1 /* $OpenBSD: packet.c,v 1.313 2023/12/18 14:45:17 djm Exp $ */
2 /*
3 * Author: Tatu Ylonen <ylo@cs.hut.fi>
4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * All rights reserved
6 * This file contains code implementing the packet protocol and communication
7 * with the other side. This same code is used both on client and server side.
8 *
9 * As far as I am concerned, the code I have written for this software
10 * can be used freely for any purpose. Any derived versions of this
11 * software must be clearly marked as such, and if the derived work is
12 * incompatible with the protocol description in the RFC file, it must be
13 * called by a name other than "ssh" or "Secure Shell".
14 *
15 *
16 * SSH2 packet format added by Markus Friedl.
17 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
18 *
19 * Redistribution and use in source and binary forms, with or without
20 * modification, are permitted provided that the following conditions
21 * are met:
22 * 1. Redistributions of source code must retain the above copyright
23 * notice, this list of conditions and the following disclaimer.
24 * 2. Redistributions in binary form must reproduce the above copyright
25 * notice, this list of conditions and the following disclaimer in the
26 * documentation and/or other materials provided with the distribution.
27 *
28 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
29 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
30 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
31 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
32 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
33 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
34 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
35 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
36 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
37 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
38 */
39
40 #include <sys/types.h>
41 #include <sys/queue.h>
42 #include <sys/socket.h>
43 #include <sys/time.h>
44 #include <netinet/in.h>
45 #include <netinet/ip.h>
46
47 #include <errno.h>
48 #include <netdb.h>
49 #include <stdarg.h>
50 #include <stdio.h>
51 #include <stdlib.h>
52 #include <string.h>
53 #include <unistd.h>
54 #include <limits.h>
55 #include <poll.h>
56 #include <signal.h>
57 #include <time.h>
58
59 #ifdef WITH_ZLIB
60 #include <zlib.h>
61 #endif
62
63 #include "xmalloc.h"
64 #include "compat.h"
65 #include "ssh2.h"
66 #include "cipher.h"
67 #include "sshkey.h"
68 #include "kex.h"
69 #include "digest.h"
70 #include "mac.h"
71 #include "log.h"
72 #include "canohost.h"
73 #include "misc.h"
74 #include "channels.h"
75 #include "ssh.h"
76 #include "packet.h"
77 #include "ssherr.h"
78 #include "sshbuf.h"
79
80 #ifdef PACKET_DEBUG
81 #define DBG(x) x
82 #else
83 #define DBG(x)
84 #endif
85
86 #define PACKET_MAX_SIZE (256 * 1024)
87
88 struct packet_state {
89 u_int32_t seqnr;
90 u_int32_t packets;
91 u_int64_t blocks;
92 u_int64_t bytes;
93 };
94
95 struct packet {
96 TAILQ_ENTRY(packet) next;
97 u_char type;
98 struct sshbuf *payload;
99 };
100
101 struct session_state {
102 /*
103 * This variable contains the file descriptors used for
104 * communicating with the other side. connection_in is used for
105 * reading; connection_out for writing. These can be the same
106 * descriptor, in which case it is assumed to be a socket.
107 */
108 int connection_in;
109 int connection_out;
110
111 /* Protocol flags for the remote side. */
112 u_int remote_protocol_flags;
113
114 /* Encryption context for receiving data. Only used for decryption. */
115 struct sshcipher_ctx *receive_context;
116
117 /* Encryption context for sending data. Only used for encryption. */
118 struct sshcipher_ctx *send_context;
119
120 /* Buffer for raw input data from the socket. */
121 struct sshbuf *input;
122
123 /* Buffer for raw output data going to the socket. */
124 struct sshbuf *output;
125
126 /* Buffer for the partial outgoing packet being constructed. */
127 struct sshbuf *outgoing_packet;
128
129 /* Buffer for the incoming packet currently being processed. */
130 struct sshbuf *incoming_packet;
131
132 /* Scratch buffer for packet compression/decompression. */
133 struct sshbuf *compression_buffer;
134
135 #ifdef WITH_ZLIB
136 /* Incoming/outgoing compression dictionaries */
137 z_stream compression_in_stream;
138 z_stream compression_out_stream;
139 #endif
140 int compression_in_started;
141 int compression_out_started;
142 int compression_in_failures;
143 int compression_out_failures;
144
145 /* default maximum packet size */
146 u_int max_packet_size;
147
148 /* Flag indicating whether this module has been initialized. */
149 int initialized;
150
151 /* Set to true if the connection is interactive. */
152 int interactive_mode;
153
154 /* Set to true if we are the server side. */
155 int server_side;
156
157 /* Set to true if we are authenticated. */
158 int after_authentication;
159
160 int keep_alive_timeouts;
161
162 /* The maximum time that we will wait to send or receive a packet */
163 int packet_timeout_ms;
164
165 /* Session key information for Encryption and MAC */
166 struct newkeys *newkeys[MODE_MAX];
167 struct packet_state p_read, p_send;
168
169 /* Volume-based rekeying */
170 u_int64_t max_blocks_in, max_blocks_out, rekey_limit;
171
172 /* Time-based rekeying */
173 u_int32_t rekey_interval; /* how often in seconds */
174 time_t rekey_time; /* time of last rekeying */
175
176 /* roundup current message to extra_pad bytes */
177 u_char extra_pad;
178
179 /* XXX discard incoming data after MAC error */
180 u_int packet_discard;
181 size_t packet_discard_mac_already;
182 struct sshmac *packet_discard_mac;
183
184 /* Used in packet_read_poll2() */
185 u_int packlen;
186
187 /* Used in packet_send2 */
188 int rekeying;
189
190 /* Used in ssh_packet_send_mux() */
191 int mux;
192
193 /* Used in packet_set_interactive */
194 int set_interactive_called;
195
196 /* Used in packet_set_maxsize */
197 int set_maxsize_called;
198
199 /* One-off warning about weak ciphers */
200 int cipher_warning_done;
201
202 /* Hook for fuzzing inbound packets */
203 ssh_packet_hook_fn *hook_in;
204 void *hook_in_ctx;
205
206 TAILQ_HEAD(, packet) outgoing;
207 };
208
209 struct ssh *
ssh_alloc_session_state(void)210 ssh_alloc_session_state(void)
211 {
212 struct ssh *ssh = NULL;
213 struct session_state *state = NULL;
214
215 if ((ssh = calloc(1, sizeof(*ssh))) == NULL ||
216 (state = calloc(1, sizeof(*state))) == NULL ||
217 (ssh->kex = kex_new()) == NULL ||
218 (state->input = sshbuf_new()) == NULL ||
219 (state->output = sshbuf_new()) == NULL ||
220 (state->outgoing_packet = sshbuf_new()) == NULL ||
221 (state->incoming_packet = sshbuf_new()) == NULL)
222 goto fail;
223 TAILQ_INIT(&state->outgoing);
224 TAILQ_INIT(&ssh->private_keys);
225 TAILQ_INIT(&ssh->public_keys);
226 state->connection_in = -1;
227 state->connection_out = -1;
228 state->max_packet_size = 32768;
229 state->packet_timeout_ms = -1;
230 state->p_send.packets = state->p_read.packets = 0;
231 state->initialized = 1;
232 /*
233 * ssh_packet_send2() needs to queue packets until
234 * we've done the initial key exchange.
235 */
236 state->rekeying = 1;
237 ssh->state = state;
238 return ssh;
239 fail:
240 if (ssh) {
241 kex_free(ssh->kex);
242 free(ssh);
243 }
244 if (state) {
245 sshbuf_free(state->input);
246 sshbuf_free(state->output);
247 sshbuf_free(state->incoming_packet);
248 sshbuf_free(state->outgoing_packet);
249 free(state);
250 }
251 return NULL;
252 }
253
254 void
ssh_packet_set_input_hook(struct ssh * ssh,ssh_packet_hook_fn * hook,void * ctx)255 ssh_packet_set_input_hook(struct ssh *ssh, ssh_packet_hook_fn *hook, void *ctx)
256 {
257 ssh->state->hook_in = hook;
258 ssh->state->hook_in_ctx = ctx;
259 }
260
261 /* Returns nonzero if rekeying is in progress */
262 int
ssh_packet_is_rekeying(struct ssh * ssh)263 ssh_packet_is_rekeying(struct ssh *ssh)
264 {
265 return ssh->state->rekeying ||
266 (ssh->kex != NULL && ssh->kex->done == 0);
267 }
268
269 /*
270 * Sets the descriptors used for communication.
271 */
272 struct ssh *
ssh_packet_set_connection(struct ssh * ssh,int fd_in,int fd_out)273 ssh_packet_set_connection(struct ssh *ssh, int fd_in, int fd_out)
274 {
275 struct session_state *state;
276 const struct sshcipher *none = cipher_by_name("none");
277 int r;
278
279 if (none == NULL) {
280 error_f("cannot load cipher 'none'");
281 return NULL;
282 }
283 if (ssh == NULL)
284 ssh = ssh_alloc_session_state();
285 if (ssh == NULL) {
286 error_f("could not allocate state");
287 return NULL;
288 }
289 state = ssh->state;
290 state->connection_in = fd_in;
291 state->connection_out = fd_out;
292 if ((r = cipher_init(&state->send_context, none,
293 (const u_char *)"", 0, NULL, 0, CIPHER_ENCRYPT)) != 0 ||
294 (r = cipher_init(&state->receive_context, none,
295 (const u_char *)"", 0, NULL, 0, CIPHER_DECRYPT)) != 0) {
296 error_fr(r, "cipher_init failed");
297 free(ssh); /* XXX need ssh_free_session_state? */
298 return NULL;
299 }
300 state->newkeys[MODE_IN] = state->newkeys[MODE_OUT] = NULL;
301 /*
302 * Cache the IP address of the remote connection for use in error
303 * messages that might be generated after the connection has closed.
304 */
305 (void)ssh_remote_ipaddr(ssh);
306 return ssh;
307 }
308
309 void
ssh_packet_set_timeout(struct ssh * ssh,int timeout,int count)310 ssh_packet_set_timeout(struct ssh *ssh, int timeout, int count)
311 {
312 struct session_state *state = ssh->state;
313
314 if (timeout <= 0 || count <= 0) {
315 state->packet_timeout_ms = -1;
316 return;
317 }
318 if ((INT_MAX / 1000) / count < timeout)
319 state->packet_timeout_ms = INT_MAX;
320 else
321 state->packet_timeout_ms = timeout * count * 1000;
322 }
323
324 void
ssh_packet_set_mux(struct ssh * ssh)325 ssh_packet_set_mux(struct ssh *ssh)
326 {
327 ssh->state->mux = 1;
328 ssh->state->rekeying = 0;
329 kex_free(ssh->kex);
330 ssh->kex = NULL;
331 }
332
333 int
ssh_packet_get_mux(struct ssh * ssh)334 ssh_packet_get_mux(struct ssh *ssh)
335 {
336 return ssh->state->mux;
337 }
338
339 int
ssh_packet_set_log_preamble(struct ssh * ssh,const char * fmt,...)340 ssh_packet_set_log_preamble(struct ssh *ssh, const char *fmt, ...)
341 {
342 va_list args;
343 int r;
344
345 free(ssh->log_preamble);
346 if (fmt == NULL)
347 ssh->log_preamble = NULL;
348 else {
349 va_start(args, fmt);
350 r = vasprintf(&ssh->log_preamble, fmt, args);
351 va_end(args);
352 if (r < 0 || ssh->log_preamble == NULL)
353 return SSH_ERR_ALLOC_FAIL;
354 }
355 return 0;
356 }
357
358 int
ssh_packet_stop_discard(struct ssh * ssh)359 ssh_packet_stop_discard(struct ssh *ssh)
360 {
361 struct session_state *state = ssh->state;
362 int r;
363
364 if (state->packet_discard_mac) {
365 char buf[1024];
366 size_t dlen = PACKET_MAX_SIZE;
367
368 if (dlen > state->packet_discard_mac_already)
369 dlen -= state->packet_discard_mac_already;
370 memset(buf, 'a', sizeof(buf));
371 while (sshbuf_len(state->incoming_packet) < dlen)
372 if ((r = sshbuf_put(state->incoming_packet, buf,
373 sizeof(buf))) != 0)
374 return r;
375 (void) mac_compute(state->packet_discard_mac,
376 state->p_read.seqnr,
377 sshbuf_ptr(state->incoming_packet), dlen,
378 NULL, 0);
379 }
380 logit("Finished discarding for %.200s port %d",
381 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
382 return SSH_ERR_MAC_INVALID;
383 }
384
385 static int
ssh_packet_start_discard(struct ssh * ssh,struct sshenc * enc,struct sshmac * mac,size_t mac_already,u_int discard)386 ssh_packet_start_discard(struct ssh *ssh, struct sshenc *enc,
387 struct sshmac *mac, size_t mac_already, u_int discard)
388 {
389 struct session_state *state = ssh->state;
390 int r;
391
392 if (enc == NULL || !cipher_is_cbc(enc->cipher) || (mac && mac->etm)) {
393 if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0)
394 return r;
395 return SSH_ERR_MAC_INVALID;
396 }
397 /*
398 * Record number of bytes over which the mac has already
399 * been computed in order to minimize timing attacks.
400 */
401 if (mac && mac->enabled) {
402 state->packet_discard_mac = mac;
403 state->packet_discard_mac_already = mac_already;
404 }
405 if (sshbuf_len(state->input) >= discard)
406 return ssh_packet_stop_discard(ssh);
407 state->packet_discard = discard - sshbuf_len(state->input);
408 return 0;
409 }
410
411 /* Returns 1 if remote host is connected via socket, 0 if not. */
412
413 int
ssh_packet_connection_is_on_socket(struct ssh * ssh)414 ssh_packet_connection_is_on_socket(struct ssh *ssh)
415 {
416 struct session_state *state;
417 struct sockaddr_storage from, to;
418 socklen_t fromlen, tolen;
419
420 if (ssh == NULL || ssh->state == NULL)
421 return 0;
422
423 state = ssh->state;
424 if (state->connection_in == -1 || state->connection_out == -1)
425 return 0;
426 /* filedescriptors in and out are the same, so it's a socket */
427 if (state->connection_in == state->connection_out)
428 return 1;
429 fromlen = sizeof(from);
430 memset(&from, 0, sizeof(from));
431 if (getpeername(state->connection_in, (struct sockaddr *)&from,
432 &fromlen) == -1)
433 return 0;
434 tolen = sizeof(to);
435 memset(&to, 0, sizeof(to));
436 if (getpeername(state->connection_out, (struct sockaddr *)&to,
437 &tolen) == -1)
438 return 0;
439 if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0)
440 return 0;
441 if (from.ss_family != AF_INET && from.ss_family != AF_INET6)
442 return 0;
443 return 1;
444 }
445
446 void
ssh_packet_get_bytes(struct ssh * ssh,u_int64_t * ibytes,u_int64_t * obytes)447 ssh_packet_get_bytes(struct ssh *ssh, u_int64_t *ibytes, u_int64_t *obytes)
448 {
449 if (ibytes)
450 *ibytes = ssh->state->p_read.bytes;
451 if (obytes)
452 *obytes = ssh->state->p_send.bytes;
453 }
454
455 int
ssh_packet_connection_af(struct ssh * ssh)456 ssh_packet_connection_af(struct ssh *ssh)
457 {
458 return get_sock_af(ssh->state->connection_out);
459 }
460
461 /* Sets the connection into non-blocking mode. */
462
463 void
ssh_packet_set_nonblocking(struct ssh * ssh)464 ssh_packet_set_nonblocking(struct ssh *ssh)
465 {
466 /* Set the socket into non-blocking mode. */
467 set_nonblock(ssh->state->connection_in);
468
469 if (ssh->state->connection_out != ssh->state->connection_in)
470 set_nonblock(ssh->state->connection_out);
471 }
472
473 /* Returns the socket used for reading. */
474
475 int
ssh_packet_get_connection_in(struct ssh * ssh)476 ssh_packet_get_connection_in(struct ssh *ssh)
477 {
478 return ssh->state->connection_in;
479 }
480
481 /* Returns the descriptor used for writing. */
482
483 int
ssh_packet_get_connection_out(struct ssh * ssh)484 ssh_packet_get_connection_out(struct ssh *ssh)
485 {
486 return ssh->state->connection_out;
487 }
488
489 /*
490 * Returns the IP-address of the remote host as a string. The returned
491 * string must not be freed.
492 */
493
494 const char *
ssh_remote_ipaddr(struct ssh * ssh)495 ssh_remote_ipaddr(struct ssh *ssh)
496 {
497 int sock;
498
499 /* Check whether we have cached the ipaddr. */
500 if (ssh->remote_ipaddr == NULL) {
501 if (ssh_packet_connection_is_on_socket(ssh)) {
502 sock = ssh->state->connection_in;
503 ssh->remote_ipaddr = get_peer_ipaddr(sock);
504 ssh->remote_port = get_peer_port(sock);
505 ssh->local_ipaddr = get_local_ipaddr(sock);
506 ssh->local_port = get_local_port(sock);
507 } else {
508 ssh->remote_ipaddr = xstrdup("UNKNOWN");
509 ssh->remote_port = 65535;
510 ssh->local_ipaddr = xstrdup("UNKNOWN");
511 ssh->local_port = 65535;
512 }
513 }
514 return ssh->remote_ipaddr;
515 }
516
517 /* Returns the port number of the remote host. */
518
519 int
ssh_remote_port(struct ssh * ssh)520 ssh_remote_port(struct ssh *ssh)
521 {
522 (void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */
523 return ssh->remote_port;
524 }
525
526 /*
527 * Returns the IP-address of the local host as a string. The returned
528 * string must not be freed.
529 */
530
531 const char *
ssh_local_ipaddr(struct ssh * ssh)532 ssh_local_ipaddr(struct ssh *ssh)
533 {
534 (void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */
535 return ssh->local_ipaddr;
536 }
537
538 /* Returns the port number of the local host. */
539
540 int
ssh_local_port(struct ssh * ssh)541 ssh_local_port(struct ssh *ssh)
542 {
543 (void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */
544 return ssh->local_port;
545 }
546
547 /* Returns the routing domain of the input socket, or NULL if unavailable */
548 const char *
ssh_packet_rdomain_in(struct ssh * ssh)549 ssh_packet_rdomain_in(struct ssh *ssh)
550 {
551 if (ssh->rdomain_in != NULL)
552 return ssh->rdomain_in;
553 if (!ssh_packet_connection_is_on_socket(ssh))
554 return NULL;
555 ssh->rdomain_in = get_rdomain(ssh->state->connection_in);
556 return ssh->rdomain_in;
557 }
558
559 /* Closes the connection and clears and frees internal data structures. */
560
561 static void
ssh_packet_close_internal(struct ssh * ssh,int do_close)562 ssh_packet_close_internal(struct ssh *ssh, int do_close)
563 {
564 struct session_state *state = ssh->state;
565 u_int mode;
566
567 if (!state->initialized)
568 return;
569 state->initialized = 0;
570 if (do_close) {
571 if (state->connection_in == state->connection_out) {
572 close(state->connection_out);
573 } else {
574 close(state->connection_in);
575 close(state->connection_out);
576 }
577 }
578 sshbuf_free(state->input);
579 sshbuf_free(state->output);
580 sshbuf_free(state->outgoing_packet);
581 sshbuf_free(state->incoming_packet);
582 for (mode = 0; mode < MODE_MAX; mode++) {
583 kex_free_newkeys(state->newkeys[mode]); /* current keys */
584 state->newkeys[mode] = NULL;
585 ssh_clear_newkeys(ssh, mode); /* next keys */
586 }
587 #ifdef WITH_ZLIB
588 /* compression state is in shared mem, so we can only release it once */
589 if (do_close && state->compression_buffer) {
590 sshbuf_free(state->compression_buffer);
591 if (state->compression_out_started) {
592 z_streamp stream = &state->compression_out_stream;
593 debug("compress outgoing: "
594 "raw data %llu, compressed %llu, factor %.2f",
595 (unsigned long long)stream->total_in,
596 (unsigned long long)stream->total_out,
597 stream->total_in == 0 ? 0.0 :
598 (double) stream->total_out / stream->total_in);
599 if (state->compression_out_failures == 0)
600 deflateEnd(stream);
601 }
602 if (state->compression_in_started) {
603 z_streamp stream = &state->compression_in_stream;
604 debug("compress incoming: "
605 "raw data %llu, compressed %llu, factor %.2f",
606 (unsigned long long)stream->total_out,
607 (unsigned long long)stream->total_in,
608 stream->total_out == 0 ? 0.0 :
609 (double) stream->total_in / stream->total_out);
610 if (state->compression_in_failures == 0)
611 inflateEnd(stream);
612 }
613 }
614 #endif /* WITH_ZLIB */
615 cipher_free(state->send_context);
616 cipher_free(state->receive_context);
617 state->send_context = state->receive_context = NULL;
618 if (do_close) {
619 free(ssh->local_ipaddr);
620 ssh->local_ipaddr = NULL;
621 free(ssh->remote_ipaddr);
622 ssh->remote_ipaddr = NULL;
623 free(ssh->state);
624 ssh->state = NULL;
625 kex_free(ssh->kex);
626 ssh->kex = NULL;
627 }
628 }
629
630 void
ssh_packet_close(struct ssh * ssh)631 ssh_packet_close(struct ssh *ssh)
632 {
633 ssh_packet_close_internal(ssh, 1);
634 }
635
636 void
ssh_packet_clear_keys(struct ssh * ssh)637 ssh_packet_clear_keys(struct ssh *ssh)
638 {
639 ssh_packet_close_internal(ssh, 0);
640 }
641
642 /* Sets remote side protocol flags. */
643
644 void
ssh_packet_set_protocol_flags(struct ssh * ssh,u_int protocol_flags)645 ssh_packet_set_protocol_flags(struct ssh *ssh, u_int protocol_flags)
646 {
647 ssh->state->remote_protocol_flags = protocol_flags;
648 }
649
650 /* Returns the remote protocol flags set earlier by the above function. */
651
652 u_int
ssh_packet_get_protocol_flags(struct ssh * ssh)653 ssh_packet_get_protocol_flags(struct ssh *ssh)
654 {
655 return ssh->state->remote_protocol_flags;
656 }
657
658 /*
659 * Starts packet compression from the next packet on in both directions.
660 * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip.
661 */
662
663 static int
ssh_packet_init_compression(struct ssh * ssh)664 ssh_packet_init_compression(struct ssh *ssh)
665 {
666 if (!ssh->state->compression_buffer &&
667 ((ssh->state->compression_buffer = sshbuf_new()) == NULL))
668 return SSH_ERR_ALLOC_FAIL;
669 return 0;
670 }
671
672 #ifdef WITH_ZLIB
673 static int
start_compression_out(struct ssh * ssh,int level)674 start_compression_out(struct ssh *ssh, int level)
675 {
676 if (level < 1 || level > 9)
677 return SSH_ERR_INVALID_ARGUMENT;
678 debug("Enabling compression at level %d.", level);
679 if (ssh->state->compression_out_started == 1)
680 deflateEnd(&ssh->state->compression_out_stream);
681 switch (deflateInit(&ssh->state->compression_out_stream, level)) {
682 case Z_OK:
683 ssh->state->compression_out_started = 1;
684 break;
685 case Z_MEM_ERROR:
686 return SSH_ERR_ALLOC_FAIL;
687 default:
688 return SSH_ERR_INTERNAL_ERROR;
689 }
690 return 0;
691 }
692
693 static int
start_compression_in(struct ssh * ssh)694 start_compression_in(struct ssh *ssh)
695 {
696 if (ssh->state->compression_in_started == 1)
697 inflateEnd(&ssh->state->compression_in_stream);
698 switch (inflateInit(&ssh->state->compression_in_stream)) {
699 case Z_OK:
700 ssh->state->compression_in_started = 1;
701 break;
702 case Z_MEM_ERROR:
703 return SSH_ERR_ALLOC_FAIL;
704 default:
705 return SSH_ERR_INTERNAL_ERROR;
706 }
707 return 0;
708 }
709
710 /* XXX remove need for separate compression buffer */
711 static int
compress_buffer(struct ssh * ssh,struct sshbuf * in,struct sshbuf * out)712 compress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out)
713 {
714 u_char buf[4096];
715 int r, status;
716
717 if (ssh->state->compression_out_started != 1)
718 return SSH_ERR_INTERNAL_ERROR;
719
720 /* This case is not handled below. */
721 if (sshbuf_len(in) == 0)
722 return 0;
723
724 /* Input is the contents of the input buffer. */
725 if ((ssh->state->compression_out_stream.next_in =
726 sshbuf_mutable_ptr(in)) == NULL)
727 return SSH_ERR_INTERNAL_ERROR;
728 ssh->state->compression_out_stream.avail_in = sshbuf_len(in);
729
730 /* Loop compressing until deflate() returns with avail_out != 0. */
731 do {
732 /* Set up fixed-size output buffer. */
733 ssh->state->compression_out_stream.next_out = buf;
734 ssh->state->compression_out_stream.avail_out = sizeof(buf);
735
736 /* Compress as much data into the buffer as possible. */
737 status = deflate(&ssh->state->compression_out_stream,
738 Z_PARTIAL_FLUSH);
739 switch (status) {
740 case Z_MEM_ERROR:
741 return SSH_ERR_ALLOC_FAIL;
742 case Z_OK:
743 /* Append compressed data to output_buffer. */
744 if ((r = sshbuf_put(out, buf, sizeof(buf) -
745 ssh->state->compression_out_stream.avail_out)) != 0)
746 return r;
747 break;
748 case Z_STREAM_ERROR:
749 default:
750 ssh->state->compression_out_failures++;
751 return SSH_ERR_INVALID_FORMAT;
752 }
753 } while (ssh->state->compression_out_stream.avail_out == 0);
754 return 0;
755 }
756
757 static int
uncompress_buffer(struct ssh * ssh,struct sshbuf * in,struct sshbuf * out)758 uncompress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out)
759 {
760 u_char buf[4096];
761 int r, status;
762
763 if (ssh->state->compression_in_started != 1)
764 return SSH_ERR_INTERNAL_ERROR;
765
766 if ((ssh->state->compression_in_stream.next_in =
767 sshbuf_mutable_ptr(in)) == NULL)
768 return SSH_ERR_INTERNAL_ERROR;
769 ssh->state->compression_in_stream.avail_in = sshbuf_len(in);
770
771 for (;;) {
772 /* Set up fixed-size output buffer. */
773 ssh->state->compression_in_stream.next_out = buf;
774 ssh->state->compression_in_stream.avail_out = sizeof(buf);
775
776 status = inflate(&ssh->state->compression_in_stream,
777 Z_SYNC_FLUSH);
778 switch (status) {
779 case Z_OK:
780 if ((r = sshbuf_put(out, buf, sizeof(buf) -
781 ssh->state->compression_in_stream.avail_out)) != 0)
782 return r;
783 break;
784 case Z_BUF_ERROR:
785 /*
786 * Comments in zlib.h say that we should keep calling
787 * inflate() until we get an error. This appears to
788 * be the error that we get.
789 */
790 return 0;
791 case Z_DATA_ERROR:
792 return SSH_ERR_INVALID_FORMAT;
793 case Z_MEM_ERROR:
794 return SSH_ERR_ALLOC_FAIL;
795 case Z_STREAM_ERROR:
796 default:
797 ssh->state->compression_in_failures++;
798 return SSH_ERR_INTERNAL_ERROR;
799 }
800 }
801 /* NOTREACHED */
802 }
803
804 #else /* WITH_ZLIB */
805
806 static int
start_compression_out(struct ssh * ssh,int level)807 start_compression_out(struct ssh *ssh, int level)
808 {
809 return SSH_ERR_INTERNAL_ERROR;
810 }
811
812 static int
start_compression_in(struct ssh * ssh)813 start_compression_in(struct ssh *ssh)
814 {
815 return SSH_ERR_INTERNAL_ERROR;
816 }
817
818 static int
compress_buffer(struct ssh * ssh,struct sshbuf * in,struct sshbuf * out)819 compress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out)
820 {
821 return SSH_ERR_INTERNAL_ERROR;
822 }
823
824 static int
uncompress_buffer(struct ssh * ssh,struct sshbuf * in,struct sshbuf * out)825 uncompress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out)
826 {
827 return SSH_ERR_INTERNAL_ERROR;
828 }
829 #endif /* WITH_ZLIB */
830
831 void
ssh_clear_newkeys(struct ssh * ssh,int mode)832 ssh_clear_newkeys(struct ssh *ssh, int mode)
833 {
834 if (ssh->kex && ssh->kex->newkeys[mode]) {
835 kex_free_newkeys(ssh->kex->newkeys[mode]);
836 ssh->kex->newkeys[mode] = NULL;
837 }
838 }
839
840 int
ssh_set_newkeys(struct ssh * ssh,int mode)841 ssh_set_newkeys(struct ssh *ssh, int mode)
842 {
843 struct session_state *state = ssh->state;
844 struct sshenc *enc;
845 struct sshmac *mac;
846 struct sshcomp *comp;
847 struct sshcipher_ctx **ccp;
848 struct packet_state *ps;
849 u_int64_t *max_blocks;
850 const char *wmsg;
851 int r, crypt_type;
852 const char *dir = mode == MODE_OUT ? "out" : "in";
853
854 debug2_f("mode %d", mode);
855
856 if (mode == MODE_OUT) {
857 ccp = &state->send_context;
858 crypt_type = CIPHER_ENCRYPT;
859 ps = &state->p_send;
860 max_blocks = &state->max_blocks_out;
861 } else {
862 ccp = &state->receive_context;
863 crypt_type = CIPHER_DECRYPT;
864 ps = &state->p_read;
865 max_blocks = &state->max_blocks_in;
866 }
867 if (state->newkeys[mode] != NULL) {
868 debug_f("rekeying %s, input %llu bytes %llu blocks, "
869 "output %llu bytes %llu blocks", dir,
870 (unsigned long long)state->p_read.bytes,
871 (unsigned long long)state->p_read.blocks,
872 (unsigned long long)state->p_send.bytes,
873 (unsigned long long)state->p_send.blocks);
874 kex_free_newkeys(state->newkeys[mode]);
875 state->newkeys[mode] = NULL;
876 }
877 /* note that both bytes and the seqnr are not reset */
878 ps->packets = ps->blocks = 0;
879 /* move newkeys from kex to state */
880 if ((state->newkeys[mode] = ssh->kex->newkeys[mode]) == NULL)
881 return SSH_ERR_INTERNAL_ERROR;
882 ssh->kex->newkeys[mode] = NULL;
883 enc = &state->newkeys[mode]->enc;
884 mac = &state->newkeys[mode]->mac;
885 comp = &state->newkeys[mode]->comp;
886 if (cipher_authlen(enc->cipher) == 0) {
887 if ((r = mac_init(mac)) != 0)
888 return r;
889 }
890 mac->enabled = 1;
891 DBG(debug_f("cipher_init: %s", dir));
892 cipher_free(*ccp);
893 *ccp = NULL;
894 if ((r = cipher_init(ccp, enc->cipher, enc->key, enc->key_len,
895 enc->iv, enc->iv_len, crypt_type)) != 0)
896 return r;
897 if (!state->cipher_warning_done &&
898 (wmsg = cipher_warning_message(*ccp)) != NULL) {
899 error("Warning: %s", wmsg);
900 state->cipher_warning_done = 1;
901 }
902 /* Deleting the keys does not gain extra security */
903 /* explicit_bzero(enc->iv, enc->block_size);
904 explicit_bzero(enc->key, enc->key_len);
905 explicit_bzero(mac->key, mac->key_len); */
906 if ((comp->type == COMP_ZLIB ||
907 (comp->type == COMP_DELAYED &&
908 state->after_authentication)) && comp->enabled == 0) {
909 if ((r = ssh_packet_init_compression(ssh)) < 0)
910 return r;
911 if (mode == MODE_OUT) {
912 if ((r = start_compression_out(ssh, 6)) != 0)
913 return r;
914 } else {
915 if ((r = start_compression_in(ssh)) != 0)
916 return r;
917 }
918 comp->enabled = 1;
919 }
920 /*
921 * The 2^(blocksize*2) limit is too expensive for 3DES,
922 * so enforce a 1GB limit for small blocksizes.
923 * See RFC4344 section 3.2.
924 */
925 if (enc->block_size >= 16)
926 *max_blocks = (u_int64_t)1 << (enc->block_size*2);
927 else
928 *max_blocks = ((u_int64_t)1 << 30) / enc->block_size;
929 if (state->rekey_limit)
930 *max_blocks = MINIMUM(*max_blocks,
931 state->rekey_limit / enc->block_size);
932 debug("rekey %s after %llu blocks", dir,
933 (unsigned long long)*max_blocks);
934 return 0;
935 }
936
937 #define MAX_PACKETS (1U<<31)
938 static int
ssh_packet_need_rekeying(struct ssh * ssh,u_int outbound_packet_len)939 ssh_packet_need_rekeying(struct ssh *ssh, u_int outbound_packet_len)
940 {
941 struct session_state *state = ssh->state;
942 u_int32_t out_blocks;
943
944 /* XXX client can't cope with rekeying pre-auth */
945 if (!state->after_authentication)
946 return 0;
947
948 /* Haven't keyed yet or KEX in progress. */
949 if (ssh_packet_is_rekeying(ssh))
950 return 0;
951
952 /* Peer can't rekey */
953 if (ssh->compat & SSH_BUG_NOREKEY)
954 return 0;
955
956 /*
957 * Permit one packet in or out per rekey - this allows us to
958 * make progress when rekey limits are very small.
959 */
960 if (state->p_send.packets == 0 && state->p_read.packets == 0)
961 return 0;
962
963 /* Time-based rekeying */
964 if (state->rekey_interval != 0 &&
965 (int64_t)state->rekey_time + state->rekey_interval <= monotime())
966 return 1;
967
968 /*
969 * Always rekey when MAX_PACKETS sent in either direction
970 * As per RFC4344 section 3.1 we do this after 2^31 packets.
971 */
972 if (state->p_send.packets > MAX_PACKETS ||
973 state->p_read.packets > MAX_PACKETS)
974 return 1;
975
976 /* Rekey after (cipher-specific) maximum blocks */
977 out_blocks = ROUNDUP(outbound_packet_len,
978 state->newkeys[MODE_OUT]->enc.block_size);
979 return (state->max_blocks_out &&
980 (state->p_send.blocks + out_blocks > state->max_blocks_out)) ||
981 (state->max_blocks_in &&
982 (state->p_read.blocks > state->max_blocks_in));
983 }
984
985 int
ssh_packet_check_rekey(struct ssh * ssh)986 ssh_packet_check_rekey(struct ssh *ssh)
987 {
988 if (!ssh_packet_need_rekeying(ssh, 0))
989 return 0;
990 debug3_f("rekex triggered");
991 return kex_start_rekex(ssh);
992 }
993
994 /*
995 * Delayed compression for SSH2 is enabled after authentication:
996 * This happens on the server side after a SSH2_MSG_USERAUTH_SUCCESS is sent,
997 * and on the client side after a SSH2_MSG_USERAUTH_SUCCESS is received.
998 */
999 static int
ssh_packet_enable_delayed_compress(struct ssh * ssh)1000 ssh_packet_enable_delayed_compress(struct ssh *ssh)
1001 {
1002 struct session_state *state = ssh->state;
1003 struct sshcomp *comp = NULL;
1004 int r, mode;
1005
1006 /*
1007 * Remember that we are past the authentication step, so rekeying
1008 * with COMP_DELAYED will turn on compression immediately.
1009 */
1010 state->after_authentication = 1;
1011 for (mode = 0; mode < MODE_MAX; mode++) {
1012 /* protocol error: USERAUTH_SUCCESS received before NEWKEYS */
1013 if (state->newkeys[mode] == NULL)
1014 continue;
1015 comp = &state->newkeys[mode]->comp;
1016 if (comp && !comp->enabled && comp->type == COMP_DELAYED) {
1017 if ((r = ssh_packet_init_compression(ssh)) != 0)
1018 return r;
1019 if (mode == MODE_OUT) {
1020 if ((r = start_compression_out(ssh, 6)) != 0)
1021 return r;
1022 } else {
1023 if ((r = start_compression_in(ssh)) != 0)
1024 return r;
1025 }
1026 comp->enabled = 1;
1027 }
1028 }
1029 return 0;
1030 }
1031
1032 /* Used to mute debug logging for noisy packet types */
1033 int
ssh_packet_log_type(u_char type)1034 ssh_packet_log_type(u_char type)
1035 {
1036 switch (type) {
1037 case SSH2_MSG_PING:
1038 case SSH2_MSG_PONG:
1039 case SSH2_MSG_CHANNEL_DATA:
1040 case SSH2_MSG_CHANNEL_EXTENDED_DATA:
1041 case SSH2_MSG_CHANNEL_WINDOW_ADJUST:
1042 return 0;
1043 default:
1044 return 1;
1045 }
1046 }
1047
1048 /*
1049 * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue)
1050 */
1051 int
ssh_packet_send2_wrapped(struct ssh * ssh)1052 ssh_packet_send2_wrapped(struct ssh *ssh)
1053 {
1054 struct session_state *state = ssh->state;
1055 u_char type, *cp, macbuf[SSH_DIGEST_MAX_LENGTH];
1056 u_char tmp, padlen, pad = 0;
1057 u_int authlen = 0, aadlen = 0;
1058 u_int len;
1059 struct sshenc *enc = NULL;
1060 struct sshmac *mac = NULL;
1061 struct sshcomp *comp = NULL;
1062 int r, block_size;
1063
1064 if (state->newkeys[MODE_OUT] != NULL) {
1065 enc = &state->newkeys[MODE_OUT]->enc;
1066 mac = &state->newkeys[MODE_OUT]->mac;
1067 comp = &state->newkeys[MODE_OUT]->comp;
1068 /* disable mac for authenticated encryption */
1069 if ((authlen = cipher_authlen(enc->cipher)) != 0)
1070 mac = NULL;
1071 }
1072 block_size = enc ? enc->block_size : 8;
1073 aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0;
1074
1075 type = (sshbuf_ptr(state->outgoing_packet))[5];
1076 if (ssh_packet_log_type(type))
1077 debug3("send packet: type %u", type);
1078 #ifdef PACKET_DEBUG
1079 fprintf(stderr, "plain: ");
1080 sshbuf_dump(state->outgoing_packet, stderr);
1081 #endif
1082
1083 if (comp && comp->enabled) {
1084 len = sshbuf_len(state->outgoing_packet);
1085 /* skip header, compress only payload */
1086 if ((r = sshbuf_consume(state->outgoing_packet, 5)) != 0)
1087 goto out;
1088 sshbuf_reset(state->compression_buffer);
1089 if ((r = compress_buffer(ssh, state->outgoing_packet,
1090 state->compression_buffer)) != 0)
1091 goto out;
1092 sshbuf_reset(state->outgoing_packet);
1093 if ((r = sshbuf_put(state->outgoing_packet,
1094 "\0\0\0\0\0", 5)) != 0 ||
1095 (r = sshbuf_putb(state->outgoing_packet,
1096 state->compression_buffer)) != 0)
1097 goto out;
1098 DBG(debug("compression: raw %d compressed %zd", len,
1099 sshbuf_len(state->outgoing_packet)));
1100 }
1101
1102 /* sizeof (packet_len + pad_len + payload) */
1103 len = sshbuf_len(state->outgoing_packet);
1104
1105 /*
1106 * calc size of padding, alloc space, get random data,
1107 * minimum padding is 4 bytes
1108 */
1109 len -= aadlen; /* packet length is not encrypted for EtM modes */
1110 padlen = block_size - (len % block_size);
1111 if (padlen < 4)
1112 padlen += block_size;
1113 if (state->extra_pad) {
1114 tmp = state->extra_pad;
1115 state->extra_pad =
1116 ROUNDUP(state->extra_pad, block_size);
1117 /* check if roundup overflowed */
1118 if (state->extra_pad < tmp)
1119 return SSH_ERR_INVALID_ARGUMENT;
1120 tmp = (len + padlen) % state->extra_pad;
1121 /* Check whether pad calculation below will underflow */
1122 if (tmp > state->extra_pad)
1123 return SSH_ERR_INVALID_ARGUMENT;
1124 pad = state->extra_pad - tmp;
1125 DBG(debug3_f("adding %d (len %d padlen %d extra_pad %d)",
1126 pad, len, padlen, state->extra_pad));
1127 tmp = padlen;
1128 padlen += pad;
1129 /* Check whether padlen calculation overflowed */
1130 if (padlen < tmp)
1131 return SSH_ERR_INVALID_ARGUMENT; /* overflow */
1132 state->extra_pad = 0;
1133 }
1134 if ((r = sshbuf_reserve(state->outgoing_packet, padlen, &cp)) != 0)
1135 goto out;
1136 if (enc && !cipher_ctx_is_plaintext(state->send_context)) {
1137 /* random padding */
1138 arc4random_buf(cp, padlen);
1139 } else {
1140 /* clear padding */
1141 explicit_bzero(cp, padlen);
1142 }
1143 /* sizeof (packet_len + pad_len + payload + padding) */
1144 len = sshbuf_len(state->outgoing_packet);
1145 cp = sshbuf_mutable_ptr(state->outgoing_packet);
1146 if (cp == NULL) {
1147 r = SSH_ERR_INTERNAL_ERROR;
1148 goto out;
1149 }
1150 /* packet_length includes payload, padding and padding length field */
1151 POKE_U32(cp, len - 4);
1152 cp[4] = padlen;
1153 DBG(debug("send: len %d (includes padlen %d, aadlen %d)",
1154 len, padlen, aadlen));
1155
1156 /* compute MAC over seqnr and packet(length fields, payload, padding) */
1157 if (mac && mac->enabled && !mac->etm) {
1158 if ((r = mac_compute(mac, state->p_send.seqnr,
1159 sshbuf_ptr(state->outgoing_packet), len,
1160 macbuf, sizeof(macbuf))) != 0)
1161 goto out;
1162 DBG(debug("done calc MAC out #%d", state->p_send.seqnr));
1163 }
1164 /* encrypt packet and append to output buffer. */
1165 if ((r = sshbuf_reserve(state->output,
1166 sshbuf_len(state->outgoing_packet) + authlen, &cp)) != 0)
1167 goto out;
1168 if ((r = cipher_crypt(state->send_context, state->p_send.seqnr, cp,
1169 sshbuf_ptr(state->outgoing_packet),
1170 len - aadlen, aadlen, authlen)) != 0)
1171 goto out;
1172 /* append unencrypted MAC */
1173 if (mac && mac->enabled) {
1174 if (mac->etm) {
1175 /* EtM: compute mac over aadlen + cipher text */
1176 if ((r = mac_compute(mac, state->p_send.seqnr,
1177 cp, len, macbuf, sizeof(macbuf))) != 0)
1178 goto out;
1179 DBG(debug("done calc MAC(EtM) out #%d",
1180 state->p_send.seqnr));
1181 }
1182 if ((r = sshbuf_put(state->output, macbuf, mac->mac_len)) != 0)
1183 goto out;
1184 }
1185 #ifdef PACKET_DEBUG
1186 fprintf(stderr, "encrypted: ");
1187 sshbuf_dump(state->output, stderr);
1188 #endif
1189 /* increment sequence number for outgoing packets */
1190 if (++state->p_send.seqnr == 0) {
1191 if ((ssh->kex->flags & KEX_INITIAL) != 0) {
1192 ssh_packet_disconnect(ssh, "outgoing sequence number "
1193 "wrapped during initial key exchange");
1194 }
1195 logit("outgoing seqnr wraps around");
1196 }
1197 if (++state->p_send.packets == 0)
1198 if (!(ssh->compat & SSH_BUG_NOREKEY))
1199 return SSH_ERR_NEED_REKEY;
1200 state->p_send.blocks += len / block_size;
1201 state->p_send.bytes += len;
1202 sshbuf_reset(state->outgoing_packet);
1203
1204 if (type == SSH2_MSG_NEWKEYS && ssh->kex->kex_strict) {
1205 debug_f("resetting send seqnr %u", state->p_send.seqnr);
1206 state->p_send.seqnr = 0;
1207 }
1208
1209 if (type == SSH2_MSG_NEWKEYS)
1210 r = ssh_set_newkeys(ssh, MODE_OUT);
1211 else if (type == SSH2_MSG_USERAUTH_SUCCESS && state->server_side)
1212 r = ssh_packet_enable_delayed_compress(ssh);
1213 else
1214 r = 0;
1215 out:
1216 return r;
1217 }
1218
1219 /* returns non-zero if the specified packet type is usec by KEX */
1220 static int
ssh_packet_type_is_kex(u_char type)1221 ssh_packet_type_is_kex(u_char type)
1222 {
1223 return
1224 type >= SSH2_MSG_TRANSPORT_MIN &&
1225 type <= SSH2_MSG_TRANSPORT_MAX &&
1226 type != SSH2_MSG_SERVICE_REQUEST &&
1227 type != SSH2_MSG_SERVICE_ACCEPT &&
1228 type != SSH2_MSG_EXT_INFO;
1229 }
1230
1231 int
ssh_packet_send2(struct ssh * ssh)1232 ssh_packet_send2(struct ssh *ssh)
1233 {
1234 struct session_state *state = ssh->state;
1235 struct packet *p;
1236 u_char type;
1237 int r, need_rekey;
1238
1239 if (sshbuf_len(state->outgoing_packet) < 6)
1240 return SSH_ERR_INTERNAL_ERROR;
1241 type = sshbuf_ptr(state->outgoing_packet)[5];
1242 need_rekey = !ssh_packet_type_is_kex(type) &&
1243 ssh_packet_need_rekeying(ssh, sshbuf_len(state->outgoing_packet));
1244
1245 /*
1246 * During rekeying we can only send key exchange messages.
1247 * Queue everything else.
1248 */
1249 if ((need_rekey || state->rekeying) && !ssh_packet_type_is_kex(type)) {
1250 if (need_rekey)
1251 debug3_f("rekex triggered");
1252 debug("enqueue packet: %u", type);
1253 p = calloc(1, sizeof(*p));
1254 if (p == NULL)
1255 return SSH_ERR_ALLOC_FAIL;
1256 p->type = type;
1257 p->payload = state->outgoing_packet;
1258 TAILQ_INSERT_TAIL(&state->outgoing, p, next);
1259 state->outgoing_packet = sshbuf_new();
1260 if (state->outgoing_packet == NULL)
1261 return SSH_ERR_ALLOC_FAIL;
1262 if (need_rekey) {
1263 /*
1264 * This packet triggered a rekey, so send the
1265 * KEXINIT now.
1266 * NB. reenters this function via kex_start_rekex().
1267 */
1268 return kex_start_rekex(ssh);
1269 }
1270 return 0;
1271 }
1272
1273 /* rekeying starts with sending KEXINIT */
1274 if (type == SSH2_MSG_KEXINIT)
1275 state->rekeying = 1;
1276
1277 if ((r = ssh_packet_send2_wrapped(ssh)) != 0)
1278 return r;
1279
1280 /* after a NEWKEYS message we can send the complete queue */
1281 if (type == SSH2_MSG_NEWKEYS) {
1282 state->rekeying = 0;
1283 state->rekey_time = monotime();
1284 while ((p = TAILQ_FIRST(&state->outgoing))) {
1285 type = p->type;
1286 /*
1287 * If this packet triggers a rekex, then skip the
1288 * remaining packets in the queue for now.
1289 * NB. re-enters this function via kex_start_rekex.
1290 */
1291 if (ssh_packet_need_rekeying(ssh,
1292 sshbuf_len(p->payload))) {
1293 debug3_f("queued packet triggered rekex");
1294 return kex_start_rekex(ssh);
1295 }
1296 debug("dequeue packet: %u", type);
1297 sshbuf_free(state->outgoing_packet);
1298 state->outgoing_packet = p->payload;
1299 TAILQ_REMOVE(&state->outgoing, p, next);
1300 memset(p, 0, sizeof(*p));
1301 free(p);
1302 if ((r = ssh_packet_send2_wrapped(ssh)) != 0)
1303 return r;
1304 }
1305 }
1306 return 0;
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 if ((r = ssh_packet_read_poll_seqnr(ssh, typep, seqnr_p)) != 0)
1338 break;
1339 /* If we got a packet, return it. */
1340 if (*typep != SSH_MSG_NONE)
1341 break;
1342 /*
1343 * Otherwise, wait for some data to arrive, add it to the
1344 * buffer, and try again.
1345 */
1346 pfd.fd = state->connection_in;
1347 pfd.events = POLLIN;
1348
1349 if (state->packet_timeout_ms > 0) {
1350 ms_remain = state->packet_timeout_ms;
1351 timespecp = ×pec;
1352 }
1353 /* Wait for some data to arrive. */
1354 for (;;) {
1355 if (state->packet_timeout_ms > 0) {
1356 ms_to_timespec(×pec, ms_remain);
1357 monotime_tv(&start);
1358 }
1359 if ((r = ppoll(&pfd, 1, timespecp, NULL)) >= 0)
1360 break;
1361 if (errno != EAGAIN && errno != EINTR) {
1362 r = SSH_ERR_SYSTEM_ERROR;
1363 goto out;
1364 }
1365 if (state->packet_timeout_ms <= 0)
1366 continue;
1367 ms_subtract_diff(&start, &ms_remain);
1368 if (ms_remain <= 0) {
1369 r = 0;
1370 break;
1371 }
1372 }
1373 if (r == 0) {
1374 r = SSH_ERR_CONN_TIMEOUT;
1375 goto out;
1376 }
1377 /* Read data from the socket. */
1378 len = read(state->connection_in, buf, sizeof(buf));
1379 if (len == 0) {
1380 r = SSH_ERR_CONN_CLOSED;
1381 goto out;
1382 }
1383 if (len == -1) {
1384 r = SSH_ERR_SYSTEM_ERROR;
1385 goto out;
1386 }
1387
1388 /* Append it to the buffer. */
1389 if ((r = ssh_packet_process_incoming(ssh, buf, len)) != 0)
1390 goto out;
1391 }
1392 out:
1393 return r;
1394 }
1395
1396 int
ssh_packet_read(struct ssh * ssh)1397 ssh_packet_read(struct ssh *ssh)
1398 {
1399 u_char type;
1400 int r;
1401
1402 if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0)
1403 fatal_fr(r, "read");
1404 return type;
1405 }
1406
1407 static int
ssh_packet_read_poll2_mux(struct ssh * ssh,u_char * typep,u_int32_t * seqnr_p)1408 ssh_packet_read_poll2_mux(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
1409 {
1410 struct session_state *state = ssh->state;
1411 const u_char *cp;
1412 size_t need;
1413 int r;
1414
1415 if (ssh->kex)
1416 return SSH_ERR_INTERNAL_ERROR;
1417 *typep = SSH_MSG_NONE;
1418 cp = sshbuf_ptr(state->input);
1419 if (state->packlen == 0) {
1420 if (sshbuf_len(state->input) < 4 + 1)
1421 return 0; /* packet is incomplete */
1422 state->packlen = PEEK_U32(cp);
1423 if (state->packlen < 4 + 1 ||
1424 state->packlen > PACKET_MAX_SIZE)
1425 return SSH_ERR_MESSAGE_INCOMPLETE;
1426 }
1427 need = state->packlen + 4;
1428 if (sshbuf_len(state->input) < need)
1429 return 0; /* packet is incomplete */
1430 sshbuf_reset(state->incoming_packet);
1431 if ((r = sshbuf_put(state->incoming_packet, cp + 4,
1432 state->packlen)) != 0 ||
1433 (r = sshbuf_consume(state->input, need)) != 0 ||
1434 (r = sshbuf_get_u8(state->incoming_packet, NULL)) != 0 ||
1435 (r = sshbuf_get_u8(state->incoming_packet, typep)) != 0)
1436 return r;
1437 if (ssh_packet_log_type(*typep))
1438 debug3_f("type %u", *typep);
1439 /* sshbuf_dump(state->incoming_packet, stderr); */
1440 /* reset for next packet */
1441 state->packlen = 0;
1442 return r;
1443 }
1444
1445 int
ssh_packet_read_poll2(struct ssh * ssh,u_char * typep,u_int32_t * seqnr_p)1446 ssh_packet_read_poll2(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
1447 {
1448 struct session_state *state = ssh->state;
1449 u_int padlen, need;
1450 u_char *cp;
1451 u_int maclen, aadlen = 0, authlen = 0, block_size;
1452 struct sshenc *enc = NULL;
1453 struct sshmac *mac = NULL;
1454 struct sshcomp *comp = NULL;
1455 int r;
1456
1457 if (state->mux)
1458 return ssh_packet_read_poll2_mux(ssh, typep, seqnr_p);
1459
1460 *typep = SSH_MSG_NONE;
1461
1462 if (state->packet_discard)
1463 return 0;
1464
1465 if (state->newkeys[MODE_IN] != NULL) {
1466 enc = &state->newkeys[MODE_IN]->enc;
1467 mac = &state->newkeys[MODE_IN]->mac;
1468 comp = &state->newkeys[MODE_IN]->comp;
1469 /* disable mac for authenticated encryption */
1470 if ((authlen = cipher_authlen(enc->cipher)) != 0)
1471 mac = NULL;
1472 }
1473 maclen = mac && mac->enabled ? mac->mac_len : 0;
1474 block_size = enc ? enc->block_size : 8;
1475 aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0;
1476
1477 if (aadlen && state->packlen == 0) {
1478 if (cipher_get_length(state->receive_context,
1479 &state->packlen, state->p_read.seqnr,
1480 sshbuf_ptr(state->input), sshbuf_len(state->input)) != 0)
1481 return 0;
1482 if (state->packlen < 1 + 4 ||
1483 state->packlen > PACKET_MAX_SIZE) {
1484 #ifdef PACKET_DEBUG
1485 sshbuf_dump(state->input, stderr);
1486 #endif
1487 logit("Bad packet length %u.", state->packlen);
1488 if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0)
1489 return r;
1490 return SSH_ERR_CONN_CORRUPT;
1491 }
1492 sshbuf_reset(state->incoming_packet);
1493 } else if (state->packlen == 0) {
1494 /*
1495 * check if input size is less than the cipher block size,
1496 * decrypt first block and extract length of incoming packet
1497 */
1498 if (sshbuf_len(state->input) < block_size)
1499 return 0;
1500 sshbuf_reset(state->incoming_packet);
1501 if ((r = sshbuf_reserve(state->incoming_packet, block_size,
1502 &cp)) != 0)
1503 goto out;
1504 if ((r = cipher_crypt(state->receive_context,
1505 state->p_send.seqnr, cp, sshbuf_ptr(state->input),
1506 block_size, 0, 0)) != 0)
1507 goto out;
1508 state->packlen = PEEK_U32(sshbuf_ptr(state->incoming_packet));
1509 if (state->packlen < 1 + 4 ||
1510 state->packlen > PACKET_MAX_SIZE) {
1511 #ifdef PACKET_DEBUG
1512 fprintf(stderr, "input: \n");
1513 sshbuf_dump(state->input, stderr);
1514 fprintf(stderr, "incoming_packet: \n");
1515 sshbuf_dump(state->incoming_packet, stderr);
1516 #endif
1517 logit("Bad packet length %u.", state->packlen);
1518 return ssh_packet_start_discard(ssh, enc, mac, 0,
1519 PACKET_MAX_SIZE);
1520 }
1521 if ((r = sshbuf_consume(state->input, block_size)) != 0)
1522 goto out;
1523 }
1524 DBG(debug("input: packet len %u", state->packlen+4));
1525
1526 if (aadlen) {
1527 /* only the payload is encrypted */
1528 need = state->packlen;
1529 } else {
1530 /*
1531 * the payload size and the payload are encrypted, but we
1532 * have a partial packet of block_size bytes
1533 */
1534 need = 4 + state->packlen - block_size;
1535 }
1536 DBG(debug("partial packet: block %d, need %d, maclen %d, authlen %d,"
1537 " aadlen %d", block_size, need, maclen, authlen, aadlen));
1538 if (need % block_size != 0) {
1539 logit("padding error: need %d block %d mod %d",
1540 need, block_size, need % block_size);
1541 return ssh_packet_start_discard(ssh, enc, mac, 0,
1542 PACKET_MAX_SIZE - block_size);
1543 }
1544 /*
1545 * check if the entire packet has been received and
1546 * decrypt into incoming_packet:
1547 * 'aadlen' bytes are unencrypted, but authenticated.
1548 * 'need' bytes are encrypted, followed by either
1549 * 'authlen' bytes of authentication tag or
1550 * 'maclen' bytes of message authentication code.
1551 */
1552 if (sshbuf_len(state->input) < aadlen + need + authlen + maclen)
1553 return 0; /* packet is incomplete */
1554 #ifdef PACKET_DEBUG
1555 fprintf(stderr, "read_poll enc/full: ");
1556 sshbuf_dump(state->input, stderr);
1557 #endif
1558 /* EtM: check mac over encrypted input */
1559 if (mac && mac->enabled && mac->etm) {
1560 if ((r = mac_check(mac, state->p_read.seqnr,
1561 sshbuf_ptr(state->input), aadlen + need,
1562 sshbuf_ptr(state->input) + aadlen + need + authlen,
1563 maclen)) != 0) {
1564 if (r == SSH_ERR_MAC_INVALID)
1565 logit("Corrupted MAC on input.");
1566 goto out;
1567 }
1568 }
1569 if ((r = sshbuf_reserve(state->incoming_packet, aadlen + need,
1570 &cp)) != 0)
1571 goto out;
1572 if ((r = cipher_crypt(state->receive_context, state->p_read.seqnr, cp,
1573 sshbuf_ptr(state->input), need, aadlen, authlen)) != 0)
1574 goto out;
1575 if ((r = sshbuf_consume(state->input, aadlen + need + authlen)) != 0)
1576 goto out;
1577 if (mac && mac->enabled) {
1578 /* Not EtM: check MAC over cleartext */
1579 if (!mac->etm && (r = mac_check(mac, state->p_read.seqnr,
1580 sshbuf_ptr(state->incoming_packet),
1581 sshbuf_len(state->incoming_packet),
1582 sshbuf_ptr(state->input), maclen)) != 0) {
1583 if (r != SSH_ERR_MAC_INVALID)
1584 goto out;
1585 logit("Corrupted MAC on input.");
1586 if (need + block_size > PACKET_MAX_SIZE)
1587 return SSH_ERR_INTERNAL_ERROR;
1588 return ssh_packet_start_discard(ssh, enc, mac,
1589 sshbuf_len(state->incoming_packet),
1590 PACKET_MAX_SIZE - need - block_size);
1591 }
1592 /* Remove MAC from input buffer */
1593 DBG(debug("MAC #%d ok", state->p_read.seqnr));
1594 if ((r = sshbuf_consume(state->input, mac->mac_len)) != 0)
1595 goto out;
1596 }
1597
1598 if (seqnr_p != NULL)
1599 *seqnr_p = state->p_read.seqnr;
1600 if (++state->p_read.seqnr == 0) {
1601 if ((ssh->kex->flags & KEX_INITIAL) != 0) {
1602 ssh_packet_disconnect(ssh, "incoming sequence number "
1603 "wrapped during initial key exchange");
1604 }
1605 logit("incoming seqnr wraps around");
1606 }
1607 if (++state->p_read.packets == 0)
1608 if (!(ssh->compat & SSH_BUG_NOREKEY))
1609 return SSH_ERR_NEED_REKEY;
1610 state->p_read.blocks += (state->packlen + 4) / block_size;
1611 state->p_read.bytes += state->packlen + 4;
1612
1613 /* get padlen */
1614 padlen = sshbuf_ptr(state->incoming_packet)[4];
1615 DBG(debug("input: padlen %d", padlen));
1616 if (padlen < 4) {
1617 if ((r = sshpkt_disconnect(ssh,
1618 "Corrupted padlen %d on input.", padlen)) != 0 ||
1619 (r = ssh_packet_write_wait(ssh)) != 0)
1620 return r;
1621 return SSH_ERR_CONN_CORRUPT;
1622 }
1623
1624 /* skip packet size + padlen, discard padding */
1625 if ((r = sshbuf_consume(state->incoming_packet, 4 + 1)) != 0 ||
1626 ((r = sshbuf_consume_end(state->incoming_packet, padlen)) != 0))
1627 goto out;
1628
1629 DBG(debug("input: len before de-compress %zd",
1630 sshbuf_len(state->incoming_packet)));
1631 if (comp && comp->enabled) {
1632 sshbuf_reset(state->compression_buffer);
1633 if ((r = uncompress_buffer(ssh, state->incoming_packet,
1634 state->compression_buffer)) != 0)
1635 goto out;
1636 sshbuf_reset(state->incoming_packet);
1637 if ((r = sshbuf_putb(state->incoming_packet,
1638 state->compression_buffer)) != 0)
1639 goto out;
1640 DBG(debug("input: len after de-compress %zd",
1641 sshbuf_len(state->incoming_packet)));
1642 }
1643 /*
1644 * get packet type, implies consume.
1645 * return length of payload (without type field)
1646 */
1647 if ((r = sshbuf_get_u8(state->incoming_packet, typep)) != 0)
1648 goto out;
1649 if (ssh_packet_log_type(*typep))
1650 debug3("receive packet: type %u", *typep);
1651 if (*typep < SSH2_MSG_MIN) {
1652 if ((r = sshpkt_disconnect(ssh,
1653 "Invalid ssh2 packet type: %d", *typep)) != 0 ||
1654 (r = ssh_packet_write_wait(ssh)) != 0)
1655 return r;
1656 return SSH_ERR_PROTOCOL_ERROR;
1657 }
1658 if (state->hook_in != NULL &&
1659 (r = state->hook_in(ssh, state->incoming_packet, typep,
1660 state->hook_in_ctx)) != 0)
1661 return r;
1662 if (*typep == SSH2_MSG_USERAUTH_SUCCESS && !state->server_side)
1663 r = ssh_packet_enable_delayed_compress(ssh);
1664 else
1665 r = 0;
1666 #ifdef PACKET_DEBUG
1667 fprintf(stderr, "read/plain[%d]:\r\n", *typep);
1668 sshbuf_dump(state->incoming_packet, stderr);
1669 #endif
1670 /* reset for next packet */
1671 state->packlen = 0;
1672 if (*typep == SSH2_MSG_NEWKEYS && ssh->kex->kex_strict) {
1673 debug_f("resetting read seqnr %u", state->p_read.seqnr);
1674 state->p_read.seqnr = 0;
1675 }
1676
1677 if ((r = ssh_packet_check_rekey(ssh)) != 0)
1678 return r;
1679 out:
1680 return r;
1681 }
1682
1683 int
ssh_packet_read_poll_seqnr(struct ssh * ssh,u_char * typep,u_int32_t * seqnr_p)1684 ssh_packet_read_poll_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
1685 {
1686 struct session_state *state = ssh->state;
1687 u_int reason, seqnr;
1688 int r;
1689 u_char *msg;
1690 const u_char *d;
1691 size_t len;
1692
1693 for (;;) {
1694 msg = NULL;
1695 r = ssh_packet_read_poll2(ssh, typep, seqnr_p);
1696 if (r != 0)
1697 return r;
1698 if (*typep == 0) {
1699 /* no message ready */
1700 return 0;
1701 }
1702 state->keep_alive_timeouts = 0;
1703 DBG(debug("received packet type %d", *typep));
1704
1705 /* Always process disconnect messages */
1706 if (*typep == SSH2_MSG_DISCONNECT) {
1707 if ((r = sshpkt_get_u32(ssh, &reason)) != 0 ||
1708 (r = sshpkt_get_string(ssh, &msg, NULL)) != 0)
1709 return r;
1710 /* Ignore normal client exit notifications */
1711 do_log2(ssh->state->server_side &&
1712 reason == SSH2_DISCONNECT_BY_APPLICATION ?
1713 SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_ERROR,
1714 "Received disconnect from %s port %d:"
1715 "%u: %.400s", ssh_remote_ipaddr(ssh),
1716 ssh_remote_port(ssh), reason, msg);
1717 free(msg);
1718 return SSH_ERR_DISCONNECTED;
1719 }
1720
1721 /*
1722 * Do not implicitly handle any messages here during initial
1723 * KEX when in strict mode. They will be need to be allowed
1724 * explicitly by the KEX dispatch table or they will generate
1725 * protocol errors.
1726 */
1727 if (ssh->kex != NULL &&
1728 (ssh->kex->flags & KEX_INITIAL) && ssh->kex->kex_strict)
1729 return 0;
1730 /* Implicitly handle transport-level messages */
1731 switch (*typep) {
1732 case SSH2_MSG_IGNORE:
1733 debug3("Received SSH2_MSG_IGNORE");
1734 break;
1735 case SSH2_MSG_DEBUG:
1736 if ((r = sshpkt_get_u8(ssh, NULL)) != 0 ||
1737 (r = sshpkt_get_string(ssh, &msg, NULL)) != 0 ||
1738 (r = sshpkt_get_string(ssh, NULL, NULL)) != 0) {
1739 free(msg);
1740 return r;
1741 }
1742 debug("Remote: %.900s", msg);
1743 free(msg);
1744 break;
1745 case SSH2_MSG_UNIMPLEMENTED:
1746 if ((r = sshpkt_get_u32(ssh, &seqnr)) != 0)
1747 return r;
1748 debug("Received SSH2_MSG_UNIMPLEMENTED for %u",
1749 seqnr);
1750 break;
1751 case SSH2_MSG_PING:
1752 if ((r = sshpkt_get_string_direct(ssh, &d, &len)) != 0)
1753 return r;
1754 DBG(debug("Received SSH2_MSG_PING len %zu", len));
1755 if ((r = sshpkt_start(ssh, SSH2_MSG_PONG)) != 0 ||
1756 (r = sshpkt_put_string(ssh, d, len)) != 0 ||
1757 (r = sshpkt_send(ssh)) != 0)
1758 return r;
1759 break;
1760 case SSH2_MSG_PONG:
1761 if ((r = sshpkt_get_string_direct(ssh,
1762 NULL, &len)) != 0)
1763 return r;
1764 DBG(debug("Received SSH2_MSG_PONG len %zu", len));
1765 break;
1766 default:
1767 return 0;
1768 }
1769 }
1770 }
1771
1772 /*
1773 * Buffers the supplied input data. This is intended to be used together
1774 * with packet_read_poll().
1775 */
1776 int
ssh_packet_process_incoming(struct ssh * ssh,const char * buf,u_int len)1777 ssh_packet_process_incoming(struct ssh *ssh, const char *buf, u_int len)
1778 {
1779 struct session_state *state = ssh->state;
1780 int r;
1781
1782 if (state->packet_discard) {
1783 state->keep_alive_timeouts = 0; /* ?? */
1784 if (len >= state->packet_discard) {
1785 if ((r = ssh_packet_stop_discard(ssh)) != 0)
1786 return r;
1787 }
1788 state->packet_discard -= len;
1789 return 0;
1790 }
1791 if ((r = sshbuf_put(state->input, buf, len)) != 0)
1792 return r;
1793
1794 return 0;
1795 }
1796
1797 /* Reads and buffers data from the specified fd */
1798 int
ssh_packet_process_read(struct ssh * ssh,int fd)1799 ssh_packet_process_read(struct ssh *ssh, int fd)
1800 {
1801 struct session_state *state = ssh->state;
1802 int r;
1803 size_t rlen;
1804
1805 if ((r = sshbuf_read(fd, state->input, PACKET_MAX_SIZE, &rlen)) != 0)
1806 return r;
1807
1808 if (state->packet_discard) {
1809 if ((r = sshbuf_consume_end(state->input, rlen)) != 0)
1810 return r;
1811 state->keep_alive_timeouts = 0; /* ?? */
1812 if (rlen >= state->packet_discard) {
1813 if ((r = ssh_packet_stop_discard(ssh)) != 0)
1814 return r;
1815 }
1816 state->packet_discard -= rlen;
1817 return 0;
1818 }
1819 return 0;
1820 }
1821
1822 int
ssh_packet_remaining(struct ssh * ssh)1823 ssh_packet_remaining(struct ssh *ssh)
1824 {
1825 return sshbuf_len(ssh->state->incoming_packet);
1826 }
1827
1828 /*
1829 * Sends a diagnostic message from the server to the client. This message
1830 * can be sent at any time (but not while constructing another message). The
1831 * message is printed immediately, but only if the client is being executed
1832 * in verbose mode. These messages are primarily intended to ease debugging
1833 * authentication problems. The length of the formatted message must not
1834 * exceed 1024 bytes. This will automatically call ssh_packet_write_wait.
1835 */
1836 void
ssh_packet_send_debug(struct ssh * ssh,const char * fmt,...)1837 ssh_packet_send_debug(struct ssh *ssh, const char *fmt,...)
1838 {
1839 char buf[1024];
1840 va_list args;
1841 int r;
1842
1843 if ((ssh->compat & SSH_BUG_DEBUG))
1844 return;
1845
1846 va_start(args, fmt);
1847 vsnprintf(buf, sizeof(buf), fmt, args);
1848 va_end(args);
1849
1850 debug3("sending debug message: %s", buf);
1851
1852 if ((r = sshpkt_start(ssh, SSH2_MSG_DEBUG)) != 0 ||
1853 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* always display */
1854 (r = sshpkt_put_cstring(ssh, buf)) != 0 ||
1855 (r = sshpkt_put_cstring(ssh, "")) != 0 ||
1856 (r = sshpkt_send(ssh)) != 0 ||
1857 (r = ssh_packet_write_wait(ssh)) != 0)
1858 fatal_fr(r, "send DEBUG");
1859 }
1860
1861 void
sshpkt_fmt_connection_id(struct ssh * ssh,char * s,size_t l)1862 sshpkt_fmt_connection_id(struct ssh *ssh, char *s, size_t l)
1863 {
1864 snprintf(s, l, "%.200s%s%s port %d",
1865 ssh->log_preamble ? ssh->log_preamble : "",
1866 ssh->log_preamble ? " " : "",
1867 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
1868 }
1869
1870 /*
1871 * Pretty-print connection-terminating errors and exit.
1872 */
1873 static void
sshpkt_vfatal(struct ssh * ssh,int r,const char * fmt,va_list ap)1874 sshpkt_vfatal(struct ssh *ssh, int r, const char *fmt, va_list ap)
1875 {
1876 char *tag = NULL, remote_id[512];
1877 int oerrno = errno;
1878
1879 sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id));
1880
1881 switch (r) {
1882 case SSH_ERR_CONN_CLOSED:
1883 ssh_packet_clear_keys(ssh);
1884 logdie("Connection closed by %s", remote_id);
1885 case SSH_ERR_CONN_TIMEOUT:
1886 ssh_packet_clear_keys(ssh);
1887 logdie("Connection %s %s timed out",
1888 ssh->state->server_side ? "from" : "to", remote_id);
1889 case SSH_ERR_DISCONNECTED:
1890 ssh_packet_clear_keys(ssh);
1891 logdie("Disconnected from %s", remote_id);
1892 case SSH_ERR_SYSTEM_ERROR:
1893 if (errno == ECONNRESET) {
1894 ssh_packet_clear_keys(ssh);
1895 logdie("Connection reset by %s", remote_id);
1896 }
1897 /* FALLTHROUGH */
1898 case SSH_ERR_NO_CIPHER_ALG_MATCH:
1899 case SSH_ERR_NO_MAC_ALG_MATCH:
1900 case SSH_ERR_NO_COMPRESS_ALG_MATCH:
1901 case SSH_ERR_NO_KEX_ALG_MATCH:
1902 case SSH_ERR_NO_HOSTKEY_ALG_MATCH:
1903 if (ssh->kex && ssh->kex->failed_choice) {
1904 ssh_packet_clear_keys(ssh);
1905 errno = oerrno;
1906 logdie("Unable to negotiate with %s: %s. "
1907 "Their offer: %s", remote_id, ssh_err(r),
1908 ssh->kex->failed_choice);
1909 }
1910 /* FALLTHROUGH */
1911 default:
1912 if (vasprintf(&tag, fmt, ap) == -1) {
1913 ssh_packet_clear_keys(ssh);
1914 logdie_f("could not allocate failure message");
1915 }
1916 ssh_packet_clear_keys(ssh);
1917 errno = oerrno;
1918 logdie_r(r, "%s%sConnection %s %s",
1919 tag != NULL ? tag : "", tag != NULL ? ": " : "",
1920 ssh->state->server_side ? "from" : "to", remote_id);
1921 }
1922 }
1923
1924 void
sshpkt_fatal(struct ssh * ssh,int r,const char * fmt,...)1925 sshpkt_fatal(struct ssh *ssh, int r, const char *fmt, ...)
1926 {
1927 va_list ap;
1928
1929 va_start(ap, fmt);
1930 sshpkt_vfatal(ssh, r, fmt, ap);
1931 /* NOTREACHED */
1932 va_end(ap);
1933 logdie_f("should have exited");
1934 }
1935
1936 /*
1937 * Logs the error plus constructs and sends a disconnect packet, closes the
1938 * connection, and exits. This function never returns. The error message
1939 * should not contain a newline. The length of the formatted message must
1940 * not exceed 1024 bytes.
1941 */
1942 void
ssh_packet_disconnect(struct ssh * ssh,const char * fmt,...)1943 ssh_packet_disconnect(struct ssh *ssh, const char *fmt,...)
1944 {
1945 char buf[1024], remote_id[512];
1946 va_list args;
1947 static int disconnecting = 0;
1948 int r;
1949
1950 if (disconnecting) /* Guard against recursive invocations. */
1951 fatal("packet_disconnect called recursively.");
1952 disconnecting = 1;
1953
1954 /*
1955 * Format the message. Note that the caller must make sure the
1956 * message is of limited size.
1957 */
1958 sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id));
1959 va_start(args, fmt);
1960 vsnprintf(buf, sizeof(buf), fmt, args);
1961 va_end(args);
1962
1963 /* Display the error locally */
1964 logit("Disconnecting %s: %.100s", remote_id, buf);
1965
1966 /*
1967 * Send the disconnect message to the other side, and wait
1968 * for it to get sent.
1969 */
1970 if ((r = sshpkt_disconnect(ssh, "%s", buf)) != 0)
1971 sshpkt_fatal(ssh, r, "%s", __func__);
1972
1973 if ((r = ssh_packet_write_wait(ssh)) != 0)
1974 sshpkt_fatal(ssh, r, "%s", __func__);
1975
1976 /* Close the connection. */
1977 ssh_packet_close(ssh);
1978 cleanup_exit(255);
1979 }
1980
1981 /*
1982 * Checks if there is any buffered output, and tries to write some of
1983 * the output.
1984 */
1985 int
ssh_packet_write_poll(struct ssh * ssh)1986 ssh_packet_write_poll(struct ssh *ssh)
1987 {
1988 struct session_state *state = ssh->state;
1989 int len = sshbuf_len(state->output);
1990 int r;
1991
1992 if (len > 0) {
1993 len = write(state->connection_out,
1994 sshbuf_ptr(state->output), len);
1995 if (len == -1) {
1996 if (errno == EINTR || errno == EAGAIN)
1997 return 0;
1998 return SSH_ERR_SYSTEM_ERROR;
1999 }
2000 if (len == 0)
2001 return SSH_ERR_CONN_CLOSED;
2002 if ((r = sshbuf_consume(state->output, len)) != 0)
2003 return r;
2004 }
2005 return 0;
2006 }
2007
2008 /*
2009 * Calls packet_write_poll repeatedly until all pending output data has been
2010 * written.
2011 */
2012 int
ssh_packet_write_wait(struct ssh * ssh)2013 ssh_packet_write_wait(struct ssh *ssh)
2014 {
2015 int ret, r, ms_remain = 0;
2016 struct timeval start;
2017 struct timespec timespec, *timespecp = NULL;
2018 struct session_state *state = ssh->state;
2019 struct pollfd pfd;
2020
2021 if ((r = ssh_packet_write_poll(ssh)) != 0)
2022 return r;
2023 while (ssh_packet_have_data_to_write(ssh)) {
2024 pfd.fd = state->connection_out;
2025 pfd.events = POLLOUT;
2026
2027 if (state->packet_timeout_ms > 0) {
2028 ms_remain = state->packet_timeout_ms;
2029 timespecp = ×pec;
2030 }
2031 for (;;) {
2032 if (state->packet_timeout_ms > 0) {
2033 ms_to_timespec(×pec, ms_remain);
2034 monotime_tv(&start);
2035 }
2036 if ((ret = ppoll(&pfd, 1, timespecp, NULL)) >= 0)
2037 break;
2038 if (errno != EAGAIN && errno != EINTR)
2039 break;
2040 if (state->packet_timeout_ms <= 0)
2041 continue;
2042 ms_subtract_diff(&start, &ms_remain);
2043 if (ms_remain <= 0) {
2044 ret = 0;
2045 break;
2046 }
2047 }
2048 if (ret == 0)
2049 return SSH_ERR_CONN_TIMEOUT;
2050 if ((r = ssh_packet_write_poll(ssh)) != 0)
2051 return r;
2052 }
2053 return 0;
2054 }
2055
2056 /* Returns true if there is buffered data to write to the connection. */
2057
2058 int
ssh_packet_have_data_to_write(struct ssh * ssh)2059 ssh_packet_have_data_to_write(struct ssh *ssh)
2060 {
2061 return sshbuf_len(ssh->state->output) != 0;
2062 }
2063
2064 /* Returns true if there is not too much data to write to the connection. */
2065
2066 int
ssh_packet_not_very_much_data_to_write(struct ssh * ssh)2067 ssh_packet_not_very_much_data_to_write(struct ssh *ssh)
2068 {
2069 if (ssh->state->interactive_mode)
2070 return sshbuf_len(ssh->state->output) < 16384;
2071 else
2072 return sshbuf_len(ssh->state->output) < 128 * 1024;
2073 }
2074
2075 /*
2076 * returns true when there are at most a few keystrokes of data to write
2077 * and the connection is in interactive mode.
2078 */
2079
2080 int
ssh_packet_interactive_data_to_write(struct ssh * ssh)2081 ssh_packet_interactive_data_to_write(struct ssh *ssh)
2082 {
2083 return ssh->state->interactive_mode &&
2084 sshbuf_len(ssh->state->output) < 256;
2085 }
2086
2087 void
ssh_packet_set_tos(struct ssh * ssh,int tos)2088 ssh_packet_set_tos(struct ssh *ssh, int tos)
2089 {
2090 if (!ssh_packet_connection_is_on_socket(ssh) || tos == INT_MAX)
2091 return;
2092 set_sock_tos(ssh->state->connection_in, tos);
2093 }
2094
2095 /* Informs that the current session is interactive. Sets IP flags for that. */
2096
2097 void
ssh_packet_set_interactive(struct ssh * ssh,int interactive,int qos_interactive,int qos_bulk)2098 ssh_packet_set_interactive(struct ssh *ssh, int interactive, int qos_interactive, int qos_bulk)
2099 {
2100 struct session_state *state = ssh->state;
2101
2102 if (state->set_interactive_called)
2103 return;
2104 state->set_interactive_called = 1;
2105
2106 /* Record that we are in interactive mode. */
2107 state->interactive_mode = interactive;
2108
2109 /* Only set socket options if using a socket. */
2110 if (!ssh_packet_connection_is_on_socket(ssh))
2111 return;
2112 set_nodelay(state->connection_in);
2113 ssh_packet_set_tos(ssh, interactive ? qos_interactive : qos_bulk);
2114 }
2115
2116 /* Returns true if the current connection is interactive. */
2117
2118 int
ssh_packet_is_interactive(struct ssh * ssh)2119 ssh_packet_is_interactive(struct ssh *ssh)
2120 {
2121 return ssh->state->interactive_mode;
2122 }
2123
2124 int
ssh_packet_set_maxsize(struct ssh * ssh,u_int s)2125 ssh_packet_set_maxsize(struct ssh *ssh, u_int s)
2126 {
2127 struct session_state *state = ssh->state;
2128
2129 if (state->set_maxsize_called) {
2130 logit_f("called twice: old %d new %d",
2131 state->max_packet_size, s);
2132 return -1;
2133 }
2134 if (s < 4 * 1024 || s > 1024 * 1024) {
2135 logit_f("bad size %d", s);
2136 return -1;
2137 }
2138 state->set_maxsize_called = 1;
2139 debug_f("setting to %d", s);
2140 state->max_packet_size = s;
2141 return s;
2142 }
2143
2144 int
ssh_packet_inc_alive_timeouts(struct ssh * ssh)2145 ssh_packet_inc_alive_timeouts(struct ssh *ssh)
2146 {
2147 return ++ssh->state->keep_alive_timeouts;
2148 }
2149
2150 void
ssh_packet_set_alive_timeouts(struct ssh * ssh,int ka)2151 ssh_packet_set_alive_timeouts(struct ssh *ssh, int ka)
2152 {
2153 ssh->state->keep_alive_timeouts = ka;
2154 }
2155
2156 u_int
ssh_packet_get_maxsize(struct ssh * ssh)2157 ssh_packet_get_maxsize(struct ssh *ssh)
2158 {
2159 return ssh->state->max_packet_size;
2160 }
2161
2162 void
ssh_packet_set_rekey_limits(struct ssh * ssh,u_int64_t bytes,u_int32_t seconds)2163 ssh_packet_set_rekey_limits(struct ssh *ssh, u_int64_t bytes, u_int32_t seconds)
2164 {
2165 debug3("rekey after %llu bytes, %u seconds", (unsigned long long)bytes,
2166 (unsigned int)seconds);
2167 ssh->state->rekey_limit = bytes;
2168 ssh->state->rekey_interval = seconds;
2169 }
2170
2171 time_t
ssh_packet_get_rekey_timeout(struct ssh * ssh)2172 ssh_packet_get_rekey_timeout(struct ssh *ssh)
2173 {
2174 time_t seconds;
2175
2176 seconds = ssh->state->rekey_time + ssh->state->rekey_interval -
2177 monotime();
2178 return (seconds <= 0 ? 1 : seconds);
2179 }
2180
2181 void
ssh_packet_set_server(struct ssh * ssh)2182 ssh_packet_set_server(struct ssh *ssh)
2183 {
2184 ssh->state->server_side = 1;
2185 ssh->kex->server = 1; /* XXX unify? */
2186 }
2187
2188 void
ssh_packet_set_authenticated(struct ssh * ssh)2189 ssh_packet_set_authenticated(struct ssh *ssh)
2190 {
2191 ssh->state->after_authentication = 1;
2192 }
2193
2194 void *
ssh_packet_get_input(struct ssh * ssh)2195 ssh_packet_get_input(struct ssh *ssh)
2196 {
2197 return (void *)ssh->state->input;
2198 }
2199
2200 void *
ssh_packet_get_output(struct ssh * ssh)2201 ssh_packet_get_output(struct ssh *ssh)
2202 {
2203 return (void *)ssh->state->output;
2204 }
2205
2206 /* Reset after_authentication and reset compression in post-auth privsep */
2207 static int
ssh_packet_set_postauth(struct ssh * ssh)2208 ssh_packet_set_postauth(struct ssh *ssh)
2209 {
2210 int r;
2211
2212 debug_f("called");
2213 /* This was set in net child, but is not visible in user child */
2214 ssh->state->after_authentication = 1;
2215 ssh->state->rekeying = 0;
2216 if ((r = ssh_packet_enable_delayed_compress(ssh)) != 0)
2217 return r;
2218 return 0;
2219 }
2220
2221 /* Packet state (de-)serialization for privsep */
2222
2223 /* turn kex into a blob for packet state serialization */
2224 static int
kex_to_blob(struct sshbuf * m,struct kex * kex)2225 kex_to_blob(struct sshbuf *m, struct kex *kex)
2226 {
2227 int r;
2228
2229 if ((r = sshbuf_put_u32(m, kex->we_need)) != 0 ||
2230 (r = sshbuf_put_cstring(m, kex->hostkey_alg)) != 0 ||
2231 (r = sshbuf_put_u32(m, kex->hostkey_type)) != 0 ||
2232 (r = sshbuf_put_u32(m, kex->hostkey_nid)) != 0 ||
2233 (r = sshbuf_put_u32(m, kex->kex_type)) != 0 ||
2234 (r = sshbuf_put_u32(m, kex->kex_strict)) != 0 ||
2235 (r = sshbuf_put_stringb(m, kex->my)) != 0 ||
2236 (r = sshbuf_put_stringb(m, kex->peer)) != 0 ||
2237 (r = sshbuf_put_stringb(m, kex->client_version)) != 0 ||
2238 (r = sshbuf_put_stringb(m, kex->server_version)) != 0 ||
2239 (r = sshbuf_put_stringb(m, kex->session_id)) != 0 ||
2240 (r = sshbuf_put_u32(m, kex->flags)) != 0)
2241 return r;
2242 return 0;
2243 }
2244
2245 /* turn key exchange results into a blob for packet state serialization */
2246 static int
newkeys_to_blob(struct sshbuf * m,struct ssh * ssh,int mode)2247 newkeys_to_blob(struct sshbuf *m, struct ssh *ssh, int mode)
2248 {
2249 struct sshbuf *b;
2250 struct sshcipher_ctx *cc;
2251 struct sshcomp *comp;
2252 struct sshenc *enc;
2253 struct sshmac *mac;
2254 struct newkeys *newkey;
2255 int r;
2256
2257 if ((newkey = ssh->state->newkeys[mode]) == NULL)
2258 return SSH_ERR_INTERNAL_ERROR;
2259 enc = &newkey->enc;
2260 mac = &newkey->mac;
2261 comp = &newkey->comp;
2262 cc = (mode == MODE_OUT) ? ssh->state->send_context :
2263 ssh->state->receive_context;
2264 if ((r = cipher_get_keyiv(cc, enc->iv, enc->iv_len)) != 0)
2265 return r;
2266 if ((b = sshbuf_new()) == NULL)
2267 return SSH_ERR_ALLOC_FAIL;
2268 if ((r = sshbuf_put_cstring(b, enc->name)) != 0 ||
2269 (r = sshbuf_put_u32(b, enc->enabled)) != 0 ||
2270 (r = sshbuf_put_u32(b, enc->block_size)) != 0 ||
2271 (r = sshbuf_put_string(b, enc->key, enc->key_len)) != 0 ||
2272 (r = sshbuf_put_string(b, enc->iv, enc->iv_len)) != 0)
2273 goto out;
2274 if (cipher_authlen(enc->cipher) == 0) {
2275 if ((r = sshbuf_put_cstring(b, mac->name)) != 0 ||
2276 (r = sshbuf_put_u32(b, mac->enabled)) != 0 ||
2277 (r = sshbuf_put_string(b, mac->key, mac->key_len)) != 0)
2278 goto out;
2279 }
2280 if ((r = sshbuf_put_u32(b, comp->type)) != 0 ||
2281 (r = sshbuf_put_cstring(b, comp->name)) != 0)
2282 goto out;
2283 r = sshbuf_put_stringb(m, b);
2284 out:
2285 sshbuf_free(b);
2286 return r;
2287 }
2288
2289 /* serialize packet state into a blob */
2290 int
ssh_packet_get_state(struct ssh * ssh,struct sshbuf * m)2291 ssh_packet_get_state(struct ssh *ssh, struct sshbuf *m)
2292 {
2293 struct session_state *state = ssh->state;
2294 int r;
2295
2296 if ((r = kex_to_blob(m, ssh->kex)) != 0 ||
2297 (r = newkeys_to_blob(m, ssh, MODE_OUT)) != 0 ||
2298 (r = newkeys_to_blob(m, ssh, MODE_IN)) != 0 ||
2299 (r = sshbuf_put_u64(m, state->rekey_limit)) != 0 ||
2300 (r = sshbuf_put_u32(m, state->rekey_interval)) != 0 ||
2301 (r = sshbuf_put_u32(m, state->p_send.seqnr)) != 0 ||
2302 (r = sshbuf_put_u64(m, state->p_send.blocks)) != 0 ||
2303 (r = sshbuf_put_u32(m, state->p_send.packets)) != 0 ||
2304 (r = sshbuf_put_u64(m, state->p_send.bytes)) != 0 ||
2305 (r = sshbuf_put_u32(m, state->p_read.seqnr)) != 0 ||
2306 (r = sshbuf_put_u64(m, state->p_read.blocks)) != 0 ||
2307 (r = sshbuf_put_u32(m, state->p_read.packets)) != 0 ||
2308 (r = sshbuf_put_u64(m, state->p_read.bytes)) != 0 ||
2309 (r = sshbuf_put_stringb(m, state->input)) != 0 ||
2310 (r = sshbuf_put_stringb(m, state->output)) != 0)
2311 return r;
2312
2313 return 0;
2314 }
2315
2316 /* restore key exchange results from blob for packet state de-serialization */
2317 static int
newkeys_from_blob(struct sshbuf * m,struct ssh * ssh,int mode)2318 newkeys_from_blob(struct sshbuf *m, struct ssh *ssh, int mode)
2319 {
2320 struct sshbuf *b = NULL;
2321 struct sshcomp *comp;
2322 struct sshenc *enc;
2323 struct sshmac *mac;
2324 struct newkeys *newkey = NULL;
2325 size_t keylen, ivlen, maclen;
2326 int r;
2327
2328 if ((newkey = calloc(1, sizeof(*newkey))) == NULL) {
2329 r = SSH_ERR_ALLOC_FAIL;
2330 goto out;
2331 }
2332 if ((r = sshbuf_froms(m, &b)) != 0)
2333 goto out;
2334 #ifdef DEBUG_PK
2335 sshbuf_dump(b, stderr);
2336 #endif
2337 enc = &newkey->enc;
2338 mac = &newkey->mac;
2339 comp = &newkey->comp;
2340
2341 if ((r = sshbuf_get_cstring(b, &enc->name, NULL)) != 0 ||
2342 (r = sshbuf_get_u32(b, (u_int *)&enc->enabled)) != 0 ||
2343 (r = sshbuf_get_u32(b, &enc->block_size)) != 0 ||
2344 (r = sshbuf_get_string(b, &enc->key, &keylen)) != 0 ||
2345 (r = sshbuf_get_string(b, &enc->iv, &ivlen)) != 0)
2346 goto out;
2347 if ((enc->cipher = cipher_by_name(enc->name)) == NULL) {
2348 r = SSH_ERR_INVALID_FORMAT;
2349 goto out;
2350 }
2351 if (cipher_authlen(enc->cipher) == 0) {
2352 if ((r = sshbuf_get_cstring(b, &mac->name, NULL)) != 0)
2353 goto out;
2354 if ((r = mac_setup(mac, mac->name)) != 0)
2355 goto out;
2356 if ((r = sshbuf_get_u32(b, (u_int *)&mac->enabled)) != 0 ||
2357 (r = sshbuf_get_string(b, &mac->key, &maclen)) != 0)
2358 goto out;
2359 if (maclen > mac->key_len) {
2360 r = SSH_ERR_INVALID_FORMAT;
2361 goto out;
2362 }
2363 mac->key_len = maclen;
2364 }
2365 if ((r = sshbuf_get_u32(b, &comp->type)) != 0 ||
2366 (r = sshbuf_get_cstring(b, &comp->name, NULL)) != 0)
2367 goto out;
2368 if (sshbuf_len(b) != 0) {
2369 r = SSH_ERR_INVALID_FORMAT;
2370 goto out;
2371 }
2372 enc->key_len = keylen;
2373 enc->iv_len = ivlen;
2374 ssh->kex->newkeys[mode] = newkey;
2375 newkey = NULL;
2376 r = 0;
2377 out:
2378 free(newkey);
2379 sshbuf_free(b);
2380 return r;
2381 }
2382
2383 /* restore kex from blob for packet state de-serialization */
2384 static int
kex_from_blob(struct sshbuf * m,struct kex ** kexp)2385 kex_from_blob(struct sshbuf *m, struct kex **kexp)
2386 {
2387 struct kex *kex;
2388 int r;
2389
2390 if ((kex = kex_new()) == NULL)
2391 return SSH_ERR_ALLOC_FAIL;
2392 if ((r = sshbuf_get_u32(m, &kex->we_need)) != 0 ||
2393 (r = sshbuf_get_cstring(m, &kex->hostkey_alg, NULL)) != 0 ||
2394 (r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_type)) != 0 ||
2395 (r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_nid)) != 0 ||
2396 (r = sshbuf_get_u32(m, &kex->kex_type)) != 0 ||
2397 (r = sshbuf_get_u32(m, &kex->kex_strict)) != 0 ||
2398 (r = sshbuf_get_stringb(m, kex->my)) != 0 ||
2399 (r = sshbuf_get_stringb(m, kex->peer)) != 0 ||
2400 (r = sshbuf_get_stringb(m, kex->client_version)) != 0 ||
2401 (r = sshbuf_get_stringb(m, kex->server_version)) != 0 ||
2402 (r = sshbuf_get_stringb(m, kex->session_id)) != 0 ||
2403 (r = sshbuf_get_u32(m, &kex->flags)) != 0)
2404 goto out;
2405 kex->server = 1;
2406 kex->done = 1;
2407 r = 0;
2408 out:
2409 if (r != 0 || kexp == NULL) {
2410 kex_free(kex);
2411 if (kexp != NULL)
2412 *kexp = NULL;
2413 } else {
2414 kex_free(*kexp);
2415 *kexp = kex;
2416 }
2417 return r;
2418 }
2419
2420 /*
2421 * Restore packet state from content of blob 'm' (de-serialization).
2422 * Note that 'm' will be partially consumed on parsing or any other errors.
2423 */
2424 int
ssh_packet_set_state(struct ssh * ssh,struct sshbuf * m)2425 ssh_packet_set_state(struct ssh *ssh, struct sshbuf *m)
2426 {
2427 struct session_state *state = ssh->state;
2428 const u_char *input, *output;
2429 size_t ilen, olen;
2430 int r;
2431
2432 if ((r = kex_from_blob(m, &ssh->kex)) != 0 ||
2433 (r = newkeys_from_blob(m, ssh, MODE_OUT)) != 0 ||
2434 (r = newkeys_from_blob(m, ssh, MODE_IN)) != 0 ||
2435 (r = sshbuf_get_u64(m, &state->rekey_limit)) != 0 ||
2436 (r = sshbuf_get_u32(m, &state->rekey_interval)) != 0 ||
2437 (r = sshbuf_get_u32(m, &state->p_send.seqnr)) != 0 ||
2438 (r = sshbuf_get_u64(m, &state->p_send.blocks)) != 0 ||
2439 (r = sshbuf_get_u32(m, &state->p_send.packets)) != 0 ||
2440 (r = sshbuf_get_u64(m, &state->p_send.bytes)) != 0 ||
2441 (r = sshbuf_get_u32(m, &state->p_read.seqnr)) != 0 ||
2442 (r = sshbuf_get_u64(m, &state->p_read.blocks)) != 0 ||
2443 (r = sshbuf_get_u32(m, &state->p_read.packets)) != 0 ||
2444 (r = sshbuf_get_u64(m, &state->p_read.bytes)) != 0)
2445 return r;
2446 /*
2447 * We set the time here so that in post-auth privsep child we
2448 * count from the completion of the authentication.
2449 */
2450 state->rekey_time = monotime();
2451 /* XXX ssh_set_newkeys overrides p_read.packets? XXX */
2452 if ((r = ssh_set_newkeys(ssh, MODE_IN)) != 0 ||
2453 (r = ssh_set_newkeys(ssh, MODE_OUT)) != 0)
2454 return r;
2455
2456 if ((r = ssh_packet_set_postauth(ssh)) != 0)
2457 return r;
2458
2459 sshbuf_reset(state->input);
2460 sshbuf_reset(state->output);
2461 if ((r = sshbuf_get_string_direct(m, &input, &ilen)) != 0 ||
2462 (r = sshbuf_get_string_direct(m, &output, &olen)) != 0 ||
2463 (r = sshbuf_put(state->input, input, ilen)) != 0 ||
2464 (r = sshbuf_put(state->output, output, olen)) != 0)
2465 return r;
2466
2467 if (sshbuf_len(m))
2468 return SSH_ERR_INVALID_FORMAT;
2469 debug3_f("done");
2470 return 0;
2471 }
2472
2473 /* NEW API */
2474
2475 /* put data to the outgoing packet */
2476
2477 int
sshpkt_put(struct ssh * ssh,const void * v,size_t len)2478 sshpkt_put(struct ssh *ssh, const void *v, size_t len)
2479 {
2480 return sshbuf_put(ssh->state->outgoing_packet, v, len);
2481 }
2482
2483 int
sshpkt_putb(struct ssh * ssh,const struct sshbuf * b)2484 sshpkt_putb(struct ssh *ssh, const struct sshbuf *b)
2485 {
2486 return sshbuf_putb(ssh->state->outgoing_packet, b);
2487 }
2488
2489 int
sshpkt_put_u8(struct ssh * ssh,u_char val)2490 sshpkt_put_u8(struct ssh *ssh, u_char val)
2491 {
2492 return sshbuf_put_u8(ssh->state->outgoing_packet, val);
2493 }
2494
2495 int
sshpkt_put_u32(struct ssh * ssh,u_int32_t val)2496 sshpkt_put_u32(struct ssh *ssh, u_int32_t val)
2497 {
2498 return sshbuf_put_u32(ssh->state->outgoing_packet, val);
2499 }
2500
2501 int
sshpkt_put_u64(struct ssh * ssh,u_int64_t val)2502 sshpkt_put_u64(struct ssh *ssh, u_int64_t val)
2503 {
2504 return sshbuf_put_u64(ssh->state->outgoing_packet, val);
2505 }
2506
2507 int
sshpkt_put_string(struct ssh * ssh,const void * v,size_t len)2508 sshpkt_put_string(struct ssh *ssh, const void *v, size_t len)
2509 {
2510 return sshbuf_put_string(ssh->state->outgoing_packet, v, len);
2511 }
2512
2513 int
sshpkt_put_cstring(struct ssh * ssh,const void * v)2514 sshpkt_put_cstring(struct ssh *ssh, const void *v)
2515 {
2516 return sshbuf_put_cstring(ssh->state->outgoing_packet, v);
2517 }
2518
2519 int
sshpkt_put_stringb(struct ssh * ssh,const struct sshbuf * v)2520 sshpkt_put_stringb(struct ssh *ssh, const struct sshbuf *v)
2521 {
2522 return sshbuf_put_stringb(ssh->state->outgoing_packet, v);
2523 }
2524
2525 #ifdef WITH_OPENSSL
2526 int
sshpkt_put_ec(struct ssh * ssh,const EC_POINT * v,const EC_GROUP * g)2527 sshpkt_put_ec(struct ssh *ssh, const EC_POINT *v, const EC_GROUP *g)
2528 {
2529 return sshbuf_put_ec(ssh->state->outgoing_packet, v, g);
2530 }
2531
2532
2533 int
sshpkt_put_bignum2(struct ssh * ssh,const BIGNUM * v)2534 sshpkt_put_bignum2(struct ssh *ssh, const BIGNUM *v)
2535 {
2536 return sshbuf_put_bignum2(ssh->state->outgoing_packet, v);
2537 }
2538 #endif /* WITH_OPENSSL */
2539
2540 /* fetch data from the incoming packet */
2541
2542 int
sshpkt_get(struct ssh * ssh,void * valp,size_t len)2543 sshpkt_get(struct ssh *ssh, void *valp, size_t len)
2544 {
2545 return sshbuf_get(ssh->state->incoming_packet, valp, len);
2546 }
2547
2548 int
sshpkt_get_u8(struct ssh * ssh,u_char * valp)2549 sshpkt_get_u8(struct ssh *ssh, u_char *valp)
2550 {
2551 return sshbuf_get_u8(ssh->state->incoming_packet, valp);
2552 }
2553
2554 int
sshpkt_get_u32(struct ssh * ssh,u_int32_t * valp)2555 sshpkt_get_u32(struct ssh *ssh, u_int32_t *valp)
2556 {
2557 return sshbuf_get_u32(ssh->state->incoming_packet, valp);
2558 }
2559
2560 int
sshpkt_get_u64(struct ssh * ssh,u_int64_t * valp)2561 sshpkt_get_u64(struct ssh *ssh, u_int64_t *valp)
2562 {
2563 return sshbuf_get_u64(ssh->state->incoming_packet, valp);
2564 }
2565
2566 int
sshpkt_get_string(struct ssh * ssh,u_char ** valp,size_t * lenp)2567 sshpkt_get_string(struct ssh *ssh, u_char **valp, size_t *lenp)
2568 {
2569 return sshbuf_get_string(ssh->state->incoming_packet, valp, lenp);
2570 }
2571
2572 int
sshpkt_get_string_direct(struct ssh * ssh,const u_char ** valp,size_t * lenp)2573 sshpkt_get_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp)
2574 {
2575 return sshbuf_get_string_direct(ssh->state->incoming_packet, valp, lenp);
2576 }
2577
2578 int
sshpkt_peek_string_direct(struct ssh * ssh,const u_char ** valp,size_t * lenp)2579 sshpkt_peek_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp)
2580 {
2581 return sshbuf_peek_string_direct(ssh->state->incoming_packet, valp, lenp);
2582 }
2583
2584 int
sshpkt_get_cstring(struct ssh * ssh,char ** valp,size_t * lenp)2585 sshpkt_get_cstring(struct ssh *ssh, char **valp, size_t *lenp)
2586 {
2587 return sshbuf_get_cstring(ssh->state->incoming_packet, valp, lenp);
2588 }
2589
2590 int
sshpkt_getb_froms(struct ssh * ssh,struct sshbuf ** valp)2591 sshpkt_getb_froms(struct ssh *ssh, struct sshbuf **valp)
2592 {
2593 return sshbuf_froms(ssh->state->incoming_packet, valp);
2594 }
2595
2596 #ifdef WITH_OPENSSL
2597 int
sshpkt_get_ec(struct ssh * ssh,EC_POINT * v,const EC_GROUP * g)2598 sshpkt_get_ec(struct ssh *ssh, EC_POINT *v, const EC_GROUP *g)
2599 {
2600 return sshbuf_get_ec(ssh->state->incoming_packet, v, g);
2601 }
2602
2603 int
sshpkt_get_bignum2(struct ssh * ssh,BIGNUM ** valp)2604 sshpkt_get_bignum2(struct ssh *ssh, BIGNUM **valp)
2605 {
2606 return sshbuf_get_bignum2(ssh->state->incoming_packet, valp);
2607 }
2608 #endif /* WITH_OPENSSL */
2609
2610 int
sshpkt_get_end(struct ssh * ssh)2611 sshpkt_get_end(struct ssh *ssh)
2612 {
2613 if (sshbuf_len(ssh->state->incoming_packet) > 0)
2614 return SSH_ERR_UNEXPECTED_TRAILING_DATA;
2615 return 0;
2616 }
2617
2618 const u_char *
sshpkt_ptr(struct ssh * ssh,size_t * lenp)2619 sshpkt_ptr(struct ssh *ssh, size_t *lenp)
2620 {
2621 if (lenp != NULL)
2622 *lenp = sshbuf_len(ssh->state->incoming_packet);
2623 return sshbuf_ptr(ssh->state->incoming_packet);
2624 }
2625
2626 /* start a new packet */
2627
2628 int
sshpkt_start(struct ssh * ssh,u_char type)2629 sshpkt_start(struct ssh *ssh, u_char type)
2630 {
2631 u_char buf[6]; /* u32 packet length, u8 pad len, u8 type */
2632
2633 DBG(debug("packet_start[%d]", type));
2634 memset(buf, 0, sizeof(buf));
2635 buf[sizeof(buf) - 1] = type;
2636 sshbuf_reset(ssh->state->outgoing_packet);
2637 return sshbuf_put(ssh->state->outgoing_packet, buf, sizeof(buf));
2638 }
2639
2640 static int
ssh_packet_send_mux(struct ssh * ssh)2641 ssh_packet_send_mux(struct ssh *ssh)
2642 {
2643 struct session_state *state = ssh->state;
2644 u_char type, *cp;
2645 size_t len;
2646 int r;
2647
2648 if (ssh->kex)
2649 return SSH_ERR_INTERNAL_ERROR;
2650 len = sshbuf_len(state->outgoing_packet);
2651 if (len < 6)
2652 return SSH_ERR_INTERNAL_ERROR;
2653 cp = sshbuf_mutable_ptr(state->outgoing_packet);
2654 type = cp[5];
2655 if (ssh_packet_log_type(type))
2656 debug3_f("type %u", type);
2657 /* drop everything, but the connection protocol */
2658 if (type >= SSH2_MSG_CONNECTION_MIN &&
2659 type <= SSH2_MSG_CONNECTION_MAX) {
2660 POKE_U32(cp, len - 4);
2661 if ((r = sshbuf_putb(state->output,
2662 state->outgoing_packet)) != 0)
2663 return r;
2664 /* sshbuf_dump(state->output, stderr); */
2665 }
2666 sshbuf_reset(state->outgoing_packet);
2667 return 0;
2668 }
2669
2670 /*
2671 * 9.2. Ignored Data Message
2672 *
2673 * byte SSH_MSG_IGNORE
2674 * string data
2675 *
2676 * All implementations MUST understand (and ignore) this message at any
2677 * time (after receiving the protocol version). No implementation is
2678 * required to send them. This message can be used as an additional
2679 * protection measure against advanced traffic analysis techniques.
2680 */
2681 int
sshpkt_msg_ignore(struct ssh * ssh,u_int nbytes)2682 sshpkt_msg_ignore(struct ssh *ssh, u_int nbytes)
2683 {
2684 u_int32_t rnd = 0;
2685 int r;
2686 u_int i;
2687
2688 if ((r = sshpkt_start(ssh, SSH2_MSG_IGNORE)) != 0 ||
2689 (r = sshpkt_put_u32(ssh, nbytes)) != 0)
2690 return r;
2691 for (i = 0; i < nbytes; i++) {
2692 if (i % 4 == 0)
2693 rnd = arc4random();
2694 if ((r = sshpkt_put_u8(ssh, (u_char)rnd & 0xff)) != 0)
2695 return r;
2696 rnd >>= 8;
2697 }
2698 return 0;
2699 }
2700
2701 /* send it */
2702
2703 int
sshpkt_send(struct ssh * ssh)2704 sshpkt_send(struct ssh *ssh)
2705 {
2706 if (ssh->state && ssh->state->mux)
2707 return ssh_packet_send_mux(ssh);
2708 return ssh_packet_send2(ssh);
2709 }
2710
2711 int
sshpkt_disconnect(struct ssh * ssh,const char * fmt,...)2712 sshpkt_disconnect(struct ssh *ssh, const char *fmt,...)
2713 {
2714 char buf[1024];
2715 va_list args;
2716 int r;
2717
2718 va_start(args, fmt);
2719 vsnprintf(buf, sizeof(buf), fmt, args);
2720 va_end(args);
2721
2722 debug2_f("sending SSH2_MSG_DISCONNECT: %s", buf);
2723 if ((r = sshpkt_start(ssh, SSH2_MSG_DISCONNECT)) != 0 ||
2724 (r = sshpkt_put_u32(ssh, SSH2_DISCONNECT_PROTOCOL_ERROR)) != 0 ||
2725 (r = sshpkt_put_cstring(ssh, buf)) != 0 ||
2726 (r = sshpkt_put_cstring(ssh, "")) != 0 ||
2727 (r = sshpkt_send(ssh)) != 0)
2728 return r;
2729 return 0;
2730 }
2731
2732 /* roundup current message to pad bytes */
2733 int
sshpkt_add_padding(struct ssh * ssh,u_char pad)2734 sshpkt_add_padding(struct ssh *ssh, u_char pad)
2735 {
2736 ssh->state->extra_pad = pad;
2737 return 0;
2738 }
2739