read(struct ssh * ssh)1398 ssh_packet_read(struct ssh *ssh)
1399 {
1400 u_char type;
1401 int r;
1402
1403 if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0)
1404 fatal_fr(r, "read");
1405 return type;
1406 }
1407
1408 /*
1409 * Waits until a packet has been received, verifies that its type matches
1410 * that given, and gives a fatal error and exits if there is a mismatch.
1411 */
1412
1413 int
ssh_packet_read_expect(struct ssh * ssh,u_int expected_type)1414 ssh_packet_read_expect(struct ssh *ssh, u_int expected_type)
1415 {
1416 int r;
1417 u_char type;
1418
1419 if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0)
1420 return r;
1421 if (type != expected_type) {
1422 if ((r = sshpkt_disconnect(ssh,
1423 "Protocol error: expected packet type %d, got %d",
1424 expected_type, type)) != 0)
1425 return r;
1426 return SSH_ERR_PROTOCOL_ERROR;
1427 }
1428 return 0;
1429 }
1430
1431 static int
ssh_packet_read_poll2_mux(struct ssh * ssh,u_char * typep,u_int32_t * seqnr_p)1432 ssh_packet_read_poll2_mux(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
1433 {
1434 struct session_state *state = ssh->state;
1435 const u_char *cp;
1436 size_t need;
1437 int r;
1438
1439 if (ssh->kex)
1440 return SSH_ERR_INTERNAL_ERROR;
1441 *typep = SSH_MSG_NONE;
1442 cp = sshbuf_ptr(state->input);
1443 if (state->packlen == 0) {
1444 if (sshbuf_len(state->input) < 4 + 1)
1445 return 0; /* packet is incomplete */
1446 state->packlen = PEEK_U32(cp);
1447 if (state->packlen < 4 + 1 ||
1448 state->packlen > PACKET_MAX_SIZE)
1449 return SSH_ERR_MESSAGE_INCOMPLETE;
1450 }
1451 need = state->packlen + 4;
1452 if (sshbuf_len(state->input) < need)
1453 return 0; /* packet is incomplete */
1454 sshbuf_reset(state->incoming_packet);
1455 if ((r = sshbuf_put(state->incoming_packet, cp + 4,
1456 state->packlen)) != 0 ||
1457 (r = sshbuf_consume(state->input, need)) != 0 ||
1458 (r = sshbuf_get_u8(state->incoming_packet, NULL)) != 0 ||
1459 (r = sshbuf_get_u8(state->incoming_packet, typep)) != 0)
1460 return r;
1461 if (ssh_packet_log_type(*typep))
1462 debug3_f("type %u", *typep);
1463 /* sshbuf_dump(state->incoming_packet, stderr); */
1464 /* reset for next packet */
1465 state->packlen = 0;
1466 return r;
1467 }
1468
1469 int
ssh_packet_read_poll2(struct ssh * ssh,u_char * typep,u_int32_t * seqnr_p)1470 ssh_packet_read_poll2(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
1471 {
1472 struct session_state *state = ssh->state;
1473 u_int padlen, need;
1474 u_char *cp;
1475 u_int maclen, aadlen = 0, authlen = 0, block_size;
1476 struct sshenc *enc = NULL;
1477 struct sshmac *mac = NULL;
1478 struct sshcomp *comp = NULL;
1479 int r;
1480
1481 if (state->mux)
1482 return ssh_packet_read_poll2_mux(ssh, typep, seqnr_p);
1483
1484 *typep = SSH_MSG_NONE;
1485
1486 if (state->packet_discard)
1487 return 0;
1488
1489 if (state->newkeys[MODE_IN] != NULL) {
1490 enc = &state->newkeys[MODE_IN]->enc;
1491 mac = &state->newkeys[MODE_IN]->mac;
1492 comp = &state->newkeys[MODE_IN]->comp;
1493 /* disable mac for authenticated encryption */
1494 if ((authlen = cipher_authlen(enc->cipher)) != 0)
1495 mac = NULL;
1496 }
1497 maclen = mac && mac->enabled ? mac->mac_len : 0;
1498 block_size = enc ? enc->block_size : 8;
1499 aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0;
1500
1501 if (aadlen && state->packlen == 0) {
1502 if (cipher_get_length(state->receive_context,
1503 &state->packlen, state->p_read.seqnr,
1504 sshbuf_ptr(state->input), sshbuf_len(state->input)) != 0)
1505 return 0;
1506 if (state->packlen < 1 + 4 ||
1507 state->packlen > PACKET_MAX_SIZE) {
1508 #ifdef PACKET_DEBUG
1509 sshbuf_dump(state->input, stderr);
1510 #endif
1511 logit("Bad packet length %u.", state->packlen);
1512 if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0)
1513 return r;
1514 return SSH_ERR_CONN_CORRUPT;
1515 }
1516 sshbuf_reset(state->incoming_packet);
1517 } else if (state->packlen == 0) {
1518 /*
1519 * check if input size is less than the cipher block size,
1520 * decrypt first block and extract length of incoming packet
1521 */
1522 if (sshbuf_len(state->input) < block_size)
1523 return 0;
1524 sshbuf_reset(state->incoming_packet);
1525 if ((r = sshbuf_reserve(state->incoming_packet, block_size,
1526 &cp)) != 0)
1527 goto out;
1528 if ((r = cipher_crypt(state->receive_context,
1529 state->p_send.seqnr, cp, sshbuf_ptr(state->input),
1530 block_size, 0, 0)) != 0)
1531 goto out;
1532 state->packlen = PEEK_U32(sshbuf_ptr(state->incoming_packet));
1533 if (state->packlen < 1 + 4 ||
1534 state->packlen > PACKET_MAX_SIZE) {
1535 #ifdef PACKET_DEBUG
1536 fprintf(stderr, "input: \n");
1537 sshbuf_dump(state->input, stderr);
1538 fprintf(stderr, "incoming_packet: \n");
1539 sshbuf_dump(state->incoming_packet, stderr);
1540 #endif
1541 logit("Bad packet length %u.", state->packlen);
1542 return ssh_packet_start_discard(ssh, enc, mac, 0,
1543 PACKET_MAX_SIZE);
1544 }
1545 if ((r = sshbuf_consume(state->input, block_size)) != 0)
1546 goto out;
1547 }
1548 DBG(debug("input: packet len %u", state->packlen+4));
1549
1550 if (aadlen) {
1551 /* only the payload is encrypted */
1552 need = state->packlen;
1553 } else {
1554 /*
1555 * the payload size and the payload are encrypted, but we
1556 * have a partial packet of block_size bytes
1557 */
1558 need = 4 + state->packlen - block_size;
1559 }
1560 DBG(debug("partial packet: block %d, need %d, maclen %d, authlen %d,"
1561 " aadlen %d", block_size, need, maclen, authlen, aadlen));
1562 if (need % block_size != 0) {
1563 logit("padding error: need %d block %d mod %d",
1564 need, block_size, need % block_size);
1565 return ssh_packet_start_discard(ssh, enc, mac, 0,
1566 PACKET_MAX_SIZE - block_size);
1567 }
1568 /*
1569 * check if the entire packet has been received and
1570 * decrypt into incoming_packet:
1571 * 'aadlen' bytes are unencrypted, but authenticated.
1572 * 'need' bytes are encrypted, followed by either
1573 * 'authlen' bytes of authentication tag or
1574 * 'maclen' bytes of message authentication code.
1575 */
1576 if (sshbuf_len(state->input) < aadlen + need + authlen + maclen)
1577 return 0; /* packet is incomplete */
1578 #ifdef PACKET_DEBUG
1579 fprintf(stderr, "read_poll enc/full: ");
1580 sshbuf_dump(state->input, stderr);
1581 #endif
1582 /* EtM: check mac over encrypted input */
1583 if (mac && mac->enabled && mac->etm) {
1584 if ((r = mac_check(mac, state->p_read.seqnr,
1585 sshbuf_ptr(state->input), aadlen + need,
1586 sshbuf_ptr(state->input) + aadlen + need + authlen,
1587 maclen)) != 0) {
1588 if (r == SSH_ERR_MAC_INVALID)
1589 logit("Corrupted MAC on input.");
1590 goto out;
1591 }
1592 }
1593 if ((r = sshbuf_reserve(state->incoming_packet, aadlen + need,
1594 &cp)) != 0)
1595 goto out;
1596 if ((r = cipher_crypt(state->receive_context, state->p_read.seqnr, cp,
1597 sshbuf_ptr(state->input), need, aadlen, authlen)) != 0)
1598 goto out;
1599 if ((r = sshbuf_consume(state->input, aadlen + need + authlen)) != 0)
1600 goto out;
1601 if (mac && mac->enabled) {
1602 /* Not EtM: check MAC over cleartext */
1603 if (!mac->etm && (r = mac_check(mac, state->p_read.seqnr,
1604 sshbuf_ptr(state->incoming_packet),
1605 sshbuf_len(state->incoming_packet),
1606 sshbuf_ptr(state->input), maclen)) != 0) {
1607 if (r != SSH_ERR_MAC_INVALID)
1608 goto out;
1609 logit("Corrupted MAC on input.");
1610 if (need + block_size > PACKET_MAX_SIZE)
1611 return SSH_ERR_INTERNAL_ERROR;
1612 return ssh_packet_start_discard(ssh, enc, mac,
1613 sshbuf_len(state->incoming_packet),
1614 PACKET_MAX_SIZE - need - block_size);
1615 }
1616 /* Remove MAC from input buffer */
1617 DBG(debug("MAC #%d ok", state->p_read.seqnr));
1618 if ((r = sshbuf_consume(state->input, mac->mac_len)) != 0)
1619 goto out;
1620 }
1621 if (seqnr_p != NULL)
1622 *seqnr_p = state->p_read.seqnr;
1623 if (++state->p_read.seqnr == 0)
1624 logit("incoming seqnr wraps around");
1625 if (++state->p_read.packets == 0)
1626 if (!(ssh->compat & SSH_BUG_NOREKEY))
1627 return SSH_ERR_NEED_REKEY;
1628 state->p_read.blocks += (state->packlen + 4) / block_size;
1629 state->p_read.bytes += state->packlen + 4;
1630
1631 /* get padlen */
1632 padlen = sshbuf_ptr(state->incoming_packet)[4];
1633 DBG(debug("input: padlen %d", padlen));
1634 if (padlen < 4) {
1635 if ((r = sshpkt_disconnect(ssh,
1636 "Corrupted padlen %d on input.", padlen)) != 0 ||
1637 (r = ssh_packet_write_wait(ssh)) < 0)
1638 return r;
1639 return SSH_ERR_CONN_CORRUPT;
1640 }
1641
1642 /* skip packet size + padlen, discard padding */
1643 if ((r = sshbuf_consume(state->incoming_packet, 4 + 1)) != 0 ||
1644 ((r = sshbuf_consume_end(state->incoming_packet, padlen)) != 0))
1645 goto out;
1646
1647 DBG(debug("input: len before de-compress %zd",
1648 sshbuf_len(state->incoming_packet)));
1649 if (comp && comp->enabled) {
1650 sshbuf_reset(state->compression_buffer);
1651 if ((r = uncompress_buffer(ssh, state->incoming_packet,
1652 state->compression_buffer)) != 0)
1653 goto out;
1654 sshbuf_reset(state->incoming_packet);
1655 if ((r = sshbuf_putb(state->incoming_packet,
1656 state->compression_buffer)) != 0)
1657 goto out;
1658 DBG(debug("input: len after de-compress %zd",
1659 sshbuf_len(state->incoming_packet)));
1660 }
1661 /*
1662 * get packet type, implies consume.
1663 * return length of payload (without type field)
1664 */
1665 if ((r = sshbuf_get_u8(state->incoming_packet, typep)) != 0)
1666 goto out;
1667 if (ssh_packet_log_type(*typep))
1668 debug3("receive packet: type %u", *typep);
1669 if (*typep < SSH2_MSG_MIN || *typep >= SSH2_MSG_LOCAL_MIN) {
1670 if ((r = sshpkt_disconnect(ssh,
1671 "Invalid ssh2 packet type: %d", *typep)) != 0 ||
1672 (r = ssh_packet_write_wait(ssh)) < 0)
1673 return r;
1674 return SSH_ERR_PROTOCOL_ERROR;
1675 }
1676 if (state->hook_in != NULL &&
1677 (r = state->hook_in(ssh, state->incoming_packet, typep,
1678 state->hook_in_ctx)) != 0)
1679 return r;
1680 if (*typep == SSH2_MSG_USERAUTH_SUCCESS && !state->server_side)
1681 r = ssh_packet_enable_delayed_compress(ssh);
1682 else
1683 r = 0;
1684 #ifdef PACKET_DEBUG
1685 fprintf(stderr, "read/plain[%d]:\r\n", *typep);
1686 sshbuf_dump(state->incoming_packet, stderr);
1687 #endif
1688 /* reset for next packet */
1689 state->packlen = 0;
1690
1691 if ((r = ssh_packet_check_rekey(ssh)) != 0)
1692 return r;
1693 out:
1694 return r;
1695 }
1696
1697 int
ssh_packet_read_poll_seqnr(struct ssh * ssh,u_char * typep,u_int32_t * seqnr_p)1698 ssh_packet_read_poll_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
1699 {
1700 struct session_state *state = ssh->state;
1701 u_int reason, seqnr;
1702 int r;
1703 u_char *msg;
1704
1705 for (;;) {
1706 msg = NULL;
1707 r = ssh_packet_read_poll2(ssh, typep, seqnr_p);
1708 if (r != 0)
1709 return r;
1710 if (*typep) {
1711 state->keep_alive_timeouts = 0;
1712 DBG(debug("received packet type %d", *typep));
1713 }
1714 switch (*typep) {
1715 case SSH2_MSG_IGNORE:
1716 debug3("Received SSH2_MSG_IGNORE");
1717 break;
1718 case SSH2_MSG_DEBUG:
1719 if ((r = sshpkt_get_u8(ssh, NULL)) != 0 ||
1720 (r = sshpkt_get_string(ssh, &msg, NULL)) != 0 ||
1721 (r = sshpkt_get_string(ssh, NULL, NULL)) != 0) {
1722 free(msg);
1723 return r;
1724 }
1725 debug("Remote: %.900s", msg);
1726 free(msg);
1727 break;
1728 case SSH2_MSG_DISCONNECT:
1729 if ((r = sshpkt_get_u32(ssh, &reason)) != 0 ||
1730 (r = sshpkt_get_string(ssh, &msg, NULL)) != 0)
1731 return r;
1732 /* Ignore normal client exit notifications */
1733 do_log2(ssh->state->server_side &&
1734 reason == SSH2_DISCONNECT_BY_APPLICATION ?
1735 SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_ERROR,
1736 "Received disconnect from %s port %d:"
1737 "%u: %.400s", ssh_remote_ipaddr(ssh),
1738 ssh_remote_port(ssh), reason, msg);
1739 free(msg);
1740 return SSH_ERR_DISCONNECTED;
1741 case SSH2_MSG_UNIMPLEMENTED:
1742 if ((r = sshpkt_get_u32(ssh, &seqnr)) != 0)
1743 return r;
1744 debug("Received SSH2_MSG_UNIMPLEMENTED for %u",
1745 seqnr);
1746 break;
1747 default:
1748 return 0;
1749 }
1750 }
1751 }
1752
1753 /*
1754 * Buffers the supplied input data. This is intended to be used together
1755 * with packet_read_poll().
1756 */
1757 int
ssh_packet_process_incoming(struct ssh * ssh,const char * buf,u_int len)1758 ssh_packet_process_incoming(struct ssh *ssh, const char *buf, u_int len)
1759 {
1760 struct session_state *state = ssh->state;
1761 int r;
1762
1763 if (state->packet_discard) {
1764 state->keep_alive_timeouts = 0; /* ?? */
1765 if (len >= state->packet_discard) {
1766 if ((r = ssh_packet_stop_discard(ssh)) != 0)
1767 return r;
1768 }
1769 state->packet_discard -= len;
1770 return 0;
1771 }
1772 if ((r = sshbuf_put(state->input, buf, len)) != 0)
1773 return r;
1774
1775 return 0;
1776 }
1777
1778 /* Reads and buffers data from the specified fd */
1779 int
ssh_packet_process_read(struct ssh * ssh,int fd)1780 ssh_packet_process_read(struct ssh *ssh, int fd)
1781 {
1782 struct session_state *state = ssh->state;
1783 int r;
1784 size_t rlen;
1785
1786 if ((r = sshbuf_read(fd, state->input, PACKET_MAX_SIZE, &rlen)) != 0)
1787 return r;
1788
1789 if (state->packet_discard) {
1790 if ((r = sshbuf_consume_end(state->input, rlen)) != 0)
1791 return r;
1792 state->keep_alive_timeouts = 0; /* ?? */
1793 if (rlen >= state->packet_discard) {
1794 if ((r = ssh_packet_stop_discard(ssh)) != 0)
1795 return r;
1796 }
1797 state->packet_discard -= rlen;
1798 return 0;
1799 }
1800 return 0;
1801 }
1802
1803 int
ssh_packet_remaining(struct ssh * ssh)1804 ssh_packet_remaining(struct ssh *ssh)
1805 {
1806 return sshbuf_len(ssh->state->incoming_packet);
1807 }
1808
1809 /*
1810 * Sends a diagnostic message from the server to the client. This message
1811 * can be sent at any time (but not while constructing another message). The
1812 * message is printed immediately, but only if the client is being executed
1813 * in verbose mode. These messages are primarily intended to ease debugging
1814 * authentication problems. The length of the formatted message must not
1815 * exceed 1024 bytes. This will automatically call ssh_packet_write_wait.
1816 */
1817 void __attribute__((__format__ (__printf__, 2, 3)))
ssh_packet_send_debug(struct ssh * ssh,const char * fmt,...)1818 ssh_packet_send_debug(struct ssh *ssh, const char *fmt,...)
1819 {
1820 char buf[1024];
1821 va_list args;
1822 int r;
1823
1824 if ((ssh->compat & SSH_BUG_DEBUG))
1825 return;
1826
1827 va_start(args, fmt);
1828 vsnprintf(buf, sizeof(buf), fmt, args);
1829 va_end(args);
1830
1831 debug3("sending debug message: %s", buf);
1832
1833 if ((r = sshpkt_start(ssh, SSH2_MSG_DEBUG)) != 0 ||
1834 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* always display */
1835 (r = sshpkt_put_cstring(ssh, buf)) != 0 ||
1836 (r = sshpkt_put_cstring(ssh, "")) != 0 ||
1837 (r = sshpkt_send(ssh)) != 0 ||
1838 (r = ssh_packet_write_wait(ssh)) < 0)
1839 fatal_fr(r, "send DEBUG");
1840 }
1841
1842 void
sshpkt_fmt_connection_id(struct ssh * ssh,char * s,size_t l)1843 sshpkt_fmt_connection_id(struct ssh *ssh, char *s, size_t l)
1844 {
1845 snprintf(s, l, "%.200s%s%s port %d",
1846 ssh->log_preamble ? ssh->log_preamble : "",
1847 ssh->log_preamble ? " " : "",
1848 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
1849 }
1850
1851 /*
1852 * Pretty-print connection-terminating errors and exit.
1853 */
1854 static void __attribute__((__format__ (__printf__, 3, 0)))
1855 __attribute__((__noreturn__))
sshpkt_vfatal(struct ssh * ssh,int r,const char * fmt,va_list ap)1856 sshpkt_vfatal(struct ssh *ssh, int r, const char *fmt, va_list ap)
1857 {
1858 char *tag = NULL, remote_id[512];
1859 int oerrno = errno;
1860
1861 sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id));
1862
1863 switch (r) {
1864 case SSH_ERR_CONN_CLOSED:
1865 ssh_packet_clear_keys(ssh);
1866 logdie("Connection closed by %s", remote_id);
1867 case SSH_ERR_CONN_TIMEOUT:
1868 ssh_packet_clear_keys(ssh);
1869 logdie("Connection %s %s timed out",
1870 ssh->state->server_side ? "from" : "to", remote_id);
1871 case SSH_ERR_DISCONNECTED:
1872 ssh_packet_clear_keys(ssh);
1873 logdie("Disconnected from %s", remote_id);
1874 case SSH_ERR_SYSTEM_ERROR:
1875 if (errno == ECONNRESET) {
1876 ssh_packet_clear_keys(ssh);
1877 logdie("Connection reset by %s", remote_id);
1878 }
1879 /* FALLTHROUGH */
1880 case SSH_ERR_NO_CIPHER_ALG_MATCH:
1881 case SSH_ERR_NO_MAC_ALG_MATCH:
1882 case SSH_ERR_NO_COMPRESS_ALG_MATCH:
1883 case SSH_ERR_NO_KEX_ALG_MATCH:
1884 case SSH_ERR_NO_HOSTKEY_ALG_MATCH:
1885 if (ssh && ssh->kex && ssh->kex->failed_choice) {
1886 ssh_packet_clear_keys(ssh);
1887 errno = oerrno;
1888 logdie("Unable to negotiate with %s: %s. "
1889 "Their offer: %s", remote_id, ssh_err(r),
1890 ssh->kex->failed_choice);
1891 }
1892 /* FALLTHROUGH */
1893 default:
1894 if (vasprintf(&tag, fmt, ap) == -1) {
1895 ssh_packet_clear_keys(ssh);
1896 logdie_f("could not allocate failure message");
1897 }
1898 ssh_packet_clear_keys(ssh);
1899 errno = oerrno;
1900 logdie_r(r, "%s%sConnection %s %s",
1901 tag != NULL ? tag : "", tag != NULL ? ": " : "",
1902 ssh->state->server_side ? "from" : "to", remote_id);
1903 }
1904 }
1905
1906 void __attribute__((__format__ (__printf__, 3, 4)))
1907 __attribute__((__noreturn__))
sshpkt_fatal(struct ssh * ssh,int r,const char * fmt,...)1908 sshpkt_fatal(struct ssh *ssh, int r, const char *fmt, ...)
1909 {
1910 va_list ap;
1911
1912 va_start(ap, fmt);
1913 sshpkt_vfatal(ssh, r, fmt, ap);
1914 /* NOTREACHED */
1915 va_end(ap);
1916 logdie_f("should have exited");
1917 }
1918
1919 /*
1920 * Logs the error plus constructs and sends a disconnect packet, closes the
1921 * connection, and exits. This function never returns. The error message
1922 * should not contain a newline. The length of the formatted message must
1923 * not exceed 1024 bytes.
1924 */
1925 void
ssh_packet_disconnect(struct ssh * ssh,const char * fmt,...)1926 ssh_packet_disconnect(struct ssh *ssh, const char *fmt,...)
1927 {
1928 char buf[1024], remote_id[512];
1929 va_list args;
1930 static int disconnecting = 0;
1931 int r;
1932
1933 if (disconnecting) /* Guard against recursive invocations. */
1934 fatal("packet_disconnect called recursively.");
1935 disconnecting = 1;
1936
1937 /*
1938 * Format the message. Note that the caller must make sure the
1939 * message is of limited size.
1940 */
1941 sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id));
1942 va_start(args, fmt);
1943 vsnprintf(buf, sizeof(buf), fmt, args);
1944 va_end(args);
1945
1946 /* Display the error locally */
1947 logit("Disconnecting %s: %.100s", remote_id, buf);
1948
1949 /*
1950 * Send the disconnect message to the other side, and wait
1951 * for it to get sent.
1952 */
1953 if ((r = sshpkt_disconnect(ssh, "%s", buf)) != 0)
1954 sshpkt_fatal(ssh, r, "%s", __func__);
1955
1956 if ((r = ssh_packet_write_wait(ssh)) < 0)
1957 sshpkt_fatal(ssh, r, "%s", __func__);
1958
1959 /* Close the connection. */
1960 ssh_packet_close(ssh);
1961 cleanup_exit(254);
1962 }
1963
1964 /*
1965 * Checks if there is any buffered output, and tries to write some of
1966 * the output.
1967 */
1968 int
ssh_packet_write_poll(struct ssh * ssh)1969 ssh_packet_write_poll(struct ssh *ssh)
1970 {
1971 struct session_state *state = ssh->state;
1972 int len = sshbuf_len(state->output);
1973 int r;
1974
1975 if (len > 0) {
1976 len = write(state->connection_out,
1977 sshbuf_ptr(state->output), len);
1978 if (len == -1) {
1979 if (errno == EINTR || errno == EAGAIN)
1980 return 0;
1981 return SSH_ERR_SYSTEM_ERROR;
1982 }
1983 if (len == 0)
1984 return SSH_ERR_CONN_CLOSED;
1985 if ((r = sshbuf_consume(state->output, len)) < 0)
1986 return r;
1987 }
1988 return len;
1989 }
1990
1991 /*
1992 * Calls packet_write_poll repeatedly until all pending output data has been
1993 * written.
1994 */
1995 int
ssh_packet_write_wait(struct ssh * ssh)1996 ssh_packet_write_wait(struct ssh *ssh)
1997 {
1998 int ret, r, ms_remain = 0;
1999 u_int bytes_sent = 0;
2000 struct timeval start;
2001 struct timespec timespec, *timespecp = NULL;
2002 struct session_state *state = ssh->state;
2003 struct pollfd pfd;
2004
2005 if ((r = ssh_packet_write_poll(ssh)) < 0)
2006 return r;
2007 bytes_sent += r;
2008
2009 while (ssh_packet_have_data_to_write(ssh)) {
2010 pfd.fd = state->connection_out;
2011 pfd.events = POLLOUT;
2012
2013 if (state->packet_timeout_ms > 0) {
2014 ms_remain = state->packet_timeout_ms;
2015 timespecp = ×pec;
2016 }
2017 for (;;) {
2018 if (state->packet_timeout_ms > 0) {
2019 ms_to_timespec(×pec, ms_remain);
2020 monotime_tv(&start);
2021 }
2022 if ((ret = ppoll(&pfd, 1, timespecp, NULL)) >= 0)
2023 break;
2024 if (errno != EAGAIN && errno != EINTR)
2025 break;
2026 if (state->packet_timeout_ms <= 0)
2027 continue;
2028 ms_subtract_diff(&start, &ms_remain);
2029 if (ms_remain <= 0) {
2030 ret = 0;
2031 break;
2032 }
2033 }
2034 if (ret == 0)
2035 return SSH_ERR_CONN_TIMEOUT;
2036 if ((r = ssh_packet_write_poll(ssh)) < 0)
2037 return r;
2038 bytes_sent += r;
2039 }
2040 return bytes_sent;
2041 }
2042
2043 /* Returns true if there is buffered data to write to the connection. */
2044
2045 int
ssh_packet_have_data_to_write(struct ssh * ssh)2046 ssh_packet_have_data_to_write(struct ssh *ssh)
2047 {
2048 return sshbuf_len(ssh->state->output) != 0;
2049 }
2050
2051 /* Returns true if there is not too much data to write to the connection. */
2052
2053 int
ssh_packet_not_very_much_data_to_write(struct ssh * ssh)2054 ssh_packet_not_very_much_data_to_write(struct ssh *ssh)
2055 {
2056 if (ssh->state->interactive_mode)
2057 return sshbuf_len(ssh->state->output) < 16384;
2058 else
2059 return sshbuf_len(ssh->state->output) < 128 * 1024;
2060 }
2061
2062 void
ssh_packet_set_tos(struct ssh * ssh,int tos)2063 ssh_packet_set_tos(struct ssh *ssh, int tos)
2064 {
2065 if (!ssh_packet_connection_is_on_socket(ssh) || tos == INT_MAX)
2066 return;
2067 set_sock_tos(ssh->state->connection_in, tos);
2068 }
2069
2070 /* Informs that the current session is interactive. Sets IP flags for that. */
2071
2072 void
ssh_packet_set_interactive(struct ssh * ssh,int interactive,int qos_interactive,int qos_bulk)2073 ssh_packet_set_interactive(struct ssh *ssh, int interactive, int qos_interactive, int qos_bulk)
2074 {
2075 struct session_state *state = ssh->state;
2076
2077 if (state->set_interactive_called)
2078 return;
2079 state->set_interactive_called = 1;
2080
2081 /* Record that we are in interactive mode. */
2082 state->interactive_mode = interactive;
2083
2084 /* Only set socket options if using a socket. */
2085 if (!ssh_packet_connection_is_on_socket(ssh))
2086 return;
2087 set_nodelay(state->connection_in);
2088 ssh_packet_set_tos(ssh, interactive ? qos_interactive : qos_bulk);
2089 }
2090
2091 /* Returns true if the current connection is interactive. */
2092
2093 int
ssh_packet_is_interactive(struct ssh * ssh)2094 ssh_packet_is_interactive(struct ssh *ssh)
2095 {
2096 return ssh->state->interactive_mode;
2097 }
2098
2099 int
ssh_packet_set_maxsize(struct ssh * ssh,u_int s)2100 ssh_packet_set_maxsize(struct ssh *ssh, u_int s)
2101 {
2102 struct session_state *state = ssh->state;
2103
2104 if (state->set_maxsize_called) {
2105 logit_f("called twice: old %d new %d",
2106 state->max_packet_size, s);
2107 return -1;
2108 }
2109 if (s < 4 * 1024 || s > 1024 * 1024) {
2110 logit_f("bad size %d", s);
2111 return -1;
2112 }
2113 state->set_maxsize_called = 1;
2114 debug_f("setting to %d", s);
2115 state->max_packet_size = s;
2116 return s;
2117 }
2118
2119 int
ssh_packet_inc_alive_timeouts(struct ssh * ssh)2120 ssh_packet_inc_alive_timeouts(struct ssh *ssh)
2121 {
2122 return ++ssh->state->keep_alive_timeouts;
2123 }
2124
2125 void
ssh_packet_set_alive_timeouts(struct ssh * ssh,int ka)2126 ssh_packet_set_alive_timeouts(struct ssh *ssh, int ka)
2127 {
2128 ssh->state->keep_alive_timeouts = ka;
2129 }
2130
2131 u_int
ssh_packet_get_maxsize(struct ssh * ssh)2132 ssh_packet_get_maxsize(struct ssh *ssh)
2133 {
2134 return ssh->state->max_packet_size;
2135 }
2136
2137 void
ssh_packet_set_rekey_limits(struct ssh * ssh,u_int64_t bytes,u_int32_t seconds)2138 ssh_packet_set_rekey_limits(struct ssh *ssh, u_int64_t bytes, u_int32_t seconds)
2139 {
2140 debug3("rekey after %llu bytes, %u seconds", (unsigned long long)bytes,
2141 (unsigned int)seconds);
2142 ssh->state->rekey_limit = bytes;
2143 ssh->state->rekey_interval = seconds;
2144 }
2145
2146 time_t
ssh_packet_get_rekey_timeout(struct ssh * ssh)2147 ssh_packet_get_rekey_timeout(struct ssh *ssh)
2148 {
2149 time_t seconds;
2150
2151 seconds = ssh->state->rekey_time + ssh->state->rekey_interval -
2152 monotime();
2153 return (seconds <= 0 ? 1 : seconds);
2154 }
2155
2156 void
ssh_packet_set_server(struct ssh * ssh)2157 ssh_packet_set_server(struct ssh *ssh)
2158 {
2159 ssh->state->server_side = 1;
2160 ssh->kex->server = 1; /* XXX unify? */
2161 }
2162
2163 void
ssh_packet_set_authenticated(struct ssh * ssh)2164 ssh_packet_set_authenticated(struct ssh *ssh)
2165 {
2166 ssh->state->after_authentication = 1;
2167 }
2168
2169 void *
ssh_packet_get_input(struct ssh * ssh)2170 ssh_packet_get_input(struct ssh *ssh)
2171 {
2172 return (void *)ssh->state->input;
2173 }
2174
2175 void *
ssh_packet_get_output(struct ssh * ssh)2176 ssh_packet_get_output(struct ssh *ssh)
2177 {
2178 return (void *)ssh->state->output;
2179 }
2180
2181 /* Reset after_authentication and reset compression in post-auth privsep */
2182 static int
ssh_packet_set_postauth(struct ssh * ssh)2183 ssh_packet_set_postauth(struct ssh *ssh)
2184 {
2185 int r;
2186
2187 debug_f("called");
2188 /* This was set in net child, but is not visible in user child */
2189 ssh->state->after_authentication = 1;
2190 ssh->state->rekeying = 0;
2191 if ((r = ssh_packet_enable_delayed_compress(ssh)) != 0)
2192 return r;
2193 return 0;
2194 }
2195
2196 /* Packet state (de-)serialization for privsep */
2197
2198 /* turn kex into a blob for packet state serialization */
2199 static int
kex_to_blob(struct sshbuf * m,struct kex * kex)2200 kex_to_blob(struct sshbuf *m, struct kex *kex)
2201 {
2202 int r;
2203
2204 if ((r = sshbuf_put_u32(m, kex->we_need)) != 0 ||
2205 (r = sshbuf_put_cstring(m, kex->hostkey_alg)) != 0 ||
2206 (r = sshbuf_put_u32(m, kex->hostkey_type)) != 0 ||
2207 (r = sshbuf_put_u32(m, kex->hostkey_nid)) != 0 ||
2208 (r = sshbuf_put_u32(m, kex->kex_type)) != 0 ||
2209 (r = sshbuf_put_stringb(m, kex->my)) != 0 ||
2210 (r = sshbuf_put_stringb(m, kex->peer)) != 0 ||
2211 (r = sshbuf_put_stringb(m, kex->client_version)) != 0 ||
2212 (r = sshbuf_put_stringb(m, kex->server_version)) != 0 ||
2213 (r = sshbuf_put_stringb(m, kex->session_id)) != 0 ||
2214 (r = sshbuf_put_u32(m, kex->flags)) != 0)
2215 return r;
2216 return 0;
2217 }
2218
2219 /* turn key exchange results into a blob for packet state serialization */
2220 static int
newkeys_to_blob(struct sshbuf * m,struct ssh * ssh,int mode)2221 newkeys_to_blob(struct sshbuf *m, struct ssh *ssh, int mode)
2222 {
2223 struct sshbuf *b;
2224 struct sshcipher_ctx *cc;
2225 struct sshcomp *comp;
2226 struct sshenc *enc;
2227 struct sshmac *mac;
2228 struct newkeys *newkey;
2229 int r;
2230
2231 if ((newkey = ssh->state->newkeys[mode]) == NULL)
2232 return SSH_ERR_INTERNAL_ERROR;
2233 enc = &newkey->enc;
2234 mac = &newkey->mac;
2235 comp = &newkey->comp;
2236 cc = (mode == MODE_OUT) ? ssh->state->send_context :
2237 ssh->state->receive_context;
2238 if ((r = cipher_get_keyiv(cc, enc->iv, enc->iv_len)) != 0)
2239 return r;
2240 if ((b = sshbuf_new()) == NULL)
2241 return SSH_ERR_ALLOC_FAIL;
2242 if ((r = sshbuf_put_cstring(b, enc->name)) != 0 ||
2243 (r = sshbuf_put_u32(b, enc->enabled)) != 0 ||
2244 (r = sshbuf_put_u32(b, enc->block_size)) != 0 ||
2245 (r = sshbuf_put_string(b, enc->key, enc->key_len)) != 0 ||
2246 (r = sshbuf_put_string(b, enc->iv, enc->iv_len)) != 0)
2247 goto out;
2248 if (cipher_authlen(enc->cipher) == 0) {
2249 if ((r = sshbuf_put_cstring(b, mac->name)) != 0 ||
2250 (r = sshbuf_put_u32(b, mac->enabled)) != 0 ||
2251 (r = sshbuf_put_string(b, mac->key, mac->key_len)) != 0)
2252 goto out;
2253 }
2254 if ((r = sshbuf_put_u32(b, comp->type)) != 0 ||
2255 (r = sshbuf_put_cstring(b, comp->name)) != 0)
2256 goto out;
2257 r = sshbuf_put_stringb(m, b);
2258 out:
2259 sshbuf_free(b);
2260 return r;
2261 }
2262
2263 /* serialize packet state into a blob */
2264 int
ssh_packet_get_state(struct ssh * ssh,struct sshbuf * m)2265 ssh_packet_get_state(struct ssh *ssh, struct sshbuf *m)
2266 {
2267 struct session_state *state = ssh->state;
2268 int r;
2269
2270 if ((r = kex_to_blob(m, ssh->kex)) != 0 ||
2271 (r = newkeys_to_blob(m, ssh, MODE_OUT)) != 0 ||
2272 (r = newkeys_to_blob(m, ssh, MODE_IN)) != 0 ||
2273 (r = sshbuf_put_u64(m, state->rekey_limit)) != 0 ||
2274 (r = sshbuf_put_u32(m, state->rekey_interval)) != 0 ||
2275 (r = sshbuf_put_u32(m, state->p_send.seqnr)) != 0 ||
2276 (r = sshbuf_put_u64(m, state->p_send.blocks)) != 0 ||
2277 (r = sshbuf_put_u32(m, state->p_send.packets)) != 0 ||
2278 (r = sshbuf_put_u64(m, state->p_send.bytes)) != 0 ||
2279 (r = sshbuf_put_u32(m, state->p_read.seqnr)) != 0 ||
2280 (r = sshbuf_put_u64(m, state->p_read.blocks)) != 0 ||
2281 (r = sshbuf_put_u32(m, state->p_read.packets)) != 0 ||
2282 (r = sshbuf_put_u64(m, state->p_read.bytes)) != 0 ||
2283 (r = sshbuf_put_stringb(m, state->input)) != 0 ||
2284 (r = sshbuf_put_stringb(m, state->output)) != 0)
2285 return r;
2286
2287 return 0;
2288 }
2289
2290 /* restore key exchange results from blob for packet state de-serialization */
2291 static int
newkeys_from_blob(struct sshbuf * m,struct ssh * ssh,int mode)2292 newkeys_from_blob(struct sshbuf *m, struct ssh *ssh, int mode)
2293 {
2294 struct sshbuf *b = NULL;
2295 struct sshcomp *comp;
2296 struct sshenc *enc;
2297 struct sshmac *mac;
2298 struct newkeys *newkey = NULL;
2299 size_t keylen, ivlen, maclen;
2300 int r;
2301
2302 if ((newkey = calloc(1, sizeof(*newkey))) == NULL) {
2303 r = SSH_ERR_ALLOC_FAIL;
2304 goto out;
2305 }
2306 if ((r = sshbuf_froms(m, &b)) != 0)
2307 goto out;
2308 #ifdef DEBUG_PK
2309 sshbuf_dump(b, stderr);
2310 #endif
2311 enc = &newkey->enc;
2312 mac = &newkey->mac;
2313 comp = &newkey->comp;
2314
2315 if ((r = sshbuf_get_cstring(b, &enc->name, NULL)) != 0 ||
2316 (r = sshbuf_get_u32(b, (u_int *)&enc->enabled)) != 0 ||
2317 (r = sshbuf_get_u32(b, &enc->block_size)) != 0 ||
2318 (r = sshbuf_get_string(b, &enc->key, &keylen)) != 0 ||
2319 (r = sshbuf_get_string(b, &enc->iv, &ivlen)) != 0)
2320 goto out;
2321 if ((enc->cipher = cipher_by_name(enc->name)) == NULL) {
2322 r = SSH_ERR_INVALID_FORMAT;
2323 goto out;
2324 }
2325 if (cipher_authlen(enc->cipher) == 0) {
2326 if ((r = sshbuf_get_cstring(b, &mac->name, NULL)) != 0)
2327 goto out;
2328 if ((r = mac_setup(mac, mac->name)) != 0)
2329 goto out;
2330 if ((r = sshbuf_get_u32(b, (u_int *)&mac->enabled)) != 0 ||
2331 (r = sshbuf_get_string(b, &mac->key, &maclen)) != 0)
2332 goto out;
2333 if (maclen > mac->key_len) {
2334 r = SSH_ERR_INVALID_FORMAT;
2335 goto out;
2336 }
2337 mac->key_len = maclen;
2338 }
2339 if ((r = sshbuf_get_u32(b, &comp->type)) != 0 ||
2340 (r = sshbuf_get_cstring(b, &comp->name, NULL)) != 0)
2341 goto out;
2342 if (sshbuf_len(b) != 0) {
2343 r = SSH_ERR_INVALID_FORMAT;
2344 goto out;
2345 }
2346 enc->key_len = keylen;
2347 enc->iv_len = ivlen;
2348 ssh->kex->newkeys[mode] = newkey;
2349 newkey = NULL;
2350 r = 0;
2351 out:
2352 free(newkey);
2353 sshbuf_free(b);
2354 return r;
2355 }
2356
2357 /* restore kex from blob for packet state de-serialization */
2358 static int
kex_from_blob(struct sshbuf * m,struct kex ** kexp)2359 kex_from_blob(struct sshbuf *m, struct kex **kexp)
2360 {
2361 struct kex *kex;
2362 int r;
2363
2364 if ((kex = kex_new()) == NULL)
2365 return SSH_ERR_ALLOC_FAIL;
2366 if ((r = sshbuf_get_u32(m, &kex->we_need)) != 0 ||
2367 (r = sshbuf_get_cstring(m, &kex->hostkey_alg, NULL)) != 0 ||
2368 (r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_type)) != 0 ||
2369 (r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_nid)) != 0 ||
2370 (r = sshbuf_get_u32(m, &kex->kex_type)) != 0 ||
2371 (r = sshbuf_get_stringb(m, kex->my)) != 0 ||
2372 (r = sshbuf_get_stringb(m, kex->peer)) != 0 ||
2373 (r = sshbuf_get_stringb(m, kex->client_version)) != 0 ||
2374 (r = sshbuf_get_stringb(m, kex->server_version)) != 0 ||
2375 (r = sshbuf_get_stringb(m, kex->session_id)) != 0 ||
2376 (r = sshbuf_get_u32(m, &kex->flags)) != 0)
2377 goto out;
2378 kex->server = 1;
2379 kex->done = 1;
2380 r = 0;
2381 out:
2382 if (r != 0 || kexp == NULL) {
2383 kex_free(kex);
2384 if (kexp != NULL)
2385 *kexp = NULL;
2386 } else {
2387 kex_free(*kexp);
2388 *kexp = kex;
2389 }
2390 return r;
2391 }
2392
2393 /*
2394 * Restore packet state from content of blob 'm' (de-serialization).
2395 * Note that 'm' will be partially consumed on parsing or any other errors.
2396 */
2397 int
ssh_packet_set_state(struct ssh * ssh,struct sshbuf * m)2398 ssh_packet_set_state(struct ssh *ssh, struct sshbuf *m)
2399 {
2400 struct session_state *state = ssh->state;
2401 const u_char *input, *output;
2402 size_t ilen, olen;
2403 int r;
2404
2405 if ((r = kex_from_blob(m, &ssh->kex)) != 0 ||
2406 (r = newkeys_from_blob(m, ssh, MODE_OUT)) != 0 ||
2407 (r = newkeys_from_blob(m, ssh, MODE_IN)) != 0 ||
2408 (r = sshbuf_get_u64(m, &state->rekey_limit)) != 0 ||
2409 (r = sshbuf_get_u32(m, &state->rekey_interval)) != 0 ||
2410 (r = sshbuf_get_u32(m, &state->p_send.seqnr)) != 0 ||
2411 (r = sshbuf_get_u64(m, &state->p_send.blocks)) != 0 ||
2412 (r = sshbuf_get_u32(m, &state->p_send.packets)) != 0 ||
2413 (r = sshbuf_get_u64(m, &state->p_send.bytes)) != 0 ||
2414 (r = sshbuf_get_u32(m, &state->p_read.seqnr)) != 0 ||
2415 (r = sshbuf_get_u64(m, &state->p_read.blocks)) != 0 ||
2416 (r = sshbuf_get_u32(m, &state->p_read.packets)) != 0 ||
2417 (r = sshbuf_get_u64(m, &state->p_read.bytes)) != 0)
2418 return r;
2419 /*
2420 * We set the time here so that in post-auth privsep child we
2421 * count from the completion of the authentication.
2422 */
2423 state->rekey_time = monotime();
2424 /* XXX ssh_set_newkeys overrides p_read.packets? XXX */
2425 if ((r = ssh_set_newkeys(ssh, MODE_IN)) != 0 ||
2426 (r = ssh_set_newkeys(ssh, MODE_OUT)) != 0)
2427 return r;
2428
2429 if ((r = ssh_packet_set_postauth(ssh)) != 0)
2430 return r;
2431
2432 sshbuf_reset(state->input);
2433 sshbuf_reset(state->output);
2434 if ((r = sshbuf_get_string_direct(m, &input, &ilen)) != 0 ||
2435 (r = sshbuf_get_string_direct(m, &output, &olen)) != 0 ||
2436 (r = sshbuf_put(state->input, input, ilen)) != 0 ||
2437 (r = sshbuf_put(state->output, output, olen)) != 0)
2438 return r;
2439
2440 if (sshbuf_len(m))
2441 return SSH_ERR_INVALID_FORMAT;
2442 debug3_f("done");
2443 return 0;
2444 }
2445
2446 /* NEW API */
2447
2448 /* put data to the outgoing packet */
2449
2450 int
sshpkt_put(struct ssh * ssh,const void * v,size_t len)2451 sshpkt_put(struct ssh *ssh, const void *v, size_t len)
2452 {
2453 return sshbuf_put(ssh->state->outgoing_packet, v, len);
2454 }
2455
2456 int
sshpkt_putb(struct ssh * ssh,const struct sshbuf * b)2457 sshpkt_putb(struct ssh *ssh, const struct sshbuf *b)
2458 {
2459 return sshbuf_putb(ssh->state->outgoing_packet, b);
2460 }
2461
2462 int
sshpkt_put_u8(struct ssh * ssh,u_char val)2463 sshpkt_put_u8(struct ssh *ssh, u_char val)
2464 {
2465 return sshbuf_put_u8(ssh->state->outgoing_packet, val);
2466 }
2467
2468 int
sshpkt_put_u32(struct ssh * ssh,u_int32_t val)2469 sshpkt_put_u32(struct ssh *ssh, u_int32_t val)
2470 {
2471 return sshbuf_put_u32(ssh->state->outgoing_packet, val);
2472 }
2473
2474 int
sshpkt_put_u64(struct ssh * ssh,u_int64_t val)2475 sshpkt_put_u64(struct ssh *ssh, u_int64_t val)
2476 {
2477 return sshbuf_put_u64(ssh->state->outgoing_packet, val);
2478 }
2479
2480 int
sshpkt_put_string(struct ssh * ssh,const void * v,size_t len)2481 sshpkt_put_string(struct ssh *ssh, const void *v, size_t len)
2482 {
2483 return sshbuf_put_string(ssh->state->outgoing_packet, v, len);
2484 }
2485
2486 int
sshpkt_put_cstring(struct ssh * ssh,const void * v)2487 sshpkt_put_cstring(struct ssh *ssh, const void *v)
2488 {
2489 return sshbuf_put_cstring(ssh->state->outgoing_packet, v);
2490 }
2491
2492 int
sshpkt_put_stringb(struct ssh * ssh,const struct sshbuf * v)2493 sshpkt_put_stringb(struct ssh *ssh, const struct sshbuf *v)
2494 {
2495 return sshbuf_put_stringb(ssh->state->outgoing_packet, v);
2496 }
2497
2498 #ifdef WITH_OPENSSL
2499 int
sshpkt_put_ec(struct ssh * ssh,const EC_POINT * v,const EC_GROUP * g)2500 sshpkt_put_ec(struct ssh *ssh, const EC_POINT *v, const EC_GROUP *g)
2501 {
2502 return sshbuf_put_ec(ssh->state->outgoing_packet, v, g);
2503 }
2504
2505
2506 int
sshpkt_put_bignum2(struct ssh * ssh,const BIGNUM * v)2507 sshpkt_put_bignum2(struct ssh *ssh, const BIGNUM *v)
2508 {
2509 return sshbuf_put_bignum2(ssh->state->outgoing_packet, v);
2510 }
2511 #endif /* WITH_OPENSSL */
2512
2513 /* fetch data from the incoming packet */
2514
2515 int
sshpkt_get(struct ssh * ssh,void * valp,size_t len)2516 sshpkt_get(struct ssh *ssh, void *valp, size_t len)
2517 {
2518 return sshbuf_get(ssh->state->incoming_packet, valp, len);
2519 }
2520
2521 int
sshpkt_get_u8(struct ssh * ssh,u_char * valp)2522 sshpkt_get_u8(struct ssh *ssh, u_char *valp)
2523 {
2524 return sshbuf_get_u8(ssh->state->incoming_packet, valp);
2525 }
2526
2527 int
sshpkt_get_u32(struct ssh * ssh,u_int32_t * valp)2528 sshpkt_get_u32(struct ssh *ssh, u_int32_t *valp)
2529 {
2530 return sshbuf_get_u32(ssh->state->incoming_packet, valp);
2531 }
2532
2533 int
sshpkt_get_u64(struct ssh * ssh,u_int64_t * valp)2534 sshpkt_get_u64(struct ssh *ssh, u_int64_t *valp)
2535 {
2536 return sshbuf_get_u64(ssh->state->incoming_packet, valp);
2537 }
2538
2539 int
sshpkt_get_string(struct ssh * ssh,u_char ** valp,size_t * lenp)2540 sshpkt_get_string(struct ssh *ssh, u_char **valp, size_t *lenp)
2541 {
2542 return sshbuf_get_string(ssh->state->incoming_packet, valp, lenp);
2543 }
2544
2545 int
sshpkt_get_string_direct(struct ssh * ssh,const u_char ** valp,size_t * lenp)2546 sshpkt_get_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp)
2547 {
2548 return sshbuf_get_string_direct(ssh->state->incoming_packet, valp, lenp);
2549 }
2550
2551 int
sshpkt_peek_string_direct(struct ssh * ssh,const u_char ** valp,size_t * lenp)2552 sshpkt_peek_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp)
2553 {
2554 return sshbuf_peek_string_direct(ssh->state->incoming_packet, valp, lenp);
2555 }
2556
2557 int
sshpkt_get_cstring(struct ssh * ssh,char ** valp,size_t * lenp)2558 sshpkt_get_cstring(struct ssh *ssh, char **valp, size_t *lenp)
2559 {
2560 return sshbuf_get_cstring(ssh->state->incoming_packet, valp, lenp);
2561 }
2562
2563 int
sshpkt_getb_froms(struct ssh * ssh,struct sshbuf ** valp)2564 sshpkt_getb_froms(struct ssh *ssh, struct sshbuf **valp)
2565 {
2566 return sshbuf_froms(ssh->state->incoming_packet, valp);
2567 }
2568
2569 #ifdef WITH_OPENSSL
2570 int
sshpkt_get_ec(struct ssh * ssh,EC_POINT * v,const EC_GROUP * g)2571 sshpkt_get_ec(struct ssh *ssh, EC_POINT *v, const EC_GROUP *g)
2572 {
2573 return sshbuf_get_ec(ssh->state->incoming_packet, v, g);
2574 }
2575
2576 int
sshpkt_get_bignum2(struct ssh * ssh,BIGNUM ** valp)2577 sshpkt_get_bignum2(struct ssh *ssh, BIGNUM **valp)
2578 {
2579 return sshbuf_get_bignum2(ssh->state->incoming_packet, valp);
2580 }
2581 #endif /* WITH_OPENSSL */
2582
2583 int
sshpkt_get_end(struct ssh * ssh)2584 sshpkt_get_end(struct ssh *ssh)
2585 {
2586 if (sshbuf_len(ssh->state->incoming_packet) > 0)
2587 return SSH_ERR_UNEXPECTED_TRAILING_DATA;
2588 return 0;
2589 }
2590
2591 const u_char *
sshpkt_ptr(struct ssh * ssh,size_t * lenp)2592 sshpkt_ptr(struct ssh *ssh, size_t *lenp)
2593 {
2594 if (lenp != NULL)
2595 *lenp = sshbuf_len(ssh->state->incoming_packet);
2596 return sshbuf_ptr(ssh->state->incoming_packet);
2597 }
2598
2599 /* start a new packet */
2600
2601 int
sshpkt_start(struct ssh * ssh,u_char type)2602 sshpkt_start(struct ssh *ssh, u_char type)
2603 {
2604 u_char buf[6]; /* u32 packet length, u8 pad len, u8 type */
2605
2606 DBG(debug("packet_start[%d]", type));
2607 memset(buf, 0, sizeof(buf));
2608 buf[sizeof(buf) - 1] = type;
2609 sshbuf_reset(ssh->state->outgoing_packet);
2610 return sshbuf_put(ssh->state->outgoing_packet, buf, sizeof(buf));
2611 }
2612
2613 static int
ssh_packet_send_mux(struct ssh * ssh)2614 ssh_packet_send_mux(struct ssh *ssh)
2615 {
2616 struct session_state *state = ssh->state;
2617 u_char type, *cp;
2618 size_t len;
2619 int r;
2620
2621 if (ssh->kex)
2622 return SSH_ERR_INTERNAL_ERROR;
2623 len = sshbuf_len(state->outgoing_packet);
2624 if (len < 6)
2625 return SSH_ERR_INTERNAL_ERROR;
2626 cp = sshbuf_mutable_ptr(state->outgoing_packet);
2627 type = cp[5];
2628 if (ssh_packet_log_type(type))
2629 debug3_f("type %u", type);
2630 /* drop everything, but the connection protocol */
2631 if (type >= SSH2_MSG_CONNECTION_MIN &&
2632 type <= SSH2_MSG_CONNECTION_MAX) {
2633 POKE_U32(cp, len - 4);
2634 if ((r = sshbuf_putb(state->output,
2635 state->outgoing_packet)) != 0)
2636 return r;
2637 /* sshbuf_dump(state->output, stderr); */
2638 }
2639 sshbuf_reset(state->outgoing_packet);
2640 return 0;
2641 }
2642
2643 /*
2644 * 9.2. Ignored Data Message
2645 *
2646 * byte SSH_MSG_IGNORE
2647 * string data
2648 *
2649 * All implementations MUST understand (and ignore) this message at any
2650 * time (after receiving the protocol version). No implementation is
2651 * required to send them. This message can be used as an additional
2652 * protection measure against advanced traffic analysis techniques.
2653 */
2654 int
sshpkt_msg_ignore(struct ssh * ssh,u_int nbytes)2655 sshpkt_msg_ignore(struct ssh *ssh, u_int nbytes)
2656 {
2657 u_int32_t rnd = 0;
2658 int r;
2659 u_int i;
2660
2661 if ((r = sshpkt_start(ssh, SSH2_MSG_IGNORE)) != 0 ||
2662 (r = sshpkt_put_u32(ssh, nbytes)) != 0)
2663 return r;
2664 for (i = 0; i < nbytes; i++) {
2665 if (i % 4 == 0)
2666 rnd = arc4random();
2667 if ((r = sshpkt_put_u8(ssh, (u_char)rnd & 0xff)) != 0)
2668 return r;
2669 rnd >>= 8;
2670 }
2671 return 0;
2672 }
2673
2674 /* send it */
2675
2676 int
sshpkt_sendx(struct ssh * ssh)2677 sshpkt_sendx(struct ssh *ssh)
2678 {
2679 if (ssh->state && ssh->state->mux)
2680 return ssh_packet_send_mux(ssh);
2681 return ssh_packet_send2(ssh);
2682 }
2683
2684 int
sshpkt_send(struct ssh * ssh)2685 sshpkt_send(struct ssh *ssh)
2686 {
2687 int r = sshpkt_sendx(ssh);
2688 return r < 0 ? r : 0;
2689 }
2690
2691 int
sshpkt_disconnect(struct ssh * ssh,const char * fmt,...)2692 sshpkt_disconnect(struct ssh *ssh, const char *fmt,...)
2693 {
2694 char buf[1024];
2695 va_list args;
2696 int r;
2697
2698 va_start(args, fmt);
2699 vsnprintf(buf, sizeof(buf), fmt, args);
2700 va_end(args);
2701
2702 if ((r = sshpkt_start(ssh, SSH2_MSG_DISCONNECT)) != 0 ||
2703 (r = sshpkt_put_u32(ssh, SSH2_DISCONNECT_PROTOCOL_ERROR)) != 0 ||
2704 (r = sshpkt_put_cstring(ssh, buf)) != 0 ||
2705 (r = sshpkt_put_cstring(ssh, "")) != 0 ||
2706 (r = sshpkt_send(ssh)) != 0)
2707 return r;
2708 return 0;
2709 }
2710
2711 /* roundup current message to pad bytes */
2712 int
sshpkt_add_padding(struct ssh * ssh,u_char pad)2713 sshpkt_add_padding(struct ssh *ssh, u_char pad)
2714 {
2715 ssh->state->extra_pad = pad;
2716 return 0;
2717 }
2718
2719 int
ssh_packet_authentication_state(struct ssh * ssh)2720 ssh_packet_authentication_state(struct ssh *ssh)
2721 {
2722 return ssh->state->after_authentication;
2723 }
2724