1/* $OpenBSD: packet.c,v 1.315 2024/05/31 08:49:35 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 88struct packet_state { 89 u_int32_t seqnr; 90 u_int32_t packets; 91 u_int64_t blocks; 92 u_int64_t bytes; 93}; 94 95struct packet { 96 TAILQ_ENTRY(packet) next; 97 u_char type; 98 struct sshbuf *payload; 99}; 100 101struct 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 209struct ssh * 210ssh_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 254void 255ssh_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 */ 262int 263ssh_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 */ 272struct ssh * 273ssh_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 309void 310ssh_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 324void 325ssh_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 333int 334ssh_packet_get_mux(struct ssh *ssh) 335{ 336 return ssh->state->mux; 337} 338 339int 340ssh_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 358int 359ssh_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 385static int 386ssh_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 413int 414ssh_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 446void 447ssh_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 455int 456ssh_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 463void 464ssh_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 475int 476ssh_packet_get_connection_in(struct ssh *ssh) 477{ 478 return ssh->state->connection_in; 479} 480 481/* Returns the descriptor used for writing. */ 482 483int 484ssh_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 494const char * 495ssh_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/* 518 * Returns the remote DNS hostname as a string. The returned string must not 519 * be freed. NB. this will usually trigger a DNS query. Return value is on 520 * heap and no caching is performed. 521 * This function does additional checks on the hostname to mitigate some 522 * attacks based on conflation of hostnames and addresses and will 523 * fall back to returning an address on error. 524 */ 525 526char * 527ssh_remote_hostname(struct ssh *ssh) 528{ 529 struct sockaddr_storage from; 530 socklen_t fromlen; 531 struct addrinfo hints, *ai, *aitop; 532 char name[NI_MAXHOST], ntop2[NI_MAXHOST]; 533 const char *ntop = ssh_remote_ipaddr(ssh); 534 535 /* Get IP address of client. */ 536 fromlen = sizeof(from); 537 memset(&from, 0, sizeof(from)); 538 if (getpeername(ssh_packet_get_connection_in(ssh), 539 (struct sockaddr *)&from, &fromlen) == -1) { 540 debug_f("getpeername failed: %.100s", strerror(errno)); 541 return xstrdup(ntop); 542 } 543 544 debug3_f("trying to reverse map address %.100s.", ntop); 545 /* Map the IP address to a host name. */ 546 if (getnameinfo((struct sockaddr *)&from, fromlen, name, sizeof(name), 547 NULL, 0, NI_NAMEREQD) != 0) { 548 /* Host name not found. Use ip address. */ 549 return xstrdup(ntop); 550 } 551 552 /* 553 * if reverse lookup result looks like a numeric hostname, 554 * someone is trying to trick us by PTR record like following: 555 * 1.1.1.10.in-addr.arpa. IN PTR 2.3.4.5 556 */ 557 memset(&hints, 0, sizeof(hints)); 558 hints.ai_socktype = SOCK_DGRAM; /*dummy*/ 559 hints.ai_flags = AI_NUMERICHOST; 560 if (getaddrinfo(name, NULL, &hints, &ai) == 0) { 561 logit("Nasty PTR record \"%s\" is set up for %s, ignoring", 562 name, ntop); 563 freeaddrinfo(ai); 564 return xstrdup(ntop); 565 } 566 567 /* Names are stored in lowercase. */ 568 lowercase(name); 569 570 /* 571 * Map it back to an IP address and check that the given 572 * address actually is an address of this host. This is 573 * necessary because anyone with access to a name server can 574 * define arbitrary names for an IP address. Mapping from 575 * name to IP address can be trusted better (but can still be 576 * fooled if the intruder has access to the name server of 577 * the domain). 578 */ 579 memset(&hints, 0, sizeof(hints)); 580 hints.ai_family = from.ss_family; 581 hints.ai_socktype = SOCK_STREAM; 582 if (getaddrinfo(name, NULL, &hints, &aitop) != 0) { 583 logit("reverse mapping checking getaddrinfo for %.700s " 584 "[%s] failed.", name, ntop); 585 return xstrdup(ntop); 586 } 587 /* Look for the address from the list of addresses. */ 588 for (ai = aitop; ai; ai = ai->ai_next) { 589 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop2, 590 sizeof(ntop2), NULL, 0, NI_NUMERICHOST) == 0 && 591 (strcmp(ntop, ntop2) == 0)) 592 break; 593 } 594 freeaddrinfo(aitop); 595 /* If we reached the end of the list, the address was not there. */ 596 if (ai == NULL) { 597 /* Address not found for the host name. */ 598 logit("Address %.100s maps to %.600s, but this does not " 599 "map back to the address.", ntop, name); 600 return xstrdup(ntop); 601 } 602 return xstrdup(name); 603} 604 605/* Returns the port number of the remote host. */ 606 607int 608ssh_remote_port(struct ssh *ssh) 609{ 610 (void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */ 611 return ssh->remote_port; 612} 613 614/* 615 * Returns the IP-address of the local host as a string. The returned 616 * string must not be freed. 617 */ 618 619const char * 620ssh_local_ipaddr(struct ssh *ssh) 621{ 622 (void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */ 623 return ssh->local_ipaddr; 624} 625 626/* Returns the port number of the local host. */ 627 628int 629ssh_local_port(struct ssh *ssh) 630{ 631 (void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */ 632 return ssh->local_port; 633} 634 635/* Returns the routing domain of the input socket, or NULL if unavailable */ 636const char * 637ssh_packet_rdomain_in(struct ssh *ssh) 638{ 639 if (ssh->rdomain_in != NULL) 640 return ssh->rdomain_in; 641 if (!ssh_packet_connection_is_on_socket(ssh)) 642 return NULL; 643 ssh->rdomain_in = get_rdomain(ssh->state->connection_in); 644 return ssh->rdomain_in; 645} 646 647/* Closes the connection and clears and frees internal data structures. */ 648 649static void 650ssh_packet_close_internal(struct ssh *ssh, int do_close) 651{ 652 struct session_state *state = ssh->state; 653 u_int mode; 654 655 if (!state->initialized) 656 return; 657 state->initialized = 0; 658 if (do_close) { 659 if (state->connection_in == state->connection_out) { 660 close(state->connection_out); 661 } else { 662 close(state->connection_in); 663 close(state->connection_out); 664 } 665 } 666 sshbuf_free(state->input); 667 sshbuf_free(state->output); 668 sshbuf_free(state->outgoing_packet); 669 sshbuf_free(state->incoming_packet); 670 for (mode = 0; mode < MODE_MAX; mode++) { 671 kex_free_newkeys(state->newkeys[mode]); /* current keys */ 672 state->newkeys[mode] = NULL; 673 ssh_clear_newkeys(ssh, mode); /* next keys */ 674 } 675#ifdef WITH_ZLIB 676 /* compression state is in shared mem, so we can only release it once */ 677 if (do_close && state->compression_buffer) { 678 sshbuf_free(state->compression_buffer); 679 if (state->compression_out_started) { 680 z_streamp stream = &state->compression_out_stream; 681 debug("compress outgoing: " 682 "raw data %llu, compressed %llu, factor %.2f", 683 (unsigned long long)stream->total_in, 684 (unsigned long long)stream->total_out, 685 stream->total_in == 0 ? 0.0 : 686 (double) stream->total_out / stream->total_in); 687 if (state->compression_out_failures == 0) 688 deflateEnd(stream); 689 } 690 if (state->compression_in_started) { 691 z_streamp stream = &state->compression_in_stream; 692 debug("compress incoming: " 693 "raw data %llu, compressed %llu, factor %.2f", 694 (unsigned long long)stream->total_out, 695 (unsigned long long)stream->total_in, 696 stream->total_out == 0 ? 0.0 : 697 (double) stream->total_in / stream->total_out); 698 if (state->compression_in_failures == 0) 699 inflateEnd(stream); 700 } 701 } 702#endif /* WITH_ZLIB */ 703 cipher_free(state->send_context); 704 cipher_free(state->receive_context); 705 state->send_context = state->receive_context = NULL; 706 if (do_close) { 707 free(ssh->local_ipaddr); 708 ssh->local_ipaddr = NULL; 709 free(ssh->remote_ipaddr); 710 ssh->remote_ipaddr = NULL; 711 free(ssh->state); 712 ssh->state = NULL; 713 kex_free(ssh->kex); 714 ssh->kex = NULL; 715 } 716} 717 718void 719ssh_packet_close(struct ssh *ssh) 720{ 721 ssh_packet_close_internal(ssh, 1); 722} 723 724void 725ssh_packet_clear_keys(struct ssh *ssh) 726{ 727 ssh_packet_close_internal(ssh, 0); 728} 729 730/* Sets remote side protocol flags. */ 731 732void 733ssh_packet_set_protocol_flags(struct ssh *ssh, u_int protocol_flags) 734{ 735 ssh->state->remote_protocol_flags = protocol_flags; 736} 737 738/* Returns the remote protocol flags set earlier by the above function. */ 739 740u_int 741ssh_packet_get_protocol_flags(struct ssh *ssh) 742{ 743 return ssh->state->remote_protocol_flags; 744} 745 746/* 747 * Starts packet compression from the next packet on in both directions. 748 * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip. 749 */ 750 751static int 752ssh_packet_init_compression(struct ssh *ssh) 753{ 754 if (!ssh->state->compression_buffer && 755 ((ssh->state->compression_buffer = sshbuf_new()) == NULL)) 756 return SSH_ERR_ALLOC_FAIL; 757 return 0; 758} 759 760#ifdef WITH_ZLIB 761static int 762start_compression_out(struct ssh *ssh, int level) 763{ 764 if (level < 1 || level > 9) 765 return SSH_ERR_INVALID_ARGUMENT; 766 debug("Enabling compression at level %d.", level); 767 if (ssh->state->compression_out_started == 1) 768 deflateEnd(&ssh->state->compression_out_stream); 769 switch (deflateInit(&ssh->state->compression_out_stream, level)) { 770 case Z_OK: 771 ssh->state->compression_out_started = 1; 772 break; 773 case Z_MEM_ERROR: 774 return SSH_ERR_ALLOC_FAIL; 775 default: 776 return SSH_ERR_INTERNAL_ERROR; 777 } 778 return 0; 779} 780 781static int 782start_compression_in(struct ssh *ssh) 783{ 784 if (ssh->state->compression_in_started == 1) 785 inflateEnd(&ssh->state->compression_in_stream); 786 switch (inflateInit(&ssh->state->compression_in_stream)) { 787 case Z_OK: 788 ssh->state->compression_in_started = 1; 789 break; 790 case Z_MEM_ERROR: 791 return SSH_ERR_ALLOC_FAIL; 792 default: 793 return SSH_ERR_INTERNAL_ERROR; 794 } 795 return 0; 796} 797 798/* XXX remove need for separate compression buffer */ 799static int 800compress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out) 801{ 802 u_char buf[4096]; 803 int r, status; 804 805 if (ssh->state->compression_out_started != 1) 806 return SSH_ERR_INTERNAL_ERROR; 807 808 /* This case is not handled below. */ 809 if (sshbuf_len(in) == 0) 810 return 0; 811 812 /* Input is the contents of the input buffer. */ 813 if ((ssh->state->compression_out_stream.next_in = 814 sshbuf_mutable_ptr(in)) == NULL) 815 return SSH_ERR_INTERNAL_ERROR; 816 ssh->state->compression_out_stream.avail_in = sshbuf_len(in); 817 818 /* Loop compressing until deflate() returns with avail_out != 0. */ 819 do { 820 /* Set up fixed-size output buffer. */ 821 ssh->state->compression_out_stream.next_out = buf; 822 ssh->state->compression_out_stream.avail_out = sizeof(buf); 823 824 /* Compress as much data into the buffer as possible. */ 825 status = deflate(&ssh->state->compression_out_stream, 826 Z_PARTIAL_FLUSH); 827 switch (status) { 828 case Z_MEM_ERROR: 829 return SSH_ERR_ALLOC_FAIL; 830 case Z_OK: 831 /* Append compressed data to output_buffer. */ 832 if ((r = sshbuf_put(out, buf, sizeof(buf) - 833 ssh->state->compression_out_stream.avail_out)) != 0) 834 return r; 835 break; 836 case Z_STREAM_ERROR: 837 default: 838 ssh->state->compression_out_failures++; 839 return SSH_ERR_INVALID_FORMAT; 840 } 841 } while (ssh->state->compression_out_stream.avail_out == 0); 842 return 0; 843} 844 845static int 846uncompress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out) 847{ 848 u_char buf[4096]; 849 int r, status; 850 851 if (ssh->state->compression_in_started != 1) 852 return SSH_ERR_INTERNAL_ERROR; 853 854 if ((ssh->state->compression_in_stream.next_in = 855 sshbuf_mutable_ptr(in)) == NULL) 856 return SSH_ERR_INTERNAL_ERROR; 857 ssh->state->compression_in_stream.avail_in = sshbuf_len(in); 858 859 for (;;) { 860 /* Set up fixed-size output buffer. */ 861 ssh->state->compression_in_stream.next_out = buf; 862 ssh->state->compression_in_stream.avail_out = sizeof(buf); 863 864 status = inflate(&ssh->state->compression_in_stream, 865 Z_SYNC_FLUSH); 866 switch (status) { 867 case Z_OK: 868 if ((r = sshbuf_put(out, buf, sizeof(buf) - 869 ssh->state->compression_in_stream.avail_out)) != 0) 870 return r; 871 break; 872 case Z_BUF_ERROR: 873 /* 874 * Comments in zlib.h say that we should keep calling 875 * inflate() until we get an error. This appears to 876 * be the error that we get. 877 */ 878 return 0; 879 case Z_DATA_ERROR: 880 return SSH_ERR_INVALID_FORMAT; 881 case Z_MEM_ERROR: 882 return SSH_ERR_ALLOC_FAIL; 883 case Z_STREAM_ERROR: 884 default: 885 ssh->state->compression_in_failures++; 886 return SSH_ERR_INTERNAL_ERROR; 887 } 888 } 889 /* NOTREACHED */ 890} 891 892#else /* WITH_ZLIB */ 893 894static int 895start_compression_out(struct ssh *ssh, int level) 896{ 897 return SSH_ERR_INTERNAL_ERROR; 898} 899 900static int 901start_compression_in(struct ssh *ssh) 902{ 903 return SSH_ERR_INTERNAL_ERROR; 904} 905 906static int 907compress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out) 908{ 909 return SSH_ERR_INTERNAL_ERROR; 910} 911 912static int 913uncompress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out) 914{ 915 return SSH_ERR_INTERNAL_ERROR; 916} 917#endif /* WITH_ZLIB */ 918 919void 920ssh_clear_newkeys(struct ssh *ssh, int mode) 921{ 922 if (ssh->kex && ssh->kex->newkeys[mode]) { 923 kex_free_newkeys(ssh->kex->newkeys[mode]); 924 ssh->kex->newkeys[mode] = NULL; 925 } 926} 927 928int 929ssh_set_newkeys(struct ssh *ssh, int mode) 930{ 931 struct session_state *state = ssh->state; 932 struct sshenc *enc; 933 struct sshmac *mac; 934 struct sshcomp *comp; 935 struct sshcipher_ctx **ccp; 936 struct packet_state *ps; 937 u_int64_t *max_blocks; 938 const char *wmsg; 939 int r, crypt_type; 940 const char *dir = mode == MODE_OUT ? "out" : "in"; 941 942 debug2_f("mode %d", mode); 943 944 if (mode == MODE_OUT) { 945 ccp = &state->send_context; 946 crypt_type = CIPHER_ENCRYPT; 947 ps = &state->p_send; 948 max_blocks = &state->max_blocks_out; 949 } else { 950 ccp = &state->receive_context; 951 crypt_type = CIPHER_DECRYPT; 952 ps = &state->p_read; 953 max_blocks = &state->max_blocks_in; 954 } 955 if (state->newkeys[mode] != NULL) { 956 debug_f("rekeying %s, input %llu bytes %llu blocks, " 957 "output %llu bytes %llu blocks", dir, 958 (unsigned long long)state->p_read.bytes, 959 (unsigned long long)state->p_read.blocks, 960 (unsigned long long)state->p_send.bytes, 961 (unsigned long long)state->p_send.blocks); 962 kex_free_newkeys(state->newkeys[mode]); 963 state->newkeys[mode] = NULL; 964 } 965 /* note that both bytes and the seqnr are not reset */ 966 ps->packets = ps->blocks = 0; 967 /* move newkeys from kex to state */ 968 if ((state->newkeys[mode] = ssh->kex->newkeys[mode]) == NULL) 969 return SSH_ERR_INTERNAL_ERROR; 970 ssh->kex->newkeys[mode] = NULL; 971 enc = &state->newkeys[mode]->enc; 972 mac = &state->newkeys[mode]->mac; 973 comp = &state->newkeys[mode]->comp; 974 if (cipher_authlen(enc->cipher) == 0) { 975 if ((r = mac_init(mac)) != 0) 976 return r; 977 } 978 mac->enabled = 1; 979 DBG(debug_f("cipher_init: %s", dir)); 980 cipher_free(*ccp); 981 *ccp = NULL; 982 if ((r = cipher_init(ccp, enc->cipher, enc->key, enc->key_len, 983 enc->iv, enc->iv_len, crypt_type)) != 0) 984 return r; 985 if (!state->cipher_warning_done && 986 (wmsg = cipher_warning_message(*ccp)) != NULL) { 987 error("Warning: %s", wmsg); 988 state->cipher_warning_done = 1; 989 } 990 /* Deleting the keys does not gain extra security */ 991 /* explicit_bzero(enc->iv, enc->block_size); 992 explicit_bzero(enc->key, enc->key_len); 993 explicit_bzero(mac->key, mac->key_len); */ 994 if ((comp->type == COMP_ZLIB || 995 (comp->type == COMP_DELAYED && 996 state->after_authentication)) && comp->enabled == 0) { 997 if ((r = ssh_packet_init_compression(ssh)) < 0) 998 return r; 999 if (mode == MODE_OUT) { 1000 if ((r = start_compression_out(ssh, 6)) != 0) 1001 return r; 1002 } else { 1003 if ((r = start_compression_in(ssh)) != 0) 1004 return r; 1005 } 1006 comp->enabled = 1; 1007 } 1008 /* 1009 * The 2^(blocksize*2) limit is too expensive for 3DES, 1010 * so enforce a 1GB limit for small blocksizes. 1011 * See RFC4344 section 3.2. 1012 */ 1013 if (enc->block_size >= 16) 1014 *max_blocks = (u_int64_t)1 << (enc->block_size*2); 1015 else 1016 *max_blocks = ((u_int64_t)1 << 30) / enc->block_size; 1017 if (state->rekey_limit) 1018 *max_blocks = MINIMUM(*max_blocks, 1019 state->rekey_limit / enc->block_size); 1020 debug("rekey %s after %llu blocks", dir, 1021 (unsigned long long)*max_blocks); 1022 return 0; 1023} 1024 1025#define MAX_PACKETS (1U<<31) 1026static int 1027ssh_packet_need_rekeying(struct ssh *ssh, u_int outbound_packet_len) 1028{ 1029 struct session_state *state = ssh->state; 1030 u_int32_t out_blocks; 1031 1032 /* XXX client can't cope with rekeying pre-auth */ 1033 if (!state->after_authentication) 1034 return 0; 1035 1036 /* Haven't keyed yet or KEX in progress. */ 1037 if (ssh_packet_is_rekeying(ssh)) 1038 return 0; 1039 1040 /* Peer can't rekey */ 1041 if (ssh->compat & SSH_BUG_NOREKEY) 1042 return 0; 1043 1044 /* 1045 * Permit one packet in or out per rekey - this allows us to 1046 * make progress when rekey limits are very small. 1047 */ 1048 if (state->p_send.packets == 0 && state->p_read.packets == 0) 1049 return 0; 1050 1051 /* Time-based rekeying */ 1052 if (state->rekey_interval != 0 && 1053 (int64_t)state->rekey_time + state->rekey_interval <= monotime()) 1054 return 1; 1055 1056 /* 1057 * Always rekey when MAX_PACKETS sent in either direction 1058 * As per RFC4344 section 3.1 we do this after 2^31 packets. 1059 */ 1060 if (state->p_send.packets > MAX_PACKETS || 1061 state->p_read.packets > MAX_PACKETS) 1062 return 1; 1063 1064 /* Rekey after (cipher-specific) maximum blocks */ 1065 out_blocks = ROUNDUP(outbound_packet_len, 1066 state->newkeys[MODE_OUT]->enc.block_size); 1067 return (state->max_blocks_out && 1068 (state->p_send.blocks + out_blocks > state->max_blocks_out)) || 1069 (state->max_blocks_in && 1070 (state->p_read.blocks > state->max_blocks_in)); 1071} 1072 1073int 1074ssh_packet_check_rekey(struct ssh *ssh) 1075{ 1076 if (!ssh_packet_need_rekeying(ssh, 0)) 1077 return 0; 1078 debug3_f("rekex triggered"); 1079 return kex_start_rekex(ssh); 1080} 1081 1082/* 1083 * Delayed compression for SSH2 is enabled after authentication: 1084 * This happens on the server side after a SSH2_MSG_USERAUTH_SUCCESS is sent, 1085 * and on the client side after a SSH2_MSG_USERAUTH_SUCCESS is received. 1086 */ 1087static int 1088ssh_packet_enable_delayed_compress(struct ssh *ssh) 1089{ 1090 struct session_state *state = ssh->state; 1091 struct sshcomp *comp = NULL; 1092 int r, mode; 1093 1094 /* 1095 * Remember that we are past the authentication step, so rekeying 1096 * with COMP_DELAYED will turn on compression immediately. 1097 */ 1098 state->after_authentication = 1; 1099 for (mode = 0; mode < MODE_MAX; mode++) { 1100 /* protocol error: USERAUTH_SUCCESS received before NEWKEYS */ 1101 if (state->newkeys[mode] == NULL) 1102 continue; 1103 comp = &state->newkeys[mode]->comp; 1104 if (comp && !comp->enabled && comp->type == COMP_DELAYED) { 1105 if ((r = ssh_packet_init_compression(ssh)) != 0) 1106 return r; 1107 if (mode == MODE_OUT) { 1108 if ((r = start_compression_out(ssh, 6)) != 0) 1109 return r; 1110 } else { 1111 if ((r = start_compression_in(ssh)) != 0) 1112 return r; 1113 } 1114 comp->enabled = 1; 1115 } 1116 } 1117 return 0; 1118} 1119 1120/* Used to mute debug logging for noisy packet types */ 1121int 1122ssh_packet_log_type(u_char type) 1123{ 1124 switch (type) { 1125 case SSH2_MSG_PING: 1126 case SSH2_MSG_PONG: 1127 case SSH2_MSG_CHANNEL_DATA: 1128 case SSH2_MSG_CHANNEL_EXTENDED_DATA: 1129 case SSH2_MSG_CHANNEL_WINDOW_ADJUST: 1130 return 0; 1131 default: 1132 return 1; 1133 } 1134} 1135 1136/* 1137 * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue) 1138 */ 1139int 1140ssh_packet_send2_wrapped(struct ssh *ssh) 1141{ 1142 struct session_state *state = ssh->state; 1143 u_char type, *cp, macbuf[SSH_DIGEST_MAX_LENGTH]; 1144 u_char tmp, padlen, pad = 0; 1145 u_int authlen = 0, aadlen = 0; 1146 u_int len; 1147 struct sshenc *enc = NULL; 1148 struct sshmac *mac = NULL; 1149 struct sshcomp *comp = NULL; 1150 int r, block_size; 1151 1152 if (state->newkeys[MODE_OUT] != NULL) { 1153 enc = &state->newkeys[MODE_OUT]->enc; 1154 mac = &state->newkeys[MODE_OUT]->mac; 1155 comp = &state->newkeys[MODE_OUT]->comp; 1156 /* disable mac for authenticated encryption */ 1157 if ((authlen = cipher_authlen(enc->cipher)) != 0) 1158 mac = NULL; 1159 } 1160 block_size = enc ? enc->block_size : 8; 1161 aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0; 1162 1163 type = (sshbuf_ptr(state->outgoing_packet))[5]; 1164 if (ssh_packet_log_type(type)) 1165 debug3("send packet: type %u", type); 1166#ifdef PACKET_DEBUG 1167 fprintf(stderr, "plain: "); 1168 sshbuf_dump(state->outgoing_packet, stderr); 1169#endif 1170 1171 if (comp && comp->enabled) { 1172 len = sshbuf_len(state->outgoing_packet); 1173 /* skip header, compress only payload */ 1174 if ((r = sshbuf_consume(state->outgoing_packet, 5)) != 0) 1175 goto out; 1176 sshbuf_reset(state->compression_buffer); 1177 if ((r = compress_buffer(ssh, state->outgoing_packet, 1178 state->compression_buffer)) != 0) 1179 goto out; 1180 sshbuf_reset(state->outgoing_packet); 1181 if ((r = sshbuf_put(state->outgoing_packet, 1182 "\0\0\0\0\0", 5)) != 0 || 1183 (r = sshbuf_putb(state->outgoing_packet, 1184 state->compression_buffer)) != 0) 1185 goto out; 1186 DBG(debug("compression: raw %d compressed %zd", len, 1187 sshbuf_len(state->outgoing_packet))); 1188 } 1189 1190 /* sizeof (packet_len + pad_len + payload) */ 1191 len = sshbuf_len(state->outgoing_packet); 1192 1193 /* 1194 * calc size of padding, alloc space, get random data, 1195 * minimum padding is 4 bytes 1196 */ 1197 len -= aadlen; /* packet length is not encrypted for EtM modes */ 1198 padlen = block_size - (len % block_size); 1199 if (padlen < 4) 1200 padlen += block_size; 1201 if (state->extra_pad) { 1202 tmp = state->extra_pad; 1203 state->extra_pad = 1204 ROUNDUP(state->extra_pad, block_size); 1205 /* check if roundup overflowed */ 1206 if (state->extra_pad < tmp) 1207 return SSH_ERR_INVALID_ARGUMENT; 1208 tmp = (len + padlen) % state->extra_pad; 1209 /* Check whether pad calculation below will underflow */ 1210 if (tmp > state->extra_pad) 1211 return SSH_ERR_INVALID_ARGUMENT; 1212 pad = state->extra_pad - tmp; 1213 DBG(debug3_f("adding %d (len %d padlen %d extra_pad %d)", 1214 pad, len, padlen, state->extra_pad)); 1215 tmp = padlen; 1216 padlen += pad; 1217 /* Check whether padlen calculation overflowed */ 1218 if (padlen < tmp) 1219 return SSH_ERR_INVALID_ARGUMENT; /* overflow */ 1220 state->extra_pad = 0; 1221 } 1222 if ((r = sshbuf_reserve(state->outgoing_packet, padlen, &cp)) != 0) 1223 goto out; 1224 if (enc && !cipher_ctx_is_plaintext(state->send_context)) { 1225 /* random padding */ 1226 arc4random_buf(cp, padlen); 1227 } else { 1228 /* clear padding */ 1229 explicit_bzero(cp, padlen); 1230 } 1231 /* sizeof (packet_len + pad_len + payload + padding) */ 1232 len = sshbuf_len(state->outgoing_packet); 1233 cp = sshbuf_mutable_ptr(state->outgoing_packet); 1234 if (cp == NULL) { 1235 r = SSH_ERR_INTERNAL_ERROR; 1236 goto out; 1237 } 1238 /* packet_length includes payload, padding and padding length field */ 1239 POKE_U32(cp, len - 4); 1240 cp[4] = padlen; 1241 DBG(debug("send: len %d (includes padlen %d, aadlen %d)", 1242 len, padlen, aadlen)); 1243 1244 /* compute MAC over seqnr and packet(length fields, payload, padding) */ 1245 if (mac && mac->enabled && !mac->etm) { 1246 if ((r = mac_compute(mac, state->p_send.seqnr, 1247 sshbuf_ptr(state->outgoing_packet), len, 1248 macbuf, sizeof(macbuf))) != 0) 1249 goto out; 1250 DBG(debug("done calc MAC out #%d", state->p_send.seqnr)); 1251 } 1252 /* encrypt packet and append to output buffer. */ 1253 if ((r = sshbuf_reserve(state->output, 1254 sshbuf_len(state->outgoing_packet) + authlen, &cp)) != 0) 1255 goto out; 1256 if ((r = cipher_crypt(state->send_context, state->p_send.seqnr, cp, 1257 sshbuf_ptr(state->outgoing_packet), 1258 len - aadlen, aadlen, authlen)) != 0) 1259 goto out; 1260 /* append unencrypted MAC */ 1261 if (mac && mac->enabled) { 1262 if (mac->etm) { 1263 /* EtM: compute mac over aadlen + cipher text */ 1264 if ((r = mac_compute(mac, state->p_send.seqnr, 1265 cp, len, macbuf, sizeof(macbuf))) != 0) 1266 goto out; 1267 DBG(debug("done calc MAC(EtM) out #%d", 1268 state->p_send.seqnr)); 1269 } 1270 if ((r = sshbuf_put(state->output, macbuf, mac->mac_len)) != 0) 1271 goto out; 1272 } 1273#ifdef PACKET_DEBUG 1274 fprintf(stderr, "encrypted: "); 1275 sshbuf_dump(state->output, stderr); 1276#endif 1277 /* increment sequence number for outgoing packets */ 1278 if (++state->p_send.seqnr == 0) { 1279 if ((ssh->kex->flags & KEX_INITIAL) != 0) { 1280 ssh_packet_disconnect(ssh, "outgoing sequence number " 1281 "wrapped during initial key exchange"); 1282 } 1283 logit("outgoing seqnr wraps around"); 1284 } 1285 if (++state->p_send.packets == 0) 1286 if (!(ssh->compat & SSH_BUG_NOREKEY)) 1287 return SSH_ERR_NEED_REKEY; 1288 state->p_send.blocks += len / block_size; 1289 state->p_send.bytes += len; 1290 sshbuf_reset(state->outgoing_packet); 1291 1292 if (type == SSH2_MSG_NEWKEYS && ssh->kex->kex_strict) { 1293 debug_f("resetting send seqnr %u", state->p_send.seqnr); 1294 state->p_send.seqnr = 0; 1295 } 1296 1297 if (type == SSH2_MSG_NEWKEYS) 1298 r = ssh_set_newkeys(ssh, MODE_OUT); 1299 else if (type == SSH2_MSG_USERAUTH_SUCCESS && state->server_side) 1300 r = ssh_packet_enable_delayed_compress(ssh); 1301 else 1302 r = 0; 1303 out: 1304 return r; 1305} 1306 1307/* returns non-zero if the specified packet type is usec by KEX */ 1308static int 1309ssh_packet_type_is_kex(u_char type) 1310{ 1311 return 1312 type >= SSH2_MSG_TRANSPORT_MIN && 1313 type <= SSH2_MSG_TRANSPORT_MAX && 1314 type != SSH2_MSG_SERVICE_REQUEST && 1315 type != SSH2_MSG_SERVICE_ACCEPT && 1316 type != SSH2_MSG_EXT_INFO; 1317} 1318 1319int 1320ssh_packet_send2(struct ssh *ssh) 1321{ 1322 struct session_state *state = ssh->state; 1323 struct packet *p; 1324 u_char type; 1325 int r, need_rekey; 1326 1327 if (sshbuf_len(state->outgoing_packet) < 6) 1328 return SSH_ERR_INTERNAL_ERROR; 1329 type = sshbuf_ptr(state->outgoing_packet)[5]; 1330 need_rekey = !ssh_packet_type_is_kex(type) && 1331 ssh_packet_need_rekeying(ssh, sshbuf_len(state->outgoing_packet)); 1332 1333 /* 1334 * During rekeying we can only send key exchange messages. 1335 * Queue everything else. 1336 */ 1337 if ((need_rekey || state->rekeying) && !ssh_packet_type_is_kex(type)) { 1338 if (need_rekey) 1339 debug3_f("rekex triggered"); 1340 debug("enqueue packet: %u", type); 1341 p = calloc(1, sizeof(*p)); 1342 if (p == NULL) 1343 return SSH_ERR_ALLOC_FAIL; 1344 p->type = type; 1345 p->payload = state->outgoing_packet; 1346 TAILQ_INSERT_TAIL(&state->outgoing, p, next); 1347 state->outgoing_packet = sshbuf_new(); 1348 if (state->outgoing_packet == NULL) 1349 return SSH_ERR_ALLOC_FAIL; 1350 if (need_rekey) { 1351 /* 1352 * This packet triggered a rekey, so send the 1353 * KEXINIT now. 1354 * NB. reenters this function via kex_start_rekex(). 1355 */ 1356 return kex_start_rekex(ssh); 1357 } 1358 return 0; 1359 } 1360 1361 /* rekeying starts with sending KEXINIT */ 1362 if (type == SSH2_MSG_KEXINIT) 1363 state->rekeying = 1; 1364 1365 if ((r = ssh_packet_send2_wrapped(ssh)) != 0) 1366 return r; 1367 1368 /* after a NEWKEYS message we can send the complete queue */ 1369 if (type == SSH2_MSG_NEWKEYS) { 1370 state->rekeying = 0; 1371 state->rekey_time = monotime(); 1372 while ((p = TAILQ_FIRST(&state->outgoing))) { 1373 type = p->type; 1374 /* 1375 * If this packet triggers a rekex, then skip the 1376 * remaining packets in the queue for now. 1377 * NB. re-enters this function via kex_start_rekex. 1378 */ 1379 if (ssh_packet_need_rekeying(ssh, 1380 sshbuf_len(p->payload))) { 1381 debug3_f("queued packet triggered rekex"); 1382 return kex_start_rekex(ssh); 1383 } 1384 debug("dequeue packet: %u", type); 1385 sshbuf_free(state->outgoing_packet); 1386 state->outgoing_packet = p->payload; 1387 TAILQ_REMOVE(&state->outgoing, p, next); 1388 memset(p, 0, sizeof(*p)); 1389 free(p); 1390 if ((r = ssh_packet_send2_wrapped(ssh)) != 0) 1391 return r; 1392 } 1393 } 1394 return 0; 1395} 1396 1397/* 1398 * Waits until a packet has been received, and returns its type. Note that 1399 * no other data is processed until this returns, so this function should not 1400 * be used during the interactive session. 1401 */ 1402 1403int 1404ssh_packet_read_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1405{ 1406 struct session_state *state = ssh->state; 1407 int len, r, ms_remain = 0; 1408 struct pollfd pfd; 1409 char buf[8192]; 1410 struct timeval start; 1411 struct timespec timespec, *timespecp = NULL; 1412 1413 DBG(debug("packet_read()")); 1414 1415 /* 1416 * Since we are blocking, ensure that all written packets have 1417 * been sent. 1418 */ 1419 if ((r = ssh_packet_write_wait(ssh)) != 0) 1420 goto out; 1421 1422 /* Stay in the loop until we have received a complete packet. */ 1423 for (;;) { 1424 /* Try to read a packet from the buffer. */ 1425 if ((r = ssh_packet_read_poll_seqnr(ssh, typep, seqnr_p)) != 0) 1426 break; 1427 /* If we got a packet, return it. */ 1428 if (*typep != SSH_MSG_NONE) 1429 break; 1430 /* 1431 * Otherwise, wait for some data to arrive, add it to the 1432 * buffer, and try again. 1433 */ 1434 pfd.fd = state->connection_in; 1435 pfd.events = POLLIN; 1436 1437 if (state->packet_timeout_ms > 0) { 1438 ms_remain = state->packet_timeout_ms; 1439 timespecp = ×pec; 1440 } 1441 /* Wait for some data to arrive. */ 1442 for (;;) { 1443 if (state->packet_timeout_ms > 0) { 1444 ms_to_timespec(×pec, ms_remain); 1445 monotime_tv(&start); 1446 } 1447 if ((r = ppoll(&pfd, 1, timespecp, NULL)) >= 0) 1448 break; 1449 if (errno != EAGAIN && errno != EINTR) { 1450 r = SSH_ERR_SYSTEM_ERROR; 1451 goto out; 1452 } 1453 if (state->packet_timeout_ms <= 0) 1454 continue; 1455 ms_subtract_diff(&start, &ms_remain); 1456 if (ms_remain <= 0) { 1457 r = 0; 1458 break; 1459 } 1460 } 1461 if (r == 0) { 1462 r = SSH_ERR_CONN_TIMEOUT; 1463 goto out; 1464 } 1465 /* Read data from the socket. */ 1466 len = read(state->connection_in, buf, sizeof(buf)); 1467 if (len == 0) { 1468 r = SSH_ERR_CONN_CLOSED; 1469 goto out; 1470 } 1471 if (len == -1) { 1472 r = SSH_ERR_SYSTEM_ERROR; 1473 goto out; 1474 } 1475 1476 /* Append it to the buffer. */ 1477 if ((r = ssh_packet_process_incoming(ssh, buf, len)) != 0) 1478 goto out; 1479 } 1480 out: 1481 return r; 1482} 1483 1484int 1485ssh_packet_read(struct ssh *ssh) 1486{ 1487 u_char type; 1488 int r; 1489 1490 if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0) 1491 fatal_fr(r, "read"); 1492 return type; 1493} 1494 1495static int 1496ssh_packet_read_poll2_mux(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1497{ 1498 struct session_state *state = ssh->state; 1499 const u_char *cp; 1500 size_t need; 1501 int r; 1502 1503 if (ssh->kex) 1504 return SSH_ERR_INTERNAL_ERROR; 1505 *typep = SSH_MSG_NONE; 1506 cp = sshbuf_ptr(state->input); 1507 if (state->packlen == 0) { 1508 if (sshbuf_len(state->input) < 4 + 1) 1509 return 0; /* packet is incomplete */ 1510 state->packlen = PEEK_U32(cp); 1511 if (state->packlen < 4 + 1 || 1512 state->packlen > PACKET_MAX_SIZE) 1513 return SSH_ERR_MESSAGE_INCOMPLETE; 1514 } 1515 need = state->packlen + 4; 1516 if (sshbuf_len(state->input) < need) 1517 return 0; /* packet is incomplete */ 1518 sshbuf_reset(state->incoming_packet); 1519 if ((r = sshbuf_put(state->incoming_packet, cp + 4, 1520 state->packlen)) != 0 || 1521 (r = sshbuf_consume(state->input, need)) != 0 || 1522 (r = sshbuf_get_u8(state->incoming_packet, NULL)) != 0 || 1523 (r = sshbuf_get_u8(state->incoming_packet, typep)) != 0) 1524 return r; 1525 if (ssh_packet_log_type(*typep)) 1526 debug3_f("type %u", *typep); 1527 /* sshbuf_dump(state->incoming_packet, stderr); */ 1528 /* reset for next packet */ 1529 state->packlen = 0; 1530 return r; 1531} 1532 1533int 1534ssh_packet_read_poll2(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1535{ 1536 struct session_state *state = ssh->state; 1537 u_int padlen, need; 1538 u_char *cp; 1539 u_int maclen, aadlen = 0, authlen = 0, block_size; 1540 struct sshenc *enc = NULL; 1541 struct sshmac *mac = NULL; 1542 struct sshcomp *comp = NULL; 1543 int r; 1544 1545 if (state->mux) 1546 return ssh_packet_read_poll2_mux(ssh, typep, seqnr_p); 1547 1548 *typep = SSH_MSG_NONE; 1549 1550 if (state->packet_discard) 1551 return 0; 1552 1553 if (state->newkeys[MODE_IN] != NULL) { 1554 enc = &state->newkeys[MODE_IN]->enc; 1555 mac = &state->newkeys[MODE_IN]->mac; 1556 comp = &state->newkeys[MODE_IN]->comp; 1557 /* disable mac for authenticated encryption */ 1558 if ((authlen = cipher_authlen(enc->cipher)) != 0) 1559 mac = NULL; 1560 } 1561 maclen = mac && mac->enabled ? mac->mac_len : 0; 1562 block_size = enc ? enc->block_size : 8; 1563 aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0; 1564 1565 if (aadlen && state->packlen == 0) { 1566 if (cipher_get_length(state->receive_context, 1567 &state->packlen, state->p_read.seqnr, 1568 sshbuf_ptr(state->input), sshbuf_len(state->input)) != 0) 1569 return 0; 1570 if (state->packlen < 1 + 4 || 1571 state->packlen > PACKET_MAX_SIZE) { 1572#ifdef PACKET_DEBUG 1573 sshbuf_dump(state->input, stderr); 1574#endif 1575 logit("Bad packet length %u.", state->packlen); 1576 if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0) 1577 return r; 1578 return SSH_ERR_CONN_CORRUPT; 1579 } 1580 sshbuf_reset(state->incoming_packet); 1581 } else if (state->packlen == 0) { 1582 /* 1583 * check if input size is less than the cipher block size, 1584 * decrypt first block and extract length of incoming packet 1585 */ 1586 if (sshbuf_len(state->input) < block_size) 1587 return 0; 1588 sshbuf_reset(state->incoming_packet); 1589 if ((r = sshbuf_reserve(state->incoming_packet, block_size, 1590 &cp)) != 0) 1591 goto out; 1592 if ((r = cipher_crypt(state->receive_context, 1593 state->p_send.seqnr, cp, sshbuf_ptr(state->input), 1594 block_size, 0, 0)) != 0) 1595 goto out; 1596 state->packlen = PEEK_U32(sshbuf_ptr(state->incoming_packet)); 1597 if (state->packlen < 1 + 4 || 1598 state->packlen > PACKET_MAX_SIZE) { 1599#ifdef PACKET_DEBUG 1600 fprintf(stderr, "input: \n"); 1601 sshbuf_dump(state->input, stderr); 1602 fprintf(stderr, "incoming_packet: \n"); 1603 sshbuf_dump(state->incoming_packet, stderr); 1604#endif 1605 logit("Bad packet length %u.", state->packlen); 1606 return ssh_packet_start_discard(ssh, enc, mac, 0, 1607 PACKET_MAX_SIZE); 1608 } 1609 if ((r = sshbuf_consume(state->input, block_size)) != 0) 1610 goto out; 1611 } 1612 DBG(debug("input: packet len %u", state->packlen+4)); 1613 1614 if (aadlen) { 1615 /* only the payload is encrypted */ 1616 need = state->packlen; 1617 } else { 1618 /* 1619 * the payload size and the payload are encrypted, but we 1620 * have a partial packet of block_size bytes 1621 */ 1622 need = 4 + state->packlen - block_size; 1623 } 1624 DBG(debug("partial packet: block %d, need %d, maclen %d, authlen %d," 1625 " aadlen %d", block_size, need, maclen, authlen, aadlen)); 1626 if (need % block_size != 0) { 1627 logit("padding error: need %d block %d mod %d", 1628 need, block_size, need % block_size); 1629 return ssh_packet_start_discard(ssh, enc, mac, 0, 1630 PACKET_MAX_SIZE - block_size); 1631 } 1632 /* 1633 * check if the entire packet has been received and 1634 * decrypt into incoming_packet: 1635 * 'aadlen' bytes are unencrypted, but authenticated. 1636 * 'need' bytes are encrypted, followed by either 1637 * 'authlen' bytes of authentication tag or 1638 * 'maclen' bytes of message authentication code. 1639 */ 1640 if (sshbuf_len(state->input) < aadlen + need + authlen + maclen) 1641 return 0; /* packet is incomplete */ 1642#ifdef PACKET_DEBUG 1643 fprintf(stderr, "read_poll enc/full: "); 1644 sshbuf_dump(state->input, stderr); 1645#endif 1646 /* EtM: check mac over encrypted input */ 1647 if (mac && mac->enabled && mac->etm) { 1648 if ((r = mac_check(mac, state->p_read.seqnr, 1649 sshbuf_ptr(state->input), aadlen + need, 1650 sshbuf_ptr(state->input) + aadlen + need + authlen, 1651 maclen)) != 0) { 1652 if (r == SSH_ERR_MAC_INVALID) 1653 logit("Corrupted MAC on input."); 1654 goto out; 1655 } 1656 } 1657 if ((r = sshbuf_reserve(state->incoming_packet, aadlen + need, 1658 &cp)) != 0) 1659 goto out; 1660 if ((r = cipher_crypt(state->receive_context, state->p_read.seqnr, cp, 1661 sshbuf_ptr(state->input), need, aadlen, authlen)) != 0) 1662 goto out; 1663 if ((r = sshbuf_consume(state->input, aadlen + need + authlen)) != 0) 1664 goto out; 1665 if (mac && mac->enabled) { 1666 /* Not EtM: check MAC over cleartext */ 1667 if (!mac->etm && (r = mac_check(mac, state->p_read.seqnr, 1668 sshbuf_ptr(state->incoming_packet), 1669 sshbuf_len(state->incoming_packet), 1670 sshbuf_ptr(state->input), maclen)) != 0) { 1671 if (r != SSH_ERR_MAC_INVALID) 1672 goto out; 1673 logit("Corrupted MAC on input."); 1674 if (need + block_size > PACKET_MAX_SIZE) 1675 return SSH_ERR_INTERNAL_ERROR; 1676 return ssh_packet_start_discard(ssh, enc, mac, 1677 sshbuf_len(state->incoming_packet), 1678 PACKET_MAX_SIZE - need - block_size); 1679 } 1680 /* Remove MAC from input buffer */ 1681 DBG(debug("MAC #%d ok", state->p_read.seqnr)); 1682 if ((r = sshbuf_consume(state->input, mac->mac_len)) != 0) 1683 goto out; 1684 } 1685 1686 if (seqnr_p != NULL) 1687 *seqnr_p = state->p_read.seqnr; 1688 if (++state->p_read.seqnr == 0) { 1689 if ((ssh->kex->flags & KEX_INITIAL) != 0) { 1690 ssh_packet_disconnect(ssh, "incoming sequence number " 1691 "wrapped during initial key exchange"); 1692 } 1693 logit("incoming seqnr wraps around"); 1694 } 1695 if (++state->p_read.packets == 0) 1696 if (!(ssh->compat & SSH_BUG_NOREKEY)) 1697 return SSH_ERR_NEED_REKEY; 1698 state->p_read.blocks += (state->packlen + 4) / block_size; 1699 state->p_read.bytes += state->packlen + 4; 1700 1701 /* get padlen */ 1702 padlen = sshbuf_ptr(state->incoming_packet)[4]; 1703 DBG(debug("input: padlen %d", padlen)); 1704 if (padlen < 4) { 1705 if ((r = sshpkt_disconnect(ssh, 1706 "Corrupted padlen %d on input.", padlen)) != 0 || 1707 (r = ssh_packet_write_wait(ssh)) != 0) 1708 return r; 1709 return SSH_ERR_CONN_CORRUPT; 1710 } 1711 1712 /* skip packet size + padlen, discard padding */ 1713 if ((r = sshbuf_consume(state->incoming_packet, 4 + 1)) != 0 || 1714 ((r = sshbuf_consume_end(state->incoming_packet, padlen)) != 0)) 1715 goto out; 1716 1717 DBG(debug("input: len before de-compress %zd", 1718 sshbuf_len(state->incoming_packet))); 1719 if (comp && comp->enabled) { 1720 sshbuf_reset(state->compression_buffer); 1721 if ((r = uncompress_buffer(ssh, state->incoming_packet, 1722 state->compression_buffer)) != 0) 1723 goto out; 1724 sshbuf_reset(state->incoming_packet); 1725 if ((r = sshbuf_putb(state->incoming_packet, 1726 state->compression_buffer)) != 0) 1727 goto out; 1728 DBG(debug("input: len after de-compress %zd", 1729 sshbuf_len(state->incoming_packet))); 1730 } 1731 /* 1732 * get packet type, implies consume. 1733 * return length of payload (without type field) 1734 */ 1735 if ((r = sshbuf_get_u8(state->incoming_packet, typep)) != 0) 1736 goto out; 1737 if (ssh_packet_log_type(*typep)) 1738 debug3("receive packet: type %u", *typep); 1739 if (*typep < SSH2_MSG_MIN) { 1740 if ((r = sshpkt_disconnect(ssh, 1741 "Invalid ssh2 packet type: %d", *typep)) != 0 || 1742 (r = ssh_packet_write_wait(ssh)) != 0) 1743 return r; 1744 return SSH_ERR_PROTOCOL_ERROR; 1745 } 1746 if (state->hook_in != NULL && 1747 (r = state->hook_in(ssh, state->incoming_packet, typep, 1748 state->hook_in_ctx)) != 0) 1749 return r; 1750 if (*typep == SSH2_MSG_USERAUTH_SUCCESS && !state->server_side) 1751 r = ssh_packet_enable_delayed_compress(ssh); 1752 else 1753 r = 0; 1754#ifdef PACKET_DEBUG 1755 fprintf(stderr, "read/plain[%d]:\r\n", *typep); 1756 sshbuf_dump(state->incoming_packet, stderr); 1757#endif 1758 /* reset for next packet */ 1759 state->packlen = 0; 1760 if (*typep == SSH2_MSG_NEWKEYS && ssh->kex->kex_strict) { 1761 debug_f("resetting read seqnr %u", state->p_read.seqnr); 1762 state->p_read.seqnr = 0; 1763 } 1764 1765 if ((r = ssh_packet_check_rekey(ssh)) != 0) 1766 return r; 1767 out: 1768 return r; 1769} 1770 1771int 1772ssh_packet_read_poll_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1773{ 1774 struct session_state *state = ssh->state; 1775 u_int reason, seqnr; 1776 int r; 1777 u_char *msg; 1778 const u_char *d; 1779 size_t len; 1780 1781 for (;;) { 1782 msg = NULL; 1783 r = ssh_packet_read_poll2(ssh, typep, seqnr_p); 1784 if (r != 0) 1785 return r; 1786 if (*typep == 0) { 1787 /* no message ready */ 1788 return 0; 1789 } 1790 state->keep_alive_timeouts = 0; 1791 DBG(debug("received packet type %d", *typep)); 1792 1793 /* Always process disconnect messages */ 1794 if (*typep == SSH2_MSG_DISCONNECT) { 1795 if ((r = sshpkt_get_u32(ssh, &reason)) != 0 || 1796 (r = sshpkt_get_string(ssh, &msg, NULL)) != 0) 1797 return r; 1798 /* Ignore normal client exit notifications */ 1799 do_log2(ssh->state->server_side && 1800 reason == SSH2_DISCONNECT_BY_APPLICATION ? 1801 SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_ERROR, 1802 "Received disconnect from %s port %d:" 1803 "%u: %.400s", ssh_remote_ipaddr(ssh), 1804 ssh_remote_port(ssh), reason, msg); 1805 free(msg); 1806 return SSH_ERR_DISCONNECTED; 1807 } 1808 1809 /* 1810 * Do not implicitly handle any messages here during initial 1811 * KEX when in strict mode. They will be need to be allowed 1812 * explicitly by the KEX dispatch table or they will generate 1813 * protocol errors. 1814 */ 1815 if (ssh->kex != NULL && 1816 (ssh->kex->flags & KEX_INITIAL) && ssh->kex->kex_strict) 1817 return 0; 1818 /* Implicitly handle transport-level messages */ 1819 switch (*typep) { 1820 case SSH2_MSG_IGNORE: 1821 debug3("Received SSH2_MSG_IGNORE"); 1822 break; 1823 case SSH2_MSG_DEBUG: 1824 if ((r = sshpkt_get_u8(ssh, NULL)) != 0 || 1825 (r = sshpkt_get_string(ssh, &msg, NULL)) != 0 || 1826 (r = sshpkt_get_string(ssh, NULL, NULL)) != 0) { 1827 free(msg); 1828 return r; 1829 } 1830 debug("Remote: %.900s", msg); 1831 free(msg); 1832 break; 1833 case SSH2_MSG_UNIMPLEMENTED: 1834 if ((r = sshpkt_get_u32(ssh, &seqnr)) != 0) 1835 return r; 1836 debug("Received SSH2_MSG_UNIMPLEMENTED for %u", 1837 seqnr); 1838 break; 1839 case SSH2_MSG_PING: 1840 if ((r = sshpkt_get_string_direct(ssh, &d, &len)) != 0) 1841 return r; 1842 DBG(debug("Received SSH2_MSG_PING len %zu", len)); 1843 if ((r = sshpkt_start(ssh, SSH2_MSG_PONG)) != 0 || 1844 (r = sshpkt_put_string(ssh, d, len)) != 0 || 1845 (r = sshpkt_send(ssh)) != 0) 1846 return r; 1847 break; 1848 case SSH2_MSG_PONG: 1849 if ((r = sshpkt_get_string_direct(ssh, 1850 NULL, &len)) != 0) 1851 return r; 1852 DBG(debug("Received SSH2_MSG_PONG len %zu", len)); 1853 break; 1854 default: 1855 return 0; 1856 } 1857 } 1858} 1859 1860/* 1861 * Buffers the supplied input data. This is intended to be used together 1862 * with packet_read_poll(). 1863 */ 1864int 1865ssh_packet_process_incoming(struct ssh *ssh, const char *buf, u_int len) 1866{ 1867 struct session_state *state = ssh->state; 1868 int r; 1869 1870 if (state->packet_discard) { 1871 state->keep_alive_timeouts = 0; /* ?? */ 1872 if (len >= state->packet_discard) { 1873 if ((r = ssh_packet_stop_discard(ssh)) != 0) 1874 return r; 1875 } 1876 state->packet_discard -= len; 1877 return 0; 1878 } 1879 if ((r = sshbuf_put(state->input, buf, len)) != 0) 1880 return r; 1881 1882 return 0; 1883} 1884 1885/* Reads and buffers data from the specified fd */ 1886int 1887ssh_packet_process_read(struct ssh *ssh, int fd) 1888{ 1889 struct session_state *state = ssh->state; 1890 int r; 1891 size_t rlen; 1892 1893 if ((r = sshbuf_read(fd, state->input, PACKET_MAX_SIZE, &rlen)) != 0) 1894 return r; 1895 1896 if (state->packet_discard) { 1897 if ((r = sshbuf_consume_end(state->input, rlen)) != 0) 1898 return r; 1899 state->keep_alive_timeouts = 0; /* ?? */ 1900 if (rlen >= state->packet_discard) { 1901 if ((r = ssh_packet_stop_discard(ssh)) != 0) 1902 return r; 1903 } 1904 state->packet_discard -= rlen; 1905 return 0; 1906 } 1907 return 0; 1908} 1909 1910int 1911ssh_packet_remaining(struct ssh *ssh) 1912{ 1913 return sshbuf_len(ssh->state->incoming_packet); 1914} 1915 1916/* 1917 * Sends a diagnostic message from the server to the client. This message 1918 * can be sent at any time (but not while constructing another message). The 1919 * message is printed immediately, but only if the client is being executed 1920 * in verbose mode. These messages are primarily intended to ease debugging 1921 * authentication problems. The length of the formatted message must not 1922 * exceed 1024 bytes. This will automatically call ssh_packet_write_wait. 1923 */ 1924void 1925ssh_packet_send_debug(struct ssh *ssh, const char *fmt,...) 1926{ 1927 char buf[1024]; 1928 va_list args; 1929 int r; 1930 1931 if ((ssh->compat & SSH_BUG_DEBUG)) 1932 return; 1933 1934 va_start(args, fmt); 1935 vsnprintf(buf, sizeof(buf), fmt, args); 1936 va_end(args); 1937 1938 debug3("sending debug message: %s", buf); 1939 1940 if ((r = sshpkt_start(ssh, SSH2_MSG_DEBUG)) != 0 || 1941 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* always display */ 1942 (r = sshpkt_put_cstring(ssh, buf)) != 0 || 1943 (r = sshpkt_put_cstring(ssh, "")) != 0 || 1944 (r = sshpkt_send(ssh)) != 0 || 1945 (r = ssh_packet_write_wait(ssh)) != 0) 1946 fatal_fr(r, "send DEBUG"); 1947} 1948 1949void 1950sshpkt_fmt_connection_id(struct ssh *ssh, char *s, size_t l) 1951{ 1952 snprintf(s, l, "%.200s%s%s port %d", 1953 ssh->log_preamble ? ssh->log_preamble : "", 1954 ssh->log_preamble ? " " : "", 1955 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 1956} 1957 1958/* 1959 * Pretty-print connection-terminating errors and exit. 1960 */ 1961static void 1962sshpkt_vfatal(struct ssh *ssh, int r, const char *fmt, va_list ap) 1963{ 1964 char *tag = NULL, remote_id[512]; 1965 int oerrno = errno; 1966 1967 sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id)); 1968 1969 switch (r) { 1970 case SSH_ERR_CONN_CLOSED: 1971 ssh_packet_clear_keys(ssh); 1972 logdie("Connection closed by %s", remote_id); 1973 case SSH_ERR_CONN_TIMEOUT: 1974 ssh_packet_clear_keys(ssh); 1975 logdie("Connection %s %s timed out", 1976 ssh->state->server_side ? "from" : "to", remote_id); 1977 case SSH_ERR_DISCONNECTED: 1978 ssh_packet_clear_keys(ssh); 1979 logdie("Disconnected from %s", remote_id); 1980 case SSH_ERR_SYSTEM_ERROR: 1981 if (errno == ECONNRESET) { 1982 ssh_packet_clear_keys(ssh); 1983 logdie("Connection reset by %s", remote_id); 1984 } 1985 /* FALLTHROUGH */ 1986 case SSH_ERR_NO_CIPHER_ALG_MATCH: 1987 case SSH_ERR_NO_MAC_ALG_MATCH: 1988 case SSH_ERR_NO_COMPRESS_ALG_MATCH: 1989 case SSH_ERR_NO_KEX_ALG_MATCH: 1990 case SSH_ERR_NO_HOSTKEY_ALG_MATCH: 1991 if (ssh->kex && ssh->kex->failed_choice) { 1992 ssh_packet_clear_keys(ssh); 1993 errno = oerrno; 1994 logdie("Unable to negotiate with %s: %s. " 1995 "Their offer: %s", remote_id, ssh_err(r), 1996 ssh->kex->failed_choice); 1997 } 1998 /* FALLTHROUGH */ 1999 default: 2000 if (vasprintf(&tag, fmt, ap) == -1) { 2001 ssh_packet_clear_keys(ssh); 2002 logdie_f("could not allocate failure message"); 2003 } 2004 ssh_packet_clear_keys(ssh); 2005 errno = oerrno; 2006 logdie_r(r, "%s%sConnection %s %s", 2007 tag != NULL ? tag : "", tag != NULL ? ": " : "", 2008 ssh->state->server_side ? "from" : "to", remote_id); 2009 } 2010} 2011 2012void 2013sshpkt_fatal(struct ssh *ssh, int r, const char *fmt, ...) 2014{ 2015 va_list ap; 2016 2017 va_start(ap, fmt); 2018 sshpkt_vfatal(ssh, r, fmt, ap); 2019 /* NOTREACHED */ 2020 va_end(ap); 2021 logdie_f("should have exited"); 2022} 2023 2024/* 2025 * Logs the error plus constructs and sends a disconnect packet, closes the 2026 * connection, and exits. This function never returns. The error message 2027 * should not contain a newline. The length of the formatted message must 2028 * not exceed 1024 bytes. 2029 */ 2030void 2031ssh_packet_disconnect(struct ssh *ssh, const char *fmt,...) 2032{ 2033 char buf[1024], remote_id[512]; 2034 va_list args; 2035 static int disconnecting = 0; 2036 int r; 2037 2038 if (disconnecting) /* Guard against recursive invocations. */ 2039 fatal("packet_disconnect called recursively."); 2040 disconnecting = 1; 2041 2042 /* 2043 * Format the message. Note that the caller must make sure the 2044 * message is of limited size. 2045 */ 2046 sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id)); 2047 va_start(args, fmt); 2048 vsnprintf(buf, sizeof(buf), fmt, args); 2049 va_end(args); 2050 2051 /* Display the error locally */ 2052 logit("Disconnecting %s: %.100s", remote_id, buf); 2053 2054 /* 2055 * Send the disconnect message to the other side, and wait 2056 * for it to get sent. 2057 */ 2058 if ((r = sshpkt_disconnect(ssh, "%s", buf)) != 0) 2059 sshpkt_fatal(ssh, r, "%s", __func__); 2060 2061 if ((r = ssh_packet_write_wait(ssh)) != 0) 2062 sshpkt_fatal(ssh, r, "%s", __func__); 2063 2064 /* Close the connection. */ 2065 ssh_packet_close(ssh); 2066 cleanup_exit(255); 2067} 2068 2069/* 2070 * Checks if there is any buffered output, and tries to write some of 2071 * the output. 2072 */ 2073int 2074ssh_packet_write_poll(struct ssh *ssh) 2075{ 2076 struct session_state *state = ssh->state; 2077 int len = sshbuf_len(state->output); 2078 int r; 2079 2080 if (len > 0) { 2081 len = write(state->connection_out, 2082 sshbuf_ptr(state->output), len); 2083 if (len == -1) { 2084 if (errno == EINTR || errno == EAGAIN) 2085 return 0; 2086 return SSH_ERR_SYSTEM_ERROR; 2087 } 2088 if (len == 0) 2089 return SSH_ERR_CONN_CLOSED; 2090 if ((r = sshbuf_consume(state->output, len)) != 0) 2091 return r; 2092 } 2093 return 0; 2094} 2095 2096/* 2097 * Calls packet_write_poll repeatedly until all pending output data has been 2098 * written. 2099 */ 2100int 2101ssh_packet_write_wait(struct ssh *ssh) 2102{ 2103 int ret, r, ms_remain = 0; 2104 struct timeval start; 2105 struct timespec timespec, *timespecp = NULL; 2106 struct session_state *state = ssh->state; 2107 struct pollfd pfd; 2108 2109 if ((r = ssh_packet_write_poll(ssh)) != 0) 2110 return r; 2111 while (ssh_packet_have_data_to_write(ssh)) { 2112 pfd.fd = state->connection_out; 2113 pfd.events = POLLOUT; 2114 2115 if (state->packet_timeout_ms > 0) { 2116 ms_remain = state->packet_timeout_ms; 2117 timespecp = ×pec; 2118 } 2119 for (;;) { 2120 if (state->packet_timeout_ms > 0) { 2121 ms_to_timespec(×pec, ms_remain); 2122 monotime_tv(&start); 2123 } 2124 if ((ret = ppoll(&pfd, 1, timespecp, NULL)) >= 0) 2125 break; 2126 if (errno != EAGAIN && errno != EINTR) 2127 break; 2128 if (state->packet_timeout_ms <= 0) 2129 continue; 2130 ms_subtract_diff(&start, &ms_remain); 2131 if (ms_remain <= 0) { 2132 ret = 0; 2133 break; 2134 } 2135 } 2136 if (ret == 0) 2137 return SSH_ERR_CONN_TIMEOUT; 2138 if ((r = ssh_packet_write_poll(ssh)) != 0) 2139 return r; 2140 } 2141 return 0; 2142} 2143 2144/* Returns true if there is buffered data to write to the connection. */ 2145 2146int 2147ssh_packet_have_data_to_write(struct ssh *ssh) 2148{ 2149 return sshbuf_len(ssh->state->output) != 0; 2150} 2151 2152/* Returns true if there is not too much data to write to the connection. */ 2153 2154int 2155ssh_packet_not_very_much_data_to_write(struct ssh *ssh) 2156{ 2157 if (ssh->state->interactive_mode) 2158 return sshbuf_len(ssh->state->output) < 16384; 2159 else 2160 return sshbuf_len(ssh->state->output) < 128 * 1024; 2161} 2162 2163/* 2164 * returns true when there are at most a few keystrokes of data to write 2165 * and the connection is in interactive mode. 2166 */ 2167 2168int 2169ssh_packet_interactive_data_to_write(struct ssh *ssh) 2170{ 2171 return ssh->state->interactive_mode && 2172 sshbuf_len(ssh->state->output) < 256; 2173} 2174 2175void 2176ssh_packet_set_tos(struct ssh *ssh, int tos) 2177{ 2178 if (!ssh_packet_connection_is_on_socket(ssh) || tos == INT_MAX) 2179 return; 2180 set_sock_tos(ssh->state->connection_in, tos); 2181} 2182 2183/* Informs that the current session is interactive. Sets IP flags for that. */ 2184 2185void 2186ssh_packet_set_interactive(struct ssh *ssh, int interactive, int qos_interactive, int qos_bulk) 2187{ 2188 struct session_state *state = ssh->state; 2189 2190 if (state->set_interactive_called) 2191 return; 2192 state->set_interactive_called = 1; 2193 2194 /* Record that we are in interactive mode. */ 2195 state->interactive_mode = interactive; 2196 2197 /* Only set socket options if using a socket. */ 2198 if (!ssh_packet_connection_is_on_socket(ssh)) 2199 return; 2200 set_nodelay(state->connection_in); 2201 ssh_packet_set_tos(ssh, interactive ? qos_interactive : qos_bulk); 2202} 2203 2204/* Returns true if the current connection is interactive. */ 2205 2206int 2207ssh_packet_is_interactive(struct ssh *ssh) 2208{ 2209 return ssh->state->interactive_mode; 2210} 2211 2212int 2213ssh_packet_set_maxsize(struct ssh *ssh, u_int s) 2214{ 2215 struct session_state *state = ssh->state; 2216 2217 if (state->set_maxsize_called) { 2218 logit_f("called twice: old %d new %d", 2219 state->max_packet_size, s); 2220 return -1; 2221 } 2222 if (s < 4 * 1024 || s > 1024 * 1024) { 2223 logit_f("bad size %d", s); 2224 return -1; 2225 } 2226 state->set_maxsize_called = 1; 2227 debug_f("setting to %d", s); 2228 state->max_packet_size = s; 2229 return s; 2230} 2231 2232int 2233ssh_packet_inc_alive_timeouts(struct ssh *ssh) 2234{ 2235 return ++ssh->state->keep_alive_timeouts; 2236} 2237 2238void 2239ssh_packet_set_alive_timeouts(struct ssh *ssh, int ka) 2240{ 2241 ssh->state->keep_alive_timeouts = ka; 2242} 2243 2244u_int 2245ssh_packet_get_maxsize(struct ssh *ssh) 2246{ 2247 return ssh->state->max_packet_size; 2248} 2249 2250void 2251ssh_packet_set_rekey_limits(struct ssh *ssh, u_int64_t bytes, u_int32_t seconds) 2252{ 2253 debug3("rekey after %llu bytes, %u seconds", (unsigned long long)bytes, 2254 (unsigned int)seconds); 2255 ssh->state->rekey_limit = bytes; 2256 ssh->state->rekey_interval = seconds; 2257} 2258 2259time_t 2260ssh_packet_get_rekey_timeout(struct ssh *ssh) 2261{ 2262 time_t seconds; 2263 2264 seconds = ssh->state->rekey_time + ssh->state->rekey_interval - 2265 monotime(); 2266 return (seconds <= 0 ? 1 : seconds); 2267} 2268 2269void 2270ssh_packet_set_server(struct ssh *ssh) 2271{ 2272 ssh->state->server_side = 1; 2273 ssh->kex->server = 1; /* XXX unify? */ 2274} 2275 2276void 2277ssh_packet_set_authenticated(struct ssh *ssh) 2278{ 2279 ssh->state->after_authentication = 1; 2280} 2281 2282void * 2283ssh_packet_get_input(struct ssh *ssh) 2284{ 2285 return (void *)ssh->state->input; 2286} 2287 2288void * 2289ssh_packet_get_output(struct ssh *ssh) 2290{ 2291 return (void *)ssh->state->output; 2292} 2293 2294/* Reset after_authentication and reset compression in post-auth privsep */ 2295static int 2296ssh_packet_set_postauth(struct ssh *ssh) 2297{ 2298 int r; 2299 2300 debug_f("called"); 2301 /* This was set in net child, but is not visible in user child */ 2302 ssh->state->after_authentication = 1; 2303 ssh->state->rekeying = 0; 2304 if ((r = ssh_packet_enable_delayed_compress(ssh)) != 0) 2305 return r; 2306 return 0; 2307} 2308 2309/* Packet state (de-)serialization for privsep */ 2310 2311/* turn kex into a blob for packet state serialization */ 2312static int 2313kex_to_blob(struct sshbuf *m, struct kex *kex) 2314{ 2315 int r; 2316 2317 if ((r = sshbuf_put_u32(m, kex->we_need)) != 0 || 2318 (r = sshbuf_put_cstring(m, kex->hostkey_alg)) != 0 || 2319 (r = sshbuf_put_u32(m, kex->hostkey_type)) != 0 || 2320 (r = sshbuf_put_u32(m, kex->hostkey_nid)) != 0 || 2321 (r = sshbuf_put_u32(m, kex->kex_type)) != 0 || 2322 (r = sshbuf_put_u32(m, kex->kex_strict)) != 0 || 2323 (r = sshbuf_put_stringb(m, kex->my)) != 0 || 2324 (r = sshbuf_put_stringb(m, kex->peer)) != 0 || 2325 (r = sshbuf_put_stringb(m, kex->client_version)) != 0 || 2326 (r = sshbuf_put_stringb(m, kex->server_version)) != 0 || 2327 (r = sshbuf_put_stringb(m, kex->session_id)) != 0 || 2328 (r = sshbuf_put_u32(m, kex->flags)) != 0) 2329 return r; 2330 return 0; 2331} 2332 2333/* turn key exchange results into a blob for packet state serialization */ 2334static int 2335newkeys_to_blob(struct sshbuf *m, struct ssh *ssh, int mode) 2336{ 2337 struct sshbuf *b; 2338 struct sshcipher_ctx *cc; 2339 struct sshcomp *comp; 2340 struct sshenc *enc; 2341 struct sshmac *mac; 2342 struct newkeys *newkey; 2343 int r; 2344 2345 if ((newkey = ssh->state->newkeys[mode]) == NULL) 2346 return SSH_ERR_INTERNAL_ERROR; 2347 enc = &newkey->enc; 2348 mac = &newkey->mac; 2349 comp = &newkey->comp; 2350 cc = (mode == MODE_OUT) ? ssh->state->send_context : 2351 ssh->state->receive_context; 2352 if ((r = cipher_get_keyiv(cc, enc->iv, enc->iv_len)) != 0) 2353 return r; 2354 if ((b = sshbuf_new()) == NULL) 2355 return SSH_ERR_ALLOC_FAIL; 2356 if ((r = sshbuf_put_cstring(b, enc->name)) != 0 || 2357 (r = sshbuf_put_u32(b, enc->enabled)) != 0 || 2358 (r = sshbuf_put_u32(b, enc->block_size)) != 0 || 2359 (r = sshbuf_put_string(b, enc->key, enc->key_len)) != 0 || 2360 (r = sshbuf_put_string(b, enc->iv, enc->iv_len)) != 0) 2361 goto out; 2362 if (cipher_authlen(enc->cipher) == 0) { 2363 if ((r = sshbuf_put_cstring(b, mac->name)) != 0 || 2364 (r = sshbuf_put_u32(b, mac->enabled)) != 0 || 2365 (r = sshbuf_put_string(b, mac->key, mac->key_len)) != 0) 2366 goto out; 2367 } 2368 if ((r = sshbuf_put_u32(b, comp->type)) != 0 || 2369 (r = sshbuf_put_cstring(b, comp->name)) != 0) 2370 goto out; 2371 r = sshbuf_put_stringb(m, b); 2372 out: 2373 sshbuf_free(b); 2374 return r; 2375} 2376 2377/* serialize packet state into a blob */ 2378int 2379ssh_packet_get_state(struct ssh *ssh, struct sshbuf *m) 2380{ 2381 struct session_state *state = ssh->state; 2382 int r; 2383 2384 if ((r = kex_to_blob(m, ssh->kex)) != 0 || 2385 (r = newkeys_to_blob(m, ssh, MODE_OUT)) != 0 || 2386 (r = newkeys_to_blob(m, ssh, MODE_IN)) != 0 || 2387 (r = sshbuf_put_u64(m, state->rekey_limit)) != 0 || 2388 (r = sshbuf_put_u32(m, state->rekey_interval)) != 0 || 2389 (r = sshbuf_put_u32(m, state->p_send.seqnr)) != 0 || 2390 (r = sshbuf_put_u64(m, state->p_send.blocks)) != 0 || 2391 (r = sshbuf_put_u32(m, state->p_send.packets)) != 0 || 2392 (r = sshbuf_put_u64(m, state->p_send.bytes)) != 0 || 2393 (r = sshbuf_put_u32(m, state->p_read.seqnr)) != 0 || 2394 (r = sshbuf_put_u64(m, state->p_read.blocks)) != 0 || 2395 (r = sshbuf_put_u32(m, state->p_read.packets)) != 0 || 2396 (r = sshbuf_put_u64(m, state->p_read.bytes)) != 0 || 2397 (r = sshbuf_put_stringb(m, state->input)) != 0 || 2398 (r = sshbuf_put_stringb(m, state->output)) != 0) 2399 return r; 2400 2401 return 0; 2402} 2403 2404/* restore key exchange results from blob for packet state de-serialization */ 2405static int 2406newkeys_from_blob(struct sshbuf *m, struct ssh *ssh, int mode) 2407{ 2408 struct sshbuf *b = NULL; 2409 struct sshcomp *comp; 2410 struct sshenc *enc; 2411 struct sshmac *mac; 2412 struct newkeys *newkey = NULL; 2413 size_t keylen, ivlen, maclen; 2414 int r; 2415 2416 if ((newkey = calloc(1, sizeof(*newkey))) == NULL) { 2417 r = SSH_ERR_ALLOC_FAIL; 2418 goto out; 2419 } 2420 if ((r = sshbuf_froms(m, &b)) != 0) 2421 goto out; 2422#ifdef DEBUG_PK 2423 sshbuf_dump(b, stderr); 2424#endif 2425 enc = &newkey->enc; 2426 mac = &newkey->mac; 2427 comp = &newkey->comp; 2428 2429 if ((r = sshbuf_get_cstring(b, &enc->name, NULL)) != 0 || 2430 (r = sshbuf_get_u32(b, (u_int *)&enc->enabled)) != 0 || 2431 (r = sshbuf_get_u32(b, &enc->block_size)) != 0 || 2432 (r = sshbuf_get_string(b, &enc->key, &keylen)) != 0 || 2433 (r = sshbuf_get_string(b, &enc->iv, &ivlen)) != 0) 2434 goto out; 2435 if ((enc->cipher = cipher_by_name(enc->name)) == NULL) { 2436 r = SSH_ERR_INVALID_FORMAT; 2437 goto out; 2438 } 2439 if (cipher_authlen(enc->cipher) == 0) { 2440 if ((r = sshbuf_get_cstring(b, &mac->name, NULL)) != 0) 2441 goto out; 2442 if ((r = mac_setup(mac, mac->name)) != 0) 2443 goto out; 2444 if ((r = sshbuf_get_u32(b, (u_int *)&mac->enabled)) != 0 || 2445 (r = sshbuf_get_string(b, &mac->key, &maclen)) != 0) 2446 goto out; 2447 if (maclen > mac->key_len) { 2448 r = SSH_ERR_INVALID_FORMAT; 2449 goto out; 2450 } 2451 mac->key_len = maclen; 2452 } 2453 if ((r = sshbuf_get_u32(b, &comp->type)) != 0 || 2454 (r = sshbuf_get_cstring(b, &comp->name, NULL)) != 0) 2455 goto out; 2456 if (sshbuf_len(b) != 0) { 2457 r = SSH_ERR_INVALID_FORMAT; 2458 goto out; 2459 } 2460 enc->key_len = keylen; 2461 enc->iv_len = ivlen; 2462 ssh->kex->newkeys[mode] = newkey; 2463 newkey = NULL; 2464 r = 0; 2465 out: 2466 free(newkey); 2467 sshbuf_free(b); 2468 return r; 2469} 2470 2471/* restore kex from blob for packet state de-serialization */ 2472static int 2473kex_from_blob(struct sshbuf *m, struct kex **kexp) 2474{ 2475 struct kex *kex; 2476 int r; 2477 2478 if ((kex = kex_new()) == NULL) 2479 return SSH_ERR_ALLOC_FAIL; 2480 if ((r = sshbuf_get_u32(m, &kex->we_need)) != 0 || 2481 (r = sshbuf_get_cstring(m, &kex->hostkey_alg, NULL)) != 0 || 2482 (r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_type)) != 0 || 2483 (r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_nid)) != 0 || 2484 (r = sshbuf_get_u32(m, &kex->kex_type)) != 0 || 2485 (r = sshbuf_get_u32(m, &kex->kex_strict)) != 0 || 2486 (r = sshbuf_get_stringb(m, kex->my)) != 0 || 2487 (r = sshbuf_get_stringb(m, kex->peer)) != 0 || 2488 (r = sshbuf_get_stringb(m, kex->client_version)) != 0 || 2489 (r = sshbuf_get_stringb(m, kex->server_version)) != 0 || 2490 (r = sshbuf_get_stringb(m, kex->session_id)) != 0 || 2491 (r = sshbuf_get_u32(m, &kex->flags)) != 0) 2492 goto out; 2493 kex->server = 1; 2494 kex->done = 1; 2495 r = 0; 2496 out: 2497 if (r != 0 || kexp == NULL) { 2498 kex_free(kex); 2499 if (kexp != NULL) 2500 *kexp = NULL; 2501 } else { 2502 kex_free(*kexp); 2503 *kexp = kex; 2504 } 2505 return r; 2506} 2507 2508/* 2509 * Restore packet state from content of blob 'm' (de-serialization). 2510 * Note that 'm' will be partially consumed on parsing or any other errors. 2511 */ 2512int 2513ssh_packet_set_state(struct ssh *ssh, struct sshbuf *m) 2514{ 2515 struct session_state *state = ssh->state; 2516 const u_char *input, *output; 2517 size_t ilen, olen; 2518 int r; 2519 2520 if ((r = kex_from_blob(m, &ssh->kex)) != 0 || 2521 (r = newkeys_from_blob(m, ssh, MODE_OUT)) != 0 || 2522 (r = newkeys_from_blob(m, ssh, MODE_IN)) != 0 || 2523 (r = sshbuf_get_u64(m, &state->rekey_limit)) != 0 || 2524 (r = sshbuf_get_u32(m, &state->rekey_interval)) != 0 || 2525 (r = sshbuf_get_u32(m, &state->p_send.seqnr)) != 0 || 2526 (r = sshbuf_get_u64(m, &state->p_send.blocks)) != 0 || 2527 (r = sshbuf_get_u32(m, &state->p_send.packets)) != 0 || 2528 (r = sshbuf_get_u64(m, &state->p_send.bytes)) != 0 || 2529 (r = sshbuf_get_u32(m, &state->p_read.seqnr)) != 0 || 2530 (r = sshbuf_get_u64(m, &state->p_read.blocks)) != 0 || 2531 (r = sshbuf_get_u32(m, &state->p_read.packets)) != 0 || 2532 (r = sshbuf_get_u64(m, &state->p_read.bytes)) != 0) 2533 return r; 2534 /* 2535 * We set the time here so that in post-auth privsep child we 2536 * count from the completion of the authentication. 2537 */ 2538 state->rekey_time = monotime(); 2539 /* XXX ssh_set_newkeys overrides p_read.packets? XXX */ 2540 if ((r = ssh_set_newkeys(ssh, MODE_IN)) != 0 || 2541 (r = ssh_set_newkeys(ssh, MODE_OUT)) != 0) 2542 return r; 2543 2544 if ((r = ssh_packet_set_postauth(ssh)) != 0) 2545 return r; 2546 2547 sshbuf_reset(state->input); 2548 sshbuf_reset(state->output); 2549 if ((r = sshbuf_get_string_direct(m, &input, &ilen)) != 0 || 2550 (r = sshbuf_get_string_direct(m, &output, &olen)) != 0 || 2551 (r = sshbuf_put(state->input, input, ilen)) != 0 || 2552 (r = sshbuf_put(state->output, output, olen)) != 0) 2553 return r; 2554 2555 if (sshbuf_len(m)) 2556 return SSH_ERR_INVALID_FORMAT; 2557 debug3_f("done"); 2558 return 0; 2559} 2560 2561/* NEW API */ 2562 2563/* put data to the outgoing packet */ 2564 2565int 2566sshpkt_put(struct ssh *ssh, const void *v, size_t len) 2567{ 2568 return sshbuf_put(ssh->state->outgoing_packet, v, len); 2569} 2570 2571int 2572sshpkt_putb(struct ssh *ssh, const struct sshbuf *b) 2573{ 2574 return sshbuf_putb(ssh->state->outgoing_packet, b); 2575} 2576 2577int 2578sshpkt_put_u8(struct ssh *ssh, u_char val) 2579{ 2580 return sshbuf_put_u8(ssh->state->outgoing_packet, val); 2581} 2582 2583int 2584sshpkt_put_u32(struct ssh *ssh, u_int32_t val) 2585{ 2586 return sshbuf_put_u32(ssh->state->outgoing_packet, val); 2587} 2588 2589int 2590sshpkt_put_u64(struct ssh *ssh, u_int64_t val) 2591{ 2592 return sshbuf_put_u64(ssh->state->outgoing_packet, val); 2593} 2594 2595int 2596sshpkt_put_string(struct ssh *ssh, const void *v, size_t len) 2597{ 2598 return sshbuf_put_string(ssh->state->outgoing_packet, v, len); 2599} 2600 2601int 2602sshpkt_put_cstring(struct ssh *ssh, const void *v) 2603{ 2604 return sshbuf_put_cstring(ssh->state->outgoing_packet, v); 2605} 2606 2607int 2608sshpkt_put_stringb(struct ssh *ssh, const struct sshbuf *v) 2609{ 2610 return sshbuf_put_stringb(ssh->state->outgoing_packet, v); 2611} 2612 2613#ifdef WITH_OPENSSL 2614int 2615sshpkt_put_ec(struct ssh *ssh, const EC_POINT *v, const EC_GROUP *g) 2616{ 2617 return sshbuf_put_ec(ssh->state->outgoing_packet, v, g); 2618} 2619 2620 2621int 2622sshpkt_put_bignum2(struct ssh *ssh, const BIGNUM *v) 2623{ 2624 return sshbuf_put_bignum2(ssh->state->outgoing_packet, v); 2625} 2626#endif /* WITH_OPENSSL */ 2627 2628/* fetch data from the incoming packet */ 2629 2630int 2631sshpkt_get(struct ssh *ssh, void *valp, size_t len) 2632{ 2633 return sshbuf_get(ssh->state->incoming_packet, valp, len); 2634} 2635 2636int 2637sshpkt_get_u8(struct ssh *ssh, u_char *valp) 2638{ 2639 return sshbuf_get_u8(ssh->state->incoming_packet, valp); 2640} 2641 2642int 2643sshpkt_get_u32(struct ssh *ssh, u_int32_t *valp) 2644{ 2645 return sshbuf_get_u32(ssh->state->incoming_packet, valp); 2646} 2647 2648int 2649sshpkt_get_u64(struct ssh *ssh, u_int64_t *valp) 2650{ 2651 return sshbuf_get_u64(ssh->state->incoming_packet, valp); 2652} 2653 2654int 2655sshpkt_get_string(struct ssh *ssh, u_char **valp, size_t *lenp) 2656{ 2657 return sshbuf_get_string(ssh->state->incoming_packet, valp, lenp); 2658} 2659 2660int 2661sshpkt_get_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp) 2662{ 2663 return sshbuf_get_string_direct(ssh->state->incoming_packet, valp, lenp); 2664} 2665 2666int 2667sshpkt_peek_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp) 2668{ 2669 return sshbuf_peek_string_direct(ssh->state->incoming_packet, valp, lenp); 2670} 2671 2672int 2673sshpkt_get_cstring(struct ssh *ssh, char **valp, size_t *lenp) 2674{ 2675 return sshbuf_get_cstring(ssh->state->incoming_packet, valp, lenp); 2676} 2677 2678int 2679sshpkt_getb_froms(struct ssh *ssh, struct sshbuf **valp) 2680{ 2681 return sshbuf_froms(ssh->state->incoming_packet, valp); 2682} 2683 2684#ifdef WITH_OPENSSL 2685int 2686sshpkt_get_ec(struct ssh *ssh, EC_POINT *v, const EC_GROUP *g) 2687{ 2688 return sshbuf_get_ec(ssh->state->incoming_packet, v, g); 2689} 2690 2691int 2692sshpkt_get_bignum2(struct ssh *ssh, BIGNUM **valp) 2693{ 2694 return sshbuf_get_bignum2(ssh->state->incoming_packet, valp); 2695} 2696#endif /* WITH_OPENSSL */ 2697 2698int 2699sshpkt_get_end(struct ssh *ssh) 2700{ 2701 if (sshbuf_len(ssh->state->incoming_packet) > 0) 2702 return SSH_ERR_UNEXPECTED_TRAILING_DATA; 2703 return 0; 2704} 2705 2706const u_char * 2707sshpkt_ptr(struct ssh *ssh, size_t *lenp) 2708{ 2709 if (lenp != NULL) 2710 *lenp = sshbuf_len(ssh->state->incoming_packet); 2711 return sshbuf_ptr(ssh->state->incoming_packet); 2712} 2713 2714/* start a new packet */ 2715 2716int 2717sshpkt_start(struct ssh *ssh, u_char type) 2718{ 2719 u_char buf[6]; /* u32 packet length, u8 pad len, u8 type */ 2720 2721 DBG(debug("packet_start[%d]", type)); 2722 memset(buf, 0, sizeof(buf)); 2723 buf[sizeof(buf) - 1] = type; 2724 sshbuf_reset(ssh->state->outgoing_packet); 2725 return sshbuf_put(ssh->state->outgoing_packet, buf, sizeof(buf)); 2726} 2727 2728static int 2729ssh_packet_send_mux(struct ssh *ssh) 2730{ 2731 struct session_state *state = ssh->state; 2732 u_char type, *cp; 2733 size_t len; 2734 int r; 2735 2736 if (ssh->kex) 2737 return SSH_ERR_INTERNAL_ERROR; 2738 len = sshbuf_len(state->outgoing_packet); 2739 if (len < 6) 2740 return SSH_ERR_INTERNAL_ERROR; 2741 cp = sshbuf_mutable_ptr(state->outgoing_packet); 2742 type = cp[5]; 2743 if (ssh_packet_log_type(type)) 2744 debug3_f("type %u", type); 2745 /* drop everything, but the connection protocol */ 2746 if (type >= SSH2_MSG_CONNECTION_MIN && 2747 type <= SSH2_MSG_CONNECTION_MAX) { 2748 POKE_U32(cp, len - 4); 2749 if ((r = sshbuf_putb(state->output, 2750 state->outgoing_packet)) != 0) 2751 return r; 2752 /* sshbuf_dump(state->output, stderr); */ 2753 } 2754 sshbuf_reset(state->outgoing_packet); 2755 return 0; 2756} 2757 2758/* 2759 * 9.2. Ignored Data Message 2760 * 2761 * byte SSH_MSG_IGNORE 2762 * string data 2763 * 2764 * All implementations MUST understand (and ignore) this message at any 2765 * time (after receiving the protocol version). No implementation is 2766 * required to send them. This message can be used as an additional 2767 * protection measure against advanced traffic analysis techniques. 2768 */ 2769int 2770sshpkt_msg_ignore(struct ssh *ssh, u_int nbytes) 2771{ 2772 u_int32_t rnd = 0; 2773 int r; 2774 u_int i; 2775 2776 if ((r = sshpkt_start(ssh, SSH2_MSG_IGNORE)) != 0 || 2777 (r = sshpkt_put_u32(ssh, nbytes)) != 0) 2778 return r; 2779 for (i = 0; i < nbytes; i++) { 2780 if (i % 4 == 0) 2781 rnd = arc4random(); 2782 if ((r = sshpkt_put_u8(ssh, (u_char)rnd & 0xff)) != 0) 2783 return r; 2784 rnd >>= 8; 2785 } 2786 return 0; 2787} 2788 2789/* send it */ 2790 2791int 2792sshpkt_send(struct ssh *ssh) 2793{ 2794 if (ssh->state && ssh->state->mux) 2795 return ssh_packet_send_mux(ssh); 2796 return ssh_packet_send2(ssh); 2797} 2798 2799int 2800sshpkt_disconnect(struct ssh *ssh, const char *fmt,...) 2801{ 2802 char buf[1024]; 2803 va_list args; 2804 int r; 2805 2806 va_start(args, fmt); 2807 vsnprintf(buf, sizeof(buf), fmt, args); 2808 va_end(args); 2809 2810 debug2_f("sending SSH2_MSG_DISCONNECT: %s", buf); 2811 if ((r = sshpkt_start(ssh, SSH2_MSG_DISCONNECT)) != 0 || 2812 (r = sshpkt_put_u32(ssh, SSH2_DISCONNECT_PROTOCOL_ERROR)) != 0 || 2813 (r = sshpkt_put_cstring(ssh, buf)) != 0 || 2814 (r = sshpkt_put_cstring(ssh, "")) != 0 || 2815 (r = sshpkt_send(ssh)) != 0) 2816 return r; 2817 return 0; 2818} 2819 2820/* roundup current message to pad bytes */ 2821int 2822sshpkt_add_padding(struct ssh *ssh, u_char pad) 2823{ 2824 ssh->state->extra_pad = pad; 2825 return 0; 2826} 2827