packet.c revision 1.35
1/* $NetBSD: packet.c,v 1.35 2018/10/02 22:40:28 christos Exp $ */ 2/* $OpenBSD: packet.c,v 1.277 2018/07/16 03:09:13 djm Exp $ */ 3 4/* 5 * Author: Tatu Ylonen <ylo@cs.hut.fi> 6 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 7 * All rights reserved 8 * This file contains code implementing the packet protocol and communication 9 * with the other side. This same code is used both on client and server side. 10 * 11 * As far as I am concerned, the code I have written for this software 12 * can be used freely for any purpose. Any derived versions of this 13 * software must be clearly marked as such, and if the derived work is 14 * incompatible with the protocol description in the RFC file, it must be 15 * called by a name other than "ssh" or "Secure Shell". 16 * 17 * 18 * SSH2 packet format added by Markus Friedl. 19 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. 20 * 21 * Redistribution and use in source and binary forms, with or without 22 * modification, are permitted provided that the following conditions 23 * are met: 24 * 1. Redistributions of source code must retain the above copyright 25 * notice, this list of conditions and the following disclaimer. 26 * 2. Redistributions in binary form must reproduce the above copyright 27 * notice, this list of conditions and the following disclaimer in the 28 * documentation and/or other materials provided with the distribution. 29 * 30 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 31 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 33 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 34 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 35 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 39 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 40 */ 41 42#include "includes.h" 43__RCSID("$NetBSD: packet.c,v 1.35 2018/10/02 22:40:28 christos Exp $"); 44 45#include <sys/param.h> /* MIN roundup */ 46#include <sys/types.h> 47#include <sys/queue.h> 48#include <sys/socket.h> 49#include <sys/time.h> 50#include <netinet/in.h> 51#include <netinet/ip.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 "xmalloc.h" 67#include "crc32.h" 68#include "compat.h" 69#include "ssh2.h" 70#include "cipher.h" 71#include "sshkey.h" 72#include "kex.h" 73#include "digest.h" 74#include "mac.h" 75#include "log.h" 76#include "canohost.h" 77#include "misc.h" 78#include "channels.h" 79#include "ssh.h" 80#include "packet.h" 81#include "ssherr.h" 82#include "sshbuf.h" 83 84#ifdef PACKET_DEBUG 85#define DBG(x) x 86#else 87#define DBG(x) 88#endif 89 90#define PACKET_MAX_SIZE (256 * 1024) 91 92struct packet_state { 93 u_int32_t seqnr; 94 u_int32_t packets; 95 u_int64_t blocks; 96 u_int64_t bytes; 97}; 98 99struct packet { 100 TAILQ_ENTRY(packet) next; 101 u_char type; 102 struct sshbuf *payload; 103}; 104 105struct session_state { 106 /* 107 * This variable contains the file descriptors used for 108 * communicating with the other side. connection_in is used for 109 * reading; connection_out for writing. These can be the same 110 * descriptor, in which case it is assumed to be a socket. 111 */ 112 int connection_in; 113 int connection_out; 114 115 /* Protocol flags for the remote side. */ 116 u_int remote_protocol_flags; 117 118 /* Encryption context for receiving data. Only used for decryption. */ 119 struct sshcipher_ctx *receive_context; 120 121 /* Encryption context for sending data. Only used for encryption. */ 122 struct sshcipher_ctx *send_context; 123 124 /* Buffer for raw input data from the socket. */ 125 struct sshbuf *input; 126 127 /* Buffer for raw output data going to the socket. */ 128 struct sshbuf *output; 129 130 /* Buffer for the partial outgoing packet being constructed. */ 131 struct sshbuf *outgoing_packet; 132 133 /* Buffer for the incoming packet currently being processed. */ 134 struct sshbuf *incoming_packet; 135 136 /* Scratch buffer for packet compression/decompression. */ 137 struct sshbuf *compression_buffer; 138 139 /* Incoming/outgoing compression dictionaries */ 140 z_stream compression_in_stream; 141 z_stream compression_out_stream; 142 int compression_in_started; 143 int compression_out_started; 144 int compression_in_failures; 145 int compression_out_failures; 146 147 /* default maximum packet size */ 148 u_int max_packet_size; 149 150 /* Flag indicating whether this module has been initialized. */ 151 int initialized; 152 153 /* Set to true if the connection is interactive. */ 154 int interactive_mode; 155 156 /* Set to true if we are the server side. */ 157 int server_side; 158 159 /* Set to true if we are authenticated. */ 160 int after_authentication; 161 162 int keep_alive_timeouts; 163 164 /* The maximum time that we will wait to send or receive a packet */ 165 int packet_timeout_ms; 166 167 /* Session key information for Encryption and MAC */ 168 struct newkeys *newkeys[MODE_MAX]; 169 struct packet_state p_read, p_send; 170 171 /* Volume-based rekeying */ 172 u_int64_t max_blocks_in, max_blocks_out, rekey_limit; 173 174 /* Time-based rekeying */ 175 u_int32_t rekey_interval; /* how often in seconds */ 176 time_t rekey_time; /* time of last rekeying */ 177 178 /* roundup current message to extra_pad bytes */ 179 u_char extra_pad; 180 181 /* XXX discard incoming data after MAC error */ 182 u_int packet_discard; 183 size_t packet_discard_mac_already; 184 struct sshmac *packet_discard_mac; 185 186 /* Used in packet_read_poll2() */ 187 u_int packlen; 188 189 /* Used in packet_send2 */ 190 int rekeying; 191 192 /* Used in ssh_packet_send_mux() */ 193 int mux; 194 195 /* Used in packet_set_interactive */ 196 int set_interactive_called; 197 198 /* Used in packet_set_maxsize */ 199 int set_maxsize_called; 200 201 /* One-off warning about weak ciphers */ 202 int cipher_warning_done; 203 204 /* Hook for fuzzing inbound packets */ 205 ssh_packet_hook_fn *hook_in; 206 void *hook_in_ctx; 207 208 TAILQ_HEAD(, packet) outgoing; 209}; 210 211struct ssh * 212ssh_alloc_session_state(void) 213{ 214 struct ssh *ssh = NULL; 215 struct session_state *state = NULL; 216 217 if ((ssh = calloc(1, sizeof(*ssh))) == NULL || 218 (state = calloc(1, sizeof(*state))) == NULL || 219 (state->input = sshbuf_new()) == NULL || 220 (state->output = sshbuf_new()) == NULL || 221 (state->outgoing_packet = sshbuf_new()) == NULL || 222 (state->incoming_packet = sshbuf_new()) == NULL) 223 goto fail; 224 TAILQ_INIT(&state->outgoing); 225 TAILQ_INIT(&ssh->private_keys); 226 TAILQ_INIT(&ssh->public_keys); 227 state->connection_in = -1; 228 state->connection_out = -1; 229 state->max_packet_size = 32768; 230 state->packet_timeout_ms = -1; 231 state->p_send.packets = state->p_read.packets = 0; 232 state->initialized = 1; 233 /* 234 * ssh_packet_send2() needs to queue packets until 235 * we've done the initial key exchange. 236 */ 237 state->rekeying = 1; 238 ssh->state = state; 239 return ssh; 240 fail: 241 if (state) { 242 sshbuf_free(state->input); 243 sshbuf_free(state->output); 244 sshbuf_free(state->incoming_packet); 245 sshbuf_free(state->outgoing_packet); 246 free(state); 247 } 248 free(ssh); 249 return NULL; 250} 251 252void 253ssh_packet_set_input_hook(struct ssh *ssh, ssh_packet_hook_fn *hook, void *ctx) 254{ 255 ssh->state->hook_in = hook; 256 ssh->state->hook_in_ctx = ctx; 257} 258 259/* Returns nonzero if rekeying is in progress */ 260int 261ssh_packet_is_rekeying(struct ssh *ssh) 262{ 263 return ssh->state->rekeying || 264 (ssh->kex != NULL && ssh->kex->done == 0); 265} 266 267/* 268 * Sets the descriptors used for communication. 269 */ 270struct ssh * 271ssh_packet_set_connection(struct ssh *ssh, int fd_in, int fd_out) 272{ 273 struct session_state *state; 274 const struct sshcipher *none = cipher_by_name("none"); 275 int r; 276 277 if (none == NULL) { 278 error("%s: cannot load cipher 'none'", __func__); 279 return NULL; 280 } 281 if (ssh == NULL) 282 ssh = ssh_alloc_session_state(); 283 if (ssh == NULL) { 284 error("%s: cound not allocate state", __func__); 285 return NULL; 286 } 287 state = ssh->state; 288 state->connection_in = fd_in; 289 state->connection_out = fd_out; 290 if ((r = cipher_init(&state->send_context, none, 291 (const u_char *)"", 0, NULL, 0, CIPHER_ENCRYPT)) != 0 || 292 (r = cipher_init(&state->receive_context, none, 293 (const u_char *)"", 0, NULL, 0, CIPHER_DECRYPT)) != 0) { 294 error("%s: cipher_init failed: %s", __func__, ssh_err(r)); 295 free(ssh); /* XXX need ssh_free_session_state? */ 296 return NULL; 297 } 298 state->newkeys[MODE_IN] = state->newkeys[MODE_OUT] = NULL; 299 /* 300 * Cache the IP address of the remote connection for use in error 301 * messages that might be generated after the connection has closed. 302 */ 303 (void)ssh_remote_ipaddr(ssh); 304 return ssh; 305} 306 307void 308ssh_packet_set_timeout(struct ssh *ssh, int timeout, int count) 309{ 310 struct session_state *state = ssh->state; 311 312 if (timeout <= 0 || count <= 0) { 313 state->packet_timeout_ms = -1; 314 return; 315 } 316 if ((INT_MAX / 1000) / count < timeout) 317 state->packet_timeout_ms = INT_MAX; 318 else 319 state->packet_timeout_ms = timeout * count * 1000; 320} 321 322void 323ssh_packet_set_mux(struct ssh *ssh) 324{ 325 ssh->state->mux = 1; 326 ssh->state->rekeying = 0; 327} 328 329int 330ssh_packet_get_mux(struct ssh *ssh) 331{ 332 return ssh->state->mux; 333} 334 335int 336ssh_packet_set_log_preamble(struct ssh *ssh, const char *fmt, ...) 337{ 338 va_list args; 339 int r; 340 341 free(ssh->log_preamble); 342 if (fmt == NULL) 343 ssh->log_preamble = NULL; 344 else { 345 va_start(args, fmt); 346 r = vasprintf(&ssh->log_preamble, fmt, args); 347 va_end(args); 348 if (r < 0 || ssh->log_preamble == NULL) 349 return SSH_ERR_ALLOC_FAIL; 350 } 351 return 0; 352} 353 354int 355ssh_packet_stop_discard(struct ssh *ssh) 356{ 357 struct session_state *state = ssh->state; 358 int r; 359 360 if (state->packet_discard_mac) { 361 char buf[1024]; 362 size_t dlen = PACKET_MAX_SIZE; 363 364 if (dlen > state->packet_discard_mac_already) 365 dlen -= state->packet_discard_mac_already; 366 memset(buf, 'a', sizeof(buf)); 367 while (sshbuf_len(state->incoming_packet) < dlen) 368 if ((r = sshbuf_put(state->incoming_packet, buf, 369 sizeof(buf))) != 0) 370 return r; 371 (void) mac_compute(state->packet_discard_mac, 372 state->p_read.seqnr, 373 sshbuf_ptr(state->incoming_packet), dlen, 374 NULL, 0); 375 } 376 logit("Finished discarding for %.200s port %d", 377 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 378 return SSH_ERR_MAC_INVALID; 379} 380 381static int 382ssh_packet_start_discard(struct ssh *ssh, struct sshenc *enc, 383 struct sshmac *mac, size_t mac_already, u_int discard) 384{ 385 struct session_state *state = ssh->state; 386 int r; 387 388 if (enc == NULL || !cipher_is_cbc(enc->cipher) || (mac && mac->etm)) { 389 if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0) 390 return r; 391 return SSH_ERR_MAC_INVALID; 392 } 393 /* 394 * Record number of bytes over which the mac has already 395 * been computed in order to minimize timing attacks. 396 */ 397 if (mac && mac->enabled) { 398 state->packet_discard_mac = mac; 399 state->packet_discard_mac_already = mac_already; 400 } 401 if (sshbuf_len(state->input) >= discard) 402 return ssh_packet_stop_discard(ssh); 403 state->packet_discard = discard - sshbuf_len(state->input); 404 return 0; 405} 406 407/* Returns 1 if remote host is connected via socket, 0 if not. */ 408 409int 410ssh_packet_connection_is_on_socket(struct ssh *ssh) 411{ 412 struct session_state *state; 413 struct sockaddr_storage from, to; 414 socklen_t fromlen, tolen; 415 416 if (ssh == NULL || ssh->state == NULL) 417 return 0; 418 419 state = ssh->state; 420 if (state->connection_in == -1 || state->connection_out == -1) 421 return 0; 422 /* filedescriptors in and out are the same, so it's a socket */ 423 if (state->connection_in == state->connection_out) 424 return 1; 425 fromlen = sizeof(from); 426 memset(&from, 0, sizeof(from)); 427 if (getpeername(state->connection_in, (struct sockaddr *)&from, 428 &fromlen) < 0) 429 return 0; 430 tolen = sizeof(to); 431 memset(&to, 0, sizeof(to)); 432 if (getpeername(state->connection_out, (struct sockaddr *)&to, 433 &tolen) < 0) 434 return 0; 435 if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0) 436 return 0; 437 if (from.ss_family != AF_INET && from.ss_family != AF_INET6) 438 return 0; 439 return 1; 440} 441 442void 443ssh_packet_get_bytes(struct ssh *ssh, u_int64_t *ibytes, u_int64_t *obytes) 444{ 445 if (ibytes) 446 *ibytes = ssh->state->p_read.bytes; 447 if (obytes) 448 *obytes = ssh->state->p_send.bytes; 449} 450 451int 452ssh_packet_connection_af(struct ssh *ssh) 453{ 454 struct sockaddr_storage to; 455 socklen_t tolen = sizeof(to); 456 457 memset(&to, 0, sizeof(to)); 458 if (getsockname(ssh->state->connection_out, (struct sockaddr *)&to, 459 &tolen) < 0) 460 return 0; 461 return to.ss_family; 462} 463 464/* Sets the connection into non-blocking mode. */ 465 466void 467ssh_packet_set_nonblocking(struct ssh *ssh) 468{ 469 /* Set the socket into non-blocking mode. */ 470 set_nonblock(ssh->state->connection_in); 471 472 if (ssh->state->connection_out != ssh->state->connection_in) 473 set_nonblock(ssh->state->connection_out); 474} 475 476/* Returns the socket used for reading. */ 477 478int 479ssh_packet_get_connection_in(struct ssh *ssh) 480{ 481 return ssh->state->connection_in; 482} 483 484/* Returns the descriptor used for writing. */ 485 486int 487ssh_packet_get_connection_out(struct ssh *ssh) 488{ 489 return ssh->state->connection_out; 490} 491 492/* 493 * Returns the IP-address of the remote host as a string. The returned 494 * string must not be freed. 495 */ 496 497const char * 498ssh_remote_ipaddr(struct ssh *ssh) 499{ 500 int sock; 501 502 /* Check whether we have cached the ipaddr. */ 503 if (ssh->remote_ipaddr == NULL) { 504 if (ssh_packet_connection_is_on_socket(ssh)) { 505 sock = ssh->state->connection_in; 506 ssh->remote_ipaddr = get_peer_ipaddr(sock); 507 ssh->remote_port = get_peer_port(sock); 508 ssh->local_ipaddr = get_local_ipaddr(sock); 509 ssh->local_port = get_local_port(sock); 510 } else { 511 ssh->remote_ipaddr = strdup("UNKNOWN"); 512 ssh->remote_port = 65535; 513 ssh->local_ipaddr = strdup("UNKNOWN"); 514 ssh->local_port = 65535; 515 } 516 } 517 return ssh->remote_ipaddr; 518} 519 520/* Returns the port number of the remote host. */ 521 522int 523ssh_remote_port(struct ssh *ssh) 524{ 525 (void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */ 526 return ssh->remote_port; 527} 528 529/* 530 * Returns the IP-address of the local host as a string. The returned 531 * string must not be freed. 532 */ 533 534const char * 535ssh_local_ipaddr(struct ssh *ssh) 536{ 537 (void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */ 538 return ssh->local_ipaddr; 539} 540 541/* Returns the port number of the local host. */ 542 543int 544ssh_local_port(struct ssh *ssh) 545{ 546 (void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */ 547 return ssh->local_port; 548} 549 550/* Returns the routing domain of the input socket, or NULL if unavailable */ 551const char * 552ssh_packet_rdomain_in(struct ssh *ssh) 553{ 554 if (ssh->rdomain_in != NULL) 555 return ssh->rdomain_in; 556 if (!ssh_packet_connection_is_on_socket(ssh)) 557 return NULL; 558 ssh->rdomain_in = get_rdomain(ssh->state->connection_in); 559 return ssh->rdomain_in; 560} 561 562/* Closes the connection and clears and frees internal data structures. */ 563 564static void 565ssh_packet_close_internal(struct ssh *ssh, int do_close) 566{ 567 struct session_state *state = ssh->state; 568 u_int mode; 569 570 if (!state->initialized) 571 return; 572 state->initialized = 0; 573 if (do_close) { 574 if (state->connection_in == state->connection_out) { 575 close(state->connection_out); 576 } else { 577 close(state->connection_in); 578 close(state->connection_out); 579 } 580 } 581 sshbuf_free(state->input); 582 sshbuf_free(state->output); 583 sshbuf_free(state->outgoing_packet); 584 sshbuf_free(state->incoming_packet); 585 for (mode = 0; mode < MODE_MAX; mode++) { 586 kex_free_newkeys(state->newkeys[mode]); /* current keys */ 587 state->newkeys[mode] = NULL; 588 ssh_clear_newkeys(ssh, mode); /* next keys */ 589 } 590 /* comression state is in shared mem, so we can only release it once */ 591 if (do_close && state->compression_buffer) { 592 sshbuf_free(state->compression_buffer); 593 if (state->compression_out_started) { 594 z_streamp stream = &state->compression_out_stream; 595 debug("compress outgoing: " 596 "raw data %llu, compressed %llu, factor %.2f", 597 (unsigned long long)stream->total_in, 598 (unsigned long long)stream->total_out, 599 stream->total_in == 0 ? 0.0 : 600 (double) stream->total_out / stream->total_in); 601 if (state->compression_out_failures == 0) 602 deflateEnd(stream); 603 } 604 if (state->compression_in_started) { 605 z_streamp stream = &state->compression_in_stream; 606 debug("compress incoming: " 607 "raw data %llu, compressed %llu, factor %.2f", 608 (unsigned long long)stream->total_out, 609 (unsigned long long)stream->total_in, 610 stream->total_out == 0 ? 0.0 : 611 (double) stream->total_in / stream->total_out); 612 if (state->compression_in_failures == 0) 613 inflateEnd(stream); 614 } 615 } 616 cipher_free(state->send_context); 617 cipher_free(state->receive_context); 618 state->send_context = state->receive_context = NULL; 619 if (do_close) { 620 free(ssh->local_ipaddr); 621 ssh->local_ipaddr = NULL; 622 free(ssh->remote_ipaddr); 623 ssh->remote_ipaddr = NULL; 624 free(ssh->state); 625 ssh->state = NULL; 626 } 627} 628 629void 630ssh_packet_close(struct ssh *ssh) 631{ 632 ssh_packet_close_internal(ssh, 1); 633} 634 635void 636ssh_packet_clear_keys(struct ssh *ssh) 637{ 638 ssh_packet_close_internal(ssh, 0); 639} 640 641/* Sets remote side protocol flags. */ 642 643void 644ssh_packet_set_protocol_flags(struct ssh *ssh, u_int protocol_flags) 645{ 646 ssh->state->remote_protocol_flags = protocol_flags; 647} 648 649/* Returns the remote protocol flags set earlier by the above function. */ 650 651u_int 652ssh_packet_get_protocol_flags(struct ssh *ssh) 653{ 654 return ssh->state->remote_protocol_flags; 655} 656 657/* 658 * Starts packet compression from the next packet on in both directions. 659 * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip. 660 */ 661 662static int 663ssh_packet_init_compression(struct ssh *ssh) 664{ 665 if (!ssh->state->compression_buffer && 666 ((ssh->state->compression_buffer = sshbuf_new()) == NULL)) 667 return SSH_ERR_ALLOC_FAIL; 668 return 0; 669} 670 671static int 672start_compression_out(struct ssh *ssh, int level) 673{ 674 if (level < 1 || level > 9) 675 return SSH_ERR_INVALID_ARGUMENT; 676 debug("Enabling compression at level %d.", level); 677 if (ssh->state->compression_out_started == 1) 678 deflateEnd(&ssh->state->compression_out_stream); 679 switch (deflateInit(&ssh->state->compression_out_stream, level)) { 680 case Z_OK: 681 ssh->state->compression_out_started = 1; 682 break; 683 case Z_MEM_ERROR: 684 return SSH_ERR_ALLOC_FAIL; 685 default: 686 return SSH_ERR_INTERNAL_ERROR; 687 } 688 return 0; 689} 690 691static int 692start_compression_in(struct ssh *ssh) 693{ 694 if (ssh->state->compression_in_started == 1) 695 inflateEnd(&ssh->state->compression_in_stream); 696 switch (inflateInit(&ssh->state->compression_in_stream)) { 697 case Z_OK: 698 ssh->state->compression_in_started = 1; 699 break; 700 case Z_MEM_ERROR: 701 return SSH_ERR_ALLOC_FAIL; 702 default: 703 return SSH_ERR_INTERNAL_ERROR; 704 } 705 return 0; 706} 707 708/* XXX remove need for separate compression buffer */ 709static int 710compress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out) 711{ 712 u_char buf[4096]; 713 int r, status; 714 715 if (ssh->state->compression_out_started != 1) 716 return SSH_ERR_INTERNAL_ERROR; 717 718 /* This case is not handled below. */ 719 if (sshbuf_len(in) == 0) 720 return 0; 721 722 /* Input is the contents of the input buffer. */ 723 if ((ssh->state->compression_out_stream.next_in = 724 sshbuf_mutable_ptr(in)) == NULL) 725 return SSH_ERR_INTERNAL_ERROR; 726 ssh->state->compression_out_stream.avail_in = sshbuf_len(in); 727 728 /* Loop compressing until deflate() returns with avail_out != 0. */ 729 do { 730 /* Set up fixed-size output buffer. */ 731 ssh->state->compression_out_stream.next_out = buf; 732 ssh->state->compression_out_stream.avail_out = sizeof(buf); 733 734 /* Compress as much data into the buffer as possible. */ 735 status = deflate(&ssh->state->compression_out_stream, 736 Z_PARTIAL_FLUSH); 737 switch (status) { 738 case Z_MEM_ERROR: 739 return SSH_ERR_ALLOC_FAIL; 740 case Z_OK: 741 /* Append compressed data to output_buffer. */ 742 if ((r = sshbuf_put(out, buf, sizeof(buf) - 743 ssh->state->compression_out_stream.avail_out)) != 0) 744 return r; 745 break; 746 case Z_STREAM_ERROR: 747 default: 748 ssh->state->compression_out_failures++; 749 return SSH_ERR_INVALID_FORMAT; 750 } 751 } while (ssh->state->compression_out_stream.avail_out == 0); 752 return 0; 753} 754 755static int 756uncompress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out) 757{ 758 u_char buf[4096]; 759 int r, status; 760 761 if (ssh->state->compression_in_started != 1) 762 return SSH_ERR_INTERNAL_ERROR; 763 764 if ((ssh->state->compression_in_stream.next_in = 765 sshbuf_mutable_ptr(in)) == NULL) 766 return SSH_ERR_INTERNAL_ERROR; 767 ssh->state->compression_in_stream.avail_in = sshbuf_len(in); 768 769 for (;;) { 770 /* Set up fixed-size output buffer. */ 771 ssh->state->compression_in_stream.next_out = buf; 772 ssh->state->compression_in_stream.avail_out = sizeof(buf); 773 774 status = inflate(&ssh->state->compression_in_stream, 775 Z_PARTIAL_FLUSH); 776 switch (status) { 777 case Z_OK: 778 if ((r = sshbuf_put(out, buf, sizeof(buf) - 779 ssh->state->compression_in_stream.avail_out)) != 0) 780 return r; 781 break; 782 case Z_BUF_ERROR: 783 /* 784 * Comments in zlib.h say that we should keep calling 785 * inflate() until we get an error. This appears to 786 * be the error that we get. 787 */ 788 return 0; 789 case Z_DATA_ERROR: 790 return SSH_ERR_INVALID_FORMAT; 791 case Z_MEM_ERROR: 792 return SSH_ERR_ALLOC_FAIL; 793 case Z_STREAM_ERROR: 794 default: 795 ssh->state->compression_in_failures++; 796 return SSH_ERR_INTERNAL_ERROR; 797 } 798 } 799 /* NOTREACHED */ 800} 801 802void 803ssh_clear_newkeys(struct ssh *ssh, int mode) 804{ 805 if (ssh->kex && ssh->kex->newkeys[mode]) { 806 kex_free_newkeys(ssh->kex->newkeys[mode]); 807 ssh->kex->newkeys[mode] = NULL; 808 } 809} 810 811int 812ssh_set_newkeys(struct ssh *ssh, int mode) 813{ 814 struct session_state *state = ssh->state; 815 struct sshenc *enc; 816 struct sshmac *mac; 817 struct sshcomp *comp; 818 struct sshcipher_ctx **ccp; 819 struct packet_state *ps; 820 u_int64_t *max_blocks; 821 const char *wmsg; 822 int r, crypt_type; 823 824 debug2("set_newkeys: mode %d", mode); 825 826 if (mode == MODE_OUT) { 827 ccp = &state->send_context; 828 crypt_type = CIPHER_ENCRYPT; 829 ps = &state->p_send; 830 max_blocks = &state->max_blocks_out; 831 } else { 832 ccp = &state->receive_context; 833 crypt_type = CIPHER_DECRYPT; 834 ps = &state->p_read; 835 max_blocks = &state->max_blocks_in; 836 } 837 if (state->newkeys[mode] != NULL) { 838 debug("set_newkeys: rekeying, input %llu bytes %llu blocks, " 839 "output %llu bytes %llu blocks", 840 (unsigned long long)state->p_read.bytes, 841 (unsigned long long)state->p_read.blocks, 842 (unsigned long long)state->p_send.bytes, 843 (unsigned long long)state->p_send.blocks); 844 cipher_free(*ccp); 845 *ccp = NULL; 846 kex_free_newkeys(state->newkeys[mode]); 847 state->newkeys[mode] = NULL; 848 } 849 /* note that both bytes and the seqnr are not reset */ 850 ps->packets = ps->blocks = 0; 851 /* move newkeys from kex to state */ 852 if ((state->newkeys[mode] = ssh->kex->newkeys[mode]) == NULL) 853 return SSH_ERR_INTERNAL_ERROR; 854 ssh->kex->newkeys[mode] = NULL; 855 enc = &state->newkeys[mode]->enc; 856 mac = &state->newkeys[mode]->mac; 857 comp = &state->newkeys[mode]->comp; 858 if (cipher_authlen(enc->cipher) == 0) { 859 if ((r = mac_init(mac)) != 0) 860 return r; 861 } 862 mac->enabled = 1; 863 DBG(debug("cipher_init_context: %d", mode)); 864 if ((r = cipher_init(ccp, enc->cipher, enc->key, enc->key_len, 865 enc->iv, enc->iv_len, crypt_type)) != 0) 866 return r; 867 if (!state->cipher_warning_done && 868 (wmsg = cipher_warning_message(*ccp)) != NULL) { 869 error("Warning: %s", wmsg); 870 state->cipher_warning_done = 1; 871 } 872 /* Deleting the keys does not gain extra security */ 873 /* explicit_bzero(enc->iv, enc->block_size); 874 explicit_bzero(enc->key, enc->key_len); 875 explicit_bzero(mac->key, mac->key_len); */ 876 if ((comp->type == COMP_ZLIB || 877 (comp->type == COMP_DELAYED && 878 state->after_authentication)) && comp->enabled == 0) { 879 if ((r = ssh_packet_init_compression(ssh)) < 0) 880 return r; 881 if (mode == MODE_OUT) { 882 if ((r = start_compression_out(ssh, 6)) != 0) 883 return r; 884 } else { 885 if ((r = start_compression_in(ssh)) != 0) 886 return r; 887 } 888 comp->enabled = 1; 889 } 890 /* 891 * The 2^(blocksize*2) limit is too expensive for 3DES, 892 * so enforce a 1GB limit for small blocksizes. 893 * See RFC4344 section 3.2. 894 */ 895 if (enc->block_size >= 16) 896 *max_blocks = (u_int64_t)1 << (enc->block_size*2); 897 else 898 *max_blocks = ((u_int64_t)1 << 30) / enc->block_size; 899 if (state->rekey_limit) 900 *max_blocks = MINIMUM(*max_blocks, 901 state->rekey_limit / enc->block_size); 902 debug("rekey after %llu blocks", (unsigned long long)*max_blocks); 903 return 0; 904} 905 906#define MAX_PACKETS (1U<<31) 907static int 908ssh_packet_need_rekeying(struct ssh *ssh, u_int outbound_packet_len) 909{ 910 struct session_state *state = ssh->state; 911 u_int32_t out_blocks; 912 913 /* XXX client can't cope with rekeying pre-auth */ 914 if (!state->after_authentication) 915 return 0; 916 917 /* Haven't keyed yet or KEX in progress. */ 918 if (ssh->kex == NULL || ssh_packet_is_rekeying(ssh)) 919 return 0; 920 921 /* Peer can't rekey */ 922 if (ssh->compat & SSH_BUG_NOREKEY) 923 return 0; 924 925 /* 926 * Permit one packet in or out per rekey - this allows us to 927 * make progress when rekey limits are very small. 928 */ 929 if (state->p_send.packets == 0 && state->p_read.packets == 0) 930 return 0; 931 932 /* Time-based rekeying */ 933 if (state->rekey_interval != 0 && 934 (int64_t)state->rekey_time + state->rekey_interval <= monotime()) 935 return 1; 936 937 /* 938 * Always rekey when MAX_PACKETS sent in either direction 939 * As per RFC4344 section 3.1 we do this after 2^31 packets. 940 */ 941 if (state->p_send.packets > MAX_PACKETS || 942 state->p_read.packets > MAX_PACKETS) 943 return 1; 944 945 /* Rekey after (cipher-specific) maxiumum blocks */ 946 out_blocks = ROUNDUP(outbound_packet_len, 947 state->newkeys[MODE_OUT]->enc.block_size); 948 return (state->max_blocks_out && 949 (state->p_send.blocks + out_blocks > state->max_blocks_out)) || 950 (state->max_blocks_in && 951 (state->p_read.blocks > state->max_blocks_in)); 952} 953 954/* 955 * Delayed compression for SSH2 is enabled after authentication: 956 * This happens on the server side after a SSH2_MSG_USERAUTH_SUCCESS is sent, 957 * and on the client side after a SSH2_MSG_USERAUTH_SUCCESS is received. 958 */ 959static int 960ssh_packet_enable_delayed_compress(struct ssh *ssh) 961{ 962 struct session_state *state = ssh->state; 963 struct sshcomp *comp = NULL; 964 int r, mode; 965 966 /* 967 * Remember that we are past the authentication step, so rekeying 968 * with COMP_DELAYED will turn on compression immediately. 969 */ 970 state->after_authentication = 1; 971 for (mode = 0; mode < MODE_MAX; mode++) { 972 /* protocol error: USERAUTH_SUCCESS received before NEWKEYS */ 973 if (state->newkeys[mode] == NULL) 974 continue; 975 comp = &state->newkeys[mode]->comp; 976 if (comp && !comp->enabled && comp->type == COMP_DELAYED) { 977 if ((r = ssh_packet_init_compression(ssh)) != 0) 978 return r; 979 if (mode == MODE_OUT) { 980 if ((r = start_compression_out(ssh, 6)) != 0) 981 return r; 982 } else { 983 if ((r = start_compression_in(ssh)) != 0) 984 return r; 985 } 986 comp->enabled = 1; 987 } 988 } 989 return 0; 990} 991 992/* Used to mute debug logging for noisy packet types */ 993int 994ssh_packet_log_type(u_char type) 995{ 996 switch (type) { 997 case SSH2_MSG_CHANNEL_DATA: 998 case SSH2_MSG_CHANNEL_EXTENDED_DATA: 999 case SSH2_MSG_CHANNEL_WINDOW_ADJUST: 1000 return 0; 1001 default: 1002 return 1; 1003 } 1004} 1005 1006/* 1007 * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue) 1008 */ 1009int 1010ssh_packet_send2_wrapped(struct ssh *ssh) 1011{ 1012 struct session_state *state = ssh->state; 1013 u_char type, *cp, macbuf[SSH_DIGEST_MAX_LENGTH]; 1014 u_char tmp, padlen, pad = 0; 1015 u_int authlen = 0, aadlen = 0; 1016 u_int len; 1017 struct sshenc *enc = NULL; 1018 struct sshmac *mac = NULL; 1019 struct sshcomp *comp = NULL; 1020 int r, block_size; 1021 1022 if (state->newkeys[MODE_OUT] != NULL) { 1023 enc = &state->newkeys[MODE_OUT]->enc; 1024 mac = &state->newkeys[MODE_OUT]->mac; 1025 comp = &state->newkeys[MODE_OUT]->comp; 1026 /* disable mac for authenticated encryption */ 1027 if ((authlen = cipher_authlen(enc->cipher)) != 0) 1028 mac = NULL; 1029 } 1030 block_size = enc ? enc->block_size : 8; 1031 aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0; 1032 1033 type = (sshbuf_ptr(state->outgoing_packet))[5]; 1034 if (ssh_packet_log_type(type)) 1035 debug3("send packet: type %u", type); 1036#ifdef PACKET_DEBUG 1037 fprintf(stderr, "plain: "); 1038 sshbuf_dump(state->outgoing_packet, stderr); 1039#endif 1040 1041 if (comp && comp->enabled) { 1042 len = sshbuf_len(state->outgoing_packet); 1043 /* skip header, compress only payload */ 1044 if ((r = sshbuf_consume(state->outgoing_packet, 5)) != 0) 1045 goto out; 1046 sshbuf_reset(state->compression_buffer); 1047 if ((r = compress_buffer(ssh, state->outgoing_packet, 1048 state->compression_buffer)) != 0) 1049 goto out; 1050 sshbuf_reset(state->outgoing_packet); 1051 if ((r = sshbuf_put(state->outgoing_packet, 1052 "\0\0\0\0\0", 5)) != 0 || 1053 (r = sshbuf_putb(state->outgoing_packet, 1054 state->compression_buffer)) != 0) 1055 goto out; 1056 DBG(debug("compression: raw %d compressed %zd", len, 1057 sshbuf_len(state->outgoing_packet))); 1058 } 1059 1060 /* sizeof (packet_len + pad_len + payload) */ 1061 len = sshbuf_len(state->outgoing_packet); 1062 1063 /* 1064 * calc size of padding, alloc space, get random data, 1065 * minimum padding is 4 bytes 1066 */ 1067 len -= aadlen; /* packet length is not encrypted for EtM modes */ 1068 padlen = block_size - (len % block_size); 1069 if (padlen < 4) 1070 padlen += block_size; 1071 if (state->extra_pad) { 1072 tmp = state->extra_pad; 1073 state->extra_pad = 1074 ROUNDUP(state->extra_pad, block_size); 1075 /* check if roundup overflowed */ 1076 if (state->extra_pad < tmp) 1077 return SSH_ERR_INVALID_ARGUMENT; 1078 tmp = (len + padlen) % state->extra_pad; 1079 /* Check whether pad calculation below will underflow */ 1080 if (tmp > state->extra_pad) 1081 return SSH_ERR_INVALID_ARGUMENT; 1082 pad = state->extra_pad - tmp; 1083 DBG(debug3("%s: adding %d (len %d padlen %d extra_pad %d)", 1084 __func__, pad, len, padlen, state->extra_pad)); 1085 tmp = padlen; 1086 padlen += pad; 1087 /* Check whether padlen calculation overflowed */ 1088 if (padlen < tmp) 1089 return SSH_ERR_INVALID_ARGUMENT; /* overflow */ 1090 state->extra_pad = 0; 1091 } 1092 if ((r = sshbuf_reserve(state->outgoing_packet, padlen, &cp)) != 0) 1093 goto out; 1094 if (enc && !cipher_ctx_is_plaintext(state->send_context)) { 1095 /* random padding */ 1096 arc4random_buf(cp, padlen); 1097 } else { 1098 /* clear padding */ 1099 explicit_bzero(cp, padlen); 1100 } 1101 /* sizeof (packet_len + pad_len + payload + padding) */ 1102 len = sshbuf_len(state->outgoing_packet); 1103 cp = sshbuf_mutable_ptr(state->outgoing_packet); 1104 if (cp == NULL) { 1105 r = SSH_ERR_INTERNAL_ERROR; 1106 goto out; 1107 } 1108 /* packet_length includes payload, padding and padding length field */ 1109 POKE_U32(cp, len - 4); 1110 cp[4] = padlen; 1111 DBG(debug("send: len %d (includes padlen %d, aadlen %d)", 1112 len, padlen, aadlen)); 1113 1114 /* compute MAC over seqnr and packet(length fields, payload, padding) */ 1115debug2("mac %p, %d %d", mac, mac? mac->enabled : -1, mac ? mac->etm : -1); 1116 if (mac && mac->enabled && !mac->etm) { 1117 if ((r = mac_compute(mac, state->p_send.seqnr, 1118 sshbuf_ptr(state->outgoing_packet), len, 1119 macbuf, sizeof(macbuf))) != 0) 1120 goto out; 1121 DBG(debug("done calc MAC out #%d", state->p_send.seqnr)); 1122 } 1123 /* encrypt packet and append to output buffer. */ 1124 if ((r = sshbuf_reserve(state->output, 1125 sshbuf_len(state->outgoing_packet) + authlen, &cp)) != 0) 1126 goto out; 1127 if ((r = cipher_crypt(state->send_context, state->p_send.seqnr, cp, 1128 sshbuf_ptr(state->outgoing_packet), 1129 len - aadlen, aadlen, authlen)) != 0) 1130 goto out; 1131 /* append unencrypted MAC */ 1132 if (mac && mac->enabled) { 1133 if (mac->etm) { 1134 /* EtM: compute mac over aadlen + cipher text */ 1135 if ((r = mac_compute(mac, state->p_send.seqnr, 1136 cp, len, macbuf, sizeof(macbuf))) != 0) 1137 goto out; 1138 DBG(debug("done calc MAC(EtM) out #%d", 1139 state->p_send.seqnr)); 1140 } 1141 if ((r = sshbuf_put(state->output, macbuf, mac->mac_len)) != 0) 1142 goto out; 1143 } 1144#ifdef PACKET_DEBUG 1145 fprintf(stderr, "encrypted: "); 1146 sshbuf_dump(state->output, stderr); 1147#endif 1148 /* increment sequence number for outgoing packets */ 1149 if (++state->p_send.seqnr == 0) 1150 logit("outgoing seqnr wraps around"); 1151 if (++state->p_send.packets == 0) 1152 if (!(ssh->compat & SSH_BUG_NOREKEY)) 1153 return SSH_ERR_NEED_REKEY; 1154 state->p_send.blocks += len / block_size; 1155 state->p_send.bytes += len; 1156 sshbuf_reset(state->outgoing_packet); 1157 1158 if (type == SSH2_MSG_NEWKEYS) 1159 r = ssh_set_newkeys(ssh, MODE_OUT); 1160 else if (type == SSH2_MSG_USERAUTH_SUCCESS && state->server_side) 1161 r = ssh_packet_enable_delayed_compress(ssh); 1162 else 1163 r = 0; 1164 out: 1165 if (r < 0) 1166 return r; 1167 else 1168 return len - 4; 1169} 1170 1171/* returns non-zero if the specified packet type is usec by KEX */ 1172static int 1173ssh_packet_type_is_kex(u_char type) 1174{ 1175 return 1176 type >= SSH2_MSG_TRANSPORT_MIN && 1177 type <= SSH2_MSG_TRANSPORT_MAX && 1178 type != SSH2_MSG_SERVICE_REQUEST && 1179 type != SSH2_MSG_SERVICE_ACCEPT && 1180 type != SSH2_MSG_EXT_INFO; 1181} 1182 1183int 1184ssh_packet_send2(struct ssh *ssh) 1185{ 1186 struct session_state *state = ssh->state; 1187 struct packet *p; 1188 u_char type; 1189 int r, need_rekey; 1190 int packet_length; 1191 1192 if (sshbuf_len(state->outgoing_packet) < 6) 1193 return SSH_ERR_INTERNAL_ERROR; 1194 type = sshbuf_ptr(state->outgoing_packet)[5]; 1195 need_rekey = !ssh_packet_type_is_kex(type) && 1196 ssh_packet_need_rekeying(ssh, sshbuf_len(state->outgoing_packet)); 1197 1198 /* 1199 * During rekeying we can only send key exchange messages. 1200 * Queue everything else. 1201 */ 1202 if ((need_rekey || state->rekeying) && !ssh_packet_type_is_kex(type)) { 1203 if (need_rekey) 1204 debug3("%s: rekex triggered", __func__); 1205 debug("enqueue packet: %u", type); 1206 p = calloc(1, sizeof(*p)); 1207 if (p == NULL) 1208 return SSH_ERR_ALLOC_FAIL; 1209 p->type = type; 1210 p->payload = state->outgoing_packet; 1211 TAILQ_INSERT_TAIL(&state->outgoing, p, next); 1212 state->outgoing_packet = sshbuf_new(); 1213 if (state->outgoing_packet == NULL) 1214 return SSH_ERR_ALLOC_FAIL; 1215 if (need_rekey) { 1216 /* 1217 * This packet triggered a rekey, so send the 1218 * KEXINIT now. 1219 * NB. reenters this function via kex_start_rekex(). 1220 */ 1221 return kex_start_rekex(ssh); 1222 } 1223 return 0; 1224 } 1225 1226 /* rekeying starts with sending KEXINIT */ 1227 if (type == SSH2_MSG_KEXINIT) 1228 state->rekeying = 1; 1229 1230 if ((r = ssh_packet_send2_wrapped(ssh)) < 0) 1231 return r; 1232 1233 packet_length = r; 1234 1235 /* after a NEWKEYS message we can send the complete queue */ 1236 if (type == SSH2_MSG_NEWKEYS) { 1237 state->rekeying = 0; 1238 state->rekey_time = monotime(); 1239 while ((p = TAILQ_FIRST(&state->outgoing))) { 1240 type = p->type; 1241 /* 1242 * If this packet triggers a rekex, then skip the 1243 * remaining packets in the queue for now. 1244 * NB. re-enters this function via kex_start_rekex. 1245 */ 1246 if (ssh_packet_need_rekeying(ssh, 1247 sshbuf_len(p->payload))) { 1248 debug3("%s: queued packet triggered rekex", 1249 __func__); 1250 return kex_start_rekex(ssh); 1251 } 1252 debug("dequeue packet: %u", type); 1253 sshbuf_free(state->outgoing_packet); 1254 state->outgoing_packet = p->payload; 1255 TAILQ_REMOVE(&state->outgoing, p, next); 1256 memset(p, 0, sizeof(*p)); 1257 free(p); 1258 if ((r = ssh_packet_send2_wrapped(ssh)) < 0) 1259 return r; 1260 packet_length += r; 1261 } 1262 } 1263 return packet_length; 1264} 1265 1266/* 1267 * Waits until a packet has been received, and returns its type. Note that 1268 * no other data is processed until this returns, so this function should not 1269 * be used during the interactive session. 1270 */ 1271 1272int 1273ssh_packet_read_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1274{ 1275 struct session_state *state = ssh->state; 1276 int len, r, ms_remain = 0; 1277 fd_set *setp; 1278 char buf[8192]; 1279 struct timeval timeout, start, *timeoutp = NULL; 1280 1281 DBG(debug("packet_read()")); 1282 1283 setp = calloc(howmany(state->connection_in + 1, 1284 NFDBITS), sizeof(fd_mask)); 1285 if (setp == NULL) 1286 return SSH_ERR_ALLOC_FAIL; 1287 1288 /* 1289 * Since we are blocking, ensure that all written packets have 1290 * been sent. 1291 */ 1292 if ((r = ssh_packet_write_wait(ssh)) < 0) 1293 goto out; 1294 1295 /* Stay in the loop until we have received a complete packet. */ 1296 for (;;) { 1297 /* Try to read a packet from the buffer. */ 1298 r = ssh_packet_read_poll_seqnr(ssh, typep, seqnr_p); 1299 if (r != 0) 1300 break; 1301 /* If we got a packet, return it. */ 1302 if (*typep != SSH_MSG_NONE) 1303 break; 1304 /* 1305 * Otherwise, wait for some data to arrive, add it to the 1306 * buffer, and try again. 1307 */ 1308 memset(setp, 0, howmany(state->connection_in + 1, 1309 NFDBITS) * sizeof(fd_mask)); 1310 FD_SET(state->connection_in, setp); 1311 1312 if (state->packet_timeout_ms > 0) { 1313 ms_remain = state->packet_timeout_ms; 1314 timeoutp = &timeout; 1315 } 1316 /* Wait for some data to arrive. */ 1317 for (;;) { 1318 if (state->packet_timeout_ms != -1) { 1319 ms_to_timeval(&timeout, ms_remain); 1320 monotime_tv(&start); 1321 } 1322 if ((r = select(state->connection_in + 1, setp, 1323 NULL, NULL, timeoutp)) >= 0) 1324 break; 1325 if (errno != EAGAIN && errno != EINTR) { 1326 r = SSH_ERR_SYSTEM_ERROR; 1327 goto out; 1328 } 1329 if (state->packet_timeout_ms == -1) 1330 continue; 1331 ms_subtract_diff(&start, &ms_remain); 1332 if (ms_remain <= 0) { 1333 r = 0; 1334 break; 1335 } 1336 } 1337 if (r == 0) { 1338 r = SSH_ERR_CONN_TIMEOUT; 1339 goto out; 1340 } 1341 /* Read data from the socket. */ 1342 len = read(state->connection_in, buf, sizeof(buf)); 1343 if (len == 0) { 1344 r = SSH_ERR_CONN_CLOSED; 1345 goto out; 1346 } 1347 if (len < 0) { 1348 r = SSH_ERR_SYSTEM_ERROR; 1349 goto out; 1350 } 1351 1352 /* Append it to the buffer. */ 1353 if ((r = ssh_packet_process_incoming(ssh, buf, len)) != 0) 1354 goto out; 1355 } 1356 out: 1357 free(setp); 1358 return r; 1359} 1360 1361int 1362ssh_packet_read(struct ssh *ssh) 1363{ 1364 u_char type; 1365 int r; 1366 1367 if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0) 1368 fatal("%s: %s", __func__, ssh_err(r)); 1369 return type; 1370} 1371 1372/* 1373 * Waits until a packet has been received, verifies that its type matches 1374 * that given, and gives a fatal error and exits if there is a mismatch. 1375 */ 1376 1377int 1378ssh_packet_read_expect(struct ssh *ssh, u_int expected_type) 1379{ 1380 int r; 1381 u_char type; 1382 1383 if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0) 1384 return r; 1385 if (type != expected_type) { 1386 if ((r = sshpkt_disconnect(ssh, 1387 "Protocol error: expected packet type %d, got %d", 1388 expected_type, type)) != 0) 1389 return r; 1390 return SSH_ERR_PROTOCOL_ERROR; 1391 } 1392 return 0; 1393} 1394 1395static int 1396ssh_packet_read_poll2_mux(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1397{ 1398 struct session_state *state = ssh->state; 1399 const u_char *cp; 1400 size_t need; 1401 int r; 1402 1403 if (ssh->kex) 1404 return SSH_ERR_INTERNAL_ERROR; 1405 *typep = SSH_MSG_NONE; 1406 cp = sshbuf_ptr(state->input); 1407 if (state->packlen == 0) { 1408 if (sshbuf_len(state->input) < 4 + 1) 1409 return 0; /* packet is incomplete */ 1410 state->packlen = PEEK_U32(cp); 1411 if (state->packlen < 4 + 1 || 1412 state->packlen > PACKET_MAX_SIZE) 1413 return SSH_ERR_MESSAGE_INCOMPLETE; 1414 } 1415 need = state->packlen + 4; 1416 if (sshbuf_len(state->input) < need) 1417 return 0; /* packet is incomplete */ 1418 sshbuf_reset(state->incoming_packet); 1419 if ((r = sshbuf_put(state->incoming_packet, cp + 4, 1420 state->packlen)) != 0 || 1421 (r = sshbuf_consume(state->input, need)) != 0 || 1422 (r = sshbuf_get_u8(state->incoming_packet, NULL)) != 0 || 1423 (r = sshbuf_get_u8(state->incoming_packet, typep)) != 0) 1424 return r; 1425 if (ssh_packet_log_type(*typep)) 1426 debug3("%s: type %u", __func__, *typep); 1427 /* sshbuf_dump(state->incoming_packet, stderr); */ 1428 /* reset for next packet */ 1429 state->packlen = 0; 1430 return r; 1431} 1432 1433int 1434ssh_packet_read_poll2(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1435{ 1436 struct session_state *state = ssh->state; 1437 u_int padlen, need; 1438 u_char *cp; 1439 u_int maclen, aadlen = 0, authlen = 0, block_size; 1440 struct sshenc *enc = NULL; 1441 struct sshmac *mac = NULL; 1442 struct sshcomp *comp = NULL; 1443 int r; 1444 1445 if (state->mux) 1446 return ssh_packet_read_poll2_mux(ssh, typep, seqnr_p); 1447 1448 *typep = SSH_MSG_NONE; 1449 1450 if (state->packet_discard) 1451 return 0; 1452 1453 if (state->newkeys[MODE_IN] != NULL) { 1454 enc = &state->newkeys[MODE_IN]->enc; 1455 mac = &state->newkeys[MODE_IN]->mac; 1456 comp = &state->newkeys[MODE_IN]->comp; 1457 /* disable mac for authenticated encryption */ 1458 if ((authlen = cipher_authlen(enc->cipher)) != 0) 1459 mac = NULL; 1460 } 1461 maclen = mac && mac->enabled ? mac->mac_len : 0; 1462 block_size = enc ? enc->block_size : 8; 1463 aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0; 1464 1465 if (aadlen && state->packlen == 0) { 1466 if (cipher_get_length(state->receive_context, 1467 &state->packlen, state->p_read.seqnr, 1468 sshbuf_ptr(state->input), sshbuf_len(state->input)) != 0) 1469 return 0; 1470 if (state->packlen < 1 + 4 || 1471 state->packlen > PACKET_MAX_SIZE) { 1472#ifdef PACKET_DEBUG 1473 sshbuf_dump(state->input, stderr); 1474#endif 1475 logit("Bad packet length %u.", state->packlen); 1476 if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0) 1477 return r; 1478 return SSH_ERR_CONN_CORRUPT; 1479 } 1480 sshbuf_reset(state->incoming_packet); 1481 } else if (state->packlen == 0) { 1482 /* 1483 * check if input size is less than the cipher block size, 1484 * decrypt first block and extract length of incoming packet 1485 */ 1486 if (sshbuf_len(state->input) < block_size) 1487 return 0; 1488 sshbuf_reset(state->incoming_packet); 1489 if ((r = sshbuf_reserve(state->incoming_packet, block_size, 1490 &cp)) != 0) 1491 goto out; 1492 if ((r = cipher_crypt(state->receive_context, 1493 state->p_send.seqnr, cp, sshbuf_ptr(state->input), 1494 block_size, 0, 0)) != 0) 1495 goto out; 1496 state->packlen = PEEK_U32(sshbuf_ptr(state->incoming_packet)); 1497 if (state->packlen < 1 + 4 || 1498 state->packlen > PACKET_MAX_SIZE) { 1499#ifdef PACKET_DEBUG 1500 fprintf(stderr, "input: \n"); 1501 sshbuf_dump(state->input, stderr); 1502 fprintf(stderr, "incoming_packet: \n"); 1503 sshbuf_dump(state->incoming_packet, stderr); 1504#endif 1505 logit("Bad packet length %u.", state->packlen); 1506 return ssh_packet_start_discard(ssh, enc, mac, 0, 1507 PACKET_MAX_SIZE); 1508 } 1509 if ((r = sshbuf_consume(state->input, block_size)) != 0) 1510 goto out; 1511 } 1512 DBG(debug("input: packet len %u", state->packlen+4)); 1513 1514 if (aadlen) { 1515 /* only the payload is encrypted */ 1516 need = state->packlen; 1517 } else { 1518 /* 1519 * the payload size and the payload are encrypted, but we 1520 * have a partial packet of block_size bytes 1521 */ 1522 need = 4 + state->packlen - block_size; 1523 } 1524 DBG(debug("partial packet: block %d, need %d, maclen %d, authlen %d," 1525 " aadlen %d", block_size, need, maclen, authlen, aadlen)); 1526 if (need % block_size != 0) { 1527 logit("padding error: need %d block %d mod %d", 1528 need, block_size, need % block_size); 1529 return ssh_packet_start_discard(ssh, enc, mac, 0, 1530 PACKET_MAX_SIZE - block_size); 1531 } 1532 /* 1533 * check if the entire packet has been received and 1534 * decrypt into incoming_packet: 1535 * 'aadlen' bytes are unencrypted, but authenticated. 1536 * 'need' bytes are encrypted, followed by either 1537 * 'authlen' bytes of authentication tag or 1538 * 'maclen' bytes of message authentication code. 1539 */ 1540 if (sshbuf_len(state->input) < aadlen + need + authlen + maclen) 1541 return 0; /* packet is incomplete */ 1542#ifdef PACKET_DEBUG 1543 fprintf(stderr, "read_poll enc/full: "); 1544 sshbuf_dump(state->input, stderr); 1545#endif 1546 /* EtM: check mac over encrypted input */ 1547 if (mac && mac->enabled && mac->etm) { 1548 if ((r = mac_check(mac, state->p_read.seqnr, 1549 sshbuf_ptr(state->input), aadlen + need, 1550 sshbuf_ptr(state->input) + aadlen + need + authlen, 1551 maclen)) != 0) { 1552 if (r == SSH_ERR_MAC_INVALID) 1553 logit("Corrupted MAC on input."); 1554 goto out; 1555 } 1556 } 1557 if ((r = sshbuf_reserve(state->incoming_packet, aadlen + need, 1558 &cp)) != 0) 1559 goto out; 1560 if ((r = cipher_crypt(state->receive_context, state->p_read.seqnr, cp, 1561 sshbuf_ptr(state->input), need, aadlen, authlen)) != 0) 1562 goto out; 1563 if ((r = sshbuf_consume(state->input, aadlen + need + authlen)) != 0) 1564 goto out; 1565 if (mac && mac->enabled) { 1566 /* Not EtM: check MAC over cleartext */ 1567 if (!mac->etm && (r = mac_check(mac, state->p_read.seqnr, 1568 sshbuf_ptr(state->incoming_packet), 1569 sshbuf_len(state->incoming_packet), 1570 sshbuf_ptr(state->input), maclen)) != 0) { 1571 if (r != SSH_ERR_MAC_INVALID) 1572 goto out; 1573 logit("Corrupted MAC on input."); 1574 if (need + block_size > PACKET_MAX_SIZE) 1575 return SSH_ERR_INTERNAL_ERROR; 1576 return ssh_packet_start_discard(ssh, enc, mac, 1577 sshbuf_len(state->incoming_packet), 1578 PACKET_MAX_SIZE - need - block_size); 1579 } 1580 /* Remove MAC from input buffer */ 1581 DBG(debug("MAC #%d ok", state->p_read.seqnr)); 1582 if ((r = sshbuf_consume(state->input, mac->mac_len)) != 0) 1583 goto out; 1584 } 1585 if (seqnr_p != NULL) 1586 *seqnr_p = state->p_read.seqnr; 1587 if (++state->p_read.seqnr == 0) 1588 logit("incoming seqnr wraps around"); 1589 if (++state->p_read.packets == 0) 1590 if (!(ssh->compat & SSH_BUG_NOREKEY)) 1591 return SSH_ERR_NEED_REKEY; 1592 state->p_read.blocks += (state->packlen + 4) / block_size; 1593 state->p_read.bytes += state->packlen + 4; 1594 1595 /* get padlen */ 1596 padlen = sshbuf_ptr(state->incoming_packet)[4]; 1597 DBG(debug("input: padlen %d", padlen)); 1598 if (padlen < 4) { 1599 if ((r = sshpkt_disconnect(ssh, 1600 "Corrupted padlen %d on input.", padlen)) != 0 || 1601 (r = ssh_packet_write_wait(ssh)) < 0) 1602 return r; 1603 return SSH_ERR_CONN_CORRUPT; 1604 } 1605 1606 /* skip packet size + padlen, discard padding */ 1607 if ((r = sshbuf_consume(state->incoming_packet, 4 + 1)) != 0 || 1608 ((r = sshbuf_consume_end(state->incoming_packet, padlen)) != 0)) 1609 goto out; 1610 1611 DBG(debug("input: len before de-compress %zd", 1612 sshbuf_len(state->incoming_packet))); 1613 if (comp && comp->enabled) { 1614 sshbuf_reset(state->compression_buffer); 1615 if ((r = uncompress_buffer(ssh, state->incoming_packet, 1616 state->compression_buffer)) != 0) 1617 goto out; 1618 sshbuf_reset(state->incoming_packet); 1619 if ((r = sshbuf_putb(state->incoming_packet, 1620 state->compression_buffer)) != 0) 1621 goto out; 1622 DBG(debug("input: len after de-compress %zd", 1623 sshbuf_len(state->incoming_packet))); 1624 } 1625 /* 1626 * get packet type, implies consume. 1627 * return length of payload (without type field) 1628 */ 1629 if ((r = sshbuf_get_u8(state->incoming_packet, typep)) != 0) 1630 goto out; 1631 if (ssh_packet_log_type(*typep)) 1632 debug3("receive packet: type %u", *typep); 1633 if (*typep < SSH2_MSG_MIN || *typep >= SSH2_MSG_LOCAL_MIN) { 1634 if ((r = sshpkt_disconnect(ssh, 1635 "Invalid ssh2 packet type: %d", *typep)) != 0 || 1636 (r = ssh_packet_write_wait(ssh)) < 0) 1637 return r; 1638 return SSH_ERR_PROTOCOL_ERROR; 1639 } 1640 if (state->hook_in != NULL && 1641 (r = state->hook_in(ssh, state->incoming_packet, typep, 1642 state->hook_in_ctx)) != 0) 1643 return r; 1644 if (*typep == SSH2_MSG_USERAUTH_SUCCESS && !state->server_side) 1645 r = ssh_packet_enable_delayed_compress(ssh); 1646 else 1647 r = 0; 1648#ifdef PACKET_DEBUG 1649 fprintf(stderr, "read/plain[%d]:\r\n", *typep); 1650 sshbuf_dump(state->incoming_packet, stderr); 1651#endif 1652 /* reset for next packet */ 1653 state->packlen = 0; 1654 1655 /* do we need to rekey? */ 1656 if (ssh_packet_need_rekeying(ssh, 0)) { 1657 debug3("%s: rekex triggered", __func__); 1658 if ((r = kex_start_rekex(ssh)) != 0) 1659 return r; 1660 } 1661 out: 1662 return r; 1663} 1664 1665int 1666ssh_packet_read_poll_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1667{ 1668 struct session_state *state = ssh->state; 1669 u_int reason, seqnr; 1670 int r; 1671 u_char *msg; 1672 1673 for (;;) { 1674 msg = NULL; 1675 r = ssh_packet_read_poll2(ssh, typep, seqnr_p); 1676 if (r != 0) 1677 return r; 1678 if (*typep) { 1679 state->keep_alive_timeouts = 0; 1680 DBG(debug("received packet type %d", *typep)); 1681 } 1682 switch (*typep) { 1683 case SSH2_MSG_IGNORE: 1684 debug3("Received SSH2_MSG_IGNORE"); 1685 break; 1686 case SSH2_MSG_DEBUG: 1687 if ((r = sshpkt_get_u8(ssh, NULL)) != 0 || 1688 (r = sshpkt_get_string(ssh, &msg, NULL)) != 0 || 1689 (r = sshpkt_get_string(ssh, NULL, NULL)) != 0) { 1690 free(msg); 1691 return r; 1692 } 1693 debug("Remote: %.900s", msg); 1694 free(msg); 1695 break; 1696 case SSH2_MSG_DISCONNECT: 1697 if ((r = sshpkt_get_u32(ssh, &reason)) != 0 || 1698 (r = sshpkt_get_string(ssh, &msg, NULL)) != 0) 1699 return r; 1700 /* Ignore normal client exit notifications */ 1701 do_log2(ssh->state->server_side && 1702 reason == SSH2_DISCONNECT_BY_APPLICATION ? 1703 SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_ERROR, 1704 "Received disconnect from %s port %d:" 1705 "%u: %.400s", ssh_remote_ipaddr(ssh), 1706 ssh_remote_port(ssh), reason, msg); 1707 free(msg); 1708 return SSH_ERR_DISCONNECTED; 1709 case SSH2_MSG_UNIMPLEMENTED: 1710 if ((r = sshpkt_get_u32(ssh, &seqnr)) != 0) 1711 return r; 1712 debug("Received SSH2_MSG_UNIMPLEMENTED for %u", 1713 seqnr); 1714 break; 1715 default: 1716 return 0; 1717 } 1718 } 1719} 1720 1721/* 1722 * Buffers the given amount of input characters. This is intended to be used 1723 * together with packet_read_poll. 1724 */ 1725 1726int 1727ssh_packet_process_incoming(struct ssh *ssh, const char *buf, u_int len) 1728{ 1729 struct session_state *state = ssh->state; 1730 int r; 1731 1732 if (state->packet_discard) { 1733 state->keep_alive_timeouts = 0; /* ?? */ 1734 if (len >= state->packet_discard) { 1735 if ((r = ssh_packet_stop_discard(ssh)) != 0) 1736 return r; 1737 } 1738 state->packet_discard -= len; 1739 return 0; 1740 } 1741 if ((r = sshbuf_put(ssh->state->input, buf, len)) != 0) 1742 return r; 1743 1744 return 0; 1745} 1746 1747int 1748ssh_packet_remaining(struct ssh *ssh) 1749{ 1750 return sshbuf_len(ssh->state->incoming_packet); 1751} 1752 1753/* 1754 * Sends a diagnostic message from the server to the client. This message 1755 * can be sent at any time (but not while constructing another message). The 1756 * message is printed immediately, but only if the client is being executed 1757 * in verbose mode. These messages are primarily intended to ease debugging 1758 * authentication problems. The length of the formatted message must not 1759 * exceed 1024 bytes. This will automatically call ssh_packet_write_wait. 1760 */ 1761void 1762ssh_packet_send_debug(struct ssh *ssh, const char *fmt,...) 1763{ 1764 char buf[1024]; 1765 va_list args; 1766 int r; 1767 1768 if ((ssh->compat & SSH_BUG_DEBUG)) 1769 return; 1770 1771 va_start(args, fmt); 1772 vsnprintf(buf, sizeof(buf), fmt, args); 1773 va_end(args); 1774 1775 debug3("sending debug message: %s", buf); 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 fatal("%s: %s", __func__, ssh_err(r)); 1783 if ((r = ssh_packet_write_wait(ssh)) < 0) 1784 sshpkt_fatal(ssh, __func__, r); 1785} 1786 1787void 1788sshpkt_fmt_connection_id(struct ssh *ssh, char *s, size_t l) 1789{ 1790 snprintf(s, l, "%.200s%s%s port %d", 1791 ssh->log_preamble ? ssh->log_preamble : "", 1792 ssh->log_preamble ? " " : "", 1793 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 1794} 1795 1796/* 1797 * Pretty-print connection-terminating errors and exit. 1798 */ 1799void 1800sshpkt_fatal(struct ssh *ssh, const char *tag, int r) 1801{ 1802 char remote_id[512]; 1803 1804 sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id)); 1805 1806 switch (r) { 1807 case SSH_ERR_CONN_CLOSED: 1808 ssh_packet_clear_keys(ssh); 1809 logdie("Connection closed by %s", remote_id); 1810 case SSH_ERR_CONN_TIMEOUT: 1811 ssh_packet_clear_keys(ssh); 1812 logdie("Connection %s %s timed out", 1813 ssh->state->server_side ? "from" : "to", remote_id); 1814 case SSH_ERR_DISCONNECTED: 1815 ssh_packet_clear_keys(ssh); 1816 logdie("Disconnected from %s", remote_id); 1817 case SSH_ERR_SYSTEM_ERROR: 1818 if (errno == ECONNRESET) { 1819 ssh_packet_clear_keys(ssh); 1820 logdie("Connection reset by %s", remote_id); 1821 } 1822 /* FALLTHROUGH */ 1823 case SSH_ERR_NO_CIPHER_ALG_MATCH: 1824 case SSH_ERR_NO_MAC_ALG_MATCH: 1825 case SSH_ERR_NO_COMPRESS_ALG_MATCH: 1826 case SSH_ERR_NO_KEX_ALG_MATCH: 1827 case SSH_ERR_NO_HOSTKEY_ALG_MATCH: 1828 if (ssh && ssh->kex && ssh->kex->failed_choice) { 1829 ssh_packet_clear_keys(ssh); 1830 logdie("Unable to negotiate with %s: %s. " 1831 "Their offer: %s", remote_id, ssh_err(r), 1832 ssh->kex->failed_choice); 1833 } 1834 /* FALLTHROUGH */ 1835 default: 1836 ssh_packet_clear_keys(ssh); 1837 logdie("%s%sConnection %s %s: %s", 1838 tag != NULL ? tag : "", tag != NULL ? ": " : "", 1839 ssh->state->server_side ? "from" : "to", 1840 remote_id, ssh_err(r)); 1841 } 1842} 1843 1844/* 1845 * Logs the error plus constructs and sends a disconnect packet, closes the 1846 * connection, and exits. This function never returns. The error message 1847 * should not contain a newline. The length of the formatted message must 1848 * not exceed 1024 bytes. 1849 */ 1850void 1851ssh_packet_disconnect(struct ssh *ssh, const char *fmt,...) 1852{ 1853 char buf[1024], remote_id[512]; 1854 va_list args; 1855 static int disconnecting = 0; 1856 int r; 1857 1858 if (disconnecting) /* Guard against recursive invocations. */ 1859 fatal("packet_disconnect called recursively."); 1860 disconnecting = 1; 1861 1862 /* 1863 * Format the message. Note that the caller must make sure the 1864 * message is of limited size. 1865 */ 1866 sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id)); 1867 va_start(args, fmt); 1868 vsnprintf(buf, sizeof(buf), fmt, args); 1869 va_end(args); 1870 1871 /* Display the error locally */ 1872 logit("Disconnecting %s: %.100s", remote_id, buf); 1873 1874 /* 1875 * Send the disconnect message to the other side, and wait 1876 * for it to get sent. 1877 */ 1878 if ((r = sshpkt_disconnect(ssh, "%s", buf)) != 0) 1879 sshpkt_fatal(ssh, __func__, r); 1880 1881 if ((r = ssh_packet_write_wait(ssh)) < 0) 1882 sshpkt_fatal(ssh, __func__, r); 1883 1884 /* Close the connection. */ 1885 ssh_packet_close(ssh); 1886 cleanup_exit(254); 1887} 1888 1889/* 1890 * Checks if there is any buffered output, and tries to write some of 1891 * the output. 1892 */ 1893int 1894ssh_packet_write_poll(struct ssh *ssh) 1895{ 1896 struct session_state *state = ssh->state; 1897 int len = sshbuf_len(state->output); 1898 int r; 1899 1900 if (len > 0) { 1901 len = write(state->connection_out, 1902 sshbuf_ptr(state->output), len); 1903 if (len == -1) { 1904 if (errno == EINTR || errno == EAGAIN) 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 len; 1914} 1915 1916/* 1917 * Calls packet_write_poll repeatedly until all pending output data has been 1918 * written. 1919 */ 1920int 1921ssh_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 u_int bytes_sent = 0; 1927 struct session_state *state = ssh->state; 1928 1929 setp = calloc(howmany(state->connection_out + 1, 1930 NFDBITS), sizeof(fd_mask)); 1931 if (setp == NULL) 1932 return SSH_ERR_ALLOC_FAIL; 1933 1934 if ((r = ssh_packet_write_poll(ssh)) < 0) { 1935 free(setp); 1936 return r; 1937 } 1938 bytes_sent += r; 1939 1940 while (ssh_packet_have_data_to_write(ssh)) { 1941 memset(setp, 0, howmany(state->connection_out + 1, 1942 NFDBITS) * sizeof(fd_mask)); 1943 FD_SET(state->connection_out, setp); 1944 1945 if (state->packet_timeout_ms > 0) { 1946 ms_remain = state->packet_timeout_ms; 1947 timeoutp = &timeout; 1948 } 1949 for (;;) { 1950 if (state->packet_timeout_ms != -1) { 1951 ms_to_timeval(&timeout, ms_remain); 1952 monotime_tv(&start); 1953 } 1954 if ((ret = select(state->connection_out + 1, 1955 NULL, setp, NULL, timeoutp)) >= 0) 1956 break; 1957 if (errno != EAGAIN && errno != EINTR) 1958 break; 1959 if (state->packet_timeout_ms == -1) 1960 continue; 1961 ms_subtract_diff(&start, &ms_remain); 1962 if (ms_remain <= 0) { 1963 ret = 0; 1964 break; 1965 } 1966 } 1967 if (ret == 0) { 1968 free(setp); 1969 return SSH_ERR_CONN_TIMEOUT; 1970 } 1971 if ((r = ssh_packet_write_poll(ssh)) < 0) { 1972 free(setp); 1973 return r; 1974 } 1975 bytes_sent += r; 1976 } 1977 free(setp); 1978 return bytes_sent; 1979} 1980 1981/* Returns true if there is buffered data to write to the connection. */ 1982 1983int 1984ssh_packet_have_data_to_write(struct ssh *ssh) 1985{ 1986 return sshbuf_len(ssh->state->output) != 0; 1987} 1988 1989/* Returns true if there is not too much data to write to the connection. */ 1990 1991int 1992ssh_packet_not_very_much_data_to_write(struct ssh *ssh) 1993{ 1994 if (ssh->state->interactive_mode) 1995 return sshbuf_len(ssh->state->output) < 16384; 1996 else 1997 return sshbuf_len(ssh->state->output) < 128 * 1024; 1998} 1999 2000void 2001ssh_packet_set_tos(struct ssh *ssh, int tos) 2002{ 2003 if (!ssh_packet_connection_is_on_socket(ssh) || tos == INT_MAX) 2004 return; 2005 switch (ssh_packet_connection_af(ssh)) { 2006 case AF_INET: 2007 debug3("%s: set IP_TOS 0x%02x", __func__, tos); 2008 if (setsockopt(ssh->state->connection_in, 2009 IPPROTO_IP, IP_TOS, &tos, sizeof(tos)) < 0) 2010 error("setsockopt IP_TOS %d: %.100s:", 2011 tos, strerror(errno)); 2012 break; 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 } 2021} 2022 2023/* Informs that the current session is interactive. Sets IP flags for that. */ 2024 2025void 2026ssh_packet_set_interactive(struct ssh *ssh, int interactive, int qos_interactive, int qos_bulk) 2027{ 2028 struct session_state *state = ssh->state; 2029 2030 if (state->set_interactive_called) 2031 return; 2032 state->set_interactive_called = 1; 2033 2034 /* Record that we are in interactive mode. */ 2035 state->interactive_mode = interactive; 2036 2037 /* Only set socket options if using a socket. */ 2038 if (!ssh_packet_connection_is_on_socket(ssh)) 2039 return; 2040 set_nodelay(state->connection_in); 2041 ssh_packet_set_tos(ssh, interactive ? qos_interactive : 2042 qos_bulk); 2043} 2044 2045/* Returns true if the current connection is interactive. */ 2046 2047int 2048ssh_packet_is_interactive(struct ssh *ssh) 2049{ 2050 return ssh->state->interactive_mode; 2051} 2052 2053int 2054ssh_packet_set_maxsize(struct ssh *ssh, u_int s) 2055{ 2056 struct session_state *state = ssh->state; 2057 2058 if (state->set_maxsize_called) { 2059 logit("packet_set_maxsize: called twice: old %d new %d", 2060 state->max_packet_size, s); 2061 return -1; 2062 } 2063 if (s < 4 * 1024 || s > 1024 * 1024) { 2064 logit("packet_set_maxsize: bad size %d", s); 2065 return -1; 2066 } 2067 state->set_maxsize_called = 1; 2068 debug("packet_set_maxsize: setting to %d", s); 2069 state->max_packet_size = s; 2070 return s; 2071} 2072 2073int 2074ssh_packet_inc_alive_timeouts(struct ssh *ssh) 2075{ 2076 return ++ssh->state->keep_alive_timeouts; 2077} 2078 2079void 2080ssh_packet_set_alive_timeouts(struct ssh *ssh, int ka) 2081{ 2082 ssh->state->keep_alive_timeouts = ka; 2083} 2084 2085u_int 2086ssh_packet_get_maxsize(struct ssh *ssh) 2087{ 2088 return ssh->state->max_packet_size; 2089} 2090 2091void 2092ssh_packet_set_rekey_limits(struct ssh *ssh, u_int64_t bytes, u_int32_t seconds) 2093{ 2094 debug3("rekey after %llu bytes, %u seconds", (unsigned long long)bytes, 2095 (unsigned int)seconds); 2096 ssh->state->rekey_limit = bytes; 2097 ssh->state->rekey_interval = seconds; 2098} 2099 2100time_t 2101ssh_packet_get_rekey_timeout(struct ssh *ssh) 2102{ 2103 time_t seconds; 2104 2105 seconds = ssh->state->rekey_time + ssh->state->rekey_interval - 2106 monotime(); 2107 return (seconds <= 0 ? 1 : seconds); 2108} 2109 2110void 2111ssh_packet_set_server(struct ssh *ssh) 2112{ 2113 ssh->state->server_side = 1; 2114} 2115 2116void 2117ssh_packet_set_authenticated(struct ssh *ssh) 2118{ 2119 ssh->state->after_authentication = 1; 2120} 2121 2122void * 2123ssh_packet_get_input(struct ssh *ssh) 2124{ 2125 return (void *)ssh->state->input; 2126} 2127 2128void * 2129ssh_packet_get_output(struct ssh *ssh) 2130{ 2131 return (void *)ssh->state->output; 2132} 2133 2134/* Reset after_authentication and reset compression in post-auth privsep */ 2135static int 2136ssh_packet_set_postauth(struct ssh *ssh) 2137{ 2138 int r; 2139 2140 debug("%s: called", __func__); 2141 /* This was set in net child, but is not visible in user child */ 2142 ssh->state->after_authentication = 1; 2143 ssh->state->rekeying = 0; 2144 if ((r = ssh_packet_enable_delayed_compress(ssh)) != 0) 2145 return r; 2146 return 0; 2147} 2148 2149/* Packet state (de-)serialization for privsep */ 2150 2151/* turn kex into a blob for packet state serialization */ 2152static int 2153kex_to_blob(struct sshbuf *m, struct kex *kex) 2154{ 2155 int r; 2156 2157 if ((r = sshbuf_put_string(m, kex->session_id, 2158 kex->session_id_len)) != 0 || 2159 (r = sshbuf_put_u32(m, kex->we_need)) != 0 || 2160 (r = sshbuf_put_cstring(m, kex->hostkey_alg)) != 0 || 2161 (r = sshbuf_put_u32(m, kex->hostkey_type)) != 0 || 2162 (r = sshbuf_put_u32(m, kex->hostkey_nid)) != 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 */ 2174static int 2175newkeys_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 */ 2218int 2219ssh_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 */ 2245static int 2246newkeys_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 */ 2312static int 2313kex_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_cstring(m, &kex->hostkey_alg, NULL)) != 0 || 2327 (r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_type)) != 0 || 2328 (r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_nid)) != 0 || 2329 (r = sshbuf_get_u32(m, &kex->kex_type)) != 0 || 2330 (r = sshbuf_get_stringb(m, kex->my)) != 0 || 2331 (r = sshbuf_get_stringb(m, kex->peer)) != 0 || 2332 (r = sshbuf_get_u32(m, &kex->flags)) != 0 || 2333 (r = sshbuf_get_cstring(m, &kex->client_version_string, NULL)) != 0 || 2334 (r = sshbuf_get_cstring(m, &kex->server_version_string, NULL)) != 0) 2335 goto out; 2336 kex->server = 1; 2337 kex->done = 1; 2338 r = 0; 2339 out: 2340 if (r != 0 || kexp == NULL) { 2341 if (kex != NULL) { 2342 sshbuf_free(kex->my); 2343 sshbuf_free(kex->peer); 2344 free(kex); 2345 } 2346 if (kexp != NULL) 2347 *kexp = NULL; 2348 } else { 2349 *kexp = kex; 2350 } 2351 return r; 2352} 2353 2354/* 2355 * Restore packet state from content of blob 'm' (de-serialization). 2356 * Note that 'm' will be partially consumed on parsing or any other errors. 2357 */ 2358int 2359ssh_packet_set_state(struct ssh *ssh, struct sshbuf *m) 2360{ 2361 struct session_state *state = ssh->state; 2362 const u_char *input, *output; 2363 size_t ilen, olen; 2364 int r; 2365 2366 if ((r = kex_from_blob(m, &ssh->kex)) != 0 || 2367 (r = newkeys_from_blob(m, ssh, MODE_OUT)) != 0 || 2368 (r = newkeys_from_blob(m, ssh, MODE_IN)) != 0 || 2369 (r = sshbuf_get_u64(m, &state->rekey_limit)) != 0 || 2370 (r = sshbuf_get_u32(m, &state->rekey_interval)) != 0 || 2371 (r = sshbuf_get_u32(m, &state->p_send.seqnr)) != 0 || 2372 (r = sshbuf_get_u64(m, &state->p_send.blocks)) != 0 || 2373 (r = sshbuf_get_u32(m, &state->p_send.packets)) != 0 || 2374 (r = sshbuf_get_u64(m, &state->p_send.bytes)) != 0 || 2375 (r = sshbuf_get_u32(m, &state->p_read.seqnr)) != 0 || 2376 (r = sshbuf_get_u64(m, &state->p_read.blocks)) != 0 || 2377 (r = sshbuf_get_u32(m, &state->p_read.packets)) != 0 || 2378 (r = sshbuf_get_u64(m, &state->p_read.bytes)) != 0) 2379 return r; 2380 /* 2381 * We set the time here so that in post-auth privsep slave we 2382 * count from the completion of the authentication. 2383 */ 2384 state->rekey_time = monotime(); 2385 /* XXX ssh_set_newkeys overrides p_read.packets? XXX */ 2386 if ((r = ssh_set_newkeys(ssh, MODE_IN)) != 0 || 2387 (r = ssh_set_newkeys(ssh, MODE_OUT)) != 0) 2388 return r; 2389 2390 if ((r = ssh_packet_set_postauth(ssh)) != 0) 2391 return r; 2392 2393 sshbuf_reset(state->input); 2394 sshbuf_reset(state->output); 2395 if ((r = sshbuf_get_string_direct(m, &input, &ilen)) != 0 || 2396 (r = sshbuf_get_string_direct(m, &output, &olen)) != 0 || 2397 (r = sshbuf_put(state->input, input, ilen)) != 0 || 2398 (r = sshbuf_put(state->output, output, olen)) != 0) 2399 return r; 2400 2401 if (sshbuf_len(m)) 2402 return SSH_ERR_INVALID_FORMAT; 2403 debug3("%s: done", __func__); 2404 return 0; 2405} 2406 2407/* NEW API */ 2408 2409/* put data to the outgoing packet */ 2410 2411int 2412sshpkt_put(struct ssh *ssh, const void *v, size_t len) 2413{ 2414 return sshbuf_put(ssh->state->outgoing_packet, v, len); 2415} 2416 2417int 2418sshpkt_putb(struct ssh *ssh, const struct sshbuf *b) 2419{ 2420 return sshbuf_putb(ssh->state->outgoing_packet, b); 2421} 2422 2423int 2424sshpkt_put_u8(struct ssh *ssh, u_char val) 2425{ 2426 return sshbuf_put_u8(ssh->state->outgoing_packet, val); 2427} 2428 2429int 2430sshpkt_put_u32(struct ssh *ssh, u_int32_t val) 2431{ 2432 return sshbuf_put_u32(ssh->state->outgoing_packet, val); 2433} 2434 2435int 2436sshpkt_put_u64(struct ssh *ssh, u_int64_t val) 2437{ 2438 return sshbuf_put_u64(ssh->state->outgoing_packet, val); 2439} 2440 2441int 2442sshpkt_put_string(struct ssh *ssh, const void *v, size_t len) 2443{ 2444 return sshbuf_put_string(ssh->state->outgoing_packet, v, len); 2445} 2446 2447int 2448sshpkt_put_cstring(struct ssh *ssh, const void *v) 2449{ 2450 return sshbuf_put_cstring(ssh->state->outgoing_packet, v); 2451} 2452 2453int 2454sshpkt_put_stringb(struct ssh *ssh, const struct sshbuf *v) 2455{ 2456 return sshbuf_put_stringb(ssh->state->outgoing_packet, v); 2457} 2458 2459#ifdef WITH_OPENSSL 2460int 2461sshpkt_put_ec(struct ssh *ssh, const EC_POINT *v, const EC_GROUP *g) 2462{ 2463 return sshbuf_put_ec(ssh->state->outgoing_packet, v, g); 2464} 2465 2466 2467int 2468sshpkt_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 2476int 2477sshpkt_get(struct ssh *ssh, void *valp, size_t len) 2478{ 2479 return sshbuf_get(ssh->state->incoming_packet, valp, len); 2480} 2481 2482int 2483sshpkt_get_u8(struct ssh *ssh, u_char *valp) 2484{ 2485 return sshbuf_get_u8(ssh->state->incoming_packet, valp); 2486} 2487 2488int 2489sshpkt_get_u32(struct ssh *ssh, u_int32_t *valp) 2490{ 2491 return sshbuf_get_u32(ssh->state->incoming_packet, valp); 2492} 2493 2494int 2495sshpkt_get_u64(struct ssh *ssh, u_int64_t *valp) 2496{ 2497 return sshbuf_get_u64(ssh->state->incoming_packet, valp); 2498} 2499 2500int 2501sshpkt_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 2506int 2507sshpkt_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 2512int 2513sshpkt_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 2518int 2519sshpkt_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 2525int 2526sshpkt_get_ec(struct ssh *ssh, EC_POINT *v, const EC_GROUP *g) 2527{ 2528 return sshbuf_get_ec(ssh->state->incoming_packet, v, g); 2529} 2530 2531 2532int 2533sshpkt_get_bignum2(struct ssh *ssh, BIGNUM *v) 2534{ 2535 return sshbuf_get_bignum2(ssh->state->incoming_packet, v); 2536} 2537#endif /* WITH_OPENSSL */ 2538 2539int 2540sshpkt_get_end(struct ssh *ssh) 2541{ 2542 if (sshbuf_len(ssh->state->incoming_packet) > 0) 2543 return SSH_ERR_UNEXPECTED_TRAILING_DATA; 2544 return 0; 2545} 2546 2547const u_char * 2548sshpkt_ptr(struct ssh *ssh, size_t *lenp) 2549{ 2550 if (lenp != NULL) 2551 *lenp = sshbuf_len(ssh->state->incoming_packet); 2552 return sshbuf_ptr(ssh->state->incoming_packet); 2553} 2554 2555/* start a new packet */ 2556 2557int 2558sshpkt_start(struct ssh *ssh, u_char type) 2559{ 2560 u_char buf[6]; /* u32 packet length, u8 pad len, u8 type */ 2561 2562 DBG(debug("packet_start[%d]", type)); 2563 memset(buf, 0, sizeof(buf)); 2564 buf[sizeof(buf) - 1] = type; 2565 sshbuf_reset(ssh->state->outgoing_packet); 2566 return sshbuf_put(ssh->state->outgoing_packet, buf, sizeof(buf)); 2567} 2568 2569static int 2570ssh_packet_send_mux(struct ssh *ssh) 2571{ 2572 struct session_state *state = ssh->state; 2573 u_char type, *cp; 2574 size_t len; 2575 int r; 2576 2577 if (ssh->kex) 2578 return SSH_ERR_INTERNAL_ERROR; 2579 len = sshbuf_len(state->outgoing_packet); 2580 if (len < 6) 2581 return SSH_ERR_INTERNAL_ERROR; 2582 cp = sshbuf_mutable_ptr(state->outgoing_packet); 2583 type = cp[5]; 2584 if (ssh_packet_log_type(type)) 2585 debug3("%s: type %u", __func__, type); 2586 /* drop everything, but the connection protocol */ 2587 if (type >= SSH2_MSG_CONNECTION_MIN && 2588 type <= SSH2_MSG_CONNECTION_MAX) { 2589 POKE_U32(cp, len - 4); 2590 if ((r = sshbuf_putb(state->output, 2591 state->outgoing_packet)) != 0) 2592 return r; 2593 /* sshbuf_dump(state->output, stderr); */ 2594 } 2595 sshbuf_reset(state->outgoing_packet); 2596 return 0; 2597} 2598 2599/* 2600 * 9.2. Ignored Data Message 2601 * 2602 * byte SSH_MSG_IGNORE 2603 * string data 2604 * 2605 * All implementations MUST understand (and ignore) this message at any 2606 * time (after receiving the protocol version). No implementation is 2607 * required to send them. This message can be used as an additional 2608 * protection measure against advanced traffic analysis techniques. 2609 */ 2610int 2611sshpkt_msg_ignore(struct ssh *ssh, u_int nbytes) 2612{ 2613 u_int32_t rnd = 0; 2614 int r; 2615 u_int i; 2616 2617 if ((r = sshpkt_start(ssh, SSH2_MSG_IGNORE)) != 0 || 2618 (r = sshpkt_put_u32(ssh, nbytes)) != 0) 2619 return r; 2620 for (i = 0; i < nbytes; i++) { 2621 if (i % 4 == 0) 2622 rnd = arc4random(); 2623 if ((r = sshpkt_put_u8(ssh, (u_char)rnd & 0xff)) != 0) 2624 return r; 2625 rnd >>= 8; 2626 } 2627 return 0; 2628} 2629 2630/* send it */ 2631 2632int 2633sshpkt_sendx(struct ssh *ssh) 2634{ 2635 if (ssh->state && ssh->state->mux) 2636 return ssh_packet_send_mux(ssh); 2637 return ssh_packet_send2(ssh); 2638} 2639 2640int 2641sshpkt_send(struct ssh *ssh) 2642{ 2643 int r = sshpkt_sendx(ssh); 2644 return r < 0 ? r : 0; 2645} 2646 2647int 2648sshpkt_disconnect(struct ssh *ssh, const char *fmt,...) 2649{ 2650 char buf[1024]; 2651 va_list args; 2652 int r; 2653 2654 va_start(args, fmt); 2655 vsnprintf(buf, sizeof(buf), fmt, args); 2656 va_end(args); 2657 2658 if ((r = sshpkt_start(ssh, SSH2_MSG_DISCONNECT)) != 0 || 2659 (r = sshpkt_put_u32(ssh, SSH2_DISCONNECT_PROTOCOL_ERROR)) != 0 || 2660 (r = sshpkt_put_cstring(ssh, buf)) != 0 || 2661 (r = sshpkt_put_cstring(ssh, "")) != 0 || 2662 (r = sshpkt_send(ssh)) != 0) 2663 return r; 2664 return 0; 2665} 2666 2667/* roundup current message to pad bytes */ 2668int 2669sshpkt_add_padding(struct ssh *ssh, u_char pad) 2670{ 2671 ssh->state->extra_pad = pad; 2672 return 0; 2673} 2674 2675int 2676ssh_packet_authentication_state(void) 2677{ 2678 return active_state->state->after_authentication; 2679} 2680