1 /* $NetBSD: packet.c,v 1.26 2016/12/25 00:07:47 christos Exp $ */ 2 /* $OpenBSD: packet.c,v 1.243 2016/10/11 21:47:45 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 1.26 2016/12/25 00:07:47 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 "buffer.h" /* typedefs XXX */ 67 #include "key.h" /* typedefs XXX */ 68 69 #include "xmalloc.h" 70 #include "crc32.h" 71 #include "deattack.h" 72 #include "compat.h" 73 #include "ssh1.h" 74 #include "ssh2.h" 75 #include "cipher.h" 76 #include "sshkey.h" 77 #include "kex.h" 78 #include "digest.h" 79 #include "mac.h" 80 #include "log.h" 81 #include "canohost.h" 82 #include "misc.h" 83 #include "channels.h" 84 #include "ssh.h" 85 #include "packet.h" 86 #include "ssherr.h" 87 #include "sshbuf.h" 88 89 #ifdef PACKET_DEBUG 90 #define DBG(x) x 91 #else 92 #define DBG(x) 93 #endif 94 95 #define PACKET_MAX_SIZE (256 * 1024) 96 97 struct packet_state { 98 u_int32_t seqnr; 99 u_int32_t packets; 100 u_int64_t blocks; 101 u_int64_t bytes; 102 }; 103 104 struct packet { 105 TAILQ_ENTRY(packet) next; 106 u_char type; 107 struct sshbuf *payload; 108 }; 109 110 struct session_state { 111 /* 112 * This variable contains the file descriptors used for 113 * communicating with the other side. connection_in is used for 114 * reading; connection_out for writing. These can be the same 115 * descriptor, in which case it is assumed to be a socket. 116 */ 117 int connection_in; 118 int connection_out; 119 120 /* Protocol flags for the remote side. */ 121 u_int remote_protocol_flags; 122 123 /* Encryption context for receiving data. Only used for decryption. */ 124 struct sshcipher_ctx *receive_context; 125 126 /* Encryption context for sending data. Only used for encryption. */ 127 struct sshcipher_ctx *send_context; 128 129 /* Buffer for raw input data from the socket. */ 130 struct sshbuf *input; 131 132 /* Buffer for raw output data going to the socket. */ 133 struct sshbuf *output; 134 135 /* Buffer for the partial outgoing packet being constructed. */ 136 struct sshbuf *outgoing_packet; 137 138 /* Buffer for the incoming packet currently being processed. */ 139 struct sshbuf *incoming_packet; 140 141 /* Scratch buffer for packet compression/decompression. */ 142 struct sshbuf *compression_buffer; 143 144 /* Incoming/outgoing compression dictionaries */ 145 z_stream compression_in_stream; 146 z_stream compression_out_stream; 147 int compression_in_started; 148 int compression_out_started; 149 int compression_in_failures; 150 int compression_out_failures; 151 152 /* 153 * Flag indicating whether packet compression/decompression is 154 * enabled. 155 */ 156 int packet_compression; 157 158 /* default maximum packet size */ 159 u_int max_packet_size; 160 161 /* Flag indicating whether this module has been initialized. */ 162 int initialized; 163 164 /* Set to true if the connection is interactive. */ 165 int interactive_mode; 166 167 /* Set to true if we are the server side. */ 168 int server_side; 169 170 /* Set to true if we are authenticated. */ 171 int after_authentication; 172 173 int keep_alive_timeouts; 174 175 /* The maximum time that we will wait to send or receive a packet */ 176 int packet_timeout_ms; 177 178 /* Session key information for Encryption and MAC */ 179 struct newkeys *newkeys[MODE_MAX]; 180 struct packet_state p_read, p_send; 181 182 /* Volume-based rekeying */ 183 u_int64_t max_blocks_in, max_blocks_out, rekey_limit; 184 185 /* Time-based rekeying */ 186 u_int32_t rekey_interval; /* how often in seconds */ 187 time_t rekey_time; /* time of last rekeying */ 188 189 /* Session key for protocol v1 */ 190 u_char ssh1_key[SSH_SESSION_KEY_LENGTH]; 191 u_int ssh1_keylen; 192 193 /* roundup current message to extra_pad bytes */ 194 u_char extra_pad; 195 196 /* XXX discard incoming data after MAC error */ 197 u_int packet_discard; 198 size_t packet_discard_mac_already; 199 struct sshmac *packet_discard_mac; 200 201 /* Used in packet_read_poll2() */ 202 u_int packlen; 203 204 /* Used in packet_send2 */ 205 int rekeying; 206 207 /* Used in ssh_packet_send_mux() */ 208 int mux; 209 210 /* Used in packet_set_interactive */ 211 int set_interactive_called; 212 213 /* Used in packet_set_maxsize */ 214 int set_maxsize_called; 215 216 /* One-off warning about weak ciphers */ 217 int cipher_warning_done; 218 219 /* SSH1 CRC compensation attack detector */ 220 struct deattack_ctx deattack; 221 222 /* Hook for fuzzing inbound packets */ 223 ssh_packet_hook_fn *hook_in; 224 void *hook_in_ctx; 225 226 TAILQ_HEAD(, packet) outgoing; 227 }; 228 229 struct ssh * 230 ssh_alloc_session_state(void) 231 { 232 struct ssh *ssh = NULL; 233 struct session_state *state = NULL; 234 235 if ((ssh = calloc(1, sizeof(*ssh))) == NULL || 236 (state = calloc(1, sizeof(*state))) == NULL || 237 (state->input = sshbuf_new()) == NULL || 238 (state->output = sshbuf_new()) == NULL || 239 (state->outgoing_packet = sshbuf_new()) == NULL || 240 (state->incoming_packet = sshbuf_new()) == NULL) 241 goto fail; 242 TAILQ_INIT(&state->outgoing); 243 TAILQ_INIT(&ssh->private_keys); 244 TAILQ_INIT(&ssh->public_keys); 245 state->connection_in = -1; 246 state->connection_out = -1; 247 state->max_packet_size = 32768; 248 state->packet_timeout_ms = -1; 249 state->p_send.packets = state->p_read.packets = 0; 250 state->initialized = 1; 251 /* 252 * ssh_packet_send2() needs to queue packets until 253 * we've done the initial key exchange. 254 */ 255 state->rekeying = 1; 256 ssh->state = state; 257 return ssh; 258 fail: 259 if (state) { 260 sshbuf_free(state->input); 261 sshbuf_free(state->output); 262 sshbuf_free(state->incoming_packet); 263 sshbuf_free(state->outgoing_packet); 264 free(state); 265 } 266 free(ssh); 267 return NULL; 268 } 269 270 void 271 ssh_packet_set_input_hook(struct ssh *ssh, ssh_packet_hook_fn *hook, void *ctx) 272 { 273 ssh->state->hook_in = hook; 274 ssh->state->hook_in_ctx = ctx; 275 } 276 277 /* Returns nonzero if rekeying is in progress */ 278 int 279 ssh_packet_is_rekeying(struct ssh *ssh) 280 { 281 return compat20 && 282 (ssh->state->rekeying || (ssh->kex != NULL && ssh->kex->done == 0)); 283 } 284 285 /* 286 * Sets the descriptors used for communication. Disables encryption until 287 * packet_set_encryption_key is called. 288 */ 289 struct ssh * 290 ssh_packet_set_connection(struct ssh *ssh, int fd_in, int fd_out) 291 { 292 struct session_state *state; 293 const struct sshcipher *none = cipher_by_name("none"); 294 int r; 295 296 if (none == NULL) { 297 error("%s: cannot load cipher 'none'", __func__); 298 return NULL; 299 } 300 if (ssh == NULL) 301 ssh = ssh_alloc_session_state(); 302 if (ssh == NULL) { 303 error("%s: cound not allocate state", __func__); 304 return NULL; 305 } 306 state = ssh->state; 307 state->connection_in = fd_in; 308 state->connection_out = fd_out; 309 if ((r = cipher_init(&state->send_context, none, 310 (const u_char *)"", 0, NULL, 0, CIPHER_ENCRYPT)) != 0 || 311 (r = cipher_init(&state->receive_context, none, 312 (const u_char *)"", 0, NULL, 0, CIPHER_DECRYPT)) != 0) { 313 error("%s: cipher_init failed: %s", __func__, ssh_err(r)); 314 free(ssh); /* XXX need ssh_free_session_state? */ 315 return NULL; 316 } 317 state->newkeys[MODE_IN] = state->newkeys[MODE_OUT] = NULL; 318 deattack_init(&state->deattack); 319 /* 320 * Cache the IP address of the remote connection for use in error 321 * messages that might be generated after the connection has closed. 322 */ 323 (void)ssh_remote_ipaddr(ssh); 324 return ssh; 325 } 326 327 void 328 ssh_packet_set_timeout(struct ssh *ssh, int timeout, int count) 329 { 330 struct session_state *state = ssh->state; 331 332 if (timeout <= 0 || count <= 0) { 333 state->packet_timeout_ms = -1; 334 return; 335 } 336 if ((INT_MAX / 1000) / count < timeout) 337 state->packet_timeout_ms = INT_MAX; 338 else 339 state->packet_timeout_ms = timeout * count * 1000; 340 } 341 342 void 343 ssh_packet_set_mux(struct ssh *ssh) 344 { 345 ssh->state->mux = 1; 346 ssh->state->rekeying = 0; 347 } 348 349 int 350 ssh_packet_get_mux(struct ssh *ssh) 351 { 352 return ssh->state->mux; 353 } 354 355 int 356 ssh_packet_stop_discard(struct ssh *ssh) 357 { 358 struct session_state *state = ssh->state; 359 int r; 360 361 if (state->packet_discard_mac) { 362 char buf[1024]; 363 size_t dlen = PACKET_MAX_SIZE; 364 365 if (dlen > state->packet_discard_mac_already) 366 dlen -= state->packet_discard_mac_already; 367 memset(buf, 'a', sizeof(buf)); 368 while (sshbuf_len(state->incoming_packet) < dlen) 369 if ((r = sshbuf_put(state->incoming_packet, buf, 370 sizeof(buf))) != 0) 371 return r; 372 (void) mac_compute(state->packet_discard_mac, 373 state->p_read.seqnr, 374 sshbuf_ptr(state->incoming_packet), dlen, 375 NULL, 0); 376 } 377 logit("Finished discarding for %.200s port %d", 378 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 379 return SSH_ERR_MAC_INVALID; 380 } 381 382 static int 383 ssh_packet_start_discard(struct ssh *ssh, struct sshenc *enc, 384 struct sshmac *mac, size_t mac_already, u_int discard) 385 { 386 struct session_state *state = ssh->state; 387 int r; 388 389 if (enc == NULL || !cipher_is_cbc(enc->cipher) || (mac && mac->etm)) { 390 if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0) 391 return r; 392 return SSH_ERR_MAC_INVALID; 393 } 394 /* 395 * Record number of bytes over which the mac has already 396 * been computed in order to minimize timing attacks. 397 */ 398 if (mac && mac->enabled) { 399 state->packet_discard_mac = mac; 400 state->packet_discard_mac_already = mac_already; 401 } 402 if (sshbuf_len(state->input) >= discard) 403 return ssh_packet_stop_discard(ssh); 404 state->packet_discard = discard - sshbuf_len(state->input); 405 return 0; 406 } 407 408 /* Returns 1 if remote host is connected via socket, 0 if not. */ 409 410 int 411 ssh_packet_connection_is_on_socket(struct ssh *ssh) 412 { 413 struct session_state *state = ssh->state; 414 struct sockaddr_storage from, to; 415 socklen_t fromlen, tolen; 416 417 if (state->connection_in == -1 || state->connection_out == -1) 418 return 0; 419 420 /* filedescriptors in and out are the same, so it's a socket */ 421 if (state->connection_in == state->connection_out) 422 return 1; 423 fromlen = sizeof(from); 424 memset(&from, 0, sizeof(from)); 425 if (getpeername(state->connection_in, (struct sockaddr *)&from, 426 &fromlen) < 0) 427 return 0; 428 tolen = sizeof(to); 429 memset(&to, 0, sizeof(to)); 430 if (getpeername(state->connection_out, (struct sockaddr *)&to, 431 &tolen) < 0) 432 return 0; 433 if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0) 434 return 0; 435 if (from.ss_family != AF_INET && from.ss_family != AF_INET6) 436 return 0; 437 return 1; 438 } 439 440 void 441 ssh_packet_get_bytes(struct ssh *ssh, u_int64_t *ibytes, u_int64_t *obytes) 442 { 443 if (ibytes) 444 *ibytes = ssh->state->p_read.bytes; 445 if (obytes) 446 *obytes = ssh->state->p_send.bytes; 447 } 448 449 int 450 ssh_packet_connection_af(struct ssh *ssh) 451 { 452 struct sockaddr_storage to; 453 socklen_t tolen = sizeof(to); 454 455 memset(&to, 0, sizeof(to)); 456 if (getsockname(ssh->state->connection_out, (struct sockaddr *)&to, 457 &tolen) < 0) 458 return 0; 459 return to.ss_family; 460 } 461 462 /* Sets the connection into non-blocking mode. */ 463 464 void 465 ssh_packet_set_nonblocking(struct ssh *ssh) 466 { 467 /* Set the socket into non-blocking mode. */ 468 set_nonblock(ssh->state->connection_in); 469 470 if (ssh->state->connection_out != ssh->state->connection_in) 471 set_nonblock(ssh->state->connection_out); 472 } 473 474 /* Returns the socket used for reading. */ 475 476 int 477 ssh_packet_get_connection_in(struct ssh *ssh) 478 { 479 return ssh->state->connection_in; 480 } 481 482 /* Returns the descriptor used for writing. */ 483 484 int 485 ssh_packet_get_connection_out(struct ssh *ssh) 486 { 487 return ssh->state->connection_out; 488 } 489 490 /* 491 * Returns the IP-address of the remote host as a string. The returned 492 * string must not be freed. 493 */ 494 495 const char * 496 ssh_remote_ipaddr(struct ssh *ssh) 497 { 498 const int sock = ssh->state->connection_in; 499 500 /* Check whether we have cached the ipaddr. */ 501 if (ssh->remote_ipaddr == NULL) { 502 if (ssh_packet_connection_is_on_socket(ssh)) { 503 ssh->remote_ipaddr = get_peer_ipaddr(sock); 504 ssh->remote_port = get_peer_port(sock); 505 ssh->local_ipaddr = get_local_ipaddr(sock); 506 ssh->local_port = get_local_port(sock); 507 } else { 508 ssh->remote_ipaddr = strdup("UNKNOWN"); 509 ssh->remote_port = 65535; 510 ssh->local_ipaddr = strdup("UNKNOWN"); 511 ssh->local_port = 65535; 512 } 513 } 514 return ssh->remote_ipaddr; 515 } 516 517 /* Returns the port number of the remote host. */ 518 519 int 520 ssh_remote_port(struct ssh *ssh) 521 { 522 (void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */ 523 return ssh->remote_port; 524 } 525 526 /* 527 * Returns the IP-address of the local host as a string. The returned 528 * string must not be freed. 529 */ 530 531 const char * 532 ssh_local_ipaddr(struct ssh *ssh) 533 { 534 (void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */ 535 return ssh->local_ipaddr; 536 } 537 538 /* Returns the port number of the local host. */ 539 540 int 541 ssh_local_port(struct ssh *ssh) 542 { 543 (void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */ 544 return ssh->local_port; 545 } 546 547 /* Closes the connection and clears and frees internal data structures. */ 548 549 void 550 ssh_packet_close(struct ssh *ssh) 551 { 552 struct session_state *state = ssh->state; 553 u_int mode; 554 555 if (!state->initialized) 556 return; 557 state->initialized = 0; 558 if (state->connection_in == state->connection_out) { 559 shutdown(state->connection_out, SHUT_RDWR); 560 close(state->connection_out); 561 } else { 562 close(state->connection_in); 563 close(state->connection_out); 564 } 565 sshbuf_free(state->input); 566 sshbuf_free(state->output); 567 sshbuf_free(state->outgoing_packet); 568 sshbuf_free(state->incoming_packet); 569 for (mode = 0; mode < MODE_MAX; mode++) 570 kex_free_newkeys(state->newkeys[mode]); 571 if (state->compression_buffer) { 572 sshbuf_free(state->compression_buffer); 573 if (state->compression_out_started) { 574 z_streamp stream = &state->compression_out_stream; 575 debug("compress outgoing: " 576 "raw data %llu, compressed %llu, factor %.2f", 577 (unsigned long long)stream->total_in, 578 (unsigned long long)stream->total_out, 579 stream->total_in == 0 ? 0.0 : 580 (double) stream->total_out / stream->total_in); 581 if (state->compression_out_failures == 0) 582 deflateEnd(stream); 583 } 584 if (state->compression_in_started) { 585 z_streamp stream = &state->compression_out_stream; 586 debug("compress incoming: " 587 "raw data %llu, compressed %llu, factor %.2f", 588 (unsigned long long)stream->total_out, 589 (unsigned long long)stream->total_in, 590 stream->total_out == 0 ? 0.0 : 591 (double) stream->total_in / stream->total_out); 592 if (state->compression_in_failures == 0) 593 inflateEnd(stream); 594 } 595 } 596 cipher_free(state->send_context); 597 cipher_free(state->receive_context); 598 state->send_context = state->receive_context = NULL; 599 free(ssh->remote_ipaddr); 600 ssh->remote_ipaddr = NULL; 601 free(ssh->state); 602 ssh->state = NULL; 603 } 604 605 /* Sets remote side protocol flags. */ 606 607 void 608 ssh_packet_set_protocol_flags(struct ssh *ssh, u_int protocol_flags) 609 { 610 ssh->state->remote_protocol_flags = protocol_flags; 611 } 612 613 /* Returns the remote protocol flags set earlier by the above function. */ 614 615 u_int 616 ssh_packet_get_protocol_flags(struct ssh *ssh) 617 { 618 return ssh->state->remote_protocol_flags; 619 } 620 621 /* 622 * Starts packet compression from the next packet on in both directions. 623 * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip. 624 */ 625 626 static int 627 ssh_packet_init_compression(struct ssh *ssh) 628 { 629 if (!ssh->state->compression_buffer && 630 ((ssh->state->compression_buffer = sshbuf_new()) == NULL)) 631 return SSH_ERR_ALLOC_FAIL; 632 return 0; 633 } 634 635 static int 636 start_compression_out(struct ssh *ssh, int level) 637 { 638 if (level < 1 || level > 9) 639 return SSH_ERR_INVALID_ARGUMENT; 640 debug("Enabling compression at level %d.", level); 641 if (ssh->state->compression_out_started == 1) 642 deflateEnd(&ssh->state->compression_out_stream); 643 switch (deflateInit(&ssh->state->compression_out_stream, level)) { 644 case Z_OK: 645 ssh->state->compression_out_started = 1; 646 break; 647 case Z_MEM_ERROR: 648 return SSH_ERR_ALLOC_FAIL; 649 default: 650 return SSH_ERR_INTERNAL_ERROR; 651 } 652 return 0; 653 } 654 655 static int 656 start_compression_in(struct ssh *ssh) 657 { 658 if (ssh->state->compression_in_started == 1) 659 inflateEnd(&ssh->state->compression_in_stream); 660 switch (inflateInit(&ssh->state->compression_in_stream)) { 661 case Z_OK: 662 ssh->state->compression_in_started = 1; 663 break; 664 case Z_MEM_ERROR: 665 return SSH_ERR_ALLOC_FAIL; 666 default: 667 return SSH_ERR_INTERNAL_ERROR; 668 } 669 return 0; 670 } 671 672 int 673 ssh_packet_start_compression(struct ssh *ssh, int level) 674 { 675 int r; 676 677 if (ssh->state->packet_compression && !compat20) 678 return SSH_ERR_INTERNAL_ERROR; 679 ssh->state->packet_compression = 1; 680 if ((r = ssh_packet_init_compression(ssh)) != 0 || 681 (r = start_compression_in(ssh)) != 0 || 682 (r = start_compression_out(ssh, level)) != 0) 683 return r; 684 return 0; 685 } 686 687 /* XXX remove need for separate compression buffer */ 688 static int 689 compress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out) 690 { 691 u_char buf[4096]; 692 int r, status; 693 694 if (ssh->state->compression_out_started != 1) 695 return SSH_ERR_INTERNAL_ERROR; 696 697 /* This case is not handled below. */ 698 if (sshbuf_len(in) == 0) 699 return 0; 700 701 /* Input is the contents of the input buffer. */ 702 if ((ssh->state->compression_out_stream.next_in = 703 sshbuf_mutable_ptr(in)) == NULL) 704 return SSH_ERR_INTERNAL_ERROR; 705 ssh->state->compression_out_stream.avail_in = sshbuf_len(in); 706 707 /* Loop compressing until deflate() returns with avail_out != 0. */ 708 do { 709 /* Set up fixed-size output buffer. */ 710 ssh->state->compression_out_stream.next_out = buf; 711 ssh->state->compression_out_stream.avail_out = sizeof(buf); 712 713 /* Compress as much data into the buffer as possible. */ 714 status = deflate(&ssh->state->compression_out_stream, 715 Z_PARTIAL_FLUSH); 716 switch (status) { 717 case Z_MEM_ERROR: 718 return SSH_ERR_ALLOC_FAIL; 719 case Z_OK: 720 /* Append compressed data to output_buffer. */ 721 if ((r = sshbuf_put(out, buf, sizeof(buf) - 722 ssh->state->compression_out_stream.avail_out)) != 0) 723 return r; 724 break; 725 case Z_STREAM_ERROR: 726 default: 727 ssh->state->compression_out_failures++; 728 return SSH_ERR_INVALID_FORMAT; 729 } 730 } while (ssh->state->compression_out_stream.avail_out == 0); 731 return 0; 732 } 733 734 static int 735 uncompress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out) 736 { 737 u_char buf[4096]; 738 int r, status; 739 740 if (ssh->state->compression_in_started != 1) 741 return SSH_ERR_INTERNAL_ERROR; 742 743 if ((ssh->state->compression_in_stream.next_in = 744 sshbuf_mutable_ptr(in)) == NULL) 745 return SSH_ERR_INTERNAL_ERROR; 746 ssh->state->compression_in_stream.avail_in = sshbuf_len(in); 747 748 for (;;) { 749 /* Set up fixed-size output buffer. */ 750 ssh->state->compression_in_stream.next_out = buf; 751 ssh->state->compression_in_stream.avail_out = sizeof(buf); 752 753 status = inflate(&ssh->state->compression_in_stream, 754 Z_PARTIAL_FLUSH); 755 switch (status) { 756 case Z_OK: 757 if ((r = sshbuf_put(out, buf, sizeof(buf) - 758 ssh->state->compression_in_stream.avail_out)) != 0) 759 return r; 760 break; 761 case Z_BUF_ERROR: 762 /* 763 * Comments in zlib.h say that we should keep calling 764 * inflate() until we get an error. This appears to 765 * be the error that we get. 766 */ 767 return 0; 768 case Z_DATA_ERROR: 769 return SSH_ERR_INVALID_FORMAT; 770 case Z_MEM_ERROR: 771 return SSH_ERR_ALLOC_FAIL; 772 case Z_STREAM_ERROR: 773 default: 774 ssh->state->compression_in_failures++; 775 return SSH_ERR_INTERNAL_ERROR; 776 } 777 } 778 /* NOTREACHED */ 779 } 780 781 /* 782 * Causes any further packets to be encrypted using the given key. The same 783 * key is used for both sending and reception. However, both directions are 784 * encrypted independently of each other. 785 */ 786 787 void 788 ssh_packet_set_encryption_key(struct ssh *ssh, const u_char *key, u_int keylen, int number) 789 { 790 #ifndef WITH_SSH1 791 fatal("no SSH protocol 1 support"); 792 #else /* WITH_SSH1 */ 793 struct session_state *state = ssh->state; 794 const struct sshcipher *cipher = cipher_by_number(number); 795 int r; 796 const char *wmsg; 797 798 if (cipher == NULL) 799 fatal("%s: unknown cipher number %d", __func__, number); 800 if (keylen < 20) 801 fatal("%s: keylen too small: %d", __func__, keylen); 802 if (keylen > SSH_SESSION_KEY_LENGTH) 803 fatal("%s: keylen too big: %d", __func__, keylen); 804 memcpy(state->ssh1_key, key, keylen); 805 state->ssh1_keylen = keylen; 806 if ((r = cipher_init(&state->send_context, cipher, key, keylen, 807 NULL, 0, CIPHER_ENCRYPT)) != 0 || 808 (r = cipher_init(&state->receive_context, cipher, key, keylen, 809 NULL, 0, CIPHER_DECRYPT) != 0)) 810 fatal("%s: cipher_init failed: %s", __func__, ssh_err(r)); 811 if (!state->cipher_warning_done && 812 ((wmsg = cipher_warning_message(state->send_context)) != NULL || 813 (wmsg = cipher_warning_message(state->send_context)) != NULL)) { 814 error("Warning: %s", wmsg); 815 state->cipher_warning_done = 1; 816 } 817 #endif /* WITH_SSH1 */ 818 } 819 820 /* 821 * Finalizes and sends the packet. If the encryption key has been set, 822 * encrypts the packet before sending. 823 */ 824 825 int 826 ssh_packet_send1(struct ssh *ssh) 827 { 828 struct session_state *state = ssh->state; 829 u_char buf[8], *cp; 830 int r, padding, len; 831 u_int checksum; 832 833 /* 834 * If using packet compression, compress the payload of the outgoing 835 * packet. 836 */ 837 if (state->packet_compression) { 838 sshbuf_reset(state->compression_buffer); 839 /* Skip padding. */ 840 if ((r = sshbuf_consume(state->outgoing_packet, 8)) != 0) 841 goto out; 842 /* padding */ 843 if ((r = sshbuf_put(state->compression_buffer, 844 "\0\0\0\0\0\0\0\0", 8)) != 0) 845 goto out; 846 if ((r = compress_buffer(ssh, state->outgoing_packet, 847 state->compression_buffer)) != 0) 848 goto out; 849 sshbuf_reset(state->outgoing_packet); 850 if ((r = sshbuf_putb(state->outgoing_packet, 851 state->compression_buffer)) != 0) 852 goto out; 853 } 854 /* Compute packet length without padding (add checksum, remove padding). */ 855 len = sshbuf_len(state->outgoing_packet) + 4 - 8; 856 857 /* Insert padding. Initialized to zero in packet_start1() */ 858 padding = 8 - len % 8; 859 if (!cipher_ctx_is_plaintext(state->send_context)) { 860 cp = sshbuf_mutable_ptr(state->outgoing_packet); 861 if (cp == NULL) { 862 r = SSH_ERR_INTERNAL_ERROR; 863 goto out; 864 } 865 arc4random_buf(cp + 8 - padding, padding); 866 } 867 if ((r = sshbuf_consume(state->outgoing_packet, 8 - padding)) != 0) 868 goto out; 869 870 /* Add check bytes. */ 871 checksum = ssh_crc32(sshbuf_ptr(state->outgoing_packet), 872 sshbuf_len(state->outgoing_packet)); 873 POKE_U32(buf, checksum); 874 if ((r = sshbuf_put(state->outgoing_packet, buf, 4)) != 0) 875 goto out; 876 877 #ifdef PACKET_DEBUG 878 fprintf(stderr, "packet_send plain: "); 879 sshbuf_dump(state->outgoing_packet, stderr); 880 #endif 881 882 /* Append to output. */ 883 POKE_U32(buf, len); 884 if ((r = sshbuf_put(state->output, buf, 4)) != 0) 885 goto out; 886 if ((r = sshbuf_reserve(state->output, 887 sshbuf_len(state->outgoing_packet), &cp)) != 0) 888 goto out; 889 if ((r = cipher_crypt(state->send_context, 0, cp, 890 sshbuf_ptr(state->outgoing_packet), 891 sshbuf_len(state->outgoing_packet), 0, 0)) != 0) 892 goto out; 893 894 #ifdef PACKET_DEBUG 895 fprintf(stderr, "encrypted: "); 896 sshbuf_dump(state->output, stderr); 897 #endif 898 state->p_send.packets++; 899 state->p_send.bytes += len + 900 sshbuf_len(state->outgoing_packet); 901 sshbuf_reset(state->outgoing_packet); 902 903 /* 904 * Note that the packet is now only buffered in output. It won't be 905 * actually sent until ssh_packet_write_wait or ssh_packet_write_poll 906 * is called. 907 */ 908 r = 0; 909 out: 910 return r; 911 } 912 913 int 914 ssh_set_newkeys(struct ssh *ssh, int mode) 915 { 916 struct session_state *state = ssh->state; 917 struct sshenc *enc; 918 struct sshmac *mac; 919 struct sshcomp *comp; 920 struct sshcipher_ctx **ccp; 921 struct packet_state *ps; 922 u_int64_t *max_blocks; 923 const char *wmsg, *dir; 924 int r, crypt_type; 925 926 debug2("set_newkeys: mode %d", mode); 927 928 if (mode == MODE_OUT) { 929 dir = "output"; 930 ccp = &state->send_context; 931 crypt_type = CIPHER_ENCRYPT; 932 ps = &state->p_send; 933 max_blocks = &state->max_blocks_out; 934 } else { 935 dir = "input"; 936 ccp = &state->receive_context; 937 crypt_type = CIPHER_DECRYPT; 938 ps = &state->p_read; 939 max_blocks = &state->max_blocks_in; 940 } 941 if (state->newkeys[mode] != NULL) { 942 debug("%s: rekeying after %llu %s blocks" 943 " (%llu bytes total)", __func__, 944 (unsigned long long)ps->blocks, dir, 945 (unsigned long long)ps->bytes); 946 cipher_free(*ccp); 947 *ccp = NULL; 948 enc = &state->newkeys[mode]->enc; 949 mac = &state->newkeys[mode]->mac; 950 comp = &state->newkeys[mode]->comp; 951 mac_clear(mac); 952 explicit_bzero(enc->iv, enc->iv_len); 953 explicit_bzero(enc->key, enc->key_len); 954 explicit_bzero(mac->key, mac->key_len); 955 free(enc->name); 956 free(enc->iv); 957 free(enc->key); 958 free(mac->name); 959 free(mac->key); 960 free(comp->name); 961 free(state->newkeys[mode]); 962 } 963 /* note that both bytes and the seqnr are not reset */ 964 ps->packets = ps->blocks = 0; 965 /* move newkeys from kex to state */ 966 if ((state->newkeys[mode] = ssh->kex->newkeys[mode]) == NULL) 967 return SSH_ERR_INTERNAL_ERROR; 968 ssh->kex->newkeys[mode] = NULL; 969 enc = &state->newkeys[mode]->enc; 970 mac = &state->newkeys[mode]->mac; 971 comp = &state->newkeys[mode]->comp; 972 if (cipher_authlen(enc->cipher) == 0) { 973 if ((r = mac_init(mac)) != 0) 974 return r; 975 } 976 mac->enabled = 1; 977 DBG(debug("cipher_init_context: %d", mode)); 978 if ((r = cipher_init(ccp, enc->cipher, enc->key, enc->key_len, 979 enc->iv, enc->iv_len, crypt_type)) != 0) 980 return r; 981 if (!state->cipher_warning_done && 982 (wmsg = cipher_warning_message(*ccp)) != NULL) { 983 error("Warning: %s", wmsg); 984 state->cipher_warning_done = 1; 985 } 986 /* Deleting the keys does not gain extra security */ 987 /* explicit_bzero(enc->iv, enc->block_size); 988 explicit_bzero(enc->key, enc->key_len); 989 explicit_bzero(mac->key, mac->key_len); */ 990 if ((comp->type == COMP_ZLIB || 991 (comp->type == COMP_DELAYED && 992 state->after_authentication)) && comp->enabled == 0) { 993 if ((r = ssh_packet_init_compression(ssh)) < 0) 994 return r; 995 if (mode == MODE_OUT) { 996 if ((r = start_compression_out(ssh, 6)) != 0) 997 return r; 998 } else { 999 if ((r = start_compression_in(ssh)) != 0) 1000 return r; 1001 } 1002 comp->enabled = 1; 1003 } 1004 /* 1005 * The 2^(blocksize*2) limit is too expensive for 3DES, 1006 * blowfish, etc, so enforce a 1GB limit for small blocksizes. 1007 */ 1008 if (enc->block_size >= 16) 1009 *max_blocks = (u_int64_t)1 << (enc->block_size*2); 1010 else 1011 *max_blocks = ((u_int64_t)1 << 30) / enc->block_size; 1012 if (state->rekey_limit) 1013 *max_blocks = MINIMUM(*max_blocks, 1014 state->rekey_limit / enc->block_size); 1015 debug("rekey after %llu blocks", (unsigned long long)*max_blocks); 1016 return 0; 1017 } 1018 1019 #define MAX_PACKETS (1U<<31) 1020 static int 1021 ssh_packet_need_rekeying(struct ssh *ssh, u_int outbound_packet_len) 1022 { 1023 struct session_state *state = ssh->state; 1024 u_int32_t out_blocks; 1025 1026 /* XXX client can't cope with rekeying pre-auth */ 1027 if (!state->after_authentication) 1028 return 0; 1029 1030 /* Haven't keyed yet or KEX in progress. */ 1031 if (ssh->kex == NULL || ssh_packet_is_rekeying(ssh)) 1032 return 0; 1033 1034 /* Peer can't rekey */ 1035 if (ssh->compat & SSH_BUG_NOREKEY) 1036 return 0; 1037 1038 /* 1039 * Permit one packet in or out per rekey - this allows us to 1040 * make progress when rekey limits are very small. 1041 */ 1042 if (state->p_send.packets == 0 && state->p_read.packets == 0) 1043 return 0; 1044 1045 /* Time-based rekeying */ 1046 if (state->rekey_interval != 0 && 1047 state->rekey_time + state->rekey_interval <= monotime()) 1048 return 1; 1049 1050 /* Always rekey when MAX_PACKETS sent in either direction */ 1051 if (state->p_send.packets > MAX_PACKETS || 1052 state->p_read.packets > MAX_PACKETS) 1053 return 1; 1054 1055 /* Rekey after (cipher-specific) maxiumum blocks */ 1056 out_blocks = ROUNDUP(outbound_packet_len, 1057 state->newkeys[MODE_OUT]->enc.block_size); 1058 return (state->max_blocks_out && 1059 (state->p_send.blocks + out_blocks > state->max_blocks_out)) || 1060 (state->max_blocks_in && 1061 (state->p_read.blocks > state->max_blocks_in)); 1062 } 1063 1064 /* 1065 * Delayed compression for SSH2 is enabled after authentication: 1066 * This happens on the server side after a SSH2_MSG_USERAUTH_SUCCESS is sent, 1067 * and on the client side after a SSH2_MSG_USERAUTH_SUCCESS is received. 1068 */ 1069 static int 1070 ssh_packet_enable_delayed_compress(struct ssh *ssh) 1071 { 1072 struct session_state *state = ssh->state; 1073 struct sshcomp *comp = NULL; 1074 int r, mode; 1075 1076 /* 1077 * Remember that we are past the authentication step, so rekeying 1078 * with COMP_DELAYED will turn on compression immediately. 1079 */ 1080 state->after_authentication = 1; 1081 for (mode = 0; mode < MODE_MAX; mode++) { 1082 /* protocol error: USERAUTH_SUCCESS received before NEWKEYS */ 1083 if (state->newkeys[mode] == NULL) 1084 continue; 1085 comp = &state->newkeys[mode]->comp; 1086 if (comp && !comp->enabled && comp->type == COMP_DELAYED) { 1087 if ((r = ssh_packet_init_compression(ssh)) != 0) 1088 return r; 1089 if (mode == MODE_OUT) { 1090 if ((r = start_compression_out(ssh, 6)) != 0) 1091 return r; 1092 } else { 1093 if ((r = start_compression_in(ssh)) != 0) 1094 return r; 1095 } 1096 comp->enabled = 1; 1097 } 1098 } 1099 return 0; 1100 } 1101 1102 /* Used to mute debug logging for noisy packet types */ 1103 int 1104 ssh_packet_log_type(u_char type) 1105 { 1106 switch (type) { 1107 case SSH2_MSG_CHANNEL_DATA: 1108 case SSH2_MSG_CHANNEL_EXTENDED_DATA: 1109 case SSH2_MSG_CHANNEL_WINDOW_ADJUST: 1110 return 0; 1111 default: 1112 return 1; 1113 } 1114 } 1115 1116 /* 1117 * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue) 1118 */ 1119 int 1120 ssh_packet_send2_wrapped(struct ssh *ssh) 1121 { 1122 struct session_state *state = ssh->state; 1123 u_char type, *cp, macbuf[SSH_DIGEST_MAX_LENGTH]; 1124 u_char tmp, padlen, pad = 0; 1125 u_int authlen = 0, aadlen = 0; 1126 u_int len; 1127 struct sshenc *enc = NULL; 1128 struct sshmac *mac = NULL; 1129 struct sshcomp *comp = NULL; 1130 int r, block_size; 1131 1132 if (state->newkeys[MODE_OUT] != NULL) { 1133 enc = &state->newkeys[MODE_OUT]->enc; 1134 mac = &state->newkeys[MODE_OUT]->mac; 1135 comp = &state->newkeys[MODE_OUT]->comp; 1136 /* disable mac for authenticated encryption */ 1137 if ((authlen = cipher_authlen(enc->cipher)) != 0) 1138 mac = NULL; 1139 } 1140 block_size = enc ? enc->block_size : 8; 1141 aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0; 1142 1143 type = (sshbuf_ptr(state->outgoing_packet))[5]; 1144 if (ssh_packet_log_type(type)) 1145 debug3("send packet: type %u", type); 1146 #ifdef PACKET_DEBUG 1147 fprintf(stderr, "plain: "); 1148 sshbuf_dump(state->outgoing_packet, stderr); 1149 #endif 1150 1151 if (comp && comp->enabled) { 1152 len = sshbuf_len(state->outgoing_packet); 1153 /* skip header, compress only payload */ 1154 if ((r = sshbuf_consume(state->outgoing_packet, 5)) != 0) 1155 goto out; 1156 sshbuf_reset(state->compression_buffer); 1157 if ((r = compress_buffer(ssh, state->outgoing_packet, 1158 state->compression_buffer)) != 0) 1159 goto out; 1160 sshbuf_reset(state->outgoing_packet); 1161 if ((r = sshbuf_put(state->outgoing_packet, 1162 "\0\0\0\0\0", 5)) != 0 || 1163 (r = sshbuf_putb(state->outgoing_packet, 1164 state->compression_buffer)) != 0) 1165 goto out; 1166 DBG(debug("compression: raw %d compressed %zd", len, 1167 sshbuf_len(state->outgoing_packet))); 1168 } 1169 1170 /* sizeof (packet_len + pad_len + payload) */ 1171 len = sshbuf_len(state->outgoing_packet); 1172 1173 /* 1174 * calc size of padding, alloc space, get random data, 1175 * minimum padding is 4 bytes 1176 */ 1177 len -= aadlen; /* packet length is not encrypted for EtM modes */ 1178 padlen = block_size - (len % block_size); 1179 if (padlen < 4) 1180 padlen += block_size; 1181 if (state->extra_pad) { 1182 tmp = state->extra_pad; 1183 state->extra_pad = 1184 ROUNDUP(state->extra_pad, block_size); 1185 /* check if roundup overflowed */ 1186 if (state->extra_pad < tmp) 1187 return SSH_ERR_INVALID_ARGUMENT; 1188 tmp = (len + padlen) % state->extra_pad; 1189 /* Check whether pad calculation below will underflow */ 1190 if (tmp > state->extra_pad) 1191 return SSH_ERR_INVALID_ARGUMENT; 1192 pad = state->extra_pad - tmp; 1193 DBG(debug3("%s: adding %d (len %d padlen %d extra_pad %d)", 1194 __func__, pad, len, padlen, state->extra_pad)); 1195 tmp = padlen; 1196 padlen += pad; 1197 /* Check whether padlen calculation overflowed */ 1198 if (padlen < tmp) 1199 return SSH_ERR_INVALID_ARGUMENT; /* overflow */ 1200 state->extra_pad = 0; 1201 } 1202 if ((r = sshbuf_reserve(state->outgoing_packet, padlen, &cp)) != 0) 1203 goto out; 1204 if (enc && !cipher_ctx_is_plaintext(state->send_context)) { 1205 /* random padding */ 1206 arc4random_buf(cp, padlen); 1207 } else { 1208 /* clear padding */ 1209 explicit_bzero(cp, padlen); 1210 } 1211 /* sizeof (packet_len + pad_len + payload + padding) */ 1212 len = sshbuf_len(state->outgoing_packet); 1213 cp = sshbuf_mutable_ptr(state->outgoing_packet); 1214 if (cp == NULL) { 1215 r = SSH_ERR_INTERNAL_ERROR; 1216 goto out; 1217 } 1218 /* packet_length includes payload, padding and padding length field */ 1219 POKE_U32(cp, len - 4); 1220 cp[4] = padlen; 1221 DBG(debug("send: len %d (includes padlen %d, aadlen %d)", 1222 len, padlen, aadlen)); 1223 1224 /* compute MAC over seqnr and packet(length fields, payload, padding) */ 1225 debug("mac %p, %d %d", mac, mac? mac->enabled : -1, mac ? mac->etm : -1); 1226 if (mac && mac->enabled && !mac->etm) { 1227 if ((r = mac_compute(mac, state->p_send.seqnr, 1228 sshbuf_ptr(state->outgoing_packet), len, 1229 macbuf, sizeof(macbuf))) != 0) 1230 goto out; 1231 DBG(debug("done calc MAC out #%d", state->p_send.seqnr)); 1232 } 1233 /* encrypt packet and append to output buffer. */ 1234 if ((r = sshbuf_reserve(state->output, 1235 sshbuf_len(state->outgoing_packet) + authlen, &cp)) != 0) 1236 goto out; 1237 if ((r = cipher_crypt(state->send_context, state->p_send.seqnr, cp, 1238 sshbuf_ptr(state->outgoing_packet), 1239 len - aadlen, aadlen, authlen)) != 0) 1240 goto out; 1241 /* append unencrypted MAC */ 1242 if (mac && mac->enabled) { 1243 if (mac->etm) { 1244 /* EtM: compute mac over aadlen + cipher text */ 1245 if ((r = mac_compute(mac, state->p_send.seqnr, 1246 cp, len, macbuf, sizeof(macbuf))) != 0) 1247 goto out; 1248 DBG(debug("done calc MAC(EtM) out #%d", 1249 state->p_send.seqnr)); 1250 } 1251 if ((r = sshbuf_put(state->output, macbuf, mac->mac_len)) != 0) 1252 goto out; 1253 } 1254 #ifdef PACKET_DEBUG 1255 fprintf(stderr, "encrypted: "); 1256 sshbuf_dump(state->output, stderr); 1257 #endif 1258 /* increment sequence number for outgoing packets */ 1259 if (++state->p_send.seqnr == 0) 1260 logit("outgoing seqnr wraps around"); 1261 if (++state->p_send.packets == 0) 1262 if (!(ssh->compat & SSH_BUG_NOREKEY)) 1263 return SSH_ERR_NEED_REKEY; 1264 state->p_send.blocks += len / block_size; 1265 state->p_send.bytes += len; 1266 sshbuf_reset(state->outgoing_packet); 1267 1268 if (type == SSH2_MSG_NEWKEYS) 1269 r = ssh_set_newkeys(ssh, MODE_OUT); 1270 else if (type == SSH2_MSG_USERAUTH_SUCCESS && state->server_side) 1271 r = ssh_packet_enable_delayed_compress(ssh); 1272 else 1273 r = 0; 1274 out: 1275 if (r < 0) 1276 return r; 1277 else 1278 return len - 4; 1279 } 1280 1281 /* returns non-zero if the specified packet type is usec by KEX */ 1282 static int 1283 ssh_packet_type_is_kex(u_char type) 1284 { 1285 return 1286 type >= SSH2_MSG_TRANSPORT_MIN && 1287 type <= SSH2_MSG_TRANSPORT_MAX && 1288 type != SSH2_MSG_SERVICE_REQUEST && 1289 type != SSH2_MSG_SERVICE_ACCEPT && 1290 type != SSH2_MSG_EXT_INFO; 1291 } 1292 1293 int 1294 ssh_packet_send2(struct ssh *ssh) 1295 { 1296 struct session_state *state = ssh->state; 1297 struct packet *p; 1298 u_char type; 1299 int r, need_rekey; 1300 int packet_length; 1301 1302 if (sshbuf_len(state->outgoing_packet) < 6) 1303 return SSH_ERR_INTERNAL_ERROR; 1304 type = sshbuf_ptr(state->outgoing_packet)[5]; 1305 need_rekey = !ssh_packet_type_is_kex(type) && 1306 ssh_packet_need_rekeying(ssh, sshbuf_len(state->outgoing_packet)); 1307 1308 /* 1309 * During rekeying we can only send key exchange messages. 1310 * Queue everything else. 1311 */ 1312 if ((need_rekey || state->rekeying) && !ssh_packet_type_is_kex(type)) { 1313 if (need_rekey) 1314 debug3("%s: rekex triggered", __func__); 1315 debug("enqueue packet: %u", type); 1316 p = calloc(1, sizeof(*p)); 1317 if (p == NULL) 1318 return SSH_ERR_ALLOC_FAIL; 1319 p->type = type; 1320 p->payload = state->outgoing_packet; 1321 TAILQ_INSERT_TAIL(&state->outgoing, p, next); 1322 state->outgoing_packet = sshbuf_new(); 1323 if (state->outgoing_packet == NULL) 1324 return SSH_ERR_ALLOC_FAIL; 1325 if (need_rekey) { 1326 /* 1327 * This packet triggered a rekey, so send the 1328 * KEXINIT now. 1329 * NB. reenters this function via kex_start_rekex(). 1330 */ 1331 return kex_start_rekex(ssh); 1332 } 1333 return 0; 1334 } 1335 1336 /* rekeying starts with sending KEXINIT */ 1337 if (type == SSH2_MSG_KEXINIT) 1338 state->rekeying = 1; 1339 1340 if ((r = ssh_packet_send2_wrapped(ssh)) < 0) 1341 return r; 1342 1343 packet_length = r; 1344 1345 /* after a NEWKEYS message we can send the complete queue */ 1346 if (type == SSH2_MSG_NEWKEYS) { 1347 state->rekeying = 0; 1348 state->rekey_time = monotime(); 1349 while ((p = TAILQ_FIRST(&state->outgoing))) { 1350 type = p->type; 1351 /* 1352 * If this packet triggers a rekex, then skip the 1353 * remaining packets in the queue for now. 1354 * NB. re-enters this function via kex_start_rekex. 1355 */ 1356 if (ssh_packet_need_rekeying(ssh, 1357 sshbuf_len(p->payload))) { 1358 debug3("%s: queued packet triggered rekex", 1359 __func__); 1360 return kex_start_rekex(ssh); 1361 } 1362 debug("dequeue packet: %u", type); 1363 sshbuf_free(state->outgoing_packet); 1364 state->outgoing_packet = p->payload; 1365 TAILQ_REMOVE(&state->outgoing, p, next); 1366 memset(p, 0, sizeof(*p)); 1367 free(p); 1368 if ((r = ssh_packet_send2_wrapped(ssh)) < 0) 1369 return r; 1370 packet_length += r; 1371 } 1372 } 1373 return packet_length; 1374 } 1375 1376 /* 1377 * Waits until a packet has been received, and returns its type. Note that 1378 * no other data is processed until this returns, so this function should not 1379 * be used during the interactive session. 1380 */ 1381 1382 int 1383 ssh_packet_read_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1384 { 1385 struct session_state *state = ssh->state; 1386 int len, r, ms_remain = 0; 1387 fd_set *setp; 1388 char buf[8192]; 1389 struct timeval timeout, start, *timeoutp = NULL; 1390 1391 DBG(debug("packet_read()")); 1392 1393 setp = calloc(howmany(state->connection_in + 1, 1394 NFDBITS), sizeof(fd_mask)); 1395 if (setp == NULL) 1396 return SSH_ERR_ALLOC_FAIL; 1397 1398 /* 1399 * Since we are blocking, ensure that all written packets have 1400 * been sent. 1401 */ 1402 if ((r = ssh_packet_write_wait(ssh)) < 0) 1403 goto out; 1404 1405 /* Stay in the loop until we have received a complete packet. */ 1406 for (;;) { 1407 /* Try to read a packet from the buffer. */ 1408 r = ssh_packet_read_poll_seqnr(ssh, typep, seqnr_p); 1409 if (r != 0) 1410 break; 1411 if (!compat20 && ( 1412 *typep == SSH_SMSG_SUCCESS 1413 || *typep == SSH_SMSG_FAILURE 1414 || *typep == SSH_CMSG_EOF 1415 || *typep == SSH_CMSG_EXIT_CONFIRMATION)) 1416 if ((r = sshpkt_get_end(ssh)) != 0) 1417 break; 1418 /* If we got a packet, return it. */ 1419 if (*typep != SSH_MSG_NONE) 1420 break; 1421 /* 1422 * Otherwise, wait for some data to arrive, add it to the 1423 * buffer, and try again. 1424 */ 1425 memset(setp, 0, howmany(state->connection_in + 1, 1426 NFDBITS) * sizeof(fd_mask)); 1427 FD_SET(state->connection_in, setp); 1428 1429 if (state->packet_timeout_ms > 0) { 1430 ms_remain = state->packet_timeout_ms; 1431 timeoutp = &timeout; 1432 } 1433 /* Wait for some data to arrive. */ 1434 for (;;) { 1435 if (state->packet_timeout_ms != -1) { 1436 ms_to_timeval(&timeout, ms_remain); 1437 gettimeofday(&start, NULL); 1438 } 1439 if ((r = select(state->connection_in + 1, setp, 1440 NULL, NULL, timeoutp)) >= 0) 1441 break; 1442 if (errno != EAGAIN && errno != EINTR) 1443 break; 1444 if (state->packet_timeout_ms == -1) 1445 continue; 1446 ms_subtract_diff(&start, &ms_remain); 1447 if (ms_remain <= 0) { 1448 r = 0; 1449 break; 1450 } 1451 } 1452 if (r == 0) 1453 return SSH_ERR_CONN_TIMEOUT; 1454 /* Read data from the socket. */ 1455 len = read(state->connection_in, buf, sizeof(buf)); 1456 if (len == 0) { 1457 r = SSH_ERR_CONN_CLOSED; 1458 goto out; 1459 } 1460 if (len < 0) { 1461 r = SSH_ERR_SYSTEM_ERROR; 1462 goto out; 1463 } 1464 1465 /* Append it to the buffer. */ 1466 if ((r = ssh_packet_process_incoming(ssh, buf, len)) != 0) 1467 goto out; 1468 } 1469 out: 1470 free(setp); 1471 return r; 1472 } 1473 1474 int 1475 ssh_packet_read(struct ssh *ssh) 1476 { 1477 u_char type; 1478 int r; 1479 1480 if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0) 1481 fatal("%s: %s", __func__, ssh_err(r)); 1482 return type; 1483 } 1484 1485 /* 1486 * Waits until a packet has been received, verifies that its type matches 1487 * that given, and gives a fatal error and exits if there is a mismatch. 1488 */ 1489 1490 int 1491 ssh_packet_read_expect(struct ssh *ssh, u_int expected_type) 1492 { 1493 int r; 1494 u_char type; 1495 1496 if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0) 1497 return r; 1498 if (type != expected_type) { 1499 if ((r = sshpkt_disconnect(ssh, 1500 "Protocol error: expected packet type %d, got %d", 1501 expected_type, type)) != 0) 1502 return r; 1503 return SSH_ERR_PROTOCOL_ERROR; 1504 } 1505 return 0; 1506 } 1507 1508 /* Checks if a full packet is available in the data received so far via 1509 * packet_process_incoming. If so, reads the packet; otherwise returns 1510 * SSH_MSG_NONE. This does not wait for data from the connection. 1511 * 1512 * SSH_MSG_DISCONNECT is handled specially here. Also, 1513 * SSH_MSG_IGNORE messages are skipped by this function and are never returned 1514 * to higher levels. 1515 */ 1516 1517 int 1518 ssh_packet_read_poll1(struct ssh *ssh, u_char *typep) 1519 { 1520 struct session_state *state = ssh->state; 1521 u_int len, padded_len; 1522 const char *emsg; 1523 const u_char *cp; 1524 u_char *p; 1525 u_int checksum, stored_checksum; 1526 int r; 1527 1528 *typep = SSH_MSG_NONE; 1529 1530 /* Check if input size is less than minimum packet size. */ 1531 if (sshbuf_len(state->input) < 4 + 8) 1532 return 0; 1533 /* Get length of incoming packet. */ 1534 len = PEEK_U32(sshbuf_ptr(state->input)); 1535 if (len < 1 + 2 + 2 || len > 256 * 1024) { 1536 if ((r = sshpkt_disconnect(ssh, "Bad packet length %u", 1537 len)) != 0) 1538 return r; 1539 return SSH_ERR_CONN_CORRUPT; 1540 } 1541 padded_len = (len + 8) & ~7; 1542 1543 /* Check if the packet has been entirely received. */ 1544 if (sshbuf_len(state->input) < 4 + padded_len) 1545 return 0; 1546 1547 /* The entire packet is in buffer. */ 1548 1549 /* Consume packet length. */ 1550 if ((r = sshbuf_consume(state->input, 4)) != 0) 1551 goto out; 1552 1553 /* 1554 * Cryptographic attack detector for ssh 1555 * (C)1998 CORE-SDI, Buenos Aires Argentina 1556 * Ariel Futoransky(futo@core-sdi.com) 1557 */ 1558 if (!cipher_ctx_is_plaintext(state->receive_context)) { 1559 emsg = NULL; 1560 switch (detect_attack(&state->deattack, 1561 sshbuf_ptr(state->input), padded_len)) { 1562 case DEATTACK_OK: 1563 break; 1564 case DEATTACK_DETECTED: 1565 emsg = "crc32 compensation attack detected"; 1566 break; 1567 case DEATTACK_DOS_DETECTED: 1568 emsg = "deattack denial of service detected"; 1569 break; 1570 default: 1571 emsg = "deattack error"; 1572 break; 1573 } 1574 if (emsg != NULL) { 1575 error("%s", emsg); 1576 if ((r = sshpkt_disconnect(ssh, "%s", emsg)) != 0 || 1577 (r = ssh_packet_write_wait(ssh)) < 0) 1578 return r; 1579 return SSH_ERR_CONN_CORRUPT; 1580 } 1581 } 1582 1583 /* Decrypt data to incoming_packet. */ 1584 sshbuf_reset(state->incoming_packet); 1585 if ((r = sshbuf_reserve(state->incoming_packet, padded_len, &p)) != 0) 1586 goto out; 1587 if ((r = cipher_crypt(state->receive_context, 0, p, 1588 sshbuf_ptr(state->input), padded_len, 0, 0)) != 0) 1589 goto out; 1590 1591 if ((r = sshbuf_consume(state->input, padded_len)) != 0) 1592 goto out; 1593 1594 #ifdef PACKET_DEBUG 1595 fprintf(stderr, "read_poll plain: "); 1596 sshbuf_dump(state->incoming_packet, stderr); 1597 #endif 1598 1599 /* Compute packet checksum. */ 1600 checksum = ssh_crc32(sshbuf_ptr(state->incoming_packet), 1601 sshbuf_len(state->incoming_packet) - 4); 1602 1603 /* Skip padding. */ 1604 if ((r = sshbuf_consume(state->incoming_packet, 8 - len % 8)) != 0) 1605 goto out; 1606 1607 /* Test check bytes. */ 1608 if (len != sshbuf_len(state->incoming_packet)) { 1609 error("%s: len %d != sshbuf_len %zd", __func__, 1610 len, sshbuf_len(state->incoming_packet)); 1611 if ((r = sshpkt_disconnect(ssh, "invalid packet length")) != 0 || 1612 (r = ssh_packet_write_wait(ssh)) < 0) 1613 return r; 1614 return SSH_ERR_CONN_CORRUPT; 1615 } 1616 1617 cp = sshbuf_ptr(state->incoming_packet) + len - 4; 1618 stored_checksum = PEEK_U32(cp); 1619 if (checksum != stored_checksum) { 1620 error("Corrupted check bytes on input"); 1621 if ((r = sshpkt_disconnect(ssh, "connection corrupted")) != 0 || 1622 (r = ssh_packet_write_wait(ssh)) < 0) 1623 return r; 1624 return SSH_ERR_CONN_CORRUPT; 1625 } 1626 if ((r = sshbuf_consume_end(state->incoming_packet, 4)) < 0) 1627 goto out; 1628 1629 if (state->packet_compression) { 1630 sshbuf_reset(state->compression_buffer); 1631 if ((r = uncompress_buffer(ssh, state->incoming_packet, 1632 state->compression_buffer)) != 0) 1633 goto out; 1634 sshbuf_reset(state->incoming_packet); 1635 if ((r = sshbuf_putb(state->incoming_packet, 1636 state->compression_buffer)) != 0) 1637 goto out; 1638 } 1639 state->p_read.packets++; 1640 state->p_read.bytes += padded_len + 4; 1641 if ((r = sshbuf_get_u8(state->incoming_packet, typep)) != 0) 1642 goto out; 1643 if (*typep < SSH_MSG_MIN || *typep > SSH_MSG_MAX) { 1644 error("Invalid ssh1 packet type: %d", *typep); 1645 if ((r = sshpkt_disconnect(ssh, "invalid packet type")) != 0 || 1646 (r = ssh_packet_write_wait(ssh)) < 0) 1647 return r; 1648 return SSH_ERR_PROTOCOL_ERROR; 1649 } 1650 r = 0; 1651 out: 1652 return r; 1653 } 1654 1655 static int 1656 ssh_packet_read_poll2_mux(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1657 { 1658 struct session_state *state = ssh->state; 1659 const u_char *cp; 1660 size_t need; 1661 int r; 1662 1663 if (ssh->kex) 1664 return SSH_ERR_INTERNAL_ERROR; 1665 *typep = SSH_MSG_NONE; 1666 cp = sshbuf_ptr(state->input); 1667 if (state->packlen == 0) { 1668 if (sshbuf_len(state->input) < 4 + 1) 1669 return 0; /* packet is incomplete */ 1670 state->packlen = PEEK_U32(cp); 1671 if (state->packlen < 4 + 1 || 1672 state->packlen > PACKET_MAX_SIZE) 1673 return SSH_ERR_MESSAGE_INCOMPLETE; 1674 } 1675 need = state->packlen + 4; 1676 if (sshbuf_len(state->input) < need) 1677 return 0; /* packet is incomplete */ 1678 sshbuf_reset(state->incoming_packet); 1679 if ((r = sshbuf_put(state->incoming_packet, cp + 4, 1680 state->packlen)) != 0 || 1681 (r = sshbuf_consume(state->input, need)) != 0 || 1682 (r = sshbuf_get_u8(state->incoming_packet, NULL)) != 0 || 1683 (r = sshbuf_get_u8(state->incoming_packet, typep)) != 0) 1684 return r; 1685 if (ssh_packet_log_type(*typep)) 1686 debug3("%s: type %u", __func__, *typep); 1687 /* sshbuf_dump(state->incoming_packet, stderr); */ 1688 /* reset for next packet */ 1689 state->packlen = 0; 1690 return r; 1691 } 1692 1693 int 1694 ssh_packet_read_poll2(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1695 { 1696 struct session_state *state = ssh->state; 1697 u_int padlen, need; 1698 u_char *cp; 1699 u_int maclen, aadlen = 0, authlen = 0, block_size; 1700 struct sshenc *enc = NULL; 1701 struct sshmac *mac = NULL; 1702 struct sshcomp *comp = NULL; 1703 int r; 1704 1705 if (state->mux) 1706 return ssh_packet_read_poll2_mux(ssh, typep, seqnr_p); 1707 1708 *typep = SSH_MSG_NONE; 1709 1710 if (state->packet_discard) 1711 return 0; 1712 1713 if (state->newkeys[MODE_IN] != NULL) { 1714 enc = &state->newkeys[MODE_IN]->enc; 1715 mac = &state->newkeys[MODE_IN]->mac; 1716 comp = &state->newkeys[MODE_IN]->comp; 1717 /* disable mac for authenticated encryption */ 1718 if ((authlen = cipher_authlen(enc->cipher)) != 0) 1719 mac = NULL; 1720 } 1721 maclen = mac && mac->enabled ? mac->mac_len : 0; 1722 block_size = enc ? enc->block_size : 8; 1723 aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0; 1724 1725 if (aadlen && state->packlen == 0) { 1726 if (cipher_get_length(state->receive_context, 1727 &state->packlen, state->p_read.seqnr, 1728 sshbuf_ptr(state->input), sshbuf_len(state->input)) != 0) 1729 return 0; 1730 if (state->packlen < 1 + 4 || 1731 state->packlen > PACKET_MAX_SIZE) { 1732 #ifdef PACKET_DEBUG 1733 sshbuf_dump(state->input, stderr); 1734 #endif 1735 logit("Bad packet length %u.", state->packlen); 1736 if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0) 1737 return r; 1738 return SSH_ERR_CONN_CORRUPT; 1739 } 1740 sshbuf_reset(state->incoming_packet); 1741 } else if (state->packlen == 0) { 1742 /* 1743 * check if input size is less than the cipher block size, 1744 * decrypt first block and extract length of incoming packet 1745 */ 1746 if (sshbuf_len(state->input) < block_size) 1747 return 0; 1748 sshbuf_reset(state->incoming_packet); 1749 if ((r = sshbuf_reserve(state->incoming_packet, block_size, 1750 &cp)) != 0) 1751 goto out; 1752 if ((r = cipher_crypt(state->receive_context, 1753 state->p_send.seqnr, cp, sshbuf_ptr(state->input), 1754 block_size, 0, 0)) != 0) 1755 goto out; 1756 state->packlen = PEEK_U32(sshbuf_ptr(state->incoming_packet)); 1757 if (state->packlen < 1 + 4 || 1758 state->packlen > PACKET_MAX_SIZE) { 1759 #ifdef PACKET_DEBUG 1760 fprintf(stderr, "input: \n"); 1761 sshbuf_dump(state->input, stderr); 1762 fprintf(stderr, "incoming_packet: \n"); 1763 sshbuf_dump(state->incoming_packet, stderr); 1764 #endif 1765 logit("Bad packet length %u.", state->packlen); 1766 return ssh_packet_start_discard(ssh, enc, mac, 0, 1767 PACKET_MAX_SIZE); 1768 } 1769 if ((r = sshbuf_consume(state->input, block_size)) != 0) 1770 goto out; 1771 } 1772 DBG(debug("input: packet len %u", state->packlen+4)); 1773 1774 if (aadlen) { 1775 /* only the payload is encrypted */ 1776 need = state->packlen; 1777 } else { 1778 /* 1779 * the payload size and the payload are encrypted, but we 1780 * have a partial packet of block_size bytes 1781 */ 1782 need = 4 + state->packlen - block_size; 1783 } 1784 DBG(debug("partial packet: block %d, need %d, maclen %d, authlen %d," 1785 " aadlen %d", block_size, need, maclen, authlen, aadlen)); 1786 if (need % block_size != 0) { 1787 logit("padding error: need %d block %d mod %d", 1788 need, block_size, need % block_size); 1789 return ssh_packet_start_discard(ssh, enc, mac, 0, 1790 PACKET_MAX_SIZE - block_size); 1791 } 1792 /* 1793 * check if the entire packet has been received and 1794 * decrypt into incoming_packet: 1795 * 'aadlen' bytes are unencrypted, but authenticated. 1796 * 'need' bytes are encrypted, followed by either 1797 * 'authlen' bytes of authentication tag or 1798 * 'maclen' bytes of message authentication code. 1799 */ 1800 if (sshbuf_len(state->input) < aadlen + need + authlen + maclen) 1801 return 0; /* packet is incomplete */ 1802 #ifdef PACKET_DEBUG 1803 fprintf(stderr, "read_poll enc/full: "); 1804 sshbuf_dump(state->input, stderr); 1805 #endif 1806 /* EtM: check mac over encrypted input */ 1807 if (mac && mac->enabled && mac->etm) { 1808 if ((r = mac_check(mac, state->p_read.seqnr, 1809 sshbuf_ptr(state->input), aadlen + need, 1810 sshbuf_ptr(state->input) + aadlen + need + authlen, 1811 maclen)) != 0) { 1812 if (r == SSH_ERR_MAC_INVALID) 1813 logit("Corrupted MAC on input."); 1814 goto out; 1815 } 1816 } 1817 if ((r = sshbuf_reserve(state->incoming_packet, aadlen + need, 1818 &cp)) != 0) 1819 goto out; 1820 if ((r = cipher_crypt(state->receive_context, state->p_read.seqnr, cp, 1821 sshbuf_ptr(state->input), need, aadlen, authlen)) != 0) 1822 goto out; 1823 if ((r = sshbuf_consume(state->input, aadlen + need + authlen)) != 0) 1824 goto out; 1825 if (mac && mac->enabled) { 1826 /* Not EtM: check MAC over cleartext */ 1827 if (!mac->etm && (r = mac_check(mac, state->p_read.seqnr, 1828 sshbuf_ptr(state->incoming_packet), 1829 sshbuf_len(state->incoming_packet), 1830 sshbuf_ptr(state->input), maclen)) != 0) { 1831 if (r != SSH_ERR_MAC_INVALID) 1832 goto out; 1833 logit("Corrupted MAC on input."); 1834 if (need > PACKET_MAX_SIZE) 1835 return SSH_ERR_INTERNAL_ERROR; 1836 return ssh_packet_start_discard(ssh, enc, mac, 1837 sshbuf_len(state->incoming_packet), 1838 PACKET_MAX_SIZE - need); 1839 } 1840 /* Remove MAC from input buffer */ 1841 DBG(debug("MAC #%d ok", state->p_read.seqnr)); 1842 if ((r = sshbuf_consume(state->input, mac->mac_len)) != 0) 1843 goto out; 1844 } 1845 if (seqnr_p != NULL) 1846 *seqnr_p = state->p_read.seqnr; 1847 if (++state->p_read.seqnr == 0) 1848 logit("incoming seqnr wraps around"); 1849 if (++state->p_read.packets == 0) 1850 if (!(ssh->compat & SSH_BUG_NOREKEY)) 1851 return SSH_ERR_NEED_REKEY; 1852 state->p_read.blocks += (state->packlen + 4) / block_size; 1853 state->p_read.bytes += state->packlen + 4; 1854 1855 /* get padlen */ 1856 padlen = sshbuf_ptr(state->incoming_packet)[4]; 1857 DBG(debug("input: padlen %d", padlen)); 1858 if (padlen < 4) { 1859 if ((r = sshpkt_disconnect(ssh, 1860 "Corrupted padlen %d on input.", padlen)) != 0 || 1861 (r = ssh_packet_write_wait(ssh)) < 0) 1862 return r; 1863 return SSH_ERR_CONN_CORRUPT; 1864 } 1865 1866 /* skip packet size + padlen, discard padding */ 1867 if ((r = sshbuf_consume(state->incoming_packet, 4 + 1)) != 0 || 1868 ((r = sshbuf_consume_end(state->incoming_packet, padlen)) != 0)) 1869 goto out; 1870 1871 DBG(debug("input: len before de-compress %zd", 1872 sshbuf_len(state->incoming_packet))); 1873 if (comp && comp->enabled) { 1874 sshbuf_reset(state->compression_buffer); 1875 if ((r = uncompress_buffer(ssh, state->incoming_packet, 1876 state->compression_buffer)) != 0) 1877 goto out; 1878 sshbuf_reset(state->incoming_packet); 1879 if ((r = sshbuf_putb(state->incoming_packet, 1880 state->compression_buffer)) != 0) 1881 goto out; 1882 DBG(debug("input: len after de-compress %zd", 1883 sshbuf_len(state->incoming_packet))); 1884 } 1885 /* 1886 * get packet type, implies consume. 1887 * return length of payload (without type field) 1888 */ 1889 if ((r = sshbuf_get_u8(state->incoming_packet, typep)) != 0) 1890 goto out; 1891 if (ssh_packet_log_type(*typep)) 1892 debug3("receive packet: type %u", *typep); 1893 if (*typep < SSH2_MSG_MIN || *typep >= SSH2_MSG_LOCAL_MIN) { 1894 if ((r = sshpkt_disconnect(ssh, 1895 "Invalid ssh2 packet type: %d", *typep)) != 0 || 1896 (r = ssh_packet_write_wait(ssh)) < 0) 1897 return r; 1898 return SSH_ERR_PROTOCOL_ERROR; 1899 } 1900 if (state->hook_in != NULL && 1901 (r = state->hook_in(ssh, state->incoming_packet, typep, 1902 state->hook_in_ctx)) != 0) 1903 return r; 1904 if (*typep == SSH2_MSG_USERAUTH_SUCCESS && !state->server_side) 1905 r = ssh_packet_enable_delayed_compress(ssh); 1906 else 1907 r = 0; 1908 #ifdef PACKET_DEBUG 1909 fprintf(stderr, "read/plain[%d]:\r\n", *typep); 1910 sshbuf_dump(state->incoming_packet, stderr); 1911 #endif 1912 /* reset for next packet */ 1913 state->packlen = 0; 1914 1915 /* do we need to rekey? */ 1916 if (ssh_packet_need_rekeying(ssh, 0)) { 1917 debug3("%s: rekex triggered", __func__); 1918 if ((r = kex_start_rekex(ssh)) != 0) 1919 return r; 1920 } 1921 out: 1922 return r; 1923 } 1924 1925 int 1926 ssh_packet_read_poll_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1927 { 1928 struct session_state *state = ssh->state; 1929 u_int reason, seqnr; 1930 int r; 1931 u_char *msg; 1932 1933 for (;;) { 1934 msg = NULL; 1935 if (compat20) { 1936 r = ssh_packet_read_poll2(ssh, typep, seqnr_p); 1937 if (r != 0) 1938 return r; 1939 if (*typep) { 1940 state->keep_alive_timeouts = 0; 1941 DBG(debug("received packet type %d", *typep)); 1942 } 1943 switch (*typep) { 1944 case SSH2_MSG_IGNORE: 1945 debug3("Received SSH2_MSG_IGNORE"); 1946 break; 1947 case SSH2_MSG_DEBUG: 1948 if ((r = sshpkt_get_u8(ssh, NULL)) != 0 || 1949 (r = sshpkt_get_string(ssh, &msg, NULL)) != 0 || 1950 (r = sshpkt_get_string(ssh, NULL, NULL)) != 0) { 1951 free(msg); 1952 return r; 1953 } 1954 debug("Remote: %.900s", msg); 1955 free(msg); 1956 break; 1957 case SSH2_MSG_DISCONNECT: 1958 if ((r = sshpkt_get_u32(ssh, &reason)) != 0 || 1959 (r = sshpkt_get_string(ssh, &msg, NULL)) != 0) 1960 return r; 1961 /* Ignore normal client exit notifications */ 1962 do_log2(ssh->state->server_side && 1963 reason == SSH2_DISCONNECT_BY_APPLICATION ? 1964 SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_ERROR, 1965 "Received disconnect from %s port %d:" 1966 "%u: %.400s", ssh_remote_ipaddr(ssh), 1967 ssh_remote_port(ssh), reason, msg); 1968 free(msg); 1969 return SSH_ERR_DISCONNECTED; 1970 case SSH2_MSG_UNIMPLEMENTED: 1971 if ((r = sshpkt_get_u32(ssh, &seqnr)) != 0) 1972 return r; 1973 debug("Received SSH2_MSG_UNIMPLEMENTED for %u", 1974 seqnr); 1975 break; 1976 default: 1977 return 0; 1978 } 1979 } else { 1980 r = ssh_packet_read_poll1(ssh, typep); 1981 switch (*typep) { 1982 case SSH_MSG_NONE: 1983 return SSH_MSG_NONE; 1984 case SSH_MSG_IGNORE: 1985 break; 1986 case SSH_MSG_DEBUG: 1987 if ((r = sshpkt_get_string(ssh, &msg, NULL)) != 0) 1988 return r; 1989 debug("Remote: %.900s", msg); 1990 free(msg); 1991 break; 1992 case SSH_MSG_DISCONNECT: 1993 if ((r = sshpkt_get_string(ssh, &msg, NULL)) != 0) 1994 return r; 1995 error("Received disconnect from %s port %d: " 1996 "%.400s", ssh_remote_ipaddr(ssh), 1997 ssh_remote_port(ssh), msg); 1998 free(msg); 1999 return SSH_ERR_DISCONNECTED; 2000 default: 2001 DBG(debug("received packet type %d", *typep)); 2002 return 0; 2003 } 2004 } 2005 } 2006 } 2007 2008 /* 2009 * Buffers the given amount of input characters. This is intended to be used 2010 * together with packet_read_poll. 2011 */ 2012 2013 int 2014 ssh_packet_process_incoming(struct ssh *ssh, const char *buf, u_int len) 2015 { 2016 struct session_state *state = ssh->state; 2017 int r; 2018 2019 if (state->packet_discard) { 2020 state->keep_alive_timeouts = 0; /* ?? */ 2021 if (len >= state->packet_discard) { 2022 if ((r = ssh_packet_stop_discard(ssh)) != 0) 2023 return r; 2024 } 2025 state->packet_discard -= len; 2026 return 0; 2027 } 2028 if ((r = sshbuf_put(ssh->state->input, buf, len)) != 0) 2029 return r; 2030 2031 return 0; 2032 } 2033 2034 int 2035 ssh_packet_remaining(struct ssh *ssh) 2036 { 2037 return sshbuf_len(ssh->state->incoming_packet); 2038 } 2039 2040 /* 2041 * Sends a diagnostic message from the server to the client. This message 2042 * can be sent at any time (but not while constructing another message). The 2043 * message is printed immediately, but only if the client is being executed 2044 * in verbose mode. These messages are primarily intended to ease debugging 2045 * authentication problems. The length of the formatted message must not 2046 * exceed 1024 bytes. This will automatically call ssh_packet_write_wait. 2047 */ 2048 void 2049 ssh_packet_send_debug(struct ssh *ssh, const char *fmt,...) 2050 { 2051 char buf[1024]; 2052 va_list args; 2053 int r; 2054 2055 if (compat20 && (ssh->compat & SSH_BUG_DEBUG)) 2056 return; 2057 2058 va_start(args, fmt); 2059 vsnprintf(buf, sizeof(buf), fmt, args); 2060 va_end(args); 2061 2062 if (compat20) { 2063 if ((r = sshpkt_start(ssh, SSH2_MSG_DEBUG)) != 0 || 2064 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* always display */ 2065 (r = sshpkt_put_cstring(ssh, buf)) != 0 || 2066 (r = sshpkt_put_cstring(ssh, "")) != 0 || 2067 (r = sshpkt_send(ssh)) != 0) 2068 fatal("%s: %s", __func__, ssh_err(r)); 2069 } else { 2070 if ((r = sshpkt_start(ssh, SSH_MSG_DEBUG)) != 0 || 2071 (r = sshpkt_put_cstring(ssh, buf)) != 0 || 2072 (r = sshpkt_send(ssh)) != 0) 2073 fatal("%s: %s", __func__, ssh_err(r)); 2074 } 2075 if ((r = ssh_packet_write_wait(ssh)) < 0) 2076 fatal("%s: %s", __func__, ssh_err(r)); 2077 } 2078 2079 /* 2080 * Pretty-print connection-terminating errors and exit. 2081 */ 2082 void 2083 sshpkt_fatal(struct ssh *ssh, const char *tag, int r) 2084 { 2085 switch (r) { 2086 case SSH_ERR_CONN_CLOSED: 2087 logdie("Connection closed by %.200s port %d", 2088 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 2089 case SSH_ERR_CONN_TIMEOUT: 2090 logdie("Connection %s %.200s port %d timed out", 2091 ssh->state->server_side ? "from" : "to", 2092 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 2093 case SSH_ERR_DISCONNECTED: 2094 logdie("Disconnected from %.200s port %d", 2095 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 2096 case SSH_ERR_SYSTEM_ERROR: 2097 if (errno == ECONNRESET) 2098 logdie("Connection reset by %.200s port %d", 2099 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 2100 /* FALLTHROUGH */ 2101 case SSH_ERR_NO_CIPHER_ALG_MATCH: 2102 case SSH_ERR_NO_MAC_ALG_MATCH: 2103 case SSH_ERR_NO_COMPRESS_ALG_MATCH: 2104 case SSH_ERR_NO_KEX_ALG_MATCH: 2105 case SSH_ERR_NO_HOSTKEY_ALG_MATCH: 2106 if (ssh && ssh->kex && ssh->kex->failed_choice) { 2107 logdie("Unable to negotiate with %.200s port %d: %s. " 2108 "Their offer: %s", ssh_remote_ipaddr(ssh), 2109 ssh_remote_port(ssh), ssh_err(r), 2110 ssh->kex->failed_choice); 2111 } 2112 /* FALLTHROUGH */ 2113 default: 2114 logdie("%s%sConnection %s %.200s port %d: %s", 2115 tag != NULL ? tag : "", tag != NULL ? ": " : "", 2116 ssh->state->server_side ? "from" : "to", 2117 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), ssh_err(r)); 2118 } 2119 } 2120 2121 /* 2122 * Logs the error plus constructs and sends a disconnect packet, closes the 2123 * connection, and exits. This function never returns. The error message 2124 * should not contain a newline. The length of the formatted message must 2125 * not exceed 1024 bytes. 2126 */ 2127 void 2128 ssh_packet_disconnect(struct ssh *ssh, const char *fmt,...) 2129 { 2130 char buf[1024]; 2131 va_list args; 2132 static int disconnecting = 0; 2133 int r; 2134 2135 if (disconnecting) /* Guard against recursive invocations. */ 2136 fatal("packet_disconnect called recursively."); 2137 disconnecting = 1; 2138 2139 /* 2140 * Format the message. Note that the caller must make sure the 2141 * message is of limited size. 2142 */ 2143 va_start(args, fmt); 2144 vsnprintf(buf, sizeof(buf), fmt, args); 2145 va_end(args); 2146 2147 /* Display the error locally */ 2148 logit("Disconnecting: %.100s", buf); 2149 2150 /* 2151 * Send the disconnect message to the other side, and wait 2152 * for it to get sent. 2153 */ 2154 if ((r = sshpkt_disconnect(ssh, "%s", buf)) != 0) 2155 sshpkt_fatal(ssh, __func__, r); 2156 2157 if ((r = ssh_packet_write_wait(ssh)) < 0) 2158 sshpkt_fatal(ssh, __func__, r); 2159 2160 /* Close the connection. */ 2161 ssh_packet_close(ssh); 2162 cleanup_exit(255); 2163 } 2164 2165 /* 2166 * Checks if there is any buffered output, and tries to write some of 2167 * the output. 2168 */ 2169 int 2170 ssh_packet_write_poll(struct ssh *ssh) 2171 { 2172 struct session_state *state = ssh->state; 2173 int len = sshbuf_len(state->output); 2174 int r; 2175 2176 if (len > 0) { 2177 len = write(state->connection_out, 2178 sshbuf_ptr(state->output), len); 2179 if (len == -1) { 2180 if (errno == EINTR || errno == EAGAIN) 2181 return 0; 2182 return SSH_ERR_SYSTEM_ERROR; 2183 } 2184 if (len == 0) 2185 return SSH_ERR_CONN_CLOSED; 2186 if ((r = sshbuf_consume(state->output, len)) < 0) 2187 return r; 2188 } 2189 return len; 2190 } 2191 2192 /* 2193 * Calls packet_write_poll repeatedly until all pending output data has been 2194 * written. 2195 */ 2196 int 2197 ssh_packet_write_wait(struct ssh *ssh) 2198 { 2199 fd_set *setp; 2200 int ret, r, ms_remain = 0; 2201 struct timeval start, timeout, *timeoutp = NULL; 2202 u_int bytes_sent = 0; 2203 struct session_state *state = ssh->state; 2204 2205 setp = calloc(howmany(state->connection_out + 1, 2206 NFDBITS), sizeof(fd_mask)); 2207 if (setp == NULL) 2208 return SSH_ERR_ALLOC_FAIL; 2209 2210 if ((r = ssh_packet_write_poll(ssh)) < 0) { 2211 free(setp); 2212 return r; 2213 } 2214 bytes_sent += r; 2215 2216 while (ssh_packet_have_data_to_write(ssh)) { 2217 memset(setp, 0, howmany(state->connection_out + 1, 2218 NFDBITS) * sizeof(fd_mask)); 2219 FD_SET(state->connection_out, setp); 2220 2221 if (state->packet_timeout_ms > 0) { 2222 ms_remain = state->packet_timeout_ms; 2223 timeoutp = &timeout; 2224 } 2225 for (;;) { 2226 if (state->packet_timeout_ms != -1) { 2227 ms_to_timeval(&timeout, ms_remain); 2228 gettimeofday(&start, NULL); 2229 } 2230 if ((ret = select(state->connection_out + 1, 2231 NULL, setp, NULL, timeoutp)) >= 0) 2232 break; 2233 if (errno != EAGAIN && errno != EINTR) 2234 break; 2235 if (state->packet_timeout_ms == -1) 2236 continue; 2237 ms_subtract_diff(&start, &ms_remain); 2238 if (ms_remain <= 0) { 2239 ret = 0; 2240 break; 2241 } 2242 } 2243 if (ret == 0) { 2244 free(setp); 2245 return SSH_ERR_CONN_TIMEOUT; 2246 } 2247 if ((r = ssh_packet_write_poll(ssh)) < 0) { 2248 free(setp); 2249 return r; 2250 } 2251 bytes_sent += r; 2252 } 2253 free(setp); 2254 return bytes_sent; 2255 } 2256 2257 /* Returns true if there is buffered data to write to the connection. */ 2258 2259 int 2260 ssh_packet_have_data_to_write(struct ssh *ssh) 2261 { 2262 return sshbuf_len(ssh->state->output) != 0; 2263 } 2264 2265 /* Returns true if there is not too much data to write to the connection. */ 2266 2267 int 2268 ssh_packet_not_very_much_data_to_write(struct ssh *ssh) 2269 { 2270 if (ssh->state->interactive_mode) 2271 return sshbuf_len(ssh->state->output) < 16384; 2272 else 2273 return sshbuf_len(ssh->state->output) < 128 * 1024; 2274 } 2275 2276 void 2277 ssh_packet_set_tos(struct ssh *ssh, int tos) 2278 { 2279 if (!ssh_packet_connection_is_on_socket(ssh)) 2280 return; 2281 switch (ssh_packet_connection_af(ssh)) { 2282 case AF_INET: 2283 debug3("%s: set IP_TOS 0x%02x", __func__, tos); 2284 if (setsockopt(ssh->state->connection_in, 2285 IPPROTO_IP, IP_TOS, &tos, sizeof(tos)) < 0) 2286 error("setsockopt IP_TOS %d: %.100s:", 2287 tos, strerror(errno)); 2288 break; 2289 case AF_INET6: 2290 debug3("%s: set IPV6_TCLASS 0x%02x", __func__, tos); 2291 if (setsockopt(ssh->state->connection_in, 2292 IPPROTO_IPV6, IPV6_TCLASS, &tos, sizeof(tos)) < 0) 2293 error("setsockopt IPV6_TCLASS %d: %.100s:", 2294 tos, strerror(errno)); 2295 break; 2296 } 2297 } 2298 2299 /* Informs that the current session is interactive. Sets IP flags for that. */ 2300 2301 void 2302 ssh_packet_set_interactive(struct ssh *ssh, int interactive, int qos_interactive, int qos_bulk) 2303 { 2304 struct session_state *state = ssh->state; 2305 2306 if (state->set_interactive_called) 2307 return; 2308 state->set_interactive_called = 1; 2309 2310 /* Record that we are in interactive mode. */ 2311 state->interactive_mode = interactive; 2312 2313 /* Only set socket options if using a socket. */ 2314 if (!ssh_packet_connection_is_on_socket(ssh)) 2315 return; 2316 set_nodelay(state->connection_in); 2317 ssh_packet_set_tos(ssh, interactive ? qos_interactive : 2318 qos_bulk); 2319 } 2320 2321 /* Returns true if the current connection is interactive. */ 2322 2323 int 2324 ssh_packet_is_interactive(struct ssh *ssh) 2325 { 2326 return ssh->state->interactive_mode; 2327 } 2328 2329 int 2330 ssh_packet_set_maxsize(struct ssh *ssh, u_int s) 2331 { 2332 struct session_state *state = ssh->state; 2333 2334 if (state->set_maxsize_called) { 2335 logit("packet_set_maxsize: called twice: old %d new %d", 2336 state->max_packet_size, s); 2337 return -1; 2338 } 2339 if (s < 4 * 1024 || s > 1024 * 1024) { 2340 logit("packet_set_maxsize: bad size %d", s); 2341 return -1; 2342 } 2343 state->set_maxsize_called = 1; 2344 debug("packet_set_maxsize: setting to %d", s); 2345 state->max_packet_size = s; 2346 return s; 2347 } 2348 2349 int 2350 ssh_packet_inc_alive_timeouts(struct ssh *ssh) 2351 { 2352 return ++ssh->state->keep_alive_timeouts; 2353 } 2354 2355 void 2356 ssh_packet_set_alive_timeouts(struct ssh *ssh, int ka) 2357 { 2358 ssh->state->keep_alive_timeouts = ka; 2359 } 2360 2361 u_int 2362 ssh_packet_get_maxsize(struct ssh *ssh) 2363 { 2364 return ssh->state->max_packet_size; 2365 } 2366 2367 /* 2368 * 9.2. Ignored Data Message 2369 * 2370 * byte SSH_MSG_IGNORE 2371 * string data 2372 * 2373 * All implementations MUST understand (and ignore) this message at any 2374 * time (after receiving the protocol version). No implementation is 2375 * required to send them. This message can be used as an additional 2376 * protection measure against advanced traffic analysis techniques. 2377 */ 2378 void 2379 ssh_packet_send_ignore(struct ssh *ssh, int nbytes) 2380 { 2381 u_int32_t rnd = 0; 2382 int r, i; 2383 2384 if ((r = sshpkt_start(ssh, compat20 ? 2385 SSH2_MSG_IGNORE : SSH_MSG_IGNORE)) != 0 || 2386 (r = sshpkt_put_u32(ssh, nbytes)) != 0) 2387 fatal("%s: %s", __func__, ssh_err(r)); 2388 for (i = 0; i < nbytes; i++) { 2389 if (i % 4 == 0) 2390 rnd = arc4random(); 2391 if ((r = sshpkt_put_u8(ssh, (u_char)rnd & 0xff)) != 0) 2392 fatal("%s: %s", __func__, ssh_err(r)); 2393 rnd >>= 8; 2394 } 2395 } 2396 2397 void 2398 ssh_packet_set_rekey_limits(struct ssh *ssh, u_int64_t bytes, time_t seconds) 2399 { 2400 debug3("rekey after %llu bytes, %d seconds", (unsigned long long)bytes, 2401 (int)seconds); 2402 ssh->state->rekey_limit = bytes; 2403 ssh->state->rekey_interval = seconds; 2404 } 2405 2406 time_t 2407 ssh_packet_get_rekey_timeout(struct ssh *ssh) 2408 { 2409 time_t seconds; 2410 2411 seconds = ssh->state->rekey_time + ssh->state->rekey_interval - 2412 monotime(); 2413 return (seconds <= 0 ? 1 : seconds); 2414 } 2415 2416 void 2417 ssh_packet_set_server(struct ssh *ssh) 2418 { 2419 ssh->state->server_side = 1; 2420 } 2421 2422 void 2423 ssh_packet_set_authenticated(struct ssh *ssh) 2424 { 2425 ssh->state->after_authentication = 1; 2426 } 2427 2428 void * 2429 ssh_packet_get_input(struct ssh *ssh) 2430 { 2431 return (void *)ssh->state->input; 2432 } 2433 2434 void * 2435 ssh_packet_get_output(struct ssh *ssh) 2436 { 2437 return (void *)ssh->state->output; 2438 } 2439 2440 /* Reset after_authentication and reset compression in post-auth privsep */ 2441 static int 2442 ssh_packet_set_postauth(struct ssh *ssh) 2443 { 2444 int r; 2445 2446 debug("%s: called", __func__); 2447 /* This was set in net child, but is not visible in user child */ 2448 ssh->state->after_authentication = 1; 2449 ssh->state->rekeying = 0; 2450 if ((r = ssh_packet_enable_delayed_compress(ssh)) != 0) 2451 return r; 2452 return 0; 2453 } 2454 2455 /* Packet state (de-)serialization for privsep */ 2456 2457 /* turn kex into a blob for packet state serialization */ 2458 static int 2459 kex_to_blob(struct sshbuf *m, struct kex *kex) 2460 { 2461 int r; 2462 2463 if ((r = sshbuf_put_string(m, kex->session_id, 2464 kex->session_id_len)) != 0 || 2465 (r = sshbuf_put_u32(m, kex->we_need)) != 0 || 2466 (r = sshbuf_put_u32(m, kex->hostkey_type)) != 0 || 2467 (r = sshbuf_put_u32(m, kex->kex_type)) != 0 || 2468 (r = sshbuf_put_stringb(m, kex->my)) != 0 || 2469 (r = sshbuf_put_stringb(m, kex->peer)) != 0 || 2470 (r = sshbuf_put_u32(m, kex->flags)) != 0 || 2471 (r = sshbuf_put_cstring(m, kex->client_version_string)) != 0 || 2472 (r = sshbuf_put_cstring(m, kex->server_version_string)) != 0) 2473 return r; 2474 return 0; 2475 } 2476 2477 /* turn key exchange results into a blob for packet state serialization */ 2478 static int 2479 newkeys_to_blob(struct sshbuf *m, struct ssh *ssh, int mode) 2480 { 2481 struct sshbuf *b; 2482 struct sshcipher_ctx *cc; 2483 struct sshcomp *comp; 2484 struct sshenc *enc; 2485 struct sshmac *mac; 2486 struct newkeys *newkey; 2487 int r; 2488 2489 if ((newkey = ssh->state->newkeys[mode]) == NULL) 2490 return SSH_ERR_INTERNAL_ERROR; 2491 enc = &newkey->enc; 2492 mac = &newkey->mac; 2493 comp = &newkey->comp; 2494 cc = (mode == MODE_OUT) ? ssh->state->send_context : 2495 ssh->state->receive_context; 2496 if ((r = cipher_get_keyiv(cc, enc->iv, enc->iv_len)) != 0) 2497 return r; 2498 if ((b = sshbuf_new()) == NULL) 2499 return SSH_ERR_ALLOC_FAIL; 2500 /* The cipher struct is constant and shared, you export pointer */ 2501 if ((r = sshbuf_put_cstring(b, enc->name)) != 0 || 2502 (r = sshbuf_put(b, &enc->cipher, sizeof(enc->cipher))) != 0 || 2503 (r = sshbuf_put_u32(b, enc->enabled)) != 0 || 2504 (r = sshbuf_put_u32(b, enc->block_size)) != 0 || 2505 (r = sshbuf_put_string(b, enc->key, enc->key_len)) != 0 || 2506 (r = sshbuf_put_string(b, enc->iv, enc->iv_len)) != 0) 2507 goto out; 2508 if (cipher_authlen(enc->cipher) == 0) { 2509 if ((r = sshbuf_put_cstring(b, mac->name)) != 0 || 2510 (r = sshbuf_put_u32(b, mac->enabled)) != 0 || 2511 (r = sshbuf_put_string(b, mac->key, mac->key_len)) != 0) 2512 goto out; 2513 } 2514 if ((r = sshbuf_put_u32(b, comp->type)) != 0 || 2515 (r = sshbuf_put_cstring(b, comp->name)) != 0) 2516 goto out; 2517 r = sshbuf_put_stringb(m, b); 2518 out: 2519 sshbuf_free(b); 2520 return r; 2521 } 2522 2523 /* serialize packet state into a blob */ 2524 int 2525 ssh_packet_get_state(struct ssh *ssh, struct sshbuf *m) 2526 { 2527 struct session_state *state = ssh->state; 2528 u_char *p; 2529 size_t slen, rlen; 2530 int r, ssh1cipher; 2531 2532 if (!compat20) { 2533 ssh1cipher = cipher_ctx_get_number(state->receive_context); 2534 slen = cipher_get_keyiv_len(state->send_context); 2535 rlen = cipher_get_keyiv_len(state->receive_context); 2536 if ((r = sshbuf_put_u32(m, state->remote_protocol_flags)) != 0 || 2537 (r = sshbuf_put_u32(m, ssh1cipher)) != 0 || 2538 (r = sshbuf_put_string(m, state->ssh1_key, state->ssh1_keylen)) != 0 || 2539 (r = sshbuf_put_u32(m, slen)) != 0 || 2540 (r = sshbuf_reserve(m, slen, &p)) != 0 || 2541 (r = cipher_get_keyiv(state->send_context, p, slen)) != 0 || 2542 (r = sshbuf_put_u32(m, rlen)) != 0 || 2543 (r = sshbuf_reserve(m, rlen, &p)) != 0 || 2544 (r = cipher_get_keyiv(state->receive_context, p, rlen)) != 0) 2545 return r; 2546 } else { 2547 if ((r = kex_to_blob(m, ssh->kex)) != 0 || 2548 (r = newkeys_to_blob(m, ssh, MODE_OUT)) != 0 || 2549 (r = newkeys_to_blob(m, ssh, MODE_IN)) != 0 || 2550 (r = sshbuf_put_u64(m, state->rekey_limit)) != 0 || 2551 (r = sshbuf_put_u32(m, state->rekey_interval)) != 0 || 2552 (r = sshbuf_put_u32(m, state->p_send.seqnr)) != 0 || 2553 (r = sshbuf_put_u64(m, state->p_send.blocks)) != 0 || 2554 (r = sshbuf_put_u32(m, state->p_send.packets)) != 0 || 2555 (r = sshbuf_put_u64(m, state->p_send.bytes)) != 0 || 2556 (r = sshbuf_put_u32(m, state->p_read.seqnr)) != 0 || 2557 (r = sshbuf_put_u64(m, state->p_read.blocks)) != 0 || 2558 (r = sshbuf_put_u32(m, state->p_read.packets)) != 0 || 2559 (r = sshbuf_put_u64(m, state->p_read.bytes)) != 0) 2560 return r; 2561 } 2562 2563 slen = cipher_get_keycontext(state->send_context, NULL); 2564 rlen = cipher_get_keycontext(state->receive_context, NULL); 2565 if ((r = sshbuf_put_u32(m, slen)) != 0 || 2566 (r = sshbuf_reserve(m, slen, &p)) != 0) 2567 return r; 2568 if (cipher_get_keycontext(state->send_context, p) != (int)slen) 2569 return SSH_ERR_INTERNAL_ERROR; 2570 if ((r = sshbuf_put_u32(m, rlen)) != 0 || 2571 (r = sshbuf_reserve(m, rlen, &p)) != 0) 2572 return r; 2573 if (cipher_get_keycontext(state->receive_context, p) != (int)rlen) 2574 return SSH_ERR_INTERNAL_ERROR; 2575 if ((r = sshbuf_put_stringb(m, state->input)) != 0 || 2576 (r = sshbuf_put_stringb(m, state->output)) != 0) 2577 return r; 2578 2579 return 0; 2580 } 2581 2582 /* restore key exchange results from blob for packet state de-serialization */ 2583 static int 2584 newkeys_from_blob(struct sshbuf *m, struct ssh *ssh, int mode) 2585 { 2586 struct sshbuf *b = NULL; 2587 struct sshcomp *comp; 2588 struct sshenc *enc; 2589 struct sshmac *mac; 2590 struct newkeys *newkey = NULL; 2591 size_t keylen, ivlen, maclen; 2592 int r; 2593 2594 if ((newkey = calloc(1, sizeof(*newkey))) == NULL) { 2595 r = SSH_ERR_ALLOC_FAIL; 2596 goto out; 2597 } 2598 if ((r = sshbuf_froms(m, &b)) != 0) 2599 goto out; 2600 #ifdef DEBUG_PK 2601 sshbuf_dump(b, stderr); 2602 #endif 2603 enc = &newkey->enc; 2604 mac = &newkey->mac; 2605 comp = &newkey->comp; 2606 2607 if ((r = sshbuf_get_cstring(b, &enc->name, NULL)) != 0 || 2608 (r = sshbuf_get(b, &enc->cipher, sizeof(enc->cipher))) != 0 || 2609 (r = sshbuf_get_u32(b, (u_int *)&enc->enabled)) != 0 || 2610 (r = sshbuf_get_u32(b, &enc->block_size)) != 0 || 2611 (r = sshbuf_get_string(b, &enc->key, &keylen)) != 0 || 2612 (r = sshbuf_get_string(b, &enc->iv, &ivlen)) != 0) 2613 goto out; 2614 if (cipher_authlen(enc->cipher) == 0) { 2615 if ((r = sshbuf_get_cstring(b, &mac->name, NULL)) != 0) 2616 goto out; 2617 if ((r = mac_setup(mac, mac->name)) != 0) 2618 goto out; 2619 if ((r = sshbuf_get_u32(b, (u_int *)&mac->enabled)) != 0 || 2620 (r = sshbuf_get_string(b, &mac->key, &maclen)) != 0) 2621 goto out; 2622 if (maclen > mac->key_len) { 2623 r = SSH_ERR_INVALID_FORMAT; 2624 goto out; 2625 } 2626 mac->key_len = maclen; 2627 } 2628 if ((r = sshbuf_get_u32(b, &comp->type)) != 0 || 2629 (r = sshbuf_get_cstring(b, &comp->name, NULL)) != 0) 2630 goto out; 2631 if (enc->name == NULL || 2632 cipher_by_name(enc->name) != enc->cipher) { 2633 r = SSH_ERR_INVALID_FORMAT; 2634 goto out; 2635 } 2636 if (sshbuf_len(b) != 0) { 2637 r = SSH_ERR_INVALID_FORMAT; 2638 goto out; 2639 } 2640 enc->key_len = keylen; 2641 enc->iv_len = ivlen; 2642 ssh->kex->newkeys[mode] = newkey; 2643 newkey = NULL; 2644 r = 0; 2645 out: 2646 free(newkey); 2647 sshbuf_free(b); 2648 return r; 2649 } 2650 2651 /* restore kex from blob for packet state de-serialization */ 2652 static int 2653 kex_from_blob(struct sshbuf *m, struct kex **kexp) 2654 { 2655 struct kex *kex; 2656 int r; 2657 2658 if ((kex = calloc(1, sizeof(struct kex))) == NULL || 2659 (kex->my = sshbuf_new()) == NULL || 2660 (kex->peer = sshbuf_new()) == NULL) { 2661 r = SSH_ERR_ALLOC_FAIL; 2662 goto out; 2663 } 2664 if ((r = sshbuf_get_string(m, &kex->session_id, &kex->session_id_len)) != 0 || 2665 (r = sshbuf_get_u32(m, &kex->we_need)) != 0 || 2666 (r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_type)) != 0 || 2667 (r = sshbuf_get_u32(m, &kex->kex_type)) != 0 || 2668 (r = sshbuf_get_stringb(m, kex->my)) != 0 || 2669 (r = sshbuf_get_stringb(m, kex->peer)) != 0 || 2670 (r = sshbuf_get_u32(m, &kex->flags)) != 0 || 2671 (r = sshbuf_get_cstring(m, &kex->client_version_string, NULL)) != 0 || 2672 (r = sshbuf_get_cstring(m, &kex->server_version_string, NULL)) != 0) 2673 goto out; 2674 kex->server = 1; 2675 kex->done = 1; 2676 r = 0; 2677 out: 2678 if (r != 0 || kexp == NULL) { 2679 if (kex != NULL) { 2680 sshbuf_free(kex->my); 2681 sshbuf_free(kex->peer); 2682 free(kex); 2683 } 2684 if (kexp != NULL) 2685 *kexp = NULL; 2686 } else { 2687 *kexp = kex; 2688 } 2689 return r; 2690 } 2691 2692 /* 2693 * Restore packet state from content of blob 'm' (de-serialization). 2694 * Note that 'm' will be partially consumed on parsing or any other errors. 2695 */ 2696 int 2697 ssh_packet_set_state(struct ssh *ssh, struct sshbuf *m) 2698 { 2699 struct session_state *state = ssh->state; 2700 const u_char *ssh1key, *ivin, *ivout, *keyin, *keyout, *input, *output; 2701 size_t ssh1keylen, rlen, slen, ilen, olen; 2702 int r; 2703 u_int ssh1cipher = 0; 2704 2705 if (!compat20) { 2706 if ((r = sshbuf_get_u32(m, &state->remote_protocol_flags)) != 0 || 2707 (r = sshbuf_get_u32(m, &ssh1cipher)) != 0 || 2708 (r = sshbuf_get_string_direct(m, &ssh1key, &ssh1keylen)) != 0 || 2709 (r = sshbuf_get_string_direct(m, &ivout, &slen)) != 0 || 2710 (r = sshbuf_get_string_direct(m, &ivin, &rlen)) != 0) 2711 return r; 2712 if (ssh1cipher > INT_MAX) 2713 return SSH_ERR_KEY_UNKNOWN_CIPHER; 2714 ssh_packet_set_encryption_key(ssh, ssh1key, ssh1keylen, 2715 (int)ssh1cipher); 2716 if (cipher_get_keyiv_len(state->send_context) != (int)slen || 2717 cipher_get_keyiv_len(state->receive_context) != (int)rlen) 2718 return SSH_ERR_INVALID_FORMAT; 2719 if ((r = cipher_set_keyiv(state->send_context, ivout)) != 0 || 2720 (r = cipher_set_keyiv(state->receive_context, ivin)) != 0) 2721 return r; 2722 } else { 2723 if ((r = kex_from_blob(m, &ssh->kex)) != 0 || 2724 (r = newkeys_from_blob(m, ssh, MODE_OUT)) != 0 || 2725 (r = newkeys_from_blob(m, ssh, MODE_IN)) != 0 || 2726 (r = sshbuf_get_u64(m, &state->rekey_limit)) != 0 || 2727 (r = sshbuf_get_u32(m, &state->rekey_interval)) != 0 || 2728 (r = sshbuf_get_u32(m, &state->p_send.seqnr)) != 0 || 2729 (r = sshbuf_get_u64(m, &state->p_send.blocks)) != 0 || 2730 (r = sshbuf_get_u32(m, &state->p_send.packets)) != 0 || 2731 (r = sshbuf_get_u64(m, &state->p_send.bytes)) != 0 || 2732 (r = sshbuf_get_u32(m, &state->p_read.seqnr)) != 0 || 2733 (r = sshbuf_get_u64(m, &state->p_read.blocks)) != 0 || 2734 (r = sshbuf_get_u32(m, &state->p_read.packets)) != 0 || 2735 (r = sshbuf_get_u64(m, &state->p_read.bytes)) != 0) 2736 return r; 2737 /* 2738 * We set the time here so that in post-auth privsep slave we 2739 * count from the completion of the authentication. 2740 */ 2741 state->rekey_time = monotime(); 2742 /* XXX ssh_set_newkeys overrides p_read.packets? XXX */ 2743 if ((r = ssh_set_newkeys(ssh, MODE_IN)) != 0 || 2744 (r = ssh_set_newkeys(ssh, MODE_OUT)) != 0) 2745 return r; 2746 } 2747 if ((r = sshbuf_get_string_direct(m, &keyout, &slen)) != 0 || 2748 (r = sshbuf_get_string_direct(m, &keyin, &rlen)) != 0) 2749 return r; 2750 if (cipher_get_keycontext(state->send_context, NULL) != (int)slen || 2751 cipher_get_keycontext(state->receive_context, NULL) != (int)rlen) 2752 return SSH_ERR_INVALID_FORMAT; 2753 cipher_set_keycontext(state->send_context, keyout); 2754 cipher_set_keycontext(state->receive_context, keyin); 2755 2756 if ((r = ssh_packet_set_postauth(ssh)) != 0) 2757 return r; 2758 2759 sshbuf_reset(state->input); 2760 sshbuf_reset(state->output); 2761 if ((r = sshbuf_get_string_direct(m, &input, &ilen)) != 0 || 2762 (r = sshbuf_get_string_direct(m, &output, &olen)) != 0 || 2763 (r = sshbuf_put(state->input, input, ilen)) != 0 || 2764 (r = sshbuf_put(state->output, output, olen)) != 0) 2765 return r; 2766 2767 if (sshbuf_len(m)) 2768 return SSH_ERR_INVALID_FORMAT; 2769 debug3("%s: done", __func__); 2770 return 0; 2771 } 2772 2773 /* NEW API */ 2774 2775 /* put data to the outgoing packet */ 2776 2777 int 2778 sshpkt_put(struct ssh *ssh, const void *v, size_t len) 2779 { 2780 return sshbuf_put(ssh->state->outgoing_packet, v, len); 2781 } 2782 2783 int 2784 sshpkt_putb(struct ssh *ssh, const struct sshbuf *b) 2785 { 2786 return sshbuf_putb(ssh->state->outgoing_packet, b); 2787 } 2788 2789 int 2790 sshpkt_put_u8(struct ssh *ssh, u_char val) 2791 { 2792 return sshbuf_put_u8(ssh->state->outgoing_packet, val); 2793 } 2794 2795 int 2796 sshpkt_put_u32(struct ssh *ssh, u_int32_t val) 2797 { 2798 return sshbuf_put_u32(ssh->state->outgoing_packet, val); 2799 } 2800 2801 int 2802 sshpkt_put_u64(struct ssh *ssh, u_int64_t val) 2803 { 2804 return sshbuf_put_u64(ssh->state->outgoing_packet, val); 2805 } 2806 2807 int 2808 sshpkt_put_string(struct ssh *ssh, const void *v, size_t len) 2809 { 2810 return sshbuf_put_string(ssh->state->outgoing_packet, v, len); 2811 } 2812 2813 int 2814 sshpkt_put_cstring(struct ssh *ssh, const void *v) 2815 { 2816 return sshbuf_put_cstring(ssh->state->outgoing_packet, v); 2817 } 2818 2819 int 2820 sshpkt_put_stringb(struct ssh *ssh, const struct sshbuf *v) 2821 { 2822 return sshbuf_put_stringb(ssh->state->outgoing_packet, v); 2823 } 2824 2825 #ifdef WITH_OPENSSL 2826 int 2827 sshpkt_put_ec(struct ssh *ssh, const EC_POINT *v, const EC_GROUP *g) 2828 { 2829 return sshbuf_put_ec(ssh->state->outgoing_packet, v, g); 2830 } 2831 2832 #ifdef WITH_SSH1 2833 int 2834 sshpkt_put_bignum1(struct ssh *ssh, const BIGNUM *v) 2835 { 2836 return sshbuf_put_bignum1(ssh->state->outgoing_packet, v); 2837 } 2838 #endif /* WITH_SSH1 */ 2839 2840 int 2841 sshpkt_put_bignum2(struct ssh *ssh, const BIGNUM *v) 2842 { 2843 return sshbuf_put_bignum2(ssh->state->outgoing_packet, v); 2844 } 2845 #endif /* WITH_OPENSSL */ 2846 2847 /* fetch data from the incoming packet */ 2848 2849 int 2850 sshpkt_get(struct ssh *ssh, void *valp, size_t len) 2851 { 2852 return sshbuf_get(ssh->state->incoming_packet, valp, len); 2853 } 2854 2855 int 2856 sshpkt_get_u8(struct ssh *ssh, u_char *valp) 2857 { 2858 return sshbuf_get_u8(ssh->state->incoming_packet, valp); 2859 } 2860 2861 int 2862 sshpkt_get_u32(struct ssh *ssh, u_int32_t *valp) 2863 { 2864 return sshbuf_get_u32(ssh->state->incoming_packet, valp); 2865 } 2866 2867 int 2868 sshpkt_get_u64(struct ssh *ssh, u_int64_t *valp) 2869 { 2870 return sshbuf_get_u64(ssh->state->incoming_packet, valp); 2871 } 2872 2873 int 2874 sshpkt_get_string(struct ssh *ssh, u_char **valp, size_t *lenp) 2875 { 2876 return sshbuf_get_string(ssh->state->incoming_packet, valp, lenp); 2877 } 2878 2879 int 2880 sshpkt_get_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp) 2881 { 2882 return sshbuf_get_string_direct(ssh->state->incoming_packet, valp, lenp); 2883 } 2884 2885 int 2886 sshpkt_get_cstring(struct ssh *ssh, char **valp, size_t *lenp) 2887 { 2888 return sshbuf_get_cstring(ssh->state->incoming_packet, valp, lenp); 2889 } 2890 2891 #ifdef WITH_OPENSSL 2892 int 2893 sshpkt_get_ec(struct ssh *ssh, EC_POINT *v, const EC_GROUP *g) 2894 { 2895 return sshbuf_get_ec(ssh->state->incoming_packet, v, g); 2896 } 2897 2898 #ifdef WITH_SSH1 2899 int 2900 sshpkt_get_bignum1(struct ssh *ssh, BIGNUM *v) 2901 { 2902 return sshbuf_get_bignum1(ssh->state->incoming_packet, v); 2903 } 2904 #endif /* WITH_SSH1 */ 2905 2906 int 2907 sshpkt_get_bignum2(struct ssh *ssh, BIGNUM *v) 2908 { 2909 return sshbuf_get_bignum2(ssh->state->incoming_packet, v); 2910 } 2911 #endif /* WITH_OPENSSL */ 2912 2913 int 2914 sshpkt_get_end(struct ssh *ssh) 2915 { 2916 if (sshbuf_len(ssh->state->incoming_packet) > 0) 2917 return SSH_ERR_UNEXPECTED_TRAILING_DATA; 2918 return 0; 2919 } 2920 2921 const u_char * 2922 sshpkt_ptr(struct ssh *ssh, size_t *lenp) 2923 { 2924 if (lenp != NULL) 2925 *lenp = sshbuf_len(ssh->state->incoming_packet); 2926 return sshbuf_ptr(ssh->state->incoming_packet); 2927 } 2928 2929 /* start a new packet */ 2930 2931 int 2932 sshpkt_start(struct ssh *ssh, u_char type) 2933 { 2934 u_char buf[9]; 2935 int len; 2936 2937 DBG(debug("packet_start[%d]", type)); 2938 len = compat20 ? 6 : 9; 2939 memset(buf, 0, len - 1); 2940 buf[len - 1] = type; 2941 sshbuf_reset(ssh->state->outgoing_packet); 2942 return sshbuf_put(ssh->state->outgoing_packet, buf, len); 2943 } 2944 2945 static int 2946 ssh_packet_send_mux(struct ssh *ssh) 2947 { 2948 struct session_state *state = ssh->state; 2949 u_char type, *cp; 2950 size_t len; 2951 int r; 2952 2953 if (ssh->kex) 2954 return SSH_ERR_INTERNAL_ERROR; 2955 len = sshbuf_len(state->outgoing_packet); 2956 if (len < 6) 2957 return SSH_ERR_INTERNAL_ERROR; 2958 cp = sshbuf_mutable_ptr(state->outgoing_packet); 2959 type = cp[5]; 2960 if (ssh_packet_log_type(type)) 2961 debug3("%s: type %u", __func__, type); 2962 /* drop everything, but the connection protocol */ 2963 if (type >= SSH2_MSG_CONNECTION_MIN && 2964 type <= SSH2_MSG_CONNECTION_MAX) { 2965 POKE_U32(cp, len - 4); 2966 if ((r = sshbuf_putb(state->output, 2967 state->outgoing_packet)) != 0) 2968 return r; 2969 /* sshbuf_dump(state->output, stderr); */ 2970 } 2971 sshbuf_reset(state->outgoing_packet); 2972 return 0; 2973 } 2974 2975 /* send it */ 2976 2977 int 2978 sshpkt_sendx(struct ssh *ssh) 2979 { 2980 if (ssh->state && ssh->state->mux) 2981 return ssh_packet_send_mux(ssh); 2982 if (compat20) 2983 return ssh_packet_send2(ssh); 2984 else 2985 return ssh_packet_send1(ssh); 2986 } 2987 2988 int 2989 sshpkt_send(struct ssh *ssh) 2990 { 2991 int r = sshpkt_sendx(ssh); 2992 return r < 0 ? r : 0; 2993 } 2994 2995 int 2996 sshpkt_disconnect(struct ssh *ssh, const char *fmt,...) 2997 { 2998 char buf[1024]; 2999 va_list args; 3000 int r; 3001 3002 va_start(args, fmt); 3003 vsnprintf(buf, sizeof(buf), fmt, args); 3004 va_end(args); 3005 3006 if (compat20) { 3007 if ((r = sshpkt_start(ssh, SSH2_MSG_DISCONNECT)) != 0 || 3008 (r = sshpkt_put_u32(ssh, SSH2_DISCONNECT_PROTOCOL_ERROR)) != 0 || 3009 (r = sshpkt_put_cstring(ssh, buf)) != 0 || 3010 (r = sshpkt_put_cstring(ssh, "")) != 0 || 3011 (r = sshpkt_send(ssh)) != 0) 3012 return r; 3013 } else { 3014 if ((r = sshpkt_start(ssh, SSH_MSG_DISCONNECT)) != 0 || 3015 (r = sshpkt_put_cstring(ssh, buf)) != 0 || 3016 (r = sshpkt_send(ssh)) != 0) 3017 return r; 3018 } 3019 return 0; 3020 } 3021 3022 /* roundup current message to pad bytes */ 3023 int 3024 sshpkt_add_padding(struct ssh *ssh, u_char pad) 3025 { 3026 ssh->state->extra_pad = pad; 3027 return 0; 3028 } 3029 3030 int 3031 ssh_packet_authentication_state(void) 3032 { 3033 return active_state->state->after_authentication; 3034 } 3035