1 /* $OpenBSD: packet.c,v 1.301 2021/07/16 09:00:23 djm Exp $ */ 2 /* 3 * Author: Tatu Ylonen <ylo@cs.hut.fi> 4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 5 * All rights reserved 6 * This file contains code implementing the packet protocol and communication 7 * with the other side. This same code is used both on client and server side. 8 * 9 * As far as I am concerned, the code I have written for this software 10 * can be used freely for any purpose. Any derived versions of this 11 * software must be clearly marked as such, and if the derived work is 12 * incompatible with the protocol description in the RFC file, it must be 13 * called by a name other than "ssh" or "Secure Shell". 14 * 15 * 16 * SSH2 packet format added by Markus Friedl. 17 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. 18 * 19 * Redistribution and use in source and binary forms, with or without 20 * modification, are permitted provided that the following conditions 21 * are met: 22 * 1. Redistributions of source code must retain the above copyright 23 * notice, this list of conditions and the following disclaimer. 24 * 2. Redistributions in binary form must reproduce the above copyright 25 * notice, this list of conditions and the following disclaimer in the 26 * documentation and/or other materials provided with the distribution. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 29 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 30 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 31 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 32 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 33 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 34 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 35 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 36 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 37 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 38 */ 39 40 #include "includes.h" 41 __RCSID("$FreeBSD$"); 42 43 #include <sys/types.h> 44 #include "openbsd-compat/sys-queue.h" 45 #include <sys/socket.h> 46 #ifdef HAVE_SYS_TIME_H 47 # include <sys/time.h> 48 #endif 49 50 #include <netinet/in.h> 51 #include <netinet/ip.h> 52 #include <arpa/inet.h> 53 54 #include <errno.h> 55 #include <netdb.h> 56 #include <stdarg.h> 57 #include <stdio.h> 58 #include <stdlib.h> 59 #include <string.h> 60 #include <unistd.h> 61 #include <limits.h> 62 #ifdef HAVE_POLL_H 63 #include <poll.h> 64 #endif 65 #include <signal.h> 66 #include <time.h> 67 68 /* 69 * Explicitly include OpenSSL before zlib as some versions of OpenSSL have 70 * "free_func" in their headers, which zlib typedefs. 71 */ 72 #ifdef WITH_OPENSSL 73 # include <openssl/bn.h> 74 # include <openssl/evp.h> 75 # ifdef OPENSSL_HAS_ECC 76 # include <openssl/ec.h> 77 # endif 78 #endif 79 80 #ifdef WITH_ZLIB 81 #include <zlib.h> 82 #endif 83 84 #include "xmalloc.h" 85 #include "compat.h" 86 #include "ssh2.h" 87 #include "cipher.h" 88 #include "sshkey.h" 89 #include "kex.h" 90 #include "digest.h" 91 #include "mac.h" 92 #include "log.h" 93 #include "canohost.h" 94 #include "misc.h" 95 #include "channels.h" 96 #include "ssh.h" 97 #include "packet.h" 98 #include "ssherr.h" 99 #include "sshbuf.h" 100 #include "blacklist_client.h" 101 102 #ifdef PACKET_DEBUG 103 #define DBG(x) x 104 #else 105 #define DBG(x) 106 #endif 107 108 #define PACKET_MAX_SIZE (256 * 1024) 109 110 struct packet_state { 111 u_int32_t seqnr; 112 u_int32_t packets; 113 u_int64_t blocks; 114 u_int64_t bytes; 115 }; 116 117 struct packet { 118 TAILQ_ENTRY(packet) next; 119 u_char type; 120 struct sshbuf *payload; 121 }; 122 123 struct session_state { 124 /* 125 * This variable contains the file descriptors used for 126 * communicating with the other side. connection_in is used for 127 * reading; connection_out for writing. These can be the same 128 * descriptor, in which case it is assumed to be a socket. 129 */ 130 int connection_in; 131 int connection_out; 132 133 /* Protocol flags for the remote side. */ 134 u_int remote_protocol_flags; 135 136 /* Encryption context for receiving data. Only used for decryption. */ 137 struct sshcipher_ctx *receive_context; 138 139 /* Encryption context for sending data. Only used for encryption. */ 140 struct sshcipher_ctx *send_context; 141 142 /* Buffer for raw input data from the socket. */ 143 struct sshbuf *input; 144 145 /* Buffer for raw output data going to the socket. */ 146 struct sshbuf *output; 147 148 /* Buffer for the partial outgoing packet being constructed. */ 149 struct sshbuf *outgoing_packet; 150 151 /* Buffer for the incoming packet currently being processed. */ 152 struct sshbuf *incoming_packet; 153 154 /* Scratch buffer for packet compression/decompression. */ 155 struct sshbuf *compression_buffer; 156 157 #ifdef WITH_ZLIB 158 /* Incoming/outgoing compression dictionaries */ 159 z_stream compression_in_stream; 160 z_stream compression_out_stream; 161 #endif 162 int compression_in_started; 163 int compression_out_started; 164 int compression_in_failures; 165 int compression_out_failures; 166 167 /* default maximum packet size */ 168 u_int max_packet_size; 169 170 /* Flag indicating whether this module has been initialized. */ 171 int initialized; 172 173 /* Set to true if the connection is interactive. */ 174 int interactive_mode; 175 176 /* Set to true if we are the server side. */ 177 int server_side; 178 179 /* Set to true if we are authenticated. */ 180 int after_authentication; 181 182 int keep_alive_timeouts; 183 184 /* The maximum time that we will wait to send or receive a packet */ 185 int packet_timeout_ms; 186 187 /* Session key information for Encryption and MAC */ 188 struct newkeys *newkeys[MODE_MAX]; 189 struct packet_state p_read, p_send; 190 191 /* Volume-based rekeying */ 192 u_int64_t max_blocks_in, max_blocks_out, rekey_limit; 193 194 /* Time-based rekeying */ 195 u_int32_t rekey_interval; /* how often in seconds */ 196 time_t rekey_time; /* time of last rekeying */ 197 198 /* roundup current message to extra_pad bytes */ 199 u_char extra_pad; 200 201 /* XXX discard incoming data after MAC error */ 202 u_int packet_discard; 203 size_t packet_discard_mac_already; 204 struct sshmac *packet_discard_mac; 205 206 /* Used in packet_read_poll2() */ 207 u_int packlen; 208 209 /* Used in packet_send2 */ 210 int rekeying; 211 212 /* Used in ssh_packet_send_mux() */ 213 int mux; 214 215 /* Used in packet_set_interactive */ 216 int set_interactive_called; 217 218 /* Used in packet_set_maxsize */ 219 int set_maxsize_called; 220 221 /* One-off warning about weak ciphers */ 222 int cipher_warning_done; 223 224 /* Hook for fuzzing inbound packets */ 225 ssh_packet_hook_fn *hook_in; 226 void *hook_in_ctx; 227 228 TAILQ_HEAD(, packet) outgoing; 229 }; 230 231 struct ssh * 232 ssh_alloc_session_state(void) 233 { 234 struct ssh *ssh = NULL; 235 struct session_state *state = NULL; 236 237 if ((ssh = calloc(1, sizeof(*ssh))) == NULL || 238 (state = calloc(1, sizeof(*state))) == NULL || 239 (ssh->kex = kex_new()) == NULL || 240 (state->input = sshbuf_new()) == NULL || 241 (state->output = sshbuf_new()) == NULL || 242 (state->outgoing_packet = sshbuf_new()) == NULL || 243 (state->incoming_packet = sshbuf_new()) == NULL) 244 goto fail; 245 TAILQ_INIT(&state->outgoing); 246 TAILQ_INIT(&ssh->private_keys); 247 TAILQ_INIT(&ssh->public_keys); 248 state->connection_in = -1; 249 state->connection_out = -1; 250 state->max_packet_size = 32768; 251 state->packet_timeout_ms = -1; 252 state->p_send.packets = state->p_read.packets = 0; 253 state->initialized = 1; 254 /* 255 * ssh_packet_send2() needs to queue packets until 256 * we've done the initial key exchange. 257 */ 258 state->rekeying = 1; 259 ssh->state = state; 260 return ssh; 261 fail: 262 if (ssh) { 263 kex_free(ssh->kex); 264 free(ssh); 265 } 266 if (state) { 267 sshbuf_free(state->input); 268 sshbuf_free(state->output); 269 sshbuf_free(state->incoming_packet); 270 sshbuf_free(state->outgoing_packet); 271 free(state); 272 } 273 return NULL; 274 } 275 276 void 277 ssh_packet_set_input_hook(struct ssh *ssh, ssh_packet_hook_fn *hook, void *ctx) 278 { 279 ssh->state->hook_in = hook; 280 ssh->state->hook_in_ctx = ctx; 281 } 282 283 /* Returns nonzero if rekeying is in progress */ 284 int 285 ssh_packet_is_rekeying(struct ssh *ssh) 286 { 287 return ssh->state->rekeying || 288 (ssh->kex != NULL && ssh->kex->done == 0); 289 } 290 291 /* 292 * Sets the descriptors used for communication. 293 */ 294 struct ssh * 295 ssh_packet_set_connection(struct ssh *ssh, int fd_in, int fd_out) 296 { 297 struct session_state *state; 298 const struct sshcipher *none = cipher_by_name("none"); 299 int r; 300 301 if (none == NULL) { 302 error_f("cannot load cipher 'none'"); 303 return NULL; 304 } 305 if (ssh == NULL) 306 ssh = ssh_alloc_session_state(); 307 if (ssh == NULL) { 308 error_f("could not allocate state"); 309 return NULL; 310 } 311 state = ssh->state; 312 state->connection_in = fd_in; 313 state->connection_out = fd_out; 314 if ((r = cipher_init(&state->send_context, none, 315 (const u_char *)"", 0, NULL, 0, CIPHER_ENCRYPT)) != 0 || 316 (r = cipher_init(&state->receive_context, none, 317 (const u_char *)"", 0, NULL, 0, CIPHER_DECRYPT)) != 0) { 318 error_fr(r, "cipher_init failed"); 319 free(ssh); /* XXX need ssh_free_session_state? */ 320 return NULL; 321 } 322 state->newkeys[MODE_IN] = state->newkeys[MODE_OUT] = NULL; 323 /* 324 * Cache the IP address of the remote connection for use in error 325 * messages that might be generated after the connection has closed. 326 */ 327 (void)ssh_remote_ipaddr(ssh); 328 return ssh; 329 } 330 331 void 332 ssh_packet_set_timeout(struct ssh *ssh, int timeout, int count) 333 { 334 struct session_state *state = ssh->state; 335 336 if (timeout <= 0 || count <= 0) { 337 state->packet_timeout_ms = -1; 338 return; 339 } 340 if ((INT_MAX / 1000) / count < timeout) 341 state->packet_timeout_ms = INT_MAX; 342 else 343 state->packet_timeout_ms = timeout * count * 1000; 344 } 345 346 void 347 ssh_packet_set_mux(struct ssh *ssh) 348 { 349 ssh->state->mux = 1; 350 ssh->state->rekeying = 0; 351 kex_free(ssh->kex); 352 ssh->kex = NULL; 353 } 354 355 int 356 ssh_packet_get_mux(struct ssh *ssh) 357 { 358 return ssh->state->mux; 359 } 360 361 int 362 ssh_packet_set_log_preamble(struct ssh *ssh, const char *fmt, ...) 363 { 364 va_list args; 365 int r; 366 367 free(ssh->log_preamble); 368 if (fmt == NULL) 369 ssh->log_preamble = NULL; 370 else { 371 va_start(args, fmt); 372 r = vasprintf(&ssh->log_preamble, fmt, args); 373 va_end(args); 374 if (r < 0 || ssh->log_preamble == NULL) 375 return SSH_ERR_ALLOC_FAIL; 376 } 377 return 0; 378 } 379 380 int 381 ssh_packet_stop_discard(struct ssh *ssh) 382 { 383 struct session_state *state = ssh->state; 384 int r; 385 386 if (state->packet_discard_mac) { 387 char buf[1024]; 388 size_t dlen = PACKET_MAX_SIZE; 389 390 if (dlen > state->packet_discard_mac_already) 391 dlen -= state->packet_discard_mac_already; 392 memset(buf, 'a', sizeof(buf)); 393 while (sshbuf_len(state->incoming_packet) < dlen) 394 if ((r = sshbuf_put(state->incoming_packet, buf, 395 sizeof(buf))) != 0) 396 return r; 397 (void) mac_compute(state->packet_discard_mac, 398 state->p_read.seqnr, 399 sshbuf_ptr(state->incoming_packet), dlen, 400 NULL, 0); 401 } 402 logit("Finished discarding for %.200s port %d", 403 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 404 return SSH_ERR_MAC_INVALID; 405 } 406 407 static int 408 ssh_packet_start_discard(struct ssh *ssh, struct sshenc *enc, 409 struct sshmac *mac, size_t mac_already, u_int discard) 410 { 411 struct session_state *state = ssh->state; 412 int r; 413 414 if (enc == NULL || !cipher_is_cbc(enc->cipher) || (mac && mac->etm)) { 415 if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0) 416 return r; 417 return SSH_ERR_MAC_INVALID; 418 } 419 /* 420 * Record number of bytes over which the mac has already 421 * been computed in order to minimize timing attacks. 422 */ 423 if (mac && mac->enabled) { 424 state->packet_discard_mac = mac; 425 state->packet_discard_mac_already = mac_already; 426 } 427 if (sshbuf_len(state->input) >= discard) 428 return ssh_packet_stop_discard(ssh); 429 state->packet_discard = discard - sshbuf_len(state->input); 430 return 0; 431 } 432 433 /* Returns 1 if remote host is connected via socket, 0 if not. */ 434 435 int 436 ssh_packet_connection_is_on_socket(struct ssh *ssh) 437 { 438 struct session_state *state; 439 struct sockaddr_storage from, to; 440 socklen_t fromlen, tolen; 441 442 if (ssh == NULL || ssh->state == NULL) 443 return 0; 444 445 state = ssh->state; 446 if (state->connection_in == -1 || state->connection_out == -1) 447 return 0; 448 /* filedescriptors in and out are the same, so it's a socket */ 449 if (state->connection_in == state->connection_out) 450 return 1; 451 fromlen = sizeof(from); 452 memset(&from, 0, sizeof(from)); 453 if (getpeername(state->connection_in, (struct sockaddr *)&from, 454 &fromlen) == -1) 455 return 0; 456 tolen = sizeof(to); 457 memset(&to, 0, sizeof(to)); 458 if (getpeername(state->connection_out, (struct sockaddr *)&to, 459 &tolen) == -1) 460 return 0; 461 if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0) 462 return 0; 463 if (from.ss_family != AF_INET && from.ss_family != AF_INET6) 464 return 0; 465 return 1; 466 } 467 468 void 469 ssh_packet_get_bytes(struct ssh *ssh, u_int64_t *ibytes, u_int64_t *obytes) 470 { 471 if (ibytes) 472 *ibytes = ssh->state->p_read.bytes; 473 if (obytes) 474 *obytes = ssh->state->p_send.bytes; 475 } 476 477 int 478 ssh_packet_connection_af(struct ssh *ssh) 479 { 480 return get_sock_af(ssh->state->connection_out); 481 } 482 483 /* Sets the connection into non-blocking mode. */ 484 485 void 486 ssh_packet_set_nonblocking(struct ssh *ssh) 487 { 488 /* Set the socket into non-blocking mode. */ 489 set_nonblock(ssh->state->connection_in); 490 491 if (ssh->state->connection_out != ssh->state->connection_in) 492 set_nonblock(ssh->state->connection_out); 493 } 494 495 /* Returns the socket used for reading. */ 496 497 int 498 ssh_packet_get_connection_in(struct ssh *ssh) 499 { 500 return ssh->state->connection_in; 501 } 502 503 /* Returns the descriptor used for writing. */ 504 505 int 506 ssh_packet_get_connection_out(struct ssh *ssh) 507 { 508 return ssh->state->connection_out; 509 } 510 511 /* 512 * Returns the IP-address of the remote host as a string. The returned 513 * string must not be freed. 514 */ 515 516 const char * 517 ssh_remote_ipaddr(struct ssh *ssh) 518 { 519 int sock; 520 521 /* Check whether we have cached the ipaddr. */ 522 if (ssh->remote_ipaddr == NULL) { 523 if (ssh_packet_connection_is_on_socket(ssh)) { 524 sock = ssh->state->connection_in; 525 ssh->remote_ipaddr = get_peer_ipaddr(sock); 526 ssh->remote_port = get_peer_port(sock); 527 ssh->local_ipaddr = get_local_ipaddr(sock); 528 ssh->local_port = get_local_port(sock); 529 } else { 530 ssh->remote_ipaddr = xstrdup("UNKNOWN"); 531 ssh->remote_port = 65535; 532 ssh->local_ipaddr = xstrdup("UNKNOWN"); 533 ssh->local_port = 65535; 534 } 535 } 536 return ssh->remote_ipaddr; 537 } 538 539 /* Returns the port number of the remote host. */ 540 541 int 542 ssh_remote_port(struct ssh *ssh) 543 { 544 (void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */ 545 return ssh->remote_port; 546 } 547 548 /* 549 * Returns the IP-address of the local host as a string. The returned 550 * string must not be freed. 551 */ 552 553 const char * 554 ssh_local_ipaddr(struct ssh *ssh) 555 { 556 (void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */ 557 return ssh->local_ipaddr; 558 } 559 560 /* Returns the port number of the local host. */ 561 562 int 563 ssh_local_port(struct ssh *ssh) 564 { 565 (void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */ 566 return ssh->local_port; 567 } 568 569 /* Returns the routing domain of the input socket, or NULL if unavailable */ 570 const char * 571 ssh_packet_rdomain_in(struct ssh *ssh) 572 { 573 if (ssh->rdomain_in != NULL) 574 return ssh->rdomain_in; 575 if (!ssh_packet_connection_is_on_socket(ssh)) 576 return NULL; 577 ssh->rdomain_in = get_rdomain(ssh->state->connection_in); 578 return ssh->rdomain_in; 579 } 580 581 /* Closes the connection and clears and frees internal data structures. */ 582 583 static void 584 ssh_packet_close_internal(struct ssh *ssh, int do_close) 585 { 586 struct session_state *state = ssh->state; 587 u_int mode; 588 589 if (!state->initialized) 590 return; 591 state->initialized = 0; 592 if (do_close) { 593 if (state->connection_in == state->connection_out) { 594 close(state->connection_out); 595 } else { 596 close(state->connection_in); 597 close(state->connection_out); 598 } 599 } 600 sshbuf_free(state->input); 601 sshbuf_free(state->output); 602 sshbuf_free(state->outgoing_packet); 603 sshbuf_free(state->incoming_packet); 604 for (mode = 0; mode < MODE_MAX; mode++) { 605 kex_free_newkeys(state->newkeys[mode]); /* current keys */ 606 state->newkeys[mode] = NULL; 607 ssh_clear_newkeys(ssh, mode); /* next keys */ 608 } 609 #ifdef WITH_ZLIB 610 /* compression state is in shared mem, so we can only release it once */ 611 if (do_close && state->compression_buffer) { 612 sshbuf_free(state->compression_buffer); 613 if (state->compression_out_started) { 614 z_streamp stream = &state->compression_out_stream; 615 debug("compress outgoing: " 616 "raw data %llu, compressed %llu, factor %.2f", 617 (unsigned long long)stream->total_in, 618 (unsigned long long)stream->total_out, 619 stream->total_in == 0 ? 0.0 : 620 (double) stream->total_out / stream->total_in); 621 if (state->compression_out_failures == 0) 622 deflateEnd(stream); 623 } 624 if (state->compression_in_started) { 625 z_streamp stream = &state->compression_in_stream; 626 debug("compress incoming: " 627 "raw data %llu, compressed %llu, factor %.2f", 628 (unsigned long long)stream->total_out, 629 (unsigned long long)stream->total_in, 630 stream->total_out == 0 ? 0.0 : 631 (double) stream->total_in / stream->total_out); 632 if (state->compression_in_failures == 0) 633 inflateEnd(stream); 634 } 635 } 636 #endif /* WITH_ZLIB */ 637 cipher_free(state->send_context); 638 cipher_free(state->receive_context); 639 state->send_context = state->receive_context = NULL; 640 if (do_close) { 641 free(ssh->local_ipaddr); 642 ssh->local_ipaddr = NULL; 643 free(ssh->remote_ipaddr); 644 ssh->remote_ipaddr = NULL; 645 free(ssh->state); 646 ssh->state = NULL; 647 kex_free(ssh->kex); 648 ssh->kex = NULL; 649 } 650 } 651 652 void 653 ssh_packet_close(struct ssh *ssh) 654 { 655 ssh_packet_close_internal(ssh, 1); 656 } 657 658 void 659 ssh_packet_clear_keys(struct ssh *ssh) 660 { 661 ssh_packet_close_internal(ssh, 0); 662 } 663 664 /* Sets remote side protocol flags. */ 665 666 void 667 ssh_packet_set_protocol_flags(struct ssh *ssh, u_int protocol_flags) 668 { 669 ssh->state->remote_protocol_flags = protocol_flags; 670 } 671 672 /* Returns the remote protocol flags set earlier by the above function. */ 673 674 u_int 675 ssh_packet_get_protocol_flags(struct ssh *ssh) 676 { 677 return ssh->state->remote_protocol_flags; 678 } 679 680 /* 681 * Starts packet compression from the next packet on in both directions. 682 * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip. 683 */ 684 685 static int 686 ssh_packet_init_compression(struct ssh *ssh) 687 { 688 if (!ssh->state->compression_buffer && 689 ((ssh->state->compression_buffer = sshbuf_new()) == NULL)) 690 return SSH_ERR_ALLOC_FAIL; 691 return 0; 692 } 693 694 #ifdef WITH_ZLIB 695 static int 696 start_compression_out(struct ssh *ssh, int level) 697 { 698 if (level < 1 || level > 9) 699 return SSH_ERR_INVALID_ARGUMENT; 700 debug("Enabling compression at level %d.", level); 701 if (ssh->state->compression_out_started == 1) 702 deflateEnd(&ssh->state->compression_out_stream); 703 switch (deflateInit(&ssh->state->compression_out_stream, level)) { 704 case Z_OK: 705 ssh->state->compression_out_started = 1; 706 break; 707 case Z_MEM_ERROR: 708 return SSH_ERR_ALLOC_FAIL; 709 default: 710 return SSH_ERR_INTERNAL_ERROR; 711 } 712 return 0; 713 } 714 715 static int 716 start_compression_in(struct ssh *ssh) 717 { 718 if (ssh->state->compression_in_started == 1) 719 inflateEnd(&ssh->state->compression_in_stream); 720 switch (inflateInit(&ssh->state->compression_in_stream)) { 721 case Z_OK: 722 ssh->state->compression_in_started = 1; 723 break; 724 case Z_MEM_ERROR: 725 return SSH_ERR_ALLOC_FAIL; 726 default: 727 return SSH_ERR_INTERNAL_ERROR; 728 } 729 return 0; 730 } 731 732 /* XXX remove need for separate compression buffer */ 733 static int 734 compress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out) 735 { 736 u_char buf[4096]; 737 int r, status; 738 739 if (ssh->state->compression_out_started != 1) 740 return SSH_ERR_INTERNAL_ERROR; 741 742 /* This case is not handled below. */ 743 if (sshbuf_len(in) == 0) 744 return 0; 745 746 /* Input is the contents of the input buffer. */ 747 if ((ssh->state->compression_out_stream.next_in = 748 sshbuf_mutable_ptr(in)) == NULL) 749 return SSH_ERR_INTERNAL_ERROR; 750 ssh->state->compression_out_stream.avail_in = sshbuf_len(in); 751 752 /* Loop compressing until deflate() returns with avail_out != 0. */ 753 do { 754 /* Set up fixed-size output buffer. */ 755 ssh->state->compression_out_stream.next_out = buf; 756 ssh->state->compression_out_stream.avail_out = sizeof(buf); 757 758 /* Compress as much data into the buffer as possible. */ 759 status = deflate(&ssh->state->compression_out_stream, 760 Z_PARTIAL_FLUSH); 761 switch (status) { 762 case Z_MEM_ERROR: 763 return SSH_ERR_ALLOC_FAIL; 764 case Z_OK: 765 /* Append compressed data to output_buffer. */ 766 if ((r = sshbuf_put(out, buf, sizeof(buf) - 767 ssh->state->compression_out_stream.avail_out)) != 0) 768 return r; 769 break; 770 case Z_STREAM_ERROR: 771 default: 772 ssh->state->compression_out_failures++; 773 return SSH_ERR_INVALID_FORMAT; 774 } 775 } while (ssh->state->compression_out_stream.avail_out == 0); 776 return 0; 777 } 778 779 static int 780 uncompress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out) 781 { 782 u_char buf[4096]; 783 int r, status; 784 785 if (ssh->state->compression_in_started != 1) 786 return SSH_ERR_INTERNAL_ERROR; 787 788 if ((ssh->state->compression_in_stream.next_in = 789 sshbuf_mutable_ptr(in)) == NULL) 790 return SSH_ERR_INTERNAL_ERROR; 791 ssh->state->compression_in_stream.avail_in = sshbuf_len(in); 792 793 for (;;) { 794 /* Set up fixed-size output buffer. */ 795 ssh->state->compression_in_stream.next_out = buf; 796 ssh->state->compression_in_stream.avail_out = sizeof(buf); 797 798 status = inflate(&ssh->state->compression_in_stream, 799 Z_PARTIAL_FLUSH); 800 switch (status) { 801 case Z_OK: 802 if ((r = sshbuf_put(out, buf, sizeof(buf) - 803 ssh->state->compression_in_stream.avail_out)) != 0) 804 return r; 805 break; 806 case Z_BUF_ERROR: 807 /* 808 * Comments in zlib.h say that we should keep calling 809 * inflate() until we get an error. This appears to 810 * be the error that we get. 811 */ 812 return 0; 813 case Z_DATA_ERROR: 814 return SSH_ERR_INVALID_FORMAT; 815 case Z_MEM_ERROR: 816 return SSH_ERR_ALLOC_FAIL; 817 case Z_STREAM_ERROR: 818 default: 819 ssh->state->compression_in_failures++; 820 return SSH_ERR_INTERNAL_ERROR; 821 } 822 } 823 /* NOTREACHED */ 824 } 825 826 #else /* WITH_ZLIB */ 827 828 static int 829 start_compression_out(struct ssh *ssh, int level) 830 { 831 return SSH_ERR_INTERNAL_ERROR; 832 } 833 834 static int 835 start_compression_in(struct ssh *ssh) 836 { 837 return SSH_ERR_INTERNAL_ERROR; 838 } 839 840 static int 841 compress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out) 842 { 843 return SSH_ERR_INTERNAL_ERROR; 844 } 845 846 static int 847 uncompress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out) 848 { 849 return SSH_ERR_INTERNAL_ERROR; 850 } 851 #endif /* WITH_ZLIB */ 852 853 void 854 ssh_clear_newkeys(struct ssh *ssh, int mode) 855 { 856 if (ssh->kex && ssh->kex->newkeys[mode]) { 857 kex_free_newkeys(ssh->kex->newkeys[mode]); 858 ssh->kex->newkeys[mode] = NULL; 859 } 860 } 861 862 int 863 ssh_set_newkeys(struct ssh *ssh, int mode) 864 { 865 struct session_state *state = ssh->state; 866 struct sshenc *enc; 867 struct sshmac *mac; 868 struct sshcomp *comp; 869 struct sshcipher_ctx **ccp; 870 struct packet_state *ps; 871 u_int64_t *max_blocks; 872 const char *wmsg; 873 int r, crypt_type; 874 const char *dir = mode == MODE_OUT ? "out" : "in"; 875 876 debug2("set_newkeys: mode %d", mode); 877 878 if (mode == MODE_OUT) { 879 ccp = &state->send_context; 880 crypt_type = CIPHER_ENCRYPT; 881 ps = &state->p_send; 882 max_blocks = &state->max_blocks_out; 883 } else { 884 ccp = &state->receive_context; 885 crypt_type = CIPHER_DECRYPT; 886 ps = &state->p_read; 887 max_blocks = &state->max_blocks_in; 888 } 889 if (state->newkeys[mode] != NULL) { 890 debug_f("rekeying %s, input %llu bytes %llu blocks, " 891 "output %llu bytes %llu blocks", dir, 892 (unsigned long long)state->p_read.bytes, 893 (unsigned long long)state->p_read.blocks, 894 (unsigned long long)state->p_send.bytes, 895 (unsigned long long)state->p_send.blocks); 896 kex_free_newkeys(state->newkeys[mode]); 897 state->newkeys[mode] = NULL; 898 } 899 /* note that both bytes and the seqnr are not reset */ 900 ps->packets = ps->blocks = 0; 901 /* move newkeys from kex to state */ 902 if ((state->newkeys[mode] = ssh->kex->newkeys[mode]) == NULL) 903 return SSH_ERR_INTERNAL_ERROR; 904 ssh->kex->newkeys[mode] = NULL; 905 enc = &state->newkeys[mode]->enc; 906 mac = &state->newkeys[mode]->mac; 907 comp = &state->newkeys[mode]->comp; 908 if (cipher_authlen(enc->cipher) == 0) { 909 if ((r = mac_init(mac)) != 0) 910 return r; 911 } 912 mac->enabled = 1; 913 DBG(debug_f("cipher_init_context: %s", dir)); 914 cipher_free(*ccp); 915 *ccp = NULL; 916 if ((r = cipher_init(ccp, enc->cipher, enc->key, enc->key_len, 917 enc->iv, enc->iv_len, crypt_type)) != 0) 918 return r; 919 if (!state->cipher_warning_done && 920 (wmsg = cipher_warning_message(*ccp)) != NULL) { 921 error("Warning: %s", wmsg); 922 state->cipher_warning_done = 1; 923 } 924 /* Deleting the keys does not gain extra security */ 925 /* explicit_bzero(enc->iv, enc->block_size); 926 explicit_bzero(enc->key, enc->key_len); 927 explicit_bzero(mac->key, mac->key_len); */ 928 if ((comp->type == COMP_ZLIB || 929 (comp->type == COMP_DELAYED && 930 state->after_authentication)) && comp->enabled == 0) { 931 if ((r = ssh_packet_init_compression(ssh)) < 0) 932 return r; 933 if (mode == MODE_OUT) { 934 if ((r = start_compression_out(ssh, 6)) != 0) 935 return r; 936 } else { 937 if ((r = start_compression_in(ssh)) != 0) 938 return r; 939 } 940 comp->enabled = 1; 941 } 942 /* 943 * The 2^(blocksize*2) limit is too expensive for 3DES, 944 * so enforce a 1GB limit for small blocksizes. 945 * See RFC4344 section 3.2. 946 */ 947 if (enc->block_size >= 16) 948 *max_blocks = (u_int64_t)1 << (enc->block_size*2); 949 else 950 *max_blocks = ((u_int64_t)1 << 30) / enc->block_size; 951 if (state->rekey_limit) 952 *max_blocks = MINIMUM(*max_blocks, 953 state->rekey_limit / enc->block_size); 954 debug("rekey %s after %llu blocks", dir, 955 (unsigned long long)*max_blocks); 956 return 0; 957 } 958 959 #define MAX_PACKETS (1U<<31) 960 static int 961 ssh_packet_need_rekeying(struct ssh *ssh, u_int outbound_packet_len) 962 { 963 struct session_state *state = ssh->state; 964 u_int32_t out_blocks; 965 966 /* XXX client can't cope with rekeying pre-auth */ 967 if (!state->after_authentication) 968 return 0; 969 970 /* Haven't keyed yet or KEX in progress. */ 971 if (ssh_packet_is_rekeying(ssh)) 972 return 0; 973 974 /* Peer can't rekey */ 975 if (ssh->compat & SSH_BUG_NOREKEY) 976 return 0; 977 978 /* 979 * Permit one packet in or out per rekey - this allows us to 980 * make progress when rekey limits are very small. 981 */ 982 if (state->p_send.packets == 0 && state->p_read.packets == 0) 983 return 0; 984 985 /* Time-based rekeying */ 986 if (state->rekey_interval != 0 && 987 (int64_t)state->rekey_time + state->rekey_interval <= monotime()) 988 return 1; 989 990 /* 991 * Always rekey when MAX_PACKETS sent in either direction 992 * As per RFC4344 section 3.1 we do this after 2^31 packets. 993 */ 994 if (state->p_send.packets > MAX_PACKETS || 995 state->p_read.packets > MAX_PACKETS) 996 return 1; 997 998 /* Rekey after (cipher-specific) maximum blocks */ 999 out_blocks = ROUNDUP(outbound_packet_len, 1000 state->newkeys[MODE_OUT]->enc.block_size); 1001 return (state->max_blocks_out && 1002 (state->p_send.blocks + out_blocks > state->max_blocks_out)) || 1003 (state->max_blocks_in && 1004 (state->p_read.blocks > state->max_blocks_in)); 1005 } 1006 1007 int 1008 ssh_packet_check_rekey(struct ssh *ssh) 1009 { 1010 if (!ssh_packet_need_rekeying(ssh, 0)) 1011 return 0; 1012 debug3_f("rekex triggered"); 1013 return kex_start_rekex(ssh); 1014 } 1015 1016 /* 1017 * Delayed compression for SSH2 is enabled after authentication: 1018 * This happens on the server side after a SSH2_MSG_USERAUTH_SUCCESS is sent, 1019 * and on the client side after a SSH2_MSG_USERAUTH_SUCCESS is received. 1020 */ 1021 static int 1022 ssh_packet_enable_delayed_compress(struct ssh *ssh) 1023 { 1024 struct session_state *state = ssh->state; 1025 struct sshcomp *comp = NULL; 1026 int r, mode; 1027 1028 /* 1029 * Remember that we are past the authentication step, so rekeying 1030 * with COMP_DELAYED will turn on compression immediately. 1031 */ 1032 state->after_authentication = 1; 1033 for (mode = 0; mode < MODE_MAX; mode++) { 1034 /* protocol error: USERAUTH_SUCCESS received before NEWKEYS */ 1035 if (state->newkeys[mode] == NULL) 1036 continue; 1037 comp = &state->newkeys[mode]->comp; 1038 if (comp && !comp->enabled && comp->type == COMP_DELAYED) { 1039 if ((r = ssh_packet_init_compression(ssh)) != 0) 1040 return r; 1041 if (mode == MODE_OUT) { 1042 if ((r = start_compression_out(ssh, 6)) != 0) 1043 return r; 1044 } else { 1045 if ((r = start_compression_in(ssh)) != 0) 1046 return r; 1047 } 1048 comp->enabled = 1; 1049 } 1050 } 1051 return 0; 1052 } 1053 1054 /* Used to mute debug logging for noisy packet types */ 1055 int 1056 ssh_packet_log_type(u_char type) 1057 { 1058 switch (type) { 1059 case SSH2_MSG_CHANNEL_DATA: 1060 case SSH2_MSG_CHANNEL_EXTENDED_DATA: 1061 case SSH2_MSG_CHANNEL_WINDOW_ADJUST: 1062 return 0; 1063 default: 1064 return 1; 1065 } 1066 } 1067 1068 /* 1069 * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue) 1070 */ 1071 int 1072 ssh_packet_send2_wrapped(struct ssh *ssh) 1073 { 1074 struct session_state *state = ssh->state; 1075 u_char type, *cp, macbuf[SSH_DIGEST_MAX_LENGTH]; 1076 u_char tmp, padlen, pad = 0; 1077 u_int authlen = 0, aadlen = 0; 1078 u_int len; 1079 struct sshenc *enc = NULL; 1080 struct sshmac *mac = NULL; 1081 struct sshcomp *comp = NULL; 1082 int r, block_size; 1083 1084 if (state->newkeys[MODE_OUT] != NULL) { 1085 enc = &state->newkeys[MODE_OUT]->enc; 1086 mac = &state->newkeys[MODE_OUT]->mac; 1087 comp = &state->newkeys[MODE_OUT]->comp; 1088 /* disable mac for authenticated encryption */ 1089 if ((authlen = cipher_authlen(enc->cipher)) != 0) 1090 mac = NULL; 1091 } 1092 block_size = enc ? enc->block_size : 8; 1093 aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0; 1094 1095 type = (sshbuf_ptr(state->outgoing_packet))[5]; 1096 if (ssh_packet_log_type(type)) 1097 debug3("send packet: type %u", type); 1098 #ifdef PACKET_DEBUG 1099 fprintf(stderr, "plain: "); 1100 sshbuf_dump(state->outgoing_packet, stderr); 1101 #endif 1102 1103 if (comp && comp->enabled) { 1104 len = sshbuf_len(state->outgoing_packet); 1105 /* skip header, compress only payload */ 1106 if ((r = sshbuf_consume(state->outgoing_packet, 5)) != 0) 1107 goto out; 1108 sshbuf_reset(state->compression_buffer); 1109 if ((r = compress_buffer(ssh, state->outgoing_packet, 1110 state->compression_buffer)) != 0) 1111 goto out; 1112 sshbuf_reset(state->outgoing_packet); 1113 if ((r = sshbuf_put(state->outgoing_packet, 1114 "\0\0\0\0\0", 5)) != 0 || 1115 (r = sshbuf_putb(state->outgoing_packet, 1116 state->compression_buffer)) != 0) 1117 goto out; 1118 DBG(debug("compression: raw %d compressed %zd", len, 1119 sshbuf_len(state->outgoing_packet))); 1120 } 1121 1122 /* sizeof (packet_len + pad_len + payload) */ 1123 len = sshbuf_len(state->outgoing_packet); 1124 1125 /* 1126 * calc size of padding, alloc space, get random data, 1127 * minimum padding is 4 bytes 1128 */ 1129 len -= aadlen; /* packet length is not encrypted for EtM modes */ 1130 padlen = block_size - (len % block_size); 1131 if (padlen < 4) 1132 padlen += block_size; 1133 if (state->extra_pad) { 1134 tmp = state->extra_pad; 1135 state->extra_pad = 1136 ROUNDUP(state->extra_pad, block_size); 1137 /* check if roundup overflowed */ 1138 if (state->extra_pad < tmp) 1139 return SSH_ERR_INVALID_ARGUMENT; 1140 tmp = (len + padlen) % state->extra_pad; 1141 /* Check whether pad calculation below will underflow */ 1142 if (tmp > state->extra_pad) 1143 return SSH_ERR_INVALID_ARGUMENT; 1144 pad = state->extra_pad - tmp; 1145 DBG(debug3_f("adding %d (len %d padlen %d extra_pad %d)", 1146 pad, len, padlen, state->extra_pad)); 1147 tmp = padlen; 1148 padlen += pad; 1149 /* Check whether padlen calculation overflowed */ 1150 if (padlen < tmp) 1151 return SSH_ERR_INVALID_ARGUMENT; /* overflow */ 1152 state->extra_pad = 0; 1153 } 1154 if ((r = sshbuf_reserve(state->outgoing_packet, padlen, &cp)) != 0) 1155 goto out; 1156 if (enc && !cipher_ctx_is_plaintext(state->send_context)) { 1157 /* random padding */ 1158 arc4random_buf(cp, padlen); 1159 } else { 1160 /* clear padding */ 1161 explicit_bzero(cp, padlen); 1162 } 1163 /* sizeof (packet_len + pad_len + payload + padding) */ 1164 len = sshbuf_len(state->outgoing_packet); 1165 cp = sshbuf_mutable_ptr(state->outgoing_packet); 1166 if (cp == NULL) { 1167 r = SSH_ERR_INTERNAL_ERROR; 1168 goto out; 1169 } 1170 /* packet_length includes payload, padding and padding length field */ 1171 POKE_U32(cp, len - 4); 1172 cp[4] = padlen; 1173 DBG(debug("send: len %d (includes padlen %d, aadlen %d)", 1174 len, padlen, aadlen)); 1175 1176 /* compute MAC over seqnr and packet(length fields, payload, padding) */ 1177 if (mac && mac->enabled && !mac->etm) { 1178 if ((r = mac_compute(mac, state->p_send.seqnr, 1179 sshbuf_ptr(state->outgoing_packet), len, 1180 macbuf, sizeof(macbuf))) != 0) 1181 goto out; 1182 DBG(debug("done calc MAC out #%d", state->p_send.seqnr)); 1183 } 1184 /* encrypt packet and append to output buffer. */ 1185 if ((r = sshbuf_reserve(state->output, 1186 sshbuf_len(state->outgoing_packet) + authlen, &cp)) != 0) 1187 goto out; 1188 if ((r = cipher_crypt(state->send_context, state->p_send.seqnr, cp, 1189 sshbuf_ptr(state->outgoing_packet), 1190 len - aadlen, aadlen, authlen)) != 0) 1191 goto out; 1192 /* append unencrypted MAC */ 1193 if (mac && mac->enabled) { 1194 if (mac->etm) { 1195 /* EtM: compute mac over aadlen + cipher text */ 1196 if ((r = mac_compute(mac, state->p_send.seqnr, 1197 cp, len, macbuf, sizeof(macbuf))) != 0) 1198 goto out; 1199 DBG(debug("done calc MAC(EtM) out #%d", 1200 state->p_send.seqnr)); 1201 } 1202 if ((r = sshbuf_put(state->output, macbuf, mac->mac_len)) != 0) 1203 goto out; 1204 } 1205 #ifdef PACKET_DEBUG 1206 fprintf(stderr, "encrypted: "); 1207 sshbuf_dump(state->output, stderr); 1208 #endif 1209 /* increment sequence number for outgoing packets */ 1210 if (++state->p_send.seqnr == 0) 1211 logit("outgoing seqnr wraps around"); 1212 if (++state->p_send.packets == 0) 1213 if (!(ssh->compat & SSH_BUG_NOREKEY)) 1214 return SSH_ERR_NEED_REKEY; 1215 state->p_send.blocks += len / block_size; 1216 state->p_send.bytes += len; 1217 sshbuf_reset(state->outgoing_packet); 1218 1219 if (type == SSH2_MSG_NEWKEYS) 1220 r = ssh_set_newkeys(ssh, MODE_OUT); 1221 else if (type == SSH2_MSG_USERAUTH_SUCCESS && state->server_side) 1222 r = ssh_packet_enable_delayed_compress(ssh); 1223 else 1224 r = 0; 1225 out: 1226 return r; 1227 } 1228 1229 /* returns non-zero if the specified packet type is usec by KEX */ 1230 static int 1231 ssh_packet_type_is_kex(u_char type) 1232 { 1233 return 1234 type >= SSH2_MSG_TRANSPORT_MIN && 1235 type <= SSH2_MSG_TRANSPORT_MAX && 1236 type != SSH2_MSG_SERVICE_REQUEST && 1237 type != SSH2_MSG_SERVICE_ACCEPT && 1238 type != SSH2_MSG_EXT_INFO; 1239 } 1240 1241 int 1242 ssh_packet_send2(struct ssh *ssh) 1243 { 1244 struct session_state *state = ssh->state; 1245 struct packet *p; 1246 u_char type; 1247 int r, need_rekey; 1248 1249 if (sshbuf_len(state->outgoing_packet) < 6) 1250 return SSH_ERR_INTERNAL_ERROR; 1251 type = sshbuf_ptr(state->outgoing_packet)[5]; 1252 need_rekey = !ssh_packet_type_is_kex(type) && 1253 ssh_packet_need_rekeying(ssh, sshbuf_len(state->outgoing_packet)); 1254 1255 /* 1256 * During rekeying we can only send key exchange messages. 1257 * Queue everything else. 1258 */ 1259 if ((need_rekey || state->rekeying) && !ssh_packet_type_is_kex(type)) { 1260 if (need_rekey) 1261 debug3_f("rekex triggered"); 1262 debug("enqueue packet: %u", type); 1263 p = calloc(1, sizeof(*p)); 1264 if (p == NULL) 1265 return SSH_ERR_ALLOC_FAIL; 1266 p->type = type; 1267 p->payload = state->outgoing_packet; 1268 TAILQ_INSERT_TAIL(&state->outgoing, p, next); 1269 state->outgoing_packet = sshbuf_new(); 1270 if (state->outgoing_packet == NULL) 1271 return SSH_ERR_ALLOC_FAIL; 1272 if (need_rekey) { 1273 /* 1274 * This packet triggered a rekey, so send the 1275 * KEXINIT now. 1276 * NB. reenters this function via kex_start_rekex(). 1277 */ 1278 return kex_start_rekex(ssh); 1279 } 1280 return 0; 1281 } 1282 1283 /* rekeying starts with sending KEXINIT */ 1284 if (type == SSH2_MSG_KEXINIT) 1285 state->rekeying = 1; 1286 1287 if ((r = ssh_packet_send2_wrapped(ssh)) != 0) 1288 return r; 1289 1290 /* after a NEWKEYS message we can send the complete queue */ 1291 if (type == SSH2_MSG_NEWKEYS) { 1292 state->rekeying = 0; 1293 state->rekey_time = monotime(); 1294 while ((p = TAILQ_FIRST(&state->outgoing))) { 1295 type = p->type; 1296 /* 1297 * If this packet triggers a rekex, then skip the 1298 * remaining packets in the queue for now. 1299 * NB. re-enters this function via kex_start_rekex. 1300 */ 1301 if (ssh_packet_need_rekeying(ssh, 1302 sshbuf_len(p->payload))) { 1303 debug3_f("queued packet triggered rekex"); 1304 return kex_start_rekex(ssh); 1305 } 1306 debug("dequeue packet: %u", type); 1307 sshbuf_free(state->outgoing_packet); 1308 state->outgoing_packet = p->payload; 1309 TAILQ_REMOVE(&state->outgoing, p, next); 1310 memset(p, 0, sizeof(*p)); 1311 free(p); 1312 if ((r = ssh_packet_send2_wrapped(ssh)) != 0) 1313 return r; 1314 } 1315 } 1316 return 0; 1317 } 1318 1319 /* 1320 * Waits until a packet has been received, and returns its type. Note that 1321 * no other data is processed until this returns, so this function should not 1322 * be used during the interactive session. 1323 */ 1324 1325 int 1326 ssh_packet_read_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1327 { 1328 struct session_state *state = ssh->state; 1329 int len, r, ms_remain; 1330 fd_set *setp; 1331 char buf[8192]; 1332 struct timeval timeout, start, *timeoutp = NULL; 1333 1334 DBG(debug("packet_read()")); 1335 1336 setp = calloc(howmany(state->connection_in + 1, 1337 NFDBITS), sizeof(fd_mask)); 1338 if (setp == NULL) 1339 return SSH_ERR_ALLOC_FAIL; 1340 1341 /* 1342 * Since we are blocking, ensure that all written packets have 1343 * been sent. 1344 */ 1345 if ((r = ssh_packet_write_wait(ssh)) != 0) 1346 goto out; 1347 1348 /* Stay in the loop until we have received a complete packet. */ 1349 for (;;) { 1350 /* Try to read a packet from the buffer. */ 1351 r = ssh_packet_read_poll_seqnr(ssh, typep, seqnr_p); 1352 if (r != 0) 1353 break; 1354 /* If we got a packet, return it. */ 1355 if (*typep != SSH_MSG_NONE) 1356 break; 1357 /* 1358 * Otherwise, wait for some data to arrive, add it to the 1359 * buffer, and try again. 1360 */ 1361 memset(setp, 0, howmany(state->connection_in + 1, 1362 NFDBITS) * sizeof(fd_mask)); 1363 FD_SET(state->connection_in, setp); 1364 1365 if (state->packet_timeout_ms > 0) { 1366 ms_remain = state->packet_timeout_ms; 1367 timeoutp = &timeout; 1368 } 1369 /* Wait for some data to arrive. */ 1370 for (;;) { 1371 if (state->packet_timeout_ms > 0) { 1372 ms_to_timeval(&timeout, ms_remain); 1373 monotime_tv(&start); 1374 } 1375 if ((r = select(state->connection_in + 1, setp, 1376 NULL, NULL, timeoutp)) >= 0) 1377 break; 1378 if (errno != EAGAIN && errno != EINTR && 1379 errno != EWOULDBLOCK) { 1380 r = SSH_ERR_SYSTEM_ERROR; 1381 goto out; 1382 } 1383 if (state->packet_timeout_ms <= 0) 1384 continue; 1385 ms_subtract_diff(&start, &ms_remain); 1386 if (ms_remain <= 0) { 1387 r = 0; 1388 break; 1389 } 1390 } 1391 if (r == 0) { 1392 r = SSH_ERR_CONN_TIMEOUT; 1393 goto out; 1394 } 1395 /* Read data from the socket. */ 1396 len = read(state->connection_in, buf, sizeof(buf)); 1397 if (len == 0) { 1398 r = SSH_ERR_CONN_CLOSED; 1399 goto out; 1400 } 1401 if (len == -1) { 1402 r = SSH_ERR_SYSTEM_ERROR; 1403 goto out; 1404 } 1405 1406 /* Append it to the buffer. */ 1407 if ((r = ssh_packet_process_incoming(ssh, buf, len)) != 0) 1408 goto out; 1409 } 1410 out: 1411 free(setp); 1412 return r; 1413 } 1414 1415 int 1416 ssh_packet_read(struct ssh *ssh) 1417 { 1418 u_char type; 1419 int r; 1420 1421 if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0) 1422 fatal_fr(r, "read"); 1423 return type; 1424 } 1425 1426 /* 1427 * Waits until a packet has been received, verifies that its type matches 1428 * that given, and gives a fatal error and exits if there is a mismatch. 1429 */ 1430 1431 int 1432 ssh_packet_read_expect(struct ssh *ssh, u_int expected_type) 1433 { 1434 int r; 1435 u_char type; 1436 1437 if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0) 1438 return r; 1439 if (type != expected_type) { 1440 if ((r = sshpkt_disconnect(ssh, 1441 "Protocol error: expected packet type %d, got %d", 1442 expected_type, type)) != 0) 1443 return r; 1444 return SSH_ERR_PROTOCOL_ERROR; 1445 } 1446 return 0; 1447 } 1448 1449 static int 1450 ssh_packet_read_poll2_mux(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1451 { 1452 struct session_state *state = ssh->state; 1453 const u_char *cp; 1454 size_t need; 1455 int r; 1456 1457 if (ssh->kex) 1458 return SSH_ERR_INTERNAL_ERROR; 1459 *typep = SSH_MSG_NONE; 1460 cp = sshbuf_ptr(state->input); 1461 if (state->packlen == 0) { 1462 if (sshbuf_len(state->input) < 4 + 1) 1463 return 0; /* packet is incomplete */ 1464 state->packlen = PEEK_U32(cp); 1465 if (state->packlen < 4 + 1 || 1466 state->packlen > PACKET_MAX_SIZE) 1467 return SSH_ERR_MESSAGE_INCOMPLETE; 1468 } 1469 need = state->packlen + 4; 1470 if (sshbuf_len(state->input) < need) 1471 return 0; /* packet is incomplete */ 1472 sshbuf_reset(state->incoming_packet); 1473 if ((r = sshbuf_put(state->incoming_packet, cp + 4, 1474 state->packlen)) != 0 || 1475 (r = sshbuf_consume(state->input, need)) != 0 || 1476 (r = sshbuf_get_u8(state->incoming_packet, NULL)) != 0 || 1477 (r = sshbuf_get_u8(state->incoming_packet, typep)) != 0) 1478 return r; 1479 if (ssh_packet_log_type(*typep)) 1480 debug3_f("type %u", *typep); 1481 /* sshbuf_dump(state->incoming_packet, stderr); */ 1482 /* reset for next packet */ 1483 state->packlen = 0; 1484 return r; 1485 } 1486 1487 int 1488 ssh_packet_read_poll2(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1489 { 1490 struct session_state *state = ssh->state; 1491 u_int padlen, need; 1492 u_char *cp; 1493 u_int maclen, aadlen = 0, authlen = 0, block_size; 1494 struct sshenc *enc = NULL; 1495 struct sshmac *mac = NULL; 1496 struct sshcomp *comp = NULL; 1497 int r; 1498 1499 if (state->mux) 1500 return ssh_packet_read_poll2_mux(ssh, typep, seqnr_p); 1501 1502 *typep = SSH_MSG_NONE; 1503 1504 if (state->packet_discard) 1505 return 0; 1506 1507 if (state->newkeys[MODE_IN] != NULL) { 1508 enc = &state->newkeys[MODE_IN]->enc; 1509 mac = &state->newkeys[MODE_IN]->mac; 1510 comp = &state->newkeys[MODE_IN]->comp; 1511 /* disable mac for authenticated encryption */ 1512 if ((authlen = cipher_authlen(enc->cipher)) != 0) 1513 mac = NULL; 1514 } 1515 maclen = mac && mac->enabled ? mac->mac_len : 0; 1516 block_size = enc ? enc->block_size : 8; 1517 aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0; 1518 1519 if (aadlen && state->packlen == 0) { 1520 if (cipher_get_length(state->receive_context, 1521 &state->packlen, state->p_read.seqnr, 1522 sshbuf_ptr(state->input), sshbuf_len(state->input)) != 0) 1523 return 0; 1524 if (state->packlen < 1 + 4 || 1525 state->packlen > PACKET_MAX_SIZE) { 1526 #ifdef PACKET_DEBUG 1527 sshbuf_dump(state->input, stderr); 1528 #endif 1529 logit("Bad packet length %u.", state->packlen); 1530 if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0) 1531 return r; 1532 return SSH_ERR_CONN_CORRUPT; 1533 } 1534 sshbuf_reset(state->incoming_packet); 1535 } else if (state->packlen == 0) { 1536 /* 1537 * check if input size is less than the cipher block size, 1538 * decrypt first block and extract length of incoming packet 1539 */ 1540 if (sshbuf_len(state->input) < block_size) 1541 return 0; 1542 sshbuf_reset(state->incoming_packet); 1543 if ((r = sshbuf_reserve(state->incoming_packet, block_size, 1544 &cp)) != 0) 1545 goto out; 1546 if ((r = cipher_crypt(state->receive_context, 1547 state->p_send.seqnr, cp, sshbuf_ptr(state->input), 1548 block_size, 0, 0)) != 0) 1549 goto out; 1550 state->packlen = PEEK_U32(sshbuf_ptr(state->incoming_packet)); 1551 if (state->packlen < 1 + 4 || 1552 state->packlen > PACKET_MAX_SIZE) { 1553 #ifdef PACKET_DEBUG 1554 fprintf(stderr, "input: \n"); 1555 sshbuf_dump(state->input, stderr); 1556 fprintf(stderr, "incoming_packet: \n"); 1557 sshbuf_dump(state->incoming_packet, stderr); 1558 #endif 1559 logit("Bad packet length %u.", state->packlen); 1560 return ssh_packet_start_discard(ssh, enc, mac, 0, 1561 PACKET_MAX_SIZE); 1562 } 1563 if ((r = sshbuf_consume(state->input, block_size)) != 0) 1564 goto out; 1565 } 1566 DBG(debug("input: packet len %u", state->packlen+4)); 1567 1568 if (aadlen) { 1569 /* only the payload is encrypted */ 1570 need = state->packlen; 1571 } else { 1572 /* 1573 * the payload size and the payload are encrypted, but we 1574 * have a partial packet of block_size bytes 1575 */ 1576 need = 4 + state->packlen - block_size; 1577 } 1578 DBG(debug("partial packet: block %d, need %d, maclen %d, authlen %d," 1579 " aadlen %d", block_size, need, maclen, authlen, aadlen)); 1580 if (need % block_size != 0) { 1581 logit("padding error: need %d block %d mod %d", 1582 need, block_size, need % block_size); 1583 return ssh_packet_start_discard(ssh, enc, mac, 0, 1584 PACKET_MAX_SIZE - block_size); 1585 } 1586 /* 1587 * check if the entire packet has been received and 1588 * decrypt into incoming_packet: 1589 * 'aadlen' bytes are unencrypted, but authenticated. 1590 * 'need' bytes are encrypted, followed by either 1591 * 'authlen' bytes of authentication tag or 1592 * 'maclen' bytes of message authentication code. 1593 */ 1594 if (sshbuf_len(state->input) < aadlen + need + authlen + maclen) 1595 return 0; /* packet is incomplete */ 1596 #ifdef PACKET_DEBUG 1597 fprintf(stderr, "read_poll enc/full: "); 1598 sshbuf_dump(state->input, stderr); 1599 #endif 1600 /* EtM: check mac over encrypted input */ 1601 if (mac && mac->enabled && mac->etm) { 1602 if ((r = mac_check(mac, state->p_read.seqnr, 1603 sshbuf_ptr(state->input), aadlen + need, 1604 sshbuf_ptr(state->input) + aadlen + need + authlen, 1605 maclen)) != 0) { 1606 if (r == SSH_ERR_MAC_INVALID) 1607 logit("Corrupted MAC on input."); 1608 goto out; 1609 } 1610 } 1611 if ((r = sshbuf_reserve(state->incoming_packet, aadlen + need, 1612 &cp)) != 0) 1613 goto out; 1614 if ((r = cipher_crypt(state->receive_context, state->p_read.seqnr, cp, 1615 sshbuf_ptr(state->input), need, aadlen, authlen)) != 0) 1616 goto out; 1617 if ((r = sshbuf_consume(state->input, aadlen + need + authlen)) != 0) 1618 goto out; 1619 if (mac && mac->enabled) { 1620 /* Not EtM: check MAC over cleartext */ 1621 if (!mac->etm && (r = mac_check(mac, state->p_read.seqnr, 1622 sshbuf_ptr(state->incoming_packet), 1623 sshbuf_len(state->incoming_packet), 1624 sshbuf_ptr(state->input), maclen)) != 0) { 1625 if (r != SSH_ERR_MAC_INVALID) 1626 goto out; 1627 logit("Corrupted MAC on input."); 1628 if (need + block_size > PACKET_MAX_SIZE) 1629 return SSH_ERR_INTERNAL_ERROR; 1630 return ssh_packet_start_discard(ssh, enc, mac, 1631 sshbuf_len(state->incoming_packet), 1632 PACKET_MAX_SIZE - need - block_size); 1633 } 1634 /* Remove MAC from input buffer */ 1635 DBG(debug("MAC #%d ok", state->p_read.seqnr)); 1636 if ((r = sshbuf_consume(state->input, mac->mac_len)) != 0) 1637 goto out; 1638 } 1639 if (seqnr_p != NULL) 1640 *seqnr_p = state->p_read.seqnr; 1641 if (++state->p_read.seqnr == 0) 1642 logit("incoming seqnr wraps around"); 1643 if (++state->p_read.packets == 0) 1644 if (!(ssh->compat & SSH_BUG_NOREKEY)) 1645 return SSH_ERR_NEED_REKEY; 1646 state->p_read.blocks += (state->packlen + 4) / block_size; 1647 state->p_read.bytes += state->packlen + 4; 1648 1649 /* get padlen */ 1650 padlen = sshbuf_ptr(state->incoming_packet)[4]; 1651 DBG(debug("input: padlen %d", padlen)); 1652 if (padlen < 4) { 1653 if ((r = sshpkt_disconnect(ssh, 1654 "Corrupted padlen %d on input.", padlen)) != 0 || 1655 (r = ssh_packet_write_wait(ssh)) != 0) 1656 return r; 1657 return SSH_ERR_CONN_CORRUPT; 1658 } 1659 1660 /* skip packet size + padlen, discard padding */ 1661 if ((r = sshbuf_consume(state->incoming_packet, 4 + 1)) != 0 || 1662 ((r = sshbuf_consume_end(state->incoming_packet, padlen)) != 0)) 1663 goto out; 1664 1665 DBG(debug("input: len before de-compress %zd", 1666 sshbuf_len(state->incoming_packet))); 1667 if (comp && comp->enabled) { 1668 sshbuf_reset(state->compression_buffer); 1669 if ((r = uncompress_buffer(ssh, state->incoming_packet, 1670 state->compression_buffer)) != 0) 1671 goto out; 1672 sshbuf_reset(state->incoming_packet); 1673 if ((r = sshbuf_putb(state->incoming_packet, 1674 state->compression_buffer)) != 0) 1675 goto out; 1676 DBG(debug("input: len after de-compress %zd", 1677 sshbuf_len(state->incoming_packet))); 1678 } 1679 /* 1680 * get packet type, implies consume. 1681 * return length of payload (without type field) 1682 */ 1683 if ((r = sshbuf_get_u8(state->incoming_packet, typep)) != 0) 1684 goto out; 1685 if (ssh_packet_log_type(*typep)) 1686 debug3("receive packet: type %u", *typep); 1687 if (*typep < SSH2_MSG_MIN || *typep >= SSH2_MSG_LOCAL_MIN) { 1688 if ((r = sshpkt_disconnect(ssh, 1689 "Invalid ssh2 packet type: %d", *typep)) != 0 || 1690 (r = ssh_packet_write_wait(ssh)) != 0) 1691 return r; 1692 return SSH_ERR_PROTOCOL_ERROR; 1693 } 1694 if (state->hook_in != NULL && 1695 (r = state->hook_in(ssh, state->incoming_packet, typep, 1696 state->hook_in_ctx)) != 0) 1697 return r; 1698 if (*typep == SSH2_MSG_USERAUTH_SUCCESS && !state->server_side) 1699 r = ssh_packet_enable_delayed_compress(ssh); 1700 else 1701 r = 0; 1702 #ifdef PACKET_DEBUG 1703 fprintf(stderr, "read/plain[%d]:\r\n", *typep); 1704 sshbuf_dump(state->incoming_packet, stderr); 1705 #endif 1706 /* reset for next packet */ 1707 state->packlen = 0; 1708 1709 if ((r = ssh_packet_check_rekey(ssh)) != 0) 1710 return r; 1711 out: 1712 return r; 1713 } 1714 1715 int 1716 ssh_packet_read_poll_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1717 { 1718 struct session_state *state = ssh->state; 1719 u_int reason, seqnr; 1720 int r; 1721 u_char *msg; 1722 1723 for (;;) { 1724 msg = NULL; 1725 r = ssh_packet_read_poll2(ssh, typep, seqnr_p); 1726 if (r != 0) 1727 return r; 1728 if (*typep) { 1729 state->keep_alive_timeouts = 0; 1730 DBG(debug("received packet type %d", *typep)); 1731 } 1732 switch (*typep) { 1733 case SSH2_MSG_IGNORE: 1734 debug3("Received SSH2_MSG_IGNORE"); 1735 break; 1736 case SSH2_MSG_DEBUG: 1737 if ((r = sshpkt_get_u8(ssh, NULL)) != 0 || 1738 (r = sshpkt_get_string(ssh, &msg, NULL)) != 0 || 1739 (r = sshpkt_get_string(ssh, NULL, NULL)) != 0) { 1740 free(msg); 1741 return r; 1742 } 1743 debug("Remote: %.900s", msg); 1744 free(msg); 1745 break; 1746 case SSH2_MSG_DISCONNECT: 1747 if ((r = sshpkt_get_u32(ssh, &reason)) != 0 || 1748 (r = sshpkt_get_string(ssh, &msg, NULL)) != 0) 1749 return r; 1750 /* Ignore normal client exit notifications */ 1751 do_log2(ssh->state->server_side && 1752 reason == SSH2_DISCONNECT_BY_APPLICATION ? 1753 SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_ERROR, 1754 "Received disconnect from %s port %d:" 1755 "%u: %.400s", ssh_remote_ipaddr(ssh), 1756 ssh_remote_port(ssh), reason, msg); 1757 free(msg); 1758 return SSH_ERR_DISCONNECTED; 1759 case SSH2_MSG_UNIMPLEMENTED: 1760 if ((r = sshpkt_get_u32(ssh, &seqnr)) != 0) 1761 return r; 1762 debug("Received SSH2_MSG_UNIMPLEMENTED for %u", 1763 seqnr); 1764 break; 1765 default: 1766 return 0; 1767 } 1768 } 1769 } 1770 1771 /* 1772 * Buffers the given amount of input characters. This is intended to be used 1773 * together with packet_read_poll. 1774 */ 1775 1776 int 1777 ssh_packet_process_incoming(struct ssh *ssh, const char *buf, u_int len) 1778 { 1779 struct session_state *state = ssh->state; 1780 int r; 1781 1782 if (state->packet_discard) { 1783 state->keep_alive_timeouts = 0; /* ?? */ 1784 if (len >= state->packet_discard) { 1785 if ((r = ssh_packet_stop_discard(ssh)) != 0) 1786 return r; 1787 } 1788 state->packet_discard -= len; 1789 return 0; 1790 } 1791 if ((r = sshbuf_put(ssh->state->input, buf, len)) != 0) 1792 return r; 1793 1794 return 0; 1795 } 1796 1797 int 1798 ssh_packet_remaining(struct ssh *ssh) 1799 { 1800 return sshbuf_len(ssh->state->incoming_packet); 1801 } 1802 1803 /* 1804 * Sends a diagnostic message from the server to the client. This message 1805 * can be sent at any time (but not while constructing another message). The 1806 * message is printed immediately, but only if the client is being executed 1807 * in verbose mode. These messages are primarily intended to ease debugging 1808 * authentication problems. The length of the formatted message must not 1809 * exceed 1024 bytes. This will automatically call ssh_packet_write_wait. 1810 */ 1811 void 1812 ssh_packet_send_debug(struct ssh *ssh, const char *fmt,...) 1813 { 1814 char buf[1024]; 1815 va_list args; 1816 int r; 1817 1818 if ((ssh->compat & SSH_BUG_DEBUG)) 1819 return; 1820 1821 va_start(args, fmt); 1822 vsnprintf(buf, sizeof(buf), fmt, args); 1823 va_end(args); 1824 1825 debug3("sending debug message: %s", buf); 1826 1827 if ((r = sshpkt_start(ssh, SSH2_MSG_DEBUG)) != 0 || 1828 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* always display */ 1829 (r = sshpkt_put_cstring(ssh, buf)) != 0 || 1830 (r = sshpkt_put_cstring(ssh, "")) != 0 || 1831 (r = sshpkt_send(ssh)) != 0 || 1832 (r = ssh_packet_write_wait(ssh)) != 0) 1833 fatal_fr(r, "send DEBUG"); 1834 } 1835 1836 void 1837 sshpkt_fmt_connection_id(struct ssh *ssh, char *s, size_t l) 1838 { 1839 snprintf(s, l, "%.200s%s%s port %d", 1840 ssh->log_preamble ? ssh->log_preamble : "", 1841 ssh->log_preamble ? " " : "", 1842 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 1843 } 1844 1845 /* 1846 * Pretty-print connection-terminating errors and exit. 1847 */ 1848 static void 1849 sshpkt_vfatal(struct ssh *ssh, int r, const char *fmt, va_list ap) 1850 { 1851 char *tag = NULL, remote_id[512]; 1852 int oerrno = errno; 1853 1854 sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id)); 1855 1856 switch (r) { 1857 case SSH_ERR_CONN_CLOSED: 1858 ssh_packet_clear_keys(ssh); 1859 logdie("Connection closed by %s", remote_id); 1860 case SSH_ERR_CONN_TIMEOUT: 1861 ssh_packet_clear_keys(ssh); 1862 logdie("Connection %s %s timed out", 1863 ssh->state->server_side ? "from" : "to", remote_id); 1864 case SSH_ERR_DISCONNECTED: 1865 ssh_packet_clear_keys(ssh); 1866 logdie("Disconnected from %s", remote_id); 1867 case SSH_ERR_SYSTEM_ERROR: 1868 if (errno == ECONNRESET) { 1869 ssh_packet_clear_keys(ssh); 1870 logdie("Connection reset by %s", remote_id); 1871 } 1872 /* FALLTHROUGH */ 1873 case SSH_ERR_NO_CIPHER_ALG_MATCH: 1874 case SSH_ERR_NO_MAC_ALG_MATCH: 1875 case SSH_ERR_NO_COMPRESS_ALG_MATCH: 1876 case SSH_ERR_NO_KEX_ALG_MATCH: 1877 case SSH_ERR_NO_HOSTKEY_ALG_MATCH: 1878 if (ssh && ssh->kex && ssh->kex->failed_choice) { 1879 BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL, "ssh"); 1880 ssh_packet_clear_keys(ssh); 1881 errno = oerrno; 1882 logdie("Unable to negotiate with %s: %s. " 1883 "Their offer: %s", remote_id, ssh_err(r), 1884 ssh->kex->failed_choice); 1885 } 1886 /* FALLTHROUGH */ 1887 default: 1888 if (vasprintf(&tag, fmt, ap) == -1) { 1889 ssh_packet_clear_keys(ssh); 1890 logdie_f("could not allocate failure message"); 1891 } 1892 ssh_packet_clear_keys(ssh); 1893 errno = oerrno; 1894 logdie_r(r, "%s%sConnection %s %s", 1895 tag != NULL ? tag : "", tag != NULL ? ": " : "", 1896 ssh->state->server_side ? "from" : "to", remote_id); 1897 } 1898 } 1899 1900 void 1901 sshpkt_fatal(struct ssh *ssh, int r, const char *fmt, ...) 1902 { 1903 va_list ap; 1904 1905 va_start(ap, fmt); 1906 sshpkt_vfatal(ssh, r, fmt, ap); 1907 /* NOTREACHED */ 1908 va_end(ap); 1909 logdie_f("should have exited"); 1910 } 1911 1912 /* 1913 * Logs the error plus constructs and sends a disconnect packet, closes the 1914 * connection, and exits. This function never returns. The error message 1915 * should not contain a newline. The length of the formatted message must 1916 * not exceed 1024 bytes. 1917 */ 1918 void 1919 ssh_packet_disconnect(struct ssh *ssh, const char *fmt,...) 1920 { 1921 char buf[1024], remote_id[512]; 1922 va_list args; 1923 static int disconnecting = 0; 1924 int r; 1925 1926 if (disconnecting) /* Guard against recursive invocations. */ 1927 fatal("packet_disconnect called recursively."); 1928 disconnecting = 1; 1929 1930 /* 1931 * Format the message. Note that the caller must make sure the 1932 * message is of limited size. 1933 */ 1934 sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id)); 1935 va_start(args, fmt); 1936 vsnprintf(buf, sizeof(buf), fmt, args); 1937 va_end(args); 1938 1939 /* Display the error locally */ 1940 logit("Disconnecting %s: %.100s", remote_id, buf); 1941 1942 /* 1943 * Send the disconnect message to the other side, and wait 1944 * for it to get sent. 1945 */ 1946 if ((r = sshpkt_disconnect(ssh, "%s", buf)) != 0) 1947 sshpkt_fatal(ssh, r, "%s", __func__); 1948 1949 if ((r = ssh_packet_write_wait(ssh)) != 0) 1950 sshpkt_fatal(ssh, r, "%s", __func__); 1951 1952 /* Close the connection. */ 1953 ssh_packet_close(ssh); 1954 cleanup_exit(255); 1955 } 1956 1957 /* 1958 * Checks if there is any buffered output, and tries to write some of 1959 * the output. 1960 */ 1961 int 1962 ssh_packet_write_poll(struct ssh *ssh) 1963 { 1964 struct session_state *state = ssh->state; 1965 int len = sshbuf_len(state->output); 1966 int r; 1967 1968 if (len > 0) { 1969 len = write(state->connection_out, 1970 sshbuf_ptr(state->output), len); 1971 if (len == -1) { 1972 if (errno == EINTR || errno == EAGAIN || 1973 errno == EWOULDBLOCK) 1974 return 0; 1975 return SSH_ERR_SYSTEM_ERROR; 1976 } 1977 if (len == 0) 1978 return SSH_ERR_CONN_CLOSED; 1979 if ((r = sshbuf_consume(state->output, len)) != 0) 1980 return r; 1981 } 1982 return 0; 1983 } 1984 1985 /* 1986 * Calls packet_write_poll repeatedly until all pending output data has been 1987 * written. 1988 */ 1989 int 1990 ssh_packet_write_wait(struct ssh *ssh) 1991 { 1992 fd_set *setp; 1993 int ret, r, ms_remain = 0; 1994 struct timeval start, timeout, *timeoutp = NULL; 1995 struct session_state *state = ssh->state; 1996 1997 setp = calloc(howmany(state->connection_out + 1, 1998 NFDBITS), sizeof(fd_mask)); 1999 if (setp == NULL) 2000 return SSH_ERR_ALLOC_FAIL; 2001 if ((r = ssh_packet_write_poll(ssh)) != 0) { 2002 free(setp); 2003 return r; 2004 } 2005 while (ssh_packet_have_data_to_write(ssh)) { 2006 memset(setp, 0, howmany(state->connection_out + 1, 2007 NFDBITS) * sizeof(fd_mask)); 2008 FD_SET(state->connection_out, setp); 2009 2010 if (state->packet_timeout_ms > 0) { 2011 ms_remain = state->packet_timeout_ms; 2012 timeoutp = &timeout; 2013 } 2014 for (;;) { 2015 if (state->packet_timeout_ms > 0) { 2016 ms_to_timeval(&timeout, ms_remain); 2017 monotime_tv(&start); 2018 } 2019 if ((ret = select(state->connection_out + 1, 2020 NULL, setp, NULL, timeoutp)) >= 0) 2021 break; 2022 if (errno != EAGAIN && errno != EINTR && 2023 errno != EWOULDBLOCK) 2024 break; 2025 if (state->packet_timeout_ms <= 0) 2026 continue; 2027 ms_subtract_diff(&start, &ms_remain); 2028 if (ms_remain <= 0) { 2029 ret = 0; 2030 break; 2031 } 2032 } 2033 if (ret == 0) { 2034 free(setp); 2035 return SSH_ERR_CONN_TIMEOUT; 2036 } 2037 if ((r = ssh_packet_write_poll(ssh)) != 0) { 2038 free(setp); 2039 return r; 2040 } 2041 } 2042 free(setp); 2043 return 0; 2044 } 2045 2046 /* Returns true if there is buffered data to write to the connection. */ 2047 2048 int 2049 ssh_packet_have_data_to_write(struct ssh *ssh) 2050 { 2051 return sshbuf_len(ssh->state->output) != 0; 2052 } 2053 2054 /* Returns true if there is not too much data to write to the connection. */ 2055 2056 int 2057 ssh_packet_not_very_much_data_to_write(struct ssh *ssh) 2058 { 2059 if (ssh->state->interactive_mode) 2060 return sshbuf_len(ssh->state->output) < 16384; 2061 else 2062 return sshbuf_len(ssh->state->output) < 128 * 1024; 2063 } 2064 2065 void 2066 ssh_packet_set_tos(struct ssh *ssh, int tos) 2067 { 2068 if (!ssh_packet_connection_is_on_socket(ssh) || tos == INT_MAX) 2069 return; 2070 set_sock_tos(ssh->state->connection_in, tos); 2071 } 2072 2073 /* Informs that the current session is interactive. Sets IP flags for that. */ 2074 2075 void 2076 ssh_packet_set_interactive(struct ssh *ssh, int interactive, int qos_interactive, int qos_bulk) 2077 { 2078 struct session_state *state = ssh->state; 2079 2080 if (state->set_interactive_called) 2081 return; 2082 state->set_interactive_called = 1; 2083 2084 /* Record that we are in interactive mode. */ 2085 state->interactive_mode = interactive; 2086 2087 /* Only set socket options if using a socket. */ 2088 if (!ssh_packet_connection_is_on_socket(ssh)) 2089 return; 2090 set_nodelay(state->connection_in); 2091 ssh_packet_set_tos(ssh, interactive ? qos_interactive : qos_bulk); 2092 } 2093 2094 /* Returns true if the current connection is interactive. */ 2095 2096 int 2097 ssh_packet_is_interactive(struct ssh *ssh) 2098 { 2099 return ssh->state->interactive_mode; 2100 } 2101 2102 int 2103 ssh_packet_set_maxsize(struct ssh *ssh, u_int s) 2104 { 2105 struct session_state *state = ssh->state; 2106 2107 if (state->set_maxsize_called) { 2108 logit("packet_set_maxsize: called twice: old %d new %d", 2109 state->max_packet_size, s); 2110 return -1; 2111 } 2112 if (s < 4 * 1024 || s > 1024 * 1024) { 2113 logit("packet_set_maxsize: bad size %d", s); 2114 return -1; 2115 } 2116 state->set_maxsize_called = 1; 2117 debug("packet_set_maxsize: setting to %d", s); 2118 state->max_packet_size = s; 2119 return s; 2120 } 2121 2122 int 2123 ssh_packet_inc_alive_timeouts(struct ssh *ssh) 2124 { 2125 return ++ssh->state->keep_alive_timeouts; 2126 } 2127 2128 void 2129 ssh_packet_set_alive_timeouts(struct ssh *ssh, int ka) 2130 { 2131 ssh->state->keep_alive_timeouts = ka; 2132 } 2133 2134 u_int 2135 ssh_packet_get_maxsize(struct ssh *ssh) 2136 { 2137 return ssh->state->max_packet_size; 2138 } 2139 2140 void 2141 ssh_packet_set_rekey_limits(struct ssh *ssh, u_int64_t bytes, u_int32_t seconds) 2142 { 2143 debug3("rekey after %llu bytes, %u seconds", (unsigned long long)bytes, 2144 (unsigned int)seconds); 2145 ssh->state->rekey_limit = bytes; 2146 ssh->state->rekey_interval = seconds; 2147 } 2148 2149 time_t 2150 ssh_packet_get_rekey_timeout(struct ssh *ssh) 2151 { 2152 time_t seconds; 2153 2154 seconds = ssh->state->rekey_time + ssh->state->rekey_interval - 2155 monotime(); 2156 return (seconds <= 0 ? 1 : seconds); 2157 } 2158 2159 void 2160 ssh_packet_set_server(struct ssh *ssh) 2161 { 2162 ssh->state->server_side = 1; 2163 ssh->kex->server = 1; /* XXX unify? */ 2164 } 2165 2166 void 2167 ssh_packet_set_authenticated(struct ssh *ssh) 2168 { 2169 ssh->state->after_authentication = 1; 2170 } 2171 2172 void * 2173 ssh_packet_get_input(struct ssh *ssh) 2174 { 2175 return (void *)ssh->state->input; 2176 } 2177 2178 void * 2179 ssh_packet_get_output(struct ssh *ssh) 2180 { 2181 return (void *)ssh->state->output; 2182 } 2183 2184 /* Reset after_authentication and reset compression in post-auth privsep */ 2185 static int 2186 ssh_packet_set_postauth(struct ssh *ssh) 2187 { 2188 int r; 2189 2190 debug_f("called"); 2191 /* This was set in net child, but is not visible in user child */ 2192 ssh->state->after_authentication = 1; 2193 ssh->state->rekeying = 0; 2194 if ((r = ssh_packet_enable_delayed_compress(ssh)) != 0) 2195 return r; 2196 return 0; 2197 } 2198 2199 /* Packet state (de-)serialization for privsep */ 2200 2201 /* turn kex into a blob for packet state serialization */ 2202 static int 2203 kex_to_blob(struct sshbuf *m, struct kex *kex) 2204 { 2205 int r; 2206 2207 if ((r = sshbuf_put_u32(m, kex->we_need)) != 0 || 2208 (r = sshbuf_put_cstring(m, kex->hostkey_alg)) != 0 || 2209 (r = sshbuf_put_u32(m, kex->hostkey_type)) != 0 || 2210 (r = sshbuf_put_u32(m, kex->hostkey_nid)) != 0 || 2211 (r = sshbuf_put_u32(m, kex->kex_type)) != 0 || 2212 (r = sshbuf_put_stringb(m, kex->my)) != 0 || 2213 (r = sshbuf_put_stringb(m, kex->peer)) != 0 || 2214 (r = sshbuf_put_stringb(m, kex->client_version)) != 0 || 2215 (r = sshbuf_put_stringb(m, kex->server_version)) != 0 || 2216 (r = sshbuf_put_stringb(m, kex->session_id)) != 0 || 2217 (r = sshbuf_put_u32(m, kex->flags)) != 0) 2218 return r; 2219 return 0; 2220 } 2221 2222 /* turn key exchange results into a blob for packet state serialization */ 2223 static int 2224 newkeys_to_blob(struct sshbuf *m, struct ssh *ssh, int mode) 2225 { 2226 struct sshbuf *b; 2227 struct sshcipher_ctx *cc; 2228 struct sshcomp *comp; 2229 struct sshenc *enc; 2230 struct sshmac *mac; 2231 struct newkeys *newkey; 2232 int r; 2233 2234 if ((newkey = ssh->state->newkeys[mode]) == NULL) 2235 return SSH_ERR_INTERNAL_ERROR; 2236 enc = &newkey->enc; 2237 mac = &newkey->mac; 2238 comp = &newkey->comp; 2239 cc = (mode == MODE_OUT) ? ssh->state->send_context : 2240 ssh->state->receive_context; 2241 if ((r = cipher_get_keyiv(cc, enc->iv, enc->iv_len)) != 0) 2242 return r; 2243 if ((b = sshbuf_new()) == NULL) 2244 return SSH_ERR_ALLOC_FAIL; 2245 if ((r = sshbuf_put_cstring(b, enc->name)) != 0 || 2246 (r = sshbuf_put_u32(b, enc->enabled)) != 0 || 2247 (r = sshbuf_put_u32(b, enc->block_size)) != 0 || 2248 (r = sshbuf_put_string(b, enc->key, enc->key_len)) != 0 || 2249 (r = sshbuf_put_string(b, enc->iv, enc->iv_len)) != 0) 2250 goto out; 2251 if (cipher_authlen(enc->cipher) == 0) { 2252 if ((r = sshbuf_put_cstring(b, mac->name)) != 0 || 2253 (r = sshbuf_put_u32(b, mac->enabled)) != 0 || 2254 (r = sshbuf_put_string(b, mac->key, mac->key_len)) != 0) 2255 goto out; 2256 } 2257 if ((r = sshbuf_put_u32(b, comp->type)) != 0 || 2258 (r = sshbuf_put_cstring(b, comp->name)) != 0) 2259 goto out; 2260 r = sshbuf_put_stringb(m, b); 2261 out: 2262 sshbuf_free(b); 2263 return r; 2264 } 2265 2266 /* serialize packet state into a blob */ 2267 int 2268 ssh_packet_get_state(struct ssh *ssh, struct sshbuf *m) 2269 { 2270 struct session_state *state = ssh->state; 2271 int r; 2272 2273 if ((r = kex_to_blob(m, ssh->kex)) != 0 || 2274 (r = newkeys_to_blob(m, ssh, MODE_OUT)) != 0 || 2275 (r = newkeys_to_blob(m, ssh, MODE_IN)) != 0 || 2276 (r = sshbuf_put_u64(m, state->rekey_limit)) != 0 || 2277 (r = sshbuf_put_u32(m, state->rekey_interval)) != 0 || 2278 (r = sshbuf_put_u32(m, state->p_send.seqnr)) != 0 || 2279 (r = sshbuf_put_u64(m, state->p_send.blocks)) != 0 || 2280 (r = sshbuf_put_u32(m, state->p_send.packets)) != 0 || 2281 (r = sshbuf_put_u64(m, state->p_send.bytes)) != 0 || 2282 (r = sshbuf_put_u32(m, state->p_read.seqnr)) != 0 || 2283 (r = sshbuf_put_u64(m, state->p_read.blocks)) != 0 || 2284 (r = sshbuf_put_u32(m, state->p_read.packets)) != 0 || 2285 (r = sshbuf_put_u64(m, state->p_read.bytes)) != 0 || 2286 (r = sshbuf_put_stringb(m, state->input)) != 0 || 2287 (r = sshbuf_put_stringb(m, state->output)) != 0) 2288 return r; 2289 2290 return 0; 2291 } 2292 2293 /* restore key exchange results from blob for packet state de-serialization */ 2294 static int 2295 newkeys_from_blob(struct sshbuf *m, struct ssh *ssh, int mode) 2296 { 2297 struct sshbuf *b = NULL; 2298 struct sshcomp *comp; 2299 struct sshenc *enc; 2300 struct sshmac *mac; 2301 struct newkeys *newkey = NULL; 2302 size_t keylen, ivlen, maclen; 2303 int r; 2304 2305 if ((newkey = calloc(1, sizeof(*newkey))) == NULL) { 2306 r = SSH_ERR_ALLOC_FAIL; 2307 goto out; 2308 } 2309 if ((r = sshbuf_froms(m, &b)) != 0) 2310 goto out; 2311 #ifdef DEBUG_PK 2312 sshbuf_dump(b, stderr); 2313 #endif 2314 enc = &newkey->enc; 2315 mac = &newkey->mac; 2316 comp = &newkey->comp; 2317 2318 if ((r = sshbuf_get_cstring(b, &enc->name, NULL)) != 0 || 2319 (r = sshbuf_get_u32(b, (u_int *)&enc->enabled)) != 0 || 2320 (r = sshbuf_get_u32(b, &enc->block_size)) != 0 || 2321 (r = sshbuf_get_string(b, &enc->key, &keylen)) != 0 || 2322 (r = sshbuf_get_string(b, &enc->iv, &ivlen)) != 0) 2323 goto out; 2324 if ((enc->cipher = cipher_by_name(enc->name)) == NULL) { 2325 r = SSH_ERR_INVALID_FORMAT; 2326 goto out; 2327 } 2328 if (cipher_authlen(enc->cipher) == 0) { 2329 if ((r = sshbuf_get_cstring(b, &mac->name, NULL)) != 0) 2330 goto out; 2331 if ((r = mac_setup(mac, mac->name)) != 0) 2332 goto out; 2333 if ((r = sshbuf_get_u32(b, (u_int *)&mac->enabled)) != 0 || 2334 (r = sshbuf_get_string(b, &mac->key, &maclen)) != 0) 2335 goto out; 2336 if (maclen > mac->key_len) { 2337 r = SSH_ERR_INVALID_FORMAT; 2338 goto out; 2339 } 2340 mac->key_len = maclen; 2341 } 2342 if ((r = sshbuf_get_u32(b, &comp->type)) != 0 || 2343 (r = sshbuf_get_cstring(b, &comp->name, NULL)) != 0) 2344 goto out; 2345 if (sshbuf_len(b) != 0) { 2346 r = SSH_ERR_INVALID_FORMAT; 2347 goto out; 2348 } 2349 enc->key_len = keylen; 2350 enc->iv_len = ivlen; 2351 ssh->kex->newkeys[mode] = newkey; 2352 newkey = NULL; 2353 r = 0; 2354 out: 2355 free(newkey); 2356 sshbuf_free(b); 2357 return r; 2358 } 2359 2360 /* restore kex from blob for packet state de-serialization */ 2361 static int 2362 kex_from_blob(struct sshbuf *m, struct kex **kexp) 2363 { 2364 struct kex *kex; 2365 int r; 2366 2367 if ((kex = kex_new()) == NULL) 2368 return SSH_ERR_ALLOC_FAIL; 2369 if ((r = sshbuf_get_u32(m, &kex->we_need)) != 0 || 2370 (r = sshbuf_get_cstring(m, &kex->hostkey_alg, NULL)) != 0 || 2371 (r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_type)) != 0 || 2372 (r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_nid)) != 0 || 2373 (r = sshbuf_get_u32(m, &kex->kex_type)) != 0 || 2374 (r = sshbuf_get_stringb(m, kex->my)) != 0 || 2375 (r = sshbuf_get_stringb(m, kex->peer)) != 0 || 2376 (r = sshbuf_get_stringb(m, kex->client_version)) != 0 || 2377 (r = sshbuf_get_stringb(m, kex->server_version)) != 0 || 2378 (r = sshbuf_get_stringb(m, kex->session_id)) != 0 || 2379 (r = sshbuf_get_u32(m, &kex->flags)) != 0) 2380 goto out; 2381 kex->server = 1; 2382 kex->done = 1; 2383 r = 0; 2384 out: 2385 if (r != 0 || kexp == NULL) { 2386 kex_free(kex); 2387 if (kexp != NULL) 2388 *kexp = NULL; 2389 } else { 2390 kex_free(*kexp); 2391 *kexp = kex; 2392 } 2393 return r; 2394 } 2395 2396 /* 2397 * Restore packet state from content of blob 'm' (de-serialization). 2398 * Note that 'm' will be partially consumed on parsing or any other errors. 2399 */ 2400 int 2401 ssh_packet_set_state(struct ssh *ssh, struct sshbuf *m) 2402 { 2403 struct session_state *state = ssh->state; 2404 const u_char *input, *output; 2405 size_t ilen, olen; 2406 int r; 2407 2408 if ((r = kex_from_blob(m, &ssh->kex)) != 0 || 2409 (r = newkeys_from_blob(m, ssh, MODE_OUT)) != 0 || 2410 (r = newkeys_from_blob(m, ssh, MODE_IN)) != 0 || 2411 (r = sshbuf_get_u64(m, &state->rekey_limit)) != 0 || 2412 (r = sshbuf_get_u32(m, &state->rekey_interval)) != 0 || 2413 (r = sshbuf_get_u32(m, &state->p_send.seqnr)) != 0 || 2414 (r = sshbuf_get_u64(m, &state->p_send.blocks)) != 0 || 2415 (r = sshbuf_get_u32(m, &state->p_send.packets)) != 0 || 2416 (r = sshbuf_get_u64(m, &state->p_send.bytes)) != 0 || 2417 (r = sshbuf_get_u32(m, &state->p_read.seqnr)) != 0 || 2418 (r = sshbuf_get_u64(m, &state->p_read.blocks)) != 0 || 2419 (r = sshbuf_get_u32(m, &state->p_read.packets)) != 0 || 2420 (r = sshbuf_get_u64(m, &state->p_read.bytes)) != 0) 2421 return r; 2422 /* 2423 * We set the time here so that in post-auth privsep child we 2424 * count from the completion of the authentication. 2425 */ 2426 state->rekey_time = monotime(); 2427 /* XXX ssh_set_newkeys overrides p_read.packets? XXX */ 2428 if ((r = ssh_set_newkeys(ssh, MODE_IN)) != 0 || 2429 (r = ssh_set_newkeys(ssh, MODE_OUT)) != 0) 2430 return r; 2431 2432 if ((r = ssh_packet_set_postauth(ssh)) != 0) 2433 return r; 2434 2435 sshbuf_reset(state->input); 2436 sshbuf_reset(state->output); 2437 if ((r = sshbuf_get_string_direct(m, &input, &ilen)) != 0 || 2438 (r = sshbuf_get_string_direct(m, &output, &olen)) != 0 || 2439 (r = sshbuf_put(state->input, input, ilen)) != 0 || 2440 (r = sshbuf_put(state->output, output, olen)) != 0) 2441 return r; 2442 2443 if (sshbuf_len(m)) 2444 return SSH_ERR_INVALID_FORMAT; 2445 debug3_f("done"); 2446 return 0; 2447 } 2448 2449 /* NEW API */ 2450 2451 /* put data to the outgoing packet */ 2452 2453 int 2454 sshpkt_put(struct ssh *ssh, const void *v, size_t len) 2455 { 2456 return sshbuf_put(ssh->state->outgoing_packet, v, len); 2457 } 2458 2459 int 2460 sshpkt_putb(struct ssh *ssh, const struct sshbuf *b) 2461 { 2462 return sshbuf_putb(ssh->state->outgoing_packet, b); 2463 } 2464 2465 int 2466 sshpkt_put_u8(struct ssh *ssh, u_char val) 2467 { 2468 return sshbuf_put_u8(ssh->state->outgoing_packet, val); 2469 } 2470 2471 int 2472 sshpkt_put_u32(struct ssh *ssh, u_int32_t val) 2473 { 2474 return sshbuf_put_u32(ssh->state->outgoing_packet, val); 2475 } 2476 2477 int 2478 sshpkt_put_u64(struct ssh *ssh, u_int64_t val) 2479 { 2480 return sshbuf_put_u64(ssh->state->outgoing_packet, val); 2481 } 2482 2483 int 2484 sshpkt_put_string(struct ssh *ssh, const void *v, size_t len) 2485 { 2486 return sshbuf_put_string(ssh->state->outgoing_packet, v, len); 2487 } 2488 2489 int 2490 sshpkt_put_cstring(struct ssh *ssh, const void *v) 2491 { 2492 return sshbuf_put_cstring(ssh->state->outgoing_packet, v); 2493 } 2494 2495 int 2496 sshpkt_put_stringb(struct ssh *ssh, const struct sshbuf *v) 2497 { 2498 return sshbuf_put_stringb(ssh->state->outgoing_packet, v); 2499 } 2500 2501 int 2502 sshpkt_getb_froms(struct ssh *ssh, struct sshbuf **valp) 2503 { 2504 return sshbuf_froms(ssh->state->incoming_packet, valp); 2505 } 2506 2507 #ifdef WITH_OPENSSL 2508 #ifdef OPENSSL_HAS_ECC 2509 int 2510 sshpkt_put_ec(struct ssh *ssh, const EC_POINT *v, const EC_GROUP *g) 2511 { 2512 return sshbuf_put_ec(ssh->state->outgoing_packet, v, g); 2513 } 2514 #endif /* OPENSSL_HAS_ECC */ 2515 2516 2517 int 2518 sshpkt_put_bignum2(struct ssh *ssh, const BIGNUM *v) 2519 { 2520 return sshbuf_put_bignum2(ssh->state->outgoing_packet, v); 2521 } 2522 #endif /* WITH_OPENSSL */ 2523 2524 /* fetch data from the incoming packet */ 2525 2526 int 2527 sshpkt_get(struct ssh *ssh, void *valp, size_t len) 2528 { 2529 return sshbuf_get(ssh->state->incoming_packet, valp, len); 2530 } 2531 2532 int 2533 sshpkt_get_u8(struct ssh *ssh, u_char *valp) 2534 { 2535 return sshbuf_get_u8(ssh->state->incoming_packet, valp); 2536 } 2537 2538 int 2539 sshpkt_get_u32(struct ssh *ssh, u_int32_t *valp) 2540 { 2541 return sshbuf_get_u32(ssh->state->incoming_packet, valp); 2542 } 2543 2544 int 2545 sshpkt_get_u64(struct ssh *ssh, u_int64_t *valp) 2546 { 2547 return sshbuf_get_u64(ssh->state->incoming_packet, valp); 2548 } 2549 2550 int 2551 sshpkt_get_string(struct ssh *ssh, u_char **valp, size_t *lenp) 2552 { 2553 return sshbuf_get_string(ssh->state->incoming_packet, valp, lenp); 2554 } 2555 2556 int 2557 sshpkt_get_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp) 2558 { 2559 return sshbuf_get_string_direct(ssh->state->incoming_packet, valp, lenp); 2560 } 2561 2562 int 2563 sshpkt_peek_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp) 2564 { 2565 return sshbuf_peek_string_direct(ssh->state->incoming_packet, valp, lenp); 2566 } 2567 2568 int 2569 sshpkt_get_cstring(struct ssh *ssh, char **valp, size_t *lenp) 2570 { 2571 return sshbuf_get_cstring(ssh->state->incoming_packet, valp, lenp); 2572 } 2573 2574 #ifdef WITH_OPENSSL 2575 #ifdef OPENSSL_HAS_ECC 2576 int 2577 sshpkt_get_ec(struct ssh *ssh, EC_POINT *v, const EC_GROUP *g) 2578 { 2579 return sshbuf_get_ec(ssh->state->incoming_packet, v, g); 2580 } 2581 #endif /* OPENSSL_HAS_ECC */ 2582 2583 int 2584 sshpkt_get_bignum2(struct ssh *ssh, BIGNUM **valp) 2585 { 2586 return sshbuf_get_bignum2(ssh->state->incoming_packet, valp); 2587 } 2588 #endif /* WITH_OPENSSL */ 2589 2590 int 2591 sshpkt_get_end(struct ssh *ssh) 2592 { 2593 if (sshbuf_len(ssh->state->incoming_packet) > 0) 2594 return SSH_ERR_UNEXPECTED_TRAILING_DATA; 2595 return 0; 2596 } 2597 2598 const u_char * 2599 sshpkt_ptr(struct ssh *ssh, size_t *lenp) 2600 { 2601 if (lenp != NULL) 2602 *lenp = sshbuf_len(ssh->state->incoming_packet); 2603 return sshbuf_ptr(ssh->state->incoming_packet); 2604 } 2605 2606 /* start a new packet */ 2607 2608 int 2609 sshpkt_start(struct ssh *ssh, u_char type) 2610 { 2611 u_char buf[6]; /* u32 packet length, u8 pad len, u8 type */ 2612 2613 DBG(debug("packet_start[%d]", type)); 2614 memset(buf, 0, sizeof(buf)); 2615 buf[sizeof(buf) - 1] = type; 2616 sshbuf_reset(ssh->state->outgoing_packet); 2617 return sshbuf_put(ssh->state->outgoing_packet, buf, sizeof(buf)); 2618 } 2619 2620 static int 2621 ssh_packet_send_mux(struct ssh *ssh) 2622 { 2623 struct session_state *state = ssh->state; 2624 u_char type, *cp; 2625 size_t len; 2626 int r; 2627 2628 if (ssh->kex) 2629 return SSH_ERR_INTERNAL_ERROR; 2630 len = sshbuf_len(state->outgoing_packet); 2631 if (len < 6) 2632 return SSH_ERR_INTERNAL_ERROR; 2633 cp = sshbuf_mutable_ptr(state->outgoing_packet); 2634 type = cp[5]; 2635 if (ssh_packet_log_type(type)) 2636 debug3_f("type %u", type); 2637 /* drop everything, but the connection protocol */ 2638 if (type >= SSH2_MSG_CONNECTION_MIN && 2639 type <= SSH2_MSG_CONNECTION_MAX) { 2640 POKE_U32(cp, len - 4); 2641 if ((r = sshbuf_putb(state->output, 2642 state->outgoing_packet)) != 0) 2643 return r; 2644 /* sshbuf_dump(state->output, stderr); */ 2645 } 2646 sshbuf_reset(state->outgoing_packet); 2647 return 0; 2648 } 2649 2650 /* 2651 * 9.2. Ignored Data Message 2652 * 2653 * byte SSH_MSG_IGNORE 2654 * string data 2655 * 2656 * All implementations MUST understand (and ignore) this message at any 2657 * time (after receiving the protocol version). No implementation is 2658 * required to send them. This message can be used as an additional 2659 * protection measure against advanced traffic analysis techniques. 2660 */ 2661 int 2662 sshpkt_msg_ignore(struct ssh *ssh, u_int nbytes) 2663 { 2664 u_int32_t rnd = 0; 2665 int r; 2666 u_int i; 2667 2668 if ((r = sshpkt_start(ssh, SSH2_MSG_IGNORE)) != 0 || 2669 (r = sshpkt_put_u32(ssh, nbytes)) != 0) 2670 return r; 2671 for (i = 0; i < nbytes; i++) { 2672 if (i % 4 == 0) 2673 rnd = arc4random(); 2674 if ((r = sshpkt_put_u8(ssh, (u_char)rnd & 0xff)) != 0) 2675 return r; 2676 rnd >>= 8; 2677 } 2678 return 0; 2679 } 2680 2681 /* send it */ 2682 2683 int 2684 sshpkt_send(struct ssh *ssh) 2685 { 2686 if (ssh->state && ssh->state->mux) 2687 return ssh_packet_send_mux(ssh); 2688 return ssh_packet_send2(ssh); 2689 } 2690 2691 int 2692 sshpkt_disconnect(struct ssh *ssh, const char *fmt,...) 2693 { 2694 char buf[1024]; 2695 va_list args; 2696 int r; 2697 2698 va_start(args, fmt); 2699 vsnprintf(buf, sizeof(buf), fmt, args); 2700 va_end(args); 2701 2702 if ((r = sshpkt_start(ssh, SSH2_MSG_DISCONNECT)) != 0 || 2703 (r = sshpkt_put_u32(ssh, SSH2_DISCONNECT_PROTOCOL_ERROR)) != 0 || 2704 (r = sshpkt_put_cstring(ssh, buf)) != 0 || 2705 (r = sshpkt_put_cstring(ssh, "")) != 0 || 2706 (r = sshpkt_send(ssh)) != 0) 2707 return r; 2708 return 0; 2709 } 2710 2711 /* roundup current message to pad bytes */ 2712 int 2713 sshpkt_add_padding(struct ssh *ssh, u_char pad) 2714 { 2715 ssh->state->extra_pad = pad; 2716 return 0; 2717 } 2718