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