1 /* $OpenBSD: packet.c,v 1.283 2019/03/01 03:29:32 djm Exp $ */ 2 /* 3 * Author: Tatu Ylonen <ylo@cs.hut.fi> 4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 5 * All rights reserved 6 * This file contains code implementing the packet protocol and communication 7 * with the other side. This same code is used both on client and server side. 8 * 9 * As far as I am concerned, the code I have written for this software 10 * can be used freely for any purpose. Any derived versions of this 11 * software must be clearly marked as such, and if the derived work is 12 * incompatible with the protocol description in the RFC file, it must be 13 * called by a name other than "ssh" or "Secure Shell". 14 * 15 * 16 * SSH2 packet format added by Markus Friedl. 17 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. 18 * 19 * Redistribution and use in source and binary forms, with or without 20 * modification, are permitted provided that the following conditions 21 * are met: 22 * 1. Redistributions of source code must retain the above copyright 23 * notice, this list of conditions and the following disclaimer. 24 * 2. Redistributions in binary form must reproduce the above copyright 25 * notice, this list of conditions and the following disclaimer in the 26 * documentation and/or other materials provided with the distribution. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 29 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 30 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 31 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 32 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 33 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 34 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 35 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 36 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 37 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 38 */ 39 40 #include "includes.h" 41 42 #include <sys/types.h> 43 #include "openbsd-compat/sys-queue.h" 44 #include <sys/socket.h> 45 #ifdef HAVE_SYS_TIME_H 46 # include <sys/time.h> 47 #endif 48 49 #include <netinet/in.h> 50 #include <netinet/ip.h> 51 #include <arpa/inet.h> 52 53 #include <errno.h> 54 #include <netdb.h> 55 #include <stdarg.h> 56 #include <stdio.h> 57 #include <stdlib.h> 58 #include <string.h> 59 #include <unistd.h> 60 #include <limits.h> 61 #include <poll.h> 62 #include <signal.h> 63 #include <time.h> 64 65 /* 66 * Explicitly include OpenSSL before zlib as some versions of OpenSSL have 67 * "free_func" in their headers, which zlib typedefs. 68 */ 69 #ifdef WITH_OPENSSL 70 # include <openssl/bn.h> 71 # include <openssl/evp.h> 72 # ifdef OPENSSL_HAS_ECC 73 # include <openssl/ec.h> 74 # endif 75 #endif 76 77 #include <zlib.h> 78 79 #include "xmalloc.h" 80 #include "crc32.h" 81 #include "compat.h" 82 #include "ssh2.h" 83 #include "cipher.h" 84 #include "sshkey.h" 85 #include "kex.h" 86 #include "digest.h" 87 #include "mac.h" 88 #include "log.h" 89 #include "canohost.h" 90 #include "misc.h" 91 #include "channels.h" 92 #include "ssh.h" 93 #include "packet.h" 94 #include "ssherr.h" 95 #include "sshbuf.h" 96 97 #ifdef PACKET_DEBUG 98 #define DBG(x) x 99 #else 100 #define DBG(x) 101 #endif 102 103 #define PACKET_MAX_SIZE (256 * 1024) 104 105 struct packet_state { 106 u_int32_t seqnr; 107 u_int32_t packets; 108 u_int64_t blocks; 109 u_int64_t bytes; 110 }; 111 112 struct packet { 113 TAILQ_ENTRY(packet) next; 114 u_char type; 115 struct sshbuf *payload; 116 }; 117 118 struct session_state { 119 /* 120 * This variable contains the file descriptors used for 121 * communicating with the other side. connection_in is used for 122 * reading; connection_out for writing. These can be the same 123 * descriptor, in which case it is assumed to be a socket. 124 */ 125 int connection_in; 126 int connection_out; 127 128 /* Protocol flags for the remote side. */ 129 u_int remote_protocol_flags; 130 131 /* Encryption context for receiving data. Only used for decryption. */ 132 struct sshcipher_ctx *receive_context; 133 134 /* Encryption context for sending data. Only used for encryption. */ 135 struct sshcipher_ctx *send_context; 136 137 /* Buffer for raw input data from the socket. */ 138 struct sshbuf *input; 139 140 /* Buffer for raw output data going to the socket. */ 141 struct sshbuf *output; 142 143 /* Buffer for the partial outgoing packet being constructed. */ 144 struct sshbuf *outgoing_packet; 145 146 /* Buffer for the incoming packet currently being processed. */ 147 struct sshbuf *incoming_packet; 148 149 /* Scratch buffer for packet compression/decompression. */ 150 struct sshbuf *compression_buffer; 151 152 /* Incoming/outgoing compression dictionaries */ 153 z_stream compression_in_stream; 154 z_stream compression_out_stream; 155 int compression_in_started; 156 int compression_out_started; 157 int compression_in_failures; 158 int compression_out_failures; 159 160 /* default maximum packet size */ 161 u_int max_packet_size; 162 163 /* Flag indicating whether this module has been initialized. */ 164 int initialized; 165 166 /* Set to true if the connection is interactive. */ 167 int interactive_mode; 168 169 /* Set to true if we are the server side. */ 170 int server_side; 171 172 /* Set to true if we are authenticated. */ 173 int after_authentication; 174 175 int keep_alive_timeouts; 176 177 /* The maximum time that we will wait to send or receive a packet */ 178 int packet_timeout_ms; 179 180 /* Session key information for Encryption and MAC */ 181 struct newkeys *newkeys[MODE_MAX]; 182 struct packet_state p_read, p_send; 183 184 /* Volume-based rekeying */ 185 u_int64_t max_blocks_in, max_blocks_out, rekey_limit; 186 187 /* Time-based rekeying */ 188 u_int32_t rekey_interval; /* how often in seconds */ 189 time_t rekey_time; /* time of last rekeying */ 190 191 /* roundup current message to extra_pad bytes */ 192 u_char extra_pad; 193 194 /* XXX discard incoming data after MAC error */ 195 u_int packet_discard; 196 size_t packet_discard_mac_already; 197 struct sshmac *packet_discard_mac; 198 199 /* Used in packet_read_poll2() */ 200 u_int packlen; 201 202 /* Used in packet_send2 */ 203 int rekeying; 204 205 /* Used in ssh_packet_send_mux() */ 206 int mux; 207 208 /* Used in packet_set_interactive */ 209 int set_interactive_called; 210 211 /* Used in packet_set_maxsize */ 212 int set_maxsize_called; 213 214 /* One-off warning about weak ciphers */ 215 int cipher_warning_done; 216 217 /* Hook for fuzzing inbound packets */ 218 ssh_packet_hook_fn *hook_in; 219 void *hook_in_ctx; 220 221 TAILQ_HEAD(, packet) outgoing; 222 }; 223 224 struct ssh * 225 ssh_alloc_session_state(void) 226 { 227 struct ssh *ssh = NULL; 228 struct session_state *state = NULL; 229 230 if ((ssh = calloc(1, sizeof(*ssh))) == NULL || 231 (state = calloc(1, sizeof(*state))) == NULL || 232 (ssh->kex = kex_new()) == NULL || 233 (state->input = sshbuf_new()) == NULL || 234 (state->output = sshbuf_new()) == NULL || 235 (state->outgoing_packet = sshbuf_new()) == NULL || 236 (state->incoming_packet = sshbuf_new()) == NULL) 237 goto fail; 238 TAILQ_INIT(&state->outgoing); 239 TAILQ_INIT(&ssh->private_keys); 240 TAILQ_INIT(&ssh->public_keys); 241 state->connection_in = -1; 242 state->connection_out = -1; 243 state->max_packet_size = 32768; 244 state->packet_timeout_ms = -1; 245 state->p_send.packets = state->p_read.packets = 0; 246 state->initialized = 1; 247 /* 248 * ssh_packet_send2() needs to queue packets until 249 * we've done the initial key exchange. 250 */ 251 state->rekeying = 1; 252 ssh->state = state; 253 return ssh; 254 fail: 255 if (ssh) { 256 kex_free(ssh->kex); 257 free(ssh); 258 } 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 return NULL; 267 } 268 269 void 270 ssh_packet_set_input_hook(struct ssh *ssh, ssh_packet_hook_fn *hook, void *ctx) 271 { 272 ssh->state->hook_in = hook; 273 ssh->state->hook_in_ctx = ctx; 274 } 275 276 /* Returns nonzero if rekeying is in progress */ 277 int 278 ssh_packet_is_rekeying(struct ssh *ssh) 279 { 280 return ssh->state->rekeying || ssh->kex->done == 0; 281 } 282 283 /* 284 * Sets the descriptors used for communication. 285 */ 286 struct ssh * 287 ssh_packet_set_connection(struct ssh *ssh, int fd_in, int fd_out) 288 { 289 struct session_state *state; 290 const struct sshcipher *none = cipher_by_name("none"); 291 int r; 292 293 if (none == NULL) { 294 error("%s: cannot load cipher 'none'", __func__); 295 return NULL; 296 } 297 if (ssh == NULL) 298 ssh = ssh_alloc_session_state(); 299 if (ssh == NULL) { 300 error("%s: cound not allocate state", __func__); 301 return NULL; 302 } 303 state = ssh->state; 304 state->connection_in = fd_in; 305 state->connection_out = fd_out; 306 if ((r = cipher_init(&state->send_context, none, 307 (const u_char *)"", 0, NULL, 0, CIPHER_ENCRYPT)) != 0 || 308 (r = cipher_init(&state->receive_context, none, 309 (const u_char *)"", 0, NULL, 0, CIPHER_DECRYPT)) != 0) { 310 error("%s: cipher_init failed: %s", __func__, ssh_err(r)); 311 free(ssh); /* XXX need ssh_free_session_state? */ 312 return NULL; 313 } 314 state->newkeys[MODE_IN] = state->newkeys[MODE_OUT] = NULL; 315 /* 316 * Cache the IP address of the remote connection for use in error 317 * messages that might be generated after the connection has closed. 318 */ 319 (void)ssh_remote_ipaddr(ssh); 320 return ssh; 321 } 322 323 void 324 ssh_packet_set_timeout(struct ssh *ssh, int timeout, int count) 325 { 326 struct session_state *state = ssh->state; 327 328 if (timeout <= 0 || count <= 0) { 329 state->packet_timeout_ms = -1; 330 return; 331 } 332 if ((INT_MAX / 1000) / count < timeout) 333 state->packet_timeout_ms = INT_MAX; 334 else 335 state->packet_timeout_ms = timeout * count * 1000; 336 } 337 338 void 339 ssh_packet_set_mux(struct ssh *ssh) 340 { 341 ssh->state->mux = 1; 342 ssh->state->rekeying = 0; 343 } 344 345 int 346 ssh_packet_get_mux(struct ssh *ssh) 347 { 348 return ssh->state->mux; 349 } 350 351 int 352 ssh_packet_set_log_preamble(struct ssh *ssh, const char *fmt, ...) 353 { 354 va_list args; 355 int r; 356 357 free(ssh->log_preamble); 358 if (fmt == NULL) 359 ssh->log_preamble = NULL; 360 else { 361 va_start(args, fmt); 362 r = vasprintf(&ssh->log_preamble, fmt, args); 363 va_end(args); 364 if (r < 0 || ssh->log_preamble == NULL) 365 return SSH_ERR_ALLOC_FAIL; 366 } 367 return 0; 368 } 369 370 int 371 ssh_packet_stop_discard(struct ssh *ssh) 372 { 373 struct session_state *state = ssh->state; 374 int r; 375 376 if (state->packet_discard_mac) { 377 char buf[1024]; 378 size_t dlen = PACKET_MAX_SIZE; 379 380 if (dlen > state->packet_discard_mac_already) 381 dlen -= state->packet_discard_mac_already; 382 memset(buf, 'a', sizeof(buf)); 383 while (sshbuf_len(state->incoming_packet) < dlen) 384 if ((r = sshbuf_put(state->incoming_packet, buf, 385 sizeof(buf))) != 0) 386 return r; 387 (void) mac_compute(state->packet_discard_mac, 388 state->p_read.seqnr, 389 sshbuf_ptr(state->incoming_packet), dlen, 390 NULL, 0); 391 } 392 logit("Finished discarding for %.200s port %d", 393 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 394 return SSH_ERR_MAC_INVALID; 395 } 396 397 static int 398 ssh_packet_start_discard(struct ssh *ssh, struct sshenc *enc, 399 struct sshmac *mac, size_t mac_already, u_int discard) 400 { 401 struct session_state *state = ssh->state; 402 int r; 403 404 if (enc == NULL || !cipher_is_cbc(enc->cipher) || (mac && mac->etm)) { 405 if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0) 406 return r; 407 return SSH_ERR_MAC_INVALID; 408 } 409 /* 410 * Record number of bytes over which the mac has already 411 * been computed in order to minimize timing attacks. 412 */ 413 if (mac && mac->enabled) { 414 state->packet_discard_mac = mac; 415 state->packet_discard_mac_already = mac_already; 416 } 417 if (sshbuf_len(state->input) >= discard) 418 return ssh_packet_stop_discard(ssh); 419 state->packet_discard = discard - sshbuf_len(state->input); 420 return 0; 421 } 422 423 /* Returns 1 if remote host is connected via socket, 0 if not. */ 424 425 int 426 ssh_packet_connection_is_on_socket(struct ssh *ssh) 427 { 428 struct session_state *state; 429 struct sockaddr_storage from, to; 430 socklen_t fromlen, tolen; 431 432 if (ssh == NULL || ssh->state == NULL) 433 return 0; 434 435 state = ssh->state; 436 if (state->connection_in == -1 || state->connection_out == -1) 437 return 0; 438 /* filedescriptors in and out are the same, so it's a socket */ 439 if (state->connection_in == state->connection_out) 440 return 1; 441 fromlen = sizeof(from); 442 memset(&from, 0, sizeof(from)); 443 if (getpeername(state->connection_in, (struct sockaddr *)&from, 444 &fromlen) < 0) 445 return 0; 446 tolen = sizeof(to); 447 memset(&to, 0, sizeof(to)); 448 if (getpeername(state->connection_out, (struct sockaddr *)&to, 449 &tolen) < 0) 450 return 0; 451 if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0) 452 return 0; 453 if (from.ss_family != AF_INET && from.ss_family != AF_INET6) 454 return 0; 455 return 1; 456 } 457 458 void 459 ssh_packet_get_bytes(struct ssh *ssh, u_int64_t *ibytes, u_int64_t *obytes) 460 { 461 if (ibytes) 462 *ibytes = ssh->state->p_read.bytes; 463 if (obytes) 464 *obytes = ssh->state->p_send.bytes; 465 } 466 467 int 468 ssh_packet_connection_af(struct ssh *ssh) 469 { 470 struct sockaddr_storage to; 471 socklen_t tolen = sizeof(to); 472 473 memset(&to, 0, sizeof(to)); 474 if (getsockname(ssh->state->connection_out, (struct sockaddr *)&to, 475 &tolen) < 0) 476 return 0; 477 #ifdef IPV4_IN_IPV6 478 if (to.ss_family == AF_INET6 && 479 IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)&to)->sin6_addr)) 480 return AF_INET; 481 #endif 482 return to.ss_family; 483 } 484 485 /* Sets the connection into non-blocking mode. */ 486 487 void 488 ssh_packet_set_nonblocking(struct ssh *ssh) 489 { 490 /* Set the socket into non-blocking mode. */ 491 set_nonblock(ssh->state->connection_in); 492 493 if (ssh->state->connection_out != ssh->state->connection_in) 494 set_nonblock(ssh->state->connection_out); 495 } 496 497 /* Returns the socket used for reading. */ 498 499 int 500 ssh_packet_get_connection_in(struct ssh *ssh) 501 { 502 return ssh->state->connection_in; 503 } 504 505 /* Returns the descriptor used for writing. */ 506 507 int 508 ssh_packet_get_connection_out(struct ssh *ssh) 509 { 510 return ssh->state->connection_out; 511 } 512 513 /* 514 * Returns the IP-address of the remote host as a string. The returned 515 * string must not be freed. 516 */ 517 518 const char * 519 ssh_remote_ipaddr(struct ssh *ssh) 520 { 521 int sock; 522 523 /* Check whether we have cached the ipaddr. */ 524 if (ssh->remote_ipaddr == NULL) { 525 if (ssh_packet_connection_is_on_socket(ssh)) { 526 sock = ssh->state->connection_in; 527 ssh->remote_ipaddr = get_peer_ipaddr(sock); 528 ssh->remote_port = get_peer_port(sock); 529 ssh->local_ipaddr = get_local_ipaddr(sock); 530 ssh->local_port = get_local_port(sock); 531 } else { 532 ssh->remote_ipaddr = strdup("UNKNOWN"); 533 ssh->remote_port = 65535; 534 ssh->local_ipaddr = strdup("UNKNOWN"); 535 ssh->local_port = 65535; 536 } 537 } 538 return ssh->remote_ipaddr; 539 } 540 541 /* Returns the port number of the remote host. */ 542 543 int 544 ssh_remote_port(struct ssh *ssh) 545 { 546 (void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */ 547 return ssh->remote_port; 548 } 549 550 /* 551 * Returns the IP-address of the local host as a string. The returned 552 * string must not be freed. 553 */ 554 555 const char * 556 ssh_local_ipaddr(struct ssh *ssh) 557 { 558 (void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */ 559 return ssh->local_ipaddr; 560 } 561 562 /* Returns the port number of the local host. */ 563 564 int 565 ssh_local_port(struct ssh *ssh) 566 { 567 (void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */ 568 return ssh->local_port; 569 } 570 571 /* Returns the routing domain of the input socket, or NULL if unavailable */ 572 const char * 573 ssh_packet_rdomain_in(struct ssh *ssh) 574 { 575 if (ssh->rdomain_in != NULL) 576 return ssh->rdomain_in; 577 if (!ssh_packet_connection_is_on_socket(ssh)) 578 return NULL; 579 ssh->rdomain_in = get_rdomain(ssh->state->connection_in); 580 return ssh->rdomain_in; 581 } 582 583 /* Closes the connection and clears and frees internal data structures. */ 584 585 static void 586 ssh_packet_close_internal(struct ssh *ssh, int do_close) 587 { 588 struct session_state *state = ssh->state; 589 u_int mode; 590 591 if (!state->initialized) 592 return; 593 state->initialized = 0; 594 if (do_close) { 595 if (state->connection_in == state->connection_out) { 596 close(state->connection_out); 597 } else { 598 close(state->connection_in); 599 close(state->connection_out); 600 } 601 } 602 sshbuf_free(state->input); 603 sshbuf_free(state->output); 604 sshbuf_free(state->outgoing_packet); 605 sshbuf_free(state->incoming_packet); 606 for (mode = 0; mode < MODE_MAX; mode++) { 607 kex_free_newkeys(state->newkeys[mode]); /* current keys */ 608 state->newkeys[mode] = NULL; 609 ssh_clear_newkeys(ssh, mode); /* next keys */ 610 } 611 /* compression state is in shared mem, so we can only release it once */ 612 if (do_close && state->compression_buffer) { 613 sshbuf_free(state->compression_buffer); 614 if (state->compression_out_started) { 615 z_streamp stream = &state->compression_out_stream; 616 debug("compress outgoing: " 617 "raw data %llu, compressed %llu, factor %.2f", 618 (unsigned long long)stream->total_in, 619 (unsigned long long)stream->total_out, 620 stream->total_in == 0 ? 0.0 : 621 (double) stream->total_out / stream->total_in); 622 if (state->compression_out_failures == 0) 623 deflateEnd(stream); 624 } 625 if (state->compression_in_started) { 626 z_streamp stream = &state->compression_in_stream; 627 debug("compress incoming: " 628 "raw data %llu, compressed %llu, factor %.2f", 629 (unsigned long long)stream->total_out, 630 (unsigned long long)stream->total_in, 631 stream->total_out == 0 ? 0.0 : 632 (double) stream->total_in / stream->total_out); 633 if (state->compression_in_failures == 0) 634 inflateEnd(stream); 635 } 636 } 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 } 648 } 649 650 void 651 ssh_packet_close(struct ssh *ssh) 652 { 653 ssh_packet_close_internal(ssh, 1); 654 } 655 656 void 657 ssh_packet_clear_keys(struct ssh *ssh) 658 { 659 ssh_packet_close_internal(ssh, 0); 660 } 661 662 /* Sets remote side protocol flags. */ 663 664 void 665 ssh_packet_set_protocol_flags(struct ssh *ssh, u_int protocol_flags) 666 { 667 ssh->state->remote_protocol_flags = protocol_flags; 668 } 669 670 /* Returns the remote protocol flags set earlier by the above function. */ 671 672 u_int 673 ssh_packet_get_protocol_flags(struct ssh *ssh) 674 { 675 return ssh->state->remote_protocol_flags; 676 } 677 678 /* 679 * Starts packet compression from the next packet on in both directions. 680 * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip. 681 */ 682 683 static int 684 ssh_packet_init_compression(struct ssh *ssh) 685 { 686 if (!ssh->state->compression_buffer && 687 ((ssh->state->compression_buffer = sshbuf_new()) == NULL)) 688 return SSH_ERR_ALLOC_FAIL; 689 return 0; 690 } 691 692 static int 693 start_compression_out(struct ssh *ssh, int level) 694 { 695 if (level < 1 || level > 9) 696 return SSH_ERR_INVALID_ARGUMENT; 697 debug("Enabling compression at level %d.", level); 698 if (ssh->state->compression_out_started == 1) 699 deflateEnd(&ssh->state->compression_out_stream); 700 switch (deflateInit(&ssh->state->compression_out_stream, level)) { 701 case Z_OK: 702 ssh->state->compression_out_started = 1; 703 break; 704 case Z_MEM_ERROR: 705 return SSH_ERR_ALLOC_FAIL; 706 default: 707 return SSH_ERR_INTERNAL_ERROR; 708 } 709 return 0; 710 } 711 712 static int 713 start_compression_in(struct ssh *ssh) 714 { 715 if (ssh->state->compression_in_started == 1) 716 inflateEnd(&ssh->state->compression_in_stream); 717 switch (inflateInit(&ssh->state->compression_in_stream)) { 718 case Z_OK: 719 ssh->state->compression_in_started = 1; 720 break; 721 case Z_MEM_ERROR: 722 return SSH_ERR_ALLOC_FAIL; 723 default: 724 return SSH_ERR_INTERNAL_ERROR; 725 } 726 return 0; 727 } 728 729 /* XXX remove need for separate compression buffer */ 730 static int 731 compress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out) 732 { 733 u_char buf[4096]; 734 int r, status; 735 736 if (ssh->state->compression_out_started != 1) 737 return SSH_ERR_INTERNAL_ERROR; 738 739 /* This case is not handled below. */ 740 if (sshbuf_len(in) == 0) 741 return 0; 742 743 /* Input is the contents of the input buffer. */ 744 if ((ssh->state->compression_out_stream.next_in = 745 sshbuf_mutable_ptr(in)) == NULL) 746 return SSH_ERR_INTERNAL_ERROR; 747 ssh->state->compression_out_stream.avail_in = sshbuf_len(in); 748 749 /* Loop compressing until deflate() returns with avail_out != 0. */ 750 do { 751 /* Set up fixed-size output buffer. */ 752 ssh->state->compression_out_stream.next_out = buf; 753 ssh->state->compression_out_stream.avail_out = sizeof(buf); 754 755 /* Compress as much data into the buffer as possible. */ 756 status = deflate(&ssh->state->compression_out_stream, 757 Z_PARTIAL_FLUSH); 758 switch (status) { 759 case Z_MEM_ERROR: 760 return SSH_ERR_ALLOC_FAIL; 761 case Z_OK: 762 /* Append compressed data to output_buffer. */ 763 if ((r = sshbuf_put(out, buf, sizeof(buf) - 764 ssh->state->compression_out_stream.avail_out)) != 0) 765 return r; 766 break; 767 case Z_STREAM_ERROR: 768 default: 769 ssh->state->compression_out_failures++; 770 return SSH_ERR_INVALID_FORMAT; 771 } 772 } while (ssh->state->compression_out_stream.avail_out == 0); 773 return 0; 774 } 775 776 static int 777 uncompress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out) 778 { 779 u_char buf[4096]; 780 int r, status; 781 782 if (ssh->state->compression_in_started != 1) 783 return SSH_ERR_INTERNAL_ERROR; 784 785 if ((ssh->state->compression_in_stream.next_in = 786 sshbuf_mutable_ptr(in)) == NULL) 787 return SSH_ERR_INTERNAL_ERROR; 788 ssh->state->compression_in_stream.avail_in = sshbuf_len(in); 789 790 for (;;) { 791 /* Set up fixed-size output buffer. */ 792 ssh->state->compression_in_stream.next_out = buf; 793 ssh->state->compression_in_stream.avail_out = sizeof(buf); 794 795 status = inflate(&ssh->state->compression_in_stream, 796 Z_PARTIAL_FLUSH); 797 switch (status) { 798 case Z_OK: 799 if ((r = sshbuf_put(out, buf, sizeof(buf) - 800 ssh->state->compression_in_stream.avail_out)) != 0) 801 return r; 802 break; 803 case Z_BUF_ERROR: 804 /* 805 * Comments in zlib.h say that we should keep calling 806 * inflate() until we get an error. This appears to 807 * be the error that we get. 808 */ 809 return 0; 810 case Z_DATA_ERROR: 811 return SSH_ERR_INVALID_FORMAT; 812 case Z_MEM_ERROR: 813 return SSH_ERR_ALLOC_FAIL; 814 case Z_STREAM_ERROR: 815 default: 816 ssh->state->compression_in_failures++; 817 return SSH_ERR_INTERNAL_ERROR; 818 } 819 } 820 /* NOTREACHED */ 821 } 822 823 void 824 ssh_clear_newkeys(struct ssh *ssh, int mode) 825 { 826 if (ssh->kex && ssh->kex->newkeys[mode]) { 827 kex_free_newkeys(ssh->kex->newkeys[mode]); 828 ssh->kex->newkeys[mode] = NULL; 829 } 830 } 831 832 int 833 ssh_set_newkeys(struct ssh *ssh, int mode) 834 { 835 struct session_state *state = ssh->state; 836 struct sshenc *enc; 837 struct sshmac *mac; 838 struct sshcomp *comp; 839 struct sshcipher_ctx **ccp; 840 struct packet_state *ps; 841 u_int64_t *max_blocks; 842 const char *wmsg; 843 int r, crypt_type; 844 const char *dir = mode == MODE_OUT ? "out" : "in"; 845 846 debug2("set_newkeys: mode %d", mode); 847 848 if (mode == MODE_OUT) { 849 ccp = &state->send_context; 850 crypt_type = CIPHER_ENCRYPT; 851 ps = &state->p_send; 852 max_blocks = &state->max_blocks_out; 853 } else { 854 ccp = &state->receive_context; 855 crypt_type = CIPHER_DECRYPT; 856 ps = &state->p_read; 857 max_blocks = &state->max_blocks_in; 858 } 859 if (state->newkeys[mode] != NULL) { 860 debug("%s: rekeying %s, input %llu bytes %llu blocks, " 861 "output %llu bytes %llu blocks", __func__, dir, 862 (unsigned long long)state->p_read.bytes, 863 (unsigned long long)state->p_read.blocks, 864 (unsigned long long)state->p_send.bytes, 865 (unsigned long long)state->p_send.blocks); 866 kex_free_newkeys(state->newkeys[mode]); 867 state->newkeys[mode] = NULL; 868 } 869 /* note that both bytes and the seqnr are not reset */ 870 ps->packets = ps->blocks = 0; 871 /* move newkeys from kex to state */ 872 if ((state->newkeys[mode] = ssh->kex->newkeys[mode]) == NULL) 873 return SSH_ERR_INTERNAL_ERROR; 874 ssh->kex->newkeys[mode] = NULL; 875 enc = &state->newkeys[mode]->enc; 876 mac = &state->newkeys[mode]->mac; 877 comp = &state->newkeys[mode]->comp; 878 if (cipher_authlen(enc->cipher) == 0) { 879 if ((r = mac_init(mac)) != 0) 880 return r; 881 } 882 mac->enabled = 1; 883 DBG(debug("%s: cipher_init_context: %s", __func__, dir)); 884 cipher_free(*ccp); 885 *ccp = NULL; 886 if ((r = cipher_init(ccp, enc->cipher, enc->key, enc->key_len, 887 enc->iv, enc->iv_len, crypt_type)) != 0) 888 return r; 889 if (!state->cipher_warning_done && 890 (wmsg = cipher_warning_message(*ccp)) != NULL) { 891 error("Warning: %s", wmsg); 892 state->cipher_warning_done = 1; 893 } 894 /* Deleting the keys does not gain extra security */ 895 /* explicit_bzero(enc->iv, enc->block_size); 896 explicit_bzero(enc->key, enc->key_len); 897 explicit_bzero(mac->key, mac->key_len); */ 898 if ((comp->type == COMP_ZLIB || 899 (comp->type == COMP_DELAYED && 900 state->after_authentication)) && comp->enabled == 0) { 901 if ((r = ssh_packet_init_compression(ssh)) < 0) 902 return r; 903 if (mode == MODE_OUT) { 904 if ((r = start_compression_out(ssh, 6)) != 0) 905 return r; 906 } else { 907 if ((r = start_compression_in(ssh)) != 0) 908 return r; 909 } 910 comp->enabled = 1; 911 } 912 /* 913 * The 2^(blocksize*2) limit is too expensive for 3DES, 914 * so enforce a 1GB limit for small blocksizes. 915 * See RFC4344 section 3.2. 916 */ 917 if (enc->block_size >= 16) 918 *max_blocks = (u_int64_t)1 << (enc->block_size*2); 919 else 920 *max_blocks = ((u_int64_t)1 << 30) / enc->block_size; 921 if (state->rekey_limit) 922 *max_blocks = MINIMUM(*max_blocks, 923 state->rekey_limit / enc->block_size); 924 debug("rekey %s after %llu blocks", dir, 925 (unsigned long long)*max_blocks); 926 return 0; 927 } 928 929 #define MAX_PACKETS (1U<<31) 930 static int 931 ssh_packet_need_rekeying(struct ssh *ssh, u_int outbound_packet_len) 932 { 933 struct session_state *state = ssh->state; 934 u_int32_t out_blocks; 935 936 /* XXX client can't cope with rekeying pre-auth */ 937 if (!state->after_authentication) 938 return 0; 939 940 /* Haven't keyed yet or KEX in progress. */ 941 if (ssh_packet_is_rekeying(ssh)) 942 return 0; 943 944 /* Peer can't rekey */ 945 if (ssh->compat & SSH_BUG_NOREKEY) 946 return 0; 947 948 /* 949 * Permit one packet in or out per rekey - this allows us to 950 * make progress when rekey limits are very small. 951 */ 952 if (state->p_send.packets == 0 && state->p_read.packets == 0) 953 return 0; 954 955 /* Time-based rekeying */ 956 if (state->rekey_interval != 0 && 957 (int64_t)state->rekey_time + state->rekey_interval <= monotime()) 958 return 1; 959 960 /* 961 * Always rekey when MAX_PACKETS sent in either direction 962 * As per RFC4344 section 3.1 we do this after 2^31 packets. 963 */ 964 if (state->p_send.packets > MAX_PACKETS || 965 state->p_read.packets > MAX_PACKETS) 966 return 1; 967 968 /* Rekey after (cipher-specific) maximum blocks */ 969 out_blocks = ROUNDUP(outbound_packet_len, 970 state->newkeys[MODE_OUT]->enc.block_size); 971 return (state->max_blocks_out && 972 (state->p_send.blocks + out_blocks > state->max_blocks_out)) || 973 (state->max_blocks_in && 974 (state->p_read.blocks > state->max_blocks_in)); 975 } 976 977 /* 978 * Delayed compression for SSH2 is enabled after authentication: 979 * This happens on the server side after a SSH2_MSG_USERAUTH_SUCCESS is sent, 980 * and on the client side after a SSH2_MSG_USERAUTH_SUCCESS is received. 981 */ 982 static int 983 ssh_packet_enable_delayed_compress(struct ssh *ssh) 984 { 985 struct session_state *state = ssh->state; 986 struct sshcomp *comp = NULL; 987 int r, mode; 988 989 /* 990 * Remember that we are past the authentication step, so rekeying 991 * with COMP_DELAYED will turn on compression immediately. 992 */ 993 state->after_authentication = 1; 994 for (mode = 0; mode < MODE_MAX; mode++) { 995 /* protocol error: USERAUTH_SUCCESS received before NEWKEYS */ 996 if (state->newkeys[mode] == NULL) 997 continue; 998 comp = &state->newkeys[mode]->comp; 999 if (comp && !comp->enabled && comp->type == COMP_DELAYED) { 1000 if ((r = ssh_packet_init_compression(ssh)) != 0) 1001 return r; 1002 if (mode == MODE_OUT) { 1003 if ((r = start_compression_out(ssh, 6)) != 0) 1004 return r; 1005 } else { 1006 if ((r = start_compression_in(ssh)) != 0) 1007 return r; 1008 } 1009 comp->enabled = 1; 1010 } 1011 } 1012 return 0; 1013 } 1014 1015 /* Used to mute debug logging for noisy packet types */ 1016 int 1017 ssh_packet_log_type(u_char type) 1018 { 1019 switch (type) { 1020 case SSH2_MSG_CHANNEL_DATA: 1021 case SSH2_MSG_CHANNEL_EXTENDED_DATA: 1022 case SSH2_MSG_CHANNEL_WINDOW_ADJUST: 1023 return 0; 1024 default: 1025 return 1; 1026 } 1027 } 1028 1029 /* 1030 * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue) 1031 */ 1032 int 1033 ssh_packet_send2_wrapped(struct ssh *ssh) 1034 { 1035 struct session_state *state = ssh->state; 1036 u_char type, *cp, macbuf[SSH_DIGEST_MAX_LENGTH]; 1037 u_char tmp, padlen, pad = 0; 1038 u_int authlen = 0, aadlen = 0; 1039 u_int len; 1040 struct sshenc *enc = NULL; 1041 struct sshmac *mac = NULL; 1042 struct sshcomp *comp = NULL; 1043 int r, block_size; 1044 1045 if (state->newkeys[MODE_OUT] != NULL) { 1046 enc = &state->newkeys[MODE_OUT]->enc; 1047 mac = &state->newkeys[MODE_OUT]->mac; 1048 comp = &state->newkeys[MODE_OUT]->comp; 1049 /* disable mac for authenticated encryption */ 1050 if ((authlen = cipher_authlen(enc->cipher)) != 0) 1051 mac = NULL; 1052 } 1053 block_size = enc ? enc->block_size : 8; 1054 aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0; 1055 1056 type = (sshbuf_ptr(state->outgoing_packet))[5]; 1057 if (ssh_packet_log_type(type)) 1058 debug3("send packet: type %u", type); 1059 #ifdef PACKET_DEBUG 1060 fprintf(stderr, "plain: "); 1061 sshbuf_dump(state->outgoing_packet, stderr); 1062 #endif 1063 1064 if (comp && comp->enabled) { 1065 len = sshbuf_len(state->outgoing_packet); 1066 /* skip header, compress only payload */ 1067 if ((r = sshbuf_consume(state->outgoing_packet, 5)) != 0) 1068 goto out; 1069 sshbuf_reset(state->compression_buffer); 1070 if ((r = compress_buffer(ssh, state->outgoing_packet, 1071 state->compression_buffer)) != 0) 1072 goto out; 1073 sshbuf_reset(state->outgoing_packet); 1074 if ((r = sshbuf_put(state->outgoing_packet, 1075 "\0\0\0\0\0", 5)) != 0 || 1076 (r = sshbuf_putb(state->outgoing_packet, 1077 state->compression_buffer)) != 0) 1078 goto out; 1079 DBG(debug("compression: raw %d compressed %zd", len, 1080 sshbuf_len(state->outgoing_packet))); 1081 } 1082 1083 /* sizeof (packet_len + pad_len + payload) */ 1084 len = sshbuf_len(state->outgoing_packet); 1085 1086 /* 1087 * calc size of padding, alloc space, get random data, 1088 * minimum padding is 4 bytes 1089 */ 1090 len -= aadlen; /* packet length is not encrypted for EtM modes */ 1091 padlen = block_size - (len % block_size); 1092 if (padlen < 4) 1093 padlen += block_size; 1094 if (state->extra_pad) { 1095 tmp = state->extra_pad; 1096 state->extra_pad = 1097 ROUNDUP(state->extra_pad, block_size); 1098 /* check if roundup overflowed */ 1099 if (state->extra_pad < tmp) 1100 return SSH_ERR_INVALID_ARGUMENT; 1101 tmp = (len + padlen) % state->extra_pad; 1102 /* Check whether pad calculation below will underflow */ 1103 if (tmp > state->extra_pad) 1104 return SSH_ERR_INVALID_ARGUMENT; 1105 pad = state->extra_pad - tmp; 1106 DBG(debug3("%s: adding %d (len %d padlen %d extra_pad %d)", 1107 __func__, pad, len, padlen, state->extra_pad)); 1108 tmp = padlen; 1109 padlen += pad; 1110 /* Check whether padlen calculation overflowed */ 1111 if (padlen < tmp) 1112 return SSH_ERR_INVALID_ARGUMENT; /* overflow */ 1113 state->extra_pad = 0; 1114 } 1115 if ((r = sshbuf_reserve(state->outgoing_packet, padlen, &cp)) != 0) 1116 goto out; 1117 if (enc && !cipher_ctx_is_plaintext(state->send_context)) { 1118 /* random padding */ 1119 arc4random_buf(cp, padlen); 1120 } else { 1121 /* clear padding */ 1122 explicit_bzero(cp, padlen); 1123 } 1124 /* sizeof (packet_len + pad_len + payload + padding) */ 1125 len = sshbuf_len(state->outgoing_packet); 1126 cp = sshbuf_mutable_ptr(state->outgoing_packet); 1127 if (cp == NULL) { 1128 r = SSH_ERR_INTERNAL_ERROR; 1129 goto out; 1130 } 1131 /* packet_length includes payload, padding and padding length field */ 1132 POKE_U32(cp, len - 4); 1133 cp[4] = padlen; 1134 DBG(debug("send: len %d (includes padlen %d, aadlen %d)", 1135 len, padlen, aadlen)); 1136 1137 /* compute MAC over seqnr and packet(length fields, payload, padding) */ 1138 if (mac && mac->enabled && !mac->etm) { 1139 if ((r = mac_compute(mac, state->p_send.seqnr, 1140 sshbuf_ptr(state->outgoing_packet), len, 1141 macbuf, sizeof(macbuf))) != 0) 1142 goto out; 1143 DBG(debug("done calc MAC out #%d", state->p_send.seqnr)); 1144 } 1145 /* encrypt packet and append to output buffer. */ 1146 if ((r = sshbuf_reserve(state->output, 1147 sshbuf_len(state->outgoing_packet) + authlen, &cp)) != 0) 1148 goto out; 1149 if ((r = cipher_crypt(state->send_context, state->p_send.seqnr, cp, 1150 sshbuf_ptr(state->outgoing_packet), 1151 len - aadlen, aadlen, authlen)) != 0) 1152 goto out; 1153 /* append unencrypted MAC */ 1154 if (mac && mac->enabled) { 1155 if (mac->etm) { 1156 /* EtM: compute mac over aadlen + cipher text */ 1157 if ((r = mac_compute(mac, state->p_send.seqnr, 1158 cp, len, macbuf, sizeof(macbuf))) != 0) 1159 goto out; 1160 DBG(debug("done calc MAC(EtM) out #%d", 1161 state->p_send.seqnr)); 1162 } 1163 if ((r = sshbuf_put(state->output, macbuf, mac->mac_len)) != 0) 1164 goto out; 1165 } 1166 #ifdef PACKET_DEBUG 1167 fprintf(stderr, "encrypted: "); 1168 sshbuf_dump(state->output, stderr); 1169 #endif 1170 /* increment sequence number for outgoing packets */ 1171 if (++state->p_send.seqnr == 0) 1172 logit("outgoing seqnr wraps around"); 1173 if (++state->p_send.packets == 0) 1174 if (!(ssh->compat & SSH_BUG_NOREKEY)) 1175 return SSH_ERR_NEED_REKEY; 1176 state->p_send.blocks += len / block_size; 1177 state->p_send.bytes += len; 1178 sshbuf_reset(state->outgoing_packet); 1179 1180 if (type == SSH2_MSG_NEWKEYS) 1181 r = ssh_set_newkeys(ssh, MODE_OUT); 1182 else if (type == SSH2_MSG_USERAUTH_SUCCESS && state->server_side) 1183 r = ssh_packet_enable_delayed_compress(ssh); 1184 else 1185 r = 0; 1186 out: 1187 return r; 1188 } 1189 1190 /* returns non-zero if the specified packet type is usec by KEX */ 1191 static int 1192 ssh_packet_type_is_kex(u_char type) 1193 { 1194 return 1195 type >= SSH2_MSG_TRANSPORT_MIN && 1196 type <= SSH2_MSG_TRANSPORT_MAX && 1197 type != SSH2_MSG_SERVICE_REQUEST && 1198 type != SSH2_MSG_SERVICE_ACCEPT && 1199 type != SSH2_MSG_EXT_INFO; 1200 } 1201 1202 int 1203 ssh_packet_send2(struct ssh *ssh) 1204 { 1205 struct session_state *state = ssh->state; 1206 struct packet *p; 1207 u_char type; 1208 int r, need_rekey; 1209 1210 if (sshbuf_len(state->outgoing_packet) < 6) 1211 return SSH_ERR_INTERNAL_ERROR; 1212 type = sshbuf_ptr(state->outgoing_packet)[5]; 1213 need_rekey = !ssh_packet_type_is_kex(type) && 1214 ssh_packet_need_rekeying(ssh, sshbuf_len(state->outgoing_packet)); 1215 1216 /* 1217 * During rekeying we can only send key exchange messages. 1218 * Queue everything else. 1219 */ 1220 if ((need_rekey || state->rekeying) && !ssh_packet_type_is_kex(type)) { 1221 if (need_rekey) 1222 debug3("%s: rekex triggered", __func__); 1223 debug("enqueue packet: %u", type); 1224 p = calloc(1, sizeof(*p)); 1225 if (p == NULL) 1226 return SSH_ERR_ALLOC_FAIL; 1227 p->type = type; 1228 p->payload = state->outgoing_packet; 1229 TAILQ_INSERT_TAIL(&state->outgoing, p, next); 1230 state->outgoing_packet = sshbuf_new(); 1231 if (state->outgoing_packet == NULL) 1232 return SSH_ERR_ALLOC_FAIL; 1233 if (need_rekey) { 1234 /* 1235 * This packet triggered a rekey, so send the 1236 * KEXINIT now. 1237 * NB. reenters this function via kex_start_rekex(). 1238 */ 1239 return kex_start_rekex(ssh); 1240 } 1241 return 0; 1242 } 1243 1244 /* rekeying starts with sending KEXINIT */ 1245 if (type == SSH2_MSG_KEXINIT) 1246 state->rekeying = 1; 1247 1248 if ((r = ssh_packet_send2_wrapped(ssh)) != 0) 1249 return r; 1250 1251 /* after a NEWKEYS message we can send the complete queue */ 1252 if (type == SSH2_MSG_NEWKEYS) { 1253 state->rekeying = 0; 1254 state->rekey_time = monotime(); 1255 while ((p = TAILQ_FIRST(&state->outgoing))) { 1256 type = p->type; 1257 /* 1258 * If this packet triggers a rekex, then skip the 1259 * remaining packets in the queue for now. 1260 * NB. re-enters this function via kex_start_rekex. 1261 */ 1262 if (ssh_packet_need_rekeying(ssh, 1263 sshbuf_len(p->payload))) { 1264 debug3("%s: queued packet triggered rekex", 1265 __func__); 1266 return kex_start_rekex(ssh); 1267 } 1268 debug("dequeue packet: %u", type); 1269 sshbuf_free(state->outgoing_packet); 1270 state->outgoing_packet = p->payload; 1271 TAILQ_REMOVE(&state->outgoing, p, next); 1272 memset(p, 0, sizeof(*p)); 1273 free(p); 1274 if ((r = ssh_packet_send2_wrapped(ssh)) != 0) 1275 return r; 1276 } 1277 } 1278 return 0; 1279 } 1280 1281 /* 1282 * Waits until a packet has been received, and returns its type. Note that 1283 * no other data is processed until this returns, so this function should not 1284 * be used during the interactive session. 1285 */ 1286 1287 int 1288 ssh_packet_read_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1289 { 1290 struct session_state *state = ssh->state; 1291 int len, r, ms_remain; 1292 fd_set *setp; 1293 char buf[8192]; 1294 struct timeval timeout, start, *timeoutp = NULL; 1295 1296 DBG(debug("packet_read()")); 1297 1298 setp = calloc(howmany(state->connection_in + 1, 1299 NFDBITS), sizeof(fd_mask)); 1300 if (setp == NULL) 1301 return SSH_ERR_ALLOC_FAIL; 1302 1303 /* 1304 * Since we are blocking, ensure that all written packets have 1305 * been sent. 1306 */ 1307 if ((r = ssh_packet_write_wait(ssh)) != 0) 1308 goto out; 1309 1310 /* Stay in the loop until we have received a complete packet. */ 1311 for (;;) { 1312 /* Try to read a packet from the buffer. */ 1313 r = ssh_packet_read_poll_seqnr(ssh, typep, seqnr_p); 1314 if (r != 0) 1315 break; 1316 /* If we got a packet, return it. */ 1317 if (*typep != SSH_MSG_NONE) 1318 break; 1319 /* 1320 * Otherwise, wait for some data to arrive, add it to the 1321 * buffer, and try again. 1322 */ 1323 memset(setp, 0, howmany(state->connection_in + 1, 1324 NFDBITS) * sizeof(fd_mask)); 1325 FD_SET(state->connection_in, setp); 1326 1327 if (state->packet_timeout_ms > 0) { 1328 ms_remain = state->packet_timeout_ms; 1329 timeoutp = &timeout; 1330 } 1331 /* Wait for some data to arrive. */ 1332 for (;;) { 1333 if (state->packet_timeout_ms != -1) { 1334 ms_to_timeval(&timeout, ms_remain); 1335 monotime_tv(&start); 1336 } 1337 if ((r = select(state->connection_in + 1, setp, 1338 NULL, NULL, timeoutp)) >= 0) 1339 break; 1340 if (errno != EAGAIN && errno != EINTR && 1341 errno != EWOULDBLOCK) { 1342 r = SSH_ERR_SYSTEM_ERROR; 1343 goto out; 1344 } 1345 if (state->packet_timeout_ms == -1) 1346 continue; 1347 ms_subtract_diff(&start, &ms_remain); 1348 if (ms_remain <= 0) { 1349 r = 0; 1350 break; 1351 } 1352 } 1353 if (r == 0) { 1354 r = SSH_ERR_CONN_TIMEOUT; 1355 goto out; 1356 } 1357 /* Read data from the socket. */ 1358 len = read(state->connection_in, buf, sizeof(buf)); 1359 if (len == 0) { 1360 r = SSH_ERR_CONN_CLOSED; 1361 goto out; 1362 } 1363 if (len < 0) { 1364 r = SSH_ERR_SYSTEM_ERROR; 1365 goto out; 1366 } 1367 1368 /* Append it to the buffer. */ 1369 if ((r = ssh_packet_process_incoming(ssh, buf, len)) != 0) 1370 goto out; 1371 } 1372 out: 1373 free(setp); 1374 return r; 1375 } 1376 1377 int 1378 ssh_packet_read(struct ssh *ssh) 1379 { 1380 u_char type; 1381 int r; 1382 1383 if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0) 1384 fatal("%s: %s", __func__, ssh_err(r)); 1385 return type; 1386 } 1387 1388 /* 1389 * Waits until a packet has been received, verifies that its type matches 1390 * that given, and gives a fatal error and exits if there is a mismatch. 1391 */ 1392 1393 int 1394 ssh_packet_read_expect(struct ssh *ssh, u_int expected_type) 1395 { 1396 int r; 1397 u_char type; 1398 1399 if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0) 1400 return r; 1401 if (type != expected_type) { 1402 if ((r = sshpkt_disconnect(ssh, 1403 "Protocol error: expected packet type %d, got %d", 1404 expected_type, type)) != 0) 1405 return r; 1406 return SSH_ERR_PROTOCOL_ERROR; 1407 } 1408 return 0; 1409 } 1410 1411 static int 1412 ssh_packet_read_poll2_mux(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1413 { 1414 struct session_state *state = ssh->state; 1415 const u_char *cp; 1416 size_t need; 1417 int r; 1418 1419 if (ssh->kex) 1420 return SSH_ERR_INTERNAL_ERROR; 1421 *typep = SSH_MSG_NONE; 1422 cp = sshbuf_ptr(state->input); 1423 if (state->packlen == 0) { 1424 if (sshbuf_len(state->input) < 4 + 1) 1425 return 0; /* packet is incomplete */ 1426 state->packlen = PEEK_U32(cp); 1427 if (state->packlen < 4 + 1 || 1428 state->packlen > PACKET_MAX_SIZE) 1429 return SSH_ERR_MESSAGE_INCOMPLETE; 1430 } 1431 need = state->packlen + 4; 1432 if (sshbuf_len(state->input) < need) 1433 return 0; /* packet is incomplete */ 1434 sshbuf_reset(state->incoming_packet); 1435 if ((r = sshbuf_put(state->incoming_packet, cp + 4, 1436 state->packlen)) != 0 || 1437 (r = sshbuf_consume(state->input, need)) != 0 || 1438 (r = sshbuf_get_u8(state->incoming_packet, NULL)) != 0 || 1439 (r = sshbuf_get_u8(state->incoming_packet, typep)) != 0) 1440 return r; 1441 if (ssh_packet_log_type(*typep)) 1442 debug3("%s: type %u", __func__, *typep); 1443 /* sshbuf_dump(state->incoming_packet, stderr); */ 1444 /* reset for next packet */ 1445 state->packlen = 0; 1446 return r; 1447 } 1448 1449 int 1450 ssh_packet_read_poll2(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1451 { 1452 struct session_state *state = ssh->state; 1453 u_int padlen, need; 1454 u_char *cp; 1455 u_int maclen, aadlen = 0, authlen = 0, block_size; 1456 struct sshenc *enc = NULL; 1457 struct sshmac *mac = NULL; 1458 struct sshcomp *comp = NULL; 1459 int r; 1460 1461 if (state->mux) 1462 return ssh_packet_read_poll2_mux(ssh, typep, seqnr_p); 1463 1464 *typep = SSH_MSG_NONE; 1465 1466 if (state->packet_discard) 1467 return 0; 1468 1469 if (state->newkeys[MODE_IN] != NULL) { 1470 enc = &state->newkeys[MODE_IN]->enc; 1471 mac = &state->newkeys[MODE_IN]->mac; 1472 comp = &state->newkeys[MODE_IN]->comp; 1473 /* disable mac for authenticated encryption */ 1474 if ((authlen = cipher_authlen(enc->cipher)) != 0) 1475 mac = NULL; 1476 } 1477 maclen = mac && mac->enabled ? mac->mac_len : 0; 1478 block_size = enc ? enc->block_size : 8; 1479 aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0; 1480 1481 if (aadlen && state->packlen == 0) { 1482 if (cipher_get_length(state->receive_context, 1483 &state->packlen, state->p_read.seqnr, 1484 sshbuf_ptr(state->input), sshbuf_len(state->input)) != 0) 1485 return 0; 1486 if (state->packlen < 1 + 4 || 1487 state->packlen > PACKET_MAX_SIZE) { 1488 #ifdef PACKET_DEBUG 1489 sshbuf_dump(state->input, stderr); 1490 #endif 1491 logit("Bad packet length %u.", state->packlen); 1492 if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0) 1493 return r; 1494 return SSH_ERR_CONN_CORRUPT; 1495 } 1496 sshbuf_reset(state->incoming_packet); 1497 } else if (state->packlen == 0) { 1498 /* 1499 * check if input size is less than the cipher block size, 1500 * decrypt first block and extract length of incoming packet 1501 */ 1502 if (sshbuf_len(state->input) < block_size) 1503 return 0; 1504 sshbuf_reset(state->incoming_packet); 1505 if ((r = sshbuf_reserve(state->incoming_packet, block_size, 1506 &cp)) != 0) 1507 goto out; 1508 if ((r = cipher_crypt(state->receive_context, 1509 state->p_send.seqnr, cp, sshbuf_ptr(state->input), 1510 block_size, 0, 0)) != 0) 1511 goto out; 1512 state->packlen = PEEK_U32(sshbuf_ptr(state->incoming_packet)); 1513 if (state->packlen < 1 + 4 || 1514 state->packlen > PACKET_MAX_SIZE) { 1515 #ifdef PACKET_DEBUG 1516 fprintf(stderr, "input: \n"); 1517 sshbuf_dump(state->input, stderr); 1518 fprintf(stderr, "incoming_packet: \n"); 1519 sshbuf_dump(state->incoming_packet, stderr); 1520 #endif 1521 logit("Bad packet length %u.", state->packlen); 1522 return ssh_packet_start_discard(ssh, enc, mac, 0, 1523 PACKET_MAX_SIZE); 1524 } 1525 if ((r = sshbuf_consume(state->input, block_size)) != 0) 1526 goto out; 1527 } 1528 DBG(debug("input: packet len %u", state->packlen+4)); 1529 1530 if (aadlen) { 1531 /* only the payload is encrypted */ 1532 need = state->packlen; 1533 } else { 1534 /* 1535 * the payload size and the payload are encrypted, but we 1536 * have a partial packet of block_size bytes 1537 */ 1538 need = 4 + state->packlen - block_size; 1539 } 1540 DBG(debug("partial packet: block %d, need %d, maclen %d, authlen %d," 1541 " aadlen %d", block_size, need, maclen, authlen, aadlen)); 1542 if (need % block_size != 0) { 1543 logit("padding error: need %d block %d mod %d", 1544 need, block_size, need % block_size); 1545 return ssh_packet_start_discard(ssh, enc, mac, 0, 1546 PACKET_MAX_SIZE - block_size); 1547 } 1548 /* 1549 * check if the entire packet has been received and 1550 * decrypt into incoming_packet: 1551 * 'aadlen' bytes are unencrypted, but authenticated. 1552 * 'need' bytes are encrypted, followed by either 1553 * 'authlen' bytes of authentication tag or 1554 * 'maclen' bytes of message authentication code. 1555 */ 1556 if (sshbuf_len(state->input) < aadlen + need + authlen + maclen) 1557 return 0; /* packet is incomplete */ 1558 #ifdef PACKET_DEBUG 1559 fprintf(stderr, "read_poll enc/full: "); 1560 sshbuf_dump(state->input, stderr); 1561 #endif 1562 /* EtM: check mac over encrypted input */ 1563 if (mac && mac->enabled && mac->etm) { 1564 if ((r = mac_check(mac, state->p_read.seqnr, 1565 sshbuf_ptr(state->input), aadlen + need, 1566 sshbuf_ptr(state->input) + aadlen + need + authlen, 1567 maclen)) != 0) { 1568 if (r == SSH_ERR_MAC_INVALID) 1569 logit("Corrupted MAC on input."); 1570 goto out; 1571 } 1572 } 1573 if ((r = sshbuf_reserve(state->incoming_packet, aadlen + need, 1574 &cp)) != 0) 1575 goto out; 1576 if ((r = cipher_crypt(state->receive_context, state->p_read.seqnr, cp, 1577 sshbuf_ptr(state->input), need, aadlen, authlen)) != 0) 1578 goto out; 1579 if ((r = sshbuf_consume(state->input, aadlen + need + authlen)) != 0) 1580 goto out; 1581 if (mac && mac->enabled) { 1582 /* Not EtM: check MAC over cleartext */ 1583 if (!mac->etm && (r = mac_check(mac, state->p_read.seqnr, 1584 sshbuf_ptr(state->incoming_packet), 1585 sshbuf_len(state->incoming_packet), 1586 sshbuf_ptr(state->input), maclen)) != 0) { 1587 if (r != SSH_ERR_MAC_INVALID) 1588 goto out; 1589 logit("Corrupted MAC on input."); 1590 if (need + block_size > PACKET_MAX_SIZE) 1591 return SSH_ERR_INTERNAL_ERROR; 1592 return ssh_packet_start_discard(ssh, enc, mac, 1593 sshbuf_len(state->incoming_packet), 1594 PACKET_MAX_SIZE - need - block_size); 1595 } 1596 /* Remove MAC from input buffer */ 1597 DBG(debug("MAC #%d ok", state->p_read.seqnr)); 1598 if ((r = sshbuf_consume(state->input, mac->mac_len)) != 0) 1599 goto out; 1600 } 1601 if (seqnr_p != NULL) 1602 *seqnr_p = state->p_read.seqnr; 1603 if (++state->p_read.seqnr == 0) 1604 logit("incoming seqnr wraps around"); 1605 if (++state->p_read.packets == 0) 1606 if (!(ssh->compat & SSH_BUG_NOREKEY)) 1607 return SSH_ERR_NEED_REKEY; 1608 state->p_read.blocks += (state->packlen + 4) / block_size; 1609 state->p_read.bytes += state->packlen + 4; 1610 1611 /* get padlen */ 1612 padlen = sshbuf_ptr(state->incoming_packet)[4]; 1613 DBG(debug("input: padlen %d", padlen)); 1614 if (padlen < 4) { 1615 if ((r = sshpkt_disconnect(ssh, 1616 "Corrupted padlen %d on input.", padlen)) != 0 || 1617 (r = ssh_packet_write_wait(ssh)) != 0) 1618 return r; 1619 return SSH_ERR_CONN_CORRUPT; 1620 } 1621 1622 /* skip packet size + padlen, discard padding */ 1623 if ((r = sshbuf_consume(state->incoming_packet, 4 + 1)) != 0 || 1624 ((r = sshbuf_consume_end(state->incoming_packet, padlen)) != 0)) 1625 goto out; 1626 1627 DBG(debug("input: len before de-compress %zd", 1628 sshbuf_len(state->incoming_packet))); 1629 if (comp && comp->enabled) { 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 DBG(debug("input: len after de-compress %zd", 1639 sshbuf_len(state->incoming_packet))); 1640 } 1641 /* 1642 * get packet type, implies consume. 1643 * return length of payload (without type field) 1644 */ 1645 if ((r = sshbuf_get_u8(state->incoming_packet, typep)) != 0) 1646 goto out; 1647 if (ssh_packet_log_type(*typep)) 1648 debug3("receive packet: type %u", *typep); 1649 if (*typep < SSH2_MSG_MIN || *typep >= SSH2_MSG_LOCAL_MIN) { 1650 if ((r = sshpkt_disconnect(ssh, 1651 "Invalid ssh2 packet type: %d", *typep)) != 0 || 1652 (r = ssh_packet_write_wait(ssh)) != 0) 1653 return r; 1654 return SSH_ERR_PROTOCOL_ERROR; 1655 } 1656 if (state->hook_in != NULL && 1657 (r = state->hook_in(ssh, state->incoming_packet, typep, 1658 state->hook_in_ctx)) != 0) 1659 return r; 1660 if (*typep == SSH2_MSG_USERAUTH_SUCCESS && !state->server_side) 1661 r = ssh_packet_enable_delayed_compress(ssh); 1662 else 1663 r = 0; 1664 #ifdef PACKET_DEBUG 1665 fprintf(stderr, "read/plain[%d]:\r\n", *typep); 1666 sshbuf_dump(state->incoming_packet, stderr); 1667 #endif 1668 /* reset for next packet */ 1669 state->packlen = 0; 1670 1671 /* do we need to rekey? */ 1672 if (ssh_packet_need_rekeying(ssh, 0)) { 1673 debug3("%s: rekex triggered", __func__); 1674 if ((r = kex_start_rekex(ssh)) != 0) 1675 return r; 1676 } 1677 out: 1678 return r; 1679 } 1680 1681 int 1682 ssh_packet_read_poll_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p) 1683 { 1684 struct session_state *state = ssh->state; 1685 u_int reason, seqnr; 1686 int r; 1687 u_char *msg; 1688 1689 for (;;) { 1690 msg = NULL; 1691 r = ssh_packet_read_poll2(ssh, typep, seqnr_p); 1692 if (r != 0) 1693 return r; 1694 if (*typep) { 1695 state->keep_alive_timeouts = 0; 1696 DBG(debug("received packet type %d", *typep)); 1697 } 1698 switch (*typep) { 1699 case SSH2_MSG_IGNORE: 1700 debug3("Received SSH2_MSG_IGNORE"); 1701 break; 1702 case SSH2_MSG_DEBUG: 1703 if ((r = sshpkt_get_u8(ssh, NULL)) != 0 || 1704 (r = sshpkt_get_string(ssh, &msg, NULL)) != 0 || 1705 (r = sshpkt_get_string(ssh, NULL, NULL)) != 0) { 1706 free(msg); 1707 return r; 1708 } 1709 debug("Remote: %.900s", msg); 1710 free(msg); 1711 break; 1712 case SSH2_MSG_DISCONNECT: 1713 if ((r = sshpkt_get_u32(ssh, &reason)) != 0 || 1714 (r = sshpkt_get_string(ssh, &msg, NULL)) != 0) 1715 return r; 1716 /* Ignore normal client exit notifications */ 1717 do_log2(ssh->state->server_side && 1718 reason == SSH2_DISCONNECT_BY_APPLICATION ? 1719 SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_ERROR, 1720 "Received disconnect from %s port %d:" 1721 "%u: %.400s", ssh_remote_ipaddr(ssh), 1722 ssh_remote_port(ssh), reason, msg); 1723 free(msg); 1724 return SSH_ERR_DISCONNECTED; 1725 case SSH2_MSG_UNIMPLEMENTED: 1726 if ((r = sshpkt_get_u32(ssh, &seqnr)) != 0) 1727 return r; 1728 debug("Received SSH2_MSG_UNIMPLEMENTED for %u", 1729 seqnr); 1730 break; 1731 default: 1732 return 0; 1733 } 1734 } 1735 } 1736 1737 /* 1738 * Buffers the given amount of input characters. This is intended to be used 1739 * together with packet_read_poll. 1740 */ 1741 1742 int 1743 ssh_packet_process_incoming(struct ssh *ssh, const char *buf, u_int len) 1744 { 1745 struct session_state *state = ssh->state; 1746 int r; 1747 1748 if (state->packet_discard) { 1749 state->keep_alive_timeouts = 0; /* ?? */ 1750 if (len >= state->packet_discard) { 1751 if ((r = ssh_packet_stop_discard(ssh)) != 0) 1752 return r; 1753 } 1754 state->packet_discard -= len; 1755 return 0; 1756 } 1757 if ((r = sshbuf_put(ssh->state->input, buf, len)) != 0) 1758 return r; 1759 1760 return 0; 1761 } 1762 1763 int 1764 ssh_packet_remaining(struct ssh *ssh) 1765 { 1766 return sshbuf_len(ssh->state->incoming_packet); 1767 } 1768 1769 /* 1770 * Sends a diagnostic message from the server to the client. This message 1771 * can be sent at any time (but not while constructing another message). The 1772 * message is printed immediately, but only if the client is being executed 1773 * in verbose mode. These messages are primarily intended to ease debugging 1774 * authentication problems. The length of the formatted message must not 1775 * exceed 1024 bytes. This will automatically call ssh_packet_write_wait. 1776 */ 1777 void 1778 ssh_packet_send_debug(struct ssh *ssh, const char *fmt,...) 1779 { 1780 char buf[1024]; 1781 va_list args; 1782 int r; 1783 1784 if ((ssh->compat & SSH_BUG_DEBUG)) 1785 return; 1786 1787 va_start(args, fmt); 1788 vsnprintf(buf, sizeof(buf), fmt, args); 1789 va_end(args); 1790 1791 debug3("sending debug message: %s", buf); 1792 1793 if ((r = sshpkt_start(ssh, SSH2_MSG_DEBUG)) != 0 || 1794 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* always display */ 1795 (r = sshpkt_put_cstring(ssh, buf)) != 0 || 1796 (r = sshpkt_put_cstring(ssh, "")) != 0 || 1797 (r = sshpkt_send(ssh)) != 0 || 1798 (r = ssh_packet_write_wait(ssh)) != 0) 1799 fatal("%s: %s", __func__, ssh_err(r)); 1800 } 1801 1802 void 1803 sshpkt_fmt_connection_id(struct ssh *ssh, char *s, size_t l) 1804 { 1805 snprintf(s, l, "%.200s%s%s port %d", 1806 ssh->log_preamble ? ssh->log_preamble : "", 1807 ssh->log_preamble ? " " : "", 1808 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 1809 } 1810 1811 /* 1812 * Pretty-print connection-terminating errors and exit. 1813 */ 1814 static void 1815 sshpkt_vfatal(struct ssh *ssh, int r, const char *fmt, va_list ap) 1816 { 1817 char *tag = NULL, remote_id[512]; 1818 1819 sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id)); 1820 1821 switch (r) { 1822 case SSH_ERR_CONN_CLOSED: 1823 ssh_packet_clear_keys(ssh); 1824 logdie("Connection closed by %s", remote_id); 1825 case SSH_ERR_CONN_TIMEOUT: 1826 ssh_packet_clear_keys(ssh); 1827 logdie("Connection %s %s timed out", 1828 ssh->state->server_side ? "from" : "to", remote_id); 1829 case SSH_ERR_DISCONNECTED: 1830 ssh_packet_clear_keys(ssh); 1831 logdie("Disconnected from %s", remote_id); 1832 case SSH_ERR_SYSTEM_ERROR: 1833 if (errno == ECONNRESET) { 1834 ssh_packet_clear_keys(ssh); 1835 logdie("Connection reset by %s", remote_id); 1836 } 1837 /* FALLTHROUGH */ 1838 case SSH_ERR_NO_CIPHER_ALG_MATCH: 1839 case SSH_ERR_NO_MAC_ALG_MATCH: 1840 case SSH_ERR_NO_COMPRESS_ALG_MATCH: 1841 case SSH_ERR_NO_KEX_ALG_MATCH: 1842 case SSH_ERR_NO_HOSTKEY_ALG_MATCH: 1843 if (ssh && ssh->kex && ssh->kex->failed_choice) { 1844 ssh_packet_clear_keys(ssh); 1845 logdie("Unable to negotiate with %s: %s. " 1846 "Their offer: %s", remote_id, ssh_err(r), 1847 ssh->kex->failed_choice); 1848 } 1849 /* FALLTHROUGH */ 1850 default: 1851 if (vasprintf(&tag, fmt, ap) == -1) { 1852 ssh_packet_clear_keys(ssh); 1853 logdie("%s: could not allocate failure message", 1854 __func__); 1855 } 1856 ssh_packet_clear_keys(ssh); 1857 logdie("%s%sConnection %s %s: %s", 1858 tag != NULL ? tag : "", tag != NULL ? ": " : "", 1859 ssh->state->server_side ? "from" : "to", 1860 remote_id, ssh_err(r)); 1861 } 1862 } 1863 1864 void 1865 sshpkt_fatal(struct ssh *ssh, int r, const char *fmt, ...) 1866 { 1867 va_list ap; 1868 1869 va_start(ap, fmt); 1870 sshpkt_vfatal(ssh, r, fmt, ap); 1871 /* NOTREACHED */ 1872 va_end(ap); 1873 logdie("%s: should have exited", __func__); 1874 } 1875 1876 /* 1877 * Logs the error plus constructs and sends a disconnect packet, closes the 1878 * connection, and exits. This function never returns. The error message 1879 * should not contain a newline. The length of the formatted message must 1880 * not exceed 1024 bytes. 1881 */ 1882 void 1883 ssh_packet_disconnect(struct ssh *ssh, const char *fmt,...) 1884 { 1885 char buf[1024], remote_id[512]; 1886 va_list args; 1887 static int disconnecting = 0; 1888 int r; 1889 1890 if (disconnecting) /* Guard against recursive invocations. */ 1891 fatal("packet_disconnect called recursively."); 1892 disconnecting = 1; 1893 1894 /* 1895 * Format the message. Note that the caller must make sure the 1896 * message is of limited size. 1897 */ 1898 sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id)); 1899 va_start(args, fmt); 1900 vsnprintf(buf, sizeof(buf), fmt, args); 1901 va_end(args); 1902 1903 /* Display the error locally */ 1904 logit("Disconnecting %s: %.100s", remote_id, buf); 1905 1906 /* 1907 * Send the disconnect message to the other side, and wait 1908 * for it to get sent. 1909 */ 1910 if ((r = sshpkt_disconnect(ssh, "%s", buf)) != 0) 1911 sshpkt_fatal(ssh, r, "%s", __func__); 1912 1913 if ((r = ssh_packet_write_wait(ssh)) != 0) 1914 sshpkt_fatal(ssh, r, "%s", __func__); 1915 1916 /* Close the connection. */ 1917 ssh_packet_close(ssh); 1918 cleanup_exit(255); 1919 } 1920 1921 /* 1922 * Checks if there is any buffered output, and tries to write some of 1923 * the output. 1924 */ 1925 int 1926 ssh_packet_write_poll(struct ssh *ssh) 1927 { 1928 struct session_state *state = ssh->state; 1929 int len = sshbuf_len(state->output); 1930 int r; 1931 1932 if (len > 0) { 1933 len = write(state->connection_out, 1934 sshbuf_ptr(state->output), len); 1935 if (len == -1) { 1936 if (errno == EINTR || errno == EAGAIN || 1937 errno == EWOULDBLOCK) 1938 return 0; 1939 return SSH_ERR_SYSTEM_ERROR; 1940 } 1941 if (len == 0) 1942 return SSH_ERR_CONN_CLOSED; 1943 if ((r = sshbuf_consume(state->output, len)) != 0) 1944 return r; 1945 } 1946 return 0; 1947 } 1948 1949 /* 1950 * Calls packet_write_poll repeatedly until all pending output data has been 1951 * written. 1952 */ 1953 int 1954 ssh_packet_write_wait(struct ssh *ssh) 1955 { 1956 fd_set *setp; 1957 int ret, r, ms_remain = 0; 1958 struct timeval start, timeout, *timeoutp = NULL; 1959 struct session_state *state = ssh->state; 1960 1961 setp = calloc(howmany(state->connection_out + 1, 1962 NFDBITS), sizeof(fd_mask)); 1963 if (setp == NULL) 1964 return SSH_ERR_ALLOC_FAIL; 1965 if ((r = ssh_packet_write_poll(ssh)) != 0) { 1966 free(setp); 1967 return r; 1968 } 1969 while (ssh_packet_have_data_to_write(ssh)) { 1970 memset(setp, 0, howmany(state->connection_out + 1, 1971 NFDBITS) * sizeof(fd_mask)); 1972 FD_SET(state->connection_out, setp); 1973 1974 if (state->packet_timeout_ms > 0) { 1975 ms_remain = state->packet_timeout_ms; 1976 timeoutp = &timeout; 1977 } 1978 for (;;) { 1979 if (state->packet_timeout_ms != -1) { 1980 ms_to_timeval(&timeout, ms_remain); 1981 monotime_tv(&start); 1982 } 1983 if ((ret = select(state->connection_out + 1, 1984 NULL, setp, NULL, timeoutp)) >= 0) 1985 break; 1986 if (errno != EAGAIN && errno != EINTR && 1987 errno != EWOULDBLOCK) 1988 break; 1989 if (state->packet_timeout_ms == -1) 1990 continue; 1991 ms_subtract_diff(&start, &ms_remain); 1992 if (ms_remain <= 0) { 1993 ret = 0; 1994 break; 1995 } 1996 } 1997 if (ret == 0) { 1998 free(setp); 1999 return SSH_ERR_CONN_TIMEOUT; 2000 } 2001 if ((r = ssh_packet_write_poll(ssh)) != 0) { 2002 free(setp); 2003 return r; 2004 } 2005 } 2006 free(setp); 2007 return 0; 2008 } 2009 2010 /* Returns true if there is buffered data to write to the connection. */ 2011 2012 int 2013 ssh_packet_have_data_to_write(struct ssh *ssh) 2014 { 2015 return sshbuf_len(ssh->state->output) != 0; 2016 } 2017 2018 /* Returns true if there is not too much data to write to the connection. */ 2019 2020 int 2021 ssh_packet_not_very_much_data_to_write(struct ssh *ssh) 2022 { 2023 if (ssh->state->interactive_mode) 2024 return sshbuf_len(ssh->state->output) < 16384; 2025 else 2026 return sshbuf_len(ssh->state->output) < 128 * 1024; 2027 } 2028 2029 void 2030 ssh_packet_set_tos(struct ssh *ssh, int tos) 2031 { 2032 #ifndef IP_TOS_IS_BROKEN 2033 if (!ssh_packet_connection_is_on_socket(ssh) || tos == INT_MAX) 2034 return; 2035 switch (ssh_packet_connection_af(ssh)) { 2036 # ifdef IP_TOS 2037 case AF_INET: 2038 debug3("%s: set IP_TOS 0x%02x", __func__, tos); 2039 if (setsockopt(ssh->state->connection_in, 2040 IPPROTO_IP, IP_TOS, &tos, sizeof(tos)) < 0) 2041 error("setsockopt IP_TOS %d: %.100s:", 2042 tos, strerror(errno)); 2043 break; 2044 # endif /* IP_TOS */ 2045 # ifdef IPV6_TCLASS 2046 case AF_INET6: 2047 debug3("%s: set IPV6_TCLASS 0x%02x", __func__, tos); 2048 if (setsockopt(ssh->state->connection_in, 2049 IPPROTO_IPV6, IPV6_TCLASS, &tos, sizeof(tos)) < 0) 2050 error("setsockopt IPV6_TCLASS %d: %.100s:", 2051 tos, strerror(errno)); 2052 break; 2053 # endif /* IPV6_TCLASS */ 2054 } 2055 #endif /* IP_TOS_IS_BROKEN */ 2056 } 2057 2058 /* Informs that the current session is interactive. Sets IP flags for that. */ 2059 2060 void 2061 ssh_packet_set_interactive(struct ssh *ssh, int interactive, int qos_interactive, int qos_bulk) 2062 { 2063 struct session_state *state = ssh->state; 2064 2065 if (state->set_interactive_called) 2066 return; 2067 state->set_interactive_called = 1; 2068 2069 /* Record that we are in interactive mode. */ 2070 state->interactive_mode = interactive; 2071 2072 /* Only set socket options if using a socket. */ 2073 if (!ssh_packet_connection_is_on_socket(ssh)) 2074 return; 2075 set_nodelay(state->connection_in); 2076 ssh_packet_set_tos(ssh, interactive ? qos_interactive : 2077 qos_bulk); 2078 } 2079 2080 /* Returns true if the current connection is interactive. */ 2081 2082 int 2083 ssh_packet_is_interactive(struct ssh *ssh) 2084 { 2085 return ssh->state->interactive_mode; 2086 } 2087 2088 int 2089 ssh_packet_set_maxsize(struct ssh *ssh, u_int s) 2090 { 2091 struct session_state *state = ssh->state; 2092 2093 if (state->set_maxsize_called) { 2094 logit("packet_set_maxsize: called twice: old %d new %d", 2095 state->max_packet_size, s); 2096 return -1; 2097 } 2098 if (s < 4 * 1024 || s > 1024 * 1024) { 2099 logit("packet_set_maxsize: bad size %d", s); 2100 return -1; 2101 } 2102 state->set_maxsize_called = 1; 2103 debug("packet_set_maxsize: setting to %d", s); 2104 state->max_packet_size = s; 2105 return s; 2106 } 2107 2108 int 2109 ssh_packet_inc_alive_timeouts(struct ssh *ssh) 2110 { 2111 return ++ssh->state->keep_alive_timeouts; 2112 } 2113 2114 void 2115 ssh_packet_set_alive_timeouts(struct ssh *ssh, int ka) 2116 { 2117 ssh->state->keep_alive_timeouts = ka; 2118 } 2119 2120 u_int 2121 ssh_packet_get_maxsize(struct ssh *ssh) 2122 { 2123 return ssh->state->max_packet_size; 2124 } 2125 2126 void 2127 ssh_packet_set_rekey_limits(struct ssh *ssh, u_int64_t bytes, u_int32_t seconds) 2128 { 2129 debug3("rekey after %llu bytes, %u seconds", (unsigned long long)bytes, 2130 (unsigned int)seconds); 2131 ssh->state->rekey_limit = bytes; 2132 ssh->state->rekey_interval = seconds; 2133 } 2134 2135 time_t 2136 ssh_packet_get_rekey_timeout(struct ssh *ssh) 2137 { 2138 time_t seconds; 2139 2140 seconds = ssh->state->rekey_time + ssh->state->rekey_interval - 2141 monotime(); 2142 return (seconds <= 0 ? 1 : seconds); 2143 } 2144 2145 void 2146 ssh_packet_set_server(struct ssh *ssh) 2147 { 2148 ssh->state->server_side = 1; 2149 ssh->kex->server = 1; /* XXX unify? */ 2150 } 2151 2152 void 2153 ssh_packet_set_authenticated(struct ssh *ssh) 2154 { 2155 ssh->state->after_authentication = 1; 2156 } 2157 2158 void * 2159 ssh_packet_get_input(struct ssh *ssh) 2160 { 2161 return (void *)ssh->state->input; 2162 } 2163 2164 void * 2165 ssh_packet_get_output(struct ssh *ssh) 2166 { 2167 return (void *)ssh->state->output; 2168 } 2169 2170 /* Reset after_authentication and reset compression in post-auth privsep */ 2171 static int 2172 ssh_packet_set_postauth(struct ssh *ssh) 2173 { 2174 int r; 2175 2176 debug("%s: called", __func__); 2177 /* This was set in net child, but is not visible in user child */ 2178 ssh->state->after_authentication = 1; 2179 ssh->state->rekeying = 0; 2180 if ((r = ssh_packet_enable_delayed_compress(ssh)) != 0) 2181 return r; 2182 return 0; 2183 } 2184 2185 /* Packet state (de-)serialization for privsep */ 2186 2187 /* turn kex into a blob for packet state serialization */ 2188 static int 2189 kex_to_blob(struct sshbuf *m, struct kex *kex) 2190 { 2191 int r; 2192 2193 if ((r = sshbuf_put_string(m, kex->session_id, 2194 kex->session_id_len)) != 0 || 2195 (r = sshbuf_put_u32(m, kex->we_need)) != 0 || 2196 (r = sshbuf_put_cstring(m, kex->hostkey_alg)) != 0 || 2197 (r = sshbuf_put_u32(m, kex->hostkey_type)) != 0 || 2198 (r = sshbuf_put_u32(m, kex->hostkey_nid)) != 0 || 2199 (r = sshbuf_put_u32(m, kex->kex_type)) != 0 || 2200 (r = sshbuf_put_stringb(m, kex->my)) != 0 || 2201 (r = sshbuf_put_stringb(m, kex->peer)) != 0 || 2202 (r = sshbuf_put_stringb(m, kex->client_version)) != 0 || 2203 (r = sshbuf_put_stringb(m, kex->server_version)) != 0 || 2204 (r = sshbuf_put_u32(m, kex->flags)) != 0) 2205 return r; 2206 return 0; 2207 } 2208 2209 /* turn key exchange results into a blob for packet state serialization */ 2210 static int 2211 newkeys_to_blob(struct sshbuf *m, struct ssh *ssh, int mode) 2212 { 2213 struct sshbuf *b; 2214 struct sshcipher_ctx *cc; 2215 struct sshcomp *comp; 2216 struct sshenc *enc; 2217 struct sshmac *mac; 2218 struct newkeys *newkey; 2219 int r; 2220 2221 if ((newkey = ssh->state->newkeys[mode]) == NULL) 2222 return SSH_ERR_INTERNAL_ERROR; 2223 enc = &newkey->enc; 2224 mac = &newkey->mac; 2225 comp = &newkey->comp; 2226 cc = (mode == MODE_OUT) ? ssh->state->send_context : 2227 ssh->state->receive_context; 2228 if ((r = cipher_get_keyiv(cc, enc->iv, enc->iv_len)) != 0) 2229 return r; 2230 if ((b = sshbuf_new()) == NULL) 2231 return SSH_ERR_ALLOC_FAIL; 2232 if ((r = sshbuf_put_cstring(b, enc->name)) != 0 || 2233 (r = sshbuf_put_u32(b, enc->enabled)) != 0 || 2234 (r = sshbuf_put_u32(b, enc->block_size)) != 0 || 2235 (r = sshbuf_put_string(b, enc->key, enc->key_len)) != 0 || 2236 (r = sshbuf_put_string(b, enc->iv, enc->iv_len)) != 0) 2237 goto out; 2238 if (cipher_authlen(enc->cipher) == 0) { 2239 if ((r = sshbuf_put_cstring(b, mac->name)) != 0 || 2240 (r = sshbuf_put_u32(b, mac->enabled)) != 0 || 2241 (r = sshbuf_put_string(b, mac->key, mac->key_len)) != 0) 2242 goto out; 2243 } 2244 if ((r = sshbuf_put_u32(b, comp->type)) != 0 || 2245 (r = sshbuf_put_cstring(b, comp->name)) != 0) 2246 goto out; 2247 r = sshbuf_put_stringb(m, b); 2248 out: 2249 sshbuf_free(b); 2250 return r; 2251 } 2252 2253 /* serialize packet state into a blob */ 2254 int 2255 ssh_packet_get_state(struct ssh *ssh, struct sshbuf *m) 2256 { 2257 struct session_state *state = ssh->state; 2258 int r; 2259 2260 if ((r = kex_to_blob(m, ssh->kex)) != 0 || 2261 (r = newkeys_to_blob(m, ssh, MODE_OUT)) != 0 || 2262 (r = newkeys_to_blob(m, ssh, MODE_IN)) != 0 || 2263 (r = sshbuf_put_u64(m, state->rekey_limit)) != 0 || 2264 (r = sshbuf_put_u32(m, state->rekey_interval)) != 0 || 2265 (r = sshbuf_put_u32(m, state->p_send.seqnr)) != 0 || 2266 (r = sshbuf_put_u64(m, state->p_send.blocks)) != 0 || 2267 (r = sshbuf_put_u32(m, state->p_send.packets)) != 0 || 2268 (r = sshbuf_put_u64(m, state->p_send.bytes)) != 0 || 2269 (r = sshbuf_put_u32(m, state->p_read.seqnr)) != 0 || 2270 (r = sshbuf_put_u64(m, state->p_read.blocks)) != 0 || 2271 (r = sshbuf_put_u32(m, state->p_read.packets)) != 0 || 2272 (r = sshbuf_put_u64(m, state->p_read.bytes)) != 0 || 2273 (r = sshbuf_put_stringb(m, state->input)) != 0 || 2274 (r = sshbuf_put_stringb(m, state->output)) != 0) 2275 return r; 2276 2277 return 0; 2278 } 2279 2280 /* restore key exchange results from blob for packet state de-serialization */ 2281 static int 2282 newkeys_from_blob(struct sshbuf *m, struct ssh *ssh, int mode) 2283 { 2284 struct sshbuf *b = NULL; 2285 struct sshcomp *comp; 2286 struct sshenc *enc; 2287 struct sshmac *mac; 2288 struct newkeys *newkey = NULL; 2289 size_t keylen, ivlen, maclen; 2290 int r; 2291 2292 if ((newkey = calloc(1, sizeof(*newkey))) == NULL) { 2293 r = SSH_ERR_ALLOC_FAIL; 2294 goto out; 2295 } 2296 if ((r = sshbuf_froms(m, &b)) != 0) 2297 goto out; 2298 #ifdef DEBUG_PK 2299 sshbuf_dump(b, stderr); 2300 #endif 2301 enc = &newkey->enc; 2302 mac = &newkey->mac; 2303 comp = &newkey->comp; 2304 2305 if ((r = sshbuf_get_cstring(b, &enc->name, NULL)) != 0 || 2306 (r = sshbuf_get_u32(b, (u_int *)&enc->enabled)) != 0 || 2307 (r = sshbuf_get_u32(b, &enc->block_size)) != 0 || 2308 (r = sshbuf_get_string(b, &enc->key, &keylen)) != 0 || 2309 (r = sshbuf_get_string(b, &enc->iv, &ivlen)) != 0) 2310 goto out; 2311 if ((enc->cipher = cipher_by_name(enc->name)) == NULL) { 2312 r = SSH_ERR_INVALID_FORMAT; 2313 goto out; 2314 } 2315 if (cipher_authlen(enc->cipher) == 0) { 2316 if ((r = sshbuf_get_cstring(b, &mac->name, NULL)) != 0) 2317 goto out; 2318 if ((r = mac_setup(mac, mac->name)) != 0) 2319 goto out; 2320 if ((r = sshbuf_get_u32(b, (u_int *)&mac->enabled)) != 0 || 2321 (r = sshbuf_get_string(b, &mac->key, &maclen)) != 0) 2322 goto out; 2323 if (maclen > mac->key_len) { 2324 r = SSH_ERR_INVALID_FORMAT; 2325 goto out; 2326 } 2327 mac->key_len = maclen; 2328 } 2329 if ((r = sshbuf_get_u32(b, &comp->type)) != 0 || 2330 (r = sshbuf_get_cstring(b, &comp->name, NULL)) != 0) 2331 goto out; 2332 if (sshbuf_len(b) != 0) { 2333 r = SSH_ERR_INVALID_FORMAT; 2334 goto out; 2335 } 2336 enc->key_len = keylen; 2337 enc->iv_len = ivlen; 2338 ssh->kex->newkeys[mode] = newkey; 2339 newkey = NULL; 2340 r = 0; 2341 out: 2342 free(newkey); 2343 sshbuf_free(b); 2344 return r; 2345 } 2346 2347 /* restore kex from blob for packet state de-serialization */ 2348 static int 2349 kex_from_blob(struct sshbuf *m, struct kex **kexp) 2350 { 2351 struct kex *kex; 2352 int r; 2353 2354 if ((kex = kex_new()) == NULL) 2355 return SSH_ERR_ALLOC_FAIL; 2356 if ((r = sshbuf_get_string(m, &kex->session_id, &kex->session_id_len)) != 0 || 2357 (r = sshbuf_get_u32(m, &kex->we_need)) != 0 || 2358 (r = sshbuf_get_cstring(m, &kex->hostkey_alg, NULL)) != 0 || 2359 (r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_type)) != 0 || 2360 (r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_nid)) != 0 || 2361 (r = sshbuf_get_u32(m, &kex->kex_type)) != 0 || 2362 (r = sshbuf_get_stringb(m, kex->my)) != 0 || 2363 (r = sshbuf_get_stringb(m, kex->peer)) != 0 || 2364 (r = sshbuf_get_stringb(m, kex->client_version)) != 0 || 2365 (r = sshbuf_get_stringb(m, kex->server_version)) != 0 || 2366 (r = sshbuf_get_u32(m, &kex->flags)) != 0) 2367 goto out; 2368 kex->server = 1; 2369 kex->done = 1; 2370 r = 0; 2371 out: 2372 if (r != 0 || kexp == NULL) { 2373 kex_free(kex); 2374 if (kexp != NULL) 2375 *kexp = NULL; 2376 } else { 2377 kex_free(*kexp); 2378 *kexp = kex; 2379 } 2380 return r; 2381 } 2382 2383 /* 2384 * Restore packet state from content of blob 'm' (de-serialization). 2385 * Note that 'm' will be partially consumed on parsing or any other errors. 2386 */ 2387 int 2388 ssh_packet_set_state(struct ssh *ssh, struct sshbuf *m) 2389 { 2390 struct session_state *state = ssh->state; 2391 const u_char *input, *output; 2392 size_t ilen, olen; 2393 int r; 2394 2395 if ((r = kex_from_blob(m, &ssh->kex)) != 0 || 2396 (r = newkeys_from_blob(m, ssh, MODE_OUT)) != 0 || 2397 (r = newkeys_from_blob(m, ssh, MODE_IN)) != 0 || 2398 (r = sshbuf_get_u64(m, &state->rekey_limit)) != 0 || 2399 (r = sshbuf_get_u32(m, &state->rekey_interval)) != 0 || 2400 (r = sshbuf_get_u32(m, &state->p_send.seqnr)) != 0 || 2401 (r = sshbuf_get_u64(m, &state->p_send.blocks)) != 0 || 2402 (r = sshbuf_get_u32(m, &state->p_send.packets)) != 0 || 2403 (r = sshbuf_get_u64(m, &state->p_send.bytes)) != 0 || 2404 (r = sshbuf_get_u32(m, &state->p_read.seqnr)) != 0 || 2405 (r = sshbuf_get_u64(m, &state->p_read.blocks)) != 0 || 2406 (r = sshbuf_get_u32(m, &state->p_read.packets)) != 0 || 2407 (r = sshbuf_get_u64(m, &state->p_read.bytes)) != 0) 2408 return r; 2409 /* 2410 * We set the time here so that in post-auth privsep slave we 2411 * count from the completion of the authentication. 2412 */ 2413 state->rekey_time = monotime(); 2414 /* XXX ssh_set_newkeys overrides p_read.packets? XXX */ 2415 if ((r = ssh_set_newkeys(ssh, MODE_IN)) != 0 || 2416 (r = ssh_set_newkeys(ssh, MODE_OUT)) != 0) 2417 return r; 2418 2419 if ((r = ssh_packet_set_postauth(ssh)) != 0) 2420 return r; 2421 2422 sshbuf_reset(state->input); 2423 sshbuf_reset(state->output); 2424 if ((r = sshbuf_get_string_direct(m, &input, &ilen)) != 0 || 2425 (r = sshbuf_get_string_direct(m, &output, &olen)) != 0 || 2426 (r = sshbuf_put(state->input, input, ilen)) != 0 || 2427 (r = sshbuf_put(state->output, output, olen)) != 0) 2428 return r; 2429 2430 if (sshbuf_len(m)) 2431 return SSH_ERR_INVALID_FORMAT; 2432 debug3("%s: done", __func__); 2433 return 0; 2434 } 2435 2436 /* NEW API */ 2437 2438 /* put data to the outgoing packet */ 2439 2440 int 2441 sshpkt_put(struct ssh *ssh, const void *v, size_t len) 2442 { 2443 return sshbuf_put(ssh->state->outgoing_packet, v, len); 2444 } 2445 2446 int 2447 sshpkt_putb(struct ssh *ssh, const struct sshbuf *b) 2448 { 2449 return sshbuf_putb(ssh->state->outgoing_packet, b); 2450 } 2451 2452 int 2453 sshpkt_put_u8(struct ssh *ssh, u_char val) 2454 { 2455 return sshbuf_put_u8(ssh->state->outgoing_packet, val); 2456 } 2457 2458 int 2459 sshpkt_put_u32(struct ssh *ssh, u_int32_t val) 2460 { 2461 return sshbuf_put_u32(ssh->state->outgoing_packet, val); 2462 } 2463 2464 int 2465 sshpkt_put_u64(struct ssh *ssh, u_int64_t val) 2466 { 2467 return sshbuf_put_u64(ssh->state->outgoing_packet, val); 2468 } 2469 2470 int 2471 sshpkt_put_string(struct ssh *ssh, const void *v, size_t len) 2472 { 2473 return sshbuf_put_string(ssh->state->outgoing_packet, v, len); 2474 } 2475 2476 int 2477 sshpkt_put_cstring(struct ssh *ssh, const void *v) 2478 { 2479 return sshbuf_put_cstring(ssh->state->outgoing_packet, v); 2480 } 2481 2482 int 2483 sshpkt_put_stringb(struct ssh *ssh, const struct sshbuf *v) 2484 { 2485 return sshbuf_put_stringb(ssh->state->outgoing_packet, v); 2486 } 2487 2488 int 2489 sshpkt_getb_froms(struct ssh *ssh, struct sshbuf **valp) 2490 { 2491 return sshbuf_froms(ssh->state->incoming_packet, valp); 2492 } 2493 2494 #ifdef WITH_OPENSSL 2495 #ifdef OPENSSL_HAS_ECC 2496 int 2497 sshpkt_put_ec(struct ssh *ssh, const EC_POINT *v, const EC_GROUP *g) 2498 { 2499 return sshbuf_put_ec(ssh->state->outgoing_packet, v, g); 2500 } 2501 #endif /* OPENSSL_HAS_ECC */ 2502 2503 2504 int 2505 sshpkt_put_bignum2(struct ssh *ssh, const BIGNUM *v) 2506 { 2507 return sshbuf_put_bignum2(ssh->state->outgoing_packet, v); 2508 } 2509 #endif /* WITH_OPENSSL */ 2510 2511 /* fetch data from the incoming packet */ 2512 2513 int 2514 sshpkt_get(struct ssh *ssh, void *valp, size_t len) 2515 { 2516 return sshbuf_get(ssh->state->incoming_packet, valp, len); 2517 } 2518 2519 int 2520 sshpkt_get_u8(struct ssh *ssh, u_char *valp) 2521 { 2522 return sshbuf_get_u8(ssh->state->incoming_packet, valp); 2523 } 2524 2525 int 2526 sshpkt_get_u32(struct ssh *ssh, u_int32_t *valp) 2527 { 2528 return sshbuf_get_u32(ssh->state->incoming_packet, valp); 2529 } 2530 2531 int 2532 sshpkt_get_u64(struct ssh *ssh, u_int64_t *valp) 2533 { 2534 return sshbuf_get_u64(ssh->state->incoming_packet, valp); 2535 } 2536 2537 int 2538 sshpkt_get_string(struct ssh *ssh, u_char **valp, size_t *lenp) 2539 { 2540 return sshbuf_get_string(ssh->state->incoming_packet, valp, lenp); 2541 } 2542 2543 int 2544 sshpkt_get_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp) 2545 { 2546 return sshbuf_get_string_direct(ssh->state->incoming_packet, valp, lenp); 2547 } 2548 2549 int 2550 sshpkt_peek_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp) 2551 { 2552 return sshbuf_peek_string_direct(ssh->state->incoming_packet, valp, lenp); 2553 } 2554 2555 int 2556 sshpkt_get_cstring(struct ssh *ssh, char **valp, size_t *lenp) 2557 { 2558 return sshbuf_get_cstring(ssh->state->incoming_packet, valp, lenp); 2559 } 2560 2561 #ifdef WITH_OPENSSL 2562 #ifdef OPENSSL_HAS_ECC 2563 int 2564 sshpkt_get_ec(struct ssh *ssh, EC_POINT *v, const EC_GROUP *g) 2565 { 2566 return sshbuf_get_ec(ssh->state->incoming_packet, v, g); 2567 } 2568 #endif /* OPENSSL_HAS_ECC */ 2569 2570 int 2571 sshpkt_get_bignum2(struct ssh *ssh, BIGNUM **valp) 2572 { 2573 return sshbuf_get_bignum2(ssh->state->incoming_packet, valp); 2574 } 2575 #endif /* WITH_OPENSSL */ 2576 2577 int 2578 sshpkt_get_end(struct ssh *ssh) 2579 { 2580 if (sshbuf_len(ssh->state->incoming_packet) > 0) 2581 return SSH_ERR_UNEXPECTED_TRAILING_DATA; 2582 return 0; 2583 } 2584 2585 const u_char * 2586 sshpkt_ptr(struct ssh *ssh, size_t *lenp) 2587 { 2588 if (lenp != NULL) 2589 *lenp = sshbuf_len(ssh->state->incoming_packet); 2590 return sshbuf_ptr(ssh->state->incoming_packet); 2591 } 2592 2593 /* start a new packet */ 2594 2595 int 2596 sshpkt_start(struct ssh *ssh, u_char type) 2597 { 2598 u_char buf[6]; /* u32 packet length, u8 pad len, u8 type */ 2599 2600 DBG(debug("packet_start[%d]", type)); 2601 memset(buf, 0, sizeof(buf)); 2602 buf[sizeof(buf) - 1] = type; 2603 sshbuf_reset(ssh->state->outgoing_packet); 2604 return sshbuf_put(ssh->state->outgoing_packet, buf, sizeof(buf)); 2605 } 2606 2607 static int 2608 ssh_packet_send_mux(struct ssh *ssh) 2609 { 2610 struct session_state *state = ssh->state; 2611 u_char type, *cp; 2612 size_t len; 2613 int r; 2614 2615 if (ssh->kex) 2616 return SSH_ERR_INTERNAL_ERROR; 2617 len = sshbuf_len(state->outgoing_packet); 2618 if (len < 6) 2619 return SSH_ERR_INTERNAL_ERROR; 2620 cp = sshbuf_mutable_ptr(state->outgoing_packet); 2621 type = cp[5]; 2622 if (ssh_packet_log_type(type)) 2623 debug3("%s: type %u", __func__, type); 2624 /* drop everything, but the connection protocol */ 2625 if (type >= SSH2_MSG_CONNECTION_MIN && 2626 type <= SSH2_MSG_CONNECTION_MAX) { 2627 POKE_U32(cp, len - 4); 2628 if ((r = sshbuf_putb(state->output, 2629 state->outgoing_packet)) != 0) 2630 return r; 2631 /* sshbuf_dump(state->output, stderr); */ 2632 } 2633 sshbuf_reset(state->outgoing_packet); 2634 return 0; 2635 } 2636 2637 /* 2638 * 9.2. Ignored Data Message 2639 * 2640 * byte SSH_MSG_IGNORE 2641 * string data 2642 * 2643 * All implementations MUST understand (and ignore) this message at any 2644 * time (after receiving the protocol version). No implementation is 2645 * required to send them. This message can be used as an additional 2646 * protection measure against advanced traffic analysis techniques. 2647 */ 2648 int 2649 sshpkt_msg_ignore(struct ssh *ssh, u_int nbytes) 2650 { 2651 u_int32_t rnd = 0; 2652 int r; 2653 u_int i; 2654 2655 if ((r = sshpkt_start(ssh, SSH2_MSG_IGNORE)) != 0 || 2656 (r = sshpkt_put_u32(ssh, nbytes)) != 0) 2657 return r; 2658 for (i = 0; i < nbytes; i++) { 2659 if (i % 4 == 0) 2660 rnd = arc4random(); 2661 if ((r = sshpkt_put_u8(ssh, (u_char)rnd & 0xff)) != 0) 2662 return r; 2663 rnd >>= 8; 2664 } 2665 return 0; 2666 } 2667 2668 /* send it */ 2669 2670 int 2671 sshpkt_send(struct ssh *ssh) 2672 { 2673 if (ssh->state && ssh->state->mux) 2674 return ssh_packet_send_mux(ssh); 2675 return ssh_packet_send2(ssh); 2676 } 2677 2678 int 2679 sshpkt_disconnect(struct ssh *ssh, const char *fmt,...) 2680 { 2681 char buf[1024]; 2682 va_list args; 2683 int r; 2684 2685 va_start(args, fmt); 2686 vsnprintf(buf, sizeof(buf), fmt, args); 2687 va_end(args); 2688 2689 if ((r = sshpkt_start(ssh, SSH2_MSG_DISCONNECT)) != 0 || 2690 (r = sshpkt_put_u32(ssh, SSH2_DISCONNECT_PROTOCOL_ERROR)) != 0 || 2691 (r = sshpkt_put_cstring(ssh, buf)) != 0 || 2692 (r = sshpkt_put_cstring(ssh, "")) != 0 || 2693 (r = sshpkt_send(ssh)) != 0) 2694 return r; 2695 return 0; 2696 } 2697 2698 /* roundup current message to pad bytes */ 2699 int 2700 sshpkt_add_padding(struct ssh *ssh, u_char pad) 2701 { 2702 ssh->state->extra_pad = pad; 2703 return 0; 2704 } 2705