1 /* $OpenBSD: packet.c,v 1.264 2017/09/12 06:32:07 djm Exp $ */ 2 /* 3 * Author: Tatu Ylonen <ylo@cs.hut.fi> 4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 5 * All rights reserved 6 * This file contains code implementing the packet protocol and communication 7 * with the other side. This same code is used both on client and server side. 8 * 9 * As far as I am concerned, the code I have written for this software 10 * can be used freely for any purpose. Any derived versions of this 11 * software must be clearly marked as such, and if the derived work is 12 * incompatible with the protocol description in the RFC file, it must be 13 * called by a name other than "ssh" or "Secure Shell". 14 * 15 * 16 * SSH2 packet format added by Markus Friedl. 17 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. 18 * 19 * Redistribution and use in source and binary forms, with or without 20 * modification, are permitted provided that the following conditions 21 * are met: 22 * 1. Redistributions of source code must retain the above copyright 23 * notice, this list of conditions and the following disclaimer. 24 * 2. Redistributions in binary form must reproduce the above copyright 25 * notice, this list of conditions and the following disclaimer in the 26 * documentation and/or other materials provided with the distribution. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 29 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 30 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 31 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 32 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 33 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 34 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 35 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 36 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 37 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 38 */ 39 40 #include "includes.h" 41 42 #include <sys/types.h> 43 #include "openbsd-compat/sys-queue.h" 44 #include <sys/socket.h> 45 #ifdef HAVE_SYS_TIME_H 46 # include <sys/time.h> 47 #endif 48 49 #include <netinet/in.h> 50 #include <netinet/ip.h> 51 #include <arpa/inet.h> 52 53 #include <errno.h> 54 #include <netdb.h> 55 #include <stdarg.h> 56 #include <stdio.h> 57 #include <stdlib.h> 58 #include <string.h> 59 #include <unistd.h> 60 #include <limits.h> 61 #include <signal.h> 62 #include <time.h> 63 64 #include <zlib.h> 65 66 #include "buffer.h" /* typedefs XXX */ 67 #include "key.h" /* typedefs XXX */ 68 69 #include "xmalloc.h" 70 #include "crc32.h" 71 #include "compat.h" 72 #include "ssh2.h" 73 #include "cipher.h" 74 #include "sshkey.h" 75 #include "kex.h" 76 #include "digest.h" 77 #include "mac.h" 78 #include "log.h" 79 #include "canohost.h" 80 #include "misc.h" 81 #include "channels.h" 82 #include "ssh.h" 83 #include "packet.h" 84 #include "ssherr.h" 85 #include "sshbuf.h" 86 87 #ifdef PACKET_DEBUG 88 #define DBG(x) x 89 #else 90 #define DBG(x) 91 #endif 92 93 #define PACKET_MAX_SIZE (256 * 1024) 94 95 struct packet_state { 96 u_int32_t seqnr; 97 u_int32_t packets; 98 u_int64_t blocks; 99 u_int64_t bytes; 100 }; 101 102 struct packet { 103 TAILQ_ENTRY(packet) next; 104 u_char type; 105 struct sshbuf *payload; 106 }; 107 108 struct session_state { 109 /* 110 * This variable contains the file descriptors used for 111 * communicating with the other side. connection_in is used for 112 * reading; connection_out for writing. These can be the same 113 * descriptor, in which case it is assumed to be a socket. 114 */ 115 int connection_in; 116 int connection_out; 117 118 /* Protocol flags for the remote side. */ 119 u_int remote_protocol_flags; 120 121 /* Encryption context for receiving data. Only used for decryption. */ 122 struct sshcipher_ctx *receive_context; 123 124 /* Encryption context for sending data. Only used for encryption. */ 125 struct sshcipher_ctx *send_context; 126 127 /* Buffer for raw input data from the socket. */ 128 struct sshbuf *input; 129 130 /* Buffer for raw output data going to the socket. */ 131 struct sshbuf *output; 132 133 /* Buffer for the partial outgoing packet being constructed. */ 134 struct sshbuf *outgoing_packet; 135 136 /* Buffer for the incoming packet currently being processed. */ 137 struct sshbuf *incoming_packet; 138 139 /* Scratch buffer for packet compression/decompression. */ 140 struct sshbuf *compression_buffer; 141 142 /* Incoming/outgoing compression dictionaries */ 143 z_stream compression_in_stream; 144 z_stream compression_out_stream; 145 int compression_in_started; 146 int compression_out_started; 147 int compression_in_failures; 148 int compression_out_failures; 149 150 /* 151 * Flag indicating whether packet compression/decompression is 152 * enabled. 153 */ 154 int packet_compression; 155 156 /* default maximum packet size */ 157 u_int max_packet_size; 158 159 /* Flag indicating whether this module has been initialized. */ 160 int initialized; 161 162 /* Set to true if the connection is interactive. */ 163 int interactive_mode; 164 165 /* Set to true if we are the server side. */ 166 int server_side; 167 168 /* Set to true if we are authenticated. */ 169 int after_authentication; 170 171 int keep_alive_timeouts; 172 173 /* The maximum time that we will wait to send or receive a packet */ 174 int packet_timeout_ms; 175 176 /* Session key information for Encryption and MAC */ 177 struct newkeys *newkeys[MODE_MAX]; 178 struct packet_state p_read, p_send; 179 180 /* Volume-based rekeying */ 181 u_int64_t max_blocks_in, max_blocks_out, rekey_limit; 182 183 /* Time-based rekeying */ 184 u_int32_t rekey_interval; /* how often in seconds */ 185 time_t rekey_time; /* time of last rekeying */ 186 187 /* roundup current message to extra_pad bytes */ 188 u_char extra_pad; 189 190 /* XXX discard incoming data after MAC error */ 191 u_int packet_discard; 192 size_t packet_discard_mac_already; 193 struct sshmac *packet_discard_mac; 194 195 /* Used in packet_read_poll2() */ 196 u_int packlen; 197 198 /* Used in packet_send2 */ 199 int rekeying; 200 201 /* Used in ssh_packet_send_mux() */ 202 int mux; 203 204 /* Used in packet_set_interactive */ 205 int set_interactive_called; 206 207 /* Used in packet_set_maxsize */ 208 int set_maxsize_called; 209 210 /* One-off warning about weak ciphers */ 211 int cipher_warning_done; 212 213 /* Hook for fuzzing inbound packets */ 214 ssh_packet_hook_fn *hook_in; 215 void *hook_in_ctx; 216 217 TAILQ_HEAD(, packet) outgoing; 218 }; 219 220 struct ssh * 221 ssh_alloc_session_state(void) 222 { 223 struct ssh *ssh = NULL; 224 struct session_state *state = NULL; 225 226 if ((ssh = calloc(1, sizeof(*ssh))) == NULL || 227 (state = calloc(1, sizeof(*state))) == NULL || 228 (state->input = sshbuf_new()) == NULL || 229 (state->output = sshbuf_new()) == NULL || 230 (state->outgoing_packet = sshbuf_new()) == NULL || 231 (state->incoming_packet = sshbuf_new()) == NULL) 232 goto fail; 233 TAILQ_INIT(&state->outgoing); 234 TAILQ_INIT(&ssh->private_keys); 235 TAILQ_INIT(&ssh->public_keys); 236 state->connection_in = -1; 237 state->connection_out = -1; 238 state->max_packet_size = 32768; 239 state->packet_timeout_ms = -1; 240 state->p_send.packets = state->p_read.packets = 0; 241 state->initialized = 1; 242 /* 243 * ssh_packet_send2() needs to queue packets until 244 * we've done the initial key exchange. 245 */ 246 state->rekeying = 1; 247 ssh->state = state; 248 return ssh; 249 fail: 250 if (state) { 251 sshbuf_free(state->input); 252 sshbuf_free(state->output); 253 sshbuf_free(state->incoming_packet); 254 sshbuf_free(state->outgoing_packet); 255 free(state); 256 } 257 free(ssh); 258 return NULL; 259 } 260 261 void 262 ssh_packet_set_input_hook(struct ssh *ssh, ssh_packet_hook_fn *hook, void *ctx) 263 { 264 ssh->state->hook_in = hook; 265 ssh->state->hook_in_ctx = ctx; 266 } 267 268 /* Returns nonzero if rekeying is in progress */ 269 int 270 ssh_packet_is_rekeying(struct ssh *ssh) 271 { 272 return ssh->state->rekeying || 273 (ssh->kex != NULL && ssh->kex->done == 0); 274 } 275 276 /* 277 * Sets the descriptors used for communication. 278 */ 279 struct ssh * 280 ssh_packet_set_connection(struct ssh *ssh, int fd_in, int fd_out) 281 { 282 struct session_state *state; 283 const struct sshcipher *none = cipher_by_name("none"); 284 int r; 285 286 if (none == NULL) { 287 error("%s: cannot load cipher 'none'", __func__); 288 return NULL; 289 } 290 if (ssh == NULL) 291 ssh = ssh_alloc_session_state(); 292 if (ssh == NULL) { 293 error("%s: cound not allocate state", __func__); 294 return NULL; 295 } 296 state = ssh->state; 297 state->connection_in = fd_in; 298 state->connection_out = fd_out; 299 if ((r = cipher_init(&state->send_context, none, 300 (const u_char *)"", 0, NULL, 0, CIPHER_ENCRYPT)) != 0 || 301 (r = cipher_init(&state->receive_context, none, 302 (const u_char *)"", 0, NULL, 0, CIPHER_DECRYPT)) != 0) { 303 error("%s: cipher_init failed: %s", __func__, ssh_err(r)); 304 free(ssh); /* XXX need ssh_free_session_state? */ 305 return NULL; 306 } 307 state->newkeys[MODE_IN] = state->newkeys[MODE_OUT] = NULL; 308 /* 309 * Cache the IP address of the remote connection for use in error 310 * messages that might be generated after the connection has closed. 311 */ 312 (void)ssh_remote_ipaddr(ssh); 313 return ssh; 314 } 315 316 void 317 ssh_packet_set_timeout(struct ssh *ssh, int timeout, int count) 318 { 319 struct session_state *state = ssh->state; 320 321 if (timeout <= 0 || count <= 0) { 322 state->packet_timeout_ms = -1; 323 return; 324 } 325 if ((INT_MAX / 1000) / count < timeout) 326 state->packet_timeout_ms = INT_MAX; 327 else 328 state->packet_timeout_ms = timeout * count * 1000; 329 } 330 331 void 332 ssh_packet_set_mux(struct ssh *ssh) 333 { 334 ssh->state->mux = 1; 335 ssh->state->rekeying = 0; 336 } 337 338 int 339 ssh_packet_get_mux(struct ssh *ssh) 340 { 341 return ssh->state->mux; 342 } 343 344 int 345 ssh_packet_set_log_preamble(struct ssh *ssh, const char *fmt, ...) 346 { 347 va_list args; 348 int r; 349 350 free(ssh->log_preamble); 351 if (fmt == NULL) 352 ssh->log_preamble = NULL; 353 else { 354 va_start(args, fmt); 355 r = vasprintf(&ssh->log_preamble, fmt, args); 356 va_end(args); 357 if (r < 0 || ssh->log_preamble == NULL) 358 return SSH_ERR_ALLOC_FAIL; 359 } 360 return 0; 361 } 362 363 int 364 ssh_packet_stop_discard(struct ssh *ssh) 365 { 366 struct session_state *state = ssh->state; 367 int r; 368 369 if (state->packet_discard_mac) { 370 char buf[1024]; 371 size_t dlen = PACKET_MAX_SIZE; 372 373 if (dlen > state->packet_discard_mac_already) 374 dlen -= state->packet_discard_mac_already; 375 memset(buf, 'a', sizeof(buf)); 376 while (sshbuf_len(state->incoming_packet) < dlen) 377 if ((r = sshbuf_put(state->incoming_packet, buf, 378 sizeof(buf))) != 0) 379 return r; 380 (void) mac_compute(state->packet_discard_mac, 381 state->p_read.seqnr, 382 sshbuf_ptr(state->incoming_packet), dlen, 383 NULL, 0); 384 } 385 logit("Finished discarding for %.200s port %d", 386 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 387 return SSH_ERR_MAC_INVALID; 388 } 389 390 static int 391 ssh_packet_start_discard(struct ssh *ssh, struct sshenc *enc, 392 struct sshmac *mac, size_t mac_already, u_int discard) 393 { 394 struct session_state *state = ssh->state; 395 int r; 396 397 if (enc == NULL || !cipher_is_cbc(enc->cipher) || (mac && mac->etm)) { 398 if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0) 399 return r; 400 return SSH_ERR_MAC_INVALID; 401 } 402 /* 403 * Record number of bytes over which the mac has already 404 * been computed in order to minimize timing attacks. 405 */ 406 if (mac && mac->enabled) { 407 state->packet_discard_mac = mac; 408 state->packet_discard_mac_already = mac_already; 409 } 410 if (sshbuf_len(state->input) >= discard) 411 return ssh_packet_stop_discard(ssh); 412 state->packet_discard = discard - sshbuf_len(state->input); 413 return 0; 414 } 415 416 /* Returns 1 if remote host is connected via socket, 0 if not. */ 417 418 int 419 ssh_packet_connection_is_on_socket(struct ssh *ssh) 420 { 421 struct session_state *state = ssh->state; 422 struct sockaddr_storage from, to; 423 socklen_t fromlen, tolen; 424 425 if (state->connection_in == -1 || state->connection_out == -1) 426 return 0; 427 428 /* filedescriptors in and out are the same, so it's a socket */ 429 if (state->connection_in == state->connection_out) 430 return 1; 431 fromlen = sizeof(from); 432 memset(&from, 0, sizeof(from)); 433 if (getpeername(state->connection_in, (struct sockaddr *)&from, 434 &fromlen) < 0) 435 return 0; 436 tolen = sizeof(to); 437 memset(&to, 0, sizeof(to)); 438 if (getpeername(state->connection_out, (struct sockaddr *)&to, 439 &tolen) < 0) 440 return 0; 441 if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0) 442 return 0; 443 if (from.ss_family != AF_INET && from.ss_family != AF_INET6) 444 return 0; 445 return 1; 446 } 447 448 void 449 ssh_packet_get_bytes(struct ssh *ssh, u_int64_t *ibytes, u_int64_t *obytes) 450 { 451 if (ibytes) 452 *ibytes = ssh->state->p_read.bytes; 453 if (obytes) 454 *obytes = ssh->state->p_send.bytes; 455 } 456 457 int 458 ssh_packet_connection_af(struct ssh *ssh) 459 { 460 struct sockaddr_storage to; 461 socklen_t tolen = sizeof(to); 462 463 memset(&to, 0, sizeof(to)); 464 if (getsockname(ssh->state->connection_out, (struct sockaddr *)&to, 465 &tolen) < 0) 466 return 0; 467 #ifdef IPV4_IN_IPV6 468 if (to.ss_family == AF_INET6 && 469 IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)&to)->sin6_addr)) 470 return AF_INET; 471 #endif 472 return to.ss_family; 473 } 474 475 /* Sets the connection into non-blocking mode. */ 476 477 void 478 ssh_packet_set_nonblocking(struct ssh *ssh) 479 { 480 /* Set the socket into non-blocking mode. */ 481 set_nonblock(ssh->state->connection_in); 482 483 if (ssh->state->connection_out != ssh->state->connection_in) 484 set_nonblock(ssh->state->connection_out); 485 } 486 487 /* Returns the socket used for reading. */ 488 489 int 490 ssh_packet_get_connection_in(struct ssh *ssh) 491 { 492 return ssh->state->connection_in; 493 } 494 495 /* Returns the descriptor used for writing. */ 496 497 int 498 ssh_packet_get_connection_out(struct ssh *ssh) 499 { 500 return ssh->state->connection_out; 501 } 502 503 /* 504 * Returns the IP-address of the remote host as a string. The returned 505 * string must not be freed. 506 */ 507 508 const char * 509 ssh_remote_ipaddr(struct ssh *ssh) 510 { 511 const int sock = ssh->state->connection_in; 512 513 /* Check whether we have cached the ipaddr. */ 514 if (ssh->remote_ipaddr == NULL) { 515 if (ssh_packet_connection_is_on_socket(ssh)) { 516 ssh->remote_ipaddr = get_peer_ipaddr(sock); 517 ssh->remote_port = get_peer_port(sock); 518 ssh->local_ipaddr = get_local_ipaddr(sock); 519 ssh->local_port = get_local_port(sock); 520 } else { 521 ssh->remote_ipaddr = strdup("UNKNOWN"); 522 ssh->remote_port = 65535; 523 ssh->local_ipaddr = strdup("UNKNOWN"); 524 ssh->local_port = 65535; 525 } 526 } 527 return ssh->remote_ipaddr; 528 } 529 530 /* Returns the port number of the remote host. */ 531 532 int 533 ssh_remote_port(struct ssh *ssh) 534 { 535 (void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */ 536 return ssh->remote_port; 537 } 538 539 /* 540 * Returns the IP-address of the local host as a string. The returned 541 * string must not be freed. 542 */ 543 544 const char * 545 ssh_local_ipaddr(struct ssh *ssh) 546 { 547 (void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */ 548 return ssh->local_ipaddr; 549 } 550 551 /* Returns the port number of the local host. */ 552 553 int 554 ssh_local_port(struct ssh *ssh) 555 { 556 (void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */ 557 return ssh->local_port; 558 } 559 560 /* Closes the connection and clears and frees internal data structures. */ 561 562 static void 563 ssh_packet_close_internal(struct ssh *ssh, int do_close) 564 { 565 struct session_state *state = ssh->state; 566 u_int mode; 567 568 if (!state->initialized) 569 return; 570 state->initialized = 0; 571 if (do_close) { 572 if (state->connection_in == state->connection_out) { 573 close(state->connection_out); 574 } else { 575 close(state->connection_in); 576 close(state->connection_out); 577 } 578 } 579 sshbuf_free(state->input); 580 sshbuf_free(state->output); 581 sshbuf_free(state->outgoing_packet); 582 sshbuf_free(state->incoming_packet); 583 for (mode = 0; mode < MODE_MAX; mode++) { 584 kex_free_newkeys(state->newkeys[mode]); /* current keys */ 585 state->newkeys[mode] = NULL; 586 ssh_clear_newkeys(ssh, mode); /* next keys */ 587 } 588 /* comression 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 cipher_free(state->send_context); 615 cipher_free(state->receive_context); 616 state->send_context = state->receive_context = NULL; 617 if (do_close) { 618 free(ssh->remote_ipaddr); 619 ssh->remote_ipaddr = NULL; 620 free(ssh->state); 621 ssh->state = NULL; 622 } 623 } 624 625 void 626 ssh_packet_close(struct ssh *ssh) 627 { 628 ssh_packet_close_internal(ssh, 1); 629 } 630 631 void 632 ssh_packet_clear_keys(struct ssh *ssh) 633 { 634 ssh_packet_close_internal(ssh, 0); 635 } 636 637 /* Sets remote side protocol flags. */ 638 639 void 640 ssh_packet_set_protocol_flags(struct ssh *ssh, u_int protocol_flags) 641 { 642 ssh->state->remote_protocol_flags = protocol_flags; 643 } 644 645 /* Returns the remote protocol flags set earlier by the above function. */ 646 647 u_int 648 ssh_packet_get_protocol_flags(struct ssh *ssh) 649 { 650 return ssh->state->remote_protocol_flags; 651 } 652 653 /* 654 * Starts packet compression from the next packet on in both directions. 655 * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip. 656 */ 657 658 static int 659 ssh_packet_init_compression(struct ssh *ssh) 660 { 661 if (!ssh->state->compression_buffer && 662 ((ssh->state->compression_buffer = sshbuf_new()) == NULL)) 663 return SSH_ERR_ALLOC_FAIL; 664 return 0; 665 } 666 667 static int 668 start_compression_out(struct ssh *ssh, int level) 669 { 670 if (level < 1 || level > 9) 671 return SSH_ERR_INVALID_ARGUMENT; 672 debug("Enabling compression at level %d.", level); 673 if (ssh->state->compression_out_started == 1) 674 deflateEnd(&ssh->state->compression_out_stream); 675 switch (deflateInit(&ssh->state->compression_out_stream, level)) { 676 case Z_OK: 677 ssh->state->compression_out_started = 1; 678 break; 679 case Z_MEM_ERROR: 680 return SSH_ERR_ALLOC_FAIL; 681 default: 682 return SSH_ERR_INTERNAL_ERROR; 683 } 684 return 0; 685 } 686 687 static int 688 start_compression_in(struct ssh *ssh) 689 { 690 if (ssh->state->compression_in_started == 1) 691 inflateEnd(&ssh->state->compression_in_stream); 692 switch (inflateInit(&ssh->state->compression_in_stream)) { 693 case Z_OK: 694 ssh->state->compression_in_started = 1; 695 break; 696 case Z_MEM_ERROR: 697 return SSH_ERR_ALLOC_FAIL; 698 default: 699 return SSH_ERR_INTERNAL_ERROR; 700 } 701 return 0; 702 } 703 704 int 705 ssh_packet_start_compression(struct ssh *ssh, int level) 706 { 707 int r; 708 709 if (ssh->state->packet_compression) 710 return SSH_ERR_INTERNAL_ERROR; 711 ssh->state->packet_compression = 1; 712 if ((r = ssh_packet_init_compression(ssh)) != 0 || 713 (r = start_compression_in(ssh)) != 0 || 714 (r = start_compression_out(ssh, level)) != 0) 715 return r; 716 return 0; 717 } 718 719 /* XXX remove need for separate compression buffer */ 720 static int 721 compress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out) 722 { 723 u_char buf[4096]; 724 int r, status; 725 726 if (ssh->state->compression_out_started != 1) 727 return SSH_ERR_INTERNAL_ERROR; 728 729 /* This case is not handled below. */ 730 if (sshbuf_len(in) == 0) 731 return 0; 732 733 /* Input is the contents of the input buffer. */ 734 if ((ssh->state->compression_out_stream.next_in = 735 sshbuf_mutable_ptr(in)) == NULL) 736 return SSH_ERR_INTERNAL_ERROR; 737 ssh->state->compression_out_stream.avail_in = sshbuf_len(in); 738 739 /* Loop compressing until deflate() returns with avail_out != 0. */ 740 do { 741 /* Set up fixed-size output buffer. */ 742 ssh->state->compression_out_stream.next_out = buf; 743 ssh->state->compression_out_stream.avail_out = sizeof(buf); 744 745 /* Compress as much data into the buffer as possible. */ 746 status = deflate(&ssh->state->compression_out_stream, 747 Z_PARTIAL_FLUSH); 748 switch (status) { 749 case Z_MEM_ERROR: 750 return SSH_ERR_ALLOC_FAIL; 751 case Z_OK: 752 /* Append compressed data to output_buffer. */ 753 if ((r = sshbuf_put(out, buf, sizeof(buf) - 754 ssh->state->compression_out_stream.avail_out)) != 0) 755 return r; 756 break; 757 case Z_STREAM_ERROR: 758 default: 759 ssh->state->compression_out_failures++; 760 return SSH_ERR_INVALID_FORMAT; 761 } 762 } while (ssh->state->compression_out_stream.avail_out == 0); 763 return 0; 764 } 765 766 static int 767 uncompress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out) 768 { 769 u_char buf[4096]; 770 int r, status; 771 772 if (ssh->state->compression_in_started != 1) 773 return SSH_ERR_INTERNAL_ERROR; 774 775 if ((ssh->state->compression_in_stream.next_in = 776 sshbuf_mutable_ptr(in)) == NULL) 777 return SSH_ERR_INTERNAL_ERROR; 778 ssh->state->compression_in_stream.avail_in = sshbuf_len(in); 779 780 for (;;) { 781 /* Set up fixed-size output buffer. */ 782 ssh->state->compression_in_stream.next_out = buf; 783 ssh->state->compression_in_stream.avail_out = sizeof(buf); 784 785 status = inflate(&ssh->state->compression_in_stream, 786 Z_PARTIAL_FLUSH); 787 switch (status) { 788 case Z_OK: 789 if ((r = sshbuf_put(out, buf, sizeof(buf) - 790 ssh->state->compression_in_stream.avail_out)) != 0) 791 return r; 792 break; 793 case Z_BUF_ERROR: 794 /* 795 * Comments in zlib.h say that we should keep calling 796 * inflate() until we get an error. This appears to 797 * be the error that we get. 798 */ 799 return 0; 800 case Z_DATA_ERROR: 801 return SSH_ERR_INVALID_FORMAT; 802 case Z_MEM_ERROR: 803 return SSH_ERR_ALLOC_FAIL; 804 case Z_STREAM_ERROR: 805 default: 806 ssh->state->compression_in_failures++; 807 return SSH_ERR_INTERNAL_ERROR; 808 } 809 } 810 /* NOTREACHED */ 811 } 812 813 void 814 ssh_clear_newkeys(struct ssh *ssh, int mode) 815 { 816 if (ssh->kex && ssh->kex->newkeys[mode]) { 817 kex_free_newkeys(ssh->kex->newkeys[mode]); 818 ssh->kex->newkeys[mode] = NULL; 819 } 820 } 821 822 int 823 ssh_set_newkeys(struct ssh *ssh, int mode) 824 { 825 struct session_state *state = ssh->state; 826 struct sshenc *enc; 827 struct sshmac *mac; 828 struct sshcomp *comp; 829 struct sshcipher_ctx **ccp; 830 struct packet_state *ps; 831 u_int64_t *max_blocks; 832 const char *wmsg; 833 int r, crypt_type; 834 835 debug2("set_newkeys: mode %d", mode); 836 837 if (mode == MODE_OUT) { 838 ccp = &state->send_context; 839 crypt_type = CIPHER_ENCRYPT; 840 ps = &state->p_send; 841 max_blocks = &state->max_blocks_out; 842 } else { 843 ccp = &state->receive_context; 844 crypt_type = CIPHER_DECRYPT; 845 ps = &state->p_read; 846 max_blocks = &state->max_blocks_in; 847 } 848 if (state->newkeys[mode] != NULL) { 849 debug("set_newkeys: rekeying, input %llu bytes %llu blocks, " 850 "output %llu bytes %llu blocks", 851 (unsigned long long)state->p_read.bytes, 852 (unsigned long long)state->p_read.blocks, 853 (unsigned long long)state->p_send.bytes, 854 (unsigned long long)state->p_send.blocks); 855 cipher_free(*ccp); 856 *ccp = NULL; 857 kex_free_newkeys(state->newkeys[mode]); 858 state->newkeys[mode] = NULL; 859 } 860 /* note that both bytes and the seqnr are not reset */ 861 ps->packets = ps->blocks = 0; 862 /* move newkeys from kex to state */ 863 if ((state->newkeys[mode] = ssh->kex->newkeys[mode]) == NULL) 864 return SSH_ERR_INTERNAL_ERROR; 865 ssh->kex->newkeys[mode] = NULL; 866 enc = &state->newkeys[mode]->enc; 867 mac = &state->newkeys[mode]->mac; 868 comp = &state->newkeys[mode]->comp; 869 if (cipher_authlen(enc->cipher) == 0) { 870 if ((r = mac_init(mac)) != 0) 871 return r; 872 } 873 mac->enabled = 1; 874 DBG(debug("cipher_init_context: %d", mode)); 875 if ((r = cipher_init(ccp, enc->cipher, enc->key, enc->key_len, 876 enc->iv, enc->iv_len, crypt_type)) != 0) 877 return r; 878 if (!state->cipher_warning_done && 879 (wmsg = cipher_warning_message(*ccp)) != NULL) { 880 error("Warning: %s", wmsg); 881 state->cipher_warning_done = 1; 882 } 883 /* Deleting the keys does not gain extra security */ 884 /* explicit_bzero(enc->iv, enc->block_size); 885 explicit_bzero(enc->key, enc->key_len); 886 explicit_bzero(mac->key, mac->key_len); */ 887 if ((comp->type == COMP_ZLIB || 888 (comp->type == COMP_DELAYED && 889 state->after_authentication)) && comp->enabled == 0) { 890 if ((r = ssh_packet_init_compression(ssh)) < 0) 891 return r; 892 if (mode == MODE_OUT) { 893 if ((r = start_compression_out(ssh, 6)) != 0) 894 return r; 895 } else { 896 if ((r = start_compression_in(ssh)) != 0) 897 return r; 898 } 899 comp->enabled = 1; 900 } 901 /* 902 * The 2^(blocksize*2) limit is too expensive for 3DES, 903 * so enforce a 1GB limit for small blocksizes. 904 * See RFC4344 section 3.2. 905 */ 906 if (enc->block_size >= 16) 907 *max_blocks = (u_int64_t)1 << (enc->block_size*2); 908 else 909 *max_blocks = ((u_int64_t)1 << 30) / enc->block_size; 910 if (state->rekey_limit) 911 *max_blocks = MINIMUM(*max_blocks, 912 state->rekey_limit / enc->block_size); 913 debug("rekey after %llu blocks", (unsigned long long)*max_blocks); 914 return 0; 915 } 916 917 #define MAX_PACKETS (1U<<31) 918 static int 919 ssh_packet_need_rekeying(struct ssh *ssh, u_int outbound_packet_len) 920 { 921 struct session_state *state = ssh->state; 922 u_int32_t out_blocks; 923 924 /* XXX client can't cope with rekeying pre-auth */ 925 if (!state->after_authentication) 926 return 0; 927 928 /* Haven't keyed yet or KEX in progress. */ 929 if (ssh->kex == NULL || ssh_packet_is_rekeying(ssh)) 930 return 0; 931 932 /* Peer can't rekey */ 933 if (ssh->compat & SSH_BUG_NOREKEY) 934 return 0; 935 936 /* 937 * Permit one packet in or out per rekey - this allows us to 938 * make progress when rekey limits are very small. 939 */ 940 if (state->p_send.packets == 0 && state->p_read.packets == 0) 941 return 0; 942 943 /* Time-based rekeying */ 944 if (state->rekey_interval != 0 && 945 (int64_t)state->rekey_time + state->rekey_interval <= monotime()) 946 return 1; 947 948 /* 949 * Always rekey when MAX_PACKETS sent in either direction 950 * As per RFC4344 section 3.1 we do this after 2^31 packets. 951 */ 952 if (state->p_send.packets > MAX_PACKETS || 953 state->p_read.packets > MAX_PACKETS) 954 return 1; 955 956 /* Rekey after (cipher-specific) maxiumum blocks */ 957 out_blocks = ROUNDUP(outbound_packet_len, 958 state->newkeys[MODE_OUT]->enc.block_size); 959 return (state->max_blocks_out && 960 (state->p_send.blocks + out_blocks > state->max_blocks_out)) || 961 (state->max_blocks_in && 962 (state->p_read.blocks > state->max_blocks_in)); 963 } 964 965 /* 966 * Delayed compression for SSH2 is enabled after authentication: 967 * This happens on the server side after a SSH2_MSG_USERAUTH_SUCCESS is sent, 968 * and on the client side after a SSH2_MSG_USERAUTH_SUCCESS is received. 969 */ 970 static int 971 ssh_packet_enable_delayed_compress(struct ssh *ssh) 972 { 973 struct session_state *state = ssh->state; 974 struct sshcomp *comp = NULL; 975 int r, mode; 976 977 /* 978 * Remember that we are past the authentication step, so rekeying 979 * with COMP_DELAYED will turn on compression immediately. 980 */ 981 state->after_authentication = 1; 982 for (mode = 0; mode < MODE_MAX; mode++) { 983 /* protocol error: USERAUTH_SUCCESS received before NEWKEYS */ 984 if (state->newkeys[mode] == NULL) 985 continue; 986 comp = &state->newkeys[mode]->comp; 987 if (comp && !comp->enabled && comp->type == COMP_DELAYED) { 988 if ((r = ssh_packet_init_compression(ssh)) != 0) 989 return r; 990 if (mode == MODE_OUT) { 991 if ((r = start_compression_out(ssh, 6)) != 0) 992 return r; 993 } else { 994 if ((r = start_compression_in(ssh)) != 0) 995 return r; 996 } 997 comp->enabled = 1; 998 } 999 } 1000 return 0; 1001 } 1002 1003 /* Used to mute debug logging for noisy packet types */ 1004 int 1005 ssh_packet_log_type(u_char type) 1006 { 1007 switch (type) { 1008 case SSH2_MSG_CHANNEL_DATA: 1009 case SSH2_MSG_CHANNEL_EXTENDED_DATA: 1010 case SSH2_MSG_CHANNEL_WINDOW_ADJUST: 1011 return 0; 1012 default: 1013 return 1; 1014 } 1015 } 1016 1017 /* 1018 * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue) 1019 */ 1020 int 1021 ssh_packet_send2_wrapped(struct ssh *ssh) 1022 { 1023 struct session_state *state = ssh->state; 1024 u_char type, *cp, macbuf[SSH_DIGEST_MAX_LENGTH]; 1025 u_char tmp, padlen, pad = 0; 1026 u_int authlen = 0, aadlen = 0; 1027 u_int len; 1028 struct sshenc *enc = NULL; 1029 struct sshmac *mac = NULL; 1030 struct sshcomp *comp = NULL; 1031 int r, block_size; 1032 1033 if (state->newkeys[MODE_OUT] != NULL) { 1034 enc = &state->newkeys[MODE_OUT]->enc; 1035 mac = &state->newkeys[MODE_OUT]->mac; 1036 comp = &state->newkeys[MODE_OUT]->comp; 1037 /* disable mac for authenticated encryption */ 1038 if ((authlen = cipher_authlen(enc->cipher)) != 0) 1039 mac = NULL; 1040 } 1041 block_size = enc ? enc->block_size : 8; 1042 aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0; 1043 1044 type = (sshbuf_ptr(state->outgoing_packet))[5]; 1045 if (ssh_packet_log_type(type)) 1046 debug3("send packet: type %u", type); 1047 #ifdef PACKET_DEBUG 1048 fprintf(stderr, "plain: "); 1049 sshbuf_dump(state->outgoing_packet, stderr); 1050 #endif 1051 1052 if (comp && comp->enabled) { 1053 len = sshbuf_len(state->outgoing_packet); 1054 /* skip header, compress only payload */ 1055 if ((r = sshbuf_consume(state->outgoing_packet, 5)) != 0) 1056 goto out; 1057 sshbuf_reset(state->compression_buffer); 1058 if ((r = compress_buffer(ssh, state->outgoing_packet, 1059 state->compression_buffer)) != 0) 1060 goto out; 1061 sshbuf_reset(state->outgoing_packet); 1062 if ((r = sshbuf_put(state->outgoing_packet, 1063 "\0\0\0\0\0", 5)) != 0 || 1064 (r = sshbuf_putb(state->outgoing_packet, 1065 state->compression_buffer)) != 0) 1066 goto out; 1067 DBG(debug("compression: raw %d compressed %zd", len, 1068 sshbuf_len(state->outgoing_packet))); 1069 } 1070 1071 /* sizeof (packet_len + pad_len + payload) */ 1072 len = sshbuf_len(state->outgoing_packet); 1073 1074 /* 1075 * calc size of padding, alloc space, get random data, 1076 * minimum padding is 4 bytes 1077 */ 1078 len -= aadlen; /* packet length is not encrypted for EtM modes */ 1079 padlen = block_size - (len % block_size); 1080 if (padlen < 4) 1081 padlen += block_size; 1082 if (state->extra_pad) { 1083 tmp = state->extra_pad; 1084 state->extra_pad = 1085 ROUNDUP(state->extra_pad, block_size); 1086 /* check if roundup overflowed */ 1087 if (state->extra_pad < tmp) 1088 return SSH_ERR_INVALID_ARGUMENT; 1089 tmp = (len + padlen) % state->extra_pad; 1090 /* Check whether pad calculation below will underflow */ 1091 if (tmp > state->extra_pad) 1092 return SSH_ERR_INVALID_ARGUMENT; 1093 pad = state->extra_pad - tmp; 1094 DBG(debug3("%s: adding %d (len %d padlen %d extra_pad %d)", 1095 __func__, pad, len, padlen, state->extra_pad)); 1096 tmp = padlen; 1097 padlen += pad; 1098 /* Check whether padlen calculation overflowed */ 1099 if (padlen < tmp) 1100 return SSH_ERR_INVALID_ARGUMENT; /* overflow */ 1101 state->extra_pad = 0; 1102 } 1103 if ((r = sshbuf_reserve(state->outgoing_packet, padlen, &cp)) != 0) 1104 goto out; 1105 if (enc && !cipher_ctx_is_plaintext(state->send_context)) { 1106 /* random padding */ 1107 arc4random_buf(cp, padlen); 1108 } else { 1109 /* clear padding */ 1110 explicit_bzero(cp, padlen); 1111 } 1112 /* sizeof (packet_len + pad_len + payload + padding) */ 1113 len = sshbuf_len(state->outgoing_packet); 1114 cp = sshbuf_mutable_ptr(state->outgoing_packet); 1115 if (cp == NULL) { 1116 r = SSH_ERR_INTERNAL_ERROR; 1117 goto out; 1118 } 1119 /* packet_length includes payload, padding and padding length field */ 1120 POKE_U32(cp, len - 4); 1121 cp[4] = padlen; 1122 DBG(debug("send: len %d (includes padlen %d, aadlen %d)", 1123 len, padlen, aadlen)); 1124 1125 /* compute MAC over seqnr and packet(length fields, payload, padding) */ 1126 if (mac && mac->enabled && !mac->etm) { 1127 if ((r = mac_compute(mac, state->p_send.seqnr, 1128 sshbuf_ptr(state->outgoing_packet), len, 1129 macbuf, sizeof(macbuf))) != 0) 1130 goto out; 1131 DBG(debug("done calc MAC out #%d", state->p_send.seqnr)); 1132 } 1133 /* encrypt packet and append to output buffer. */ 1134 if ((r = sshbuf_reserve(state->output, 1135 sshbuf_len(state->outgoing_packet) + authlen, &cp)) != 0) 1136 goto out; 1137 if ((r = cipher_crypt(state->send_context, state->p_send.seqnr, cp, 1138 sshbuf_ptr(state->outgoing_packet), 1139 len - aadlen, aadlen, authlen)) != 0) 1140 goto out; 1141 /* append unencrypted MAC */ 1142 if (mac && mac->enabled) { 1143 if (mac->etm) { 1144 /* EtM: compute mac over aadlen + cipher text */ 1145 if ((r = mac_compute(mac, state->p_send.seqnr, 1146 cp, len, macbuf, sizeof(macbuf))) != 0) 1147 goto out; 1148 DBG(debug("done calc MAC(EtM) out #%d", 1149 state->p_send.seqnr)); 1150 } 1151 if ((r = sshbuf_put(state->output, macbuf, mac->mac_len)) != 0) 1152 goto out; 1153 } 1154 #ifdef PACKET_DEBUG 1155 fprintf(stderr, "encrypted: "); 1156 sshbuf_dump(state->output, stderr); 1157 #endif 1158 /* increment sequence number for outgoing packets */ 1159 if (++state->p_send.seqnr == 0) 1160 logit("outgoing seqnr wraps around"); 1161 if (++state->p_send.packets == 0) 1162 if (!(ssh->compat & SSH_BUG_NOREKEY)) 1163 return SSH_ERR_NEED_REKEY; 1164 state->p_send.blocks += len / block_size; 1165 state->p_send.bytes += len; 1166 sshbuf_reset(state->outgoing_packet); 1167 1168 if (type == SSH2_MSG_NEWKEYS) 1169 r = ssh_set_newkeys(ssh, MODE_OUT); 1170 else if (type == SSH2_MSG_USERAUTH_SUCCESS && state->server_side) 1171 r = ssh_packet_enable_delayed_compress(ssh); 1172 else 1173 r = 0; 1174 out: 1175 return r; 1176 } 1177 1178 /* returns non-zero if the specified packet type is usec by KEX */ 1179 static int 1180 ssh_packet_type_is_kex(u_char type) 1181 { 1182 return 1183 type >= SSH2_MSG_TRANSPORT_MIN && 1184 type <= SSH2_MSG_TRANSPORT_MAX && 1185 type != SSH2_MSG_SERVICE_REQUEST && 1186 type != SSH2_MSG_SERVICE_ACCEPT && 1187 type != SSH2_MSG_EXT_INFO; 1188 } 1189 1190 int 1191 ssh_packet_send2(struct ssh *ssh) 1192 { 1193 struct session_state *state = ssh->state; 1194 struct packet *p; 1195 u_char type; 1196 int r, need_rekey; 1197 1198 if (sshbuf_len(state->outgoing_packet) < 6) 1199 return SSH_ERR_INTERNAL_ERROR; 1200 type = sshbuf_ptr(state->outgoing_packet)[5]; 1201 need_rekey = !ssh_packet_type_is_kex(type) && 1202 ssh_packet_need_rekeying(ssh, sshbuf_len(state->outgoing_packet)); 1203 1204 /* 1205 * During rekeying we can only send key exchange messages. 1206 * Queue everything else. 1207 */ 1208 if ((need_rekey || state->rekeying) && !ssh_packet_type_is_kex(type)) { 1209 if (need_rekey) 1210 debug3("%s: rekex triggered", __func__); 1211 debug("enqueue packet: %u", type); 1212 p = calloc(1, sizeof(*p)); 1213 if (p == NULL) 1214 return SSH_ERR_ALLOC_FAIL; 1215 p->type = type; 1216 p->payload = state->outgoing_packet; 1217 TAILQ_INSERT_TAIL(&state->outgoing, p, next); 1218 state->outgoing_packet = sshbuf_new(); 1219 if (state->outgoing_packet == NULL) 1220 return SSH_ERR_ALLOC_FAIL; 1221 if (need_rekey) { 1222 /* 1223 * This packet triggered a rekey, so send the 1224 * KEXINIT now. 1225 * NB. reenters this function via kex_start_rekex(). 1226 */ 1227 return kex_start_rekex(ssh); 1228 } 1229 return 0; 1230 } 1231 1232 /* rekeying starts with sending KEXINIT */ 1233 if (type == SSH2_MSG_KEXINIT) 1234 state->rekeying = 1; 1235 1236 if ((r = ssh_packet_send2_wrapped(ssh)) != 0) 1237 return r; 1238 1239 /* after a NEWKEYS message we can send the complete queue */ 1240 if (type == SSH2_MSG_NEWKEYS) { 1241 state->rekeying = 0; 1242 state->rekey_time = monotime(); 1243 while ((p = TAILQ_FIRST(&state->outgoing))) { 1244 type = p->type; 1245 /* 1246 * If this packet triggers a rekex, then skip the 1247 * remaining packets in the queue for now. 1248 * NB. re-enters this function via kex_start_rekex. 1249 */ 1250 if (ssh_packet_need_rekeying(ssh, 1251 sshbuf_len(p->payload))) { 1252 debug3("%s: queued packet triggered rekex", 1253 __func__); 1254 return kex_start_rekex(ssh); 1255 } 1256 debug("dequeue packet: %u", type); 1257 sshbuf_free(state->outgoing_packet); 1258 state->outgoing_packet = p->payload; 1259 TAILQ_REMOVE(&state->outgoing, p, next); 1260 memset(p, 0, sizeof(*p)); 1261 free(p); 1262 if ((r = ssh_packet_send2_wrapped(ssh)) != 0) 1263 return r; 1264 } 1265 } 1266 return 0; 1267 } 1268 1269 /* 1270 * Waits until a packet has been received, and returns its type. Note that 1271 * no other data is processed until this returns, so this function should not 1272 * be used during the interactive session. 1273 */ 1274 1275 int 1276 ssh_packet_read_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1277 { 1278 struct session_state *state = ssh->state; 1279 int len, r, ms_remain; 1280 fd_set *setp; 1281 char buf[8192]; 1282 struct timeval timeout, start, *timeoutp = NULL; 1283 1284 DBG(debug("packet_read()")); 1285 1286 setp = calloc(howmany(state->connection_in + 1, 1287 NFDBITS), sizeof(fd_mask)); 1288 if (setp == NULL) 1289 return SSH_ERR_ALLOC_FAIL; 1290 1291 /* 1292 * Since we are blocking, ensure that all written packets have 1293 * been sent. 1294 */ 1295 if ((r = ssh_packet_write_wait(ssh)) != 0) 1296 goto out; 1297 1298 /* Stay in the loop until we have received a complete packet. */ 1299 for (;;) { 1300 /* Try to read a packet from the buffer. */ 1301 r = ssh_packet_read_poll_seqnr(ssh, typep, seqnr_p); 1302 if (r != 0) 1303 break; 1304 /* If we got a packet, return it. */ 1305 if (*typep != SSH_MSG_NONE) 1306 break; 1307 /* 1308 * Otherwise, wait for some data to arrive, add it to the 1309 * buffer, and try again. 1310 */ 1311 memset(setp, 0, howmany(state->connection_in + 1, 1312 NFDBITS) * sizeof(fd_mask)); 1313 FD_SET(state->connection_in, setp); 1314 1315 if (state->packet_timeout_ms > 0) { 1316 ms_remain = state->packet_timeout_ms; 1317 timeoutp = &timeout; 1318 } 1319 /* Wait for some data to arrive. */ 1320 for (;;) { 1321 if (state->packet_timeout_ms != -1) { 1322 ms_to_timeval(&timeout, ms_remain); 1323 gettimeofday(&start, NULL); 1324 } 1325 if ((r = select(state->connection_in + 1, setp, 1326 NULL, NULL, timeoutp)) >= 0) 1327 break; 1328 if (errno != EAGAIN && errno != EINTR && 1329 errno != EWOULDBLOCK) 1330 break; 1331 if (state->packet_timeout_ms == -1) 1332 continue; 1333 ms_subtract_diff(&start, &ms_remain); 1334 if (ms_remain <= 0) { 1335 r = 0; 1336 break; 1337 } 1338 } 1339 if (r == 0) { 1340 r = SSH_ERR_CONN_TIMEOUT; 1341 goto out; 1342 } 1343 /* Read data from the socket. */ 1344 len = read(state->connection_in, buf, sizeof(buf)); 1345 if (len == 0) { 1346 r = SSH_ERR_CONN_CLOSED; 1347 goto out; 1348 } 1349 if (len < 0) { 1350 r = SSH_ERR_SYSTEM_ERROR; 1351 goto out; 1352 } 1353 1354 /* Append it to the buffer. */ 1355 if ((r = ssh_packet_process_incoming(ssh, buf, len)) != 0) 1356 goto out; 1357 } 1358 out: 1359 free(setp); 1360 return r; 1361 } 1362 1363 int 1364 ssh_packet_read(struct ssh *ssh) 1365 { 1366 u_char type; 1367 int r; 1368 1369 if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0) 1370 fatal("%s: %s", __func__, ssh_err(r)); 1371 return type; 1372 } 1373 1374 /* 1375 * Waits until a packet has been received, verifies that its type matches 1376 * that given, and gives a fatal error and exits if there is a mismatch. 1377 */ 1378 1379 int 1380 ssh_packet_read_expect(struct ssh *ssh, u_int expected_type) 1381 { 1382 int r; 1383 u_char type; 1384 1385 if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0) 1386 return r; 1387 if (type != expected_type) { 1388 if ((r = sshpkt_disconnect(ssh, 1389 "Protocol error: expected packet type %d, got %d", 1390 expected_type, type)) != 0) 1391 return r; 1392 return SSH_ERR_PROTOCOL_ERROR; 1393 } 1394 return 0; 1395 } 1396 1397 static int 1398 ssh_packet_read_poll2_mux(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1399 { 1400 struct session_state *state = ssh->state; 1401 const u_char *cp; 1402 size_t need; 1403 int r; 1404 1405 if (ssh->kex) 1406 return SSH_ERR_INTERNAL_ERROR; 1407 *typep = SSH_MSG_NONE; 1408 cp = sshbuf_ptr(state->input); 1409 if (state->packlen == 0) { 1410 if (sshbuf_len(state->input) < 4 + 1) 1411 return 0; /* packet is incomplete */ 1412 state->packlen = PEEK_U32(cp); 1413 if (state->packlen < 4 + 1 || 1414 state->packlen > PACKET_MAX_SIZE) 1415 return SSH_ERR_MESSAGE_INCOMPLETE; 1416 } 1417 need = state->packlen + 4; 1418 if (sshbuf_len(state->input) < need) 1419 return 0; /* packet is incomplete */ 1420 sshbuf_reset(state->incoming_packet); 1421 if ((r = sshbuf_put(state->incoming_packet, cp + 4, 1422 state->packlen)) != 0 || 1423 (r = sshbuf_consume(state->input, need)) != 0 || 1424 (r = sshbuf_get_u8(state->incoming_packet, NULL)) != 0 || 1425 (r = sshbuf_get_u8(state->incoming_packet, typep)) != 0) 1426 return r; 1427 if (ssh_packet_log_type(*typep)) 1428 debug3("%s: type %u", __func__, *typep); 1429 /* sshbuf_dump(state->incoming_packet, stderr); */ 1430 /* reset for next packet */ 1431 state->packlen = 0; 1432 return r; 1433 } 1434 1435 int 1436 ssh_packet_read_poll2(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1437 { 1438 struct session_state *state = ssh->state; 1439 u_int padlen, need; 1440 u_char *cp; 1441 u_int maclen, aadlen = 0, authlen = 0, block_size; 1442 struct sshenc *enc = NULL; 1443 struct sshmac *mac = NULL; 1444 struct sshcomp *comp = NULL; 1445 int r; 1446 1447 if (state->mux) 1448 return ssh_packet_read_poll2_mux(ssh, typep, seqnr_p); 1449 1450 *typep = SSH_MSG_NONE; 1451 1452 if (state->packet_discard) 1453 return 0; 1454 1455 if (state->newkeys[MODE_IN] != NULL) { 1456 enc = &state->newkeys[MODE_IN]->enc; 1457 mac = &state->newkeys[MODE_IN]->mac; 1458 comp = &state->newkeys[MODE_IN]->comp; 1459 /* disable mac for authenticated encryption */ 1460 if ((authlen = cipher_authlen(enc->cipher)) != 0) 1461 mac = NULL; 1462 } 1463 maclen = mac && mac->enabled ? mac->mac_len : 0; 1464 block_size = enc ? enc->block_size : 8; 1465 aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0; 1466 1467 if (aadlen && state->packlen == 0) { 1468 if (cipher_get_length(state->receive_context, 1469 &state->packlen, state->p_read.seqnr, 1470 sshbuf_ptr(state->input), sshbuf_len(state->input)) != 0) 1471 return 0; 1472 if (state->packlen < 1 + 4 || 1473 state->packlen > PACKET_MAX_SIZE) { 1474 #ifdef PACKET_DEBUG 1475 sshbuf_dump(state->input, stderr); 1476 #endif 1477 logit("Bad packet length %u.", state->packlen); 1478 if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0) 1479 return r; 1480 return SSH_ERR_CONN_CORRUPT; 1481 } 1482 sshbuf_reset(state->incoming_packet); 1483 } else if (state->packlen == 0) { 1484 /* 1485 * check if input size is less than the cipher block size, 1486 * decrypt first block and extract length of incoming packet 1487 */ 1488 if (sshbuf_len(state->input) < block_size) 1489 return 0; 1490 sshbuf_reset(state->incoming_packet); 1491 if ((r = sshbuf_reserve(state->incoming_packet, block_size, 1492 &cp)) != 0) 1493 goto out; 1494 if ((r = cipher_crypt(state->receive_context, 1495 state->p_send.seqnr, cp, sshbuf_ptr(state->input), 1496 block_size, 0, 0)) != 0) 1497 goto out; 1498 state->packlen = PEEK_U32(sshbuf_ptr(state->incoming_packet)); 1499 if (state->packlen < 1 + 4 || 1500 state->packlen > PACKET_MAX_SIZE) { 1501 #ifdef PACKET_DEBUG 1502 fprintf(stderr, "input: \n"); 1503 sshbuf_dump(state->input, stderr); 1504 fprintf(stderr, "incoming_packet: \n"); 1505 sshbuf_dump(state->incoming_packet, stderr); 1506 #endif 1507 logit("Bad packet length %u.", state->packlen); 1508 return ssh_packet_start_discard(ssh, enc, mac, 0, 1509 PACKET_MAX_SIZE); 1510 } 1511 if ((r = sshbuf_consume(state->input, block_size)) != 0) 1512 goto out; 1513 } 1514 DBG(debug("input: packet len %u", state->packlen+4)); 1515 1516 if (aadlen) { 1517 /* only the payload is encrypted */ 1518 need = state->packlen; 1519 } else { 1520 /* 1521 * the payload size and the payload are encrypted, but we 1522 * have a partial packet of block_size bytes 1523 */ 1524 need = 4 + state->packlen - block_size; 1525 } 1526 DBG(debug("partial packet: block %d, need %d, maclen %d, authlen %d," 1527 " aadlen %d", block_size, need, maclen, authlen, aadlen)); 1528 if (need % block_size != 0) { 1529 logit("padding error: need %d block %d mod %d", 1530 need, block_size, need % block_size); 1531 return ssh_packet_start_discard(ssh, enc, mac, 0, 1532 PACKET_MAX_SIZE - block_size); 1533 } 1534 /* 1535 * check if the entire packet has been received and 1536 * decrypt into incoming_packet: 1537 * 'aadlen' bytes are unencrypted, but authenticated. 1538 * 'need' bytes are encrypted, followed by either 1539 * 'authlen' bytes of authentication tag or 1540 * 'maclen' bytes of message authentication code. 1541 */ 1542 if (sshbuf_len(state->input) < aadlen + need + authlen + maclen) 1543 return 0; /* packet is incomplete */ 1544 #ifdef PACKET_DEBUG 1545 fprintf(stderr, "read_poll enc/full: "); 1546 sshbuf_dump(state->input, stderr); 1547 #endif 1548 /* EtM: check mac over encrypted input */ 1549 if (mac && mac->enabled && mac->etm) { 1550 if ((r = mac_check(mac, state->p_read.seqnr, 1551 sshbuf_ptr(state->input), aadlen + need, 1552 sshbuf_ptr(state->input) + aadlen + need + authlen, 1553 maclen)) != 0) { 1554 if (r == SSH_ERR_MAC_INVALID) 1555 logit("Corrupted MAC on input."); 1556 goto out; 1557 } 1558 } 1559 if ((r = sshbuf_reserve(state->incoming_packet, aadlen + need, 1560 &cp)) != 0) 1561 goto out; 1562 if ((r = cipher_crypt(state->receive_context, state->p_read.seqnr, cp, 1563 sshbuf_ptr(state->input), need, aadlen, authlen)) != 0) 1564 goto out; 1565 if ((r = sshbuf_consume(state->input, aadlen + need + authlen)) != 0) 1566 goto out; 1567 if (mac && mac->enabled) { 1568 /* Not EtM: check MAC over cleartext */ 1569 if (!mac->etm && (r = mac_check(mac, state->p_read.seqnr, 1570 sshbuf_ptr(state->incoming_packet), 1571 sshbuf_len(state->incoming_packet), 1572 sshbuf_ptr(state->input), maclen)) != 0) { 1573 if (r != SSH_ERR_MAC_INVALID) 1574 goto out; 1575 logit("Corrupted MAC on input."); 1576 if (need + block_size > PACKET_MAX_SIZE) 1577 return SSH_ERR_INTERNAL_ERROR; 1578 return ssh_packet_start_discard(ssh, enc, mac, 1579 sshbuf_len(state->incoming_packet), 1580 PACKET_MAX_SIZE - need - block_size); 1581 } 1582 /* Remove MAC from input buffer */ 1583 DBG(debug("MAC #%d ok", state->p_read.seqnr)); 1584 if ((r = sshbuf_consume(state->input, mac->mac_len)) != 0) 1585 goto out; 1586 } 1587 if (seqnr_p != NULL) 1588 *seqnr_p = state->p_read.seqnr; 1589 if (++state->p_read.seqnr == 0) 1590 logit("incoming seqnr wraps around"); 1591 if (++state->p_read.packets == 0) 1592 if (!(ssh->compat & SSH_BUG_NOREKEY)) 1593 return SSH_ERR_NEED_REKEY; 1594 state->p_read.blocks += (state->packlen + 4) / block_size; 1595 state->p_read.bytes += state->packlen + 4; 1596 1597 /* get padlen */ 1598 padlen = sshbuf_ptr(state->incoming_packet)[4]; 1599 DBG(debug("input: padlen %d", padlen)); 1600 if (padlen < 4) { 1601 if ((r = sshpkt_disconnect(ssh, 1602 "Corrupted padlen %d on input.", padlen)) != 0 || 1603 (r = ssh_packet_write_wait(ssh)) != 0) 1604 return r; 1605 return SSH_ERR_CONN_CORRUPT; 1606 } 1607 1608 /* skip packet size + padlen, discard padding */ 1609 if ((r = sshbuf_consume(state->incoming_packet, 4 + 1)) != 0 || 1610 ((r = sshbuf_consume_end(state->incoming_packet, padlen)) != 0)) 1611 goto out; 1612 1613 DBG(debug("input: len before de-compress %zd", 1614 sshbuf_len(state->incoming_packet))); 1615 if (comp && comp->enabled) { 1616 sshbuf_reset(state->compression_buffer); 1617 if ((r = uncompress_buffer(ssh, state->incoming_packet, 1618 state->compression_buffer)) != 0) 1619 goto out; 1620 sshbuf_reset(state->incoming_packet); 1621 if ((r = sshbuf_putb(state->incoming_packet, 1622 state->compression_buffer)) != 0) 1623 goto out; 1624 DBG(debug("input: len after de-compress %zd", 1625 sshbuf_len(state->incoming_packet))); 1626 } 1627 /* 1628 * get packet type, implies consume. 1629 * return length of payload (without type field) 1630 */ 1631 if ((r = sshbuf_get_u8(state->incoming_packet, typep)) != 0) 1632 goto out; 1633 if (ssh_packet_log_type(*typep)) 1634 debug3("receive packet: type %u", *typep); 1635 if (*typep < SSH2_MSG_MIN || *typep >= SSH2_MSG_LOCAL_MIN) { 1636 if ((r = sshpkt_disconnect(ssh, 1637 "Invalid ssh2 packet type: %d", *typep)) != 0 || 1638 (r = ssh_packet_write_wait(ssh)) != 0) 1639 return r; 1640 return SSH_ERR_PROTOCOL_ERROR; 1641 } 1642 if (state->hook_in != NULL && 1643 (r = state->hook_in(ssh, state->incoming_packet, typep, 1644 state->hook_in_ctx)) != 0) 1645 return r; 1646 if (*typep == SSH2_MSG_USERAUTH_SUCCESS && !state->server_side) 1647 r = ssh_packet_enable_delayed_compress(ssh); 1648 else 1649 r = 0; 1650 #ifdef PACKET_DEBUG 1651 fprintf(stderr, "read/plain[%d]:\r\n", *typep); 1652 sshbuf_dump(state->incoming_packet, stderr); 1653 #endif 1654 /* reset for next packet */ 1655 state->packlen = 0; 1656 1657 /* do we need to rekey? */ 1658 if (ssh_packet_need_rekeying(ssh, 0)) { 1659 debug3("%s: rekex triggered", __func__); 1660 if ((r = kex_start_rekex(ssh)) != 0) 1661 return r; 1662 } 1663 out: 1664 return r; 1665 } 1666 1667 int 1668 ssh_packet_read_poll_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1669 { 1670 struct session_state *state = ssh->state; 1671 u_int reason, seqnr; 1672 int r; 1673 u_char *msg; 1674 1675 for (;;) { 1676 msg = NULL; 1677 r = ssh_packet_read_poll2(ssh, typep, seqnr_p); 1678 if (r != 0) 1679 return r; 1680 if (*typep) { 1681 state->keep_alive_timeouts = 0; 1682 DBG(debug("received packet type %d", *typep)); 1683 } 1684 switch (*typep) { 1685 case SSH2_MSG_IGNORE: 1686 debug3("Received SSH2_MSG_IGNORE"); 1687 break; 1688 case SSH2_MSG_DEBUG: 1689 if ((r = sshpkt_get_u8(ssh, NULL)) != 0 || 1690 (r = sshpkt_get_string(ssh, &msg, NULL)) != 0 || 1691 (r = sshpkt_get_string(ssh, NULL, NULL)) != 0) { 1692 free(msg); 1693 return r; 1694 } 1695 debug("Remote: %.900s", msg); 1696 free(msg); 1697 break; 1698 case SSH2_MSG_DISCONNECT: 1699 if ((r = sshpkt_get_u32(ssh, &reason)) != 0 || 1700 (r = sshpkt_get_string(ssh, &msg, NULL)) != 0) 1701 return r; 1702 /* Ignore normal client exit notifications */ 1703 do_log2(ssh->state->server_side && 1704 reason == SSH2_DISCONNECT_BY_APPLICATION ? 1705 SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_ERROR, 1706 "Received disconnect from %s port %d:" 1707 "%u: %.400s", ssh_remote_ipaddr(ssh), 1708 ssh_remote_port(ssh), reason, msg); 1709 free(msg); 1710 return SSH_ERR_DISCONNECTED; 1711 case SSH2_MSG_UNIMPLEMENTED: 1712 if ((r = sshpkt_get_u32(ssh, &seqnr)) != 0) 1713 return r; 1714 debug("Received SSH2_MSG_UNIMPLEMENTED for %u", 1715 seqnr); 1716 break; 1717 default: 1718 return 0; 1719 } 1720 } 1721 } 1722 1723 /* 1724 * Buffers the given amount of input characters. This is intended to be used 1725 * together with packet_read_poll. 1726 */ 1727 1728 int 1729 ssh_packet_process_incoming(struct ssh *ssh, const char *buf, u_int len) 1730 { 1731 struct session_state *state = ssh->state; 1732 int r; 1733 1734 if (state->packet_discard) { 1735 state->keep_alive_timeouts = 0; /* ?? */ 1736 if (len >= state->packet_discard) { 1737 if ((r = ssh_packet_stop_discard(ssh)) != 0) 1738 return r; 1739 } 1740 state->packet_discard -= len; 1741 return 0; 1742 } 1743 if ((r = sshbuf_put(ssh->state->input, buf, len)) != 0) 1744 return r; 1745 1746 return 0; 1747 } 1748 1749 int 1750 ssh_packet_remaining(struct ssh *ssh) 1751 { 1752 return sshbuf_len(ssh->state->incoming_packet); 1753 } 1754 1755 /* 1756 * Sends a diagnostic message from the server to the client. This message 1757 * can be sent at any time (but not while constructing another message). The 1758 * message is printed immediately, but only if the client is being executed 1759 * in verbose mode. These messages are primarily intended to ease debugging 1760 * authentication problems. The length of the formatted message must not 1761 * exceed 1024 bytes. This will automatically call ssh_packet_write_wait. 1762 */ 1763 void 1764 ssh_packet_send_debug(struct ssh *ssh, const char *fmt,...) 1765 { 1766 char buf[1024]; 1767 va_list args; 1768 int r; 1769 1770 if ((ssh->compat & SSH_BUG_DEBUG)) 1771 return; 1772 1773 va_start(args, fmt); 1774 vsnprintf(buf, sizeof(buf), fmt, args); 1775 va_end(args); 1776 1777 if ((r = sshpkt_start(ssh, SSH2_MSG_DEBUG)) != 0 || 1778 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* always display */ 1779 (r = sshpkt_put_cstring(ssh, buf)) != 0 || 1780 (r = sshpkt_put_cstring(ssh, "")) != 0 || 1781 (r = sshpkt_send(ssh)) != 0 || 1782 (r = ssh_packet_write_wait(ssh)) != 0) 1783 fatal("%s: %s", __func__, ssh_err(r)); 1784 } 1785 1786 static void 1787 fmt_connection_id(struct ssh *ssh, char *s, size_t l) 1788 { 1789 snprintf(s, l, "%.200s%s%s port %d", 1790 ssh->log_preamble ? ssh->log_preamble : "", 1791 ssh->log_preamble ? " " : "", 1792 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 1793 } 1794 1795 /* 1796 * Pretty-print connection-terminating errors and exit. 1797 */ 1798 void 1799 sshpkt_fatal(struct ssh *ssh, const char *tag, int r) 1800 { 1801 char remote_id[512]; 1802 1803 fmt_connection_id(ssh, remote_id, sizeof(remote_id)); 1804 1805 switch (r) { 1806 case SSH_ERR_CONN_CLOSED: 1807 ssh_packet_clear_keys(ssh); 1808 logdie("Connection closed by %s", remote_id); 1809 case SSH_ERR_CONN_TIMEOUT: 1810 ssh_packet_clear_keys(ssh); 1811 logdie("Connection %s %s timed out", 1812 ssh->state->server_side ? "from" : "to", remote_id); 1813 case SSH_ERR_DISCONNECTED: 1814 ssh_packet_clear_keys(ssh); 1815 logdie("Disconnected from %s", remote_id); 1816 case SSH_ERR_SYSTEM_ERROR: 1817 if (errno == ECONNRESET) { 1818 ssh_packet_clear_keys(ssh); 1819 logdie("Connection reset by %s", remote_id); 1820 } 1821 /* FALLTHROUGH */ 1822 case SSH_ERR_NO_CIPHER_ALG_MATCH: 1823 case SSH_ERR_NO_MAC_ALG_MATCH: 1824 case SSH_ERR_NO_COMPRESS_ALG_MATCH: 1825 case SSH_ERR_NO_KEX_ALG_MATCH: 1826 case SSH_ERR_NO_HOSTKEY_ALG_MATCH: 1827 if (ssh && ssh->kex && ssh->kex->failed_choice) { 1828 ssh_packet_clear_keys(ssh); 1829 logdie("Unable to negotiate with %s: %s. " 1830 "Their offer: %s", remote_id, ssh_err(r), 1831 ssh->kex->failed_choice); 1832 } 1833 /* FALLTHROUGH */ 1834 default: 1835 ssh_packet_clear_keys(ssh); 1836 logdie("%s%sConnection %s %s: %s", 1837 tag != NULL ? tag : "", tag != NULL ? ": " : "", 1838 ssh->state->server_side ? "from" : "to", 1839 remote_id, ssh_err(r)); 1840 } 1841 } 1842 1843 /* 1844 * Logs the error plus constructs and sends a disconnect packet, closes the 1845 * connection, and exits. This function never returns. The error message 1846 * should not contain a newline. The length of the formatted message must 1847 * not exceed 1024 bytes. 1848 */ 1849 void 1850 ssh_packet_disconnect(struct ssh *ssh, const char *fmt,...) 1851 { 1852 char buf[1024], remote_id[512]; 1853 va_list args; 1854 static int disconnecting = 0; 1855 int r; 1856 1857 if (disconnecting) /* Guard against recursive invocations. */ 1858 fatal("packet_disconnect called recursively."); 1859 disconnecting = 1; 1860 1861 /* 1862 * Format the message. Note that the caller must make sure the 1863 * message is of limited size. 1864 */ 1865 fmt_connection_id(ssh, remote_id, sizeof(remote_id)); 1866 va_start(args, fmt); 1867 vsnprintf(buf, sizeof(buf), fmt, args); 1868 va_end(args); 1869 1870 /* Display the error locally */ 1871 logit("Disconnecting %s: %.100s", remote_id, buf); 1872 1873 /* 1874 * Send the disconnect message to the other side, and wait 1875 * for it to get sent. 1876 */ 1877 if ((r = sshpkt_disconnect(ssh, "%s", buf)) != 0) 1878 sshpkt_fatal(ssh, __func__, r); 1879 1880 if ((r = ssh_packet_write_wait(ssh)) != 0) 1881 sshpkt_fatal(ssh, __func__, r); 1882 1883 /* Close the connection. */ 1884 ssh_packet_close(ssh); 1885 cleanup_exit(255); 1886 } 1887 1888 /* 1889 * Checks if there is any buffered output, and tries to write some of 1890 * the output. 1891 */ 1892 int 1893 ssh_packet_write_poll(struct ssh *ssh) 1894 { 1895 struct session_state *state = ssh->state; 1896 int len = sshbuf_len(state->output); 1897 int r; 1898 1899 if (len > 0) { 1900 len = write(state->connection_out, 1901 sshbuf_ptr(state->output), len); 1902 if (len == -1) { 1903 if (errno == EINTR || errno == EAGAIN || 1904 errno == EWOULDBLOCK) 1905 return 0; 1906 return SSH_ERR_SYSTEM_ERROR; 1907 } 1908 if (len == 0) 1909 return SSH_ERR_CONN_CLOSED; 1910 if ((r = sshbuf_consume(state->output, len)) != 0) 1911 return r; 1912 } 1913 return 0; 1914 } 1915 1916 /* 1917 * Calls packet_write_poll repeatedly until all pending output data has been 1918 * written. 1919 */ 1920 int 1921 ssh_packet_write_wait(struct ssh *ssh) 1922 { 1923 fd_set *setp; 1924 int ret, r, ms_remain = 0; 1925 struct timeval start, timeout, *timeoutp = NULL; 1926 struct session_state *state = ssh->state; 1927 1928 setp = calloc(howmany(state->connection_out + 1, 1929 NFDBITS), sizeof(fd_mask)); 1930 if (setp == NULL) 1931 return SSH_ERR_ALLOC_FAIL; 1932 if ((r = ssh_packet_write_poll(ssh)) != 0) { 1933 free(setp); 1934 return r; 1935 } 1936 while (ssh_packet_have_data_to_write(ssh)) { 1937 memset(setp, 0, howmany(state->connection_out + 1, 1938 NFDBITS) * sizeof(fd_mask)); 1939 FD_SET(state->connection_out, setp); 1940 1941 if (state->packet_timeout_ms > 0) { 1942 ms_remain = state->packet_timeout_ms; 1943 timeoutp = &timeout; 1944 } 1945 for (;;) { 1946 if (state->packet_timeout_ms != -1) { 1947 ms_to_timeval(&timeout, ms_remain); 1948 gettimeofday(&start, NULL); 1949 } 1950 if ((ret = select(state->connection_out + 1, 1951 NULL, setp, NULL, timeoutp)) >= 0) 1952 break; 1953 if (errno != EAGAIN && errno != EINTR && 1954 errno != EWOULDBLOCK) 1955 break; 1956 if (state->packet_timeout_ms == -1) 1957 continue; 1958 ms_subtract_diff(&start, &ms_remain); 1959 if (ms_remain <= 0) { 1960 ret = 0; 1961 break; 1962 } 1963 } 1964 if (ret == 0) { 1965 free(setp); 1966 return SSH_ERR_CONN_TIMEOUT; 1967 } 1968 if ((r = ssh_packet_write_poll(ssh)) != 0) { 1969 free(setp); 1970 return r; 1971 } 1972 } 1973 free(setp); 1974 return 0; 1975 } 1976 1977 /* Returns true if there is buffered data to write to the connection. */ 1978 1979 int 1980 ssh_packet_have_data_to_write(struct ssh *ssh) 1981 { 1982 return sshbuf_len(ssh->state->output) != 0; 1983 } 1984 1985 /* Returns true if there is not too much data to write to the connection. */ 1986 1987 int 1988 ssh_packet_not_very_much_data_to_write(struct ssh *ssh) 1989 { 1990 if (ssh->state->interactive_mode) 1991 return sshbuf_len(ssh->state->output) < 16384; 1992 else 1993 return sshbuf_len(ssh->state->output) < 128 * 1024; 1994 } 1995 1996 void 1997 ssh_packet_set_tos(struct ssh *ssh, int tos) 1998 { 1999 #ifndef IP_TOS_IS_BROKEN 2000 if (!ssh_packet_connection_is_on_socket(ssh) || tos == INT_MAX) 2001 return; 2002 switch (ssh_packet_connection_af(ssh)) { 2003 # ifdef IP_TOS 2004 case AF_INET: 2005 debug3("%s: set IP_TOS 0x%02x", __func__, tos); 2006 if (setsockopt(ssh->state->connection_in, 2007 IPPROTO_IP, IP_TOS, &tos, sizeof(tos)) < 0) 2008 error("setsockopt IP_TOS %d: %.100s:", 2009 tos, strerror(errno)); 2010 break; 2011 # endif /* IP_TOS */ 2012 # ifdef IPV6_TCLASS 2013 case AF_INET6: 2014 debug3("%s: set IPV6_TCLASS 0x%02x", __func__, tos); 2015 if (setsockopt(ssh->state->connection_in, 2016 IPPROTO_IPV6, IPV6_TCLASS, &tos, sizeof(tos)) < 0) 2017 error("setsockopt IPV6_TCLASS %d: %.100s:", 2018 tos, strerror(errno)); 2019 break; 2020 # endif /* IPV6_TCLASS */ 2021 } 2022 #endif /* IP_TOS_IS_BROKEN */ 2023 } 2024 2025 /* Informs that the current session is interactive. Sets IP flags for that. */ 2026 2027 void 2028 ssh_packet_set_interactive(struct ssh *ssh, int interactive, int qos_interactive, int qos_bulk) 2029 { 2030 struct session_state *state = ssh->state; 2031 2032 if (state->set_interactive_called) 2033 return; 2034 state->set_interactive_called = 1; 2035 2036 /* Record that we are in interactive mode. */ 2037 state->interactive_mode = interactive; 2038 2039 /* Only set socket options if using a socket. */ 2040 if (!ssh_packet_connection_is_on_socket(ssh)) 2041 return; 2042 set_nodelay(state->connection_in); 2043 ssh_packet_set_tos(ssh, interactive ? qos_interactive : 2044 qos_bulk); 2045 } 2046 2047 /* Returns true if the current connection is interactive. */ 2048 2049 int 2050 ssh_packet_is_interactive(struct ssh *ssh) 2051 { 2052 return ssh->state->interactive_mode; 2053 } 2054 2055 int 2056 ssh_packet_set_maxsize(struct ssh *ssh, u_int s) 2057 { 2058 struct session_state *state = ssh->state; 2059 2060 if (state->set_maxsize_called) { 2061 logit("packet_set_maxsize: called twice: old %d new %d", 2062 state->max_packet_size, s); 2063 return -1; 2064 } 2065 if (s < 4 * 1024 || s > 1024 * 1024) { 2066 logit("packet_set_maxsize: bad size %d", s); 2067 return -1; 2068 } 2069 state->set_maxsize_called = 1; 2070 debug("packet_set_maxsize: setting to %d", s); 2071 state->max_packet_size = s; 2072 return s; 2073 } 2074 2075 int 2076 ssh_packet_inc_alive_timeouts(struct ssh *ssh) 2077 { 2078 return ++ssh->state->keep_alive_timeouts; 2079 } 2080 2081 void 2082 ssh_packet_set_alive_timeouts(struct ssh *ssh, int ka) 2083 { 2084 ssh->state->keep_alive_timeouts = ka; 2085 } 2086 2087 u_int 2088 ssh_packet_get_maxsize(struct ssh *ssh) 2089 { 2090 return ssh->state->max_packet_size; 2091 } 2092 2093 void 2094 ssh_packet_set_rekey_limits(struct ssh *ssh, u_int64_t bytes, u_int32_t seconds) 2095 { 2096 debug3("rekey after %llu bytes, %u seconds", (unsigned long long)bytes, 2097 (unsigned int)seconds); 2098 ssh->state->rekey_limit = bytes; 2099 ssh->state->rekey_interval = seconds; 2100 } 2101 2102 time_t 2103 ssh_packet_get_rekey_timeout(struct ssh *ssh) 2104 { 2105 time_t seconds; 2106 2107 seconds = ssh->state->rekey_time + ssh->state->rekey_interval - 2108 monotime(); 2109 return (seconds <= 0 ? 1 : seconds); 2110 } 2111 2112 void 2113 ssh_packet_set_server(struct ssh *ssh) 2114 { 2115 ssh->state->server_side = 1; 2116 } 2117 2118 void 2119 ssh_packet_set_authenticated(struct ssh *ssh) 2120 { 2121 ssh->state->after_authentication = 1; 2122 } 2123 2124 void * 2125 ssh_packet_get_input(struct ssh *ssh) 2126 { 2127 return (void *)ssh->state->input; 2128 } 2129 2130 void * 2131 ssh_packet_get_output(struct ssh *ssh) 2132 { 2133 return (void *)ssh->state->output; 2134 } 2135 2136 /* Reset after_authentication and reset compression in post-auth privsep */ 2137 static int 2138 ssh_packet_set_postauth(struct ssh *ssh) 2139 { 2140 int r; 2141 2142 debug("%s: called", __func__); 2143 /* This was set in net child, but is not visible in user child */ 2144 ssh->state->after_authentication = 1; 2145 ssh->state->rekeying = 0; 2146 if ((r = ssh_packet_enable_delayed_compress(ssh)) != 0) 2147 return r; 2148 return 0; 2149 } 2150 2151 /* Packet state (de-)serialization for privsep */ 2152 2153 /* turn kex into a blob for packet state serialization */ 2154 static int 2155 kex_to_blob(struct sshbuf *m, struct kex *kex) 2156 { 2157 int r; 2158 2159 if ((r = sshbuf_put_string(m, kex->session_id, 2160 kex->session_id_len)) != 0 || 2161 (r = sshbuf_put_u32(m, kex->we_need)) != 0 || 2162 (r = sshbuf_put_u32(m, kex->hostkey_type)) != 0 || 2163 (r = sshbuf_put_u32(m, kex->kex_type)) != 0 || 2164 (r = sshbuf_put_stringb(m, kex->my)) != 0 || 2165 (r = sshbuf_put_stringb(m, kex->peer)) != 0 || 2166 (r = sshbuf_put_u32(m, kex->flags)) != 0 || 2167 (r = sshbuf_put_cstring(m, kex->client_version_string)) != 0 || 2168 (r = sshbuf_put_cstring(m, kex->server_version_string)) != 0) 2169 return r; 2170 return 0; 2171 } 2172 2173 /* turn key exchange results into a blob for packet state serialization */ 2174 static int 2175 newkeys_to_blob(struct sshbuf *m, struct ssh *ssh, int mode) 2176 { 2177 struct sshbuf *b; 2178 struct sshcipher_ctx *cc; 2179 struct sshcomp *comp; 2180 struct sshenc *enc; 2181 struct sshmac *mac; 2182 struct newkeys *newkey; 2183 int r; 2184 2185 if ((newkey = ssh->state->newkeys[mode]) == NULL) 2186 return SSH_ERR_INTERNAL_ERROR; 2187 enc = &newkey->enc; 2188 mac = &newkey->mac; 2189 comp = &newkey->comp; 2190 cc = (mode == MODE_OUT) ? ssh->state->send_context : 2191 ssh->state->receive_context; 2192 if ((r = cipher_get_keyiv(cc, enc->iv, enc->iv_len)) != 0) 2193 return r; 2194 if ((b = sshbuf_new()) == NULL) 2195 return SSH_ERR_ALLOC_FAIL; 2196 if ((r = sshbuf_put_cstring(b, enc->name)) != 0 || 2197 (r = sshbuf_put_u32(b, enc->enabled)) != 0 || 2198 (r = sshbuf_put_u32(b, enc->block_size)) != 0 || 2199 (r = sshbuf_put_string(b, enc->key, enc->key_len)) != 0 || 2200 (r = sshbuf_put_string(b, enc->iv, enc->iv_len)) != 0) 2201 goto out; 2202 if (cipher_authlen(enc->cipher) == 0) { 2203 if ((r = sshbuf_put_cstring(b, mac->name)) != 0 || 2204 (r = sshbuf_put_u32(b, mac->enabled)) != 0 || 2205 (r = sshbuf_put_string(b, mac->key, mac->key_len)) != 0) 2206 goto out; 2207 } 2208 if ((r = sshbuf_put_u32(b, comp->type)) != 0 || 2209 (r = sshbuf_put_cstring(b, comp->name)) != 0) 2210 goto out; 2211 r = sshbuf_put_stringb(m, b); 2212 out: 2213 sshbuf_free(b); 2214 return r; 2215 } 2216 2217 /* serialize packet state into a blob */ 2218 int 2219 ssh_packet_get_state(struct ssh *ssh, struct sshbuf *m) 2220 { 2221 struct session_state *state = ssh->state; 2222 int r; 2223 2224 if ((r = kex_to_blob(m, ssh->kex)) != 0 || 2225 (r = newkeys_to_blob(m, ssh, MODE_OUT)) != 0 || 2226 (r = newkeys_to_blob(m, ssh, MODE_IN)) != 0 || 2227 (r = sshbuf_put_u64(m, state->rekey_limit)) != 0 || 2228 (r = sshbuf_put_u32(m, state->rekey_interval)) != 0 || 2229 (r = sshbuf_put_u32(m, state->p_send.seqnr)) != 0 || 2230 (r = sshbuf_put_u64(m, state->p_send.blocks)) != 0 || 2231 (r = sshbuf_put_u32(m, state->p_send.packets)) != 0 || 2232 (r = sshbuf_put_u64(m, state->p_send.bytes)) != 0 || 2233 (r = sshbuf_put_u32(m, state->p_read.seqnr)) != 0 || 2234 (r = sshbuf_put_u64(m, state->p_read.blocks)) != 0 || 2235 (r = sshbuf_put_u32(m, state->p_read.packets)) != 0 || 2236 (r = sshbuf_put_u64(m, state->p_read.bytes)) != 0 || 2237 (r = sshbuf_put_stringb(m, state->input)) != 0 || 2238 (r = sshbuf_put_stringb(m, state->output)) != 0) 2239 return r; 2240 2241 return 0; 2242 } 2243 2244 /* restore key exchange results from blob for packet state de-serialization */ 2245 static int 2246 newkeys_from_blob(struct sshbuf *m, struct ssh *ssh, int mode) 2247 { 2248 struct sshbuf *b = NULL; 2249 struct sshcomp *comp; 2250 struct sshenc *enc; 2251 struct sshmac *mac; 2252 struct newkeys *newkey = NULL; 2253 size_t keylen, ivlen, maclen; 2254 int r; 2255 2256 if ((newkey = calloc(1, sizeof(*newkey))) == NULL) { 2257 r = SSH_ERR_ALLOC_FAIL; 2258 goto out; 2259 } 2260 if ((r = sshbuf_froms(m, &b)) != 0) 2261 goto out; 2262 #ifdef DEBUG_PK 2263 sshbuf_dump(b, stderr); 2264 #endif 2265 enc = &newkey->enc; 2266 mac = &newkey->mac; 2267 comp = &newkey->comp; 2268 2269 if ((r = sshbuf_get_cstring(b, &enc->name, NULL)) != 0 || 2270 (r = sshbuf_get_u32(b, (u_int *)&enc->enabled)) != 0 || 2271 (r = sshbuf_get_u32(b, &enc->block_size)) != 0 || 2272 (r = sshbuf_get_string(b, &enc->key, &keylen)) != 0 || 2273 (r = sshbuf_get_string(b, &enc->iv, &ivlen)) != 0) 2274 goto out; 2275 if ((enc->cipher = cipher_by_name(enc->name)) == NULL) { 2276 r = SSH_ERR_INVALID_FORMAT; 2277 goto out; 2278 } 2279 if (cipher_authlen(enc->cipher) == 0) { 2280 if ((r = sshbuf_get_cstring(b, &mac->name, NULL)) != 0) 2281 goto out; 2282 if ((r = mac_setup(mac, mac->name)) != 0) 2283 goto out; 2284 if ((r = sshbuf_get_u32(b, (u_int *)&mac->enabled)) != 0 || 2285 (r = sshbuf_get_string(b, &mac->key, &maclen)) != 0) 2286 goto out; 2287 if (maclen > mac->key_len) { 2288 r = SSH_ERR_INVALID_FORMAT; 2289 goto out; 2290 } 2291 mac->key_len = maclen; 2292 } 2293 if ((r = sshbuf_get_u32(b, &comp->type)) != 0 || 2294 (r = sshbuf_get_cstring(b, &comp->name, NULL)) != 0) 2295 goto out; 2296 if (sshbuf_len(b) != 0) { 2297 r = SSH_ERR_INVALID_FORMAT; 2298 goto out; 2299 } 2300 enc->key_len = keylen; 2301 enc->iv_len = ivlen; 2302 ssh->kex->newkeys[mode] = newkey; 2303 newkey = NULL; 2304 r = 0; 2305 out: 2306 free(newkey); 2307 sshbuf_free(b); 2308 return r; 2309 } 2310 2311 /* restore kex from blob for packet state de-serialization */ 2312 static int 2313 kex_from_blob(struct sshbuf *m, struct kex **kexp) 2314 { 2315 struct kex *kex; 2316 int r; 2317 2318 if ((kex = calloc(1, sizeof(struct kex))) == NULL || 2319 (kex->my = sshbuf_new()) == NULL || 2320 (kex->peer = sshbuf_new()) == NULL) { 2321 r = SSH_ERR_ALLOC_FAIL; 2322 goto out; 2323 } 2324 if ((r = sshbuf_get_string(m, &kex->session_id, &kex->session_id_len)) != 0 || 2325 (r = sshbuf_get_u32(m, &kex->we_need)) != 0 || 2326 (r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_type)) != 0 || 2327 (r = sshbuf_get_u32(m, &kex->kex_type)) != 0 || 2328 (r = sshbuf_get_stringb(m, kex->my)) != 0 || 2329 (r = sshbuf_get_stringb(m, kex->peer)) != 0 || 2330 (r = sshbuf_get_u32(m, &kex->flags)) != 0 || 2331 (r = sshbuf_get_cstring(m, &kex->client_version_string, NULL)) != 0 || 2332 (r = sshbuf_get_cstring(m, &kex->server_version_string, NULL)) != 0) 2333 goto out; 2334 kex->server = 1; 2335 kex->done = 1; 2336 r = 0; 2337 out: 2338 if (r != 0 || kexp == NULL) { 2339 if (kex != NULL) { 2340 sshbuf_free(kex->my); 2341 sshbuf_free(kex->peer); 2342 free(kex); 2343 } 2344 if (kexp != NULL) 2345 *kexp = NULL; 2346 } else { 2347 *kexp = kex; 2348 } 2349 return r; 2350 } 2351 2352 /* 2353 * Restore packet state from content of blob 'm' (de-serialization). 2354 * Note that 'm' will be partially consumed on parsing or any other errors. 2355 */ 2356 int 2357 ssh_packet_set_state(struct ssh *ssh, struct sshbuf *m) 2358 { 2359 struct session_state *state = ssh->state; 2360 const u_char *input, *output; 2361 size_t ilen, olen; 2362 int r; 2363 2364 if ((r = kex_from_blob(m, &ssh->kex)) != 0 || 2365 (r = newkeys_from_blob(m, ssh, MODE_OUT)) != 0 || 2366 (r = newkeys_from_blob(m, ssh, MODE_IN)) != 0 || 2367 (r = sshbuf_get_u64(m, &state->rekey_limit)) != 0 || 2368 (r = sshbuf_get_u32(m, &state->rekey_interval)) != 0 || 2369 (r = sshbuf_get_u32(m, &state->p_send.seqnr)) != 0 || 2370 (r = sshbuf_get_u64(m, &state->p_send.blocks)) != 0 || 2371 (r = sshbuf_get_u32(m, &state->p_send.packets)) != 0 || 2372 (r = sshbuf_get_u64(m, &state->p_send.bytes)) != 0 || 2373 (r = sshbuf_get_u32(m, &state->p_read.seqnr)) != 0 || 2374 (r = sshbuf_get_u64(m, &state->p_read.blocks)) != 0 || 2375 (r = sshbuf_get_u32(m, &state->p_read.packets)) != 0 || 2376 (r = sshbuf_get_u64(m, &state->p_read.bytes)) != 0) 2377 return r; 2378 /* 2379 * We set the time here so that in post-auth privsep slave we 2380 * count from the completion of the authentication. 2381 */ 2382 state->rekey_time = monotime(); 2383 /* XXX ssh_set_newkeys overrides p_read.packets? XXX */ 2384 if ((r = ssh_set_newkeys(ssh, MODE_IN)) != 0 || 2385 (r = ssh_set_newkeys(ssh, MODE_OUT)) != 0) 2386 return r; 2387 2388 if ((r = ssh_packet_set_postauth(ssh)) != 0) 2389 return r; 2390 2391 sshbuf_reset(state->input); 2392 sshbuf_reset(state->output); 2393 if ((r = sshbuf_get_string_direct(m, &input, &ilen)) != 0 || 2394 (r = sshbuf_get_string_direct(m, &output, &olen)) != 0 || 2395 (r = sshbuf_put(state->input, input, ilen)) != 0 || 2396 (r = sshbuf_put(state->output, output, olen)) != 0) 2397 return r; 2398 2399 if (sshbuf_len(m)) 2400 return SSH_ERR_INVALID_FORMAT; 2401 debug3("%s: done", __func__); 2402 return 0; 2403 } 2404 2405 /* NEW API */ 2406 2407 /* put data to the outgoing packet */ 2408 2409 int 2410 sshpkt_put(struct ssh *ssh, const void *v, size_t len) 2411 { 2412 return sshbuf_put(ssh->state->outgoing_packet, v, len); 2413 } 2414 2415 int 2416 sshpkt_putb(struct ssh *ssh, const struct sshbuf *b) 2417 { 2418 return sshbuf_putb(ssh->state->outgoing_packet, b); 2419 } 2420 2421 int 2422 sshpkt_put_u8(struct ssh *ssh, u_char val) 2423 { 2424 return sshbuf_put_u8(ssh->state->outgoing_packet, val); 2425 } 2426 2427 int 2428 sshpkt_put_u32(struct ssh *ssh, u_int32_t val) 2429 { 2430 return sshbuf_put_u32(ssh->state->outgoing_packet, val); 2431 } 2432 2433 int 2434 sshpkt_put_u64(struct ssh *ssh, u_int64_t val) 2435 { 2436 return sshbuf_put_u64(ssh->state->outgoing_packet, val); 2437 } 2438 2439 int 2440 sshpkt_put_string(struct ssh *ssh, const void *v, size_t len) 2441 { 2442 return sshbuf_put_string(ssh->state->outgoing_packet, v, len); 2443 } 2444 2445 int 2446 sshpkt_put_cstring(struct ssh *ssh, const void *v) 2447 { 2448 return sshbuf_put_cstring(ssh->state->outgoing_packet, v); 2449 } 2450 2451 int 2452 sshpkt_put_stringb(struct ssh *ssh, const struct sshbuf *v) 2453 { 2454 return sshbuf_put_stringb(ssh->state->outgoing_packet, v); 2455 } 2456 2457 #ifdef WITH_OPENSSL 2458 #ifdef OPENSSL_HAS_ECC 2459 int 2460 sshpkt_put_ec(struct ssh *ssh, const EC_POINT *v, const EC_GROUP *g) 2461 { 2462 return sshbuf_put_ec(ssh->state->outgoing_packet, v, g); 2463 } 2464 #endif /* OPENSSL_HAS_ECC */ 2465 2466 2467 int 2468 sshpkt_put_bignum2(struct ssh *ssh, const BIGNUM *v) 2469 { 2470 return sshbuf_put_bignum2(ssh->state->outgoing_packet, v); 2471 } 2472 #endif /* WITH_OPENSSL */ 2473 2474 /* fetch data from the incoming packet */ 2475 2476 int 2477 sshpkt_get(struct ssh *ssh, void *valp, size_t len) 2478 { 2479 return sshbuf_get(ssh->state->incoming_packet, valp, len); 2480 } 2481 2482 int 2483 sshpkt_get_u8(struct ssh *ssh, u_char *valp) 2484 { 2485 return sshbuf_get_u8(ssh->state->incoming_packet, valp); 2486 } 2487 2488 int 2489 sshpkt_get_u32(struct ssh *ssh, u_int32_t *valp) 2490 { 2491 return sshbuf_get_u32(ssh->state->incoming_packet, valp); 2492 } 2493 2494 int 2495 sshpkt_get_u64(struct ssh *ssh, u_int64_t *valp) 2496 { 2497 return sshbuf_get_u64(ssh->state->incoming_packet, valp); 2498 } 2499 2500 int 2501 sshpkt_get_string(struct ssh *ssh, u_char **valp, size_t *lenp) 2502 { 2503 return sshbuf_get_string(ssh->state->incoming_packet, valp, lenp); 2504 } 2505 2506 int 2507 sshpkt_get_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp) 2508 { 2509 return sshbuf_get_string_direct(ssh->state->incoming_packet, valp, lenp); 2510 } 2511 2512 int 2513 sshpkt_peek_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp) 2514 { 2515 return sshbuf_peek_string_direct(ssh->state->incoming_packet, valp, lenp); 2516 } 2517 2518 int 2519 sshpkt_get_cstring(struct ssh *ssh, char **valp, size_t *lenp) 2520 { 2521 return sshbuf_get_cstring(ssh->state->incoming_packet, valp, lenp); 2522 } 2523 2524 #ifdef WITH_OPENSSL 2525 #ifdef OPENSSL_HAS_ECC 2526 int 2527 sshpkt_get_ec(struct ssh *ssh, EC_POINT *v, const EC_GROUP *g) 2528 { 2529 return sshbuf_get_ec(ssh->state->incoming_packet, v, g); 2530 } 2531 #endif /* OPENSSL_HAS_ECC */ 2532 2533 2534 int 2535 sshpkt_get_bignum2(struct ssh *ssh, BIGNUM *v) 2536 { 2537 return sshbuf_get_bignum2(ssh->state->incoming_packet, v); 2538 } 2539 #endif /* WITH_OPENSSL */ 2540 2541 int 2542 sshpkt_get_end(struct ssh *ssh) 2543 { 2544 if (sshbuf_len(ssh->state->incoming_packet) > 0) 2545 return SSH_ERR_UNEXPECTED_TRAILING_DATA; 2546 return 0; 2547 } 2548 2549 const u_char * 2550 sshpkt_ptr(struct ssh *ssh, size_t *lenp) 2551 { 2552 if (lenp != NULL) 2553 *lenp = sshbuf_len(ssh->state->incoming_packet); 2554 return sshbuf_ptr(ssh->state->incoming_packet); 2555 } 2556 2557 /* start a new packet */ 2558 2559 int 2560 sshpkt_start(struct ssh *ssh, u_char type) 2561 { 2562 u_char buf[6]; /* u32 packet length, u8 pad len, u8 type */ 2563 2564 DBG(debug("packet_start[%d]", type)); 2565 memset(buf, 0, sizeof(buf)); 2566 buf[sizeof(buf) - 1] = type; 2567 sshbuf_reset(ssh->state->outgoing_packet); 2568 return sshbuf_put(ssh->state->outgoing_packet, buf, sizeof(buf)); 2569 } 2570 2571 static int 2572 ssh_packet_send_mux(struct ssh *ssh) 2573 { 2574 struct session_state *state = ssh->state; 2575 u_char type, *cp; 2576 size_t len; 2577 int r; 2578 2579 if (ssh->kex) 2580 return SSH_ERR_INTERNAL_ERROR; 2581 len = sshbuf_len(state->outgoing_packet); 2582 if (len < 6) 2583 return SSH_ERR_INTERNAL_ERROR; 2584 cp = sshbuf_mutable_ptr(state->outgoing_packet); 2585 type = cp[5]; 2586 if (ssh_packet_log_type(type)) 2587 debug3("%s: type %u", __func__, type); 2588 /* drop everything, but the connection protocol */ 2589 if (type >= SSH2_MSG_CONNECTION_MIN && 2590 type <= SSH2_MSG_CONNECTION_MAX) { 2591 POKE_U32(cp, len - 4); 2592 if ((r = sshbuf_putb(state->output, 2593 state->outgoing_packet)) != 0) 2594 return r; 2595 /* sshbuf_dump(state->output, stderr); */ 2596 } 2597 sshbuf_reset(state->outgoing_packet); 2598 return 0; 2599 } 2600 2601 /* 2602 * 9.2. Ignored Data Message 2603 * 2604 * byte SSH_MSG_IGNORE 2605 * string data 2606 * 2607 * All implementations MUST understand (and ignore) this message at any 2608 * time (after receiving the protocol version). No implementation is 2609 * required to send them. This message can be used as an additional 2610 * protection measure against advanced traffic analysis techniques. 2611 */ 2612 int 2613 sshpkt_msg_ignore(struct ssh *ssh, u_int nbytes) 2614 { 2615 u_int32_t rnd = 0; 2616 int r; 2617 u_int i; 2618 2619 if ((r = sshpkt_start(ssh, SSH2_MSG_IGNORE)) != 0 || 2620 (r = sshpkt_put_u32(ssh, nbytes)) != 0) 2621 return r; 2622 for (i = 0; i < nbytes; i++) { 2623 if (i % 4 == 0) 2624 rnd = arc4random(); 2625 if ((r = sshpkt_put_u8(ssh, (u_char)rnd & 0xff)) != 0) 2626 return r; 2627 rnd >>= 8; 2628 } 2629 return 0; 2630 } 2631 2632 /* send it */ 2633 2634 int 2635 sshpkt_send(struct ssh *ssh) 2636 { 2637 if (ssh->state && ssh->state->mux) 2638 return ssh_packet_send_mux(ssh); 2639 return ssh_packet_send2(ssh); 2640 } 2641 2642 int 2643 sshpkt_disconnect(struct ssh *ssh, const char *fmt,...) 2644 { 2645 char buf[1024]; 2646 va_list args; 2647 int r; 2648 2649 va_start(args, fmt); 2650 vsnprintf(buf, sizeof(buf), fmt, args); 2651 va_end(args); 2652 2653 if ((r = sshpkt_start(ssh, SSH2_MSG_DISCONNECT)) != 0 || 2654 (r = sshpkt_put_u32(ssh, SSH2_DISCONNECT_PROTOCOL_ERROR)) != 0 || 2655 (r = sshpkt_put_cstring(ssh, buf)) != 0 || 2656 (r = sshpkt_put_cstring(ssh, "")) != 0 || 2657 (r = sshpkt_send(ssh)) != 0) 2658 return r; 2659 return 0; 2660 } 2661 2662 /* roundup current message to pad bytes */ 2663 int 2664 sshpkt_add_padding(struct ssh *ssh, u_char pad) 2665 { 2666 ssh->state->extra_pad = pad; 2667 return 0; 2668 } 2669